Abstract: A method is provided for making a hydrophilic carbon fiber construction, such as a fuel cell gas diffusion layer or diffuser/current collector, by electrophoretic deposition of a metal oxide selected from Type I or Type II, where Type I consists of metal oxides having a negative zeta potential and Type II consists of metal oxides having a positive zeta potential. A hydrophilic carbon fiber construction is provided, such as a fuel cell gas diffusion layer or diffuser/current collector, which is coated with a metal oxide and capable of wicking 200 mg of water per 40 mg of the hydrophilic carbon fiber construction.

Abstract: An aqueous coating composition is provided comprising carbon particles, one or more highly fluorinated polymers and one or more amine oxide surfactants, typically an amine oxide surfactant according to formula I: 1

Abstract: A method is provided for making a hydrophilic carbon fiber construction comprising the steps of: a) immersing a carbon fiber construction in an aqueous dispersion of one or more metal oxides, comprising: i) 1-15% by weight metal oxide; ii) 0.01%-5% by weight dispersant; and b) subsequently heating the carbon fiber construction sufficiently to remove substantially all of the dispersant. Typically the entire method can be completed in less than 20 minutes. In addition, a hydrophilic carbon fiber construction made according to the method of the present invention is provided, typically having a loading of metal oxide equivalent to 20-50 mg metal per gram of carbon.

Abstract: An aqueous coating composition is provided comprising carbon particles, one or more highly fluorinated polymers and one or more amine oxide surfactants, typically an amine oxide surfactant according to formula I: where n is 9 to 19. The coating composition is advantageously used in a method of making a gas diffusion layer for an electrochemical cell comprising the steps of: a) coating a electrically conductive porous substrate with the aqueous coating composition, and b) heating the electrically conductive porous substrate to a temperature sufficient to decompose the amine oxide surfactants. In another aspect, a gas diffusion layer for an electrochemical cell is provided which is advantageously free of surfactant.

Abstract: An aqueous coating composition is provided comprising carbon particles, one or more highly fluorinated polymers and one or more amine oxide surfactants, typically an amine oxide surfactant according to formula I: 1

Abstract: A method is provided for making a hydrophilic carbon fiber construction, such as a fuel cell gas diffusion layer or diffuser/current collector, by electrophoretic deposition of a metal oxide selected from Type I or Type II, where Type I consists of metal oxides having a negative zeta potential and Type II consists of metal oxides having a positive zeta potential. A hydrophilic carbon fiber construction is provided, such as a fuel cell gas diffusion layer or diffuser/current collector, which is coated with a metal oxide and capable of wicking 200 mg of water per 40 mg of the hydrophilic carbon fiber construction.

Abstract: A method is provided for making a hydrophobic carbon fiber construction, such as a fuel cell gas diffusion layer, by electrophoretic deposition of a highly fluorinated polymer, which may be followed by sintering of the fluoropolymer. A hydrophobic carbon fiber construction is provided, such as a fuel cell gas diffusion layer, which is coated with a monolayer of particles of a highly fluorinated polymer, which may be sintered.

Abstract: A method is provided for making a hydrophilic carbon fiber construction comprising the steps of: a) immersing a carbon fiber construction in an aqueous dispersion of one or more metal oxides, comprising: i) 1-15% by weight metal oxide; ii) 0.01%-5% by weight dispersant; and b) subsequently heating the carbon fiber construction sufficiently to remove substantially all of the dispersant. Typically the entire method can be completed in less than 20 minutes. In addition, a hydrophilic carbon fiber construction made according to the method of the present invention is provided, typically having a loading of metal oxide equivalent to 20-50 mg metal per gram of carbon.

Abstract: A method is provided for making a gas diffusion layer for an electrochemical cell comprising the steps of: a) combining carbon particles and one or more surfactants in a typically aqueous vehicle to make a preliminary composition, typically by high shear mixing; b) adding one or more highly fluorinated polymers to said preliminary composition by low shear mixing to make a coating composition; and c) applying the coating composition to an electrically conductive porous substrate, typically by a low shear coating method.