WO2018051925A1 - Corps composite, électrode négative pour batteries secondaires au lithium-ion, et procédé de production de corps composite - Google Patents

Corps composite, électrode négative pour batteries secondaires au lithium-ion, et procédé de production de corps composite Download PDF

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Publication number
WO2018051925A1
WO2018051925A1 PCT/JP2017/032550 JP2017032550W WO2018051925A1 WO 2018051925 A1 WO2018051925 A1 WO 2018051925A1 JP 2017032550 W JP2017032550 W JP 2017032550W WO 2018051925 A1 WO2018051925 A1 WO 2018051925A1
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composite
negative electrode
lithium ion
ion secondary
fibrous carbon
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PCT/JP2017/032550
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English (en)
Japanese (ja)
Inventor
新井　進
雅裕 清水
恭平 桐畑
有信 堅田
秀悦 藤原
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日本ゼオン株式会社
国立大学法人信州大学
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Priority to JP2018539691A priority Critical patent/JP6975715B2/ja
Publication of WO2018051925A1 publication Critical patent/WO2018051925A1/fr

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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
    • C01B32/15—Nano-sized carbon materials
    • C01B32/152—Fullerenes
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D7/00—Electroplating characterised by the article coated
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
    • C25D5/54—Electroplating of non-metallic surfaces
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D3/00—Electroplating: Baths therefor
    • C25D3/02—Electroplating: Baths therefor from solutions
    • C25D3/30—Electroplating: Baths therefor from solutions of tin
    • C25D3/32—Electroplating: Baths therefor from solutions of tin characterised by the organic bath constituents used
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
    • 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 composite, a negative electrode for a lithium ion secondary battery, and a method for manufacturing the composite. Specifically, the present invention relates to a composite containing fibrous carbon nanostructures and tin fine particles. Moreover, this invention relates to the negative electrode for lithium ion secondary batteries provided with the said composite_body
  • Lithium ion secondary batteries are small and light, have high energy density, and can be repeatedly charged and discharged, and are used in a wide range of applications. Therefore, in recent years, improvement of battery members such as electrodes has been studied for the purpose of further improving the performance of lithium ion secondary batteries.
  • a negative electrode including a negative electrode active material layer including a negative electrode active material containing tin having a high theoretical capacity on a current collector has been studied (see, for example, Patent Documents 1 and 2). According to the negative electrodes described in Patent Documents 1 and 2, while increasing the capacity of the lithium ion secondary battery, the generation of cracks in the negative electrode active material during charge / discharge and the detachment from the current collector are suppressed. It has been reported that good cycle characteristics can be secured.
  • JP 2015-43309 A Japanese Patent No. 5275702
  • an object of the present invention is to provide means for advantageously solving the above-described improvements.
  • the present inventor has intensively studied to achieve the above object. Then, the present inventor uses a composite containing fibrous carbon nanostructures and fine particles having an average particle diameter of a predetermined value or less and made of tin as a negative electrode active material layer, so that a lithium ion secondary battery is obtained. The present inventors have found that the capacity can be increased and the lithium ion secondary battery can exhibit sufficiently excellent cycle characteristics, and the present invention has been completed.
  • the present invention aims to advantageously solve the above-mentioned problems, and the composite of the present invention contains fibrous carbon nanostructures and tin fine particles having an average particle diameter of 10 ⁇ m or less. It is characterized by. If a fibrous carbon nanostructure and a composite containing tin fine particles having an average particle size of the above value or less are used as the negative electrode active material layer, the capacity of the lithium ion secondary battery can be increased and the cycle characteristics can be sufficiently improved. it can.
  • tin fine particles refers to particles composed of tin and having a particle diameter of 100 ⁇ m or less.
  • the particle diameter of the tin fine particles is determined by observing the tin fine particles with, for example, a field emission scanning electron microscope (FE-SEM), and measuring the length of a line segment connecting two points on the outer edge of the tin fine particles. It is obtained by measuring the maximum length.
  • the “average particle diameter” of the tin fine particles can be calculated as an average value of the particle diameters of 100 randomly selected tin fine particles.
  • the composite of the present invention preferably has a structure in which the tin fine particles are present inside a carbon matrix containing the fibrous carbon nanostructure. If tin fine particles exist inside the carbon matrix composed of fibrous carbon nanostructures, the desorption of tin fine particles from the fibrous carbon nanostructures can be suppressed, and the cycle characteristics of the lithium ion secondary battery can be reduced. Further improvement can be achieved.
  • the “inside of the carbon matrix” means an inner portion other than the outermost surface of the carbon matrix, and “fine particles exist inside the carbon matrix including the fibrous carbon nanostructure”. This can be confirmed from the presence of tin fine particles embedded in a carbon matrix composed of fibrous carbon nanostructures when the cross section of the composite is observed with, for example, FE-SEM.
  • the fibrous carbon nanostructure includes a carbon nanotube. If the fibrous carbon nanostructure containing carbon nanotubes is used, the cycle characteristics of the lithium ion secondary battery can be further improved.
  • the fibrous carbon nanostructure has a shape in which a t-plot obtained from an adsorption isotherm is convex upward.
  • complex of this invention can be used as an object for lithium ion secondary battery negative electrodes.
  • the negative electrode for lithium ion secondary batteries of this invention is equipped with the negative electrode active material layer, and the said negative electrode active material layer is the composite_body
  • the composite described above is used as the negative electrode active material layer, the capacity of the lithium ion secondary battery can be increased and the cycle characteristics can be sufficiently improved.
  • the present invention aims to advantageously solve the above-described problems, and a method for producing a composite according to the present invention is a method for producing any of the above-described composites, wherein the fibrous
  • the carbon film including the carbon nanostructure includes a step of performing a plating process using a plating solution including a tin-containing compound. If the carbon film is plated using a plating solution containing a tin-containing compound, any of the above-described composites containing tin fine particles can be efficiently produced.
  • the plating solution further includes a polyether-based surfactant and water. If such a plating solution is used, any of the above-described composites containing tin fine particles can be produced more efficiently. Moreover, according to the negative electrode for lithium ion secondary batteries using the obtained composite, the lithium ion secondary battery can exhibit more excellent cycle characteristics.
  • the density of the carbon film is 0.01 g / cm 3 or more 1.80 g / cm 3 or less. If a carbon film having a density within the above-described range is used, the strength of the obtained composite is ensured, and the lithium ion secondary battery negative electrode using the composite further improves the lithium ion secondary battery. Cycle characteristics can be exhibited.
