JPWO2009145225A1 - Secondary battery, method for producing the same, and ink for electrode formation - Google Patents

Abstract

The present invention is a secondary battery comprising a positive electrode and a negative electrode, wherein a polymer radical material as an electrode active material and a conductivity-imparting agent are provided on a conductive substrate of at least one of the positive electrode and the negative electrode. A secondary battery is provided, wherein the polymer radical material has a mean particle size in the range of 2 μm to 25 μm.

Description

  The present invention relates to a secondary battery using a polymer radical material as an electrode active material, a method for manufacturing the same, and an electrode forming ink used for manufacturing the secondary battery.

  In recent years, with the development of communication systems, portable electronic devices such as notebook computers and mobile phones have rapidly spread. While portable electronic devices are becoming highly functional, diversification of functions and shapes is also progressing. Therefore, various demands such as downsizing, weight reduction, high energy density, and high output density are increasing for the battery as the power source.

  As a battery having a high energy density, lithium ion batteries have been widely used since the 1990s. This lithium ion battery uses a lithium-containing transition metal oxide such as lithium manganate or lithium cobaltate as an electrode active material and carbon as a negative electrode. Insertion / desorption of lithium ions into the electrode active material is possible. Charging / discharging is performed using a separation reaction. Lithium ion batteries have a large energy density and are excellent in cycle characteristics, and thus are used in various electronic devices such as mobile phones. On the other hand, there is a drawback that it is difficult to obtain a large output, and it takes a long time for charging.

  An electric double layer capacitor is known as an electricity storage device capable of obtaining a large output. Since this electric double layer capacitor can discharge a large current at a time, it is possible to obtain a large output. However, since the energy density is very small and downsizing is difficult, it is not suitable as a power source for many portable electronic devices.

  In order to obtain a lightweight electrode material, a battery using a sulfur compound or an organic compound as an electrode active material has been developed. For example, Patent Document 1 proposes a battery using an organic compound having a disulfide bond as a positive electrode. The electrochemical redox reaction accompanied by the formation and dissociation of disulfide bonds is used as the principle of the battery. Since this battery is composed of an electrode material mainly composed of an element having a small specific gravity such as sulfur or carbon, it has a certain effect in terms of a high-capacity battery having a high energy density. However, due to the low efficiency with which the dissociated bonds are recombined and the diffusion of the electrode active material into the electrolyte, there are drawbacks in that the capacity tends to decrease with repeated charge / discharge cycles.

  In addition, as a battery using an organic compound, a battery using a conductive polymer as an electrode active material has been proposed. It is a battery based on the principle of doping and dedoping of electrolyte ions to a conductive polymer. Here, the dope reaction is a reaction in which a counter ion is doped into a charged radical generated by oxidation or reduction of a conductive polymer. Patent Document 2 discloses a battery using a conductive polymer as a positive electrode or negative electrode material. This battery was composed only of elements having a small specific gravity such as carbon and nitrogen, and was expected as a high capacity battery. However, conductive polymers have the property that charged radicals generated by redox are delocalized over a wide range of π-electron conjugated systems and interact with each other, resulting in electrostatic repulsion and radical disappearance. . This limits the dope concentration, i.e. limits the capacity of the battery. For example, it has been reported that the doping rate of a battery using polyaniline as a positive electrode is 50% or less, and 7% in the case of polyacetylene. A battery using a conductive polymer as an electrode material has a certain effect in terms of weight reduction, but a battery having a large energy density has not been obtained.

  A non-aqueous electrolyte capacitor using a conductive polymer as an electrode material has also been proposed (see Patent Document 3). In this non-aqueous electrolyte capacitor, a large output can be obtained and the energy density is higher than that of a conventional electric double layer capacitor. However, like the battery using a conductive polymer as an electrode active material, the generated dope concentration is limited and the energy density is small.

  Patent Document 4 discloses a secondary battery in which at least one active material of a positive electrode and a negative electrode contains a radical material, and Patent Documents 5 and 6 contain a nitroxyl polymer material in the positive electrode. An electricity storage device has been proposed. These power storage devices such as secondary batteries can charge and discharge with a large current because the electrode reaction of the electrode active material (radical compound) itself is fast, and therefore high output is obtained.

  However, the radical compound constituting the secondary battery or the positive electrode of the electricity storage device proposed in Patent Documents 4 to 6 is an aliphatic organic compound, and its own conductivity is extremely low. Therefore, in order to use and charge and discharge as an electrode active material, it is necessary to add a conductive material (conductivity imparting agent) so that the electrical resistance of the electrode can be reduced and the radical compound and electrons can be efficiently transferred. . Carbon materials such as carbon fiber and carbon black have been used for the conductivity-imparting agent in that it has a relatively large surface area and is easily mixed with a polymer radical material. However, when these are used, there is a problem that the ratio of radical sites that cannot participate in charge / discharge among the polymer radical materials is relatively large, and the battery capacity is small.

Japanese Patent No. 2715778 U.S. Pat. No. 4,442,187 JP 2000-315527 A Japanese Patent No. 3687736 JP 2002-304996 A JP 2007-165054 A

  An object of the present invention relates to a secondary battery using an electrode having a conductivity-imparting agent and a polymer radical material, and a new secondary battery having a high battery capacity by improving the ratio of radical sites involved in charge / discharge and its An object of the present invention is to provide a manufacturing method and an electrode forming ink used for manufacturing the secondary battery.

