Conductivity and stability of cobalt pyrovanadate

Peter I Cowin, Rong Lan, Christophe TG Petit, Lei Zhang, Shanwen Tao

    Research output: Contribution to journalArticle

    8 Citations (Scopus)

    Abstract

    Cobalt pyrovanadate was successfully synthesised by a solid state route and the conductivity in both oxidising and reducing environments was determined for the first time. Impedance measurements between 300 °C and 700 °C in air determined that Co2V2O7 is an intrinsic semiconductor with activation energy of 1.16(3) eV. The conductivity in air reached a maximum of 4 × 10−4 S cm−1 at 700 °C. Semiconducting behaviour was also observed in 5% H2/Ar, albeit with a much smaller activation energy of 0.04(4) eV. Between 300 °C and 700 °C the conductivity ranged from 2.45 S cm−1 to 2.68 S cm−1, which is approaching the magnitude required for SOFC anode materials. Thermogravimetric analysis found a significant weight loss upon reduction of the compound. X-ray diffraction analysis, coupled with data from previous research, suggested compound degradation into Co2−xV1+xO4, CoO and VO. The redox instability and the low conductivity lead us to the conclusion that cobalt pyrovanadate is unsuitable for utilisation as an anode material for SOFCs although the conductivity is reasonable in a reducing atmosphere.

    Original languageEnglish
    Pages (from-to)4117-4121
    Number of pages5
    JournalJournal of Alloys and Compounds
    Volume509
    Issue number10
    Early online date31 Dec 2010
    DOIs
    Publication statusPublished - 10 Mar 2011

    Keywords

    • Conductivity
    • Cobalt pyrovanadate
    • Anode
    • Solid oxide fuel cell

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