WO2014091799A1 - Electrode for nonaqueous electrolyte battery and nonaqueous electrolyte battery - Google Patents

Electrode for nonaqueous electrolyte battery and nonaqueous electrolyte battery Download PDF

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WO2014091799A1
WO2014091799A1 PCT/JP2013/072995 JP2013072995W WO2014091799A1 WO 2014091799 A1 WO2014091799 A1 WO 2014091799A1 JP 2013072995 W JP2013072995 W JP 2013072995W WO 2014091799 A1 WO2014091799 A1 WO 2014091799A1
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manganese oxide
electrode
oxide layer
manganese
electrolyte battery
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PCT/JP2013/072995
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French (fr)
Japanese (ja)
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俊輔 河野
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東洋鋼鈑株式会社
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    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G45/00—Compounds of manganese
    • C01G45/02—Oxides; Hydroxides
    • 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
    • H01M4/131—Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/139—Processes of manufacture
    • H01M4/1391—Processes of manufacture of electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/01—Particle morphology depicted by an image
    • C01P2004/03—Particle morphology depicted by an image obtained by SEM
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/10—Particle morphology extending in one dimension, e.g. needle-like
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/30—Particle morphology extending in three dimensions
    • C01P2004/45—Aggregated particles or particles with an intergrown morphology
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/54—Particles characterised by their aspect ratio, i.e. the ratio of sizes in the longest to the shortest dimension
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2006/00—Physical properties of inorganic compounds
    • C01P2006/40—Electric properties
    • 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
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/025—Electrodes composed of, or comprising, active material with shapes other than plane or cylindrical
    • 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
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/50—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese
    • H01M4/505—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
    • 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
    • H01M4/663—Selection of materials containing carbon or carbonaceous materials as conductive part, e.g. graphite, carbon fibres
    • 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
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present invention relates to a non-aqueous electrolyte battery electrode and a non-aqueous electrolyte battery obtained using the non-aqueous electrolyte battery electrode.
  • Non-aqueous electrolyte secondary batteries typified by lithium ion secondary batteries have a higher capacity than aqueous secondary batteries such as nickel-hydrogen batteries of the same volume or weight. It is used as a power source for mobile objects.
  • Patent Document 2 Although it is a technique using a positive electrode active material different from manganese dioxide, in Patent Document 2, for example, in the current method for producing a positive electrode by a coating method, the shape and size of the positive electrode active material to be applied are manufactured.
  • a technique is disclosed in which positive electrode active material particles are made into fine particles (nano) by controlling by the particle method, thereby improving the capacity per unit volume and unit weight by using the surface area improving effect by atomization.
  • the present invention has been made in view of such a situation, and an object thereof is to provide an electrode for a non-aqueous electrolyte battery capable of realizing a high discharge capacity, and a non-aqueous electrolyte battery including such an electrode. Objective.
  • the present inventors have conducted intensive studies, and in an electrode obtained by forming a manganese oxide layer by electrolytic treatment on a substrate, the microstructure of the manganese oxide layer and As a result of examining the relationship with the discharge capacity, it was found that an electrode capable of realizing a high discharge capacity can be obtained by making the manganese oxide layer have a specific fine structure, and the present invention is completed. It came to.
  • an electrode for use in a battery using a non-aqueous electrolyte which has a manganese oxide layer formed by electrolytic treatment on a substrate, and the manganese oxide layer is a surface.
  • an electrode for a non-aqueous electrolyte battery characterized by having a concavo-convex shape.
  • the manganese oxide layer is formed of secondary particles formed by agglomeration of manganese oxide particles, and includes a surface having a continuous uneven shape formed by the secondary particles. Is.
  • the manganese oxide layer has four or more convex portions formed of the secondary particles per 10 ⁇ m length.
  • the manganese oxide layer is formed of secondary particles formed by aggregation of acicular manganese oxide particles.
  • the aspect ratio of the acicular manganese oxide particles is 1: 3 to 1: 100.
  • the substrate is a substrate made of aluminum, an aluminum alloy, carbon, or carbon-coated aluminum.
  • the manganese oxide constituting the manganese oxide layer is manganese dioxide.
  • non-aqueous electrolyte battery comprising any one of the above-described non-aqueous electrolyte battery electrodes is provided.
  • an electrode for a non-aqueous electrolyte battery capable of realizing a high discharge capacity, and a non-aqueous electrolyte battery obtained using the electrode.
  • FIG. 1 is an SEM photograph of the surface of a manganese oxide layer for counting the number of convex portions.
  • FIG. 2 is an SEM photograph of the surface of the manganese oxide layer of Example 1.
  • FIG. 3 is a charge / discharge profile of Example 1.
  • 4 is a SEM photograph of the surface of the manganese oxide layer of Example 2.
  • FIG. 5 is a charge / discharge profile of Example 2.
  • 6 is a SEM photograph of the surface of the manganese oxide layer of Example 3.
  • FIG. 7 is a charge / discharge profile of Example 3.
  • FIG. 8 is a SEM photograph of the surface of the manganese oxide layer of Example 4.
  • FIG. 9 is a charge / discharge profile of Example 4.
  • FIG. 1 is an SEM photograph of the surface of a manganese oxide layer for counting the number of convex portions.
  • FIG. 2 is an SEM photograph of the surface of the manganese oxide layer of Example 1.
  • FIG. 3 is a charge / discharge profile of Example 1.
  • FIG. 10 is an SEM photograph of the surface of the manganese oxide layer of Example 5.
  • FIG. 11 is a charge / discharge profile of Example 5.
  • FIG. 12 is a SEM photograph of the surface of the manganese oxide layer of Comparative Example 1.
  • FIG. 13 is a charge / discharge profile of Comparative Example 1.
  • FIG. 14 is an SEM photograph of the surface of the manganese oxide layer of Comparative Example 2.
  • FIG. 15 is a charge / discharge profile of Comparative Example 2.
  • the electrode for a non-aqueous electrolyte battery of the present invention is an electrode used for a battery using a non-aqueous electrolyte, and has a manganese oxide layer formed by electrolytic treatment on a substrate, and the manganese The oxide layer has an uneven shape on the surface.
  • the substrate is not particularly limited, and any material can be used as long as it has conductivity.
  • the nonaqueous electrolyte battery electrode of the present invention is used as a positive electrode for a lithium ion battery.
  • aluminum, an aluminum alloy, or a carbon material it is preferable to use aluminum, an aluminum alloy, or a carbon material.
  • aluminum foil, aluminum alloy foil, or carbon fiber is preferably used as the base material from the viewpoint that the manganese oxide layer can be satisfactorily formed.
  • coating the coating material containing a carbon material on aluminum foil or aluminum alloy foil can also be used.
  • the manganese oxide layer is formed by performing electrolytic treatment on the above-described base material, and has a concavo-convex shape on the surface thereof.
  • the present invention is a method in which a manganese oxide layer is formed by electrolytic treatment and has a concavo-convex shape on the surface thereof.
  • the capacity can be increased.
  • manganese oxide to form a manganese oxide layer from the viewpoint that it is possible to increase the discharge capacity of manganese dioxide (MnO 2) is preferred.
  • the manganese oxide layer only needs to have a concavo-convex shape on its surface, but the manganese oxide layer aggregates manganese oxide particles from the viewpoint that the discharge capacity can be further increased. It is particularly preferable to be formed of secondary particles constituted by the above and having a continuous uneven shape formed of the secondary particles on the surface thereof.
  • the “state in which the surface of the manganese oxide layer has a continuous uneven shape formed by the secondary particles” means that the uneven shape resulting from the shape of the secondary particles is planar. In particular, in the surface, there is substantially no flat portion on the surface, and an uneven shape is continuously formed over the entire surface. It is preferable that a state is formed.
  • the manganese oxide layer is formed of secondary particles formed by agglomeration of manganese oxide particles, and continuous irregularities formed on the surface by the secondary particles.
  • the reaction area (specific surface area) of the manganese oxide particles can be efficiently increased, thereby further increasing the discharge capacity when used as an electrode for a non-aqueous electrolyte battery. Can be increased.
  • the secondary particles forming the manganese oxide layer may be formed by aggregation of manganese oxide particles as primary particles, and the manganese oxide particles as primary particles are aggregated.
  • the aggregated particles may be further aggregated. That is, the secondary particles may be formed by further aggregating aggregated particles obtained by agglomerating manganese oxide particles as primary particles.
  • the specific shape is not specifically limited, For example, per 10 micrometers in length Those having four or more convex portions formed of secondary particles are preferable.
  • it does not specifically limit as an upper limit of the number of the convex parts formed with the secondary particle per 10 micrometers in length Usually, it is 100 or less.
  • the method for measuring the number of convex portions per 10 ⁇ m in length is not particularly limited.
  • the manganese oxide layer was obtained by obtaining a cut surface in the thickness direction with a focused ion beam (FIB) apparatus. Concerning the cut surface, an SEM photograph was taken at a magnification of 10000 times, and two lines were drawn in parallel on the obtained SEM photograph at a magnification of 10000 times, and a convex portion located in and near the two lines It is possible to obtain the result by performing the operation of counting the number of points at five places and averaging the obtained results.
  • FIB focused ion beam
  • FIG. 1 is a SEM photograph (photo seen from an oblique direction) of the surface of the manganese oxide layer of Example 5 described later. In FIG. 1, two lines used for counting the convex portions are also shown. It also shows.
  • the shape of the manganese oxide particles constituting the manganese oxide layer is not particularly limited, but those having an acicular shape are preferred, and such acicular shaped manganese oxide particles are aggregated. It is more preferable to constitute secondary particles by doing so. That is, it is preferable that the acicular primary particles are aggregated to form particulate secondary particles.
  • the reaction area (specific surface area) of manganese oxide particles can be increased efficiently by making the manganese oxide particles constituting the manganese oxide layer have a needle-like shape. When used as an electrode for a non-aqueous electrolyte battery, the discharge capacity can be further increased.
  • the acicular manganese oxide particles are not particularly limited as long as they have an acicular shape, but the aspect ratio is a ratio of “minor axis: major axis”, preferably 1: 3 to 1: 100.
  • the ratio is preferably 1: 5 to 1:50, more preferably 1:10 to 1:50.
  • the method for measuring the aspect ratio of the acicular manganese oxide particles is not particularly limited.
  • the surface of the manganese oxide layer is obtained by taking a SEM photograph using a scanning electron microscope (SEM). In the obtained SEM photograph, by arbitrarily extracting 100 acicular manganese oxide particles, measuring the aspect ratio of 100 acicular manganese oxide particles, and averaging the obtained measurement results Can be sought.
  • the thickness of the manganese oxide layer is not particularly limited, but is preferably 0.5 to 40 ⁇ m, more preferably 1 to 25 ⁇ m. If the thickness of the manganese oxide layer is too thin, the total amount of manganese oxide may be too small and the total capacity may be reduced. On the other hand, if the thickness of the manganese oxide layer is too thick, the rate characteristics will decrease. There is a risk that.
  • the electrode for a non-aqueous electrolyte battery of the present invention can be obtained by subjecting a base material to an electrolytic treatment and forming a manganese oxide layer having the above-mentioned predetermined microstructure on the base material.
  • a manganese oxide layer having the above-described predetermined microstructure can be formed by performing electroplating on the substrate under the following conditions using a plating bath exemplified below. .
  • the manganese oxide for forming the manganese oxide layer is manganese dioxide (MnO 2 ) will be described as an example.
  • the plating bath may be a divalent Mn aqueous ions can be supplied Mn metal salt is not particularly limited, for example, manganese bath sulfate (MnSO 4), manganese chloride bath (MnCl 2), manganese nitrate bath (Mn (NO 3 ) 2 ), manganese acetate bath ((CH 3 COO) 2 Mn), or the like can be used.
  • Mn metal salt is not particularly limited, for example, manganese bath sulfate (MnSO 4), manganese chloride bath (MnCl 2), manganese nitrate bath (Mn (NO 3 ) 2 ), manganese acetate bath ((CH 3 COO) 2 Mn), or the like can be used.
  • Mn metal salt is not particularly limited, for example, manganese bath sulfate (MnSO 4), manganese chloride bath (MnCl 2), manganese nitrate bath (Mn (NO 3 ) 2 ), manganes
  • Manganese sulfate bath and manganese chloride bath have good workability and, in particular, the microstructure of the resulting manganese oxide layer can be controlled to a high degree, and the resulting non-aqueous electrolyte battery
  • the discharge capacity of the working electrode can be further increased.
  • a manganese sulfate bath and a manganese chloride bath it promotes acicularization of manganese oxide particles as primary particles contained in the obtained manganese oxide layer, and thereby, for the obtained non-aqueous electrolyte battery This is preferable because the discharge capacity of the electrode can be further increased, and particularly when a manganese chloride bath is used, this effect is remarkable, which is preferable.
  • the Mn ion concentration in the plating bath is preferably in the range of 0.05 to 3.0 mol / l, more preferably in the range of 0.1 to 0.7 mol / l. If the Mn ion concentration in the plating bath is less than 0.05 mol / l, plating deposition may become unstable. On the other hand, even if the Mn ion concentration in the plating bath exceeds 3.0 mol / l, there is no significant difference in the deposition behavior of the plating from the case where it is 3.0 mol / l or less. Therefore, it is preferably 3.0 mol / l or less.
  • the temperature of the plating bath is preferably 15 to 50 ° C., more preferably 20 to 40 ° C. If the temperature of the plating bath is less than 15 ° C., the deposition rate of the plating may be significantly reduced. On the other hand, if it exceeds 50 ° C., coarsening of particles occurs in the manganese oxide layer, The discharge capacity may be reduced.
  • cathodic electrolysis or anodic electrolysis may be used, and further, either constant current electrolysis or constant voltage electrolysis may be used, and constant current electrolysis or constant electrolysis with waveform (rectangular wave, triangular wave) control may be used.
  • waveform rectangular wave, triangular wave
  • voltage electrolysis may be used, anode constant current electrolysis is preferable from the viewpoint that the above-described manganese oxide layer having a predetermined fine structure can be satisfactorily formed.
  • the current density is preferably 0.01 to 4 A / dm 2 , more preferably 0.03 to 1 A / dm 2 .
