Electrically conductive plastic and use thereof

Abstract

The invention relates to an electrically conductive plastic and the use thereof.

Description

[0001] Electrically conductive plastic and its use

[0002] The present invention relates to the technical field of conductive polymers.

[0003] In particular, the present invention relates to an electrically conductive plastic as well as its diverse uses and a process for its production.

[0004] Furthermore, the present invention relates to a bipolar plate, a film, an intermediate product and a molded body which contain the electrically conductive plastic.

[0005] Finally, the invention relates to a method for producing a bipolar plate.

[0006] Conductive polymers are used for a wide range of applications, particularly for electrochemical reactors, but also for antistatic coatings and fabrics.

[0007] The most important area of ​​application, however, is electrochemical reactors, particularly in fuel cells and flow reactors, such as a redox flow battery, which consists of repeating components that are stacked on top of each other to form a so-called stack.

[0008] The most important repeating components of electrochemical reactors are ion-conductive membranes and carbon-containing or carbon-based electrodes, through which the reactants are distributed. These can be designed, in particular, as gas diffusion layers in fuel cells and graphite fleeces in flow batteries. Contact between the individual cells is achieved via so-called bipolar plates (BPPs), which conduct the current from cell to cell. Furthermore, the BPP fluidically separates the individual cells from each other. While flat bipolar plates are used in flow reactors, bipolar plates for fuel cells are equipped with a gas distribution geometry, the so-called flow field, through which the reaction media hydrogen and oxygen are fed into the individual cells.

[0009] Bipolar plates can be made of metal, but this is problematic for many applications due to their susceptibility to corrosion. Although metallic materials are characterized by their good mechanical stability and good electrical conductivity, their low chemical resistance requires complex coatings, especially for use in fuel cells.

[0010] For this reason, bipolar plates often consist of a plastic-carbon mixture, which is processed into a compound using processes established in the plastics industry, for example the powder-to-roll process according to WO 2015 / 007544 A1.

[0011] In addition to production according to WO 2015 / 007544 A1, the production of bipolar plates by extrusion and subsequent injection molding is also possible.

[0012] Furthermore, the carbon particles can be embedded in a thermosetting matrix, which is formed into bipolar plates, in particular by hot pressing.

[0013] The bipolar plates made from the electrically conductive polymer compound can be used, among other things, in electrical energy storage devices, in particular in redox flow batteries, in fuel cells as well as in other electrochemical reactors, thermal reactors and flow reactors, in particular in electrolyzers.

[0014] A bipolar plate (BPP) is a multifunctional electrically conductive body that fluidically separates two cells in, for example, a fuel cell or a redox flow battery, conducts the current from one cell to the other across its entire surface and, in the case of the fuel cell, ensures the supply of media via an integrated fluid distribution structure, the so-called flow field.

[0015] Due to the required high chemical resistance, bipolar plates are advantageously manufactured from polymer compounds, with additives, particularly in the form of carbon, being used to adjust the electrical conductivity. The electrical conductivity of the BPP, in turn, directly influences the achievable performance of the electrochemical system. In addition to graphite as the main filler, the state of the art uses so-called conductive carbon black as an additive to adjust the electrical conductivity. This carbon material has a high external specific surface area, but with few exceptions, lacks a significant pore system and therefore has a low internal specific surface area. The nm-scale carbon black intercalates between the pm-scale graphite particles and increases the formation of electrically conductive pathways within the plate.

[0016] Other carbon materials such as expandable graphite, i.e. graphite with a particularly large surface area, carbon fibers and carbon nanotubes are also being investigated as additives; see Renato A. Antunes, Mara CL de Oliveira, Gerhard Ett, Volkmar Ett, Carbon materials in composite bipolar plates for polymer electrolyte membrane fuel cells: A review of the main challenges to improve electrical performance, Journal of Power Sources (196) 6, 2011 , 2945-2961 , ISSN 0378-7753, DOI:10.1016 / j.jpowsour.2010.12.041.

[0017] The addition of conductive carbon black to a polymer compound increases the electrical conductivity and also improves the mechanical properties of the compound. On the other hand, the addition of the nm-scale carbon black particles increases the viscosity of the polymer melt, which drastically changes the processing properties.

[0018] Increasing electrical conductivity by adding conductive carbon black to a polymer compound is very efficient, but only possible to a limited extent, as too high a concentration impairs the mechanical properties of the bipolar plate. Reducing the size of the carbon particles is also only possible within narrow limits, as graphite's lubricating properties limit its ability to be ground to a limited extent with reasonable effort. Carbon nanotubes offer great potential for increasing the electrical conductivity of compounds, but are very costly to produce.

[0019] Carbon blacks, i.e., not significantly micro- or mesoporous carbon materials, are also known as components of gas diffusion layers, as described in Glora, M., et. AL; Integration of carbon aerogels in PEM fuel cells; Journal of Non-Crystalline Solids, Volume 285; 2001 ; https: / / doi.org / 10.1016 / S0022-3093(01 )00468-9. The procedure here is that carbon-based papers are first produced and then provided with microporous carbon-based coatings. Furthermore, EP 1 246 289 A2 discloses the use of carbon blacks as carbon materials. Graphite can also be used in gas diffusion layers, as in WO 2023 / 025516 A2.The gas diffusion layers can also be created directly with carbon material, preferably carbon black, and a polymer, wherein the carbon material is responsible for the electrical conductivity of the resulting composite material, as disclosed, for example, in EP 1 472 751 A2, US 2007 / 190398 A1 or US 8,455,155 B1.

[0020] US 10 629 918 B1 discloses the use of carbon materials with pore sizes down to 1 pm in an environment with a catalytically coated polymer electrolyte membrane.

[0021] Activated carbons are known in the literature as coatings for metallic bipolar plates, whereby this layer supports, for example, the construction of supercapacitors, see in particular Xiaojuan Liu, Tao Wu, Zengxin Dai, Keran Tao, Yong Shi, Chuang Peng, Xiaohang Zhou, George Z. Chen, Bipolarly stacked electrolyser for energy and space efficient fabrication of supercapacitor electrodes, Journal of Power Sources 307 (2016), pp. 208-213, D0l:10.1016 / j.jpowsour.2016.01.006.t.

[0022] The flow channels of a metallic bipolar plate can be coated hydrophilically or hydrophobically. A hydrophilic coating can include a carbon coating that is plasma-treated to increase its hydrophilic properties and can be amorphous or graphitic, or a mixture of both. The hydrophobic coating can contain carbon nanotubes—like the microporous coating of the gas diffusion layer—as described in US 2014 / 113217 A1. Alternatively, US 2010 / 028749 A1 describes a graphene-containing coating with optional plasma activation. The coatings can be chemically activated or contain nitrogen or oxygen atoms, as disclosed in US 2010 / 028743 A1. Coatings with carbon materials do not affect the conductivity of the bipolar plate but serve other functions.

[0023] The production of an electrically conductive plastic from a polymer with a mixture of graphite or another inorganic filler, carbon black, and activated carbon for use as a metal-halogen battery electrode is described in EP 0 190 772 B1. The electrode can also be a bipolar plate. The activated carbons used can be obtained by steam activation or chemical activation. Activated carbons produced by steam activation and chemical activation are characterized by a pore system primarily characterized by micropores. Furthermore, carbon black must always be present alongside the activated carbon.

[0024] US 2018 / 006314 A1 describes the production of a bipolar plate by impregnating a porous solid structure, for example, an optionally compressed particle bed, with a thermoplastic resin, i.e., encapsulating it in the resin. The porous solid structure can contain a porous structure, such as activated carbon, as a material. For the bipolar plate to be conductive, the solid must be present as a conductive structure, for example, as a bed.

[0025] CA 2 730 169 C describes the production of bipolar plates using carbon materials loaded with metal oxides. The carbon materials are incorporated into a polymer matrix. The material is then carbonized and optionally activated. The resulting material is carbonized and therefore necessarily brittle; therefore, gas-tight media separation can hardly be reliably guaranteed, especially when such a bipolar plate is incorporated into a stack, which is always associated with mechanical stresses, as long as the material thicknesses remain within technically reasonable limits.

