A Cascading Closed-Loop Strategy for Recycling and Production of Ternary Cathode Material from Spent Lithium-Ion Batteries in an Entirely Acidic Environment

The closed-loop recovery of valuable metals from spent lithium-ion battery (LIB) cathodes and their regeneration into high-performance cathodes are crucial for resource efficiency. However, conventional closed-loop processes use acids for leaching and strong alkalis for coprecipitation, which prevents true integration. Here, a cascading closed-loop strategy is proposed to leach metal ions from the spent LiNi0.5Co0.2Mn0.3O2 (NCM523) ternary material using organic acid and then produce NCM523 ternary material in the acidic leachate through a cation chelation and reassembly process. The entire process is carried out in an open vessel under ambient conditions within 40 min. The closed-loop process-derived NCM523 (CLP-NCM523) has the target stoichiometry and a one-dimensional quasi-single crystal structure, which enhances Li+ diffusion kinetics. The leaching efficiencies for Ni, Co, and Mn are 98.37%, 98.39%, and 99.43%, respectively, and the recovery efficiencies are 83.71%, 86.29%, and 81.61%, respectively. CLP-NCM523 cathodes exhibit superior electrochemical performance, particularly at high rates: 101.4 mA h g–1 at 10C (vs 69.5 mA h g–1 for commercial NCM523) and 86.7% capacity retention after 200 cycles. This strategy reduces the costs of converting acidic leachate to alkaline solution and avoids uneven element distribution in the precursor that occurs in coprecipitation-based closed-loop processes, demonstrating high potential for sustainable LIB recycling.