Direct regeneration of spent cathode materials by deep eutectic solvent

Current recycling strategies for spent cathode materials mostly rely on destructive reconstruction methods to recover valuable metals; thus, sustainable improvements are urgently required to achieve the low-carbon and short-range recycling of spent lithium-ion batteries. Herein, we report a deep eutectic solvent consisting of ethylene glycol lithium, betaine, and urea (BEU) for the direct regeneration of spent LiCoO2 materials under 80 °C and normal pressure conditions. From an initial capacity of 208.87 mAh/g, the regenerated material achieved a capacity retention rate of 87.10% after 200 cycles. The BEU method achieves direct regeneration of spent LiCoO2 materials through restoring the lack of original composition and defects in the lattice structure. As such, it provides a new platform for the use of a variety of spent lithium cathode resources.