75 results about "Carbon graphite" patented technology

The invention relates to the technical field of modified carbon graphite materials, and particularly discloses an antioxidant modified carbon graphite material and a preparation method thereof, the antioxidant modified carbon graphite material comprises the following raw materials by weight: 30-34 parts of medium temperature pitch, 4-6 parts of modified silica sol and 10-12 parts of artificial graphite powder; from two aspects, firstly, the aluminum dihydrogen phosphate and the boric acid aqueous solution are added, the aluminum dihydrogen phosphate can promote the asphalt to form a denser and firmer glassy carbon structure during carbonization, and phosphorus pentoxide generated by decomposition of the aluminum dihydrogen phosphate and boron oxide generated by dehydration of boric acid can generate a glass phase with an anti-oxidation effect; secondly, core-shell particles are added, a shell layer of the core-shell structure is an aluminum hydroxide structure generated by hydrolyzing aluminum nitrate nonahydrate, and an inner core is epoxidized nano silicon carbide; through the synergistic effect of the two, the mechanical property and the oxidation resistance of the carbon-graphite material are improved.

The invention discloses a multi-layer coated nano silicon negative electrode material and a preparation method and application thereof. The material is of a core-shell structure with a silicon core, a silicon dioxide middle layer, a hard carbon layer and a soft carbon outer layer. The preparation method comprises the following steps: (1) inner layer coating: generating a silicon dioxide or lithium silicate coating layer on the surface of nano silicon particles or silicon-based composite particles through in-situ oxidation or ectopic coating to form a core-shell structure; (2) middle layer coating: coating the surface of the core-shell structure obtained in the step (1) with a lithium-source-containing hard carbon or porous carbon layer to form composite particles; and (3) outer layer coating: coating the surfaces of the composite particles obtained in the step (2) with soft carbon, graphitized carbon or an organic-inorganic hybrid carbon layer to form three-layer coated nano silicon particles. Through a three-layer synergistic coating structure, the core problems of violent volume expansion, poor conductivity and unstable SEI film of the silicon negative electrode are effectively solved.

The invention relates to the technical field of batteries, and provides a battery monomer, a battery device and a power utilization device.The battery monomer comprises an electrolyte and an electrode assembly, the electrode assembly comprises a positive pole piece and a negative pole piece, and the negative pole piece comprises a negative current collector and a negative active material layer arranged on at least one side of the negative current collector; the negative electrode active material layer comprises carbon-coated graphite, and amorphous carbon is arranged on the surface of the carbon-coated graphite; the electrolyte comprises a solvent, and the solvent comprises linear carboxylic ester; in the first direction, the size of the negative electrode active material layer is larger than 130 mm, and the first direction is parallel to the gravity direction. According to the present invention, the carbon-coated graphite is adopted as the negative electrode active material, and is matched with the electrolyte containing the linear carboxylic ester, such that the problems of electrolyte local aggregation and low heat dissipation efficiency in the high battery cell can be effectively improved so as to prolong the cycle life of the battery monomer.

The application discloses a kind of self-sintering oxidation-resistant carbon graphite sealing materials and preparation method thereof, its method includes: activated agent, catalyst and hexagonal boron nitride are mixed and reacted, after washing, dry modified hexagonal boron nitride is obtained;Subsequently, it is put into mixing kettle, again and molten pitch impregnation kneading, then it is broken and sieved to obtain pitch-coated hexagonal boron nitride powder;Again, it is pressed into shape, and physical pressure semi-carbonization treatment is carried out under inert atmosphere, again it is broken and sieved to obtain green coke coated hexagonal boron nitride powder;Crosslinking agent is dissolved in solvent, then add mesocarbon microbead, heat reaction under inert atmosphere, obtain crosslinking modified mesocarbon microbead;Green coke coated hexagonal boron nitride powder and crosslinking modified mesocarbon microbead are mixed uniformly according to the mass ratio of 5-30:70-95, to obtain pressed powder;The pressed powder is pressed into block, then cold isostatic pressing forming is carried out to obtain green body block;Green body block is calcined, then graphitization treatment is carried out under inert atmosphere, and carbon graphite sealing material is obtained.

