Effect of nano TiO2 filler on the structural and electrical properties of PVP based polymer electrolyte films

A composite polymer electrolyte system based on PVP:KIO4 with dispersed nano TiO2 filler in different concentrations was prepared by solution casting. Structural investigations were carried out using X-ray diffraction, Fourier transform infrared (FT-IR) spectroscopy and scanning electron microscopy (SEM). Electrical conductivity measurements were performed by a computer controlled phase sensitive multimeter (PSM 1700) in the frequency and temperature range 1 Hz-1 MHz and 303-373 K, respectively. It was observed that the magnitude of conductivity increased with increase in the nano TiO2 filler concentration as well as with temperature. The addition of nano TiO2 filler to the PVP:KIO4 electrolyte system was found to result in enhancement of the ionic conductivity. The maximum ionic conductivity 0.665 × 10−3 S/cm was obtained for 10 wt% nano TiO2 filler in the composite at room temperature. The conducting species of charge transport in these nano composite polymer electrolyte films were examined by the Watanabe technique and it was found that the charge transport is predominantly due to cations. Using these polymer electrolytes (KIO4 complexed and TiO2 nano composite), electrochemical cells were fabricated with the configuration of K/(Polymer film)/(I2 + C + electrolyte), and discharge characteristics were studied under a constant load of 100 kΩ. Various cell parameters, such as open circuit voltage, short circuit current, power density and energy density were determined.