447 results about "Graphene flake" patented technology

The invention relates to the technical field of packaging of power electronic devices, in particular to a three-dimensional packaged double-sided heat dissipation power module. The structure comprises an upper active metal brazing base material substrate and a lower active metal brazing base material substrate, a plurality of silicon carbide MOSFET chips, conductive strips and an inserter used for fixing the chips are arranged between the upper active metal brazing base material substrate and the lower active metal brazing base material substrate, the upper half-bridge chip is annularly arranged around a direct-current positive terminal, the lower half-bridge chip is annularly arranged around a direct-current negative terminal, and heat dissipation channels are formed in the upper surface and the lower surface of each chip. The impedance of branches is controlled to be equal, the current of each branch chip is balanced, the distance and layout of the chips are optimized, the overall loop area is reduced, the parasitic stray inductance of the module is reduced, in addition, the chips and the substrate are connected in a crimping mode, the chips and the copper columns are in contact through pressure to achieve electric heat conduction, the crimping materials are graphene sheets and molybdenum sheets, and the cost is low. Good contact between the chip and the copper columns is ensured, and contact resistance and thermal resistance are reduced. According to the invention, the effects of improving the heat dissipation efficiency, reducing parasitic stray inductance, balancing the current distribution of the parallel chips, and enhancing the module reliability and the conversion efficiency are achieved.

The invention discloses a calcining carbon removal-supercritical expansion stripping method for regenerating graphene from graphite of a waste lithium battery, and belongs to the field of lithium battery recovery and nano material preparation. Comprising the following steps: treating the waste lithium battery to obtain waste lithium battery positive and negative electrode mixed powder, and then roasting to obtain battery powder; leaching the battery powder in a nitric acid solution to obtain purified graphite slag; the method comprises the following steps: mixing graphite slag with supercritical gas fluid, treating, quickly releasing pressure to normal pressure, and separating to obtain graphene. According to the method, on the basis of interlayer structure characteristics of the waste graphite negative electrode, organic matters and amorphous carbon are removed through multi-stage calcination, a supercritical N2 / CO2 mixed fluid permeation and pressure relief expansion synergistic stripping technology is combined, and low-damage dissociation is achieved through graphite microcracks. According to the method, physical stripping and liquid nitrogen shock cooling strengthening are coupled, and the obtained graphene sheet layer is high in integrity and few in structural defect and can be directly used for manufacturing conductive composite materials and energy storage devices.

The invention relates to the technical field of dispersing agents, and particularly discloses a high-concentration water-based graphene dispersing agent. The high-concentration water-based graphene dispersing agent is prepared from the following raw materials in parts by weight: 25 to 30 parts of a modified nonionic surfactant, 8 to 12 parts of sodium lignin sulfonate, 0.4 to 0.8 part of a de-foaming agent and 90 to 100 parts of de-ionized water, the modified nonionic surfactant is prepared by the following steps: carrying out dehydration esterification reaction on 1-pyrene butyric acid and N-hydroxysuccinimide, carrying out nucleophilic substitution reaction on the obtained product and polyethylene glycol monododecyl ether to obtain modified 1-pyrene butyric acid, and finally polymerizing the modified 1-pyrene butyric acid and n-butyl acrylate. The method is easy to operate, graphene does not need to be subjected to oxidation reduction, the integrity of a graphene sheet layer can be completely kept, and the performance of the graphene can be fully exerted; the prepared graphene dispersing agent realizes efficient dispersing effect, excellent stability and environment-friendly safety characteristics, and provides solid technical support for wide application of graphene in multiple fields.

The invention provides a compressible high-thermal-conductivity graphene thermal interface material and a preparation method thereof. The preparation method comprises the following steps: preparing a graphene oxide film with low structural unit thickness by adopting a centrifugal spin-coating film casting method, performing limited thermal expansion delamination, compounding with polysiloxane, and performing directional lamination to obtain a highly-oriented graphene / organic silicon composite material. And applying shear stress after pressurizing and densifying along the normal direction of the graphene sheet layer, so that the graphene structure unit forms a continuous buckling structure which is high in density and easy to compress. The densification process promotes the interaction among delamination structure units, broadens a phonon transmission channel, inhibits phonon-boundary scattering, enhances the comprehensive heat-conducting property, plays a role in promoting stress transmission among graphene, and ensures the formation of a continuous buckling structure under shear stress. A continuous buckling structure and a relatively low structure unit thickness (llt in the graphene structure unit; and the compression modulus of the densified vertical graphene array is jointly reduced by means of high density, high thermal conductivity and high compressibility of an existing thermal interface material, and the method can be applied to the fields of new energy automobiles, high-power chips, aerospace electronic equipment and the like, and the problem that high density, high thermal conductivity and high compressibility of the existing thermal interface material are difficult to consider at the same time is solved.

