Boron-doped carbon material, conductive composition, conductive film, and capacitive device

Abstract

The objective of the present invention is to provide a carbon material with excellent conductivity. The carbon material according to the present invention is a carbon material having a carbon hexagonal lattice as a basic framework and doped with boron elements to substitute carbon elements, wherein the content of boron elements in the carbon material is 0.005 to 15 mol%, and when the content of boron elements doped to substitute carbon elements on the surface of the carbon material is X (mol%) and the content of boron elements in the carbon material is Y (mol%), X / Y < 0.8.

Description

Technology Field

[0001] The present invention relates to a boron-doped carbon material, a conductive composition, a conductive film, and a capacitive device. Background Technology

[0002] Recently, with the remarkable advancement of electronics, there is a growing demand for conductive materials used in various electronic devices to be smaller, lighter, and more cost-effective, as well as to ensure long lifespans under various usage environments. For example, when manufacturing base wiring for electronic devices or wiring that connects electronic devices, a conductive composition with good conductivity is required. However, conductive compositions using metal fillers such as silver or copper are common, and a significant cost challenge remains unresolved. On the other hand, various studies have been conducted on conductive compositions using non-metallic conductive carbon, but due to insufficient conductivity, their use has been limited to semi-conductive applications such as antistatic applications.

[0003] In addition, regarding conductive carbon materials, conductive materials with low volume resistivity, such as various graphites and carbon nanotubes, have been investigated so far, but volume resistivity 10 -4 Compared to metal fillers that exhibit very high conductivity of less than Ω·cm, the volume resistivity is significantly higher, and improving conductivity was a major challenge.

[0004] Therefore, Patent Documents 1 and 2 report research on doping carbon nanotubes with boron by high-temperature heat treatment of carbon nanotubes and boron compounds for the purpose of improving electrical properties. By adding 3 mass% or more of a boron compound to multiwall carbon nanotubes and performing high-temperature heat treatment at up to 3000°C, the volume resistivity 10 -2Although conductivity at the Ω·cm level has been achieved, further improvement in conductivity is still needed. Additionally, regarding carbon nanotubes, the analysis of how boron is doped is insufficient, and the relationship between the boron doping state and conductivity has not been clearly established, which has been a challenge. Meanwhile, there have been reports that in carbon nanotubes with a diameter of 10 nm or less, boron doping through high-temperature heat treatment of 1600°C or higher makes it difficult to maintain the shape of the carbon nanotubes, and in single-walled or double-walled carbon nanotubes, they decompose, further complicating the relationship between the boron doping state and conductivity of boron-doped carbon materials.

[0005] In addition, Patent Document 3 reports a study on doping boron into graphene nanoplatelets with a very thin thickness of 100 nm or less by adding about 3 mass% of a boron source. In this report, the volume resistivity 10 -3 Excellent conductivity of less than Ω·cm was obtained, but compared to metal fillers, further improvement in conductivity is still needed. In addition, while the boron content in boron-doped carbon materials has been disclosed, it is not clear how the boron is doped into the carbon material.

[0006] Therefore, it is believed that the conductivity of boron-doped carbon materials can be further improved by analyzing the boron doping state of the boron in the boron-doped carbon materials and clarifying the relationship between the doping state and conductivity. Prior art literature

[0007] Japanese Patent Publication No. 2000-281323, Japanese Patent Publication No. 2009-256118, International Publication No. 2014 / 185496 The problem to be solved

[0008] The objective of the present invention is to provide a carbon material with excellent conductivity. means of solving the problem

[0009] The present invention relates to a carbon material having a carbon hexagonal mesh as a basic framework and doped with boron elements to substitute carbon elements, wherein the content of boron elements in the carbon material is 0.005 to 15 mol%, and when the content of boron elements doped to substitute carbon elements on the surface of the carbon material is X (mol%) and the content of boron elements in the carbon material is Y (mol%), X / Y < 0.8.

[0010] In addition, the present invention relates to a carbon material comprising at least one selected from the group consisting of graphite, graphene nanoplatelets, graphene, and carbon nanotubes.

[0011] In addition, the present invention comprises 0.01 <X / Y<0.4인 상기 탄소 재료에 관한 것이다.

[0012] In addition, the present invention relates to a conductive composition comprising the carbon material described above and at least one of a binder resin or a solvent.

[0013] In addition, the present invention relates to a conductive composition comprising two or more carbon materials that are different from each other.

[0014] In addition, the present invention relates to a conductive composition further comprising a conductive aid.

[0015] In addition, the present invention relates to a conductive composition that further comprises an active material and is used as a composite ink for forming a positive electrode or a negative electrode for a capacitor device.

[0016] In addition, the present invention relates to a conductive film formed from the conductive composition described above.

[0017] In addition, the present invention relates to a capacitor device having an electrode having a composite layer formed from the conductive composition described above. Effects of the invention

[0018] According to the present invention, a carbon material containing a boron element, having a carbon hexagonal mesh plane containing a boron element as a basic framework and doped to substitute carbon elements on the surface, can be provided with a carbon material having excellent conductivity by having a specific boron content. Brief explanation of the drawing

[0019] Figure 1 is a diagram showing an example of the peak and peak separation of the B1s spectrum in XPS, and Figure 2 is a diagram showing the peaks of the G band and D band of a carbon material in a laser Raman spectrum. Specific details for implementing the invention

[0020] The present invention will be described in detail below. In addition, in this specification, "a carbon material having a carbon hexagonal lattice as a basic framework and doped with boron elements to substitute carbon elements" may simply be referred to as "boron-doped carbon material."

[0021] Boron-doped carbon materials

[0022] The boron-doped carbon material of the present invention will be described. A boron-doped carbon material is a carbon hexagonal lattice having a basic framework of carbon atoms covalently bonded to form a hexagonal lattice, having physical and chemical interactions (bonding) between the constituent units, and containing boron elements, and is a carbon material containing at least boron elements doped to substitute carbon elements. Furthermore, "boron elements doped to substitute carbon elements" refers to boron elements substituted for carbon elements within the carbon hexagonal lattice, boron elements substituted for carbon elements at the edges of the carbon hexagonal lattice on the surface of the carbon material, boron elements bonded to carbon elements such as defects or missing parts existing as vacancies within the carbon hexagonal lattice on the surface of the carbon material, and boron elements bonded to carbon elements to connect the inter-planes of the carbon hexagonal lattice near the surface of the carbon material, and these boron elements can be measured by X-ray photoelectron spectroscopy (XPS) described later.

[0023] The boron content (boron content in the entire carbon material) of the boron-doped carbon material of the present invention is 0.005 to 15 mol%, preferably 0.01 to 10 mol%, more preferably 0.08 to 5 mol%, and even more preferably 0.1 to 2 mol%. If the boron content is less than 0.005 mol%, the boron doping effect is not obtained, and conductivity is not improved. If the boron content is 15 mol% or more, the excess boron inhibits electron movement, causing a decrease in conductivity. Therefore, good conductivity can be exhibited when the content is in the range of 0.005 to 15 mol%.

[0024] In addition, the carbon material contains boron, which increases wettability with respect to solvents or binder resins, thereby improving the dispersibility of the dispersion. Furthermore, when the boron content is high, the hardness of the carbon material tends to increase, and since durability against external forces such as impact is improved, dispersion stability and film strength are improved. On the other hand, since dispersion tends to become difficult when the boron content is high, from the perspective of the strength and dispersibility of the carbon material, the boron content is preferably 2 mol% or less, and more preferably 1.1 mol% or less.

[0025] The boron content in boron-doped carbon materials can be determined by methods such as ICP emission spectroscopy and ICP mass spectrometry. As an example, a measurement method based on JIS-R7223 can be cited. Furthermore, the boron content in boron-doped carbon materials refers to the total amount of boron, including elemental boron contained on the surface or inside the carbon material, boron doped to substitute carbon elements within the carbon material, and boron compounds.

[0026] Next, the boron doped to substitute carbon elements on the surface of the boron-doped carbon material of the present invention will be described. The content of boron doped to substitute carbon elements on the surface of the boron-doped carbon material can be determined by methods such as X-ray photoelectron spectroscopy (XPS).

[0027] It is known that the B1s spectrum of boron obtained by XPS measurement appears in the binding energy range of the B1s electrons of the boron element (around 185–197 eV) and is broadly composed of four components. Figure 1 is a diagram showing examples of peaks and peak separation of the B1s spectrum in XPS. As shown in Figure 1, the binding energy values ​​(peak tops) of each component are 186–187 eV for the boron cluster, 187–188 eV for boron carbide (B4C), 188–189.3 eV for boron (BC3) doped to be substituted with carbon elements with a hexagonal lattice framework, 189.5–190.5 eV for various boron oxides such as BC2O, 191.5–192 eV for BCO2, and 192.5–193 eV for B2O3. When their peaks overlap, the ratio can be obtained by performing fitting by optimizing each component as a Gaussian function with peak intensity, peak position, and peak full width at half maximum as parameters, and then separating the peaks. Thus, by performing peak separation of B1s, the state of boron on the surface of a boron-doped carbon material can be analyzed.

[0028] Accordingly, the value of the bond energy of the boron doped to substitute carbon atoms on the surface of the boron-doped carbon material of the present invention is 188 to 189.3 eV.

[0029] In addition, when the content of boron elements doped to substitute carbon elements on the surface of the boron-doped carbon material is X and the content of boron elements in the entire boron-doped carbon material is Y, the ratio is preferably X / Y < 0.8, more preferably X / Y < 0.6, and 0.01 <X / Y<0.4이면 한층 더 바람직하고, 0.02<X / Y<0.2이면 보다 바람직하다. X / Y가 0.8이상의 범위에 있으면, 과잉의 홀의 도입에 의해 도전성을 저하시키거나 탄소 재료의 표면에 붕소를 결합 및 / 또는 치환 반응시키기 위해 국소적으로 큰 에너지가 필요하게 되고, 부분적으로 탄소 재료의 육각망면 등의 기본 골격을 무너뜨려 버릴 수도 있다. 이 때문에, X / Y<0.8의 범위에 있으면 양호한 도전성을 발현할 수 있다.

[0030] The data obtained by the aforementioned XPS measurement relates to the surface of the carbon material, and the typical depth resolution is said to be several nm, up to a maximum of 10 nm. On the other hand, the data obtained by ICP measurement relates to the entire carbon material, and the amount of boron calculated by XPS measurement is different from the amount of boron calculated by ICP measurement.

[0031] That is, the carbon material of the present invention is a carbon material having a carbon hexagonal mesh as a basic framework and doped with boron elements to substitute carbon elements, and the boron content in the entire carbon material is within a predetermined range, and the boron content doped to substitute carbon elements on the surface of the carbon material is less than a predetermined value relative to the boron content in the entire carbon material, thereby exhibiting excellent conductivity.

[0032] In addition, the conductive composition using the carbon material of the present invention exhibits excellent conductivity because it not only has excellent dispersibility but also improves durability against external forces such as impact during dispersion, thereby reducing damage to the carbon material.

[0033] In addition, the boron-doped carbon material of the present invention is a carbon material having a carbon hexagonal lattice as its basic framework, which can be confirmed by Raman spectrum measurement and X-ray diffraction measurement.

[0034] Figure 2 is a diagram showing the peaks of the G-band and D-band of a carbon material in a laser Raman spectrum. In Raman spectrum measurements, for example, the G-band (1560–1620 cm⁻¹) due to an excitation laser wavelength of 532 nm -1 By confirming ), it can be verified that it is a carbon material with a carbon hexagonal lattice as the basic framework. In addition, the D-band (1330–1370 cm⁻¹) indicating defects in the carbon material -1 If the strength ratio (G / D ratio) with respect to ) is high, the degree of crystallinity of the boron-doped carbon material is high and the conductivity is also high. It is desirable for the G / D ratio to be 1 or higher, more preferably 1.7 or higher, and even more preferably 2.0 or higher.

[0035] In addition, when the Raman shift of the G-band in the laser Raman spectrum with an excitation laser wavelength of 532 nm is denoted as P and the Raman shift of the D-band as Q, the difference in Raman shift [PQ] is 226 cm⁻¹ -1 If it is less than or equal to this, it is desirable because an increase in carriers leading to improved conductivity due to the boron doping is expected. The difference in Raman shift [PQ] is preferably 218 to 226 cm. -1 and, more preferably, 222~226cm -1 am.

[0036] In X-ray diffraction (XRD) measurements, in the XRD diagram of a boron-doped carbon material obtained using CuKα rays as an X-ray source, it can be confirmed that the carbon material has a carbon hexagonal lattice as its basic framework by confirming the (002) plane diffraction peak that appears at a diffraction angle (2θ) of approximately 24.0 to 27.0°. In addition, the average interplanar distance d002 calculated from the obtained peak is preferably 0.338 nm or less, and more preferably 0.336 nm or less. While the average interplanar distance d002 of general carbon materials tends to have better conductivity when smaller, the average interplanar distance d002 of the boron-doped carbon material of the present invention has excellent conductivity when it is 0.335 to 0.336 nm.

[0037] In addition, the structure (shape) of the boron-doped carbon material of the present invention is not particularly limited as long as it is a carbon material satisfying the above-described conditions, but is classified, for example, carbon black (acetylene black, ketjen black, furnace black, medium thermal carbon black, graphitized carbon black), graphite, graphene nanoplatelet, graphene, carbon fiber, carbon nanotube, carbon nanofiber, carbon nanohorn, carbon nanobrush, activated carbon, porous carbon, nanoporous carbon, etc., and preferably graphitized carbon black, graphite, graphene nanoplatelet, graphene, carbon fiber, carbon nanotube, carbon nanofiber, more preferably graphite, graphene nanoplatelet, graphene, carbon nanotube.

[0038] The average particle diameter of the boron-doped carbon material of the present invention is not particularly limited, but is 0.15 to 500 μm, preferably 0.5 to 100 μm, and more preferably 1 to 50 μm. In addition, the average particle diameter referred to in the present invention is the particle diameter (D50) at the point where the volume ratio of the particles is 50% when the particle diameter is accumulated from the finest particle in the volume particle size distribution, and is measured by a general particle size distribution meter, for example, a dynamic light scattering type particle size distribution meter (MicroTrack UPA manufactured by Nikkisou Co., Ltd.).

[0039] The average thickness of the boron-doped carbon material of the present invention is not particularly limited.

[0040] When the carbon source is graphite, the average thickness is preferably 1 nm to 500 µm, more preferably 150 nm to 50 µm, even more preferably 500 nm to 10 µm, and particularly preferably 500 nm to 5 µm.

[0041] In addition, the average thickness referred to in the present invention may be calculated from the average value of thicknesses randomly extracted using an optical microscope or an electron microscope, or calculated using image analysis. In order to suppress non-uniformity caused by particles, it is preferable to calculate the average value from 100 or more particles.

