Mo-doped BaCe_0?9Y_0?1O_3- proton-conducting electrolyte at intermediate temperature SOFCs. Part I: Microstructure and electrochemical properties

Researchers' interest in proton-conducting reversible solid oxide cells (RSOCs) is growing due to their distinct benefits. In the present work, single-phase BaCe0.9-xMoxY0.1O3-delta (x = 0, 0.025, 0.05, 0.1, 0.2) electrolyte is prepared via sol-gel method and sintered at 1400 degrees C for 10 h. Optimal density, structure, composition, electrochemical performance, and thermal stability are confirmed via SEM, XRD, EDS, XPS, FTIR, EIS, and TGA/DSC. The conductivity of the grain interior and boundaries between 127 and 727 degrees C is reported for the first time in SOFC studies. The BaCe0 center dot 875Mo0 center dot 025Y0 center dot 1O3-delta sample shows a grain interior conductivity of 1.3 x 10(-3) S cm(-1) at 707 degrees C with grain interior activation energy of 0.75 eV (127-727 degrees C), and a grain boundary activation energy of 0.85 eV (380-727 degrees C), 0.43 eV (167-357 degrees C) in air atmosphere, respectively. BaCe0 center dot 875Mo0 center dot 025Y0 center dot 1O3-delta showed extreme stability for 300 h, and thus can be considered suitable for an efficient protonic conductor at intermediate temperatures. (c) 2023 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.