Title: Multi-strategy synergistic Li-rich layered oxides with fluorine-doping and surface coating of oxygen vacancy bearing CeO2 to achieve excellent cycling stability

Authors: Jie Mei, Yuanzhi Chen, Wanjie Xu, Wei He, Laisen Wang, Qingshui Xie, Dong-Liang Peng*

Abstract: Li-rich layered oxides (LLOs) have attracted extensive attentions because of their high reversible capacity and operating voltages for advanced lithium-ion batteries. However, the practical applications of LLOs are restricted by the rapid decay of capacity and voltage. Herein, multi-strategy synergistic Li_1.2Mn_0.54Ni_0.13Co_0.13O₂cathode materials with flourine-doping and surface coating of oxygen vacancy bearing CeO₂ are prepared through a processing involving co-precipitation and subsequent calcination. The obtained cathode materials exhibit micron-sized olive-shaped particles that are comprised by nanoscale primary particles. Electrochemical testing results indicate that the multi-strategy synergistic LLO exhibits discharge specific capacities of 287.4 mAh g⁻¹ at 0.2 C and 211.3 mAh g⁻¹ at 2 C. Compared to the pristine LLO without modifications, high capacity retentions of 76.3% after 500 cycles at 2 C, and 79.1% after 600 cycles at 5 C have been observed for the modified LLO, which are almost 2.0 and 2.5 times that of the pristine LLO. Besides, a voltage drop of 0.511 V after 500 cycles at 2 C, and a voltage drop of 0.514 V after 600 cycles at 5 C are also observed, indicating inhibited voltage attenuation. This work demonstrates that multi-strategy synergy by flourine-doping and surface coating of oxygen vacancy bearing CeO₂ can effectively enhance the cycling stability and restrain voltage attenuation of LLO cathode materials.

Full-Link: https://www.sciencedirect.com/science/article/pii/S1385894721053730