1058 results about "Graphene flake" patented technology

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.

Touch screen displays comprising at least one nanostructure-film, and fabrication methods thereof, are discussed. Nanostructure-films may comprise, for example, a network(s) of nanotubes, nanowires, nanoparticles and/or graphene flakes. Such films are preferably at least semi-transparent and relatively flexible, making them well-suited for use in a variety of touch screen applications.

The invention relates to a graphene composite material and a preparation method thereof. The graphene composite material provided by the invention is characterized in that a graphene material plate fixed on a metallic matrix serves as a carrier, and the elementary substance and/or a compound are compounded on the graphene surface. Meanwhile, the invention also discloses a method for preparing the graphene composite material. The graphene composite material prepared by the invention is opened between graphene sheets and is compounded with a chemical substance under the condition that a space body structure is formed, and the obtained material has high conductivity, high specific surface area and excellent performance of low electrical resistivity between the sheets, and can be widely applied to the fields of energy storage materials such as lithium ion batteries, super-capacitors, super lead carbon batteries, super nickel-carbon electrodes, solar energy and fuel cells, the field of heat dissipation materials, the field of environment-friendly adsorbing materials, the field of sea water desalination materials, the field of photoelectric sensor materials, the biological relevance field, the field of catalyst materials and the fields of conductive ink and coating materials.

The present invention provides a process for producing a graphene-enhanced anode active material for use in a lithium battery. The process comprises (a) providing a continuous film of a graphene material into a deposition zone; (b) introducing vapor or atoms of a precursor anode active material into the deposition zone, allowing the vapor or atoms to deposit onto a surface of the graphene material film to form a sheet of an anode active material-coated graphene material; and (c) mechanically breaking this sheet into multiple pieces of anode active material-coated graphene; wherein the graphene material is in an amount of from 0.1% to 99.5% by weight and the anode active material is in an amount of at least 0.5% by weight, all based on the total weight of the graphene material and the anode active material combined.

The present invention provides a dispersible and electrically conductive nano graphene platelet (NGP) material comprising at least a single-layer or multiple-layer graphene sheet, wherein the NGP material has an oxygen content no greater than 25% by weight and no less than 5% by weight. This NGP material can be produced by: (a) preparing a pristine NGP material from a graphitic material; and (b) subjecting the pristine NGP material to an oxidation treatment. Alternatively, the production process may comprise: (A) preparing a graphite oxide (GO) from a laminar graphite material; (b) exposing the GO to a first temperature for a first period of time to obtain exfoliated graphite; and (c) exposing the exfoliated graphite to a second temperature in a protective atmosphere for a second period of time. Conductive NGPs can find applications in transparent electrodes for solar cells or flat panel displays, additives for battery and supercapacitor electrodes, conductive nanocomposite for electromagnetic wave interference (EMI) shielding and static charge dissipation, etc.

An interpenetrating network assembly with a network of connected flakes of nano-scale crystalline carbon and nano-scale particles of an electroactive material interconnected with the carbon flakes is provided. The network assemblies are particularly suited for energy storage applications that use metal oxide electroactive materials and a single charge collector or a source and drain. Interpenetrating networks of graphene flakes and metal oxide nanosheets can form independent pathways between source and drain. Nano-scale conductive materials such as metal nanowires, carbon nanotubes, activated carbon or carbon black can be included as part of the conductive network to improve charge transfer.

Described is an electrode comprising and preferably consisting of electronically active material (EAM) in nanoparticulate form and a matrix, said matrix consisting of a pyrolization product with therein incorporated graphene flakes and optionally an ionic lithium source. Also described are methods for producing a particle based, especially a fiber based, electrode material comprising a matrix formed from pyrolized material incorporating graphene flakes and rechargeable batteries comprising such electrodes.

The invention relates to a preparation method of a graphene oxide/waterborne polyurethane nanometer composite material. Especially, the preparation method comprises the following steps of: utilizing gamma-aminopropyl triethoxysilane (KH550) to carry out surface modification (functionalization of graphene oxide) onto graphene oxide; lowering hydrophily of a graphene oxide sheet layer; improving dispersion of the graphene oxide sheet layer in an organic solvent and compatibility of the graphene oxide and the polymer; and utilizing an in-situ polymerization method to prepare the graphene oxide/waterborne polyurethane nanometer composite material. The preparation method of the graphene oxide/waterborne polyurethane nanometer composite material belongs to the preparation field of composite materials.

