JP5176129B2 - Polyradical compounds and batteries - Google Patents

Description

  The present invention relates to a polyradical compound capable of repeating stable redox when applied to an electrode active material of a secondary battery, and a secondary battery using the same.

  In recent years, portable electronic devices such as notebook computers and mobile phones have rapidly spread with the development of communication systems. While mobile electronic devices are becoming more sophisticated, functions and shapes are also diversifying. Therefore, demands such as small size, light weight and high energy density are increasing for the battery as the power source.

  In order to obtain a light battery having a large energy density, a battery using a sulfur compound or an organic compound as an electrode active material has been developed. For example, Patent Documents 1 and 2 disclose batteries using an organic compound having a disulfide bond as a positive electrode. This is an electrochemical redox reaction involving generation and dissociation of disulfide bonds, which is used as a battery principle. 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, a stable charge / discharge cycle cannot be performed because the dissociated bond has low recombination efficiency and the electrode active material diffuses into the electrolyte. Therefore, there is a drawback that the capacity tends to decrease when the charge / discharge cycles are repeated.

  As a battery using an organic compound, a battery using a conductive polymer as an electrode material has been proposed. This is a battery based on the principle of doping and dedoping of electrolyte ions with respect to a conductive polymer. The dope reaction is a reaction in which a charged radical generated by oxidation or reduction of a conductive polymer is stabilized by a counter ion. Patent Document 3 discloses a battery using such 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 generated charged radicals, that is, the doping concentration, and 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. Although a battery using a conductive polymer as an electrode material has a certain effect in terms of weight reduction, a battery having a large energy density has not been obtained.

As a battery using an organic compound as an electrode active material, a battery using a redox reaction of a radical compound has been proposed. For example, Patent Document 4 discloses an organic radical compound such as a nitroxide radical compound, an aryloxy radical compound, and a polymer compound having a specific aminotriazine structure as an active material, and the organic radical compound is used as a positive electrode or a negative electrode. A battery used as a material is disclosed. Further, Patent Document 5 discloses a power storage device using a compound having a cyclic nitroxide structure as an electrode active material among nitroxide compounds. The polyradical compound used as the electrode active material includes poly (2,2,6,6-tetramethylpiperidine-1-oxyl) having 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO). Nitroxide radical compounds such as 4-yl methacrylate) (PTMA) are used. When a polyradical compound is used as the electrode active material, the limitation of the doping rate seen in the conductive polymer is improved. For example, when PTMA is applied to the battery, the oxidation-reduction doping rate is 70% (˜80 mAh / g). More than that.
US Pat. No. 4,833,048 Japanese Patent No. 2715778 U.S. Pat. No. 4,442,187 JP 2002-151084 A JP 2002-304996 A

  Radical redox includes p-type redox between neutral radicals and cations and n-type redox between neutral radicals and anions. When a radical compound exhibiting n-type redox is used, when a battery is produced, the movement of lithium ions accompanying the charge / discharge reaction takes a form of reciprocating between the positive electrode and the negative electrode (so-called rocking chair type). In the case of a battery using a radical compound exhibiting n-type redox, the electrolyte concentration is constant regardless of the depth of charge / discharge. On the other hand, in the case of a battery using a radical compound exhibiting p-type redox, the anion of the electrolyte salt is doped into the polymer, the electrolyte concentration decreases with the progress of charging, and conversely, the electrolyte concentration increases due to discharge. For this reason, in the case of p-type redox, it is necessary to store an anion serving as a dopant in the electrolytic solution, and a large amount of electrolytic solution is required. For this reason, even if the oxidation / reduction is performed at a high doping rate, the battery weight is increased due to the use of a large amount of the electrolyte, resulting in a lower energy density.

  In the case of a nitroxide radical compound typified by TEMPO, p-type redox is a stable reaction that can be reversibly repeated in a non-aqueous electrolyte. On the other hand, n-type redox cannot be repeated with a decomposition reaction. Therefore, in order to use p-type redox as an electrode reaction, it is necessary to keep an amount of anion necessary for doping in the electrolytic solution in the electrolytic solution, and an electrode active material that performs n-type redox Compared with the case of using a large amount of electrolyte solution. This large amount of electrolyte has caused a reduction in the energy density of the battery.

