Hydrothermal-based direct regeneration of spent Li-ion battery (LIB) cathodes has garnered tremendous attention for its simplicity and scalability. However, it is heavily reliant on manual disassembly to ensure the high purity of degraded cathode powders, and the quality of regenerated materials. In reality, degraded cathodes often contain residual components of the battery, such as binders, current collectors, and graphite particles. Thorough investigation is thus required to understand the effects of these impurities on hydrothermal-based direct regeneration. In this study, we focus on isolating the effects of aluminum (Al) scraps on the direct regeneration process. We found that Al metal can be dissolved during the hydrothermal relithiation process. Even when the cathode material contains up to 15 wt.% Al scraps, no detrimental effects were observed on the recovered structure, chemical composition, and electrochemical performance of the regenerated cathode material. The regenerated NCM cathode can achieve a capacity of 163.68 mAh/g at 0.1 C and exhibited a high-capacity retention of 85.58 % after cycling for 200 cycles at 0.5 C. Therefore, the hydrothermal-based regeneration method is effective in revitalizing degraded cathode materials, even in the presence of notable Al impurity content, showing great potential for industrial applications.
Keywords: Al scraps; Direct regeneration; Hydrothermal relithiation; NCM cathode; Spent Li-ion batteries.
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