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.