X0609 4 2026-05-20 0 0001844862 Solid Power, Inc. SLDP 0001903970 Roe Lesa B false C/O SOLID POWER, INC. 486 S PIERCE AVE, SUITE E LOUISVILLE CO 80027 1 0 0 0 1 Common Stock 2026-05-20 4 A 0 44133 0 A 283182 D Common Stock 2026-05-20 4 S 0 39207 2.66 D 243975 D Represents restricted stock units, which upon vesting of the unit, represent the right to receive one share of the issuer's common stock. The restricted stock units vest upon the earlier of: (i) the first anniversary of the grant date or (ii) the day before the issuer's next annual meeting of stockholders following the grant date, in each case, subject to the reporting person continuing to be a service provider (as defined in the Solid Power, Inc. 2021 Equity Incentive Plan) through such vesting date. This sale was made pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on December 23, 2025 (the "10b5-1 Plan"). The 10b5-1 Plan was established to cover the reporting person's tax liability arising from vesting of restricted stock units. /s/ Kristen Gould, attorney-in-fact on behalf of Lesa B. Roe 2026-05-21