The space charge density of 2–10mol% yttria-stabilized zirconia at the interface with a Au electrode was determined from differential capacity measurements at 748 to 848K. The O vacancy fraction in the space charge layer was calculated as function of bias potential, temperature and composition by fitting the data at positive bias potential to a Boltzmann-type equation. The vacancy concentration in the space charge layer increased with decreasing bias potential and reached a temperature-dependent maximum. This behaviour could be understood under the assumption that only a fraction of the O sub-lattice was available for O vacancy distribution. This volume fraction increased with temperature, with an associated thermal activation energy in the range of 0.27 to 0.46eV, depending upon the composition.

The Defect Structure of the Double Layer in Yttria-Stabilised Zirconia. M.G.H.M.Hendriks, J.E.ten Elshof, H.J.M.Bouwmeester, H.Verweij: Solid State Ionics, 2002, 154-155, 467-72