JP2002170568A - Battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new battery of high energy density and large capacity while being stable. SOLUTION: The battery is provided wherein, comprising at least a positive pole, a negative pole, and an electrolyte as components, the radical reaction occurs at least one of a charge process and a discharge process. Here, the radical compound generated through the radical reaction is stabilized so that charging/discharging is performed at high energy density, resulting in a battery of large capacity, high stability, and safety.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to at least a positive electrode,
The present invention relates to a battery having a negative electrode and an electrolyte as constituents and involving a radical reaction in at least one of charging and discharging. More specifically, a radical compound generated by a radical reaction in at least one of charge and discharge processes is stabilized, has a large energy density,
And a battery having excellent stability and safety.

[0002]

2. Description of the Related Art A battery is a device that converts chemical energy into electric energy by using an oxidation-reduction reaction that occurs at a positive electrode and a negative electrode and takes out the same, or converts electric energy into chemical energy and stores it. It is used as a power source in various devices. 2. Description of the Related Art In recent years, with the rapid market expansion of notebook personal computers, mobile phones, and the like, there has been an increasing demand for small and large-capacity batteries with a large energy density used for these. In order to meet this demand, a battery has been developed using an alkali metal ion such as lithium ion as a charge carrier and utilizing an electrochemical reaction accompanying the charge transfer. Among them, lithium-ion batteries are used in various electronic devices as large-capacity batteries with excellent stability and high energy density.

In such a lithium-ion battery, for example, a lithium-containing transition metal oxide is used as a positive electrode as an active material.
Carbon is used for the negative electrode, and charging / discharging is performed using a lithium ion insertion reaction and a desorption reaction with these active materials.

However, this lithium ion battery has a problem that the battery capacity per unit mass is not sufficient because a metal oxide having a large specific gravity is used as the active material of the positive electrode.

[0005] Attempts have been made to develop a large capacity battery using a lighter electrode material. For example, U.S. Pat.No. 4,833,048 and U.S. Pat.
Japanese Patent Application Laid-Open Publication No. H11-139,086 discloses a battery using an organic compound having a disulfide bond as an active material of a positive electrode. This utilizes the electrochemical redox reaction of an organic compound based on the formation and dissociation of disulfide bonds as the principle of a battery.

However, since this battery uses an organic compound mainly composed of an element having a low specific gravity, such as sulfur or carbon, as an electrode material, it has a certain effect in forming a high-capacity battery with a high energy density. However, there is a problem that the recombination efficiency of the dissociated disulfide bond is small, and the stability in the charged state or the discharged state is insufficient.

[0007] Also, as a battery using an organic compound as an active material, a battery using a conductive polymer as an electrode material has been proposed. This battery utilizes the principle of doping and undoping of electrolyte ions with respect to a conductive polymer. The doping reaction described here refers to excitons such as charged solitons and polarons generated by an electrochemical oxidation or reduction reaction of a conductive polymer.
It is defined as a reaction that is stabilized by a counter ion. On the other hand, the undoping reaction is defined as the reverse reaction of the doping reaction, that is, the reaction of electrochemically oxidizing or reducing excitons stabilized by counter ions.

US Pat. No. 4,442,187 discloses a battery using such a conductive polymer as an active material for a positive electrode or a negative electrode. Since this battery uses, as an electrode material, an organic compound composed of only an element having a small specific gravity, such as carbon or nitrogen, it has been expected to be developed as a large-capacity battery.

However, the conductive polymer has a property that excitons generated by an electrochemical oxidation-reduction reaction are delocalized over a wide range of a π-electron conjugated system and interact with each other. Since the concentration of excitons is limited, there is a problem that the capacity of the battery is limited.

Therefore, in the battery using such a conductive polymer as an electrode material, although a certain effect can be obtained in terms of reducing the weight of the battery, it is still insufficient in terms of increasing the capacity of the battery. Was.

On the other hand, a method for synthesizing an organic compound such as a polymer compound using a radical reaction has been developed, and is used for the development of various materials. However, the radical reaction is generally higher in reactivity than other chemical reactions and difficult to control, so that its application to an energy storage device such as a battery has not been studied.

Here, the radical reaction is a chemical reaction involving a radical, and particularly in the present invention,
It is defined to include both a reaction of generating a radical compound from a non-radical compound and a reaction of converting the generated radical compound into a non-radical compound in at least one of charging and discharging processes.

As described above, various types of batteries have been proposed in order to realize a large-capacity battery. However, batteries having high energy density, large capacity and excellent stability have not been established. Absent. In addition, studies on applying the above-described radical reaction to energy storage devices such as batteries have not been actively conducted because radical compounds are unstable.

[0014]

As described above, in a lithium ion battery using a transition heavy metal oxide as the active material of the positive electrode, it is difficult in principle to manufacture a large capacity battery due to the large specific gravity of the elements. Therefore, the present inventors have conducted intensive studies and as a result, by stabilizing the radical compound generated by the above radical reaction in at least one of the processes of charging and discharging, which are electrochemical oxidation-reduction reactions, It has been found that it can be used as an active material for energy storage devices such as. Therefore, an object of the present invention is to provide a battery having a high energy density, a large capacity and excellent stability by containing such a stabilized radical compound.

[0015]

According to the present invention, there is provided a battery comprising at least a positive electrode, a negative electrode, and an electrolyte, wherein at least one of a charging reaction and a discharging reaction involves a radical reaction. And a battery in which a radical compound generated by the radical reaction is stabilized. With this configuration,
In general, highly reactive and unstable radical compounds can be used effectively and easily, and irreversible side reactions of the generated radical compounds and chemical substances such as solvents and electrolytes contained in batteries are not possible. Since deterioration and decomposition can be suppressed, a battery having high energy density, large capacity, and excellent stability can be easily obtained.

