Synthesis and preliminary study of pure and Zr-doped YMnO3 compounds as Solid Oxide Fuel Cells electrode

• Y1−xZrxMnO3 (x = 0, 0.05 and 0.1) and 8YSZ show chemical compatibility after sintering.
• YMnO3 is also thermomechanically compatible with 8YSZ electrolyte in air.
• (Y,Zr)MnO3 are unstable in H2 for T > 600 °C, precluding their use for SOFC anode.

The Y1−xZrxMnO3 series (0 ≤ x ≤ 0.30) has been studied to be used as possible SOFC electrode material. These compounds adopt a layered structure of hexagonal symmetry in which the manganese cations are located in trigonal bi-pyramidal coordination of oxygen atoms, different from that of the classical perovskite. The synthesis of the materials has been carried out by solid state reaction and X-ray diffraction technique reveals that pure phases can be obtained until x∼0.10. For x ≥ 0.10, an additional YSZ phase is formed, similar to the SOFC electrolyte material. HT-XRD technique and thermogravimetric analysis of pure or Zr-doped YMnO3 indicate that, in diluted dry H2 for T > 600 °C, these compounds are unstable, what precludes their use as anode material. On the other hand, reactivity studies at high temperature (T = 1300 °C) between Y1−xZrxMnO3 (x = 0, 0.05 and 0.1) and 8YSZ show a chemical compatibility in which the formation of an electrically insulating phase does not take place, but a crossed diffusion of Y3+/Mn3+ and Zr4+ at the interface between both materials. Thermomechanical compatibility in air between YSZ and Y1−xZrxMnO3 is also demonstrated from RT to 850 °C.

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