Heterogeneous Zirconia-based Solid Electrolytes Obtained by Sintering TZP+YSZ Powder Mixtures

Abstract

Powder mixtures of 3%Y2O3 (3Y) and 8%Y2O3 (8Y) were used to obtain heterogeneous solid electrolytes with good sinterability and mostly fine grain sizes, without significantly undue effects on ionic conductivity. Samples with 8Y:3Y{less than or equal to}1:1 retain submicrometer grain sizes, with very rare grains above 1 {less than or equal to}m. Impedance spectroscopy was used to de-convolute the bulk and grain boundary contributions, and to analyze their dependence on the fraction of 3Y. Bulk conductivity and its activation energy vary gradually with increasing 8Y:3Y ratio. The lower grain boundary conductivity of homogeneous 3Y can be ascribed to a combination of finer grain sizes and also lower specific grain boundary conductivity. However, the grain boundary conductivity differences of heterogeneous samples obtained from 3Y+8Y mixtures can be mainly ascribed to differences in grain size. Specific grain boundary conductivity results of these heterogeneous solid electrolytes are similar to those obtained for homogeneous 8Y.