JP6719243B2 - Method for producing carbon nanotube wire - Google Patents

Description

The present invention relates to a method for manufacturing a carbon nanotube wire, and more particularly to a method for manufacturing a carbon nanotube wire composed of carbon nanotubes doped with a different element.

2. Description of the Related Art Conventionally, as electric power lines and signal lines in various fields such as automobiles and industrial equipment, electric wires composed of a core wire made of one or a plurality of wire materials and an insulating coating covering the core wire have been used. Copper or a copper alloy is usually used as the material of the wire material constituting the core wire from the viewpoint of electrical characteristics, but in recent years, aluminum or an aluminum alloy has been proposed from the viewpoint of weight reduction. For example, the specific gravity of aluminum is about 1/3 of the specific gravity of copper, and the conductivity of aluminum is about 2/3 of the conductivity of copper (when pure copper is 100% IACS, pure aluminum is about 66% IACS). In order to pass the same current as the copper wire into the aluminum wire, it is necessary to increase the cross-sectional area of the aluminum wire to about 1.5 times the cross-sectional area of the copper wire. Even if a large aluminum wire is used, the mass of the aluminum wire is about half the mass of the pure copper wire, and thus the use of the aluminum wire is advantageous from the viewpoint of weight reduction.

Against the background described above, in recent years, high performance and high functionality of automobiles, industrial equipment, etc. have been promoted, and along with this, the number of arrangements of various electric equipment, control equipment, etc. has increased. The number of wirings of electric wirings used in these devices also tends to increase. On the other hand, in order to improve the fuel efficiency of moving bodies such as automobiles for environmental friendliness, it is strongly desired to reduce the weight of the wire rod.

As one of the new means for achieving such further weight reduction, a technology of utilizing carbon nanotubes as a wire rod has been newly proposed. The carbon nanotube is a three-dimensional mesh structure composed of a single layer of a tubular body having a mesh structure of hexagonal lattice or a multi-layer arranged substantially coaxially, and is lightweight, and has conductivity, current capacity, Due to its excellent properties such as elasticity and mechanical strength, it has been attracting attention as a material that can replace the metals used for power lines and signal lines.

The specific gravity of carbon nanotubes is about ⅕ of the specific gravity of copper (about ½ of aluminum), and carbon nanotubes alone are higher than copper (resistivity 1.68×10 ⁻⁶ Ω·cm). Shows conductivity. Therefore, theoretically, if a plurality of carbon nanotubes are twisted together to form a carbon nanotube aggregate, further weight reduction and high conductivity can be realized. However, when carbon nanotubes in the unit of nm are twisted together to produce a carbon nanotube aggregate in the unit of μm to mm, the contact resistance between the carbon nanotubes and the formation of internal defects cause the resistance value of the entire wire rod to increase. Therefore, it is difficult to use the carbon nanotubes as they are as a wire rod.

Therefore, as one of methods for improving the conductivity of the aggregate of carbon nanotubes, a method of performing a doping treatment on the carbon nanotubes, which is a structural unit, has been proposed. For example, carbon nanotubes are heated together with boron oxide (B ₂ O ₃ ) in an argon stream at 1000° C. for 4 hours, and the boron oxides (B ₂ O ₃ , B ₂ O ₂ ) that have reached the carbon nanotubes by vaporization or surface diffusion. And the like) cause a chemical reaction to partially dissolve boron in the carbon nanotube, thereby producing a carbon nanotube containing boron (Patent Document 1).

JP-A-2000-281323

However, in the above patent document, carbon nanotube simple substance and boron oxide are placed in a graphite crucible in a stacked manner, and since the carbon nanotube simple substance and boron oxide are heated in the graphite crucible, the doping position of the carbon nanotube cannot be controlled, There is a problem that the dope position or the amount of dope is apt to be biased, and when a plurality of generated carbon nanotubes are bundled to form a carbon nanotube bundle, the conductivity of the carbon nanotube bundle, and eventually the carbon nanotube wire, varies. Further, in the above manufacturing method, since the carbon nanotubes are heated in an inert gas, the defective carbon nanotubes cannot react with oxygen and remain, so that the carbon nanotube wire having good conductivity cannot be manufactured. In addition, the production method in which the carbon nanotubes are taken out from the graphite crucible after being doped with the carbon nanotubes alone and the carbon nanotubes are twisted together to form the carbon nanotube wire rod is low in productivity of the wire rod and cannot be said to be excellent in mass production.