  As a result of intensive studies, the inventors of the present invention formed a dispersion layer formed by dispersing a conductivity imparting agent in a polymer radical material having a specific average particle diameter on a conductive substrate in the step of forming an electrode. As a result, the inventors have found that the proportion of radical sites that cannot participate in charge / discharge can be reduced, and have arrived at the present invention. In addition, in this invention, an average particle diameter represents the cumulative average diameter (50% diameter) in a volume.

That is, the present invention firstly
A secondary battery comprising a positive electrode and a negative electrode,
On the conductive substrate of at least one of the positive electrode and the negative electrode, a mixture containing a polymer radical material as an electrode active material and a conductivity-imparting agent is applied,
Provided is a secondary battery wherein the polymer radical material has an average particle size in the range of 2 μm to 25 μm.

The present invention secondly,
Dispersing a polymer radical material as an electrode active material in a medium in which the polymer radical material is not substantially dissolved or swollen to obtain a dispersion;
Mixing the dispersion and a conductivity-imparting agent to obtain an electrode-forming ink;
Applying the electrode forming ink on a conductive substrate of at least one of a positive electrode and a negative electrode of the secondary battery;
A method for producing a secondary battery comprising:
Provided is a method for manufacturing a secondary battery, wherein the polymer radical material in the dispersion has an average particle size in the range of 2 μm to 25 μm.

Third, the present invention
The ink used for forming the electrode of the secondary battery, wherein at least one of the positive electrode and the negative electrode is an electrode formed using a polymer radical material as an electrode active material and a conductive agent having conductivity,
Electrode formation comprising: the polymer radical material having an average particle diameter in the range of 2 μm to 25 μm; a solvent that does not substantially dissolve or swell the polymer radical material; and the conductivity-imparting agent. Providing ink.

  According to the present invention, the proportion of radical sites that cannot participate in charge / discharge can be reduced, and as a result, a high-capacity secondary battery can be obtained.

Example of configuration of secondary battery of the present invention (perspective view) Example of configuration of secondary battery of the present invention (disassembled perspective view)

  Hereinafter, the present invention will be described in detail with reference to the drawings. However, the present invention is not limited thereto, and various modifications can be made without departing from the gist of the present invention.

  FIG. 1 is a perspective view showing an example of the configuration of the secondary battery of the present invention. FIG. 2 is an exploded perspective view showing an example of the configuration of the secondary battery of the present invention. The battery shown in FIG. 2 has a radical material / conductivity imparting agent positive electrode 1 formed on a positive electrode current collector (aluminum foil) 2 having a positive electrode lead 3 and a negative electrode current collector (metal) having a negative electrode lead 5. The foil 6 has a configuration in which the negative electrode 6 disposed on the foil 7 is overlapped with the separator 4 including the electrolyte solution so as to face each other. These are sealed with an aluminum laminate exterior body (exterior film) 8. In addition, when using solid electrolyte and gel electrolyte as electrolyte solution, it can replace with the separator 4 and can also be made into the form which interposes these electrolytes between electrodes.

  In the secondary battery of the present invention, in such a configuration, the positive electrode 1 or the negative electrode 6 or both electrodes are polymers having a specific particle size (average particle size in the range of 2 μm to 25 μm) in the electrode forming step. It is an electrode (hereinafter also referred to as a specific electrode) formed through a step of forming a layer mainly composed of a radical material and a conductivity-imparting agent. The secondary battery of the present invention preferably uses the above electrode for the positive electrode and a lithium intercalation compound such as lithium or carbon for the negative electrode from the viewpoint that a high voltage can be obtained.

  The main components of the specific electrode in the secondary battery of the present invention are a polymer radical material having a specific particle size and a conductivity imparting agent. This specific electrode is obtained by applying a mixture containing a polymer radical material having a specific particle size (average particle size in the range of 2 μm to 25 μm) and a conductivity imparting agent on a conductive substrate. More specifically, for forming an electrode containing a polymer radical material having a specific particle diameter, a solvent that does not substantially dissolve or swell the polymer radical material, and a conductivity-imparting agent It is formed using ink. In addition, other electrode active materials and conductive agents can be combined. Further, a binder or a thickener can be added for the purpose of increasing the stability of the electrode or facilitating the production.

[1] Polymer Radical Material The polymer radical material used in the present invention functions as an electrode active material in a secondary battery, and is a substance that directly contributes to electrode reactions such as charge reaction and discharge reaction. Here, the step of forming an electrode has a step of forming a dispersion layer formed by dispersing a conductivity imparting agent in a polymer radical material on a conductive substrate. It is essential that the average particle size of the material is in the range of 2 μm to 25 μm. Preferably, the average particle size is in the range of 4 μm to 15 μm. When the average particle size is smaller than 2 μm, the surface area of the polymer radical material becomes too large. For example, in an electrode having a high polymer radical material content, the content of the conductivity-imparting agent is reduced, and the proportion of the polymer radical surface that cannot participate in electron transfer by the conductivity-imparting agent is increased. As a result, the proportion of radical sites that cannot participate in charge / discharge increases. When the average particle size is larger than 25 μm, the electron transfer on the surface of the polymer radical by the conductivity imparting agent functions sufficiently, but many of the radical sites inside the particle cannot participate in the electron migration through the conductivity imparting agent, The proportion of radical sites that cannot participate in charge / discharge increases.

