1361results about "Carbon nanotubes" patented technology

The invention belongs to the technical field of conductive carbon paste, and discloses a method for efficiently preparing single-walled carbon nanotube paste, which comprises the following steps of: 1, mixing single-walled carbon nanotube powder with a dispersing agent and a solvent, and dispersing the mixture into uniform carbon nanotube bundle paste in manners of mechanical stirring, emulsifying and the like; and step 2, enabling the uniform carbon nanotube bundle slurry to pass through different micropore channels for multiple times in a high-pressure environment, so that the carbon nanotube bundle slurry is dispersed into uniform single carbon nanotube slurry. Through a special high-pressure homogenizing channel, the adhered and wound single-walled carbon nanotube bundles can be dispersed into the slurry of the single single-walled carbon nanotubes on the premise of ensuring the lengths of the single-walled carbon nanotubes as much as possible. The uniform dispersion is realized, the tube diameter of the single-walled carbon nanotubes is relatively long, and the excellent conductivity of the slurry is ensured by the single single-walled carbon nanotubes and the microcosmic number of the single single-walled carbon nanotubes.

The invention belongs to the field of flow energy storage battery materials, and particularly relates to a multi-dimensional conductive material, a preparation method thereof and application of the multi-dimensional conductive material in an all-vanadium flow battery. Graphite and multi-walled carbon nanotubes are bonded together by adopting a biomass precursor, a carbon base of biomass is converted into graphitized carbon nanotubes through step-by-step pyrolysis, amorphous carbon in the graphite and the original carbon nanotubes is further graphitized, and finally the multi-dimensional conductive material with the carbon nanotubes inserted on a graphite matrix is formed. The multidimensional characteristic of the surface of the multidimensional conductive material is beneficial to formation of a longitudinal conductive path of the bipolar plate and reduction of vertical body resistance of the bipolar plate, and is also beneficial to wetting of epoxy resin among conductive particles and mechanical interlocking of molecular chains of the epoxy resin, so that the mechanical strength of the bipolar plate is improved, the use performance of the bipolar plate is effectively enhanced, and the service life of the bipolar plate is prolonged. The requirement of long-time operation of the flow battery is met, the material cost of the flow battery is relatively reduced, the industrialization of the bipolar plate is powerfully promoted, and the application value is very good.

The utility model belongs to the technical field of preparation of carbon nanotubes, and particularly relates to a carbon nanotube discharging device. The discharging device is arranged at the discharging end of the tubular heating furnace and comprises a collecting bin, and a collecting cavity communicating with a discharging opening of the tubular heating furnace is formed in the collecting bin. An operation opening is formed in the collecting bin, a flexible pipeline is connected to the operation opening, and the operation opening is connected with the near end of the flexible pipeline in a sealed mode; at least one operating rod penetrates through the flexible pipeline and extends into the collecting cavity, and the far end of the flexible pipeline is in sealed connection with the operating rod; a discharging connector is arranged at the bottom of the collecting bin. The collecting bin arranged at the discharging end is beneficial to timely removal of flocculent single-walled carbon nanotubes formed in the growth process, furnace tube blockage is prevented, production continuity is guaranteed, and safety is improved. And a flexible pipeline and an operating rod are arranged on the collecting bin, so that an operator can collect the carbon nanotubes under the condition that the normal operation of the heating furnace is not influenced. The winding roller is beneficial to orderly collection of carbon nanotube floccules.

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 provides a preparation method and application of a carbon nanotube sponge / liquid metal composite material. The preparation method of the carbon nanotube sponge / liquid metal composite material comprises the following steps: 1) preparing a porous carbon nanotube sponge by adopting a chemical vapor deposition method, and removing surface impurities through plasma cleaning to form a hydrophilic oxygen-containing group; 2) placing the liquid metal gallium-indium eutectic in an ethanol solution, and carrying out ultrasonic dispersion to prepare a uniform liquid metal dispersion liquid; 3) immersing the pretreated carbon nanotube sponge into the liquid metal dispersion liquid, and placing in vacuum to realize vacuum-assisted impregnation; and 4) drying the soaked carbon nanotube sponge in a drying oven at 40 DEG C, and compacting the composite material through rolling operation. According to the application of the carbon nanotube sponge / liquid metal composite material in the field of electromagnetic shielding, the conductivity and the electromagnetic shielding effectiveness of the material are remarkably improved, and the carbon nanotube sponge / liquid metal composite material has a wide application prospect.