An object of the present invention is to provide a method for producing a carbon nanotube wire which has good conductivity, suppresses variations, and has high productivity and mass production.

In order to achieve the above object, a method for producing a carbon nanotube wire according to the present invention is a method for producing a carbon nanotube wire formed by twisting a plurality of carbon nanotubes, and a plurality of carbons having a layer structure of one or more layers. A carbon nanotube forming step of twisting the nanotubes to form a carbon nanotube wire, a purification step of purifying the carbon nanotube wire, and a doping step of doping the carbon nanotube wire after purification with a different element To do.

In the refining step, the carbon nanotube wire is oxidized to remove impurities such as defective carbon nanotubes and amorphous carbon from the carbon nanotube wire.

In the purification step, it is preferable to heat the carbon nanotube wire at 300°C to 700°C.

It is preferable that the doping step includes an immersion step of immersing the carbon nanotube wire in a liquid containing the different element, and a heating step of heating the carbon nanotube wire after the immersion step.

In the dipping step, the carbon nanotube wire is preferably dipped in a liquid containing at least one different element selected from the group consisting of nitrogen, boron and silicon.

The liquid preferably contains any one of an aqueous solution, an organic solvent, an ionic liquid, and a supercritical fluid.

In the heating step, the carbon nanotube wire is preferably fired at 1300°C to 1800°C.

Further, in the heating step, it is preferable that at least one of the carbon atoms located at the apexes of the hexagonal lattice, which is a constituent unit of the carbon nanotube, is replaced with the different element.

The carbon nanotubes preferably have a two-layer or three-layer structure.

According to the present invention, a carbon nanotube wire formed by twisting a plurality of carbon nanotubes having a layered structure of one or more layers is refined, and then the carbon nanotube wire is doped with a different element. That is, the defective carbon nanotubes are removed from the carbon nanotube wire by the purification treatment performed before the doping treatment. When the carbon nanotube has a defect, a different element is preferentially bonded to the defect during the doping process, and thus it is difficult to substitute with the carbon atom of the hexagonal lattice constituting the carbon nanotube. Since the carbon nanotubes having carbon are removed before the doping process, the subsequent doping process ensures that the carbon atoms of the hexagonal lattice forming the carbon nanotubes are not dissociated by the preferential elements. It becomes possible to replace. Therefore, it is possible to manufacture a carbon nanotube wire material that has good conductivity and suppresses variations in conductivity.

Further, since the formation, purification and doping of the carbon nanotube wire can be performed in a series of flows, for example, by combining with a production method capable of producing the carbon nanotube wire from the carbon raw material, carbon containing a different element from the carbon raw material can be used. The nanotube wire can be continuously manufactured, the productivity of the wire can be increased, and a manufacturing method excellent in mass production can be provided.

Furthermore, in the doping process, the carbon nanotube wire from which defective carbon nanotubes have been removed is immersed in a liquid containing a different element, and the carbon nanotube wire after the immersion treatment is heated, so that the liquid is evenly distributed in the carbon nanotube wire. By penetrating into, it is possible to realize more uniform conductivity.

It is an expansion perspective view which shows roughly the structure of the carbon nanotube bundle in the carbon nanotube manufactured with the manufacturing method of the carbon nanotube wire which concerns on embodiment of this invention. It is a figure which shows an example of arrangement|positioning of the different element doped in the carbon nanotube in FIG. 1, (a) is a top view, (b) is a front view. It is a figure which shows an example of arrangement|positioning of the different element doped in the carbon nanotube which has a single-layer structure, (a) is a top view and (b) is a front view. It is a flow chart which shows the manufacturing method of the carbon nanotube wire rod concerning this embodiment. 5 is a flowchart showing details of a doping step in the manufacturing method of FIG. 4. It is a figure which shows an example of the manufacturing apparatus which manufactures a carbon nanotube by the floating catalyst vapor phase growth method.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

<Structure of carbon nanotube wire>
Carbon nanotube wire rods (hereinafter referred to as CNT wire rods) manufactured by the manufacturing method according to the present embodiment include a plurality of carbon nanotube bundles 11A, 11A,... Alternatively, it is referred to as a CNT composite), and a plurality of these CNT bundles 11A are twisted together. The outer diameter of the CNT wire rod 1 is 0.01 to 1 mm.

