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Spotted: Lithium plays a key role in the net-zero transition, with lithium-ion batteries used in everything from electric cars to renewable energy storage. But lithium isn’t an unlimited resource, and its extraction currently comes with land degradation and mass pollution. Luckily, a new method developed by researchers at Stanford University’s School of Engineering could change that.

Traditional lithium extraction relies on massive evaporation ponds, where salty liquid (brine) from the earth is left to evaporate, leaving behind elements like lithium. This is an extremely slow process and requires the use of toxic chemicals to further separate out the lithium. Instead, the Stanford scientists, including senior author of the study Professor Yi Cui, are turning to a technology called ‘redox-couple electrodialysis’ (RCE).

This process, powered by electricity, involves moving brine through a solid-state electrolyte membrane, which purifies it from a liquid with low lithium concentration to a more concentrated and high-purity solution. Because the technology doesn’t require huge brine ponds, it has a significantly smaller water and land footprint and could be implemented across a wider variety of geographies than is currently possible with lithium extraction sites. And, as well as being extremely efficient, RCE is more cost-effective than existing technologies, using fewer chemical agents and less electricity.

The new method works with liquids of varying concentrations of lithium, potassium, and sodium and could also be used to extract lithium from the wastewater generated during oil production. In future, it could even be used to extract the mineral from seawater, which hasn’t yet been feasible on a commercial scale. For now, the researchers are optimising the system to enable faster extraction, including by testing different materials for the membrane.

Written By: Matilda Cox