1. Design of Sr0.7R0.3CoO3-δ(R = Tb and Er) Perovskites Performing as Cathode Materials in Solid Oxide Fuel Cells
- Author
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Vanessa Cascos, J. A. Alonso, Ainara Aguadero, George F. Harrington, and M. T. Fernández-Díaz
- Subjects
Technology ,Materials science ,0306 Physical Chemistry (Incl. Structural) ,ENERGY-CONVERSION ,Materials Science ,Analytical chemistry ,Oxide ,chemistry.chemical_element ,02 engineering and technology ,Electrolyte ,010402 general chemistry ,Electrochemistry ,01 natural sciences ,Oxygen ,TRANSPORT-PROPERTIES ,chemistry.chemical_compound ,Tetragonal crystal system ,Materials Science, Coatings & Films ,Materials Chemistry ,COBALT ,0912 Materials Engineering ,Polarization (electrochemistry) ,Science & Technology ,Energy ,Renewable Energy, Sustainability and the Environment ,Atmospheric temperature range ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,0104 chemical sciences ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Secondary ion mass spectrometry ,chemistry ,SR0.7HO0.3COO3-DELTA ,Physical Sciences ,MIXED-CONDUCTING OXIDES ,OXYGEN DIFFUSION ,0210 nano-technology ,SIMS ,SYSTEM ,0303 Macromolecular And Materials Chemistry - Abstract
Sr0.7R0.3CoO3-δ (R = Tb and Er) tetragonal perovskites have been prepared and evaluated as mixed ionic-electronic cathodes for SOFC. Neutron powder diffraction (NPD) measurements evidenced that both compounds are oxygen hypo-stoichiometric with long-range order of oxygen vacancies that leads to a tetragonal perovskite-type superstructure (s.g. I4/mmm) stable within the whole temperature range under study. The oxygen vacancies located mainly in the equatorial oxygen positions exhibit large displacement factors. The high oxygen mobility in Sr0.7Tb0.3CoO3-δ was confirmed by 18O oxygen labeling followed by Secondary Ion Mass Spectrometry (SIMS) with values of oxygen self-diffusion of 1.29 × 10−10 cm2/s at 525°C. Polarization resistances with LSGM as electrolyte gave values as low as 0.011 Ω⋅cm2 and maximum output powers of 570 mW/cm2 at 850°C were obtained in test cells set in electrolyte-supported configuration. Electrical conductivity, thermal and chemical expansion and stability measurements confirm the potential of these materials as cathodes for SOFC.
- Published
- 2017
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