In 2021, the U.S. Department of Energy launched a competition designed to stimulate creative thinking about an important societal challenge, and hundreds of competitors jumped in for a chance at the $1 million first prize. A few weeks ago, the winners were announced—and that $1M prize went to a team led by UIUC’s Paul Braun, with UIUC’s Beniamin Zahiri contributing key expertise and Xerion Advanced Battery Corp. as an industry partner.
Lithium is essential to modern life, as it’s the foundation of the batteries that power everything from laptops and smartphones to electric vehicles. Today, the U.S. sources 1% of its lithium supply from a single site in Nevada; the other 99% is imported, much of it through China. Such near-total dependence on foreign sources, for such a critical material, is seen as a national vulnerability.
The problem isn’t that lithium sources haven’t been found in the U.S.; far from it.
“Lithium is really everywhere,” explains Braun, who is a Grainger Distinguished Chair in Engineering, a professor of materials science & engineering and chemistry, and the director of the Materials Research Laboratory (MRL). “You find it in the earth and you find it in the ocean.”
The problem, he says, is that it’s generally found only in very low concentrations. Even in California’s Salton Sea region, where the “geothermal brines”—hot, mineral-rich waters from deep below the Earth’s surface—are believed to have the highest lithium concentrations of any brines in the world, the concentration is still only around 300 parts per million. So what’s an economical and environmentally friendly way to extract it?
According to the prizewinning design, the solution is “basically to do what normally happens in a battery, but through a membrane,” says Zahiri, who is a research assistant professor in MRL.
On a daily basis, most of us run our phones’ batteries down by using them, and we recharge the phones by plugging them into their chargers. The essence of that discharging and recharging is the movement of lithium ions that are being pushed in and out—and the winning team’s core idea was to “do exactly the same concept but within a different engineering design format,” as Zahiri puts it.
The team designed a ceramic membrane that can be thought of as “a material that lithium ions fit in,” says Braun. When given the right electrical bias, it will pull in lithium ions from the adjoining brine; then, when given the opposite voltage, it will push the lithium ions back out on the other side of the membrane, effectively extracting the lithium from the brine.
The team anticipates that the technology will one day be used at power plants that are already pulling up geothermal brines for the purpose of energy production. One of the beauties of the proposed solution is that it would piggyback on the power plants’ activities and add almost no extra environmental impact.
“There’s an opportunity if you can sit at the end of a geothermal plant, which has a lot of brine flowing through it all day, and they’ve already paid to pull it out of the earth and re-inject it,” says Braun. The lithium extraction would simply be a final step before the used brine goes back in the ground.
The DOE’s prize-based funding mechanism was unusual, and one of its remarkable features was the consultants provided by the organizers. These industry experts interacted with the contenders throughout the competition, with more and deeper involvement as participants advanced through rounds of competition.
Braun describes it as an “iterative learning process” that refined and shaped the team’s ideas, leading to a “much better final pitch” than the team could have achieved on its own.
“The organizers deserve a lot of credit” for the team’s successful outcome, he believes.
The $1 million prize will enable them to build a prototype device that can be tested against real brines. If the prototype is successful, commercial development may be the next step.