¹H solid state NMR studies on the proton conducting polymer electrolytes

Solid polymer electrolytes based on polyvinyl alcohol (PVA)/ammonium acetate have been prepared for different compositions by solution cast technique. The polymer electrolytes have been characterized by X-ray diffraction (XRD), DSC, conductivity studies and ¹H solid state NMR. The XRD study reveals the amorphous nature of the polymer electrolyte. The maximum protonic conductivity at room temperature has been found to be 5.62 × 10^{- 6} S cm^{- 1} for 12.5 mol% salt doped electrolyte and the electrolyte obeys Arrhenius behaviour. ¹H NMR study has been employed to develop a better understanding of the conduction mechanism. Variable temperature NMR has indicated that proton line width shows an exponential decrease with the increase of temperature. The NMR studies indicate that the NH₄⁺ ion is responsible for the proton conduction and the anionic motion is also involved in the conduction process at higher temperature.