Multicationic Modulation Combining With Epitaxial Entropy‐Tailored Coating Unlocking 4.65 V Operation of Chemomechanically Stable LiCoO ₂ Cathode

ABSTRACT

To meet the escalating demand for high‐performance LiCoO ₂ (LCO) cathodes, elevating the charging cut‐off voltage becomes highly imperative to achieve markedly enhanced specific capacities. However, high‐voltage operation is always accompanied by structural instability, notably deleterious bulk phase transitions and severe interfacial degradation. Herein, we propose a collaborative strategy that integrates a medium‐entropy (Mg, Eu, and W) doped bulk architecture with an in situ formed epitaxial entropy‐assisted MoB surface coating, which effectively suppresses the detrimental surface‐initiated structural degradation, enabling a robust, high‐voltage‐tolerant LCO cathode. The synergistic co‐doping of Mg, Eu, and W not only strengthens the structural framework without crack formation but also curtails lattice oxygen loss while accelerating Li ⁺ diffusion kinetics. Moreover, the in situ generation of an entropy‐stabilized MoB coating provides exceptional resistance against corrosion induced by electrolyte decomposition. Using this design principle, the LCO featuring surface‐to‐bulk synergistic modification is endowed with exceptional wide‐temperature‐tolerant electrochemical stability at a high voltage of 4.65 V, delivering an outstanding rate capability of 153.3 mAh g ⁻¹ at 5C and long‐term cycling stability with 84.4% capacity retention after 400 cycles. Our contribution hugely advances the high‐voltage LCO cathodes toward the practical commercialization of high‐energy‐density lithium‐ion batteries.