  • the uneven structure of the manganese oxide layer can be made finer.
  • the current density is less than 0.01 A / dm 2 , long time plating is required. Then, the deposition of the plating becomes unstable, which is not preferable.
  • the current density is more than 4 A / dm 2 , the particles constituting the manganese oxide layer are enlarged, and the manganese oxide layer having the predetermined microstructure described above cannot be obtained. End up.
  • the manganese oxide layer having the predetermined fine structure described above can be formed.
  • acicularization of manganese oxide particles as primary particles contained in the obtained manganese oxide layer is promoted. This is preferable because the discharge capacity of the nonaqueous electrolyte battery electrode can be increased.
  • the nonaqueous electrolyte battery electrode of the present invention thus obtained can be suitably used as an electrode for a nonaqueous electrolyte battery such as a lithium ion secondary battery or a primary battery, particularly as a positive electrode. it can. That is, a lithium ion secondary battery will be described as an example.
  • An active material for example, metallic lithium or various carbon materials capable of doping and dedoping lithium with the nonaqueous electrolyte battery electrode of the present invention as a positive electrode.
  • Is laminated via a separator an electrode laminate is formed, the resulting electrode laminate is impregnated with a non-aqueous electrolyte, and sealed in a container as necessary, so that lithium An ion secondary battery can be obtained.
  • the non-aqueous electrolyte battery electrode of the present invention may be subjected to a pre-doping treatment in which lithium is doped in advance if necessary.
  • the nonaqueous electrolytic solution is not particularly limited, but an organic electrolytic solution in which a supporting electrolyte is dissolved in an organic solvent is used.
  • a supporting electrolyte for example, lithium salt is used as the lithium salt, LiPF 6, LiAsF 6, LiBF 4, LiSbF 6, LiAlCl 4, LiClO 4, CF 3 SO 3 Li, C 4 F 9 SO 3 Li, CF 3 COOLi, (CF 3 CO) 2 NLi, (CF 3 SO 2 ) 2 NLi, (C 2 F 5 SO 2 ) NLi, and the like can be given.
  • the organic solvent is not particularly limited as long as it can dissolve the supporting electrolyte, but dimethyl carbonate (DMC), ethylene carbonate (EC), diethyl carbonate (DEC), propylene carbonate (PC), butylene carbonate (BC), methyl Carbonates such as ethyl carbonate (MEC) and vinylene carbonate (VC); esters such as ⁇ -butyrolactone and methyl formate; ethers such as 1,2-dimethoxyethane (DME) and tetrahydrofuran; Sulfur compounds; and the like.
  • these organic solvents may be used independently and may be used in combination of 2 or more.
  • the manganese oxide layer as the active material layer that constitutes the electrode for the non-aqueous electrolyte battery is formed by electrolytic treatment. Therefore, the manganese oxide layer as the active material layer is substantially In particular, it can be made only of a manganese oxide as an active material, thereby increasing the unit weight and the discharge capacity per unit volume. That is, according to the present invention, when forming the manganese oxide layer as the active material layer, there is no need to blend a binder that does not contribute to battery capacity, conductive carbon, or the like. Since the discharge capacity is not reduced by adding conductive carbon, the discharge capacity per unit weight and unit volume can be increased as a result.
  • the adhesion at the interface between the base material and the manganese oxide layer can be increased.
  • the durability as an electrode can also be made excellent.
  • the manganese oxide layer is held on the substrate by the adhesive force of the binder.
  • the adhesion between the silicon oxide layer and the manganese oxide layer is not sufficient, and peeling tends to occur during long-term use.
  • such a problem can be effectively solved by forming the manganese oxide layer by electrolytic treatment.
  • the reaction area (specific surface area) of the manganese oxide as the active material is increased by making the surface of the manganese oxide layer as the active material layer have an uneven shape. Can do. And thereby, the reaction utilization factor of the manganese oxide contained in a manganese oxide layer can be raised, As a result, the discharge capacity per unit weight and unit volume can be raised.
  • a manganese oxide layer as an active material layer is formed by a coating method as in the prior art, there is a limit to the miniaturization of manganese oxide as an active material. There was a problem that the area could not be improved, and as a result, the discharge capacity was lowered. On the other hand, according to the present invention, such a problem can be effectively solved.
  • the discharge capacity per unit weight and unit volume can be increased. Therefore, when the discharge capacity of the same level as the conventional one is sufficient in the battery design, the thickness of the positive electrode is reduced. Therefore, the overall thickness of the battery can be reduced.
  • Example 1 Carbon fiber ("PyROFIL GDL", manufactured by Mitsubishi Rayon Co., Ltd., punched to a thickness of 0.2 mm, 14 mm ⁇ ) as a base material, 0.5 mol / l of a commercially available reagent-grade manganese (II) chloride tetrahydrate Using a plating bath obtained by dissolving in pure water, carbon fiber is used as an anode, and electroplating is performed by anode constant current electrolysis under the following conditions, whereby manganese dioxide is deposited on the surface of the carbon fiber. A positive electrode was obtained by forming a layer made of (MnO 2 ).
  • the obtained layer made of manganese dioxide weighed 1.8 mg and was equivalent to 2.32 ⁇ m by a gravimetric method.
  • Plating bath 0.5M manganese chloride aqueous solution (bath temperature: 40 ° C., pH: 3.0)
  • Current application method anode constant current electrolysis anode current density: 0.05 A / dm 2
  • Anode energization amount 40 C (/ 16 cm 2 )
  • Cathode Platinum plate
  • the film thickness of the layer made of manganese dioxide is obtained by determining the weight of the layer made of manganese dioxide from the weight change before and after electroplating, and the obtained weight, the surface area of the base material, and the density of manganese dioxide From (5.03 g / cm 3 ), the weight was calculated.
  • FIG. 2 (A) and FIG. 2 (B) The SEM photograph of the surface of the layer which consists of manganese dioxide is shown to FIG. 2 (A) and FIG. 2 (B).
  • FIG. 2B which is a 20,000-fold photograph, the obtained manganese dioxide layer is formed of secondary particles formed by agglomeration of acicular manganese oxide particles. It was confirmed that In this example, the 5000 times SEM photograph shown in FIG. 2A is the observation voltage (acceleration voltage) 15 kV, and the 20,000 times SEM photograph shown in FIG.
  • the number of convex portions per 10 ⁇ m length and the aspect ratio of acicular manganese oxide particles were measured. The results are shown in Table 1.
  • the number of convex parts per 10 ⁇ m in length was obtained by taking a 10,000 times SEM photograph in the main body of the scanning electron microscope for the obtained layer of manganese dioxide, and obtaining a 10,000 times SEM photograph. With respect to the SEM photograph, two lines are drawn in parallel on the SEM photograph, and the operation of counting the number of convex portions located in the two lines and in the vicinity of the two lines is performed at five points, and the obtained results are averaged.
  • the aspect ratio of the acicular manganese oxide particles is obtained by extracting 100 arbitrary acicular manganese oxide particles using the SEM photograph of the surface of the layer made of manganese dioxide, and measuring the aspect ratio. The obtained results were obtained by averaging.
  • the positive electrode obtained above and metallic lithium (15 mm ⁇ , thickness 0.3 mm) as a negative electrode are laminated via a separator (“Celguard # 2400”, manufactured by Celgard, 18 mm ⁇ , thickness 0.025 mm). And it accommodated in the coin battery case made from SUS316L, and after adding electrolyte solution, it sealed, and produced the 2032 type coin electric field (diameter 20mm x height 3.2mm).
  • Example 2 Carbon fiber ("PyROFIL GDL", manufactured by Mitsubishi Rayon Co., Ltd., punched to a thickness of 0.2 mm, 14 mm ⁇ ) as a base material, 0.5 mol / l of a commercially available reagent-grade manganese (II) chloride tetrahydrate Using a plating bath obtained by dissolving in pure water, carbon fiber is used as an anode, and electroplating is performed by anode constant current electrolysis under the following conditions, whereby manganese dioxide is deposited on the surface of the carbon fiber. A positive electrode was obtained by forming a layer made of (MnO 2 ).
  • the layer which consists of obtained manganese dioxide was 4.2 mg in weight, and was equivalent to 5.42 micrometers by the film thickness by a gravimetric method.
  • Plating bath 0.5M manganese chloride aqueous solution (bath temperature: 40 ° C., pH: 3.0)
  • Current application method anode constant current electrolysis anode current density: 0.05 A / dm 2
  • Anode energization amount 104 C (/ 16 cm 2 )
  • Cathode Platinum plate
  • FIG. 5 shows the charge / discharge profile obtained as a result of the charge / discharge test
  • Table 1 shows the average discharge capacity in the 5-cycle charge / discharge test.
  • Example 3 Carbon fiber (“PyROFIL GDL”, manufactured by Mitsubishi Rayon Co., Ltd., punched to a thickness of 0.2 mm, 14 mm ⁇ ) as a base material, 0.5 mol / l of a commercially available reagent-grade manganese (II) sulfate pentahydrate Using a plating bath obtained by dissolving in pure water, carbon fiber is used as an anode, and electroplating is performed by anode constant current electrolysis under the following conditions, whereby manganese dioxide is deposited on the surface of the carbon fiber. A positive electrode was obtained by forming a layer made of (MnO 2 ).
  • the layer which consists of obtained manganese dioxide was 1.7 mg in weight, and was equivalent to 2.20 micrometers in the film thickness by a gravimetric method.
  • Plating bath 0.5M manganese sulfate aqueous solution (bath temperature: 40 ° C., pH: 3.0)
  • Current application method anode constant current electrolysis anode current density: 0.01 A / dm 2
  • Anode energization amount 29 C (/ 16 cm 2 )
  • Cathode Platinum plate
  • FIG. 7 shows the charge / discharge profile obtained as a result of the charge / discharge test
  • Table 1 shows the average discharge capacity in the 5-cycle charge / discharge test.
  • Example 4 Carbon fiber (“PyROFIL GDL”, manufactured by Mitsubishi Rayon Co., Ltd., punched to a thickness of 0.2 mm, 14 mm ⁇ ) as a base material, 0.5 mol / l of a commercially available reagent-grade manganese (II) sulfate pentahydrate Using the plating bath obtained by dissolving in pure water, using carbon fiber as an anode and performing electroplating by constant voltage electrolysis under waveform control under the following conditions, the surface of carbon fiber is A positive electrode was obtained by forming a layer made of manganese dioxide (MnO 2 ). The obtained layer of manganese dioxide weighed 1.0 mg and was equivalent to 1.29 ⁇ m in weight by gravimetric method.
  • MnO 2 manganese dioxide
  • Plating bath 0.5M manganese sulfate aqueous solution (bath temperature: 40 ° C., pH: 3.0)
  • Current application method Waveform control Anode energization amount: 29 C (/ 16 cm 2 )
  • Cathode Platinum plate
  • constant voltage electrolysis by waveform control was performed by cell voltage control by a potential sweep method under the following conditions. 1st cell voltage: immersion potential ⁇ 1.8 V (sweep speed 440 mV / s) 2nd cell voltage: 1.8 V ⁇ 2.5 V (sweep speed 29 mV / s) 3rd cell voltage: 2.5 V ⁇ 2.7 V (sweep speed 0.1 mV / s)
  • FIGS. 8 (A) and 8 (B) are shown in FIGS. 8 (A) and 8 (B).
  • FIG. 8 (B) which is a 20,000 times photograph, one formed by secondary particles constituted by aggregation of acicular manganese oxide particles (specifically, acicular It was confirmed that the agglomerated particles formed by agglomeration of the manganese oxide particles were formed by secondary particles formed by further agglomeration).
  • the number of convex portions per 10 ⁇ m length and the aspect ratio of acicular manganese oxide particles were measured in the same manner as in Example 1. The results are shown in Table 1.
  • FIG. 9 shows the charge / discharge profile obtained as a result of the charge / discharge test, and Table 1 shows the average discharge capacity in the 5-cycle charge / discharge test.
  • Example 5 Dissolve commercially available reagent-grade manganese (II) sulfate pentahydrate in pure water at 0.5 mol / l in an aluminum alloy foil (A3104, 200 ⁇ m thick, punched to 14 mm ⁇ ) as a base material as a base material
  • a layer made of manganese dioxide (MnO 2 ) is formed on the surface of the carbon fiber by performing electroplating by anode constant current electrolysis under the following conditions using the aluminum alloy foil as an anode using the plating bath obtained by By forming, a positive electrode was obtained.
  • the obtained manganese dioxide layer weighed 0.2 mg, and the film thickness measured on the cut surface in the thickness direction by the FIB apparatus was 1.5 ⁇ m.
  • Plating bath 0.5M manganese sulfate aqueous solution (bath temperature: 40 ° C., pH: 3.0)
  • Current application method anode constant current electrolysis anode current density: 0.05 A / dm 2
  • Anode energization amount 57.6 C (/ 16 cm 2 )
  • Cathode Platinum plate
  • FIG. 11 shows the charge / discharge profile obtained as a result of the charge / discharge test
  • Table 1 shows the average discharge capacity in the 5-cycle charge / discharge test.
  • Comparative Example 1 Carbon fiber (“PyROFIL GDL”, manufactured by Mitsubishi Rayon Co., Ltd., punched to a thickness of 0.2 mm, 14 mm ⁇ ) as a base material, 0.5 mol / l of a commercially available reagent-grade manganese (II) sulfate pentahydrate Using a plating bath obtained by dissolving in pure water, carbon fiber is used as an anode, and electroplating is performed by anode constant current electrolysis under the following conditions, whereby manganese dioxide is deposited on the surface of the carbon fiber. A positive electrode was obtained by forming a layer made of (MnO 2 ).
  • the obtained layer made of manganese dioxide weighed 1.8 mg and was equivalent to 2.32 ⁇ m by a gravimetric method.
  • Plating bath 0.5M manganese sulfate aqueous solution (bath temperature: 40 ° C., pH: 3.0)
  • Current application method Anode constant current electrolysis
  • Anode current density 5.0 A / dm 2
  • Anode energization amount 29 C (/ 16 cm 2 )
  • Cathode Platinum plate
  • FIG. 13 shows the charge / discharge profile obtained as a result of the charge / discharge test
  • Table 1 shows the average discharge capacity in the 5-cycle charge / discharge test.
