Conference paper · Journal article
Microstructural and electrical characterization of Nb-doped SrTiO3–YSZ composites for solid oxide cell electrodes
Ceramic processing, Fuel Cells and Solid State Chemistry Division, Risø National Laboratory for Sustainable Energy, Technical University of Denmark1
Fuel Cells and Solid State Chemistry Division, Risø National Laboratory for Sustainable Energy, Technical University of Denmark2
Risø National Laboratory for Sustainable Energy, Technical University of Denmark3
Nb-doped SrTiO3 (Sr1 − xTi0.9Nb0.1O3, x = 0.01 and 0.06, henceforth known as STN) and 8 mol% Y2O3 stabilized ZrO2 (8YSZ) composites were prepared by mixing them in different volume fractions between 10 vol.% and 50 vol.% of 8YSZ. The composites were compacted into pellets, sintered and evaluated for phase stability, phase compatibility, microstructure and electrical conductivity.
Microstructural analysis of the STN–8YSZ composites revealed that above 30 vol.% of 8YSZ, the percolation of the STN phase was extremely limited. Phase analysis by X-ray diffraction showed no clearly detectable secondary phases. However, microstructural analysis revealed segregation and formation of Nb enriched particles in the 50 vol.% 8YSZ composite.
Chemical analysis by energy dispersive spectroscopy (EDS) also showed the inter-diffusion of elements (especially Ti from STN and Zr from 8YSZ) from both phases on small length scales. The DC electrical conductivity measurements on the STN–8YSZ composites showed a drastic decrease in conductivity when more than 10 vol.% of 8YSZ was used in the composite.
The initial metallic conductivity behavior changed to semiconducting type for more than 30 vol.% 8YSZ, confirming the percolation limit observed by the microstructural analysis.
Language: | English |
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Year: | 2012 |
Pages: | 44-49 |
Proceedings: | E-MRS 2011 Spring Meeting IUMRS ICAM 2011 & E-MRS / MRS Bilateral Conference on Energy |
ISSN: | 18727689 and 01672738 |
Types: | Conference paper and Journal article |
DOI: | 10.1016/j.ssi.2011.11.025 |
ORCIDs: | Reddy Sudireddy, Bhaskar and Nielsen, Karsten Agersted |