ABSTRACT Owing to its economic and environmental benefits, direct regeneration has been regarded as a promising approach. However, for degraded high‐nickel layered cathodes during cycling, the rock‐salt phase could be formed on the surface, serving as Li‐ions diffusion barrier, which would inhibit the in‐depth relithiation and structural recovery. Herein, the Li 2 MoO 4 ‐induced surface reconstruction strategy is proposed to successfully regenerate spent NCM. Significantly, the surface properties are further reconstructed, along with the doping of Mo‐atoms into the lattice framework with improved stability. Assisted by ex/in situ exploring, it could be confirmed that Li 2 MoO 4 could promote charge redistribution and strengthen TM─O─Mo coupling, which contributes to the lowering of Li + migration barrier and the recovery of layered phase. As a result, the as‐regenerated NCM delivers a high discharge capacity of 179.1 mAh g − 1 at 1.0 C and retains 87.71% capacity after 200 cycles, better than that of traditional solid‐state regenerated NCM (58.11%). Moreover, the reconstructed surface is beneficial for suppressing structural strain and interfacial side reactions, leading to improved kinetic behavior and stability. This work is expected to shed light on the transformation behaviors for overcoming surface structural barriers, meanwhile offering significant strategies for direct regeneration of high‐nickel cathodes.
Zhou et al. (Wed,) studied this question.