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−δ (LSCF), Ba0.5Sr0.5Co0.2Fe0.8O3−δ (BSCF), La0.9Sr0.1Ga0.8Mg0.2O3−δ (LSGM), and Gd0.2Ce0.8O3−δ (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 °C. According to the results of the electrochemical test and electrochemical impedance spectroscopy (EIS), the composite cathode layer with YSZ–La0.8Sr0.2MnO3−δ (LSM) interlayer exhibits the best electrochemical performance. The maximum power density can achieve the value above 400 mW/cm2 for the samples with YSZ–LSM interlayer.