(Measurement of particle size)
The measurement of the particle size is a value obtained using the following equipment.
Particle size measuring instrument: MICROTRAC MT-3000 (manufactured by Nikkiso Co., Ltd.)
Measurement principle: Laser diffraction / scattering type Measurement value: Cumulative average diameter in volume (50% diameter)

  The polymer radical material is a polymer radical material having a nitroxyl radical structure represented by the general formula (1) because the radical itself has high long-term stability and high resistance to redox repetition. It is preferable.

The nitroxyl radical material is a nitroxyl polymer compound having a radical partial structure represented by the general formula (1) in a reduced state and a nitroxyl cation partial structure represented by the general formula (2) in an oxidized state.

  The nitroxyl radical material can be repeatedly charged and discharged by the reaction shown in the following reaction formula (A). This nitroxyl radical material changes its structure from a nitroxyl radical structure to a nitroxyl cation structure during charging, and from a nitroxyl cation structure to a nitroxyl radical structure during discharge (Reaction Formula A).

  The reaction formula (A) represents the electrode reaction of the positive electrode, and the polymer radical material that accompanies such a reaction can function as a material for an electricity storage device that accumulates and releases electrons. Since the oxidation-reduction reaction shown in the reaction formula (A) is a reaction mechanism that does not involve a change in the structure of the organic compound, the reaction rate is high, and if this polymer radical material is used as an electrode material to construct an electricity storage device, it is large at once. It becomes possible to pass an electric current.

  In the present invention, the nitroxyl polymer compound includes a piperidinoxyl radical represented by the general formula (3), a pyrrolidinoxyl radical represented by the general formula (4), and a general compound from the viewpoint of long-term stability. More preferred are those having a group selected from the group consisting of pyrrolinoxyl radicals represented by formula (5), and 2,2,6,6-tetramethylpiperidinoxyl radicals represented by general formula (6). And having a 2,2,5,5-tetramethylpyrrolinoxyl radical represented by the general formula (7) and a 2,2,5,5-tetramethylpyrrolinoxyl radical structure represented by the general formula (8) Those are more preferred.

In the general formulas (3), (4), and (5), R _{1 to} R ₄ each represents an alkyl group having 1 to 4 carbon atoms.

  In the general formulas (6), (7), and (8), Me represents a methyl group.

  Examples of the structure of the main chain polymer include polyalkylene polymers such as polyethylene, polypropylene, polybutene, polydecene, polydodecene, polyheptene, polyisobutene, and polyoctadecene; diene polymers such as polybutadiene, polychloroprene, polyisoprene, and polyisobutene; (Meth) acrylic acid; poly (meth) acrylonitrile; poly (meth) acrylamide polymers such as poly (meth) acrylamide, polymethyl (meth) acrylamide, polydimethyl (meth) acrylamide, polyisopropyl (meth) acrylamide;

  Polyalkyl (meth) acrylates such as polymethyl (meth) acrylate, polyethyl (meth) acrylate, and polybutyl (meth) acrylate; Fluoropolymers such as polyvinylidene fluoride and polytetrafluoroethylene; polystyrene, polybromostyrene, polychlorostyrene Polystyrene polymers such as polymethylstyrene; vinyl polymers such as polyvinyl acetate, polyvinyl alcohol, polyvinyl chloride, polyvinyl methyl ether, polyvinyl carbazole, polyvinyl pyridine, and polyvinyl pyrrolidone;

  Polyether oxides such as polyethylene oxide, polypropylene oxide, polybutene oxide, polyoxymethylene, polyacetaldehyde, polymethyl vinyl ether, polypropyl vinyl ether, polybutyl vinyl ether, polybenzyl vinyl ether; polymethylene sulfide, polyethylene sulfide, polyethylene disulfide, polypropylene sulfide Polysulfide polymers such as polyphenylene sulfide, polyethylene tetrafluoride and polyethylene trimethylene sulfide;

  Polyesters such as polyethylene terephthalate, polyethylene adipate, polyethylene isophthalate, polyethylene naphthalate, polyethylene paraphenylene diacetate, polyethylene isopropylidene dibenzoate; polyurethanes such as polytrimethylene ethylene urethane; polyether ketone, polyallyl ether ketone, etc. Polyketone polymers; Polyanhydride polymers such as polyoxyisophthaloyl; Polyamine polymers such as polyethyleneamine, polyhexamethyleneamine, and polyethylenetrimethyleneamine; Polyamide polymers such as nylon, polyglycine, and polyalanine; Polyacetyl Polyimine polymers such as iminoethylene and polybenzoyliminoethylene; polyesterimide, polyetherimide, Ribenzuimido, polyimide-based polymers such as poly pyromellitic Mel imides;

  Polyarylene, polyarylene alkylene, polyarylene alkenylene, polyphenol, phenol resin, cellulose, polybenzimidazole, polybenzothiazole, polybenzoxazine, polybenzoxazole, olicarborane, polydibenzofuran, polyoxoisoindoline, polyfuran Tetracarboxylic acid diimide, polyoxadiazole, polyoxindole, polyphthalazine, polyphthalide, polycyanurate, polyisocyanurate, polypiperazine, polypiperidine, polypyrazinoquinoxane, polypyrazole, polypyridazine, polypyridine, polypyromellitimine, Polyaromatic polymers such as polyquinone, polypyrrolidine, polyquinoxaline, polytriazine, polytriazole; Siloxane polymers dimethylsiloxane and the like; polysilane polymers; polysilazane-based polymer; polyphosphazene polymers; polythiazyl polymer; can be exemplified polyacetylene, polypyrrole, a conjugated polymer such as polyaniline. In addition, (meth) acryl means methacryl or acrylic.