In the present invention, a radical compound is defined as a chemical species having an unpaired electron, that is, a compound having a radical. Also, such radicals
Since the spin nuclear momentum is not zero, it has magnetic properties such as paramagnetism. Generally, radicals are generated by breaking chemical bonds of molecules by thermal decomposition, photolysis, radiolysis, electron transfer, etc., and have extremely high chemical reactivity and are generally unstable. Therefore, the reactivity is rapidly changed by the reaction between radicals or another stable molecule. The presence of such a radical can be observed by measurement such as an electron spin resonance spectrum (hereinafter, sometimes referred to as an ESR spectrum).

In the present invention, charge and discharge refer to electrochemical oxidation-reduction reactions, and generally, for an active material electrically connected to an electrode disposed in an electrolyte solution. Is defined as a reaction involving the transfer of electrons that proceeds when a voltage is applied or a load is applied to cause a short circuit. Therefore, the battery of the present invention that involves a radical reaction in at least one of the charging and discharging processes generates a radical compound by a reaction involving the transfer of electrons that proceeds when a voltage is applied to or short-circuits an active material. Defined as a battery.

In constituting the battery of the present invention,
It is preferable that the stabilized radical compound is an organic compound containing a structural unit represented by the following general formula (1) and / or general formula (2).

[0019]

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[In the general formula (1), the substituent R ¹ is a substituted or unsubstituted alkylene group, alkenylene group or arylene group, and X is an oxy radical group, a nitroxyl radical group, a sulfur radical group, a hydra group. It is a gall radical group, a carbon radical group, or a boron radical group. ]

[0021]

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[In the general formula (2), R ² and R ³ are mutually independent and are a substituted or unsubstituted alkylene group, alkenylene group or arylene group, and Y is a nitroxyl radical group or a sulfur radical group. , A hydrazyl radical group, or a carbon radical group. ]

With this configuration, the radical compound can be composed only of elements having a small mass such as carbon, hydrogen, oxygen, etc., so that a battery having a large energy density per unit mass can be easily obtained. be able to. Further, even when the stabilized radical compound is a polymer radical compound, the concentration of the reactive site can be increased by localizing unreacted unpaired electrons to radical atoms. Thus, a battery with a high energy density and a large capacity can be obtained.

In constituting the battery of the present invention,
Preferably, the stabilization of the radical compound is performed by a compound that interacts with the radical compound. By stabilizing in this way, in a radical reaction that proceeds in at least one process of charging and discharging, a side reaction is suppressed and the radical reaction proceeds smoothly, so that a large-capacity battery with excellent stability can be easily obtained. Can be.

In constituting the battery of the present invention,
The stabilization of the radical compound is preferably performed by embedding the radical compound in the host compound.
When stabilized, the radical compound generated in at least one of the charging and discharging processes is inactivated by the host compound as a whole, but the radical itself is transferred to the host compound, and the activity of the radical compound is reduced. Is still held, so that a large-capacity battery excellent in stability can be easily obtained.

In constituting the battery of the present invention,
It is preferable that the stabilization of the radical compound is performed by cooling. By stabilizing in this way, the reactivity of the radical compound generated in at least one of the charging and discharging processes can be controlled without changing the composition of the battery. Obtainable.

In constituting the battery of the present invention,
Preferably, the compound that interacts with the radical is an aromatic compound. With such a compound, a large-capacity battery excellent in stability can be easily obtained. In this case, the aromatic compound has a Hammett's substituent constant of 0.1.
The value is preferably in the range of 2 to 0.9.

In constituting the battery of the present invention,
The compound that interacts with the radical compound is preferably an acceptor solvent having an acceptor number within a range of 10 to 100. Even in the case of such a compound, a large-capacity battery excellent in stability can be easily obtained.

In constituting the battery of the present invention,
The compound that interacts with the radical compound is preferably a compound that forms a complex or dormant species with the radical compound.

In constituting the battery of the present invention,
The compound that forms a complex or a dormant species with the radical compound is preferably a Lewis acid compound, a transition metal, or a transition metal compound. Also in the case of such a compound, a large-capacity battery excellent in stability can be obtained more easily.

In constituting the battery of the present invention,
It is preferable that the spin concentration of the radical compound in the electron spin resonance spectrum is in a range of 10 ²⁰ to 10 ²³ spin / g. With such a configuration, a battery having high energy density, large capacity, and excellent stability can be easily obtained.

In constituting the battery of the present invention,
Such a battery is preferably a lithium ion secondary battery. With this configuration, a large-capacity battery with excellent stability can be obtained.

[0033]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a battery according to the present invention has a configuration in which, for example, as shown in FIG. 1, a negative electrode layer 1 and a positive electrode layer 2 are overlapped via a separator 5 containing an electrolyte. are doing. In the present invention, the active material used for the negative electrode layer 1 or the positive electrode layer 2 is a material that generates a radical compound by a radical reaction, and the generated radical compound is stabilized. The reason why the generated radical is stabilized to become an active material of the battery is considered to be because the stabilized radical can be further subjected to electrochemical oxidation and reduction. FIG. 2 shows a cross-sectional view of the stacked battery. In the structure, a negative electrode current collector 3, a negative electrode layer 1, a separator 5 containing an electrolyte, a positive electrode layer 2, and a positive electrode current collector 4 are sequentially stacked. It has a structure.

In the present invention, the method of laminating the positive electrode layer and the negative electrode layer is not particularly limited, and a multi-layered structure, a combination of the current collectors laminated on both sides, a wound material, and the like can be used. .

(1) Active Material Material 1 (Radical Compound) In the present invention, the kind of the radical compound is not particularly limited, but it is important in view of the effect of the invention and processability in forming the electrode active material layer. In particular, an organic compound containing a structural unit represented by the general formula (1) or (2) or any one of the general formulas is preferable.

