JP5176130B2 - Polyradical compounds, electrode active materials and batteries - Google Patents

Description

  The present invention relates to an electrode active material capable of taking out a large current, a battery capable of producing a large output and having little decrease in capacity even after repeated charge and discharge, and an electrode active material having the above-described characteristics. The present invention relates to a polyradical compound that can be a substance.

  With the rapid market expansion of notebook PCs, mobile phones, electric cars, etc., high output power storage devices are required. Among them, lithium ion secondary batteries using a lithium-containing transition metal oxide for the positive electrode and a carbon material for the negative electrode are used in various portable devices as high energy density batteries having excellent charge / discharge characteristics.

Patent Document 1 discloses a secondary battery in which at least one active material of a positive electrode and a negative electrode contains a radical compound. Patent Document 2 discloses an electricity storage device containing a nitroxyl compound in a positive electrode. This electricity storage device is said to be able to charge and discharge with a large current because of its fast electrode reaction.
Japanese Patent No. 3687736 JP 2002-304996 A

  However, the lithium ion secondary battery cannot be said to have a high reaction rate of the electrode reaction, and the capacity may be significantly reduced when a large current is passed. In addition, 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 It is said that charging and discharging can be performed with a large current because of the fast electrode reaction, but there is room for improvement in capacity reduction after repeated charging and discharging.

  The present invention relates to an electrode active material capable of taking out a large current, a battery capable of producing a large output and having little decrease in capacity even after repeated charge and discharge, and an electrode active material having the above-described characteristics. The object is to provide a polyradical compound that can be a substance.

  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 general formula (1) in the molecule, and the general formula It has been found that the above problem can be solved by using a polyradical compound crosslinked by the structure represented by (2) as an electrode active material. That is, according to the present invention, a large battery can be produced (more specifically, a large current can be discharged) by using a redox battery utilizing the oxidation-reduction of the polyradical compound, and repeated charge / discharge. Thus, a novel battery with little decrease in capacity can be provided.

  The present invention is a polyradical compound having a repeating structural unit represented by the general formula (1) and crosslinked by a structure represented by the general formula (2). In addition, the present invention is characterized in that at least an electrode active material used for at least one of the positive electrode and the negative electrode of a battery having a positive electrode, a negative electrode, and an electrolyte as a constituent element contains the polyradical compound of the present invention. Electrode active material. Furthermore, the present invention is a battery comprising at least one of a positive electrode, a negative electrode, and an electrolyte, wherein the electrode active material of the present invention is used for at least one of the positive electrode and the negative electrode.

(In General formula (1), R < ¹ > -R < ³ > is respectively independently a hydrogen atom or a methyl group, R < ⁴ > -R < ⁵ > is respectively independently a hydrogen atom or a C1-C3 alkyl group, R < ⁶ > -R < ⁹ >. Each independently represents an alkyl group having 1 to 3 carbon atoms.)

(In the general formula (2), X represents a linear, branched, or cyclic alkylene group having 1 to 12 carbon atoms, or a linear, branched, or cyclic alkylenedioxy group, or phenylene group, or phenylene group having 1 to 12 carbon atoms. An oxy group or a divalent structure represented by the general formula (3) is shown. R ^{10 to} R ¹⁵ each independently represent a hydrogen atom or a methyl group.)

(In General Formula (3), Y represents a linear, branched, cyclic alkylene group, or phenylene group having 1 to 12 carbon atoms, or a divalent structure represented by General Formula (4) or General Formula (5). R ^{16 to} R ¹⁹ each independently represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.)

(In general formula (4), n represents an integer of 1 to 10.)

