9368results about "Graphene" patented technology

A process for producing nano-scaled graphene plates with each plate comprising a sheet of graphite plane or multiple sheets of graphite plane with the graphite plane comprising a two-dimensional hexagonal structure of carbon atoms. The process includes the primary steps of: (a) providing a powder of fine graphite particles comprising graphite crystallites with each crystallite comprising one sheet or normally a multiplicity of sheets of graphite plane bonded together; (b) exfoliating the graphite crystallites to form exfoliated graphite particles, which are characterized by having at least two graphite planes being either partially or fully separated from each other; and (c) subjecting the exfoliated graphite particles to a mechanical attrition treatment to further reduce at least one dimension of the particles to a nanometer scale, <100 nm, for producing the nano-scaled graphene plates.

A modified graphite oxide material contains a thermally exfoliated graphite oxide with a surface area of from about 300 m²/g to 2600 m²/g, wherein the thermally exfoliated graphite oxide displays no signature of the original graphite and/or graphite oxide, as determined by X-ray diffraction.

A transparent and conductive film comprising at least one network of graphene flakes is described herein. This film may further comprise an interpenetrating network of other nanostructures, a polymer and/or a functionalization agent(s). A method of fabricating the above device is also described, and may comprise depositing graphene flakes in solution and evaporating solvent therefrom.

Provided is a process for preparing graphene on a SiC substrate, based on metal film-assisted annealing, comprising the following steps: subjecting a SiC substrate to a standard cleaning process; placing the cleaned SiC substrate into a quartz tube and heating the quartz tube up to a temperature of 750 to 1150° C.; introducing CCl₄vapor into the quartz tube to react with SiC for a period of 20 to 100 minutes so as to generate a double-layered carbon film, wherein the CCl₄ vapor is carried by Ar gas; forming a metal film with a thickness of 350 to 600 nm on a Si substrate by electron beam deposition; placing the obtained double-layered carbon film sample onto the metal film; subsequently annealing them in an Ar atmosphere at a temperature of 900 to 1100° C. for 10-30 minutes so as to reconstitute the double-layered carbon film into double-layered graphene; and removing the metal film from the double-layered graphene, thereby obtaining double-layered graphene. Also provided is double-layered graphene prepared by said process.

Nanocomposite materials comprising a metal oxide bonded to at least one graphene material. The nanocomposite materials exhibit a specific capacity of at least twice that of the metal oxide material without the graphene at a charge/discharge rate greater than about 10C.

Disclosed is a nano-scaled graphene article comprising a non-woven aggregate of nano-scaled graphene platelets wherein each of the platelets comprises a graphene sheet or multiple graphene sheets and the platelets have a thickness no greater than 100 nm (preferably smaller than 10 nm) and platelets contact other platelets to define a plurality of conductive pathways along the article. The article has an exceptional thermal conductivity (typically greater than 500 Wm⁻¹K⁻¹) and excellent electrical conductivity (typically greater than 1,000 S/cm). Thin-film articles of the present invention can be used for thermal management in micro-electronic devices and for current-dissipating on an aircraft skin against lightning strikes.

The invention provides a preparation method of graphene, and particularly relates to a method for preparing biomass graphene employing cellulose as a raw material. The specific preparation method comprises the following steps: 1, preparing a catalyst solution; 2, carrying out ionic coordination and high-temperature deoxidization on cellulose and a catalyst, so as to obtain a precursor; 3, carrying out thermal treatment; 4, carrying out acid treatment, and drying to obtain the graphene, wherein the prepared graphene is uniform in morphology, has a single-layer or multi-layer two-dimensional layered structure; the dimension is 0.5-2 microns; and the electrical conductivity is 25,000-45,000S/m. The preparation method is simple in preparation technology, low in cost, high in yield, high in production safety, and controllable in product dimension and physical property; industrialized production can be realized; the graphene prepared by the method can be applied to electrode materials of super capacitors and lithium ion batteries, and can also be added to resin and rubber as an additive; and the physical property of the material can be improved.

