Electrochemical Relithiation in Spent LiFePO<sub>4</sub> Slurry for Regeneration of Lithium-Ion Battery Cathode

Recycling\nspent lithium-ion batteries (LIBs) in a green and economical\nway is vital for maintaining the sustainability of the LIB industry.\nHowever, given the low content of high-value components in olivine-type\nlithium iron phosphate (LFP), traditional metallurgical processes\nare economically unfeasible for recycling due to high chemical/energy\nconsumption and labor-intensive procedures. This study proposes a\nfacile electrochemistry strategy to directly regenerate the spent\nLFP material by an electrically driven lithiation process as a spent\nLFP slurry (200 g/L) rather than as electrodes. Minimal energy and\nchemical consumption are achieved by enabling the healing of spent\nLFP without destroying the original olivine-type crystal structure.\nThe proposed method utilizes mild healing conditions (25 °C for\n2 h) and LiCl solution as the only reagent in the regeneration process,\nsignificantly lowering the expenses associated with producing cathode\nelectrodes. The electrochemical performance of the regenerated LFP\nhave been dramatically recovered after regeneration, exhibiting a\ncapacity of 151.5 mA h g<sup>–1</sup> at 0.1 C and 96.6% capacity\nretention over 400 cycles at 1 C. This approach demonstrates a high\nprocessing capability and offers considerable economic and environmental\nbenefits, making it an eco-friendly option and supporting the sustainable\ndevelopment of the LFP industry.