Examples of such a radical compound include organic compounds such as an oxy radical compound, a nitroxyl radical compound, a nitrogen radical compound, a carbon radical compound, a boron radical compound, and a sulfur radical compound.

Specific examples of the oxy radical compound include, for example, aryloxy radical compounds represented by the following general formulas (3) to (5) and semiquinone radical compounds represented by the following general formula (6). .

[0038]

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[In the general formulas (3) to (6), R ^{4 to} R ⁸ are
Are independent of each other and are a hydrogen atom, a substituted or unsubstituted aliphatic or aromatic hydrocarbon group, a halogen atom, a hydroxyl group, a nitro group, a nitroso group, a cyano group, an alkoxy group, an aryloxy group, or an acyl group . ]

Specific examples of the nitroxyl radical compound include a radical compound having a piperidinoxy ring represented by the following general formula (7), a radical compound having a pyrrolidinoxy ring represented by the following general formula (8), A radical compound having a pyrrinoxy ring as in the formula (9) and a radical compound having a nitronyl nitroxide structure as in the following general formula (10) are exemplified.

[0041]

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In the general formulas (7) to (10), R ^{9 to} R ¹¹
Is the same as the contents of R ^{4 to} R ⁸ above. ]

Specific examples of the nitrogen radical compound include a radical compound having a trivalent hydrazyl group represented by the following general formula (11) and a trivalent feldazyl group represented by the following general formula (12). Examples include a radical compound, a radical compound having a tetravalent ferdazyl group represented by the following general formula (13), and a radical compound having an aminotriazine structure represented by the following general formula (14).

[0044]

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[In the general formulas (11) to (14), R ^{12 to} R
²⁴ is the same as the contents of R ^{4 to} R ⁸ . ]

In the present invention, the production of a battery using the above-mentioned radical compound as the active material of the electrode as it is may be performed by converting the radical compound into the above-mentioned radical compound in one of the charging reaction and the discharging reaction. A battery can also be manufactured using the non-radical compound.

Material 2 In the present invention, a material that generates a radical compound in the course of a charge / discharge reaction can be used as an active material for a positive electrode, a negative electrode, or any one of the electrodes, but from the viewpoint of energy density, In particular, it is preferable to use the active material as a positive electrode active material.

When these materials are used as an active material of one of the positive electrode and the negative electrode, the following materials can be used as the active materials of the other electrodes. That is, when a material that generates a radical compound is used as the active material of the negative electrode layer, metal oxide particles, a disulfide compound, a conductive polymer, or the like is used as the active material of the positive electrode layer. Here, as the metal oxide,
For example, LiMnO ₂ , Li _x Mn ₂ O ₄ (0 <x <
2) Lithium manganate or lithium manganate having a spinel structure, such as MnO ₂ , LiCoO ₂ , L
iNiO ₂ or Li _x V ₂ O ₅ (0 <x <2),
As disulfide compounds, dithioglycol, 2,2
5-dimercapto-1,3,4-thiadiazole, S-
Triazine-2,4,6-trithiol and the like, and examples of the conductive polymer include polyacetylene, polyphenylene, polyaniline, and polypyrrole. In the present invention, these positive electrode layer materials can be used alone or in combination of two or more.
It is also preferable to use a conventionally known active material as a composite active material by mixing these materials.

On the other hand, when a material that generates a radical compound is used as the active material of the positive electrode layer, graphite, amorphous carbon, lithium metal,
One kind alone or a combination of two or more kinds such as a lithium alloy, lithium ion storage carbon, and a conductive polymer is used. The shape is not particularly limited. For example, in addition to a thin film of lithium metal, a bulk metal, a solidified powder, a fiber, a flake, and the like can be used.

(2) Stabilization of Radical Compound In the present invention, the method of stabilizing the radical compound is not particularly limited, and a conventionally known method is used. A method using a compound that acts, a method of embedding a radical compound in a host compound, a method of cooling, and the like are used.

In the present invention, a compound that interacts with a radical compound is a compound that forms various chemical bonds such as a covalent bond, a hydrogen bond, a coordination bond, a hydrophobic bond, and a van der Waals bond with the radical compound. A compound in which the free energy of reaction ΔG is negative. Such a compound is not particularly limited as long as it is a compound that stabilizes a radical compound, but in particular, an aromatic compound, an acceptor solvent, and a radical compound and a complex or a dormant compound for ease of carrying out the invention. Seed-forming compounds are preferred.

Among them, the aromatic compound preferably has a substituent having a substituent constant within the range of 0.2 to 0.9 in the Hammett formula shown below. The reason for this is that when the substituent constant is less than 0.2, the generated radical compound is insufficiently stabilized, and unnecessary side reactions may proceed. On the other hand, when the substituent constant is less than 0.2.
If it exceeds 9, the radical compound undergoes excessive stabilization, which may hinder reversible charge / discharge reactions.

Here, the Hammett's substituent constant means the reaction rate constants of a compound having no substituent and a compound having a substituent in the meta- or para-substituted aromatic compound as k ₀ and k, respectively. Is defined as σ in the following Hammett equation log (k / k ₀ ) = ρσ. In the Hammett equation,
The dissociation reaction of benzoic acid and its derivatives in an aqueous solution at 25 ° C. is defined as ρ = 1.

Examples of such substituents include, for example, -OC ₆ H ₅ , -NHCOCH ₃ , -SH, -OC
_{OCH 3, -F, -Cl, -Br} , -CHO, -OCF
_{3, -CONH 2, -SCOCH 3,} -COOH, -C
One type alone or a combination of two or more types such as OCH ₃ , —CF ₃ , —CN, and —NO _{2 is} exemplified. In addition,
As these substituents, -F, -Cl, -Br and -CN are particularly preferred.

