Enhancing Structural/Interfacial Stability and Li+ Diffusion Kinetics of LiCoO2 at High Voltage via a Synergetic Strategy

Although elevating the upper cutoff voltage can directly increase the reversible capacity of LiCoO₂ (LCO), severe capacity fading caused by structural and interfacial degradation restricts its practical application. Herein, we propose a synergetic modification strategy combined with La³⁺ doping and LiTaO₃ (LTO) coating to enhance the electrochemical performance of LCO operating at high voltages. Generally, La³⁺ doping can increase the interlayer spacing and significantly increases the ion conductivity, while the LTO coating acts as a robust protection layer, which also facilitates the interfacial Li⁺ diffusion. As a result, comodified LCO shows an enhanced capacity retention of 88.6% after 200 cycles at 3.0–4.5 V, while the capacity retention of Bare LCO is only 25.4%. For a higher cutoff voltage of 4.6 V, comodified LCO still exhibits an excellent capacity retention of 85.7% after 100 cycles.