Reconstruction of lithium replenishment channel with an amorphous structure for efficient regeneration of spent LiCoO₂ cathodes

Lithium-ion batteries with LiCoO₂ (LCO) cathodes are widely used in various electronic devices, resulting in a large amount of spent LCO (SLCO). Therefore, there is an urgent need for an efficient technique for recycling SLCO. However, due to the presence of cobalt oxide with a spinel phase on the surface of highly-degraded LCO, the strong electrostatic repulsion from the transition metal octahedron poses a high Li replenishment barrier, making the regeneration of highly-degraded LCO a challenge. Herein, we propose a structural transformation strategy for reconstructing Li replenishment channels to aid the direct regeneration of highly-degraded LCO. In this approach, ball milling is employed to disrupt the inherent structure of highly-degraded LCO, thereby releasing the internal stress and converting the surface spinel phase into a homogeneous amorphous structure, which promotes Li insertion and regeneration. The regenerated LCO (RLCO) exhibits an outstanding discharge capacity of 179.10 mAh·g⁻¹ in the voltage range of 3.0–4.5 V at 0.5 C. The proposed strategy is an effective regeneration approach for highly-degraded LCO, thereby facilitating the efficient recycling of spent lithium-ion battery cathode materials.