WO2017073474A1 - Électrode, condensateur utilisant ladite électrode et procédé permettant de produire une électrode - Google Patents

Électrode, condensateur utilisant ladite électrode et procédé permettant de produire une électrode Download PDF

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WO2017073474A1
WO2017073474A1 PCT/JP2016/081243 JP2016081243W WO2017073474A1 WO 2017073474 A1 WO2017073474 A1 WO 2017073474A1 JP 2016081243 W JP2016081243 W JP 2016081243W WO 2017073474 A1 WO2017073474 A1 WO 2017073474A1
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electrode
fibrous cellulose
carbon powder
cellulose
electrode according
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PCT/JP2016/081243
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English (en)
Japanese (ja)
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大輔 堀井
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日本ケミコン株式会社
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Priority to JP2017547767A priority Critical patent/JP6848877B2/ja
Priority to CN201680061945.1A priority patent/CN108352258A/zh
Publication of WO2017073474A1 publication Critical patent/WO2017073474A1/fr

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
    • H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
    • H01G11/22—Electrodes
    • H01G11/24—Electrodes characterised by structural features of the materials making up or comprised in the electrodes, e.g. form, surface area or porosity; characterised by the structural features of powders or particles used therefor
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
    • H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
    • H01G11/22—Electrodes
    • H01G11/30—Electrodes characterised by their material
    • H01G11/32—Carbon-based
    • H01G11/38—Carbon pastes or blends; Binders or additives therein
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
    • H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
    • H01G11/22—Electrodes
    • H01G11/30—Electrodes characterised by their material
    • H01G11/32—Carbon-based
    • H01G11/42—Powders or particles, e.g. composition thereof
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
    • H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
    • H01G11/84—Processes for the manufacture of hybrid or EDL capacitors, or components thereof
    • H01G11/86—Processes for the manufacture of hybrid or EDL capacitors, or components thereof specially adapted for electrodes
    • 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
    • H01M4/133—Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • 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
    • 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
    • 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
    • Y02E60/13—Energy storage using capacitors

Definitions

  • the present invention relates to an electrode using a carbon material, a capacitor using the electrode, and a method for manufacturing the electrode.
  • a capacitor such as an electric double layer capacitor is composed of a pair of electrodes, a separator existing therebetween, and a current collecting layer of each electrode.
  • a carbon material such as carbon powder is used for a typical electrode used for an electric double layer capacitor.
  • the following methods are known as methods for producing electrodes used in this electric double layer capacitor. That is, after adding and mixing a conductive material such as acetylene black and a resin such as polytetrafluoroethylene and tetrafluoroethylene resin to activated carbon powder, which is a representative electrode material, press molding. A sheet-like polarizable electrode is formed. In addition to this, there is a method (coating method) in which the mixture is contained in a solvent and applied to a current collector.
  • a resin-based binder is used when pressure molding or when a mixed solution such as activated carbon powder is applied to the current collector.
  • a mixed solution such as activated carbon powder
  • a large amount of a resin-based binder is required when a sheet-like polarizable electrode is formed by applying to a current collector.
  • an electrode using a large amount of a resin-based binder has a problem that the resistance becomes high.
  • the present invention has been proposed to solve the above problems.
  • the object is to provide an electrode with reduced electrical resistance, a capacitor using the electrode, and a method of manufacturing the electrode.
  • the electrode of the present invention includes fibrous cellulose and carbon powder, and the carbon powder is entangled and supported between fibers of the fibrous cellulose. .
  • the fibrous cellulose and the carbon powder may be deposited on a filter paper and formed into a sheet shape.
  • the fibrous cellulose may be cellulose nanofiber.
  • the carbon powder may be activated carbon black.
  • a silane coupling agent may be bonded to the surface of the fibrous cellulose.
  • the silane coupling agent may have an alkyl group as a functional group.
  • the fibrous cellulose may be contained in a proportion of 5% by weight to 40% by weight with respect to the total amount of the fibrous cellulose and the carbon powder. Moreover, you may make it contain the said fibrous cellulose in the ratio of 5 to 15 weight% with respect to the total amount of the said fibrous cellulose and the said carbon powder.
  • a capacitor in which the electrode described above is formed on a current collector is also an embodiment of the present invention.
  • an electrode with reduced electrical resistance it is possible to provide an electrode with reduced electrical resistance, a capacitor using the electrode, and a method for manufacturing the electrode.
  • Electrode and an electrode manufacturing method according to the present invention will be described in detail.
  • a capacitor to which the electrode of this embodiment is applied will be described taking a coin-shaped electric double layer capacitor as an example.
  • the electrode and the electrode manufacturing method according to the present invention are applicable not only to electric double layer capacitors.
  • it can be applied to power storage devices such as various capacitors and secondary batteries such as electrochemical capacitors including lithium ion capacitors.
