JPH1186874A - Electrode for nonaqueous electrolyte secondary battery or nonaqueous electrolyte capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the binding property of an electrode current collector and an active material and to provide a superior cycle characteristic by forming the current collector with an insulating material having the volume specific resistance value of a specific value or above, and providing an insulating layer with the thickness in a specific range. SOLUTION: A current collector, having an insulating layer coated with an insulating material in advance, is used. The current collector is made of a conductive material, and it is arbitrarily selected according to its use for a positive electrode or a negative electrode respectively. A material having a volume specific resistance value of 100 Ωcm or above, preferably an organic insulating material or a polymer insulating material, is used for the insulating material. The insulating layer applied to the surface of the current collector preferably has a uniform thickness, and the average film thickness is set to 0.01-10 μm. A silane coupling agent, a titanate coupling agent, an aluminum coupling agent, a fluorine polymer, or a diene polymer can be cited for the insulating material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrode used for a battery or a capacitor, and more particularly to an electrode for a lithium secondary battery.

[0002]

2. Description of the Related Art Usually, a battery electrode is prepared by dissolving a binder for a battery (hereinafter sometimes simply referred to as a binder) in a solvent or dispersing it in a dispersion medium to form a binder composition. A battery electrode slurry (hereinafter sometimes referred to as a slurry), which is a mixture of substances, is applied to a current collector, and a solvent or a dispersion medium is removed by a method such as drying to form an active material on the current collector. It is manufactured by attaching active materials to each other. The capacity of the battery is determined by a plurality of factors such as the type and amount of the active material and the type and amount of the electrolytic solution, and the performance of the binder is also an important factor. If the binder can bind a sufficient amount of the active material to the current collector, and if the active materials cannot be bound to each other, a large capacity battery cannot be obtained. The active material falls off from the electric body, and the capacity of the battery decreases. At this time, if the binder hinders the reaction of the active material, the capacity of the battery is reduced. Therefore, the binder must not reduce the capacity. That is,
The binder has a strong binding property between the current collector and the active material and the active material, and prevents the active material from dropping from the current collector or the active materials from falling due to volume fluctuation of the active material even after repeated charge and discharge. Therefore, it is desired to improve the capacity and cycle characteristics of the battery.

[0003] By the way, a polyvinylidene fluoride-based polymer that is frequently used industrially as a binder for a lithium secondary battery is dissolved in N-methylpyrrolidone or the like to form an organic solvent-based binder composition. Thereafter, the active material is mixed to form a slurry, which is applied to a current collector and dried to form an electrode. However, when this binder is used, the binding property between the current collector and the active material is not always sufficient, and the active material is dropped off (insufficient binding force) due to the volume change of the active material due to repeated charging and discharging. There is a big problem in the binding durability (see, for example,
031 publication). This is thought to be because the polyvinylidene fluoride-based polymer surrounds the active material in a network (fibril) shape, which has a strong binding property for binding the active materials. This is considered to be due to the fact that the bonding between the active material and the active material is not sufficiently effective.
Further, latex rubber particles suspended in water are used as a binder (for example, see JP-A-5-2106).
No. 8, JP-A-5-74461, etc.), but also in this case, the binding force between the current collector and the active material may be insufficient, and sufficient performance has not yet been obtained. . As a method of enhancing the binding property between the current collector and the active material, in addition to examining the design of the binder and the active material itself, the surface of the current collector in contact with the active material layer is, for example, a polyamide or an electronic conductive auxiliary, There has been proposed a method of improving the binding property between an active material and a current collector by forming a thin binder layer by treating with an acrylic copolymer mixed with a conductive agent or the like (Japanese Patent Application Laid-Open No. Hei 6 (1994) -6380). -260164, JP-A-8-329928, JP-A-9-35707, etc.). In any of these known methods, the binding layer between the current collector surface and the active material layer is devised so that electricity easily flows between the current collector surface and the active material layer. That is, as typified by JP-A-6-260164, a method of applying a part of the current collector of the positive electrode to the surface of the current collector with a polyamide resin is to reduce internal resistance by dispersing graphite or metal powder. Polyamide resin is used. JP-A-8-329928 attempts to improve the charge / discharge cycle characteristics by forming a lower layer containing an electron conduction aid having a large particle size and forming an active material layer comprising an active material and a binder thereon. In addition, as described in JP-A-9-35707, a multilayer structure in which a binding layer made of a conductive agent having conductivity and an acrylic copolymer is formed between a current collector and an electrode active material is provided. Attempts have been made to achieve both charge-discharge cycle characteristics and binding properties. However, JP-A-6-2
As described in Japanese Patent No. 60164, the method of forming the binding layer only on a part of the current collector is such that the active material layer applied on the binding layer is further laminated, so that the thickness of the active material layer is reduced. Because there is a difference between the part with the bonding layer and the part without the binding layer,
Uniform battery performance cannot be exhibited on the electrode surface, and it is difficult to mass-produce batteries having the same performance. Also, in a method in which a conductive agent such as graphite or metal powder is dispersed and mixed into a binder used for a binder layer, if the amount of the conductive agent is small, the conductive agent in the binder layer tends to be insufficiently dispersed, and If the amount is too large to achieve its purpose, the amount of the binder used in the binder layer becomes too small, and the binder layer itself becomes difficult to bind and does not serve as the binder layer. Further, in order to firmly form a binder layer in which such a conductive agent is dispersed and mixed on a current collector, it is necessary to apply the conductive agent to a sufficient thickness in order to prevent the conductive agent from peeling off. This means that the amount of active material per battery must be reduced. And since a small amount of active material causes a significant decrease in battery performance,
This is by no means the preferred method. As described above, the conventional method using the binding layer has many problems because it is a method developed based on the idea that sufficient electricity must flow between the current collector and the active material layer. Was. As described above, at present, a nonaqueous electrolyte secondary battery having excellent binding properties to the electrode current collector, excellent holding power of the electrode active material, and excellent cycle characteristics has not yet been obtained.

