Preparation and Characterization of La0.4Sr0.6Co0.8Fe0.2O3 Films

L. BAQUÉ; A. SERQUIS; M.S. MORENO; N. GRUNBAUM; A. CANEIRO

Puerto Madryn, Chubut

Congreso; II Reunión de la Asociación Argentina de Cristalografía; 2006

The cobaltites La1−xSrxCo1-yFeyO3-δ (LSCF) are good candidates for solid oxide fuel cell (SOFC) cathodes because these materials present high ionic and electronic conductivity, allowing a lower temperature of operation [1,2]. Most of reported LSFC films have been synthesized by slurry deposition techniques such as spraying [3], painting [4], or spin coating [5,6]. In order to increase SOFCs performances further, it is necessary to understand how the microstructure of the composites electrodes affects the performance of the system. The aim of this work is to study the microstructure and electrode resistance of porous electrodes of the same composition films (La0.4Sr0.6Co0.8Fe0.2O3-d) deposited by different methods and to identify the sintering conditions to obtain low cathode overpotential values. The influence of the microstructure on the transport properties (ionic and electronic conductivity) is evaluated by means of impedance spectroscopy. The perovskite oxide cobaltites powders have been prepared by an acetic acid-based gel and HTMA routes. Then, cathodes films were deposited onto ceramic substrates of the usual electrolytes Cerium Gadolinium Oxide (CGO), by serigraphy, spin coating and dip-coating. The structure, morphology and composition of the powders and films were characterized by XRD, SEM, and EDS, respectively. The grain size and strain of initial powders and films prepared through different routes is analyzed by Rietveld analysis. We found that the electrochemical properties of LSFC cathodes films strongly depend on the microstructure that is mainly determined by synthesis parameters and technique used for the deposition of the films.