CN111441105B

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Info

Publication number: CN111441105B
Application number: CN202010196347.3A
Authority: CN
Inventors: 徐鸣; 邓泽明
Original assignee: Huazhong University of Science and Technology
Current assignee: Huazhong University of Science and Technology
Priority date: 2020-03-19
Filing date: 2020-03-19
Publication date: 2021-02-26
Anticipated expiration: 2040-03-19
Also published as: CN111441105A

Abstract

Translated fromChinese

本发明属于纳米材料制备相关技术领域，其公开了一种碳纳米管纤维及其制备方法，所述碳纳米管纤维的制备方法包括以下步骤：对阵列碳纳米管材料进行辊压成膜得到阵列碳纳米管薄膜，对超顺排碳纳米管材料进行干法拉膜得到超顺排碳纳米管阵列薄膜；然后，以阵列碳纳米管薄膜作为内芯材料，超顺排碳纳米管阵列薄膜作为壳层材料，将两种薄膜材料堆垛后进行费马扭转得到具有壳芯结构的碳纳米管纤维。按照上述制备方法获得的碳纳米管纤维在各种水性电解液中不发生尺寸变化，且力学拉伸强度高达20～30MPa，在外加扭转作用下，能够产生较大的电容变化，可作为工作电极用于能量回收领域。

The invention belongs to the technical field related to the preparation of nanomaterials, and discloses a carbon nanotube fiber and a preparation method thereof. The preparation method of the carbon nanotube fiber comprises the following steps: rolling an array carbon nanotube material into a film to obtain an array Carbon nanotube film, super-aligned carbon nanotube material is dry-faraded to obtain a super-aligned carbon nanotube array film; then, the arrayed carbon nanotube film is used as the inner core material, and the super-aligned carbon nanotube array film is used as the shell. layer material, the two thin film materials are stacked and then Fermat twisted to obtain carbon nanotube fibers with a shell-core structure. The carbon nanotube fibers obtained according to the above preparation method have no dimensional change in various aqueous electrolytes, and the mechanical tensile strength is as high as 20-30 MPa. Under the action of external torsion, a large capacitance change can be generated, and can be used as a working electrode. Used in the field of energy recovery.

Description

Carbon nanotube fiber and preparation method thereof

Technical Field

The invention belongs to the technical field related to preparation of nano materials, and particularly relates to a carbon nanotube fiber and a preparation method thereof.

Background

In the field of nano materials, carbon nanotube fibers have wide application in the fields of lithium ion batteries, supercapacitors, electric and thermal brakes, tensile strain sensors, energy recovery and the like due to excellent electrical, thermal and mechanical properties thereof. At present, the preparation methods of the carbon nanotube fiber mainly comprise a wet spinning method, a floating catalytic spinning method and an array spinning method. The carbon nanotube fiber is prepared by dispersing the single-arm carbon nanotubes into a spinning solution in wet spinning, but the carbon nanotubes are easy to form tube bundles or twine during dispersion due to the special chemical inertia and the tube-to-tube action of the carbon nanotubes; the floating catalytic spinning method firstly synthesizes carbon nanotubes through catalytic cracking, the obtained carbon nanotubes form an interconnection network, and then the interconnection network is oriented and compacted to form fibers, but the content of the carbon nanotubes is only 95 percent, and the fibers contain more impurities; the key of the array spinning method is to prepare a carbon nano tube array capable of continuously spinning, then twisting, infiltrating and densifying by a solvent to form fibers, wherein the content of the carbon nano tubes is as high as 99.5%, and the carbon nano tube array has ultrahigh length-diameter ratio.

Carbon nanotube fibers have excellent twist-induced capacitance characteristics, yet they must remain structurally stable in solution environments while having good capacitance properties. In addition, the orientation arrangement of the carbon nanotubes in the carbon nanotube fiber can accelerate the conduction of electrons, provide a continuous and ordered transmission path and is beneficial to the migration of electrons/ions. Therefore, the structure of the fiber in the solution is kept stable, and the carbon nano tubes are arranged in an oriented manner, which is the key of good torsion-induced capacitance characteristics. In the method, the carbon nanotube fibers prepared by the wet spinning method have low orientation degree and high density, so that the balance charge quantity absorbed by the carbon nanotube fibers in the electrolyte is small; the carbon nanotube fiber prepared by the floating catalytic spinning method has high impurity content, and the fiber is easy to generate oxidation reduction reaction in electrolyte; the carbon nanotube fiber prepared by the array spinning method has high orientation degree, but the structure of the carbon nanotube fiber is often compact after the carbon nanotube fiber is soaked by a solvent, so that the capacitance performance of the fiber is poor.