[0026] The conductive polymer materials known to date for the production of components for batteries and electrochemical reactors have the particular disadvantage of being either very costly or degrading the mechanical properties of the resulting compound. It is particularly important that polymer compounds exhibit a certain degree of flexibility and are easy to process, as they are subject to high mechanical stress when used, for example, as bipolar plates in stacks.

[0027] In addition to the aforementioned possibilities, there have also been other attempts to produce conductive polymer compounds.

[0028] Porous, gas-activated carbon, with and without metal addition, is used as a catalyst in catalytically active layers of porous fuel cell electrodes. The polymers can be used as a support material, as described in WO 02 / 09214 A1. Alternatively, according to DE 10 2007 010 350 A1, activated carbon or carbon spheres can be fixed in a textile support matrix, for example, and used as an electrode. US 10 439 246 B1 describes a porous electrode for use in redox flow batteries that simultaneously fulfills the functions of both a bipolar plate and a felt electrode. The complex porous electrode comprises, among other things, a porous conductor and a binder. The porous conductor can comprise a first conductive material with a porous structure and a second conductive material, which can consist of or contain mesoporous carbon.The binder can contain or consist of, for example, polytetrafluoroethylene (PTFE), carboxymethylcellulose (CMC), polyvinyl alcohol (PVA), or polyethylene (PE). The binder can be mixed with the porous conductor and then formed into a film by rolling and subsequent drying.

[0029] Furthermore, it is also possible to construct membrane electrodes for fuel cells based on carbon-coated nanowires. The interstices between the wires form a mesoporous network. However, this process is very complex and therefore hardly feasible on a large-scale.

[0030] An object of the present invention is to avoid, or at least mitigate, the aforementioned disadvantages associated with the prior art.

[0031] In particular, it is an object of the present invention to provide a conductive plastic which is cost-effective, reproducible and producible on an industrial scale.

[0032] A further object of the present invention is to provide a conductive plastic that can be processed easily and by means of methods customary in plastics processing.

[0033] Furthermore, it is an object of the present invention to provide materials made of a cost-effective, electrically conductive plastic which have improved mechanical and electrical properties compared to the known materials of the prior art.

[0034] The subject matter of the present invention—according to a first aspect of the present invention—is thus an electrically conductive plastic according to claim 1; further advantageous embodiments of this aspect of the invention are the subject matter of the relevant subclaims.

[0035] A further subject matter of the present invention - according to a second aspect of the present invention - is the use of an electrically conductive plastic according to claim 25.

[0036] Yet another object of the present invention - according to a third aspect of the present invention - is the use of an electrically conductive plastic according to claim 26.

[0037] Furthermore, the present invention - according to a fourth aspect of the present invention - relates to the use of an electrically conductive plastic according to claim 27.

[0038] A further subject matter of the present invention - according to a fifth aspect of the present invention - is the use of an electrically conductive plastic according to claim 28.

[0039] A further subject matter of the present invention - according to a sixth aspect of the present invention - is the use of an electrically conductive plastic according to claim 29.

[0040] A further subject matter of the present invention - according to a seventh aspect of the present invention - is a process for producing an electrically conductive plastic according to claim 30.

[0041] A further subject matter of the present invention - according to an eighth aspect of the present invention - is a bipolar plate according to claim 31.

[0042] Yet another subject matter of the present invention - according to a ninth aspect of the present invention - is a film according to claim 32.

[0043] Furthermore, the present invention - according to a tenth aspect of the present invention - provides an intermediate product according to claim 33. Yet another subject of the present invention - according to an eleventh aspect of the present invention - is a shaped body according to claim 34.

[0044] Finally, the subject of the present invention - according to a twelfth aspect of the present invention - is a method for producing a bipolar plate according to claim 35.

[0045] It goes without saying that special features, characteristics, configurations and embodiments as well as advantages or the like which are explained below - for the purpose of avoiding unnecessary repetition - only with regard to one aspect of the invention, naturally apply accordingly with regard to the other aspects of the invention without this requiring express mention.

[0046] Furthermore, it should be noted that with all relative or percentage quantities, especially those based on weight, mentioned below, these must be selected by the person skilled in the art within the scope of the present invention in such a way that the sum of the ingredients, additives, auxiliaries, or the like always results in 100% or 100% by weight. However, this is self-evident to the person skilled in the art.

[0047] In addition, all parameter specifications or similar mentioned below can in principle be determined or ascertained using standardized or explicitly specified determination methods or using determination procedures that are familiar to the person skilled in the art.

[0048] With this in mind, the subject matter of the present invention is explained in more detail below.

[0049] The subject matter of the present invention - according to a first aspect of the present invention - is an electrically conductive plastic, in particular an electrically conductive polymer compound, wherein the plastic, in particular the polymer compound, contains mesoporous electrically conductive particles.

[0050] As the applicants have surprisingly discovered, the use of mesoporous particles makes it possible to obtain electrically conductive plastics that exhibit significantly improved electrical and mechanical properties compared to known electrically conductive plastics, particularly compared to electrically conductive plastics containing carbon-based conductive materials. The conductive particles commonly used in the prior art—to the extent that they are porous at all—are merely microporous.

[0051] By using mesoporous materials, in particular mesoporous particles, in the plastic according to the invention, the mechanical and electrical properties are significantly improved, as already explained above.

[0052] In addition, the electrically conductive plastic according to the invention can be processed excellently, since its melts or liquid precursors have a comparatively low viscosity due to the use of usually pm-scale mesoporous particles.

[0053] The advantageous properties of the electrically conductive plastic according to the invention are attributable—without being bound by this theory—to the use of mesoporous particles, since the use of mesoporous particles significantly improves the bonding of the polymer to the particles compared to non-porous or microporous particles. The mesopores on the outer shell of the particles are so large that the polymer adheres better there or becomes entangled in the pores. This improved adhesion increases the contact area between the polymer and the particles, while also improving the current transfer between neighboring particles. As a result, a material with improved mechanical and electrical properties can be obtained.

[0054] Mesoporosity improves the wetting properties of the conductive particles, especially carbon materials, for the polymer of the plastic. The affinity of mesoporous structures for nonpolar organic fluids and solids, an expression of the wetting property, is expressed by the oil adsorption number (OAN, ISO 4656). Like oil, polymers, especially polyolefins, consist of CH compounds, which means they have a higher or lower affinity for the incorporated particles, especially the carbon. The improved OAN simplifies compound production by facilitating dispersion and achieving a homogeneous distribution of the particles in the binding plastic, thus enabling increased conductivity and improved mechanical properties of the final product with the same particle content.

[0055] By using mesoporous electrically conductive particles, it is possible to significantly increase the conductivity of electrically conductive plastics or polymer compounds and bipolar plates made from them using a material that is significantly more cost-effective to produce than special carbon materials, such as carbon nanotubes.

[0056] The terms "porosity" and "pores," in particular "porosity" and "mesopores," are understood in the context of the present invention to refer to the system of cavities within a continuous solid and on the outer surface of a continuous solid, in particular a particle. In particular, cavities between solid particles are not considered pores in the context of the invention. For the purposes of this invention, mesoporous particles are considered to be, in particular, primary particles and aggregates of mesoporous materials, but not their agglomerates.

[0057] As for pores and their classification, they are usually classified according to their pore size as follows:

[0058] Micropores with a pore size of less than 2 nm,

[0059] Mesopores with a pore size in the range of 2 to 50 nm, and

[0060] Macropores with a pore size of over 50 nm.

[0061] Mesoporous materials or particles have mesopores, although the materials or particles can also have pores with different pore sizes.

[0062] The plastic according to the invention as such has no continuous pores, i.e., cavities extending through the plastic. The plastic according to the invention is thus impermeable, particularly gas-tight.

[0063] In the context of the present invention, electrically conductive means a compound or a material which has an electrical conductivity of at least 1 • 10'11 S • m -1 Within the scope of the present invention, it is preferred if the electrically conductive plastic has an electrical conductivity of at least 1 • 10' 4 S • m' 1 , especially 1 • 10' 2 S • m' 1 , preferably 1 S • m' 1 Particularly good results are obtained if the electrically conductive plastic has an electrical conductivity of at least 1 • 10' at 20 °C 2 S • m' 1 , especially 1 • 10 3 S • m' 1 , in particular, plastics that exhibit the latter conductivities can be used to produce particularly high-performance bipolar plates.

