WO2023162423A1 - Two-dimensional particle, method for producing two-dimensional particle, and material - Google Patents

Two-dimensional particle, method for producing two-dimensional particle, and material Download PDF

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WO2023162423A1
WO2023162423A1 PCT/JP2022/046436 JP2022046436W WO2023162423A1 WO 2023162423 A1 WO2023162423 A1 WO 2023162423A1 JP 2022046436 W JP2022046436 W JP 2022046436W WO 2023162423 A1 WO2023162423 A1 WO 2023162423A1
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component
less
dimensional
particles
atom
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French (fr)
Japanese (ja)
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直 岡田
章麿 ▲柳▼町
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株式会社村田製作所
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    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B32/00—Carbon; Compounds thereof
    • C01B32/90—Carbides
    • C01B32/914—Carbides of single elements
    • C01B32/921—Titanium carbide

Definitions

  • the present disclosure relates to two-dimensional particles, methods for producing two-dimensional particles, and materials.
  • MXene has attracted attention as a new material.
  • MXene is a type of so-called two-dimensional material, which is a layered material having the form of one or more layers, as described below.
  • MXenes generally have the form of particles (which can include powders, flakes, nanosheets, etc.) of such layered materials.
  • Non-Patent Document 1 uses a mixture of HF and an inorganic acid with anions larger than F as an etchant, and such anions facilitate intercalation and deintercalation of water, resulting in clay-like swelling of MXene. It is stated to bring
  • Non-Patent Document 1 merely describes washing with a metal salt aqueous solution having a concentration of 1 mol/L, and does not provide any further investigation.
  • the MXene described in Non-Patent Document 1 was not sufficiently satisfactory in moisture resistance.
  • An object of the present disclosure is to provide two-dimensional particles capable of realizing a material having moisture resistance.
  • the present disclosure also aims to provide a method for producing such two-dimensional particles and a material containing such two-dimensional particles.
  • the layer has the following formula: M m X n (wherein M is at least one Group 3, 4, 5, 6, 7 metal; X is a carbon atom, a nitrogen atom, or a combination thereof; n is 1 or more and 4 or less, m is greater than n and less than or equal to 5) and a modification or termination T (T is at least one selected from the group consisting of a hydroxyl group, a fluorine atom, a chlorine atom, an oxygen atom and a hydrogen atom) present on the surface of the layer body represented by and Li atoms include a first component and a second component having a larger chemical shift as measured by 7 Li NMR than the first component, Two-dimensional particles, wherein the proportion of the first component in the total of the first component and the second component is 55 atomic % or more.
  • M is at least one Group 3, 4, 5, 6, 7 metal; X is a carbon atom, a nitrogen atom, or a combination thereof; A is at least one Group 12, 13, 14, 15, 16 element; n is 1 or more and 4 or less, m is greater than n and less than or equal to 5) preparing a precursor represented by (b) using an etchant to etch away at least a portion of the A atoms from the precursor to obtain an etched product; (c) using a metal-containing compound containing metal ions to intercalate the etched product in a dispersion medium to obtain an intercalated product; (d) subjecting the intercalated product to a delamination treatment to obtain two-dimensional particles; The etchant contains HF and HI, The metal-containing compound comprises a Li salt, The method for producing two-dimensional particles, wherein the dispersion medium has a pH of 0.6 or more and 1.8 or less.
  • the two-dimensional particles contain Li atoms,
  • the Li atoms include a first component and a second component having a larger chemical shift as measured by 7 Li NMR than the first component,
  • the material according to [6] which further contains a resin.
  • the present disclosure it is possible to provide two-dimensional particles capable of realizing a material having moisture resistance.
  • the present disclosure may also provide methods of making such two-dimensional particles and materials comprising such two-dimensional particles.
  • FIG. 1 is a schematic cross-sectional view showing MXene particles of a layered material in one embodiment of the present disclosure, where (a) shows a monolayer MXene particle and (b) shows a multi-layer (illustratively bi-layer) MXene particle; . 1 is a schematic cross-sectional view showing materials in one embodiment of the present disclosure; FIG.
  • a two-dimensional particle in this embodiment is a two-dimensional particle of a layered material having one or more layers and contains Li atoms and I atoms.
  • the above layer has the following formula: M m X n (wherein M is at least one Group 3, 4, 5, 6, 7 metal; X is a carbon atom, a nitrogen atom, or a combination thereof; n is 1 or more and 4 or less, m is greater than n and less than or equal to 5) (the layer body may have a crystal lattice in which each X is located in an octahedral array of M) and a surface of the layer body (more particularly, the surfaces of the layer bodies facing each other a modification or termination T (T is at least one selected from the group consisting of hydroxyl groups, fluorine atoms, chlorine atoms, oxygen atoms and hydrogen atoms) present on at least one of the two surfaces that Li atoms include a first component and a second component having a larger chemical shift than the first component as measured by 7 Li NMR (nuclear magnetic resonance), The ratio of the first component to the total of the first component and the second component is 55 atomic % or more.
  • the first component of Li atoms is the less mobile component and the second component is the less mobile component. Since the Li atoms of the first component have low mobility, it is considered that they are difficult to diffuse in the two-dimensional particles and to attract water from the outside of the two-dimensional particles.
  • the I atom has a lower ionization energy and a higher electron affinity than other halogen atoms (F atom, Cl atom, and Br atom), and thus is considered to be easily oxidized.
  • the I atoms when I atoms are included, the I atoms are preferentially oxidized, and the oxidation of the two-dimensional particles is suppressed. Under the condition that the first component contained in the Li atoms in the two-dimensional particles is larger than the second component, the coexistence of the I atoms is thought to improve the moisture resistance of the two-dimensional particles.
  • moisture resistance can be evaluated by maintaining conductivity even when placed under high humidity conditions for a long time.
  • electrodes comprising such materials can be used in applications requiring high moisture resistance, for example electrodes for antennas, in particular electrodes for RFID (radio frequency identifier).
  • the use of the electrode is not limited to this.
  • the oxidation number of the element is not limited to 0, and may be any number within the range of possible oxidation numbers of the element.
  • the layered material may be understood as a layered compound, also denoted as "M m X n T s ", where s is any number, conventionally x or z may be used instead of s.
  • n can be 1, 2, 3 or 4, but is not so limited.
  • M is preferably at least one selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo and Mn, and from Ti, V, Cr and Mo At least one selected from the group consisting of is more preferable.
  • M can be titanium or vanadium and X can be a carbon or nitrogen atom.
  • MAX phase is Ti 3 AlC 2 and MXene is Ti 3 C 2 T s (in other words, M is Ti, X is C, n is 2, m is 3 is).
  • MXene may contain A atoms derived from the MAX phase of the precursor in a relatively small amount, for example, 10% by mass or less relative to the original A atoms.
  • the residual amount of A atoms can be preferably 8% by mass or less, more preferably 6% by mass or less. However, even if the residual amount of A atoms exceeds 10% by mass, there may be no problem depending on the application and usage conditions of the two-dimensional particles.
  • the layer may be referred to as an MXene layer, and the two-dimensional particles may be referred to as MXene two-dimensional particles or MXene particles.
  • the two-dimensional particles of the present embodiment are aggregates containing one layer of MXene particles (hereinafter simply referred to as "MXene particles") 10a (single-layer MXene particles) schematically illustrated in FIG. 1(a).
  • MXene particles 10a include a layer body (M m X n layer) 1a represented by M m X n and a surface of the layer body 1a (more specifically, two surfaces facing each other in each layer). (at least one of) is the MXene layer 7a with modifications or terminations T3a, 5a present in the . Therefore, the MXene layer 7a is also expressed as "M m X n T s ", where s is any number.
  • the two-dimensional particles of this embodiment may contain one or more layers.
  • multiple layers of MXene particles include two layers of MXene particles 10b as schematically shown in FIG. 1(b), but are not limited to these examples.
  • 1b, 3b, 5b and 7b in FIG. 1(b) are the same as 1a, 3a, 5a and 7a in FIG. 1(a) described above.
  • Two adjacent MXene layers (eg 7a and 7b) of a multi-layered MXene particle are not necessarily completely separated and may be in partial contact.
  • the above-mentioned MXene particles 10a are those in which the above-mentioned multi-layered MXene particles 10b are individually separated and exist in one layer. may be a mixture of
  • the thickness of each layer (corresponding to the MXene layers 7a and 7b described above) contained in the MXene particles is, for example, 0.8 nm or more and 5 nm or less, particularly 0.8 nm or more and 3 nm or less. Yes (mainly depending on the number of M atomic layers included in each layer).
  • the interlayer distance or pore size, indicated by ⁇ d in FIG. 1(b) is for example 0.8 nm or more and 10 nm or less, especially 0.8 nm or more and 5 nm or less. , more particularly about 1 nm, and the total number of layers can be greater than or equal to 2 and less than or equal to 20,000.
  • the multilayered MXene particles that can be contained are preferably MXene particles with a small number of layers obtained through a delamination process.
  • the phrase “the number of layers is small” means, for example, that the number of MXene layers to be stacked is 6 or less.
  • the thickness of the multi-layered MXene particles having a small number of layers in the stacking direction is preferably 15 nm or less, more preferably 10 nm or less.
  • this "multilayer MXene particle with a small number of layers” may be referred to as "small layer MXene particle”.
  • single-layer MXene particles and low-layer MXene particles are sometimes collectively referred to as "single-layer/low-layer MXene particles.”
  • the two-dimensional particles of the present embodiment preferably include single-layer MXene particles and low-layer MXene particles, ie, single-layer/low-layer MXene particles.
  • the ratio of single-layer/small-layer MXene particles having a thickness of 15 nm or less is preferably 90% by volume or more, more preferably 95% by volume or more.
  • the Li atoms include a first component and a second component having a larger chemical shift than the first component as measured by 7 Li NMR, and the first component in the sum of the first component and the second component is 55 atomic % or more. Thereby, a material having moisture resistance can be realized.
  • the ratio of the first component in the total of the first component and the second component may be 55 atomic % or more and 70 atomic % or less, and particularly 56 atomic % or more and 65 atomic % or less.
  • the proportion of the first component in the sum of the first component and the second component can be measured by 7 Li NMR.
  • 7 Li NMR the proportion of the first component in the total
  • the integration delay time for the 7 Li NMR measurement is 4 seconds.
  • the first component is the low motile component and the second component is the high motile component. Since the Li atoms of the first component have low mobility, it is considered that they are difficult to diffuse in the two-dimensional particles and to attract water from the outside of the two-dimensional particles. It is believed that by coexisting the first component and the second component in a specific abundance ratio, it is possible to prevent adsorption of moisture while achieving a single layer and a small number of layers, and to exhibit high moisture resistance. .
  • the mobility of the first component and the second component may be confirmed, for example, by comparing T2 relaxation times (spin-spin relaxation times). Without being bound by theory, it is believed that the T2 relaxation time is related to the motility of each component, with lower motility resulting in shorter T2 relaxation times.
  • the chemical shift of the first component as measured by 7 Li NMR can be, for example, 1.1 ppm or less, even 0 ppm or more and 1.1 ppm or less, especially 0 ppm or more and 1.05 ppm or less.
  • the chemical shift of the second component measured by 7 Li NMR can be, for example, greater than 1.1 ppm, even greater than 1.1 ppm and 2.0 ppm or less, especially 1.15 ppm or more and 1.8 ppm or less.
  • the reference material for 7 Li NMR measurement is Li in a 1 mol/L LiCl aqueous solution.
  • the chemical shift of the first component measured by 7 Li NMR represents the chemical shift value of the peak assigned to the first component in the 7 Li NMR spectrum.
  • the chemical shift of the second component measured by 7 Li NMR represents the chemical shift value of the peak assigned to the second component in the 7 Li NMR spectrum.
  • the chemical shift of the second component is larger than the chemical shift of the first component measured by 7 Li NMR, and the peak attributed to the second component is relative to the peak attributed to the first component by 7 Li NMR Located on the low-field side of the spectrum.
  • the peaks may be separated by regression using the Lorenz curve.
  • the Li atoms are typically present on the layer. That is, it may be in contact with the layer or may exist on the layer via another element.
  • the content of Li atoms in the two-dimensional particles is, for example, 0.1% by mass or more and 20% by mass or less, further 0.1% by mass or more and 10% by mass or less, especially 0.2% by mass or more and 3% by mass or less, especially It may be 0.2% by mass or more and 0.5% by mass or less.
  • the Li atom content can be measured by, for example, inductively coupled plasma atomic emission spectrometry (ICP-AES).
  • ICP-AES inductively coupled plasma atomic emission spectrometry
  • the I atom is typically present on the layer. That is, it may be in contact with the layer or may exist on the layer via another element.
  • the content of I atoms in the two-dimensional particles is, for example, 0.2% by mass or more and 1.5% by mass or less, further 0.3% by mass or more and 1.2% by mass or less, particularly 0.4% by mass or more and 1.5% by mass or less. It may be 1% by mass or less.
  • the moisture resistance of the two-dimensional particles can be improved.
  • the two-dimensional particles of the present disclosure preferably have a low content of Cl atoms and Br atoms.
  • the content of Cl atoms in the two-dimensional particles can be, for example, 0 ppm or more and 900 ppm or less, further 0 ppm or more and 500 ppm or less, and particularly 0 ppm or more and 100 ppm or less, based on mass.
  • the content of Br atoms in the two-dimensional particles can be, for example, 0 ppm or more and 900 ppm or less, further 0 ppm or more and 500 ppm or less, and particularly 0 ppm or more and 100 ppm or less, on a mass basis.
  • the total content of Cl atoms and Br atoms in the two-dimensional particles can be, for example, 1,500 ppm or less, further 500 ppm or less, and particularly 100 ppm or less on a mass basis. Since the content of Cl atoms and Br atoms in the two-dimensional particles is within the above range, it can be suitably used for applications requiring a low content of Cl atoms and Br atoms (so-called "halogen-free applications"). .
  • the concentration of Cl atoms, Br atoms and I atoms in two-dimensional particles can be measured by combustion ion chromatography.
  • the ratio of (average length of two-dimensional surface of two-dimensional particles)/(average thickness of two-dimensional particles) is 1.2 or more, preferably 1.5 or more, more preferably 2 That's it.
  • the average major diameter of the two-dimensional surfaces of the two-dimensional particles and the average thickness of the two-dimensional particles may be obtained by the method described later.
  • the average value of the long diameters of the two-dimensional surfaces is 1 ⁇ m or more and 20 ⁇ m or less.
  • the average value of the major diameters of the two-dimensional surfaces may be referred to as "average flake size”.
  • the orientation of the two-dimensional particles can be evaluated, for example, by the electrical conductivity of the material containing the two-dimensional particles. Since the two-dimensional particles of the present embodiment have a large average flake size of 1.0 ⁇ m or more, a film formed using these two-dimensional particles, for example, a film obtained by stacking these two-dimensional particles, A conductivity of 000 S/cm or more can be achieved.
  • the average value of the long axis of the two-dimensional surface is preferably 1.5 ⁇ m or more, more preferably 2.5 ⁇ m or more.
  • MXene When the delamination treatment of MXene is performed by subjecting MXene to ultrasonic treatment, most of MXene is reduced in major diameter to about several hundred nm by ultrasonic treatment. It is believed that the films formed with MXene have poor orientation of the two-dimensional particles, and the electrical conductivity of materials containing such two-dimensional particles is low.
  • the average value of the major axis of the two-dimensional surface is 20 ⁇ m or less, preferably 15 ⁇ m or less, and more preferably 10 ⁇ m or less.
  • the major axis of the two-dimensional surface refers to the major axis of each MXene particle approximated to an elliptical shape in an electron micrograph, and the average value of the major axis of the two-dimensional surface is 80 particles or more. The number average of the above major diameters. Scanning electron microscope (SEM) and transmission electron microscope (TEM) photographs can be used as electron microscopes.
  • the average value of the major diameters of the two-dimensional particles of the present embodiment may be measured by dissolving a material containing the two-dimensional particles in a solvent and dispersing the two-dimensional particles in the solvent. Alternatively, it may be measured from an SEM image of the material.
  • the average thickness of the two-dimensional particles of the present embodiment is preferably 1 nm or more and 15 nm or less.
  • the thickness is preferably 10 nm or less, more preferably 7 nm or less, and even more preferably 5 nm or less.
  • the lower limit of the thickness of two-dimensional particles can be 1 nm.
  • the average value of the thickness of the two-dimensional particles is obtained as a number average dimension (for example, number average of at least 40 particles) based on an atomic force microscope (AFM) photograph or a transmission electron microscope (TEM) photograph.
  • AFM atomic force microscope
  • TEM transmission electron microscope
  • the method for producing two-dimensional particles of this embodiment includes: (a) the following formula: M m AX n (wherein M is at least one Group 3, 4, 5, 6, 7 metal; X is a carbon atom, a nitrogen atom, or a combination thereof; A is at least one Group 12, 13, 14, 15, 16 element; n is 1 or more and 4 or less, m is greater than n and less than or equal to 5) preparing a precursor represented by (b) using an etchant to etch away at least a portion of the A atoms from the precursor to obtain an etched product; (c) using a metal-containing compound to intercalate the etched product in a dispersion medium to obtain an intercalated product; (d) subjecting the intercalated product to a delamination treatment to obtain two-dimensional particles; The etchant contains HF and HI, The metal-containing compound comprises a Li salt, The method for producing two-dimensional particles, wherein the dispersion medium has a pH of 0.6 or more and 1.8 or less
  • a predetermined precursor that can be used in this embodiment is the MAX phase, which is a precursor of MXene, The formula below: M m AX n (wherein M is at least one Group 3, 4, 5, 6, 7 metal; X is a carbon atom, a nitrogen atom, or a combination thereof; A is at least one Group 12, 13, 14, 15, 16 element; n is 1 or more and 4 or less, m is greater than n and less than or equal to 5) is represented by
  • A is at least one Group 12, 13, 14, 15, 16 element, usually a Group A element, typically Groups IIIA and IVA, more particularly Al, Ga, In, It may contain at least one selected from the group consisting of Tl, Si, Ge, Sn, Pb, P, As, S and Cd, preferably Al.
  • a MAX phase is a crystal in which a layer composed of A atoms is located between two layers denoted by M m X n (each X may have a crystal lattice located in an octahedral array of M). have a structure.
  • the MAX phase can be produced by a known method. For example, TiC powder, Ti powder and Al powder are mixed in a ball mill, and the resulting mixed powder is fired in an Ar atmosphere to obtain a fired body (block-shaped MAX phase). After that, the obtained sintered body can be pulverized with an end mill to obtain a powdery MAX phase for the next step.
  • step (b) an etching treatment is performed to remove at least part of the A atoms from M m AX n of the precursor by etching using an etchant.
  • a processed product is obtained in which at least a portion of the layer composed of A atoms is removed while the layer represented by M m X n in the precursor is maintained.
  • the etchant contains HF and HI. As a result, it is considered that F atoms and I atoms are present on the layer represented by M m X n .
  • the form of existence of such F atom or I atom is not particularly limited. good too.
  • etching can be performed without using halogens (Cl, Br), which can be subject to regulation, and the resulting two-dimensional particles can be subject to such regulation. It becomes easy to reduce the halogen content.
  • a specific example of the etchant is a mixture of an HF aqueous solution and an HI aqueous solution.
  • the etchant may further contain HCl and LiF.
  • the concentration of HF can be, for example, 1 mol/L or more and 15 mol/L or less, further 1.5 mol/L or more and 10 mol/L or less, and particularly 2 mol/L or more and 5 mol/L or less.
  • the concentration of HI can be, for example, 1 mol/L or more and 20 mol/L or less, further 2 mol/L or more and 15 mol/L or less, and particularly 5 mol/L or more and 10 mol/L or less.
  • the total concentration of HF and HI may be, for example, 3 mol/L or more and 20 mol/L or less, further 5 mol/L or more and 15 mol/L or less, and particularly 7 mol/L or more and 10 mol/L or less.
  • the total ratio of HF and HI may be, for example, 80 mol% or more and 100 mol% or less, further 90 mol% or more and 100 mol% or less, particularly 95 mol% or more and 100 mol% or less, of the total amount of acid contained.
  • the total concentration of Cl atoms and Br atoms is, for example, 1 mmol/L or less, preferably 0.1 mmol/L or less, and particularly preferably 0.001 mmol/L or less.
