Measurement and Correlation of the Electrical Conductivity of the Ionic Liquid [BMIM][TFSI] in Binary Organic Solvents

Abstract

In this paper, the electrical conductivities of ionic liquid 1-butyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide ([BMIM][TFSI]) in mixed organic solvents of propylene carbonate (PC) + γ-butyrolactone (GBL) and ethylene carbonate (EC) + dimethyl carbonate (DMC) were measured. The effects of mixed organic solvents with different ratios (1:0, 2:1, 1:1, 1:2, 0:1) on the electrical conductivity of ionic liquid were investigated. The organic solvents EC and DMC have a synergistic effect for the electrical conductivity of [BMIM][TFSI]–EC/DMC, and the optimal ratio of EC to DMC is 1:1; however, the organic solvents have no synergistic effect in [BMIM][TFSI]–PC/GBL. The concentration dependence of the electrical conductivity of the solution can be well fitted by the empirical Casteel–Amis equation. The effects of temperature on electrical conductivity can be described by the Vogel–Tamman–Fulcher (VTF) equation and the Arrhenius equation. The IL concentration dependence of the activation energy Ea and t...