WO2010053200A1 - Positive electrode for secondary battery, secondary battery using same, collector, and battery using the collector - Google Patents

Positive electrode for secondary battery, secondary battery using same, collector, and battery using the collector Download PDF

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Publication number
WO2010053200A1
WO2010053200A1 PCT/JP2009/069141 JP2009069141W WO2010053200A1 WO 2010053200 A1 WO2010053200 A1 WO 2010053200A1 JP 2009069141 W JP2009069141 W JP 2009069141W WO 2010053200 A1 WO2010053200 A1 WO 2010053200A1
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compound
positive electrode
potential
carbon
current collector
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PCT/JP2009/069141
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French (fr)
Japanese (ja)
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昌俊 長濱
規史 長谷川
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株式会社エクォス・リサーチ
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Priority to CN200980138682.XA priority Critical patent/CN102171869B/en
Publication of WO2010053200A1 publication Critical patent/WO2010053200A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/624—Electric conductive fillers
    • H01M4/625—Carbon or graphite
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES OR LIGHT-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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES OR LIGHT-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 OR LIGHT-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
    • H01G11/50—Electrodes characterised by their material specially adapted for lithium-ion capacitors, e.g. for lithium-doping or for intercalation
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES OR LIGHT-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
    • H01G11/74—Terminals, e.g. extensions of current collectors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H01M10/0566—Liquid materials
    • H01M10/0569—Liquid materials characterised by the solvents
    • 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
    • H01M4/136—Electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
    • H01M4/5825—Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines
    • 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
    • H01M4/64—Carriers or collectors
    • H01M4/66—Selection of materials
    • H01M4/661—Metal or alloys, e.g. alloy coatings
    • 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
    • H01M4/64—Carriers or collectors
    • H01M4/66—Selection of materials
    • H01M4/665—Composites
    • H01M4/667—Composites in the form of layers, e.g. coatings
    • 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
    • H01M2004/021—Physical characteristics, e.g. porosity, surface area
    • 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 first invention relates to a positive electrode and a secondary battery for a secondary battery, a secondary utilizing Li 2 NiPO 4 F, LiNiPO 4 , LiCoPO 4, Li 2 CoPO 4 F or the like, a positive electrode active material charging reaction at a high potential is performed following It can be suitably used as a battery.
  • the second invention relates to a positive electrode and a secondary battery for a secondary battery, using a positive electrode active material Li 2 NiPO 4 F, LiNiPO 4 , LiCoPO 4, Li 2 CoPO 4 F or the like, the charging reaction at a high potential is performed It can be suitably used as a secondary battery.
  • the third invention relates to a current collector and a battery excellent in corrosion resistance that can be used for a lithium ion battery, a sodium ion battery, an electric double layer capacitor, a lithium ion capacitor, and the like.
  • carbon powder is mixed with a positive electrode active material of a secondary battery to impart necessary electron conductivity to the positive electrode.
  • a positive electrode active material of a secondary battery For example, lithium cobaltate (LiCoO 2 ), lithium nickelate (LiNiO 2 ), solid solutions thereof, lithium manganate (LiMn 2 O 4 ), and the like are used as positive electrode active materials for lithium ion batteries.
  • Carbon as a conductive additive is mixed with the material to provide the necessary electronic conductivity for the positive electrode, and a fluororesin such as polytetrafluoroethylene (PTFE) or polyvinylidene fluoride (PVdF) is used as a binder.
  • PTFE polytetrafluoroethylene
  • PVdF polyvinylidene fluoride
  • the raw material is carbonized when manufacturing the electrode, or the electrode active material, the conductive additive and the solvent are mixed and pulverized by a wet method, and then the solvent is removed.
  • Patent Document 1 and improving the electronic conductivity.
  • covered the surface with the metal is used as a conductive support agent (patent document 2), or a metal particle is included in the active material layer as a conductive assistant agent (patent document 3). Improvements have also been proposed.
  • a conductive current collector is used in contact with the electrode in order to take in and out electrons from an electrochemical cell such as a battery and the outside.
  • an electrochemical cell such as a battery and the outside.
  • a current collector made of aluminum is used as a current collector in contact with a positive electrode material, and nickel or the like is used as a current collector in contact with a negative electrode material. Discharging occurs.
  • a separator made of metal functions as a current collector and takes out current to the outside.
  • Patent Document 4 proposes that a coating made of conductive graphite is formed on a substrate made of aluminum by sputtering to increase the corrosion resistance while having conductivity, and this is used as a separator for a fuel cell.
  • the first invention has been made in view of the above points, and an object thereof is to provide a positive electrode for a secondary battery in which a charging reaction is performed at a high potential and a positive electrode active material having a high energy density can be effectively used.
  • a positive electrode for a secondary battery according to a first aspect of the present invention is the positive electrode for a secondary battery containing a positive electrode active material and a conductive additive, wherein the conductive additive includes at least conductive diamond-like carbon powder and glassy carbon powder.
  • the conductive additive includes at least conductive diamond-like carbon powder and glassy carbon powder.
  • One type is included.
  • the conductive assistant contains at least one of conductive diamond-like carbon powder and glassy carbon powder.
  • diamond-like carbon and glassy carbon have a wider potential window than graphite, are stable at a high potential, are less likely to decompose the solvent, and have electron conductivity. Is also excellent.
  • the high conductivity necessary for the positive electrode can be secured and it is not oxidized at a high potential during charging. Or the solvent can be prevented from decomposing. Therefore, the charging reaction is performed at a high potential, and the positive electrode active material having a high energy density can be effectively used.
  • the conductive diamond-like carbon is carbon having an amorphous structure in which both diamond bonds (SP 3 hybrid orbital bonds between carbons) and graphite bonds (SP 2 hybrid orbital bonds between carbons) are mixed. Among them, the one whose conductivity is 1000 ⁇ cm or less. However, in addition to the amorphous structure, those having a phase composed of a crystal structure partially composed of a graphite structure (that is, a hexagonal crystal structure composed of SP 2 hybrid orbital bonds) and thereby exhibiting conductivity are also included. . Diamond-like carbon having properties intermediate between graphite and diamond adjusts the conductivity by adjusting the ratio of SP 2 hybrid orbital bonds and SP 3 hybrid orbital bonds of the carbon atoms constituting diamond-like carbon during film formation. be able to.
  • Li 2 NiPO 4 F As the positive electrode active material used in the positive electrode for secondary battery of the first invention, Li 2 NiPO 4 F, it may comprise at least one LiNiPO 4, LiCoPO 4 and Li 2 CoPO 4 F. Since these positive electrode active materials are charged at a high potential, there is an advantage that the energy density is large, but there is a possibility that the conventional conductive assistant made of graphite is oxidized or the solvent is decomposed. On the other hand, in the positive electrode for secondary battery of the present invention using diamond-like carbon or glassy carbon as a conductive assistant, the potential window is wide and the conductive assistant is difficult to be oxidized or decomposed. It can be suitably used as a lithium ion battery that can effectively utilize the advantages of these positive electrode active materials.
  • the electrolyte solution containing the nitrile compound is charged in a wide since it has a potential window, Li 2 NiPO 4 F, LiNiPO 4, LiCoPO 4 and Li 2 CoPO 4 F higher potential of such It exists stably in the charged region of the positive electrode active material, and can withstand decomposition. For this reason, it is suitable as an electrolytic solution for the positive electrode for the secondary battery of the present invention.
  • the secondary battery of the present invention is characterized by including the positive electrode for the secondary battery of the first invention and an electrolytic solution containing a nitrile compound.
  • the second invention has been made in view of the above points, and provides a positive electrode for a secondary battery capable of effectively utilizing a positive electrode active material having a high energy density in which a charging reaction is performed at a high potential. Objective.
  • the positive electrode for a secondary battery of the second invention is a positive electrode for a secondary battery in which an aggregate of particles made of a positive electrode active material is formed into a predetermined shape.
  • the particles made of the positive electrode active material are electrically conductive by a dry plating method. It is characterized in that a conductive diamond-like carbon is adhered.
  • an aggregate of particles made of a positive electrode active material is formed into a predetermined shape, and conductive diamond-like carbon adheres to the particles made of the positive electrode active material by a dry plating method.
  • conductive diamond-like carbon plays the role of a conductive additive, and imparts electronic conductivity, which is a necessary characteristic for the positive electrode for secondary batteries.
  • diamond-like carbon has a wider potential window than graphite, is stable at a high potential, and is less likely to decompose the solvent. For this reason, there is little possibility that diamond-like carbon is oxidized or the solvent is decomposed at a high potential during charging. For this reason, the positive electrode active material with a high energy density in which a charging reaction is performed at a high potential can be effectively utilized.
  • the conductive diamond-like carbon is carbon having an amorphous structure in which both diamond bonds (SP 3 hybrid orbital bonds between carbons) and graphite bonds (SP 2 hybrid orbital bonds between carbons) are mixed. Among them, the one whose conductivity is 1000 ⁇ cm or less. However, in addition to the amorphous structure, those having a phase composed of a crystal structure partially composed of a graphite structure (that is, a hexagonal crystal structure composed of SP 2 hybrid orbital bonds) and thereby exhibiting conductivity are also included. . Diamond-like carbon having properties intermediate between graphite and diamond adjusts the conductivity by adjusting the ratio of SP 2 hybrid orbital bonds and SP 3 hybrid orbital bonds of the carbon atoms constituting diamond-like carbon during film formation. be able to.
  • Li 2 NiPO 4 F may comprise at least one LiNiPO 4, LiCoPO 4 and Li 2 CoPO 4 F. Since these positive electrode active materials are charged at a high potential, there is an advantage that the energy density is large. However, there is a possibility that the graphite is oxidized or the solvent is decomposed with the conventional conductive assistant made of graphite. . On the other hand, in the positive electrode for a secondary battery of the present invention, even if the potential is high, stable diamond-like carbon works as a conductive assistant, and the potential window is wide so that the solvent is not easily decomposed. For this reason, it can use suitably as a lithium ion battery which can utilize effectively the advantage of these positive electrode active materials with a large energy density.
  • the electrolyte solution containing the nitrile compound is charged in a wide since it has a potential window, Li 2 NiPO 4 F, LiNiPO 4, LiCoPO 4 and Li 2 CoPO 4 F higher potential of such It exists stably in the charged region of the positive electrode active material, and can withstand decomposition. For this reason, it is suitable as an electrolytic solution for the positive electrode for the secondary battery of the present invention.
  • the secondary battery of the second invention is characterized by comprising the positive electrode for the secondary battery of the second invention and an electrolytic solution containing a nitrile compound.
  • Various electrode active material Li 2 NiPO 4 F in example lithium-ion battery, LiNiPO 4, LiCoPO 4, Li 2 CoPO 4 F positive electrode active material, etc.
  • the electrolyte salt is a salt that does not easily form a fluorine compound or a complex compound of fluorine and oxygen, such as LiTFSI or LiBETI, There has been a problem that a corrosion current unrelated to charging / discharging of Li flows on aluminum as an electric material.
  • the electrolyte salt is a salt that easily forms a fluorine compound or a compound compound of fluorine and oxygen represented by AlO x / 2 F 3-x , such as LiBF 4 or LiPF 6 (see Non-Patent Document 1).
  • the thickness of the passive film having a large electronic resistance to aluminum increases.
  • the passivation proceeds more than the contact area between the substrate forming the electron path and the conductive additive, and the electron path is narrowed, so that the ohmic overvoltage increases and there is a great possibility that the high output is hindered. There are concerns.
  • the third invention has been made in view of the above-described conventional situation, and has a current collector that has conductivity even in a severe corrosive environment and exhibits excellent corrosion resistance, and a positive electrode active material that is charged at a high potential. It is an issue to be solved to provide a battery that exhibits excellent corrosion resistance even with a battery using a substance.
  • the first battery is made of conductive diamond-like carbon, glassy carbon, gold and platinum on the surface of a current collector base material mainly composed of aluminum, nickel or titanium or a current collector base material made of austenitic stainless steel.
  • a battery comprising an organic solvent The organic solvent includes a chain saturated hydrocarbon dinitrile compound in which a nitrile group is bonded to both ends of a chain saturated hydrocarbon compound, and a chain ether nitrile compound in which a nitrile group is bonded to at least one terminal of a chain ether compound. And at least one nitrile compound of cyanoacetate and at least one of cyclic carbonate, cyclic ester and chain carbonate.
  • conductive diamond-like carbon, glassy carbon, gold, and platinum are formed on the surface of a current collector base material mainly composed of aluminum, nickel, or titanium or a current collector base material made of austenitic stainless steel. Since the current collector on which a conductive corrosion-resistant film made of one or more of them is formed is used, the current collector exhibits excellent corrosion resistance.
  • the electrolytic solution is a chain saturated hydrocarbon dinitrile compound in which a nitrile group is bonded to both ends of a chain saturated hydrocarbon compound, or a chain ether nitrile compound in which a nitrile group is bonded to at least one terminal of a chain ether compound.
  • an organic solvent containing at least one nitrile compound of cyanoacetate and at least one of cyclic carbonate, cyclic ester and chain carbonate is formed on an electrode or an electrical power collector, and it becomes a battery which has the further outstanding corrosion resistance with respect to electrolyte solution.
  • the current collector of the present invention has conductive diamond-like carbon, glassy carbon, gold and the like on the surface of a current collector base material comprising aluminum, nickel or titanium as a main constituent or a current collector base material made of austenitic stainless steel.
  • a current collector base material mainly composed of aluminum, nickel or titanium or a current collector base material made of austenitic stainless steel is used.
  • “having aluminum, nickel, or titanium as a main constituent” refers to a metal containing 90% by mass or more of aluminum, nickel, or titanium.
  • electrolyte salt is LiTFSI
  • a salt such as LiBETI that does not readily form a fluorine compound or a compound compound of fluorine and oxygen that has corrosion resistance, it is far more than the collector in which aluminum, nickel, titanium, or austenitic stainless steel is exposed. Therefore, the current collector has a wide potential window with high electron conductivity and excellent corrosion resistance.
  • the surface of the current collector base that is exposed to defects in the corrosion-resistant film is one of the fluorine compound, oxygen compound, nitrogen compound, carbon compound, phosphorus compound, and boron compound of the current collector base.
  • the passive film which consists of 2 or more types, the progress of corrosion from the defect which exists in a corrosion-resistant film
  • membrane is prevented by this passive film. For this reason, it has much higher conductivity and excellent corrosion resistance than a current collector made of aluminum, nickel, titanium, or austenitic stainless steel, as in the case where there is no defect in the conductive corrosion-resistant film. It becomes a current collector.
  • austenitic stainless steel one or more of SUS304, SUS316, and SUS306L defined by Japanese Industrial Standard can be used.
  • the electrolyte salt is a salt that easily forms a fluoride, such as LiBF 4 or LiPF 6
  • a fluorine compound with high electronic resistance or fluorine and oxygen formed on aluminum or the like as the potential increases.
  • corrosion resistance can be secured even at a high potential of 10 V or higher.
  • the electronic conductivity of the passive film portion made of a fluorine compound or a composite compound of fluorine and oxygen is lowered, but in the current collector of the present invention, most of the current collector base material has conductivity.
  • the decrease in electron conductivity due to the passive film on the current collector substrate is caused by a very small area of the defective portion. Only occurs. Therefore, even if the voltage is increased, the decrease in electron conductivity is negligible, and it is possible to prevent the decrease in output caused by the increased voltage.
  • the conductive diamond-like carbon is a carbon having an amorphous structure in which both diamond bonds (SP 3 hybrid orbital bonds between carbons) and graphite bonds (SP 2 hybrid orbital bonds between carbons) are mixed. Among them, the one whose conductivity is 1000 ⁇ cm or less. However, in addition to the amorphous structure, those having a phase composed of a crystal structure partially composed of a graphite structure (that is, a hexagonal crystal structure composed of SP 2 hybrid orbital bonds) and thereby exhibiting conductivity are also included. .
  • Diamond-like carbon having properties intermediate between graphite and diamond adjusts the conductivity by adjusting the ratio of SP 2 hybrid orbital bonds and SP 3 hybrid orbital bonds of the carbon atoms constituting diamond-like carbon during film formation. be able to.
  • the conductivity and corrosion resistance can be adjusted by substituting trace elements for different elements other than carbon. Examples of the different elements include Ti, Cr, Al, Fe, Ni, Cu, Ag, Mo, W, B, and Si.
  • the current collector of the present invention is extremely excellent in corrosion resistance and has a wide potential window
  • the current collectors of various electric storage devices such as lithium ion batteries and sodium ion batteries with high charging voltage, such as electric double layer capacitors and lithium ion capacitors. It can be suitably used as a body.
  • the second battery of the present invention has conductive diamond-like carbon, glassy carbon, gold on the surface of a current collector base material composed mainly of aluminum, nickel or titanium or a current collector base material made of austenitic stainless steel. And a current collector on which a conductive corrosion-resistant film made of one or more of platinum is formed, and an electrolytic solution containing an electrolyte having at least one of BF 4 anion and PF 6 anion. It is characterized by.
  • conductive diamond-like carbon, glassy carbon, on the surface of a current collector base material comprising aluminum, nickel or titanium as a main component or a current collector base material made of austenitic stainless steel Since the current collector on which a conductive corrosion-resistant film made of one or more of gold and platinum is formed is used, the current collector exhibits excellent corrosion resistance. Furthermore, since the electrolyte has at least one of BF 4 anion and PF 6 anion, an excellent corrosion-resistant film containing fluorine or the like is formed.
  • the electrolyte includes a chain saturated hydrocarbon dinitrile compound in which a nitrile group is bonded to both ends of the chain saturated hydrocarbon compound, and a nitrile group at least at one end of the chain ether compound.
  • An organic solvent containing at least one nitrile compound among a chain ether nitrile compound and a cyanoacetate bonded to each other and at least one of a cyclic carbonate, a cyclic ester, and a chain carbonate may be included. If it is like this, the outstanding corrosion-resistant film
  • FIG. 5 is a potential-current curve of conductive assistants for secondary battery positive electrodes of Experimental Examples 1 to 3 and Comparative Examples 1 to 3 in an electrolyte solution of 1M LiPF 6 / EC-DMC-sebacononitrile (capacity ratio 25:25:50). .
  • Conductive aid for positive electrodes for secondary batteries of Experimental Examples 1, 3 and 4 and Comparative Examples 1 to 3 and Comparative Examples 1 to 3 in an electrolyte solution of 1M LiTFSI / EC-DMC-Sebacononitrile (capacity ratio 25:25:50) Is a potential-current curve.
  • 6 is a potential-current curve of positive electrodes for secondary batteries of Experimental Example 1 and Comparative Examples 1 to 3.
  • It is a schematic diagram which shows the preparation methods of the electrical power collector of embodiment. 6 is a graph showing the relationship between potential and current in the electrodes of Example 1 and Comparative Examples 1 to 4.
  • 10 is a graph showing the relationship between potential and current in an electrode of Example 7.
  • 6 is a graph showing the relationship between potential and current in the electrodes of Example 8 and Comparative Examples 12 to 20.
  • 10 is a graph showing the relationship between potential and current in electrodes of Example 9 and Comparative Examples 21 to 22.
  • 10 is a graph showing the relationship between potential and current in an electrode of Example 9. It is a schematic cross section of a lithium ion battery using the current collector of the embodiment.
  • 2 is a potential-current curve of Example 1 and Comparative Example 1.
  • FIG. 2 is a potential-current curve of Examples 2 to 9 and Comparative Example 1.
  • FIG. 3 is a potential-current curve of Comparative Example 1.
  • 6 is a potential-current curve of Examples 10 to 17 and Comparative Example 2.
  • FIG. 6 is a potential-current curve of Examples 18 to 25 and Comparative Example 3.
  • FIG. 6 is a potential-current curve of Examples 26 to 31 and Comparative Example 4.
  • FIG. 6 is a potential-current curve of Examples 32 and 33 and Comparative Example 5.
  • 6 is a potential-current curve of Examples 34 to 36 and Comparative Example 6.
  • FIG. 10 is a potential-current curve of Examples 37 to 39 and Comparative Example 7. 2 is a potential-current curve of Examples 41 to 45 and Comparative Example 1.
  • FIG. 6 is a potential-current curve of Example 45 and Comparative Example 8.
  • FIG. 10 is a potential-current curve of Example 46 and Comparative Example 8.
  • 6 is a potential-current curve of Example 47 and Comparative Example 1.
  • a positive electrode active material powder is prepared, and a glassy carbon powder (and / or diamond-like carbon powder) as a conductive auxiliary agent and polytetraethylene (PTFE) or polyvinylidene fluoride (as a binder) PVdF) or other fluororesin powder is added and formed into a desired shape by hot pressing to obtain the positive electrode for secondary battery of the embodiment.
  • PTFE polytetraethylene
  • PVdF polyvinylidene fluoride
  • the positive electrode active material for example, Li 2 NiPO 4 F, LiNiPO 4 , LiCoPO 4, Li 2 CoPO 4 either F or the like, or may be a mixture thereof.
  • mixing ratios may be appropriately determined in consideration of the electron conductivity required for the positive electrode, the addition amount of the fluororesin necessary for exhibiting the function as the binder, and the like.
  • Typical ratios of the positive electrode active material powder are 60 to 80% by weight, the glassy carbon powder is 15 to 35% by weight, and the fluororesin powder is 3 to 10% by weight.
  • the lithium ion battery 8 as shown in FIG. 1 can be manufactured using the positive electrode for a lithium ion battery thus formed. That is, the separator 1 through which the electrolytic solution can permeate is sandwiched between the positive electrode 2 for a lithium ion battery and the negative electrode 3 made of graphite to form a joined body 4 and immersed in the electrolytic solution. Then, the joined body 4 is accommodated so that the negative electrode 3 is in contact with the negative electrode current collecting case 6 loaded with the packing 5, and the positive electrode current collector plate 7 is inserted from the positive electrode 2 side for the lithium ion battery. The current collecting case 6 and the positive current collecting plate 7 are caulked and sealed. Thus, the lithium ion battery 8 of the embodiment can be manufactured.
  • the glassy carbon powder 2b and the fluororesin powder 2c are attached on the positive electrode active material powder 2a. 2c holds each powder together as a binder to maintain the electrode shape. And the glassy carbon powder 2b plays a role as a conductive auxiliary agent responsible for electron conductivity. As will be described later, the glassy carbon powder 2b (or diamond-like carbon powder) has a wider potential window than the simple carbon black powder or graphite powder in the electrolyte of the lithium ion battery.
  • the conductive auxiliary agent is not oxidized at a high potential during charging or the solvent is not decomposed. As a result, a charging reaction is performed at a high potential, and a positive electrode active material having a high energy density is obtained. It can be used effectively.
  • Example 1 In Experimental Example 1, 4 mg of glassy carbon powder (average particle size 0.5 ⁇ m) and 1 mg of PTFE powder were mixed, and an 8 mm ⁇ disc-shaped electrode was produced by hot pressing.
  • Example 2 In Experimental Example 2, 4 mg of a glassy carbon pulverized product (average particle diameter: 8 ⁇ m) and 1 mg of PTFE powder were mixed, and an 8 mm ⁇ disk-shaped electrode was produced by hot pressing.
  • Example 3 In Experimental Example 3, 4 mg of diamond-like carbon powder (average particle size 0.03 ⁇ m) and 1 mg of PTFE powder were mixed, and an 8 mm ⁇ disk-shaped electrode was produced by hot pressing.
  • Example 4 In Experimental Example 4, 4 mg of a Pt-supported glassy carbon product on which 20% by weight of Pt was supported on a glassy carbon product (average particle size of 0.5 ⁇ m) and 1 mg of PTFE powder were mixed, and a disk shape of 8 mm ⁇ was formed by hot pressing. An electrode was prepared.
  • Comparative Example 1 is a commercially available glassy carbon plate itself.
  • Comparative Example 2 In Comparative Example 2, 15 mg of carbon black (“HS-100” manufactured by Denki Kagaku Kogyo Co., Ltd.) and 15 mg of PTFE powder were mixed, and an 8 mm ⁇ disk-shaped electrode was produced by hot pressing.
  • carbon black (“HS-100” manufactured by Denki Kagaku Kogyo Co., Ltd.)
  • PTFE powder 15 mg
  • the electrodes of Experimental Examples 1 to 3 and Comparative Examples 1 to 3 produced as described above were subjected to potential scanning in an electrolytic solution for a lithium ion battery, and a potential-current curve was measured.
  • the electrolytic solution was prepared as follows. That is, a mixed solution was prepared such that ethylene carbonate, dimethyl carbonate, and sebaconitrile were in a volume ratio of 25:25:50, and a solution in which LiPF 6 was dissolved so as to be 1 mol / L was used as an electrolytic solution. Placed in an electrolytic cell container.
  • the above electrode (area 0.5 cm 2 ) was used as a working electrode, a platinum net as a counter electrode, and Li metal as a reference electrode.
  • the sweep speed was 5 mV / sec.
  • the electrodes of Experimental Examples 1 and 2 using glassy carbon powder and Experimental Example 3 using diamond-like carbon have a wider potential than the glassy carbon plate electrode of Comparative Example 1. It turns out that it has a window.
  • Comparative Example 2 in which carbon black was used as an electrode as it was the potential window was narrow
  • Comparative Example 3 in which carbon black was heat-treated and graphitized the potential window was slightly widened, but at about 4.8V. It was 50 ⁇ A / cm 2 , indicating that the potential window was narrow compared to Experimental Examples 1 to 3.
  • the electrolyte was changed to 1M LiBF4 and the same measurement was performed. The result is shown in FIG.
  • Example 4 it was found that the potential window widened on the high potential side. Further, the same test was performed by changing the electrolyte to 1M LiTFSI. The result is shown in FIG. Also in this case, the potential window is widened on the high potential side in the experimental example 1 of the crushed glassy carbon product than in the comparative example 3 in which the carbon black in the comparative example 2 in the comparative example 2 or the carbon black is graphitized by heat treatment. I understood.
  • a positive electrode active material powder is prepared, and diamond-like carbon is adhered to the surface of the positive electrode active material powder by dry plating.
  • a dry-type plating method for making diamond-like carbon adhere to the powder of a positive electrode active material For example, an ionization vapor deposition method can be used. In other words, benzene or hydrocarbon gas is introduced into a vacuum chamber, ions are generated in a DC arc discharge plasma, and collided with a positive active material powder biased to a DC negative voltage with energy corresponding to the bias voltage. In this method, diamond-like carbon is attached to the surface of the positive electrode active material powder.
  • a high-frequency plasma method can be mentioned.
  • methane gas is used as a raw material, and a capacitively coupled plasma electrode is used.
  • diamond-like carbon can be attached to the powder of the positive electrode active material by thermal decomposition of hydrocarbon gas (for example, JP 2008-260670 A).
  • diamond-like carbon can be attached to the surface of the positive electrode active material powder by a sputtering method (for example, JP-A-2004-339564). That is, in a vacuum, electrons are accelerated by an electric field and collided with argon gas to ionize argon, which is accelerated by the electric field and collided with a solid carbon target to be sputtered, and diamond-like carbon is formed on the positive electrode active material powder. (At this time, a negative bias voltage applied to the positive electrode active material may be applied).
  • a sputtering method for example, JP-A-2004-339564. That is, in a vacuum, electrons are accelerated by an electric field and collided with argon gas to ionize argon, which is accelerated by the electric field and collided with a solid carbon target to be sputtered, and diamond-like carbon is formed on the positive electrode active material powder. (At this time, a negative bias voltage applied to the positive electrode active
  • a positive electrode active material powder having diamond-like carbon attached to the surface is prepared by various dry plating methods as described above, and polytetraethylene (PTFE), polyvinylidene fluoride (PVdF), or the like as a binder is prepared. Are added into a desired shape by hot pressing to obtain the positive electrode for secondary battery of the embodiment.
  • PTFE polytetraethylene
  • PVdF polyvinylidene fluoride
  • the positive electrode active material for example, Li 2 NiPO 4 F, LiNiPO 4 , LiCoPO 4, Li 2 CoPO 4 either F or the like, or may be a mixture thereof. These mixing ratios may be appropriately determined in consideration of the electron conductivity required for the positive electrode, the addition amount of the fluororesin necessary for exhibiting the function as the binder, and the like.
  • a lithium ion battery 18 as shown in FIG. 6 can be manufactured using the positive electrode for a lithium ion battery thus formed. That is, the separator 11 into which the electrolytic solution can permeate is sandwiched between the lithium ion battery positive electrode 2 and the negative electrode 13 made of graphite to form a joined body 14 and immersed in the electrolytic solution. Then, the joined body 14 is accommodated so that the negative electrode 13 is in contact with the negative electrode current collecting case 16 loaded with the packing 15, and the positive electrode current collector plate 17 is inserted from the positive electrode 12 side for the lithium ion battery. The current collecting case 16 and the positive current collecting plate 17 are caulked and sealed. Thus, the lithium ion battery 18 of the embodiment can be manufactured.
  • the diamond-like carbon 12b and the fluororesin powder 12c are attached on the positive electrode active material powder 12a, and the fluororesin powder 12c.
  • the powder is held as a binder to maintain the electrode shape.
  • the diamond-like carbon 12b plays a role as a conductive auxiliary agent responsible for electronic conductivity. As will be described later, the diamond-like carbon 12b has a wider potential window in the electrolyte of a lithium ion battery than a simple carbon black powder or graphite powder.
  • the conductive auxiliary agent is not oxidized at a high potential during charging or the solvent is not decomposed. As a result, a charging reaction is performed at a high potential, and a positive electrode active material having a high energy density is obtained. It can be used effectively.
  • Example 1 In Experimental Example 1, 4 mg of diamond-like carbon powder (average particle size 0.03 ⁇ m) and 1 mg of PTFE powder were mixed, and an 8 mm ⁇ disk-shaped electrode was produced by hot pressing.
  • Comparative Example 1 is a commercially available glassy carbon plate itself.
  • Comparative Example 2 In Comparative Example 2, 15 mg of carbon black (“HS-100” manufactured by Denki Kagaku Kogyo Co., Ltd.) and 15 mg of PTFE powder were mixed, and an 8 mm ⁇ disk-shaped electrode was produced by hot pressing.
  • carbon black (“HS-100” manufactured by Denki Kagaku Kogyo Co., Ltd.)
  • PTFE powder 15 mg
  • the electrodes of Experimental Example 1 and Comparative Examples 1 to 3 produced as described above were subjected to potential scanning in an electrolyte for a lithium ion battery, and a potential-current curve was measured.
  • the electrolytic solution was prepared as follows. That is, a mixed solution was prepared so that ethylene carbonate, dimethyl carbonate, and sebaconitrile were in a mass ratio of 25:25:50, and a solution in which LiPF 6 was dissolved to 1 mol / L was used as an electrolytic solution. Placed in an electrolytic cell container.
  • the above electrode (area 0.5 cm 2 ) was used as a working electrode, a platinum net as a counter electrode, and Li metal as a reference electrode.
  • the sweep speed was 5 mV / sec.
  • the positive electrode for the lithium ion battery of the embodiment in which diamond-like carbon was attached to the positive electrode active material powder of the lithium battery by a dry plating method and further mixed with a fluororesin powder was formed by lithium ion It can be seen that even in a positive electrode that is set to a high potential during charging for a battery, the solvent is not likely to be decomposed without being decomposed. From this result, it was found that a positive electrode active material having a high energy density in which a charging reaction is performed at a high potential can be effectively used.
  • ⁇ Third invention ⁇ (Embodiment 1) As shown in FIG. 9, a base material 21 made of aluminum, nickel, titanium, or austenitic stainless steel (for example, SUS304, SUS316, SUS306L, etc.) is prepared, and a corrosion-resistant film 22 made of conductive diamond-like carbon is formed thereon.
  • a base material 21 made of aluminum, nickel, titanium, or austenitic stainless steel for example, SUS304, SUS316, SUS306L, etc.
  • CVD method thermal CVD, plasma CVD (high frequency, microwave, direct current, etc.), PVD method, vacuum deposition method, ion plating (direct current excitation, high frequency excitation) ) Method, sputtering method (bipolar sputtering, magnetron sputtering, ECR sputtering), laser ablation method, ion beam deposition, ion implantation method and the like.
  • a more specific method for the plasma CVD method and the PVD method is as follows. (1) Method of forming diamond-like carbon film by plasma CVD method A collector base material is placed in the chamber, a hydrocarbon gas such as acetylene is introduced into the chamber, it is turned into plasma by electromagnetic induction, and carbonized by vapor phase synthesis. Hydrogen is deposited on the surface of the current collector substrate.
  • the diamond-like carbon film by this method always contains hydrogen because the raw material contains hydrogen.
  • This manufacturing method has many industrial advantages such as that the temperature of the current collector base material does not need to be so high, and it is easy to form a uniform film even in a complicated shape by the arrangement of electrodes, and the processing time is relatively short.
  • the surface of the current collector base 21 exposed from the defects 23 present in the conductive corrosion-resistant film 22 is made of one or more of fluorine compounds, oxygen compounds, nitrogen compounds, carbon compounds and phosphorus compounds.
  • Cover with a passive film 24 For example, it is known that a passive film is formed when aluminum is treated at high potential in the electrolyte of a lithium ion battery (2000 Electrochemical Society. Abstracts of Autumn Meeting, p.17 (2000) ), Surface technology Vol.58, No.6, p337-341 (2007)), this phenomenon can be used to form a passive film 24 on defects in the corrosion-resistant film.
  • the current collector base material 21 on which the conductive corrosion-resistant film 2 is formed is immersed in a cyclic carbonate and / or chain carbonate solution of LiPF 6 , LiBF 4 or LiClO 4 used as an electrolyte of a lithium ion battery.
  • a potential required for charging (more desirably, a potential of about 6 V to 7 V with respect to the reference electrode (Li / Li + )) may be used.
  • the current collector of the present invention is obtained.
  • a conductive corrosion-resistant film made of glassy carbon can also be used.
  • Such a corrosion-resistant film can be formed, for example, by the method described in JP-A-11-4377. That is, a current collector base material made of a metal such as titanium is subjected to plasma heat treatment in an atmosphere containing 0.1 to 30 torr and 400 to 1100 ° C. containing a hydrocarbon gas such as methane, ethane, or propane. Thereby, a glassy carbon film is formed on the surface of the current collector substrate.
  • a conductive corrosion-resistant film made of gold or platinum can also be used.
  • the PVD apparatus is provided with gold or platinum as a target electrode, a current collector base is placed in the chamber, the apparatus is evacuated, a gas serving as an ion source is slightly introduced, and the current collector base Discharge is performed while applying a high negative voltage to the material.
  • the ionized introduced gas is accelerated by the voltage and collides with the target electrode, causing a sputtering phenomenon.
  • the sputtered gold or platinum particles adhere to the surface of the current collector substrate, and a conductive corrosion-resistant film can be formed.
  • Example 1 an electrode in which a conductive diamond-like carbon film was formed on the surface of an aluminum electrode by plasma CVD was prepared, and the potential was scanned in an electrolyte for a lithium ion battery, and a potential-current curve was measured.
  • the electrolytic solution was prepared as follows. That is, a mixed solution was prepared so that ethylene carbonate, dimethyl carbonate, and sebaconitrile were in a mass ratio of 25:25:50, and a solution in which LiPF 6 was dissolved to 1 mol / L was used as an electrolytic solution. Placed in an electrolytic cell container.
  • an electrode (area 0.5 cm 2 ) was used as a working electrode, a platinum mesh was used as a counter electrode, and Li metal was used as a reference electrode.
  • the measurement was performed by scanning the reference electrode three times between 3V and 8V, and measuring the potential-current curve. The sweep speed was 5 mV / sec.
  • Comparative Example 1 An aluminum substrate was subjected to potential scanning in an electrolytic solution for a lithium ion battery in the same manner as in Example 1, and a potential-current curve was measured. Furthermore, the surface analysis by XPS was performed about the aluminum electrode which finished the potential scan.
  • Comparative Example 2 In Comparative Example 1, a potential-current curve was measured by scanning the potential of the gold electrode in the electrolyte for a lithium ion battery in the same manner as in Example 1.
  • Comparative Example 3 (Comparative Example 3)
  • the potential-current curve was measured by scanning the potential of the platinum electrode in the electrolyte for a lithium ion battery in the same manner as in Example 1.
  • Comparative Example 4 the potential-current curve was measured by scanning the potential of the glassy carbon electrode in the electrolyte for a lithium ion battery in the same manner as in Example 1.
  • the electrode of Example 1 in which the film made of conductive diamond-like carbon was formed on the aluminum electrode, almost no current flows up to about 6.4 V even in the first scan, and about 50 ⁇ A even at 7.2 V. It was found that the corrosion resistance was also excellent after the second time. Further, from comparison with the potential-current curves of Comparative Example 2 (gold electrode), Comparative Example 3 (platinum electrode), and Comparative Example 4 (glassy carbon), the electrode of Example 1 has better corrosion resistance than gold and platinum. It has been found that the glass has the same corrosion resistance as that of glassy carbon.
  • Example 2 As the electrode substrate on the working electrode side, an electrode in which a diamond-like carbon film was formed on the surface of a nickel plate by a plasma CVD method was used, and LiBF 4 was used as an electrolyte.
