723results about "Carbon nanotubes" patented technology

The invention discloses a high-initial-efficiency fast-charge graphite composite material and a preparation method thereof, the composite material is of a core-shell structure, the core is graphite, and the shell is lithium sulfonate / lithium molybdate and an amorphous carbon coating layer thereof; the mass ratio of the shell is 5-15 wt% according to the mass ratio of the composite material being 100%. The preparation method comprises the following steps: adding a molybdenum compound into a solvent to prepare a solution, adding graphite oxide, an inorganic lithium salt and a carbon nanotube conductive solution, reacting for 2-12 hours at the temperature of 50-120 DEG C, filtering, carbonizing filter residues to obtain a lithium molybdate conductive agent coated graphite material, and depositing a lithium sulfonate derivative on the surface of the lithium molybdate conductive agent coated graphite material by an atomization method to obtain the lithium molybdate conductive agent coated graphite material. The electron and ion conductivity of the material can be improved, and the rate and the first efficiency of the material can be improved.

In order to solve the problems that an existing positive electrode material is unstable in structure and low in energy density, the invention provides a positive electrode material and a preparation method thereof, a positive electrode plate and a battery, the positive electrode material comprises lithium cobalt oxide of a layered structure, the chemical formula of the lithium cobalt oxide is Li < 1-alpha-beta > Na < alpha > (Mg < gamma > Ti < delta > Co < 1-gamma-delta >) O2, alpha is smaller than or equal to 0.005, and beta is 0.02-0.05; gamma is equal to 0.002 to 0.004, delta is equal to 0.001 to 0.003, and gamma + delta is equal to 0.003 to 0.006.

The invention relates to the technical field of control systems, and discloses a multi-zone cooperative control method and system for a temperature field of a carbon nanotube CVD growth furnace, and the method comprises the steps: obtaining the real-time temperatures of a plurality of temperature zones, and calculating the temperature deviation of each temperature zone; the actual temperature gradient is calculated, if the change rate of the actual temperature gradient exceeds a preset threshold value, the gradient maintaining deviation is calculated, and otherwise, the gradient maintaining deviation is zero; calculating a gain weight; calculating predictive thermal disturbance compensation amount of each temperature zone; calculating a first control item; the predictive thermal disturbance compensation amount forms a second control item; the gradient feed-forward correction value forms a third control item, and the gradient feed-forward correction value is proportional to the gradient maintenance deviation of the temperature zone; and taking the sum of the first control item, the second control item and the third control item as the power control quantity of the temperature zone. Unification and coordination of local temperature control and overall temperature are realized, a stable thermal environment is provided for growth of the carbon nanotubes, and consistency and uniformity of growth of the carbon nanotubes are improved.

The invention relates to the technical field of lithium battery negative electrode materials, and discloses a preparation method of a lithium battery silicon-carbon composite negative electrode material with high cycle stability, and the preparation method comprises the following steps: carrying out magnesiothermic reduction and acid etching on micron silicon powder and magnesium powder to prepare porous silicon particles; growing carbon nanotubes on the surfaces of the porous silicon particles and in pore channels in situ to construct a three-dimensional conductive network; styrene butadiene rubber and glucose are adopted as a composite carbon source to coat the product, and a composite carbon layer is formed through drying and gradient carbonization; and finally grinding and sieving the carbonized product. According to the preparation method disclosed by the invention, pores are constructed in micron silicon, and the micron silicon is externally coated with the composite carbon layer with flexibility and rigidity, so that the volume expansion of silicon is effectively buffered; the in-situ grown carbon nanotube network provides a stable electron conduction path; the micron-sized substrate reduces the specific surface area of the material and improves the first coulombic efficiency. Therefore, the prepared negative electrode material has high cycling stability and excellent rate capability.

