A Scalable Integrated Lithium Recovery from Spent LiFePO4 with Co-Production of Pure Hydrogen Powered by Renewables

Lithium supply chains are under immense pressure from the growing demand for lithium iron phosphate (LiFePO4)-based batteries. One way to address these pressure and curb environmental waste is to recover and reuse lithium from spent batteries. Electrochemical valorization offers a sustainable and green approach. However, current redox systems that couple lithium extraction with hydrogen production in alkaline electrolytes suffer from slow hydrogen evolution, sluggish lithium extraction, and low recovery efficiencies due to hydroxide ion (OH-) crossover. Here, we report a lithium extraction-cum-hydrogen production system that combines citric acid-based catholyte for hydrogen (H2) evolution and I3-/I- redox couple as anolyte for Li+ extraction. Unlike alkaline catholytes in current systems, citric acid boosted the H2 evolution potential, suppressed OH- formation, and ensured 100% lithium recovery efficiency. The proper redox potential and excellent electrochemical kinetics of the I3-/I- anolyte enabled rapid lithium extraction from LiFePO4 and lithium recovery at ampere-level current densities. We use the generated lithium citrate product as-is for the synthesis of new LiFePO4 materials. With solar energy integration, our fully green system combining renewable energy, lithium recycling, and green hydrogen production forms a zero-carbon closed-loop. A 5-kilogram prototype and cost-benefit analysis show the system is practical and profitable.