  Among these, it is preferable to have a polyalkylene polymer, poly (meth) acrylates, poly (meth) acrylamides, and polystyrene as a main chain structure in terms of excellent electrochemical resistance.

  Examples of units possessed by the nitroxyl polymer preferably used in the secondary battery of the present invention include poly (4-methacryloyloxy-2,2,6,6-tetramethylpiperidine represented by the general formula (9): -1-oxyl), poly (4-acryloyloxy-2,2,6,6-tetramethylpiperidine-1-oxyl) represented by the general formula (10), poly (4) represented by the general formula (11) 4-vinyloxy-2,2,6,6-tetramethylpiperidine-1-oxyl), or a copolymer or a crosslinked product containing these as a component is more preferable.

  The molecular weight of the nitroxyl polymer compound used in the secondary battery of the present invention is not particularly limited, but preferably has a molecular weight that makes it difficult to dissolve in the electrolyte when an electricity storage device is constructed. This differs depending on the combination with the type of organic solvent in the electrolyte. In general, the weight average molecular weight is 1,000 or more, preferably 10,000 or more, particularly preferably 20,000 or more. Moreover, as an upper limit, it is 5,000,000 or less, Preferably it is 500,000 or less. In addition, the polymer radical material may be cross-linked, and thereby the solubility in the electrolyte can be lowered, so that the durability against the electrolytic solution can be improved.

  Moreover, in the electrode active material of one electrode of the battery of the present invention, the polymer radical material having a specific particle size used in the present invention can be used alone, but it may be used in combination with other electrode active materials. At this time, it is preferable that 10 to 90 mass% of the polymer radical material having a specific particle size used in the present invention is contained in the electrode active material, and more preferably 20 to 80 mass%.

When the polymer radical material is used for the positive electrode in the secondary battery of the present invention, a metal oxide, a disulfide compound, another stable radical compound, a conductive polymer, or the like can be combined as another electrode active material. Here, as the metal oxide, for example, lithium manganate such as LiMnO ₂ , Li _x Mn ₂ O ₄ (0 <x <2) or lithium manganate having a spinel structure, MnO ₂ , LiCoO ₂ , LiNiO ₂ , Alternatively, Li _y V ₂ O ₅ (0 <y <2), olivine-based material LiFePO ₄ , a material obtained by substituting a part of Mn in the spinel structure with another transition metal, LiNi _0.5 Mn _1.5 O ₄ , LiCr _0.5 Mn _1.5 O ₄ , LiCo _0.5 Mn _1.5 O ₄ , LiCoMnO ₄ , LiNi _0.5 Mn _0.5 O ₂ , LiNi _0.33 Mn _0,33 Co _0.33 O ₂ , _{LiNi 0.8 Co 0.2 O 2, LiN} 0.5 Mn 1.5-z Ti z O 4 (0 <z <1.5), and the like.

  Examples of the disulfide compound include dithioglycol, 2,5-dimercapto-1,3,4-thiadiazole, S-triazine-2,4,6-trithiol and the like.

  Examples of other stable radical compounds include 2,2-diphenylpicryl-1-hydrazyl and galvinoxyl.

  Examples of the conductive polymer include polyacetylene, polyphenylene, polyaniline, and polypyrrole.

Among these, it is particularly preferable to combine with lithium manganate or LiCoO ₂ . In the present invention, these other electrode active materials can be used alone or in combination of two or more.

  In the secondary battery of the present invention, when the polymer radical material is used for the negative electrode, other electrode active materials are not particularly limited, but graphite, amorphous carbon, lithium alloy, conductive polymer, and the like can be used. Moreover, you may use another stable radical compound. These shapes are not particularly limited. For example, metallic lithium is not limited to a thin film shape, and may be a bulk shape, a powdered shape, a fiber shape, a flake shape, or the like. Among these, it is preferable to combine with metallic lithium or graphite. These other electrode active materials can be used alone or in combination of two or more.

  In the secondary battery of the present invention, a polymer radical material having a specific particle size is used in the electrode forming step as an electrode active material in one of the positive electrode and the negative electrode, or in both electrodes. When a radical material is used as the electrode active material, other electrode active materials as exemplified above can be used as the electrode active material in the other electrode. These other electrode active materials can be used alone or in combination of two or more. Furthermore, you may use combining at least 1 sort (s) of these other electrode active materials, and the said polymer radical material. In addition, the polymer radical material can be used alone.

In the secondary battery of the present invention, the polymer radical material only needs to directly contribute to the electrode reaction at the positive electrode or the negative electrode, and the electrode used as the electrode active material is not limited to either the positive electrode or the negative electrode. Absent. However, from the viewpoint of energy density, it is particularly preferable to use this polymer radical material as the positive electrode active material. At this time, it is preferable to use this polymer radical material alone as the positive electrode active material. However, it can also be used in combination with another positive electrode active material, and as the other positive electrode active material, lithium manganate or LiCoO ₂ is preferable. Further, when the above positive electrode active material is used, it is preferable to use metallic lithium or graphite as the negative electrode active material.

