JP2009126869A - Nitroxide polymer and battery using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a nitroxide polymer usable as an electrode material for a battery of which a large current can be taken out and from which the reduction of a capacity is little even when the discharge and charge are carried out repeatedly, to provide an electrode active material containing the polymer, and to provide a battery using the electrode active material. <P>SOLUTION: The nitroxide polymer is obtained by polymerizing 2,2,6,6-tetramethyl-3,4-epoxypiperidin-1-oxyl represented by formula (1). The electrode active material contains the polymer. The battery uses the electrode active material. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a nitroxide polymer, an electrode active material containing the polymer, and a battery using the electrode active material.

  With the rapid market expansion of notebook personal computers and mobile phones, there is an increasing demand for small high-capacity secondary batteries with high energy density used for these. In order to meet this demand, a secondary battery using an alkali metal ion such as lithium ion as a charge carrier and utilizing an electrochemical reaction accompanying charge transfer has been developed. Among these, lithium ion secondary batteries are used in various electronic devices as high-capacity secondary batteries having high energy density and excellent stability. Such a lithium ion secondary battery generally uses a lithium-containing transition metal oxide as a positive electrode as an active material and carbon as a negative electrode, and utilizes insertion and desorption reactions of lithium ions into these active materials. Charging and discharging.

In recent years, secondary batteries utilizing radical compounds as electrode active materials that directly contribute to electrode reactions have been proposed for the purpose of increasing capacity. Patent Document 1 discloses a secondary battery including a radical compound as an active material of at least one of a positive electrode and a negative electrode. Patent Document 2 discloses an electricity storage device containing a nitroxyl compound in a positive electrode. In such an electricity storage device, it is said that charging and discharging can be performed with a large current due to a fast electrode reaction.
JP 2002-151084 A JP 2002-304996 A

  However, a secondary battery in which at least one of the positive electrode and the negative electrode active material described in Patent Document 1 contains a radical compound, and an electricity storage device using a nitroxyl compound containing a stable radical described in Patent Document 2 However, there was room for improvement in terms of capacity reduction after repeated charge and discharge.

  The present invention provides a nitroxide polymer that can be used as an electrode material for a battery that can take out a large current and has little decrease in capacity even after repeated charging and discharging, an electrode active material containing the polymer, and the electrode active material. An object is to provide a battery using a substance.

  The present invention relates to formula (1):

で表される２，２，６，６−テトラメチル−３，４−エポキシピペリジン−１−オキシルを重合して得られるニトロキシド重合体に関する。
また、本発明は、前記ニトロキシド重合体を含有する電極活物質に関する。
さらに、本発明は、前記電極活物質を用いた電池に関する。

And a nitroxide polymer obtained by polymerizing 2,2,6,6-tetramethyl-3,4-epoxypiperidine-1-oxyl represented by formula (1).
The present invention also relates to an electrode active material containing the nitroxide polymer.
Furthermore, the present invention relates to a battery using the electrode active material.

The present invention is described in detail below.
The nitroxide polymer according to the present invention is obtained by polymerizing 2,2,6,6-tetramethyl-3,4-epoxypiperidine-1-oxyl represented by the following formula (1).

  2,2,6,6-tetramethyl-3,4-epoxypiperidine-1-oxyl represented by the formula (1) is, for example, 2,2,6,6-tetramethyl as shown in the following formula It can be produced by a method using a -4-piperidone compound (Bull. Acad. Sci. USSR Div. Chem. Sci. (Engl. Transl.); EN; 31; 2; 1982; 401-404). Specifically, 2,2,6,6-tetramethyl-4-oxopiperidine hydrochloride is halogenated using sulfuryl chloride or the like to produce 2,2,6,6-tetramethyl-3-chloro-4-oxo. Piperidine, then oxidized with metachloroperbenzoic acid or the like to give 2,2,6,6-tetramethyl-3-chloro-4-oxopiperidine-1-oxyl, then hydrogenated This is reduced with sodium boron or the like to obtain 2,2,6,6-tetramethyl-3-chloro-4-hydroxypiperidine-1-oxyl, and further epoxidized with sodium hydroxide or the like. Thus, 2,2,6,6-tetramethyl-3,4-epoxypiperidine-1-oxyl represented by the formula (1) can be produced.

  The nitroxide polymer according to the present invention is obtained by polymerizing the 2,2,6,6-tetramethyl-3,4-epoxypiperidine-1-oxyl.

