6-K

UNITEDSTATES

SECURITIESAND EXCHANGE COMMISSION

Washington,D.C. 20549

FORM 6-K

Reportof Foreign Private Issuer Pursuant to Rule 13a-16 or 15d-16

ofthe Securities Exchange Act of 1934

Indicate by check mark whether the registrant files or will file annual reports under cover of Form 20-F or Form 40-F:

Form 20-F ¨ Form 40-F x

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(1): ¨

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(7): ¨

DOCUMENTS INCLUDEDAS PART OF THIS REPORT

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

Exhibit 99.1

FORM 51-102F3

MATERIAL CHANGE REPORT

Electra Battery Materials Corporation. (the “Company”)

133 Richmond Street W, Suite 602

Toronto, Ontario

M5H 2L3

February 27, 2024

The Company issued a news release on February 27, 2024 relating to the material change, which was disseminated through Business Wire and subsequently filed on SEDAR+.

The Company announced that the Company and the holders (the “Noteholders”) of US$51 million principal amount of 8.99% senior secured convertible notes (the “Notes”) entered into an agreement (the “Waiver”) whereby the Noteholders have agreed, subject to certain conditions, to a postponement in the unpaid payment of interest on the Notes payable on the August 15, 2023 and February 15, 2024 interest payment dates (the “Interest”) under the convertible note indenture dated as of February 13, 2023 (the “Indenture”) that governs the Notes.

The Company and the Noteholders entered into the Waiver whereby the Noteholders have agreed, subject to certain conditions, to a postponement in the unpaid payment of Interest on the Notes payable on the August 15, 2023 and February 15, 2024 interest payment dates under the Indenture that governs the Notes. Pursuant to the Waiver, the Company is required to make payment of accrued Interest on August 15, 2024, other than the Interest to be paid through the Share Issuance (as defined below). In the event of a default by the Company under the Indenture, the Company is required to pay the Interest immediately. Pending repayment, the Interest will be treated as additional principal amounts of Notes entitled to the same rights as the Notes under the Indenture, including the accrual of additional interest under the Indenture and the right to convert into common shares in the capital of the Company (“Common Shares”).

The Company has agreed to satisfy US$400,732 of the Interest through the issuance of Common Shares to certain Noteholders (the “Share Issuance”). The Share Issuance will occur at a deemed value equivalent to 95% of the volume weighted average trading price of the Common Shares for the five trading days immediately prior to the issuance. The Share Issuance remains subject to the approval of the TSX Venture Exchange (the “TSXV”), and the Company will issue a further news release once the Share Issuance has been completed confirming the final number of Common Shares issued.

In addition, subject to certain conditions, the Noteholders have agreed to waive the requirement set out in the Indenture for the Company to file a registration statement to provide for the resale of the Common Shares underlying the Notes and the common share purchase warrants issued on February 13, 2023.

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Not applicable. This report is not being filed on a confidential basis.

Not applicable

The following executive officer of the Company is knowledgeable about the material change and this report:

Trent Mell

Chief Executive Officer

Telephone: 416 900-3891

February 27, 2024

Cautionary Note Regarding Forward-Looking Statements

This report may contain forward-looking statementsand forward-looking information (together, “forward-looking statements”) within the meaning of applicable securities lawsand the United States Private Securities Litigation Reform Act of 1995. All statements, other than statements of historical facts, areforward-looking statements. Generally, forward-looking statements can be identified by the use of terminology such as “plans”, “expects”, “estimates”, “intends”, “anticipates”, “believes” or variationsof such words, or statements that certain actions, events or results “may”, “could”, “would”, “might”, “occur” or “be achieved”. Such forward-looking statements include, without limitation, statements regarding completionof the Share Issuance and the postponement of the Interest. Forward-looking statements are based on certain assumptions, and involve risks,uncertainties and other factors that could cause actual results, performance, and opportunities to differ materially from those impliedby such forward-looking statements. Among the bases for assumptions with respect to the potential for additional government funding arediscussions and indications of support from government actors based on certain milestones being achieved. Factors that could cause actualresults to differ materially from these forward-looking statements are set forth in the management discussion and analysis and other disclosuresof risk factors for Electra Battery Materials Corporation, filed on SEDAR+ at www.sedarplus.com and with on EDGAR at www.sec.gov. Otherfactors that could lead actual results to differ materially include changes with respect to government or investor expectations or actionsas compared to communicated intentions, and general macroeconomic and other trends that can affect levels of government or private investment.Although the Company believes that the information and assumptions used in preparing the forward-looking statements are reasonable, unduereliance should not be placed on these statements, which only apply as of the date of this report, and no assurance can be given thatsuch events will occur in the disclosed times frames or at all. Except where required by applicable law, the Company disclaims any intentionor obligation to update or revise any forward-looking statement, whether as a result of new information, future events or otherwise.