JP2013227578A - Novel polymer and nonaqueous electrolyte secondary battery using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrode additive for secondary battery which is never deteriorated, in a nonaqueous electrolyte secondary battery using an easy-to-elute metal such as manganese as an active material, even during high-temperature storage and even in charge and discharge cycles, and a nonaqueous electrolyte secondary battery containing the electrode additive for secondary battery.SOLUTION: A polymer including a structural unit expressed by general formula (A) or (C) and a structural unit expressed by general formula (B) is used as an electrode additive. (In the formulae, R, R, Rand Reach independently represent any of hydrogen atom, methyl or methoxy, Rrepresents any of 1-6C alkyl, 1-6C alkoxy, hydroxy or hydrogen atom, Rrepresents 2-6C alkylene, and Mrepresents any of hydrogen, lithium, sodium or potassium).

Description

  The present invention relates to a novel polymer suitable as an electrode additive and a non-aqueous electrolyte secondary battery using the polymer.

  With the spread of portable electronic devices such as portable personal computers and handy video cameras in recent years, non-aqueous electrolyte secondary batteries having high voltage and high energy density have been widely used as power sources. Also, from the viewpoint of environmental problems, battery cars and hybrid cars using electric power as a part of power have been put into practical use.

A composite oxide containing lithium and a transition metal element is often used as a positive electrode active material for a non-aqueous electrolyte secondary battery. Due to the rapid rise in the price of rare metals such as cobalt in recent years, a composite containing inexpensive manganese. Oxides are increasingly being used.
A complex oxide containing manganese exhibits excellent economic efficiency and high safety during overcharge, but has a problem in that manganese does not necessarily have sufficient resistance to dissolution in a non-aqueous electrolyte. That is, manganese ions are eluted from the positive electrode during high-temperature storage or charge / discharge, and the manganese precipitates on the end face of the graphite of the negative electrode, thereby inhibiting lithium ion insertion and desorption from the negative electrode graphite. It has been revealed.
As a method for suppressing elution of manganese from a complex oxide containing manganese, a method of adding a different element to the complex oxide has been proposed. Patent Document 1 proposes a method of adding boron to the composite oxide, and Patent Document 2 proposes a method of adding chromium, cobalt, nickel, and iron to the composite oxide. In No. 3, a method of adding aluminum or magnesium to the composite oxide has been proposed, and as a result, elution of manganese was suppressed to some extent, but the effect was not yet sufficient.
In order to prevent the eluted manganese from precipitating on the end face of the graphite, a method of adding an additive to the non-aqueous electrolyte is known. Patent Document 4 proposes an electrolyte containing a cyclic sulfonate ester. Patent Document 5 proposes a nonaqueous electrolytic solution containing a disulfonic acid ester. These additives form a thick film that prevents the entry of manganese on the surface of the negative electrode. Although this film has the effect of preventing the entry of manganese by the film, the internal resistance of the battery increases and the output characteristics of the battery are reduced. It was a sacrifice.

JP 05-283077 A JP-A-11-71115 JP 2000-327332 A JP 2005-149750 A Japanese Patent No. 2005-203342

  The object of the present invention is to provide a high capacity and high output even in a non-aqueous electrolyte secondary battery using a metal such as manganese, which is easily eluted, as an electrode active material, during high temperature storage and after repeated cycles of charge and discharge. An object of the present invention is to provide a high-performance secondary battery electrode additive that can be maintained and a non-aqueous electrolyte secondary battery containing the secondary battery electrode additive.

  As a result of intensive studies, the present inventors have found that a polymer having a specific chemical structure site bonded can be an electrode additive for a secondary battery that meets the object of the present invention.

（式中、Ｒ₁、Ｒ₂、Ｒ₃及びＲ₄は、それぞれ独立に、水素原子、メチル基又はメトキシ基の何れかを示し、Ｒ₅は炭素数１〜６のアルキル基、炭素数１〜６のアルコキシ基、水酸基、水素原子の何れかを示し、Ｍ₁は水素、リチウム、ナトリウム又はカリウムの何れかを示す。）
で表される構成単位と、
下記一般式（Ｂ）

（式中、Ｒ₁、Ｒ₂、Ｒ₃、Ｒ₄及びＭ₁は、上記一般式（Ａ）と同義である。）
で表わされる構成単位とを含むことを特徴とする重合体（以下、第一の重合体とも言う）を提供するものである。 The present invention has been made based on the above findings,
The following general formula (A)

(Wherein R ₁ , R ₂ , R ₃ and R ₄ each independently represents any one of a hydrogen atom, a methyl group or a methoxy group, R ₅ is an alkyl group having 1 to 6 carbon atoms and 1 carbon atom) -6 represents an alkoxy group, a hydroxyl group, or a hydrogen atom, and M ₁ represents hydrogen, lithium, sodium, or potassium.)
A structural unit represented by
The following general formula (B)

(In the formula, R ₁ , R ₂ , R ₃ , R ₄ and M ₁ have the same meaning as in the general formula (A).)
And a structural unit represented by the formula (hereinafter also referred to as a first polymer).

（式中、Ｒ₁、Ｒ₂、Ｒ₃、Ｒ₄及びＭ₁は、上記一般式（Ａ）と同義であり、Ｒ₆は炭素数２〜６のアルキレン基を示す。）
で表される構成単位と、
下記一般式（Ｂ）

（式中、Ｒ₁、Ｒ₂、Ｒ₃、Ｒ₄及びＭ₁は、上記一般式（Ａ）と同義である。）
で表わされる構成単位とを含むことを特徴とする重合体（以下、第二の重合体とも言う）を提供するものである。 Further, the present invention provides the following general formula (C)

(In the formula, R ₁ , R ₂ , R ₃ , R ₄ and M ₁ have the same meaning as in the general formula (A), and R ₆ represents an alkylene group having 2 to ₆ carbon atoms.)
A structural unit represented by
The following general formula (B)

(In the formula, R ₁ , R ₂ , R ₃ , R ₄ and M ₁ have the same meaning as in the general formula (A).)
And a structural unit represented by the formula (hereinafter also referred to as a second polymer).

  Moreover, this invention provides the nonaqueous electrolyte secondary battery which contains the said polymer in an electrode.