[0042] In addition, when the carbon source is a carbon nanotube, the average outer diameter is preferably 2 nm to 500 nm, more preferably 3 nm to 250 nm, even more preferably 5 nm to 50 nm, and particularly preferably 5 nm to 25 nm.

[0043] The number of layers of carbon nanotubes is preferably 3 layers or more and 30 layers or less, and more preferably 5 layers or more and 20 layers or less.

[0044] The average outer diameter and number of layers of the carbon nanotubes referred to in the present invention may be calculated from the average value of outer diameters randomly extracted using an electron microscope or the like, or calculated using image analysis or the like. In order to suppress non-uniformity caused by each nanotube, it is preferable to calculate the average value from 100 or more particles.

[0045] Method for manufacturing boron-doped carbon materials

[0046] The method for manufacturing a boron-doped carbon material according to the present invention is not particularly limited, but can be synthesized by heat-treating a carbon source and a boron source. Specifically, it can be synthesized by a method of heat-treating a carbon source of inorganic carbon and a boron source such as a boron compound (e.g., boron carbide), a method of heat-treating a carbon source of petroleum-based compounds (e.g., pitch, tar, coke), a method of heat-treating a boron source such as a boron compound, a method of heat-treating a carbon source such as a synthetic resin and a boron source such as a boron compound, a method of heat-treating a carbon source such as an aromatic hydrocarbon gas and a boron source such as a boron gas on a metal catalyst supported on a substrate to perform chemical vapor deposition (CVD), a method of heat-treating a carbon source such as a hydrocarbon gas and a boron source such as a boron gas on a metal catalyst suspended by spraying to perform catalytic chemical vapor deposition (CCVD), or a method of ion-implanting boron into a carbon source.

[0047] Preferably, the method for manufacturing a boron-doped carbon material according to the present invention is a method of doping boron into a pre-carbonized carbon source. The term "carbonization" as used herein refers to phenomena such as "crystallization" or "graphitization."

[0048] For example, in methods to obtain boron-doped carbon by doping with boron while carbonizing using a non-carbonized carbon source and a boron source, or in methods using a carbon source that has undergone a plastic treatment prior to carbonization, crystallization or graphitization may be insufficient. For this reason, rather than a method of doping with boron while carbonizing, it is preferable to use a method of performing a boron doping reaction after carbonization, such as doping with boron on a carbon source that has been carbonized beforehand, as this allows for the production of a carbon material with a desirable distribution of boron on the surface and inside of the carbon particles. In other words, to obtain the boron-doped carbon material of the present invention that enables the compatibility of excellent conductivity, dispersibility, and durability, the selection of the carbon source and the mixing state of the carbon source and the boron source when the boron doping reaction occurs are also important.

[0049] Next, the carbon source used in the manufacture of boron-doped carbon materials will be described. The carbon source is not particularly limited, but may include inorganic carbon sources and organic carbon sources, and preferably an inorganic carbon source.

[0050] Specific inorganic carbon sources are classified into carbon black (acetylene black, Ketjen black, furnace black, medium thermal carbon black, graphitized carbon black), graphite, graphene nanoplatelets, graphene, carbon fibers, carbon nanotubes, carbon nanofibers, carbon nanohorns, carbon nanobrushes, activated carbon, porous carbon, nanoporous carbon, etc. Preferably, they are graphitized carbon black, graphite, graphene nanoplatelets, graphene, carbon fibers, carbon nanotubes, carbon nanofibers, and more preferably, graphite, graphene nanoplatelets, graphene, and carbon nanotubes. Among the above carbon sources, the size of the carbon hexagonal lattice planes and the stacking structure vary depending on the type or manufacturer. Since various physical properties such as crystallinity, particle diameter, shape, BET specific surface area, pore volume, pore diameter, bulk density, DBP oil absorption, surface acid-base ratio, surface hydrophilicity, and conductivity, as well as costs, differ, the optimal material can be selected to suit the intended use or required performance.

[0051] Commercially available graphite that can be used is not particularly limited, but includes CMX, UP-5, UP-10, UP-20, UP-35N, CSSP, CSPE, CSP, CP, CB-150, CB-100, ACP, ACP-1000, ACB-50, ACB-100, ACB-150, SP-10, SP-20, J-SP, SP-270, HOP, GR-60, LEP, F#1, F#2, F#3, CGC-20, CGC-50, CGB-20, CGB-50, PAG-60, PAG-80, PAG-120, PAG-5, HAG-10W, HAG-150, etc. manufactured by Nippon Kokuen Kogyo Co., Ltd., and EC1500, EC1000, EC500 manufactured by Ito Kokuen Kogyo Co., Ltd. EC300, EC100, EC50, etc., CX-3000, FBF, BF, CBR, SSC-3000, SSC-600, SSC, CX-600, CPF-8, CPF-3, CPB-6S, CPB, 96E, 96L, 96L-3, 90L-3, CPC, S-87, K-3, CF-80, CF-48, CF-32, CP-150, CP-100, CP, HF-80, HF-48, HF-32, SC-120, SC-80, SC-60, SC-32, RA-3000, RA-15, RA-44, GX-600, G-6S, G-3, G-150, G-100 manufactured by Juetsu Kokuen Co., Ltd. Examples include G-48, G-30, G-50, etc., SGP-100, SGP-50, SGP-25, SGP-15, SGP-5, SGP-1, SGO-100, SGO-50, SGO-25, SGO-15, SGO-5, SGO-1, SGX-100, SGX-50, SGX-25, SGX-15, SGX-5, SGX-1, etc., manufactured by SEC Carbon Co., Ltd., and 10099M, PB-99, etc., manufactured by Nishimura Kokuen Co., Ltd.

[0052] In addition, commercially available carbon blacks that can be used are not particularly limited, but include Ketjen Black EC-300J, EC-600JD, Lionite EC-200L manufactured by Lion Specialty Chemicals, Furnace Black #2350, #2600, #3050B, #3030B, #3230B, and #3400B manufactured by Mitsubishi Chemical, and Acetylene Black HS-100, FX-35 manufactured by Denka.

[0053] In addition, commercially available carbon nanotubes that can be used include single-layer carbon nanotubes, two-layer carbon nanotubes, multilayer carbon nanotubes, etc., and are not particularly limited, but examples include VGCF-H and VGCF-X manufactured by Showa Denko, carbon nanotubes manufactured by Meizo Nano Carbon, NTP3003, NTP3021, NTP3121, NTP8012, NTP8022, NTP9012, NTP9112 manufactured by NTP, and TUBALL manufactured by OCSiAl.

[0054] In addition, commercially available graphene-based carbons that can be used are not particularly limited, but examples include graphene nanoplatelets manufactured by XGSciences, such as xGnP-C-300, xGnP-C-500, xGnP-C-750, xGnP-M-5, xGnP-M-15, xGnP-M-25, xGnP-H-5, xGnP-H-15, and xGnP-H-25.

[0055] Among these carbon sources, it is preferable to use graphite, graphene nanoplatelets, graphene, and carbon nanotubes in terms of conductivity or cost, and it is even more preferable to use graphite.

[0056] In addition, specific organic carbon sources are not particularly limited as long as they are organic carbon raw materials that carbonize to become carbon particles after heat treatment, but specifically, examples include phenolic resins, polyimide resins, polyamide resins, polyamideimide resins, polyacrylonitrile resins, polyaniline resins, phenol-formaldehyde resins, polyimidazole resins, polypyrrole resins, polybenzimidazole resins, melamine resins, pitch, coke, lignite, polycarbodiimide, biomass, proteins, humic acid, etc., and derivatives thereof. Among these, the use of pitch or coke, which is also used as a raw material for graphite, is preferred.

[0057] Next, the boron sources used in the manufacture of boron-doped carbon materials will be described. The boron sources are not particularly limited, but examples include boron carbide, boron oxide, boron nitride, metal borides, borooxosic acids, boranes, boron-containing organic compounds, etc.

[0058] Specifically, in boron carbide, B4C(B 12 C3), B 12 C2(B6C), etc.

[0059] In boron oxides, BC2O, BCO2, B2O2, B2O3, B4O3, B4O5, etc.

[0060] In boron nitride, BN, etc.

[0061] In metal borides, AlB2, CoB, FeB, MgB2, NiB, TiB2, etc.

[0062] In boron oxo acids, orthoboric acid, metaboric acid, tetraboric acid, etc.

[0063] In borans, monoboran, diboran, decaboran, etc.

[0064] Examples of boron-containing organic compounds include boric acid esters such as trimethyl borate and triethyl borate, substituted boranes such as triethylborane and triphenylborane, and boronic acids such as phenylboronic acid and phenylboronic acid esters.

[0065] The raw material composition ratio of the carbon source and the boron source for manufacturing the boron-doped carbon material is not particularly limited as long as it can be manufactured to have the boron content described above, but the ratio of the boron source to 100 parts by mass of the carbon source is preferably 0.01 to 300 parts by mass, and more preferably 0.1 to 100 parts by mass.

[0066] The method of mixing the carbon source and boron source is not particularly limited, but preferably involves dry mixing and wet mixing. In addition, as a mixing device, a dry mixing device or a wet mixing device as described below may be used.

[0067] Examples of dry mixing devices include roll mills such as two-roll or three-roll mills, high-speed agitators such as Henschel mixers or super mixers, fluid energy grinders such as micronizers or jet mills, atlasers, particle compounding devices manufactured by Hosokawa Micron, such as "NanoCure," "Nobilta," and "MechanoFusion," and powder surface modification devices manufactured by Naraki Kaisei Sakusho, such as "Hybridization System," "MechanoMicros," and "Millero."

[0068] In addition, when using a dry mixing device, other raw materials may be added directly as powders to the base raw material powder, but to produce a more uniform mixture, other raw materials may be dissolved or dispersed in a small amount of solvent in advance and added while breaking up the aggregated particles of the base raw material powder, and heating may also be used to increase the efficiency of the process.

[0069] Examples of wet mixing devices include, for instance, mixers such as dispersers, homo mixers, or planetary mixers; homogenizers such as "Claire Mix" manufactured by M-Technics or "Peel Mix" manufactured by PRIMIX; paint conditioners manufactured by Red Devil; ball mills; sand mills such as "Dyno Mill" manufactured by Shinmal Enterprises; media-type dispersers such as atlases or coball mills; wet jet mills such as "Genus PY" manufactured by Genus, "Starburst" manufactured by Sugino Machine, or "Nanomizer" manufactured by Nanomizer; media-less dispersers such as "Claire SS-5" manufactured by M-Technics or "Micros" manufactured by Naraki Kaisei Sakusho; or other roll mills, kneaders, ultrasonic dispersers, etc., but are not limited to these. Additionally, as for wet mixing devices, it is preferable to use one that has undergone treatment to prevent metal contamination from the device.

[0070] For example, when using a media-type disperser, it is preferable to use a disperser in which the agitator and vessel are made of ceramic or resin, or to use a disperser in which the surface of the metal agitator and vessel is treated such as by tungsten carbide spraying or resin coating. Also, as the media, it is preferable to use ceramic beads such as glass beads, zirconia beads, or alumina beads. Furthermore, when using a roll mill, it is also preferable to use ceramic rolls. A single type of dispersion device may be used, or a combination of several types of devices may be used.

[0071] In addition, if the raw materials are not uniformly dissolved or dispersed, multiple solvents may be used in combination as needed to improve the wettability and dispersibility of each raw material with respect to the solvent, or a dispersant may be added to disperse and mix.

[0072] In particular, regarding carbonized (graphitized) carbon sources, since it is difficult to uniformly mix boron sources, the mixing (contact) state of the carbon source and boron source when the boron doping reaction occurs is important, and it is desirable to treat the carbon source and boron source uniformly.

[0073] The conditions for heat treatment of the mixture of the carbon source and boron source above vary depending on the type and amount of the carbon source or boron source used as raw material and are not particularly limited, but the heating temperature is 1000 to 3200°C, preferably 1500 to 3000°C, and more preferably 1800 to 2500°C. In addition, the heating time is not particularly limited, but is 10 minutes to 72 hours, and preferably 30 minutes to 10 hours.

[0074] In order to prevent side reactions such as oxidation of the raw material, the atmosphere in the heat treatment process is preferably an inert gas such as nitrogen or argon, or a vacuum atmosphere.

[0075] In addition, the heat treatment process may be a process performed in one step for a constant atmosphere, temperature, and time, as well as a process performed in multiple steps for the atmosphere, temperature, and time.

[0076] Conductive composition

[0077] The conductive composition of the present invention contains at least one of the carbon material described above, a binder resin, or a solvent. The conductive composition may use two or more other types of carbon materials in combination, and may contain a conductive aid if necessary.

[0078] Binder Susie

[0079] As a binder resin, it is not particularly limited and may include at least one type selected from the group consisting of, for example, polyurethane resin, polyamide resin, acrylonitrile resin, acrylic resin, butadiene resin, polyvinyl resin, polyvinyl butyral resin, polyolefin resin, polyester resin, polystyrene resin, EVA resin, polyvinylidene fluoride resin, polytetrafluoroethylene resin, silicone resin, polyether resin, cellulose resin such as carboxymethylcellulose.

[0080] The above binder resin may be used as a single type or in combination of two or more types.

[0081] The binder resin preferably comprises at least one selected from the group consisting of polyurethane-based, polyamide-based, and polyester-based resins in terms of volume resistivity, adhesion to the substrate, and durability, and it is more preferable to include a polyurethane-based resin. The binder resin preferably softens or flows appropriately when a press or heat press (hereinafter referred to as a (heat) press) is applied after printing or coating the conductive composition onto a substrate. By using such a resin, the conductive composition flows in the thickness direction while maintaining the planar pattern shape of the coating film, and a conductive film with low volume resistivity can be obtained because the voids in the film are reduced and the contact points between carbon materials are increased.

[0082] [Polyurethane Resin]

[0083] The method of synthesizing the polyurethane resin is not particularly limited, but examples include a method of reacting a polyol compound (a) with a diisocyanate (b), a method of reacting a polyol compound (a) with a diisocyanate (b) with a diol compound (c) having a carboxyl group to obtain a urethane prepolymer (d) having an isocyanate group, a method of further reacting a polyamino compound (e) with the urethane prepolymer (d), or, in the three methods above, a method of reacting a reaction stopping agent as needed.

[0084] As for the polyol compound (a), various polyether polyols, polyester polyols, polycarbonate polyols, polybutadiene glycols, or mixtures thereof known as polyol components constituting a polyurethane resin may be used.

[0085] Examples of polyether polyols include polymers or copolymers such as ethylene oxide, propylene oxide, and tetrahydrofuran.

