| Autor: |
Muñoz Gil D; Instituto de Cerámica y Vidrio, CSIC, Cantoblanco, 28049 Madrid, Spain., Boulahya K; Departamento de Química Inorgánica, Facultad Ciencias Químicas, Universidad Complutense, E-28040 Madrid, Spain., Santamaria Santoyo M; Departamento de Química Inorgánica, Facultad Ciencias Químicas, Universidad Complutense, E-28040 Madrid, Spain., Azcondo MT; Facultad de Farmacia, Departamento de Química y Bioquímica, Urbanización Montepríncipe, Universidad San Pablo-CEU, CEU Universities, Boadilla del Monte, E-28668 Madrid, Spain., Amador U; Facultad de Farmacia, Departamento de Química y Bioquímica, Urbanización Montepríncipe, Universidad San Pablo-CEU, CEU Universities, Boadilla del Monte, E-28668 Madrid, Spain. |
| Abstrakt: |
The effects of the contents of iron and cobalt on the crystal structure, oxygen content, thermal expansion coefficient, and electrical-electrochemical properties of materials Eu 2 SrCo x Fe 2- x O 7-δ ( x = 0.50 and 1.00) are reported. These oxides are well-ordered new members of the Ruddlesden-Popper series (Eu,Sr) n +1 (Co,Fe) n O 3 n +1 system with n = 2 as determined by selected area electron diffraction and high-resolution transmission electron microscopy and X-ray diffraction studies. The two materials are semiconductors of p-type, with much higher total conductivity under working conditions for the low cobalt compound, Eu 2 SrCo 0.50 Fe 1.50 O 7-δ . Composite cathodes prepared with this oxide present much lower area-specific resistance values (0.08 Ω·cm 2 at 973 K in air) than composites containing Eu 2 SrCo 1.00 Fe 1.00 O 7-δ (1.15 Ω·cm 2 ). This significant difference is related to the much higher total conductivity and a sufficiently high content of oxygen vacancies in the Fe-rich phase. The excellent electrochemical performance of Eu 2 SrCo 0.50 Fe 1.50 O 7-δ with low cobalt content, which shows one of the lowest area-specific resistance reported so far for a Ruddlesden-Popper oxide, makes it a good candidate for application as a cathode material for solid oxide fuel cells at intermediate temperatures in real devices. |