[0004]

SUMMARY OF THE INVENTION Based on such prior art, the present invention provides a non-aqueous electrolyte secondary battery which enhances the binding between a current collector and an active material and exhibits good cycle characteristics. As a result of intensive studies to obtain a current collector, the current collector surface was coated with an insulating material, and the binding property between the electrode current collector and the active material was unexpectedly improved. The inventors have found that not only the battery can be improved but also a battery having excellent cycle characteristics can be obtained, and the present invention has been completed.

[0005]

Thus, according to the present invention, there is provided an electrode for a battery or capacitor obtained by applying a slurry containing an active material and a binder to a current collector and drying the slurry. Volume resistivity 100Ωcm
An electrode for a battery or a capacitor is provided which uses an insulating layer having a thickness of 0.01 to 10 μm made of the above insulating material, and a non-aqueous electrolyte secondary battery using these electrodes. And a non-aqueous electrolyte capacitor.

[0006]

DETAILED DESCRIPTION OF THE INVENTION In the present invention,
A feature is that a current collector having a layer covered with an insulating substance (hereinafter, simply referred to as an insulating layer) is used. (Current Collector) The current collector used in the present invention is not particularly limited as long as it is made of a conductive material.
Metallic materials such as copper, aluminum, and nickel (metal foils and the like) can be arbitrarily selected and used according to the respective applications of the positive electrode and the negative electrode. Although the shape is not particularly limited, for example, when it is used for a small lithium ion secondary battery or the like, a sheet having a thickness of about 0.001 to 0.5 mm is usually used. (Insulating layer) In the present invention, the insulating substance is a substance having a volume resistivity of 100 Ωcm or more, preferably 1000 Ωcm or more, more preferably 10,000 Ωcm or more, and an organic insulating material (hereinafter referred to as an insulating organic substance). In some cases) and a polymer-based insulating material (hereinafter, sometimes referred to as an insulating polymer).

Specific examples of the organic insulating material used in the present invention include silane coupling agents such as dimethyldiethoxysilane, dimethyldichlorosilane, and 3- (N, N-diglycidyl) aminopropyltrimethoxysilane; Isopropyl triisostearoyl titanate,
Titanate-based coupling agents such as isopropyltrioctanoyl titanate; aluminum-based coupling agents such as acetoalkoxyaluminum diisopropylate; and the like. Specific examples of the polymer insulating material include polyvinylidene fluoride, Fluorinated polymers such as polytetralofluoroethylene and vinylidene fluoride-6-propylene copolymer; polybutadiene, isoprene-isobutylene copolymer, natural rubber, styrene-butadiene copolymer, butadiene-acrylonitrile copolymer, Diene polymers such as ethylene-propylene copolymer and ethylene-propylene-diene copolymer; polyethylene, polypropylene, ethylene-vinyl acetate copolymer, ethylene ionomer, polyvinyl alcohol, ethylene-vinyl Olefin polymers such as alcohol copolymers, chlorinated polyethylene, and chlorosulfonated polyethylene; styrene polymers such as styrene-ethylene-butadiene copolymer, styrene-butadiene-propylene copolymer, and styrene-isoprene copolymer Acrylate polymers such as polymethyl methacrylate, polymethyl acrylate, polyethyl acrylate, polybutyl acrylate, and acrylate-acrylonitrile copolymer; polyamides such as polyamide 6, polyamide 66, polyamide 11, polyamide 12, aromatic polyamide and polyimide Acid or polyimide acid polymer; ester condensed polymer such as polyethylene terephthalate and polybutylene terephthalate; hydroxyethyl cellulose, hydroxypropyl cellulose And the like, and the like; carboxyl methyl, ethyl cellulose cellulose polymers like.

