JP6391028B2 - Electrolyte, lithium ion battery and lithium ion capacitor - Google Patents

Description

  The present invention relates to an electrolytic solution, a lithium ion battery and a lithium ion capacitor using the electrolytic solution.

  Lithium ion batteries and lithium ion capacitors, including lithium ion secondary batteries, can achieve higher energy density in charge and discharge than lead batteries and nickel cadmium batteries. Utilizing this characteristic, application to portable electronic devices such as mobile phones and notebook personal computers is widespread. Recently, development of a secondary battery that is particularly lightweight and capable of obtaining a high energy density has been underway. Further, there is a demand for miniaturization and long life. In addition to portable electronic devices, use as large storage batteries such as hybrid vehicles (HEV), plug-in hybrid vehicles (PHEV), electric vehicles (EV), airplanes and smart grids has begun.

As electrolytes for lithium ion batteries such as lithium ion secondary batteries and capacitors, ethylene carbonate, propylene carbonate having high dielectric constant, diethyl carbonate having high viscosity, and carbonate-based solvents in combination of these and lithium hexafluorophosphate Combinations with electrolyte salts such as (LiPF ₆ ) are widely used. These substances have high conductivity and are stable in potential. Attempts have been made to improve battery performance by further adding various functional additives to the electrolytic solution (see Patent Documents 1 to 5).

JP 2000-123865 A JP 2002-074439 A JP 2007-005242 A JP 2007-095657 A JP2012-119151A

  The present invention provides a high-performance electrolytic solution for use in lithium ion batteries, lithium ion capacitors, etc., in particular, an electrolytic solution with a small amount of an organic compound that improves the penetration rate of a carbonate-based solvent into the negative electrode. It is an object of the present invention to provide a lithium ion battery and a lithium ion capacitor.

The above problem has been solved by the following means.
(1) An electrolytic solution in which an electrolyte is dissolved in a nonaqueous solvent including a carbonate-based solvent, and is used in combination with a negative electrode, which contains a compound represented by the following general formula (I).

In the general formula (I), X represents a saturated hydrocarbon residue which may contain an n1 + n2 valent ether bond represented by any one of the following general formulas (x1) to (x6) . L ¹ is to display the group selected from the following formulas (a1 ') and (a2'). L ² represents a divalent linking group having at least one divalent linking group having an oxygen atom. R ¹ and R ² each independently represents an alkyl group or a cycloalkyl group. n1 represents an integer of 3 or more, and n2 represents an integer of 0 or more. when n1 is 3 or more, a plurality of ^{-L 1} -R 1 may be the same or different and also, when n2 is 2 or more, a plurality of ^{-L 2} -R 2 has good be the same or different.

In the general formulas (x1) to (x6), R ^C1 represents a hydrogen atom or an alkyl group. nc1 to nc5 each independently represents an integer of 1 to 5, and nc6 to nc10 each independently represents 0 or 1.
In the general formulas (a1 ′) and (a2 ′), * represents a bond that bonds to X.
However, when L ¹ is a group represented by the general formula (a2 ′), in the general formula (x1), nc6 is 1, and in the general formula (x2), R ^C1 is an alkyl group, or nc7 is 1.
(2) The electrolytic solution according to (1), wherein 0.001 to 20% by mass of the compound represented by the general formula (I) is contained in the electrolytic solution.
( 3 ) The electrolytic solution according to (1) or (2) , wherein L ² is a group selected from the following general formula (b1) and general formula (b2).

In general formulas (b1) and (b2), Lb represents a single bond, an alkylene group or a cycloalkylene group. nb represents an integer of 1 to 5. Where * shows the bond that binds to the X.

(4) The electrolyte solution according to any one of (1) to (3), wherein n2 is 0.
(5) The electrolyte solution according to any one of (1) to (4), wherein the compound represented by the general formula (I) has a molecular weight of 100 to 2000.

(6 ) A lithium ion battery using the electrolytic solution according to any one of (1) to ( 5 ).
( 7 ) The lithium ion capacitor using the electrolyte solution as described in any one of (1)-( 5 ).

In this specification, when there are a plurality of substituents or linking groups indicated by a specific symbol, or when a plurality of substituents etc. (same definition of the number of substituents) are specified simultaneously or alternatively, The substituents and the like may be the same as or different from each other. Further, when a plurality of substituents and the like are close to each other, they may be bonded to each other to form a ring. In the case of a substituent on the ring, a plurality of substituents are bonded to form a ring, and the original ring And may form a condensed ring.
In the present specification, a numerical range expressed using “to” means a range including numerical values described before and after “to” as a lower limit value and an upper limit value.