As shown in the enlarged perspective view of FIG. 1, the CNT bundle 11A is a bundled body in which a plurality of carbon nanotubes 11a, 11a,... The axial directions are almost the same. Further, a plurality of voids 11B are formed between the outermost layers of the plurality of CNTs 11a, 11a,... Along the longitudinal direction of the CNT bundle 11A.

The CNTs 11a that compose the CNT bundle 11A are tubular bodies having a single-layer structure or a multi-layer structure, and are called SWNTs (single-walled nanotubes) and MWNTs (multi-walled nanotubes), respectively. Although only CNTs having a two-layer structure are shown in FIG. 1 for convenience, there are actually CNTs having a three-layer structure. CNTs having a single-layer structure or a layer structure of four or more layers may be included in the bundle 11 of CNTs, but the amount thereof is smaller than that of CNTs having a two-layer structure or a three-layer structure.

When the CNT 11a has a two-layer structure, it is a three-dimensional mesh structure in which two cylindrical bodies T1 and T2 having a mesh structure of a hexagonal lattice are arranged substantially coaxially, and a DWNT (Double-walled nanotube) Called. The hexagonal lattice, which is a structural unit, is a six-membered ring in which carbon atoms are arranged at the vertices, and adjacent to other six-membered rings, these are continuously bonded. Further, the plurality of CNTs 11a, 11a,... Are directly doped with a predetermined different element by a doping process described later.

The properties of the CNT 11a depend on the chirality of the tubular body as described above. Chirality is roughly divided into armchair type, zigzag type, and other chiral types. The armchair type exhibits metallic behavior, the chiral type exhibits semiconductivity, and the zigzag type exhibits intermediate behavior. Therefore, the conductivity of CNTs varies greatly depending on which chirality they have, and in order to improve the conductivity of CNT aggregates, it has been important to increase the proportion of armchair-type CNTs that exhibit metallic behavior. It was On the other hand, it has been known that by doping a chiral CNT having a semiconducting property with a substance having an electron-donating or electron-accepting property (a different element), a metallic behavior is exhibited. Further, in a general metal, when a different element is doped, conduction electrons are scattered inside the metal to reduce the conductivity. Similarly, when a metallic CNT is doped with a different element, , Causes a decrease in conductivity.

Thus, since it can be said that the doping effect on the metallic CNT and the semiconducting CNT has a trade-off relationship from the viewpoint of conductivity, theoretically, the metallic CNT and the semiconducting CNT are produced separately. However, it is desirable to combine these after performing the doping process only on the semiconductor CNT. However, it is difficult to selectively produce metallic CNTs and semiconducting CNTs by the current production technique, and metallic CNTs and semiconducting CNTs are produced in a mixed state. Therefore, in order to improve the conductivity of the CNT wire made of a mixture of metallic CNTs and semiconducting CNTs, it is preferable to select a CNT structure in which doping treatment with a different element/molecule is effective.

In a CNT bundle 11A configured by bundling a plurality of CNTs 11a, 11a,..., the ratio of the sum of the number of CNTs having a two-layer structure or a three-layer structure to the number of CNTs 11a, 11a,. It is preferably at least 50%, more preferably at least 75%. That is, the total CNT total number of N _TOTAL of which constitutes one of the CNT aggregate, the total CNT the sum of the number of CNT (2) having a two-layer structure of the N _{CNT (2),} 3-layer among the entire CNT When the sum of the numbers of CNTs (3) having a structure is N _{CNT (3)} , it can be represented by the following formula (1).
(N _CNT(2) + N _CNT(3) )/N _TOTAL ×100 (%) ≧50 (%) (1)

A CNT having a small number of layers such as a two-layer structure or a three-layer structure has relatively higher conductivity than a CNT having a larger number of layers. In addition, the dopant is introduced inside the innermost layer of CNTs or in the gaps between CNTs formed by a plurality of CNTs. The interlayer distance of CNT is equivalent to 0.335 nm which is the interlayer distance of graphite, and in the case of multi-layer CNT, it is difficult in size to enter the dopant between the layers. From this fact, the doping effect is exhibited by introducing the dopant inside and outside the CNT, but in the case of the multi-layer CNT, the doping effect of the tube located inside not in contact with the outermost layer and the innermost layer becomes difficult to be exhibited. .. For the reasons described above, when each CNT having a multi-layer structure is subjected to a doping treatment, the CNT having a two-layer structure or a three-layer structure has the highest doping effect. In addition, the dopant is often a highly reactive reagent that exhibits strong electrophilicity or nucleophilicity. Single-layer CNTs have lower rigidity than multi-layers and are inferior in chemical resistance. Therefore, the doping process may destroy the structure of CNTs themselves. Therefore, the present invention focuses on the number of CNTs having a two-layer structure or a three-layer structure contained in the CNT aggregate. Further, if the sum ratio of the number of CNTs having a two-layer or three-layer structure is less than 50%, the ratio of CNTs having a single-layer structure or a multi-layer structure having four or more layers becomes high, and the CNT aggregate as a whole is doped. The effect becomes small and it becomes difficult to obtain high conductivity. Therefore, the ratio of the sum of the numbers of CNTs having a two-layer or three-layer structure is set to a value within the above range.