Among these, fluorine-based polymers, diene-based polymers, styrene-based polymers, acrylate-based polymers, and cellulose-based polymers are particularly preferred examples. Even if these insulating organic substances and insulating polymers are used alone or as a blend of two or more kinds, the purpose can be sufficiently achieved.

As a method of coating the surface of the current collector with an insulating layer of an insulating material represented by the above-mentioned insulating organic material or insulating polymer, the insulating material is directly heated and dissolved to form a liquid. Can be applied and coated on
In general, it is preferable to dissolve or disperse an insulating substance at a predetermined concentration in an organic or inorganic liquid medium, apply and dry it on the current collector surface, and apply an insulating layer on the current collector surface. Examples of the coating method include an extrusion coater, a reverse roller, a doctor blade, a dipping method, a casting method, and the like, but other general coating methods may be employed. When a multilayer film is formed, the above methods can be appropriately combined.
In addition to the method of heating and dissolving and the method of using a liquid medium, a method of forming an insulating layer film in advance by a manufacturing method such as extrusion molding, injection molding, inflation molding, and then bonding the same to a current collector, or a method of powdering an insulating substance. It is also possible to adopt a method of powder coating in a dry state or a method of a dry process such as plasma or vacuum deposition. In general, the temperature at which the insulating substance-containing liquid is applied to the current collector can be arbitrarily set depending on the application method, but the insulating substance is dissolved or dispersed in an organic or inorganic liquid medium and applied to the current collector. In the method of applying the insulating layer by drying, the coating is usually performed at a temperature lower than the boiling point of the solvent and at a temperature at which the solvent volatilizes (for example, at a temperature about 5 to 100 ° C. lower than the boiling point). It is desirable because there is no unevenness.

[0010] The drying method after the application of the insulating material (particularly when an organic or inorganic liquid medium is used) includes a method of drying by applying hot air, a method of vacuum drying, and a method of standing in a high temperature and low humidity environment. No. The drying temperature can be arbitrarily set depending on the drying method, but a temperature lower than the boiling point of the organic or inorganic liquid medium or the insulating substance itself, usually 76
When the boiling point at 0 mmHg is set to 10 ° C. or more and 400 ° C. or less, preferably 15 ° C. or more and 300 ° C. or less, more preferably 20 ° C. or more and 250 ° C. or less, it is desirable because there is no uneven coating.

The organic or inorganic liquid medium used for dissolving or dispersing the insulating material is not particularly limited, but is preferably 760 mmHg, which is compatible with the insulating organic material or the insulating polymer, at room temperature. Liquid boiling point 30-35
Organic compound at 0 ° C. The liquid medium can be appropriately selected depending on the application and drying temperatures.