  • a negative electrode for a lithium ion secondary battery capable of increasing the capacity of the lithium ion secondary battery and causing the lithium ion secondary battery to exhibit sufficiently excellent cycle characteristics. be able to.
  • the negative electrode for lithium ion secondary batteries of this invention while being able to increase capacity of a lithium ion secondary battery, the said lithium ion secondary battery can fully exhibit the cycling characteristics which were excellent.
  • the method for producing a composite of the present invention a composite capable of increasing the capacity of a lithium ion secondary battery and exhibiting sufficiently excellent cycle characteristics in the lithium ion secondary battery is efficiently produced. Can be manufactured well.
  • FIG. 6 is a graph showing an example of a t-plot of a sample having pores on the surface.
  • 3 is an FE-SEM photograph of a cross section of composite A obtained in an example.
  • the composite of the present invention is a material in which fibrous carbon nanostructures and tin fine particles are combined.
  • complex of this invention can be used for preparation of the negative electrode for lithium ion secondary batteries of this invention.
  • complex of this invention can be manufactured using the manufacturing method of the composite_body
  • the composite of the present invention includes at least a fibrous carbon nanostructure and tin fine particles having an average particle diameter of 10 ⁇ m or less, and includes components (other components) other than the fibrous carbon nanostructure and the tin fine particles. May be included.
  • the composite of the present invention contains tin fine particles, if the composite of the present invention is used as a negative electrode active material layer of a negative electrode for a lithium ion secondary battery, the tin fine particles function as a negative electrode active material and are lithium ion secondary.
  • the capacity of the battery can be increased.
  • the tin fine particles in the composite of the present invention have an average particle diameter of 10 ⁇ m or less, even if the tin fine particles are repeatedly expanded and contracted by charging / discharging of the lithium ion secondary battery, the tin fine particles The stress applied to is sufficiently small. Therefore, generation of cracks and desorption from the current collector of tin fine particles, which are the negative electrode active material, are suppressed, and excellent cycle characteristics can be exhibited in the lithium ion secondary battery.
  • the fibrous carbon nanostructure is not particularly limited.
  • carbon nanotubes CNT
  • vapor-grown carbon fibers C fibers obtained by carbonizing organic fibers, and cut products thereof are used. Can do. These may be used individually by 1 type and may use 2 or more types together.
  • the fibrous carbon nanostructure it is more preferable to use a fibrous carbon nanostructure including carbon nanotubes. If a fibrous carbon nanostructure containing carbon nanotubes is used, physical properties such as conductivity of the composite can be improved, and more excellent cycle characteristics can be exhibited in the lithium ion secondary battery.
  • a fibrous carbon nanostructure containing CNT it may not be specifically limited but what consists only of CNT may be used, and the mixture of CNT and fibrous carbon nanostructures other than CNT is used. May be.
  • the CNT in the fibrous carbon nanostructure is not particularly limited, and single-walled carbon nanotubes and / or multi-walled carbon nanotubes can be used.
  • the CNT is preferably a single-walled to carbon-walled carbon nanotube, more preferably a single-walled carbon nanotube. If single-walled carbon nanotubes are used, the cycle characteristics of the lithium ion secondary battery can be further improved as compared with the case where multi-walled carbon nanotubes are used.
  • the fibrous carbon nanostructure from the viewpoint of further improving the cycle characteristics of the lithium ion secondary battery, it is preferable that the t-plot obtained from the adsorption isotherm shows a convex shape.
  • adsorption is a phenomenon in which gas molecules are removed from the gas phase to the solid surface, and is classified into physical adsorption and chemical adsorption based on the cause.
  • physical adsorption is used in the nitrogen gas adsorption method used for obtaining the t-plot. Normally, if the adsorption temperature is constant, the number of nitrogen gas molecules adsorbed on the fibrous carbon nanostructure increases as the pressure increases.
  • the plot of the relative pressure (ratio of adsorption equilibrium pressure P and saturated vapor pressure P0) on the horizontal axis and the amount of nitrogen gas adsorption on the vertical axis is called the “isothermal line”. Nitrogen gas adsorption while increasing the pressure The case where the amount is measured is referred to as an “adsorption isotherm”, and the case where the amount of nitrogen gas adsorption is measured while reducing the pressure is referred to as a “desorption isotherm”.
  • the t-plot is obtained by converting the relative pressure to the average thickness t (nm) of the nitrogen gas adsorption layer in the adsorption isotherm measured by the nitrogen gas adsorption method.
  • the average thickness t of the nitrogen gas adsorption layer is plotted against the relative pressure P / P0, and the average thickness t of the nitrogen gas adsorption layer corresponding to the relative pressure is obtained from the known standard isotherm and the above conversion is performed.
  • t-plot method by de Boer et al.
  • FIG. 1 a typical t-plot of a sample having pores on the surface is shown in FIG.
  • the growth of the nitrogen gas adsorption layer is classified into the following processes (1) to (3).
  • the following steps (1) to (3) change the slope of the t-plot as shown in FIG. (1)
  • Monomolecular adsorption layer formation process of nitrogen molecules on the entire surface
  • Multimolecular adsorption layer formation and capillary condensation filling process in the pores accompanying it (3) Apparent filling of the pores with nitrogen Formation process of multimolecular adsorption layer on non-porous surface
  • the t-plot of the preferred fibrous carbon nanostructure used in the present invention is located on a straight line passing through the origin in the region where the average thickness t of the nitrogen gas adsorption layer is small as shown in FIG.
  • the plot is shifted downward from the straight line and shows an upwardly convex shape.
  • the shape of the t-plot is such that the ratio of the internal specific surface area to the total specific surface area of the fibrous carbon nanostructure is large, and a large number of openings are formed in the carbon nanostructure constituting the fibrous carbon nanostructure. As a result, it is assumed that the fibrous carbon nanostructure exhibits excellent characteristics.
  • the bending point of the t-plot of the fibrous carbon nanostructure is preferably in a range satisfying 0.2 ⁇ t (nm) ⁇ 1.5, and 0.45 ⁇ t (nm) ⁇ 1.5. More preferably, it is in a range satisfying 0.55 ⁇ t (nm) ⁇ 1.0.
  • the “position of the bending point” is an intersection of the approximate line A in the process (1) described above and the approximate line B in the process (3) described above.
