JP2010118320A - Secondary battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an active material having high energy density and capable of improving cycle characteristics, and to provide a secondary battery using the same. <P>SOLUTION: In the secondary battery, which has a positive electrode and a negative electrode, at least one of the positive electrode and the negative electrode has a copolymer of an organic redox compound having a substituent capable of multi-dentation and a metal complex in which metal atoms are bonded. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a secondary battery having high output and high energy density and excellent charge / discharge cycle characteristics, and more particularly to a secondary battery having a redox compound in a positive electrode and / or a negative electrode.

  With the rapid market expansion of portable electronic devices such as notebook computers and mobile phones, there is an increasing demand for small high-capacity secondary batteries with high energy density used for these. In order to meet this demand, a secondary battery using an alkali metal ion such as lithium ion as a charge carrier and utilizing an electrochemical reaction accompanying charge transfer has been developed.

  In recent years, studies have been made on using an organic compound as an electrode material in order to produce a lighter battery having a higher energy density.

  However, an electrode using an organic compound as an active material can realize a light weight characteristic, but has a problem in repeated charge / discharge characteristics. The reason for this is that, for example, when tetrathiafulvalene is used as the organic compound, when the charge / discharge reaction proceeds, electrons are removed and become cations, forming an anion and a salt of the electrolytic solution, increasing the solubility, There is a problem that the cycle characteristics deteriorate due to elution. For this reason, there have been reports of insolubilizing organic compounds such as support and polymerization on metals and carbon materials, and suppression of elution by providing an ionic group in the substrate. (For example, see Patent Documents 1 and 2)

However, measures such as loading on a base material such as a conductive material or introducing a base material having an ionic group reduces the weight ratio of the active material. In addition, when polymerized, the bulk specific gravity becomes low, so the capacity around the volume decreases. Therefore, an active material having high energy density and good cycle characteristics and a secondary battery including the active material have not been obtained yet.
JP 2004-111374 A JP 2007-265712 A

  The present invention has been made in view of the above circumstances, and an object thereof is to provide an active material having a high energy density and capable of improving cycle characteristics, and a secondary battery using the active material.

  In order to solve the above-mentioned problems, the present inventors have conducted intensive studies, and as a positive electrode or a negative electrode active material for a secondary battery, have a copolymer of an organic redox compound and a metal complex in the positive electrode and / or the negative electrode. It was found that the above problems can be solved.

  That is, the secondary battery of the present invention according to claim 1 is a secondary battery having a positive electrode and a negative electrode, wherein at least one of the positive electrode and the negative electrode has an organic redox compound having a substituent capable of multidentate coordination, and a metal It has a copolymer with a metal complex to which atoms are bonded.

  The secondary battery of the present invention according to claim 1 has an organic redox compound in at least one of the positive electrode and the negative electrode. The organic redox compound is a substance having a battery capacity and functions as an electrode active material. And since an organic redox compound is contained in an electrode as a copolymer with a metal complex, even if electrons are removed from the organic redox compound by an electrode reaction, elution into the electrolyte is suppressed due to the bulkiness of the copolymer. The As a result, the cycle characteristics of the secondary battery of the present invention are improved.

  A secondary battery according to a second aspect of the present invention is the secondary battery according to the first aspect, wherein the organic redox compound is tetrathiafulvalene represented by the following chemical formula 13 or a derivative thereof.

(Each of R1 to R4 in the formula 13 is a chain or cyclic aliphatic group, and at least two of the R1 to R4 are nitrile groups capable of coordinating with a metal or the following formula 14 or (It can have a substituent represented by the formula.)

（化１４式及び化１５式中のＸ及びＹは、酸素、窒素、リン、硫黄が含まれる１５，１６族より選ばれる元素であり、中性でも負電荷を帯びていてもよく、Ｒ５〜Ｒ７のそれぞれは、鎖状または環状の脂肪族基、あるいは水素であり、鎖状または環状の脂肪族基は、酸素、窒素、硫黄、珪素、リン及びホウ素よりなる群から選ばれる1種以上を含むことができる。）
請求項２によると、有機レドックス化合物がテトラチアフルバレン又はその誘導体となっており、請求項１の効果を発揮できる。

(X and Y in the chemical formula 14 and chemical formula 15 are elements selected from the group 15 and 16 containing oxygen, nitrogen, phosphorus and sulfur, and may be neutral or negatively charged. Each of R7 is a chain or cyclic aliphatic group or hydrogen, and the chain or cyclic aliphatic group is one or more selected from the group consisting of oxygen, nitrogen, sulfur, silicon, phosphorus and boron. Can be included.)
According to claim 2, the organic redox compound is tetrathiafulvalene or a derivative thereof, and the effect of claim 1 can be exhibited.