  An object of the present invention is to provide a polyradical compound that can stably perform n-type oxidation-reduction and can stably charge and discharge when applied to a battery, and a battery using the polyradical compound as an electrode active material. It is said.

  As a result of intensive studies by the present inventors, a specific organic compound that has not been used as an electrode active material until now, that is, a repeating structural unit represented by the formula (1), and a polymerizable group in the molecule It has been found that the above-mentioned problems can be solved by using, as an electrode active material, a polyradical compound having a structure crosslinked with two or more polyfunctional crosslinking agents. That is, according to the present invention, the repeating structural unit represented by the general formula (1) can stably perform n-type redox, and has a polyfunctionality having two or more polymerizable groups in the molecule. By cross-linking with this cross-linking agent, there is no elution into the electrolyte solution, and a stable charge / discharge cycle can be repeated.

  The present invention is a polyradical compound having a structure crosslinked by a polyfunctional crosslinking agent having a repeating structural unit represented by the following formula (1) and having two or more polymerization groups in the molecule. The present invention also provides a battery comprising at least a positive electrode, a negative electrode, and an electrolyte, wherein the polyradical compound of the present invention is used as an electrode active material of at least one of the positive electrode and the negative electrode. It is.

  Furthermore, it has been found that a compound represented by the following general formula (2a) is suitable as a polyfunctional crosslinking agent having two or more polymerizable groups in the molecule.

(In General Formula (2a), X represents a linear, branched or cyclic alkylenedioxy group having 1 to 12 carbon atoms, or a structure represented by General Formula (3). R ¹ is independently a hydrogen atom. Or represents a methyl group.)

(In general formula (3), k represents an integer of 2 to 8.)
In the battery of the present invention, the polyradical compound performs an oxidation-reduction reaction as shown in the following scheme (I) in the process of charging and discharging. In the oxidation-reduction reaction of Scheme (I), when a polymer is used for the positive electrode, the state changes from (A) to (B) by charging, and electrons are released. The state changes from (B) to (A) by discharging, and receives electrons.

  In the battery, since the electrode active material is oxidized or reduced by charge and discharge, the electrode active material takes two states, a starting state and an oxidation state. That is, the polyradical compound of the present invention performs n-type redox (redox between a neutral radical and an anion). In the present invention, the electrode active material has a repeating structural unit represented by the general formula (1) in either a charged state or a discharged state.

  The present invention relates to a polyradical compound having a structure crosslinked in a molecule by a polyfunctional crosslinking agent having a repeating structural unit represented by the general formula (1) and having two or more polymerizable groups in the molecule. Has been made based on the finding that is excellent as an electrode active material. This is because the polyradical compound causes an n-type redox reaction that is reversibly stable at a rate of almost 100%, causing little side reaction. That is, a battery using the polyradical compound as an electrode active material can be stably charged and discharged, and has excellent cycle characteristics. In addition, since the polyradical compound performs n-type redox, when a battery is produced using the polyradical compound as an electrode active material, the amount of electrolyte required may be very small. Moreover, the said polyradical compound can be comprised only from elements with small mass, such as carbon, nitrogen, hydrogen, and oxygen. For this reason, the mass of the electrode active material can be reduced, and the capacity density per unit mass of an electrode manufactured using the same can be increased. As a result, when a battery is produced using this electrode active material, the energy density per mass is Becomes a big battery.

  In the present invention, the polyradical compound only needs to directly contribute to the electrode reaction at the positive electrode or the negative electrode, and the electrode using the electrode active material is not limited to either the positive electrode or the negative electrode. However, from the viewpoint of energy density, it is particularly preferable to use this polyradical compound as the positive electrode active material. In addition, the battery of the present invention is preferably a lithium battery using carbon in which metallic lithium or lithium ions can be inserted and removed from the negative electrode, particularly a lithium secondary battery, from the viewpoint that a high voltage and a large capacity can be obtained.

