JP5429596B2 - Secondary battery and manufacturing method thereof - Google Patents

Description

  The present invention relates to a secondary battery using a polymer radical material as an electrode active material for at least one of a positive electrode and a negative electrode, a method for producing the secondary battery, a method for charging and discharging the secondary battery, an electrode for a secondary battery, and The present invention relates to a method for manufacturing a secondary battery electrode.

  In recent years, portable electronic devices such as notebook computers and mobile phones have rapidly spread with the development of communication systems.

  While these portable electronic devices are highly functional, diversification of functions and shapes is also progressing.

  Therefore, various demands such as small size, light weight, high energy density, and high output density are increasing for the battery as the power source of these portable electronic devices.

  As a battery having a high energy density, a lithium ion battery has been widely used since the 1990s.

  This lithium ion battery uses a lithium-containing transition metal oxide such as lithium manganate or lithium cobaltate as an electrode active material and carbon as a negative electrode. Insertion / desorption of lithium ions into the electrode active material is possible. Charging / discharging is performed using a separation reaction.

  Lithium ion batteries have a large energy density and are excellent in cycle characteristics, and thus are used in various electronic devices such as mobile phones.

  On the other hand, the lithium ion battery has a drawback that it is difficult to obtain a large output and it takes a long time for charging.

  On the other hand, an electric double layer capacitor is known as an electricity storage device having a large output.

  Since the electric double layer capacitor can discharge a large current at once, a large output can be obtained.

  However, since the electric double layer capacitor has a very low energy density and is difficult to reduce in size, it is not suitable as a power source for many portable electronic devices.

  In order to obtain a lightweight electrode material, a battery using a sulfur compound or an organic compound as an electrode active material has been developed.

  For example, Patent Document 1 proposes a battery using an organic compound having a disulfide bond as a positive electrode (Patent Document 1).

  This battery utilizes an electrochemical redox reaction involving generation and dissociation of disulfide bonds as the 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, this battery has drawbacks that the capacity of the battery is likely to decrease with repeated charge / discharge cycles due to the low efficiency of recombining dissociated bonds and the diffusion of the electrode active material into the electrolyte.

  In addition, as a battery using an organic compound, a battery using a conductive polymer as an electrode active 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.

  Here, the dope reaction is a reaction in which a counter ion is doped into a charged radical generated by oxidation or reduction of a conductive polymer.

  For example, Patent Document 2 discloses a battery using a conductive polymer as a positive electrode or negative electrode material (Patent Document 2).

  This battery was composed only of elements having a small specific gravity such as carbon and nitrogen, and was expected as a high capacity battery.

  However, conductive polymers have the property that charged radicals generated by redox are delocalized over a wide range of π-electron conjugated systems and interact with each other, resulting in electrostatic repulsion and radical disappearance. .

  This limits the dope concentration, i.e. limits the capacity of the battery.

  For example, it has been reported that the doping rate of a battery using polyaniline as a positive electrode is 50% or less, and 7% in the case of polyacetylene.

  A battery using a conductive polymer as an electrode material has a certain effect in terms of weight reduction, but a battery having a large energy density has not been obtained.

  A non-aqueous electrolyte capacitor using a conductive polymer as an electrode material has also been proposed (Patent Document 3).

  This non-aqueous electrolyte capacitor can provide a large output and has a higher energy density than a conventional electric double layer capacitor.

  However, like the battery using a conductive polymer as an electrode active material, the generated dope concentration is limited and the energy density is small.

  On the other hand, Patent Document 4 discloses a secondary battery in which at least one active material of a positive electrode and a negative electrode contains a radical material. Patent Documents 5 and 6 disclose a nitroxyl polymer material in the positive electrode. Have been proposed (Patent Documents 4, 5, and 6).

  These power storage devices such as secondary batteries can charge and discharge with a large current because the electrode reaction of the electrode active material (radical compound) itself is fast, and therefore high output is obtained.

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

  However, in the secondary battery or power storage device using the radical compound proposed in Patent Documents 4 to 6, the radical compound constituting the positive electrode or the like is an aliphatic organic compound, and its own conductivity is extremely low.

  Therefore, in order to charge and discharge using a radical compound as an electrode active material, a conductive material (conducting agent) is added so that the electrical resistance of the electrode can be reduced and the radical compound and electrons can be efficiently transferred. There is a need.

  Carbon materials such as carbon fiber and carbon black have been used as the conductivity-imparting agent in that it has a relatively large surface area and is easily mixed with a polymer radical material.

  However, when these are used, there is a problem in that the proportion of radicals that cannot participate in charging / discharging is relatively large and the battery capacity becomes small.

  Furthermore, there is a problem that the battery capacity is extremely reduced because the voltage drop becomes large during discharging with a large current.

  In addition, an electrode using a polymer radical material is prepared by applying a slurry-like liquid in which a polymer radical material and a carbon material are dispersed or dissolved in an organic solvent on an aluminum foil and then evaporating the solvent. Yes.

  However, the radical material contracts when the solvent evaporates, and there is a problem that the obtained electrode shows large warpage, cracks, and peeling from the aluminum foil used as a current collector.

  In particular, this phenomenon becomes remarkable when the ratio of the radical material in the electrode is high, and it is difficult to produce an electrode containing 50% by weight or more of the radical material.

  The present invention has been made in view of the above reasons, and an object of the present invention is to provide a secondary battery in which the flatness of an electrode is higher than that of the prior art and has a higher capacity than the prior art.

  More specifically, the present invention provides a secondary battery using an electrode having high flatness without causing warpage, cracking, or peeling from an aluminum foil even when the ratio of the polymer radical material is 50% by weight or more of the total electrode material. That is.

