Feasible route for the regeneration of cathode materials from spent lithium-ion batteries via reduction leaching and in-site precipitation

Abstract

With the goal of carbon neutrality, increasing end-of-life spent lithium-ion batteries (LIBs) is inevitable owing to the rapidly growing number of electric vehicles worldwide, which brings management and environmental problems. Nevertheless, the scarcity of valuable metals used in LIBs and the potential value of recycling them have attracted increased interest in recovering spent LIBs. The traditional methods for recycling spent LIBs, pyrometallurgy, and hydrometallurgy cause energy waste and environmental problems. Herein, green reagents, ascorbic acid, is introduced to reduce the amount of strong acid and help in-site precipitate the ternary precursor in this novel process for the recovery of spent LiNi0.5Co0.2Mn0.3O2 (NCM523). A reduction reaction caused by ascorbic acid occurs on the surface of the material, determining the chemical reaction that controls the leaching process and enhances leaching efficiency. The ternary precursor is formed in-site by oxidative precipitation in the leaching solution, which exists ascorbic acid. The regenerated NCM523 shows a high discharge capacity (158.5 mAh g−1 at 0.1C), and the capacity retention rate is 83.7% after 100 cycles. This ascorbic acid coordinated leaching in the sulfuric acid system following in-site precipitation is an environmentally friendly treatment for spent LIBs, which has the potential to be applied in the industry.