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Title: Lattice Expansion of LSCF-6428 Cathodes Measured by In-situ XRD during SOFC Operation

Abstract

A new capability has been developed for analyzing solid oxide fuel cells (SOFCs). This paper describes the initial results of in-situ x-ray diffraction (XRD) of the cathode on an operating anode-supported solid oxide fuel cell. It has been demonstrated that XRD measurements of the cathode can be performed simultaneously with electrochemical measurements of cell performance or electrochemical impedance spectroscopy (EIS). While improvements to the technique are still to be made, the XRD pattern of a lanthanum strontium cobalt ferrite (LSCF) cathode with the composition La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF-6428) was found to continually but gradually change over the course of more than 60 hours of operation in air under typical SOFC operating conditions. It was determined that the most significant change was a gradual increase in the cubic lattice parameters of the LSCF from 3.92502 Å (as determined from the integration of the first 20 hours of XRD patterns) to 3.92650 Å (from the integration of the last 20 hours). This analysis also revealed that there were several peaks from unidentified minor phases that increased in intensity over this timeframe. After a temporary loss of airflow early in the test, the cell generated between 225 and 250 mW/cm2 for the remainder of themore » test. A large low frequency arc in the impedance spectra suggests the cell performance was gas diffusion limited and that there is room for improvement in air delivery to the cell.« less

Authors:
; ; ; ;
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1033449
Report Number(s):
PNNL-SA-82491
Journal ID: ISSN 0378-7753; JPSODZ; AA2530000; TRN: US201202%%761
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Journal Name:
Journal of Power Sources, 198:76-82
Additional Journal Information:
Journal Volume: 198; Journal ID: ISSN 0378-7753
Country of Publication:
United States
Language:
English
Subject:
30 DIRECT ENERGY CONVERSION; AIR; CATHODES; COBALT; CUBIC LATTICES; DIFFUSION; FERRITE; IMPEDANCE; LANTHANUM; PERFORMANCE; SOLID OXIDE FUEL CELLS; SPECTRA; SPECTROSCOPY; STRONTIUM; X-RAY DIFFRACTION; SOFC; In-situ XRD; LSCF; Cathode; Segregation; Lattice Strain

Citation Formats

Hardy, John S, Templeton, Jared W, Edwards, Danny J, Lu, Zigui, and Stevenson, Jeffry W. Lattice Expansion of LSCF-6428 Cathodes Measured by In-situ XRD during SOFC Operation. United States: N. p., 2012. Web. doi:10.1016/j.jpowsour.2011.09.099.
Hardy, John S, Templeton, Jared W, Edwards, Danny J, Lu, Zigui, & Stevenson, Jeffry W. Lattice Expansion of LSCF-6428 Cathodes Measured by In-situ XRD during SOFC Operation. United States. https://doi.org/10.1016/j.jpowsour.2011.09.099
Hardy, John S, Templeton, Jared W, Edwards, Danny J, Lu, Zigui, and Stevenson, Jeffry W. 2012. "Lattice Expansion of LSCF-6428 Cathodes Measured by In-situ XRD during SOFC Operation". United States. https://doi.org/10.1016/j.jpowsour.2011.09.099.
@article{osti_1033449,
title = {Lattice Expansion of LSCF-6428 Cathodes Measured by In-situ XRD during SOFC Operation},
author = {Hardy, John S and Templeton, Jared W and Edwards, Danny J and Lu, Zigui and Stevenson, Jeffry W},
abstractNote = {A new capability has been developed for analyzing solid oxide fuel cells (SOFCs). This paper describes the initial results of in-situ x-ray diffraction (XRD) of the cathode on an operating anode-supported solid oxide fuel cell. It has been demonstrated that XRD measurements of the cathode can be performed simultaneously with electrochemical measurements of cell performance or electrochemical impedance spectroscopy (EIS). While improvements to the technique are still to be made, the XRD pattern of a lanthanum strontium cobalt ferrite (LSCF) cathode with the composition La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF-6428) was found to continually but gradually change over the course of more than 60 hours of operation in air under typical SOFC operating conditions. It was determined that the most significant change was a gradual increase in the cubic lattice parameters of the LSCF from 3.92502 Å (as determined from the integration of the first 20 hours of XRD patterns) to 3.92650 Å (from the integration of the last 20 hours). This analysis also revealed that there were several peaks from unidentified minor phases that increased in intensity over this timeframe. After a temporary loss of airflow early in the test, the cell generated between 225 and 250 mW/cm2 for the remainder of the test. A large low frequency arc in the impedance spectra suggests the cell performance was gas diffusion limited and that there is room for improvement in air delivery to the cell.},
doi = {10.1016/j.jpowsour.2011.09.099},
url = {https://www.osti.gov/biblio/1033449}, journal = {Journal of Power Sources, 198:76-82},
issn = {0378-7753},
number = ,
volume = 198,
place = {United States},
year = {Tue Jan 03 00:00:00 EST 2012},
month = {Tue Jan 03 00:00:00 EST 2012}
}