1179 results about "Graphene nanoplatelet" patented technology

A nanographitic composite for use as an anode in a lithium ion battery includes nanoscale particles of an electroactive material; and a plurality of graphene nanoplatelets having a thickness of 0.34 nm to 5 nm and lateral dimensions of less than 900 nm, wherein the electroactive particle has an average particle size that is larger than the average lateral dimension of the graphene nanoplatelets, and the graphene nanoplatelets coat at least a portion of the nanoscale particles to form a porous nanographitic layer made up of overlapping graphene nanoplatelets.

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.

The invention discloses a graphene nano sheet/MoS2 composite nano material and a synthesis method thereof. The method comprises the following steps of: preparing a graphite oxide nano sheet from graphite by using a chemical oxidation method, then dissolving molybdate into deionized water to form a solution of 0.02 to 0.07M, and adding thioacetamide or thiourea serving as a sulfur source and a reducer, wherein the mass ratio of the thioacetamide or the thiourea to the molybdate is 5:1-12:1; and adding the graphite oxide nano sheet into the solution, performing ultrasonic treatment for 1 to 2 hours so that the graphite oxide nano sheet is fully dispersed in a hydrothermal reaction solution, transferring the mixture into a hydrothermal reaction kettle, sealing, reacting for 20 to 36 hours at the temperature of between 220 and 260 DEG C, and obtaining the graphene nano sheet/molybdenum disulfide composite nano material by one-step hydrothermal synthesis, wherein the mass ratio of the graphene nano sheet to the molybdenum disulfide in the composite material is 1:2-4:1. The method has the characteristics of mild reaction condition and simple process. The synthesized graphene nano sheet/molybdenum disulfide composite nano material serving as an electrochemical lithium storage and electrochemical magnesium storage electrode material has wide application.

The invention discloses a graphene-supported cobaltosic oxide nano composite material and a preparation method thereof. The graphene-supported cobaltosic oxide nano composite material consists of graphene and cobaltosic oxide, wherein the cobaltosic oxide is loaded on graphene nano sheets; the content of the graphene nano sheets is 2 to 95 weight percent, and the thickness of the graphene nano sheets is 0.3 to 50 nanometers; and the particle size of the cobaltosic oxide is 1 to 200 nanometers and the cobaltosic oxide is ball-shaped or flaky. The preparation method comprises: firstly, mixing solution of graphene oxide, a bivalent cobalt salt and a polymer surfactant; and secondly, mixing the solution obtained by the first step with alkaline solution added with an oxidant, stirring the mixed solution or stirring the mixed solution by ultrasonic waves for 0.2 to 5 hours, transferring the mixed solution to a high-temperature reaction kettle, annealing the reaction product at 100 to 250 DEG C for 3 to 30 hours to obtain a product and washing and drying the product to obtain the graphene-supported cobaltosic oxide nano composite material. The size of the cobaltosic oxide is controllable. The reduction of the graphene oxide and the generation of the cobaltosic oxide are accomplished at the same time.

The invention relates to a graphene nanometer sheet-cobaltous oxide composite negative electrode material of a lithium ion battery and a preparation method thereof, and belongs to the technical field of batteries. The negative electrode material consists of graphene nanometer sheets and cobaltous oxide, wherein the graphene nanometer sheets are distributed on cobaltous oxide particles in a staggering way; the mass fraction of the graphene nanometer sheets is 5 to 90 percent; the thickness of the graphene nanometer sheets is 1 to 50 nanometers; and the particle size of the cobaltous oxide is 10 to 500 nanometers. The preparation method comprises the following steps: dispersing graphite oxide in alcohol-water solution or aqueous solution with ultrasound or stirring; adding cobalt salt, alkali and a reducing agent into the mixture and pouring the mixture into a hydrothermal kettle after stirring; performing further sealing and synchronous hydrothermal reaction, washing, filtering and drying to obtain a graphene nanometer sheet-cobaltous oxide composite; and processing the graphene nanometer sheet-cobaltous oxide composite in the protective atmosphere to obtain the graphene nanometer sheet-cobaltous oxide composite negative electrode material. In the invention, when the material is charged or discharged by a current of 200mA/g, the reversible specific capacity of the material can be stabilized in a range of over 900mAh/g.