  • the content of Cl atoms and Br atoms contained in the two-dimensional particles can be reduced, and the obtained two-dimensional particles can be used for so-called halogen-free applications (for example, halogen-free particles conforming to IEC Standard 61249-2-21). applications), specifically for parts used in printed circuit boards.
  • a metal-containing compound containing metal ions is used to intercalate the etched product in a dispersion medium to obtain an intercalated product. This yields an intercalated product in which the metal ions contained in the metal-containing compound are intercalated between two adjacent M m X n layers.
  • the metal ions include at least Li ions.
  • the two-dimensional particles can contain Li atoms.
  • the metal ions may further contain alkali metal ions such as Na ions and K ions, copper ions, silver ions, and gold ions as other metal ions.
  • the metal-containing compound containing the metal ion includes a salt of Li ion (also referred to as “Li salt”).
  • Li salts include sulfide salts including fluorides, iodides, phosphates, sulfates, nitrates, acetates and carboxylates of Li.
  • the metal-containing compound preferably contains an ionic compound of Li ions, more preferably contains one or more of fluoride, iodide, phosphate, and nitrate of Li ions, and contains iodide of Li ions. It is especially preferred to include By using Li ions as metal ions, the resulting two-dimensional particles can contain Li atoms.
  • the content of the Li salt in the metal-containing compound is preferably 80% by mass or more and 100% by mass or less, more preferably 90% by mass or more and 100% by mass or less, and still more preferably 95% by mass or more and 100% by mass or less.
  • the metal-containing compound may further contain salts of other metal ions, and such salts of other metal ions include fluorides, iodides, phosphates, and sulfates of other metal ions. Sulfide salts, nitrates, acetates and carboxylates are included.
  • the total content of Cl ions and Br ions is, for example, 0.1% by mass or less, preferably 0.01% by mass or less, and particularly preferably 0.0001% by mass or less.
  • the content of Cl atoms and Br atoms contained in the two-dimensional particles can be reduced, and the obtained two-dimensional particles are suitable for the halogen-free applications.
  • the pH of the dispersion containing the etching product, the metal-containing compound and the dispersion medium is 0.6 or more and 1.8 or less, for example 0.7 or more and 1.7 or less, particularly 0.8 or more and 1.5 or less. Possible.
  • the pH of the dispersion medium can be measured, for example, by measuring the pH of the supernatant after the intercalation treatment.
  • the pH of the dispersion medium can be adjusted using acids and bases, such acids including HI and such bases including LiOH.
  • the content of the etching product in the total of the etching product, the metal-containing compound, and the dispersion medium is, for example, 5 g/L or more and 50 g/L or less, further 10 g/L or more and 30 g/L or less, particularly 15 g/L or more and 25 g. /L or less.
  • the content of the metal-containing compound is within the above range, the dispersibility in the dispersion medium is good.
  • the content of the metal-containing compound in the total of the etching product, the metal-containing compound, and the dispersion medium is, for example, 0.001% by mass or more and 10% by mass or less, further 0.01% by mass or more and 1% by mass or less, particularly 0 .1 mass % or more and 1 mass % or less.
  • the content of the metal-containing compound is within the above range, the dispersibility in the dispersion medium is good.
  • the specific method of the intercalation treatment is not particularly limited, and for example, the dispersion medium, the etching treatment product and the metal-containing compound may be mixed and stirred or allowed to stand still.
  • stirring at room temperature is mentioned.
  • the stirring method include a method using a stirrer such as a stirrer, a method using a stirring blade, a method using a mixer, and a method using a centrifugal device. can be set according to the scale of production, and can be set, for example, between 12 and 24 hours.
  • the mixing order of the dispersion medium, the etching treatment product and the metal-containing compound is not particularly limited, but in one aspect, the metal treatment product may be mixed after the dispersion medium and the etching treatment product are mixed.
  • the etchant after etching treatment may be used as the dispersion medium.
  • the etched object in this step is read as the washed object.
  • step (d) the intercalated product obtained by the intercalation treatment is subjected to delamination treatment to obtain two-dimensional particles.
  • the delamination treatment includes exfoliating at least a portion between two adjacent M m X n layers by applying shear stress to the intercalation treatment.
  • the MXene particles can be made into a single layer or a small layer, and two-dimensional particles can be obtained.
  • the conditions for the delamination treatment are not particularly limited, and can be performed by a known method.
  • a method of applying shear stress to the intercalated product there is a method of dispersing the intercalated product in a dispersion medium and stirring the mixture.
  • Stirring methods include sonication, handshake, and stirring using an automatic shaker.
  • the degree of stirring such as stirring speed and stirring time may be adjusted according to the amount, concentration, etc. of the material to be treated. For example, after centrifuging the slurry after the intercalation and discarding the supernatant liquid, pure water is added to the remaining precipitate, and the layers are separated by, for example, handshaking or stirring with an automatic shaker. mentioned.
  • the removal of unexfoliated matter includes a step of centrifuging, discarding the supernatant, and washing the remaining precipitate with water. For example, (i) pure water is added to the remaining precipitate after discarding the supernatant, and the mixture is stirred, (ii) centrifuged, and (iii) the supernatant is recovered.
  • the operations (i) to (iii) are repeated once or more, preferably twice or more, and 10 times or less to obtain a supernatant liquid containing single-layer/small-layer MXene particles as a delamination-treated material. be done.
  • the supernatant may be centrifuged, the supernatant after centrifugation may be discarded, and clay containing single-layer/small-layer MXene particles may be obtained as a delamination product.
  • the monolayer ratio by delamination treatment can be understood as the yield of single-layer/low-layer MXene particles (especially single-layer MXene particles), preferably 85% by mass or more and 100% by mass or less, preferably 87% by mass. It is more than 100 mass % or less. In one aspect, the monolayer ratio by delamination treatment is allowed to be 99% by mass or less.
  • the monolayer ratio by delamination treatment is the total mass of the delamination treatment product and the etching treatment product that is not delaminated (or the cleaning treatment product of the etching treatment). It can be calculated as a value obtained by dividing
  • the single-layer/low-layer MXene particles (especially single-layer MXene particles) obtained by the delamination process are contained in the supernatant collected after repeating the above operations (i) to (iii) four times. can be understood as an MXene particle that is Also, in one aspect, it can be understood that the undelaminated etched product (or the washed etched product) is obtained as a precipitate after the delamination process.
  • the intercalation treatment in this process shall be read as the cleaning treatment.
  • a cleaning treatment shown in the following step (e) may be performed at any stage.
  • the treated material obtained by the treatment in the previous step is washed with water.
  • the acid and the like used in the treatment in the previous step can be sufficiently removed.
  • the amount of water to be mixed with the material to be treated and the washing method are not particularly limited.
  • water may be added, followed by stirring, centrifugation, and the like.
  • Stirring methods include handshake, automatic shaker, share mixer, pot mill, and the like.
  • the degree of stirring such as stirring speed and stirring time may be adjusted according to the amount, concentration, etc. of the acid-treated material to be treated.
  • the washing with water may be performed once or more.
  • the washing with water includes step (i) adding water (to the treated product or the remaining precipitate obtained in (iii) below) and stirring, and step (ii) centrifuging the stirred product.
  • Step (iii) Discard unnecessary phase after centrifugation, and may be performed by sequentially performing steps (i) to (iii) 2 times or more, for example, 15 times or less. be done.
  • the supernatant may be discarded as the unnecessary phase
  • the precipitate is discarded as the unnecessary phase.
  • the sediment may contain two-dimensional particles with a large number of layers
  • the supernatant may contain two-dimensional particles with a small number of layers (for example, two-dimensional particles with a single layer or few layers).
  • step (e) The washing treatment of step (e) is performed, for example, at one or more stages between steps (b) and (c), between steps (c) and (d), and after step (d). It is often preferred to carry out between step (b) and step (c).
  • the object to be processed in this step is read as an etching object, and when carried out between steps (c) and (d), the object to be processed in this step is In the case where intercalation treatment is performed after the step (d), the treatment in this step is read as delamination treatment.
  • the material containing the two-dimensional particles may further contain a resin.
  • resins include acrylic resins, polyester resins, polyamide resins, polyolefin resins, polycarbonate resins, polyurethane resins, polystyrene resins, polyether resins, and polylactic acid.
  • the material containing the two-dimensional particles may further contain a dispersion medium.
  • a dispersion medium include water; organic media such as N-methylpyrrolidone, N-methylformamide, N,N-dimethylformamide, methanol, ethanol, dimethylsulfoxide, ethylene glycol and acetic acid.
  • the material containing the two-dimensional particles may further contain additives such as viscosity modifiers.
  • the material containing two-dimensional particles includes, for example, a material containing only two-dimensional particles; a material containing two-dimensional particles and a resin; a material containing two-dimensional particles and a dispersion medium; Material containing; may be a material containing two-dimensional particles, a resin, a dispersion medium, and an additive.
  • the material containing the two-dimensional particles and the resin the material containing the two-dimensional particles, the resin, and the dispersion medium, and the material containing the two-dimensional particles, the resin, the dispersion medium, and the additive, the two-dimensional particles and the resin form a composite. may be formed.
  • the content of the two-dimensional particles in the material containing the two-dimensional particles may be, for example, 1% by mass or more and 100% by mass or less, further 50% by mass or more and 100% by mass or less, and particularly 70% by mass or more and 100% by mass or less.
  • the above material is suitable as a conductive material.
  • a material containing such two-dimensional particles may be in the form of a film or paste.
  • Embodiment 4 Film
  • Applications of the two-dimensional particles of the present embodiment include films containing two-dimensional particles. Such films have high moisture resistance and high smoothness.
  • the film of this embodiment will be described with reference to FIG.
  • a plurality of two-dimensional particles 10 are arranged in a two-dimensional plane direction and stacked in a direction perpendicular to the two-dimensional plane direction.
  • FIG. 2 exemplifies the film 30 obtained by stacking only the two-dimensional particles 10, the present invention is not limited to this.
  • Such a film may contain one or more selected from the resins and additives described above, if necessary.
  • Such resins can function as binders in films.
  • the conductivity of the film is preferably 2,000 S/cm or more, more preferably 5,000 S/m or more, still more preferably 10,000 S/cm or more, for example 100,000 S/cm or less, Furthermore, it may be 50,000 S/cm or less.
  • the electrical conductivity of the film of the present embodiment is obtained by substituting the thickness of the film and the surface resistivity of the film measured by the four-probe method into the following equation.
  • Conductivity [S / cm] 1 / (film thickness [cm] ⁇ film surface resistivity [ ⁇ / sq])
  • the content of two-dimensional particles in the film (dry) is preferably 70% by volume or more and 100% by volume or less, more preferably 90% by volume or more and 100% by volume or less, and even more preferably 95% by volume or more and 100% by volume or less. and most preferably 100% by volume.
  • the film is formed, for example, by suction filtering a mixed liquid containing two-dimensional particles, a dispersion medium, and the resin used as necessary, or containing two-dimensional particles, a dispersion medium, and the resin used as necessary. It can be produced by applying the mixed liquid and drying the dispersion medium once or twice or more.
  • the dispersion medium the same medium as the dispersion medium can be used, such as water; N-methylpyrrolidone, N-methylformamide, N,N-dimethylformamide, methanol, ethanol, dimethylsulfoxide, ethylene glycol, Examples include organic media such as acetic acid.
  • a supernatant liquid containing two-dimensional particles obtained by the delamination treatment may be used as the mixed liquid.
  • Examples of the method of applying the mixed liquid include a method of applying by spraying.
  • the method of spraying may be, for example, an airless spray method or an air spray method, and specific examples include a method of spraying using a nozzle such as a one-fluid nozzle, a two-fluid nozzle, and an airbrush.
  • the above film is suitable as a conductive film.
  • the paste may further contain one or more selected from the resin, the dispersion medium, and the additive, if necessary.
  • the content of the two-dimensional particles in the paste is preferably 30% by mass or more and 100% by mass or less, more preferably 50% by mass or more and 100% by mass or less, and even more preferably 70% by mass or more and 100% by mass or less.
  • the paste can be produced by mixing the two-dimensional particles with the resin, the dispersion medium, and the additive used as necessary.
  • the above paste is suitable as a conductive paste.
  • Electrode The electrode according to this embodiment includes the above film. Such an electrode may be formed only from the above-mentioned film, or may contain the above-mentioned film and, for example, one or more selected from a substrate and a protective layer.
  • Electrodes include those in a solid state to those in a flexible soft state.
  • the film may be exposed to the open air so as to be in direct contact with the object to be measured, or may be covered with a base material, a protective layer, or the like.
  • the film and the base material may be in direct contact.
  • the material of the substrate is not particularly limited, and may be, for example, an inorganic material such as ceramic or glass, or an organic material. Examples of such organic materials include flexible organic materials, and specific examples include thermoplastic polyurethane elastomers (TPU), PET films, polyimide films, and the like.
  • the material of the base material may be a fibrous material such as paper or cloth (for example, a sheet-like fibrous material).
  • Electrodes of the present embodiments may be utilized for any suitable application. Examples include counter electrodes and reference electrodes for electrochemical measurements, electrodes for electrochemical capacitors, electrodes for batteries, bio-electrodes, electrodes for sensors, and electrodes for antennas. It can also be used in applications requiring high moisture resistance (eg, reducing initial conductivity loss and preventing oxidation) such as electromagnetic shielding (EMI shielding). Details of these applications are described below.
  • EMI shielding electromagnetic shielding
  • the electrodes are not particularly limited, but may be, for example, capacitor electrodes, battery electrodes, biosignal sensing electrodes, sensor electrodes, antenna electrodes, and the like.
  • capacitor electrodes battery electrodes
  • biosignal sensing electrodes sensor electrodes
  • antenna electrodes and the like.
  • the capacitor can be an electrochemical capacitor.
  • An electrochemical capacitor is a capacitor that utilizes the capacity that is generated due to the physicochemical reaction between an electrode (electrode active material) and ions in an electrolyte (electrolyte ion). device).
  • the battery can be a chemical cell that can be repeatedly charged and discharged.
  • the battery can be, for example, but not limited to, a lithium-ion battery, a magnesium-ion battery, a lithium-sulfur battery, a sodium-ion battery, and the like.
  • a biosignal sensing electrode is an electrode for acquiring biosignals.
  • the biosignal sensing electrodes can be, but are not limited to, electrodes for measuring EEG (electroencephalogram), ECG (electrocardiogram), EMG (electromyography), EIT (electrical impedance tomography), for example.
  • the sensor electrode is an electrode for detecting the target substance, state, abnormality, etc.
  • the sensor can be, for example, a gas sensor, a biosensor (a chemical sensor that utilizes a biogenic molecular recognition mechanism), or the like, but is not limited to these.
  • the antenna electrode is an electrode for radiating electromagnetic waves into space and/or receiving electromagnetic waves in space.
  • the antenna formed by the antenna electrode is an antenna for mobile communication such as a mobile phone (so-called 3G, 4G, 5G antenna), an RFID antenna, or an NFC (Near Field Communication) antenna. Not limited.
  • the electrode of this embodiment is preferably used as an antenna electrode.
  • An electrode containing the film has high moisture resistance and high smoothness as a film. Electrodes having such characteristics can be advantageously used to extend the communication distance.
  • the two-dimensional particles in one embodiment of the present disclosure have been described in detail above, various modifications are possible.
  • the two-dimensional particles of the present disclosure may be produced by a method different from the production method in the above-described embodiment, and the two-dimensional particle production method of the present disclosure is the same as the two-dimensional particles in the above-described embodiment. Note that you are not limited to just what you provide.
  • Example 1 and 2 Comparative Examples 1 and 3 [Preparation of two-dimensional particles]
  • (1) preparation of the precursor (MAX), (2) etching of the precursor, (3) cleaning, (4) intercalation, and (5) Delamination was performed in order to prepare two-dimensional particles.
  • Precursor (MAX) preparation TiC powder, Ti powder and Al powder (all manufactured by Kojundo Chemical Laboratory Co., Ltd.) were placed in a ball mill containing zirconia balls at a molar ratio of 2:1:1. mixed for 24 hours. The obtained mixed powder was fired at 1,350° C. for 2 hours in an Ar atmosphere. The obtained sintered body (block) was pulverized with an end mill to a maximum size of 40 ⁇ m or less. This gave Ti 3 AlC 2 particles as a precursor (MAX).
  • the monolayer rate by the delamination treatment is defined as the mass of the two-dimensional particles contained in the supernatant after the delamination treatment is M 1 , the mass of the precipitate obtained after delamination is M 2 , and M 1 is M It was calculated as the value divided by the sum of 1 and M2 ( M1 /( M1 + M2 )).
  • the content of I atoms in the two-dimensional particles was 0.79% by mass in Example 1, 1.04% by mass in Example 2, and 0.69% by mass in Comparative Example 1.
  • the content of I atoms in the two-dimensional particles of Examples 1 and 2 was measured for the two-dimensional particles recovered from the supernatant liquid after the delamination treatment, and the content of I atoms in the two-dimensional particles of Comparative Example 1 was The sediment after lamination treatment was measured.
  • Two-dimensional particles (single-layer MXene particles) and dried Al 2 O 3 powder were mixed at a mass ratio of 1:9 in a glove box in an Ar atmosphere (dew point less than ⁇ 60° C.) and pulverized in an agate mortar. to obtain a mixed powder.
  • the mixed powder was packed in a zirconia sample tube for solid NMR with an outer diameter of 4 mm in the glove box, capped with a Kel-F cap, and used as a sample for NMR measurement.
  • the amount of the sample which is a combination of the two-dimensional particles (single-layer MXene particles) and the Al 2 O 3 powder, was 200 mg.
  • a Bruker AVANCE III 400 (magnetic field strength: 9.4 T, resonance frequency of 7 Li nucleus: 155.455 MHz) was used.
  • PH MAS 400S1 BL4 NP/H VTN manufactured by Bruker was used.
  • the resulting 7 Li NMR spectrum was regressed with a two-component Lorenz curve to determine the chemical shift value and relative area of each peak.
  • the reference substance was Li in a 1 mol/L LiCl aqueous solution.
  • the spectral fitting function attached to Bruker's NMR console software was used for Li regression calculation, chemical shift value and relative area calculation. From the chemical shift value, the peaks attributed to each of the first component and the second component are identified, and the relative area S 1 of the peak attributed to the first component and the relative area S 2 of the peak attributed to the second component are determined. , the ratio of the first component (atomic basis) was calculated as S 1 /(S 1 +S 2 ).
  • a simple low resistivity meter (Loresta AX MCP-T370, manufactured by Mitsubishi Chemical Analytic Co., Ltd.) was used to measure the resistivity, and the surface resistance of the film was measured by the four-probe method.
  • a micrometer (MDH-25MB manufactured by Mitutoyo Co., Ltd.) was used to measure the thickness.
  • Table 2 shows the results. In Comparative Example 1, since a single layer could not be formed and no film was obtained, 7 Li NMR measurement, conductivity measurement, and conductivity retention rate measurement were not performed.
  • the films containing the two-dimensional particles obtained in Examples 1 and 2 were capable of forming a single layer, maintained electrical conductivity even after the moisture resistance test, and had good moisture resistance.
  • the ratio of the first component to the total of the first component and the second component of Li atoms is less than 55 atomic %, and the film containing such two-dimensional particles is moisture resistant. The electrical conductivity decreased after the test, and the moisture resistance was not fully satisfactory.

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Abstract

A purpose of the present disclosure is to provide a two-dimensional particle which can provide a material having moisture resistance. Another purpose of the present disclosure is to provide: a method for producing the two-dimensional particle; and a material containing the two-dimensional particle. The two-dimensional particle according to the present disclosure has at least one layer and contains a Li atom and an I atom, in which the layer includes a layer main body represented by the formula: MmXn (wherein M represents at least one metal selected from metals belonging to Group 3, Group 4, Group 5, Group 6 and Group 7; X represents a carbon atom, a nitrogen atom or a combination thereof; n represents 1 to 4 inclusive; and m is larger than n and is 5 or less) and a modified or terminal end T present on the surface of the layer main body (wherein T represents at least one residue selected from the group consisting of a hydroxyl group, a fluorine atom, a chlorine atom, an oxygen atom and a hydrogen atom), the Li atom comprises a first component and a second component having a larger chemical shift than that of the first component in which the chemical shift is measured by 7Li NMR, and the ratio of the amount of the first component to the total amount of the first component and the second component is 55 at.% or more.

