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

Bhaskar Reddy Sudireddy, Peter Blennow Tullmar, Karsten Agersted Nielsen

    Research output: Contribution to journalConference articleResearchpeer-review

    Abstract

    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
    Volume216
    Pages (from-to)44-49
    ISSN0167-2738
    DOIs
    Publication statusPublished - 2012
    EventE-MRS 2011 Spring Meeting IUMRS ICAM 2011 & E-MRS / MRS Bilateral Conference on Energy: Fuel Cells-Energy Conversion - Nice, France
    Duration: 9 May 201113 May 2011

    Conference

    ConferenceE-MRS 2011 Spring Meeting IUMRS ICAM 2011 & E-MRS / MRS Bilateral Conference on Energy
    CountryFrance
    CityNice
    Period09/05/201113/05/2011

    Keywords

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

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