Structural Restoration of Degraded LiFePO₄ Cathode with Enhanced Kinetics Using Residual Lithium in Spent Graphite Anodes

Enormous LiFePO4 (LFP)/graphite batteries retired from the market need urgent rational disposal and reutilization based on the degradation analysis of the evolutional mechanism for electrodes. Typically, Li inventory loss is one of the main reasons for the degradation of LFP-based batteries. The reduced portion of lithium in a cathode is inevitably consumed to form solid electrolyte interphase or trapped in the anode. Herein, we propose a comprehensive strategy for battery recycling and conduct the work by simply regenerating the degraded LFP materials directly with the extracted lithium compounds from spent anodes. Moreover, inter-particle three-dimensional (3D) conductive networks are built via an in situ carbonization to reinforce the electronic conductivity of regenerated cathodes. An improved electrochemical performance was achieved in the regenerated LFP materials even compared with the pristine LFP. This integrated recycling strategy not only brings more added value to the recycled materials by leveraging the recycling process but also aims to apply the concept of "treating waste with waste" and spur innovations in battery recycling technologies in the future.