  The method for polymerizing 2,2,6,6-tetramethyl-3,4-epoxypiperidine-1-oxyl is not particularly limited. For example, polymerization may be performed using a bulk polymerization method, a solution polymerization method, or the like. The method of doing can be mentioned.

  Examples of the polymerization method using the bulk polymerization method include using a reactor equipped with a stirrer, a thermometer, a gas introduction pipe for introducing an inert gas such as argon gas or nitrogen gas, and a cooling pipe. And a method in which a predetermined amount of 2,2,6,6-tetramethyl-3,4-epoxypiperidine-1-oxyl is charged, deoxygenated with an inert gas, and then a polymerization initiator is added with stirring. .

  As a method of polymerizing using the solution polymerization method, for example, when polymerizing using the bulk polymerization method, a predetermined amount of 2,2,6,6-tetramethyl-3,4-epoxypiperidine-1- There is a method in which an inert solvent is charged together with oxyl, deoxygenated with an inert gas, and then a polymerization initiator is added with stirring.

  Examples of the inert solvent used for polymerization using the solution polymerization method include aromatic hydrocarbon solvents such as benzene, toluene and xylene; acyclic saturation such as n-hexane, n-heptane and ligroin Hydrocarbon solvents; cyclic saturated hydrocarbon solvents such as cyclopentane, methylcyclopentane, cyclohexane and methylcyclohexane; and inert solvents such as ether solvents such as diethyl ether and tetrahydrofuran. Among these, aromatic hydrocarbon solvents and acyclic saturated hydrocarbon solvents are preferred from the viewpoint of being easily available industrially, inexpensive, and stabilizing the quality of the resulting polymerization reaction product. And n-hexane are preferably used.

  The amount of the inert solvent used in the polymerization using the solution polymerization method is not particularly limited. However, from the viewpoint of allowing the reaction to proceed smoothly and obtaining an effect that is commensurate with the amount used, 2 1,2,6,6-tetramethyl-3,4-epoxypiperidine-1-oxyl is preferably 1 to 2000 parts by weight based on 100 parts by weight.

  It does not specifically limit as said polymerization initiator, For example, it can superpose | polymerize using an anionic polymerization initiator. Examples of the anionic polymerization initiator include tert-butoxy potassium, Grignard reagent (n-butylmagnesium bromide, isobutylmagnesium bromide, tert-butylmagnesium bromide, n-butylmagnesium chloride, isobutylmagnesium chloride, tert-butylmagnesium chloride, etc. ), Alkyllithium (n-butyllithium, tert-butyllithium, 1,1, -diphenylhexyllithium, etc.), diethylzinc and diethylzinc / water-based initiator. Among these, tert-butoxy potassium, diethyl zinc, and diethyl zinc / water initiator are preferably used from the viewpoint of stabilizing the quality of the obtained polymerization reaction product.

  The amount of the polymerization initiator used varies depending on the type of polymerization initiator used and the reaction temperature, but is usually 100 parts by weight of 2,2,6,6-tetramethyl-3,4-epoxypiperidine-1-oxyl. The amount is preferably 0.05 to 20 parts by weight. In the polymerization reaction, additives such as a chain transfer agent such as isopropyl alcohol and a polymerization terminator such as methanol may be added as necessary.

  As reaction temperature, although it changes with kinds of polymerization initiator to be used, -100-100 degreeC is preferable normally and -50-80 degreeC is more preferable. Although the reaction time varies depending on the reaction temperature, it cannot be generally stated, but it is usually 5 to 40 hours.

  The nitroxide polymer thus obtained can be isolated, for example, by mixing the reaction liquid with a solvent such as aliphatic hydrocarbon such as hexane to precipitate the polymerization reaction product and then filtering. Furthermore, it can be purified by removing and washing unreacted substances using methanol, hexane or the like, and removing, washing and drying the polymerization initiator residue using dilute hydrochloric acid, water or the like.

  The nitroxide polymer according to the present invention may have a crosslinked structure. The nitroxide polymer having a cross-linked structure may be copolymerized by adding a cross-linking agent when polymerizing the 2,2,6,6-tetramethyl-3,4-epoxypiperidine-1-oxyl, for example. Can be manufactured.

