1091 results about "Graphite composite" patented technology

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

The invention relates to an inorganic hydrated salt expanded graphite composite phase-changing heat storage material. In the preparation method thereof, 85-89 mass parts of inorganic hydrated salt sodium acetate trihydrate as a heat storage matrix, 5.5-6.5 mass parts of disodium hydrogenphosphate as a nucleating agent, 2.5-3.5 mass parts of carboxymethyl cellulose as a thickening agent, and 3-4.5 mass parts of expanded graphite is blended in an inorganic hydrated salt mixture as a material with a high thermal conductivity. Due to the use of the expanded graphite, the material not only maintains excellent properties of natural flake graphite such as good thermal conductivity, no toxicity and the like, but also has adsorbability which the natural flake graphite does not have. The invention solves the problems of sub-cooling degree, phase stratification and low thermal conductivity during the heat storage process. The composite phase-changing material has a low sub-cooling degree after the phase changing performance is improved, the solution thereof is uniform without sedimentation and stratification during the solid-liquid phase change, the performance is stable, the repeatability of good, and the phase-changing heat storage can be enhanced through improving the thermal conductivity of the material.

The invention may be practiced to make graphite composites. Preferred composites which may be made in accordance with the invention include conductive polymeric composites (thermally or electrically), paint composites, battery composites, capacitor composites, and pollution abatement catalyst support composites. One method of making the graphite aforementioned composites includes introducing an intercalant into at least one interstice of at least one flake of natural graphite. The method also includes introducing a fluid into the at least one interstices of the flake. Preferably, the fluid comprises at least one of a sub-critical fluid, near critical point fluid, or a supercritical fluid. Furthermore the method includes blending the flake with a polymer, thereby forming a graphite-polymeric composite.

To provide a nonaqueous secondary battery ensuring that a charge-discharge irreversible capacity at an initial cycle is sufficiently small even when an active material layer comprising a negative electrode active material on a current collector is increased in a density for obtaining a high capacity.

This object is attained by a graphite composite particle for a nonaqueous secondary battery, which satisfies the requirements (1) and (2):

• • (1) D_L/D_S is more than 1 and 2 or less, wherein D_L μm means a volume-based median size measured by a laser diffraction/scattering-type particle size distribution measuring apparatus, and D_S μm means an average circle-equivalent particle size which is determined from a measured area S of particles each having a contour not overlapped with a contour of another particle in a SEM; and
  • (2) a Raman R value is 0.04 or more and 0.14 or less, wherein the Raman R value means an intensity ratio I_B/I_A between an intensity I_A of a maximum peak of 1580 cm⁻¹ around and an intensity I_B of a maximum peak of 1360 cm⁻¹ around in a Raman spectrum.

The invention discloses an artificial graphite composite negative electrode material for a lithium ion battery. The negative electrode material is 16-21[mu]m in average grain diameter D50, 1.1-1.2g/cm<3> in tap density, 1.0-3.0m<2>/g in surface specific area, and less than 0.05% in ash content; the preparation method comprises the steps of performing smashing and grading on needle coke to obtain powder of two kinds of granularities; performing uniform mixing on the powder of two kinds of granularities to obtain a composite precursor; performing balling and shaping treatment on the composite precursor; performing high-temperature graphitization treatment on the shaped material; performing uniform mixing on the graphitized material and an organic carbon source; and performing carbonization on the mixture and cooling to the room temperature. The obtained negative electrode material can be 1.75g/cm<3> in compaction density; the initial reversible capacity can be higher than 355mAh/g; the initial discharge efficiency can be as high as 97%; the cycling performance at middle rate (0.5C, 1C, 2C) can be greatly improved; and in addition, the preparation method is simple and low in cost and suitable for industrial production.

An object of the present invention is to provide a graphite film, and a graphite composite film both having an excellent thermal diffusivity which can sufficiently manage heat dissipation of electronic instruments, precision instruments and the like, along with an excellent flex resistance which can withstand application to bent portions.

