Although high‐voltage positive electrode materials for high energy density lithium‐ion batteries have gained a great attention, the lack of compatible electrolytes with sufficiently high oxidative stability to deliver an excellent cycling ability restricts their practical application. Fluorinated solvents are considered as promising candidates for high‐voltage electrolyte solvents. In this study, we select 1,1,2,2‐tetrafluoroethyl‐2,2,3,3‐tetrafluoropropyl ether (TTE) with a high boiling point, low cost, and good SEI‐filming ability as a co‐solvent of fluoroethylene carbonate‐based electrolytes and extensively investigate its physicochemical and electrochemical properties for applications in high‐voltage lithium‐ion batteries. Our experimental results show that the TTE‐containing electrolyte exhibits not only a high oxidative stability up to 5.5 V (vs. Li/Li⁺), but also excellent wettability with the separator. In addition to high discharge capacity and increased coulombic efficiency of the Li/LiNi_0.5Mn_1.5O₄ half‐cell assembled with the TTE‐containing electrolyte cycled between 3.0 and 4.9 V, the cell also displays a high rate capability. This work shows that partially fluorinated ethers, e. g., TTE, are promising co‐solvents for high‐voltage electrolytes that can enable commercial development of high energy density lithium‐ion batteries.

中文翻译：

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1,1,2,2-四氟乙基-2-2,2,3,3-四氟丙基醚作为高压锂离子电解质的助溶剂的物理化学和电化学性质

尽管用于高能量密度锂离子电池的高压正电极材料备受关注，但缺乏具有足够高氧化稳定性以提供出色循环能力的兼容电解质限制了它们的实际应用。氟化溶剂被认为是高压电解质溶剂的有希望的候选者。在本研究中，我们选择具有高沸点，低成本和良好SEI成膜能力的1,1,2,2-四氟乙基-2,2,3,3-四氟丙基醚（TTE）作为共溶剂。基于碳酸氟亚乙酯的电解质，并对其在高压锂离子电池中的应用进行了广泛的理化和电化学性能研究。我们的实验结果表明，含TTE的电解质不仅具有高达5的高氧化稳定性。与。Li / Li ⁺），但与隔膜的润湿性也极好。除了Li / LiNi _0.5 Mn _1.5 O ₄半电池的高放电容量和库伦效率的提高，其含TTE的电解质在3.0至4.9 V之间循环外，还显示出高倍率性能。这项工作表明，部分氟化的醚，例如。例如，TTE是有前途的高压电解液助溶剂，可实现高能量密度锂离子电池的商业开发。