Abstract: To address the rapidly growing demand for energy storage and power sources, large quantities of lithium-ion batteries (LIBs) have been manufactured, leading to severe shortages of lithium and cobalt resources. Retired lithium-ion batteries are rich in metal, which easily causes environmental hazards and resource scarcity problems. The appropriate disposal of retired LIBs is a pressing issue. Echelon utilization and electrode material recycling are considered the two key solutions to addressing these challenges. Consequently, both approaches have become integral to the life cycle of LIBs, encompassing production and use. The pressure to protect the ecological environment and the scarcity of metal resources have necessitated the importance of echelon utilization and material recycling of retired LIBs. These practices have emerged as important contributors to the sustainable development of the battery industry. This paper provides a comprehensive review of the echelon utilization and material recycling of retired batteries. First, the reasons for the performance degradation of LIBs during use are comprehensively analyzed, and the necessity of recycling retired batteries is analyzed from the perspectives of ecology and safety, sustainable development, economy, energy conservation and emission reduction. Second, the key technologies, problems and challenges faced by the current echelon utilization are summarized, as are typical application examples at home and abroad. Third, the recycling technology of waste LIB materials is systematically summarized, including traditional recycling technology and new green recycling technology, as well as direct recycling technology for waste LIB materials. Finally, the potential for echelon utilization and the recycling of waste battery materials are explored, and several conclusions are drawn.

Key words: Carbon neutrality, Echelon utilization, Green recycling, Direct regeneration, Spent lithium-ion batteries