  In order to achieve the above-described object, the present inventors have intensively studied. As a result, carbon fibers having an average fiber diameter of 0.01 to 0.5 μm and an average fiber length of 15 to 100 μm and having no branched structure are used as a conductivity-imparting agent. It has been found that the above-mentioned problems can be solved by using it.

  That is, by using this carbon fiber, even when the ratio of the polymer radical material is 50% by weight or more of the total electrode material, warpage, cracking, and peeling from the aluminum foil are not observed, and an electrode having high flatness can be obtained. I found out.

In order to achieve the above-mentioned object, the first invention has a positive electrode and a negative electrode, and a polymer radical material is used as an electrode active material for at least one of the positive electrode and the negative electrode. the average fiber diameter 0.01~0.5μm in said electrode having a radical material, a secondary battery, characterized by containing the carbon fibers having no branch structure having an average fiber length of 15 to 100 m.

In the second invention, the polymer radical material described in the first invention is mixed with a binder resin, a solvent, and the carbon fiber described in claim 1, and a shear rate of 3 × 10 ⁴ to 1 × 10 ⁵ (1 / s), and a process for producing an electrode using an electrode ink having a viscosity at 25 ° C. of 50 Pa · s or less.

  3rd invention is the charging / discharging method characterized by using the secondary battery as described in 1st invention.

A fourth invention is a two and comprising a polymer radical material, the average fiber diameter 0.01 to 0.5 [mu] m, and the carbon fiber having no branch structure having an average fiber length 15 to 100 m, the following It is an electrode for a battery.

According to a fifth aspect of the present invention, the polymer radical material according to the fourth aspect is mixed with a binder resin, a solvent, and the carbon fiber according to the twelfth aspect, and a shear rate of 3 × 10 ⁴ to 1 × 10 ⁵ (1 / s), and a method for producing an electrode for a secondary battery, comprising a step of producing an electrode using an electrode ink having a viscosity at 25 ° C. of 50 Pa · s or less.

A sixth invention is a polymer radical material as an electrode active material, a binder resin, a solvent and an average fiber diameter of 0.01 to 0.5 [mu] m, the carbon fiber having no branch structure having an average fiber length of 15~100μm It is the ink for secondary battery electrodes characterized by containing.

  According to the present invention, an electrode having higher flatness than the conventional one can be obtained.

  In addition, the ratio of radical sites that cannot participate in charge / discharge is reduced compared to the conventional case. As a result, a secondary battery having a higher capacity than before can be obtained.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail based on the drawings.

  First, with reference to FIG. 1 and FIG. 2, the structure of the battery 1 which concerns on the 1st Embodiment of this invention is demonstrated.

  Here, as the battery 1, a secondary battery having an electrode containing a polymer radical material and carbon fiber in at least one of a positive electrode and a negative electrode is illustrated.

  1 and 2 includes a positive electrode 11 formed on a positive electrode current collector 12 (aluminum foil or the like) having a positive electrode lead 13 and a negative electrode current collector 17 (metal foil or the like) having a negative electrode lead 15. ) And the negative electrode 16 disposed on the top of the negative electrode 16 so as to face each other with a separator 14 containing an electrolyte interposed therebetween.

  These are sealed with an exterior film 18 (such as an aluminum laminate exterior body).

  In addition, when using solid electrolyte and gel electrolyte as electrolyte, it can replace with the separator 14 and can also be made into the form which interposes these electrolytes between electrodes.

  In the present embodiment, in such a configuration, at least one of the positive electrode 11 and the negative electrode 16 is an electrode mainly composed of a polymer radical material and a carbon fiber described later.

  However, the battery 1 uses the above-mentioned polymer radical material and an electrode mainly composed of carbon fiber for the positive electrode 11 and a lithium intercalation compound such as lithium or carbon for the negative electrode 16 because a high voltage can be obtained. It is preferable to use it.

  The main component of the electrode mainly composed of the above-mentioned polymer radical material and carbon fiber can be combined with other electrode active materials and conductive agents. Further, a binder or a thickener can be added for the purpose of increasing the stability of the electrode or facilitating the production.

  Next, each component of the electrode mainly composed of the polymer radical material and carbon fiber will be described in more detail.

[Polymer radical material]
The polymer radical material in the present invention functions as an electrode active material in a secondary battery, and is a substance that directly contributes to electrode reactions such as charge reaction and discharge reaction.

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

  The nitroxyl radical material can be repeatedly charged and discharged by the reaction used in the following reaction formula (A).

  That is, a nitroxyl polymer compound having a radical partial structure represented by chemical formula (I) in the reduced state and a nitroxyl cation partial structure represented by chemical formula (II) in the oxidized state is obtained.

  The structure of the nitroxyl radical material changes from a nitroxyl radical structure to a nitroxyl cation structure during charging and from a nitroxyl cation structure to a nitroxyl radical structure during discharge.

  Note that Reaction Formula A represents the electrode reaction of the positive electrode, and the polymer radical material that accompanies such a reaction can function as a material for an electricity storage device that stores and releases electrons.

  The oxidation-reduction reaction shown in Reaction Formula A is a reaction mechanism that does not involve a change in the structure of the organic compound. Therefore, the reaction rate is high. It is possible to flow.

  In the present invention, the nitroxyl polymer compound includes a piperidinoxyl radical represented by the chemical formula (6), a pyrrolidinoxyl radical represented by the chemical formula (7), and a chemical formula (8) from the viewpoint of long-term stability. More preferred are those having a group selected from the group consisting of pyrrolinoxyl radicals represented by (2), and further 2,2,6,6-tetramethylpiperidinoxyl radicals represented by (9), chemical formula (10) And those having a 2,2,5,5-tetramethylpyrrolinoxyl radical represented by the formula (2) and a 2,2,5,5-tetramethylpyrrolinoxyl radical structure represented by the chemical formula (11) are more preferred.