  • the fibrous carbon nanostructure preferably has a ratio (S2 / S1) of the internal specific surface area S2 to the total specific surface area S1 obtained from the t-plot of 0.05 or more and 0.30 or less. If S2 / S1 is 0.05 or more and 0.30 or less, it is possible to further improve the characteristics of the fibrous carbon nanostructure while sufficiently suppressing the formation of the bundle, so the cycle of the lithium ion secondary battery The characteristics can be further improved.
  • the total specific surface area S1 and the internal specific surface area S2 of the fibrous carbon nanostructure are not particularly limited, but individually, S1 is preferably 600 m 2 / g or more and 1400 m 2 / g or less, and 800 m 2.
  • the total specific surface area S1 and the internal specific surface area S2 of the fibrous carbon nanostructure can be obtained from the t-plot. Specifically, referring to the t-plot shown in FIG. 1, first, the total specific surface area S1 is determined from the slope of the approximate line in the process (1), and the external specific surface area S3 is determined from the slope of the approximate line in the process (3). Can be obtained respectively. Then, the internal specific surface area S2 can be calculated by subtracting the external specific surface area S3 from the total specific surface area S1.
  • the measurement of the adsorption isotherm of the fibrous carbon nanostructure, the creation of the t-plot, and the calculation of the total specific surface area S1 and the internal specific surface area S2 based on the analysis of the t-plot are, for example, commercially available measuring devices.
  • "BELSORP (registered trademark) -mini” manufactured by Nippon Bell Co., Ltd.).
  • the fibrous carbon nanostructure containing CNT is not subjected to CNT opening treatment, and the t-plot has a convex shape. More preferred.
  • the average diameter of the fibrous carbon nanostructure is preferably 0.5 nm or more, more preferably 1 nm or more, preferably 15 nm or less, and more preferably 10 nm or less.
  • the average diameter of the fibrous carbon nanostructure is 0.5 nm or more, a sufficient space is secured between the plurality of fibrous carbon nanostructures when the composite is prepared. Therefore, it can be set as the composite_body
  • the average diameter of fibrous carbon nanostructure is 15 nm or less, physical properties, such as electroconductivity of a composite, can be improved.
  • the lithium ion secondary battery can exhibit more excellent cycle characteristics.
  • the “average diameter of fibrous carbon nanostructures” can be determined by measuring the diameter (outer diameter) of 100 fibrous carbon nanostructures selected at random using a transmission electron microscope. And the average diameter of the fibrous carbon nanostructure containing CNT may be adjusted by changing the manufacturing method and manufacturing conditions of the fibrous carbon nanostructure containing CNT, or CNT obtained by a different manufacturing method. You may adjust by combining multiple types of fibrous carbon nanostructure containing this.
  • the aspect ratio (length / diameter) of the fibrous carbon nanostructure is preferably more than 10.
  • the aspect ratio of the fibrous carbon nanostructure was determined by measuring the diameter and length of 100 fibrous carbon nanostructures selected at random using a transmission electron microscope, and the ratio of the diameter to the length (long It can be obtained by calculating an average value of (thickness / diameter).
  • the BET specific surface area of the fibrous carbon nanostructure is preferably 600 m 2 / g or more, more preferably 800 m 2 / g or more, and preferably 2500 m 2 / g or less. More preferably, it is 2 / g or less. If the BET specific surface area of the fibrous carbon nanostructure containing CNT is 600 m 2 / g or more, physical properties such as conductivity of the composite can be improved. Moreover, if the BET specific surface area of the fibrous carbon nanostructure containing CNT is 2500 m 2 / g or less, excessive crowding of the fibrous carbon nanostructure is suppressed, and the fibrous carbon nanostructure and fine particles are good. Can be obtained.
  • the lithium ion secondary battery can exhibit more excellent cycle characteristics.
  • the “BET specific surface area” refers to a nitrogen adsorption specific surface area measured using the BET method.
  • the fibrous carbon nanostructure (especially the fibrous carbon nanostructure containing CNT) which has the property mentioned above, for example on the base material which has the catalyst layer for carbon nanotube manufacture on the surface, and a raw material compound and
  • a carrier gas is supplied to synthesize CNTs by chemical vapor deposition (CVD)
  • the catalytic activity of the catalyst layer is dramatically increased by the presence of a small amount of oxidant (catalyst activation material) in the system.
  • oxidant catalyst activation material
  • the carbon nanotube obtained by the super growth method may be referred to as “SGCNT”.
  • the fibrous carbon nanostructure containing CNT manufactured by the super growth method may be comprised only from SGCNT, and may be comprised from SGCNT and a non-cylindrical carbon nanostructure.
  • the fibrous carbon nanostructure containing CNT includes a single-layer or multi-layer flat cylindrical carbon nanostructure having a tape-like portion whose inner walls are close to or bonded to each other over the entire length. May be.
  • the fibrous carbon nanostructure is an aggregate (aligned assembly) oriented in a direction substantially perpendicular to the base material on the base material having a catalyst layer for carbon nanotube growth on the surface.
  • the mass density of the fibrous carbon nanostructure as the aggregate is preferably 0.002 g / cm 3 or more and 0.2 g / cm 3 or less. If the mass density is 0.2 g / cm 3 or less, the bonding between the fibrous carbon nanostructures becomes weak, so that the fibrous carbon nanostructures can be uniformly dispersed.
  • the mass density is 0.002 g / cm 3 or more, the integrity of the fibrous carbon nanostructure can be improved, and the handling can be easily performed since it can be prevented from being broken.
  • the composite of the present invention includes tin fine particles having an average particle diameter of 10 ⁇ m or less in addition to the above-described fibrous carbon nanostructure.
  • Tin fine particles serve as a negative electrode active material that absorbs and releases lithium ions when the composite of the present invention is used as a negative electrode active material layer of a negative electrode for a lithium ion secondary battery. Then, by combining tin fine particles as the negative electrode active material and the above-described fibrous carbon nanostructure in a conductive state, the composite functions well as a negative electrode active material layer, and the capacity of the lithium ion secondary battery And it can contribute to improvement of cycle characteristics.
  • the shape of the tin fine particles is not particularly limited, and examples thereof include a spherical shape, a cubic shape, a rectangular shape, a plate shape (such as a hexagonal plate shape), a column shape, and a rod shape (such as a hexagonal rod shape).
