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 language | English |
|---|---|
| Pages (from-to) | F417-F429 |
| Number of pages | 13 |
| Journal | Journal of the Electrochemical Society |
| Volume | 165 |
| Issue number | 7 |
| DOIs | |
| Publication status | Published - 20 Apr 2018 |
Cite this
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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 journal › Article
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 -