AC impedance behavior of a practical-size single-cell SOFC under DC current

Akihiko Momma, Yasuo Kaga, Kiyonami Takano, Ken Nozaki, Akira Negishi, Ken Kato, Tohru Kato, Toru Inagaki, Hiroyuki Yoshida, Kei Hosoi, Koji Hoshino, Taner Akbay, Jun Akikusa, Masaharu Yamada, Norihisa Chitose

    Research output: Contribution to journalArticlepeer-review

    27 Citations (Scopus)

    Abstract

    AC impedance measurements were carried out using practical-size planar disc-type SOFC which employs lanthanum gallate as a solid electrolyte. The data were obtained under practical conditions of gas flow rate and DC current. Under these conditions, the gas conversion impedance (GCI), which originates from the change of the electromotive force (EMF) caused by the change in anodic gaseous concentrations along the flow direction, was observed in the low-frequency range of the data obtained. The overlapping impedance together with GCI on the low-frequency arc was also estimated. Experimentally obtained GCI was in good agreement with that calculated. It was concluded that GCI was predominant in the impedance data obtained under practical conditions. The shift of the high-frequency intercept in the complex impedance diagrams was shown to appear as a result of the change in the distribution of gaseous composition in the anode. The dependency of the low-frequency arc on temperature was also shown, and it was assumed that the overlapped impedance varies as the temperature changes. The validity of the impedance measurement, as a diagnostic means to evaluate the gas flow in SOFC stack, was suggested.

    Original languageEnglish
    Pages (from-to)87-95
    Number of pages9
    JournalSolid State Ionics
    Volume174
    Issue number1-4
    DOIs
    Publication statusPublished - Oct 29 2004

    All Science Journal Classification (ASJC) codes

    • Chemistry(all)
    • Materials Science(all)
    • Condensed Matter Physics

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