Sustainable Regeneration of Spent LiFePO4 Cathode with Al-Doping

With the popularity of electric vehicles, the number of used lithium iron phosphate (LiFePO 4 , LFP) batteries has increased significantly, and failure to properly dispose of these end-of-life power batteries will cause serious harm to the environment. In this study, an environmentally friendly and efficient solid-phase method is proposed to regenerate spent LFP cathode materials. In this method, the crystal structure of LFP cathode materials is restored by supplementing lithium using a lithium source, Fe 3 + impurities in LFP are reduced using glucose, and the regenerated materials are carbon coated. In addition, Al 3 + is introduced to dope the regenerated LFP to further enhance its repair effect. The test results show that the Al 3 + -doped regenerated LFP material has a low electrochemical impedance, and its discharge-specific capacity reaches 148.59 mAh g −1 at a 0.05 C multiplication rate, which is about 93.38% of the discharge-specific capacity of the new LFP (N-LFP). The capacity retention rate reaches 89.02% after 500 cycles at 1 C multiplication rate. These data indicate that the doped and regenerated LFP material exhibits an excellent capacity recovery rate and cycling stability. This study provides a new route for the recycling of waste LFP cathode materials.