Description

２次元粒子、２次元粒子の製造方法および材料Two-dimensional particles, methods and materials for producing two-dimensional particles
　本開示は、２次元粒子、２次元粒子の製造方法および材料に関する。 The present disclosure relates to two-dimensional particles, methods for producing two-dimensional particles, and materials.
　近年、新規材料としてＭＸｅｎｅが注目されている。ＭＸｅｎｅは、いわゆる２次元材料の１種であり、後述するように、１つまたは複数の層の形態を有する層状材料である。一般的に、ＭＸｅｎｅは、かかる層状材料の粒子（粉末、フレーク、ナノシート等を含みうる）の形態を有する。 In recent years, MXene has attracted attention as a new material. MXene is a type of so-called two-dimensional material, which is a layered material having the form of one or more layers, as described below. MXenes generally have the form of particles (which can include powders, flakes, nanosheets, etc.) of such layered materials.
　現在、ＭＸｅｎｅの種々の用途への応用に向けた研究に加えて、ＭＸｅｎｅに関する様々な基礎的検討も行われている。ＭＸｅｎｅは、代表的には、前駆体であるＭＡＸ相からＡ原子を除去するエッチングと、金属カチオンのインターカレーションを経て製造されうる。非特許文献１には、エッチング液としてＨＦとＦより大きいアニオンを有する無機酸との混合物を用い、かかるアニオンが水のインターカレーションおよび脱インターカレーションを容易にし、クレイ様のＭＸｅｎｅの膨潤をもたらすことが記載されている。 Currently, in addition to research aimed at applying MXene to various uses, various basic studies on MXene are also being conducted. MXene can typically be produced via etching to remove A atoms from the precursor MAX phase and intercalation of metal cations. Non-Patent Document 1 uses a mixture of HF and an inorganic acid with anions larger than F as an etchant, and such anions facilitate intercalation and deintercalation of water, resulting in clay-like swelling of MXene. It is stated to bring
　非特許文献１には、インターカレーション時の条件に関して、１ｍｏｌ／Ｌの濃度の金属塩水溶液を用いて洗浄したことが記載されているに過ぎず、それ以上の検討は、何らなされていない。また、非特許文献１に記載のＭＸｅｎｅでは、耐湿性が十分に満足できるものではなかった。 Regarding the conditions during intercalation, Non-Patent Document 1 merely describes washing with a metal salt aqueous solution having a concentration of 1 mol/L, and does not provide any further investigation. In addition, the MXene described in Non-Patent Document 1 was not sufficiently satisfactory in moisture resistance.
　本開示は、耐湿性を有する材料を実現可能な２次元粒子の提供を目的とする。また、本開示は、かかる２次元粒子の製造方法、および、かかる２次元粒子を含む材料の提供を目的とする。 An object of the present disclosure is to provide two-dimensional particles capable of realizing a material having moisture resistance. The present disclosure also aims to provide a method for producing such two-dimensional particles and a material containing such two-dimensional particles.
［１］１つまたは複数の層を有する２次元粒子であって、
　Ｌｉ原子およびＩ原子を含み、
　前記層が、以下の式：
　　ＭｍＸｎ
　（式中、Ｍは、少なくとも１種の第３、４、５、６、７族金属であり、
　　Ｘは、炭素原子、窒素原子またはそれらの組み合わせであり、
　　ｎは、１以上４以下であり、
　　ｍは、ｎより大きく、５以下である）
で表される層本体と、該層本体の表面に存在する修飾または終端Ｔ（Ｔは、水酸基、フッ素原子、塩素原子、酸素原子および水素原子からなる群より選択される少なくとも１種である）とを含み、
　Ｌｉ原子は、第１成分と、前記第１成分よりも、７Ｌｉ　ＮＭＲにより測定される化学シフトが大きい第２成分とを含み、
　前記第１成分と前記第２成分の合計における、前記第１成分の割合は、５５原子％以上である、２次元粒子。
［２］前記Ｉ原子の含有率が、０．２質量％以上１．５質量である、［１］に記載の２次元粒子。
［３］前記Ｌｉ原子の含有率が、０．１質量％以上２０質量％以下である、［１］または［２］に記載の２次元粒子。
［４］（ａ）以下の式：
　　ＭｍＡＸｎ
　（式中、Ｍは、少なくとも１種の第３、４、５、６、７族金属であり、
　　Ｘは、炭素原子、窒素原子またはそれらの組み合わせであり、
　　Ａは、少なくとも１種の第１２、１３、１４、１５、１６族元素であり、
　　ｎは、１以上４以下であり、
　　ｍは、ｎより大きく、５以下である）
で表される前駆体を準備すること、
　（ｂ）エッチング液を用いて、前記前駆体からＡ原子の少なくとも一部をエッチングにより除去して、エッチング処理物を得ること、
　（ｃ）金属イオンを含む金属含有化合物を用いて、分散媒体中で、前記エッチング処理物に対してインターカレーション処理を行って、インターカレーション処理物を得ること、および、
　（ｄ）前記インターカレーション処理物に対してデラミネーション処理を行って、２次元粒子を得ること、を含み、
　前記エッチング液は、ＨＦおよびＨＩを含み、
　前記金属含有化合物は、Ｌｉ塩を含み、
　前記分散媒体のｐＨは、０．６以上１．８以下である、２次元粒子の製造方法。
［５］前記２次元粒子は、Ｌｉ原子を含み、
　前記Ｌｉ原子は、第１成分と、前記第１成分よりも、７Ｌｉ　ＮＭＲにより測定される化学シフトが大きい第２成分とを含み、
　前記第１成分と前記第２成分の合計における、前記第１成分の割合は、５５原子％以上である、［４］に記載の２次元粒子の製造方法。
［６］［１］～［３］のいずれか１項に記載の２次元粒子を含む材料であって、
　フィルムまたはペーストの形態である、材料。
［７］さらに樹脂を含む、［６］に記載の材料。 [1] A two-dimensional particle having one or more layers,
containing Li atoms and I atoms,
The layer has the following formula:
M m X n
(wherein M is at least one Group 3, 4, 5, 6, 7 metal;
X is a carbon atom, a nitrogen atom, or a combination thereof;
n is 1 or more and 4 or less,
m is greater than n and less than or equal to 5)
and a modification or termination T (T is at least one selected from the group consisting of a hydroxyl group, a fluorine atom, a chlorine atom, an oxygen atom and a hydrogen atom) present on the surface of the layer body represented by and
Li atoms include a first component and a second component having a larger chemical shift as measured by 7 Li NMR than the first component,
Two-dimensional particles, wherein the proportion of the first component in the total of the first component and the second component is 55 atomic % or more.
[2] The two-dimensional particle according to [1], wherein the I atom content is 0.2% by mass or more and 1.5% by mass.
[3] The two-dimensional particle according to [1] or [2], wherein the Li atom content is 0.1% by mass or more and 20% by mass or less.
[4] (a) the following formula:
M m AX n
(wherein M is at least one Group 3, 4, 5, 6, 7 metal;
X is a carbon atom, a nitrogen atom, or a combination thereof;
A is at least one Group 12, 13, 14, 15, 16 element;
n is 1 or more and 4 or less,
m is greater than n and less than or equal to 5)
preparing a precursor represented by
(b) using an etchant to etch away at least a portion of the A atoms from the precursor to obtain an etched product;
(c) using a metal-containing compound containing metal ions to intercalate the etched product in a dispersion medium to obtain an intercalated product;
(d) subjecting the intercalated product to a delamination treatment to obtain two-dimensional particles;
The etchant contains HF and HI,
The metal-containing compound comprises a Li salt,
The method for producing two-dimensional particles, wherein the dispersion medium has a pH of 0.6 or more and 1.8 or less.
[5] The two-dimensional particles contain Li atoms,
The Li atoms include a first component and a second component having a larger chemical shift as measured by 7 Li NMR than the first component,
The method for producing two-dimensional particles according to [4], wherein the ratio of the first component to the total of the first component and the second component is 55 atomic % or more.
[6] A material containing the two-dimensional particles according to any one of [1] to [3],
A material that is in the form of a film or paste.
[7] The material according to [6], which further contains a resin.
　本開示によれば、耐湿性を有する材料を実現可能な２次元粒子を提供しうる。また、本開示はかかる２次元粒子の製造方法、および、かかる２次元粒子を含む材料を提供しうる。 According to the present disclosure, it is possible to provide two-dimensional particles capable of realizing a material having moisture resistance. The present disclosure may also provide methods of making such two-dimensional particles and materials comprising such two-dimensional particles.
本開示の１つの実施形態における層状材料のＭＸｅｎｅ粒子を示す概略模式断面図であって、（ａ）は単層ＭＸｅｎｅ粒子を示し、（ｂ）は多層（例示的に二層）ＭＸｅｎｅ粒子を示す。1 is a schematic cross-sectional view showing MXene particles of a layered material in one embodiment of the present disclosure, where (a) shows a monolayer MXene particle and (b) shows a multi-layer (illustratively bi-layer) MXene particle; . 本開示の１つの実施形態における材料を示す概略模式断面図である。1 is a schematic cross-sectional view showing materials in one embodiment of the present disclosure; FIG.
　（実施形態１：２次元粒子）
　以下、本開示の１つの実施形態における２次元粒子について詳述するが、本開示はかかる実施形態に限定されない。 (Embodiment 1: Two-dimensional particles)
Two-dimensional particles in one embodiment of the present disclosure will be described in detail below, but the present disclosure is not limited to such an embodiment.
　本実施形態における２次元粒子は、１つまたは複数の層を有する層状材料の２次元粒子であって、Ｌｉ原子およびＩ原子を含む。 A two-dimensional particle in this embodiment is a two-dimensional particle of a layered material having one or more layers and contains Li atoms and I atoms.
　上記層は、以下の式：
　　ＭｍＸｎ
　（式中、Ｍは、少なくとも１種の第３、４、５、６、７族金属であり、
　　Ｘは、炭素原子、窒素原子またはそれらの組み合わせであり、
　　ｎは、１以上４以下であり、
　　ｍは、ｎより大きく、５以下である）
で表される層本体（該層本体は、各ＸがＭの八面体アレイ内に位置する結晶格子を有しうる）と、該層本体の表面（より詳細には、該層本体の互いに対向する２つの表面の少なくとも一方）に存在する修飾または終端Ｔ（Ｔは、水酸基、フッ素原子、塩素原子、酸素原子および水素原子からなる群より選択される少なくとも１種である）とを含み、
　Ｌｉ原子は、第１成分と、７Ｌｉ　ＮＭＲ（核磁気共鳴）により測定される化学シフトが上記第１成分よりも大きい第２成分とを含み、
　上記第１成分と上記第２成分の合計における、上記第１成分の割合は、５５原子％以上である。 The above layer has the following formula:
M m X n
(wherein M is at least one Group 3, 4, 5, 6, 7 metal;
X is a carbon atom, a nitrogen atom, or a combination thereof;
n is 1 or more and 4 or less,
m is greater than n and less than or equal to 5)
(the layer body may have a crystal lattice in which each X is located in an octahedral array of M) and a surface of the layer body (more particularly, the surfaces of the layer bodies facing each other a modification or termination T (T is at least one selected from the group consisting of hydroxyl groups, fluorine atoms, chlorine atoms, oxygen atoms and hydrogen atoms) present on at least one of the two surfaces that
Li atoms include a first component and a second component having a larger chemical shift than the first component as measured by 7 Li NMR (nuclear magnetic resonance),
The ratio of the first component to the total of the first component and the second component is 55 atomic % or more.
　これにより、本開示の２次元粒子を用いて得られる材料の耐湿性が良好になる。特定の理論に限定されないが、Ｌｉ原子の第１成分は、運動性が低い成分であり、第２成分は、運動性が低い成分であると考えられる。第１成分のＬｉ原子は運動性が低いため、２次元粒子中で拡散しにくく、２次元粒子の外部から水を呼び込みにくいと考えられる。そして、Ｉ原子は、他のハロゲン原子（Ｆ原子、Ｃｌ原子、Ｂｒ原子）に比べて、イオン化エネルギーが小さく、電子親和力が大きいため、酸化されやすい性質があると考えられる。そのため、Ｉ原子が含まれると、Ｉ原子が優先的に酸化されて、２次元粒子の酸化が抑制されると考えられる。２次元粒子中で、Ｌｉ原子に含まれる第１成分が第２成分よりも多い条件下において、Ｉ原子が共存することで、２次元粒子の耐湿性が向上すると考えられる。 This improves the moisture resistance of the material obtained using the two-dimensional particles of the present disclosure. Without being limited to a particular theory, it is believed that the first component of Li atoms is the less mobile component and the second component is the less mobile component. Since the Li atoms of the first component have low mobility, it is considered that they are difficult to diffuse in the two-dimensional particles and to attract water from the outside of the two-dimensional particles. The I atom has a lower ionization energy and a higher electron affinity than other halogen atoms (F atom, Cl atom, and Br atom), and thus is considered to be easily oxidized. Therefore, it is considered that when I atoms are included, the I atoms are preferentially oxidized, and the oxidation of the two-dimensional particles is suppressed. Under the condition that the first component contained in the Li atoms in the two-dimensional particles is larger than the second component, the coexistence of the I atoms is thought to improve the moisture resistance of the two-dimensional particles.
　一態様において、耐湿性は、高湿条件下で長時間置かれた場合であっても導電率を維持しうることにより評価しうる。さらに、かかる材料を含む電極は、高耐湿性が求められる用途、例えば、アンテナ用電極、特に、ＲＦＩＤ（無線識別装置：radio frequency identifier）用の電極として用いられうる。ただし、電極の用途はこれに限定されない。 In one aspect, moisture resistance can be evaluated by maintaining conductivity even when placed under high humidity conditions for a long time. Furthermore, electrodes comprising such materials can be used in applications requiring high moisture resistance, for example electrodes for antennas, in particular electrodes for RFID (radio frequency identifier). However, the use of the electrode is not limited to this.
　本開示において、ある元素について「原子」という場合、その元素の酸化数は、０に限られず、その元素の取りうる酸化数の範囲内において、任意の数でありうる。 In the present disclosure, when an element is referred to as an "atom", the oxidation number of the element is not limited to 0, and may be any number within the range of possible oxidation numbers of the element.
　上記層状材料は、層状化合物として理解され得、「ＭｍＸｎＴｓ」とも表され、ｓは任意の数であり、従来、ｓに代えてｘまたはｚが使用されることもある。代表的には、ｎは、１、２、３または４でありうるが、これに限定されない。 The layered material may be understood as a layered compound, also denoted as "M m X n T s ", where s is any number, conventionally x or z may be used instead of s. Typically, n can be 1, 2, 3 or 4, but is not so limited.
　ＭＸｅｎｅの上記式中、Ｍは、Ｔｉ、Ｚｒ、Ｈｆ、Ｖ、Ｎｂ、Ｔａ、Ｃｒ、ＭｏおよびＭｎからなる群より選択される少なくとも１つであることが好ましく、Ｔｉ、Ｖ、ＣｒおよびＭｏからなる群より選択される少なくとも１つであることがより好ましい。 In the above formula of MXene, M is preferably at least one selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo and Mn, and from Ti, V, Cr and Mo At least one selected from the group consisting of is more preferable.
　ＭＸｅｎｅは、上記の式：ＭｍＸｎが、以下のように表現されるものが知られている。
　Ｓｃ２Ｃ、Ｔｉ２Ｃ、Ｔｉ２Ｎ、Ｚｒ２Ｃ、Ｚｒ２Ｎ、Ｈｆ２Ｃ、Ｈｆ２Ｎ、Ｖ２Ｃ、Ｖ２Ｎ、Ｎｂ２Ｃ、Ｔａ２Ｃ、Ｃｒ２Ｃ、Ｃｒ２Ｎ、Ｍｏ２Ｃ、Ｍｏ１．３Ｃ、Ｃｒ１．３Ｃ、（Ｔｉ，Ｖ）２Ｃ、（Ｔｉ，Ｎｂ）２Ｃ、Ｗ２Ｃ、Ｗ１．３Ｃ、Ｍｏ２Ｎ、Ｎｂ１．３Ｃ、Ｍｏ１．３Ｙ０．６Ｃ（上記式中、「１．３」および「０．６」は、それぞれ約１．３（＝４／３）および約０．６（＝２／３）を意味する。）、
　Ｔｉ３Ｃ２、Ｔｉ３Ｎ２、Ｔｉ３（ＣＮ）、Ｚｒ３Ｃ２、（Ｔｉ，Ｖ）３Ｃ２、（Ｔｉ２Ｎｂ）Ｃ２、（Ｔｉ２Ｔａ）Ｃ２、（Ｔｉ２Ｍｎ）Ｃ２、Ｈｆ３Ｃ２、（Ｈｆ２Ｖ）Ｃ２、（Ｈｆ２Ｍｎ）Ｃ２、（Ｖ２Ｔｉ）Ｃ２、（Ｃｒ２Ｔｉ）Ｃ２、（Ｃｒ２Ｖ）Ｃ２、（Ｃｒ２Ｎｂ）Ｃ２、（Ｃｒ２Ｔａ）Ｃ２、（Ｍｏ２Ｓｃ）Ｃ２、（Ｍｏ２Ｔｉ）Ｃ２、（Ｍｏ２Ｚｒ）Ｃ２、（Ｍｏ２Ｈｆ）Ｃ２、（Ｍｏ２Ｖ）Ｃ２、（Ｍｏ２Ｎｂ）Ｃ２、（Ｍｏ２Ｔａ）Ｃ２、（Ｗ２Ｔｉ）Ｃ２、（Ｗ２Ｚｒ）Ｃ２、（Ｗ２Ｈｆ）Ｃ２、
　Ｔｉ４Ｎ３、Ｖ４Ｃ３、Ｎｂ４Ｃ３、Ｔａ４Ｃ３、（Ｔｉ，Ｎｂ）４Ｃ３、（Ｎｂ，Ｚｒ）４Ｃ３、（Ｔｉ２Ｎｂ２）Ｃ３、（Ｔｉ２Ｔａ２）Ｃ３、（Ｖ２Ｔｉ２）Ｃ３、（Ｖ２Ｎｂ２）Ｃ３、（Ｖ２Ｔａ２）Ｃ３、（Ｎｂ２Ｔａ２）Ｃ３、（Ｃｒ２Ｔｉ２）Ｃ３、（Ｃｒ２Ｖ２）Ｃ３、（Ｃｒ２Ｎｂ２）Ｃ３、（Ｃｒ２Ｔａ２）Ｃ３、（Ｍｏ２Ｔｉ２）Ｃ３、（Ｍｏ２Ｚｒ２）Ｃ３、（Ｍｏ２Ｈｆ２）Ｃ３、（Ｍｏ２Ｖ２）Ｃ３、（Ｍｏ２Ｎｂ２）Ｃ３、（Ｍｏ２Ｔａ２）Ｃ３、（Ｗ２Ｔｉ２）Ｃ３、（Ｗ２Ｚｒ２）Ｃ３、（Ｗ２Ｈｆ２）Ｃ３、（Ｍｏ２．７Ｖ１．３）Ｃ３（上記式中、「２．７」および「１．３」は、それぞれ約２．７（＝８／３）および約１．３（＝４／３）を意味する。） MXene is known in which the above formula: M m X n is expressed as follows.
