Chemical stability and electrical properties of Ba1-xCaxCe0.8Gd0.2O3-delta (0 <= x <= 0.06) proton conductor

The effect of Ca content on chemical stability and electrical properties of Ba1-xCaxCe0.8-Gd0.2O3-delta (BCCG, 0 <= x <= 0.06) proton conducting electrolyte is investigated in this work. The BCCG pellets were fabricated via a solid-state reaction method and high-temperature sintering at 1600 degrees C for 10 h in air. In XRD patterns, BCCG exhibited an orthorhombic phase, and the diffraction peaks of calcium-modified BaCe0.8Gd0.2O3-delta (BCG)-based samples shif-ted toward the high-angle side compared to BCG, indicating that Ca2+ occupies the A site. The chemical stability showed that adding a small amount of Ca2+ improves the stability against water while it deteriorates the stability in CO2-containing atmosphere. The highest conductivity was obtained for 1% Ca substitution (x 1/4 0.01, BCCG1), where it increased from 1.1 x 10(-3) to 2.8 x 10(-3) S cm(-1) at 400 degrees C and from 1.7 x 10(-2) to 3.1 x 10(-2) S cm(-1) at 800 degrees C compared to that of X = 0. The partial conductivities were greater for BCCG1 compared with BCG material. Proton conductivity was dominant for BCCG1 sample at 600 degrees C. (c) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.