  The novel polymer of the present invention is a polymer in which specific chemical structural sites are bonded. When an electrode material is produced using this polymer, the polymer is sufficiently dispersed with the electrode active material in a slurry made of water or an organic solvent for coating the electrode material, and the electrode layer is also applied after coating and drying. Can maintain a highly dispersed state. In particular, in a non-aqueous electrolyte secondary battery using a compound containing manganese in the positive electrode and graphite in the negative electrode, the non-aqueous electrolyte secondary battery containing the polymer of the present invention as an electrode additive in the electrode is manganese. Even if it elutes from the positive electrode and penetrates into the negative electrode, the eluted manganese is trapped by the specific chemical structure part of the polymer contained in the electrode as an electrode additive. There is almost no manganese reaching the end face of graphite. Due to the effect, deterioration of the cycle capacity of the non-aqueous electrolyte secondary battery due to eluted manganese is suppressed.

FIG. 1 is a longitudinal sectional view schematically showing an example of the structure of a coin-type battery of the nonaqueous electrolyte secondary battery of the present invention. FIG. 2 is a schematic diagram showing a basic configuration of a cylindrical battery of the nonaqueous electrolyte secondary battery of the present invention. FIG. 3 is a perspective view showing the internal structure of the cylindrical battery of the nonaqueous electrolyte secondary battery of the present invention as a cross section.

  Below, the novel polymer which the specific chemical structure site | part of this invention couple | bonded and the nonaqueous electrolyte secondary battery using this polymer are explained in full detail.

で表される構成単位と、
下記一般式（Ｂ）

で表わされる構成単位とを含む。 First, the first polymer will be described.
The first polymer has the following general formula (A)

A structural unit represented by
The following general formula (B)

And a structural unit represented by

In the above general formula (A) or (B), R ₁ , R ₂ , R ₃ and R ₄ each independently represent any of hydrogen, methyl group and methoxy group, and R ₅ has 1 to 6 carbon atoms. Or an alkyl group having 1 to 6 carbon atoms, a hydroxyl group, or a hydrogen atom, and M ₁ represents any _one of hydrogen, lithium, sodium, and potassium. Examples of the alkyl group having 1 to 6 carbon atoms represented by R ₅ include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, t-butyl, pentyl, isopentyl, sec-pentyl, t-pentyl, hexyl, Examples thereof include linear or branched alkyl groups such as sec-hexyl, and examples of the alkoxy group having 1 to 6 carbon atoms represented by R ₅ include methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, sec-butoxy, t Examples include linear or branched alkoxy groups such as -butoxy, pentyloxy, isopentyloxy, sec-pentyloxy, t-pentyloxy, hexyloxy, sec-hexyloxy and the like.

As a polymer containing the structural unit represented by the general formula (A) and the structural unit represented by the general formula (B),
A polymer represented by the following general formula (1) can be exemplified.

In the general formula (1), R ₁ , R ₂ , R ₃ , R ₄ , R ₅ and M ₁ have the same meaning as the general formula (A), and m and n are m + n is 5 or more, And m / n shows the number which is 1/99 or more and 99/1 or less. Here, m + n is preferably 5 or more and 100000 or less, and more preferably 100 or more and 50000 or less. Further, m / n is preferably from 1/9 to 99/1, and more preferably from 3/7 to 98/2.

Examples of the polymer to which the specific chemical structure represented by the general formula (1) is bonded include Compound No. 1-No. 5 and the like, but are not limited to these compounds.

で表わされる構成単位と、
下記一般式（Ｂ）

で表わされる構成単位とを含む。 Next, the second polymer will be described.
The second polymer has the following general formula (C)

A structural unit represented by
The following general formula (B)

And a structural unit represented by

In the above general formula (B) or (C), R ₁ , R ₂ , R ₃ , R ₄ and M ₁ are as defined in the above general formula (A), and R ₆ is an alkylene group having 2 to ₆ carbon atoms. Indicates. Examples of the alkylene group having 1 to 6 carbon atoms represented by R ₆ include methylene, ethylene, propylene, methylethylene, butylene, 1-methylpropylene, 2-methylpropylene, 1,2-dimethylpropylene, and 1,3-dimethylpropylene. , Linear or branched alkylene groups such as 1-methylbutylene, 2-methylbutylene, 3-methylbutylene, 4-methylbutylene, 2,4-dimethylbutylene, 1,3-dimethylbutylene, pentylene, hexylene, etc. It is done.

As a polymer containing the structural unit represented by the general formula (C) and the structural unit represented by the general formula (B),
A polymer represented by the following general formula (2) can be exemplified.

In the general formula (2), R ₁ , R ₂ , R ₃ , R ₄ and M ₁ have the same meaning as the general formula (A), and R ₆ has the same meaning as the general formula (C). m and n are synonymous with the said General formula (1).

Examples of the polymer to which the specific chemical structure represented by the general formula (2) is bonded include Compound No. 6-No. 9 and the like, but are not limited to these compounds.

  In the 1st polymer and the 2nd polymer, in the range (preferably 0.1-20 mass%) which does not impair the effect of the present invention, in the above-mentioned general formula (A), (B) and (C) A structure other than the structural unit represented may be included. Examples of such a structure include a carboxylic acid alkyl ester, a carboxylic acid alkylamide, and a carboxylic acid anhydride.

The first polymer and the second polymer are prepared by reacting a copolymer of maleic anhydride and olefin synthesized by a conventionally known method with an amine or hydrazide having a specific chemical structure. It can be synthesized by binding a specific chemical structure site to the union and then neutralizing with an alkaline substance (such as lithium salt, calcium salt and potassium salt) if necessary. The reaction of a maleic anhydride / olefin copolymer with an amine or hydrazide having a specific chemical structure can also be carried out by a conventionally known method.
When a structure other than the structural units represented by the general formulas (A), (B) and (C) is introduced, a copolymer of maleic anhydride and olefin, salicylic acid hydrazide, hydroxylation in water or an organic solvent. An aminosulfonic acid such as an alkali, alkali carbonate, or taurine may be reacted at room temperature or under heating conditions, respectively.
The maleic anhydride and olefin copolymer includes maleic anhydride and ethylene copolymer, maleic anhydride and propylene copolymer, maleic anhydride and isobutylene copolymer, maleic anhydride and methyl vinyl ether copolymer. A polymer etc. are mentioned. The weight average molecular weight of the copolymer of maleic anhydride and olefin is 1000 to 3 million, preferably 10,000 to 3 million. A weight average molecular weight of less than 1000 is not preferred because it is easily dissolved in the electrolytic solution. On the other hand, when the weight average molecular weight exceeds 3 million, the viscosity of the solution becomes too large and the workability of coating the electrode material tends to be inferior.