Therefore, there is a need in the art for a carbon nanotube fiber with better capacitance and a method for preparing the same.

Disclosure of Invention

The invention provides a carbon nanotube fiber and a preparation method thereof, aiming at overcoming the defects or improving the requirements in the prior art, and aiming at obtaining the carbon nanotube fiber with a shell-core structure by performing Fermat torsion on a stack body of an array carbon nanotube film and a super-ordered carbon nanotube film array, wherein the carbon nanotube fiber has more proper volume density and fiber diameter, does not change the size in various aqueous electrolytes, does not degrade the mechanical tensile strength, and can generate larger capacitance change under the action of external torsion, thereby solving the technical problem of poor capacitance property of the carbon nanotube fiber prepared by the prior art.

In order to achieve the above objects, according to one aspect of the present invention, there is provided a method for preparing a carbon nanotube fiber, comprising the steps of:

rolling the array carbon nanotube material to form a film to obtain an array carbon nanotube film, and performing dry film drawing on the super-ordered carbon nanotube material to obtain a super-ordered carbon nanotube array film; then, the array carbon nanotube film is used as an inner core material, the super-ordered carbon nanotube array film is used as a shell material, and the two film materials are stacked and subjected to Fermat torsion to obtain the carbon nanotube fiber with the shell-core structure.

Further, the arrayed carbon nanotube material is obtained according to the following method: firstly, a catalyst film is deposited on a silicon substrate by utilizing a physical vapor deposition method, then an array carbon nanotube material is grown on the catalyst film of the silicon substrate by utilizing a water-assisted chemical vapor deposition method, and the array carbon nanotube material is stripped from the silicon substrate for use.

Further, in the water-assisted chemical vapor deposition process, the growth temperature of the array carbon nanotube material is 750 ℃, and the carbon source gas C₂H₄The flow rate of (2) was 150sccm, and the growth time was 36 min.

Further, the super-array carbon nanotube material is obtained according to the following method: firstly, a catalyst film is deposited on a silicon substrate by utilizing a physical vapor deposition method, then a super-ordered carbon nanotube array is grown on the catalyst film of the silicon substrate by utilizing a water-assisted chemical vapor deposition method, and the super-ordered carbon nanotube array is stripped from the silicon substrate to obtain a super-ordered carbon nanotube material for later use.

Further, in the water-assisted chemical vapor deposition process, the growth temperature of the super-array carbon nanotube material is 680 ℃, and the carbon source gas C₂H₂The flow rate was 50sccm and the growth time was 20 min.

Further, the array carbon nanotube material comprises 2-wall carbon nanotubes and 3-wall carbon nanotubes, the length of the carbon nanotubes is more than 700 μm, and the density of the carbon nanotubes is 41.3mg/cm³(ii) a The super-array carbon nanotube material comprises 8-wall carbon nanotubes and 9-wall carbon nanotubes, wherein the length of the carbon nanotubes is about 271 mu m, and the density of the carbon nanotubes is 63.1mg/cm³。

In order to achieve the above object, according to another aspect of the present invention, there is provided a carbon nanotube fiber obtained according to the production method as described in any one of the preceding.

Further, the volume density of the carbon nano tube fiber is 180-350 mg/cm³The diameter of the fiber is 0.4-1.2 mm, the mass ratio of the inner core material to the shell material is 1: 1.8-1: 7.2, and the capacitance of the electrochemical double electric layer in a sodium chloride aqueous solution is 8.2-11.36F/g.

Further, the super-array carbon nanotubes of adjacent layers in the carbon nanotube fiber have different orientations.

In general, compared with the prior art, the carbon nanotube fiber and the preparation method thereof provided by the invention have the following beneficial effects:

1. the carbon nano tube has a shell-core structure, in a 0.6M NaCl solution, the specific capacitance of a shell material is about 7F/g, and the specific capacitance of an inner core material is about 21.9F/g, so that the carbon nano tube can store more charges in an electrolyte environment, and under the twisting action, the shell material can extrude the inner core material, thereby reducing the available surface area of electrochemistry to the greatest extent, causing large capacitance change of carbon nano tube fibers, improving electrochemical potential, having better capacitance performance, and in the 0.6M NaCl solution, the electric double layer capacitance of electrochemistry shown by the carbon nano tube fibers is about 9.2F/g.

