Study of effect of composition, irradiation and quenching on ionic conductivity in (PEG)_x: NH₄NO₃ solid polymer electrolyte

Abstract

We have prepared, characterized and investigated a new PEG-2000 based solid polymer electrolyte (PEG)_x : NH₄NO₃. Ionic conductivity measurements have been made as a function of salt concentration as well as temperature in the range 265-330 K. Selected compositions of the electrolyte are exposed to a beam of 8 MeV electrons and ⁶⁰Co γ-rays to an accumulated dose of 10 kGy to study the effect on ionic conductivity. The electrolyte samples are also quenched at liquid nitrogen temperature and conductivity measurements are carried out. The ionic conductivity at room temperature exhibits a characteristic peak for the composition, x = 46. Electron beam irradiation results in an increase in conductivity for all compositions by a factor of 2-3. Exposure to γ-rays enhances the conductivity by one order of magnitude. Quenching at low temperature has resulted in an increase in conductivity by 1-2 orders of magnitude. The enhancement of conductivity upon irradiation and quenching is interpreted as due to an increase in amorphous region and decrease in crystallinity of the electrolyte. DSC and NMR measurements also support this conclusion.