The novel polymer of the present invention can be used as an electrode additive for an electrode (positive electrode or negative electrode) of a non-aqueous electrolyte secondary battery, a metal deactivator for an additive for plastics, an ion exchange resin, etc. Can be used.
Next, the nonaqueous electrolyte secondary battery of the present invention will be described.

  The nonaqueous electrolyte secondary battery of the present invention is configured in the same manner as a conventionally known nonaqueous electrolyte secondary battery except that the polymer of the present invention is contained in the electrode (positive electrode or negative electrode) as an electrode additive. Is done.

  In the nonaqueous electrolyte secondary battery of the present invention, the content of the polymer of the present invention is preferably 0.01 to 20% by mass, more preferably 0.03 to 10% by mass, based on the electrode active material. 0.05-5 mass% is the most preferable. If it is less than 0.01% by mass, the effect is hardly recognized, and even if it is contained in excess of 20% by mass, the effect will not be manifested any more, so it is not only useless but also limits the capacity of the battery. Therefore, it is not preferable. The polymers to which specific chemical structural sites are bonded can be used alone or in combination of two or more.

  The electrode material constituting the non-aqueous electrolyte secondary battery of the present invention includes a positive electrode and a negative electrode. As the positive electrode, a positive electrode active material, a binder, and a conductive material are slurried with an organic solvent or water. It is applied to a current collector and dried to form a sheet. When the polymer having a specific chemical structure site bonded thereto is used for the positive electrode in the present invention, the polymer having the specific chemical structure site bonded, the positive electrode active material, the binder, and the conductive material are slurried with an organic solvent or water. The resulting product is applied to a current collector and dried to form a sheet.

If the lithium ion battery is taken as an example of the positive electrode active material, a known positive electrode active material capable of occluding and releasing lithium as an electrode reactant can be used. Specific examples of the positive electrode active material capable of occluding and releasing lithium include metal oxides such as TiO ₂ , V ₂ O ₅ and MnO ₂ , metals such as TiS ₂ , TiS ₃ , MoS ₃ and FeS _2. Examples thereof include metal compounds such as sulfides, metal halides such as FeF ₃ , metal intercalation compounds, and metal phosphate compounds. These positive electrode active materials may be materials in which transition metals such as Li, Mg, Al, Co, Ti, Nb, and Cr are added or substituted. Among these, composite oxides containing lithium and a transition metal element are preferable, and those containing at least one of Ni, Co, Mn, Ti, and Fe are particularly preferable as transition metal elements, and those containing Mn. When used, the effect of the present invention is noticeable.

Such a composite oxide containing lithium and a transition metal element is typically represented by the following general formula (3):
Li _x M ¹ O ₂ (3)
(M ¹ in Formula (3) represents one or more transition metal elements, and the value of x varies depending on the charge / discharge state of the battery, but is usually 0.05 ≦ x ≦ 1.10.), The compound of formula (3) generally has a layered structure.

Specific examples of the composite oxide containing lithium and a transition metal element include, for example, lithium cobalt composite oxide (Li _x CoO ₂ ), lithium nickel composite oxide (Li _x NiO ₂ ), or lithium nickel cobalt composite oxide. (Li _x Ni _1-z Co _z O ₂ (z <1)), lithium nickel cobalt manganese composite oxide (Li _x Ni _1-vw Co _v Mn _w O ₂ (v + w <1)), etc. A composite oxide containing a different additive element based on a lithium nickelate structure, a lithium manganese composite oxide (LiMn ₂ O ₄ ) having a layered structure or a spinel structure, and a different additive element based on a lithium manganese composite oxide structure Examples thereof include complex oxides. In addition, as a phosphorus oxide containing lithium and a transition metal element, for example, a lithium iron phosphate compound (LiFePO ₄ ) having an olivine structure or a lithium iron manganese phosphate compound (LiFe _1-u Mn _u PO ₄ (u < 1)) and the like, and compounds containing different additive elements based on lithium iron phosphate structure.

  Examples of the binder include, but are not limited to, polyvinylidene fluoride, polytetrafluoroethylene, EPDM, SBR, NBR, fluororubber, and polyacrylic acid. The usage-amount of the said binder is about 0.1-20 mass% normally with respect to a positive electrode active material, Preferably it is 0.5-10 mass%.

  Examples of the conductive material include, but are not limited to, graphite fine particles, carbon black such as acetylene black and ketjen black, amorphous carbon fine particles such as needle coke, and carbon nanofibers. The usage-amount of the said electrically conductive material is about 5-60 mass% normally with respect to a positive electrode active material, Preferably it is 10-50 mass%.

  As the solvent for forming a slurry, an organic solvent or water that dissolves the binder is used. Examples of the organic solvent include N-methylpyrrolidone, dimethylformamide, dimethylacetamide, methyl ethyl ketone, cyclohexanone, methyl acetate, methyl acrylate, diethyltriamine, NN-dimethylaminopropylamine, ethylene oxide, tetrahydrofuran, and the like. However, the present invention is not limited to this. The usage-amount of the said solvent is about 25-400 mass% normally with respect to a positive electrode active material, Preferably it is 50-200 mass%.

  Usually, aluminum, stainless steel, nickel-plated steel, or the like is used for the positive electrode current collector.

  As the negative electrode, a negative electrode active material and a binder slurryed with an organic solvent or water is applied to a current collector and dried to form a sheet. When the polymer with a specific chemical structure moiety proposed in the present invention is used for the negative electrode, the polymer with the specific chemical structure moiety bonded, the negative electrode active material, and the binder are slurried with an organic solvent or water. The product is applied to a current collector, dried and used as a sheet.

  Examples of the negative electrode active material include lithium, lithium alloys, inorganic compounds such as tin / silicon compounds, titanium oxides, carbonaceous materials, and conductive polymers. In particular, a carbonaceous material that can occlude and release highly safe lithium ions is preferable. Although this carbonaceous material is not particularly limited, it is natural graphite, artificial, fullerene, graphite fiber chop, carbon nanotube, graphite whisker, highly oriented pyrolytic graphite, quiche graphite and other crystalline carbon, and petroleum-based coke, coal-based Coke, petroleum pitch carbide, coal pitch carbide, phenol resin / crystalline cellulose resin carbide, etc., and partially carbonized carbon, furnace black, acetylene black, pitch carbon fiber, PAN carbon fiber Etc.

