Hydroxide electrolyte direct carbon fuel cells—Technology review

Abstract

Summary Among numerous modern high‐performance energy technologies that allow for conversion of chemical energy into electricity and heat, the most interesting are direct carbon fuel cells (DCFCs). They are the only ones among all types of fuel cells that allow for a direct conversion of chemical energy stored in the solid fuel (carbon) into electricity. Furthermore, they are characterized by high performance, which is not limited due to the Carnot's rule, low emissions of such substances as SO2, NOx, fly ashes and others, and a relatively simple design since there are no moving components. Nowadays, DCFCs have been developed all over the world. These cells differ first and foremost in the electrolyte they use. The type of electrolyte determines both configuration of the device and operating temperature. The paper discusses current state of knowledge concerning DCFC technology with alkaline (hydroxide) electrolyte and presents the results of research and development studies concerning such cells all over the world. Furthermore, main factors and parameters that impact on the operation of individual cells and potential challenges that have to be overcome in order to develop these technologies were characterized and discussed.

Recent advances in additive‐enhanced polymer electrolyte membrane properties in fuel cell applications: An overview

“…The properties of the membranes were enhanced, including good thermal stability, low water uptake, low swelling, and low methanol and conductivity. Fang employed 1,4‐diazabicyclo octane (DABCO) as the cross‐linking agent to fabricate an anion‐exchange membrane based on poly(ethylene‐co‐tetrafluoroethylene) (ETFE), which was also radiation grafted with vinyl benzyl chloride (VBC), followed by quaternization. Rao et al investigated the cross‐linking effect on the proton mobility and ion conduction of a PEM through a molecular dynamic (MD) simulation.…”

“…1 In addition, fuel cells are considered highly sustainable systems because they do not emit pollutants such as SOx, NOx, and CO 2 , the main pollutants emitted by conventional coal combustion systems. 2 However, the current limitation in fuel cell commercialization stems from the high costs of production materials and of the production process itself. 3 There are many types of fuel cells, which can be classified depending on the operative environment (eg, temperature), size and structure of the fuel cell (eg, large, moderate or mini-scale system), and the properties of the polymer electrolyte membrane in the fuel cell.…”

A steel slag–derived Boudouard reaction catalyst for improved performance of direct carbon solid oxide fuel cells

“…Novel technologies to utilize solid carbon cleanly and efficiently are urgently demanded for a sustainable energy future. Direct carbon fuel cells (DCFCs) are power generation devices that directly convert the chemical energy of solid carbon to electricity via electrochemical routines . Without the constriction of the Carnot cycle, DCFCs offer much high‐energy conversion efficiency (slightly more than 100% in theory or approximately 80% in practice), which is more than twice that obtained from conventional coal‐fired power plants .…”

“…According to the electrolyte used, DCFCs are mainly classified into three types: molten hydroxide, molten carbonate, and solid oxide DCFCs . The DCFCs with molten media as electrolyte have the advantage to ensure the intimate contact between the solid carbon fuel and the molten state electrolyte by an extended solid/liquid interface upon wetting . In the presence of CO 2 , the molten carbonate has higher stability than the molten hydroxide .…”

“…Direct carbon fuel cells (DCFCs) are power generation devices that directly convert the chemical energy of solid carbon to electricity via electrochemical routines. [1][2][3][4][5][6][7][8][9] Without the constriction of the Carnot cycle, DCFCs offer much high-energy conversion efficiency (slightly more than 100% in theory or approximately 80% in practice), which is more than twice that obtained from conventional coal-fired power plants. [3][4][5][6] Furthermore, since the gas-tight electrolyte of DCFCs just allows O 2 in the air to transport to the anode in ionic forms, the highly concentrated CO 2 product streams can be directly captured for industrial use or sequestration.…”