WO2021200177A1 - Nanodiamond aqueous dispersion composition, negative electrode paste, negative electrode, and lithium-ion secondary cell - Google Patents

Nanodiamond aqueous dispersion composition, negative electrode paste, negative electrode, and lithium-ion secondary cell Download PDF

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WO2021200177A1
WO2021200177A1 PCT/JP2021/010941 JP2021010941W WO2021200177A1 WO 2021200177 A1 WO2021200177 A1 WO 2021200177A1 JP 2021010941 W JP2021010941 W JP 2021010941W WO 2021200177 A1 WO2021200177 A1 WO 2021200177A1
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negative electrode
aqueous dispersion
ion secondary
nanodiamond
particles
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French (fr)
Japanese (ja)
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彩乃 三木
篤史 久米
山岸　学
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株式会社ダイセル
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/139—Processes of manufacture
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present invention relates to a nanodiamond aqueous dispersion composition, a negative electrode paste, a negative electrode and a lithium ion secondary battery.
  • nanodiamond may be referred to as "ND”.
  • the negative electrode used in a lithium ion secondary battery is generally composed mainly of a negative electrode active material layer and a current collector.
  • the negative electrode active material layer is obtained by applying a negative electrode paste containing a negative electrode active material and a binder to the surface of a current collector such as a copper foil and drying the negative electrode active material layer.
  • Non-Patent Document 1 discloses that urea and acid are mixed with detonation nanodiamond, heat-treated with microwaves, annealed, carbonized at a high temperature under an argon atmosphere, and a negative electrode is prepared using graphene nanosheets. doing.
  • Patent Document 1 discloses a lithium ion battery using nanodiamonds that have been made conductive by an ion implantation method.
  • An object of the present invention is to provide a negative electrode for a lithium ion secondary battery having improved performance and a lithium ion secondary battery using the negative electrode.
  • the present invention provides the following nanodiamond aqueous dispersion composition, negative electrode paste, negative electrode and lithium ion secondary battery.
  • Nanodiamond aqueous dispersion in which nanodiamond (ND) particles are dispersed in an aqueous solvent containing a thickener, wherein the average dispersed particle size of the ND particles is 5 to 100 nm.
  • Composition [2] The nanodiamond aqueous dispersion composition according to [1], wherein the primary particles of nanodiamond are spherical, ellipsoidal or polyhedral.
  • a negative electrode paste for a lithium ion secondary battery which comprises the nanodiamond aqueous dispersion composition according to any one of [1] to [4], a negative electrode active material, and a binder.
  • a negative electrode for a lithium ion secondary battery which is produced by using the negative electrode paste according to [5].
  • a lithium ion secondary battery comprising the negative electrode, the positive electrode, and the electrolyte according to [6].
  • ND is highly dispersed in the negative electrode, it is possible to provide a lithium ion secondary battery in which performance such as battery capacity and cycle characteristics is improved by adding a small amount of ND.
  • the average dispersed particle size of ND particles is 210.40 nm, and although a certain dispersibility of ND particles can be seen, local agglomerates are also confirmed and the dispersibility is poor. I was suspected.
  • an ND aqueous dispersion composition contains ND particles, a thickener and an aqueous solvent.
  • the ND particles contained in the ND aqueous dispersion composition may contain ND primary particles, but exist as agglomerates in which a plurality of ND primary particles are aggregated.
  • the thickener is not particularly limited as long as it improves the coatability of the negative electrode paste obtained by using the ND aqueous dispersion composition on the current collector.
  • the thickener include cellulose-based polymers such as carboxymethyl cellulose, methyl cellulose, and hydroxypropyl cellulose, ammonium salts or alkali metal salts of these cellulose-based polymers, polycarboxylic acids or salts thereof, polyethylene oxide, polyvinylpyrrolidone, and polyvinyl alcohol. , Poly (meth) acrylic acid alkali metal salt (for example, sodium salt) and other water-soluble polymers such as poly (meth) acrylate.
  • cellulose-based polymers, ammonium salts of cellulose-based polymers, and alkali metal salts of cellulose-based polymers are preferable, and carboxymethyl cellulose, ammonium salts of carboxymethyl cellulose, and alkali metal salts of carboxymethyl cellulose (sodium salt, potassium salt, lithium salt) are preferable. More preferably, the sodium salt of carboxymethyl cellulose (CMC) is particularly preferred.
  • the aqueous solvent is not particularly limited as long as the ND particles can be dispersed, but distilled water, ion-exchanged water, city water, and industrial water are preferable, and water-water miscible solvents (methanol, ethanol, propanol, acetone, THF, etc. It may be a water-containing solvent containing DMF, DMSO, acetonitrile, etc.).
  • the primary particles of ND are preferably spherical, ellipsoidal or polyhedral, and more preferably spherical.
  • the ND is preferably an ND produced by the detonation method.
  • the average particle size of the ND primary particles is preferably about 1 to 10 nm, more preferably about 4 to 6 nm.
  • the average particle size of the ND primary particles is measured by small-angle X-ray scattering measurement (SAXS method) using an X-ray diffractometer (trade name "SmartLab”, manufactured by Rigaku Co., Ltd.), and particle size distribution analysis software (Sanx method). It can be determined by estimating the primary particle size of nanodiamonds in the region of scattering angle 1 ° to 3 ° using the trade name "NANO-Solver” (manufactured by Rigaku Co., Ltd.).
  • the average particle size of the ND primary particles can be obtained by Scherrer's formula from the analysis result of the powder X-ray diffraction method (XRD).
  • XRD powder X-ray diffraction method
  • Examples of the XRD measuring device include a fully automatic multipurpose X-ray diffractometer (manufactured by Rigaku Co., Ltd.).
  • the zeta potential of the ND particles contained in the ND aqueous dispersion composition is preferably ⁇ 20 to ⁇ 80 mV, more preferably ⁇ 40 to ⁇ 60 mV.
  • the zeta potential of the ND particles contained in the ND aqueous dispersion composition can be measured by a laser Doppler electrophoresis method using an apparatus manufactured by Malvern (trade name "Zetasizer Nano ZS").
  • the ND aqueous dispersion composition to be measured is diluted with ultrapure water so that the ND particle concentration becomes 0.2% by mass, and then subjected to ultrasonic irradiation with an ultrasonic cleaner, and zeta potential measurement is performed.
  • the temperature is 25 ° C.
  • the ND primary particles are preferably those that have been surface-modified with oxygen oxidation treatment or a hydrophilic polymer.
  • the nanodiamond obtained by the detonation method is obtained as an aggregate of primary particles, but since this aggregate contains primary particles, the concept of including ND primary particles and ND aggregates is described below. It may be described as "ND powder”.
  • the oxygen oxidation treatment can be carried out by heating the ND powder in a gas atmosphere having a predetermined composition containing oxygen using a gas atmosphere furnace.
  • ND powder is arranged in a gas atmosphere furnace, oxygen-containing gas is supplied or passed through the furnace, and the temperature inside the furnace is raised to the temperature condition set as the heating temperature to obtain oxygen. Oxidation treatment is carried out.
  • the oxygen oxidation treatment can be carried out under conditions such that the dispersed particle size of the ND particles in the ND aqueous dispersion composition of the present invention is within a predetermined range.
  • the temperature condition of the oxygen oxidation treatment is, for example, 250 to 500 ° C.
  • the temperature condition of this oxygen oxidation treatment is preferably relatively high temperature, for example, 400 to 450 ° C.
  • the oxygen-containing gas is a mixed gas containing an inert gas in addition to oxygen. Examples of the inert gas include nitrogen, argon, carbon dioxide, and helium.
  • the oxygen concentration of the mixed gas is, for example, 1 to 35% by volume.
  • Hydrophilic polymers used for surface modification include polyglycerin, polyvinylpyrrolidone, polyethylene glycol, polyvinyl alcohol, poly (meth) acrylic acid, polyacrylamide, polyethyleneimine, vinyl ether-based polymers, cellulose derivatives, and water-soluble polyesters. Examples include natural high molecular weight polysaccharides.
  • the vinyl ether-based polymer include simple or copolymers such as alkyl vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, vinyl isopropyl ether, vinyl butyl ether, and vinyl isobutyl ether (for example, polyvinyl methyl ether, polyvinyl ethyl ether, and vinyl ether-.
  • cellulose derivative examples include methyl cellulose, ethyl cellulose, propyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxyethyl methyl cellulose, hydroxypropyl methyl cellulose, carboxymethyl cellulose, carboxyethyl cellulose and the like.
  • water-soluble polyester examples include polydimethylolpropionic acid ester.
  • the natural high molecular weight polysaccharide include alginic acid or a salt thereof, pectin, starch, agar, gum arabic, dextrin, carrageenan and the like.
  • Preferred hydrophilic polymers are polyglycerin, polyvinylpyrrolidone, polyethylene glycol, polyvinyl alcohol and poly (meth) acrylic acid, with polyglycerin being particularly preferred.
  • the surface groups (OH, NH 2 , COOH, etc.) of the ND particles and the hydrophilic polymer are covalently bonded to each other.
  • Modification of the ND particles with a hydrophilic polymer can be carried out according to a conventional method such as a method using a catalyst such as an acid, a method of heating and dehydrating and condensing, and a method of using a dehydration condensing agent.
  • the average dispersed particle size of the ND particles in the dispersion liquid of the present invention is preferably about 5 to 100 nm, more preferably about 5 to 50 nm. If the average dispersed particle size of the ND particles exceeds 100 nm, the effect of adding ND becomes low, which is not preferable.
  • the average dispersed particle size may be measured by a transmission electron microscope (TEM) or a dynamic light scattering method (DLS).
  • the concentration of ND particles in the nanodiamond aqueous dispersion composition is preferably about 0.1 to 1.0% by mass, more preferably about 0.1 to 0.5% by mass.
  • the concentration of the thickener in the nanodiamond aqueous dispersion composition is preferably about 0.1 to 5.0% by mass, more preferably about 0.1 to 3.0% by mass.
  • the mass ratio of the ND particles to the thickener (mass of the ND particles / mass of the thickener) in the nanodiamond aqueous dispersion composition is preferably about 0.1 to 1.0, more preferably 0.1 to 0. It is about 5.
  • Another embodiment of the present invention is a negative electrode paste for a lithium ion secondary battery containing the above-mentioned ND aqueous dispersion composition, a negative electrode active material, and a binder.
  • the negative electrode active material is not particularly limited as long as it is a normal negative electrode active material that can be used for the negative electrode of a lithium ion secondary battery.
  • carbon materials such as natural graphite, artificial graphite, resin charcoal, carbon fiber, activated charcoal, hard carbon, and soft carbon; lithium-based metals such as lithium metal and lithium alloy; metals such as silicon and tin; polyacene, polyacetylene, polypyrrole, etc.
  • Examples include the conductive polymer of.
  • a carbon material is preferable, and a graphite material such as natural graphite or artificial graphite is particularly preferable.
  • the graphitic material is not particularly limited as long as it is an ordinary graphitic material that can be used for the negative electrode of a lithium ion secondary battery.
  • Examples thereof include artificial graphite produced by heat-treating natural graphite, petroleum-based and coal-based coke.
  • natural graphite refers to graphite naturally produced as an ore.
  • the production area, properties, and type of natural graphite used as the core material of the present embodiment are not particularly limited.
  • Artificial graphite refers to graphite made by an artificial method and graphite that is close to a perfect crystal of graphite.
  • Such artificial graphite can be obtained, for example, by using tar or coke obtained from dry distillation of coal, residue obtained by distillation of crude oil, or the like as a raw material, and undergoing a firing step and a graphitization step.
  • the graphite material has graphite powder as a core material, and at least a part of the surface of the graphite powder is coated with a carbon material having a lower crystallinity than the graphite powder (hereinafter, also referred to as surface-coated graphite). preferable.
  • a carbon material having a lower crystallinity than the graphite powder hereinafter, also referred to as surface-coated graphite.
  • the edge portion of the graphite powder is coated with the above carbon material.
  • the binding property with the binder can be improved as compared with the case of graphite alone, so that the amount of the binder can be reduced. As a result, the battery characteristics of the obtained lithium ion secondary battery can be improved.
  • the carbon material having a lower crystallinity than the graphite powder is, for example, amorphous carbon such as soft carbon and hard carbon.
  • graphite powder used as a core material examples include natural graphite, artificial graphite produced by heat-treating petroleum-based and coal-based coke.
  • these graphite powders may be used alone or in combination of two or more.
  • natural graphite is preferable from the viewpoint of cost.
  • the surface-coated graphite according to the present embodiment is obtained by mixing an organic compound which is carbonized by a firing step to become a carbon material having a lower crystallinity than the graphite powder and the graphite powder, and then the organic compound is calcined and carbonized. It can be produced by.