Examples of the binder and the solvent to be slurried include the same as those for the positive electrode. The usage-amount of the said binder is about 0.1-20 mass% normally with respect to a negative electrode active material, Preferably it is about 0.5-10 mass%.
The usage-amount of the said solvent is about 50-200 mass% normally with respect to a negative electrode active material, Preferably it is 60-150 mass%.

  Usually, copper, nickel, stainless steel, nickel-plated steel, aluminum or the like is used for the current collector of the negative electrode.

  In this invention, as an organic solvent used for a non-aqueous electrolyte, what is normally used for the non-aqueous electrolyte can be used 1 type or in combination of 2 or more types. Specifically, it contains at least one selected from the group consisting of cyclic carbonate compounds, cyclic ester compounds, sulfone or sulfoxide compounds, amide compounds, chain carbonate compounds, chain or cyclic ether compounds, and chain ester compounds. It is preferable. In particular, it is preferable to contain one or more cyclic carbonate compounds and chain carbonate compounds, respectively. By using this combination, not only the cycle characteristics are excellent, but also the viscosity of the non-aqueous electrolyte, the electric capacity of the obtained battery, It is possible to provide a non-aqueous electrolyte secondary battery with a balanced output.

  In the present invention, the organic solvents used for the non-aqueous electrolyte are more specifically listed below. However, the organic solvent used in the present invention is not limited by the following examples.

  Since the cyclic carbonate compound, the cyclic ester compound, the sulfone or sulfoxide compound, and the amide compound have a high relative dielectric constant, they serve to increase the dielectric constant of the electrolytic solution. Specifically, examples of the cyclic carbonate compound include ethylene carbonate (EC), propylene carbonate (PC), 1,2-butylene carbonate, and isobutylene carbonate. Examples of the cyclic ester compound include γ-butyrolactone and γ-valerolactone. Examples of the sulfone or sulfoxide compound include sulfolane, sulfolene, tetramethylsulfolane, diphenyl sulfone, dimethyl sulfone, dimethyl sulfoxide, propane sultone, butylene sultone, and among these, sulfolanes are preferable. Examples of the amide compound include N-methylpyrrolidone, dimethylformamide, dimethylacetamide and the like.

  The chain carbonate compound, the chain or cyclic ether compound, and the chain ester compound can lower the viscosity of the non-aqueous electrolyte. Therefore, battery characteristics such as power density can be improved, such as the mobility of electrolyte ions can be increased. Moreover, since it is low-viscosity, the performance of the non-aqueous electrolyte at low temperatures can be increased. Specifically, as the chain carbonate compound, dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC), ethyl-n-butyl carbonate, methyl-t-butyl carbonate, di-i-propyl Examples thereof include carbonate and t-butyl-i-propyl carbonate. Examples of the linear or cyclic ether compounds include dimethoxyethane (DME), ethoxymethoxyethane, diethoxyethane, tetrahydrofuran, dioxolane, dioxane, 1,2-bis (methoxycarbonyloxy) ethane, 1,2-bis (ethoxycarbonyloxy). ) Ethane, 1,2-bis (ethoxycarbonyloxy) propane, ethylene glycol bis (trifluoroethyl) ether, i-propylene glycol (trifluoroethyl) ether, ethylene glycol bis (trifluoromethyl) ether, diethylene glycol bis (tri Fluoroethyl) ether and the like. Among these, dioxolanes are preferable. Examples of the chain ester compound include a carboxylic acid ester compound represented by the following general formula (4).

  In the general formula (4), n is an integer of 1 to 4, and R is an alkyl group having 1 to 4 carbon atoms (methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, tert-butyl). Specific examples include methyl formate, ethyl formate, methyl acetate, ethyl acetate, propyl acetate, sec-butyl acetate, butyl acetate, methyl propionate, ethyl propionate, and the like. The carboxylic acid ester compound represented by the general formula (4) has a low freezing point, and when further added to an organic solvent, particularly an organic solvent containing at least one cyclic carbonate compound and at least one chain carbonate compound, even at a low temperature. It is preferable because battery characteristics can be improved. The addition amount of the carboxylic acid ester compound represented by the general formula (4) is preferably 1 to 50% by volume in the organic solvent.

  In addition, acetonitrile, propionitrile, nitromethane, and derivatives thereof can also be used.

  In order to impart flame retardancy, halogen-based, phosphorus-based, and other flame retardants can be appropriately added to the non-aqueous electrolyte used in the present invention. Examples of the phosphorus flame retardant include phosphate esters such as trimethyl phosphate and triethyl phosphate.

  5-100 mass% is preferable with respect to the organic solvent which comprises the non-aqueous electrolyte of this invention, and, as for the addition amount of the said flame retardant, 10-50 mass% is especially preferable. If it is less than 5% by mass, sufficient flame retarding effect cannot be obtained.

In the present invention, a conventionally known electrolyte salt is used as the electrolyte salt used in the non-aqueous electrolyte. For example, LiPF ₆ , LiBF ₄ , LiAsF ₆ , LiCF ₃ SO ₃ , LiN (CF ₃ SO ₂ ) ₂ , _{LiC (CF 3 SO 2) 3} , LiB (CF 3 CO 2) 4, LiSbF 6, LiSiF 5, LiAlF 4, LiSCN, LiClO 4, LiCl, LiF, LiBr, LiI, LiAlF 4, LiAlCl 4, NaClO 4, NaBF ₄ , NaI, derivatives thereof and the like. 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 , LiB (CF ₃ CO ₂ ) ₄ , and derivatives of LiCF ₃ SO ₃ , derivatives of LiN (CF ₃ SO ₂ ) ₂ and LiC (CF _It is preferable to use one or more selected from the group consisting of ₃ SO ₂ ) ₃ derivatives because of excellent electrical characteristics.

  The electrolyte salt is added to the organic solvent so that the concentration in the non-aqueous electrolyte used in the present invention is 0.1 to 3.0 mol / liter, particularly 0.5 to 2.0 mol / liter. It is preferable to dissolve. If the concentration of the electrolyte salt is less than 0.1 mol / liter, a sufficient current density may not be obtained. If the concentration is more than 3.0 mol / liter, the stability of the nonaqueous electrolyte may be impaired. .

