JP5764526B2 - Non-aqueous secondary battery electrolyte and secondary battery - Google Patents

Description

  The present invention relates to an electrolyte solution for a non-aqueous secondary battery containing an organic solvent, and a secondary battery using the same.

  Recently, secondary batteries called lithium ion batteries, which are attracting attention, use secondary batteries (so-called lithium ion secondary batteries) that use insertion and extraction of lithium in charge and discharge reactions, and precipitation and dissolution of lithium. They are roughly classified into secondary batteries (so-called lithium metal secondary batteries). These can obtain a large energy density as compared with lead batteries and nickel cadmium batteries. Utilizing this characteristic, in recent years, it has become widespread as a power source for portable electronic devices such as a camera-integrated VTR (video tape recorder), a mobile phone, or a notebook personal computer. In connection with this, development of a lithium ion secondary battery that is particularly lightweight and capable of obtaining a high energy density is underway. Further, there is a strong demand for miniaturization, weight reduction, long life, and high safety.

  As an electrolytic solution of a lithium ion secondary battery or a lithium metal secondary battery (hereinafter collectively referred to simply as a lithium ion secondary battery), the conductivity is high and the potential is stable. A combination of a carbonate ester solvent such as propylene carbonate or diethyl carbonate and an electrolyte salt such as lithium hexafluorophosphate is widely used.

With respect to the composition of the electrolytic solution, a technique for incorporating various additives into the electrolytic solution has been proposed for the purpose of improving cycle characteristics and the like. For example, in Patent Documents 1 and 2, vinylene carbonate (hereinafter abbreviated as VC) is used to suppress deterioration in charge / discharge cycle characteristics due to decomposition of a carbonic acid ester used as an electrolytic solution at a negative electrode. ) And vinyl ethylene carbonate (hereinafter abbreviated as VEC) are added to the electrolytic solution, and VC, VEC, etc. are electropolymerized on the negative electrode to form a negative electrode protection film (hereinafter abbreviated as SEI). It has been proposed to form. These additives are classified as so-called anionic polymerizable monomers. Besides, styrene or a derivative thereof (Patent Document 3), isoprene, 2-vinylpyridine, ethyl cinnamate, methyl cinnamate, ionone, It has been proposed to use myrcene or the like (Patent Document 4), phenyl vinylene carbonate (Patent Document 5) or the like as an additive.
Patent Document 6 discloses that an SEI formed from an anion polymerizable monomer such as isoprene, 2-vinylpyridine, acrylic acid, methacrylic acid, styrene, butadiene, acrylonitrile by using a compound capable of chelating with lithium ions. It has been proposed that the properties of
As means for efficiently polymerizing an anion polymerization monomer, Patent Document 7 proposes to use bromobenzene together. In this document, a mechanism is proposed in which phenyllithium produced by the reaction of lithium metal deposited on an overcharged negative electrode with bromobenzene serves as a polymerization initiator for styrene or isoprene and SEI is formed on the negative electrode. .

JP 2003-151621 A JP 2003-031259 A JP 2004-103372 A Japanese Patent No. 3,163,078 Japanese Patent No. 3,837,914 Japanese Patent No. 4,050,251 Japanese Patent Laid-Open No. 11-97059

However, in general, the reduction potential of the above-mentioned anionic polymerizable monomer is base (low potential) and also has a low electrochemical reduction activity, so polymerization starting from direct electron transfer on the negative electrode is not possible. Very slow. Actually, in the electrochemical measurement system, styrene and VC do not show a clear reduction current when the potential with respect to lithium is in the range of 0V to 2.5V.
On the other hand, as described above, Patent Document 7 proposes to use bromobenzene together, but the overcharged state in which the effect is recognized is an abnormal state in the battery. SEI formation is not performed during normal battery operation.

  As described above, there are examples in which an anionic polymerization monomer is used as an additive for a battery, but a technique for efficiently polymerizing these on a negative electrode under normal use conditions other than an overcharged state or the like to form SEI is known. Not. Therefore, even if these anionic polymerizable monomers are used as additives, the effect of improving the cycle characteristics is limited to a certain range and is insufficient. On the other hand, if the addition amount of the anionic polymerizable monomer is simply increased in order to improve the effect of improving the cycle characteristics, the internal resistance of the battery is increased, the initial characteristics of the battery are deteriorated, and the essential problem cannot be solved.

  The present invention has been made in view of such problems, and an object thereof is to provide a non-aqueous electrolyte excellent in all of initial capacity, cycle characteristics, and charge storage stability, and a secondary battery using the non-aqueous electrolyte. There is.

  As a result of earnest research in view of the above problems, the present inventor has combined an anion polymerizable monomer and a compound having a high electrochemical reduction activity as a second additive, a so-called redox compound, so that the battery can be added even in a small amount. It has been found that the cycle characteristics can be significantly improved. This is considered to be based on a mechanism in which the second additive having a high electrode electron transfer rate accepts electrons from the negative electrode, and the reduced product serves as a polymerization initiator for the anionic polymerizable monomer. That is, since the reduction potential of the second additive is within the range of the negative electrode operating potential, it becomes possible to proceed with the SEI formation by the anion polymerizable monomer at the normal battery operating potential, which is highly effective in improving performance such as cycle characteristics. It is thought that was demonstrated.

The electrolyte solution for a non-aqueous secondary battery of the present invention that has solved the above problems is an electrolyte solution containing an anion polymerizable monomer, a polymerization initiator precursor, and an organic solvent, and the polymerization initiator precursor is (A) a compound represented by the following general formula (1 ′), (B) a compound represented by the following general formula (2), or (C) a potential of 0 to 1.9 V on the negative electrode (in terms of lithium) in compound reduced state, and are one of the amount of the anionic polymerizable monomer wherein the polymerization initiator precursor, Ru der respectively 0.001mol / l or 0.1 mol / l or less.

（一般式（１’）のＲ^１０１及びＲ^１０２は、芳香族基または複素芳香族基を表す。Ｒ^１０１とＲ^１０２は、直接あるいは連結基を介して結合し、式（１’）のＣ＝Ｏを含む５〜８員環を形成する。
一般式（２）のＲ^１０３及びＲ^１０４は、芳香族基または複素芳香族基を表す。Ｒ^１０３とＲ^１０４は、直接あるいは連結基を介して結合し、式（２）の−Ｃ（＝Ｏ）Ｃ（＝Ｏ）−を含む６〜８員環を形成してもよい。
一般式（１’）または（２）で表される化合物は、複数のものが結合して多量体を構成していてもよい。）
好ましくは、（Ｃ）化合物が、下記一般式（１）で表される化合物である。

(R ¹⁰¹ and R ¹⁰² in the general formula (1 ′) represent an aromatic group or a heteroaromatic group. R ¹⁰¹ and R ¹⁰² are bonded directly or via a linking group, and the C in the formula (1 ′) Forms a 5- to 8-membered ring containing ═O.
R ¹⁰³ and R ^{104 in} the general formula (2) represent an aromatic group or a heteroaromatic group. R ¹⁰³ and R ¹⁰⁴ may be bonded directly or via a linking group to form a 6-8 membered ring containing —C (═O) C (═O) — in the formula (2).
A plurality of compounds represented by the general formula (1 ′) or (2) may be combined to form a multimer. )
Preferably, the compound (C) is a compound represented by the following general formula (1).

（一般式（１）のＲ^１及びＲ^２は、芳香族基または複素芳香族基を表す。Ｒ^１とＲ^２は、直接あるいは連結基を介して結合し、式（１）のＣ＝Ｏを含む５〜８員環を形成してもよい。
一般式（１）で表される化合物は、複数のものが結合して多量体を構成していてもよい。）

(R ¹ and R ^{2 in} the general formula (1) represent an aromatic group or a heteroaromatic group. R ¹ and R ² are bonded directly or via a linking group, and C = O in the formula (1) A 5- to 8-membered ring containing
A plurality of compounds represented by the general formula (1) may be combined to form a multimer. )

  More preferably, the polymerization initiator precursor is a compound represented by the following general formula (1) or (2).

（一般式（１）のＲ^１及びＲ^２は、芳香族基または複素芳香族基を表す。Ｒ^１とＲ^２は、直接あるいは連結基を介して結合し、式（１）のＣ＝Ｏを含む５〜８員環を形成してもよい。
ただし、式（１）で表される化合物が、負極上において電位１．９Ｖ超（対リチウム換算）で還元される化合物である場合は、Ｒ^１とＲ^２は式（１）のＣ＝Ｏを含む５〜８員環を形成する。
一般式（２）のＲ^１０３及びＲ^１０４は、芳香族基または複素芳香族基を表す。Ｒ^１０３とＲ^１０４は、直接あるいは連結基を介して結合し、式（２）の−Ｃ（＝Ｏ）Ｃ（＝Ｏ）−を含む６〜８員環を形成してもよい。
一般式（１）または（２）で表される化合物は、複数のものが結合して多量体を構成していてもよい。）

(R ¹ and R ^{2 in} the general formula (1) represent an aromatic group or a heteroaromatic group. R ¹ and R ² are bonded directly or via a linking group, and C = O in the formula (1) A 5- to 8-membered ring containing
However, when the compound represented by the formula (1) is a compound that is reduced on the negative electrode at a potential exceeding 1.9 V (vs. lithium), R ¹ and R ² are C═O in the formula (1). 5 to 8 membered ring is formed.
R ¹⁰³ and R ^{104 in} the general formula (2) represent an aromatic group or a heteroaromatic group. R ¹⁰³ and R ¹⁰⁴ may be bonded directly or via a linking group to form a 6-8 membered ring containing —C (═O) C (═O) — in the formula (2).
A plurality of compounds represented by general formula (1) or (2) may be combined to form a multimer. )

  More preferably, the anion polymerizable monomer is at least one of compounds represented by the following general formulas (3-a) to (3-d).

(In General Formula (3-a), R ³ represents a hydrogen atom or an alkyl group. R ⁴ represents an aromatic group, a heterocyclic group, a nitrile group, an alkoxy group, or an acyloxy group.)
(In General Formula (3-b), R ⁵ represents a hydrogen atom, an alkyl group, or a cyano group. R ⁶ represents an alkyl group or an alkoxy group.)
(In the general formula (3-c), R ⁷ and R ⁸ represent a hydrogen atom, an alkyl group or an aromatic group. X, Y, and Z are independently —O—, —S—, —C (= O) -, - C (= S) -, - N (R) -, - S (O) - and -SO ₂ - represents a divalent linking group selected from, R represents an alkyl group or an aromatic group Represents.)
(In the general formula (3-d), R ⁹ represents an alkyl group or a hydrogen atom.)
(The compounds represented by the general formulas (3-a) to (3-d) may form multimers linked to each other at R ^{3 to} R ⁹ ).
More preferably, the polymerization initiator precursor is a 9-fluorenone compound, anthrone compound, xanthone compound, dibenzosuberone compound, dibenzosuberone compound, anthraquinone compound, biantronyl compound, biantron compound, substituted benzophenone compound, dibenzoyl compound, and It is at least one selected from the group consisting of these derivatives.
More preferably, the polymerization initiator precursor is at least one selected from the group consisting of compounds represented by the following formulas (1-1) to (1-27) or derivatives thereof.

