Nuclear Science and Techniques

《核技术》(英文版) ISSN 1001-8042 CN 31-1559/TL     2019 Impact factor 1.556

Nuclear Science and Techniques ›› 2019, Vol. 30 ›› Issue (2): 21 doi: 10.1007/s41365-019-0550-1

• NUCLEAR ENERGY SCIENCE AND ENGINEERING • Previous Articles     Next Articles

Study of the relationship between the local geometric structure and the stability of La0.6Sr0.4MnO3−δ and La0.6Sr0.4FeO3−δ electrodes

Cheng-Zhi Guan1,2 • Jing Zhou1 • Hong-Liang Bao1 • Cheng Peng1 • Xiao Lin1 • Guo-Ping Xiao1 • Jian-Qiang Wang1 • Zhi-Yuan Zhu1   

  1. 1 Department of Molten Salt Chemistry and Engineering, Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
    2 University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2018-04-08 Revised:2018-08-24 Accepted:2018-09-01
  • Contact: Jian-Qiang Wang
  • Supported by:
    This work was supported by the ‘‘The Strategic Priority Research Program’’ of the Chinese Academy of Sciences (No. XDA02040601) and the Key Project of Science and Technology of Shanghai (No. 15DZ1200100).
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Cheng-Zhi Guan, Jing Zhou, Hong-Liang Bao, Cheng Peng, Xiao Lin, Guo-Ping Xiao, Jian-Qiang Wang, Zhi-Yuan Zhu. Study of the relationship between the local geometric structure and the stability of La0.6Sr0.4MnO3−δ and La0.6Sr0.4FeO3−δ electrodes.Nuclear Science and Techniques, 2019, 30(2): 21     doi: 10.1007/s41365-019-0550-1

Abstract: Sr-substituted ABO3 perovskite oxides such as La0.6Sr0.4MnO3-d (LSM) and La0.6Sr0.4FeO3-d (LSF) are widely used as oxygen electrode materials in solid oxide cells. The substituted Sr is not adequately stable under the operating conditions, because of the surface segregation of Sr. Herein, we focused on investigating the relationship between the local geometric structure due to Sr substitution and stability of LSM and LSF. We characterized the local geometric structure of Sr atoms via X-ray absorption spectroscopy. A greater Debye–Waller factor and a longer bond length of both the second and third Sr–O shells were observed in LSF, which demonstrates that LSF has a higher local structural disorder and that Sr in LSF requires less energy to segregate. After 20 h of heat treatment in the presence of a Fe–Cr alloy interconnect, the Sr/La molar ratio on LSF was observed to be much larger than that on LSM. This result unequivocally suggests that Sr in LSF is not as stable as in LSM, and the reaction between Sr and Cr accelerates the Sr surface segregation in LSF.

Key words: Solid oxide cell, Perovskite, Strontium surface segregation, X-ray absorption spectroscopy, Chromium poisoning