WO2023089739A1 - Matériau particulaire composite, son procédé de production et électrode - Google Patents

Matériau particulaire composite, son procédé de production et électrode Download PDF

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WO2023089739A1
WO2023089739A1 PCT/JP2021/042466 JP2021042466W WO2023089739A1 WO 2023089739 A1 WO2023089739 A1 WO 2023089739A1 JP 2021042466 W JP2021042466 W JP 2021042466W WO 2023089739 A1 WO2023089739 A1 WO 2023089739A1
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mxene
composite
mass
composite particle
particle material
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PCT/JP2021/042466
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Japanese (ja)
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仁俊 佐藤
実 長田
友祐 渡辺
寛之 恩田
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/JP2021/042466 priority Critical patent/WO2023089739A1/fr
Priority to JP2023562018A priority patent/JPWO2023089739A1/ja
Publication of WO2023089739A1 publication Critical patent/WO2023089739A1/fr

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
    • H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
    • H01G11/02—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof using combined reduction-oxidation reactions, e.g. redox arrangement or solion
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
    • H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
    • H01G11/22—Electrodes
    • H01G11/30—Electrodes characterised by their material
    • H01G11/46—Metal oxides
    • 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
    • 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

Definitions

  • the present invention relates to a novel composite particle material of MXene nanosheets and microparticles, a method for producing the same, and an electrode using the composite particle material.
  • 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
  • Positive and/or negative electrode active materials for pseudocapacitors also called redox capacitors that utilize electrochemical reactions involving faradaic currents associated with electrochemical adsorption and desorption reactions of ions at the electrodes, and Due to its excellent properties, it is expected to be applied to electromagnetic wave shielding thin films and conductive thin films.
  • 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 1 to 3.
  • MXene nanosheets are used in secondary batteries (storage batteries) and pseudocapacitors, not only MXene nanosheets but also acetylene black is added as a conductive aid.
  • acetylene black is added as a conductive aid.
  • the composite particle material previously filed by the present applicant is an aggregate of primary particles. Therefore, pulverization and classification are essential for industrial use.
  • pulverization which is generally performed by applying physical stress to agglomerates, it seems possible to pulverize them to a particle size that can be used in practice, but it was found that the agglomerate structure was locally destroyed. .
  • the strength of aggregates is affected by the humidity environment, and thus the aggregate structure obtained differs depending on the season, making it impossible to obtain an industrially usable composite particle material.
  • the characteristics will be significantly deteriorated, and if the crushing that applies physical stress is performed, the particle shape will become irregular and uniform at the time of electrode preparation.
  • problems such as the inability to form a thin film.
  • the present invention has been completed in view of the above circumstances, and provides a powder having a 3D porous aggregation structure with a high specific surface area, in which the novel MXene nanosheets and microparticles are highly dispersed, and which has a high sphericity.
  • the problem to be solved is to provide a particulate material, a method for producing the same, and an electrode using the composite particulate material.
  • the composite particle material of the present invention which solves the above problems, contains 3 to 10 parts by mass of conductive microparticles and Ti 3 Al a (C( 1.0 -x )N x ) 2 , (0 ⁇ x ⁇ 0 .25, a is 0.01 or more) MXene nanosheets containing 90 to 97 parts by mass as primary particles, the MXene nanosheets having an average thickness of 1.0 to 3.5 nm, and having the following interdispersion degree: It has a volume average diameter of 0.01 to 7.00, a volume average diameter of 1.0 ⁇ m to 15.0 ⁇ m, and a sphericity of 0.80 or more.
  • interdispersion degree Calculate 100 ratios (B/A) of peak height A at 400 cm ⁇ 1 and peak height B at 1332 cm ⁇ 1 in Raman spectroscopic analysis using a laser with a wavelength of 532 nm, and the 100 B/A values The standard deviation calculated from is taken as the degree of interdispersion.
  • the method for producing a composite particle material of the present invention that solves the above problems comprises: Ti3Ala (C( 1.0 -x ) Nx ) 2 , (0 ⁇ x ⁇ 0.25, a is 0.01 or more) a stripping step of stripping MXene to form a stripped product; an acid treatment step of treating raw carbon microparticles in a mixed acid aqueous solution of sulfuric acid and nitric acid at 70° C.
  • An alkaline aqueous solution of 0.4 to 0.7 mol/L is added to the mixture slurry to make the liquid alkaline and aggregate to form the Ti 3 Al a (C( 1.0 -x )N x ) 2 , (0 ⁇ x ⁇ 0.25, a is 0.01 or more) an aggregation step of obtaining a slurry of aggregates of MXene and the carbon fine particles;
  • the composite particle material of the present invention can provide an electrode that can exhibit high performance when used in secondary batteries (storage batteries) and pseudocapacitors by adopting it as an active material.
  • the method for producing a composite particle material of the present invention makes it possible to produce a composite particle material having an ideal 3D porous aggregation structure and a high degree of sphericity by using the production method having the above configuration. .
  • FIG. 4 is an AFM image of a peeled product obtained in the peeling step of Example 1.
  • FIG. 4 is an SEM photograph of a peeled product obtained in the peeling step of Example 1.
  • FIG. 2 is the XRD profile of Ti 3 AlC 2 and composite powder material of Example 1.
  • FIG. 1 is a SEM photograph of the composite powder material of Example 1.
  • FIG. 2 shows adsorption isotherms of composite powder materials of Example 1, Example 2 and Comparative Example 4.
  • FIG. 4 is an AFM image of a peeled product obtained in the peeling step of Example 2.
  • FIG. 4 is an SEM photograph of a peeled product obtained in the peeling step of Example 2.
  • FIG. 4 is an SEM photograph of the composite powder material of Comparative Example 2.
  • FIG. FIG. 2 is a schematic diagram showing a unit cell of MAX
  • the composite particle material, manufacturing method thereof, and electrode material of the present invention will be described in detail below based on embodiments.
  • the composite particle material of the present embodiment has excellent electrical properties such as conductivity, and has a large void layer formed in the crystal due to the removal of the Al layer.
  • secondary batteries, Na-ion secondary batteries, etc. active materials such as pseudocapacitors (negative electrode active materials in the case of secondary batteries, and positive and/or negative electrode active materials in the case of pseudocapacitors), electromagnetic wave shielding thin films and conductive thin films
  • the numerical values described in this specification can be used as upper and lower limits of numerical ranges, and in such cases, the range can be either inclusive or exclusive of the numerical values.
  • the composite particle material of the present embodiment is a particle material obtained by combining a thin piece of MXene and a particulate or tube-like minute body for application to an electrode material or the like.
  • MXene exfoliated particulate material is obtained by exfoliating multi-layer MXene, which is a powdery layered compound of several microns.
  • the composite particle material of this embodiment is a composite particle material of MXene and microparticles.
  • MXene contains 90 to 97% based on the sum of the mass of MXene and minute bodies, and the remaining 10% to 3% is minute bodies. If the content of MXene exceeds 97%, the effect as a barrier against drying shrinkage due to the addition of fine particles is weakened, and if the content is lower than 90%, the function as an active material deteriorates. Furthermore, when the content of MXene exceeds 97%, electrons are difficult to move to the current collector, and when it is less than 90%, the function as an active material deteriorates. The lower limits of the MXene content are 93%, 92% and 90%, and the upper limits are 97%, 96% and 95%.
  • the composite particulate material has a mutual dispersity of 0.01 to 7.00.
