WO2022239210A1 - Particle material composed of novel mxene nanosheets, dispersion containing said particle material, and method for producing said particle material - Google Patents

Particle material composed of novel mxene nanosheets, dispersion containing said particle material, and method for producing said particle material Download PDF

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WO2022239210A1
WO2022239210A1 PCT/JP2021/018297 JP2021018297W WO2022239210A1 WO 2022239210 A1 WO2022239210 A1 WO 2022239210A1 JP 2021018297 W JP2021018297 W JP 2021018297W WO 2022239210 A1 WO2022239210 A1 WO 2022239210A1
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mxene
particle material
mass
particulate material
particle
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PCT/JP2021/018297
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French (fr)
Japanese (ja)
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仁俊 佐藤
実 長田
雄己 新井
達也 前野
亘孝 冨田
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株式会社アドマテックス
国立大学法人東海国立大学機構
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Priority to PCT/JP2021/018297 priority Critical patent/WO2022239210A1/en
Priority to JP2023520702A priority patent/JPWO2022239210A1/ja
Publication of WO2022239210A1 publication Critical patent/WO2022239210A1/en

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    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G23/00—Compounds of titanium
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
    • H01M4/583—Carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • H01M4/587—Carbonaceous material, e.g. graphite-intercalation compounds or CFx for inserting or intercalating light metals
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present invention relates to a novel particle material composed of MXene nanosheets, a dispersion containing the particle material, and a method for producing the same.
  • MXene particle material a particle material made of an MXene layered compound obtained by removing Al from a MAX phase ceramic powder such as Ti 3 AlC 2 which is a layered compound by acid treatment
  • MXene particle material a particle material made of an MXene layered compound obtained by removing Al from a MAX phase ceramic powder such as Ti 3 AlC 2 which is a layered compound by acid treatment
  • MXene particle material a particle material made of an MXene layered compound obtained by removing Al from a MAX phase ceramic powder such as Ti 3 AlC 2 which is a layered compound by acid treatment
  • MXene particle material a layered compound by acid treatment
  • MAX phase ceramics are layered compounds, and the general formula is expressed as M n+1 AX n .
  • M is a transition metal (Ti, Sc, Cr, Zr, Nb, etc.)
  • A is an A group element
  • X is C or [C (1.0-x) N x (0 ⁇ x ⁇ 1.0)]
  • n is from 1 to 3.
  • the average thickness is 3.5 nm to 20 nm and the average size is 0.05 by bead mill treatment using 10 ⁇ m to 300 ⁇ m beads in ethanol or isopropanol (IPA). It is disclosed that MXene particulate material of ⁇ m to 0.3 ⁇ m is obtained without removing the unexfoliated portion by centrifugation.
  • MXene thin film When a dense thin film that is oriented and laminated along the C-axis is produced using the particle material of the present invention, electromagnetic waves will penetrate from the C-axis direction, and the electromagnetic waves will surely pass through MXene. It can be an electromagnetic wave shield thin film.
  • the MXene thin film may be formed on the thin film using metal plating or metal particle ink.
  • an MXene thin film may be formed on an organic film in which metal particles are dispersed.
  • the obtained nanosheet particle material exfoliated to the MXene single layer level is easily oxidized as it is, so it was desired to extend the life for industrial application.
  • the present invention has been completed in view of the above circumstances, and an object to be solved is to provide a novel particulate material made of MXene nanosheets, a dispersion containing the particulate material, and a method for producing the same.
  • the particle material of the present invention that solves the above problems is Ti 3 Al having an average thickness of 1.0 to 3.5 nm, an average size of 1.5 to 2.0 ⁇ m, and an interlayer distance of the (002) plane of 1.350 nm to 1.400 nm.
  • a particulate material having an MXene nanosheet material composed of a (C x N 1-x ) 2 , x 0.97-0.70, and a greater than 0.02.
  • the dispersion liquid of the present invention that solves the above problems is the above-mentioned particle material, the above-mentioned particle material is dispersed at 0.1% by mass to 0.4% by mass, and dimethyl sulfoxide (DMSO) is dispersed at 50% by mass or more. It is a dispersion liquid having a medium. It is more preferable to contain 100% by mass of dimethylsulfoxide (DMSO).
  • the method for producing a particulate material according to the present invention comprises a bead mill using beads of 10 ⁇ m to 300 ⁇ m, a dispersion medium containing 50% by mass or more of water, and a particle concentration of 10.0 mg/mL to 20.0 mg/ml.
  • a method for producing a particulate material composed of MXene nanosheets which includes a peeling step of exfoliating the MXene to form a peeled material by colliding microbeads between the layers of the mixture with the MXene dispersed in the dispersion medium in mL. is.
  • the dispersion medium preferably contains 80% by mass or more of water. It is more preferable to contain 100% by mass of water.
  • the particle material of the present invention provides a particle material made of MXene with a small thickness and a large size by having the above configuration. Furthermore, the dispersion liquid of the present invention can hold the particle material composed of MXene in a very stable state by having the above-described structure. With the above configuration, the method for producing a particulate material of the present invention can obtain a particulate material composed of MXene that is small in thickness and large in thickness.
  • FIG. 1 is AFM images of exfoliated products of Examples 1 and 2 and Comparative Example 1.
  • FIG. It is a SEM photograph of exfoliation of each example and a comparative example.
  • 2 shows XRD profiles of Examples 1 and 2 and Comparative Examples 1 and 3.
  • FIG. 4 is a spectrum showing the wavelength dependence of the transmittance of thin films obtained by spin-coating the exfoliated materials of Examples 1 and 2 and Comparative Example 1.
  • FIG. In (a) to (c), the number of spin coatings is 1, 2, 3, 4, and 5 from the top.
  • the particulate material, method for producing the same, and dispersion of the present invention will be described in detail below based on embodiments.
  • the particle material of the present embodiment is a particle material made of MXene having a small thickness and a large size, and is excellent in electrical properties such as conductivity.
  • the small and large thickness of the particulate material allows the formation of C-axis oriented, laminated, dense, and conductive thin films.
  • the obtained thin film can be applied as a conductive thin film, an electromagnetic wave shielding thin film, and the like.
  • the MXene thin film can also be formed on a substrate plated with metal, on a thin film made with metal particle ink, or on an organic film in which metal particles are dispersed.
  • the particulate material of the present embodiment is a particulate material made of MXene that is large and flakes for application to electromagnetic wave shielding thin films, conductive thin film materials, and the like.
  • MXene exfoliated particulate material is obtained by exfoliating MXene, which is a powdery layered compound.
  • the particulate material of the present embodiment is plate-like, leaf-like, flake-like, sheet-like, and the like. They are collectively called sheet-like.
  • the particle material of the present embodiment is MXene, which is a layered compound consisting of three layers of titanium and two layers of carbon, or a layered compound in which part of carbon is replaced with nitrogen.
  • a particulate material consisting of MXene represented by the composition formula Ti3Ala ( CxN1 -x ) 2 . where x 0.97-0.70 and a>0.02.
  • the upper limit of a is preferably 0.05. (hereinafter referred to as "MXene” as appropriate).
  • it can have O, OH, and halogen groups as surface functional groups.
  • the stacking direction of the layers of the layered compound is defined as "thickness”, and the direction perpendicular to the thickness is defined as “sheet spreading direction”, and the value measured in this direction is the particle material of the present embodiment. It's size.
  • the thickness of MXene can be measured by dropping MXene onto a hydrophilized Si wafer and performing AFM analysis.
  • the average thickness is 1.0 to 3.5 nm, preferably 1.50 to 2.00 nm.
  • the average thickness is calculated as the average of the values measured on 100 randomly selected particles.
  • the size of nanosheets can be measured by dropping MXene onto a hydrophilized Si wafer and observing it with SEM.
  • the average size of the nanosheet in the spreading direction is 1.5 to 2.0 ⁇ m, preferably 1.50 to 1.70 ⁇ m.
  • the interlayer distance of the (002) plane of MXene can be measured by X-ray diffraction analysis, and is preferably 1.350 nm to 1.400 nm. More preferably from 1.350 nm to 1.370 nm.
  • the zeta potential of MXene at pH 6 to pH 8 in water is preferably in the range of -29.0 mV to -34.0 mV.
  • the method for producing the particulate material of this embodiment has a peeling step and other necessary steps.
  • This exfoliated material suspension can be directly subjected to the mixing step, or can be subjected to the mixing step after removing the dispersion medium.
  • the method for obtaining layered MXene as a material is not particularly limited, but the following methods can be exemplified.
  • Ti 3 Al a (C x N 1-x ) 2 , x 0.97 to 0.70, a is more than 0.02.
  • the raw material to be subjected to the peeling step can employ those having the same composition as the material constituting the aforementioned particulate material.
  • the composition does not substantially change in the stripping process.
  • This particulate material is acid-treated to dissolve a portion of Al to form MXene, which is used to mix in a water-based solvent to form a mixture, followed by high-speed An exfoliate suspension in which sheet-like exfoliated material of MXene is suspended is obtained by the exfoliation step of rotating bead mill treatment.
  • the dispersion medium for the stripping step is not particularly limited except that it contains 50% by mass or more of water, but may contain alcohols such as methanol, ethanol, isopropanol, methyl ethyl ketone, acetone ketones, dimethylformamide, dimethyl sulfoxide, and the like. can.
  • alcohols such as methanol, ethanol, isopropanol, methyl ethyl ketone, acetone ketones, dimethylformamide, dimethyl sulfoxide, and the like.
  • lower limits for water content include 60% by mass, 70% by mass, 80% by mass, 90% by mass, and 100% by mass.
  • the concentration of MXene in the mixture for the stripping process is not particularly limited, but can be about 10.0 mg/mL to 20.0 mg/mL. Although there are no particular restrictions on the liquid properties of the mixed liquid, the pH can be adjusted to approximately 6.0 to 8.0.
  • the lower limit of the bead size can be 10 ⁇ m, 15 ⁇ m, 20 ⁇ m, 30 ⁇ m, 40 ⁇ m
  • the upper limit can be 300 ⁇ m, 200 ⁇ m, 100 ⁇ m.
  • it is 10 ⁇ m or more, it is easy to classify beads and slurry.
  • the use of beads of 300 ⁇ m or less allows delamination to proceed in preference to reducing the size of the particulate material. Any combination of these lower and upper limits can be adopted. If the size of the beads is in the proper range, the energy to be applied can be increased and the peeling can proceed preferentially.
  • the material of the beads is not particularly limited, but ceramics such as zirconia, alumina, and silicon nitride can be used. Partially stabilized zirconia, which has particularly high fracture toughness, is preferred.
  • Partially stabilized zirconia which has particularly high fracture toughness, is preferred.
  • Ball milling such as planetary ball milling with beads and balls greater than 300 ⁇ m, also favors exfoliation by reducing the size of the particulate material.
  • a peripheral speed of 6 m/sec to 12 m/sec can be adopted for the peripheral speed in the peeling process.
  • a peripheral speed of 8 m/sec to 10 m/sec is preferred. If it is 6 m/sec or more, the peeling efficiency is good, and if it is 12 m/sec or less, the application of excessive energy is suppressed, and the temperature rise of the obtained particle material can be suppressed, so that the surface of the obtained particle material is oxidized. Progression can be suppressed, and electrical resistance can be lowered.
  • a slurry feed rate of 100 mL/minute to 300 mL/minute can be adopted.
  • a slurry particle concentration of 20.0 mg/mL to 10.0 mg/mL can be adopted. More preferably 17.0 mg/mL to 10.0 mg/mL. More preferably 15.0 mg/mL to 10.0 mg/mL.
