Efficient and Selective Dissolution of Li from Lithium-Ion Battery LiFePO₄ Cathode by Natural Deep Eutectic Solvents

Abstract

Due to the wide application of lithium iron phosphate (LFP)-based lithium-ion batteries (LIBs), the dissolution of LFP is a crucial step in the process of recycling LFP from LFP-based LIBs. However, the traditional methods for the dissolution of LFP typically require the usage of hazardous solvents, elevated temperatures, or limited efficiency. Achieving efficient, green, and selective dissolution of LFP at low temperatures remains a significant challenge. Here, we, for the first time, find that natural deep eutectic solvents (NADESs) containing glucose and lactic acid show a high Li leaching efficiency of 96.5% for LFP dissolution at a mild temperature, with Li more selectively separated from LFP than Fe. Both glucose and lactic acid in DESs are naturally available, cheap, biodegradable, and nontoxic. This research provides valuable guidance for the development of a green, mild, natural, and efficient process for achieving a sustainable recovery of spent LFP-based LIBs.