  • the organic compound to be mixed with the graphite powder is not particularly limited as long as it can be carbonized by firing to obtain a carbon material having a lower crystallinity than the graphite powder.
  • Tar Pitch of petroleum-based pitch, pitch of coal-based pitch, etc .
  • Thermoplastic resin such as polyvinyl chloride, polyvinyl acetate, polyvinyl butyral, polyvinyl alcohol, polyvinylidene chloride, polyacrylonitrile; Thermosetting resin such as phenol resin, furfuryl alcohol resin, etc.
  • Resins natural resins such as cellulose; aromatic hydrocarbons such as naphthalene, alkylnaphthalene, and anthracene can be mentioned.
  • these organic compounds may be used alone or in combination of two or more. Moreover, these organic compounds may be used by being dissolved or dispersed with a solvent, if necessary.
  • tar and pitch are preferable from the viewpoint of price.
  • the average particle size in the volume-based particle size distribution measured by the laser diffraction / scattering particle size distribution measurement method for the negative electrode active material is not particularly limited, but is preferably 5 to 100 ⁇ m, more preferably 5 to 50 ⁇ m.
  • the average particle size of the negative electrode active material can be measured by, for example, a dynamic light scattering method (DLS), a laser diffraction scattering type particle size distribution measurement method, or the like.
  • the amount of the negative electrode active material used is preferably 60 to 90% by mass, more preferably 80 to 90% by mass, based on the solid content of the negative electrode paste.
  • the binder contained in the negative electrode paste of the present invention is not particularly limited as long as it can form an electrode and has sufficient electrochemical stability, and is not particularly limited, but for example, polyacrylic acid, polytetrafluoroethylene, and polyvinylidene fluoride. , Styrene-butadiene rubber (SBR), polyimide and the like.
  • SBR Styrene-butadiene rubber
  • the binder may be used alone or in combination of two or more. Among these, styrene-butadiene rubber is preferable.
  • the amount of the binder used is preferably 0.5 to 3.0% by mass, more preferably 0.5 to 1.0% by mass, based on the solid content of the negative electrode paste.
  • the negative electrode paste of the present invention contains an aqueous solvent.
  • aqueous solvent those exemplified in the ND aqueous dispersion composition can be used.
  • the amount of the aqueous solvent used is preferably 30 to 70% by mass, more preferably 40 to 60% by mass, based on the total amount of the negative electrode paste.
  • a conductive auxiliary agent may be further added to the negative electrode paste for a lithium ion secondary battery of the present invention.
  • the conductive auxiliary agent is not particularly limited as long as it has electron conductivity and improves the conductivity of the electrode, and examples thereof include acetylene black, ketjen black, carbon black, and carbon nanofibers. These conductive auxiliaries may be used alone or in combination of two or more.
  • the amount of the conductive auxiliary agent used is preferably 1.0 to 15% by mass, more preferably 1.0 to 5.0% by mass, based on the solid content of the negative electrode paste.
  • the negative electrode of the present invention can be obtained by applying the negative electrode paste of the present invention on a current collector and drying it.
  • a known method can be used, for example, a reverse roll method, a direct roll method, a doctor blade method, a knife method, an extrusion method, a curtain method, a gravure method, and a bar. Examples include the method, the dip method and the squeeze method.
  • the negative electrode paste may be applied to only one side of the current collector or to both sides. When it is applied to both sides of the current collector, it may be applied sequentially on one side or at the same time on both sides.
  • the thickness, length and width of the coating layer can be appropriately determined according to the size of the battery.
  • a method for drying the applied negative electrode paste As a method for drying the applied negative electrode paste, a generally known method can be used. In particular, it is preferable to use hot air, vacuum, infrared rays, far infrared rays, electron beams and low temperature air alone or in combination.
  • the drying temperature is not particularly limited, but is, for example, 60 to 80 ° C.
  • the current collector used for manufacturing the negative electrode is not particularly limited as long as it is a normal current collector that can be used for a lithium ion secondary battery, but from the viewpoint of price, availability, electrochemical stability, etc. Copper is preferred.
  • the shape of the current collector is also not particularly limited, but for example, a foil-like current collector having a thickness of 15 to 20 ⁇ m can be used.
  • the negative electrode for the lithium ion secondary battery according to the present embodiment may be pressed if necessary.
  • a pressing method a generally known method can be used. For example, a die pressing method, a calendar pressing method, and the like can be mentioned.
  • the lithium ion secondary battery of the present invention preferably includes the above-mentioned negative electrode for a lithium ion secondary battery, an electrolyte, a positive electrode, and further includes a separator.
  • the lithium ion secondary battery according to this embodiment can be manufactured according to a known method.
  • the electrode for example, a laminated body or a wound body can be used.
  • the exterior body a metal exterior body or an aluminum laminated exterior body can be appropriately used.
  • the shape of the battery may be any of coin type, button type, sheet type, cylindrical type, square type, flat type and the like.
  • the positive electrode active material used for the positive electrode of the lithium ion secondary battery of the present invention is appropriately selected according to the application, but the lithium ions can be reversibly released and occluded, and the electron conductivity is high so that electron transport can be easily performed.
  • the material is preferred.
  • composite oxides of lithium and transition metals such as lithium nickel composite oxides, lithium cobalt composite oxides, lithium manganese composite oxides, lithium-manganese-nickel composite oxides; transitions of TiS 2 , FeS, MoS 2, etc.
  • Metal sulfides; transition metal oxides such as MnO, V 2 O 5 , V 6 O 13 , TiO 2 , olivine type lithium phosphorus oxide and the like can be mentioned.
  • the olivine-type lithium phosphorus oxide is, for example, at least one of the group consisting of Mn, Cr, Co, Cu, Ni, V, Mo, Ti, Zn, Al, Ga, Mg, B, Nb, and Fe. It contains elements, lithium, phosphorus, and oxygen. These compounds may be those in which some elements are partially replaced with other elements in order to improve their properties.
  • olivine-type lithium iron phosphorus oxide, lithium cobalt composite oxide, lithium nickel composite oxide, lithium manganese composite oxide, and lithium-manganese-nickel composite oxide are preferable.
  • these positive electrode active materials have a large capacity and a large energy density.
  • an aluminum foil can be used as the positive electrode current collector.
  • the positive electrode used in the lithium ion secondary battery of the present invention can be manufactured by a known manufacturing method.
  • any known lithium salt can be used and may be selected according to the type of active material.
  • CF 3 examples thereof include SO 3 Li, CH 3 SO 3 Li, LiCF 3 SO 3 , LiC 4 F 9 SO 3 , Li (CF 3 SO 2 ) 2 N, and lower fatty acid lithium carboxylate.
  • the solvent for dissolving the electrolyte is not particularly limited as long as it is usually used as a liquid component for dissolving the electrolyte, and ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), and dimethyl carbonate.
  • Carbonates such as (DMC), diethyl carbonate (DEC), methyl ethyl carbonate (MEC), vinylene carbonate (VC); lactones such as ⁇ -butyrolactone and ⁇ -valerolactone; trimethoxymethane, 1,2-dimethoxyethane , Diethyl ether, 2-ethoxyethane, tetrahydrofuran, 2-methyl tetrahydrofuran and other ethers; dimethylsulfoxide and other sulfoxides; 1,3-dioxolane, 4-methyl-1,3-dioxolane and other oxolanes; acetonitrile, nitromethane , Nitrogen-containing substances such as formamide and dimethylformamide; organic acid esters such as methyl formate, methyl acetate, ethyl acetate, butyl acetate, methyl propionate and ethyl propionate; phosphate triesters and jigli
  • Examples of the separator include a porous separator.
  • Examples of the form of the separator include a film, a film, and a non-woven fabric.
  • porous separator examples include polyolefin-based porous separators such as polypropylene and polyethylene; polyvinylidene fluoride, polyethylene oxide, polyacrylonitrile, polyvinylidene fluoride hexafluoropropylene copolymer and the like. Can be mentioned.
  • ND-1 An ND particle aqueous dispersion was prepared through the following steps.
  • (1) Generation step First, a molded explosive equipped with an electric detonator was placed inside a pressure-resistant container (made of iron, volume: 15 m 3 ) for detonation, and the container was sealed. As the explosive, 0.50 kg of a mixture of TNT and RDX (TNT / RDX (mass ratio) 50/50) was used. Next, the electric detonator was detonated and the explosive was detonated in the container. Next, the container and its inside were cooled by leaving it at room temperature for 24 hours. After this cooling, the ND particle crude product adhering to the inner wall of the container (including the ND particle coagulant and soot produced by the detonation method) was recovered to obtain the ND particle crude product. ..
  • the ND particle crude product obtained in the above step was subjected to acid treatment. Specifically, the slurry obtained by adding 6 L of 10% by mass hydrochloric acid to 200 g of the crude ND particle product is heat-treated for 1 hour under reflux under normal pressure conditions (heating temperature: 85 to 100 ° C.). ) was performed. Next, after cooling, the solid content (including the ND adherent and soot) was washed with water by decantation. The solid content was repeatedly washed with water by decantation until the pH of the precipitate was from the low pH side to 2.
  • the heating rate was 10 ° C./min up to 380 ° C., which is 20 ° C. lower than the set heating temperature, and 1 ° C./min from 380 ° C. to 400 ° C. thereafter.
  • the ND powder in the furnace was subjected to oxygen oxidation treatment.
  • the processing time was 3 hours.
  • the slurry that had undergone the crushing step was centrifuged using a centrifuge device (classification operation).
  • the centrifugal force in this centrifugation treatment was 20000 ⁇ g, and the centrifugation time was 10 minutes.
  • ND particle aqueous dispersion 25 mL of the supernatant of the ND particle-containing solution that had undergone the centrifugation treatment was recovered to obtain an ND particle aqueous dispersion (ND1).
  • the ND particle concentration in the ND particle aqueous dispersion was 11.8 g / L.
  • the pH was 9.33.
  • the particle size D50 was 3.97 nm
  • the particle size D90 was 7.20 nm
  • the zeta potential was ⁇ 42 mV.
  • Crystal structure analysis was performed on the particles in the obtained ND particle aqueous dispersion using an X-ray diffractometer (trade name "SmartLab", manufactured by Rigaku Co., Ltd.). As a result, a strong peak was observed at the analysis peak position of diamond, that is, the diffraction peak position from the (111) plane of the diamond crystal. From this, it was confirmed that the obtained particles were diamond particles.
  • Ultrapure water was added to the obtained aqueous dispersion of ND particles to adjust the solid content concentration of ND to 0.3 wt%, and electrodes were prepared.
  • Manufacturing example 2 (1) Modification Step The ND particle aqueous dispersion obtained in Production Example 1 was dried using an evaporator to obtain a black dry powder. Subsequently, a dispersion obtained by mixing 0.1 g of the obtained nanodiamond powder and 13.5 g of ethylene glycol was heated to 70 ° C. under a nitrogen atmosphere. 13.5 g of glycidol was added dropwise to this dispersion over 1 hour while maintaining 70 ° C., and after completion of the addition, the mixture was aged at the same temperature for 10 hours. After completion of aging, the mixture was cooled to room temperature, and the same amount of water as the reaction mixture was added to the reaction mixture to stop the reaction.
  • this reaction mixture was purified using a UF membrane (manufactured by Millipore, trade name “Amicon Bioseparations", manufactured by polyether sulfone, molecular weight cut off of 30,000). Permeation (solid-liquid separation using a membrane) -dilution [adding water to the remaining upper layer (valuable material)] was repeated, and purification was completed when the total dilution ratio reached 1 million times. In this way, a dispersion liquid (ND-2) of surface-modified nanodiamonds whose surface was modified with a group containing a polyglycerin chain was obtained.
  • ND-2 dispersion liquid
  • the particle size D 10 was 23 nm
  • D 50 (median diameter) was 40 nm
  • D 90 was. It was 78 nm.
  • the modification rate of the modifying group of the surface-modified nanodiamond in the surface-modified nanodiamond dispersion obtained above was measured and found to be 0.7.
  • Ultrapure water was added to the obtained aqueous dispersion of ND particles to adjust the solid content concentration of ND to 0.3 wt%, and electrodes were prepared.
  • Comparative manufacturing example 1 Ultrapure water was added to the ND powder (ND-3) obtained in the drying step of Production Example 1 to adjust the solid content concentration of ND to 0.3 wt%, and electrodes were manufactured. ..
  • FT-IR analysis conditions Fourier Transform Infrared Spectroscopy (FT-IR) was performed using an FT-IR apparatus (trade name "Spectrum 400 type FT-IR", manufactured by Perkin Elmer Japan Co., Ltd.). In this measurement, the infrared absorption spectrum was measured while heating the sample to 150 ° C. in a vacuum atmosphere. For heating in a vacuum atmosphere, a Model-HC900 type Heat Chamber manufactured by ST Japan and a TC-100WA type Thermo Controller were used in combination.