  • Comparative Example 2 Pure water such that a commercially available reagent-grade manganese (II) chloride tetrahydrate is 0.5 mol / l on a Ni-plated aluminum plate (Ni plating thickness 1.0 ⁇ m, substrate thickness 0.3 mm) as a substrate.
  • a plating bath obtained by dissolving in a nickel plating aluminum plate as an anode, and electroplating by anode constant current electrolysis under the following conditions, manganese dioxide ( A layer made of MnO 2 ) was formed.
  • Plating bath 0.5M manganese sulfate aqueous solution (bath temperature: 40 ° C., pH: 3.0)
  • Current application method anode constant current electrolysis anode current density: 0.05 A / dm 2
  • Anode energization amount 230 C (/ 16 cm 2 )
  • Cathode Platinum plate
  • the layer made of manganese dioxide is peeled off from the Ni-plated aluminum plate on which the layer made of manganese dioxide is formed, and the peeled layer made of manganese dioxide is made into a particle diameter of several ⁇ m to several tens ⁇ m using a mortar.
  • the process which crushes was performed, and then the manganese dioxide after the crushing was filtered and then dried to obtain a manganese dioxide powder.
  • 9 mg of ketjen black as a conductive additive and 7 mg of polyvinylidene fluoride as a binder were added, and then 800 mg of N-methylpyrrolidone was added to adjust the viscosity to be applicable, thereby adding a positive electrode slurry.
  • FIG. 15 shows the charge / discharge profile obtained as a result of the charge / discharge test
  • Table 1 shows the average discharge capacity in the 5-cycle charge / discharge test.
  • the discharge capacity indicates the capacity per unit weight of the electrode active material layer as “mAh / g”.
  • the discharge capacity with respect to the weight including the weight of ketjen black as a conductive auxiliary agent and polyvinylidene fluoride as a binder which does not contribute.
  • “5 cycles of average discharge capacity” indicates discharge capacity per weight of a layer made of manganese dioxide as an active material layer (that is, discharge capacity per active material layer).
  • “base material” indicates a base material of an electrode in measuring the average discharge capacity of 5 cycles, and in Comparative Example 2, from manganese dioxide formed on another base material by a coating method. Since the average discharge capacity of 5 cycles was measured using a layer formed by peeling and pulverizing and forming this on carbon fiber, the “substrate” is made of carbon fiber.

Abstract

Provided is an electrode for a nonaqueous electrolyte battery that is used in a battery that uses a nonaqueous electrolyte, and is characterized by having a manganese oxide layer formed on a substrate by electrolytic treatment, and by the manganese oxide layer having recesses and projections on the surface. In the present invention, the manganese oxide layer is formed by secondary particles constituted by the aggregation of manganese oxide particles, and is preferably provided with a surface having continuous recesses and projections formed by the secondary particles.

Description

非水電解液電池用電極および非水電解液電池Nonaqueous electrolyte battery electrode and nonaqueous electrolyte battery
　本発明は、非水電解液電池用電極、および該非水電解液電池用電極を用いて得られる非水電解液電池に関する。 The present invention relates to a non-aqueous electrolyte battery electrode and a non-aqueous electrolyte battery obtained using the non-aqueous electrolyte battery electrode.
　リチウムイオン二次電池に代表される非水電解液二次電池は、同体積あるいは同重量のニッケル水素電池等の水系二次電池に比べ高容量であることから、各種モバイル機器や電気自動車等の移動体向けの電源として用いられている。 Non-aqueous electrolyte secondary batteries typified by lithium ion secondary batteries have a higher capacity than aqueous secondary batteries such as nickel-hydrogen batteries of the same volume or weight. It is used as a power source for mobile objects.
　一方で、このような非水電解液二次電池の特性の向上に対する要求（たとえば、重量当たりあるいは体積当たりの容量や出力の向上に対する要求）、とりわけ電気自動車等の移動体用途における要求は年々高まっており、特に、このような移動体用途においては、軽量小型化を実現しながら、高容量および高出力を達成することが求められている。このような要求に応えるための試みとして、たとえば、非水電解液二次電池を構成する正極および負極の単位体積および単位重量当たりの容量を向上させる試みや、正極活物質や負極活物質として新たな材料を用いる試みなどがなされている。 On the other hand, demands for improving the characteristics of such non-aqueous electrolyte secondary batteries (for example, demands for improvement in capacity and output per weight or volume), especially in mobile applications such as electric vehicles, are increasing year by year. In particular, in such mobile applications, it is required to achieve high capacity and high output while realizing light weight and downsizing. As an attempt to meet such a demand, for example, an attempt to improve the capacity per unit volume and unit weight of the positive electrode and the negative electrode constituting the nonaqueous electrolyte secondary battery, a new positive electrode active material and a negative electrode active material, Attempts have been made to use new materials.
　このような状況において、従来より一次電池の正極活物質として用いられている電解二酸化マンガン（ＭｎＯ２）を、リチウムイオン二次電池用の正極活物質として用いることが検討されている（たとえば、特許文献１参照）。しかしながら、二酸化マンガンは、リチウムイオン二次電池用の正極活物質として一般的に用いられているコバルト酸リチウムと比較して、その理論容量は高いものの、実用上は容量が極めて低いものであり、そのため実用化に至っていないのが現状である。 Under such circumstances, the use of electrolytic manganese dioxide (MnO 2 ), which has been conventionally used as a positive electrode active material for primary batteries, as a positive electrode active material for lithium ion secondary batteries has been studied (for example, patents). Reference 1). However, compared with lithium cobaltate generally used as a positive electrode active material for lithium ion secondary batteries, manganese dioxide has a high theoretical capacity, but has a very low capacity in practical use. For this reason, it has not yet been put into practical use.
　これに対し、二酸化マンガンとは異なる正極活物質を用いた技術ではあるが、たとえば、特許文献２では、現行の塗布法による正極の製造方法において、塗布する正極活物質の形状および大きさを造粒法により制御することで、正極活物質粒子を微粒（ナノ）化し、これにより、微粒化による表面積向上効果を用いて単位体積および単位重量当たりの容量を向上させる技術が開示されている。 On the other hand, although it is a technique using a positive electrode active material different from manganese dioxide, in Patent Document 2, for example, in the current method for producing a positive electrode by a coating method, the shape and size of the positive electrode active material to be applied are manufactured. A technique is disclosed in which positive electrode active material particles are made into fine particles (nano) by controlling by the particle method, thereby improving the capacity per unit volume and unit weight by using the surface area improving effect by atomization.
特開平１１－８６９０４号公報Japanese Patent Laid-Open No. 11-86904 特開２００３－２７２６２９号公報JP 2003-272629 A
　しかしながら、上述した特許文献２に記載された技術のように、二酸化マンガンを微粒化し、塗布法により正極を形成した場合でも、得られた二酸化マンガン正極において得られる容量は十分でなく、そのため、実用化に至るものではなかった。 However, even when the manganese dioxide is atomized and the positive electrode is formed by a coating method as in the technique described in Patent Document 2 described above, the capacity obtained in the obtained manganese dioxide positive electrode is not sufficient, so that It did not lead to the transformation.
　本発明は、このような実状に鑑みてなされ、その目的は、高放電容量が実現可能な非水電解液電池用の電極、およびこのような電極を備える非水電解液電池を提供することを目的とする。 The present invention has been made in view of such a situation, and an object thereof is to provide an electrode for a non-aqueous electrolyte battery capable of realizing a high discharge capacity, and a non-aqueous electrolyte battery including such an electrode. Objective.
　本発明者等は、上記課題を解決するために、鋭意検討を行ったところ、基材上に、電解処理によりマンガン酸化物層を形成して得られる電極において、マンガン酸化物層の微細構造と放電容量との関係について検討を行ったところ、マンガン酸化物層を特定の微細構造を有するものとすることにより、高放電容量が実現可能な電極を得ることができることを見出し、本発明を完成させるに至った。 In order to solve the above-mentioned problems, the present inventors have conducted intensive studies, and in an electrode obtained by forming a manganese oxide layer by electrolytic treatment on a substrate, the microstructure of the manganese oxide layer and As a result of examining the relationship with the discharge capacity, it was found that an electrode capable of realizing a high discharge capacity can be obtained by making the manganese oxide layer have a specific fine structure, and the present invention is completed. It came to.
　すなわち、本発明によれば、非水電解液を用いた電池に用いる電極であって、基材の上に、電解処理により形成されたマンガン酸化物層を有し、前記マンガン酸化物層が表面に凹凸形状を有することを特徴とする非水電解液電池用電極が提供される。 That is, according to the present invention, there is provided an electrode for use in a battery using a non-aqueous electrolyte, which has a manganese oxide layer formed by electrolytic treatment on a substrate, and the manganese oxide layer is a surface. There is provided an electrode for a non-aqueous electrolyte battery characterized by having a concavo-convex shape.
　好ましくは、前記マンガン酸化物層が、マンガン酸化物粒子が凝集することにより構成された二次粒子で形成されており、かつ、前記二次粒子によって形成された連続した凹凸形状を有する表面を備えるものである。
　好ましくは、前記マンガン酸化物層は、長さ１０μｍあたりに、前記二次粒子により形成された凸部を４個以上有する。
　好ましくは、前記マンガン酸化物層が、針状のマンガン酸化物粒子が凝集することにより構成された二次粒子で形成されている。
　好ましくは、前記針状のマンガン酸化物粒子のアスペクト比が、１：３～１：１００である。
　好ましくは、前記基材が、アルミニウム、アルミニウム合金、炭素または炭素被覆アルミニウムからなる基材である。
　好ましくは、前記マンガン酸化物層を構成するマンガン酸化物が、二酸化マンガンである。 Preferably, the manganese oxide layer is formed of secondary particles formed by agglomeration of manganese oxide particles, and includes a surface having a continuous uneven shape formed by the secondary particles. Is.
Preferably, the manganese oxide layer has four or more convex portions formed of the secondary particles per 10 μm length.
Preferably, the manganese oxide layer is formed of secondary particles formed by aggregation of acicular manganese oxide particles.
Preferably, the aspect ratio of the acicular manganese oxide particles is 1: 3 to 1: 100.
Preferably, the substrate is a substrate made of aluminum, an aluminum alloy, carbon, or carbon-coated aluminum.
Preferably, the manganese oxide constituting the manganese oxide layer is manganese dioxide.
　また、本発明によれば、上記いずれかに記載の非水電解液電池用電極を備える非水電解液電池が提供される。 Moreover, according to the present invention, a non-aqueous electrolyte battery comprising any one of the above-described non-aqueous electrolyte battery electrodes is provided.
　本発明によれば、高放電容量が実現可能な非水電解液電池用の電極、および該電極を用いて得られる非水電解液電池を提供することができる。 According to the present invention, it is possible to provide an electrode for a non-aqueous electrolyte battery capable of realizing a high discharge capacity, and a non-aqueous electrolyte battery obtained using the electrode.
図１は、凸部の数のカウント用のマンガン酸化物層の表面のＳＥＭ写真である。FIG. 1 is an SEM photograph of the surface of a manganese oxide layer for counting the number of convex portions. 図２は、実施例１のマンガン酸化物層表面のＳＥＭ写真である。FIG. 2 is an SEM photograph of the surface of the manganese oxide layer of Example 1. 図３は、実施例１の充放電プロファイルである。FIG. 3 is a charge / discharge profile of Example 1. 図４は、実施例２のマンガン酸化物層表面のＳＥＭ写真である。4 is a SEM photograph of the surface of the manganese oxide layer of Example 2. FIG. 図５は、実施例２の充放電プロファイルである。FIG. 5 is a charge / discharge profile of Example 2. 図６は、実施例３のマンガン酸化物層表面のＳＥＭ写真である。6 is a SEM photograph of the surface of the manganese oxide layer of Example 3. FIG. 図７は、実施例３の充放電プロファイルである。FIG. 7 is a charge / discharge profile of Example 3. 図８は、実施例４のマンガン酸化物層表面のＳＥＭ写真である。FIG. 8 is a SEM photograph of the surface of the manganese oxide layer of Example 4. 図９は、実施例４の充放電プロファイルである。FIG. 9 is a charge / discharge profile of Example 4. 図１０は、実施例５のマンガン酸化物層表面のＳＥＭ写真である。FIG. 10 is an SEM photograph of the surface of the manganese oxide layer of Example 5. 図１１は、実施例５の充放電プロファイルである。FIG. 11 is a charge / discharge profile of Example 5. 図１２は、比較例１のマンガン酸化物層表面のＳＥＭ写真である。FIG. 12 is a SEM photograph of the surface of the manganese oxide layer of Comparative Example 1. 図１３は、比較例１の充放電プロファイルである。FIG. 13 is a charge / discharge profile of Comparative Example 1. 図１４は、比較例２のマンガン酸化物層表面のＳＥＭ写真である。FIG. 14 is an SEM photograph of the surface of the manganese oxide layer of Comparative Example 2. 図１５は、比較例２の充放電プロファイルである。FIG. 15 is a charge / discharge profile of Comparative Example 2.
　本発明の非水電解液電池用電極は、非水電解液を用いた電池に用いられる電極であって、基材の上に、電解処理により形成されたマンガン酸化物層を有し、前記マンガン酸化物層が表面に凹凸形状を有することを特徴とする。 The electrode for a non-aqueous electrolyte battery of the present invention is an electrode used for a battery using a non-aqueous electrolyte, and has a manganese oxide layer formed by electrolytic treatment on a substrate, and the manganese The oxide layer has an uneven shape on the surface.
　基材としては、特に限定されず、導電性を有するものであれば何でも使用することができるが、たとえば、本発明の非水電解液電池用電極を、リチウムイオン電池用の正極として用いる場合には、基材の耐食性の観点から、アルミニウム、アルミニウム合金、あるいは炭素材料からなるものなどを用いることが好ましい。これらのなかでも、マンガン酸化物層を良好に形成することができるという観点より、基材としては、アルミニウム箔、アルミニウム合金箔、または炭素繊維が好ましく用いられる。あるいは、基材としては、アルミニウム箔あるいはアルミニウム合金箔上に、炭素材料を含有する塗料を塗布することにより形成される炭素被覆アルミニウムを用いることもできる。 The substrate is not particularly limited, and any material can be used as long as it has conductivity. For example, when the nonaqueous electrolyte battery electrode of the present invention is used as a positive electrode for a lithium ion battery. From the viewpoint of the corrosion resistance of the substrate, it is preferable to use aluminum, an aluminum alloy, or a carbon material. Among these, aluminum foil, aluminum alloy foil, or carbon fiber is preferably used as the base material from the viewpoint that the manganese oxide layer can be satisfactorily formed. Or as a base material, the carbon covering aluminum formed by apply | coating the coating material containing a carbon material on aluminum foil or aluminum alloy foil can also be used.
