The Mechanism of Porous Sm0.5Sr0.5CoO3 Cathodes Used in Solid Oxide Fuel Cells

Michihisa Koyama, Ching Ju Wen, Takuya Masuyama, Junichiro Otomo, Hiroshi Fukunaga, Koichi Yamada, Koichi Eguchi, Hiroshi Takahashi

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Overpotentiul and ac impedance spectra were measured to construct a model to describe porous Sm1-xSrxCoO3 (SSC) cathodes for solid oxide fuel cells (SOFCs). Analysis of the impedance spectra revealed that there are three processes involved in the overall electrochemical reaction; (i) the adsorption/desorption process on the surface of the electrode, (ii) the ionic conduction in the bulk SSC, and (iii) the diffusion of oxygen in the gas phase. It was found that in air atmosphere, the reaction processes (i) and (ii) were dominant, while the diffusion process of gaseous oxygen was fast enough not to limit the overall reaction rate. A reaction model for the porous SSC cathodes used in SOFCs was proposed to determine the electrode resistance by taking processes (i) and (ii) into account. It was found that our model explained the experimental results well. These results suggested the possibility of using our model to describe the cathodes with high ionic conductivity and to design the high-performance cathode systematically. The validity of the analysis hy conventional equivalent circuit was also discussed.

Original languageEnglish
JournalJournal of the Electrochemical Society
Issue number7
Publication statusPublished - Jul 1 2001

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Renewable Energy, Sustainability and the Environment
  • Surfaces, Coatings and Films
  • Electrochemistry
  • Materials Chemistry

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    Koyama, M., Wen, C. J., Masuyama, T., Otomo, J., Fukunaga, H., Yamada, K., Eguchi, K., & Takahashi, H. (2001). The Mechanism of Porous Sm0.5Sr0.5CoO3 Cathodes Used in Solid Oxide Fuel Cells. Journal of the Electrochemical Society, 148(7).