[2] Conductivity imparting agent Examples of the conductivity imparting agent include carbon materials such as activated carbon, graphite, carbon black, acetylene black, and carbon fiber; and conductive polymers such as polyacetylene, polyphenylene, polyaniline, and polypyrrole. In particular, carbon fiber is preferable. As the carbon fiber, one having an average fiber diameter of 50 nm to 300 nm is more preferable.

[3] Binder A binder can also be used to strengthen the connection between the constituent materials of the electrode. Examples of such binders include polytetrafluoroethylene, polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-tetrafluoroethylene copolymer, styrene / butadiene copolymer rubber, polypropylene, and polyethylene. Resin binders such as polyimide and various polyurethanes. These binders can be used alone or in admixture of two or more. As a ratio of the binder in an electrode, 5-30 mass% is preferable.

[4] Thickener The secondary battery of the present invention has a high molecular weight material by mixing and dispersing the polymer radical material in a solvent that does not substantially dissolve or swell the polymer radical material in the electrode forming step. It has the process which makes the average particle diameter of molecular radical material the range of 2 micrometers-25 micrometers. In order to make it easy to produce an electrode slurry that is a dispersion of a polymer radical material, a thickener can also be used. Such thickeners include carboxymethyl cellulose, polyethylene oxide, polypropylene oxide, hydroxyethyl cellulose, hydroxypropyl cellulose, carboxymethyl hydroxyethyl cellulose, polyvinyl alcohol, polyacrylamide, hydroxyethyl polyacrylate, ammonium polyacrylate, polyacrylic acid Examples include soda. These thickeners can be used alone or in admixture of two or more. As a ratio of the thickener in an electrode, 0.1-5 mass% is preferable.

[5] Catalyst The secondary battery of the present invention can also use a catalyst that assists the oxidation-reduction reaction in order to perform the electrode reaction more smoothly. Examples of such catalysts include conductive polymers such as polyaniline, polypyrrole, polythiophene, polyacetylene, and polyacene; basic compounds such as pyridine derivatives, pyrrolidone derivatives, benzimidazole derivatives, benzothiazole derivatives, and acridine derivatives; and metal ion complexes. Can be mentioned. These catalysts can be used alone or in admixture of two or more. The ratio of the catalyst in the electrode is preferably 10% by mass or less.

[6] Current collector and separator As the negative electrode current collector and the positive electrode current collector, foils made of nickel, aluminum, copper, gold, silver, aluminum alloy, stainless steel, carbon, etc., metal flat plates, mesh shapes, etc. Things can be used. From the viewpoint of potential stability, the positive electrode current collector is particularly preferably an aluminum foil, and the negative electrode current collector is preferably a copper foil. The current collector may have a catalytic effect, or the electrode active material and the current collector may be chemically bonded.

  On the other hand, a separator such as a porous film or non-woven fabric made of polyethylene, polypropylene, or the like can be used so that the positive electrode and the negative electrode are not in contact with each other.

[7] Electrolyte In the secondary battery of the present invention, the electrolyte performs charge carrier transport between the negative electrode and the positive electrode, and generally has an ionic conductivity of 10 ⁻⁵ to 10 ⁻¹ S / cm at 20 ° C. It is preferable to have. As the electrolyte, for example, an electrolytic solution in which an electrolyte salt is dissolved in a solvent can be used. Examples of the electrolyte salt include LiPF ₆ , LiClO ₄ , LiBF ₄ , LiCF ₃ SO ₃ , Li (CF ₃ SO ₂ ) ₂ N, Li (C ₂ F ₅ SO ₂ ) ₂ N, Li (CF ₃ SO ₂ ) ₃ C A material such as Li (C ₂ F ₅ SO ₂ ) ₃ C can be used. These electrolyte salts can be used alone or in admixture of two or more.

  When a solvent is used for the electrolytic solution, examples of the solvent include ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, γ-butyrolactone, tetrahydrofuran, dioxolane, sulfolane, N, N-dimethylformamide, N, Organic solvents such as N-dimethylacetamide and N-methyl-2-pyrrolidone can be used. These solvents can be used alone or in admixture of two or more.

  Furthermore, in the secondary battery of the present invention, a solid electrolyte can be used as the electrolyte. Polymer compounds used for the solid electrolyte include polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-ethylene copolymer, vinylidene fluoride-monofluoroethylene copolymer, vinylidene fluoride- Vinylidene fluoride polymers such as trifluoroethylene copolymer, vinylidene fluoride-tetrafluoroethylene copolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer; acrylonitrile-methyl methacrylate copolymer , Acrylonitrile-methyl acrylate copolymer, acrylonitrile-ethyl methacrylate copolymer, acrylonitrile-ethyl acrylate copolymer, acrylonitrile-methacrylic acid copolymer, acrylonitrile-acrylic acid copolymer Coalescence, acrylonitrile - acrylonitrile polymers such as vinyl acetate copolymer; and polyethylene oxide, ethylene oxide - propylene oxide copolymers, and polymers of these acrylates body or methacrylate body thereof. These polymer compounds may be used in the form of a gel containing an electrolytic solution, or only a polymer compound containing an electrolyte salt may be used as it is.

[8] Production of electrode The production method of the electrode is not particularly limited, and a method appropriately selected according to the material can be used. However, for a specific electrode, the polymer radical material is mixed and dispersed in a solvent (medium) that does not substantially dissolve or swell so that the average particle diameter of the polymer radical material is in the range of 2 μm to 25 μm. Is preferred. Here, as a dispersion method, for example, a bead mill, a roll mill, a kneader, or the like can be used. Among these, a bead mill is more preferable.