　マンガン酸化物層は、上述した基材に、電解処理を行うことにより形成され、かつ、その表面に凹凸形状を有するものである。本発明は、マンガン酸化物層を、電解処理により形成させ、かつ、その表面に凹凸形状を有するものとするものであり、これにより、非水電解液電池用の電極として用いた場合における、放電容量を高くすることが可能となる。なお、マンガン酸化物層を形成するためのマンガン酸化物としては特に限定されないが、放電容量をより高くすることができるという点より、二酸化マンガン（ＭｎＯ２）が好ましい。 The manganese oxide layer is formed by performing electrolytic treatment on the above-described base material, and has a concavo-convex shape on the surface thereof. The present invention is a method in which a manganese oxide layer is formed by electrolytic treatment and has a concavo-convex shape on the surface thereof. As a result, when used as an electrode for a non-aqueous electrolyte battery, The capacity can be increased. Although not particularly limited as manganese oxide to form a manganese oxide layer, from the viewpoint that it is possible to increase the discharge capacity of manganese dioxide (MnO 2) is preferred.
　また、マンガン酸化物層としては、その表面に凹凸形状を有するものであればよいが、放電容量をより高くすることができるという点より、マンガン酸化物層としては、マンガン酸化物粒子が凝集することにより構成された二次粒子で形成され、かつ、その表面に、該二次粒子によって形成された連続した凹凸形状を有するものが特に好ましい。なお、本発明において、「マンガン酸化物層の表面が、二次粒子によって形成された連続した凹凸形状を有している状態」とは、二次粒子の形状に起因する凹凸形状が、平面状に連続して形成されている状態を意味し、特に、その表面において、平坦となっている部分が実質的に存在せずに、表面全体に亘って、連続して凹凸形状が形成されている状態が形成されていることが好ましい。本発明においては、マンガン酸化物層を、マンガン酸化物粒子が凝集することにより構成された二次粒子で形成されたものとし、かつ、その表面に、該二次粒子によって形成された連続した凹凸形状を有するものとすることにより、マンガン酸化物粒子の反応面積（比表面積）を効率的に高めることができ、これにより、非水電解液電池用の電極として用いた場合における、放電容量をより高めることができる。 Further, the manganese oxide layer only needs to have a concavo-convex shape on its surface, but the manganese oxide layer aggregates manganese oxide particles from the viewpoint that the discharge capacity can be further increased. It is particularly preferable to be formed of secondary particles constituted by the above and having a continuous uneven shape formed of the secondary particles on the surface thereof. In the present invention, the “state in which the surface of the manganese oxide layer has a continuous uneven shape formed by the secondary particles” means that the uneven shape resulting from the shape of the secondary particles is planar. In particular, in the surface, there is substantially no flat portion on the surface, and an uneven shape is continuously formed over the entire surface. It is preferable that a state is formed. In the present invention, the manganese oxide layer is formed of secondary particles formed by agglomeration of manganese oxide particles, and continuous irregularities formed on the surface by the secondary particles. By having the shape, the reaction area (specific surface area) of the manganese oxide particles can be efficiently increased, thereby further increasing the discharge capacity when used as an electrode for a non-aqueous electrolyte battery. Can be increased.
　また、マンガン酸化物層を形成する二次粒子としては、一次粒子としてのマンガン酸化物粒子が凝集することで形成されたものであればよく、一次粒子としてのマンガン酸化物粒子が凝集してなる凝集粒子が、さらに凝集してなるものであってもよい。すなわち、二次粒子としては、一次粒子としてのマンガン酸化物粒子が凝集してなる凝集粒子した粒子が、さらに凝集することで形成されたものであってもよい。 In addition, the secondary particles forming the manganese oxide layer may be formed by aggregation of manganese oxide particles as primary particles, and the manganese oxide particles as primary particles are aggregated. The aggregated particles may be further aggregated. That is, the secondary particles may be formed by further aggregating aggregated particles obtained by agglomerating manganese oxide particles as primary particles.
　なお、マンガン酸化物層の表面に形成される、二次粒子によって形成された連続した凹凸形状としては、その具体的な形状は、特に限定されるものではないが、たとえば、長さ１０μｍあたりに、二次粒子により形成された凸部を４個以上有するものが好ましい。なお、長さ１０μｍあたりにおける、二次粒子により形成された凸部の数の上限としては、特に限定されないが、通常、１００個以下である。凹凸形状に伴う凸部の数を上記範囲に制御することにより、マンガン酸化物層表面を十分に微細化することができ、これにより、活物質としてのマンガン酸化物の反応面積（比表面積）を十分高めることができ、結果として、非水電解液電池用の電極として用いた場合における、放電容量をより高めることができる。 In addition, as a continuous uneven | corrugated shape formed with the secondary particle formed in the surface of a manganese oxide layer, the specific shape is not specifically limited, For example, per 10 micrometers in length Those having four or more convex portions formed of secondary particles are preferable. In addition, although it does not specifically limit as an upper limit of the number of the convex parts formed with the secondary particle per 10 micrometers in length, Usually, it is 100 or less. By controlling the number of protrusions associated with the concavo-convex shape within the above range, the surface of the manganese oxide layer can be sufficiently miniaturized, thereby reducing the reaction area (specific surface area) of the manganese oxide as the active material. As a result, the discharge capacity when used as an electrode for a nonaqueous electrolyte battery can be further increased.
　なお、長さ１０μｍあたりの凸部の数の測定方法としては、特に限定されないが、たとえば、マンガン酸化物層について、集束イオンビーム（ＦＩＢ）装置により厚み方向の切断面を得て、得られた切断面について、倍率１００００倍にてＳＥＭ写真の撮影を行い、得られた倍率１００００倍のＳＥＭ写真上に平行に２本線を引き、２本の線内および２本の線近傍に位置する凸部の数をカウントするという操作を、５箇所について行い、得られた結果を平均することにより求めることができる。なお、凸部の数をカウントする際には、倍率１００００倍のＳＥＭ写真中において、凸部を形成していると判断できる部分を凸部として判断し、これをカウントする方法を採用すればよい。また、集束イオンビーム（ＦＩＢ）装置により得られた切断面のＳＥＭ写真を用いる方法に代えて、切断面を形成していない試料のＳＥＭ写真を得て、得られたＳＥＭ写真を用いて、凸部の数を求めてもよい。なお、この際、凸部を見えやすくするために試料を載置した試料台を４０～６０°程度傾けた状態でＳＥＭ写真を得てもよい。図１に、凸部の数のカウント用のマンガン酸化物層の表面のＳＥＭ写真の一例を示す。なお、図１は、後述する実施例５のマンガン酸化物層の表面のＳＥＭ写真（斜め方向から見た写真）であり、図１中においては、凸部のカウントに用いた２本の線も併せて示している。 The method for measuring the number of convex portions per 10 μm in length is not particularly limited. For example, the manganese oxide layer was obtained by obtaining a cut surface in the thickness direction with a focused ion beam (FIB) apparatus. Concerning the cut surface, an SEM photograph was taken at a magnification of 10000 times, and two lines were drawn in parallel on the obtained SEM photograph at a magnification of 10000 times, and a convex portion located in and near the two lines It is possible to obtain the result by performing the operation of counting the number of points at five places and averaging the obtained results. In addition, when counting the number of convex portions, it is only necessary to adopt a method of determining, as a convex portion, a portion that can be determined as forming a convex portion in an SEM photograph at a magnification of 10,000 times. . Further, instead of using the SEM photograph of the cut surface obtained by the focused ion beam (FIB) apparatus, an SEM photograph of the sample on which the cut surface is not formed is obtained, and the obtained SEM photograph is used. The number of parts may be obtained. At this time, an SEM photograph may be obtained in a state where the sample stage on which the sample is placed is tilted by about 40 to 60 ° so that the convex portion can be easily seen. In FIG. 1, an example of the SEM photograph of the surface of the manganese oxide layer for counting the number of convex parts is shown. FIG. 1 is a SEM photograph (photo seen from an oblique direction) of the surface of the manganese oxide layer of Example 5 described later. In FIG. 1, two lines used for counting the convex portions are also shown. It also shows.
　さらに、本発明においては、マンガン酸化物層を構成するマンガン酸化物粒子の形状としては、特に限定されないが、針状形状を有するものが好ましく、このような針状形状のマンガン酸化物粒子が凝集することにより二次粒子を構成していることがより好ましい。すなわち、針状の一次粒子が凝集することで、粒子状の二次粒子が形成されたものであることが好ましい。このように、マンガン酸化物層を構成するマンガン酸化物粒子を、針状形状を有するものとすることにより、マンガン酸化物粒子の反応面積（比表面積）を効率的に高めることができ、これにより、非水電解液電池用の電極として用いた場合における、放電容量をより高めることができる。 Furthermore, in the present invention, the shape of the manganese oxide particles constituting the manganese oxide layer is not particularly limited, but those having an acicular shape are preferred, and such acicular shaped manganese oxide particles are aggregated. It is more preferable to constitute secondary particles by doing so. That is, it is preferable that the acicular primary particles are aggregated to form particulate secondary particles. Thus, the reaction area (specific surface area) of manganese oxide particles can be increased efficiently by making the manganese oxide particles constituting the manganese oxide layer have a needle-like shape. When used as an electrode for a non-aqueous electrolyte battery, the discharge capacity can be further increased.
　針状のマンガン酸化物粒子としては、針状形状を有するものであればよく特に限定されないが、アスペクト比が、「短径：長径」の比で、好ましくは１：３～１：１００、より好ましくは１：５～１：５０、さらに好ましくは１：１０～１：５０である。アスペクト比をこの範囲にすることにより、充放電を繰り返し行った際の安定性を十分に確保しながら、マンガン酸化物粒子の比表面積を効率的に高めることができる。なお、針状のマンガン酸化物粒子のアスペクト比の測定方法としては、特に限定されないが、たとえば、マンガン酸化物層の表面について走査型電子顕微鏡（ＳＥＭ）を用いてＳＥＭ写真の撮影を行い、得られたＳＥＭ写真中において、針状のマンガン酸化物粒子を任意に１００個抽出し、１００個の針状のマンガン酸化物粒子についてアスペクト比の測定を行い、得られた測定結果を平均することにより求めることができる。 The acicular manganese oxide particles are not particularly limited as long as they have an acicular shape, but the aspect ratio is a ratio of “minor axis: major axis”, preferably 1: 3 to 1: 100. The ratio is preferably 1: 5 to 1:50, more preferably 1:10 to 1:50. By setting the aspect ratio within this range, it is possible to efficiently increase the specific surface area of the manganese oxide particles while sufficiently ensuring stability when charging and discharging are repeated. The method for measuring the aspect ratio of the acicular manganese oxide particles is not particularly limited. For example, the surface of the manganese oxide layer is obtained by taking a SEM photograph using a scanning electron microscope (SEM). In the obtained SEM photograph, by arbitrarily extracting 100 acicular manganese oxide particles, measuring the aspect ratio of 100 acicular manganese oxide particles, and averaging the obtained measurement results Can be sought.
　マンガン酸化物層の厚みは、特に限定されないが、好ましくは０．５～４０μｍ、より好ましくは１～２５μｍである。マンガン酸化物層の厚みが薄すぎると、マンガン酸化物の総量が少なすぎるために総容量が低下してしまうおそれがあり、一方、マンガン酸化物層の厚みが厚すぎると、レート特性が低下してしまうおそれがある。 The thickness of the manganese oxide layer is not particularly limited, but is preferably 0.5 to 40 μm, more preferably 1 to 25 μm. If the thickness of the manganese oxide layer is too thin, the total amount of manganese oxide may be too small and the total capacity may be reduced. On the other hand, if the thickness of the manganese oxide layer is too thick, the rate characteristics will decrease. There is a risk that.
　次いで、本発明の非水電解液電池用電極の製造方法について説明する。
　本発明の非水電解液電池用電極は、基材に対して、電解処理を行い、基材上に、上述した所定の微細構造を有するマンガン酸化物層を形成することにより得ることができる。具体的には、以下に例示するめっき浴を用い、以下の条件において、基材に対して、電気めっきを行うことにより、上述した所定の微細構造を有するマンガン酸化物層を形成することができる。なお、以下においては、マンガン酸化物層を形成するためのマンガン酸化物を、二酸化マンガン（ＭｎＯ２）とする場合を例示して説明する。 Subsequently, the manufacturing method of the electrode for nonaqueous electrolyte batteries of this invention is demonstrated.
The electrode for a non-aqueous electrolyte battery of the present invention can be obtained by subjecting a base material to an electrolytic treatment and forming a manganese oxide layer having the above-mentioned predetermined microstructure on the base material. Specifically, a manganese oxide layer having the above-described predetermined microstructure can be formed by performing electroplating on the substrate under the following conditions using a plating bath exemplified below. . In the following, a case where the manganese oxide for forming the manganese oxide layer is manganese dioxide (MnO 2 ) will be described as an example.