  • the interdispersion degree is a value that defines the degree of dispersion between the MXene and the minute particles.
  • the degree of interdispersion of 100 randomly selected composite particle materials was determined by Raman spectroscopic analysis using a laser with a wavelength of 532 nm with a peak height A of 400 cm ⁇ 1 and The standard deviation calculated from the ratio (B/A) of the peak heights B at 1332 cm -1 is defined as the degree of interdispersion. It is desirable that the interdispersion degree is small, and if it exceeds 7.00, electrons cannot effectively move to the current collector.
  • the interdispersion degree of the composite particle material can adopt lower limits of 0.01, 0.05, 0.10 and upper limits of 7.00, 2.50, 1.50. .
  • MXene nanosheet exfoliated to the monolayer level can be easily oxidized to precipitate anatase, analyze at a laser intensity that does not precipitate anatase. Analysis is performed in the range from 100 cm -1 to 2000 cm -1 .
  • Vibration due to functional groups adsorbed on titanium atoms of MXene nanosheet is 230 to 470 cm. At ⁇ 1 (A peak), vibration due to functional groups adsorbed on carbon atoms appears at 580 cm ⁇ 1 . On the other hand, for acetylene black, the SP3 hybrid orbital carbon appears at 1332 cm ⁇ 1 (B peak), and the SP2 hybrid orbital carbon appears at 1500 to 1600 cm ⁇ 1 .
  • the composite particulate material has a specific surface area of 75 m 2 /g or more.
  • the specific surface area is measured by the BET method using nitrogen after heating at 110° C. for 6 hours in vacuum as a pretreatment.
  • 75 m 2 /g, 80 m 2 /g and 105 m 2 /g can be adopted as lower limits, and 200 m 2 /g, 185 m 2 / g and 170 m 2 /g as upper limits. can be adopted.
  • the composite particulate material preferably has an average pore diameter of 10.0-20.0 nm and an average pore volume of 0.30-0.70 mL/g.
  • the average pore diameter is 10.0-15.0 nm and the average pore volume is 0.40-0.60 mL/g.
  • the average pore diameter and pore volume were measured by the BET method using nitrogen after heating in vacuum at 110° C. for 6 hours as a pretreatment.
  • a slurry of agglomerated particulate material is prepared in a liquid, centrifugally sedimented, the sediment is air-dried at room temperature, and then vacuum-dried at 60°C to prepare agglomerates. and then pulverized by applying physical stress to produce a composite particulate material that is secondary particles. It takes more than 24 hours to air dry. It shrinks during air drying and vacuum drying at 60°C. As for the shrinkage mechanism, the MXene nanosheets are overlapped and integrated, and at the same time, the carbon particles added as a shrinkage barrier move. Such a mechanism lowers the degree of interdispersion and lowers the specific surface area.
  • the average pore diameter and average pore volume are also reduced. After air-drying, if it is dried in a vacuum at 110°C, it will shrink significantly and the specific surface area will decrease significantly. On the other hand, when a slurry of composite aggregated particles in an alcohol solvent is spray-dried, the droplets are dried instantaneously without shrinkage, resulting in a spherical composite particle material having a 3D porous aggregate structure with excellent interdispersion and a high specific surface area. Obtainable. In the method of obtaining a composite particle material by spray drying, which dries instantly, the specific surface area is reduced compared to the general method of obtaining a composite particle material, which is secondary particles, by applying physical stress to agglomerates. As the size increases, the average pore diameter and average pore volume increase.
  • the 3D porous aggregation structure means a structure in which pores are formed in a three-dimensional network by aggregation of primary particles with interstices.
  • the composite particle material preferably has a mass change of 1.0% or less when 0.3 g of a sample is evenly spread on a dish of 20 cm 2 or more and heated at 110° C. in vacuum for 5 hours. Under this heating condition, the water contained in the MXene layers and the water adhering to the outer surface volatilize, but by specifying the amount, it is possible to define a composite particle material with a low water content between the layers. As the mass change, upper limits of 0.8%, 0.6%, 0.4%, and 0.2% can be adopted. The mass change within the specified range means the amount of moisture adsorbed from the air on the outer surface of the composite particulate material, not the water in the MXene layers.
  • the composite particulate material is preferably dried at 100-120° C. under vacuum or inert atmosphere.
  • the composite particulate material preferably has a bulk density of 0.1-0.5 g/cm 3 .
  • 0.1 g/cm 3 and 0.15 g/cm 3 can be adopted, and as upper limits, 0.45 g/cm 3 and 0.50 g/cm 3 can be adopted.
  • the method for producing an electrode film when producing a cell of a secondary battery or a pseudocapacitor but it is preferable to produce the composite particle material to be contained so that the volume packing density is as high as possible.
  • continuous particle blending particle size of compounded composite particle material mean that the particle size distribution changes continuously, and the particle size distribution is relatively broad.
  • particle size of compounded composite particle material mean that the particle size distribution changes continuously, and the particle size distribution is relatively broad.
  • MXene is a formula representing the aforementioned MAX phase, M n+1 AX n (M is a transition metal, A is an A group element, X is C, or [C (1.0-x) N x (0 ⁇ x ⁇ 1. 0)] and n is obtained by using Al as A in 1 to 3) and removing the Al phase by acid treatment.
  • Ti3Ala (C( 1.0 -x ) Nx ) 2 , (0 ⁇ x ⁇ 0.25, a is 0.01 or more ) is preferable.
  • the lower limit of a can be 0.002. More preferably, the upper limit of a is 0.05.
  • the bead mill treatment using microbeads promotes microparticulation rather than exfoliation, making it impossible to obtain thin and large nanosheets.
  • it can have O, OH, and halogen groups as surface functional groups.
  • MXene has a plate-like, leaf-like, flake-like, sheet-like, etc., and is generically defined as sheet-like.
  • the stacking direction of the layers of the stratified compound is defined as "thickness", and countless directions perpendicular to the thickness are defined as "sheet spread directions”.
  • the MXene has an average thickness of 1.0 to 3.5 nm, preferably 1.5 to 3.0 nm.
  • the average thickness is calculated as the average value of 100 randomly selected particles measured by AFM analysis using a hydrophilized Si wafer.
  • the size of the sheet can be measured by dropping a nanosheet onto a hydrophilized Si wafer and using an SEM.
  • the average size of the sheet in the spreading direction is preferably 0.1 to 2.0 ⁇ m, more preferably 0.1 to 1.7 ⁇ m.
  • the maximum value in the direction perpendicular to the thickness is the “long side” and the minimum value is the “short side”
  • 100 randomly selected particles were measured by SEM, [(long side + short side) / 2 ] is taken as the average size in the spreading direction.
  • Ti3Al0.02C2MXene has an average thickness of 1 .74 nm with an average size of 0.78 ⁇ m, but replacing 5% of the carbon sites with nitrogen gives an average thickness of 1.66 nm with an average size of 1.17 ⁇ m with 25% of the carbon sites replaced with nitrogen. , the average thickness is 1.81 nm and the average size is 1.61 ⁇ m. Replacing the carbon sites with nitrogen facilitates the formation of functional groups in water, lowering the interlayer bonding strength of MXene and yielding larger nanosheets at monolayer-level thicknesses.
  • the firing (synthesis) temperature of MAX phase ceramics is lowered within a range that does not generate impurities, so it is possible to reduce the average size while maintaining the thickness at the monolayer level. becomes.
