In this work, we used tris(2,2,2-trifluoroethyl) phosphite (TTFP), in which the oxidization number of phosphorus was three (III), to formulate nonflammable electrolytes of the Li-ion batteries. Using 1 m (mole solute per kilogram solvent) LiPF₆ 3:3:4 (w) propylene carbonate (PC)/ethylene carbonate (EC)/ethyl methyl carbonate (EMC) electrolyte as a baseline, the effect of TTFP on the flammability and conductivity of the electrolytes, as well as the cell performance was evaluated. It is observed that the addition of TTFP can substantially reduce flammability of the electrolytes at a small expense in the ionic conductivity. When the TTFP content reaches 15 wt.% versus the solvent, the electrolyte becomes nonflammable. In Li/graphite half-cell, TTFP not only suppresses PC decomposition and graphite exfoliation but also increases Coulombic efficiency (CE) of the lithiation and delithiation cycle. In Li/cathode (a lithium nickel-based mixed oxide cathode) half-cell, TTFP has negligible adverse impact on the cycling performance when the cells are cycled between 2.7 and 4.2 V. In graphite/cathode Li-ion cell using PC-based electrolytes, TTFP can improve cycling performance, especially at high temperature (60 °C), since its presence favors the formation of solid electrolyte interface (SEI) film on the graphite electrode and increases thermal stability of LiPF₆-based electrolytes.

中文翻译：

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亚磷酸三（2,2,2-三氟乙基）酯作为锂离子电池不可燃电解质的助溶剂

在这项工作中，我们使用了磷的氧化数为三（III）的亚磷酸三（2,2,2-三氟乙基）酯（TTFP）来配制锂离子电池的不可燃电解质。使用1 m（每千克溶剂摩尔溶质）LiPF ₆3：3：4（w）作为基准的碳酸亚丙酯（PC）/碳酸亚乙酯（EC）/碳酸乙基甲基酯（EMC）电解质，TTFP对电解质的可燃性和电导率以及电池性能的影响被评估。观察到，添加TTFP可以以很少的离子传导性成本来实质上降低电解质的可燃性。当TTFP含量相对于溶剂达到15重量％时，电解质变得不可燃。在锂/石墨半电池中，TTFP不仅抑制PC分解和石墨剥落，而且还提高了锂化和脱锂循环的库仑效率（CE）。在锂/锂（锂镍基混合氧化物阴极）半电池中，当电池在2.7至4.2 V之间循环时，TTFP对循环性能的影响可忽略不计。₆基电解质。