  • the average particle size of the tin fine particles is required to be 10 ⁇ m or less, preferably 5 ⁇ m or less, more preferably 100 nm or less, and further preferably 50 nm or less. If the average particle diameter of the tin fine particles exceeds 10 ⁇ m, the cycle characteristics excellent in the secondary battery cannot be exhibited.
  • the average particle diameter of the tin fine particles can be adjusted by changing the preparation method and preparation conditions of the tin fine particles. For example, if the method for producing a composite of the present invention using a plating treatment described later is used for preparing tin fine particles, tin fine particles having a small particle diameter can be easily precipitated.
  • the average particle diameter of the tin fine particles is preferably as small as possible, and the lower limit is not particularly limited, but the average particle diameter of the tin fine particles is, for example, 10 nm. This can be done.
  • the tin particles are present inside the carbon matrix composed of the fibrous carbon nanostructure, and most of the tin particles, for example, 90% or more are carbon. More preferably, it is present inside the matrix (that is, the proportion of tin fine particles present inside the carbon matrix is 90% or more).
  • the ratio of tin fine particles present inside the carbon matrix is more preferably 100%. Even if the tin fine particles existing inside the carbon matrix are repeatedly charged and discharged by the lithium ion secondary battery as compared with the tin fine particles present on the composite surface, the negative electrode active material layer on the current collector It is hard to detach from.
  • the lithium ion secondary battery can exhibit more excellent cycle characteristics.
  • the “ratio of tin fine particles present in the carbon matrix” refers to the number of tin fine particles present in the total tin fine particles and the carbon matrix by observing the cross section of the composite with, for example, FE-SEM. Can be calculated as the ratio (%) of tin fine particles present in the carbon matrix in the total tin fine particles.
  • the composite may contain components other than the above-described fibrous carbon nanostructure and tin fine particles.
  • Other components are not particularly limited.
  • known additives dispenser, binder for negative electrode
  • the ratio of other components in the composite is preferably 5% by mass or less, preferably 3% by mass or less, based on 100% by mass of the solid content (excluding residual solvent) in the composite. More preferred is 1% by mass or less.
  • the method for producing the composite of the present invention described above is not particularly limited, but the composite of the present invention is subjected to a plating treatment using a plating solution containing a tin-containing compound on a carbon film containing a fibrous carbon nanostructure. It is preferred to use a manufacturing method. According to the method for producing a composite of the present invention, it is possible to efficiently obtain a composite in which tin fine particles are present in the carbon matrix by easily depositing tin fine particles in the carbon film.
  • the carbon film is composed of an aggregate of fibrous carbon nanostructures obtained by assembling a plurality of fibrous carbon nanostructures into a film shape.
  • a method for obtaining a carbon film by assembling a plurality of fibrous carbon nanostructures into a film shape is not particularly limited, but for example, the following method: (I) A method of forming a film by removing a solvent from a dispersion containing a plurality of fibrous carbon nanostructures and a solvent. (Ii) Fibrous carbon obtained by growing in a substantially vertical direction on a substrate. A step of forming a film by allowing the aggregate of nanostructures to fall on a substrate and then compressing as necessary is mentioned. Among these, the method (i) is preferable. The carbon film obtained through the step (i) tends to have a low density, and the plating solution is likely to penetrate in the plating process.
  • the dispersion used for the preparation of the carbon film is not particularly limited, and a dispersion obtained by dispersing an aggregate of fibrous carbon nanostructures in a solvent using a known dispersion treatment method can be used.
  • a dispersion containing a fibrous carbon nanostructure and a solvent and optionally further containing an additive for dispersion such as a dispersant can be used.
  • the fibrous carbon nanostructure described above in the section “Composite” can be used.
  • the solvent for the dispersion is not particularly limited.
  • Amides polar organic solvents such as ethers, N, N-dimethylformamide and N-methylpyrrolidone, aromatic hydrocarbons such as toluene, xylene, chlorobenzene, orthodichlorobenzene and paradichlorobenzene Kind and the like. These may be used alone or in combination of two or more.
  • the additive for dispersion that is arbitrarily blended in the dispersion is not particularly limited, and examples thereof include additives generally used for preparing dispersions such as dispersants.
  • examples thereof include additives generally used for preparing dispersions such as dispersants.
  • the amount of the additive for dispersion such as is small.
  • the dispersant used for preparing the dispersion is not particularly limited as long as it can disperse the fibrous carbon nanostructure and can be dissolved in the solvent described above. Natural polymers can be used.
  • examples of the surfactant include sodium dodecylsulfonate, sodium deoxycholate, sodium cholate, sodium dodecylbenzenesulfonate, and the like.
  • examples of the synthetic polymer include polyether diol, polyester diol, polycarbonate diol, polyvinyl alcohol, partially saponified polyvinyl alcohol, acetoacetyl group-modified polyvinyl alcohol, acetal group-modified polyvinyl alcohol, butyral group-modified polyvinyl alcohol, and silanol group-modified.
  • Polyvinyl alcohol ethylene-vinyl alcohol copolymer, ethylene-vinyl alcohol-vinyl acetate copolymer resin, dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, acrylic resin, epoxy resin, modified epoxy resin, phenoxy resin, modified phenoxy system Resin, phenoxy ether resin, phenoxy ester resin, fluorine resin, melamine resin, alkyd resin, phenol resin, Polyacrylamide, polyacrylic acid, polystyrene sulfonic acid, polyethylene glycol, and polyvinylpyrrolidone.
  • examples of natural polymers include polysaccharides such as starch, pullulan, dextran, dextrin, guar gum, xanthan gum, amylose, amylopectin, alginic acid, gum arabic, carrageenan, chondroitin sulfate, hyaluronic acid, curdlan, chitin, chitosan, Examples thereof include cellulose and salts or derivatives thereof. And these dispersing agents can be used 1 type or in mixture of 2 or more types.
  • the aggregate of 1 mm or more is not visually confirmed in the dispersion liquid.
  • the fibrous carbon nanostructures in the dispersion are dispersed at a level at which the median diameter (average particle diameter) measured by a particle size distribution meter is 150 ⁇ m or less. If the fibrous carbon nanostructure is well dispersed in the dispersion, the density unevenness of the carbon film obtained by removing the solvent is suppressed. In addition, the plating solution easily penetrates uniformly into the carbon film with less density unevenness, and a complex in which tin fine particles are present inside the carbon matrix can be efficiently obtained. And if the said composite_body
  • the solid content concentration of the dispersion is preferably 0.001% by mass or more and 20% by mass or less, although it depends on the type of the fibrous carbon nanostructure.