  The crosslinking agent is not particularly limited as long as it is a compound having a plurality of polymerizable unsaturated groups in the molecule. For example, 1,2,3,4-diepoxybutane, 1,2,4,5- Diepoxypentane, 1,2,5,6-diepoxyhexane, 1,2,6,7-diepoxyheptane, 1,2,7,8-diepoxyoctane, 1,2,8,9-diepoxy Nonane, 1,2,9,10-diepoxydecane and the like can be mentioned. Among these, 1,2,7,8-diepoxyoctane, 1,2,8,9-diepoxynonane and 1,2,9,10-diepoxydecane are preferable from the viewpoint of high polymerization reactivity. Used for. In addition, these crosslinking agents may be used individually by 1 type, respectively, or may use 2 or more types together.

  The use ratio of the crosslinking agent is not particularly limited, but is 0.00001 to 0.25 with respect to 1 mole of 2,2,6,6-tetramethyl-3,4-epoxypiperidine-1-oxyl. The molar ratio is preferably 0.00005 to 0.1 mol, and more preferably 0.0001 to 0.05 mol.

  The number average molecular weight of the nitroxide polymer according to the present invention is preferably 500 to 10000000, and more preferably 1000 to 1000000. If it is less than 500, the nitroxide polymer dissolves in the electrolytic solution, which may reduce the capacity of the battery using the electrode active material containing the nitroxide polymer. If it exceeds 10000000, handling becomes difficult. There is a risk. In addition, the said number average molecular weight means the standard polystyrene conversion value measured by the gel permeation chromatography method.

  The electrode active material according to the present invention contains the nitroxide polymer according to the present invention. Such an electrode active material is also one aspect of the present invention.

  The battery according to the present invention uses the electrode active material according to the present invention. Such a battery is also one aspect of the present invention.

  FIG. 1 shows an example of an embodiment of a battery according to the present invention. The battery shown in FIG. 1 has a configuration in which a positive electrode 5 and a negative electrode 3 are superposed so as to face each other via a separator 4 containing an electrolyte, and a positive electrode current collector 6 is superposed on the positive electrode 5. . These are covered with a stainless steel outer sheath 1 on the negative electrode side and a stainless steel outer sheath 1 on the positive electrode side, and an insulating packing 2 made of an insulating material such as a plastic resin is disposed between them for the purpose of preventing electrical contact between them. Yes. In addition, when using solid electrolyte and gel electrolyte as electrolyte, it can replace with the separator 4 containing electrolyte, and can also be set as the form which interposes these electrolytes between electrodes.

  The electrode active material according to the present invention can be used for the negative electrode 3, the positive electrode 5, or both electrodes in such a battery. In addition, the battery according to the present invention uses the electrode active material according to the present invention as the electrode active material of the negative electrode 3, the positive electrode 5, or both electrodes.

  Below, the main members etc. which comprise a battery are demonstrated.

(1) Electrode Active Material In the present invention, “electrode active material” refers to a material that directly contributes to electrode reactions such as charge reaction and discharge reaction, and plays a central role in the battery system.

  The electrode active material according to the present invention contains the nitroxide polymer according to the present invention, and each of the nitroxide polymers according to the present invention may be used alone as the positive electrode and / or negative electrode active material. Also, an electrode active material may be combined with other electrode active materials.

  When the nitroxide polymer according to the present invention is used as a positive electrode active material, examples of other electrode active materials include metal oxides, disulfide compounds, other stable radical compounds, and conductive polymers.

Examples of the metal oxide include lithium manganate such as LiMnO ₂ and Li _x Mn ₂ O ₄ (0 <x <2), lithium manganate having a spinel structure, MnO ₂ , LiCoO ₂ , LiNiO ₂ , or Li _y V ₂ O ₅ (0 <y <2), olivine-based material LiFePO ₄ , materials obtained by substituting a part of Mn in the spinel structure with other transition metals, 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 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 the other stable radical compound include poly (2,2,6,6-tetramethylpiperidinoxyl-4-yl methacrylate).

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

Among these, lithium manganate and LiCoO ₂ are preferably used. These other electrode active materials may be used alone or in combination with two or more of the nitroxide polymers.

  When the nitroxide polymer is used as an electrode active material for a negative electrode, other electrode active materials include graphite, amorphous carbon, metallic lithium and lithium alloy, lithium ion storage carbon, metallic sodium, other stable radical compounds, and conductive materials. Can be mentioned.