(General formula (1-24) is a 4-fluoro product or a 4,4′-difluoro product.)
More preferably, the polymerization initiator precursor is represented by the formulas (1-1) to (1-12), (1-15) to (1-23), (1-26) and (1-27). Or at least one selected from the group consisting of derivatives thereof.
More preferably, the anionic polymerizable monomer, an aromatic substituted vinyl compounds, vinylene carbonate compound, or Ru least any one Tsudea acrylic compound.
Preferably the is found, the electrolytic solution further comprises a metal ion or a salt thereof belonging to the family or group II of the periodic table.
The nonaqueous electrolyte secondary battery of the present invention includes an electrolyte for a nonaqueous secondary battery of the present invention, a positive electrode capable of inserting and releasing ions of metals belonging to Group 1 or Group 2 of the periodic table, and the ions A negative electrode capable of insertion / release or dissolution / precipitation.
Preferably, lithium titanate is applied as the negative electrode active material.
The present invention is a kit for an electrolyte solution for a non-aqueous secondary battery using a mixture of a first agent and a second agent,
The first agent contains an ion of a metal belonging to Group 1 or Group 2 of the periodic table or a metal salt containing the same, the second agent contains an anion polymerizable monomer, and (A) the following general formula (1 ′ ), (B) a compound represented by the following general formula (2), or (C) a compound reduced on the negative electrode at a potential of 0 to 1.9 V (vs. lithium). The polymerization initiator precursor is added to at least one of the first agent, the second agent, and the other agent, and the anionic polymerizable monomer and the polymerization initiator precursor are added after mixing. Also included is a kit of an electrolyte solution for a non-aqueous secondary battery , which is added so that the amount is 0.001 mol / l or more and 0.1 mol / l or less, respectively .

（一般式（１’）のＲ^１０１及びＲ^１０２は、芳香族基または複素芳香族基を表す。Ｒ^１０１とＲ^１０２は、直接あるいは連結基を介して結合し、式（１’）のＣ＝Ｏを含む５〜８員環を形成する。
一般式（２）のＲ^１０３及びＲ^１０４は、芳香族基または複素芳香族基を表す。Ｒ^１０３とＲ^１０４は、直接あるいは連結基を介して結合し、式（２）の−Ｃ（＝Ｏ）Ｃ（＝Ｏ）−を含む６〜８員環を形成してもよい。
一般式（１’）または（２）で表される化合物は、複数が結合して多量体を構成していてもよい。
好ましくは、（Ｃ）化合物が、下記一般式（１）で表される化合物である。

(R ¹⁰¹ and R ¹⁰² in the general formula (1 ′) represent an aromatic group or a heteroaromatic group. R ¹⁰¹ and R ¹⁰² are bonded directly or via a linking group, and the C in the formula (1 ′) Forms a 5- to 8-membered ring containing ═O.
R ¹⁰³ and R ^{104 in} the general formula (2) represent an aromatic group or a heteroaromatic group. R ¹⁰³ and R ¹⁰⁴ may be bonded directly or via a linking group to form a 6-8 membered ring containing —C (═O) C (═O) — in the formula (2).
A plurality of the compounds represented by the general formula (1 ′) or (2) may be combined to form a multimer.
Preferably, the compound (C) is a compound represented by the following general formula (1).

（一般式（１）のＲ^１及びＲ^２は、芳香族基または複素芳香族基を表す。Ｒ^１とＲ^２は、直接あるいは連結基を介して結合し、式（１）のＣ＝Ｏを含む５〜８員環を形成してもよい。

(R ¹ and R ^{2 in} the general formula (1) represent an aromatic group or a heteroaromatic group. R ¹ and R ² are bonded directly or via a linking group, and C = O in the formula (1) A 5- to 8-membered ring containing

  More preferably, the polymerization initiator precursor contained in at least one of the first agent, the second agent, and the other agent is any one of the compounds represented by the following general formula (1) or (2). It is.

（一般式（１）のＲ^１及びＲ^２は、芳香族基または複素芳香族基を表す。Ｒ^１とＲ^２は、直接あるいは連結基を介して結合し、式（１）のＣ＝Ｏを含む５〜８員環を形成してもよい。
ただし、式（１）で表される化合物が、負極上において電位１．９Ｖ超（対リチウム換算）で還元される化合物である場合は、Ｒ^１とＲ^２は式（１）のＣ＝Ｏを含む５〜８員環を形成する。
一般式（２）のＲ^１０３及びＲ^１０４は、芳香族基または複素芳香族基を表す。Ｒ^１０３とＲ^１０４は、直接あるいは連結基を介して結合し、式（２）の−Ｃ（＝Ｏ）Ｃ（＝Ｏ）−を含む６〜８員環を形成してもよい。
一般式（１）または（２）で表される化合物は、複数のものが結合して多量体を構成していてもよい。）

(R ¹ and R ^{2 in} the general formula (1) represent an aromatic group or a heteroaromatic group. R ¹ and R ² are bonded directly or via a linking group, and C = O in the formula (1) A 5- to 8-membered ring containing
However, when the compound represented by the formula (1) is a compound that is reduced on the negative electrode at a potential exceeding 1.9 V (vs. lithium), R ¹ and R ² are C═O in the formula (1). 5 to 8 membered ring is formed.
R ¹⁰³ and R ^{104 in} the general formula (2) represent an aromatic group or a heteroaromatic group. R ¹⁰³ and R ¹⁰⁴ may be bonded directly or via a linking group to form a 6-8 membered ring containing —C (═O) C (═O) — in the formula (2).
A plurality of compounds represented by general formula (1) or (2) may be combined to form a multimer. )

  The electrolyte solution for a non-aqueous secondary battery of the present invention is a secondary battery equipped with the “initial capacity” indicating initial discharge performance, “cycle characteristics” indicating deterioration resistance during use, and in a charged state. Exhibits excellent performance in all of the “charge storage stability” that indicates deterioration resistance when held for a long period of time.

It is sectional drawing which shows typically the structure of the lithium ion secondary battery which concerns on preferable embodiment of this invention. It is sectional drawing which shows the specific structure of the lithium ion secondary battery which concerns on preferable embodiment of this invention. It is the voltammogram measured in the reference example (compound used for an Example). It is the voltammogram measured in the reference example (compound used for a comparative example).

    Hereinafter, embodiments of the present invention will be described in detail. However, the configuration of the present invention is not construed as being limited by the contents.

The electrolyte solution for non-aqueous secondary batteries of the present invention (hereinafter also referred to as “electrolyte solution”) contains an anion polymerizable monomer and a specific polymerization initiator precursor in an organic solvent. Hereinafter, the preferable embodiment will be described.
[First additive: anionic polymerizable monomer]
As long as it is known as an anion polymerizable monomer, it is included in the range applicable to the present invention, and is not particularly limited. Among them, in particular, the following general formulas (3-a) to (3-d) It is preferable to use a compound having a structure represented by These compounds may be used alone or in any combination of two or more.

・ R ³
In the above formula (3-a), R ³ represents a hydrogen atom or an alkyl group. A preferable alkyl group as R ³ is an alkyl group having 1 to 10 carbon atoms (methyl, ethyl, hexyl, cyclohexyl, etc.), and R ³ is more preferably a hydrogen atom.

・ R ⁴
R ^{4 in the} formula (3-a) represents an aromatic group, a heterocyclic group, a nitrile group, an alkoxy group, or an acyloxy group. The aromatic group of R ⁴ is preferably a 2π-aromatic group having 6 to 10 carbon atoms (phenyl, naphthyl, etc.), and the heterocyclic group is a heteroaromatic group having 4 to 9 carbon atoms (furyl, pyridyl, pyrazyl, Pyrimidyl, quinolyl, etc.) are preferable, alkoxy groups having 1 to 10 carbon atoms (methoxy, ethoxy, butoxy, etc.) are preferable, and acyloxy groups having 1 to 10 carbon atoms (acetoxy group, hexanoyloxy). Group) and the like, and R ⁴ in formula (3-a) is more preferably a phenyl group. In the present specification, “kara” is used in the same meaning as “to”, and includes a numerical value or a number defined before and after that.

・ R ⁵
R ^{5 in} Formula (3-b) represents hydrogen, an alkyl group, or a cyano group, and a preferable alkyl group is an alkyl group having 1 to 10 carbon atoms (methyl, ethyl, hexyl, cyclohexyl, etc.), hydrogen or More preferred is a methyl group.

・ R ⁶
R ^{6 in the} formula (3-b) represents an alkyl group or an alkoxy group, and more preferably an alkoxy group. That is, the formula (3-b) is preferably an acrylic compound, and more preferably an acrylic ester, a methacrylic ester, or a cyanoacrylic ester. In this case, the alkoxy group corresponding to the alcohol part of the ester is preferably an alkoxy group having 1 to 10 carbon atoms (methoxy, ethoxy, butoxy, etc.), more preferably a methoxy group or an ethoxy group.

・ R ⁷ , R ⁸
R ⁷ and R ^{8 in the} formula (3-c) represent hydrogen, an alkyl group, or an aromatic group. It is preferred that R ⁷ and R ⁸ are hydrogen, or R ⁷ is hydrogen and R ⁸ is an aromatic group. A preferable aromatic group in this case is an aromatic group having 6 to 10 carbon atoms (such as phenyl or naphthyl).

・ X, Y, Z
X, Y, and Z in formula (3-c) are each independently -O-, -S-,-(C = O)-, -C (= S)-, -N (R)-, -S. (O) - and -SO ₂ - represents a divalent linking group selected from, X and Y are -O-, Z is - (C = O) - and that, namely, vinylene compounds are preferred carbonate . R represents an alkyl group or an aromatic group. The preferred alkyl group has the same meaning as R ^3, and the preferred aromatic group has the same meaning as R ⁴ .

・ R ⁹
R ^{9 in the} formula (3-d) represents a hydrogen atom or an alkyl group, preferably a hydrogen atom or an alkyl group having 1 to 10 carbon atoms (methyl, ethyl, hexyl, cyclohexyl, etc.), and preferably a hydrogen atom or a methyl group. More preferred.

The above substituents R ³ to R ⁹ may further contain another substituent T.
Examples of the substituent T include the following.
An alkyl group (preferably an alkyl group having 1 to 20 carbon atoms, such as methyl, ethyl, isopropyl, t-butyl, pentyl, heptyl, 1-ethylpentyl, benzyl, 2-ethoxyethyl, 1-carboxymethyl, etc.); alkenyl A group (preferably an alkenyl group having 2 to 20 carbon atoms such as vinyl, allyl, oleyl and the like); an alkynyl group (preferably an alkynyl group having 2 to 20 carbon atoms such as ethynyl, butadiynyl, phenylethynyl and the like); A cycloalkyl group (preferably a cycloalkyl group having 3 to 20 carbon atoms such as cyclopropyl, cyclopentyl, cyclohexyl, 4-methylcyclohexyl, etc.); an aryl group (preferably an aryl group having 6 to 26 carbon atoms such as Phenyl, 1-naphthyl, 4-methoxyphenyl, -Chlorophenyl, 3-methylphenyl and the like; a heterocyclic group (preferably a heterocyclic group having 2 to 20 carbon atoms, such as 2-pyridyl, 4-pyridyl, 2-imidazolyl, 2-benzoimidazolyl, 2-thiazolyl, 2 -Oxazolyl etc.); alkoxy group (preferably alkoxy group having 1 to 20 carbon atoms such as methoxy, ethoxy, isopropyloxy, benzyloxy etc.); aryloxy group (preferably aryloxy group having 6 to 26 carbon atoms) For example, phenoxy, 1-naphthyloxy, 3-methylphenoxy, 4-methoxyphenoxy and the like; alkoxycarbonyl groups (preferably alkoxycarbonyl groups having 2 to 20 carbon atoms, such as ethoxycarbonyl, 2-ethylhexyloxycarbonyl and the like) ); Amino group (preferably carbon) An amino group having 0 to 20 children, such as amino, N, N-dimethylamino, N, N-diethylamino, N-ethylamino, anilino, etc .; a sulfonamide group (preferably a sulfonamide having 0 to 20 carbon atoms) A group such as N, N-dimethylsulfonamide, N-phenylsulfonamide, etc .; an acyl group (preferably an acyl group having 2 to 20 carbon atoms such as acetyl, benzoyl, etc.); an acyloxy group (preferably a carbon atom) An acyloxy group having 1 to 20 carbon atoms, such as acetyloxy, benzoyloxy, etc .; a carbamoyl group (preferably a carbamoyl group having 1 to 20 carbon atoms, such as N, N-dimethylcarbamoyl, N-phenylcarbamoyl, etc.); A group (preferably an acylamino group having 1 to 20 carbon atoms, such as acetylamino, Benzoylamino, etc.]; cyano group, halogen atom (eg fluorine atom, chlorine atom, bromine atom, iodine atom, etc.), more preferably alkyl group, alkenyl group, aryl group, heterocyclic group, alkoxy group, aryloxy group An alkoxycarbonyl group, an amino group, an acylamino group, a cyano group or a halogen atom, particularly preferably an alkyl group, an alkenyl group, a heterocyclic group, an alkoxy group, an alkoxycarbonyl group, an amino group, an acylamino group or a cyano group. .

