Method for producing an electrically conductive conductor bundle comprising at least one carbon conductor

Abstract

A method for producing an electrically conductive conductor bundle (1) comprising at least one carbon conductor (3), comprising the following steps: a) producing or providing the conductor bundle (1) as an intermediate product comprising at least one carbon conductor (3), the carbon conductor in particular comprising graphite, pyrolytic graphite, graphene, graphyne and / or carbon nanotubes, b) introducing the conductor bundle (1) and one or more intercalation substances (2), in particular one or more metal halides or one or more organic alkali metals, into the gaseous or liquid phase of a reactor volume (5), wherein the intercalation substances are suitable for intercalation into the material of the at least one carbon conductor (3) of the conductor bundle (1), and c) subjecting the conductor bundle (1) to a thermal treatment, wherein the reactor volume (5) is brought to a process temperature in order to induce intercalation (4), wherein atoms or molecules of the intercalation substance (2) are intercalated into the material of the respective carbon conductor (3), in particular accumulated on the carbon structure of the carbon conductor (3), in particular in the regions between the layers of the multilayer carbon structure.

Description

Existing technology

[0001] The invention relates to a method for producing a bundle of electrically conductive conductors comprising at least one carbon conductor.

[0002] Carbon conductors are known in the prior art. For example, electrical conductors made of graphite, pyrolytic graphite, carbon nanotubes or graphene are known in the prior art. In order to increase their electrical conductivity, it is known to dope carbon conductors. For example, DE102019220177 A1 discloses that graphene can be doped with intrinsically doped graphene. WO2021004692 A1 shows how graphene can be doped with oxides on transition metals to increase its electrical conductivity. EP0081004 B1 shows that the electrical conductivity of graphite can be increased by doping with BF3, SiF4, HfF4, TiF4, ZrF4, PF5, NbF5, TaF5, AsF5 or SbF5.

[0003] CN106744888A discloses the production of graphene in a graphene dispersion by adding aluminum fluoride and amines. It is also known from Nakajima, T., Kawaguchi, M., & Watanabe, N. (1981). Ternary intercalation compound of graphite with aluminum fluoride and fluorine. Zeitschrift für Naturforschung B, 36(11), 1419-1423 that aluminum fluoride intercalates into graphite if equimolar amounts of fluorine are present in the gas phase and if sufficiently high temperatures are present. A disadvantage is that such intercalation requires high temperatures, which results in fluorination of the graphite already at temperatures above 300° C., thus impairing conductivity.

[0004] EP 0 212 940 shows that metal chlorides are particularly suitable for intercalation doping if they have a low sublimation or boiling point. EP 0 212 940 therefore uses aluminum chloride, which has a very low sublimation point, to more quickly intercalate other metal chlorides with higher sublimation or boiling points into graphite at lower temperatures.

[0005] Another disadvantage of the prior art is that, as shown by Matsumoto et al. (Matsumoto, K., Minori, D., Takagi, K., & Hagiwara, R. (2014), Expansion of tetrachloroaluminate-graphite intercalation compound by reaction with anhydrous hydrogen fluoride. Carbon, 67, 434-439), the fluorination of graphite intercalated with metal chlorides with anhydrous hydrofluoric acid (HF) leads to the formation of gas in the graphite, resulting in the expansion of the graphite. Similarly, in the case of conductors, this also leads to their expansion and thus their destruction.

[0006] Invention Disclosure

[0007] In contrast, the method according to the invention having the features of the main claim has the advantage that conductor bundles comprising carbon conductors can be produced which have a higher electrical conductivity than in the prior art and are temperature-resistant up to at least 200° C.

[0008] According to a first embodiment, the method features of the main claim result in a final product, and according to the second and third embodiments result in an intermediate product which can be processed by further steps according to the invention to give a final product.

[0009] Advantageous developments and improvements of the method specified in the main claim are possible by means of the measures listed in the dependent claims.

[0010] According to a first embodiment, the intercalation substance is at least one metal fluoride, in particular aluminum fluoride (AlF3), zirconium fluoride (ZrF4), iron fluoride (FeF3), magnesium fluoride (MgF2), wherein the metal of the metal fluoride is selected from one of Groups 2, 4, 5, 6, 8, 10, 11, 12 or 13 of the Periodic Table of the Elements. The advantage of the method according to the first embodiment using a metal fluoride as an intercalation substance is that it requires few process steps and is therefore very simple, since the intercalation substance or dopant is incorporated, which, as a strong Lewis acid, immediately leads to an increase in the electrical conductivity in the conductor material of the conductor strand.

[0011] According to a second embodiment, the embedding substance is at least one metal chloride, metal bromide or metal iodide, in particular aluminum chloride (AlCl3), aluminum bromide (AlBr3), aluminum iodide (AlI3), zirconium chloride (ZrCl4), zirconium bromide (ZrBr4), iron chloride (FeCl3), magnesium chloride (MgCl2), magnesium bromide (MgBr2) or magnesium iodide (MgI2), wherein the metal of the metal chloride, metal bromide or metal iodide is selected from one of Groups 2, 4, 5, 6, 8, 10, 11, 12 or 13 of the Periodic Table of the Elements. The method according to the second embodiment has the advantage that the embedding substance can be embedded in the conductor bundle at a lower temperature than the method according to the first embodiment.