(R _{1 to} R ₄ in the general formulas (6), (7), and (8) represent an alkyl group having 1 to 4 carbon atoms)

  Examples of the structure of the main chain polymer include polyalkylene polymers such as polyethylene, polypropylene, polybutene, polydecene, polydodecene, polyheptene, polyisobutene, and polyoctadecene; diene polymers such as polybutadiene, polychloroprene, polyisoprene, and polyisobutene; (Meth) acrylic acid; poly (meth) acrylonitrile; poly (meth) acrylamide polymers such as poly (meth) acrylamide, polymethyl (meth) acrylamide, polydimethyl (meth) acrylamide, polyisopropyl (meth) acrylamide; polymethyl (meta ) Polyalkyl (meth) acrylates such as acrylate, polyethyl (meth) acrylate, polybutyl (meth) acrylate; polyvinylidene fluoride, polytetraph Fluoropolymers such as oloethylene; polystyrene polymers such as polystyrene, polybromostyrene, polychlorostyrene, and polymethylstyrene; polyvinyl acetate, polyvinyl alcohol, polyvinyl chloride, polyvinyl methyl ether, polyvinyl carbazole, polyvinyl pyridine, polyvinyl pyrrolidone, etc. Vinyl polymers: Polyethylene oxide, polypropylene oxide, polybutene oxide, polyoxymethylene, polyacetaldehyde, polymethyl vinyl ether, polypropyl vinyl ether, polybutyl vinyl ether, polybenzyl vinyl ether, and other polyether polymers; polymethylene sulfide, polyethylene sulfide, polyethylene Disulfide, polypropylene sulfide, polypheny Polysulfide polymers such as polyethylene sulfide, polyethylene tetrafluoride, polyethylene trimethylene sulfide; polyesters such as polyethylene terephthalate, polyethylene adipate, polyethylene isophthalate, polyethylene naphthalate, polyethylene paraphenylene diacetate, polyethylene isopropylidene dibenzoate; Polyurethanes such as methylene ethylene urethane; polyketone polymers such as polyether ketone and polyallyl ether ketone; polyanhydride polymers such as polyoxyisophthaloyl; polyamines such as polyethylene amine, polyhexamethylene amine and polyethylene trimethylene amine Polymers; Polyamide polymers such as nylon (registered trademark), polyglycine, polyalanine; Polyimine polymers such as acetyliminoethylene and polybenzoyliminoethylene; Polyimide polymers such as polyesterimide, polyetherimide, polybenzimide, and polypyromimide; polyarylene, polyarylenealkylene, polyarylenealkenylene, polyphenol, phenol Resin, cellulose, polybenzimidazole, polybenzothiazole, polybenzoxazine, polybenzoxazole, olicarborane, polydibenzofuran, polyoxoisoindoline, polyfurantetracarboxylic acid diimide, polyoxadiazole, polyoxindole, polyphthalazine, Polyphthalide, Polycyanurate, Polyisocyanurate, Polypiperazine, Polypiperidine, Polypyrazinoquinoxane, Polypyrazole, Poly Polyaromatic polymers such as lipididazine, polypyridine, polypyrrole methymine, polyquinone, polypyrrolidine, polyquinoxaline, polytriazine, polytriazole; siloxane polymers such as polydisiloxane and polydimethylsiloxane; polysilane polymers; polysilazane polymers; Examples thereof include polyphosphazene polymers; polythiazyl polymers; conjugated polymers such as polyacetylene, polypyrrole, and polyaniline. In addition, (meth) acryl means methacryl or acrylic.

  Among these, it is preferable to have a polyalkylene polymer, poly (meth) acrylates, poly (meth) acrylamides, and polystyrene as a main chain structure in terms of excellent electrochemical resistance. The main chain is a carbon chain having the largest number of carbon atoms in the polymer compound.

  In the following, examples of units possessed by the nitroxyl polymer preferably used in the present invention include poly (4-methacryloyloxy-2,2,6,6-tetramethylpiperidine-1-oxyl) represented by the formula (12) , Poly (4-acryloyloxy-2,2,6,6-tetramethylpiperidine-1-oxyl) represented by the formula (13), poly (4-vinyloxy-2,2 represented by the formula (14) , 6,6-tetramethylpiperidine-1-oxyl).

  In addition, it is a preferable example that it is a copolymer and a crosslinked body which contain these as a component.

  Although the molecular weight of the nitroxyl polymer compound in the present invention is not particularly limited, it preferably has a molecular weight that makes it difficult to dissolve in the electrolyte when the electricity storage device is constructed, and this is the kind of the organic solvent in the electrolyte. It depends on the combination.

  In general, the weight average molecular weight is 1000 or more, preferably 10,000 or more, particularly 20000 or more, and 55,000 or less, preferably 500,000 or less.

  In addition, the polymer radical material may be cross-linked, and thereby the solubility in the electrolyte can be lowered, so that the durability against the electrolytic solution can be improved.

  Moreover, in the electrode active material of one electrode of the battery of the present invention, the polymer radical material used in the present invention can be used alone, but two or more kinds may be used in combination. Moreover, you may use in combination with another electrode active material.

  At this time, it is preferable that 10 to 90 mass% of the polymer radical material used in the present invention is contained in the electrode active material, and more preferably 20 to 80 mass%.

When the polymer radical material used in the present invention is used for a 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, as the metal oxide, for example, lithium manganate such as LiMnO ₂ , Li _x Mn ₂ O ₄ (0 <x <2) or lithium manganate having a spinel structure, MnO ₂ , LiCoO ₂ , LiNiO ₂ , Alternatively, Li _y V ₂ O ₅ (0 <y <2), olivine-based material LiFePO ₄ , a material obtained by substituting a part of Mn in the spinel structure with another transition metal, LiNi _0.5 Mn _1.5 O ₄ , LiCr _0.5 Mn _1.5 O ₄ , LiCo _0.5 Mn _1.5 O ₄ , LiCoMnO ₄ , LiNi _0.5 Mn _0.5 O ₂ , LiNi _0.33 Mn _0,33 Co _0.33 O ₂ , _{LiNi 0.8 Co 0.2 O 2, LiN} 0.5 Mn 1.5-z Ti z O 4 (0 <z <1.5), and the like. Examples of the disulfide compound include dithioglycol, 2,5-dimercapto-1,3,4-thiadiazole, S-triazine-2,4,6-trithiol and the like.