  • the other measurement conditions are the same as in Experimental Example 1, and detailed description thereof is omitted.
  • Comparative Example 5 the potential-current curve was measured by scanning the potential of the nickel substrate in the electrolyte for a lithium ion battery in the same manner as in Example 2. Furthermore, the surface analysis by XPS was performed about the nickel electrode which finished sweeping.
  • Comparative Example 6 (Comparative Example 6)
  • the potential-current curve was measured by scanning the potential of the platinum electrode in the electrolyte for a lithium ion battery in the same manner as in Example 2.
  • Comparative Example 7 (Comparative Example 7)
  • the potential-current curve was measured by scanning the potential of the glassy carbon electrode in the electrolyte for a lithium ion battery in the same manner as in Example 2.
  • Example 2 in which a film made of conductive diamond-like carbon was formed on the nickel electrode, as shown in FIG. 12, almost no current flows up to about 6.4 V even in the first scan. In the second scan, the potential window further spreads to the high potential side by about 0.2V. Further, by comparing with the potential-current curve of Comparative Example 6 (platinum electrode), it was found that the electrode of Example 2 exhibited better corrosion resistance than platinum.
  • Example 3 an electrode having a diamond-like carbon film formed on the surface of a titanium plate by a plasma CVD method was used as the electrode base on the working electrode side.
  • the other measurement conditions are the same as in Example 1, and detailed description thereof is omitted.
  • Comparative Example 8 In Comparative Example 8, the potential-current curve was measured by scanning the potential of the titanium substrate in the electrolyte for a lithium ion battery in the same manner as in Example 1. Furthermore, the surface analysis by XPS was performed about the nickel electrode which finished sweeping.
  • Example 3 in which a film made of conductive diamond-like carbon was formed on the titanium electrode, as shown in FIG. In the second scan, it was found that the same level of corrosion resistance was exhibited.
  • Example 4 In Examples 4 to 6, a diamond-like carbon film was formed on the surface of an austenitic stainless steel (SUS304 in Example 4, SUS316 in Example 5 and SUS316L in Example 6) by plasma CVD as an electrode base on the working electrode side. The formed electrode was used. The other measurement conditions are the same as in Example 1, and detailed description thereof is omitted.
  • Comparative Examples 9 to 11 In Comparative Examples 9 to 11, the austenitic stainless steel (Comparative Example 9 is SUS304, Comparative Example 10 is SUS316, and Comparative Example 11 is SUS316L). The potential-current curve was measured.
  • Example 7 After forming a diamond-like carbon film on an aluminum substrate in the same manner as in Example 1, an electrode whose surface was intentionally scratched by cutting glass made of diamond was used.
  • an electrode whose surface was intentionally scratched by cutting glass made of diamond was used.
  • a mixed solution of ethylene carbonate, dimethyl carbonate, and sebaconitrile was prepared at a mass ratio of 25:25:50, and LiPF was further added.
  • a potential-current curve was measured using a solution in which 6 was dissolved at 1 mol / L as an electrolyte.
  • the electrode of Example 1 since most of the surface of the aluminum base material is covered with conductive diamond-like carbon, a conductive diamond-like carbon film having no defects is formed as in the electrode of Example 1.
  • the electrode has a wide potential window as in the case of the electrode.
  • Example 8 The electrode of Example 8 is an electrode in which a diamond-like carbon film having no defect is formed on a titanium substrate in the same manner as in Example 3.
  • Comparative Examples 12 to 20 Comparative Example 12 for an untreated titanium electrode, Comparative Example 13 for an untreated aluminum electrode, Comparative Example 14 for an untreated nickel electrode, Comparative Example 15 for an untreated SUS304 electrode, Comparative Example 16 for an untreated SUS316 electrode,
  • the untreated SUS316L electrode was designated as Comparative Example 17, the untreated glassy carbon electrode as Comparative Example 18, the untreated platinum electrode as Comparative Example 19, and the untreated gold electrode as Comparative Example 20.
  • Comparative Example 12 titanium
  • Comparative Example 13 aluminum
  • Comparative Example 14 nickel
  • Comparative Examples 15 to 17 austenitic series
  • the potential windows of the electrodes of Comparative Example 18 (Glassy Carbon), Comparative Example 19 (Platinum), and Comparative Example 20 (Gold) are Comparative Example 12 (Titanium), Comparative Example 13 (Aluminum), and Comparative Example 14 (Nickel).
  • the potential window is wider than those of Comparative Examples 15 to 17 (austenitic stainless steel), about 6.3 V (vs Li / Li + ) in comparative example 18 (glassy carbon), and 5.9 V (vs in comparative example 19 (platinum)). Li / Li +) or so, it was the Comparative example 20 (gold) 5.8V (vs Li / Li + ) degree.
  • the electrode of Comparative Example 21 was an electrode in which a diamond-like carbon film was formed on an aluminum substrate in the same manner as in Example 1, and then the surface was intentionally damaged by cutting glass made of diamond.
  • the electrode of Comparative Example 22 is an electrode in which a diamond-like carbon film was formed on a nickel substrate in the same manner as in Example 2, and then the surface was intentionally damaged by cutting glass made of diamond.
  • Example 8 with no defect an electrode in which a diamond-like carbon film having no defect is formed on a titanium substrate
  • the current is almost up to about 6 V (vs Li / Li + ).
  • the electrode of Comparative Example 21 that is, the electrode that was damaged after forming a diamond-like carbon film on the aluminum substrate
  • a very small amount of corrosion current starts to flow from the vicinity (Comparative Example 21).
  • a large current suddenly flowed from around 6.3 V (vs Li / Li + ) where the reaction current began to flow on the conductive diamond-like carbon.
  • the corrosion current was higher than the vicinity of 5 V (vs Li / Li + ) as in the nickel electrode. Began to flow. From the above results, it can be seen that when the conductive diamond-like carbon film has a defect and the substrate touches the electrolyte at that defect, the corrosion current starts to flow around the same potential as the potential for corrosion of the substrate. It was. Further, even if a glassy carbon, platinum, or gold film is formed, if the film is defective, similar to the electrodes of Comparative Examples 21 and 22, near the potential at which corrosion of the substrate occurs. It can be easily guessed that the corrosion current starts to flow.
  • Example 9 The electrode of Example 9 is the electrode of Example 7 (that is, after a diamond-like carbon film was formed on an aluminum substrate in the same manner as in Example 1, the surface was intentionally damaged by cutting glass made of diamond.
  • a mixed solution of ethylene carbonate, dimethyl carbonate, and sebaconitrile is prepared at a mass ratio of 25:25:50, and a solution in which LiPF 6 is dissolved at 1 mol / L is used as an electrolytic solution.
  • the electrode after potential sweep in which the potential-current curve was measured.
  • Example 9 For the electrode of Example 9 obtained in this way, a mixed solution was prepared so that ethylene carbonate, dimethyl carbonate, and sebaconitrile were in a mass ratio of 25:25:50, and further LiTFSI was dissolved so as to be 1 mol / L. Using the solution as an electrolytic solution, the potential-current curve was measured. For comparison, a potential-current curve was also measured for an aluminum electrode that had not been subjected to any surface treatment.
  • the electrode of Example 9 had a potential window at a level equivalent to that of the electrode of Example 8 in which a conductive diamond-like carbon film having no defect was formed on the titanium substrate.
  • a corrosion current suddenly flowed out from around 4.1 V (vs Li / Li + ).
  • Example 9 also has excellent corrosion resistance and an electrode having a wide potential window, similar to Example 8 (that is, an electrode formed with a conductive diamond-like carbon film having no defects in aluminum). It is.
  • glassy carbon, platinum, or gold is used as a film forming material instead of the conductive diamond-like material having defects in the ninth embodiment, the same degree as glassy carbon, platinum, or gold as the film forming material is used. Potential window.
  • a lithium ion battery can be manufactured using the current collector of the embodiment described above. That is, as shown in FIG. 21, a positive electrode 37 containing a positive electrode active material and a negative electrode 38 made of carbon or the like are disposed on both sides with a separator 36 sandwiched between a battery container 35 made of stainless steel or the like. Further, a current collector 39 based on aluminum is brought into contact with the positive electrode 37, and one end of the current collector 39 is protruded from the battery container 35. Further, a current collector 40 based on nickel or titanium is brought into contact with the negative electrode 38, and one end of the current collector 40 is protruded from the battery container 5.
  • a conductive diamond-like carbon film is formed on a base material, and defects of the film made of conductive diamond-like carbon, glassy carbon, Pt, and Au are made of aluminum, nickel, or titanium. Since it is covered with a passive film made of a fluorine compound, it has conductivity and is extremely excellent in corrosion resistance.
  • the passive film differs depending on the electrolyte and solvent used, but is formed of one or a composite of fluorine compounds, oxygen compounds, nitrogen compounds, carbon compounds and phosphorus compounds.
  • Example 1 In Example 1, a solvent in which adiponitrile, ethylene carbonate (EC), and dimethyl carbonate (DMC) were mixed at a volume ratio of 50:25:25 was used as the organic solvent, and LiPF 6 ( Lithium hexafluorophosphate) was dissolved at 0.05 mol / L to obtain an electrolyte for a lithium ion battery.
  • a solvent in which adiponitrile, ethylene carbonate (EC), and dimethyl carbonate (DMC) were mixed at a volume ratio of 50:25:25 was used as the organic solvent, and LiPF 6 ( Lithium hexafluorophosphate) was dissolved at 0.05 mol / L to obtain an electrolyte for a lithium ion battery.
  • LiPF 6 Lithium hexafluorophosphate
  • Comparative Example 1 In Comparative Example 1, a mixed solvent of 50% by volume of ethylene carbonate and 50% by volume of dimethyl carbonate was used as the organic solvent, and LiPF 6 was dissolved as a lithium salt at a concentration of 1 mol / L. did.
  • the types of nitriles used in each example are as follows.
  • Example 1 Adiponitrile NC (CH 2 ) 4 CN
  • Example 2 Succinonitrile NC (CH 2 ) 2 CN
  • Example 3 Sevacononitrile NC (CH 2 ) 8 CN
  • Example 4 Dodecanedinitrile NC (CH 2 ) 10 CN
  • Example 5 2-Methylglutaronitrile NCCH (CH 3 ) CH 2 CH 2 CN
  • Example 7 3-Methoxypropionitrile CH 3 —O—CH 2 CH 2 CN
  • Example 8 Methyl cyanoacetate NCCH 2 COOCH 3
  • Example 9 cyanoacetate butyl NCCH 2 COO (CH 2) 3 CH 3
  • the potential window of the electrolytic solution of Example 1 was 6.9 V with respect to the Li potential (Li / Li + ) (the judgment criterion of the potential window was 50 ⁇ A / cm 2, and so on). It became.
  • the potential window of Comparative Example 1 using a mixed solvent of ethylene carbonate and dimethyl carbonate is 5.2 V as shown in FIG. 246, and the potential window of the electrolytic solution of Example 1 is Comparative Example 1. Compared to the electrolyte solution of, it was found that it spreads greatly on the positive side.
  • Example 1 when the electrolytic solution of Example 1 is used, a high potential redox positive electrode active material that exists in a region where the potential for charging exceeds 5.2 V can be used as the positive electrode active material of the lithium ion battery. Thus, a lithium ion battery having high electromotive force and energy density and large capacity can be obtained.
  • the organic solvent undergoes electrolysis even at the redox potential of Li 2 CoPO 4 F or Li 2 NiPO 4 F, and these positive electrode oxidizing substances cannot be used. If the electrolytic solution of Example 1 is used, not only Li 2 CoPO 4 F or Li 2 NiPO 4 F can be used as the positive electrode active material, but also LiCoPO 4 , LiNiPO 4, etc. can be used.
  • the types of nitriles used in each example are as follows.
  • Example 10 Glutaronitrile NC (CH 2 ) 3 CN
  • Example 11 sebaconitrile NC (CH 2) 8 CN
  • Example 12 Dodecanedinitrile NC (CH 2 ) 10 CN
  • Example 13 2-Methylglutaronitrile NCCH (CH 3 ) CH 2 CH 2 CN
  • Example 14 oxy dipropionate nitrile NCCH 2 CH 2 -O-CH 2 CH 2 CN
  • Example 15 3-Methoxy-propionitrile CH 3 -O-CH 2 CH 2 CN
  • Example 16 methyl cyanoacetate NCCH 2 COOCH 3
  • Example 17 cyanoacetate butyl NCCH 2 COO (CH 2) 3 CH 3
  • the types of nitriles used in each example are as follows.
  • Example 18 Glutaronitrile NC (CH 2 ) 3 CN
  • Example 19 adiponitrile NC (CH 2) 4 CN
  • Example 20 sebaconitrile NC (CH 2) 8 CN
  • Example 21 dodecane dinitrile NC (CH 2) 10 CN
  • Example 22 2-methylglutaronitrile NCCH (CH 3) CH 2 CH 2 CN
  • Example 23 oxy dipropionate nitrile NCCH 2 CH 2 -O-CH 2 CH 2 CN
  • Example 24 methyl cyanoacetate NCCH 2 COOCH 3
  • Example 25 cyanoacetate butyl NCCH 2 COO (CH 2) 3 CH 3
  • the types of nitriles used in each example are as follows.
  • Example 26 glutaronitrile NC (CH 2) 3 CN
  • Example 27 sebaconitrile NC (CH 2) 8 CN
  • Example 28 Dodecanedinitrile NC (CH 2 ) 10 CN
  • Example 29 2-methylglutaronitrile NCCH (CH 3) CH 2 CH 2 CN
  • Example 30 oxy dipropionate nitrile NCCH 2 CH 2 -O-CH 2 CH 2 CN
  • Example 31 methyl cyanoacetate NCCH 2 COOCH 3
  • Comparative Example 4 LiPF 6 as a lithium salt was dissolved in dimethyl carbonate as an organic solvent so as to be 1 mol / L to obtain an electrolytic solution for a lithium ion battery.
  • Example 30 using a chain ether nitrile compound in which a nitrile group was bonded to both ends of the chain ether compound, the potential window was greatly expanded, and in Example 31 using cyanoacetate, the potential window was expanded.
  • the types of nitriles used in each example are as follows.
  • Example 32 sebaconitrile NC (CH 2) 8 CN
  • Comparative Example 5 an electrolyte solution for a lithium ion battery was prepared by dissolving LiPF 6 as a lithium salt in propylene carbonate as an organic solvent so as to be 1 mol / L.
  • the types of nitriles used in each example are as follows.
  • Example 34 glutaronitrile NC (CH 2) 3 CN
  • Example 36 dodecane dinitrile NC (CH 2) 10 CN
  • Comparative Example 6 a lithium ion battery electrolyte solution was prepared by dissolving LiPF 6 as a lithium salt in ⁇ -butyrolactone as an organic solvent so as to have a concentration of 0.1 mol / L.
  • the types of nitriles used in each example are as follows.
  • Example 37 sebaconitrile NC (CH 2) 8 CN
  • Example 38 2-methylglutaronitrile NCCH (CH 3) CH 2 CH 2 CN
  • Example 39 oxy dipropionate nitrile NCCH 2 CH 2 -O-CH 2 CH 2 CN
  • the solvent was stably present up to a high potential by adding a chain saturated hydrocarbon dinitrile compound having nitrile groups bonded to both ends of the chain saturated hydrocarbon compound. Furthermore, it was found that, among the chain-type saturated hydrocarbon dinitrile compounds, not only in Example 37, which is a linear molecule, but also in Example 38 having branches, the potential window greatly spreads in the positive and negative directions. Further, in Example 39 using a chain ether nitrile compound in which a nitrile group was bonded to both ends of the chain ether compound, the potential window was greatly widened in the positive and negative directions.
  • the types of electrolyte used in each example are as follows.
  • Example 40 LiPF 6 Example 41 LiTFSI Example 42 LiTFSI Example 43 LiBF 4
  • Example 45 In Example 45, a solvent in which sebacononitrile, ethylene carbonate (EC), and dimethyl carbonate (DMC) were mixed at a volume ratio of 50:25:25 was used as the organic solvent, and LiPF 6 ( Lithium hexafluorophosphate) was dissolved at 0.05 mol / L and LiTFSI (lithium bis (trifluoromethanesulfonyl) imide) was dissolved at 1.0 mol / L to obtain an electrolyte for a lithium ion battery.
  • LiPF 6 Lithium hexafluorophosphate
  • LiTFSI lithium bis (trifluoromethanesulfonyl) imide
  • Example 46 In Example 46, a solvent in which butyl cyanoacetate, ethylene carbonate (EC), and dimethyl carbonate (DMC) were mixed at a volume ratio of 50:25:25 as an organic solvent, and LiTFSI as a lithium salt was used. (Lithium bis (trifluoromethanesulfonyl) imide) was dissolved at 1.0 mol / L to obtain an electrolytic solution for a lithium ion battery.
  • LiTFSI Lithium bis (trifluoromethanesulfonyl) imide
  • Example 47 In Example 47, a solvent obtained by mixing butyl cyanoacetate, ethylene carbonate (EC), and dimethyl carbonate (DMC) in a volume ratio of 50:25:25 as an organic solvent, and LiBF as a lithium salt was used. 4 (lithium tetrafluoroborate) was dissolved at 1.0 mol / L to obtain an electrolyte for a lithium ion battery.
  • EC ethylene carbonate
  • DMC dimethyl carbonate
  • the electrode potential at a predetermined current density obtained from the potential-current curve is shown in Table 2. From this table, a chain saturated hydrocarbon dinitrile compound having a nitrile group bonded to both ends of the chain saturated hydrocarbon compound, a chain ether nitrile compound having a nitrile group bonded to at least one of the ends of the chain ether compound, and cyano It can be seen that the potential window widens in the positive direction when at least one nitrile compound of acetic acid ester and at least one of cyclic carbonate, cyclic ester and chain carbonate are contained.
  • the preferable amount of sebacononitrile added as an electrolyte for a lithium battery is 1% by volume or more and less than 100% by volume, more preferably 5% by volume or more and less than 90% by volume, and most preferably 30% by volume or more and 70% by volume. %.
  • the potential-current curve for the electrolyte solution of the example it was found that the potential window greatly expanded in the positive direction by adding the nitrile compound to the organic solvent.
  • the potential-current curve of the above example after scanning several times on the positive side and the negative side, the potential is swept at a rate of 5 mV / sec from the natural potential in the positive direction or the negative direction. And the potential-current curve is measured. In the potential scan several times before this measurement, the potential window spreads after the second time. Therefore, by sweeping the potential in the positive direction in the electrolytic solution of the present invention, an electrode having a wide potential window is formed. It can be seen that it can be manufactured.
  • Electrode processing method (2) The method for treating an electrode according to (1), wherein the high potential is more than 5.2 V, preferably 6.0 V or more with respect to the (Li / Li + ) reference electrode.
  • the nitrile compound is a chain saturated hydrocarbon dinitrile compound in which a nitrile group is bonded to both ends of a chain saturated hydrocarbon compound, or a chain ether nitrile in which a nitrile group is bonded to at least one end of a chain ether compound.
  • At least one of a compound and a cyanoacetic acid ester, The electrode processing method according to (2), wherein the electrode is made of carbon.
  • a chain saturated hydrocarbon dinitrile compound having a nitrile group bonded to both ends of a chain saturated hydrocarbon compound, a chain ether nitrile compound having a nitrile group bonded to at least one terminal of the chain ether compound, and cyanoacetic acid An immersion step of immersing the electrode in an organic solvent containing a nitrile compound that is at least one of the esters; And a positive voltage applying step of applying a positive voltage to the electrode after the immersion step.
  • a potentiogalvanostat was used for the measurement.
  • (Ag / Ag + ) was used as the reference electrode.
  • the potential was swept from the natural potential in the positive direction or the negative direction at a speed of 0.5 mV / sec, and the potential-current curve was measured.
  • the present invention is applied to a lithium ion battery.
  • the lithium ion battery includes an electrolytic solution, a positive electrode, a negative electrode, a separator, and a case.
  • the electrolytic solution contains a Li salt (electrolyte) and an organic solvent.
  • a Li salt a general Li salt for a Li ion battery can be used.
  • LiPF 6 lithium hexafluorophosphate
  • LiBF 4 lithium tetrafluoroborate
  • LiTFSI lithium bis (trifluoromethanesulfonyl) imide
  • LiTFS lithium trifluoromethanesulfonate
  • LiBETI lithium bis ( Pentafluoroethanesulfonyl) imide
  • LiPF 6 for those redox potential of the positive electrode is more than 4.5V, it is preferable to use LiPF 6, and / or LiBF 4. In the case of using a LiTFSI and LiTFS and LiBETI, it is preferable to add LiPF 6 or LiBF 4.
  • organic solvent a general solvent used for a Li ion battery can be adopted.
  • Such an organic solvent is preferably one or more selected from cyclic carbonates, cyclic carboxylic acid esters and chain carbonates. More preferably, a cyclic carbonate and a chain carbonate are used in combination. Specifically, it is particularly preferable to use ethylene carbonate and dimethyl carbonate in combination. The blending ratio of both is not particularly limited.
  • cyclic carboxylic acid ester ⁇ -butyrolactone can be used.
  • a nitrile compound can be used as an organic solvent.
  • nitrile compound a chain saturated hydrocarbon dinitrile compound in which a nitrile group is bonded to both ends of a chain saturated hydrocarbon compound, a chain ether in which a nitrile group is bonded to at least one terminal of a chain ether compound. Mention may be made of at least one nitrile compound among nitrile compounds and cyanoacetic acid esters.
  • Examples of the chain saturated hydrocarbon dinitrile compound in which nitrile groups are bonded to both ends of the chain saturated hydrocarbon compound include succinonitrile NC (CH 2 ) 2 CN, glutaronitrile NC (CH 2 ) 3 CN, adiponitrile
  • succinonitrile NC (CH 2 ) 2 CN glutaronitrile NC (CH 2 ) 3 CN
  • adiponitrile In addition to linear dinitrile compounds such as NC (CH 2 ) 4 CN, sebaconitrile NC (CH 2 ) 8 CN, dodecanedinitrile NC (CH 2 ) 10 CN, 2-methylglutaronitrile NCCH (CH 3 ) CH 2 CH 2 CN may have a branched as such.
  • These chain saturated hydrocarbon dinitrile compounds are not particularly limited in carbon number, but are preferably 20 or less. More preferably, it is 7-12.
  • Examples of the chain ether nitrile compound in which a nitrile group is bonded to at least one end of the chain ether compound include oxydipropionitrile NCCH 2 CH 2 —O—CH 2 CH 2 CN and 3-methoxypropionitrile CH 3 -O-CH 2 CH 2 CN and the like can be mentioned. These chain ether nitrile compounds are not particularly limited in carbon number, but are preferably 20 or less.
  • Examples of cyanoacetic acid esters include methyl cyanoacetate, ethyl cyanoacetate, propyl cyanoacetate, and butyl cyanoacetate. These cyanoacetic acid esters are not particularly limited in carbon number, but are preferably 20 or less.
  • nitrile compounds have the effect of expanding the potential window particularly in the positive direction in the electrolytic solution.
  • a dinitrile compound is preferable from the viewpoint of the action of expanding the potential window.
  • the use of sebacononitrile is more preferable.
  • a nitrile compound has high viscosity, it is preferable to use together with the above-mentioned chain carbonate ester, cyclic carbonate ester, and / or cyclic carboxylic acid ester. More preferably, a nitrile compound, a chain carbonate ester and a cyclic carbonate ester are used in combination. Dimethyl carbonate can be employed as the chain carbonate, and ethylene carbonate can be employed as the cyclic carbonate.
  • the blending ratio of the nitrile compound in the whole organic solvent is preferably 1 to 90% by volume. More preferably, it is 5 to 70% by volume, and still more preferably 10 to 50% by volume.
  • the concentration of the Li salt is 0.01 mol / L or more and is lower than the saturated state.
  • concentration of the Li salt is less than 0.01 mol / L, ion conduction by Li ions is reduced, and the electric resistance of the electrolytic solution is increased, which is not preferable.
  • exceeding the saturation state is not preferable because the dissolved Li salt precipitates due to environmental changes such as temperature.
  • the positive electrode includes a positive electrode active material and a current collector.
  • the positive electrode active material refers to “a material in which lithium is inserted / extracted in the crystal structure at a higher potential than the negative electrode, and oxidation / reduction is performed accordingly”. Examples of the positive electrode active material include (1) an oxide system, (2) a phosphate system having an olivine type crystal structure, and (3) an olivine fluoride system.
  • Li, Mg, Al, Ti, V, Mn, Fe, Co, Ni, Cu, Zn, Zr, Nb, and Mo can be used.
  • 1-2 Characteristics A general discharge potential of this positive electrode active material is less than 5 V (vs Li / Li + ).
  • LiNi 0.5 Mn 1.5 O 4 partially substituted with Ni in the LiMn 2 O 4 system has a discharge potential of 4.7 V, and takes into account overvoltage when performing rapid charging, and 5 V May require a charging voltage exceeding.
  • LiCoMnO 4 starts with a discharge voltage of about 5.2V, the charge voltage also exceeds 5V.
  • oxide systems generally decompose at less than 300 ° C., and have a relatively large exothermic reaction as oxygen is generated. Therefore, a control circuit that does not cause overcharging is required.
  • the dopant is not particularly limited as long as the electrochemical characteristics can be changed in the oxidation-reduction reaction.
  • one or more of Mg, Al, Ti, V, Mn, Fe, Co, Ni, Cu, Zn, Zr, Nb, and Mo can be used (see JP 2008-130525 A).
  • 2-2 Characteristics The oxidation-reduction potential of this positive electrode active material has been attracting attention because it has a low safety exothermic reaction at 300 ° C. and high safety because it does not generate oxygen.
  • the LiCoPO 4 system has a discharge potential of about 4.8 V, and an electrolyte having a withstand voltage of 5 V or more is required for rapid charging. It is suggested that the discharge potential of LiNiPO 4 is 5.2 V (vs Li / Li + ).
  • the oxidation-reduction potential of this positive electrode active material is different from that of the above-mentioned oxide type, as in the olivine type. Since decomposition is less than 300 ° C., the exothermic reaction is small and oxygen is not generated. The effect of battery ignition is considered to be small, and is attracting attention in terms of safety. Further, the electric capacity density (mAh / g) of the battery can be made higher than that of the phosphate system (see Japanese Patent Application Laid-Open No. 2003-229126).
  • the Li 2 CoPO 4 F system has an average discharge potential of about 4.8 V, and an electrolytic solution having a withstand voltage of 5 V or more is required for rapid charging. Further, the discharge potential of the Li 2 NiPO 4 F system is about 5.2 V (vs Li / Li + ), and an electrolytic solution having a withstand voltage at 5 V or more is required.
  • lithium-free FeF 3 a conjugated polymer using an organic conductive material, a chevrel phase compound, or the like can also be used.
  • transition metal chalcogenides, vanadium oxides and lithium salts thereof, niobium oxides and lithium salts thereof, and a plurality of different positive electrode active materials may be used in combination.
  • the average particle diameter of the positive electrode active material particles is not particularly limited, but is preferably 10 nm to 30 ⁇ m.
  • the positive electrode current collector is a conductive substrate carrying a positive electrode active material.
  • the molding material for the current collector of the positive electrode is required to be stable during charging.
  • a material excellent in corrosion resistance when using a phosphate-based and olivine fluoride-based positive electrode active material having an olivine-type crystal structure with a high redox potential, it is preferable to use a material excellent in corrosion resistance.
  • austenitic stainless steel, Ni, Al, Ti, or the like can be used, but it is preferable to select them appropriately in consideration of the operating potential of the positive electrode active material to be used.
  • LiPF 6 when used as the electrolyte, it can be used even at 6 V with respect to the Li / Li + electrode.
  • SUS304 when LiBF 4 is used as the electrolyte, SUS304 is 5.8 V or less with respect to the Li / Li + electrode. It can be used only when charge / discharge is possible.
  • LiTFSI when used as the electrolyte, it is preferable that LiPF 6 coexists in order to form a corrosion-resistant film on the surface of the positive electrode current collector.
  • LiBETI and LiTFS are the same as in LiTFSI.
  • a conductive metal material such as Al coated with conductive DLC (diamond-like carbon) by a well-known method can be used as a current collector.
  • the electrolyte is a lithium salt such as LiBF 4 or LiPF 6 that easily forms a fluoride film
  • a thick fluoride film is formed on the aluminum and the corrosion resistance is improved, but the electronic conductivity is lowered, and consequently The increase in output accompanying the increase in ohmic overvoltage is impeded.
  • the conductive metal material such as Al is coated with the conductive DLC, the fluoride film is generated only in a very small area of the defective portion of the conductive DLC. For this reason, even if the voltage is increased, the decrease in electron conductivity is negligible, and it is possible to prevent the decrease in output due to the increased voltage, which is a concern.
  • the conductive diamond-like carbon is carbon having an amorphous structure in which both diamond bonds (SP 3 hybrid orbital bonds between carbons) and graphite bonds (SP 2 hybrid orbital bonds between carbons) are mixed. Among them, the one whose conductivity is 1000 ⁇ cm or less. However, in addition to the amorphous structure, those having a phase composed of a crystal structure partially composed of a graphite structure (that is, a hexagonal crystal structure composed of SP 2 hybrid orbital bonds) and thereby exhibiting conductivity are also included. . Diamond-like carbon having properties intermediate between graphite and diamond adjusts the conductivity by adjusting the ratio of SP 2 hybrid orbital bonds and SP 3 hybrid orbital bonds of the carbon atoms constituting diamond-like carbon during film formation. be able to. Of course, you may coat
  • the shape and structure of the current collector can be arbitrarily designed according to the structure of the positive electrode active material and the battery.
  • the positive electrode for a lithium ion battery performs an immersion treatment step of immersing the positive electrode in a pretreatment electrolytic solution in which a lithium salt is dissolved in an organic solvent containing 1% by volume or more of a nitrile compound before being incorporated in the lithium ion battery, Further, a positive voltage processing step for applying a positive voltage to the electrode is performed.
  • the electrode thus pretreated has a wide potential window even when used in an electrolyte solution containing no nitrile compound or in a lithium ion battery using an electrolyte solution with a small amount of nitrile compound added. It becomes difficult to disassemble (see Japanese Patent Application No. 2009-180007).
  • the reason why the electrode has such a wide potential window is presumed to be that a corrosion-resistant film containing nitrogen as a component is formed on the electrode.
  • the negative electrode includes a negative electrode active material and a current collector.
  • the negative electrode active material refers to “a material in which lithium is inserted / extracted in the crystal structure at a lower potential than the positive electrode, and oxidation / reduction is performed accordingly”.
  • Examples of the negative electrode active material include various carbon materials such as artificial graphite, natural graphite, and hard carbon, lithium titanate (Li 4 Ti 5 O 12 ), H 2 Ti 12 O 25 , H 2 Ti 6 O 13 , Fe 2 O 3 etc. are mentioned.
  • the composite material which mixed these suitably can also be mentioned.
  • Si fine particles and Si thin films and fine particles and thin films in which these Si are Si-based alloys such as Si—Ni, Si—Cu, Si—Nb, Si—Zn, and Si—Sn.
  • composites such as SiO oxide, Si—SiO 2 composite, Si—SiO 2 —carbon, and the like can be given.
  • the current collector for the negative electrode can be formed of a general-purpose conductive metal material, Cu, Al, Ni, Ti, austenitic stainless steel, or the like.
  • a nitrile compound is used for the electrolytic solution (including combined use with other organic solvents)
  • it is necessary to select appropriately according to the Li salt in the electrolytic solution that is, when LiPF 6 or LiBF 4 is used as the electrolyte, austenitic stainless steel, Ni, Al, Ti, or the like can be used.
  • Electroconductive member for positive electrode Some positive electrode active materials have low electrical conductivity. Therefore, it is preferable to provide a sufficient electron conduction path between the positive electrode active material and the current collector by interposing a conductive electron conduction member.
  • the electron conducting member for the positive electrode there are a material called a powdery conductive additive having electron conductivity and a plate-like material having electron conductivity.
  • a powdery conductive additive having electron conductivity
  • a plate-like material having electron conductivity there are a material called a powdery conductive additive having electron conductivity and a plate-like material having electron conductivity.
  • at least one of conductive diamond-like carbon powder and glassy carbon powder is used, but other positive electrode electronic conductive members may be used in combination.
  • the shape of the electron conducting member is not particularly limited as long as an electron conduction path can be formed between the positive electrode active material and the current collector.
  • Conductive powders such as carbon black and graphite powder can be used.
  • Diamond-like carbon and glassy carbon have a much wider potential window than carbon black and graphite, and are excellent in corrosion resistance when a high potential is applied, and therefore can be suitably used.
  • metal fine particles are supported on these conductive assistants. Examples of the metal fine particles include Pt, Au, Ni and the like. These may be used alone or an alloy thereof.
  • a conductive thin plate in which the positive electrode active material is embedded can be used as the electron conductive material.
  • Electroconductive member for negative electrode The thing similar to the electron conductive member for positive electrodes can be used.
  • the separator is immersed in the electrolytic solution, separates the positive electrode and the negative electrode, prevents a short circuit therebetween, and allows the passage of Li ions.
  • separators include porous films made of polyolefin resins such as polyethylene and polypropylene.
  • the case is formed of a material having corrosion resistance against the electrolytic solution.
  • the shape can be arbitrarily designed according to the intended use of the battery.
  • a base material made of austenitic stainless steel a case made of Ti, Ni and / or Al can be used.
  • the case also serves as a current collector or is electrically coupled to the current collector, the case is formed of the same or the same material as the current collector forming material of each electrode.

Abstract

A positive electrode for a secondary battery according to the first invention is characterized by containing either a conductive diamond-like carbon powder or a glassy carbon powder, as a conductive assistant.  A positive electrode for a secondary battery according to the second invention is characterized in that conductive diamond-like carbon is adhered to particles, which are composed of a positive electrode active material, by dry plating. A battery according to the third invention comprises an organic solvent and a collector wherein a conductive corrosion-resistant coating film, which is composed of one or more materials selected from among conductive diamond-like carbon, glassy carbon, gold and platinum, is formed on the surface of a collector base which is mainly composed of aluminum, nickel or titanium, or a collector base which is composed of an austenitic stainless steel.  The battery is characterized in that the organic solvent contains a nitrile compound such as a chain saturated hydrocarbon dinitrile compound wherein a nitrile group is bonded to both ends of a chain saturated hydrocarbon compound.

Description

二次電池用正極及びそれを用いた二次電池、並びに、集電体及びそれを用いた電池Positive electrode for secondary battery, secondary battery using the same, current collector and battery using the same
　第１発明は二次電池用正極及び二次電池に関し、Ｌｉ２ＮｉＰＯ４Ｆ、ＬｉＮｉＰＯ４、ＬｉＣｏＰＯ４、Ｌｉ２ＣｏＰＯ４Ｆ等、高い電位で充電反応が行われる正極活物質を利用した二次電池として好適に用いることができる。
　また、第２発明は二次電池用正極及び二次電池に関し、Ｌｉ２ＮｉＰＯ４Ｆ、ＬｉＮｉＰＯ４、ＬｉＣｏＰＯ４、Ｌｉ２ＣｏＰＯ４Ｆ等、高い電位で充電反応が行われる正極活物質を利用した二次電池として好適に用いることができる。
　さらに第３発明は、リチウムイオン電池やナトリウムイオン電池、電気二重層キャパシター、リチウムイオンキャパシター等に用いることのできる、耐食性に優れた集電体及び電池に関する。 The first invention relates to a positive electrode and a secondary battery for a secondary battery, a secondary utilizing Li 2 NiPO 4 F, LiNiPO 4 , LiCoPO 4, Li 2 CoPO 4 F or the like, a positive electrode active material charging reaction at a high potential is performed following It can be suitably used as a battery.
The second invention relates to a positive electrode and a secondary battery for a secondary battery, using a positive electrode active material Li 2 NiPO 4 F, LiNiPO 4 , LiCoPO 4, Li 2 CoPO 4 F or the like, the charging reaction at a high potential is performed It can be suitably used as a secondary battery.
Furthermore, the third invention relates to a current collector and a battery excellent in corrosion resistance that can be used for a lithium ion battery, a sodium ion battery, an electric double layer capacitor, a lithium ion capacitor, and the like.
　従来、二次電池の正極活物質にカーボン粉を混合し、正極に必要な電子伝導性を付与することが行なわれている。例えば、リチウムイオン電池用の正極活物質として、コバルト酸リチウム（ＬｉＣｏＯ2）、ニッケル酸リチウム（ＬｉＮｉＯ2）、これらの固溶体、マンガン酸リチウム（ＬｉＭｎ2Ｏ4）等が用いられており、これら正極材料に導電助剤としてのカーボンを混合して正極に必要な電子伝導性を付与し、さらにはポリテトラフルオロエチレン（ＰＴＦＥ）やポリフッ化ビニリデン（ＰＶｄＦ）等のフッ素樹脂を結着剤として用いることにより正極が成形されている。 Conventionally, carbon powder is mixed with a positive electrode active material of a secondary battery to impart necessary electron conductivity to the positive electrode. For example, lithium cobaltate (LiCoO 2 ), lithium nickelate (LiNiO 2 ), solid solutions thereof, lithium manganate (LiMn 2 O 4 ), and the like are used as positive electrode active materials for lithium ion batteries. Carbon as a conductive additive is mixed with the material to provide the necessary electronic conductivity for the positive electrode, and a fluororesin such as polytetrafluoroethylene (PTFE) or polyvinylidene fluoride (PVdF) is used as a binder. Thus, the positive electrode is formed.
