Microstructural and electrical characterization of Nb-doped SrTiO3–YSZ composites for solid oxide cell electrodes

Publication: Research - peer-reviewConference article – Annual report year: 2011

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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.

Original languageEnglish
JournalSolid State Ionics
Publication date2012
Volume216
Pages44-49
ISSN0167-2738
DOIs
StatePublished

Conference

ConferenceE-MRS 2011 Spring Meeting IUMRS ICAM 2011 & E-MRS / MRS Bilateral Conference on Energy
CountryFrance
CityNice
Period09/05/1113/05/11
CitationsWeb of Science® Times Cited: 7

Keywords

  • Electrical conductivity, Nb-doped SrTiO3, Diffusion, Ceramic electrode, Microstructure
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