Effect of high-temperature ageing on (La,Sr)(Co,Fe)O3-δ cathodes in microtubular solid oxide fuel cells

Hongqian Wang; Hirofumi Sumi; Scott A. Barnett

doi:10.1016/j.ssi.2018.05.019

Effect of high-temperature ageing on (La,Sr)(Co,Fe)O_3-δ cathodes in microtubular solid oxide fuel cells

Hongqian Wang, Hirofumi Sumi, Scott A. Barnett^*

^*Corresponding author for this work

Materials Science and Engineering

Research output: Contribution to journal › Article › peer-review

16 Scopus citations

Abstract

Microtubular solid oxide fuel cells with La_0.6Sr_0.4Co_0.2Fe_0.8O_3-δ (LSCF) cathodes were aged in ambient air at temperatures ranging from 700 to 1000 °C for up to 700 h. Distribution of relaxation time analysis of electrochemical impedance spectroscopy (EIS) measurements indicated an increase in the cathode resistance with increasing ageing temperature up to 900 °C. The cells aged at 1000 °C were not measurable. The degradation did not result from microstructural changes, as shown by focused ion beam-scanning electron microscopy (FIB-SEM) 3D tomography that showed no significant changes at ageing temperatures ≤900 °C. On the other hand, the amount of segregated Sr, present both on LSCF surfaces and in Sr-rich particles, increased with increasing ageing temperature and correlated well with the increase in cathode resistance. Analysis of the EIS and microstructural data using the Alder-Lane-Steele model indicates that the Sr surface segregation increases cathode resistance via a decreased oxygen surface exchange rate.

Original language	English (US)
Pages (from-to)	85-91
Number of pages	7
Journal	Solid State Ionics
Volume	323
DOIs	https://doi.org/10.1016/j.ssi.2018.05.019
State	Published - Oct 1 2018

Keywords

AC impedance
Distribution of relaxation time (DRT)
Focused ion beam-scanning electron microscopy (FIB-SEM)
Perovskite cathode
Solid oxide fuel cell (SOFC)

ASJC Scopus subject areas

Chemistry(all)
Materials Science(all)
Condensed Matter Physics

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10.1016/j.ssi.2018.05.019

Cite this

@article{69a6d9fb0aa44bc28e222d3a94841077,

title = "Effect of high-temperature ageing on (La,Sr)(Co,Fe)O3-δ cathodes in microtubular solid oxide fuel cells",

abstract = "Microtubular solid oxide fuel cells with La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) cathodes were aged in ambient air at temperatures ranging from 700 to 1000 °C for up to 700 h. Distribution of relaxation time analysis of electrochemical impedance spectroscopy (EIS) measurements indicated an increase in the cathode resistance with increasing ageing temperature up to 900 °C. The cells aged at 1000 °C were not measurable. The degradation did not result from microstructural changes, as shown by focused ion beam-scanning electron microscopy (FIB-SEM) 3D tomography that showed no significant changes at ageing temperatures ≤900 °C. On the other hand, the amount of segregated Sr, present both on LSCF surfaces and in Sr-rich particles, increased with increasing ageing temperature and correlated well with the increase in cathode resistance. Analysis of the EIS and microstructural data using the Alder-Lane-Steele model indicates that the Sr surface segregation increases cathode resistance via a decreased oxygen surface exchange rate.",

keywords = "AC impedance, Distribution of relaxation time (DRT), Focused ion beam-scanning electron microscopy (FIB-SEM), Perovskite cathode, Solid oxide fuel cell (SOFC)",

