The Natural State

Arkansas lithium deposits big enough to meet EV demand

Millions of years ago, a sea covered parts of what’s now Arkansas, Louisiana, Texas, Alabama, Mississippi, and Florida. What it left behind helped fuel the modern world. A century ago, oil was discovered in the Smackover Formation. Now, the amount of lithium held deep underground might be enough to power the EV transition.

Massive Amounts

The U.S. Geological Survey and Arkansas Department of Energy and Environment found that there are anywhere from 5 to 19 million tons of lithium in saltwater 10,000 feet below the surface of southwest Arkansas.

It remains to be seen how much of that is recoverable, but the deposits could be a massive game-changer as demand for lithium will quadruple by 2030 as EV sales continue to climb. Lithium demand is set to hit 1.5 million tons in 2025 and nearly 3 million by 2030, with nearly 90% of that going toward lithium-ion batteries for EVs.

Currently, Australia produces more than half of the world’s lithium, with most of that processed in China. The U.S. accounts for about 5% of the global supply, but that output would skyrocket if the Smackover deposits can be harvested.

“We estimate there is enough dissolved lithium present in that region to replace U.S. imports of lithium and more,” Katherine Knierim, the study’s principal researcher, said.

The researchers used machine learning to estimate the total amount of lithium in the brines in the area then analyzed samples at the USGS Brine Research Instrumentation and Experimental lab in Reston, Va. The ML model then used that information and geological maps to estimate lithium concentrations across the Smackover region.

“Lithium is a critical mineral for the energy transition, and the potential for increased U.S. production to replace imports has implications for employment, manufacturing and supply-chain resilience. This study illustrates the value of science in addressing economically important issues,” USGS director David Applegate said.

Extraction & Refinement

As part of its plan to transition to a new energy economy, ExxonMobil aims to start lithium production in the Smackover Formation in 2027. Exxon, which has the rights to 120,000 gross acres of the formation in Arkansas, says it will be able to use conventional oil and gas drilling techniques to get to the lithium-rich saltwater deposits deep underground.

It plans to separate the lithium from the water with direct lithium extraction (DLE) technology using solvents or filters rather than waiting for the water to evaporate. The water can then be reinjected into the reservoirs and the lithium converted onsite to battery-grade material.

“This landmark project applies decades of expertise to unlock vast supplies of North American lithium with far fewer environmental impacts than traditional mining operations,” Dan Ammann, president of ExxonMobil Low Carbon Solutions, said. “This project is a win-win-win. It’s a perfect example of how ExxonMobil can enhance North American energy security, expand supplies of a critical industrial material, and enable the continued reduction of emissions associated with transportation, which is essential to meeting society’s net-zero goals.”

Standard Lithium also has a fully integrated DLE process to extract lithium and produce battery-quality compounds. The company estimates it can produce 30,000 to 35,000 tons of lithium per year at its South West Arkansas Project.

“It is important to caution that these estimates are an in-place assessment,” USGS’s Knierim said. “We have not estimated what is technically recoverable based on newer methods to extract lithium from brines.”

The ancient waters beneath southwest Arkansas hold a staggering amount of lithium that could make the U.S. an EV-producing powerhouse, and there could be more in other states where the Smackover Formation extends. It might be enough to drive the course of the EV transition.