Standard Lithium Ltd. announced it has drilled and sampled, to the best of its knowledge, a new highest confirmed lithium grade brine in North America, with a grade of 663 mg/L lithium. The results reflect lithium sample analyses from a newly drilled well from the Company's significant expansion work in the East Texas Smackover region. The lithium sample analysis from a newly drilled well from The Company's significant expansion work in The East Texas Smackover region".

The Smackover Formation represents North America's premier lithium brine asset, with grades comparable to certain resources in South America. As detailed in the Company's Definitive Feasibility Study, results for the Phase 1A project in El Dorado, Arkansas, target 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. Lithium grades in the Company's projects indicate an increasing trend moving westward from Phase 1A to the South West Arkansas Project and finally, into East Texas. 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, comprised of 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.

The data provided in this news release are from a newly-drilled well completed in the East Texas Smack over (ETX New Well #2). Brine samples collected from ETX New Well #2 are provided in Table 1 below. These samples were analyzed, performed and reported by Western Environmental Testing Laboratories of Sparks, Nevada, a third-party, accredited testing facility.

Additional representative lithium brine analyses from other lithium brine projects in North America are provided for context. East Texas Sampling Location Name, Lithium concentration (mg/L), Average Lithium concentration (mg/L), ETX New Well #2, ETX New Well #2 - Upper Smackover Zone Sample B, 613, Reported Lithium Analyses from Other North American Brine Projects, California Salton Sea Geothermal Brine, 204, Alberta Oilfield Brine, 75, Paradox Basin, Utah, 123, Clayton Valley, Nevada, 123, Clayton Valley, California, 123.