中国物理B ›› 2015, Vol. 24 ›› Issue (7): 78201-078201.doi: 10.1088/1674-1056/24/7/078201
• INTERDISCIPLINARY PHYSICS AND RELATED AREAS OF SCIENCE AND TECHNOLOGY • 上一篇 下一篇
张舒a, 李文俊a, 凌仕刚a, 李泓a, 周志彬b, 陈立泉a
Zhang Shu (张舒)a, Li Wen-Jun (李文俊)a, Ling Shi-Gang (凌仕刚)a, Li Hong (李泓)a, Zhou Zhi-Bin (周志彬)b, Chen Li-Quan (陈立泉)a
摘要: The cycling performance, impedance variation, and cathode surface evolution of the Li/LiCoO2 cell using LiFSI–KFSI molten salt electrolyte are reported. It is found that this battery shows poor cycling performance, with capacity retention of only about 67% after 20 cycles. It is essential to understand the origin of the instability. It is noticed that the polarization voltage and the impedance of the cell both increase slowly upon cycling. The structure and the properties of the pristine and the cycled LiCoO2 cathodes are investigated by x-ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectroscopy, x-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). It is found that the LiCoO2 particles are corroded by this molten salt electrolyte, and the decomposition by-product covers the surface of the LiCoO2 cathode after 20 cycles. Therefore, the surface side reaction explains the instability of the molten salt electrolyte with LiCoO2.
中图分类号: (Lithium-ion batteries)