  • the electrode and the electrode manufacturing method according to the present invention are not limited to the coin-type electric double layer capacitor, but may be applied to a laminate type heat sealed using a laminate film. Moreover, you may apply to the cylindrical element wound through the separator between the positive electrode and the negative electrode. Furthermore, the present invention can also be applied to power storage devices such as various capacitors and secondary batteries using a stacked element that is stacked between a positive electrode and a negative electrode via a separator.
  • FIG. 1 is a cross-sectional view of a coin type electric double layer capacitor in which a sheet electrode using carbon powder and fibrous cellulose is applied to a coin type cell as an example of an electric double layer capacitor.
  • the coin-shaped electric double layer capacitor includes a negative electrode case 1, an electrolyte 2, an electrode 3, a separator 4, an electrode 5, a positive electrode case 6, and a gasket 7.
  • the negative electrode case 1 and the positive electrode case 6 are cell casings that overlap to form a space inside.
  • the negative electrode case 1 serves as a negative electrode current collector and a negative electrode terminal.
  • the positive electrode case 6 serves as a positive electrode current collector and a positive electrode terminal.
  • the gasket 7 is interposed in the caulking between the negative electrode case 1 and the positive electrode case 6. The gasket 7 maintains electrical insulation between the negative electrode and the positive electrode, and seals and seals the cell contents.
  • Electrolyte 2, electrode 3, electrode 5, and separator 4 are cell contents and are accommodated in the space formed by negative electrode case 1 and positive electrode case 6.
  • the electrodes 3 and 5 are sheet-like electrodes using carbon powder and fibrous cellulose.
  • the sheet-like electrodes 3 and 5 are integrated with a current collector (not shown).
  • the electrode 3 is fixed and electrically connected to the positive electrode case 6 by a conductive resin adhesive, press bonding, or the like.
  • the electrode 5 is fixed and electrically connected to the negative electrode case 1 by a conductive resin adhesive, press bonding, or the like.
  • the separator 4 is disposed so as to be interposed between the electrode 3 and the electrode 5 in order to prevent a short circuit due to contact between the opposing electrode 3 and the electrode 5.
  • the electrolyte 2 is impregnated in the electrode 3, the electrode 5, and the separator 7.
  • the electrode 3 and the electrode 5 include a mixture of fibrous cellulose and carbon powder. Specifically, the carbon powder is entangled and supported between fibers of fibrous cellulose.
  • the electrode 3 and the electrode 5 are sheet-like electrodes obtained by dispersing carbon powder and fibrous cellulose in a solvent and then removing the solvent.
  • Fibrous cellulose is cellulose that can efficiently entangle extremely small nano-sized carbon powder between fibers.
  • fibrous cellulose include cellulose nanofibers.
  • the cellulose nanofiber is preferably fibrous cellulose having a width of 4 to 100 nm and a length of 50 to 1000 ⁇ m.
  • a silane coupling agent may be bonded to the surface of the fibrous cellulose.
  • a silane coupling agent having a methacryl group and an alkyl group as functional groups can be used.
  • Bonding of the silane coupling agent to fibrous cellulose can be performed by the following procedure. For example, after adding fibrous cellulose and a silane coupling agent to isopropyl alcohol at a mass ratio of 100: 1, the resulting liquid is stirred using a homogenizer. Next, by drying the stirred solution, fibrous cellulose having a silane coupling agent bonded to the surface can be obtained.
  • Carbon powder expresses the main capacity of the electrode.
  • the types of carbon powder include natural plant tissues such as palm, synthetic resins such as phenol, activated carbon derived from fossil fuels such as coal, coke, and pitch, ketjen black, acetylene black, channel black, etc. And carbon black, carbon nanohorn, amorphous carbon, natural graphite, artificial graphite, graphitized ketjen black, activated carbon, mesoporous carbon, and the like.
  • the carbon powder is preferably used after being subjected to a porous treatment such as activation treatment or opening treatment.
  • the carbon powder activation method varies depending on the raw material used, but conventionally known activation treatments such as a gas activation method and a drug activation method can be usually used.
  • the gas used in the gas activation method include water vapor, air, carbon monoxide, carbon dioxide, hydrogen chloride, oxygen, or a gas composed of a mixture thereof.
  • alkali metal hydroxide such as sodium hydroxide and potassium hydroxide
  • alkaline earth metal hydroxide such as calcium hydroxide
  • boric acid phosphoric acid
  • sulfuric acid hydrochloric acid
  • Inorganic acids such as zinc chloride
  • inorganic salts such as zinc chloride.
  • the carbon powder preferably has a specific surface area in the range of 600 to 2000 m 2 / g.
  • the carbon powder preferably has an average primary particle size of less than 100 nm, and particularly preferably less than 50 nm. If the average particle size of the carbon powder is less than 100 nm, the diffusion resistance is low and the conductivity is high because of the extremely small particle size. Moreover, since the specific surface area by the porous treatment is large, an effect of expressing a high capacity can be expected. If the average particle diameter of the carbon powder is larger than 100 nm, the ion diffusion resistance in the carbon powder particles increases, and the resistance of the resulting capacitor increases.
