Facilitating Cathode Regeneration via Defect‐Driven Prelithiation

Abstract Direct regeneration of electrode materials has been in the spotlight due to its potential resource recovery and environmental benefits, especially for LiNi x Co y Mn z O 2 (NCM) cathode materials. Yet, prior studies have predominantly emphasized innovating regeneration methods, overlooking the intrinsic defects of spent NCM and their effects in the regeneration process. This study proposes a mechanism aimed at facilitating lithiation regeneration by modulating the surface defects of spent NCM. The generation of oxygen defects in degraded NCM intensifies the adsorption of lithium source, effectively reducing the energy barrier for Li + migration from surface to bulk. Simultaneously, mechanical energy is employed to alter the local thermodynamic state to provide a driving force for lithium migration, allowing it to undergo a prelithiation reaction before roasting. The temperature range in which the phase transition occurs during the roasting process becomes more concentrated. This contributes to increasing opportunities for lithium insertion and accelerates the repair of crystal structure, resulting in favorable properties of regenerated materials. This strategy innovatively exploits the inherent defects of spent NCM, proposes the critical role of synergistically regulating defect kinetic and thermodynamic features in facilitating regeneration, providing a unique perspective for the design of direct NCM regeneration technology.