(In General Formula (5), Z represents a linear, branched, or cyclic alkylene group having 1 to 12 carbon atoms or an oxygen atom. M represents an integer of 1 to 10.)
In the present invention, a polyradical compound having a repeating structural unit represented by the general formula (1) in the molecule and crosslinked by the structure represented by the general formula (2) is excellent as an electrode active material. It was made based on the finding. This is because the polyradical compound causes a reversible and stable oxidation-reduction reaction at a rate of almost 100% with 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. A battery using the polyradical compound as an electrode active material has excellent high output characteristics as compared with a conventional lithium ion battery. This is because a large current can be discharged at a time because the substituent of the polyradical compound has a large electrode reaction rate. Moreover, since the polyradical compound has an ether structure in the main chain, it is a flexible polymer and has a high affinity with the electrolytic solution. Therefore, ion conductivity at the time of charging / discharging is high, and a large output can be produced. In addition, since high output characteristics can be maintained even when the ratio of the crosslinking agent is made higher than when a polyradical compound having another crosslinking structure is used, charging and discharging are performed when a polyradical having a high crosslinking agent ratio is used. Since the volume change at the time is small and peeling from the conductivity-imparting agent hardly occurs, the capacity drop is small even when repeated charge / discharge is performed.

  In the present invention, the polyradical compound may 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. 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 relates to an electrode active material having a repeating structural unit represented by the general formula (1) and containing a polyradical compound crosslinked by the structure represented by the general formula (2), and the electrode active material We have proposed a new battery using As a result, an electrode active material capable of extracting a large current, a battery capable of producing a large output and having little reduction in capacity even after repeated charge and discharge, and an electrode active material having the above-described characteristics The polyradical compound which can become can be provided.

  FIG. 1 shows the configuration of one embodiment of the battery of the present invention. The battery shown in FIG. 1 has a configuration in which a positive electrode 5 and a negative electrode 3 are stacked so as to face each other with a separator 4 containing an electrolyte, and a positive electrode current collector 6 is stacked on the positive electrode 5. ing. These are externally covered with a stainless steel exterior 1 on the negative electrode side and a stainless steel exterior 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 therebetween. . In addition, when using solid electrolyte and gel electrolyte as electrolyte, it can replace with the separator 4 and can also be made into the form which interposes these electrolytes between electrodes.

  In the present invention, in such a configuration, the electrode active material used for the negative electrode 3 or the positive electrode 5 or both electrodes has a repeating structural unit represented by the general formula (1) and is represented by the general formula (2). It is an electrode active material containing the polyradical compound bridge | crosslinked by the structure made.

  From the viewpoint of battery capacity, the battery of the present invention is preferably a lithium battery using the above electrode active material as a positive electrode active material, particularly a lithium secondary battery.

[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 contains a polyradical compound having a repeating unit structure represented by the general formula (1) as a repeating structural unit and crosslinked by the structure represented by the general formula (2). An electrode active material is used.

(In General formula (1), R < ¹ > -R < ³ > is respectively independently a hydrogen atom or a methyl group, R < ⁴ > -R < ⁵ > is respectively independently a hydrogen atom or a C1-C3 alkyl group, R < ⁶ > -R < ⁹ >. Each independently represents an alkyl group having 1 to 3 carbon atoms.)

(In the general formula (2), X represents a linear, branched, or cyclic alkylene group having 1 to 12 carbon atoms, or a linear, branched, or cyclic alkylenedioxy group, or phenylene group, or phenylene group having 1 to 12 carbon atoms. An oxy group or a divalent structure represented by the general formula (3) is shown. R ^{10 to} R ¹⁵ each independently represent a hydrogen atom or a methyl group.)

(In General Formula (3), Y represents a linear, branched, cyclic alkylene group, or phenylene group having 1 to 12 carbon atoms, or a divalent structure represented by General Formula (4) or General Formula (5). R ^{16 to} R ¹⁹ each independently represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.)

(In general formula (4), n represents an integer of 1 to 10.)

(In General Formula (5), Z represents a linear, branched, or cyclic alkylene group having 1 to 12 carbon atoms or an oxygen atom. M represents an integer of 1 to 10.)
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.

  A polyradical compound having only a repeating structural unit represented by the general formula (1) that is not crosslinked is known, but this structure has high solubility in an organic solvent and is difficult to fix to an electrode. In the present invention, it is possible to make the polyradical compound having the repeating structural unit represented by the general formula (1) difficult to dissolve in an organic solvent by crosslinking with the structure represented by the general formula (2), and the electrode It became possible to fix to.

