화학공학소재연구정보센터
Solid State Ionics, Vol.176, No.1-2, 25-31, 2005
Functionally graded cathodes fabricated by sol-gel/slurry coating for honeycomb SOFCs
Functionally graded cathodes for honeycomb solid oxide fuel cells are prepared using sol-gel/slurry coating techniques. The compositions of the cathodes are gradually changed from a material that is active for oxygen reduction and more compatible with the electrolyte (e.g., LSM for YSZ) to another material that is more conductive for current collection. The microstructure and electrochemical properties of the electrodes are systematically characterized using electron microscopy and electrochemical impedance spectroscopy. The cathodic interfacial polarization resistances for a graded cathode fired at 900 degreesC are 0.21 and 0.10 Omega cm(2) at 700 and 800 degreesC, respectively. The impedance spectra indicate that at least two separate processes contribute to the overall polarization resistances. The effects of cathode fabrication temperature and oxygen partial pressure on the high- and low-frequency impedance responses are studied in detail. (C) 2004 Elsevier B.V. All rights reserved.