Solid Power (SLDP) 10-K 1 Mar 23 2022 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Feb. 27, 2023	Jun. 30, 2022
Document Type	10-K
Document Annual Report	true
Document Transition Report	false
Document Period End Date	Dec. 31, 2022
Entity File Number	001-40284
Entity Registrant Name	SOLID POWER, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	86-1888095
Entity Address State Or Province	CO
Entity Address, Address Line One	486 S. Pierce Ave., Suite E
Entity Address, City or Town	Louisville
Entity Address, Postal Zip Code	80027
City Area Code	303
Local Phone Number	219-0720
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Public Float			$ 815.2
Entity Common Stock, Shares Outstanding		176,782,721
Entity Central Index Key	0001844862
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	FY
Amendment Flag	false
ICFR Auditor Attestation Flag	true
Auditor Name	Ernst & Young LLP
Auditor Firm ID	42
Auditor Location	Denver, Colorado
Common Stock [Member]
Title of 12(b) Security	Common stock, par value $0.0001 per share
Trading Symbol	SLDP
Security Exchange Name	NASDAQ
Warrants, each whole warrant exercisable for one share of common stock at an exercise price of $11.50
Title of 12(b) Security	Warrants, each whole warrant exercisablefor one share of common stock at an
Trading Symbol	SLDPW
Security Exchange Name	NASDAQ

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Current Assets
Cash and cash equivalents	$ 50,123	$ 513,447
Marketable securities	272,957	75,885
Contract receivables	1,840	829
Prepaid expenses and other current assets	2,888	4,216
Total current assets	327,808	594,377
Property, Plant and Equipment, net	82,761	22,082
Right-Of-Use Operating Lease Asset, net	7,725
Right-Of-Use Financing Lease Asset, net	922
Other Assets	1,148	602
Long-term Investments	172,974
Intangible Assets, net	1,108	619
Total assets	594,446	617,680
Current Liabilities
Accounts payable	10,070	4,326
Current portion of long-term debt	7	120
Deferred revenue	4,050	500
Accrued and other current liabilities:
Accrued compensation	4,528	1,151
Other accrued liabilities	1,256	2,269
Operating lease liabilities, short-term	549
Financing lease liability, short-term	273
Total current liabilities	20,733	8,366
Long-term Debt		10
Warrant Liabilities	9,117	50,020
Operating Lease Liabilities, Long-Term	8,622
Financing Lease Liabilities, Long-Term	602
Other Long-term Liabilities		393
Deferred Taxes		226
Total liabilities	39,074	59,015
Stockholders' Equity
Common Stock, $0.0001 par value; 2,000,000,000 shares authorized; 176,007,184 and 167,557,988 shares issued and outstanding as of December 31, 2022 and 2021, respectively	18	17
Additional paid-in capital	577,603	568,183
Accumulated deficit	(19,090)	(9,535)
Accumulated other comprehensive loss	(3,159)
Total stockholders' equity	555,372	558,665
Total liabilities and stockholders' equity	$ 594,446	$ 617,680

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2022	Dec. 31, 2021
Consolidated Balance Sheets
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	2,000,000,000	2,000,000,000
Common stock, shares issued	176,007,184	167,557,988
Common stock, shares outstanding	176,007,184	167,557,988

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Consolidated Statements of Operations
Revenue	$ 11,789	$ 2,712	$ 2,103
Operating Expenses
Direct costs	9,592	3,073	1,670
Research and development	38,592	17,102	9,594
Marketing and sales	3,692	3,428	1,205
General and administrative	19,032	5,655	1,227
Total operating expenses	70,908	29,258	13,696
Operating Loss	(59,119)	(26,546)	(11,593)
Nonoperating Income (Expense)
Interest income	4,692	56	28
Change in fair value of warrant liabilities	40,903	51,233
Interest expense	(42)	(394)	(361)
Other income (expense)	3,784	(3,602)
Loss from change in fair value of debt			(437)
Loss from change in fair value of embedded derivative liability		(2,680)	(2,817)
Gain on loan extinguishment			923
Total nonoperating income (expense)	49,337	44,613	(2,664)
Pretax Income (Loss)	(9,782)	18,067	(14,257)
Income tax (benefit) expense	(227)	(25)	118
Net Income (Loss)	(9,555)	18,092	(14,375)
Premium paid on repurchase of redeemable convertible preferred stock		5,436
Net Income (Loss) Attributable to Common Stockholders	(9,555)	12,656	(14,375)
Other Comprehensive Loss
Unrealized loss on marketable securities	(3,159)
Comprehensive Income (Loss) Attributable to Common Stockholders	$ (12,714)	$ 12,656	$ (14,375)
Basic earnings (loss) per share	$ (0.05)	$ 0.13	$ (0.21)
Diluted earnings (loss) per share	$ (0.05)	$ 0.11	$ (0.21)
Weighted average shares outstanding - basic	174,374,386	95,477,472	69,228,444
Weighted average shares outstanding - diluted	174,374,386	114,910,129	69,228,444

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - USD ($)	Common stock Retroactive Application of Recapitalization	Common stock Adjusted Balance	Common stock	Additional Paid-in Capital Retroactive Application of Recapitalization	Additional Paid-in Capital Adjusted Balance	Additional Paid-in Capital	Accumulated Deficit Retroactive Application of Recapitalization	Accumulated Deficit Adjusted Balance	Accumulated Deficit	Accumulated OCI	Retroactive Application of Recapitalization	Adjusted Balance	Total
Balance at the beginning at Dec. 31, 2019													$ 29,096,000
Balance at the end at Dec. 31, 2020											$ (29,096,000)
Balance at the beginning at Dec. 31, 2019			$ 1,000						$ (16,197,000)				(16,196,000)
Balance at the beginning (in shares) at Dec. 31, 2019			7,213,730
Changes in stockholder's equity
Net income (loss)									(14,375,000)				(14,375,000)
Bank warrant issuance						$ 16,000							16,000
Beneficial Conversion feature on convertible debt						5,125,000							5,125,000
Stock options exercised (in shares)			1,097,370
Stock options exercised			$ 1,097,370			24,000							24,000
Stock-based compensation expense						182,000							182,000
Balance at the end at Dec. 31, 2020	$ 6,000	$ 7,000	$ 7,000	$ 26,145,000	$ 26,145,000	31,492,000	$ 2,945,000	$ (13,252,000)	(27,627,000)		$ 29,096,000	$ 12,900,000	3,872,000
Balance at the end (in shares) at Dec. 31, 2020	61,573,943	68,787,673	69,885,043
Changes in stockholder's equity
Net income (loss)									18,092,000				18,092,000
Business Combination, net of redemptions and transaction costs of $47,888			$ 6,000			394,587,000							394,593,000
Business Combination, net of redemptions and transaction costs of $47,888 (in shares)			63,039,829
Beneficial Conversion feature on convertible debt						4,875,000							4,875,000
Redemption of Series A-1 redeemable preferred stock						(6,041,000)							(6,041,000)
Redemption of Series A-1 redeemable preferred stock (in shares)			(1,065,432)
Issuance of Series B redeemable preferred stock net of issuance costs of $4,511 and settlement of associated convertible preferred stock liability			$ 3,000			140,436,000							140,439,000
Issuance of Series B redeemable preferred stock net of issuance costs of $4,511 and settlement of associated convertible preferred stock liability (in shares)			27,930,997
Warrants exercised			$ 1,000			14,000							15,000
Stock options exercised (in shares)			1,160,930
Warrants exercised (in shares)			6,606,621
Transaction costs													(4,511,000)
Stock options exercised			$ 1,160,930			106,000							106,000
Stock-based compensation expense						2,714,000							2,714,000
Balance at the end at Dec. 31, 2021			$ 17,000			568,183,000			(9,535,000)				558,665,000
Balance at the end (in shares) at Dec. 31, 2021			167,557,988
Changes in stockholder's equity
Net income (loss)									(9,555,000)				(9,555,000)
Withholding of Employee taxes related to stock-based compensation						(58,000)							(58,000)
Shares issued for the vesting of restricted stock units			20,672
Unrealized loss on marketable securities										$ (3,159,000)			(3,159,000)
Stock options exercised (in shares)			8,428,524
Transaction costs						(12,000)							(12,000)
Stock options exercised			$ 1,000			818,000							819,000
Stock-based compensation expense						8,672,000							8,672,000
Balance at the end at Dec. 31, 2022			$ 18,000			$ 577,603,000			$ (19,090,000)	$ (3,159,000)			$ 555,372,000
Balance at the end (in shares) at Dec. 31, 2022			176,007,184

Consolidated Statements of St_2

Consolidated Statements of Stockholders' Equity (Parenthetical) $ in Thousands	12 Months Ended
	Dec. 31, 2021 USD ($)
Consolidated Statements of Stockholders' Equity
Transaction costs	$ 47,888
Stock issuance costs	$ 4,511

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Cash Flows from Operating Activities
Net income (loss)	$ (9,555)	$ 18,092	$ (14,375)
Adjustments to reconcile net income (loss) to net cash and cash equivalents from operating activities:
Depreciation and amortization	5,176	2,360	2,067
Amortization of right-of-use assets	745
Loss on sale of property, plant and equipment	11	11	7
(Gain) on extinguishment of debt			(923)
Stock compensation expense	8,672	2,714	182
Stock warrant issuance			16
Deferred taxes	(227)	(25)	118
Change in fair value of warrant liabilities	(40,903)	(51,233)
Amortization of premiums and accretion of discounts on marketable securities	(3,118)
Accrued interest on convertible notes payable to be paid in kind		263	165
Non-cash interest expense on convertible notes payable			437
Loss from change in fair value of embedded derivative liability		2,680	2,817
Change in operating assets and liabilities that provided (used) cash and cash equivalents:
Contract receivable	(1,012)	(552)	(248)
Due from related party			244
Prepaid expenses and other assets	2,687	(3,865)	23
Accounts payable	(94)	778	(120)
Deferred revenue	3,550	462	(421)
Accrued and other liabilities	645	2,801	77
Operating lease liability	(401)
Deferred rent		74	(61)
Net cash and cash equivalents used in operating activities	(33,824)	(25,440)	(9,995)
Cash Flows from Investing Activities
Purchases of property, plant and equipment	(58,296)	(12,617)	(1,020)
Purchases of marketable securities and long-term investments	(561,565)	(75,885)
Proceeds from sales of marketable securities	190,374
Purchases of intangible assets	(498)	(381)	(40)
Net cash and cash equivalents used in investing activities	(429,985)	(88,883)	(1,060)
Cash Flows from Financing Activities
Proceeds from debt		960	923
Payments of debt	(121)	(3,557)	(676)
Proceeds from issuance of convertible note payable		4,875	5,125
Proceeds from exercise of common stock options	818	106	23
Proceeds from exercise of common stock warrants		15
Proceeds from issuance of Series B preferred stock		135,579
Preferred stock issuance costs		(4,511)
Redemption of preferred stock		(6,041)
Cash paid for withholding of employee taxes related to stock-based compensation	(58)
Payments on finance lease liability	(142)
Business Combination, net of transaction costs		495,370
Transaction costs	(12)
Net cash and cash equivalents provided by financing activities	485	622,796	5,395
Net (decrease) increase in cash and cash equivalents	(463,324)	508,473	(5,660)
Cash and cash equivalents at beginning of period	513,447	4,974	10,634
Cash and cash equivalents at end of period	50,123	513,447	4,974
Supplemental information
Cash paid for interest	42	144	351
Accrued capital expenditures	$ 7,561
Net assets acquired in Business Combination		$ (100,697)
Gain on extinguishment of PPP loan			$ (923)

Nature of Business

Nature of Business	12 Months Ended
	Dec. 31, 2022
Nature of Business
Nature of Business	Note 1 – Nature of Business Solid Power, Inc. (the “Company”) is developing solid state battery technology to enable the next generation of batteries for the fast-growing EV and other markets. The Company’s planned business model is to sell its sulfide-based solid electrolyte and to license its solid-state cell designs and manufacturing processes. For the years ended December 31, 2022, 2021, and 2020, the Company has not derived material revenue from its principal business activities. On December 8, 2021 (the “Closing Date”), the Company (f/k/a Decarbonization Plus Acquisition Corporation III (“DCRC”)) consummated its previously announced business combination pursuant to the Business Combination Agreement and Plan of Reorganization, dated June 15, 2021 (as amended, the “Business Combination Agreement”), among the Company, DCRC Merger Sub Inc., a Delaware corporation and wholly owned subsidiary of DCRC (“Merger Sub”), and Solid Power Operating, Inc., a Colorado corporation (f/k/a Solid Power, Inc., “Legacy Solid Power”). Pursuant to the terms of the Business Combination Agreement, Merger Sub merged with and into Legacy Solid Power, with Legacy Solid Power surviving the merger as a wholly owned subsidiary of the Company (the “Merger” and, together with the other transactions contemplated by the Business Combination Agreement, the “Business Combination”).

