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Lecture

Characterization of BaCe0.4Zr0.4Y0.2O3-δ Protonic Conductor in-operando conditions

Thursday (27.09.2018)
10:30 - 10:45 S1/03 - 223
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Recently, BaCe0.4Zr0.4Y0.2O3-δ (BCZY) perovskite was proposed as PC-SOFC electrolyte due to its high bulk protonic conductivity and good CO2 tolerance. However, the operating temperature range needs to be carefully determined to be used as proton conductor electrolyte. Relationship between the electrochemical and crystallographic properties for barium cerates and zirconates is expected according to bibliography [1]. In addition, different crystal structures for compositions similar to BCZY between room temperature and 800 °C under static air have been reported [2]. In this sense, it is possible that BCZY compound presents rhombohedral or monoclinic instead of cubic symmetry. Therefore, BCZY requires a more detailed characterization as a function of temperature and atmosphere. In this work, BCZY was synthesized by solid state reaction (SSR), calcined and sintered at 1600 °C for 12 hours. Crystallographic and electrical properties were studied simultaneously by performing in-operando synchrotron X-ray diffraction (XRD) and Electrochemical Impedance Spectroscopy (EIS), respectively. These measurements were performed between room temperature and 800 °C under wet synthetic air. Homemade sample holder was designed to study electrical and structural properties under in-operando conditions. A strong correlation between crystallographic and electrochemical properties was observed. Protonic conductivity is the dominant transport mechanism below to 500 °C. Otherwise, oxygen vacancies dominate transport mechanism above 500 °C. Neutron powder diffraction (NPD) was used to determine crystallographic space group and evaluate oxygen non-stoichiometry of BCZY perovskite. XRD and NPD patterns were simultaneously refined indicating that BCZY presents rhombohedral symmetry below to 600 °C, while above this temperature it presents cubic symmetry. The correlation between crystallographic and electrochemical properties is discussed.

Speaker:
Dr.-Ing. Catalina Jiménez
Helmholtz-Zentrum Berlin für Materialien und Energie
Additional Authors:
  • Dr. Juan Basbus
    Comisión Nacional de Energía Atómica / National Scientific and Technical Research Council (CONICET)
  • Dr. Mauricio Arce
    Comisión Nacional de Energía Atómica / National Scientific and Technical Research Council (CONICET)
  • Dr. Federico Napolitano
    Comisión Nacional de Energía Atómica / National Scientific and Technical Research Council (CONICET)
  • Dr. Martin Saleta
    Comisión Nacional de Energía Atómica / National Scientific and Technical Research Council (CONICET)
  • Prof. Dr. Nikolas Bonanos
    Technical University of Denmark
  • Dr. Jose Alonso
    Instituto de Ciencia de Materiales de Madrid / Spanish National Research Council (CSIC)
  • Dr. Maria Teresa Fernández Díaz
    Institut Laue Langevin
  • Prof. Dr. Lars Giebeler
    Leibniz Institute for Solid State and Materials Research Dresden
  • Prof. Dr. Alberto Caneiro
    Comisión Nacional de Energía Atómica / National Scientific and Technical Research Council (CONICET)
  • Prof. Dr. Adriana Serquis
    Comisión Nacional de Energía Atómica / National Scientific and Technical Research Council (CONICET)
  • Prof. Dr. Liliana Mogni
    Comisión Nacional de Energía Atómica (CNEA)

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