engleski

IN SITU SAXS/DSC/WAXD STUDY OF POLYMER ELECTROLYTE FOR Zn RECHARGEABLE NANOSTRUCTURED GALVANIC CELLS

Polymer electrolytes as nanostructured materials are very attractive components for batteries and opto-electronic devices. Environment friendly galvanic cells as well as solar cells of the second generation are to be constructed with nanocomposite polymer as electrolyte. In our study, (PEO)8ZnCl2 polymer electrolytes were prepared from PEO and ZnCl2. The nanocomposites (PEO)8ZnCl2 themselves contained TiO2, Al2O3, MgO, ZnO and V2O5 nanograins. In this work, the influence of the Al2O3, MgO and V2O5 nanograins to the morphology and ionic conductivity of the nanocomposite was systematically studied by transmission small-angle X-ray scattering (SAXS) simultaneously recorded with wide-angle X-ray diffraction (WAXD) and differential scanning calorimetry (DSC). The SAXS/DSC/WAXD measurements yielded insight into the temperature-dependent changes of the grains of the electrolyte. The heating and following cooling rate was 1 °C/min. Figure 1 shows the SAXS, WAXS and DSC results obtained from polymer electrolyte nanocomposite with three nanofillers. The evolution of the average radii of the grain sizes obtained from the Guinier approximation is compared to the corresponding DSC and WAXD spectra behavior. In the heating cycle the superionic phase transition can be seen as the sudden drop of the nanograin sizes at the phase transition temperature. In the cooling part a hysteresis can be seen as the phase transition occurs at lower temperature. The endothermic and exothermic peaks found in DSC during the same temperature cycle follow the sudden changes in the average nanograin sizes as obtained from the SAXS measurements and the intensity drops in the WAXD spectra. There are two trends in SAXS in the heating cycle: first an increasing of the grain size up to 64.1°C and then a sudden drop at this phase transition temperature.

SAXS/DSC/WAXD; POLYMER ELECTROLYTE; NANOSTRUCTURED GALVANIC CELLS

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