  Examples of other stable radical compounds include 2,2, -diphenylpicryl-1-hydrazyl, galvinoxyl, 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 polymer radical material used in the present invention is used for the negative electrode, other electrode active materials are not particularly limited, but graphite, amorphous carbon, lithium alloy, conductive polymer, and the like can be used. Moreover, you may use another stable radical compound.

  These shapes are not particularly limited. For example, metallic lithium is not limited to a thin film shape, and may be a bulk shape, a powdered shape, a fiber shape, a flake shape, or the like. Among these, it is preferable to combine with metallic lithium or graphite.

  These other electrode active materials can be used alone or in combination of two or more.

  The battery of the present invention uses the polymer radical material used in the present invention as an electrode active material in one electrode reaction of the positive electrode or the negative electrode, or both electrode reactions, but when used as an electrode active material in one electrode reaction, A conventionally known electrode active material as exemplified above can be used as the electrode active material in the other electrode.

  In addition, these electrode active materials can also be used individually or in combination of 2 or more types. Furthermore, at least one of these electrode active materials may be used in combination with the polymer radical material used in the present invention. Moreover, the polymeric radical material used by this invention can also be used independently.

In the present invention, it is sufficient that the polymer radical material used in 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. Absent. However, from the viewpoint of energy density, it is particularly preferable to use this polymer radical material as the positive electrode active material. At this time, it is preferable to use this polymer radical material alone as the positive electrode active material. However, it can also be used in combination with another positive electrode active material, and as the other positive electrode active material 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.

[Carbon fiber]
The carbon fiber used in the present invention is used for the purpose of reducing the impedance of the electrode and improving the energy density and output characteristics.

  The average fiber diameter of the carbon fibers used in the present invention is preferably 0.01 to 0.5 μm. When the average fiber diameter is larger than 0.5 μm, the effect of lowering the impedance is remarkably reduced, which is not preferable. On the other hand, if it is smaller than 0.01 μm, the handleability deteriorates, which is not preferable. A more preferable average fiber diameter is 0.05 to 0.4 μm.

  The average fiber length of the carbon fibers used in the present invention is preferably 15 to 100 μm. If the average fiber diameter is smaller than 15 μm, the electrode may be warped or cracked, which is not preferable. Moreover, when larger than 100 micrometers, the surface smoothness of an electrode may worsen and it is unpreferable. A more preferable average fiber length is 20 to 100 μm.

  The carbon fiber used in the present invention preferably has substantially no branched structure. Here, substantially having no branched structure is a mode in which a plurality of ultrafine carbon fibers extend, and does not have a granular portion that bonds the carbon fibers to each other, that is, a superfine carbon fiber mainly composed of carbon fibers. In other words, it means that branch-like ultrafine fibers are not formed, but does not exclude fibers having a branched structure within a range in which the target performance of the present invention is maintained.

  If it has a branched structure, the electrode may be warped, cracked, and peeled off from the aluminum foil, which is not preferable.

  The carbon fiber used in the present invention has a lattice spacing (d002) measured and evaluated by X-ray diffraction method in the range of 0.336 nm to 0.338 nm, and the crystallite size (Lc002) in the range of 50 nm to 150 nm. Preferably there is. When the lattice spacing is larger than 0.338 or when the crystallite size is smaller than 50 nm, the effect of lowering the impedance is reduced, which is not preferable.

  The carbon fiber used in the present invention preferably has a volume resistivity (ER) measured using a 4-probe type electrode unit in the range of 0.008 Ω · cm to 0.015 Ω · cm. When the volume resistivity is larger than 0.015 Ω · cm, the effect of lowering the impedance is reduced, which is not preferable.

  Carbon fiber can be used alone, but can also be used by mixing with other conductivity-imparting agents.

  Other conductive agents include carbonaceous fine particles such as graphite, carbon black, and acetylene black; carbon fibers such as vapor grown carbon fiber (VGCF) and carbon nanotube; and conductive properties such as polyaniline, polypyrrole, polythiophene, polyacetylene, and polyacene. Examples include polymers.

  As for the ratio of the electrical conductivity imparting agent in an electrode, 5-80 mass% of the whole is preferable.

[Binder]
In order to strengthen the connection between the constituent materials of the electrode, a binder can also be used. 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 (binder resins) 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.

[Thickener]
In order to make it easy to produce an electrode slurry described later, a thickener can also be used. Such thickeners include carboxymethyl cellulose, polyethylene oxide, polypropylene oxide, hydroxyethyl cellulose, hydroxypropyl cellulose, carboxymethyl hydroxyethyl cellulose, polyvinyl alcohol, polyacrylamide, hydroxyethyl polyacrylate, ammonium polyacrylate, polyacrylic acid Examples include soda.

  These thickeners can be used alone or in admixture of two or more. As a ratio of the thickener in an electrode, 0.1-10 mass% is preferable.

[catalyst]
In order to perform the electrode reaction more smoothly, a catalyst that assists the oxidation-reduction reaction can also 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.

  Next, materials other than the electrodes in the battery 1 will be described.

[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, and the like can be used. In view of potential stability, the positive electrode current collector is particularly preferably an aluminum foil, and the negative electrode current collector is preferably a copper foil. The current collector may have a catalytic effect, or the electrode active material and the current collector may be chemically bonded.