The invention provides a lithium metal composite negative electrode, a preparation method thereof and a solid-state battery. The lithium metal composite negative electrode is of a three-layer structure and sequentially comprises a current collector, an active substance layer and a graphene space layer, the active substance layer is a lithium metal and / or lithium alloy layer, and the graphene space layer comprises three-dimensional graphene, lithium salt, a binder and a hydrophilic additive. In the space layer, the three-dimensional graphene is a novel carbon nanomaterial, the excellent characteristics of super-large specific surface area and super-high conductivity of the graphene are maintained, the pi-pi acting force between graphene sheet layers is overcome, the stability of a macrostructure is maintained, and the three-dimensional graphene serves as a space layer material to effectively store lithium ions and regulate and control lithium ion deposition; and the cycle and rate performance of the solid-state battery is improved.

The invention discloses a three-dimensional (SBC-HIE-FDTD) method for efficiently calculating the propagation characteristics of electromagnetic waves in a graphene dispersive medium on the basis of a mixed explicit-implicit finite difference time domain (HIE-FDTD) method and a surface boundary condition (SBC) of the graphene, and the three-dimensional SBC-HIE-FDTD method is used for efficiently calculating the propagation characteristics of the electromagnetic waves in the graphene dispersive medium. According to the three-dimensional SBC-HIE-FDTD method for efficiently calculating the electromagnetic field in the graphene dispersive medium, the advantages of the HIE-FDTD method in thin dielectric layer modeling and the advantages of the SBC method in the aspect of zero-thickness graphene sheet modeling are fused, so that the size of a small grid caused by a graphene sheet or a thin dielectric layer does not limit the time step length any more; compared with other simulation methods based on a graphene structure, the method has the advantages that the calculation efficiency is better, and the method is particularly suitable for analysis and simulation of radio wave propagation characteristics in a terahertz graphene absorber structure.

The invention relates to the technical field of lithium batteries, and discloses a silicon-based composite negative electrode material and a preparation method thereof, a lithium ion battery negative electrode plate and a lithium ion battery. The negative electrode material comprises a matrix, a carbon layer coated on the outer surface of the matrix and a graphene oxide sheet layer coated outside the carbon layer, the substrate is a silicon oxide SiOx, and 0 lt; xlt; 2; the weight ratio of the matrix to the carbon layer to the graphene oxide sheet layer is 1: (0.1-0.2): (0.2-0.3). The silicon oxide SiOx is coated on the substrate by the carbon layer, so that the direct contact between the substrate and an electrolyte can be reduced, the probability of side reaction can be reduced, the formation of a stable SEI interface and a graphene oxide sheet layer is facilitated, and the conductivity and cycling stability of the silicon-based composite negative electrode material can be improved; meanwhile, the lithium ion battery containing the silicon-based composite negative electrode material has a relatively low expansion rate, and the first-cycle coulombic efficiency and the cycle stability of the battery can be effectively improved.

An energy harvesting device is provided. The device includes a patterned graphene sheet arranged on a substrate, wherein the graphene sheet contains channels; a perovskite composition arranged on the graphene sheet, wherein the perovskite composition conforms to the channels of the graphene sheet; and a luminescent material composition or a 2D material composition arranged on the perovskite composition. The device is configured to convert electromagnetic radiation and / or thermal energy to an electrical signal.