The invention relates to a graphene-based novel material and a chemical vapor deposition preparation technology thereof, in particular to graphene foam with a three dimensional fully connected network and a macroscopic quantity preparation method thereof. The method is suitable for a mass preparation of the graphene foam with high qualities. Three dimensional connected graphene can grow by catalytic cracking of carbon source gases on the surface of a three dimensional porous metal through the chemical vapor deposition technology, and a porous foam-shaped graphene three dimensional macroscopic body can be obtained after a porous metal base is removed by dissolving subsequently. According to the graphene foam with the three dimensional fully connected network and the macroscopic quantity preparation method thereof, a simple template replication method is used for preparing the three dimensional connected graphene macroscopic body, and the method has the advantages that the operation is simple and convenient, the rate of production is high, and the adjustment and control of the structure are easy. The graphene foam forms the fully connected network in a seamless connection mode, has a low density, a high porosity and specific surface area and excellent capabilities of charge conduction and heat conduction and establishes a foundation for applications of graphene in fields of electric conduction, thermally conductive composite materials, electromagnetic shielding, wave absorbing, catalysis, sensing and energy storage materials and the like.

Disclosed herein is a reduced graphene oxide doped with a dopant, and a thin layer, a transparent electrode, a display device and a solar cell including the reduced graphene oxide. The reduced graphene oxide doped with a dopant includes an organic dopant and/or an inorganic dopant.

The present invention provides methods of forming graphene films on various non-catalyst surfaces by applying a carbon source and a catalyst to the surface and initiating graphene film formation. In some embodiments, graphene film formation may be initiated by induction heating. In some embodiments, the carbon source is applied to the non-catalyst surface before the catalyst is applied to the surface. In other embodiments, the catalyst is applied to the non-catalyst surface before the carbon source is applied to the surface. In further embodiments, the catalyst and the carbon source are applied to the non-catalyst surface at the same time. Further embodiments of the present invention may also include a step of separating the catalyst from the formed graphene film, such as by acid etching.

A polymer composition, containing a polymer matrix which contains an elastomer; and a functional graphene which displays no signature of graphite and/or graphite oxide, as determined by X-ray diffraction, exhibits excellent strength, toughness, modulus, thermal stability and electrical conductivity.

A method for producing isolatable and dispersible graphene sheets, wherein the graphene sheets may be tailored to be soluble in aqueous, non-aqueous or semi-aqueous solutions. The water soluble graphene sheets may be used to produce a metal nanoparticle-graphene composite having a specific surface area that is 20 times greater than aggregated graphene sheets. Graphene sheets that are soluble in organic solvents may be used to make graphene-polymer composites.

Graphene layers, hexagonal boron nitride layers, as well as other materials made of primarily sp2 bonded atoms and associated methods are disclosed. In one aspect, for example, a method of forming a graphene layer is provided. Such a method may include mixing a carbon source with a horizontally oriented molten solvent, precipitating the carbon source from the molten solvent to form a graphite layer across the molten solvent, and separating the graphite layer into a plurality of graphene layers.

This invention provides a nano-scaled graphene platelet (NGP) having a thickness no greater than 100 nm and a length-to-width ratio no less than 3 (preferably greater than 10). The NGP with a high length-to-width ratio can be prepared by using a method comprising (a) intercalating a carbon fiber or graphite fiber with an intercalate to form an intercalated fiber; (b) exfoliating the intercalated fiber to obtain an exfoliated fiber comprising graphene sheets or flakes; and (c) separating the graphene sheets or flakes to obtain nano-scaled graphene platelets. The invention also provides a nanocomposite material comprising an NGP with a high length-to-width ratio. Such a nanocomposite can become electrically conductive with a small weight fraction of NGPs. Conductive composites are particularly useful for shielding of sensitive electronic equipment against electromagnetic interference (EMI) or radio frequency interference (RFI), and for electrostatic charge dissipation.

Certain example embodiments of this invention relate to the use of graphene as a transparent conductive coating (TCC). In certain example embodiments, graphene thin films grown on large areas hetero-epitaxially, e.g., on a catalyst thin film, from a hydrocarbon gas (such as, for example, C₂H₂, CH₄, or the like). The graphene thin films of certain example embodiments may be doped or undoped. In certain example embodiments, graphene thin films, once formed, may be lifted off of their carrier substrates and transferred to receiving substrates, e.g., for inclusion in an intermediate or final product. Graphene grown, lifted, and transferred in this way may exhibit low sheet resistances (e.g., less than 150 ohms/square and lower when doped) and high transmission values (e.g., at least in the visible and infrared spectra).

Compositions comprising at least one polymer binder, graphene sheets, and graphite, wherein the ratio by weight of graphite to graphene sheets is from about 40:60 to about 98:2.

