Regeneration Strategies of Spent LiFePO ₄ Batteries: Dual Routes of Decomposition and Repair Dominated by Degradation Mechanism, and Prospects

ABSTRACT With the rapid development of the electric vehicle industry, the retirement scale of lithium iron phosphate (LiFePO 4 ) batteries has continued to expand, and their efficient and green recycling has become a key issue in resource circulation. This review summarizes the degradation mechanism and regeneration strategies of LiFePO 4 batteries, emphasizing two technical approaches: “Decomposition for regeneration”(Decom‐) and “Repair for regeneration”(Repair). In the decomposition route, valuable metals are recycled and reused through destructive pretreatment combined with pyrometallurgical and hydrometallurgical processes. Conversely, the repair route is based on degradation mechanisms, employing in situ regeneration at the battery or component level, as well as solid‐state sintering, hydrothermal, electrochemical relithiation methods, and modification strategies at the cathode material level. The objective is to recover performance while maintaining the integrity of the complete battery cells or the cathode material structure. This review integrates mechanism analysis with technical comparisons to identify several challenges related to the regeneration technology of spent LiFePO 4 batteries. It anticipates future trends in regeneration technology as well as provides theoretical insights along with practical guidance for the resource recovery and high‐value utilization of retired batteries.