Proton-conducting polymer electrolyte based on PVA-PAN blend doped with ammonium thiocyanate

Abstract

Blending of polymers is one of the most useful methods for modulating the conductivity of solid polymer electrolytes. Blend polymer electrolytes have been prepared with polyvinyl alcohol (PVA)-polyacrylonitrile (PAN) blend doped with ammonium thiocyanate with different concentrations by solution casting technique, using dimethyl formamide (DMF) as the solvent. The prepared electrolytes are characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), nuclear magnetic resonance (NMR), ultraviolet (UV), and ac impedance measurement techniques. The increase in amorphous nature of the blend polymer electrolyte by the addition of salt is confirmed by XRD analysis. The complex formation between the polymers and the salt has been confirmed by FTIR analysis. The thermal behavior has been examined using DSC and TGA. The maximum conductivity has been found to be 2.4 × 10−3 S cm−1 for 92.5PVA/7.5PAN/25 % NH4SCN sample at room temperature. The temperature dependence of conductivity has been studied with the help of Arrhenius plot, and the activation energies are calculated. The proton conductivity is confirmed by dc polarization measurement technique. 1H NMR studies reveal the presence of protons in the sample. A proton battery is constructed with the highest conducting sample, and its open circuit voltage is measured to be 1.2 V