Tailored Ta ₂ O ₅ /TiO ₂ Nanointerfaces Engineering for Reinforced Structural Integrity and High‐Voltage Performance of Single‐Crystal Ni‐Rich Cathodes

Single-crystal Ni-rich ternary materials possess great potential as cathode materials for lithium-ion batteries (LIBs) due to their high discharge specific capacity and excellent cycling performance. However, their practical utilization is hindered by irreversible phase transitions during cycling, sluggish Li⁺ diffusion, escape of lattice oxygen, and the interfacial side reactions. To address these obstacles, an engineered advanced single-crystal LiNi_0.8Co_0.1Mn_0.1O₂ (SC-NCM) is reported by adopting a surface modification strategy using Ta₂O₅ and TiO₂ to mitigate surface degradation. Experimental results demonstrate that the dual modification effectively stabilizes lattice oxygen, significantly suppresses Li⁺/Ni²⁺ cation mixing, and improves Li⁺ diffusion kinetics. Under a 2.8-4.3 V voltage for 200 cycles at 1 C, the dual-modified material demonstrates a capacity retention rate of 91.1%, distinctively outperforming the pristine SC-NCM (54.9%). Moreover, even at harsh cycling conditions with a 4.5 V cut-off voltage, the designed material retains 64.2% of its capacity, nearly double that of pristine SC-NCM after 200 cycles. Furthermore, the TaTi-NCM || graphite pouch cell achieves a capacity retention of 90.3%, significantly surpassing the 81.7% retention observed in the pristine SC-NCM counterpart after 1000 cycles. This work guides the design of high-performance single-crystal Ni-rich cathode materials through a synergistic modification strategy.