Significant Accounting Policies

Significant Accounting Policies	12 Months Ended
	Dec. 31, 2022
Significant Accounting Policies
Significant Accounting Policies	Note 2 – Significant Accounting Policies Basis of Presentation and Principles of Consolidation The Consolidated Financial Statements of the Company have been prepared on the basis of generally accepted accounting principles in the United States (“GAAP”). The preparation of Consolidated Financial Statements in conformity with GAAP requires management to make estimates and assumptions that affect amounts reported in the Consolidated Financial Statements. Actual results could differ from those estimates. All amounts presented in the footnotes are in thousands, except share and per share amounts. Pursuant to the Business Combination Agreement, the merger between Merger Sub and Legacy Solid Power was accounted for as a reverse recapitalization in accordance with GAAP (the “Reverse Recapitalization”). Under this method of accounting, DCRC was treated as the “acquired” company and Legacy Solid Power is treated as the acquirer for financial reporting purposes. Accordingly, for accounting purposes, the Reverse Recapitalization was treated as the equivalent of Legacy Solid Power issuing stock for the net assets of DCRC, accompanied by a recapitalization. The net assets of DCRC are stated at historical cost, with no goodwill or other intangible assets recorded. The consolidated assets, liabilities, and results of operations prior to the Reverse Recapitalization are those of Legacy Solid Power. The shares and corresponding capital amounts and losses per share, prior to the Business Combination, have been retroactively restated based on the Exchange Ratio (defined below). The Consolidated Financial Statements include accounts of the Company and its wholly owned subsidiary, Solid Power Operating, Inc. All intercompany balances and transactions have been eliminated in consolidation. The accompanying Consolidated Financial Statements have been prepared assuming that the Company will continue as a going concern. Segment Reporting The Company’s Chief Operating Decision Maker (“CODM”) is its Chief Executive Officer. The Company has determined that it operates in one operating segment and one reportable segment, as the CODM reviews financial information presented as a single entity for purposes of making operating decisions, allocating resources, and evaluating financial performance. Use of Estimates The preparation of financial statements in accordance with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, and contingencies at the date of the financial statements as well as reported amounts of revenues and expenses during the reporting periods. Estimates made by the Company include, but are not limited to, those related to the valuation of common stock prior to the Business Combination, valuation of stock warrants, and useful lives of long-term assets, among others. The Company bases these estimates on historical experience and other assumptions that it believes are reasonable under the circumstances. Cash and Cash Equivalents The Company considers all highly liquid investments with an original maturity of three months or less when purchased to be cash equivalents. As of December 31, 2022 and periodically throughout the year, the Company’s cash accounts exceeded federally insured limits. Marketable Securities The Company’s investment policy is consistent with the definition of available-for-sale securities. The Company does not buy and hold securities principally for the purpose of selling them in the near future. The Company’s policy is focused on the preservation of capital, liquidity, and return. From time to time, the Company may sell certain securities, but the objectives are not to generate profits on short-term differences in price. These securities are carried at estimated fair value with unrealized holding gains and losses included in other comprehensive loss in stockholders’ deficit until realized. Gains and losses on marketable security transactions are reported on the specific-identification method. Dividend and interest income are recognized when earned. Contract Receivables Contract receivables consist of amounts due from government entities and commercial contractors. Management considers all contract receivables collectible, and therefore, an allowance for doubtful accounts has not been recorded as of December 31, 2022 and 2021. Included within contract receivables are amounts for work performed but not billed as of December 31, 2022 and 2021, shown below. ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2022 December 31, 2021 Contract receivables not billed ​ $ 1,083 ​ $ 310 ​ Credit Risk and Major Customers Financial instruments that potentially subject the Company to credit risk consist principally of cash and cash equivalents, marketable securities, and long-term investments. The Company seeks to mitigate its credit risk with respect to cash and cash equivalents, marketable securities, and long-term investments by making deposits with several large, reputable financial institutions and investing in high credit rated instruments. The Company grants credit in the normal course of business to government entities and commercial contractors in the United States. The Company periodically performs credit analyses and monitors the financial condition of its customers to reduce credit risk. The Company performs ongoing credit evaluations of its customers, but generally does not require collateral to support contract receivables. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the Years Ended December 31, ​ 2022 2021 2020 Revenue Concentration ​ ​ ​ ​ Number of Customers ​ 4 4 3 ​ Related Total Revenue Percentage 82 % 87 % 81 % Contract Receivable Concentration ​ Number of Customers 2 2 1 ​ Related Contract Receivables Percentage 40 % 58 % 18 % ​ Prepaid Expenses and Other Current Assets Prepaid expenses and other current assets consist primarily of security deposits, prepaid Directors and Officers insurance and other minor miscellaneous expenses paid in advance. Property and Equipment Property and equipment are recorded at cost. The Company capitalizes property and equipment with useful lives exceeding one year. Assets are depreciated over their estimated useful lives. The straight-line method is used for computing depreciation and amortization. Depreciation and amortization expenses are recorded within the Direct costs and Research and development line items in the Consolidated Statements of Operations. Cost of maintenance and repairs are charged to expense when incurred. Construction in progress related to specialized equipment will be reclassified as Property and equipment and depreciated, once placed in service. ​ ​ ​ ​ ​ Depreciable Life - Years Commercial production equipment ​ 5 years Laboratory equipment ​ 5 years Furniture and Computer Equipment 3-7 years Leasehold improvements Lesser of asset life or lease term ​ Long-Term Investments The Company considers all investments with an original maturity of twelve months or more when purchased to be long-term investments. Intangible Assets Intangible assets consist of licenses and costs incurred for pending patents and pending trademarks. Licenses consist of rights to use patents and are amortized over their estimated useful life of three Deferred Rent Prior to the adoption of ASU No. 2016-02, Leases (Topic 842) on January 1, 2022, the Company had entered into operating lease agreements for each of its two facilities, each of which contain provisions for future rent increases or periods in which rent payments are reduced. The Company records monthly rent expense equal to the total of the payments due over the lease term, divided by the number of months of the lease term. The difference between rent expense recorded and the amount paid is credited or charged to deferred rent, which is reflected in Other Long-term Liabilities in the accompanying Consolidated Balance Sheets. Deferred rent also includes the unamortized portion of landlord-financed tenant improvement allowances, which are amortized on a straight-line basis over the lease term as a reduction in rent expense. Leases The Company accounts for its leases under ASU No. 2016-02, Leases (Topic 842). Under this guidance, the Company classifies contracts meeting the definition of a lease as operating or financing leases, and leases are recorded on the condensed consolidated balance sheet as both a right-of-use asset and lease liability, calculated by discounting fixed lease payments over the lease term at the rate implicit in the lease or the Company’s incremental borrowing rate. Lease liabilities are increased by interest and reduced by payments each period, and the right-of-use asset is amortized over the lease term. For operating leases, interest on the lease liability and the amortization of the right-of-use asset result in straight-line rent expense over the lease term. For finance leases, interest on the lease liability and the amortization of the right-of-use asset results in front-loaded expense over the lease term. Variable lease expenses, including common maintenance fees, insurance and property tax, are recorded when incurred. In calculating the right-of-use asset and lease liability, the Company elects to combine lease and non-lease components for all classes of assets. The Company excludes short-term leases having initial terms of 12 months or less as an accounting policy election, and instead recognizes rent expense on a straight-line basis over the lease term. Stock-based Compensation The Company recognizes expenses for employee services received in exchange for stock-based compensation based on the grant date fair value of the awards. The determination of the estimated fair value of stock-based payment awards on the date of grant using the Black-Scholes option-pricing model is affected by the Company’s stock price, as well as assumptions regarding risk-free rate, dividend yield, and the historical volatility of comparable entities. Stock-based compensation is recorded as an expense only for those awards that are expected to vest. Compensation cost is recognized on a straight-line basis over the requisite vesting service period and is allocated ratably within Operating Expenses in the Consolidated Statements of Operations. Revenue The Company records the elements of its joint development agreements that represent joint operating activities in accordance with Accounting Standards Codification (ASC) Topic 808, Collaborative Arrangements. Accordingly, the elements of the joint development agreements that represent activities in which both parties are active participants and to which both parties are exposed to the significant risks and rewards that are dependent on the commercial success of the activities are recorded as collaborative arrangements. The Company considers the guidance in ASC 606-10-15, Revenue from Contracts with Customers – Scope and Scope Exceptions, in determining the appropriate treatment for the transactions between the Company and its partners and the transactions between the Company and third parties. Generally, the classification of transactions under the joint development agreements is determined based on the nature and contractual terms of the arrangement along with the nature of the operations of the participants. The Company recognizes collaborative revenue from cost contracts on the basis of costs incurred during the period and cost plus fixed-fee contracts on the basis of costs incurred during the period plus the fee earned. Contract costs include all direct labor, subcontract, material, and indirect costs related to the contract performance that are allowable under contract provisions. Unbilled receivables are included in contract receivables and represent revenue recognized for which billings have not yet been presented to customers. Deferred revenue represents billings in advance of revenue recognized. Deferred revenue as of December 31, 2022 and 2021 was $4,050 and $500, respectively. Beneficial Conversion Feature and Embedded Derivatives The beneficial conversion feature (the “BCF”) of a convertible note is normally characterized as the convertible portion or feature of certain notes payable that provide a rate of conversion that is below market value or in-the-money when issued. For convertible debt where the rate of conversion is below market value, the Company records a BCF and related debt discount. When Legacy Solid Power recorded a BCF, the intrinsic value of the BCF was recorded in equity to Additional paid-in capital and the difference between the debt proceeds and the BCF was a debt discount against the face amount of the respective debt instrument and amortized to interest expense over the life of the debt. A separate embedded derivative was recognized as a derivative liability that was subsequently adjusted to fair value at each Consolidated Balance Sheet date. Embedded derivatives that are required to be bifurcated from the underlying debt instrument (i.e., host) are accounted for and valued as separate financial instruments. Legacy Solid Power evaluated the terms and features of its 2020 convertible promissory notes (as defined below) and identified embedded derivatives requiring bifurcation and accounting at fair value, using the valuation techniques mentioned in the Fair Value Measurements section of this Note, because the economic and contractual characteristics of the embedded derivatives met the criteria for bifurcation and separate accounting due to the instruments containing mandatory redemption features that were not clearly and closely related to the debt host instrument. Warrant Liabilities The Company accounts for warrants as liability-classified instruments based on an assessment of the warrant’s specific terms and applicable authoritative guidance in ASC 480 and ASC 815. Warrants recorded as liabilities are recorded at their fair value, within Warrant Liabilities on the Consolidated Balance Sheets and are remeasured on each reporting date with changes recorded in Change in fair value of warrant liabilities on the Company’s Consolidated Statements of Operations. Fair Value Measurements The Company applies fair value accounting for selected financial assets and liabilities measured on a recurring and nonrecurring basis. Fair value is defined as an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or a liability. The accounting guidance ASC Topic 820 Fair Value Measurement established a fair value hierarchy based on three levels of inputs, of which the first two are considered observable and the last unobservable, used to determine the fair value of its financial instruments. A financial instrument’s level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement. Level 1 – inputs include quoted market prices in an active market for identical assets or liabilities. Level 2 – inputs are market data, other than Level 1, that are observable either directly or indirectly. Level 2 inputs include quoted market prices for similar assets or liabilities, quoted market prices in an inactive market, and other observable information that can be corroborated by market data. Level 3 – inputs are unobservable and corroborated by little or no market data. Research and Development Research and development expenditures of approximately $38,592, $17,102 and $9,594 in 2022, 2021 and 2020, respectively, were charged to expense as incurred. Income Taxes The Company recognizes deferred tax liabilities and assets for the expected future tax consequences of events that have been included in the Consolidated Financial Statements or tax returns. Deferred tax liabilities and assets are determined based on the differences between the Consolidated Financial Statements and tax basis of assets and liabilities using the enacted tax rates in effect for the year in which the differences are expected to reverse. The measurement of deferred tax assets is reduced, if necessary, by the amount of any uncertain tax positions or tax benefits that are not expected to be realized based on available evidence. The Company records deferred tax assets and associated valuation allowances, when appropriate, to reflect amounts more likely than not to be realized based upon Company analysis. The Company’s temporary differences result primarily from capitalization of certain qualifying research and development expenses, accruals and reserves, depreciation of property and equipment, stock compensation expense, capitalization of operating or financing leases, and net operating loss carryovers. The Company accounts for any uncertainty in income taxes by recognizing the tax benefit from an uncertain tax position only if it is more likely than not that the tax position will be sustained on examination by the taxing authorities, based on the technical merits of the position. The Company measures the tax benefits recognized in the Consolidated Financial Statements from such a position based on the largest benefit that has a greater than 50 percent likelihood of being realized upon ultimate resolution. Interest and penalties associated with tax positions are recorded in the period assessed as General and administrative on the Consolidated Statement of Operations. No interest or penalties have been assessed during the years ended December 31, 2022, 2021 and 2020. Net Earnings (Loss) per Share of Common Stock Basic net earnings (loss) per share is computed by dividing the net loss by the weighted-average number of shares of common stock outstanding during the period. Diluted earnings per share adjusts basic earnings per share for the potentially dilutive impact of stock options and warrants. The Company reported a net loss in 2022 and 2020. As such all potentially dilutive securities including options and warrants, are antidilutive and accordingly, basic net loss per share equals diluted loss per share. As the Company reported net income in 2021, diluted earnings per share reflected any dilutive effect of stock options and warrants. Mezzanine Equity In accordance with ASC 480, Legacy Solid Power’s Series A-1 Preferred Stock and Series B Preferred Stock (collectively, “Preferred Stock”) prior to the Business Combination were classified as mezzanine equity as the Preferred Stock included redemption features that were not solely within control of Legacy Solid Power. Immediately prior to the consummation of the Business Combination, 14,069,187 shares of Legacy Solid Power Series A-1 Preferred Stock and 8,777,812 shares of Legacy Solid Power Series B Preferred Stock, which represented all of the then-outstanding shares of Preferred Stock, converted to Legacy Solid Power common stock on a one-to-one basis. At the Closing (as defined below), all shares of Legacy Solid Power common stock were exchanged for shares of Solid Power Common Stock based on the Exchange Ratio. Recent Accounting Pronouncements Leases In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842), followed by other related ASUs that provided targeted improvements and additional practical expedient options. On January 1, 2022, the Company adopted the standards under Topic 842 using the modified retrospective method and elected a number of the practical expedients in its implementation of Topic 842. The key change that affected the Company relates to accounting for operating leases for which it is the lessee that were historically off-balance sheet. The impact of adopting the standards resulted in the recognition of a right-of-use asset of $7,853 and lease liability of $8,246 on the Company’s condensed consolidated balance sheet on January 1, 2022, exclusive of previously recognized lease balances. The implementation of Topic 842 did not have a material effect on the Company’s condensed consolidated statement of operations or condensed consolidated statement of cash flows for the year ended December 31, 2022. Financial Instruments In June 2016, the FASB issued ASU 2016-13, Financial Instruments – Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments. This guidance introduces a new model for recognizing credit losses on financial instruments based on an estimate of current expected credit losses. ASU 2016-13 also provides updated guidance regarding the impairment of available-for-sale debt securities and includes additional disclosure requirements. The Company adopted this guidance as of January 1, 2022. The Company regularly reviews its available-for-sale marketable securities and evaluates the current expected credit losses by considering factors such as any changes in credit ratings, historical experience, market data, issuer-specific factors, and current economic conditions. Based on this analysis, an allowance for credit losses is recorded as a reduction to the carrying value of the asset. To date, management has not recorded an allowance for credit losses. The Company reviews its receivable aging on an individual customer level, considering collectability of cash flows based on the risk of past events, current conditions, and forward-looking information. The Company establishes allowances for bad debts equal to the estimable portions of accounts receivable for which failure to collect is expected to occur. Allowances for doubtful accounts are recorded as reductions to the carrying values of the related receivables. To date, the Company has not recorded an allowance for doubtful accounts. Income taxes In December 2019, the FASB issued ASU No. 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes (“ASU 2019-12”), which aims to reduce complexity in accounting standards by improving certain areas of GAAP without compromising information provided to users of financial statements. ASU 2019-12 is effective for public entities for fiscal years beginning after December 15, 2020, and interim periods within those fiscal years. For all other entities, the standard is effective for fiscal years beginning after December 15, 2021, and interim periods within fiscal years beginning after December 15, 2022. The Company adopted this guidance beginning January 1, 2022 with no financial statement impact at adoption.

Business Combination

Business Combination	12 Months Ended
	Dec. 31, 2022
Business Combination
Business Combination	Note 3 – Business Combination Legacy Solid Power was deemed the accounting acquirer in the Business Combination based on the analysis of the criteria outlined in ASC 805. Accordingly, for accounting purposes, the Business Combination was treated as the equivalent of Legacy Solid Power issuing stock for the net assets of DCRC, accompanied by a recapitalization. The net assets of DCRC are stated at historical cost, with no goodwill or other intangible assets recorded. Because Legacy Solid Power was deemed the accounting acquirer, the historical Consolidated Financial Statements of Legacy Solid Power became the historical Consolidated Financial Statements of the combined company. As a result, the Consolidated Financial Statements included in this report reflect (i) the historical operating results of Legacy Solid Power prior to the Business Combination; (ii) the combined results of the Company and Legacy Solid Power following the closing of the Business Combination (“Closing”); (iii) the assets and liabilities of Legacy Solid Power at their historical cost; and (iv) the Company’s equity structure for all periods presented as discussed below. In accordance with guidance applicable to the Business Combination, the equity structure has been restated in all comparative periods up to the Closing Date, to reflect the number of shares of the Company’s Common Stock, $0.0001 par value per share issued to Legacy Solid Power’s stockholders in connection with the Business Combination. As such, the shares and corresponding capital amounts and earnings per share related to Legacy Solid Power redeemable convertible preferred stock and common stock prior to the Business Combination have been retroactively restated to reflect the Exchange Ratio. Activity within the Consolidated Statements of Stockholders’ Equity for the issuances and repurchases of Legacy Solid Power’s redeemable convertible preferred stock were also retroactively converted to Legacy Solid Power common stock. In connection with the Closing, and subject to the terms and conditions of the Business Combination Agreement, each outstanding share of Legacy Solid Power’s common stock (including shares of Legacy Solid Power common stock issued upon the conversion of each share of Legacy Solid Power’s Preferred Stock immediately prior to the Closing) was canceled and converted into the right to receive the number of shares of the Company’s Common Stock (as defined below) based on an Exchange Ratio equal to approximately 3.182 (the “Exchange Ratio”), and each outstanding Legacy Solid Power option issued under Legacy Solid Power’s 2014 Equity Incentive Plan (the “2014 Plan”) was converted into a Company option based on the Exchange Ratio applicable to shares of Legacy Solid Power common stock, each in accordance with the terms of the Business Combination Agreement. At the Closing, the Company issued an aggregate of 104,518,159 shares of Common Stock to the equity-holders of Legacy Solid Power and the Legacy Solid Power option-holders’ held options in the Company to receive an aggregate 34,407,949 shares of Common Stock, subject to payment of the applicable exercise price and, in certain circumstances, vesting obligations. Furthermore, in connection with the Business Combination, (i) all shares of DCRC’s Class A common stock prior to the Business Combination were re-designated as “Common Stock, par value $0.0001 per share” of the Company (“Common Stock”) and (ii) all 40,000 shares of DCRC’s Class B common stock were converted, on a one -for-one basis, into an equivalent number of shares of the Company’s Common Stock. On the Closing Date, a number of purchasers, purchased from DCRC an aggregate of 19,500,000 shares of the Company’s Common Stock, for a purchase price of $10.00 per share and an aggregate purchase price of $195,000 (the “PIPE Financing”), pursuant to separate subscription agreements (each, a “Subscription Agreement”) entered into on June 15, 2021 or October 27, 2021. Prior to the Closing, DCRC had $1,500 outstanding under working capital loans from Decarbonization Plus Acquisition Sponsor III LLC (the “Sponsor”), which, in connection with the Closing, the Sponsor elected to convert into warrants to purchase 1,000,000 shares of Common Stock at a price of $1.50 per share, which are included in the 7,666,667 Private Placement Warrants (as defined below). Pursuant to the Business Combination Agreement, the Merger was accounted for as a Reverse Recapitalization in accordance with GAAP. Under this method of accounting, DCRC was treated as the “acquired” company and Legacy Solid Power is treated as the acquirer for financial reporting purposes. The following table reconciles the elements of the Business Combination to the Consolidated Statements of Cash Flows and the Consolidated Statements of Stockholders’ Equity for the year ended December 31, 2021: ​ ​ ​ ​ ​ ​ Recapitalization Cash – DCRC trust and cash, net of redemptions ​ $ 347,914 Cash – PIPE Financing ​ 195,000 Cash – Sponsor Funds ​ 264 Non-cash net assets acquired from DCRC ​ (100,697) Less: transaction costs and advisory fees for Legacy Solid Power allocated to equity ​ (5,991) Less: transaction costs and advisory fees for DCRC ​ (41,897) Net Business Combination ​ $ 394,593 Add: non-cash net assets acquired from DCRC ​ 100,697 Add: accrued transaction costs and advisory fees ​ 80 Net cash contributions from Business Combination ​ $ 495,370 ​ Non-cash net assets acquired from DCRC include the fair value of acquired Common Stock warrants of ($101,253). The following table sets forth the number of shares of Common Stock outstanding immediately following the consummation of the Business Combination: ​ ​ ​ ​ ​ Number of Shares DCRC Class A common stock outstanding prior to Business Combination 43,710,000 DCRC Class B common stock outstanding prior to Business Combination 40,000 Less: redemption of DCRC Class A common stock (210,171) Shares of Common Stock issued in PIPE Financing 19,500,000 Shares of Common Stock issued to Legacy Solid Power stockholders 104,518,159 Total shares of Common Stock outstanding immediately after Business Combination 167,557,988 ​

Property, Plant and Equipment

Property, Plant and Equipment	12 Months Ended
	Dec. 31, 2022
Property, Plant and Equipment
Property, Plant and Equipment	Note 4 – Property, Plant and Equipment Property, plant and equipment at December 31 are summarized as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ 2022 2021 Commercial production equipment ​ $ 21,595 ​ $ 9,139 Laboratory equipment ​ ​ 3,278 ​ ​ 1,316 Leasehold improvements ​ 27,996 ​ 4,674 Furniture and computer equipment ​ 1,482 ​ 737 Construction in progress ​ 40,036 ​ 12,684 Total cost ​ 94,387 ​ 28,550 Accumulated depreciation ​ (11,626) ​ (6,468) Net property and equipment ​ $ 82,761 ​ $ 22,082 ​ Depreciation expenses are allocated ratably across operating expenses on the accompanying Consolidated Statements of Operations. Depreciation expenses for dedicated laboratory equipment and commercial production equipment are charged to research and development; other depreciation expenses are included in the Company’s overhead and are allocated across operating expenses on the accompanying Consolidated Statements of Operations based on Company personnel costs incurred. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ 2022 2021 2020 ​ ​ ​ ​ ​ ​ ​ Depreciation expense ​ $ 5,167 ​ $ 2,351 ​ $ 2,066 ​ In 2022, the Company expanded its cell production capabilities through the construction of a second dry room and installation of a second cell pilot production line at its Louisville, Colorado facility, which is designed to produce larger format solid-state battery cells for the automotive qualification process. The Company is expanding its electrolyte production to a second location in Thornton, Colorado. Scaling this production will allow it to produce larger quantities of electrolyte material required to feed cell-production lines and continue research and development efforts. The Company expects to begin producing electrolyte from this facility in 2023. ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2022 December 31, 2021 Construction in progress ​ ​ Louisville, Colorado – 2 nd ​ $ 2,010 ​ $ 6,875 Louisville, Colorado – Other capital projects ​ 2,206 ​ — Thornton, Colorado – Increased scale electrolyte production ​ 35,820 ​ 943 ​

Intangible Assets

Intangible Assets	12 Months Ended
	Dec. 31, 2022
Intangible Assets
Intangible Assets	Note 5 – Intangible Assets Intangible assets of the Company at December 31 are summarized as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2022 2021 ​ ​ Gross Carrying ​ Accumulated ​ Gross Carrying ​ Accumulated ​ Amount Amortization Amount Amortization Intangible assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Licenses ​ $ 149 ​ $ (51) ​ $ 149 ​ $ (42) Patents pending ​ 984 ​ — ​ 503 ​ — Trademarks and trademarks pending ​ 26 ​ — ​ 9 ​ — Total amortized intangible assets ​ $ 1,159 ​ $ (51) ​ $ 661 ​ $ (42) ​ Amortization expense for intangible assets totaled $9 for the years ended December 31, 2022, 2021 and 2020. Useful lives of intangible assets range from three

Long-term Debt

Long-term Debt	12 Months Ended
	Dec. 31, 2022
Long-term Debt
Long-term Debt	Note 6 – Long-term Debt Long-term debt at December 31 is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ 2022 2021 Various equipment notes payable to banks in monthly installments ranging from $1 to $2 , including interest at 6.255 percent to 12.18 percent maturing from April 2022 through April 2023. The notes are collateralized by the financed equipment. ​ $ 7 ​ $ 130 Total ​ 7 ​ 130 Less current portion ​ 7 ​ 120 Long-term portion ​ $ — ​ $ 10 ​ The remaining balance of debt is all short-term. The Company anticipates paying off the remaining balance in the subsequent year. Note Payable On December 7, 2021, prior to the Closing, the Company used available cash to pay off the outstanding balance and remaining fees of a note payable to a commercial bank. The Company was in compliance with all financial covenants through the loan payoff on December 7, 2021. Interest expense on long-term debt for the years ended December 31, 2022, 2021 and 2020 was $6, $131 and $196, respectively.