The invention relates to a carbon graphite sealing material and a preparation method thereof, and belongs to the technical field of mechanical sealing materials, the sealing material comprises the following components: natural graphite powder and phenolic resin powder, and the mass part ratio of the natural graphite powder to the phenolic resin powder is 1: (0.2-0.4). The hardness of the material is not lower than 70 HSD, and the volume density of the carbon-graphite sealing material is not lower than 1.70 g / cm < 3 >. The sealing material is tested on a pump, and the abrasion loss does not exceed 0.1 mu m after 200 hours. The preparation method of the material comprises the following steps: fully mixing natural graphite powder and phenolic resin powder in a V-shaped mixer, and kneading the obtained mixed powder in a kneading machine to obtain a kneaded paste; and crushing the kneaded paste, carrying out hot press molding, and curing in a drying oven to obtain the carbon-graphite sealing material. The preparation process is simple, the production cost is low, the service performance of the obtained material is greatly improved, and the service life is greatly prolonged.

The utility model belongs to the technical field of carbon graphite shaft sleeve machining, and particularly relates to a carbon graphite shaft sleeve inner hole machining device to solve the technical problems that different positions of the end face of a carbon graphite shaft sleeve cannot be circumferentially clamped, and the stability of circumferential clamping of the carbon graphite shaft sleeve cannot be improved. Comprising a circumferential positioning assembly, a connecting frame, a connecting screw rod, a locking nut, a frame assembly and a circumferential cutting assembly, the circumferential positioning assembly is connected with the connecting frame, the connecting frame is connected with the connecting screw rod, the connecting screw rod is connected with the locking nut, the connecting frame is connected with the frame assembly, and the circumferential cutting assembly is connected with the frame assembly. The distance between the two parallel circumferential positioning assemblies is adjusted along the connecting frame, so that the two parallel circumferential positioning assemblies clamp different positions of the end face of the carbon graphite shaft sleeve in the circumferential direction, and the stability of circumferential clamping of the carbon graphite shaft sleeve is improved.

Provided herein hybrid organic-inorganic redox active materials and related composites, compositions, electrode materials, electrodes electrochemical cells, batteries, methods and systems, which, can be used as to provide high performance cathode active materials in high capacity, high energy density, safe, and long-lasting electrochemical cells and batteries when coupled with Li, Na, K, graphite, lithiated graphite, in situ lithiated graphite, silicon, lithiated silicon, in situ lithiated silicon, silicon-graphite, in situ lithiated silicon-graphite, hard carbon, sodiated hard carbon, graphite-silicone, lithiated graphite-silicon etc. anodes in non-aqueous electrolytes.

The invention discloses a low-temperature lithium ion battery and a preparation method thereof, and relates to the technical field of low-temperature lithium ion batteries, the low-temperature lithium ion battery comprises a positive plate, a negative plate, a diaphragm and an electrolyte, a positive active material coating of the positive plate is titanium and cobalt doped lithium iron phosphate, and a negative active material coating of the negative plate is titanium and cobalt doped lithium iron phosphate; a negative active material coating of the negative plate is made of a hard carbon-graphite mixed material; the preparation method is used for preparing the low-temperature lithium ion battery. Compared with the traditional anode and cathode materials of the lithium iron phosphate lithium ion battery, the anode and cathode materials are improved, the deintercalation rate and migration rate of lithium ions from the anode of the lithium ion battery at low temperature are greatly promoted, and the low-temperature cycle performance of the lithium ion battery is improved.

The application provides a copper interconnection layer and a damascene process method of the copper interconnection layer. The side wall and bottom of a via and a trench for forming a copper interconnection line are formed with a barrier layer, which comprises a metal crystal adhesion layer or a graphene layer. The metal crystal adhesion layer can be a crystal Co layer, a crystal Ru layer or a crystal Os layer. The metal crystal adhesion layer can enhance the adhesion with Cu, effectively inhibit the diffusion of Cu into a dielectric layer and be beneficial to improving the electron migration performance of Cu. The formation of the metal crystal adhesion layer can effectively reduce the total thickness of the barrier layer and a first barrier layer and effectively reduce the resistance of the via. The graphene layer is an amorphous carbon / graphene composite layer. Due to the formation of the graphene layer, the copper interconnection layer has a lower resistivity. The formation of the graphene layer can also effectively reduce the total thickness of the barrier layer or the barrier layer and the first barrier layer and effectively reduce the resistance of the via.