[0064] In the context of the present invention, a plastic or a polymer compound is understood to mean in particular a polymeric material which, in addition to a polymer or polymer blend, contains further additives such as fillers, plasticizers, UV stabilizers, etc.

[0065] In the context of the present invention, it is usually provided that the mesoporous particles are selected from the group of carbon-containing materials, metal-organic frameworks (MOFs), covalent organic frameworks (COFs), core-shell structured mesoporous materials, in particular core-shell nanoparticles (CSN), metal oxides, nitrides, carbides, porous polymers and mixtures thereof.

[0066] Particularly good results are obtained in the context of the present invention when the mesoporous particles are selected from the group of carbon-containing materials, covalent organic frameworks, metal oxides, carbides and mixtures thereof.

[0067] In the context of the present invention, it is particularly preferred if the mesoporous particles are carbon-containing materials.

[0068] In the context of the present invention, it has proven particularly useful if the carbon-containing material is a carbon gel and / or activated carbon, preferably a carbon gel. In the context of the present invention, a carbon gel is understood to mean a carbon-containing material obtained by gel synthesis, wherein the gel is carbonized and optionally activated. In the context of this invention, carbon gels are in particular carbon aerogels, carbon xerogels and carbon cryogels. In the context of the present invention, it is further preferred if the carbon-containing material is obtainable by activation of carbonized materials, gel synthesis, in particular sol-gel synthesis, ionothermal carbons synthesis, advanced ionothermal carbons synthesis, hard templating or soft templating.The carbonaceous material is preferably obtainable by gel synthesis, in particular sol-gel synthesis, ionothermal carbon synthesis, or advanced ionothermal carbon synthesis. Within the scope of the invention, the activation of carbonized materials refers in particular to the activation of previously carbonized biogenic materials, in particular biomass, for example based on wood or straw, but also other suitable materials, such as scrap tires.

[0069] According to a preferred embodiment of the present invention, the carbon material is obtainable by gel synthesis, in particular sol-gel synthesis.

[0070] According to a further preferred embodiment of the present invention, the carbonaceous material is obtainable by activation of carbonized materials, ionothermal carbons synthesis, advanced ionothermal carbons synthesis, hard templating or soft templating, preferably ionothermal carbons synthesis or advanced ionothermal carbons synthesis.

[0071] Activation of carbonaceous materials is typically performed by gas activation or chemical activation, preferably chemical activation. Gas activation can be performed using air, diluted oxygen, CO2, or steam, and chemical activation can be performed using H3PO4, KOH, NaOH, Na2CO3, K2CO3, ZnCl2, or other chemical activating agents.

[0072] The distinction between the two aforementioned embodiments with regard to the production of carbon-containing materials is not due to technical reasons, but is based on a division of the invention by the applicants.

[0073] The production of mesoporous carbonaceous materials is known in principle. If the mesoporous particles are carbon-based materials, they can be produced by chemical reactions within a substance or mixture of substances made at least partially from organic substances and at least partially liquid at least once during the synthesis. In particular, the carbonaceous mesoporous particles can be obtained within the scope of the present invention using the following processes:

[0074] By activating carbonized materials:

[0075] By activating lignin, especially kraft lignin. Kraft lignin is obtained, in particular, during cellulose production using the sulfate or kraft process. Activation can be carried out by gas activation with air, diluted oxygen, CO2, or steam, or preferably by chemical activation with H3PO4, KOH, NaOH, Na2CO3, K2CO3, ZnCl2, or other chemical activating agents, as described, for example, in Li, X. and Luo, X., "Preparation of mesoporous activated carbon from Kraft lignin by impregnation with H2SO4: A four-parameter optimization study," Environ. Prog. Sustainable Energy, 2013, 32: 1158-1163. https: / / d0i.0rg / l0.1002 / ep.11716.

[0076] By activating other carbonized carbonaceous materials, such as wood, straw, or car tires. Activation can also be carried out in this case by gas activation with air, diluted oxygen, CO2, or water vapor, or preferably by chemical activation with H3PO4, KOH, NaOH, Na2CO3, K2CO3, ZnCl2, or other chemical activating agents. An exemplary synthesis is described in Y. Lu et al., “Mesoporous activated carbon materials with ultrahigh mesopore volume and effective specific surface area for high-performance supercapacitors,” Carbon, Volume 124, 2017, pp. 64-71, ISSN 0008-6223, https: / / doi.org / 10.1016 / j.carbon.2017.08.044.

[0077] By a sol-gel process according to or similar to EP 2 475 272 B1 , wherein the drying step can be carried out in supercritical CO2 (aerogel), at normal pressure or a pressure below the critical pressure of CO2 (xerogel) or as freeze-drying (cryogel), with subsequent carbonization (pyrolysis).

[0078] From sugars or polyalcohols via a template process with low-melting salt mixtures, yielding ionothermal carbons or advanced ionothermal carbons. - By hard templating, for example with zeolites, mesoporous silicon dioxide, alumina, metals, metal oxides, MOFs, inorganic nanoparticles, or carbonaceous materials, in particular ordered mesoporous carbons, polymeric foams, carbon nanotubes (CNTs), and graphene oxide (GO), as described, for example, in Asasian-Kolur, N. et al., "Ordered porous carbon preparation by hard templating approach for hydrogen adsorption application," Biomass Conversion and Biorefinery 2023, Doi: 10.1007 / s13399-023-04282-x.

[0079] - By soft templating, for example with block copolymers such as Pluronic F127 (CAS number: 9003-11-6) or Pluronic P123, as described in Su, J. et al., "A controllable soft-templating approach to synthesize mesoporous carbon microspheres derived from d-xylose via hydrothermal method", Journal of Materials Science & Technology 2020, 183-188, Doi: 10.1016 / j.jmst.2O19.03.050.

[0080] EP 2 475 272 B1 describes the production of mesoporous carbonaceous particles based on resorcinol-formaldehyde resins by gelation, drying, carbonization, in particular by temperature treatment at up to approximately 1,000 °C without activating agent, and subsequent activation, in particular by gas activation with CO2 or H2O at up to approximately 1,000 °C.

[0081] Another process listed above for producing carbonaceous materials is called "ionothermal carbon synthesis." In this process, a carbohydrate or a similar substance, e.g., glucose, as a carbon source is mixed with a dry salt mixture, for example, NaCl or KCl and ZnCl2, which, on the one hand, forms a eutectic with the lowest possible melting point and, on the other hand, contains a chemical activating agent, such as ZnCl2 in this case. The mixture is slowly heated under an inert atmosphere to approximately 20 to 120 °C above the melting temperature of the salt mixture and held at this temperature. The salts melt and, at the same time, the carbon source decomposes, forming a coarse pore system. The mixture is then heated to a temperature significantly higher than that at which the activating agent begins to act as such. This temperature is maintained before the mixture is cooled to room temperature.The resulting substance is then ground or crushed and washed. This process is disclosed in particular in Jonas Pampel, Caleb Denton, and Tim-Patrick Fellinger, "Glucose-derived ionothermal carbons with tailor-made porosity," Carbon 107 (2016) 288-296, and Jonas Pampel and Tim-Patrick Fellinger, "Opening of Bottleneck Pores for the Improvement of Nitrogen-Doped Carbon Electrocatalysts," Adv. Energy Mater. 2016, 1502389, DOI: 10.1002 / aenm.201502389.

[0082] According to DE 10 2020 105 236 A1, the ionothermal carbons process described above can be carried out more easily on an industrial scale and with recovery of the salts by carrying out the various reaction steps in different reactors, preceded by a caramelization step of the mixture at the very beginning, and carried out the activation as gas activation with CO2 or H2O or omitted altogether, whereby the salt mixture can preferably be completely washed out and recycled after the coarse pore system has formed. This process is also referred to as the "advanced ionothermal carbons" process or synthesis. Furthermore, it is possible for the advanced ionothermal carbons to be post-carbonized after the salts have been washed out at a temperature that exceeds the highest temperature used in the manufacturing process.When the Advanced Ionothermal Carbons are post-carbonized, it is usually intended that the post-carbonization is carried out at temperatures of at least 600 °C, in particular at least 900 °C.