  Various additives can be appropriately added to the nonaqueous electrolytic solution used in the present invention for the purpose of reducing the irreversible capacity at the negative electrode and suppressing the decomposition reaction of the electrolytic solution at the negative electrode. They are mainly added to form a coating (SEI) on the negative electrode surface, and unsaturated carbonates such as vinylene carbonate, vinyl ethylene carbonate, diallyl carbonate, allyl ethyl carbonate, allyl methyl carbonate, dipropargyl carbonate, etc. Esters, sulfur compounds such as propane sultone, butane sultone, sulfolene, unsaturated esters such as dimethyl maleate, diethyl maleate, dimethyl fumarate, diethyl fumarate, dimethyl acetylenedicarboxylate, diethyl acetylenedicarboxylate, fluoroethylene carbonate, Halogenated carbonates such as chloroethylene carbonate, 4-trifluoromethyl-ethylene carbonate, tetravinylsilane, methyltrivinylsilane, dimethyldivinyli Silane, diethyldivinylsilane, trimethylvinylsilane, tetraallylsilane, triallylmethylsilane, diallyldimethylsilane, diallyldiethylsilane, allyltrimethylsilane and other unsaturated silane compounds, hexamethyldisilane, 1,2-divinyltetramethyldisilane and other disilanes And the like.

  Various additives can be appropriately added to the nonaqueous electrolytic solution used in the present invention for the purpose of suppressing the decomposition reaction of the electrolytic solution at the positive electrode. They mainly change the surface of the positive electrode to form a protective layer. 1,2-bis (fluorodimethylsilyl) ethane, 1,4-bis (fluorodimethylsilyl) -2-methylbutane, 1,6 -Bis (fluorodimethylsilyl) hexane, 1,4-bis (fluorodimethylsilyl) cyclohexane, fluoro-3-methoxypropyldimethylsilane, fluoro-3-ethoxypropyldimethylsilane, fluoro-3-propoxypropyldimethylsilane, fluorodimethyl Non-aromatic fluorosilane compounds such as vinylsilane, allylfluorodimethylsilane, crotylfluorodimethylsilane, 3-butenylfluorodimethylsilane, 1,1,3,3-tetramethyl-1,3-divinylsiloxane, 1,3-dimethyl-1,3-dipropy 1,3-vinylsiloxane, 1,3-diallyl-1,1,3,3-tetramethyl siloxane, an unsaturated siloxane compounds, and the like and the like.

In the non-aqueous electrolyte secondary battery of the present invention, a separator is used between the positive electrode and the negative electrode. As the separator, a commonly used polymer microporous film can be used without particular limitation. Examples of the film include polyethylene, polypropylene, polyvinylidene fluoride, polyvinylidene chloride, polyacrylonitrile, polyacrylamide, polytetrafluoroethylene, polysulfone, polyethersulfone, polycarbonate, polyamide, polyimide, polyethylene oxide and polypropylene oxide. Films composed of ethers, various celluloses such as carboxymethylcellulose and hydroxypropylcellulose, polymer compounds mainly composed of poly (meth) acrylic acid and various esters thereof, derivatives thereof, copolymers and mixtures thereof. Etc. These films may be used alone, or may be used as a multilayer film by superimposing these films. Furthermore, various additives may be used for these films, and the type and content thereof are not particularly limited. Among these films, a film made of polyethylene, polypropylene, polyvinylidene fluoride, or polysulfone is preferably used for the nonaqueous electrolyte secondary battery of the present invention.
These films are microporous so that the electrolyte can penetrate and ions can easily pass therethrough. The microporosity method includes a phase separation method in which a polymer compound and a solvent solution are formed into a film while microphase separation is performed, and the solvent is extracted and removed to make it porous. The film is extruded and then heat-treated, the crystals are aligned in one direction, and a gap is formed between the crystals by stretching to make it porous, and so on.

  In the non-aqueous electrolyte secondary battery of the present invention, the electrode material, the non-aqueous electrolyte, and the separator include a phenol-based antioxidant, a phosphorus-based antioxidant, and a thioether-based antioxidant for the purpose of improving safety. A hindered amine compound or the like may be added.

Examples of the phenol-based antioxidant include 1,6-hexamethylene bis [(3-tert-butyl-5-methyl-4-hydroxyphenyl) propionic acid amide], 4,4′-thiobis (6-tert. Tributyl-m-cresol), 4,4′-butylidenebis (6-tert-butyl-m-cresol), 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane 1,3,5-tris (2,6-dimethyl-3-hydroxy-4-tert-butylbenzyl) isocyanurate, 1,3,5-tris (3,5-ditert-butyl-4-hydroxybenzyl) ) Isocyanurate, 1,3,5-tris (3,5-ditert-butyl-4-hydroxybenzyl) -2,4,6-trimethylbenzene, tetrakis [3- (3,5-ditert-butyl- 4-hi Roxyphenyl) methyl propionate] methane, thiodiethylene glycol bis [(3,5-ditert-butyl-4-hydroxyphenyl) propionate], 1,6-hexamethylenebis [(3,5-ditert-butyl-4 -Hydroxyphenyl) propionate], bis [3,3-bis (4-hydroxy-3-tert-butylphenyl) butyric acid] glycol ester, bis [2-tert-butyl-4-methyl-6- (2- Hydroxy-3-tert-butyl-5-methylbenzyl) phenyl] terephthalate, 1,3,5-tris [(3,5-ditert-butyl-4-hydroxyphenyl) propionyloxyethyl] isocyanurate, 3,9 -Bis [1,1-dimethyl-2-{(3-tert-butyl-4-hydroxy-5-methylphenyl) propioni Ruoxy} ethyl] -2,4,8,10-tetraoxaspiro [5,5] undecane, triethylene glycol bis [(3-tert-butyl-4-hydroxy-5-methylphenyl) propionate] and the like. When adding to an electrode material, it is preferable to use 0.01-10 mass parts with respect to 100 mass parts of electrode materials, especially 0.05-5 mass parts.

