An electrode structure of a flow battery. A density of the vertical tow in the electrode fiber is larger than the density of the parallel tow. In the electrode fiber per unit volume, the quantity ratio of the vertical tow to the parallel tow is at least 6:4. The electrode structure includes an odd number of layers of the electrode fibers, and the porosity of other layers is larger than that of the center layer. The electrode structure includes the vertical tows, so that, the contact area between the outer surface of the electrode and the adjacent component is increased and the contact resistance is reduced; the electrode has good mechanical properties; the contact resistance of such structure is reduced by 30%-50%; and the layers of the electrode have different thickness depending on the porosity. After compression, the layers with optimized thickness have a consistent porosity.

A monolithic electrode structure for use in electrochemical flow cells is presented. The monolithic electrode structure includes a dense region with embedded flow channels that provides functionality of a flow field layer and a porous region that provides combined functionalities of gas diffusion and catalyst layers. The monolithic electrode structure is additively fabricated to include regions of different porosities/densities. A material of the monolithic electrode structure is a pure metal that is a catalyst for a targeted electrochemical reaction, or an alloy that contains such pure metal. Porosity of the porous region is adjusted to allow flow of liquid, such as water, towards or away from an active surface of the electrode. According to one aspect, porosity is adjusted by adjusting the pore size that make the porous region. According to another aspect, the dense region contains cooling channels for cooling of the electrode.

Methods for optimizing, designing, making, and assembling various component parts and layers to produce optimized MEAs. Optimization is generally achieved by producing multi-layered MEAs wherein characteristics such as catalyst composition and morphology, ionomer concentration, and hydrophobicity/hydophilicity are specifically tuned in each layer. The MEAs are optimized for use with a variety of catalysts including catalysts with specifically designed and controlled morphology, chemical speciation on the bulk, chemical speciation on the surface, and/or specific hydrophobic or hydrophilic or other characteristics. The catalyst can incorporate non-platinum group metal (non-PGM) and/or platinum group metal (PGM) materials.

A cathode configured to use oxygen as a cathode active material includes: a porous film including a metal oxide, where a porosity of the porous film is about 50 volume percent to about 95 volume percent, based on a total volume of the porous film, and an amount of an organic component in the porous film is 0 to about 2 weight percent, based on a total weight of the porous film.

A fuel cell with high productivity, high power generation performance and high durability is described, along with a gas diffusion electrode base material having a microporous layer on one side of an electrically conductive porous base material, where the electrically conductive porous base material contains carbon fiber and resin carbide and has a density of 0.25 to 0.39 g/cm.sup.3 and a pore mode diameter in a range of 30 to 50 μm. The microporous layer contains a carbonaceous powder and a fluororesin and has a surface roughness of 2.0 to 6.0 μm, a porosity of 50 to 95%, and a pore mode diameter of 0.050 to 0.100 μm.

A membrane catalyst layer assembly includes: a PEM; and a pair of catalyst layers disposed on main surfaces of the PEM. One of the pair of catalyst layers contains: mesoporous carbon with an average particle size of 100 nm or more, the mesoporous carbon having mesopores with a mode radius of 1-25 nm and a pore volume of 1.0-3.0 cm.sup.3/g; a catalytic metal; a proton-conducting resin; and at least one type of carbon particles with a smaller average particle size than the mesoporous carbon. The one of the pair of catalyst layers has a first surface layer which is adjacent to the PEM and contains the mesoporous carbon, and a second surface layer which is opposite the PEM and contains the mesoporous carbon, a volume percentage of the mesoporous carbon in the second surface layer is lower than a volume percentage of the mesoporous carbon in the first surface layer.

Disclosed are a carbon substrate for a gas diffusion layer of a fuel cell, a gas diffusion layer employing the same, an electrode for a fuel cell, a membrane electrode assembly for a fuel cell, and a fuel cell, wherein the carbon substrate includes a plate-shaped substrate having an upper surface and a lower surface opposite the upper surface, and the plate-shaped substrate includes carbon fibers arranged to extend in one direction (extend unidirectionally) and a carbide of an organic polymer located between the carbon fibers to bind the carbon fibers to each other. Since the carbon substrate according to the present disclosure includes carbon fibers aligned in at least one direction selected from a machine direction (MD) and a cross-machine direction (CMD) by controlling the alignment of carbon fibers, the carbon substrate has excellent mechanical strength, particularly, bending strength, even if its thickness is thin, and thus it is possible to effectively prevent the intrusion phenomenon of the gas diffusion layer into the flow path of the metal separator, and has excellent gas flow characteristics.

An electrode material (1) for a fuel cell (50), comprising a planar body (11) made of an electrically conductive foam having an open and continuous porosity for at least one operating medium of the fuel cell (50), wherein the planar body (11) has a top side (12) and a bottom side (13), and wherein the thickness (14) of the material across all points (12a, 12a′) on the surface of the top side (12), measured in each case between a point (12a, 12a′) on the surface of the top side (12) and the point (13a, 13a′) opposite this point (12a, 12a′) on the surface of the bottom side (13), varies by at least 10%. An electrode (2) for a fuel cell (50), comprising a planar body (21) made of an electrically conductive foam having an open and continuous porosity for at least one operating medium of the fuel cell (50), wherein the planar body (21) has a top side (22) and a bottom side (23), and wherein the top side (22), and/or the bottom side (23), has regions (22a, 23a) in which the porosity of the planar body (11) is reduced by at least 10%. A fuel cell (50) comprising the electrode (2). A method for production.

There is described a direct carbon fuel cell system. The system includes fuel cells, each fuel cell having a porous fuel cell anode and a fuel cell cathode. The system further includes a molten carbonate electrolyte and a fuel supply apparatus for flowing a fuel slurry having carbon particles and a carbon carrier fluid to the fuel cell anodes in parallel. The carbon carrier fluid has a same composition as the molten carbonate electrolyte. An oxidant supply apparatus flows an oxygen-containing stream to the fuel cell cathodes in parallel. An electrolyte circulation apparatus circulates the molten carbonate electrolyte in contact with each of the fuel cells. During operation of the direct carbon fuel cell system to generate electric power, carbon is oxidized at the fuel cell anodes to produce carbon dioxide, and at the fuel cell cathodes oxygen and carbon dioxide react to produce carbonate ions.

Provided is a fluid-permeable electrode having an open-cell structure and having: a layer of an electroactive material deposited on a surface of an open cell substrate that is formed of a material that differs from the electroactive material; or a fluid-permeable electrode having an open-cell structure and consisting of an electroactive material.