Advancing Upcycling and Regeneration of Spent LiFePO ₄ : Failure Mechanisms and Recovery Strategies

ABSTRACT With the widespread application of lithium iron phosphate (LFP) batteries in electric vehicles and energy storage fields, the number of retired LFP has increased sharply. Therefore, the development of efficient and environmentally friendly regeneration methods is crucial for the sustainable utilization of resources and environmental protection. In this review, failure mechanism of LFP through advanced characterization technologies is summarized, and upcycling strategies based on the failure mechanism are highlighted. Then, the advantages and challenges of traditional hydrometallurgy, direct regeneration, and upcycling in the recovery of spent LFP (S‐LFP) are explored. Among them, upcycling mainly includes strategies such as structural optimization, phase transformation, and conversion into other functional materials. Moreover, the application of materials obtained by upcycling exhibits broaden aspect, including reusing lithium‐ion batteries, sodium‐ion batteries, and catalytic materials, which significantly improves the economic value of S‐LFP cathode materials. Finally, the upcycling method by combining advanced characterization technologies and machine learning to promote the applications and establish a unified economic and environmental analysis system to provide clear analysis standards for relevant research is emphasized.