　そして、さらなる大出力化及び高速充電の要請に応えるため、電極を作製する時に原料を炭化したり、電極活物質と導電助剤と溶媒とを湿式法により混合粉砕した後、溶媒を除去したり（特許文献１）して、電子伝導性を向上させることが行なわれている。また、金属で表面を被覆した高分子材料を導電助剤として用いたり（特許文献２）、活物質層に導電助剤として金属粒子を含ませたり（特許文献３）して、電子伝導性を向上させることも提案されている。 In order to meet the demand for higher output and higher speed charging, the raw material is carbonized when manufacturing the electrode, or the electrode active material, the conductive additive and the solvent are mixed and pulverized by a wet method, and then the solvent is removed. (Patent Document 1) and improving the electronic conductivity. Moreover, the polymer material which coat | covered the surface with the metal is used as a conductive support agent (patent document 2), or a metal particle is included in the active material layer as a conductive assistant agent (patent document 3). Improvements have also been proposed.
　また、電池等の電気化学セルと外部との電子の出し入れを行なうために、導電性を有する集電体が電極に接触するようにして用いられている。例えば、リチウムイオン電池では、正極材料に接触する集電体としてアルミニウムからなる集電体、負極材料に接触する集電体としてニッケル等が用いられており、これらの集電体を介して充電や放電が行なわれる。また、高分子電解質燃料電池においては、金属からなるセパレータが集電体として機能し、外部へ電流を取り出している。 Also, a conductive current collector is used in contact with the electrode in order to take in and out electrons from an electrochemical cell such as a battery and the outside. For example, in a lithium ion battery, a current collector made of aluminum is used as a current collector in contact with a positive electrode material, and nickel or the like is used as a current collector in contact with a negative electrode material. Discharging occurs. In a polymer electrolyte fuel cell, a separator made of metal functions as a current collector and takes out current to the outside.
　集電体は、過酷な腐食環境下に置かれることが多く（特に電気化学的な酸化反応が生じる正極（カソード）側の集電体においては厳しい腐食環境となる）、耐食性を有することが要求される。こうした集電体の耐食性の要求に応えるため、金属からなる集電体の表面に導電性を有する耐食性皮膜を形成することが行なわれている。例えば特許文献４では、アルミニウムからなる基板に導電性グラファイトからなる皮膜をスパッタリングで形成することによって導電性を有しつつ耐食性を高め、これを燃料電池用のセパレータとして用いることが提案されている。 Current collectors are often placed in harsh corrosive environments (especially the current collector on the positive electrode (cathode) side where an electrochemical oxidation reaction takes place), and must have corrosion resistance. Is done. In order to meet the corrosion resistance requirement of the current collector, a corrosion-resistant film having conductivity is formed on the surface of the current collector made of metal. For example, Patent Document 4 proposes that a coating made of conductive graphite is formed on a substrate made of aluminum by sputtering to increase the corrosion resistance while having conductivity, and this is used as a separator for a fuel cell.
特開２００８－１４７０２４号公報JP 2008-147024 A 特開２００７－３１１０５７号公報JP 2007-311057 A 特開２００６－１６４８２３号公報JP 2006-164823 A 特開２００４－２３５０９１号公報JP 2004-235091 A
｛第１発明｝
　しかし、上記のＬｉ２ＮｉＰＯ４Ｆ、ＬｉＮｉＰＯ４、ＬｉＣｏＰＯ４、Ｌｉ２ＣｏＰＯ４Ｆ等の高い電位で充電反応が行われる正極活物質では、導電助剤としてこれらの正極活物質に添加したグラファイト粉等が、充電時の高い電位においてグラファイトが酸化されてしまったり、グラファイト粉上での電気化学反応によって溶媒が分解されてしまったりするという問題があった。 {First invention}
However, the above Li 2 NiPO 4 F, LiNiPO 4 , LiCoPO 4, Li 2 CoPO 4 The positive electrode active material charging reaction at a high potential of F or the like is performed, a graphite powder was added to these positive electrode active material as a conductive additive However, there is a problem that the graphite is oxidized at a high potential during charging or the solvent is decomposed by an electrochemical reaction on the graphite powder.
　第１発明は上記諸点に鑑みてなされたものであり、高い電位で充電反応が行われる、エネルギー密度の高い正極活物質を有効に活用することができる二次電池用正極を提供することを目的とする。 The first invention has been made in view of the above points, and an object thereof is to provide a positive electrode for a secondary battery in which a charging reaction is performed at a high potential and a positive electrode active material having a high energy density can be effectively used. And
　第１発明の二次電池用正極は、正極活物質と導電助剤とが含まれている二次電池用正極において、前記導電助剤には導電性ダイヤモンドライクカーボン粉及びグラシーカーボン粉の少なくとも１種が含まれていることを特徴とする。 A positive electrode for a secondary battery according to a first aspect of the present invention is the positive electrode for a secondary battery containing a positive electrode active material and a conductive additive, wherein the conductive additive includes at least conductive diamond-like carbon powder and glassy carbon powder. One type is included.
　第１発明の二次電池用正極では、導電助剤に導電性ダイヤモンドライクカーボン粉及びグラシーカーボン粉の少なくとも１種が含まれている。本発明者らの試験結果によれば、ダイヤモンドライクカーボンやグラシーカーボンは、グラファイトよりも広い電位窓を有しており、高い電位において安定であり、溶媒を分解するおそれも少なく、電子伝導性も優れている。このため、正極活物質と導電助剤とが混合されている二次電池用正極における導電助剤として用いれば、正極に必要な高い導電性を確保でき、充電時の高い電位において酸化されてしまったり、溶媒が分解したりしてしまうことを防ぐことができる。このため、ひいては高い電位で充電反応が行われ、エネルギー密度の高い正極活物質を有効に活用することができる。 In the positive electrode for secondary battery of the first invention, the conductive assistant contains at least one of conductive diamond-like carbon powder and glassy carbon powder. According to the test results of the present inventors, diamond-like carbon and glassy carbon have a wider potential window than graphite, are stable at a high potential, are less likely to decompose the solvent, and have electron conductivity. Is also excellent. For this reason, when used as a conductive additive in a positive electrode for a secondary battery in which a positive electrode active material and a conductive additive are mixed, the high conductivity necessary for the positive electrode can be secured and it is not oxidized at a high potential during charging. Or the solvent can be prevented from decomposing. Therefore, the charging reaction is performed at a high potential, and the positive electrode active material having a high energy density can be effectively used.
　ここで、導電性ダイヤモンドライクカーボンとは、ダイヤモンド結合（炭素同士のＳＰ３混成軌道結合）とグラファイト結合（炭素同士のＳＰ２混成軌道結合）の両方の結合が混在しているアモルファス構造をとるカーボンのうち、導電性が１０００Ωcm以下のものをいう。ただし、アモルファス構造以外に、部分的にグラファイト構造からなる結晶構造（すなわちＳＰ２混成軌道結合からなる六方晶系結晶構造）からなる相を有し、これにより導電性が発揮されるものも含まれる。グラファイトとダイヤモンドの中間の性質を有するダイヤモンドライクカーボンは、成膜時にダイヤモンドライクカーボンを構成する炭素原子のＳＰ２混成軌道結合とＳＰ３混成軌道結合の比率を調整することで、導電性を調節することができる。 Here, the conductive diamond-like carbon is carbon having an amorphous structure in which both diamond bonds (SP 3 hybrid orbital bonds between carbons) and graphite bonds (SP 2 hybrid orbital bonds between carbons) are mixed. Among them, the one whose conductivity is 1000 Ωcm or less. However, in addition to the amorphous structure, those having a phase composed of a crystal structure partially composed of a graphite structure (that is, a hexagonal crystal structure composed of SP 2 hybrid orbital bonds) and thereby exhibiting conductivity are also included. . Diamond-like carbon having properties intermediate between graphite and diamond adjusts the conductivity by adjusting the ratio of SP 2 hybrid orbital bonds and SP 3 hybrid orbital bonds of the carbon atoms constituting diamond-like carbon during film formation. be able to.
　第１発明の二次電池用正極に用いられる正極活物質としては、Ｌｉ２ＮｉＰＯ４Ｆ、ＬｉＮｉＰＯ４、ＬｉＣｏＰＯ４及びＬｉ２ＣｏＰＯ４Ｆの少なくとも１種を含むことができる。これらの正極活物質は、高い電位において充電されるため、エネルギー密度が大きいという利点はあるものの、従来のグラファイトからなる導電助剤では酸化されたり、溶媒が分解されたりするおそれがあった。これに対して導電助剤にダイヤモンドライクカーボンやグラシーカーボンを用いる本発明の二次電池用正極では、電位窓が広く、導電助剤の酸化や溶媒の分解がされ難いため、エネルギー密度が大きなこれらの正極活物質の利点を有効に活用できるリチウムイオン電池として、好適に用いることができる。 As the positive electrode active material used in the positive electrode for secondary battery of the first invention, Li 2 NiPO 4 F, it may comprise at least one LiNiPO 4, LiCoPO 4 and Li 2 CoPO 4 F. Since these positive electrode active materials are charged at a high potential, there is an advantage that the energy density is large, but there is a possibility that the conventional conductive assistant made of graphite is oxidized or the solvent is decomposed. On the other hand, in the positive electrode for secondary battery of the present invention using diamond-like carbon or glassy carbon as a conductive assistant, the potential window is wide and the conductive assistant is difficult to be oxidized or decomposed. It can be suitably used as a lithium ion battery that can effectively utilize the advantages of these positive electrode active materials.
　また、発明者らの試験結果によれば、ニトリル化合物を含む電解液は広い電位窓を有するため、Ｌｉ２ＮｉＰＯ４Ｆ、ＬｉＮｉＰＯ４、ＬｉＣｏＰＯ４及びＬｉ２ＣｏＰＯ４Ｆ等の高い電位において充電される正極活物質の充電領域でも安定に存在し、分解に耐えうる。このため、本発明の二次電池用正極用の電解液として好適である。このため、本発明の二次電池は、第１発明の二次電池用正極と、ニトリル化合物を含む電解液と、を備えていることを特徴とするとした。 Further, according to the inventors of the test results, the electrolyte solution containing the nitrile compound is charged in a wide since it has a potential window, Li 2 NiPO 4 F, LiNiPO 4, LiCoPO 4 and Li 2 CoPO 4 F higher potential of such It exists stably in the charged region of the positive electrode active material, and can withstand decomposition. For this reason, it is suitable as an electrolytic solution for the positive electrode for the secondary battery of the present invention. For this reason, the secondary battery of the present invention is characterized by including the positive electrode for the secondary battery of the first invention and an electrolytic solution containing a nitrile compound.
｛第２発明｝
　また、上記のＬｉ２ＮｉＰＯ４Ｆ、ＬｉＮｉＰＯ４、ＬｉＣｏＰＯ４、Ｌｉ２ＣｏＰＯ４Ｆ等の高い電位で充電反応が行われる正極活物質では、導電助剤としてこれらの正極活物質に添加したグラファイト粉等が、充電時の高い電位において酸化されてしまったり、グラファイト粉上での電気化学反応によって溶媒が分解されてしまったりするという問題があった。 {Second invention}
Further, the above Li 2 NiPO 4 F, LiNiPO 4 , LiCoPO 4, Li 2 CoPO 4 The positive electrode active material charging reaction at a high potential of F or the like is performed, a graphite powder was added to these positive electrode active material as a conductive additive And the like may be oxidized at a high potential during charging, or the solvent may be decomposed by an electrochemical reaction on the graphite powder.
　第２発明は上記諸点に鑑みてなされたものであり、高い電位で充電反応が行われる、エネルギー密度の高い正極活物質を有効に活用することができる、二次電池用正極を提供することを目的とする。 The second invention has been made in view of the above points, and provides a positive electrode for a secondary battery capable of effectively utilizing a positive electrode active material having a high energy density in which a charging reaction is performed at a high potential. Objective.
　第２発明の二次電池用正極は、正極活物質からなる粒子の集合体が所定の形状に成形された二次電池用正極において、前記正極活物質からなる粒子には、乾式めっき法によって導電性ダイヤモンドライクカーボンが付着されていることを特徴とする。 The positive electrode for a secondary battery of the second invention is a positive electrode for a secondary battery in which an aggregate of particles made of a positive electrode active material is formed into a predetermined shape. The particles made of the positive electrode active material are electrically conductive by a dry plating method. It is characterized in that a conductive diamond-like carbon is adhered.
　第２発明の二次電池用正極では、正極活物質からなる粒子の集合体が所定の形状に成形されており、正極活物質からなる粒子には、導電性ダイヤモンドライクカーボンが乾式めっき法によって付着されている。このため、導電性ダイヤモンドライクカーボンが導電助剤の役割を果たし、二次電池用正極のために必要な特性である電子伝導性が付与される。しかも、本発明者らの試験結果によれば、ダイヤモンドライクカーボンは、グラファイトよりも広い電位窓を有しており、高い電位において安定であり、溶媒を分解するおそれも少ない。このため、充電時の高い電位においてダイヤモンドライクカーボンが酸化されてしまったり、溶媒が分解したりしてしまうおそれも少ない。このため、ひいては高い電位で充電反応が行われるエネルギー密度の高い正極活物質を、有効に活用することができる。 In the positive electrode for a secondary battery of the second invention, an aggregate of particles made of a positive electrode active material is formed into a predetermined shape, and conductive diamond-like carbon adheres to the particles made of the positive electrode active material by a dry plating method. Has been. For this reason, conductive diamond-like carbon plays the role of a conductive additive, and imparts electronic conductivity, which is a necessary characteristic for the positive electrode for secondary batteries. Moreover, according to the test results of the present inventors, diamond-like carbon has a wider potential window than graphite, is stable at a high potential, and is less likely to decompose the solvent. For this reason, there is little possibility that diamond-like carbon is oxidized or the solvent is decomposed at a high potential during charging. For this reason, the positive electrode active material with a high energy density in which a charging reaction is performed at a high potential can be effectively utilized.
　ここで、導電性ダイヤモンドライクカーボンとは、ダイヤモンド結合（炭素同士のＳＰ３混成軌道結合）とグラファイト結合（炭素同士のＳＰ２混成軌道結合）の両方の結合が混在しているアモルファス構造をとるカーボンのうち、導電性が１０００Ωcm以下のものをいう。ただし、アモルファス構造以外に、部分的にグラファイト構造からなる結晶構造（すなわちＳＰ２混成軌道結合からなる六方晶系結晶構造）からなる相を有し、これにより導電性が発揮されるものも含まれる。グラファイトとダイヤモンドの中間の性質を有するダイヤモンドライクカーボンは、成膜時にダイヤモンドライクカーボンを構成する炭素原子のＳＰ２混成軌道結合とＳＰ３混成軌道結合の比率を調整することで、導電性を調節することができる。 Here, the conductive diamond-like carbon is carbon having an amorphous structure in which both diamond bonds (SP 3 hybrid orbital bonds between carbons) and graphite bonds (SP 2 hybrid orbital bonds between carbons) are mixed. Among them, the one whose conductivity is 1000 Ωcm or less. However, in addition to the amorphous structure, those having a phase composed of a crystal structure partially composed of a graphite structure (that is, a hexagonal crystal structure composed of SP 2 hybrid orbital bonds) and thereby exhibiting conductivity are also included. . Diamond-like carbon having properties intermediate between graphite and diamond adjusts the conductivity by adjusting the ratio of SP 2 hybrid orbital bonds and SP 3 hybrid orbital bonds of the carbon atoms constituting diamond-like carbon during film formation. be able to.
　第２発明の二次電池用正極に用いられる正極活物質としては、Ｌｉ２ＮｉＰＯ４Ｆ、ＬｉＮｉＰＯ４、ＬｉＣｏＰＯ４及びＬｉ２ＣｏＰＯ４Ｆの少なくとも１種を含むことができる。これらの正極活物質は、高い電位において充電されるため、エネルギー密度が大きいという利点はあるものの、従来のグラファイトからなる導電助剤ではグラファイトが酸化されたり、溶媒が分解されたりするおそれがあった。これに対して本発明の二次電池用正極では、高い電位であっても安定なダイヤモンドライクカーボンが導電助剤として働き、電位窓が広くて溶媒の分解もされ難い。このため、エネルギー密度が大きなこれらの正極活物質の利点を有効に活用できるリチウムイオン電池として、好適に用いることができる。 As the positive electrode active material used in the positive electrode for secondary battery of the second invention, Li 2 NiPO 4 F, may comprise at least one LiNiPO 4, LiCoPO 4 and Li 2 CoPO 4 F. Since these positive electrode active materials are charged at a high potential, there is an advantage that the energy density is large. However, there is a possibility that the graphite is oxidized or the solvent is decomposed with the conventional conductive assistant made of graphite. . On the other hand, in the positive electrode for a secondary battery of the present invention, even if the potential is high, stable diamond-like carbon works as a conductive assistant, and the potential window is wide so that the solvent is not easily decomposed. For this reason, it can use suitably as a lithium ion battery which can utilize effectively the advantage of these positive electrode active materials with a large energy density.
　また、発明者らの試験結果によれば、ニトリル化合物を含む電解液は広い電位窓を有するため、Ｌｉ２ＮｉＰＯ４Ｆ、ＬｉＮｉＰＯ４、ＬｉＣｏＰＯ４及びＬｉ２ＣｏＰＯ４Ｆ等の高い電位において充電される正極活物質の充電領域でも安定に存在し、分解に耐えうる。このため、本発明の二次電池用正極用の電解液として好適である。このため、第２発明のの二次電池は、第２発明の二次電池用正極と、ニトリル化合物を含む電解液と、を備えていることを特徴とするとした。 Further, according to the inventors of the test results, the electrolyte solution containing the nitrile compound is charged in a wide since it has a potential window, Li 2 NiPO 4 F, LiNiPO 4, LiCoPO 4 and Li 2 CoPO 4 F higher potential of such It exists stably in the charged region of the positive electrode active material, and can withstand decomposition. For this reason, it is suitable as an electrolytic solution for the positive electrode for the secondary battery of the present invention. For this reason, the secondary battery of the second invention is characterized by comprising the positive electrode for the secondary battery of the second invention and an electrolytic solution containing a nitrile compound.
｛第３発明｝
　電池には様々な電極活物質（例えばリチウムイオン電池におけるＬｉ２ＮｉＰＯ４Ｆ、ＬｉＮｉＰＯ４、ＬｉＣｏＰＯ４、Ｌｉ２ＣｏＰＯ４Ｆ等の正極活物質）が開発されており、電池の起電力がさらに大きくされている。このため、電池の充電時には、各電極に大きな分極電圧が印加されることとなり、電解質塩がＬｉＴＦＳＩやＬｉＢＥＴＩなど、容易にフッ素化合物もしくフッ素と酸素の複合化合物を形成しない塩の場合は、集電材料のアルミニウム上でＬｉの充放電とは関係のない腐食電流が流れてしまうという問題が生じていた。 {Third invention}
Various electrode active material (Li 2 NiPO 4 F in example lithium-ion battery, LiNiPO 4, LiCoPO 4, Li 2 CoPO 4 F positive electrode active material, etc.) to the battery have been developed, further increase the electromotive force of the battery Has been. Therefore, when the battery is charged, a large polarization voltage is applied to each electrode. If the electrolyte salt is a salt that does not easily form a fluorine compound or a complex compound of fluorine and oxygen, such as LiTFSI or LiBETI, There has been a problem that a corrosion current unrelated to charging / discharging of Li flows on aluminum as an electric material.
　一方、電解質塩がＬｉＢＦ４やＬｉＰＦ６など、容易にフッ素化合物もしくはＡｌＯｘ／２Ｆ３－ｘで示されるフッ素と酸素の複合化合物を形成するような塩の場合は（非特許文献１参照）、電位の増加に応じてアルミニウムへの電子抵抗の大きい不動態皮膜の厚さが増加することになる。その結果、電子パスを形成している基板－導電助剤との接触域より不動態化が進み、電子パスが狭くなるため、オーミック過電圧が増加し、高出力化の妨げになる可能性が大きくなると懸念されている。 On the other hand, when the electrolyte salt is a salt that easily forms a fluorine compound or a compound compound of fluorine and oxygen represented by AlO x / 2 F 3-x , such as LiBF 4 or LiPF 6 (see Non-Patent Document 1). As the potential increases, the thickness of the passive film having a large electronic resistance to aluminum increases. As a result, the passivation proceeds more than the contact area between the substrate forming the electron path and the conductive additive, and the electron path is narrowed, so that the ohmic overvoltage increases and there is a great possibility that the high output is hindered. There are concerns.
　第３発明は、上記従来の実情に鑑みてなされたものであり、厳しい腐食環境下においても導電性を有し、かつ、優れた耐食性を示す集電体及び高電位で充電が行われる正極活物質を用いた電池であっても優れた耐食性を示す電池を提供することを解決すべき課題としている。 The third invention has been made in view of the above-described conventional situation, and has a current collector that has conductivity even in a severe corrosive environment and exhibits excellent corrosion resistance, and a positive electrode active material that is charged at a high potential. It is an issue to be solved to provide a battery that exhibits excellent corrosion resistance even with a battery using a substance.
　第１の電池は、アルミニウム、ニッケル若しくはチタンを主要構成成分とする集電体基材又はオーステナイト系ステンレスからなる集電体基材の表面に、導電性ダイヤモンドライクカーボン、グラッシーカーボン、金及び白金のうちの一種又は二種以上からなる導電性の耐食性皮膜が形成された集電体と、
　有機溶媒と、を備えた電池であって、
　前記有機溶媒には、鎖式飽和炭化水素化合物の両末端にニトリル基が結合した鎖式飽和炭化水素ジニトリル化合物、鎖式エーテル化合物の末端の少なくとも一つにニトリル基が結合した鎖式エーテルニトリル化合物及びシアノ酢酸エステルのうち少なくとも一つのニトリル化合物と、環状カーボネート、環状エステル及び鎖状カーボネートのうち少なくとも一つと、が含まれていることを特徴とする。 The first battery is made of conductive diamond-like carbon, glassy carbon, gold and platinum on the surface of a current collector base material mainly composed of aluminum, nickel or titanium or a current collector base material made of austenitic stainless steel. A current collector on which a conductive corrosion-resistant film made of one or more of them is formed;
A battery comprising an organic solvent,
The organic solvent includes a chain saturated hydrocarbon dinitrile compound in which a nitrile group is bonded to both ends of a chain saturated hydrocarbon compound, and a chain ether nitrile compound in which a nitrile group is bonded to at least one terminal of a chain ether compound. And at least one nitrile compound of cyanoacetate and at least one of cyclic carbonate, cyclic ester and chain carbonate.
　第１の電池では、アルミニウム、ニッケル若しくはチタンを主要構成成分とする集電体基材又はオーステナイト系ステンレスからなる集電体基材の表面に、導電性ダイヤモンドライクカーボン、グラッシーカーボン、金及び白金のうちの一種又は二種以上からなる導電性の耐食性皮膜が形成された集電体を用いているため、集電体が優れた耐食性を示す。
　また、電解液は、鎖式飽和炭化水素化合物の両末端にニトリル基が結合した鎖式飽和炭化水素ジニトリル化合物、鎖式エーテル化合物の末端の少なくとも一つにニトリル基が結合した鎖式エーテルニトリル化合物及びシアノ酢酸エステルのうち少なくとも一つのニトリル化合物と、環状カーボネート、環状エステル及び鎖状カーボネートのうち少なくとも一つと、が含まれている有機溶媒を含んでいる。このため、電極上や集電体上にニトリルを起源とする優れた耐食性皮膜が形成され、電解液に対して、さらに優れた耐食性を有する電池となる。 In the first battery, conductive diamond-like carbon, glassy carbon, gold, and platinum are formed on the surface of a current collector base material mainly composed of aluminum, nickel, or titanium or a current collector base material made of austenitic stainless steel. Since the current collector on which a conductive corrosion-resistant film made of one or more of them is formed is used, the current collector exhibits excellent corrosion resistance.
The electrolytic solution is a chain saturated hydrocarbon dinitrile compound in which a nitrile group is bonded to both ends of a chain saturated hydrocarbon compound, or a chain ether nitrile compound in which a nitrile group is bonded to at least one terminal of a chain ether compound. And an organic solvent containing at least one nitrile compound of cyanoacetate and at least one of cyclic carbonate, cyclic ester and chain carbonate. For this reason, the excellent corrosion-resistant film | membrane originating in a nitrile is formed on an electrode or an electrical power collector, and it becomes a battery which has the further outstanding corrosion resistance with respect to electrolyte solution.
　本発明の集電体は、アルミニウム、ニッケル若しくはチタンを主要構成成分とする集電体基材又はオーステナイト系ステンレスからなる集電体基材の表面に、導電性ダイヤモンドライクカーボン、グラッシーカーボン、金及び白金のうちの一種又は二種以上からなる導電性の耐食性皮膜が形成された集電体であって、
　前記該耐食性皮膜は欠陥が存在しており、該欠陥から露出する前記集電体基材の表面は、該集電体基材のフッ素化合物、酸素化合物、窒素化合物、炭素化合物、リン化合物、ホウ素化合物のうちの一種又は二種以上からなる不動態皮膜で覆われていることを特徴とする。 The current collector of the present invention has conductive diamond-like carbon, glassy carbon, gold and the like on the surface of a current collector base material comprising aluminum, nickel or titanium as a main constituent or a current collector base material made of austenitic stainless steel. A current collector on which a conductive corrosion-resistant film made of one or more of platinum is formed,
The corrosion-resistant film has defects, and the surface of the current collector substrate exposed from the defects is a fluorine compound, oxygen compound, nitrogen compound, carbon compound, phosphorus compound, boron of the current collector substrate. It is characterized by being covered with a passive film composed of one or more of the compounds.
　本発明の集電体では、アルミニウム、ニッケル若しくはチタンを主要構成成分とする集電体基材又はオーステナイト系ステンレスからなる集電体基材が用いられている。ここで「アルミニウム、ニッケル若しくはチタンを主要構成成分とする」とはアルミニウム、ニッケル又はチタンが９０質量％以上含まれている金属をいう。そして、集電体基材の表面には導電性ダイヤモンドライクカーボン、グラッシーカーボン、金及び白金のうちの一種又は二種以上からなる導電性の耐食性皮膜が形成されているため、電解質塩がＬｉＴＦＳＩやＬｉＢＥＴＩなど、容易に耐食性を有するフッ素化合物もしくフッ素と酸素の複合化合物を形成しない塩の場合であっても、アルミニウムやニッケルやチタンやオーステナイト系ステンレスが剥き出しとなった集電体よりも、はるかに高い電子伝導性を有し、かつ、耐食性に優れた広い電位窓を有する集電体となる。 In the current collector of the present invention, a current collector base material mainly composed of aluminum, nickel or titanium or a current collector base material made of austenitic stainless steel is used. Here, “having aluminum, nickel, or titanium as a main constituent” refers to a metal containing 90% by mass or more of aluminum, nickel, or titanium. And since the electroconductive corrosion-resistant film which consists of 1 type or 2 types or more of electroconductive diamond-like carbon, glassy carbon, gold | metal | money, and platinum is formed in the surface of a collector base material, electrolyte salt is LiTFSI, Even in the case of a salt such as LiBETI that does not readily form a fluorine compound or a compound compound of fluorine and oxygen that has corrosion resistance, it is far more than the collector in which aluminum, nickel, titanium, or austenitic stainless steel is exposed. Therefore, the current collector has a wide potential window with high electron conductivity and excellent corrosion resistance.
　また、耐食性皮膜に存在するに欠陥にから露出する集電体基材の表面が、該集電体基材のフッ素化合物、酸素化合物、窒素化合物、炭素化合物、リン化合物、ホウ素化合物のうちの一種又は二種以上からなる不動態皮膜で覆われているので、耐食性皮膜に存在する欠陥からの腐食の進行が、この不動態皮膜によって防止される。このため、導電性の耐食性皮膜に欠陥がない場合と同様に、単にアルミニウムやニッケルやチタンやオーステナイト系ステンレスからなる集電体よりも、はるかに高い導電性を有し、かつ、耐食性が優れた集電体となる。 In addition, the surface of the current collector base that is exposed to defects in the corrosion-resistant film is one of the fluorine compound, oxygen compound, nitrogen compound, carbon compound, phosphorus compound, and boron compound of the current collector base. Or since it is covered with the passive film which consists of 2 or more types, the progress of corrosion from the defect which exists in a corrosion-resistant film | membrane is prevented by this passive film. For this reason, it has much higher conductivity and excellent corrosion resistance than a current collector made of aluminum, nickel, titanium, or austenitic stainless steel, as in the case where there is no defect in the conductive corrosion-resistant film. It becomes a current collector.
　オーステナイト系ステンレスとしては、日本工業規格で規定するＳＵＳ３０４、ＳＵＳ３１６及びＳＵＳ３０６Ｌのうちの一種又は二種以上を用いることができる。 As the austenitic stainless steel, one or more of SUS304, SUS316, and SUS306L defined by Japanese Industrial Standard can be used.
　一方、電解質塩がＬｉＢＦ４やＬｉＰＦ６など、容易にフッ化物を形成するような塩の場合は、電位の増加に応じて、アルミニウム等に形成される電子抵抗の大きいフッ素化合物もしくフッ素と酸素の複合化合物からなる不動態皮膜の厚さが、増加することで、１０V以上の高電位でも耐蝕性が確保できる。その背反としてフッ素化合物もしくフッ素と酸素の複合化合物からなる不動態皮膜部分の電子伝導性は低下するが、本発明の集電体では、集電体基材のほとんどの部分が導電性を有するダイヤモンドライクカーボン、グラッシーカーボン、金及び白金のうちの一種又は二種以上で覆われているため、集電体基材の不動態皮膜による電子伝導性の低下は、欠陥部分の極わずかな面積でのみ発生するだけである。従って、高電圧化しても電子伝導性の低下は無視できる程度となり、懸念されている高電圧化による出力低下は防ぐことが可能となる。 On the other hand, in the case where the electrolyte salt is a salt that easily forms a fluoride, such as LiBF 4 or LiPF 6 , a fluorine compound with high electronic resistance or fluorine and oxygen formed on aluminum or the like as the potential increases. By increasing the thickness of the passive film made of the composite compound, corrosion resistance can be secured even at a high potential of 10 V or higher. On the contrary, the electronic conductivity of the passive film portion made of a fluorine compound or a composite compound of fluorine and oxygen is lowered, but in the current collector of the present invention, most of the current collector base material has conductivity. Since it is covered with one or more of diamond-like carbon, glassy carbon, gold, and platinum, the decrease in electron conductivity due to the passive film on the current collector substrate is caused by a very small area of the defective portion. Only occurs. Therefore, even if the voltage is increased, the decrease in electron conductivity is negligible, and it is possible to prevent the decrease in output caused by the increased voltage.
　本発明において導電性ダイヤモンドライクカーボンとは、ダイヤモンド結合（炭素同士のＳＰ３混成軌道結合）とグラファイト結合（炭素同士のＳＰ２混成軌道結合）の両方の結合が混在しているアモルファス構造をとるカーボンのうち、導電性が１０００Ωcm以下のものをいう。ただし、アモルファス構造以外に、部分的にグラファイト構造からなる結晶構造（すなわちＳＰ２混成軌道結合からなる六方晶系結晶構造）からなる相を有し、これにより導電性が発揮されるものも含まれる。グラファイトとダイヤモンドの中間の性質を有するダイヤモンドライクカーボンは、成膜時にダイヤモンドライクカーボンを構成する炭素原子のＳＰ２混成軌道結合とＳＰ３混成軌道結合の比率を調整することで、導電性を調節することができる。また、カーボン以外の異種元素を微量元素置換することで、導電性と耐食性を調整することができる。異種元素の種類としては、Ｔｉ，Ｃｒ，Ａｌ，Ｆｅ，Ｎｉ，Ｃｕ，Ａｇ，Ｍｏ，Ｗ，Ｂ、Ｓｉ等が挙げられる。 In the present invention, the conductive diamond-like carbon is a carbon having an amorphous structure in which both diamond bonds (SP 3 hybrid orbital bonds between carbons) and graphite bonds (SP 2 hybrid orbital bonds between carbons) are mixed. Among them, the one whose conductivity is 1000 Ωcm or less. However, in addition to the amorphous structure, those having a phase composed of a crystal structure partially composed of a graphite structure (that is, a hexagonal crystal structure composed of SP 2 hybrid orbital bonds) and thereby exhibiting conductivity are also included. . Diamond-like carbon having properties intermediate between graphite and diamond adjusts the conductivity by adjusting the ratio of SP 2 hybrid orbital bonds and SP 3 hybrid orbital bonds of the carbon atoms constituting diamond-like carbon during film formation. be able to. In addition, the conductivity and corrosion resistance can be adjusted by substituting trace elements for different elements other than carbon. Examples of the different elements include Ti, Cr, Al, Fe, Ni, Cu, Ag, Mo, W, B, and Si.
　上記のごとく、本発明の集電体は極めて耐食性に優れ、広い電位窓を有するため、充電電圧の高いリチウムイオン電池やナトリウムイオン電池等、電気二重層キャパシター、リチウムイオンキャパシター各種蓄電体の集電体として好適に用いることができる。 As described above, since the current collector of the present invention is extremely excellent in corrosion resistance and has a wide potential window, the current collectors of various electric storage devices such as lithium ion batteries and sodium ion batteries with high charging voltage, such as electric double layer capacitors and lithium ion capacitors. It can be suitably used as a body.
　本発明の第２の電池は、アルミニウム、ニッケル若しくはチタンを主要構成成分とする集電体基材又はオーステナイト系ステンレスからなる集電体基材の表面に、導電性ダイヤモンドライクカーボン、グラッシーカーボン、金及び白金のうちの一種又は二種以上からなる導電性の耐食性皮膜が形成された集電体と、ＢＦ４アニオンとＰＦ６アニオンとの少なくとも一方を有する電解質を含む電解液と、を備えたことを特徴とする。 The second battery of the present invention has conductive diamond-like carbon, glassy carbon, gold on the surface of a current collector base material composed mainly of aluminum, nickel or titanium or a current collector base material made of austenitic stainless steel. And a current collector on which a conductive corrosion-resistant film made of one or more of platinum is formed, and an electrolytic solution containing an electrolyte having at least one of BF 4 anion and PF 6 anion. It is characterized by.
　本発明の第２発明の電池では、アルミニウム、ニッケル若しくはチタンを主要構成成分とする集電体基材又はオーステナイト系ステンレスからなる集電体基材の表面に、導電性ダイヤモンドライクカーボン、グラッシーカーボン、金及び白金のうちの一種又は二種以上からなる導電性の耐食性皮膜が形成された集電体を用いているため、集電体が優れた耐食性を示す。
　さらには、電解質にＢＦ４アニオンとＰＦ６アニオンとの少なくとも一方を有するため、フッ素等を含む優れた耐食性皮膜が形成される。 In the battery of the second invention of the present invention, conductive diamond-like carbon, glassy carbon, on the surface of a current collector base material comprising aluminum, nickel or titanium as a main component or a current collector base material made of austenitic stainless steel, Since the current collector on which a conductive corrosion-resistant film made of one or more of gold and platinum is formed is used, the current collector exhibits excellent corrosion resistance.
Furthermore, since the electrolyte has at least one of BF 4 anion and PF 6 anion, an excellent corrosion-resistant film containing fluorine or the like is formed.
　本発明の第２の電池において、前記電解液は、鎖式飽和炭化水素化合物の両末端にニトリル基が結合した鎖式飽和炭化水素ジニトリル化合物、鎖式エーテル化合物の末端の少なくとも一つにニトリル基が結合した鎖式エーテルニトリル化合物及びシアノ酢酸エステルのうち少なくとも一つのニトリル化合物と、環状カーボネート、環状エステル及び鎖状カーボネートのうち少なくとも一つと、が含まれている有機溶媒を含んでもよい。こうであれば、電極上や集電体上にニトリルを起源とする優れた耐食性皮膜が形成され、電解液に対して、さらに優れた耐食性を有する電池となる。 In the second battery of the present invention, the electrolyte includes a chain saturated hydrocarbon dinitrile compound in which a nitrile group is bonded to both ends of the chain saturated hydrocarbon compound, and a nitrile group at least at one end of the chain ether compound. An organic solvent containing at least one nitrile compound among a chain ether nitrile compound and a cyanoacetate bonded to each other and at least one of a cyclic carbonate, a cyclic ester, and a chain carbonate may be included. If it is like this, the outstanding corrosion-resistant film | membrane originating in a nitrile will be formed on an electrode or an electrical power collector, and it will become a battery which has the further outstanding corrosion resistance with respect to electrolyte solution.
