A FIB-STEM study of strontium segregation and interface formation of directly assembled La0.6Sr0.4Co0.2Fe0.8O3-δ Cathode on Y2O3-ZrO2 electrolyte of solid oxide fuel cells

Shuai He, Martin Saunders, Kongfa Chen, Haifeng Gao, Alexandra Suvorova, William D. A. Rickard, Zakaria Quadir, C. Q. Cui, San Ping Jiang

Research output: Contribution to journalArticle

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Abstract

Electrode/electrolyte interface plays a critical role in the performance and stability of solid oxide fuel cells (SOFCs). Here, interface formation, Sr segregation and reaction of directly assembled La0.6Sr0.4Co0.2Fe0.8O3.delta, (LSCF) cathode on barrier-layer-free Y2O3-ZrO2 (YSZ) electrolyte are studied at 1000 mAcm(-2) and 750 degrees C using focused ion beam and scanning transmission electron microscopy (FIB-STEM) techniques. The results indicate that polarization promotes the formation of LSCF/YSZ interface with a high level of periodicity and symmetry but no amorphous phases or solid solutions. Further polarization induces the Sr segregation and diffusion toward the LSCF/YSZ interface, forming Sr rich layer (SRL, primarily SrO) at LSCF and YSZ interface. Segregated Sr species are highly mobile and deposition of SrO occurs at the LSCF/YSZ interface as well as on the YSZ electrolyte surface. The reaction between SRL and YSZ is fast, forming SrZrO3 secondary phase. The growth of SrZrO3 phase at the interface are affected by the crystallography lattice plane orientation of the YSZ electrolyte, forming a coherence interface between SrZrO3 and YSZ electrolyte. Further polarization accelerates Sr segregation and formation of the SrZrO3 reaction layer, leading to the disintegration of LSCF structure at the interface. The results indicate that chemical reaction between LSCF and YSZ occurs at 750 degrees C under polarization conditions, kinetically induced by the segregated SrO at the interface and on the YSZ electrolyte surface. (C) 2018 The Electrochemical Society.

Original languageEnglish
Pages (from-to)F417-F429
Number of pages13
JournalJournal of the Electrochemical Society
Volume165
Issue number7
DOIs
Publication statusPublished - 20 Apr 2018

Cite this

@article{3463fa5b0a7e4138955b9b8ac1f64269,
title = "A FIB-STEM study of strontium segregation and interface formation of directly assembled La0.6Sr0.4Co0.2Fe0.8O3-δ Cathode on Y2O3-ZrO2 electrolyte of solid oxide fuel cells",
abstract = "Electrode/electrolyte interface plays a critical role in the performance and stability of solid oxide fuel cells (SOFCs). Here, interface formation, Sr segregation and reaction of directly assembled La0.6Sr0.4Co0.2Fe0.8O3.delta, (LSCF) cathode on barrier-layer-free Y2O3-ZrO2 (YSZ) electrolyte are studied at 1000 mAcm(-2) and 750 degrees C using focused ion beam and scanning transmission electron microscopy (FIB-STEM) techniques. The results indicate that polarization promotes the formation of LSCF/YSZ interface with a high level of periodicity and symmetry but no amorphous phases or solid solutions. Further polarization induces the Sr segregation and diffusion toward the LSCF/YSZ interface, forming Sr rich layer (SRL, primarily SrO) at LSCF and YSZ interface. Segregated Sr species are highly mobile and deposition of SrO occurs at the LSCF/YSZ interface as well as on the YSZ electrolyte surface. The reaction between SRL and YSZ is fast, forming SrZrO3 secondary phase. The growth of SrZrO3 phase at the interface are affected by the crystallography lattice plane orientation of the YSZ electrolyte, forming a coherence interface between SrZrO3 and YSZ electrolyte. Further polarization accelerates Sr segregation and formation of the SrZrO3 reaction layer, leading to the disintegration of LSCF structure at the interface. The results indicate that chemical reaction between LSCF and YSZ occurs at 750 degrees C under polarization conditions, kinetically induced by the segregated SrO at the interface and on the YSZ electrolyte surface. (C) 2018 The Electrochemical Society.",
keywords = "SR SURFACE SEGREGATION, COMPOSITE OXYGEN-ELECTRODE, YTTRIA-STABILIZED ZIRCONIA, 600 DEGREES-C, THIN-FILMS, PEROVSKITE-STRUCTURE, BARRIER-LAYER, ELECTROCHEMICAL PERFORMANCE, REVERSIBLE SOEC/SOFC, SDC INTERLAYER",
author = "Shuai He and Martin Saunders and Kongfa Chen and Haifeng Gao and Alexandra Suvorova and Rickard, {William D. A.} and Zakaria Quadir and Cui, {C. Q.} and Jiang, {San Ping}",
year = "2018",
month = "4",
day = "20",
doi = "10.1149/2.0151807jes",
language = "English",
volume = "165",
pages = "F417--F429",
journal = "Journal of the Electrochemical Society",
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publisher = "ELECTROCHEMICAL SOC INC",
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}

A FIB-STEM study of strontium segregation and interface formation of directly assembled La0.6Sr0.4Co0.2Fe0.8O3-δ Cathode on Y2O3-ZrO2 electrolyte of solid oxide fuel cells. / He, Shuai; Saunders, Martin; Chen, Kongfa; Gao, Haifeng; Suvorova, Alexandra; Rickard, William D. A.; Quadir, Zakaria; Cui, C. Q.; Jiang, San Ping.