[0012] According to a third embodiment, the intercalating substance is an organic alkali metal, in particular an organic sodium, and most particularly sodium naphthyl (C 10 H8Na), n-pentyl sodium (C5H 11 Na) or benzyl sodium (C7H7Na), organic potassium, especially benzyl potassium (C7H7K) or methyl potassium (CH3K), organic lithium, especially benzyl lithium (C7H7Li), n-hexyl lithium (C6H 13 The method according to the third embodiment has the advantage that the intercalation substance can be embedded into the conductor bundle at a lower temperature than the method according to the first embodiment. In addition, in the method according to the third embodiment, an auxiliary gas such as fluorine or chlorine is not required for embedding. In addition, unlike the other embodiments, the third embodiment causes n-type carbon conductor doping.

[0013] Advantageously, the method according to the first embodiment includes the step of adding gaseous fluorine as an auxiliary gas to the gas phase in the case of embedding in the gas phase of the reactor volume, or providing a liquid phase containing fluoride ions in the case of embedding in the liquid phase of the reactor volume. This accelerates embedding, since the embedding substance can penetrate more quickly into the conductor material of the conductor bundle.

[0014] Furthermore, it is advantageous if the method according to the second embodiment, when embedding in the gas phase of the reactor volume, includes the step of adding gaseous chlorine, bromine, and / or iodine as an auxiliary gas to the reactor volume. In particular, chlorine is preferably added when metal chlorides are used as embedding substances, bromine is preferably added when metal bromides are used as embedding substances, or iodine is preferably added when metal iodides are used as embedding substances. This method enables and / or accelerates embedding, because the embedding substances are only embedded or can be embedded more quickly into the conductor material of the conductor bundle in this manner.

[0015] Advantageously, the method according to the second embodiment further comprises the step of converting the metal chloride, metal bromide, or metal iodide present in the material of the respective carbon conductor into a metal fluoride by treating the conductor strand with a fluorinating agent. The method according to the second embodiment has the advantage over the first embodiment that the intercalating substances, metal chlorides, metal bromides, or metal iodides, can be intercalated into the conductor strand at lower temperatures than the metal fluorides according to the first embodiment. By converting the intercalating substances with the fluorinating agent, the intercalating substances, i.e., metal chlorides, metal bromides, or metal iodides, are subsequently converted in situ into metal fluorides and, thus, into strong Lewis acids, thereby achieving high electrical conductivity in the carbon conductors of the conductor strand. Unlike the method according to the first embodiment, the intercalating substances do not immediately lead to a significant increase in the electrical conductivity of the conductor material. This is achieved only by subsequently converting the intercalating substances in situ with the fluorinating agent. The fluorinating agent may in particular comprise XeF , F , a perfluorinated or fluorinated olefin, such as in particular hexafluorobutene or hexafluoropropylene, a fluorochlorocarbon (FCCW), such as in particular trichlorofluoromethane, a hydrofluorocarbon (FKW), such as in particular perfluorohexane, pentafluorobutane or pentafluoropropane, and / or may in particular be present in the gas phase or enter the gas phase during the fluorination treatment. The treatment with the fluorinating agent is in particular carried out at a temperature below 200° C., thereby preventing the formation of clusters by diffusion from finely distributed, embedded metal chlorides, metal bromides or metal iodides in the carbon conductor, which would lead to a deterioration of the electrical properties of the respective carbon conductor.

[0016] Furthermore, the method according to the third embodiment advantageously further comprises the step of converting the organic alkali metal present in the material of the respective carbon conductor into an alkali metal hydride, particularly lithium hydride (LiH), sodium hydride (NaH), or potassium hydride (KH), by heat treating the conductor strand in a hydrogen atmosphere, particularly at a temperature of 50°C to 250°C. The method according to the third embodiment has the advantage over the first embodiment that the organic alkali metal can be incorporated into the conductor strand as an intercalation substance at lower temperatures than the metal fluoride according to the first embodiment. This intercalation proceeds from a solvent in which the organic alkali metal is dissolved. During the heat treatment, the intercalation substance, i.e., the organic alkali metal, is subsequently converted in situ into an alkali metal hydride and, consequently, a strong Lewis base, by reacting with hydrogen. This achieves high electrical conductivity in the carbon conductor of the conductor strand. Unlike the method according to the first embodiment, the organic alkali metal incorporated as an intercalation substance does not immediately increase the electrical conductivity of the conductor material. This is achieved only by subsequently reacting the intercalation substance with hydrogen via heat treatment in a hydrogen atmosphere, thereby converting it in situ into an alkali metal hydride and an organic residue.

[0017] It is also advantageous if the method according to any of the three embodiments further comprises the step of embedding a hydrophobic substance, in particular an aliphatic compound, an alkane, such as, in particular, undecane, perfluorotripentylamine, perfluoroperhydrofluorene, perfluoroperhydrophenanthrene, or a polysiloxane, such as, in particular, polymethylsiloxane, into the material of the respective carbon conductor, in particular in the gaseous or liquid phase. This prevents water from penetrating into the conductor bundle, making the conductor bundle insensitive to water with respect to its material properties, in particular its electrical conductivity and material resistance.

[0018] Furthermore, the method according to any of the three embodiments advantageously further comprises the step of compressing the conductor bundle to reduce its volume, for example to at least partially reverse the expansion of the conductor bundle that occurs during the embedding of the embedding substance. This further improves the electrical conductivity of the conductor bundle, as the porosity and, therefore, the conductor cross-section are reduced, while the conductor resistance remains unchanged. Furthermore, the flexible conductor bundle can be arranged in the slots of the electric machine with a high slot filling factor, thereby increasing the power of the electric machine.