A secondary battery according to a third aspect of the present invention is the secondary battery according to the second aspect, wherein the organic redox compound is such that X and Y in the chemical formula 2 form a chemical bond with the metal complex, and in the charge / discharge process. There is no change in formal charge.
According to claim 3, X and Y of claim 2 form a chemical bond with the metal complex, and the effects of claims 1 and 2 can be exhibited because there is no change in formal charge during the charge / discharge process.

  A secondary battery according to a fourth aspect of the present invention is the secondary battery according to the second aspect, wherein the organic redox compound is a compound represented by the following chemical formula 16.

(In the chemical formula 16, each of Z1 to Z2 is oxygen or sulfur, each of R8 to R11 is a chain or cyclic aliphatic group, and consists of oxygen, nitrogen, sulfur, silicon, phosphorus and boron. One or more selected from the group may be included, and may be the same as the elements of Z1 to Z2.)
According to the fourth aspect, the organic redox compound is the compound represented by the chemical formula 16, and the effect of the first aspect can be exhibited.

  A secondary battery according to a fifth aspect of the present invention is the secondary battery according to the second aspect, wherein the organic redox compound is a compound represented by the following chemical formula 17.

(In the chemical formula 17, each of Z3 to Z4 is nitrogen or phosphorus, each of R12 to R17 is a chain or cyclic aliphatic group, and is composed of oxygen, nitrogen, sulfur, silicon, phosphorus, and boron. One or more selected from the group may be included, and may be the same as the elements Z3 to Z4.)
According to the fifth aspect, the organic redox compound is the compound represented by the chemical formula 17, and the effect of the first aspect can be exhibited.

A secondary battery according to a sixth aspect of the present invention is the secondary battery according to any one of the first to fifth aspects, wherein the metal complex includes at least one metal element and has at least two organic redox compounds as a ligand.
According to claim 6, when the metal complex is made of a complex of a metal element and an organic redox compound, the effect of claim 1 can be exhibited.

  A secondary battery according to a seventh aspect of the present invention is the secondary battery according to any one of the first to sixth aspects, wherein the metal complex is represented by the following chemical formula (18).

(M1 in the chemical formula 18 is a transition metal element of Group 4 to 12, and at least two of L1 to L6 are the organic redox compounds, and each of the other L1 to L6 is neutral or anion. And is a chain or cyclic aliphatic group, and can form a chemical bond with neutral or anionic carbon, nitrogen, oxygen, silicon, phosphorus, sulfur, halogen elements and M1.)
According to claim 7, the metal complex is a compound represented by formula 18 and the effect of claim 1 can be exhibited.

  In the secondary battery according to an eighth aspect of the present invention, in any one of the first to sixth aspects, the metal complex is represented by the following chemical formula 19.

(Each of Z5 to Z8 in the formula 19 is selected from nitrogen, oxygen, sulfur and phosphorus, L7 to L8 are organic redox compounds according to claim 2, and each of R18 to R19 has a carbon number. 1 to 16 chain or cyclic aliphatic groups, which may contain one or more elements selected from the group consisting of oxygen, nitrogen, sulfur, silicon, phosphorus and boron.)
According to claim 8, the metal complex is a compound represented by the formula 19, and the effect of claim 1 can be exhibited.

  In the compound represented by the formula 19, Z5-8 is preferably oxygen or nitrogen, and carboxylate (examples of carboxylic acid as a precursor include formic acid, acetic acid, propionic acid, entangling acid, valeric acid, capron Acid, decanoic acid, succinic acid, acrylic acid, methacrylic acid, benzoic acid, phthalic acid, naphthalenecarboxylic acid, malic acid, etc., but not limited to them), amidinate (amidine precursor) Examples include, but are not limited to, formamidine, acetamidine, chloroacetamidine, difluoroacetamidine, pentafluoropropylamidine, benzamidine, 4-aminobenzamidine, 4-hydroxybenzamidine, 4-nitrobenzamidine and the like. ), Amidate (the precursor amidate) Examples of formamide, acetamide, benzamide, 4-n-butylbenzamide, 2-aminobenzamide, N-benzylformamide, nicotinamide, 5-bromonicotinamide, malonamide, acrylamide, 4′-aminoacetanilide, 1-acetamidoadamantane Etc., but is not limited thereto.) Is more preferable. M2 is not particularly limited, but is preferably manganese, iron, cobalt, nickel, copper, or zinc.

