Dr. Andy Robinson reports

STANDARD LITHIUM DELIVERS HIGHEST-EVER NORTH AMERICAN LITHIUM BRINE GRADE 806 MG/L; EAST TEXAS ASSET INCLUDES SIGNIFICANT POTASH AND BROMINE CONCENTRATIONS

Standard Lithium Ltd. has achieved another significant milestone in its continuing Smackover expansion efforts. As part of its extensive work in East Texas, the company has drilled and sampled a new highest confirmed lithium-grade brine, measuring 806 milligrams/litre. In addition, comprehensive brine analyses from all three of the company's new wells in East Texas show highly elevated concentrations of potash (KCl) and bromine, signifying a large potential for these commodities. The drilling work and continued resource evaluation are from areas where the company has secured the rights to all minerals contained in the brine.

Dr. Andy Robinson, president and chief operating officer of Standard Lithium, commented: "This most recent brine sample from our newest well in East Texas confirms the exceptional quality of the lithium brine assets we're acquiring in East Texas. With a new confirmed lithium analysis of 806 mg/L and an average grade of 644 mg/L in our drilled area, we believe that we have identified a globally significant lithium brine asset. This work has been made possible by our team of Smackover experts who, over the past three years, have identified the most prospective, highest-quality development areas in East Texas."

Dr. Robinson continued: "We understand that lithium grade is one of the most significant factors when considering the economics of a lithium brine project. We are committed to securing the highest-grade and potentially largest lithium brine resource outside of Argentina and Chile. Additionally, the highly elevated concentrations of potassium and bromine in all three of our new wells support our understanding that Standard Lithium now also controls a project with very large potash and bromine potential. While we continue to assess the potential value of these new discoveries, we believe that they could be accretive for the company and present significant additional upside."

Strategic importance

The Smackover formation represents North America's premier lithium brine asset, with grades comparable with certain resources in South America. As detailed in the company's definitive feasibility study, the Phase 1A project in El Dorado, Ark., contemplates average production of 5,400 tonnes per annum (tpa) of battery-quality lithium carbonate over a 25-year operating life, with an average lithium grade of 217 mg/L. The preliminary feasibility study for the company's South West Arkansas project outlines plans for at least 30,000 tpa of battery-quality lithium hydroxide over a 20-year operating life, with an average reported lithium grade of 437 mg/L.

Average lithium grades in the company's projects indicate an increasing trend moving westward from Phase 1A (217 mg/L) to the South West Arkansas project (437 mg/L) and finally, into East Texas (644 mg/L). In Standard Lithium's experience, higher lithium grades in brine are directly correlated with lower capital and operating expenses per tonne of lithium produced, thereby enhancing the economic viability of potential projects.

Analysis and testing details

The Standard Lithium team, comprising technically diverse Smackover specialists and a robust team of land professionals, has been working in the Smackover formation in East Texas for over 3.5 years. The company shared initial sample analysis from expansion work completed in the latter half of 2022 and early 2023, as well as more recent drilling data (see news release dated Oct. 10, 2023).

The data provided in this news release are from three recently drilled and sampled wells in the East Texas Smackover (ETX new wells No. 1, No. 2 and No. 3). The samples herein were analyzed and reported by Western Environmental Testing Laboratories of Sparks, Nev., a third party, accredited testing facility.

Quality person

Steve Ross, PGeol, a qualified person as defined by National Instrument 43-101, has reviewed and approved the relevant scientific and technical information that forms the basis for this news release. Mr. Ross is a consultant to the company.

About Standard Lithium Ltd.

Standard Lithium is a leading near-commercial lithium development company focused on the sustainable development of a portfolio of lithium-brine bearing properties in the United States. The company prioritizes brine projects characterized by the highest-grade resources, robust infrastructure, skilled labour 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, the Phase 1A project and the South West Arkansas project, are located on the Smackover formation in southern Arkansas near the Louisiana state line, a region with a long-standing and established brine processing industry. The company has also identified a number of highly prospective lithium brine project areas in the Smackover formation in East Texas and began an extensive brine leasing program in the key project areas. In addition, the company has an interest in certain mineral leases located in the Mojave Desert in San Bernardino county, California.

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