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

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.