The invention provides a furan resin impregnation method which comprises the following steps: step 1, putting a target carbon graphite material finished product or semi-finished product into an electric heating tank, and boiling with boiling water; step 2, putting the product boiled in the step 1 into a drying box for drying, cooling to a target temperature, and then taking out; step 3, putting the product taken out in the step 2 into an impregnating tank, sealing, and then opening a vacuum pump to vacuumize the impregnating tank; step 4, opening a furan resin communicating valve, pumping furan resin into the impregnating tank in the step 3 by utilizing pressure difference, then closing the furan resin communicating valve, and opening a pressurizing valve to pressurize the interior of the impregnating tank; and step 5, placing the resin-impregnated products in the step 4 in a curing tank in a staggered and layered manner, closing the curing tank, and carrying out pressurized curing treatment.

The utility model relates to a shield pump with an anti-impact bearing sleeve, and solves the problems that a motor is cooled by a medium, a rotor is continuously impacted by the medium, and the impact on a bearing is large in the shield pump. The device comprises a cylindrical pump body, a liquid inlet and a liquid outlet are formed in the two ends of the pump body respectively, a driving motor and an impeller driven by the motor are arranged between the liquid inlet and the liquid outlet, the driving motor comprises a stator and a rotor arranged on the inner side of the stator, a rotor shaft is arranged in the center of the rotor, and bearing sleeves are arranged at the two ends of the rotor shaft. The bearing sleeve is a sliding bearing sleeve made of carbon graphite, the outer side of the bearing sleeve is embedded in the bearing seat, and a plurality of annular buffering pieces are arranged between the outer wall of the bearing sleeve and the bearing seat. According to the shield pump disclosed by the utility model, the shaft end of the rotor shaft adopts the carbon graphite bearing sleeve, and the outer side of the bearing sleeve is provided with the plurality of annular buffer pieces, so that the problem of applicability of the carbon graphite bearing sleeve in the shield pump is solved.

The invention provides a hard carbon-graphite composite negative electrode material for a sodium ion battery and a preparation method thereof, and relates to the technical field of battery materials, the hard carbon-graphite composite negative electrode material comprises the following components by mass: 50-80 parts of graphite core, 15-45 parts of hard carbon shell, 1-5 parts of nano silicate modifier, and 1-3 parts of binder; the composite negative electrode material is of a core-shell composite structure, the graphite core serves as an inner core, the hard carbon shell coats the surface of the graphite core, and a nano silicate modifier forms a gradient buffer layer on a hard carbon-graphite interface; the graphite core is used for providing a high-electron conductive path and structural support; by adopting the core-shell structure, the high conductivity of the graphite core and the high sodium storage capacity of the hard carbon shell are fully cooperated, the defect of a single material is overcome, the volume expansion rate can be reduced to 5% or below through the nano silicate gradient buffer layer, the 2000-time circulation capacity retention rate is higher compared with an unmodified composite material, and meanwhile, the graphite core improves the compaction density and the energy density of the material.

The invention discloses a sulfonated graphene enhanced antioxidant carbon graphite sealing material preparation method, which comprises: (1) carrying out surface treatment on a hexagonal boron nitride nanosheet by using an alkali liquid to obtain a surface hydroxylated hexagonal boron nitride nanosheet; (2) mixing and reacting the surface hydroxylated hexagonal boron nitride nanosheet and sulfonated graphene in a solvent, and collecting a reaction product to obtain mixed powder; (3) mixing the mixed powder, graphite powder and calcined coke aggregate to obtain composite aggregate powder; and (4) adding the composite aggregate powder into a mixing and kneading pot, adding asphalt, performing mixing and kneading treatment, performing sheet rolling and crushing to obtain pressed powder, and performing mold pressing and roasting treatment on the pressed powder to obtain the carbon-graphite sealing material. According to the preparation method, sulfonated graphene and hexagonal boron nitride are used for synergistic modification, so that the problems that antioxidant h-BN additive powder is non-uniformly dispersed in a carbon graphite material, the interface bonding strength of h-BN and a carbon graphite matrix material is poor, and thermal expansion coefficients are mismatched are solved.