Convertible Notes Payable

Convertible Notes Payable	12 Months Ended
	Dec. 31, 2022
Convertible Notes Payable,
Convertible Notes Payable	Note 7 – Convertible Notes Payable 2020 Convertible Promissory Notes On December 10, 2020 and December 18, 2020, the Company issued unsecured convertible promissory notes to investors in the total principal amount of $5,125, and on February 4, 2021, and March 1, 2021, the Company issued additional unsecured convertible promissory notes to investors in the total principal amount of $4,875, as part of a single financing (collectively, the “2020 Notes”). The 2020 Notes accrued interest at eight percent per annum. The 2020 Notes were converted into 1,007,965 shares of Legacy Solid Power Series B Preferred Stock on May 5, 2021, in conjunction with the closing of the Legacy Solid Power Series B Preferred Stock (“Series B Financing”). The outstanding balance on the 2020 Notes, including accrued interest, was $10,228 when the 2020 Notes were converted to Legacy Solid Power Series B Preferred Stock. Interest expense for 2021 was $210 for the 2020 Notes. The principal of the 2020 Notes was included in Additional paid-in capital and the fair value of the embedded derivative was recorded as a liability on the Legacy Solid Power’s Consolidated Balance Sheet. The fair value of the embedded derivative was $5,497. This balance was transferred, along with the accrued interest, to mezzanine equity upon conversion of the 2020 Notes to Series B Preferred Stock in conjunction with the Series B Financing. 2020 Convertible Promissory Notes Embedded Derivative The 2020 Notes contained the following embedded derivatives: (i) a share settled redemption upon Qualified Financing; (ii) share settled redemption upon De-SPAC and; (iii) share settled redemption at maturity. Embedded derivatives are separated from the host contract and carried at fair value when: (a) the embedded derivative possesses economic characteristics that are not clearly and closely related to the economic characteristics of the host contract; and (b) a separate, stand-alone instrument with the same terms would qualify as a derivative instrument. The Company has concluded that certain embedded derivatives within the 2020 Notes meet these criteria and, as such, must be valued separate and apart from the 2020 convertible promissory notes as one embedded derivative and recorded at fair value each reporting period. 2019 Convertible Promissory Notes On December 4, 2019, the Company issued an unsecured convertible promissory note to an investor in the principal amount of $3,000 (the “2019 Note,” and together with the 2020 Notes, the “Convertible Promissory Notes”). The 2019 Note accrued interest at 5 percent per annum. The 2019 Note converted into 254,899 shares of Legacy Solid Power Series B Preferred Stock, in conjunction with the Series B Financing. Upon this conversion, the 2019 Note converted to Series B Preferred Stock at a 30 percent discount. Interest expense incurred for the year ended December 31, 2020 was $150. Prior to conversion, interest expense incurred for the year ended December 31, 2020 was $53. For all debt instruments, including any for which the Company has elected fair value accounting, the Company classifies interest that has been accrued during each period as Interest expense on the Consolidated Statements of Operations.

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2022
Fair Value Measurements
Fair Value Measurements	Note 8 – Fair Value Measurements The Company considers all highly liquid instruments with original maturities of less than 90 days to be cash equivalents. As of December 31, 2022, there were no long-term marketable securities. The carrying amounts of certain financial instruments, such as cash equivalents, short-term investments, accounts receivable, accounts payable and accrued liabilities, approximate fair value due to their relatively short maturities. The fair value of debt instruments for which the Company has not elected fair value accounting is based on the present value of expected future cash flows and assumptions about the then-current market interest rates as of the reporting period and the creditworthiness of the Company. The book values of the Company’s long-term debt approximate fair value because interest rates charged are similar to other financial instruments with similar terms and maturities and the rates vary in accordance with a market index. Most of the Company’s debt is carried on the Consolidated Balance Sheets on a historical cost basis net of unamortized discounts and premiums because the Company has not elected the fair value option of accounting. Changes to the inputs used in these valuation models can have a significant impact on the estimated fair value of the Convertible Promissory Notes and the Company’s embedded derivatives. Assets and Liabilities Measured and Recorded at Fair Value on a Recurring Basis As discussed in Note 7, all Convertible Promissory Notes were converted to Legacy Solid Power Series B Preferred Stock in May 2021. As of December 31, 2022 and 2021, the Company’s financial liabilities measured and recorded at fair value on a recurring basis were classified within the fair value hierarchy as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2022 ​ Level 1 Level 2 Level 3 Total Assets ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Commercial Paper ​ $ 165,179 ​ $ — ​ $ — ​ $ 165,179 Corporate Bonds ​ $ 227,957 ​ $ — ​ $ — ​ $ 227,957 Government Bonds ​ $ 42,865 ​ $ — ​ $ — ​ $ 42,865 U.S. Treasuries ​ 9,930 ​ ​ — ​ ​ — ​ 9,930 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Liabilities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Public Warrants ​ $ 4,900 ​ $ — ​ $ — ​ $ 4,900 Private Warrants ​ $ — ​ $ 4,217 ​ $ — ​ $ 4,217 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2021 ​ Level 1 Level 2 Level 3 Total Assets ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Commercial Paper ​ $ 33,275 ​ $ — ​ $ — ​ $ 33,275 Corporate Bonds ​ $ 39,593 ​ $ — ​ $ — ​ $ 39,593 Government Bonds ​ $ 3,017 ​ $ — ​ $ — ​ $ 3,017 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Liabilities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Public Warrants ​ $ 26,483 ​ $ — ​ $ — ​ $ 26,483 Private Warrants ​ $ — ​ $ 23,537 ​ $ — ​ $ 23,537 ​ The change in fair value of the Company’s marketable securities is included in Other Comprehensive loss. There were no transfers in and out of Level 3 fair value hierarchy during the years ended December 31, 2022 and 2021. For the year ended December 31, 2022 the Company purchased $561,565 of marketable securities. Fair Value Methodology 2020 Notes Embedded Derivative The fair value of the 2020 Notes was estimated using the present value of probability weighted scenario analysis, considering the as-converted value and the downside protection. The embedded derivative is valued using a “with-and-without method,” where the value of the 2020 Notes, including the embedded derivative, is defined as the “with”, and the value of the 2020 Notes, excluding the embedded derivative, is defined as the “without.” This method estimates the value of the embedded derivative by comparing the difference in the values between the 2020 Notes with the embedded derivative and the value of the 2020 Notes, without the embedded derivative. The probability weighted scenario analysis requires the following inputs: (i) probability of qualified financing, maturity, and other contingent scenarios; (ii) equity value; (iii) conversion price; (iv) maturity date; (v) risk-free interest rate; and (vi) estimated volatility. The changes during the twelve months ended December 31, 2021 in the fair values of the embedded derivatives are primarily related to the change in the value of the conversion features and are reflected in the Consolidated Statements of Operations as “Loss from change in fair value of embedded derivative liability.” The embedded derivative liability was settled as of December 31, 2021. Fair Value of Debt - 2019 Note The 2019 Note was converted to Legacy Solid Power Series B Preferred Stock in May 2021. At December 31, 2020, the contractual outstanding principal of the 2019 Note was $3,000, and the fair value was $3,612. The fair value was estimated using the present value of probability weighted scenario analysis, considering the as-converted value and the downside protection. The probability weighted scenario analysis requires the following inputs: (i) probability of qualified financing, maturity and other contingent scenarios; (ii) equity value; (iii) conversion price; (iv) maturity date; (v) risk-free interest rate; and (vi) estimated volatility. Fair Value of Common Stock Warrant Liabilities The fair value of the Private Placement Warrant Liabilities have been estimated using a Black-Scholes model as of the Closing Date and subsequently as of the December 31, 2022 and 2021 Consolidated Balance Sheet dates. The fair value of the Public Warrants (defined below) has been measured based on the quoted price of such warrants on the Nasdaq Stock Market, a Level 1 input. The estimated fair value of the Private Placement Warrants (defined below) is determined using Level 2 inputs. Inherent in a Black-Scholes model are assumptions related to expected stock-price volatility, expected life, risk-free interest rate and dividend yield. Material increases (or decreases) in any of those inputs may result in a significantly higher (or lower) fair value measurement. The Company estimates the volatility of its Private Placement Warrants based on implied volatility from the Company’s Public Warrants and from historical volatility of select peer company’s common stock that matches the expected remaining life of the warrants. The risk-free interest rate is based on the U.S. Treasury zero-coupon yield curve for a maturity similar to the expected remaining life of the warrants. The expected life of the warrants is assumed to be equivalent to their remaining contractual term. The dividend yield is based on the historical rate, which the Company anticipates remaining at zero. The following table provides quantitative information regarding Level 2 inputs used in the recurring valuation of the Private Placement Warrants as of their measurement dates: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2022 December 31, 2021 Exercise Price ​ $ 11.50 ​ $ 11.50 ​ Stock Price ​ $ 2.54 ​ $ 8.74 ​ Volatility ​ 71.3 % 48.9 % Term ​ 3.94 ​ 4.94 ​ Risk-free rate ​ 4.03 % 1.24 % ​ The following table provides a reconciliation of the Public Warrants measured at fair value using Level 1 directly observable inputs and Private Placement Warrants measured at fair value using Level 2 directly or indirectly observable inputs: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Public Warrants ​ Private Warrants ​ Level 1 Fair Value Level 2 Fair Value December 31, 2021 ​ $ 2.27 ​ $ 3.07 Change in fair value ​ $ (1.85) ​ $ (2.52) December 31, 2022 ​ $ 0.42 ​ $ 0.55 ​ The following tables provides a reconciliation of the change in fair value for the Public and Private Placement Warrants for the years ended December 31, 2022 and 2021. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ Change in Fair ​ December 31, Warrant Class Level Shares 2021 Value 2022 Public Warrants 1 11,666,636 ​ $ 26,483 ​ $ (21,583) ​ $ 4,900 Private Warrants 2 7,666,667 ​ $ 23,537 ​ $ (19,320) ​ $ 4,217 Total 19,333,303 ​ $ 50,020 ​ $ (40,903) ​ $ 9,117 ​

Common Stock Warrant Liabilitie

Common Stock Warrant Liabilities	12 Months Ended
	Dec. 31, 2022
Common Stock Warrant Liabilities
Common Stock Warrant Liabilities	Note 9 – Common Stock Warrant Liabilities As of December 31, 2022 and December 31, 2021, there were 11,666,636 publicly traded warrants (“Public Warrants”) and 7,666,667 private placement warrants (“Private Placement Warrants,” and together with the Public Warrants, “Warrants”) outstanding. Each whole Warrant entitles the holder thereof to purchase one share of Common Stock at a price of $11.50 per share, subject to customary adjustments. Only whole Warrants are exercisable. The Warrants became exercisable on January 7, 2022 and will expire on December 8, 2026. Redemption of Public Warrants when the price per share of Common Stock equals or exceeds $18.00 The Company may redeem all of the outstanding Public Warrants: ● in whole and not in part; ● upon at least 30 days ’ prior written notice; ● at a price of $0.01 per Public Warrant; and ● if the last sale price of the Company’s Common Stock equals or exceeds $18.00 per share, subject to customary adjustments, for any 20 trading days within a 30 -trading day period ending on the third trading day prior to the date on which notice of the redemption is given. Redemption of Public Warrants when the price per share of Common Stock equals or exceeds $10.00 The Company may redeem all of the outstanding Public Warrants: ● in whole and not in part; ● upon at least 30 days ’ prior written notice; ● at a price of $0.10 per Public Warrant, provided that holders will be able to exercise their Warrants on a cashless basis prior to redemption and receive a number of shares of Common Stock determined in part by the redemption date and the “fair market value” of the Common Stock; and ● if the last sale price of the Company’s Common Stock equals or exceeds $10.00 per share, subject to customary adjustments, on the trading day prior to the date on which notice of redemption is given. The “fair market value” of the Company’s Common Stock means the average reported last sale price of the Company’s Common Stock for the ten None of the Private Placement Warrants are redeemable by the Company so long as they are held by the initial purchasers of the Private Placement Warrants or their permitted transferees. The Warrant Liabilities were initially measured at fair value upon Closing of the Business Combination for $101,253 and subsequently re-measured on December 31, 2021 and December 31, 2022 for $50,020 and $9,117, respectively. The Public Warrants were allocated a portion of the proceeds from the issuance of the units of common stock and one-third warrants in DCRC’s initial public offering equal to their fair value. The Company recognized a gain in connection with changes in the fair value of warrant liabilities of $40,903 and $51,233 as of December 31, 2022 and 2021, respectively.

Mezzanine Equity

Mezzanine Equity	12 Months Ended
	Dec. 31, 2022
Mezzanine Equity
Mezzanine Equity	Note 10 – Mezzanine Equity In accordance with ASC 480, Legacy Solid Power’s Preferred Stock prior to the Business Combination was classified as mezzanine equity. Immediately prior to the Closing, Legacy Solid Power had 14,069,187 shares of Series A-1 Preferred Stock outstanding and 8,777,812 shares of Series B Preferred Stock outstanding. Legacy Solid Power issued the Series B Preferred Stock in May 2021 in exchange for $135,579 of cash and the conversion of the 2019 Note and the 2020 Notes. Prior to the Business Combination, the Preferred Stock had a redemption feature, at the option of the holders of a majority of the outstanding Preferred Stock, any time after April 30, 2031. The Preferred Stock was redeemable for the greater of its original issue price, plus all declared but unpaid dividends thereon, or fair value. Since the Preferred Stock had redemption provisions that were not solely within control of Legacy Solid Power, the Preferred Stock was classified prior to the Business Combination as mezzanine equity on Legacy Solid Power’s balance sheets. Immediately prior to the Business Combination, 14,069,187 shares of Series A-1 Preferred Stock and 8,777,812 shares of Series B Preferred Stock were converted to the equivalent number of shares of Legacy Solid Power common stock. At the Closing, those shares of Legacy Solid Power common stock were exchanged for Common Stock in accordance with the Exchange Ratio.

Stockholders' Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2022
Stockholders' Equity
Stockholders' Equity	Note 11 – Stockholders’ Equity Common Stock Stock options exercised for Common Stock are summarized in the table below: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ 2022 2021 2020 Stock options exercised ​ 8,428,524 ​ 1,160,930 ​ 1,097,370 ​ Cash received from options exercised under the Legacy Solid Power, Inc. 2014 Equity Incentive Plan (the “2014 Plan”) for the years ended December 31, 2022, 2021 and 2020 was $ 818 , $ 106 and $ 24 , respectively. During the years ended December 31, 2022, 2021 and 2020, restricted stock units (“RSUs”) vested for 29,108 , 0 , and 0 shares of Common Stock, respectively. Legacy Solid Power Warrants During 2015, Legacy Solid Power issued warrants to a third party to purchase 276,000 shares of Legacy Solid Power common stock at an exercise price of $ 0.00001088 per share, in conjunction with a licensing agreement. Management determined that equity classification is appropriate for these warrants. Legacy Solid Power recognized expense totaling $ 18 on the date of the grant that has been included as a component of Additional Paid In Capital within the consolidated statement of stockholders’ equity. During 2020, Legacy Solid Power issued additional warrants to purchase 45,730 shares of common stock at an exercise price of $ 0.53 per share. Legacy Solid Power recognized expense totaling $ 16 on the date of the grant. In May 2021, Legacy Solid Power issued warrants to purchase 1,755,557 shares of Legacy Solid Power common stock at an exercise price of $0.01 per share, in connection with the Series B Financing. These warrants were detachable from the Legacy Solid Power Series B Preferred Stock and in all cases would physically settle or net share settle. Therefore, Legacy Solid Power determined that these warrants represented equity in Legacy Solid Power. Prior to the Closing, all Legacy Solid Power warrants were either exercised for cash or net exercised and the holders thereof received shares of Legacy Solid Power common stock.