  Other stable radical compounds include poly (2,2,6,6-tetramethylpiperidinoxyl-4-yl methacrylate) and the like.

  Among these, it is preferable to combine with metallic lithium or graphite. In addition, it does not specifically limit as these shapes, A thin-film thing, a bulk thing, the thing which hardened the powder, a fibrous thing, a flake-like thing, etc. may be sufficient. These other electrode active materials may be used alone or in combination with two or more of the nitroxide polymers.

  In the battery according to the present invention, the electrode active material containing the nitroxide polymer according to the present invention is used as the electrode active material of one of the positive electrode and the negative electrode, or both electrodes. In the case of using an electrode active material containing a coalescence, a conventionally known electrode active material exemplified as the other electrode active material can be used as the electrode active material in the other electrode.

  In the present invention, from the viewpoint of energy density, the electrode active material containing the nitroxide polymer is preferably used as a positive electrode active material, and the nitroxide polymer is used alone without being combined with the other electrode active materials. Is more preferable. Moreover, it is preferable to use metallic lithium or graphite as the electrode active material of the negative electrode at this time.

(2) Conductivity-imparting agent (auxiliary conductive material) and ion conduction auxiliary material When the electrode active material according to the present invention is used as an electrode active material for a positive electrode, for the purpose of reducing impedance and improving energy density and output characteristics, A conductivity imparting agent (auxiliary conductive material) or an ion conduction auxiliary material may be mixed.

  Examples of the auxiliary conductive material include carbonaceous fine particles such as graphite, carbon black, and acetylene black, carbon fibers such as vapor grown carbon fiber (VGCF) and carbon nanotube, polyaniline, polypyrrole, polythiophene, polyacetylene, and polyacene. Molecule.

  Examples of the ion conduction auxiliary material include polymer gel electrolytes and polymer solid electrolytes. Among these, carbon fibers are preferably used, and vapor-grown carbon fibers are more preferably used. By using carbon fiber, the tensile strength of the electrode is increased, and the electrode is less likely to crack or peel off. These auxiliary conductive materials and ion conductive auxiliary materials may be used alone or in combination of two or more.

  When the auxiliary conductive material or the ion conductive auxiliary material is used, the mixing ratio in the electrode is preferably 10 to 80% by weight.

(3) Binder In the electrode active material according to the present invention, a binder may be mixed in order to strengthen the connection between the constituent materials.

  Examples of the binder include polytetrafluoroethylene, polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-tetrafluoroethylene copolymer, styrene / butadiene copolymer rubber, polypropylene, polyethylene, and polyimide. And resin binders such as various polyurethanes. These binders may be used individually by 1 type, or may use 2 or more types together.

  When the binder is used, the mixing ratio in the electrode is preferably 5 to 30% by weight.

(4) Thickener In order to make it easy to produce a slurry for forming the electrode active material according to the present invention, a thickener may be mixed.

  Examples of the thickener include carboxymethyl cellulose, polyethylene oxide, polypropylene oxide, hydroxyethyl cellulose, hydroxypropyl cellulose, carboxymethyl hydroxyethyl cellulose, polyvinyl alcohol, polyacrylamide, polyethyl acrylate, ammonium polyacrylate, and sodium polyacrylate. Is mentioned. These thickeners may be used individually by 1 type, or may use 2 or more types together.

  When the thickener is used, the mixing ratio in the electrode is preferably 0.1 to 5% by weight.

(5) Catalyst In the electrode active material according to the present invention, a catalyst that assists the oxidation-reduction reaction may be mixed in order to perform the electrode reaction more smoothly.

  Examples of the catalyst 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. . These catalysts may be used individually by 1 type, or may use 2 or more types together.

  When the catalyst is used, the mixing ratio in the electrode is preferably 10% by weight or less.

(6) Current collector and separator Examples of the current collector used in contact with the electrode active material according to the present invention include nickel, aluminum, copper, gold, silver, aluminum alloy, stainless steel, carbon, foil, A metal flat plate or mesh shape 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, examples of the separator include porous films and nonwoven fabrics made of polyethylene, polypropylene, and the like.

(7) Electrolyte In the battery according to 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 ) Conventionally known materials such as ₃ C and Li (C ₂ F ₅ SO ₂ ) ₃ C can be mentioned. These electrolyte salts may be used individually by 1 type, or may use 2 or more types together.

