Surface Vacancy Engineering Re‐Routes First‐Cycle Redox for Stabilized Li‐Rich Layered Cathodes

Abstract We demonstrate that atomic‐scale surface disorder can control the first‐cycle redox sequence of Li‐rich layered oxides, eliminating the detrimental process of oxygen release and lattice collapse that degrades performance. In Li 1.14 Ni 0.32 Mn 0.54 O 2 (LNMO), a simple chemical treatment introduces oxygen and transition metal (TM) vacancies confined to the particle surface while preserving the bulk layered framework. Multi‐modal synchrotron analyses reveal that these vacancies trigger an early oxygen oxidation below 4.4 V, delay nickel oxidation to higher potential, and suppress the formation of covalent Ni 4+ ─O states. This modified pathway prevents irreversible oxygen release, suppresses manganese dissolution, and maintains metal‐oxygen coordination at high voltages. Consequently, the treated cathode delivers higher first‐cycle Coulombic efficiency (CE), mitigated voltage fade, and superior capacity retention. By directly linking engineered surface disorder to redox reactions and associated structural transformations, this work establishes a general design principle for durable, high‐energy‐density cathodes.