Further, the outer diameter of the outermost layer of CNTs forming the CNT bundle 11 is preferably 5.0 nm or less. If the outer diameter of the outermost layer of the CNTs constituting the CNT aggregate 11 exceeds 5.0 nm, the porosity due to the gap between the CNTs and the innermost layer increases, and the conductivity decreases, which is not preferable. ..

In this embodiment, it is preferable that the CNTs forming the CNT bundle 11A have no defect in the layer structure. The defect referred to here is, for example, a lattice defect such as a five-membered ring or a seven-membered ring formed in a regular lattice array consisting of a six-membered ring, or a portion where the covalent bond between carbon atoms in the regular array is broken. Say When the CNT 11a has a defect, when the CNT wire is doped with a different element, the different element is preferentially bonded to the defect, and thus it is difficult to substitute the carbon atom of the hexagonal lattice forming the carbon nanotube. Therefore, in this embodiment, it is preferable that the CNTs forming the CNT bundle 11A have no defects. Although defects may be present in the CNT, it is desirable that the defects are a very small number that do not affect the substitution reaction with carbon atoms of the hexagonal lattice in the doping process.

(Arrangement of different elements in CNT)
2A and 2B are diagrams showing the arrangement of different elements doped in the CNT 11a in FIG. 1, where FIG. 2A is a top view and FIG. 2B is a front view.
As shown in FIGS. 2A and 2B, the CNT 11a includes a CNT body 11a-1 having a multi-layered structure including tubular bodies T1 and T2, and an outermost layer forming the tubular body T2. The different element 11a-2 located at the apex of the hexagonal lattice as a unit is provided. This heterogeneous element 11a-2 is incorporated in the carbon skeleton of CNT and is substituted with any of the six carbon atoms 13a located at the apex of the hexagonal lattice by carbon substitution type doping treatment. .. As described above, by disposing the different element 11a-2 in the carbon skeleton of the CNT 11a, many carriers can be generated in the CNT itself.

In FIG. 2, the heterogeneous element 11a-2 is substituted with any of the six carbon atoms 13a located at the apexes of the hexagonal lattice, but the present invention is not limited to this. It may be substituted with a plurality of one carbon atom 13a. Further, the heterogeneous element 11a-2 is incorporated in the outermost layer (cylindrical body T2) of the CNT 11a having a two-layer structure, but it is not limited to this and may be incorporated in the inner layer (cylindrical body T1). Further, the different element may be incorporated in the outermost layer of the CNT having a multi-layered structure having a three-layer structure, or may be incorporated in at least one inner layer of the multi-layered structure.

The different element 11a-2 is preferably at least one different element selected from the group consisting of nitrogen, boron and silicon. When an atom in the vicinity of carbon in the periodic table is used as a different element, the electron arrangement is close to that of carbon, so that the substitution reaction with the carbon atom can be easily performed during the doping process.
The content of the different element 11a-2 in the CNT bundle 11a is preferably 0.1 atomic% to 50 atomic% in atomic composition percentage, and more preferably 10 atomic% or less.

In FIG. 2, the CNT 11a having a two-layer structure is doped with the different element 11a-2, but as shown in FIGS. 3A and 3B, the CNT having a single-layer structure is doped with the different element. May be. Specifically, the CNT 21a includes a CNT body 21a-1 having a single-layer structure, and a heterogeneous element 21a-2 constituting a part of the apex of a hexagonal lattice which is a constituent unit of the CNT body 21a-1. May be. As described above, since the heterogeneous element 21a-2 is located in the carbon skeleton of the CNT 21a having a single-layer structure, many carriers can be generated in the CNT itself as in the above-described multi-layer structure.

