Investigation of the Preferential Selective Recovery of Lithium from Cathode Materials of Spent Lithium−Ion Batteries Via Carbothermic Reduction

Abstract

The recovery of lithium resources from spent lithium−ion battery cathode materials mitigates the present scarcity of lithium resources and establishes favorable circumstances for the sustainable development of the lithium−ion battery industry. The retrieval of valuable metals from cathode materials through reduction roasting has been extensively researched; however, the selective extraction of Li still requires further advancement. Hence, in this study, spent ternary lithium−ion battery cathode materials are utilized as raw materials, and graphite serves as a reducing agent to accomplish the selective extraction of Li via the carbothermal reduction and acid−free leaching coupling approach. Under the optimum conditions, the total recovery rate of lithium exceeds 99.8%, and the purity surpasses 99.9%. Subsequently, by employing the HSC9 equilibrium calculation, the mechanism governing the gas phase composition and Li−containing phases during the reduction process of the cathode material is clarified, preventing the volatilization loss of Li from the roasting process at the source. This technology is intended to offer a reference for achieving the goal of selective recovery of Li from cathode materials.

Keywords: spent lithium−ion battery, Cathode material, Lithium, Selective recovery