(PEO)(8)ZnCl2 polymer electrolytes and nanocomposites were prepared using PEO gamma-irradiated by a selected dose of 309 kGy and TiO2 nanograins. The influence of the added nanosize TiO2 grains on the polymer electrolytes and the effect of gamma-radiation from a Co-60 source were studied by small-angle X-ray scattering (SAXS) simultaneously recorded with differential scanning calorimetry (DSC) at the synchrotron ELETTRA. Impedance spectroscopy was also performed. The above-mentioned treatments greatly enhanced the conductivity of the polymer electrolyte. A room temperature conductivity increase of up to two orders of magnitude was achieved. The addition of nanograins increased the conductivity more than can be ascribed to the changes in crystallinity, possibly because of interactions of anions with nanograins. It is observed that the brittleness of the gamma-irradiated electrolyte was also reduced by nanograins. (c) 2007 The Electrochemical Society.