With the polyvalent ester compound of the present invention, it is possible to improve the penetration rate of the carbonate-based solvent contained in the electrolytic solution used in lithium ion batteries, lithium ion capacitors and the like into the negative electrode, thereby achieving high performance.
For this reason, according to the present invention, the performance of the electrolytic solution used in lithium ion batteries, lithium ion capacitors, etc. is improved, and in particular, the electrolytic solution in which the penetration rate of the carbonate-based solvent into the negative electrode is improved with a small amount of an organic compound, It has become possible to provide a lithium ion battery and a lithium ion capacitor using the same.
Further, it is considered that a good solid electrolyte interface (SEI; Solid Electrolyte Interface) is formed by adding a polyvalent ester compound, so that deterioration of the electrolytic solution is suppressed and cycle characteristics can be improved.

  The above and other features and advantages of the present invention will become more apparent from the following description, with reference where appropriate to the accompanying drawings.

FIG. 1 is a cross-sectional view schematically showing the mechanism of a lithium secondary battery according to a preferred embodiment of the present invention. FIG. 2 is a cross-sectional view showing a specific configuration of a lithium secondary battery according to a preferred embodiment of the present invention. FIG. 3 is an explanatory diagram of a method for evaluating the penetration rate of the carbonate-based solvent into the negative electrode.

The present invention is described in detail below.
In addition, description of the component requirement described below may be made | formed based on typical embodiment and a specific example. However, the present invention is not limited to such an embodiment.

[Compound of the present invention]
The electrolytic solution of the present invention contains a compound represented by the following formula (I).

In the general formula (I), X represents an n1 + n2-valent saturated hydrocarbon residue having 1 to 30 carbon atoms. However, when X has 2 to 30 carbon atoms, the saturated hydrocarbon residue may contain an ether bond. L ¹ represents a divalent linking group having at least one ester bond, and L ² represents a divalent linking group having at least one divalent linking group having an oxygen atom. R ¹ and R ² each independently represents an alkyl group or a cycloalkyl group. n1 represents an integer of 3 or more, and n2 represents an integer of 0 or more. When n1 is 3 or more, the plurality of -L ¹ -R ¹ may be the same or different, and when n2 is 2 or more, the plurality of -L ² -R ² may be the same or different.

L ¹ is a divalent linking group having at least one ester bond, and may be an ester bond only or an ester bond via a linking group. In this case, the ester bond may be —O—C (═O) — or —C (═O) —O—. When a linking group is interposed, the linking group is preferably a divalent saturated aliphatic hydrocarbon residue, preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms. Among these, the divalent saturated aliphatic hydrocarbon residue is more preferably an alkylene group or a cycloalkylene group, and more preferably an alkylene group. In the case of an alkylene group, an ether bond (—O—) may be interposed therebetween.

L ¹ is preferably a group selected from the following general formula (a1) and general formula (a2).

  In general formulas (a1) and (a2), La represents a single bond, an alkylene group or a cycloalkylene group. na represents an integer of 1 to 5. Here, * indicates a bond that bonds with X.

  The alkylene group may be linear or branched, and the number of carbon atoms is preferably 1 to 30, and more preferably 1 to 20. For example, ethylene, propylene, trimethylene, tetramethylene, hexamethylene, and octamethylene are mentioned.

  The ring of the cycloalkylene group is preferably a 3- to 7-membered ring, more preferably a 5- or 6-membered ring. Moreover, 3-20 are preferable, 5-20 are more preferable, and 5-16 are more preferable. Examples include cyclopropylene, cyclopentylene, cyclohexylene, and cycloheptylene.

  na represents an integer of 1 to 5, preferably an integer of 1 to 3, more preferably 1 or 2, and particularly preferably 1.

  In the present invention, La is particularly preferably a single bond.

When n1 is 3 or more, the plurality of L ¹ may be only ^one of the general formulas (a1) and (a2), or these may be mixed.

L ² represents a divalent linking group having at least one divalent linking group having an oxygen atom. Here, the divalent linking group having an oxygen atom is a divalent functional group or a divalent bond, such as an ether bond, a carbonate bond, a sulfonyl bond, a urethane bond, —OSO ₂ —, an amide bond, etc. And the bond in the substituents exemplified in the substituent T in (the direction of the bond may be on the R ² side or on the X side). L ² is preferably a divalent linking group having at least one ether bond or carbonate bond. In addition, even if it is only an ether bond or a carbonate bond, it may have an ether bond or a carbonate bond via a linking group. When a linking group is interposed, the linking group is preferably a divalent saturated aliphatic hydrocarbon residue, preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms. Among these, the divalent saturated aliphatic hydrocarbon residue is more preferably an alkylene group or a cycloalkylene group, and more preferably an alkylene group.
The same applies to a divalent linking group having an oxygen atom other than an ether bond or a carbonate bond.

L ² is preferably a group selected from the following general formula (b1) and general formula (b2).

  In general formulas (b1) and (b2), Lb represents a single bond, an alkylene group or a cycloalkylene group. nb represents an integer of 1 to 5. Here, * indicates a bond that bonds with X.

  Lb is synonymous with La in the general formulas (a1) and (a2), and the preferred range is also the same. nb is synonymous with na in the general formulas (a1) and (a2), and the preferred range is also the same.