  • a condition of 20.0 mg/mL or less is preferable because peeling can proceed sufficiently, and classification by centrifugation or the like reduces the need to select a flaky particulate material. Furthermore, it becomes possible to keep the liquid particle size of the slurry small. When the amount is 10.0 mg/mL or more, the efficiency of peeling is improved.
  • the slurry temperature is preferably in the temperature range of 35°C or less. When the temperature is 35° C. or lower, surface oxidation can be suppressed, and the electrical resistance of the particulate material can be kept low.
  • 40% to 80% by volume can be used for the filling amount of beads. When it is 40% by volume or more, the efficiency of peeling is improved, and when it is 80% by volume or less, it becomes easy to classify beads and slurry. Whether or not the desired particle material containing many flaky particles is produced can be determined by observation with SEM, TEM, or the like. In particular, the thickness of the particulate material can be determined by AFM analysis. The particulate material obtained in the peeling step can be used after being classified by a method such as centrifugation, if necessary. Optimal conditions in the peeling process vary depending on the size of the apparatus, so these numerical values are not limited.
  • all the MXene becomes a stripped product by bead milling.
  • the peeling process is completed under the condition that all the MXene becomes the peeled material, it becomes possible to use the MXene that has not been peeled off without removing it.
  • MXene other than exfoliated matter it can be separated by centrifugation, filtration, or the like.
  • MXene in which part of the carbon sites are replaced with nitrogen, easily adsorbs OH groups in water, weakening the bond between layers. Therefore, the thickness and size of the resulting MXene can be controlled by varying the amount of nitrogen replaced.
  • x 0.85 to 0.70. 0.80 to 0.70 is more preferable. In both cases, a is over 0.02.
  • the amount of Al to be removed depends on the contact time with the acidic substance (acid aqueous solution, etc.) (the longer the time, the more removed), the concentration of the acidic substance (the higher the concentration, the more removed), It can be adjusted by changing the amount of acidic substance (the greater the absolute amount of acidic substance, the greater the amount that can be removed) and the contact temperature (the higher the temperature, the greater the amount removed).
  • the MAX-phase ceramic powder (A element is Al), which is a layered compound, is subjected to an acid treatment to remove part of the Al to form a layered compound having void layers that constitute the particle material.
  • an acidic substance in which hydrofluoric acid and hydrochloric acid are combined is employed as the acid for removing part of the Al layer.
  • a hydrofluoric acid salt KF, LiF, etc.
  • aqueous solutions of these acids are used as acidic substances.
  • the mixed concentration of hydrofluoric acid and hydrochloric acid formed when the fluoride salt is completely dissociated is not particularly limited.
  • the concentration of hydrofluoric acid the lower limit is about 1.7 mol/L, 2.0 mol/L, and 2.3 mol/L, and the upper limit is about 2.5 mol/L, 2.6 mol/L, and 2.7 mol/L. can.
  • the concentration of hydrochloric acid can be about 2.0 mol/L, 3.0 mol/L and 4.0 mol/L with lower limits and about 13.0 mol/L, 14.0 mol/L and 15.0 mol/L with upper limits. .
  • the mixing ratio (molar ratio) of hydrofluoric acid and hydrochloric acid formed when it is assumed that the fluoride salt is completely dissociated is not particularly limited, but the lower limit of hydrofluoric acid is 1:13, 1:12, 1:1: 11. About 1:5, 1:6 and 1:7 can be adopted as the upper limit.
  • the concentrations and mixing ratios of hydrofluoric acid and hydrochloric acid shown here can be used in arbitrary combinations.
  • the acid treatment temperature is preferably 10°C to 30°C. 10°C to 20°C is more preferred.
  • the resulting MXene nanosheet particle material was measured for zeta potential from pH 6 to pH 8 in water.
  • the zeta potential of pH 6 to pH 8 in water is all negative, and the acid treatment in water and the microbead mill treatment in water can adsorb hydrophilic functional groups such as OH and halogens, and the absolute value of the zeta potential is large. , means that more hydrophilic functional groups are adsorbed. If the absolute value of the zeta potential is too large, it will be pulverized into pieces by the applied physical force. The magnitude of the absolute value of the zeta potential is 29. It was found that thin and large MXene nanosheets were formed by adjusting the ratio from 0 to 34.0.
  • the amounts of Al, C, and N were calculated using atom % of Ti, Al, C, and N, with Ti being 3.
  • For chemical analysis weigh the sample in a platinum dish, add nitric acid + sulfuric acid + hydrofluoric acid, heat (about 120 ° C) to dissolve, and then heat at a high temperature (300 ° C) to mix nitric acid and hydrogen fluoride.
  • a sample solution sulfuric acid
  • the dispersion of this embodiment is obtained by dispersing the particulate material of this embodiment in a dispersion medium.
  • the particulate material dispersed in the dispersion liquid is MXene, which is easily oxidized, and normally cannot exist stably, but in this embodiment, it can stably exist for a long period of time. For this reason, it becomes possible to store the dispersion liquid for a long period of time, making it possible to dramatically expand the application fields of MXene.
  • MXene metal-oxidized sulfide
  • the dispersion medium contains dimethyl sulfoxide in an amount of 50% by mass or more, and particularly the lower limit of the content is 60% by mass, 70% by mass, 80% by mass, 90% by mass, 95% by mass, and 100% by mass. It is preferable that the content of dimethylsulfoxide is large, and it is particularly preferable that no dispersion medium other than dimethylsulfoxide is contained.
  • the composition of the dispersion medium that can be contained in addition to dimethylsulfoxide is not particularly limited, it is preferable that the dispersion medium contain hydrophilic properties. For example, ethanol and isopropyl alcohol can be included.
  • the content of dimethylsulfoxide can be 50% by mass or more, preferably 80% by mass or more, and preferably 90% by mass or more, based on the total mass of the dispersion medium. 100% by mass is more preferable.
  • it can contain no water.
  • the content of water can be 5% by mass or less, preferably 2% by mass or less, and 1% by mass or less, based on the total mass of the dispersion medium.
  • the concentration of particulate material in the dispersion of this embodiment is between 0.1% and 0.4% by weight.
  • Example 1 ⁇ Pretreatment process TiC powder (TI-30-10-0020, Raremetallic) 11.7g, TiN powder (TN-30-10-0020, Raremetallic) 0.6g, Ti powder (TIE07PB 3N, high purity Chemical) 4.9 g and Al powder (ALE15PB 3NG, Kojundo Chemical) 2.8 g were ball mill-mixed in isopropanol (IPA) for 12 hours, and the IPA was removed by an evaporator to obtain a uniformly mixed dry powder.
  • IPA isopropanol
  • the uniformly mixed dry powder was placed in an alumina crucible and fired under the conditions of 1450 ° C. for 2 h (heating rate 10 ° C./min) in an Ar stream to obtain Ti 3 Al (C) as MAX phase ceramics. 0.95 N 0.05 ) 2 was obtained.
  • the resulting Ti 3 Al(C 0.95 N 0.05 ) 2 was coarsely pulverized using a mortar and pestle, and then subjected to ball mill pulverization using 5 mm zirconia balls in IPA for 24 hours. Then, planetary ball mill pulverization (200 rpm, 15 minutes three times) using 0.5 mm zirconia balls was performed to obtain a suspension. IPA was removed from the suspension with an evaporator to obtain Ti 3 Al(C 0.95 N 0.05 ) 2 powder pulverized to about 3 ⁇ m.
  • An AFM image is shown in FIG. 100 exfoliated exfoliated products (nanosheets) were randomly sampled, and the average value of the thickness measured by AFM was obtained and shown in Table 1.
  • the result of SEM observation is shown in FIG. 100 exfoliated products were randomly selected, and the vertical (maximum diameter in the direction perpendicular to the thickness direction) and horizontal (direction perpendicular to the vertical and thickness directions) dimensions were measured from the SEM photograph, and the average value was calculated.
  • Table 1 shows the average value of the size of 100 exfoliated objects.
  • DMSO colloids The resulting DMSO suspension is centrifuged at 2400 G (3500 rpm) and the supernatant is collected (the supernatant is named DMSO colloids).
  • a piranha-treated glass plate (25 ⁇ 25 ⁇ 0.7 mm) was used as a substrate, and 20 ⁇ L of the solution was dropped and spin-coated at 4000 rpm for 1 minute to form a film.
  • FIG. 1 shows the results of measuring the surface electrical resistance after vacuum drying at 200°C for 24 hours.
  • Example 2 TiC powder (TI-30-10-0020, Rare Metallic) 9.2 g, TiN powder (TN-30-10-0020, Rare Metallic) 3.2 g, Ti powder (TIE07PB 3N, Kojundo Chemical) 4.9 g, Al A stripped product was prepared in the same manner as in Example 1, except that 2.8 g of powder (ALE15PB 3NG, Kojundo Chemical) was used as the starting material.
  • FIG. 1 shows AFM image
  • Table 1 shows average thickness and average size
  • Table 2 shows interlayer distance
  • Fig. 2 shows SEM image
  • Fig. 3 shows Ti3Al ( C0.75N0.25 ) 2 powder and Ti3Al0.02 obtained .
  • C 0.75 N 0.25 2 MXene XRD profile
  • FIG. 4 shows UV-vis results
  • Table 3 shows surface electrical resistance values.
  • Comparative example 1 Except that 12.3 g of TiC powder (TI-30-10-0020, Rare Metallic), 4.9 g of Ti powder (TIE07PB 3N, Kojundo Chemical), and 2.8 g of Al powder (ALE15PB 3NG, Kojundo Chemical) were used as starting materials.
  • Fig. 1 is AFM image
  • Table 1 is average thickness and average size
  • Table 2 is interlayer distance
  • Fig. 2 is SEM image
  • Fig. 3 is XRD profile of obtained Ti 3 AlC 2 powder and Ti 3 Al 0.02 C 2 MXene.
  • Table 3 shows the surface electrical resistance values.
  • Comparative Example 2 the particles were pulverized and did not form a sheet, and the average thickness and average size of the sheet could not be measured.
  • Comparative Example 3 in which only ethanol was used as the dispersion medium during the peeling process, the average thickness was large and the average size was small, and sufficient peeling could not be achieved. Furthermore, the interlayer distance of the (002) plane was also small. Using a dispersion medium containing water rather than using a dispersion medium that does not contain water in this way is better for obtaining thin and large nanosheets, and when peeling by a bead mill technique using microbeads. was found to be favorable.
  • MXene was exfoliated by ultrasonic irradiation, and a part of the exfoliated MXene nanosheets was collected by centrifugation.
  • a solvent is irradiated with ultrasonic waves, cavitation occurs, and due to the crushing of the cavitation, the layers that make up the layered compound are exfoliated by the mechanism of powder collision.
  • water which tends to cause cavitation, is used, the peeling progresses only partially.
  • pulverization takes precedence over exfoliation, and surface oxidation progresses, so MXene has not been studied at present.
  • the concentration of MXene particles of 10 mg/mL or more increases the efficiency of the stripping process, and the concentration of MXene particles of 20 mg/mL or less suppresses the remaining of the unstripped material and makes it a stripped material. made easier.

