Direct Recycling of Cathode Materials from Spent Lithium-Ion Batteries: Principles, Strategies, and Perspectives

In recent years, lithium-ion batteries have become an important part of the global transition to green and low-carbon energy. However, due to the rapidly increasing demand and production of lithium-ion batteries, there is a large amount of spent batteries that need to be disposed of. The most critical and valuable recycling of spent batteries is the recycling of cathode materials. Pyrometallurgy and hydrometallurgy are traditional recycling processes aimed at extracting valuable metal elements from cathode materials. However, these methods have several disadvantages, including destruction of the structure of cathode materials, lengthy repair processes, high energy consumption and high environmental pollution. The direct recycling process is a popular repair technology for cathode materials in lithium-ion batteries. The aim is to restore or upgrade the cathode materials in a non-destructive manner or convert them into other functional products for secondary use, characterized by a short repair process, high atom utilization, lower costs and lower carbon emissions. This perspective summarizes the current status of lithium-ion battery recycling, with a focus on direct recycling of cathode materials. It describes the pretreatment process, theoretical foundations, direct regeneration strategies and perspectives and provides insights for relevant researchers.