  When a compound or a substituent includes an alkyl group, an alkenyl group, etc., these may be linear or branched, and may be substituted or unsubstituted. When an aryl group, a heterocyclic group, or the like is included, they may be monocyclic or condensed, and may be substituted or unsubstituted.

  In addition, in this specification, it uses for the meaning containing the salt, a complex, and its ion besides the said compound itself about the display of a compound. Moreover, it is the meaning including the derivative | guide_body which changed the predetermined part in the range with the desired effect. In addition, in the present specification, a substituent or a linking group for which substitution / non-substitution is not specified clearly means that the group may have an arbitrary substituent. This is also synonymous for compounds that do not specify substitution / non-substitution. Examples of the preferred substituent include the substituent T.

  Examples of the compounds represented by the general formulas (3-a) to (3-d) include the following. However, the present invention is not construed as being limited by these examples.

  When the amount of the first additive (anionic polymerizable monomer) is small, the effect of improving the cycle characteristics is small, and when the amount is too large, the internal resistance of the battery increases, so the initial characteristics of the battery Is damaged. The concentration range of the first additive is preferably in the range of 0.001M to 0.1M (mol / l), and more preferably in the range of 0.005M to 0.05M.

[Second additive: polymerization initiator precursor]
The polymerization initiator precursor as the second additive is (A) a compound represented by the following general formula (1 ′), (B) a compound represented by the following general formula (2), or (C) Any of the compounds reduced at a potential of 0 to 1.9 V (vs. lithium) on the negative electrode. Whether or not the polymerization initiator precursor belongs to the compound (C) can be determined by whether or not the polymerization initiator precursor exhibits a reduction current peak potential. Specific measurement methods and results thereof will be described later in the Examples. Typically, whether or not a current peak of 0.1 mA / cm ² or more in absolute value is shown in a voltammogram when a potential in the above range is swept. Whether or not it can be reduced can be evaluated. This peak may be broad or have a shoulder, and can be evaluated and judged within the range where the effects of the present invention are exhibited. Alternatively, the peak may be evaluated by subtracting the baseline of the chart.

(R ¹⁰¹ and R ¹⁰² in the general formula (1 ′) represent an aromatic group or a heteroaromatic group. R ¹⁰¹ and R ¹⁰² are bonded directly or via a linking group, and the C in the formula (1 ′) Forms a 5- to 8-membered ring containing ═O.
R ¹⁰³ and R ^{104 in} the general formula (2) represent an aromatic group or a heteroaromatic group. R ¹⁰³ and R ¹⁰⁴ may be bonded directly or via a linking group to form a 6-8 membered ring containing —C (═O) C (═O) — in the formula (2).
A plurality of compounds represented by the general formula (1 ′) or (2) may be combined to form a multimer. )

  Moreover, a preferable compound in the said (C) compound is a compound shown by following General formula (1).

R ¹ and R ^{2 in} the general formula (1) represent an aromatic group or a heteroaromatic group (unsaturated heterocyclic group), and preferably a phenyl group, a naphthyl group, or a pyridyl group. R ¹ and R ² may be bonded directly or via a linking group to form a 5- to 8-membered ring containing C═O in the formula (1). Note that a plurality of compounds represented by the general formula (1) may be combined to form a multimer. In the present invention, R ¹ and R ² are preferably bonded directly or via a linking group to form a 5- to 8-membered ring containing C═O.

  The polymerization initiator precursor is more preferably a compound represented by the following general formula (1) or (2).

（一般式（１）のＲ^１及びＲ^２は、芳香族基または複素芳香族基を表す。Ｒ^１とＲ^２は、直接あるいは連結基を介して結合し、式（１）のＣ＝Ｏを含む５〜８員環を形成してもよい。
ただし、式（１）で表される化合物が、負極上において電位１．９Ｖ超（対リチウム換算）で還元される化合物である場合は、Ｒ^１とＲ^２は式（１）のＣ＝Ｏを含む５〜８員環を形成する。
一般式（２）のＲ^１０３及びＲ^１０４は、芳香族基または複素芳香族基を表す。Ｒ^１０３とＲ^１０４は、直接あるいは連結基を介して結合し、式（２）の−Ｃ（＝Ｏ）Ｃ（＝Ｏ）−を含む６〜８員環を形成してもよい。
一般式（１）または（２）で表される化合物は、複数のものが結合して多量体を構成していてもよい。）

(R ¹ and R ^{2 in} the general formula (1) represent an aromatic group or a heteroaromatic group. R ¹ and R ² are bonded directly or via a linking group, and C = O in the formula (1) A 5- to 8-membered ring containing
However, when the compound represented by the formula (1) is a compound that is reduced on the negative electrode at a potential exceeding 1.9 V (vs. lithium), R ¹ and R ² are C═O in the formula (1). 5 to 8 membered ring is formed.
R ¹⁰³ and R ^{104 in} the general formula (2) represent an aromatic group or a heteroaromatic group. R ¹⁰³ and R ¹⁰⁴ may be bonded directly or via a linking group to form a 6-8 membered ring containing —C (═O) C (═O) — in the formula (2).
A plurality of compounds represented by general formula (1) or (2) may be combined to form a multimer. )

  The polymerization initiator precursor is a 9-fluorenone compound, anthrone compound, xanthone compound, dibenzosuberone compound, dibenzosuberone compound, anthraquinone compound, biantronyl compound, biantron compound, substituted benzophenone compound, dibenzoyl compound, and derivatives thereof It is preferably at least one selected from the group consisting of: In terms of chemical structural formula, it is more preferably a compound having a skeleton represented by the following formulas (1-1) to (1-27) (in the present invention, the chemical structure is referred to as the skeleton having a predetermined chemical structure). In addition to a compound having a structure, it is used to mean a compound having the structure as a mother nucleus. The term “compound” is as defined above.) In other words, more preferable polymerization initiator precursors are 9-fluorenone skeleton (1-1), anthrone skeleton (1-2), xanthone skeleton (1-3), dibenzosuberone skeleton (1-4), dibenzo Carbon having a structure of suberone skeleton (1-5), anthraquinone skeleton (1-6), biantronyl skeleton (1-8), biantron skeleton (1-9), substituted benzophenone skeleton, and aromatic ring carbon A structure in which one or two of the elements are changed to nitrogen elements (1-7, 1-13 to 1-23, etc.), or a polybenzene aromatic ring (for example, a naphthalene ring) by condensation of four carbons to a benzene ring It has a formed structure (1-10, 1-11, etc.) and a dibenzoyl skeleton (1-25, 1-26, 1-27). In addition, these skeletons may have a substituent, and preferred substituents include the substituent T. More preferred substituents are a methoxy group, a cyano group, a methanesulfonyl group, an acetyl group, and a fluorine atom.

  The following can be illustrated as said polymerization initiator precursor. However, the present invention is not construed as being limited by these examples.

  The compounds having the skeletons of formulas (1-1) to (1-27) may form a multimer of dimers or more, directly or via a linking group. As the polymerization initiator precursor used in the present invention, among the compounds having the skeleton, the formulas (1-1) to (1-12), (1-15) to (1-23), (1 It is preferably at least one selected from the group consisting of the compounds represented by -26) and (1-27) or derivatives thereof, (1-1), (1-2), (1- 3), (1-4), (1-6), a compound having a skeleton of (1-26) is more preferable, and a compound having a skeleton of (1-1) is particularly preferable.

  In the polymerization initiator precursor, the compound (A) and the compound (B) may satisfy the requirements for the compound (C). That is, the compound (A) and the compound (B) may be compounds reduced on the negative electrode at a potential of 0 to 1.9 V (vs. lithium). Moreover, the said polymerization initiator precursor may be comprised by 2 or more types selected from the group which consists of said (A) compound, said (B) compound, and said (C) compound.

  When the amount of the second additive (polymerization initiator precursor) added is small, the effect of improving the cycle characteristics is small, and when the amount added is too large, the internal resistance of the battery increases, so Properties are impaired. The concentration range of the second additive is preferably in the range of 0.001M to 0.05M (mol / l), more preferably in the range of 0.005M to 0.05M.

  A reaction mechanism according to a preferred embodiment of the present invention will be described using Scheme A below. With the mechanism described in JP-A-11-97059 (Patent Document 7), SEI cannot be formed unless overcharging occurs. On the other hand, in the present invention, the polymerization initiator precursor (9-fluorenone in this example) has an appropriate reduction potential. Therefore, by combining an electrode reaction active precursor, the reduced product becomes an anionic polymerization initiator and acts on the anion polymerizable monomer. Thereby, SEI which consists of a polymer of an anion-polymerizable monomer, etc. efficiently can be formed at normal operating potential. As a result, according to the present invention, a desired excellent effect is exhibited even at a normal operating potential.

(Organic solvent)
Examples of the organic solvent used in the present invention include ethylene carbonate, propylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, methyl propyl carbonate, γ-butyrolactone, γ-valerolactone, 1,2-dimethoxyethane. , Tetrahydrofuran, 2-methyltetrahydrofuran, tetrahydropyran, 1,3-dioxolane, 4-methyl-1,3-dioxolane, 1,3-dioxane, 1,4-dioxane, methyl acetate, ethyl acetate, methyl propionate, propion Ethyl acid, methyl butyrate, methyl isobutyrate, methyl trimethyl acetate, ethyl trimethyl acetate, acetonitrile, glutaronitrile, adiponitrile, methoxyacetonitrile, 3-methoxypropionitrile, N, N-dimethylformamide, N-methylpi Examples include loridinone, N-methyloxazolidinone, N, N′-dimethylimidazolidinone, nitromethane, nitroethane, sulfolane, trimethyl phosphate, dimethyl sulfoxide, and dimethyl sulfoxide phosphoric acid. These may be used alone or in combination of two or more. Among them, at least one member selected from the group consisting of ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate is preferable. Particularly, a high viscosity (high dielectric constant) solvent such as ethylene carbonate or propylene carbonate (for example, ratio A combination of a dielectric constant ε ≧ 30) and a low viscosity solvent such as dimethyl carbonate, ethyl methyl carbonate, or diethyl carbonate (for example, viscosity ≦ 1 mPa · s) is more preferable. This is because the dissociation property of the electrolyte salt and the ion mobility are improved.
However, the organic solvent (nonaqueous solvent) used in the present invention is not limited to the above examples.

