Studies on electrical and dielectric properties of PVP:KBrO4 complexed polymer electrolyte films

Potassium ion conducting polymer electrolytes based on polyvinyl pyrrolidone (PVP) complexed with different weight percent ratios of KBrO4 salt were prepared by using solution cast technique. X-ray diffraction (XRD) and Fourier transform infrared (FT-IR) spectroscopy studies confirmed the complexation of the salt with the polymer. The glass transition temperature and relative percentage of crystallinity of these films were determined using differential scanning calorimetry (DSC). Dielectric measurements were made using ac impedance analyser in the frequency and temperature ranges 1 Hz–1 MHz and 303–373 K respectively. It was observed that the ionic conductivity increased with the increase of salt concentration as well as temperature. The temperature dependence of electrical conductivity of polymer electrolyte films followed Arrhenius relation. The variation of ac conductivity with frequency obeys Jonscher power law. The loss peak observed at 334 K in the dielectric loss spectra was identified as β relaxation. The modulus spectra indicated the non-Debye nature of the material.

► The ionic conductivity increases with the increase in the salt concentration as well as temperature.
► The decrease in dielectric permittivity with frequency is attributed to polar nature of the material, and the loss tangent exhibits a β relaxation peak.
► The modulus spectra indicate the non-Debye nature of the material.