Means for Resolution of the present invention is a graphite film exhibiting the number of reciprocal foldings being 10,000 times or more as measured using a rectangular strip test piece having a width of 15 mm until the test piece breaks in a MIT folding endurance test under conditions of: a curvature radius R of the bending clamp being 2 mm; a left-and-right bending angle being 135°; a bending rate being 90 times/min; and a load being 0.98 N.

The invention discloses a novel graphite composite grounding material and a preparation method thereof. The novel graphite composite grounding material is in the shape of a rope or stranded wire, and comprises a composite graphite yarn inner core and a composite graphite yarn knitted layer wrapped outside the composite graphite yarn inner core, wherein the composite graphite yarn inner core is a composite graphite yarn bundle composed of a plurality of first composite graphite yarns or a single first composite graphite yarn; each first composite graphite yarn is prepared by twisting a first composite graphite belt; the composite graphite yarn knitted layer is prepared by knitting a second composite graphite yarn; and the second composite graphite yarn is prepared by twisting a second composite graphite belt. The graphite composite grounding material disclosed by the invention has the advantages of corrosion resistance, favorable conductivity, high flexibility, low price, precise soil association and the like, and is easy for transportation; since the price is low, artificial theft destroy can be avoided; and the graphite composite grounding material is suitable for the fields of transformer stations, overhead transmission line towers, tall buildings and all other projects in need of electric grounding.

In an anode material of a lithium-ion secondary battery and its preparation method, a natural graphite, an artificial graphite or both are mixed to form a graphite powder, and the graphite powder is mixed with a resin of a high hard carbon content and processed by a mist spray drying process, and finally added or coated with a special resin material after a carburizing heat treatment takes place to prepare a graphite composite of the anode material of the lithium-ion secondary battery and achieve a smaller surface area of an anode graphite composite of the battery and extended cycle life and capacity.

There is provided an excellent negative-electrode material using graphite for lithium secondary battery that, when used in high electrode density, can yield an excellent lithium secondary battery which has large discharging capacity, achieves high efficiency during charging and discharging, exhibits superior load characteristics, and involves only a small amount of swelling of the electrode during charging. The material has a graphite-composite mixture powder (C) that comprises: a graphite composite powder (A) in which a graphite (D), whose aspect ratio is 1.2 or larger and 4.0 or smaller, is compounded with a graphite (E), which has orientation different from orientation of said graphite (D); and an artificial graphite powder (B).

The present invention discloses an organic matter/expanded graphite composite phase-changing heat-storing building material and the preparation thereof, the method comprises the following procedures: (1) the swelling of the acidic graphite under the function of the microwave to form the expanded graphite with abundant micropore structure; (2) executing blending adsorption to the organic phase-changing material and the expanded graphite at the condition higher than the phase transition temperature, and the organic phase-changing material is adsorbed to the micropore structure of the expanded graphite; (3) the preparing of the organic/expanded graphite composite phase-changing heat storing building material comprising the following steps: (a) the preparing of the heat storing fiber gypsum board, (b) the preparing of the heat storing cement. The method of the invention settles the compatibility of the problem of organic phase-changing material and the building material and the stability. The organic/expanded graphite composite phase-changing heat storing building material has the advantages of low cost, large heat storing density, good heat conducting property and no inflammability.

The invention relates to a preparation method of a high flame retardant polystyrene/expanded graphite composite foaming material. The method comprises the following steps: adding surfaced modified expanded graphite powder with the grain size of 200-500 meshes and nanometer aluminium hydroxide into styrene monomers containing initiating agent and auxiliary agent, stirring evenly, warning up and carrying out prepolymerization; then adding into a water phase in which dispersing agent and suspending agent are dissolved, stirring, mixing and carrying out suspension polymerization at a certain temperature for 4-8hours; adding foaming agent with the weight being 9-11% of the styrene monomers, continuously carrying out polymerization at the temperature above 90 DEG C to obtain foamable composite particles, and carrying out foaming and compression molding on the composite particles to obtain the composite material with favorable heat insulation property and flame retardant property.

