Direct Regeneration of Spent LiNi0.5Co0.2Mn0.3O2 Cathodes by Utilizing Eutectic Lithium Salts for High-Performance Lithium-Ion Batteries

With the wide application of lithium-ion batteries (LIBs), many spent LIBs will face the problem of recycling and treatment in the future. The recycling of valuable substances from battery materials is particularly important. In this paper, the spent LiNi0.5Co0.2Mn0.3O2 (S-NCM523) cathode material from used LIBs was regenerated by using the eutectic lithium salt of Li2CO3/LiOH. The lithium element lost by S-NCM523 was supplemented through solid–liquid contact with the molten lithium salt, restoring the layered structure at high temperatures. The successful repair of the regenerated material was verified by various characterization methods, including the elimination of the rock salt phase and the lower Li+/Ni2+ disorder. This research shows that the regenerated cathode material still has a high specific discharge capacity of 146.8 mAh/g after 100 cycles, with a capacity retention rate of 96.0%. The excellent electrochemical performance of the regenerated material demonstrates the feasibility of directly regenerating spent NCM using the molten salt method.