Disclosed is a catalyst slurry for fuel cells and a method for manufacturing the same in which two kinds of ionomers having different equivalent weights (EWs) are used such that the respective ionomers may be formed at positions suitable for maximally exhibiting the functions thereof.

Disclosed are a catalyst electrode for a fuel cell, a method for fabricating the catalyst electrode, and a fuel cell including the catalyst electrode. The presence of an ionomer-ionomer support composite in the catalyst electrode prevents the porous structure of the catalyst electrode from collapsing due to oxidation of a carbon support to avoid an increase in resistance to gas diffusion and can stably secure proton channels. The presence of carbon materials with high conductivity is effective in preventing the electrical conductivity of the electrode from deterioration resulting from the use of a metal oxide in the ionomer-ionomer support composite and is also effective in suppressing collapse of the porous structure of the electrode to prevent an increase in resistance to gas diffusion in the electrode. Based on these effects, the fuel cell exhibits excellent performance characteristics and prevents its performance from deteriorating during continuous operation.

Methods for manufacturing a catalyst layer of a membrane-electrode assembly may include preparing a solution including an ionomer and a solvent, forming a catalyst slurry composition by adding a carbon powder catalyst to the solution, forming a catalyst layer by applying the catalyst slurry composition onto a base material, and then drying the catalyst slurry composition.

A method of producing an infiltrated solid oxide fuel cell (SOFC) layer. The method begins by infiltrating a solution containing a solute into a SOFC layer to produce a primary SOFC layer. The primary SOFC layer is then dried in a heated environment, wherein the heated environment ranges in temperature from about 25° C. to about 100° C. to produce a dry primary SOFC layer. The dry primary SOFC layer is then cooled at a rate less than about 5° C./min to room temperature to produce a cooled primary SOFC layer. The cooled primary SOFC layer is then heated to a temperature greater than 500° C. then quenching to a temperature from about 10° C. to about 30° C. to produce an infiltrated SOFC layer.

A solid oxide electrochemical cell includes a solid oxide electrolyte, an anode located on a first side of the solid oxide electrolyte, and a cathode located on a second side of the solid oxide electrolyte. The cathode includes lanthanum nickel ferrite.

A catalyst layer includes an electrode catalyst and an ionomer. The electrode catalyst includes: tin oxide-based particles having a structure (connected structure) in which porous primary particles are connected to each other in a bead shape and having a specific surface area of 30 m.sup.2/g or more; and Pt-based fine particles supported on the surface of the tin oxide-based particles. The conductivity of a green compact composed of the tin oxide-based particles is desirably 1×10.sup.−3 S/cm or more. As the tin oxide-based particles, those composed of Sb-doped SnO.sub.2 and having a specific surface area of 90 m.sup.2/g or more and a pore diameter of 5 nm or more and 8 nm or less are desired.

A manufacturing process includes: depositing a catalyst support on a gas diffusion layer to form a catalyst support-coated gas diffusion layer; depositing a catalyst on the catalyst support-coated gas diffusion layer to form a catalyst-coated gas diffusion layer; and depositing an ionomer on the catalyst-coated gas diffusion layer to form an ionomer-coated gas diffusion layer. A membrane electrode assembly for a fuel cell includes: a gas diffusion layer; a polymer electrolyte membrane; and a catalyst layer disposed between the gas diffusion layer and the polymer electrolyte membrane, wherein the catalyst layer includes an ionomer, and a concentration of the ionomer varies within the catalyst layer according to a concentration profile.

A method for producing a carbon nanomaterial for use as a catalyst, including the steps of: (a) providing a precursor which is a source of lignin, (b) heating the precursor to an activation temperature from 700° C. to 800° C. in the presence of an alkali solution in order to produce an activated precursor, and (c) reacting the activated precursor with a source of nitrogen atoms in order to dope the activated precursor with nitrogen atoms, wherein the precursor is heated in step (b) to the activation temperature at a rate of at least 500° C. per minute.

Some aspects of the invention may be directed to a catalyst layer for anodes of Alkaline Exchange Membrane Fuel Cells (AEMFC). Such catalyst layer may include catalyst nanoparticles and an ionomer. Each catalyst nanoparticle may include one or more nanoparticles of catalytically active metal supported on at least one nanoparticle of crystalline RuO.sub.2. The diameter of the at least one nanoparticle of the crystalline RuO.sub.2 may be about order of magnitude larger than the diameter of the one or more nanoparticles of catalytically active metal.

A method is proposed by means of which a composite layer is producible in as simple and controlled a manner as possible, and by means of which composite layers with different predetermined properties can be produced with as little expenditure as possible, and thus economically. The method includes: providing a nanofiber material, comminuting the nanofiber material while forming nanorods, providing a liquid medium, which comprises an ionomer component and a dispersant, dispersing the nanorods in the liquid medium while forming a nanorod ionomer dispersion, and applying the nanorod ionomer dispersion to a surface region of a substrate while forming a composite layer. An electrochemical unit including the composite layer is provided. The composite layer is useful in a fuel cell (hydrogen fuel cell or direct alcohol fuel cell), in a redox flow cell, in an electrolytic cell, or in an ion exchanger, and useful for anion or proton conduction.