Electrical Properties of BaCeO3-Based Electrolytes for use in Dual Protonic Ceramic-Solid Oxide Fuel Cells

R. Gawel and K. Przybylski AGH University of Science and Technology, Faculty of Materials Science and Ceramics, Al. A. Mickiewicza 30, 30-059 Krakow, Poland

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Bulk samples consisting of BaCe0.85Y0.15O3-δ (BCY15) and Ce0.85Y0.15O2-δ (YDC15) compounds, mixed together in different ratios, were studied as potential electrolytes in dual protonic ceramic-solid oxide fuel cells and compared with non-composite BCY15 and YDC15. The microstructures of the sintered materials indicate that BCY15 exhibits the largest grains, whereas composites have greater visible porosity than the non-composite samples. From X-ray diffraction studies it follows that BCY15 and YDC15 consist mainly of one phase, whereas the composites are two-phase materials. Electrochemical impedance spectroscopy studies at different temperatures show that the composite materials are capable of conduction the order of 10-3 S/cm at temperatures above 500°C in a hydrogen-containing atmosphere. Furthermore, activation energy values of the conductivity determined for the composites in air atmosphere are between those obtained for BCY15 (Ea=0.590±0.017 eV) and YDC15 (Ea=1.132±0.008 eV). From this it follows that both phases of the composites influence the electrical conductivity of the materials. In conclusion, BCY15 and the BCY15-YDC15 composites show promise for future use as electrolytes in dual protonic ceramic-solid oxide fuel cells.

DOI: 10.12693/APhysPolA.131.1361 PACS numbers: composites, electrolytes, ceramics, electrochemistry