State-of-the-Art La0.6Sr0.4Co0.2Fe0.8O3-δ Cathode for SOFC: Microstructural and Electrochemical Properties

Abstract

The present study concerns the influence of the cathode film thickness on the Area Specific Polarization Resistance (ASRpol ) of La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) cathode material. The cathodes consist of double layer films of LSCF deposited sequentially by Electrostatic Spray Deposition (ESD) technique as cathode functional layer (CFL) and by screen printing (SP) technique as current collecting layer (CCL). The thickness of CFL is varied from 0.5 to 18 μm by controlling the time of ESD deposition. The thickness of CCL is varied from 20 to 50 μm by SP. The results are discussed in terms of microstructure, adherence at the electrode/electrolyte interface and current constriction effects. It is found that the optimized films require at least 5-µm thick CFL and 30-µm thick CCL. In this geometry, the lowest value measured at 600 °C is 0.065 Ω cm2, which is amongst the lowest values achieved for SOFC cathodes.