  • Solid content concentration of the surface-modified nanodiamond dispersion obtained as described above was measured as follows. That is, a Teflon (registered trademark) sheet is placed on a beaker, a few g of the dispersion liquid (sample) obtained above is placed on the beaker, treated in a 250 ° C. sand bath for several hours, and dried to some extent at 70 ° C. The solid content was vacuum-dried overnight, and the solid content concentration was determined from the weight of the remaining solid content.
  • the particle size distribution of the surface-modified nanodiamond was measured by a dynamic light scattering method. Specifically, the particle size distribution of surface-modified nanodiamonds was measured by a dynamic light scattering method (non-contact backscattering method) using an apparatus manufactured by Microtrac Bell (trade name "Nanotrac Wave II").
  • ⁇ Modification rate of modifying group> Regarding the surface-modified nanodiamond (solid obtained by drying the dispersion) in the surface-modified nanodiamond dispersion obtained as described above, TG / DTA (quartz pan, 30-800 ° C., heating rate 20 ° C./min) ) was used to determine the ratio of modifying groups to nanodiamond (ND) (modifying group weight / ND weight).
  • Examples 1 and 2 and Comparative Example 1 Composition of slurry for negative electrode
  • An electrode was prepared by mixing graphite, acetylene black, 50 wt% SBR, 1.5 wt% CMC aqueous solution, and 0.3 wt% ND aqueous dispersion at a ratio of 94.7 / 3/1/1 / 0.3 (solid content concentration 36.41 wt%). ..
  • the ND solid content was adjusted to be about 0.3 wt% with respect to graphite.
  • three types of electrodes were produced by using three different types of NDs (Table 1).
  • a copper foil with a thickness of about 20 ⁇ m was prepared as a current collector.
  • the slurry composition prepared above is applied to one side of a copper foil at a set value of 10 mil (254 ⁇ m) using a bar coder, and dried in an oven at about 60 ° C. for 30 minutes to form a lithium ion secondary battery.
  • a electrode for use was prepared.
  • the average dispersed particle size of ND dispersed in the electrodes was calculated by TEM observation.
  • the distance at which the longest straight line connecting the ends of the ND particles (existing as an agglomerate) was taken as the dispersed particle diameter, and the average value was calculated.

Abstract

The present invention provides a nanodiamond aqueous dispersion composition in which nanodiamond (ND) particles are dispersed in an aqueous medium containing a thickener, the ND particles having an average dispersed particle diameter of 5-100 nm.

Description

ナノダイヤモンド水性分散組成物、負極ペースト、負極及びリチウムイオン二次電池Nanodiamond aqueous dispersion composition, negative electrode paste, negative electrode and lithium ion secondary battery
　本発明は、ナノダイヤモンド水性分散組成物、負極ペースト、負極及びリチウムイオン二次電池に関する。 The present invention relates to a nanodiamond aqueous dispersion composition, a negative electrode paste, a negative electrode and a lithium ion secondary battery.
　本明細書において、ナノダイヤモンドを「ＮＤ」と記載することがある。 In this specification, nanodiamond may be referred to as "ND".
  リチウムイオン二次電池に用いられる負極は、一般的に、負極活物質層と集電体から主に構成されている。負極活物質層は、銅箔等の集電体表面に、負極活物質およびバインダーを含む負極ペーストを塗布して乾燥することにより得られる。 The negative electrode used in a lithium ion secondary battery is generally composed mainly of a negative electrode active material layer and a current collector. The negative electrode active material layer is obtained by applying a negative electrode paste containing a negative electrode active material and a binder to the surface of a current collector such as a copper foil and drying the negative electrode active material layer.
　非特許文献１は、尿素と酸を爆轟法ナノダイヤモンドと混合し、マイクロ波で熱処理し、アニールし、アルゴン雰囲気下に高温で炭素化し、さらにグラフェンナノシートを用いて負極を作製することを開示している。 Non-Patent Document 1 discloses that urea and acid are mixed with detonation nanodiamond, heat-treated with microwaves, annealed, carbonized at a high temperature under an argon atmosphere, and a negative electrode is prepared using graphene nanosheets. doing.
　特許文献１は、イオン注入法により導電性を持たせたナノダイヤモンドを使用したリチウムイオン電池を開示している。 Patent Document 1 discloses a lithium ion battery using nanodiamonds that have been made conductive by an ion implantation method.
CN 109888191 ACN 109888191 A
　本発明は、性能が向上したリチウムイオン二次電池用負極及び該負極を用いたリチウムイオン二次電池を提供することを目的とする。 An object of the present invention is to provide a negative electrode for a lithium ion secondary battery having improved performance and a lithium ion secondary battery using the negative electrode.
　本発明は、以下のナノダイヤモンド水性分散組成物、負極ペースト、負極及びリチウムイオン二次電池を提供するものである。
〔１〕　　ナノダイヤモンド（ＮＤ）粒子が増粘剤を含む水性溶媒に分散した、ナノダイヤモンド水性分散組成物であって、前記ＮＤ粒子の平均分散粒子径が５～１００ｎｍである、ナノダイヤモンド水性分散組成物。
〔２〕　　ナノダイヤモンドの一次粒子は球状、楕円体状或いは多面体状である、〔１〕に記載のナノダイヤモンド水性分散組成物。
〔３〕　　増粘剤がカルボキシメチルセルロースナトリウム（ＣＭＣ）である、〔１〕又は〔２〕に記載のナノダイヤモンド水性分散組成物。
〔４〕　　ＮＤ一次粒子の平均粒子径が１０ｎｍ以下である、〔１〕～〔３〕のいずれか１項に記載のナノダイヤモンド水性分散組成物。
〔５〕　　〔１〕～〔４〕のいずれか１項に記載のナノダイヤモンド水性分散組成物と負極活物質及びバインダーを含むことを特徴とするリチウムイオン二次電池用負極ペースト。
〔６〕　　〔５〕に記載の負極ペーストを用いて作製されることを特徴とするリチウムイオン二次電池用負極。
〔７〕　　リチウムイオン二次電池用負極中におけるＮＤ粒子の平均分散粒子径が５～１００ｎｍである、〔６〕記載のリチウムイオン二次電池用負極。
〔８〕　　〔６〕に記載の負極と正極と電解質を備えたリチウムイオン二次電池。 The present invention provides the following nanodiamond aqueous dispersion composition, negative electrode paste, negative electrode and lithium ion secondary battery.
[1] Nanodiamond aqueous dispersion in which nanodiamond (ND) particles are dispersed in an aqueous solvent containing a thickener, wherein the average dispersed particle size of the ND particles is 5 to 100 nm. Composition.
[2] The nanodiamond aqueous dispersion composition according to [1], wherein the primary particles of nanodiamond are spherical, ellipsoidal or polyhedral.
[3] The nanodiamond aqueous dispersion composition according to [1] or [2], wherein the thickener is sodium carboxymethyl cellulose (CMC).
[4] The nanodiamond aqueous dispersion composition according to any one of [1] to [3], wherein the average particle size of the ND primary particles is 10 nm or less.
[5] A negative electrode paste for a lithium ion secondary battery, which comprises the nanodiamond aqueous dispersion composition according to any one of [1] to [4], a negative electrode active material, and a binder.
[6] A negative electrode for a lithium ion secondary battery, which is produced by using the negative electrode paste according to [5].
[7] The negative electrode for a lithium ion secondary battery according to [6], wherein the average dispersed particle size of the ND particles in the negative electrode for a lithium ion secondary battery is 5 to 100 nm.
[8] A lithium ion secondary battery comprising the negative electrode, the positive electrode, and the electrolyte according to [6].
　本発明によれば、負極中にＮＤが高分散しているので、ＮＤの少量添加で電池容量、サイクル特性などの性能が向上したリチウムイオン二次電池を提供することができる。 According to the present invention, since ND is highly dispersed in the negative electrode, it is possible to provide a lithium ion secondary battery in which performance such as battery capacity and cycle characteristics is improved by adding a small amount of ND.
実施例１で得られたグラファイト電極に関して、電極中に分散しているNDの平均分散粒子径をＴＥＭ観察により測定したときの顕微鏡写真。ND粒子の平均分散粒子径は34.47 nmと小さく、良好な分散性が確認された。A micrograph of the graphite electrode obtained in Example 1 when the average dispersed particle size of ND dispersed in the electrode was measured by TEM observation. The average dispersed particle size of the ND particles was as small as 34.47 nm, and good dispersibility was confirmed. 実施例２で得られたグラファイト電極に関して、電極中に分散しているNDの平均分散粒子径をＴＥＭ観察により測定したときの顕微鏡写真。ND粒子の平均分散粒子径は34.48 nmと小さく、良好な分散性が確認された。A micrograph of the graphite electrode obtained in Example 2 when the average dispersed particle size of ND dispersed in the electrode was measured by TEM observation. The average dispersed particle size of the ND particles was as small as 34.48 nm, and good dispersibility was confirmed. 比較例１で得られたグラファイト電極に関して、電極中に分散しているNDの平均分散粒子径をＴＥＭ観察により測定したときの顕微鏡写真。修飾していないNDを用いた電極の場合、ND粒子の平均分散粒子径は210.40 nmであり、ND粒子の一定の分散性は窺えるものの、局所的な凝集体も確認され分散性は悪いことが疑われた。A micrograph of the graphite electrode obtained in Comparative Example 1 when the average dispersed particle size of ND dispersed in the electrode was measured by TEM observation. In the case of an electrode using unmodified ND, the average dispersed particle size of ND particles is 210.40 nm, and although a certain dispersibility of ND particles can be seen, local agglomerates are also confirmed and the dispersibility is poor. I was suspected.
＜ナノダイヤモンド水性分散組成物＞
　本発明の第１の実施形態では、ＮＤ水性分散組成物を提供する。該組成物は、ＮＤ粒子、増粘剤及び水性溶媒を含む。ＮＤ水性分散組成物に含まれるＮＤ粒子はＮＤ一次粒子が含まれていてもよいが、複数のＮＤ一次粒子が凝集した凝集体として存在する。 <Nanodiamond aqueous dispersion composition>
In the first embodiment of the present invention, an ND aqueous dispersion composition is provided. The composition contains ND particles, a thickener and an aqueous solvent. The ND particles contained in the ND aqueous dispersion composition may contain ND primary particles, but exist as agglomerates in which a plurality of ND primary particles are aggregated.
　増粘剤は、ＮＤ水性分散組成物を用いて得られる負極ペーストの集電体への塗工性を向上させるものであれば特に限定されない。増粘剤としては、例えば、カルボキシメチルセルロース、メチルセルロース、ヒドロキシプロピルセルロース等のセルロース系ポリマー、これらのセルロース系ポリマーのアンモニウム塩もしくはアルカリ金属塩、ポリカルボン酸又はその塩、ポリエチレンオキシド、ポリビニルピロリドン、ポリビニルアルコール、ポリ（メタ）アクリル酸アルカリ金属塩（例えばナトリウム塩）等のポリ（メタ）アクリル酸塩等の水溶性ポリマーが挙げられる。 The thickener is not particularly limited as long as it improves the coatability of the negative electrode paste obtained by using the ND aqueous dispersion composition on the current collector. Examples of the thickener include cellulose-based polymers such as carboxymethyl cellulose, methyl cellulose, and hydroxypropyl cellulose, ammonium salts or alkali metal salts of these cellulose-based polymers, polycarboxylic acids or salts thereof, polyethylene oxide, polyvinylpyrrolidone, and polyvinyl alcohol. , Poly (meth) acrylic acid alkali metal salt (for example, sodium salt) and other water-soluble polymers such as poly (meth) acrylate.
　これらの中でもセルロース系ポリマー、セルロース系ポリマーのアンモニウム塩、セルロース系ポリマーのアルカリ金属塩が好ましく、カルボキシメチルセルロース、カルボキシメチルセルロースのアンモニウム塩、カルボキシメチルセルロースのアルカリ金属塩（ナトリウム塩、カリウム塩、リチウム塩）がより好ましく、カルボキシメチルセルロースのナトリウム塩（ＣＭＣ）が特に好ましい。 Among these, cellulose-based polymers, ammonium salts of cellulose-based polymers, and alkali metal salts of cellulose-based polymers are preferable, and carboxymethyl cellulose, ammonium salts of carboxymethyl cellulose, and alkali metal salts of carboxymethyl cellulose (sodium salt, potassium salt, lithium salt) are preferable. More preferably, the sodium salt of carboxymethyl cellulose (CMC) is particularly preferred.
