Enhanced electrical conductivity of zirconia-scandia with niobia addition

Abstract

The electrical conductivity and the crystalline structure of zirconia-10 mol% scandia-x mol% niobia solid electrolytes were investigated for x=0.25, 0.50 and 1.00 mol%. Dense specimens with relative densities higher than 95% were obtained by solid state reaction and sintering at 1500ºC for 5 h. Full stabilization of the cubic structure at room temperature was obtained for compositions with x=0.50 and 1.00, whereas for x=0.25 cubic and rhombohedric structures coexist. The electrical conductivity determined by impedance spectroscopy is of the same order of magnitude as that of the parent solid electrolyte (zirconia-10 mol% scandia) in the high temperature range (above 600ºC). The isothermal conductivity of the solid electrolyte with x=0.50 mol% niobium oxide remains constant up to 100 h at 600ºC.