[0019] If the embedding is carried out in the gas phase of the reactor volume 5, water vapor can also be generated in the reactor volume 5 or added to the reactor volume 5 in the second step of the process. This has the advantage that the expansion of the increased volume of the conductor bundle due to the embedding of the embedding substance is smaller than in a process without the addition of water vapor. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The embodiments of the present invention are described in detail below with reference to the accompanying drawings. In the accompanying drawings:

[0022] Figure 1 shows a schematic diagram of a conductor bundle that can be produced using a method according to an embodiment of the present invention,

[0023] Figure 2 The flow through the reactor volume is shown. Figure 1 Schematic cross section of a conductor bundle,

[0024] Figure 3 shows a schematic diagram embedded in a heat treatment process in a method according to an embodiment of the present invention, and

[0025] Figure 4 A schematic diagram of the in situ conversion to metal fluoride or alkali metal hydride according to the present invention is shown.

[0026] Embodiments of the present invention

[0027] Figure 1 A conductor bundle 1 comprising at least one carbon conductor 3 is schematically shown.

[0028] To carry out the method according to the invention, in a first step at least one conductor bundle 1 is provided or produced as an intermediate product.

[0029] The conductor bundle 1 is a conductor composite, such as a yarn, formed, for example, from a plurality of carbon conductors 3, wherein the carbon conductors 3 can be conductor films, filaments, or fibers. Alternatively, the carbon conductors 3 can be a yarn or a conductor composite having a smaller diameter than the conductor bundle 1. The carbon conductors 3 are made of a carbon material, such as graphite, pyrolytic graphite, graphene, graphyne, and / or carbon nanotubes, or compounds based thereon, such as graphene oxide.

[0030] In the second step of the method, the conductor bundle 1 is introduced into the gas or liquid phase of the reactor volume 5 together with one or more embedding substances 2 ( Figure 2 ). The embedding substance 2 is selected in such a way that it is suitable for embedding into the material of the at least one carbon conductor 3 of the conductor bundle 1 .

[0031] In a third step of the method, the conductor bundle 1 is subjected to a heat treatment, wherein the reactor volume 5 is brought to a process temperature in order to induce intercalation 4, wherein atoms or molecules of the intercalation substance 2 are intercalated into the material of the respective carbon conductor 3, for example, accumulated onto the carbon structure of the carbon conductor 3, for example in the regions between the layers of the multilayer carbon structure.

[0032] Figure 3 The basic sequence of embedding 100 is schematically shown, wherein an example of how the embedding substance 2 is embedded into the intermediate layer 4 of the carbon material, which in this embodiment is formed of graphene, of the at least one carbon conductor 3 of the conductor bundle 1 is shown. Figure 3 Different stages of intercalation 100 are shown, wherein different amounts of intercalation substance 2 are intercalated into the carbon material of the carbon conductor 3 .

[0033] Various configurations are provided for the intercalation substance 2, which are described below as three different embodiments. According to the present invention, the intercalation substance 2 can be one or more metal halides according to the first or second embodiment or one or more organic alkali metals according to the third embodiment.

[0034] I. First embodiment: using metal fluorides, especially aluminum (AlF3)

[0035] In a first embodiment of the method according to the invention, a metal fluoride is used for embedding doping of the conductor strand 1, wherein the metal of the metal fluoride is selected from one of Groups 2, 4, 5, 6, 8, 10, 11, 12, or 13 of the Periodic Table of the Elements. Examples of suitable metal fluorides are aluminum fluoride (AlF3), zirconium fluoride (ZrF4), iron fluoride (FeF3), or magnesium fluoride (MgF2). In particular, amorphous aluminum fluoride (AlF3) is a very strong Lewis acid.

[0036] If the embedding is in the gas phase of the reactor volume 5, gaseous fluorine can additionally be added as auxiliary gas to the gas phase in the second step of the process. If the embedding is in the liquid phase of the reactor volume 5, the liquid phase with the fluoride ions can be selected.

[0037] For embedding, a low vacuum can be provided in the reactor volume 5. The reactor volume 5 is evacuated, for example, to a vacuum of preferably at most 0.1 mbar, particularly preferably at most 0.01 mbar. The walls of the reactor volume 5 are designed to withstand the embedding substance 2 and are made, for example, of nickel or copper.

[0038] In the third step of the method, the reactor volume 5 is heated to a process temperature of at least 750° C. This process temperature is around the sublimation temperature of the metal fluoride, for example above the sublimation temperature.

[0039] The intercalation in the gas phase can be carried out, for example, in such a way that the temperature near the limit point at which sublimation begins oscillates within a fluctuation range of, in particular, ±20° C. to ±40° C. This allows the temperature to fluctuate between sublimation and resublimation of the intercalating substance. Intercalation thus occurs without the formation of more than 10% by volume of metal fluoride crystal clusters in the conductor material.

[0040] It is taken into account that the pressure in the reactor volume 5 varies depending on the temperature. Therefore, the pressure at room temperature is selected so that the pressure at the target temperature allows the metal fluoride to sublime. It is preferably provided that the embedded aluminum fluoride is present predominantly in amorphous form, since in this case the Lewis acid has a high strength.