2. The stack body of the array carbon nanotube film and the super-ordered carbon nanotube film array is subjected to Fermat torsion, and due to the mutual obstruction of the super-ordered carbon nanotube film arrays with different layers, the super-ordered carbon nanotube film arrays on the adjacent layers rotate relatively under the torsion action, the carbon nanotubes in the super-ordered carbon nanotube film arrays are converted into a node contact form from a main line contact form, so that the mutual embedding of the shell layer super-ordered carbon nanotube film arrays is reduced, and the structural recoverability in the carbon nanotube fiber testing process is improved.

3. The super-array carbon nano tubes of adjacent layers have different orientations, so that the wettability of carbon nano tube fibers in a solution is improved, and in addition, the structural stability of the super-array carbon nano tubes in the torsion recovery process is facilitated; the carbon nanotube fiber has no size change in various electrolyte environments, no degradation in mechanical tensile strength, high structural self-sustaining performance and high stability of structure size, and can reach 20-30 MPa.

4. The volume density of the carbon nanotube fiber is 180-350 mg/cm³The diameter of the fiber is 0.4-1.2 mm, the mass ratio of the inner core material to the shell material is 1: 1.8-1: 7.2, the electrochemical double-layer capacitor has a large available surface area, can generate a large electrochemical double-layer capacitor, and has good capacitance performance.

5. The preparation method of the carbon nanotube fiber is simple, easy to implement and high in applicability, and the prepared carbon nanotube fiber has good torsion-induced capacitance characteristics and can be widely applied to the field of energy recovery as a working electrode.

Drawings

FIG. 1 is a schematic flow chart of a method for preparing carbon nanotube fibers according to the present invention;

FIG. 2 is a graph showing electrochemical double layer capacitance curves of carbon nanotube fibers (mass ratio 1:1.8) in a twisted state and an untwisted state, which are manufactured by the method of manufacturing carbon nanotube fibers of FIG. 1;

fig. 3A, 3B and 3C are a torsion density change curve, a voltage curve and a current curve respectively generated when an electrochemical energy recovery device assembled by the carbon nanotube fiber (mass ratio of 1:1.8) prepared by the method for preparing the carbon nanotube fiber in fig. 1 is subjected to torsion.

FIG. 4 is a graph showing electrochemical double layer capacitance curves of carbon nanotube fibers (mass ratio 1:4.2) in a twisted state and an untwisted state, which are manufactured by the method of manufacturing carbon nanotube fibers of FIG. 1;

fig. 5A, 5B and 5C are a torsion density change curve, a voltage curve and a current curve respectively generated when an electrochemical energy recovery device assembled by the carbon nanotube fiber (mass ratio of 1:4.2) prepared by the method for preparing the carbon nanotube fiber in fig. 1 is subjected to torsion.

FIG. 6 is a graph showing electrochemical double layer capacitance curves of carbon nanotube fibers (mass ratio 1:7.2) in a twisted state and an untwisted state, which are manufactured by the method of manufacturing carbon nanotube fibers of FIG. 1;

fig. 7A, 7B and 7C are a torsion density change curve, a voltage curve and a current curve generated when an electrochemical energy recovery device assembled by the carbon nanotube fiber (mass ratio of 1:7.2) prepared by the method of preparing the carbon nanotube fiber in fig. 1 is subjected to a torsion action, respectively.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

Referring to fig. 1 and 2, the carbon nanotube fiber provided by the present invention has a shell-core structure. The carbon nanotube fiber is suitable for use in an energy recovery device. The bulk density of the carbon nanotube fiber is 180-350 mg/cm³The diameter of the fiber is 0.4-1.2 mm, the mass ratio of the inner core material to the shell material is 1: 1.8-1: 7.2, the capacitance of an electrochemical double electric layer in a sodium chloride aqueous solution is 8.2-11.36F/g, the super-array carbon nano tubes of adjacent layers are different in orientation, and the tensile strength is 20-30 MPa. In addition, the carbon nanotube fiber can be used as a working electrode in a torsion energy recovery device.

The invention also provides a preparation method of the carbon nanotube fiber, which comprises the following steps (wherein the step one, the step two, the step three and the step four are not in sequence):

firstly, growing an array carbon nanotube material on a silicon wafer by using a physical vapor deposition method and a water-assisted chemical vapor deposition method.

