In this work, pentavalent metal ions of Nb or Ta are doped in the Fe sites of La_0.6Sr_0.4FeO_3−δ (LSFO), and the doping effects on the redox stability and electrochemical properties of LSFO are investigated. Nb‐ or Ta‐doped LSFO is synthesized by a citric acid‐based sol–gel process and solid‐state reaction. The doping of metal ions in LSFO is confirmed by powder XRD and Rietveld refinements. The oxidation states of the doped metal ions are also confirmed by X‐ray photoelectron spectroscopy. In a stability test in a reducing atmosphere of H₂, the undoped LSFO shows structural deterioration, whereas the doping of pentavalent metal ions leads to an enhancement in the structural stability of LSFO. Electrical conductivity measurements show that the LSFO compounds with 10 mol % Nb or Ta show the highest conductivity value under conditions of air or H₂. Long‐term stability tests show that all the metal‐doped LSFO are much more stable than LSFO.

中文翻译：

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五价金属离子（Nb5 +或Ta5 +）的掺杂对La0.6Sr0.4FeO3-δ的氧化还原稳定性和电化学性能的影响，用作固体氧化物燃料电池的互连体

在这项工作中，Nb或Ta的五价金属离子被掺杂在La _0.6 Sr _0.4 FeO3 _-δ（LSFO）的Fe位置，并研究了掺杂对LSFO的氧化还原稳定性和电化学性能的影响。Nb或Ta掺杂的LSFO是通过基于柠檬酸的溶胶-凝胶工艺和固态反应合成的。粉末XRD和Rietveld精炼方法证实了LSFO中金属离子的掺杂。掺杂的金属离子的氧化态也可以通过X射线光电子能谱来确认。在H ₂还原气氛中进行稳定性测试，未掺杂的LSFO显示出结构劣化，而五价金属离子的掺杂导致LSFO的结构稳定性增强。电导率测量表明，在空气或H ₂条件下，Nb或Ta含量为10 mol％的LSFO化合物显示出最高的电导率值。长期稳定性测试表明，所有金属掺杂的LSFO都比LSFO稳定得多。