[0041] The doping according to the first embodiment is particularly stable up to at least 300° C., with moisture having no damaging effect on the doping. Thus, efficient and durable doping is achieved.

[0042] II. Second embodiment: Use of metal chlorides, metal bromides or metal iodides and subsequent in situ conversion to Metal fluorides

[0043] In addition to the above-described first embodiment in which metal fluorides are used as intercalation substances 2, an alternative second embodiment of the method is provided in which at least one metal chloride, metal bromide or metal iodide is intercalated into the carbon conductor 3 as intercalation substance 2, wherein the metal of the metal chloride, metal bromide or metal iodide is selected from one of Groups 2, 4, 5, 6, 8, 10, 11, 12 or 13 of the Periodic Table of the Elements. A further step is then carried out in which the metal chloride, metal bromide and / or metal iodide is converted 200 in situ into a metal fluoride by fluorination. This is in Figure 4 It is schematically shown in FIG.

[0044] Examples of suitable intercalation substances according to the second embodiment are aluminum chloride (AlCl3), aluminum bromide (AlBr3) or aluminum iodide (AlI3), zirconium chloride (ZrCl4), zirconium bromide (ZrBr4), iron chloride (FeCl3), magnesium chloride (MgCl2), magnesium bromide (MgBr2), magnesium iodide (MgI2).

[0045] If the intercalation takes place in the gas phase of the reactor volume 5, then in the second step of the process, gaseous chlorine, bromine or iodine can additionally be added as auxiliary gas to the reactor volume 5. In the case of metal chlorides as intercalation substances 2, chlorine can be added, for example, in the case of metal bromides as intercalation substances 2, bromine can be added, for example, and in the case of metal iodides as intercalation substances 2, iodine can be added, for example.

[0046] If the embedding takes place in the gas phase of the reactor volume 5, water vapor can also be generated in the reactor volume 5 or added to the reactor volume 5 in the second step of the process. In this way, it can be achieved that the volume increase of the conductor bundle or carbon conductor caused by the embedding is smaller than in a process without the addition of water vapor.

[0047] In the fourth step of the method according to the invention, the embedded metal chlorides, metal bromides and / or metal iodides present in the material of the respective carbon conductor 3 are converted in situ into metal fluorides. This is done by treating the conductor bundle 1 with a fluorinating agent. The fluorinating agent is selected, for example, from XeF2, F2, perfluorinated or fluorinated olefins, such as, in particular, hexafluorobutene and hexafluoropropylene, fluorochlorocarbons (FCCs), such as, in particular, trichlorofluoromethane, and hydrofluorocarbons (HFCs), such as, in particular, perfluorohexane, pentafluorobutane or pentafluoropropane. The fluorinating agent is present in the gas phase during the fourth step or enters the gas phase during the fourth step. The treatment with the fluorinating agent is carried out, for example, at a temperature below 200°C.

[0048] Furthermore, for example, the following embodiments are possible:

[0049] Use aluminum chloride (AlCl3), aluminum bromide (AlBr3) or aluminum iodide (AlI3)

[0050] In this embodiment, amorphous aluminum fluoride (AlF3) is generated in situ in the conductor composite in the fourth step. Amorphous aluminum fluoride (AlF3) is comparable in strength as a Lewis acid to antimony fluoride (SbF5) and arsenic fluoride (AsF3).

[0051] In one embodiment, it is provided that aluminum chloride (AlCl 3 ) is fluorinated, wherein in a third step the aluminum chloride (AlCl 3 ) is embedded as embedding substance 2 in the at least one carbon conductor 3 of the conductor bundle 1 .

[0052] The advantage is that aluminum chloride (AlCl 3 ) is very easy to embed into the carbon conductor 3 because its sublimation temperature at 1 bar is very low, about 180° C., compared to about 1260° C. for AlF 3 , and AlCl 3 exists as a tetrahedrally coordinated dimer in the gas phase.

[0053] Another advantage is that AlCl₃ can be converted into AlF₃ in situ at room temperature in the conductor composite using a fluorinating agent. This produces amorphous AlF₃, which has a high strength as a Lewis acid. This increases the conductivity of the carbon conductor 3. Since the AlCl₃ used is essentially converted into AlF₃, the same advantages as those described above are achieved.

[0054] In a second step, aluminum chloride (AlCl3) and the conductor bundle 1 are introduced into a closed reactor volume 5, the walls 6 of which are made, for example, of nickel or copper. The atmosphere in the reactor volume 5 is preferably replaced with an inert gas, such as argon or helium. This is done, in particular, by repeatedly evacuating the reactor volume 5 to a pressure of less than 0.1 mbar and filling the vacuum with the inert gas. Alternatively, the reactor volume 5 can also be rendered inert by a vacuum of preferably less than 0.1 mbar, particularly preferably less than 0.01 mbar. The vacuum increases the partial pressure of AlCl3, thereby promoting doping.

[0055] Subsequently, in a third step, a heat treatment is preferably carried out at 80° C. to 250° C. Here, AlCl 3 is embedded in the conductor bundle 1, ie the conductor composite, as Figure 3 The duration of the heat treatment depends in particular on the thickness of the conductor composite and the diffusion path length of the AlCl 3 determined thereby.