Sc2C , Ti2C , Ti2N , Zr2C , Zr2N, Hf2C , Hf2N , V2C, V2N , Nb2C , Ta2C , Cr2C , Cr2 N, Mo2C , Mo1.3C , Cr1.3C , (Ti,V) 2C , (Ti,Nb) 2C , W2C , W1.3C , Mo2N , Nb1 .3 C, Mo 1.3 Y 0.6 C (wherein “1.3” and “0.6” are about 1.3 (=4/3) and about 0.6 (=2 /3)),
Ti3C2 , Ti3N2 , Ti3 ( CN ), Zr3C2 , (Ti, V) 3C2 , ( Ti2Nb )C2 , ( Ti2Ta ) C2 , ( Ti2Mn ) C2 , Hf3C2 , ( Hf2V ) C2 , (Hf2Mn) C2 , ( V2Ti ) C2 , ( Cr2Ti ) C2 , ( Cr2V ) C2 , ( Cr2Nb ) C2 , ( Cr2Ta )C2, (Mo2Sc ) C2 , ( Mo2Ti ) C2 , ( Mo2Zr ) C2 , ( Mo2Hf ) C2 , ( Mo2 V) C2 , ( Mo2Nb ) C2 , ( Mo2Ta )C2, ( W2Ti ) C2 , ( W2Zr ) C2 , ( W2Hf ) C2 ,
Ti4N3 , V4C3 , Nb4C3, Ta4C3, (Ti,Nb)4C3 , ( Nb , Zr ) 4C3 , ( Ti2Nb2 ) C3 , ( Ti2 Ta2 ) C3 , ( V2Ti2 ) C3 , (V2Nb2) C3 , ( V2Ta2 ) C3 , ( Nb2Ta2 ) C3 , ( Cr2Ti2 ) C3 , ( Cr2V2 ) C3 , ( Cr2Nb2 )C3 , ( Cr2Ta2 ) C3 , ( Mo2Ti2 ) C3 , ( Mo2Zr2 ) C3 , ( Mo2Hf 2 ) C3 , ( Mo2V2 ) C3 , ( Mo2Nb2 ) C3 , ( Mo2Ta2 ) C3 , ( W2Ti2 ) C3 , ( W2Zr2 ) C3 , (W 2 Hf 2 )C 3 , (Mo 2.7 V 1.3 )C 3 (wherein “2.7” and “1.3” are each about 2.7 (=8/3) and about 1.3 (=4/3).)
　代表的には、上記の式において、Ｍがチタンまたはバナジウムであり、Ｘが炭素原子または窒素原子でありうる。例えば、ＭＡＸ相は、Ｔｉ３ＡｌＣ２であり、ＭＸｅｎｅは、Ｔｉ３Ｃ２Ｔｓである（換言すれば、ＭがＴｉであり、ＸがＣであり、ｎが２であり、ｍが３である）。 Typically, in the above formula, M can be titanium or vanadium and X can be a carbon or nitrogen atom. For example, MAX phase is Ti 3 AlC 2 and MXene is Ti 3 C 2 T s (in other words, M is Ti, X is C, n is 2, m is 3 is).
　なお、本開示において、ＭＸｅｎｅは、前駆体のＭＡＸ相に由来するＡ原子を比較的少量、例えば元のＡ原子に対して１０質量％以下で含んでいてもよい。Ａ原子の残留量は、好ましくは８質量％以下、より好ましくは６質量％以下でありうる。しかしながら、Ａ原子の残留量は、１０質量％を超えていたとしても、２次元粒子の用途や使用条件によっては問題がない場合もありうる。 In the present disclosure, MXene may contain A atoms derived from the MAX phase of the precursor in a relatively small amount, for example, 10% by mass or less relative to the original A atoms. The residual amount of A atoms can be preferably 8% by mass or less, more preferably 6% by mass or less. However, even if the residual amount of A atoms exceeds 10% by mass, there may be no problem depending on the application and usage conditions of the two-dimensional particles.
　本開示において、上記層をＭＸｅｎｅ層という場合があり、上記２次元粒子をＭＸｅｎｅ２次元粒子またはＭＸｅｎｅ粒子という場合がある。 In the present disclosure, the layer may be referred to as an MXene layer, and the two-dimensional particles may be referred to as MXene two-dimensional particles or MXene particles.
　本実施形態の２次元粒子は、図１（ａ）に模式的に例示する１つの層のＭＸｅｎｅの粒子（以下、単に「ＭＸｅｎｅ粒子」という）１０ａ（単層ＭＸｅｎｅ粒子）を含む集合物である。ＭＸｅｎｅ粒子１０ａは、より詳細には、ＭｍＸｎで表される層本体（ＭｍＸｎ層）１ａと、層本体１ａの表面（より詳細には、各層にて互いに対向する２つの表面の少なくとも一方）に存在する修飾または終端Ｔ３ａ、５ａとを有するＭＸｅｎｅ層７ａである。よって、ＭＸｅｎｅ層７ａは、「ＭｍＸｎＴｓ」とも表され、ｓは任意の数である。 The two-dimensional particles of the present embodiment are aggregates containing one layer of MXene particles (hereinafter simply referred to as "MXene particles") 10a (single-layer MXene particles) schematically illustrated in FIG. 1(a). . More specifically, the MXene particles 10a include a layer body (M m X n layer) 1a represented by M m X n and a surface of the layer body 1a (more specifically, two surfaces facing each other in each layer). (at least one of) is the MXene layer 7a with modifications or terminations T3a, 5a present in the . Therefore, the MXene layer 7a is also expressed as "M m X n T s ", where s is any number.
　本実施形態の２次元粒子は、１つまたは複数の層を含みうる。複数の層のＭＸｅｎｅ粒子（多層ＭＸｅｎｅ粒子）として、図１（ｂ）に模式的に示す通り、２つの層のＭＸｅｎｅ粒子１０ｂが挙げられるが、これらの例に限定されない。図１（ｂ）中の、１ｂ、３ｂ、５ｂ、７ｂは、前述の図１（ａ）の１ａ、３ａ、５ａ、７ａと同じである。多層ＭＸｅｎｅ粒子の、隣接する２つのＭＸｅｎｅ層（例えば７ａと７ｂ）は、必ずしも完全に離間していなくてもよく、部分的に接触していてもよい。上記ＭＸｅｎｅ粒子１０ａは、上記多層ＭＸｅｎｅ粒子１０ｂが個々に分離されて１つの層で存在するものであり、分離されていない多層ＭＸｅｎｅ粒子１０ｂが残存し、上記単層ＭＸｅｎｅ粒子１０ａと多層ＭＸｅｎｅ粒子１０ｂの混合物である場合がある。 The two-dimensional particles of this embodiment may contain one or more layers. Examples of multiple layers of MXene particles (multilayer MXene particles) include two layers of MXene particles 10b as schematically shown in FIG. 1(b), but are not limited to these examples. 1b, 3b, 5b and 7b in FIG. 1(b) are the same as 1a, 3a, 5a and 7a in FIG. 1(a) described above. Two adjacent MXene layers ( eg 7a and 7b) of a multi-layered MXene particle are not necessarily completely separated and may be in partial contact. The above-mentioned MXene particles 10a are those in which the above-mentioned multi-layered MXene particles 10b are individually separated and exist in one layer. may be a mixture of
　本実施形態を限定するものではないが、ＭＸｅｎｅ粒子に含まれる各層（上記のＭＸｅｎｅ層７ａ、７ｂに相当する）の厚さは、例えば０．８ｎｍ以上５ｎｍ以下、特に０．８ｎｍ以上３ｎｍ以下である（主に、各層に含まれるＭ原子層の数により異なりうる）。含まれうる多層ＭＸｅｎｅ粒子の、個々の積層体について、層間距離（または空隙寸法、図１（ｂ）中にΔｄにて示す）は、例えば０．８ｎｍ以上１０ｎｍ以下、特に０．８ｎｍ以上５ｎｍ以下、より特に約１ｎｍであり、層の総数は、２以上、２０，０００以下でありうる。 Although not limited to this embodiment, the thickness of each layer (corresponding to the MXene layers 7a and 7b described above) contained in the MXene particles is, for example, 0.8 nm or more and 5 nm or less, particularly 0.8 nm or more and 3 nm or less. Yes (mainly depending on the number of M atomic layers included in each layer). For individual stacks of multilayer MXene particles that may be included, the interlayer distance (or pore size, indicated by Δd in FIG. 1(b)) is for example 0.8 nm or more and 10 nm or less, especially 0.8 nm or more and 5 nm or less. , more particularly about 1 nm, and the total number of layers can be greater than or equal to 2 and less than or equal to 20,000.
　本実施形態の２次元粒子は、上記含みうる多層ＭＸｅｎｅ粒子が、デラミネーション処理を経て得られた、層数の少ないＭＸｅｎｅ粒子であることが好ましい。上記「層数が少ない」とは、例えばＭＸｅｎｅ層の積層数が６層以下であることをいう。また、層数の少ない多層ＭＸｅｎｅ粒子の積層方向の厚さは、１５ｎｍ以下であることが好ましく、さらに好ましくは１０ｎｍ以下である。以下、この「層数の少ない多層ＭＸｅｎｅ粒子」を「少層ＭＸｅｎｅ粒子」ということがある。また、単層ＭＸｅｎｅ粒子と少層ＭＸｅｎｅ粒子を併せて「単層・少層ＭＸｅｎｅ粒子」ということがある。 In the two-dimensional particles of the present embodiment, the multilayered MXene particles that can be contained are preferably MXene particles with a small number of layers obtained through a delamination process. The phrase “the number of layers is small” means, for example, that the number of MXene layers to be stacked is 6 or less. In addition, the thickness of the multi-layered MXene particles having a small number of layers in the stacking direction is preferably 15 nm or less, more preferably 10 nm or less. Hereinafter, this "multilayer MXene particle with a small number of layers" may be referred to as "small layer MXene particle". In addition, single-layer MXene particles and low-layer MXene particles are sometimes collectively referred to as "single-layer/low-layer MXene particles."
　本実施形態の２次元粒子は、好ましくは、単層ＭＸｅｎｅ粒子と少層ＭＸｅｎｅ粒子、すなわち単層・少層ＭＸｅｎｅ粒子を含む。本実施形態の２次元粒子は、厚さが１５ｎｍ以下である単層・少層ＭＸｅｎｅ粒子の割合は、９０体積％以上であることが好ましく、より好ましくは９５体積％以上である。 The two-dimensional particles of the present embodiment preferably include single-layer MXene particles and low-layer MXene particles, ie, single-layer/low-layer MXene particles. In the two-dimensional particles of the present embodiment, the ratio of single-layer/small-layer MXene particles having a thickness of 15 nm or less is preferably 90% by volume or more, more preferably 95% by volume or more.
　上記Ｌｉ原子は、第１成分と、７Ｌｉ　ＮＭＲにより測定される化学シフトが第１成分よりも大きい第２成分とを含み、上記第１成分と上記第２成分の合計における、上記第１成分の割合は、５５原子％以上である。これにより、耐湿性を有する材料を実現しうる。上記第１成分と上記第２成分の合計における、上記第１成分の割合は、さらに５５原子％以上７０原子％以下、とりわけ５６原子％以上６５原子％以下であってよい。 The Li atoms include a first component and a second component having a larger chemical shift than the first component as measured by 7 Li NMR, and the first component in the sum of the first component and the second component is 55 atomic % or more. Thereby, a material having moisture resistance can be realized. The ratio of the first component in the total of the first component and the second component may be 55 atomic % or more and 70 atomic % or less, and particularly 56 atomic % or more and 65 atomic % or less.
　第１成分と第２成分の合計における、第１成分の割合は、７Ｌｉ　ＮＭＲにより測定できる。例えば、７Ｌｉ　ＮＭＲスペクトルにおいて、第１成分に帰属されるピークの相対面積をＳ１とし、第２成分に帰属されるピークの相対面積をＳ２としたとき、第１成分と第２成分の合計における、第１成分の割合は、Ｓ１／（Ｓ１＋Ｓ２）として算出できる。一態様において、７Ｌｉ　ＮＭＲ測定の際の積算遅延時間は、４秒とする。 The proportion of the first component in the sum of the first component and the second component can be measured by 7 Li NMR. For example, in the 7 Li NMR spectrum, when the relative area of the peak attributed to the first component is S1 and the relative area of the peak attributed to the second component is S2 , The proportion of the first component in the total can be calculated as S 1 /(S 1 +S 2 ). In one aspect, the integration delay time for the 7 Li NMR measurement is 4 seconds.
　特定の理論に拘束されないが、第１成分は、運動性の低い成分であり、第２成分は、運動性の高い成分であると考えられる。第１成分のＬｉ原子は、運動性が低いため、２次元粒子中で拡散しにくく、２次元粒子の外部から水を呼び込みにくいと考えられる。そして、第１成分と第２成分とが特定の存在比で共存することで、単層・少層化を達成しつつ、水分の吸着を防ぐことができ、高耐湿性を発揮できると考えられる。
　第１成分と第２成分の運動性は、例えば、Ｔ２緩和時間（スピン－スピン緩和時間）の比較により確認してもよい。特定の理論に拘束されないが、Ｔ２緩和時間は、各成分の運動性と関連があると考えられており、運動性が低いほど、Ｔ２緩和時間が短くなると考えられる。 Without being bound by any particular theory, it is believed that the first component is the low motile component and the second component is the high motile component. Since the Li atoms of the first component have low mobility, it is considered that they are difficult to diffuse in the two-dimensional particles and to attract water from the outside of the two-dimensional particles. It is believed that by coexisting the first component and the second component in a specific abundance ratio, it is possible to prevent adsorption of moisture while achieving a single layer and a small number of layers, and to exhibit high moisture resistance. .
The mobility of the first component and the second component may be confirmed, for example, by comparing T2 relaxation times (spin-spin relaxation times). Without being bound by theory, it is believed that the T2 relaxation time is related to the motility of each component, with lower motility resulting in shorter T2 relaxation times.
　一態様において、７Ｌｉ　ＮＭＲにより測定される第１成分の化学シフトは、例えば１．１ｐｐｍ以下、さらに０ｐｐｍ以上１．１ｐｐｍ以下、とりわけ０ｐｐｍ以上１．０５ｐｐｍ以下でありうる。また、７Ｌｉ　ＮＭＲにより測定される第２成分の化学シフトは、例えば１．１ｐｐｍ超、さらに１．１ｐｐｍ超２．０ｐｐｍ以下、とりわけ１．１５ｐｐｍ以上１．８ｐｐｍ以下でありうる。一態様において、７Ｌｉ　ＮＭＲ測定の際の基準物質は、１ｍｏｌ／Ｌ　ＬｉＣｌ水溶液におけるＬｉとする。 In one aspect, the chemical shift of the first component as measured by 7 Li NMR can be, for example, 1.1 ppm or less, even 0 ppm or more and 1.1 ppm or less, especially 0 ppm or more and 1.05 ppm or less. Also, the chemical shift of the second component measured by 7 Li NMR can be, for example, greater than 1.1 ppm, even greater than 1.1 ppm and 2.0 ppm or less, especially 1.15 ppm or more and 1.8 ppm or less. In one aspect, the reference material for 7 Li NMR measurement is Li in a 1 mol/L LiCl aqueous solution.
　本開示において、７Ｌｉ　ＮＭＲにより測定される第１成分の化学シフトは、７Ｌｉ　ＮＭＲスペクトルにおいて、第１成分に帰属されるピークの化学シフト値を表す。同様に、７Ｌｉ　ＮＭＲにより測定される第２成分の化学シフトは、７Ｌｉ　ＮＭＲスペクトルにおいて、第２成分に帰属されるピークの化学シフト値を表す。第２成分の化学シフトは、７Ｌｉ　ＮＭＲにより測定される第１成分の化学シフトよりも大きく、第２成分に帰属されるピークは、第１成分に帰属されるピークに対して、７Ｌｉ　ＮＭＲスペクトルの低磁場側に位置する。７Ｌｉ　ＮＭＲにおいて、第１成分に帰属されるピークと第２成分に帰属されるピークとが重なり合う場合、ローレンツ曲線で回帰することによりピーク分離してよい。 In the present disclosure, the chemical shift of the first component measured by 7 Li NMR represents the chemical shift value of the peak assigned to the first component in the 7 Li NMR spectrum. Similarly, the chemical shift of the second component measured by 7 Li NMR represents the chemical shift value of the peak assigned to the second component in the 7 Li NMR spectrum. The chemical shift of the second component is larger than the chemical shift of the first component measured by 7 Li NMR, and the peak attributed to the second component is relative to the peak attributed to the first component by 7 Li NMR Located on the low-field side of the spectrum. In 7 Li NMR, when the peak attributed to the first component and the peak attributed to the second component overlap, the peaks may be separated by regression using the Lorenz curve.
　上記Ｌｉ原子は、代表的には、上記層上に存在している。すなわち、上記層に接していてもよく、上記層上に他の元素を介して存在していてもよい。 The Li atoms are typically present on the layer. That is, it may be in contact with the layer or may exist on the layer via another element.
　上記２次元粒子における、Ｌｉ原子の含有率は、例えば０．１質量％以上２０質量％以下、さらに０．１質量％以上１０質量％以下、とりわけ０．２質量％以上３質量％以下、特に０．２質量％以上０．５質量％以下であってよい。 The content of Li atoms in the two-dimensional particles is, for example, 0.1% by mass or more and 20% by mass or less, further 0.1% by mass or more and 10% by mass or less, especially 0.2% by mass or more and 3% by mass or less, especially It may be 0.2% by mass or more and 0.5% by mass or less.
　上記Ｌｉ原子の含有率は、例えば、誘導結合プラズマ発光分光分析法（ＩＣＰ－ＡＥＳ）などにより測定可能である。 The Li atom content can be measured by, for example, inductively coupled plasma atomic emission spectrometry (ICP-AES).
　上記Ｉ原子は、代表的には、上記層上に存在している。すなわち、上記層に接していてもよく、上記層上に他の元素を介して存在していてもよい。 The I atom is typically present on the layer. That is, it may be in contact with the layer or may exist on the layer via another element.
　上記２次元粒子における、Ｉ原子の含有率は、例えば０．２質量％以上１．５質量％以下、さらに０．３質量％以上１．２質量％以下、とりわけ０．４質量％以上１．１質量％以下であってよい。Ｉ原子の含有率がかかる範囲にあることで、２次元粒子の耐湿性が良好になりうる。 The content of I atoms in the two-dimensional particles is, for example, 0.2% by mass or more and 1.5% by mass or less, further 0.3% by mass or more and 1.2% by mass or less, particularly 0.4% by mass or more and 1.5% by mass or less. It may be 1% by mass or less. When the I atom content is within this range, the moisture resistance of the two-dimensional particles can be improved.
　本開示の２次元粒子では、Ｃｌ原子およびＢｒ原子の含有率が低いことが好ましい。２次元粒子におけるＣｌ原子の含有率は、質量基準で、例えば０ｐｐｍ以上９００ｐｐｍ以下、さらに０ｐｐｍ以上５００ｐｐｍ以下、とりわけ０ｐｐｍ以上１００ｐｐｍ以下でありうる。２次元粒子におけるＢｒ原子の含有率は、質量基準で、例えば０ｐｐｍ以上９００ｐｐｍ以下、さらに０ｐｐｍ以上５００ｐｐｍ以下、とりわけ０ｐｐｍ以上１００ｐｐｍ以下でありうる。また、２次元粒子におけるＣｌ原子およびＢｒ原子の合計の含有率は、質量基準で、例えば１，５００ｐｐｍ以下、さらに５００ｐｐｍ以下、とりわけ１００ｐｐｍ以下でありうる。２次元粒子におけるＣｌ原子およびＢｒ原子の含有率が上記範囲にあることで、Ｃｌ原子やＢｒ原子の含有率が低いことが求められる用途（いわゆる「ハロゲンフリー用途」）に好適に用いることができる。 The two-dimensional particles of the present disclosure preferably have a low content of Cl atoms and Br atoms. The content of Cl atoms in the two-dimensional particles can be, for example, 0 ppm or more and 900 ppm or less, further 0 ppm or more and 500 ppm or less, and particularly 0 ppm or more and 100 ppm or less, based on mass. The content of Br atoms in the two-dimensional particles can be, for example, 0 ppm or more and 900 ppm or less, further 0 ppm or more and 500 ppm or less, and particularly 0 ppm or more and 100 ppm or less, on a mass basis. In addition, the total content of Cl atoms and Br atoms in the two-dimensional particles can be, for example, 1,500 ppm or less, further 500 ppm or less, and particularly 100 ppm or less on a mass basis. Since the content of Cl atoms and Br atoms in the two-dimensional particles is within the above range, it can be suitably used for applications requiring a low content of Cl atoms and Br atoms (so-called "halogen-free applications"). .
　２次元粒子におけるＣｌ原子、Ｂｒ原子およびＩ原子の濃度は、燃焼イオンクロマトグラフ法により測定することができる。 The concentration of Cl atoms, Br atoms and I atoms in two-dimensional particles can be measured by combustion ion chromatography.
　一態様において、（２次元粒子の２次元面の長径の平均値）／（２次元粒子の厚さの平均値）の比率は、１．２以上、好ましくは１．５以上、より好ましくは２以上である。上記２次元粒子の２次元面の長径の平均値と、上記２次元粒子の厚さの平均値は、後述する方法で求めればよい。 In one aspect, the ratio of (average length of two-dimensional surface of two-dimensional particles)/(average thickness of two-dimensional particles) is 1.2 or more, preferably 1.5 or more, more preferably 2 That's it. The average major diameter of the two-dimensional surfaces of the two-dimensional particles and the average thickness of the two-dimensional particles may be obtained by the method described later.