  • the firing (synthesis) temperature of MAX phase ceramics is lowered from 1450° C. to 1430° C., the average thickness can be reduced to 2.06 nm and the average size to 0.25 ⁇ m. can.
  • the average thickness can be reduced to 1.98 nm and the average size to 0.10 ⁇ m.
  • the MXene nanosheet exfoliated to the monolayer level is made into a composite particle material without shrinkage, an electrode material with excellent ion diffusion can be obtained. Furthermore, a composite particle material with a high specific surface area can be obtained by using MXene nanosheets of an appropriate size. A composite particle material with a higher specific surface area can be obtained by reducing the average size while maintaining the thickness at the monolayer level.
  • the interlayer distance of the (002) plane of MXene obtained from XRD analysis is preferably from 1.400 nm to 1.700 nm.
  • the inter-layer distance of the void layer formed by removing the Al phase of the MAX phase by acid treatment is determined from the inter-layer distance of the (002) plane in the XRD of the MXene nanosheet powder to the (002) When defined as a value obtained by subtracting the interlayer distance of the plane, it is 0.770 nm to 0.470 nm.
  • the Li ion diameter is 0.18 nm and the Na ion diameter is 0.28 nm, and can be used as a negative electrode active material for Na ion secondary batteries in addition to Li ion secondary batteries.
  • the corresponding MAX phase ceramic powder is a particle material composed of a material having a value of 1 in the composition Ti3Ala (C( 1.0 -x ) Nx ) 2 of MXene to be measured. be. If the interlayer distance between the (002) planes of MXene nanosheets is less than 1.400 nm, deterioration occurs due to rapid charging and discharging when used as a negative electrode active material for Na-ion secondary batteries. If it exceeds 1.700 nm, the capacity per 1 g becomes small.
  • the microscopic object it is sufficient for the microscopic object to have a size on the order of nanometers, and being on the order of nanometers means that the length of the longest part of the length of the microscopic object is 100 nm or less.
  • the shape of the microscopic object may be any shape such as amorphous, spherical, thin film, and fibrous.
  • the fine particles preferably have a primary particle size of 100 nm or less, preferably 30 to 50 nm, and more preferably 30 to 40 nm, and may be aggregates.
  • the shape of the microscopic object is not limited, and spherical, sheet-like, tube-like, hollow, and irregular shapes can be exemplified.
  • minute bodies have electrical conductivity.
  • microscopic bodies include carbon microscopic bodies made of carbon materials and metal microscopic bodies made of metal materials.
  • fine carbon particles it is preferable to use those having high conductivity such as acetylene black, ketschen black, carbon nanotubes, graphene, carbon fiber, graphite powder, and hard carbon powder.
  • inorganic microscopic bodies composed of other inorganic substances can also be used as microscopic bodies.
  • TiO 2 , Al 2 O 3 , SiO 2 and BaTiO 3 having a primary particle size of 100 nm or less can be used as the inorganic fine particles.
  • the method for producing a composite particulate material of the present embodiment includes a peeling step, a mixing step, an aggregating step, a granulating step, and other necessary steps.
  • the method for producing the composite particulate material of the present embodiment is a production method that can be suitably employed for the production of the above-described composite particulate material of the present embodiment.
  • ⁇ Exfoliation step In the exfoliation step, microbeads are collided between the layers of multi-layered MXene, which are particles of several microns in size, in a dispersion medium to exfoliate them to obtain a nanosheet-like exfoliated slurry. be. Delamination proceeds between the layers of each layer of layered multilayer MXene.
  • the stripped material is not particularly limited, but one having about 1 to 3 layers is preferable.
  • the resulting exfoliated material becomes an exfoliated material suspension suspended in a 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 the particulate and layered multilayer MXene as a material is not particularly limited, the following method can be exemplified.
  • MXene is obtained by acid-treating a raw material consisting of Ti 3-layer MAX phase ceramic powder and partially dissolving the Al layer.
  • 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.
  • a portion of Al is dissolved in this particulate material by acid treatment to form a multi-layered MXene that is particulate and layered with a size of several microns.
  • an exfoliated material suspension in which nanosheet-like exfoliated material of MXene is suspended is obtained by a detachment step of bead mill treatment with high-speed rotation using beads of 10 ⁇ m to 300 ⁇ m.
  • the dispersion medium for the stripping step is not particularly limited, but preferably contains 50% by mass or more of water, and contains alcohols such as methanol, ethanol, and isopropanol, methyl ethyl ketone, acetone ketones, dimethylformamide, dimethyl sulfoxide, and the like. be able to. It is more preferable to make water 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 employed. 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. As a result, only a part of the particles can be separated, and a part of the particles must be separated by centrifugal separation.
  • MXene has been conventionally exfoliated by ultrasonic irradiation.
  • the solvent is irradiated with ultrasonic waves, cavitation is generated, and due to the crushing of the cavitation, the layers constituting the layered compound are exfoliated by the mechanism of powder collision.
  • peeling progresses only in part, and it cannot be said that it is at a level that can be used in industry.
  • peeling occurs in part, pulverization takes precedence, and surface oxidation proceeds remarkably due to the temperature rise. For this reason, a method of exfoliating only a part by ultrasonic irradiation and collecting by centrifugal separation has been adopted.
  • 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 more preferable. 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/min to 300 mL/min can be adopted.
  • a slurry particle concentration of 10.0 mg/mL to 20.0 mg/mL can be adopted.
  • the concentration is 10.0 mg/mL or less, the production efficiency of the MXene nanosheets will be poor, and if the concentration is 20.0 mg/mL or more, peeling will not proceed sufficiently, so this range is preferable.
  • 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% can be used for the filling amount of beads. When it is 40% or more, the efficiency of stripping is improved, and when it is 80% or less, it becomes easy to classify beads and slurry. Whether or not the desired particle material containing many sheet-like particles has been 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 exfoliation 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.
  • the MXene on a mass basis is turned into the exfoliated material by the bead mill treatment, more preferably 99% or more of the exfoliated material, and still more preferably 100% of the exfoliated material.
  • the peeling process is completed under the condition that all the MXene becomes the peeled substance, it becomes possible to use the MXene which is not peeled off as it is in the mixing process without removing it.
  • MXene other than exfoliated matter it can be separated by centrifugation, filtration, or the like.
  • the zeta potential of the exfoliated MXene obtained is measured in water of pH 6 to pH 8.
  • the zeta potential is measured at pH 7 unless there is a particular problem.
  • the zeta potential is preferably -25.0 mV to -35.0 mV. More preferably -28.0 mV to -34.0 mV.
  • the zeta potential of Ti 3 C 2 MXene nanosheets was ⁇ 28.9 mV.
  • the nanosheet in which 3% of the carbon sites are replaced with nitrogen is -29.3 mV
  • the nanosheet in which 5% of the carbon sites are replaced with nitrogen is -31.5 mV
  • the nanosheet in which 10% of the carbon sites are replaced with nitrogen is -32.1 mV
  • the carbon sites The nanosheet in which 15% of the carbon sites were replaced with nitrogen was ⁇ 32.4 mV
  • the nanosheet in which 25% of the carbon sites were replaced with nitrogen was ⁇ 33.1 mV.
  • the magnitude of the absolute value of the zeta potential can be rephrased as the amount of functional groups attached in water. When many functional groups in water are attached, the absolute value of zeta potential increases. Formation of suitable functional groups in water provides excellent releasability.