  A secondary battery according to a ninth aspect of the present invention is the secondary battery according to any one of the first to sixth aspects, wherein the metal complex is represented by the following chemical formula 20.

(Each of Z9 to Z12 in the formula 20 is selected from nitrogen, oxygen, sulfur and phosphorus, L9 to L10 are the organic redox compounds according to claim 2, and each of R20 to R25 has a carbon number. 1 to 16 chain or cyclic aliphatic groups, which may contain one or more elements selected from the group consisting of oxygen, nitrogen, sulfur, silicon, phosphorus and boron.)
According to the ninth aspect, the metal complex is a compound described in the chemical formula 20, and the effect of the first aspect can be exhibited.

  In the compound represented by the formula 20, each of Z9 to Z12 is preferably oxygen, and an acetylacetonate derivative (as an example of a diketone as a precursor, acetylacetone, 2,6-dimethyl-3,5-heptane) And dione, 3-methyl-2,4-pentanedione, dipivaloylmethane, hexafluoroacetylacetone and the like, but are not limited thereto. M3 is not particularly limited, but is preferably manganese, iron, cobalt, nickel, copper, or zinc.

  A secondary battery according to a tenth aspect of the present invention is the secondary battery according to any one of the first to sixth aspects, wherein the metal complex is represented by the following formula 21:

Wherein each of L11 to L12 in the chemical formula 21 is an organic redox compound according to claim 2, each of R26 to R37 is a linear or cyclic aliphatic group having 1 to 16 carbon atoms, and oxygen And one or more elements selected from the group consisting of nitrogen, sulfur, silicon, phosphorus and boron.
According to the tenth aspect, the metal complex is a compound represented by the chemical formula 21, and the effect of the first aspect can be exhibited.

  Examples of the porphyrin which is a precursor of the ligand in the compound represented by the formula 21 include porphyrin, tetraphenylporphine, phthalocyanine, tetrakis (4-carboxyphenyl) porphyrin, 5,10,15,20-tetrakis ( Pentafluorophenyl) -21H, 23H-porphine, 5,10,15,20-tetra (4-pyridyl) -21H, 23H-porphine and the like. M4 is not particularly limited, but is preferably manganese, iron, cobalt, nickel, copper, or zinc.

  A secondary battery according to an eleventh aspect of the present invention is the secondary battery according to any one of the first to sixth aspects, wherein the metal complex is represented by the following chemical formula 22.

(Each of M5 to M6 in the chemical formula 22 is a transition metal element of Group 4 to 12, at least two of L13 to L22 are the organic redox compounds, and each of the other L13 to L22 is Neutral or anionic, linear or cyclic aliphatic group that can form chemical bonds with neutral or anionic carbon, nitrogen, oxygen, silicon, phosphorus, sulfur, halogen elements and M1 it can.)
According to the eleventh aspect, the metal complex is a compound described in the chemical formula 22, and the effect of the first aspect can be exhibited.

  In the compound represented by the chemical formula 22, M5 and 6 are not particularly limited, but are preferably manganese, iron, cobalt, nickel, molybdenum, tungsten, ruthenium, or rhodium.

  A secondary battery according to a twelfth aspect of the present invention is the secondary battery according to any one of the first to sixth aspects, wherein the metal complex is represented by the following chemical formula 23.

(Each of M7 to M8 in the chemical formula 23 is a transition metal element of Group 4 to 12, and may not be bonded between M7 and M8. Each of Z13 to Z16 may be nitrogen, oxygen, sulfur, Each of L23 to L24 is selected from phosphorus, at least two of which are the above organic redox compounds, each of L25 to L28 is neutral or anionic, and is a chain or cyclic aliphatic group; Each of ˜R39 is a linear or cyclic aliphatic group having 1 to 16 carbon atoms, and includes one or more elements selected from the group consisting of oxygen, nitrogen, sulfur, silicon, phosphorus, and boron. it can.)
According to the twelfth aspect, the metal complex is a compound represented by Formula 23, and the effect of the first aspect can be exhibited.