Specific examples of the liquid medium used in the present invention include water, hydrocarbon compounds, nitrogen-containing organic compounds, oxygen-containing organic compounds, chlorine-containing organic compounds, sulfur-containing organic compounds, and the like. And more specific preferred examples of the organic liquid material include (1) hydrocarbon compounds such as aromatic hydrocarbon compounds such as benzene, toluene, and xylene; n-butane, n-pentane , N
-Hexane, n-heptane, n-octane, isooctane, cyclopentane, cyclohexane, methylcyclohexane, ethylcyclohexane, nonane, decane, decalin, dodecane, gasoline, and saturated hydrocarbon organic compounds such as industrial gasoline; (2) Examples of the nitrogen-containing organic compound include nitroethane, 1-nitropropane, 2-nitropropane, acetonitrile, triethylamine, cyclohexylamine, pyridine, monoethanolamine, diethanolamine, forforin, N, N
And nitrogen-containing organic compounds such as -dimethylformamide and N-methylpyrrolidone. (3) Examples of the oxygen-containing organic compound include methanol, ethanol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, secondary butyl alcohol, amyl alcohol, isoamyl alcohol, methyl isobutyl carbinol, and 2-ethyl. Butanol, 2-
Compounds having a hydroxyl group such as ethylhexanol, cyclohexanol, furfuryl alcohol, tetrahydrofurfuryl alcohol, ethylene glycol, hexylene glycol, glycerin; propyl ether, isopropyl ether, butyl ether, isobutyl ether, n-amyl ether, isoamyl ether, Aliphatic saturated ethers such as methyl butyl ether, methyl isobutyl ether, methyl n-amyl ether, methyl isoamyl ether, ethyl propyl ether, ethyl isopropyl ether, ethyl butyl ether, ethyl isobutyl ether, ethyl n-amyl ether, and ethyl isoamyl ether; Aliphatic unsaturated ethers such as allyl ether and ethyl allyl ether; anisole, phenene Lumpur, phenyl ether,
Aromatic ethers such as benzyl ether; cyclic ethers such as tetrahydrofuran, tetrahydropyran and dioxane; ethylene glycol monomethyl ether;
Ethylene glycols such as ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, and diethylene glycol monobutyl ether; organic acids such as formic acid, acetic acid, acetic anhydride, and butyric acid; butyl formate, amyl formate, and propyl acetate , Isopropyl acetate, butyl acetate, sec-butyl acetate,
Amyl acetate, isoamyl acetate, 2-ethylhexyl acetate, cyclohexyl acetate, butylcyclohexyl acetate,
Organic acid esters such as ethyl propionate, butyl propionate, amyl propionate, butyl butyrate, diethyl carbonate, diethyl oxalate, methyl lactate, ethyl lactate, butyl lactate and triethyl phosphate; acetone, ethyl ketone, propyl ketone, butyl ketone; Ketones such as methyl isopropyl ketone, methyl isobutyl ketone, methyl isobutyl ketone, diisobutyl ketone, acetylacetone, diacetone alcohol, cyclohexanone, cyclopentanone, methylcyclohexanone, cycloheptanone; and others such as 1,4-dioxane, isophorone, furfural And oxygen-containing organic compounds of the formula (1).
(4) Examples of the chlorine-containing organic compound include chlorine-substituted hydrocarbons such as tetrachloroethane, trichloroethylene, perchloroethylene, dichloropropane, amyl chloride, dichloropentane, and chlorobenzene.
(5) Examples of the sulfur-containing organic compound include thiophene, sulfolane, dimethyl sulfoxide and the like. Among these, an organic solvent having a boiling point at 760 mmHg of 60 to 200 ° C. is preferable.

The insulating layer applied to the surface of the current collector by the method of the present invention preferably has a uniform thickness, and has an average thickness of 0.01 μm or more and 10 μm or less, preferably 0.1 μm or less. 05 μm or more and 7 μm or less, more preferably 0.1 μm or less.
It is 1 μm or more and 5 μm or less. Here, if the average thickness of the insulating layer is too large, the binding property is good, but the charge / discharge cycle characteristics are unfavorably deteriorated. On the other hand, if the average thickness of the insulating layer is too small, the binding property deteriorates, and it is impossible to cope with repeated charge and discharge. When the film thickness is in the above-described range, a good balance between the binding property and the charge / discharge cycle characteristics can be obtained. As will be described later, as the binder to be mixed with the active material layer, a conventionally known binder can be used. However, even if the binder is not present, the active material is retained on the current collector. Is also possible.

(Active Material) The negative electrode active material used in the present invention may be any material capable of occluding and releasing lithium. Carbonaceous materials such as pyrolytic carbons, cokes,
(Petroleum coke, pitch coke, coal coke, needle coke, etc.), carbon black (acetylene black, etc.), glassy carbon, organic polymer material sintered body (organic polymer material is inert at an appropriate temperature of 500 ° C. or more. Fired in a gas stream or in a vacuum), graphites (natural graphite, artificial graphite, fibrous graphite, spherical graphite, etc.), glassy carbons,
Polyacene-based carbon and the like are preferable, and in addition, an intermetallic compound, LixMyNz (where Li represents a lithium atom, M represents a metal, preferably a boron atom, a transition metal,
More preferably, Mn, Fe, Co, Sn, Al, Ti,
It represents at least one selected from W, Si, Cu, V, Cr and Ni, and N represents a nitrogen atom. X, y
And z are respectively 7.0 ≧ x ≧ 1.0, 4 ≧ y ≧ 0,
A lithium nitride metal compound represented by the formula: 5 ≧ z ≧ 0.5, SnBxPyOz (provided that 0.
Examples thereof include metal oxides such as 1 <x <1.0, 0.1 <y <1.0, and 2 <z <4), and conductive polymers such as polyacetylene and polypyrrole.

As the positive electrode active material used in the present invention, any material can be used as long as it can be used for the positive electrode of a lithium secondary battery, but a lithium-containing metal composite oxide is preferable. Particularly preferred cathode active material is LixMO ₂ (where M represents at least one transition metal, preferably at least one of Co, Mn or Ni, and 1.10>x> 0.05), or L
ixM ₂ O ₄ (where M represents one or more transition metals, preferably Mn, and 1.10>x> 0.05), for example, LiCoO ₂ , LiNi
O ₂ , LixNiyCo (1-y) O ₂ (provided that 1.10
>X> 0.05, 1>y> 0), and a composite oxide represented by LiMn ₂ O ₄ .