Abstract

The present invention addresses the problem to be solved of providing a particle material composed of novel MXene nanosheets, a dispersion containing the particle material, and a method for producing the particle material.　The particle material has an MXene nanosheet sheet having an average thickness of 1.0-3.5 nm and an average size of 1.5-2.0 μm, the MXene nanosheet material being configured from Ti3Ala(CxN1−x)2, for which the interlayer distance of the (002) plane is 1.350-1.400 nm, where x=0.97-0.70 and a exceeds 0.02, and the MXene nanosheet material being such that the zeta potential from a pH of 6 to a pH of 8 in water ranges from −29.0 mV to −34.0 mV. The dispersion has 0.1-0.4 mass% of the particle material dispersed therein, with dimethylsulfoxide being used as a dispersion medium. The method for producing the particle material has a detachment step for processing a mixture of a dispersion medium that includes 50 mass% or more of water and MXene dispersed in the dispersion medium at a particle concentration of 10-20 mg/mL in a bead mill using 10-300 μm beads, thereby detaching the MXene to form a detached product.

Description

新規なＭＸｅｎｅナノシートからなる粒子材料、その粒子材料を含有する分散液、及びその製造方法Particle material composed of novel MXene nanosheets, dispersion containing the particle material, and method for producing the same
　本発明は、新規なＭＸｅｎｅナノシートからなる粒子材料、その粒子材料を含有する分散液、及びその製造方法に関する。 The present invention relates to a novel particle material composed of MXene nanosheets, a dispersion containing the particle material, and a method for producing the same.
　従来から層状化合物であるＴｉ3ＡｌＣ2などのＭＡＸ相セラミックス粉末から酸処理によりＡｌを除去して得られるＭＸｅｎｅ層状化合物からなる粒子材料（本明細書では適宜「ＭＸｅｎｅ粒子材料」と称したり、「MXeneナノシート」と称したり、「層状化合物粒子材料」と称したり、単に「粒子材料」と称したりすることがある。）が知られている（特許文献１、２、３、４）。これらのＭＸｅｎｅ層状化合物は、Ａｌ層が除去された空隙層にＮａイオンやＬｉイオンが貯蔵／脱離可能であることから二次電池（蓄電池）やキャパシターの負極活物質材料、また導電性が優れていることから電磁波シールド薄膜や導電薄膜などへの応用が期待されている。 Conventionally, a particle material made of an MXene layered compound obtained by removing Al from a MAX phase ceramic powder such as Ti 3 AlC 2 which is a layered compound by acid treatment (in this specification, it is appropriately referred to as "MXene particle material" or " It is sometimes referred to as "MXene nanosheet", "layered compound particle material", or simply "particle material") ( Patent Documents 1, 2, 3, and 4). These MXene layered compounds can store and release Na ions and Li ions in the void layer from which the Al layer has been removed, so they are used as negative electrode active materials for secondary batteries (storage batteries) and capacitors, and also have excellent conductivity. Therefore, it is expected to be applied to electromagnetic wave shield thin films and conductive thin films.
　ＭＡＸ相セラミックスは層状化合物であり、一般式はＭn+1ＡＸnと表される。式中のＭは遷移金属（Ｔｉ、Ｓｃ、Ｃｒ、Ｚｒ、Ｎｂなど）、ＡはＡグループ元素、ＸはＣか、［Ｃ(1.0-x)Ｎx（０＜ｘ≦１．０）］、ｎは１から３、で構成されている。 MAX phase ceramics are layered compounds, and the general formula is expressed as M n+1 AX n . In the formula, M is a transition metal (Ti, Sc, Cr, Zr, Nb, etc.), A is an A group element, X is C or [C (1.0-x) N x (0<x≦1.0)] , n is from 1 to 3.
　その中、ＡをＡｌとした時、Ｍ－Ｘとの結合よりもＭ－Ａの結合が弱いため、酸処理で選択的にＡｌ層が除去される。本発明者らは、微小サイズのビーズを用いたビーズミルにより薄膜化して、ＭＸｅｎｅナノシートを調製する方法を提案している（特許文献５、６）。 Among them, when A is Al, the bond of MA is weaker than that of MX, so the Al layer is selectively removed by acid treatment. The present inventors have proposed a method of preparing MXene nanosheets by forming a thin film using a bead mill using micro-sized beads (Patent Documents 5 and 6).
　特許文献５、６の方法によれば、エタノール、又はイソプロパノール（IPA）中で10μm～300μmのビーズによるビーズミル処理で剥離することにより、厚みの平均値 3.5 nm～20 nm、大きさの平均値 0.05 μm～0.3μmであるMXene粒子材料が、遠心分離による未剥離部分を除去することなく得られることが開示されている。 According to the methods of Patent Documents 5 and 6, the average thickness is 3.5 nm to 20 nm and the average size is 0.05 by bead mill treatment using 10 μm to 300 μm beads in ethanol or isopropanol (IPA). It is disclosed that MXene particulate material of μm to 0.3 μm is obtained without removing the unexfoliated portion by centrifugation.
特開２０１６－６３１７１号公報Japanese Patent Application Laid-Open No. 2016-63171 特開２０１７－７６７３９号公報JP 2017-76739 A 米国特許出願公開第２０１７／０２９４５４６号明細書U.S. Patent Application Publication No. 2017/0294546 米国特許出願公開第２０１７／００８８４２９号明細書U.S. Patent Application Publication No. 2017/0088429 特許第６５６４５５３号公報Japanese Patent No. 6564553 特許第６５６４５５２号公報Japanese Patent No. 6564552
　ここで、特許文献５、６の方法でも十分に薄く且つ大きな粒子が得られてはいるものの、更に薄く（例えば単層レベルまで）剥離することや、更に大きなナノシート状の粒子材料を得ることを目指して本発明者らは更なる検討を行った。薄くて大きなナノシート状の粒子材料を基板に積層かつ稠密に並べれば極めて薄い導電薄膜や電磁波シールド薄膜を作製可能となる。例えば金属のメッキや金属粒子インクを用いた薄膜は粒状であるため、電磁波などの侵入に対しその隙間から電磁波が侵入してしまう。本発明の粒子材料で、C軸に配向、積層された、稠密な薄膜を作製すると、C軸方向から電磁波が侵入することになり、確実に電磁波がMXeneを通過することになるため、有効な電磁波シールド薄膜となりうる。この場合、金属のメッキあるいは金属粒子インクを用いた薄膜の上にMXene薄膜を形成させてもよい。あるいは金属粒子を分散させた有機物フィルムの上にMXene薄膜を形成させてもよい。 Here, although sufficiently thin and large particles are obtained by the methods of Patent Documents 5 and 6, it is difficult to exfoliate thinner (for example, to a monolayer level) or to obtain a larger nanosheet-like particle material. Aiming at this, the present inventors conducted further studies. If thin and large nanosheet-like particle materials are layered and arranged densely on a substrate, it is possible to fabricate extremely thin conductive thin films and electromagnetic wave shielding thin films. For example, since a thin film using metal plating or metal particle ink is granular, electromagnetic waves enter through the gaps when electromagnetic waves enter. When a dense thin film that is oriented and laminated along the C-axis is produced using the particle material of the present invention, electromagnetic waves will penetrate from the C-axis direction, and the electromagnetic waves will surely pass through MXene. It can be an electromagnetic wave shield thin film. In this case, the MXene thin film may be formed on the thin film using metal plating or metal particle ink. Alternatively, an MXene thin film may be formed on an organic film in which metal particles are dispersed.
　また、得られたMXene単層レベルまで剥離したナノシート粒子材料は、そのままでは酸化されやすいため、工業的に応用するためには長寿命化を図ることが望まれた。 In addition, the obtained nanosheet particle material exfoliated to the MXene single layer level is easily oxidized as it is, so it was desired to extend the life for industrial application.
　本発明は上記実情に鑑み完成したものであり、新規なＭＸｅｎｅナノシートからなる粒子材料、その粒子材料を含有する分散液、及びその製造方法を提供することを解決すべき課題とする。 The present invention has been completed in view of the above circumstances, and an object to be solved is to provide a novel particulate material made of MXene nanosheets, a dispersion containing the particulate material, and a method for producing the same.
　上記課題を解決する本発明の粒子材料は、平均厚さ1.0～3.5nm、平均大きさ1.5～2.0μmであり、（００２）面の層間距離が１．３５０nm～１.4０0nmであるTi3Ala（CxN1-x）2、x=0.97～0.70、aが0.02超、で構成されるMXeneナノシート材料を有する粒子材料である。 The particle material of the present invention that solves the above problems is Ti 3 Al having an average thickness of 1.0 to 3.5 nm, an average size of 1.5 to 2.0 μm, and an interlayer distance of the (002) plane of 1.350 nm to 1.400 nm. A particulate material having an MXene nanosheet material composed of a (C x N 1-x ) 2 , x=0.97-0.70, and a greater than 0.02.
　　上記課題を解決する本発明の分散液は、前述の粒子材料と、前記粒子材料を０．１質量％～０．４質量％で分散し、ジメチルスルホキシド（DMSO）を５０質量％以上含有する分散媒とを有する分散液である。ジメチルスルホキシド（DMSO）を１００質量％含有することがより好ましい。 The dispersion liquid of the present invention that solves the above problems is the above-mentioned particle material, the above-mentioned particle material is dispersed at 0.1% by mass to 0.4% by mass, and dimethyl sulfoxide (DMSO) is dispersed at 50% by mass or more. It is a dispersion liquid having a medium. It is more preferable to contain 100% by mass of dimethylsulfoxide (DMSO).
　上記課題を解決する本発明の粒子材料の製造方法は、１０μｍ～３００μｍのビーズを用いたビーズミルにおいて、水を５０質量％以上含有する分散媒と、粒子濃度１０．０mg/mＬ～２０．０mg/mＬで前記分散媒に分散されたＭＸｅｎｅとの混合物に対して層間に微小ビーズを衝突させることで、前記ＭＸｅｎｅを剥離して剥離物を形成する剥離工程を有するＭＸｅｎｅナノシートからなる粒子材料の製造方法である。特に前記分散媒は、水を８０質量％以上含有することが好ましい。水を１００質量％含有することがさらに好ましい。 The method for producing a particulate material according to the present invention, which solves the above problems, comprises a bead mill using beads of 10 μm to 300 μm, a dispersion medium containing 50% by mass or more of water, and a particle concentration of 10.0 mg/mL to 20.0 mg/ml. A method for producing a particulate material composed of MXene nanosheets, which includes a peeling step of exfoliating the MXene to form a peeled material by colliding microbeads between the layers of the mixture with the MXene dispersed in the dispersion medium in mL. is. In particular, the dispersion medium preferably contains 80% by mass or more of water. It is more preferable to contain 100% by mass of water.
　本発明の粒子材料は、上記構成を有することにより厚みが小さく大きなＭＸｅｎｅからなる粒子材料を提供する。更に、本発明の分散液は、上記構成を有することにより、非常に安定した状態でＭＸｅｎｅからなる粒子材料を保持することができる。本発明の粒子材料の製造方法は、上記構成を有することにより、厚みが小さく大きなＭＸｅｎｅからなる粒子材料を得ることができる。 The particle material of the present invention provides a particle material made of MXene with a small thickness and a large size by having the above configuration. Furthermore, the dispersion liquid of the present invention can hold the particle material composed of MXene in a very stable state by having the above-described structure. With the above configuration, the method for producing a particulate material of the present invention can obtain a particulate material composed of MXene that is small in thickness and large in thickness.
