The processes limiting the performance of solid oxide fuel cell (SOFC) were examined for composite cathodes made by infiltrating La0.8Sr0.2FeO3-d (LSF) into porous yttria-stabilized zirconia (YSZ). Impedance spectra performed on symmetric cells calcined to 1123 K consisted of a single arc with a polarization resistance of 0.3 O cm2 at 973 K in air. The higher impedance of cells deactivated by calcination to 1373 K could be attributed to an additional low-frequency surface process. The addition of a conformal oxide coating of less than 1 nm in thickness further deactivated the LSF-YSZ cathode. At 873 K, the polarization resistance of Al2O3-coated cells increased by almost an order of magnitude. This deactivation was reversible; performance could be restored by a heat treatment that caused the conformal oxide coating to disintegrate.

Understanding surface reactions in SOFC cathodes prepared by infiltration

244th National Meeting (2012)

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