(Binder, Binder Composition, Slurry) In the present invention, a binder can be used for binding active materials and binding the active material to the current collector. A binder is prepared by dissolving or dispersing the binder in water or an organic liquid material to prepare a binder composition, and mixing the active material and, if necessary, additives and the like to form a slurry. It is desirable to apply and dry the coated current collector to produce an electrode. As the binder, any binder may be used as long as it is generally used.For example, fluorine-based rubber, diene-based rubber, styrene-based rubber, nitrile rubber, acrylic rubber, neoprene,
Butyl rubber, thiocol, polyurethane rubber; various rubbers such as block copolymers produced using diene and styrene monomers; fluorinated polymers such as polytetrafluoroethylene and polyvinylidene fluoride; polyethylene, polypropylene and polystyrene Polyolefin resins such as polymethacrylic acid; nitrile resins such as polyacrylonitrile; resins such as other polyester resins, phenolic resins, polyvinyl acetate resins, polyvinyl alcohol resins, and epoxy resins; Can be. Specific examples of more preferable binders include fluorine-based rubber such as fluorine-containing rubber; diene-based rubber obtained by using a diene such as butadiene polymer and isoprene polymer; styrene-1,3-
Butadiene copolymer, styrene-isoprene copolymer,
Styrene-based rubbers obtained using styrenes such as styrene-1,3-butadiene-isoprene copolymer;
3-butadiene-acrylonitrile copolymer, 1,3-
Butadiene-isoprene-acrylonitrile copolymer,
Styrene-acrylonitrile-1,3-butadiene copolymer, styrene-acrylonitrile-1,3-butadiene-methyl methacrylate copolymer, styrene-acrylonitrile-1,3-butadiene-itaconic acid copolymer,
Styrene-acrylonitrile-1,3-butadiene-methyl methacrylate-fumaric acid copolymer, styrene-1,
Nitrile group-containing rubber containing nitrile group such as 3-butadiene-itaconic acid-methyl methacrylate-acrylonitrile copolymer; rubber having a saturated main chain such as acrylic rubber, copolymer rubber obtained by using ethylene and propylene Styrene-based block copolymers such as polystyrene-polybutadiene block copolymers; polyvinylidene fluoride, polytetrafluoroethylene, tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoroethylene-perfluoroalkylvinyl ether copolymer, polystyrene Fluorinated polymers such as chlorotrifluoroethylene, polyvinyl fluoride, ethylene-chlorotrifluoroethylene copolymer and the like; polyalkylene resins such as polyethylene and polypropylene; polystyrene resins;
An acrylic resin such as polymethacrylic acid may be used.
These binders are mixed with the active material according to a standard method,
It is bound to the current collector via the insulating layer according to the present invention.

The organic liquid substance for dissolving or dispersing the above-mentioned binder is preferably a substance that is liquid at room temperature (20 ° C.) (hereinafter, may be simply referred to as a liquid substance). Any substance that can be dissolved or dispersed may be used. Specific examples include alcohols such as methanol, ethanol, propanol, isopropanol, butanol, isobutanol, s-butanol, t-butanol, pentanol, isopentanol, and hexanol. Ketones such as acetone, methyl ethyl ketone, methyl propyl ketone, ethyl propyl ketone, cyclopentanone, cyclohexanone and cycloheptanone; methyl ethyl ether;
Diethyl ether, dipropyl ether, diisopropyl ether, dibutyl ether, diisobutyl ether, di-n-amyl ether, diisoamyl ether, methyl propyl ether, methyl isopropyl ether,
Ethers such as methyl butyl ether, ethyl propyl ether, ethyl isobutyl ether, ethyl n-amyl ether, ethyl isoamyl ether, and tetrahydrofuran; lactones such as γ-butyrolactone and δ-butyrolactone; lactams such as β-lactam; cyclopentane; Cyclic aliphatics such as cyclohexane and cycloheptane; benzene, toluene, o-xylene, m-
Aromatic hydrocarbons such as xylene, p-xylene, ethylbenzene, propylbenzene, isopropylbenzene, butylbenzene, isobutylbenzene, n-amylbenzene; aliphatic hydrocarbons such as heptane, octane, nonane, decane; dimethyl Linear and cyclic amides such as formamide and N-methylpyrrolidone; esters such as methyl lactate, ethyl lactate, propyl lactate, butyl lactate, and methyl benzoate; You.