R ¹ and R ² each independently represents an alkyl group or a cycloalkyl group.
The alkyl group may be linear or branched. 1-10 are preferable, as for carbon number of an alkyl group, 1-8 are more preferable, 1-4 are more preferable, and 1 or 2 is especially preferable. Examples include methyl, ethyl, n-propyl, isopropyl, n-butyl, s-butyl, isobutyl, t-butyl, n-hexyl, n-octyl, 2-ethylhexyl, isooctyl, n-decyl and isodecyl.
The ring of the cycloalkyl group is preferably a 3- to 7-membered ring, more preferably a 5- or 6-membered ring. Moreover, 3-10 are preferable, as for carbon number of a cycloalkyl group, 5-10 are more preferable, and 5 or 6 is more preferable. Examples include cyclopropyl, cyclopentyl, cyclohexyl, and cycloheptyl.
In the present invention, R ¹ and R ² are preferably alkyl groups.

n1 represents an integer of 3 or more, preferably 3 to 12, more preferably 3 to 8, and still more preferably 3 to 6.
n2 represents an integer of 0 or more, preferably 0 to 10, more preferably 0 to 3, further preferably 0 to 2, and particularly preferably 0.

When n1 is 3 or more, the plurality of -L ¹ -R ¹ may be the same or different, and when n2 is 2 or more, the plurality of -L ² -R ² may be the same or different.

  X represents an n1 + n2 valent saturated hydrocarbon residue having 1 to 30 carbon atoms. However, when X has 2 to 30 carbon atoms, the saturated hydrocarbon residue may contain an ether bond. In this case, the ether bond is preferably located between the saturated hydrocarbon residues.

  1-26 are preferable, as for carbon number of X, 1-20 are more preferable, 2-20 are more preferable, and 3-20 are especially preferable.

  In the present invention, X is preferably any of the following general formulas (x1) to (x6).

In the general formulas (x1) to (x6), R ^C1 represents a hydrogen atom or an alkyl group. nc1 to nc5 each independently represents an integer of 1 to 5, and nc6 to nc10 each independently represents 0 or 1.

1-4 are preferable, as for carbon number of the alkyl group in R ^<C1 >, 1-3 are more preferable, and 1 or 2 is more preferable. The alkyl group may be linear or branched, but is preferably linear.
Examples of the alkyl group include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, and t-butyl.

nc1 to nc5 are preferably an integer of 1 to 4, and more preferably an integer of 1 to 3.
However, in the present invention, X is an n1 + n2 valent saturated hydrocarbon residue represented by any one of the above general formulas (x1) to (x6), which may contain an ether bond, and L ¹ is *- A group selected from C (═O) —O— and * —O—C (═O) — (* represents a bond to be bonded to X).
Here, in the present invention, when L ¹ is a group represented by * —O—C (═O) —, in general formula (x1), nc6 is 1, and in general formula (x2), R ^C1 Is an alkyl group or nc7 is 1.

  100-2000 are preferable, as for the molecular weight of the compound represented by general formula (I), 100-1000 are more preferable, and 100-800 are more preferable.

Specific examples of the compound represented by the general formula (I) of the present invention are given below. In addition, this invention is limited to these and is not interpreted.
However, compounds A-1, A-2, A-11, A-22, A-27 and A-28 are reference examples.

  The method for producing the compound represented by the general formula (I) of the present invention is not particularly limited. For example, the compound is synthesized by esterification described in European Patent Application No. 2272818 or a method analogous thereto. be able to.

  The compounds represented by the general formula (I) of the present invention may be used singly or in combination of two or more.

  The content of the compound represented by the general formula (I) in the electrolytic solution is preferably 0.001 to 20% by mass, more preferably 0.01 to 10% by mass in the electrolytic solution. 1-5 mass% is further more preferable, and 0.1-2 mass% is especially preferable.

  The compound represented by the general formula (I) of the present invention can increase the penetration rate of the electrolytic solution into the electrode in a small amount.

(Electrolytes)
The electrolyte used in the electrolytic solution of the present invention is preferably a salt of a metal ion belonging to Group 1 or Group 2 of the periodic table. The metal ion salt to be used is appropriately selected depending on the intended use of the electrolytic solution. For example, lithium salt, potassium salt, sodium salt, calcium salt, magnesium salt and the like can be mentioned. When used in a secondary battery or the like, lithium salt is preferable from the viewpoint of output. When the electrolytic solution of the present invention is used as a non-aqueous electrolytic solution for a lithium ion secondary battery, a lithium salt may be selected as a metal ion salt. As a lithium salt, the lithium salt normally used for the electrolyte of the non-aqueous electrolyte solution for lithium ion secondary batteries is preferable, For example, what is described below is preferable.

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

(L-3) Oxalatoborate salt: lithium bis (oxalato) borate, lithium difluorooxalatoborate, etc.