The present invention provides a metal-graphite composite material favorable to two-dimensional diffusion of heat and having a high thermal conductivity in two axial directions, and a production method therefor. The metal-graphite composite material of the present invention includes: 20 to 80% by volume of a scaly graphite powder; and a matrix selected from the group consisting of copper, aluminium and alloys thereof, wherein the scaly graphite powder in which a normal vector to a scaly surface thereof is tilted at 20° or higher with respect to a normal vector to a readily heat-conducting surface of the metal-graphite composite material is 15% or less relative to a whole amount of the scaly graphite powder, and the metal-graphite composite material has a relative density of 95% or higher.

The invention belongs to the technical of bituminous pavement maintenance materials, and particularly relates top a cold mixing bituminous concrete and a preparation method thereof. The self temperature adjustment cold mixing bituminous concrete is characterized by being prepared from the following raw mateirals in percentage by weight: 70-80 percent for the aggregate, 1-3 percent for the filler, 5-10 percent for the composite phase change material, 8-10 percent for water and 6-8 percent for the modified emulsified asphalt. The composite phase change material is made of wax and expanded graphite composited together, the mass ratio of the expanded graphite and the wax is 1:8-9, the phase change temperature of the composite phase change material is 40-50 DEG C, and the phase change heat is 150-160kJ/kg. The process is simple, the cost is low and implementation is easy. The concrete has the function of reducing pavement temperature.

The invention discloses a method for preparing a Si/C/graphite composite negative electrode material. The method for preparing the Si/C/graphite composite negative electrode material comprises the following steps that micron silicon and an organic carbon source are evenly mixed, and deionized water or absolute ethyl alcohol is added to the mixture of the micron silicon and the organic carbon source; ball-milling is conducted on the obtained mixture, so that a nanometer silicon mixture which is evenly dispersed is obtained; a natural spherical graphite negative electrode material is obtained and is evenly mixed with the nanometer silicon mixture, deionized water or absolute ethyl alcohol is added to the mixture of the natural spherical graphite negative electrode material and the nanometer silicon mixture, and stirring is conducted; a mixture is obtained after drying, and a spherical particle precursor is obtained; under the nitrogen condition, the precursor is baked, cooled to the room temperature and then is crushed, and then the Si/C/graphite composite negative electrode material is obtained. According to the method for preparing the Si/C/graphite composite negative electrode material, the micron silicon is taken as the raw material, the Si/C/graphite composite negative electrode material high in cycle performance is prepared, the technology is simple and easy to control, and large-scale production of Si/C/graphite composite negative electrode materials can be achieved easily.

The invention belongs to the technical field of material preparation, and particularly relates to a silicon carbide graphite composite material and a preparation method thereof. According to the invention, the preparation raw materials of graphite powder, silicon carbide powder, and a sintering aid are subjected to ball milling mixing, drying, crushing, sieving, and compression molding; after compression molding, degumming treatment and hot pressing sintering are carried out; the sintering process is a temperature-controlled pressure-controlled two-stage pressure-maintaining sintering process; and furnace cooling is performed to obtain the silicon carbide graphite composite material. The method greatly shortens the production period, and improves the product yield; the sintering aid of submicron silicon carbide powder, alumina and yttrium oxide is used for liquid phase sintering under pressure; the high density and low porosity of the product are ensured; the high strength and high wear resistance of the product are improved; no free silicon is contained, which improves the corrosion resistance of the product; temperature increasing and temperature maintaining control are carried out at key sections, which inhibits and eliminates defects of cracks and deformation during sintering. The preparation process is low in time consumption which is 48-72 hours, and the product has high strength, has a bending strength of up to 181 MPa, and has a relative density of up to 95%.

