A new method to extract lithium from salty brines is more efficient and sustainable than current methods. The technology also costs less than half of today’s methods. That could bring down the cost of extracted lithium to less than a quarter of the metal’s current market price, according to a study published in the journal Matter.
Batteries are going to be necessary for electrifying the world’s transportation systems and for storing renewable electricity on the grid. But producing lithium for batteries is a slow, expensive process that takes a huge toll on the environment.
Lithium producers currently mine the metal by evaporating lithium salt-laced brines in giant ponds. This takes a year, requires a lot of land, and generates waste.
Researchers and several companies are now starting to use a technology called direct lithium extraction. These methods use special materials that selectively soak up lithium.
But there is a new kid on the DLE block based on electrochemical methods. One of those is electrodialysis, which involves transporting ions through a lithium-selective membrane using an applied electric field.
Yi Cui and colleagues at Stanford University have now come up with a new kind of electrodialysis technique. In their reactor, two opposite reactions happen on the two sides of the membrane: hydrogen evolution on one side and hydrogen oxidation on the other.
The reactions result in lithium ions moving through the membrane, creating a higher lithium concentration on the hydrogen evolution side. By connecting several reactor cells in a series, the lithium concentration goes up enough to extract the metal.
The researchers demonstrated continuous lithium extraction from brine for over 100 hours. The method has a lithium selectivity of 100%, and uses only a tenth of the electricity of today’s extraction methods. And, say the researchers, the approach should cost about $3,500 – $4,400 per ton of lithium from brine, while today’s typically costs about US$9,100.
Source: Rong Xu et al. Continuous lithium extraction from brine by efficient redox-couple electrodialysis. Matter, 2024.
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