Electrochemical performance and degradation of (La0.6Sr0.4)0.99CoO3−δ as porous SOFC-cathode

This paper shows that measured impedance in porous (La0.6Sr0.4)0.99CoO3 - delta cathodes can be dependent on both gas diffusion and electrode kinetics at temperatures above 700 deg C or below ambient pO2s if electrode kinetics are fast. The reaction mechanism is discussed on the basis of measured te...

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Bibliographic Details
Published in:Solid state ionics 2008-09, Vol.179 (27-32), p.1422-1426
Main Authors: Hjalmarsson, Per, Søgaard, Martin, Mogensen, Mogens
Format: Article
Language:English
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Summary:This paper shows that measured impedance in porous (La0.6Sr0.4)0.99CoO3 - delta cathodes can be dependent on both gas diffusion and electrode kinetics at temperatures above 700 deg C or below ambient pO2s if electrode kinetics are fast. The reaction mechanism is discussed on the basis of measured temperature- and pO2-dependences. The degradation was found to be related exclusively to the electrode kinetics and measured about 0.5-1.5 mOmega cm2 days- 1 depending on temperature with a higher rate measured in moisturised air. We speculate on degradation mechanism that involves formation of strontium hydroxides at catalytically active oxygen vacancy sites at the electrode surface.
ISSN:0167-2738
DOI:10.1016/j.ssi.2007.11.010