Mr. Daniel Rosen reports

SMACKOVER LITHIUM FILES MAIDEN INFERRED RESOURCE FOR ITS FRANKLIN PROJECT IN EAST TEXAS, CONTAINING THE HIGHEST REPORTED LITHIUM-IN-BRINE GRADES IN NORTH AMERICA

Smackover Lithium, a 55/45-per-cent-owned joint venture between Standard Lithium Ltd. and Equinor, has filed its maiden inferred resource report for the Franklin project in the northeastern region of Texas.

The Franklin project is highlighted by 2,159,000 metric tonnes of lithium carbonate equivalent at an average lithium concentration of 668 milligrams per litre, 15,414,000 tonnes of potash (as potassium chloride) -- a newly added mineral to the U.S. Geological Survey 2025 draft critical mineral list -- and 2,638,000 tonnes of bromide (ionized form of the commercial product bromine), contained within 0.61 cubic kilometre of brine volume.

The report for the JV's first project in the east Texas region of the Smackover highlights the size and quality of its brine position. Brine mineral leasing has been continuing since 2022 in the approximately 80,000-acre project area, with over 46,000 acres leased to support the inferred resource. The project also contains the highest reported lithium-in-brine grades in North America, including a previously measured 806 milligrams per litre at the Pine Forest 1 well (see news release dated Oct. 25, 2023).

This initial project definition marks a key step toward the ultimate goal of reaching production of over 100,000 tonnes of lithium chemicals per year in Texas through multiple phases. This goal is further supported by two additional projects that the JV is planning to develop in east Texas that are anticipated to roughly triple the size of the JV's portfolio area in the state.

The principal recommendation for next steps is to further refine the characteristics of the Upper and Middle Smackover formation aquifers and brine chemistry and to assess reserve forecasts. This will be accomplished by drilling additional appraisal wells and re-entering three shut-in wells to facilitate the definition of a preliminary feasibility study.

The JV will also conduct direct lithium extraction testing of the project brine, leveraging insights gained from Standard Lithium's demonstration plant located in El Dorado, Ark., as well as the JV's southwestern Arkansas project.

The report is available for review under the company's profile on SEDAR+ and on the company's website. For highlights of this report, please refer to the company's press release dated Sept. 24, 2025.

Qualified person

All scientific and technical disclosure in this news release was reviewed and approved by Stephen Ross, PGeo, British Columbia, vice-president of resource development for Standard Lithium, a qualified person for purposes of, and as that term is defined in, National Instrument 43-101 (Standards of Disclosure for Mineral Projects). Mr. Ross is not independent of the company.

About Smackover Lithium

Smackover Lithium is a joint venture between Standard Lithium and Equinor. Formed in May, 2024, Smackover Lithium is developing multiple DLE projects in southwestern Arkansas and east Texas. Standard Lithium owns a 55-per-cent interest, and Equinor holds the remaining 45-per-cent interest in the JV projects, with Standard Lithium maintaining operatorship.

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 projects characterized by high-grade resources, robust infrastructure, skilled labour and streamlined permitting. Standard Lithium aims to achieve sustainable, commercial-scale lithium production through the application of a scalable and fully integrated DLE 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, Standard Lithium is advancing the southwestern Arkansas project, a greenfield project located in southern Arkansas, and actively advancing a promising lithium brine resource position in east Texas.

Standard Lithium trades on both the TSX Venture Exchange and the NYSE American under the symbol SLI.

About Equinor

Equinor is an international energy company committed to long-term value creation in a low-carbon future. Equinor's portfolio of projects encompasses oil and gas, renewables, and low-carbon solutions, with an ambition of becoming a net-zero energy company by 2050. Headquartered in Norway, Equinor is the leading operator on the Norwegian continental shelf and has offices in more than 20 countries worldwide. Equinor's partnership with Standard Lithium to mature DLE projects builds on its broad U.S. energy portfolio of oil and gas, offshore wind, low carbon solutions, and battery storage projects.

We seek Safe Harbor.