author = "Hongqian Wang and Hirofumi Sumi and Barnett, {Scott A.}",

note = "Funding Information: Special thanks to Dr. J{\"u}rgen Fleig and Dr. Ghislain M. Rupp for development of the chemical etching method for measuring Sr surface segregation. The work was supported in part by Minister of Economy, Trade and Industry, under the Japan–U.S. Cooperation Project for Research and Standardization of Clean Energy Technologies. The authors at Northwestern gratefully acknowledge financial support from the National Science Foundation under grant Number DMR-1506925. The FIB-SEM tomography data was collected at the Electron Probe Instrumentation Center (EPIC) at the NUANCE Center-Northwestern University, which has received support from the MRSEC program (NSF DMR-1121262) at the Materials Research Center; the International Institute for Nanotechnology (IIN); and the State of Illinois, through the IIN. Publisher Copyright: {\textcopyright} 2018 Elsevier B.V.",

year = "2018",

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doi = "10.1016/j.ssi.2018.05.019",

language = "English (US)",

volume = "323",

pages = "85--91",

journal = "Solid State Ionics",

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TY - JOUR

T1 - Effect of high-temperature ageing on (La,Sr)(Co,Fe)O3-δ cathodes in microtubular solid oxide fuel cells

AU - Wang, Hongqian

AU - Sumi, Hirofumi

AU - Barnett, Scott A.

N1 - Funding Information: Special thanks to Dr. Jürgen Fleig and Dr. Ghislain M. Rupp for development of the chemical etching method for measuring Sr surface segregation. The work was supported in part by Minister of Economy, Trade and Industry, under the Japan–U.S. Cooperation Project for Research and Standardization of Clean Energy Technologies. The authors at Northwestern gratefully acknowledge financial support from the National Science Foundation under grant Number DMR-1506925. The FIB-SEM tomography data was collected at the Electron Probe Instrumentation Center (EPIC) at the NUANCE Center-Northwestern University, which has received support from the MRSEC program (NSF DMR-1121262) at the Materials Research Center; the International Institute for Nanotechnology (IIN); and the State of Illinois, through the IIN. Publisher Copyright: © 2018 Elsevier B.V.

PY - 2018/10/1

Y1 - 2018/10/1

N2 - Microtubular solid oxide fuel cells with La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) cathodes were aged in ambient air at temperatures ranging from 700 to 1000 °C for up to 700 h. Distribution of relaxation time analysis of electrochemical impedance spectroscopy (EIS) measurements indicated an increase in the cathode resistance with increasing ageing temperature up to 900 °C. The cells aged at 1000 °C were not measurable. The degradation did not result from microstructural changes, as shown by focused ion beam-scanning electron microscopy (FIB-SEM) 3D tomography that showed no significant changes at ageing temperatures ≤900 °C. On the other hand, the amount of segregated Sr, present both on LSCF surfaces and in Sr-rich particles, increased with increasing ageing temperature and correlated well with the increase in cathode resistance. Analysis of the EIS and microstructural data using the Alder-Lane-Steele model indicates that the Sr surface segregation increases cathode resistance via a decreased oxygen surface exchange rate.

AB - Microtubular solid oxide fuel cells with La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) cathodes were aged in ambient air at temperatures ranging from 700 to 1000 °C for up to 700 h. Distribution of relaxation time analysis of electrochemical impedance spectroscopy (EIS) measurements indicated an increase in the cathode resistance with increasing ageing temperature up to 900 °C. The cells aged at 1000 °C were not measurable. The degradation did not result from microstructural changes, as shown by focused ion beam-scanning electron microscopy (FIB-SEM) 3D tomography that showed no significant changes at ageing temperatures ≤900 °C. On the other hand, the amount of segregated Sr, present both on LSCF surfaces and in Sr-rich particles, increased with increasing ageing temperature and correlated well with the increase in cathode resistance. Analysis of the EIS and microstructural data using the Alder-Lane-Steele model indicates that the Sr surface segregation increases cathode resistance via a decreased oxygen surface exchange rate.

KW - AC impedance

KW - Distribution of relaxation time (DRT)

KW - Focused ion beam-scanning electron microscopy (FIB-SEM)

KW - Perovskite cathode

KW - Solid oxide fuel cell (SOFC)

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