Continuous Lithium Extraction from Brine by Highly Efficient Redox-Couple Electrodialysis

The rapid growth of lithium ion batteries has catalyzed an unprecedented demand for lithium. However, global Li supplies struggle to meet the ever-increasing demand because traditional Li mining processes are slow, expensive, inefficient, and environmentally unsustainable. Here, we introduce a highly efficient redox-couple electrodialysis (RCE) approach for sustainable Li extraction from brines. In our design, the electrodialysis is driven by the same half-cell electrochemical reaction but operated in the opposite directions: hydrogen evolution reaction and hydrogen oxidation reaction, which consumes minimum energy due to the zero equilibrium full-cell voltage resulted from the nature of the same half-reactions and their low overpotential. Meanwhile, the adoption of solid-state electrolytes as Li-ion selective membranes ensures high selectivity of the Li extraction from brines with mixed ions. We demonstrate a continuous Li extraction from brines for over 100 hours, with an low operating voltage of around 0.25 V, a Faradaic efficiency of 88.87%, and a Li selectivity of 99.54%. Notably, the Li extraction via RCE consumes the specific energy of a mere 1.1 kWh per kilogram of Li, approximately an order of magnitude lower than the energy demands of most reported Li extraction techniques. Techno-economic analysis reveals that Li extraction via RCE offers a substantially reduced cost compared to the traditional Li extraction technique. The efficiencies and cost benefits innate to our RCE approach not only position it as a promising alternative to prevailing Li extraction techniques but also as a potential catalyst to reshape the lithium supply chain.