Wherein, the physical vapor deposition process is for the catalyst, preferably, adopts the multi-target radio frequency reaction magnetron sputtering instrument to physically deposit the catalyst film system on the clean silicon chip substrate, comprising: firstly plating an alumina film on a substrate by reactive magnetron sputtering, then plating an iron film, and obtaining a catalyst film system with a proper thickness by controlling the film plating time, wherein the film plating time is less than 30s of alumina and 30s-60s of iron.

The water-assisted chemical vapor deposition process is directed to the growth of carbon nanotubes, preferably: and (3) putting the silicon wafer plated with the catalyst film into a tubular furnace, and introducing high-purity argon with higher flow to clean the gas environment in the furnace for 20 min. And then starting a temperature rise program, introducing hydrogen simultaneously, reducing the oxidized iron atoms, raising the temperature of the tube furnace from room temperature to a growth temperature (preferably 700-750 ℃), and annealing at the temperature for 5 min. During the annealing process, the iron film on the surface of the substrate is cracked into iron nanoparticles. And then entering a growth stage of the carbon nano tube, wherein the ethylene gas flow is 100-150sccm, the water flow is less than 100ppm, and the growth time is 30-40min (different growth times can influence the structural parameters of the array carbon nano tube, and the structure of the array carbon nano tube in the range is optimal). In a specific application scenario, the conditions such as the flow rate of the reaction gas, the growth time and the like can be controlled, wherein the growth temperature of the water-assisted chemical vapor deposition method is 750 ℃, and the temperature is C₂H₄The flow rate is 150sccm, and the growth time is 36 min; the prepared array carbon nanotube material mainly comprises 2-wall (average tube diameter is 5.4nm) and 3-wall (average tube diameter is 7.3nm) carbon nanotubes, the purity is as high as 99.5 percent, the length of the carbon nanotube is more than 700 mu m, and the density is 41.3mg/cm³And, the ratio of 2-wall to 3-wall carbon nanotubes is about 3:2 at this time. The 2-wall carbon nanotube and the 3-wall carbon nanotube are all few-wall carbon nanotubes, and have larger specific surface area and better capacitance performance.

And step two, stripping the array carbon nanotube material prepared in the step one from the silicon wafer, and preparing the array carbon nanotube film by a mechanical rolling process. Specifically, the volume density of the array carbon nanotube film is 183mg/cm corresponding to the scheme in the specific application scenario³The thickness is about 100 mu m, and the area density is 2.75mg/cm²。

And step three, growing the carbon nanotube material of the super-ordered array on the silicon wafer by using a physical vapor deposition method and a water-assisted chemical vapor deposition method.

The physical vapor deposition process is specific to the catalyst, and the difference from the first step is that the iron catalyst coating time is 90-150 s, the longer the iron coating time is, the more iron is obtained, the larger the particle diameter of the iron catalyst is during annealing, and the larger the diameter of the grown carbon tube is, so that the subsequent super-ordered carbon nanotube array can be obtained.

The water-assisted chemical vapor deposition process is directed to the growth of carbon nanotubes, preferably: and (3) putting the silicon wafer plated with the catalyst film into a tubular furnace, and introducing high-purity argon with higher flow to clean the gas environment in the furnace for 20 min. And then starting a temperature rise program, introducing hydrogen simultaneously, reducing the oxidized iron atoms, raising the temperature of the tube furnace from room temperature to a growth temperature (preferably 680-700 ℃), and annealing at the temperature for 5 min. During the annealing process, the iron film on the surface of the substrate is cracked into iron nanoparticles. Then entering the growth stage of the carbon nano tube, wherein the ethylene gas flow is 40-80sccm, the water flow is less than 100ppm, the growth time is 10-20min (different growth times can influence the structural parameters of the carbon nano tube array in the super-alignment way, the structure of the carbon nano tube array in the super-alignment way is optimal in the range), the length of the obtained carbon nano tube array in the super-alignment way is less than 300 mu m, and the density is 60-70mg/cm³。

In a specific application scenario, the conditions such as the flow rate of the reaction gas, the growth time and the like can be controlled, wherein the growth temperature of the water-assisted chemical vapor deposition method is 680 ℃, and C₂H₂The flow rate is 50sccm, and the growth time is 20 min; the prepared super-array carbon nanotube material mainly comprises 8-wall (average tube diameter is 9.98nm) and 9-wall (average tube diameter is 11.1nm) carbon nanotubes, the purity is up to 99.388%, the length of the carbon nanotubes is about 271 μm, and the density is 63.1mg/cm³And, in this case, the ratio of 8-wall to 9-wall carbon nanotubes is about 2: 1. The super-ordered array carbon nanotube material, namely the spinnable carbon nanotube material, can be drawn into wires and films and has good film forming property.

