X射线光电子能谱
电解质
电化学
介电谱
阴极
材料科学
扫描电子显微镜
化学
化学工程
分析化学(期刊)
电极
物理化学
复合材料
色谱法
工程类
作者
Long Wang,Yulin Ma,Li Q,Yingzhi Cui,Panpan Wang,Xinqun Cheng,Pengjian Zuo,Yunzhi Gao,Geping Yin
标识
DOI:10.1016/j.electacta.2017.05.008
摘要
Tris(2,2,2-trifluoroethyl) phosphite (TTFEP) is investigated as an electrolyte additive to improve the electrochemical performance of LiNi1/3Co1/3Mn1/3O2 cathode at high operating voltage (4.6 V). Charge/discharge measurements demonstrate that TTFEP is effective to improve the cycling stability and rate capability of LiNi1/3Co1/3Mn1/3O2 cathode. The capacity retention of LiNi1/3Co1/3Mn1/3O2/Li cell with 1% TTFEP-containing electrolyte reaches up to 85.4% after 100 cycles at 0.5C (1C = 160 mA g−1), while that of the cell with the baseline electrolyte (1 M LiPF6 in EC/DMC electrolyte) only remains 74.2%. Moreover, the discharge capacity of the cathode with 1% TTFEP-containing electrolyte could maintain around 112.0 mAh g−1 at 4C. Based on the characterization of electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), a protective interphase film formed on the cathode surface can be found due to the preferential oxidation of TTFEP, which inhibits the electrolyte decomposition and mitigates the cathode structural destruction, leading to the improved electrochemical performance of LiNi1/3Co1/3Mn1/3O2 cathode at high voltage.
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