  The molar ratio of the repeating structural unit represented by the general formula (1) and the structure represented by the general formula (2) is preferably 5: 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 (6) to (14).

  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 polymers that changes in the poly radical compound by such electrode reaction, the polyradical compound oxidizing the cation body and 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)
According to the synthesis scheme (15) shown below, a polyradical compound having a repeating unit structure represented by the above formula (6) was synthesized.

  Using tetrabutylammonium hydrogen sulfate as a phase transfer catalyst, epichlorohydrin and 4-hydroxy-TEMPO were stirred and reacted in a 50% by mass aqueous sodium hydroxide solution for 22.5 hours to obtain a TEMPO-substituted glycidyl ether. A THF solution (1 mol / L) of t-BuOK was added to a mixture of the obtained TEMPO-substituted glycidyl ether and 1,7-octadiene diepoxide and reacted at 65 ° C. for 6 hours to perform anion ring-opening polymerization, and acetonitrile. A crosslinked polyradical compound (6) insoluble in the above was obtained. In the crosslinked polyradical compound (6), the molar ratio of the TEMPO-substituted glycidyl ether unit to the crosslinked structure is 20: 1.

Example 1
200 mg of the crosslinked polyradical compound (6) obtained in Synthesis Example (1), 700 mg of graphite powder, and 100 mg of polytetrafluoroethylene resin 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 13.1 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 3: 7) 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) 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. Further, a lithium disk serving as a negative electrode was laminated, and a negative electrode side stainless steel exterior (manufactured by Kasuga) was superposed with an insulating packing disposed around the negative electrode. By applying pressure with a caulking machine, a closed coin-type battery using a crosslinked polyradical compound (6) as a positive electrode active material and metallic lithium as a negative electrode active material was obtained.

  The coin battery was charged with a constant current of 2 mA until the voltage reached 4.0 V, and then discharged to 3.0 V with a constant current of 2 mA. As a result, the voltage became almost constant for 1 hour and 3 minutes around 3.5 V, and then dropped rapidly. The discharge capacity per electrode active material was 90.6 mAh / g. Similarly, charging / discharging was repeated 100 times in the range of 4.0 to 3.0V. As a result, in all of the 100 charging / discharging operations, the voltage was constant at around 3.5 V during discharging, and (100th discharging capacity) / (1st discharging capacity) was 88% (see FIG. 2).

(Example 2)
A coin battery was produced in the same manner as in Example 1 except that a propylene carbonate solution containing 1.0 mol / L LiBETI (Li (C ₂ F ₅ SO ₂ ) ₂ N) electrolyte salt was used as the electrolytic solution.

  The coin battery was charged with a constant current of 2 mA until the voltage reached 4.0 V, and then discharged to 3.0 V with a constant current of 2 mA. As a result, the voltage became substantially constant for 1 hour at around 3.5 V, and then dropped rapidly. The discharge capacity per electrode active material was 89.4 mAh / g. Similarly, charging / discharging was repeated 100 times in the range of 4.0 to 3.0V. As a result, in all of the 100 charging / discharging operations, the voltage became constant at around 3.5 V during discharging, and (100th discharging capacity) / (1st discharging capacity) was 90%.