　（２次元粒子の２次元面の長径の平均値）
　本実施形態の２次元粒子は、２次元面の長径の平均値が、１μｍ以上２０μｍ以下である。以下、２次元面の長径の平均値を「平均フレークサイズ」ということがある。 (Average length of two-dimensional surface of two-dimensional particles)
In the two-dimensional particles of the present embodiment, the average value of the long diameters of the two-dimensional surfaces is 1 μm or more and 20 μm or less. Hereinafter, the average value of the major diameters of the two-dimensional surfaces may be referred to as "average flake size".
　上記平均フレークサイズが大きいほど、２次元粒子を含む材料において、２次元粒子の配向性が良好になる。２次元粒子の配向性は、例えば、２次元粒子を含む材料の導電率により評価しうる。本実施形態の２次元粒子は、平均フレークサイズが１．０μｍ以上であり大きいため、この２次元粒子を用いて形成された膜、例えばこの２次元粒子を積層させて得られる膜は、２，０００Ｓ／ｃｍ以上の導電率を達成できる。２次元面の長径の平均値は、好ましくは１．５μｍ以上、より好ましくは２．５μｍ以上である。ＭＸｅｎｅに超音波処理を施すことでＭＸｅｎｅのデラミネーション処理を行った場合、超音波処理により大部分のＭＸｅｎｅが長径で約数百ｎｍに小径化するため、超音波処理によりデラミネーションされた単層ＭＸｅｎｅで形成される膜は２次元粒子の配向性が低く、かかる２次元粒子を含む材料の導電率は低いと考えられる。 The larger the average flake size, the better the orientation of the two-dimensional particles in the material containing the two-dimensional particles. The orientation of the two-dimensional particles can be evaluated, for example, by the electrical conductivity of the material containing the two-dimensional particles. Since the two-dimensional particles of the present embodiment have a large average flake size of 1.0 μm or more, a film formed using these two-dimensional particles, for example, a film obtained by stacking these two-dimensional particles, A conductivity of 000 S/cm or more can be achieved. The average value of the long axis of the two-dimensional surface is preferably 1.5 μm or more, more preferably 2.5 μm or more. When the delamination treatment of MXene is performed by subjecting MXene to ultrasonic treatment, most of MXene is reduced in major diameter to about several hundred nm by ultrasonic treatment. It is believed that the films formed with MXene have poor orientation of the two-dimensional particles, and the electrical conductivity of materials containing such two-dimensional particles is low.
　２次元面の長径の平均値は、分散媒中の分散性の観点から、２０μｍ以下であり、好ましくは１５μｍ以下、より好ましくは１０μｍ以下である。 From the viewpoint of dispersibility in the dispersion medium, the average value of the major axis of the two-dimensional surface is 20 µm or less, preferably 15 µm or less, and more preferably 10 µm or less.
　上記２次元面の長径は、後記の実施例に示す通り、電子顕微鏡写真において、各ＭＸｅｎｅ粒子を楕円形状に近似したときの長径をいい、上記２次元面の長径の平均値は、８０粒子以上の上記長径の個数平均をいう。電子顕微鏡として、走査型電子顕微鏡（ＳＥＭ）、透過型電子顕微鏡（ＴＥＭ）写真を用いることができる。 As shown in the examples below, the major axis of the two-dimensional surface refers to the major axis of each MXene particle approximated to an elliptical shape in an electron micrograph, and the average value of the major axis of the two-dimensional surface is 80 particles or more. The number average of the above major diameters. Scanning electron microscope (SEM) and transmission electron microscope (TEM) photographs can be used as electron microscopes.
　本実施形態の２次元粒子の長径の平均値は、該２次元粒子を含む材料を溶媒に溶解させ、上記２次元粒子を該溶媒に分散させて測定してもよい。または、上記材料のＳＥＭ画像から測定してもよい。 The average value of the major diameters of the two-dimensional particles of the present embodiment may be measured by dissolving a material containing the two-dimensional particles in a solvent and dispersing the two-dimensional particles in the solvent. Alternatively, it may be measured from an SEM image of the material.
　（２次元粒子の厚さの平均値）
　本実施形態の２次元粒子の厚さの平均値は、１ｎｍ以上１５ｎｍ以下であることが好ましい。上記厚さは、好ましくは１０ｎｍ以下であり、より好ましくは７ｎｍ以下であり、さらに好ましくは５ｎｍ以下である。一方、単層ＭＸｅｎｅ粒子の厚さを考慮すると、２次元粒子の厚さの下限は１ｎｍとなりうる。 (Average thickness of two-dimensional particles)
The average thickness of the two-dimensional particles of the present embodiment is preferably 1 nm or more and 15 nm or less. The thickness is preferably 10 nm or less, more preferably 7 nm or less, and even more preferably 5 nm or less. On the other hand, considering the thickness of monolayer MXene particles, the lower limit of the thickness of two-dimensional particles can be 1 nm.
　上記２次元粒子の厚さの平均値は、原子間力顕微鏡（ＡＦＭ）写真または透過型電子顕微鏡（ＴＥＭ）写真に基づく数平均寸法（例えば少なくとも４０個の数平均）として求められる。 The average value of the thickness of the two-dimensional particles is obtained as a number average dimension (for example, number average of at least 40 particles) based on an atomic force microscope (AFM) photograph or a transmission electron microscope (TEM) photograph.
　（実施形態２：２次元粒子の製造方法）
　以下、本開示の１つの実施形態における２次元粒子の製造方法について詳述するが、本開示はかかる実施形態に限定されるものではない。 (Embodiment 2: Method for producing two-dimensional particles)
A method for producing two-dimensional particles according to one embodiment of the present disclosure will be described in detail below, but the present disclosure is not limited to such an embodiment.
　本実施形態の２次元粒子の製造方法は、
　（ａ）以下の式：
　　ＭｍＡＸｎ
　（式中、Ｍは、少なくとも１種の第３、４、５、６、７族金属であり、
　　Ｘは、炭素原子、窒素原子またはそれらの組み合わせであり、
　　Ａは、少なくとも１種の第１２、１３、１４、１５、１６族元素であり、
　　ｎは、１以上４以下であり、
　　ｍは、ｎより大きく、５以下である）
で表される前駆体を準備すること、
　（ｂ）エッチング液を用いて、前記前駆体からＡ原子の少なくとも一部をエッチングにより除去して、エッチング処理物を得ること、
　（ｃ）金属含有化合物を用いて、分散媒体中で、前記エッチング処理物に対してインターカレーション処理を行って、インターカレーション処理物を得ること、および、
　（ｄ）前記インターカレーション処理物に対してデラミネーション処理を行って、２次元粒子を得ること、を含み、
　前記エッチング液は、ＨＦおよびＨＩを含み、
　前記金属含有化合物は、Ｌｉ塩を含み、
　前記分散媒体のｐＨは、０．６以上１．８以下である、２次元粒子の製造方法。 The method for producing two-dimensional particles of this embodiment includes:
(a) the following formula:
M m AX n
(wherein M is at least one Group 3, 4, 5, 6, 7 metal;
X is a carbon atom, a nitrogen atom, or a combination thereof;
A is at least one Group 12, 13, 14, 15, 16 element;
n is 1 or more and 4 or less,
m is greater than n and less than or equal to 5)
preparing a precursor represented by
(b) using an etchant to etch away at least a portion of the A atoms from the precursor to obtain an etched product;
(c) using a metal-containing compound to intercalate the etched product in a dispersion medium to obtain an intercalated product;
(d) subjecting the intercalated product to a delamination treatment to obtain two-dimensional particles;
The etchant contains HF and HI,
The metal-containing compound comprises a Li salt,
The method for producing two-dimensional particles, wherein the dispersion medium has a pH of 0.6 or more and 1.8 or less.
　以下、各工程について詳述する。 Each step will be described in detail below.
・工程（ａ）
　まず、所定の前駆体を準備する。本実施形態において使用可能な所定の前駆体は、ＭＸｅｎｅの前駆体であるＭＡＸ相であり、
以下の式：
　　ＭｍＡＸｎ
　（式中、Ｍは、少なくとも１種の第３、４、５、６、７族金属であり、
　　Ｘは、炭素原子、窒素原子またはそれらの組み合わせであり、
　　Ａは、少なくとも１種の第１２、１３、１４、１５、１６族元素であり、
　　ｎは、１以上４以下であり、
　　ｍは、ｎより大きく、５以下である）
で表される。 ・Step (a)
First, a predetermined precursor is prepared. A predetermined precursor that can be used in this embodiment is the MAX phase, which is a precursor of MXene,
The formula below:
M m AX n
(wherein M is at least one Group 3, 4, 5, 6, 7 metal;
X is a carbon atom, a nitrogen atom, or a combination thereof;
A is at least one Group 12, 13, 14, 15, 16 element;
n is 1 or more and 4 or less,
m is greater than n and less than or equal to 5)
is represented by
　上記Ｍ、Ｘ、ｎおよびｍは、第１実施形態で説明した通りである。Ａは、少なくとも１種の第１２、１３、１４、１５、１６族元素であり、通常はＡ族元素、代表的にはIIIA族およびIVA族であり、より詳細にはＡｌ、Ｇａ、Ｉｎ、Ｔｌ、Ｓｉ、Ｇｅ、Ｓｎ、Ｐｂ、Ｐ、Ａｓ、ＳおよびＣｄからなる群より選択される少なくとも１種を含み得、好ましくはＡｌである。 The above M, X, n and m are as described in the first embodiment. A is at least one Group 12, 13, 14, 15, 16 element, usually a Group A element, typically Groups IIIA and IVA, more particularly Al, Ga, In, It may contain at least one selected from the group consisting of Tl, Si, Ge, Sn, Pb, P, As, S and Cd, preferably Al.
　ＭＡＸ相は、ＭｍＸｎで表される２つの層（各ＸがＭの八面体アレイ内に位置する結晶格子を有しうる）の間に、Ａ原子により構成される層が位置した結晶構造を有する。ＭＡＸ相は、代表的にｍ＝ｎ＋１の場合、ｎ＋１層のＭ原子の層の各間にＸ原子の層が１層ずつ配置され（これらを合わせて「ＭｍＸｎ層」とも称する）、ｎ＋１番目のＭ原子の層の次の層としてＡ原子の層（「Ａ原子層」）が配置された繰り返し単位を有するが、これに限定されない。 A MAX phase is a crystal in which a layer composed of A atoms is located between two layers denoted by M m X n (each X may have a crystal lattice located in an octahedral array of M). have a structure. In the MAX phase, typically, when m=n+1, one layer of X atoms is arranged between each of the n+1 layers of M atoms (together, these are also referred to as “M m X n layers”), It has a repeating unit in which a layer of A atoms (“A atom layer”) is arranged as a layer next to the n+1-th layer of M atoms, but is not limited to this.
　上記ＭＡＸ相は、既知の方法で製造することができる。例えばＴｉＣ粉末、Ｔｉ粉末およびＡｌ粉末を、ボールミルで混合し、得られた混合粉末をＡｒ雰囲気下で焼成し、焼成体（ブロック状のＭＡＸ相）を得る。その後、得られた焼成体をエンドミルで粉砕して次工程用の粉末状ＭＡＸ相を得ることができる。 The MAX phase can be produced by a known method. For example, TiC powder, Ti powder and Al powder are mixed in a ball mill, and the resulting mixed powder is fired in an Ar atmosphere to obtain a fired body (block-shaped MAX phase). After that, the obtained sintered body can be pulverized with an end mill to obtain a powdery MAX phase for the next step.
・工程（ｂ）
　工程（ｂ）では、エッチング液を用いて、上記前駆体のＭｍＡＸｎからＡ原子の少なくとも一部をエッチングにより除去する、エッチング処理を行う。これにより、前駆体におけるＭｍＸｎで表される層は維持されたまま、Ａ原子により構成される層の少なくとも一部が除去された処理物が得られる。 ・Process (b)
In step (b), an etching treatment is performed to remove at least part of the A atoms from M m AX n of the precursor by etching using an etchant. As a result, a processed product is obtained in which at least a portion of the layer composed of A atoms is removed while the layer represented by M m X n in the precursor is maintained.
　上記エッチング液は、ＨＦとＨＩとを含む。これにより、ＭｍＸｎで表される層上に、Ｆ原子やＩ原子が存在した状態になると考えられる。かかるＦ原子やＩ原子の存在形態は特に限定されず、イオンとして存在していてもよく、Ｈ＋と結合して酸として存在していてもよく、カチオンと結合して塩として存在していてもよい。
　また、上記エッチング液にＨＦとＨＩとを用いるため、規制対象となりうるハロゲン（Ｃｌ、Ｂｒ）を用いることなくエッチング処理を行うことが可能であり、得られる２次元粒子において、かかる規制対象となりうるハロゲンの含有率を低くすることが容易となる。 The etchant contains HF and HI. As a result, it is considered that F atoms and I atoms are present on the layer represented by M m X n . The form of existence of such F atom or I atom is not particularly limited. good too.
In addition, since HF and HI are used in the etching solution, etching can be performed without using halogens (Cl, Br), which can be subject to regulation, and the resulting two-dimensional particles can be subject to such regulation. It becomes easy to reduce the halogen content.
　上記エッチング液の具体例としては、ＨＦの水溶液と、ＨＩの水溶液との混合液が挙げられる。上記エッチング液は、ＨＣｌ、ＬｉＦをさらに含んでいてもよい。 A specific example of the etchant is a mixture of an HF aqueous solution and an HI aqueous solution. The etchant may further contain HCl and LiF.
　上記エッチング液において、ＨＦの濃度は、例えば１ｍｏｌ／Ｌ以上１５ｍｏｌ／Ｌ以下、さらに１．５ｍｏｌ／Ｌ以上１０ｍｏｌ／Ｌ以下、とりわけ２ｍｏｌ／Ｌ以上５ｍｏｌ／Ｌ以下でありうる。 In the etching solution, the concentration of HF can be, for example, 1 mol/L or more and 15 mol/L or less, further 1.5 mol/L or more and 10 mol/L or less, and particularly 2 mol/L or more and 5 mol/L or less.
　上記エッチング液において、ＨＩの濃度は、例えば１ｍｏｌ／Ｌ以上２０ｍｏｌ／Ｌ以下、さらに２ｍｏｌ／Ｌ以上１５ｍｏｌ／Ｌ以下、とりわけ５ｍｏｌ／Ｌ以上１０ｍｏｌ／Ｌ以下でありうる。 In the etching solution, the concentration of HI can be, for example, 1 mol/L or more and 20 mol/L or less, further 2 mol/L or more and 15 mol/L or less, and particularly 5 mol/L or more and 10 mol/L or less.
　また、上記エッチング液において、ＨＦの濃度とＨＩの濃度の合計は、例えば３ｍｏｌ／Ｌ以上２０ｍｏｌ／Ｌ以下、さらに５ｍｏｌ／Ｌ以上１５ｍｏｌ／Ｌ以下、とりわけ７ｍｏｌ／Ｌ以上１０ｍｏｌ／Ｌ以下でありうる。 In the etching solution, the total concentration of HF and HI may be, for example, 3 mol/L or more and 20 mol/L or less, further 5 mol/L or more and 15 mol/L or less, and particularly 7 mol/L or more and 10 mol/L or less. .
　上記エッチング液において、ＨＦとＨＩとの合計割合は、含まれる酸の全量中、例えば８０ｍｏｌ％以上１００ｍｏｌ％以下、さらに９０ｍｏｌ％以上１００ｍｏｌ％以下、特に９５ｍｏｌ％以上１００ｍｏｌ％以下であってよい。 In the etching solution, the total ratio of HF and HI may be, for example, 80 mol% or more and 100 mol% or less, further 90 mol% or more and 100 mol% or less, particularly 95 mol% or more and 100 mol% or less, of the total amount of acid contained.
　上記エッチング液において、Ｃｌ原子およびＢｒ原子の合計濃度は、例えば１ｍｍｏｌ／Ｌ以下、さらに０．１ｍｍｏｌ／Ｌ以下、特に０．００１ｍｍｏｌ／Ｌ以下であることが好ましい。これにより、２次元粒子に含まれるＣｌ原子およびＢｒ原子の含有率を低くすることができ、得られる２次元粒子は、いわゆるハロゲンフリー用途（例えば、ＩＥＣ規格６１２４９－２－２１に準拠したハロゲンフリーの用途）、具体的にはプリント基板に用いられる部品に適したものとなる。 In the etching solution, the total concentration of Cl atoms and Br atoms is, for example, 1 mmol/L or less, preferably 0.1 mmol/L or less, and particularly preferably 0.001 mmol/L or less. As a result, the content of Cl atoms and Br atoms contained in the two-dimensional particles can be reduced, and the obtained two-dimensional particles can be used for so-called halogen-free applications (for example, halogen-free particles conforming to IEC Standard 61249-2-21). applications), specifically for parts used in printed circuit boards.
　上記エッチング液を用いたエッチングの操作およびその他の条件としては、従来実施されている条件を採用できる。 As for the etching operation and other conditions using the etching solution, conventionally used conditions can be adopted.
・工程（ｃ）
　金属イオンを含む金属含有化合物を用いて、分散媒体中で、前記エッチング処理物に対してインターカレーション処理を行って、インターカレーション処理物を得る、インターカレーション処理を行う。これにより、金属含有化合物に含まれる金属イオンが、２つの隣り合うＭｍＸｎ層の間にインターカレートされた、インターカレーション処理物が得られる。 ・Process (c)
A metal-containing compound containing metal ions is used to intercalate the etched product in a dispersion medium to obtain an intercalated product. This yields an intercalated product in which the metal ions contained in the metal-containing compound are intercalated between two adjacent M m X n layers.
　上記金属イオンは、少なくともＬｉイオンを含む。これにより、２次元粒子がＬｉ原子を含むものとすることができる。上記金属イオンは、その他の金属イオンとして、ＮａイオンおよびＫイオン等のアルカリ金属イオン、銅イオン、銀イオン、金イオンをさらに含んでいてもよい。 The metal ions include at least Li ions. Thereby, the two-dimensional particles can contain Li atoms. The metal ions may further contain alkali metal ions such as Na ions and K ions, copper ions, silver ions, and gold ions as other metal ions.
　上記金属イオンを含む金属含有化合物は、Ｌｉイオンの塩（「Ｌｉ塩」ともいう）を含む。これにより、２次元粒子がＬｉ原子を含むものとすることができる。かかるＬｉ塩としては、Ｌｉのフッ化物、ヨウ化物、リン酸塩、硫酸塩を含む硫化物塩、硝酸塩、酢酸塩、カルボン酸塩が挙げられる。
　上記金属含有化合物は、Ｌｉイオンのイオン性化合物を含むことが好ましく、Ｌｉイオンのフッ化物、ヨウ化物、リン酸塩、硝酸塩のうちの１以上を含むことがさらに好ましく、Ｌｉイオンのヨウ化物を含むことがとりわけ好ましい。金属イオンとしてＬｉイオンを用いることにより、得られる２次元粒子がＬｉ原子を含むものとなりうる。 The metal-containing compound containing the metal ion includes a salt of Li ion (also referred to as “Li salt”). Thereby, the two-dimensional particles can contain Li atoms. Such Li salts include sulfide salts including fluorides, iodides, phosphates, sulfates, nitrates, acetates and carboxylates of Li.
The metal-containing compound preferably contains an ionic compound of Li ions, more preferably contains one or more of fluoride, iodide, phosphate, and nitrate of Li ions, and contains iodide of Li ions. It is especially preferred to include By using Li ions as metal ions, the resulting two-dimensional particles can contain Li atoms.
　上記Ｌｉ塩の含有率は、金属含有化合物中、好ましくは８０質量％以上１００質量％以下、より好ましくは９０質量％以上１００質量％以下、さらに好ましくは９５質量％以上１００質量％以下である。 The content of the Li salt in the metal-containing compound is preferably 80% by mass or more and 100% by mass or less, more preferably 90% by mass or more and 100% by mass or less, and still more preferably 95% by mass or more and 100% by mass or less.
