Preparation and characterisation of Solid Oxide Fuel Cells (SOFC) cathodes films

LAURA BAQUÉ; ADRIANA SERQUIS; NICOLÁS GRUNBAUM

Buenos Aires

Workshop; Workshop: ''Recent developments in Complex Materials: Production and Characterisation''; 2005

Departamento de Física - Facultad de Ciencias Exactas - Universidad Nacional de Buenos Aires

Solid Oxide Fuel Cells (SOFC) have been extensively studied due to their possible wide range of applicability (from 1 kW up to few hundreds of kW). The principle of operation of this kind of fuel cells involves reduction of O2 in the cathode and the diffusion of oxygen ions (O2-). SOFC must work at temperature greater than 650 ºC to enable the O2- diffusion. Nevertheless, it is still necessary to investigate new materials that improve the SOFC performance and cost. Perovskite oxide mixed conductors (La, Sr)MO3-d (M= transition metal) are good candidates for SOFC cathodes because these materials present high ionic and electronic conductivity. Therefore, this type of cathodes was widely investigated in recent years. We present a study of microstructural characteristics of cathode films deposited through several techniques. (La, Sr)MO3-d (M= transition metal) compounds with 0,05 < x < 0,5 are prepared by the acetate reaction method. Then, cathodes are deposited onto usual electrolytes like Cerium Gadolinium Oxide (CGO) and Yttria Stabilized Zirconia (YSZ) substrates by serigraphy, spin coating and dip-coating. Structural characterization is made by X-ray diffraction XRD and scanning electron microscopy (SEM). Electrical properties are characterized by techniques such as electrical conductivity and complex impedance measurements. Finally, the relation between structural characteristics and electrical properties is discussed.