The invention relates to an antistatic plastic film and a preparation method thereof, and belongs to the technical field of polymeric membrane materials, the antistatic plastic film is composed of a PET base film and an antistatic coating formed by curing an antistatic coating, the antistatic coating comprises the following components in parts by weight: 100 parts of organic silicon resin, 12-18 parts of an antistatic agent, 0.8-1.1 parts of a dispersing agent, 0.4-0.6 part of a bridging agent, 0.15-0.2 part of a flatting agent and 55-60 parts of a solvent, according to the antistatic agent, lamellar graphene is used as an electrostatic charge release matrix, a silane coupling agent KH-550 is used for introducing amino to the surface of a lamellar layer for modification, methyl chloroacetate and the amino grafted to the lamellar layer are used for substitution, finally, methyl iodide and a substituted amine compound are subjected to quaternization reaction, quaternary ammonium cations are introduced to the surface of the graphene lamellar layer, and the antistatic agent is obtained. And a continuous current collecting layer is formed in the coating, so that the generated electrostatic charge is timely led out, and the film material is endowed with excellent antistatic property.

The invention discloses a silicon carbide / graphene composite material and a preparation method thereof, the composite material is of a three-dimensional network structure generated through in-situ reaction of multilayer graphene and silicon powder, silicon carbide nanowires in the structure are distributed on graphene sheets, the length of the silicon carbide nanowires is 1-5 microns, the diameter of the silicon carbide nanowires is 50-100 nm, and the silicon carbide nanowires are in a beta-SiC crystal form. The material is prepared through a carbon thermal reduction method, specifically, silicon carbide nanowires grow on the surface of graphene in situ, so that electromagnetic parameters and impedance matching characteristics of the material are optimized. The prepared composite material has the characteristics of light weight, high specific surface area, good dielectric loss and the like, and shows good broadband wave-absorbing performance in the frequency band of 2-18 GHz, the minimum reflection loss can reach-23.535 dB, and the effective absorption bandwidth reaches 1.498 GHz. The method is simple in process, low in energy consumption and suitable for large-scale production, and has wide application prospects in the fields of stealth technology, electromagnetic shielding and the like.

The invention provides a lithium iron phosphate positive electrode material and a preparation method thereof, a positive electrode plate, a lithium ion battery and electric equipment, and relates to the technical field of new energy. The lithium iron phosphate positive electrode material disclosed by the invention has a unique secondary particle structure, a graphene conductive skeleton and a carbon coating layer, so that the powder resistance of particles can be greatly reduced, electron transmission in the material is facilitated, and the polarization effect is reduced. According to the preparation method of the lithium iron phosphate positive electrode material, two-fluid spray drying is adopted, graphene sheets already exist in spray solid spheres after spray drying, then carbon coating and nitrogen protection sintering are performed, and spherical lithium iron phosphate secondary particles with a graphene conductive framework and a carbon coating layer are obtained. Compared with the conventional lithium iron phosphate preparation method comprising a crushing step, the lithium iron phosphate preparation method has the advantages that the damage to the carbon coating layer in the crushing process is avoided, and the rate capability of the material is improved.

The invention discloses a graphene microchip dip-coating device for a PCB (Printed Circuit Board) substrate, and relates to the technical field of circuit board processing. Comprising a gantry moving frame, a plurality of treatment grooves and a mounting rod, and a plurality of clamping units distributed at equal intervals are arranged on the mounting rod; the clamping unit comprises a U-shaped frame which is erected on the mounting rod, the U-shaped frame is provided with a fixed clamping frame, the fixed clamping frame is fixedly connected with a positioning block and hinged to a movable clamping frame, and a supporting piece is fixedly connected to the side, close to the positioning block, of the movable clamping frame. The movable clamping frame is supported and limited through the supporting piece, when the base plate is clamped, the base plate only needs to be moved, the supporting piece is pushed through the base plate, the supporting piece relieves limiting of the movable clamping frame through the supporting piece, and then the base plate can be clamped and fixed, so that the step that all clamps are fastened one by one is omitted, and the clamping efficiency is improved. The probability that the substrate deflects during the clamp fastening process is reduced, the operation steps are simplified, and then the dip-coating and electroplating efficiency is improved.

