Preparation and Dielectric Investigation of Sulfonated PEEK Films for Fuel Cell Application

Abstract: Wide frequency range dielectric properties of proton conducting films of sulfonated polyetheretherketone have been investigated in the range of 0.1 Hz-1 MHz from 10 to 220°C. In all cases, the AC conductivity obeys to the universal Jonsher's law at higher frequencies. At high temperatures, the critical exponent decreases by increasing temperature compatibly with CBH conducting model. The DC conductivity is well fitted to the Arrhenius law with decreased activation energy by increasing the sulfonation degree. By the use of the electric modulus approach, we showed the presence of two different relaxation modes thermally activated.