<Method for producing carbon nanotube wire>
FIG. 4 is a flowchart showing a method of manufacturing the carbon nanotube wire according to the present embodiment, and FIG. 5 is a flowchart showing details of the doping process in the manufacturing method of FIG.
As shown in FIG. 4, first, by a floating catalytic vapor deposition (CCVD) method, a mixture containing a catalyst and a reaction accelerator is supplied to a carbon source to produce a CNT wire rod in which a plurality of CNTs are twisted (step). S11). At this time, a saturated hydrocarbon having a six-membered ring can be used as the carbon source, a metal catalyst such as iron can be used as the catalyst, and a sulfur compound can be used as the reaction accelerator. For example, using a CNT manufacturing apparatus as shown in FIG. 6, inside the alumina tube 32 heated to about 1300° C. by the electric furnace 31, decahydronaphthalene as a carbon source, ferrocene as a catalyst, and a reaction accelerator. A raw material solution L containing thiophene is supplied by spraying. Further, hydrogen is supplied as the carrier gas G into the alumina tube 32. The obtained CNTs are collected in a sheet form by the collection machine 33, and the CNT wire rod is produced by winding and twisting the sheet.

At this time, a saturated hydrocarbon having a six-membered ring can be used as the carbon source, a metal catalyst such as iron can be used as the catalyst, and a sulfur compound can be used as the reaction accelerator. In addition, in the present embodiment, considering that the proportion of SWNTs decreases as the carrier gas flow rate increases, the raw material composition and spraying conditions are adjusted to increase the proportion of CNTs having a two-layer or three-layer structure. Further, in order to adjust the size of iron as a catalyst so that the outer diameter of the outermost layer of CNT is 5.0 nm or less, the raw material is supplied to the reaction furnace by spraying so that the mist particle size becomes about 20 μm.

Then, a plurality of carbon nanotubes having one or more layer structure obtained in step S11 are twisted together to form a carbon nanotube wire (step S12).

Then, the CNT wire obtained in step S12 is refined (step S13). First, the CNT wire is subjected to an acid treatment to remove the residual iron catalyst. The CNT wire obtained by CCVD contains a large amount of catalyst, amorphous carbon, and the like, and the original characteristics of the CNT wire can be obtained by a purification process for removing these. In this embodiment, the CNT wire obtained in the above step is heated at a predetermined temperature in the atmosphere, and the heated CNT wire is highly purified with a strong acid.

Then, the highly purified CNT wire is subjected to a heat oxidation treatment to remove defective CNTs from the CNT wire. In the heat oxidation treatment, for example, the CNT wire is heated at 300 to 700° C. in the atmosphere to cause an oxidation reaction of carbon of the CNT having a defect, thereby removing impurities such as CNT having a defect and amorphous carbon from the CNT wire. .. This makes it possible to obtain a CNT wire that is composed of only CNTs that have no defects or a CNT wire that has very few defective CNTs.

Then, the purified CNT wire is doped with a different element (step S14). Specifically, the purified CNT wire is immersed in a liquid containing a different element for a predetermined time (FIG. 4, step S21). The liquid preferably contains any one of an aqueous solution, an organic solvent, an ionic liquid and a supercritical fluid. The content of the different element in the liquid is preferably 1 wt% to 50 wt %. The plurality of voids of the CNT bundle in the CNT wire are distributed substantially evenly in the cross section, and are evenly arranged along the longitudinal direction of the CNT bundle. Therefore, by immersing the CNT wire rod in the liquid as it is for a predetermined time, the liquid containing the different element uniformly penetrates into the CNT wire through the voids or the interface between the CNTs and the CNTs, and the different element is dispersed in the CNT wire. It can be distributed almost evenly.

Then, the CNT wire rod after the immersion treatment is heated to 1300° C. to 1800° C. in the atmosphere, preferably under an inert gas (step S22). By heating at a temperature within the above range, the foreign element enters the carbon skeleton and is replaced with any of the carbon atoms forming the hexagonal lattice. At this time, the different elements are uniformly dispersed and arranged in the CNT wire by the immersion treatment, and since the different elements are injected from the outer periphery of the CNT, the substitution reaction between the different elements and the carbon atoms is performed in the CNT wire. Be seen.
At this time, when the CNT is a multi-layer (MWNT), the layer located on the outer peripheral side is preferentially doped, and the inner layer is difficult to be doped. By setting the number ratio of CNTs having a two-layer or three-layer structure to 50% or more, the doping amount of the entire CNT aggregate can be increased and an excellent doping effect can be obtained.

