Disclosed herein are gas diffusion layers (GDLs) for electrochemical devices which have increased surface area for hosting catalysts or contacting a catalyst layer. GDLs with engineered surface roughness increase the effective diffusivities of gas phase reactants in electrochemical devices (e.g., PEMFCs). Also disclosed herein are gas diffusion electrodes, membrane electrode assemblies, and fuel cells comprising GDLs with increased surface area. Also disclosed herein are methods of manufacturing GDLs with increased surface area, as well as gas diffusion electrodes and membrane electrode assemblies comprising GDLs with increased surface area.

Coatings on carbon are of interest to the battery, fuel cell, and catalyst industries. However, carbon is difficult to process because of its cohesiveness and low density. This invention describes a method for decreasing the interparticle forces between carbon particles so that the powder does not agglomerate as much during processing. This prevents the formation of hard agglomerates during gas phase processes such as Atomic Layer Deposition (ALD) coating. The same method for decreasing agglomeration of the powder during processing may also improve the dispersion of deposited platinum onto carbon particles, either by ALD or other methods. A suspension of carbon particles coated with ionomer is also described.

A fuel cell stack including a plurality of fuel cell units having a truncated cone shape and connected in series with each other is proposed. The series connection of the fuel cell units may be made such that a relatively small outer diameter portion of one of the fuel cell units is inserted into a relatively large outer diameter portion of another fuel cell unit adjacent to the one fuel cell unit.

A fuel cell stack including a plurality of fuel cell units having a truncated cone shape and connected in series with each other is proposed. The series connection of the fuel cell units may be made such that a relatively small outer diameter portion of one of the fuel cell units is inserted into a relatively large outer diameter portion of another fuel cell unit adjacent to the one fuel cell unit.

Disclosed are: a polymer electrolyte membrane which can prevent ionic conductor loss even upon the occurrence of chemical degradation in the ionic conductor according to long term use and thus can be significantly improved in chemical durability; a manufacturing method therefor; and an electrochemical device comprising same. The polymer electrolyte membrane of the present disclosure comprises a polymer electrolyte material. The polymer electrolyte material comprises an ionic conductor and a crosslinker unbound to the ionic conductor. The crosslinker has at least one cross-linkable functional group which can couple with the ionic conductor that has been degraded, thereby causing crosslinking with the ionic conductor.

Disclosed are: a polymer electrolyte membrane which can prevent ionic conductor loss even upon the occurrence of chemical degradation in the ionic conductor according to long term use and thus can be significantly improved in chemical durability; a manufacturing method therefor; and an electrochemical device comprising same. The polymer electrolyte membrane of the present disclosure comprises a polymer electrolyte material. The polymer electrolyte material comprises an ionic conductor and a crosslinker unbound to the ionic conductor. The crosslinker has at least one cross-linkable functional group which can couple with the ionic conductor that has been degraded, thereby causing crosslinking with the ionic conductor.

To provide an electrode catalyst layer, a membrane electrode assembly, and a polymer electrolyte fuel cell capable of improving the mass transport properties and proton conduction properties in the electrode catalyst layer and exhibiting high power generation performance for a longer time. An electrode catalyst layer according to an embodiment of the present invention is an electrode catalyst layer configured to be bonded to a polymer electrolyte membrane for use in a polymer electrolyte fuel cell, the electrode catalyst layer including: a catalytic substance; a conductive carrier supporting the catalytic substance; a polymer electrolyte; and one or more types of fibers containing at least a polymer fiber, wherein, among the fibers, the number of fibers having an axis inclination θ of 0°<θ<45° relative to a bonding surface between the polymer electrolyte membrane and the electrode catalyst layer is more than 50% of the total number of the contained fibers.

To provide an electrode catalyst layer, a membrane electrode assembly, and a polymer electrolyte fuel cell capable of improving the mass transport properties and proton conduction properties in the electrode catalyst layer and exhibiting high power generation performance for a longer time. An electrode catalyst layer according to an embodiment of the present invention is an electrode catalyst layer configured to be bonded to a polymer electrolyte membrane for use in a polymer electrolyte fuel cell, the electrode catalyst layer including: a catalytic substance; a conductive carrier supporting the catalytic substance; a polymer electrolyte; and one or more types of fibers containing at least a polymer fiber, wherein, among the fibers, the number of fibers having an axis inclination θ of 0°<θ<45° relative to a bonding surface between the polymer electrolyte membrane and the electrode catalyst layer is more than 50% of the total number of the contained fibers.

A method for welding between two metallic plates, including: (a) fitting a solid plate without openings, configured to be transparent at at least one emission wavelength of a laser beam (F) emitted by a laser (L), between the laser (L) and at least one contact zone between the metallic plates to be welded; (a1) inerting of the contact zone via a netural gas, where the neutral gas circulates in channels delimited by the contact zone between the metallic plates and by the solid plate; (a2) exerting pressure on the two metallic plates to apply them against one another in the contact zone to be welded, where the application pressure is exerted by the solid plate directly in contact with one of the two metallic plates to be welded; and (b) emission of a laser beam, through the solid plate, to perform welding of the metallic plates in the contact zone.

An electrode catalyst layer for fuel cells capable of effectively preventing reduction of cell voltage in a high current density region. The electrode catalyst layer contains a catalyst-on-support composed of a support made of a conductive inorganic oxide having a catalyst supported thereon and a hydrophilic material. The hydrophilic material is an agglomerate including hydrophilic conductive particles. The content of the hydrophilic material in the catalyst layer is 2 mass % or higher and lower than 20 mass % relative to the sum of the support and the hydrophilic material. The ratio of the particle size d1 of the hydrophilic particles to the particle size D of the catalyst-on-support is 0.5 to 3.0. The ratio of the particle size d2 of the hydrophilic material to the thickness T of the catalyst layer is 0.1 to 1.2.