　めっき浴としては、２価のＭｎイオンを供給可能なＭｎ金属塩の水溶液であればよく、特に限定されないが、たとえば、硫酸マンガン浴（ＭｎＳＯ４）、塩化マンガン浴（ＭｎＣｌ２）、硝酸マンガン浴（Ｍｎ（ＮＯ３）２）、酢酸マンガン浴（（ＣＨ３ＣＯＯ）２Ｍｎ）などを用いることができる。これらのなかでも、次の理由から、硫酸マンガン浴および塩化マンガン浴が好ましい。硫酸マンガン浴および塩化マンガン浴は作業取扱い性が良好であり、また、特に、得られるマンガン酸化物層の微細構造を高度に制御することが可能であり、これにより、得られる非水電解液電池用電極の放電容量をより高くすることができる。さらに硫酸マンガン浴および塩化マンガン浴を用いることにより、得られるマンガン酸化物層中に含まれる一次粒子としてのマンガン酸化物粒子の針状化を促進し、これにより、得られる非水電解液電池用電極の放電容量をより高くすることができるため好ましく、特に塩化マンガン浴を用いた場合この効果が顕著に現れるため好ましい。 The plating bath may be a divalent Mn aqueous ions can be supplied Mn metal salt is not particularly limited, for example, manganese bath sulfate (MnSO 4), manganese chloride bath (MnCl 2), manganese nitrate bath (Mn (NO 3 ) 2 ), manganese acetate bath ((CH 3 COO) 2 Mn), or the like can be used. Among these, a manganese sulfate bath and a manganese chloride bath are preferable for the following reasons. Manganese sulfate bath and manganese chloride bath have good workability and, in particular, the microstructure of the resulting manganese oxide layer can be controlled to a high degree, and the resulting non-aqueous electrolyte battery The discharge capacity of the working electrode can be further increased. Further, by using a manganese sulfate bath and a manganese chloride bath, it promotes acicularization of manganese oxide particles as primary particles contained in the obtained manganese oxide layer, and thereby, for the obtained non-aqueous electrolyte battery This is preferable because the discharge capacity of the electrode can be further increased, and particularly when a manganese chloride bath is used, this effect is remarkable, which is preferable.
　めっき浴中のＭｎイオン濃度は、好ましくは０．０５～３．０ｍｏｌ／ｌの範囲であり、より好ましくは０．１～０．７ｍｏｌ／ｌの範囲である。めっき浴中のＭｎイオン濃度が０．０５ｍｏｌ／ｌ未満であると、めっきの析出が不安定になるおそれがある。一方、めっき浴中のＭｎイオン濃度を３．０ｍｏｌ／ｌ超としても、３．０ｍｏｌ／ｌ以下である場合と、めっきの析出挙動に大きな差が生じないため、製造コストや作業取扱い性の観点より、３．０ｍｏｌ／ｌ以下とすることが好ましい。 The Mn ion concentration in the plating bath is preferably in the range of 0.05 to 3.0 mol / l, more preferably in the range of 0.1 to 0.7 mol / l. If the Mn ion concentration in the plating bath is less than 0.05 mol / l, plating deposition may become unstable. On the other hand, even if the Mn ion concentration in the plating bath exceeds 3.0 mol / l, there is no significant difference in the deposition behavior of the plating from the case where it is 3.0 mol / l or less. Therefore, it is preferably 3.0 mol / l or less.
　さらに、めっき浴の温度は、好ましくは１５～５０℃、より好ましくは２０～４０℃である。めっき浴の温度が１５℃未満であると、めっきの析出速度が著しく低下してしまうおそれがあり、一方、５０℃を超えると、マンガン酸化物層中において、粒子の粗大化が起こってしまい、放電容量が低下するおそれがある。 Furthermore, the temperature of the plating bath is preferably 15 to 50 ° C., more preferably 20 to 40 ° C. If the temperature of the plating bath is less than 15 ° C., the deposition rate of the plating may be significantly reduced. On the other hand, if it exceeds 50 ° C., coarsening of particles occurs in the manganese oxide layer, The discharge capacity may be reduced.
　また、電気めっきを行う際には、カソード電解およびアノード電解のいずれでもよく、さらに、定電流電解あるいは定電圧電解のいずれでもよく、また、波形（矩形波、三角波）制御による定電流電解あるいは定電圧電解でもよいが、上述した所定の微細構造を有するマンガン酸化物層を良好に形成できるという観点より、アノード定電流電解が好ましい。 Further, when performing electroplating, either cathodic electrolysis or anodic electrolysis may be used, and further, either constant current electrolysis or constant voltage electrolysis may be used, and constant current electrolysis or constant electrolysis with waveform (rectangular wave, triangular wave) control may be used. Although voltage electrolysis may be used, anode constant current electrolysis is preferable from the viewpoint that the above-described manganese oxide layer having a predetermined fine structure can be satisfactorily formed.
　アノード定電流電解により電気めっきを行う場合における、電流密度は、好ましくは０．０１～４Ａ／ｄｍ２であり、より好ましくは０．０３～１Ａ／ｄｍ２である。本発明においては、電流密度を低くするほど、マンガン酸化物層の凹凸構造をより微細にすることができる一方で、電流密度が０．０１Ａ／ｄｍ２未満であると、長時間のめっきが必要となり、めっきの析出が不安定となってしまうため、好ましくない。また、本発明においては、電流密度が４Ａ／ｄｍ２超であると、マンガン酸化物層を構成する粒子が肥大化してしまい、上述した所定の微細構造を有するマンガン酸化物層が得られなくなってしまう。 When electroplating is performed by anodic constant current electrolysis, the current density is preferably 0.01 to 4 A / dm 2 , more preferably 0.03 to 1 A / dm 2 . In the present invention, as the current density is lowered, the uneven structure of the manganese oxide layer can be made finer. On the other hand, if the current density is less than 0.01 A / dm 2 , long time plating is required. Then, the deposition of the plating becomes unstable, which is not preferable. In the present invention, if the current density is more than 4 A / dm 2 , the particles constituting the manganese oxide layer are enlarged, and the manganese oxide layer having the predetermined microstructure described above cannot be obtained. End up.
　以上のような条件で、電気めっきを行うことにより、本発明によれば、上述した所定の微細構造を有するマンガン酸化物層を形成することができる。特に、本発明においては、電気めっきを以上のような条件で行うことにより、得られるマンガン酸化物層中に含まれる一次粒子としてのマンガン酸化物粒子の針状化を促進し、これにより、得られる非水電解液電池用電極の放電容量をより高くすることができるため、好ましい。 By performing electroplating under the conditions as described above, according to the present invention, the manganese oxide layer having the predetermined fine structure described above can be formed. In particular, in the present invention, by performing electroplating under the above conditions, acicularization of manganese oxide particles as primary particles contained in the obtained manganese oxide layer is promoted. This is preferable because the discharge capacity of the nonaqueous electrolyte battery electrode can be increased.
　そして、このようにして得られる本発明の非水電解液電池用電極は、たとえば、リチウムイオン二次電池や一次電池などの非水電解液電池用の電極、特に、正極として好適に用いることができる。すなわち、リチウムイオン二次電池を例示して説明すると、本発明の非水電解液電池用電極を正極とし、リチウムをドープおよび脱ドープすることが可能な活物質（たとえば、金属リチウムや各種カーボン材料）を備えた負極を、セパレータを介して積層することで電極積層体を形成し、得られた電極積層体に非水電解液を含浸させ、必要に応じて容器内に密封することで、リチウムイオン二次電池を得ることができる。なお、この場合においては、本発明の非水電解液電池用電極に対して、必要に応じて、予めリチウムをドープさせておくプレドープ処理を行ってもよい。 The nonaqueous electrolyte battery electrode of the present invention thus obtained can be suitably used as an electrode for a nonaqueous electrolyte battery such as a lithium ion secondary battery or a primary battery, particularly as a positive electrode. it can. That is, a lithium ion secondary battery will be described as an example. An active material (for example, metallic lithium or various carbon materials) capable of doping and dedoping lithium with the nonaqueous electrolyte battery electrode of the present invention as a positive electrode. ) Is laminated via a separator, an electrode laminate is formed, the resulting electrode laminate is impregnated with a non-aqueous electrolyte, and sealed in a container as necessary, so that lithium An ion secondary battery can be obtained. In this case, the non-aqueous electrolyte battery electrode of the present invention may be subjected to a pre-doping treatment in which lithium is doped in advance if necessary.
　非水電解液としては、特に限定されないが、有機溶媒に支持電解質を溶解した有機電解液が用いられる。支持電解質としては、たとえば、リチウム塩が用いられ、リチウム塩としては、ＬｉＰＦ６、ＬｉＡｓＦ６、ＬｉＢＦ４、ＬｉＳｂＦ６、ＬｉＡｌＣｌ４、ＬｉＣｌＯ４、ＣＦ３ＳＯ３Ｌｉ、Ｃ４Ｆ９ＳＯ３Ｌｉ、ＣＦ３ＣＯＯＬｉ、（ＣＦ３ＣＯ）２ＮＬｉ、（ＣＦ３ＳＯ２）２ＮＬｉ、（Ｃ２Ｆ５ＳＯ２）ＮＬｉなどが挙げられる。 The nonaqueous electrolytic solution is not particularly limited, but an organic electrolytic solution in which a supporting electrolyte is dissolved in an organic solvent is used. As the supporting electrolyte, for example, lithium salt is used as the lithium salt, LiPF 6, LiAsF 6, LiBF 4, LiSbF 6, LiAlCl 4, LiClO 4, CF 3 SO 3 Li, C 4 F 9 SO 3 Li, CF 3 COOLi, (CF 3 CO) 2 NLi, (CF 3 SO 2 ) 2 NLi, (C 2 F 5 SO 2 ) NLi, and the like can be given.
　有機溶媒としては、支持電解質を溶解できるものであれば特に限定されないが、ジメチルカーボネート（ＤＭＣ）、エチレンカーボネート（ＥＣ）、ジエチルカーボネート（ＤＥＣ）、プロピレンカーボネート（ＰＣ）、ブチレンカーボネート（ＢＣ）、メチルエチルカーボネート（ＭＥＣ）、ビニレンカーボネート（ＶＣ）などのカーボネート類；γ－ブチロラクトン、ギ酸メチルなどのエステル類；１，２－ジメトキシエタン（ＤＭＥ）、テトラヒドロフランなどのエーテル類；スルホラン、ジメチルスルホキシドなどの含硫黄化合物類；などが挙げられる。なお、これら有機溶媒は、単独で用いてもよいし、２つ以上を組み合わせて用いてもよい。 The organic solvent is not particularly limited as long as it can dissolve the supporting electrolyte, but dimethyl carbonate (DMC), ethylene carbonate (EC), diethyl carbonate (DEC), propylene carbonate (PC), butylene carbonate (BC), methyl Carbonates such as ethyl carbonate (MEC) and vinylene carbonate (VC); esters such as γ-butyrolactone and methyl formate; ethers such as 1,2-dimethoxyethane (DME) and tetrahydrofuran; Sulfur compounds; and the like. In addition, these organic solvents may be used independently and may be used in combination of 2 or more.
　本発明によれば、非水電解液電池用電極を構成する、活物質層としてのマンガン酸化物層を、電解処理により形成するものであるため、活物質層としてのマンガン酸化物層を、実質的に、活物質であるマンガン酸化物のみからなるものとすることができ、これにより、単位重量および単位体積当たりの放電容量を高めることができる。すなわち、本発明によれば、活物質層としてのマンガン酸化物層を形成する際に、電池容量に寄与しないバインダや導電性カーボンなどを配合する必要が無いため、これら電池容量に寄与しないバインダや導電性カーボンを配合することによる、放電容量の低下が起こらないため、結果として、単位重量および単位体積当たりの放電容量を高めることができる。 According to the present invention, the manganese oxide layer as the active material layer that constitutes the electrode for the non-aqueous electrolyte battery is formed by electrolytic treatment. Therefore, the manganese oxide layer as the active material layer is substantially In particular, it can be made only of a manganese oxide as an active material, thereby increasing the unit weight and the discharge capacity per unit volume. That is, according to the present invention, when forming the manganese oxide layer as the active material layer, there is no need to blend a binder that does not contribute to battery capacity, conductive carbon, or the like. Since the discharge capacity is not reduced by adding conductive carbon, the discharge capacity per unit weight and unit volume can be increased as a result.
　また、本発明によれば、活物質層としてのマンガン酸化物層を、電解処理により形成することにより、基材とマンガン酸化物層との界面の密着性を高くすることができ、これにより、電極としての耐久性を優れたものとすることもできる。特に、従来のように、塗布法により、活物質層としてのマンガン酸化物層を形成した場合には、バインダの接着力により、マンガン酸化物層を基材に保持するものであるため、基材とマンガン酸化物層との間の密着性は十分ではなく、長期使用時に剥離が生じやすいという不具合がある。これに対して、本発明によれば、マンガン酸化物層を、電解処理により形成することにより、このような問題を有効に解決することができるものである。 In addition, according to the present invention, by forming the manganese oxide layer as the active material layer by electrolytic treatment, the adhesion at the interface between the base material and the manganese oxide layer can be increased. The durability as an electrode can also be made excellent. In particular, when a manganese oxide layer as an active material layer is formed by a coating method as in the prior art, the manganese oxide layer is held on the substrate by the adhesive force of the binder. There is a problem that the adhesion between the silicon oxide layer and the manganese oxide layer is not sufficient, and peeling tends to occur during long-term use. On the other hand, according to the present invention, such a problem can be effectively solved by forming the manganese oxide layer by electrolytic treatment.
　さらに、本発明によれば、活物質層としてのマンガン酸化物層を、その表面に凹凸形状を有するものとすることにより、活物質としてのマンガン酸化物の反応面積（比表面積）を増大させることができる。そして、これにより、マンガン酸化物層中に含まれるマンガン酸化物の反応利用率を上げることができ、結果として、単位重量および単位体積当たりの放電容量を高めることができる。特に、従来のように、塗布法により、活物質層としてのマンガン酸化物層を形成した場合には、活物質としてのマンガン酸化物の微細化には限界があり、そのため、マンガン酸化物の反応面積を向上させることができず、結果として、放電容量が低くなってしまうという不具合があった。これに対し、本発明によれば、このような不具合を有効に解決することができるものである。また、本発明によれば、単位重量および単位体積当たりの放電容量を高めることができることから、電池の設計上、従来と同程度の放電容量で十分な場合には、正極の厚みを薄くすることができるため、これにより、電池全体の薄型化を達成することもできる。 Furthermore, according to the present invention, the reaction area (specific surface area) of the manganese oxide as the active material is increased by making the surface of the manganese oxide layer as the active material layer have an uneven shape. Can do. And thereby, the reaction utilization factor of the manganese oxide contained in a manganese oxide layer can be raised, As a result, the discharge capacity per unit weight and unit volume can be raised. In particular, when a manganese oxide layer as an active material layer is formed by a coating method as in the prior art, there is a limit to the miniaturization of manganese oxide as an active material. There was a problem that the area could not be improved, and as a result, the discharge capacity was lowered. On the other hand, according to the present invention, such a problem can be effectively solved. Also, according to the present invention, the discharge capacity per unit weight and unit volume can be increased. Therefore, when the discharge capacity of the same level as the conventional one is sufficient in the battery design, the thickness of the positive electrode is reduced. Therefore, the overall thickness of the battery can be reduced.
