Abstract:
The present invention relates to a compressed mass of expanded graphite particles in the form of aflexible graphite sheet (10). The flexible graphite sheet is formed from particles of expanded natural graphite formed from graphite flake sized no more than about 30 % by weight + 80 mesh prior to expansion. The flexible graphite sheet (10) is provided with channels (20) which are perferably smooth-sided as indicated at (67) in Figure 5 and which pass between the opposite surfaces (30) and (40) of flexible graphite sheet (10) and are separated by walls (3) of compressed expandable graphite. The channels preferably have openings (50) on one of the opposed surfaces (30) which are larger than the openings (60) in the other opposed surface (40).
Abstract:
A method of manufacturing material suitable for the construction of a component of a fuel cell, such as a flow field plate or electrode, is provided. Uncured resin impregnated flexible graphite sheet is ground into particles. Without re-expanding the particles, and without adding further resin to the particles, the particles are molded into the form of the desired material. The material is then cured. Additives may be mixed with the particles to improve the properties of the material.
Abstract:
Methods are provided for manufacturing bipolar graphite articles (110). First and second components (112, 114) are formed from flexible graphite material. The first component (112) may have a protrusion (122) formed thereon, and the second component (114) may have a recess (128) formed therein which is complementary to the protrusion (122) of the first component (112). The first and second components (112, 114) are assembled so that the protrusion (122) of the first component (112) is received in the recess (128) of the second component (114). Preferably, the components are made from uncured resin impregnated graphite material. The assembled components are then pressed together and heated to cure the resin so as to bond the components together. Alternatively the second component (114), or both the components, may have flat surfaces which engage the other component.
Abstract:
A method of manufacturing an electrode for an electrochemical fuel cell is disclosed, comprising providing a sheet (10) of compressed mass of expanded graphite particles having a plurality of perforations (20) defined by walls of the expanded graphite particles, and the perforations passing through the sheet between first and second opposed surfaces of the sheet; coating the sheet with a thermosettable organic resin (66), said coating step comprising filling a portion of said perforations with the thermosettable organic resin; curing and baking the sheet, and reopening a portion of the filled perforations during the curing and baking step; activating the thermosettable organic resin to form a high surface area carbon on the walls of the perforations; and loading a catalyst (600) onto the high surface area carbon.
Abstract:
An improved method enables preparation of articles for a variety of applications, including embossing or otherwise shaping to form a variety of articles. A plurality of thin, preferably resin-impregnated, flexible graphite sheets 12 and 14 are arranged to form zones in a composite material 10 having a graded density or other characteristic. Variation of properties between zones in the stock material formed is useful for achieving a desired set of properties in the formation of articles such as those useful in electrochemical fuel cells and double-layer capacitors.
Abstract:
The invention presented is a graphite article having predetermined anisotropic characteristics, as well as a process for preparing the article. More particularly, the article is prepared by a process involving determining the desired anisotropic characteristics for a finished flexible graphite article (FIg. 1a); intercalating and then exfoliating flakes of graphite to form exfoliated graphite particles; forming a substrate graphite article by compressing the exfoliated graphite particles into a coherent article formed of graphene layers; and producing a controlled directional alignment of the graphene layers in the substrate graphite article to provide a finished graphite article having the desired anisotropic ratio. The article may be embossed and the relative amount of structure in an embossed flexible graphite wall can and will lead to differing anisotropic properites. The embossing apparatus (10) comprises two opposed elements (20) and (30).
Abstract:
Methods are provided for manufacturing bipolar graphite articles. First and second components (112 and 114) are formed from flexible graphite material. The first component (112) may have a protrusion (122) formed thereon, and the second component (114) may have a recess (128) formed therein which is complementary to the protrusion (122) of the first component (112). The first and second components (112 and 114) are assembled so that the protrusion (122) of the first component (112) is received in the recess (128) of the second component (114). Preferably, the components are made from uncured resin impregnated graphite material. The assembled components are then pressed together and heated to cure the resin so as to bond the components together. Alternatively the second component, or both the components, may have flat surfaces which engage the other component.
Abstract:
A method for producing a material useful for forming a component for an electrochemical fuel cell is provided. More particularly, the component is formed of a sheet (10) of a compressed mass of expanded graphite particles. The component is treated with a water resistant additive sufficient to provide utility as a component in an electrochemical fuel cell. Preferably, the water resistant additive is a fluoropolymer material. More preferably, the water resistant additive is a polytetrafluoroethylene material. The treatment preferably occurs by coating and/or impregnating the water resistant material in the sheet of graphite particles.
Abstract:
A method enables preparation of a stock or starting material having improved catalytic properties. These materials will be useful in the formation of articles adapted for use in electrochemical fuel cells.
Abstract:
A method enables preparation of a stock or starting material having improved thermal and/or electrical properties along with a desired set of other properties. These materials will be useful in the formation of articles adapted for use in electrochemical fuel cells and supercapacitors.