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

[Electrolytes]
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. . 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.

  Next, an electrode manufacturing method, a battery shape, and a battery manufacturing method will be described.

[Electrode manufacturing method]
The method for producing the electrode is not particularly limited, and a method appropriately selected according to the material can be used. However, as the most general production method, the above-described carbon fiber and binder are used for the polymer radical material. A method of obtaining an electrode by mixing an agent and a solvent and further stirring to form a slurry-like uniform dispersion, applying this to an electrode current collector, and volatilizing the solvent at room temperature or at room temperature.

  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-methylpyrrolidinone; aromatics such as benzene, toluene and xylene. Aliphatic hydrocarbon solvents such as hexane and heptane; halogenated hydrocarbon solvents such as chloroform, dichloromethane, dichloroethane, trichloroethane, and carbon tetrachloride; alkyl ketone solvents such as acetone and methyl ethyl ketone; methanol, Examples include alcohol solvents such as ethanol and isopropyl alcohol; dimethyl sulfoxide, water and the like.

As conditions for preparing the dispersion, it is preferable that the shear rate during stirring is 3 × 10 ⁴ to 1 × 10 ⁵ (1 / s) and the viscosity at 25 ° C. is 50 Pa · s or less. Is preferably dispersed in the range of 5 × 10 ⁴ to 8 × 10 ⁴ (1 / s), and the viscosity at 25 ° C. is preferably in the range of 1 Pa · s to 50 Pa · s. The shear rate is calculated as S / d from the gap (d) between the inner wall of the outer part of the dispersion stirrer and the outer wall of the rotating body and the peripheral speed (S) of the rotating body. The measurement of the viscosity is preferably 50 Pa · s or less in the range of the angular velocity of the cone plate from 1 to 1000 (rad / s) using a cone plate viscometer (manufactured by Harke).

  If the shear rate is lower than 3 × 10 (1 / s), the above-described carbon fibers are not easily dispersed, and a uniform dispersion cannot be obtained, and the dispersion is caused by an excessive shear rate and an excessive viscosity. If this is done, the carbon fiber itself described above is cut and the original function of the carbon fiber cannot be maintained.

  A method used for applying the dispersion to the electrode current collector to produce a positive electrode or a negative electrode is not particularly limited, and a printing method or a coating method can be used.

  For example, screen printing method, rotary screen printing method, gravure printing method, gravure offset printing method, flexographic printing method, die coating method, cap coating method, roll coating method, etc. can be used, among which screen printing method, rotary screen printing The method is more preferable.

  In addition, when manufacturing an electrode, it is prepared using a polymer radical material itself used in the present invention as an electrode active material, or a polymer that changes to a polymer radical material used in the present invention by an electrode reaction. There are cases.

Examples of the polymer that changes to the polymer radical material by such an electrode reaction include a lithium salt or sodium salt comprising an anion obtained by reducing the polymer radical material and an electrolyte cation such as lithium ion or sodium ion, or the cationic material a polymeric radical material was oxidized and PF ₆ ^- or BF ₄ ^-, etc. salt comprising the electrolyte anions such like.

  Next, a battery shape and a manufacturing method will be described.

[Battery shape]
In the present embodiment, a square shape as shown in FIG. 1 is exemplified as the shape of the battery, but in the present invention, the shape of the battery is not particularly limited, and a conventionally known shape can be adopted.

  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.

  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-methylpyrrolidinone; aromatics such as benzene, toluene and xylene. Aliphatic hydrocarbon solvents such as hexane and heptane; halogenated hydrocarbon solvents such as chloroform, dichloromethane, dichloroethane, trichloroethane, and carbon tetrachloride; alkyl ketone solvents such as acetone and methyl ethyl ketone; methanol, Examples include alcohol solvents such as ethanol and isopropyl alcohol; dimethyl sulfoxide, water and the like.

[Battery manufacturing method]
As a method for producing a battery, there may be mentioned a method in which an electrode is stacked or wound with a counter electrode and a separator interposed therebetween, wrapped in an outer package, and injected with an electrolytic solution and sealed.

  When manufacturing a battery, the polymer radical material used in the present invention itself is used as an electrode active material, and a polymer that changes to the polymer radical material used in the present invention by an electrode reaction is used. Sometimes a battery is manufactured.

Examples of the polymer that changes to the polymer radical material by such an electrode reaction include a lithium salt or sodium salt comprising an anion obtained by reducing the polymer radical material and an electrolyte cation such as lithium ion or sodium ion, or the cationic material a polymeric radical material was oxidized 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 demonstrated more concretely using an Example, this invention is not limited to these Examples.

Example 1
A thin organic radical battery (secondary battery) was prepared and charged / discharged using an electrode containing a radical compound (polymer radical material) represented by the following formula (15) and carbon fiber (CNF) used in the present invention.

(1) Preparation of carbon fiber (CNF) First, the carbon fiber used by this invention was created and compared with the commercially available carbon fiber.

  Specifically, first, 90 parts by mass of high-density polyethylene (HI-ZEX (registered trademark) 5000SR, manufactured by Prime Polymer Co., Ltd.) and 10 parts by mass of synthetic mesophase pitch AR / MPH (manufactured by Mitsubishi Gas Chemical Co., Inc.) are arranged in the same direction. A resin composition was prepared by melt-kneading with a biaxial extruder (TEM-26SS manufactured by Toshiba Machine Co., Ltd., barrel temperature 310 ° C., under nitrogen stream).

  Next, the resin composition was spun from a spinneret at 390 ° C. with a cylinder-type single-hole spinning machine to prepare a precursor molded body (a sea-island type composite fiber containing a carbon fiber precursor as an island component). At this time, it adjusted so that the fiber diameter of a precursor molded object might be set to 190 micrometers. Next, the precursor molded body was heated to 215 ° C. at a temperature rising rate of 1 ° C./min with a hot air dryer and held at 215 ° C. for 3 hours to obtain a stabilized precursor molded body.