As the acceptor solvent, a solvent having an acceptor number within a range of 10 to 100 is preferable. The reason is that if the number of acceptors is less than 10,
This is because stabilization of the generated radical compound becomes insufficient and unnecessary side reactions may proceed.On the other hand, when the number of acceptors exceeds 100, the radical compound undergoes excessive stabilization, so that reversible This is because a complicated charge / discharge reaction may be hindered. Here, the number of acceptors is defined as the number of acceptors, with hexane as one standard solvent and the number of acceptors defined as 0, and a solution of triethylphosphine oxide / antimony pentachloride in 1,2-dichloroethane as the other standard solvent. Is defined as a dimensionless number given as the relative chemical shift of ³¹ P-NMR of triethylphosphine oxide in the solvent of interest when is defined as 100.

Examples of such an acceptor solvent include dioxane, acetone, N-methylpyrrolidone,
Dimethylacetamide, pyridine, nitrobenzene, benzonitrile, dimethylformamide, ethylene carbonate,
Dichloroethylene carbonate, propylene carbonate, 1,2-carbonate
One type of butylene, acetonitrile, dimethylsulfoxide, dichloromethane, nitromethane, 2-propanol, ethanol, methanol and the like, or a combination of two or more types may be mentioned.

In the present invention, the compound which forms a complex with the radical compound may be a group formed with the radical compound by bonding a ligand around an atom or ion of a metal or a metal-like element. Compounds. A dormant species is a stable chemical species also called a dormant species in a radical reaction. That is, the compound that forms a dormant species in the present invention is defined as a compound that forms a covalent bond with a radical compound, is temporarily converted to a stable compound, and can regenerate the radical compound under appropriate conditions. Is done.

The compound which forms a complex or a dormant species with such a radical compound is not particularly limited as long as it is a compound included in the above definition, but in particular, Lewis acid compound, transition metal, Alternatively, transition metal compounds are preferred. In the present invention, the abundance of various compounds for stabilizing radicals is not particularly limited, but it is desirable to have at least as many stabilizing agents as the number of generated radicals from the viewpoint of stabilizing effect.

In the present invention, the concentration of the generated radical is not particularly limited, but a preferred value is 10 ²⁰ to
Preferably, the value is in the range of 10 ²³ spin / g.
The reason for this is that when the radical concentration is less than 10 ²⁰ spin / g, the capacity of the battery becomes small, and the effect of the present invention of increasing the capacity of the battery may not be obtained. On the other hand, if the radical concentration exceeds 10 ²³ spin / g, it may be difficult to form a stable battery.

(3) Binder In the present invention, in order to strengthen the binding between the constituent materials,
Binders can also be used. Examples of such a binder include polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-tetrafluoroethylene copolymer, styrene-butadiene copolymer rubber, polypropylene, polyethylene, polyimide, and various polyurethanes. And the like.

(4) Catalyst In the present invention, a catalyst that promotes the oxidation-reduction reaction can be used in order to carry out the electrode reaction more lubricatingly. Examples of such a catalyst include conductive polymers such as polyaniline, polypyrrole, polythiophene, polyacetylene, and polyacene; basic compounds such as pyridine derivatives, pyrrolidone derivatives, benzimidazole derivatives, benzothiazole derivatives, and acridine derivatives; and metal ion complexes. Is mentioned.

(5) Current Collector The current collector in the present invention is formed of a conductor,
The charge generated from the battery electrode is collected.
In the present invention, as the negative electrode current collector 3 and the positive electrode current collector 4, nickel, aluminum, copper, gold, silver, an aluminum alloy,
And a metal foil such as stainless steel, a metal flat plate, a mesh electrode, a carbon electrode, and the like. Further, such a current collector may have a catalytic effect, or the active material and the current collector may be chemically bonded.

(6) Separator and Sealing Agent The separator 5 in the present invention prevents the positive electrode layer and the negative electrode layer from coming into contact with each other, and may be made of a material such as a porous film or a nonwoven fabric. Further, such a separator is preferably configured to include an electrolyte. However, when an ion conductive polymer is used as the electrolyte, the separator itself can be omitted. Also, the sealing material 6 in the present invention is not particularly limited, and a conventionally known material used for the exterior of the battery is used.

(7) Electrolyte In the present invention, the electrolyte transports the charge carrier between the two electrodes of the negative electrode layer 1 and the positive electrode layer 2 and generally has a capacity of 1 at room temperature.
And a 0 ^-5 -10 ion conductive ^-1 S / cm. In the present invention, for example, an electrolyte solution in which an electrolyte salt is dissolved in a solvent can be used as the electrolyte. Such electrolyte salts include, for example, LiPF ₆ , LiClO
₄ , LiBF ₄ , LiCF ₃ SO ₃ , Li (CF ₃ SO
₂ ) ₂ N, Li (C ₂ F ₅ SO ₂ ) ₂ N, Li (CF ₃ SO
₂ ) ₃ C, a conventionally known material such as Li (C ₂ F ₅ SO ₂ ) ₃ C can be used.

As the solvent for the electrolyte salt, for example,
Organic solvents such as ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, γ-butyrolactone, tetrahydrofuran, dioxolan, sulfolane, dimethylformamide, dimethylacetamide, and N-methyl-2-pyrrolidone can be used. In the present invention, these solvents can be used alone or as a mixed solvent of two or more.

Further, in the present invention, a solid electrolyte can be used as the electrolyte. Examples of the polymer compound used for such a solid electrolyte include polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-ethylene copolymer, vinylidene fluoride-monofluoroethylene copolymer, and fluoropolymer. Vinylidene fluoride polymers such as vinylidene fluoride-trifluoroethylene copolymer, vinylidene fluoride-tetrafluoroethylene copolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, and acrylonitrile-methyl Methacrylate copolymer, 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, further polyethylene oxide, ethylene oxide - propylene oxide copolymers, and polymers of these acrylates body or methacrylate body thereof. The solid electrolyte may be a gel formed by adding an electrolytic solution to these polymer compounds, or may be used alone with the polymer compound alone.