The invention discloses a graphene oxide sheet long-afterglow material and a preparation method and application thereof.The preparation method of the graphene oxide sheet long-afterglow material comprises the steps that a graphite oxide electrode sheet serves as a working electrode, and the working electrode, a counter electrode and a reference electrode are immersed in electrolyte; direct current is applied through an electrochemical workstation, so that the voltage difference between the working electrode and the reference electrode is 1.8-2.0 V, an electrochemical reaction circuit is formed, electrochemical reaction is carried out until the current in a loop where the working electrode and the counter electrode are located is smaller than or equal to 1 mA, the electrochemical reaction is stopped, and the electrolyte is a saturated boric acid aqueous solution. According to the invention, through electrochemical intercalation and oxygen evolution reaction, the graphite oxide electrode plate is stripped from the graphene oxide sheet and is simultaneously compounded with the boric acid crystal in situ, so that the graphene oxide sheet long-afterglow material is directly obtained in one step, and the danger of a traditional method and the redundancy of multi-step preparation are eliminated.

The invention discloses a high-temperature-corrosion-resistant stainless steel gas distribution disc and a preparation method thereof, and relates to the technical field of stainless steel machining, stainless steel is subjected to micro-arc oxidation treatment, the high temperature resistance and wear resistance of the surface of the stainless steel are improved, but the corrosion resistance of the stainless steel subjected to micropore treatment needs to be improved. Stainless steel subjected to micro-arc oxidation treatment is subjected to titanium dioxide layer plating treatment, micro-arc oxidation holes provide additional anchoring points, titanium dioxide layer plating treatment is carried out on the basis, the corrosion resistance of the stainless steel is improved, micro-arc oxidation treatment is firstly carried out on the surface of the stainless steel, then titanium dioxide is plated on the surface of the stainless steel, and the corrosion resistance of the stainless steel is improved. And the binding force between the titanium dioxide layer and the stainless steel substrate can be obviously improved. The graphene oxide-titanium dioxide composite sol is added into the electroplating solution, invasion of corrosive media is effectively blocked, the diffusion path of the corrosive media is prolonged through the graphene sheet layer, and the corrosion resistance of the stainless steel is further improved.

The invention discloses a double-layer structure composite material with rapid photo-thermal response and high anisotropic heat conductivity ratio and a preparation method and application thereof.Graphene sheets and thermoplastic polyurethane are compounded, a melt blending processing technology is combined, and a double-nozzle FDM 3D printing technology is utilized; and the high-heat-conductivity graphene-polyurethane layer is combined with the heat-insulating pure polyurethane layer to form an anisotropic heat conduction structure. The'heat conduction-heat insulation 'double-layer design has originality in the field of heat management, and the problem that efficient heat conduction and heat retention are difficult to consider by traditional materials is solved. The unique electronic energy band structure of the graphene enables the graphene to effectively absorb light energy in a wide spectral range, so that the prepared material can realize efficient and rapid photothermal conversion. In addition, compared with a traditional material processing mode, the FDM 3D printing technology has the advantages of being low in cost, easy to operate, diversified in material, free in design degree and the like, is suitable for large-scale industrial production and has wide application prospects.

The invention discloses a preparation method of chromium-free fingerprint-resistant liquid for an aluminized zinc plate, and relates to the technical field of metal surface treatment materials.The preparation method comprises the steps that a benzotriazole-cerium molybdate composite corrosion inhibition system is constructed, and multiple layers of adsorption films are formed through intermolecular pi-pi accumulation and rare earth ion coordination; meanwhile, a graphene oxide / nano silicon dioxide synergistic enhancement system is introduced, graphene sheet layers are directionally arranged to form a physical barrier, and micropores are filled with nano particles to improve compactness; and meanwhile, a lanthanide rare earth compound is adopted for modifying the flash-rust inhibitor, the stability of a passivation film on the metal surface is enhanced through the empty orbital characteristic of rare earth elements, the nanometer material gradient dispersion technology is combined with the ultrasonic-mechanical coupling dispersion technology, filler uniform distribution and interface bonding strengthening are achieved, and the fingerprint resistance, corrosion resistance and the like of the film layer are effectively guaranteed.