[0056] In the fourth step, the AlCl3 embedded in the conductor bundle 1 is fluorinated by using a fluorinating agent. Figure 4 ), amorphous AlF3 is generated in situ in the conductor bundle 1, for example as shown below by way of example using fluorine as a fluorinating agent for converting aluminum chloride and fluorine into aluminum fluoride and chlorine:

[0057] 2AlCl3+3F2→2AlF3+3Cl2

[0058] The fluorination of AlCl₃ is highly exothermic and can therefore be carried out at room temperature. Due to these very mild fluorination conditions, the AlF₃ formed cannot crystallize and therefore remains amorphous according to the present invention. It is particularly advantageous to embed the AlF₃ in the conductor composite in a finely distributed monomolecular form. This finely distributed monomolecular AlF₃ is a strong electron acceptor and induces p-type doping of the carbon conductor. This allows for a high electrical conductivity of the carbon conductor 3.

[0059] Here, a strongly exothermic fluorination occurs according to the reaction of aluminum chloride and trichlorofluoromethane to form aluminum fluoride and carbon tetrachloride:

[0060] AlCl3+3CFCl3→AlF3+3CCl4

[0061] During storage in CFCl3, CCl4 formed in the conductor composite diffuses into the CFCl3.

[0062] Instead of aluminum chloride (AlCl3) as the embedding substance 2, aluminum bromide or aluminum iodide can be embedded in the carbon conductor or conductor assembly in a third step. To this end, the conductor bundle 1 is heat-treated in the third step, for example at 220°C to 360°C. The aluminum bromide and / or aluminum iodide is embedded in the conductor assembly. The duration of the heat treatment depends, among other things, on the thickness of the conductor assembly and the diffusion path length of the aluminum halide determined thereby. The fluorination of aluminum bromide or aluminum iodide is highly exothermic and can therefore be carried out at room temperature, for example, according to the following reaction for aluminum bromide:

[0063] AlBr3+3CFCl3→AlF3+3CBrCl3

[0064] In this reaction, aluminum bromide and trichlorofluoromethane react to form aluminum fluoride and trichlorobromomethane. The following reaction is carried out with fluorine gas as the fluorinating agent and aluminum bromide as the intercalating species:

[0065] 2AlBr3+3F2→2AlF3+3Br2

[0066] In this reaction, aluminum bromide is converted into aluminum fluoride and bromine gas under the action of fluorine gas.

[0067] Aluminum bromide or aluminum iodide are very easy to embed into carbon conductors because their boiling points of 263°C (AlBr3) and 360°C (AlI3) are very low compared to the sublimation temperature of AlF3, which is about 1260°C.

[0068] The advantage of this embodiment is that the AlF3 doping is stable, particularly up to at least 300°C, and is relatively insensitive to moisture. This overcomes the disadvantages of the prior art that highly efficient intercalating dopants volatilize and evaporate into the surrounding atmosphere at elevated temperatures or decompose upon contact with air by moisture in the air, rendering the doping ineffective.

[0069] Due to these very mild conditions during fluorination, the AlF 3 formed cannot crystallize and therefore, according to the invention, remains amorphous and is embedded in finely distributed form in the conductor composite.

[0070] The conductor composite can then be stored, for example, at 120° C., in order to remove any embedded bromochloroform (boiling point 105° C.) or CCl 4 (boiling point 76.7° C.) from the conductor composite.

[0071] Using zirconium chloride (ZrCl4)

[0072] Another example is doping with zirconium fluoride (ZrF4). Zirconium fluoride (ZrF4) has the advantage that it is one of the strongest Lewis acids when it exists in an amorphous form.

[0073] In a second step, ZrCl4 and the conductor bundle 1 are introduced into a reactor volume 5, the walls 6 of which are made, for example, of nickel or copper. The atmosphere in the reactor volume 5 is exchanged for an inert gas, such as argon or helium. This is preferably done by repeatedly evacuating the reactor volume to a pressure of 0.1 mbar and then breaking the vacuum with the inert gas. Alternatively, the reactor volume 5 can be rendered inert by a vacuum of preferably less than 0.1 mbar, particularly preferably less than 0.01 mbar. The applied vacuum lowers the sublimation temperature and increases the partial pressure of ZrCl4, thereby promoting doping. Furthermore, the addition of chlorine can accelerate intercalation. This can be done, for example, by adding gold chloride (AuCl3) or gold chloride monohydrate (AuCl3·H2O). Gold chloride monohydrate loses its water of crystallization above 100°C. Both types of gold chloride decompose above 254°C at a pressure of 1 bar, releasing chlorine gas.

[0074] In the third step, a heat treatment is preferably carried out at 290° C. to 450° C. In this process, the ZrCl 4 is embedded in the conductor composite. The duration of the heat treatment depends in particular on the thickness of the conductor composite and the diffusion path length of the ZrCl 4 determined thereby.

[0075] In the fourth step, the reaction is carried out with a fluorinating agent. This can be a perfluorinated or fluorinated olefin, such as in particular hexafluorobutene and hexafluoropropylene, a fluorochlorocarbon (FCCW), such as in particular trichlorofluoromethane CFCl (boiling point 23.7° C.) and dichlorodifluoromethane CF Cl , a hydrofluorocarbon (FKW), such as in particular perfluorohexane, pentafluorobutane or pentafluoropropane or other suitable fluorine compounds, such as XeF or F .

