Lithium deposit under Arkansas could fix global EV battery problem

Oct 25, 2024

Arkansas may be home to a vast resource that could reshape the world's energy needs: a valuable battery component called lithium that's been nicknamed "white gold" and "the new gasoline."

It's an important discovery because renewable energy needs batteries and many batteries need lithium. But the resource is in short supply globally and especially in the United States.

A release this week from the U.S. Geological Survey suggests the U.S. might have all the lithium it needs in ancient brine which dates back to the Jurassic period and is buried deep below southern Arkansas.

There could be between 5 and 19 million tons of lithium buried there, enough to meet projected world demand for lithium car batteries nine times over, the USGS said in a statement.

The catch: figuring out how to extract that much lithium without wreaking havoc on the environment and the water table. Lithium is notoriously difficult to extract and has been linked to water depletion and other issues.

The discovery in Arkansas isn't unprecedented: Other nations also have vast, hard-to-reach deposits of lithium. But the location in Arkansas has already caught the eye of companies like Exxon that hope to develop practical ways to mine the valuable metal.

Lithium is a soft, silvery alkali metal that, in its pure form, is so reactive and flammable it has to be stored either in a vacuum or an inert gas like argon or an inert liquid like mineral oil.

It also happens to make fast-charging, high-energy-density and long-lifespan batteries, which is why lithium-ion batteries are used in cells phones, laptops, electric vehicles and for large energy storage systems.

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Unfortunately, it's also in short supply as the world shifts from burning fossil fuels for energy to carbon-neutral power sources like solar and wind. Utility-scale battery installations allow energy to be stored when the wind blows and the sun shines and used when people want it.

That's especially important in wind- and solar-rich areas like the U.S. "wind corridor" that runs from North Dakota and Montana southward to western Texas and for utility-scale solar power, where the resource is richest in the southeast and southwest.

Currently the U.S. relies on imports to supply about 25% of its lithium, according to the USGS. The nation has been working to expand domestic battery manufacturing as currently most such batteries come from China. Securing critical minerals, with lithium being one of the most important ones, is part of a federal strategy to protect U.S. manufacturing and supply chains.

Lithium is produced either from hard rock mines, clay mines or from ancient brines.

Arkansas is part of what's known as the Smackover Formation, a relic of a 200-million-year-old sea that covered parts of Arkansas, Louisiana, Texas, Alabama, Mississippi, and Florida. Parts of it have rich deposits of oil, but only recently was it realized that it also contains pockets where lithium is dissolved in highly salty waters deep underground.

Those lithium deposits lie under southern Arkansas and as drilling technologies have advanced, they have begun to become accessible. Now the problem is figuring out the technology to bring the brine to the surface and recover the lithium from it.

A USGS study published last month assessed those deposits.

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

She cautioned the estimates don't factor in what will be required to bring the lithium to the surface or extract it from the brines.

Lithium is expensive and rare in part because it is typically difficult to extract. In some areas extraction has been linked to water depletion and other issues.

Farmers in Nevada say lithium mines have emptied their wells from the underground freshwater aquifer. In February the U.S. Environmental Protection Agency said a lithium extraction project in California illegally drained 1,200 acres of fragile wetlands, according to a settlement agreement.

Exxon has already begun to explore of how it might reach Arkansas's lithium and develop technologies to remove it from the brine. It drilled its first lithium well there last year and said in a statement it aims to be a leading lithium supplier by 2030.