The invention discloses an electromagnetic shielding fabric and a preparation method thereof, and relates to the technical field of fabrics. The bismuth ion-doped polyimide is used as an external phase spinning solution, contains a large number of benzene ring structures, has a certain shielding effect on electromagnetism, does not generate radiation crosslinking and chemical degradation reactions after being subjected to high-energy radiation, and has a good electromagnetic shielding effect; then, carboxylated graphene oxide, barium ions and iron ions generate electrostatic adsorption, so that ferrite is loaded on a graphene sheet layer, a synergistic shielding effect is generated, the electromagnetic shielding effect of the fabric is improved, the graphene sheet layer serves as an inner phase, polyimide serves as an outer phase, gel fibers of a core-shell structure are prepared through spinning, a double-layer electromagnetic wave absorption path is constructed, and the electromagnetic shielding effect of the fabric is improved. Then under the reduction action of sodium borohydride, a layer of uniform metal bismuth is formed on the surface of the fiber, the electromagnetic shielding performance of the fabric is improved, then through drying, the gel on the inner layer forms a porous aerogel structure, the pores of the aerogel structure are communicated with the pores of the fiber, and the air permeability of the fabric is improved.

The invention discloses a graphene film / copper hot-pressing composite directional high-thermal-conductivity material as well as a preparation method and application of the graphene film / copper hot-pressing composite directional high-thermal-conductivity material. The preparation method comprises the following steps: punching a graphene film to form a plurality of hole structures; blade-coating copper paste on the surface to form a liquid film; the copper paste comprises copper powder, a coupling agent and an organic phase; stacking a plurality of layers; carrying out hot pressing treatment on the circulating laminated structure; and slicing to obtain the graphene film / copper hot-pressing composite oriented high-thermal-conductivity material. When copper powder particles are embedded into the hole structure, the whole hole structure is filled with the copper powder particles, the copper powder particles can transversely enter gaps between graphene sheet layers, a three-dimensional interlocking structure is formed through the sintering effect, resin contained in the copper paste can be subjected to a carbonization reaction in the glue discharging stage, a carbon skeleton is formed, and therefore the three-dimensional interlocking structure is formed. And the infiltration process between the copper powder and the graphene sheet layer is facilitated, and finally the heat conduction performance and the mechanical performance of the graphene film / copper hot-pressing composite oriented high-heat-conduction material are remarkably improved.

The invention discloses a high-energy-density self-supporting negative electrode, a negative electrode preparation method and a sodium ion battery, and relates to the technical field of sodium ion batteries, the high-energy-density self-supporting negative electrode comprises a plurality of self-supporting current collectors, and substrates of the self-supporting current collectors are composed of carbon nanofibers and graphene sheets; the carbon nanofibers form a three-dimensional network structure through electrostatic spinning; and the graphene sheets are inserted and embedded in the three-dimensional network structure to form a three-dimensional network structure. The negative electrode preparation method and the sodium ion battery are based on a high-energy-density self-supporting negative electrode. According to the preparation method, a three-dimensional network structure is constructed on the high-energy-density self-supporting negative electrode by using the carbon nanofibers and the graphene sheets, so that the adhesion area of the negative electrode substrate is increased, the purposes of increasing the active point locations of the negative electrode and improving the conductivity of the negative electrode are achieved, and a more stable self-supporting negative electrode preparation method can be obtained on the basis; and the sodium ion battery with more stable performance is obtained.

The invention belongs to the technical field of polymer composite materials, and particularly relates to a high-strength bismaleimide resin material and a preparation method thereof. The bismaleimide resin composition comprises the following components in parts by weight: 50-60 parts of bismaleimide resin, 40-50 parts of an allyl compound, 1-3 parts of modified graphene and 0.1-0.5 part of a dispersing filler, the dispersing filler is prepared from modified inorganic nanoparticles and modified tetrapod-like zinc oxide whiskers in a mass ratio of (0.1-1): 1. Wherein the tetrapod-like zinc oxide whiskers can promote the dispersion of the graphene with a large lamellar structure from the macroscopic aspect, so that the graphene is uniformly dispersed in a bismaleimide resin matrix, and the inorganic nanoparticles can play a role in lubrication and isolation, so that the agglomeration among graphene lamellas in a small range is prevented. By adding the graphene composite reinforcing filler, the rigidity of the bismaleimide resin material is improved, and the toughness of the composite material can be improved at the same time.

The invention relates to a molecular dynamics simulation method for constructing graphene fibers by graphene sheets, and belongs to the technical field of graphene material simulation. A simulation model of graphene fibers is constructed by graphene sheets, and a virtual molecular dynamics simulation test is adopted to replace a traditional experimental process, so that the defects of an experiment in time and space scales are overcome. According to the method, through molecular dynamics simulation, the arrangement, combination and curling behaviors of graphene sheets in the fiber are deeply disclosed, and a theoretical basis is provided for optimizing the microstructure and performance of the graphene fiber.