The invention discloses an antifriction and wear-resistant composite metal coating material based on MoS2 and a preparation method thereof in the field of metal coatings, double low-friction components are formed through MoS2 and a nitrogen-doped carbon graphite material, low-friction coefficient stability can be achieved, and the antifriction and wear-resistant composite metal coating material is far superior to a traditional metal coating; meanwhile, the metal-metal sulfide composite supporting phase endows the coating with high hardness and high toughness, the wear rate can be controlled and kept at a low level, and the core contradiction that a traditional coating is poor in wear resistance during friction reduction and poor in friction reduction during wear resistance is solved. In the invention, MoS2 is wrapped by a metal phase and nitrogen-doped carbon graphite carbon, contact with water molecules in air can be reduced, antifriction failure caused by generation of MoO3 is avoided, metal sulfide and metal elementary substance have excellent corrosion resistance, a corrosive medium can be prevented from permeating into the coating, and under corrosion-wear coupling working conditions (such as marine equipment and chemical pipelines), the corrosion resistance of the coating is greatly improved. The service life of the coating is longer than that of traditional coatings.

The utility model relates to the technical field of carbon product production, and provides a special carbon-graphite material high-efficiency pressurization mixing and kneading device which comprises a mixing and kneading machine body, a heating layer, a mixing reamer and a liftable gland, and a mixing and kneading machine heat preservation layer is arranged on the outer side wall of the mixing and kneading machine body and the outer side wall of the heating layer. According to the asphalt mixing and kneading machine disclosed by the utility model, air in coke fine powder is reduced through the vacuum-pumping system, the flowing resistance of asphalt is reduced, the penetration of the asphalt in coke pores is enhanced, and the filling degree and the bonding strength of the asphalt are improved. The compactness of the paste is improved by strong mixing and kneading under the action of a gland, and heat generated by friction is beneficial to asphalt flowing and polycondensation reaction, so that the coking value is increased. The S-shaped reamers are different from conventional reamers, cross-linking of the paste is intensified through a unique movement mode, strong convection is achieved, kneading is intensified through extrusion force generated by the included angle between the reamers and the pot wall, and the paste is more uniform.

The application discloses a MoS2-based friction-reducing wear-resistant composite metal coating material and a preparation method thereof in the field of metal coating, and forms a double low-friction component through MoS2 and nitrogen-doped carbon graphite material, so that low friction coefficient stability can be realized, and the low friction coefficient stability is far superior to that of traditional metal coating; meanwhile, the metal-metal sulfide composite support phase gives the coating high hardness and high toughness, and the wear rate can be controlled to remain at a low level, so that the core contradiction that traditional coating is poor in wear resistance while reducing friction or is poor in friction reduction while being wear-resistant is solved. In the application, MoS2 is wrapped by a metal phase and nitrogen-doped carbon graphite carbon, so that the contact with water molecules in the air can be reduced, and the friction reduction failure caused by the generation of MoO3 can be avoided; the metal sulfide and the metal element have excellent corrosion resistance, and can prevent corrosive media from penetrating into the coating, so that the service life of the coating is prolonged compared with that of traditional coating under corrosion-wear coupling conditions (such as marine equipment and chemical pipelines).

