Structural and dielectric properties of NaIO4 - Complexed PEO/PVP blended solid polymer electrolytes

Poly (ethylene oxide) (PEO)/Polyvinyl pyrrolidone (PVP) blended solid polymer electrolytes complexed with NaIO4 salt at different weight percentage ratios were prepared using solution casting technique. Effect of salt complexation on structural properties of pure blend (PEO/PVP) electrolyte was investigated by X-ray diffraction (XRD), Raman spectroscopy and Scanning electron microscopic (SEM) studies. Modifications in glass transition temperature and thermal stability of the blend electrolytes were measured by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) studies. The determined refractive index values from optical absorption spectra were found to increase with the increase of salt concentration. Impedance measurements were made in the frequency range of 0.1 Hz-1 MHz to explore dielectric response and ion dynamics of the blend electrolytes as a function of NaIO4 salt concentration. The PEO/PVP blend complexed with 10 wt% of NaIO4 salt was demonstrated higher room temperature conductivity of 1.56 × 10−7 S/cm. The temperature dependence of DC conductivity of blend electrolytes was followed the Arrhenius behaviour. Determined diffusion coefficients (DNa+) using Trukhan model and estimated mobility (μ) values of sodium ions were increased with increase of salt concentration. To get the further insights into the ion dynamics, the complex dielectric permittivity has been modeled with Havriliak-Negami function.