　水性溶媒は、ＮＤ粒子が分散できるものであれば特に限定されないが、蒸留水、イオン交換水、市水、工業用水が好ましく、水と水混和性溶媒（メタノール、エタノール、プロパノール、アセトン、ＴＨＦ、ＤＭＦ、ＤＭＳＯ、アセトニトリルなど）を含む含水溶媒であってもよい。 The aqueous solvent is not particularly limited as long as the ND particles can be dispersed, but distilled water, ion-exchanged water, city water, and industrial water are preferable, and water-water miscible solvents (methanol, ethanol, propanol, acetone, THF, etc. It may be a water-containing solvent containing DMF, DMSO, acetonitrile, etc.).
　ＮＤは、一次粒子が好ましくは球状、楕円体状或いはそれらに近い多面体状、より好ましくは球状のものである。ＮＤは、爆轟法により製造されたＮＤが好ましい。 The primary particles of ND are preferably spherical, ellipsoidal or polyhedral, and more preferably spherical. The ND is preferably an ND produced by the detonation method.
　ＮＤ一次粒子の平均粒子径は、好ましくは１～１０ｎｍ程度、より好ましくは４～６ｎｍ程度である。なお、ＮＤ一次粒子の平均粒子径は、Ｘ線回析装置（商品名「Ｓｍａｒｔ Ｌａｂ」，リガク社製）を使用して小角Ｘ線散乱測定（ＳＡＸＳ法）を行い、粒子径分布解析ソフト（商品名「ＮＡＮＯ－Ｓｏｌｖｅｒ」，リガク社製）を使用して、散乱角度１° ～３°の領域についてナノダイヤモンドの一次粒子径を見積もることにより決定できる。また、ＮＤ一次粒子の平均粒子径は、粉末Ｘ線回折法(XRD) の分析結果から、シェラーの式により求めることができる。XRDの測定装置は、例えば、全自動多目的X線回折装置（株式会社リガク製）を挙げることができる。 The average particle size of the ND primary particles is preferably about 1 to 10 nm, more preferably about 4 to 6 nm. The average particle size of the ND primary particles is measured by small-angle X-ray scattering measurement (SAXS method) using an X-ray diffractometer (trade name "SmartLab", manufactured by Rigaku Co., Ltd.), and particle size distribution analysis software (Sanx method). It can be determined by estimating the primary particle size of nanodiamonds in the region of scattering angle 1 ° to 3 ° using the trade name "NANO-Solver" (manufactured by Rigaku Co., Ltd.). Further, the average particle size of the ND primary particles can be obtained by Scherrer's formula from the analysis result of the powder X-ray diffraction method (XRD). Examples of the XRD measuring device include a fully automatic multipurpose X-ray diffractometer (manufactured by Rigaku Co., Ltd.).
　本発明の好ましい１つの実施形態において、ＮＤ水性分散組成物に含まれるＮＤ粒子のゼータ電位は、好ましくは－２０～－８０ｍＶ、より好ましくは－４０～－６０ｍＶである。ＮＤ水性分散組成物に含まれるＮＤ粒子のゼータ電位は、Ｍａｌｖｅｒｎ社製の装置（商品名「ゼータサイザー　ナノＺＳ」）を使用して、レーザードップラー式電気泳動法によって測定することができる。測定に付されるＮＤ水性分散組成物は、ＮＤ粒子濃度が０.２質量％となるように超純水で希釈された後に超音波洗浄機による超音波照射を経たものであり、ゼータ電位測定温度は２５℃である。 In one preferred embodiment of the present invention, the zeta potential of the ND particles contained in the ND aqueous dispersion composition is preferably −20 to −80 mV, more preferably −40 to −60 mV. The zeta potential of the ND particles contained in the ND aqueous dispersion composition can be measured by a laser Doppler electrophoresis method using an apparatus manufactured by Malvern (trade name "Zetasizer Nano ZS"). The ND aqueous dispersion composition to be measured is diluted with ultrapure water so that the ND particle concentration becomes 0.2% by mass, and then subjected to ultrasonic irradiation with an ultrasonic cleaner, and zeta potential measurement is performed. The temperature is 25 ° C.
　ＮＤ一次粒子は酸素酸化処理又は親水性高分子で表面修飾されたものが好ましい。 The ND primary particles are preferably those that have been surface-modified with oxygen oxidation treatment or a hydrophilic polymer.
　なお、爆轟法で得られるナノダイヤモンドは一次粒子の凝集体として得られるが、この凝集体には一次粒子が含まれているので、ＮＤ一次粒子とＮＤ凝集体を含む概念として、以下において「ＮＤ粉体」と記載することがある。 The nanodiamond obtained by the detonation method is obtained as an aggregate of primary particles, but since this aggregate contains primary particles, the concept of including ND primary particles and ND aggregates is described below. It may be described as "ND powder".
　酸素酸化処理は、ガス雰囲気炉を使用してＮＤ粉体を酸素を含有する所定組成のガス雰囲気下にて加熱することで実施できる。具体的には、ガス雰囲気炉内にＮＤ粉体が配され、当該炉に対して酸素含有ガスが供給ないし通流され、加熱温度として設定された温度条件まで当該炉内が昇温されて酸素酸化処理が実施される。 The oxygen oxidation treatment can be carried out by heating the ND powder in a gas atmosphere having a predetermined composition containing oxygen using a gas atmosphere furnace. Specifically, ND powder is arranged in a gas atmosphere furnace, oxygen-containing gas is supplied or passed through the furnace, and the temperature inside the furnace is raised to the temperature condition set as the heating temperature to obtain oxygen. Oxidation treatment is carried out.
　酸素酸化処理は、本発明のＮＤ水性分散組成物中のＮＤ粒子の分散粒子径が所定の範囲になるような条件で行うことができる。 The oxygen oxidation treatment can be carried out under conditions such that the dispersed particle size of the ND particles in the ND aqueous dispersion composition of the present invention is within a predetermined range.
　酸素酸化処理の温度条件は、例えば２５０～５００℃である。ネガティブのゼータ電位を有する親水性ＮＤ粒子を得るためには、この酸素酸化処理の温度条件は、比較的に高温であることが好ましく、例えば４００～４５０℃である。また、前記酸素含有ガスは、酸素に加えて不活性ガスを含有する混合ガスである。不活性ガスとしては、例えば、窒素、アルゴン、二酸化炭素、およびヘリウムが挙げられる。当該混合ガスの酸素濃度は、例えば１～３５体積％である。 The temperature condition of the oxygen oxidation treatment is, for example, 250 to 500 ° C. In order to obtain hydrophilic ND particles having a negative zeta potential, the temperature condition of this oxygen oxidation treatment is preferably relatively high temperature, for example, 400 to 450 ° C. The oxygen-containing gas is a mixed gas containing an inert gas in addition to oxygen. Examples of the inert gas include nitrogen, argon, carbon dioxide, and helium. The oxygen concentration of the mixed gas is, for example, 1 to 35% by volume.
　表面修飾に使用される親水性高分子としては、ポリグリセリン、ポリビニルピロリドン、ポリエチレングリコール、ポリビニルアルコール、ポリ（メタ）アクリル酸、ポリアクリルアミド、ポリエチレンイミン、ビニルエーテル系重合体、セルロース誘導体、水溶性ポリエステル、天然高分子多糖類などが挙げられる。ビニルエーテル系重合体としては、ビニルメチルエーテル、ビニルエチルエーテル、ビニルイソプロピルエーテル、ビニルブチルエーテル、ビニルイソブチルエーテルなどのアルキルビニルエーテル類などの単独又は共重合体（例えば、ポリビニルメチルエーテル、ポリビニルエチルエーテル、ビニルエーテル－無水マレイン酸共重合体など）が挙げられる。セルロース誘導体としては、メチルセルロース、エチルセルロース、プロピルセルロース、ヒドロキシエチルセルロース、ヒドロキシプロピルセルロース、ヒドロキシエチルメチルセルロース、ヒドロキシプロピルメチルセルロース、カルボキシメチルセルロース、カルボキシエチルセルロースなどが挙げられる。水溶性ポリエステルとしては、ポリジメチロールプロピオン酸エステルなどが挙げられる。天然高分子多糖類としては、アルギン酸又はその塩、ペクチン、デンプン、寒天、アラビアゴム、デキストリン、カラギーナンなどが挙げられる。好ましい親水性高分子は、ポリグリセリン、ポリビニルピロリドン、ポリエチレングリコール、ポリビニルアルコール、ポリ（メタ）アクリル酸であり、ポリグリセリンが特に好ましい。 Hydrophilic polymers used for surface modification include polyglycerin, polyvinylpyrrolidone, polyethylene glycol, polyvinyl alcohol, poly (meth) acrylic acid, polyacrylamide, polyethyleneimine, vinyl ether-based polymers, cellulose derivatives, and water-soluble polyesters. Examples include natural high molecular weight polysaccharides. Examples of the vinyl ether-based polymer include simple or copolymers such as alkyl vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, vinyl isopropyl ether, vinyl butyl ether, and vinyl isobutyl ether (for example, polyvinyl methyl ether, polyvinyl ethyl ether, and vinyl ether-. (Maleic anhydride copolymer, etc.) can be mentioned. Examples of the cellulose derivative include methyl cellulose, ethyl cellulose, propyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxyethyl methyl cellulose, hydroxypropyl methyl cellulose, carboxymethyl cellulose, carboxyethyl cellulose and the like. Examples of the water-soluble polyester include polydimethylolpropionic acid ester. Examples of the natural high molecular weight polysaccharide include alginic acid or a salt thereof, pectin, starch, agar, gum arabic, dextrin, carrageenan and the like. Preferred hydrophilic polymers are polyglycerin, polyvinylpyrrolidone, polyethylene glycol, polyvinyl alcohol and poly (meth) acrylic acid, with polyglycerin being particularly preferred.
　親水性高分子で修飾されたＮＤ粒子は、ＮＤ粒子の表面基（ＯＨ、ＮＨ２、ＣＯＯＨなど）と親水性高分子が共有結合により結合することが好ましい。ＮＤ粒子の親水性高分子による修飾は、酸などの触媒を使用する方法、加熱して脱水縮合させる方法、脱水縮合剤を用いる方法などの常法に従い行うことができる。 In the ND particles modified with the hydrophilic polymer, it is preferable that the surface groups (OH, NH 2 , COOH, etc.) of the ND particles and the hydrophilic polymer are covalently bonded to each other. Modification of the ND particles with a hydrophilic polymer can be carried out according to a conventional method such as a method using a catalyst such as an acid, a method of heating and dehydrating and condensing, and a method of using a dehydration condensing agent.
　本発明の分散液におけるＮＤ粒子の平均分散粒子径は、好ましくは５～１００ｎｍ程度、より好ましくは５～５０ｎｍ程度である。ＮＤ粒子の平均分散粒子径が１００ｎｍを超えると、ＮＤの添加効果が低くなるので好ましくない。なお、平均分散粒子径は、透過電子顕微鏡法（ＴＥＭ）により測定してもよく、動的光散乱法（ＤＬＳ）により測定してもよい。 The average dispersed particle size of the ND particles in the dispersion liquid of the present invention is preferably about 5 to 100 nm, more preferably about 5 to 50 nm. If the average dispersed particle size of the ND particles exceeds 100 nm, the effect of adding ND becomes low, which is not preferable. The average dispersed particle size may be measured by a transmission electron microscope (TEM) or a dynamic light scattering method (DLS).
　ナノダイヤモンド水性分散組成物におけるＮＤ粒子の濃度は、好ましくは０．１～１．０質量％程度、より好ましくは０．１～０．５質量％程度である。 The concentration of ND particles in the nanodiamond aqueous dispersion composition is preferably about 0.1 to 1.0% by mass, more preferably about 0.1 to 0.5% by mass.
　ナノダイヤモンド水性分散組成物における増粘剤の濃度は、好ましくは０．１～５．０質量％程度、より好ましくは０．１～３．０質量％程度である。 The concentration of the thickener in the nanodiamond aqueous dispersion composition is preferably about 0.1 to 5.0% by mass, more preferably about 0.1 to 3.0% by mass.
　ナノダイヤモンド水性分散組成物におけるＮＤ粒子と増粘剤の質量比（ＮＤ粒子の質量／増粘剤の質量）は、好ましくは０．１～１．０程度、より好ましくは０．１～０．５程度である。 The mass ratio of the ND particles to the thickener (mass of the ND particles / mass of the thickener) in the nanodiamond aqueous dispersion composition is preferably about 0.1 to 1.0, more preferably 0.1 to 0. It is about 5.
＜リチウムイオン二次電池用負極ペースト＞
　本発明の他の１つの実施形態は、上記のND水性分散組成物と負極活物質とバインダーを含むリチウムイオン二次電池用負極ペーストである。 <Negative electrode paste for lithium ion secondary batteries>
Another embodiment of the present invention is a negative electrode paste for a lithium ion secondary battery containing the above-mentioned ND aqueous dispersion composition, a negative electrode active material, and a binder.