  • the average particle size is preferably 5 nm or more.
  • the improvement of electrical conductivity is obtained by taking the form which connected the very small carbon powder which made the average particle diameter less than 100 nm individually (in a daisy chain form).
  • the carbon powder activated carbon black is particularly preferable.
  • the effects of the present invention can be achieved by the ultracentrifugation process and the jet mixing process described later as the dispersion method.
  • the electrode of the present embodiment includes a mixture of carbon powder and fibrous cellulose as described above.
  • the content is 5 to 40% by weight, especially 5 to 15% by weight, based on the total amount of carbon powder and fibrous cellulose. Is preferred.
  • the range of high capacity density and low internal resistance is maintained, but when the content of fibrous cellulose increases to 50% by weight, the internal resistance of the capacitor is in the range of low internal resistance. And the capacity density tends to decrease outside the range of the high capacity density. On the other hand, if it is smaller than this range, the carbon powder tends to be aggregated, making it difficult to form the electrode 3 and the electrode 5 in a sheet form. Furthermore, the range of 5% by weight to 15% by weight of the fibrous cellulose achieves outstanding high capacity density and low internal resistance even within the range of 5% by weight to 40% by weight of the fibrous cellulose. preferable.
  • Solvents for dispersing carbon powder and fibrous cellulose include alcohols such as methanol, ethanol and 2-propanol, hydrocarbon solvents, aromatic solvents, N-methyl-2-pyrrolidone (NMP) and N, N-.
  • Various solvents such as an amide solvent such as dimethylformamide (DMF), water, a solvent using these solvents alone or a mixture of two or more solvents can be used.
  • additives such as a dispersing agent, in this solvent.
  • a conductive material such as aluminum foil, platinum, gold, nickel, titanium, steel, and carbon can be used.
  • shape of the current collector any shape such as a film shape, a foil shape, a plate shape, a net shape, an expanded metal shape, and a cylindrical shape can be adopted.
  • the surface of the current collector may be formed with an uneven surface by etching or the like, or may be a plain surface.
  • Negative electrode case positive electrode case
  • the negative electrode case 1 is formed by drawing a stainless steel plate whose outer surface is plated with Ni. Further, the positive electrode case 6 is made of stainless steel plated with Ni on the outer side surface serving as the cell case main body or a valve action metal such as Al or Ti.
  • Mo-containing stainless steels such as SUS316, 316L and double-layered stainless steel, and valve metals such as Al and Ti have high corrosion resistance and can be suitably used. Further, it is particularly preferable to use a clad material in which stainless steel and a valve metal such as Ai or Ti are bonded by crimping by cold rolling or the like, with the valve metal side being the inner surface of the cell. This is because a cell having high corrosion resistance against high voltage application, high mechanical strength at the time of sealing, and high reliability of sealing can be obtained.
  • the negative electrode case 1 and the positive electrode case 6 may be made of the materials described as the above-described current collector, or may be applied in the form.
  • the separator 4 can be a cellulose separator, a synthetic fiber nonwoven fabric separator, a mixed paper separator made by mixing cellulose and synthetic fibers, or the like.
  • Polyester, polyphenylene sulfide, polyethylene terephthalate, polybutylene terephthalate, polyamide, polyimide, fluororesin, polyolefin resins such as polypropylene and polyethylene, non-woven fabrics made of fibers such as ceramics and glass, mixed paper or porous films are preferably used. Can do. When performing reflow soldering, a resin having a heat distortion temperature of 230 ° C. or higher is used.
  • polyphenylene sulfide polyethylene terephthalate, polyamide, fluororesin, ceramics, glass, or the like can be used.
  • an acid-resistant material synthetic fiber nonwoven fabric or glass material.
  • Electrolyte Electrolyte 2 is a chain sulfone such as ethylene carbonate, propylene carbonate, vinylene carbonate, butylene carbonate, dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, ethyl isopropyl sulfone, ethyl methyl sulfone, ethyl isobutyl sulfone, sulfolane, 3 -Methyl sulfolane, ⁇ -butyrolactone, acetonitrile, 1,2-dimethoxyethane, N-methylpyrrolidone, dimethylformamide, dimethyl sulfoxide, tetrahydrofuran, 2-methyltetrahydrofuran, 1,3-dioxolane, nitromethane, ethylene glycol, ethylene glycol dimethyl ether, Solvents such as ethylene glycol diethyl ether, water or mixtures thereof can be used.
  • the electrolyte 2 is a mixture of sulfolane and a sulfolane compound having a side chain in the sulfolane skeleton or a chain sulfone
  • the sulfolane compound has a cyclic sulfone structure of tetrahydrothiophene-1,1-dioxide, and is, for example, a compound having a side chain of an alkyl group on a sulfolane skeleton such as sulfolane and 3-methylsulfolane, or a mixture thereof.