実施例１、２及び比較例１の剥離物のＡＦＭ像である。1 is AFM images of exfoliated products of Examples 1 and 2 and Comparative Example 1. FIG. 各実施例及び比較例の剥離物のＳＥＭ写真である。It is a SEM photograph of exfoliation of each example and a comparative example. 実施例１及び２、比較例１及び３のＸＲＤプロファイルである。2 shows XRD profiles of Examples 1 and 2 and Comparative Examples 1 and 3. FIG. 実施例１、２、比較例１の剥離物をスピンコートして形成して得られた薄膜の透過率の波長依存性を示したスペクトルである。なお、（ａ）～（ｃ）では上からスピンコートの数が１回、２回、３回、４回、５回である。4 is a spectrum showing the wavelength dependence of the transmittance of thin films obtained by spin-coating the exfoliated materials of Examples 1 and 2 and Comparative Example 1. FIG. In (a) to (c), the number of spin coatings is 1, 2, 3, 4, and 5 from the top.
　本発明の粒子材料及びその製造方法並びに分散液について実施形態に基づいて以下に詳細に説明を行う。本実施形態の粒子材料は、厚みが小さく大きさが大きいＭＸｅｎｅからなる粒子材料であり、導電性を示すなどの電気的特性に優れている。粒子材料の厚みが小さく、大きいことから、C軸配向、積層させた稠密で且つ導電性の薄膜を形成することができる。得られる薄膜は、導電薄膜、電磁波シールド薄膜などとして応用可能である。基板に金属のメッキをした上、あるいは金属粒子インクで作製した薄膜の上に、あるいは金属粒子を分散させた有機物フィルムの上に、MXene薄膜を形成させることもできる。
（粒子材料）
　本実施形態の粒子材料は、電磁波シールド薄膜や導電薄膜材料などへの応用のために大きくて薄片化されたＭＸｅｎｅからなる粒子材料である。ＭＸｅｎｅを薄片化した粒子材料は、粉末状層状化合物であるＭＸｅｎｅを剥離することにより得られる。 The particulate material, method for producing the same, and dispersion of the present invention will be described in detail below based on embodiments. The particle material of the present embodiment is a particle material made of MXene having a small thickness and a large size, and is excellent in electrical properties such as conductivity. The small and large thickness of the particulate material allows the formation of C-axis oriented, laminated, dense, and conductive thin films. The obtained thin film can be applied as a conductive thin film, an electromagnetic wave shielding thin film, and the like. The MXene thin film can also be formed on a substrate plated with metal, on a thin film made with metal particle ink, or on an organic film in which metal particles are dispersed.
(particle material)
The particulate material of the present embodiment is a particulate material made of MXene that is large and flakes for application to electromagnetic wave shielding thin films, conductive thin film materials, and the like. MXene exfoliated particulate material is obtained by exfoliating MXene, which is a powdery layered compound.
　本明細書において、あるパラメータに上限値と下限値をそれぞれ複数設定した場合には特に制限しない限りはそれらの上限値と下限値とを任意に組み合わせることができる。本実施形態の粒子材料は、板状、葉状、薄片状、シート状などである。総称してシート状と呼ぶ。 In this specification, when a plurality of upper limit values and lower limit values are set for a certain parameter, those upper limit values and lower limit values can be arbitrarily combined unless otherwise specified. The particulate material of the present embodiment is plate-like, leaf-like, flake-like, sheet-like, and the like. They are collectively called sheet-like.
　本実施形態の粒子材料は、チタン３層と炭素２層から成る層状化合物、あるいは炭素の一部を窒素に置き換えた層状化合物であるＭＸｅｎｅである。組成式Ti3Ala（CxN1-x）2により表されるＭＸｅｎｅからなる粒子材料である。ここで、x=0.97～0.70、aが0.02超である。ａの上限としては０．０５であることが好ましい。（以下　適宜「ＭＸｅｎｅ」と称する）。また、これらの元素以外にもＯ、ＯＨ、ハロゲン基を表面官能基として有することができる。 The particle material of the present embodiment is MXene, which is a layered compound consisting of three layers of titanium and two layers of carbon, or a layered compound in which part of carbon is replaced with nitrogen. A particulate material consisting of MXene represented by the composition formula Ti3Ala ( CxN1 -x ) 2 . where x=0.97-0.70 and a>0.02. The upper limit of a is preferably 0.05. (hereinafter referred to as "MXene" as appropriate). In addition to these elements, it can have O, OH, and halogen groups as surface functional groups.
　粒子材料を構成するＭＸｅｎｅは、層状化合物の層の積層方向を「厚み」とし、その厚みと直交する方向を「シートの拡がり方向」とし、この方向で測定した値が本実施形態の粒子材料の大きさである。 For MXene constituting the particulate material, the stacking direction of the layers of the layered compound is defined as "thickness", and the direction perpendicular to the thickness is defined as "sheet spreading direction", and the value measured in this direction is the particle material of the present embodiment. It's size.
　ＭＸｅｎｅの厚みは、親水化したSiウエハーにMXeneを滴下しAFM分析で測定できる。平均厚さが１．０～３．５ｎｍであり、特に１．５０～２．００ｎｍであることが好ましい。平均厚さは、ランダムに選択された１００個の粒子について測定した値の平均値として算出する。ナノシートの大きさは、親水化したSiウエハーにMXeneを滴下しSEM観察することにより測定できる。ナノシートの拡がり方向の平均の大きさが１．５～２．０μｍであり、特に１．５０～１．７０μｍであることが好ましい。厚みと直交する方向における最大値を「長辺」最小値を「短辺」とした場合に、ランダムに選択された１００個の粒子についてＳＥＭにより測定した、［（長辺＋短辺）／２］の平均値を拡がり方向の平均の大きさとする。 The thickness of MXene can be measured by dropping MXene onto a hydrophilized Si wafer and performing AFM analysis. The average thickness is 1.0 to 3.5 nm, preferably 1.50 to 2.00 nm. The average thickness is calculated as the average of the values measured on 100 randomly selected particles. The size of nanosheets can be measured by dropping MXene onto a hydrophilized Si wafer and observing it with SEM. The average size of the nanosheet in the spreading direction is 1.5 to 2.0 μm, preferably 1.50 to 1.70 μm. Measured by SEM for 100 randomly selected particles, where the maximum value in the direction orthogonal to the thickness is the “long side” and the minimum value is the “short side”, [(long side + short side) / 2 ] is taken as the average size in the spreading direction.
　ＭＸｅｎｅの（００２）面の層間距離はX線回折分析で測定することができ、１．３５０ｎｍ～１．４００ｎｍであることが好ましい。１．３５０ｎｍから１．３７０ｎｍであることがさらに好ましい。 The interlayer distance of the (002) plane of MXene can be measured by X-ray diffraction analysis, and is preferably 1.350 nm to 1.400 nm. More preferably from 1.350 nm to 1.370 nm.
　MXeneの水中ｐH６からｐH８におけるゼーター電位は、－２９．０ｍVから－３４．０ｍVの範囲であることが好ましい。
（粒子材料の製造方法）
　本実施形態の粒子材料の製造方法は、剥離工程とその他必要な工程とを有する。
・剥離工程
　剥離工程は、層状のTi3Ala（CxN1-x）2 、x=0.97～0.70、aが0.02超である　ＭＸｅｎｅに対して分散媒中において微小ビーズを層間に衝突させることにより剥離させてシート状の剥離物を得る工程である。得られた剥離物は、分散媒に懸濁した剥離物懸濁液になる。この剥離物懸濁液をそのまま混合工程に供したり、分散媒を除去して混合工程に供したりできる。材料となる層状のＭＸｅｎｅを得る方法としては特に限定しないが、以下の方法が例示できる。 The zeta potential of MXene at pH 6 to pH 8 in water is preferably in the range of -29.0 mV to -34.0 mV.
(Method for producing particle material)
The method for producing the particulate material of this embodiment has a peeling step and other necessary steps.
Exfoliation process In the exfoliation process, microbeads are collided between layers in a dispersion medium against MXene in which layered Ti 3 Al a (C x N 1-x ) 2 , x=0.97 to 0.70, and a is greater than 0.02. It is a step of obtaining a sheet-like exfoliated material by exfoliating the material. The resulting exfoliate becomes an exfoliate suspension suspended in the dispersion medium. This exfoliated material suspension can be directly subjected to the mixing step, or can be subjected to the mixing step after removing the dispersion medium. The method for obtaining layered MXene as a material is not particularly limited, but the following methods can be exemplified.
　Ti3Ala（CxN1-x）2 、x=0.97～0.70、aが0.02超である　ＭＸｅｎｅはＴｉ３層のＭＡＸ相セラミックス粉末からなる原料を酸処理してＡｌ層を一部溶解して得られる。ＭＸｅｎｅを製造する方法の一例を前処理工程として後述する。剥離工程に供される原料は、前述の粒子材料を構成する材料と同じ組成のものが採用できる。剥離工程では組成は概ね変化しない。 Ti 3 Al a (C x N 1-x ) 2 , x=0.97 to 0.70, a is more than 0.02. obtained by An example of a method for manufacturing MXene will be described later as a pretreatment step. The raw material to be subjected to the peeling step can employ those having the same composition as the material constituting the aforementioned particulate material. The composition does not substantially change in the stripping process.
　この粒子材料を酸処理によってＡｌの一部を溶解し、ＭＸｅｎｅとし、そのＭＸｅｎｅを用いて、水を主成分とする溶媒中に混合して混合物とした後、１０μｍから３００μｍのビーズを用いて高速回転を行うビーズミル処理する剥離工程によりシート状のＭＸｅｎｅの剥離物が懸濁する剥離物懸濁液が得られる。 This particulate material is acid-treated to dissolve a portion of Al to form MXene, which is used to mix in a water-based solvent to form a mixture, followed by high-speed An exfoliate suspension in which sheet-like exfoliated material of MXene is suspended is obtained by the exfoliation step of rotating bead mill treatment.
　剥離工程を行う分散媒は、水を５０質量％以上含有する以外は特に限定しないが、メタノール、エタノール、イソプロパノールなどのアルコール、メチルエチルケトン、アセトンなのケトン類、ジメチルホルムアミド、ジメチルスルホキシドなどを含有することもできる。特に水の含有量の下限値としては、６０質量％、７０質量％、８０質量％、９０質量％、１００質量％が挙げられる。 The dispersion medium for the stripping step is not particularly limited except that it contains 50% by mass or more of water, but may contain alcohols such as methanol, ethanol, isopropanol, methyl ethyl ketone, acetone ketones, dimethylformamide, dimethyl sulfoxide, and the like. can. In particular, lower limits for water content include 60% by mass, 70% by mass, 80% by mass, 90% by mass, and 100% by mass.
　剥離工程を行う混合物中のＭＸｅｎｅの濃度は特に限定しないが、１０．０ｍｇ／ｍＬ～２０．０ｍｇ／ｍＬ程度にすることができる。混合液の液性については特に限定しないが、ｐＨを６．０～８．０程度にすることができる。 The concentration of MXene in the mixture for the stripping process is not particularly limited, but can be about 10.0 mg/mL to 20.0 mg/mL. Although there are no particular restrictions on the liquid properties of the mixed liquid, the pH can be adjusted to approximately 6.0 to 8.0.
　剥離工程における具体的なビーズミル処理について説明する。遠心分離で微小なビーズとスラリー状の混合物を分級する機構を具備したビーズミルで剥離することが可能となる。ビーズミル処理により剥離した剥離物は、剥離前の混合物から遠心分離により随時分離でき、最終的には全てのＭＸｅｎｅを剥離物にすることもできる。 The specific bead mill processing in the peeling process will be explained. By centrifugal separation, a bead mill equipped with a mechanism for classifying fine beads and a slurry mixture can be used to separate them. The exfoliated material exfoliated by the bead mill treatment can be optionally separated from the mixture before exfoliation by centrifugation, and finally all MXene can be exfoliated.