The invention relates to the technical field of lithium ion batteries, in particular to a chromium-molybdenum double-doped lithium iron phosphate material as well as a preparation method and application thereof. The preparation method is used for solving the problems of low capacity, low electronic conductivity and poor cycling stability of the existing lithium iron phosphate material. According to the preparation method, chromium-molybdenum is doped into lithium iron phosphate, and the bond energy of a Cr-O bond and a Mo-O bond is stronger than that of a Fe-O bond, so that the dissolution loss of Fe < 2 + > in long-term circulation is reduced, and the battery capacity and the intrinsic electron conductivity of the material are improved; lithium iron phosphate is coated with nitrogen-doped carbon nanotubes, and nitrogen is doped in graphite crystal lattices of the carbon nanotubes, so that additional free electrons are provided, the intrinsic conductivity is improved, the resistance is reduced, the rate capability is improved, and the cycle life is prolonged; the polyaniline coating layer forms a barrier layer on the surface of the lithium iron phosphate particles, so that the cycle performance and the battery capacity are improved; the three components cooperate to improve the capacity, conductivity, rate capability and cycling stability of the material.

The invention belongs to the technical field of material preparation, and particularly discloses a carbon nanotube purification method which comprises the following steps: mixing a carbon nanotube crude product with a solvent, and then shearing to obtain a pretreated carbon nanotube; and oxidizing the pretreated carbon nano tube, and then performing acid pickling to obtain the purified carbon nano tube. According to the purification method disclosed by the invention, shearing treatment is introduced to mechanically activate the carbon nanotubes, and is combined with subsequent oxidation and pickling processes to efficiently remove impurity carbon in the carbon nanotubes, so that the purification method is simple, remarkable in purification effect and high in purification efficiency, the purity of the carbon nanotubes can be greatly improved, the damage to the structure of the carbon nanotubes is small, and the method is suitable for industrial production. The method is suitable for large-scale industrial production.

The invention discloses a preparation method and application of nickel-cobalt bimetallic phosphide for in-situ growth of nitrogen-doped carbon nanotubes. The preparation method comprises the following steps: preparing a graphene oxide dispersion liquid; sequentially adding a cobalt source, a nickel source, a segmented copolymer, a phosphorus source and a nitrogen source into the graphene oxide dispersion liquid, and uniformly mixing to obtain a mixed solution; drying the mixed solution to obtain a precursor; and annealing the precursor in an inert atmosphere to obtain the product. According to the nitrogen-doped carbon material coated phosphide nano-particle composite material and the preparation method thereof, by regulating and controlling the ratio of Ni to Co, a carbon source grows on graphene in situ to form a carbon nano-tube, nickel-cobalt bimetal phosphide nano-particles are uniformly distributed on a nitrogen-doped carbon material to form the nitrogen-doped carbon material coated phosphide nano-particle composite material, and the nitrogen-doped carbon material coated phosphide nano-particle composite material is used as a modified diaphragm material of a lithium-sulfur battery. The preparation method disclosed by the invention has the advantages of mild reaction conditions and easiness in amplification and regulation, and the prepared composite material has a relatively high specific surface area and can be applied to the field of energy sources, especially the field of lithium-sulfur batteries.

A silicon-carbon composite material, and a preparation method therefor and a use thereof. The silicon-carbon composite material comprises a silicon-carbon composite particle; and the silicon-carbon composite particle comprises a carbon matrix and carbon nanotubes distributed in the carbon matrix, the tubes of the carbon nanotubes containing silicon nanowires.

The invention relates to the technical field of die steel materials, in particular to an injection molding die steel material and a preparation method thereof.The preparation method comprises the following steps that firstly, raw materials including, by weight, 0.3%-0.5% of C, 1.2%-1.5% of Mn, 3.3%-3.5% of Cr, 0.7%-0.9% of Si, 0.4%-0.5% of V, 0.1%-0.2% of Ni, 0.01%-0.03% of B and the balance Fe are weighed; according to the injection mold steel material, C, Mn, Cr, Si and other raw materials are blended, smelted, poured and formed, meanwhile, ultrasonic treatment of a synergistic solution is matched, solid solution, water cooling and tempering improvement treatment are carried out, the operation steps can homogenize the structure, stabilize the structure and optimize the toughness and other performance of a product, finally, homogenization treatment is carried out, and through continuous and coordinated improvement in the process, the product quality is improved. The fracture toughness, thermal conductivity and wear resistance of the obtained product are harmoniously improved, and the product is resistant to different degrees of corrosion stability.