  • the chain sulfone has a chain structure in which two alkyl groups are bonded to a sulfonyl group, and examples thereof include ethyl isopropyl sulfone, ethyl methyl sulfone, and ethyl isobutyl sulfone.
  • the electrolyte 2 contains one or more electrolytes selected from the group consisting of quaternary ammonium salts or lithium salts. Any quaternary ammonium salt or lithium salt can be used as long as the electrolyte can generate quaternary ammonium ions and lithium ions. It is more preferable to use one or more selected from the group consisting of quaternary ammonium salts and lithium salts.
  • ethyltrimethylammonium BF 4 diethyldimethylammonium BF 4 , triethylmethylammonium BF 4 , tetraethylammonium BF 4 , spiro- (N, N ′)-bipyrrolidinium BF 4 , methylethylpyrrolidinium BF 4 , 1-ethyl- 3-methylimidazolium BF 4 , 1-ethyl-2,3-dimethylimidazolium BF 4 , ethyltrimethylammonium PF 6 , diethyldimethylammonium PF 6 , triethylmethylammonium PF 6 , tetraethylammonium PF 6 , spiro- (N, N ') - bipyrrolidinium PF 6, tetramethyl ammonium bis (oxalato) borate, trimethyl ammonium bis (ox)
  • the electrolyte may contain various additives.
  • additives include phosphoric acids and derivatives thereof (phosphoric acid, phosphorous acid, phosphoric esters, phosphonic acids, etc.), boric acids and derivatives thereof (boric acid, boric oxide, boric esters, boron and hydroxyl groups, And / or a complex with a compound having a carboxyl group), a nitrate (such as lithium nitrate), a nitro compound (such as nitrobenzoic acid, nitrophenol, nitrophenetole, nitroacetophenone, and an aromatic nitro compound).
  • the amount of the additive is preferably 10% by weight or less, more preferably 5% by weight or less of the total electrolyte from the viewpoint of conductivity.
  • the electrolyte may contain a gas absorbent.
  • the absorbent for the gas generated from the electrode is not particularly limited as long as it does not react with each component of the electrolyte (solvent, electrolyte salt, various additives, etc.) and does not remove (adsorb). Specific examples include zeolite and silica gel.
  • the gasket 7 is mainly composed of a resin that is insoluble in the electrolyte 2 and has an electrical insulation property.
  • the gasket 7 is usually made of a resin such as polypropylene or nylon.
  • a resin having a heat distortion temperature of 230 ° C. or higher is used.
  • polyphenylene sulfide, polyethylene terephthalate, polyamide, liquid crystal polymer (LCP), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin (PFA), polyether ether ketone resin (PEEK), polyether nitrile resin (PEN), Polyetherketone resin (PEK), polyarylate resin, polybutylene terephthalate resin, polycyclohexanedimethylene terephthalate resin, polyethersulfone resin, polyaminobismaleimide resin, polyetherimide resin, fluorine resin, and the like can be used.
  • a material obtained by adding glass fibers, My Cowisker, ceramic fine powder and the like to these materials in an addition amount of about 30% by weight or less can be suitably used.
  • Electrode manufacturing method The manufacturing method of the electrode of this embodiment as described above includes the following steps. (1) Dispersing step of dispersing carbon powder and fibrous cellulose in a solvent (2) Removing the solvent of the solution obtained in the dispersing step to obtain an electrode of carbon powder and fibrous cellulose
  • Dispersing step carbon powder and fibrous cellulose are dispersed in a solvent. That is, in the dispersion step, a dispersion treatment is performed on a mixed solution obtained by mixing carbon powder and fibrous cellulose. By performing the dispersion treatment, the carbon powder and the fibrous cellulose in the mixed solution are subdivided and homogenized, and dispersed in the solution. That is, the fibrous cellulose in the mixed solution before the dispersion treatment is in a state where the cellulose fibers are entangled (bundle shape). By performing the dispersion treatment, the bundle of fibrous cellulose is broken and the fibrous cellulose is dispersed in the solution.
  • the dispersion method As a dispersion method, a mixer, jet mixing (jet collision), ultracentrifugation, or other ultrasonic treatment is used. Considering the improvement in the degree of dispersion of the carbon powder and the fibrous cellulose in the solvent and the improvement in the electrode density of the obtained sheet electrode, the dispersion method is preferably jet mixing or ultracentrifugation. In particular, by using such jet mixing or ultracentrifugation treatment, aggregation of carbon powder having a very small particle diameter and fibrous cellulose is suppressed, and an electrode having a low internal resistance can be obtained.
  • a physical force is applied to a mixed solution containing carbon powder and fibrous cellulose by a ball mill, a homogenizer, a homomixer, or the like, and the carbon powder and fibrous cellulose in the solution are stirred. Subdivide.
  • the agglomerated carbon powder and fibrous cellulose can be subdivided and homogenized, and the entangled carbon powder and fibrous cellulose can be solved.
