Enhanced ionic conductivity in oxygen ion irradiated poly(vinylidene fluoride-hexafluoropropylene) based nanocomposite gel polymer electrolytes

In the present work, effect of Swift Heavy Ion (SHI) irradiation by 90 MeV O7+ ion with four different fluences on P(VdF − HFP)–(PC + DEC)–LiClO4-dedoped (insulating) polyaniline (PAni) nanofibers polymer electrolytes have been investigated. The irradiated films have been investigated by ac impedance, XRD, FTIR, DSC and SEM analyses. It has been observed that irradiation with swift heavy ion shows increase in ionic conductivity of the composite gel polymer electrolyte films at lower fluences (≤1011 ions/cm2) and decrease at higher fluences (≥1011 ions/cm2) as compared to the unirradiated film. Maximum ionic conductivity of 1.2 × 10− 2 S/cm at room temperature has been found after irradiation with fluence 1011 ions/cm2. The increase in ionic conductivity at lower fluences could be attributed to the scissioning of polymer bonds, which leads to larger segmental motion of polymer backbone resulting in faster ionic transport through the polymer matrix. However at higher fluences (≥1011 ions/cm2) the polyaniline nanofibers get phase separated out from P(VdF − HFP)–(PC + DEC)–LiClO4 leading to decrease in ionic conductivity. The phase separation phenomenon has been confirmed by DSC, FTIR and dielectric loss spectra. The surface morphology of the irradiated films has been examined by SEM.