摘要:
A process for preparing a polymer comprising sulfonating a perfluorocyclobutane polymer with a sulfonating agent to form a sulfonated perfluorocyclobutane polymer, wherein the sulfonating agent comprises oleum or SO3 is provided. A process for preparing proton exchange membranes and fuel cells comprising the proton exchange membrane are also provided.
摘要:
A process for preparing a polymer comprising sulfonating a perfluorocyclobutane polymer with a sulfonating agent to form a sulfonated perfluorocyclobutane polymer, wherein the sulfonating agent comprises oleum, SO3 or a combination thereof is provided. A process for preparing proton exchange membranes and fuel cells comprising the proton exchange membrane are also provided.
摘要:
A process for preparing a polymer comprising sulfonating a perfluorocyclobutane polymer with a sulfonating agent to form a sulfonated perfluorocyclobutane polymer, wherein the sulfonating agent comprises oleum, SO3 or a combination thereof is provided. A process for preparing proton exchange membranes and fuel cells comprising the proton exchange membrane are also provided.
摘要:
A gas diffusion media and method of making are provided including the formation of a carbon fiber paper which is heated to a carbonization temperature without exceeding a graphitization temperature. The discovery that a final high temperature heat treatment step in the graphitization temperature zone is not necessary to make effective gas diffusion media for PEM fuel cells greatly reduces the cost associated with the high temperature final heat treatment and also allows for the processing of the diffusion media in a roll.
摘要:
A porous diffusion media according to the present invention is positioned against a catalyst layer of the membrane electrode assembly, the porous matrix comprises carbon paper, and the water transfer particles comprise carbon fibers or powders. Relatively high and relatively low water transfer particle density regions alternate across the porous diffusion media. A first major face of the media may be collectively more hydrophilic than the second major face and the second major face may be collectively more hydrophobic than the first major face. The diffusion media is positioned against the catalyst layer along the first major face of the diffusion media and against a flow field of the fuel cell along the second major face of the diffusion media. The porous diffusion media comprises hydrophobic material disposed along the second major face of the diffusion media.
摘要:
Gas diffusion media for use in fuel cells are provided that contain a pattern of deposited hydrophobic polymer such that less than 100% of the surface of the diffusion media is covered with hydrophobic polymer. The media are made by first wetting a sheet of carbon fiber paper in an aqueous emulsion of the hydrophobic polymer. The wetted sheet is contacted with a pattern member containing one or more openings oriented to correspond to a predetermined or desired pattern of hydrophobic polymer deposition. While still in contact with the pattern member, the sheet is heated or otherwise treated to cause evaporation of the water from the sheet. Evaporation while in contact with the pattern member takes place in such a way that hydrophobic polymer is concentrated in the sheet at the openings of the pattern member by the process of evaporation.
摘要:
A diffusion media and a scheme for spatially varying the parameters of the diffusion media to address issues related to water management in electrochemical cells and other devices employing the diffusion media are provided. A device is configured to convert a hydrogenous fuel source to electrical energy and comprises an electrochemical conversion assembly, first and second reactant inputs, first and second product outputs, and first and second diffusion media. The device is configured such that a mesoporous layer is carried along at least a portion of a major face of one of the first and second diffusion media substrates. The mesoporous layer comprises a hydrophilic carbonaceous component and a hydrophobic component. The mesoporous layer occupies a substantially greater portion of one of the high or low H2O regions of the device, relative to the other of the high or low H2O region of the device.