  • a pair of nozzles are provided at positions facing each other on the inner wall of the cylindrical chamber.
  • a mixed solution containing carbon powder and fibrous cellulose is pressurized by a high-pressure pump and sprayed from a pair of nozzles to cause a frontal collision in the chamber.
  • the bundle of fibrous cellulose is pulverized, and can be dispersed and homogenized.
  • the pressure is preferably 100 MPa or more and the concentration is less than 5 g / l.
  • ultracentrifugation is performed on a mixed solution containing carbon powder and fibrous cellulose.
  • shear stress and centrifugal force are applied to the carbon powder and fibrous cellulose in the mixed solution in a rotating container.
  • the mixed solution is introduced into the inner cylinder of the container, and the inner cylinder is swirled so that the centrifugal force causes carbon powder and fibrous cellulose inside the inner cylinder to pass through the through hole of the inner cylinder. It collides with the inner wall of the cylinder, forms a thin film, and slides up to the upper part of the inner wall.
  • the centrifugal force applied to the carbon powder and the fibrous cellulose in the inner cylinder necessary for the present invention is 1500 N (kgms -2) or more, preferably 60000N (kgms -2) or more, more preferably 270000N (kgms -2) That's it.
  • the dispersion treatment as described above is preferably performed on a mixed solution obtained by mixing carbon powder and fibrous cellulose.
  • a solution in which fibrous cellulose is added separately is prepared, a dispersion treatment is performed on this solution to obtain a fibrous cellulose in which the bundle is unwound, and a mixed solution is obtained by mixing the fibrous cellulose and carbon powder. May be.
  • a solution in which carbon powder is separately added is prepared, and a dispersion treatment is performed on the solution to obtain a finely divided carbon powder.
  • the carbon powder and fibrous cellulose may be mixed to obtain a mixed solution. .
  • a solution in which fibrous cellulose is added separately is prepared, and a dispersion treatment is performed on this solution to obtain a fibrous cellulose in which the bundle is unwound.
  • a solution in which carbon powder is additionally added is prepared.
  • dispersion treatment may be performed to obtain a finely divided carbon powder, and these fibrous cellulose and carbon powder may be mixed to obtain a mixed solution. These mixed solutions may be subjected to dispersion treatment.
  • sheet-like electrodes 3 and 5 made of carbon powder and fibrous cellulose are obtained by papermaking.
  • the solvent of the mixed solution that has passed through the dispersing step is removed by filtering the mixed solution that has passed through the dispersing step.
  • filter paper such as glass fiber nonwoven fabric, organic nonwoven fabric (polytetrafluoroethylene, polyethylene, etc.) or metal fiber nonwoven fabric can be used.
  • the solvent in the mixed solution is removed by filtering and drying the mixed solution under reduced pressure using a filter paper. Therefore, carbon powder and fibrous cellulose are deposited on the filter paper, and the sheet electrode 3 and the electrode 5 are obtained.
  • the carbon powder is dispersed and supported between the fiber celluloses.
  • the sheet-like electrode 3 and the electrode 5 are preferably used by being peeled from the filter paper.
  • the carbon powder and fibrous cellulose sheet-like electrode 3 and electrode 5 produced in this sheet electrode forming step are cut to the same size as the current collector.
  • the cut sheet-like electrode 3 and electrode 5 are placed on an etched aluminum foil to be a current collector, and are pressed from above and below the foil and the sheet electrode to bite into the uneven surface of the aluminum foil.
  • the aforementioned press may be used, or a conductive adhesive may be used.
  • the electrode 5 and the electrode 7 may be subjected to a flattening process by pressing or the like before being integrated with the current collector, if necessary.
  • the effect which the electrode of this embodiment shows is as follows.
  • the electrode of this embodiment includes fibrous cellulose and carbon powder, and the carbon powder is entangled and supported between fibers of fibrous cellulose.
  • fibrous cellulose plays a role as a binder and can hold the carbon powder in a small amount, so that an electrode with reduced resistance can be provided.
  • Fibrous cellulose and carbon powder are deposited on the filter paper to form a sheet.
  • the resistance can be reduced by preparing a sheet-like electrode on the filter paper by filtering the mixed solution without using a resin binder.
  • Fibrous cellulose is cellulose nanofiber.
  • the carbon powder can be surely entangled between the fibers of the cellulose nanofiber. Therefore, an increase in internal resistance can be suppressed.
  • the carbon powder is activated carbon black. Since the carbon black made porous by the activation treatment has a large specific surface area, a high capacity expression effect can be expected. Carbon black is dispersed and supported in a network of fibrous cellulose as small aggregates. Therefore, the dispersion degree of carbon black in fibrous cellulose can be improved. Therefore, an increase in internal resistance can be suppressed.
  • a silane coupling agent is bonded to the surface of the fibrous cellulose.
