Title: The Electrochemical Properties of Sr(Ti,Fe)O3-δ for Anodes in Solid Oxide Fuel Cells
Language: English
Authors: Nenning, Andreas 
Volgger, Lukas 
Miller, Elizabeth 
Mogni, Liliana 
Barnett, Scott 
Fleig, Jürgen  
Category: Original Research Article
Keywords: anode; defect chemistry; electrochemistry; impedance; mixed conductor; SOFC; solid oxide fuel cell; thin film; triple-phase boundary
Issue Date: 2017
Journal: Journal of the Electrochemical Society
Abstract: 
Reduction-stable mixed ionic and electronic conductors such as Sr(Ti,Fe)O3-δ (STF) are promising materials for application in anodes of solid oxide fuel cells. The defect chemistry of STF and its properties as solid oxide fuel cell (SOFC) cathode have been studied thoroughly, while mechanistic investigations of its electrochemical properties as SOFC anode material are still scarce. In this study, thin film model electrodes of STF with 30% and 70% Fe content were investigated in H2+H2O atmosphere by electrochemical impedance spectroscopy. Lithographically patterned thin film Pt current collectors were applied on top or beneath the STF thin films to compensate for the low electronic conductivity under reducing conditions. Oxygen exchange resistances, electronic and ionic conductivities and chemical capacitances were quantified and discussed in a defect chemical model. Increasing Fe content increases the electro-catalytic activity of the STF surface as well as the electronic and ionic conductivity. Current collectors on top also increase the electrochemical activity due to a highly active Pt-atmosphere-STF triple phase boundary. Furthermore, the electrochemical activity depends decisively on the H2:H2O mixing ratio and the polarization. Fe0 nanoparticles may evolve on the surface in hydrogen rich atmospheres and increase the hydrogen adsorption rate.
DOI: 10.1149/2.1271704jes
Library ID: AC15557363
URN: urn:nbn:at:at-ubtuw:3-8239
ISSN: 1945-7111
Organisation: E164 - Institut für Chemische Technologien und Analytik 
Publication Type: Article
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