Construction of a Preoxidation and Cation Doping Regeneration Strategy to Improve Rate Performance Recycling Spent LiFePO4 Materials.

Efficient recycling of spent lithium-ion batteries (LIBs) is significant for solving environmental problems and promoting resource conservation. Economical recycling of LiFePO4 (LFP) batteries is extremely challenging due to the inexpensive production of LFP. Herein, we report a preoxidation combine with cation doping regeneration strategy to regenerate spent LiFePO4 (SLFP) with severely deteriorated. The binder, conductive agent, and residual carbon in SLFP are effectively removed through preoxidation treatment, which lays the foundation for the uniform and stable regeneration of LFP. Mg2+ doping is adopted to promote the diffusion efficiency of lithium ions, reduces the charge-transfer impedance, and further improves the electrochemical performance of the regenerated LFP. The discharge capacity of SLFP with severe deterioration recovers successfully from 43.2 to 136.9 mA h g-1 at 0.5 C. Compared with traditional methods, this technology is simple, economical, and environment-friendly. It provided an efficient way for recycling SLFP materials.