(8) Shape Also, the shape of the battery is not particularly limited, and it can be applied to shapes such as a cylindrical battery, a coin battery, a prismatic battery, a film battery, and a button battery.

[0068]

EXAMPLES Hereinafter, the present invention will be described more specifically, but the present invention is not limited to these examples.

Example 1 (1) Production of Battery In a dry box equipped with a gas purifier, 50 mg of galvinoxyl radical represented by the following formula (15) was placed in a glass container under an argon gas atmosphere. 60 mg of graphite powder was mixed as an auxiliary conductive material, and 20 ml of a vinylidene fluoride-hexafluoropropylene copolymer was added thereto.
g and 1 g of tetrahydrofuran were further added and mixed for several minutes until the whole became uniform, whereby a black slurry was obtained. Next, when the ESR spectrum of the slurry containing the galvinoxyl radical (15) was measured, the spin concentration was 10 ²¹ spin / g or more.

[0070]

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Subsequently, 200 mg of the obtained slurry was
Aluminum foil with lead wire (Area: 1.5cm ×
(1.5 cm, thickness: 100 μm), developed with a wire bar so as to have a uniform thickness throughout, and allowed to stand at room temperature for 60 minutes. An electrode layer containing noxyl radical was formed.

Next, 600 mg of vinylidene fluoride-hexafluoropropylene copolymer and 1 mol / l of Li
Acceptor containing PF ₆ as the electrolyte salt - the number 18.9
Was mixed with 1,400 mg of an electrolytic solution composed of a propylene carbonate solution, and 11.3 g of tetrahydrofuran was further added thereto, followed by stirring at room temperature. After the vinylidene fluoride-hexafluoropropylene copolymer is dissolved, this solution is applied on a stepped glass plate, allowed to stand at room temperature for 1 hour to dry tetrahydrofuran naturally, and a 1 mm-thick gel electrolyte membrane. Was obtained.

Next, the aluminum foil on which the electrode layer containing galvinoxyl radicals was formed was placed on a 2.0 cm × 2.0 c
m, the gel electrolyte membrane cut into layers is laminated, and further, a lithium-bonded copper foil (with a lithium film thickness of 30) having a lead wire is provided.
μm, and a copper foil thickness of 20 μm), the whole was sandwiched between polytetrafluoroethylene sheets having a thickness of 5 mm, and pressure was applied to produce a battery.

(2) Evaluation of Battery Using the battery prepared as described above as a sample, discharging was performed at a constant current of 0.1 mA using an electrode layer containing galvinoxyl radical as a positive electrode and a lithium-bonded copper foil as a negative electrode. .
As a result, a voltage flat portion was observed around 2.3 V, and it was confirmed that the battery operated. Further, when the battery was repeatedly charged and discharged, it was confirmed that the battery could be charged and discharged for 10 cycles or more and operated as a secondary battery.

Example 2 (1) Production of Battery Instead of the galvinoxyl radical (15) in Example 1,
2,6-dimethyl-α- (3,5-dimethyl-4-oxo-2,5-cyclohexadiene-1-ylidene) -p
-A black slurry was obtained in the same manner as in Example 1 except that the toloxy radical (16) was used. When the ESR spectrum of this slurry was measured, the spin concentration was 10 ²¹ spin / g or more.

[0076]

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Subsequently, 200 mg of the obtained slurry was
Aluminum foil with lead wire (Area: 1.5cm ×
1.5 cm, thickness: 100 μm), developed and dried in the same manner as in Example 1, and dried on an aluminum foil by 2,6-dimethyl-α- (3,5-dimethyl-4-oxo). -2,5-cyclohexadiene-1-ylidene)-
An electrode layer containing p-tolyloxy radical was formed.

Next, the gel electrolyte membrane used in Example 1 cut into 2.0 cm × 2.0 cm was laminated on the aluminum foil on which the electrode layer was formed, and the lithium-bonded copper foil was produced in the same manner as in Example 1. Were overlapped, sandwiched between polytetrafluoroethylene sheets and pressure was applied to produce a battery.

(2) Evaluation of Battery Using the battery prepared as described above as a sample, discharging was performed in the same manner as in Example 1. As a result, a voltage flat portion was observed around 2.1 V, and it was confirmed that the battery operated. Further, when the battery was repeatedly charged and discharged, it was confirmed that the battery operated as a secondary battery capable of being charged and discharged over 10 cycles or more.

(Comparative Example 1) (1) Preparation of Battery From a vinylidene fluoride-hexafluoropropylene copolymer (600 mg) and a diethyl carbonate solution having an acceptor number of 2.6 containing 1 mol / l of LiPF ₆ as an electrolyte salt. The resulting solution was mixed with 1,500 mg of an electrolytic solution, and 500 mg of tetrahydrofuran was further added, followed by stirring at room temperature. After the vinylidene fluoride-hexafluoropropylene copolymer is dissolved, it is applied on a glass plate with a step, left at room temperature for 1 hour to dry tetrahydrofuran naturally, and a gel electrolyte membrane cast film with a thickness of 1 mm I got

Next, a gel electrolyte membrane cut into 2.0 cm × 2.0 cm was laminated on an aluminum foil having the same electrode layer as in Example 2, and a lithium-bonded copper foil was produced in the same manner as in Example 1. Were overlapped, sandwiched between polytetrafluoroethylene sheets and pressure was applied to produce a battery.

(2) Evaluation of Battery Using the battery prepared as described above as a sample, discharge was performed in the same manner as in Example 1. As a result, it was found that the voltage decreased without showing a flat portion, and the battery did not operate.

