Nondestructive Hydrothermal Recycling for Layered Materials in Lithium-Ion Batteries via Lithium–Proton Exchange

With the increasing production of lithium-ion batteries (LIBs) driven by the growth of electric vehicles, efficient recycling is essential for a sustainable future. Current recycling methods, such as hydrometallurgy and pyrometallurgy, have limitations including complex processes and high energy consumption. To overcome these issues, in this study, we propose a novel method for recycling layered positive electrode materials via a Li+–H+ exchange reaction. In this method, the layered materials of LiCoO2 (LCO), LiNi1/3Co1/3Mn1/3O2 (NCM), and LiNi0.88Co0.09Al0.03O2 (NCA) undergo a reaction in an oxidizing aqueous solution, resulting in the leaching of lithium ions and the formation of transition-metal oxyhydroxides as precipitates. Furthermore, we successfully resynthesize the original materials from the oxyhydroxides with recovery rates of 95% for LCO, 80% for NCM, and 30% for NCA. This result suggests that the presence of potassium ions from the oxidant affects the electrochemical performance, especially for Ni-rich materials such as NCA. Our results not only suggest a new way to recycle Li-ion batteries with a simpler and more efficient process but also provide a framework for future research to improve the recovery rate.