  • Fibrous cellulose has OH groups on the surface. Therefore, for example, when fibrous cellulose is used in a non-aqueous electric double layer capacitor, hydrolysis may occur due to water caused by OH groups, which may cause deterioration of the capacitor.
  • the silane coupling agent is bonded to the surface of the fibrous cellulose, the functional group of the silane coupling agent is oriented on the surface. Since the functional group of the silane coupling agent is hydrophobic, deterioration due to the OH group of the fibrous cellulose can be prevented.
  • the silane coupling agent has an alkyl group as a functional group.
  • a silane coupling agent having an alkyl group is used, the initial equivalent series resistance can be reduced and the capacity retention rate after the load test can be improved.
  • the equivalent series resistance can be reduced.
  • the manufacturing method of the electrode of this embodiment includes carbon powder and a dispersion step of dispersing fibrous cellulose in a solvent, and removing the solvent of the solution obtained in the dispersion step, so that the carbon powder and fibrous cellulose are removed.
  • Carbon fiber and fibrous cellulose are dispersed in a mixed solution, and an electrode is prepared by removing the solvent of the solution, so that fibrous cellulose plays a role as a binder. Therefore, since a resin-based binder that increases resistance is not necessary, the resistance of the electrode can be reduced. Further, by using a dispersion method such as jet mixing or ultracentrifugation, the degree of dispersion in the mixed solution of carbon powder and fibrous cellulose is improved, so that the sheet electrode is made into a dense and homogeneous form and the electrode density is increased. Therefore, an excellent sheet electrode capable of obtaining the same level of capacity as that of an electrode using conventional micron-sized carbon powder is realized.
  • a dispersion method such as jet mixing or ultracentrifugation
  • the above mixed solution was subjected to a dispersion treatment at a peripheral speed of 40 m / s for 30 seconds to prepare a carbon powder / fibrous cellulose / methanol dispersion.
  • This dispersion was filtered under reduced pressure using PTFE filter paper (diameter: 80 mm, average pore 0.2 ⁇ m) to obtain a paper electrode and a carbon powder / fibrous cellulose sheet electrode.
  • PTFE filter paper diameter: 80 mm, average pore 0.2 ⁇ m
  • the carbon powder and fibrous cellulose sheet electrodes were peeled from the aluminum plate and cut into the same size as the current collector.
  • the cut sheet electrode was attached to an aluminum foil serving as a current collector with a conductive adhesive and dried at 120 ° C. for 1 hour under normal pressure to obtain two electrode bodies.
  • the obtained two electrode bodies were arranged via a cellulose separator to produce an electric double layer capacitor element (electrode area: 2.1 cm 2 ).
  • the element was heat sealed using a laminate film and evaluated.
  • Cell electrical double layer capacitor
  • Example 2 ⁇ Preparation of Electric Double Layer Capacitor of Example 2>
  • the carbon powder was prepared in the same manner as in Example 1 except that activated carbon having an average particle diameter of several ⁇ m was used.
  • FIG. 2 shows an SEM ( ⁇ 10.0 k) image of the sheet electrode of carbon black and cellulose nanofiber obtained in Example 1.
  • the carbon black is supported so as to be entangled between the fibers of cellulose nanofibers.
  • the bundle of cellulose nanofibers is sufficiently unwound and the network of cellulose nanofibers is dense.
  • the aggregate state of carbon black collapses and is subdivided into small aggregates.
  • the dense mesh-like cellulose nanofibers are supported in the form of agglomerated carbon black, and the cellulose nanofibers and carbon black are uniformly dispersed. Therefore, the surface shape of the sheet electrode is dense.
  • the results of the calculation of the capacitance and the measurement of the initial DC resistance are shown below as the initial characteristic evaluation.
  • FIG. 3 is a graph showing the relationship between the charging voltage and the capacity density in Examples 1 and 2 and Comparative Example 1.
  • FIG. 3 shows the result of measuring two samples for each example. From this graph, it was found that the capacity density of Examples 1 and 2 was not significantly different from the capacity density of Comparative Example 1 in the range of the charging voltage from 2.7 V to 3.3 V. That is, in the electric double layer capacitor containing fibrous cellulose and carbon powder of Examples 1 and 2, an electric double layer capacitor having a high capacitance per electrode unit volume can be obtained as in the conventional case.
  • FIG. 4 is a graph showing the relationship between the charging voltage and DC resistance (DCIR) in Examples 1 and 2 and Comparative Example 1. The results measured after voltage application for 30 minutes at 2.7 V, 3 V, and 3.3 V, respectively, are shown. FIG. 4 shows the results of measuring two samples for each example. From this graph, it was found that the DC resistance of Comparative Example 1 using a resin binder that acts as an impurity was high in the range of a charging voltage of 2.7 V to 3.3 V. On the other hand, in Examples 1 and 2 in which a mixed solution in which carbon powder and fibrous cellulose are dispersed is filtered, the carbon powder is entangled and supported between fibers of fibrous cellulose. That is, since the fibrous cellulose plays a role as a binder, the direct current resistance is an extremely excellent value as compared with Comparative Example 1 using a resin binder.