  In the compound represented by the formula 23, each of Z13 to Z16 is preferably oxygen or nitrogen, and carboxylate (examples of the precursor carboxylic acid include formic acid, acetic acid, propionic acid, entangling acid, and valeric acid. , Caproic acid, decanoic acid, succinic acid, acrylic acid, methacrylic acid, benzoic acid, phthalic acid, naphthalenecarboxylic acid, malic acid, and the like.), Amidinate (a precursor) Examples of amidine include formamidine, acetamidine, chloroacetamidine, difluoroacetamidine, pentafluoropropylamidine, benzamidine, 4-aminobenzamidine, 4-hydroxybenzamidine, 4-nitrobenzamidine and the like. Not limited), amidate ( Examples of amides that are precursors include formamide, acetamide, benzamide, 4-n-butylbenzamide, 2-aminobenzamide, N-benzylformamide, nicotinamide, 5-bromonicotinamide, malonamide, acrylamide, 4′-aminoacetanilide , 1-acetamidoadamantane, and the like, but is not limited thereto. Moreover, although there is no restriction | limiting in particular, It is more preferable that L26-28 is a structure which has a bridge | crosslinking structure with M2-M3 similarly to Z5. Moreover, although M7-8 is not specifically limited, It is preferable that they are manganese, iron, cobalt, nickel, molybdenum, tungsten, ruthenium, and rhodium.

  A secondary battery according to a thirteenth aspect of the present invention is the secondary battery according to any one of the first to sixth aspects, wherein the metal complex is represented by the following chemical formula 24.

(Each of M9 to M11 in the chemical formula 24 is a transition metal element of group 4 to 12, each of Z17 to Z23 is selected from nitrogen, oxygen, sulfur and phosphorus, and each of L29 to L31 is It is an organic redox compound, and each of R40 to R42 is a chain or cyclic aliphatic group having 1 to 16 carbon atoms, and one kind selected from the group consisting of oxygen, nitrogen, sulfur, silicon, phosphorus and boron The above elements can be included.)
According to the thirteenth aspect, the metal complex is a compound represented by the chemical formula 24, and the effect of the first aspect can be exhibited.

  In the compound represented by Formula 24, although there is no particular limitation, each of Z17 to Z23 is preferably oxygen or nitrogen, and carboxylate (for example, formic acid, acetic acid, propionic acid as examples of the carboxylic acid as a precursor) , Enthalic acid, valeric acid, caproic acid, decanoic acid, succinic acid, acrylic acid, methacrylic acid, benzoic acid, phthalic acid, naphthalenecarboxylic acid, malic acid and the like, but are not limited thereto. Amidinate (examples of the precursor amidine include formamidine, acetamidine, chloroacetamidine, difluoroacetamidine, pentafluoropropylamidine, benzamidine, 4-aminobenzamidine, 4-hydroxybenzamidine, 4-nitrobenzamidine, etc. But not limited to ), Amidate (as examples of amides as precursors, formamide, acetamide, benzamide, 4-n-butylbenzamide, 2-aminobenzamide, N-benzylformamide, nicotinamide, 5-bromonicotinamide, malonamide, acrylamide, 4 '-Aminoacetanilide, 1-acetamidoadamantane and the like can be mentioned but are not limited thereto. Moreover, although M9-11 is not specifically limited, It is preferable that they are manganese, iron, cobalt, nickel, molybdenum, tungsten, ruthenium, and rhodium.

A secondary battery according to a fourteenth aspect of the present invention is the secondary battery according to any one of the first to thirteenth aspects, wherein the copolymer composed of the organic redox compound and the metal complex has 5 to 100,000 repeating units.
According to the fourteenth aspect, the effect of the first aspect can be exhibited when the number of repeating units of the copolymer composed of the organic redox compound and the metal complex is within a predetermined range.

  In the secondary battery of the present invention, an organic redox compound contained in at least one of a positive electrode and a negative electrode functions as an active material, and the organic redox compound forms a copolymer with a metal complex, whereby an electrolytic solution of the organic redox compound Elution can be suppressed. Thereby, the secondary battery of this invention can suppress the fall of the cycling characteristics by the elution of the organic redox compound which is an active material, and can maintain a high battery characteristic.

(Copolymer)
The secondary battery of the present invention comprises an organic redox compound described in Formulas 1 to 5 (Formulas 13 to 17) and a metal complex copolymer described in Formulas 6 to 12 (Formulas 18 to 24). , As an active material.

  Examples of the method for producing a copolymer include a method obtained as a precipitate by mixing a solution of an organic redox compound and a metal complex. In addition, the ligand and the organic redox compound can be exchanged by heating or using an indicator.

(Secondary battery)
The secondary battery of the present invention has a copolymer of an organic redox compound and a metal complex contained in at least one of a positive electrode and a negative electrode as an active material. The secondary battery of the present invention can have the same configuration as a conventionally known secondary battery except that at least one of the positive electrode and the negative electrode has a copolymer of an organic redox compound and a metal complex.

  That is, the secondary battery of the present invention may be a battery having a positive electrode, a negative electrode, and an electrolytic solution. The secondary battery of the present invention is preferably a non-aqueous electrolyte battery, and more preferably a lithium ion secondary battery. The positive electrode and the negative electrode may be formed by forming on the surface of the current collector an electrode mixture layer in which an additive selected from active materials, binders, conductive materials, and other materials as necessary is mixed. preferable.

