Sustainable and Facile Method for the Selective Recovery of Lithium from Cathode Scrap of Spent LiFePO4 Batteries

Lithium recovery from spent LiFePO4 batteries is significant to prevent resource depletion and environmental pollution. In this study, the employment of "water in salt" electrolyte in LiFePO4 battery enlightened us to develop a novel method for the selective recovery of lithium from spent LiFePO4 batteries through oxidizing LiFePO4 to FePO4 with sodium persulfate (Na2S2O8). Effect of several variables on the Li leaching efficiency was investigated. Additionally, combined thermodynamic analysis and characterization of XRD, XPS were employed to investigate the leaching mechanism. More than 99% of Li can be selectively leached in 20 min at ambient temperature with only 0.05 times excess of Na2S2O8. The high leaching efficiency can be ascribed to the stability and without destruction for the solid structure during the oxidation leaching. A closed-loop process was then proposed for recycling entire spent LiFePO4 batteries, and finally high purity Li2CO3 (99 wt %) was successfully prepared. The process is economically feasible and environmentally friendly and has great potential for the industrial-scale recycling of spent LiFePO4 batteries.