The ratio of the binder and the active material is usually 1 to 1000 times the weight of the binder with respect to the binder.
Preferably 2-500 times, more preferably 3-300
And more preferably 5 to 200 times. The amount of the organic or inorganic liquid material used when the active material and the binder are mixed to form a slurry is not particularly limited, and is arbitrary depending on the ease of application to the current collector and the thickness of the coated film. Ratio.

(Additives) If necessary, various additives such as a viscosity modifier, a binding aid, and a conductive material (conductive carbon such as acetylene black) can be added to the slurry. As the additive, those arbitrarily selected can be used, for example, carboxymethylcellulose, carboxyethylcellulose, ethylcellulose, hydroxymethylcellulose, hydroxypropylcellulose,
Cellulose derivatives such as carboxyethyl methylcellulose (and salts thereof such as ammonium salts and alkali metal salts), polyethylene oxide, ethylene glycol, polycarboxylic acid, polyvinyl alcohol, ethylene-vinyl alcohol copolymer, and parts of polyvinyl acetate Water-soluble polymers such as saponified compounds are preferred additives for improving battery performance.

Further, other additives, for example, a rubber used for modifying a cellulosic compound can be added for the purpose of being used in combination with the binder of the present invention. The amount of the additive is not particularly limited, but is preferably 0.01 to 500 parts by weight, more preferably 0.1 to 300 parts by weight, based on 100 parts by weight of the binder.

(Electrode) The electrode of the present invention is formed on a current collector by applying and drying the above slurry on a current collector provided with an insulating layer made of an insulating material by the above-mentioned method in a conventional manner. The active material is fixed in the matrix thus obtained.

The method of applying the slurry to the current collector is not particularly limited. For example, it is applied by a blade method, a reverse roll method, a direct roll method, a knife method, a dipping method, or the like. The amount to be applied is not particularly limited, but the thickness of the active material layer formed after drying and removing the solvent or the dispersion medium is usually 0.005 to 5 mm, preferably 0.05 to 2 m.
m.

(Electrolyte) A non-aqueous electrolyte battery and a non-aqueous electrolyte capacitor produced by using the electrode of the present invention obtained by the method of the present invention and an electrolytic solution are produced. Here, the electrolytic solution is composed of an electrolyte and a liquid that dissolves the electrolyte. The liquid for dissolving the electrolyte is not particularly limited as long as it is commonly used, but carbonates such as propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, and diethyl carbonate; lactones such as γ-butyl lactone; Ethers such as trimethoxymethane, 1,2-dimethoxyethane, diethyl ether, 2-ethoxyethane, tetrahydrofuran, 2-methyltetrahydrofuran; sulfoxides such as dimethyl sulfoxide;
Oxolanes such as 1,3-dioxolan, 4-methyl-1,3-dioxolan; nitrogen-containing compounds such as acetonitrile and nitromethane; methyl formate, methyl acetate, ethyl acetate, butyl acetate, methyl propionate, ethyl propionate and the like. Organic acid esters; inorganic acid esters such as phosphoric acid triesters and diester carbonates such as dimethyl carbonate, diethyl carbonate and dipropyl carbonate; diglymes;
A single solvent or a mixture of two or more solvents such as triglymes; sulfolane; oxazolidinones such as 3-methyl-2-oxazolidinone; sultones such as 1,3-propane sultone, 1,4-butane sultone, and naphtha sultone;

As the electrolyte, any of conventionally known lithium salts can be used, and LiCLo ₄ , LiBF ₆ , LiPF ₆ ,
LiCF ₃ SO ₃ , LiCF ₃ CO ₂ , LiAsF ₆ , Li
SbF ₆ , LiB ₁₀ Cl ₁₀ , LiAlCl ₄ , LiCl,
LiBr, LiB (C ₂ H ₅ ) ₄ , CF3SO3Li, C
_{H3SO3Li, LiCF 3 SO 3, LiC} 4 F 9 S0 3,
Li (CF ₃ SO ₂ ) ₂ N, lithium lower fatty acid carboxylate, and the like. (Battery, Condenser) The non-aqueous electrolyte secondary battery of the present invention uses the above electrode for at least one of a positive electrode and a negative electrode. The battery may be either a battery using an aqueous electrolyte or a battery using a non-aqueous electrolyte, but can obtain particularly excellent battery performance when used as an electrode of a battery using a non-aqueous electrolyte. it can. Examples of the battery using a non-aqueous electrolyte include lithium-based batteries such as a lithium primary battery, a lithium metal secondary battery, a lithium ion secondary battery, a lithium polymer secondary battery, and a lithium ion polymer secondary battery. In the non-aqueous electrolyte capacitor of the present invention, two electrodes (including a current collector) usually placed via a separator are inserted into a coin-shaped metal container or wound and wound into a cylindrical or square shape. After being inserted into a metal container and filled with an electrolyte, a sealing plate, an insulating gasket,
This basic cell is used alone or in combination of two or more. The sealant of the present invention is provided between the insulating gasket and the metal container, and / or
Or, by providing the sealing agent layer of the present invention between the insulating gasket and the sealing plate serving as a sealing body, it is possible to prevent leakage of the electrolytic solution filled in the metal container and entry of moisture from the outside into the metal container. be able to. In the non-aqueous electrolyte capacitor of the present invention, a non-polar one using a polarizable electrode and a polarizable electrode for one electrode and a non-polarizable electrode for the other are used for the two electrodes. And polar ones. A preferred capacitor of the present invention is an electric double layer capacitor in which the electrolytic solution is an organic electrolytic solution, and its production method may be in accordance with a conventional method.