  Examples of the phosphorus antioxidant include trisnonylphenyl phosphite, tris [2-tert-butyl-4- (3-tert-butyl-4-hydroxy-5-methylphenylthio) -5-methylphenyl]. Phosphite, tridecyl phosphite, octyl diphenyl phosphite, di (decyl) monophenyl phosphite, di (tridecyl) pentaerythritol diphosphite, di (nonylphenyl) pentaerythritol diphosphite, bis (2,4-di Tert-butylphenyl) pentaerythritol diphosphite, bis (2,6-ditert-butyl-4-methylphenyl) pentaerythritol diphosphite, bis (2,4,6-tritert-butylphenyl) pentaerythritol diphosphite Phosphite, bis (2,4-dicumylphenyl) pen Erythritol diphosphite, tetra (tridecyl) isopropylidene diphenol diphosphite, tetra (tridecyl) -4,4′-n-butylidenebis (2-tert-butyl-5-methylphenol) diphosphite, hexa (tridecyl) -1 , 1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane triphosphite, tetrakis (2,4-ditert-butylphenyl) biphenylene diphosphonite, 9,10-dihydro-9 -Oxa-10-phosphaphenanthrene-10-oxide, 2,2'-methylenebis (4,6-tert-butylphenyl) -2-ethylhexyl phosphite, 2,2'-methylenebis (4,6- Tributylphenyl) -octadecyl phosphite, 2,2′-ethylidenebis (4,6- Tert-butylphenyl) fluorophosphite, tris (2-[(2,4,8,10-tetrakis tert-butyldibenzo [d, f] [1,3,2] dioxaphosphin-6-yl) Oxy] ethyl) amine, phosphite of 2-ethyl-2-butylpropylene glycol and 2,4,6-tritert-butylphenol, and the like.

  Examples of the thioether-based antioxidant include dialkylthiodipropionates such as dilauryl thiodipropionate, dimyristyl thiodipropionate, and distearyl thiodipropionate, and pentaerythritol tetra (β-alkylmercaptopropionate esters). Is mentioned.

  Examples of the hindered amine compound include 2,2,6,6-tetramethyl-4-piperidyl stearate, 1,2,2,6,6-pentamethyl-4-piperidyl stearate, 2,2,6,6. -Tetramethyl-4-piperidylbenzoate, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, tetrakis (2,2,6,6-tetramethyl-4-piperidyl) -1,2, 3,4-butanetetracarboxylate, tetrakis (1,2,2,6,6-pentamethyl-4-piperidyl) -1,2,3,4-butanetetracarboxylate, bis (2,2,6,6) -Tetramethyl-4-piperidyl) -di (tridecyl) -1,2,3,4-butanetetracarboxylate, bis (1,2,2,6,6-pentamethyl-4-pi Lysyl) .di (tridecyl) -1,2,3,4-butanetetracarboxylate, bis (1,2,2,4,4-pentamethyl-4-piperidyl) -2-butyl-2- (3,5 -Di-tert-butyl-4-hydroxybenzyl) malonate, 1- (2-hydroxyethyl) -2,2,6,6-tetramethyl-4-piperidinol / diethyl succinate polycondensate, 1,6- Bis (2,2,6,6-tetramethyl-4-piperidylamino) hexane / 2,4-dichloro-6-morpholino-s-triazine polycondensate, 1,6-bis (2,2,6,6 -Tetramethyl-4-piperidylamino) hexane / 2,4-dichloro-6-tert-octylamino-s-triazine polycondensate, 1,5,8,12-tetrakis [2,4-bis (N-butyl) -N- (2,2,6, -Tetramethyl-4-piperidyl) amino) -s-triazin-6-yl] -1,5,8,12-tetraazadodecane, 1,5,8,12-tetrakis [2,4-bis (N- Butyl-N- (1,2,2,6,6-pentamethyl-4-piperidyl) amino) -s-triazin-6-yl] -1,5,8-12-tetraazadodecane, 1,6,11 -Tris [2,4-bis (N-butyl-N- (2,2,6,6-tetramethyl-4-piperidyl) amino) -s-triazin-6-yl] aminoundecane, 1,6,11 Hindered amine compounds such as tris [2,4-bis (N-butyl-N- (1,2,2,6,6-pentamethyl-4-piperidyl) amino) -s-triazin-6-yl] aminoundecane Can be mentioned.

  The shape of the non-aqueous electrolyte secondary battery of the present invention having the above configuration is not particularly limited, and can be various shapes such as a coin shape, a cylindrical shape, and a square shape. FIG. 1 shows an example of a coin-type battery of the nonaqueous electrolyte secondary battery of the present invention, and FIGS. 2 and 3 show examples of a cylindrical battery, respectively.

  In the coin-type nonaqueous electrolyte secondary battery 10 shown in FIG. 1, 1 is a positive electrode, 1a is a positive electrode current collector, 2 is a negative electrode made of a carbonaceous material capable of inserting and extracting lithium ions released from the positive electrode, 2a Is a negative electrode current collector, 3 is a non-aqueous electrolyte, 4 is a positive electrode case made of stainless steel, 5 is a negative electrode case made of stainless steel, 6 is a gasket made of polypropylene, and 7 is a separator made of polyethylene.

  2 and 3, 11 is a negative electrode, 12 is a negative electrode assembly, 12 is a negative electrode assembly, 13 is a positive electrode, 14 is a positive electrode current collector, and 15 is a nonaqueous electrolyte solution. , 16 is a separator, 17 is a positive electrode terminal, 18 is a negative electrode terminal, 19 is a negative electrode plate, 20 is a negative electrode lead, 21 is a positive electrode plate, 22 is a positive electrode lead, 23 is a case, 24 is an insulating plate, 25 is a gasket, 26 is A safety valve 27 is a PTC element.

  Hereinafter, the present invention will be described in detail by way of examples. However, the present invention is not limited to the following examples.

<New polymer>
Example 1 Preparation of Polymer (Compound No. 2) 15.4 g of isobutylene / maleic anhydride copolymer (ISOBAM) having a weight average molecular weight of 90,000 and 200 ml of dimethylacetamide at 60 ° C. in a flask equipped with a reflux condenser. After dissolving by stirring for minutes, 7.61 g of salicylhydrazide was added and refluxed at 63 ° C. for 18 hours. The reaction solution was dropped into 1 liter of an aqueous solution of methanol / water (1/1) to precipitate a polymer, and then 17.8 of a purple polymer was obtained by filtration and drying. The yield was 78%. The obtained polymer was dissolved in heated THF, NMP, DMF, and the like, but there was no solvent dissolved at room temperature.
17.8 g of the obtained polymer and 4.89 g of lithium hydroxide monohydrate were dissolved in 167 ml of water by stirring, and the compound no. 190 g of a 10% by weight aqueous solution of 2 was obtained. The pH of the aqueous solution was 9. The polymer obtained by drying the aqueous solution was analyzed by IR analysis to obtain the target compound No. 2 was confirmed. The IR analysis results are shown below.
(IR analysis results)
^{1722cm -1, 1700cm -1, 1687cm -1} , 1561cm -1, 1548cm -1, 1455 cm -1, 1400 cm -1, 1328 cm -1, 1257 cm -1, 1151 cm -1, 760 cm -1