  • the zeta potential of MXene nanosheets and carbon microparticles is negative zeta potential explained in the mixing step. It is immobilized with Li ions and/or Na ions. A moderate zeta potential is necessary, and if the absolute value of the zeta potential is small, the resulting composite particle material will have a low degree of interdispersion and a low specific surface area. If the absolute value of the zeta potential is large, it becomes difficult for electrons to move. Therefore, it is preferable to select MXene nanosheets and carbon microparticles that have an appropriate absolute value of the zeta potential.
  • the atom% of Ti, Al, C, and N was used to calculate the amounts of Al, C, and N when Ti was 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.
  • the acid treatment step is a step of treating the raw carbon microparticles with a mixed acid solution of sulfuric acid and nitric acid to obtain highly hydrophilic carbon microparticles.
  • raw carbon fine particles include acetylene black, ketschen black, carbon nanotube, graphene, carbon fiber, graphite powder, and hard carbon powder.
  • Acetylene black, Ketsujen black, and carbon nanotubes are more preferred from the viewpoint of conductivity, and acetylene black is more preferred from the viewpoints of both conductivity, purity, and price.
  • a suspension of carbon microparticles suspended in the mixed acid is obtained, which can be used as it is in the mixing step, or the mixed acid can be washed repeatedly with water or the like to remove as much as necessary and used as carbon microparticles.
  • Washing can be performed until the pH of the washing solution reaches about 6, and further until the pH reaches about 6.5, 7, or 8.
  • the treatment temperature is preferably 70°C or higher. In particular, it is preferable to set the temperature to 95° C. or lower so as not to cause boiling.
  • the treatment time is not particularly limited, but hydrophilization can be ensured by treatment for 10 minutes or longer. Stirring or ultrasonic irradiation can be performed during the treatment. After the treatment, it may be subjected to the mixing step as it is, or the acid may be neutralized or separated. If the acid is neutralized or separated and the pH reaches a predetermined value or higher, the fine carbon particles aggregate, so neutralization can be carried out to the extent that the pH does not reach the predetermined value.
  • a method of separating the acid a method of separating the solid content by a classification operation such as centrifugation can be exemplified.
  • the mixing ratio of sulfuric acid and nitric acid can be about 4:1 to 1:1, preferably about 3:1 to 3:2 by volume.
  • the concentration of the mixed acid can be about 42% to 96%, preferably about 90.0% to 95.0%.
  • the obtained hydrophilic carbon microparticles preferably have a zeta potential of -20.0 mV to -25.0 mV in water of pH 6 to pH 8.
  • the zeta potential becomes negative because COOH and CO are adsorbed as functional groups.
  • the absolute value is smaller than ⁇ 20.0 mV, positively charged Li ions in water due to the addition of water-soluble Li salts and/or water-soluble Na salts with MXene nanosheets, which is a negative zeta potential explained in the mixing step. And/or it cannot be immobilized by Na ions, resulting in a composite particle material with a low interdispersion degree and a low specific surface area. It is preferable to select MXene nanosheets and carbon microparticles having moderate absolute values of zeta potential.
  • the mass ratio of the exfoliated matter and the carbon particles is 90:10 to 97:3, the concentration of the exfoliated matter is 11.5-17.0 mg/mL, and water is contained in an amount of 50% by mass or more. It is a step of obtaining a mixture dispersed in a second dispersion medium. More preferably, the second dispersion medium contains 100% by mass of water. By including other substances in the mixture, those substances can also be incorporated into the composite particulate material.
  • the negatively charged functional groups in water adsorbed to MXene and the negatively charged functional groups in water adsorbed to carbon microparticles are immobilized with positively charged Li ions and/or Na ions in water.
  • water-soluble lithium salts include lithium chloride and lithium carbonate
  • water-soluble sodium salts include sodium chloride and sodium carbonate.
  • a water-soluble salt of a strong alkali or strong acid is added and stirred for a long time, the MXene nanosheets and the water-soluble salt may react with each other, and lithium titanate or sodium titanate may precipitate locally on the MXene surface.
  • Water-soluble salts that remain neutral are preferred. It is preferable to add a water-soluble salt to the aqueous slurry of MXene in an amount of 0.8 mol/L to 1.0 mol/L. If it is less than 0.8 mol/L, it cannot be sufficiently immobilized, and if it exceeds 1.0 mol/L, many surplus ions remain. The mixture contains exfoliate at a concentration of 11.5-17.0 mg/mL.
  • the second dispersion medium may be the same as or different from the dispersion medium used in the peeling process and the solvent that can be used in other processes.
  • the second dispersion medium contains the dispersion medium used in the exfoliation step.
  • For the acid-treated carbon microparticles add a predetermined amount of carbon microparticles to pure water, and rotate at a rotation speed of 100 rpm to 300 rpm and an amplitude of 40 mm to 50 mm, more preferably at a rotation speed of 100 rpm to 200 rpm and 45 mm to 50 mm. It is preferable to add the deaggregated carbon fines water slurry to the MXene water slurry and mix them by stirring with a shaker for 12 hours or more under the amplitude condition of .
  • the conditions of the shaker at that time are preferably 100 to 300 rpm rotation speed and 40 to 50 mm amplitude.
  • the rotation speed is from 100 rpm to 200 rpm and the amplitude is from 45 mm to 50 mm.
  • MXene Acid-treated carbon microparticles Water slurry and water-soluble salt are added at the same time, and stirred for 4-6 hours using a shaker at a rotation speed of 100 rpm to 300 rpm and an amplitude of 40 mm to 50 mm.
  • a 0.4 to 0.7 mol / L alkaline aqueous solution is added to the mixture slurry obtained in the mixing step, and the pH of the liquid is increased to remove the exfoliated material contained in the mixture.
  • This is a step of aggregating the carbon particles to form aggregates dispersed in the liquid. It is preferable to raise the pH to about 12-14.
  • the alkaline aqueous solution is preferably lithium hydroxide and/or sodium hydroxide.
  • the pH is raised by adding an alkaline substance or by removing or diluting an acidic substance. It is preferable to increase the pH by adding the alkaline aqueous solution in several seconds and stirring within 1 hour with a shaker at a rotation speed of 100 rpm to 300 rpm.
  • the amplitude of the shaker at that time is preferably 40 mm to 50 mm. In both cases, when the rotational speed is 300 rpm or less, the destruction of the nanosheets is suppressed, and when it is 100 rpm or more, uniform mixing can be easily performed.
  • the alkaline aqueous solution is preferably added in an amount of 0.4 mol/L to 0.7 mol/L together with the amount of water contained in the aqueous slurry of the composite aggregated particle material.
  • the amount is 0.4 mol/L or more, sufficient aggregation can be achieved, and when the amount is 0.7 mol/L or less, residual surplus ions can be suppressed, which is preferable. If the addition amount is within this range, it is possible to obtain a composite particle material with a high specific surface area, for unknown reasons. Further, a highly hydrophobic organic solvent having a small dielectric constant can be added.
  • an alcohol slurry is prepared by replacing the main component of the dispersion medium contained in the aggregates dispersed in the liquid obtained in the aggregation process with alcohol, and the alcohol slurry is granulated by a spray drying method. It is a step of making granules by pressing.
  • the composite particle material of the present embodiment is obtained by directly or drying the granules. In this step, the droplets are instantly dried by a spray drying method, so that spherical granules having a porous structure can be obtained.
  • the method of replacing the main component of the dispersion medium contained in the aggregates dispersed in the liquid with alcohol is not particularly limited.
