Exxon Mobil plans to decide by the end of the year which lithium filtration technology it will use in Arkansas as part of its push to become one of the world's top producers of the battery metal, an executive said on Thursday.

The company last fall announced its long-anticipated plan to filter lithium from the Smackover brine formation that flows under Arkansas, with the aim of producing enough of the metal by 2030 to power one-million electric vehicle (EV) batteries.

The plan will require a complex mix of equipment, including at least one of a so-far unproven fleet of direct lithium extraction (DLE) technologies to filter the metal from the brine.

Exxon has built a pilot plant in Houston and spent recent months testing various DLE technologies, producing small amounts of battery-grade lithium, Patrick Howarth, head of Exxon's lithium business, said in an interview on the sidelines of the Arkansas Lithium Innovation Summit in Little Rock.

Howarth, who has worked at Exxon for nearly 19 years, said the facility allows the company to test how the DLE processes interact with the rest of the vast network of equipment needed for production.

"DLE is a small part of a really complicated process that has many different steps," said Howarth. "We're really focused on how do they interact with one another."

Lithium production with partner Tetra Technologies is expected to begin in Arkansas by 2026, and by 2027 from roughly 48 562 ha Exxon owns independently.

Exxon has had early discussions with automakers about purchasing lithium, but no agreements have been made, Howarth said.

"What we've seen, especially following the announcement in November, is a very real strong pull for the projects and ultimately the (lithium) product that we're bringing to market," he said.

Exxon and Tetra's agreement to develop roughly 6,100 acres in Arkansas is part of a memorandum of understanding that both companies said they are working to finalize.