　上記金属含有化合物は、さらに、その他の金属イオンの塩を含んでいてもよく、かかるその他の金属イオンの塩としては、その他の金属イオンのフッ化物、ヨウ化物、リン酸塩、硫酸塩を含む硫化物塩、硝酸塩、酢酸塩、カルボン酸塩が挙げられる。 The metal-containing compound may further contain salts of other metal ions, and such salts of other metal ions include fluorides, iodides, phosphates, and sulfates of other metal ions. Sulfide salts, nitrates, acetates and carboxylates are included.
　上記金属含有化合物において、ＣｌイオンおよびＢｒイオンの合計の含有率は、例えば０．１質量％以下、さらに０．０１質量％以下、特に０．０００１質量％以下であることが好ましい。これにより、２次元粒子に含まれるＣｌ原子およびＢｒ原子の含有率を低くすることができ、得られる２次元粒子は、上記ハロゲンフリー用途に適したものとなる。 In the metal-containing compound, the total content of Cl ions and Br ions is, for example, 0.1% by mass or less, preferably 0.01% by mass or less, and particularly preferably 0.0001% by mass or less. As a result, the content of Cl atoms and Br atoms contained in the two-dimensional particles can be reduced, and the obtained two-dimensional particles are suitable for the halogen-free applications.
　上記エッチング処理物、金属含有化合物および分散媒体を含む分散液のｐＨは、０．６以上１．８以下であり、例えば０．７以上１．７以下、とりわけ０．８以上１．５以下でありうる。分散媒体のｐＨがかかる範囲にあることで、後述するデラミネーション処理において、単層化が容易になるとともに、Ｌｉ原子に含まれる第１成分の割合を高めることができる。上記分散液のｐＨは、例えば、インターカレーション処理後の上澄み液のｐＨを測定することにより測定できる。上記分散媒体のｐＨは、酸および塩基を用いて調整でき、かかる酸としては、ＨＩが挙げられ、かかる塩基としては、ＬｉＯＨが挙げられる。 The pH of the dispersion containing the etching product, the metal-containing compound and the dispersion medium is 0.6 or more and 1.8 or less, for example 0.7 or more and 1.7 or less, particularly 0.8 or more and 1.5 or less. Possible. When the pH of the dispersion medium is in such a range, it is possible to easily form a single layer and increase the ratio of the first component contained in the Li atoms in the delamination treatment described below. The pH of the dispersion can be measured, for example, by measuring the pH of the supernatant after the intercalation treatment. The pH of the dispersion medium can be adjusted using acids and bases, such acids including HI and such bases including LiOH.
　上記エッチング処理物と金属含有化合物と分散媒体との合計における、エッチング処理物の含有率は、例えば５ｇ／Ｌ以上５０ｇ／Ｌ以下、さらに１０ｇ／Ｌ以上３０ｇ／Ｌ以下、とりわけ１５ｇ／Ｌ以上２５ｇ／Ｌ以下でありうる。金属含有化合物の含有率が前記範囲にあると、分散媒体中における分散性が良好である。 The content of the etching product in the total of the etching product, the metal-containing compound, and the dispersion medium is, for example, 5 g/L or more and 50 g/L or less, further 10 g/L or more and 30 g/L or less, particularly 15 g/L or more and 25 g. /L or less. When the content of the metal-containing compound is within the above range, the dispersibility in the dispersion medium is good.
　上記エッチング処理物と金属含有化合物と分散媒体との合計における、金属含有化合物の含有率は、例えば０．００１質量％以上１０質量％以下、さらに０．０１質量％以上１質量％以下、とりわけ０．１質量％以上１質量％以下でありうる。金属含有化合物の含有率が前記範囲にあると、分散媒体中における分散性が良好である。 The content of the metal-containing compound in the total of the etching product, the metal-containing compound, and the dispersion medium is, for example, 0.001% by mass or more and 10% by mass or less, further 0.01% by mass or more and 1% by mass or less, particularly 0 .1 mass % or more and 1 mass % or less. When the content of the metal-containing compound is within the above range, the dispersibility in the dispersion medium is good.
　インターカレーション処理の具体的な方法は特に限定されず、例えば、分散媒体とエッチング処理物と金属含有化合物とを混合し、撹拌を行ってもよいし、静置してもよい。例えば室温で撹拌することが挙げられる。上記撹拌の方法は、例えば、スターラー等の撹拌子を用いる方法、撹拌翼を用いる方法、ミキサーを用いる方法、および遠心装置を用いる方法等が挙げられ、撹拌時間は、単層・少層ＭＸｅｎｅ粒子の製造規模に応じて設定することができ、例えば１２～２４時間の間で設定できる。分散媒体とエッチング処理物と金属含有化合物の混合順序は特に限定されないが、一態様において、分散媒体とエッチング処理物とを混合した後、金属処理物を混合してもよい。代表的には、エッチング処理を行った後のエッチング液を、分散媒体としてよい。 The specific method of the intercalation treatment is not particularly limited, and for example, the dispersion medium, the etching treatment product and the metal-containing compound may be mixed and stirred or allowed to stand still. For example, stirring at room temperature is mentioned. Examples of the stirring method include a method using a stirrer such as a stirrer, a method using a stirring blade, a method using a mixer, and a method using a centrifugal device. can be set according to the scale of production, and can be set, for example, between 12 and 24 hours. The mixing order of the dispersion medium, the etching treatment product and the metal-containing compound is not particularly limited, but in one aspect, the metal treatment product may be mixed after the dispersion medium and the etching treatment product are mixed. Typically, the etchant after etching treatment may be used as the dispersion medium.
　エッチング処理とインターカレーション処理の間に、後述する洗浄処理を実施する場合、本工程におけるエッチング処理物を洗浄処理物と読み替える。 When the cleaning treatment described later is performed between the etching treatment and the intercalation treatment, the etched object in this step is read as the washed object.
・工程（ｄ）
　工程（ｄ）では、インターカレーション処理を行って得られたインターカレーション処理物に対してデラミネーション処理を行って、２次元粒子を得る。デラミネーション処理は、インターカレーション処理物に対して、せん断応力を加えることにより、隣り合う２つのＭｍＸｎ層の間の少なくとも一部を剥離することを含む。デラミネーション処理により、ＭＸｅｎｅ粒子の単層・少層化を図り、２次元粒子を得ることができる。 ・Process (d)
In step (d), the intercalated product obtained by the intercalation treatment is subjected to delamination treatment to obtain two-dimensional particles. The delamination treatment includes exfoliating at least a portion between two adjacent M m X n layers by applying shear stress to the intercalation treatment. By the delamination treatment, the MXene particles can be made into a single layer or a small layer, and two-dimensional particles can be obtained.
　デラミネーション処理の条件は特に限定されず、既知の方法で行うことができる。例えば、インターカレーション処理物に対してせん断応力を加える方法として、分散媒体中に、インターカレーション処理物を分散させて、撹拌する方法が挙げられる。撹拌方法としては、超音波処理、ハンドシェイク、オートマチックシェーカーなどを用いた撹拌が挙げられる。撹拌速度、撹拌時間等の撹拌の程度は、処理対象となる処理物の量や濃度等に応じて調整すればよい。例えば、上記インターカレーション後のスラリーを、遠心分離して上澄み液を廃棄した後に、残りの沈殿物に純水を添加し、例えばハンドシェイクまたはオートマチックシェーカーによる撹拌を行って層分離を行うことが挙げられる。未剥離物の除去は、遠心分離して上澄みを廃棄後、残りの沈殿物を水で洗浄する工程が挙げられる。例えば、（i）上澄み廃棄後の残りの沈殿物に、純水を追加して撹拌、（ii）遠心分離し、（iii）上澄み液を回収する。この（i）～（iii）の操作を、１回以上、好ましくは２回以上、１０回以下繰り返して、デラミネーション処理物として、単層・少層ＭＸｅｎｅ粒子を含む上澄み液を得ることが挙げられる。または、この上澄み液を遠心分離して、遠心分離後の上澄み液を廃棄し、デラミネーション処理物として単層・少層ＭＸｅｎｅ粒子を含むクレイを得てもよい。 The conditions for the delamination treatment are not particularly limited, and can be performed by a known method. For example, as a method of applying shear stress to the intercalated product, there is a method of dispersing the intercalated product in a dispersion medium and stirring the mixture. Stirring methods include sonication, handshake, and stirring using an automatic shaker. The degree of stirring such as stirring speed and stirring time may be adjusted according to the amount, concentration, etc. of the material to be treated. For example, after centrifuging the slurry after the intercalation and discarding the supernatant liquid, pure water is added to the remaining precipitate, and the layers are separated by, for example, handshaking or stirring with an automatic shaker. mentioned. The removal of unexfoliated matter includes a step of centrifuging, discarding the supernatant, and washing the remaining precipitate with water. For example, (i) pure water is added to the remaining precipitate after discarding the supernatant, and the mixture is stirred, (ii) centrifuged, and (iii) the supernatant is recovered. The operations (i) to (iii) are repeated once or more, preferably twice or more, and 10 times or less to obtain a supernatant liquid containing single-layer/small-layer MXene particles as a delamination-treated material. be done. Alternatively, the supernatant may be centrifuged, the supernatant after centrifugation may be discarded, and clay containing single-layer/small-layer MXene particles may be obtained as a delamination product.
　本実施形態の製造方法では、デラミネーション処理の際、超音波処理を行わなくともよい。超音波処理を行わない場合、粒子破壊が生じ難く、粒子の層に平行な平面、すなわち２次元面の大きい単層・少層ＭＸｅｎｅ粒子を得ることが容易となる。 In the manufacturing method of this embodiment, it is not necessary to perform ultrasonic treatment during the delamination process. When ultrasonic treatment is not performed, particle destruction is less likely to occur, and it becomes easy to obtain single-layer/small-layer MXene particles with large two-dimensional planes, that is, planes parallel to the layer of particles.
　デラミネーション処理による単層化率は、単層・少層ＭＸｅｎｅ粒子（特に単層ＭＸｅｎｅ粒子）の収率として理解され得、好ましくは８５質量％以上１００質量％以下であり、好ましくは８７質量％以上１００質量％以下である。一態様において、デラミネーション処理による単層化率は、９９質量％以下であることも許容される。 The monolayer ratio by delamination treatment can be understood as the yield of single-layer/low-layer MXene particles (especially single-layer MXene particles), preferably 85% by mass or more and 100% by mass or less, preferably 87% by mass. It is more than 100 mass % or less. In one aspect, the monolayer ratio by delamination treatment is allowed to be 99% by mass or less.
　本開示において、デラミネーション処理による単層化率は、デラミネーション処理物の質量を、デラミネーション処理物およびデラミネーションされなかったエッチング処理物（またはエッチング処理物の洗浄処理物）の合計の質量で除した値として算出できる。一態様において、デラミネーション処理により得られた単層・少層ＭＸｅｎｅ粒子（特に単層ＭＸｅｎｅ粒子）は、上記（i）～（iii）の操作を、４回繰り返した後に回収した上澄み液に含まれるＭＸｅｎｅ粒子と理解されうる。また、一態様において、デラミネーションされなかったエッチング処理物（またはエッチング処理物の洗浄処理物）は、デラミネーション処理後の沈殿物として得られるものと理解されうる。 In the present disclosure, the monolayer ratio by delamination treatment is the total mass of the delamination treatment product and the etching treatment product that is not delaminated (or the cleaning treatment product of the etching treatment). It can be calculated as a value obtained by dividing In one embodiment, the single-layer/low-layer MXene particles (especially single-layer MXene particles) obtained by the delamination process are contained in the supernatant collected after repeating the above operations (i) to (iii) four times. can be understood as an MXene particle that is Also, in one aspect, it can be understood that the undelaminated etched product (or the washed etched product) is obtained as a precipitate after the delamination process.
　インターカレーション処理とデラミネーション処理の間に、後述する洗浄処理を実施する場合、本工程におけるインターカレーション処理物を洗浄処理物と読み替えるものとする。 When the cleaning treatment described below is performed between the intercalation treatment and the delamination treatment, the intercalation treatment in this process shall be read as the cleaning treatment.
　本開示における２次元粒子の製造方法では、任意の段階で、以下の工程（ｅ）に示す洗浄処理を実施してよい。
・工程（ｅ）
　前工程の処理により得られた処理物を、水洗浄する。水洗浄を行うことによって、上記前工程の処理で用いた酸等を十分に除去できる。処理物と混合させる水の量や洗浄方法は特に限定されない。例えば水を加えて撹拌、遠心分離等を行うことが挙げられる。撹拌方法として、ハンドシェイク、オートマチックシェーカー、シェアミキサー、ポットミルなどを用いた撹拌が挙げられる。撹拌速度、撹拌時間等の撹拌の程度は、処理対象となる酸処理物の量や濃度等に応じて調整すればよい。上記水での洗浄は１回以上行えばよい。好ましくは水での洗浄を複数回行うことである。例えば具体的に、上記水での洗浄は、工程（i）（処理物または下記（iii）で得られた残りの沈殿物に）水を加えて撹拌、工程（ii）撹拌物を遠心分離する、工程（iii）遠心分離後に不要な相を廃棄する、を順次行うことにより実施してよく、工程（i）～（iii）を２回以上、例えば１５回以下の範囲内で行うことが挙げられる。
　沈殿物を回収することを目的とする場合は、上澄み液を上記不要な相として廃棄してよく、上澄み液を回収することを目的とする場合は、沈殿物を上記不要な相として廃棄してよい。代表的には、沈殿物には層数が多い２次元粒子が含まれ、上澄み液には層数が少ない２次元粒子（例えば、単層・少層の２次元粒子）が含まれうる。 In the method for producing two-dimensional particles according to the present disclosure, a cleaning treatment shown in the following step (e) may be performed at any stage.
・Process (e)
The treated material obtained by the treatment in the previous step is washed with water. By washing with water, the acid and the like used in the treatment in the previous step can be sufficiently removed. The amount of water to be mixed with the material to be treated and the washing method are not particularly limited. For example, water may be added, followed by stirring, centrifugation, and the like. Stirring methods include handshake, automatic shaker, share mixer, pot mill, and the like. The degree of stirring such as stirring speed and stirring time may be adjusted according to the amount, concentration, etc. of the acid-treated material to be treated. The washing with water may be performed once or more. It is preferable to wash with water several times. Specifically, for example, the washing with water includes step (i) adding water (to the treated product or the remaining precipitate obtained in (iii) below) and stirring, and step (ii) centrifuging the stirred product. , Step (iii) Discard unnecessary phase after centrifugation, and may be performed by sequentially performing steps (i) to (iii) 2 times or more, for example, 15 times or less. be done.
When the purpose is to collect the precipitate, the supernatant may be discarded as the unnecessary phase, and when the purpose is to collect the supernatant, the precipitate is discarded as the unnecessary phase. good. Typically, the sediment may contain two-dimensional particles with a large number of layers, and the supernatant may contain two-dimensional particles with a small number of layers (for example, two-dimensional particles with a single layer or few layers).
　工程（ｅ）の洗浄処理は、例えば、工程（ｂ）と工程（ｃ）の間、工程（ｃ）と工程（ｄ）の間、工程（ｄ）の後の１以上の段階で実施してよく、工程（ｂ）と工程（ｃ）の間に実施することが好ましい。工程（ｂ）と工程（ｃ）の間に実施する場合、本工程における処理物をエッチング処理物と読み替え、工程（ｃ）と工程（ｄ）の間に実施する場合、本工程における処理物をインターカレーション処理物と読み替え、工程（ｄ）の後に実施する場合、本工程における処理物をデラミネーション処理物と読み替える。 The washing treatment of step (e) is performed, for example, at one or more stages between steps (b) and (c), between steps (c) and (d), and after step (d). It is often preferred to carry out between step (b) and step (c). When carried out between steps (b) and (c), the object to be processed in this step is read as an etching object, and when carried out between steps (c) and (d), the object to be processed in this step is In the case where intercalation treatment is performed after the step (d), the treatment in this step is read as delamination treatment.
　（実施形態３：材料）
　本実施形態の２次元粒子の用途として、２次元粒子を含む材料が挙げられる。 (Embodiment 3: Material)
Applications of the two-dimensional particles of this embodiment include materials containing two-dimensional particles.
　一態様において、上記２次元粒子を含む材料は、樹脂をさらに含んでいてもよい。かかる樹脂としては、アクリル樹脂、ポリエステル樹脂、ポリアミド樹脂、ポリオレフィン樹脂、ポリカーボネート樹脂、ポリウレタン樹脂、ポリスチレン樹脂、ポリエーテル樹脂、ポリ乳酸等が挙げられる。 In one aspect, the material containing the two-dimensional particles may further contain a resin. Examples of such resins include acrylic resins, polyester resins, polyamide resins, polyolefin resins, polycarbonate resins, polyurethane resins, polystyrene resins, polyether resins, and polylactic acid.
　一態様において、上記２次元粒子を含む材料は、分散媒体をさらに含んでいてもよい。かかる分散媒体としては、水；Ｎ－メチルピロリドン、Ｎ－メチルホルムアミド、Ｎ，Ｎ－ジメチルホルムアミド、メタノール、エタノール、ジメチルスルホキシド、エチレングリコール、酢酸等の有機系媒体等が挙げられる。 In one aspect, the material containing the two-dimensional particles may further contain a dispersion medium. Such dispersion media include water; organic media such as N-methylpyrrolidone, N-methylformamide, N,N-dimethylformamide, methanol, ethanol, dimethylsulfoxide, ethylene glycol and acetic acid.
　一態様において、上記２次元粒子を含む材料は、さらに粘度調整剤等の添加剤を含んでいてもよい。 In one aspect, the material containing the two-dimensional particles may further contain additives such as viscosity modifiers.
　上記２次元粒子を含む材料は、例えば、２次元粒子のみを含む材料；２次元粒子と樹脂とを含む材料；２次元粒子と分散媒体とを含む材料；２次元粒子と樹脂と分散媒体とを含む材料；２次元粒子と樹脂と分散媒体と添加剤とを含む材料であってよい。上記２次元粒子と樹脂とを含む材料、２次元粒子と樹脂と分散媒体とを含む材料、２次元粒子と樹脂と分散媒体と添加剤とを含む材料において、２次元粒子と樹脂とはコンポジットを形成していてもよい。 The material containing two-dimensional particles includes, for example, a material containing only two-dimensional particles; a material containing two-dimensional particles and a resin; a material containing two-dimensional particles and a dispersion medium; Material containing; may be a material containing two-dimensional particles, a resin, a dispersion medium, and an additive. In the material containing the two-dimensional particles and the resin, the material containing the two-dimensional particles, the resin, and the dispersion medium, and the material containing the two-dimensional particles, the resin, the dispersion medium, and the additive, the two-dimensional particles and the resin form a composite. may be formed.
　上記２次元粒子を含む材料における２次元粒子の含有率は、例えば１質量％以上１００質量％以下、さらに５０質量％以上１００質量％以下、とりわけ７０質量％以上１００質量％以下であってよい。 The content of the two-dimensional particles in the material containing the two-dimensional particles may be, for example, 1% by mass or more and 100% by mass or less, further 50% by mass or more and 100% by mass or less, and particularly 70% by mass or more and 100% by mass or less.
　上記材料は、導電性材料として好適である。 The above material is suitable as a conductive material.
　かかる２次元粒子を含む材料は、フィルムまたはペーストの形態であってよい。 A material containing such two-dimensional particles may be in the form of a film or paste.
　（実施形態４：フィルム）
　本実施形態の２次元粒子の用途として、２次元粒子を含むフィルムが挙げられる。かかるフィルムは、高い耐湿性を有するとともに、高い平滑性を有する。図２を参照して、本実施形態のフィルムを説明する。図２では、複数の２次元粒子１０が２次元面方向に配置され、且つ、２次元面方向に対して垂直な方向に積層している。図２では２次元粒子１０のみが積層して得られたフィルム３０を例示しているが、これに限定されない。 (Embodiment 4: Film)
Applications of the two-dimensional particles of the present embodiment include films containing two-dimensional particles. Such films have high moisture resistance and high smoothness. The film of this embodiment will be described with reference to FIG. In FIG. 2, a plurality of two-dimensional particles 10 are arranged in a two-dimensional plane direction and stacked in a direction perpendicular to the two-dimensional plane direction. Although FIG. 2 exemplifies the film 30 obtained by stacking only the two-dimensional particles 10, the present invention is not limited to this.