Stock Based Compensation

Stock Based Compensation	12 Months Ended
	Dec. 31, 2022
Stock Based Compensation
Stock Based Compensation	Note 12 – Stock Based Compensation 2014 Equity Incentive Plan and 2021 Equity Incentive Plan Options granted under the 2014 Plan generally had a ten-year term and vest as to 1/4 balance On December 8, 2021 and in connection with the Closing, the Company adopted the Solid Power, Inc. 2021 Equity Incentive Plan (the “2021 Plan”). The 2021 Plan originated with 18,900,000 shares of Common Stock available for issuance. Beginning on January 1, 2022, the number of shares of common stock available for issuance under the 2021 Plan shall increase each year by an amount equal to the lesser of (i) 18,900,000 shares of Common Stock (ii) five percent of the total number of shares of common stock outstanding on the last day of the immediately preceding fiscal year; or (iii) a number of shares of common stock determined by the administrator no later than the last day of the immediately preceding fiscal year. Awards may be issued in the form of stock options, stock appreciation rights, restricted stock, and restricted stock units. The Company believes that such awards better align the interests of its employees with those of its stockholders. Options granted under the 2021 Plan generally have a ten-year term and vest as to 1/4 Effective April 1, 2022, the Company began granting RSUs in accordance with the terms of the 2021 Plan. The grant date fair value of RSUs awarded are determined based on the Company’s closing common share price on the NASDAQ on the trading day preceding the grant date. RSU awards for employees generally vest 25% per year commencing on the first anniversary of the grant date. RSU awards upon initial service as a director vest in 12 equal quarterly installments. For initial service grants, vested RSUs are settled in common stock upon the earlier of the director no longer serving on the board of directors or the date the RSU has fully vested. Annual RSU awards to directors generally fully vest on the one-year anniversary of the grant date. Upon vesting, granted RSUs entitle the grantee to receive one share of common stock of the Company at no additional cost. Holders of unvested RSUs do not have voting or dividend rights. At December 31, 2022 and 2021 the Company had 24,766,176 and 34,407,949 shares of common stock underlying stock options outstanding under the 2014 Plan respectively. Upon the Closing, the 2014 Plan was terminated and no additional grants were made under the 2014 Plan. As of December 31, 2022, the 2021 Plan permitted the Company to grant up to 24,466,527 shares of common stock to its employees, directors, and consultants, as designated by the board of directors. ​ ​ ​ ​ ​ ​ ​ December 31, 2022 December 31, 2021 Option awards granted under 2021 Plan 1,730,564 — RSU awards granted under 2021 Plan ​ 1,292,429 ​ — ​ Compensation Expense for Stock Based Compensation The fair value of stock options and RSUs issued to employees and directors is recognized as compensation expense over the period of service that generally coincides with the vesting period of the award. When calculating the amount of annual compensation expense, the Company has elected not to estimate forfeitures and instead accounts for forfeitures as they occur. For the years ended December 31, 2022, 2021 and 2020 the Company recognized compensation costs totaling: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ 2022 2021 2020 Equity-based compensation costs related to RSUs ​ $ 1,567 ​ $ — ​ $ — Equity-based compensation costs related to stock options ​ 7,076 ​ 2,714 ​ 182 Equity-based compensation costs related to ESPP ​ 29 ​ — ​ — Total equity-based compensation costs ​ $ 8,672 ​ $ 2,714 ​ $ 182 Future compensation costs related to unvested options ​ $ 19,322 ​ $ 23,307 ​ $ 593 ​ The fair value of stock options and other equity-based compensation issued to employees is recognized as compensation expense over the period of service that generally coincides with the vesting period of the award. The Company allocated compensation ratably across Operating Expenses within the following financial statement lines: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ 2022 2021 2020 Direct Costs ​ $ 1,580 ​ $ 332 ​ $ 22 Research and Development ​ ​ 4,474 ​ ​ 1,698 ​ ​ 115 Sales and Marketing ​ ​ 493 ​ ​ 308 ​ ​ 23 General and Administrative ​ ​ 2,125 ​ ​ 376 ​ ​ 22 Total equity-based compensation cost ​ $ 8,672 ​ $ 2,714 ​ $ 182 ​ Stock Options The fair value for purposes of determining the compensation cost of each option award is estimated on the date of grant using a Black-Scholes option valuation model that uses the weighted-average assumptions noted in the following table. Expected volatilities are based on historical volatility of comparable companies. The Company uses historical data to estimate option exercise and employee termination within the valuation model. The risk-free rate for periods within the contractual life of the option is based on the U.S. Treasury yield curve in effect at the time of grant. The fair value of each option grant during the years ended December 31, 2022, 2021 and 2020 was estimated on the grant date using the Black-Scholes option pricing model with the following weighted-average assumptions used: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2022 2021 2020 Approximate risk-free rate ​ 2.84 % ​ 1.04 % ​ 1.29 % Volatility ​ 44.69 % ​ 41.45 % ​ 43.92 % Average expected life (years) ​ 6 years ​ 6 years ​ 6 years Dividend yield ​ 0 % ​ 0 % ​ 0 % Weighted-average grant date fair value ​ $ 7.26 ​ $ 5.10 ​ $ 0.84 ​ Estimated fair value of total options granted ​ $ 5,659 ​ $ 25,353 ​ $ 246 ​ ​ When calculating the amount of annual compensation expense, the Company has elected not to estimate forfeitures and instead accounts for forfeitures as they occur. A summary of option activity under the 2014 Plan and 2021 Plan for the years ended December 31, 2022, 2021, and 2020 is presented below: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted-average ​ ​ ​ ​ ​ ​ ​ Remaining ​ ​ Number of ​ Weighted-average ​ Contractual Term Options Shares Exercise Price (in years) Outstanding at January 1, 2020 23,020,981 ​ $ 0.06 7.06 Granted 1,719,754 ​ $ 0.16 Exercised (1,097,370) ​ $ 0.02 Forfeited or expired (167,381) ​ $ 0.15 Outstanding at December 31, 2020 23,475,984 ​ $ 0.06 6.53 ​ ​ ​ ​ ​ ​ ​ ​ Outstanding at January 1, 2021 ​ 23,475,984 ​ $ 0.06 ​ 6.53 Granted 12,285,359 ​ $ 5.10 ​ Exercised ​ (1,160,930) ​ $ 0.09 ​ ​ Forfeited or expired (192,464) ​ $ 0.84 ​ Outstanding at December 31, 2021 ​ 34,407,949 ​ $ 1.86 ​ 6.98 ​ ​ ​ ​ ​ ​ ​ ​ Outstanding at January 1, 2022 ​ 34,407,949 ​ $ 1.86 ​ 6.98 Granted ​ 1,730,564 ​ $ 7.19 ​ ​ Exercised ​ (8,428,524) ​ $ 0.10 ​ ​ Forfeited or expired ​ (1,711,817) ​ $ 4.64 ​ ​ Outstanding at December 31, 2022 ​ 25,998,172 ​ $ 2.60 ​ 6.31 ​ ​ ​ ​ ​ ​ ​ ​ Exercisable at December 31, 2020 ​ 18,023,695 ​ $ 0.04 ​ 5.96 Exercisable at December 31, 2021 ​ 19,603,474 ​ $ 0.05 ​ 5.21 Exercisable at December 31, 2022 ​ 18,202,064 ​ $ 1.19 ​ 5.14 ​ Cash received from options exercised under the 2014 Plan for December 31, 2022, 2021 and 2020 was $818, $106 and $23, respectively. The aggregate intrinsic value of exercisable options at December 31, 2022 was $35,058. The aggregate intrinsic value of exercised options at December 31, 2022 was $63,287. Restricted Stock Units The following table summarizes non-vested RSUs at December 31, 2022 and the changes for the period ended December 31, 2022: ​ ​ ​ ​ ​ ​ ​ ​ Number of Weighted-average ​ ​ Shares ​ Grant Date Fair Value Balance at January 1, 2022 — ​ Granted 1,292,429 ​ $ 7.11 Vested (29,108) ​ $ 7.26 Forfeited (205,341) ​ $ 7.33 Outstanding at December 31, 2022 1,057,980 ​ $ 7.06 ​ As of December 31, 2022 unrecognized compensation costs related to restricted stock units was $6,144 and is expected to be recognized over a weighted average period of 2.97 years. The vested RSUs had no intrinsic value as of December 31, 2022. 2021 Employee Stock Purchase Plan The 2021 Employee Stock Purchase Plan (“2021 ESPP”) originated with 3,778,000 shares of Common Stock available for issuance. As of December 31, 2021, 3,778,000 shares remained available for issuance. Beginning on January 1, 2022, the number of shares of Common Stock available for issuance under the 2021 ESPP shall increase by an amount equal to the lesser of (i) 3,778,000 shares of Common Stock (ii) one percent (1%) of the total number of shares of Common Stock outstanding on the last day of the immediately preceding fiscal year or (iii) a number of shares of Common Stock determined by the Administrator no later than the last day of the immediately preceding fiscal year. As of December 31, 2022 5,463,579 shares remained available for issuance. As of December 31, 2022 the 2021 ESPP permitted the Company to issue up to 5,463,579 shares of common stock. The Company recorded $29 of expense related to the 2021 ESPP in the year ended December 31, 2022. No shares have been purchased under the ESPP as of December 31, 2022. As of December 31, 2022, there was $58 of unrecognized stock-based compensation expense related to the ESPP that is expected to be recognized by the end of second quarter of 2023. The 2021 ESPP is intended to qualify as an “employee stock purchase plan” under Section 423 of the Internal Revenue Code. Substantially all employees are eligible to participate and, through payroll deductions, can purchase shares on dates determined by the administrator. However, with respect to the Section 423 Component, an employee may not be granted rights to purchase stock under the ESPP if the employee, immediately after the grant, would own (directly or through attribution) stock possessing 5% or more of the total combined voting power or value of all classes of the Company’s Common Stock. The purchase price per share sold pursuant to the 2021 ESPP will be the lower of (i) 85% of the fair market value of Common Stock on the enrollment or (ii) 85% of the fair market value on the exercise date. Each offering period will span up to six months. Purchases may be up to 15% of qualified compensation, with an annual limit of $25,000.

Earnings (Loss) Per Share

Earnings (Loss) Per Share	12 Months Ended
	Dec. 31, 2022
Earnings (Loss) Per Share
Earnings (Loss) Per Share	Note 13 – Earnings (Loss) Per Share The table below reconciles basic weighted average common shares outstanding to diluted weighted average shares outstanding for December 31, 2022, 2021 and 2020. Basic earnings per share is based on the weighted average number of common shares outstanding for the period. Basic earnings per share represents net earnings or loss attributable to Common Stock divided by the basic weighted average number of common shares outstanding during the period. Diluted earnings per share also includes the dilutive effect of additional potential common shares issuable from stock-based awards and are determined using the treasury stock method. Diluted earnings per share represents net earnings divided by diluted weighted average number of common shares, which includes the average dilutive effect of all potentially dilutive securities that are outstanding during the period. The unvested stock awards, warrants, and options are included in the number of shares outstanding for diluted earnings per share calculations, unless a net loss is reported, in which situation unvested stock awards, warrants, and options are excluded from the number of shares outstanding for diluted earnings per share calculations. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Years Ended December 31, ​ 2022 ​ 2021 ​ 2020 Net income (loss) attributable to common stockholders ​ $ (9,555) ​ $ 12,656 ​ $ (14,375) Weighted average shares outstanding – basic ​ ​ 174,374,386 ​ ​ 95,477,472 ​ ​ 69,228,444 Weighted average shares outstanding – diluted ​ 174,374,386 ​ 114,910,129 ​ ​ 69,228,444 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Basic earnings (loss) per share ​ $ (0.05) ​ $ 0.13 ​ $ (0.21) Diluted earnings (loss) per share ​ $ (0.05) ​ $ 0.11 ​ $ (0.21) ​ Due to the net loss to common stockholders in 2022 and 2020 presented above, diluted loss per share was computed without consideration of potentially dilutive instruments as their inclusion would have been anti-dilutive. Warrants outstanding in 2022 and 2021 were not included in the computation of diluted earnings per share because the warrant’s exercise price for the period was greater than the average market price of the common shares. As of December 31, 2022, 2021 and 2020, potentially dilutive securities excluded from the diluted earnings (loss) per share calculation are as follows (in shares): ​ ​ ​ ​ ​ ​ ​ ​ ​ 2022 2021 2020 Common Stock Warrants 19,333,303 19,333,303 ​ 1,023,745 2014 & 2021 Equity Incentive Plan - Stock Options 26,328,279 — ​ 23,476,182 2021 Equity Incentive Plan - Restricted Stock Units 710,385 — ​ — 2021 Employee Stock Purchase Plan ​ 26,589 ​ — ​ — Contingently Issuable Common Stock ​ 5,339 ​ — ​ — Total potentially dilutive securities ​ 46,403,895 ​ 19,333,303 ​ 24,499,927 ​

Leases

Leases	12 Months Ended
	Dec. 31, 2022
Leases
Leases	Note 14 – Leases The Company leases its two facilities and certain equipment. Fixed rent generally escalates each year, and the Company is responsible for a portion of the landlords’ operating expenses such as property tax, insurance and common area maintenance. The Company’s facility in Louisville, Colorado is under a noncancelable operating lease with a maturity date in September 2029. In 2022, the Company amended the lease to incorporate a prior subleased space into the base lease and extend the term of the lease. The Company has the right to renew this lease for an additional five-year period. On September 1, 2021, the Company entered into an industrial operating lease agreement for its facility in Thornton, Colorado, with the initial term through March 31, 2029. Under this operating lease, the Company has one option to renew for five years, which has been included in the calculation of lease liabilities and right-of-use assets at the adoption date of the lease accounting standard on January 1, 2022, as the exercise of the option was reasonably certain. As the renewal rent has not been negotiated, the Company used an estimated rent rate which approximated the fair market rent at adoption of ASC 842 on January 1, 2022 for the extension period. The Company has certain equipment leases classified as finance leases as of December 31, 2022. The Company’s leases do not have any contingent rent payments and do not contain residual value guarantees. The components of lease expense are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2022 December 31, 2021 Finance lease costs: ​ ​ Amortization of right-of-use assets ​ $ 92 ​ $ — Interest on lease liabilities ​ 28 ​ — Operating lease costs ​ 850 ​ — Total lease expense ​ $ 970 ​ $ — ​ The components of cash flow information related to leases are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2022 December 31, 2021 Operating outgoing cash flows – finance lease ​ $ 24 ​ $ — Financing outgoing cash flows – finance lease ​ 142 ​ — Operating outgoing cash flows – operating lease ​ 568 ​ — Right-of-use assets obtained in exchange for new finance lease liabilities ​ 1,014 ​ — Right-of-use assets obtained in exchange for new operating lease liabilities ​ 8,947 ​ — ​ ​ ​ ​ ​ ​ December 31, 2022 Finance lease ​ Weighted-average remaining lease term – finance lease (in years) 3.37 ​ Weighted-average discount rate – finance lease 5.9 % Operating lease ​ Weighted-average remaining lease term – operating lease (in years) 10.18 ​ Weighted-average discount rate – operating lease 6.9 % ​ As of December 31, 2022, future minimum payments during the next five years and thereafter are as follows: ​ ​ ​ ​ ​ ​ ​ Fiscal year Finance Lease Operating Lease 2023 ​ $ 315 ​ $ 1,138 2024 ​ ​ 315 ​ ​ 1,173 2025 ​ ​ 192 ​ ​ 1,210 2026 ​ ​ 85 ​ ​ 1,248 2027 ​ ​ 37 ​ ​ 1,288 Thereafter ​ ​ 16 ​ ​ 6,571 Total ​ ​ 960 ​ ​ 12,628 Less present value discount ​ ​ 85 ​ ​ 3,457 Total lease liabilities ​ $ 875 ​ $ 9,171 ​

Related Party Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2022
Related Party Transactions
Related Party Transactions	Note 15 – Related Party Transactions During 2020, the Company entered into a subcontractor agreement with Roccor, LLC, which was a related party until October 30, 2020. Under the subcontractor agreement, the Company provided technical support to Roccor on a government research contract. The total value of the subcontract is $331 to the Company. The period of performance commenced during 2020 and extended to late 2021. Related party revenue from Roccor was $163 for the year ended December 31, 2020. During 2022, the Company entered into a collaborative arrangement with BMW of North America, LLC (“BMW”). Pursuant to the terms of the agreement, the Company granted BMW a research and development-only license to certain of the Company’s intellectual property relating to solid-state battery cell manufacturing (the “R&D License”). The R&D License allows, among other things, BMW to install a solid-state prototype cell manufacturing line based upon the Company’s proprietary information. The R&D License is limited to BMW’s research and development activities and may not be used for commercial battery cell production. The Company and BMW also agreed to negotiate a non-exclusive short-term electrolyte supply agreement for the Company to supply BMW with electrolyte material for use in BMW’s cell manufacturing, which is expected to commence in 2024 following commissioning of BMW’s solid-state protype cell manufacturing line. Pursuant to the agreement, prior to installation of BMW’s anticipated prototype cell manufacturing line, the Company and BMW have agreed to undertake development and manufacturing activities jointly at the Company’s facilities. Any intellectual property developed jointly by the Company and BMW at the Company’s facilities will be solely owned by the Company (“Joint Onsite Foreground IP”). To the extent intellectual property is jointly conceived but not considered Joint Onsite Foreground IP, the Company and BMW will jointly own such intellectual property. Each party will solely own intellectual property developed solely by such party. The Company and BMW will each have the right to utilize the other party’s technical improvements for research and development purposes only. Subject to certain limitations, the Company has the right to cause BMW to license BMW’s technical improvements to the Company for commercial purposes. In consideration of the R&D License and additional development activities contemplated by the agreement BMW will pay the Company $20 million between December 2022 and June 2024, subject to the Company achieving certain milestones. For the year ended December 31, 2022, the Company has recognized $2 million of revenue from BMW and recorded $4 million of deferred revenue related to cash paid from BMW in advance of services provided. Unrelated to the terms under the R&D License agreement the Company received $375 from BMW in exchange for initial prototype cells. ​