[0083] The ionothermal carbons and advanced ionothermal carbons typically still contain salts from the manufacturing process. Surprisingly, these salts do not adversely affect the material's suitability as a conductive additive for electrically conductive plastics. In particular, the ionothermal carbons and / or advanced ionothermal carbons can contain up to 5 atom% salt-forming ions, in particular up to 1 atom% salt-forming ions, preferably up to 0.1 atom% salt-forming ions, more preferably up to 0.01 atom% salt-forming ions, particularly preferably up to 0.001 atom% salt-forming ions, based on the amount of salts and ionothermal carbons or advanced ionothermal carbons. To determine the atom%, the salt-forming ions of the salts are counted as atoms, with complex anions or cations also being counted as one "atom."Thus, the compound NaCl consists, as expected, of two atoms, while the compound CaCO3 also consists of two atoms. Within the scope of the present invention, it is preferred if the carbonaceous material contains a proportion of sp. 2 -hybridized carbon of at least 40%, in particular at least 50%, preferably at least 90%, preferably at least 95%, based on the carbon of the carbon-containing material.

[0084] Due to the high proportion of sp 2 -hybridized carbon, the number of freely mobile electrons in the carbonaceous material is high, so that good electrical conductivity can be achieved overall. The proportion of sp 2 - hybridized carbon is determined by X-ray photoelectron spectroscopy (XPS) according to Morgan, DJ, "Comments on the XPS Analysis of Carbon Materials", Journal of Carbon Research 2021 , 7 (3), 51.

[0085] Likewise, within the scope of the present invention, it may be provided that the carbonaceous material contains a proportion of sp 2 -hybridized carbon in the range of 40 to 100%, in particular 45 to 99.9%, preferably 50 to 99.8%, preferably 90 to 99.5%, particularly preferably 95 to 99.5%, based on the carbon of the carbon-containing material.

[0086] Furthermore, within the scope of the present invention, it is preferably provided that the carbon-containing material has a carbon content of at least 45 atomic%, in particular at least 50 atomic%, preferably at least 60 atomic%, preferably at least 70 atomic%, preferably at least 90 atomic%, based on the carbon-containing material.

[0087] It can also be provided that the carbon-containing material has a carbon content in the range of 45 to 100 atomic%, in particular 50 to 99.9 atomic%, preferably 60 to 99.8 atomic%, preferably 70 to 99.5 atomic%, particularly preferably 90 to 99.5 atomic%, based on the carbon-containing material.

[0088] In the context of the present invention, atomic percent (atomic %) is understood to mean the percentage of atoms with selected properties relative to the total number of atoms in the sample under consideration.

[0089] As previously stated, the mesoporous particles can be electrically conductive core-shell structured mesoporous materials, for example, CNTs@TiO2 (CNT: Carbon Nanotubes). An exemplary synthesis is described in Yanhong Lu, Suling Zhang, Jiameng Yin, Congcong Bai, Junhao Zhang, Yingxue Li, Yang Yang, Zhen Ge, Miao Zhang, Lei Wei, Maixia Ma, Yanfeng Ma, Yongsheng Che, "Mesoporous activated carbon materials with ultrahigh mesopore volume and effective specific surface area for high-performance supercapacitors", Carbon, Volume 124, 2017, pp. 64-71, ISSN 0008-6223, https: / / doi.org / 10.1016 / j.carbon.2017.08.044.

[0090] As previously mentioned, the mesoporous particles can be electrically conductive covalent organic frameworks (COFs) or COF-derived carbons. Exemplary synthesis routes are described in X. Zhao, P. Pachfule, and A. Thomas, "Covalent organic frameworks (COFs) for electrochemical applications," Chemical Society Reviews, 12, 2021; https: / / pubs.rsc.org / en / content / articlelanding / 2021 / cs / d0cs01569e.

[0091] If the mesoporous material is a metal oxide, it has proven advantageous if the metal oxide is selected from the group consisting of tin(IV) oxide, manganese oxide, silver oxide, antimony oxide, cobalt(II,III) oxide, copper(II) oxide, lanthanum oxide, cerium(IV) oxide, aluminum oxide, titanium oxide, zirconium oxide, niobium oxide, and mixtures thereof. It is particularly preferred if the metal oxide is selected from the group consisting of tin(IV) oxide, manganese oxide, silver oxide, antimony oxide, cobalt(II,III) oxide, copper(II) oxide, lanthanum oxide, and mixtures thereof.

[0092] Furthermore, it can be provided within the scope of the invention that the mesoporous particles are selected from nitrides, carbides and mixtures thereof, preferably metal nitrides, metal carbides and mixtures thereof.

[0093] If the mesoporous particles are nitrides and / or carbides, it has proven advantageous if the mesoporous particles are selected from nitrides and carbides of elements from the group of B, Al, Ti, Ga, In, Ti, Si, Ge, Sn, Pb, P, As, S, Cd, V, Cr, Mn, W, Co, Ni, Zn, Zr and mixtures thereof.

[0094] Mesoporous materials based on non-intrinsically mesoporous oxides, carbides, or nitrides can be obtained, for example, according to Qi Lu, Cha-Jung Chen, Wesley Luc, Jingguang G. Chen, Aditya Bhan, and Feng Jiao, “Ordered Mesoporous Metal Carbides with Enhanced Anisole Hydrodeoxygenation Selectivity,” ACS Catal. 2016, 6, 6, 3506-3514 or Wesley Luc and Feng Jiao, “Synthesis of Nanoporous Metals, Oxides, Carbides, and Sulfides: Beyond Nanocasting”; Acc. Chem. Res. 2016, 49, 7, 1351-1358.

[0095] If the mesoporous particles comprise or consist of porous polymers, it has proven advantageous if the porous polymers are selected from the group consisting of polyacetylene, polyaniline, polyparaphenylene, polypyrrole, polythiophene, PEDOT:PSS, and mixtures thereof. Porous polymers can either be intrinsically porous polymers or obtained as mesoporous particles through special manufacturing processes, for example, templating. The production of mesoporous polymers is described, among others, in Srabanti Ghosh, Thandavarayan Maiyalagan, and Rajendra N. Basu, “Nanostructured conducting polymers for energy applications: towards a sustainable platform,” Nanoscale, 2016, 8, 6921–6947.

[0096] As previously stated, the mesoporous particles are porous. It has proven effective if the specific pore volume of the mesopores, i.e., the pores with a size of 2 to 50 nm, of the mesoporous particles, determined by nitrogen adsorption and evaluation according to the Barrett-Joyner-Halenda and / or t-plot method, is 0.01 to 5 cm 3 / g, especially 0.05 to 2.8 cm 3 / g, preferably 0.1 to 2.5 cm 3 / g, preferably 0.13 to 2.2 cm 3 / g, particularly preferably 0.15 to 2.0 cm 3 / g.

[0097] Similarly, the specific surface area of ​​the mesopores of the mesoporous particles, determined by nitrogen adsorption and evaluation according to the t-plot method, can be 10 to 1,000 m 2 / g, especially 10 to 500 m 2 / g, preferably 10 to 300 m 2 / g, preferably 15 to 200 m 2 / g, particularly preferably 20 to 150 m 2 / g.

[0098] Furthermore, it is preferably provided that the specific total surface area of ​​the mesoporous particles, determined according to Brunauer-Emmett-Teller (BET), is in the range of 10 to 3,000 m 2 / g, especially 20 to 2,500 m 2 / g, preferably 30 to 2,000 m 2 / g, preferably 40 to 2,000 m 2 / g, particularly preferably 50 to 1,800 m 2 / g, preferably 50 to 1,200 m 2 / g, particularly preferably 50 to 1,000 m 2 / g. The BET evaluation within the scope of this invention adheres to the Rouquerol criteria.

[0099] The volume-related proportion of mesopores in the mesoporous particles is preferably at least 22%, in particular at least 30%, preferably at least 35%, and more preferably at least 40%, based on the total pore volume of the mesoporous particles. The total pore volume is understood to be the sum of the micropores and mesopores of a material.

[0100] The density of the mesoporous particles can vary widely. However, it has proven to be advantageous if the mesoporous particles have an apparent density in the range of 0.0001 to 2 g / cm 3 , in particular 0.001 to 1.8 g / cm 3 , preferably 0.1 to 1.6 g / cm 3 , preferably 0.15 to 1.4 g / cm 3 , particularly preferably 0.2 to 1.2 g / cm 3 The density of mesoporous particles is expressed as apparent density. It comprises the quotient of the mass and the external particle volume, which consists of the solid and pore volume, as stated in "Activated Carbon and Its Industrial Application," ISBN 3-432-90881-4, 1980, page 56.

