▎ 摘　　要

NOVELTY - Preparing carbon nanotube-graphene composite, comprises: providing a graphite (202) substrate that includes stacked graphene sheets (208); providing a carbon nanotube chemical vapor deposition catalyst; inserting the carbon nanotube chemical vapor deposition catalyst between at least a portion of the stacked graphene sheets of the graphite substrate; and heating the carbon nanotube chemical vapor deposition catalyst in contact with a chemical vapor deposition feedstock to a temperature suitable for growing carbon nanotubes (216). USE - The method is useful for preparing carbon nanotube-graphene composite. DETAILED DESCRIPTION - Preparing a carbon nanotube-graphene composite, comprises: providing a graphite substrate that includes stacked graphene sheets; providing a carbon nanotube chemical vapor deposition catalyst; inserting the carbon nanotube chemical vapor deposition catalyst between at least a portion of the stacked graphene sheets of the graphite substrate; heating the carbon nanotube chemical vapor deposition catalyst in contact with a chemical vapor deposition feedstock to a temperature suitable for growing carbon nanotubes; growing carbon nanotubes from the heated carbon nanotube chemical vapor deposition catalyst between the stacked graphene sheets of the graphite substrate for a period of time sufficient to separate at least a portion of the stacked graphene sheets of the graphite substrate using the growing carbon nanotubes; and cooling the carbon nanotubes and the separated graphene sheets to provide the carbon nanotube-graphene composite. INDEPENDENT CLAIMS are also included for: (1) a system for preparing a carbon nanotube-graphene composite, comprising a reaction chamber configured to receive a graphite substrate that includes stacked graphene sheets, a chemical reservoir configured to direct the carbon nanotube chemical vapor deposition catalyst or a precursor of it to the reaction chamber, a gas source configured to direct to the reaction chamber, a reductant gas, an oxidant gas, an inert gas, and a chemical vapor deposition feedstock suited for carbon nanotube deposition, a pressure sensor configured to measure a pressure in the reaction chamber, a heater configured to heat the reaction chamber at 550-1000 degrees C, a temperature sensor configured to measure a temperature in the reaction chamber, and a controller coupled to the reaction chamber, the chemical reservoir, the gas source, the pressure sensor, the heater, and the temperature sensor, where the controller is programmable to provide a graphite substrate that includes stacked graphene sheets to the reaction chamber, provide a carbon nanotube chemical vapor deposition catalyst to the reaction chamber, insert the carbon nanotube chemical vapor deposition catalyst between at least a portion of the stacked graphene sheets of the graphite substrate, employ the heater and the temperature sensor to heat the carbon nanotube chemical vapor deposition catalyst in contact with a chemical vapor deposition feedstock provided by the gas source to a temperature selected to grow the carbon nanotubes, grow the carbon nanotubes from the heated carbon nanotube chemical vapor deposition catalyst between the stacked graphene sheets of the graphite substrate for a period of time sufficient to separate at least a portion of the stacked graphene sheets of the graphite substrate with the carbon nanotubes, and employ the temperature sensor to monitor a reduction in temperature of the carbon nanotubes and the separated graphene sheets to provide the carbon nanotube-graphene composite; (2) the carbon nanotube-graphene composite, comprising an array of stacked graphene sheets arranged in a substantially graphitic structure, and a collection of carbon nanotubes disposed between at least a portion of the stacked graphene sheets, where the carbon nanotubes separate the portion of the stacked graphene sheets by a distance of at least 10 nm; and (3) a capacitor device, comprising a first electrode, a second electrode, a first carbon nanotube-graphene composite conductively coupled to the first electrode, a second carbon nanotube-graphene composite conductively coupled to the second electrode, where the first and second carbon nanotube graphene composites each include an array of graphene sheets arranged in a substantially graphitic structure, and a collection of carbon nanotubes disposed between at least a portion of the stacked graphene sheets, and the carbon nanotubes separate the portion of the stacked graphene sheets by a distance of at least 10 nm. DESCRIPTION OF DRAWING(S) - The figure shows a schematic view of methods of making carbon nanotube-graphene composites. Graphite (202) Catalyst precursor (206) Graphene sheets (208) Catalyst nanoparticles (210) Carbon nanotubes (216)