The invention discloses an ethanol-regulated layered metal oxide, a preparation method thereof and an application of the ethanol-regulated layered metal oxide in preparation of a single-walled carbon nanotube by catalytic cracking of methane, alkali liquor and soluble metal salt containing Fe, Mo, Mg and Al are dropwise added into an alkaline ethanol aqueous solution to form a precipitate, and the ethanol-regulated Fe-Mo / MgAl-LDOs catalyst is obtained after aging, drying and calcining. The catalyst is applied to methane catalytic cracking to prepare the single-walled carbon nanotube. According to the technical scheme, the dispersity of active components in the layered metal oxide is effectively improved, the layered metal oxide has larger specific surface area and pore diameter, but the pore volume is reduced, and the situation that growth of SWCNTs stops due to wall collision in the growth process is effectively avoided.

The invention discloses a method and a device for preparing a single-walled carbon nanotube based on the host-guest interaction of pillararene and metallocene. The method comprises the following steps: enabling a host compound and a guest compound to form a host-guest complex; the host compound comprises pillararene or a derivative thereof, and the guest compound comprises a cyclopentadienyl metal complex or a derivative thereof; the method comprises the following steps: reacting a mixed reaction system containing a host-guest compound and a polymerization inhibitor at a high temperature to obtain nano-scale catalyst particles; and contacting the nano-catalyst particles with a carbon source, and decomposing and growing the carbon source on the surfaces of the nano-catalyst particles to prepare the single-walled carbon nanotubes. The method disclosed by the invention is mainly based on the strong inclusion behavior of the host compound and the guest compound, and by utilizing the compatibility of the host compound, the solubility of the metallocene in an organic solvent is effectively improved, the decomposition time of the metallocene at high temperature is prolonged, and the in-situ controllable preparation of nano-scale catalyst particles is achieved; and furthermore, the yield and the quality of the single-walled carbon nanotubes are improved.

The invention discloses a device and a method for preparing a single-walled carbon nanotube by a thermal plasma CVD (chemical vapor deposition) method, and relates to the technical field of nano carbon material preparation, the device structurally comprises a thermal plasma electric arc furnace, a CVD growth chamber, a cooling chamber and a collecting tank which are sequentially connected in series, the thermal plasma electric arc furnace structurally comprises hollow graphite serving as a cathode, a graphite crucible serving as an anode and a furnace body. The graphite crucible is located on the lower portion of the thermal plasma electric arc furnace, and the hollow graphite is located on the upper portion of the thermal plasma electric arc furnace and above the graphite crucible. According to the device and the method, a two-step continuous growth process is adopted, so that the yield and the quality of the single-walled carbon nanotube are remarkably improved; and meanwhile, the common problems of excessive catalyst, coking short circuit, arc breaking and the like in the process of preparing the single-walled carbon nanotube by a conventional plasma arc method can be effectively avoided through a shallow crucible and a bottom gas inlet mode, so that the continuous stability and the yield of the reaction are greatly improved, and the method is an effective route for large-scale preparation and has important commercial value.

The present invention belongs to the field of liquid flow energy storage battery materials, and particularly relates to a multi-dimensional conductive material, a preparation method thereof, and an application thereof in a vanadium redox flow battery. The present invention uses a biomass precursor to bond graphite and multi-walled carbon nanotubes, and through stepwise pyrolysis, converts the carbon-based biomass into graphitized carbon nanotubes. The amorphous carbon in the graphite and the original carbon nanotubes is also further graphitized, and finally a multi-dimensional conductive material with carbon nanotubes inserted into a graphite matrix is formed. The multi-dimensional characteristics on the surface of the multi-dimensional conductive material are beneficial to forming a longitudinal conductive path on the bipolar plate, reducing the vertical bulk resistance of the bipolar plate, and also facilitating the wetting of epoxy resin between conductive particles and the mechanical interlocking of its molecular chains, improving the mechanical strength of the bipolar plate, effectively enhancing the service performance of the bipolar plate, meeting the requirements of long-term operation of the flow battery, relatively reducing the material cost of the flow battery, strongly promoting the industrialization of the bipolar plate, and having good application value.

