Performance of lanthanum strontium manganite electrodes at high pressure

E. C. Thomsen, G. W. Coffey, L. R. Pederson, O. A. Marina

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    Abstract

    The high-pressure performance of lanthanum strontium manganite (LSM), LSM-zirconia, and LSM/ceria composite electrodes was studied by impedance spectroscopy and dc methods. Electrode resistances decreased in proportion to P(O2)1/2 for the LSM electrode in both cathodic and anodic directions to at least 10 MPa (∼100 atm), a decrease that was attributed to dissociative oxygen adsorption and related phenomena. For the LSM-20/zirconia composite electrode, resistances decreased in proportion to P(O2)1/4 across the entire pressure range considered. Two principal features appeared in the impedance spectra, one that showed a P(O2)1/4 dependence attributed to charge transfer reactions, and a smaller feature that was nearly pressure-independent, possibly due to transport in the zirconia portion of the composite. For the LSM-20/ceria composite electrode, resistances decreased as P(O2)0.3-0.4 at high pressure, depending on temperature. Two features appeared in the impedance spectra: one at low to intermediate frequency having a ∼P(O2)1/2 dependence and a second at high frequency having a ∼P(O2)1/4 dependence. These features are attributed to dissociative oxygen adsorption and to charge transfer reactions, respectively. Results suggest that cathodic losses can be substantially lowered by operation of solid oxide fuel cells at greater than ambient pressure.

    Original languageEnglish
    Pages (from-to)217-224
    Number of pages8
    JournalJournal of Power Sources
    Volume191
    Issue number2
    DOIs
    Publication statusPublished - 15 Jun 2009

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    Keywords

    • Cathode
    • LSM
    • Lanthanum manganite
    • Oxygen electrode
    • Pressure
    • Solid oxide fuel cell (SOFC)

    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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