Characterization of poly(vinyl alcohol)/potassium chloride polymer electrolytes for electrochemical cell applications

A solid polymer electrolyte system based on poly(vinyl alcohol) (PVA) complexed with potassium chloride (KCl) salt was prepared by using solution cast technique. The complexation of KCl salt with the polymer was confirmed by X-ray diffractrometer and Fourier transform infrared spectroscopy. Differential scanning calorimetry was used to determine the melting temperatures and crystallinity of the pure PVA and complexed films. Ionic conductivities of the electrolytes have been determined by AC impedance studies in the temperature range 303–373 K. The conductivity was found to increase with the increase in dopant concentration and temperature. Transference number data suggests that the charge transport in this polymer electrolyte system is mainly due to ions. Optical absorption studies were made in the wavelength range 200–800 nm on pure and KCl doped PVA films. The absorption edge, direct band, and indirect band gap values were evaluated. It was found that the energy gaps and band edge values shifted to lower energies on doping. Electrochemical cells were fabricated with the configuration of K/(PVA þ KCl)/(I2 þ C þ electrolyte) and discharge characteristics were studied under a constant load of 100 kO. Various cell parameters, such as open circuit voltage, short circuit current, power density, and energy density were determined. POLYM. ENG. SCI., 52:1685–1692, 2012. a 2012 Society of Plastics Engineers