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Prediction of secondary-phase formation and degradation in solid oxide fuel cell anodes

Neidhardt, Jonathan and Yurkiv, Vitaliy and Bessler, Wolfgang G. (2013) Prediction of secondary-phase formation and degradation in solid oxide fuel cell anodes. EnMat II - 2nd International Conference on Materials for Energy, 12.-16.05.2013, Karlsruhe, Germany.

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Abstract

Insufficient lifetime is a major factor impeding the large-scale commercialization of solid oxide fuel cell (SOFC) technology. The formation of secondary phases in the porous electrodes can occur via various chemical mechanisms and represents a major cause of degradation due to pore clogging and deactivation of active surfaces. We present a modeling and simulation study of secondary-phase formation in porous Ni/YSZ-based anodes. Specifically, we investigate the formation of solid nickel oxide (reoxidation) in the case of high fuel utilization or low cell voltages, as well as the formation of solid carbon (coking) in the case of external and internal reforming. The model is based on a multi-phase framework that allows the introduction of arbitrary solid phases (here: Ni, YSZ, NiO, Carbon) plus the gas phase. Reactions between the bulk phases are modeled via interface-adsorbed species and they are described by an elementary kinetic approach. Published experimental data are used for parameterization and validation. The dynamic model is applied to predict and analyze nickel oxidation and carbon formation in one and two dimensions as function of operating condition and cell design. Simulations show that nickel oxidation can cause a hysteretic behavior in the current/voltage behavior. Carbon deposition occurring at open circuit under reformate fuel operation can lead to a continuous decrease in open-circuit voltage. Critical operating conditions are identified and discussed.

Item URL in elib:https://elib.dlr.de/84932/
Document Type:Conference or Workshop Item (Speech)
Title:Prediction of secondary-phase formation and degradation in solid oxide fuel cell anodes
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Neidhardt, JonathanJonathan.Neidhardt (at) dlr.deUNSPECIFIED
Yurkiv, Vitaliyvitaliy.yurkiv (at) dlr.deUNSPECIFIED
Bessler, Wolfgang G.HS OffenburgUNSPECIFIED
Date:2013
Refereed publication:Yes
Open Access:Yes
Gold Open Access:No
In SCOPUS:No
In ISI Web of Science:No
Status:Published
Keywords:SOFC, degradation
Event Title:EnMat II - 2nd International Conference on Materials for Energy
Event Location:Karlsruhe, Germany
Event Type:international Conference
Event Dates:12.-16.05.2013
Organizer:Dechema e.V.
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 - Elektrochemische Prozesse (old)
Location: Stuttgart
Institutes and Institutions:Institute of Engineering Thermodynamics > Computational Electrochemistry
Deposited By: Neidhardt, Jonathan
Deposited On:04 Nov 2013 12:54
Last Modified:31 Jul 2019 19:42

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