　例えばビーズの大きさの下限は、１０μｍ、１５μｍ、２０μｍ、３０μｍ、４０μｍ、上限を３００μｍ、２００μｍ、１００μｍにすることができる。１０μｍ以上であるとビーズとスラリーの分級が容易である。３００μｍ以下のビーズを用いると粒子材料のサイズを小さくするよりも、剥離を優先して進行させることができる。これらの下限及び上限は任意に組み合わせて採用することができる。ビーズの大きさが適正な範囲であると付与するエネルギーが大きくでき、且つ、剥離を優先して進行できるため、５０μｍ～１００μｍのビーズを採用することが最も好ましい。 For example, the lower limit of the bead size can be 10 μm, 15 μm, 20 μm, 30 μm, 40 μm, and the upper limit can be 300 μm, 200 μm, 100 μm. When it is 10 µm or more, it is easy to classify beads and slurry. The use of beads of 300 μm or less allows delamination to proceed in preference to reducing the size of the particulate material. Any combination of these lower and upper limits can be adopted. If the size of the beads is in the proper range, the energy to be applied can be increased and the peeling can proceed preferentially.
　ビーズの材質は特に限定しないが、ジルコニア、アルミナ、窒化ケイ素などのセラミックスが採用できる。特に破壊靭性が大きい部分安定化ジルコニアが好ましい。一方、３００μｍ超のビーズを用いる微小サイズの隙間でビーズとスラリーを分級させる一般的に用いられるビーズミルによると、粒子材料のサイズを小さくすることが、剥離に優先して進行する。また、３００μｍ超のビーズやボールを用いた遊星ボールミルなどのボールミルによっても、粒子材料のサイズを小さくすることが剥離に優先する。結果として、一部しか剥離させることができず、一部の剥離したMXeneを分級採取する必要が生じ、産業に利用可能な剥離したMXene粒子材料を得ることができない。特に遊星ボールミルを用いると、表面酸化が進行しMXeneには適さず、検討もされていないのが実際である。一方、従来からMXeneの剥離手法として用いられている溶媒に超音波を照射する方法については、溶媒に超音波を照射するとキャビテーションが発生し、その圧壊により粉体どうしが衝突するメカニズムで層状化合物を構成する層の剥離が進行する。しかしながら、キャビテーションの発生が起きやすい水を用いたとしても、剥離が進行するのはほんの一部のみである。遠心分離による分級によって一部のMXeneナノシートの一部を採取する方法で作製されており、産業で利用できるレベルとは言えなかった。 The material of the beads is not particularly limited, but ceramics such as zirconia, alumina, and silicon nitride can be used. Partially stabilized zirconia, which has particularly high fracture toughness, is preferred. On the other hand, with commonly used bead mills that classify beads and slurries in micro-sized gaps using beads larger than 300 μm, size reduction of the particulate material progresses in preference to exfoliation. Ball milling, such as planetary ball milling with beads and balls greater than 300 μm, also favors exfoliation by reducing the size of the particulate material. As a result, only a part can be exfoliated, and some of the exfoliated MXenes need to be collected by classification, making it impossible to obtain an exfoliated MXene particle material that can be used industrially. In particular, when a planetary ball mill is used, surface oxidation progresses and it is not suitable for MXene, and in fact it has not been studied. On the other hand, in the conventional method of exfoliating MXene, in which ultrasonic waves are applied to a solvent, cavitation is generated when the solvent is irradiated with ultrasonic waves, and the collapsing of the cavitation causes the particles to collide with each other to separate the layered compound. Delamination of the constituent layers progresses. However, even if water, which is likely to cause cavitation, is used, the peeling progresses only partially. It was produced by a method of extracting a part of MXene nanosheets by classifying by centrifugation, and could not be said to be of a level that could be used in industry.
　剥離工程における周速は、６ｍ／ｓｅｃ～１２ｍ／ｓｅｃの周速が採用できる。８ｍ／ｓｅｃ～１０ｍ／ｓｅｃの周速が好ましい。６ｍ／ｓｅｃ以上であると剥離効率が良く、１２ｍ／ｓｅｃ以下であると付与する過大なエネルギー付与が抑制され、得られる粒子材料の温度上昇が抑制できるため、得られる粒子材料の表面における酸化の進行が抑制でき、電気抵抗を低くできる。スラリー送り速度は１００ｍＬ／分から３００ｍＬ／分が採用できる。スラリー粒子濃度は２０．０ｍｇ／ｍＬ～１０．０ｍｇ／ｍＬが採用できる。１７．０ｍｇ／ｍＬ～１０．０ｍｇ／ｍＬとするとより好ましい。１５．０ｍｇ／ｍＬ～１０．０ｍｇ／ｍＬとすると更に好ましい。 A peripheral speed of 6 m/sec to 12 m/sec can be adopted for the peripheral speed in the peeling process. A peripheral speed of 8 m/sec to 10 m/sec is preferred. If it is 6 m/sec or more, the peeling efficiency is good, and if it is 12 m/sec or less, the application of excessive energy is suppressed, and the temperature rise of the obtained particle material can be suppressed, so that the surface of the obtained particle material is oxidized. Progression can be suppressed, and electrical resistance can be lowered. A slurry feed rate of 100 mL/minute to 300 mL/minute can be adopted. A slurry particle concentration of 20.0 mg/mL to 10.0 mg/mL can be adopted. More preferably 17.0 mg/mL to 10.0 mg/mL. More preferably 15.0 mg/mL to 10.0 mg/mL.
　２０．０ｍｇ／ｍＬ以下の条件によると剥離が充分に進行でき、遠心分離などで分級することにより薄片状の粒子材料を選択する必要が低くなるため好ましい。さらに、スラリーの液中粒子径を小さく保つことが可能になる。１０．０ｍｇ／ｍＬ以上にすると剥離の効率が良くなる。 A condition of 20.0 mg/mL or less is preferable because peeling can proceed sufficiently, and classification by centrifugation or the like reduces the need to select a flaky particulate material. Furthermore, it becomes possible to keep the liquid particle size of the slurry small. When the amount is 10.0 mg/mL or more, the efficiency of peeling is improved.
　スラリー温度は３５℃以下の温度範囲が好ましい。３５℃以下にすると表面酸化が抑制でき、粒子材料の電気抵抗を低く保つことができる。 The slurry temperature is preferably in the temperature range of 35°C or less. When the temperature is 35° C. or lower, surface oxidation can be suppressed, and the electrical resistance of the particulate material can be kept low.
　ビーズの充填量は４０体積％～８０体積％が採用できる。４０体積％以上にすると剥離の効率が良くなり、８０体積％以下にするとビーズとスラリーの分級が容易となる。目的の薄片状の粒子を多く含む粒子材料が製造されたかどうかは、ＳＥＭ、ＴＥＭなどの観察によって判断できる。特に粒子材料の厚みについてはＡＦＭ分析することによって判断できる。剥離工程で得られた粒子材料は、必要に応じて遠心分離などの方法によって分級して使用することも可能である。剥離工程における最適な条件については、装置の大きさによって変化するので、これらの数値は限定されるものではない。 40% to 80% by volume can be used for the filling amount of beads. When it is 40% by volume or more, the efficiency of peeling is improved, and when it is 80% by volume or less, it becomes easy to classify beads and slurry. Whether or not the desired particle material containing many flaky particles is produced can be determined by observation with SEM, TEM, or the like. In particular, the thickness of the particulate material can be determined by AFM analysis. The particulate material obtained in the peeling step can be used after being classified by a method such as centrifugation, if necessary. Optimal conditions in the peeling process vary depending on the size of the apparatus, so these numerical values are not limited.
　ビーズミル処理によりＭＸｅｎｅが全て剥離物になるようにすることが好ましい。ＭＸｅｎｅが全て剥離物になる条件で剥離工程を完了すると、剥離していないＭＸｅｎｅを除去することなくそのまま用いることが可能になる。剥離物以外のＭＸｅｎｅを除去する場合には、遠心分離、濾過などにより分離することができる。 It is preferable that all the MXene becomes a stripped product by bead milling. When the peeling process is completed under the condition that all the MXene becomes the peeled material, it becomes possible to use the MXene that has not been peeled off without removing it. When removing MXene other than exfoliated matter, it can be separated by centrifugation, filtration, or the like.
　炭素サイトの一部を窒素に置き換えたMXene  は水中でOH基が吸着しやすくなり層間の結合力が弱まる。そのため置き換える窒素量を変えることにより、得られるMXeneの厚さと大きさを制御できる。Ti3Ala（CxN1-x）2 、x=0.97～0.70、aが０．０２超とすることにより、薄くて大きなナノシートが得られる。Xについて、0.8５～0.70とすることがさらに好ましい。0.8０から0.70とするとさらに好ましい。いずれもaは０．０２超である。 MXene, in which part of the carbon sites are replaced with nitrogen, easily adsorbs OH groups in water, weakening the bond between layers. Therefore, the thickness and size of the resulting MXene can be controlled by varying the amount of nitrogen replaced. By setting Ti 3 Al a (C x N 1-x ) 2 , x=0.97 to 0.70, and a greater than 0.02, thin and large nanosheets can be obtained. More preferably, X is 0.85 to 0.70. 0.80 to 0.70 is more preferable. In both cases, a is over 0.02.
　前処理工程に供する原料は、Ti3Ala（CxN1-x）2 、x=0.97～0.70、aが１．００で表される組成を有するＭＡＸ相セラミックス粉末である。さらに、Ａｌを除去する量は酸性物質により酸処理されて製造されるＭＡＸ相セラミックス粉末中のＡｌの量（ｘに相当）が０．０２超になる程度に残存するように調節する。なお、Ａｌを全部除去することも可能であり、その場合にはＡｌを除去する以上にまで酸処理を進めないことが好ましい。 The raw material to be subjected to the pretreatment step is MAX phase ceramic powder having a composition represented by Ti 3 Al a (C x N 1-x ) 2 , x=0.97 to 0.70, and a=1.00. Furthermore, the amount of Al to be removed is adjusted so that the amount of Al (corresponding to x) in the MAX phase ceramic powder produced by acid treatment with an acidic substance remains at a level exceeding 0.02. In addition, it is possible to remove all the Al, and in that case, it is preferable not to proceed the acid treatment beyond the removal of the Al.
　除去されるＡｌの量は、酸性物質（酸水溶液など）と接触する時間（長くすると除去される量が増加する）、酸性物質の濃度（濃度が高い方が除去される量が増加する）、酸性物質の量（酸性物質の絶対量が多い方が除去され得る量を多くできる）、接触させる温度（温度が高い方が除去される量が増加する）を変化させることで調節できる。 The amount of Al to be removed depends on the contact time with the acidic substance (acid aqueous solution, etc.) (the longer the time, the more removed), the concentration of the acidic substance (the higher the concentration, the more removed), It can be adjusted by changing the amount of acidic substance (the greater the absolute amount of acidic substance, the greater the amount that can be removed) and the contact temperature (the higher the temperature, the greater the amount removed).
　層状化合物であるＭＡＸ相セラミックス粉末（Ａ元素がＡｌ）に対して、酸処理を行うことによりＡｌの一部を除去して粒子材料を構成する空隙層を有する層状化合物とする。Ａｌ層の一部を除去するための酸としてはフッ酸と塩酸との組み合わせた酸性物質を採用する。フッ酸と塩酸との組み合わせを実現するためにはフッ酸の塩（ＫＦ、ＬｉＦなど）と塩酸とを混合してフッ酸と塩酸との混合物を得ることが好ましい。 The MAX-phase ceramic powder (A element is Al), which is a layered compound, is subjected to an acid treatment to remove part of the Al to form a layered compound having void layers that constitute the particle material. As the acid for removing part of the Al layer, an acidic substance in which hydrofluoric acid and hydrochloric acid are combined is employed. In order to achieve a combination of hydrofluoric acid and hydrochloric acid, it is preferable to mix a hydrofluoric acid salt (KF, LiF, etc.) with hydrochloric acid to obtain a mixture of hydrofluoric acid and hydrochloric acid.