  • the solid content concentration is less than 0.001% by mass, the amount of the carbon film obtained by removing the solvent decreases, and the production efficiency may not be sufficiently increased.
  • solid content concentration exceeds 20 mass%, while there exists a possibility that the dispersibility of the fibrous carbon nanostructure in a dispersion liquid may fall, the viscosity of a dispersion liquid will increase and fluidity
  • dispersion a commercially available dispersion obtained by dispersing an aggregate of fibrous carbon nanostructures in a solvent may be used, but the dispersion was prepared by carrying out a dispersion preparation step prior to the preparation of the carbon film. It is preferable to use a dispersion.
  • the dispersion is It is more preferable to use a dispersion obtained by subjecting a coarse dispersion obtained by adding fibrous carbon nanostructures to a solvent to a dispersion treatment in which a cavitation effect or a crushing effect is obtained.
  • a coarse dispersion obtained by adding the above-described fibrous carbon nanostructure and any additive for dispersion to the solvent described above is a dispersion capable of obtaining a cavitation effect described in detail below. It is preferable to use a dispersion obtained by subjecting to a dispersion treatment capable of obtaining a treatment or crushing effect.
  • the dispersion treatment that provides a cavitation effect is a dispersion method that uses a shock wave generated by bursting of vacuum bubbles generated in water when high energy is applied to the liquid.
  • the fibrous carbon nanostructure can be favorably dispersed.
  • dispersion treatment that provides a cavitation effect
  • dispersion treatment using ultrasonic waves dispersion treatment using a jet mill
  • dispersion treatment using high shear stirring Only one of these distributed processes may be performed, or a plurality of distributed processes may be combined. More specifically, for example, an ultrasonic homogenizer, a jet mill, and a high shear stirring device are preferably used. These devices may be conventionally known devices.
  • the coarse dispersion may be irradiated with ultrasonic waves using the ultrasonic homogenizer.
  • the irradiation time may be appropriately set depending on the amount of the fibrous carbon nanostructure and the like, for example, preferably 3 minutes or more, more preferably 30 minutes or more, and preferably 5 hours or less, more preferably 2 hours or less.
  • the output is preferably 20 W or more and 500 W or less, more preferably 100 W or more and 500 W or less, and the temperature is preferably 15 ° C. or more and 50 ° C. or less.
  • the number of treatments may be appropriately set depending on the amount of the fibrous carbon nanostructure and the like, for example, preferably 2 times or more, preferably 100 times or less, more preferably 50 times or less.
  • the pressure is preferably 20 MPa or more and 250 MPa or less
  • the temperature is preferably 15 ° C. or more and 50 ° C. or less.
  • stirring and shearing may be applied to the coarse dispersion with a high shear stirring device.
  • the operation time time during which the machine is rotating
  • the peripheral speed is preferably 5 m / second or more and 50 m / second or less
  • the temperature is preferably 15 ° C. or more and 50 ° C. or less.
  • the dispersion treatment for obtaining the above-described cavitation effect it is more preferable to perform the dispersion treatment for obtaining the above-described cavitation effect at a temperature of 50 ° C. or lower. This is because a change in concentration due to the volatilization of the solvent is suppressed.
  • the dispersion treatment that provides the crushing effect can uniformly disperse the fibrous carbon nanostructures in the solvent, as well as the fibrous carbon due to the shock wave when the bubbles disappear, compared to the dispersion treatment that provides the cavitation effect described above. This is advantageous in that damage to the nanostructure can be suppressed.
  • the fibrous carbon nanostructure can be uniformly dispersed in the solvent while suppressing the generation of bubbles.
  • the back pressure applied to the coarse dispersion may be reduced to atmospheric pressure all at once, but is preferably reduced in multiple stages.
  • a dispersion system having a disperser having the following structure may be used.
  • the disperser has a disperser orifice having an inner diameter d1, a dispersion space having an inner diameter d2, and a terminal portion having an inner diameter d3 from the inflow side to the outflow side of the coarse dispersion liquid (where d2>d3> d1)).
  • the inflowing high-pressure for example, 10 to 400 MPa, preferably 50 to 250 MPa
  • coarse dispersion passes through the disperser orifice, and becomes a high flow rate fluid with decreasing pressure.
  • the high-velocity coarse dispersion liquid flowing into the dispersion space flows at high speed in the dispersion space and receives a shearing force at that time.
  • the flow rate of the coarse dispersion decreases, and the fibrous carbon nanostructure is well dispersed.
  • a fluid having a pressure (back pressure) lower than the pressure of the inflowing coarse dispersion liquid flows out from the terminal portion as the dispersion liquid of the fibrous carbon nanostructure.
  • the back pressure of the coarse dispersion can be applied to the coarse dispersion by applying a load to the flow of the coarse dispersion.
  • a rough pressure can be obtained by disposing a multistage step-down device downstream of the disperser.
  • a desired back pressure can be applied to the dispersion. Then, by reducing the back pressure of the coarse dispersion in multiple stages using a multistage pressure reducer, bubbles are generated in the dispersion when the dispersion of the fibrous carbon nanostructure is finally released to atmospheric pressure. Can be suppressed.
  • the disperser may include a heat exchanger for cooling the coarse dispersion and a cooling liquid supply mechanism. This is because the generation of bubbles in the coarse dispersion can be further suppressed by cooling the coarse dispersion that has been heated to a high temperature by applying a shearing force with the disperser. In addition, it can suppress that a bubble generate
  • the occurrence of cavitation can be suppressed, so damage to the fibrous carbon nanostructure caused by cavitation that is sometimes a concern, especially when the bubbles disappear. Damage to the fibrous carbon nanostructure due to the shock wave can be suppressed.
  • distribution process from which a crushing effect is acquired can be implemented by controlling a dispersion
  • the method for removing the solvent from the dispersion is not particularly limited, and a known solvent removing method such as drying or filtration can be used. Among these, from the viewpoint of efficiently removing the solvent, it is preferable to use reduced-pressure drying, vacuum drying or filtration as the solvent removal method. Furthermore, from the viewpoint of removing the solvent easily and quickly, the solvent removal method is preferably filtration, and more preferably vacuum filtration. If the solvent is removed quickly and efficiently, the once-dispersed fibrous carbon nanostructures can be prevented from aggregating again, and density unevenness of the resulting carbon film can be suppressed. Here, it is not necessary to completely remove the solvent in the dispersion liquid. If the fibrous carbon nanostructure remaining after the removal of the solvent can be handled as an aggregate (carbon film), some solvent remains. There is no problem even if you do.