The invention belongs to the technical field of carbon nanotube dispersion, and particularly relates to a preparation method of a water-based single-walled carbon nanotube dispersion liquid. The preparation method comprises the following steps: adding a single-walled carbon nanotube into an organic solvent, uniformly stirring, carrying out dispersion treatment, adding a first surfactant into the obtained pretreated slurry A, uniformly stirring, carrying out ultrasonic dispersion to obtain slurry B, carrying out vacuum filtration on the slurry B, washing, and baking a collected filter cake to obtain the single-walled carbon nanotube composite material. The single-walled carbon nanotube C, a second surfactant and water are subjected to dispersion treatment, and the carbon nanotube adsorption material is obtained. The water-insoluble first surfactant is introduced to form a dry powder intermediate, so that secondary agglomeration is effectively inhibited, efficient and stable dispersion is realized while the structural integrity of the carbon nanotubes is maintained, and the preparation process is simple and suitable for industrial popularization and application.

The application belongs to the field of carbon material preparation, and discloses a preparation method of self-supporting carbon nanotube and graphene hybrid material. The preparation method is as follows: two carbon sources with different carbon contents are added into a mixed solution of ethanol and water to form a suspension; the suspension is sprayed on the surface of a metal sheet, and after drying, the metal sheet is placed in a high-temperature furnace for high-temperature heating in a protective atmosphere; after the high-temperature furnace is cooled, the carbon material is taken off from the metal sheet, and then the carbon material is soaked in an acid solution, and then washed with water and dried to obtain the self-supporting carbon nanotube and graphene hybrid material. The method has the characteristics of simple operation, low cost, good product structure interconnection, and easy controllable macro preparation. The self-supporting carbon nanotube and graphene hybrid material can be used as a positive electrode carrier material of a lithium-sulfur battery.

The application relates to a method for removing conjugated polymer materials on the surface of carbon nanotubes, and belongs to the technical field of nanotube surface molecule removal. The method comprises the following steps: annealing treatment is performed on carbon nanotubes with conjugated polymer materials on the surface under a protective atmosphere, so that carbon-carbon double bonds formed between the main chain of the conjugated polymer materials and the carbon nanotubes during the preparation of the carbon nanotubes are broken, so as to remove part of the conjugated polymer materials; a solvent is used to perform rotary flushing on the carbon nanotubes subjected to the annealing treatment; and the flushed carbon nanotubes are subjected to annealing treatment again under a protective atmosphere. The method can ensure that the carbon-carbon double bonds formed between the main chain of the conjugated polymer materials and the carbon nanotubes during the preparation of the carbon nanotubes are broken, so that the effect of removing the conjugated polymer materials on the surface of the carbon nanotubes is achieved; the conjugated polymer materials on the surface of the carbon nanotubes can be removed completely, and the morphology of the carbon nanotubes is not damaged during the removal process.

Provided is a carbon nanotube that can improve safety and is suitably used for forming an electrode film having good conductivity. Another embodiment provides a carbon nanotube dispersion, an electrode composition, and a secondary battery containing the carbon nanotube. 【Solution means】It is solved by a carbon nanotube that satisfies the following (1) to (5). (1) In the Raman spectrum, when the maximum peak intensity in the range of 1560 to 1600 cm -1 is G, and the maximum peak intensity in the range of 1310 to 1350 cm -1 is D, the G / D ratio is 16 or more and 38 or less. (2) The BET specific surface area is 150 m 2 / g or more and 450 m 2 / g or less. (3) The volume resistivity is 1.0×10 -3 to 9.9×10 -3 Ω·cm. (4) The iron content is 7000 ppm or less. (5) The sulfur content exceeds 0 ppm and is 1600 ppm or less.

