Abstract

ALVARADO-FLORES, J.; AVALOS-RODRIGUEZ, L.; VIRAMONTES-GAMBOA, G.  and  REYES-ROJAS, A.. Síntesis y caracterización de la doble perovskita BaSrCoFe_1-xNi_xO_5.5 como cátodo para celdas SOFC. Rev. mex. fis. [online]. 2013, vol.59, n.4, pp.309-316. ISSN 0035-001X.

Have been synthesized via sol-gel method and characterized by X-ray diffraction (XRD), electrical conductivity and thermal expansion coefficient (TEC), new material composites BaSrCoFe₁__xNi_xO₅.₅ (double perovskite type) with the addition of Ni in solid solution Ni_x (x = 0.025, 0.05, 0.075, 0.1 and 0.2), as alternative cathodes for solid oxide fuel cells of intermediate temperature (SOFC-IT). XRD confirmed the formation of the tetragonal structure perovskite phase BaSrCoFe₁__xNi_xO₅.₅ , with the presence of small peaks identified in 2θ values below 30° as BaCO₃ and CoFe₂O₄. The electrical conductivity increases with temperature between 350-470° C and then decreases due to the loss ofoxygen in the net, which causes differences in conductivity. Semiconductor behavior was obtained in all compositions. TEC determination, showed a linear dependence inversely proportional to the concentration of Ni. Our results of electrical conductivity and TEC, lead us to the conclusion that the cathodes between 0.1 and 0.2 Ni, have the greatest possibility for application in IT-SOFC.

Keywords : Composite material; sol-gel; electrical conductivity; solid oxide fuel cells (SOFC).