　負極活物質としては、リチウムイオン二次電池の負極に使用可能な通常の負極活物質であれば特に限定されない。例えば、天然黒鉛、人造黒鉛、樹脂炭、炭素繊維、活性炭、ハードカーボン、ソフトカーボン等の炭素材料；リチウム金属、リチウム合金等のリチウム系金属；シリコン、スズ等の金属；ポリアセン、ポリアセチレン、ポリピロール等の導電性ポリマー等が挙げられる。これらの中でも炭素材料が好ましく、特に天然黒鉛や人造黒鉛等の黒鉛質材料が好ましい。 The negative electrode active material is not particularly limited as long as it is a normal negative electrode active material that can be used for the negative electrode of a lithium ion secondary battery. For example, carbon materials such as natural graphite, artificial graphite, resin charcoal, carbon fiber, activated charcoal, hard carbon, and soft carbon; lithium-based metals such as lithium metal and lithium alloy; metals such as silicon and tin; polyacene, polyacetylene, polypyrrole, etc. Examples include the conductive polymer of. Among these, a carbon material is preferable, and a graphite material such as natural graphite or artificial graphite is particularly preferable.
  黒鉛質材料としては、リチウムイオン二次電池の負極に使用可能な通常の黒鉛質材料であれば特に限定されない。例えば、天然黒鉛、石油系および石炭系コークスを熱処理することで製造される人造黒鉛等が挙げられる。 The graphitic material is not particularly limited as long as it is an ordinary graphitic material that can be used for the negative electrode of a lithium ion secondary battery. Examples thereof include artificial graphite produced by heat-treating natural graphite, petroleum-based and coal-based coke.
  ここで、天然黒鉛とは、鉱石として天然に産出する黒鉛のことをいう。本実施形態の核材として用いる天然黒鉛は、産地や性状、種類は特に限定されない。 Here, natural graphite refers to graphite naturally produced as an ore. The production area, properties, and type of natural graphite used as the core material of the present embodiment are not particularly limited.
  人造黒鉛とは、人工的な手法で作られた黒鉛および黒鉛の完全結晶に近い黒鉛をいう。このような人造黒鉛は、例えば、石炭の乾留、原油の蒸留による残渣等から得られるタールやコークスを原料にして、焼成工程、黒鉛化工程を経ることにより得られる。 Artificial graphite refers to graphite made by an artificial method and graphite that is close to a perfect crystal of graphite. Such artificial graphite can be obtained, for example, by using tar or coke obtained from dry distillation of coal, residue obtained by distillation of crude oil, or the like as a raw material, and undergoing a firing step and a graphitization step.
  黒鉛質材料は、黒鉛粉末を核材とし、上記黒鉛粉末の表面の少なくとも一部が上記黒鉛粉末よりも結晶性の低い炭素材料により被覆されているもの（以下、表面被覆黒鉛とも呼ぶ。）が好ましい。特に黒鉛粉末のエッジ部が上記炭素材料により被覆されていることが好ましい。黒鉛粉末のエッジ部が被覆されることにより、エッジ部と電解液との不可逆的な反応を抑制することができ、その結果、不可逆容量の増大による初期の充放電効率の低下を抑制することができる。 The graphite material has graphite powder as a core material, and at least a part of the surface of the graphite powder is coated with a carbon material having a lower crystallinity than the graphite powder (hereinafter, also referred to as surface-coated graphite). preferable. In particular, it is preferable that the edge portion of the graphite powder is coated with the above carbon material. By coating the edge portion of the graphite powder, the irreversible reaction between the edge portion and the electrolytic solution can be suppressed, and as a result, the decrease in the initial charge / discharge efficiency due to the increase in the irreversible capacity can be suppressed. can.
  表面被覆黒鉛を用いると、黒鉛単独のときよりもバインダーとの結着性を向上させることができるため、結着剤の量を減らすことができる。その結果、得られるリチウムイオン二次電池の電池特性を向上させることができる。 When surface-coated graphite is used, the binding property with the binder can be improved as compared with the case of graphite alone, so that the amount of the binder can be reduced. As a result, the battery characteristics of the obtained lithium ion secondary battery can be improved.
  ここで、上記黒鉛粉末よりも結晶性の低い炭素材料とは、例えば、ソフトカーボン、ハードカーボン等のアモルファスカーボンである。 Here, the carbon material having a lower crystallinity than the graphite powder is, for example, amorphous carbon such as soft carbon and hard carbon.
  核材として用いる黒鉛粉末としては、例えば、天然黒鉛、石油系および石炭系コークスを熱処理することで製造される人造黒鉛等が挙げられる。本実施形態においては、これらの黒鉛粉末を一種単独で用いてもよく、二種以上を組み合わせて用いてもよい。これらの中でも、コストの点から、天然黒鉛が好ましい。 Examples of graphite powder used as a core material include natural graphite, artificial graphite produced by heat-treating petroleum-based and coal-based coke. In the present embodiment, these graphite powders may be used alone or in combination of two or more. Among these, natural graphite is preferable from the viewpoint of cost.
  本実施形態に係る表面被覆黒鉛は、焼成工程により炭素化されて上記黒鉛粉末よりも結晶性の低い炭素材料となる有機化合物と、黒鉛粉末とを混合した後に、上記有機化合物を焼成炭素化することによって作製することができる。 The surface-coated graphite according to the present embodiment is obtained by mixing an organic compound which is carbonized by a firing step to become a carbon material having a lower crystallinity than the graphite powder and the graphite powder, and then the organic compound is calcined and carbonized. It can be produced by.
　黒鉛粉末と混合する有機化合物は、焼成することによって炭素化して、黒鉛粉末よりも結晶性の低い炭素材料が得られるものであれば特に限定されないが、例えば、石油系タール、石炭系タール等のタール；石油系ピッチ、石炭系ピッチ等のピッチ；ポリ塩化ビニル、ポリビニルアセテート、ポリビニルブチラール、ポリビニルアルコール、ポリ塩化ビニリデン、ポリアクリロニトリル等の熱可塑性樹脂；フェノール樹脂、フルフリルアルコール樹脂等の熱硬化性樹脂；セルロース等の天然樹脂；ナフタレン、アルキルナフタレン、アントラセン等の芳香族炭化水素等が挙げられる。 The organic compound to be mixed with the graphite powder is not particularly limited as long as it can be carbonized by firing to obtain a carbon material having a lower crystallinity than the graphite powder. Tar; Pitch of petroleum-based pitch, pitch of coal-based pitch, etc .; Thermoplastic resin such as polyvinyl chloride, polyvinyl acetate, polyvinyl butyral, polyvinyl alcohol, polyvinylidene chloride, polyacrylonitrile; Thermosetting resin such as phenol resin, furfuryl alcohol resin, etc. Resins; natural resins such as cellulose; aromatic hydrocarbons such as naphthalene, alkylnaphthalene, and anthracene can be mentioned.
  本実施形態においては、これらの有機化合物は一種単独で用いてもよく、二種以上を組み合わせて用いてもよい。また、これらの有機化合物は、必要に応じて、溶媒により溶解または分散させて用いてもよい。 In the present embodiment, these organic compounds may be used alone or in combination of two or more. Moreover, these organic compounds may be used by being dissolved or dispersed with a solvent, if necessary.
  上記有機化合物の中でも、価格の点からタールおよびピッチが好ましい。 Among the above organic compounds, tar and pitch are preferable from the viewpoint of price.
  負極活物質のレーザー回折散乱式粒度分布測定法による体積基準粒度分布における平均粒子径は特に限定されないが、５～１００μｍであることが好ましく、５～５０μｍであることがより好ましい。負極活物質の平均粒子径は、例えば動的光散乱法（ＤＬＳ）、レーザー回折散乱式粒度分布測定法などにより測定することができる。 The average particle size in the volume-based particle size distribution measured by the laser diffraction / scattering particle size distribution measurement method for the negative electrode active material is not particularly limited, but is preferably 5 to 100 μm, more preferably 5 to 50 μm. The average particle size of the negative electrode active material can be measured by, for example, a dynamic light scattering method (DLS), a laser diffraction scattering type particle size distribution measurement method, or the like.
  負極活物質の使用量としては、負極ペーストの固形分に対し、好ましくは６０～９０質量％、より好ましくは８０～９０質量％である。 The amount of the negative electrode active material used is preferably 60 to 90% by mass, more preferably 80 to 90% by mass, based on the solid content of the negative electrode paste.
　本発明の負極ペーストに含まれるバインダーは、電極成形が可能であり、十分な電気化学的安定性を有していれば特に限定されないが、例えば、ポリアクリル酸、ポリテトラフルオロエチレン、ポリフッ化ビニリデン、スチレンブタジエンゴム（ＳＢＲ）、ポリイミド等が挙げられる。バインダーは一種単独で用いてもよく、二種以上を組み合わせて用いてもよい。これらの中でも、スチレンブタジエンゴムが好ましい。 The binder contained in the negative electrode paste of the present invention is not particularly limited as long as it can form an electrode and has sufficient electrochemical stability, and is not particularly limited, but for example, polyacrylic acid, polytetrafluoroethylene, and polyvinylidene fluoride. , Styrene-butadiene rubber (SBR), polyimide and the like. The binder may be used alone or in combination of two or more. Among these, styrene-butadiene rubber is preferable.
  バインダーの使用量としては、負極ペーストの固形分に対し、好ましくは０．５～３．０質量％、より好ましくは０．５～１．０質量％である。 The amount of the binder used is preferably 0.5 to 3.0% by mass, more preferably 0.5 to 1.0% by mass, based on the solid content of the negative electrode paste.
　本発明の負極ペーストは水性溶媒を含む。水性溶媒としては、ＮＤ水性分散組成物で例示したものを使用することができる。 The negative electrode paste of the present invention contains an aqueous solvent. As the aqueous solvent, those exemplified in the ND aqueous dispersion composition can be used.
　水性溶媒の使用量は、負極ペーストの全量に対し、好ましくは３０～７０質量％、より好ましくは４０～６０質量％である。 The amount of the aqueous solvent used is preferably 30 to 70% by mass, more preferably 40 to 60% by mass, based on the total amount of the negative electrode paste.
  本発明のリチウムイオン二次電池用負極ペーストには導電助剤をさらに添加してもよい。 A conductive auxiliary agent may be further added to the negative electrode paste for a lithium ion secondary battery of the present invention.
  導電助剤は、電子伝導性を有しており、電極の導電性を向上させるものであれば特に限定されないが、例えば、アセチレンブラック、ケッチェンブラック、カーボンブラック、カーボンナノファイバーなどが挙げられる。これらの導電助剤は１種単独で使用してもよいし、２種以上を組み合わせて使用してもよい。 The conductive auxiliary agent is not particularly limited as long as it has electron conductivity and improves the conductivity of the electrode, and examples thereof include acetylene black, ketjen black, carbon black, and carbon nanofibers. These conductive auxiliaries may be used alone or in combination of two or more.
  導電助剤の使用量としては、負極ペーストの固形分に対し、好ましくは１．０～１５質量％、より好ましくは１．０～５．０質量％である。 The amount of the conductive auxiliary agent used is preferably 1.0 to 15% by mass, more preferably 1.0 to 5.0% by mass, based on the solid content of the negative electrode paste.
＜リチウムイオン二次電池用負極＞
　本発明の負極は、本発明の負極ペーストを集電体上に塗布して乾燥することにより得ることができる。 <Negative electrode for lithium ion secondary battery>
The negative electrode of the present invention can be obtained by applying the negative electrode paste of the present invention on a current collector and drying it.
  負極ペーストを集電体上に塗布する方法は、公知の方法を用いることができ、例えば、リバースロール法、ダイレクトロール法、ドクターブレード法、ナイフ法、エクストルージョン法、カーテン法、グラビア法、バー法、ディップ法およびスクイーズ法等が挙げられる。 As a method of applying the negative electrode paste on the current collector, a known method can be used, for example, a reverse roll method, a direct roll method, a doctor blade method, a knife method, an extrusion method, a curtain method, a gravure method, and a bar. Examples include the method, the dip method and the squeeze method.
  負極ペーストは、集電体の片面のみに塗布しても両面に塗布してもよい。集電体の両面に塗布する場合は、片面ずつ逐次でも、両面同時に塗布してもよい。塗布層の厚さ、長さや幅は、電池の大きさに応じて、適宜決定することができる。 The negative electrode paste may be applied to only one side of the current collector or to both sides. When it is applied to both sides of the current collector, it may be applied sequentially on one side or at the same time on both sides. The thickness, length and width of the coating layer can be appropriately determined according to the size of the battery.
  塗布した負極ペーストの乾燥方法は、一般的に公知の方法を用いることができる。特に、熱風、真空、赤外線、遠赤外線、電子線および低温風を単独あるいは組み合わせて用いることが好ましい。乾燥温度は特に限定されないが、例えば６０～８０℃である。 As a method for drying the applied negative electrode paste, a generally known method can be used. In particular, it is preferable to use hot air, vacuum, infrared rays, far infrared rays, electron beams and low temperature air alone or in combination. The drying temperature is not particularly limited, but is, for example, 60 to 80 ° C.