A mask-based testing system for detecting a biomarker received from lungs and airways of a test subject includes an exhaled breath condensate (EBC) collector integrated into an inside of a face mask worn by the test subject. The EBC collector converts breath vapor received from the lungs and airways of the test subject into a fluid biosample. A biosensor is fixed to the inside of the face mask for receiving a fluid biosample from the EBC collector and testing the fluid biosample for a target analyte. The biosensor generates a test signal dependent on at least the presence and absence of the target analyte in the fluid biosample. An electronic circuit is fixed to an outside of the mask for receiving the test signal, determining from the test signal a test result signal depending on detecting or not detecting the target analyte, and transmitting the test result signal to a remote receiver.

The invention relates to the field of lithium battery negative electrode materials, and particularly discloses a high-energy silicon-carbon composite negative electrode material for a lithium ion battery and a preparation process of the high-energy silicon-carbon composite negative electrode material. The preparation method comprises the following steps: mixing resin-based activated carbon and biomass activated carbon with specific pore volume and compressive strength according to a mass ratio of 1: (0.2-0.3) to obtain a porous carbon matrix; depositing silicon nanoparticles on the porous carbon substrate by adopting a fluidized bed chemical vapor deposition process; depositing a thin carbon layer on the surface of the silicon-carbon core material by taking acetylene as a carbon source; and carrying out secondary carbon coating by adopting a rotary furnace to form the silicon-carbon negative electrode material. According to the composite negative electrode material prepared by the process, the resin-based activated carbon is used as a main matrix, so that the influence of more impurities and non-uniform pore structure distribution of biomass activated carbon on the cycling stability and conductivity of the silicon-carbon negative electrode material is reduced, and the problems of volume expansion and conductivity of the silicon-based negative electrode material are solved.

The invention provides a silicon-carbon negative electrode material, a preparation method thereof and a secondary battery. The silicon-carbon negative electrode material comprises a carbon skeleton, nano silicon particles and a carbon coating layer, wherein the carbon skeleton is a complex of carbon nanotubes and amorphous carbon. The amorphous carbon has a hierarchical pore structure, and the hierarchical pore structure comprises 65-85% of micropores and 15-35% of mesopores. At least part of the nanometer silicon particles are contained in the grading hole structure, and the carbon framework is coated with the carbon coating layer. The silicon-carbon negative electrode material has a carbon skeleton with a hierarchical pore structure, volume expansion of nano silicon can be effectively relieved, the cycle performance of the material is improved, and a three-dimensional conductive network constructed by the carbon nanotubes is also beneficial to improvement of the rate capability of the material.

The invention discloses a method for preparing a carbon nano tube by rapidly decomposing a waste high-molecular polymer, and belongs to the technical field of nano material preparation. The method comprises the following steps: mixing a waste high-molecular polymer (such as polyethylene, rubber and the like) serving as a carbon source with a metal-based catalyst and a conductive carbon material, sealing the mixture in a reaction container, connecting an external power supply, instantaneously heating to 600-2500 DEG C under the action of current through the Joule heating effect of the conductive carbon material, and reacting for 5-60 seconds to realize the efficient growth of the carbon nanotube. According to the method, the agglomeration of the catalyst is inhibited through the rapid heating and cooling characteristics of Joule heat, the carbon source is promoted to be selectively decomposed into C1-C3 small molecules, and the graphitization degree and diameter uniformity of the carbon nanotubes are remarkably improved. Compared with the traditional method, the method has the advantages of short reaction time (second level), low energy consumption, high product purity, capability of macroscopic preparation and the like, and is suitable for industrial large-scale production.

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 present application discloses a method for preparing ultra-long carbon nanotubes with an ultra-high yield. The method includes setting a substrate in a reactor, introducing a mixed gas 1 into the reactor to displace the air in the reactor with the mixed gas 1, and raising the temperature in the reactor until the reaction temperature is reached. The mixed gas 1 includes hydrogen and an inert atmosphere gas; continuously introducing a mixed gas 2 and a catalyst solution into the reactor to react to obtain ultra-long carbon nanotubes; the mixed gas 2 includes a carbon source gas, hydrogen, the inert atmosphere gas, and water vapor; the catalyst solution includes a catalyst precursor, a promoter, and a solvent. This method for preparing ultra-long carbon nanotubes with an ultra-high yield is called the substrate interception and orientation strategy. This method uses the substrate placed in the tubular furnace to intercept and orient the floating short tubes generated by chemical vapor deposition, which can significantly extend the growth time of the carbon nanotubes and finally grow them into ultra-long carbon nanotubes.

