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Mechanism of La0.6Sr0.4Co0.2Fe0.8O3 cathode degradation

Published online by Cambridge University Press:  31 July 2012

Dongjo Oh ,
Danijel Gostovic  and
Eric D. Wachsman
Dongjo Oh
Affiliation:
Department of Materials Science and Engineering, University of Florida, Gainesville, Florida 32611
Danijel Gostovic
Affiliation:
Department of Materials Science and Engineering, University of Florida, Gainesville, Florida 32611
Eric D. Wachsman*
Affiliation:
University of Maryland Energy Research Center, University of Maryland, College Park, Maryland 20742
*
a)Address all correspondence to this author. e-mail: ewach@umd.edu
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Abstract

Elemental enrichment behavior on the surface of La0.6Sr0.4Co0.2Fe0.8O3 (LSCF) was investigated in order to understand potential degradation mechanism of solid oxide fuel cell cathodes. Surface morphological changes were examined using scanning electron microscopy after heat treatment in the temperature range of 600–900 °C. Submicron-sized precipitates were formed on grain surfaces after heat treatment. Their shapes appeared to be aligned along the surface orientations of the underlying grains. Auger electron spectroscopy and transmission electron microscopy characterization revealed that the precipitate was strontium (Sr)-oxygen (O) based. The formation of Sr–O precipitates was found to increase with increasing temperature and oxygen partial pressure. A defect chemistry model is presented based on the observed phenomena.

Type
Articles
Information
Journal of Materials Research , Volume 27 , Issue 15: Focus Issue: Advanced Materials for Fuel Cells , 14 August 2012 , pp. 1992 - 1999
Copyright
Copyright © Materials Research Society 2012

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