Highly selective leaching of lithium via the synergistic effect of lactic acid and hydrogen peroxide

The large-scale use of lithium iron phosphate (LFP)-based lithium-ion batteries has raised increasing challenges in environmental protection and resource recovery. This study investigated the feasibility of recovering spent LFP using lactic acid assisted by hydrogen peroxide, aiming to develop an efficient, mild, and economically viable recycling process. The leaching performance of five organic acids was compared, and the results showed that the lactic acid-hydrogen peroxide system exhibited excellent selectivity for lithium extraction. Under the optimized conditions of 0.2 mol/L lactic acid, 2.5% H₂O₂ (vol.%), and water-bath heating at 25 °C for 30 min, the lithium leaching efficiency reached 99.4%, while the residue could be further treated to obtain high-purity iron phosphate. Kinetic analysis suggested that the leaching process was jointly controlled by surface chemical reaction and internal diffusion. High-purity lithium carbonate was recovered from the leachate through concentration and precipitation.A preliminary EverBattery-based assessment showed that the proposed route reduced total energy consumption and greenhouse gas emissions compared with conventional sulfuric acid-based hydrometallurgy, indicating its potential as an efficient and environmentally favorable recycling strategy for spent LFP batteries.