Investigation of ceria-molten carbonate electrolyte, composite anode and its catalytical effect on various carbon fuels in molten carbonate direct coal/carbon fuel cell

In order to improve the power density of molten carbonate direct coal/carbon fuel cell (MC-DCFC), a composite electrolyte of ceria-carbonate and ceria-coal/carbon anode are used. Electrochemical impedance spectroscopy (EIS) results reveal that ohmic resistance decreases 15-56.5 % in ceria-molten carbonate electrolyte. The surface morphology exhibit core-shell structures, which increase CO32- ionic transportation between the electrolyte surface and ceria-core particle. Among the all-carbon fuels, bituminous coal and graphite powders obtain a peak power density of 160 and 186 mW/cm(2) with a maximum current density of 850 and 924 mA/cm(2), respectively, at 700 degrees C. In contrast, the catalytical effect of CeO2 (50 wt%) is analyzed on four different carbon fuels at 600 degrees C. Incorporating ceria in graphite fuel lowers the apparent activation energy and enhances the reactivity. The EIS analysis displays the low charge transfer resistance in ceria-carbon fuel due to the indirect electrochemical redox. Ceria-graphite (>= 100 mu m) electrode achieves the highest power density of 203 mW/cm(2) with a maximum current density of 1009 mA/cm(2) for MC-DCFC at 600 degrees C. In Ceria-graphite anode indirect redox pathway works together with direct electrochemical oxidation contributing to the high-power density, resulting in the maximum power density increase by 19.1 % compared to the carbonate electrolyte.