The invention provides a negative pole piece, a secondary battery, an electric device and a hard carbon material.The negative pole piece comprises a negative current collector and a negative film layer located on at least one surface of the negative current collector, the negative film layer comprises the hard carbon material, and the hard carbon material comprises a graphene sheet layer; the space volume H1 between the graphene sheet layers with the interlayer spacing larger than 0.4 nm and the total space volume Htotal between the layers in the graphene sheet layers meet the condition that H1 / Htotal is larger than or equal to 40% and smaller than or equal to 60%. As a result, the dynamic performance and the first coulombic efficiency of the secondary battery can be achieved at the same time.

According to the preparation method of the graphene heat conduction film or the graphene foam, in the preparation process of the graphene heat conduction film or the graphene foam, a porous graphene oxide film with a surface structure in a fluctuating shape is used as a substrate, graphene oxide slurry is used for immersing the substrate, and then the substrate is flatly coated and integrally dried, so that the graphene heat conduction film or the graphene foam is obtained. And then carrying out heat treatment to prepare the graphene heat-conducting film or graphene foam. The arrangement direction of graphene oxide sheets in the porous graphene oxide film is consistent with the direction of the fluctuating surface structure, and after heat treatment, the porous graphene oxide film has a good in-plane heat conductivity coefficient in the surface direction; graphene sheet layer arrangement orientation consistent with the surface direction of the fluctuating morphology of the porous graphene oxide film is reserved in the finally prepared graphene heat conduction film or graphene foam, and a good longitudinal heat conduction channel is provided for the graphene heat conduction film.

The invention is suitable for the technical field of lithium ion battery materials, and discloses a graphene-heteroatom doped porous carbon material, a lithium titanate amorphous carbon coated silicon carbon composite material, a preparation method thereof, a negative pole piece and a lithium ion battery. The graphene-heteroatom doped porous carbon material is prepared from porous carbon, graphene and heteroatoms, the graphene and the heteroatoms are distributed in the porous carbon, and in percentage by mass, the content of the graphene is 0.5 wt%-2wt%, the content of the heteroatoms is 0.5 wt%-2wt%, and the balance is the porous carbon. According to the graphene-heteroatom doped porous carbon material disclosed by the invention, the compaction density of porous carbon is improved by utilizing high electron conductivity of heteroatoms and high ductility of a graphene lamellar structure; in addition, a basic group on the surface of the heteroatom solution and an acidic group of the graphene oxide can generate a chemical bond linked carbon structure through a hydrothermal reaction, and the tap density and the electronic conductivity of the material are improved.

The invention provides a FeCo alloy / graphene foam composite material and preparation and application thereof, the FeCo alloy / graphene foam composite material comprises FeCo alloy particles and graphene foam, and the FeCo alloy particles are loaded on the surface of the graphene foam and embedded between sheet layers and pores of the graphene foam. Different graphene foam contents have great influence on the morphology structure, saturation magnetization intensity, electromagnetic parameters and the like of the product. Along with the increase of the content of the graphene foam, the loading area of the FeCo alloy is continuously increased, and the large-particle FeCo alloy loaded on the graphene sheet is continuously reduced. The saturation magnetization and the magnetic loss capability of the composite material are continuously reduced along with the increase of the content of the graphene foam, and the electrical loss capability is continuously improved.

The invention provides a process for preparing a three-dimensional graphene foam metal composite material by a biological template method. The preparation method comprises the following steps: preparing through an innovative biological template method process, carrying out carbonization-activation treatment on a natural hierarchical porous biological structure serving as a sacrificial template to form a three-dimensional graphene foam skeleton with bionic hierarchical pore channels, and carrying out in-situ compounding of copper / silver metal nanoparticles through a pulse electrodeposition technology to obtain the composite material. And finally, the three-dimensional graphene foam metal composite material with ultrahigh thermal conductivity and eco-friendly characteristics is constructed. The core breakthrough of the heat-conducting property is as follows: a bionic heat transfer framework is optimized, graded pores derived from a biological template form a phonon efficient transfer path, and the axial heat conductivity is improved by more than 40% compared with that of a material prepared by a traditional chemical foaming method; according to graphene-metal interface cooperation, metal nanoparticles directionally grow on the edge of a graphene sheet layer and hole wall defect sites, and interface thermal resistance is reduced to 8.7 * 10 <-9 > m < 2 > K / W by forming a coherent interface; cross-scale heat flow guide control is achieved, specifically, phonon conduction with the in-plane heat conductivity being 1600 W / (m.K) is achieved through a high-crystallinity graphene domain in a micropore, and an electron conduction heat diffusion network is constructed through a metal filling layer in a macropore channel.