The application provides a test method and application for quantifying silicon-carbon and graphite capacity in a mixed electrode, and relates to the technical field of batteries. The test method uses XRD technology to obtain diffraction peak intensity of each phase of graphite in a pure graphite negative electrode sheet, calculates specific capacity constants corresponding to each phase of graphite according to the relationship between the diffraction peak intensity of each phase of graphite and the relative specific capacity of each voltage platform of the pure graphite negative electrode sheet, then obtains the diffraction peak intensity of each phase of graphite in a silicon-carbon / graphite mixed negative electrode sheet through XRD, combines the calculated specific capacity constants corresponding to each phase of graphite, measures the real specific capacity contribution of silicon-carbon and graphite under each SOC condition in the mixed negative electrode sheet, and calculates the lithium intercalation amount of the negative electrode material according to theoretical calculation. The test method can be applied to the determination of the silicon-carbon and graphite capacity in silicon-carbon / graphite mixed electrodes with different silicon doping ratios, the test result is real and reliable, continuous and stable, and the test time can be saved.

A blade outer air seal (BOAS) segment of a gas turbine engine includes a support component extending circumferentially in an arc and an arcuate ceramic matrix composite (CMC) sleeve that slides onto the support component. The support component may be made of metal such as a high Nickel (Ni) content alloy or a high Cobalt (Co) content alloy and includes a pair of rails. The CMC sleeve can be formed of a plurality of stacked plies to have a uniform thickness, and include arcuate upstream and downstream curves to engage the pair of rails. The CMC sleeve can be uniformly densified and maintain a uniform thermal gradient. A flexible insulation blanket formed of carbon / graphite felt may be disposed between the rails of the support component and the CMC sleeve to avoid the need to cool the support component.

The utility model belongs to the technical field of carbon graphite shaft sleeves, particularly relates to a carbon graphite shaft sleeve chamfering device, and aims to solve the technical problem that round corner processing of a carbon graphite shaft sleeve cannot be realized. Comprising an installation platform, a limiting sliding lug plate, a lug plate open groove, a first sliding column, a sliding support, a thread fit casing pipe, a driving thread sleeve, a tip cone, an inner end spring, a first sliding groove, a second sliding groove, a clamping plate, a rectangular sliding block, a middle end sliding column, a first limiting block and a second limiting block, the limiting sliding lug plate is fixedly installed on the installation platform, and the lug plate open groove is formed in the limiting sliding lug plate; a first sliding column is slidably mounted in the open groove of the lug plate and locked through a first locking nut, a rectangular sliding groove is formed in the mounting platform, a first sliding plate is slidably mounted in the rectangular sliding groove, and the threaded sleeve is driven to be in threaded fit with the sleeve, so that the tip cone is separated from the carbon graphite shaft sleeve and rotates along with the rotating support plate. And the other end of the carbon graphite shaft sleeve is in contact with the polishing cone, so that the end part of the carbon graphite shaft sleeve is rounded or chamfered.

The application discloses a carbon graphite product pressing control system and method based on multi-parameter cooperation, relates to the graphite pressing control technical field, and sets initial process parameters for each processing link by using a process parameter setting unit, adopts a real-time monitoring unit and a feedback compensation unit, establishes a feedback mechanism for adjusting the initial process parameters by using real-time data, realizes first-stage adjustment of the process parameters, adjusts other parameters by using the correlation between different process parameters in a single processing link through a process parameter adjustment unit, realizes second-stage adjustment of the process parameters, and finally adjusts the process parameters of subsequent processing links by using real-time process parameters of previous processing links through a process parameter coupling unit, and completes third-stage adjustment of the process parameters. The application realizes optimization of the graphite product pressing process by establishing a three-stage adjustment mechanism for the process parameters, so that the quality of the graphite product is improved.

The application discloses a kind of high specific capacity, high rate of biomass-based hard carbon negative material and its preparation method and application.The method is: by hot-pressing method, lignocellulosic biomass is pretreated, then carbonization is carried out under protective gas atmosphere, and hard carbon material is obtained.The hot-pressing method pretreatment process used in the application can make part of hemicellulose decompose, obtain precursor rich in lignin and cellulose, so as to improve the thermal stability of the material.In this process, lignin can effectively inhibit the rapid concentrated pyrolysis of cellulose, and weaken the rearrangement of its pyrolysis products.This not only helps to prevent the excessive growth of hard carbon graphite microcrystal during high-temperature carbonization, but also promotes the generation of small-size closed pore structure, thereby optimizing the microstructure of hard carbon material.The hard carbon material applied to sodium-ion battery negative electrode shows high specific capacity and excellent rate performance.The method has the advantages of simple operation, low equipment requirement, no need to add chemical reagent, green environmental protection and the like.

