Insights into the CO2 Stability-Performance Trade-Off of Antimony-Doped SrFeO3-δ Perovskite Cathode for Solid Oxide Fuel Cells

Yuqing Meng, Le Sun, Jun Gao, Wenzhou Tan, Chusheng Chen, Jianxin Yi*, Henny J.M. Bouwmeester, Zhihu Sun, Kyle S. Brinkman

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

6 Citations (Scopus)

Abstract

One major challenge for the further development of solid oxide fuel cells is obtaining high-performance cathode materials with sufficient stability against reactions with CO2 present in the ambient atmosphere. However, the enhanced stability is often achieved by using material systems exhibiting decreased performance metrics. The phenomena underlying the performance and stability trade-off has not been well understood. This paper uses antimony-doped SrFeO3-δ as a model material to shed light on the relationship between the structure, stability, and performance of perovskite-structured oxides which are commonly used as cathode materials. X-ray absorption revealed that partial substitution of Fe by Sb leads to a series of changes in the local environment of the iron atom, such as a decrease in the iron oxidation state and increase in the oxygen coordination number. Theoretical calculations show that the structural changes are associated with an increase in both the oxygen vacancy formation energy and metal-oxygen bond energy. The area-specific resistance (ASR) of the perovskite oxide increases with Sb doping, indicating a deterioration of the oxygen reduction activity. Exposure of the materials to CO2 leads to depressed oxygen desorption and an increased ASR, which becomes less pronounced at higher Sb doping levels. Origin of the stability-performance trade-off is discussed based on the structural parameters.

Original languageEnglish
Pages (from-to)11498-11506
Number of pages9
JournalACS Applied Materials and Interfaces
Volume11
Issue number12
DOIs
Publication statusPublished - 27 Mar 2019

Keywords

  • Cathode
  • CO tolerance
  • ORR
  • Solid oxide fuel cells
  • XAFS
  • CO2 tolerance
  • solid oxide fuel cells
  • cathode

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