Artículo
Stabilization of the cubic perovskite in the system La1-xBa xCo1-yFeyO3-δ (0.7 ≤ x ≤ 0.9) and its electrochemical performance as cathode materials for intermediate-temperature solid oxide fuel cells
Fecha de publicación:
01/02/2014
Editorial:
Elsevier Science
Revista:
Journal of Power Sources
ISSN:
0378-7753
Idioma:
Inglés
Tipo de recurso:
Artículo publicado
Clasificación temática:
Resumen
The effects of the substitution of Co by Fe on the crystal chemistry and electrode reaction of the system La1-xBaxCo 1-yFeyO3-δ (0.7 ≤ x ≤ 0.9), are investigated. The incorporation of Fe stabilizes the cubic perovskite and suppresses the structural transformation of La1-xBa xCoO3-δ from a metastable cubic perovskite to a hexagonal phase below 900 C. The linear expansion decreases with the replacement of Co by Fe. The lowest expansion coefficient value, α ∼ 20.5 × 10-6 K-1, was obtained for the samples with Fe content y = 0.6. AC impedance spectroscopy measurements on symmetrical cells reveal the presence of an intermediate (IF) and a low (LF) frequency contributions at T ≥ 600 C. The LF arc varies with the pO2, at 700 C, according to a power law with exponent n = -1, indicating oxygen diffusion through the porous of the electrode. The minimum Rp value (0.6 cm2 at 600 C) was obtained for La0.3Ba0.7Co0.6Fe 0.4O3-δ. At constant temperature, T = 750 C, only the IF contribution varies at a rate of 3 × 10-4 cm2 h-1, while the LF contribution remains constant. Experimental data suggest the growth of the IF arc is caused by the mismatch in the expansion coefficients of the electrode and electrolyte.
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Articulos(CCT - PATAGONIA NORTE)
Articulos de CTRO.CIENTIFICO TECNOL.CONICET - PATAGONIA NORTE
Articulos de CTRO.CIENTIFICO TECNOL.CONICET - PATAGONIA NORTE
Articulos(IFISUR)
Articulos de INSTITUTO DE FISICA DEL SUR
Articulos de INSTITUTO DE FISICA DEL SUR
Citación
Martinez, Cristian Fabricio; Prado, Fernando Daniel; de Florio, Daniel Zanetti; Caneiro, Alberto; Stabilization of the cubic perovskite in the system La1-xBa xCo1-yFeyO3-δ (0.7 ≤ x ≤ 0.9) and its electrochemical performance as cathode materials for intermediate-temperature solid oxide fuel cells; Elsevier Science; Journal of Power Sources; 247; 1-2-2014; 264-272
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