  The present invention contains a polyradical compound having a structure crosslinked by a polyfunctional crosslinking agent having a repeating structural unit represented by the general formula (1) and having two or more polymerizable groups in the molecule. An electrode active material has been proposed. Thereby, it is possible to provide an electrode active material having a high capacity density and capable of extracting a large current, and an electrode having a high energy density and capable of outputting a large output. Therefore, according to the present invention, it is possible to produce a battery composed of a light and safe element that does not contain heavy metals as an electrode active material, and has a high capacity (per mass) and a charge / discharge cycle. It is possible to realize a battery that is excellent in stability and can produce a larger output.

  FIG. 2 is a perspective view of one embodiment of the battery of the present invention, and FIG. 1 shows the configuration of one embodiment of the battery of the present invention. The battery shown in FIGS. 1 and 2 includes a positive electrode 11 formed on a current collector (metal foil) having a + tab 14 and a negative electrode 13 arranged on a current collector (metal foil) having a −tab 15. With the separator 12 containing the electrolyte so as to face each other. These are sealed with an aluminum laminate exterior body (exterior film) 16. In addition, when using solid electrolyte and gel electrolyte as electrolyte, it can replace with the separator 12 and can also be made into the form which interposes these electrolytes between electrodes.

  In the present invention, in such a configuration, the positive electrode 11 or the negative electrode 13 or the electrode active material used for both electrodes has a repeating structural unit represented by the general formula (1), and 2 polymerizable groups are present in the molecule. It is an electrode active material containing a polyradical compound having a structure crosslinked by a polyfunctional crosslinking agent having at least one.

  The battery of the present invention preferably uses the above electrode active material as the positive electrode active material and a lithium intercalation compound such as lithium or carbon for the negative electrode because a high voltage can be obtained.

[1] Electrode active material The electrode active material of the electrode in the present invention is a material that directly contributes to electrode reactions such as charge reaction and discharge reaction, and plays a central role in the battery system.

  In the present invention, the electrode active material has a structure having a repeating structural unit represented by the general formula (1) and a structure crosslinked by a polyfunctional crosslinking agent having two or more polymerizable groups in the molecule. An electrode active material containing a radical compound is used. In addition, “tBu” in the general formula (1) is a tertiary butyl group.

  As the polyfunctional crosslinking agent having two or more polymerizable groups in the molecule, a crosslinking agent represented by the general formula (2a) is suitable.

(In General Formula (2a), X represents a linear, branched or cyclic alkylenedioxy group having 1 to 12 carbon atoms, or a structure represented by General Formula (3). R ¹ is independently a hydrogen atom. Or represents a methyl group.)

(In general formula (3), k represents an integer of 2 to 8.)
That is, the repeating structural unit represented by the general formula (1) is preferably crosslinked by a structure represented by the following general formula (2b).

(In General Formula (2b), X represents a linear, branched or cyclic alkylenedioxy group having 1 to 12 carbon atoms, or a structure represented by General Formula (3). R ¹ is independently a hydrogen atom. Or represents a methyl group.)

(In general formula (3), k represents an integer of 2 to 8.)
In the general formulas (2a) and (2b), the alkylenedioxy group is preferably an ethylenedioxy group.

  As the cross-linking agent, in addition to the above, a polyfunctional cross-linking agent having two or more polymerizable groups in a molecule used as a general poly ((meth) acrylate) cross-linking agent can be used. Among these, as the bifunctional crosslinking agent, 1,4-divinylbenzene, 2,2-bis (4-vinylphenyl) propane, 4,4′-divinylbiphenyl, 1- (4-vinylphenoxy) -4 -Aromatic divinyl compounds such as vinyl benzene; ethylene glycol divinyl ether, propylene glycol divinyl ether, butylene glycol divinyl ether, alkylene glycol divinyl ether compounds such as pentylene glycol divinyl ether; di (ethylene glycol) divinyl ether, tri (ethylene glycol) ) Polyethylene glycol divinyl ether compounds such as divinyl ether; cyclohexane ring-containing divinyl ether compounds such as cyclohexane dimethanol divinyl ether can be used.

