File: '\\swfile\EmailIn\20250411 160346 Attachment SLI - Press Release re Q1 2025 ATM.docx'

LEGAL*61338549.1

STANDARD LITHIUM PROVIDES QUARTERLY ATM SALES UPDATE

VANCOUVER, BC, April 11, 2025 - Standard Lithium Ltd. ("Standard Lithium" or the "Company") (TSXV: SLI) (NYSE American: SLI), a leading near-commercial lithium company, today provided a quarterly update with respect to the Company's previously announced "at-the-market" equity program (the "ATM Program") launched on November 17, 2023. The ATM Program allows the Company to issue and sell, from time to time, up to US$50,000,000 (or the Canadian dollar equivalent) of its common shares ("Common Shares") from treasury to the public, at the Company's discretion, pursuant to a sales agreement (the "Sales Agreement") between the Company, Citigroup and Canaccord Genuity (collectively, the "Agents").

During the quarterly period ended March 31, 2025, the Company issued a total of 281,900 common shares on the TSX Venture Exchange (the "TSXV") at an average price of C$2.25 per share and 4,289,470 common shares on the NYSE American LLC (the "NYSE American") at an average price of US$1.56 under the ATM Program, providing gross proceeds of C$633,409 and US$6,705,092, respectively. Commissions of C$15,835 and US$167,627 were paid to the Agents, in relation to these distributions.

About Standard Lithium Ltd.

Standard Lithium is a leading near-commercial lithium development company focused on the sustainable development of a portfolio of large, high-grade lithium-brine properties in the United States. The Company prioritizes brine projects characterized by high-grade resources, robust infrastructure, skilled labor, and streamlined permitting. The Company aims to achieve sustainable, commercial-scale lithium production via the application of a scalable and fully integrated direct lithium extraction and purification process. The Company's flagship projects are located in the Smackover Formation, a world-class lithium brine asset, focused in Arkansas and Texas. In partnership with global energy leader Equinor ASA, the Company is advancing the South West Arkansas project, a greenfield project located southern Arkansas, and actively exploring promising lithium brine prospects in East Texas. The Company also holds an interest in certain mineral leases in the Mojave Desert in San Bernardino County, California.

Standard Lithium trades on both the TSXV and the NYSE American under the symbol "SLI".

Neither the TSXV nor its Regulation Services Provider (as that term is defined in policies of the TSXV) accepts responsibility for the adequacy or accuracy of this release.

Investor and Media Inquiries

Chris Lang

Standard Lithium Ltd.

investors@standardlithium.com

+1 604 409 8154