The invention discloses a compound nano material of graphene and molybdenum disulfide (MoS2) and a preparation method thereof. The compound material is formed by mixing graphene and a MoS2 nano material in a mass ratio of (1 to 1)-(4 to 1). The preparation method comprises the following steps of: preparing an oxidized graphite nano slice from graphite by a chemical oxidization method; then dissolving molybdate into deionized water so as to form 0.02 to 0.07M of solution; adding L-cysteine serving as a sulfur source and a reduction agent, wherein the mass ratio of the L-cysteine to the molybdate is (5 to 1)-(12 to 1); adding the oxidized graphite nano slice into the solution, and ultrasonically treating so that the oxidized graphite nano slice can be fully dispersed in the hydrothermal reaction solution; transferring the mixture into a hydrothermal reaction kettle and sealing; and synthesizing by a one-step hydrothermal method to obtain the compound nano material of graphene and MoS2, wherein the mass ratio of the graphene nano slice to the MoS2 is (1 to 1)-(4 to 1). The method has the characteristics of mild reaction condition and simple process. The compound nano material of graphene and MoS2 synthesized by the method can be widely used as electrode materials of new energy batteries, high-performance national lubricants, catalyst carriers and the like.

The invention discloses a graphene/ stannic oxide nanometer compounding resistance type film gas sensor, which takes ceramics as a basal body. The surface of the ceramic basal body is photo-etched and evaporated with multiple pairs of interdigital gold electrodes, and is coated with gas-sensitive films of graphene and stannic oxide nanometer composite, and the manufactured resistance type film gas sensor has the advantages of simple manufacturing process and low cost. The gas-sensitive film is composed of a grapheme namosheet layer in a three-dimensional nano-structure and stannic oxide crystal particle composite with an orientated growth characteristic, the introduction of the graphene can favorably reduce the resistance of sensor elements, and the formation of the three-dimensional nano-structure can obviously enhance the specific surface area of the composite, thus the absorption and the diffusion of the gas can be promoted so as to greatly enhance the room temperature gas sensitive response sensitivity of elements. The graphene/stannic oxide nanometer compounding resistance type film gas sensor has the characteristics of high response sensitivity to low concentration ammonia, fast response, favorable recovering performanc, capability of carrying out the detection at the room temperature, and the like, which can be widely applied in the agricultural and industrial production process, and the room temperature detection and control of the concentration of ammonia in the atmospheric environment.

The invention provides a graphene modified high-heat-conductivity aluminum-based composite material and a powder metallurgy preparation method thereof. The material comprises reinforced grains and an aluminum substrate, wherein the composite boundary of the reinforced grains and the aluminum substrate contains high-heat-conductivity graphene nanosheets. The method comprises the following steps: (1) soaking the reinforced grains with a strong acid solution, subsequently washing with deionized water till being neutral, drying, and removing the surface impurities, thereby obtaining activated reinforced grains; (2) adding the activated reinforced grains into a graphene dispersion liquid, mechanically stirring or performing ultrasonic dispersion, and wrapping the graphene nanosheets on the surface, thereby preparing the graphene modified reinforced grains; and (3) mixing the graphene modified reinforced grains with the aluminum substrate powder, pressing into blanks, and sintering, thereby preparing the graphene modified high-heat-conductivity aluminum-based composite material. The composite material provided by the invention is good in chemical stability, high in thermal conductivity and can be used as a heat management material of a large-power semiconductor device.

The invention relates to high-thermal conductivity lubricating oil and a preparation method thereof. The lubricating oil contains base oil and fluorinated graphene nanosheets, wherein the weight percent of content of the fluorinated graphene nanosheets is 0.01 to 10.0 %; and the preparation method comprises the steps as follows: firstly, preparing the fluorinated graphene nanosheets; and secondly, preparing the lubricating oil containing the fluorinated graphene nanosheets. The lubricating oil provided by the invention has the advantages of excellent antifriction effect, extremely high heat conduction capability and excellent stability and dispersibility.

The invention provides a preparation method of an electrode material graphene nanometer sheet and an electrode sheet of a super capacitor prepared from the material. An electrode of the super capacitor assembled by using the material has a stable specific capacity up to 164-210 F/g under the current density of 100 mA/g; and a capacity retention ratio is more than 85% when the current density is gradually increased to 2000 mA/g from 1000 mA/g. The preparation of the graphene nano sheet by using a ball milling method has the advantages of simple method, easy operation, high specific capacity, good cycle performance and the like.

The invention discloses a negative electrode material of a Li-ion battery and a preparation method thereof. The negative electrode material is a load-type negative electrode material, i.e. tin dioxide loaded with grapheme nanometer sheet. The negative electrode material has the advantages of higher electron and ion conductivity, large reaction area, large free expansion space, adaptability to various environments with large charge/discharge rate, and can endow the battery with high cycle performance, high specific capacity and quick charge/discharge capability; and the reversible specific capacity of the battery can be kept at a value larger than 600 mAh.g during charge/discharge with a current of 300 mAh.g. The preparation method of the negative electrode material is simple and feasible and suits industrial production.