　特に酸性物質としてはこれらの酸の水溶液を採用する。フッ化塩が完全に解離したと仮定した時に形成されるフッ酸と塩酸との混合濃度としては特に限定しない。フッ酸の濃度としては下限が１．７ｍｏｌ／Ｌ、２．０ｍｏｌ／Ｌ、２．３ｍｏｌ／Ｌ、上限が２．５ｍｏｌ／Ｌ、２．６ｍｏｌ／Ｌ、２．７ｍｏｌ／Ｌ程度にすることができる。塩酸の濃度としては下限が２．０ｍｏｌ／Ｌ、３．０ｍｏｌ／Ｌ、４．０ｍｏｌ／Ｌ、上限が１３．０ｍｏｌ／Ｌ、１４．０ｍｏｌ／Ｌ、１５．０ｍｏｌ／Ｌ程度にすることができる。 In particular, aqueous solutions of these acids are used as acidic substances. The mixed concentration of hydrofluoric acid and hydrochloric acid formed when the fluoride salt is completely dissociated is not particularly limited. As for the concentration of hydrofluoric acid, the lower limit is about 1.7 mol/L, 2.0 mol/L, and 2.3 mol/L, and the upper limit is about 2.5 mol/L, 2.6 mol/L, and 2.7 mol/L. can. The concentration of hydrochloric acid can be about 2.0 mol/L, 3.0 mol/L and 4.0 mol/L with lower limits and about 13.0 mol/L, 14.0 mol/L and 15.0 mol/L with upper limits. .
　フッ化塩が完全に解離したと仮定した時に形成されるフッ酸と塩酸との混合比（モル比）についても特に限定しないが、フッ酸の下限として、１：１３、１：１２、１：１１、上限として１：５、１：６、１：７程度を採用することができる。ここで示したフッ酸及び塩酸濃度、混合比についてはそれぞれ任意に組み合わせて採用することができる。酸処理温度については、１０℃から３０℃が好ましい。１０℃から２０℃がさらに好ましい。 The mixing ratio (molar ratio) of hydrofluoric acid and hydrochloric acid formed when it is assumed that the fluoride salt is completely dissociated is not particularly limited, but the lower limit of hydrofluoric acid is 1:13, 1:12, 1:1: 11. About 1:5, 1:6 and 1:7 can be adopted as the upper limit. The concentrations and mixing ratios of hydrofluoric acid and hydrochloric acid shown here can be used in arbitrary combinations. The acid treatment temperature is preferably 10°C to 30°C. 10°C to 20°C is more preferred.
　得られたMXeneナノシート粒子材料について、水中ｐH６からｐH８のゼーター電位を測定した。Ti3Ala（CxN1-x）2 において、X=０．９７で－２９．０ｍV、X=０．９５で－３１．５ｍV、X=0.90で－３２．１ｍV、X=0.85で－３２．４ｍV、X=0.75で－３３．１ｍV、X=0.70でー３４．０ｍVであった。一方、X=1.00でー２８．９ｍV、X=０．６５でー３４．５ｍVであった。水中ｐH６からｐH８のゼーター電位は全てマイナスであり、水中における酸処理、及び水中で微小サイズのビーズミル処理で「OHやハロゲンなどの親水性官能基が吸着し、ゼーター電位の絶対値が大きいことは、より多くの親水性官能基が吸着したことを意味する。あまりにゼーター電位の絶対値が大きくなると付与する物理的作用力で粉々に粉砕してしまう。ゼーター電位の絶対値の大きさを２９．０から３４．０とすることにより薄くて大きなMXeneナノシートが形成されることが分かった。 The resulting MXene nanosheet particle material was measured for zeta potential from pH 6 to pH 8 in water. In Ti 3 Al a (C x N 1-x ) 2 , −29.0 mV at X=0.97, −31.5 mV at X=0.95, −32.1 mV at X=0.90, and -32.4 mV, -33.1 mV at X=0.75, and -34.0 mV at X=0.70. On the other hand, it was -28.9 mV at X=1.00 and -34.5 mV at X=0.65. The zeta potential of pH 6 to pH 8 in water is all negative, and the acid treatment in water and the microbead mill treatment in water can adsorb hydrophilic functional groups such as OH and halogens, and the absolute value of the zeta potential is large. , means that more hydrophilic functional groups are adsorbed.If the absolute value of the zeta potential is too large, it will be pulverized into pieces by the applied physical force.The magnitude of the absolute value of the zeta potential is 29. It was found that thin and large MXene nanosheets were formed by adjusting the ratio from 0 to 34.0.
　MXeneナノシートの化学組成については、Ti、Al、C、Nのaｔom％を用いて、Tiを３とした時のAl、C、N量を算出した。化学分析は、試料を白金皿にはかりとり、硝酸＋硫酸＋フッ化水素酸を加えて、加熱（１２０℃程度）して溶解後、さらに高温（３００℃）で加熱して硝酸とフッ化水素酸を飛ばして試料溶液（硫酸）を作製し、作製した試料溶液を適宜希釈してICPで定量分析を行った。

（分散液）
　本実施形態の分散液は、本実施形態の粒子材料を分散媒中に分散させたものである。分散液中に分散された粒子材料は、酸化されやすいＭＸｅｎｅであり、通常は安定的に存在できないが、本実施形態では長期間安定して存在できる。そのために分散液の状態で長期間保存することが可能になり、ＭＸｅｎｅの応用分野を飛躍的に広げることが可能になる。この分散液を適正な基材上に塗布して乾燥することで、基材上にＭＸｅｎｅからなる導電薄膜、及び電磁波シールド薄膜を形成することが可能になる。その他、ＭＸｅｎｅを利用する場合に応用することが可能である。 Regarding the chemical composition of MXene nanosheets, the amounts of Al, C, and N were calculated using atom % of Ti, Al, C, and N, with Ti being 3. For chemical analysis, weigh the sample in a platinum dish, add nitric acid + sulfuric acid + hydrofluoric acid, heat (about 120 ° C) to dissolve, and then heat at a high temperature (300 ° C) to mix nitric acid and hydrogen fluoride. A sample solution (sulfuric acid) was prepared by removing the acid, and the prepared sample solution was appropriately diluted and quantitatively analyzed by ICP.

(dispersion liquid)
The dispersion of this embodiment is obtained by dispersing the particulate material of this embodiment in a dispersion medium. The particulate material dispersed in the dispersion liquid is MXene, which is easily oxidized, and normally cannot exist stably, but in this embodiment, it can stably exist for a long period of time. For this reason, it becomes possible to store the dispersion liquid for a long period of time, making it possible to dramatically expand the application fields of MXene. By coating this dispersion on an appropriate substrate and drying it, it becomes possible to form a conductive thin film and an electromagnetic wave shielding thin film made of MXene on the substrate. In addition, it is possible to apply when using MXene.
　分散媒としてはジメチルスルホキシドを５０質量％以上含有するものであり、特に含有量の下限値としては、６０質量％、７０質量％、８０質量％、９０質量％、９５質量％、１００質量％が挙げられ、ジメチルスルホキシドの含有量が多い方が好ましく、特にジメチルスルホキシド以外の分散媒を含有しないことが好ましい。ジメチルスルホキシド以外に含有可能な分散媒の組成としては、特に限定しないが、親水性の性質をもつものが含有されていることが好ましい。例えばエタノール、及びイソプロピルアルコールを含有することができる。ジメチルスルホキシドの含有量は分散媒全体の質量を基準として５０質量％以上にすることができ、８０質量％以上、９０質量％以上にすることが好ましい。１００質量％とすることがさらに好ましい。例えば水を含有しないことができる。水の含有量は分散媒全体の質量を基準として５質量％以下にすることができ、２質量％以下、１質量％以下にすることが好ましい。水が共存するとMXeneナノシート粒子材料の表面酸化が進行し導電性が劣化する。本実施形態の分散液中の粒子材料の濃度は、を０．１質量％～０．４質量％である。 The dispersion medium contains dimethyl sulfoxide in an amount of 50% by mass or more, and particularly the lower limit of the content is 60% by mass, 70% by mass, 80% by mass, 90% by mass, 95% by mass, and 100% by mass. It is preferable that the content of dimethylsulfoxide is large, and it is particularly preferable that no dispersion medium other than dimethylsulfoxide is contained. Although the composition of the dispersion medium that can be contained in addition to dimethylsulfoxide is not particularly limited, it is preferable that the dispersion medium contain hydrophilic properties. For example, ethanol and isopropyl alcohol can be included. The content of dimethylsulfoxide can be 50% by mass or more, preferably 80% by mass or more, and preferably 90% by mass or more, based on the total mass of the dispersion medium. 100% by mass is more preferable. For example, it can contain no water. The content of water can be 5% by mass or less, preferably 2% by mass or less, and 1% by mass or less, based on the total mass of the dispersion medium. When water coexists, surface oxidation of the MXene nanosheet particle material progresses and the conductivity deteriorates. The concentration of particulate material in the dispersion of this embodiment is between 0.1% and 0.4% by weight.
　本発明の粒子材料及びその製造方法、並びに分散液について以下実施例に基づき詳細に説明を行う。
（実施例１）
・前処理工程
　ＴｉＣ粉末（ＴＩ－３０－１０－００２０、レアメタリック社）１１．７ｇ、ＴｉＮ粉末（ＴＮ－３０－１０－００２０、レアメタリック社）０．６ｇ、Ｔｉ粉末（ＴＩＥ０７ＰＢ　３Ｎ、高純度化学）４．９ｇ、Ａｌ粉末（ＡＬＥ１５ＰＢ　３ＮＧ、高純度化学）２．８ｇをイソプロパノール（ＩＰＡ）中で１２時間　ボールミル混合し、エバポレータでＩＰＡを除去して均一混合された乾燥粉末を得た。 The particulate material, method for producing the same, and dispersion liquid of the present invention will be described in detail below based on examples.
(Example 1)
・Pretreatment process TiC powder (TI-30-10-0020, Raremetallic) 11.7g, TiN powder (TN-30-10-0020, Raremetallic) 0.6g, Ti powder (TIE07PB 3N, high purity Chemical) 4.9 g and Al powder (ALE15PB 3NG, Kojundo Chemical) 2.8 g were ball mill-mixed in isopropanol (IPA) for 12 hours, and the IPA was removed by an evaporator to obtain a uniformly mixed dry powder.