Example 3 (1) Preparation of Radical Compound 1,3,5-Trisdiazo-cyclohexane-
The powder of 2,4,6-trione was added, the temperature was raised to 600 ° C. under vacuum, kept at the same temperature for 20 hours, and then cooled to room temperature to obtain a product. Next, when the NMR spectrum and IR spectrum of this product were measured, it was presumed that its molecular structure was a network-like polyoxy radical.
Further, when the ESR spectrum was measured, the spin concentration of the obtained product was 8 × 10 ²¹ spin / g.

(2) Preparation of Battery A black slurry was prepared in the same manner as in Example 1 except that the network-like polyoxy radical prepared in (1) was used instead of the galvinoxyl radical of Example 1. Obtained.
Subsequently, 200 mg of the obtained slurry was applied to an aluminum foil with a lead wire (area: 1.5 cm × 1.5 cm,
(Thickness: 100 μm) was dropped onto the surface, developed and dried in the same manner as in Example 1, and an electrode layer containing a network-like polyoxy radical was formed on an aluminum foil.

Next, the aluminum foil on which the electrode layer was formed was cut into 2.0 cm × 2.0 cm and had a thickness of 25 μm.
After laminating a lithium-bonded copper foil in the same manner as in Example 1 and connecting leads, the porous polyethylene film has a nitrile group having a Hammett's substituent constant of 0.65, and has an acceptor. An electrolyte containing benzonitrile as a solvent having a number of 15.5 and 1 mol / l of LiBF ₄ was added, and the whole was packaged with a laminate film.
A battery was manufactured.

(3) Evaluation of Battery Using the battery prepared as described above as a sample, discharging was performed in the same manner as in Example 1. As a result, a voltage flat portion was observed at around 2.0 V, and it was confirmed that the battery operated. Further, when this battery was repeatedly charged and discharged, it was confirmed that the battery operated as a secondary battery capable of being charged and discharged over 10 cycles or more.

Comparative Example 2 (1) Production of Battery The porous polyethylene film used in Example 3 was laminated on an aluminum foil on which an electrode layer was formed in the same manner as in Example 3, and the same as in Example 1. After laminating the copper foil with lithium bonding by the method and connecting the leads, dimethyl carbonate which is a solvent having an acceptor number of 3.6 and 1 mol / l of Li
An electrolytic solution containing BF ₄ was added, and the whole was packaged with a laminate film to prepare a battery.

(2) Evaluation of Battery Using the battery prepared as described above as a sample, discharging was performed in the same manner as in Example 1. As a result, it was found that the voltage decreased without showing a flat portion, and the battery did not operate.

Example 4 (1) Production of Battery The porous polyethylene film used in Example 3 was laminated on an aluminum foil on which an electrode layer was formed in the same manner as in Example 3, and the same as in Example 1. Lithium-bonded copper foil was overlapped by the method, and the leads were connected. Subsequently, chlorobenzene-containing benzene having a Hammett's substituent constant of 3.7 and 1
An electrolyte containing mol / l of LiCl ₄ was added, and the whole was packaged with a laminate film to prepare a battery.

(2) Evaluation of Battery Using the battery prepared as described above as a sample, discharging was performed in the same manner as in Example 1. As a result, a voltage flat portion was observed at around 2.0 V, and it was confirmed that the battery operated. Further, when the battery was repeatedly charged and discharged, it was confirmed that the battery operated as a secondary battery capable of being charged and discharged over 10 cycles or more.

Example 5 (1) Preparation of Radical Compound Polyvinyl dimethyl phenol was dissolved in tetrahydrofuran and reacted with potassium ferricyanide. next,
The reaction solution was evaporated to dryness, and the product obtained by sublimation purification was measured for NMR spectrum and IR spectrum. As a result, the molecular structure was presumed to be a reticulated polyvinyldimethylphenoxy radical (17). Also,
When the ESR spectrum of the obtained (17) was measured, its spin concentration was 8.5 × 10 ²¹ spin / g.

[0092]

Embedded image

(2) Preparation of Battery The above (1) was used in place of the galvinoxyl radical of Example 1.
A black slurry was obtained in the same manner as in Example 1, except that the network-like polyvinyl dimethylphenoxy radical obtained in the above was used. Subsequently, 200 mg of the obtained slurry was applied to an aluminum foil (area: 1.5 cm ×
The solution was developed and dried in the same manner as in Example 1 to form an electrode layer containing a reticulated polyvinyldimethylphenoxy radical on an aluminum foil.

Next, 2.0 μm was applied to the aluminum foil on which the electrode layer containing the polyvinyl dimethylphenoxy radical was formed.
A 25 μm thick porous polyethylene film cut into cm × 2.0 cm was laminated, lithium-laminated copper foil was laminated by the method of Example 1, and leads were connected.
An electrolyte solution containing methyl isopropyl carbonate, a solvent having an acceptor number of 5.3, and 1 mol / l of LiBF ₄ was added, and 0.25 mol of iodine powder was further added as a Lewis acid. A battery was manufactured.

(3) Evaluation of Battery Using the battery prepared as described above as a sample, discharging was performed in the same manner as in Example 1. As a result, a voltage flat portion was observed at around 2.5 V, and it was confirmed that the battery operated. Further, when the battery was repeatedly charged and discharged, it was confirmed that the battery operated as a secondary battery capable of being charged and discharged over 10 cycles or more.

Example 6 (1) Production of Battery An aluminum foil having an electrode layer similar to that of Example 5 was formed on an aluminum foil.
The porous polyethylene films used in Example 3 were laminated, and a lithium-bonded copper foil was laminated in the same manner as in Example 1, and leads were connected. Then, acceptor
1m with methyl isopropyl carbonate, a solvent whose number is 5.3
An electrolytic solution containing ol / l LiBF ₄ was added, and 0.05 mol of a tetramesitylporphyrin cobalt (III) complex was further added. The whole was packaged with a laminate film to prepare a battery.