  • the alcohol content can be improved by simply adding alcohol, or the alcohol content can be improved by repeatedly removing the dispersion medium after adding the alcohol.
  • the dispersion medium can be removed by separating the dispersion medium separated by centrifugation as a supernatant or by evaporating the dispersion medium.
  • alcohol is the main component
  • content of alcohol is 50% or more based on the entire dispersion medium. %, preferably 99% by volume.
  • the alcohol that can be contained in the alcohol slurry is not particularly limited, but it is preferable to select an alcohol solvent that evaporates at a low temperature in order to further suppress the surface oxidation of the MXene nanosheets.
  • an alcohol solvent that evaporates at a low temperature for example, at least one of methanol, ethanol, and isopropanol is preferably used as the alcohol used as the dispersion medium.
  • alcohol it may contain water, ketones such as MEK, or DMSO.
  • the lower limit of the content of alcohol includes 99%, 95%, and 90% based on the volume of the dispersion medium.
  • the spray-drying method is performed in an inert atmosphere, which has low reactivity with each material that makes up the composite particle material.
  • an atmosphere filled with an inert gas such as nitrogen or argon, or a reduced pressure or vacuum atmosphere can be used.
  • the temperature of the inert atmosphere is the temperature at which the alcohol contained in the alcohol slurry can evaporate.
  • 80°C, 90°C, and 100°C can be adopted as the lower limit values of the temperature of the inert atmosphere
  • 100°C, 110°C, and 120°C can be adopted as the upper limit values.
  • the upper limit and lower limit can be arbitrarily combined.
  • the spray-drying method is performed by spraying droplets of a slurry of composite agglomerated material into a high-temperature atmosphere.
  • Usual methods such as a method of using a rotating disk and a method of using a nozzle such as a two-fluid nozzle can be employed as the method of spraying.
  • a method using a rotating disk is preferable in that the agglomerated particles in the alcohol slurry are unlikely to clog during spraying and that spherical granules having an arbitrary secondary particle size can be produced. Spherical granules having a required secondary particle size can be easily obtained by selecting the rotational speed of the rotating disk.
  • a step of granulating by a fluidized bed granulation method can be included.
  • the dispersion medium is instantaneously removed from the droplets composed of the sprayed composite agglomerated particle material and alcohol, the composite particle material is formed, resulting in a high specific surface area without shrinkage and excellent interdispersion of MXene nanosheets and carbon microparticles.
  • the solid content concentration which is preferably 1.0 to 10.0% by mass. More preferably 1.0 to 5.0% by mass.
  • the secondary particle size when the rotating disk method is used, a large secondary particle size can be obtained by lowering the number of revolutions and increasing the spray temperature.
  • a small secondary particle size can be obtained by increasing the rotational speed. Furthermore, a smaller secondary particle size can be obtained by reducing the aggregate particle size of the alcohol slurry of the composite aggregated particle material and spray-drying it using a nozzle such as a two-fluid nozzle. By combining these, an average secondary particle size of 1.0 ⁇ m to 15.0 ⁇ m can be obtained. 1.0 ⁇ m to 10.0 ⁇ m is more preferable. For spray drying using a nozzle such as a two-fluid nozzle, it is preferable to use an alcohol slurry from which large agglomerated particles have been removed through a sieve in order to prevent clogging of the nozzle.
  • the average secondary particle size is 1.0 ⁇ m or more, the composite particle material is less likely to scatter during work, which is preferable.
  • the average secondary particle size is preferably 1.0 ⁇ m to 15.0 ⁇ m. 1.0 ⁇ m to 11.0 ⁇ m is more preferable.
  • the granules obtained in the granulation step can be used as the composite particle material of the present embodiment as they are, but can be dried after that for the purpose of removing inter-layer water of the MXene nanosheets.
  • the drying step is a step of drying the granules at 100 to 120° C. under a vacuum atmosphere or an inert atmosphere to obtain the composite particle material of the present embodiment.
  • the vacuum atmosphere and the inert atmosphere are atmospheres employed to suppress oxidation of the MXene nanosheets, and any atmosphere that can suppress oxidation compared to air is sufficient.
  • the temperature of the drying process is determined by the temperature of the granules.
  • the temperature of the atmosphere is controlled, the granules are directly heated by infrared rays, etc., the temperature of the container containing the granules is controlled, and the granules are heated by heat transfer. You can control the temperature.
  • the temperature at which the drying process is performed is a temperature at which the MXene nanosheets are not denatured or within an allowable range of denaturation, and a temperature at which moisture contained between the layers of the MXene nanosheets can be removed.
  • Interlayer water can be effectively removed by performing the drying process.
  • a water content of less than 10% by weight, based on the total weight can easily be reached.
  • the time for performing the drying process is not particularly limited, but it is preferable to perform until the moisture content is less than 10% based on the total mass, or until the mass change is 1.0% or less per hour. . More preferably, the water content is 8% or less, 6% or less, 4% or less, 2% or less, or 1% or less, and the mass change is more preferably 0.5% or less per hour. .
  • the pretreatment step is an example of a method for manufacturing MXene.
  • a mixed raw material of TiC, TiN, Al, and Ti is pressurized in the range of 1 ton/cm 2 to 3 ton/cm 2 by CIP or uniaxial pressure, or pressurized.
  • it can be produced by contacting the MAX phase ceramic powder with an acidic substance at a temperature controlled at 20° C. to 30° C. to remove part of the Al element contained in the MAX phase ceramic powder.
  • the raw material to be subjected to the pretreatment step is represented by Ti3Ala (C( 1.0 -x ) Nx ) 2 , (0 ⁇ x ⁇ 0.25, a is 1.0 ) for the Ti3 layer. It is a MAX phase ceramic powder having a composition. Further, 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 least 0.01. 0.02 can be adopted as the lower limit. More preferably, the upper limit is adjusted to 0.05. 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.
  • 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).
  • a multi-layer with a size of several micrometers having a void layer that constitutes a particle material by removing part of Al by acid-treating MAX phase ceramic powder (A element is Al), which is a layered compound.
  • a layered compound 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.
  • KF, LiF, etc. hydrofluoric acid salt
  • 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 20°C to 30°C. 20°C to 25°C is more preferred.
  • the electrode material of the present embodiment is a material that can be suitably used for secondary batteries.
  • Li ions and Na ions can be intercalated and detached between layers, it can be suitably used as an electrode active material. Moreover, it can also be used as a conductive aid because of its conductivity. Effective for lithium secondary batteries and sodium secondary batteries. Lithium ions and sodium ions are stored and desorbed in the void layer from which the Al layer has been removed by acid treatment.
  • the electrode has an active material layer containing an active material made of the composite particle material of the present embodiment, and a current collector made of a thin metal plate or the like and having an active material layer made of the active material formed on the surface thereof.
  • a binder may be included to form the active material layer.
  • the active material layer can contain an active material other than the composite particle material of the present embodiment, a conductive auxiliary agent, and the like, if necessary.
  • a commonly used binder such as carboxymethyl cellulose, polyvinylidene fluoride, styrene-butadiene rubber, polyvinylpyrrolidone, polyvinyl alcohol, or any other binder that can be used can be used.
  • Acetylene black, ketschen black, carbon nanotube, graphene, carbon fiber, graphite powder, hard carbon powder and the like can be used as the conductive auxiliary agent.
