A. K. Sharma

Structural, Electrical and Optical Characterization of Pure and Doped Poly (Vinyl Alcohol) (PVA) Polymer Electrolyte Films

A sodium ion conducting polymer electrolyte based on Poly (Vinyl Alcohol) (PVA) complexed with Sodium Iodide (NaI) was prepared using solution cast technique. The structural properties of composite PVA polymer electrolyte films were examined by XRD. The XRD results revealed that the amorphous domains of PVA polymer matrix increased in size with the increase of NaI salt concentration. The variation in film morphology was examined by scanning electron microscopy. FT-IR spectra studies for pure PVA and complexed films revealed the vibrational changes that occurred due to the effect of dopant salt in the polymer. DC conductivity was measured in the temperature range of 303–373° K and the conductivity was found to increase with the increase of dopant concentration as well as temperature. Optical absorption studies were made in the wavelength range 200–600 nm. The absorption edge, direct band gap, and indirect band gap values were evaluated.

Electrical Conduction and Dielectric Relaxation Phenomena of PVA Based Polymer Electrolyte Films

Conducting polymer electrolyte (CPE) films based on poly(vinyl alcohol) (PVA) complexed with NaI salt were prepared by a solution cast technique. The structural properties of these electrolyte films were examined by XRD studies. The XRD results revealed that the amorphous domains of PVA polymer matrix were increased with the increase of NaI salt concentration. The glass transition temperature (T g ) of these systems was determined by DSC thermograms. Electrical conductivity was measured in the temperature range of 303-373 K and the conductivity was found to increase with the increase of dopant concentration, as well as temperature. The activation energy values were 0.478, 0.351, 0.319 and 0.284 eV for pure and 10%, 20% and 30% NaI complexed PVA films, respectively. The dielectric constant (ϵ′) was found to increase with the increase of temperature and decrease with the increase of frequency. Dielectric relaxation phenomenon was observed in the dielectric loss spectra and is attributed to the orientation of polar groups.

Investigations on Structural and Electrical Properties of KClO4 Complexed PVP Polymer Electrolyte Films

Potassium ion-conducting polymer electrolytes based on poly (vinyl pyrrolidone) (PVP) complexed with KClO4 were prepared using a solution cast technique. These samples were characterized using X-ray diffraction (XRD), Fourier transform infrared (FT-IR), Differential Scanning Calorimetry (DSC), and impedance spectroscopy. The complexation of the salt with polymer was confirmed by FT-IR and XRD studies. The ionic conductivity was found to increase with increasing temperature and salt concentration. The highest ionic conductivity (0.91 × 10−5 S/cm) and low activation energy (0.29 eV) was obtained for the polymer complexed with 15 wt% KClO4 among all the compositions.

Studies on (PEO+PVA+KIO3) polymer blend electrolyte films for electrochemical cell applications

Abstract Poly(ethylene oxide)–poly(vinyl alcohol) (PEO-PVA) blended polymer electrolytes complexed with KIO3 salt at different weight percentage ratios were prepared using solution casting technique. The complexation of salt with (PEO+PVA) polymer blend was confirmed by X-ray diffraction and Fourier transform infrared spectroscopic studies. The melting temperature of the polymer blend electrolytes was measured from differential scanning calorimetry studies. Impedance measurements were made in the frequency range of 100 Hz–1 MHz and the temperature range of 300–370 K. The electrical conductivity was found to increase with increasing dopant concentration as well as temperature. Transference number measuements were performed to characterise the polyblend electrolyte for battery applications. It is concluded that the present electrolyte is predominantly an ionic conductor. Using these electrolytes, electrochemical cells with the configuration K/(PEO+PVA+KIO3)/(I2+C+electrolyte) were fabricated, and their discharge characteristics are reported. Other cell parameters, including open circuit voltage and short circuit current, were also evaluated and are reported.