Thermal decomposition of alkane hydrocarbons inside a porous Ni anode for fuel supply of direct carbon fuel cell: Effects of morphology and crystallinity of carbon

Intrinsic Solid-State Reaction Characteristics of Coals and Chars in a Direct Carbon Fuel Cell: With Focus on Significance Assessment of Fuel-Borne Factors

“…The electrochemical oxidation characteristics of the fuel-filled porous Ni anode were measured in a three-electrode electrochemical cell, , as shown in Figure . The cylindrical Ni anode containing the fuel was used as a working electrode (WE), after being spot-welded to a flat plate-type silver current collector (6 cm high × 0.4 cm wide).…”

“…More than 100 research articles have introduced a diversity of efforts to develop their own structures of DCFCs or to test various materials for the key system components (such as anode, cathode, and electrolyte) and fuels, in attempts to promote the system performance. It is also worth mentioning that there was a limited success in recent trials for solving the practical challenges, such as poor utilization of solid fuels − and inferior long-term operation . According to Jiang et al, promoting the carbon conversion of low-grade fuels into CO at 750 °C led to increasing the maximum power density up to ∼900 mW cm –2 , which is comparable to conventional hydrogen-fueled fuel cells.…”

“…One problem is that the electrochemical reactivity of coals is not stable but heavily dependent upon intrinsic properties, such as the reactant volatile species (H 2 , CH 4 , and CO) evolving from the coals, the contents of carbon-containing functional groups, and the specific surface area and catalytic ash components (Ca, Fe, Mg, etc.) of the coals. − In fact, it is not scarce to find conflicting results in previous studies for using coals and chars in DCFCs. The following are several examples: Ahn et al , evaluated the electrochemical characteristics of coals, biomass char, and industrial waste in a molten carbonate (MC)-based DCFC system.…”

“…When it comes to the acid or base pretreatment of coals that has recently been proposed, it will inevitably result in simultaneous changes of surface area, pore volume, surface functional groups, and catalytic ash contents of coals. Similarly, either the use of coal gasification or high-temperature operation of the DCFC cell , might be a practical method for easy fuel supply with higher reactivity , but not appropriate for a parametric study.…”

“…For these multipurposes, we prepared and used three different raw coals (and their corresponding chars) as fuel for our unique MC-based DCFC system. , Each fuel was characterized in terms of volatile species, surface functional groups, specific surface area, ash components, and resulting syngas compositions. As mentioned before, a small amount of fuel (1.0 g for each of coals or chars) was applied and tested at a low operation temperature of 600 °C.…”