Analysis of Direct Recycling Methods for Retired Lithium-ion Batteries from Electric Vehicles

The rapid expansion of electric vehicle (EV) fleet calls for large number of lithium-ion batteries to be recycled at their end-of-life. Various recycling methods have been developed or under development to recover the high-value materials from retired lithium-ion batteries. Amongst these methods, direct recycling techniques have been developed and reported to recycle battery materials for reuse in new battery manufacturing since the electrochemical properties of the recycled materials can be fully recovered to the same level of pristine materials. In literature, innovative sintering processes have been developed to recover the composition and crystal structure of spent cathode materials; hydrothermal regeneration processes have been reported to regenerate the spent cathode materials in the solvents at a moderate temperature, followed by the high-temperature short annealing process. The regenerated cathode materials show the same specific capacity and cycling performance as those of pristine materials. The electrochemical regeneration method is applied to fully recover the electrochemical performance of cathode material with stable crystal structure. While the direct recycling techniques are still under development, their future applications in industry are still not clear. This study aims to classify and summarize state-of-the-art of the direct recycling methods, and evaluate the regenerated cathode materials’ performance and the application potential to be used for manufacturing of new lithium-ion batteries in future. The results will help increase understanding of the direct recycling technologies and facilitate the associated R&D for future industrial scaling-up of direct recycling processes for retired lithium ion batteries from electric vehicles.