[0076] In the fourth step, the zirconium chloride (ZrCl4) embedded in the conductor bundle 1 is fluorinated by a fluorinating agent, and amorphous zirconium fluoride (ZrF4) is generated in situ in the conductor bundle 1. This is exemplified by the following reaction of converting zirconium chloride and fluorine gas into zirconium fluoride and chlorine gas using fluorine gas as the fluorinating agent:

[0077] ZrCl4+2F2→ZrF4+2Cl2

[0078] The fluorination of ZrCl₄ is highly exothermic and can therefore be carried out at room temperature. Due to these very mild conditions during fluorination, the ZrF₄ formed cannot crystallize and therefore, according to the present invention, remains amorphous and, in a particularly advantageous manner, is embedded in the conductor composite in a finely distributed monomolecular form. This allows for a high electrical conductivity of the carbon conductor 3.

[0079] In another step, the conductor composite is stored above liquid CFCl3 so that the conductor composite is surrounded by a high concentration of gaseous CFCl3 of >30% by volume. Here, a strongly exothermic fluorination occurs, which corresponds to the reaction of zirconium chloride and trichlorofluoromethane to form zirconium fluoride and carbon tetrachloride.

[0080] ZrCl4+4CFCl3→ZrF4+4CCl4

[0081] The conductor assembly can then be stored, for example, at 120° C., in order to remove any traces of embedded carbon tetrachloride (boiling point 76.7° C.) which are still present and which have not diffused into the trichlorofluoromethane, from the conductor assembly.

[0082] Using ferric chloride (FeCl3)

[0083] Iron fluoride (FeF 3 ) can also be used for doping, since iron fluoride (FeF 3 ) is a strong Lewis acid when present in amorphous or monomolecular form. For this purpose, iron chloride (FeCl 3 ) is used as the intercalation substance 2 .

[0084] In the second step, ferric chloride (FeCl3) and a conductor bundle are introduced into the reactor volume 5, wherein the walls 6 of the reactor volume 5 are preferably made of nickel or copper. The atmosphere in the reactor volume 5 is exchanged for an inert gas, such as argon or helium. This is preferably done by repeatedly evacuating to a pressure of less than 0.1 mbar and then filling the vacuum with the inert gas accordingly. Alternatively, the reactor volume 5 can be rendered inert by a vacuum of preferably less than 0.1 mbar, particularly preferably less than 0.01 mbar. The vacuum increases the volatility of the FeCl3, thereby promoting doping. Furthermore, the addition of chlorine can accelerate intercalation. This can be done, for example, by adding gold chloride (AuCl3) or gold chloride monohydrate (AuCl3·H2O). Gold chloride monohydrate loses its water of crystallization above 100°C. Both types of gold chloride decompose and eliminate chlorine at 1 bar above 254°C and at 0.1 mbar even above 65°C.

[0085] In the third step, a heat treatment is preferably carried out at 120° C. to 300° C. In this process, the FeCl 3 is embedded in the conductor bundle 1 . The duration of the heat treatment depends in particular on the thickness of the conductor bundle 1 and the diffusion path length of the FeCl 3 determined thereby.

[0086] In the fourth step, the treatment is carried out with a fluorinating agent. This can be a perfluorinated or fluorinated olefin, such as in particular hexafluorobutene and hexafluoropropylene, a fluorochlorocarbon (FCCW), such as in particular trichlorofluoromethane CFCl3 (onset boiling 23.7°C) and dichlorodifluoromethane CF2Cl2, a hydrofluorocarbon (FKW), such as in particular perfluorohexane, pentafluorobutane or pentafluoropropane or other suitable fluorine compounds, such as XeF2 or F2.

[0087] In the fourth step, amorphous FeF3 is generated in situ in the conductor composite by fluorinating the FeCl3 embedded in the conductor bundle 1 with a fluorinating agent. In particular, this is done with hydrofluoric acid, as shown for example by the following reaction for converting iron chloride and hydrofluoric acid into iron fluoride and hydrochloric acid:

[0088] FeCl 3(s) +3HF (g) →FeF 3(s) +3HCl (g)

[0089] Alternatively, fluorine can also be used as fluorinating agent (converting iron chloride and fluorine into iron fluoride and chlorine), whereby only half the gas, based on FeCl 3 , is still formed:

[0090] 2FeCl 3(s) +3F 2(g) →2FeF 3(s) +3Cl 2(g)

[0091] It is even more advantageous to carry out the fluorination with trichlorofluoromethane (CFCl3) and dichlorodifluoromethane (CF2Cl2), since no gas is formed here, but a liquid is formed with carbon tetrachloride (CCl4), which can be removed from the conductor by diffusion without swelling. This is shown by way of example in the following reaction for the conversion of iron chloride and dichlorodifluoromethane into iron fluoride and carbon tetrachloride using CF2Cl2 as an example:

[0092] 2FeCl 3(s) +3CF2Cl 2(g) →2FeF 3(s) +3CCl 4(l)

[0093] Fluorination with trichlorofluoromethane (CFCl 3 ) can be carried out, for example, by immersing the conductor composite in CFCl 3 . The strongly exothermic fluorination proceeds according to the following reaction of ferric chloride and trichlorofluoromethane to ferric fluoride and carbon tetrachloride, especially when water is excluded:

[0094] FeCl 3(s) +3CFCl 3(l) →FeF 3(s) +3CCl4(l)

[0095] The conductor assembly can then be stored, for example, at 65°C to remove any remaining traces of embedded carbon tetrachloride (boiling point 76.7°C) that have not diffused out of the conductor assembly due to the immersion in chloroform. The fluorination of FeCl3 is highly exothermic and can therefore be carried out at room temperature. Due to these very mild conditions during fluorination, the FeF3 formed cannot crystallize and therefore, according to the invention, remains amorphous and, in a particularly advantageous manner, is embedded in the conductor bundle 1 in a finely distributed monomolecular form. This allows for a high electrical conductivity of the carbon conductor 3.