  • the evaluation cell was subjected to a 3.3V constant voltage load test at 60 degrees as an acceleration test, and the results of measuring the capacity retention rate and direct current resistance (DCIR) at an arbitrary time are shown below.
  • FIG. 5 is a graph showing the relationship between the load time and the capacity maintenance rate in Examples 1 and 2 and Comparative Example 1.
  • the capacity retention ratio was determined by measuring the electrode capacity after voltage application at 3.3 V for 30 minutes and the electrode capacity after voltage application at each measurement time, and the ratio of the capacity (capacity after voltage application at each measurement time). / Capacity after voltage application for 30 minutes) ⁇ 100%.
  • the capacity maintenance rate after 500 hours is extremely lowered.
  • Examples 1 and 2 in which the mixed solution in which the carbon powder and the fibrous cellulose were dispersed was filtered, a decrease in the capacity retention rate was suppressed as compared with Comparative Example 1.
  • FIG. 6 is a graph showing the relationship between load time and DC resistance (DCIR) in Examples 1 and 2 and Comparative Example 1.
  • DCIR DC resistance
  • Example 1 and 2 which filtered the mixed solution which disperse
  • the above mixed solution was subjected to a dispersion treatment at a peripheral speed of 40 m / s for 30 seconds to prepare a fibrous cellulose / methanol dispersion.
  • the dispersion was filtered under reduced pressure using PTFE filter paper (diameter: 80 mm, average pore 0.2 ⁇ m) to obtain a sheet electrode of fibrous cellulose formed by papermaking.
  • PTFE filter paper diameter: 80 mm, average pore 0.2 ⁇ m
  • the carbon powder and fibrous cellulose sheet electrodes were peeled from the aluminum plate and cut into the same size as the current collector.
  • the cut sheet electrode was attached to an aluminum foil serving as a current collector with a conductive adhesive and dried at 120 ° C. for 1 hour under normal pressure to obtain two electrode bodies.
  • the obtained two electrode bodies were arranged via a cellulose separator to produce an electric double layer capacitor element (electrode area: 2.1 cm 2 ).
  • the element was heat sealed using a laminate film and evaluated.
  • Cell electrical double layer capacitor
  • Example 4 Preparation of Electric Double Layer Capacitor of Example 4> A silane coupling agent was prepared in the same manner as in Example 3 except that a silane coupling agent having an alkyl group as a functional group was used.
  • Example 4 using the silane coupling agent which has an alkyl group in a functional group, compared with the comparative example 2 which does not use a silane coupling agent, a capacity density is high and direct current
  • Example 3 using a silane coupling agent having a methacrylic group as a functional group the capacity density is lower and the direct current resistance is higher than in Comparative Example 2 where no silane coupling agent is used. I understood.
  • FIG. 7 is a graph showing the relationship between the load time and the capacity retention rate in Examples 3 to 4 and Comparative Example 2.
  • Example 3 using a silane coupling agent having a methacryl group as a functional group was inferior to Comparative Example 2 in terms of initial characteristics.
  • Example 3 had a higher capacity retention rate than Example 4 and Comparative Example 2.
  • Example 4 which had good initial characteristics, was able to obtain a good capacity retention rate as compared with Comparative Example 2.
  • the silane coupling agent having an alkyl group as a functional group can provide good results in both initial characteristics and capacity retention.
  • the ratio of fibrous cellulose is 9 wt%, 10 wt%, 15 wt%, 20 wt%, 30 wt%, 40 wt% and 50 wt% with respect to 50 mg of the total amount of carbon powder and fibrous cellulose.
  • each of carbon powder and fibrous cellulose was weighed and mixed with 50 ml of methanol to prepare a total of seven types of mixed solutions having different fibrous cellulose contents.
  • the carbon powder is carbon black having an average particle diameter of 12 nm subjected to steam activation treatment, and the fibrous cellulose is cellulose nanofiber having an outer diameter of 20 nm and a length of 150 ⁇ m.
  • Each sheet electrode of this carbon powder and fibrous cellulose was peeled from the aluminum plate, and cut into the same size as the current collector.
  • Each of the cut sheet electrodes was attached to an aluminum foil serving as a current collector with a conductive adhesive and dried at 120 ° C. for 1 hour under normal pressure to obtain two electrode bodies.
  • the obtained two electrode bodies were arranged via a cellulose separator to produce each electric double layer capacitor element (electrode area: 2.1 cm 2 ).
  • FIG. 8 shows that the content of fibrous cellulose is 9 wt%, 10 wt%, 15 wt%, 20 wt%, 30 wt%, 40 wt% and the total amount of carbon powder and fibrous cellulose. It is a graph which shows an electrostatic capacity density about each cell for evaluation produced with the electrode body made into 50 wt%, A horizontal axis is a content rate (%) of fibrous cellulose with respect to the total amount of carbon powder and fibrous cellulose. The vertical axis indicates the capacitance density (F / cc). Upon measurement of the capacitance density, the voltage range and 3-0V, a constant current density of 2 mA / cm 2, it was charged and discharged each evaluation cell.
