Electrical conductivity of Ce0.8Gd0.2−xDyxO2−δ (0 ≤ x ≤ 0.2) co-doped with Gd3+ and Dy3+ for intermediate-temperature solid oxide fuel cells

High-quality nano-sized Ce0.8Gd0.2−xDyxO2−δ (0 ≤ x ≤ 0.2) powders are synthesized by a solution combustion process. The calcined powders are composed of a ceria-based single phase with a cubic fluorite structure and are nanocrystalline nature, i.e., 15–24 nm in crystallite size. The addition of an intermediate amount of Dy3+ (0.03 ≤ x ≤ 0.16) for Gd3+ in Ce0.8Gd0.2O2−δ decreases the electrical conductivity. On the other hand, the doping of a small amount of Dy3+ (0.01 ≤ x ≤ 0.02) and of a large amount of Dy3+ (0.17 ≤ x ≤ 0.19) leads to an increase in conductivity. The Ce0.8Gd0.03Dy0.17O2−δ shows the highest electrical conductivity (0.215 S cm−1) at 800 °C.

Research highlights
► High-quality nano-sized Ce0.8Gd0.2−xDyxO2−δ powders are synthesized by solution combustion process.
► The nanostructured features of calcined Ce0.8Gd0.2−xDyxO2−δ powders lower sintering temperature.
► Increasing Dy3+ content increases the grain size and density of Ce0.8Gd0.2−xDyxO2−δ.
► The maximum electrical conductivity (0.215 S cm−1) is obtained for Ce0.8Gd0.03Dy0.17O2−δ at 800 °C.