  負極の製造に用いられる集電体としては、リチウムイオン二次電池に使用可能な通常の集電体であれば特に限定されないが、価格や入手容易性、電気化学的安定性等の観点から、銅が好ましい。また、集電体の形状についても特に限定されないが、例えば、厚さが１５～２０μｍの箔状のものを用いることができる。 The current collector used for manufacturing the negative electrode is not particularly limited as long as it is a normal current collector that can be used for a lithium ion secondary battery, but from the viewpoint of price, availability, electrochemical stability, etc. Copper is preferred. The shape of the current collector is also not particularly limited, but for example, a foil-like current collector having a thickness of 15 to 20 μm can be used.
  本実施形態に係るリチウムイオン二次電池用負極は、必要に応じてプレスしてもよい。プレスの方法としては、一般的に公知の方法を用いることができる。例えば、金型プレス法やカレンダープレス法等が挙げられる。 The negative electrode for the lithium ion secondary battery according to the present embodiment may be pressed if necessary. As a pressing method, a generally known method can be used. For example, a die pressing method, a calendar pressing method, and the like can be mentioned.
＜リチウムイオン二次電池＞
  本発明のリチウムイオン二次電池は、上記のリチウムイオン二次電池用負極と、電解質と、正極を備え、さらにセパレータを備えていることが好ましい。 <Lithium-ion secondary battery>
The lithium ion secondary battery of the present invention preferably includes the above-mentioned negative electrode for a lithium ion secondary battery, an electrolyte, a positive electrode, and further includes a separator.
  本実施形態に係るリチウムイオン二次電池は公知の方法に準じて作製することができる。 The lithium ion secondary battery according to this embodiment can be manufactured according to a known method.
  電極は、例えば、積層体や捲回体が使用できる。外装体としては、金属外装体やアルミラミネート外装体が適宜使用できる。電池の形状は、コイン型、ボタン型、シート型、円筒型、角型、扁平型等いずれの形状であってもよい。 As the electrode, for example, a laminated body or a wound body can be used. As the exterior body, a metal exterior body or an aluminum laminated exterior body can be appropriately used. The shape of the battery may be any of coin type, button type, sheet type, cylindrical type, square type, flat type and the like.
  本発明のリチウムイオン二次電池の正極に使用する正極活物質は用途に応じて適宜選択されるが、リチウムイオンを可逆に放出・吸蔵でき、電子輸送が容易に行えるように電子伝導度が高い材料が好ましい。例えば、リチウムニッケル複合酸化物、リチウムコバルト複合酸化物、リチウムマンガン複合酸化物、リチウム－マンガン－ニッケル複合酸化物等のリチウムと遷移金属との複合酸化物；ＴｉＳ２、ＦｅＳ、ＭｏＳ２等の遷移金属硫化物；ＭｎＯ、Ｖ２Ｏ５、Ｖ６Ｏ１３、ＴｉＯ２等の遷移金属酸化物、オリビン型リチウムリン酸化物等が挙げられる。 The positive electrode active material used for the positive electrode of the lithium ion secondary battery of the present invention is appropriately selected according to the application, but the lithium ions can be reversibly released and occluded, and the electron conductivity is high so that electron transport can be easily performed. The material is preferred. For example, composite oxides of lithium and transition metals such as lithium nickel composite oxides, lithium cobalt composite oxides, lithium manganese composite oxides, lithium-manganese-nickel composite oxides; transitions of TiS 2 , FeS, MoS 2, etc. Metal sulfides; transition metal oxides such as MnO, V 2 O 5 , V 6 O 13 , TiO 2 , olivine type lithium phosphorus oxide and the like can be mentioned.
  オリビン型リチウムリン酸化物は、例えば、Ｍｎ、Ｃｒ、Ｃｏ、Ｃｕ、Ｎｉ、Ｖ、Ｍｏ、Ｔｉ、Ｚｎ、Ａｌ、Ｇａ、Ｍｇ、Ｂ、Ｎｂ、およびＦｅからなる群のうちの少なくとも１種の元素と、リチウムと、リンと、酸素とを含んでいる。これらの化合物はその特性を向上させるために一部の元素を部分的に他の元素に置換したものであってもよい。 The olivine-type lithium phosphorus oxide is, for example, at least one of the group consisting of Mn, Cr, Co, Cu, Ni, V, Mo, Ti, Zn, Al, Ga, Mg, B, Nb, and Fe. It contains elements, lithium, phosphorus, and oxygen. These compounds may be those in which some elements are partially replaced with other elements in order to improve their properties.
  これらの中でも、オリビン型リチウム鉄リン酸化物、リチウムコバルト複合酸化物、リチウムニッケル複合酸化物、リチウムマンガン複合酸化物、リチウム－マンガン－ニッケル複合酸化物が好ましい。これらの正極活物質は作用電位が高いことに加えて容量も大きく、大きなエネルギー密度を有する。 Among these, olivine-type lithium iron phosphorus oxide, lithium cobalt composite oxide, lithium nickel composite oxide, lithium manganese composite oxide, and lithium-manganese-nickel composite oxide are preferable. In addition to having a high working potential, these positive electrode active materials have a large capacity and a large energy density.
  正極集電体としては、例えばアルミニウム箔を用いることができる。 As the positive electrode current collector, for example, an aluminum foil can be used.
  本発明のリチウムイオン二次電池に使用される正極は、公知の製造方法により製造することができる。 The positive electrode used in the lithium ion secondary battery of the present invention can be manufactured by a known manufacturing method.
  リチウムイオン二次電池に使用される電解質としては、公知のリチウム塩がいずれも使用でき、活物質の種類に応じて選択すればよい。例えば、ＬｉＣｌＯ４、ＬｉＢＦ６、ＬｉＰＦ６、ＬｉＣＦ３ＳＯ３、ＬｉＣＦ３ＣＯ２、ＬｉＡｓＦ６、ＬｉＳｂＦ６、ＬｉＢ１０Ｃｌ１０、ＬｉＡｌＣｌ４、ＬｉＣｌ、ＬｉＢｒ、ＬｉＢ（Ｃ２Ｈ５）４、ＣＦ３ＳＯ３Ｌｉ、ＣＨ３ＳＯ３Ｌｉ、ＬｉＣＦ３ＳＯ３、ＬｉＣ４Ｆ９ＳＯ３、Ｌｉ（ＣＦ３ＳＯ２）２Ｎ、低級脂肪酸カルボン酸リチウム等が挙げられる。 As the electrolyte used in the lithium ion secondary battery, any known lithium salt can be used and may be selected according to the type of active material. For example, LiClO 4, LiBF 6, LiPF 6, LiCF 3 SO 3, LiCF 3 CO 2, LiAsF 6, LiSbF 6, LiB 10 Cl 10, LiAlCl 4, LiCl, LiBr, LiB (C 2 H 5) 4, CF 3 Examples thereof include SO 3 Li, CH 3 SO 3 Li, LiCF 3 SO 3 , LiC 4 F 9 SO 3 , Li (CF 3 SO 2 ) 2 N, and lower fatty acid lithium carboxylate.
  電解質を溶解する溶媒としては、電解質を溶解させる液体成分として通常用いられるものであれば特に限定されるものではなく、エチレンカーボネート（ＥＣ）、プロピレンカーボネート（ＰＣ）、ブチレンカーボネート（ＢＣ）、ジメチルカーボネート（ＤＭＣ）、ジエチルカーボネート（ＤＥＣ）、メチルエチルカーボネート（ＭＥＣ）、ビニレンカーボネート（ＶＣ）等のカーボネート類；γ－ブチロラクトン、γ－バレロラクトン等のラクトン類；トリメトキシメタン、１，２－ジメトキシエタン、ジエチルエーテル、２－エトキシエタン、テトラヒドロフラン、２－メチルテトラヒドロフラン等のエーテル類；ジメチルスルホキシド等のスルホキシド類；１，３－ジオキソラン、４－メチル－１，３－ジオキソラン等のオキソラン類；アセトニトリル、ニトロメタン、ホルムアミド、ジメチルホルムアミド等の含窒素類；ギ酸メチル、酢酸メチル、酢酸エチル、酢酸ブチル、プロピオン酸メチル、プロピオン酸エチル等の有機酸エステル類；リン酸トリエステルやジグライム類；トリグライム類；スルホラン、メチルスルホラン等のスルホラン類；３－メチル－２－オキサゾリジノン等のオキサゾリジノン類；１，３－プロパンスルトン、１，４－ブタンスルトン、ナフタスルトン等のスルトン類等が挙げられる。これらは、１種単独で使用してもよいし、２種以上を組み合わせて使用してもよい。 The solvent for dissolving the electrolyte is not particularly limited as long as it is usually used as a liquid component for dissolving the electrolyte, and ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), and dimethyl carbonate. Carbonates such as (DMC), diethyl carbonate (DEC), methyl ethyl carbonate (MEC), vinylene carbonate (VC); lactones such as γ-butyrolactone and γ-valerolactone; trimethoxymethane, 1,2-dimethoxyethane , Diethyl ether, 2-ethoxyethane, tetrahydrofuran, 2-methyl tetrahydrofuran and other ethers; dimethylsulfoxide and other sulfoxides; 1,3-dioxolane, 4-methyl-1,3-dioxolane and other oxolanes; acetonitrile, nitromethane , Nitrogen-containing substances such as formamide and dimethylformamide; organic acid esters such as methyl formate, methyl acetate, ethyl acetate, butyl acetate, methyl propionate and ethyl propionate; phosphate triesters and jiglimes; triglimes; sulfolanes, Sulfolans such as methyl sulfolane; oxazolidinones such as 3-methyl-2-oxazolidinone; sulton species such as 1,3-propane sulton, 1,4-butane sulton, and nafta sulton can be mentioned. These may be used individually by 1 type, or may be used in combination of 2 or more type.
  セパレータとしては、例えば、多孔性セパレータが挙げられる。セパレータの形態は、膜、フィルム、不織布等が挙げられる。 Examples of the separator include a porous separator. Examples of the form of the separator include a film, a film, and a non-woven fabric.
  多孔性セパレータとしては、例えば、ポリプロピレン系、ポリエチレン系等のポリオレフィン系多孔性セパレータ；ポリビニリデンフルオリド、ポリエチレンオキシド、ポリアクリロニトリル、ポリビニリデンフルオリドヘキサフルオロプロピレン共重合体等により形成された多孔性セパレータが挙げられる。 Examples of the porous separator include polyolefin-based porous separators such as polypropylene and polyethylene; polyvinylidene fluoride, polyethylene oxide, polyacrylonitrile, polyvinylidene fluoride hexafluoropropylene copolymer and the like. Can be mentioned.
　以下、実施例により本発明をより具体的に説明するが、本発明はこれらの実施例により限定されるものではない。 Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.
製造例１（ＮＤ－１）
以下工程を経て、ＮＤ粒子水分散液を作製した。
（１）生成工程
　まず、成形された爆薬に電気***が装着されたものを爆轟用の耐圧性容器（鉄製、容積：１５ｍ３）の内部に設置して容器を密閉した。爆薬としては、ＴＮＴとＲＤＸとの混合物（ＴＮＴ／ＲＤＸ（質量比）＝５０／５０）０．５０ｋｇを使用した。次に、電気***を起爆させ、容器内で爆薬を爆轟させた。次に、室温で２４時間放置して、容器およびその内部を降温させた。この放冷の後、容器の内壁に付着しているＮＤ粒子粗生成物（上記爆轟法で生成したＮＤ粒子の凝着体と煤を含む）を回収してＮＤ粒子粗生成物を得た。 Production Example 1 (ND-1)
An ND particle aqueous dispersion was prepared through the following steps.
(1) Generation step First, a molded explosive equipped with an electric detonator was placed inside a pressure-resistant container (made of iron, volume: 15 m 3 ) for detonation, and the container was sealed. As the explosive, 0.50 kg of a mixture of TNT and RDX (TNT / RDX (mass ratio) = 50/50) was used. Next, the electric detonator was detonated and the explosive was detonated in the container. Next, the container and its inside were cooled by leaving it at room temperature for 24 hours. After this cooling, the ND particle crude product adhering to the inner wall of the container (including the ND particle coagulant and soot produced by the detonation method) was recovered to obtain the ND particle crude product. ..