第１発明の実施形態の二次電池の断面模式図である。It is a cross-sectional schematic diagram of the secondary battery of embodiment of 1st invention. 第１発明の実施形態の二次電池用正極の拡大模式図である。It is an expansion schematic diagram of the positive electrode for secondary batteries of embodiment of 1st invention. １Ｍ　ＬｉＰＦ６／ＥＣ-ＤＭＣ-セバコニトリル（容量比２５：２５：５０）の電解液中における実験例１～３及び比較例１～３の二次電池正極用導電助剤の電位－電流曲線である。FIG. 5 is a potential-current curve of conductive assistants for secondary battery positive electrodes of Experimental Examples 1 to 3 and Comparative Examples 1 to 3 in an electrolyte solution of 1M LiPF 6 / EC-DMC-sebacononitrile (capacity ratio 25:25:50). . １Ｍ　ＬｉＢＦ４／ＥＣ-ＤＭＣ-セバコニトリル（容量比２５：２５：５０）の電解液中における実験例１、３及び４並びに比較例１～３の二次電池正極用導電助剤の電位－電流曲線である。Potential-current curves of conductive assistants for secondary battery positive electrodes of Experimental Examples 1, 3, and 4 and Comparative Examples 1 to 3 in an electrolyte solution of 1M LiBF 4 / EC-DMC-sebacononitrile (capacity ratio 25:25:50) It is. １Ｍ　ＬｉＴＦＳＩ／ＥＣ-ＤＭＣ-セバコニトリル（容量比２５：２５：５０）の電解液中における実験例１、３及び４並びに比較例１～３比較例１～３の二次電池用正極用導電助剤の電位－電流曲線である。Conductive aid for positive electrodes for secondary batteries of Experimental Examples 1, 3 and 4 and Comparative Examples 1 to 3 and Comparative Examples 1 to 3 in an electrolyte solution of 1M LiTFSI / EC-DMC-Sebacononitrile (capacity ratio 25:25:50) Is a potential-current curve. 第２発明の実施形態の二次電池の断面模式図である。It is a cross-sectional schematic diagram of the secondary battery of embodiment of 2nd invention. 第２発明の実施形態の二次電池用正極の拡大模式図である。It is an expansion schematic diagram of the positive electrode for secondary batteries of embodiment of 2nd invention. 実験例１及び比較例１～３の二次電池用正極の電位－電流曲線である。6 is a potential-current curve of positive electrodes for secondary batteries of Experimental Example 1 and Comparative Examples 1 to 3. 実施形態の集電体の作製方法を示す模式図である。It is a schematic diagram which shows the preparation methods of the electrical power collector of embodiment. 実施例１及び比較例１～４の電極における電位と電流の関係を示すグラフである。6 is a graph showing the relationship between potential and current in the electrodes of Example 1 and Comparative Examples 1 to 4. 実施例３及び比較例１，５、８の電極の電位走査後のＸＰＳによる表面分析の結果を示すグラフである。It is a graph which shows the result of the surface analysis by XPS after the potential scan of the electrode of Example 3 and Comparative Examples 1, 5, and 8. 実施例２及び比較例５～７の電極における電位と電流の関係を示すグラフである。6 is a graph showing the relationship between potential and current in the electrodes of Example 2 and Comparative Examples 5 to 7. 実施例３及び比較例８の電極における電位と電流の関係を示すグラフである。It is a graph which shows the relationship between the electric potential in the electrode of Example 3 and Comparative Example 8, and an electric current. 実施例４及び比較例９の電極における電位と電流の関係を示すグラフである。It is a graph which shows the electric potential in the electrode of Example 4 and Comparative Example 9, and the relationship of an electric current. 実施例５及び比較例１０の電極における電位と電流の関係を示すグラフである。It is a graph which shows the relationship between the electric potential in the electrode of Example 5 and Comparative Example 10, and an electric current. 実施例６及び比較例１１の電極における電位と電流の関係を示すグラフである。It is a graph which shows the relationship between the electric potential in the electrode of Example 6 and Comparative Example 11, and an electric current. 実施例７の電極における電位と電流の関係を示すグラフである。10 is a graph showing the relationship between potential and current in an electrode of Example 7. 実施例８及び比較例１２～２０の電極における電位と電流の関係を示すグラフである。6 is a graph showing the relationship between potential and current in the electrodes of Example 8 and Comparative Examples 12 to 20. 実施例９及び比較例２１～２２の電極における電位と電流の関係を示すグラフである。10 is a graph showing the relationship between potential and current in electrodes of Example 9 and Comparative Examples 21 to 22. 実施例９の電極における電位と電流の関係を示すグラフである。10 is a graph showing the relationship between potential and current in an electrode of Example 9. 実施形態の集電体を用いたリチウムイオン電池の模式断面図である。It is a schematic cross section of a lithium ion battery using the current collector of the embodiment. 実施例１及び比較例１の電位－電流曲線である。2 is a potential-current curve of Example 1 and Comparative Example 1. FIG. 実施例２～９及び比較例１の電位－電流曲線である。2 is a potential-current curve of Examples 2 to 9 and Comparative Example 1. FIG. 比較例１の電位－電流曲線である。3 is a potential-current curve of Comparative Example 1. 実施例１０～１７及び比較例２の電位－電流曲線である。6 is a potential-current curve of Examples 10 to 17 and Comparative Example 2. FIG. 実施例１８～２５及び比較例３の電位－電流曲線である。6 is a potential-current curve of Examples 18 to 25 and Comparative Example 3. FIG. 実施例２６～３１及び比較例４の電位－電流曲線である。6 is a potential-current curve of Examples 26 to 31 and Comparative Example 4. FIG. 実施例３２、３３及び比較例５の電位－電流曲線である。6 is a potential-current curve of Examples 32 and 33 and Comparative Example 5. 実施例３４～３６及び比較例６の電位－電流曲線である。6 is a potential-current curve of Examples 34 to 36 and Comparative Example 6. FIG. 実施例３７～３９及び比較例７の電位－電流曲線である。10 is a potential-current curve of Examples 37 to 39 and Comparative Example 7. 実施例４１～４５及び比較例１の電位－電流曲線である。2 is a potential-current curve of Examples 41 to 45 and Comparative Example 1. FIG. 実施例４５及び比較例８の電位－電流曲線である。6 is a potential-current curve of Example 45 and Comparative Example 8. FIG. 実施例４６及び比較例８の電位－電流曲線である。10 is a potential-current curve of Example 46 and Comparative Example 8. 実施例４７及び比較例１の電位－電流曲線である。6 is a potential-current curve of Example 47 and Comparative Example 1. FIG. エチレンカーボネート：ジメチルカーボネート＝１：１とし、さらにセバコニトリルを所定量添加した混合溶媒における電位－電流曲線である。It is a potential-current curve in a mixed solvent in which ethylene carbonate: dimethyl carbonate = 1: 1 and a predetermined amount of sebacononitrile was added. 実施例４１のリチウムイオン電池用電解液を用いたリチウム吸蔵放出の電位－電流曲線である。42 is a potential-current curve of lithium storage / release using the electrolytic solution for a lithium ion battery of Example 41. FIG.
｛第１発明｝
　以下、第１発明を具体化した実施形態について説明する。
　まず、正極活物質の粉末を用意し、これに導電性助剤としてのグラシーカーボン粉末（及び／又はダイヤモンドライクカーボン粉体）と、結合剤としてのポリテトラエチレン（ＰＴＦＥ）やポリフッ化ビニリデン（ＰＶｄＦ）等のフッ素樹脂粉末とを加え、ホットプレスによって所望の形状に成形し、実施形態の二次電池用正極を得る。正極活物質としては、例えばＬｉ２ＮｉＰＯ４Ｆ、ＬｉＮｉＰＯ４、ＬｉＣｏＰＯ４、Ｌｉ２ＣｏＰＯ４Ｆ等のいずれか、あるいはこれらの混合物を用いることができる。これらの混合割合は、正極として必要とされる電子伝導性や、結合剤としての機能を奏するために必要なフッ素樹脂の添加量等を勘案して、適宜決定すればよい。代表的な割合としては、正極活物質粉末が６０～８０重量％、グラシーカーボン粉末が１５～３５重量％、フッ素樹脂粉末が３～１０重量％である。 {First invention}
Hereinafter, an embodiment embodying the first invention will be described.
First, a positive electrode active material powder is prepared, and a glassy carbon powder (and / or diamond-like carbon powder) as a conductive auxiliary agent and polytetraethylene (PTFE) or polyvinylidene fluoride (as a binder) PVdF) or other fluororesin powder is added and formed into a desired shape by hot pressing to obtain the positive electrode for secondary battery of the embodiment. As the positive electrode active material, for example, Li 2 NiPO 4 F, LiNiPO 4 , LiCoPO 4, Li 2 CoPO 4 either F or the like, or may be a mixture thereof. These mixing ratios may be appropriately determined in consideration of the electron conductivity required for the positive electrode, the addition amount of the fluororesin necessary for exhibiting the function as the binder, and the like. Typical ratios of the positive electrode active material powder are 60 to 80% by weight, the glassy carbon powder is 15 to 35% by weight, and the fluororesin powder is 3 to 10% by weight.
　このようにして成形したリチウムイオン電池用正極を用いて、図１に示すようなリチウムイオン電池８を製造することができる。すなわち、電解液が浸透可能なセパレータ１をリチウムイオン電池用正極２とグラファイトからなる負極３とで挟んで接合体４とし、電解液に浸漬する。そして、パッキン５を装填した負極用集電ケース６に負極３が接触するように接合体４を収容し、さらにリチウムイオン電池用正極２側から正極用集電板７を嵌挿した後、負極用集電ケース６と正極用集電板７とをかしめて密閉する。こうして、実施形態のリチウムイオン電池８を製造することができる。 The lithium ion battery 8 as shown in FIG. 1 can be manufactured using the positive electrode for a lithium ion battery thus formed. That is, the separator 1 through which the electrolytic solution can permeate is sandwiched between the positive electrode 2 for a lithium ion battery and the negative electrode 3 made of graphite to form a joined body 4 and immersed in the electrolytic solution. Then, the joined body 4 is accommodated so that the negative electrode 3 is in contact with the negative electrode current collecting case 6 loaded with the packing 5, and the positive electrode current collector plate 7 is inserted from the positive electrode 2 side for the lithium ion battery. The current collecting case 6 and the positive current collecting plate 7 are caulked and sealed. Thus, the lithium ion battery 8 of the embodiment can be manufactured.
　上記実施形態のリチウムイオン電池８のリチウムイオン電池用正極２では、図２に示すように、正極活物質粉末２ａ上にグラシーカーボン粉末２ｂとフッ素樹脂粉末２ｃが付着しており、フッ素樹脂粉末２ｃが結合剤として各粉末をつなぎとめて電極形状を保持している。そして、グラシーカーボン粉末２ｂが電子伝導性を担う導電補助剤としての役割を果たす。後述するように、グラシーカーボン粉末２ｂ（あるいはダイヤモンドライクカーボン粉末）は、リチウムイオン電池の電解液中において、単なるカーボンブラック粉末やグラファイト粉末よりも広い電位窓を有している。このため、正極活物質の充電過程における高い電位においても、安定に存在し、電解液溶媒の分解もほとんど発生しない。このため、導電助剤が充電時の高い電位において酸化されてしまったり、溶媒が分解したりしてしまうことがなく、ひいては、高い電位で充電反応が行われ、エネルギー密度の高い正極活物質を有効に活用することができる。 In the lithium ion battery positive electrode 2 of the lithium ion battery 8 of the above embodiment, as shown in FIG. 2, the glassy carbon powder 2b and the fluororesin powder 2c are attached on the positive electrode active material powder 2a. 2c holds each powder together as a binder to maintain the electrode shape. And the glassy carbon powder 2b plays a role as a conductive auxiliary agent responsible for electron conductivity. As will be described later, the glassy carbon powder 2b (or diamond-like carbon powder) has a wider potential window than the simple carbon black powder or graphite powder in the electrolyte of the lithium ion battery. For this reason, even at a high potential in the charging process of the positive electrode active material, it stably exists and hardly decomposes the electrolyte solvent. For this reason, the conductive auxiliary agent is not oxidized at a high potential during charging or the solvent is not decomposed. As a result, a charging reaction is performed at a high potential, and a positive electrode active material having a high energy density is obtained. It can be used effectively.
＜実験例＞
　以下、本発明の二次電池用正極の発明の効果について立証するため、様々な導電性物質粉体をＰＴＦＥ粉体と混合してホットプレス法によって円盤状電極を作製し、電位－電流曲線を測定した。 <Experimental example>
Hereinafter, in order to verify the effect of the invention of the positive electrode for secondary battery of the present invention, various conductive substance powders are mixed with PTFE powder to produce a disk-shaped electrode by hot pressing, and a potential-current curve is obtained. It was measured.
（実験例１）
　実験例１では、グラシーカーボン粉（平均粒径０．５μｍ）４ｍｇとＰＴＦＥ粉体１ｍｇとを混合し、ホットプレスによって８ｍｍφの円盤状の電極を作製した。 (Experimental example 1)
In Experimental Example 1, 4 mg of glassy carbon powder (average particle size 0.5 μm) and 1 mg of PTFE powder were mixed, and an 8 mmφ disc-shaped electrode was produced by hot pressing.
（実験例２）
　実験例２では、グラシーカーボン粉砕品（平均粒径８μｍ）４ｍｇとＰＴＦＥ粉体１ｍｇとを混合し、ホットプレスによって８ｍｍφの円盤状の電極を作製した。 (Experimental example 2)
In Experimental Example 2, 4 mg of a glassy carbon pulverized product (average particle diameter: 8 μm) and 1 mg of PTFE powder were mixed, and an 8 mmφ disk-shaped electrode was produced by hot pressing.
（実験例３）
　実験例３では、ダイヤモンドライクカーボン粉末（平均粒径０．０３μｍ）４ｍｇとＰＴＦＥ粉体１ｍｇとを混合し、ホットプレスによって８ｍｍφの円盤状の電極を作製した。
（実験例４）
　実験例４では、グラシーカーボン粉砕品（平均粒径０．５μｍ）にＰｔを２０重量％担持したＰｔ担持グラッシーカーボン粉砕品４ｍｇとＰＴＦＥ粉体１ｍｇとを混合し、ホットプレスによって８ｍｍφの円盤状の電極を作製した。 (Experimental example 3)
In Experimental Example 3, 4 mg of diamond-like carbon powder (average particle size 0.03 μm) and 1 mg of PTFE powder were mixed, and an 8 mmφ disk-shaped electrode was produced by hot pressing.
(Experimental example 4)
In Experimental Example 4, 4 mg of a Pt-supported glassy carbon product on which 20% by weight of Pt was supported on a glassy carbon product (average particle size of 0.5 μm) and 1 mg of PTFE powder were mixed, and a disk shape of 8 mmφ was formed by hot pressing. An electrode was prepared.
（比較例１）
　比較例１は、市販のグラシーカーボン板そのものである (Comparative Example 1)
Comparative Example 1 is a commercially available glassy carbon plate itself.
（比較例２）
　比較例２では、カーボンブラック（電気化学工業社製「ＨＳ－１００」）１５ｍｇとＰＴＦＥ粉体１５ｍｇとを混合し、ホットプレスによって８ｍｍφの円盤状の電極を作製した。 (Comparative Example 2)
In Comparative Example 2, 15 mg of carbon black (“HS-100” manufactured by Denki Kagaku Kogyo Co., Ltd.) and 15 mg of PTFE powder were mixed, and an 8 mmφ disk-shaped electrode was produced by hot pressing.
（比較例３）
　実験例３では、カーボンブラック（電気化学工業社製「ＨＳ－１００」）を真空中３０００℃で３時間熱処理を行なったものを４ｍｇとＰＴＦＥ粉体１ｍｇとを混合し、ホットプレスによって８ｍｍφの円盤状の電極を作製した。 (Comparative Example 3)
In Experimental Example 3, carbon black (“HS-100” manufactured by Denki Kagaku Kogyo Co., Ltd.), which was heat-treated at 3000 ° C. for 3 hours in a vacuum, 4 mg and 1 mg of PTFE powder were mixed, and an 8 mmφ disc was hot-pressed. A shaped electrode was prepared.
＜電位－電流曲線の測定＞
　上記のようにして作製した実験例１～３及び比較例１～３の電極について、リチウムイオン電池用電解液中で電位走査し、電位－電流曲線を測定した。電解液は次のように調製した。すなわち、エチレンカーボネートとジメチルカーボネートとセバコニトリルとを容量比で２５：２５：５０となるように混合液を調製し、さらにＬｉＰＦ６を１ｍｏｌ／Ｌとなるように溶解した溶液を電解液とし、三極式電解セル容器に入れた。 <Measurement of potential-current curve>
The electrodes of Experimental Examples 1 to 3 and Comparative Examples 1 to 3 produced as described above were subjected to potential scanning in an electrolytic solution for a lithium ion battery, and a potential-current curve was measured. The electrolytic solution was prepared as follows. That is, a mixed solution was prepared such that ethylene carbonate, dimethyl carbonate, and sebaconitrile were in a volume ratio of 25:25:50, and a solution in which LiPF 6 was dissolved so as to be 1 mol / L was used as an electrolytic solution. Placed in an electrolytic cell container.
　電位－電流曲線の測定は、作用極として上記電極（面積０．５ｃｍ２）、対極として白金網、参照電極としてLi金属を用いた。掃引速度は５ｍＶ／ｓｅｃとした。 In the measurement of the potential-current curve, the above electrode (area 0.5 cm 2 ) was used as a working electrode, a platinum net as a counter electrode, and Li metal as a reference electrode. The sweep speed was 5 mV / sec.
　その結果、図３に示すように、グラシーカーボン粉末を用いた実験例１、２及びダイヤモンドライクカーボンを用いた実験例３の電極では、比較例１のグラシーカーボン板電極とよりも広い電位窓を有していることが分かった。これに対して、カーボンブラックをそのまま電極とした比較例２では、電位窓が狭く、カーボンブラックを熱処理してグラファイト化した比較例３においても、電位窓が多少広がったものの、４．８Ｖ程度で５０μＡ／ｃｍ２となり、実験例１～３と比較して、電位窓が狭いことが分かった。
　また、電解質を１Ｍ　ＬｉＢＦ４へ変更して同様な測定をおこなった。その結果を図４に示す。この場合も比較例２のカーボンブラックやカーボンブラックを熱処理してグラファイト化した比較例３よりも、グラッシーカーボン粉砕品の実験例１やダイヤモンドライクカーボン粉末の実験例３や、Ｐｔ担持グラッシーカーボンの実験例４の方が、高電位側で電位窓が広がることがわかった。
　さらに、電解質を１Ｍ　ＬｉＴＦＳＩへ変更して同様な試験をおこなった。その結果を図５に示す。この場合も比較例２の比較例２のカーボンブラックやカーボンブラックを熱処理してグラファイト化した比較例３よりも、グラッシーカーボン粉砕品の実験例１の方が、高電位側で電位窓が広がることがわかった。 As a result, as shown in FIG. 3, the electrodes of Experimental Examples 1 and 2 using glassy carbon powder and Experimental Example 3 using diamond-like carbon have a wider potential than the glassy carbon plate electrode of Comparative Example 1. It turns out that it has a window. In contrast, in Comparative Example 2 in which carbon black was used as an electrode as it was, the potential window was narrow, and in Comparative Example 3 in which carbon black was heat-treated and graphitized, the potential window was slightly widened, but at about 4.8V. It was 50 μA / cm 2 , indicating that the potential window was narrow compared to Experimental Examples 1 to 3.
Moreover, the electrolyte was changed to 1M LiBF4 and the same measurement was performed. The result is shown in FIG. Also in this case, the experimental example 1 of the crushed glassy carbon, the experimental example 3 of the diamond-like carbon powder, and the experiment of the Pt-supported glassy carbon, rather than the comparative example 3 in which carbon black or carbon black in the comparative example 2 is heat treated and graphitized. In Example 4, it was found that the potential window widened on the high potential side.
Further, the same test was performed by changing the electrolyte to 1M LiTFSI. The result is shown in FIG. Also in this case, the potential window is widened on the high potential side in the experimental example 1 of the crushed glassy carbon product than in the comparative example 3 in which the carbon black in the comparative example 2 in the comparative example 2 or the carbon black is graphitized by heat treatment. I understood.
　以上の結果から、導電助剤としてグラシーカーボン粉末、ダイヤモンドライクカーボン粉末をリチウム電池の正極活物質粉末やＰｔ担持グラッシーカーボン粉末に添加した実施形態のリチウムイオン電池では、リチウムイオン電池用の充電時に高い電位とされる正極においても、分解されることなく、溶媒を分解するおそれも少ないことが分かった。そして、この結果から、高い電位で充電反応が行われるエネルギー密度の高い正極活物質を有効に活用できることが分かった。 From the above results, in the lithium ion battery of the embodiment in which the glassy carbon powder and the diamond-like carbon powder are added as the conductive auxiliary agent to the positive electrode active material powder of the lithium battery and the Pt-supported glassy carbon powder, when charging for the lithium ion battery, It was found that the positive electrode having a high potential was not decomposed and there was little possibility of decomposing the solvent. From this result, it was found that a positive electrode active material having a high energy density in which a charging reaction is performed at a high potential can be effectively used.
｛第２発明｝
　以下、第２発明を具体化した実施形態について説明する。
　まず、正極活物質の粉末を用意し、乾式めっき法によって、正極活物質の粉末の表面にダイヤモンドライクカーボンを付着させる。
　ダイヤモンドライクカーボンを正極活物質の粉末に付着させるための乾式めっき法としては、特に限定はされないが、例えばイオン化蒸着法を用いることができる。すなわち、真空チャンバー中にベンゼンや炭化水素ガスを導入し、直流アーク放電プラズマ中でイオンを生成させ、直流の負電圧にバイアスされた正極活物質の粉末にバイアス電圧に応じたエネルギーで衝突させて正極活物質の粉末の表面にダイヤモンドライクカーボンを付着させる方法である。 {Second invention}
Hereinafter, an embodiment embodying the second invention will be described.
First, a positive electrode active material powder is prepared, and diamond-like carbon is adhered to the surface of the positive electrode active material powder by dry plating.
Although it does not specifically limit as a dry-type plating method for making diamond-like carbon adhere to the powder of a positive electrode active material, For example, an ionization vapor deposition method can be used. In other words, benzene or hydrocarbon gas is introduced into a vacuum chamber, ions are generated in a DC arc discharge plasma, and collided with a positive active material powder biased to a DC negative voltage with energy corresponding to the bias voltage. In this method, diamond-like carbon is attached to the surface of the positive electrode active material powder.
　ダイヤモンドライクカーボンを正極活物質の粉末に付着させるためのその他の方法としては、高周波プラズマ法が挙げられる。この方法は、メタンガスを原料に使い、容量結合型のプラズマ電極を用いる方法である。 As another method for attaching diamond-like carbon to the powder of the positive electrode active material, a high-frequency plasma method can be mentioned. In this method, methane gas is used as a raw material, and a capacitively coupled plasma electrode is used.
　さらには、炭化水素ガスの熱分解によってダイヤモンドライクカーボンを正極活物質の粉末に付着させることもできる（例えば特開２００８－２６０６７０号公報）。 Furthermore, diamond-like carbon can be attached to the powder of the positive electrode active material by thermal decomposition of hydrocarbon gas (for example, JP 2008-260670 A).
　また、スパッタリングの手法で正極活物質の粉末の表面にダイヤモンドライクカーボンを付着させることもできる（例えば特開２００４－３３９５６４号公報）。
すなわち、真空中において、電子を電界によって加速してアルゴンガスに衝突させてアルゴンをイオン化し、これを電界によって加速して固体カーボンターゲット衝突させてスパッタリングさせ、正極活物質の粉末上にダイヤモンドライクカーボンを形成させる方法である（このとき、正極活物質に印加する負のバイアス電圧をかけてもよい。）。 Further, diamond-like carbon can be attached to the surface of the positive electrode active material powder by a sputtering method (for example, JP-A-2004-339564).
That is, in a vacuum, electrons are accelerated by an electric field and collided with argon gas to ionize argon, which is accelerated by the electric field and collided with a solid carbon target to be sputtered, and diamond-like carbon is formed on the positive electrode active material powder. (At this time, a negative bias voltage applied to the positive electrode active material may be applied).
　上記のような、様々な乾式めっき法によって、表面にダイヤモンドライクカーボンを付着させた正極活物質の粉末を用意し、これに結合剤としてのポリテトラエチレン（ＰＴＦＥ）やポリフッ化ビニリデン（ＰＶｄＦ）等のフッ素樹脂粉末とを加え、ホットプレスによって所望の形状に成形し、実施形態の二次電池用正極を得る。正極活物質としては、例えばＬｉ２ＮｉＰＯ４Ｆ、ＬｉＮｉＰＯ４、ＬｉＣｏＰＯ４、Ｌｉ２ＣｏＰＯ４Ｆ等のいずれか、あるいはこれらの混合物を用いることができる。これらの混合割合は、正極として必要とされる電子伝導性や、結合剤としての機能を奏するために必要なフッ素樹脂の添加量等を勘案して、適宜決定すればよい。 A positive electrode active material powder having diamond-like carbon attached to the surface is prepared by various dry plating methods as described above, and polytetraethylene (PTFE), polyvinylidene fluoride (PVdF), or the like as a binder is prepared. Are added into a desired shape by hot pressing to obtain the positive electrode for secondary battery of the embodiment. As the positive electrode active material, for example, Li 2 NiPO 4 F, LiNiPO 4 , LiCoPO 4, Li 2 CoPO 4 either F or the like, or may be a mixture thereof. These mixing ratios may be appropriately determined in consideration of the electron conductivity required for the positive electrode, the addition amount of the fluororesin necessary for exhibiting the function as the binder, and the like.
　このようにして成形したリチウムイオン電池用正極を用いて、図６に示すようなリチウムイオン電池１８を製造することができる。すなわち、電解液が浸透可能なセパレータ１１をリチウムイオン電池用正極２とグラファイトからなる負極１３とで挟んで接合体１４とし、電解液に浸漬する。そして、パッキン１５を装填した負極用集電ケース１６に負極１３が接触するように接合体１４を収容し、さらにリチウムイオン電池用正極１２側から正極用集電板１７を嵌挿した後、負極用集電ケース１６と正極用集電板１７とをかしめて密閉する。こうして、実施形態のリチウムイオン電池１８を製造することができる。 A lithium ion battery 18 as shown in FIG. 6 can be manufactured using the positive electrode for a lithium ion battery thus formed. That is, the separator 11 into which the electrolytic solution can permeate is sandwiched between the lithium ion battery positive electrode 2 and the negative electrode 13 made of graphite to form a joined body 14 and immersed in the electrolytic solution. Then, the joined body 14 is accommodated so that the negative electrode 13 is in contact with the negative electrode current collecting case 16 loaded with the packing 15, and the positive electrode current collector plate 17 is inserted from the positive electrode 12 side for the lithium ion battery. The current collecting case 16 and the positive current collecting plate 17 are caulked and sealed. Thus, the lithium ion battery 18 of the embodiment can be manufactured.
　上記実施形態のリチウムイオン電池１８のリチウムイオン電池用正極１２では、図７に示すように、正極活物質粉末１２ａ上にダイヤモンドライクカーボン１２ｂとフッ素樹脂粉末１２ｃが付着しており、フッ素樹脂粉末１２ｃが結合剤として各粉末をつなぎとめて電極形状を保持している。そして、ダイヤモンドライクカーボン１２ｂが電子伝導性を担う導電補助剤としての役割を果たす。後述するように、ダイヤモンドライクカーボン１２ｂは、リチウムイオン電池の電解液中において、単なるカーボンブラック粉末やグラファイト粉末よりも広い電位窓を有している。このため、正極活物質の充電過程における高い電位においても、安定に存在し、電解液溶媒の分解もほとんど発生しない。このため、導電助剤が充電時の高い電位において酸化されてしまったり、溶媒が分解したりしてしまうことがなく、ひいては、高い電位で充電反応が行われ、エネルギー密度の高い正極活物質を有効に活用することができる。 In the lithium ion battery positive electrode 12 of the lithium ion battery 18 of the above embodiment, as shown in FIG. 7, the diamond-like carbon 12b and the fluororesin powder 12c are attached on the positive electrode active material powder 12a, and the fluororesin powder 12c. However, the powder is held as a binder to maintain the electrode shape. The diamond-like carbon 12b plays a role as a conductive auxiliary agent responsible for electronic conductivity. As will be described later, the diamond-like carbon 12b has a wider potential window in the electrolyte of a lithium ion battery than a simple carbon black powder or graphite powder. For this reason, even at a high potential in the charging process of the positive electrode active material, it stably exists and hardly decomposes the electrolyte solvent. For this reason, the conductive auxiliary agent is not oxidized at a high potential during charging or the solvent is not decomposed. As a result, a charging reaction is performed at a high potential, and a positive electrode active material having a high energy density is obtained. It can be used effectively.
＜実験例＞
　以下、本発明の二次電池用正極の発明の効果について立証するため、様々な導電性物質粉体をＰＴＦＥ粉体と混合してホットプレス法によって円盤状電極を作製し、電位－電流曲線を測定した。 <Experimental example>
Hereinafter, in order to verify the effect of the invention of the positive electrode for secondary battery of the present invention, various conductive substance powders are mixed with PTFE powder to produce a disk-shaped electrode by hot pressing, and a potential-current curve is obtained. It was measured.
（実験例１）
　実験例１では、ダイヤモンドライクカーボン粉末（平均粒径０．０３μｍ）４ｍｇとＰＴＦＥ粉体１ｍｇとを混合し、ホットプレスによって８ｍｍφの円盤状の電極を作製した。 (Experimental example 1)
In Experimental Example 1, 4 mg of diamond-like carbon powder (average particle size 0.03 μm) and 1 mg of PTFE powder were mixed, and an 8 mmφ disk-shaped electrode was produced by hot pressing.
（比較例１）
　比較例１は、市販のグラシーカーボン板そのものである (Comparative Example 1)
Comparative Example 1 is a commercially available glassy carbon plate itself.
（比較例２）
　比較例２では、カーボンブラック（電気化学工業社製「ＨＳ－１００」）１５ｍｇとＰＴＦＥ粉体１５ｍｇとを混合し、ホットプレスによって８ｍｍφの円盤状の電極を作製した。 (Comparative Example 2)
In Comparative Example 2, 15 mg of carbon black (“HS-100” manufactured by Denki Kagaku Kogyo Co., Ltd.) and 15 mg of PTFE powder were mixed, and an 8 mmφ disk-shaped electrode was produced by hot pressing.
（比較例３）
　実験例３では、カーボンブラック（電気化学工業社製「ＨＳ－１００」）を真空中３０００℃で３時間熱処理を行なったものを１５ｍｇとＰＴＦＥ粉体１５ｍｇとを混合し、ホットプレスによって８ｍｍφの円盤状の電極を作製した。 (Comparative Example 3)
In Experimental Example 3, carbon black (“HS-100” manufactured by Denki Kagaku Kogyo Co., Ltd.), which was heat-treated in a vacuum at 3000 ° C. for 3 hours, was mixed with 15 mg and 15 mg of PTFE powder, and hot-pressed to a disk of 8 mmφ A shaped electrode was prepared.
＜電位－電流曲線の測定＞
　上記のようにして作製した実験例１及び比較例１～３の電極について、リチウムイオン電池用電解液中で電位走査し、電位－電流曲線を測定した。電解液は次のように調製した。すなわち、エチレンカーボネートとジメチルカーボネートとセバコニトリルとを質量比で２５：２５：５０となるように混合液を調製し、さらにＬｉＰＦ６を１ｍｏｌ／Ｌとなるように溶解した溶液を電解液とし、三極式電解セル容器に入れた。 <Measurement of potential-current curve>
The electrodes of Experimental Example 1 and Comparative Examples 1 to 3 produced as described above were subjected to potential scanning in an electrolyte for a lithium ion battery, and a potential-current curve was measured. The electrolytic solution was prepared as follows. That is, a mixed solution was prepared so that ethylene carbonate, dimethyl carbonate, and sebaconitrile were in a mass ratio of 25:25:50, and a solution in which LiPF 6 was dissolved to 1 mol / L was used as an electrolytic solution. Placed in an electrolytic cell container.
　電位－電流曲線の測定は、作用極として上記電極（面積０．５ｃｍ２）、対極として白金網、参照電極としてLi金属を用いた。掃引速度は５ｍＶ／ｓｅｃとした。 In the measurement of the potential-current curve, the above electrode (area 0.5 cm 2 ) was used as a working electrode, a platinum net as a counter electrode, and Li metal as a reference electrode. The sweep speed was 5 mV / sec.
　その結果、図８に示すように、ダイヤモンドライクカーボン粉末を用いた実験例１の電極では、比較例１のグラシーカーボン板電極とよりも広い電位窓を有していることが分かった。これに対して、カーボンブラックをそのまま電極とした比較例２では、電位窓が狭く、カーボンブラックを熱処理してグラファイト化した比較例３においても、電位窓が多少広がったものの、４．８Ｖ程度で５０μＡ／ｃｍ２となり、実験例１と比較して、電位窓が狭いことが分かった。 As a result, as shown in FIG. 8, it was found that the electrode of Experimental Example 1 using diamond-like carbon powder had a wider potential window than the glassy carbon plate electrode of Comparative Example 1. In contrast, in Comparative Example 2 in which carbon black was used as an electrode as it was, the potential window was narrow, and in Comparative Example 3 in which carbon black was heat-treated and graphitized, the potential window was slightly widened, but at about 4.8V. It was 50 μA / cm 2 , and it was found that the potential window was narrow compared to Experimental Example 1.
　以上の結果から、リチウム電池の正極活物質粉末に対して乾式めっき法によってダイヤモンドライクカーボンを付着させ、さらにこれにフッ素樹脂粉末を混合して成形した実施形態のリチウムイオン電池用正極は、リチウムイオン電池用の充電時に高い電位とされる正極においても、分解されることなく、溶媒を分解するおそれも少ないことが分かる。そして、この結果から、高い電位で充電反応が行われるエネルギー密度の高い正極活物質を有効に活用できることが分かった。 From the above results, the positive electrode for the lithium ion battery of the embodiment in which diamond-like carbon was attached to the positive electrode active material powder of the lithium battery by a dry plating method and further mixed with a fluororesin powder was formed by lithium ion It can be seen that even in a positive electrode that is set to a high potential during charging for a battery, the solvent is not likely to be decomposed without being decomposed. From this result, it was found that a positive electrode active material having a high energy density in which a charging reaction is performed at a high potential can be effectively used.
｛第３発明｝
（実施形態１）
　図９に示すように、アルミニウムやニッケルやチタンやオーステナイト系ステンレス（例えばＳＵＳ３０４、ＳＵＳ３１６、ＳＵＳ３０６Ｌ等）からなる基材２１を用意し、これに導電性ダイヤモンドライクカーボンからなる耐食性皮膜２２を形成する。 {Third invention}
(Embodiment 1)
As shown in FIG. 9, a base material 21 made of aluminum, nickel, titanium, or austenitic stainless steel (for example, SUS304, SUS316, SUS306L, etc.) is prepared, and a corrosion-resistant film 22 made of conductive diamond-like carbon is formed thereon.
　ダイヤモンドライクカーボン皮膜の形成方法としては特に限定はなく、例えば、CVD法、熱CVD、プラズマCVD（高周波、マイクロ波、直流等）、PVD法、真空蒸着法、イオンプレーティング（直流励起、高周波励起）法、スパッタ法（2極スパッタ、マグネトロンスパッタ、ECRスパッタ）、レーザーアブレーション法、イオンビームデポジション、イオン注入法等の手法を用いて形成することができる。 There is no particular limitation on the method of forming the diamond-like carbon film. For example, CVD method, thermal CVD, plasma CVD (high frequency, microwave, direct current, etc.), PVD method, vacuum deposition method, ion plating (direct current excitation, high frequency excitation) ) Method, sputtering method (bipolar sputtering, magnetron sputtering, ECR sputtering), laser ablation method, ion beam deposition, ion implantation method and the like.
　プラズマＣＶＤ法及びＰＶＤ法について、さらに具体的な手法を示せば、次のようになる。
（１）プラズマＣＶＤ法によるダイヤモンドライクカーボン膜の形成法
　チャンバー内に集電体基材を置き、アセチレンなどの炭化水素ガスをチャンバー内に導入し、電磁誘導によりプラズマ化して、気相合成した炭化水素を集電体基材表面に蒸着する。この方法によるダイヤモンドライクカーボン膜は、原料に水素が含まれるため、必ず水素が含まれる。この製法は集電体基材の温度をそれほど高くしなくてもよく、電極の配置により複雑形状でも均一に成膜しやすいこと、処理時間が比較的短いことなど工業的な利点が多い。
（２）ＰＶＤ法によるダイヤモンドライクカーボン膜の形成法
　ＰＶＤ法の一種であるスパッタリング法やイオンプレーティング法を用いることが好ましい。この方法は、黒鉛を真空中でイオンビームやアーク放電やグロー放電等にさらし、スパッタ現象によって飛び出した炭素原子を集電体基材に付着させる方法である。 A more specific method for the plasma CVD method and the PVD method is as follows.
