Direct regeneration of spent LiFePO4 cathode materials with pre-oxidation and V-doping

Direct regeneration has been widely applied in recovery of LiFePO4 batteries. However, excess residual carbon and inherent low electronic and ionic conductivity of spent LiFePO4/C cathode materials lead to the reduction of electrochemical performance. Herein, a facile and simple regeneration process of pre-oxidation and vanadium doping is developed to regenerate LiFePO4/C cathode materials. Pre-oxidation was applied to remove excess carbon at 500 °C for 3 h in air. Vanadium doping was applied to improve electronic and ionic conductivity of regenerated cathode materials. Among the regenerated cathode materials, the 3 mol% V doped sample possesses discharge capacity of 134.3 mAh/g after 200 cycle at 1C with the discharge capacity retention of 99.1%. At 2, 5, 10C, the discharge capacities are 134, 124.1, 111.5 mAh/g, respectively. The vanadium doping regeneration process with oxidation pre-oxidation is simple, and feasible to be applied in the recovery of spent LiFePO4 cathode materials.