  Moreover, the organic solvent may contain the cyclic carbonate which has an unsaturated bond. This is because the chemical stability of the electrolytic solution is further improved. Examples of the cyclic carbonate having an unsaturated bond include at least one selected from the group consisting of vinylene carbonate compounds, vinyl ethylene carbonate compounds, and methylene ethylene carbonate compounds.

  Examples of the vinylene carbonate compound include vinylene carbonate (1,3-dioxol-2-one), methyl vinylene carbonate (4-methyl-1,3-dioxol-2-one), and ethyl vinylene carbonate (4-ethyl- 1,3-dioxol-2-one), 4,5-dimethyl-1,3-dioxol-2-one, 4,5-diethyl-1,3-dioxol-2-one, 4-fluoro-1,3 -Dioxol-2-one or 4-trifluoromethyl-1,3-dioxol-2-one and the like.

  Examples of the vinyl carbonate-based compound include vinyl ethylene carbonate (4-vinyl-1,3-dioxolan-2-one), 4-methyl-4-vinyl-1,3-dioxolan-2-one, and 4-ethyl. -4-vinyl-1,3-dioxolan-2-one, 4-n-propyl-4-vinyl-1,3-dioxolan-2-one, 5-methyl-4-vinyl-1,3-dioxolane-2 -One, 4,4-divinyl-1,3-dioxolan-2-one, 4,5-divinyl-1,3-dioxolan-2-one and the like.

  Examples of the methylene ethylene carbonate compound include 4-methylene-1,3-dioxolan-2-one, 4,4-dimethyl-5-methylene-1,3-dioxolan-2-one, and 4,4-diethyl-5-one. And methylene-1,3-dioxolan-2-one.

  These may be used alone or in combination of two or more. Among these, vinylene carbonate is preferable. This is because a high effect can be obtained.

(Group 1 or Group 2 ions, etc.)
The metal ions belonging to Group 1 or Group 2 of the periodic table contained in the electrolytic solution of the present invention or salts thereof are appropriately selected depending on the intended use of the electrolytic solution, for example, lithium salts, potassium salts, sodium salts, A calcium salt, a magnesium salt, etc. are mentioned, When using for a secondary battery etc., lithium salt is preferable from an output viewpoint. When the electrolytic solution of the present invention is used as an electrolyte of a non-aqueous electrolytic solution for a lithium secondary battery, a lithium salt may be selected as a metal ion salt. The lithium salt is not particularly limited as long as it is a lithium salt usually used for an electrolyte of a non-aqueous electrolyte solution for a lithium secondary battery. For example, those described below are preferable.

(L-1) Inorganic lithium salt: inorganic fluoride salt such as LiPF ₆ , LiBF ₄ , LiAsF ₆ , LiSbF ₆ ; perhalogenate such as LiClO ₄ , LiBRO ₄ , LiIO ₄ ; inorganic chloride salt such as LiAlCl ₄ etc.

(L-2) Fluorine-containing organic lithium salt: Perfluoroalkane sulfonate such as LiCF ₃ SO ₃ ; LiN (CF ₃ SO ₂ ) ₂ , LiN (CF ₃ CF ₂ SO ₂ ) ₂ , LiN (FSO ₂ ) ₂ , Perfluoroalkanesulfonylimide salts such as LiN (CF ₃ SO ₂ ) (C ₄ F ₉ SO ₂ ); perfluoroalkanesulfonylmethide salts such as LiC (CF ₃ SO ₂ ) ₃ ; Li [PF ₅ (CF ₂ CF ₂ CF ₃ )], Li [PF ₄ (CF ₂ CF ₂ CF ₃ ) ₂ ], Li [PF ₃ (CF ₂ CF ₂ CF ₃ ) ₃ ], Li [PF ₅ (CF ₂ CF ₂ CF ₂ CF _{3 )], Li [PF 4 (} CF 2 CF 2 CF 2 CF 3) 2], Li [PF 3 (CF 2 CF 2 CF 2 CF 3) 3] fluoroalkyl fluoride such as potash Acid salts, and the like.

  (L-3) Oxalatoborate salt: lithium bis (oxalato) borate, lithium difluorooxalatoborate and the like.

Among these, LiPF ₆ , LiBF ₄ , LiAsF ₆ , LiSbF ₆ , LiClO ₄ , Li (Rf ¹ SO ₃ ), LiN (Rf ¹ SO ₂ ) ₂ , LiN (FSO ₂ ) ₂ , and LiN (Rf ¹ SO ₂ ) (Rf ² SO ₂ ) ₂ is preferred, such as LiPF ₆ , LiBF ₄ , LiN (Rf ¹ SO ₂ ) ₂ , LiN (FSO ₂ ) ₂ , and LiN (Rf ¹ SO ₂ ) (Rf ² SO ₂ ) ₂ The lithium imide salt is more preferable. Here, Rf ^{1 and} Rf ² each represent a perfluoroalkyl group.
In addition, the lithium salt used for electrolyte solution may be used individually by 1 type, or may combine 2 or more types arbitrarily.
The content of the metal ions belonging to Group 1 or Group 2 of the periodic table or the metal salt thereof in the electrolytic solution is added in an amount so as to obtain a preferable salt concentration described below in the method for preparing the electrolytic solution. The salt concentration is appropriately selected depending on the intended use of the electrolytic solution, but is generally 10% to 50% by mass, more preferably 15% to 30% by mass, based on the total mass of the electrolytic solution. In addition, when evaluating as an ion density | concentration, what is necessary is just to calculate by salt conversion with the metal applied suitably.

[Method for preparing electrolytic solution]
Next, a typical method for preparing the electrolytic solution of the present invention will be described with reference to an example in which a lithium salt is used as a metal ion salt.
The electrolytic solution of the present invention is prepared by dissolving the anionic polymerizable monomer, the polymerization initiator precursor, a lithium salt, and various additives that are optionally added in the non-aqueous solvent.

  In the present invention, “non-water” means that water is not substantially contained, and a trace amount of water may be contained as long as the effects of the invention are not hindered. In view of obtaining good characteristics, the water content is preferably 200 ppm or less, and more preferably 100 ppm or less. Although there is no particular lower limit, it is practical that it is 10 ppm or more considering inevitable mixing.

(Composition of electrolyte)
The lithium salt concentration in the prepared electrolyte solution has an appropriate concentration range for showing high ionic conductivity because the viscosity of the electrolyte solution increases as the concentration increases. A preferable concentration range is 10% by mass to 50% by mass, and more preferably 15% by mass to 30% by mass, based on the total mass of the electrolytic solution. Although the viscosity (25 degreeC) of the electrolyte solution of this invention is not specifically limited, It is preferable that it is 10-0.1 mPa * s, and it is more preferable that it is 5-0.5 mPa * s.

(kit)
The electrolytic solution of the present invention may be a kit composed of a plurality of liquids or powders. For example, the first agent (first liquid) is composed of a metal salt and an organic solvent, the second agent (second liquid) is composed of the anionic polymerizable monomer and the organic solvent, and the two liquids are mixed before use. Then, it may be in the form of liquid preparation. At this time, in the kit of the present invention, a polymerization initiator precursor is contained in the first agent, the second agent, and / or other agent. By doing in this way, interaction with the above-mentioned anion polymerizable monomer and the above-mentioned polymerization initiator precursor can be obtained effectively. In addition, it is preferable that content of said each component becomes said range after mixing.

  The polymerization initiator precursor that can be used in the kit of the present invention includes (A) a compound represented by the following general formula (1 ′), (B) a compound represented by the following general formula (2), or ( C) Any of compounds reduced at a potential of 0 to 1.9 V (vs. lithium) on the negative electrode.

（一般式（１’）のＲ^１０１及びＲ^１０２は、芳香族基または複素芳香族基を表す。Ｒ^１０１とＲ^１０２は、直接あるいは連結基を介して結合し、式（１’）のＣ＝Ｏを含む５〜８員環を形成する。
一般式（２）のＲ^１０３及びＲ^１０４は、芳香族基または複素芳香族基を表す。Ｒ^１０３とＲ^１０４は、直接あるいは連結基を介して結合し、式（２）の−Ｃ（＝Ｏ）Ｃ（＝Ｏ）−を含む６〜８員環を形成してもよい。
一般式（１’）または（２）で表される化合物は、複数が結合して多量体を構成していてもよい。
前記（Ｃ）化合物は、下記一般式（１）で表される化合物であることが好ましい。

(R ¹⁰¹ and R ¹⁰² in the general formula (1 ′) represent an aromatic group or a heteroaromatic group. R ¹⁰¹ and R ¹⁰² are bonded directly or via a linking group, and the C in the formula (1 ′) Forms a 5- to 8-membered ring containing ═O.
R ¹⁰³ and R ^{104 in} the general formula (2) represent an aromatic group or a heteroaromatic group. R ¹⁰³ and R ¹⁰⁴ may be bonded directly or via a linking group to form a 6-8 membered ring containing —C (═O) C (═O) — in the formula (2).
A plurality of the compounds represented by the general formula (1 ′) or (2) may be combined to form a multimer.
The compound (C) is preferably a compound represented by the following general formula (1).

（一般式（１）のＲ^１及びＲ^２は、芳香族基または複素芳香族基を表す。Ｒ^１とＲ^２は、直接あるいは連結基を介して結合し、式（１）のＣ＝Ｏを含む５〜８員環を形成してもよい。
一般式（１）で表される化合物は、複数のものが結合して多量体を構成していてもよい。）

(R ¹ and R ^{2 in} the general formula (1) represent an aromatic group or a heteroaromatic group. R ¹ and R ² are bonded directly or via a linking group, and C = O in the formula (1) A 5- to 8-membered ring containing
A plurality of compounds represented by the general formula (1) may be combined to form a multimer. )

  The polymerization initiator precursor contained in at least one of the first agent, the second agent, and the other agent is any one of the compounds represented by the general formula (1) or (2). It is more preferable.