　かかるフィルムは、必要に応じて、上記樹脂および上記添加剤から選ばれる１種以上を含んでいてもよい。かかる樹脂は、フィルムにおいて、バインダとして機能しうる。 Such a film may contain one or more selected from the resins and additives described above, if necessary. Such resins can function as binders in films.
　一態様において、上記フィルムの導電率は、好ましくは２，０００Ｓ／ｃｍ以上、より好ましくは５，０００Ｓ／ｍ以上、さらに好ましくは１０，０００Ｓ／ｃｍ以上であり、例えば１００，０００Ｓ／ｃｍ以下、さらには５０，０００Ｓ／ｃｍ以下であってよい。 In one aspect, the conductivity of the film is preferably 2,000 S/cm or more, more preferably 5,000 S/m or more, still more preferably 10,000 S/cm or more, for example 100,000 S/cm or less, Furthermore, it may be 50,000 S/cm or less.
　本実施形態のフィルムの導電率は、フィルムの厚さと、４探針法で測定したフィルムの表面抵抗率を下記式に代入して求められる。
　導電率［Ｓ／ｃｍ］＝１／（フィルムの厚さ［ｃｍ］×フィルムの表面抵抗率［Ω／ｓｑ］） The electrical conductivity of the film of the present embodiment is obtained by substituting the thickness of the film and the surface resistivity of the film measured by the four-probe method into the following equation.
Conductivity [S / cm] = 1 / (film thickness [cm] × film surface resistivity [Ω / sq])
　上記フィルム（乾燥時）における２次元粒子の含有率は、好ましくは７０体積％以上１００体積％以下、更に好ましくは９０体積％以上１００体積％以下、より更に好ましくは９５体積％以上１００体積％以下であり、最も好ましくは１００体積％である。 The content of two-dimensional particles in the film (dry) is preferably 70% by volume or more and 100% by volume or less, more preferably 90% by volume or more and 100% by volume or less, and even more preferably 95% by volume or more and 100% by volume or less. and most preferably 100% by volume.
　上記フィルムは、例えば、２次元粒子と分散媒体と必要に応じて用いる上記樹脂とを含む混合液を吸引ろ過すること、または、２次元粒子と分散媒と必要に応じて用いる上記樹脂とを含む混合液を塗工し、分散媒を乾燥させることを１回または２回以上行うことにより製造しうる。
　上記分散媒としては、上記分散媒体と同様の媒体を用いることができ、例えば、水；Ｎ－メチルピロリドン、Ｎ－メチルホルムアミド、Ｎ，Ｎ－ジメチルホルムアミド、メタノール、エタノール、ジメチルスルホキシド、エチレングリコール、酢酸等の有機系媒体等が挙げられる。
　上記デラミネーション処理により得られた２次元粒子を含む上澄み液を、前記混合液として使用してもよい。 The film is formed, for example, by suction filtering a mixed liquid containing two-dimensional particles, a dispersion medium, and the resin used as necessary, or containing two-dimensional particles, a dispersion medium, and the resin used as necessary. It can be produced by applying the mixed liquid and drying the dispersion medium once or twice or more.
As the dispersion medium, the same medium as the dispersion medium can be used, such as water; N-methylpyrrolidone, N-methylformamide, N,N-dimethylformamide, methanol, ethanol, dimethylsulfoxide, ethylene glycol, Examples include organic media such as acetic acid.
A supernatant liquid containing two-dimensional particles obtained by the delamination treatment may be used as the mixed liquid.
　上記混合液を塗工する方法としては、例えば、スプレーにより塗工する方法が挙げられる。上記スプレーの方法は、例えば、エアレススプレー法またはエアースプレー法であってよく、具体的には、１流体ノズル、２流体ノズル、エアブラシ等のノズルを用いてスプレーする方法が挙げられる。 Examples of the method of applying the mixed liquid include a method of applying by spraying. The method of spraying may be, for example, an airless spray method or an air spray method, and specific examples include a method of spraying using a nozzle such as a one-fluid nozzle, a two-fluid nozzle, and an airbrush.
　上記フィルムは、導電性膜として好適である。 The above film is suitable as a conductive film.
　（実施形態５：ペースト）
　本実施形態の２次元粒子を用いた別の用途として、上記２次元粒子を含むペーストが挙げられる。かかるペーストも、高い耐湿性が求められる用途に適している。 (Embodiment 5: Paste)
Another application using the two-dimensional particles of this embodiment is a paste containing the two-dimensional particles. Such pastes are also suitable for applications requiring high moisture resistance.
　上記ペーストは、必要に応じ、上記樹脂、上記分散媒体および上記添加剤から選ばれる１種以上をさらに含んでいてもよい。 The paste may further contain one or more selected from the resin, the dispersion medium, and the additive, if necessary.
　上記ペーストにおける２次元粒子の含有率は、好ましくは３０質量％以上１００質量％以下、更に好ましくは５０質量％以上１００質量％以下、より更に好ましくは７０質量％以上１００質量％以下である。 The content of the two-dimensional particles in the paste is preferably 30% by mass or more and 100% by mass or less, more preferably 50% by mass or more and 100% by mass or less, and even more preferably 70% by mass or more and 100% by mass or less.
　上記ペーストは、２次元粒子と、必要に応じて用いる上記樹脂、上記分散媒体および上記添加剤とを混合することにより製造できる。 The paste can be produced by mixing the two-dimensional particles with the resin, the dispersion medium, and the additive used as necessary.
　上記ペーストは、導電性ペーストとして好適である。 The above paste is suitable as a conductive paste.
　（実施形態６：電極）
　本実施形態に係る電極は、上記フィルムを含む。かかる電極は、上記フィルムのみから形成されていてもよく、上記フィルムと、例えば、基材および保護層から選ばれる１種以上とを含んでいてもよい。 (Embodiment 6: Electrode)
The electrode according to this embodiment includes the above film. Such an electrode may be formed only from the above-mentioned film, or may contain the above-mentioned film and, for example, one or more selected from a substrate and a protective layer.
　本実施形態の電極は、上記フィルムを含んでいればよく、具体的な形態まで限定されない。電極は、固体状態のものから、フレキシブル性のある軟質状態のものまで挙げられる。 The electrode of the present embodiment is not limited to a specific form as long as it contains the above film. Electrodes include those in a solid state to those in a flexible soft state.
　本実施形態の電極において、上記フィルムは、測定対象物と直接接するように外気にさらされていてもよいし、基材、保護層等で覆われていてもよい。 In the electrode of the present embodiment, the film may be exposed to the open air so as to be in direct contact with the object to be measured, or may be covered with a base material, a protective layer, or the like.
　本実施形態の電極が基材を有する場合、上記フィルムと基材は直接接触していてもよい。基材の材質は、特に限定されず、例えば、セラミック、ガラス等の無機材料であってよく、有機材料であってよい。かかる有機材料として、例えば、フレキシブル有機材料が挙げられ、具体的には熱可塑性ポリウレタンエラストマー（ＴＰＵ）、ＰＥＴフィルム、ポリイミドフィルム等が挙げられる。また、基材の材質は、紙、布等の繊維材料（例えば、シート状繊維材料）であってよい。 When the electrode of this embodiment has a base material, the film and the base material may be in direct contact. The material of the substrate is not particularly limited, and may be, for example, an inorganic material such as ceramic or glass, or an organic material. Examples of such organic materials include flexible organic materials, and specific examples include thermoplastic polyurethane elastomers (TPU), PET films, polyimide films, and the like. Moreover, the material of the base material may be a fibrous material such as paper or cloth (for example, a sheet-like fibrous material).
（電極の用途）
　本実施形態の電極は、任意の適切な用途に利用されうる。例えば、電気化学測定をする際の対極や参照極、電気化学キャパシタ用電極、電池用電極、生体電極、センサ用電極、アンテナ用電極などが挙げられる。電磁シールド（ＥＭＩシールド）等、高い耐湿性（例えば、初期導電率の低下を低減し、酸化を防止すること）が要求されるような用途にも利用されうる。以下、これらの用途の詳細について説明する。 (Use of electrodes)
Electrodes of the present embodiments may be utilized for any suitable application. Examples include counter electrodes and reference electrodes for electrochemical measurements, electrodes for electrochemical capacitors, electrodes for batteries, bio-electrodes, electrodes for sensors, and electrodes for antennas. It can also be used in applications requiring high moisture resistance (eg, reducing initial conductivity loss and preventing oxidation) such as electromagnetic shielding (EMI shielding). Details of these applications are described below.
　電極は、特に限定されないが、例えばキャパシタ用電極、バッテリ用電極、生体信号センシング電極、センサ用電極、アンテナ用電極などでありうる。上記フィルムを使用することにより、より小さい容積（装置占有体積）でも、大容量のキャパシタおよびバッテリ、低インピーダンスの生体信号センシング電極、高感度のセンサおよびアンテナを得ることができる。 The electrodes are not particularly limited, but may be, for example, capacitor electrodes, battery electrodes, biosignal sensing electrodes, sensor electrodes, antenna electrodes, and the like. By using the film, it is possible to obtain a large-capacity capacitor and battery, a low-impedance biosignal sensing electrode, a highly sensitive sensor and an antenna, even with a smaller volume (equipment occupied volume).
　キャパシタは、電気化学キャパシタでありうる。電気化学キャパシタは、電極（電極活物質）と電解液中のイオン（電解質イオン）との間での物理化学反応に起因して発現する容量を利用したキャパシタであり、電気エネルギーを蓄えるデバイス（蓄電デバイス）として使用可能である。バッテリは、繰り返し充放電可能な化学電池でありうる。バッテリは、例えばリチウムイオンバッテリ、マグネシウムイオンバッテリ、リチウム硫黄バッテリ、ナトリウムイオンバッテリなどでありうるが、これらに限定されない。 The capacitor can be an electrochemical capacitor. An electrochemical capacitor is a capacitor that utilizes the capacity that is generated due to the physicochemical reaction between an electrode (electrode active material) and ions in an electrolyte (electrolyte ion). device). The battery can be a chemical cell that can be repeatedly charged and discharged. The battery can be, for example, but not limited to, a lithium-ion battery, a magnesium-ion battery, a lithium-sulfur battery, a sodium-ion battery, and the like.
　生体信号センシング電極は、生体信号を取得するための電極である。生体信号センシング電極は、例えばＥＥＧ（脳波）、ＥＣＧ（心電図）、ＥＭＧ（筋電図）、ＥＩＴ（電気インピーダンストモグラフィ）を測定するための電極でありうるが、これらに限定されない。 A biosignal sensing electrode is an electrode for acquiring biosignals. The biosignal sensing electrodes can be, but are not limited to, electrodes for measuring EEG (electroencephalogram), ECG (electrocardiogram), EMG (electromyography), EIT (electrical impedance tomography), for example.
　センサ用電極は、目的の物質、状態、異常等を検知するための電極である。センサは、例えばガスセンサ、バイオセンサ（生体起源の分子認識機構を利用した化学センサ）などでありうるが、これらに限定されない。 The sensor electrode is an electrode for detecting the target substance, state, abnormality, etc. The sensor can be, for example, a gas sensor, a biosensor (a chemical sensor that utilizes a biogenic molecular recognition mechanism), or the like, but is not limited to these.
　アンテナ用電極は、空間に電磁波を放射する、および／または、空間中の電磁波を受信するための電極である。アンテナ用電極が構成するアンテナは、携帯電話を始めとするモバイルコミュニケーション用のアンテナ（いわゆる３Ｇ、４Ｇ、５Ｇ用のアンテナ）や、ＲＦＩＤ用のアンテナ、あるいはＮＦＣ（Near Field Communication）用のアンテナなど特に限定されない。 The antenna electrode is an electrode for radiating electromagnetic waves into space and/or receiving electromagnetic waves in space. The antenna formed by the antenna electrode is an antenna for mobile communication such as a mobile phone (so-called 3G, 4G, 5G antenna), an RFID antenna, or an NFC (Near Field Communication) antenna. Not limited.
　本実施形態の電極は、好ましくはアンテナ用電極として用いられる。上記フィルムを含む電極は、高い耐湿性を有するとともに、フィルムとして高い平滑性を有する。このような特性を有する電極は通信距離を伸ばすうえで有利に用いることができる。 The electrode of this embodiment is preferably used as an antenna electrode. An electrode containing the film has high moisture resistance and high smoothness as a film. Electrodes having such characteristics can be advantageously used to extend the communication distance.
　以上、本開示の１つの実施形態における２次元粒子について詳述したが、種々の改変が可能である。なお、本開示の２次元粒子は、上述の実施形態における製造方法とは異なる方法によって製造されてもよく、また、本開示の２次元粒子の製造方法は、上述の実施形態における２次元粒子を提供するもののみに限定されないことに留意されたい。 Although the two-dimensional particles in one embodiment of the present disclosure have been described in detail above, various modifications are possible. Note that the two-dimensional particles of the present disclosure may be produced by a method different from the production method in the above-described embodiment, and the two-dimensional particle production method of the present disclosure is the same as the two-dimensional particles in the above-described embodiment. Note that you are not limited to just what you provide.
　以下の実施例により本開示を更に具体的に説明するが、本開示はこれらに限定されない。 The present disclosure will be described more specifically with the following examples, but the present disclosure is not limited to these.
［実施例１～２、比較例１～３］
〔２次元粒子の作製〕
　実施例１～２、比較例１～３では、以下に詳述する、（１）前駆体（ＭＡＸ）の準備、（２）前駆体のエッチング、（３）洗浄、（４）インターカレーション、（５）デラミネーション、を順に実施して、２次元粒子を作製した。 [Examples 1 and 2, Comparative Examples 1 and 3]
[Preparation of two-dimensional particles]
In Examples 1-2 and Comparative Examples 1-3, (1) preparation of the precursor (MAX), (2) etching of the precursor, (3) cleaning, (4) intercalation, and (5) Delamination was performed in order to prepare two-dimensional particles.
（１）前駆体（ＭＡＸ）の準備
　ＴｉＣ粉末、Ｔｉ粉末およびＡｌ粉末（いずれも株式会社高純度化学研究所製）を２：１：１のモル比で、ジルコニアボールを入れたボールミルに投入して２４時間混合した。得られた混合粉末をＡｒ雰囲気下にて１，３５０℃で２時間焼成した。得られた焼成体（ブロック）をエンドミルで最大寸法４０μｍ以下まで粉砕した。これにより、前駆体（ＭＡＸ）としてＴｉ３ＡｌＣ２粒子を得た。 (1) Precursor (MAX) preparation TiC powder, Ti powder and Al powder (all manufactured by Kojundo Chemical Laboratory Co., Ltd.) were placed in a ball mill containing zirconia balls at a molar ratio of 2:1:1. mixed for 24 hours. The obtained mixed powder was fired at 1,350° C. for 2 hours in an Ar atmosphere. The obtained sintered body (block) was pulverized with an end mill to a maximum size of 40 μm or less. This gave Ti 3 AlC 2 particles as a precursor (MAX).
（２）前駆体のエッチング
　上記方法で調製したＴｉ３ＡｌＣ２粒子（粉末）を用い、下記エッチング条件でエッチングを行って、Ｔｉ３ＡｌＣ２粉末に由来する固体成分を含む固液混合物（スラリー）を得た。
　（エッチング条件）
　・前駆体：Ｔｉ３ＡｌＣ２（目開き４５μｍふるい通し）
　・エッチング液組成：ＨＦ濃度　２．８ｍｏｌ／Ｌ
　　　　　　　　　　　ＨＩ濃度　５．６ｍｏｌ／Ｌ
　・前駆体投入量：３．０ｇ
　・エッチング容器：１００ｍＬアイボーイ
　・エッチング温度：３５℃
　・エッチング時間：２４時間
　・スターラー回転数：４００ｒｐｍ (2) Precursor etching Using the Ti 3 AlC 2 particles (powder) prepared by the above method, etching is performed under the following etching conditions to form a solid-liquid mixture (slurry) containing a solid component derived from the Ti 3 AlC 2 powder. got
(Etching conditions)
・Precursor: Ti 3 AlC 2 (through a 45 μm sieve)
・ Etching solution composition: HF concentration 2.8 mol / L
HI concentration 5.6mol/L
・ Precursor input amount: 3.0 g
・ Etching container: 100 mL eyeboy ・ Etching temperature: 35 ° C.
・Etching time: 24 hours ・Rotation speed of stirrer: 400 rpm
（３）洗浄
　上記スラリーを２分割して、５０ｍＬ遠沈管２本にそれぞれ挿入し、遠心分離機を用いて３５００Ｇの条件で５分間遠心分離を行った後、上澄み液を廃棄した。各遠沈管に純水３５ｍＬを追加し、再度３，５００Ｇで５分間遠心分離を行って上澄み液を分離除去する操作を１１回繰り返した。最終遠心分離後に、上澄み液を廃棄し、Ｔｉ３Ｃ２Ｔｓ－水分媒体クレイを得た。 (3) Washing The above slurry was divided into two, each inserted into two 50 mL centrifuge tubes, centrifuged at 3500 G for 5 minutes using a centrifuge, and then the supernatant was discarded. An operation of adding 35 mL of pure water to each centrifuge tube, performing centrifugation again at 3,500 G for 5 minutes, and separating and removing the supernatant was repeated 11 times. After the final centrifugation, the supernatant was discarded to obtain the Ti 3 C 2 T s -water medium clay.
（４）インターカレーション
　上記方法で調製したＴｉ３Ｃ２Ｔｓ－水分媒体クレイに対し、金属含有化合物としてＬｉＩを２．３７ｇと純水を３１．９ｇ添加した。インターカレーション処理後の上澄み液のｐＨが表１に示す値となるように、５８質量％ＨＩ水溶液を用いてｐＨを調整した後、２０℃以上２５℃以下で１５時間撹拌して、Ｌｉイオンをインターカレータとするインターカレーション処理を行った。インターカレーションの条件は以下の通りである。
　（インターカレーションの条件）
　・Ｔｉ３Ｃ２Ｔｓ－水分媒体クレイ（洗浄後ＭＸｅｎｅ）：固形分０．７５ｇ
　・金属含有化合物：ＬｉＩ　２．３７ｇ
　・インターカレーション容器：１００ｍＬアイボーイ
　・インターカレーション時液量：４０ｍＬ
　・温度：２０℃以上２５℃以下（室温）
　・時間：１５時間
　・スターラー回転数：８００ｒｐｍ (4) Intercalation To the Ti 3 C 2 T s -water-based clay prepared by the above method, 2.37 g of LiI as a metal-containing compound and 31.9 g of pure water were added. After adjusting the pH using a 58% by mass HI aqueous solution so that the pH of the supernatant after the intercalation treatment becomes the value shown in Table 1, the pH is stirred at 20 ° C. or higher and 25 ° C. or lower for 15 hours to obtain Li ions. was used as an intercalator. The conditions for intercalation are as follows.
(Conditions for intercalation)
Ti 3 C 2 T s -water-borne clay (MXene after washing): 0.75 g solids
・Metal-containing compound: LiI 2.37 g
・Intercalation container: 100 mL iboy ・Liquid volume during intercalation: 40 mL
・Temperature: 20°C or higher and 25°C or lower (room temperature)
・Time: 15 hours ・Rotation speed of stirrer: 800 rpm
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
（５）デラミネーション
　インターカレーションを行って得られたスラリーを、５０ｍＬ遠沈管に投入し、遠心分離機を用いて３，５００Ｇの条件で５分間遠心分離を行った後、上澄み液を廃棄した。さらに、純水４０ｍＬを追加してからシェーカーで１５分間撹拌後に、３，５００Ｇで５分間遠心分離し、上澄み液を２次元粒子含有液として回収する操作を、４回繰り返して、デラミネーション処理後の２次元粒子を含む上澄み液を得た。 (5) The slurry obtained by delamination intercalation was put into a 50 mL centrifuge tube, centrifuged at 3,500 G for 5 minutes using a centrifuge, and then the supernatant was discarded. . Furthermore, after adding 40 mL of pure water and stirring with a shaker for 15 minutes, the operation of centrifuging at 3,500 G for 5 minutes and collecting the supernatant liquid as a two-dimensional particle-containing liquid is repeated four times. A supernatant liquid containing two-dimensional particles of was obtained.
