A Li-rich layered oxide cathode with remarkable capacity and prolonged cycle life

Introducing a facile ion-exchange method coupled with low-temperature thermal treatment, we have developed a strategy to enhance the cycling performance of Lithium-rich manganese-based layered oxides (LLOs). This approach results in the formation of a thin spinel phase layer, which is covered by a fast-ion-conducting Li3PO4 phase on the surface of pristine 0.5Li2MnO3 & sdot;0.5LiMn1/3Co1/3Ni1/3O2 secondary particles of aggregated original nanoparticles, and an increase in oxygen vacancies. After undergoing 200 cycles at a rate of 1 C, the resulting cathode exhibits a high capacity of 204.7 mAh/g with a retention rate of up to 94.4 %, which is significantly superior to that of the original materials. The long-term cycling stability of the modified cathode is also evident at higher rates such as 2, 5, and 8 C. The electrochemical analysis suggests that the surface modification and oxygen vacancies can enhance the Li+ diffusion coefficient, improve anion redox reversibility and increase the capacity contribution from spinel oxidation, thereby improving the electrochemical performance of the cathode during cycling.