  • Example 1 ⁇ Pretreatment process TiC powder (TI-30-10-0020, Rare Metallic) 12.3 g, Ti powder (TIE07PB 3N, Kojundo Chemical) 4.9 g, Al powder (ALE15PB 3NG, Kojundo Chemical) 2.8 g was 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 sintered in an Ar stream at 1450° C. for 2 hours to obtain Ti 3 AlC 2 as MAX phase ceramics.
  • the resulting Ti 3 AlC 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 AlC 2 powder pulverized to about 3 ⁇ m.
  • the raw material suspension was adjusted by measuring the particle concentration and adding water so that the particle concentration of Ti 3 Al 0.02 C 2 MXene was 15.6 mg/mL.
  • 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.
  • a powder of Ti 3 AlC 2 which is a MAX phase ceramic, was subjected to XRD measurement, and its profile is shown in FIG. The peeled substance was measured for zeta potential in water at pH 7.0 and found to be -28.9 mV.
  • ⁇ Acid treatment process As a method for acid treatment of acetylene black as fine carbon particles, 100 parts by mass of a mixed acid in which sulfuric acid (98% by mass) and nitric acid (68% by mass) are mixed at a volume ratio of 3:1 is mixed with 1 part of acetylene black. 0 mass part was added, and the mixture was immersed for 10 minutes in an environment of 85°C. Then, it was washed with water until the pH reached about 6.0, and then the water was replaced with IPA. It was air-dried at room temperature to obtain a hydrophilic acid-treated acetylene black powder. FTIR analysis detected a COOH group and a CO group as surface functional groups.
  • the measured zeta potential at pH 7.0 in water was -22.5 mV.
  • the acid-treated acetylene black was deagglomerated with a shaker under conditions of 140 rpm, amplitude of 45 mm, and 24 hours to prepare a hydrophilic acetylene black aqueous slurry.
  • a hydrophilic acetylene black aqueous slurry was dropped onto a hydrophilized Si wafer and observed with an SEM. 100 primary particles were arbitrarily observed, the vertical and horizontal dimensions were measured, and the average primary particle diameter is shown in Table 1.
  • an aqueous solution prepared by dissolving 3.5 g of lithium hydroxide in 30 mL of pure water was completely dissolved with a shaker at 140 rpm for 1 hour and an amplitude of 45 mm. and an amplitude of 45 mm for 1 hour.
  • wash with water once, replace with ethanol three times stir with a shaker for 6 hours under conditions of 140 rpm in ethanol to loosen coarse aggregates, and obtain a particle concentration of 5.0 mg / mL.
  • An ethanol slurry of aggregates was obtained.
  • Water washing and ethanol replacement were carried out by adding water or ethanol, centrifuging at 1000 to 8000 G for 10 minutes to sediment aggregates, and removing the supernatant.
  • the content of ethanol as alcohol in the resulting alcohol slurry was 99% based on the mass of the entire dispersion medium.
  • an alcohol slurry of the composite aggregated particle material was spray-dried to prepare granules.
  • the operating conditions were a disk rotation speed of 20,000 rpm, a nitrogen atmosphere, an alcohol slurry injection temperature of 80° C., and an alcohol slurry injection rate of 1.4 kg/hour.
  • the SEM photograph (Fig. 4) of the obtained composite powder is shown.
  • the resulting composite particle material has a high degree of sphericity, and when enlarged, maintains a 3D porous aggregation structure with extremely thin MXene nanosheets in which acetylene black is uniformly dispersed, and has a high specific surface area. I found out.
  • 100 secondary particles were similarly observed with an SEM, they were all composite particle materials having the same porous microstructure. In other words, it became clear that the microstructure was not disturbed by external stress.
  • Table 2 shows the average secondary particle diameter and sphericity of the secondary particles
  • Table 3 shows the specific surface area, average pore diameter, average pore volume and bulk density.
  • FIG. 5 shows nitrogen adsorption isotherms.
  • 100 particles were arbitrarily extracted from the SEM image, and the secondary particle diameter was calculated as (long side + short side)/2, and the average was calculated as the average diameter.
  • 100 particles were sampled and the short side/long side were measured, and the average was calculated as the sphericity.
  • the upper limit is 1.0, and the closer to 1.0, the higher the sphericity.
  • the bulk density of secondary particles was measured according to JIS1628-1997.
  • the specific surface area, average pore diameter, and average pore volume were measured by the BET method immediately after heating at 110°C for 6 hours in vacuum.
  • the degree of interdispersion which is the degree of dispersion of the primary particles of each of the Ti 3 Al 0.02 C 2 MXene nanosheets and acetylene black as fine carbon particles, was measured. Specifically, it was quantified by Raman spectroscopic analysis. 100 points were analyzed in the laser intensity range from 100 cm ⁇ 1 to 2000 cm ⁇ 1 at a laser intensity at which anatase does not precipitate, and the standard deviation of the B peak intensity/A peak intensity ratio was calculated as the interdispersion degree. Table 4 shows the interdispersion index obtained.
  • the obtained composite particle material was heat-treated in vacuum at 110° C. for 5 hours, and the change in mass was measured. Furthermore, the obtained composite particle material was subjected to XRD measurement, and the profile is shown in FIG. Table 6 shows the interlayer distance of the (002) plane of MXene nanosheets from the results of XRD measurement.
  • the resulting composite particle material was uniaxially pressed in a ⁇ 10 mm mold at a pressure of 0.5 kg/cm 2 and then subjected to cold isostatic pressing (CIP) at a pressure of 1.0 ton/cm 2 .
  • Table 7 shows the electrical resistance of the surface of the powder measured by the four-probe method using a copper wire of ⁇ 0.1 mm.
  • Example 2 Using a graphite resistance furnace, the uniformly mixed dry powder was placed in an alumina crucible and fired under the conditions of 1430° C. for 2 hours in an Ar stream to obtain Ti 3 AlC 2 as MAX phase ceramics. to obtain a composite particle material. Measurements were taken in the same manner as in Example 1, and the results are shown in the figure and table.
  • An AFM image of the exfoliated MXene nanosheet is shown in FIG. 6, and an SEM image is shown in FIG.
  • FIG. 8 shows the XRD profile of the MAX phase ceramics and the composite particle material
  • FIG. 9 shows the SEM image.
  • Table 1 shows the average thickness and size of the exfoliated MXene nanosheets
  • Table 2 shows the average particle diameter and sphericity of the resulting composite particle material
  • Table 2 shows the specific surface area, average pore diameter, average pore volume, and bulk density.
  • Table 4 shows the degree of interdispersion
  • Table 5 shows the change in mass
  • Table 6 shows the interlayer distance of the (002) plane of MXene nanosheets
  • Table 7 shows the surface electrical resistance.
  • Example 3 A composite particle material of MXene and acid-treated acetylene black was produced in the same manner as in Example 2, except that the amount of acid-treated acetylene black added was 10% by mass based on the mass of Ti 3 Al 0.02 C 2 MXene nanosheets.
  • Table 2 shows the average particle diameter and sphericity of the obtained composite particle material, which were measured in the same manner as in Example 1.
  • Table 3 shows the specific surface area, average pore diameter, average pore volume, and bulk density.
  • Table 4 shows the degree of dispersion, Table 5 shows the change in mass, Table 6 shows the interlayer distance of the (002) plane of MXene nanosheets, and Table 7 shows the surface electrical resistance.
