Abstract / Full Text

In this work, effects of molybdenum doping on the crystal structure, stability, electrical conductivity, oxygen permeability and thermomechanical properties of Sr(Fe,Al)O3–δ-based perovskites, were studied. The electrochemical performance of model anodes of solid oxide fuel cells (SOFCs), made of SrFe0.7Mo0.3O3–δ, was assessed. Whilst the introduction of Mo cations improves structural stability with respect to the oxygen vacancy ordering processes, excessive molybdenum content leads to a worse phase and mechanical stability under oxidizing conditions. Mo-doping was shown to decrease the thermal and chemical expansivity, to reduce p-type electronic conductivity and to increase n-type electronic conduction. The oxygen permeation fluxes through gas-tight Sr0.97Fe0.75Al0.2Mo0.05O3–δ membranes are determined by both the bulk oxygen diffusion and surface exchange kinetics. The role of the latter factor increases on decreasing temperature and reducing oxygen partial pressure. Due to a relatively high electrical conductivity and moderate thermal expansion coefficients in reducing conditions, SrFe0.7Mo0.3O3–δ-based anodes show a substantially high electrochemical activity.

Author information
  • Institute of Solid State Physics, Russian Academy of Sciences, Chernogolovka, Moscow oblast, 142432, Russia

    V. A. Kolotygin, E. V. Tsipis & V. V. Kharton

  • Centre for Mechanical Technology and Automation, Mechanical Engineering Department, University of Aveiro, 3810-193, Aveiro, Portugal

    E. V. Tsipis & A. L. Shaula

  • Institute of Solid State Chemistry, Ural branch, Russian Academy of Sciences, Yekaterinburg, 620990, Russia

    A. A. Markov & M. V. Patrakeev

  • Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa, 2695-066, Bobadela LRS, Portugal

    J. C. Waerenborgh

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