  • the thickness of the carbon film to be obtained is preferably 2 ⁇ m or more, more preferably 5 ⁇ m or more, further preferably 10 ⁇ m or more, preferably 200 ⁇ m or less, more preferably 100 ⁇ m or less. More preferably, it is 60 ⁇ m or less.
  • the thickness of the carbon film is 2 ⁇ m or more, the strength of the resulting composite can be ensured.
  • the thickness of the carbon film is 200 ⁇ m or less, the plating solution easily penetrates to the center of the carbon film in the thickness direction during the plating process, and efficiently obtains a composite in which fine particles are present inside the carbon matrix. be able to.
  • complex is used as a negative electrode active material layer, the cycling characteristics which were further excellent in the lithium ion secondary battery can be exhibited.
  • the density of the carbon film is preferably 0.01 g / cm 3 or more, more preferably 0.10 g / cm 3 or more, still more preferably 0.50 g / cm 3 or more, , is preferably 1.80 g / cm 3 or less, more preferably 1.50 g / cm 3 or less, further preferably 1.20 g / cm 3 or less. If the density of the carbon film is 0.01 g / cm 3 or more, the strength of the resulting composite can be ensured. On the other hand, if the density of the carbon film is 1.80 g / cm 3 or less, a composite in which the plating solution easily penetrates to the central portion in the thickness direction of the carbon film and the fine particles are present inside the carbon matrix when plating is performed.
  • the “density of the carbon film” can be determined by measuring the mass, area and thickness of the carbon film and dividing the mass of the carbon film by the volume (area ⁇ thickness).
  • Electrolytic plating treatment By subjecting the above-described carbon film to electrolytic plating treatment or electroless plating treatment, preferably electrolytic plating treatment, using a plating solution, fine particles are precipitated on the carbon film surface and / or inside the carbon film, thereby forming a composite. Can be obtained.
  • the plating solution used for the plating treatment contains a tin-containing compound in the solvent, and optionally contains additives for the plating solution (dissolution aids and nonionic surfactants, and other additives generally added to the plating solution). In addition.
  • the tin-containing compound is not particularly limited as long as it is possible to deposit tin fine particles (tin plating) on the surface of the carbon film and / or the inside of the carbon film through the plating process.
  • the tin-containing compound is not particularly limited, but tin pyrophosphate, tin phosphate, tin (II) sulfate, tin (IV) sulfate, tin (II) chloride, tin (IV) chloride, tin acetate ( II), tin (IV) acetate, and hydrates thereof. These may be used alone or in combination of two or more.
  • the concentration of the tin-containing compound in the plating solution is not particularly limited as long as tin fine particles can be precipitated, and can be adjusted as appropriate.
  • concentration of the tin-containing compound in the plating solution is not particularly limited as long as tin fine particles can be precipitated, and can be adjusted as appropriate.
  • 0.01 mol / L or more and 3.0 mol / L The following is preferable.
  • solubility aid The solubilizer is added for the purpose of ensuring the solubility of the above-described tin-containing compound in a solvent (for example, water).
  • a solubilizing agent is an ionic compound other than the above tin-containing compounds, and examples thereof include metal pyrophosphate, metal phosphate, metal sulfate, metal chloride, and metal acetate.
  • the anionic component contained in a solubilizing agent is the same as the anionic component contained in a tin containing compound.
  • the concentration of the dissolution aid in the plating solution is preferably at least twice the concentration of the tin-containing compound.
  • concentration of the solubilizing agent in a plating solution is not specifically limited, Usually, it is 100 times or less of the density
  • concentration of the dissolution aid in a plating solution is 0.04 mol / L or more and 12.0 mol / L or less, for example.
  • the plating solution preferably contains a nonionic surfactant.
  • the plating solution containing the nonionic surfactant is presumed to be because the nonionic surfactant has excellent affinity with the fibrous carbon nanostructure, but can easily penetrate into the carbon film. Therefore, if a plating solution containing a nonionic surfactant is used, a composite in which tin fine particles are present inside the carbon matrix can be obtained efficiently. And if the said composite_body
  • nonionic surfactants examples include polyether surfactants, alkylphenol surfactants, polyester surfactants, sorbitan ester ether surfactants, alkylamine surfactants, and the like.
  • polyether surfactants are preferable from the viewpoint of improving the physical properties of the composite and further improving the cycle characteristics of the lithium ion secondary battery.
  • Polyether-based surfactants include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polyoxyethylene oleyl ether, polyoxyethylene stearyl ether, polyoxyethylene lauryl ether, polyoxyethylene dodecyl ether, polyoxyethylene nonylphenyl ether , Polyoxyethylene octyl phenyl ether, and polyoxyethylene / polyoxypropylene block copolymer.
  • polyethylene glycol is particularly preferable.
  • a nonionic surfactant may be used individually by 1 type and may use 2 or more types together.
  • the weight average molecular weight of the nonionic surfactant is not particularly limited, but is preferably 500 or more, preferably 20000 or less, more preferably 10,000 or less, and still more preferably 5000 or less. It is especially preferable that it is 4000 or less. If the weight average molecular weight of the nonionic surfactant is within the above-mentioned range, the metal and the fibrous carbon nanostructure can be combined more satisfactorily, and the physical properties of the composite can be further improved. In addition, the weight average molecular weight (Mw) of a nonionic surfactant can be calculated
  • the plating solution may contain known additives for plating solutions such as brighteners in addition to the above-described tin-containing compound, solubilizing agent, and nonionic surfactant as long as the effects of the present invention are not impaired. Good.
  • the plating solution can be prepared by dissolving or dispersing the above-described components in a known solvent such as water.
  • the method for plating the carbon film is not particularly limited as long as it is a method capable of precipitating tin fine particles.
  • a carbon film may be used as the cathode, or a laminate formed by adhering a carbon film to the substrate surface via a carbon tape or the like may be used.