[0096] In the second step, instead of iron(III) chloride FeCl 3 , iron(II) chloride (FeCl 2 ) and chlorine (for example in the form of gold chloride) can be introduced into the reactor volume 5 . Here, FeCl 3 is formed by converting iron(II) chloride and gold chloride into iron(III) chloride and gold according to the following reaction:

[0097] 3FeCl 2(s) +AuCl 3(s) →3FeCl 3(s) +Au (s)

[0098] In a third step, the iron(III) chloride is then intercalated into the carbon conductor.

[0099] Use magnesium chloride, magnesium bromide, or magnesium iodide

[0100] In this exemplary embodiment, amorphous magnesium fluoride MgF 2 is produced in situ in the conductor composite in a fourth step.

[0101] Furthermore, in the third step, magnesium chloride (MgCl2), magnesium bromide (MgBr2), or magnesium iodide (MgI2) is embedded in the conductor composite. Subsequently, in the fourth step, the magnesium chloride (MgCl2), magnesium bromide (MgBr2), or magnesium iodide (MgI2) is fluorinated with a fluorinating agent, as shown in the following reaction using magnesium chloride as an example and fluorine gas as the fluorinating agent.

[0102] MgCl2+F2→MgF2+Cl2

[0103] Magnesium chloride (MgCl2), magnesium bromide (MgBr2), or magnesium iodide (MgI2) are very easy to incorporate into conductor composites with carbon conductors because their melting temperatures of 712°C (MgCl2), 711°C (MgBr2), and 637°C (MgI2) are significantly lower than the sublimation temperature of MgF2, which is approximately 1256°C. Furthermore, chlorine gas, in particular, allows incorporation into the conductor composite at temperatures below the melting temperature of the metal halides. Another advantage is that magnesium chloride (MgCl2), magnesium bromide (MgBr2), or magnesium iodide (MgI2) can be converted into MgF2 in situ at room temperature in the conductor composite using a fluorinating agent. This forms amorphous MgF2, which is a strong Lewis acid. Another advantage is that doping with MgF2 is stable, particularly up to at least 350°C, and is insensitive to moisture.

[0104] By doping MgF2 with a fluoride of the formula MF3, the acidity of MgF2 can be increased to the strength of antimony fluoride (SbF5) and arsenic fluoride (AsF3). This is achieved according to the invention by incorporating at least one other halide of the formula MX3 (wherein M is a metal in the oxidation state +3, such as iron (Fe), aluminum (Al), vanadium (V), chromium (Cr), indium (In), and gallium (Ga), and where X is chlorine, bromine, and / or iodine) in addition to the magnesium halide into the conductor composite and likewise converting it into a fluoride in a fluorination step, for example, in the case of magnesium chloride according to the following reaction:

[0105] 15MgCl2+VCl3+2AlCl3+FeCl3+21F2→15MgF2+VF3+2AlF3+FeF3+21Cl2

[0106] III. Third embodiment: Use of organic alkali metals and subsequent in situ conversion to alkali metal hydrides

[0107] In a third embodiment, the intercalating species is an organic alkali metal, such as an organic sodium, in particular sodium naphthyl (C 10 H8Na), n-pentyl sodium (C5H 11 Alternatively, organic potassium, in particular benzyl potassium (C7H7K) or methyl potassium (CH3K), or organic lithium, in particular benzyl lithium (C7H7Li), n-hexyl lithium (C6H 13 Li), n-butyllithium (C4H9Li) and phenyllithium (C6H5Li).

[0108] In a second step, the conductor bundle 1 and the organic alkali metal dissolved in a solvent are introduced into the reactor volume 5. In this process, the conductor bundle 1 is immersed in the solvent.

[0109] In the third step, the conductor bundle 1 and the organic alkali metal dissolved in the solvent are heat-treated at a mild temperature of room temperature to 200° C., thereby intercalating the organic alkali metal into the carbon conductor of the conductor bundle.

[0110] In the fourth step, similar to the second embodiment, the organic alkali metal present in the material of the respective carbon conductor is converted in situ into an alkali metal hydride, such as lithium hydride (LiH), sodium hydride (NaH), or potassium hydride (KH). Unlike the second embodiment, this is carried out by heat treating the conductor bundle 1 in a hydrogen atmosphere, for example at a temperature of 50° C. to 250° C.

[0111] After producing the conductor bundle according to any of the three embodiments, a fifth step can be provided: embedding a hydrophobic substance into the material of the carbon conductor or conductor bundle 1, for example in the gas phase or liquid phase. The hydrophobic substance can be, for example, an aliphatic compound, an alkane, such as, in particular, undecane, perfluorotripentylamine, perfluoroperhydrofluorene, perfluoroperhydrophenanthrene, or a polysiloxane, such as, in particular, polymethylsiloxane.

[0112] Furthermore, it is provided that after the production of the one or more carbon conductors or the conductor bundle according to any of the three embodiments, the conductor bundle 1 is compressed.

