The effect of the sintering parameters on the structure and oxygen ion conductivity of Y2O3–ZrO2–CeO2 ceramics

Abstract

Yttria and zirconia co-doped ceria ceramics is a promising material for solid electrolytes for intermediate-temperature solid oxide fuel cells (IT-SOFC). The ionic conductivity of ceramics significantly depends on Ce 3+admixture presence, which can be controlled by heat treatment regimes. In the current study we report the detailed electrochemical and structural study of 10Y2O3-30ZrO2-60CeO2 ceramics manufactured via two-step sintering approach. The effects of the second sintering step on the phase composition, homogeneity of components distribution, grain growth and the microstructures of ceramics wereinvestigated via XRD, SEM, Raman spectroscopy techniques. Special attention was paid to valence state of cerium ions, which was examined via XPS. Using impedance spectroscopy it was shown that ternary ceramics possesses ionic conductivity up to 2.09·10−3 S/cm at 973 ​K in the N2 atmosphere and at the residual oxygen partial pressure no more than 10−3 atm.

Keywords

• IT-SOFC
• Ceria ceramics
• impedance spectroscopy
• Raman spectroscopy
• Freeze-drying