Ion transport mechanism in proton-conducting gel-type electrolytes: solvent and polymer effects

The development and characterization of proton-conducting gel-type electrolytes containing simple aliphatic dicarboxylic acids gelled with poly(vinylidenefluoride-co-hexafluoropropylene) (PVdF-HFP) has been investigated in the present work. The relation between the various properties and the composition of the electrolyte constituents with different electrical/physical properties has been investigated and established. Electrical properties for the developed gel-type electrolytes were found to depend upon the acidity and concentration of acid and the amount of polymer present. This dependence is explained due to the combined effect of change in ion concentration, viscosity, and physical interactions taking place between the constituents of electrolytes. Maximum conductivity of 1.59 × 10⁻³ S/cm is observed at room temperature for electrolytes containing 1 M oxalic acid. The interactions and behavior of the electrolytes are supported by Fourier transform infrared, nuclear magnetic resonance, viscosity, and pH studies.