Fabrication and characterization of Ca2+, Sr2+, Ba2+, Sm3+, and La3+ co-doped ceria-based electrolyte powders for low-temperature anode-supported solid oxide fuel cells

In this study, CeO2-based electrolytes are synthesized by a sol-gel method. Ce0.8Sm0.2O1.9, Ce0.8Sm0.15Ca0.05O1.875, Ce0.8Sm0.15Ca0.025Sr0.025O1.875 (S15CS05DC), Ce0.8Sm0.15La0.05O1.9, (La0.77Sr0.2Ba0.03)(0.15)Ce0.85O1.908, and (La0.77Sr0.2Ba0.03)(0.2)Ce0.8O1.877 specimens are prepared at sintering temperature 1300 degrees C for either 2 h or 4 h. The microstructures and electrical properties of the electrolytes are analyzed using X-ray diffraction, scanning electron microscopy, and alternating current (AC) impedance spectroscopy. All samples are cubic fluorite structure. It is found that while Ca2+ and Sr2+ contribute to grain growth, Sm3+ and La2+ inhibit it. The conductivity increases with temperature in a linear manner and reaches approximately 0.16 S.cm(-1) at 800 degrees C for the 4 h-sintered S15CS05DC sample. Six anode-supported cells are fabricated and tested at 600 degrees C-800 degrees C. Cell-C has the highest maximum power density (0.96 W.cm(-2)) at 800 degrees C. It is also found that ohmic resistance predominantly determines the total cell resistance at temperatures above 700 degrees C. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.