（２）酸処理工程
　次に、上記工程で得たＮＤ粒子粗生成物に対して酸処理を行った。具体的には、当該ＮＤ粒子粗生成物２００ｇに６Ｌの１０質量％塩酸を加えて得られたスラリーに対し、常圧条件での還流下で１時間の加熱処理（加熱温度：８５～１００℃）を行った。次に、冷却後、デカンテーションにより、固形分（ＮＤ凝着体と煤を含む）の水洗を行った。沈殿液のｐＨが低ｐＨ側から２に至るまで、デカンテーションによる当該固形分の水洗を反復して行った。 (2) Acid Treatment Step Next, the ND particle crude product obtained in the above step was subjected to acid treatment. Specifically, the slurry obtained by adding 6 L of 10% by mass hydrochloric acid to 200 g of the crude ND particle product is heat-treated for 1 hour under reflux under normal pressure conditions (heating temperature: 85 to 100 ° C.). ) Was performed. Next, after cooling, the solid content (including the ND adherent and soot) was washed with water by decantation. The solid content was repeatedly washed with water by decantation until the pH of the precipitate was from the low pH side to 2.
（３）酸化処理工程
　次に、混酸処理を行った。具体的には、酸処理後のデカンテーションを経て得た沈殿液（ＮＤ凝着体を含む）に、６Ｌの９８質量％硫酸水溶液と１Ｌの６９質量％硝酸水溶液とを加えてスラリーとした後、このスラリーに対し、常圧条件及び還流下において４８時間の加熱処理（加熱温度：１４０～１６０℃）を行った。次に、冷却後、デカンテーションにより、固形分（ＮＤ凝着体を含む）の水洗を行った。水洗当初の上澄み液は着色していたが、上澄み液が目視で透明になるまで、デカンテーションによる当該固形分の水洗を反復して行った。 (3) Oxidation Treatment Step Next, a mixed acid treatment was performed. Specifically, a 6 L 98% by mass sulfuric acid aqueous solution and a 1 L 69% by mass nitric acid aqueous solution are added to a precipitate (including an ND adhering body) obtained through decantation after acid treatment to form a slurry. , This slurry was heat-treated (heating temperature: 140 to 160 ° C.) for 48 hours under normal pressure conditions and reflux. Next, after cooling, the solid content (including the ND adherent) was washed with water by decantation. The supernatant was colored at the beginning of washing with water, but the solid content was repeatedly washed with water by decantation until the supernatant was visually transparent.
（４）乾燥工程
　次に、上述の水洗処理を経て得られたＮＤ粒子含有液１０００ｍＬを、噴霧乾燥装置（商品名「スプレードライヤー Ｂ－２９０」、日本ビュッヒ（株）製）を使用して噴霧乾燥に付した。これにより、５０ｇのＮＤ粉体を得た。 (4) Drying step Next, 1000 mL of the ND particle-containing liquid obtained through the above-mentioned washing treatment is sprayed using a spray drying device (trade name "Spray Dryer B-290", manufactured by Nippon Buch Co., Ltd.). It was dried. As a result, 50 g of ND powder was obtained.
（５）酸素酸化工程
　次に、上述のようにして得られたＮＤ粉体４.５ｇをガス雰囲気炉（商品名「ガス雰囲気チューブ炉 ＫＴＦ０４５Ｎ１」、光洋サーモシステム（株）製）の炉心管内に静置し、炉心管に窒素ガスを流速１Ｌ／分で３０分間通流させ続けた後、通流ガスを窒素から酸素と窒素との混合ガスへと切り替えて当該混合ガスを流速１Ｌ／分で炉心管に通流させ続けた。混合ガス中の酸素濃度は４体積％である。混合ガスへの切り替えの後、炉内を加熱設定温度たる４００℃まで昇温させた。昇温速度については、加熱設定温度より２０℃低い３８０℃までは１０℃／分とし、その後の３８０℃から４００℃までは１℃／分とした。そして、炉内の温度条件を４００℃に維持しつつ、炉内のＮＤ粉体について酸素酸化処理を行った。処理時間は３時間とした。酸素酸化処理後、下記ＦＴ－ＩＲ分析により、ＮＤ粒子におけるカルボキシ基等の含酸素官能基の評価を行った。この分析で得られたスペクトルより、Ｃ＝Ｏ伸縮振動に帰属する１７８０ｃｍ-1付近の吸収がメインピークとして検出された。このことから、前記ＮＤ粉体には、表面官能基としてカルボキシル基を有するＮＤ粒子（ＮＤ－ＣＯＯＨ）が主に含まれることが確認できた。 (5) Oxygen Oxidation Step Next, 4.5 g of the ND powder obtained as described above was placed in the core tube of a gas atmosphere furnace (trade name "gas atmosphere tube furnace KTF045N1", manufactured by Koyo Thermo System Co., Ltd.). After leaving to stand and allowing nitrogen gas to flow through the core tube at a flow rate of 1 L / min for 30 minutes, the flow gas is switched from nitrogen to a mixed gas of oxygen and nitrogen, and the mixed gas is flowed at a flow rate of 1 L / min. Continued to flow through the core tube. The oxygen concentration in the mixed gas is 4% by volume. After switching to the mixed gas, the temperature inside the furnace was raised to 400 ° C., which is the set heating temperature. The heating rate was 10 ° C./min up to 380 ° C., which is 20 ° C. lower than the set heating temperature, and 1 ° C./min from 380 ° C. to 400 ° C. thereafter. Then, while maintaining the temperature condition in the furnace at 400 ° C., the ND powder in the furnace was subjected to oxygen oxidation treatment. The processing time was 3 hours. After the oxygen oxidation treatment, the oxygen-containing functional groups such as the carboxy group in the ND particles were evaluated by the following FT-IR analysis. From the spectrum obtained by this analysis, absorption near 1780 cm-1 attributable to C = O expansion and contraction vibration was detected as the main peak. From this, it was confirmed that the ND powder mainly contained ND particles (ND-COOH) having a carboxyl group as a surface functional group.
（６）解砕工程
　まず、酸素酸化工程を経たＮＤ粉体０．３ｇと純水２９．７ｍＬとを５０ｍＬのサンプル瓶内で混合し、スラリー約３０ｍＬを得た。次に、当該スラリーについて、１Ｎの水酸化ナトリウム水溶液の添加によりｐＨを調整した後、超音波照射器（商品名「超音波洗浄機 ＡＳ－３」、アズワン（ＡＳ ＯＮＥ）社製）を使用して２時間の超音波照射を行った。この後、ビーズミリング装置（商品名「並列四筒式サンドグラインダー ＬＳＧ－４Ｕ－２Ｌ型」、アイメックス（株）製）を使用してビーズミリングを行った。具体的には、１００ｍＬのミル容器であるベッセル（アイメックス（株）製）に超音波照射後のスラリー３０ｍＬと直径３０μｍのジルコニアビーズとを封入し、装置を駆動させてビーズミリングを実行した。このビーズミリングにおいて、ジルコニアビーズの投入量は、ミル容器の容積に対して約３３％であり、ミル容器の回転速度は２５７０ｒｐｍであり、ミリング時間は２時間である。 (6) Crushing Step First, 0.3 g of ND powder and 29.7 mL of pure water that had undergone the oxygen oxidation step were mixed in a 50 mL sample bottle to obtain about 30 mL of slurry. Next, after adjusting the pH of the slurry by adding a 1N aqueous sodium hydroxide solution, an ultrasonic irradiator (trade name "ultrasonic cleaner AS-3", manufactured by AS ONE) was used. Ultrasonic irradiation was performed for 2 hours. After that, bead milling was performed using a bead milling device (trade name "parallel four-cylinder sand grinder LSG-4U-2L type", manufactured by IMEX Co., Ltd.). Specifically, 30 mL of the slurry after ultrasonic irradiation and zirconia beads having a diameter of 30 μm were sealed in a 100 mL mill container, Vessel (manufactured by Imex Co., Ltd.), and the apparatus was driven to perform bead milling. In this bead milling, the input amount of zirconia beads is about 33% with respect to the volume of the mill container, the rotation speed of the mill container is 2570 rpm, and the milling time is 2 hours.
　次に、解砕工程を経たスラリーについて、遠心分離装置を使用して遠心分離処理を行った（分級操作）。この遠心分離処理における遠心力は２００００×ｇとし、遠心時間は１０分間とした。 Next, the slurry that had undergone the crushing step was centrifuged using a centrifuge device (classification operation). The centrifugal force in this centrifugation treatment was 20000 × g, and the centrifugation time was 10 minutes.
　次に、当該遠心分離処理を経たＮＤ粒子含有溶液の上澄み液２５ｍＬを回収し、ＮＤ粒子水分散液（ＮＤ１）を得た。ＮＤ粒子水分散液中のＮＤ粒子濃度は１１．８ｇ／Ｌであった。また、卓上型ｐＨメーター（商品名「ＬＡＱＵＡａｃｔ　Ｄ－７１ＡＣ」、堀場製作所（株）製）を使用して測定したところ、ｐＨは９.３３であった。粒径Ｄ５０は３．９７ｎｍ、粒径Ｄ９０は７．２０ｎｍ、ゼータ電位は－４２ｍＶであった。 Next, 25 mL of the supernatant of the ND particle-containing solution that had undergone the centrifugation treatment was recovered to obtain an ND particle aqueous dispersion (ND1). The ND particle concentration in the ND particle aqueous dispersion was 11.8 g / L. Further, when measured using a desktop pH meter (trade name "LAQUAact D-71AC", manufactured by HORIBA, Ltd.), the pH was 9.33. The particle size D50 was 3.97 nm, the particle size D90 was 7.20 nm, and the zeta potential was −42 mV.
　得られたＮＤ粒子水分散液中の粒子について、Ｘ線回折装置（商品名「ＳｍａｒｔＬａｂ」、リガク社製）を使用して結晶構造解析を行った。その結果、ダイヤモンドの解析ピーク位置、すなわち、ダイヤモンド結晶の（１１１）面からの回折ピーク位置に強いピークが認められた。これにより、得られた粒子がダイヤモンドの粒子であることが確認できた。 Crystal structure analysis was performed on the particles in the obtained ND particle aqueous dispersion using an X-ray diffractometer (trade name "SmartLab", manufactured by Rigaku Co., Ltd.). As a result, a strong peak was observed at the analysis peak position of diamond, that is, the diffraction peak position from the (111) plane of the diamond crystal. From this, it was confirmed that the obtained particles were diamond particles.
　得られたＮＤ粒子水分散液に対して、超純水を加えＮＤの固形分濃度が０．３ｗｔ％になるように調整し、電極の作製を実施した。 Ultrapure water was added to the obtained aqueous dispersion of ND particles to adjust the solid content concentration of ND to 0.3 wt%, and electrodes were prepared.
製造例２
（１）修飾工程
　上記製造例１で得られたＮＤ粒子水分散液を、エバポレーターを使用して乾燥させ、黒色の乾燥粉体を得た。つづいて得られたナノダイヤモンドの粉体０．１ｇとエチレングリコール１３．５ｇとを混合して得た分散液を窒素雰囲気下で７０℃まで加熱した。この分散液に、７０℃を維持しながら、グリシドール１３．５ｇを１時間かけて滴下し、滴下終了後、同温度で１０時間熟成した。熟成終了後、室温まで冷却し、反応混合液に該反応混合液と同量の水を加えて反応を停止させた。その後、この反応混合液をＵＦ膜（Ｍｉｌｌｉｐｏｒｅ社製、商品名「Ａｍｉｃｏｎ　Ｂｉｏｓｅｐａｒａｔｉｏｎｓ」、ポリエーテルスルホン製、分画分子量３００００）を用いて精製した。透過（膜を用いて固液分離）－希釈［残った上層（有価物）に水を添加］を繰り返し、トータルの希釈倍率が１００万倍となったところで精製を終了した。こうして、表面がポリグリセリン鎖を含む基により修飾された表面修飾ナノダイヤモンドの分散液（ＮＤ－２）を得た。上記で得られた表面修飾ナノダイヤモンド分散液について、動的光散乱法によって表面修飾ナノダイヤモンドの粒度分布を測定したところ、粒径Ｄ１０は２３ｎｍ、Ｄ５０（メディアン径）は４０ｎｍ、Ｄ９０は７８ｎｍであった。上記で得られた表面修飾ナノダイヤモンド分散液中の表面修飾ナノダイヤモンドについて、修飾基の修飾率を測定した結果、０．７であった。 Manufacturing example 2
(1) Modification Step The ND particle aqueous dispersion obtained in Production Example 1 was dried using an evaporator to obtain a black dry powder. Subsequently, a dispersion obtained by mixing 0.1 g of the obtained nanodiamond powder and 13.5 g of ethylene glycol was heated to 70 ° C. under a nitrogen atmosphere. 13.5 g of glycidol was added dropwise to this dispersion over 1 hour while maintaining 70 ° C., and after completion of the addition, the mixture was aged at the same temperature for 10 hours. After completion of aging, the mixture was cooled to room temperature, and the same amount of water as the reaction mixture was added to the reaction mixture to stop the reaction. Then, this reaction mixture was purified using a UF membrane (manufactured by Millipore, trade name "Amicon Bioseparations", manufactured by polyether sulfone, molecular weight cut off of 30,000). Permeation (solid-liquid separation using a membrane) -dilution [adding water to the remaining upper layer (valuable material)] was repeated, and purification was completed when the total dilution ratio reached 1 million times. In this way, a dispersion liquid (ND-2) of surface-modified nanodiamonds whose surface was modified with a group containing a polyglycerin chain was obtained. When the particle size distribution of the surface-modified nanodiamonds was measured by the dynamic light scattering method for the surface-modified nanodiamond dispersion obtained above, the particle size D 10 was 23 nm, D 50 (median diameter) was 40 nm, and D 90 was. It was 78 nm. The modification rate of the modifying group of the surface-modified nanodiamond in the surface-modified nanodiamond dispersion obtained above was measured and found to be 0.7.
