Electrochemical, structural and surface characterization of nickel/zirconia solid oxide fuel cell anodes in coal gas containing antimony

Olga A. Marina, Larry R. Pederson, Christopher A. Coyle, Edwin C. Thomsen, Ponnusamy Nachimuthu, Danny J. Edwards

    Research output: Contribution to journalArticle

    14 Citations (Scopus)

    Abstract

    The interactions of antimony with the nickel-zirconia anode in solid oxide fuel cells (SOFCs) have been investigated. Tests with both anode-supported and electrolyte-supported button cells were performed at 700 and 800 °C in synthetic coal gas containing 100 ppb to 9 ppm antimony. Minor performance loss was observed immediately after Sb introduction to coal gas resulting in ca. 5% power output drop. While no further degradation was observed during the following several hundred hours of testing, cells abruptly and irreversibly failed after 800-1600 h depending on Sb concentration and test temperature. Antimony was found to interact strongly with nickel resulting in extensive alteration phase formation, consistent with expectations based on thermodynamic properties. Nickel antimonide phases, NiSb and Ni5Sb2, were partially coalesced into large grains and eventually affected electronic percolation through the anode support. Initial degradation was attributed to diffusion of antimony to the active anode/electrolyte interface to form an adsorption layer, while the late stage degradation was due the Ni-Sb phase formation. Assuming an average Sb concentration in coal gas of 0.07 ppmv, a 500 μm thick Ni/zirconia anode-supported cell is not expected to fail within 7 years when operated at a power output of 0.5 W cm-2 and fuel utilization above 50%.

    Original languageEnglish
    Pages (from-to)4911-4922
    Number of pages12
    JournalJournal of Power Sources
    Volume196
    Issue number11
    DOIs
    Publication statusPublished - 1 Jun 2011

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    Keywords

    • Antimony adsorption
    • Coal gas contaminants
    • Ni/YSZ SOFC anode degradation mechanism
    • Nickel antimony interaction
    • Thermochemical calculations

    ASJC Scopus subject areas

    • Renewable Energy, Sustainability and the Environment
    • Energy Engineering and Power Technology
    • Physical and Theoretical Chemistry
    • Electrical and Electronic Engineering

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