  • Example 4 A composite particle material of MXene and acid-treated acetylene black was produced in the same manner as in Example 2, except that the amount of acid-treated acetylene black added was 3% by mass based on the mass of the Ti 3 Al 0.02 C 2 MXene nanosheets.
  • Table 2 shows the average particle diameter and sphericity of the obtained composite particle material, which were measured in the same manner as in Example 1.
  • Table 3 shows the specific surface area, average pore diameter, average pore volume, and bulk density.
  • Table 4 shows the degree of dispersion
  • Table 5 shows the change in mass
  • Table 6 shows the interlayer distance of the (002) plane of the MXene nanosheet
  • Table 7 shows the surface electrical resistance.
  • Example 5 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.
  • Ti 3 Al(C 0.75 N 0.25 ) 2 powder was prepared in the same manner as in Example 1 using 9 g of Al powder (ALE15PB 3NG, Kojundo Chemical) and 2.8 g of Al powder (ALE15PB 3NG, Kojundo Chemical) as starting materials. It was confirmed by XRD analysis that the powder was MAX phase ceramic powder free of impurities. Using this, a composite particle material was prepared in the same manner as in Example 1.
  • Table 2 shows the average particle diameter and sphericity of the obtained composite particle material, which were measured in the same manner as in Example 1.
  • Table 3 shows the specific surface area, average pore diameter, average pore volume, and bulk density.
  • Table 4 shows the degree of dispersion,
  • Table 5 shows the change in mass, and
  • Table 6 shows the interlayer distance of the (002) plane of the MXene nanosheets.
  • Example 1 A composite particle material of MXene and acid-treated acetylene black was produced in the same manner as in Example 2, except that the amount of acid-treated acetylene black added was 2% by mass based on the mass of Ti 3 Al 0.02 C 2 MXene nanosheets.
  • Table 2 shows the average particle diameter and sphericity of the obtained composite particle material, which were measured in the same manner as in Example 1.
  • Table 3 shows the specific surface area, average pore diameter, average pore volume, and bulk density.
  • Table 4 shows the degree of dispersion, Table 5 shows the change in mass, and Table 6 shows the interlayer distance of the (002) plane of the MXene nanosheets.
  • Example 2 An ethanol slurry of the composite aggregated particle material was prepared in the same manner as in Example 2 up to the mixing step and the aggregation step. In order to further reduce the amount of water remaining in the solvent, ethanol was replaced with IPA to prepare an IPA slurry of the composite aggregated particle material.
  • the IPA slurry was subjected to centrifugal sedimentation (7900 G), and the sediment was air-dried for 12 hours at room temperature. After that, heat treatment was performed at 60° C. for 6 hours in vacuum to obtain a mass of composite agglomerated particle material. After that, it was pulverized by applying physical stress with a grinder composed of a mortar and a pestle to produce the composite particulate material of this comparative example. The same operations as in Example 1 were performed for other steps.
  • Example 2 Measured in the same manner as in Example 1, the average particle diameter and sphericity of the obtained composite particle material are shown in Table 2, the specific surface area, average pore diameter, average pore volume, and bulk density are shown in Table 3, and the degree of interdispersion are shown in Table 4, the mass change in Table 5, the interlayer distance of the (002) plane of the MXene nanosheet in Table 6, and the surface electrical resistance in Table 7. Furthermore, 100 secondary particles were observed with an SEM to examine the uniformity of the fine structure when pulverized by applying physical stress. Most of the secondary particles maintained the aggregation structure, but the aggregation structure was destroyed in some secondary particles (Fig. 10).
  • Example 3 A stripped material suspension was obtained in the same manner as in Example 1 up to the stripping step.
  • An aqueous solution of 3.5 g of lithium hydroxide dissolved in 40 mL of pure water was added to 220 mL of the exfoliated material suspension having a particle concentration of 15.6 mg/mL obtained in the exfoliation step in advance for 1 hour with a shaker at 140 rpm and an amplitude of 45 mm.
  • a completely dissolved alkaline aqueous solution was added under the conditions and stirred for 1 hour with a shaker at 140 rpm and an amplitude of 45 mm.
  • a paste was prepared by adding 5% acid-treated acetylene black and N-methylpyrrolidone (NMP) to the prepared secondary particles based on the mass of MXene.
  • Paste preparation was performed with a grinder consisting of a mortar and pestle. After that, it was dried in vacuum at 110° C. for 6 hours to remove NMP, thereby producing a composite particle material of MXene and acetylene black. The same operations as in Comparative Example 2 were performed for other steps.
  • the average particle diameter and sphericity of the composite particle material obtained by measurement in the same manner as in Example 1 are shown in Table 2, the specific surface area, average pore diameter, average pore volume, and bulk density are shown in Table 3, and the interdispersion degree is shown in Table 3.
  • Table 4 shows the change in mass, and Table 6 shows the interlayer distance of the (002) plane.
  • Example 4 220 mL of exfoliated material suspension was obtained in the same manner as in Example 1 up to the exfoliation step. 220 mL of IPA was added to create an MXene aggregate particle slurry in a mixed solution of IPA and water. This was centrifuged (7900 G) and the sediment was air-dried at room temperature for 12 hours. After that, it was dried in vacuum at 60° C. for 6 hours to obtain an aggregate mass. After that, a crusher composed of a mortar and a pestle was used to apply physical stress to crush the powder to produce secondary particles.
  • a paste was prepared by adding N-methylpyrrolidone (NMP) dispersed with 5% acid-treated acetylene black based on the mass of MXene to the prepared secondary particles.
  • the paste was made using a grinder consisting of a mortar and pestle. Thereafter, NMP was removed at 110° C. for 6 hours in vacuum to produce a composite particle material of MXene and acetylene black.
  • NMP N-methylpyrrolidone
  • the average particle diameter and sphericity of the obtained composite particle material were measured in the same manner as in Example 1.
  • Table 2 shows the specific surface area, average pore diameter, average pore volume, and bulk density. The lines are shown in FIG.
  • FIGS. 4 and 9 the composition of Ti 3 Al 0.02 C 2 MXene (97.0-90.0% by mass)/carbon particles (3.0-10.0% by mass) and Ti 3 Al 0.02 ( C 0.75 N 0.25 ) 2 MXene (95% by mass)/carbon microparticles (5.0% by mass)
  • the composite powder material spray-dried from an alcohol slurry of agglomerated powder has a spherical shape with an average secondary particle size of approximately single micrometer. Excellent degree. High-magnification SEM observation of 100 secondary particles showed the 3D porous structure shown in FIGS. 4 and 9 as representative examples. On the other hand, when a lump of agglomerated powder is air-dried and vacuum-dried at 60° C.
  • Table 3 shows the physical values of the 3D porous structure.
  • the composite powder material obtained by spray-drying the agglomerated powder alcohol slurry has a higher specific surface area than the composite particle material obtained by pulverizing the agglomerates by applying physical stress. Average pore diameter and average pore volume increase. This is because the droplets of the agglomerated powder alcohol slurry are dried instantly, so shrinkage during drying is suppressed.
  • MXene is peeled off to a monolayer level, specifically a thickness of 1.5 nm.
  • Shrinkage during drying means that the MXene nanosheets adhere to each other, and obtaining a composite powder material without shrinkage indicates that the composite powder material is produced while maintaining the MXene nanosheets at the monolayer level. Smooth ion diffusion leads to rapid charging and discharging, excellent cycle characteristics, and high capacity.
  • Example 2 has a larger specific surface area.