[0086] As polyester polyols, saturated and unsaturated low molecular weight diols such as ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, pentanediol, 3-methyl-1,5-pentanediol, hexanediol, octanediol, 1,4-butylenediol, diethylene glycol, triethylene glycol, dipropylene glycol, and dimerdiol, and alkyl glycidyl ethers such as n-butylglycidyl ether and 2-ethylhexylglycidyl ether, monocarboxylic acid glycidyl esters such as versatic acid glycidyl ester, and adipic acid, phthalic acid, isophthalic acid, terephthalic acid, maleic acid, fumaric acid, succinic acid, oxalic acid, malonic acid, glutaric acid, and pimelic acid, Examples include polyester polyols obtained by dehydrating and condensing dicarboxylic acids such as suberic acid, azelaic acid, and sebacic acid, or their anhydrides, or polyester polyols obtained by ring-opening polymerization of cyclic ester compounds.

[0087] As polycarbonate polyols, (1) a reaction product of a diol or bisphenol and a carbonate ester, and (2) a reaction product of a diol or bisphenol with phosgene in the presence of an alkali may be used. Examples of carbonate esters include dimethyl carbonate, diethyl carbonate, diphenyl carbonate, ethylene carbonate, propylene carbonate, etc. Examples of diols include ethylene glycol, propylene glycol, dipropylene glycol, diethylene glycol, triethylene glycol, butylene glycol, 3-methyl-1,5-pentanediol, 2-methyl-1,8-octanediol, 3,3'-dimethylolheptane, polyoxyethylene glycol, polyoxypropylene glycol, propanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,9-nonanediol, neopentyl glycol, octanediol, butylethylpentanediol, 2-ethyl-1,3-hexanediol, cyclohexanediol, 3,9-bis(1,1-dimethyl-2-hydroxyethyl, 2,2,8,10-tetraoxospiro[5.5]undecane, etc. Additionally, examples of bisphenols include bisphenol A or bisphenol F, Examples include bisphenols to which alkylene oxides such as ethylene oxide and propylene oxide have been added.

[0088] The number average molecular weight (Mn) of the above polyol compound is appropriately determined by considering the solubility of the polyurethane resin when preparing the conductive composition, the durability of the formed conductive film, and the adhesion strength to the substrate, but typically, a range of 580 to 8,000 is preferred, and more preferably, a range of 1,000 to 5,000.

[0089] The above polyol compound may be used alone or in combination of two or more types. In addition, within a range where the performance of the polyurethane resin is not lost, a portion of the above polyol compound may be replaced with low molecular weight diols, for example, various low molecular weight diols used in the manufacture of the above polyol compound.

[0090] As the diisocyanate compound (b), aromatic diisocyanates, aliphatic diisocyanates, alicyclic diisocyanates, or mixtures thereof may be used. Preferably, it is an alicyclic diisocyanate, and more preferably, isophorone diisocyanate. Examples of aromatic diisocyanates include 1,5-naphthylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-diphenyldimethylmethane diisocyanate, 4,4'-benzyl diisocyanate, dialkyl diphenylmethane diisocyanate, tetraalkyl diphenylmethane diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, tolylene diisocyanate, xylylene diisocyanate, etc.

[0091] Examples of aliphatic diisocyanates include butane-1,4-diisocyanate, hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, and lysine diisocyanate.

[0092] Examples of cyclocyclocyanates include cyclohexane-1,4-diisocyanate, isophorone diisocyanate, norbornane diisocyanate methyl, bis(4-isocyanate cyclohexyl)methane, 1,3-bis(isocyanate methyl)cyclohexane, and methylcyclohexane diisocyanate.

[0093] Examples of diol compounds (c) having a carboxyl group include dimethylolalkano acids such as dimethylolacetic acid, dimethylolpropionic acid, dimethylolbutanoic acid, and dimethylolpentanoic acid, as well as dihydroxysuccinic acid and dihydroxybenzoic acid. In particular, dimethylolpropionic acid and dimethylolbutanoic acid are preferred in terms of reactivity and solubility.

[0094] When a polyol compound (a), a diisocyanate (b), and a diol compound (c) having a carboxyl group are reacted to obtain a urethane prepolymer (d) having an isocyanate group, the conditions are such that the isocyanate group is in excess, and are not particularly limited otherwise, but it is preferable that the isocyanate group / hydroxyl group equivalent ratio be within the range of 1.05 / 1 to 3 / 1. More preferably, it is 1.2 / 1 to 2 / 1. In addition, the reaction is usually carried out between room temperature and 150°C, and in terms of manufacturing time and control of side reactions, it is preferably carried out between 60°C and 120°C.

[0095] The polyamino compound (e) acts as a chain extender and may use amines having hydroxyl groups, such as ethylenediamine, propylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, isophoronediamine, dicyclohexylmethane-4,4'-diamine, norbornandiamine, 2-(2-aminoethylamino)ethanol, 2-hydroxyethylethylenediamine, 2-hydroxyethylpropylenediamine, di-2-hydroxyethylethylenediamine, and di-2-hydroxypropylethylenediamine. Among these, isophoronediamine is preferably used.

[0096] When synthesizing a polyurethane resin by reacting a urethane prepolymer (d) having an isocyanate group with a polyamino compound (e), a reaction stopping agent may be used in combination to adjust the molecular weight of the polyurethane resin obtained. As reaction stopping agents, dialkylamines such as di-n-butylamine, dialkanolamines such as diethanolamine, or alcohols such as ethanol and isopropyl alcohol may be used.

[0097] The conditions for reacting a urethane prepolymer (d) having isocyanate groups, a polyamino compound (e), and, if necessary, a reaction stopping agent are not particularly limited, but when the free isocyanate groups at both ends of the urethane prepolymer are 1 equivalent, it is preferable that the total equivalent of amino groups in the polyamino compound (e) and the reaction stopping agent is within the range of 0.5 to 1.3. More preferably, it is within the range of 0.8 to 0.995.

[0098] The weight average molecular weight of the polyurethane resin is preferably in the range of 5,000 to 200,000 in terms of coating properties or handling properties.

[0099] [Polyamide Resin]

[0100] Polyamide resin is a general term for polymers having amide bonds obtained through various reactions such as the polycondensation of dibasic acids and diamines, the polycondensation of aminocarboxylic acids, or the ring-opening polymerization of lactams. Various modified polyamides, polymers prepared from partially hydrogenated reactants, polymers in which other monomers are partially copolymerized, or polymers mixed with various additives may be used.

[0101] The polyamide resin is not particularly limited, but a dimer acid-modified polyamide resin obtained by condensing a dibasic acid with a dimer acid as the main component and a polyamine is preferred. As the dimer acid for manufacturing the dimer acid-modified polyamide resin, a dimer acid obtained by polymerizing natural monobasic unsaturated fatty acids contained in tall oil fatty acids, soybean oil fatty acids, etc. is widely used industrially, but in principle, it may also be various dicarboxylic acids such as saturated aliphatic, unsaturated aliphatic, alicyclic, or aromatic acids. Examples of commercially available dimer acids include Hallidimer 200, 300 (manufactured by Harima Casey Co.), Versadime 228, 216, Empol 1018, 1019, 1061, 1062 (manufactured by Cognis Co.). In addition, hydrogenated dimer acids can also be used, and commercially available hydrogenated dimer acids include Prepol 1009 (manufactured by Cloda Japan Co., Ltd.) and Empol 1008 (manufactured by Cognis Co., Ltd.).

[0102] In addition to the above dimer acid, various dicarboxylic acids can be used as dibasic acids because the polyamide resin has suitable flexibility. Specifically, as dicarboxylic acids, oxalic acid, malonic acid, (anhydrous) succinic acid, (anhydrous) maleic acid, glutaric acid, adipic acid, pimelic acid, souveric acid, azelaic acid, sebacic acid, terephthalic acid, isophthalic acid, phthalic acid, naphthalenedicarboxylic acid, 1,3- or 1,4-cyclohexanedicarboxylic acid, 1,18-octadecanedicarboxylic acid, 1,16-hexadecanedicarboxylic acid, etc. are used.

[0103] In addition, a dibasic acid having a phenolic hydroxyl group can also be used. By using a dibasic acid having a phenolic hydroxyl group, a phenolic hydroxyl group can be introduced into the side chain of the polyamide resin and used in the reaction with the curing agent.

[0104] As dibasic acids having a phenolic hydroxyl group, hydroxyisophthalic acids such as 2-hydroxyisophthalic acid, 4-hydroxyisophthalic acid, and 5-hydroxyisophthalic acid; dihydroxyisophthalic acids such as 2,5-dihydroxyisophthalic acid, 2,4-dihydroxyisophthalic acid, and 4,6-dihydroxyisophthalic acid; dihydroxyisophthalic acids such as 2-hydroxyterephthalic acid, 2,3-dihydroxyterephthalic acid, and 2,6-dihydroxyterephthalic acid; hydroxyphthalic acids such as 4-hydroxyphthalic acid and 3-hydroxyphthalic acid; 3,4-dihydroxyphthalic acid; and 3,5-dihydroxyphthalic acid. Examples include dihydroxyphthalic acids such as 4,5-dihydroxyphthalic acid and 3,6-dihydroxyphthalic acid.

[0105] In addition, these acid anhydrides or ester derivatives such as polybasic acid methyl esters can also be cited.

[0106] Among them, 5-hydroxyisophthalic acid is preferred in terms of copolymerization and ease of availability.

[0107] In addition, since the polyamide resin has suitable fluidity when heated, various monocarboxylic acids are used as needed. Specifically, propionic acid, acetic acid, caprylic acid (octanoic acid), stearic acid, oleic acid, etc. are used as monocarboxylic acids.

[0108] The polyamines used as reactants when manufacturing the above dimer acid-modified polyamide resin are, for example, various diamines such as aliphatic, alicyclic, and aromatic ones, triamines, polyamines, etc.

[0109] Specific examples of the above diamines include ethylenediamine, propanediamine, butanediamine, triethylenediamine, tetraethylenediamine, hexamethylenediamine, p- or m-xylenediamine, 4,4'-methylenebis(cyclohexylamine), 2,2-bis-(4-cyclohexylamine), polyglycoldiamine, isophoronediamine, 1,2-, 1,3- or 1,4-cyclohexanediamine, 1,4-bis-(2'-aminoethyl)benzene, N-ethylaminopiperazine, piperazine, etc. In addition, triamines may include diethylenetriamine, etc., and polyamines may include triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, etc. In addition, dimerdiamines obtained by converting a dimerized aliphatic nitrile group and hydrogen reduction may also be used.

[0110] In addition, polyamine compounds may include compounds in which the carboxyl group of a polybasic acid compound having a cyclic or non-cyclic hydrocarbon group having 20 to 48 carbon atoms is converted into an amino group, and examples of commercially available products include “Priamine 1071,” “Priamine 1073,” “Priamine 1074,” and “Priamine 1075” manufactured by Cloder Japan Co., Ltd., and “Versamin 551” manufactured by Cognis Japan Co., Ltd.

[0111] Alkanolamines may be used in combination with diamines. Examples of alkanolamines include ethanolamine, propanolamine, diethanolamine, butanolamine, 2-amino-2-methyl-1-propanol, and 2-(2-aminoethoxy)ethanol. Additionally, polyetherdiamines having oxygen in their backbone may be used. These polyetherdiamines have the general formula H2N-R 1 -(RO) n -R 2 -NH2(where n is 2~100 and R 1 , R 2is an alkyl group or alicyclic hydrocarbon group having 1 to 14 carbon atoms, and R is an alkyl group or alicyclic hydrocarbon group having 1 to 10 carbon atoms. The alkyl group may be in a straight chain or a branched chain. Examples of this etherdiamine include polyoxypropylenediamine, and commercially available products include Zepermin series (manufactured by San Techno Chemical Co., Ltd.). In addition, bis-(3-aminopropyl)-polytetrahydrofuran can also be an example.

[0112] The above polyamines and dimer acids or various dicarboxylic acids are heat-condensed by a conventional method, and various polyamide resins, including dimer acid-modified polyamide resins, are produced by an amidation process accompanied by dehydration. Generally, the reaction temperature is about 100 to 300°C, and the reaction time is about 1 to 8 hours.

[0113] [Polyester Resin]

[0114] Polyester resin is a polymer composed of polycarboxylic acid and polyhydric alcohol as monomers. Known polyester resins may be used, and specifically, in terms of securing the cohesive strength of the resin, it is preferable that the weight average molecular weight be 1,000 to 100,000. In addition, in terms of adhesion, it is preferable that the glass transition temperature be -10℃ to 200℃.

[0115] Examples of polycarboxylic acid components include aromatic dicarboxylic acids, aliphatic dicarboxylic acids, unsaturated dicarboxylic acids, and carboxylic acids with three or more valencies, and one or more of these can be selected and used. Meanwhile, examples of polyalcohol components include aliphatic glycols, ether glycols, and polyalcohols with three or more valencies, and one or more of these can be selected and used.

[0116] Commercially available polyester resins include Byron (manufactured by Toyobo Corporation, "Byron" is a registered trademark), Polyester (manufactured by Nihon Kasei Kagaku Kogyo Co., Ltd., "Polyester" is a registered trademark), and Teslock (manufactured by Hitachi Kasei Polymer Co., Ltd., "Teslock" is a registered trademark).

[0117] As for the binder resin, it is also preferable to include a vinyl polymer having at least one structure selected from the group consisting of polyether, polyester, polycarbonate, and polybutadiene in the side chain, which has a functional group capable of reacting with isocyanate groups, in terms of fluidity upon heating, volume resistivity, adhesion to the substrate, and durability. The method of introducing the side chain is not particularly limited and can be obtained by various synthesis methods.

[0118] Functional groups capable of reacting with isocyanate groups include hydroxyl groups, amino groups, carboxyl groups, epoxy groups, N-methylol groups, N-alkoxymethyl groups, etc., but hydroxyl groups are suitable in terms of reactivity.

[0119] Functional groups capable of reacting with isocyanate groups can be introduced into the side chains or main chains of vinyl polymers, and the method of introduction is not particularly limited and can be introduced by various synthesis methods. When used in applications requiring high toughness and durability, it is preferable to directly introduce functional groups capable of reacting with isocyanates into the main chain of the vinyl polymer, thereby improving the crosslinking density of the resin.

[0120] The weight average molecular weight of the vinyl polymer in terms of polystyrene is preferably 5,000 to 500,000, and more preferably 10,000 to 100,000. When the weight average molecular weight is 500,000 or less, solubility in solvents is improved, and when it is 5,000 or more, sufficient film strength is obtained after (heat)pressing.

[0121] For the binder resin, a curable resin that undergoes a curing (crosslinking) reaction after the binder resin is applied to the substrate may also be used.

[0122] As a crosslinking agent used in curable resins, examples include polyisocyanate compounds having two or more isocyanate groups, although they are not particularly limited. As for polyisocyanate compounds, they are not particularly limited, but when used outdoors, it is preferable to use only alicyclic or aliphatic compounds to prevent the coating film from deteriorating over time.