  Next, the stabilized precursor molded body is heated to 500 ° C. at a rate of temperature increase of 5 ° C./min in a nitrogen gas atmosphere, and held at 500 ° C. for 1 hour, thereby removing fibrous carbon from which high-density polyethylene has been removed. A precursor was formed. The fibrous carbon precursor was heated from room temperature to 1000 ° C. at a heating rate of 5 ° C./min in a nitrogen atmosphere and held at 1000 ° C. for 30 minutes to obtain carbonized fibers.

  The carbonized fiber was heated to 3000 ° C. at a rate of temperature increase of 10 ° C./min in an argon gas atmosphere and held at 3000 ° C. for 30 minutes to obtain graphitized carbon fiber.

  An electron micrograph of the obtained carbon fiber is shown in FIG. As shown in FIG. 6, the obtained carbon fiber was found not to have a branched structure.

  Moreover, the average fiber diameter of the obtained carbon fiber was 280 nm, and the average fiber length was 33 μm. From the result of measurement by X-ray diffraction method, the lattice spacing (d002) is 0.3373 nm, which is considerably lower than 0.3386 nm of the commercially available product VGCF (registered trademark, carbon nanofiber using a vapor phase method, manufactured by Showa Denko KK). . Further, the crystallite size (Lc002) is 60 nm, which is considerably larger than 30 nm of the commercial product VGCF, which is extremely high crystallinity. The volume resistivity measured using a four-probe type electrode unit exhibiting conductivity characteristics was 0.010 Ω · cm, which was lower than 0.016 Ω · cm of the commercial product VGCF, and showed high conductivity.

(2) Production of Battery A positive electrode having a polymer radical material introduction rate (the ratio of polymer radical material in all electrode materials, the same applies hereinafter) using the above-described carbon fiber (CNF) was produced at 60%.

  90 parts of solvent N-methyl-2-pyrrolidinone (NMP) is added to 10 parts of binder resin polyvinylidene fluoride PVDF (Kureha KF # 1300), and PVDF is completely dissolved in advance using a dispersion stirrer to prepare a PVDF solution did.

  2.9 g of polyradical compound (polymer radical material) PTMA having a crosslinked structure and 4.8 g of PVDF solution were added to 30.9 g of NMP, and stirred using a dispersion stirrer until uniform to obtain a polyradical compound dispersion.

  Then, CNF1.4g was added to the obtained polyradical compound dispersion, and it stirred until it became uniform with the high shear type | mold dispersion stirrer, and obtained the ink for electrodes.

The shear rate at this time was about 7 × 10 ⁴ (1 / s). Further, the viscosity of the obtained electrode ink was about 20 Pa · s at 25 ° C.

  The obtained ink for electrodes was applied onto an aluminum current collector by stencil printing with a metal mask (stencil) (screen printer LS-150, manufactured by Neurong Seimitsu Kogyo), dried in a vacuum oven, pressed, and then subjected to film A positive electrode having a thickness of 65 μm and a width and width of 25 × 16 mm was obtained.

  The obtained positive electrode was not warped, cracked, or peeled off from the aluminum current collector. A photograph of this electrode is shown in FIG.

  An aluminum lead having a length of 65 mm and a width of 0.4 mm was welded to the aluminum foil surface of the positive electrode.

  Further, a lithium-laminated copper foil (lithium thickness 30 μm) was punched into a 25 × 16 mm rectangle like the positive electrode to form a metal lithium negative electrode, and a nickel lead 65 mm long and 0.4 mm wide was welded to the copper foil surface.

  A positive electrode, a porous polypropylene separator (30 × 20 mm rectangle), and a negative electrode were stacked in this order to face the radical positive electrode layer and the metal lithium negative electrode to form a power storage unit. Two sheets of aluminum laminate film (length 58 mm × width 52 mm × thickness 0.12 mm) that can be heat-sealed were heat-sealed to form a bag-like case, and a power storage unit was placed.

To this was added 0.12 cc of an electrolytic solution [ethylene carbonate / diethyl carbonate mixed solution containing 1.0 mol / L LiPF ₆ electrolyte salt (mixing volume ratio 3: 7)] in an aluminum laminate case. The number of moles of LiPF ₆ electrolyte salt in the added electrolyte is about 2.87 times the number of moles of radicals.

At this time, the ends of the electrodes with aluminum and nickel leads were taken out of 2.7 cm, and one side of the unlaminated aluminum laminate case was heat-sealed at a low pressure of 1.6 mmHg (2.1 × 10 ² Pa). As a result, the electrode and the electrolyte were completely sealed in the aluminum laminate case.

  A thin organic radical battery (length 58 mm × width 52 mm × thickness 0.3 mm) was produced by the above steps. The battery was charged at 0.112 mA and then discharged at various current levels. When discharged at 0.112 mA, discharging was performed at an average voltage of 3.619 V for 8 hours and 59 minutes, and the discharge capacity was 1.0 mAh. The discharge capacity density per active material is 99 mAh / g, and 90% of radicals are involved in charge / discharge.

(Comparative Example 1)
A battery using an electrode with a polymer radical material introduction rate of 30% using a commercially available VGCF was prepared and charged and discharged.

