ELECTRICAL PROPERTIES OF INDIUM AND YTTRIUM-DOPED BARIUM CERATE-BASED COMPOUNDS FOR USE AS CERAMIC FUEL CELL ELECTROLYTES

摘要

The aim of this work is to compare the electrical properties of BaCe0.85Y0.15O3-delta (BCY15), BaCe0.70In0.30O3-delta (BCI30) and a composite material consisting of 30% vol. BCY15 and 70% vol. Ce0.85Y0.15O2-delta (YDC15). BCY15 and YDC15 were synthesized by co-precipitation, whereas BCI30 was obtained using the solid-state reaction method. Pellets were initially formed from powders at 5 MPa, after which they were isostatically pressed at 250 MPa and sintered at 1500 degrees C. Electrochemical impedance spectroscopy (EIS) was used to determine the electrical properties of the samples in both air (p(o2) = 0.021 MPa) and Ar-5%H-2 atmospheres. In the temperature range 200-400 degrees C in air atmosphere the highest conductivity values were determined for BCY15 (5,22.10(-5) - 2.74.1(-3) S/cm). On the other hand, the electrical conductivity values obtained for Y70B30 in both atmospheres between 200 and 550 degrees C are in the order of magnitude of 10(-7) - 10(- 3) S/cm. Consequently, it can be concluded that the compounds exhibit significant H+ and O-2 electrical conductivity at temperatures above 500 degrees C, which indicates the possibility for their potential use as ceramic fuel cell electrolytes.