Provided herein are methods of purifying graphite comprising: electrochemically treating graphite comprising an impurity selected from the group consisting of metals, metal oxides, and combinations thereof in the presence of an electrolyte; a portion of the impurities is removed by electrochemical treatment and purified graphite is provided. Also provided are purified graphite provided by such a method, as well as a negative electrode and a battery each comprising the purified graphite.

The utility model belongs to the technical field of preparation of carbon nanotubes, and particularly relates to a tubular heating furnace for preparing carbon nanotubes. The utility model provides a tubular heating furnace for preparing carbon nanotubes. The tubular heating furnace comprises a furnace tube and a heat insulator arranged on the periphery of the furnace tube, one end of the furnace tube is a feeding end, and the other end is a discharging end; a gap is formed between the heat insulator and the outer wall of the furnace tube and is divided into a plurality of heating cavities arranged in the length direction of the furnace tube, so that a plurality of temperature zones are correspondingly formed in the space in the furnace tube; and a heating element and a temperature detection element are arranged in the heating cavity. A plurality of air inlet pipelines are led out of the side wall of the furnace tube in the length direction of the furnace tube, and each air inlet pipeline is communicated with the interior of the furnace tube. Raw material gas is supplied through a multi-point gas inlet pipeline, the utilization rate of a carbon source can be increased, the agglomeration time of catalyst particles can be shortened, and therefore the yield of the single-walled carbon nanotubes is increased.

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.

Provided in the present application are a silicon-carbon negative electrode material, and a preparation method therefor and the use thereof. The negative electrode material comprises a porous carbon substrate, and the porous carbon substrate comprises a carbon layer arranged on the surface thereof; pores of the porous carbon substrate are filled with a silicon-carbon material and a carbon material; and the carbon material comprises carbon nanotubes and graphene, wherein the carbon nanotubes and the graphene are compounded on the surface of the silicon-carbon material particles and / or among the silicon-carbon material particles.

The present invention discloses a size-adjustable carbon nanotube hollow fiber and a continuous preparation method thereof, comprising the following steps: using vinylon filaments as a baseline, coating carbon nanotubes on the surface of the baseline by a physical coating method to obtain a composite fiber; removing the baseline from the composite fiber by a water-soluble method to obtain the size-adjustable carbon nanotube hollow fiber. The present invention uses water-soluble vinylon filaments as a baseline, coating carbon nanotubes on the surface of the baseline, and then removing the baseline by a water-soluble method to obtain the carbon nanotube hollow fiber. The preparation method is simple and can be carried out continuously; the carbon nanotube hollow fiber of the present invention is completely composed of pure carbon nanotubes and has good electrical and mechanical properties; the inner diameter and wall thickness of the carbon nanotube hollow fiber can be adjusted by adjusting the number of baselines and the number of repeated coatings, and removing the baseline by the water-soluble method will not damage the carbon nanotubes.

The invention relates to the technical field of preparation of single-walled carbon nanotubes, in particular to a chemical vapor deposition reactor, an FCCVD reaction device and a batch continuous preparation method of single-walled carbon nanotubes. By optimizing the structure of the reactor, the flow field in the reactor is further optimized, uniform distribution of gas is realized, and in-situ growth of catalyst particles and uniformity of the particle size are maintained. Results of the embodiment show that the reaction process is strengthened through optimization design of the reactor, batch continuous preparation of the single-walled carbon nanotubes can be achieved, the utilization efficiency of the catalyst is greatly improved, the yield of the unit catalyst is greatly improved, and the prepared SWCNT is high in quality.

A composite material comprising carbon nanotubes is described, wherein said composite material does not comprise any carbon nanotube aggregates having a smallest dimension larger than 1 mm. The efficiency of dispersion and anchoring as well as processing capability of the commercially relevant carbon nanotube composites are significantly improved.