A method of producing nano-scaled graphene platelets with an average thickness smaller than 30 nm from a layered graphite material. The method comprises (a) forming a carboxylic acid-intercalated graphite compound by an electrochemical reaction which uses a carboxylic acid as both an electrolyte and an intercalate source, the layered graphite material as an anode material, and a metal or graphite as a cathode material, and wherein a current is imposed upon the cathode and the anode at a current density for a duration of time sufficient for effecting the electrochemical reaction; (b) exposing the intercalated graphite compound to a thermal shock to produce exfoliated graphite; and (c) subjecting the exfoliated graphite to a mechanical shearing treatment to produce the nano-scaled graphene platelets. Preferred carboxylic acids are formic acid and acetic acid. The exfoliation step in the instant invention does not involve the evolution of undesirable species, such as NO_x and SO_x, which are common by-products of exfoliating conventional sulfuric or nitric acid-intercalated graphite compounds. The nano-scaled platelets are candidate reinforcement fillers for polymer nanocomposites. Nano-scaled graphene platelets are much lower-cost alternatives to carbon nano-tubes or carbon nano-fibers.

Provided in this invention is a process for producing chemically functionalized nano graphene materials, known as nano graphene platelets (NGPs), graphene nano sheets, or graphene nano ribbons. Subsequently, a polymer can be grafted to a functional group of the resulting functionalized NGPs. In one preferred embodiment, the process comprises (A) dispersing a pristine graphite material and an azide or bi-radical compound in a liquid medium comprising to form a suspension; and (B) subjecting the suspension to direct ultrasonication with to ultrasonic waves of a desired intensity or power level for a length of time sufficient to produce nano graphene platelets and to enable a chemical reaction to occur between the nano graphene platelets and the azide or bi-radical compound to produce the functionalized nano graphene material. Concurrent production and functionalization of NGPs directly from pristine graphitic materials can be achieved in one step and in the same reactor.

Provided is a simple, fast, scalable, and environmentally benign method of producing graphene-embraced or encapsulated particles of a battery electrode active material directly from a graphitic material, the method comprising: a) mixing graphitic material particles and multiple particles of a solid electrode active material to form a mixture in an impacting chamber of an energy impacting apparatus, wherein the graphitic material has never been intercalated, oxidized, or exfoliated and the chamber contains therein no previously produced graphene sheets and no ball-milling media; b) operating the energy impacting apparatus with a frequency and an intensity for a length of time sufficient for transferring graphene sheets from the graphitic material to surfaces of electrode active material particles to produce graphene-embraced electrode active material particles; and c) recovering the particles from the impacting chamber. Also provided is a mass of the graphene-embraced particles, electrode containing such particles, and battery containing this electrode.

The invention relates to expanded graphite and methods of making the graphite and products that can be made from the graphite made from the inventive process. The invention includes the step of introducing a fluid into at least one of a plurality of interstices of graphite flake, wherein the fluid comprises at least one of a sub-critical point fluid, a near critical point fluid, or a supercritical fluid. The graphite flake is also intercalated with an intercalant and optionally an oxidizing agent. The invention may further include novel techniques of exfoliating the graphite. The invention may be practiced to make nano-sized graphite particles and also graphite composites. Preferred composites which may be made in accordance with the invention include conductive polymeric composites (thermally or electrically), paint composites, battery composites, capacitor composites, and pollution abatement catalyst support composites.

The invention relates to a preparation method of a graphene heat conducting membrane. The method comprises the following steps: filtrating or coating graphene oxide dispersed in a solvent to obtain a graphene oxide membrane; then, reducing the graphene oxide membrane at a high temperature to obtain the graphene heat conducting membrane. The preparation method of the graphene heat conducting membrane, provided by the invention, is simple in technique, simple in operation and easy in control on conditions, and the graphene heat conducting membrane provided by the invention is controllable in shape, size and thickness and relatively high in heat conductivity.