  In the battery of the present invention, the electrode active material is preferably fixed to the electrode. However, in that case, in order to suppress a decrease in capacity due to dissolution in the electrolytic solution, it is preferably insoluble or low-soluble in the electrolytic solution in a solid state. At this time, if it is insoluble in the electrolytic solution, it may swell. This is because when the solubility in the electrolytic solution is high, the electrode active material is eluted from the electrode into the electrolytic solution, so that the capacity may decrease with the charge / discharge cycle.

  For this reason, it is preferable that the polyradical compound of this invention does not melt | dissolve in organic solvents, such as acetonitrile.

  The molar ratio of the repeating structural unit represented by the general formula (1) and the structure crosslinked by the crosslinking agent is preferably 10: 1 to 1000: 1, more preferably 10: 1 to 100: 1.

  Examples of the polyradical compound of the present invention include polyradical compounds represented by the following formulas (4) to (10).

  The polyradical compound of the present invention can be synthesized, for example, by the route shown in the following synthesis scheme (11). First, 2,6-tert-butylphenol is used as a starting material, brominated, hydroxyl group protected with tetramethylsilyl, then lithiated, and then reacted with methyl p-bromobenzoate. After deprotection (elimination of the tetramethylsilyl group), (p-bromophenyl) hydrogalvinoxyl is obtained, and further a vinyl group is introduced by Still coupling to form a monomer. This is made into a crosslinked polymer by copolymerizing with a bifunctional crosslinking agent having two polymerizable groups in the molecule. In this method, radicals are generated by oxidizing a polymer with potassium ferricyanide to obtain a polyradical compound having a crosslinked structure.

  Moreover, although the polyradical compound of this invention can be used independently in the electrode active material of one pole of the battery of this invention, you may use it in combination of 2 or more types. Moreover, you may use in combination with another electrode active material. At this time, it is preferable that 10-90 mass% of the polyradical compound of this invention is contained in the electrode active material, and it is more preferable that 20-80 mass% is contained.

When the polyradical compound of the present invention is used for the positive electrode, 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, examples of the metal oxide include lithium manganate such as LiMnO ₂ and 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 , materials in which a part of Mn in the spinel structure is substituted 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. Other stable radical compounds include poly (2,2,6,6-tetramethylpiperidin-1-oxyl-4-yl methacrylate) and the like. 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.

  When the polyradical compound of the present invention is used for the negative electrode, graphite, amorphous carbon, metallic lithium or lithium alloy, lithium ion storage carbon, metallic sodium, conductive polymer, etc. can be used as other electrode active materials. . Moreover, you may use another stable radical compound. Other stable radical compounds include poly (2,2,6,6-tetramethylpiperidin-1-oxyl-4-yl methacrylate) and the like. 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.

  The battery of the present invention uses the polyradical compound of the present invention as an electrode active material in one electrode reaction of the positive electrode or the negative electrode, or both electrode reactions. Conventionally known electrode active materials such as those exemplified above can be used as the electrode active material in these electrodes. These electrode active materials can be used alone or in combination of two or more. Further, at least one of these electrode active materials may be used in combination with the polyradical compound of the present invention. Moreover, the polyradical compound of this invention can also be used independently.

In the present invention, it is sufficient that the polyradical compound of the present invention directly contributes 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. However, from the viewpoint of energy density, it is particularly preferable to use this polyradical compound as the positive electrode active material. At this time, it is preferable to use this polyradical compound 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 at that time, lithium manganate or LiCoO ₂ is preferable. Furthermore, when using said positive electrode active material, it is preferable to use metallic lithium or graphite as a negative electrode active material.

