50 MeV Li3+ ion irradiation effect on structural, electrical, and dielectric properties of PVA-based nanocomposite polymer electrolytes

Nanocomposite polymer electrolyte thin films of polyvinyl alcohol (PVA)-orthophosphoric acid (H3PO4)-Al2O3 have been prepared by solution cast technique. Films are irradiated with 50 MeV Li3+ ions having four different fluences viz. 5 x 10(10), 1 x 10(11), 5 x 10(11), and 1 x 10(12) ions/cm(2). The effect of irradiation on polymeric samples has been studied and characterized. X-ray diffraction spectra reveal that percent degree of crystallinity of samples decrease with ion fluences. Glass transition and melting temperatures have been also decreased as observed in differential scanning calorimetry. A possible complexation/interaction has been shown by Fourier transform infrared spectroscopy. Temperature-dependent ionic conductivity shows an Arrhenius behavior before and after glass transition temperature. It is observed that ionic conductivity increases with ion fluences and after a critical fluence, it starts to decrease. Maximum ionic conductivity of similar to 2.3 x 10(-5) S/cm owing to minimum activation energy of similar to 0.012 eV has been observed for irradiated electrolyte sample at fluence of 5 x 10(11) ions/cm(2). The dielectric constant and dielectric loss also increase with ion fluences while they decrease with frequency. Transference number of ions shows that the samples are of purely ionic in nature before and after ion irradiation.