(Electrode active material)
In the secondary battery of the present invention, the active material for the positive electrode or the negative electrode is not limited to the above-mentioned copolymer, but can be used by mixing with a compound used as an active material in a conventional secondary battery.

An example of such a compound is a lithium-containing transition metal oxide that is a positive electrode active material of a lithium ion secondary battery. The lithium-containing transition metal oxide is a material that can insert and remove Li ions (Li ⁺ ), and includes a lithium-metal composite oxide having a layered structure or a spinel structure. Specific examples include metal oxide materials such as Li _1-Z NiO ₂ , Li _1-Z MnO ₂ , Li _1-Z Mn ₂ O ₄ , and Li _1-Z CoO ₂ . Furthermore, examples of Li _1-Z βPO ₄ include LiFePO _4, and examples thereof include compounds containing one or more of them. Z represents a number from 0 to 1. In addition, each metal oxide-based material may be Li, Mg, Al, or a material in which a transition metal such as Co, Ti, Nb, or Cr is added or substituted. Furthermore, these lithium-metal composite oxides may be used alone or in combination.

(Other configurations)
The binder is desirably formed of a polymer material, and is desirably a material that is chemically and physically stable in the atmosphere in the secondary battery. Examples of the binder include polyvinylidene fluoride, polytetrafluoroethylene (PTFE), and carboxymethyl cellulose (CMC).

  Examples of the conductive material include ketjen black, acetylene black, carbon black, graphite, carbon nanotube, and amorphous carbon. In addition, conductive polymer polyaniline, polypyrrole, polythiophene, polyacetylene, polyacene, and the like can be given.

  As a method of forming an electrode mixture layer on the surface of the current collector, an electrode mixture having an active material, a binder, and a conductive material is dispersed or dissolved in an appropriate dispersion medium, and then the surface of the current collector The method of applying and drying can be mentioned.

When the secondary battery of the present invention is a lithium ion secondary battery and the positive electrode has a copolymer, a compound that absorbs lithium ions during charging and releases them during discharging can be used as the active material of the negative electrode. . The negative electrode active material is not particularly limited in its material configuration, and known materials and configurations can be used. Examples thereof include carbon materials such as lithium metal, graphite or amorphous carbon, alloy materials containing silicon and tin, and oxide materials such as Li ₄ Ti ₅ O ₁₂ and Nb ₂ O ₅ .

  The electrolytic solution is not particularly limited, and an electrolytic solution in which a supporting salt is dissolved in a solvent such as an organic solvent, an ionic liquid that is liquid itself, or a supporting salt that is further dissolved in the ionic liquid. I can give you.

  As an organic solvent, the organic solvent used for the electrolyte solution of a normal lithium ion secondary battery can be mention | raise | lifted. Examples thereof include carbonates, halogenated hydrocarbons, ethers, ketones, nitriles, lactones, oxolane compounds and the like. In particular, it is preferable to use propylene carbonate, ethylene carbonate, 1,2-dimethoxyethane, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, or a mixed solvent thereof. Among these organic solvents, in particular, one or more non-aqueous solvents selected from the group consisting of carbonates and ethers are excellent in the solubility, dielectric constant and viscosity of the supporting salt, and the charge / discharge efficiency of the battery is also high. Therefore, it is preferable.

An ionic liquid will not be specifically limited if it is an ionic liquid normally used for the electrolyte solution of a lithium secondary battery. For example, as the cation component of the ionic liquid, or N- methyl -N- propyl piperidinium, and dimethyl ethyl methoxy ammonium cations like, and an anionic _{component, BF 4 -, N (SO} 2 CF 3) ₂ etc. can be mentioned.

In the secondary battery of the present invention, the supporting salt used in the electrolytic solution is not particularly limited. For example, LiPF ₆ , LiBF ₄ , LiAsF ₆ , LiCF ₃ SO ₃ , LiN (CF ₃ SO ₂ ) _{2 , LiC (CF 3 SO 2)} 3, LiSbF 6, LiSCN, LiClO 4, LiAlCl 4, NaClO 4, NaBF 4, NaI, may be mentioned salt compounds such as derivatives thereof. Among these, LiPF ₆ , LiBF ₄ , LiClO ₄ , LiAsF ₆ , LiCF ₃ SO ₃ , LiN (CF ₃ SO ₂ ) ₂ , LiC (CF ₃ SO ₂ ) ₃ , LiN (FSO ₂ ) ₂ , LiN (CF ₃ One or more selected from the group consisting of a derivative of SO ₂ ) (C ₄ F ₉ SO ₂ ), a derivative of LiCF ₃ SO _3, a derivative of LiN (CF ₃ SO ₂ ) _{2 and} a derivative of LiC (CF ₃ SO ₂ ) ₃ It is preferable to use a salt from the viewpoint of electrical characteristics.

