High performance Gd3+ and Y3+ co-doped ceria-based electrolytes for intermediate temperature solid oxide fuel cells

Co-doped ceria of Ce{sub 1-x}Gd{sub x-y}Y{sub y}O{sub 2-0.5x}, wherein x = 0.15 and 0.2, 0 {<=} y {<=} x, were prepared by glycine-nitrate method. Their structures and ionic conductivities were characterized by X-ray diffraction (XRD) and AC impedance spectroscopy (IS). All the electrolytes were found to be ceria-based solid solutions of fluorite type structures. Co-doping was found to effectively enhance the conductivity. In comparison to the singly doped ceria, the co-doped ceria showed much higher ionic conductivities at 673-973 K. At 773 K, the ionic conductivity of Ce{sub 0.8}Gd{sub 0.05}Y{sub 0.15}O{sub 1.9} is 0.013 S cm{sup -1} which is three times as high as that of Ce{sub 0.8}Gd{sub 0.2}O{sub 1.9}. These Gd{sup 3+}and Y{sup 3+} co-doped ceria are ideal electrolyte materials of intermediate temperature solid oxide fuel cells (SOFCs)