Preparation and optimization of La0.6Sr0.4Fe1-yCoyO3-δ cathodes for intermediate temperature solid oxide fuel cells
It is shown in this work that a synthetic route based on the auto-combustion of an ethylene glycol-metal nitrate polymerized gel precursor can be efficiently used to easily produce a range of La0.6Sr0.4Fe1-yCoyO3-δ nanopowders at moderate temperatures. We have been able to determine on air-sintered...
| Autores: | , |
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| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2024 |
| País: | España |
| Institución: | Consejo Superior de Investigaciones Científicas (CSIC) |
| Repositorio: | DIGITAL.CSIC. Repositorio Institucional del CSIC |
| OAI Identifier: | oai:digital.csic.es:10261/375984 |
| Acceso en línea: | http://hdl.handle.net/10261/375984 |
| Access Level: | acceso abierto |
| Palabra clave: | Ferro-cobaltite cathodes electrochemical properties thermal expansion coefficients chemical compatibility |
| Sumario: | It is shown in this work that a synthetic route based on the auto-combustion of an ethylene glycol-metal nitrate polymerized gel precursor can be efficiently used to easily produce a range of La0.6Sr0.4Fe1-yCoyO3-δ nanopowders at moderate temperatures. We have been able to determine on air-sintered samples the effect of sintering temperature on the microstructure. At sintering temperatures as low as 1100 to 1200 °C, grains are well defined with a uniform round spherical morphology and have a homogeneous sub-micrometer size distribution showing a highly densified microstructure. The electronic conductivity and thermal expansion coefficients (TEC) of sintered LSFC samples have been determined according to the variation of Fe/Co composition. Both measures clearly increase with the Co content. These materials also must exhibit chemical stability with electrolytes, most commonly used for intermediate temperature solid oxide fuel cells (IT-SOFCs). In this way, the material obtained is optimized in terms of chemical homogeneity and good stoichiometric control, microstructural characteristics of sintered samples, and finally, the adequate cobalt content to avoid high TEC mismatch with other components of the SOFC. This is a crucial issue as it causes an important thermomechanical stress, promotes extensive microcraking and causes significant performance degradation. Finally, these cathodes must exhibit acceptable electrochemical parameters for use in IT-SOFC. |
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