[0123] Examples of cycloaliphatic polyisocyanate compounds include isophorone diisocyanate, hydrogenated tolylene diisocyanate, and hydrogenated 4,4'-diphenylmethane diisocyanate.

[0124] Examples of aliphatic polyisocyanate compounds include trimethylhexamethylene diisocyanate, 4,4'-diphenylmethane diisocyanate, hexamethylene diisocyanate, lysine diisocyanate, etc.

[0125] Examples of aromatic polyisocyanate compounds include diphenylmethane diisocyanate, tolylene diisocyanate, naphthylene-1,5-diisocyanate, o-xylene diisocyanate, m-xylene diisocyanate, p-xylene diisocyanate, triphenylmethane triisocyanate, polymethylene polyphenyl isocyanate, etc.

[0126] As for the polyisocyanate compound, it is acceptable to use an isocyanate adduct, a biterminal modified compound, or an isocyanurate modified compound of the above compound and glycols or diamines.

[0127] In particular, when the polyisocyanate compound includes an isocyanurate modified body, particularly an isocyanurate ring-containing triisocyanate, it is desirable because sufficient film strength can be obtained after heat pressing. Specifically, examples of isocyanurate ring-containing triisocyanates include isocyanurate-modified isophorone diisocyanate (e.g., Desmodul Z4470 manufactured by Sumitomo Bayer Urethane Co., Ltd.), isocyanurate-modified hexamethylene diisocyanate (e.g., Sumijoul N3300 manufactured by Sumitomo Bayer Urethane Co., Ltd.), and isocyanurate-modified tolylene diisocyanate (e.g., Sumijoul FL-2, FL-3, FL-4, HLBA manufactured by Sumitomo Bayer Urethane Co., Ltd.).

[0128] Polyisocyanate compounds can be used in a ratio in which the total number of isocyanate groups relative to the total number of binder resin functional groups is preferably 0.1 to 5.0 times, more preferably 0.5 to 3.0 times, and particularly preferably 0.8 to 2.0 times, depending on the required performance, as one or more types of polyisocyanate compounds can be used.

[0129] The binder resin may be in the form of a soluble resin that dissolves in a solvent, or a dispersed resin microparticle (emulsion) that does not dissolve in the solvent and exists in the state of microparticles.

[0130] The particle structure of the dispersed resin microparticles may be a multilayer structure, so-called core-shell particles. For example, the curability, drying properties, film-forming properties, and mechanical strength of the binder can be improved by localizing a resin mainly polymerized with monomers having functional groups in the core or shell portions, or by creating differences in Tg or composition between the core and shell. From the perspective of binding properties and particle stability, the average particle diameter of the resin microparticles is preferably 10 to 1000 nm, and preferably 10 to 300 nm. In addition, since particle stability is compromised if a large amount of coarse particles exceeding 1 μm is contained, it is preferable that the amount of coarse particles exceeding 1 μm be no more than 5%.

[0131] In addition, the above average particle diameter refers to the volume-average particle diameter and can be measured by dynamic light scattering. The measurement of the average particle diameter by dynamic light scattering can be performed as follows. Depending on the solid content of the resin fine particles, the solution is diluted 200 to 1000 times with a dispersion medium. Approximately 5 ml of this diluted dispersion is injected into the cell of a measuring device (NanoTrack manufactured by Nikkisho Co., Ltd.), and after inputting the refractive index conditions of the dispersion medium and resin according to the sample, the measurement is performed. The measurement can be made based on the peaks of the volume-average particle diameter distribution data (histogram) obtained at this time.

[0132] As for the dispersed resin microparticles, it is preferable to include cross-linked resin microparticles. Cross-linked resin microparticles refer to resin microparticles having an internal cross-linking structure (three-dimensional cross-linking structure), and it is important that they are cross-linked within the particles. Furthermore, the inclusion of specific functional groups in the cross-linked resin microparticles can contribute to adhesion to the substrate. Additionally, by adjusting the cross-linking structure or the amount of functional groups, a coating film with excellent durability can be obtained.

[0133] From the perspective of environmental burden, etc., water-based solvents, preferably water-soluble resins and water-based resin microparticles that can be used in water are preferred. In addition, from the perspective of slurry stability or coating properties of the conductive composition, it is even more preferable to use water-soluble resins and water-based resin microparticles in combination.

[0134] [Water-soluble resin]

[0135] A water-soluble resin is a resin that can be completely dissolved in water without separation or precipitation after adding 1g of resin to 99g of water at 25°C, stirring, and leaving it at 25°C for 24 hours. Since water-soluble resins have the effect of increasing the dispersibility of carbon materials, a stable composition is obtained with a small amount of resin.

[0136] Water-soluble resins are broadly classified into anionic resins, cationic resins, amphoteric resins that possess both anionic and cationic properties, and other nonionic resins, and it is also acceptable for the resin to be composed of multiple monomers. In addition, water-soluble resins may be used as a single type or in combination of two or more types.

[0137] Examples of anionic resins include resins containing carboxyl groups, sulfonate groups, phosphate groups, and a backbone in which some or all of these have been neutralized. Examples include homopolymers of polymerizable monomers such as (meth)acrylic acid, itaconic acid, fumaric acid, maleic acid, 2-sulfoethyl methacrylate, and 2-methacryloyl oxyethyl acid phosphate, copolymers with other polymerizable monomers, carboxymethylcellulose, and alkali-neutralized products thereof.

[0138] Examples of cationic resins include resins containing cyclic amino groups, a backbone in which some or all of the amino groups have been neutralized, or quaternary ammonium salts. Examples include homopolymers of polymerizable monomers such as N,N-dimethylaminoethyl (meth)acrylate, N,N-diethyl (meth)acrylate, and vinylpyridine, copolymers with other polymerizable monomers, and their acid neutralization products.

[0139] Examples of positive resins include resins containing both the anionic backbone and the cationic backbone. Examples include copolymers of styrene-maleic acid-N,N-dimethylaminoethyl(meth)acrylate.

[0140] The nonionic resin is a resin other than the anionic, cationic, and amphoteric resins mentioned above. Examples include polyvinylpyrrolidone, polyvinyl alcohol, polyvinyl butyral, polyacrylamide, poly-N-vinylacetamide, polyalkylene glycol, etc.

[0141] The molecular weight of the water-soluble resin is not particularly limited, but preferably, the mass average molecular weight is 5,000 to 2,500,000. The mass average molecular weight (Mw) refers to the molecular weight equivalent to polyethylene oxide in gel permeation chromatography (GPC).

[0142] [Water-based resin microparticles]

[0143] Aqueous resin microparticles (aqueous emulsions) are dispersed resin microparticles in which the resin does not dissolve in water but exists in a microparticle state. Examples include (meth)acrylic emulsions, nitrile emulsions, urethane emulsions, polyolefin emulsions, fluorine emulsions (such as polyvinylidene fluoride (PVDF) or polytetrafluoroethylene (PTFE)), and diene emulsions (such as styrene-butadiene rubber (SBR)). Additionally, (meth)acrylic refers to methacrylic or acrylic.

[0144] A conductive composition containing aqueous resin microparticles can provide a coating film with excellent adhesion between particles and to the substrate, and high strength when a coating film is formed. Furthermore, since the required aqueous resin microparticles are sufficiently small due to the excellent adhesion, the conductivity of the conductive composition is improved. To obtain the effects described above, (meth)acrylic emulsions or urethane emulsions with excellent inter-particle bonding and flexibility (film flexibility) are preferred as aqueous resin microparticles.

[0145] A (meth)acrylic emulsion is an emulsion polymer containing 10 parts by mass or more of a monomer having a (meth)acryloyl group, preferably 20 parts by mass or more, and more preferably 30 parts by mass or more. Since monomers having an acryloyl group have excellent reactivity, resin microparticles can be manufactured relatively easily. Therefore, (meth)acrylic emulsions are particularly preferred as aqueous resin microparticles.

[0146] <Solvent>

[0147] In the conductive composition of the present invention, a solvent may be appropriately used when dispersing a carbon material or when uniformly mixing a carbon material with a binder resin. Such a solvent is not particularly limited as long as it is capable of dissolving the resin or stably dispersing the resin fine particle emulsion, and examples include water or organic solvents.

[0148] Organic solvents may be selected from alcohols such as methanol, ethanol, propanol, butanol, ethylene glycol methyl ether, and diethylene glycol methyl ether; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ethers such as tetrahydrofuran, dioxane, ethylene glycol dimethyl ether, and diethylene glycol dimethyl ether; hydrocarbons such as hexane, heptane, and octane; aromatics such as benzene, toluene, xylene, and cumene; and esters such as ethyl acetate and butyl acetate, depending on the composition of the conductive composition.

[0149] In addition, the solvent may be a combination of water and an organic solvent, or a combination of two or more organic solvents.

[0150] When using water-soluble resins or aqueous resin microparticles, it is preferable to use water as a solvent for the sake of solubility or dispersibility, and if necessary, a liquid medium compatible with water may be added. As a liquid medium compatible with water, an alcohol-based solvent having 4 or fewer carbon atoms is preferred.

[0151] In addition, the resin composition of the present invention may include various additives such as ultraviolet absorbers, ultraviolet stabilizers, radical supplements, fillers, thixotropy-imparting agents, anti-aging agents, antioxidants, antistatic agents, flame retardants, thermal conductivity modifiers, plasticizers, anti-slip agents, antifouling agents, preservatives, fungicides, defoaming agents, leveling agents, anti-blocking agents, curing agents, thickeners, dispersants, and silane coupling agents, provided that they do not interfere with the effects of the present invention.

[0152] <Two or more other types of carbon materials>

[0153] As described above, the conductive composition of the present invention may include two or more different carbon materials among the carbon materials of the present invention.

[0154] The combination of two or more different carbon materials is not particularly limited, but preferably includes the combined use of two or more carbon materials with different specific surface areas; the combined use of two or more carbon materials with different types of carbon, such as graphite and carbon black, graphite and carbon nanotubes, graphite and graphene (graphene nanoplatelets); or a combination thereof.

[0155] When two or more types of carbon materials with different specific surface areas are used together, the specific surface area of ​​the carbon material with the largest specific surface area is preferably 5 to 1500 m² / g, more preferably 20 to 1300 m² / g, and even more preferably 110 to 900 m² / g.

[0156] It is presumed that the conductive film formed from a conductive composition comprising two or more carbon materials according to the present invention is uniform, has high packing properties between carbon materials, and is a high-density conductive film, thereby improving the conductive network between carbon materials within the film and the durability of the conductive film. Furthermore, it is presumed that by using two or more carbon materials in combination, wettability is improved, the interaction with the binder resin changes, and as it becomes difficult for the binder resin to coat the surface of the carbon materials, it becomes difficult for the binder resin to exist at the contact points between the carbon materials, thereby reducing the contact resistance of the carbon materials. Additionally, by using two or more carbon materials in combination, viscosity tends to decrease due to improved dispersibility, which makes handling of the dispersed material easier and further improves coating properties.

[0157] It is presumed that, through this action, a highly conductive film can be formed by using two or more different types of carbon materials.

[0158] <Challenge Aid>

[0159] The conductive composition of the present invention may additionally contain a conductive agent other than the carbon material of the present invention, if necessary. The conductive agent may be one that does not correspond to the specific boron-doped carbon material of the present invention, and examples include carbon agents such as carbon black, activated carbon, graphite, conductive carbon fibers (carbon nanotubes, carbon nanofibers, etc.), carbon nanohorns, graphene, graphene nanoplatelets, nanoporous carbon, and metal agents such as metal nanoparticles (silver, copper, etc.). The conductive agent may contain boron or may be doped with boron.

[0160] In terms of specific surface area and particle diameter, carbon black is preferably used as a conductive agent. Additionally, carbon black, activated carbon, graphite, conductive carbon fibers (carbon nanotubes, carbon nanofibers, etc.), carbon nanohorns, graphene, graphene nanoplatelets, and nanoporous carbon can be used as described above.

[0161] It is preferable that the conductive agent has a larger specific surface area than the carbon material of the present invention, which is the conductive subject. The preferred specific surface area of ​​the conductive agent is preferably 5 to 1500 m² / g, more preferably 20 to 1300 m² / g, and even more preferably 110 to 900 m² / g. If the specific surface area of ​​the conductive agent is 1500 m² / g or less, the dispersibility of the conductive composition is good, and if the specific surface area is 5 m² / g or more, the gaps between the conductive subjects in the conductive film can be efficiently filled, and a conductive film with excellent conductivity and durability can be obtained.

[0162] In addition, the specific surface area of ​​the present invention refers to the specific surface area (BET) obtained from the amount of nitrogen adsorbed.

[0163] The proportion of the boron-doped carbon material of the present invention comprising the total solid content of the conductive composition is preferably 50 to 99 mass%, and more preferably 50 to 80 mass%. If the above-described boron-doped carbon material is 50 mass% or more, contact between carbon materials within the conductive film increases, thereby obtaining good conductivity. On the other hand, if the above-described boron-doped carbon material is 99 mass% or less, it is preferable because durability, such as adhesion of the conductive film, is not reduced.

[0164] When two or more different types of the aforementioned boron-doped carbon materials are used in combination, the proportion of the aforementioned boron-doped carbon material having the largest specific surface area in the total solid content of the conductive composition is preferably 1 to 40 mass%, more preferably 5 to 30 mass%, and even more preferably 10 to 20 mass%.

[0165] When the conductive composition further includes a conductive aid, the proportion of the boron-doped carbon material of the present invention in the total solid content of the conductive composition is preferably 40 to 90 mass%, more preferably 45 to 80 mass%, and even more preferably 50 to 60 mass%.

[0166] Meanwhile, the proportion of the conductive aid in the total solid content of the conductive composition is preferably 1 to 40 mass%, more preferably 5 to 30 mass%, and even more preferably 10 to 20 mass%.

[0167] The viscosity of the conductive composition can be appropriately adjusted by the coating method of the conductive composition, but generally, it is preferable to have a viscosity of 10 mPa·s or more and 30,000 mPa·s or less. The above viscosity can be measured, for example, using a Type B viscometer.

[0168] As described above, the viscosity of a dispersion containing a boron-containing carbon additive as a conductive additive tends to decrease compared to the case where a dispersion is prepared with a carbon additive that does not contain boron, because the surface condition of the carbon additive changes. This results in the effect of making the dispersion easier to handle.

[0169] (Disperser / Mixer)

[0170] As devices used to obtain a conductive composition, dispersers and mixers commonly used for pigment dispersion, etc., may be used.