  In the secondary battery of the present invention, it is preferable to interpose a separator, which is a member that achieves both electrical insulation and ion conduction, between the positive electrode and the negative electrode. When the supporting electrolyte is liquid, the separator also serves to hold the liquid supporting electrolyte. Examples of the separator include a porous synthetic resin film, particularly a porous film of polyolefin polymer (polyethylene, polypropylene). Furthermore, it is preferable that the separator has a larger size than the positive electrode and the negative electrode for the purpose of ensuring the insulation between the positive electrode and the negative electrode.

  The secondary battery according to the present invention includes elements other than the above elements as required. The shape of the secondary battery of the present invention is not particularly limited, and batteries of various shapes such as a coin shape, a cylindrical shape, and a square shape can be used.

  Hereinafter, the present invention will be described using examples.

  As an example of the present invention, a coin-type lithium ion secondary battery was manufactured.

Example 1
(Synthesis of copolymer)
First, 30 mg of a compound represented by the formula 25 was measured as an organic redox compound in a Schlenk flask and dissolved in 50 ml of alcohol (ethanol, isopropyl alcohol, etc.). This solution is designated as solution (I).

  Next, 37 mg of a compound represented by the formula 26 was measured as a metal complex in a Schlenk flask and dissolved in 50 ml of alcohol (ethanol, isopropyl alcohol, etc.). Let this solution be solution (II).

  Solutions (I) and (II) were uniformly mixed in a Schlenk flask and allowed to stand at room temperature for several days. The precipitate was collected by filtration and washed with ethanol.

  Thus, a copolymer (A) of an organic redox compound represented by the formula 25 and a metal complex represented by the formula 26 was obtained in a yield of 45%.

(Creation of positive electrode)
20 mg of the obtained copolymer (A) and 20 mg of acetylene black as a conductive material were uniformly mixed, 1 ml of N-methyl-2-pyrrolidone was added as a solvent, and 10 mg of polyvinylidene fluoride was added as a binder, Mixing until uniform, a black slurry was obtained. This was cast on an aluminum foil current collector and vacuum-dried at 60 ° C. for 1 hour. This was punched into a 13 mm disk shape to form a positive electrode.

(Preparation of electrolyte)
LiPF ₆ was added to an organic solvent in which ethylene carbonate (EC) and diethyl carbonate (DEC) were mixed at a mass ratio of 3: 7 to a concentration of 1.0 mol / L to obtain an electrolytic solution.

(Production of coin-type battery)
A coin-type battery was manufactured using the manufactured positive electrode 1 of this example. A coin-type battery 1 of this example is shown in FIG. The coin-type battery of this example includes a positive electrode 2, a negative electrode 3, an electrolytic solution 4, and a separator 7. The negative electrode 3 was made of metallic lithium, the electrolytic solution 4 was the prepared electrolytic solution, and the separator 7 was a 25 μm thick polyethylene porous membrane. The positive electrode 2 has a positive electrode current collector 2a, and the negative electrode 3 has a negative electrode current collector 3a.

  These power generation elements were housed in a stainless steel case (consisting of a positive electrode case 50 and a negative electrode case 51). The positive electrode case 50 and the negative electrode case 51 serve as a positive electrode terminal and a negative electrode terminal. A gasket 6 made of polypropylene is interposed between the positive electrode case 50 and the negative electrode case 51 to ensure sealing and insulation between the positive electrode case 50 and the negative electrode case 51.

(Comparative Example 1)
This comparative example is a coin-type battery manufactured in the same manner as in Example 1 except that tetrathiafulvalene (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of the copolymer (A).

(Comparative Example 2)
This comparative example was carried out in the same manner as in Example 1 except that bis (ethylenedithio) tetrathiafulvalene (manufactured by Tokyo Chemical Industry Co., Ltd.), which is a tetrathiafulvalene derivative, was used instead of the copolymer (A). It is a coin-type battery manufactured in this way.

(Example 2)
The coin-type battery was manufactured in the same manner as in Example 1 except that the compound represented by the formula 27 was used as the organic redox compound.

(Example 3)
A coin-type battery manufactured in the same manner as in Example 1 except that the compound represented by the formula 28 was used as the metal complex.