The application relates to the technical field of nanomaterial preparation, and particularly discloses a carbon nanotube preparation method based on carbon source and plasma time sequence cooperation and a carbon nanotube. In the gas phase deposition process, carbon source gas is input in a pulse mode, and a pulse type plasma is synchronously applied, wherein the carbon source input pulse and the plasma output pulse are time-differently matched, the carbon source supply window and the plasma action window form a non-fully-synchronized time sequence coupling relationship, the carbon source activation, transportation, deposition and structure reconstruction process are controlled in the time dimension, and meanwhile, the carbon source gas is introduced from a position close to the plasma action area to maintain the pulse opening and closing characteristics. The method can improve the growth selectivity of the carbon nanotube, reduce the defect density, and is suitable for controllable preparation of single-wall carbon nanotubes. The single-wall carbon nanotube with a semiconductor content greater than or equal to 83% can be prepared with high selectivity, and the product has the advantages of few defects, high purity and high yield.

The invention discloses a high-purity and low-damage single-walled carbon nanotube purification method which comprises the following steps: carrying out mechanical shearing treatment on a single-walled carbon nanotube to disperse the single-walled carbon nanotube and open a tube bundle structure to obtain a sheared single-walled carbon nanotube; carrying out pre-oxidation on the sheared single-walled carbon nanotube in a weak oxidizing atmosphere to obtain a pre-oxidized single-walled carbon nanotube; carrying out microwave treatment on the pre-oxidized single-walled carbon nanotube or the acidified single-walled carbon nanotube in an inert atmosphere to obtain a single-walled carbon nanotube subjected to microwave treatment; and acidizing the single-walled carbon nanotube subjected to microwave treatment to obtain the acidized single-walled carbon nanotube. The method is simple in process, mild in condition, easy to amplify and suitable for industrial production. The purity of the obtained single-walled carbon nanotube is higher than 99%, the raman spectrum IG / ID ratio is larger than 150 and higher than that before purification, and the single-walled carbon nanotube is high in structural integrity and suitable for the fields of high-performance composite materials, electronic devices, energy storage and the like.

Preferred embodiments provide a method for fabricating pyrolysed carbon nanostructures, the method comprises at least following steps: Providing a substrate, and then Depositing a polymeric material comprising either compounds with different plasma etch rates or compounds that can mask a plasma etching process, and then Subjecting said polymeric material to a plasma etching process (e.g. oxygen plasma) to form polymeric nanostructures and then Pyrolysing said polymeric nanostructures to form carbon nanostructures.

To provide a carbon nanotube (CNT)-containing powder for an electrode of a power storage device, which can exhibit excellent dispersibility in an electrode mixture of a power storage device, and a method for producing the same, and to provide a composite for an electrode of a power storage device and an electrode mixture paste for a power storage device, which can obtain an electrode for a power storage device having low volume resistivity by using the CNT-containing powder for an electrode, and an electrode for a power storage device and a power storage device using the electrode mixture paste. A CNT-containing powder for an electrode of a power storage device, including a carbon nanotube (CNT) and ethyl cellulose as a dispersant. The dispersant may be attached to the surface of the CNT. The CNT-containing powder for an electrode of a power storage device can be produced by kneading a CNT, a dispersant, and a solvent to prepare a paste-like kneaded product, and then drying the kneaded product to obtain a CNT-containing powder.

The present invention relates to a catalyst for manufacturing carbon nanotubes, and particularly, to a catalyst for manufacturing thin-walled carbon nanotubes, carbon nanotubes produced using the catalyst, a carbon nanotube dispersion, an electrode structure comprising the carbon nanotubes, and a secondary battery comprising the carbon nanotubes.

Methods for catalytically growing carbon nanotubes on carbonaceous substrates and hybrid materials prepared by the methods.

The invention discloses a carbon nanomaterial pretreatment device and a process thereof, and belongs to the technical field of carbon nanomaterial modification and application, the device comprises a pretreatment main body, a roller way conveying mechanism, a sagger and a collecting and releasing dust-free purification area, the roller way conveying mechanism penetrates through the purification area and the pretreatment main body, the pretreatment body is provided with a low-temperature area, a medium-temperature area, a high-temperature area and a cooling area in the material conveying direction, the temperatures of all the temperature areas are independently controlled, an exhaust and detection assembly is arranged, and the roller way conveying speed can be adjusted to control the material retention time. According to the process, carbon nanotubes are fed into a device through dust-free feeding, and the temperatures (300-600 DEG C) of a low-temperature area, a medium-temperature area, a high-temperature area and a cooling area and the protective gas and oxidant atmosphere are accurately regulated and controlled; according to the method, the pretreatment target of'modification but not destruction 'is achieved, the purity, surface activity and dispersity of the carbon nanotubes are synchronously improved, the defect structure is optimized, the specific surface area is increased to 600-1000 m < 2 > / g, and the core performance is remarkably enhanced.