  • the sintering (synthesis) temperature of MAX phase ceramics is lowered within a range that does not produce impurities, the bonding force between the layers decreases, and the average size decreases while maintaining the thickness at the monolayer level in the exfoliation process.
  • a smaller average size of about 0.2 ⁇ m (Example 2) had a larger specific surface area, a smaller average pore diameter, and a larger pore volume than about 0.8 ⁇ m (Example 1).
  • the adsorption isotherms of Examples 1, 2 and Comparative Example 4 are shown in FIG. 5 as typical examples. It can be seen that the composite particulate material of the present invention is an excellent 3D porous material.
  • Table 5 shows the change in mass when 0.3 g of the composite powder material was evenly spread on a dish of 20 cm 3 or more and heated in vacuum at 110° C. for 5 hours.
  • the composite powder material is prepared by spray-drying the agglomerated powder alcohol slurry. Residual water is completely removed.
  • Table 3 shows the bulk density of the obtained composite particle material.
  • a composite powder material obtained by spray-drying an alcohol slurry of agglomerated powder having a composition of (% by mass)/carbon particles (5.0% by mass) was compared with a composite particulate material obtained by pulverizing agglomerates by applying physical stress.
  • the former has a 3D porous aggregate structure, has a uniform secondary particle size, and is characterized by having a spherical shape. However, there is a feature of continuous particle blending. For this reason, the former has a smaller bulk density.
  • the former makes it possible to improve the performance of the produced secondary batteries, etc., because the produced membrane has a uniform structure.
  • composite particle materials having several types of secondary particle diameters are prepared so that they are properly packed, and a distribution rule that creates the closest packing using the Andreasen equation has been proposed. It is preferable to perform particle blending, or to perform two-stage particle blending in which two types of composite particle materials, coarse particles and fine particles, are blended.
  • Table 6 shows the interlayer distance of the (002) plane of MXene obtained by XRD of the obtained composite particle material.
  • the composite particle material of the present invention in which the carbon particles are uniformly arranged has a larger interlayer distance than the process in which the carbon particles are mixed by adding NMP after producing the aggregated powder using only MXene. This is because Li and/or Na ions and chloride ions are intercalated between the layers of MXene in the process of uniformly arranging the carbon particles, and the layers are expanded.
  • the numerical value obtained by subtracting the interlayer distance of the (002) plane of MAX phase ceramics from the (002) plane of MXene can be considered as the distance of the gap generated after removing the Al phase of MAX phase ceramics (see FIG. 11).
  • the composite particle material of the present invention will be about 0.6 nm.
  • ions larger than Li ions such as Na ions, can also be intercalated and deintercalated.
  • the gap is large, there are advantages such as rapid charge/discharge and long life.
  • Table 7 shows the surface electrical resistance of the compact. This was done to define the oxidation state of the MXene nanosheet surface and the amount of water remaining between the layers. Oxidation of the surface of MXene nanosheets increases electrical resistance. In addition, if there is water remaining between the layers, it will change over time, oxidizing the surfaces of the layers and increasing the surface electrical resistance. Therefore, if the oxidation progresses or if the amount of moisture between the layers is large, the electrical resistance of the surface increases.
  • the surface electrical resistance of the compact also affects the number of contacts between powders.
  • the number of contacts is indicated by the relative density of the compact. Relative density is determined by (bulk specific gravity/true specific gravity) x 100.
  • the composite particle material used for the negative electrode active material of the secondary battery and the electrode of the electrochemical capacitor preferably has a surface electrical resistance of 1.0 to 100.0 ⁇ / ⁇ .
  • the original composite particle material is an ideal two-component material that has excellent ion diffusibility and allows electrons to move smoothly to the current collector. Since it is a composite particle material suitable for the negative electrode active material of the secondary battery (storage battery) or suitable for the positive electrode and / or negative electrode active material of the ideal pseudocapacitor, the 3D porous aggregation structure can be maintained, so that the ion diffusion is further improved. It is expected that the degree of sphericity will be increased, and since the degree of sphericity can be increased, it is expected that the uniformity of the film will be improved.
  • Example 1 when a composite particle material was produced using methanol or isopropanol instead of ethanol in Example 1, a composite particle material similar to that of Example 1 was obtained.
  • the composite particulate material was produced using isopropanol instead of ethanol in Example 1, it was necessary to raise the spray temperature in the granulation process to 85°C.
  • the surface electric resistance in the same manner as in Example 1, it was 60.5 ⁇ / ⁇ , and when ethanol was used, it was 41.1 ⁇ / ⁇ , but the resistance increased slightly. This is because the surface was slightly oxidized because the spray temperature was raised slightly.
  • the composite particulate material was produced using methanol instead of ethanol in Example 1, the spray temperature in the granulation process could be lowered to 75°C.
  • the solvent used in the granulation step may be ethanol, methanol, or isopropyl alcohol.

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Abstract

La présente invention concerne un nouveau matériau particulaire composite d'une nanofeuille de Mxène et d'un microcorps de carbone.　Un matériau particulaire composite selon la présente invention comprend 90 à 97 parties en masse d'un Mxène en forme de feuille de Ti3Ala(C(1.0-x)Nx)2 (0 ≤ x ≤ 0.25 et a est supérieur ou égal à 0,01) et 3 à 10 parties en masse d'un microcorps de carbone, tout en ayant une interdispersibilité de 0,01 à 7,00 et une surface spécifique supérieure ou égale à 75 m2/g. La nanofeuille de Mxène a une épaisseur moyenne comprise entre 1,0 et 3,5 nm. De plus, la sphéricité est supérieure ou égale à 0,8. Un procédé de production de ce matériau particulaire composite selon la présente invention comprend une étape de granulation d'une suspension alcoolique, qui contient des agrégats formés du Mxène et du microcorps, au moyen d'un procédé de séchage par pulvérisation.
PCT/JP2021/042466 2021-11-18 2021-11-18 Matériau particulaire composite, son procédé de production et électrode WO2023089739A1 (fr)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2020136865A1 (fr) * 2018-12-28 2020-07-02 株式会社アドマテックス Matériaux particulaires de mxène, procédé de production de ces matériaux particulaires et batterie secondaire
WO2020136864A1 (fr) * 2018-12-28 2020-07-02 株式会社アドマテックス Matériau particulaire de mxène, suspension, batterie secondaire, électrode transparente, et procédé de production d'un matériau sous forme de particules de mxène
CN112263974A (zh) * 2020-11-24 2021-01-26 山东大学 一种喷雾干燥法制备Ti3C2Tx/炭黑复合微球的方法
CN113235108A (zh) * 2021-04-30 2021-08-10 武汉理工大学 一种MXene负载贵金属团簇催化剂及其制备方法和应用

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2020136865A1 (fr) * 2018-12-28 2020-07-02 株式会社アドマテックス Matériaux particulaires de mxène, procédé de production de ces matériaux particulaires et batterie secondaire
WO2020136864A1 (fr) * 2018-12-28 2020-07-02 株式会社アドマテックス Matériau particulaire de mxène, suspension, batterie secondaire, électrode transparente, et procédé de production d'un matériau sous forme de particules de mxène
CN112263974A (zh) * 2020-11-24 2021-01-26 山东大学 一种喷雾干燥法制备Ti3C2Tx/炭黑复合微球的方法
CN113235108A (zh) * 2021-04-30 2021-08-10 武汉理工大学 一种MXene负载贵金属团簇催化剂及其制备方法和应用

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