Example 4
A coin-type battery produced in the same manner as in Example 2 except that the compound represented by the formula 29 was used as the metal complex.

(Example 5)
A coin-type battery manufactured in the same manner as in Example 2 except that iron acetate was used as the metal complex.

(Example 6)
A coin-type battery produced in the same manner as in Example 2 except that the compound represented by the formula 30 was used as the metal complex.

(Example 7)
The coin-type battery was manufactured in the same manner as in Example 2 except that the compound represented by the formula 31 was used as the metal complex.

(Example 8)
The coin-type battery was manufactured in the same manner as in Example 2 except that the compound represented by the formula 32 was used as the metal complex.

(Evaluation)
As an evaluation of the batteries manufactured in Examples and Comparative Examples, cycle characteristics were examined.

(Cycle characteristic test method)
First, constant current charging at a charging current 0.10mA / cm ² to 0.01 V, was constant current discharge to 1.5V at a discharge current 0.10mA / cm ^2. The discharge capacity at this time was defined as the initial discharge capacity.

After initial charge and discharge, a constant current charging at a charging current 0.10mA / cm ² to 0.01 V, was repeated cycles of constant current discharge to 1.5V at a discharge current 0.10mA / cm ^2. The discharge capacities at the 10th and 20th charge / discharge cycles were measured and are shown in Table 1 as the discharge capacity ratio. In Table 1, the initial discharge capacity was set to 100, and the discharge capacity ratio was determined from the following formula using the discharge capacity at the 10th and 20th cycles and the initial discharge capacity. In addition, the measurement of charging / discharging and discharge capacity was performed in 25 degreeC atmosphere.

  Discharge capacity ratio = [(discharge capacity in a predetermined cycle) / (initial discharge capacity)] × 100

  As shown in Table 1, the coin-type batteries of Examples 1 to 8 have a higher discharge capacity ratio than the coin-type batteries of Comparative Examples 1 and 2 in both the 10th cycle and the 20th cycle. I can confirm. In other words, it was confirmed that a battery having better cycle characteristics than the coin-type battery of the comparative example could be obtained by being included in the electrode (positive electrode) in a state where the organic redox compound and the metal complex formed a copolymer. .

It is a longitudinal cross-sectional view which shows roughly the structure of the coin-type battery manufactured in the Example.

Explanation of symbols

1: coin-type battery 2: positive electrode 2a: positive electrode current collector 3: negative electrode 3a: negative electrode current collector 4: electrolyte 50: positive electrode case 51: negative electrode case 6: gasket 7: separator

Claims (14)

In a secondary battery having a positive electrode and a negative electrode,
At least one of the positive electrode and the negative electrode is
A secondary battery comprising a copolymer of an organic redox compound having a substituent capable of multidentate coordination and a metal complex to which metal atoms are bonded. The secondary battery according to claim 1, wherein the organic redox compound is tetrathiafulvalene represented by the following chemical formula 1 or a derivative thereof.

(Here, R1 to R4 are chain or cyclic aliphatic groups, and at least two of R1 to R4 are represented by a nitrile group capable of coordinating with a metal or the following chemical formula 2 or chemical formula 3. Note that each of R1 to R4 may be the same group or a different group.)

(X and Y in Chemical Formula 2 and Chemical Formula 3 are elements selected from Groups 15 and 16 containing oxygen, nitrogen, phosphorus, and sulfur, which may be neutral or negatively charged. R5 to R7 may be a chain or cyclic aliphatic group or hydrogen, and may contain one or more elements selected from the group consisting of oxygen, nitrogen, sulfur, silicon, phosphorus, and boron. X, Y, and R5 to R7 may be the same group (element) or different groups (elements).   3. The secondary battery according to claim 2, wherein the organic redox compound is an element in which X and Y in the chemical formula 2 form a chemical bond with the metal complex and have no change in formal charge during a charge / discharge process. . The secondary battery according to claim 2, wherein the organic redox compound is a compound represented by the following chemical formula 4.

(Z1 to Z2 in the formula 4 are oxygen or sulfur. R8 to R11 are chain or cyclic aliphatic groups selected from the group consisting of oxygen, nitrogen, sulfur, silicon, phosphorus and boron. One or more elements may be included, and this element may be the same as the elements of Z1 to Z2, where Z1 to Z2 and R8 to R11 are each the same group (element). May be a different group (element) or any of them.) The secondary battery according to claim 2, wherein the organic redox compound is a compound represented by Formula 5 below.

