Elektronische und ionische Leitfaehigkeit von SrCeO_3 in reduzierender Atmosphaere

Abstract

The creates, doped with trivalent rare earth ions, exhibits remarkable high protonic conductivity in wet and hydrogen containing atmospheres and at temperatures between 600 C-900 C, which are interesting for various applications like fuel cells and gas sensors. The generation of electronic defects under high and very low oxygen partial pressures leads to an increase of the electronic conductivity under this conditions and limit the performance of technical devices. The main attention was therefore focused on the investigation and separation of the partial conductivities. In order to characterise the electronic conduction, measurements using selective blocking electrodes to separate the ionic and the electronic partial conductivity has been applied. The used technique equals a Hebb-Wagner polarisation experiment. The aim of our investigation was the analysis of the conditions in dry and wet hydrogen and oxygen atmosphere in the temperature range of 700-900 C, corresponding to the extreme requirements by operating a fuel cell. (orig./MM)Available from FIZ Karlsruhe / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman