Framtidens energiteknik

Abstract

The thermal properties and ionic conductivity of CsH2PO4 and the nanocomposites CsH2PO4-AL2O3 and CsH2PO4-TiO2 were measured, using various concentrations of Al2O3 and TiO2 nanoparticles. The enthalpies and onset temperatures of the proton conducting (superprotonic) phase transition of the substances were measured using direct scanning calorimetry. Ionic conductivities were measured through impedance spectroscopy. The results of all measurements, which were mainly performed in the temperature range 150-250 C, were then evaluated with their usefulness for fuel cell applications in mind. It was found that the thermal stability of CsH2PO4 can be improved by the addition of both Al2O3 and TiO2 nanoparticles. Also it was found that composites having 30% molar concentration of TiO2 nanoparticles retain the ionic conductivity of CsH2PO4, and that a 15% concentration slightly increases it. The ionic conductivity decreased however when using 50% and 70% molar concentration of TiO2. When adding Al2O3 nanoparticles, a lowered ionic conductivity was seen for all concentrations.