Effect of plasticizer on ionic transport and dielectric properties of PVA–H3PO4 proton conducting polymeric electrolytes

Solid polymer electrolytes have attracted considerable attention due to their wide variety of electrochemical device applications. The present paper is focused on the effect of plasticizer to study the structural, electrical and dielectric properties of PVA–H3PO4 complex polymer electrolytes. XRD results show that the crystallinity decreases due to addition of plasticizer up to particular amount of polyethylene glycol (PEG) and thereafter it increases. Consequently, there is an enhancement in the amorphicity of the samples responsible for process of ion transport. This characteristic behavior can be verified by the analysis of the differential scanning calorimetry results. FTIR spectroscopy has been used to characterize the structure of polymer and confirms the complexation of plasticizer with host polymeric matrix. Electrical and dielectric properties have been studied for different wt% of plasticizer and their variations have been observed. The addition of PEG has significantly improved the ionic conductivity. The optimum ionic conductivity value of the plasticized polymer electrolyte film of 30 wt% PEG has been achieved to be of the order of 10−4 S cm−1 at room temperature and corresponding ionic transference number is 0.98. The minimum activation energy is found to be 0.25 eV for optimum conductivity condition.