And step four, preparing the super-array carbon nanotube material prepared in the step three into a super-ordered carbon nanotube film array by a dry film drawing process. Utensil for cleaning buttockIn the concrete application scenario, the thickness of the carbon nanotube film array is about 0.02 μm, and the area density is about 2 μ g/cm²。

And step five, preparing the carbon nanotube fiber with the shell-core structure by using the stacking body of the array carbon nanotube film and the super-ordered carbon nanotube film array with a certain number of layers through a Fermat torsion process. Specifically, the mass ratio of an inner core material (an array carbon nanotube film) to a shell material (a super-ordered carbon nanotube film array) in the stacking body is 1: 1.8-1: 7.2; the bulk density of the carbon nanotube fiber is 180-350 mg/cm³The fiber diameter is 0.4-1.2 mm; when the stacking body of the array carbon nanotube film and the super-ordered carbon nanotube film array is subjected to Fermat torsion (namely, twisted according to the Fermat torsion mode), the super-ordered carbon nanotube film arrays with different layers are mutually hindered, and the super-ordered carbon nanotube film arrays of adjacent layers are relatively rotated under the action of Fermat torsion, so that the orientations of the shell layer super-ordered carbon nanotube film arrays are different, the carbon nanotubes in the carbon nanotube film arrays are converted into node contact form from main linear contact form, the mutual embedding of the shell layer super-ordered carbon nanotube film arrays is reduced, and the structure recoverability in the carbon nanotube fiber testing process is improved.

The carbon nanotube fiber can be used as a working electrode for assembling a torsion energy recovery device. The carbon nanotube fiber can reduce the available electrochemical surface area, reduce the capacitance, increase the electrochemical potential and generate an electric signal corresponding to the torsion change after being twisted

The following specific examples further illustrate the present invention in detail.

Example 1

The method for preparing carbon nanotube fibers provided by the first embodiment of the present invention mainly includes the following steps:

(1) a silicon wafer (diameter: 10cm) was sonicated in ethanol for 20min to remove dust on the surface, followed by blowing nitrogen gas to a dry state. After the silicon chip is plated with the catalyst film, the silicon chip is placed in a tube furnace (750 ℃) to grow an array carbon nanotube material to prepare the array carbon nanotube materialThe nanotube material mainly comprises 2-wall (average tube diameter of 5.4nm) and 3-wall (average tube diameter of 7.3nm) carbon nanotubes, the purity is up to 99.5%, the length of the carbon nanotube is more than 700 μm, and the density is 41.3mg/cm³。

(2) The array carbon nanotube material is peeled off from the silicon wafer and is prepared into an array carbon nanotube film through a mechanical rolling process. Wherein the volume density of the array carbon nanotube film is 183mg/cm³The thickness is about 100 mu m, and the area density is 2.75mg/cm²。

(3) A silicon wafer (diameter: 10cm) was sonicated in ethanol for 20min to remove dust on the surface, followed by blowing nitrogen gas to a dry state. After the silicon wafer is plated with the catalyst film, the silicon wafer is placed in a tube furnace (680 ℃) to grow a super-array carbon nanotube material, the prepared super-array carbon nanotube material mainly comprises 8-wall (the average tube diameter is 9.98nm) and 9-wall (the average tube diameter is 11.1nm) carbon nanotubes, the purity is up to 99.388%, the length of the carbon nanotubes is about 271 mu m, and the density is 63.1mg/cm³。

(4) And preparing the prepared super-array carbon nanotube material into a super-ordered carbon nanotube film array by a dry film drawing process. Wherein the thickness of the super-parallel carbon nanotube film array is about 0.02 μm, and the area density is about 2 μ g/cm²。

(5) And stacking the array carbon nanotube film and the super-ordered carbon nanotube film array, and preparing the carbon nanotube fiber with the shell-core structure by a Fermat torsion process. Wherein the mass ratio of the inner core material (array carbon nanotube film) to the shell material (super-ordered carbon nanotube film array) in the stack body is 1: 1.8; the bulk density of the carbon nanotube fiber is 350mg/cm³The fiber diameter was 0.4 mm.