Retirement plans

Retirement plans	12 Months Ended
	Dec. 31, 2022
Retirement Plans
Retirement Plans	Note 16 – Retirement Plans ​ The Company sponsors a 401(k) plan for all employees. The plan provides for the Company to make a discretionary matching contribution. Contributions to the plan totaled $802, $352 and $226 for the years ended December 31, 2022, 2021 and 2020, respectively.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2022
Income Taxes
Income Taxes	Note 17 – Income Taxes The Company provides deferred U.S. federal, state, or foreign income tax benefits for all of the periods presented. The Company has also provided a valuation allowance on the net deferred tax asset because of uncertainty regarding its realizability. Realization of deferred tax assets is dependent on generating sufficient taxable income prior to the expiration of loss carryforwards. Deferred tax assets and liabilities arise primarily from net operating loss carryforwards and temporary differences arising from the amortization of intangible assets, depreciation on property and equipment, and various accrued liabilities. Income taxes included in the Consolidated Statements of Operations for the years ended December 31, 2022, 2021 and 2020 are detailed below: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the Years Ended December 31, ​ 2022 2021 2020 Deferred income tax (benefit) expense: ​ ​ ​ ​ ​ Federal ​ $ (195) ​ $ (22) ​ $ 96 State ​ ​ (32) ​ (3) ​ 22 Total income tax (benefit) expense ​ $ (227) ​ $ (25) ​ $ 118 ​ The tables below represent a reconciliation of the statutory federal income tax expense to income tax: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ 2022 2021 2020 Income tax expense at the federal statutory rate ​ 21.00 % 21.00 % 21.00 % State income benefits ​ 13.07 % (5.97) % 2.96 % Permanent Differences ​ (3.14) % 0.25 % 1.08 % Permanent Differences – Related to Convertible Debt ​ 0.00 % 0.31 % (5.04) % Permanent Differences – Fair Value Adjustments– Warrant Liability ​ 66.21 % (56.44) % 0.00 % Permanent Differences – Fair Value Adjustments– Marketable Securities ​ (5.13) % 0.00 % 0.00 % Prior year provision to return ​ 0.03 % (0.03) % (0.03) % Net change in valuation allowance ​ (104.28) % 40.73 % (20.81) % Research and Development ​ 13.65 % 0.00 % 0.00 % Other ​ 0.33 % 0.01 % 0.00 % Total income tax (benefit) ​ 1.75 % (0.14) % (0.84) % ​ For the years ended December 31, 2022, 2021 and 2020, the effective tax rate was approximately 1.75%, (0.14%) and (0.84%), respectively. Differences between the statutory rate and the Company’s effective tax rate resulted from changes in valuation allowance and permanent differences for tax purposes in the treatment of certain nondeductible expenses. The tax effects of temporary differences that give rise to significant portions of the deferred income tax assets and liabilities are presented below: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ 2022 2021 Deferred tax assets: ​ ​ ​ ​ Net operating loss ​ $ 17,962 ​ $ 15,591 R&D Credit ​ ​ 1,908 ​ ​ — Stock compensation ​ ​ 1,991 ​ ​ 417 Section 174 Capitalization ​ ​ 5,731 ​ ​ — ROU Lease Liability ​ ​ 2,459 ​ ​ — Other ​ 748 ​ 49 Total income tax expense (benefit) ​ 30,799 ​ 16,057 Valuation allowance ​ (28,030) ​ (14,536) Net deferred tax assets: ​ 2,769 ​ 1,521 Deferred tax liabilities: ​ ​ Intangibles (non-goodwill) ​ $ (1) ​ $ — Property and equipment ​ (652) ​ (1,747) ROU Asset ​ ​ (2,116) ​ ​ — Total deferred tax liabilities ​ (2,769) ​ (1,747) Total net deferred tax liability ​ $ — ​ $ (226) ​ The ultimate realization of deferred tax assets is dependent upon the existence, or generation, of taxable income in the periods when those temporary differences and net operating loss carryovers are deductible. Management considers the scheduled reversal of deferred tax liabilities, taxes paid in carryover years, projected future taxable income, available tax planning strategies, and other factors in making this assessment. Based on available evidence, management does not believe it is more likely than not that all of the deferred tax assets will be realized. Accordingly, the Company has established a valuation allowance equal to the net realizable deferred tax assets. The valuation allowance increased by $13,494 in 2022. At December 31, 2022, 2021 and 2020, the Company had total domestic Federal net operating loss carryovers of approximately $73,367, $63,391 and $29,836, respectively. Federal net operating losses generated on or prior to December 31, 2017 expire in 2037. Federal net operating losses generated on or after January 1, 2018 have an indefinite carryforward and are only available to offset 80% taxable income beginning in 2021. The determination of state net operating loss carryforwards is dependent upon apportionment percentages and state laws that can change from year to year and that can thereby impact the amount of such carryforwards. The majority of the state net operating losses have an indefinite carryforward. Accounting for uncertainty in income taxes is based on a recognition threshold and measurement attribute for the Consolidated Financial Statements recognition and measurement of a tax position taken or expected to be taken in a tax return. The Company recognizes in its Consolidated Financial Statements only those tax positions that are more-likely-than-not to be sustained as of the adoption date, based on the technical merits of the position. Each year the Company performs a comprehensive review of its material tax positions. The Company’s policy is to recognize interest and penalties related to uncertain tax benefits in income tax expense. As the Company had no uncertain tax benefits before the year ending December 31, 2022, there is no accrual of interest or penalties related to uncertain tax positions. The following table summarizes the Company’s unrecognized tax benefits: ​ ​ ​ ​ ​ ​ December 31, 2022 Balance, beginning of year ​ $ — Gross increases related to prior period tax position ​ — Gross increases related to current period tax position ​ 636 Gross decreases related to prior period tax position ​ — Balance, end of year ​ $ 636 ​ Included in the balance of unrecognized tax benefits at December 31, 2022, are potential benefits of $636 that if recognized would affect the effective tax rate. The 2018 through 2021 tax years remain open to examination by the Internal Revenue Service and, with few exceptions, various other state tax agencies. These taxing authorities have the authority to examine those tax years until the applicable statutes of limitations expire.

Contingencies

Contingencies	12 Months Ended
	Dec. 31, 2022
Contingencies
Contingencies	Note 18 – Contingencies In the normal course of business, the Company may be party to litigation from time to time. The Company maintains insurance to cover certain actions and believes that resolution of such litigation will not have a material adverse effect on the Company. DCRC, the predecessor to the Company, received a demand letter dated August 31, 2021 from counsel purporting to represent a stockholder of DCRC alleging that the proposed vote on the Authorized Share Charter Proposal (“Proposal”) for the proposed business combination with Legacy Solid Power violated Section 242(b)(2) of the Delaware General Corporation law and demanded that DCRC provide DCRC’s Class A stockholders with a separate class vote on the Proposal. DCRC subsequently provided for the Class A stockholders to have a separate class vote on the Proposal share increase. The Proposal was approved and the Business Combination closed. The counsel who issued this demand letter made a fee demand (the “Fee Demand”) for prompting the change in the Proposal. The Company accrued a liability of $500 on its Consolidated Balance Sheets as of December 31, 2021 in anticipation of settling the Fee Demand. On March 10, 2022, the Company settled the Fee Demand for an amount that is materially consistent with our accrual. Based on cash on hand at December 31, 2022, management believes the Company has sufficient capital to execute its strategic plan and fund operations through at least the next 12 months from the date these Consolidated Financial Statements are issued.

Significant Accounting Polici_2

Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2022
Significant Accounting Policies
Basis of Presentation and Principles of Consolidation	Basis of Presentation and Principles of Consolidation The Consolidated Financial Statements of the Company have been prepared on the basis of generally accepted accounting principles in the United States (“GAAP”). The preparation of Consolidated Financial Statements in conformity with GAAP requires management to make estimates and assumptions that affect amounts reported in the Consolidated Financial Statements. Actual results could differ from those estimates. All amounts presented in the footnotes are in thousands, except share and per share amounts. Pursuant to the Business Combination Agreement, the merger between Merger Sub and Legacy Solid Power was accounted for as a reverse recapitalization in accordance with GAAP (the “Reverse Recapitalization”). Under this method of accounting, DCRC was treated as the “acquired” company and Legacy Solid Power is treated as the acquirer for financial reporting purposes. Accordingly, for accounting purposes, the Reverse Recapitalization was treated as the equivalent of Legacy Solid Power issuing stock for the net assets of DCRC, accompanied by a recapitalization. The net assets of DCRC are stated at historical cost, with no goodwill or other intangible assets recorded. The consolidated assets, liabilities, and results of operations prior to the Reverse Recapitalization are those of Legacy Solid Power. The shares and corresponding capital amounts and losses per share, prior to the Business Combination, have been retroactively restated based on the Exchange Ratio (defined below). The Consolidated Financial Statements include accounts of the Company and its wholly owned subsidiary, Solid Power Operating, Inc. All intercompany balances and transactions have been eliminated in consolidation. The accompanying Consolidated Financial Statements have been prepared assuming that the Company will continue as a going concern.
Segment Reporting	Segment Reporting The Company’s Chief Operating Decision Maker (“CODM”) is its Chief Executive Officer. The Company has determined that it operates in one operating segment and one reportable segment, as the CODM reviews financial information presented as a single entity for purposes of making operating decisions, allocating resources, and evaluating financial performance.
Use of Estimates	Use of Estimates The preparation of financial statements in accordance with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, and contingencies at the date of the financial statements as well as reported amounts of revenues and expenses during the reporting periods. Estimates made by the Company include, but are not limited to, those related to the valuation of common stock prior to the Business Combination, valuation of stock warrants, and useful lives of long-term assets, among others. The Company bases these estimates on historical experience and other assumptions that it believes are reasonable under the circumstances.
Cash and Cash Equivalents	Cash and Cash Equivalents The Company considers all highly liquid investments with an original maturity of three months or less when purchased to be cash equivalents. As of December 31, 2022 and periodically throughout the year, the Company’s cash accounts exceeded federally insured limits.
Marketable Securities	Marketable Securities The Company’s investment policy is consistent with the definition of available-for-sale securities. The Company does not buy and hold securities principally for the purpose of selling them in the near future. The Company’s policy is focused on the preservation of capital, liquidity, and return. From time to time, the Company may sell certain securities, but the objectives are not to generate profits on short-term differences in price. These securities are carried at estimated fair value with unrealized holding gains and losses included in other comprehensive loss in stockholders’ deficit until realized. Gains and losses on marketable security transactions are reported on the specific-identification method. Dividend and interest income are recognized when earned.
Contract Receivables	Contract Receivables Contract receivables consist of amounts due from government entities and commercial contractors. Management considers all contract receivables collectible, and therefore, an allowance for doubtful accounts has not been recorded as of December 31, 2022 and 2021. Included within contract receivables are amounts for work performed but not billed as of December 31, 2022 and 2021, shown below. ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2022 December 31, 2021 Contract receivables not billed ​ $ 1,083 ​ $ 310 ​
Credit Risk and Major Customers	Credit Risk and Major Customers Financial instruments that potentially subject the Company to credit risk consist principally of cash and cash equivalents, marketable securities, and long-term investments. The Company seeks to mitigate its credit risk with respect to cash and cash equivalents, marketable securities, and long-term investments by making deposits with several large, reputable financial institutions and investing in high credit rated instruments. The Company grants credit in the normal course of business to government entities and commercial contractors in the United States. The Company periodically performs credit analyses and monitors the financial condition of its customers to reduce credit risk. The Company performs ongoing credit evaluations of its customers, but generally does not require collateral to support contract receivables. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the Years Ended December 31, ​ 2022 2021 2020 Revenue Concentration ​ ​ ​ ​ Number of Customers ​ 4 4 3 ​ Related Total Revenue Percentage 82 % 87 % 81 % Contract Receivable Concentration ​ Number of Customers 2 2 1 ​ Related Contract Receivables Percentage 40 % 58 % 18 % ​
Prepaid Expenses and Other Current Assets	Prepaid Expenses and Other Current Assets Prepaid expenses and other current assets consist primarily of security deposits, prepaid Directors and Officers insurance and other minor miscellaneous expenses paid in advance.
Property and Equipment	Property and Equipment Property and equipment are recorded at cost. The Company capitalizes property and equipment with useful lives exceeding one year. Assets are depreciated over their estimated useful lives. The straight-line method is used for computing depreciation and amortization. Depreciation and amortization expenses are recorded within the Direct costs and Research and development line items in the Consolidated Statements of Operations. Cost of maintenance and repairs are charged to expense when incurred. Construction in progress related to specialized equipment will be reclassified as Property and equipment and depreciated, once placed in service. ​ ​ ​ ​ ​ Depreciable Life - Years Commercial production equipment ​ 5 years Laboratory equipment ​ 5 years Furniture and Computer Equipment 3-7 years Leasehold improvements Lesser of asset life or lease term ​
Long-Term Investments	Long-Term Investments The Company considers all investments with an original maturity of twelve months or more when purchased to be long-term investments.
Intangible Assets	Intangible Assets Intangible assets consist of licenses and costs incurred for pending patents and pending trademarks. Licenses consist of rights to use patents and are amortized over their estimated useful life of three
Deferred Rent	Deferred Rent Prior to the adoption of ASU No. 2016-02, Leases (Topic 842) on January 1, 2022, the Company had entered into operating lease agreements for each of its two facilities, each of which contain provisions for future rent increases or periods in which rent payments are reduced. The Company records monthly rent expense equal to the total of the payments due over the lease term, divided by the number of months of the lease term. The difference between rent expense recorded and the amount paid is credited or charged to deferred rent, which is reflected in Other Long-term Liabilities in the accompanying Consolidated Balance Sheets. Deferred rent also includes the unamortized portion of landlord-financed tenant improvement allowances, which are amortized on a straight-line basis over the lease term as a reduction in rent expense.
Leases	Leases The Company accounts for its leases under ASU No. 2016-02, Leases (Topic 842). Under this guidance, the Company classifies contracts meeting the definition of a lease as operating or financing leases, and leases are recorded on the condensed consolidated balance sheet as both a right-of-use asset and lease liability, calculated by discounting fixed lease payments over the lease term at the rate implicit in the lease or the Company’s incremental borrowing rate. Lease liabilities are increased by interest and reduced by payments each period, and the right-of-use asset is amortized over the lease term. For operating leases, interest on the lease liability and the amortization of the right-of-use asset result in straight-line rent expense over the lease term. For finance leases, interest on the lease liability and the amortization of the right-of-use asset results in front-loaded expense over the lease term. Variable lease expenses, including common maintenance fees, insurance and property tax, are recorded when incurred. In calculating the right-of-use asset and lease liability, the Company elects to combine lease and non-lease components for all classes of assets. The Company excludes short-term leases having initial terms of 12 months or less as an accounting policy election, and instead recognizes rent expense on a straight-line basis over the lease term.
Stock-based Compensation	Stock-based Compensation The Company recognizes expenses for employee services received in exchange for stock-based compensation based on the grant date fair value of the awards. The determination of the estimated fair value of stock-based payment awards on the date of grant using the Black-Scholes option-pricing model is affected by the Company’s stock price, as well as assumptions regarding risk-free rate, dividend yield, and the historical volatility of comparable entities. Stock-based compensation is recorded as an expense only for those awards that are expected to vest. Compensation cost is recognized on a straight-line basis over the requisite vesting service period and is allocated ratably within Operating Expenses in the Consolidated Statements of Operations.
Revenue	Revenue The Company records the elements of its joint development agreements that represent joint operating activities in accordance with Accounting Standards Codification (ASC) Topic 808, Collaborative Arrangements. Accordingly, the elements of the joint development agreements that represent activities in which both parties are active participants and to which both parties are exposed to the significant risks and rewards that are dependent on the commercial success of the activities are recorded as collaborative arrangements. The Company considers the guidance in ASC 606-10-15, Revenue from Contracts with Customers – Scope and Scope Exceptions, in determining the appropriate treatment for the transactions between the Company and its partners and the transactions between the Company and third parties. Generally, the classification of transactions under the joint development agreements is determined based on the nature and contractual terms of the arrangement along with the nature of the operations of the participants. The Company recognizes collaborative revenue from cost contracts on the basis of costs incurred during the period and cost plus fixed-fee contracts on the basis of costs incurred during the period plus the fee earned. Contract costs include all direct labor, subcontract, material, and indirect costs related to the contract performance that are allowable under contract provisions. Unbilled receivables are included in contract receivables and represent revenue recognized for which billings have not yet been presented to customers. Deferred revenue represents billings in advance of revenue recognized. Deferred revenue as of December 31, 2022 and 2021 was $4,050 and $500, respectively.
Beneficial Conversion Feature and Embedded Derivatives	Beneficial Conversion Feature and Embedded Derivatives The beneficial conversion feature (the “BCF”) of a convertible note is normally characterized as the convertible portion or feature of certain notes payable that provide a rate of conversion that is below market value or in-the-money when issued. For convertible debt where the rate of conversion is below market value, the Company records a BCF and related debt discount. When Legacy Solid Power recorded a BCF, the intrinsic value of the BCF was recorded in equity to Additional paid-in capital and the difference between the debt proceeds and the BCF was a debt discount against the face amount of the respective debt instrument and amortized to interest expense over the life of the debt. A separate embedded derivative was recognized as a derivative liability that was subsequently adjusted to fair value at each Consolidated Balance Sheet date. Embedded derivatives that are required to be bifurcated from the underlying debt instrument (i.e., host) are accounted for and valued as separate financial instruments. Legacy Solid Power evaluated the terms and features of its 2020 convertible promissory notes (as defined below) and identified embedded derivatives requiring bifurcation and accounting at fair value, using the valuation techniques mentioned in the Fair Value Measurements section of this Note, because the economic and contractual characteristics of the embedded derivatives met the criteria for bifurcation and separate accounting due to the instruments containing mandatory redemption features that were not clearly and closely related to the debt host instrument.
Warrant Liabilities	Warrant Liabilities The Company accounts for warrants as liability-classified instruments based on an assessment of the warrant’s specific terms and applicable authoritative guidance in ASC 480 and ASC 815. Warrants recorded as liabilities are recorded at their fair value, within Warrant Liabilities on the Consolidated Balance Sheets and are remeasured on each reporting date with changes recorded in Change in fair value of warrant liabilities on the Company’s Consolidated Statements of Operations.
Fair Value Measurements	Fair Value Measurements The Company applies fair value accounting for selected financial assets and liabilities measured on a recurring and nonrecurring basis. Fair value is defined as an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or a liability. The accounting guidance ASC Topic 820 Fair Value Measurement established a fair value hierarchy based on three levels of inputs, of which the first two are considered observable and the last unobservable, used to determine the fair value of its financial instruments. A financial instrument’s level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement. Level 1 – inputs include quoted market prices in an active market for identical assets or liabilities. Level 2 – inputs are market data, other than Level 1, that are observable either directly or indirectly. Level 2 inputs include quoted market prices for similar assets or liabilities, quoted market prices in an inactive market, and other observable information that can be corroborated by market data. Level 3 – inputs are unobservable and corroborated by little or no market data.
Research and Development	Research and Development Research and development expenditures of approximately $38,592, $17,102 and $9,594 in 2022, 2021 and 2020, respectively, were charged to expense as incurred.
Income Taxes	Income Taxes The Company recognizes deferred tax liabilities and assets for the expected future tax consequences of events that have been included in the Consolidated Financial Statements or tax returns. Deferred tax liabilities and assets are determined based on the differences between the Consolidated Financial Statements and tax basis of assets and liabilities using the enacted tax rates in effect for the year in which the differences are expected to reverse. The measurement of deferred tax assets is reduced, if necessary, by the amount of any uncertain tax positions or tax benefits that are not expected to be realized based on available evidence. The Company records deferred tax assets and associated valuation allowances, when appropriate, to reflect amounts more likely than not to be realized based upon Company analysis. The Company’s temporary differences result primarily from capitalization of certain qualifying research and development expenses, accruals and reserves, depreciation of property and equipment, stock compensation expense, capitalization of operating or financing leases, and net operating loss carryovers. The Company accounts for any uncertainty in income taxes by recognizing the tax benefit from an uncertain tax position only if it is more likely than not that the tax position will be sustained on examination by the taxing authorities, based on the technical merits of the position. The Company measures the tax benefits recognized in the Consolidated Financial Statements from such a position based on the largest benefit that has a greater than 50 percent likelihood of being realized upon ultimate resolution. Interest and penalties associated with tax positions are recorded in the period assessed as General and administrative on the Consolidated Statement of Operations. No interest or penalties have been assessed during the years ended December 31, 2022, 2021 and 2020.
Net Earnings (Loss) per Share of Common Stock	Net Earnings (Loss) per Share of Common Stock Basic net earnings (loss) per share is computed by dividing the net loss by the weighted-average number of shares of common stock outstanding during the period. Diluted earnings per share adjusts basic earnings per share for the potentially dilutive impact of stock options and warrants. The Company reported a net loss in 2022 and 2020. As such all potentially dilutive securities including options and warrants, are antidilutive and accordingly, basic net loss per share equals diluted loss per share. As the Company reported net income in 2021, diluted earnings per share reflected any dilutive effect of stock options and warrants.
Mezzanine Equity	Mezzanine Equity In accordance with ASC 480, Legacy Solid Power’s Series A-1 Preferred Stock and Series B Preferred Stock (collectively, “Preferred Stock”) prior to the Business Combination were classified as mezzanine equity as the Preferred Stock included redemption features that were not solely within control of Legacy Solid Power. Immediately prior to the consummation of the Business Combination, 14,069,187 shares of Legacy Solid Power Series A-1 Preferred Stock and 8,777,812 shares of Legacy Solid Power Series B Preferred Stock, which represented all of the then-outstanding shares of Preferred Stock, converted to Legacy Solid Power common stock on a one-to-one basis. At the Closing (as defined below), all shares of Legacy Solid Power common stock were exchanged for shares of Solid Power Common Stock based on the Exchange Ratio.
Recent Accounting Pronouncements	Recent Accounting Pronouncements Leases In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842), followed by other related ASUs that provided targeted improvements and additional practical expedient options. On January 1, 2022, the Company adopted the standards under Topic 842 using the modified retrospective method and elected a number of the practical expedients in its implementation of Topic 842. The key change that affected the Company relates to accounting for operating leases for which it is the lessee that were historically off-balance sheet. The impact of adopting the standards resulted in the recognition of a right-of-use asset of $7,853 and lease liability of $8,246 on the Company’s condensed consolidated balance sheet on January 1, 2022, exclusive of previously recognized lease balances. The implementation of Topic 842 did not have a material effect on the Company’s condensed consolidated statement of operations or condensed consolidated statement of cash flows for the year ended December 31, 2022. Financial Instruments In June 2016, the FASB issued ASU 2016-13, Financial Instruments – Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments. This guidance introduces a new model for recognizing credit losses on financial instruments based on an estimate of current expected credit losses. ASU 2016-13 also provides updated guidance regarding the impairment of available-for-sale debt securities and includes additional disclosure requirements. The Company adopted this guidance as of January 1, 2022. The Company regularly reviews its available-for-sale marketable securities and evaluates the current expected credit losses by considering factors such as any changes in credit ratings, historical experience, market data, issuer-specific factors, and current economic conditions. Based on this analysis, an allowance for credit losses is recorded as a reduction to the carrying value of the asset. To date, management has not recorded an allowance for credit losses. The Company reviews its receivable aging on an individual customer level, considering collectability of cash flows based on the risk of past events, current conditions, and forward-looking information. The Company establishes allowances for bad debts equal to the estimable portions of accounts receivable for which failure to collect is expected to occur. Allowances for doubtful accounts are recorded as reductions to the carrying values of the related receivables. To date, the Company has not recorded an allowance for doubtful accounts. Income taxes In December 2019, the FASB issued ASU No. 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes (“ASU 2019-12”), which aims to reduce complexity in accounting standards by improving certain areas of GAAP without compromising information provided to users of financial statements. ASU 2019-12 is effective for public entities for fiscal years beginning after December 15, 2020, and interim periods within those fiscal years. For all other entities, the standard is effective for fiscal years beginning after December 15, 2021, and interim periods within fiscal years beginning after December 15, 2022. The Company adopted this guidance beginning January 1, 2022 with no financial statement impact at adoption.

