Electrochemical and degradation behaviour study of different SOFC compounds

Abstract

The present work is focused on manufacturing processes of the solid oxide fuel cell (SOFC) components with previously self-synthesized materials by combustion method [1-2]. The configuration used consists of planar electrolyte-supported symmetric cells, with dense yttria-stabilized zirconia (YSZ) membranes about 20mm diameter and a thickness near 300μm. Ni-yttria-stabilized zirconia cermet (Ni-YSZ) [3] and La0.6Sr0.4FeO3 (LSF40) [4] layers were deposited on the surfaces of the electrolyte as anode and cathode, respectively. In order to decrease the interlayer reactivity and improve the contact between them, Ce0.8Sm0.2O1.9 (SDC), LaNi0.6Fe0.4O3 (LNF60) and MnCo1.9Fe0.1O4 (MCF10) were added in different combinations as protection barrier [5], contact layer [6] and protective layer [7] material, respectively. The deposition of the different compounds has been carried out by manual colloidal spraying, using an organic base solution, or by screen printing. Cross section SEM images have been done to study morphologically the different starting layers. In order to study the degradation of the samples after 500h of exposure time at a temperature of 800 ºC, the energy-dispersive X-ray spectroscopy analysis of the cross sectional micrographs has been evaluated. Electrochemical impedance spectroscopy was used to characterize the electrochemical properties of the different components and multilayer structures.