Abstract: A method of modifying the surface of carbon materials such as vapor grown carbon nanofibers is provided in which silicon is deposited on vapor grown carbon nanofibers using a chemical vapor deposition process. The resulting silicon-carbon alloy may be used as an anode in a rechargeable lithium ion battery.

Abstract: A method of modifying the surface of carbon materials such as vapor grown carbon nanofibers is provided in which silicon is deposited on vapor grown carbon nanofibers using a chemical vapor deposition process. The resulting silicon-carbon alloy may be used as an anode in a rechargeable lithium ion battery.

Abstract: Methods of making a cathode element for an electrochemical cell. The methods comprise providing hollow carbon nanotubes and a sulfur source in a closed environment. Sulfur is deposited within an interior of the hollow carbon nanotube. The method includes cleaning an exterior surface of the carbon nanotubes and incorporating the carbon nanotubes into a cathode element. A cathodic material for a lithium-sulfur electrochemical cell is also provided. The material comprises a plurality of stacked-cone carbon nanotubes. Each nanotube defines a hollow interior and has a substantially continuous exterior surface area. Elemental sulfur is disposed within the hollow interior of each nanotube.

Abstract: A method of depositing silicon on carbon nanomaterials such as vapor grown carbon nanofibers, nanomats, or nanofiber powder is provided. The method includes flowing a silicon-containing precursor gas in contact with the carbon nanomaterial such that silicon is deposited on the exterior surface and within the hollow core of the carbon nanomaterials. A protective carbon coating may be deposited on the silicon-coated nanomaterials. The resulting nanocomposite materials may be used as anodes in lithium ion batteries.

Abstract: Methods of making a cathode element for an electrochemical cell. The methods comprise providing hollow carbon nanotubes and a sulfur source in a closed environment. Sulfur is deposited within an interior of the hollow carbon nanotube. The method includes cleaning an exterior surface of the carbon nanotubes and incorporating the carbon nanotubes into a cathode element. A cathodic material for a lithium-sulfur electrochemical cell is also provided. The material comprises a plurality of stacked-cone carbon nanotubes. Each nanotube defines a hollow interior and has a substantially continuous exterior surface area. Elemental sulfur is disposed within the hollow interior of each nanotube.

Abstract: A method of modifying the surface of carbon materials such as vapor grown carbon nanofibers is provided in which silicon is deposited on vapor grown carbon nanofibers using a chemical vapor deposition process. The resulting silicon-carbon alloy may be used as an anode in a rechargeable lithium ion battery.

Abstract: A process for fabricating a carbon composite structure that is lightweight, structurally sound, and characterized by high heat capacity. A carbon structure is devised with cavities therein receiving a phase change medium. The phase change medium demonstrates both high energy absorption capacity and high thermal conductivity and is formed from a carbon fiber to establish a high porosity medium having a large volume fraction. The surface energy of the carbon fibers is enhanced in various ways as by deposition of a carbide former, a metallurgical coating or a precursor liquid or by electroplating or etching the surfaces of the carbon fibers. The enhanced surface energy allows for the retention of phase change material.

Abstract: A process for fabricating a carbon composite structure that is lightweight, structurally sound, and characterized by high heat capacity. A carbon structure is devised with cavities therein receiving a phase change medium. The phase change medium demonstrates both high energy absorption capacity and high thermal conductivity and is formed from a carbon fiber to establish a high porosity medium having a large volume fraction. The surface energy of the carbon fibers is enhanced in various ways as by deposition of a carbide former, a metallurgical coating or a precursor liquid or by electroplating or etching the surfaces of the carbon fibers. The enhanced surface energy allows for the retention of phase change material.

Abstract: High surface energy vapor grown carbon fibers and methods of making such fibers. The high surface energy vapor grown carbon fibers of the present invention have a surface energy greater than about 75 mJ/m2 without post-manufacture treatment.

Abstract: A diamond/carbon/carbon composite is provided comprising a carbon/carbon composite having a polycrystalline diamond film deposited thereon. The carbon/carbon composite comprises a preform of interwoven carbon fibers comprising vapor grown carbon fibers. The preferred method of producing the composite involves chemical vapor infiltration of the pyrolytic carbon into the interstices of the preform, followed by microwave plasma enhanced chemical vapor deposition of the diamond film on the carbon/carbon composite. The resulting diamond/carbon/carbon composite is useful as an integral dielectric heat sink for electronic systems in spacecraft, aircraft and supercomputers due to its thermal management properties. Such a heat sink can be made by depositing metallic circuits on the diamond layer of the diamond/carbon/carbon composite.

Abstract: A method for producing a diamond/carbon/carbon composite is provided which includes the steps of densifying a preform of interwoven vapor grown carbon fibers form a carbon/carbon composite, and then depositing a polycrystalline diamond film on the carbon/carbon composite. The preform may be densified by depositing pyrolyric carbon into the interstices of the preform, either by a chemical vapor infiltration process or by a pitch infiltration process. The polycrystalline diamond film is deposited on the carbon/carbon composite by a microwave plasma enhanced chemical vapor deposition process. The resulting diamond/carbon/carbon composite can be utilized as an integral dielectric heat sink by depositing metallic circuits on the diamond layer of the diamond/carbon/carbon composite.