The present invention discloses multifunctional graphene electrothermal paste, a multifunctional electrothermal film prepared by the same, a preparation method and application. The preparation methodcomprises the following steps that: (1) graphene nanoplatelets are modified by introducing inducible lipidation and cross-linking reaction groups; (2) the modified graphene, a lipidizable and cross-linking reaction emulsion and various kinds of additives are subjected to liquid phase mixing, the above dispersion liquid is induced to undergo in-situ esterification and cross-linking reaction, so that graphene-based homogeneous electrothermal paste can be formed; (3) an electrothermal paste loading matrix is modified, so that the interfacial property of the electrothermal paste and the matrix material can be enhanced; and (4) the graphene electrothermal paste can be combined with different base materials, so that electrothermal products can be prepared. The graphene electrothermal material ofthe invention has the advantages of adjustable resistivity, adjustable use voltage, adjustable heating efficiency, far infrared heating function, flame retardancy, wide application range, high safety, energy-saving performance and the like, and can be applied to home building material manufacturing, human body care, aviation equipment, medical equipment, transportation pipelines, automobiles andother fields.

The invention discloses a lithium ion battery electrode made of graphene/ MoS2 and amorphous carbon and a preparation method thereof. The lithium ion battery electrode is characterized in that the active material of the electrode is a composite nano-material of graphene nano-sheets/ MoS2 graphene nano-sheets and amorphous carbon, and the balance is acetylene black and polyvinylidene fluoride; the mass percentage of each component is: 75-85% of active material of composite nano-material, 5-10%of acetylene black and 10-15% of polyvinylidene fluoride, wherein in the composite nano-material, the mass percentage of the graphene nano-sheets is 4.2-15%, the mass percentage of the MoS2 graphene nano-sheets is 44-65%, and the balance is the amorphous carbon, wherein the mass ratio of the graphene nano-sheets and the MoS2 graphene nano-sheets is 1 to 1-4 to 1. The preparation method of the electrode comprises the following steps of: using graphite as a raw material to prepare graphite oxide nano-sheets with a method of chemical oxidation; in the presence of the graphite oxide nano-sheets, compounding to obtain the composite nano-material of the graphene nano-sheets/ MoS2 graphene nano-sheets and the amorphous carbon in a hydro-thermal way; and finally using the composite nano-material of the graphene nano-sheets/ MoS2 graphene nano-sheets and the amorphous carbon as an electrochemical active material to prepare the electrode. The electrode has high electrochemical lithium intercalating reversible capacity and good stable circulation property and is widely applied to the new generation of lithium ion batteries.

The invention discloses a compound nano material of graphene nano slice and tungsten disulfide (WS2), and a synthesis method and a preparation method thereof. The compound material is formed by mixing graphene and a WS2 nano material in a mass ratio of (1 to 1)-(4 to 1). The preparation method comprises the following steps of: preparing an oxidized graphite nano slice from graphite by a chemical oxidization method; then dissolving tungstic acid into deionized water so as to form 0.02 to 0.07M of solution; adding L-cysteine serving as a sulfur source and a reduction agent, wherein the mass ratio of the L-cysteine to the tungstic acid is (5 to 1)-(12 to 1); adding the oxidized graphite nano slice into the solution, and ultrasonically treating so that the oxidized graphite nano slice can be fully dispersed in the hydrothermal reaction solution; transferring the mixture into a hydrothermal reaction kettle and sealing; and synthesizing by a one-step hydrothermal method to obtain the compound nano material of graphene and WS2, wherein the mass ratio of the graphene nano slice to the WS2 is (1 to 1)-(4 to 1). The method has the characteristics of mild reaction condition and simple process. The compound nano material of graphene and WS2 synthesized by the method can be widely used as electrode materials of new energy batteries, high-performance national lubricants, catalyst carriers and the like.

Composite polymer films or layers have graphene-based nanosheets dispersed in the polymer for the reduction of gas permeability and light transmittance.

A secondary lithium battery having an anode comprising graphene nanosheets doped with a doping element selected from the group consisting of nitrogen, boron, sulfur, phosphorous and combinations thereof. The secondary lithium battery and the anode provide capacity and other performance without degradation during long term charge and discharge cycling.

