Some structural aspects of ionic conductivity in co-doped ceria-based electrolytes

Abstract

The sinters of co-doped ceria solid solutions with the formula of Ce 0.85Sm015-xRx01.9, where R = Y, Gd, Pr, Tb, 0 0.05 into solid solution Ce0. 85Sm0. 15-xRxO 1.9, R =Tb, Pr caused a decrease in the ionic transference numbertion below 1 due to an increase in partial electronic conduction. This fact limiting investigated co-doped terbia and samaria or samaria and praseodymia ceria-based solid solutions for the further application as oxide electrolytes in solid oxide fuel cells. The analysis of bulk and grain boundary values indicated that partial substitution of Sm3+ by Y3+ or Gd3+ caused slight improvements in the ionic conductivity of Ce0.85Sm0.15-.xRx01.9. The highest ionic conductivity was found for solid solution with chemical composition Ce0.85Sm0.1 Y0.05O1.9. The selected co-doped ceria samples were tested as solid electrolytes in solid oxide fuel cells operating in the intermediate temperature range500-750°C.