(1) Method of forming diamond-like carbon film by plasma CVD method A collector base material is placed in the chamber, a hydrocarbon gas such as acetylene is introduced into the chamber, it is turned into plasma by electromagnetic induction, and carbonized by vapor phase synthesis. Hydrogen is deposited on the surface of the current collector substrate. The diamond-like carbon film by this method always contains hydrogen because the raw material contains hydrogen. This manufacturing method has many industrial advantages such as that the temperature of the current collector base material does not need to be so high, and it is easy to form a uniform film even in a complicated shape by the arrangement of electrodes, and the processing time is relatively short.
(2) Method for forming diamond-like carbon film by PVD method It is preferable to use a sputtering method or an ion plating method which is a kind of PVD method. This method is a method in which graphite is exposed to an ion beam, an arc discharge, a glow discharge, or the like in a vacuum, and carbon atoms ejected by a sputtering phenomenon are attached to a current collector substrate.
　そしてさらに、導電性の耐食性皮膜２２に存在する欠陥２３から露出する集電体基材２１の表面をフッ素化合物、酸素化合物、窒素化合物、炭素化合物及びリン化合物のうちの一種又は二種以上からなる不動態皮膜２４で覆う。例えば、リチウムイオン電池の電解液中でアルミニウムを高電位で処理すると、不動態皮膜が形成されることが知られており（2000年電気化学会. 秋季大会講演要旨集,p.17(2000)）、表面技術Vol.58,No.6, p337-341（2007））、この現象を利用すれば、耐食性皮膜の欠陥に不動態皮膜２４を形成させることができる。すなわち、導電性の耐食性皮膜２が形成された集電体基材２１を、リチウムイオン電池の電解質として用いられているＬｉＰＦ６やＬｉＢＦ４やＬｉＣｌＯ４の環状カーボネート及び／又は鎖状カーボネート溶液に浸し、充電に必要な電位（より望ましくは、参照電極（Ｌｉ／Ｌｉ＋）に対して６Ｖ～７Ｖ程度の電位）にすればよい。アルミニウムの場合は導電性の耐食性皮膜２に存在する欠陥２３で酸化され、塩がＬｉＰＦ６やＬｉＢＦ４の場合は、フッ素化合物もしくフッ素と酸素の複合化合物からなる不動態皮膜４が形成され、塩がＬｉＣｌＯ４の場合は、酸素化合物が形成される。こうして、本発明の集電体が得られる。 Further, the surface of the current collector base 21 exposed from the defects 23 present in the conductive corrosion-resistant film 22 is made of one or more of fluorine compounds, oxygen compounds, nitrogen compounds, carbon compounds and phosphorus compounds. Cover with a passive film 24. For example, it is known that a passive film is formed when aluminum is treated at high potential in the electrolyte of a lithium ion battery (2000 Electrochemical Society. Abstracts of Autumn Meeting, p.17 (2000) ), Surface technology Vol.58, No.6, p337-341 (2007)), this phenomenon can be used to form a passive film 24 on defects in the corrosion-resistant film. That is, the current collector base material 21 on which the conductive corrosion-resistant film 2 is formed is immersed in a cyclic carbonate and / or chain carbonate solution of LiPF 6 , LiBF 4 or LiClO 4 used as an electrolyte of a lithium ion battery. A potential required for charging (more desirably, a potential of about 6 V to 7 V with respect to the reference electrode (Li / Li + )) may be used. In the case of aluminum, it is oxidized by the defects 23 present in the conductive corrosion-resistant film 2, and when the salt is LiPF 6 or LiBF 4, a passive film 4 made of a fluorine compound or a composite compound of fluorine and oxygen is formed, When the salt is LiClO 4 , an oxygen compound is formed. Thus, the current collector of the present invention is obtained.
（実施形態２）
　実施形態１における導電性ダイヤモンドライクカーボンからなる耐食性皮膜の替わりに、グラッシーカーボンからなる導電性の耐食性皮膜を用いることもできる。このような耐食性皮膜は、例えば特開平１１－４３７７号公報に記載の方法によって形成することができる。すなわち、チタン等の金属からなる集電体基材をメタン、エタン、プロパンなどの炭化水素系ガスを含有する０．１～３０ｔｏｒｒ、４００～１１００℃の雰囲気内でプラズマ熱処理する。これにより、集電体基材表面にガラス状カーボン皮膜が形成される。 (Embodiment 2)
Instead of the corrosion-resistant film made of conductive diamond-like carbon in Embodiment 1, a conductive corrosion-resistant film made of glassy carbon can also be used. Such a corrosion-resistant film can be formed, for example, by the method described in JP-A-11-4377. That is, a current collector base material made of a metal such as titanium is subjected to plasma heat treatment in an atmosphere containing 0.1 to 30 torr and 400 to 1100 ° C. containing a hydrocarbon gas such as methane, ethane, or propane. Thereby, a glassy carbon film is formed on the surface of the current collector substrate.
（実施形態３）
　実施形態１における導電性ダイヤモンドライクカーボンからなる耐食性皮膜の替わりに、金や白金からなる導電性の耐食性皮膜を用いることもできる。この場合には、ＰＶＤ装置にターゲット電極として金や白金を設け、チャンバー内に集電体基材を置いて装置内を排気した後、イオン源となるガスを僅かに導入し、集電体基材に高負電圧を付与しつつ、放電を行う。これにより、イオン化した導入ガスは電圧により加速されてターゲット電極に衝突し、スパッタリング現象が生ずる。こうしてスパッタされた金や白金の粒子が集電体基材の表面に付着し、導電性の耐食性皮膜を形成することができる。 (Embodiment 3)
Instead of the corrosion-resistant film made of conductive diamond-like carbon in Embodiment 1, a conductive corrosion-resistant film made of gold or platinum can also be used. In this case, the PVD apparatus is provided with gold or platinum as a target electrode, a current collector base is placed in the chamber, the apparatus is evacuated, a gas serving as an ion source is slightly introduced, and the current collector base Discharge is performed while applying a high negative voltage to the material. As a result, the ionized introduced gas is accelerated by the voltage and collides with the target electrode, causing a sputtering phenomenon. The sputtered gold or platinum particles adhere to the surface of the current collector substrate, and a conductive corrosion-resistant film can be formed.
　以下本発明の集電体の発明の実施例について比較例と比較しつつ述べる。
（実施例１）
　実施例１では、プラズマＣＶＤ法によってアルミニウム電極の表面に導電性のダイヤモンドライクカーボン皮膜を形成した電極を作製し、リチウムイオン電池用電解液中で電位走査し、電位－電流曲線を測定した。電解液は次のように調製した。すなわち、エチレンカーボネートとジメチルカーボネートとセバコニトリルとを質量比で２５：２５：５０となるように混合液を調製し、さらにＬｉＰＦ６を１ｍｏｌ／Ｌとなるように溶解した溶液を電解液とし、三極式電解セル容器に入れた。 Examples of the current collector of the present invention will be described below in comparison with comparative examples.
Example 1
In Example 1, an electrode in which a conductive diamond-like carbon film was formed on the surface of an aluminum electrode by plasma CVD was prepared, and the potential was scanned in an electrolyte for a lithium ion battery, and a potential-current curve was measured. The electrolytic solution was prepared as follows. That is, a mixed solution was prepared so that ethylene carbonate, dimethyl carbonate, and sebaconitrile were in a mass ratio of 25:25:50, and a solution in which LiPF 6 was dissolved to 1 mol / L was used as an electrolytic solution. Placed in an electrolytic cell container.
　電気化学的測定は、作用極として電極（面積０．５ｃｍ２）、対極として白金網、参照電極としてＬｉ金属を用いた。測定は、参照極に対し３Ｖ～８Ｖの間を3回スキャンさせ、電位－電流曲線を測定した。掃引速度は５ｍＶ／ｓｅｃとした。 In the electrochemical measurement, an electrode (area 0.5 cm 2 ) was used as a working electrode, a platinum mesh was used as a counter electrode, and Li metal was used as a reference electrode. The measurement was performed by scanning the reference electrode three times between 3V and 8V, and measuring the potential-current curve. The sweep speed was 5 mV / sec.
（比較例１）
　比較例１では、アルミニウム基板に対して、実施例１と同様にリチウムイオン電池用電解液中で電位走査し、電位－電流曲線を測定した。さらには、電位走査を終えたアルミニウム電極について、ＸＰＳによる表面分析を行った。 (Comparative Example 1)
In Comparative Example 1, an aluminum substrate was subjected to potential scanning in an electrolytic solution for a lithium ion battery in the same manner as in Example 1, and a potential-current curve was measured. Furthermore, the surface analysis by XPS was performed about the aluminum electrode which finished the potential scan.
（比較例２）
　比較例１では、金電極に対して、実施例１と同様にリチウムイオン電池用電解液中で電位走査して電位－電流曲線を測定した。 (Comparative Example 2)
In Comparative Example 1, a potential-current curve was measured by scanning the potential of the gold electrode in the electrolyte for a lithium ion battery in the same manner as in Example 1.
（比較例３）
　比較例３では、白金電極に対して、実施例１と同様にリチウムイオン電池用電解液中で電位走査して電位－電流曲線を測定した。 (Comparative Example 3)
In Comparative Example 3, the potential-current curve was measured by scanning the potential of the platinum electrode in the electrolyte for a lithium ion battery in the same manner as in Example 1.
（比較例４）
　比較例４では、グラッシーカーボン電極に対して、実施例１と同様にリチウムイオン電池用電解液中で電位走査して電位－電流曲線を測定した。 (Comparative Example 4)
In Comparative Example 4, the potential-current curve was measured by scanning the potential of the glassy carbon electrode in the electrolyte for a lithium ion battery in the same manner as in Example 1.
＜評　価＞
　結果を図１０に示す。比較例１の電極（アルミニウム電極）の第１回目の掃引では４Ｖ位から酸化電流が流れ始め、電位が高くなるにつれて大きな酸化電流が流れたが、第２回目の掃引では、酸化電流はほとんど流れなかった。また、ＸＰＳの測定では、図１１（ｃ）に示すように、アルミニウムの表面にフッ素化合物、酸素化合物、窒素化合物、炭素化合物及びリン化合物が存在しており、比較例１の電極（アルミニウム電極）では、第１回目の掃引でこれらの化合物からなる不動態皮膜が形成されることが分かった。 <Evaluation>
The results are shown in FIG. In the first sweep of the electrode (aluminum electrode) of Comparative Example 1, an oxidation current began to flow from about 4 V, and a large oxidation current flowed as the potential increased. However, in the second sweep, the oxidation current almost flowed. There wasn't. Further, in the XPS measurement, as shown in FIG. 11C, a fluorine compound, an oxygen compound, a nitrogen compound, a carbon compound and a phosphorus compound are present on the surface of aluminum, and the electrode of Comparative Example 1 (aluminum electrode) Then, it turned out that the passive film which consists of these compounds is formed by the 1st sweep.
　これに対して、アルミニウム電極に導電性ダイヤモンドライクカーボンからなる皮膜を形成した実施例１の電極では、最初のスキャンにおいても６．４Ｖ位まではほとんど電流が流れず、７．２Ｖにおいても５０μＡ程度と小さく、２回目以降も同様に優れた耐食性を示すことが分かった。また、比較例２（金電極）、比較例３（白金電極）及び比較例４（グラッシーカーボン）の電位－電流曲線との比較から、実施例１の電極は、金や白金よりも耐食性に優れ、グラッシーカーボンと同程度の耐食性を示すことが分かった。 On the other hand, in the electrode of Example 1 in which the film made of conductive diamond-like carbon was formed on the aluminum electrode, almost no current flows up to about 6.4 V even in the first scan, and about 50 μA even at 7.2 V. It was found that the corrosion resistance was also excellent after the second time. Further, from comparison with the potential-current curves of Comparative Example 2 (gold electrode), Comparative Example 3 (platinum electrode), and Comparative Example 4 (glassy carbon), the electrode of Example 1 has better corrosion resistance than gold and platinum. It has been found that the glass has the same corrosion resistance as that of glassy carbon.
　また、さらに比較例１の電極（アルミニウム電極）における電位走査後のＸＰＳの測定結果と実施例１の電極の電位－電流曲線とから、以下のことが明らかとなった。
　すなわち、実施例１の電極では、上記リチウムイオン電池用電解液中で電位スキャンをさせれば、導電性ダイヤモンドライクカーボンからなる皮膜の欠陥から露出するアルミニウムにフッ素化合物や酸素化合物や窒素化合物や炭素化合物やリン化合物からなる不動態皮膜が覆うことで耐食性が確保され、さらには、導電性ダイヤモンドライクカーボンからなる皮膜で、電子伝導性も確保できる構造となる。 Further, from the XPS measurement results after potential scanning at the electrode (aluminum electrode) of Comparative Example 1 and the potential-current curve of the electrode of Example 1, the following became clear.
That is, in the electrode of Example 1, if a potential scan is performed in the above electrolyte solution for lithium ion batteries, fluorine compound, oxygen compound, nitrogen compound or carbon is exposed to aluminum exposed from defects in the film made of conductive diamond-like carbon. Corrosion resistance is ensured by covering with a passive film made of a compound or a phosphorus compound, and furthermore, a film made of conductive diamond-like carbon has a structure that can secure electron conductivity.
（実施例２）
　実施例２では、作用極側の電極基材として、プラズマＣＶＤ法によってニッケル板の表面にダイヤモンドライクカーボン皮膜を形成した電極を用い、電解質はＬｉＢＦ４を用いた。その他の測定条件については実験例１と同様であり、詳細な説明を省略する。 (Example 2)
In Example 2, as the electrode substrate on the working electrode side, an electrode in which a diamond-like carbon film was formed on the surface of a nickel plate by a plasma CVD method was used, and LiBF 4 was used as an electrolyte. The other measurement conditions are the same as in Experimental Example 1, and detailed description thereof is omitted.
（比較例５）
　比較例５では、ニッケル基板に対して、実施例２と同様にリチウムイオン電池用電解液中で電位走査して電位－電流曲線を測定した。さらには、掃引を終えたニッケル電極について、ＸＰＳによる表面分析を行った。 (Comparative Example 5)
In Comparative Example 5, the potential-current curve was measured by scanning the potential of the nickel substrate in the electrolyte for a lithium ion battery in the same manner as in Example 2. Furthermore, the surface analysis by XPS was performed about the nickel electrode which finished sweeping.
（比較例６）
　比較例６では、白金電極に対して、実施例２と同様にリチウムイオン電池用電解液中で電位走査して電位－電流曲線を測定した。 (Comparative Example 6)
In Comparative Example 6, the potential-current curve was measured by scanning the potential of the platinum electrode in the electrolyte for a lithium ion battery in the same manner as in Example 2.
（比較例７）
　比較例７では、グラッシーカーボン電極に対して、実施例２と同様にリチウムイオン電池用電解液中で電位走査して電位－電流曲線を測定した。 (Comparative Example 7)
In Comparative Example 7, the potential-current curve was measured by scanning the potential of the glassy carbon electrode in the electrolyte for a lithium ion battery in the same manner as in Example 2.
＜評　価＞
　その結果、図１２に示すように、比較例５の電極（ニッケル電極）の第１回目の掃引では４．６Ｖ位から酸化電流が流れ始め、電位が高くなるにつれて大きな酸化電流が流れたが、第２回目の掃引では、６Ｖ位までは酸化電流はほとんど流れなかった。また、ＸＰＳの測定から、図１１（ａ）に示すように、ニッケルの表面に酸素化合物、窒素化合物、炭素化合物及びリン化合物が存在しており、第１回目の掃引でこれらの化合物からなる不動態皮膜が形成されることが分かった。 <Evaluation>
As a result, as shown in FIG. 12, in the first sweep of the electrode of the comparative example 5 (nickel electrode), an oxidation current began to flow from about 4.6 V, and a large oxidation current flowed as the potential increased. In the second sweep, the oxidation current hardly flowed up to about 6V. Further, from XPS measurement, as shown in FIG. 11 (a), oxygen compound, nitrogen compound, carbon compound and phosphorus compound are present on the surface of nickel. It was found that a dynamic film was formed.
　これに対して、上記ニッケル電極に導電性ダイヤモンドライクカーボンからなる皮膜を形成した実施例２の電極では、図１２に示すように、最初のスキャンにおいても６．４Ｖ位まではほとんど電流が流れず、２回目のスキャンでは、さらに電位窓が０．２Ｖ程度高電位側へ広がった。また、比較例６（白金電極）の電位－電流曲線との比較により、実施例２の電極は、白金よりも優れた耐食性を示すことが分かった。 On the other hand, in the electrode of Example 2 in which a film made of conductive diamond-like carbon was formed on the nickel electrode, as shown in FIG. 12, almost no current flows up to about 6.4 V even in the first scan. In the second scan, the potential window further spreads to the high potential side by about 0.2V. Further, by comparing with the potential-current curve of Comparative Example 6 (platinum electrode), it was found that the electrode of Example 2 exhibited better corrosion resistance than platinum.
　また、比較例１の電極（アルミニウム電極）における電位走査後のＸＰＳの測定結果と実施例１の電極の電位－電流曲線とから、以下のことが明らかとなった。
　すなわち、ニッケル電極に導電性ダイヤモンドライクカーボンからなる皮膜を形成した電極を上記リチウムイオン電池用電解液中で電位スキャンをさせれば、導電性ダイヤモンドライクカーボンからなる皮膜の欠陥から露出するニッケルの表面に酸素化合物、窒素化合物、炭素化合物及びリン化合物からなる不動態皮膜が覆い、耐食性を飛躍的に高めることができる。 Further, from the XPS measurement results after potential scanning at the electrode (aluminum electrode) of Comparative Example 1 and the potential-current curve of the electrode of Example 1, the following became clear.
In other words, if a potential scan is performed in the electrolyte for a lithium ion battery on an electrode in which a film made of conductive diamond-like carbon is formed on a nickel electrode, the surface of nickel exposed from defects in the film made of conductive diamond-like carbon Further, a passive film made of an oxygen compound, a nitrogen compound, a carbon compound, and a phosphorus compound covers it, and the corrosion resistance can be drastically improved.
（実施例３）
　実施例３では、作用極側の電極基材としてプラズマＣＶＤ法によってチタン板の表面にダイヤモンドライクカーボン皮膜を形成した電極を用いた。その他の測定条件については実施例１と同様であり、詳細な説明を省略する。 (Example 3)
In Example 3, an electrode having a diamond-like carbon film formed on the surface of a titanium plate by a plasma CVD method was used as the electrode base on the working electrode side. The other measurement conditions are the same as in Example 1, and detailed description thereof is omitted.
（比較例８）
　比較例８では、チタン基板に対して、実施例１と同様にリチウムイオン電池用電解液中で電位走査して電位－電流曲線を測定した。さらには、掃引を終えたニッケル電極について、ＸＰＳによる表面分析を行った。 (Comparative Example 8)
In Comparative Example 8, the potential-current curve was measured by scanning the potential of the titanium substrate in the electrolyte for a lithium ion battery in the same manner as in Example 1. Furthermore, the surface analysis by XPS was performed about the nickel electrode which finished sweeping.
＜評　価＞
　その結果、図１３に示すように、比較例８の電極（チタン電極）の第１回目の掃引では４．６Ｖ位から酸化電流が流れ始め、電位が高くなるにつれて大きな酸化電流が流れたが、第２回目以降の掃引では、４．６Ｖを超えても電流の上昇は極めて小さく、７Ｖ以上においては、グラッシーカーボンよりも優れていた。
　また、ＸＰＳの測定から、図１１（ｂ）に示すように、チタンの表面に酸素化合物、窒素化合物、炭素化合物及びリン化合物が存在しており、第１回目の掃引で、チタン上にこれらの化合物からなる不動態皮膜が形成されることが分かった。 <Evaluation>
As a result, as shown in FIG. 13, in the first sweep of the electrode of Comparative Example 8 (titanium electrode), an oxidation current began to flow from about 4.6 V, and a large oxidation current flowed as the potential increased. In the second and subsequent sweeps, the increase in current was extremely small even when it exceeded 4.6 V, and it was superior to that of glassy carbon at 7 V or more.
Further, from the XPS measurement, as shown in FIG. 11B, oxygen compounds, nitrogen compounds, carbon compounds and phosphorus compounds are present on the surface of titanium. It was found that a passive film composed of the compound was formed.
　これに対して、上記チタン電極に導電性ダイヤモンドライクカーボンからなる皮膜を形成した実施例３の電極では、図１３に示すように、最初のスキャンにおいても７Ｖ位まではほとんど電流が流れず、２回目のスキャンでも、同程度の優れた耐食性を示すことが分かった。 On the other hand, in the electrode of Example 3 in which a film made of conductive diamond-like carbon was formed on the titanium electrode, as shown in FIG. In the second scan, it was found that the same level of corrosion resistance was exhibited.
　また、比較例８の電極（チタン電極）における電位走査後のＸＰＳの測定結果と実施例３の電極の電位－電流曲線とから、以下のことが明らかとなった。
　すなわち、チタン電極に導電性ダイヤモンドライクカーボンからなる皮膜を形成した電極を上記リチウムイオン電池用電解液中で電位スキャンをさせても、導電性ダイヤモンドライクカーボンからなる皮膜の欠陥から露出するチタンに酸素化合物、窒素化合物、炭素化合物及びリン化合物からなる不動態皮膜が覆い、耐食性を飛躍的に高めることができる。 Further, from the XPS measurement results after the potential scan of the electrode of Comparative Example 8 (titanium electrode) and the potential-current curve of the electrode of Example 3, the following became clear.
That is, even when an electrode having a film made of conductive diamond-like carbon formed on a titanium electrode is subjected to a potential scan in the electrolyte for lithium ion batteries, oxygen exposed to titanium exposed from defects in the film made of conductive diamond-like carbon. A passive film composed of a compound, a nitrogen compound, a carbon compound, and a phosphorus compound covers and can drastically enhance the corrosion resistance.
（実施例４～６）
　実施例４～６では、作用極側の電極基材として、プラズマＣＶＤ法によってオーステナイト系ステンレス（実施例４はＳＵＳ３０４、実施例５はＳＵＳ３１６、実施例６ではＳＵＳ３１６Ｌ）の表面にダイヤモンドライクカーボン皮膜を形成した電極を用いた。その他の測定条件については実施例１と同様であり、詳細な説明を省略する。 (Examples 4 to 6)
In Examples 4 to 6, a diamond-like carbon film was formed on the surface of an austenitic stainless steel (SUS304 in Example 4, SUS316 in Example 5 and SUS316L in Example 6) by plasma CVD as an electrode base on the working electrode side. The formed electrode was used. The other measurement conditions are the same as in Example 1, and detailed description thereof is omitted.
（比較例９～１１）
　比較例９～１１では、オーステナイト系ステンレス（比較例９はＳＵＳ３０４、比較例１０はＳＵＳ３１６、比較例１１はＳＵＳ３１６Ｌ）に対して、実施例１と同様にリチウムイオン電池用電解液中で電位走査して電位－電流曲線を測定した。 (Comparative Examples 9 to 11)
In Comparative Examples 9 to 11, the austenitic stainless steel (Comparative Example 9 is SUS304, Comparative Example 10 is SUS316, and Comparative Example 11 is SUS316L). The potential-current curve was measured.
　その結果、図１４に示すように、比較例９の電極（ＳＵＳ３０４電極）の第１回目の掃引では５．６Ｖ位から酸化電流が僅かに流れ、その後もほぼ一定の電流が継続して流れたが、第２回目以降の掃引では、電流は小さくなった。
　これに対して、ＳＵＳ３０４電極に導電性ダイヤモンドライクカーボンからなる皮膜を形成した実施例４の電極では、最初のスキャンにおいても７Ｖ位まではほとんど電流が流れず、２回目のスキャンでも、同程度の優れた耐食性を示すことが分かった。 As a result, as shown in FIG. 14, in the first sweep of the electrode of Comparative Example 9 (SUS304 electrode), an oxidation current slightly flowed from about 5.6 V, and a substantially constant current continued thereafter. However, the current decreased in the second and subsequent sweeps.
On the other hand, in the electrode of Example 4 in which a film made of conductive diamond-like carbon was formed on the SUS304 electrode, almost no current flows up to about 7 V even in the first scan, and the same level is obtained in the second scan. It was found that it exhibits excellent corrosion resistance.
　また、比較例１０の電極（ＳＵＳ３１６電極）及び比較例１１の電極（ＳＵＳ３１６Ｌ電極）についても、図１５及び図１６に示すように、第１回目の掃引では酸化電流が僅かに流れ、その後もほぼ一定の電流が継続して流れたが、第２回目以降の掃引では、電流は小さくなった。
　これに対して、ＳＵＳ３１６電極に導電性ダイヤモンドライクカーボンからなる皮膜を形成した実施例５の電極、及びＳＵＳ３１６Ｌ電極に導電性ダイヤモンドライクカーボンからなる皮膜を形成した実施例６の電極では、最初のスキャンにおいても７Ｖ位まではほとんど電流が流れず、２回目のスキャンでも、同程度の優れた耐食性を示すことが分かった。 As for the electrode of Comparative Example 10 (SUS316 electrode) and the electrode of Comparative Example 11 (SUS316L electrode), as shown in FIGS. 15 and 16, the oxidation current slightly flowed in the first sweep, and almost thereafter. A constant current continued to flow, but the current decreased in the second and subsequent sweeps.
On the other hand, in the electrode of Example 5 in which the film made of conductive diamond-like carbon was formed on the SUS316 electrode and the electrode of Example 6 in which the film made of conductive diamond-like carbon was formed on the SUS316L electrode, the first scan was performed. However, almost no current flows up to about 7V, and it was found that the second scan also showed the same excellent corrosion resistance.
（実施例７）
　実施例７では、実施例１と同様にしてアルミニウム基板上にダイヤモンドライクカーボンの皮膜を形成した後、表面をダイヤモンド製のガラス切りで意図的に傷をつけた電極を用いた。そして、この電極について、実施例１における電位－電流曲線の測定の場合と同様、エチレンカーボネートとジメチルカーボネートとセバコニトリルとを質量比で２５：２５：５０となるように混合液を調製し、さらにＬｉＰＦ６を１ｍｏｌ／Ｌとなるように溶解した溶液を電解液として電位－電流曲線の測定を行った。 (Example 7)
In Example 7, after forming a diamond-like carbon film on an aluminum substrate in the same manner as in Example 1, an electrode whose surface was intentionally scratched by cutting glass made of diamond was used. For this electrode, similarly to the measurement of the potential-current curve in Example 1, a mixed solution of ethylene carbonate, dimethyl carbonate, and sebaconitrile was prepared at a mass ratio of 25:25:50, and LiPF was further added. A potential-current curve was measured using a solution in which 6 was dissolved at 1 mol / L as an electrolyte.
　その結果、図１７に示すように、１回目の掃引では、２．３Ｖ（ｖｓ　Ｌｉ／Ｌｉ+）位から酸化電流が流れはじめ、３．３Ｖ（ｖｓ　Ｌｉ／Ｌｉ+）では５０μＡを超える電流が流れたのに対し、２回目の掃引では、５Ｖ（ｖｓ　Ｌｉ／Ｌｉ+）までほとんど電流は流れなかった。これは、１回目の掃引では、導電性ダイヤモンドライクカーボン皮膜の欠陥にある集電体基材のアルミニウムが電解液と反応して反応電流が流れて不動態皮膜が形成されるが、２回目の掃引では、欠陥部分が不動態で覆われるため、導電性ダイヤモンドライクカーボン上で反応する電流付近までアルミニウムとの反応電流はほとんど流れないことによると考えられる。このため、２回目の掃引では、アルミニウム基材の表面の多くが導電性ダイヤモンドライクカーボンで覆われているため、実施例１の電極のように、欠陥のない導電性ダイヤモンドライクカーボン皮膜が形成された電極の場合と同様の広い電位窓を有する電極となる。  As a result, as shown in FIG. 17, in the first sweep, 2.3V (vs Li / Li +) of the beginning oxidation current flows from, 3.3V current of more than (vs Li / Li +) at 50μA On the other hand, in the second sweep, almost no current flowed up to 5 V (vs Li / Li + ). In the first sweep, the current collector base aluminum, which is defective in the conductive diamond-like carbon film, reacts with the electrolytic solution and a reaction current flows to form a passive film. In the sweep, the defect portion is covered with a passive state, so that it is considered that the reaction current with aluminum hardly flows to the vicinity of the current that reacts on the conductive diamond-like carbon. For this reason, in the second sweep, since most of the surface of the aluminum base material is covered with conductive diamond-like carbon, a conductive diamond-like carbon film having no defects is formed as in the electrode of Example 1. The electrode has a wide potential window as in the case of the electrode.
（実施例８）
　実施例８の電極は、実施例３と同様にしてチタン基板上に欠陥のないダイヤモンドライクカーボンの皮膜を形成した電極である。 (Example 8)
The electrode of Example 8 is an electrode in which a diamond-like carbon film having no defect is formed on a titanium substrate in the same manner as in Example 3.
（比較例１２～２０）
　無処理のチタン電極を比較例１２、無処理のアルミニウム電極を比較例１３、無処理のニッケル電極を比較例１４、無処理のＳＵＳ３０４電極を比較例１５、無処理のＳＵＳ３１６電極を比較例１６、無処理のＳＵＳ３１６Ｌ電極を比較例１７、無処理のグラッシーカーボン電極を比較例１８、無処理の白金電極を比較例１９、無処理の金電極を比較例２０とした。 (Comparative Examples 12 to 20)
Comparative Example 12 for an untreated titanium electrode, Comparative Example 13 for an untreated aluminum electrode, Comparative Example 14 for an untreated nickel electrode, Comparative Example 15 for an untreated SUS304 electrode, Comparative Example 16 for an untreated SUS316 electrode, The untreated SUS316L electrode was designated as Comparative Example 17, the untreated glassy carbon electrode as Comparative Example 18, the untreated platinum electrode as Comparative Example 19, and the untreated gold electrode as Comparative Example 20.
＜評　価＞
　上記実施例８の電極及び比較例１２～２０の電極について、エチレンカーボネートとジメチルカーボネートとセバコニトリルとを質量比で２５：２５：５０となるように混合液を調製し、さらにＬｉＴＦＳＩを１ｍｏｌ／Ｌとなるように溶解した溶液を電解液として電位－電流曲線の測定を行った。
電位－電流曲線の測定を行った。 <Evaluation>
About the electrode of the said Example 8 and the electrodes of Comparative Examples 12-20, the liquid mixture was prepared so that ethylene carbonate, dimethyl carbonate, and a sebacononitrile might be set to 25:25:50 by mass ratio, and also LiTFSI was 1 mol / L. The potential-current curve was measured using the solution so dissolved as an electrolyte.
A potential-current curve was measured.
　その結果、図１８に示すように、電解質としてＬｉＴＦＳＩを用いたこの測定においては、比較例１２（チタン）、比較例１３（アルミニウム）、比較例１４（ニッケル）及び比較例１５～１７（オーステナイト系ステンレス）の電極は５Ｖ（ｖｓ　Ｌｉ／Ｌｉ+）以下の電位において大きな電流が流れ、電位窓は狭かった。
　これに対して、チタン上に欠陥のない導電性ダイヤモンドライクカーボン膜を形成した実施例８の電極では、電位窓は比較的広く、電位窓が６．５Ｖ（ｖｓ　Ｌｉ／Ｌｉ+）程度になった。
　以上の結果から、電位窓の狭いチタン、アルミニウム、ニッケル、オーステナイト系ステンレス基材はもちろんのこと、前記電位窓の狭い基材に限らずどのような基材でも導電性ダイヤモンドライクカーボンを欠陥がない状態で成膜すれば６．５Ｖ（ｖｓ　Ｌｉ／Ｌｉ+）の広い電位窓を確保できることが容易に推察できる。 As a result, as shown in FIG. 18, in this measurement using LiTFSI as the electrolyte, Comparative Example 12 (titanium), Comparative Example 13 (aluminum), Comparative Example 14 (nickel), and Comparative Examples 15 to 17 (austenitic series) A large current flowed through the electrode of stainless steel at a potential of 5 V (vs Li / Li + ) or less, and the potential window was narrow.
On the other hand, in the electrode of Example 8 in which a conductive diamond-like carbon film having no defect is formed on titanium, the potential window is relatively wide and the potential window is about 6.5 V (vs Li / Li + ). It was.
From the above results, there is no defect in conductive diamond-like carbon in any base material, not limited to the base material with a narrow potential window, as well as a titanium, aluminum, nickel, and austenitic stainless steel base material with a narrow potential window. It can be easily assumed that a wide potential window of 6.5 V (vs Li / Li + ) can be secured if the film is formed in this state.
　また、比較例１８（グラッシーカーボン）、比較例１９（白金）、比較例２０（金）の電極の電位窓は、比較例１２（チタン）、比較例１３（アルミニウム）、比較例１４（ニッケル）及び比較例１５～１７（オーステナイト系ステンレス）よりも電位窓が広く、比較例１８（グラッシーカーボン）で６．３Ｖ（ｖｓ　Ｌｉ／Ｌｉ+）程度、比較例１９（白金）では５．９Ｖ（ｖｓ　Ｌｉ／Ｌｉ+）程度、比較例２０（金）では５．８Ｖ（ｖｓ　Ｌｉ／Ｌｉ+）程度となった。
　以上の結果から、電位窓の狭いチタン、アルミニウム、ニッケル及びオーステナイト系ステンレス等、電位窓の狭い電極であっても、導電性ダイヤモンドライクカーボンと同様、グラッシーカーボンや白金や金を、欠陥がない状態で皮膜形成させれば、広い電位窓を確保できることが容易に推察できる。
　なお、成膜する導電性ダイヤモンドライクカーボン、グラッシーカーボン、白金および金と基材となる電極との密着性が不足する場合には、基材温度を上げて成膜したり、中間層をいれたりしてもよい。例えば導電性ダイヤモンドライクカーボンの中間層としては、Ｔｉ，Ｓｉ，ＳｉＣ、ＴｉＣ，ＣｒやＮｂが挙げられる（ＤＬＣハンドブック、（株）ＮＴＳ発行,ｐ598）。また、Ａｕ皮膜形成の場合は、Ｎｉを中間層として用いることにより、密着性が向上することがよく知られている。 Further, the potential windows of the electrodes of Comparative Example 18 (Glassy Carbon), Comparative Example 19 (Platinum), and Comparative Example 20 (Gold) are Comparative Example 12 (Titanium), Comparative Example 13 (Aluminum), and Comparative Example 14 (Nickel). In addition, the potential window is wider than those of Comparative Examples 15 to 17 (austenitic stainless steel), about 6.3 V (vs Li / Li + ) in comparative example 18 (glassy carbon), and 5.9 V (vs in comparative example 19 (platinum)). Li / Li +) or so, it was the Comparative example 20 (gold) 5.8V (vs Li / Li + ) degree.
From the above results, even with electrodes with narrow potential windows such as titanium, aluminum, nickel and austenitic stainless steel with narrow potential windows, glassy carbon, platinum and gold are in a state of no defects, just like conductive diamond-like carbon. It can be easily inferred that a wide potential window can be secured if a film is formed by (1).
If the adhesion between the conductive diamond-like carbon, glassy carbon, platinum and gold to be deposited and the electrode serving as the substrate is insufficient, the substrate temperature may be raised, and an intermediate layer may be inserted. May be. For example, the intermediate layer of conductive diamond-like carbon includes Ti, Si, SiC, TiC, Cr and Nb (DLC Handbook, published by NTS, p598). In the case of Au film formation, it is well known that adhesion is improved by using Ni as an intermediate layer.
（比較例２１及び比較例２２）
　比較例２１の電極は、実施例１と同様にしてアルミニウム基板上にダイヤモンドライクカーボンの皮膜を形成した後、表面をダイヤモンド製のガラス切りで意図的に傷をつけた電極である。
　また、比較例２２の電極は、実施例２と同様にしてニッケル基板上にダイヤモンドライクカーボンの皮膜を形成した後、表面をダイヤモンド製のガラス切りで意図的に傷をつけた電極である。 (Comparative Example 21 and Comparative Example 22)
The electrode of Comparative Example 21 was an electrode in which a diamond-like carbon film was formed on an aluminum substrate in the same manner as in Example 1, and then the surface was intentionally damaged by cutting glass made of diamond.
The electrode of Comparative Example 22 is an electrode in which a diamond-like carbon film was formed on a nickel substrate in the same manner as in Example 2, and then the surface was intentionally damaged by cutting glass made of diamond.
　上記のようにして作成した比較例２１及び比較例２２の電極について、エチレンカーボネートとジメチルカーボネートとセバコニトリルとを質量比で２５：２５：５０となるように混合液を調製し、さらにＬｉＴＦＳＩを１ｍｏｌ／Ｌとなるように溶解した溶液を電解液として電位－電流曲線の測定を行った。
　また、比較のため実施例８（チタン基板上に欠陥の無いダイヤモンドライクカーボンの皮膜を形成した電極）並びにＡｌ、Ｔｉ及びＮｉからなる電極についても、同様にして電位－電流曲線の測定を行った。 For the electrodes of Comparative Example 21 and Comparative Example 22 prepared as described above, a mixed solution was prepared so that ethylene carbonate, dimethyl carbonate, and sebaconitrile were in a mass ratio of 25:25:50, and LiTFSI was 1 mol / mol. The potential-current curve was measured using the solution dissolved so as to be L as the electrolytic solution.
