Characterization of C2H2O4 doped PVA solid polymer electrolyte

Abstract A novel solid polymer electrolyte based on poly vinyl alcohol (PVA) with oxalic acid was prepared by the solution caste technique. X-ray diffraction (XRD) and differential scanning calorimetry (DSC) measurements carried out on the samples clearly revealed the modification of the PVA structure; the PVA crystallinity was reduced with increasing oxalic acid content and became more amorphous. The surface morphology of these complexed polymer electrolytes was analyzed by scanning electron microscopy (SEM). Fourier transform infrared spectroscopy (FTIR) spectral studies of the samples suggested that the interaction between H + ions of oxalic acid and oxygen of the hydroxyl group (OH) of PVA plays a major role in proton conductivity. The optical absorption studies were performed on these samples in a range of wave numbers from 200 nm to 600 nm and the optical band gap values were evaluated. Direct current (DC) conductivity was measured and temperature dependence in the range 27–273°C was studied. It was observed that the conductivity at temperatures beyond the glass transition temperature (T g ) showed a Vogel-Tamman-Fulcher (VTF) type behavior. The electrical conductivity studies on PVA with oxalic acid, in a 70:30 proportion by wt%, demonstrated that the polymer composite is a promising electrolyte for applications in electrochemical cells.