To provide an electromagnetic wave absorbing sheet that has a high absorption rate and is thin. [Solution] An electromagnetic wave absorbing sheet having a dielectric layer, a support layer, and a metal layer, wherein the dielectric layer contains a conductive filler and a binder resin, the support layer is a resin sheet, the electromagnetic wave absorbing sheet absorbs electromagnetic waves with frequencies of 20 to 90 GHz, the absorption rate at the electromagnetic wave absorption peak in the frequency range of 20 to 90 GHz is -20 dB or less, and the total thickness of the dielectric layer and the support layer is 15% or less of the wavelength of the electromagnetic wave absorption peak.

The invention relates to a method for preparing a carbon nanotube by using a fixed bed. The method comprises the following steps: step 1, preparing a molecular sieve loaded FeCo bimetallic catalyst as a catalyst precursor; 2, placing the catalyst precursor in a fixed bed reaction furnace chamber, purging with Ar gas, and heating to 550 DEG C; 3, H2 is introduced into the environment with the temperature of 550 DEG C for reduction treatment, and then the temperature continues to rise to 600 DEG C in the Ar atmosphere; and 4, switching to introduce CO gas as a carbon source for reaction, and cooling to room temperature under the protection of Ar after the reaction is finished, thereby finishing the preparation of the carbon nanotube. By adopting the method, the activity and selectivity of the catalyst reach the optimal synergistic effect by regulating and controlling catalyst components, carrier properties, growth conditions and the like, and compared with the prior art and commercial SG65i carbon tubes, the single-walled carbon nanotubes (SWCNTs) prepared by adopting the method have the advantages that the difficulty in the aspect of (6, 5) chiral structure control is obviously reduced, and the purity is higher.

The invention discloses a flocculent vanadium-doped MoN / CNT composite material and a preparation method and application thereof.The method comprises the steps that 1, ammonium molybdate is added into absolute ethyl alcohol to be dissolved, and a solution A is obtained; 2, adding 2-methylimidazole into deionized water, and dissolving to obtain a solution B; 3, adding the solution A into the solution B, stirring, carrying out suction filtration, separating out a precipitate, and drying to obtain a precursor I; 4, adding the precursor I into deionized water, and stirring to obtain a turbid solution; 5, ammonium metavanadate and polyvinylpyrrolidone are added into absolute ethyl alcohol, and a solution C is obtained; 6, adding the solution C into the turbid solution, stirring, carrying out suction filtration, separating out a precipitate, and drying to obtain a precursor II; 7, performing low-temperature sintering on the precursor II in an argon atmosphere to obtain a precursor III; and 8, mixing the precursor III with urea, and performing high-temperature sintering in an argon atmosphere to obtain the vanadium-doped MoN / CNT composite material which has high energy density and high conductivity and can endow an energy storage device with high rate capability and long cycle life.

This invention provides a bamboo-like carbon nanotube with a heterostructure, its preparation method, and its applications. The preparation method includes: dissolving cobalt nitrate and heteropolyacid in ethanol to obtain a first solution; dissolving dicyandiamide in a mixed solution of ethanol and water to obtain a second solution; mixing phytic acid with the second solution uniformly and performing a polymerization reaction to obtain a third solution; adding the first solution to the third solution to perform a chemically induced self-assembly reaction, washing and drying to obtain a dicyandiamide-heteropolyacid-phytic acid-cobalt ion organic polymer; and calcining to obtain the bamboo-like carbon nanotube with a heterostructure. This method is simple and inexpensive; the Co2P and WN / MoN nanoparticles in the bamboo-like carbon nanotube are uniformly distributed in the carbon matrix, improving the electrochemical performance of the material; the introduction of dicyandiamide and phytic acid enables nitrogen and phosphorus doping of the carbon framework, improving the conductivity of the carbon support; and the resulting product exhibits high capacity and excellent cycle stability as a cathode material for metal-air batteries.