90 parts of solvent NMP was added to 10 parts of binder resin PVDF (Kureha KF # 1300), and PVDF was completely dissolved in advance using a dispersion stirrer to prepare a PVDF solution. Polyradical compound PTMA 1.4 g having a crosslinked structure and 4.8 g PVDF solution were added to 30.9 g of NMP, and the mixture was stirred using a dispersion stirrer until uniform to obtain a polyradical compound dispersion. Thereafter, 2.9 g of VGCF was added to the obtained polyradical compound dispersion and stirred with a dispersion stirrer until uniform to obtain an electrode ink. The obtained ink for electrodes was applied onto an aluminum current collector by stencil printing with a metal mask (stencil) (screen printer LS-150, manufactured by Neurong Seimitsu Kogyo), dried in a vacuum oven, pressed, and then subjected to film A positive electrode having a thickness of 35 μm and a width and width of 25 × 16 mm was obtained. An aluminum lead having a length of 65 mm and a width of 0.4 mm was welded to the aluminum foil surface of the positive electrode. Further, a lithium-laminated copper foil (lithium thickness 30 μm) was punched into a 25 × 16 mm rectangle like the positive electrode to form a metal lithium negative electrode, and a nickel lead 65 mm long and 0.4 mm wide was welded to the copper foil surface. A positive electrode, a porous polypropylene separator (30 × 20 mm rectangle), and a negative electrode were stacked in this order to face the radical positive electrode layer and the metal lithium negative electrode to form a power storage unit. Two sheets of aluminum laminate film (length 58 mm × width 52 mm × thickness 0.12 mm) that can be heat-sealed were heat-sealed to form a bag-like case, and a power storage unit was placed. To this, 0.09 cc of an electrolytic solution [ethylene carbonate / diethyl carbonate mixed solution containing 1.0 mol / L LiPF ₆ electrolyte salt (mixing volume ratio 3: 7)] was added. The number of moles of LiPF ₆ electrolyte salt in the added electrolyte is about 8.80 times the number of moles of radicals.

At this time, the ends of the aluminum and nickel leaded electrodes were taken out of 2.7 cm, and one side of the unlaminated aluminum laminate case was heat-sealed at a low pressure of 1.6 mmHg (2.1 × 10 ² Pa). As a result, the electrode and the electrolyte were completely sealed in the aluminum laminate case. A thin organic radical battery (length 58 mm × width 52 mm × thickness 0.3 mm) was produced as described above. The battery was charged at 0.027 mA and then discharged at a constant current of 0.027 mA. As a result, discharge was performed for 8 hours 48 minutes at an average voltage of 3.620 V, and the discharge capacity was 0.241 mAh. The discharge capacity density per active material was 82 mAh / g. Since the discharge capacity density when all radicals are involved in charge / discharge is 108 mAh / g, 76% of radicals are involved in charge / discharge.

  Next, the discharge capacity in Example 1 and Comparative Example 1 was compared with the obtained capacity.

  FIG. 3 is a graph showing the relationship between the discharge capacity (horizontal axis) and the obtained capacity (vertical axis) in Example 1 and Comparative Example 1.

  In the graph of FIG. 3, the symbols indicated by squares are plots of data of Example 1, and the symbols indicated by triangles are plots of data of Comparative Example 1.

  Compared with the battery produced in Comparative Example 1 (battery using an electrode having a radical introduction rate of 30% using VGCF), the battery of Example 1 has a capacity of four times or more, and a larger current. Discharge was possible.

(Comparative Example 2)
Next, as another comparative example, a positive electrode having a polymer radical material introduction rate of 60% using a commercially available VGCF was manufactured.

  90 parts of solvent NMP was added to 10 parts of binder resin PVDF (Kureha KF # 1300), and PVDF was completely dissolved in advance using a dispersion stirrer to prepare a PVDF solution.

  A polyradical compound dispersion was obtained by adding 2.9 g of a polyradical compound PTMA having a crosslinked structure and 4.8 g of a PVDF solution to 30.9 g of NMP, and stirring until uniform using a dispersion stirrer.

  Then, VGCF1.4g was added to the obtained polyradical compound dispersion, and it stirred until it became uniform with the dispersion stirrer, and ink for electrodes was obtained. The obtained electrode ink was applied onto an aluminum current collector by stencil printing using a metal mask (stencil) (screen printer LS-150, manufactured by Neurong Seimitsu Kogyo) and dried in a vacuum oven.

  The obtained positive electrode was warped, cracked, and peeled off from the aluminum current collector. A photograph of this electrode is shown in FIG.

  As described above, when an electrode using a polymer radical material as an electrode active material is prepared from a slurry using an organic solvent, a carbon fiber having a branched structure, an average fiber diameter of 0.15 μm, and an average fiber length of 10 μm is used. When the ratio of the polymer radical material in the electrode was about 30%, electrode warpage, cracking, and peeling from the aluminum current collector were not observed, and it was possible to produce the electrode (Comparative Example 1).

  However, when the ratio of the polymer radical material in the electrode was high, electrode warpage, cracking, and peeling from the aluminum current collector were observed (Comparative Example 2).

  On the other hand, by using carbon fibers having an average fiber diameter of 0.28 μm and an average fiber length of 33 μm and not having a branched structure, even when the ratio of the polymer radical material in the electrode is high, electrode warpage, cracking, aluminum current collection No peeling from the body was observed (Example 1).

  Comparing the capacity of the prepared electrodes, the capacity of the electrode using carbon fibers having no branch structure, an average fiber diameter of 0.28 μm, and an average fiber length of 33 μm, has a branch structure, an average fiber diameter of 0.15 μm, and an average When the carbon fiber having a fiber length of 10 μm was used, the capacity of the electrode was about 3 times.

  In the embodiments and examples described above, the case where the electrode including the radical compound and the carbon fiber used in the present invention is used as the radical positive electrode layer has been described. However, the present invention is not limited to this, Applicable to all electrodes containing compounds.

2 is a perspective view showing a battery 2. FIG. FIG. 2 is an exploded view of FIG. 1. It is a graph which shows the relationship between the discharge capacity (horizontal axis) of the battery produced in Example 1 and the battery produced in Example 2, and the obtained capacity (vertical axis). 2 is a photograph of an electrode manufactured in Example 1. 4 is a photograph of an electrode manufactured in Comparative Example 2. 2 is an electron micrograph of the carbon fiber obtained in Example 1. FIG.