For comparison, the potential-current curve was also measured in the same manner for Example 8 (electrode on which a diamond-like carbon film having no defect was formed on a titanium substrate) and an electrode made of Al, Ti, and Ni. .
　その結果、図１９に示すように、欠陥のない実施例８（チタン基板上に欠陥の無いダイヤモンドライクカーボンの皮膜を形成した電極）では、６Ｖ（ｖｓ　Ｌｉ／Ｌｉ+）位まではほとんど電流は流れないのに対し、比較例２１の電極（すなわち、アルミニウム基板上にダイヤモンドライクカーボンの皮膜を形成した後、傷をつけた電極）では、アルミニウム電極と同様、４．１Ｖ（ｖｓ　Ｌｉ／Ｌｉ+）付近より急激な微量の腐食電流が流れ始め（比較例２１）。そして、最終的には導電性ダイヤモンドライクカーボン上で反応電流が流れ始める６．３Ｖ（ｖｓ　Ｌｉ／Ｌｉ+）付近から急激に大きな電流が流れた。
　また、比較例２２の電極（すなわち、ニッケル基板上にダイヤモンドライクカーボンの皮膜を形成した後、傷をつけた電極）においても、ニッケル電極と同じ５Ｖ（ｖｓ　Ｌｉ／Ｌｉ+）付近より腐食電流が流れ始めた。
　以上の結果から、導電性ダイヤモンドライクカーボン膜に欠陥があり、その欠陥において基材が電解液と触れる場合は、基材の腐食が発生する電位と同じ電位付近で腐食電流が流れ始めることが分かった。また、グラッシーカーボンや白金や金の皮膜が形成されていても、その皮膜に欠陥がある場合には、比較例２１や比較例２２の電極と同様に、基材の腐食が発生する電位付近で腐食電流が流れ始めることが容易に推察できる。 As a result, as shown in FIG. 19, in Example 8 with no defect (an electrode in which a diamond-like carbon film having no defect is formed on a titanium substrate), the current is almost up to about 6 V (vs Li / Li + ). On the other hand, the electrode of Comparative Example 21 (that is, the electrode that was damaged after forming a diamond-like carbon film on the aluminum substrate) was 4.1 V (vs Li / Li + ) as in the case of the aluminum electrode. ) A very small amount of corrosion current starts to flow from the vicinity (Comparative Example 21). Finally, a large current suddenly flowed from around 6.3 V (vs Li / Li + ) where the reaction current began to flow on the conductive diamond-like carbon.
Further, in the electrode of Comparative Example 22 (that is, the electrode that was damaged after forming a diamond-like carbon film on the nickel substrate), the corrosion current was higher than the vicinity of 5 V (vs Li / Li + ) as in the nickel electrode. Began to flow.
From the above results, it can be seen that when the conductive diamond-like carbon film has a defect and the substrate touches the electrolyte at that defect, the corrosion current starts to flow around the same potential as the potential for corrosion of the substrate. It was. Further, even if a glassy carbon, platinum, or gold film is formed, if the film is defective, similar to the electrodes of Comparative Examples 21 and 22, near the potential at which corrosion of the substrate occurs. It can be easily guessed that the corrosion current starts to flow.
（実施例９）
　実施例９の電極は、実施例７の電極（すなわち、実施例１と同様にしてアルミニウム基板上にダイヤモンドライクカーボンの皮膜を形成した後、表面をダイヤモンド製のガラス切りで意図的に傷をつけた電極）について、さらにエチレンカーボネートとジメチルカーボネートとセバコニトリルとを質量比で２５：２５：５０となるように混合液を調製し、さらにＬｉＰＦ６を１ｍｏｌ／Ｌとなるように溶解した溶液を電解液として、電位－電流曲線の測定を行った電位掃引後の電極である。 Example 9
The electrode of Example 9 is the electrode of Example 7 (that is, after a diamond-like carbon film was formed on an aluminum substrate in the same manner as in Example 1, the surface was intentionally damaged by cutting glass made of diamond. In addition, a mixed solution of ethylene carbonate, dimethyl carbonate, and sebaconitrile is prepared at a mass ratio of 25:25:50, and a solution in which LiPF 6 is dissolved at 1 mol / L is used as an electrolytic solution. The electrode after potential sweep in which the potential-current curve was measured.
　こうして得られた実施例９の電極について、エチレンカーボネートとジメチルカーボネートとセバコニトリルとを質量比で２５：２５：５０となるように混合液を調製し、さらにＬｉＴＦＳＩを１ｍｏｌ／Ｌとなるように溶解した溶液を電解液として、電位－電流曲線の測定を行った。また、比較のために何らの表面処理も行っていないアルミニウム電極についても、同様に電位－電流曲線の測定を行った。 For the electrode of Example 9 obtained in this way, a mixed solution was prepared so that ethylene carbonate, dimethyl carbonate, and sebaconitrile were in a mass ratio of 25:25:50, and further LiTFSI was dissolved so as to be 1 mol / L. Using the solution as an electrolytic solution, the potential-current curve was measured. For comparison, a potential-current curve was also measured for an aluminum electrode that had not been subjected to any surface treatment.
　その結果、図２０に示すように、実施例９の電極では、チタン基板上に欠陥のない導電性ダイヤモンドライクカーボン皮膜を形成した実施例８の電極と同等のレベルの電位窓となった。これに対して、何らの表面処理も行っていないアルミニウム電極では、４．１Ｖ（ｖｓ　Ｌｉ／Ｌｉ+）付近から、急激に腐食電流が流れ出した。
　以上の結果は、次のように説明できる。すなわち、実施例９の電極のように、導電性ダイヤモンドライクカーボン上に皮膜に欠陥があったとしても、エチレンカーボネートとジメチルカーボネートとセバコニトリルとを質量比で２５：２５：５０となるように混合液を調製し、さらにＬｉＰＦ６を１ｍｏｌ／Ｌとなるように溶解した溶液を電解液として、電位掃引を行うことにより、その欠陥部分に優れた耐食性を示す不動態皮膜を形成することができる。また、欠陥以外の部分は導電性ダイヤモンドライクカーボンからなる皮膜で覆われているため、電極反応が可能な部分は、実質的に導電性ダイヤモンドライクカーボン膜部分だけになる。このため、実施例９の電極においても、実施例８（すなわちアルミニウムに欠陥のない導電性ダイヤモンドライクカーボンの皮膜を形成した電極）と同様、優れた耐食性に優れ、広い電位窓を有する電極となるのである。
　また、前記の実施例９における欠陥を有する導電性ダイヤモンドライクの代わりに、成膜物質として、グラッシーカーボン、白金もしくは金を使用した場合も、成膜物質であるグラッシーカーボンや白金や金と同程度の電位窓とすることができる。 As a result, as shown in FIG. 20, the electrode of Example 9 had a potential window at a level equivalent to that of the electrode of Example 8 in which a conductive diamond-like carbon film having no defect was formed on the titanium substrate. On the other hand, in the aluminum electrode not subjected to any surface treatment, a corrosion current suddenly flowed out from around 4.1 V (vs Li / Li + ).
The above results can be explained as follows. That is, as in the electrode of Example 9, even when the film was defective on the conductive diamond-like carbon, the mixed liquid was such that ethylene carbonate, dimethyl carbonate, and sebaconitrile were in a mass ratio of 25:25:50. In addition, by performing potential sweep using a solution in which LiPF 6 is dissolved to 1 mol / L as an electrolytic solution, a passive film exhibiting excellent corrosion resistance can be formed on the defective portion. Further, since the portion other than the defect is covered with a film made of conductive diamond-like carbon, the portion capable of electrode reaction is substantially only the conductive diamond-like carbon film portion. For this reason, the electrode of Example 9 also has excellent corrosion resistance and an electrode having a wide potential window, similar to Example 8 (that is, an electrode formed with a conductive diamond-like carbon film having no defects in aluminum). It is.
In addition, when glassy carbon, platinum, or gold is used as a film forming material instead of the conductive diamond-like material having defects in the ninth embodiment, the same degree as glassy carbon, platinum, or gold as the film forming material is used. Potential window.
　以上の結果から、２次電池の電解質としてＬｉＰＦ６やＬｉＢＦ４を用いる場合、電極基材がアルミニウムの場合は、不動態皮膜が形成され、優れた耐食性を示すことが分かる。
　また、２次電池の電解質としてＬｉＴＦＳＩを用いた場合であり、アルミニウム基材上の皮膜（例えば導電性ダイヤモンドライクカーボン皮膜やグラッシーカーボンや白金皮膜や金皮膜）に欠陥があったとしても、その電極を電解質としてＬｉＰＦ６やＬｉＢＦ４を含む電解液で予め電位掃引しておけば、欠陥部分のアルミにウムに不動態皮膜が形成され、欠陥からの腐食の進行を食い止めることができ、皮膜素材と同等の優れた耐食性を有する電極となる。 From the above results, it can be seen that when LiPF 6 or LiBF 4 is used as the electrolyte of the secondary battery, when the electrode base material is aluminum, a passive film is formed and exhibits excellent corrosion resistance.
In addition, when LiTFSI is used as an electrolyte of a secondary battery, even if a film (for example, a conductive diamond-like carbon film, a glassy carbon, a platinum film, or a gold film) on an aluminum substrate has a defect, the electrode If the potential is swept in advance with an electrolyte containing LiPF 6 or LiBF 4 as an electrolyte, a passive film is formed on the aluminum in the defective portion, and the progress of corrosion from the defect can be stopped. The electrode has the same excellent corrosion resistance.
＜リチウムイオン電池の作製＞
　上述した実施形態の集電体を用いてリチウムイオン電池を作製することができる。すなわち、図２１に示すように、ステンレス等からなる電池容器３５にセパレータ３６を挟んで両側に正極活物質を含む正極３７と、カーボン等からなる負極３８とを配設させる。そして、さらに正極３７にアルミニウムを基材とする集電体３９を接触させ、その一端を電池容器３５から外に突出させる。また、負極３８にニッケルあるいはチタンを基材とする集電体４０を接触させ、その一端を電池容器５から外に突出させる。そして、内部にリチウムイオン電池用の電解液を入れる。集電体３９及び４０は、基材に導電性ダイヤモンドライクカーボン皮膜が形成されており、さらにその導電性ダイヤモンドライクカーボンやグラッシーカーボンやＰｔやＡｕからなる皮膜の欠陥にはアルミニウムやニッケルあるいはチタンのフッ素化合物からなる不動態皮膜で覆われているため、導電性を有し、かつ、耐食性に極めて優れたものとなる。不動態皮膜は、用いる電解質や溶媒により異なるが、フッ素化合物、酸素化合物、窒素化合物、炭素化合物やリン化合物のうち一種もしくはその複合物で形成されている。 <Production of lithium ion battery>
A lithium ion battery can be manufactured using the current collector of the embodiment described above. That is, as shown in FIG. 21, a positive electrode 37 containing a positive electrode active material and a negative electrode 38 made of carbon or the like are disposed on both sides with a separator 36 sandwiched between a battery container 35 made of stainless steel or the like. Further, a current collector 39 based on aluminum is brought into contact with the positive electrode 37, and one end of the current collector 39 is protruded from the battery container 35. Further, a current collector 40 based on nickel or titanium is brought into contact with the negative electrode 38, and one end of the current collector 40 is protruded from the battery container 5. And the electrolyte solution for lithium ion batteries is put in an inside. In the current collectors 39 and 40, a conductive diamond-like carbon film is formed on a base material, and defects of the film made of conductive diamond-like carbon, glassy carbon, Pt, and Au are made of aluminum, nickel, or titanium. Since it is covered with a passive film made of a fluorine compound, it has conductivity and is extremely excellent in corrosion resistance. The passive film differs depending on the electrolyte and solvent used, but is formed of one or a composite of fluorine compounds, oxygen compounds, nitrogen compounds, carbon compounds and phosphorus compounds.
　以下ニトリルを含有するリチウムイオン電池用電解液を具体化した実施例についてさらに詳細に述べる。 Hereinafter, examples embodying the electrolytic solution for lithium ion batteries containing nitrile will be described in more detail.
（実施例１）
　実施例１では、有機溶媒としてアジポニトリルと、エチレンカーボネート（ＥＣ）と、ジメチルカーボネート（ＤＭＣ）とを容量比で５０：２５：２５の割合で混合した溶媒を用い、これにリチウム塩としてＬｉＰＦ6（六フッ化リン酸リチウム）を０．０５ｍｏｌ／Ｌとなるように溶解させてリチウムイオン電池用電解液とした。 Example 1
In Example 1, a solvent in which adiponitrile, ethylene carbonate (EC), and dimethyl carbonate (DMC) were mixed at a volume ratio of 50:25:25 was used as the organic solvent, and LiPF 6 ( Lithium hexafluorophosphate) was dissolved at 0.05 mol / L to obtain an electrolyte for a lithium ion battery.
（比較例１）
　比較例１では、有機溶媒としてエチレンカーボネート５０体積％、ジメチルカーボネート５０体積％の混合溶媒を用い、これにリチウム塩としてＬｉＰＦ6を１ｍｏｌ／Ｌとなるように溶解させてリチウムイオン電池用電解液とした。 (Comparative Example 1)
In Comparative Example 1, a mixed solvent of 50% by volume of ethylene carbonate and 50% by volume of dimethyl carbonate was used as the organic solvent, and LiPF 6 was dissolved as a lithium salt at a concentration of 1 mol / L. did.
（実施例２～９）
　実施例２～９では溶媒を、各種ニトリル：エチレンカーボネート：ジメチルカーボネート＝５０：２５：２５(容量比)とし、この混合溶媒に電解質をＬｉＰＦ6（六フッ化リン酸リチウム）を１ｍｏｌ／Ｌとなるように溶解させたものをリチウムイオン電池用電解液とした（ただし、ニトリル化合物をオキシジプロピオニトリルにした実施例６は、ＬｉＰＦ6を０．５ｍｏｌ／Ｌとした）。
各実施例に用いたニトリルの種類は以下のとおりである。
　実施例１　アジポニトリルＮＣ（ＣＨ２）４ＣＮ
　実施例２　スクシノニトリルＮＣ（ＣＨ２）２ＣＮ
　実施例３　セバコニトリルＮＣ（ＣＨ２）８ＣＮ
　実施例４　ドデカンジニトリルＮＣ（ＣＨ２）１０ＣＮ
　実施例５　２－メチルグルタロニトリルＮＣＣＨ（ＣＨ３）ＣＨ２ＣＨ２ＣＮ
　実施例６　オキシジプロピオニトリルＮＣＣＨ２ＣＨ２-Ｏ-ＣＨ２ＣＨ２ＣＮ
　実施例７　３－メトキシプロピオニトリルＣＨ３-Ｏ-ＣＨ２ＣＨ２ＣＮ
　実施例８　シアノ酢酸メチルＮＣＣＨ２ＣＯＯＣＨ３
　実施例９　シアノ酢酸ブチルＮＣＣＨ２ＣＯＯ（ＣＨ２）３ＣＨ３ (Examples 2 to 9)
In Examples 2 to 9, the solvent was various nitrile: ethylene carbonate: dimethyl carbonate = 50: 25: 25 (volume ratio), and the electrolyte was LiPF 6 (lithium hexafluorophosphate) at 1 mol / L in this mixed solvent. The so-dissolved solution was used as an electrolyte solution for a lithium ion battery (however, in Example 6 in which the nitrile compound was oxydipropionitrile, LiPF 6 was 0.5 mol / L).
The types of nitriles used in each example are as follows.
Example 1 Adiponitrile NC (CH 2 ) 4 CN
Example 2 Succinonitrile NC (CH 2 ) 2 CN
Example 3 Sevacononitrile NC (CH 2 ) 8 CN
Example 4 Dodecanedinitrile NC (CH 2 ) 10 CN
Example 5 2-Methylglutaronitrile NCCH (CH 3 ) CH 2 CH 2 CN
Example 6-oxy dipropionate nitrile NCCH 2 CH 2 -O-CH 2 CH 2 CN
Example 7 3-Methoxypropionitrile CH 3 —O—CH 2 CH 2 CN
Example 8 Methyl cyanoacetate NCCH 2 COOCH 3
Example 9 cyanoacetate butyl NCCH 2 COO (CH 2) 3 CH 3
－評価－
（電位－電流曲線の測定）
　以上のようにして調製した実施例１～９及び比較例１のリチウムイオン電池用電解液について、電位－電流曲線を測定した。測定にはポテンシオガルバノスタットを用い、作用極にはグラッシーカーボンを用い、対極には白金線を用いた。また、参照電極は(Ag/Ag+)または(Li/Li+)を用いた。測定にあたっては、正側及び負側に数回スキャンさせた後、自然電位から正方向、あるいは負方向に５ｍＶ／秒の速度で電位の掃引を行い、電位－電流曲線を測定した。結果を図２２、図２３及び図２４に示す。 -Evaluation-
(Measurement of potential-current curve)
With respect to the lithium ion battery electrolytes of Examples 1 to 9 and Comparative Example 1 prepared as described above, potential-current curves were measured. A potentiogalvanostat was used for measurement, glassy carbon was used for the working electrode, and a platinum wire was used for the counter electrode. As the reference electrode, (Ag / Ag +) or (Li / Li +) was used. In the measurement, after scanning the positive side and the negative side several times, the potential was swept from the natural potential in the positive direction or in the negative direction at a rate of 5 mV / sec, and the potential-current curve was measured. The results are shown in FIG. 22, FIG. 23 and FIG.
　その結果、図２２に示すように、実施例１の電解液の電位窓は、Li電位(Li/Li+)に対し6.9V（電位窓の判断基準は５０μＡ／ｃｍ２とした。以下同様）となった。これに対して、エチレンカーボネートとジメチルカーボネートの混合溶媒を用いた比較例１の電位窓は、図２４６に示すように５．２Vであり、実施例１の電解液の電位窓は、比較例１の電解液に比べて、正側に大きく広がっていることが分かった。この結果から、実施例１の電解液を用いれば、充電のための電位が５．２Vを超えた領域に存在するような高電位酸化還元正極活物質をリチウムイオン電池の正極活物質として利用できることとなり、起電力及びエネルギー密度が高く、容量の大きなリチウムイオン電池とすることができる。例えば、比較例１の電解液では、Ｌｉ２ＣｏＰＯ４ＦやＬｉ２ＮｉＰＯ４Ｆの酸化還元電位でも有機溶媒が電気分解を起こし、これらの正極酸化物質を利用することができないのに対し、実施例１の電解液を用いれば、Ｌｉ２ＣｏＰＯ４ＦやＬｉ２ＮｉＰＯ４Ｆを正極活物質として利用できるだけでなく、例えば、ＬｉＣｏＰＯ４，ＬｉＮｉＰＯ４等も利用することができる。 As a result, as shown in FIG. 22, the potential window of the electrolytic solution of Example 1 was 6.9 V with respect to the Li potential (Li / Li + ) (the judgment criterion of the potential window was 50 μA / cm 2, and so on). It became. On the other hand, the potential window of Comparative Example 1 using a mixed solvent of ethylene carbonate and dimethyl carbonate is 5.2 V as shown in FIG. 246, and the potential window of the electrolytic solution of Example 1 is Comparative Example 1. Compared to the electrolyte solution of, it was found that it spreads greatly on the positive side. From this result, when the electrolytic solution of Example 1 is used, a high potential redox positive electrode active material that exists in a region where the potential for charging exceeds 5.2 V can be used as the positive electrode active material of the lithium ion battery. Thus, a lithium ion battery having high electromotive force and energy density and large capacity can be obtained. For example, in the electrolytic solution of Comparative Example 1, the organic solvent undergoes electrolysis even at the redox potential of Li 2 CoPO 4 F or Li 2 NiPO 4 F, and these positive electrode oxidizing substances cannot be used. If the electrolytic solution of Example 1 is used, not only Li 2 CoPO 4 F or Li 2 NiPO 4 F can be used as the positive electrode active material, but also LiCoPO 4 , LiNiPO 4, etc. can be used.
　また、図２３に示すように、実施例２～９の電解液においても、実施例１と同様、いずれも比較例１の電解液と比較して、電位窓が正方向に広がることが分かった。これらの結果から、エチレンカーボネート及びジメチルカーボネートに、さらに鎖式飽和炭化水素化合物の両末端にニトリル基が結合した鎖式飽和炭化水素ジニトリル化合物（実施例１～５）、鎖式エーテル化合物の末端の少なくとも一つにニトリル基が結合した鎖式エーテルニトリル化合物（実施例６，７）及びシアノ酢酸エステルのうち少なくとも一つのニトリル化合物（実施例８，９）を加えることによって、溶媒が高い電位まで分解することなく安定に存在できることが分かった。特に電位窓が大きく広がったのは、ニトリル化合物として鎖式飽和炭化水素化合物の両末端にニトリル基が結合した鎖式飽和炭化水素ジニトリル化合物を用いた実施例１～５であり、分枝を有する実施例５においても大きく電位窓が正方向に広がることが分かった。また、オキシジプロピオニトリルＮＣＣＨ２ＣＨ２-Ｏ-ＣＨ２ＣＨ２ＣＮを用いた実施例６においても、大きく電位窓が正方向に広がることが分かった。 Further, as shown in FIG. 23, in the electrolyte solutions of Examples 2 to 9, it was found that the potential window widened in the positive direction as compared with the electrolyte solution of Comparative Example 1 as in Example 1. . From these results, ethylene carbonate and dimethyl carbonate, chain saturated hydrocarbon dinitrile compounds in which nitrile groups are bonded to both ends of the chain saturated hydrocarbon compound (Examples 1 to 5), the terminal ether chain compound By adding a chain ether nitrile compound (Examples 6 and 7) having at least one nitrile group bonded thereto and at least one nitrile compound (Examples 8 and 9) among cyanoacetic acid esters, the solvent is decomposed to a high potential. It was found that it can exist stably without doing. In particular, the potential window greatly widened in Examples 1 to 5 in which a chain saturated hydrocarbon dinitrile compound in which a nitrile group was bonded to both ends of a chain saturated hydrocarbon compound was used as a nitrile compound, which has branches. Also in Example 5, it was found that the potential window greatly spreads in the positive direction. Also, in Example 6 using oxydipropionitrile NCCH 2 CH 2 —O—CH 2 CH 2 CN, it was found that the potential window greatly expanded in the positive direction.
（実施例１０～１７）
　実施例１０～１７では溶媒を、各種ニトリル：エチレンカーボネート：ジエチルカーボネート＝５０：２５：２５(容量比)とし、この混合溶媒に電解質をＬｉＰＦ6（六フッ化リン酸リチウム）を１ｍｏｌ／Ｌとなるように溶解させたものをリチウムイオン電池用電解液とした（ただし、ニトリル化合物をグルタロニトリルにした実施例１０では、ＬｉＰＦ6（六フッ化リン酸リチウム）を０．５ｍｏｌ／Ｌとした）。
各実施例に用いたニトリルの種類は以下のとおりである。
　実施例１０　グルタロニトリルＮＣ（ＣＨ２）３ＣＮ
　実施例１１　セバコニトリルＮＣ（ＣＨ２）８ＣＮ
　実施例１２　ドデカンジニトリルＮＣ（ＣＨ２）１０ＣＮ
　実施例１３　２－メチルグルタロニトリルＮＣＣＨ（ＣＨ３）ＣＨ２ＣＨ２ＣＮ
　実施例１４　オキシジプロピオニトリルＮＣＣＨ２ＣＨ２-Ｏ-ＣＨ２ＣＨ２ＣＮ
　実施例１５　３－メトキシプロピオニトリルＣＨ３-Ｏ-ＣＨ２ＣＨ２ＣＮ
　実施例１６　シアノ酢酸メチルＮＣＣＨ２ＣＯＯＣＨ３
　実施例１７　シアノ酢酸ブチルＮＣＣＨ２ＣＯＯ（ＣＨ２）３ＣＨ３ (Examples 10 to 17)
In Examples 10 to 17, the solvent was various nitrile: ethylene carbonate: diethyl carbonate = 50: 25: 25 (volume ratio), and the electrolyte was LiPF 6 (lithium hexafluorophosphate) at 1 mol / L in this mixed solvent. What was dissolved in this way was used as the electrolyte solution for lithium ion batteries (however, in Example 10 in which the nitrile compound was glutaronitrile, LiPF 6 (lithium hexafluorophosphate) was 0.5 mol / L. ).
The types of nitriles used in each example are as follows.
Example 10 Glutaronitrile NC (CH 2 ) 3 CN
Example 11 sebaconitrile NC (CH 2) 8 CN
Example 12 Dodecanedinitrile NC (CH 2 ) 10 CN
Example 13 2-Methylglutaronitrile NCCH (CH 3 ) CH 2 CH 2 CN
Example 14 oxy dipropionate nitrile NCCH 2 CH 2 -O-CH 2 CH 2 CN
Example 15 3-Methoxy-propionitrile CH 3 -O-CH 2 CH 2 CN
Example 16 methyl cyanoacetate NCCH 2 COOCH 3
Example 17 cyanoacetate butyl NCCH 2 COO (CH 2) 3 CH 3
（比較例２）
　比較例２では、有機溶媒としてエチレンカーボネート：ジエチルカーボネート＝５０：５０(容量比)の混合溶媒を用い、これにリチウム塩としてＬｉＰＦ6を１ｍｏｌ／Ｌとなるように溶解させてリチウムイオン電池用電解液とした。 (Comparative Example 2)
In Comparative Example 2, a mixed solvent of ethylene carbonate: diethyl carbonate = 50: 50 (volume ratio) was used as the organic solvent, and LiPF 6 was dissolved as a lithium salt in an amount of 1 mol / L to perform electrolysis for a lithium ion battery. Liquid.
－評価－
（電位－電流曲線の測定）
　実施例１０～１７及び比較例２の電解液について、前述の方法と同様にして電位－電流曲線を測定した。結果を図２５に示す。
　この図から、実施例１０～１７の電解液では、比較例２の電解液と比較して、電位窓が正方向に広がることが分かった。この結果から、エチレンカーボネート及びジエチルカーボネートを溶媒として用いた場合においても、エチレンカーボネート及びジメチルカーボネートを溶媒として用いた場合（すなわち実施例１～９の場合）と同様、鎖式飽和炭化水素化合物の両末端にニトリル基が結合した鎖式飽和炭化水素ジニトリル化合物、鎖式エーテル化合物の末端の少なくとも一つにニトリル基が結合した鎖式エーテルニトリル化合物及びシアノ酢酸エステルのうち少なくとも一つのニトリル化合物を加えることによって、溶媒が高い電位まで安定に存在することが分かった。特に電位窓が大きく広がったのは、ニトリル化合物として鎖式飽和炭化水素化合物の両末端にニトリル基が結合した鎖式飽和炭化水素ジニトリル化合物を用いた実施例１０～１３であり、分枝を有する実施例１３においても大きく電位窓が正方向に広がることが分かった。また、鎖式エーテル化合物の末端の少なくとも一つにニトリル基が結合した鎖式エーテルニトリル化合物を用いた実施例１４及び実施例１５においても、大きく電位窓が正方向に広がることが分かった。 -Evaluation-
(Measurement of potential-current curve)
For the electrolytes of Examples 10 to 17 and Comparative Example 2, potential-current curves were measured in the same manner as described above. The results are shown in FIG.
From this figure, it was found that in the electrolytic solutions of Examples 10 to 17, the potential window spreads in the positive direction as compared with the electrolytic solution of Comparative Example 2. From this result, even when ethylene carbonate and diethyl carbonate were used as solvents, both of the chain saturated hydrocarbon compounds were the same as when ethylene carbonate and dimethyl carbonate were used as solvents (that is, in the case of Examples 1 to 9). Add at least one nitrile compound among a chain saturated hydrocarbon dinitrile compound having a nitrile group bonded to the terminal, a chain ether nitrile compound having a nitrile group bonded to at least one terminal of the chain ether compound, and a cyanoacetate ester. It was found that the solvent exists stably up to a high potential. In particular, the potential window greatly widened in Examples 10 to 13 in which a chain saturated hydrocarbon dinitrile compound in which a nitrile group was bonded to both ends of a chain saturated hydrocarbon compound was used as a nitrile compound, which has branches. Also in Example 13, it was found that the potential window greatly expanded in the positive direction. Also, in Example 14 and Example 15 using a chain ether nitrile compound in which a nitrile group was bonded to at least one end of the chain ether compound, it was found that the potential window greatly expanded in the positive direction.
（実施例１８～２５）
　実施例１８～２５では溶媒を、各種ニトリル：γ－ブチロラクトン：ジメチルカーボネート＝５０：２５：２５(容量比)とし、この混合溶媒に電解質をＬｉＰＦ6（六フッ化リン酸リチウム）を１ｍｏｌ／Ｌとなるように溶解させたものをリチウムイオン電池用電解液とした。また、ニトリルとしてアジポニトリルを用いた実施例では、LiPF6を0.5mol/Lとした。
各実施例に用いたニトリルの種類は以下のとおりである。
　実施例１８　グルタロニトリルＮＣ（ＣＨ２）３ＣＮ
　実施例１９　アジポニトリルＮＣ（ＣＨ２）４ＣＮ
　実施例２０　セバコニトリルＮＣ（ＣＨ２）８ＣＮ
　実施例２１　ドデカンジニトリルＮＣ（ＣＨ２）１０ＣＮ
　実施例２２　２－メチルグルタロニトリルＮＣＣＨ（ＣＨ３）ＣＨ２ＣＨ２ＣＮ
　実施例２３　オキシジプロピオニトリルＮＣＣＨ２ＣＨ２-Ｏ-ＣＨ２ＣＨ２ＣＮ
　実施例２４　シアノ酢酸メチルＮＣＣＨ２ＣＯＯＣＨ３
　実施例２５　シアノ酢酸ブチルＮＣＣＨ２ＣＯＯ（ＣＨ２）３ＣＨ３ (Examples 18 to 25)
In Examples 18 to 25, the solvent was various nitrile: γ-butyrolactone: dimethyl carbonate = 50: 25: 25 (volume ratio), and the electrolyte was LiPF 6 (lithium hexafluorophosphate) at 1 mol / L in this mixed solvent. What was dissolved so that it might become was set as the electrolyte solution for lithium ion batteries. In the example using adiponitrile as the nitrile, LiPF 6 was 0.5 mol / L.
The types of nitriles used in each example are as follows.
Example 18 Glutaronitrile NC (CH 2 ) 3 CN
Example 19 adiponitrile NC (CH 2) 4 CN
Example 20 sebaconitrile NC (CH 2) 8 CN
Example 21 dodecane dinitrile NC (CH 2) 10 CN
Example 22 2-methylglutaronitrile NCCH (CH 3) CH 2 CH 2 CN
Example 23 oxy dipropionate nitrile NCCH 2 CH 2 -O-CH 2 CH 2 CN
Example 24 methyl cyanoacetate NCCH 2 COOCH 3
Example 25 cyanoacetate butyl NCCH 2 COO (CH 2) 3 CH 3
（比較例３）
　比較例３では、有機溶媒としてγ－ブチロラクトン：ジメチルカーボネート＝５０：５０(容量比)の混合溶媒を用い、これにリチウム塩としてＬｉＰＦ6を１ｍｏｌ／Ｌとなるように溶解させてリチウムイオン電池用電解液とした。 (Comparative Example 3)
In Comparative Example 3, a mixed solvent of γ-butyrolactone: dimethyl carbonate = 50: 50 (volume ratio) was used as the organic solvent, and LiPF 6 was dissolved as a lithium salt at 1 mol / L to be used for a lithium ion battery. An electrolyte was used.
－評価－
（電位－電流曲線の測定）
　実施例１８～２５及び比較例３の電解液について、前述の方法と同様にして電位－電流曲線を測定した。結果を図２６に示す。
　この図から、実施例１８～２５の電解液においても、比較例３の電解液と比較して、電位窓が正方向に大きく広がることが分かった。この結果から、環状カーボネートであるエチレンカーボネートに替えて、ジメチルカーボネート及び環状エステルであるγ－ブチロラクトンを溶媒として用いた場合においても、鎖式飽和炭化水素化合物の両末端にニトリル基が結合した鎖式飽和炭化水素ジニトリル化合物を加えることによって、溶媒が高い電位まで安定に存在することが分かった。また、鎖式飽和炭化水素ジニトリル化合物のうち、直鎖分子である実施例１８～２１のみならず、分枝を有する実施例２２においても大きく電位窓が正方向に広がることが分かった。さらに、鎖式エーテル化合物の両末端にニトリル基が結合した鎖式エーテルニトリル化合物を用いた実施例２３や、シアノ酢酸エステルを用いた実施例２４，２５においても、大きく電位窓が正方向に広がることが分かった。 -Evaluation-
(Measurement of potential-current curve)
For the electrolyte solutions of Examples 18 to 25 and Comparative Example 3, potential-current curves were measured in the same manner as described above. The results are shown in FIG.
From this figure, it was found that also in the electrolyte solutions of Examples 18 to 25, the potential window greatly expanded in the positive direction as compared with the electrolyte solution of Comparative Example 3. From this result, even when dimethyl carbonate and cyclic ester γ-butyrolactone were used as a solvent instead of cyclic carbonate ethylene carbonate, a chain formula in which a nitrile group was bonded to both ends of the chain saturated hydrocarbon compound. It was found that by adding the saturated hydrocarbon dinitrile compound, the solvent exists stably to a high potential. Further, it was found that, among the chain-type saturated hydrocarbon dinitrile compounds, not only in Examples 18 to 21 which are linear molecules but also in Example 22 having branches, the potential window greatly spreads in the positive direction. Further, in Example 23 using a chain ether nitrile compound in which a nitrile group is bonded to both ends of the chain ether compound, and in Examples 24 and 25 using cyanoacetate, the potential window is greatly widened in the positive direction. I understood that.
（実施例２６～３１）
　実施例２６～３１では溶媒を、各種ニトリル：ジメチルカーボネート＝５０：５０(容量比)とし、この混合溶媒に電解質をＬｉＰＦ6（六フッ化リン酸リチウム）を１ｍｏｌ／Ｌ(実施例３０、３１では０．１ｍｏｌ／Ｌ)となるように溶解させたものをリチウムイオン電池用電解液とした。各実施例に用いたニトリルの種類は以下のとおりである。
　実施例２６　グルタロニトリルＮＣ（ＣＨ２）３ＣＮ
　実施例２７　セバコニトリルＮＣ（ＣＨ２）８ＣＮ
　実施例２８　ドデカンジニトリルＮＣ（ＣＨ２）１０ＣＮ
　実施例２９　２－メチルグルタロニトリルＮＣＣＨ（ＣＨ３）ＣＨ２ＣＨ２ＣＮ
　実施例３０　オキシジプロピオニトリルＮＣＣＨ２ＣＨ２-Ｏ-ＣＨ２ＣＨ２ＣＮ
　実施例３１　シアノ酢酸メチルＮＣＣＨ２ＣＯＯＣＨ３ (Examples 26 to 31)
In Examples 26 to 31, the solvent was various nitriles: dimethyl carbonate = 50: 50 (volume ratio), and the electrolyte was LiPF 6 (lithium hexafluorophosphate) 1 mol / L (Examples 30 and 31). In this case, an electrolyte solution for a lithium ion battery was dissolved so as to be 0.1 mol / L). The types of nitriles used in each example are as follows.
Example 26 glutaronitrile NC (CH 2) 3 CN
Example 27 sebaconitrile NC (CH 2) 8 CN
Example 28 Dodecanedinitrile NC (CH 2 ) 10 CN
Example 29 2-methylglutaronitrile NCCH (CH 3) CH 2 CH 2 CN
Example 30 oxy dipropionate nitrile NCCH 2 CH 2 -O-CH 2 CH 2 CN
Example 31 methyl cyanoacetate NCCH 2 COOCH 3
（比較例４）
　比較例４では、有機溶媒としてジメチルカーボネートにリチウム塩としてＬｉＰＦ6を１ｍｏｌ／Ｌとなるように溶解させてリチウムイオン電池用電解液とした。 (Comparative Example 4)
In Comparative Example 4, LiPF 6 as a lithium salt was dissolved in dimethyl carbonate as an organic solvent so as to be 1 mol / L to obtain an electrolytic solution for a lithium ion battery.
－評価－
（電位－電流曲線の測定）
　実施例２６～３１及び比較例４の電解液について、前述の方法と同様にして電位－電流曲線を測定した。結果を図２７に示す。
　この図から、溶媒としてニトリル化合物以外にジメチルカーボネートを単独で加えた実施例２６～３１の電解液では、ジメチルカーボネートを単独溶媒とした比較例３の電解液と比較して、電位窓が正方向に広がることが分かった。また、鎖式飽和炭化水素化合物の両末端にニトリル基が結合した鎖式飽和炭化水素ジニトリル化合物を加えることによって（実施例２６～２９）、溶媒が高い電位まで安定に存在することが分かった。さらには、鎖式飽和炭化水素ジニトリル化合物のうち、直鎖分子である実施例２６～２８のみならず、分枝を有する実施例２９においても大きく電位窓が正方向に広がることが分かった。さらに、鎖式エーテル化合物の両末端にニトリル基が結合した鎖式エーテルニトリル化合物を用いた実施例３０でも電位窓が大きく広がり、シアノ酢酸エステルを用いた実施例３１では、電位窓が広がった。 -Evaluation-
(Measurement of potential-current curve)
For the electrolyte solutions of Examples 26 to 31 and Comparative Example 4, potential-current curves were measured in the same manner as described above. The results are shown in FIG.