　以下に、実施例を挙げて、本発明についてより具体的に説明するが、本発明は、これら実施例に限定されない。 Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.
《実施例１》
　基材としての炭素繊維（「ＰｙＲＯＦＩＬ ＧＤＬ」、三菱レイヨン社製、厚み０．２ｍｍ、１４ｍｍφに打ち抜いたもの）に、市販試薬特級の塩化マンガン（ＩＩ）四水和物を０．５ｍｏｌ／ｌとなるように純水に溶解させることにより得られためっき浴を用いて、炭素繊維をアノードとし、以下の条件で、アノード定電流電解により、電気めっきを行うことで、炭素繊維の表面に二酸化マンガン（ＭｎＯ２）からなる層を形成することで、正極を得た。なお、得られた二酸化マンガンからなる層は、重量１．８ｍｇであり、重量法による膜厚で２．３２μｍに相当するものであった。
　　めっき浴：０．５Ｍ　塩化マンガン水溶液（浴温：４０℃、ｐＨ：３．０）
　　電流印加方式：アノード定電流電解
　　アノード電流密度：０．０５Ａ／ｄｍ２
　　アノード通電量：４０Ｃ（／１６ｃｍ２）
　　カソード：白金板
　なお、二酸化マンガンからなる層の膜厚は、電気めっき前後の重量変化より、二酸化マンガンからなる層の重量を求め、得られた重量と、基材の表面積と、二酸化マンガンの密度（５．０３ｇ／ｃｍ３）とから、重量法により算出した。 Example 1
Carbon fiber ("PyROFIL GDL", manufactured by Mitsubishi Rayon Co., Ltd., punched to a thickness of 0.2 mm, 14 mmφ) as a base material, 0.5 mol / l of a commercially available reagent-grade manganese (II) chloride tetrahydrate Using a plating bath obtained by dissolving in pure water, carbon fiber is used as an anode, and electroplating is performed by anode constant current electrolysis under the following conditions, whereby manganese dioxide is deposited on the surface of the carbon fiber. A positive electrode was obtained by forming a layer made of (MnO 2 ). The obtained layer made of manganese dioxide weighed 1.8 mg and was equivalent to 2.32 μm by a gravimetric method.
Plating bath: 0.5M manganese chloride aqueous solution (bath temperature: 40 ° C., pH: 3.0)
Current application method: anode constant current electrolysis anode current density: 0.05 A / dm 2
Anode energization amount: 40 C (/ 16 cm 2 )
Cathode: Platinum plate In addition, the film thickness of the layer made of manganese dioxide is obtained by determining the weight of the layer made of manganese dioxide from the weight change before and after electroplating, and the obtained weight, the surface area of the base material, and the density of manganese dioxide From (5.03 g / cm 3 ), the weight was calculated.
　そして、上記にて得られた正極の二酸化マンガンからなる層の表面について、走査型電子顕微鏡を用いて、ＳＥＭ写真の撮影を行った。二酸化マンガンからなる層の表面のＳＥＭ写真を、図２（Ａ）および図２（Ｂ）に示す。２万倍の写真である図２（Ｂ）から明らかなように、得られた二酸化マンガンからなる層は、針状のマンガン酸化物粒子が凝集することにより構成された二次粒子で形成されてなるものであることが確認された。なお、本実施例においては、図２（Ａ）に示す５０００倍のＳＥＭ写真は、観察電圧（加速電圧）１５ｋＶの条件で、図２（Ｂ）に示す２万倍のＳＥＭ写真は、観察電圧（加速電圧）３ｋＶの条件で、それぞれ撮影した（後述する実施例２～５、比較例１，２においても同様。）。５０００倍のＳＥＭ写真において、観察電圧（加速電圧）１５ｋＶとしたのは、観察電圧（加速電圧）を比較的高くすることで、二酸化マンガンからなる層の表面の立体形状を詳細に観察するためであり、また、２万倍のＳＥＭ写真において、観察電圧（加速電圧）３ｋＶとしたのは、観察電圧（加速電圧）を比較的低くすることで、二酸化マンガンからなる層の表面の微細構造を詳細に観察するためである。 Then, SEM photographs were taken on the surface of the layer made of manganese dioxide of the positive electrode obtained above using a scanning electron microscope. The SEM photograph of the surface of the layer which consists of manganese dioxide is shown to FIG. 2 (A) and FIG. 2 (B). As is apparent from FIG. 2B, which is a 20,000-fold photograph, the obtained manganese dioxide layer is formed of secondary particles formed by agglomeration of acicular manganese oxide particles. It was confirmed that In this example, the 5000 times SEM photograph shown in FIG. 2A is the observation voltage (acceleration voltage) 15 kV, and the 20,000 times SEM photograph shown in FIG. Images were taken under the condition of (acceleration voltage) 3 kV (the same applies to Examples 2 to 5 and Comparative Examples 1 and 2 described later). The reason why the observation voltage (acceleration voltage) is set to 15 kV in the SEM photograph of 5000 times is that the observation voltage (acceleration voltage) is relatively high, so that the three-dimensional shape of the surface of the layer made of manganese dioxide can be observed in detail. Yes, the observation voltage (acceleration voltage) of 3 kV in the SEM photograph of 20,000 times is that the observation voltage (acceleration voltage) is relatively low, and the fine structure of the surface of the layer made of manganese dioxide is detailed. It is for observing.
　また、得られたＳＥＭ写真を用いて、長さ１０μｍあたりの凸部の数、および針状のマンガン酸化物粒子のアスペクト比の測定を行った。結果を表１に示す。なお、長さ１０μｍあたりの凸部の数は、得られた二酸化マンガンからなる層について、走査型電子顕微鏡の本体内において、１００００倍のＳＥＭ写真の撮影を行い、得られた１００００倍のＳＥＭ写真について、ＳＥＭ写真上に平行に２本線を引き、２本の線内および２本の線近傍に位置する凸部の数をカウントするという操作を、５箇所について行い、得られた結果を平均することにより求めた。また、針状のマンガン酸化物粒子のアスペクト比は、二酸化マンガンからなる層の表面のＳＥＭ写真を用いて、任意の１００個の針状のマンガン酸化物粒子を抽出し、アスペクト比を測定し、得られた結果を平均することにより求めた。 Further, using the obtained SEM photograph, the number of convex portions per 10 μm length and the aspect ratio of acicular manganese oxide particles were measured. The results are shown in Table 1. In addition, the number of convex parts per 10 μm in length was obtained by taking a 10,000 times SEM photograph in the main body of the scanning electron microscope for the obtained layer of manganese dioxide, and obtaining a 10,000 times SEM photograph. With respect to the SEM photograph, two lines are drawn in parallel on the SEM photograph, and the operation of counting the number of convex portions located in the two lines and in the vicinity of the two lines is performed at five points, and the obtained results are averaged. Was determined by Further, the aspect ratio of the acicular manganese oxide particles is obtained by extracting 100 arbitrary acicular manganese oxide particles using the SEM photograph of the surface of the layer made of manganese dioxide, and measuring the aspect ratio. The obtained results were obtained by averaging.
　次いで、上記にて得られた正極と、負極としての金属リチウム（１５ｍｍφ、厚み０．３ｍｍ）とを、セパレータ（「セルガード＃２４００」、セルガード社製、１８ｍｍφ、厚み０．０２５ｍｍ）を介して積層し、ＳＵＳ３１６Ｌ製のコイン電池ケース内に収容し、電解液を添加した後に密閉することで、２０３２型コイン電地（直径２０ｍｍ×高さ３．２ｍｍ）を作製した。なお、電解液としては、「プロピレンカーボネート（ＰＣ）：１，２－ジメトキシエタン（ＤＭＥ）＝１：１（体積比）」に、１ｍｏｌ／ｌのＬｉＰＦ６を溶解したものを用いた。 Next, the positive electrode obtained above and metallic lithium (15 mmφ, thickness 0.3 mm) as a negative electrode are laminated via a separator (“Celguard # 2400”, manufactured by Celgard, 18 mmφ, thickness 0.025 mm). And it accommodated in the coin battery case made from SUS316L, and after adding electrolyte solution, it sealed, and produced the 2032 type coin electric field (diameter 20mm x height 3.2mm). As the electrolytic solution, a solution obtained by dissolving 1 mol / l LiPF 6 in “propylene carbonate (PC): 1,2-dimethoxyethane (DME) = 1: 1 (volume ratio)” was used.
　そして、上記にて得られたコイン電地を用いて、充電の上限電圧：４．２Ｖ（ｖｓ．Ｌｉ）、放電の下限電圧：１．５Ｖ（ｖｓ．Ｌｉ）、充放電レート：０．０３３Ｃの条件で５サイクルの充放電試験を行った。なお、本充放電試験においては、充放電試験器（「電池充放電装置ＳＤ８」、北斗電工社製）を用い、充電は定電流－定電圧方式にて行い、放電は定電流方式にて行った。充放電試験の結果得られた充放電プロファイルを図３に示す。また、５サイクルの充放電試験における平均放電容量を表１に示す。なお、図３および表１において、放電容量は、電極活物質層の単位重量当たりの容量を「ｍＡｈ／ｇ」で示している（後述する実施例２～５、比較例１，２においても同様。）。 And using the coin electric ground obtained above, the upper limit voltage of charge: 4.2V (vs. Li), the lower limit voltage of discharge: 1.5V (vs. Li), the charge / discharge rate: 0.033C Under these conditions, a 5-cycle charge / discharge test was conducted. In this charge / discharge test, a charge / discharge tester (“Battery Charge / Discharge Device SD8”, manufactured by Hokuto Denko Co., Ltd.) is used, and charging is performed by a constant current-constant voltage method, and discharging is performed by a constant current method. It was. The charge / discharge profile obtained as a result of the charge / discharge test is shown in FIG. Table 1 shows the average discharge capacity in a 5-cycle charge / discharge test. In FIG. 3 and Table 1, the discharge capacity indicates the capacity per unit weight of the electrode active material layer as “mAh / g” (the same applies to Examples 2 to 5 and Comparative Examples 1 and 2 described later). .)
《実施例２》
　基材としての炭素繊維（「ＰｙＲＯＦＩＬ ＧＤＬ」、三菱レイヨン社製、厚み０．２ｍｍ、１４ｍｍφに打ち抜いたもの）に、市販試薬特級の塩化マンガン（ＩＩ）四水和物を０．５ｍｏｌ／ｌとなるように純水に溶解させることにより得られためっき浴を用いて、炭素繊維をアノードとし、以下の条件で、アノード定電流電解により、電気めっきを行うことで、炭素繊維の表面に二酸化マンガン（ＭｎＯ２）からなる層を形成することで、正極を得た。なお、得られた二酸化マンガンからなる層は、重量４．２ｍｇであり、重量法による膜厚で５．４２μｍに相当するものであった。
　　めっき浴：０．５Ｍ　塩化マンガン水溶液（浴温：４０℃、ｐＨ：３．０）
　　電流印加方式：アノード定電流電解
　　アノード電流密度：０．０５Ａ／ｄｍ２
　　アノード通電量：１０４Ｃ（／１６ｃｍ２）
　　カソード：白金板 Example 2
Carbon fiber ("PyROFIL GDL", manufactured by Mitsubishi Rayon Co., Ltd., punched to a thickness of 0.2 mm, 14 mmφ) as a base material, 0.5 mol / l of a commercially available reagent-grade manganese (II) chloride tetrahydrate Using a plating bath obtained by dissolving in pure water, carbon fiber is used as an anode, and electroplating is performed by anode constant current electrolysis under the following conditions, whereby manganese dioxide is deposited on the surface of the carbon fiber. A positive electrode was obtained by forming a layer made of (MnO 2 ). In addition, the layer which consists of obtained manganese dioxide was 4.2 mg in weight, and was equivalent to 5.42 micrometers by the film thickness by a gravimetric method.
Plating bath: 0.5M manganese chloride aqueous solution (bath temperature: 40 ° C., pH: 3.0)
Current application method: anode constant current electrolysis anode current density: 0.05 A / dm 2
Anode energization amount: 104 C (/ 16 cm 2 )
Cathode: Platinum plate
　そして、上記にて得られた正極の二酸化マンガンからなる層の表面について、走査型電子顕微鏡を用いて、ＳＥＭ写真の撮影を行った。二酸化マンガンからなる層の表面のＳＥＭ写真を、図４（Ａ）および図４（Ｂ）に示す。２万倍の写真である図４（Ｂ）から明らかなように、得られた二酸化マンガンからなる層は、針状のマンガン酸化物粒子が凝集することにより構成された二次粒子で形成されてなるものであることが確認された。また、得られたＳＥＭ写真を用いて、実施例１と同様にして、長さ１０μｍあたりの凸部の数、および針状のマンガン酸化物粒子のアスペクト比の測定を行った。結果を表１に示す。 Then, SEM photographs were taken on the surface of the layer made of manganese dioxide of the positive electrode obtained above using a scanning electron microscope. The SEM photograph of the surface of the layer which consists of manganese dioxide is shown to FIG. 4 (A) and FIG. 4 (B). As is clear from FIG. 4B, which is a 20,000 times photograph, the obtained manganese dioxide layer is formed of secondary particles formed by aggregation of acicular manganese oxide particles. It was confirmed that Further, using the obtained SEM photograph, the number of convex portions per 10 μm length and the aspect ratio of acicular manganese oxide particles were measured in the same manner as in Example 1. The results are shown in Table 1.
　次いで、上記にて得られた正極を用いた以外は、実施例１と同様にして、コイン電地を作製し、同様に評価を行った。充放電試験の結果得られた充放電プロファイルを図５に、５サイクルの充放電試験における平均放電容量を表１に示す。 Next, a coin electric ground was prepared and evaluated in the same manner as in Example 1 except that the positive electrode obtained above was used. FIG. 5 shows the charge / discharge profile obtained as a result of the charge / discharge test, and Table 1 shows the average discharge capacity in the 5-cycle charge / discharge test.
