Structural, thermal, electrical, and dielectric properties of synthesized nanocomposite solid polymer electrolytes

In the present article, polyvinyl alcohol (PVA) polymer, sodium iodide (NaI) salt, and fumed silica nanoparticles nanofiller have been used for the preparation of solid polymer electrolyte films. Fourier transform infrared spectroscopy has been performed to study the vibrational change due to the complexation among polymer, salt, and nanofiller. X-Ray diffraction has been carried out to study the structural changes in the PVA:NaI (60:40) polymer electrolyte films with fumed silica nanoparticles as dopant. Differential scanning calorimetry studies show decreasing trend in the glass transition temperature for nanocomposite polymer electrolyte films. Thermogravimetric analysis has been performed to study the thermal degradation of the sample. Determination of transference number using Wagner's polarization technique indicates that the ions are the dominant mobile species. Maximum conductivity of approximately 3.8 x 10(-3) S cm(-1) at room temperature has been estimated for PVA:NaI (60:40) film containing 0.5% fumed silica nanoparticles with low value of activation energy. Dielectric relaxation studies with temperature show shifts of the relaxation time toward higher value for samples of nanocomposite polymer electrolyte films.