On July 10, 2025, the Company entered into a Sale and Leaseback Agreement with UOP, an affiliate of Honeywell, a related party, pursuant to which UOP agreed to purchase the stack assembly line used to build power module stacks for the Company’s iron flow products, including Energy Base, for a purchase price of $10.5 million (comprised of $4.0 million in cash and $6.5 million applied to certain pre-payments from UOP), and to lease such equipment back to the Company (the sale of the property and simultaneous leaseback is referred to as a “sale-leaseback”). The lease term is for 7 years unless terminated early. During the lease term, the monthly lease payment from the Company to UOP is $186 thousand, which is split between a reduction of principal and interest expense using the effective interest rate of 11%.

The Company assessed the transaction in accordance with ASC 842, Leases, to determine whether it qualified as a sale and leaseback. However, because the underlying lease agreement met the qualifications to be classified as a finance lease, control of the equipment is not considered to be transferred to the buyer/lessor and thus the transaction does not qualify as a sale and leaseback under ASC 842. As such, the related financing obligation is accounted for in accordance with ASC 470, Debt.

On October 14, 2025, the Company entered into a promissory note agreement with YA II PN, Ltd. (“Yorkville”) for an aggregate principal amount of $40 million and an original issue discount of 8% (the “Promissory Note”). The Promissory Note was structured in two tranches, with the first tranche of $30 million (“Tranche 1”) drawn as of the date of the Promissory Note and the second tranche of $10 million (“Tranche 2”) available to be drawn until December 12, 2025.

The Promissory Note was subsequently amended to allow Tranche 2 to be drawn until February 28, 2026. The Company drew Tranche 2 on February 27, 2026, and signed a third amendment to the Promissory Note revising the

Tranche 2 repayment schedule to be payable in 12 periodic payments, with a final maturity date of February 27, 2027. The remaining terms and provisions of the Promissory Note were unchanged.

In connection with the Promissory Note, the Company issued common stock warrants to Yorkville (the “Yorkville Promissory Note Warrants”) which were deemed legally detachable and separately exercisable. See Note 11, Common Stock Warrants. The net proceeds of $36.5 million (after discount and issuance costs) were allocated between the Promissory Note and the Yorkville Promissory Note Warrants on the basis of relative fair value.

Early repayment is permitted. In the event of a default, the interest rate is increased to 18%. The effective interest rate on the outstanding balance and revised repayment schedule is 29%. Interest expense recognized on the Promissory Note during the three and six months ended June 30, 2026 was $2.6 million and $2.8 million, respectively. For the three months ended June 30, 2026, $0.1 million was attributable to contractual interest and $2.5 million to amortization of the discount on the Promissory Note. For the six months ended June 30, 2026, $0.1 million was attributable to contractual interest and $2.7 million to amortization of the discount. As of June 30, 2026, the net carrying amount of the Promissory Note and the associated discount were $4.6 million and $0.2 million, respectively.