　上記デラミネーション処理後、以下の基準により、２次元粒子の単層化可否（単層化可能：〇、単層化不可：×）を評価した。単層化できていない２次元粒子は遠心分離機内で沈降し上澄み液に含まれなくなるためである。デラミネーション処理後の上澄み液中の２次元粒子の存在は、後述するフィルムの作製方法において、吸引ろ過後、用いたメンブレンフィルター上にフィルムが形成されているか否かにより確認した。
　〇　デラミネーション処理後の上澄み液中に２次元粒子が存在している
　×　デラミネーション処理後の上澄み液中に２次元粒子が存在しない After the delamination treatment, whether or not the two-dimensional particles could be formed into a single layer (Possible to form a single layer: ○, Not possible to form a single layer: ×) was evaluated according to the following criteria. This is because the two-dimensional particles that have not been formed into a monolayer settle in the centrifuge and are not included in the supernatant. The presence of two-dimensional particles in the supernatant liquid after the delamination treatment was confirmed by whether or not a film was formed on the membrane filter used after suction filtration in the film preparation method described below.
〇 Two-dimensional particles are present in the supernatant liquid after delamination treatment × No two-dimensional particles are present in the supernatant liquid after delamination treatment
（単層化率の測定方法）
　デラミネーション処理による単層化率は、上記デラネーション処理後の上澄み液中に含まれる２次元粒子の質量をＭ１、デラミネーション後に沈殿物として得られるものの質量をＭ２とし、Ｍ１をＭ１およびＭ２の合計で除した値（Ｍ１／（Ｍ１＋Ｍ２））として算出した。 (Method for measuring monolayer ratio)
The monolayer rate by the delamination treatment is defined as the mass of the two-dimensional particles contained in the supernatant after the delamination treatment is M 1 , the mass of the precipitate obtained after delamination is M 2 , and M 1 is M It was calculated as the value divided by the sum of 1 and M2 ( M1 /( M1 + M2 )).
（Ｌｉ原子含有率の測定方法）
　実施例および比較例で得られた２次元粒子（単層ＭＸｅｎｅ粒子）をアルカリ溶融法により溶液化して得られた溶液を、誘導結合プラズマ発光分光分析法（ＩＣＰ－ＡＥＳ）により測定し、２次元粒子に含まれるＬｉ原子を検出した。ＩＣＰ－ＡＥＳ測定には、サーモフィッシャーサイエンティフィック社製のｉＣＡＰ７４００を使用した。 (Method for measuring Li atom content)
A solution obtained by dissolving the two-dimensional particles (single-layer MXene particles) obtained in Examples and Comparative Examples by an alkali fusion method was measured by inductively coupled plasma atomic emission spectrometry (ICP-AES). Li atoms contained in the particles were detected. iCAP7400 manufactured by Thermo Fisher Scientific was used for ICP-AES measurement.
（Ｉ原子含有率の測定方法）
　実施例および比較例で得られた２次元粒子を燃焼イオンクロマトグラフ法により測定し、２次元粒子に含まれるＩ原子を検出した。燃焼イオンクロマトグラフ法により測定には、イサーモフィッシャーサイエンティフィック社製の燃焼イオンクトマトグラフィ装置Ｄｉｏｎｅｘ　ＩＣＳ－５０００を使用した。 (Method for measuring I atom content)
Two-dimensional particles obtained in Examples and Comparative Examples were measured by combustion ion chromatography to detect I atoms contained in the two-dimensional particles. Combustion ion chromatography device Dionex ICS-5000 manufactured by Ithermo Fisher Scientific was used for measurement by the combustion ion chromatography method.
　２次元粒子におけるＩ原子の含有率は、実施例１では０．７９質量％、実施例２では１．０４質量％、比較例１では０．６９質量％であった。
　実施例１、２の２次元粒子におけるＩ原子の含有率は、デラミネーション処理後の上澄み液から回収した２次元粒子について測定し、比較例１の２次元粒子におけるＩ原子の含有率は、デラミネーション処理後の沈降物について測定した。 The content of I atoms in the two-dimensional particles was 0.79% by mass in Example 1, 1.04% by mass in Example 2, and 0.69% by mass in Comparative Example 1.
The content of I atoms in the two-dimensional particles of Examples 1 and 2 was measured for the two-dimensional particles recovered from the supernatant liquid after the delamination treatment, and the content of I atoms in the two-dimensional particles of Comparative Example 1 was The sediment after lamination treatment was measured.
（フィルムの作製方法）
　実施例および比較例で得られたデラミネーション処理後の上澄み液を吸引ろ過し、８０℃で２４時間の真空乾燥を行って２次元粒子を含むフィルムを作製した。吸引ろ過のフィルターには、メンブレンフィルター（孔径０．２２ｕｍ）を用いた。 (Film production method)
Supernatants after the delamination treatment obtained in Examples and Comparative Examples were subjected to suction filtration and vacuum-dried at 80° C. for 24 hours to prepare films containing two-dimensional particles. A membrane filter (pore size: 0.22 μm) was used as a filter for suction filtration.
（７Ｌｉ　ＮＭＲ測定方法：第１成分および第２成分の定量）
　Ａｒ雰囲気（露点－６０℃未満）のグローブボックス内において、２次元粒子（単層ＭＸｅｎｅ粒子）と乾燥させたＡｌ２Ｏ３粉とを、質量比１：９で混合し、メノウ乳鉢で粉砕して、混合粉を得た。混合粉を、上記グローブボックス内において、外径４ｍｍの固体ＮＭＲ用ジルコニア製試料管に充填し、Ｋｅｌ－Ｆ製キャップをし、ＮＭＲ測定試料とした。２次元粒子（単層ＭＸｅｎｅ粒子）とＡｌ２Ｏ３粉とを合わせた試料の量は、２００ｍｇとした。 ( 7 Li NMR measurement method: quantification of the first component and the second component)
Two-dimensional particles (single-layer MXene particles) and dried Al 2 O 3 powder were mixed at a mass ratio of 1:9 in a glove box in an Ar atmosphere (dew point less than −60° C.) and pulverized in an agate mortar. to obtain a mixed powder. The mixed powder was packed in a zirconia sample tube for solid NMR with an outer diameter of 4 mm in the glove box, capped with a Kel-F cap, and used as a sample for NMR measurement. The amount of the sample, which is a combination of the two-dimensional particles (single-layer MXene particles) and the Al 2 O 3 powder, was 200 mg.
　７Ｌｉ　ＮＭＲ装置（分光計）として、Ｂｒｕｋｅｒ社製のＡＶＡＮＣＥ　ＩＩＩ　４００（磁場強度９．４Ｔ、７Ｌｉ核の共鳴周波数１５５．４５５ＭＨｚ）を用いた。プローブとしては、Ｂｒｕｋｅｒ社製のＰＨ　ＭＡＳ　４００Ｓ１　ＢＬ４　Ｎ－Ｐ／Ｈ　ＶＴＮを用いた。 As a 7 Li NMR apparatus (spectrometer), a Bruker AVANCE III 400 (magnetic field strength: 9.4 T, resonance frequency of 7 Li nucleus: 155.455 MHz) was used. As a probe, PH MAS 400S1 BL4 NP/H VTN manufactured by Bruker was used.
　以下の条件で７Ｌｉ　ＮＭＲ測定を実施し、１次元の７Ｌｉ　ＮＭＲスペクトルを得た。
　測定法：マジック角回転＋シングルパルス法
　マジック角回転速度：１５ｋＨｚ
　パルス強度：２８～５６ｋＨｚ（出力は１００Ｗに固定）
　パルスフリップ角：９０°
　積算遅延時間：４秒
　積算回数：１，０２４回 7 Li NMR measurement was performed under the following conditions to obtain a one-dimensional 7 Li NMR spectrum.
Measurement method: Magic angle rotation + single pulse method Magic angle rotation speed: 15 kHz
Pulse intensity: 28-56kHz (output fixed at 100W)
Pulse flip angle: 90°
Integration delay time: 4 seconds Integration count: 1,024 times
　得られた７Ｌｉ　ＮＭＲスペクトルに対し、２成分のローレンツ曲線で回帰し、各ピークの化学シフト値および相対面積を求めた。基準物質は、１ｍｏｌ／Ｌ　ＬｉＣｌ水溶液におけるＬｉとした。Ｌｉの回帰計算、化学シフト値および相対面積の算出には、Ｂｒｕｋｅｒ社製ＮＭＲコンソールソフトウェア付属のスペクトルフィッティング機能を用いた。化学シフト値から、第１成分、第２成分のそれぞれに帰属されるピークを特定し、第１成分に帰属されるピークの相対面積Ｓ１および第２成分に帰属されるピークの相対面積Ｓ２から、第１成分の割合（原子基準）を、Ｓ１／（Ｓ１＋Ｓ２）として算出した。 The resulting 7 Li NMR spectrum was regressed with a two-component Lorenz curve to determine the chemical shift value and relative area of each peak. The reference substance was Li in a 1 mol/L LiCl aqueous solution. The spectral fitting function attached to Bruker's NMR console software was used for Li regression calculation, chemical shift value and relative area calculation. From the chemical shift value, the peaks attributed to each of the first component and the second component are identified, and the relative area S 1 of the peak attributed to the first component and the relative area S 2 of the peak attributed to the second component are determined. , the ratio of the first component (atomic basis) was calculated as S 1 /(S 1 +S 2 ).
（フィルム導電率測定方法）
　得られた２次元粒子を含むフィルムについて、１サンプルにつき３箇所で、表面抵抗率（Ω／ｓｑ）および厚さ（μｍ）を測定し、以下の計算式により導電率（Ｓ／ｃｍ）を算出した。
　　体積抵抗率（Ω・ｃｍ）＝表面抵抗率（Ω／ｓｑ）×厚さ（μｍ）×１０４
　　導電率（Ｓ／ｃｍ）＝１÷体積抵抗率（Ω・ｃｍ）
　得られた３つの導電率の平均値を、２次元粒子を含むフィルムの導電率として採用した。抵抗率測定には、簡易型低抵抗率計（株式会社三菱ケミカルアナリティック製、ロレスタＡＸ　ＭＣＰ－Ｔ３７０）を用い、フィルムの表面抵抗を４端子法にて測定した。厚さ測定には、マイクロメーター（株式会社ミツトヨ製、ＭＤＨ－２５ＭＢ）を用いた。 (Film conductivity measurement method)
For the obtained film containing two-dimensional particles, the surface resistivity (Ω/sq) and thickness (μm) were measured at three points per sample, and the electrical conductivity (S/cm) was calculated by the following formula. did.
Volume resistivity (Ω cm) = surface resistivity (Ω/sq) x thickness (μm) x 10 4
Conductivity (S/cm) = 1/volume resistivity (Ω cm)
The average of the three conductivity values obtained was adopted as the conductivity of the film containing the two-dimensional particles. A simple low resistivity meter (Loresta AX MCP-T370, manufactured by Mitsubishi Chemical Analytic Co., Ltd.) was used to measure the resistivity, and the surface resistance of the film was measured by the four-probe method. A micrometer (MDH-25MB manufactured by Mitutoyo Co., Ltd.) was used to measure the thickness.
（導電率維持率測定方法）
　作製したフィルムについて、上記方法によりフィルム導電率を測定してＥ０とし、相対湿度９９％温度２５℃の恒温恒湿槽内に１４日間静置した。その後、フィルム導電率を再度測定し、Ｅとした。ＥをＥ０で除した値を導電率維持率とした。 (Conductivity retention rate measurement method)
The film conductivity of the produced film was measured by the method described above to obtain E 0 , and the film was allowed to stand in a constant temperature and humidity chamber at a relative humidity of 99% and a temperature of 25° C. for 14 days. After that, the film conductivity was measured again and designated as E. The value obtained by dividing E by E0 was defined as the electrical conductivity retention rate.
　結果を表２に示す。
　なお、比較例１では、単層化不可であり、フィルムが得られなかったため、７Ｌｉ　ＮＭＲ測定、導電率測定および導電率維持率測定を行っていない。 Table 2 shows the results.
In Comparative Example 1, since a single layer could not be formed and no film was obtained, 7 Li NMR measurement, conductivity measurement, and conductivity retention rate measurement were not performed.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　以上より、実施例１、２で得られた２次元粒子を含むフィルムは、単層化が可能であって、耐湿試験後も導電率が維持され、耐湿性が良好であった。一方、比較例２～３の２次元粒子では、Ｌｉ原子の第１成分と第２成分の合計における第１成分の割合が、５５原子％未満であり、かかる２次元粒子を含むフィルムは、耐湿試験後に導電率が低下し、耐湿性が十分に満足できるものではなかった。 As described above, the films containing the two-dimensional particles obtained in Examples 1 and 2 were capable of forming a single layer, maintained electrical conductivity even after the moisture resistance test, and had good moisture resistance. On the other hand, in the two-dimensional particles of Comparative Examples 2 and 3, the ratio of the first component to the total of the first component and the second component of Li atoms is less than 55 atomic %, and the film containing such two-dimensional particles is moisture resistant. The electrical conductivity decreased after the test, and the moisture resistance was not fully satisfactory.
　　１ａ、１ｂ　層本体（ＭｍＸｎ層）
　　３ａ、５ａ、３ｂ、５ｂ　修飾または終端Ｔ
　　７ａ、７ｂ　ＭＸｅｎｅ層
　　１０、１０ａ、１０ｂ　ＭＸｅｎｅ粒子（層状材料の２次元粒子） 1a, 1b layer body (M m X n layer)
3a, 5a, 3b, 5b modified or terminated T
7a, 7b MXene layers 10, 10a, 10b MXene particles (two-dimensional particles of layered material)

Claims (7)

  1. 　１つまたは複数の層を有する２次元粒子であって、
    　Ｌｉ原子およびＩ原子を含み、
    　前記層が、以下の式：
    　　ＭｍＸｎ
    　（式中、Ｍは、少なくとも１種の第３、４、５、６、７族金属であり、
    　　Ｘは、炭素原子、窒素原子またはそれらの組み合わせであり、
    　　ｎは、１以上４以下であり、
    　　ｍは、ｎより大きく、５以下である）
    で表される層本体と、該層本体の表面に存在する修飾または終端Ｔ（Ｔは、水酸基、フッ素原子、塩素原子、酸素原子および水素原子からなる群より選択される少なくとも１種である）とを含み、
    　Ｌｉ原子は、第１成分と、前記第１成分よりも、７Ｌｉ　ＮＭＲにより測定される化学シフトが大きい第２成分とを含み、
    　前記第１成分と前記第２成分の合計における、前記第１成分の割合は、５５原子％以上である、２次元粒子。     A two-dimensional particle having one or more layers,
    containing Li atoms and I atoms,
    The layer has the following formula:
    M m X n
    (wherein M is at least one Group 3, 4, 5, 6, 7 metal;
    X is a carbon atom, a nitrogen atom, or a combination thereof;
    n is 1 or more and 4 or less,
    m is greater than n and less than or equal to 5)
    and a modification or termination T (T is at least one selected from the group consisting of a hydroxyl group, a fluorine atom, a chlorine atom, an oxygen atom and a hydrogen atom) present on the surface of the layer body represented by and
    Li atoms include a first component and a second component having a larger chemical shift as measured by 7 Li NMR than the first component,
    Two-dimensional particles, wherein the proportion of the first component in the total of the first component and the second component is 55 atomic % or more.
  2. 　前記Ｉ原子の含有率が、０．２質量％以上１．５質量である、請求項１に記載の２次元粒子。 The two-dimensional particle according to claim 1, wherein the content of the I atom is 0.2% by mass or more and 1.5% by mass.
  3. 　前記Ｌｉ原子の含有率が、０．１質量％以上２０質量％以下である、請求項１または２に記載の２次元粒子。 The two-dimensional particle according to claim 1 or 2, wherein the Li atom content is 0.1% by mass or more and 20% by mass or less.
  4. 　（ａ）以下の式：
    　　ＭｍＡＸｎ
    　（式中、Ｍは、少なくとも１種の第３、４、５、６、７族金属であり、
    　　Ｘは、炭素原子、窒素原子またはそれらの組み合わせであり、
    　　Ａは、少なくとも１種の第１２、１３、１４、１５、１６族元素であり、
    　　ｎは、１以上４以下であり、
    　　ｍは、ｎより大きく、５以下である）
    で表される前駆体を準備すること、
    　（ｂ）エッチング液を用いて、前記前駆体からＡ原子の少なくとも一部をエッチングにより除去して、エッチング処理物を得ること、
    　（ｃ）金属イオンを含む金属含有化合物を用いて、分散媒体中で、前記エッチング処理物に対してインターカレーション処理を行って、インターカレーション処理物を得ること、および、
    　（ｄ）前記インターカレーション処理物に対してデラミネーション処理を行って、２次元粒子を得ること、を含み、
    　前記エッチング液は、ＨＦおよびＨＩを含み、
    　前記金属含有化合物は、Ｌｉ塩を含み、
    　前記分散媒体のｐＨは、０．６以上１．８以下である、２次元粒子の製造方法。     (a) the following formula:
    M m AX n
    (wherein M is at least one Group 3, 4, 5, 6, 7 metal;
    X is a carbon atom, a nitrogen atom, or a combination thereof;
    A is at least one Group 12, 13, 14, 15, 16 element;
    n is 1 or more and 4 or less,
    m is greater than n and less than or equal to 5)
    preparing a precursor represented by
    (b) using an etchant to etch away at least a portion of the A atoms from the precursor to obtain an etched product;
    (c) using a metal-containing compound containing metal ions to intercalate the etched product in a dispersion medium to obtain an intercalated product;
    (d) subjecting the intercalated product to a delamination treatment to obtain two-dimensional particles;
    The etchant contains HF and HI,
    The metal-containing compound comprises a Li salt,
    The method for producing two-dimensional particles, wherein the dispersion medium has a pH of 0.6 or more and 1.8 or less.
  5. 　前記２次元粒子は、Ｌｉ原子を含み、
    　前記Ｌｉ原子は、第１成分と、前記第１成分よりも、７Ｌｉ　ＮＭＲにより測定される化学シフトが大きい第２成分とを含み、
    　前記第１成分と前記第２成分の合計における、前記第１成分の割合は、５５原子％以上である、請求項４に記載の２次元粒子の製造方法。     The two-dimensional particles contain Li atoms,
    The Li atoms include a first component and a second component having a larger chemical shift as measured by 7 Li NMR than the first component,
    5. The method for producing two-dimensional particles according to claim 4, wherein the ratio of said first component to the total of said first component and said second component is 55 atomic % or more.
  6. 　請求項１～３のいずれか１項に記載の２次元粒子を含む材料であって、
    　フィルムまたはペーストの形態である、材料。     A material comprising the two-dimensional particles according to any one of claims 1 to 3,
    A material that is in the form of a film or paste.
  7. 　さらに樹脂を含む、請求項６に記載の材料。 The material according to claim 6, further containing resin.
PCT/JP2022/046436 2022-02-28 2022-12-16 Two-dimensional particle, method for producing two-dimensional particle, and material WO2023162423A1 (en)

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Publication number Priority date Publication date Assignee Title
JP2020093971A (en) * 2018-10-02 2020-06-18 コリア・インスティテュート・オブ・サイエンス・アンド・テクノロジー 2-dimensional mxene particle surface-modified with functional group containing saturated or unsaturated hydrocarbon, preparation method thereof and use thereof
WO2022030444A1 (en) * 2020-08-03 2022-02-10 株式会社村田製作所 Conductive composite material
WO2022050191A1 (en) * 2020-09-02 2022-03-10 株式会社村田製作所 Conductive two-dimensional particles and method for producing same
WO2022050114A1 (en) * 2020-09-02 2022-03-10 株式会社村田製作所 Electroconductive two-dimensional particles and method for manufacturing same
WO2022080321A1 (en) * 2020-10-15 2022-04-21 株式会社村田製作所 Electroconductive two-dimensional particles, method for producing same, electroconductive film, electroconductive composite material and electroconductive paste

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2020093971A (en) * 2018-10-02 2020-06-18 コリア・インスティテュート・オブ・サイエンス・アンド・テクノロジー 2-dimensional mxene particle surface-modified with functional group containing saturated or unsaturated hydrocarbon, preparation method thereof and use thereof
WO2022030444A1 (en) * 2020-08-03 2022-02-10 株式会社村田製作所 Conductive composite material
WO2022050191A1 (en) * 2020-09-02 2022-03-10 株式会社村田製作所 Conductive two-dimensional particles and method for producing same
WO2022050114A1 (en) * 2020-09-02 2022-03-10 株式会社村田製作所 Electroconductive two-dimensional particles and method for manufacturing same
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