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Title: Functionally Graded Cathodes for Solid Oxide Fuel Cells

Abstract

One primary suspected cause of long-term performance degradation of solid oxide fuels (SOFCs) is the accumulation of chromium (Cr) species at or near the cathode/electrolyte interface due to reactive Cr molecules originating from Cr-containing components (such as the interconnect) in fuel cell stacks. To date, considerable efforts have been devoted to the characterization of cathodes exposed to Cr sources; however, little progress has been made because a detailed understanding of the chemistry and electrochemistry relevant to the Cr-poisoning processes is still lacking. This project applied multiple characterization methods - including various Raman spectroscopic techniques and various electrochemical performance measurement techniques - to elucidate and quantify the effect of Cr-related electrochemical degradation at the cathode/electrolyte interface. Using Raman microspectroscopy the identity and location of Cr contaminants (SrCrO{sub 4}, (Mn/Cr){sub 3}O{sub 4} spinel) have been observed in situ on an LSM cathode. These Cr contaminants were shown to form chemically (in the absence of current flowing through the cell) at temperatures as low as 625 C. While SrCrO{sub 4} and (Mn/Cr){sub 3}O{sub 4} spinel must preferentially form on LSM, since the LSM supplies the Sr and Mn cations necessary for these compounds, LSM was also shown to be an active site formore » the deposition of Ag{sub 2}CrO{sub 4} for samples that also contained silver. In contrast, Pt and YSZ do not appear to be active for formation of Cr-containing phases. The work presented here supports the theory that Cr contamination is predominantly chemically-driven and that in order to minimize the effect, cathode materials should be chosen that are free of cations/elements that could preferentially react with chromium, including silver, strontium, and manganese.« less

Authors:
;
Publication Date:
Research Org.:
Georgia Inst. of Technology, Atlanta, GA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
920188
DOE Contract Number:  
FC26-05NT42515
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
30 DIRECT ENERGY CONVERSION; CATHODES; CATIONS; CHEMISTRY; CHROMIUM; CONTAMINATION; DEPOSITION; ELECTROCHEMISTRY; FUEL CELLS; MANGANESE; OXIDES; PERFORMANCE; SILVER; SOLID OXIDE FUEL CELLS; SPINELS; STRONTIUM

Citation Formats

Abernathy, Harry, and Liu, Meilin. Functionally Graded Cathodes for Solid Oxide Fuel Cells. United States: N. p., 2006. Web. doi:10.2172/920188.
Abernathy, Harry, & Liu, Meilin. Functionally Graded Cathodes for Solid Oxide Fuel Cells. United States. https://doi.org/10.2172/920188
Abernathy, Harry, and Liu, Meilin. Sun . "Functionally Graded Cathodes for Solid Oxide Fuel Cells". United States. https://doi.org/10.2172/920188. https://www.osti.gov/servlets/purl/920188.
@article{osti_920188,
title = {Functionally Graded Cathodes for Solid Oxide Fuel Cells},
author = {Abernathy, Harry and Liu, Meilin},
abstractNote = {One primary suspected cause of long-term performance degradation of solid oxide fuels (SOFCs) is the accumulation of chromium (Cr) species at or near the cathode/electrolyte interface due to reactive Cr molecules originating from Cr-containing components (such as the interconnect) in fuel cell stacks. To date, considerable efforts have been devoted to the characterization of cathodes exposed to Cr sources; however, little progress has been made because a detailed understanding of the chemistry and electrochemistry relevant to the Cr-poisoning processes is still lacking. This project applied multiple characterization methods - including various Raman spectroscopic techniques and various electrochemical performance measurement techniques - to elucidate and quantify the effect of Cr-related electrochemical degradation at the cathode/electrolyte interface. Using Raman microspectroscopy the identity and location of Cr contaminants (SrCrO{sub 4}, (Mn/Cr){sub 3}O{sub 4} spinel) have been observed in situ on an LSM cathode. These Cr contaminants were shown to form chemically (in the absence of current flowing through the cell) at temperatures as low as 625 C. While SrCrO{sub 4} and (Mn/Cr){sub 3}O{sub 4} spinel must preferentially form on LSM, since the LSM supplies the Sr and Mn cations necessary for these compounds, LSM was also shown to be an active site for the deposition of Ag{sub 2}CrO{sub 4} for samples that also contained silver. In contrast, Pt and YSZ do not appear to be active for formation of Cr-containing phases. The work presented here supports the theory that Cr contamination is predominantly chemically-driven and that in order to minimize the effect, cathode materials should be chosen that are free of cations/elements that could preferentially react with chromium, including silver, strontium, and manganese.},
doi = {10.2172/920188},
url = {https://www.osti.gov/biblio/920188}, journal = {},
number = ,
volume = ,
place = {United States},
year = {2006},
month = {12}
}