　黒鉛抵抗炉を用いてＡｒ気流中１４５０℃、２ｈ（昇温速度１０℃／分）の条件で、均一混合された乾燥粉末をアルミナるつぼに入れて焼成しＭＡＸ相セラミックスとしてのＴｉ3Ａｌ（Ｃ0.95Ｎ0.05）2を得た。得られたＴｉ3Ａｌ（Ｃ0.95Ｎ0.05）2について乳鉢と乳棒を用いて粗粉砕した後、ＩＰＡ中で５ｍｍのジルコニアボールを用いたボールミル粉砕を２４時間行った。その後、０．５ｍｍのジルコニアボールを用いた遊星ボールミル粉砕（２００ｒｐｍ、１５分を３回）行い、懸濁液を得た。懸濁液に対してエバポレータでＩＰＡを除去して約３μｍに粉砕されたＴｉ3Ａｌ（Ｃ0.95Ｎ0.05）2粉末を得た。 Using a graphite resistance furnace, the uniformly mixed dry powder was placed in an alumina crucible and fired under the conditions of 1450 ° C. for 2 h (heating rate 10 ° C./min) in an Ar stream to obtain Ti 3 Al (C) as MAX phase ceramics. 0.95 N 0.05 ) 2 was obtained. The resulting Ti 3 Al(C 0.95 N 0.05 ) 2 was coarsely pulverized using a mortar and pestle, and then subjected to ball mill pulverization using 5 mm zirconia balls in IPA for 24 hours. Then, planetary ball mill pulverization (200 rpm, 15 minutes three times) using 0.5 mm zirconia balls was performed to obtain a suspension. IPA was removed from the suspension with an evaporator to obtain Ti 3 Al(C 0.95 N 0.05 ) 2 powder pulverized to about 3 μm.
　３００ｍＬの濃ＨＣｌにＬｉＦを１８ｇを入れた酸水溶液を準備し、氷で冷やしながら１０ｇのＴｉ3Ａｌ（Ｃ0.95Ｎ0.05）2粉末を入れて、２０℃から３０℃に制御された環境下で、２４時間、マグネチックスターラーで撹拌することで、Ａｌをエッチングして除去し、Ｔｉ3Ａｌ０．０２（Ｃ0.95Ｎ0.05）2　ＭＸｅｎｅからなる粒子材料を得た。エッチング後、ｐＨ６程度になるまで水洗し、最後に水をエタノールに置換した。この操作により、粒子材料は、エタノール中に懸濁されたＭＸｅｎｅの懸濁液を得た。 Prepare an acid aqueous solution of 18 g of LiF in 300 mL of concentrated HCl, add 10 g of Ti 3 Al(C 0.95 N 0.05 ) 2 powder while cooling with ice, and heat at 20° C. to 30° C. under a controlled environment. , and stirred with a magnetic stirrer for 24 hours to etch and remove Al to obtain a particulate material consisting of Ti 3 Al 0.02 (C 0.95 N 0.05 ) 2 MXene. After etching, it was washed with water until the pH reached about 6, and finally water was replaced with ethanol. By this operation, the particulate material obtained a suspension of MXene suspended in ethanol.
　原料懸濁液中の粒子濃度を測定し、ＭＸｅｎｅの粒子濃度が１５．０ｍｇ／ｍＬになるように水を添加することで、分散媒としての水中に分散したＭＸｅｎｅ（原料懸濁液）を得た。
・剥離工程
　この原料懸濁液に対して、ＺｒＯ2ビーズ径５０μｍのビーズミルをスラリー送入速度１５０ｍＬ／ｍｉｎ、ＺｒＯ2ビーズ充填量８０％の条件で処理を行うことで、ＭＸｅｎｅからなる剥離物を生成した。この処理を３回繰り返すことにより、原料懸濁液中に含まれるＭＸｅｎｅからなる粒子材料は、概ね全て剥離物になり、その剥離物を含む剥離物懸濁液を得た。 The particle concentration in the raw material suspension was measured, and water was added so that the MXene particle concentration was 15.0 mg/mL, thereby obtaining MXene (raw material suspension) dispersed in water as a dispersion medium. rice field.
・Exfoliation process This raw material suspension was processed in a bead mill with a ZrO2 bead diameter of 50 μm under the conditions of a slurry feed rate of 150 mL/min and a ZrO2 bead filling amount of 80%, thereby exfoliating the MXene . generated. By repeating this treatment three times, almost all of the particle material composed of MXene contained in the raw material suspension became exfoliated matter, and an exfoliated matter suspension containing the exfoliated matter was obtained.
　得られた剥離物懸濁液について、ピラニア処理（Ｈ2ＳＯ4：Ｈ2Ｏ2＝３体積部：１体積部の混合液に浸漬）したＳｉ基板上に滴下し、ＡＦＭ分析を行った。ＡＦＭ像を図１に示す。剥離した剥離物（ナノシート）を無作為に１００個抜き取り、ＡＦＭにより測定した厚さの平均値を求め表１に示す。さらにＳＥＭ観察の結果を図２に示す。剥離物を無作為に１００個抜き取り、ＳＥＭ写真より縦（厚み方向に直交する方向での最大径）と横（縦方向及び厚み方向に直交する方向）の寸法を測定し、その平均値をその剥離物の大きさと定義し、１００個の剥離物の大きさの平均値を表１に示す。 The resulting exfoliated material suspension was dropped onto a piranha-treated Si substrate (immersed in a mixed solution of H 2 SO 4 :H 2 O 2 =3 parts by volume:1 part by volume) and subjected to AFM analysis. An AFM image is shown in FIG. 100 exfoliated exfoliated products (nanosheets) were randomly sampled, and the average value of the thickness measured by AFM was obtained and shown in Table 1. Furthermore, the result of SEM observation is shown in FIG. 100 exfoliated products were randomly selected, and the vertical (maximum diameter in the direction perpendicular to the thickness direction) and horizontal (direction perpendicular to the vertical and thickness directions) dimensions were measured from the SEM photograph, and the average value was calculated. Table 1 shows the average value of the size of 100 exfoliated objects.
　前処理工程で用いたＴｉ3Ａｌ（Ｃ0.95Ｎ0.05）2の粉末Ａと、剥離物（ＭＸｅｎｅのナノシート）とのそれぞれについて、ＸＲＤ測定し、図３に示す。それぞれのXRDプロファイルから（００２）面の層間距離を表２に示す。 XRD measurement was performed on each of the powder A of Ti 3 Al(C 0.95 N 0.05 ) 2 used in the pretreatment step and the exfoliated product (nanosheet of MXene), and the results are shown in FIG. Table 2 shows the interlayer distance of the (002) plane from each XRD profile.
　剥離物懸濁液（15.0 mg/ml）を37000G（17000rpm）、30分間遠心沈降させ、上澄みを廃棄した後、ジメチルスルホキシド（DMSO）を沈降物1.25gあたり5.0g添加し、振とう機にて140rpm、振幅45mm、1.5h撹拌することで懸濁させた。これらの操作を３回繰り返して分散媒を全てＤＭＳＯに置換してＤＭＳＯサスペンジョンを得た。 Centrifuge the exfoliate suspension (15.0 mg/ml) at 37000G (17000rpm) for 30 minutes, discard the supernatant, add 5.0 g of dimethyl sulfoxide (DMSO) per 1.25 g of sediment, and shake with a shaker. Suspended by stirring at 140 rpm, amplitude 45 mm, 1.5 h. These operations were repeated three times to replace all the dispersion medium with DMSO to obtain a DMSO suspension.
　得られたDMSOサスペンジョンについて、2400G（3500rpm）で遠心分離し、上澄みを採取する（上澄みをDMSO colloidsと名付ける）。DMSO colloids 2滴にエタノールを1滴滴下しspin coatのサンプルとする。ピラニア処理したガラス板（25×25×0.7mm）を基板とし、20μL滴下して、4000rpm、1分の条件でスピンコートを行い、膜を作製した。 　The resulting DMSO suspension is centrifuged at 2400 G (3500 rpm) and the supernatant is collected (the supernatant is named DMSO colloids). Add 1 drop of ethanol to 2 drops of DMSO colloids and use it as a spin coat sample. A piranha-treated glass plate (25×25×0.7 mm) was used as a substrate, and 20 μL of the solution was dropped and spin-coated at 4000 rpm for 1 minute to form a film.
　膜厚制御のためスピンコートによる薄膜作製を繰り返す時は、自然乾燥した後、同様にspin coatによる膜作製を必要な膜厚になるまで行った。UV-vis測定した結果を図4に示す。200℃ 24h真空乾燥した後、表面電気抵抗を測定した結果を表３に示す。
（実施例２）
　TiC粉末（TI-30-10-0020、レアメタリック社）9.2g、TiN粉末（TN-30-10-0020、レアメタリック社）3.2g、Ti粉末（TIE07PB 3N、高純度化学）4.9g、Al粉末（ALE15PB 3NG、高純度化学）2.8gを出発原料に用いた以外、実施例1と同様に剥離物を調製した。図1にAFM像、表1に平均厚さと平均大きさ、表２に層間距離、図2にSEM像、図3に得られたTi3Al（C0.75N0.25）2粉末、Ti3 Al0.02（C0.75N0.25）2 MXeneのXRDプロファイル、図4にUV-visの結果、表３に表面電気抵抗値を示す。
（比較例１）
　TiC粉末（TI-30-10-0020、レアメタリック社）12.3g、Ti粉末（TIE07PB 3N、高純度化学）4.9g、Al粉末（ALE15PB 3NG、高純度化学）2.8gを出発原料に用いた以外、実施例1と同様に剥離物としてのTi3Al0.02C2 MXene ナノシートを作製した。図1にAFM像、表1に平均厚さと平均大きさ、表２に層間距離、図2にSEM像、図3に得られたTi3AlC2粉末、Ti3Al0.02C2  MXeneのXRDプロファイル、表３に表面電気抵抗値を示す。
（比較例２）
　TiC粉末（TI-30-10-0020、レアメタリック社）4.4g、TiN粉末（TN-30-10-0020、レアメタリック社）4.6g、Ti粉末（TIE07PB 3N、高純度化学）7.1g、Al粉末（ALE15PB 3NG、高純度化学）4.0gを出発原料に用いた以外、実施例1と同様に剥離物としてのTi3Al0.02（C0.5 N0.5）2 MXene ナノシートを作製した。図2にSEM像、図3に得られたTi3Al（C0.5N0.5）2粉末、Ti3Al0.02（C0.5 N0.5）2  MXeneのXRD プロファイルを示す。
（比較例３）
　TiC粉末（TI-30-10-0020、レアメタリック社）12.3g、Ti粉末（TIE07PB 3N、高純度化学）4.9g、Al粉末（ALE15PB 3NG、高純度化学）2.8gを出発原料に用いて比較例2と同様にTi3AlC2粉末を作製し、剥離工程を行う際の分散媒としてエタノールを用いた以外、比較例2と同様に剥離物としてのTi3Al0.02C2 MXene ナノシートを作製した。図1にAFM像、表1に平均厚さと平均大きさ、表２に層間距離、図2にSEM像、図3に得られたTi3AlC2粉末、Ti3Al0.02C2 MXeneのXRD プロファイルを示す。 When repeating thin film formation by spin coating for film thickness control, after air drying, film formation by spin coating was repeated in the same manner until the required film thickness was obtained. Figure 4 shows the results of UV-vis measurements. Table 3 shows the results of measuring the surface electrical resistance after vacuum drying at 200°C for 24 hours.
(Example 2)
TiC powder (TI-30-10-0020, Rare Metallic) 9.2 g, TiN powder (TN-30-10-0020, Rare Metallic) 3.2 g, Ti powder (TIE07PB 3N, Kojundo Chemical) 4.9 g, Al A stripped product was prepared in the same manner as in Example 1, except that 2.8 g of powder (ALE15PB 3NG, Kojundo Chemical) was used as the starting material. Fig. 1 shows AFM image, Table 1 shows average thickness and average size, Table 2 shows interlayer distance, Fig. 2 shows SEM image, Fig. 3 shows Ti3Al ( C0.75N0.25 ) 2 powder and Ti3Al0.02 obtained . (C 0.75 N 0.25 ) 2 MXene XRD profile, FIG. 4 shows UV-vis results, and Table 3 shows surface electrical resistance values.
