Fabrication and evaluation of electrochemical characteristics of the composite cathode layers for the anode-supported solid-oxide fuel cells

The various composite cathode layers on the solid oxide fuel cells (SOFCs) with a dense electrolyte of yttria-stabilized zirconia (YSZ) are investigated in this study. The ceramic powders of La0.6Sr0.4Co0.2Fe0.8O3-delta (LSCF), Ba0.5Sr0.5Co0.2Fe0.8O3-delta (BSCF), La0.9Sr0.1Ga0.8Mg0.2O3-delta (LSGM), and Gd0.2Ce0.8O3-delta (GDC) are prepared by the glycine-nitrate combustion process. The different formations of composite cathode layers are coated onto the NiO-YSZ/YSZ half-cells via a screen printing method. Scanning electron microscopy (SEM) micrographs show that all of the samples can be well adherent to the YSZ electrolyte. From the energy dispersive X-ray (EDX) result, the undesired compound of SrZrO3 is formed between the YSZ electrolyte and the composite cathode layers with LSCF and BSCF at the sintering temperature of 1000 degrees C. According to the results of the electrochemical test and electrochemical impedance spectroscopy (EIS), the composite cathode layer with YSZ-La0.8Sr0.2MnO3-delta (LSM) interlayer exhibits the best electrochemical performance. The maximum power density can achieve the value above 400 mW/cm(2) for the samples with YSZ LSM interlayer. (C) 2011 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.