Example 2 Production of Polymer (Compound No. 4) 15.6 g of methyl vinyl ether / maleic anhydride copolymer (VEMA) having a weight average molecular weight of 1,080,000 and 200 ml of THF at 40 ° C. for 10 minutes in a flask equipped with a reflux condenser. After dissolving by stirring, 7.61 g of salicylhydrazide was added and refluxed at 63 ° C. for 2 hours. The reaction solution was added dropwise to 1 liter of an aqueous solution of methanol / water (2/5) to precipitate a polymer, and then 19.8 of a purple polymer was obtained by filtration and drying. The yield was 88%. The obtained polymer was dissolved in heated THF, NMP, DMF, and the like, but there was no solvent dissolved at room temperature.
19.8 g of the obtained polymer and 6.89 g of lithium hydroxide monohydrate were dissolved in 181 ml of water by stirring, and the compound no. 4 was obtained in an amount of 208 g. The pH of the aqueous solution was 8.
The polymer obtained by drying the aqueous solution was analyzed by IR analysis to obtain the target compound No. 4 was confirmed. The IR analysis results are shown below.
(IR analysis results) 1595 cm ⁻¹ , 1473 cm ⁻¹ , 1401 cm ⁻¹ , 1327 cm ⁻¹ , 1253 cm ⁻¹ , 1192 cm ⁻¹ , 1078 cm ⁻¹ , 756 cm ⁻¹

Example 3 Production of Polymer (Compound No. 9) 15.6 g of methyl vinyl ether / maleic anhydride copolymer (VEMA) having a weight average molecular weight of 1.80 million, 12.5 g of taurine, lithium hydroxide monohydrate 4 g, 160 ml of N, N-dimethylacetamide and 400 ml of water were stirred at 102 ° C. in a flask equipped with a distiller, and water was distilled off over 4 hours. The reaction solution was heated under reduced pressure to distill off N, N-dimethylacetamide and then dried under reduced pressure to obtain 28.1 g of a solid. This solid was dissolved in 260 ml of water, liquid-separated with 260 ml of chloroform, and then the aqueous layer was dried under reduced pressure to obtain 26.8 g of taurine-bound blue-green polymer. The yield was 95%. The obtained polymer was dissolved in heated NMP, DMF, and the like, but there was no solvent that dissolved at room temperature.
26.8 g of the obtained polymer was dissolved in 241 ml of water by stirring, and Compound No. 268 g of a 10% by mass aqueous solution of 9 was obtained. The pH of the aqueous solution was 8.
The polymer obtained by drying the aqueous solution was analyzed by IR analysis to obtain the target compound No. 9 was confirmed. The IR analysis results are shown below.
(IR analysis results) 1694 cm ⁻¹ , 1575 cm ⁻¹ , 1409 cm ⁻¹ , 1049 cm ⁻¹

<Nonaqueous electrolyte secondary battery>
Example 4
1. Production of Positive Electrode 85 parts by mass of LiMn ₂ O ₄ as a positive electrode active material, 10 parts by mass of acetylene black as a conductive material, and 5 parts by mass of polyvinylidene fluoride (PVDF) as a binder were mixed to obtain a positive electrode material. This positive electrode material was dispersed in N-methyl-2-pyrrolidone (NMP) to form a slurry. This slurry was applied to both surfaces of an aluminum positive electrode current collector, dried, and press-molded to obtain a positive electrode plate. Then, this positive electrode plate was cut into a predetermined size to produce a disc-shaped positive electrode.

2. Production of Negative Electrode 98 parts by mass of artificial graphite as a negative electrode active material, 1 part by mass of sodium carboxymethylcellulose (CMC), and compound No. 1 produced in Example 1 were prepared. 9.8 parts by mass of a 10% by mass aqueous solution of No. 2 was dispersed in 88 parts by mass of water, and 1 part by mass of styrene butadiene rubber (SBR) was added and dispersed to obtain a slurry. This slurry was applied to a copper negative electrode current collector, dried and press-molded to obtain a negative electrode plate. Then, this negative electrode plate was cut into a predetermined size to produce a disc-shaped negative electrode.

3. Preparation of nonaqueous electrolyte solution LiPF ₆ was dissolved at a concentration of 1.0 mol / liter in a mixed solvent consisting of 30% by volume of ethylene carbonate, 40% by volume of ethyl methyl carbonate, and 30% by volume of dimethyl carbonate, and a hydrate was obtained. 0.05 parts by weight of MnClO ₄ obtained by vacuum drying at 100 ° C. for 2 hours and 0.50 parts by weight of vinylene carbonate as an additive were added to obtain a non-aqueous electrolyte.

4). Assembling the Battery The obtained disc-shaped positive electrode and disc-shaped negative electrode were held in a case with a polyethylene microporous film having a thickness of 25 μm interposed therebetween. Thereafter, a non-aqueous electrolyte was poured into the case, and the case was sealed and sealed to produce a coin-type lithium secondary battery having a diameter of 20 mm and a thickness of 3.2 mm.

Example 5
In the preparation of the negative electrode, Compound No. Instead of the compound No. 2 prepared in Example 2, A coin-type lithium secondary battery was manufactured in the same manner as in Example 4 except that 4 was added.

Example 6
In the preparation of the negative electrode, Compound No. Instead of the compound No. 2 prepared in Example 3, A coin-type lithium secondary battery was manufactured in the same manner as in Example 4 except that 9 was added.

Comparative Example 98 parts by weight of artificial graphite as a negative electrode active material and 1 part by weight of carboxymethylcellulose sodium salt (CMC) were dispersed in 88 parts by weight of water, and 1 part by weight of styrene butadiene rubber (SBR) was added and dispersed therein. It was. This slurry was applied to a copper negative electrode current collector, dried and press-molded to obtain a negative electrode plate. Thereafter, this positive electrode plate was cut into a predetermined size to produce a disc-shaped negative electrode for comparison.
A coin-type lithium secondary battery was manufactured in the same manner as in Example 4 except that this comparative disk-shaped negative electrode was used.