From this figure, in the electrolytic solutions of Examples 26 to 31 in which dimethyl carbonate alone was added in addition to the nitrile compound as the solvent, the potential window was positive in comparison with the electrolytic solution of Comparative Example 3 in which dimethyl carbonate was the sole solvent. I understood that it spreads. It was also found that the solvent was stably present up to a high potential by adding a chain saturated hydrocarbon dinitrile compound having nitrile groups bonded to both ends of the chain saturated hydrocarbon compound (Examples 26 to 29). Further, it has been found that the potential window greatly expands in the positive direction not only in Examples 26 to 28 which are linear molecules among the chain saturated hydrocarbon dinitrile compounds but also in Example 29 having branches. Furthermore, in Example 30 using a chain ether nitrile compound in which a nitrile group was bonded to both ends of the chain ether compound, the potential window was greatly expanded, and in Example 31 using cyanoacetate, the potential window was expanded.
（実施例３２，３３）
　実施例３２，３３では溶媒を、各種ニトリル：プロピレンカーボネート＝５０：５０(容量比)とし、この混合溶媒に電解質をＬｉＰＦ6（六フッ化リン酸リチウム）を１ｍｏｌ／Ｌとなるように溶解させたものをリチウムイオン電池用電解液とした。各実施例に用いたニトリルの種類は以下のとおりである。
　実施例３２　セバコニトリルＮＣ（ＣＨ２）８ＣＮ
　実施例３３　ドデカンジニトリルＮＣ（ＣＨ２）１０ＣＮ (Examples 32 and 33)
In Examples 32 and 33, the solvent was various nitrile: propylene carbonate = 50: 50 (volume ratio), and the electrolyte was dissolved in this mixed solvent so that LiPF 6 (lithium hexafluorophosphate) was 1 mol / L. This was used as an electrolyte for lithium ion batteries. The types of nitriles used in each example are as follows.
Example 32 sebaconitrile NC (CH 2) 8 CN
Example 33 dodecane dinitrile NC (CH 2) 10 CN
（比較例５）
　比較例５では、有機溶媒としてプロピレンカーボネートにリチウム塩としてＬｉＰＦ6を１ｍｏｌ／Ｌとなるように溶解させてリチウムイオン電池用電解液とした。 (Comparative Example 5)
In Comparative Example 5, an electrolyte solution for a lithium ion battery was prepared by dissolving LiPF 6 as a lithium salt in propylene carbonate as an organic solvent so as to be 1 mol / L.
－評価－
（電位－電流曲線の測定）
　実施例３２，３３及び比較例５の電解液について、前述の方法と同様にして電位－電流曲線を測定した。結果を図２８に示す。
　この図から、溶媒としてニトリル化合物以外にプロピレンカーボネートを単独で加えた実施例３２，３３の電解液では、プロピレンカーボネートを単独溶媒とした比較例５の電解液と比較して、電位窓が正方向に大きく広がることが分かった。また、鎖式飽和炭化水素化合物の両末端にニトリル基が結合した鎖式飽和炭化水素ジニトリル化合物を加えることによって、溶媒が高い電位まで安定に存在することが分かった。 -Evaluation-
(Measurement of potential-current curve)
For the electrolytic solutions of Examples 32 and 33 and Comparative Example 5, potential-current curves were measured in the same manner as described above. The results are shown in FIG.
From this figure, in the electrolytic solutions of Examples 32 and 33 in which propylene carbonate alone was added in addition to the nitrile compound as the solvent, the potential window was positive in comparison with the electrolytic solution of Comparative Example 5 in which propylene carbonate was the sole solvent. It was found that it spreads greatly. It was also found that the solvent was stably present up to a high potential by adding a chain saturated hydrocarbon dinitrile compound having nitrile groups bonded to both ends of the chain saturated hydrocarbon compound.
（実施例３４～３６）
　実施例３４～３６では溶媒を、各種ニトリル：γ－ブチロラクトン＝５０：５０(容量比)とし、この混合溶媒に電解質をＬｉＰＦ6（六フッ化リン酸リチウム）を１ｍｏｌ／Ｌとなるように溶解させたものをリチウムイオン電池用電解液とした。各実施例に用いたニトリルの種類は以下のとおりである。
　実施例３４　グルタロニトリルＮＣ（ＣＨ２）３ＣＮ
　実施例３５　セバコニトリルＮＣ（ＣＨ２）８ＣＮ
　実施例３６　ドデカンジニトリルＮＣ（ＣＨ２）１０ＣＮ (Examples 34 to 36)
In Examples 34 to 36, the solvent was various nitriles: γ-butyrolactone = 50: 50 (volume ratio), and the electrolyte was dissolved in LiPF 6 (lithium hexafluorophosphate) at 1 mol / L in this mixed solvent. This was used as an electrolyte for a lithium ion battery. The types of nitriles used in each example are as follows.
Example 34 glutaronitrile NC (CH 2) 3 CN
Example 35 sebaconitrile NC (CH 2) 8 CN
Example 36 dodecane dinitrile NC (CH 2) 10 CN
（比較例６）
　比較例６では、有機溶媒としてγ－ブチロラクトンにリチウム塩としてＬｉＰＦ6を０．１ｍｏｌ／Ｌとなるように溶解させてリチウムイオン電池用電解液とした。 (Comparative Example 6)
In Comparative Example 6, a lithium ion battery electrolyte solution was prepared by dissolving LiPF 6 as a lithium salt in γ-butyrolactone as an organic solvent so as to have a concentration of 0.1 mol / L.
－評価－
（電位－電流曲線の測定）
　実施例３４～３６及び比較例６の電解液について、前述の方法と同様にして電位－電流曲線を測定した。結果を図２９に示す。
　この図から、溶媒としてニトリル化合物以外にγ－ブチロラクトンを単独で加えた実施例３４～３６の電解液では、γ－ブチロラクトンを単独溶媒とした比較例５の電解液と比較して、電位窓が正方向に大きく広がることが分かった。また、鎖式飽和炭化水素化合物の両末端にニトリル基が結合した鎖式飽和炭化水素ジニトリル化合物を加えることによって、溶媒が高い電位まで安定に存在することが分かった。 -Evaluation-
(Measurement of potential-current curve)
For the electrolytic solutions of Examples 34 to 36 and Comparative Example 6, potential-current curves were measured in the same manner as described above. The results are shown in FIG.
From this figure, the electrolytic solution of Examples 34 to 36 in which γ-butyrolactone alone was added as a solvent in addition to the nitrile compound had a potential window as compared with the electrolytic solution of Comparative Example 5 in which γ-butyrolactone was the sole solvent. It turns out that it spreads greatly in the positive direction. It was also found that the solvent was stably present up to a high potential by adding a chain saturated hydrocarbon dinitrile compound having nitrile groups bonded to both ends of the chain saturated hydrocarbon compound.
（実施例３７～３９）
　実施例３７～３９では溶媒を、各種ニトリル：エチレンカーボネート：γ－ブチロラクトン＝５０：２５：２５(容量比)とし、この混合溶媒に電解質をＬｉＰＦ6（六フッ化リン酸リチウム）を１ｍｏｌ／Ｌとなるように溶解させたものをリチウムイオン電池用電解液とした。各実施例に用いたニトリルの種類は以下のとおりである。
　実施例３７　セバコニトリルＮＣ（ＣＨ２）８ＣＮ
　実施例３８　２－メチルグルタロニトリルＮＣＣＨ（ＣＨ３）ＣＨ２ＣＨ２ＣＮ
　実施例３９　オキシジプロピオニトリルＮＣＣＨ２ＣＨ２-Ｏ-ＣＨ２ＣＨ２ＣＮ (Examples 37 to 39)
In Examples 37 to 39, the solvent was various nitrile: ethylene carbonate: γ-butyrolactone = 50: 25: 25 (volume ratio), and the electrolyte was LiPF 6 (lithium hexafluorophosphate) at 1 mol / L in this mixed solvent. What was dissolved so that it might become was set as the electrolyte solution for lithium ion batteries. The types of nitriles used in each example are as follows.
Example 37 sebaconitrile NC (CH 2) 8 CN
Example 38 2-methylglutaronitrile NCCH (CH 3) CH 2 CH 2 CN
Example 39 oxy dipropionate nitrile NCCH 2 CH 2 -O-CH 2 CH 2 CN
（比較例７）
　比較例７では、有機溶媒としてエチレンカーボネート：γ－ブチロラクトン＝５０：５０(容量比)にリチウム塩としてＬｉＰＦ6を１ｍｏｌ／Ｌとなるように溶解させてリチウムイオン電池用電解液とした。 (Comparative Example 7)
In Comparative Example 7, an electrolyte solution for a lithium ion battery was prepared by dissolving LiPF 6 as a lithium salt in ethylene carbonate: γ-butyrolactone = 50: 50 (volume ratio) as an organic solvent so as to be 1 mol / L.
－評価－
（電位－電流曲線の測定）
　実施例３７～３９及び比較例７の電解液について、前述の方法と同様にして電位－電流曲線を測定した。結果を図３０に示す。
　この図から、溶媒としてニトリル化合物以外に環状カーボネートであるエチレンカーボネートと、環状エステルであるγ－ブチロラクトンとを溶媒として加えた実施例３７～３９の電解液では、ニトリル化合物を入れない比較例７の電解液と比較して、電位窓が正方向及び負方向に大きく広がることが分かった。また、鎖式飽和炭化水素化合物の両末端にニトリル基が結合した鎖式飽和炭化水素ジニトリル化合物を加えることによって、溶媒が高い電位まで安定に存在することが分かった。さらには、鎖式飽和炭化水素ジニトリル化合物のうち、直鎖分子である実施例３７のみならず、分枝を有する実施例３８においても大きく電位窓が正方向及び負方向に広がることが分かった。さらに、鎖式エーテル化合物の両末端にニトリル基が結合した鎖式エーテルニトリル化合物を用いた実施例３９でも電位窓が大きく正負方向に広がった。 -Evaluation-
(Measurement of potential-current curve)
For the electrolytic solutions of Examples 37 to 39 and Comparative Example 7, potential-current curves were measured in the same manner as described above. The results are shown in FIG.
From this figure, in the electrolytic solutions of Examples 37 to 39 in which ethylene carbonate, which is a cyclic carbonate, and γ-butyrolactone, which is a cyclic ester, are added as solvents in addition to the nitrile compound, the nitrile compound is not added. It was found that the potential window spreads greatly in the positive and negative directions as compared with the electrolyte. It was also found that the solvent was stably present up to a high potential by adding a chain saturated hydrocarbon dinitrile compound having nitrile groups bonded to both ends of the chain saturated hydrocarbon compound. Furthermore, it was found that, among the chain-type saturated hydrocarbon dinitrile compounds, not only in Example 37, which is a linear molecule, but also in Example 38 having branches, the potential window greatly spreads in the positive and negative directions. Further, in Example 39 using a chain ether nitrile compound in which a nitrile group was bonded to both ends of the chain ether compound, the potential window was greatly widened in the positive and negative directions.
（実施例４０～４４）
　実施例４０～４４では溶媒を、セバコニトリル（実施例４２ではアジポニトリル）：エチレンカーボネート：ジメチルカーボネート＝５０：２５：２５(容量比)とし、この混合溶媒に各種電解質を１ｍｏｌ／Ｌとなるように溶解させたものをリチウムイオン電池用電解液とした。各実施例に用いた電解質の種類は以下のとおりである。
　実施例４０　ＬｉＰＦ6
　実施例４１　ＬｉＴＦＳＩ
　実施例４２　ＬｉＴＦＳＩ
　実施例４３　ＬｉＢＦ４
　実施例４４　ＬｉＢＥＴＩ (Examples 40 to 44)
In Examples 40 to 44, the solvent was sebacononitrile (adiponitrile in Example 42): ethylene carbonate: dimethyl carbonate = 50: 25: 25 (volume ratio), and various electrolytes were dissolved in this mixed solvent so as to be 1 mol / L. This was used as an electrolyte for a lithium ion battery. The types of electrolyte used in each example are as follows.
Example 40 LiPF 6
Example 41 LiTFSI
Example 42 LiTFSI
Example 43 LiBF 4
Example 44 LiBETI
（実施例４５）
　実施例４５では、有機溶媒としてセバコニトリルと、エチレンカーボネート（ＥＣ）と、ジメチルカーボネート（ＤＭＣ）とを容量比で５０：２５：２５の割合で混合した溶媒を用い、これにリチウム塩としてＬｉＰＦ6（六フッ化リン酸リチウム）を０．０５ｍｏｌ／Ｌ、ＬｉＴＦＳＩ（リチウムビス（トリフルオロメタンスルホニル）イミド）を１．０ｍｏｌ／Ｌとなるように溶解させてリチウムイオン電池用電解液とした。 (Example 45)
In Example 45, a solvent in which sebacononitrile, ethylene carbonate (EC), and dimethyl carbonate (DMC) were mixed at a volume ratio of 50:25:25 was used as the organic solvent, and LiPF 6 ( Lithium hexafluorophosphate) was dissolved at 0.05 mol / L and LiTFSI (lithium bis (trifluoromethanesulfonyl) imide) was dissolved at 1.0 mol / L to obtain an electrolyte for a lithium ion battery.
（実施例４６）
　実施例４６では、有機溶媒としてシアノ酢酸ブチルと、エチレンカーボネート（ＥＣ）と、ジメチルカーボネート（ＤＭＣ）とを容量比で５０：２５：２５の割合で混合した溶媒を用い、これにリチウム塩としてＬｉＴＦＳＩ（リチウムビス（トリフルオロメタンスルホニル）イミド）を１．０ｍｏｌ／Ｌとなるように溶解させてリチウムイオン電池用電解液とした。 (Example 46)
In Example 46, a solvent in which butyl cyanoacetate, ethylene carbonate (EC), and dimethyl carbonate (DMC) were mixed at a volume ratio of 50:25:25 as an organic solvent, and LiTFSI as a lithium salt was used. (Lithium bis (trifluoromethanesulfonyl) imide) was dissolved at 1.0 mol / L to obtain an electrolytic solution for a lithium ion battery.
（実施例４７）
　実施例４７では、有機溶媒としてシアノ酢酸ブチルと、エチレンカーボネート（ＥＣ）と、ジメチルカーボネート（ＤＭＣ）とを容量比で５０：２５：２５の割合で混合した溶媒を用い、これにリチウム塩としてＬｉＢＦ４（四フッ化ホウ酸リチウム）を１．０ｍｏｌ／Ｌとなるように溶解させてリチウムイオン電池用電解液とした。 (Example 47)
In Example 47, a solvent obtained by mixing butyl cyanoacetate, ethylene carbonate (EC), and dimethyl carbonate (DMC) in a volume ratio of 50:25:25 as an organic solvent, and LiBF as a lithium salt was used. 4 (lithium tetrafluoroborate) was dissolved at 1.0 mol / L to obtain an electrolyte for a lithium ion battery.
（比較例８～１０）
　比較例８～１０では、比較例１におけるリチウム塩であるＬｉＰＦ6の替わりに、各種リチウム塩を添加した。すなわち、有機溶媒としてエチレンカーボネート：ジメチルカーボネート＝５０：５０(容量比)に各種リチウム塩（比較例８ではＬｉＴＦＳＩ、比較例９ではＬｉＢＦ４、比較例１０ではＬｉＢＥＴＩ）を１ｍｏｌ／Ｌとなるように溶解させてリチウムイオン電池用電解液とした。 (Comparative Examples 8 to 10)
In Comparative Examples 8 to 10, various lithium salts were added in place of LiPF 6 which is the lithium salt in Comparative Example 1. That is, various lithium salts (LiTFSI in Comparative Example 8, LiBF 4 in Comparative Example 9, LiBETI in Comparative Example 10) at 1 mol / L as an organic solvent, ethylene carbonate: dimethyl carbonate = 50: 50 (volume ratio). It was made to melt | dissolve and it was set as the electrolyte solution for lithium ion batteries.
－評価－
（電位－電流曲線の測定）
　実施例４０～４４、比較例１及び比較例８～１０の電解液について、前述の方法と同様にして電位－電流曲線を測定した。結果を図３１に示す。またこの図から求めた、電流密度が５０μＡ／ｃｍ２となるときの電位の値を表１に示す。
　この図３１及び表１から、溶媒としてニトリル化合物以外に環状カーボネートであるエチレンカーボネートと鎖状カーボネートであるジメチルカーボネートとを溶媒として加えた実施例４０～４４の電解液では、電解質の種類によらず、ニトリル化合物を入れない比較例１及び比較例８～１０の電解液と比較して、電位窓が正方向に大きく広がることが分かった。
　また、実施例４５の電解液の電位窓は６．６Ｖ（図３２参照）、実施例４６の電解液の電位窓は５．４Ｖ（図３３参照）、実施例４７の電解液の電位窓は６．１Ｖ（図３４参照）となり、いずれも正側に広がっていることが分かった。 -Evaluation-
(Measurement of potential-current curve)
For the electrolytic solutions of Examples 40 to 44, Comparative Example 1 and Comparative Examples 8 to 10, potential-current curves were measured in the same manner as described above. The results are shown in FIG. In addition, Table 1 shows the value of the potential obtained from this figure when the current density is 50 μA / cm 2 .
From FIG. 31 and Table 1, in the electrolyte solutions of Examples 40 to 44 in which ethylene carbonate, which is a cyclic carbonate, and dimethyl carbonate, which is a chain carbonate, are added as solvents in addition to the nitrile compound, the electrolytes are not limited to the kind of the electrolyte. It was found that the potential window greatly expanded in the positive direction as compared with the electrolytic solutions of Comparative Example 1 and Comparative Examples 8 to 10 in which no nitrile compound was added.
Further, the potential window of the electrolytic solution of Example 45 is 6.6 V (see FIG. 32), the potential window of the electrolytic solution of Example 46 is 5.4 V (see FIG. 33), and the potential window of the electrolytic solution of Example 47 is It became 6.1V (refer FIG. 34), and it turned out that all have spread to the positive side.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　同様に、リチウム塩をＬｉＰＦ６とした、他の実施例及び比較例の電解液について、電位－電流曲線から求めた、所定の電流密度となるときの電極電位を表２に示す。この表から、鎖式飽和炭化水素化合物の両末端にニトリル基が結合した鎖式飽和炭化水素ジニトリル化合物、鎖式エーテル化合物の末端の少なくとも一つにニトリル基が結合した鎖式エーテルニトリル化合物及びシアノ酢酸エステルのうち少なくとも一つのニトリル化合物と、環状カーボネート、環状エステル及び鎖状カーボネートのうち少なくとも一つとが含まれている場合に、正方向に電位窓が広がることが分かる。 Similarly, for the electrolytes of other examples and comparative examples in which the lithium salt is LiPF 6 , the electrode potential at a predetermined current density obtained from the potential-current curve is shown in Table 2. From this table, a chain saturated hydrocarbon dinitrile compound having a nitrile group bonded to both ends of the chain saturated hydrocarbon compound, a chain ether nitrile compound having a nitrile group bonded to at least one of the ends of the chain ether compound, and cyano It can be seen that the potential window widens in the positive direction when at least one nitrile compound of acetic acid ester and at least one of cyclic carbonate, cyclic ester and chain carbonate are contained.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
＜ニトリル添加量の影響＞
　本発明の電解液におけるニトリルの添加量の影響を調べるため、エチレンカーボネート：ジメチルカーボネート＝１：１(容量比)の混合溶媒に、所定量のセバコニトリルを添加し、電位電流曲線を測定した。なお、電解質はＬｉＰＦ６を１Ｍとなるように加えた（ただし、セバコニトリル１００容量％の場合には、１Ｍの溶解は困難であったため０．１Ｍとした）。結果を図３５に示す。この図から、セバコニトリルの添加量は、１容量％でも電位窓を広げる効果があり、添加量が増すほど電位窓は高電位方向に広がることが分かった。ただし、セバコニトリル１００容量％では、電解質であるＬｉＰＦ６の溶解度が低くなるとともに、粘度も高くなることから、伝導度が低くなり、ひいては電池の内部抵抗が高くなるという問題が生ずる。このため、リチウム電池用の電解液としては好ましいセバコニトリルの添加量は、１容量％以上１００容量％未満であり、より好ましくは５容量％以上９０容量％未満、最も好ましくは３０容量％以上７０容量％未満である。 <Influence of nitrile addition amount>
In order to examine the influence of the addition amount of nitrile in the electrolytic solution of the present invention, a predetermined amount of sebacononitrile was added to a mixed solvent of ethylene carbonate: dimethyl carbonate = 1: 1 (volume ratio), and a potential-current curve was measured. Incidentally, the electrolyte was added LiPF 6 as a 1M (However, in the case of sebaconitrile 100% by volume, it was 0.1M for dissolution of 1M was difficult). The results are shown in FIG. From this figure, it was found that the amount of sebacononitrile added had the effect of expanding the potential window even at 1% by volume, and the potential window expanded in the higher potential direction as the amount added increased. However, when 100% by volume of sebacononitrile is used, the solubility of LiPF 6 that is an electrolyte is lowered and the viscosity is also increased. Therefore, there is a problem that the conductivity is lowered and the internal resistance of the battery is increased. For this reason, the preferable amount of sebacononitrile added as an electrolyte for a lithium battery is 1% by volume or more and less than 100% by volume, more preferably 5% by volume or more and less than 90% by volume, and most preferably 30% by volume or more and 70% by volume. %.
　以上のように、実施例の電解液についての電位－電流曲線では、有機溶媒にニトリル化合物を加えることにより、電位窓が正の方向に大きく広がることが分かった。上記実施例の電位－電流曲線の測定においては、前述したように、正側及び負側に数回スキャンさせた後、自然電位から正方向、あるいは負方向に５ｍＶ／秒の速度で電位の掃引を行い、電位－電流曲線を測定している。この測定前の数回の電位のスキャンにおいては、2回以降において電位窓が広がっており、このことから、本発明の電解液中で正方向に電位掃引することにより、電位窓の広い電極を製造できることが分かる。 As described above, in the potential-current curve for the electrolyte solution of the example, it was found that the potential window greatly expanded in the positive direction by adding the nitrile compound to the organic solvent. In the measurement of the potential-current curve of the above example, as described above, after scanning several times on the positive side and the negative side, the potential is swept at a rate of 5 mV / sec from the natural potential in the positive direction or the negative direction. And the potential-current curve is measured. In the potential scan several times before this measurement, the potential window spreads after the second time. Therefore, by sweeping the potential in the positive direction in the electrolytic solution of the present invention, an electrode having a wide potential window is formed. It can be seen that it can be manufactured.
　以上より、下記の事項を開示する。
（１）　ニトリル化合物を含む有機溶媒中に電極を浸漬する浸漬工程と、
　前記浸漬工程後、前記電極を前記ニトリル化合物を含まない前記有機溶媒のみの液中に浸漬したときに印加可能な電位よりも高い電位を付与する正電圧付与工程と、を含むことを特徴とする電極の処理方法。
（２）　前記高い電位は（Ｌｉ／Ｌｉ+）参照電極に対して５．２Ｖを超える、好ましくは６．０Ｖ以上であることを特徴とする（１）の電極の処理方法。
（３）　前記ニトリル化合物は鎖式飽和炭化水素化合物の両末端にニトリル基が結合した鎖式飽和炭化水素ジニトリル化合物、鎖式エーテル化合物の末端の少なくとも一つにニトリル基が結合した鎖式エーテルニトリル化合物及びシアノ酢酸エステルのうち少なくとも一つであり、
　前記電極はカーボンからなる、ことを特徴とする（２）に記載の電極の処理方法。
（４）　鎖式飽和炭化水素化合物の両末端にニトリル基が結合した鎖式飽和炭化水素ジニトリル化合物、鎖式エーテル化合物の末端の少なくとも一つにニトリル基が結合した鎖式エーテルニトリル化合物及びシアノ酢酸エステルのうち少なくとも一つであるニトリル化合物を含む有機溶媒中に電極を浸漬する浸漬工程と、
　前記浸漬工程後、前記電極に正電圧を付与する正電圧付与工程と、を含むことを特徴とする電極の処理方法。 From the above, the following matters are disclosed.
(1) an immersion step of immersing the electrode in an organic solvent containing a nitrile compound;
And a positive voltage applying step for applying a potential higher than the potential that can be applied when the electrode is immersed in a liquid containing only the organic solvent that does not contain the nitrile compound after the immersion step. Electrode processing method.
(2) The method for treating an electrode according to (1), wherein the high potential is more than 5.2 V, preferably 6.0 V or more with respect to the (Li / Li + ) reference electrode.
(3) The nitrile compound is a chain saturated hydrocarbon dinitrile compound in which a nitrile group is bonded to both ends of a chain saturated hydrocarbon compound, or a chain ether nitrile in which a nitrile group is bonded to at least one end of a chain ether compound. At least one of a compound and a cyanoacetic acid ester,
The electrode processing method according to (2), wherein the electrode is made of carbon.
(4) A chain saturated hydrocarbon dinitrile compound having a nitrile group bonded to both ends of a chain saturated hydrocarbon compound, a chain ether nitrile compound having a nitrile group bonded to at least one terminal of the chain ether compound, and cyanoacetic acid An immersion step of immersing the electrode in an organic solvent containing a nitrile compound that is at least one of the esters;
And a positive voltage applying step of applying a positive voltage to the electrode after the immersion step.
＜電池特性の測定＞
　本発明のリチウムイオン電池用電解液の電池としての性能を評価するため、リチウム電池用陰極及びリチウム電池用正極を用いた電位－電流曲線を測定した。
　すなわち、上記実施例４１のリチウムイオン電池用電解液（すなわち、容量比でＥＣ：ＤＭＣ：セバコニトリル＝２５：２５：５０，リチウム塩としてＬｉＴＦＳＩ（リチウムビス（トリフルオロメタンスルホニル）イミド）を１．０ｍｏｌ／Ｌ）を用い、作用極にリチウム電池用陰極及びリチウム電池用陽極を用いて、リチウム吸蔵放出の電位－電流曲線を測定した。リチウム電池用陰極としてはＬｉ４Ｔｉ５Ｏ１２を用い、リチウム電池用正極としてはＬｉＣｏＯ２及びＬｉＣｏＰＯ４を用いた。測定にはポテンシオガルバノスタットを用いた。また、参照電極は（Ａｇ／Ａｇ+）を用いた。測定にあたっては、正側及び負側に数回スキャンさせた後、自然電位から正方向、あるいは負方向に０．５ｍＶ／秒の速度で電位の掃引を行い、電位－電流曲線を測定した。 <Measurement of battery characteristics>
In order to evaluate the performance of the electrolyte solution for lithium ion batteries of the present invention as a battery, a potential-current curve was measured using a lithium battery cathode and a lithium battery cathode.
That is, the electrolyte solution for lithium ion battery of Example 41 (that is, EC: DMC: sebacononitrile = 25: 25: 50 by volume ratio, LiTFSI (lithium bis (trifluoromethanesulfonyl) imide) as a lithium salt was 1.0 mol / L) was used, and a lithium battery cathode and a lithium battery anode were used as working electrodes, and a potential-current curve of lithium occlusion / release was measured. The cathode for a lithium battery using Li 4 Ti 5 O1 2, as a positive electrode for a lithium battery using LiCoO 2 and LiCoPO 4. A potentiogalvanostat was used for the measurement. Further, (Ag / Ag + ) was used as the reference electrode. In the measurement, after scanning several times on the positive side and the negative side, the potential was swept from the natural potential in the positive direction or the negative direction at a speed of 0.5 mV / sec, and the potential-current curve was measured.
　その結果、図３６に示すように、リチウム電池用陰極としてのＬｉ４Ｔｉ５Ｏ１２、リチウム電池用正極としてのＬｉＣｏＯ２及びＬｉＣｏＰＯ４のいずれの電極においても、リチウム（０）とリチウムイオンとの間での酸化還元に伴うほぼ可逆的な電流が観測された。この結果から、実施例４のリチウムイオン電池用電解液を用いることにより、リチウム（０）－リチウムイオン間の円滑な充放電が可能であることが分かった。 As a result, as shown in FIG. 36, Li 4 Ti 5 O 12 as the cathode for the lithium battery, LiCoO 2 and LiCoPO 4 as the cathode for the lithium battery, both of lithium (0) and lithium ions A nearly reversible current associated with redox was observed. From this result, it was found that by using the electrolyte for lithium ion battery of Example 4, smooth charge / discharge between lithium (0) and lithium ions was possible.
＜ナトリウムイオン電池の作製＞
　上記リチウムイオン電池に替えて、ナトリウムイオン電池用の正極、負極及び電解液を用いることにより、耐食性に極めて優れたナトリウムイオン電池とすることができる。 <Production of sodium ion battery>
By using a positive electrode, a negative electrode, and an electrolytic solution for a sodium ion battery instead of the lithium ion battery, a sodium ion battery having extremely excellent corrosion resistance can be obtained.
　この発明はリチウムイオン電池に適用される。
　ここに、リチウムイオン電池は電解液、正極、負極、セパレータ及びケースを備えてなる。 The present invention is applied to a lithium ion battery.
Here, the lithium ion battery includes an electrolytic solution, a positive electrode, a negative electrode, a separator, and a case.
（電解液）
　電解液はＬｉ塩（電解質）と有機溶媒とを含んでいる。
　Ｌｉ塩には、Ｌｉイオン電池用の一般的なＬｉ塩を用いることができる。例えば、ＬｉＰＦ6（六フッ化リン酸リチウム）、ＬｉＢＦ４（四フッ化ホウ酸リチウム）、ＬｉＴＦＳＩ（リチウムビス（トリフルオロメタンスルホニル）イミド）、ＬｉＴＦＳ（トリフルオロメタンスルホン酸リチウム）、ＬｉＢＥＴＩ（リチウムビス（ペンタフルオロエタンスルホニル）イミド）又はこれらの２種以上を用いることができる。
　なかでも、正極の酸化還元電位が４．５Ｖ以上のものについては、ＬｉＰＦ６、及び／又はＬｉＢＦ４を使用することが好ましい。また、ＬｉＴＦＳＩやＬｉＴＦＳやＬｉＢＥＴＩを用いる場合、ＬｉＰＦ６又はＬｉＢＦ４を添加することが好ましい。 (Electrolyte)
The electrolytic solution contains a Li salt (electrolyte) and an organic solvent.
As the Li salt, a general Li salt for a Li ion battery can be used. For example, LiPF 6 (lithium hexafluorophosphate), LiBF 4 (lithium tetrafluoroborate), LiTFSI (lithium bis (trifluoromethanesulfonyl) imide), LiTFS (lithium trifluoromethanesulfonate), LiBETI (lithium bis ( Pentafluoroethanesulfonyl) imide) or two or more thereof can be used.
Among them, for those redox potential of the positive electrode is more than 4.5V, it is preferable to use LiPF 6, and / or LiBF 4. In the case of using a LiTFSI and LiTFS and LiBETI, it is preferable to add LiPF 6 or LiBF 4.
　有機溶媒もＬｉイオン電池に用いられる一般的なものを採用できる。かかる有機溶媒としては環状炭酸エステル、環状カルボン酸エステル及び鎖状炭酸エステルの中から選ばれる１種、又は２種以上が好ましい。更に好ましくは、環状炭酸エステルと鎖状炭酸エステルとを併用する。具体的には、エチレンカーボネートとジメチルカーボネートとを併用することが特に好ましい。両者の配合割合は特に限定されない。環状カルボン酸エステルとしてはγ－ブチロラクトンを用いることができる。
　更にはニトリル化合物を有機溶媒として用いることができる。ここで、ニトリル化合物としては、鎖式飽和炭化水素化合物の両末端にニトリル基が結合した鎖式飽和炭化水素ジニトリル化合物、鎖式エーテル化合物の末端の少なくとも一つにニトリル基が結合した鎖式エーテルニトリル化合物及びシアノ酢酸エステルのうち少なくとも一つのニトリル化合物を挙げることができる。 As the organic solvent, a general solvent used for a Li ion battery can be adopted. Such an organic solvent is preferably one or more selected from cyclic carbonates, cyclic carboxylic acid esters and chain carbonates. More preferably, a cyclic carbonate and a chain carbonate are used in combination. Specifically, it is particularly preferable to use ethylene carbonate and dimethyl carbonate in combination. The blending ratio of both is not particularly limited. As the cyclic carboxylic acid ester, γ-butyrolactone can be used.
Furthermore, a nitrile compound can be used as an organic solvent. Here, as the nitrile compound, a chain saturated hydrocarbon dinitrile compound in which a nitrile group is bonded to both ends of a chain saturated hydrocarbon compound, a chain ether in which a nitrile group is bonded to at least one terminal of a chain ether compound. Mention may be made of at least one nitrile compound among nitrile compounds and cyanoacetic acid esters.
　鎖式飽和炭化水素化合物の両末端にニトリル基が結合した鎖式飽和炭化水素ジニトリル化合物としては、例えば、スクシノニトリルＮＣ（ＣＨ２）２ＣＮ、グルタロニトリルＮＣ（ＣＨ２）３ＣＮ、アジポニトリルＮＣ（ＣＨ２）４ＣＮ、セバコニトリルＮＣ（ＣＨ２）８ＣＮ、ドデカンジニトリルＮＣ（ＣＨ２）１０ＣＮなどのような直鎖状のジニトリル化合物の他、２－メチルグルタロニトリルＮＣＣＨ（ＣＨ３）ＣＨ２ＣＨ２ＣＮ等のように分枝を有していても良い。これらの鎖式飽和炭化水素ジニトリル化合物は、炭素数は特に限定されないが２０以下であることが好ましい。更に好ましくは７～１２である。 Examples of the chain saturated hydrocarbon dinitrile compound in which nitrile groups are bonded to both ends of the chain saturated hydrocarbon compound include succinonitrile NC (CH 2 ) 2 CN, glutaronitrile NC (CH 2 ) 3 CN, adiponitrile In addition to linear dinitrile compounds such as NC (CH 2 ) 4 CN, sebaconitrile NC (CH 2 ) 8 CN, dodecanedinitrile NC (CH 2 ) 10 CN, 2-methylglutaronitrile NCCH (CH 3 ) CH 2 CH 2 CN may have a branched as such. These chain saturated hydrocarbon dinitrile compounds are not particularly limited in carbon number, but are preferably 20 or less. More preferably, it is 7-12.
　鎖式エーテル化合物の末端の少なくとも一つにニトリル基が結合した鎖式エーテルニトリル化合物としては、オキシジプロピオニトリルＮＣＣＨ２ＣＨ２－Ｏ－ＣＨ２ＣＨ２ＣＮや、３－メトキシプロピオニトリルＣＨ３－Ｏ－ＣＨ２ＣＨ２ＣＮ等が挙げられる。これらの鎖式エーテルニトリル化合物は、炭素数は特に限定されないが、２０以下であることが好ましい。
　シアノ酢酸エステルとしてはシアノ酢酸メチル、シアノ酢酸エチル、シアノ酢酸プロピル、シアノ酢酸ブチル等が挙げられる。これらのシアノ酢酸エステルは、炭素数は特に限定されないが、２０以下であることが好ましい。 Examples of the chain ether nitrile compound in which a nitrile group is bonded to at least one end of the chain ether compound include oxydipropionitrile NCCH 2 CH 2 —O—CH 2 CH 2 CN and 3-methoxypropionitrile CH 3 -O-CH 2 CH 2 CN and the like can be mentioned. These chain ether nitrile compounds are not particularly limited in carbon number, but are preferably 20 or less.
Examples of cyanoacetic acid esters include methyl cyanoacetate, ethyl cyanoacetate, propyl cyanoacetate, and butyl cyanoacetate. These cyanoacetic acid esters are not particularly limited in carbon number, but are preferably 20 or less.
　これらニトリル化合物は電解液において電位窓を特に正方向に広げる作用を奏する。
　電位窓を広げる作用の観点からジニトリル化合物が好ましい。中でも、セバコニトリルの採用が更に好ましい。
　ただし、ニトリル化合物は粘度が高いので、上述の鎖状炭酸エステル、環状炭酸エステル及び／又は環状カルボン酸エステルと併用することが好ましい。更に好ましくはニトリル化合物と鎖状炭酸エステル及び環状炭酸エステルとを併用する。鎖状炭酸エステルとしてはジメチルカーボネートを採用することができ、環状炭酸エステルとしてはエチレンカーボネートを採用することができる。
　この場合、有機溶媒全体に占めるニトリル化合物の配合割合は１～９０容量％とすることが好ましい。更に好ましくは５～７０容量％であり、更に更に好ましくは、１０～５０容量％である。 These nitrile compounds have the effect of expanding the potential window particularly in the positive direction in the electrolytic solution.
A dinitrile compound is preferable from the viewpoint of the action of expanding the potential window. Of these, the use of sebacononitrile is more preferable.
However, since a nitrile compound has high viscosity, it is preferable to use together with the above-mentioned chain carbonate ester, cyclic carbonate ester, and / or cyclic carboxylic acid ester. More preferably, a nitrile compound, a chain carbonate ester and a cyclic carbonate ester are used in combination. Dimethyl carbonate can be employed as the chain carbonate, and ethylene carbonate can be employed as the cyclic carbonate.