(2) Evaluation of Battery Using the battery prepared as described above as a sample, discharge was performed in the same manner as in Example 1. As a result, a voltage flat portion was observed at around 2.0 V, and it was confirmed that the battery operated. Further, when the battery was repeatedly charged and discharged, it was confirmed that the battery operated as a secondary battery capable of being charged and discharged over 10 cycles or more.

Comparative Example 3 The porous polyethylene film used in Example 3 was laminated on an aluminum foil having the same electrode layer as in Example 5, and a lithium-bonded copper foil was produced in the same manner as in Example 1. They were superposed and the leads were connected. Subsequently, an electrolyte solution containing methyl isopropyl carbonate, which is a solvent having an acceptor number of 5.3, and 1 mol / l of LiBF ₄ was added, and the whole was packaged with a laminate film without adding a Lewis acid or a complex. Produced.

(2) Evaluation of Battery Using the battery prepared as described above as a sample, discharging was performed in the same manner as in Example 1. As a result, it was found that the voltage decreased without showing a flat portion, and the battery did not operate.

Example 7 (1) Production of Battery An aluminum foil having an electrode layer similar to that of Example 5 was formed on an aluminum foil.
The porous polyethylene films used in Example 3 were laminated, and a lithium-bonded copper foil was laminated in the same manner as in Example 1, and leads were connected. Then, acceptor
1m with methyl isopropyl carbonate, a solvent whose number is 5.3
An electrolytic solution containing ol / l LiBF ₄ was added, and the whole was packaged with a laminate film without adding a Lewis acid or a complex, thereby producing a battery.

(2) Evaluation of Battery Next, the obtained battery was cooled to −50 ° C. using a dry ice / acetone bath, and then discharged in the same manner as in Example 1. As a result, a voltage flat portion was observed at around 2.0 V, and it was confirmed that the battery operated. Further, when the battery was repeatedly charged and discharged, it was confirmed that the battery operated as a secondary battery capable of being charged and discharged over 10 cycles or more.

Example 8 (1) Production of Battery 1 mol / l of L was added to 600 mg of polyacrylonitrile.
3.8 acceptors containing iPF ₆ as electrolyte salt
After mixing 1,500 mg of an electrolytic solution consisting of a dibutyl carbonate solution of above, the solution was heated to 110 ° C. and dissolved, and then spread on a stepped glass plate, cooled to room temperature, and cast as an electrolyte membrane. I got

Next, a gel electrolyte membrane cut into 2.0 cm × 2.0 cm was laminated on an aluminum foil on which an electrode layer similar to that of Example 5 was formed. Were overlapped, sandwiched between polytetrafluoroethylene sheets and pressure was applied to produce a battery.

(2) Evaluation of Battery Using the battery prepared as described above as a sample, discharging was performed in the same manner as in Example 1. As a result, a voltage flat portion was observed at around 2.0 V, and it was confirmed that the battery operated. Further, when the battery was repeatedly charged and discharged, it was confirmed that the battery operated as a secondary battery capable of being charged and discharged over 10 cycles or more. Also, when the ESR spectrum of the gel electrolyte was measured before and after charging and discharging,
The spin concentration was high after discharging and low after charging. From these results, it was suggested that the gel composed of polyacrylonitrile was a host compound for embedding generated radicals.

Example 9 (1) Production of Battery Instead of the galvinoxyl radical of Example 1, 2, 2,
A black slurry was obtained in the same manner as in Example 1 except that 6,6-tetramethylpiperidine-1-oxyl was used. The ESR of the slurry containing 2,2,6,6-tetramethylpiperidine-1-oxyl radical used
When the spectrum was measured, the spin concentration was 10 ²¹
Spin / g or more.

Subsequently, 200 mg of the obtained slurry was
Aluminum foil with lead wire (Area: 1.5cm ×
An electrode containing 2,2,6,6-tetramethylpiperidine-1-oxyl on an aluminum foil was developed and dried in the same manner as in Example 1 and dropped onto a surface of 1.5 cm, thickness: 100 μm). A layer was formed. Next, 2,2,6,6-
2.0 cm × 2.times. On an aluminum foil on which an electrode layer containing tetramethylpiperidine-1-oxyl radical was formed.
The gel electrolyte membrane used in Example 1, which was cut into 0 cm, was laminated, lithium-bonded copper foils were overlapped in the same manner as in Example 1, and pressure was applied by sandwiching between polytetrafluoroethylene sheets to produce a battery. .

(2) Evaluation of Battery Using the battery prepared as described above as a sample, discharging was performed in the same manner as in Example 1. As a result, a voltage flat portion was observed around 3.1 V, and it was confirmed that the battery was operating. Further, when the battery was repeatedly charged and discharged, it was confirmed that the battery operated as a secondary battery capable of being charged and discharged over 10 cycles or more.

Example 10 (1) Production of Battery Instead of the galvinoxyl radical of Example 1, 2,2-
A black slurry was obtained in the same manner as in Example 1, except that diphenyl-1-picrylhydrazyl radical was used. When the ESR spectrum of the used 2,2-diphenyl-1-picrylhydrazyl radical was measured as a sample, the spin concentration was 10 ²¹ spin / g or more.

Subsequently, 200 mg of the obtained slurry was applied to an aluminum foil (area: 1.5 cm ×
(1.5 cm, thickness: 100 μm), developed and dried in the same manner as in Example 1 to form an electrode layer containing 2,2-diphenyl-1-picrylhydrazyl radical on an aluminum foil. Formed. Next, on the aluminum foil on which the electrode layer containing 2,2-diphenyl-1-picrylhydrazyl radical was formed, the gel electrolyte membrane used in Example 1 cut into 2.0 cm × 2.0 cm was laminated, In the same manner as in Example 1, lithium-bonded copper foils were laminated, sandwiched between polytetrafluoroethylene sheets, and pressed to produce a battery.