[0171] Examples include mixers such as dispersers, homo mixers, or planetary mixers; homogenizers such as "Claire Mix" manufactured by M Technics or "Fil Mix" manufactured by PRIMIX; media-type dispersers such as paint conditioners (manufactured by Red Devil), ball mills, sand mills ("Dyno Mill" manufactured by Shinmaru Enterprises, etc.), art retists, pearl mills ("DCP Mill" manufactured by Eilish, etc.), or CoBall Mills; media-less dispersers such as wet jet mills ("Ginas PY" manufactured by Ginas, "Starburst" manufactured by Sugino Machine, "Nanomizer" manufactured by Nanomizer, etc.), "Claire SS-5" manufactured by M Technics or "MICROS" manufactured by Narakikai; or other roll mills, kneaders, ultrasonic dispersers, etc., but are not limited to these.

[0172] For example, when using a media-type disperser, it is preferable to use a disperser in which the agitator and vessel are made of ceramic or resin, or to use a disperser in which the surface of the metal agitator and vessel is treated such as by tungsten carbide spraying or resin coating. Also, as the media, it is preferable to use ceramic beads such as glass beads, zirconia beads, or alumina beads. A single type of dispersion device may be used, or a combination of multiple types of devices may be used.

[0173] <Challenge>

[0174] The conductive film of the present invention is a film formed from a conductive composition, and can be formed by coating a conductive composition on a substrate and drying it as needed.

[0175] (write)

[0176] The shape of the substrate used for forming the conductive film is not particularly limited, and one suitable for the application can be appropriately selected. The substrate is preferably in the shape of a sheet, and more preferably is an insulating resin film.

[0177] The material of the substrate is not particularly limited, and examples include PET (polyethylene terephthalate), PEN (polyethylene naphthalate), polyimide, polyvinyl chloride, polyamide, nylon, OPP (oriented polypropylene), and CPP (unoriented polypropylene).

[0178] In addition, regarding the shape, a flat film is generally used, but a surface roughened, primer-treated, perforated, and mesh-shaped substrate can also be used.

[0179] There are no particular restrictions on the method of coating a conductive composition onto a substrate, and known methods may be used. Examples of such coating methods include die coating, dip coating, roll coating, doctor coating, knife coating, spray coating, gravure coating, screen printing, and electrostatic coating. Examples of drying methods include standing drying, blow drying, hot air drying, infrared heating, and far-infrared heating, but are not specifically limited to these.

[0180] In addition, rolling treatment using a flat plate press or a calender roll may be performed after coating, and since the conductive film is softened to make it easier to press, the rolling treatment may be performed while heating.

[0181] The thickness of the conductive film is generally 0.1 μm or more and 1 mm or less, and preferably 1 μm or more and 200 μm or less.

[0182] (Volume resistivity of the conductive film)

[0183] The volume resistivity of the conductive film of the present invention is preferably 5×10 -3 It is less than Ω·cm, and more preferably 2×10 -3 It is less than Ω·cm, and more preferably 1×10⁻⁶ -3 It is less than Ω·cm. The volume resistivity is 5×10 -3By having less than Ω·cm, it is a highly conductive composition that can be used as an electrode of a battery, a current collector, a battery, wiring for electronic devices, etc.

[0184] <Capacitor Device>

[0185] The conductive composition of the present invention can be a composition for forming a positive electrode or a negative electrode for a capacitor device by incorporating an active material, etc., as needed. And, a capacitor device can be obtained by using at least one of the positive electrode or the negative electrode formed by the composition for forming the positive electrode or the negative electrode.

[0186] Examples of such energy storage devices include secondary batteries and capacitors. Examples of secondary batteries include lithium-ion secondary batteries, sodium-ion secondary batteries, magnesium secondary batteries, alkaline secondary batteries, lead-acid batteries, sodium-sulfur secondary batteries, lithium-air secondary batteries, etc. Examples of capacitors include electric double layer capacitors and lithium-ion capacitors.

[0187] The structure of the above secondary battery and capacitor is not particularly limited, but typically consists of a positive electrode and a negative electrode and a separator formed as needed, and can be selected from various shapes depending on the purpose of use, such as paper type, cylindrical type, button type, and stacked type.

[0188] [Combined Ink]

[0189] Next, a composite ink comprising an active material, which is one of the suitable embodiments as a composition for forming a positive or negative electrode for the above-mentioned capacitor device, will be described.

[0190] The composite ink includes a positive electrode composite ink or a negative electrode composite ink, and the conductive composition includes an active material for the positive or negative electrode, and, if necessary, may additionally include a binder resin, a solvent, and other additive agents.

[0191] (Active material)

[0192] As a positive electrode active material for a lithium-ion secondary battery, metal compounds such as metal oxides or metal sulfides capable of doping or intercalating lithium ions, and conductive polymers can be used, although not particularly limited.

[0193] Examples include inorganic compounds such as oxides of transition metals like Fe, Co, Ni, and Mn, complex oxides with lithium, and transition metal sulfides. Specifically, MnO, V2O5, and V6O 13 Examples include transition metal oxide powders such as TiO2, layered lithium nickelate, lithium cobaltate, lithium manganate, ternary active materials which are complex oxides of nickel, cobalt, manganese, and lithium, complex oxides of lithium and transition metals such as lithium manganate with a spinel structure, lithium iron phosphate-based materials which are olivine-structured phosphate compounds, and transition metal sulfide powders such as TiS2 and FeS.

[0194] In addition, conductive polymers such as polyaniline, polyacetylene, polypyrrole, and polythiophene may be used. Furthermore, the above-mentioned inorganic or organic compounds may be mixed and used.

[0195] As a negative electrode active material for lithium-ion secondary batteries, it is not particularly limited as long as it is capable of doping or intercalating lithium ions. For example, metallic Li, alloy systems such as tin alloys, silicon alloys, and lead alloys, and Li X Fe2O3, Li X Fe3O4, Li XExamples of negative electrode active materials include metal oxide-based materials such as WO2, lithium titanate, lithium vanadate, and lithium silicate; conductive polymer-based materials such as polyacetylene and poly-p-phenylene; amorphous carbonaceous materials such as soft carbon or hard carbon; carbonaceous powders such as artificial graphite such as highly graphitized carbon materials or natural graphite; carbon-based materials such as carbon black, mesophase carbon black, resin-fired carbon materials, substrate-grown carbon fibers, and carbon fibers. These negative electrode active materials may be used in one type or in combination of multiple types.

[0196] In addition, as positive and negative active materials for alkaline secondary batteries, conventionally known materials can be appropriately selected.

[0197] As electrode active materials for electric double layer capacitors, examples include activated carbon, polyacene, carbon whiskers, and graphite, although they are not particularly limited, and powders or fibers thereof may be used. A preferred electrode active material for electric double layer capacitors is activated carbon, and specifically, examples include activated carbon that has been activated from phenolic, yashigara, rayon, acrylic, coal / petroleum-based pitch coke, and mesocarbon micro beads (MCMB).

[0198] As a positive electrode active material for a lithium-ion capacitor, any material capable of reversibly doping and undoping lithium ions and anions is not particularly limited, and for example, activated carbon powder can be used.

[0199] As a negative electrode active material for a lithium-ion capacitor, any material capable of reversibly doping and undoping lithium ions is not particularly limited, and examples include graphite-based materials such as artificial graphite and natural graphite.

[0200] (Binder resin)

[0201] As for the binder resin that may contain the composite ink, the description in the <Binder Resin> column above may be used. In addition, the above binder resin may include, for example, acrylic resin, polyurethane resin, polyester resin, phenolic resin, epoxy resin, phenoxy resin, urea resin, melamine resin, alkyd resin, formaldehyde resin, silicone resin, fluoropolymer resin, cellulose resin such as carboxymethyl cellulose, synthetic rubber such as styrene-butadiene rubber or fluororubber, conductive resin such as polyaniline or polyacetylene, and polymer compounds containing fluorine atoms such as polyvinylidene fluoride, polyvinyl fluoride, and tetrafluoroethylene, and may be modified products, mixtures, or copolymers of these resins. These binders may be used in combination of one type or multiple types.

[0202] In addition, dispersants, film-forming agents, defoaming agents, leveling agents, preservatives, pH adjusters, viscosity adjusters, etc., may be incorporated into the composite ink as needed.

[0203] The viscosity of the composite ink can be appropriately adjusted by the coating method, but typically, it is preferable to have a viscosity of 100 mPa·s or more and 30,000 mPa·s or less within the range of 30 to 90 mass% of solid content.

[0204] Within the viscosity range suitable for coating, it is preferable that the content of the active material be as high as possible, and the ratio of the active material to the solid content of the composite ink is preferably 80 to 99 mass%. In addition, it is preferable that the ratio of the carbon material of the present invention to the solid content of the composite ink is 0.01 to 15 mass%.

[0205] (Disperser / Mixer)

[0206] As devices used to obtain composite ink, dispersers and mixers commonly used for pigment dispersion, etc., may be used.

[0207] [electrode]

[0208] At least one electrode of the positive or negative electrode used in a capacitor device can be obtained by coating and drying the composite ink on a current collector to form a composite layer.

[0209] (Whole house)

[0210] The material or shape of the current collector used for the electrode is not particularly limited, and one from various capacitor devices can be appropriately selected. For example, metals or alloys such as aluminum, copper, nickel, titanium, or stainless steel can be used as materials for the current collector. In the case of lithium-ion batteries, aluminum is preferred as the positive electrode material, and copper is preferred as the negative electrode material.

[0211] [Electrolyte]

[0212] The electrolyte can be appropriately selected from known materials. For example, as an electrolyte used in a lithium-ion secondary battery, an electrolyte containing lithium can be dissolved in a non-aqueous solvent.

[0213] The above electrolyte is not particularly limited and may include, for example, LiBF4, LiClO4, LiPF6, LiAsF6, LiSbF6, LiCF3SO3, Li(CF3SO2)2N, LiC4F9SO3, Li(CF3SO2)3C, LiI, LiBr, LiCl, LiAlCl, LiHF2, LiSCN, or LiBPh4.

[0214] The above-mentioned non-aqueous solvents are not particularly limited and may include, for example, carbonates such as ethylene carbonate, propylene carbonate, butylene carbonate, dimethyl carbonate, ethyl methyl carbonate, and diethyl carbonate; lactones such as γ-butyrolactone, γ-valerolactone, and γ-octanoic lactone; glymes such as tetrahydrofuran, 2-methyltetrahydrofuran, 1,3-dioxolane, 4-methyl-1,3-dioxolane, 1,2-methoxyethane, 1,2-ethoxyethane, and 1,2-dibutoxyethane; esters such as methyl formate, methyl acetate, and methylpropionate; sulfoxides such as dimethyl sulfoxide and sulfolane; and nitriles such as acetonitrile.

[0215] These solvents may be used individually or in combination of two or more.

[0216] In addition, the above electrolyte may be retained in a polymer matrix to form a gel-like polymer electrolyte. Examples of polymer matrices include acrylate-based resins having polyalkylene oxide segments, polyphosphazene-based resins having polyalkylene oxide segments, and polysiloxanes having polyalkylene oxide segments, but are not limited to these.

[0217] In addition, as long as it is capable of ion conduction, a solid electrolyte may be used instead of an electrolyte solution. Such solid electrolytes are not particularly limited, and examples include oxide-based solid electrolytes or sulfide-based solid electrolytes.

[0218] [Separator]

[0219] Examples of separators include polyethylene nonwoven fabrics, polypropylene nonwoven fabrics, polyamide nonwoven fabrics, and those treated with hydrophilicity, but are not specifically limited to these.

[0220] Example of implementation

[0221] The present invention will be explained in more detail below by way of examples. Also, parts and % represent parts by mass and mol%, respectively, unless specifically stated otherwise.

[0222] Manufacture of carbon materials

[0223] [Example A1]

[0224] 84 parts of granular natural graphite CGB-20 (manufactured by Nippon Kokuen Kogyo Co., Ltd.), which is a carbon source, and 16 parts of boric acid (manufactured by Fujifilm Wako Junyaku Co., Ltd.), which is a boron source, were dry-mixed using a ball mill to produce a precursor (1).

[0225] Next, the precursor (1) is filled into a graphite crucible and heat-treated at 2100°C for 1 hour under an argon atmosphere in a kiln to obtain a carbon material (1).

[0226] [Example A2]

[0227] 15 parts of boric acid, which is a boron source, were dissolved in 30 parts of water and 270 parts of ethanol, which are solvents, and then 85 parts of granular natural graphite CGB-50 (manufactured by Nippon Kokuen Kogyo Co., Ltd.), which is a carbon source, were added and stirred using a planetary mixer and wet mixed. Subsequently, the solvent was evaporated at 80°C to produce a precursor (2).

[0228] Next, the precursor (2) is filled into a graphite crucible and heat-treated at 2100°C for 1 hour under an argon atmosphere in a kiln to obtain a carbon material (2).

[0229] [Examples A3~A7, Comparative Examples A1~A3]

[0230] Carbon materials (3) to (10) were produced using the raw materials and conditions shown in Table 1, in the case where the raw materials were dry mixed, in the same manner as Example A1, and in the case where the raw materials were wet mixed, in the same manner as Example A2.

[0231] [Comparison Example A4]

[0232] For 100 parts of the carbon source, multilayer graphene (graphene nanoplatelet) xGnP-C-750 (manufactured by XG Sciences), doping was performed by ionizing boron using an ion implantation device, and a carbon material (11) was obtained.

[0233] Evaluation of Carbon Materials

[0234] The following evaluation was performed on the carbon material described above. The results are shown in Table 2.

[0235] (Boron element content on the surface of carbon materials)

[0236] The boron content (%) on the surface of the carbon material was measured using XPS (manufactured by Thermo Fisher Scientific, K-Alpha).

[0237] Since the spectrum of boron 1s electrons appears with a binding energy of 185–194 eV, the content of boron elements on the surface can be quantified by calculating the peak area. In addition, specifically, boron clusters appear at 186–187 eV, boron carbides at 187–188 eV, boron elements (BC3) doped to be substituted with carbon elements with a hexagonal lattice framework at 188–189.3 eV, various boron oxides such as BC2O at 189.5–190.5 eV, BCO2 at 191.5–192 eV, and B2O3 at 192.5–193 eV (see Fig. 1).

[0238] Therefore, by performing boron 1s peak separation, the doping state of boron on the surface of the carbon material can be analyzed.

[0239] (Boron content in carbon materials)

[0240] The content (%) of boron element in the carbon material was measured using ICP emission spectroscopic analysis (SPECTROARCOS FHS12 manufactured by SPECTRO). The obtained value represents the amount (%) of boron element contained in the entire carbon material.

[0241] (Volume resistivity of carbon materials)

[0242] The volume resistivity of the carbon material was measured using a powder resistance measurement system (MCP-PD51 type manufactured by Mitsubishi Chemical Analytica). The volume resistivity is the value obtained when a load of 20 kN is applied after the carbon material is placed in the measurement cell.

[0243] (Basic framework of the carbon hexagonal mesh of carbon materials)

[0244] By using an X-ray diffraction device (manufactured by Rigaku Co., Ltd., Smartlab) and measuring with CuKα rays as the X-ray source, a peak of the (002) plane derived from the graphite framework was confirmed around 2θ=24.0~27.0°, and it was confirmed that carbon materials (1)~(11) and (12)~(45) have a basic framework of carbon hexagonal lattice planes.