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 ) are preferred, and lithium imides 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 ) More preferred are salts. Here, Rf ¹ and Rf ² each represent a perfluoroalkyl group.
In addition, the electrolyte used for electrolyte solution may be used individually by 1 type, or may combine 2 or more types arbitrarily.

  The electrolyte in the electrolytic solution (preferably a metal ion belonging to Group 1 or Group 2 of the periodic table or a metal salt thereof) is added in such an amount that a preferable salt concentration described below in the method for preparing the electrolytic solution is obtained. It is preferable. The salt concentration is appropriately selected depending on the purpose of use of the electrolytic solution, but is generally 10% by mass to 50% by mass, more preferably 15% by mass to 30% by mass, based on the total mass of the electrolytic solution. The molar concentration is preferably 0.5M to 1.5M. In addition, when evaluating as a density | concentration of ion, what is necessary is just to calculate by salt conversion with the metal applied suitably.

(Non-aqueous solvent)
As the non-aqueous solvent used in the present invention, an aprotic organic solvent is preferable, and an aprotic organic solvent having 2 to 10 carbon atoms is particularly preferable.
Such non-aqueous solvents include carbonate compounds, lactone compounds, chain or cyclic ether compounds, ester compounds, nitrile compounds, amide compounds, oxazolidinone compounds, nitro compounds, chain or cyclic sulfone or sulfoxide compounds, phosphoric acid. Examples include esters.
In addition, as a preferable bond, a compound having an ether bond, a carbonyl bond, an ester bond or a carbonate bond is preferable. These compounds may have a substituent, for example, the below-mentioned substituent T is mentioned.

Examples of the non-aqueous solvent 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, ethyl propionate, butyric acid Methyl, methyl isobutyrate, methyl trimethylacetate, ethyl trimethylacetate, acetonitrile, glutaronitrile, adiponitrile, methoxyacetonitrile, 3-methoxypropionitrile, N, Examples thereof include N-dimethylformamide, N-methylpyrrolidinone, N-methyloxazolidinone, N, N′-dimethylimidazolidinone, nitromethane, nitroethane, sulfolane, trimethyl phosphate, dimethyl sulfoxide and dimethyl sulfoxide. These may be used alone or in combination of two or more. Among these, at least one member selected from the group consisting of ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate and ethyl methyl carbonate, and γ-butyrolactone is preferable. Particularly, high viscosity (high dielectric constant) such as ethylene carbonate or propylene carbonate. A combination of a solvent (for example, relative dielectric constant ε ≧ 30) and a low viscosity solvent (for example, viscosity ≦ 1 mPa · s) such as dimethyl carbonate, ethyl methyl carbonate, or diethyl carbonate is more preferable. By using a mixed solvent of such a combination, the dissociation property of the electrolyte salt and the ion mobility are improved.
The nonaqueous solvent used in the present invention is not limited to these.

(Functional additives)
The electrolyte solution of the present invention preferably contains various functional additives in order to improve flame retardancy, improve cycle characteristics, improve capacity characteristics, and the like.
Examples of functional additives that are preferably applied to the electrolytic solution of the present invention are shown below.

<Aromatic compounds>
Aromatic compounds include biphenyl compounds and alkyl-substituted benzene compounds. The biphenyl compound has a partial structure in which two benzene rings are bonded by a single bond, and the benzene ring may have a substituent, and preferred substituents are alkyl groups having 1 to 4 carbon atoms (for example, Methyl, ethyl, propyl, t-butyl and the like) and aryl groups having 6 to 10 carbon atoms (for example, phenyl, naphthyl and the like).
Specific examples of the biphenyl compound include biphenyl, o-terphenyl, m-terphenyl, p-terphenyl, 4-methylbiphenyl, 4-ethylbiphenyl, and 4-tert-butylbiphenyl.
The alkyl-substituted benzene compound is preferably a benzene compound substituted with an alkyl group having 1 to 10 carbon atoms. Specifically, ethylbenzene, isopropylbenzene, cyclohexylbenzene, t-amylbenzene, t-butylbenzene, and tetrahydrohydronaphthalene are used. Can be mentioned.

<Compound having a halogen atom>
The halogen atom contained in the compound having a halogen atom is preferably a fluorine atom, a chlorine atom or a bromine atom, and more preferably a fluorine atom. The number of halogen atoms is preferably 1 to 6, and more preferably 1 to 3. The compound having a halogen atom is preferably a carbonate compound substituted with a fluorine atom, a polyether compound having a fluorine atom, or a fluorine-substituted aromatic compound.
The carbonate compound substituted with a halogen atom may be either linear or cyclic. From the viewpoint of ion conductivity, a cyclic carbonate compound having a high coordination property of an electrolyte salt (for example, lithium ion) is preferable, and a 5-membered cyclic carbonate compound is particularly preferable.
Preferred specific examples of the carbonate compound substituted with a halogen atom are shown below. Among these, compounds of Bex1 to Bex4 are particularly preferable, and Bex1 is most preferable.

