(711b) Leveraging Reversible Chemistry for Green and Efficient Battery Recycling

Sustainable manufacturing of lithium-ion batteries (LIBs) is critical for future energy storage. Layered oxides (e.g., LiNi_xCo_yMn_zO₂, 0<x,y,z<1, x+y+z=1) or NCM is becoming the dominating cathode material in high energy LIBs, which have degradation issues after limited cycling life due to the formation of defects with Li loss and phase changes. Directly resolving these defects to generate new cathodes can not only reduce the high cost but also prevent environmental pollution from disposal of used LIBs. However, currently there is no effective approach to tackle this challenge. We report an effective strategy to resolve the defects of degraded cathode particles to directly regenerate NCM which can achieve very high electrochemical performance. Specifically, we developed a non-destructive approach to successfully renovate degraded LiNi_1/3Co_1/3Mn_1/3O₂ (NCM111) and LiNi_0.5Co_0.2Mn_0.3O₂ (NCM523) particles. The regenerated NCM particles well maintained their original particle morphology and size distribution. Our method can successfully resolve both the compositional and structural defects of NCM particles. Due to the reconstruction of ideal stoichiometry, low cation mixing and high phase purity, NCM particles regenerated by our approach show high specific capacity, long cycling stability and high rate capability, reaching high performance of pristine cathode materials. This work demonstrates a novel energy-efficient approach to resolve the defects of degraded cathode particles to remanufacture high-performance cathodes, with distinct advantages over traditional hydrometallurgical methods. In addition, our approach can be also extended to resolve the defects of other types of cathode materials after long-time cycling. Therefore, this study builds an important foundation for sustainable manufacturing of energy materials.