Can Aluminum Impurity from Current Collectors Upgrade Spent Li1‐xCoO2 into a High‐Performing Cathode for Lithium‐Ion Batteries?

Abstract The recycling of spent lithium‐ion batteries (LIBs) is gaining considerable attention for its potential to address resource scarcity and mitigating environmental pollution. Therefore, the recycling process of spent LIBs should be simple and efficient and minimize the input of raw materials. This work uses residual Al impurities from current collectors combined with high‐temperature Li supplementation to directly repair spent Li1‐xCoO2 cathode into regenerated materials enhanced with Al doping and LiF coating without additional synthesis steps or cost. The regenerated materials demonstrate an enhanced electrochemical performance compared to commercial cathode material. The modified materials exhibit a notable initial discharge capacity of 181 mA h g−1, with a commendable capacity retention of 80.4% after 400 cycles at a 4.5 V cut‐off voltage. The improved electrochemical performance is attributed to the enhanced crystalline and structural stability of the regenerated materials. Furthermore, the superiority of spent materials over commercial materials modification is clarified for the first time through characterizations and theoretical calculations due to their degraded crystalline structure and abundant Li vacancies. This up‐cycling strategy not only contributes to sustainable waste management of spent LIBs but also provides a potential “shortcut” for advancing next‐generation high‐performance batteries.