(Example 3)
In a small homogenizer container, 20 g of N-methyl-2-pyrrolidone was weighed, 400 mg of polyvinylidene fluoride was added, and stirred for 30 minutes to completely dissolve. Thereto, 1.0 g of the crosslinked polyradical compound (6) synthesized in Synthesis Example 1 was added and stirred for 5 minutes until the whole became a uniform orange color. Here, 600 mg of graphite powder was added, and further stirred for 15 minutes to obtain a slurry. The obtained slurry was applied on an aluminum foil and dried at 120 ° C. to produce a positive electrode. The thickness of the positive electrode layer was 130 μm. The produced electrode was not peeled off or cracked, and the surface was uniform. This was punched out into a circle with a diameter of 12 mm to mold a coin battery electrode. The mass of this electrode was 12.3 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 3: 7) containing 1.0 mol / L LiPF ₆ electrolyte salt was used. The electrode impregnated with the electrolytic solution was placed on the positive electrode side stainless steel exterior (manufactured by Kagatsu), and a polypropylene porous film separator impregnated with the electrolytic solution was laminated thereon. Furthermore, the copper foil which attached | coated the graphite layer used as a negative electrode on one side was laminated | stacked, and the negative electrode side stainless steel exterior (made by Kasuga) was piled up in the state which has arrange | positioned the insulating packing around. By applying pressure with a caulking machine, a closed coin-type battery using a crosslinked polyradical compound (6) as a positive electrode active material and graphite as a negative electrode active material was obtained.

  The coin battery was charged with a constant current of 2 mA until the voltage reached 4.0 V, and then discharged to 3.0 V with a constant current of 2 mA. As a result, the voltage became almost constant for 1 hour 30 minutes around 3.5 V, and then dropped rapidly. The discharge capacity per electrode active material was 90.3 mAh / g. Similarly, charging / discharging was repeated 100 times in the range of 4.0 to 3.0V. As a result, in all of the 100 charging / discharging operations, the voltage became constant at around 3.5 V during discharging, and ((100th discharge capacity) / (1st discharge capacity) was 89%.

Example 4
10 g of water was weighed into a container of a rotation and revolution type stirrer, 25 mg of carboxymethylcellulose was added, and the mixture was stirred for 30 minutes to be completely dissolved. Thereto, 100 mg of poly (tetrafluoroethylene) (PTFE) was added and further stirred, and 1.125 g of graphite powder was added and stirred again. Furthermore, 1.25 g of the crosslinked polyradical compound (6) synthesized in Synthesis Example 1 was added, and the mixture was further stirred for 15 minutes to obtain a slurry. The obtained slurry was applied on an aluminum foil and dried at 60 ° C. to produce a positive electrode. The thickness of the positive electrode was 100 μm. The produced electrode was not peeled off or cracked, and the surface was uniform. This was punched out into a circle with a diameter of 12 mm to mold a coin battery electrode. The mass of this electrode was 10.6 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 3: 7) containing 1.0 mol / L LiPF ₆ electrolyte salt was used. The electrode impregnated with the electrolytic solution was placed on the positive electrode side stainless steel exterior (manufactured by Kagatsu), and a polypropylene porous film separator impregnated with the electrolytic solution was laminated thereon. Further, a lithium disk serving as a negative electrode was laminated, and a negative electrode side stainless steel exterior (manufactured by Kasuga) was superposed with an insulating packing disposed around the negative electrode. By applying pressure with a caulking machine, a closed coin-type battery using a crosslinked polyradical compound (6) as a positive electrode active material and metallic lithium as a negative electrode active material was obtained.

  The coin battery was charged with a constant current of 2 mA until the voltage reached 4.0 V, and then discharged to 3.0 V with a constant current of 2 mA. As a result, a voltage flat portion was observed at around 3.5 V for 1 hour and 5 minutes. The discharge capacity per electrode active material was 88.5 mAh / g. As a result of repeating charge and discharge 100 times in the range of 4.0 to 3.0 V, (100th discharge capacity) / (first discharge capacity) was 91%.

(Example 5)
A crosslinked polyradical compound (11) synthesized by the same method as in Synthesis Example 1 was synthesized except that the compound of the following general formula (16) was used instead of 1,7-octadiene diepoxide. In the crosslinked polyradical compound (11), the molar ratio of the TEMPO-substituted glycidyl ether unit to the crosslinked structure is 10: 1.

  A coin battery was produced in the same manner as in Example 1 except that this crosslinked polyradical compound (11) was used. The positive electrode weight of this coin battery was 21.6 mg.

