Preoxidation and Prilling Combined with Doping Strategy to Build High-Performance Recycling Spent LiFePO₄ Materials

Direct regeneration has gained much attention in LiFePO₄ battery recycling due to its simplicity, ecofriendliness, and cost savings. However, the excess carbon residues from binder decomposition, conductive carbon, and coated carbon in spent LiFePO₄ impair electrochemical performance of direct regenerated LiFePO₄. Herein, we report a preoxidation and prilling collaborative doping strategy to restore spent LiFePO₄ by direct regeneration. The excess carbon is effectively removed by preoxidation. At the same time, prilling not only reduces the size of the primary particles and shortens the diffusion distance of Li⁺ but also improves the tap density of the regenerated materials. Besides, the Li⁺ transmission of the regenerated LiFePO₄ is further improved by Ti⁴⁺ doping. Compared with commercial LiFePO₄, it has excellent low-temperature performance. The collaborative strategy provides a new insight into regenerating high-performance spent LiFePO₄.