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Triggering the anionic redox reactions at high voltage is an effective approach to boost the capacity of Li-rich layered oxides. However, the irreversible lattice oxygen release at high voltage and sluggish ion kinetics remain conundrums. Herein, a surface modifying coupling defect engineering strategy is proposed to improve the reversibility of anionic redox reactions and ion diffusion efficiency in Li-rich layered oxides. A LiNbO3 surface modification acts as an effective physical barrier to suppresses lattice oxygen release, thereby improving cycling stability of Li-rich layered oxide. Further, the oxygen vacancies in the LiNbO3 coating enhances the ion transport kinetics, strengthening rate capability. After 500 cycles, a high capacity retention of 83.3% can be achieved for the obtained cathode materials (CV-LLO) at 5 C, much higher than that of the pristine materials (LLO, 52.3%). Moreover, CV-LLO delivers a capacity of 169.9 mAh g-1 at 5 C, which was 65.1% of the capacity at 0.2 C, much higher than that of the pristine LLO (85.6 mAh g-1, 33.7%). This study provides insights into the construction of Li-rich layered oxide cathode with highly reversible anionic redox reaction and highly cycling stability for Lithium storage.
Liu et al. (Thu,) studied this question.