[0245] [Table 1]

[0246]

[0247] [Table 2]

[0248]

[0249] [Example A8]

[0250] A catalyst (1) for synthesizing carbon nanotubes (CNT) was prepared by the method described in paragraphs

[0147] and

[0148] of Japanese Patent Publication No. 2019-108256. Then, a heat-resistant dish made of quartz glass, on which 1g of the catalyst for synthesizing CNT was sprinkled, was installed in the center of a horizontal reaction tube with a volume of 10L, which is pressurizable and heatable by an external heater. Evacuation was performed while injecting nitrogen gas, the air inside the reaction tube was replaced with nitrogen gas, and the atmosphere temperature inside the horizontal reaction tube was heated until it reached 700°C. After reaching 700°C, ethylene gas as a hydrocarbon was introduced into the reaction tube at a flow rate of 2L per minute, and a contact reaction was carried out for 15 minutes. After the reaction was finished, the gas inside the reaction tube was replaced with nitrogen gas, and the CNT (1) was obtained by cooling the reaction tube until the temperature was 100°C or lower and removing it.

[0251] Next, 96 parts of carbon source CNT (1), 4 parts of boron source boric acid (manufactured by Fujifilm Wako Junyaku Co., Ltd.), 9,500 parts of solvent NMP (N-methylpyrrolidone), and 400 parts of ethanol were uniformly dispersed using an ultrasonic homogenizer (Advanced Digital, Sonifer (registered trademark), MODEL 450DA, manufactured by BRANSON Co., Ltd.) and then dried to produce a precursor (12). Also, in Tables 3 and 7, the mixing method for the precursor (12) is indicated as treatment (1).

[0252] Next, the precursor (12) is filled into a graphite crucible and heat-treated at 1750°C for 1 hour under an argon atmosphere in a kiln to obtain a carbon material (12).

[0253] [Examples A9, A10]

[0254] Carbon materials (13) and (14) were produced in the same manner as Example A8, except that the raw materials and conditions shown in Table 3 were used.

[0255] [Example A11]

[0256] 95 parts of carbon source CNT (2) (multilayer carbon nanotube 100P, manufactured by KUMHO PETROCHEMICAL), 5 parts of boron source boric acid (manufactured by Fujifilm Wako Junyaku Co.), 9500 parts of solvent NMP, 400 parts of ethanol, and 0.9 parts of dispersant PVP (1) (polyvinylpyrrolidone, K-15, manufactured by Sigma-Aldrich) were uniformly dispersed using an ultrasonic homogenizer and then dried to produce a precursor (15). Also, in Tables 3 and 7, the mixing method for the precursor (15) is indicated as treatment (2).

[0257] Next, a precursor (15) is filled into a graphite crucible and heat-treated at 1700°C for 1 hour under an argon atmosphere in a kiln to obtain a carbon material (15).

[0258] [Example A12]

[0259] 96.2 parts of carbon source CNT (3) (multilayer carbon nanotube JENOTUBE 8S, manufactured by JEO), 3.8 parts of boron source boric acid (manufactured by Fujifilm Wako Junyaku Co.), 9500 parts of solvent NMP, 400 parts of ethanol, and 0.8 parts of dispersant PVP (1) were uniformly dispersed using an ultrasonic homogenizer, and after drying the solvent, composites were performed using a particle composite device Mechanofusion (manufactured by Hosokawa Micron Co.) to produce a precursor (16). In addition, in Tables 3 and 7, the same mixing method as that of the precursor (16) is indicated as treatment (3).

[0260] Next, a precursor (16) is filled into a graphite crucible, and heat treatment is performed at 1700°C for 1 hour under an argon atmosphere in a kiln to obtain a carbon material (16).

[0261] [Example A13]

[0262] A carbon material (17) was produced in the same manner as Example A12, except that the raw materials and conditions shown in Table 3 were used.

[0263] [Comparison Example A5]

[0264] 99.5 parts of carbon source CNT (4) (manufactured by OCSiAl, carbon nanotube TUBALL) and 0.5 parts of boron source boron carbide (manufactured by Fujifilm Wako Junyaku Co.) were mixed in an agate mortar, filled into a graphite crucible, and heat treated at 2800°C for 20 minutes under an argon atmosphere in a kiln to obtain a carbon material (18).

[0265] [Comparison Example A6]

[0266] A carbon material (19) was produced in the same way as Comparative Example A5, except that the raw materials and conditions shown in Table 3 were used.

[0267] [Comparison Example A7]

[0268] A heat-resistant dish made of quartz glass, on which 1 g of catalyst (1) for CNT synthesis was sprinkled, was installed in the center of a horizontal reaction tube with a volume of 10 L, which is pressurizable and heatable by an external heater. Exhaust was performed while injecting nitrogen gas, and the air inside the reaction tube was replaced with nitrogen gas, and the atmosphere temperature inside the horizontal reaction tube was heated until it reached 700°C. After reaching 700°C, a mixed gas of ethylene gas and trimethyl borate gas was introduced into the reaction tube at a flow rate of 2 L per minute, and a contact reaction was carried out for 15 minutes. After the reaction was finished, the gas inside the reaction tube was replaced with nitrogen gas, and the temperature of the reaction tube was cooled until it was 100°C or lower to obtain a carbon material (20).

[0269] [Comparison Example A8]

[0270] Carbon black (CB(1)) (Ketjen Black EC-600JD, manufactured by Lion Specialty Chemicals) was doped by ionizing boron using an ion implantation device to obtain a carbon material (21).

[0271] Regarding the carbon material described above, the <Evaluation of Carbon Material> described above was performed. The evaluation results are shown in Table 4.

[0272] [Table 3]

[0273]

[0274] [Table 4]

[0275]

[0276] [Example A14]

[0277] 99 parts of carbon source UP-20 (natural graphite, manufactured by Nippon Kokuen Kogyo Co., Ltd.), 1 part of boron source boric acid (manufactured by Fujifilm Wako Junyaku Co., Ltd.), 1800 parts of solvent toluene, and 200 parts of ethanol were put into a mixer and mixed, then put into a sand mill and dispersed.

[0278] A dispersion was sampled and the dispersion was continued until the average thickness of the carbon of the precursor was 90 nm, after which the solvent was dried to produce the precursor (22). Also, in Table 5, the mixing method for the precursor (22) is indicated as treatment (4).

[0279] Next, the precursor (22) is filled into a graphite crucible and heat-treated at 2100°C for 1 hour under an argon atmosphere in a kiln to obtain a carbon material (22).

[0280] [Examples A15, A16]

[0281] Carbon materials (23) and (24) were produced in the same manner as in Example A14, except that the average thickness of the carbon of the precursor was dispersed to be 355 nm and 825 nm, respectively.

[0282] [Example A17]

[0283] 98.8 parts of carbon source F#1 (natural graphite, manufactured by Nippon Kokuen Kogyo Co., Ltd.), 1.2 parts of boron source boron carbide (manufactured by Fujifilm Wako Junyaku Co., Ltd.), 1000 parts of solvent toluene, and 0.1 parts of dispersant PVP (1) were mixed in a mixer and then dispersed in a sand mill.

[0284] A dispersion was sampled and the dispersion was continued until the average thickness of the carbon of the precursor was 3.5 μm, after which the solvent was dried to produce the precursor (25). Also, in Table 5, a mixing method similar to that of the precursor (25) is indicated as treatment (5).

[0285] Next, a precursor (25) is filled into a graphite crucible and heat-treated at 2000°C for 1 hour under an argon atmosphere in a kiln to obtain a carbon material (25).

[0286] [Example A18]

[0287] A carbon material (26) was produced in the same manner as Example A17, except that the carbon of the precursor was dispersed to an average thickness of 11.6 μm.

[0288] [Comparison Example A9]

[0289] 92 parts of petroleum coke, which is a carbon source, and 8 parts of boron oxide (manufactured by Fujifilm Wako Junyaku Co., Ltd.), which is a boron source, were mixed in a mortar and then filled into a graphite crucible and heat-treated at 2800°C for 1 hour under an argon atmosphere in a kiln to obtain a carbon material (27).

[0290] Regarding the carbon material described above, the <Evaluation of Carbon Material> described above and the following evaluation were performed. The results are shown in Table 6.

[0291] (G / D ratio)

[0292] The G / D ratio was evaluated using a laser Raman spectrophotometer (manufactured by Nihon Bunko, NRS-3100). Measurements were taken under conditions of an excitation laser wavelength of 532 nm, and the D-band (1330–1370 cm⁻¹) of the Raman spectra of each obtained sample (see Fig. 2) -1 ) and G-band (1560~1620cm -1 The G / D ratio was calculated from the ratio of peak intensities (IG / ID).

[0293] (Raman shift difference [PQ])

[0294] The difference in Raman shift (PQ) was evaluated using a laser Raman spectrophotometer (manufactured by Nihon Bunko, NRS-3100). Measurements were taken under conditions of an excitation laser wavelength of 532 nm, and the D-band (1330–1370 cm⁻¹) of the Raman spectra of each obtained sample -1 Raman shift at the peak top and G-band (1560~1620cm) -1 (PQ) was calculated from the difference in the Raman shift of the peak top of ).

[0295] [Table 5]

[0296]

[0297] [Table 6]

[0298]

[0299] [Example A19]

[0300] 1.1 parts of boron carbide (manufactured by Fujifilm Wako Junyaku Co., Ltd.), a boron source, and 1,000 parts of toluene, a solvent, were mixed in a mixer and then dispersed in a sand mill. After that, 98.9 parts of F#1 (natural graphite, manufactured by Nippon Kokuen Kogyo Co., Ltd.), a carbon source, were added and mixed in a mixer. After drying the solvent, compounding was performed in a particle compounding device, Mechanofusion (manufactured by Hosokawa Micron Co., Ltd.), to produce a precursor (28). Also, in Table 7, the same mixing method as that of the precursor (28) is indicated as treatment (6).

[0301] Next, a precursor (28) is filled into a graphite crucible and heat-treated at 2000°C for 1 hour under an argon atmosphere in a kiln to obtain a carbon material (28).

[0302] [Examples A20, A34]

[0303] Carbon materials (29) and (43) were produced in the same manner as Example A19, except that the raw materials and conditions shown in Table 7 were used.

[0304] [Examples A21, A22, A25–A30, A33, A35, A36]

[0305] Carbon materials (30), (31), (34) to (39), (42), (44), and (45) were produced in the same manner as Example A8, except that the raw materials and conditions shown in Table 7 were used.

[0306] [Example A23]

[0307] 97.5 parts of carbon source F#1 (natural graphite, manufactured by Nippon Kokuen Kogyo Co., Ltd.), 0.5 parts of boron source boron carbide (manufactured by Fujifilm Wako Junyaku Co., Ltd.), 2 parts of boric acid (manufactured by Fujifilm Wako Junyaku Co., Ltd.), 900 parts of solvent toluene, 100 parts of ethanol, and 0.1 parts of dispersant PVB (Esrec BL-10, manufactured by Sekisui Kagaku Kogyo Co., Ltd.) were dispersed using a Hysia mixer (L5M-A, manufactured by SILVERSON). After drying the solvent, compounding was performed in a particle compounding device Mechano Fusion (manufactured by Hosokawa Micron Co., Ltd.) to produce a precursor (32). In addition, in Table 7, the same mixing method as the precursor (32) is indicated as treatment (7).

[0308] Next, the precursor (32) is filled into a graphite crucible and heat-treated at 2000°C for 1 hour under an argon atmosphere in a kiln to obtain a carbon material (32).

[0309] [Example A24]

[0310] A carbon material (33) was produced in the same manner as Example A23, except that the raw materials and conditions shown in Table 7 were used.

[0311] [Example A31]

[0312] 0.2 parts of boron carbide (manufactured by Fujifilm Wako Junyaku Co., Ltd.), a boron source, and 1,000 parts of toluene, a solvent, were mixed in a mixer and then dispersed in a sand mill. After that, 99.8 parts of FB-150 (natural graphite, manufactured by Nippon Kokuen Kogyo Co., Ltd.), a carbon source, were added and dispersed using an ultrasonic homogenizer, and then the solvent was dried to produce a precursor (40). Also, in Table 7, the same mixing method as that of the precursor (40) is indicated as treatment (8).

[0313] Next, a precursor (40) is filled into a graphite crucible, and heat treatment is performed at 2400°C for 1 hour under an argon atmosphere in a kiln to obtain a carbon material (40).

[0314] [Example A32]

[0315] A carbon material (41) was produced in the same manner as Example A31, except that the raw materials and conditions shown in Table 7 were used.

[0316] For the carbon material described above, the <Evaluation of Carbon Material> and the evaluation of (G / D ratio) and (difference in Raman shift [PQ]) described above were performed. The results are shown in Table 8.

[0317] [Table 7]

[0318]

[0319] [Table 8]

[0320]

[0321] According to the results of Example A above, a carbon material in which the boron in the material is within the scope of the present invention exhibited excellent conductivity.

[0322] Manufacture of Binder Resin

[0323] [Preparation Example 1] Polyurethane resin solution

[0324] In a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, a dropping device, and a nitrogen inlet tube, 455.5 parts of a polyester polyol obtained from terephthalic acid, adipic acid, and 3-methyl-1,5-pentanediol (Curare Polyol P-2011 manufactured by Curare Inc., Mn=2,011), 16.5 parts of dimethylol butanoic acid, 105.2 parts of isophorone diisocyanate, and 140 parts of toluene were added, and the mixture was reacted at 90°C for 3 hours under a nitrogen atmosphere, and 360 parts of toluene were added thereto to obtain a urethane prepolymer solution having isocyanate groups.

[0325] Next, 969.5 parts of the obtained urethane prepolymer solution having isocyanate groups were added to a mixture of 19.9 parts isophoronediamine, 0.63 parts di-n-butylamine, 294.5 parts 2-propanol, and 335.5 parts toluene (the total equivalent of amino groups with respect to the free isocyanate groups at both ends of the urethane prepolymer is 0.98), reacted at 50°C for 3 hours, then reacted at 70°C for 2 hours, and diluted with 126 parts toluene and 54 parts 2-propanol to obtain a polyurethane resin solution having a weight average molecular weight of 61,000 and an acid value of 10 mgKOH / g.

[0326] The obtained polyurethane resin solution was diluted with toluene / methyl ethyl ketone / 2-propanol (mass ratio: 1 / 1 / 1) to obtain a polyurethane resin solution with a solid content of 20 mass%.