The invention discloses a heat-dissipating method of a power lithium battery, belonging to the technical field of the temperature control of lithium ion battery. In the power lithium battery heat-dissipating method, phase-change materials are filled into a gap inside the lithium ion battery, the phase-change materials are one or two of paraffin/(Al/C) compound material and GMB/graphite compound material, wherein the weight percentage of paraffin and Al/C compound material contained in the paraffin/(Al/C) compound material are respectively 75-100 percent and 0-25 percent, and phase-change points of the paraffin and the Al/C compound material are 15 DEG C-55 DEG C; the weight percentage of GMB and graphite contained in the GMB/graphite compound material are respectively 60-80 percent and 20-40 percent, and phase-change points of the GMB and the graphite are 55 DEG C-65 DEG C. The heat-dissipating method is convenient to operate and maintain, low in cost and used for the heat dissipation of the power lithium battery with high power and fast charge and discharge, has obvious effect and can enhance the working performance and the reliability of the power lithium battery. Experiments show that the heat-dissipating method reduces the temperature rise of the power lithium battery by more than 20 DEG C and has wide application prospect compared with heat-dissipating modes, i.e. the prior battery wind cooling and the like.

The invention discloses a polyamide/graphite composite material with high conduction performance and a preparation method thereof. The composite material consists of a polyamide substrate and nanometer graphite and is prepared through in-situ polymerization. The nanometer graphite has high diameter-to-thickness ratio; and an effective conduction network can be formed in a polymer by using little nanometer graphite. With the low content of a conduction filling of the nanometer graphite, a conduction polymer material keeps original good mechanical performance. The volume conductivity of the polyamide/graphite composite material with high conduction performance can reach 8*10S/cm; and compared with a conventional natural graphite and expanded graphite conductive composite material, the polyamide/graphite composite material has excellent properties of low filling amount and high conductivity.

An electrically conductive laminate composition for fuel cell flow field plate or bipolar plate applications. The laminate composition comprises at least a thin metal sheet having two opposed exterior surfaces and a first exfoliated graphite composite sheet bonded to the first of the two exterior surfaces of the metal sheet wherein the exfoliated graphite composite sheet comprises: (a) expanded or exfoliated graphite and (b) a binder or matrix material to bond the expanded graphite for forming a cohered sheet, wherein the binder or matrix material is between 3% and 60% by weight based on the total weight of the first exfoliated graphite composite sheet. Preferably, the first exfoliated graphite composite sheet further comprises particles of non-expandable graphite or carbon in the amount of between 3% and 60% by weight based on the total weight of the non-expandable particles and the expanded graphite. Further preferably, the laminate comprises a second exfoliated graphite composite sheet bonded to the second surface of the metal sheet to form a three-layer laminate. Surface flow channels and other desired geometric features can be built onto the exterior surfaces of the laminate to form a flow field plate or bipolar plate. The resulting laminate has an exceptionally high thickness-direction conductivity and excellent resistance to gas permeation.

The invention provides a carbon cladding layer expansion graphite composite material used for lithium ion batteries and a preparation method thereof. The carbon cladding layer expansion graphite composite material has a shell-kernel structure, wherein, the inner kernel is phosphorus-doped layer expansion graphite, and the layer spacing is 0.3360-0.3390nm; the outer shell is a pyrolysis product of phenolic resin; the carbon cladding layer expansion graphite composite material is prepared by the processes of raw material pretreatment, oxidized intercalation, cladding and layer removing; phosphoric acid dissolved with organic acid or a phosphate-nitrate system is adopted as oxidized intercalator. Lithium ion battery cathode prepared by the carbon cladding layer expansion graphite composite material of the invention has the characteristics of high capacity, high power and long service life. The preparation method of the invention has the characteristics of simple and easily operated process, and moderate and practical conditions and the like.

The present invention provides preparation process of graphite-base composite material. The preparation process includes the following steps: mixing expandable graphite powder and coke powder and pressing at pressure of 5-50 MPa to form base board with graphite as main component; dissolving asphalt in organic solvent, adding reinforcing material and graphitization catalyzing stuffing, mixing, and eliminating solvent to obtain adhesive mixture; smelting the adhesive mixture at 110-140 deg.c, and soaking the base board at gas pressure of 1-50MPa for 10-120 min; taking out the base board, cooling to room temperature and crushing; and molding the crushed mixture. The graphite-base composite material has excellent electric performance, excellent heat performance, excellent mechanical performance and low cost.