[0101] Furthermore, the mesoporous particles may contain foreign or heteroatoms, in particular, they may be doped. Heteroatoms are, in particular, atoms that do not correspond to carbon or hydrogen in organic molecules. Foreign atoms are, in particular, atoms that are not provided for in the chemical compound underlying the porous particles and either replace atoms from the structure of the chemical compound or structure or are additionally present, in particular, embedded in the solid-state structure.

[0102] Within the scope of the present invention, it can be provided in particular that the mesoporous particles comprise atoms, in particular heteroatoms or foreign atoms, selected from the group of nitrogen, oxygen, boron, phosphorus, sulfur, antimony, arsenic, indium, gallium, silicon and mixtures thereof.

[0103] Particularly good results are obtained within the scope of the present invention when the mesoporous particles comprise atoms, in particular heteroatoms or foreign atoms, selected from the group of nitrogen, oxygen, boron, phosphorus and mixtures thereof.

[0104] If the mesoporous particles contain foreign or heteroatoms, the proportion of these atoms is typically 0.000001 to 50 atomic%, in particular 0.000001 to 40 atomic%, preferably 0.000005 to 35 atomic%, more preferably 0.000005 to 15 atomic%, based on the mesoporous particles. The foreign or heteroatoms can be introduced into the mesoporous particles, in particular, as substitution or as doping.

[0105] If the foreign or heteroatoms are introduced into the mesoporous particles, particularly as substitutions, the proportion of these atoms is typically 0.01 to 50 atomic%, in particular 0.1 to 40 atomic%, preferably 1 to 35 atomic%, and more preferably 2 to 15 atomic%, based on the mesoporous particles. In the substitution, in particular, some of the atoms of the basic chemical substance from which the material of the mesoporous particles is derived are replaced by foreign or heteroatoms.

[0106] If the foreign atoms are introduced into the mesoporous particles as doping, it has proven advantageous if the mesoporous particles contain the foreign atoms in amounts of 0.000001 to 0.0005 atom-%, in particular 0.000001 to 0.0001 wt-%, preferably 0.000005 to 0.0001 wt-%, preferably 0.000005 to 0.00005 wt-%, based on the mesoporous particles.

[0107] Hetero- or foreign atoms can be introduced into the mesoporous particles in particular by the following methods:

[0108] - By adding substances containing these heteroatoms in the manufacturing process o e.g. for oxygen: e.g. ketones, aldehydes, alcohols, carboxylic acids, ethers, esters o e.g. for nitrogen: e.g. amines, amides, imines, amino acids,

[0109] Nitro compounds or azides o e.g. for phosphorus: phosphines, phosphates, phosphonates,

[0110] Phosphoramides.

[0111] - By impregnation, ie application to the surface of the solid, of the mesoporous particles or their already porous intermediates or starting materials with the heteroatom substances or with substances containing these heteroatoms, and optional post-treatment, eg evaporation of solvents in which the heteroatoms are dissolved, or decomposition of the substances containing the heteroatoms.

[0112] - By post-synthetic treatment of mesoporous particles, in particular carbon materials, whereby the modification of the carbon framework takes place within the solid, for example by o treatment with hydrogen peroxide or potassium permanganate to introduce oxygen, o treatment with ammonia or nitric acid to introduce nitrogen.

[0113] - By high-temperature treatment from approx. 500 °C or plasma treatment with CO2, H2O, O2, NH3, N2.

[0114] As far as the particle size of the mesoporous particles is concerned, this can vary widely.

[0115] However, it has proven advantageous for the mesoporous particles to have a particle size distribution D90 in the range of 1 to 300 pm, in particular 1 to 200 pm, preferably 1 to 150 pm. In the context of this invention, the particle size distributions are determined in particular by means of static laser scattering (SLS).

[0116] However, within the scope of the present invention, it can also be provided that the mesoporous particles have a particle size distribution D90 in the range from 0.1 to 50 pm, in particular 0.2 to 20 pm, preferably 0.5 to 10 pm.

[0117] Which of the aforementioned particle sizes is used depends in particular on whether, for example, graphite or carbon black is replaced by the mesoporous particles in conventional bipolar plates containing conductive carbon black and graphite. If graphite is replaced, the larger aforementioned particles are preferably used, whereas if carbon black is replaced, the smaller particle sizes are used.

[0118] In practice, often starting from a recipe for bipolar plate material containing carbon black and graphite, one or both of these components is replaced completely or partially by mesoporous particles, in particular mesoporous carbons, and for this purpose the mesoporous particles, in particular the mesoporous carbon, are optimized according to pore structure, specific surface area or specific volume, in particular of the mesopores, particle size distribution and chemical composition, for example ashes or desired foreign atoms.

[0119] According to a preferred embodiment of the present invention, it is provided that the mesoporous particles have a multimodal, in particular biomodal, particle size distribution.

[0120] A multimodal, particularly bimodal, particle size distribution ensures that the electrically conductive plastic is filled as highly as possible with electrically conductive particles, particularly electrically conductive mesoporous particles. The use of particles with a multimodal, or particularly bimodal, particle size distribution ensures that the smaller particles are embedded in the spaces between the larger particles, i.e., in the gaps in the sphere packing, thereby reducing the distances between the individual particles and increasing contact between the particles. This increases the electrical conductivity of the electrically conductive plastic. Different mesoporous particles with different particle sizes can also be used.

[0121] If the mesoporous particles have a biomodal particle size distribution, it is preferred if the bimodal particle size distribution has a first maximum in the range from 1 to 300 pm, in particular 1 to 200 pm, preferably 1 to 150 pm, and a second maximum in the range from 0.1 to 50 pm, in particular 0.2 to 20 pm, preferably 0.5 to 10 pm.

[0122] The electrically conductive plastic generally contains at least one polymer.

[0123] As far as the polymer of the electrically conductive plastic is concerned, this can be selected from a variety of possible polymers.

[0124] Typically, however, the polymer of the electrically conductive plastic is selected from the group of thermoplastic polymers, thermosetting polymers, natural polymers, and mixtures thereof, in particular thermoplastic polymers, thermosetting polymers, and mixtures thereof, preferably thermoplastic polymers. Particularly good results are obtained in this context when the polymer is selected from thermoplastic polymers, thermosetting polymers, and mixtures thereof.

[0125] Particularly good results are obtained in the context of the present invention when the polymer is a thermoplastic polymer.

[0126] Typically, the polymer of the electrically conductive plastic is selected from the group of polyolefins, in particular polyethylene (PE), polypropylene (PP), polyetheretherketone (PEEK), polyphenylene sulfide (PPS), polyaryletherketone (PAEK), polyetherketoneketone (PEKK), polyetherimides (PEI), acrylonitrile-butadiene-styrene (ABS), polyamides (PA), polyphenylsulfones (PPS), polysulfone (PS), polyethersulfone (PES), polyamide-imides (PAI), polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polyvinyl alcohol (PVA), cellulose derivatives, in particular cellulose esters, cellulose ethers, preferably carboxymethylcellulose, resorcinol-formaldehyde resins, phenol-formaldehyde resins, urea-formaldehyde resins, melamine resins, in particular melamine-formaldehyde resins, melamine-urea-formaldehyde resins, Melamine-phenol-formaldehyde resins and their mixtures, in particular polyethylene (PE), polypropylene (PP), polyetheretherketone (PEEK), polyphenylene sulfide (PPS), polyaryletherketone (PAEK),Polyether ketone ketone (PEKK), polyetherimides (PEI), acrylonitrile butadiene styrene (ABS), polyamides (PA), polyphenylsulfones (PPS), polysulfone (PS), polyethersulfone (PES), polyamide-imides (PAI), polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polyvinyl alcohol (PVA) and their mixtures, preferably polyethylene (PE), polypropylene (PP), polyetheretherketone (PEEK), polyphenylene sulfide (PPS) and their mixtures.