[0327] [Preparation Example 2] Polyamide resin solution

[0328] In a four-necked flask equipped with a stirrer, a reflux condenser, a nitrogen inlet tube, an inlet tube, and a thermometer, 156.2 parts of Prepol 1009 (hydrogenated dimer acid, manufactured by Croda Japan Co., Ltd.) as a polybasic acid compound, 5.5 parts of 5-hydroxyisophthalic acid, 146.4 parts of Priamine 1074 (manufactured by Croda Japan Co., Ltd.) as a polyamine compound, and 100 parts of ion-exchanged water were added, and the mixture was stirred until the exothermic temperature became constant. Once the temperature stabilized, the temperature was raised to 110°C, and after confirming the outflow of water, the temperature was raised to 120°C after 30 minutes. Subsequently, the dehydration reaction was continued while raising the temperature by 10°C every 30 minutes. After the temperature reached 230°C, the reaction was continued at that temperature for 3 hours, maintained under a vacuum of approximately 2 kPa for 1 hour, and then the temperature was lowered. Finally, by adding an antioxidant, a polyamide resin was obtained with a weight average molecular weight of 24,000, an acid value of 13.2 mgKOH / g, a hydroxyl group of 5.5 mgKOH / g, and a glass transition temperature of -32℃.

[0329] The obtained polyamide resin was diluted with toluene / 2-propanol (mass ratio: 2 / 1) to obtain a polyamide resin solution with a solid content of 20 mass%.

[0330] [Preparation Example 3] Polyester resin solution

[0331] Byron 200 (manufactured by Toyobo Co., Ltd., polyester resin) was diluted with toluene / methyl ethyl ketone (mass ratio: 1 / 1) to obtain a polyester resin solution with a solid content of 20 mass%.

[0332] In addition, the evaluation of Suji was performed as follows.

[0333] (Weight-average molecular weight (Mw))

[0334] The weight-average molecular weight was measured using the gel permeation chromatography (GPC) “HPC-8020” manufactured by Tosho Corporation. GPC is a liquid chromatography that separates and quantifies substances dissolved in a solvent (THF; tetrahydrofuran) based on differences in their molecular sizes. In the present invention, the measurement was performed by connecting two “LF-604” columns (manufactured by Showa Denko Co., Ltd.: rapid analysis GPC columns: 6 mm ID × 150 mm size) in series, under conditions of a flow rate of 0.6 ml / min and a column temperature of 40°C, and the determination of the weight-average molecular weight was performed by polystyrene conversion.

[0335] (Av)

[0336] About 1 g of the sample was accurately weighed into an orbicular conical flask, and 100 ml of a toluene / ethanol mixture (volume ratio: toluene / ethanol = 2 / 1) was added to dissolve it. Phenolphthalein reagent was added as an indicator and maintained for 30 seconds. Afterwards, the solution was titrated with a 0.1 N alcoholic potassium hydroxide solution until it turned pale pink, and the acid value was calculated using the following formula.

[0337] Acid value (mgKOH / g) = (5.611 × a × F) / S

[0338] step,

[0339] S: Sample amount (g)

[0340] a: Consumption of 0.1N alcoholic potassium hydroxide solution (ml)

[0341] F: Titer of 0.1N alcoholic potassium hydroxide solution

[0342] (Hydroxyl V)

[0343] The hydroxyl value is expressed as the amount of potassium hydroxide (mg) required to neutralize the acetic acid combined with the hydroxyl group when the hydroxyl group is acetylated, based on the amount of hydroxyl group contained in 1 g of the hydroxyl group-containing resin. The hydroxyl value is measured in accordance with JIS 0070, and in the present invention, it is calculated by considering the acid value as shown in the following formula.

[0344] Approximately 1 g of the sample was accurately weighed into an orbicular conical flask, and 100 ml of a toluene / ethanol mixture (volume ratio: toluene / ethanol = 2 / 1) was added to dissolve it. Additionally, 5 ml of an acetylating agent (a solution of 25 g of acetic anhydride dissolved in pyridine to a volume of 100 ml) was accurately added and stirred for approximately 1 hour. Phenolphthalein reagent was added as an indicator and stirred for 30 seconds. Afterward, the solution was titrated with a 0.1 N alcoholic potassium hydroxide solution until it turned pale pink, and the hydroxyl value was determined using the following formula.

[0345] Hydroxyl valence (mgKOH / g)=[{(ba)×F×28.05} / S]+D

[0346] step,

[0347] S: Sample amount (g)

[0348] a: Consumption of 0.1N alcoholic potassium hydroxide solution (ml)

[0349] b: Consumption of 0.1N alcoholic potassium hydroxide solution in the blank experiment (ml)

[0350] F: Titer of 0.1N alcoholic potassium hydroxide solution

[0351] D: Acid value (mgKOH / g)

[0352] (Glass transition temperature (Tg))

[0353] The glass transition temperature of the resin was measured by using a resin from which the solvent had been dried and removed, using "DSC-1" manufactured by Mettler Tread Co., Ltd., and increasing the temperature from -80 to 150°C at a rate of 2°C / min.

[0354] <Manufacture of conductive composition, conductive film>

[0355] [Example B1]

[0356] 88 parts of carbon material (2), 60 parts of polyurethane resin solution (12 parts resin solids) as binder resin, and 152 parts of toluene / methyl ethyl ketone / 2-propanol (mass ratio: 1 / 1 / 1) as solvent were put into a mixer and mixed, then put into a sand mill and dispersed to obtain a conductive composition (1).

[0357] Next, this conductive composition (1) was applied onto a PET film substrate with a thickness of 100 μm using a doctor blade and then dried in an oven. After that, a conductive film (1) was obtained by rolling it under conditions of a linear pressure of 300 kg / cm.

[0358] [Examples B2~B5, Comparative Examples B1, B2]

[0359] Conductive compositions (2) to (7) and conductive films (2) to (7) were obtained by the same method as in Example B1, except that the composition was changed to the formulation shown in Table 9-1.

[0360] [Example B6]

[0361] 5 parts of carbon material (12), 1 part of PVP (2) (polyvinylpyrrolidone, manufactured by Fujifilm Wako Junyaku Co., Ltd., K-30) as binder resin, and 94 parts of NMP as solvent were mixed in a mixer and then dispersed in a sand mill to obtain a conductive composition (8).

[0362] Next, the conductive composition (8) was applied onto a PET film substrate with a thickness of 100 μm using a doctor blade, and then dried in an oven to obtain a conductive film (8).

[0363] [Examples B7–B10, Comparative Examples B3–B5]

[0364] Conductive compositions (9) to (12), (17) to (19) and conductive films (9) to (12), (17) to (19) were obtained by the same method as Example B6 with the mixing composition ratios shown in Table 9-2.

[0365] [Example B11]

[0366] 3 parts of carbon material (13), 0.6 parts of polyvinyl alcohol (PVA) (manufactured by Kuraray, Kuraray Povall SD1000) as a binder resin, and 96.4 parts of ion-exchanged water as a solvent were mixed in a mixer and then dispersed in a sand mill to obtain a conductive composition (13).

[0367] Next, the conductive composition (13) was applied using a doctor blade onto a PET film substrate with a thickness of 100 μm, and then dried in an oven to obtain a conductive film (13).

[0368] [Examples B12–B14, Comparative Examples B6–B8]

[0369] Conductive compositions (14) to (16), (20) to (22) and conductive films (14) to (16), (20) to (22) were obtained by the same method as in Example B11 with the mixing composition ratios shown in Table 9-2.

[0370] [Example B15]

[0371] 57 parts of carbon material (29), 13 parts of CB (1) as a conductive aid, 150 parts of polyurethane resin solution as a binder resin (30 parts of resin solid content), and toluene / methyl ethyl ketone / 2-propanol (mass ratio: 1 / 1 / 1) as a solvent were mixed in a mixer so that the solid content in the composition was 30 mass%, and then dispersed in a sand mill to obtain a conductive composition (23).

[0372] Next, the conductive composition (23) was applied onto a PET film substrate with a thickness of 100 μm using a doctor blade, and then dried in an oven to obtain a conductive film (23).

[0373] [Examples B16–B37, B39, Comparative Examples B9–B13]

[0374] Conductive compositions (24) to (45), (47) to (52) and conductive films (24) to (45), (47) to (52) were obtained by the same method as in Example B15, with the mixing composition ratios shown in Tables 9-3 and 9-4.

[0375] [Example B38]

[0376] 56 parts of carbon material (41), 18 parts of CB (3) (acetylene black HS-100, manufactured by Denka Co.) as a conductive agent, and 300 parts of an aqueous solution (6 parts of resin solids) in which 2 mass% of water-soluble resin CMC (manufactured by Daicel Millise Co., Carboxymethylcellulose #1240) as a binder resin was dissolved, were mixed in a mixer, and then dispersed in a sand mill.

[0377] Next, 40 parts (20 parts resin solids) of water-based resin microparticles (polyacrylic emulsion W-168, manufactured by Toyochem Co., Ltd., solid content 50 mass%) were added as binder resin and mixed with a mixer to obtain a conductive composition (46).

[0378] Next, this conductive composition (46) was applied onto a PET film substrate with a thickness of 100 μm using a doctor blade, and then dried in an oven to obtain a conductive film (46).

[0379] Evaluation of Conductive Compositions and Conductive Films

[0380] The obtained conductive composition and conductive film were evaluated by the following methods. The evaluation results are shown in Tables 9-1 to 9-4.

[0381] (Evaluation of dispersion stability of conductive compositions)

[0382] Dispersion stability was evaluated from the change in liquid phase after storing the conductive composition at 25°C for 7 days. The change in liquid phase was determined from the ease of stirring when stirred with a spatula.

[0383] Judgment criteria

[0384] ○: No change in liquid state (Good)

[0385] △: Viscosity is increasing, but gelation is not occurring (possible)

[0386] ×: Gelling (defective)

[0387] (Potworkability Assessment)

[0388] The obtained conductive film was observed at 500x magnification using a video microscope VHX-900 (manufactured by Keyence), and coating non-uniformity and pinholes were judged according to the following criteria. Coating non-uniformity was judged by the shading of the film surface. Pinholes were judged by the presence or absence of uncoated defects within the film.

[0389] <<Unevenness in pottery>>

[0390] ○: No shading is observed on the film surface (Good)

[0391] △: There are 2 to 3 spots of shading on the film surface, but they are very minute regions (possible)

[0392] ×: Multiple shades are observed on the film surface, or one or more shade stripes with a length of 5mm or more are observed (defective)

[0393] Pinhole

[0394] ○: No pinholes found (Good)

[0395] △: There are 2 to 3 pinholes, but they are very minute (possible)

[0396] ×: Multiple pinholes are identified, or one or more pinholes with a diameter of 1 mm or more are identified (very poor)

[0397] (Volume resistivity of the membrane)

[0398] The volume resistivity of the conductive film was measured using the 4-terminal method with a Rollester GP (manufactured by Nitto Seiko Analytica Co., Ltd.) in accordance with JIS-K7194.

[0399] (Membrane durability)

[0400] The durability of the 0178 conductive film was evaluated by scratch hardness (pencil method) using a pencil with a hardness of HB in accordance with JIS K5600-5-4:1999.

[0401] ○: No plastic deformation or cohesive fracture occurs (Good)

[0402] △: Plastic deformation or cohesive fracture is occurring partially (possible)

[0403] ×: Plastic deformation and cohesive fracture are occurring (very poor)

[0404] [Table 9-1]

[0405]

[0406] [Table 9-2]

[0407]

[0408] [Table 9-3]

[0409]

[0410] [Table 9-4]

[0411]

[0412] According to the results of Example B above, a conductive composition using a boron-doped carbon material in which the boron in the material is within the scope of the present invention has excellent dispersion stability and coating properties, and a conductive film formed from the conductive composition has both high conductivity and durability.

[0413] In addition, by comparing Examples B1, B3 to B5, or Examples B7 and B8, it was found that differences in the boron content of carbon materials have a significant effect on the characteristics of the conductive composition or conductive film. Since there is a tendency for good dispersibility due to the boron content, the dispersion stability and coating properties were good. Furthermore, by comparing Examples B20, B22, B27, or B35 and B36, regarding the combined use of graphite with carbon black or carbon nanotubes, by using two or more different boron-doped carbon materials within the scope of the present invention, a conductive composition with good coating properties was obtained, and thus a uniform coating film without stains was obtained.

[0414] Therefore, these results suggest that factors other than the conductivity attributable to the carbon material are involved. Although the details are unclear at this stage, it is presumed that the conductive composition of the present invention exhibits excellent conductivity because the carbon material efficiently forms a conductive network within the film, as the boron-doped carbon material not only has excellent conductivity but also good dispersibility and dispersion stability, and also has good coating properties. Furthermore, it is presumed that the uniform network of the carbon material improves the packing properties between the carbon materials, enabling the formation of a dense film, which also leads to improved durability of the conductive film.

[0415] <Manufacture of Composite Ink for Positive Pole Use>

[0416] [Example C1]

[0417] A conductive composition (8) shown in Table 10 and NMP containing 8 mass% of PVDF (Solef #5130, manufactured by Solvey Co., Ltd.) were stirred so that the composition (mass ratio) of the carbon material, PVDF, and positive electrode active material in the conductive composition was 0.25 / 1.5 / 98.25. Then, the positive electrode active material NCM523 (manufactured by Nihon Kagaku Kogyo Co., Ltd., composition: LiNi0.5Co0.2Mn0.3O2) was added and stirred. Additionally, NMP was added and stirred so that the solid content of the positive electrode composite ink was 75 mass% to obtain the positive electrode composite ink (1). A rotating or orbiting mixer was used for all of the above stirring.

[0418] [Examples C2~C5, Comparative Examples C1~C3]

[0419] Positive electrode composite inks (2) to (8) were obtained in the same manner as Example C1, except that the conductive composition shown in Table 10 was changed.

[0420] Evaluation of Jeong Geuk-yong Composite Ink

[0421] (Volume resistivity of positive electrode composite layer)

[0422] A positive electrode composite ink was coated onto a PET substrate using an applicator so that the electrode coating amount was 20 mg / cm², and then dried in an electric oven at 120°C for 30 minutes to obtain a positive electrode. Afterward, the surface resistivity (Ω / □) of the film after drying was measured using a Rollester GP, MCP-T610 manufactured by Nitto Seiko Analytec. After measurement, the volume resistivity (Ω·cm) of the positive electrode film was obtained by multiplying by the thickness of the composite layer formed on the PET substrate. The thickness of the composite layer was determined by subtracting the thickness of the PET substrate from the average value of five points measured in the film using a film thickness gauge.