This invention relates to the field of battery technology, and in particular to a graphite anode material, its preparation method, and a secondary battery. The graphite anode material of this invention comprises multiple secondary graphite particles, each secondary particle comprising multiple primary graphite particles. The surface of each primary graphite particle is coated with a hard carbon layer, and each primary graphite particle has at least one pore containing hard carbon. The preparation method of the graphite anode material includes the following steps: granulating and graphitizing a mixture containing raw material coke and a hard carbon precursor sequentially to obtain the graphite anode material. In the graphite anode material of this invention, the hard carbon not only coats the surface of the primary graphite particles, forming secondary particles, but also penetrates into the interior of the primary graphite particles. The high disordered structure of the hard carbon is more conducive to lithium-ion intercalation. This graphite anode material exhibits excellent rate performance, initial charge-discharge efficiency, and cycle performance.

An aqueous anode composition including metal particles or fibres or carbon graphite particles or fibres, and a binding agent including at least one water-soluble polymer P prepared on the basis of (meth)acrylic acid and (meth)acrylate. A method for producing an anode including said aqueous composition.

The application discloses a preparation method of modified coal pitch and a preparation method of carbon material. The preparation method of modified coal pitch comprises the following steps: mixing a plasticizing agent, a synergist and an additive, then adding coal pitch, stirring, heating to 140-160 DEG C, and constant temperature reaction, so that the modified coal pitch is obtained; the plasticizing agent comprises dibutyl phthalate and / or dioctyl phthalate; the synergist comprises one or more of light oil, naphthalene oil, wash oil, phenol oil and anthracene oil; and the additive comprises carboxymethyl cellulose and / or sodium polyacrylate. The application can significantly improve the wettability of the binder coal pitch to the aggregate without reducing the coking value of the coal pitch, makes the modified coal pitch more evenly distributed among the aggregate, and makes the obtained carbon graphite material have lower porosity, higher bulk density and more excellent electrical and mechanical properties, and the carbon graphite material has excellent thermal stability and structural integrity under high-temperature working conditions.

Disclosed is a manufacturing method for a ternary alloy material comprising nickel, carbon, and graphene. The manufacturing method for the corresponding material is as follows: A conductive material is subjected to the steps of ultrasonic cleaning, sulfuric acid activation, and washing, and then is put into a nickel-carbon-graphene alloy electrolyte to start electrolysis, followed by washing with pure water and drying. Afterwards, through a high-temperature heating conductive carbonization treatment,a ternary alloy material comprising nickel, carbon, and graphene, of 50-100 micrometers is obtained. The ternary alloy material of the present invention is mainly applied to high-quality electromagnetic shielding and absorbing materials and to the reduction of electric arc generation of a large contact terminal, and a product manufactured by the process of the present invention has excellent electromagnetic shielding and absorbance performance and heat dissipation performance, and thus the performance of the product may be improved in a well-balanced manner.

The utility model discloses a cutting device for processing a carbon graphite sealing ring, which belongs to the technical field of carbon graphite sealing ring processing and comprises a bottom plate for supporting and fixing, a fixing plate is mounted on the upper wall of the bottom plate, a cutting driving component is mounted at the upper end of the fixing plate, and a fixing component is further mounted on the upper wall of the bottom plate. The fixing assembly is arranged at the lower end of the driving cutting assembly, and an elastic bearing piece is installed at the lower end of the fixing assembly and arranged at the upper end of the bottom plate. An inflation pipe is externally connected, the ventilation pipe is inflated through an inflation pump, gas in the ventilation pipe enters the first ventilation cavity and the second ventilation cavity, the first elastic bag and the second elastic bag bulge, and one end of the graphite ring can be fixed; the fixed bag-shaped piece is filled with gas, the push rod drives the fixed bag-shaped piece to be inserted into one end of the graphite ring, the gas in the fixed bag-shaped piece is extruded till the fixed bag-shaped piece completely stretches into the graphite ring, and the other end of the graphite ring is fixed.