(2) Evaluation of Battery Using the battery prepared as described above as a sample, discharge was performed in the same manner as in Example 1. As a result, a voltage flat portion was observed at around 2.2 V, and it was confirmed that the battery operated. Further, when the battery was repeatedly charged and discharged, it was confirmed that the battery operated as a secondary battery capable of being charged and discharged over 10 cycles or more.

Example 11 (1) Production of Battery A black slurry was obtained in the same manner as in Example 1 except that tetraethylthiuram disulfide was used instead of the galvinoxyl radical of Example 1. In addition, after heating the tetraethylthiuram disulfide used here to 80 ° C.,
When the ESR spectrum was measured, the spin concentration was 10 ²¹ spin / g or more. From this, it was presumed that tetraethylthiuram disulfide generates a radical at 80 ° C.

Subsequently, 200 mg of the obtained slurry was applied to an aluminum foil (area: 1.5 cm ×
(1.5 cm, thickness: 100 μm), developed in the same manner as in Example 1, and dried to form an electrode layer containing tetraethylthiuram disulfide on an aluminum foil. Next, the aluminum foil on which the electrode layer containing tetraethylthiuram disulfide was formed was placed at 2.0 cm ×
The gel electrolyte membrane used in Example 1, which was cut into 2.0 cm, was laminated, lithium-bonded copper foils were laminated in the same manner as in Example 1, and pressure was applied by sandwiching the sheets with a polytetrafluoroethylene sheet. Produced.

(2) Evaluation of Battery The battery prepared as described above was used as a sample, heated to 80 ° C., and discharged in the same manner as in Example 1. as a result,
A voltage flat portion was observed around 2.3 V, and it was confirmed that the battery operated. Further, when the battery was repeatedly charged and discharged, it was confirmed that the battery operated as a secondary battery capable of being charged and discharged over 10 cycles or more.

[0114]

According to the present invention, at least the positive electrode, the negative electrode, and the electrolyte are constituent elements, and the radical compound generated in at least one of the charging and discharging processes is stabilized, so that the energy at the time of charging and discharging the battery can be improved. The density and the capacity can be increased, and the stability and safety can be improved.

[Brief description of the drawings]

FIG. 1 is a front sectional view showing one embodiment of a secondary battery of the present invention.

FIG. 2 is a central longitudinal sectional view showing one embodiment of a secondary battery of the present invention.

[Explanation of symbols]

 Reference Signs List 1 negative electrode layer 2 positive electrode layer 3 negative electrode current collector 4 positive electrode current collector 5 separator including electrolyte layer 6 sealing material

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yukiko Morioka 5-7-1 Shiba, Minato-ku, Tokyo Inside NEC Corporation (72) Inventor Kentaro Nakahara 5-7-1 Shiba, Minato-ku, Tokyo Japan Inside Electric Company (72) Inventor Hiroshi Sakauchi 5-7-1 Shiba, Minato-ku, Tokyo NEC Corporation F-term (Reference) 5H029 AJ03 AJ12 AK02 AK03 AK15 AK16 AK18 AL06 AL07 AL08 AL12 AL15 AL16 AL18 AM00 AM02 AM03 AM04 AM05 AM07 AM16 CJ02 EJ03 EJ11 EJ12 HJ00 5H050 AA08 AA15 BA17 CA05 CA08 CA09 CA19 CA21 CA22 CA25 CA26 CA29 CB07 CB08 CB09 CB12 CB19 CB20 CB29 DA17 DA18 EA26 GA02 GA15 HA00

Claims (12)

[Claims] 1. A battery comprising at least a positive electrode, a negative electrode, and an electrolyte and having a radical reaction in at least one of charging and discharging processes, wherein a radical compound generated by the radical reaction is stabilized. Battery. 2. The method according to claim 1, wherein the radical compound is an organic compound containing a structural unit represented by the following general formula (1) and / or (2). battery. Embedded image [In the general formula (1), the substituent R ¹ is a substituted or unsubstituted alkylene group, alkenylene group, or arylene group, and X is an oxy radical group, a nitroxyl radical group, a sulfur radical group, or a hydrazyl radical group. , A carbon radical group, or a boron radical group. ] [In the general formula (2), R ² and R ³ are mutually independent and are a substituted or unsubstituted alkylene group, alkenylene group, or arylene group, and Y is a nitroxyl radical group, a sulfur radical group, or hydrazyl. It is a radical group or a carbon radical group. ] 3. The battery according to claim 1, wherein the stabilization of the radical compound is performed by a compound that interacts with the radical compound. 4. The battery according to claim 1, wherein the stabilization of the radical compound is performed by embedding the radical compound in a host compound. 5. The battery according to claim 1, wherein the stabilization of the radical compound is performed by cooling. 6. The battery according to claim 3, wherein the compound interacting with the radical compound is an aromatic compound. 7. The battery according to claim 6, wherein a substituent constant of the substituent on the aromatic compound in the Hammett equation is in a range of 0.2 to 0.9. 8. The battery according to claim 3, wherein the compound that interacts with the radical compound is an acceptor solvent having an acceptor number within a range of 10 to 100. 9. The battery according to claim 3, wherein the compound that interacts with the radical compound is a compound that forms a complex or a dormant species with the radical compound. 10. The battery according to claim 9, wherein the compound that forms a complex or a dormant species with the radical compound is a Lewis acid compound, a transition metal, or a transition metal compound. 11. The spin concentration of the radical compound in an electron spin resonance spectrum of the radical compound is in the range of 10 ²⁰ to 10 ²³ spin / g.
The battery according to claim 10. 12. The battery according to claim 1, wherein the battery is a lithium ion secondary battery.