[0025]

According to the present invention, the binding property between the current collector and the active material is high, and the electrode active material does not peel off from the current collector even when charge and discharge are repeated, and a good charge is obtained. A non-aqueous electrolyte secondary battery and a non-aqueous electrolyte capacitor exhibiting discharge cycle characteristics can be obtained.

[0026]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples.

(Evaluation of Battery Characteristics) A lithium ion secondary battery was prepared in the following procedure, and its cycle characteristics were measured. Unless otherwise specified, the positive electrode had a thickness of about 20 μm in which the surface in contact with the active material layer was surface-treated with an insulating material by a method described later.
The slurry was applied to a μm aluminum foil current collector, dried, and compressed to prepare a slurry. Unless otherwise specified, the negative electrode was prepared by applying a slurry to a copper foil current collector having a thickness of about 10 μm, which had been surface-treated with an insulating material, dried, and compressed by the method described below.

The above positive electrode and negative electrode were each 15 m in diameter.
m, and a separator made of a circular polypropylene porous membrane with a diameter of 18 mm and a thickness of 25 μm is interposed, the active materials are opposed to each other, and the aluminum foil of the positive electrode is placed in contact with the bottom surface of the outer container. A stainless steel coin-type outer container with a spring (expanded metal) placed on the copper foil of the negative electrode and a polypropylene packing installed
(Diameter 20mm, height 1.8mm, stainless steel thickness 0.
25 mm). An electrolyte in which LiPF ₆ was dissolved at a concentration of 1 mol / liter as an electrolyte was injected into a solvent in which ethylene carbonate and diethyl carbonate were mixed at a volume ratio of 1: 1 so that no air remained. A stainless steel cap with a thickness of 0.2 mm is put on and fixed to the outer container via a polypropylene packing, and the battery can is sealed to have a diameter of 20 mm and a thickness of about 2 mm.
20 coin cells were manufactured for each condition.

(Thickness of Insulating Layer) The thickness of the insulating layer was measured by using a contact type micrometer by using a contact type micrometer.
The locations were measured and their average values were taken. (Binding property) The electrode was evaluated for binding property between the current collector and the active material layer by a grid test specified in JIS K5400. The evaluation is a relative evaluation of 10 levels, and the higher the score, the better the binding property.

(Charge / discharge capacity retention rate) The battery performance was determined by using a constant current method (current density of 0.1 mA / c) for each of 20 cells.
The battery was charged to 4.0 V at m ² ) and discharged and discharged to 3.0 V, and the electric capacity was measured. The average value of 20 cells was measured and the ratio (%) of the electric capacity at the end of 50 cycles to the electric capacity at the end of 5 cycles was defined as the capacity retention.

(Examples 1-13, Comparative Example 1) The insulating substances shown in Table 1 were dissolved in toluene or N-methylpyrrolidone, respectively, to obtain 1% by weight solutions. This solution was applied to the surface of the aluminum foil as the positive electrode current collector and the surface of the copper foil as the negative electrode current collector which were in contact with the active material layer by a doctor plate method, and then dried with a commercial drier at 1000 W for about 2 minutes to remove solvent odor. After disappearing, 5mmH
g, and dried under reduced pressure at 80 ° C. for 2 hours. Table 1 shows the thickness of the insulating layer. Further, the volume resistivity value of each insulating substance used here is determined by a resistor “R-
8340 ", all of which were 1000
Ωcm or more.

