Toward High Voltage Performance of LiCoO2 Cathode Materials Directly Regenerated with a Bulk and Surface Synergistic Approach from Spent Lithium-Ion Batteries

The improvement in electrochemical performance of regenerated LiCoO2 materials at a high cutoff voltage is beneficial for efficient and high value recycling of spent lithium-ion batteries. Herein, a novel approach was developed for direct regeneration of spent LiCoO2 materials with the synchronous modification to inhibiting the interface side reaction at high cutoff voltage. The initial discharge capacity of synergistic regenerated LiCoO2 material displays 174.29 mAh g–1 with the capacity retention rate of 96.77% after 200 cycles under conditions of 3.0–4.5 V. The discharge capacity of the synergistic regenerated LiCoO2 material reaches 158.478 mAh g–1 at 5C with a retention capacity of 98.16% after returning to 0.1C. The cladding layer composed of Al2O3 and LiCo1–yAlyOz solid solution on the surface of synergistic regenerated materials is beneficial to suppress the side reactions and prevent corrosion or attack and came from harmful substances during the cycle process. Our finding of the synergistic regeneration approach provides a new idea for efficient and high value direct regeneration of other spent cathode materials.