（一般式（１）のＲ^１及びＲ^２は、芳香族基または複素芳香族基を表す。Ｒ^１とＲ^２は、直接あるいは連結基を介して結合し、式（１）のＣ＝Ｏを含む５〜８員環を形成してもよい。
ただし、式（１）で表される化合物が、負極上において電位１．９Ｖ超（対リチウム換算）で還元される化合物である場合は、Ｒ^１とＲ^２は式（１）のＣ＝Ｏを含む５〜８員環を形成する。
一般式（２）のＲ^１０３及びＲ^１０４は、芳香族基または複素芳香族基を表す。Ｒ^１０３とＲ^１０４は、直接あるいは連結基を介して結合し、式（２）の−Ｃ（＝Ｏ）Ｃ（＝Ｏ）−を含む６〜８員環を形成してもよい。
一般式（１）または（２）で表される化合物は、複数のものが結合して多量体を構成していてもよい。）

(R ¹ and R ^{2 in} the general formula (1) represent an aromatic group or a heteroaromatic group. R ¹ and R ² are bonded directly or via a linking group, and C = O in the formula (1) A 5- to 8-membered ring containing
However, when the compound represented by the formula (1) is a compound that is reduced on the negative electrode at a potential exceeding 1.9 V (vs. lithium), R ¹ and R ² are C═O in the formula (1). 5 to 8 membered ring is formed.
R ¹⁰³ and R ^{104 in} the general formula (2) represent an aromatic group or a heteroaromatic group. R ¹⁰³ and R ¹⁰⁴ may be bonded directly or via a linking group to form a 6-8 membered ring containing —C (═O) C (═O) — in the formula (2).
A plurality of compounds represented by general formula (1) or (2) may be combined to form a multimer. )

[Secondary battery]
As a preferred embodiment of the present invention, a lithium ion secondary battery will be described with reference to FIG. The lithium ion secondary battery 10 of this embodiment includes the electrolyte solution 5 for a non-aqueous secondary battery of the present invention and a positive electrode C capable of inserting and releasing lithium ions (a positive electrode current collector 1 and a positive electrode active material layer 2). And a negative electrode A (negative electrode current collector 3, negative electrode active material layer 4) capable of inserting and releasing lithium ions or dissolving and depositing lithium ions. In addition to these essential members, considering the purpose of use of the battery, the shape of the potential, etc., a separator 9 disposed between the positive electrode and the negative electrode, a current collecting terminal (not shown), an outer case, etc. (Not shown). If necessary, a protective element may be attached to at least one of the inside of the battery and the outside of the battery. By adopting such a structure, the exchange α of lithium ions occurs in the electrolytic solution 5 and the charge α can be performed, and the exchange β can occur and the discharge β can be performed. Further, operation or power storage can be performed via the circuit wiring 7 and the operation mechanism 6.
For the lithium secondary battery of the present invention, as described above, the anion polymerizable monomer and the polymerization initiator precursor effectively act to form good SEI on the negative electrode surface 4a or the positive electrode surface 2a, and the initial battery capacity It is considered that the improvement of the cycle characteristics and the charge storage stability were maintained. Note that FIG. 1 is schematically illustrated for the sake of explanation, and the present invention is not construed as being limited by the configuration shown in FIG.

(Battery shape)
The battery shape to which the lithium secondary battery of the present embodiment is applied is not particularly limited, and examples thereof include a bottomed cylindrical shape, a bottomed square shape, a thin shape, a sheet shape, and a paper shape. Any of these may be used. Further, in consideration of the shape of the system to be incorporated and the shape of the device to be incorporated, a different shape such as a horseshoe shape or a comb shape may be used. Among these, from the viewpoint of efficiently releasing the heat inside the battery to the outside, a rectangular shape such as a bottomed rectangular shape or a thin shape having at least one surface that is relatively flat and has a large area is preferable.

  In a battery having a bottomed cylindrical shape, since the outer surface area with respect to the power generating element to be filled becomes small, it is preferable to design so that Joule heat generated by the internal resistance at the time of charging or discharging can be efficiently released to the outside. Moreover, it is preferable to design so that the filling ratio of the substance having high thermal conductivity is increased and the temperature distribution inside is reduced.

In the bottomed rectangular shape, the area of the largest surface (maximum surface) S (the product of the width and height of the outer dimensions excluding the terminal portion, unit cm ² ) and the thickness T (unit cm) of the battery outer shape ) And the ratio 2S / T is preferably 100 or more, and more preferably 200 or more. By increasing the maximum surface S, characteristics such as cycle performance and high-temperature storage can be improved even for high-power and large-capacity batteries, and heat dissipation efficiency during abnormal heat generation can be improved. And a dangerous state of “burst” can be suppressed.

(Members constituting the battery)
The lithium secondary battery of this embodiment includes an electrolytic solution 5, an electrode mixture C of positive and negative electrodes C and A, and a basic member 9 of a separator. Hereinafter, each of these members will be described. The lithium secondary battery of the present invention includes at least the electrolyte solution for a non-aqueous secondary battery of the present invention as an electrolytic solution.
(Electrolyte)
The electrolytic solution used in the lithium secondary battery of the present embodiment is prepared by the method described above, the anion polymerizable monomer, the polymerization initiator precursor, a nonaqueous solvent, and a lithium salt as an electrolyte salt. It is preferable to contain as a main component the electrolyte solution for non-aqueous secondary batteries of this invention containing at least. That is, the electrolytic solution 5 is an electrolytic solution for a nonaqueous secondary battery containing at least the anion polymerizable monomer, the polymerization initiator precursor, the nonaqueous solvent, and a lithium salt as an electrolyte salt. Is preferred. As the electrolyte salt used in the electrolyte solution for non-aqueous secondary battery, the salt of metal ion belonging to Group 1 or Group 2 of the above periodic table, that is, the electrolyte solution for non-aqueous secondary battery of the present invention. Those described in detail in the embodiment can be used. Moreover, what was described in detail in the aspect of the electrolyte solution for non-aqueous secondary batteries of the said this invention can be similarly used for the non-aqueous solvent used for the lithium secondary battery of this embodiment. Furthermore, other additives can be added to further improve the performance.

  In the electrolytic solution according to the present invention, various additives can be used depending on the purpose as long as the effects of the present invention are not impaired in order to improve battery performance. As such an additive, a functional additive such as an overcharge inhibitor, a negative electrode film forming agent, a positive electrode protective agent, or the like may be used.

  Moreover, the combined use of a negative electrode film forming agent and a positive electrode protective agent, or the combined use of an overcharge inhibitor, a negative electrode film forming agent, and a positive electrode protective agent is particularly preferable.

  The content ratio of these functional additives in the non-aqueous electrolyte solution is not particularly limited, but is preferably 0.01% by mass or more, particularly preferably 0.1% by mass or more, respectively, with respect to the entire non-aqueous electrolyte solution. More preferably, it is 0.2% by mass or more, and the upper limit is preferably 5% by mass or less, particularly preferably 3% by mass or less, and further preferably 2% by mass or less. By adding these compounds, it is possible to suppress rupture / ignition of the battery at the time of abnormality due to overcharge, and to improve the capacity maintenance characteristic and cycle characteristic after high-temperature storage.

(Electrode mixture)
The electrode mixture is obtained by applying a dispersion of an active material and a conductive material, a binder, a filler, etc. on a current collector (electrode base material). In a lithium secondary battery, the active material is a positive electrode active material. And a negative electrode mixture in which the active material is a negative electrode active material. Next, the positive electrode active material, the negative electrode active material, the conductive material, the binder, the filler, and the current collector that constitute the electrode mixture will be described.
(Positive electrode active material)
A particulate positive electrode active substance may be used in the electrolyte solution for a non-aqueous secondary battery of the present invention. As the positive electrode active material used in the present invention, a transition metal oxide capable of reversibly inserting and releasing lithium ions can be used, but a lithium-containing transition metal oxide is preferably used. In the present invention, preferred examples of the lithium-containing transition metal oxide preferably used as the positive electrode active material include oxides containing lithium, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Mo, and W. It is done. Alkali metals other than lithium (elements of Group 1 (Ia) and Group 2 (IIa) of the periodic table) and / or Al, Ga, In, Ge, Sn, Pb, Sb, Bi, Si, P , B, etc. may be mixed. The mixing amount is preferably 0 to 30 mol% with respect to the transition metal.

  Among the lithium-containing transition metal oxides preferably used as the positive electrode active material, a lithium compound / transition metal compound (wherein the transition metal is selected from Ti, V, Cr, Mn, Fe, Co, Ni, Mo, W) It is more preferable that the mixture is synthesized so that the total molar ratio of the compound is 0.3 to 2.2.

Further, among the lithium compounds / transition metal compounds, Li _g M3O ₂ (M3 represents one or more elements selected from Co, Ni, Fe, and Mn. G represents 0 to 1.2. ) Or a material having a spinel structure represented by Li _h M4 ₂ O (M4 represents Mn. H represents 0 to 2). As M3 and M4, Al, Ga, In, Ge, Sn, Pb, Sb, Bi, Si, P, and B may be mixed in addition to the transition metal. The mixing amount is preferably 0 to 30 mol% with respect to the transition metal.

The _Li g M3O material containing _2, among the materials having the spinel structure represented by _{Li h M4 2 O, Li g} CoO 2, Li g NiO 2, Li g MnO 2, Li g Co j Ni 1-j O _{2, Li h Mn 2 O 4} , LiNi j Mn 1-j O 2, LiCo j Ni h Al 1-j-h O 2, LiCo j Ni h Mn 1-j-h O 2, LiMn h Al 2-h O ₄ , LiMn _h Ni _{2 -h} O ₄ (where g represents 0.02 to 1.2, j represents 0.1 to 0.9, and h represents 0 to 2) is particularly preferable. , More preferably _{Li g CoO 2, LiMn 2 O} 4, LiNi 0.85 Co 0.01 Al 0.05 O 2, and is _{LiNi 0.33 Co 0.33 Mn 0.33 O 2} . Of these, an electrode containing Ni is more preferable from the viewpoint of high capacity and high output. Here, the g value and the h value are values before the start of charging / discharging, and are values that increase or decrease due to charging / discharging. In particular,
LiNi _0.5 Mn _0.5 O ₂ , LiNi _0.85 Co _0.01 Al _0.05 O ₂ ,
LiNi _0.33 Co _0.33 Mn _0.33 O ₂ , LiMn _1.8 Al _0.2 O ₄ ,
LiMn _1.5 Ni _0.5 O ₄ and the like.

Examples of the lithium-containing transition metal oxide include lithium-containing transition metal phosphate compounds. Examples of the transition metal of the lithium-containing transition metal phosphate compound include Ti, V, Cr, Mn, Fe, Co, Ni, and Cu. Preferable examples include, for example, iron phosphates such as LiFePO ₄ , Li ₃ Fe ₂ (PO ₄ ) ₃ , LiFeP ₂ O ₇ , cobalt phosphates such as LiCoPO ₄ , and lithium-containing transition metal phosphates. Replacing some of the transition metal atoms that are the main component of the compound with other metals such as Al, Ti, V, Cr, Mn, Fe, Co, Li, Ni, Cu, Zn, Mg, Ga, Zr, Nb, and Si And the like.

In the secondary battery using the nonaqueous electrolytic solution of the present invention, the average particle size of the positive electrode active material used is not particularly limited, but is preferably 0.1 μm to 50 μm. The No particular limitation is imposed on the specific surface area of the positive electrode active material, preferably from 0.01m ² / g~50m ² / g by the BET method. Further, the pH of the supernatant liquid when 5 g of the positive electrode active material is dissolved in 100 ml of distilled water is preferably 7 or more and 12 or less.

  In order to make the positive electrode active substance have a predetermined particle size, a well-known pulverizer or classifier is used. For example, a mortar, a ball mill, a vibration ball mill, a vibration mill, a satellite ball mill, a planetary ball mill, a swirling air flow type jet mill, a sieve, or the like is used. The positive electrode active material obtained by the firing method may be used after being washed with water, an acidic aqueous solution, an alkaline aqueous solution, or an organic solvent.

(Negative electrode active material)
The negative electrode active material used in the electrolyte solution for a non-aqueous secondary battery of the present invention is not particularly limited as long as it can reversibly insert and release lithium ions. Carbonaceous materials, tin oxide, silicon oxide, etc. Metal oxides; metal composite oxides; lithium alloys such as lithium alone and lithium aluminum alloys; metals capable of forming alloys with lithium such as Sn and Si; and the like.
These may be used individually by 1 type, or may use 2 or more types together by arbitrary combinations and a ratio. Of these, carbonaceous materials or lithium composite oxides are preferably used from the viewpoint of safety.
Further, the metal composite oxide is not particularly limited as long as it can occlude and release lithium, but it preferably contains titanium and / or lithium as a constituent component from the viewpoint of high current density charge / discharge characteristics. .