(Each of Z3 to Z4 in the chemical formula 5 is nitrogen or phosphorus. R12 to R17 are chain or cyclic aliphatic groups from the group consisting of oxygen, nitrogen, sulfur, silicon, phosphorus and boron. One or more selected elements may be included, and this element may be the same as the elements of Z3 to Z4, where Z3 to Z4 and R12 to R17 are each the same group (element). Or a different group (element).   The secondary battery according to claim 1, wherein the metal complex includes at least one metal element and has at least two organic redox compounds as a ligand. The secondary battery according to claim 1, wherein the metal complex is represented by the following chemical formula 6.

(M1 in the chemical formula 6 is a transition metal element of Group 4 to 12. Among L1 to L6, at least two are the organic redox compounds, and the other L1 to L6 are neutral or anionic. Yes, it is a chain or cyclic aliphatic group, and can form a chemical bond with neutral or anionic carbon, nitrogen, oxygen, silicon, phosphorus, sulfur, halogen element and M1. L6 may be either the same group (compound) or different groups (compounds). The secondary battery according to claim 1, wherein the metal complex is represented by the following chemical formula 7.

(Z5 to Z8 in the formula 7 are selected from nitrogen, oxygen, sulfur and phosphorus. L7 to L8 are the organic redox compounds. R18 to R19 are linear or cyclic having 1 to 16 carbon atoms. And can contain one or more elements selected from the group consisting of oxygen, nitrogen, sulfur, silicon, phosphorus and boron, wherein Z5 to Z8, L7 to L8 and R18 to R19 are Each may be the same group (element, compound) or different group (element, compound). The secondary battery according to claim 1, wherein the metal complex is represented by the following chemical formula 8.

(Z9 to Z12 in the formula 8 are selected from nitrogen, oxygen, sulfur and phosphorus. L9 to L10 are the organic redox compounds. R20 to R25 are linear or cyclic having 1 to 16 carbon atoms. And can contain one or more elements selected from the group consisting of oxygen, nitrogen, sulfur, silicon, phosphorus and boron, wherein Z9 to Z12, L9 to L10 and R20 to R25 are Each may be the same group (element, compound) or different group (element, compound). The secondary battery according to claim 1, wherein the metal complex is represented by the following chemical formula 9.

(L11 to L12 in the chemical formula 9 are the organic redox compounds. R26 to R37 are chain or cyclic aliphatic groups having 1 to 16 carbon atoms, and include oxygen, nitrogen, sulfur, silicon, and phosphorus. And L11 to L12 and R26 to R37 may be different groups (compounds) even if they are the same group (compound). Or any.) The secondary battery according to claim 1, wherein the metal complex is represented by the following chemical formula 10.

(M5 to M6 in the chemical formula 10 are group 4 to 12 transition metal elements. Among L13 to L22, at least two are the organic redox compounds, and the other L13 to L22 are neutral or anion. It is a chain-like or cyclic aliphatic group and can form a chemical bond with neutral or anionic carbon, nitrogen, oxygen, silicon, phosphorus, sulfur, halogen elements and M1. , M5 to M6 and L13 to L22 may be either the same group (element, compound) or different groups (element, compound). The secondary battery according to claim 1, wherein the metal complex is represented by the following chemical formula 11.

(M7 to M8 in the chemical formula 11 are group 4 to 12 transition metal elements. Here, M7 and M8 may not be bonded. Z13 to Z16 are nitrogen, oxygen, and sulfur. L23 to L24 are the organic redox compounds, L25 to L28 are neutral or anionic, and are a chain or cyclic aliphatic group, and R38 to R39 each have a carbon number. 1 to 16 chain or cyclic aliphatic groups, which may contain one or more elements selected from the group consisting of oxygen, nitrogen, sulfur, silicon, phosphorus, and boron. ˜Z16, L23 to L28, and R38 to R39 may be the same group (element, compound) or different groups (element, compound). The secondary battery according to claim 1, wherein the metal complex is represented by the following chemical formula 12.

(M9 to M11 in the chemical formula 12 are Group 4 to 12 transition metal elements. Z17 to Z23 are selected from nitrogen, oxygen, sulfur, and phosphorus. L29 to L31 are the organic redox compounds. R40 to R42 are linear or cyclic aliphatic groups having 1 to 16 carbon atoms, and can contain one or more elements selected from the group consisting of oxygen, nitrogen, sulfur, silicon, phosphorus and boron. M9 to M11, Z17 to Z23, L29 to L31, and R40 to R42 may be the same group (element, compound) or different groups (element, compound). .)   The secondary battery according to any one of claims 1 to 13, wherein the copolymer composed of the organic redox compound and the metal complex has 5 to 100,000 repeating units.

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