<Polymerizable compound>
As the polymerizable compound, a compound having a carbon-carbon double bond is preferable. A carbonate compound having a double bond such as vinylene carbonate or vinyl ethylene carbonate, an acryloyloxy group, a methacryloyloxy group, a cyanoacryloyloxy group, α-CF _3. A compound having a group selected from an acryloyloxy group and a compound having a styryl group are preferred, and a carbonate compound having a double bond or a compound having two or more polymerizable groups in the molecule is more preferred.

<Compound having a sulfur atom>
The compound having a sulfur atom is preferably a compound having a —SO ₂ —, —SO ₃ —, —OS (═O) O— bond, and a cyclic sulfur-containing compound such as propane sultone, propene sultone, ethylene sulfite, Sulfonate esters are preferred.

  Examples of the cyclic sulfur-containing compound include the following Eex1 to Eex12.

<Compound having a silicon atom>
The compound having a silicon atom is preferably a compound represented by the following general formula (F1) or (F2).

In the general formulas (F1) and (F2), R ^F1 represents an alkyl group, an alkenyl group, an acyl group, an acyloxy group, or an alkoxycarbonyl group.
R ^F2 represents an alkyl group, an alkenyl group, an alkynyl group or an alkoxy group.
A plurality of R ^F1 and R ^{F2 in} one formula may be different from each other or the same.

<Nitrile compound>
As the nitrile compound, acetonitrile, propionitrile, isobutyronitrile, succinonitrile, malononitrile, glutaronitrile, adiponitrile, 2-methylglutanonitrile, hexanetricarbonitrile, propanetetracarbonitrile and the like are preferable. Particularly preferred are succinonitrile, malononitrile, glutaronitrile, adiponitrile, 2-methylglutanonitrile, hexanetricarbonitrile, and propanetetracarbonitrile.

<Compound having boron atom>
The compound having a boron atom is preferably a compound represented by the following general formulas (H1) to (H3).

In the general formulas (H1) to (H3), R ^H1 and R ^{H4 to} R ^H11 are each independently an alkyl group, an alkoxy group, an alkylcarbonyloxy group, an aryl group, an aryloxy group, an arylcarbonyloxy group, or a heteroaryl group. Represents a heteroaryloxy group, a heteroarylcarbonyloxy group, an alkylamino group, an arylamino group, a cyano group, a carbamoyl group or a halogen atom. Here, a plurality of groups may be bonded to each other to form a ring. R ^H2 and R ^H3 each independently represents an alkyl group, an alkylcarbonyl group, an aryl group, an arylcarbonyl group, a heteroaryl group, a heteroarylcarbonyl group, or a boron atom. Here, a plurality of groups may be bonded to each other to form a ring. Z ⁺ represents an inorganic or organic cation, and is preferably an ammonium cation, Li ⁺ , Na ⁺ , or K ⁺ .
Specific examples of the compound having a boron atom include the following structures, and more preferably Hex1 to Hex2.

<Metal complex compound>
In the present invention, a metal complex compound may be contained.
As such a metal complex compound, a transition metal complex or a rare earth complex is preferable. Especially, the complex represented by either of the following general formula (H-1)-(H-3) is preferable.

In the general formulas (H-1) to (H-3), X ^H and Y ^H each independently represent a methyl group, an n-butyl group, a bis (trimethylsilyl) amino group, or a thioisocyanate group. Here, X ^H and Y ^H are bonded to one another, with M ^H, it may form a cyclic alkenyl group (butadiene coordinated metallacycle).
^MH represents a transition element or a rare earth element. Specifically, ^MH is preferably Fe, Ru, Cr, V, Ta, Mo, Ti, Zr, Hf, Y, La, Ce, Sw, Nd, Lu, Er, Yb, and Gd. m ^H and n ^H are integers satisfying 0 ≦ m ^H + n ^H ≦ 3. n ^H + m ^H is preferably 1 or more. When n ^H and m ^H are 2 or more, the 2 or more groups defined therein may be different from each other.

  The metal complex compound is also preferably a compound having a partial structure represented by the following general formula (H-4).

^{M H - (NR 1H R 2H} ) q H ··· formula (H-4)

In General Formula (H-4), ^MH represents a transition element or a rare earth element, and is synonymous with General Formulas (H-1) to (H-3), and a preferable range is also the same.

R ^1H and R ^2H are each independently a hydrogen atom, an alkyl group (preferably having 1 to 6 carbon atoms), an alkenyl group (preferably having 2 to 6 carbon atoms), an alkynyl group (preferably having 2 to 6 carbon atoms), aryl It represents a group (preferably having 6 to 14 carbon atoms), a heteroaryl group (preferably having 3 to 6 carbon atoms), an alkylsilyl group (preferably having 1 to 6 carbon atoms) or a halogen atom. R ^1H and R ^2H may be bonded to each other to form a ring. Such a ring is preferably a 5- to 6-membered ring, and examples thereof include a pyrrolidine ring, a piperidine ring, a piperazine ring, a morpholine ring, and a thiomorpholine ring. Preferable examples of R ^1H and R ^2H include examples of the substituent T described later. Of these, methyl, ethyl, and trimethylsilyl are preferable.
q ^H represents an integer of 1 to 4, and an integer of 2 to 4 is preferable. More preferably, it is 2 or 4. When q ^H is 2 or more, where a plurality of groups as defined may be the same or different from each other.