Claims

1. A method for producing an electrically conductive conductor bundle (1) comprising at least one carbon conductor (3), comprising the following steps: a) producing or providing a conductor bundle (1) as an intermediate product comprising at least one carbon conductor (3), b) introducing a conductor bundle (1) and one or more embedding substances (2) into the gaseous or liquid phase of the reactor volume (5), wherein the embedding substances are suitable for embedding into the material of the at least one carbon conductor (3) of the conductor bundle (1), and c) subjecting the conductor bundle (1) to a heat treatment, wherein the reactor volume (5) is brought to a process temperature in order to induce intercalation (4), wherein atoms or molecules of the intercalation substance (2) are intercalated in the regions between the layers in the form of a multilayer carbon structure of the respective carbon conductor (3), Characterized in that the intercalation substance (2) is aluminum chloride (AlCl3), zirconium chloride (ZrCl4), zirconium bromide (ZrBr4), magnesium chloride (MgCl2), magnesium bromide (MgBr2), magnesium iodide (MgI2), aluminum bromide (AlBr3) or aluminum iodide (AlI3), and The method further comprises the following steps: d) converting metal chlorides, metal bromides or metal iodides present in the material of the respective carbon conductor into metal fluorides by treating the conductor strand (1) with a fluorinating agent, wherein the treatment with the fluorinating agent is carried out at a temperature below 200° C., The fluorinating agent comprises a perfluorinated or fluorinated olefin, a fluorochlorocarbon (FCKW), a hydrofluorocarbon (FKW), or another fluorine compound selected from XeF2 or F2.

2. The method according to claim 1, characterized in that The fluorinating agent comprises hexafluorobutene, hexafluoropropylene, trichlorofluoromethane (CFCl3), dichlorodifluoromethane (CF2Cl2), perfluorohexane, pentafluorobutane or pentafluoropropane, and / or the fluorinating agent is present in the gas phase or enters the gas phase during processing.

3. The method according to any one of claims 1 to 2, characterized in that The method comprises the following steps with embedding in the gas phase of the reactor volume in step b): adding gaseous chlorine, bromine and / or iodine to the reactor volume, and - addition of chlorine in the case of metal chlorides as intercalating species (2), - addition of bromine in the case of metal bromides as intercalating species (2), - Addition of iodine in the case of metal iodides as intercalating species (2).

4. The method according to any one of claims 1 to 2, characterized in that The method further comprises the following steps: e) embedding the hydrophobic substance into the material of the respective carbon conductor in the form of gas phase or liquid phase.

5. The method according to any one of claims 1 to 2, characterized in that The method further comprises the following steps: Compress the conductor bundle.

6. The method according to claim 1, characterized in that The carbon conductor includes graphite, pyrolytic graphite, graphene, graphyne and / or carbon nanotubes.

7. The method according to claim 4, characterized in that The hydrophobic substance is an aliphatic compound.

8. The method according to claim 4, characterized in that The hydrophobic substance is an alkane.

9. The method according to claim 4, characterized in that The hydrophobic substance is undecane, perfluorotripentylamine, perfluoroperhydrofluorene, perfluoroperhydrophenanthrene or polysiloxane.

10. The method according to claim 4, characterized in that The hydrophobic substance is polymethylsiloxane.

11. A method for producing an electrically conductive conductor bundle (1) comprising at least one carbon conductor (3), comprising the steps of: a) producing or providing a conductor bundle (1) as an intermediate product comprising at least one carbon conductor (3), b) introducing a conductor bundle (1) and one or more embedding substances (2) into the liquid phase of the reactor volume (5), wherein the embedding substances are suitable for embedding into the material of the at least one carbon conductor (3) of the conductor bundle (1), and c) subjecting the conductor bundle (1) to a heat treatment, wherein the reactor volume (5) is brought to a process temperature in order to induce intercalation (4), wherein atoms or molecules of the intercalation substance (2) are intercalated in the regions between the layers in the form of a multilayer carbon structure of the respective carbon conductor (3), Characterized in that the intercalation substance (2) is n-pentyl sodium (C5H 11 Na), benzyl sodium (C7H7Na), benzyl potassium (C7H7K), methyl potassium (CH3K), benzyl lithium (C7H7Li), n-hexyl lithium (C6H 13 Li), n-butyllithium (C4H9Li) or phenyllithium (C6H5Li), and The method further comprises the following steps: d) The organic alkali metal present in the material of the respective carbon conductor is converted into an alkali metal hydride by heat-treating the conductor bundle (1) in a hydrogen atmosphere.

12. The method according to claim 11, characterized in that The conductor bundle (1) is heat-treated at a temperature of 50°C to 250°C in a hydrogen atmosphere.

13. The method according to any one of claims 11 to 12, characterized in that The method further comprises the following steps: e) embedding the hydrophobic substance into the material of the respective carbon conductor in the form of gas phase or liquid phase.

14. The method according to any one of claims 11 to 12, characterized in that The method further comprises the following steps: Compress the conductor bundle.

15. The method according to claim 11, characterized in that The carbon conductor includes graphite, pyrolytic graphite, graphene, graphyne and / or carbon nanotubes.

16. The method according to claim 13, characterized in that The hydrophobic substance is an aliphatic compound.

17. The method according to claim 13, wherein The hydrophobic substance is an alkane.

18. The method according to claim 13, characterized in that The hydrophobic substance is undecane, perfluorotripentylamine, perfluoroperhydrofluorene, perfluoroperhydrophenanthrene or polysiloxane.

19. The method according to claim 13, wherein The hydrophobic substance is polymethylsiloxane.

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