Uniform Repair of Spent NCM through a Hydrogen-Bonded Organic Framework-Assisted Process

Abstract

Direct regeneration of spent layered cathode materials is a promising recycling strategy, but it is still limited by non-uniform lithium distribution during relithiation. Herein, a hydrogen-bonded organic framework (HOF)-mediated regeneration strategy is proposed to achieve uniform lithium replenishment and structural reconstruction of degraded LiNi0.5Co0.2Mn0.3O2 (NCM523) cathodes. Density functional theory calculations and time-of-flight secondary ion mass spectrometry results demonstrate that HOF promotes the homogeneous distribution of lithium ions, enhances lithium-ion adsorption, and facilitates subsequent bulk diffusion during sintering. As a result, the regenerated cathode exhibits reduced Li/Ni cation mixing, restored layered structure, better Li+ transfer kinetics, and improved electrochemical performance approaching that of commercial NCM523. Moreover, life cycle assessment and techno-economic analysis demonstrate the environmental and economic advantages of the proposed strategy. This work provides an effective approach for the sustainable regeneration of spent layer-structured cathode materials.