Ionic Conduction Behavior in SmxNd0.15 − xCe0.85O2 − δ

• Grain conductivity decreases marginally on increasing x in SmxNd0.15-xCe0.85O2-δ.
• Co-doping of Sm3+ and Nd3+ improve the grain boundary conductivity in ceria.
• The Ea determined for the σgb5 for all the tested co-doped compositions are comparable.

The effect of varying co-doping ratios on the grain and grain boundary conductivity is evaluated in the SmxNd0.15-xCe0.85O2-δ system. A slight decline in the grain conductivity is found on replacing Sm3+ with Nd3+ in SmxNd0.15-xCe0.85O2-δ. Nevertheless, the activation energy values for grain conductivity are comparable for all the compositions. The specific grain boundary conductivity calculated at lower temperatures, is found to be nearly 3 orders of magnitude smaller than the grain conductivity. Further, a wide variation in specific grain boundary conductivity data is observed across various tested compositions, with Sm0.10Nd0.05Ce0.85O2-δ exhibiting the highest conductivity. The high specific grain boundary conductivity contributes towards high total conductivity in this composition.