Microbial fuel cells capable of generating energy from an organic-based fuel are described. The microbial fuel cells can include an anode component, a cathode component, and a separator component selected to reduce spacing between the anode and the cathode thereby improving performance of the microbial fuel cell. Cathode components including particular components that improve the lifetime, performance, and production of the cathode component at reduced cost also are described, as well as a method of using the microbial fuel cells.

A microporous layer for use in a fuel cell includes a first carbon black having carboxyl groups at a concentration less than 0.1 mmol per gram of carbon, a hydrophobic additive and a hydrophilic additive. A method for producing a membrane electrode assembly includes preparing a microporous layer ink, applying the microporous layer ink to a first side of a gas diffusion substrate, sintering the gas diffusion substrate to form a gas diffusion layer having a first side with a microporous layer, and thermally bonding the first side of the gas diffusion layer to an electrode layer. The microporous layer ink includes a suspension medium, a first carbon black having carboxyl groups at a concentration less than 0.1 mmol per gram of carbon, a hydrophobic additive and a hydrophilic additive.

This disclosure provides a manufacturing method for manufacturing a fuel cell separator. The manufacturing method includes: providing a material sheet including a fiber sheet, carbon particles, and a resin, the carbon particles and the resin being applied to the fiber sheet; and pressing the material sheet into a recess-projection shape by which a gas circulation passage is to be formed, and forming a top portion and a shift portion. In the pressing of the material sheet, the material sheet is pressed such that a draft of the top portion is higher than a draft of the shift portion.

This disclosure provides a manufacturing method for manufacturing a fuel cell separator. The manufacturing method includes: providing a material sheet including a fiber sheet, carbon particles, and a resin, the carbon particles and the resin being applied to the fiber sheet; and pressing the material sheet into a recess-projection shape by which a gas circulation passage is to be formed, and forming a top portion and a shift portion. In the pressing of the material sheet, the material sheet is pressed such that a draft of the top portion is higher than a draft of the shift portion.

In order to provide a membrane electrode assembly that can further improve power generation performances of a fuel cell, the present invention allows a rib portion (22) that separates mutually adjacent gas flow passages (21) from each other to have a porosity lower than the porosity of a lower area (23) of the rib portion. Thus, it is possible to suppress the deformation of the rib portion and excessive permeation of a reaction gas, and consequently to further improve the power generation performances.

In order to provide a membrane electrode assembly that can further improve power generation performances of a fuel cell, the present invention allows a rib portion (22) that separates mutually adjacent gas flow passages (21) from each other to have a porosity lower than the porosity of a lower area (23) of the rib portion. Thus, it is possible to suppress the deformation of the rib portion and excessive permeation of a reaction gas, and consequently to further improve the power generation performances.

A gas diffusion layer (30) for a fuel cell includes: a gas diffusion layer substrate (31); and a microporous layer (32) containing a granular carbon material and scale-like graphite and formed on the gas diffusion layer substrate (31). The microporous layer (32) includes a concentrated region (32a) of the scale-like graphite that is formed into a belt-like shape extending in a direction approximately parallel to a junction surface (31a) between the microporous layer (32) and the gas diffusion layer substrate (31). Accordingly, both resistance to dry-out and resistance to flooding, which are generally in a trade-off relationship, in the gas diffusion layer can be ensured so as to contribute to an increase in performance of a polymer electrolyte fuel cell.

A gas diffusion layer (30) for a fuel cell includes: a gas diffusion layer substrate (31); and a microporous layer (32) containing a granular carbon material and scale-like graphite and formed on the gas diffusion layer substrate (31). The microporous layer (32) includes a concentrated region (32a) of the scale-like graphite that is formed into a belt-like shape extending in a direction approximately parallel to a junction surface (31a) between the microporous layer (32) and the gas diffusion layer substrate (31). Accordingly, both resistance to dry-out and resistance to flooding, which are generally in a trade-off relationship, in the gas diffusion layer can be ensured so as to contribute to an increase in performance of a polymer electrolyte fuel cell.

A fuel cell gas supply and diffusion layer includes a sheet-like porous body layer, and a plurality of gas passage grooves formed on one surface of the porous body layer in parallel and formed in a zigzag shape or a wave shape respectively. As viewed in a plan view, a first rectangular region where circumscribes one gas passage groove and a second rectangular region where circumscribes a gas passage groove adjacent to the one gas passage groove overlap along a region in contact each other. An overlapping region where the first rectangular region and the second rectangular region overlap exists at any depth position of the grooves. According to the fuel cell gas supply and diffusion layer, it is possible to increase a power generation efficiency of a fuel cell.

A fuel cell gas supply and diffusion layer includes a sheet-like porous body layer, and a plurality of gas passage grooves formed on one surface of the porous body layer in parallel and formed in a zigzag shape or a wave shape respectively. As viewed in a plan view, a first rectangular region where circumscribes one gas passage groove and a second rectangular region where circumscribes a gas passage groove adjacent to the one gas passage groove overlap along a region in contact each other. An overlapping region where the first rectangular region and the second rectangular region overlap exists at any depth position of the grooves. According to the fuel cell gas supply and diffusion layer, it is possible to increase a power generation efficiency of a fuel cell.