We synthesized tris(2,2,2-trifluoroethyl) phosphate (TFP) as a flame-retarding solvent, measured its properties, and studied its effects on the physicochemical properties of the electrolytes LiPF 6 in ethylene carbonate-propylene carbonate-ethyl methyl carbonate (EC-PC-EMC) of 3:3:4 weight ratios. These properties included dielectric constant of the solvent, flammability and conductivity of the electrolytes, and viscosity of the solvent and the electrolytes. The viscosity was studied indirectly through measuring glass transition (T g ) and boiling temperatures of the solvents and electrolytes. We found that TFP reduced the flammability and vapor pressure of the carbonate-based electrolytes, but lowered their conductivity by raising their viscosities and by lowering the dielectric constant of their solvents. Furthermore, this fall of conductivity with TFP content was almost linear, the rate of fall being higher at lower temperatures and higher LiPF 6 concentrations. We compared the conductivity of this system with that of LiPF 6 in EMC-EC, and found a number of important similarities and differences. We also calculated vanishing mobility temperature T 0 from fitting the Vogel-Tamman-Fulcher equation to the conductivity/temperature data and found it changed the same way as T g did: it rose with TFP content and LiPF 6 concentration.

中文翻译：

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磷酸三（2,2,2-三氟乙基）酯作为阻燃助溶剂对 3:3:4 重量比的 EC-PC-EMC 中 LiPF[sub 6] 电解质物理化学性质的影响

我们合成了磷酸三(2,2,2-三氟乙基)酯 (TFP) 作为阻燃溶剂，测量了其性质，并研究了其对碳酸亚乙酯-碳酸亚丙酯-碳酸甲乙酯中的 LiPF 6 电解质理化性质的影响(EC-PC-EMC) 的重量比为 3:3:4。这些特性包括溶剂的介电常数、电解质的可燃性和电导率，以及溶剂和电解质的粘度。通过测量溶剂和电解质的玻璃化转变温度 (T g ) 和沸点温度来间接研究粘度。我们发现 TFP 降低了碳酸盐基电解质的易燃性和蒸气压，但通过提高其粘度和降低其溶剂的介电常数来降低其电导率。此外，这种电导率随 TFP 含量的下降几乎是线性的，在较低温度和较高 LiPF 6 浓度下下降率更高。我们将该系统的电导率与 EMC-EC 中 LiPF 6 的电导率进行了比较，并发现了许多重要的异同。我们还通过将 Vogel-Tamman-Fulcher 方程拟合到电导率/温度数据计算了消失迁移温度 T 0 ，发现它的变化方式与 T g 相同：它随着 TFP 含量和 LiPF 6 浓度而上升。