  • a cathode it is possible to use a cathode composed only of a carbon film from the viewpoint of facilitating the penetration of the plating solution into the carbon film and efficiently producing a composite having fine particles inside the carbon matrix. preferable.
  • the plating treatment is not limited to electrolytic plating, and electroless plating can also be employed.
  • electrolytic plating there is no limitation to direct current plating, and current reversal plating and pulse plating can also be employed.
  • the plating solution may be stirred with a stirrer, for example.
  • a waiting time from when the carbon film is immersed in the plating solution to when the plating treatment is started (for example, in the case of electrolytic plating treatment, energization is started) (wait time before plating treatment) )
  • the waiting time before the plating treatment is preferably 5 minutes or more, more preferably 10 minutes or more. If the waiting time before the plating process is 5 minutes or more, the carbon film surface is sufficiently wetted with the plating solution (the carbon film surface and the plating solution are familiar), and the plating solution penetrates into the carbon film. Can be encouraged. Further, the waiting time before the plating treatment is preferably 60 minutes or less, more preferably 30 minutes or less, considering the efficiency of the treatment.
  • the amount of energization can be adjusted as appropriate according to the size (area and thickness) of the carbon film, and by appropriately adjusting the amount of energization, tin fine particles can be suitably used inside the carbon film. It can be carried in a state.
  • the plating time is not particularly limited, but is usually 10 minutes or longer.
  • the composite of the present invention described above can be used for producing the negative electrode for a lithium ion secondary battery of the present invention.
  • the negative electrode for a lithium ion secondary battery of the present invention includes a negative electrode active material layer, and the negative electrode active material layer is the composite of the present invention. Since the negative electrode for a lithium ion secondary battery of the present invention uses the composite of the present invention as the negative electrode active material layer, the lithium ion secondary battery has a high capacity and is sufficiently superior to the lithium ion secondary battery. Cycle characteristics can be exhibited.
  • the negative electrode for a lithium ion secondary battery of the present invention is not particularly limited as long as the composite of the present invention can function as a negative electrode active material layer, and is composed only of the composite as a negative electrode active material layer.
  • a negative electrode may be sufficient and the negative electrode by which the composite_body
  • the negative electrode for a lithium ion secondary battery of the present invention is a negative electrode in which a composite as a negative electrode active material layer is disposed on a current collector, the negative electrode active material layer is disposed in contact with the current collector.
  • the negative electrode active material layer may be disposed on the current collector through another layer such as an adhesive layer.
  • an electrically conductive and electrochemically durable material is used.
  • a current collector for example, a current collector made of a metal material such as iron, copper, aluminum, nickel, stainless steel, titanium, tantalum, gold, or platinum can be used.
  • a collector of a negative electrode the thin film which consists of copper is preferable.
  • the adhesive layer arbitrarily disposed between the current collector and the negative electrode active material layer is not particularly limited as long as electrical conductivity is ensured and the current collector and the negative electrode active material layer can be bonded.
  • the adhesive layer is preferably a layer including a conductive material such as conductive carbon and a binder, for example.
  • a negative electrode for a lithium ion secondary battery in which an adhesive layer is present between a negative electrode active material layer and a current collector has an adhesive layer containing a conductive material, a binder, and a solvent on one surface of the composite.
  • the adhesive paste is applied to the surface of the composite coated with the adhesive layer paste, and the solvent in the adhesive layer paste is removed by drying or the like. it can.
  • the above-described negative electrode for a lithium ion secondary battery of the present invention is used by being incorporated in a lithium ion secondary battery.
  • the lithium ion secondary battery includes a positive electrode, a negative electrode, an electrolytic solution, and a separator, and the negative electrode is used as a negative electrode for a lithium ion secondary battery of the present invention.
  • Any known positive electrode, electrolytic solution, and separator can be used.
  • a lithium ion secondary battery including the negative electrode for a lithium ion secondary battery of the present invention has a high capacity and exhibits sufficiently excellent cycle characteristics.
  • Capacity maintenance ratio ⁇ C 90% or more
  • Capacity maintenance ratio ⁇ C 85% or more and less than 90%
  • Capacity maintenance ratio ⁇ C 80% or more and less than 85%
  • D Capacity maintenance ratio ⁇ C is 75% or more and less than 80%
  • Example 1 ⁇ Synthesis of fibrous carbon nanostructure containing single-walled CNT> A fibrous carbon nanostructure containing single-walled CNTs used in the examples was prepared by the super-growth method (hereinafter referred to as “fibrous carbon nanostructure A”) as described in International Publication No. 2006/011655.
  • the thickness of the iron catalyst thin film layer of the metal catalyst was 2 nm.
  • the obtained fibrous carbon nanostructure A had a BET specific surface area of 1050 m 2 / g (unopened state) and an average diameter (Av) of 3.3 nm.
  • the fibrous carbon nanostructure A was measured with a Raman spectrophotometer, a spectrum of a radial breathing mode (RBM) in a low wavenumber region of 100 to 300 cm ⁇ 1 characteristic for single-walled CNTs was observed.
  • the t plot in the unopened state shows an upwardly convex shape, the inflection point is in the range of 0.55 ⁇ t (nm) ⁇ 1.0, and the ratio between the total specific surface area S1 and the internal specific surface area S2. Satisfies 0.05 ⁇ S2 / S1 ⁇ 0.30.
  • the median diameter (average particle diameter) of the fibrous carbon nanostructure A in the dispersion A was 24.1 ⁇ m.
  • the obtained dispersion A was filtered under reduced pressure using Kiriyama filter paper (No. 5A) to obtain a carbon film A having a thickness of 40 ⁇ m and a density of 0.85 g / cm 3 .
  • Composite A was produced by performing electroplating under the following conditions in a tin plating bath using the carbon film A described above as a cathode and a pure tin plate as an anode.
  • the pure tin plate as an anode was disposed on both the front and back sides of the carbon film A as a cathode, one in total so as not to contact the carbon film A.
  • Electrodeposition mode Current regulation method Current density: 0.05 A / dm 2 Energization amount: 96C Waiting time before plating: 30 minutes
  • a conductive carbon paste (adhesive layer paste) containing conductive carbon as a conductive material was applied to one side of the composite A having a thickness of 40 ⁇ m obtained as described above.
  • a copper foil having a thickness of 20 ⁇ m as a current collector was placed on the coated surface, and a negative electrode A in which the composite A as a negative electrode active material layer and the copper foil as a current collector were adhered by an adhesive layer was obtained.
