Recycling Spent LFP Batteries: From Resource Recovery to High-Value Functional Materials.

With the growing wave of end-of-life new energy vehicles, the recycling of lithium iron phosphate (LFP) batteries has become increasingly imperative. In contrast to conventional pyrometallurgical and hydrometallurgical approaches, recent efforts have shifted toward innovative recycling strategies and emerging applications for spent LFP materials. During battery operation, the irreversible oxidation of Fe to Fe often leads to lithium loss and performance degradation. To address this, various approaches-such as electrochemical delamination and ultrasonic separation-have been developed to efficiently detach cathode materials from current collectors, followed by thermal or wet-chemical regeneration to restore their electrochemical activity. Beyond conventional regeneration, the upcycling of spent LFP into value-added functional materials offers a sustainable pathway for resource reutilization. Notably, phosphorus extracted from LFP can be converted into slow-release fertilizers, broadening the scope of secondary applications. As the volume of spent LFP batteries continues to rise, there is an urgent need to establish an integrated recycling framework that harmonizes environmental impact, technical efficiency, and economic viability. Henceforth, this review summarizes recent advances in LFP recycling and upcycling, discusses critical challenges, and provides strategic insights for the sustainable and high-value reuse of spent LFP cathodes.