[0032]

[Table 1]

Next, the positive electrode slurry and the negative electrode slurry were mixed in a ball mill at the following compounding amounts to produce the slurry. [Positive electrode] LiCoO ₂ (specific surface area: 0.5 m ² / g) 6
0 parts by weight, carbon (specific surface area: 100 m ² / g) 5
Parts by weight, 5 parts by weight of polyvinylidene fluoride (binder), 40 parts by weight of N-methyl-2-pyrrolidone [Negative electrode] 60 parts by weight of high-purity graphite (specific surface area 5 m ² / g), 5 parts by weight of polyvinylidene fluoride (binder) ,
N-methyl-2-pyrrolidone 45 parts by weight

The positive and negative electrode slurries are applied to a current collector whose surface is treated with an insulating material, and dried.
After forming an electrode with a thickness of about 100 μm for both the negative electrode, the binding property between the electrode and the current collector was evaluated. In addition, a lithium ion secondary battery was manufactured by the above method, and the charge / discharge capacity retention rate was measured. Table 2 shows the results of the evaluation of the binding property and the charge / discharge capacity retention rate. Comparative Example 1 is a result of using both the positive electrode and the negative electrode without any treatment for providing an insulating layer on the current collector surface.

[0035]

[Table 2]

Table 2 clearly shows that the performance of the electrode provided with an insulating layer on the surface of the current collector is significantly improved in the binding property and the charge / discharge capacity retention ratio as compared with the untreated product.

(Examples 14-21) A battery was prepared in the same manner as in Examples 1 to 13 except that the current collector coated with the insulating layer manufactured in Examples 1 to 13 was used for only one of the positive electrode and the negative electrode. Was prepared, and the binding property and the charge / discharge capacity retention rate were evaluated. The results are shown in Table 3. From these results, it was confirmed that the charge / discharge capacity retention of the electrode manufactured by the method of the present invention was clearly superior to the result of Comparative Example 1.

[0038]

[Table 3]

(Examples 22 to 25) Electrodes were produced in the same manner as in Examples 3, 5, 9 and 10 except that polyvinylidene fluoride as a binder was not used as a component in the slurry. Table 4 shows the results obtained by measuring the binding property and the charge / discharge capacity retention ratio of the batteries manufactured using the batteries.

[0040]

[Table 4]

As is evident from the results shown in Table 4, the electrode manufactured by the method of the present invention can sufficiently maintain battery performance even without a binder.

(Examples 26-31, Comparative Example 2-7) An electrode in which the thickness of the insulating layer on the surface of the current collector was changed was manufactured.
The charge / discharge capacity retention was measured in the same manner as described above.

[0043]

[Table 5]

(Comparative Examples 8 to 10) A methyl acrylate-styrene copolymer (methyl acrylate / styrene (reaction charge molar ratio) = 5/5) on the current collector surface and 100 parts by weight of the copolymer 10 parts by weight, 50 parts by weight, 100 parts by weight
A positive electrode and a negative electrode were prepared in the same manner as in Example 1 except that a mixture with parts by weight of graphite carbon (used as a conductive agent / average particle size of 1.5 μm) (both volume resistivity was less than 100 Ωcm) was used. A negative electrode and a positive electrode were manufactured by coating the current collector with a conductive layer having a volume resistivity of less than 100 Ωcm, and the binding property and the charge / discharge capacity retention were measured using the negative and positive electrodes. Table 6 shows the results.

[0045]

[Table 6]

(Comparative Examples 11 to 12) Average Particle Size 1.5 μm
Average particle size 5.5μ instead of graphite carbon
A negative electrode was manufactured in the same manner as in Comparative Example 10 except that graphite carbon of m and copper powder having an average particle size of 0.5 μm were used. The positive electrode was used in Comparative Example 10 except that the positive electrode of Example 1 was used. The binding property and the charge / discharge capacity retention were measured in the same manner as in the negative electrode. Table 7 shows the results.

[0047]

[Table 7]

From these results, it can be seen that if an electrode is used with a current collector having a layer to which a conductive agent is added, sufficient binding properties and charge / discharge cycle characteristics cannot be obtained.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI H01M 10/40 H01G 9/00 301F

Claims (4)

[Claims] An electrode for a battery or a capacitor obtained by applying and drying a slurry containing an active material and a binder to a current collector, wherein the current collector has a volume resistivity of 1
Thickness of 0.01 to 1 made of an insulating material of 00 Ωcm or more
An electrode for a non-aqueous electrolyte battery or a non-aqueous electrolyte capacitor, characterized by using one having an insulating layer of 0 μm. 2. The insulating material is a silane coupling agent, a titanate coupling agent, an aluminum coupling agent, a fluorine polymer, a diene polymer, an olefin polymer, a styrene polymer, an acrylate polymer. 2. The material according to claim 1, wherein the material is at least one substance selected from the group consisting of a polymer, a polyamic acid polymer, a polyimide acid polymer, an ester condensation polymer, and a cellulose polymer. Electrodes for non-aqueous electrolyte batteries or non-aqueous electrolyte capacitors. 3. A non-aqueous electrolyte secondary battery using the electrode according to claim 1. 4. A non-aqueous electrolyte capacitor using the electrode according to claim 1.