The polymer radical material is made into a slurry-like uniform dispersion (dispersion) with an average particle diameter in the range of 2 to 25 μm, and an electrode ink in which a conductive material is mixed is applied to the electrode current collector. And the method of obtaining an electrode by volatilizing a solvent by heating or normal temperature is preferable.
Here, water is preferable as the solvent (medium) that does not substantially dissolve or swell the polymer radical material. The mass ratio between the polymer radical material and the conductivity-imparting agent (ratio of polymer radical material to conductivity-imparting agent, polymer radical material / conductivity-imparting agent) is desirably in the range of 1.5 to 18. Furthermore, it is more desirable to be in the range of 2 to 13.

A method used for applying the electrode forming ink to the electrode current collector to produce a positive electrode or a negative electrode is not particularly limited, but a printing method or a coating method can be used.
For example, a screen printing method, a rotary screen printing method, a gravure printing method, a gravure offset printing method, a flexographic printing method, a die coating method, a cap coating method, a roll coating method and the like can be used.

In addition, when preparing an electrode, as an electrode active material, using a polymer radical material itself having a specific particle size, and using a polymer that changes to a polymer radical material used in the present invention by an electrode reaction. There is a case to do. Examples of the polymer that changes to the polymer radical material by such an electrode reaction include a lithium salt or a sodium salt comprising an anion body obtained by reducing the polymer radical material and an electrolyte cation such as lithium ion or sodium ion, Alternatively, the cation body by oxidizing the polymer radical material and PF ₆ ^- and BF ₄ ^- salts consisting of the electrolyte anions, and the like.

[9] Battery shape In the secondary battery of the present invention, the shape of the battery is not particularly limited. Examples of the battery shape include an electrode laminate or a wound body sealed with a metal case, a resin case, or a laminate film made of a metal foil such as an aluminum foil and a synthetic resin film, etc. A mold, a coin mold, and a sheet mold are used, but the present invention is not limited to these.

[10] Battery manufacturing method Examples include a method of laminating or winding an electrode with a counter electrode and a separator interposed therebetween, wrapping it with an outer package, and injecting an electrolyte solution to seal it. When manufacturing a battery, a battery is manufactured using a polymer radical material itself as an electrode active material and a polymer that changes into a polymer radical material used in the present invention by an electrode reaction. There are cases.

  In the secondary battery of the present invention, other manufacturing conditions such as lead extraction from the electrode and exterior are not particularly limited.

  Hereinafter, although the detail of this invention is concretely demonstrated by a synthesis example and an Example, this invention is not limited to these Examples.

Example 1
To 48.6 g of water, a polymer radical material corresponding to the aforementioned general formula (11), poly (4-vinyloxy-2,2,6,6-tetramethylpiperidine-1-oxyl (hereinafter PTVE: theoretical capacity 135 mAh / g) 8 g was added and dispersed by a bead mill to obtain a polymer radical dispersion having an average particle size of 9 μm (measured by Nikkiso MICROTRAC MT-3000), and then a conductivity-imparting agent carbon fiber carbon nanofiber VGCF 2.85 g of VGCF (Showa Denko), 0.11 g of binder polytetrafluoroethylene (hereinafter PTFE: manufactured by Daikin Industries), and 0.46 g of thickener carboxymethylcellulose (hereinafter CMC: Daicel Industries) were added with a stirrer. The mixture was stirred until uniform to obtain an electrode forming ink.The obtained electrode forming ink was used as a metal mask (stainless steel). ) Stencil printing (Neurong Seimitsu Kogyo screen printing machine LS-150), coated on an aluminum current collector, dried in a vacuum oven, and then pressed to form a positive electrode having a thickness of 88 μm and a width of 25 × 16 mm. Obtained.

An aluminum lead having a length of 65 mm and a width of 0.4 mm was welded to the aluminum foil surface of the positive electrode. Further, a lithium-laminated copper foil (lithium thickness 30 μm) was punched into a 25 × 16 mm rectangle like the positive electrode to form a metal lithium negative electrode, and a nickel lead 65 mm long and 0.4 mm wide was welded to the copper foil surface. A positive electrode, a porous polypropylene separator (30 × 20 mm rectangle), and a negative electrode were stacked in this order to face the radical positive electrode layer and the metal lithium negative electrode to form a power storage unit. Two sheets of aluminum laminate film (length 58 mm × width 52 mm × thickness 0.12 mm) that can be heat-sealed were heat-sealed to form a bag-like case, and a power storage unit was placed. The electrolytic solution [ethylene carbonate / diethyl carbonate mixed solution containing 1.0 mol / L LiPF ₆ electrolyte salt (mixing volume ratio 3: 7)] was added to the aluminum laminate case.

  At this time, the ends of the aluminum and nickel leaded electrodes were taken out of 2.7 cm, and one side of the unlaminated aluminum laminate case was heat-sealed at a low pressure of 1.6 mmHg. As a result, the electrode and the electrolyte were completely sealed in the aluminum laminate case. As described above, a thin organic radical battery (length 58 mm × width 52 mm × thickness 0.3 mm) was produced.

  The charge capacity when this battery was charged at 0.1 C was measured. As a result, a battery capacity value of 111 mAh / g was obtained. MAh / g represents the charge capacity per 1 g of the polymer radical material.

