Research on electrochemical properties of nonaqueous ionic liquid microemulsions

The nonaqueous ionic liquid (IL) microemulsions composed of 1-butyl-3-methylimidazolium tetrafluoroborate, Triton X-100, and toluene were prepared and the electrochemical properties of the nonaqueous IL microemulsions were investigated in this paper. It is shown that characteristics of the nonaqueous IL microemulsions such as electrical conductivity, electrochemical window, and solubility are good, which indicate that the nonaqueous IL microemulsions can be used as electrolyte for electrochemical research. The electrochemical properties of the nonaqueous IL microemulsions were researched by cyclic voltammetry (CV) and electrochemical impedance spectroscopy methods using potassium ferricyanide as electroactive probe. It was found that the reversibility was better and the peak current densities of CV were higher for the [Fe(CN)₆]³⁻/[Fe(CN)₆]⁴⁻ electrode reaction in the nonaqueous IL microemulsions than those in IL. However, the electrochemical behavior of the probe in the nonaqueous IL microemulsions with different microenvironments (oil-in-IL, IL-in-oil, and bicontinuous) was different. The electrochemical property of the probe in the oil-in-IL microemulsion was the best, which was studied in detail.