Significant Accounting Polici_3

Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2022
Significant Accounting Policies
Schedule of contract receivables	​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2022 December 31, 2021 Contract receivables not billed ​ $ 1,083 ​ $ 310 ​
Schedule of credit risk and major customers	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the Years Ended December 31, ​ 2022 2021 2020 Revenue Concentration ​ ​ ​ ​ Number of Customers ​ 4 4 3 ​ Related Total Revenue Percentage 82 % 87 % 81 % Contract Receivable Concentration ​ Number of Customers 2 2 1 ​ Related Contract Receivables Percentage 40 % 58 % 18 % ​
Summary of estimated useful life of property, plant and equipment	​ ​ ​ ​ ​ Depreciable Life - Years Commercial production equipment ​ 5 years Laboratory equipment ​ 5 years Furniture and Computer Equipment 3-7 years Leasehold improvements Lesser of asset life or lease term ​

Business Combination (Tables)

Business Combination (Tables)	12 Months Ended
	Dec. 31, 2022
Business Combination
Reconciliation of the business combination elements to the consolidated statements of cash flows and the consolidated statements of stockholders' equity	​ ​ ​ ​ ​ ​ Recapitalization Cash – DCRC trust and cash, net of redemptions ​ $ 347,914 Cash – PIPE Financing ​ 195,000 Cash – Sponsor Funds ​ 264 Non-cash net assets acquired from DCRC ​ (100,697) Less: transaction costs and advisory fees for Legacy Solid Power allocated to equity ​ (5,991) Less: transaction costs and advisory fees for DCRC ​ (41,897) Net Business Combination ​ $ 394,593 Add: non-cash net assets acquired from DCRC ​ 100,697 Add: accrued transaction costs and advisory fees ​ 80 Net cash contributions from Business Combination ​ $ 495,370 ​
Schedule of number of common shares outstanding following the consummation of the business combination	​ ​ ​ ​ ​ Number of Shares DCRC Class A common stock outstanding prior to Business Combination 43,710,000 DCRC Class B common stock outstanding prior to Business Combination 40,000 Less: redemption of DCRC Class A common stock (210,171) Shares of Common Stock issued in PIPE Financing 19,500,000 Shares of Common Stock issued to Legacy Solid Power stockholders 104,518,159 Total shares of Common Stock outstanding immediately after Business Combination 167,557,988

Property, Plant and Equipment (

Property, Plant and Equipment (Tables)	12 Months Ended
	Dec. 31, 2022
Property, Plant and Equipment
Summary of property and equipment	​ ​ ​ ​ ​ ​ ​ ​ ​ 2022 2021 Commercial production equipment ​ $ 21,595 ​ $ 9,139 Laboratory equipment ​ ​ 3,278 ​ ​ 1,316 Leasehold improvements ​ 27,996 ​ 4,674 Furniture and computer equipment ​ 1,482 ​ 737 Construction in progress ​ 40,036 ​ 12,684 Total cost ​ 94,387 ​ 28,550 Accumulated depreciation ​ (11,626) ​ (6,468) Net property and equipment ​ $ 82,761 ​ $ 22,082 ​
Schedule of depreciation and amortization expense	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ 2022 2021 2020 ​ ​ ​ ​ ​ ​ ​ Depreciation expense ​ $ 5,167 ​ $ 2,351 ​ $ 2,066 ​
Schedule of construction in progress	​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2022 December 31, 2021 Construction in progress ​ ​ Louisville, Colorado – 2 nd ​ $ 2,010 ​ $ 6,875 Louisville, Colorado – Other capital projects ​ 2,206 ​ — Thornton, Colorado – Increased scale electrolyte production ​ 35,820 ​ 943

Intangible Assets (Tables)

Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2022
Intangible Assets
Summary of intangible assets	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2022 2021 ​ ​ Gross Carrying ​ Accumulated ​ Gross Carrying ​ Accumulated ​ Amount Amortization Amount Amortization Intangible assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Licenses ​ $ 149 ​ $ (51) ​ $ 149 ​ $ (42) Patents pending ​ 984 ​ — ​ 503 ​ — Trademarks and trademarks pending ​ 26 ​ — ​ 9 ​ — Total amortized intangible assets ​ $ 1,159 ​ $ (51) ​ $ 661 ​ $ (42) ​

Long-term Debt (Tables)

Long-term Debt (Tables)	12 Months Ended
	Dec. 31, 2020
Long-term Debt
Summary of long-term debt	​ ​ ​ ​ ​ ​ ​ ​ ​ 2022 2021 Various equipment notes payable to banks in monthly installments ranging from $1 to $2 , including interest at 6.255 percent to 12.18 percent maturing from April 2022 through April 2023. The notes are collateralized by the financed equipment. ​ $ 7 ​ $ 130 Total ​ 7 ​ 130 Less current portion ​ 7 ​ 120 Long-term portion ​ $ — ​ $ 10 ​

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2022
Fair Value Measurements
Schedule of financial assets and liabilities measured and recorded at fair value on a recurring basis	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2022 ​ Level 1 Level 2 Level 3 Total Assets ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Commercial Paper ​ $ 165,179 ​ $ — ​ $ — ​ $ 165,179 Corporate Bonds ​ $ 227,957 ​ $ — ​ $ — ​ $ 227,957 Government Bonds ​ $ 42,865 ​ $ — ​ $ — ​ $ 42,865 U.S. Treasuries ​ 9,930 ​ ​ — ​ ​ — ​ 9,930 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Liabilities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Public Warrants ​ $ 4,900 ​ $ — ​ $ — ​ $ 4,900 Private Warrants ​ $ — ​ $ 4,217 ​ $ — ​ $ 4,217 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2021 ​ Level 1 Level 2 Level 3 Total Assets ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Commercial Paper ​ $ 33,275 ​ $ — ​ $ — ​ $ 33,275 Corporate Bonds ​ $ 39,593 ​ $ — ​ $ — ​ $ 39,593 Government Bonds ​ $ 3,017 ​ $ — ​ $ — ​ $ 3,017 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Liabilities ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Public Warrants ​ $ 26,483 ​ $ — ​ $ — ​ $ 26,483 Private Warrants ​ $ — ​ $ 23,537 ​ $ — ​ $ 23,537 ​
Schedule of Level 2 inputs used in the recurring valuation of the Private Placement Warrants	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2022 December 31, 2021 Exercise Price ​ $ 11.50 ​ $ 11.50 ​ Stock Price ​ $ 2.54 ​ $ 8.74 ​ Volatility ​ 71.3 % 48.9 % Term ​ 3.94 ​ 4.94 ​ Risk-free rate ​ 4.03 % 1.24 % ​
Schedule of reconciliation of warrants measured at fair value Level 1 directly observed	The following table provides a reconciliation of the Public Warrants measured at fair value using Level 1 directly observable inputs and Private Placement Warrants measured at fair value using Level 2 directly or indirectly observable inputs: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Public Warrants ​ Private Warrants ​ Level 1 Fair Value Level 2 Fair Value December 31, 2021 ​ $ 2.27 ​ $ 3.07 Change in fair value ​ $ (1.85) ​ $ (2.52) December 31, 2022 ​ $ 0.42 ​ $ 0.55 ​
Schedule of reconciliation of the warrants measured at fair value	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ Change in Fair ​ December 31, Warrant Class Level Shares 2021 Value 2022 Public Warrants 1 11,666,636 ​ $ 26,483 ​ $ (21,583) ​ $ 4,900 Private Warrants 2 7,666,667 ​ $ 23,537 ​ $ (19,320) ​ $ 4,217 Total 19,333,303 ​ $ 50,020 ​ $ (40,903) ​ $ 9,117

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2022
Stockholders' Equity
Schedule of stock options exercised	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ 2022 2021 2020 Stock options exercised ​ 8,428,524 ​ 1,160,930 ​ 1,097,370 ​

Stock Based Compensation (Table

Stock Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2022
Stock Based Compensation
Schedule of summary of stock option activity	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted-average ​ ​ ​ ​ ​ ​ ​ Remaining ​ ​ Number of ​ Weighted-average ​ Contractual Term Options Shares Exercise Price (in years) Outstanding at January 1, 2020 23,020,981 ​ $ 0.06 7.06 Granted 1,719,754 ​ $ 0.16 Exercised (1,097,370) ​ $ 0.02 Forfeited or expired (167,381) ​ $ 0.15 Outstanding at December 31, 2020 23,475,984 ​ $ 0.06 6.53 ​ ​ ​ ​ ​ ​ ​ ​ Outstanding at January 1, 2021 ​ 23,475,984 ​ $ 0.06 ​ 6.53 Granted 12,285,359 ​ $ 5.10 ​ Exercised ​ (1,160,930) ​ $ 0.09 ​ ​ Forfeited or expired (192,464) ​ $ 0.84 ​ Outstanding at December 31, 2021 ​ 34,407,949 ​ $ 1.86 ​ 6.98 ​ ​ ​ ​ ​ ​ ​ ​ Outstanding at January 1, 2022 ​ 34,407,949 ​ $ 1.86 ​ 6.98 Granted ​ 1,730,564 ​ $ 7.19 ​ ​ Exercised ​ (8,428,524) ​ $ 0.10 ​ ​ Forfeited or expired ​ (1,711,817) ​ $ 4.64 ​ ​ Outstanding at December 31, 2022 ​ 25,998,172 ​ $ 2.60 ​ 6.31 ​ ​ ​ ​ ​ ​ ​ ​ Exercisable at December 31, 2020 ​ 18,023,695 ​ $ 0.04 ​ 5.96 Exercisable at December 31, 2021 ​ 19,603,474 ​ $ 0.05 ​ 5.21 Exercisable at December 31, 2022 ​ 18,202,064 ​ $ 1.19 ​ 5.14 ​
Schedule of recognized & allocated compensation costs	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ 2022 2021 2020 Equity-based compensation costs related to RSUs ​ $ 1,567 ​ $ — ​ $ — Equity-based compensation costs related to stock options ​ 7,076 ​ 2,714 ​ 182 Equity-based compensation costs related to ESPP ​ 29 ​ — ​ — Total equity-based compensation costs ​ $ 8,672 ​ $ 2,714 ​ $ 182 Future compensation costs related to unvested options ​ $ 19,322 ​ $ 23,307 ​ $ 593 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ 2022 2021 2020 Direct Costs ​ $ 1,580 ​ $ 332 ​ $ 22 Research and Development ​ ​ 4,474 ​ ​ 1,698 ​ ​ 115 Sales and Marketing ​ ​ 493 ​ ​ 308 ​ ​ 23 General and Administrative ​ ​ 2,125 ​ ​ 376 ​ ​ 22 Total equity-based compensation cost ​ $ 8,672 ​ $ 2,714 ​ $ 182 ​
Schedule of weighted-average assumptions used in measuring fair value of options	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2022 2021 2020 Approximate risk-free rate ​ 2.84 % ​ 1.04 % ​ 1.29 % Volatility ​ 44.69 % ​ 41.45 % ​ 43.92 % Average expected life (years) ​ 6 years ​ 6 years ​ 6 years Dividend yield ​ 0 % ​ 0 % ​ 0 % Weighted-average grant date fair value ​ $ 7.26 ​ $ 5.10 ​ $ 0.84 ​ Estimated fair value of total options granted ​ $ 5,659 ​ $ 25,353 ​ $ 246 ​ ​
Schedule of non-vested Restricted stock units	​ ​ ​ ​ ​ ​ ​ ​ Number of Weighted-average ​ ​ Shares ​ Grant Date Fair Value Balance at January 1, 2022 — ​ Granted 1,292,429 ​ $ 7.11 Vested (29,108) ​ $ 7.26 Forfeited (205,341) ​ $ 7.33 Outstanding at December 31, 2022 1,057,980 ​ $ 7.06 ​
2021 Equity Incentive Plan
Stock Based Compensation
Schedule of summary of stock option activity	​ ​ ​ ​ ​ ​ ​ December 31, 2022 December 31, 2021 Option awards granted under 2021 Plan 1,730,564 — RSU awards granted under 2021 Plan ​ 1,292,429 ​ — ​

