The synergistic catalyst-carbonates effect on the direct bituminous coal fuel cell performance

Abstract

The current work explores the feasibility to improve the performance of a Direct Carbon Fuel Cell (DCFC): CO 2 + bituminous coal|Co-CeO 2 /YSZ/Ag|Air by infusing a gasification catalyst (Co/CeO 2) and/or Li-K carbonates mixture into the carbon fuel. The different fuel feedstock mixtures were characterized by various methods, involving chemical composition and proximate analysis, particle size distribution (PSD), X-ray diffraction (XRD), N 2 adsorption-desorption (BET method), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM), to gain insight into the effect of catalyst and/or carbonates addition to fuel mixture physicochemical characteristics. An increase of the power output up to ca. 20 and 80% is achieved for carbon/catalyst and carbon/catalyst/carbonates mixtures, respectively, in comparison to bare carbon at 700 o C, demonstrating the pronounced effect of catalyst as well as its potential synergy with carbonates. It was also shown that the achieved maximum power density is directly associated with the CO formation rate, implying the importance of in situ formed CO on the electrochemical performance. The obtained findings are further discussed based also on the corresponding AC impedance spectroscopy studies, which revealed the beneficial effect of fuel feedstock additives (catalyst and/or carbonates) on ohmic and electrode polarization resistances. The present results clearly revealed the feasibility to improve the DCFC performance by concurrently infusing a gasification catalyst and carbonates mixture into fuel feedstock.

Molten Metals and Molten Carbonates in Solid Oxide Direct Carbon Fuel Cell Anode Chamber: Liquid Metal Anode and Hybrid Direct Carbon Fuel Cells

“…As previously reported, in some works comparing HDCFCs and SO-DCFCs, the order of reactivity of different carbons was the same [77,102]. The increase in the power density was correlated with the increase in porosity and structure disorder.…”

“…Ag, Ni, Co, Ag 2 O, Fe 2 O 3 , and CaO were the most used materials to catalyze the Boudouard reaction in SO-DCFCs. The addition of a catalyst to the carbon/carbonate fuel in HDCFCs was reported in some works [64,86,102]. The addition of 50 wt% Ni drastically improved the OCV, and in the full temperature range (550-900 • C), the MPD of the HDCFC was higher than that of the cell fueled with catalyst-free carbon [64].…”

“…The addition of silver-based catalysts to the carbon/carbonate slurry enhanced the performance of the HDCFC in the order Ag < Ag 2 CO 3 < Ag 2 O [86]. Kaklidis et al [102] compared the performance of SO-DCFCs and HDCFCs, having the same cell structure, the only difference being the fuel composition, pure carbon, carbon/catalyst, carbon/carbonate, and catalyst/carbon/carbonate. A 20 wt% Co/CeO 2 catalyst was added to BiC fuel.…”

Review of molten carbonate-based direct carbon fuel cells

“…Other reactions besides the Boudouard reaction are possible, such as partial oxidation of carbon, as shown in Eqs. ( 7) and ( 8) [106].…”