The invention discloses a method for preparing high-strength conductive graphene fiber by a large-size graphene oxide sheet. The method comprises the steps of: oxidizing expanded graphite and obtaining graphene oxide; dispersing the graphene oxide into water, carrying out centrifugal classification treatment on the dispersed graphene oxide, and obtaining the large-size even graphene oxide sheet; and finally, dispersing the graphene oxide into water or polar organic solvent, preparing spinning solution liquid crystal sol with the mass concentration of 1-20%, transferring the spinning solution liquid crystal sol into a spinning device, continuously squeezing spinning solution out from a spinning head capillary tube at the uniform velocity, leading the squeezed spinning solution into solidification liquid, drying the solidified primary fiber, obtaining graphene oxide fiber, and then obtaining the graphene fiber by chemical reduction. A spinning technology is simple; and the obtained graphene fiber is good in electrical conductivity, excellent in mechanical property and better in toughness, can be woven into pure-graphene fiber cloth, and also can be woven with other fibers in a blending way so as to make various functional fabrics, so that the high-strength conductive graphene fiber can be used for replacing carbon fiber in a plurality of fields.

The invention relates to a preparation method for graphene, especially to a method for preparing high-quality graphene through electrochemical high-efficiency exfoliation. The method mainly overcomes the technical problems that the honeycomb lattice structure of graphene is severely destroyed in the process of oxidation, an obtained membrane resistance is 1 K to 70 K omega/square (wherein light transmittance is less than 80%), the resistance is too high and much higher than requirements of ITO, etc. The method comprises the following steps: with graphite as a positive electrode and a platinum filament as a negative electrode, repeatedly applying high offset voltage and negative offset voltage on the graphite electrode, which enables graphite to be rapidly disassociated and decomposed into double-layer graphene floating on the surface of an electrolyte; collecting graphene and then filtering and drying graphene; dispersing obtained powder of a graphene film in a DMF solution; and carrying out water-bath ultrasonic treatment and centrifugation so as to obtain desired 1.5-nm-grade graphene flakes.

A gel film or an isolated gel film comprising sheets of graphene or chemically converted graphene at least partially separated by a dispersion medium, such as water, and arranged in a substantially planar manner to form an electrically conductive matrix.

A graphene nanomesh includes a sheet of graphene having a plurality of periodically arranged apertures, wherein the plurality of apertures have a substantially uniform periodicity and substantially uniform neck width. The graphene nanomesh can open up a large band gap in a sheet of graphene to create a semiconducting thin film. The periodicity and neck width of the apertures formed in the graphene nanomesh may be tuned to alter the electrical properties of the graphene nanomesh. The graphene nanomesh is prepared with block copolymer lithography. Graphene nanomesh field-effect transistors (FETs) can support currents nearly 100 times greater than individual graphene nanoribbon devices and the on-off ratio, which is comparable with values achieved in nanoribbon devices, can be tuned by varying the neck width. The graphene nanomesh may also be incorporated into FET-type sensor devices.

The invention relates to a preparation method of functional nano-graphene, belonging to the technical field of nano-graphene functional material. The method comprises the following steps: adding graphite oxide in water while adding one or more kinds of penetrants, stirring with ultrasonic wave or a rapid machine to form brown or black uniform suspension, heating to 70-100 DEG C, refluxing, washingwith water and drying to obtain the nano-graphene containing monolayer or multilayer graphene, wherein in the mixing process, graphite oxide absorbs penetrants and performs interlaminar swelling andthe swelled graphite oxide becomes loose and performs dissociation under the ultrasonic oscillation or the mechanical agitation of the rapid machine. The analysis of TEM finds that the nano-graphene has fold property and high radius-thickness ratio, simple technological process, reliable production principle, accessible raw material, low cost, good nanometer functionality, stable structural performance and good application effect.

The invention discloses a graphene-carbon nano-tube composite nanofiltration membrane with high flux and a preparation method of the graphene-carbon nano-tube composite nanofiltration membrane. The composite nanofiltration membrane is prepared by uniformly depositing a full-carbon selective separation layer on a porous polymer supporting layer by using the method disclosed by the invention, wherein the full-carbon selective separation layer is formed by compounding and assembling graphene and a carbon nano-tube. By using the method disclosed by the invention, the carbon nano-tube can be effectively intercalated among graphene sheet layers which are compactly stacked. The nanofiltration membrane prepared by using the preparation method disclosed by the invention is high in water flux, good in pollution resistance, high in retention rate (approach to 100%) of organic dyes, relatively high in salt removing rate of the organic dyes and capable of keeping relatively high flux under the conditions of high operation pressure and high salinity. The preparation method disclosed by the invention is simple and easy, strong in controllability, relatively low in production cost and free of pollution so as to have favorable application prospects in the nanofiltration field.

