Reconstruction of lithium replenishment channel with an amorphous structure for efficient regeneration of spent LiCoO ₂ cathodes

Lithium-ion batteries (LIBs) with LiCoO2 (LCO) as cathodes are widely used in the various electronic devices, indicating the importance for the recycling of spent LCO. However, due to the existence of cobalt oxide with spinel phase on the surface of highly-degraded LCO, the strong electrostatic repulsion from a transition metal octahedron leads to a high lithium replenishment barrier, which poses a great challenge when regenerating the highly-degraded LCO. Herein, a structural transformation strategy is proposed to reconstruct lithium replenishment channel for direct regeneration of highly-degraded LCO. This approach uses continuous ball milling to disrupt the inherent structure of highly-degraded LCO, thereby releasing the internal stress and converting the surface spinel phase into the homogeneous amorphous structure, which is more favorable to the lithium inserting and regenerating. The regenerated LCO delivers an outstanding discharge capacity of 179.1 mAh g^-1 in the voltage range of 3.0-4.5 V at 0.5 C. This strategy offers a unique regeneration approach for highly-degraded LCO, facilitating the development of the regeneration industry for spent LIBs cathode materials.