Earnings (Loss) Per Share (Tabl

Earnings (Loss) Per Share (Tables)	12 Months Ended
	Dec. 31, 2022
Earnings (Loss) Per Share
Schedule of reconciliation of basic weighted average common shares outstanding to diluted weighted average shares outstanding	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Years Ended December 31, ​ 2022 ​ 2021 ​ 2020 Net income (loss) attributable to common stockholders ​ $ (9,555) ​ $ 12,656 ​ $ (14,375) Weighted average shares outstanding – basic ​ ​ 174,374,386 ​ ​ 95,477,472 ​ ​ 69,228,444 Weighted average shares outstanding – diluted ​ 174,374,386 ​ 114,910,129 ​ ​ 69,228,444 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Basic earnings (loss) per share ​ $ (0.05) ​ $ 0.13 ​ $ (0.21) Diluted earnings (loss) per share ​ $ (0.05) ​ $ 0.11 ​ $ (0.21) ​
Schedule of potentially dilutive securities excluded from the diluted earnings (loss) per share calculation	​ ​ ​ ​ ​ ​ ​ ​ ​ 2022 2021 2020 Common Stock Warrants 19,333,303 19,333,303 ​ 1,023,745 2014 & 2021 Equity Incentive Plan - Stock Options 26,328,279 — ​ 23,476,182 2021 Equity Incentive Plan - Restricted Stock Units 710,385 — ​ — 2021 Employee Stock Purchase Plan ​ 26,589 ​ — ​ — Contingently Issuable Common Stock ​ 5,339 ​ — ​ — Total potentially dilutive securities ​ 46,403,895 ​ 19,333,303 ​ 24,499,927

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2022
Leases
Schedule of components of lease related expense	​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2022 December 31, 2021 Finance lease costs: ​ ​ Amortization of right-of-use assets ​ $ 92 ​ $ — Interest on lease liabilities ​ 28 ​ — Operating lease costs ​ 850 ​ — Total lease expense ​ $ 970 ​ $ — ​
Schedule of components of cash flow information related to leases	​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2022 December 31, 2021 Operating outgoing cash flows – finance lease ​ $ 24 ​ $ — Financing outgoing cash flows – finance lease ​ 142 ​ — Operating outgoing cash flows – operating lease ​ 568 ​ — Right-of-use assets obtained in exchange for new finance lease liabilities ​ 1,014 ​ — Right-of-use assets obtained in exchange for new operating lease liabilities ​ 8,947 ​ —
Schedule of remaining weighted-average lease term and weighted-average discount rate	​ ​ ​ ​ ​ ​ December 31, 2022 Finance lease ​ Weighted-average remaining lease term – finance lease (in years) 3.37 ​ Weighted-average discount rate – finance lease 5.9 % Operating lease ​ Weighted-average remaining lease term – operating lease (in years) 10.18 ​ Weighted-average discount rate – operating lease 6.9 % ​
Schedule of future minimum annual commitments under these operating leases	As of December 31, 2022, future minimum payments during the next five years and thereafter are as follows: ​ ​ ​ ​ ​ ​ ​ Fiscal year Finance Lease Operating Lease 2023 ​ $ 315 ​ $ 1,138 2024 ​ ​ 315 ​ ​ 1,173 2025 ​ ​ 192 ​ ​ 1,210 2026 ​ ​ 85 ​ ​ 1,248 2027 ​ ​ 37 ​ ​ 1,288 Thereafter ​ ​ 16 ​ ​ 6,571 Total ​ ​ 960 ​ ​ 12,628 Less present value discount ​ ​ 85 ​ ​ 3,457 Total lease liabilities ​ $ 875 ​ $ 9,171

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2022
Income Taxes
Schedule of income taxes	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the Years Ended December 31, ​ 2022 2021 2020 Deferred income tax (benefit) expense: ​ ​ ​ ​ ​ Federal ​ $ (195) ​ $ (22) ​ $ 96 State ​ ​ (32) ​ (3) ​ 22 Total income tax (benefit) expense ​ $ (227) ​ $ (25) ​ $ 118 ​
Schedule of reconciliation of the statutory federal income tax expense to income tax	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ 2022 2021 2020 Income tax expense at the federal statutory rate ​ 21.00 % 21.00 % 21.00 % State income benefits ​ 13.07 % (5.97) % 2.96 % Permanent Differences ​ (3.14) % 0.25 % 1.08 % Permanent Differences – Related to Convertible Debt ​ 0.00 % 0.31 % (5.04) % Permanent Differences – Fair Value Adjustments– Warrant Liability ​ 66.21 % (56.44) % 0.00 % Permanent Differences – Fair Value Adjustments– Marketable Securities ​ (5.13) % 0.00 % 0.00 % Prior year provision to return ​ 0.03 % (0.03) % (0.03) % Net change in valuation allowance ​ (104.28) % 40.73 % (20.81) % Research and Development ​ 13.65 % 0.00 % 0.00 % Other ​ 0.33 % 0.01 % 0.00 % Total income tax (benefit) ​ 1.75 % (0.14) % (0.84) % ​
Schedule of tax effects of temporary differences that give rise to significant portions of the deferred income tax assets and liabilities	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ 2022 2021 Deferred tax assets: ​ ​ ​ ​ Net operating loss ​ $ 17,962 ​ $ 15,591 R&D Credit ​ ​ 1,908 ​ ​ — Stock compensation ​ ​ 1,991 ​ ​ 417 Section 174 Capitalization ​ ​ 5,731 ​ ​ — ROU Lease Liability ​ ​ 2,459 ​ ​ — Other ​ 748 ​ 49 Total income tax expense (benefit) ​ 30,799 ​ 16,057 Valuation allowance ​ (28,030) ​ (14,536) Net deferred tax assets: ​ 2,769 ​ 1,521 Deferred tax liabilities: ​ ​ Intangibles (non-goodwill) ​ $ (1) ​ $ — Property and equipment ​ (652) ​ (1,747) ROU Asset ​ ​ (2,116) ​ ​ — Total deferred tax liabilities ​ (2,769) ​ (1,747) Total net deferred tax liability ​ $ — ​ $ (226) ​
Schedule of unrecognized tax benefits	​ ​ ​ ​ ​ ​ December 31, 2022 Balance, beginning of year ​ $ — Gross increases related to prior period tax position ​ — Gross increases related to current period tax position ​ 636 Gross decreases related to prior period tax position ​ — Balance, end of year ​ $ 636 ​

Significant Accounting Polici_4

Significant Accounting Policies (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2022 USD ($) segment	Dec. 31, 2021 USD ($)
Segment Reporting
Number of operating segment	1
Number of reportable segment	1
Contract Receivables
Contract receivables not billed | $	$ 1,083	$ 310

Significant Accounting Polici_5

Significant Accounting Policies - Credit Risk and Major Customers (Details) - customer	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Revenue | Customer concentration | Three customers
Concentration risk
Number of customers			3
Concentration risk percentage			81%
Revenue | Customer concentration | Four customers
Concentration risk
Number of customers	4	4
Concentration risk percentage	82%	87%
Contract receivables | Customer concentration | One customer
Concentration risk
Number of customers			1
Contract receivables | Customer concentration | Two customers
Concentration risk
Number of customers	2	2
Contract receivables | Credit concentration | One customer
Concentration risk
Concentration risk percentage			18%
Contract receivables | Credit concentration | Two customers
Concentration risk
Concentration risk percentage	40%	58%

Significant Accounting Polici_6

Significant Accounting Policies - Property and Equipment (Details)	12 Months Ended
	Dec. 31, 2022
Commercial production equipment
Property and Equipment
Estimated useful lives	5 years
Laboratory equipment
Property and Equipment
Estimated useful lives	5 years
Furniture And Computer Equipment | Minimum
Property and Equipment
Estimated useful lives	3 years
Furniture And Computer Equipment | Maximum
Property and Equipment
Estimated useful lives	7 years

Significant Accounting Polici_7

Significant Accounting Policies - Intangible Assets (Details)	12 Months Ended
	Dec. 31, 2022
Minimum
Intangible Assets
Estimated useful life of intangible assets	3 years
Maximum
Intangible Assets
Estimated useful life of intangible assets	20 years

Significant Accounting Polici_8

Significant Accounting Policies - Additional information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 30, 2022	Jan. 01, 2022
Significant Accounting Policies
Expected dividend yield	0%	0%	0%
Collaborative and Support Revenue
Deferred revenue	$ 4,050	$ 500
Research and Development
Research and development expense	38,592	17,102	$ 9,594
Income Taxes
Uncertain tax position	636	0		$ 0
Interest or penalties	0	$ 0	$ 0
Right-of-use Asset	7,725				$ 7,853
Lease liability	$ 8,622				$ 8,246

Significant Accounting Polici_9

Significant Accounting Policies - Mezzanine Equity (Details) - Legacy Solid Power	12 Months Ended
	Dec. 31, 2022 shares
Mezzanine Equity
Conversion ratio	1
Series A1 Preferred Stock
Mezzanine Equity
Number of shares converted into common stock	14,069,187
Series B Preferred Stock
Mezzanine Equity
Number of shares converted into common stock	8,777,812

Business Combination - Reconcil

Business Combination - Reconciliation (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2021 USD ($)
Business Combination
Cash - DCRC trust and cash, net of redemptions	$ 347,914
Cash - PIPE Financing	195,000
Cash - Sponsor Funds	264
Non-cash net assets acquired from DCRC	(100,697)
Less: transaction costs and advisory fees for Legacy Solid Power allocated to equity	(5,991)
Less: transaction costs and advisory fees for DCRC	(41,897)
Net Business Combination	394,593
Add: non-cash net assets acquired from DCRC	100,697
Add: accrued transaction costs and advisory fees	80
Net cash contributions from Business Combination	$ 495,370

Business Combination - Number o

Business Combination - Number of common stock shares outstanding (Details) - shares	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Business Combination
Less: redemption of DCRC Class A common stock		(210,171)
Shares of Common Stock issued in PIPE Financing		19,500,000
Total shares of Common Stock outstanding immediately after Business Combination	176,007,184	167,557,988
Legacy Solid Power
Business Combination
Number of common stock shares issued	104,518,159	104,518,159
Class A Common Stock
Business Combination
DCRC common stock outstanding prior to Business Combination		43,710,000
Class B Common Stock
Business Combination
DCRC common stock outstanding prior to Business Combination		40,000

Business Combination - Addition

Business Combination - Additional information (Details) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2022 USD ($) $ / shares shares	Dec. 31, 2021 USD ($) $ / shares shares
Business Combination
Goodwill | $	$ 0
Common stock, par value | $ / shares	$ 0.0001	$ 0.0001
Exchange ratio	3.182
Number of shares issued		19,500,000
Aggregate purchase price | $		$ 195,000
Private Warrants
Business Combination
Number of warrants outstanding	7,666,667	7,666,667
DCRC
Business Combination
Fair value of acquired common stock warrants | $	$ 101,253
DCRC | Private Warrants
Business Combination
Number of warrants outstanding	7,666,667
DCRC | Sponsor
Business Combination
Number of warrants to purchase common stock	1,000,000
Warrants price per share | $ / shares	$ 1.50
DCRC | Sponsor | Working capital loans
Business Combination
Outstanding balance | $	$ 1,500
Subscription agreement ("PIPE Shares")
Business Combination
Number of shares issued	19,500,000
Price per share | $ / shares	$ 10
Aggregate purchase price | $	$ 195,000
Class B Common Stock
Business Combination
Conversion of stock	1
Class B Common Stock | DCRC
Business Combination
Number of shares issued	40,000
DCRC
Business Combination
Common stock, par value | $ / shares	$ 0.0001
Legacy Solid Power
Business Combination
Common stock, par value | $ / shares	$ 0.0001
Number of common stock shares issued	104,518,159	104,518,159
Options exercisable	34,407,949

Property and Equipment (Details

Property and Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Property and Equipment
Gross property and equipment	$ 94,387	$ 28,550
Accumulated depreciation	(11,626)	(6,468)
Net property and equipment	82,761	22,082
Depreciation and amortization expense	5,176	2,360	$ 2,067
Property, Plant and Equipment
Property and Equipment
Depreciation and amortization expense	5,167	2,351	$ 2,066
Commercial production equipment
Property and Equipment
Gross property and equipment	21,595	9,139
Laboratory equipment
Property and Equipment
Gross property and equipment	3,278	1,316
Leasehold improvements
Property and Equipment
Gross property and equipment	27,996	4,674
Furniture and computer equipment
Property and Equipment
Gross property and equipment	1,482	737
Construction in progress
Property and Equipment
Gross property and equipment	$ 40,036	$ 12,684

Property, Plant and Equipment -

Property, Plant and Equipment - Construction in progress (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Louisville, Colorado - 2nd cell pilot line
Property, Plant and Equipment
Construction in progress	$ 2,010	$ 6,875
Louisville, Colorado - Other capital projects
Property, Plant and Equipment
Construction in progress	2,206
Thornton, Colorado - Increased scale electrolyte production
Property, Plant and Equipment
Construction in progress	$ 35,820	$ 943

Intangible Assets (Details)

Intangible Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Intangible assets:
Gross Carrying Amount	$ 1,159	$ 661
Accumulated Amortization	(51)	(42)
Amortization expense for intangible assets	$ 9	9	$ 9
Minimum
Intangible assets:
Useful lives of intangible assets	3 years
Maximum
Intangible assets:
Useful lives of intangible assets	20 years
Licenses
Intangible assets:
Gross Carrying Amount	$ 149	149
Accumulated Amortization	(51)	(42)
Patents
Intangible assets:
Gross Carrying Amount	984	503
Trademarks
Intangible assets:
Gross Carrying Amount	$ 26	$ 9

Long-term Debt (Details)

Long-term Debt (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Long-term Debt
Total	$ 7	$ 130
Less current portion	7	120
Long-term portion		10
Interest expense on long-term debt	6	131	$ 196
Various equipment notes payable to banks
Long-term Debt
Total	7	$ 130
Various equipment notes payable to banks | Minimum
Long-term Debt
Monthly installments amount	$ 1
Debt interest rate	6.255%
Various equipment notes payable to banks | Maximum
Long-term Debt
Monthly installments amount	$ 2
Debt interest rate	12.18%

Convertible Notes Payable (Deta

Convertible Notes Payable (Details)			12 Months Ended
	May 05, 2021 USD ($) shares	Dec. 04, 2019 USD ($) shares	Dec. 31, 2022 USD ($) item	Dec. 31, 2020 USD ($)	Mar. 01, 2021 USD ($)	Feb. 04, 2021 USD ($)	Dec. 18, 2020 USD ($)	Dec. 10, 2020 USD ($)	Dec. 31, 2019
Convertible Notes Payable
Number of embedded derivative | item			1
Loss from change in fair value of debt				$ 437,000
2020 Convertible Promissory Notes
Convertible Notes Payable
Principal amount					$ 4,875,000	$ 4,875,000	$ 5,125,000	$ 5,125,000
Interest rate			8%
Interest expense			$ 210,000
2020 Convertible Promissory Notes | Series B Preferred Stock
Convertible Notes Payable
Number of shares issued in conversion | shares	1,007,965
Convertible note payable	$ 10,228,000
Fair value of the embedded derivative	$ 5,497,000
2019 Convertible Promissory Notes
Convertible Notes Payable
Principal amount		$ 3,000
Interest rate		5%
Convertible note payable				$ 150,000
Interest expense			$ 53,000
2019 Convertible Promissory Notes | Series B Preferred Stock
Convertible Notes Payable
Interest rate									30%
Number of shares issued in conversion | shares		254,899

Fair Value Measurements - Asset

Fair Value Measurements - Assets and liabilities measured and recorded at fair value on recurring basis (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Liabilities
Long term marketable securities	$ 0
Purchase of marketable securities	561,565	$ 75,885
Recurring | Public Warrants
Liabilities
Warrant liabilities	4,900	26,483
Recurring | Private Warrants
Liabilities
Warrant liabilities	4,217	23,537
Recurring | Level 1 | Public Warrants
Liabilities
Warrant liabilities	4,900	26,483
Recurring | Level 2 | Private Warrants
Liabilities
Warrant liabilities	4,217	23,537
Recurring | Level 3
Liabilities
Transfers in or out of Level 3	0	0
Recurring | Commercial Paper
Assets
Assets	165,179	33,275
Recurring | Commercial Paper | Level 1
Assets
Assets	165,179	33,275
Recurring | Corporate Bonds
Assets
Assets	227,957	39,593
Recurring | Corporate Bonds | Level 1
Assets
Assets	227,957	39,593
Recurring | Municipal Bonds
Assets
Assets	42,865	3,017
Recurring | Municipal Bonds | Level 1
Assets
Assets	42,865	$ 3,017
Recurring | U.S. Treasuries
Assets
Assets	9,930
Recurring | U.S. Treasuries | Level 1
Assets
Assets	$ 9,930

Fair Value Measurements - Fair

Fair Value Measurements - Fair Value Methodology (Details) - 2019 Convertible Promissory Notes $ in Thousands	Dec. 31, 2020 USD ($)
Fair Value Measurements
Principal Amount	$ 3,000
Fair Value	$ 3,612

Fair Value Measurements - Measu

Fair Value Measurements - Measurement inputs (Details) - Recurring - Level 2 - Private Warrants	Dec. 31, 2022 Y $ / shares	Dec. 31, 2021 $ / shares Y
Exercise Price
Fair Value Measurements
Measurement input, warrants	11.50	11.50
Stock Price
Fair Value Measurements
Measurement input, warrants	2.54	8.74
Volatility
Fair Value Measurements
Measurement input, warrants	0.713	0.489
Term
Fair Value Measurements
Measurement input, warrants | Y	3.94	4.94
Risk-free rate
Fair Value Measurements
Measurement input, warrants	0.0403	0.0124

