Performance of BaZrO3 based Proton Conductors as an Electrolyte for Intermediate Temperature Operating SOFC

Abstract

Investigative results of Y concentration dependence of total conductivity, and testing results of self-supported cells, gave us knowledge to realize intermediate temperature operating SOFCs using Y-doped BaZrO3 proton conductors. An increase of Y concentration improved electrical properties of grain boundaries drastically. As a result, total conductivity of a 15mol% Y doped BaZrO3 sample in wet air and wet Ar showed 5mScm-1 at 400oC. The performance of the self-supported cells was very low because of high electrolyte resistance caused by those thicknesses. Open circuit voltage (OCV) was over 1V in the temperature range of 600oC to 400oC in spite of low ionic transparent number in wet air at 600oC. Degradation of electrolytes was not observed during tests. From those results, electrode-supported cells using Y-doped BaZrO3 will show sufficient cell performance for intermediate temperature SOFCs.