[0127] Furthermore, it has proven useful in the context of the present invention if the electrically conductive plastic contains the polymer in amounts of 1 to 99.5 wt.%, in particular 2 to 99 wt.%, preferably 10 to 95 wt.%, based on the plastic.

[0128] In the context of the present invention, it is preferred if the electrically conductive plastic contains the polymer in amounts of 20 to 75 wt.%, in particular 25 to 70 wt.%, preferably 30 to 60 wt.%, based on the plastic. This embodiment is preferred if conductive plastics are to be obtained which contain only the mesoporous particles as conductive particles.

[0129] Within the scope of the present invention, it is further preferred if the electrically conductive plastic contains the polymer in amounts of 10 to 35 wt.%, in particular 12 to 30 wt.%, preferably 15 to 25 wt.%, based on the plastic. This embodiment is preferred if conductive structures are to be obtained which contain further conductive particles in addition to the mesoporous particles.

[0130] In general, it is intended that the plastic contains the mesoporous particles in amounts of 0.5 to 90 wt.%, in particular 5 to 80 wt.%, preferably 10 to 75 wt.%, more preferably 10 to 75 wt.%, particularly preferably 15 to 70 wt.%, based on the plastic.

[0131] Furthermore, it can be provided that the plastic contains the mesoporous particles in amounts of 10 to 90 wt.%, in particular 30 to 80 wt.%, preferably 40 to 70 wt.%, based on the electrically conductive plastic. This embodiment is particularly preferred if the electrically conductive plastic contains only the mesoporous particles as conductive particles.

[0132] According to a further embodiment, the plastic contains the mesoporous particles in amounts of 0.5 to 40 wt.%, in particular 1 to 30 wt.%, preferably 5 to 25 wt.%, based on the electrically conductive plastic. This embodiment is particularly preferred if the electrically conductive plastic contains further conductive particles.

[0133] Furthermore, within the scope of the present invention, it may be provided that the plastic contains further electrically conductive particles.

[0134] In particular, it can be provided in this context that the further electrically conductive particles are carbon-based particles. The carbon-based particles are, in particular, particles selected from the group of carbides, MAX phases, MXenes, (conductive) carbon black, graphite, graphene, carbon nanotubes, onion-like carbons, and mixtures thereof. According to a particularly preferred embodiment of the present invention, the further electrically conductive particles are carbon-based particles and are preferably selected from the group of (conductive) carbon black, graphite, and mixtures thereof, in particular (conductive) carbon black or graphite.

[0135] If the other conductive particles are carbides, it has proven to be advantageous if the conductive particles are selected from carbides of elements from the group of B, Al, Ti, Ga, In, Ti, Si, Ge, Sn, Pb, P, As, S, Cd, V, Cr, Mn, W, Co, Ni, Zn, Zr and mixtures thereof.

[0136] Furthermore, it can be provided that the further conductive particles contain or consist of MAX phases or MXenes, preferably MXenes. In the context of the present invention, MAX phases are particularly carbides and nitrides of the general formula M crystallizing in hexagonal layers. n +iAXn with n = 1 to 3. M stands for an early transition metal from groups 3 to 6 of the periodic table of elements, while A stands for an element from groups 13 to 16 of the periodic table. A is in particular selected from Cd, Al, Ga, In, Ti, Si, Ge, Sn, Pb, P, As, S and mixtures thereof, while M is preferably selected from Sc, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo and mixtures thereof. Finally, X is either carbon or nitrogen.

[0137] MAX phases often exhibit unusual combinations of chemical, physical, electrical, and mechanical properties, exhibiting both metallic and ceramic behavior depending on the conditions. This includes, for example, high electrical and thermal conductivity, high thermal shock resistance, very high hardness, and low thermal expansion coefficients.

[0138] MAX phases are highly resistant to chemicals and to oxidation at high temperatures.

[0139] MXenes are two-dimensional structures based on metal carbides and / or metal nitrides and can be obtained in particular by etching MAX phases, for example, with HF. Within the scope of the present invention, it is preferably provided that the mesoporous particles replace some of the commonly used graphite or carbon black particles, in particular completely.

[0140] Furthermore, it can be provided that the plastic contains the further electrically conductive particles in amounts of 1 to 90 wt.%, in particular 30 to 85 wt.%, preferably 50 to 80 wt.%, based on the plastic.

[0141] If the electrically conductive plastic contains additional conductive particles, it has proven advantageous if the mesoporous particles and the additional conductive particles have a multimodal, in particular biomodal, particle size distribution.

[0142] In this context, it is preferred if the bimodal particle size distribution has a first maximum in the range from 1 to 300 pm, in particular 1 to 200 pm, preferably 1 to 150 pm, and a second maximum in the range from 0.1 to 50 pm, in particular 0.2 to 20 pm, preferably 0.5 to 10 pm, based on a mixture of the mesoporous particles and the further conductive particles.

[0143] A further subject matter of the present invention - according to a second aspect of the present invention - is the use of an aforementioned electrically conductive plastic for the production of bipolar plates, in particular for electrochemical reactors, preferably storage devices and converters, in particular in the field of fuel cell and battery technology.

[0144] The electrically conductive plastic according to the invention can be used in particular for the production of bipolar plates.

[0145] The electrically conductive plastic is preferably used in bipolar plates for PEM fuel cells, redox flow batteries or for capacitive deionization (CDI), in particular flow electrode capacitive deionization (FCDI).

[0146] The electrically conductive plastic preferably contains the polymer in amounts of 5 to 99.5 wt.%, in particular 20 to 75 wt.%, preferably 25 to 70 wt.%, preferably 30 to 60 wt.%, based on the plastic, if the electrically conductive plastic contains only the mesoporous particles as conductive particles. Furthermore, according to this embodiment, it is preferably provided that the plastic contains the porous particles in amounts of 15 to 90 wt.%, in particular 30 to 80 wt.%, preferably 40 to 70 wt.%, based on the plastic.

[0147] If the electrically conductive plastic contains further conductive particles, in particular graphite, the electrically conductive plastic usually contains the polymer in amounts of 10 to 35 wt.%, in particular 12 to 30 wt.%, preferably 15 to 25 wt.%, based on the plastic.

[0148] Furthermore, according to this embodiment, it is preferably provided that the plastic contains the porous particles in amounts of 0.5 to 40 wt.%, in particular 1 to 30 wt.%, preferably 5 to 25 wt.%, based on the plastic.

[0149] Furthermore, according to this embodiment, it is preferably provided that the plastic contains the further electrically conductive particles in amounts of 1 to 90% by weight, in particular 30 to 85% by weight, preferably 50 to 80% by weight, based on the plastic.

[0150] For further details on this aspect of the invention, reference can be made to the above statements on the electrically conductive plastic according to the invention, which apply accordingly with regard to the use according to the invention.

[0151] Yet another object of the present invention - according to a third aspect of the present invention - is the use of an aforementioned electrically conductive plastic for producing an intermediate product, in particular a filament and / or a granulate.

[0152] The intermediate product can be used to produce objects consisting of or containing the plastic according to the invention. The filament can be used in particular to produce objects using 3D printing processes, preferably using fused deposition modeling (FDM) or fused filament fabrication (FFF), whereas the granulate can be used for extrusion or powder bed processes, such as selective laser sintering (SLS). For further details on this aspect of the invention, reference can be made to the preceding statements on the other aspects of the invention, which apply accordingly with regard to the use according to the invention.

[0153] A further subject matter of the present invention - according to a fourth aspect of the present invention - is the use of an aforementioned electrically conductive plastic for the production of electrically conductive films, packaging, layers and coatings.

[0154] The films and layers can be used either for the production of bipolar plates in battery stacks or as electrically conductive and antistatic coatings. The production of antistatic packaging, particularly for electronic components, is also possible.

[0155] For further details on this aspect of the invention, reference can be made to the preceding statements on the other aspects of the invention, which apply accordingly with regard to the use according to the invention.

[0156] Yet another object of the present invention - according to a fifth aspect of the present invention - is the use of an aforementioned electrically conductive plastic as a catalyst.

[0157] For further details on this aspect of the invention, reference can be made to the preceding statements on the other aspects of the invention, which apply accordingly with regard to the use according to the invention.

[0158] Yet another object of the present invention - according to a sixth aspect of the present invention - is the use of an aforementioned electrically conductive plastic as a heating element.

