Resolving the Structural Defects of Spent Li1−xCoO2 Particles to Directly Reconstruct High Voltage Performance Cathode for Lithium‐Ion Batteries

Effective and scalable recycling of spent lithium-ion batteries is an urgent need to address the environmental pollution and resource consumption caused by improper disposal. Herein, a practical solution is presented to recover and increase the stability of the layered structure from scrap Li1-x CoO2 via high-temperature supplementation of Li and Mg doping, without an extra synthesis step or cost. All the regenerated products exhibit better electrochemical performance compared with the commercial cathode material. Within the voltage window of 3.0-4.6 V, 5% Mg-recovery LiCoO2 (LMCO) exhibits a high discharge capacity of 202.9 mA h g-1 at 0.2 C, and 3% Mg-recovery LiCoO2 shows enhanced capacity retention of 99.5% at 0.2 C after 50 cycles and maintains 96.8% at 1 C after 100 cycles. This is because high-temperature supplementing metal ions is beneficial for eliminating the cracks and nano-impurity particles on the surface of spent materials, thereby restoring the layered structure and electrochemical performance. The excellent electrochemical performances of Mg-recovery LiCoO2 are attributed to Mg ions doping, which can inhibit the release of lattice oxygen and stabilize the surface structure. This process maximizes the utilization of the spent materials and provides a novel perspective for the non-constructive recovery of spent materials.