  • LiCoO 2 volume average particle diameter D50: 12 ⁇ m
  • the positive electrode slurry composition obtained as described above was applied on a current collector 20 ⁇ m thick aluminum foil with a comma coater so that the film thickness after drying was about 150 ⁇ m and dried. It was. This drying was performed by transporting the aluminum foil in an oven at 60 ° C. at a speed of 0.5 m / min for 2 minutes. Thereafter, heat treatment was performed at 120 ° C. for 2 minutes to obtain a positive electrode raw material. The positive electrode raw material before pressing was rolled with a roll press to obtain a positive electrode after pressing with a thickness of 80 ⁇ m.
  • a laminate was obtained by laminating the positive electrode after pressing obtained above, a separator having adhesive layers on both sides, and the negative electrode A obtained above in this order and adhering them together.
  • the obtained laminate was wound with a winding machine to obtain a wound body.
  • the wound body was pressed at 60 ° C. and 0.5 MPa to obtain a flat body.
  • a negative electrode B was obtained in the same manner as the negative electrode A, except that a tin plate was used instead of the composite A.
  • a lithium ion secondary battery was produced in the same manner as in Example 1 except that the negative electrode B was used instead of the negative electrode A. And when the cycle characteristic of the obtained lithium ion secondary battery was evaluated, it was D evaluation.
  • Example 2 A lithium ion secondary battery was produced in the same manner as in Example 1 except that the negative electrode C produced as follows was used instead of the negative electrode A. And when the cycle characteristic of the obtained lithium ion secondary battery was evaluated, it was C evaluation.
  • ⁇ Preparation of negative electrode C> In a 5 MPa pressure vessel with a stirrer, 33 parts of 1,3-butadiene, 3.5 parts of itaconic acid, 63.5 parts of styrene, 0.4 part of sodium dodecylbenzenesulfonate as an emulsifier, 150 parts of ion-exchanged water and a polymerization initiator After adding 0.5 parts of potassium persulfate as a mixture and sufficiently stirring, the mixture was heated to 50 ° C.
  • the reaction was stopped by cooling to obtain a mixture containing a particulate binder (SBR) for the negative electrode.
  • SBR particulate binder
  • a 5% aqueous sodium hydroxide solution was added to the mixture containing the particulate binder and the pH was adjusted to 8, and then the unreacted monomer was removed by heating under reduced pressure. Then, it cooled to 30 degrees C or less, and obtained the water dispersion liquid containing a desired particulate-form binder.
  • aqueous dispersion containing the particulate binder described above and ion-exchanged water are added to the obtained mixed liquid so that the final solid content concentration is 52%. Adjust and mix for an additional 10 minutes. This was defoamed under reduced pressure to obtain a negative electrode slurry composition having good fluidity.
  • the negative electrode slurry composition obtained as described above was applied on a copper foil having a thickness of 20 ⁇ m, which was a current collector, using a comma coater and dried. This drying was performed by conveying the copper foil in an oven at 60 ° C. at a speed of 0.5 m / min for 2 minutes. Then, the negative electrode C was obtained by heat-processing at 120 degreeC for 2 minute (s).
  • Example 1 using a composite containing fibrous carbon nanostructures and tin fine particles having an average particle diameter of 10 ⁇ m or less as a negative electrode active material layer, as compared with Comparative Examples 1 and 2, It can be seen that excellent cycle characteristics can be exhibited in the lithium ion secondary battery.
  • Example 1 since tin fine particles were used as the negative electrode active material, a high-capacity lithium ion secondary battery could be obtained.
  • a negative electrode for a lithium ion secondary battery capable of increasing the capacity of the lithium ion secondary battery and causing the lithium ion secondary battery to exhibit sufficiently excellent cycle characteristics. be able to.
  • the negative electrode for lithium ion secondary batteries of this invention while being able to increase capacity of a lithium ion secondary battery, the said lithium ion secondary battery can fully exhibit the cycling characteristics which were excellent.
  • the method for producing a composite of the present invention a composite capable of increasing the capacity of a lithium ion secondary battery and exhibiting sufficiently excellent cycle characteristics in the lithium ion secondary battery is efficiently produced. Can be manufactured well.

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Abstract

Le but de la présente invention est de fournir une nouvelle technique qui permet à une batterie secondaire au lithium-ion d'avoir une capacité supérieure, tout en permettant à la batterie secondaire au lithium-ion de présenter des caractéristiques de cycle suffisamment excellentes. Un corps composite selon la présente invention comprend une nanostructure de carbone fibreux et de fines particules d'étain ayant un diamètre moyen de particule de 10 µm ou moins.
PCT/JP2017/032550 2016-09-16 2017-09-08 Corps composite, électrode négative pour batteries secondaires au lithium-ion, et procédé de production de corps composite WO2018051925A1 (fr)

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004156074A (ja) * 2002-11-01 2004-06-03 Univ Shinshu めっき構造物とその製造方法
JP2013243117A (ja) * 2012-04-25 2013-12-05 Kyocera Corp 二次電池用負極およびそれを用いた二次電池
JP2014038798A (ja) * 2012-08-20 2014-02-27 Ulvac Japan Ltd リチウムイオン二次電池の負極構造体及び負極構造体の製造方法
WO2015064772A1 (fr) * 2013-10-31 2015-05-07 日本ゼオン株式会社 Nanotubes de carbone
JP2016088815A (ja) * 2014-11-06 2016-05-23 日本ゼオン株式会社 炭素ナノ構造体集合物およびその製造方法

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007018794A (ja) * 2005-07-06 2007-01-25 Bridgestone Corp 炭素材電極及びその製造方法、並びに非水電解液二次電池

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004156074A (ja) * 2002-11-01 2004-06-03 Univ Shinshu めっき構造物とその製造方法
JP2013243117A (ja) * 2012-04-25 2013-12-05 Kyocera Corp 二次電池用負極およびそれを用いた二次電池
JP2014038798A (ja) * 2012-08-20 2014-02-27 Ulvac Japan Ltd リチウムイオン二次電池の負極構造体及び負極構造体の製造方法
WO2015064772A1 (fr) * 2013-10-31 2015-05-07 日本ゼオン株式会社 Nanotubes de carbone
JP2016088815A (ja) * 2014-11-06 2016-05-23 日本ゼオン株式会社 炭素ナノ構造体集合物およびその製造方法

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