Lithium Brine Breakthrough Or Not, Thacker Pass Is Happening – CleanTechnica

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The Intertubes have been buzzing over a new lithium brine extraction system aimed at satisfying the growing demands of the EV battery supply chain, without the environmental baggage carried by lithium mines. That should help the EV makers of the future avoid tarnishing their green reputation with controversial mining projects. As for the present, all systems are still go for the Thacker Pass mine in Nevada.

Environmentally Friendly Lithium From Geothermal Brine

Lithium is practically everywhere. It’s in seawater, for example. However, the concentration in seawater is extremely low. The US Department of Energy is among those seeing much more promise in the salty brines that come with geothermal energy systems.

“Geothermal brines often have high concentrations of minerals like lithium, salt, and zinc,” the Energy Department points out.

In addition to providing an alternative lithium supply pathway, a new geothermal brine extraction industry in the US would help support an increase in the nation’s fleet of geothermal energy projects, adding more resiliency to the nation’s clean power profile.

Though geothermal extraction systems require some surface infrastructure, they deploy relatively compact electrochemical systems and they don’t require the sprawling lagoons typical of other lithium recovery methods.

The Long Road To Geothermal Lithium Extraction

There being no such thing as a free lunch, scaling up geothermal extraction and pushing down costs have posed significant obstacles to widespread commercial use. Electrochemical systems are challenging because the natural brines associated with geothermal projects are loaded with substances similar to lithium, including sodium and potassium. Weeding them out requires more energy and more chemical inputs, resulting in increased costs.

In addition, conventional electrochemical systems produce chlorine gas as a hazardous byproduct, further adding the expense of safety systems and mitigation.

In an effort to spur market-oriented innovation in the field, back in 2021 the Energy Department’s Geothermal Technologies Office launched the “American-Made Geothermal Lithium Extraction Prize.” The following year, five teams qualified to participate in the third and final round of the program. The list included George Washington University, Rice University, the University of Illinois Urbana-Champaign, the University of Utah, and the University of Virginia.

The Rice University Breakthrough

Rice and the University of Utah got knocked out in the third round last year, but that was not an end to the DLE research. The new breakthrough comes from a Rice team headed up by researchers Lisa Biswal and Haotian Wang, in a project funded partly by the Energy Department’s Office of Energy Efficiency and Renewable Energy.

The Biswal-Wang team developed a three-chamber reactor, with the middle chamber deploying a solid, but porous, electrolyte. The arrangement blocks unwanted ions and reduces the opportunity for chlorine gas to form, while enabling lithium to pass through.

The team’s study was published in the journal PNAS on November 11 under the title, “Three-chamber electrochemical reactor for selective lithium extraction from brine.”

“The key component that enables highly selective lithium extraction lies in the specialized lithium-ion conductive glass ceramic (LICGC) membrane on the other side of the electrolyzer, which selectively allows lithium to pass through while blocking other ions,” Rice University explains.

“The LICGC membrane’s high ionic conductivity and selectivity are crucial for maintaining efficiency as it significantly reduces the interference from the other ions present in natural brines such as potassium, magnesium and calcium,” the school adds.

The research team also reported a lithium purity rate of 97.5%, making it a suitable precursor for the lithium hydroxide..

Next Steps For The EV Battery Supply Chain

If the use of a glass-type ceramic membrane sounds familiar, that’s no accident. As Rice notes, this type of material has emerged as a fixture in new solid-state lithium-ion batteries.

The next steps for the research include making the system more energy efficient. That means finding a way to prevent sodium ions from building up on the surface of the glass ceramic membrane. Surface coatings and adjustments to the current are among the strategies the team plans to pursue.

So, it will be a while before the new three-chamber system makes it way to the market. In the meantime, the Energy Department has a number of other R&D irons in the fire related to the extraction field. Another brine-related area to keep an eye on consists of piggybacking on brine from oil and gas operations (see more background on the lithium and geothermal brine connection here).

The US also has copious reserves of subsurface lithium waiting to be mined, and the Biden-Harris administration is determined to plug a gaping hole in the domestic EV battery supply chain sooner rather than later. The new Thacker Pass mine has emerged as a high profile supply chain showpiece project for the administration. Its developer, Lithium Nevada Corp., just nailed down a $2.26 billion loan from the Energy Department to establish a lithium processing facility next to the site. Once up and running, the mine-plus-processing combo is expected to yield 40,000 tonnes [a little over 44,000 US tons] per year.

“Lithium carbonate from Thacker Pass could support the production of batteries for up to 800,000 EVs annually, avoiding the consumption of 317 million gallons of gasoline per year,” the Energy Department emphasizes.

Of course, there are other ways to avoid consuming gasoline without putting an electric car in every garage or destroying large swaths of natural habitat and cultural heritage sites. Investing more state and federal resources in electric bus fleets and rail systems is one way to do that. Providing (or restoring) more opportunities for remote work is another. Ensuring that every community has access to basic commodities without hopping in and out of a car would also help, though that requires hammering out some sticky socioeconomic issues.

Recirculating used lithium through the automotive ecosystem is another way to avoid unnecessary mining. Extracting lithium from a spent EV battery is no easy task, but the US battery recycling industry is beginning to kick into gear.

A new generation of non-lithium EV battery formulas will eventually alleviate the pressure on mining, too. For the here and now, though, EV sales are continuing to grow alongside demand for stationary energy storage applications. New mines like  Thacker Pass will have plenty of off-takers waiting in line for their share.

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Image: New lithium mines will plug a gaping hole in the US EV battery supply chain until more sustainable, alternative sources emerge (courtesy of US DOE).