[2] Conductivity-imparting agent (auxiliary conductive material) and ion-conductivity auxiliary material When the electrode is formed using the polyradical compound of the present invention, conductivity is imparted for the purpose of reducing impedance and improving energy density and output characteristics. An agent (auxiliary conductive material) or an ion conduction auxiliary material can be mixed. Examples of auxiliary conductive materials include carbonaceous fine particles such as graphite, carbon black, and acetylene black; carbon fibers such as vapor grown carbon fiber (VGCF) and carbon nanotube; conductive polymers such as polyaniline, polypyrrole, polythiophene, polyacetylene, and polyacene. Is mentioned. Examples of the ion conduction auxiliary material include a polymer gel electrolyte and a polymer solid electrolyte. Among these, it is preferable to mix carbon fibers. By mixing carbon fiber, the tensile strength of the electrode is increased, and the electrode is less likely to crack or peel off. More preferably, it is more preferable to mix vapor growth carbon fiber. These materials can be used alone or in admixture of two or more. As a ratio of these materials in an electrode, 10-80 mass% is 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 A thickener may be used to facilitate the production of the electrode slurry. 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 In order to perform the electrode reaction more smoothly, a catalyst that assists the oxidation-reduction reaction can be used. 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. Further, 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 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. Preferably it is. 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 Conventionally known materials 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, N Organic solvents such as 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 present invention, a solid electrolyte can be used as the electrolyte. Polymer compounds used in these solid electrolytes 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 Polymers, acrylonitrile-methyl acrylate copolymer, acrylonitrile-ethyl methacrylate copolymer, acrylonitrile-ethyl acrylate copolymer, acrylonitrile-methacrylic acid copolymer, acrylonitrile-acrylic Acid copolymers, 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] Battery shape In the present invention, the shape of the battery is not particularly limited, and a conventionally known battery can be used. 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.

[9] Battery Manufacturing Method The battery manufacturing method is not particularly limited, and a method appropriately selected according to the material can be used. For example, a solvent is added to an electrode active material, a conductivity-imparting agent, etc. to form a slurry, which is applied to an electrode current collector, and the electrode is produced by heating or volatilizing the solvent at room temperature, and this electrode is sandwiched between a counter electrode and a separator. And then wrapped or wrapped in an outer package, and an electrolyte solution is injected and sealed. Solvents for slurrying include ether solvents such as tetrahydrofuran, diethyl ether, ethylene glycol dimethyl ether and dioxane; amine solvents such as N, N-dimethylformamide and N-methyl-2-pyrrolidone; benzene, toluene and xylene Aromatic hydrocarbon solvents such as hexane, heptane, etc .; Halogenated hydrocarbon solvents such as chloroform, dichloromethane, dichloroethane, trichloroethane, carbon tetrachloride; Alkyl ketone solvents such as acetone and methyl ethyl ketone Alcoholic solvents such as methanol, ethanol and isopropyl alcohol; dimethyl sulfoxide, water and the like. In addition, as a method for manufacturing an electrode, there is a method in which an electrode active material, a conductivity-imparting agent, and the like are kneaded in a dry method and then thinned and laminated on an electrode current collector. In the production of electrodes, in particular, in the case of a method in which a solvent is added to an organic electrode active material, a conductivity imparting agent, etc. and applied to an electrode current collector, and the solvent is volatilized by heating or at room temperature, peeling of the electrode, cracking, etc. Is likely to occur. When the polyradical compound of the present invention is used, and when an electrode having a thickness of preferably 40 μm or more and 300 μm or less is produced, the electrode has characteristics that the electrode is not easily peeled off or cracked and a uniform electrode can be produced. .

When manufacturing a battery, the battery is manufactured using the polymer that changes to the polyradical compound of the present invention by electrode reaction when the battery is manufactured using the polyradical compound of the present invention itself as an electrode active material. There are cases. Examples of the polymer that changes to the polyradical compound by such an electrode reaction include a lithium salt or sodium salt composed of an anion body obtained by reducing the polyradical compound and an electrolyte cation such as lithium ion or sodium ion, or the above-mentioned polyradical compound and a cation body oxidized PF ₆ ^- or BF ₄ ^-, etc. salt comprising the electrolyte anions such like.

  In the present invention, a conventionally known method can be used as a method for manufacturing a battery for other manufacturing conditions such as lead extraction from an electrode and outer packaging.