The invention discloses a method for preparing a polyamide-amine in-situ intercalation graphene composite material. The method comprises the following steps of: (1) dispersing graphite in an imidazole-compound-containing organic solvent with ultrasonic, and centrifuging to obtain multi-layer graphene suspension; and (2) polymerizing to generate polyamide-amine in the multilayer graphene by adopting an in-situ polymerization method to prepare the polyamide-amine in-situ intercalation graphene composite material. According to the method, natural graphite is directly subjected to ultrasonic exfoliation in the organic solvent to obtain single-layer or multi-layer graphene suspension, the original sp2 structure of the graphene is slightly damaged because an oxidation step is not carried out, the polyamide-amine in-situ intercalation graphene composite material is prepared by using an in-situ polymerization method, so that graphene laminas are spread, interlamellar spacings are enlarged, the polyamide-amine on the surface of the graphene functionally prevents agglomeration of the graphene laminas, the graphene laminas are uniformly dispersed, and the product has good stability and is hardly precipitated.

A method of making a composition, comprising: (1) oxidizing graphite to graphite oxide using at least one sulfur-containing reagent, (2) exfoliating the graphite oxide to form graphene sheets, and (3) blending the graphene sheets with elemental sulfur and/or at least one organosulfur compound, wherein the graphene sheets comprise at least about 1 weight percent sulfur. The composition may be made into an electrode that may be used in batteries, including lithium sulfur batteries.

The invention discloses a method for preparing a reduced graphene oxide heat conductive film. The method comprises the following steps: adding graphite oxide into the deionized water to perform ultrasonic treatment, centrifuging the obtained suspension solution for 5-20 min at the speed of 2000-3000 rpm, getting a supernate, drying and grinding to obtain the graphene oxide; and adding the obtained graphene oxide into a solvent to perform ultrasonic treatment to obtain a graphene oxide dispersed solution with the concentration of 1-5 mg/ml, performing vacuum filtration by a millipore filter, drying the obtained filter cake with the filter membrane, stripping the filter cake from the filter membrane, exerting the pressure of 0-10 MPa to the obtained graphene oxide, under the atmosphere of nitrogen, argon or helium, and processing for 2-8h at the temperature of 600-1000 DEG C to obtain the reduced graphene oxide heat conductive film with high heat conductivity, high reduction degree, high graphene lamellar surface inner orientation degree, smooth surface, good flexibility, wide curl degree without crack and small interlamellar spacing. The preparation method is simple and the reduced graphene oxide heat conductive film is easy for realization of industrial production.

The invention provides a grading three-dimensional porous graphene/titanium dioxide photocatalyst and preparation method thereof. The photocatalyst is composed by a three-dimensional grapheme framework and nano titanium dioxide particles; the grahene is provided with a macroporous structure; titanium dioxide is mesoporous titanium dioxide; the macropores and the mesopores are communicated; the nano titanium dioxide particles are scattered on a grapheme nano sheet; the surfaces of nano titanium dioxide microspheres are wrapped with graphene nano sheets; the macropores of the graphene are filled with the nano titanium dioxide microspheres. The photocatalyst with a three-dimensional structure can not only prevent the graphene sheet layers from stacking, but also scatter titanium dioxide particles excellently, and is high in specific surface area; besides, samples can be used for photocatalysis degradation of methylene blue, and the methylene blue can be fully degraded in 25 minutes. The preparation method provides a new thought for preparation of the photocatalyst, and has a potential application value in the fields of energy sources and environment.

The invention relates to a graphene enhanced magnesium-based composite and a preparing method thereof, and belongs to the technical field of composites. In the inert atmosphere, graphene with a certain lamella size and pure magnesium particles are subjected to ball-milling treatment, and meanwhile peeling of a graphene lamella and mixing between the graphene lamella and the pure magnesium particles are achieved; an ultrasonic dispersing and mechanical stirring technology is adopted, the peeled graphene lamella is further dispersed in a liquid phase, the pure magnesium particles are inserted in the parts among graphene layers in the stirring process, and the solid phase interval and sufficient mixing between the pure magnesium particles and the graphene layers are achieved; the compactness of graphene/pure magnesium particle composite powder is enhanced through a thermal extrusion technology, a magnesium-based precursor containing graphene is obtained, and the graphene enhanced magnesium-based composite is finally obtained through an alloy component blending and stirring casting method. The method technology is simple and convenient to conduct, environment friendliness is achieved, and sufficient dispersing of graphene in a magnesium base body is achieved. The graphene/magnesium-based composite with the enhanced mechanical performance is obtained, and wide application prospects are achieved in the fields such as aerospace, automobiles and electronics.