　得られたＮＤ粒子水分散液に対して、超純水を加えＮＤの固形分濃度が０．３ｗｔ％になるように調整し、電極の作製を実施した。 Ultrapure water was added to the obtained aqueous dispersion of ND particles to adjust the solid content concentration of ND to 0.3 wt%, and electrodes were prepared.
比較製造例１
　製造例１の乾燥工程で得られたＮＤ粉体（ＮＤ－３）に対して、超純水を加えＮＤの固形分濃度が０．３ｗｔ％になるように調整し、電極の作製を実施した。 Comparative manufacturing example 1
Ultrapure water was added to the ND powder (ND-3) obtained in the drying step of Production Example 1 to adjust the solid content concentration of ND to 0.3 wt%, and electrodes were manufactured. ..
＜ＦＴ－ＩＲ分析条件＞   
ＦＴ－ＩＲ装置（商品名「Ｓｐｅｃｔｒｕｍ４００型ＦＴ－ＩＲ」、（株）パーキンエルマージャパン製）を使用して、フーリエ変換赤外分光分析（ＦＴ－ＩＲ）を行った。本測定においては、試料を真空雰囲気下で１５０℃に加熱しつつ赤外吸収スペクトルを測定した。真空雰囲気下の加熱には、エス・ティ・ジャパン社製のＭｏｄｅｌ－ＨＣ９００型Ｈｅａｔ ＣｈａｍｂｅｒとＴＣ－１００ＷＡ型Ｔｈｅｒｍｏ Ｃｏｎｔｒｏｌｌｅｒとを併用した。 <FT-IR analysis conditions>
Fourier Transform Infrared Spectroscopy (FT-IR) was performed using an FT-IR apparatus (trade name "Spectrum 400 type FT-IR", manufactured by Perkin Elmer Japan Co., Ltd.). In this measurement, the infrared absorption spectrum was measured while heating the sample to 150 ° C. in a vacuum atmosphere. For heating in a vacuum atmosphere, a Model-HC900 type Heat Chamber manufactured by ST Japan and a TC-100WA type Thermo Controller were used in combination.
＜固形分濃度＞
　上述のようにして得られた表面修飾ナノダイヤモンド分散液について、以下のようにして固形分濃度を測定した。すなわち、ビーカーの上にテフロン（登録商標）シートを張り、その上に、上記で得られた分散液（サンプル）を数ｇのせて、２５０℃サンドバスで数時間処理し、ある程度乾燥したら７０℃で一晩真空乾燥させ、残った固形分の重さから固形分濃度を求めた。 <Solid content concentration>
The solid content concentration of the surface-modified nanodiamond dispersion obtained as described above was measured as follows. That is, a Teflon (registered trademark) sheet is placed on a beaker, a few g of the dispersion liquid (sample) obtained above is placed on the beaker, treated in a 250 ° C. sand bath for several hours, and dried to some extent at 70 ° C. The solid content was vacuum-dried overnight, and the solid content concentration was determined from the weight of the remaining solid content.
＜粒径測定＞
  上述のようにして得られた表面修飾ナノダイヤモンド分散液について、動的光散乱法によって表面修飾ナノダイヤモンドの粒度分布を測定した。具体的には、マイクロトラックベル社製の装置（商品名「Nanotrac Wave II」）を使用して、表面修飾ナノダイヤモンドの粒度分布を動的光散乱法（非接触後方散乱法）によって測定した。 <Measurement of particle size>
With respect to the surface-modified nanodiamond dispersion obtained as described above, the particle size distribution of the surface-modified nanodiamond was measured by a dynamic light scattering method. Specifically, the particle size distribution of surface-modified nanodiamonds was measured by a dynamic light scattering method (non-contact backscattering method) using an apparatus manufactured by Microtrac Bell (trade name "Nanotrac Wave II").
＜修飾基の修飾率＞
　上述のようにして得られた表面修飾ナノダイヤモンド分散液中の表面修飾ナノダイヤモンド（前記分散液を乾燥した固体）について、ＴＧ／ＤＴＡ（石英パン、３０－８００℃、昇温速度２０℃／ｍｉｎ）を用いて、ナノダイヤモンド（ＮＤ）に対する修飾基の比率（修飾基重量／ＮＤ重量）を求めた。  <Modification rate of modifying group>
Regarding the surface-modified nanodiamond (solid obtained by drying the dispersion) in the surface-modified nanodiamond dispersion obtained as described above, TG / DTA (quartz pan, 30-800 ° C., heating rate 20 ° C./min) ) Was used to determine the ratio of modifying groups to nanodiamond (ND) (modifying group weight / ND weight).
実施例１～２及び比較例１
（負極電極用スラリーの組成）
黒鉛、アセチレンブラック、50wt%SBR、1.5wt%CMC水溶液、0.3wt%ND水分散液を、94.7/3/1/1/0.3の比率で混合し電極を作製した（固形分濃度36.41wt%）。黒鉛に対してND固形分が約0.3wt%となるように調整した。この時、異なる3種類のNDをそれぞれ用いることで3種類の電極を作製した（表１）。 Examples 1 and 2 and Comparative Example 1
(Composition of slurry for negative electrode)
An electrode was prepared by mixing graphite, acetylene black, 50 wt% SBR, 1.5 wt% CMC aqueous solution, and 0.3 wt% ND aqueous dispersion at a ratio of 94.7 / 3/1/1 / 0.3 (solid content concentration 36.41 wt%). .. The ND solid content was adjusted to be about 0.3 wt% with respect to graphite. At this time, three types of electrodes were produced by using three different types of NDs (Table 1).
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
（負極電極用スラリー組成物の作製）
0.3wt%ND水分散液（3.0 g）と1.5wt%CMC水溶液（0.71 g）を自転公転撹拌機で混合し、ND-CMC水分散液（スラリーA）を作製した。別の容器に黒鉛（2.55 g）、アセチレンブラック（0.08 g）、残りの1.5wt%CMC水溶液（1.00 g）を加え、自転公転撹拌機で混合しスラリーBを作製した。これらスラリーA、Bを自転公転撹拌機で混合した後、50wt%SBR水分散液（0.055 g）を加え、さらに自転公転撹拌機で混合することで負極用スラリー組成物を作製した。 (Preparation of slurry composition for negative electrode)
A 0.3 wt% ND aqueous dispersion (3.0 g) and a 1.5 wt% CMC aqueous solution (0.71 g) were mixed with a rotating revolution stirrer to prepare an ND-CMC aqueous dispersion (slurry A). Graphite (2.55 g), acetylene black (0.08 g), and the remaining 1.5 wt% CMC aqueous solution (1.00 g) were added to another container and mixed with a rotating revolution stirrer to prepare slurry B. After mixing these slurries A and B with a rotation / revolution agitator, a 50 wt% SBR aqueous dispersion (0.055 g) was added and further mixed with a rotation / revolution agitator to prepare a slurry composition for a negative electrode.
（リチウムイオン二次電池用負極電極の作製）
集電体として厚さ約20 μmの銅箔を準備した。上記で作製したスラリー組成物を、バーコーダーを用い、設定値10 mil（254 μm）で銅箔の片面に塗布し、約60 ℃で30分間オーブン内にて乾燥することでリチウムイオン二次電池用電極を作製した。 (Manufacture of negative electrode for lithium ion secondary battery)
A copper foil with a thickness of about 20 μm was prepared as a current collector. The slurry composition prepared above is applied to one side of a copper foil at a set value of 10 mil (254 μm) using a bar coder, and dried in an oven at about 60 ° C. for 30 minutes to form a lithium ion secondary battery. A electrode for use was prepared.
（電極表面観察）
上記で得られた3種類のグラファイト電極に関して、電極中に分散しているNDの平均分散粒子径をＴＥＭ観察によって算出した。３００個のND粒子について、ND粒子（凝集体として存在）の端と端を結んだ直線が最も長くなる距離を分散粒子径とし平均値を求めた。 (Observation of electrode surface)
For the three types of graphite electrodes obtained above, the average dispersed particle size of ND dispersed in the electrodes was calculated by TEM observation. For 300 ND particles, the distance at which the longest straight line connecting the ends of the ND particles (existing as an agglomerate) was taken as the dispersed particle diameter, and the average value was calculated.

Claims (8)

  1. ナノダイヤモンド（ＮＤ）粒子が増粘剤を含む水性溶媒に分散した、ナノダイヤモンド水性分散組成物であって、前記ＮＤ粒子の平均分散粒子径が５～１００ｎｍである、ナノダイヤモンド水性分散組成物。 A nanodiamond aqueous dispersion composition in which nanodiamond (ND) particles are dispersed in an aqueous solvent containing a thickener, wherein the average dispersed particle size of the ND particles is 5 to 100 nm.
  2. ナノダイヤモンドの一次粒子は球状、楕円体状或いは多面体状である、請求項１に記載のナノダイヤモンド水性分散組成物。 The nanodiamond aqueous dispersion composition according to claim 1, wherein the primary particles of nanodiamond are spherical, ellipsoidal, or polyhedral.
  3. 増粘剤がカルボキシメチルセルロースナトリウム（ＣＭＣ）である、請求項１又は２に記載のナノダイヤモンド水性分散組成物。 The nanodiamond aqueous dispersion composition according to claim 1 or 2, wherein the thickener is sodium carboxymethyl cellulose (CMC).
  4. ＮＤ一次粒子の平均粒子径が１０ｎｍ以下である、請求項１～３のいずれか１項に記載のナノダイヤモンド水性分散組成物。 The nanodiamond aqueous dispersion composition according to any one of claims 1 to 3, wherein the average particle size of the ND primary particles is 10 nm or less.
  5. 請求項１～４のいずれか１項に記載のナノダイヤモンド水性分散組成物と負極活物質及びバインダーを含むことを特徴とするリチウムイオン二次電池用負極ペースト。 A negative electrode paste for a lithium ion secondary battery, which comprises the nanodiamond aqueous dispersion composition according to any one of claims 1 to 4, a negative electrode active material, and a binder.
  6. 請求項５に記載の負極ペーストを用いて作製されることを特徴とするリチウムイオン二次電池用負極。 A negative electrode for a lithium ion secondary battery, which is produced by using the negative electrode paste according to claim 5.
  7. リチウムイオン二次電池用負極中におけるＮＤ粒子の平均分散粒子径が５～１００ｎｍである、請求項６記載のリチウムイオン二次電池用負極。 The negative electrode for a lithium ion secondary battery according to claim 6, wherein the average dispersed particle size of the ND particles in the negative electrode for a lithium ion secondary battery is 5 to 100 nm.
  8. 請求項６に記載の負極と正極と電解質を備えたリチウムイオン二次電池。 A lithium ion secondary battery comprising the negative electrode, the positive electrode, and the electrolyte according to claim 6.
PCT/JP2021/010941 2020-03-30 2021-03-17 Nanodiamond aqueous dispersion composition, negative electrode paste, negative electrode, and lithium-ion secondary cell WO2021200177A1 (en)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2009091234A (en) * 2007-09-18 2009-04-30 Tokyo Univ Of Science Conductive diamond film-formed substrate, and method for production of the substrate
WO2010053200A1 (en) * 2008-11-10 2010-05-14 株式会社エクォス・リサーチ Positive electrode for secondary battery, secondary battery using same, collector, and battery using the collector
JP2017115009A (en) * 2015-12-24 2017-06-29 日華化学株式会社 Water dispersion, coating liquid and method for producing transmission type screen

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2009091234A (en) * 2007-09-18 2009-04-30 Tokyo Univ Of Science Conductive diamond film-formed substrate, and method for production of the substrate
WO2010053200A1 (en) * 2008-11-10 2010-05-14 株式会社エクォス・リサーチ Positive electrode for secondary battery, secondary battery using same, collector, and battery using the collector
JP2017115009A (en) * 2015-12-24 2017-06-29 日華化学株式会社 Water dispersion, coating liquid and method for producing transmission type screen

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