Electrical conductivity of Sm-doped CeO2 electrolyte produced by two-step sintering

Samarium-doped CeO2 (SDC) compounds are good candidates for application in intermediate temperature solid oxide fuel cells (IT-SOFCs), where appropriate densification would lead to increased grain and grain boundary conductivity. In the present work, SDC containing 20 and 30 mol% samarium were prepared by a combined process of mechanical alloying and heat treatment. The dense sintered body was obtained by two-step sintering (TSS) and conventional sintering (CS) methods. The products were characterized by SEM, XRD and impedance spectroscopy in the temperature range of 400–700 °C. TSS of the powders containing 20 mol% samarium resulted in the enhancement of electrical conductivity and significant suppression of grain growth. Grain boundary resistivity was reduced with decreasing the grain sizes.

► Nearly full-dense structure of SDC ceramics was obtained by two-step sintering method.
► Conductivity was improved in two step sintering 2SDC samples.
► Schottky barrier height (Δϕ0) for samples from impedance data was calculated.