The metal complex compound is also preferably a compound represented by any one of the following general formulas.

・ M ^h
The central metal ^M h is, Ti, Zr, ZrO, Hf , V, Cr, Fe, Ce is particularly preferred, Ti, Zr, Hf, V , Cr is the most preferred.

R ^3h , R ^5h and R ^{7h to} R ^10h
R ^3h , R ^5h and R ^{7h to} R ^10h represent a substituent. Among these, an alkyl group, an alkoxy group, an aryl group, an alkenyl group, and a halogen atom are preferable, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, and 2 carbon atoms. -6 alkenyl groups are more preferred, with methyl, ethyl, propyl, isopropyl, isobutyl, t-butyl, perfluoromethyl, methoxy, phenyl, ethenyl being more preferred.

・ R ^33h and R ^55h
R ^33h and R ^55h represent a hydrogen atom or a substituent of R ^3h . ^Examples of the substituent for R ^3h include the substituent T described later.

・ Y ^h
Y ^h is preferably an alkyl group having 1 to 6 carbon atoms or a bis (trialkylsilyl) amino group, and more preferably methyl or bis (trimethylsilyl) amino.

· ^{L h, m} h and ^{o h}
l ^{h, m h} and ^{o h} represents an integer of 0 to 3, preferably an integer of 0 to 2. When l ^h , m ^h and o ^h are 2 or more, the plurality of structural portions defined therein may be the same as or different from each other.

・ L ^h
L ^h is preferably an alkylene group, a cycloalkylene group, or an arylene group, more preferably a cycloalkylene group having 3 to 6 carbon atoms, or an arylene group having 6 to 14 carbon atoms, and further preferably cyclohexylene or phenylene.

<Imide compound>
As the imide compound, from the viewpoint of oxidation resistance, an imide compound in which all of the hydrogen atoms on the carbon atom are fluorinated is preferable, and a perfluorinated sulfonimide compound is preferable, specifically, perfluorinated. A sulfoimide lithium compound is mentioned.
Specific examples of the imide compound include the following structures, and Cex1 and Cex2 are more preferable.

  In addition to the above, the electrolytic solution of the present invention may contain at least one selected from a negative electrode film forming agent, a flame retardant, an overcharge preventing agent and the like. The content ratio of these functional additives in the nonaqueous electrolytic solution is not particularly limited, and is preferably 0.001% by mass to 10% by mass with respect to the entire nonaqueous electrolytic solution (including the electrolyte). By adding these compounds, it is possible to suppress the rupture of the battery at the time of abnormality due to overcharge, or to improve the capacity maintenance characteristic and cycle characteristic after high temperature storage.

In addition, in the present specification, regarding the indication of a compound (for example, when referring to a compound with a suffix), in addition to the compound itself, when the compound has a dissociable group, it is used to mean its salt and its ion. .
In the present specification, a substituent that does not specify substitution / non-substitution (the same applies to a linking group) means that the group may have an arbitrary substituent unless otherwise specified. This is also synonymous for compounds that do not specify substitution / non-substitution. Preferred substituents include the following substituent T. Unless otherwise specified, the substituent T is also referred to when simply referred to as a substituent, and each group such as an alkyl group is also referred to the corresponding group of the 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, etc.), an alkynyl group (preferably an alkynyl group having 2 to 20 carbon atoms such as ethynyl, butynediynyl, phenylethynyl, etc.), 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, for example, Phenyl, 1-naphthyl, 4-methoxyphenyl 2-chlorophenyl, 3-methylphenyl and the like), a heterocyclic group (preferably a heterocyclic group having 2 to 20 carbon atoms, preferably a 5- or 6-membered ring having at least one oxygen atom, sulfur atom, nitrogen atom) A heterocyclic group is preferable, for example, 2-pyridyl, 4-pyridyl, 2-imidazolyl, 2-benzimidazolyl, 2-thiazolyl, 2-oxazolyl, etc., an alkoxy group (preferably an alkoxy group having 1 to 20 carbon atoms, such as , Methoxy, ethoxy, isopropyloxy, benzyloxy, etc.), aryloxy groups (preferably aryloxy groups having 6 to 26 carbon atoms, such as phenoxy, 1-naphthyloxy, 3-methylphenoxy, 4-methoxyphenoxy, etc.) An alkoxycarbonyl group (preferably an alkoxy group having 2 to 20 carbon atoms) Bonyl groups such as ethoxycarbonyl, 2-ethylhexyloxycarbonyl and the like, amino groups (preferably including amino groups having 0 to 20 carbon atoms, alkylamino groups, arylamino groups, such as amino, N, N-dimethyl, etc. Amino, N, N-diethylamino, N-ethylamino, anilino, etc.), sulfamoyl groups (preferably sulfamoyl groups having 0 to 20 carbon atoms, such as N, N-dimethylsulfamoyl, N-phenylsulfamoyl, etc.) ), An acyl group (preferably an acyl group having 1 to 20 carbon atoms, such as acetyl, propionyl, butyryl, benzoyl, etc.), an acyloxy group (preferably an acyloxy group having 1 to 20 carbon atoms, such as acetyloxy, benzoyl) Oxy, etc.), a carbamoyl group (preferably having 1 to 20 carbon atoms) A carbamoyl group such as N, N-dimethylcarbamoyl, N-phenylcarbamoyl, etc., an acylamino group (preferably an acylamino group having 1 to 20 carbon atoms such as acetylamino, benzoylamino, etc.), an alkylthio group (preferably carbon An alkylthio group having 1 to 20 atoms such as methylthio, ethylthio, isopropylthio, benzylthio, etc., an arylthio group (preferably an arylthio group having 6 to 26 carbon atoms such as phenylthio, 1-naphthylthio, 3-methylphenylthio) 4-methoxyphenylthio etc.), an alkyl or arylsulfonyl group (preferably an alkyl or arylsulfonyl group having 1 to 20 carbon atoms, such as methylsulfonyl, ethylsulfonyl, benzenesulfonyl etc.), a hydroxy group, Anomoto, halogen atom (e.g. fluorine atom, a chlorine atom, a bromine atom, an iodine atom) and the like.
Each group may be further substituted with the above-described substituent T. For example, an aralkyl group in which an aryl group is substituted for an alkyl group.

