Tri-doped ceria (M0.2Ce0.8O2-δ, M = Sm0.1, Ca0.05, Gd0.05) electrolyte for hydrogen and ethanol-based fuel cells

In recent scientific research, an interest has been gained significantly by rare earth metals such as cerium (Ce), samarium (Sm) and gadolinium (Gd) due to their use in fuel cells as electrolyte and catalysts. When used in an electrolyte, these materials lower the fuel cell's operating temperature compared to a conventional electrolyte, for example, yittria-stabilized zirconia (YSZ) which operates at a high temperature (>= 800 degrees C). In this paper, the tri-doped ceria, M0.2Ce0.8O2-delta (M = Sm-0.1, Ca-0.05, Gd-0.05) electrolyte powders was synthesized using the co-precipitation method at 80 degrees C. These dopants were used for CeO2 with a total molar ratio of 1 M. Dry-pressed powder technique was used to make fuel cell pellets from the powder and placed them in the furnace to sinter at 700 degrees C for 60 min. Electrical conductivity of such a pellet in air was 1.2 x 10>(-2) S cm(-1) at 700 degrees C measured by the ProboStat-NorECs setup. The crystal structure was determined with the help of X-ray diffraction (XRD), which showed that all the dopants were successfully doped in CeO2 . Raman spectroscopy and UV-VIS spectroscopy were also carried out to analyse the molecular vibrations and absorbance, respectively. The maximum open-circuit voltages (OCVs) for hydrogen and ethanol fuelled at 550 degrees C were observed to be 0.89 V and 0.71 V with power densities 314 mW cm(-2) and 52.8 mW cm(-2) , respectively. (C) 2018 Published by Elsevier B.V.