ABSTRACT Direct regeneration of spent layered ternary oxide cathodes offers a sustainable pathway for resource recovery and circular battery manufacturing. However, their long‐term stability is fundamentally constrained by intrinsic electronic interactions. In particular, the inherent π‐type hybridization between Ni 3 d orbitals and O 2 p orbitals facilitates detrimental Ni migration and rock‐salt phase formation, ultimately leading to rapid capacity degradation. Here, we leverage the preexisting Li vacancies in spent LiNi 0.5 Co 0.2 Mn 0.3 O 2 (NCM) as orientation sites to induce localized lattice stress fields during regeneration. The resulting lattice perturbation modulates the spin configuration of bridging O anions, thereby triggering antiferromagnetic coupling between adjacent Ni cations and O anions. Consequently, the Ni─O orbital hybridization transitions from weak π‐dominated to robust σ‐dominated interactions, as evidenced by enhanced covalent character of the Ni─O bonds. This reinforced bonding framework effectively suppresses Ni migration and defect propagation during repeated lithiation/delithiation cycles. As a result, the regenerated NCM cathode exhibits significantly improved durability, retaining ∼60% of its initial capacity after 750 cycles. These findings reveal a direct correlation between the local valence bond evolution and cycling reversibility of cathode materials, offering new design principles and mechanistic insights for stabilizing regenerated cathode materials.
Li et al. (Wed,) studied this question.