In: Journal of the Electrochemical Society, Vol. 165, No. 7, 20.04.2018, p. F417-F429.

Research output: Contribution to journalArticle

TY - JOUR

T1 - A FIB-STEM study of strontium segregation and interface formation of directly assembled La0.6Sr0.4Co0.2Fe0.8O3-δ Cathode on Y2O3-ZrO2 electrolyte of solid oxide fuel cells

AU - He, Shuai

AU - Saunders, Martin

AU - Chen, Kongfa

AU - Gao, Haifeng

AU - Suvorova, Alexandra

AU - Rickard, William D. A.

AU - Quadir, Zakaria

AU - Cui, C. Q.

AU - Jiang, San Ping

PY - 2018/4/20

Y1 - 2018/4/20

N2 - Electrode/electrolyte interface plays a critical role in the performance and stability of solid oxide fuel cells (SOFCs). Here, interface formation, Sr segregation and reaction of directly assembled La0.6Sr0.4Co0.2Fe0.8O3.delta, (LSCF) cathode on barrier-layer-free Y2O3-ZrO2 (YSZ) electrolyte are studied at 1000 mAcm(-2) and 750 degrees C using focused ion beam and scanning transmission electron microscopy (FIB-STEM) techniques. The results indicate that polarization promotes the formation of LSCF/YSZ interface with a high level of periodicity and symmetry but no amorphous phases or solid solutions. Further polarization induces the Sr segregation and diffusion toward the LSCF/YSZ interface, forming Sr rich layer (SRL, primarily SrO) at LSCF and YSZ interface. Segregated Sr species are highly mobile and deposition of SrO occurs at the LSCF/YSZ interface as well as on the YSZ electrolyte surface. The reaction between SRL and YSZ is fast, forming SrZrO3 secondary phase. The growth of SrZrO3 phase at the interface are affected by the crystallography lattice plane orientation of the YSZ electrolyte, forming a coherence interface between SrZrO3 and YSZ electrolyte. Further polarization accelerates Sr segregation and formation of the SrZrO3 reaction layer, leading to the disintegration of LSCF structure at the interface. The results indicate that chemical reaction between LSCF and YSZ occurs at 750 degrees C under polarization conditions, kinetically induced by the segregated SrO at the interface and on the YSZ electrolyte surface. (C) 2018 The Electrochemical Society.

AB - Electrode/electrolyte interface plays a critical role in the performance and stability of solid oxide fuel cells (SOFCs). Here, interface formation, Sr segregation and reaction of directly assembled La0.6Sr0.4Co0.2Fe0.8O3.delta, (LSCF) cathode on barrier-layer-free Y2O3-ZrO2 (YSZ) electrolyte are studied at 1000 mAcm(-2) and 750 degrees C using focused ion beam and scanning transmission electron microscopy (FIB-STEM) techniques. The results indicate that polarization promotes the formation of LSCF/YSZ interface with a high level of periodicity and symmetry but no amorphous phases or solid solutions. Further polarization induces the Sr segregation and diffusion toward the LSCF/YSZ interface, forming Sr rich layer (SRL, primarily SrO) at LSCF and YSZ interface. Segregated Sr species are highly mobile and deposition of SrO occurs at the LSCF/YSZ interface as well as on the YSZ electrolyte surface. The reaction between SRL and YSZ is fast, forming SrZrO3 secondary phase. The growth of SrZrO3 phase at the interface are affected by the crystallography lattice plane orientation of the YSZ electrolyte, forming a coherence interface between SrZrO3 and YSZ electrolyte. Further polarization accelerates Sr segregation and formation of the SrZrO3 reaction layer, leading to the disintegration of LSCF structure at the interface. The results indicate that chemical reaction between LSCF and YSZ occurs at 750 degrees C under polarization conditions, kinetically induced by the segregated SrO at the interface and on the YSZ electrolyte surface. (C) 2018 The Electrochemical Society.

KW - SR SURFACE SEGREGATION

KW - COMPOSITE OXYGEN-ELECTRODE

KW - YTTRIA-STABILIZED ZIRCONIA

KW - 600 DEGREES-C

KW - THIN-FILMS

KW - PEROVSKITE-STRUCTURE

KW - BARRIER-LAYER

KW - ELECTROCHEMICAL PERFORMANCE

KW - REVERSIBLE SOEC/SOFC

KW - SDC INTERLAYER

U2 - 10.1149/2.0151807jes

DO - 10.1149/2.0151807jes

M3 - Article

VL - 165

SP - F417-F429

JO - Journal of the Electrochemical Society

JF - Journal of the Electrochemical Society

SN - 0013-4651

IS - 7

ER -