In order to detect the electrochemical double-layer capacitance performance of the prepared carbon nanotube fiber, a sodium chloride aqueous electrolyte is configured as follows to test and obtain the electrochemical double-layer capacitance of the carbon nanotube fiber under different torsional densities, specifically:

(1) preparing an aqueous electrolyte: 35.06g of sodium chloride and 1L of deionized water are mixed uniformly to prepare a 0.6M/L sodium chloride aqueous solution.

(2) And assembling a torsion energy recovery device by taking carbon nanotube fibers as a working electrode, and immersing the torsion energy recovery device and a reference electrode in a 0.6M NaCl aqueous solution to form an electrochemical three-electrode system testing unit.

(3) The torsion energy recovery device was tested for capacitance curves at different torsion densities (0rad/cm and 19.6 rad/cm). The voltage sweep rate was 20mV/s and the potential varied from 0.3V to 0.6V. It can be seen from fig. 2 that the capacitance decreases with a twist density of 19.6rad/cm, which is reflected in the capacitance curve, i.e. the area of the capacitance curve decreases, due to the twist resulting in a decrease in the electrochemically available surface area of the carbon nanotube fiber.

Referring to fig. 3A, 3B and 3C, the torsional energy recovery device using the carbon nanotube fiber as the working electrode has a phase difference (-135 °) between the short-circuit current and the pressure change in the linear torsional motion mode.

Example 2

(1) a silicon wafer (diameter: 10cm) was sonicated in ethanol for 20min to remove dust on the surface, followed by blowing nitrogen gas to a dry state. After the silicon chip is plated with the catalyst film, the silicon chip is placed in a tube furnace (750 ℃) to grow an array carbon nanotube material, the prepared array carbon nanotube material mainly comprises 2-wall (the average tube diameter is 5.4nm) and 3-wall (the average tube diameter is 7.3nm) carbon nanotubes, the purity is up to 99.5 percent, the length of the carbon nanotube is more than 700 mu m, and the density is 41.3mg/cm³。

(3) A silicon wafer (diameter: 10cm) was sonicated in ethanol for 20min to remove dust on the surface, followed by blowing nitrogen gas to a dry state. After the silicon wafer is plated with the catalyst film, the silicon wafer is placed in a tube furnace (680 ℃) to grow the super-array carbon nano tubeThe prepared super-array carbon nanotube material mainly comprises 8-wall (the average tube diameter is 9.98nm) and 9-wall (the average tube diameter is 11.1nm) carbon nanotubes, the purity is up to 99.388 percent, the length of the carbon nanotube is about 271 mu m, and the density is 63.1mg/cm³。

(5) And stacking the array carbon nanotube film and the super-ordered carbon nanotube film array, and preparing the carbon nanotube fiber with the shell-core structure by a Fermat torsion process. Wherein the mass ratio of the inner core material (array carbon nanotube film) to the shell material (super-ordered carbon nanotube film array) in the stack body is 1: 4.2; the bulk density of the carbon nanotube fiber is 220mg/cm³The fiber diameter was 0.76 mm.

(3) The torsion energy recovery device was tested for capacitance curves at different torsion densities (0rad/cm and 27.5 rad/cm). The voltage sweep rate was 20mV/s and the potential varied from 0.3V to 0.6V. It can be seen from fig. 4 that the capacitance decreases with a twist density of 27.5rad/cm, which is reflected in the capacitance curve, i.e., the area of the capacitance curve decreases, due to the twist resulting in a decrease in the electrochemically available surface area of the carbon nanotube fiber.

Referring to fig. 5A, 5B and 5C, the torsional energy recovery device using the carbon nanotube fiber as the working electrode has a phase difference (-135 °) between the short-circuit current and the pressure change in the linear torsional motion mode.