[0159] For further details regarding this aspect of the invention, reference can be made to the preceding statements regarding the other aspects of the invention, which apply accordingly with regard to the use according to the invention. A further subject of the present invention—according to a seventh aspect of the present invention—is a process for producing an aforementioned electrically conductive plastic, wherein the polymer and the mesoporous particles, as well as optionally other particles, are processed into a plastic, in particular by compounding.

[0160] Compounding typically takes place in an extruder, with extrusion followed by either granulation using hot or cold die cutting or the extruded plastic being directly processed, for example, into fibers, films, or molded articles. It is also possible to mix the polymer hot and then process the mass. Alternatively, compounding and direct further processing of the compound can also be carried out using the powder-to-roll process according to WO 2015 / 007544 A1.

[0161] For further details on the method according to the invention, reference can be made to the above statements on the other aspects of the invention, which apply accordingly with regard to the method according to the invention.

[0162] Yet another subject matter of the present invention - according to an eighth aspect of the present invention - is a bipolar plate containing or consisting, preferably consisting, of an aforementioned plastic.

[0163] For further details on this aspect of the invention, reference can be made to the statements on the other aspects of the invention, which apply accordingly with regard to the bipolar plate according to the invention.

[0164] Yet another subject matter of the present invention - according to a ninth aspect of the present invention - is a film containing or consisting, preferably consisting, of an aforementioned plastic.

[0165] For further details regarding this aspect of the invention, reference can be made to the statements regarding the other aspects of the invention, which apply accordingly with regard to the film according to the invention. Yet another subject of the present invention—according to a tenth aspect of the present invention—is an intermediate product, in particular a filament and / or a granulate, containing or consisting, preferably consisting, of an aforementioned plastic.

[0166] For further details on this aspect of the invention, reference can be made to the statements on the other aspects of the invention, which apply accordingly with regard to the fiber according to the invention.

[0167] Yet another subject matter of the present invention - according to an eleventh aspect of the present invention - is a shaped body containing or consisting, preferably consisting, of an aforementioned plastic.

[0168] The molded body can in particular be a packaging or a heating element.

[0169] For further details on this aspect of the invention, reference can be made to the statements on the other aspects of the invention, which apply accordingly with regard to the shaped body according to the invention.

[0170] Yet another subject matter of the present invention - according to a twelfth aspect of the present invention - is a method for producing a bipolar plate, wherein an aforementioned electrically conductive plastic is formed, in particular rolled, into a plate.

[0171] For further details on this aspect of the invention, reference can be made to the statements on the other aspects of the invention, which apply accordingly with regard to the shaped body according to the invention.

[0172] The subject matter of the present invention is illustrated below in a non-limiting manner by way of example by the embodiments: Embodiments

[0173] 1. Production of mesoporous carbon particles using sol-gel synthesis

[0174] 1.1. Production of brines

[0175] The brine is produced using the following process:

[0176] First, resorcinol is dissolved in water, then sodium carbonate is added as a catalyst, and finally formaldehyde (stabilized in 37 wt% methanol) is added. The sol is stirred for 10 minutes and then transferred to a reactor for the subsequent synthesis steps. The molar ratios of the reactants and the solids content for this synthesis route are given in Table 1.

[0177] Table 1 : Starting materials and molar ratios

[0178] 1 R: Resorcinol

[0179] 2 F: Formaldehyd

[0180] 3 C: Sodium carbonate

[0181] 1.2 Gelation and carbonization

[0182] The sols obtained under 1.1 are gelled, dried and carbonized according to the following procedures:

[0183] Gelation method

[0184] The sol is heated to 50 °C in a closed reactor (V2A steel with enamel lining) and held for 2 hours. The temperature is then increased to 70 °C and held for another 2 hours. Finally, the temperature is increased to 90 °C and maintained for 16 hours. After gelation is complete, the reactor is cooled to room temperature under ambient conditions.

[0185] Drying method

[0186] The hydrogel is removed from the reactor, crushed into large pieces, and placed in a sieve. The sieve is heated to 90 °C in a closed drying cabinet with a constant flow of compressed air, and the hydrogel is dried for 48 hours. Compressed air is introduced at a flow rate of approximately 2,000 L / h.

[0187] Carbonization method

[0188] After drying, the xerogel is ground in a drum grinder and then carbonized in a rotary kiln. The xerogel is heated to 1,000 °C under 90 L / h of nitrogen at a rate of 10 K / min and held for 2 hours. The carbon xerogel is then cooled to ambient temperature under a constant nitrogen flow.

[0189] 1 .3 Further procedures

[0190] In addition to the methods described above, other methods have been used to produce mesoporous carbonaceous particles.

[0191] 1.3.1 Superfast method (SF)

[0192] The Superfast method is a synthesis method that involves gelation and direct carbonization of the hydrogel and is described in Bilican, Abdurrahman; Sharma, Priyanka; Nguyen, Khang Tran; Weidenthaler, Claudia; and Schmidt, Wolfgang: Superfast Synthesis of Carbon Xerogels. ACS Omega 2023 8 (48), 45599–45605, DOI: 10.1021 / acsomega.3c05824. 1.3.2 According to EP 2 475 272 B1 (Pat)

[0193] Manufactured according to the method described in EP 2 475 272 B1 "Smoke Filtration".

[0194] The xerogels obtained under 1.1 to 1.3 and their properties are listed in Table 2. In addition to the respective preparation processes, Table 2 also lists the pore volumes (total pore volume as well as volumes of mesopores and macropores) and the BET surface areas (total surface areas, surface areas of mesopores and surface areas of micropores) of the mesoporous materials.

[0195] Table 2: Preparation and properties of mesoporous

[0196] Carbon xerogels

[0197] 1 : Gelation, drying and carbonization method used

[0198] 2. Production of bipolar plates

[0199] Bipolar plates (BPP) are manufactured in the following way:

[0200] The polymer compound is dry mixed and transferred to a heated multi-roll mill, where the BPP is produced according to the process of WO 2015 / 007544 A1. From the resulting BPP, test specimens with a plate-shaped geometry of 1.2 cm 2The plates were manufactured with a surface area of ​​0.5 mm and a thickness of 0.5 mm and tested for their through-plane resistance at a contact pressure of 1 to 5 bar. PP with particle sizes of 100 to 150 pm was always used as the thermoplastic; synthetic graphite with a D9045-150 pm was used as the graphite; and carbon xerogels with the properties listed in Table 6 were used. Table 3: Examples of embodiments: Production and properties of the bipolar plates according to the invention

[0201] In addition to manufacturing according to WO 2015 / 007544 A1, bipolar plates can also be manufactured by extrusion followed by injection molding. Furthermore, the materials can be embedded in a thermosetting matrix, which is then formed into bipolar plates, particularly by hot pressing.

Claims

Patent claims:

1. Electrically conductive plastic, in particular electrically conductive polymer compound, characterized in that the plastic, in particular the polymer compound, contains mesoporous electrically conductive particles.

2. Electrically conductive plastic according to claim 1, characterized in that the mesoporous particles are selected from the group of carbon-containing materials, metal-organic frameworks (metal-organic frameworks (MOFs)), covalent organic frameworks (COFs), core-shell structured mesoporous materials, metal oxides, nitrides, carbides, porous polymers and mixtures thereof.

3. Electrically conductive plastic according to claim 2, characterized in that the carbon-containing material is a carbon gel and / or an activated carbon.

4. Electrically conductive plastic according to claim 2 or 3, characterized in that the carbon-containing material is obtainable by activation of carbonized materials, gel synthesis, in particular sol-gel synthesis, ionothermal carbons synthesis, advanced ionothermal carbons synthesis, hard templating or soft templating.

5. Electrically conductive plastic according to one of claims 2 to 4, characterized in that the carbon-containing material contains a proportion of sp 2 - hybridized carbon of at least 40%, in particular at least 50%, preferably at least 90%, preferably at least 95%, based on the carbon of the carbon-containing material.

6. Electrically conductive plastic according to one of claims 2 to 5, characterized in that the carbon-containing material has a carbon content of at least 45 atomic%, in particular at least 50 atomic%, preferably at least 60 atomic%, more preferably at least 70 atomic%, based on the carbon-containing material.