  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-dimethylacetamide, N-methyl. An organic solvent such as -2-pyrrolidone can be mentioned. These solvents may be used alone or in combination of two or more.

  Further, as the electrolyte, a solid electrolyte in which the electrolyte salt is contained in a polymer compound or a solid electrolyte in which the electrolyte solution is contained in a polymer compound to form a gel can be used.

  Examples of the polymer compound include polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-ethylene copolymer, vinylidene fluoride-monofluoroethylene copolymer, and vinylidene fluoride-trifluoroethylene copolymer. Polymers, vinylidene fluoride-tetrafluoroethylene copolymers, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymers and other vinylidene fluoride polymers, acrylonitrile-methyl methacrylate copolymers, acrylonitrile- Methyl acrylate copolymer, acrylonitrile-ethyl methacrylate copolymer, acrylonitrile-ethyl acrylate copolymer, acrylonitrile-methacrylic acid copolymer, acrylonitrile-acrylic acid copolymer, acrylo Tolyl - vinyl acetate copolymer, acrylonitrile-based polymer, further polyethylene oxide, ethylene oxide - propylene oxide copolymer, polymer and the like of these acrylates body or methacrylate products thereof.

(8) Battery shape The shape of the battery according to the present invention is not particularly limited, and conventionally known batteries can be used. For example, an electrode laminate or a wound body is sealed with a metal case, a resin case, or a laminate film composed of a metal foil such as an aluminum foil and a synthetic resin film, etc. Examples include molds and sheet molds.

(9) Battery Manufacturing Method The battery manufacturing method according to the present invention is not particularly limited, and a method appropriately selected according to the material can be used. For example, a solvent is added to the electrode active material, the conductivity-imparting agent, etc. according to the present invention to form a slurry, which is applied to the electrode current collector, and the electrode is produced by heating or volatilizing the solvent at room temperature. In this method, the separators are stacked or wound, wrapped with an outer package, and injected with an electrolyte solution to be 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, methyl ethyl ketone, etc. , Alcohol solvents such as methanol, ethanol and isopropyl alcohol, dimethyl sulfoxide, water and the like. In addition, as an electrode manufacturing method, there is a method in which an electrode active material, a conductivity-imparting agent, and the like are kneaded in a dry manner and then thinned and laminated on an electrode current collector.

In the method for producing a battery according to the present invention, there are a case where the nitroxide polymer itself is used as a compound constituting the electrode active material and a case where a polymer which changes to the nitroxide polymer by an electrode reaction is used. Examples of the polymer that changes to the nitroxide polymer by such an electrode reaction include a lithium salt or sodium salt composed of an anion body obtained by reducing the nitroxide polymer and an electrolyte cation such as lithium ion or sodium ion, and a cation body oxidizing the nitroxide polymer, PF ₆ ^- and BF ₄ ^- salts consisting of an electrolyte anions such.

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

  According to the present invention, a nitroxide polymer that can be used as an electrode material for a battery that can extract a large current and has little reduction in capacity even after repeated charge and discharge, an electrode active material containing the polymer, and the electrode A battery using an active material can be provided.

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

Production Example 1 (Production of 2,2,6,6-tetramethyl-3,4-epoxypiperidine-1-oxyl)
A 200 mL four-necked flask equipped with a stirrer, a thermometer and a reflux condenser was charged with 6.91 g (36 mmol) of 2,2,6,6-tetramethyl-4-oxopiperidine hydrochloride and 120 mL of methylene chloride. , Dissolved. Next, the mixture was cooled to 5 ° C., and 5.00 g (37 mmol) of sulfuryl chloride was added dropwise with stirring. After stirring for 4 hours, the solvent was distilled off under reduced pressure to obtain a solid. The solid obtained was washed with 60 mL of 10% by weight aqueous sodium hydrogen carbonate solution and dried to give 5.46 g of 2,2,6,6-tetramethyl-3-chloro-4-oxopiperidine (yield 80 %).

