Efficient Direct Regeneration of Spent LiCoO2 Cathode Materials by Oxidative Hydrothermal Solution

The traditional direct regeneration of cathode material of spent lithium-ion batteries is encountering the challenge of high energy consumption. Here, an oxidative hydrothermal solution has been developed for direct regeneration of spent LiCoO 2 materials in low-temperature operation. The regenerated cathode material displays a better structural transformation with single-crystal particle morphology. More Co 2+ in spent LiCoO 2 materials are successfully transformed to Co 3+ in regenerated cathode materials. The initial discharge capacity of regenerated cathode materials reaches 153.46 mAh/g with a capacity retention rate of 95.02% after 200 cycles, which are both significantly higher than that of 39.83% in regenerated materials obtained by the traditional hydrothermal regeneration process. This oxidative hydrothermal solution can provide the electrochemical driving force to accelerate the repair of defects of spent cathode materials and break the limit of kinetics under low-temperature conditions. The low-temperature hydrothermal regeneration process is available to guide efficient and economically reasonable recycling of spent cathode materials.