Homogeneous Repair of Highly Degraded Ni‐Rich Cathode Material with Spent Lithium Anode

Direct regeneration of spent lithium-ion batteries has received wide attention owing to its potential for resource reuse and environmental benefits. The repair effect of direct regeneration methods undergoing heterogeneous repair process is usually inferior, while homogenous repair process plays a vital role to achieve satisfactory repair results. However, the practical applications of current homogeneous repair methods are challenged by the complex operations and relatively high costs owing to the requirement of additional heating or pressurization. Herein, this work proposes a simple strategy to achieve homogeneous repair of spent cathode materials under relatively mild conditions by uniformly precoating lithium source at room temperature and atmospheric pressure. Followed by annealing, highly degraded LiNi_0.83Co_0.12Mn_0.05O₂ with severe Li deficiency and irreversible phase transition is repaired to have an initial capacity of 181.6 mAh g^-1 and capacity retention of 80.7% after 150 cycles at 0.5 C. The lithium source used in this strategy is from the spent lithium anode. Moreover, this strategy is suitable for the direct regeneration of various layer oxide cathode materials with different failure degrees. This work provides both theoretical guidance and practical examples for the straightforward, effective, and universally applicable direct regeneration methods.