(Comparative example 1)
Except that 12.3 g of TiC powder (TI-30-10-0020, Rare Metallic), 4.9 g of Ti powder (TIE07PB 3N, Kojundo Chemical), and 2.8 g of Al powder (ALE15PB 3NG, Kojundo Chemical) were used as starting materials. , Ti 3 Al 0.02 C 2 MXene nanosheets were produced as exfoliated products in the same manner as in Example 1. Fig. 1 is AFM image, Table 1 is average thickness and average size, Table 2 is interlayer distance, Fig. 2 is SEM image, Fig. 3 is XRD profile of obtained Ti 3 AlC 2 powder and Ti 3 Al 0.02 C 2 MXene. , Table 3 shows the surface electrical resistance values.
(Comparative example 2)
TiC powder (TI-30-10-0020, Raremetallic) 4.4g, TiN powder (TN-30-10-0020, Raremetallic) 4.6g, Ti powder (TIE07PB 3N, Kojundo Chemical) 7.1g, Al A Ti 3 Al 0.02 (C 0.5 N 0.5 ) 2 MXene nanosheet was prepared as an exfoliated product in the same manner as in Example 1, except that 4.0 g of powder (ALE15PB 3NG, Kojundo Chemical) was used as the starting material. Fig. 2 shows the SEM image, and Fig. 3 shows the XRD profiles of the obtained Ti3Al ( C0.5N0.5 ) 2 powder and Ti3Al0.02 ( C0.5N0.5 ) 2MXene .
(Comparative Example 3)
Comparison using 12.3 g of TiC powder (TI-30-10-0020, Rare Metallic), 4.9 g of Ti powder (TIE07PB 3N, Kojundo Chemical), and 2.8 g of Al powder (ALE15PB 3NG, Kojundo Chemical) as starting materials Ti 3 AlC 2 powder was produced in the same manner as in Example 2, and Ti 3 Al 0.02 C 2 MXene nanosheets were produced as exfoliated materials in the same manner as in Comparative Example 2, except that ethanol was used as the dispersion medium in the exfoliation step. . Fig. 1 is AFM image, Table 1 is average thickness and average size, Table 2 is interlayer distance, Fig. 2 is SEM image, Fig. 3 is XRD profile of obtained Ti 3 AlC 2 powder and Ti 3 Al 0.02 C 2 MXene. indicates
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
比較例２については粒子が粉砕されてシート状にならず、シートの平均厚さ及び平均大きさが測定できなかった。 In Comparative Example 2, the particles were pulverized and did not form a sheet, and the average thickness and average size of the sheet could not be measured.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
（結果）
　ｘが０．９７～０．７の範囲内に入っている実施例１及び２は、ｘが１である比較例１及び３と比べて平均厚さが薄く、平均大きさが大きくなることが分かった。また、ｘが０．５である比較例２では剥離工程で粉砕が進行して微細な粒子しか生成できなかった。Ｃサイトの一部をＮにより置き換えると、親水性官能基が吸着しやすくなり、層間の結合力が弱まり、剥離しやすくなるため好ましいが、余りにＮにて置き換えすぎると層間の結合力が弱まり、剥離と同時に容易に粉砕が著しく進行し微細な粉末となった。また、実施例１及び２は、比較例１よりも光線透過性に優れることが分かった。 (result)
Examples 1 and 2 in which x is in the range of 0.97 to 0.7 have a smaller average thickness and a larger average size than Comparative Examples 1 and 3 in which x is 1. Do you get it. In addition, in Comparative Example 2 where x is 0.5, pulverization progressed in the peeling process and only fine particles could be produced. When a part of the C site is replaced with N, the hydrophilic functional group is likely to be adsorbed, the bonding strength between layers is weakened, and peeling is facilitated. Simultaneously with the peeling, pulverization proceeded remarkably easily and became a fine powder. Moreover, it was found that Examples 1 and 2 are superior to Comparative Example 1 in light transmittance.
　剥離工程を行う際の分散媒をエタノールのみとした比較例３では、平均厚さが大きく平均大きさが小さくなり、十分に剥離させることができなかった。更に（００２）面の層間距離も小さかった。このように水を含有しない分散媒を用いて剥離工程を行うよりも水を含有する分散媒を用いる方が、薄くて大きなナノシートを得る上で、微小ビーズを用いたビーズミルによる手法で剥離させる際に、好ましいことが分かった。 In Comparative Example 3, in which only ethanol was used as the dispersion medium during the peeling process, the average thickness was large and the average size was small, and sufficient peeling could not be achieved. Furthermore, the interlayer distance of the (002) plane was also small. Using a dispersion medium containing water rather than using a dispersion medium that does not contain water in this way is better for obtaining thin and large nanosheets, and when peeling by a bead mill technique using microbeads. was found to be favorable.
　MXeneの剥離は超音波照射で行い、剥離した一部のMXeneナノシートを遠心分離で採取する手法で得ていたが、産業に利用できるレベルとは言えなかった。溶媒に超音波を照射するとキャビテーションが発生し、その圧壊により、粉体どうしが衝突するメカニズムで層状化合物を構成する層の剥離が進行する。しかしながら、キャビテーションの発生が起きやすい水を用いたとしても剥離が進行するのは一部のみである。さらに遊星ボールミルによる手法によると剥離よりも粉砕が優先され、表面酸化が進行するためMXeneについては検討もされていないのが現状であった。
MXeneの炭素サイトの一部を窒素に置き換えると、親水性官能基がより吸着することにより層間の結合力が弱まり、微小ビーズを用いたビーズミルでMXeneの層間に選択的に物理的作用力を付与することにより、遠心分離で分級することなく、平均厚さが薄くて平均大きさが大きなMXeneナノシートを得ることに成功した。MXeneナノシートを産業で利用できるレベルに至ったと言える。 MXene was exfoliated by ultrasonic irradiation, and a part of the exfoliated MXene nanosheets was collected by centrifugation. When a solvent is irradiated with ultrasonic waves, cavitation occurs, and due to the crushing of the cavitation, the layers that make up the layered compound are exfoliated by the mechanism of powder collision. However, even if water, which tends to cause cavitation, is used, the peeling progresses only partially. Furthermore, according to the method using a planetary ball mill, pulverization takes precedence over exfoliation, and surface oxidation progresses, so MXene has not been studied at present.
Replacing some of the carbon sites of MXene with nitrogen weakens the bonding force between the layers by adsorbing more hydrophilic functional groups, and a bead mill using microbeads selectively imparts a physical force between the layers of MXene. By doing so, we succeeded in obtaining MXene nanosheets with a small average thickness and a large average size without centrifugation. It can be said that MXene nanosheets have reached a level where they can be used in industry.
　剥離工程において、MXene粒子濃度を１０mg/mＬ以上にすることで、剥離工程の効率が高くなり、２０mg/mＬ以下にすることでＭＸｅｎｅを未剥離物の残存が抑制できて剥離物にすることが容易になった。 In the stripping process, the concentration of MXene particles of 10 mg/mL or more increases the efficiency of the stripping process, and the concentration of MXene particles of 20 mg/mL or less suppresses the remaining of the unstripped material and makes it a stripped material. made easier.
　剥離工程において水を用いて平均厚さが小さい剥離物を得られるようになったが、そのままでは酸化によるＭＸｅｎｅの劣化が観察されたが、実施例のように分散媒をＤＭＳＯにて置換することにより酸化が抑制できることが明らかになった。なお、分散液中の濃度を０．４質量％以下にすることで効果的に凝集を抑制することができることが分かった。 It became possible to obtain a stripped product with a small average thickness using water in the stripping process, but deterioration of MXene due to oxidation was observed as it was. It was found that oxidation can be suppressed by In addition, it turned out that aggregation can be effectively suppressed by setting the concentration in the dispersion liquid to 0.4% by mass or less.

Claims (5)

  1. 　平均厚さ1.0～3.5nm、平均大きさ1.5～2.0μmであり、（００２）面の層間距離が１．３５０nm～１．４００nmであるTi3Ala（CxN1-x）2、x=0.97～0.70、aが0.02超、で構成されるMXeneナノシートを有する粒子材料。 Ti 3 Al a (C x N 1-x ) 2 ,x having an average thickness of 1.0 to 3.5 nm, an average size of 1.5 to 2.0 μm, and an interlayer distance of (002) planes of 1.350 nm to 1.400 nm = 0.97-0.70, a is greater than 0.02, having MXene nanosheets.
  2. 水中ｐH６からｐH８におけるゼーター電位が－２９．０ｍVから－３４．０ｍVの範囲である請求項１に記載の粒子材料。 2. The particulate material of claim 1, wherein the zeta potential at pH 6 to pH 8 in water is in the range of -29.0 mV to -34.0 mV.
  3. 　請求項１又は２に記載の粒子材料と、
    　前記粒子材料を０．１質量％～０．４質量％で分散し、ジメチルスルホキシドを５０質量％以上含有する分散媒と、
    　を有する分散液。     a particulate material according to claim 1 or 2;
    a dispersion medium containing 0.1% to 0.4% by mass of the particulate material and containing 50% by mass or more of dimethylsulfoxide;
    A dispersion having
  4. 　１０μｍ～３００μｍのビーズを用いたビーズミルにおいて、水を５０質量％以上含有する分散媒と、粒子濃度10mg/mＬ～２０mg/mＬで前記分散媒に分散されたＭＸｅｎｅとの混合物に対して処理することで、前記ＭＸｅｎｅを剥離して剥離物を形成する剥離工程を有するＭＸｅｎｅナノシートからなる粒子材料の製造方法。 In a bead mill using beads of 10 μm to 300 μm, processing a mixture of a dispersion medium containing 50% by mass or more of water and MXene dispersed in the dispersion medium at a particle concentration of 10 mg/mL to 20 mg/mL. 3. A method for producing a particulate material composed of MXene nanosheets, which includes a peeling step of peeling the MXene to form a peeled product.
  5. 　請求項４に記載の粒子材料の製造方法における前記剥離工程と、
    　前記剥離工程後に含有する水をジメチルスルホキシドに置換してジメチルスルホキシド中に前記粒子材料を分散させた分散液とする工程と、
    を有する分散液の製造方法。     The peeling step in the method for producing a particulate material according to claim 4;
    a step of replacing the water contained after the peeling step with dimethylsulfoxide to obtain a dispersion in which the particulate material is dispersed in dimethylsulfoxide;
    A method for producing a dispersion having
PCT/JP2021/018297 2021-05-13 2021-05-13 Particle material composed of novel mxene nanosheets, dispersion containing said particle material, and method for producing said particle material WO2022239210A1 (en)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20140162130A1 (en) * 2011-06-21 2014-06-12 Drexel University Compositions comprising free-standing two-dimensional nanocrystals
WO2020136865A1 (en) * 2018-12-28 2020-07-02 株式会社アドマテックス Mxene particulate materials, method for producing these particulate materials, and secondary battery
WO2020136864A1 (en) * 2018-12-28 2020-07-02 株式会社アドマテックス Mxene particulate material, slurry, secondary battery, transparent electrode, and method for producing mxene particulate material

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20140162130A1 (en) * 2011-06-21 2014-06-12 Drexel University Compositions comprising free-standing two-dimensional nanocrystals
WO2020136865A1 (en) * 2018-12-28 2020-07-02 株式会社アドマテックス Mxene particulate materials, method for producing these particulate materials, and secondary battery
WO2020136864A1 (en) * 2018-12-28 2020-07-02 株式会社アドマテックス Mxene particulate material, slurry, secondary battery, transparent electrode, and method for producing mxene particulate material

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