Resolving the Compositional and Structural Defects of Degraded LiNi_<i>x</i>Co_<i>y</i>Mn_<i>z</i>O₂ Particles to Directly Regenerate High-Performance Lithium-Ion Battery Cathodes

Abstract

Layered oxide LiNixCoyMnzO2 (0 < x,y,z < 1, x + y + z = 1) or NCM is becoming the dominating cathode material in high-energy lithium-ion batteries (LIBs), which have degradation issues after cycling due to Li loss and phase changes. Directly resolving these issues to generate new cathodes cannot 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. Here we demonstrate a nondestructive process to directly regenerate degraded NCM cathode particles to obtain new active particles. Using this method, nearly ideal stoichiometry, low cation mixing, and high phase purity were achieved in the regenerated NCM particles, which offer high specific capacity, good cycling stability, and high rate capability, all reaching pristine materials. Our work represents a simple yet efficient approach to directly regenerate high-performance NCM cathodes with distinct advantages over traditional hydrometallurgical methods and builds an important foundation for the sustainable manufacturing of energy materials.