Explanation of symbols

11 ......... Positive electrode 12 ......... Positive electrode current collector 13 ......... Positive electrode lead 14 ......... Separator 15 ......... Negative electrode lead 16 ......... Negative electrode 17 ......... Negative electrode current collector 18 ......... Exterior film

Claims (22)

A positive electrode;
A negative electrode,
Have
A polymer radical material is used as an electrode active material for at least one of the positive electrode and the negative electrode,
Secondary battery, wherein the average fiber diameter in said electrode having a polymer radical material 0.01 to 0.5 [mu] m, is included carbon fiber having no branch structure having an average fiber length of 15 to 100 m.   The carbon fiber has a lattice spacing (d002) measured by an X-ray diffraction method in a range of 0.336 nm to 0.338 nm and a crystallite size (Lc002) in a range of 50 nm to 150 nm. The secondary battery as described.   The carbon fiber is a carbon fiber having a volume resistivity (ER) measured in a range of 0.008 Ω · cm to 0.015 Ω · cm using a four-probe electrode unit. The secondary battery in any one of. The secondary battery according to any one of claims 1 to 3, wherein the polymer radical material is a nitroxyl polymer compound having a nitroxyl radical structure of the following general formula (1) in a repeating unit.
5. The nitroxyl polymer compound according to claim 4, which takes a nitroxyl radical partial structure represented by the following chemical formula (I) in a reduced state and a nitroxyl cation partial structure represented by the following chemical formula (II) in an oxidized state. Secondary battery.
6. The compound according to claim 4, wherein the nitroxyl polymer compound is a compound having at least one structure selected from nitroxyl radical structures represented by general formulas (3) to (5) in the side chain. A secondary battery according to any one of the above.
(R _{1 to} R ₄ in the general formulas (3), (4), and (5) represent an alkyl group having 1 to 4 carbon atoms.)   The nitroxyl polymer compound is poly (4-methacryloyloxy-2,2,6,6-tetramethylpiperidine-1-oxyl), poly (4-acryloyloxy-2,2,6,6-tetramethylpiperidine- The secondary battery according to any one of claims 4 to 6, wherein the secondary battery is a 1-oxyl) or a copolymer containing these as components.   The nitroxyl polymer compound is poly (4-vinyloxy-2,2,6,6-tetramethylpiperidine-1-oxyl) or a copolymer containing these as components. The secondary battery according to any one of claims 4 to 6.   The secondary battery according to claim 4, wherein the nitroxyl polymer compound has a crosslinked structure. The polymer radical material according to claim 1 is mixed with a binder resin, a solvent and the carbon fiber according to claim 1 and dispersed in a shear rate range of 3 × 10 ⁴ to 1 × 10 ⁵ (1 / s). And the manufacturing method of a secondary battery characterized by having the process of manufacturing an electrode using the ink for electrodes which made the viscosity in 25 degreeC 50 Pa.s or less.   A charge / discharge method using the secondary battery according to claim 1. A polymer radical material;
Carbon fibers without an average fiber diameter of 0.01 to 0.5 [mu] m, a branch structure having an average fiber length of 15 to 100 m,
An electrode for a secondary battery, comprising:   The carbon fiber has a lattice spacing (d002) measured by an X-ray diffraction method in a range of 0.336 nm to 0.338 nm and a crystallite size (Lc002) in a range of 50 nm to 150 nm. The electrode for secondary batteries as described.   The carbon fiber is a carbon fiber having a volume resistivity (ER) measured using a 4-probe type electrode unit in a range of 0.008 Ω · cm to 0.015 Ω · cm. The electrode for secondary batteries in any one of. The electrode for a secondary battery according to any one of claims 12 to 14, wherein the polymer radical material is a nitroxyl polymer compound having a nitroxyl radical structure represented by the following general formula (1) in a repeating unit.
The nitroxyl polymer compound takes a nitroxyl radical partial structure represented by the following chemical formula (I) in a reduced state and a nitroxyl cation partial structure represented by the following chemical formula (II) in an oxidized state. Secondary battery electrode.
The nitroxyl polymer compound is a compound having at least one structure selected from nitroxyl radical structures represented by general formulas (3) to (5) in the side chain. An electrode for a secondary battery according to claim 1.
(R _{1 to} R ₄ in the general formulas (3), (4), and (5) represent an alkyl group having 1 to 4 carbon atoms.)   The nitroxyl polymer compound is poly (4-methacryloyloxy-2,2,6,6-tetramethylpiperidine-1-oxyl), poly (4-acryloyloxy-2,2,6,6-tetramethylpiperidine- The secondary battery electrode according to any one of claims 15 to 17, wherein the electrode is a 1-oxyl) or a copolymer containing these as components.   The nitroxyl polymer compound is poly (4-vinyloxy-2,2,6,6-tetramethylpiperidine-1-oxyl) or a copolymer containing these as components. Item 18. The secondary battery electrode according to any one of Items 15 to 17.   The secondary battery electrode according to any one of claims 15 to 19, wherein the nitroxyl polymer compound has a crosslinked structure. The polymer radical material according to claim 12 is mixed with a binder resin, a solvent, and the carbon fiber according to claim 12, and dispersed in a shear rate range of 3 × 10 ⁴ to 1 × 10 ⁵ (1 / s). And the manufacturing method of the electrode for secondary batteries characterized by having the process of manufacturing an electrode using the ink for electrodes which made the viscosity in 25 degreeC 50 Pa * s or less. And wherein the polymer radical material as an electrode active material, a binder resin, a solvent and an average fiber diameter of 0.01 to 0.5 [mu] m, in that it contains carbon fibers having no branch structure having an average fiber length of 15~100μm Secondary battery electrode ink.