Proton conducting plastic crystal electrolytes based on pivalic acid

New materials based on the plastic crystalline phase of pivalic acid were prepared, and their conductivities measured, in order to assess their potential for application as membranes for fuel cells. Pivalic acid has a very low conductivity of approximately 10−13 S cm−1 in the neat form. The objective of this study was to attempt to increase the ionic conductivity of pivalic acid through the addition of bases of varying strengths. Of the bases studied, the heterocyclic molecule, imidazole is the most effective, and upon the addition of 5 mol%, a soft, transparent material with a conductivity of 3.9 × 10−5 S cm−1 at 293 K was obtained. Differential scanning calorimetry was used to study the phase equilibrium in the pivalic acid–imidazole system. The presence of a plastic crystal phase over a temperature range of 21 K was observed in the pivalic acid-rich region.