  About the coin-type lithium ion battery produced in Examples 4-6 and the comparative example, the initial stage characteristic test and the cycle characteristic test in 60 degreeC were done. In the initial characteristic test, the discharge capacity ratio (%) and the internal resistance ratio (%) were obtained. In the cycle characteristic test at 60 ° C., the discharge capacity recovery rate (%) and the internal resistance increase rate (%) were determined. The test results are shown in [Table 1]. The test methods for the initial characteristic test and the cycle characteristic test are as follows.

<Initial characteristic test>
1. Method of measuring discharge capacity ratio A lithium ion battery is placed in a constant temperature bath with an atmospheric temperature of 20 ° C., and charged at a constant current and a constant voltage up to 4.2 V at a charging current of 0.3 mA / cm ² (current value equivalent to 0.2 C). Then, the operation of discharging a constant current to 3.0 V at a discharge current of 0.3 mA / cm ² (current value corresponding to 0.2 C) was performed five times. Then, the charging current 0.3mA / cm ² (0.2C equivalent current value) 4.2 V to a constant current constant voltage charging, the discharge current 0.3 mA / cm ² 3 in (0.2 C equivalent current value) A constant current was discharged to 0.0 V, and the discharge capacity at the sixth cycle was defined as the initial discharge capacity. From this initial discharge capacity, the discharge capacity ratio (%) was determined according to the following formula. The measurement was performed in an atmosphere at 20 ° C.
Discharge capacity ratio (%) = [(initial discharge capacity) / (initial discharge capacity in Example 4)] × 100

2. Measurement method of internal resistance ratio First, each lithium secondary battery whose initial discharge capacity was measured was charged at a constant current and a constant voltage up to 3.75 V at a charging current of 1.5 mA / cm ² (current value equivalent to 1 C). Using an impedance measurement device (mobile measurement station CompactStat), scanning was performed from a frequency of 100 kHz to 0.02 Hz, and a Cole-Cole plot was created, in which the vertical axis represents the imaginary part and the horizontal axis represents the real part. Subsequently, in this Cole-Cole plot, the arc portion was fitted with a circle, and the larger one of the two points intersecting the real portion of this circle was used as the initial internal resistance. From this initial internal resistance, the internal resistance ratio (%) was determined according to the following formula.
Internal resistance ratio (%) = “(initial internal resistance) / (initial internal resistance in Example 4)” × 100

<Cycle characteristic test method>
1. Measuring method of discharge capacity recovery rate The battery after the initial characteristic test was measured was placed in a thermostatic chamber at an atmospheric temperature of 60 ° C., and a charging current of 1.5 mA / cm ² (current value equivalent to 1 C, 1 C represents the battery capacity of 1 The current was discharged at a constant current) to 4.2V, and the cycle of discharging at a discharge current of 1.5 mA / cm ² (current value equivalent to 1C) to 3.0V was repeated 500 times. . Thereafter, the ambient temperature is returned to 20 ° C., and constant current and constant voltage charging is performed up to 4.2 V with a charging current of 0.3 mA / cm ² (current value corresponding to 0.2 C), and a discharge current of 0.3 mA / cm ² (0 The discharge capacity at this time was defined as the discharge capacity after the cycle test. From the discharge capacity after this cycle test and the initial discharge capacity, the discharge capacity recovery rate (%) was determined according to the following formula.
Discharge capacity recovery rate (%) = [(discharge capacity after cycle test) / (initial discharge capacity)] × 100

In the method for measuring the discharge capacity recovery rate, the internal resistance at 20 ° C. of the lithium secondary battery after the cycle was repeated 500 times was measured in the same manner as the method for measuring the internal resistance ratio. The internal resistance after the cycle was used. From the internal resistance after this cycle and the initial internal resistance, the rate of increase in internal resistance (%) was determined according to the following formula.
Internal resistance increase rate (%) = “(internal resistance after cycle−initial internal resistance) / (initial internal resistance)] × 100

DESCRIPTION OF SYMBOLS 1 Positive electrode 1a Positive electrode collector 2 Negative electrode 2a Negative electrode collector 3 Electrolyte 4 Positive electrode case 5 Negative electrode case 6 Gasket 7 Separator 10 Coin type nonaqueous electrolyte secondary battery 10 'Cylindrical type nonaqueous electrolyte secondary battery 11 Negative electrode 12 Negative electrode assembly 13 Positive electrode 14 Positive electrode assembly 15 Non-aqueous electrolyte 16 Separator 17 Positive electrode terminal 18 Negative electrode terminal 19 Negative electrode plate 20 Negative electrode lead 21 Positive electrode 22 Positive electrode lead 23 Case 24 Insulating plate 25 Gasket 26 Safety valve 27 PTC element

Claims (6)

The following general formula (A)

(Wherein R ₁ , R ₂ , R ₃ and R ₄ each independently represents any one of a hydrogen atom, a methyl group or a methoxy group, R ₅ is an alkyl group having 1 to 6 carbon atoms and 1 carbon atom) -6 represents an alkoxy group, a hydroxyl group, or a hydrogen atom, and M ₁ represents hydrogen, lithium, sodium, or potassium.)
A structural unit represented by
The following general formula (B)

(In the formula, R ₁ , R ₂ , R ₃ , R ₄ and M ₁ have the same meaning as in the general formula (A).)
And a structural unit represented by the formula: The following general formula (C)

(In the formula, R ₁ , R ₂ , R ₃ , R ₄ and M ₁ have the same meaning as in the general formula (A), and R ₆ represents an alkylene group having 2 to ₆ carbon atoms.)
A structural unit represented by
The following general formula (B)

(In the formula, R ₁ , R ₂ , R ₃ , R ₄ and M ₁ have the same meaning as in the general formula (A).)
And a structural unit represented by the formula: The polymer of Claim 1 represented by following General formula (1).

(In the formula, R ₁ , R ₂ , R ₃ , R ₄ , R ₅ and M ₁ have the same meaning as in the general formula (A), m and n are m + n is 5 or more, and m / n Is a number that is 1/99 or more and 99/1 or less.) The polymer of Claim 2 represented by following General formula (2).

(In the formula, R ₁ , R ₂ , R ₃ , R ₄ and M ₁ are synonymous with the above general formula (A), R ₆ is synonymous with the above general formula (C), and m and n are And is synonymous with the above general formula (1).)   The nonaqueous electrolyte secondary battery which contains the polymer of any one of Claims 1-4 in an electrode.   The nonaqueous electrolyte secondary battery according to claim 5, comprising a transition metal composite oxide containing Mn as an electrode active material.

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