Electrical conductivity of CeO2-doped YSZ

The electrical conductivity of [(ZrO2)1−x(CeO2)x](Y2O3)0.08 (x=0, 0.1, 0.2, and 0.3) was measured between 850 and 1000°C in a wide PO2 range. The PO2 independent ionic conductivity at high PO2 was replaced by the electronic conductivity at reducing atmosphere for x=0.2 and 0.3 and a conductivity maximum was shown above the ionic plateau. The observation was explained by an equation accommodating the proposed defect model. The rapid decrease of conductivity at low PO2 was attributed to the combined effect of the decrease of both the ionic and the electronic conductivity. The decrease of electronic conductivity was also contributed by both the decrease of concentration of hopping carriers and the accompanied decrease of the electron mobility. The electronic transference number (tel) was calculated from the fitted data and was shown to increase with increasing Ce content. The tel decreased after a maximum with decreasing PO2 for fixed Ce content.