  When a compound or a substituent / linking group includes an alkyl group / alkylene group, an alkenyl group / alkenylene group, an alkynyl group / alkynylene group, etc., these may be cyclic or linear, and may be linear or branched These may be substituted as described above or may be unsubstituted.

[Method for preparing electrolytic solution]
The nonaqueous electrolytic solution of the present invention is prepared by a conventional method by dissolving each of the above components in the nonaqueous electrolytic solution solvent, including an example in which a lithium salt is used as a metal ion salt.

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 effect of the invention is not hindered. Here, substantially not containing means that the concentration of water is 200 ppm (mass basis) or less, preferably 100 ppm or less, more preferably 20 ppm or less.
Actually, it is difficult to make it completely anhydrous, and 1 ppm or more is included.

<Viscosity of electrolyte>
The viscosity of the electrolytic solution of the present invention is not particularly limited. In addition, 10-0.1 mPa * s is preferable in 25 degreeC, and 5-0.5 mPa * s is more preferable.

  The viscosity of the electrolytic solution is measured using a 1 mL sample placed in a rheometer (for example, CLS 500 manufactured by TA Instruments) and a Steel Cone (for example, manufactured by TA Instruments) having a diameter of 4 cm / 2 °. The sample is kept warm in advance until the temperature becomes constant at the measurement start temperature, and the measurement starts thereafter. The measurement temperature is 25 ° C.

<Applications of electrolyte>
The electrolyte of the present invention, particularly the non-aqueous electrolyte, includes, for example, an electrolytic capacitor, an electrochemical capacitor (electric double layer capacitor), a battery charged / discharged by charge transfer of ions, a solid display element such as electroluminescence, a current It can be used favorably for sensors such as sensors and gas sensors.
Among these, it is preferable to use for lithium ion batteries and lithium ion capacitors.

[Lithium ion battery]
The electrolytic solution containing the compound represented by the general formula (I) of the present invention is preferably used for a lithium ion battery, and particularly preferably used for a non-aqueous secondary battery.
Hereinafter, although a lithium ion battery is demonstrated about a typical lithium ion secondary battery, it is not limited to a secondary battery.
The lithium ion battery of the present invention uses the above-described non-aqueous electrolyte of the present invention.
As a preferred embodiment of a non-aqueous secondary battery, a lithium ion secondary battery will be described with reference to FIG.
The lithium ion secondary battery 10 of the present 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 (a negative electrode current collector 3 and a negative electrode active material layer 4) capable of inserting and releasing lithium ions or dissolving and depositing lithium ions. In addition to these members, the separator 9 disposed between the positive electrode and the negative electrode, a current collecting terminal (not shown), an outer case, etc. ). 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, lithium ion exchanges a and b are generated in the electrolytic solution 5, charging α and discharging β can be performed, and operation or storage via the operation mechanism 6 via the circuit wiring 7. It can be performed. Hereinafter, the configuration of a lithium ion secondary battery which is a preferred embodiment of the present invention will be described in more detail.

(Battery shape)
The battery shape to which the lithium ion secondary battery of this 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, it may be of a different shape such as a horseshoe shape or a comb shape considering the shape of the system or device to be incorporated. Among them, from the viewpoint of efficiently releasing the heat inside the battery to the outside, a square shape such as a bottomed square 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 and discharging efficiently escapes 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 is 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.