  The carbonaceous material used as the negative electrode active material is a material substantially made of carbon. Examples thereof include carbonaceous materials obtained by baking various synthetic resins such as artificial pitches such as petroleum pitch, natural graphite, and vapor-grown graphite, and PAN-based resins and furfuryl alcohol resins. Further, various carbon fibers such as PAN-based carbon fiber, cellulose-based carbon fiber, pitch-based carbon fiber, vapor-grown carbon fiber, dehydrated PVA-based carbon fiber, lignin carbon fiber, glassy carbon fiber, activated carbon fiber, etc .; mesophase micro Spheres; graphite whiskers; flat graphite and the like.

  These carbonaceous materials can be divided into non-graphitizable carbon materials and graphite-based carbon materials depending on the degree of graphitization. Further, the carbonaceous material preferably has the surface spacing, density, and crystallite size described in JP-A-62-222066, JP-A-2-6856, and 3-45473. The carbonaceous material does not need to be a single material, and a mixture of natural graphite and artificial graphite described in JP-A-5-90844, graphite having a coating layer described in JP-A-6-4516, or the like is used. You can also.

  The metal oxide and metal composite oxide, which are negative electrode active materials used in the lithium secondary battery of the present embodiment, need only contain at least one of them. As the metal oxide and metal complex oxide, amorphous oxide is particularly preferable, and chalcogenide which is a reaction product of a metal element and an element of Group 16 of the periodic table is also preferably used. The term “amorphous” as used herein means an X-ray diffraction method using CuKα rays, which has a broad scattering band having an apex in a region of 20 ° to 40 ° in terms of 2θ value. You may have a line. The strongest intensity of crystalline diffraction lines seen from 2 ° to 40 ° to 70 ° is 100 times the diffraction line intensity at the peak of the broad scattering band seen from 2 ° to 20 °. It is preferable that it is 5 times or less, and it is particularly preferable not to have a crystalline diffraction line.

Among the compound group consisting of the amorphous oxide and the chalcogenide, an amorphous oxide of a metalloid element and a chalcogenide are more preferable, and elements of Groups 13 (IIIB) to 15 (VB) of the periodic table, Particularly preferred are oxides and chalcogenides composed of one kind of Al, Ga, Si, Sn, Ge, Pb, Sb, Bi or a combination of two or more kinds thereof. Specific examples of preferable amorphous oxides and chalcogenides include, for example, Ga ₂ O ₃ , SiO, GeO, SnO, SnO ₂ , PbO, PbO ₂ , Pb ₂ O ₃ , Pb ₂ O ₄ , Pb ₃ O ₄ , Sb ₂ O ₃ , Sb ₂ O ₄ , Sb ₂ O ₅ , Bi ₂ O ₃ , Bi ₂ O ₄ , SnSiO ₃ , GeS, SnS, SnS ₂ , PbS, PbS ₂ , Sb ₂ S ₃ , Sb ₂ S ₅ , such as SnSiS ₃ may preferably be mentioned. Moreover, these may be a complex oxide with lithium oxide, for example, Li ₂ SnO ₂ .

  In the nonaqueous electrolyte secondary battery of the present invention, the average particle size of the negative electrode active material used is preferably 0.1 μm to 60 μm. To obtain a predetermined particle size, a well-known pulverizer or classifier is used. For example, a mortar, a ball mill, a sand mill, a vibrating ball mill, a satellite ball mill, a planetary ball mill, a swirling air flow type jet mill or a sieve is preferably used. When pulverizing, wet pulverization in the presence of water or an organic solvent such as methanol can be performed as necessary. In order to obtain a desired particle size, classification is preferably performed. The classification method is not particularly limited, and a sieve, an air classifier, or the like can be used as necessary. Classification can be used both dry and wet.

  The chemical formula of the compound obtained by the firing method can be calculated from an inductively coupled plasma (ICP) emission spectroscopic analysis method as a measurement method and a mass difference between powders before and after firing as a simple method.

  In the present invention, as the negative electrode active material that can be used in combination with the amorphous oxide negative electrode active material centering on Sn, Si, Ge, a carbon material capable of inserting and extracting lithium ions or lithium metal, lithium, Preferred examples include lithium alloys and metals capable of forming alloys with lithium.

In the present invention, it is preferable to use lithium titanate, more specifically, lithium-titanium oxide (Li [Li _1/3 Ti _5/3 ] O ₄ ) as the active material of the negative electrode. By using this as a negative electrode active material, the formation effect of SEI by the anionic polymerizable monomer and the polymerization initiator precursor is further enhanced, and more excellent battery performance can be exhibited.

(Conductive material)
Any conductive material may be used as long as it is an electron conductive material that does not cause a chemical change in the constructed secondary battery, and any known conductive material can be used. Usually, natural graphite (scale-like graphite, scale-like graphite, earth-like graphite, etc.), artificial graphite, carbon black, acetylene black, ketjen black, carbon fiber and metal powder (copper, nickel, aluminum, silver (Japanese Patent Laid-Open No. Sho 63- 10148,554)), metal fibers or polyphenylene derivatives (described in JP-A-59-20971) can be contained as a single type or a mixture thereof. Among these, the combined use of graphite and acetylene black is particularly preferable. As addition amount of the said electrically conductive material, 1-50 mass% is preferable and 2-30 mass% is more preferable. In the case of carbon or graphite, 2 to 15% by mass is particularly preferable.

(Binder)
In the present invention, it is preferable to use a binder for holding the electrode mixture.
Examples of the binder include polysaccharides, thermoplastic resins, and polymers having rubber elasticity. Among them, for example, starch, carboxymethylcellulose, cellulose, diacetylcellulose, methylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, sodium alginate, Polyacrylic acid, sodium polyacrylate, polyvinyl phenol, polyvinyl methyl ether, polyvinyl alcohol, polyvinyl pyrrolidone, polyacrylonitrile, polyacrylamide, polyhydroxy (meth) acrylate, water-soluble polymers such as styrene-maleic acid copolymer, polyvinyl chloride , Polytetrafluoroethylene, polyvinylidene fluoride, tetrafluoroethylene-hexafluoropropylene copolymer, vinylidene (Meth) acrylic such as fluoride-tetrafluoroethylene-hexafluoropropylene copolymer, polyethylene, polypropylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, polyvinyl acetal resin, methyl methacrylate, 2-ethylhexyl acrylate (Meth) acrylic acid ester copolymer containing acid ester, (meth) acrylic acid ester-acrylonitrile copolymer, polyvinyl ester copolymer containing vinyl ester such as vinyl acetate, styrene-butadiene copolymer, acrylonitrile -Butadiene copolymer, polybutadiene, neoprene rubber, fluoro rubber, polyethylene oxide, polyester polyurethane resin, polyether polyurethane resin, polycarbonate DOO polyurethane resins, polyester resins, phenolic resins, emulsion (latex) or a suspension such as an epoxy resin is preferable, a latex of polyacrylate, carboxymethyl cellulose, polytetrafluoroethylene, polyvinylidene fluoride is more preferable.

  A binder can be used individually by 1 type or in mixture of 2 or more types. When the amount of the binder added is small, the holding power and cohesive force of the electrode mixture are weakened. When the amount of the binder added is too large, the electrode volume increases and the capacity per electrode unit volume or unit mass decreases. For this reason, the addition amount of the binder is preferably 1 to 30% by mass, and more preferably 2 to 10% by mass.

(Filler)
The electrode mixture that can be used in the present invention may contain a filler. As the material for forming the filler, any fibrous material that does not cause a chemical change in the nonaqueous electrolyte secondary battery of the present invention can be used. Usually, fibrous fillers made of materials such as olefin polymers such as polypropylene and polyethylene, glass, and carbon are used. Although the addition amount of a filler is not specifically limited, 0-30 mass% is preferable.

(Current collector)
As the positive / negative current collector, an electronic conductor that does not cause a chemical change in the nonaqueous electrolyte secondary battery of the present invention is used. As the current collector of the positive electrode, in addition to aluminum, stainless steel, nickel, titanium, etc., the surface of aluminum or stainless steel is preferably treated with carbon, nickel, titanium, or silver. Among them, aluminum and aluminum alloys are preferable. More preferred.

  As the negative electrode current collector, copper, stainless steel, nickel, and titanium are preferable, and copper or a copper alloy is more preferable.

As the shape of the current collector, a film sheet shape is usually used, but a net, a punched material, a lath body, a porous body, a foamed body, a molded body of a fiber group, and the like can also be used. The thickness of the current collector is not particularly limited, but is preferably 1 μm to 500 μm. Moreover, it is also preferable that the current collector surface is roughened by surface treatment.
The current collector of the nonaqueous electrolyte secondary battery of the present invention is formed by a member appropriately selected from these materials.

(Separator)
The separator used in the lithium secondary battery according to the present embodiment is a material that has mechanical strength that electrically insulates the positive electrode and the negative electrode, ion permeability, and oxidation / reduction resistance at the contact surface between the positive electrode and the negative electrode. There is no limit. As such a material, a porous polymer material, an inorganic material, an organic-inorganic hybrid material, glass fiber, or the like is used. These separators preferably have a shutdown function for ensuring safety, that is, a function of closing the gap at 80 ° C. or higher to increase resistance and interrupting current, and the closing temperature is 90 ° C. or higher and 180 ° C. or lower. Preferably there is.

  The shape of the hole (gap) of the separator is usually a circle or an ellipse, and the size is 0.05 μm to 30 μm, preferably 0.1 μm to 20 μm. Furthermore, it may be a rod-like or irregular-shaped hole as in the case of making by a stretching method or a phase separation method. The ratio of these gaps, that is, the porosity, is 20% to 90%, preferably 35% to 80%.

  The polymer material may be a single material such as polyethylene or polypropylene, or may be a material using two or more composite materials. What laminated | stacked the 2 or more types of microporous film from which the hole diameter of the hole which a separator has, a porosity, the obstruction | occlusion temperature of a hole (gap), etc. differs is preferable.

  Examples of the inorganic material include oxides such as alumina and silicon dioxide, nitrides such as aluminum nitride and silicon nitride, and sulfates such as barium sulfate and calcium sulfate, and those having a particle shape or fiber shape are used. . As the form, a thin film shape such as a non-woven fabric, a woven fabric, or a microporous film is used. In the thin film shape, those having a pore diameter of 0.01 μm to 1 μm and a thickness of 5 μm to 50 μm are preferably used. In addition to the thin film shape, a separator formed by forming a composite porous layer containing particles of the inorganic material on the surface layer of the positive electrode and / or the negative electrode using a resin binder can be used. For example, alumina particles having a 90% particle diameter of less than 1 μm are formed on both surfaces of the positive electrode as a porous layer using a fluororesin binder.

(Preparation of non-aqueous electrolyte secondary battery)
As described above, the lithium secondary battery of this embodiment can be applied to any shape such as a sheet shape, a square shape, and a cylinder shape. A positive electrode active material or a mixture of negative electrode active materials is mainly used after being applied (coated), dried and compressed on a current collector.