  • FIG. 9 shows 9 wt%, 10 wt%, 15 wt%, 20 wt%, 30 wt%, 40 wt% and 50 wt% of the content of fibrous cellulose with respect to the total amount of carbon powder and fibrous cellulose.
  • each evaluation cell was charged and discharged with a voltage range of 3-0 V and a constant current density of 2 mA / cm 2 .
  • an internal resistance value of 5 ⁇ ⁇ cm 2 or less was achieved in the range up to 40% by weight of fibrous cellulose, but when the content of fibrous cellulose increased to 50% by weight, 6 weak ⁇ of ⁇ cm 2 rose to the internal resistance value. That is, it was confirmed that low internal resistance was achieved when the content of fibrous cellulose was in the range of up to 40% by weight. Furthermore, an internal resistance value of less than 4 ⁇ ⁇ cm 2 was achieved when the fibrous cellulose content was in the range of 5-15 wt%. That is, it was confirmed that an outstanding high capacity density was achieved when the fibrous cellulose content was in the range of 5 to 15% by weight.

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  • Engineering & Computer Science (AREA)
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  • Chemical & Material Sciences (AREA)
  • Materials Engineering (AREA)
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  • Manufacturing & Machinery (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Electric Double-Layer Capacitors Or The Like (AREA)

Abstract

La présente invention concerne : une électrode dont la résistance électrique est réduite; un condensateur électrique à double couche qui utilise cette électrode; et un procédé permettant de produire une électrode. Cette électrode contient une cellulose fibreuse et une poudre de carbone; et la poudre de carbone est emmêlée parmi les fibres de la cellulose fibreuse et supportée par ces dernières. La cellulose fibreuse et la poudre de carbone sont déposées sur un morceau de papier-filtre et formées en feuille. L'invention concerne également un procédé permettant de produire une électrode selon la présente invention, ledit procédé comprenant : une étape de dispersion au cours de laquelle une poudre de carbone et une cellulose fibreuse sont dispersées dans un solvant; et une étape de formation d'électrode en feuille au cours de laquelle le solvant dans la solution obtenue au cours de l'étape de dispersion est éliminé, ce qui permet d'obtenir une électrode en feuille de la poudre de carbone et de la cellulose fibreuse.
PCT/JP2016/081243 2015-10-27 2016-10-21 Électrode, condensateur utilisant ladite électrode et procédé permettant de produire une électrode WO2017073474A1 (fr)

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JPH10214755A (ja) * 1997-01-31 1998-08-11 Kyocera Corp 固形状活性炭及びその製造方法及びこれを用いた電気二重層コンデンサ−
JP2008098494A (ja) * 2006-10-13 2008-04-24 Matsushita Electric Ind Co Ltd アルミ電解コンデンサ
JP2008211063A (ja) * 2007-02-27 2008-09-11 Sanyo Electric Co Ltd 固体電解コンデンサ及びその製造方法
WO2013042720A1 (fr) * 2011-09-20 2013-03-28 日産化学工業株式会社 Composition de bouillie pour utilisation dans la formation d'électrode de batterie secondaire au lithium-ion, contenant une fibre de cellulose en tant que liant, et électrode de batterie secondaire au lithium-ion
JP2015005721A (ja) * 2013-02-20 2015-01-08 日本ケミコン株式会社 電極、その電極を用いた電気二重層キャパシタ、及び電極の製造方法

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US20060188784A1 (en) * 2003-07-28 2006-08-24 Akinori Sudoh High density electrode and battery using the electrode
CN104477878B (zh) * 2014-12-04 2017-01-25 中国科学院山西煤炭化学研究所 一种石墨烯基多级孔炭材料及制法和应用

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH10214755A (ja) * 1997-01-31 1998-08-11 Kyocera Corp 固形状活性炭及びその製造方法及びこれを用いた電気二重層コンデンサ−
JP2008098494A (ja) * 2006-10-13 2008-04-24 Matsushita Electric Ind Co Ltd アルミ電解コンデンサ
JP2008211063A (ja) * 2007-02-27 2008-09-11 Sanyo Electric Co Ltd 固体電解コンデンサ及びその製造方法
WO2013042720A1 (fr) * 2011-09-20 2013-03-28 日産化学工業株式会社 Composition de bouillie pour utilisation dans la formation d'électrode de batterie secondaire au lithium-ion, contenant une fibre de cellulose en tant que liant, et électrode de batterie secondaire au lithium-ion
JP2015005721A (ja) * 2013-02-20 2015-01-08 日本ケミコン株式会社 電極、その電極を用いた電気二重層キャパシタ、及び電極の製造方法

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