The present invention provides a method of producing pristine or non-oxidized nano graphene platelets (NGPs) that are highly conductive. The method comprises: (a) providing a pristine graphitic material comprising at least a graphite crystallite having at least a graphene plane and an edge surface; (b) dispersing multiple particles of the pristine graphitic material in a liquid medium containing therein no surfactant to produce a suspension, wherein the multiple particles in the liquid have a concentration greater than 0.1 mg/mL and the liquid medium is characterized by having a surface tension that enables wetting of the liquid on a graphene plane exhibiting a contact angle less than 90 degrees; and (c) exposing the suspension to direct ultrasonication at a sufficient energy or intensity level for a sufficient length of time to produce the NGPs. Pristine NGPs can be used as a conductive additive in transparent electrodes for solar cells or flat panel displays (e.g., to replace expensive indium-tin oxide), battery and supercapacitor electrodes, and nanocomposites for electromagnetic wave interference (EMI) shielding, static charge dissipation, and fuel cell bipolar plate applications.

A method of producing nano-scaled graphene platelets (NGPs) having an average thickness no greater than 50 nm, typically less than 2 nm, and, in many cases, no greater than 1 nm. The method comprises (a) intercalating a supply of meso-carbon microbeads (MCMBs) to produce intercalated MCMBs; and (b) exfoliating the intercalated MCMBs at a temperature and a pressure for a sufficient period of time to produce the desired NGPs. Optionally, the exfoliated product may be subjected to a mechanical shearing treatment, such as air milling, air jet milling, ball milling, pressurized fluid milling, rotating-blade grinding, or ultrasonicating. The NGPs are excellent reinforcement fillers for a range of matrix materials to produce nanocomposites. Nano-scaled graphene platelets are much lower-cost alternatives to carbon nano-tubes or carbon nano-fibers.

A specific embodiment of the present invention is a process for continuously producing a porous solid film of spacer-modified nano graphene platelets for supercapacitor electrode applications. This process comprises: (a) dissolving a precursor material in a solvent to form a precursor solution and dispersing multiple nano graphene platelets into the solution to form a suspension; (b) continuously delivering and forming the suspension into a layer of solid film composed of precursor material-coated graphene platelets overlapping one another, and removing the solvent from the solid film (e.g., analogous to a paper-making, mat-making, or web-making procedure); (c) continuously converting the precursor material into nodules bonded to surfaces of graphene platelets to form a porous solid film composed of spacer-modified graphene platelets; and (d) continuously collecting the porous solid film on a collector (e.g., a winding roller). The roll of porous solid film (mat, paper, or web) can then be cut into pieces for used as supercapacitor electrodes.

The invention discloses a preparation method of a graphene dispersion liquid. The preparation method of the graphene dispersion liquid comprises the following steps: placing an expanded graphite compacted electrode and a metallic or non-metallic electrode material in an electrolyte solution as an anode and a cathode respectively, and applying a voltage of 1-20V and/or a current having a density of 1-200mA/cm<2> between the anode and the cathode for carrying out an electrochemical reaction for 1-120min; and washing an anode product obtained after the electrochemical reaction, adding to a dispersant, and carrying out ultrasonic or/and mechanical stirring dispersion to obtain the graphene dispersion liquid. The invention also discloses a preparation method of a graphene film. The graphene dispersion liquid forms the graphene film on a substrate in a filter film forming mode or a coating film forming mode or a natural deposition mode. The preparation methods have the advantages of simple process, easy operation, high controllability, low cost and mild reaction condition, and are suitable for the industrialized large-scale production.

The invention provides nitrogen mixed grapheme hydrogel of which the water content is 90 to 99.5 percent, the electric conductivity is 10-3-100 S/m, and the molar ratio of N and C is 1 to 25 percent. The invention further provides nitrogen mixed aerogel of which the molar ratio of N and C is 2 to 20 percent, the molar ratio of C and O is 15 to 5, nitrogen atoms existing in the form of amidogen nitrogen accounts for 40 to 70 percent, pyridine type nitrogen accounts for 10 to 40 percent, graphite type nitrogen accounts for 10 to 30 percent, the specific area is 300 to 1500 m<2>/g, the apertures which are micropore account for 10 to 20 percent, the apertures which are mesoporous 20 to 50 percent, the apertures which are macropore 30 to 70 percent, the apparent density is 0.01 to 0.2 g/cm<3>, the pore volume is 5 to 20 cm<3>/g, and the electric conductivity is 1 to 1000 S/m. The nitrogen mixed grapheme hydrogel or aerogel and preparation method thereof provided by the invention has the characteristics that the operation is simple, the equipment requirement is low, the production efficiency is high, the scale-up of the technology is easy, the nitrogen mixed content is controllable and the compounding with other functional substances is simple.