Example 3

(3) A silicon wafer (diameter: 10cm) was sonicated in ethanol for 20min to remove dust on the surface, followed by blowing nitrogen gas to a dry state. After the silicon wafer is plated with the catalyst film, the silicon wafer is placed in a tube furnace (680 ℃) to grow a super-array carbon nanotube material, the prepared super-array carbon nanotube material mainly comprises 8-wall (the average tube diameter is 9.98nm) and 9-wall (the average tube diameter is 11.1nm) carbon nanotubes, the purity is up to 99.388 percent, the length of the carbon nanotubes is about 271 mu m, and the density is 63.1mg/cm³。

(5) And stacking the array carbon nanotube film and the super-ordered carbon nanotube film array, and preparing the carbon nanotube fiber with the shell-core structure by a Fermat torsion process. Wherein, the inner core material (array carbon nano tube) in the stacking bodyThe mass ratio of the film) to the shell material (the super-ordered carbon nanotube film array) is 1: 7.2; the bulk density of the carbon nanotube fiber is 180mg/cm³The fiber diameter was 1.2 mm.

(3) The torsion energy recovery device was tested for capacitance curves at different torsion densities (0rad/cm and 27.5 rad/cm). The voltage sweep rate was 20mV/s and the potential varied from 0.3V to 0.6V. As can be seen from FIG. 6, the capacitance decreases with a twist density of 27.5rad/cm, reflected on the capacitance curve, i.e., the area of the capacitance curve decreases due to the twist resulting in a decrease in the electrochemically available surface area of the carbon nanotube fiber.

Referring to fig. 7A, 7B and 7C, the torsional energy recovery device using the carbon nanotube fiber as the working electrode has a phase difference (-135 °) between the short-circuit current and the pressure change in the linear torsional motion mode.

In the above embodiment, since the densities of the inner core material and the shell material are different, the number of layers of the shell carbon nanotube film can be adjusted (i.e., the mass ratio of the core layer to the shell layer is adjusted), and the change in the number of layers of the shell carbon nanotube causes the change in the mass ratio of the core layer to the shell layer, so that the density and the diameter of the final product are also changed.

According to the carbon nanotube fiber and the preparation method thereof, after the carbon nanotube fiber is twisted, the available electrochemical surface area of the carbon nanotube fiber can be reduced, the capacitance can be reduced, the electrochemical potential can be improved, and an electric signal corresponding to pressure change can be generated. In addition, the carbon nanotube fiber has a shell-core structure, the electrochemical double-layer capacitance of the carbon nanotube fiber is about 8.2-11.36F/g in 0.6M NaCl solution, and the electrochemical available surface area can be reduced to the maximum extent during twisting, so that large capacitance change is caused, and the electrochemical potential of the carbon nanotube fiber is improved.

It will be understood by those skilled in the art that the foregoing is only a preferred embodiment of the present invention, and is not intended to limit the invention, and that any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the present invention.

Claims

Translated fromChinese

1.一种碳纳米管纤维的制备方法，其特征在于，对阵列碳纳米管材料进行辊压成膜得到阵列碳纳米管薄膜，对超顺排碳纳米管材料进行干法拉膜得到超顺排碳纳米管阵列薄膜；然后，以阵列碳纳米管薄膜作为内芯材料，超顺排碳纳米管阵列薄膜作为壳层材料，将两种薄膜材料堆垛后进行费马扭转得到具有壳芯结构的碳纳米管纤维；碳纳米管纤维的体积密度为180～350mg/cm³，纤维直径为0.4～1.2mm，内芯材料与壳层材料的质量比为1:1.8～1:7.2。1. a preparation method of carbon nanotube fiber, it is characterized in that, array carbon nanotube material is carried out rolling film forming to obtain array carbon nanotube thin film, and super-aligned carbon nanotube material is carried out by dry method to obtain super-aligned carbon nanotube material. Carbon nanotube array film; then, using the array carbon nanotube film as the inner core material and the super-aligned carbon nanotube array film as the shell material, stacking the two film materials and performing Fermat twisting to obtain a shell-core structure. Carbon nanotube fibers; the bulk density of the carbon nanotube fibers is 180-350 mg/cm³ , the fiber diameter is 0.4-1.2 mm, and the mass ratio of the inner core material to the shell material is 1:1.8-1:7.2.

2.如权利要求1所述的碳纳米管纤维的制备方法，其特征在于，所述阵列碳纳米管材料是按照如下方法获得：先利用物理气相沉积法在硅衬底上沉积催化剂薄膜，再利用水助化学气相沉积法在硅衬底的催化剂薄膜上生长阵列碳纳米管材料，并将阵列碳纳米管材料自所述硅衬底上剥离以备使用。2. The method for preparing carbon nanotube fibers as claimed in claim 1, wherein the arrayed carbon nanotube material is obtained by the following method: first, a catalyst film is deposited on a silicon substrate by a physical vapor deposition method, and then The arrayed carbon nanotube material is grown on the catalyst film of the silicon substrate by water-assisted chemical vapor deposition, and the arrayed carbon nanotube material is peeled off from the silicon substrate for use.

