Cerium and Gadolinium co-doped perovskite oxide for a protonic ceramic fuel cell cathode

Proton-conducting ceramic fuel cells (PCFCs) show unique advantages over oxygen-ionic- conducting counterparts at intermediate and low temperatures, which have attracted significant attention worldwide in recent years. A critical issue for world-spread applications is inadequate performance due to the lack of appropriate cathodes for PCFCs. Here, cubic perovskite BaCO0.4Fe0.5-xCe0.1RexO3-delta (Re=Y, Gd x = 0, 0.1) materials are successfully synthesized and evaluated as the cathode in the PCFCs based on BaCe0.7Zr0.1Y0.1Yb0.1O3-delta as an electrolyte material. The Y- or Gd-doped perovskite BaCo0.4Fe0.4Ce0.1Y0.1O3-delta (BCFCeY), BaCo0.4Fe0.4Ce0.1Gd0.1O3-delta (BCFCeG) exhibit larger lattice parameters, and higher electro- catalytic activity comparing to their parent oxide BaCo0.4Fe0.5Ce0.1O3-delta (BCFCe). Among them, BCFCeG shows the best performance. The single cell with BCFCeG as the cathode material exhibits an interfacial polarization resistance as low as 0.12 Omega cm(2) and delivers a promising peak power density of 504 mW cm(-2) at 600 degrees C, while the BCFCe-based cell achieves only 437 mW cm(-2) at 600 degrees C. The X-ray diffraction (XRD) results show good chemical compatibility for BCFCeG below 1050 degrees C. Moreover, it shows favorable stability in CO2-containing environment. This work confirms that BCFCeG could be a promising cathode for PCFCs. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.