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

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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.

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Acknowledgment

The author thanks Junghoon Jang for operating low-angle XRD and Eric Lambert for AES analysis. This work was supported by the Florida Institute for Sustainable Energy.

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Authors and Affiliations

  1. Department of Materials Science and Engineering, University of Florida, Gainesville, Florida, 32611, USA

    Dongjo Oh & Danijel Gostovic

  2. University of Maryland Energy Research Center, University of Maryland, College Park, Maryland, 20742, USA

    Eric D. Wachsman

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  1. Dongjo Oh
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  2. Danijel Gostovic
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  3. Eric D. Wachsman
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Correspondence to Eric D. Wachsman.

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Oh, D., Gostovic, D. & Wachsman, E.D. Mechanism of La0.6Sr0.4Co0.2Fe0.8O3 cathode degradation. Journal of Materials Research 27, 1992–1999 (2012). https://doi.org/10.1557/jmr.2012.222

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