Sustainable and efficient strategies for recovering spent LiFePO₄-based lithium-ion batteries

Lithium iron phosphate (LiFePO₄)-based lithium-ion batteries (LIBs), the mainstream LIBs, have a certain lifespan due to capacity loss and abnormal damage. Spent LiFePO₄-based LIBs will eventually pose a significant threat to resources, the environment, and humans. Recovering spent LiFePO₄-based LIBs becomes a hotspot field with the increasing environmental, economic, and social benefits. However, the conventional technologies have not yet been widely and maturely industrialized. Sustainable, efficient, and low-cost methods and relevant mechanisms are still within investigation. In this review, the failure mechanisms of LiFePO₄-based LIBs including the defect mechanism of LiFePO₄ were clarified. After conventional pretreatments according to industrial scale, black powders were obtained, and a series of methods were comprehensively described to treat black powders. The pyrometallurgy is potential as an auxiliary means to activate spent materials for subsequent hydrometallurgy. The direct regeneration is promising to obtain high value-added cathode materials if impurities are removed before. The hydrometallurgy is adept at addressing the separation and recycling metals. Hydrometallurgical processes are sustainable, efficient, and cost-effective to meet industrial demands for recovering spent LiFePO₄-based LIBs.