Oxidation-CO2 leaching of spent LiFePO4 for lithium extraction and impurity control

Abstract

Lithium iron phosphate (LiFePO₄ or LFP) is a critical cathode material in electric vehicle batteries, although its recycling is constrained by limited economic feasibility. This study proposes an innovative H₂O₂–CO₂ leaching strategy for the selective extraction of lithium from spent LFP batteries. This approach operates at ambient temperature and pressure, delivering a straightforward process with high leaching efficiency. Optimal conditions yield a lithium leaching efficiency greater than 94%, with kinetic analysis indicating that the process is primarily controlled by solid layer diffusion. For impurity control, iron and phosphorus are removed by high-temperature treatment, and copper is effectively removed using an electrochemical method, resulting in a high purity of more than 99.6% of the Li₂CO₃ product. Life cycle assessment highlights the substantial reductions in energy consumption and greenhouse gas emissions, alongside notable economic advantages of this process. This approach is a promising, sustainable, and economically advantageous solution for recycling spent LFP batteries and has substantial application potential.