Electrical properties of gadolinia doped ceria electrolytes fabricated by infiltration aided sintering
By Sındıraç, Can; Büyükaksoy, Aligül; Akkurt, Sedat
Published in Solid State Ionics
2019
Abstract
Common solid oxide fuel cell (SOFC) electrolyte materials (e.g., gadolinia doped ceria – GDC) demand temperatures exceeding 1400 °C for densification by conventional solid state sintering. It is very desirable to reduce the densification of the SOFC electroltytes to i) avoid microstructural coarsening of the composite anode layers, which are co-sintered with the electolyte layer in the anode supported SOFC fabrication scheme and ii) reduce energy consumption during SOFC manufacturing. We have recently demostrated a novel infiltration-aided sintering route to densify GDC ceramics at 1200 °C. In the present work, we present the electrical properties of GDC ceramics fabricated thusly. Comparison of high density (≥95%) samples fabricated by conventional or infiltration-aided sintering reveal that at 700 °C, similar total electrical conductivities are obtained, while at 300 °C, specific grain boundary resistivity is smaller in the latter. Bulk (grain) conductivity is higher in porous GDC ceramics (relative density ≤ 90%) fabricated by infiltration-aided sintering than the conventionally sintered ones with similar porosities. Finally, open circuit voltage of 0.84 V at 700 °C, obtained under dilute hydrogen and stagnant air conditions suggests that GDC ceramics densified by infiltration-aided sintering are suitable for use as SOFC electrolytes.