Abstract:

As countries around the world are vigorously developing the new energy vehicle industry，the number of power batteries，mainly of lithium-ion batteries（LIBs），has increased rapidly.However，LIBs have limited lifespan，and the early installed LIBs have met their retired requirements in recent years.There is an urgent need for effective recycling of the large number of decommissioned batteries，which would otherwise cause issues to the environment and human beings，as well as lead to the loss of precious metal resources.Traditional battery recycling technologies，mainly of pyrometallurgy or hydrometallurgy，can realize the fine recovery and reuse of various components of retired LIBs，but are usually polluting，energy intensive and long recovery cycle.Therefore，it is urgent to develop green，energy-saving and efficient LIBs recycling technology.In recent years，the emerging direct regeneration technology has attracted much attention due to its advantages of simple process，low carbon emission，low energy consumption and short recycling cycle.The several current mainstream direct regeneration technologies for cathode materials and their advantages and disadvantages were reviewed，their contributions in term of low cost and low energy consumption were analyzed and the functionalization of cathode materials and the latest development of LIBs closed-loop recycling was introduced.Finally，the prospects and development trends of the recycling of retired LIBs cathode materials and other components were forecasted，aiming to provide a reference for the field of battery recycling.

Key words: lithium-ion battery, cathode material, direct regeneration, functionalization, closed-loop recycling