A method for preparing large graphene sheets in large scale includes steps of: under a mild condition, processing graphite powders with intercalation through an acid and an oxidant; washing away metal ions and inorganic ions in the graphite powders with dilute hydrochloric acid, then filtering and drying; and, finally processing with a heat treatment. The present invention breaks through a series of bottlenecks restricting an efficient preparation of graphene that result from a traditional method of using large amounts of deionized water to wash graphite oxide to be neutral, and easily realizes a batch production. A radial scale of the prepared graphene sheets is distributed from 20 um to 200 um.

A graphene producing method which is capable of increasing a size of each domain of graphene. A plasma CVD film formation device that activates a catalyst metal layer formed on a wafer; modifies the same into an activated catalyst metal layer; decomposes a C.sub.2H.sub.4 gas as a low reactivity carbon-containing gas by plasma in a space that opposes the wafer; and decomposes a C.sub.2H.sub.2 gas as a high reactivity carbon-containing gas by heat in the space.

A battery-powered analyte sensing system includes a printed battery and an analyte sensor. The printed battery includes an anode composed of a non-toxic biocompatible metal, a first carbon-based current collector in electrical contact with the anode, a three-dimensional hierarchical mesoporous carbon-based cathode, a second carbon-based current collector, and an electrolyte layer disposed between the anode and the cathode, the electrolyte layer configured to activate the printed battery when the electrolyte is released into one or both the anode and the cathode. The analyte sensor includes a sensing material and a reactive chemistry additive in the sensing material.

The invention provides a method of producing graphene. The method comprising: A) mixing graphite powders with a silk fibroin nanofiber solution, performing mechanical stirring to exfoliate graphite to form graphene flakes; wherein the silk fibroin nanofibers in the silk fibroin nanofiber solution have a crystallinity of 40% or above; the silk fibroin nanofibers have a diameter of 10 to 30 nm; the silk fibroin nanofibers have a length of 100 nm to 3 μm; the mechanical stirring has a shearing speed of 1,000 to 50,000 rpm; and the duration of the mechanical stirring is 10 min to 6 h; B) centrifuging the solution obtained in step A) after exfoliation to remove unexfoliated graphite; and C) centrifuging the centrifuged solution obtained in step B), and separating graphene from the silk fibroin nanofibers to obtain the graphene.

The first present invention is a graphite sheet having a thickness of not more than 9.6 μm and more than 50 nm and a thermal conductivity along the a-b plane direction at 25° C. of 1950 W/mK or more. The second present invention is a graphite sheet having a thickness in a range of less than 9.6 μm and 20 nm or more, an area of 9 mm2 or more, and a carrier mobility along the a-b plane direction at 25° C. of 8000 cm2/V.Math.sec or more.

The present invention relates to a method for preparing graphene which comprises subjecting expanded graphite to high speed homogenization to prepare a feed solution and then subjecting the same to high pressure homogenization, thereby increasing the degree of dispersion of expanded graphite in the feed solution and so improving the efficiency of high pressure homogenization. Therefore, the present method has features that the efficiency of graphene preparation is excellent and the size of graphene to be prepared is uniform, compared with a conventional process.

The invention relates to a material of porous graphene nanowires with a pore-rich structure, production methods and applications of the material of porous graphene nanowires. The method includes: synthesis of catalyst nanowires for porous graphene nanowires, chemical vapor deposition of a carbon source on the catalysts to grow graphene, removal of residual catalyst, and formation of the porous graphene nanowires. The porous graphene nanowires can be used as an electrochemical energy storage material, carriers of catalysts, a conductive material, an adsorption material, a desorption material, or the like.

Embodiments of the present disclosure describe a method of preparing a colloidal solution comprising preparing a salted aqueous solvent and dispersing a graphitic material in the salted aqueous solvent. Embodiments of the present disclosure further describe a method of treating a graphitic material comprising agitating a graphitic material in a salted aqueous solvent and removing residual chemical species to obtain a treated graphitic material. Embodiments of the present disclosure also describe a colloidal solution comprising a liquid medium and a treated graphitic material dispersed in the liquid medium sufficient to form a colloidal solution.

A method of manufacturing a graphene sheet comprising the steps of: providing a container containing liquid and a volume above the liquid; supplying carbon atoms to the volume; and allowing carbon atoms to settle on the surface of the liquid and to coalesce to form the graphene sheet.

There are provided a graphene having an oxygen atom content in a predetermined range or less and a carbon/oxygen weight ratio in a specific range to show excellent electrical and thermal conductivity properties, and a barrier property, and a method and an apparatus for preparing the graphene having excellent electrical and thermal conductivity properties and a barrier property by using a subcritical-state fluid or a supercritical-state fluid. According to the method and the apparatus for preparing the graphene, impurities such as graphene oxide, and the like, may be effectively removed, such that uniformity of the graphene to be prepared may be increased, and therefore, the graphene which is highly applicable as materials throughout the industry may be mass-produced.