An Ag-Coated NiO Cathode for MCFCs Operating at Low Temperatures

Abstract

To increase the lifetime of molten carbonate fuel cell (MCFC) stacks, a reduction of the operating temperature is needed without decreasing the cell performance. In this study, a Ag coating on a conventional NiO cathode material of MCFC was carried out to enhance the cathode performance at the relatively low operating temperature of 600 degrees C. Ag is a material applicable to cathodes for MCFCs because Ag has good catalytic activity for oxygen adsorption and dissociation and high electrical conductivity. The modified cathode was prepared by a vacuum suction method using a nanosized Ag sol suspension, and Ag particles were dispersed homogenously on the surface of a porous Ni plate. After the Ag coating, the cell performance was enhanced significantly from 0.76 to 0.80 V at a 150 mA/cm(2) current density at 600 degrees C. The electrochemical impedance spectra show that the reduction of the charge transfer resistance is the main reason for the improvement of the cell performance after the Ag coating. (C) 2011 The Electrochemical Society. [DOI: 10.1149/1.3571532] All rights reserved.