Study of the mechanisms of O2-reduction and degradation operating on La0.5-XPrxBa0.5CoO3-δ cathodes for SOFCs
The oxygen reduction mechanism and time evolution behavior were studied for porous La0.5-xPrxBa0.5CoO3-δ (LPBC) electrodes deposited onto Ce0.9Gd0.1O1.95 electrolytes. Electrochemical impedance spectroscopy (EIS) measurements, performed between 400 and 800 °C as a function of pO2, show that the elec...
| Autores: | , , , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2017 |
| País: | Argentina |
| Institución: | Consejo Nacional de Investigaciones Científicas y Técnicas |
| Repositorio: | CONICET Digital (CONICET) |
| Idioma: | inglés |
| OAI Identifier: | oai:ri.conicet.gov.ar:11336/58231 |
| Acceso en línea: | http://hdl.handle.net/11336/58231 |
| Access Level: | acceso abierto |
| Palabra clave: | 3d Tomography Sofc Cathode Barium Segregation Oxygen Reduction Reaction https://purl.org/becyt/ford/2.5 https://purl.org/becyt/ford/2 |
| Sumario: | The oxygen reduction mechanism and time evolution behavior were studied for porous La0.5-xPrxBa0.5CoO3-δ (LPBC) electrodes deposited onto Ce0.9Gd0.1O1.95 electrolytes. Electrochemical impedance spectroscopy (EIS) measurements, performed between 400 and 800 °C as a function of pO2, show that the electrochemical response is limited by O2-gas diffusion and surface reaction (O-surface exchange + O-ion diffusion). The time evolution of the cathode resistance at 700 °C in air shows an increase from 0.03 to 0.05 Ωcm2 after 280 h of testing. Three-dimensional (3D) tomographic using focused ion beam–scanning electron microscopy (FIB-SEM) showed little changes of microstructure after the ageing. The increase in resistance was explained by an increase in the amount of a water-soluble Ba-rich surface phase by a factor of 2, after ageing of the LPBC electrode, by an etching procedure coupled with inductively coupled plasma-optical emission spectrometry (ICP-OES). |
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