(Example 2)
An electrode was produced in the same manner as in Example 1 except that a polymer radical dispersion having an average particle size of 15 μm was obtained by a bead mill, and a positive electrode having a thickness of 87 μm was obtained. Thereafter, a thin organic radical battery (length 58 mm × width 52 mm × thickness 0.3 mm) was produced in the same manner as in Example 1.
The charge capacity when this battery was charged at 0.1 C was measured. As a result, a battery capacity value of 102 mAh / g was obtained.

(Example 3)
An electrode was produced in the same manner as in Example 1 except that a polymer radical dispersion having an average particle size of 25 μm was obtained by a bead mill, and a positive electrode having a thickness of 79 μm was obtained. Thereafter, a thin organic radical battery (length 58 mm × width 52 mm × thickness 0.3 mm) was produced in the same manner as in Example 1.
The charge capacity when this battery was charged at 0.1 C was measured. As a result, a battery capacity value of 99 mAh / g was obtained.

Example 4
An electrode was produced in the same manner as in Example 1 except that a polymer radical dispersion having an average particle size of 7 μm was obtained by a bead mill, and a positive electrode having a thickness of 84 μm was obtained. Thereafter, a thin organic radical battery (length 58 mm × width 52 mm × thickness 0.3 mm) was produced in the same manner as in Example 1. The charge capacity when this battery was charged at 0.1 C was measured. As a result, a battery capacity value of 110 mAh / g was obtained.

(Example 5)
An electrode was produced in the same manner as in Example 1 except that a polymer radical dispersion having an average particle size of 3 μm was obtained by a bead mill, and a positive electrode having a thickness of 110 μm was obtained. Thereafter, a thin organic radical battery (length 58 mm × width 52 mm × thickness 0.3 mm) was produced in the same manner as in Example 1. The charge capacity when this battery was charged at 0.1 C was measured. As a result, a battery capacity value of 92 mAh / g was obtained.

(Comparative Example 1)
An electrode was produced in the same manner as in Example 1 except that a polymer radical dispersion having an average particle size of 1 μm was obtained by a bead mill, and a positive electrode having a thickness of 86 μm was obtained. Thereafter, a thin organic radical battery (length 58 mm × width 52 mm × thickness 0.3 mm) was produced in the same manner as in Example 1. The charge capacity when this battery was charged at 0.1 C was measured. As a result, a battery capacity value of 55 mAh / g was obtained.

(Comparative Example 2)
An electrode was produced in the same manner as in Example 1 except that a polymer radical dispersion having an average particle size of 30 μm was obtained by a bead mill, and a positive electrode having a thickness of 122 μm was obtained. Thereafter, a thin organic radical battery (length 58 mm × width 52 mm × thickness 0.3 mm) was produced in the same manner as in Example 1.
The charge capacity when this battery was charged at 0.1 C was measured. As a result, a battery capacity value of 87 mAh / g was obtained.

  As described above, the step of forming an electrode includes the step of forming a dispersion layer formed by dispersing a conductivity-imparting agent in a polymer radical material on a conductive substrate. When the average particle size of the material was in the range of 2 μm to 25 μm, a high battery capacity of 90 mAh / g or more was shown.

  The secondary battery of the present invention is a thin layer type and has a high battery capacity, and contributes to reducing the size and weight of various electronic devices.

1 radical material / conductivity imparting agent positive electrode, 2 positive electrode current collector, 3 positive electrode lead, 4 separator, 5 negative electrode lead, 6 negative electrode, 7 negative electrode current collector, 8 aluminum laminate exterior.

That is, the present invention firstly
A secondary battery comprising a positive electrode and a negative electrode,
On the conductive substrate of at least one of the positive electrode and the negative electrode, a mixture containing a polymer radical material as an electrode active material and a conductivity-imparting agent is applied,
Provided is a secondary battery wherein the polymer radical material has an average particle size in the range of 4 μm to 15 μm.

The present invention secondly,
Dispersing a polymer radical material as an electrode active material in a medium in which the polymer radical material is not substantially dissolved or swollen to obtain a dispersion;
Mixing the dispersion and a conductivity-imparting agent to obtain an electrode-forming ink;
Applying the electrode forming ink on a conductive substrate of at least one of a positive electrode and a negative electrode of the secondary battery;
A method for producing a secondary battery comprising:
Provided is a method for producing a secondary battery, wherein the polymer radical material in the dispersion has an average particle size in the range of 4 μm to 15 μm.

Third, the present invention
The ink used for forming the electrode of the secondary battery, wherein at least one of the positive electrode and the negative electrode is an electrode formed using a polymer radical material as an electrode active material and a conductive agent having conductivity,
It contains the polymer radical material having an average particle size in the range of 4 μm to 15 μm, a solvent that does not substantially dissolve or swell the polymer radical material, and the conductivity-imparting agent. An electrode forming ink is provided.

(Example 3 (reference example) )
An electrode was produced in the same manner as in Example 1 except that a polymer radical dispersion having an average particle size of 25 μm was obtained by a bead mill, and a positive electrode having a thickness of 79 μm was obtained. Thereafter, a thin organic radical battery (length 58 mm × width 52 mm × thickness 0.3 mm) was produced in the same manner as in Example 1.
The charge capacity when this battery was charged at 0.1 C was measured. As a result, a battery capacity value of 99 mAh / g was obtained.

