Abstract: A method may form an electroconductive and hydrophobic microporous layer (MPL) at an active layer surface configured for an electrochemical converter, including: (a) providing a non-aqueous dispersion, called “ink”, including a carbon-based particulate material and an organic solvent; (b) forming an ink deposit at the active layer surface; and (c) evaporating the solvent(s) to form a microporous layer, simultaneously and/or subsequently to the forming (b). The ink may include poly(vinylidene fluoride-co-hexafluoropropene), dissolved in the organic solvent. Ink may prepare such a microporous layer, and a multilayer structure including an active layer supported by a solid electrolyte membrane and contacting, at its face on the opposite side the solid membrane, with a microporous layer obtained by the such a method. A membrane-electrode assembly may include such a multilayer structure. Such an MEA may be used in an individual cell of an electrochemical converter, in particular in a PEMFC.

Abstract: A process for manufacturing a gas diffusion device includes providing a superposition of a composite layer and of an electrically conductive element, the composite layer including electrically conductive fibers and a polymerizable resin impregnating the conductive fibers, and the electrically conductive element having an open porosity between a first face and a second face. The process also includes compressing the superposition of the composite layer and of the conductive element so as to bring said conductive fibers into contact with the first face of the element, so as to make said resin flow into said element without the resin impregnating all the volume of said conductive element; and polymerizing the resin.

Abstract: The present invention relates to a gas diffusion layer for a fuel cell, made of a carbon substrate grafted with at least one aromatic group having formula (II): wherein: the asterisk * designates a carbon atom with no hydrogen and no Ri group, with i=1 to 5, and covalently bonded to the carbon substrate; at least two of the R1, R2, R3, R4, and R5 groups are different from a hydrogen atom; at least two of the R1, R2, R3, R4, and R5 groups are hydrophobic groups or hydrophilic groups or a hydrophobic group and a hydrophilic group.

Abstract: A method of treating a carbon substrate, includes the successive steps of impregnating the carbon substrate with an aqueous solution containing an amorphous fluorinated copolymer of tetrafluoroethylene and of perfluoromethoxy dioxole, drying the carbon substrate at a pressure lower than the atmospheric pressure, and obtaining a carbon substrate impregnated with a fluorinated copolymer. Such a carbon substrate may be used as a gas diffusion layer in a fuel cell.

Abstract: An active layer for a proton-exchange membrane fuel cell (PEMFC) including at least two perfluorosulfonate ionomers.

Abstract: The present invention relates to a gas diffusion layer for a fuel cell, made of a carbon substrate grafted with at least one aromatic group having formula (II): wherein: the asterisk * designates a carbon atom with no hydrogen and no Ri group, with i=1 to 5, and covalently bonded to the carbon substrate; at least two of the R1, R2, R3, R4, and R5 groups are different from a hydrogen atom; at least two of the R1, R2, R3, R4, and R5 groups are hydrophobic groups or hydrophilic groups or a hydrophobic group and a hydrophilic group.

Abstract: A method of treating a carbon substrate, includes the successive steps of impregnating the carbon substrate with an aqueous solution containing an amorphous fluorinated copolymer of tetrafluoroethylene and of perfluoromethoxy dioxole, drying the carbon substrate at a pressure lower than the atmospheric pressure, and obtaining a carbon substrate impregnated with a fluorinated copolymer. Such a carbon substrate may be used as a gas diffusion layer in a fuel cell.

Abstract: A method for producing a diffusion layer of an electrochemical device, including: superimposition of multiple unidirectional webs of carbon filaments, filaments of each web positioned parallel with, and next to, one another; needle punching of the webs, breaking a proportion of the filaments such that broken portions of the filaments are tangled with other filaments of the webs; and cutting a proportion of the multiple unidirectional webs, the carbon filaments forming one electrically conducting outer surface of the diffusion layer. The needle punching is accomplished all the way through the multiple unidirectional webs, and/or through two principal opposite faces of the multiple unidirectional webs, and/or with an impact density against the multiple unidirectional webs of between approximately 100 and 300 impacts/cm2.

Abstract: An active layer for a proton-exchange membrane fuel cell (PEMFC) including at least two perfluorosulfonate ionomers.

Abstract: A cell structure for a fuel-cell battery, which allows the compromise necessary between the reduction in the non-uniformities of mechanical stress to be optimized, with the aim of obtaining a more uniform operation, and the independent accommodation with respect to the defects in planarity/thickness/alignment, while at the same time meeting the compactness constraint, comprises: a membrane/electrode assembly comprising a first electrode and a second electrode separated by a membrane; a gas diffusion layer stacked on each face of the assembly, between an electrode of the assembly and a current collector plate; and the gas diffusion layers stacked on either side of the assembly do not have the same rigidity, one of the gas diffusion layers having a Young's modulus relative to an applied stress in the direction of the thickness, greater than the Young's modulus of the other layer, in a ratio of the order of at least 100.

Abstract: A method for measuring the thermal conductivity along three directions of an anisotropic thin material includes: positioning on the surface of the material a plurality N of sensors able to measure the temperature of the material at N measuring points; generating a heat flux from a heat source positioned on a surface of the material; determining a mapping of the theoretical temperature of the material at the N measuring points of the N sensors along three directions by using a calculator, determining a mapping of the real temperature on the surface of the anisotropic material by measuring the temperature of the material at the N measuring points of N sensors; determining using the calculator the real thermal conductivity of the thin anisotropic material, along three directions, by a plurality of adjustments of the theoretical thermal conductivity by minimising the difference between the theoretical temperature and the real temperature for each of the N temperature measuring points.

Abstract: This gas diffusion layer for a PEMFC includes at least one hydrophilic electronically-conductive thread, advantageously formed of a carbon thread, of an electronically conductive hydrophilic material thread, or of a polymer thread loaded with electronically-conductive particles.

Abstract: A method for producing a diffusion layer of an electrochemical device, including: superimposition of multiple unidirectional webs of carbon filaments, filaments of each web positioned parallel with, and next to, one another; needle punching of the webs, breaking a proportion of the filaments such that broken portions of the filaments are tangled with other filaments of the webs; and cutting a proportion of the multiple unidirectional webs, the carbon filaments forming one electrically conducting outer surface of the diffusion layer. The needle punching is accomplished all the way through the multiple unidirectional webs, and/or through two principal opposite faces of the multiple unidirectional webs, and/or with an impact density against the multiple unidirectional webs of between approximately 100 and 300 impacts/cm2.