In this case, the blending ratio of the nitrile compound in the whole organic solvent is preferably 1 to 90% by volume. More preferably, it is 5 to 70% by volume, and still more preferably 10 to 50% by volume.
Ｌｉ塩の濃度は０．０１mol／Ｌ以上であって、飽和状態よりも低い濃度とする。Ｌｉ塩の濃度が０．０１mol／Ｌ未満であると、Ｌｉイオンによるイオン伝導が小さくなり、電解液の電気抵抗が高くなるので好ましくない。他方、飽和状態を超えると、温度等の環境変化によって溶解しているＬｉ塩が析出するので好ましくない。 The concentration of the Li salt is 0.01 mol / L or more and is lower than the saturated state. When the concentration of the Li salt is less than 0.01 mol / L, ion conduction by Li ions is reduced, and the electric resistance of the electrolytic solution is increased, which is not preferable. On the other hand, exceeding the saturation state is not preferable because the dissolved Li salt precipitates due to environmental changes such as temperature.
（正極）
　正極は正極活物質と集電体とを備える。
（正極活物質）
　正極活物質とは「負極よりも高い電位で結晶構造内にリチウムが挿入／離脱され、それに伴って酸化／還元が行われる物質」をいう。
　正極活物質としては（１）酸化物系、（２）オリビン型結晶構造を有するリン酸塩系、及び（３）オリビンフッ化物系を挙げることができる。 (Positive electrode)
The positive electrode includes a positive electrode active material and a current collector.
(Positive electrode active material)
The positive electrode active material refers to “a material in which lithium is inserted / extracted in the crystal structure at a higher potential than the negative electrode, and oxidation / reduction is performed accordingly”.
Examples of the positive electrode active material include (1) an oxide system, (2) a phosphate system having an olivine type crystal structure, and (3) an olivine fluoride system.
（１）酸化物系
１－１具体的物質
　酸化物系としては、Ｌｉ１－ｘＣｏＯ２（ｘ＝０～１：層状構造）、Ｌｉ１－ｘＮｉＯ２（ｘ＝０～１：層状構造）、Ｌｉ１－ｘＭｎ２Ｏ４（ｘ＝０～１：スピネル構造）、Li2-yMnO3系（ｙ＝0～２）及びこれらの固溶体（ここで固溶体とは、上記酸化物系の正極活物質において金属原子が自由な割合で混合された物質を指す。）を挙げることができる。また、これらのうちの金属原子を他の金属原子でドープしたものも含まれる。ドーパントとしては酸化還元反応において電気化学的な特性を変化させられるものであれば特に限定されるものではない。例えば、Ｌi、Ｍｇ、Ａｌ、Ｔｉ、Ｖ、Ｍｎ、Ｆｅ、Ｃｏ、Ｎｉ、Ｃｕ、Ｚｎ、Ｚｒ、Ｎｂ及びＭｏの１種又はそれ以上を用いることができる。
１－２　特性
　この正極活物質の一般的な放電電位は５Ｖ　（ｖｓ　Ｌｉ／Ｌｉ＋）未満である。但し、ＬｉＭｎ２Ｏ４系でＮｉに一部置換した、ＬｉＮｉ０．５Ｍｎ１．５Ｏ４は、放電電位が４．７Ｖであり、急速充電をおこなう際には過電圧分を加味し、５Ｖを超える充電電圧を必要とする場合がある。また、ＬｉＣｏＭｎＯ４は放電電圧が５．２Ｖ程度から始まるため、これも充電電圧は５Ｖを超える。また、酸化物系は一般に３００℃未満で分解し、酸素発生とともに比較的大きな発熱反応がある。このため、過充電が起こらないような制御回路が必要とされる。 (1) Oxide-based 1-1 Specific Substances As oxide-based materials, Li 1-x CoO 2 (x = 0 to 1: layered structure), Li 1-x NiO 2 (x = 0 to 1: layered structure) ), Li 1-x Mn 2 O 4 (x = 0 to 1: spinel structure), Li 2-y MnO 3 system (y = 0 to 2) and solid solutions thereof (herein, the solid solution is the above oxide system) In which the metal atoms are mixed in a free ratio.). Moreover, what doped the metal atom of these with the other metal atom is also contained. The dopant is not particularly limited as long as the electrochemical characteristics can be changed in the oxidation-reduction reaction. For example, one or more of Li, Mg, Al, Ti, V, Mn, Fe, Co, Ni, Cu, Zn, Zr, Nb, and Mo can be used.
1-2 Characteristics A general discharge potential of this positive electrode active material is less than 5 V (vs Li / Li + ). However, LiNi 0.5 Mn 1.5 O 4 partially substituted with Ni in the LiMn 2 O 4 system has a discharge potential of 4.7 V, and takes into account overvoltage when performing rapid charging, and 5 V May require a charging voltage exceeding. Further, since LiCoMnO 4 starts with a discharge voltage of about 5.2V, the charge voltage also exceeds 5V. In addition, oxide systems generally decompose at less than 300 ° C., and have a relatively large exothermic reaction as oxygen is generated. Therefore, a control circuit that does not cause overcharging is required.
（２）オリビン型結晶構造を有するリン酸塩系
２－１具体的物質
　オリビン型結晶構造を有するリン酸塩系としては、Ｌｉ１－ｘＮｉＰＯ４　（ｘ＝０～１）、Ｌｉ１－ｘＣｏＰＯ４　（ｘ＝０～１）、Ｌｉ１－ｘＭｎＰＯ４　（ｘ＝０～１）、Ｌｉ１－ｘＦｅＰＯ４　（ｘ＝０～１）及びこれらの固溶体（ここで固溶体とは、上記リン酸塩系の正極活物質において金属原子が自由な割合で混合された物質を指す。）を挙げることができる。また、これらのうちの金属原子を他の金属原子でドープしたものも含まれる。ドーパントとしては酸化還元反応において電気化学的な特性を変化させられるものであれば特に限定されるものではない。例えば、Ｍｇ、Ａｌ、Ｔｉ、Ｖ、Ｍｎ、Ｆｅ、Ｃｏ、Ｎｉ、Ｃｕ、Ｚｎ、Ｚｒ、Ｎｂ及びＭｏの１種又は２種以上を用いることができる（特開２００８－１３０５２５号参照）。
２－２　特性
　この正極活物質の酸化還元電位は、上記酸化物系とは異なり３００℃未満では発熱反応が小さい上、酸素は発生せず、安全性が高いことから注目されている。また、リン酸塩系のうち、ＬｉＣｏＰＯ４系は放電電位が４．８Ｖ程度であり、急速充電に際しては５Ｖ以上で耐電圧を有する電解液が必要とされる。ＬｉＮｉＰＯ４の放電電位は５．２Ｖ　（ｖｓ　Ｌｉ／Ｌｉ＋）が示唆されている。 (2) Phosphate-based 2-1 specific substance having an olivine-type crystal structure Phosphate-based substances having an olivine-type crystal structure include Li 1-x NiPO 4 (x = 0 to 1), Li 1-x CoPO 4 (x = 0 to 1), Li 1-x MnPO 4 (x = 0 to 1), Li 1-x FePO 4 (x = 0 to 1) and their solid solutions (herein the solid solution is the above-mentioned phosphorus In the acid salt positive electrode active material, it refers to a material in which metal atoms are mixed in a free ratio. Moreover, what doped the metal atom of these with the other metal atom is also contained. The dopant is not particularly limited as long as the electrochemical characteristics can be changed in the oxidation-reduction reaction. For example, one or more of Mg, Al, Ti, V, Mn, Fe, Co, Ni, Cu, Zn, Zr, Nb, and Mo can be used (see JP 2008-130525 A).
2-2 Characteristics The oxidation-reduction potential of this positive electrode active material has been attracting attention because it has a low safety exothermic reaction at 300 ° C. and high safety because it does not generate oxygen. Of the phosphate systems, the LiCoPO 4 system has a discharge potential of about 4.8 V, and an electrolyte having a withstand voltage of 5 V or more is required for rapid charging. It is suggested that the discharge potential of LiNiPO 4 is 5.2 V (vs Li / Li + ).
（３）オリビンフッ化物系
３－１　具体的物質
　Ｌｉ２－ｘＮｉＰＯ４Ｆ　（ｘ＝０～２）、Ｌｉ２－ｘＣｏＰＯ４Ｆ　（ｘ＝０～２）が知られており、その他Ｌｉ２－ｘＭｎＰＯ４Ｆ　（ｘ＝０～２）、Ｌｉ２－ｘＦｅＰＯ４Ｆ　（ｘ＝０～２）が考えられる。
　また、これらの固溶体（ここで固溶体とは、上記オリビンフッ化物系の正極活物質において金属原子が自由な割合で混合された物質を指す。）も挙げることができる。さらに、これらのうちの金属原子を他の金属原子でドープしたものも含まれる。ドーパントとしては酸化還元反応において電気化学的な特性を変化させられるものであれば特に限定されるものではない。例えば、Ｍｇ、Ａｌ、Ｔｉ、Ｖ、Ｍｎ、Ｆｅ、Ｃｏ、Ｎｉ、Ｃｕ、Ｚｎ、Ｚｒ、Ｎｂ及びＭｏの１種又はそれ以上を用いることができる。
３－２　特性
　この正極活物質の酸化還元電位はオリビン系と同様に、上記酸化物系とは異なり、３００℃未満の分解では、発熱反応が小さい上、酸素発生がないため、正極活物質由来の電池発火の影響は小さいと考えられ安全性の面で注目されている。また、電池の電気容量密度（ｍＡｈ／ｇ）を上記リン酸塩系よりも高くできる（特開２００３－２２９１２６号公報参照）。しかし、例えばＬｉ２ＣｏＰＯ４Ｆ系は、平均放電電位が４．８Ｖ程度であり、急速充電に際しては５Ｖ以上で耐電圧を有する電解液が必要とされる。また、Ｌｉ２ＮｉＰＯ４Ｆ系の放電電位は５．２Ｖ（ｖｓ　Ｌｉ／Ｌｉ＋）程度であり、５Ｖ以上で耐電圧を有する電解液が必要とされる。 (3) Olivine fluoride system 3-1 Specific substances Li 2-x NiPO 4 F (x = 0-2), Li 2-x CoPO 4 F (x = 0-2) are known, and other Li 2 -x MnPO 4 F (x = 0 ~ 2), Li 2-x FePO 4 F (x = 0 ~ 2) is considered.
Further, these solid solutions (herein, the solid solution refers to a material in which metal atoms are mixed in a free ratio in the olivine fluoride-based positive electrode active material) can also be mentioned. Furthermore, the thing which doped the metal atom of these with another metal atom is also contained. The dopant is not particularly limited as long as the electrochemical characteristics can be changed in the oxidation-reduction reaction. For example, one or more of Mg, Al, Ti, V, Mn, Fe, Co, Ni, Cu, Zn, Zr, Nb, and Mo can be used.
3-2 Characteristics The oxidation-reduction potential of this positive electrode active material is different from that of the above-mentioned oxide type, as in the olivine type. Since decomposition is less than 300 ° C., the exothermic reaction is small and oxygen is not generated. The effect of battery ignition is considered to be small, and is attracting attention in terms of safety. Further, the electric capacity density (mAh / g) of the battery can be made higher than that of the phosphate system (see Japanese Patent Application Laid-Open No. 2003-229126). However, for example, the Li 2 CoPO 4 F system has an average discharge potential of about 4.8 V, and an electrolytic solution having a withstand voltage of 5 V or more is required for rapid charging. Further, the discharge potential of the Li 2 NiPO 4 F system is about 5.2 V (vs Li / Li + ), and an electrolytic solution having a withstand voltage at 5 V or more is required.
（４）その他
　その他、リチウム非含有のＦｅＦ３、有機導電性物質を用いた共役系ポリマー、シェブレル相化合物等を用いることもできる。また、遷移金属カルコゲン化物、バナジウム酸化物およびそのリチウム塩、ニオブ酸化物およびそのリチウム塩、さらには、複数の異なった正極活物質を混合して用いることも可能である。
　正極活物質粒子の平均粒径は、特に限定はされないが、１０ｎｍ～３０μｍであることが好ましい。 (4) Others In addition, lithium-free FeF 3 , a conjugated polymer using an organic conductive material, a chevrel phase compound, or the like can also be used. In addition, transition metal chalcogenides, vanadium oxides and lithium salts thereof, niobium oxides and lithium salts thereof, and a plurality of different positive electrode active materials may be used in combination.
The average particle diameter of the positive electrode active material particles is not particularly limited, but is preferably 10 nm to 30 μm.
（正極用集電体）
　正極用集電体とは正極活物質を担持する導電性の基板である。
　正極の集電体の成形材料は、充電時において安定であることが要求される。特に、酸化還元電位の高いオリビン型結晶構造を有するリン酸塩系及びオリビンフッ化物系の正極活物質を用いるときには、耐食性に優れた素材を使用することが好ましい。
　例えば、電解質としてＬｉＰＦ６、ＬｉＢＦ４を使用する場合、オーステナイト系ステンレス、Ｎｉ、Ａｌ、Ｔｉ等を用いることができるが、使用する正極活物質の動作電位を考慮し、適宜選択することが好ましい。例えば、電解質としてＬｉＰＦ６を用いる場合は、Ｌｉ／Ｌｉ+電極に対して６Ｖでも使用することができるが、電解質としてＬｉＢＦ４を用いる場合、ＳＵＳ３０４はＬｉ／Ｌｉ+電極に対し５．８Ｖ以下で充放電可能な場合のみ用いることができる。また、電解質としてＬｉＴＦＳＩを使用する場合、正極集電体表面に耐食性皮膜を形成させるべく、ＬｉＰＦ６を共存させることが好ましい。ＬｉＢＥＴＩ及びＬｉＴＦＳもＬｉＴＦＳＩの場合と同様である。
　また、Ａｌ等の導電金属材料へ導電性ＤＬＣ（ダイヤモンドライクカーボン）を周知の方法で被覆したものを集電体として用いることもできる。電解質がＬｉＢＦ４やＬｉＰＦ６など、容易にフッ化物皮膜を形成するようなリチウム塩の場合は、アルミニウム上へ厚いフッ化皮膜が形成し、耐食性は向上するものの、電子伝導性が低下し、ひいてはオーミック過電圧増加に伴う、高出力化が阻害されることとなる。Ａｌ等の導電金属材料へ導電性ＤＬＣを被覆すれば、フッ化物皮膜は導電性ＤＬＣの欠陥部分の極わずかな面積でのみ発生するだけである。このため、高電圧化しても電子伝導性の低下は無視できる程度となり、懸念されている高電圧化による出力低下は防ぐことが可能となる。
　ここで、導電性ダイヤモンドライクカーボンとは、ダイヤモンド結合（炭素同士のＳＰ３混成軌道結合）とグラファイト結合（炭素同士のＳＰ２混成軌道結合）の両方の結合が混在しているアモルファス構造をとるカーボンのうち、導電性が１０００Ωcm以下のものをいう。ただし、アモルファス構造以外に、部分的にグラファイト構造からなる結晶構造（すなわちＳＰ２混成軌道結合からなる六方晶系結晶構造）からなる相を有し、これにより導電性が発揮されるものも含まれる。グラファイトとダイヤモンドの中間の性質を有するダイヤモンドライクカーボンは、成膜時にダイヤモンドライクカーボンを構成する炭素原子のＳＰ２混成軌道結合とＳＰ３混成軌道結合の比率を調整することで、導電性を調節することができる。
　勿論、上記耐食性導電性金属材料を導電性ＤＬＣで被覆してもよい。
　集電体の形状及び構造は、正極活物質や電池の構造に応じて、任意に設計可能である。 (Current collector for positive electrode)
The positive electrode current collector is a conductive substrate carrying a positive electrode active material.
The molding material for the current collector of the positive electrode is required to be stable during charging. In particular, when using a phosphate-based and olivine fluoride-based positive electrode active material having an olivine-type crystal structure with a high redox potential, it is preferable to use a material excellent in corrosion resistance.
For example, when LiPF 6 or LiBF 4 is used as the electrolyte, austenitic stainless steel, Ni, Al, Ti, or the like can be used, but it is preferable to select them appropriately in consideration of the operating potential of the positive electrode active material to be used. For example, when LiPF 6 is used as the electrolyte, it can be used even at 6 V with respect to the Li / Li + electrode. However, when LiBF 4 is used as the electrolyte, SUS304 is 5.8 V or less with respect to the Li / Li + electrode. It can be used only when charge / discharge is possible. Further, when LiTFSI is used as the electrolyte, it is preferable that LiPF 6 coexists in order to form a corrosion-resistant film on the surface of the positive electrode current collector. LiBETI and LiTFS are the same as in LiTFSI.
In addition, a conductive metal material such as Al coated with conductive DLC (diamond-like carbon) by a well-known method can be used as a current collector. When the electrolyte is a lithium salt such as LiBF 4 or LiPF 6 that easily forms a fluoride film, a thick fluoride film is formed on the aluminum and the corrosion resistance is improved, but the electronic conductivity is lowered, and consequently The increase in output accompanying the increase in ohmic overvoltage is impeded. If the conductive metal material such as Al is coated with the conductive DLC, the fluoride film is generated only in a very small area of the defective portion of the conductive DLC. For this reason, even if the voltage is increased, the decrease in electron conductivity is negligible, and it is possible to prevent the decrease in output due to the increased voltage, which is a concern.
Here, the conductive diamond-like carbon is carbon having an amorphous structure in which both diamond bonds (SP 3 hybrid orbital bonds between carbons) and graphite bonds (SP 2 hybrid orbital bonds between carbons) are mixed. Among them, the one whose conductivity is 1000 Ωcm or less. However, in addition to the amorphous structure, those having a phase composed of a crystal structure partially composed of a graphite structure (that is, a hexagonal crystal structure composed of SP 2 hybrid orbital bonds) and thereby exhibiting conductivity are also included. . Diamond-like carbon having properties intermediate between graphite and diamond adjusts the conductivity by adjusting the ratio of SP 2 hybrid orbital bonds and SP 3 hybrid orbital bonds of the carbon atoms constituting diamond-like carbon during film formation. be able to.
Of course, you may coat | cover the said corrosion-resistant electroconductive metal material with electroconductive DLC.
The shape and structure of the current collector can be arbitrarily designed according to the structure of the positive electrode active material and the battery.
（正極の前処理）
　リチウムイオン電池用正極は、リチウムイオン電池に組み込む前に、ニトリル化合物を１容量％以上含む有機溶媒中にリチウム塩が溶解した前処理用電解液中に正電極を浸漬する浸漬処理工程を行い、さらに電極に正電圧を付与する正電圧処理工程を行なう。こうして前処理された電極は、ニトリル化合物を全く含まない電解液や、ニトリル化合物の添加量の少ない電解液を用いたリチウムイオン電池に用いても、電位窓が広く、高い電位においても電解液を分解し難くなる（特願２００９－１８０００７号参照）。このような広い電位窓の電極となる理由は、電極上に窒素を成分として含む耐食性の皮膜が形成されるためであると推測される。 (Pretreatment of positive electrode)
The positive electrode for a lithium ion battery performs an immersion treatment step of immersing the positive electrode in a pretreatment electrolytic solution in which a lithium salt is dissolved in an organic solvent containing 1% by volume or more of a nitrile compound before being incorporated in the lithium ion battery, Further, a positive voltage processing step for applying a positive voltage to the electrode is performed. The electrode thus pretreated has a wide potential window even when used in an electrolyte solution containing no nitrile compound or in a lithium ion battery using an electrolyte solution with a small amount of nitrile compound added. It becomes difficult to disassemble (see Japanese Patent Application No. 2009-180007). The reason why the electrode has such a wide potential window is presumed to be that a corrosion-resistant film containing nitrogen as a component is formed on the electrode.
（負極）
　負極は負極活物質と集電体とを備える。
（負極活物質）
　負極活物質とは「正極よりも低い電位で結晶構造内にリチウムが挿入／離脱され、それに伴って酸化／還元が行われる物質」をいう。
　負極活物質としては、例えば、人造黒鉛、天然黒鉛、ハードカーボン等の種々の炭素材料やチタン酸リチウム（Ｌｉ４Ｔｉ５Ｏ１２）、Ｈ２Ｔｉ１２Ｏ２５、Ｈ２Ｔｉ６Ｏ１３、Ｆｅ２Ｏ３などが挙げられる。また、これらを適宜混合した複合体も挙げることができる。さらには、Ｓｉ微粒子やＳｉ薄膜、これらのＳｉがＳｉ－Ｎｉ、Ｓｉ－Ｃｕ、Ｓｉ－Ｎｂ、Ｓｉ－Ｚｎ、Ｓｉ－Ｓｎ等のＳｉ系合金となった微粒子や薄膜が挙げられる。さらには、ＳｉＯ酸化物、Ｓｉ－ＳｉＯ２複合体、Ｓｉ－ＳｉＯ２－カーボンなどの複合体等を挙げることができる。 (Negative electrode)
The negative electrode includes a negative electrode active material and a current collector.
(Negative electrode active material)
The negative electrode active material refers to “a material in which lithium is inserted / extracted in the crystal structure at a lower potential than the positive electrode, and oxidation / reduction is performed accordingly”.
Examples of the negative electrode active material include various carbon materials such as artificial graphite, natural graphite, and hard carbon, lithium titanate (Li 4 Ti 5 O 12 ), H 2 Ti 12 O 25 , H 2 Ti 6 O 13 , Fe 2 O 3 etc. are mentioned. Moreover, the composite material which mixed these suitably can also be mentioned. Further, there are Si fine particles and Si thin films, and fine particles and thin films in which these Si are Si-based alloys such as Si—Ni, Si—Cu, Si—Nb, Si—Zn, and Si—Sn. Further, composites such as SiO oxide, Si—SiO 2 composite, Si—SiO 2 —carbon, and the like can be given.
（負極用集電体）
　負極用の集電体は汎用的な導電性金属材料、Ｃｕ、Ａｌ、Ｎｉ、Ｔｉ、オーステナイト系ステンレス等で形成することができる。
　但し、電解液にニトリル化合物を用いたとき（他の有機溶剤との併用を含む）には、電解液中のＬｉ塩に応じて適宜選択する必要がある。すなわち、電解質としてＬｉＰＦ６、ＬｉＢＦ４を使用する場合、オーステナイト系ステンレス、Ｎｉ、Ａｌ、Ｔｉ等の使用が可能となる。ただし、使用する負極活物質の動作電位に応じて、適宜選択する必要がある。負極活物質としてカーボン系やＳｉ系を使用する場合において、電解質としてＬｉＢＦ４を使用した場合は、Ｃｕ以外のＡｌ、Ｎｉ、Ｔｉ、オーステナイト系ステンレス等からなる集電体を使用することができる。負極活物質としてチタン酸リチウムやＦｅ２Ｏ３系の化合物を用いた場合は、Ｃｕを含む上記材料の全てが適用可能である。一方、電解質としてＬｉＰＦ６使用時はＡｌ、Ｎｉ及びＴｉが好ましく、オーステナイト系ステンレス及びＣｕは好ましくない。また、電解質としてＬｉＴＦＳＩや、ＬｉＢＥＴＩ、やＬｉＴＦＳを使用する場合、Ｎｉ、Ｔｉ、Ａｌ、Ｃｕ、オーステナイト系ステンレスの何れも使用することができる。 (Current collector for negative electrode)
The current collector for the negative electrode can be formed of a general-purpose conductive metal material, Cu, Al, Ni, Ti, austenitic stainless steel, or the like.
However, when a nitrile compound is used for the electrolytic solution (including combined use with other organic solvents), it is necessary to select appropriately according to the Li salt in the electrolytic solution. That is, when LiPF 6 or LiBF 4 is used as the electrolyte, austenitic stainless steel, Ni, Al, Ti, or the like can be used. However, it is necessary to select appropriately according to the operating potential of the negative electrode active material to be used. In the case of using carbon or Si as the negative electrode active material, when LiBF 4 is used as the electrolyte, a current collector made of Al, Ni, Ti, austenitic stainless or the like other than Cu can be used. In the case where lithium titanate or a Fe 2 O 3 based compound is used as the negative electrode active material, all of the above materials containing Cu are applicable. On the other hand, when LiPF 6 is used as the electrolyte, Al, Ni and Ti are preferable, and austenitic stainless steel and Cu are not preferable. In addition, when LiTFSI, LiBETI, or LiTFS is used as the electrolyte, any of Ni, Ti, Al, Cu, and austenitic stainless steel can be used.
（正極用電子伝導部材）
　正極活物質には導電性の小さいものがある。従って、正極活物質と集電体との間に導電性の電子伝導部材を介在させて、両者の間に十分な電子伝導パスを確保することが好ましい。正極用電子伝導部材として、電子伝導性を有する粉末状の導電助剤と呼ばれるものや、電子伝導性を有する板状のものがある。第１発明においては、導電性ダイヤモンドライクカーボン粉及びグラシーカーボン粉の少なくとも１種を用いるものであるが、それ以外の正極用電子伝導部材を併用することもできる。電子伝導部材は正極活物質と集電体との間に電子伝導パスを形成できればその形態は特に限定されるものではなく、導電性ダイヤモンドライクカーボン粉及びグラッシーカーボン粉の他、例えばアセチレンブラック等のカーボンブラック、グラファイト粉、等の導電性粉体（導電助剤）を用いることができる。ダイヤモンドライクカーボン及びグラッシーカーボンは、カーボンブラックやグラファイトよりもはるかに広い電位窓を有しており、高電位を付与した場合の耐食性に優れているため、好適に用いることができる。また、これらの導電助剤に金属微粒子が担持されていることも好ましい。金属微粒子としては、例えばＰｔ、Ａｕ、Ｎｉ等が挙げられる。これらは、単独で用いても良いし、これらの合金であっても良い。また、電子伝導材料として、正極活物質をダイヤモンドライクカーボンにより疎らに付着された導電性皮膜の他、正極活物質を埋入させた導電性薄板（金の薄板等）を用いることができる。 (Electroconductive member for positive electrode)
Some positive electrode active materials have low electrical conductivity. Therefore, it is preferable to provide a sufficient electron conduction path between the positive electrode active material and the current collector by interposing a conductive electron conduction member. As the electron conducting member for the positive electrode, there are a material called a powdery conductive additive having electron conductivity and a plate-like material having electron conductivity. In the first invention, at least one of conductive diamond-like carbon powder and glassy carbon powder is used, but other positive electrode electronic conductive members may be used in combination. The shape of the electron conducting member is not particularly limited as long as an electron conduction path can be formed between the positive electrode active material and the current collector. In addition to the conductive diamond-like carbon powder and the glassy carbon powder, for example, acetylene black, etc. Conductive powders (conductive aids) such as carbon black and graphite powder can be used. Diamond-like carbon and glassy carbon have a much wider potential window than carbon black and graphite, and are excellent in corrosion resistance when a high potential is applied, and therefore can be suitably used. Moreover, it is also preferable that metal fine particles are supported on these conductive assistants. Examples of the metal fine particles include Pt, Au, Ni and the like. These may be used alone or an alloy thereof. In addition to the conductive film in which the positive electrode active material is loosely attached by diamond-like carbon, a conductive thin plate (gold thin plate or the like) in which the positive electrode active material is embedded can be used as the electron conductive material.
（負極用電子伝導部材）
　正極用電子伝導部材と同様な物を用いることができる。 (Electroconductive member for negative electrode)
The thing similar to the electron conductive member for positive electrodes can be used.
（セパレータ）
　セパレータは電解液中へ浸漬され、正極と負極とを分離し両者の短絡を防ぐとともに、Ｌｉイオンの通過を許容する。
　かかるセパレータには、ポリエチレン、ポリプロピレン等のポリオレフィン系樹脂から成る多孔質フィルムが挙げられる。 (Separator)
The separator is immersed in the electrolytic solution, separates the positive electrode and the negative electrode, prevents a short circuit therebetween, and allows the passage of Li ions.
Examples of such separators include porous films made of polyolefin resins such as polyethylene and polypropylene.
（ケース）
　ケースは電解液に対する耐食性を有する材質で形成される。その形状は、電池の目的用途に応じて任意に設計できる。
　リチウム塩が溶解している電解液を使用する場合には、オーステナイト系ステンレスからなる基材、Ｔｉ、Ｎｉ及び／又はＡｌからなるケースを用いることができる。但し使用する正極、負極活物質の動作電位により適宜選択しなければならない場合もある。
　ケースが集電体を兼ねる場合や集電体に電気的に結合される場合は、各電極の集電体形成材料と同一若しくは同種の材料で形成される。 (Case)
The case is formed of a material having corrosion resistance against the electrolytic solution. The shape can be arbitrarily designed according to the intended use of the battery.
When using an electrolytic solution in which a lithium salt is dissolved, a base material made of austenitic stainless steel, a case made of Ti, Ni and / or Al can be used. However, there are cases where it is necessary to select appropriately depending on the operating potential of the positive electrode and negative electrode active material to be used.
When the case also serves as a current collector or is electrically coupled to the current collector, the case is formed of the same or the same material as the current collector forming material of each electrode.
　この発明は、上記発明の実施形態の説明に何ら限定されるものではない。特許請求の範囲の記載を逸脱せず、当業者が容易に想到できる範囲で種々の変形態様もこの発明に含まれる。 This invention is not limited to the description of the embodiment of the invention. Various modifications may be included in the present invention as long as those skilled in the art can easily conceive without departing from the description of the scope of claims.
　２ａ…正極活物質
　２ｂ…導電助剤（グラシーカーボン粉末）
　２…二次電池用正極
　３…負極
　１２ａ…正極活物質
　１２ｂ…ダイヤモンドライクカーボン
　１２ｃ…フッ素樹脂粉末
　１２…二次電池用正極
　１３…負極
　２１…集電体基材
　２２…耐食性皮膜
　２３…欠陥
　２４…不動態皮膜
　３９，４０…集電体 2a ... Positive electrode active material 2b ... Conductive aid (glassy carbon powder)
2 ... Positive electrode for secondary battery 3 ... Negative electrode 12a ... Positive electrode active material 12b ... Diamond-like carbon 12c ... Fluorine resin powder 12 ... Positive electrode for secondary battery 13 ... Negative electrode 21 ... Current collector base material 22 ... Corrosion-resistant film 23 ... Defect 24 ... Passive film 39, 40 ... Current collector

Claims (10)

  1. 　正極活物質と導電助剤とが含まれている二次電池用正極において、
    　前記導電助剤には導電性ダイヤモンドライクカーボン粉及びグラシーカーボン粉の少なくとも１種が含まれていることを特徴とする二次電池用正極。     In a positive electrode for a secondary battery containing a positive electrode active material and a conductive additive,
    The positive electrode for a secondary battery, wherein the conductive additive contains at least one of conductive diamond-like carbon powder and glassy carbon powder.
  2. 　前記正極活物質はＬｉ２ＮｉＰＯ４Ｆ、ＬｉＮｉＰＯ４、ＬｉＣｏＰＯ４及びＬｉ２ＣｏＰＯ４Ｆの少なくとも１種を含むことを特徴とする請求項１記載の二次電池用正極。 The positive active material is Li 2 NiPO 4 F, LiNiPO 4 , LiCoPO 4 and Li 2 CoPO 4 at least a positive electrode for a secondary battery according to claim 1, characterized in that it comprises one of F.
  3. 　請求項１又は２記載の二次電池用正極と、ニトリル化合物を含む電解液と、を備えていることを特徴とする二次電池。 A secondary battery comprising the positive electrode for a secondary battery according to claim 1 or 2 and an electrolytic solution containing a nitrile compound.
  4. 　正極活物質からなる粒子の集合体が所定の形状に成形された二次電池用正極において、
    　前記正極活物質からなる粒子には、乾式めっき法によって導電性ダイヤモンドライクカーボンが付着されていることを特徴とする二次電池用正極。     In a positive electrode for a secondary battery in which an aggregate of particles made of a positive electrode active material is formed into a predetermined shape,
    Conductive diamond-like carbon is attached to the particles made of the positive electrode active material by a dry plating method.
  5. 　前記正極活物質はＬｉ２ＮｉＰＯ４Ｆ、ＬｉＮｉＰＯ４、ＬｉＣｏＰＯ４及びＬｉ２ＣｏＰＯ４Ｆの少なくとも１種を含むことを特徴とする請求項４記載の二次電池用正極。 The positive active material is Li 2 NiPO 4 F, LiNiPO 4 , LiCoPO 4 and Li 2 CoPO 4 positive electrode for secondary battery according to claim 4, wherein the at least one F.
  6. 　請求項４又は５記載の二次電池用正極と、ニトリル化合物を含む電解液と、を備えていることを特徴とする二次電池。 A secondary battery comprising the positive electrode for a secondary battery according to claim 4 and an electrolyte containing a nitrile compound.
  7. 　アルミニウム、ニッケル若しくはチタンを主要構成成分とする集電体基材又はオーステナイト系ステンレスからなる集電体基材の表面に、導電性ダイヤモンドライクカーボン、グラッシーカーボン、金及び白金のうちの一種又は二種以上からなる導電性の耐食性皮膜が形成された集電体と、
    　有機溶媒と、を備えた電池であって、
    　前記有機溶媒には、鎖式飽和炭化水素化合物の両末端にニトリル基が結合した鎖式飽和炭化水素ジニトリル化合物、鎖式エーテル化合物の末端の少なくとも一つにニトリル基が結合した鎖式エーテルニトリル化合物及びシアノ酢酸エステルのうち少なくとも一つのニトリル化合物と、環状カーボネート、環状エステル及び鎖状カーボネートのうち少なくとも一つと、が含まれていることを特徴とする電池。     One or two of conductive diamond-like carbon, glassy carbon, gold and platinum on the surface of a current collector base material made of aluminum, nickel or titanium as a main constituent or a current collector base material made of austenitic stainless steel A current collector on which a conductive corrosion-resistant film comprising the above is formed;
    A battery comprising an organic solvent,
    The organic solvent includes a chain saturated hydrocarbon dinitrile compound in which a nitrile group is bonded to both ends of a chain saturated hydrocarbon compound, and a chain ether nitrile compound in which a nitrile group is bonded to at least one terminal of a chain ether compound. And at least one nitrile compound of cyanoacetate and at least one of cyclic carbonate, cyclic ester and chain carbonate.
  8. 　アルミニウム、ニッケル若しくはチタンを主要構成成分とする集電体基材又はオーステナイト系ステンレスからなる集電体基材の表面に、導電性ダイヤモンドライクカーボン、グラッシーカーボン、金及び白金のうちの一種又は二種以上からなる導電性の耐食性皮膜が形成された集電体であって、
    　前記該耐食性皮膜は欠陥が存在しており、該欠陥から露出する前記集電体基材の表面は、該集電体基材のフッ素化合物、酸素化合物、窒素化合物、炭素化合物、リン化合物、ホウ素化合物のうちの一種又は二種以上からなる不動態皮膜で覆われていることを特徴とする集電体。     One or two of conductive diamond-like carbon, glassy carbon, gold and platinum on the surface of a current collector base material made of aluminum, nickel or titanium as a main constituent or a current collector base material made of austenitic stainless steel A current collector formed with a conductive corrosion-resistant film comprising the above,
    The corrosion-resistant film has defects, and the surface of the current collector substrate exposed from the defects is a fluorine compound, oxygen compound, nitrogen compound, carbon compound, phosphorus compound, boron of the current collector substrate. A current collector covered with a passive film composed of one or more compounds.
  9. 　アルミニウム、ニッケル若しくはチタンを主要構成成分とする集電体基材又はオーステナイト系ステンレスからなる集電体基材の表面に、導電性ダイヤモンドライクカーボン、グラッシーカーボン、金及び白金のうちの一種又は二種以上からなる導電性の耐食性皮膜が形成された集電体と、
    　ＢＦ４アニオンとＰＦ６アニオンとの少なくとも一方を有する電解質を含む電解液と、を備えたことを特徴とする電池。     One or two of conductive diamond-like carbon, glassy carbon, gold and platinum on the surface of a current collector base material made of aluminum, nickel or titanium as a main constituent or a current collector base material made of austenitic stainless steel A current collector on which a conductive corrosion-resistant film comprising the above is formed;
    A battery comprising: an electrolyte solution containing an electrolyte having at least one of BF 4 anion and PF 6 anion.
  10. 　前記電解液は、鎖式飽和炭化水素化合物の両末端にニトリル基が結合した鎖式飽和炭化水素ジニトリル化合物、鎖式エーテル化合物の末端の少なくとも一つにニトリル基が結合した鎖式エーテルニトリル化合物及びシアノ酢酸エステルのうち少なくとも一つのニトリル化合物と、
    　環状カーボネート、環状エステル及び鎖状カーボネートのうち少なくとも一つと、
    　が含まれている有機溶媒を含むことを特徴とする請求項９記載の電池。     The electrolytic solution includes a chain saturated hydrocarbon dinitrile compound in which a nitrile group is bonded to both ends of the chain saturated hydrocarbon compound, a chain ether nitrile compound in which a nitrile group is bonded to at least one of the ends of the chain ether compound, and At least one nitrile compound of cyanoacetic acid ester;
    At least one of cyclic carbonate, cyclic ester and chain carbonate;
    The battery according to claim 9, further comprising an organic solvent containing
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