A research team led by the George Washington University’s Xitong Liu is one of three winners of the U.S. Department of Energy’s first-ever American-Made Geothermal Lithium Extraction Prize. The prize funds new technologies that efficiently extract the in-demand element from geothermal wastewater. Liu’s team, Ellexco, won $500,000 for its chemical-free extraction process.
“We were really honored to be recognized by the Department of Energy, and we hope we can use this opportunity to further improve our technology,” said Liu, an assistant professor of civil and environmental engineering in the School of Engineering and Applied Science.
If you’ve used a cell phone, read an e-book, logged steps on a smart watch, cruised down K Street on a scooter, or brushed your teeth with an electric toothbrush, you’ve almost certainly used lithium-ion battery power to do it. Lithium’s light weight and high conductivity make it ideal for use in rechargeable batteries for personal devices, and demand for that purpose has skyrocketed in the past decade. But the United States imports the vast majority of its lithium, and the element is traditionally extracted via environmentally harmful mining operations.
One possible solution is to extract lithium from the wastewater produced by geothermal power plants, known as geothermal brine. According to the DOE, developing brine extraction methods will not only ensure a strong domestic lithium supply chain but also create jobs and grow the renewable energy infrastructure.
The team's technology is chemical-free, meaning it has a lower environmental impact than many alternatives. It involves an electrode material that is highly selective to lithium ions. When an electric current is applied to geothermal brine, ions—including not just lithium, but abundant elements like sodium and calcium—are attracted to the electrode material, which retains only the lithium and discards the rest.
“This technique lets us pull lithium out of the solution without many impurities,” Liu said.
The DOE award will allow Liu and his team to continue refining their technology, to scale up their prototypes and perhaps to begin pilot testing at California’s Salton Sea, a lake lined by 11 geothermal power plants that is the country’s largest source of geothermal brine. Liu said the Salton Sea could contain enough lithium to power over 50 million electric vehicles, helping move the country toward the Biden-Harris administration’s goals of 50% electric vehicle adoption by 2030 and a net-zero emissions economy by 2050.
“We need to develop new sources of lithium, and we need better technologies to access them,” Liu said. “That’s where our technology comes into play.”