  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.

(Synthesis Example 1)
The following radical polymer (a) was synthesized. The synthesis method is shown below.

[1.1] Synthesis of 4-bromo-2,6-di-tert-butylphenol To a 3000 ml three-necked eggplant flask, 126 g (0.617 mol) of 2,6-di-tert-butylphenol and 220 ml of carbon tetrachloride were added. The mixture was stirred in an ice bath, and 107.4 g (0.674 ml, 1.1 eq) of bromine dissolved in 126 ml of carbon tetrachloride was added dropwise with a dropping funnel at such a rate that the color of bromine disappeared. After stirring for 5 minutes or more after dropping, unreacted bromine was treated with an aqueous sodium sulfite solution, and liquid separation extraction (chloroform / water), drying and recrystallization (hexane) gave 165.8 g of 4-bromo-tert-butylphenol ( 0.581 mol) was obtained as a white powder (yield 94.3%).

[1.2] Synthesis of (4-bromo-2,6-di-tert-butylphenoxy) trimethylsilane In a 2000 ml three-necked eggplant flask, 135.8 g (0.476 mol) of 4-bromo-tert-butylphenol and 270 ml of acetonitrile 106.3 g (0.523 mol) of N, O-bis (trimethylsilyl) acetamide was added with nitrogen flow, and the mixture was stirred overnight at 70 ° C. until crystals were completely precipitated. The precipitated crystals were filtered, dried and purified by recrystallization (ethanol) to obtain 150.0 g (0.420 mol) of (4-bromo-2,6-di-tert-butylphenoxy) trimethylsilane as white crystals. (Yield 88.1%).

[1.3] Synthesis of (p-bromophenyl) hydrogalvinoxyl 9.83 g (0.0275 mol) of (4-bromo-2,6-di-tert-butylphenoxy) trimethylsilane in a 500 ml three-necked eggplant flask After adding 200 ml of THF and stirring at −78 ° C. for 10 minutes, 15.8 ml of n-butyllithium (FW: 64.1, 0.025 mol, 5 eq) was added and stirred for 30 minutes to carry out a lithiation reaction. . After the reaction, 1.08 g (0.005 mol) of 4-bromobenzoate dissolved in 75 ml of THF was dropped and reacted at room temperature for 24 hours. A saturated aqueous ammonium chloride solution was added until the color change (dark blue → yellow) was completed, and after removing the solvent and liquid separation extraction (ether / water), the crude product was obtained as a yellow viscous liquid. The crude product was added to a 200 ml eggplant flask and dissolved in 10 ml of THF and 7.5 ml of methanol, and then 10N-HCl was gradually added until the color completely changed (yellow → red orange, several ml → 2 ml), and 30 minutes at room temperature. Then, the solvent was removed, followed by liquid separation extraction (ether / water). Purification by column chromatography (hexane / chloroform = 1/1) and recrystallization (hexane) gave 2.86 g (0.0049 mol) of (p-bromophenyl) hydrogalvinoxyl as orange crystals (yield) 99.1%).

