Accidental discovery separates lithium from brines without electricity

Researchers at the University of Michigan have discovered a novel, electricity-free membrane method to extract lithium from magnesium-rich brines, which were previously considered uneconomical for lithium recovery. Traditional lithium extraction from brines relies on evaporation ponds and chemical treatments to separate lithium from magnesium, but high magnesium concentrations complicate this process, increasing costs and environmental impact. The new approach uses a negatively charged membrane with pure water on one side and brine on the other, allowing lithium ions to pass through while magnesium ions are trapped, due to their strong binding to the membrane’s negative charges. This unexpected behavior contrasts with conventional electrodialysis, where magnesium ions typically move faster because of their higher charge. This discovery could unlock vast lithium resources trapped in magnesium-rich waters, such as those in the Smackover Formation in Arkansas, helping to meet the growing demand for lithium driven by batteries, electric vehicles, and renewable energy systems. However, the method cannot separate lithium from ions with the same charge, like sodium, so