[0423] Judgment criteria

[0424] ◎: Volume resistivity (Ω·cm) of the positive electrode composite layer is less than 8 (excellent)

[0425] ○: Volume resistivity (Ω·cm) of the positive electrode composite layer is 8 or higher and less than 12 (good)

[0426] △: Volume resistivity (Ω·cm) of the positive electrode composite layer is 12 or more and less than 16 (possible)

[0427] ×: Volume resistivity (Ω·cm) of the positive electrode composite layer is 16 or higher (defective)

[0428] (Peeling strength of the positive electrode composite layer)

[0429] The positive electrode composite ink was coated onto an aluminum foil using an applicator so that the electrode coating amount was 20 mg / cm², and then dried in an oven at 120°C for 30 minutes. Afterward, two rectangular pieces measuring 90 mm × 20 mm were cut with the coating direction as the long axis. The peel strength was evaluated using a tensile testing machine and the 180-degree peel test method. Specifically, a double-sided tape measuring 100 mm × 30 mm was attached to a stainless steel plate, the fabricated composite layer was pressed against the other side of the double-sided tape, and peeled while pulling from bottom to top at a constant speed (50 mm / min); the average value of the stress at this time was taken as the peel strength.

[0430] Judgment criteria

[0431] ◎: Peel strength (N / cm) of the positive electrode composite layer is 0.3 or higher (excellent)

[0432] ○: Peel strength (N / cm) of the positive electrode composite layer is 0.25 or higher and less than 0.3 (Good)

[0433] △: Peel strength (N / cm) of the positive electrode composite layer is 0.2 or higher and less than 0.25 (possible)

[0434] ×: Peel strength (N / cm) of the positive electrode composite layer is less than 0.2 (poor)

[0435] Manufacture of Composite Ink for Negative Electrode

[0436] [Example C6]

[0437] A conductive composition (13) shown in Table 10 and an aqueous solution in which 2 mass% of CMC (manufactured by Daicel Finechem Co., Ltd., #1190) was dissolved were stirred such that the composition (mass ratio) of the carbon material, CMC, SBR, and negative electrode active material (graphite / silicon monoxide) in the conductive composition was 0.5 / 1 / 88 / 9 / 1.5. Then, silicon monoxide (manufactured by Osaka Titanium Technology Co., Ltd., SILICON MONOOXIDE, SiO 1.3C 5㎛) was added and stirred. Additionally, graphite (manufactured by Nippon Kokuen Kogyo Co., Ltd., CGB-20) was added and stirred. After that, SBR (manufactured by JSR Co., Ltd., TRD2001, dispersion with 48 mass% solid content) was added and stirred. Finally, ion-exchanged water was added and stirred so that the solid content of the negative electrode composite ink was 50 mass%, thereby obtaining the negative electrode composite ink (1). All of the above stirrings used a rotating orbiting mixer.

[0438] [Examples C7~C9], Comparative Examples C4~C6]

[0439] The negative electrode composite inks (2) to (7) were obtained in the same manner as Example C6, except that the conductive composition shown in Table 10 was changed.

[0440] Evaluation of Composite Ink for Negative Polarity

[0441] (Volume resistivity of negative electrode composite layer)

[0442] The volume resistivity (Ω·cm) of the negative electrode composite layer was measured by using a negative electrode composite ink and making it identical to the positive electrode composite layer except that the electrode coating amount was 8 mg / cm².

[0443] Judgment criteria

[0444] ◎: Volume resistivity (Ω·cm) of the negative electrode composite layer is less than 0.12 (Excellent)

[0445] ○: Volume resistivity (Ω·cm) of the negative electrode composite layer is 0.12 or higher and less than 0.15 (Good)

[0446] △: Volume resistivity (Ω·cm) of the negative electrode composite layer is 0.15 or higher and less than 0.25 (possible)

[0447] ×: Volume resistivity (Ω·cm) of the negative electrode composite layer is 0.25 or higher (defective)

[0448] (Peeling strength of the negative electrode composite layer)

[0449] The peel strength of the negative electrode composite layer was measured in the same way as the peel strength of the positive electrode composite layer, except that the negative electrode composite ink was coated on the copper foil using an applicator so that the electrode coating amount was 8 mg / cm².

[0450] Judgment criteria

[0451] ◎: Peel strength (N / cm) of the negative electrode composite layer is 0.5 or higher (excellent)

[0452] ○: Peel strength (N / cm) of the negative electrode composite layer is 0.4 or higher and less than 0.5 (Good)

[0453] △: Peel strength (N / cm) of the negative electrode composite layer is 0.3 or higher and less than 0.4 (possible)

[0454] ×: Peel strength (N / cm) of the negative electrode composite layer is less than 0.3 (poor)

[0455] Manufacture of Non-Aqueous Electrolyte Secondary Batteries

[0456] The standard negative electrode (A) and standard positive electrode (C) for evaluation were manufactured using the following method.

[0457] [Production of Standard Pole (A)]

[0458] Acetylene black (manufactured by Denka Corporation, Denka Black (registered trademark) HS-100), CMC (manufactured by Daicel Finechem Co., Ltd., Carboxymethylcellulose #1190), and water were added to a plastic container and stirred using a rotating and orbiting mixer. Additionally, graphite (manufactured by Nippon Kokuen Kogyo Co., Ltd., CGB-20) was added as a negative electrode active material and stirred using a rotating and orbiting mixer. Subsequently, SBR (manufactured by JSR Corporation, TRD2001, dispersion with 48 mass% solid content) was added and stirred using a rotating and orbiting mixer to obtain a standard negative electrode composite ink. The solid content of the standard negative electrode composite ink was set to 48 mass%. The solid content ratio of the negative electrode active material: conductive material: CMC: SBR in the standard negative electrode composite ink was set to 97:0.5:1:1.5.

[0459] Next, a standard negative electrode composite ink was applied using an applicator onto a 20 μm thick copper foil serving as a current collector, and then dried in an 80°C oven for 30 minutes to adjust the amount per unit area of ​​the electrode to 10 mg / cm². Additionally, a rolling treatment was performed using a roll press to produce a standard negative electrode (A) with a density of 1.6 g / cm³ of the negative electrode composite layer.

[0460] [Production of Standard Play (C)]

[0461] 93 parts of positive electrode active material (manufactured by BASF Toda Battery Materials Co., Ltd., HED (registered trademark) NCM-111 1100), 4 parts of acetylene black (manufactured by Denka Corporation, Denka Black (registered trademark) HS100), and 3 parts of PVDF (manufactured by Kureha Battery Materials Japan, Kureha KF Polymer W#1300) were added to a plastic container, and the mixture was mixed using a spatula until the powder became uniform. Then, 20.5 parts of NMP were added and stirred using a rotating / revolutionary mixer. Subsequently, the mixture in the plastic container was mixed using a spatula until it became uniform and stirred using the aforementioned rotating / revolutionary mixer. Then, 14.6 parts of NMP were added and stirred using the aforementioned rotating / revolutionary mixer. Finally, the mixture was stirred using a disperser to obtain a standard positive electrode composite ink. After that, the standard positive electrode composite ink was coated onto a 20 μm thick aluminum foil serving as a current collector using an applicator, and then dried in an oven at 120°C for 30 minutes to adjust the amount per unit area of ​​the electrode to 20 mg / cm². Additionally, a rolling treatment using a roll press was performed to produce a standard positive electrode (C) with a composite layer density of 3.1 g / cm³.

[0462] [Examples D1~D9, Comparative Examples D1~D6]

[0463] The positive and negative electrodes for evaluation were produced using the following method.

[0464] The positive electrode composite ink shown in Table 11 was coated onto a 20 μm thick aluminum foil serving as a current collector using an applicator, and then dried in an oven at 120°C for 30 minutes to adjust the electrode volume to 20 mg / cm². Additionally, a rolling treatment was performed using a roll press to produce a positive electrode with a positive electrode composite layer density of 3.1 g / cm³.

[0465] Meanwhile, the negative electrode composite ink shown in Table 11 was coated onto a copper foil with a thickness of 20 μm, which serves as a current collector, using an applicator, and then dried in an oven at 80°C for 30 minutes to adjust the electrode volume to 10 mg / cm². Additionally, a rolling treatment was performed using a roll press to produce a negative electrode with a density of 1.6 g / cm³ of the negative electrode composite layer.

[0466] The positive electrode and standard negative electrode (A) shown in Table 11, or the negative electrode and standard positive electrode (C) shown in Table 11, were punched into 50mm × 45mm and 45mm × 40mm, respectively. Then, the positive electrode, the separator (porous polypropylene film), and the standard negative electrode (A) were overlapped, and the standard positive electrode (C), the separator (porous polypropylene film), and the negative electrode were overlapped, each was inserted into an aluminum laminate bag, and dried in an electric oven at 70°C for 1 hour. Subsequently, 2mL of electrolyte was injected into a glove box filled with argon gas, and the aluminum laminate bag was sealed to produce non-aqueous electrolyte secondary batteries (1) to (15). The electrolyte is a non-aqueous electrolyte prepared by mixing ethylene carbonate, dimethyl carbonate, and diethyl carbonate in a ratio of 1:1:1 (volume ratio), adding VC (vinylene carbonate) as an additive at a ratio of 1:1:1 to 100 parts of the electrolyte, and then dissolving LiPF6 at a concentration of 1 M.

[0467] Evaluation of Non-Aqueous Electrolyte Secondary Batteries

[0468] The following evaluation was performed on the obtained non-aqueous electrolyte secondary battery. The evaluation results are shown in Table 11.

[0469] (Rate characteristics)

[0470] A non-aqueous electrolyte secondary battery was installed in a constant temperature room at 25°C, and charge / discharge measurements were performed using a charge / discharge device (manufactured by Hokuto Denko Co., Ltd., SM-8). After performing constant current constant voltage charging (cutoff current 1 mA (0.02 C)) at a charging current of 10 mA (0.2 C) with a charge termination voltage of 4.3 V, constant current discharge was performed at a discharge current of 10 mA (0.2 C) with a discharge termination voltage of 3 V. After repeating this operation three times, constant current constant voltage charging (cutoff current (1mA (0.02C)) was performed at a charging current of 10mA (0.2C) with a charging cutoff voltage of 4.3V, and constant current discharge was performed at discharge currents of 0.2C and 3C until the discharge cutoff voltage reached 3.0V, and the discharge capacity was calculated for each. The rate characteristic can be expressed by the following Equation 1 using the ratio of the 0.2C discharge capacity to the 3C discharge capacity.

[0471] (Equation 1)

[0472] Rate characteristic = 3C discharge capacity / 3rd 0.2C discharge capacity × 100(%)

[0473] Judgment criteria

[0474] ◎: Rate characteristics of 80% or higher (very excellent)

[0475] ○: Rate characteristics 70% or higher but less than 80% (Excellent)

[0476] ○△: Rate characteristics 60% or higher and less than 70% (Good)

[0477] △: Rate characteristic is 50% or more and less than 60% (possible)

[0478] ×: Rate characteristics less than 50% (defective)

[0479] (Cycle characteristics)

[0480] A non-aqueous electrolyte secondary battery was installed in a constant temperature room at 40°C, and charge / discharge measurements were performed using a charge / discharge device (manufactured by Hokuto Denko Co., Ltd., SM-8). After performing constant current constant voltage charging (cutoff current 2.5 mA (0.05 C)) at a charge current of 25 mA (0.5 C) with a charge cutoff voltage of 4.3 V, constant current discharge was performed at a discharge current of 25 mA (0.5 C) with a discharge cutoff voltage of 3 V. This operation was repeated 200 times. The cycle characteristics can be expressed by the following Equation 2 using the ratio of the 0.5 C discharge capacity at the 3rd cycle and the 0.5 C discharge capacity at the 200th cycle at 25°C.

[0481] (Equation 2)

[0482] Cycle Characteristics = 3rd 0.5C Discharge Capacity / 200th 0.5C Discharge Capacity × 100 (%)

[0483] Judgment criteria

[0484] ◎: Cycle characteristics of 80% or higher (very excellent)

[0485] ○: Cycle characteristics 70% or more but less than 80% (Excellent)

[0486] ○△: Cycle characteristics 60% or more and less than 70% (Good)

[0487] △: Cycle characteristics 60% or more and less than 70% (possible)

[0488] ×: Cycle characteristics less than 60% (poor)

[0489] [Table 10]

[0490]

[0491] [Table 11]

[0492]

[0493] According to the results of the above embodiments C and D, a lithium-ion secondary battery with excellent rate characteristics and cycle characteristics was obtained by using a conductive composition containing the carbon material of the present invention.

[0494] It is presumed that the conductive composition of the present invention exhibits good dispersibility and dispersion stability, and that the carbon nanotubes can efficiently form a conductive network within the electrode, resulting in good cycle characteristics. Furthermore, Comparative Examples D3 and D6 show poor cycle characteristics even though a conductive network is formed within the electrode. This is attributed to the fact that the carbon nanotubes containing boron within the scope of the present invention are more rigid, so the conductive network of the carbon nanotubes is maintained without collapsing during the repeated expansion and contraction of the active material during charging and discharging of the battery, thereby improving cycle characteristics. Meanwhile, when comparing Examples D1 to D3 or Examples D6 to D8, it was observed that differences in the boron content of the carbon nanotubes and the X / Y values ​​affect the battery characteristics (rate characteristics, cycle characteristics).

[0495] This application claims priority based on Japanese patent application No. 2020-067315 filed on April 3, 2020, and incorporates the entire disclosure thereof.

Claims

Claim 1 A carbon material having a carbon hexagonal lattice as a basic framework and doped with boron to substitute carbon atoms, wherein the boron content in the carbon material is 0.005 to 15 mol%, and when X (mol%) is the content of boron doped to substitute carbon atoms on the surface of the carbon material measured using X-ray photoelectron spectroscopy (XPS) and Y (mol%) is the content of boron in the entire carbon material measured using ICP emission spectroscopy, 0 <X / Y<0.8인 것을 특징으로 하는 탄소 재료. Claim 2 The carbon material according to claim 1, wherein the carbon material comprises at least one selected from the group consisting of graphite, graphene nanoplatelets, graphene, and carbon nanotubes. Claim 3 In paragraph 1 or 2, 0.01 <X / Y<0.4인 탄소 재료. Claim 4 A carbon material according to claim 1 or 2, wherein the ratio of peak intensity of the G band to the D band of the carbon material in a laser Raman spectrum (G / D ratio) is 1.7 or higher. Claim 5 A carbon material according to claim 1 or 2, wherein the average particle size of the carbon material is 0.5㎛ to 100㎛. Claim 6 A carbon material according to claim 1 or 2, wherein the average thickness of the carbon material is 150 nm to 50 µm. Claim 7 A conductive composition comprising a carbon material described in claim 1 or 2 and at least one of a binder resin or a solvent. Claim 8 In claim 7, the carbon material is a conductive composition comprising two or more other types of carbon materials. Claim 9 A conductive composition according to claim 7, further comprising a conductive aid. Claim 10 A conductive composition according to claim 7, further comprising an active material and used as a composite ink for forming a positive electrode or a negative electrode for a capacitor device. Claim 11 A conductive film formed from the conductive composition described in paragraph 7. Claim 12 A capacitor device having an electrode having a composite layer formed from the conductive composition described in claim 10.

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