[1.4] Synthesis of p-hydrogalvinoxylstyrene 2.100 g (p-bromophenyl) hydrogalvinoxyl (FW: 577.6, 4.33 mmol, 1 eq), 21.6 ml distilled toluene in a 100 ml eggplant flask And dissolved, 2.66-di-tert-butyl-p-cresol (FW: 220.4, 0.0216 mmol, 0.5 mmol%), tetrakis (triphenylphosphine) palladium catalyst 0.150 g ( FW: 1155.6, 0.130 mmol, 0.03 eq), 1.65 g of tributylvinyltin (FW: 317.1, 1.52 ml, 5.20 mmol, 1.2 eq) were added, and the atmosphere was replaced with nitrogen. And stirred for 17 hours. After the reaction, liquid separation extraction (ether / water), solvent removal, purification by flash column chromatography (hexane / chloroform = 1/3) and recrystallization (hexane), 1.54 g of p-hydrogalvinoxyl styrene (2.93 mmol) was obtained as orange crystals (yield 67.7%).
m. p. : 247.2 ° C;
MS (m / z): 525.8 calcd for MS = 524.8;
¹ H-NMR (CDCl ₃ , 500 MHz; ppm): δ 7.44 (d, 2H, J = 8.2 Hz, Ph), 7.24 (d, 2H, J = 8.2 Hz, Ph), 7.22 (S, 1H, Ph), 7.16 (s, 1H, Ph), 7.03 (s, 2H, Ph), 6.78 (dd, 1H, J = 18, 11 Hz, vinyl), 5.87 (D, 1H, J = 18 Hz, vinyl), 5.51 (s, 1H, OH), 5.36 (d, 1H, J = 11 Hz, vinyl), 1.41 (s, 18H, tert-butyl) , 1.27 (d, 18H, tert-butyl);
IR (liq, cm ⁻¹ ): 3629 (ν _OH ), 1594 (ν _C═O );
Anal. _{Calcd for C 37 H 48 O 2} : C, 84.7; H, 9.2. Found: C, 84.1; H, 9.8.

[1.5] Copolymerization of hydrogalvinoxyl styrene and tetraethylene glycol diacrylate Tetraethylene glycol from which 100 mg (0.191 mmol) of p-hydrogalvinoxyl styrene was removed in a 10 ml flask and the stabilizer (MEHQ) was removed by column purification 5.76 mg (0.0191 mmol) of diacrylate was dissolved in 1 ml (0.2 mol / l) of THF, and 1.73 mg (0.0105 mmol, 5 mol%) of azobisisobutyronitrile (AIBN) was added as an initiator. When heated and stirred at 70 ° C. for about 12 hours in a nitrogen atmosphere, a gel polymer was obtained. A poor solvent was added to the polymer, powdered using a mortar and ultrasonic stirring, and purified by Soxhlet (acetonitrile) extraction to obtain a copolymer copolymer (crosslinked poly (hydrogalvinoxyl styrene)) as an orange powder.

[1.6] Radical formation reaction by oxidation 30 mg of crosslinked poly (hydrogalvinoxyl styrene) and 30 ml of THF were added and dispersed, and oxidation was similarly performed with sodium hydroxide and potassium ferricyanide. The obtained polymer was washed with pure water and THF, filtered and dried to obtain a brown powder. From the ESR and SOUID measurements, it was confirmed that the hydroxyl group was converted to a radical at a rate of 90% to an oxy radical. In this way, radical polymer (a) was obtained.

Example 1
After the radical polymer (a) obtained in Synthesis Example 1 was pulverized in a mortar, 1.75 g of the radical polymer (a), 625 mg of carbon powder, 100 mg of carboxymethylcellulose (CMC), 25 mg of polytetrafluoroethylene (PTFE) and water 8 ml was stirred with a homogenizer to prepare a uniform slurry. This slurry was applied onto an aluminum foil (thickness 20 μm) with an electrode production coater, and further dried at 80 ° C. for 3 minutes to form an electrode layer having a thickness of 150 μm, which was used as a positive electrode.

Next, the obtained positive electrode was punched into a 30 × 30 mm square. A nickel lead having a length of 3 cm and a width of 0.5 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 30 × 30 mm square like the positive electrode to form a metal lithium negative electrode, and a nickel lead having a length of 3 cm and a width of 0.5 mm was welded to the copper foil surface. In this order, the positive electrode, the porous polypropylene separator (33 × 33 mm square), and the negative electrode were overlapped in the direction facing the radical positive electrode layer and the metal lithium negative electrode to form an electrode pair with nickel leads. Two pieces of aluminum laminate film (40 mm long × 40 mm wide × 0.76 mm thick) that can be heat-sealed were heat-sealed to form a bag-like case, and a pair of electrodes with nickel leads was inserted. 0.2 cc of an electrolytic solution [ethylene carbonate / diethyl carbonate mixed solution containing 1.0 mol / L LiPF ₆ electrolyte salt (mixing ratio 3: 7)] was added to the aluminum laminated case. The number of moles of LiPF ₆ electrolyte salt in the added electrolyte is about 1.25 times the number of moles of radicals.

