Degradation of the electrical conductivity in stabilised zirconia systems: Part I: yttria-stabilised zirconia
- 作者：Haering ; C. ; Roosen ; A. ; Schichl ; H.
- 关键词：Solid oxide fuel cells ; 8YSZ and 10YSZ electrolytes ; Degradation of the ionic conductivity ; Ageing phenomenon ; Defect associates
- 刊名：Solid State Ionics
- 出版年：2005
- 期刊代码：96_01672738
- 类别：ch
- 出版时间：January 31, 2005
- 卷：176
- 期：3-4
- 页码：253-259
- 文件大小：333 K
摘要
Annealing at 1000 脗脗C reduces the electrical conductivity of 8 mol%yttria-stabilised zirconia (8YSZ), known as a good performing material for Solid Oxide Fuel Cells (SOFC) electrolytes. This decrease in electrical conductivity by ageing for 1000 h was not observed for doped zirconia with higher yttria contents. High-resolution XRD, neutron-diffraction and STEM were performed to get information of possible changes in the microstructure. Both, the electrical measurements and structural investigations of yttria-stabilised zirconia have been correlated. It is explained that the degradation was not caused by the phase change that occurs in samples with lower dopant content. The ageing effect of the electrical properties is interpreted by the presence of different defect associates present before annealing in all the doped zirconia specimens, or rather the transformation within these associates. This transformation also affects the observed structural change. A confirmation of this model of defect associates transformation is given in part II, wherein the scandia-stabilised system has been studied.