Sustainable high-efficiency photocatalytic lithium recovery from spent LiFePO4 batteries: green process design and performance validation

Abstract

Recycling spent lithium iron phosphate batteries is of great significance for both economic and environmental protection. Herein, a new strategy has been introduced: using MoS₂, a green and recyclable photocatalyst, to efficiently extract Li from spent lithium iron phosphate batteries. The dissolution conditions for valuable metals were optimized by varying the ratio of MoS₂ to spent lithium iron phosphate (sLFP), the ratio of water to MoS₂, leaching time, temperature, and other parameters. The results indicated that under the optimized conditions, the leaching rate of Li exceeded 98%, while the leaching rates of Fe and P were below 20%, and the leaching P and Fe could be converted to FePO₄ by air oxidation. Using Na₂CO₃ as a precipitant, more than 99% of Li could be recovered from the leaching solution in the form of Li₂CO₃. Besides, the results of repeated leaching and light irradiation experiments indicated that the photocatalyst MoS₂ had excellent reusability. Furthermore, photocatalytic reactions under high Li⁺ concentration conditions demonstrated the feasibility of Li⁺ enrichment processes.