Structural and microstructural stability of ceria – gadolinia electrolyte exposed to reducing environments of high temperature fuel cells†
* Corresponding authors
a CSIRO Energy Technology, Private Bag 33, Clayton South 3169, Victoria, Australia
E-mail:sukhvinder.badwal@csiro.au
b Australian Synchrotron, 800 Blackburn Road, Clayton 3168, Victoria, Australia
c Centre for Microscopy and Microanalysis, The University of Queensland, Brisbane 4072, Qld, Australia
Abstract
Doped CeO2 is widely used in intermediate temperature solidoxidefuel cells (500–650 °C) due to its high ionic conductivity, low reactivity to other cell components and ability to facilitate charge transfer reactions at the electrode/electrolyte interface. However, on exposure to hydrogen above 650 °C doped cerates can be reduced leading to catastrophic microstructure failure and loss of mechanical integrity. The effect of otherfuels such as C and CO on the stability of ceria based electrolytes remains largely unexplored despite the increased significance in developingfuel cells that operate on thesefuels. In this paper a systematic investigation has been carried out on the effect of carbon monoxide on the electrical conductivity, ionic transport, crystal structure and microstructure of Ce0.8Gd0.2O2−x, with particular emphasis on the mechanisms ofreduction and the long term stability of the material for use in a direct carbonfuel cell (DCFC) where this material will be exposed to a reducing environment containing little or no hydrogen. These investigations have been carried out at temperatures typically found during the operation of a DCFC (800 °C) and the results have been compared with similar investigation carried out in dry hydrogen atmosphere. A wide range of techniques includingsynchrotron X-ray powder diffraction, high resolution transmission andscanning electron microscopy, four-probe DC conductivity measurements and electrochemical impedance analysis have been used to investigate the structural, microstructural and electrical properties of Ce0.8Gd0.2O2−x exposed to the operating environments of a DCFC.
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Article information
- Article type
- Paper
- Submitted
- 03 May 2013
- Accepted
- 22 Jul 2013
- First published
- 24 Jul 2013
Permissions
Structural and microstructural stability of ceria – gadolinia electrolyte exposed to reducing environments of high temperaturefuel cells
S. P. S. Badwal, D. Fini, F. T. Ciacchi, C. Munnings, J. A. Kimpton and J. Drennan,J. Mater. Chem. A, 2013, 1, 10768DOI: 10.1039/C3TA11752A
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