The obtained 2,2,6,6-tetramethyl-3-chloro-4-oxopiperidine could be identified from the following physical properties.
IR (KBr): 3325, 1745, 1715 cm ⁻¹
Molecular weight (mass spectrometry by atmospheric pressure ionization method): 190

  Next, the obtained 2,2,6,6-tetramethyl-3-chloro-4-oxopiperidine (4.74 g, 25 mmol) and methyl chloride (75 mL) were mixed with a stirrer, an argon gas introduction tube, a thermometer, and reflux cooling. A 200 mL 4-neck flask equipped with a tube and previously substituted with argon gas was charged and dissolved. Next, 8.63 g (50 mL) of metachloroperbenzoic acid / 25 mL of methylene chloride was added, and the mixture was stirred at 25 ° C. for 8 hours, followed by filtration under reduced pressure. After washing, the solution was concentrated and dried to obtain 4.61 g (22.5 mmol) of 2,2,6,6-tetramethyl-3-chloro-4-oxopiperidine-1-oxyl.

The obtained 2,2,6,6-tetramethyl-3-chloro-4-oxopiperidine-1-oxyl could be identified from the following physical properties.
IR (KBr): 1740 cm ⁻¹
Molecular weight (mass spectrometry by atmospheric pressure ionization method): 205

  Next, 4.09 g (20 mmol) of the obtained 2,2,6,6-tetramethyl-3-chloro-4-oxopiperidine-1-oxyl and 50 ml of methanol were equipped with a stirrer, thermometer and reflux condenser. Into a 200 mL four-necked flask, it was dissolved. Next, 0.83 g (22 mmol) of sodium borohydride was added and stirred at 25 ° C. for 4 hours, and then the solvent was distilled off under reduced pressure to obtain a solid. After adding 10 g of pure water to the obtained solid content and dissolving it, liquid separation was performed using 100 mL of diethyl ether, and the diethyl ether layer was concentrated and dried to give 2,2,6,6-tetramethyl-3- Chloro-4-hydroxypiperidine-1-oxyl 3.84 g (18.6 mmol) was obtained.

The obtained 2,2,6,6-tetramethyl-3-chloro-4-hydroxypiperidine-1-oxyl could be identified from the following physical properties.
IR (KBr): 3590 cm ⁻¹
Molecular weight (mass spectrometry by atmospheric pressure ionization method): 207

  An aqueous sodium hydroxide solution (0.70 g, 17.5 mmol) and pure water (50 mL) were charged into a 100 mL four-necked flask equipped with a stirrer, thermometer, and reflux condenser and dissolved. To this was added 3.10 g (15 mmol) of 2,2,6,6-tetramethyl-3-chloro-4-hydroxypiperidine-1-oxyl, and the mixture was stirred at 25 ° C. for 4 hours. Thereafter, the mixture was separated using 150 mL of diethyl ether, and the diethyl ether layer was concentrated and dried to obtain 2.81 g (16.5 mmol) of 2,2,6,6-tetramethyl-3,4-epoxypiperidine-1-oxyl. )

The obtained 2,2,6,6-tetramethyl-3,4-epoxypiperidine-1-oxyl could be identified from the following physical properties.
IR (KBr): 1260,1087 cm ⁻¹
Molecular weight (mass spectrometry by atmospheric pressure ionization method): 170

Example 1 (Production of nitroxide polymer)
2,2,6,6-tetramethyl-3,4 obtained in the same manner as in Production Example 1 was added to a 50 mL four-necked flask equipped with a stirrer, an argon gas inlet tube, a thermometer, and a reflux condenser. -1.70 g (10 mmol) of epoxypiperidine-1-oxyl and 5 mL (4.325 g) of toluene were charged, and oxygen in the reaction system was removed through argon gas while maintaining at 25 ° C. Next, 11.2 mg (0.10 mmol) of tert-butoxy potassium as a polymerization initiator was added, the temperature was raised to 60 ° C. under an argon gas atmosphere, and the polymerization reaction was carried out at the same temperature for 24 hours with stirring. Of methanol was added to stop the reaction. After completion of the reaction, the reaction solution was returned to room temperature, added to 100 mL of hexane, filtered, washed with 20 mL of hexane, and dried under reduced pressure to obtain 0.60 g of an amber solid nitroxide polymer (yield 35). %).

  It was 7700 when the number average molecular weight was measured about the obtained nitroxide polymer. The number average molecular weight is 30 ° C in N, N-dimethylformamide containing LiBr (0.01 mol / L) using gel permeation chromatography (trade name: HLC-8020, manufactured by Tosoh Corporation). Measured and calculated with reference to standard polystyrene.

