TY - JOUR
T1 - Study of La0.6Sr0.4Co1-xFexO3-δ (x = 0.2 & 0.8) Electrochemical Response as SOFC Cathodes and Its Relation with Microstructure
AU - Ascolani-Yael, J.
AU - Montenegro-Hernández, A.
AU - Liu, Q.
AU - Barnett, S. A.
AU - Mogni, L.
N1 - Funding Information:
The authors at Centro Atómico Bariloche aknowledge Alberto Baruj for the SEM images, the financial support of Comisión Nacional de Energía Atómica (CNEA), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Agencia Nacional de Promoción de Ciencia y Tecnología (AGNPCyT ANPCyT PICT 2016-2965) and Instituto Balseiro-Universidad Nacional de Cuyo. J. Ascolani-Yael is especially grateful to the Fulbright Program. The authors at North-western University gratefully acknowledge financial support from the National Science Foundation Ceramics program DMR-1912530.
Funding Information:
The authors at Centro Atómico Bariloche aknowledge Alberto Baruj for the SEMimages, the financial support of Comisión Nacional de Energía Atómica (CNEA), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Agencia Nacional de Promoción de Ciencia y Tecnología (AGNPCyT ANPCyT PICT 2016-2965) and Instituto Balseiro-Universidad Nacional de Cuyo. J. Ascolani-Yael is especially grateful to the Fulbright Program. The authors at Northwestern University gratefully acknowledge financial support from the National Science Foundation Ceramics program DMR-1912530.
Publisher Copyright:
© 2019 The Electrochemical Society.
PY - 2019
Y1 - 2019
N2 - This work presents the study of the O2-Reduction Reaction (ORR) by electrochemical impedance spectroscopy of La0.6Sr0.4Co0.8Fe0.2O3-δ and La0.6Sr0.4Co0.2Fe0.8O3-δ cathodes as a function of temperature and pO2. The combination of the impedance data, modeled with a Transmission Line Model, with the microstructural data obtained by FIB-SEM tomography, allowed to obtain and compare the chemical diffusion coefficients (Dchem), O2 equilibrium molar exchange rates (R0) and the oxygen surface exchange rates (kchem) for both compounds. The obtained values were, at 700°C in air, Dchem = 5.4.10-7 cm2 .s-1 and kchem = 1.4.10-6 cm. s-1 for La0.6Sr0.4Co0.2Fe0.8O3-δ, while Dchem = 2.6.10-6 cm2 .s-1 and kchem = 3.1.10-6 cm. s-1 were obtained for La0.6Sr0.4Co0.8Fe0.2O3-δ. The detailed analysis of these parameters as a function of pO2 (10-4 < pO2 ≤ 1) and temperature (500°C ≤ T ≤ 700°C) by means of the Adler-Lane-Steele model, adapted to a finite length porous electrode, allowed identifying the O-ion diffusion and surface exchange as processes co-limiting the ORR. From this analysis, a predominantly surface limited ORR was found for La0.6Sr0.4Co0.2Fe0.8O3-δ, changing to a more bulk limited ORR for La0.6Sr0.4Co0.8Fe0.2O3-δ, which has higher oxygen-vacancy concentration.
AB - This work presents the study of the O2-Reduction Reaction (ORR) by electrochemical impedance spectroscopy of La0.6Sr0.4Co0.8Fe0.2O3-δ and La0.6Sr0.4Co0.2Fe0.8O3-δ cathodes as a function of temperature and pO2. The combination of the impedance data, modeled with a Transmission Line Model, with the microstructural data obtained by FIB-SEM tomography, allowed to obtain and compare the chemical diffusion coefficients (Dchem), O2 equilibrium molar exchange rates (R0) and the oxygen surface exchange rates (kchem) for both compounds. The obtained values were, at 700°C in air, Dchem = 5.4.10-7 cm2 .s-1 and kchem = 1.4.10-6 cm. s-1 for La0.6Sr0.4Co0.2Fe0.8O3-δ, while Dchem = 2.6.10-6 cm2 .s-1 and kchem = 3.1.10-6 cm. s-1 were obtained for La0.6Sr0.4Co0.8Fe0.2O3-δ. The detailed analysis of these parameters as a function of pO2 (10-4 < pO2 ≤ 1) and temperature (500°C ≤ T ≤ 700°C) by means of the Adler-Lane-Steele model, adapted to a finite length porous electrode, allowed identifying the O-ion diffusion and surface exchange as processes co-limiting the ORR. From this analysis, a predominantly surface limited ORR was found for La0.6Sr0.4Co0.2Fe0.8O3-δ, changing to a more bulk limited ORR for La0.6Sr0.4Co0.8Fe0.2O3-δ, which has higher oxygen-vacancy concentration.
UR - http://www.scopus.com/inward/record.url?scp=85076083035&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85076083035&partnerID=8YFLogxK
U2 - 10.1149/2.0281916jes
DO - 10.1149/2.0281916jes
M3 - Article
AN - SCOPUS:85076083035
SN - 0013-4651
VL - 166
SP - F1301-F1307
JO - Journal of the Electrochemical Society
JF - Journal of the Electrochemical Society
IS - 16
ER -