《実施例３》
　基材としての炭素繊維（「ＰｙＲＯＦＩＬ ＧＤＬ」、三菱レイヨン社製、厚み０．２ｍｍ、１４ｍｍφに打ち抜いたもの）に、市販試薬特級の硫酸マンガン（ＩＩ）五水和物を０．５ｍｏｌ／ｌとなるように純水に溶解させることにより得られためっき浴を用いて、炭素繊維をアノードとし、以下の条件で、アノード定電流電解により、電気めっきを行うことで、炭素繊維の表面に二酸化マンガン（ＭｎＯ２）からなる層を形成することで、正極を得た。なお、得られた二酸化マンガンからなる層は、重量１．７ｍｇであり、重量法による膜厚で２．２０μｍに相当するものであった。
　　めっき浴：０．５Ｍ　硫酸マンガン水溶液（浴温：４０℃、ｐＨ：３．０）
　　電流印加方式：アノード定電流電解
　　アノード電流密度：０．０１Ａ／ｄｍ２
　　アノード通電量：２９Ｃ（／１６ｃｍ２）
　　カソード：白金板 Example 3
Carbon fiber (“PyROFIL GDL”, manufactured by Mitsubishi Rayon Co., Ltd., punched to a thickness of 0.2 mm, 14 mmφ) as a base material, 0.5 mol / l of a commercially available reagent-grade manganese (II) sulfate pentahydrate Using a plating bath obtained by dissolving in pure water, carbon fiber is used as an anode, and electroplating is performed by anode constant current electrolysis under the following conditions, whereby manganese dioxide is deposited on the surface of the carbon fiber. A positive electrode was obtained by forming a layer made of (MnO 2 ). In addition, the layer which consists of obtained manganese dioxide was 1.7 mg in weight, and was equivalent to 2.20 micrometers in the film thickness by a gravimetric method.
Plating bath: 0.5M manganese sulfate aqueous solution (bath temperature: 40 ° C., pH: 3.0)
Current application method: anode constant current electrolysis anode current density: 0.01 A / dm 2
Anode energization amount: 29 C (/ 16 cm 2 )
Cathode: Platinum plate
　そして、上記にて得られた正極の二酸化マンガンからなる層の表面について、走査型電子顕微鏡を用いて、ＳＥＭ写真の撮影を行った。二酸化マンガンからなる層の表面のＳＥＭ写真を、図６（Ａ）および図６（Ｂ）に示す。２万倍の写真である図６（Ｂ）から明らかなように、得られた二酸化マンガンからなる層は、針状のマンガン酸化物粒子が凝集することにより構成された二次粒子で形成されてなるものであることが確認された。また、得られたＳＥＭ写真を用いて、実施例１と同様にして、長さ１０μｍあたりの凸部の数、および針状のマンガン酸化物粒子のアスペクト比の測定を行った。結果を表１に示す。 Then, SEM photographs were taken on the surface of the layer made of manganese dioxide of the positive electrode obtained above using a scanning electron microscope. The SEM photograph of the surface of the layer which consists of manganese dioxide is shown to FIG. 6 (A) and FIG. 6 (B). As is clear from FIG. 6B, which is a 20,000-fold photograph, the obtained manganese dioxide layer is formed of secondary particles formed by agglomeration of acicular manganese oxide particles. It was confirmed that Further, using the obtained SEM photograph, the number of convex portions per 10 μm length and the aspect ratio of acicular manganese oxide particles were measured in the same manner as in Example 1. The results are shown in Table 1.
　次いで、上記にて得られた正極を用いた以外は、実施例１と同様にして、コイン電地を作製し、同様に評価を行った。充放電試験の結果得られた充放電プロファイルを図７に、５サイクルの充放電試験における平均放電容量を表１に示す。 Next, a coin electric ground was prepared and evaluated in the same manner as in Example 1 except that the positive electrode obtained above was used. FIG. 7 shows the charge / discharge profile obtained as a result of the charge / discharge test, and Table 1 shows the average discharge capacity in the 5-cycle charge / discharge test.
《実施例４》
　基材としての炭素繊維（「ＰｙＲＯＦＩＬ ＧＤＬ」、三菱レイヨン社製、厚み０．２ｍｍ、１４ｍｍφに打ち抜いたもの）に、市販試薬特級の硫酸マンガン（ＩＩ）五水和物を０．５ｍｏｌ／ｌとなるように純水に溶解させることにより得られためっき浴を用いて、炭素繊維をアノードとし、以下の条件で、波形制御による定電圧電解により、電気めっきを行うことで、炭素繊維の表面に二酸化マンガン（ＭｎＯ２）からなる層を形成することで、正極を得た。なお、得られた二酸化マンガンからなる層は、重量１．０ｍｇであり、重量法による膜厚で１．２９μｍに相当するものであった。
　　めっき浴：０．５Ｍ　硫酸マンガン水溶液（浴温：４０℃、ｐＨ：３．０）
　　電流印加方式：波形制御
　　アノード通電量：２９Ｃ（／１６ｃｍ２）
　　カソード：白金板
　なお、本例においては、波形制御による定電圧電解は、以下の条件による電位掃引法によるセル電圧制御により行った。
　　１ｓｔセル電圧：浸漬電位→１．８Ｖ（掃引速度４４０ｍＶ／ｓ）
　　２ｎｄセル電圧：１．８Ｖ→２．５Ｖ（掃引速度２９ｍＶ／ｓ）
　　３ｒｄセル電圧：２．５Ｖ→２．７Ｖ（掃引速度０．１ｍＶ／ｓ） Example 4
Carbon fiber (“PyROFIL GDL”, manufactured by Mitsubishi Rayon Co., Ltd., punched to a thickness of 0.2 mm, 14 mmφ) as a base material, 0.5 mol / l of a commercially available reagent-grade manganese (II) sulfate pentahydrate Using the plating bath obtained by dissolving in pure water, using carbon fiber as an anode and performing electroplating by constant voltage electrolysis under waveform control under the following conditions, the surface of carbon fiber is A positive electrode was obtained by forming a layer made of manganese dioxide (MnO 2 ). The obtained layer of manganese dioxide weighed 1.0 mg and was equivalent to 1.29 μm in weight by gravimetric method.
Plating bath: 0.5M manganese sulfate aqueous solution (bath temperature: 40 ° C., pH: 3.0)
Current application method: Waveform control Anode energization amount: 29 C (/ 16 cm 2 )
Cathode: Platinum plate In this example, constant voltage electrolysis by waveform control was performed by cell voltage control by a potential sweep method under the following conditions.
1st cell voltage: immersion potential → 1.8 V (sweep speed 440 mV / s)
2nd cell voltage: 1.8 V → 2.5 V (sweep speed 29 mV / s)
3rd cell voltage: 2.5 V → 2.7 V (sweep speed 0.1 mV / s)
　そして、上記にて得られた正極の二酸化マンガンからなる層の表面について、走査型電子顕微鏡を用いて、ＳＥＭ写真の撮影を行った。二酸化マンガンからなる層の表面のＳＥＭ写真を、ＳＥＭ写真の撮影を行った。得られたＳＥＭ写真を、図８（Ａ）および図８（Ｂ）に示す。２万倍の写真である図８（Ｂ）から明らかなように、針状のマンガン酸化物粒子が凝集することにより構成された二次粒子で形成されてなるもの（具体的には、針状のマンガン酸化物粒子が凝集してなる凝集粒子が、さらに凝集することにより構成された二次粒子で形成されてなるもの）であることが確認された。また、得られたＳＥＭ写真を用いて、実施例１と同様にして、長さ１０μｍあたりの凸部の数、および針状のマンガン酸化物粒子のアスペクト比の測定を行った。結果を表１に示す。 Then, SEM photographs were taken on the surface of the layer made of manganese dioxide of the positive electrode obtained above using a scanning electron microscope. The SEM photograph of the surface of the layer made of manganese dioxide was taken. The obtained SEM photographs are shown in FIGS. 8 (A) and 8 (B). As is apparent from FIG. 8 (B), which is a 20,000 times photograph, one formed by secondary particles constituted by aggregation of acicular manganese oxide particles (specifically, acicular It was confirmed that the agglomerated particles formed by agglomeration of the manganese oxide particles were formed by secondary particles formed by further agglomeration). Further, using the obtained SEM photograph, the number of convex portions per 10 μm length and the aspect ratio of acicular manganese oxide particles were measured in the same manner as in Example 1. The results are shown in Table 1.
　次いで、上記にて得られた正極を用いた以外は、実施例１と同様にして、コイン電地を作製し、同様に評価を行った。充放電試験の結果得られた充放電プロファイルを図９に、５サイクルの充放電試験における平均放電容量を表１に示す。 Next, a coin electric ground was prepared and evaluated in the same manner as in Example 1 except that the positive electrode obtained above was used. FIG. 9 shows the charge / discharge profile obtained as a result of the charge / discharge test, and Table 1 shows the average discharge capacity in the 5-cycle charge / discharge test.
《実施例５》
　基材としてのアルミニウム合金箔（Ａ３１０４，厚み２００μｍ、１４ｍｍφに打ち抜いたもの）に、市販試薬特級の硫酸マンガン（ＩＩ）五水和物を０．５ｍｏｌ／ｌとなるように純水に溶解させることにより得られためっき浴を用いて、アルミニウム合金箔をアノードとし、以下の条件で、アノード定電流電解により、電気めっきを行うことで、炭素繊維の表面に二酸化マンガン（ＭｎＯ２）からなる層を形成することで、正極を得た。なお、得られた二酸化マンガンからなる層は、重量０．２ｍｇであり、ＦＩＢ装置による厚み方向の切断面での実測による膜厚は１．５μｍであった。
　　めっき浴：０．５Ｍ　硫酸マンガン水溶液（浴温：４０℃、ｐＨ：３．０）
　　電流印加方式：アノード定電流電解
　　アノード電流密度：０．０５Ａ／ｄｍ２
　　アノード通電量：５７．６Ｃ（／１６ｃｍ２）
　　カソード：白金板 Example 5
Dissolve commercially available reagent-grade manganese (II) sulfate pentahydrate in pure water at 0.5 mol / l in an aluminum alloy foil (A3104, 200 μm thick, punched to 14 mmφ) as a base material A layer made of manganese dioxide (MnO 2 ) is formed on the surface of the carbon fiber by performing electroplating by anode constant current electrolysis under the following conditions using the aluminum alloy foil as an anode using the plating bath obtained by By forming, a positive electrode was obtained. The obtained manganese dioxide layer weighed 0.2 mg, and the film thickness measured on the cut surface in the thickness direction by the FIB apparatus was 1.5 μm.
Plating bath: 0.5M manganese sulfate aqueous solution (bath temperature: 40 ° C., pH: 3.0)
Current application method: anode constant current electrolysis anode current density: 0.05 A / dm 2
Anode energization amount: 57.6 C (/ 16 cm 2 )
Cathode: Platinum plate
　そして、上記にて得られた正極の二酸化マンガンからなる層の表面について、走査型電子顕微鏡を用いて、ＳＥＭ写真の撮影を行った。二酸化マンガンからなる層の表面のＳＥＭ写真を、図１０（Ａ）および図１０（Ｂ）に示す。２万倍の写真である図１０（Ｂ）から明らかなように、得られた二酸化マンガンからなる層は、針状のマンガン酸化物粒子が凝集することにより構成された二次粒子で形成されてなるものであることが確認された。また、得られたＳＥＭ写真を用いて、実施例１と同様にして、長さ１０μｍあたりの凸部の数、および針状のマンガン酸化物粒子のアスペクト比の測定を行った。結果を表１に示す。 Then, SEM photographs were taken on the surface of the layer made of manganese dioxide of the positive electrode obtained above using a scanning electron microscope. The SEM photograph of the surface of the layer which consists of manganese dioxide is shown to FIG. 10 (A) and FIG. 10 (B). As is clear from FIG. 10 (B), which is a 20,000-fold photograph, the obtained manganese dioxide layer is formed of secondary particles formed by agglomeration of acicular manganese oxide particles. It was confirmed that Further, using the obtained SEM photograph, the number of convex portions per 10 μm length and the aspect ratio of acicular manganese oxide particles were measured in the same manner as in Example 1. The results are shown in Table 1.
　次いで、上記にて得られた正極を用いた以外は、実施例１と同様にして、コイン電地を作製し、同様に評価を行った。充放電試験の結果得られた充放電プロファイルを図１１に、５サイクルの充放電試験における平均放電容量を表１に示す。 Next, a coin electric ground was prepared and evaluated in the same manner as in Example 1 except that the positive electrode obtained above was used. FIG. 11 shows the charge / discharge profile obtained as a result of the charge / discharge test, and Table 1 shows the average discharge capacity in the 5-cycle charge / discharge test.
《比較例１》
　基材としての炭素繊維（「ＰｙＲＯＦＩＬ ＧＤＬ」、三菱レイヨン社製、厚み０．２ｍｍ、１４ｍｍφに打ち抜いたもの）に、市販試薬特級の硫酸マンガン（ＩＩ）五水和物を０．５ｍｏｌ／ｌとなるように純水に溶解させることにより得られためっき浴を用いて、炭素繊維をアノードとし、以下の条件で、アノード定電流電解により、電気めっきを行うことで、炭素繊維の表面に二酸化マンガン（ＭｎＯ２）からなる層を形成することで、正極を得た。なお、得られた二酸化マンガンからなる層は、重量１．８ｍｇであり、重量法による膜厚で２．３２μｍに相当するものであった。
　　めっき浴：０．５Ｍ　硫酸マンガン水溶液（浴温：４０℃、ｐＨ：３．０）
　　電流印加方式：アノード定電流電解
　　アノード電流密度：５．０Ａ／ｄｍ２
　　アノード通電量：２９Ｃ（／１６ｃｍ２）
　　カソード：白金板 << Comparative Example 1 >>
Carbon fiber (“PyROFIL GDL”, manufactured by Mitsubishi Rayon Co., Ltd., punched to a thickness of 0.2 mm, 14 mmφ) as a base material, 0.5 mol / l of a commercially available reagent-grade manganese (II) sulfate pentahydrate Using a plating bath obtained by dissolving in pure water, carbon fiber is used as an anode, and electroplating is performed by anode constant current electrolysis under the following conditions, whereby manganese dioxide is deposited on the surface of the carbon fiber. A positive electrode was obtained by forming a layer made of (MnO 2 ). The obtained layer made of manganese dioxide weighed 1.8 mg and was equivalent to 2.32 μm by a gravimetric method.