3.如权利要求2所述的碳纳米管纤维的制备方法，其特征在于：水助化学气相沉积过程中，所述阵列碳纳米管材料的生长温度为750℃，碳源气体C₂H₄的流量为150sccm，生长时间为36min。3 . The method for preparing carbon nanotube fibers according to claim 2 , wherein in the process of water-assisted chemical vapor deposition, the growth temperature of the arrayed carbon nanotube material is 750° C., and the carbon source gas is C₂ H_{4 .} The flow rate was 150sccm, and the growth time was 36min.

4.如权利要求1所述的碳纳米管纤维的制备方法，其特征在于，所述超顺排碳纳米管材料是按照如下方法获得：先利用物理气相沉积法在硅衬底上沉积催化剂薄膜，再利用水助化学气相沉积法在硅衬底的催化剂薄膜上生长超顺排碳纳米管阵列，并将超顺排碳纳米管阵列自所述硅衬底上剥离得到超顺排碳纳米管材料以备使用。4. the preparation method of carbon nanotube fiber as claimed in claim 1, is characterized in that, described super-aligned carbon nanotube material is obtained according to the following method: first utilize physical vapor deposition method to deposit catalyst film on silicon substrate , and then use the water-assisted chemical vapor deposition method to grow the super-aligned carbon nanotube array on the catalyst film of the silicon substrate, and peel the super-aligned carbon nanotube array from the silicon substrate to obtain the super-aligned carbon nanotube. material ready for use.

5.如权利要求4所述的碳纳米管纤维的制备方法，其特征在于：水助化学气相沉积过程中，所述超顺排碳纳米管材料的生长温度为680℃，碳源气体C₂H₂流量为50sccm，生长时间为20min。5 . The method for preparing carbon nanotube fibers according to claim 4 , wherein in the water-assisted chemical vapor deposition process, the growth temperature of the super-aligned carbon nanotube material is 680° C., and the carbon source gas is C₂ ._The H flow was 50 sccm and the growth time was 20 min.

6.如权利要求1所述的碳纳米管纤维的制备方法，其特征在于：所述阵列碳纳米管材料包括2壁和3壁碳纳米管，其碳纳米管长度大于700μm，密度为41.3mg/cm³；所述超顺排碳纳米管材料包括8壁和9壁碳纳米管，其碳纳米管长度约271μm，密度为63.1mg/cm³。6 . The method for preparing carbon nanotube fibers according to claim 1 , wherein the arrayed carbon nanotube material comprises 2-walled and 3-walled carbon nanotubes, and the carbon nanotubes have a length greater than 700 μm and a density of 41.3 mg. 7 . /cm³ ; the super-aligned carbon nanotube material includes 8-walled and 9-walled carbon nanotubes, and the carbon nanotubes have a length of about 271 μm and a density of 63.1 mg/cm³ .

7.按照权利要求1-6任意一项所述的制备方法获得的一种碳纳米管纤维。7. A carbon nanotube fiber obtained by the preparation method according to any one of claims 1-6.

8.如权利要求7所述的碳纳米管纤维，其特征在于：所述碳纳米管纤维的体积密度为180～350mg/cm³，纤维直径为0.4～1.2mm，内芯材料与壳层材料的质量比为1:1.8～1:7.2，在氯化钠水性溶液中的电化学双电层电容为8.2～11.36F/g。8 . The carbon nanotube fiber according to claim 7 , wherein the carbon nanotube fiber has a bulk density of 180-350 mg/cm³ , a fiber diameter of 0.4-1.2 mm, and an inner core material and a shell layer material. 9 . The mass ratio is 1:1.8～1:7.2, and the electrochemical double layer capacitance in the aqueous sodium chloride solution is 8.2～11.36F/g.

9.如权利要求7所述的碳纳米管纤维，其特征在于：所述碳纳米管纤维中相邻层的超顺排碳纳米管取向不同。9 . The carbon nanotube fiber according to claim 7 , wherein the super-aligned carbon nanotubes of adjacent layers in the carbon nanotube fiber are oriented differently. 10 .