The invention discloses a preparation method of a high-elasticity low-thermal-impedance graphene thermal interface material, which comprises the following steps: vertically dripping graphene oxide slurry on a substrate to form a graphene oxide gel array with a pre-oriented structure, and finally depositing the graphene oxide slurry on the surface to obtain the high-elasticity low-thermal-impedance graphene thermal interface material. And drying to obtain a graphene oxide film with certain vertical orientation inside, and carrying out chemical reduction foaming and high-temperature graphitization to obtain the thermal interface material. In the foaming process, oxygen-containing functional groups on the surface of the graphene oxide are converted into gas, graphene sheets are expanded, physical crosslinking is formed at the edge lap joint positions of the graphene sheets due to the pi-pi conjugation effect, and a quadrilateral-like structure is formed. Compared with a horizontally formed graphene film, the material has the advantages that the proportion of the internal graphene sheets arranged along the vertical direction is higher, the horizontal heat conduction capability is improved, better compression resilience is provided, the thermal impedance is reduced, and the material has wide application potential in the field of thermal interface materials.

The invention belongs to the technical field of graphene preparation, and particularly discloses a graphene preparation method and device based on coupling of an ultrasonic phased array and a micro-fluidic chip, and the preparation method comprises the following steps: graphite oxide dispersion liquid enters a micro-fluidic main channel through a sample inlet of the micro-fluidic chip; in a standing wave sound field and a laminar flow state of an ultrasonic phased array, stripping the graphite oxide dispersion liquid through a micro-jet shear force generated by a cavitation effect of the standing wave sound field to obtain a graphene oxide sheet layer; graphene oxide lamellas are synchronously separated to a specified separation flow channel through fluid shear force generated by a micro-channel contraction section and an inertia focusing effect caused by curvature of an arc-shaped separation section, and non-single-layer graphene oxide lamellas are separated to a flow channel. The proportion of the single-layer graphene obtained by the preparation method provided by the invention is as high as 95%, and the problem of microchannel blockage can be relieved.

The present invention discloses a thermal interface material with high compression and resilience and a preparation method thereof. High thermal conductivity fibers and elastic polymers are introduced between the graphene sheets arranged in an oriented manner. Under the action of pressure, the graphene sheets form a curved structure on the surface of the fibers. The elastic polymer firmly binds the graphene and the high thermal conductivity fibers and improves the compression and resilience ability. Physical crosslinking is formed between the curved graphene sheets through π-π conjugation, thereby constructing a material with both a thermal conduction skeleton and an elastic microstructure. Subsequently, it is cut along the direction perpendicular to the graphene sheets to obtain an interface material containing curved graphene sheets and high thermal conductivity fibers, so that the material has both high vertical thermal conductivity, high horizontal thermal conductivity and high compressibility.

This invention relates to the field of graphene preparation technology and provides a method for preparing low-defect graphene powder using a high-temperature molten salt intercalation and instantaneous expansion method. First, a graphite / molten salt composite electrode is prepared. Then, salt is intercalated into the graphite using an electrochemical intercalation method. Finally, the intercalated graphite is exfoliated into thin-layer graphene using a negative pressure high-power microwave exfoliation method or a normal pressure high-temperature quenching exfoliation method. The raw materials used in this invention are low-cost and environmentally friendly, and the production process is safe and efficient. Through the optimized combination of molten salt electro-assisted intercalation technology and the instantaneous expansion method, the prepared graphene not only has a layer count controlled at 3-5 layers and a flake size of 25-300 μm, but also exhibits few defects on the graphene flakes, providing strong technical support for promoting the high-quality development of related industries.