As described above, according to the present embodiment, a CNT wire rod obtained by twisting a plurality of CNTs 11a having a layer structure of one or more layers is refined (step S13), and then the CNT wire rod is doped with a different element 11a-2. Yes (step S14). That is, since the CNT having a defect is removed from the CNT wire by the refining process performed before the doping process, the subsequent doping process does not cause the preferential bonding between the different element 11a-2 and the defect, and thus the CNT 11a is formed. It is possible to reliably replace the carbon atom of the rectangular lattice with a different element. Therefore, the CNT wire 1 having good conductivity can be manufactured.

In addition, since the formation, purification and doping of the CNT wire can be performed in a series of flows, for example, the heterogeneous element 11a-2 can be contained from the carbon raw material by using together the production method capable of producing the carbon nanotube wire from the carbon raw material. It becomes possible to continuously manufacture the CNT wire rod 1 which can be manufactured, the productivity of the wire rod can be enhanced, and a manufacturing method excellent in mass production can be provided.

Further, in the doping process, the CNT wire rod from which the defective CNTs are removed is immersed in a liquid containing the different element 11a-2 (step S21), and the CNT wire rod after the immersion process is heated (step S22). By uniformly permeating the liquid into the CNT wire, more uniform conductivity can be realized.

The CNT wire rod manufacturing method according to the embodiment of the present invention has been described above, but the present invention is not limited to the described embodiment, and various modifications and changes can be made based on the technical idea of the present invention. is there.

For example, a CNT-coated electric wire may be configured that includes a carbon nanotube wire rod formed by twisting the CNT bundles of the above embodiment and a coating layer that covers the outer periphery of the carbon nanotube wire rod. In particular, the CNT wire of the present embodiment is suitable as a material for a wire for electric wires for transmitting electric power and signals, and more suitable as a material for a wire for electric wires mounted on a moving body such as a four-wheeled vehicle. This is because it is lighter than a metal wire and is expected to improve fuel efficiency.

Moreover, you may comprise the wire harness which has at least one said carbon nanotube coating electric wire.

1 CNT wire rod 11A CNT bundle 11a CNT
11a-1 CNT body 11a-2 Foreign element 13a Carbon atom 21a CNT
21a-1 CNT main body 21a-2 Different element 31 Electric furnace 32 Alumina tube 33 Recovery machine T1 Cylindrical body T2 Cylindrical body

Claims (7)

A method of manufacturing a carbon nanotube wire rod, which comprises twisting a plurality of carbon nanotubes,
A carbon nanotube forming step of forming a carbon nanotube wire by twisting a plurality of carbon nanotubes having a layered structure of one or more layers,
A refining step for refining the carbon nanotube wire,
A doping step of doping the carbon nanotube wire after purification with a different element,
Have a,
The doping step includes
The carbon nanotube wire has an immersion step of immersing the carbon nanotube wire in a liquid containing the different element, and a heating step of heating the carbon nanotube wire after the immersion step,
The carbon nanotube has a two-layer or three-layer structure, and
In a carbon nanotube bundle formed by bundling a plurality of carbon nanotubes, the ratio of the sum of the number of carbon nanotubes having a two-layer structure or three-layer structure to the number of carbon nanotubes is 50% or more. A method of manufacturing a carbon nanotube wire rod. The method for producing a carbon nanotube wire according to claim 1, wherein in the purification step, the carbon nanotube wire is oxidized to remove defective carbon nanotubes from the carbon nanotube wire. The method for producing a carbon nanotube wire according to claim 2, wherein in the purifying step, the carbon nanotube wire is heated at 300°C to 700°C. Said immersion step, the carbon nanotube wire, nitrogen, characterized by immersion in a liquid containing at least one different element selected from the group consisting of boron and silicon, according to claim 1, wherein the carbon nanotube wire Production method. The liquid, aqueous, organic solvent, characterized in that it comprises any of the ionic liquids and supercritical fluids, according to claim 1 or 4 the method of manufacturing the carbon nanotube wire according. The heating step, characterized in that said firing the carbon nanotube wire at 1300 ° C. to 1800 ° C., The method according to claim 1 carbon nanotube wire according. The heating step, at least one of the carbon atoms located at the vertices of a hexagonal lattice is a structural unit of the carbon nanotube, characterized in that it replaced with the different element, according to claim 1, wherein the carbon nanotube wire Production method.

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