(Example 5 (reference example) )
An electrode was produced in the same manner as in Example 1 except that a polymer radical dispersion having an average particle size of 3 μm was obtained by a bead mill, and a positive electrode having a thickness of 110 μm was obtained. Thereafter, a thin organic radical battery (length 58 mm × width 52 mm × thickness 0.3 mm) was produced in the same manner as in Example 1. The charge capacity when this battery was charged at 0.1 C was measured. As a result, a battery capacity value of 92 mAh / g was obtained.

That is, the present invention firstly
A secondary battery comprising a positive electrode and a negative electrode,
On the conductive substrate of at least one of the positive electrode and the negative electrode, a mixture containing a polymer radical material as an electrode active material and a conductivity-imparting agent is applied,
Ri range near the mean particle size from 4μm of 15μm of the polymer radical material,
The polymer radical material is poly (4-vinyloxy-2,2,6,6-tetramethylpiperidine-1-oxyl), poly (4-methacryloyloxy-2,2,6,6-tetramethylpiperidine-1). -Oxyl), poly (4-acryloyloxy-2,2,6,6-tetramethylpiperidine-1-oxyl), or a copolymer containing these as a component is provided. .

The present invention secondly,
Dispersing a polymer radical material as an electrode active material in a medium in which the polymer radical material is not substantially dissolved or swollen to obtain a dispersion;
Mixing the dispersion and a conductivity-imparting agent to obtain an electrode-forming ink;
Applying the electrode forming ink on a conductive substrate of at least one of a positive electrode and a negative electrode of the secondary battery;
A method for producing a secondary battery comprising:
Ri range near the mean particle size of 15μm from 4μm polymeric radical material in the dispersion,
The polymer radical material is poly (4-vinyloxy-2,2,6,6-tetramethylpiperidine-1-oxyl), poly (4-methacryloyloxy-2,2,6,6-tetramethylpiperidine-1). -Oxyl), poly (4-acryloyloxy-2,2,6,6-tetramethylpiperidine-1-oxyl), or a copolymer containing these as components, a method for producing a secondary battery I will provide a.

Third, the present invention
The ink used for forming the electrode of the secondary battery, wherein at least one of the positive electrode and the negative electrode is an electrode formed using a polymer radical material as an electrode active material and a conductive agent having conductivity,
The polymer radical material having an average particle size in the range of 4 μm to 15 μm, a solvent that does not substantially dissolve or swell the polymer radical material, and the conductivity-imparting agent ,
The polymer radical material is poly (4-vinyloxy-2,2,6,6-tetramethylpiperidine-1-oxyl), poly (4-methacryloyloxy-2,2,6,6-tetramethylpiperidine-1). -Oxyl), poly (4-acryloyloxy-2,2,6,6-tetramethylpiperidine-1-oxyl), or a copolymer containing these as a component is provided. To do.

Claims (13)

A secondary battery comprising a positive electrode and a negative electrode,
On the conductive substrate of at least one of the positive electrode and the negative electrode, a mixture containing a polymer radical material as an electrode active material and a conductivity-imparting agent is applied,
A secondary battery, wherein the polymer radical material has an average particle size in the range of 2 μm to 25 μm. The mixture is an electrode forming ink containing a medium that does not substantially dissolve or swell the polymer radical material,
The secondary battery according to claim 1, wherein the electrode forming ink is applied on the conductive substrate and then dried.   The secondary battery according to claim 2, wherein the medium is an aqueous medium.   The secondary battery according to claim 1, wherein the conductivity-imparting agent is carbon fiber.   The secondary battery according to claim 4, wherein an average fiber diameter of the carbon fibers is in a range of 50 nm to 300 nm.   The secondary battery according to claim 1, wherein a mass ratio of the polymer radical material to the conductivity-imparting agent is in a range of 1.5 to 18. The secondary battery according to claim 1, wherein the polymer radical material is a polynitroxide radical compound having a nitroxide radical structure represented by the general formula (1) in a repeating unit.

  The polynitroxide radical compound is poly (4-methacryloyloxy-2,2,6,6-tetramethylpiperidine-1-oxyl), poly (4-acryloyloxy-2,2,6,6-tetramethylpiperidine- The secondary battery according to claim 7, which is 1-oxyl) or a copolymer containing these as components.   8. The polynitroxide radical compound is poly (4-vinyloxy-2,2,6,6-tetramethylpiperidine-1-oxyl) or a copolymer containing this as a component. The secondary battery as described.   The secondary battery according to claim 7, wherein the polynitroxide radical compound has a crosslinked structure.   The secondary battery according to claim 1, wherein the secondary battery is a lithium secondary battery. Dispersing a polymer radical material as an electrode active material in a medium in which the polymer radical material is not substantially dissolved or swollen to obtain a dispersion;
Mixing the dispersion and a conductivity-imparting agent to obtain an electrode-forming ink;
Applying the electrode forming ink on a conductive substrate of at least one of a positive electrode and a negative electrode of the secondary battery;
A method for producing a secondary battery comprising:
The method for producing a secondary battery, wherein the polymer radical material in the dispersion has an average particle size in the range of 2 μm to 25 μm.
A polymer radical material as an electrode active material;
A solvent that does not substantially dissolve or swell the polymeric radical material;
A conductivity-imparting agent;
An electrode forming ink comprising:
An electrode forming ink, wherein the polymer radical material has an average particle size in the range of 2 μm to 25 μm.

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