Insight into surface segregation and chromium deposition on La 0.6Sr0.4Co0.2Fe0.8O 3-δ cathodes of solid oxide fuel cells

Zhao, Ling, Drennan, John, Kong, Chun, Amarasinghe, Sudath and Jiang, San Ping (2014) Insight into surface segregation and chromium deposition on La 0.6Sr0.4Co0.2Fe0.8O 3-δ cathodes of solid oxide fuel cells. Journal of Materials Chemistry A, 2 29: 11114-11123. doi:10.1039/c4ta01426j

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Author Zhao, Ling
Drennan, John
Kong, Chun
Amarasinghe, Sudath
Jiang, San Ping
Title Insight into surface segregation and chromium deposition on La 0.6Sr0.4Co0.2Fe0.8O 3-δ cathodes of solid oxide fuel cells
Formatted title
 Insight into surface segregation and chromium deposition on La0.6Sr0.4Co0.2Fe0.8O3-δ cathodes of solid oxide fuel cells
Journal name Journal of Materials Chemistry A   Check publisher's open access policy
ISSN 2050-7496
2050-7488
Publication date 2014-08-07
Year available 2014
Sub-type Article (original research)
DOI 10.1039/c4ta01426j
Open Access Status Not Open Access
Volume 2
Issue 29
Start page 11114
End page 11123
Total pages 10
Place of publication Cambridge, United Kingdom
Publisher R S C Publications
Language eng
Subject 1600 Chemistry
2105 Renewable Energy, Sustainability and the Environment
2500 Materials Science
Abstract LaSrCoFeO , (LSCF) perovskite oxide is one of the most important cathode materials in the development of intermediate temperature solid oxide fuel cells (IT-SOFCs), but vulnerable to chromium deposition and poisoning in the presence of gaseous chromium species from the chromia-forming metallic interconnect. Despite extensive studies on Cr deposition on SOFC cathode materials, there is a lack of direct evidence on the surface chemistry and Cr deposition. Here, the fundamental relationship between the surface segregation and Cr deposition of LSCF cathodes is studied on dense LSCF bar samples using a dual beam high resolution focused ion beam (FIB) and a high resolution scanning electron microscope coupled with EDS. FIB-EDS mapping results clearly indicate the segregation of SrO and CoO particles on the LSCF surface after annealing at 800 °C for 96 h. Cr deposition occurs preferentially on the segregated SrO but not on CoO. The fundamental reason for the selective and preferential Cr deposition on the segregated SrO is the exclusion effect of the presence of SrO on the reactivity between gaseous Cr species and segregated CoO, inhibiting the Cr deposition on the segregated CoO particles.
Formatted abstract
La0.6Sr0.4Co0.2Fe0.8O 3-δ, (LSCF) perovskite oxide is one of the most important cathode materials in the development of intermediate temperature solid oxide fuel cells (IT-SOFCs), but vulnerable to chromium deposition and poisoning in the presence of gaseous chromium species from the chromia-forming metallic interconnect. Despite extensive studies on Cr deposition on SOFC cathode materials, there is a lack of direct evidence on the surface chemistry and Cr deposition. Here, the fundamental relationship between the surface segregation and Cr deposition of LSCF cathodes is studied on dense LSCF bar samples using a dual beam high resolution focused ion beam (FIB) and a high resolution scanning electron microscope coupled with EDS. FIB-EDS mapping results clearly indicate the segregation of SrO and Co3O4 particles on the LSCF surface after annealing at 800 °C for 96 h. Cr deposition occurs preferentially on the segregated SrO but not on Co3O4. The fundamental reason for the selective and preferential Cr deposition on the segregated SrO is the exclusion effect of the presence of SrO on the reactivity between gaseous Cr species and segregated Co3O4, inhibiting the Cr deposition on the segregated Co3O4 particles.
Keyword Solid oxide fuel cell
Cathode materials
Perovskite oxide
Chromium deposition
Q-Index Code C1
Q-Index Status Confirmed Code
Grant ID LP110200281
Institutional Status UQ

 
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