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

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 H(2) oxidation and O(2) 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.