Fair Value Measurements - Recon

Fair Value Measurements - Reconciliation (Details) - Private Warrants - Recurring	12 Months Ended
	Dec. 31, 2022 $ / shares
Level 1
Reconciliation
Beginning balance, per share	$ 2.27
Change in fair value	(1.85)
Ending balance, per share	0.42
Level 2
Reconciliation
Beginning balance, per share	3.07
Change in fair value	(2.52)
Ending balance, per share	$ 0.55

Fair Value Measurements - Class

Fair Value Measurements - Class of warrant (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Defined Benefit Plan Disclosure [Line Items]
Balance at the end	$ 9,117
Recurring
Defined Benefit Plan Disclosure [Line Items]
Number of warrants outstanding	19,333,303
Balance at the beginning	$ 50,020
Change in fair value	(40,903)
Balance at the end	$ 9,117
Public Warrants
Defined Benefit Plan Disclosure [Line Items]
Number of warrants outstanding	11,666,636	11,666,636
Private Warrants
Defined Benefit Plan Disclosure [Line Items]
Number of warrants outstanding	7,666,667	7,666,667
Level 1 | Public Warrants | Recurring
Defined Benefit Plan Disclosure [Line Items]
Number of warrants outstanding	11,666,636
Balance at the beginning	$ 26,483
Change in fair value	(21,583)
Balance at the end	$ 4,900
Level 2 | Private Warrants | Recurring
Defined Benefit Plan Disclosure [Line Items]
Number of warrants outstanding	7,666,667
Balance at the beginning	$ 23,537
Change in fair value	(19,320)
Balance at the end	$ 4,217

Common Stock Warrant Liabilit_2

Common Stock Warrant Liabilities (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2022	Dec. 31, 2021
Common Stock Warrant Liabilities
Trading days considered in the calculation of fair market value		10 days
Fair value, measurement with unobservable inputs reconciliation, recurring basis, liability value		$ 9,117
Change in fair value of warrant liabilities	$ 51,233	$ 40,903	$ 51,233
Fair Value, Liability, Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]		Change in fair value of warrant liabilities	Change in fair value of warrant liabilities
Redemption of Public Warrants when the price per share of Common Stock equals or exceeds $18.00
Common Stock Warrant Liabilities
Stock price trigger for redemption of public warrants (in dollars per share)		$ 18
Sale Price Of Common Stock Equal Or Exceeds To 18.00 Per Share
Common Stock Warrant Liabilities
Class of warrant or right minimum threshold written notice period for redemption of warrants		30 days
Sale Price Of Common Stock Equal Or Exceeds To 10.00 Per Share
Common Stock Warrant Liabilities
Class of warrant or right minimum threshold written notice period for redemption of warrants		30 days
Warrants
Common Stock Warrant Liabilities
Class of warrant or right, number of securities called by each warrant or right	1	1	1
Exercise price of warrants	$ 11.50	$ 11.50	$ 11.50
Fair value, measurement with unobservable inputs reconciliation, recurring basis, liability value	$ 50,020	$ 101,253	$ 50,020
Warrants | Sale Price Of Common Stock Equal Or Exceeds To 18.00 Per Share
Common Stock Warrant Liabilities
Redeemable price per warrant		$ 0.01
Trigger price		$ 18
Threshold trading days for which the entity sends notice of redemption		20 days
Threshold consecutive trading days for which the entity sends notice of redemption		30 days
Warrants | Sale Price Of Common Stock Equal Or Exceeds To 10.00 Per Share
Common Stock Warrant Liabilities
Redeemable price per warrant		$ 0.10
Trigger price		$ 10
Public Warrants
Common Stock Warrant Liabilities
Number of warrants outstanding	11,666,636	11,666,636	11,666,636
Public Warrants | Redemption of Public Warrants when the price per share of Common Stock equals or exceeds $10.00
Common Stock Warrant Liabilities
Stock price trigger for redemption of public warrants (in dollars per share)		$ 10
Private Warrants
Common Stock Warrant Liabilities
Number of warrants outstanding	7,666,667	7,666,667	7,666,667

Mezzanine Equity (Details)

Mezzanine Equity (Details) - USD ($) $ in Thousands		1 Months Ended
	Dec. 07, 2021	May 31, 2021
Series A1 Preferred Stock
Mezzanine Equity
Shares outstanding	14,069,187
Preferred Stock converted into shares	14,069,187
Series B Preferred Stock
Mezzanine Equity
Shares outstanding	8,777,812
Minimum net cash proceeds for conversion		$ 135,579
Preferred Stock converted into shares	8,777,812

Stockholders' Equity (Details)

Stockholders' Equity (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2015	May 31, 2021
Stockholders' Equity
Expenses related to issuance of warrants			$ 16
Cash received from options exercised	$ 818	$ 106	23
2014 Equity Incentive Plan
Stockholders' Equity
Cash received from options exercised	$ 818	$ 106	$ 24
Common Stock
Stockholders' Equity
Stock options exercised (in shares)	8,428,524	1,160,930	1,097,370
Common Stock | Restricted stock units (RSUs)
Stockholders' Equity
Stock options exercised (in shares)	29,108	0	0
Warrants
Stockholders' Equity
Warrants to purchase shares of common stock			45,730	276,000	1,755,557
Exercise price of warrants			$ 0.53	$ 0.00001088	$ 0.01
Expenses related to issuance of warrants			$ 16	$ 18

Stock Based Compensation - 2014

Stock Based Compensation - 2014 Equity Incentive Plan and 2021 Equity Incentive Plan (Details)		12 Months Ended
	Apr. 01, 2022	Dec. 31, 2022 installment shares	Dec. 31, 2021 shares	Dec. 08, 2021 shares
Restricted stock units (RSUs)
Stock Based Compensation
Number of common shares for each RSU upon vesting		1
Awards granted under 2021 Plan		1,292,429
Restricted stock units (RSUs) | Vesting after year one
Stock Based Compensation
Number of successive equal number of installments of remaining vesting shares, vested | installment		12
Restricted stock units (RSUs) | Share Based Payment Arrangement Employee
Stock Based Compensation
Vesting percentage	25%
2014 Plan
Stock Based Compensation
Options terms		10 years
Vesting percentage		75%
Options outstanding		24,766,176	34,407,949
2014 Plan | Vesting after year one
Stock Based Compensation
Vesting percentage		25%
2014 Plan | Vesting after year two
Stock Based Compensation
Number of successive equal number of installments of remaining vesting shares, vested | installment		36
2021 Equity Incentive Plan
Stock Based Compensation
Number of shares permitted to grant				18,900,000
Number of additional shares		18,900,000
Percentage on shares outstanding added to shares available for issuance		5%
Options outstanding		24,466,527
Awards granted under 2021 Plan		1,730,564
2021 Equity Incentive Plan | Employee stock option
Stock Based Compensation
Options terms		10 years
2021 Equity Incentive Plan | Employee stock option | Vesting after year one
Stock Based Compensation
Vesting percentage		25%

Stock Based Compensation - Shar

Stock Based Compensation - Share based compensation plan (Details)	12 Months Ended
	Dec. 31, 2022 shares
2021 Equity Incentive Plan
Stock Based Compensation
Awards granted under 2021 Plan	1,730,564

Stock Based Compensation - Comp

Stock Based Compensation - Compensation costs (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Stock Based Compensation
Compensation costs	$ 8,672	$ 2,714	$ 182
Future compensation costs related to unvested options	19,322	23,307	593
Restricted stock units (RSUs)
Stock Based Compensation
Compensation costs	1,567
Employee stock option
Stock Based Compensation
Compensation costs	7,076	$ 2,714	$ 182
ESPP
Stock Based Compensation
Compensation costs	$ 29

Stock Based Compensation - Allo

Stock Based Compensation - Allocated compensation costs (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Stock Based Compensation
Equity-based compensation cost	$ 8,672	$ 2,714	$ 182
Direct Costs
Stock Based Compensation
Equity-based compensation cost	1,580	332	22
Research and Development
Stock Based Compensation
Equity-based compensation cost	4,474	1,698	115
Sales and Marketing
Stock Based Compensation
Equity-based compensation cost	493	308	23
General and Administrative
Stock Based Compensation
Equity-based compensation cost	$ 2,125	$ 376	$ 22

Stock Based Compensation - Weig

Stock Based Compensation - Weighted-average assumptions (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Stock Based Compensation
Approximate risk-free rate	2.84%	1.04%	1.29%
Volatility	44.69%	41.45%	43.92%
Average expected life (years)	6 years	6 years	6 years
Dividend yield	0%	0%	0%
Weighted-average grant date fair value	$ 7.26	$ 5.10	$ 0.84
Estimated fair value of total options granted (in thousands)	$ 5,659	$ 25,353	$ 246

Stock Based Compensation - Summ

Stock Based Compensation - Summary of option activity (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Weighted-average Remaining Contractual Term (in years)
Cash received from options exercised	$ 818	$ 106	$ 23
Aggregate intrinsic value of exercisable option	35,058
Aggregate intrinsic value of exercised options	$ 63,287
2014 and 2021 Equity Incentive Plan
Number of Shares
Outstanding at beginning of period	34,407,949	23,475,984	23,020,981
Granted	1,730,564	12,285,359	1,719,754
Exercised	(8,428,524)	(1,160,930)	(1,097,370)
Forfeited or expired	(1,711,817)	(192,464)	(167,381)
Outstanding at end of period	25,998,172	34,407,949	23,475,984	23,020,981
Exercisable	18,202,064	19,603,474	18,023,695
Weighted-average Exercise Price
Outstanding at beginning of period	$ 1.86	$ 0.06	$ 0.06
Granted	7.19	5.10	0.16
Exercised	0.10	0.09	0.02
Forfeited or expired	4.64	0.84	0.15
Outstanding at end of period	2.60	1.86	0.06	$ 0.06
Exercisable	$ 1.19	$ 0.05	$ 0.04
Weighted-average Remaining Contractual Term (in years)
Weighted average remaining contractual term	6 years 3 months 21 days	6 years 11 months 23 days	6 years 6 months 10 days	7 years 21 days
Exercisable	5 years 1 month 20 days	5 years 2 months 15 days	5 years 11 months 15 days
2014 Plan
Number of Shares
Outstanding at beginning of period	34,407,949
Outstanding at end of period	24,766,176	34,407,949
Weighted-average Remaining Contractual Term (in years)
Cash received from options exercised	$ 818	$ 106	$ 23

Stock Based Compensation - Rest

Stock Based Compensation - Restricted Stock Units (Details) - Restricted stock units (RSUs) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2022 USD ($) $ / shares shares
Number of Shares
Outstanding at beginning of period	0
Granted	1,292,429
Vested	(29,108)
Forfeited	(205,341)
Outstanding at end of period	1,057,980
Weighted-average Grant Date Fair Value
Granted | $ / shares	$ 7.11
Vested | $ / shares	7.26
Forfeited | $ / shares	7.33
Outstanding at end of period | $ / shares	$ 7.06
Unrecognized compensation costs related to restricted stock units | $	$ 6,144
Weighted average period	2 years 11 months 19 days
Intrinsic value | $	$ 0

Stock Based Compensation - 2021

Stock Based Compensation - 2021 Employee Stock Purchase Plan (Details) - USD ($) $ in Thousands		12 Months Ended
	Jan. 01, 2022	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 08, 2021
Stock Based Compensation
Compensation costs		$ 8,672	$ 2,714	$ 182
Unrecognized compensation expense		$ 19,322	$ 23,307	$ 593
2021 ESPP
Stock Based Compensation
Common Stock available for issuance		5,463,579	3,778,000		3,778,000
Number of shares permitted to deliver		5,463,579
Percentage limit on commons stock shares outstanding	1%
Compensation costs		$ 29
Awards granted under 2021 Plan		0
Number of additional shares	3,778,000
Unrecognized compensation expense		$ 58
Threshold percentage of the combined voting power		5%
Threshold percentage on the fair market value		85%
Maximum percentage of the qualified compensation		15%
Annual limit		$ 25,000

Earnings (Loss) Per Share (Deta

Earnings (Loss) Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Earnings (Loss) Per Share
Net income (loss) attributable to common stockholders	$ (9,555)	$ 12,656	$ (14,375)
Weighted average shares outstanding - basic	174,374,386	95,477,472	69,228,444
Weighted average shares outstanding - diluted	174,374,386	114,910,129	69,228,444
Basic earnings (loss) per share	$ (0.05)	$ 0.13	$ (0.21)
Diluted earnings (loss) per share	$ (0.05)	$ 0.11	$ (0.21)

Earnings (Loss) Per Share - Pot

Earnings (Loss) Per Share - Potentially dilutive securities (Details) - shares	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Earnings (Loss) Per Share
Total potentially dilutive securities	46,403,895	19,333,303	24,499,927
Common Stock Warrants
Earnings (Loss) Per Share
Total potentially dilutive securities	19,333,303	19,333,303	1,023,745
2014 & 2021 Equity Incentive Plan
Earnings (Loss) Per Share
Total potentially dilutive securities	26,328,279		23,476,182
2021 Equity Incentive Plan
Earnings (Loss) Per Share
Total potentially dilutive securities	710,385
2021 Employee Stock Purchase Plan
Earnings (Loss) Per Share
Total potentially dilutive securities	26,589
Contingently Issuable Common Stock
Earnings (Loss) Per Share
Total potentially dilutive securities	5,339

Leases - Components of lease (D

Leases - Components of lease (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Sep. 01, 2021
Leases
Operating lease renewal term (in years)		5 years
Finance lease costs:
Amortization of right-of-use assets	$ 92
Interest on lease liabilities	28
Operating lease costs	850
Total lease expense	$ 970

Leases - Components of suppleme

Leases - Components of supplemental cash flow information (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2022 USD ($)
Leases
Operating outgoing cash flows - finance lease	$ 24
Financing outgoing cash flows - finance lease	142
Operating outgoing cash flows - operating lease	568
Right-of-use assets obtained in exchange for new finance lease liabilities	1,014
Right-of-use assets obtained in exchange for new operating lease liabilities	$ 8,947

Leases - Lease term and discoun

Leases - Lease term and discount rate (Details)	Dec. 31, 2022
Leases
Weighted-average remaining lease term - finance lease (in years)	3 years 4 months 13 days
Weighted-average discount rate - finance lease	5.90%
Weighted-average remaining lease term - operating lease (in years)	10 years 2 months 4 days
Weighted-average discount rate - operating lease	6.90%

Leases - Schedule of future min

Leases - Schedule of future minimum payments (Details) $ in Thousands	Dec. 31, 2022 USD ($)
Finance Lease
2023	$ 315
2024	315
2025	192
2026	85
2027	37
Thereafter	16
Total	960
Less present value discount	85
Total lease liabilities	875
Operating Lease
2023	1,138
2024	1,173
2025	1,210
2026	1,248
2027	1,288
Thereafter	6,571
Total	12,628
Less present value discount	3,457
Total lease liabilities	$ 9,171

Related Party Transactions (Det

Related Party Transactions (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2020	Dec. 31, 2021
Related Party Transactions
Deferred revenue	$ 4,050		$ 500
Roccor
Related Party Transactions
Total value of the subcontract		$ 331
Revenue from Related Parties		$ 163
BMW
Related Party Transactions
Revenue subject to achieving certain milestones	20,000
Revenue from Related Parties	2,000
Deferred revenue	4,000
Proceeds from related party for exchange for initial prototype cells	$ 375

Retirement plan (Details)

Retirement plan (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Retirement Plans
Contributions to the plan	$ 802	$ 352	$ 226

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Deferred income tax (benefit) expense:
Federal	$ (195)	$ (22)	$ 96
State	(32)	(3)	22
Total income tax (benefit) expense	$ (227)	$ (25)	$ 118

Income Taxes - Reconciliation o

Income Taxes - Reconciliation of the statutory federal income tax expense (Details)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Effective Tax Rate
Income tax expense at the federal statutory rate	21%	21%	21%
State income taxes - net of federal income tax benefits	13.07%	(5.97%)	2.96%
Permanent Differences	(3.14%)	0.25%	1.08%
Permanent Differences - Related to Convertible Debt	0%	0.31%	(5.04%)
Permanent Differences - Fair Value Adjustments- Warrant Liability	66.21%	(56.44%)	0%
Permanent Differences - Fair Value Adjustments- Marketable Securities	(5.13%)	0%	0%
Prior year provision to return	0.03%	(0.03%)	(0.03%)
Net change in valuation allowance	(104.28%)	40.73%	(20.81%)
Research and Development	13.65%	0%	0%
Other	0.33%	0.01%	0%
Total income tax (benefit)	1.75%	(0.14%)	(0.84%)

Income Taxes - Deferred income

Income Taxes - Deferred income tax assets and liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Deferred tax assets:
Net operating loss	$ 17,962	$ 15,591
R&D Credit	1,908
Stock compensation	1,991	417
Section 174 Capitalization	5,731
ROU Lease Liability	2,459
Other	748	49
Total income tax expense (benefit)	30,799	16,057
Valuation allowance	(28,030)	(14,536)
Net deferred tax assets:	2,769	1,521
Deferred tax liabilities:
Intangibles (non-goodwill)	(1)
Property and equipment	(652)	(1,747)
ROU Asset	(2,116)
Total deferred tax liabilities	$ (2,769)	(1,747)
Total net deferred tax liability		$ (226)

Income Taxes - Additional infor

Income Taxes - Additional information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 30, 2022	Dec. 31, 2021	Dec. 31, 2020
Income Taxes
Increase in valuation allowance	$ 13,494,000
Federal net operating loss carryovers	$ 73,367,000		$ 63,391,000	$ 29,836,000
Percentage of offset on taxable income for Federal net operating loss carryovers	80%
Uncertain tax benefits	$ 636,000	$ 0	$ 0
Accrued interest or penalties related to uncertain tax positions	$ 0

Income Taxes - Unrecognized tax

Income Taxes - Unrecognized tax benefits (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2022 USD ($)
Unrecognized tax benefits
Balance, beginning of year	$ 0
Gross increases related to prior period tax position	0
Gross increases related to current period tax position	636
Gross decreases related to prior period tax position	0
Balance, end of year	$ 636

Contingencies (Details)

Contingencies (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Contingencies
Deferred revenue	$ 4,050	$ 500
Minimum period for which Company has sufficient capital to execute its strategic plan and fund operations	12 months