Construction of Stable Oxygen Redox by Electrochemical Activation O–TM–Se in Nickel‐Rich Layered Oxides for Lithium‐Ion Batteries

The irreversible oxygen redox and structural degradation of LiNi 0.8 Co 0.1 Mn O 2 (NCM811) at a 4.5 V high voltage cause severe decline in cycling performance for lithium‐ion batteries. In this study, novel approach is proposed to enhance the anionic chemistry stability NCM811 cathode material by introducing gaseous selenium. Se β+ species are selectively adsorbed within vacancies, leading continuous replacement α− form stable O–TM–Se bond during deep charging. Furthermore, Selenium modification improves cationic efficiency alleviates (α < 2) outward migration, increases vacancy formation energy. activity diminished, facilitating improved reversibility effectively inhibiting escape. Additionally, energy barrier phase transition, suppressing transition Ni migration. reacts with escaping SeO , reducing side reactions cycling. As result, significantly inhibits release, remarkable cyclic 87.5% capacity retention after 300 cycles 1C maintained 192.9 mAh g −1 150 under 60C. realizes strategy design high‐energy‐density materials superior performance.