The invention discloses a graphene nanometer sheet/MoS2 graphene nanometer sheet and amorphous carbon composite material and a preparation method thereof. The composite material is characterized by being composed of the following components in percentage by weight: 4.2-15% of graphene nanometer sheet, 4.2-65% of MoS2 graphene nanometer sheet and the balance of amorphous carbon, wherein the molar ratio of the graphene nanometer sheet to the MoS2 graphene nanometer is (1:1)-(4:1). The preparation method comprises the following steps: preparing graphite into graphite nanometer sheets by a chemical oxidation method; then evenly dispersing the oxidized graphite nanometer sheets into a solution containing molybdate, thioacetamide or thiourea and glucose; obtaining an intermediate product by virtue of hydrothermal reaction; and carrying out heat treatment on the intermediate product at high temperature to obtain the graphene nanometer sheet/ MoS2 graphene nanometer sheet and amorphous carbon composite material. The method disclosed by the invention has the characteristics of moderate reaction condition and simple process. The graphene nanometer sheet/ MoS2 graphene nanometer sheet and amorphous carbon composite material, which is synthetized by the invention, can be widely applied by serving as an electrochemical storage lithium electrode material, an electrochemical storage magnesium electrode material and a catalyst carrier.

A method for producing nanofluids with multilayered graphene nanoplatelets for providing improved heat transfer coolant fluids. A method for optimizing the concentration of nanoplatelets based on their morphology that allows achieving high thermal conductivity and low viscosity thus resulting in high heat transfer coefficient. A method is provided to functionalize as received graphene nanoplatelets by oxidaitively treating the multilayered graphene/nanothin graphite to generate highly dispensable nanoparticles for suspension in polar fluids for cooling thermal sources, such as power electronics and other heat transfer cooling applications.

The invention discloses a method for preparing a G/Sn/PAN-base carbon nanometer fiber membrane. The method for preparing the G/Sn/PAN-base carbon nanometer fiber membrane includes: 1) preparing spinning solution, to be more specific, weighing polyacrylonitrile, nanometer tin powder and graphene nanometer film according to certain mass ratio, blending and dissolving in N-N dimethyl formamide, and stirring to obtain the uniformly dispersed electrostatic spinning solution; b) electrostatic spinning, to be more specific, carrying out electrostatic spinning on the electrostatic spinning solution of the step a) to obtain a graphene/tin/polyacrylonitrile nanometer fiber membrane; c) pre-oxidizing, to be more specific, pre-oxidizing the graphene/tin/polyacrylonitrile nanometer fiber membrane of the step b) in air atmosphere to obtain the pre-oxidized nanometer fiber membrane; d) carbonizing, to be more specific, carbonizing the pre-oxidized nanometer fiber membrane in argon atmosphere to obtain the G/Sn/PAN-base carbon nanometer fiber membrane. The method for preparing the G/Sn/PAN-base carbon nanometer fiber membrane is easy to operate, the graphene coats the nanometer fiber well; the G/Sn/PAN-base carbon nanometer fiber membrane has advantages of large specific surface area, high porosity, and high electrical conductivity and so on, and has broad expanding space.

The invention discloses a high capacity and stable cyclic performance lithium ion battery electrode and a preparation method thereof. The invention is characterized in that: the electrode comprises the following components in percentage by mass: 75 to 85 percent of graphene nano slice/molybdenum disulfide (MoS2) compound nano material serving as an active substance, and 5 to 10 percent of acetylene black and 5 to 15 percent of polyvinylidene fluoride; and the mass ratio of the graphene nano slice to the MoS2 compound nano material in the compound nano material active substance is (1 to 1)-(4 to 1). The preparation method for the electrode comprises the following steps of: preparing an oxidized graphite nano slice by using graphite as a raw material by a chemical oxidization method; synthesizing by a one-step hydrothermal in-situ reduction method in the presence of the oxidized graphite nano slice to obtain a graphene nano slice/MoS2 compound nano material; and finally, preparing the electrode by using the graphene nano slice/MoS2 compound nano material as the active substance. The electrode has high electrochemical lithium storage reversible capacity and cyclic stabilization performance, and can be widely applied to new generation lithium ion batteries.

The invention discloses a grapheme/WS2 nanocomposite electrode of a lithium ion battery and a manufacturing method thereof. The electrode comprise 75-85% of nanocomposite active materials consisting of grapheme nano-sheets and WS2, 5-10% of acetylene black and 10% of polyvinylidene fluoride in percentage by mass, wherein the amount-of-material rate of the grapheme nano-sheets to the WS2 nano materials in the nanocomposite active materials is (1:1)-(4:1). The manufacturing method of the electrode comprises the following steps: using a chemical oxidation method to manufacture graphite oxide nano-sheets by taking graphite as a raw material; under the existence of the graphite oxide nano-sheets, synthesizing by using a hydrothermal in-situ reduction method so as to obtain the grapheme nano-sheets/WS2 nanocomposite; and manufacturing the electrode by taking the grapheme nano-sheets/WS2 nanocomposite as the active material. The electrode has the advantages of high electrochemical lithium storage reversible capacity and stable circulation property, and can be widely applied to next-generation lithium ion batteries.