Continuous lithium extraction from brine by efficient redox-couple electrodialysis

The rapid growth of lithium (Li)-ion batteries has catalyzed an unprecedented demand for Li. However, global Li supplies struggle to meet the ever-increasing demand because traditional Li mining processes are slow, expensive, and environmentally unsustainable. Here, we introduce an efficient redox-couple electrodialysis (RCE) approach for sustainable Li extraction from brine. The electrodialysis is driven by the same half-cell electrochemical reaction but operated in opposite directions—hydrogen evolution reaction and hydrogen oxidation reaction—which consumes minimal energy due to the zero-equilibrium full-cell voltage and the low overpotential. We demonstrate continuous Li extraction from brine for over 100 h, with a low operating voltage of 0.25 V, a faradaic efficiency of 88.87%, and a Li selectivity of 0.9954. Notably, the Li extraction via RCE consumes the specific energy of a mere 1.1 kWh kg_Li⁻¹, an order of magnitude lower than the energy demands of previously reported Li extraction techniques.