Environmentally friendly recycling and effective repairing of cathode powders from spent LiFePO4 batteries

Abstract

Extensive use of LiFePO₄ batteries will afford a lot of spent LiFePO₄ batteries, which cannot be recycled properly by using traditional processes at present. If these spent LiFePO₄ batteries are thrown away without recycling properly, it is not only a severe waste of valuable resources, but also leads to serious environmental pollution. In this paper, a completely green recycling process and a small scale model line are developed to recycle cathode powders from spent LiFePO₄ batteries for the first time. Parts of LiFePO₄ host particles in spent LiFePO₄ batteries decompose to FePO₄, Fe₂O₃, P₂O₅ and Li₃PO₄ after numerous charge–discharge cycles, resulting in poor electrochemical performance of freshly recycled cathode powders for Li-ion batteries. To repair decomposed LiFePO₄ host particles, recycled cathode powders are heat-treated at different temperatures. After heat-treatment at high temperatures, especially at 650 °C, cathode powders are effectively recycled and can be reused for Li-ion batteries.