High-surface area carbon nanotubes having targeted, or selective, oxidation levels and / or content on the interior and exterior of the tube walls are claimed. Such carbon nanotubes can have little to no inner tube surface oxidation, or differing amounts and / or types of oxidation between the tubes' inner and outer surfaces. Additionally, such high-surface area carbon nanotubes may have greater lengths and diameters, creating useful mechanical, electrical, and thermal properties.

A method for catalytically growing carbon nanotubes on a carbonaceous substrate, and hybrid materials prepared by the method.

This powder comprises a fibrous carbon having a structure in which cylindrical carbon hexagonal net surfaces are laminated in the fiber thickness direction. The ratio of volume resistivity when the powder is compressed to 0.8 g / cm3 to the volume resistivity when the powder is compressed to 0.6 g / cm3 is not less than 0.545.

This invention relates to the field of carbon nanotube preparation equipment technology, and particularly to a gas heating device, a fluidized bed reactor, and a method for preparing carbon nanotubes. The gas heating device includes a heating tube through which a carrier gas flows, and a heating component for heating the carrier gas is fitted over the heating tube. This invention provides a fluidized bed reactor with a reasonable overall structure, convenient installation, and good practicality and potential for large-scale promotion. Specifically, this invention uses electromagnetic induction to uniformly heat the entire heating tube, thereby rapidly and stably heating the carrier gas to a set temperature, ensuring a uniform temperature field distribution within the reaction chamber, and effectively improving the consistency of carbon nanotube growth and product quality. Furthermore, by eliminating traditional resistance wire heating, problems such as high-temperature aging and burnout of the resistance wire are avoided. The equipment has no easily damaged parts, resulting in a low failure rate, reduced maintenance costs, and a significantly extended service life.

The invention provides a method for recovering tail gas generated in production of carbon nanotubes. The method comprises the following steps: compression: introducing tail gas containing methane and hydrogen into a compressor for pressurization; first-stage separation: the pressurized tail gas is introduced into a first-stage membrane separator for separation, methane and first-stage tail gas are obtained, and the main component of the first-stage tail gas is hydrogen; and second-stage separation: introducing the first-stage tail gas into a second-stage membrane separator for separation to obtain hydrogen and second-stage tail gas containing hydrogen. Through two-stage membrane separation, methane and hydrogen are recovered, the methane separated in the first stage can return to the continuous furnace to be continuously used as a raw material for producing carbon nanotubes, and the hydrogen separated in the second stage can be used for producing trichlorosilane, so that the recovery and utilization of resources can be realized.

NCM electrode particle, which has an interphase layer and a nitrogen-containing carbon layer; the NCM electrode particle is used in an electrode of a solid-state battery or a semi-solid battery; the NCM electrode particle comprises: an NCM particle (lithium nickel manganese cobalt oxide) with a single-crystal structure; The intermediate phase layer is applied to the outer surface of the NCM particle; the NCM particle coated with the intermediate phase layer forms a primary particle; the intermediate phase layer comprises a glass phase layer and several ceramic particles dispersed therein; the intermediate phase layer serves to protect the NCM particle and increases the lithium-ion conductivity; A nitrogen-containing carbon layer is applied to the outside of the primary particle; the NCM electrode particle is formed by the NCM particle, the intermediate phase layer, and the nitrogen-containing carbon layer; the nitrogen-containing carbon layer serves to increase the electrical conductivity of the NCM electrode particle; and where nitrogen-doped carbon molecules in the nitrogen-containing carbon layer increase the electronic conductivity and lithium-ion conductivity of the NCM particles and modify the electrical potential of the NCM particles; the nitrogen-containing carbon layer is formed by calcining a nitrogen-containing polymer material in an inert atmosphere and applied to the outer surface of the primary particle; carbon and nitrogen in the nitrogen-containing carbon layer form conjugated C=N bonds to modify an energy band and thus reduce the energy required to excite electrons into a conduction band, thereby increasing the electrical conductivity.