  Hereinafter, with reference to FIG. 2, a configuration and a manufacturing method thereof will be described using the bottomed cylindrical lithium secondary battery 100 as an example. In a battery having a bottomed cylindrical shape, since the outer surface area with respect to the power generating element to be filled becomes small, it is preferable to design so that Joule heat generated by the internal resistance at the time of charging or discharging can be efficiently released to the outside. Moreover, it is preferable to design so that the filling ratio of the substance having high thermal conductivity is increased and the temperature distribution inside is reduced. FIG. 2 shows an example of a bottomed cylindrical lithium secondary battery 100. This battery is a bottomed cylindrical lithium secondary battery 100 in which a positive electrode sheet 14 and a negative electrode sheet 16 overlapped with a separator 12 are wound and accommodated in an outer can 18. 2, 20 is an insulating plate, 22 is a sealing plate, 24 is a positive electrode current collector, 26 is a gasket, 28 is a pressure sensitive valve body, and 30 is a current interrupting element. In addition, although the illustration in the enlarged circle has changed hatching in consideration of visibility, each member corresponds to the whole drawing by reference numerals.

  First, a negative electrode active material and a binder or filler used as desired are dissolved in an organic solvent to prepare a slurry-like or paste-like negative electrode mixture. The obtained negative electrode mixture is uniformly applied over the entire surface of both surfaces of the metal core as a current collector, and then the organic solvent is removed to form a negative electrode mixture layer. Further, the laminate of the current collector and the negative electrode mixture layer is rolled with a roll press or the like to prepare a predetermined thickness to obtain a negative electrode sheet (electrode sheet). At this time, the coating method of each agent, the drying of the coated material, and the method of forming the positive and negative electrodes may be in accordance with conventional methods.

  In this embodiment, a cylindrical battery has been described as an example. However, the present invention is not limited to this, and for example, after the positive and negative electrode sheets manufactured by the above method are overlaid through a separator. Then, it is processed into a sheet-like battery as it is, or after being folded and inserted into a rectangular can (battery can), the can and the electrode sheet are electrically connected, an electrolyte is injected, and a sealing plate May be used to seal the opening to form a prismatic battery.

  In any embodiment, a safety valve can be used as a sealing plate for sealing the opening. In addition to the safety valve, the sealing plate may be provided with various conventionally known safety elements. For example, a fuse, bimetal, PTC element, or the like is preferably used as the overcurrent prevention element.

  In addition to the safety valve, as a countermeasure against the increase in the internal pressure of the battery can, a method of cutting the battery can, a method of cracking the gasket, a method of cracking the sealing plate, or a method of cutting the lead plate can be used. Further, the charger may be provided with a protection circuit incorporating measures against overcharge and overdischarge, or may be connected independently.

  For the can and the lead plate, a metal or alloy having electrical conductivity can be used. For example, metals such as iron, nickel, titanium, chromium, molybdenum, copper, and aluminum, or alloys thereof are preferably used.

  As a method for welding the cap, the can, the sheet, and the lead plate, a known method (eg, direct current or alternating current electric welding, laser welding, ultrasonic welding) can be used. As the sealing agent for sealing, a conventionally known compound or mixture such as asphalt can be used.

[Use of non-aqueous electrolyte secondary battery of the present invention]
The non-aqueous electrolyte secondary battery of the present invention can be applied to various applications because a secondary battery having good cycle characteristics can be produced by adding the anionic polymerizable monomer and the polymerization initiator precursor. The
Although there is no particular limitation on the application mode, for example, when the nonaqueous electrolyte secondary battery of the present invention is mounted on an electronic device, the electronic device may be a notebook computer, pen input personal computer, mobile personal computer, electronic book player, portable Telephone, cordless phone, pager, handy terminal, portable fax, portable copy, portable printer, headphone stereo, video movie, LCD TV, handy cleaner, portable CD, minidisc, electric shaver, transceiver, electronic notebook, calculator, memory Cards, portable tape recorders, radios, backup power supplies, memory cards, etc. Other consumer products include automobiles, electric vehicles, motors, lighting equipment, toys, game equipment, road conditioners, watches, strobes, cameras, medical equipment (such as pacemakers, hearing aids, and shoulder grinders). Furthermore, it can be used for various military use and space use. Moreover, it can also combine with a solar cell.

  Although the metal ion used for charge transport in the nonaqueous electrolyte secondary battery of the present invention is not particularly limited, it is preferable to use a metal ion belonging to Group 1 or Group 2 of the periodic table. Among these, it is preferable to use lithium ions, sodium ions, magnesium ions, calcium ions, aluminum ions, and the like. There are many documents and books such as the patent documents listed at the beginning for general technical matters regarding secondary batteries using lithium ions, which are helpful. In addition, for secondary batteries using sodium ions, Journal of Electrochemical Society; Electrochemical Science and Technology, USA, 1980, Vol. 127, pages 2097-2099, and the like can be referred to. For magnesium ions, see Nature 407, p. 724-727 (2000) and the like can be referred to. For calcium ions, see J.H. Electrochem. Soc. , Vol. 138, 3536 (1991) and the like. In the present invention, it is preferable to apply to a lithium ion secondary battery because of its widespread use, but the other effects also have a desired effect and should not be construed as being limited thereto.

  Examples of the present invention will be described below, but the present invention is not limited to these examples.

<Reference example>
The polymerization initiator precursor shown in Table A was added at a concentration of 0.1 mol / l in an electrolyte solution having a volume ratio of ethylene carbonate / diethyl carbonate of 1M LiPF ₆ of 1: 1 to prepare a sample solution. For each sample solution, potentiostat (manufactured by BioLogic) in a three-electrode electrochemical measurement system using a glassy carbon electrode (3 mmΦ) as a working electrode, a platinum mesh as a counter electrode, and a silver / silver nitrate electrode (manufactured by ALS) as a reference electrode. Voltammetry (sweep speed 5 mV / sec) at room temperature (about 25 ° C.) was performed using VMP3 (trade name). The potential at which the observed reduction current peak was observed was converted to Li / Li ⁺ potential and listed in Table A, and the respective voltammograms are shown in FIGS. The conversion formula is described in the margin * of Table A.

比較例（１） 特開平１１−９７０５９号公報 記載の添加剤
＊ Ｅｐ（対Ｌｉ／Ｌｉ^＋）＝Ｅｐ（測定値：対銀／硝酸銀電位）＋３．１８（Ｖ）

Comparative Example (1) Additive described in JP-A-11-97059 * Ep (vs. Li / Li ⁺ ) = Ep (measured value: silver / silver nitrate potential) + 3.18 (V)

(Example 1 and Comparative Example 1)
-Preparation of electrolyte solution In an electrolyte solution having a volume ratio of ethylene carbonate / diethyl carbonate of 1M LiPF ₆ of 1: 1, the polymerization initiator precursor and the anionic polymerization monomer shown in Table 1 in the amounts described in the table. In addition, a test electrolyte was prepared.
-Production of 2032 type coin battery The positive electrode is produced with 85% by mass of active material: lithium cobaltate (LiCoO ₂ ), conductive auxiliary agent (conductive material): 7% by mass of carbon black, binder: 8% by mass of PVDF (polyvinylidene fluoride). The negative electrode was made of active material: 86% by mass of graphite, conductive auxiliary agent (conductive material): 6% by mass of carbon black, and binder: 8% by mass of PVDF. The separator is made of polypropylene and has a thickness of 25 μm. Using the above positive and negative electrodes and separator, a 2032 type coin battery was prepared for each test electrolyte, and the following items were evaluated. The results are shown in Table 1.

<Battery initial capacity>
Using the 2032 type coin battery produced by the above method, after constant current charging in a thermostatic bath at 30 ° C. until the battery voltage becomes 4.2 V at 0.4 mA (0.2 C), −0.4 mA ( 0.2C), constant current discharge was performed until the battery voltage reached 2.75 V, and this operation was repeated 5 times, and the discharge capacity at the fifth time was defined as the initial discharge capacity.

<Capacity maintenance rate-200 cycles>
Using the 2032 type coin battery produced by the above method, charging at 1 C constant current in a constant temperature bath at 60 ° C. until the battery voltage becomes 4.2 V at 4.0 mA, the current value is 0 at 4.2 V constant voltage. The battery was charged until .12 mA or 2 hours, and then 1 C constant current was discharged at 4.0 mA until the battery voltage reached 2.75 V, resulting in one cycle. This was repeated until 200 cycles were reached, and the discharge capacity (mAh) at the 200th cycle was measured.
Discharge capacity maintenance rate (%) =
(Discharge capacity at the 200th cycle / discharge capacity at the first cycle) × 100

<Charge storage stability-30 days>
Using the 2032 type coin battery produced by the above method, after charging at a constant current of 0.1 C until the battery voltage reaches 4.2 V at 0.4 mA in an environment of 30 ° C., the current value at a constant voltage of 4.2 V Was charged for 2 hours until 0.12 mA, or 0.1 C constant current discharge was performed at 0.4 mA until the battery voltage reached 2.75 V, and the initial discharge capacity was measured. Further, after charging at a constant current of 0.1 C until the battery voltage becomes 4.2 V at 0.4 mA, the battery is charged until the current value becomes 0.12 mA at a constant voltage of 4.2 V or after charging for 2 hours. Was left in an environment of 45 ° C. for 30 days. Then, after taking out to 30 degreeC environment, the discharge capacity when discharging was performed on the same discharge conditions was measured, and the following capacity maintenance rate was computed.
Discharge capacity maintenance rate [Charge storage stability] (%) =
(Discharge capacity after 30 days / initial discharge capacity) × 100

<Notes in the table>
(1) Examples using only styrene (2) Additives described in JP-A-62-86673
Example using 9-fluorenone (3) Combination of additives described in JP-A-11-97059
Example using combination of styrene / bromobenzene (4) Monomer described in JP-A-2000-149989
Example of using benzophenone in combination with styrene (Note) Test results not described are shown as "-"

  As described above, according to the nonaqueous electrolytic solution of the present invention, a sufficient initial capacity can be exhibited, and an improvement in performance can be achieved in capacity maintenance. Specifically, in the examples according to the present invention, 11 to 19 points for the capacity retention rate (200 cycles) and 13 to 24 points for the charge storage stability (30 days) with respect to the electrolyte solution (C11a) not using the additive. However, this is an improvement range that can be sufficiently recognized in practice, and an improvement in the capacity retention rate has been achieved without greatly reducing the initial capacity. That is, in the recent lithium-ion battery in which high performance is being realized and the room for development is limited, the performance is further significantly improved.

(Example 2 and Comparative Example 2)
-Preparation of electrolyte solution The electrolyte initiator and the anionic polymerization monomer shown in Table 2 were added to the electrolyte solution having a volume ratio of ethylene carbonate / ethylmethyl carbonate of 1M LiPF ₆ of 1: 2 as shown in Table 2. A test electrolyte solution was prepared in an amount.
・ Production of 2032 type coin battery The positive electrode is made of active material: lithium cobaltate (LiCoO ₂ ) 85% by mass, conductive auxiliary agent (conductive material): carbon black 7% by mass, binder: PVDF 8% by mass, and the negative electrode is active Material: 94% by mass of lithium titanate (Li ₄ Ti ₅ O ₁₂ ), conductive auxiliary agent (conductive material): carbon black 3% by mass, binder: PVDF 3% by mass. The separator is made of polypropylene and has a thickness of 25 μm. Using the above positive and negative electrodes and separator, a 2032 type coin battery was prepared for each test electrolyte, and the following items were evaluated. The results are shown in Table 2. In Table 2 and later, the battery No. Is omitted, but electrolyte No. The number from which the trailing a is deleted is the battery number. It shall fall under.

