1H-1,2,4-Triazole as solvent for imidazolium methanesulfonate

Abstract

The solvation effect of 1H-1,2,4-triazole towards imidazolium methanesulfonate was studied by blending imidazolium methanesulfonate and 1H-1,2,4-triazole. Upon addition of 1H-1,2,4-triazole, the melting point of imidazolium methanesulfonate was lowered to less than 100 °C while maintaining the high ionic conductivity for a wide composition range of the blend. The ionic conductivity of the blend can be adequately described by using the Vogel–Fulcher–Tamman equation. A vehicle mechanism is postulated to govern the proton conduction for the blend. The contribution of protons to the ionic conductivity was corroborated electrochemically. The blend exhibited electrochemical activities for H₂ oxidation and O₂ reduction at a Pt electrode, as well as a wide electrochemical window. Therefore, suitable blends can possibly serve as electrolytes for polymer electrolyte membrane fuel cells operating under non-humidifying conditions. The solvation effect studied herein suggests a promising approach to a wider application area of protic ionic liquids.