Electrochemical response of several cathode configurations prepared with Ba0.5Sr0.5Co0.8Fe0.2O3-δ and Ce0.9Gd0.1O1.95 for IT-SOFC
The electrochemical response of Ba0.5Sr0.5Co0.8Fe0.2O3-δ (BSCF) electrodes prepared by an acetic acid-based gel route has been investigated by impedance spectroscopy (IS) as a function of temperature (400 ≤ T ≤ 900 °C) and oxygen partial pressure (1 × 10−3 ≤ pO2 ≤ 1 atm). Several electrode configura...
| Autores: | , , |
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| Formato: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2016 |
| País: | Argentina |
| Recursos: | Consejo Nacional de Investigaciones Científicas y Técnicas |
| Repositorio: | CONICET Digital (CONICET) |
| Idioma: | inglés |
| OAI Identifier: | oai:ri.conicet.gov.ar:11336/62155 |
| Acesso em linha: | http://hdl.handle.net/11336/62155 |
| Access Level: | acceso abierto |
| Palavra-chave: | Bscf Cathode Impedance Spectroscopy Sofc https://purl.org/becyt/ford/2.5 https://purl.org/becyt/ford/2 |
| Resumo: | The electrochemical response of Ba0.5Sr0.5Co0.8Fe0.2O3-δ (BSCF) electrodes prepared by an acetic acid-based gel route has been investigated by impedance spectroscopy (IS) as a function of temperature (400 ≤ T ≤ 900 °C) and oxygen partial pressure (1 × 10−3 ≤ pO2 ≤ 1 atm). Several electrode configurations were studied using Ce0.9Gd0.1O1.95 (GDC) as the electrolyte. These consisted of one BSCF layer (cell A), a BSCF layer with an intermediate porous GDC layer (cell B), and graded electrodes using a composite BSCF+GDC, with variations in the surface area of GDC (cells C and D). The optimum heat treatment for the electrode assemblages was determined to be around 850–900 °C. Analysis of the impedance spectra shows that at T ≥ 600 °C a low frequency (LF) contribution, associated to the gas phase diffusion is systematically the rate-limiting step. All the electrodes show an intermediate frequency (IF) arc related to mixed processes. For cells A and B, the IF response is related to the oxide ion transfer at the electrode/electrolyte surface and the charge transfer at the electrode surface, while for cells C and D the mixed process involves the charge transfer and the molecular oxygen dissociation at the electrode surface. |
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