Improving the cycling and air-storage stability of LiNi 0.8 Co 0.1 Mn 0.1 O 2 through integrated surface/interface/doping engineering

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Materials for energy and sustainability, 2020-03, Vol.8 (10), p.5234-5245
• Main Authors: Zhai, Yanwu, Yang, Wenyun, Ning, De, Yang, Jinbo, Sun, Limei, Schuck, Götz, Schumacher, Gerhard, Liu, Xiangfeng
• Format: Article
• Language: English
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/C9TA13014D

The poor cycling performance and storage instability of Ni-rich layered oxide cathode materials seriously restrict their practical application. Herein, we report to improve the cycling and air-storage stability of LiNi 0.8 Co 0.1 Mn 0.1 O 2 through integrated surface/interface/doping engineering. The capacity retention after 500 cycles at 5C is largely enhanced from 69.6 to 80.6%. After 70 days of storage in air, the initial discharge capacity at 5C is 143.1 mA h g −1 and the capacity retention after 500 cycles is 88.5%. The cycling and air-storage stability can be attributed to the integration of the Li 2 ZrO 3 protective layer, Zr 4+ doping and the rock-salt interface phase from Li 2 ZrO 3 coating. The Li + -conductive Li 2 ZrO 3 layer suppresses the side reaction as well as enhances the Li-ion diffusion at the interface. In the meantime, Zr 4+ doping enlarges the lithium slab thickness and decreases Li/Ni disorder, which further enhances Li-ion diffusion in the bulk. Zr 4+ doping makes TM–O bonds more stable and alleviates the lattice changes during charge–discharge cycles owing to the strong Zr–O bond. Moreover, the formed rock-salt phase on the interface further enhances the stability of the layered structure. More importantly, the Li 2 ZrO 3 coating suppresses the formation of an electrochemically insulating substance on the cathode surface, which dramatically improves the long term air-storage stability.