All-Component Recycling and Reuse Process for Spent LiFePO4 Cathodes

With the termination of the life of the first generation of power batteries, a substantial quantity of lithium iron phosphate (LiFePO₄) batteries necessitates recycling. The mainstream recycling process is lithium leaching with acid leaching systems and cathode material regeneration. However, the binder poly(vinylidene fluoride) (PVDF) and the conductive carbon in the cathode material are not utilized. In this paper, a new two-step recycling process is proposed: (1) an acid-free lithium leaching route using a single component K₂S₂O₈ as a leaching agent and (2) utilizing the residual carbon in the leaching residue to produce Fe₂P₂O₇, which can be used as anodes for batteries, by high-temperature carbothermal reduction of FePO₄. By optimizing the leaching process parameters, 98.9 wt % of the lithium in the cathode material can be selectively released. The electrochemical characteristics of Fe₂P₂O₇ synthesized at various carbothermal reduction temperatures were assessed, revealing that the sample produced at 700 °C exhibited the most favorable electrochemical attributes. Even after 750 cycles at a current density of 1.0 A/g, the catalyst retained a specific capacity of 160 mAh/g. This research introduces an innovative approach for the comprehensive recuperation of all components in recycling LiFePO₄.