7. Electrically conductive plastic according to one of claims 2 to 6, characterized in that the carbon-containing material has a carbon content in the range from 45 to 100 atomic%, in particular 50 to 99.9 atomic%, preferably 60 to 99.8 atomic%, more preferably 70 to 99.5 atomic%, particularly preferably 90 to 99.5 atomic%, based on the carbon-containing material.

8. Electrically conductive plastic according to one of the preceding claims, characterized in that the metal oxide is selected from the group of tin(IV) oxide, manganese oxide, silver oxide, antimony oxide, cobalt(II,III) oxide, copper(II) oxide, lanthanum oxide, cerium(IV) oxide, aluminum oxide, titanium oxide, zirconium oxide, niobium oxide and mixtures thereof, in particular is selected from the group of tin(IV) oxide, manganese oxide, silver oxide, antimony oxide, cobalt(II,III) oxide, copper(II) oxide, lanthanum oxide and mixtures thereof.

9. Electrically conductive plastic according to one of the preceding claims, characterized in that the porous polymers are selected from the group of polyacetylene, polyaniline, polyparaphenylene, polypyrrole, polythiophene, PEDOT:PSS and mixtures thereof.

10. Electrically conductive plastic according to one of the preceding claims, characterized in that the specific pore volume of the mesopores of the mesoporous particles, determined by means of nitrogen adsorption and evaluation according to the Barrett-Joyner-Halenda and / or t-plot method, is 0.01 to 5 cm 3 / g, especially 0.05 to 2.8 cm 3 / g, preferably 0.1 to 2.5 cm 3 / g, preferably 0.13 to 2.2 cm 3 / g, particularly preferably 0.15 to 2.0 cm 3 / g.

11. Electrically conductive plastic according to one of the preceding claims, characterized in that the specific surface area of ​​the mesopores of the mesoporous particles, determined by means of nitrogen adsorption and evaluation according to the t-plot method, is 10 to 1,000 m 2 / g, especially 10 to 500 m 2 / g, preferably 10 to 300 m 2 / g, preferably 15 to 200 m 2 / g, particularly preferably 20 to 150 m 2 / g.

12. Electrically conductive plastic according to one of the preceding claims, characterized in that the specific total surface area of ​​the mesoporous particles, determined according to Brunauer-Emmett-Teller, is in the range from 10 to 3,000 m 2 / g, especially 20 to 2,500 m 2 / g, preferably 30 to 2,000 m 2 / g, preferably 40 to 2,000 m 2 / g, particularly preferably 50 to 1,800 m 2 / g, most preferably 50 to 1,200 m 2 / g, particularly preferably 50 to 1,000 m 2 / g.

13. Electrically conductive plastic according to one of the preceding claims, characterized in that the mesoporous particles comprise atoms, in particular heteroatoms or foreign atoms, selected from the group consisting of nitrogen, oxygen, boron, phosphorus, sulfur, antimony, arsenic, indium, gallium, silicon and mixtures thereof, in particular selected from the group consisting of nitrogen, oxygen, boron, phosphorus and mixtures thereof.

14. Electrically conductive plastic according to claim 14, characterized in that the proportion of atoms is 0.000001 to 50 atom-%, in particular 0.000001 to 40 atom-%, preferably 0.000005 to 35 atom-%, more preferably 0.000005 to 15 atom-%, based on the mesoporous particles.

15. Electrically conductive plastic according to one of the preceding claims, characterized in that the mesoporous particles have a particle size distribution D90 in the range from 1 to 300 pm, in particular 1 to 200 pm, preferably 1 to 150 pm.

16. Electrically conductive plastic according to one of claims 1 to 14, characterized in that the mesoporous particles have a particle size distribution D90 in the range from 0.1 to 50 pm, in particular 0.2 to 20 pm, preferably 0.5 to 10 pm.

17. Electrically conductive plastic according to one of the preceding claims, characterized in that the mesoporous particles have a multimodal, in particular bimodal, particle size distribution.

18. Electrically conductive plastic according to one of the preceding claims, characterized in that the electrically conductive plastic comprises at least one polymer, in particular wherein the polymer of the electrically conductive plastic is selected from the group of thermoplastic polymers, thermosetting polymers, natural polymers and mixtures thereof, in particular thermoplastic polymers, thermosetting polymers and mixtures thereof, preferably thermoplastic polymers.

19. Electrically conductive plastic according to claim 18, characterized in that the polymer of the electrically conductive plastic is selected from the group of polyolefins, in particular polyethylene (PE), polypropylene (PP), polyetheretherketone (PEEK), polyphenylene sulfide (PPS), polyaryletherketone (PAEK), polyetherketoneketone (PEKK), polyetherimides (PEI), acrylonitrile-butadiene-styrene (ABS), polyamides (PA), polyphenylsulfones (PPS), polysulfone (PS), polyethersulfone (PES), polyamide-imides (PAI), polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polyvinyl alcohol (PVA), cellulose derivatives, resorcinol-formaldehyde resins, phenol-formaldehyde resins, urea-formaldehyde resins, melamine resins, in particular melamine-formaldehyde resins, melamine-urea-formaldehyde resins, Melamine-phenol-formaldehyde resins and their mixtures, in particular polyethylene (PE), polypropylene (PP), polyetheretherketone (PEEK), polyphenylene sulfide (PPS), polyaryletherketone (PAEK),Polyether ketone ketone (PEKK), polyetherimides (PEI), acrylonitrile butadiene styrene (ABS), polyamides (PA), polyphenylsulfones (PPS), polysulfone (PS), polyethersulfone (PES), polyamide-imides (PAI), polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polyvinyl alcohol (PVA) and their mixtures, preferably polyethylene (PE), polypropylene (PP), polyetheretherketone (PEEK), polyphenylene sulfide (PPS) and their mixtures.

20. Electrically conductive plastic according to claim 18 or 19, characterized in that the plastic contains the polymer in amounts of 1 to 99.5% by weight, in particular 2 to 99% by weight, preferably 10 to 95% by weight, based on the plastic.

21. Electrically conductive plastic according to one of the preceding claims, characterized in that the plastic contains the mesoporous particles in amounts of 0.5 to 90 wt.%, in particular 5 to 80 wt.%, preferably 5 to 75 wt.%, preferably 10 to 75 wt.%, particularly preferably 15 to 70 wt.%, based on the plastic.

22. Electrically conductive plastic according to one of the preceding claims, characterized in that the plastic contains further electrically conductive particles.

23. Electrically conductive plastic according to claim 22, characterized in that the further electrically conductive particles are carbon-based particles, in particular wherein the carbon-based particles are selected from the group of carbides, MAX phases, MXenes, soot, graphite, graphene, carbon nanotubes, onion-like carbon and mixtures thereof, preferably soot, graphite and mixtures thereof.

24. Electrically conductive plastic according to claim 22 or 23, characterized in that the plastic contains further electrically conductive particles in amounts of 1 to 90 wt.%, in particular 1 to 60 wt.%, preferably 1 to 10 wt.%, based on the plastic.

25. Use of an electrically conductive plastic according to one of claims 1 to 24 for the production of bipolar plates, in particular for electrochemical reactors, preferably storage devices and converters, in particular in the field of fuel cell and battery technology.

26. Use of an electrically conductive plastic according to one of claims 1 to 24 for producing an intermediate product, in particular a filament and / or a granulate.

27. Use of an electrically conductive plastic according to one of claims 1 to 24 for the production of electrically conductive films, packaging, layers and coatings.

28. Use of an electrically conductive plastic according to one of claims 1 to 24 as a catalyst.

29. Use of an electrically conductive plastic according to one of claims 1 to 24 as a heating element.

30. A process for producing an electrically conductive plastic according to one of claims 1 to 24, characterized in that the polymer and the mesoporous particles and optionally further additives are processed to form a plastic, in particular by compounding.

31. Bipolar plate containing or consisting of a plastic according to one of claims 1 to 24.

32. A film containing or consisting of a plastic according to any one of claims 1 to 24.

33. Intermediate product, in particular filament and / or granulate, containing or consisting of a plastic according to one of claims 1 to 24.

34. Shaped body containing or consisting of a plastic according to one of claims 1 to 24.

35. Method for producing a bipolar plate, characterized in that an electrically conductive plastic according to one of claims 1 to 24 is shaped, in particular rolled, into a plate.

Images