  The coin battery was charged with a constant current of 2 mA until the voltage reached 4.0 V, and then discharged to 3.0 V with a constant current of 2 mA. As a result, a flat voltage portion was observed at around 3.5 V for 1 hour and 40 minutes. The discharge capacity per electrode active material was 89.3 mAh / g. As a result of repeating charge and discharge 100 times in the range of 4.0 to 3.0 V, (100th discharge capacity) / (first discharge capacity) was 89%.

(Comparative Example 1)
A coin battery was produced in the same manner as in Example 1 except that a crosslinked polyradical compound represented by the following general formula (17) was used instead of the crosslinked polyradical compound (6). In the crosslinked polyradical compound represented by the general formula (17), the molar ratio between the TEMPO-substituted methacrylate unit and the crosslinked structure is 50: 1.

  As a result of charging and discharging the coin battery in the range of 3.0 to 4.0 V in the same manner as in Example 3, the voltage became almost constant for 1 hour and 17 minutes near 3.5 V, and then dropped rapidly. . The discharge capacity per electrode active material was 85.1 mAh / g. Similarly, as a result of repeating the charge / discharge cycle 100 times in the range of 3.0 to 4.0 V, (discharge capacity at the 100th cycle) / (discharge capacity at the first cycle) was 73% (see FIG. 2). ).

(Comparative Example 2)
A coin battery was produced in the same manner as in Example 3 except that the crosslinked polyradical compound (17) was used instead of the crosslinked polyradical compound (6).

  As a result of charging and discharging the coin battery in the range of 3.0 to 4.0 V in the same manner as in Example 3, the voltage became substantially constant for 1 hour and 8 minutes near 3.5 V, and then dropped rapidly. . The discharge capacity per electrode active material was 79.3 mAh / g. Similarly, as a result of repeating the charge / discharge cycle 100 times in the range of 3.0 to 4.0 V, (discharge capacity at the 100th cycle) / (discharge capacity at the first cycle) was 70%.

It is a conceptual diagram which shows the structure of one Embodiment of the structure of the battery of this invention. 6 is a graph of cycle test results of Example 1 and Comparative Example 1.

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 (5)

A polyradical compound having a repeating structural unit represented by the following general formula (1) and crosslinked by a structure represented by the following general formula (2).

(In General formula (1), R < ¹ > -R < ³ > is respectively independently a hydrogen atom or a methyl group, R < ⁴ > -R < ⁵ > is respectively independently a hydrogen atom or a C1-C3 alkyl group, R < ⁶ > -R < ⁹ >. Each independently represents an alkyl group having 1 to 3 carbon atoms.)

(In the general formula (2), X represents a linear, branched, or cyclic alkylene group having 1 to 12 carbon atoms, or a linear, branched, or cyclic alkylenedioxy group, or phenylene group, or phenylene group having 1 to 12 carbon atoms. An oxy group or a divalent structure represented by the general formula (3) is shown. R ^{10 to} R ¹⁵ each independently represent a hydrogen atom or a methyl group.)

(In General Formula (3), Y represents a linear, branched, cyclic alkylene group, or phenylene group having 1 to 12 carbon atoms, or a divalent structure represented by General Formula (4) or General Formula (5). R ^{16 to} R ¹⁹ each independently represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.)

(In general formula (4), n represents an integer of 1 to 10.)

(In General Formula (5), Z represents a linear, branched, or cyclic alkylene group having 1 to 12 carbon atoms or an oxygen atom. M represents an integer of 1 to 10.)   The polyradical compound according to claim 1, wherein the molar ratio of the repeating structural unit represented by the general formula (1) to the structure represented by the general formula (2) is 5: 1 to 1000: 1.   At least an electrode active material used for at least one of the positive electrode and the negative electrode of a battery having a positive electrode, a negative electrode, and an electrolyte as a constituent element contains the polyradical compound according to claim 1 or 2. Electrode active material.   A battery comprising at least a positive electrode, a negative electrode, and an electrolyte as constituents, wherein the electrode active material according to claim 3 is used for at least one of the positive electrode and the negative electrode.   The battery according to claim 4, wherein the electrode active material is used at least for a positive electrode.

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