Example 2 (Production of nitroxide polymer)
2,2,6,6-tetramethyl-3,4 obtained in the same manner as in Production Example 1 was added to a 50 mL four-necked flask equipped with a stirrer, an argon gas inlet tube, a thermometer, and a reflux condenser. -1.70 g (10 mmol) of epoxypiperidine-1-oxyl and 5 mL (4.325 g) of toluene were charged, and oxygen in the reaction system was removed through argon gas while maintaining at 25 ° C. Next, 0.1 mL of a 1 mol / L hexane solution of diethyl zinc as a polymerization initiator (diethyl zinc 12.5 mg) was added and a polymerization reaction was performed at 25 ° C. for 24 hours, and then an appropriate amount of methanol was added to react. Was stopped. After completion of the reaction, the reaction solution was added to 100 mL of hexane, filtered, washed with 20 mL of hexane, and dried under reduced pressure to obtain 1.45 g of an amber solid nitroxide polymer (yield 85%).

  It was 9800 when the number average molecular weight was measured about the obtained nitroxide polymer. The number average molecular weight is 30 ° C in N, N-dimethylformamide containing LiBr (0.01 mol / L) using gel permeation chromatography (trade name: HLC-8020, manufactured by Tosoh Corporation). Measured and calculated with reference to standard polystyrene.

Example 3 (Production of nitroxide polymer)
In Example 2, 1.62 g of an amber solid nitroxide polymer was obtained in the same manner as in Example 2 except that the polymerization temperature was changed to 60 ° C. instead of the polymerization temperature of 25 ° C. (yield 95%).

  It was 8100 when the number average molecular weight was measured about the obtained nitroxide polymer. The number average molecular weight is 30 ° C in N, N-dimethylformamide containing LiBr (0.01 mol / L) using gel permeation chromatography (trade name: HLC-8020, manufactured by Tosoh Corporation). Measured and calculated with reference to standard polystyrene.

Example 4 (Battery using an electrode active material containing a nitroxide polymer)
0.01 g of the nitroxide polymer obtained in Example 2, 0.08 g of graphite powder as an auxiliary conductive material, and 0.01 g of polytetrafluoroethylene as a binder were weighed and kneaded using an agate mortar. The mixture obtained by dry-mixing for about 10 minutes was subjected to roller stretching under pressure to obtain a thin film having a thickness of about 150 μm. This was dried overnight at 100 ° C. in a vacuum and then punched into a circle having a diameter of 12 mm to form a coin battery electrode. The mass of this electrode was 12.9 mg.

Next, the obtained electrode was immersed in an electrolytic solution, and the electrolytic solution was infiltrated into voids in the electrode. As the electrolytic solution, an ethylene carbonate / diethyl carbonate mixed solution (mixing volume ratio 1: 1) containing 1.0 mol / L LiPF ₆ electrolyte salt was used. The electrode impregnated with the electrolytic solution was placed on a stainless steel sheath (manufactured by Kagatsu Co., Ltd.) that also served as a positive electrode current collector, and a polypropylene porous film separator that was also impregnated with the electrolytic solution was laminated thereon. Furthermore, the lithium disk used as a negative electrode was laminated | stacked, and the negative electrode side stainless steel exterior (made by Kagatsu Co., Ltd.) was piled up in the state which has arrange | positioned the insulating packing around. By applying pressure with a caulking machine, a sealed coin-type battery using the nitroxide polymer obtained in Example 2 as the positive electrode active material and metallic lithium as the negative electrode active material was produced.

When a cyclic voltammogram was measured for this coin-type battery in a potential sweep range of 3.2 to 4.2 V, a redox wave derived from the p-type redox of the nitroxide radical appeared at 3.65 V, and it was oxidized even after repeated sweeps. The reduction wave was stable. Further, when a charge / discharge curve at a constant current of 0.1 mA (current density of 150 μA / cm ² ) was measured, a plateau potential appeared at 3.64 V, and no significant decrease in capacity was observed even after 500 cycles, and stable charge and discharge were observed. The discharge behavior was shown.

It is a conceptual diagram which shows an example of embodiment of the battery which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Stainless steel exterior 2 Insulation packing 3 Negative electrode 4 Separator 5 Positive electrode 6 Positive electrode collector

Claims (3)

Formula (1):

A nitroxide polymer obtained by polymerizing 2,2,6,6-tetramethyl-3,4-epoxypiperidine-1-oxyl represented by the formula:   An electrode active material containing the nitroxide polymer according to claim 1.   A battery using the electrode active material according to claim 2.

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