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Impedance of the Surface Double Layer of LSCF/CGO Composite Cathodes: An Elementary Kinetic Model

Yurkiv, Vitaliy and Costa, Rémi and Ilhan, Zeynep and Ansar, Asif and Bessler, Wolfgang (2014) Impedance of the Surface Double Layer of LSCF/CGO Composite Cathodes: An Elementary Kinetic Model. Journal of The Electrochemical Society, 161 (4), F480-F492. Electrochemical Society, Inc.. DOI: 10.1149/2.070404jes ISSN 0013-4651

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Official URL: http://jes.ecsdl.org/cgi/doi/10.1149/2.070404jes

Abstract

We present a combined modeling and experimental study of electrochemical oxygen reduction at mixed-conducting composite LSCF/CGO solid oxide fuel cell (SOFC) cathodes. The developed kinetic model incorporates elementary heterogeneous chemistry and electrochemical charge-transfer processes at two different electrochemical double layers, transport in the porous composite electrode (ionic and electronic conduction, multi-component porous diffusion and convection) as well as gas supply. A full set of thermodynamic and kinetic parameters is developed. Experimentally, La0.6Sr0.4Co0.8Fe0.2O3-δ/Ce0.9Gd0.1O2-α composite electrodes embedded into a symmetrical cell with CGO electrolyte were characterized via electrochemical impedance spectroscopy. The model shows good agreement with experimental impedance data over the complete range of investigated conditions (temperature range 775 K–1075 K, frequency range 10 mHz–100 kHz). This allows a mechanistic interpretation of the origin of the three observed impedance features: (i) low frequency: transport in the gas supply (gas conversion), (ii) intermediate frequency: charge transfer and surface double layer at the LSCF/air interface, (iii) high frequency: charge transfer and electrical double layer at the LSCF/CGO interface.

Item URL in elib:https://elib.dlr.de/90456/
Document Type:Article
Title:Impedance of the Surface Double Layer of LSCF/CGO Composite Cathodes: An Elementary Kinetic Model
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Yurkiv, Vitaliyvitaliy.yurkiv (at) dlr.deUNSPECIFIED
Costa, Rémiremi.costa (at) dlr.deUNSPECIFIED
Ilhan, ZeynepDLRUNSPECIFIED
Ansar, AsifUNSPECIFIEDUNSPECIFIED
Bessler, Wolfgangwolfgang.bessler (at) hs-offenburg.deUNSPECIFIED
Date:12 February 2014
Journal or Publication Title:Journal of The Electrochemical Society
Refereed publication:Yes
Open Access:No
Gold Open Access:No
In SCOPUS:Yes
In ISI Web of Science:Yes
Volume:161
DOI :10.1149/2.070404jes
Page Range:F480-F492
Publisher:Electrochemical Society, Inc.
ISSN:0013-4651
Status:Published
Keywords:Solid oxide fuel cell (SOFC), Cathode, Oxygen reduction, LSCF, elementary kinetics, modeling, simulation, validation.
HGF - Research field:Energy
HGF - Program:Efficient Energy Conversion and Use (old)
HGF - Program Themes:Fuel Cells (old)
DLR - Research area:Energy
DLR - Program:E EV - Energy process technology
DLR - Research theme (Project):E - Electrochemical Processes (old)
Location: Stuttgart
Institutes and Institutions:Institute of Engineering Thermodynamics > Computational Electrochemistry
Deposited By: Yurkiv, Vitaliy
Deposited On:09 Sep 2014 13:39
Last Modified:08 Mar 2018 18:46

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