DCRC Decarbonization Plus Acquisition Corporation III

CUSIP No. 83422N 105

Explanatory Note

This Amendment No. 4 to Schedule 13D (this “Amendment No. 4”) is being filed to amend the statement on Schedule 13D filed by Douglas Campbell (the “Reporting Person”) on December 15, 2021 (the “Original Statement”), as amended by Amendment No. 1 to the Original Statement filed on January 13, 2022, as amended by Amendment No. 2 to the Original Statement filed on June 28, 2022, as amended by Amendment No. 3 to the Original Statement filed on August 29, 2022 (as so amended, the “Schedule 13D”), and relates to shares of common stock, par value $0.0001 per share (the “Common Stock”), of Solid Power, Inc. (f/k/a Decarbonization Plus Acquisition Corporation III), a Delaware corporation (the “Issuer”).

The Schedule 13D is hereby amended and supplemented as detailed below, and, except as amended and supplemented hereby, the Schedule 13D remains in full force and effect. All capitalized terms not otherwise defined herein shall have the meaning ascribed to such terms in the Schedule 13D.

Item 5. Interest in Securities of the Issuer.

Item 5 of the Schedule 13D is hereby amended and restated in its entirety to read as follows:

(a) As of the date of this Amendment No. 4, the Reporting Person beneficially owns an aggregate of 9,650,202 shares of Common Stock, or approximately 5.2% of the Issuer’s Common Stock. The beneficial ownership percentages used in this Schedule 13D are calculated based on a total of 174,545,062 shares of Common Stock outstanding as of August 5, 2022, which equals the number of shares of Common Stock as set forth in the Issuer’s Form 10-Q filed with the Securities and Exchange Commission on August 10, 2022, plus 139,211 shares of Common Stock deemed to be beneficially owned by Mr. Campbell that are issuable upon exercise of options that have vested or are scheduled to vest within 60 days of the date of this Amendment No. 4 and held by Mr. Campbell.

(b) The Reporting Person has sole voting and dispositive power with respect to 9,510,991 shares of Common Stock and 139,211 shares of Common Stock issuable upon exercise of options that have vested or are scheduled to vest within 60 days of the date of this Amendment No. 4.

(c) The following table details the transactions by the Reporting Person during the past 60 days on or prior to the Reporting Date and which were not previously disclosed in a prior Amendment. The Reporting Person sold shares during an open trading window in order to obtain liquidity necessary to satisfy expected tax obligations arising from the exercise by the Reporting Person of stock options in January 2022 that were set to expire in February 2022.

⁽¹⁾        This transaction was executed in multiple trades at prices ranging from $6.635 to $6.955. The price reported above reflects the weighted average price.

⁽²⁾        This transaction was executed in multiple trades at prices ranging from $6.55 to $6.865. The price reported above reflects the weighted average price.

⁽³⁾        This transaction was executed in multiple trades at prices ranging from $6.405 to $6.69. The price reported above reflects the weighted average price.

(d) Except as disclosed in Item 2, no person is known to the Reporting Person to have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, any securities covered by this Schedule 13D.

(e) Not Applicable.

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Date: September 1, 2022