Plating bath: 0.5M manganese sulfate aqueous solution (bath temperature: 40 ° C., pH: 3.0)
Current application method: Anode constant current electrolysis Anode current density: 5.0 A / dm 2
Anode energization amount: 29 C (/ 16 cm 2 )
Cathode: Platinum plate
　そして、上記にて得られた正極の二酸化マンガンからなる層の表面について、走査型電子顕微鏡を用いて、ＳＥＭ写真の撮影を行った。二酸化マンガンからなる層の表面のＳＥＭ写真を、図１２（Ａ）および図１２（Ｂ）に示す。図１２（Ａ）および図１２（Ｂ）に示すように、得られた二酸化マンガンからなる層は、凹凸構造を有しないものであった。 Then, SEM photographs were taken on the surface of the layer made of manganese dioxide of the positive electrode obtained above using a scanning electron microscope. The SEM photograph of the surface of the layer which consists of manganese dioxide is shown to FIG. 12 (A) and FIG. 12 (B). As shown in FIG. 12 (A) and FIG. 12 (B), the obtained layer made of manganese dioxide did not have an uneven structure.
　次いで、上記にて得られた正極を用いた以外は、実施例１と同様にして、コイン電地を作製し、同様に評価を行った。充放電試験の結果得られた充放電プロファイルを図１３に、５サイクルの充放電試験における平均放電容量を表１に示す。 Next, a coin electric ground was prepared and evaluated in the same manner as in Example 1 except that the positive electrode obtained above was used. FIG. 13 shows the charge / discharge profile obtained as a result of the charge / discharge test, and Table 1 shows the average discharge capacity in the 5-cycle charge / discharge test.
《比較例２》
　基材としてのＮｉめっきアルミニウム板（Ｎｉめっき厚み１．０μｍ、基材厚み０．３ｍｍ）に、市販試薬特級の塩化マンガン（ＩＩ）四水和物を０．５ｍｏｌ／ｌとなるように純水に溶解させることにより得られためっき浴を用いて、Ｎｉめっきアルミニウム板をアノードとし、以下の条件で、アノード定電流電解により、電気めっきを行うことで、Ｎｉめっきアルミニウム板の表面に二酸化マンガン（ＭｎＯ２）からなる層を形成した。
　　めっき浴：０．５Ｍ　硫酸マンガン水溶液（浴温：４０℃、ｐＨ：３．０）
　　電流印加方式：アノード定電流電解
　　アノード電流密度：０．０５Ａ／ｄｍ２
　　アノード通電量：２３０Ｃ（／１６ｃｍ２）
　　カソード：白金板 << Comparative Example 2 >>
Pure water such that a commercially available reagent-grade manganese (II) chloride tetrahydrate is 0.5 mol / l on a Ni-plated aluminum plate (Ni plating thickness 1.0 μm, substrate thickness 0.3 mm) as a substrate. By using a plating bath obtained by dissolving in a nickel plating aluminum plate as an anode, and electroplating by anode constant current electrolysis under the following conditions, manganese dioxide ( A layer made of MnO 2 ) was formed.
Plating bath: 0.5M manganese sulfate aqueous solution (bath temperature: 40 ° C., pH: 3.0)
Current application method: anode constant current electrolysis anode current density: 0.05 A / dm 2
Anode energization amount: 230 C (/ 16 cm 2 )
Cathode: Platinum plate
　次いで、二酸化マンガンからなる層を形成したＮｉめっきアルミニウム板から、二酸化マンガンからなる層を剥離させ、剥離させた二酸化マンガンからなる層を、乳鉢を用いて、数μｍ～数十μｍの粒子径に破砕する処理を行い、次いで、破砕後の二酸化マンガンをろ過した後、乾燥することで、二酸化マンガン粉末を得た。そして、得られた二酸化マンガン粉末１３３ｍｇに、導電助剤としてのケッチェンブラック９ｍｇ、バインダとしてポリフッ化ビニリデン７ｍｇを加えた後、塗布可能な粘度に調整すべくＮ－メチルピロリドン８００ｍｇを加えて正極スラリを作製し、テフロン棒（テフロンは登録商標）を用いて炭素繊維（「ＰｙＲＯＦＩＬ ＧＤＬ」、三菱レイヨン社製、厚み０．２ｍｍ）上に、乾燥後の厚みが６．５μｍとなるように塗布し、Ｎ－メチルピロリドンを乾燥により除去することにより、正極を得た。 Next, the layer made of manganese dioxide is peeled off from the Ni-plated aluminum plate on which the layer made of manganese dioxide is formed, and the peeled layer made of manganese dioxide is made into a particle diameter of several μm to several tens μm using a mortar. The process which crushes was performed, and then the manganese dioxide after the crushing was filtered and then dried to obtain a manganese dioxide powder. To 133 mg of the obtained manganese dioxide powder, 9 mg of ketjen black as a conductive additive and 7 mg of polyvinylidene fluoride as a binder were added, and then 800 mg of N-methylpyrrolidone was added to adjust the viscosity to be applicable, thereby adding a positive electrode slurry. And coated on a carbon fiber (“PyROFIL GDL”, manufactured by Mitsubishi Rayon Co., Ltd., thickness 0.2 mm) using a Teflon rod (Teflon is a registered trademark) so that the thickness after drying is 6.5 μm. N-methylpyrrolidone was removed by drying to obtain a positive electrode.
　そして、上記にて得られた正極の二酸化マンガンからなる層の表面について、走査型電子顕微鏡を用いて、ＳＥＭ写真の撮影を行った。二酸化マンガンからなる層の表面のＳＥＭ写真を、図１４（Ａ）および図１４（Ｂ）に示す。 Then, SEM photographs were taken on the surface of the layer made of manganese dioxide of the positive electrode obtained above using a scanning electron microscope. The SEM photograph of the surface of the layer which consists of manganese dioxide is shown to FIG. 14 (A) and FIG. 14 (B).
　次いで、上記にて得られた正極を１４ｍｍφに打ち抜き、１４ｍｍφに打ち抜いた正極を用いた以外は、実施例１と同様にして、コイン電地を作製し、同様に評価を行った。充放電試験の結果得られた充放電プロファイルを図１５に、５サイクルの充放電試験における平均放電容量を表１に示す。なお、上述したように、図１５および表１において、放電容量は、電極活物質層の単位重量当たりの容量を「ｍＡｈ／ｇ」で示しており、そのため、比較例２においては、放電容量に寄与しない、導電助剤としてのケッチェンブラック、およびバインダとしてポリフッ化ビニリデンの重量をも含んだ重量に対する放電容量となっている。 Next, a coin electric ground was prepared and evaluated in the same manner as in Example 1 except that the positive electrode obtained above was punched to 14 mmφ and a positive electrode punched to 14 mmφ was used. FIG. 15 shows the charge / discharge profile obtained as a result of the charge / discharge test, and Table 1 shows the average discharge capacity in the 5-cycle charge / discharge test. As described above, in FIG. 15 and Table 1, the discharge capacity indicates the capacity per unit weight of the electrode active material layer as “mAh / g”. The discharge capacity with respect to the weight including the weight of ketjen black as a conductive auxiliary agent and polyvinylidene fluoride as a binder which does not contribute.
Figure JPOXMLDOC01-appb-T000001
 　表１中において、「５サイクルの平均放電容量」は、活物質層としての二酸化マンガンからなる層の重量当たりの放電容量（すなわち、活物質層当たりの放電容量）を示している。また、表１において、「基材」は５サイクルの平均放電容量測定の際の電極の基材を示しており、比較例２においては、別の基材上に塗布法により形成した二酸化マンガンからなる層を剥離、粉砕し、これを炭素繊維上に形成したものを用いて、５サイクルの平均放電容量を測定したため、「基材」を炭素繊維としている。
Figure JPOXMLDOC01-appb-T000001
 In Table 1, “5 cycles of average discharge capacity” indicates discharge capacity per weight of a layer made of manganese dioxide as an active material layer (that is, discharge capacity per active material layer). Further, in Table 1, “base material” indicates a base material of an electrode in measuring the average discharge capacity of 5 cycles, and in Comparative Example 2, from manganese dioxide formed on another base material by a coating method. Since the average discharge capacity of 5 cycles was measured using a layer formed by peeling and pulverizing and forming this on carbon fiber, the “substrate” is made of carbon fiber.
　表１に示すように、活物質層としての二酸化マンガンからなる層を、電気めっきにより形成し、かつ、凹凸形状を有するものとした実施例１～５においては、５サイクルの平均放電容量が、いずれも高く、従来より用いられているコバルト酸リチウム正極と同等以上であり、高放電容量を実現できるものであった。
　一方、活物質層としての二酸化マンガンからなる層を、電気めっきにより形成したものの、凹凸形状を有しない比較例１、および塗布法により二酸化マンガンからなる層を形成した比較例２は、５サイクルの平均放電容量が、いずれも低くなり、放電容量が低いものであった。 As shown in Table 1, in Examples 1 to 5 in which the layer made of manganese dioxide as the active material layer was formed by electroplating and had an uneven shape, the average discharge capacity of 5 cycles was Both were high, equivalent to or better than the conventionally used lithium cobaltate positive electrode, and capable of realizing a high discharge capacity.
On the other hand, although a layer made of manganese dioxide as an active material layer was formed by electroplating, Comparative Example 1 having no uneven shape and Comparative Example 2 having a layer made of manganese dioxide by a coating method had 5 cycles. The average discharge capacity was low, and the discharge capacity was low.

Claims (8)

  1. 　非水電解液を用いた電池に用いる電極であって、
    　基材の上に、電解処理により形成されたマンガン酸化物層を有し、前記マンガン酸化物層が表面に凹凸形状を有することを特徴とする非水電解液電池用電極。     An electrode used for a battery using a non-aqueous electrolyte,
    An electrode for a nonaqueous electrolyte battery, comprising a manganese oxide layer formed by electrolytic treatment on a substrate, wherein the manganese oxide layer has an uneven shape on a surface.
  2. 　前記マンガン酸化物層が、マンガン酸化物粒子が凝集することにより構成された二次粒子で形成されており、かつ、前記二次粒子によって形成された連続した凹凸形状を有する表面を備えることを特徴とする請求項１に記載の非水電解液電池用電極。 The manganese oxide layer is formed of secondary particles formed by agglomeration of manganese oxide particles, and includes a surface having a continuous uneven shape formed by the secondary particles. The electrode for nonaqueous electrolyte batteries according to claim 1.
  3. 　前記マンガン酸化物層は、長さ１０μｍあたりに、前記二次粒子により形成された凸部を４個以上有することを特徴とする請求項２に記載の非水電解液電池用電極。 The electrode for a non-aqueous electrolyte battery according to claim 2, wherein the manganese oxide layer has four or more convex portions formed of the secondary particles per 10 µm in length.
  4. 　前記マンガン酸化物層が、針状のマンガン酸化物粒子が凝集することにより構成された二次粒子で形成されていることを特徴とする請求項１～３のいずれかに記載の非水電解液電池用電極。 The nonaqueous electrolytic solution according to any one of claims 1 to 3, wherein the manganese oxide layer is formed of secondary particles formed by aggregation of acicular manganese oxide particles. Battery electrode.
  5. 　前記針状のマンガン酸化物粒子のアスペクト比が、１：３～１：１００であることを特徴とする請求項４に記載の非水電解液電池用電極。 The electrode for a non-aqueous electrolyte battery according to claim 4, wherein an aspect ratio of the acicular manganese oxide particles is 1: 3 to 1: 100.
  6. 　前記基材が、アルミニウム、アルミニウム合金、炭素または炭素被覆アルミニウムからなる基材であることを特徴とする請求項１～５のいずれかに記載の非水電解液電池用電極。 6. The electrode for a non-aqueous electrolyte battery according to claim 1, wherein the substrate is a substrate made of aluminum, an aluminum alloy, carbon, or carbon-coated aluminum.
  7. 　前記マンガン酸化物層を構成するマンガン酸化物が、二酸化マンガンであることを特徴とする請求項１～６のいずれかに記載の非水電解液電池用電極。 The electrode for a nonaqueous electrolyte battery according to any one of claims 1 to 6, wherein the manganese oxide constituting the manganese oxide layer is manganese dioxide.
  8. 　請求項１～７のいずれかに記載の非水電解液電池用電極を備える非水電解液電池。 A non-aqueous electrolyte battery comprising the electrode for a non-aqueous electrolyte battery according to any one of claims 1 to 7.
PCT/JP2013/072995 2012-12-14 2013-08-28 Electrode for nonaqueous electrolyte battery and nonaqueous electrolyte battery WO2014091799A1 (en)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS53111429A (en) * 1977-03-09 1978-09-29 Matsushita Electric Ind Co Ltd Method of manufacturing battery and positive electrode active material thereof
JPH05266888A (en) * 1992-03-17 1993-10-15 Matsushita Electric Ind Co Ltd Alkaline battery
JPH05307964A (en) * 1992-04-30 1993-11-19 Sanyo Electric Co Ltd Non-aqueous electrolyte battery
JPH11345612A (en) * 1998-06-03 1999-12-14 Remikkusu:Kk Manufacture of positive electrode material for lithium battery

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS53111429A (en) * 1977-03-09 1978-09-29 Matsushita Electric Ind Co Ltd Method of manufacturing battery and positive electrode active material thereof
JPH05266888A (en) * 1992-03-17 1993-10-15 Matsushita Electric Ind Co Ltd Alkaline battery
JPH05307964A (en) * 1992-04-30 1993-11-19 Sanyo Electric Co Ltd Non-aqueous electrolyte battery
JPH11345612A (en) * 1998-06-03 1999-12-14 Remikkusu:Kk Manufacture of positive electrode material for lithium battery

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