Relative Comparison of Cathode Polarizations in Solid Oxide Fuel Cells Using the Spreading Concept in AC 2 Point Impedance Spectroscopy |
Byung-Kook Lee, Eui-Hyun Kim, Jin-Ha Hwang |
Department of Materials Science and Engineering, Hongik University |
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ABSTRACT |
A modified two-point impedance spectroscopy technique exploits the geometric constriction between an electrolyte and a cathode with an emphasis on semispherical-shaped electrolytes. The spatial limitation in the electrolyte/electrode interface leads to local amplification of the electrochemical reaction occurring in the corresponding electrolyte/electrode region. The modified impedance spectroscopy was applied to electrical monitoring of a YSZ ($Y_2O_3$-stabilized $ZrO_2$)/SSC ($Sm_{0.5}Sr_{0.5}CoO_3$) system. The resolved bulk and interfacial component was numerically analyzed in combination with an equivalent circuit model. The effectiveness of the "spreading resistance" concept is validated by analysis of the electrode polarization in the cathode materials of solid oxide fuel cells. |
Key words:
Fuel Cells, Cathodes, Impedance Spectroscopy, Interfaces, Electrochemical Polarization |
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