The invention belongs to the field of production of carbon products, and particularly relates to a preparation method of a carbon-graphite mechanical sealing material, which comprises the following steps: grinding and proportioning raw materials: crushing petroleum coke and pitch coke aggregate coke, grinding into fine powder with D50 of 5-15 mu m by adopting a vertical mill, and grinding into powder with the particle size of 2-5 mu m; the preheating machine, the hot mixing machine and the cold mixing machine are adopted for conducting preheating, hot mixing and cold mixing operation respectively, and pressing of green bodies is conducted through cold isostatic pressing. Compared with a traditional single mixing and kneading mode, key parameters such as temperature and time of each stage can be controlled more accurately. For example, in the preheating stage, the dry material is preheated to 150-250 DEG C and is subjected to temperature equalization for 10-60 minutes, so that a good initial condition is created for subsequent hot mixing, the dry material can be more quickly and uniformly fused with liquid adhesive asphalt in the hot mixing stage, and the paste material is ensured to be fully mixed and kneaded; compared with traditional compression molding, the pressing pressure of cold isostatic pressing is higher, a more compact product structure can be obtained, and therefore higher product performance is obtained.

The invention relates to a silicon carbon / graphite composite material, a preparation method thereof, a negative electrode and a battery. The silicon-carbon / graphite composite negative electrode material comprises a silicon-carbon composite material and a surface modified graphite material, the surface of the surface modified graphite material has a hierarchical pore structure, the pore diameter of the hierarchical pore structure is in bimodal distribution, the hierarchical pore structure comprises micron pores and nano pores, the pore diameter distribution peak value of the micron pores is D, D is 0.5-3 [mu] m, and the pore diameter distribution peak value of the nano pores is 0.5-3 [mu] m. The pore size distribution peak value of the nanopores is 2nm to 50nm; the micron pores are at least partially filled with the silicon-carbon composite material, the particle size of the silicon-carbon composite material is d, and the particle size d of the silicon-carbon composite material and the pore size distribution peak value D of the micron pores of the graphite material meet the following relation: 1: 2 < = d / D < = 1: 1.2. According to the scheme provided by the invention, the energy density, the low-temperature performance and the cycle life can be synergistically improved.

The application provides a silicon-carbon-graphite negative electrode active material, a negative electrode material and application thereof, and the silicon-carbon-graphite negative electrode active material comprises spherical silicon-carbon material and fast-charging artificial graphite. The silicon-carbon-graphite negative electrode active material contains the spherical silicon-carbon material, on the one hand, the spherical silicon-carbon material improves the energy density of the negative electrode active material, and on the other hand, the spherical silicon-carbon material has a spherical shape, the spherical silicon-carbon material can improve the compression resistance, and the spherical silicon-carbon material and the fast-charging artificial graphite have a synergistic effect, so that the silicon-carbon-graphite negative electrode active material composed of the spherical silicon-carbon material and the fast-charging artificial graphite has high compression resistance, thereby greatly improving the compaction density of the negative electrode sheet prepared from the silicon-carbon-graphite negative electrode active material, and enabling the negative electrode sheet to exhibit more excellent long-cycle low-expansion performance under the same compaction; therefore, the silicon-carbon-graphite negative electrode active material has excellent expansion inhibition performance while improving the energy density.

The invention relates to the field of carbon materials, in particular to a carbon graphite material and a preparation method and application thereof. The invention provides a preparation method of a carbon graphite material, which comprises the following steps: S1, mixing carbon aggregate and a first coupling agent for reaction, and drying to obtain modified aggregate; s2, mixing and kneading the modified aggregate, a second coupling agent and a binder to obtain a paste material; s3, after the paste material is cooled, crushing, sieving, compression molding and roasting are conducted, and the carbon-graphite material is obtained. Through two-step chemical grafting, the boric acid ester coupling agent is utilized, chemical bonding is formed between the carbon aggregate and the binder through chemical bonds, in-situ fixation of the boron element is achieved, high-temperature graphitization is not needed, after roasting, the boron element and carbon form a B-C bond, the B-C bond stably exists in the material, and the oxidation resistance is good.