Interface stabilization of 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether to high-voltage Li-rich Mn-based layered cathode materials

• 作者: A-Lin Li Guo-Hua Li Shi-Gang Lu Zhi-Min Ren Jian-Tao Wang Hao-Xiang Zhuo Wei Quan Gang-Ning Zhang Fu-Juan Han Yi-Mian Xia Jing Wang Yi Zhang
• 来源期刊: 稀有金属（英文版）
• 年，卷（期）: 2022,（3）
• 所属期刊栏目: LETTERS
• 页码范围: 822-829
• 页数: 8页
• 语种: 英文

摘要

Non-aqueous electrolyte solvents play a pivotal role in improving the cycling performance of high-voltage Li-rich Mn-based layered cathode materials.In this study,a fluo-roether(1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether,TFEPE)was added to 1.2 mol·L-1 LiPF6 EC/EMC/DEC at different concentrations to synthesize a series of electrolytes for enhancing the cycling performance of high-voltage Li1.18Mn0.50Ni0.26Co0.06O2(LMNC).Effects of TFEPE on the electrochemical performance of LMNC at 0.1C and 1.0C rates were investigated.Scanning electron microscopy was used to observe the surface morphology of LMNC before and after cycling.X-ray photoelectron spectroscopy was conducted to analyze the surface com-positions and chemical states,and transmission electron microscopy was performed to directly examine the changes in the structure of LMNC before and after cycling.Results suggested that TFEPE was preferentially oxidized and produced inorganic compounds(MeF and Li2CO3)on the surface of LMNC,which effectively inhibited the side reactions between LMNC and the electrolyte.MeF and Li2CO3 delayed the propagation of the phase transitions of LMNC primary particles from the surface to the bulk,thereby improving the cycling performance of LMNC.