<Battery initial capacity>
Measurement was performed in the same manner as in Example 1 and Comparative Example 1. However, the voltage at the time of charging was 2.85V, and the lower limit value of the voltage after discharging was 1.2V.

<Capacity maintenance rate-200 cycles>
Measurement was performed in the same manner as in Example 1 and Comparative Example 1. However, the temperature of the thermostatic bath was 30 ° C.

(Example 3 and Comparative Example 3)
In the same manner as in Example 2 and Comparative Example 2, an electrolytic solution was prepared to produce a 2032 type coin battery. The battery initial capacity was also measured in the same manner as in Example 2 and Comparative Example 2. The results are shown in Table 3. The capacity retention rate (200 cycles) is the same as in Example 2 and Comparative Example 2 except that the voltage at the time of charging is 2.85 V and the lower limit value of the voltage at the time of discharging is 1.2 V. went. The results are shown in Table 3.

(Example 4 and Comparative Example 4)
An electrolytic solution was prepared in the same manner as in Example 2 and Comparative Example 2. A 2032 type coin battery was manufactured as follows.
-Production of 2032 type coin battery The positive electrode is active material: nickel manganese lithium cobaltate (LiNi _1/3 Mn _1/3 Co _1/3 O ₂ ) 85% by mass, conductive auxiliary agent (conductive material): 7% by mass of carbon black , Binder: PVDF 8% by mass, negative electrode is active material: lithium titanate (Li ₄ Ti ₅ O ₁₂ ) 94% by mass, conductive auxiliary agent (conductive material): carbon black 3% by mass, binder: PVDF 3% by mass %. The separator is made of polypropylene and has a thickness of 25 μm. Using the above positive and negative electrodes and separator, a 2032 type coin battery was prepared for each test electrolyte, and the following items were evaluated. The results are shown in Table 4.

The initial battery capacity was measured in the same manner as in Example 2 and Comparative Example 2, except that the charging voltage was 2.95V. The results are shown in Table 4.
The capacity retention rate (200 cycles) is the same as in Example 2 and Comparative Example 2 except that the voltage during charging is 2.95 V and the lower limit of the voltage during discharging is 1.2 V. went. The results are shown in Table 4.

  From the results of Example 2 and the following, it can be seen that the nonaqueous electrolytic solution of the present invention has an improvement effect of maintaining sufficient initial capacity and improving cycle characteristics even under different electrodes and charge / discharge conditions. .

  For convenience of reference, the electrode materials and test conditions used in each example are summarized below.

DESCRIPTION OF SYMBOLS 1 Positive electrode conductive material 2 Positive electrode active material 3 Negative electrode conductive material 4 Negative electrode active material 5 Electrolyte 6 Operation means 7 Wiring 9 Separator 10 Lithium ion secondary battery 12 Separator 14 Positive electrode sheet 16 Negative electrode sheet 18 The outer can 20 which also serves as a negative electrode Insulating plate 22 Sealing plate 24 Positive electrode current collector 26 Gasket 28 Pressure sensitive valve body 30 Current interrupting element 100 Bottomed cylindrical lithium secondary battery

Claims (14)

An electrolytic solution containing an anionic polymerizable monomer, a polymerization initiator precursor, and an organic solvent, wherein the polymerization initiator precursor is (A) a compound represented by the following general formula (1 ′), (B) compound represented by the general formula (2), or, (C) a compound which is reduced on the negative electrode in the potential 0～1.9V (vs. Li equivalent) state, and are one of the said anionic polymerizable monomer The electrolyte solution for nonaqueous secondary batteries whose addition amount with a polymerization initiator precursor is 0.001 mol / l or more and 0.1 mol / l or less, respectively .

(R ¹⁰¹ and R ¹⁰² in the general formula (1 ′) represent an aromatic group or a heteroaromatic group. R ¹⁰¹ and R ¹⁰² are bonded directly or via a linking group, and the C in the formula (1 ′) Forms a 5- to 8-membered ring containing ═O.
R ¹⁰³ and R ^{104 in} the general formula (2) represent an aromatic group or a heteroaromatic group. R ¹⁰³ and R ¹⁰⁴ may be bonded directly or via a linking group to form a 6-8 membered ring containing —C (═O) C (═O) — in the formula (2).
A plurality of compounds represented by the general formula (1 ′) or (2) may be combined to form a multimer. ) The electrolyte solution for a nonaqueous secondary battery according to claim 1, wherein the compound (C) is a compound represented by the following general formula (1).

(R ¹ and R ^{2 in} the general formula (1) represent an aromatic group or a heteroaromatic group. R ¹ and R ² are bonded directly or via a linking group, and C = O in the formula (1) A 5- to 8-membered ring containing
A plurality of compounds represented by the general formula (1) may be combined to form a multimer. ) The electrolyte solution for a non-aqueous secondary battery according to claim 1 or 2, wherein the polymerization initiator precursor is a compound represented by the following general formula (1) or (2).

(R ¹ and R ^{2 in} the general formula (1) represent an aromatic group or a heteroaromatic group. R ¹ and R ² are bonded directly or via a linking group, and C = O in the formula (1) A 5- to 8-membered ring containing
However, when the compound represented by the formula (1) is a compound that is reduced on the negative electrode at a potential exceeding 1.9 V (vs. lithium), R ¹ and R ² are C═O in the formula (1). 5 to 8 membered ring is formed.
R ¹⁰³ and R ^{104 in} the general formula (2) represent an aromatic group or a heteroaromatic group. R ¹⁰³ and R ¹⁰⁴ may be bonded directly or via a linking group to form a 6-8 membered ring containing —C (═O) C (═O) — in the formula (2).
A plurality of compounds represented by general formula (1) or (2) may be combined to form a multimer. ) The non-aqueous secondary battery according to any one of claims 1 to 3, wherein the anionic polymerizable monomer is at least one of compounds represented by the following general formulas (3-a) to (3-d). Electrolyte.

(In General Formula (3-a), R ³ represents a hydrogen atom or an alkyl group. R ⁴ represents an aromatic group, a heterocyclic group, a nitrile group, an alkoxy group, or an acyloxy group.)
(In General Formula (3-b), R ⁵ represents a hydrogen atom, an alkyl group, or a cyano group. R ⁶ represents an alkyl group or an alkoxy group.)
(In the general formula (3-c), R ⁷ and R ⁸ represent a hydrogen atom, an alkyl group or an aromatic group. X, Y, and Z are independently —O—, —S—, —C (= O) -, - C (= S) -, - N (R) -, - S (O) - and -SO ₂ - represents a divalent linking group selected from, R represents an alkyl group or an aromatic group Represents.)
(In the general formula (3-d), R ⁹ represents an alkyl group or a hydrogen atom.)
(The compounds represented by the general formulas (3-a) to (3-d) may form multimers linked to each other at R ^{3 to} R ⁹ ).   The polymerization initiator precursor is a 9-fluorenone compound, anthrone compound, xanthone compound, dibenzosuberone compound, dibenzosuberone compound, anthraquinone compound, biantronyl compound, biantron compound, substituted benzophenone compound, dibenzoyl compound, and derivatives thereof The electrolyte solution for nonaqueous secondary batteries according to any one of claims 1 to 4, which is at least one selected from the group consisting of: The polymerization initiator precursor is at least any one selected from the group consisting of compounds represented by the following formulas (1-1) to (1-27) or derivatives thereof. The electrolyte solution for non-aqueous secondary batteries of Claim 1.

(General formula (1-24) is a 4-fluoro product or a 4,4′-difluoro product.)   The polymerization initiator precursor is a compound represented by the formulas (1-1) to (1-12), (1-15) to (1-23), (1-26) and (1-27). Alternatively, the electrolyte solution for a non-aqueous secondary battery according to claim 6, which is at least one selected from the group consisting of derivatives thereof.   The nonionic secondary battery according to any one of claims 1 to 7, wherein the anion polymerizable monomer is at least one of an aromatic substituted vinyl compound, a vinylene carbonate compound, or an acrylic compound. Electrolytic solution. The electrolyte solution, the periodic table family or non-aqueous liquid electrolyte for a secondary battery according to any one of the second group metal belonging to ion or claim 1-8, further comprising a salt thereof. An electrolyte for a non-aqueous secondary battery according to any one of claims 1 to 9 , a positive electrode capable of inserting and releasing ions of a metal belonging to Group 1 or Group 2 of the periodic table, A nonaqueous electrolyte secondary battery comprising a negative electrode capable of insertion / release or dissolution / deposition. The nonaqueous electrolyte secondary battery according to claim 10 , wherein lithium titanate is applied as an active material of the negative electrode. An electrolyte solution kit for a non-aqueous secondary battery using a mixture of a first agent and a second agent,
The first agent contains an ion of a metal belonging to Group 1 or Group 2 of the Periodic Table or a metal salt containing the same, the second agent contains an anionically polymerizable monomer, and (A) the following general formula ( 1 ′), (B) a compound represented by the following general formula (2), or (C) a compound reduced on the negative electrode at a potential of 0 to 1.9 V (vs. lithium). A polymerization initiator precursor comprising the above-mentioned first agent, the second agent, and at least one of the other agents, the anionic polymerizable monomer and the polymerization initiator precursor, The kit of the electrolyte solution for non-aqueous secondary batteries added so that the addition amount after mixing may be 0.001 mol / l or more and 0.1 mol / l or less, respectively .

(R ¹⁰¹ and R ¹⁰² in the general formula (1 ′) represent an aromatic group or a heteroaromatic group. R ¹⁰¹ and R ¹⁰² are bonded directly or via a linking group, and the C in the formula (1 ′) Forms a 5- to 8-membered ring containing ═O.
R ¹⁰³ and R ^{104 in} the general formula (2) represent an aromatic group or a heteroaromatic group. R ¹⁰³ and R ¹⁰⁴ may be bonded directly or via a linking group to form a 6-8 membered ring containing —C (═O) C (═O) — in the formula (2).
A plurality of the compounds represented by the general formula (1 ′) or (2) may be combined to form a multimer. The kit for an electrolyte solution for a non-aqueous secondary battery according to claim 12 , wherein the compound (C) is a compound represented by the following general formula (1).

(R ¹ and R ^{2 in} the general formula (1) represent an aromatic group or a heteroaromatic group. R ¹ and R ² are bonded directly or via a linking group, and C = O in the formula (1) A 5- to 8-membered ring containing
A plurality of compounds represented by the general formula (1) may be combined to form a multimer. ) The polymerization initiator precursor to be contained in at least one of the first agent, the second agent, and the other agent is any one of the compounds represented by the following general formula (1) or (2) The kit of the electrolyte solution for nonaqueous secondary batteries of a certain 12 or 13 .

(R ¹ and R ^{2 in} the general formula (1) represent an aromatic group or a heteroaromatic group. R ¹ and R ² are bonded directly or via a linking group, and C = O in the formula (1) A 5- to 8-membered ring containing
However, when the compound represented by the formula (1) is a compound that is reduced on the negative electrode at a potential exceeding 1.9 V (vs. lithium), R ¹ and R ² are C═O in the formula (1). 5 to 8 membered ring is formed.
R ¹⁰³ and R ^{104 in} the general formula (2) represent an aromatic group or a heteroaromatic group. R ¹⁰³ and R ¹⁰⁴ may be bonded directly or via a linking group to form a 6-8 membered ring containing —C (═O) C (═O) — in the formula (2).
A plurality of compounds represented by general formula (1) or (2) may be combined to form a multimer. )

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