  At this time, the end of the nickel lead of the electrode with the nickel lead was taken out by 1 cm, and one side of the aluminum laminate case that was not welded was heat-sealed. 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 40 mm × width 40 mm × thickness 0.4 mm) was produced. The battery was charged at 0.9 mA and then discharged at a constant current of 0.9 mA. As a result, discharge was performed at an average voltage of 3.5 V for 4 hours and 30 minutes. The discharge capacity density per active material was 66.4 mAh / g. Since the discharge capacity density when all radicals are involved in charge / discharge is 67.2 mAh / g, 99% of radicals are involved in charge / discharge.

(Comparative Example 1)
A battery was fabricated in the same manner as in Example 1, except that the following radical polymer (b) (number average molecular weight: 27000) was used instead of using the radical polymer (a). However, the amount of the electrolytic solution was 0.35 ml. The number of moles of LiPF ₆ electrolyte salt in the added electrolyte is about 1.25 times the number of moles of radicals. As a result of charging and discharging the manufactured battery in the same manner as in Example 1, the voltage became substantially constant for 45 minutes near 3.5 V, and then dropped rapidly. The discharge capacity per electrode active material was 32 mAh / g. Since the discharge capacity density when all radicals are involved in charge / discharge is 111 mAh / g, the ratio of radicals involved in charge / discharge is 28.8%.

(Comparative Example 2)
A battery was prepared in the same manner as in Example 1, except that the radical polymer (b) was used instead of the radical polymer (a). However, the amount of the electrolyte was 1.1 ml. The number of moles of LiPF ₆ electrolyte salt in the added electrolyte is about 4 times the number of moles of radicals. As a result of charging and discharging the produced battery in the same manner as in Example 1, the voltage became almost constant for 7 hours near 3.5 V, and then dropped rapidly. The discharge capacity per electrode active material was 105 mAh / g. Since the discharge capacity density when all radicals are involved in charge / discharge is 111 mAh / g, the ratio of radicals involved in charge / discharge is 95%.

It is a schematic diagram which shows the structure of one Embodiment of the battery of this invention. It is a perspective view of one embodiment of the battery of the present invention.

Explanation of symbols

11 Positive electrode 12 Separator 13 Negative electrode 14 + Tab 15 -Tab 16 Exterior film

Claims (8)

The polyradical compound which has a structure bridge | crosslinked by the polyfunctional crosslinking agent which has a repeating structural unit represented by following formula (1), and has two or more polymeric groups in a molecule | numerator.

The polyradical compound according to claim 1, wherein the crosslinking agent is a compound represented by the following general formula (2a).

(In General Formula (2a), X represents a linear, branched or cyclic alkylenedioxy group having 1 to 12 carbon atoms, or a structure represented by General Formula (3). R ¹ is independently a hydrogen atom. Or represents a methyl group.)

(In general formula (3), k represents an integer of 2 to 8.) The polyradical compound according to claim 1, wherein the structure crosslinked by the crosslinking agent is a structure represented by the following general formula (2b).

(In General Formula (2b), X represents a linear, branched or cyclic alkylenedioxy group having 1 to 12 carbon atoms, or a structure represented by General Formula (3). R ¹ is independently a hydrogen atom. Or represents a methyl group.)

(In general formula (3), k represents an integer of 2 to 8.)   The polyradical compound according to any one of claims 1 to 3, wherein the molar ratio of the repeating structural unit represented by the general formula (1) and the structure crosslinked by the crosslinking agent is 10: 1 to 1000: 1. .   In a battery comprising at least a positive electrode, a negative electrode, and an electrolyte, the polyradical compound according to any one of claims 1 to 4 is used as an electrode active material of at least one of the positive electrode and the negative electrode. Battery to play.   The battery according to claim 5, wherein the polyradical compound is used as at least a positive electrode active material.   The battery according to claim 5 or 6, which is a lithium battery.   The battery according to claim 7, which is a lithium secondary battery.

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