SAXS/WAXS/DSC study of temperature evolution in nanopolymer electrolyte

Soft matter polymer electrolytes as nanostructured materials are very attractive components for batteries and for opto-electronic devices as a new generation of dye-sensitized solar cells. (PEO)₈ZnCl₂ polymer electrolytes were prepared from PEO and ZnCl₂. The nanocomposites (PEO)₈ZnCl₂/TiO₂ themselves contained TiO₂ nanograins. In this work, the influence of TiO₂ nanograins or the morphology and ionic conductivity of the nanocomposite was systematically studied by small-angle X-ray scattering (SAXS) simultaneously recorded with wide-angle X-ray scattering (WAXS) and differential scanning calorimetry (DSC) at the synchrotron ELETTRA. Shown by previous impedance spectroscopy measurements (IS), the room temperature conductivity of nanocomposite polymer electrolyte increased more than two times above 65 °C, relative to pure composites of PEO and salts. The SAXS/DSC measurements yielded insight into the temperature-dependent changes of the grains of the electrolyte as well as into the effects of heating and cooling rates. The crystal structure and temperatures of melting and crystallization of the nanosize grains was revealed by the simultaneous WAXS measurements.