A reactor including a vertically oriented vessel with a gas inlet port, a distributor, a feedstock port, and a microwave generator. The reactor is designed to process a carbon feedstock to produce hydrogen gas and a hydrogen deficient carbon product, utilizing a fluidized bed provided with microwave energy. Also disclosed are methods of converting a carbon feedstock, particularly a solid carbon feedstock, into hydrogen gas and a hydrogen deficient carbon product, preferably including carbon nanotubes.

The invention discloses a silicon-carbon composite material as well as a preparation method and application thereof, and belongs to the field of lithium ion batteries. The silicon-carbon composite material comprises carbon fibers and a composite material formed by coating silicon with single-walled carbon nanotubes. The composite material of the single-walled carbon nanotube coated silicon is embedded in the carbon fiber; the single-walled carbon nanotube-coated silicon composite material comprises silicon particles and a single-walled carbon nanotube net-shaped coating layer, the single-walled carbon nanotube net-shaped wrapping layer is tightly wrapped on the outer surfaces of the silicon particles; the single-walled carbon nanotube net-shaped wrapping layer is of a two-dimensional net bag type structure formed by assembling non-tube-bundle type single dispersed oxidized single-walled carbon nanotubes serving as assembling elements. The composite material has excellent electrochemical performance.

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 process for preparing a single-walled carbon nanotube and graphene by stripping a multi-walled carbon nanotube, which is characterized in that a supercritical CO2 fluid circulating system, ultrasonic equipment, a stirrer, an external heating jacket and a slit shearing circulating system are arranged on a coupling reaction kettle in a matched manner; the method comprises the following steps: filling a mixed solution formed by a multi-walled carbon nanotube and an organic solvent into a coupling reaction kettle, closing a feeding valve, starting a stirrer and ultrasonic equipment, and heating; the supercritical CO2 fluid is input until the pressure reaches 30-35 MPa; starting a slit shearing circulating system to perform circulating shearing; recovering CO2 after more than 80% of the multi-walled carbon nanotubes are stripped; and respectively unloading to finish the stripping process. According to the method, mature and low-cost multi-walled carbon nanotubes are used as raw materials, the single-walled carbon nanotubes and graphene are prepared by stripping the multi-walled carbon nanotubes through ultrasonic waves and slit shearing coupled supercritical CO2 fluid, the technological process is short, the production efficiency is high, the product increment is large, and the economic benefit is remarkable.

The invention relates to the technical field of carbon nanotubes, and particularly discloses a purification method of a carbon nanotube. The purification method of the carbon nano tube comprises the following steps: (1) weighing a carbon nano tube crude product and various raw materials, (2) adding the carbon nano tube crude product and a surfactant into deionized water, and carrying out ultrasonic dispersion to obtain a dispersion liquid, (3) carrying out gradient centrifugation on the dispersion liquid, and taking an upper-layer suspension liquid, and (4) mixing hydrochloric acid, nitric acid and the suspension liquid, and treating the carbon nano tube to obtain the carbon nano tube. (5) treating the carbon nano tube by dilute acid, mildly oxidizing the carbon nano tube by using a low-concentration hydrogen peroxide solution, and then placing the carbon nano tube in a magnetic field to adsorb magnetic impurities, (6) carrying out cross-flow filtration by using a polycarbonate microfiltration membrane and collecting the treated carbon nano tube, and (7) annealing the treated carbon nano tube by using inert gas and freeze-drying to obtain the purified carbon nano tube. According to the purification method, the metal catalyst, amorphous carbon and graphite impurities can be efficiently removed, and meanwhile, the integrity of the tube wall of the carbon nano tube is kept.

The present disclosure is directed polymer-free, non-composite densified carbon nanotube (DCN) structures from thin carbon nanotube (CNT) films and methods of making the same. CNT thin films can be cut, folded, stacked and pre-arranged in the form of cylinders, discs, domes, frames, gaskets, jars, rings, sacks, seals and sheets on a smooth reaction vessel surface and subsequently densified with the use of chlorosulfonic acid (HClSO3) at elevated temperatures. The disclosed DCN structures can be used as EMI shielding, lightweight structural and functional components in extreme conditions commonly encountered in space exploration, polar expeditions and military operations, and also as hydrophilic filtration media that resist surface fouling and provide high flux.