Enhancement of the ionic conductivity of mixed calcia/yttria stabilized zirconia

Abstract A ZrO 2 -based electrolyte, stabilized with 6 mol% CaO and 4 mol% Y 2 O 3 was synthesized. This electrolyte consists of a single phase fluorite-type solid solution with cubic symmetry and exhibits a uniform microstructure. In the temperature range 1273–1673 K, the direct current (DC) conductivity of this electrolyte is higher than that of 12 mol% CaO-stabilized ZrO 2 and comparable to that of 8 mol% Y 2 O 3 -stabilized ZrO 2 , prepared with the same processing procedure. It was suggested, by comparing the electrical behaviors of both binary systems ZrO 2 –CaO and ZrO 2 –Y 2 O 3 , that the enhancement of the ionic conductivity of mixed CaO/Y 2 O 3 -stabilized ZrO 2 at high temperature can be attributed to the increase in the concentration of the oxygen vacancies with weaker association energies.