Atomic Layer‐Deposited LSO Coating Stabilizes the Interface and Enhances the Electrochemical Performance of High‐Nickel NCM811 Cathode Material

LiNi _0.8 Co _0.1 Mn _0.1 O ₂ (NCM811) cathode material has attracted considerable attention because of its potential to achieve substantially higher energy densities, but the practical deployment of NCM811 remains hindered by severe interfacial and structural degradation during repeated cycling. Atomic layer deposition (ALD) was employed in this study to construct an amorphous Li─Si─O (LSO) coating layer with different thicknesses on the surface of NCM811 cathode materials, and their effects on the structural characteristics, interfacial properties, and electrochemical performance were systematically investigated. Among all the samples, 50 LSO@NCM811 exhibits the best electrochemical performance, retaining a discharge capacity of 115.96 mAh g ⁻¹ after 500 cycles at 1 C under a cutoff voltage of 4.3 V. By constructing a stable and ionically conductive interfacial protective layer, the LSO coating achieves the synergistic optimization of interfacial stability, structural stability, and electrochemical kinetics, thereby markedly enhancing the electrochemical performance of NCM811 cathode materials. This work provides important insights into interfacial engineering design for high‐nickel layered cathode materials of lithium‐ion batteries.