In the bottomed square shape, the ratio of the area S of the largest surface (the product of the width and height of the outer dimensions excluding the terminal portion, unit cm ² ) to the thickness T (unit cm) of the battery outer shape The 2S / T value is preferably 100 or more, and more preferably 200 or more. By increasing the maximum surface, it is possible to improve characteristics such as cycleability and high-temperature storage even for high-power and large-capacity batteries, as well as increase the heat dissipation efficiency during heat generation. Can be suppressed.

(Members constituting the battery)
The lithium ion secondary battery of the present embodiment is configured by including an electrolytic solution 5, positive and negative electrode electrode mixtures C and A, and a separator basic member 9, based on FIG. 1. Hereinafter, each of these members will be described.

(Electrode mixture)
The electrode mixture is obtained by applying a dispersion of an active material and a conductive agent, a binder, a filler, etc. on a current collector (electrode substrate). In a lithium ion battery, preferably a lithium ion secondary battery It is preferable to use a positive electrode mixture in which 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, each component in the dispersion (electrode composition) constituting the electrode mixture will be described.

-Positive electrode active material It is preferable to use a transition metal oxide for the positive electrode active material, and in particular, it has a transition element M ^a (one or more elements selected from Co, Ni, Fe, Mn, Cu, V). Is preferred. Further, mixed element M ^b (elements of the first (Ia) group of the metal periodic table other than lithium, elements of the second (IIa) group, Al, Ga, In, Ge, Sn, Pb, Sb, Bi, Si , P, B, etc.) may be mixed. As such transition metal oxides, for example, specific transition metal oxides including those represented by any of the following formulas (MA) to (MC), or other transition metal oxides such as V ₂ O ₅ , MnO ₂ Etc. As the positive electrode active material, a particulate positive electrode active material may be used. Specifically, a transition metal oxide capable of reversibly inserting and releasing lithium ions can be used, but the above-described specific transition metal oxide is preferably used.

The transition metal oxides, oxides containing the above transition element M ^a is preferably exemplified. At this time, a mixed element M ^b (preferably Al) or the like may be mixed. The mixing amount is preferably 0 to 30 mol% with respect to the amount of the transition metal. Moreover, those the molar ratio of Li / ^{M a} is synthesized by mixing so that 0.3 to 2.2 is more preferable.

[Transition metal oxide represented by formula (MA) (layered rock salt structure)]
Among the lithium-containing transition metal oxides, those represented by the following general formula are preferable.

Li _aa M ¹ O _bb ··· general formula (MA)

In formula (MA), ^{M 1} are as defined above ^{M a,} and the preferred range is also the same. aa represents 0 to 1.2, preferably 0.1 to 1.15, and more preferably 0.6 to 1.1. bb represents 1-3 and 2 is preferable. A part of M ¹ may be substituted with the mixed element M ^b . The transition metal oxide represented by the general formula (MA) typically has a layered rock salt structure.

  The transition metal oxide is more preferably represented by the following formulas.

The general formula _{(MA-1) Li g CoO} k
The general formula _{(MA-2) Li g NiO} k
The general formula _{(MA-3) Li g MnO} k
Formula _{(MA-4) Li g Co} j Ni 1-j O k
Formula _{(MA-5) Li g Ni} j Mn 1-j O k
Formula _{(MA-6) Li g Co} j Ni i Al 1-j-i O k
Formula _{(MA-7) Li g Co} j Ni i Mn 1-j-i O k

In general formulas (MA-1) to (MA-7), g has the same meaning as the above aa, and the preferred range is also the same. j represents 0.1 to 0.9. i represents 0 to 1; However, 1-j-i is 0 or more. k has the same meaning as the above bb, and the preferred range is also the same.
Specific examples of the transition metal compounds represented by the general formulas (MA-1) to (MA-7) include LiCoO ₂ (lithium cobaltate [LCO]), LiNi ₂ O ₂ (lithium nickelate) LiNi _0.85. Co _0.01 Al _0.05 O ₂ (nickel cobalt lithium aluminum oxide [NCA]), LiNi _0.33 Co _0.33 Mn _0.33 O ₂ (nickel manganese lithium cobalt oxide [NMC]), LiNi _0.5 Mn _0.5 O ₂ (lithium manganese nickelate) can be mentioned.

  The transition metal oxide represented by the general formula (MA) partially overlaps, but when represented by changing the notation, the following are also preferable examples.

_{(I) Li g Ni x Mn} y Co z O 2 (x> 0.2, y> 0.2, z ≧ 0, x + y + z = 1)

Representative:
_{Li g Ni 1/3 Mn 1/3 Co 1/3} O 2
Li _g Ni _1/2 Mn _1/2 O ₂

_{(Ii) Li g Ni x Co} y Al z O 2 (x> 0.7, y>0.1,0.1> z ≧ 0.05, x + y + z = 1)

Representative:
_{Li g Ni 0.8 Co 0.15 Al 0.05} O 2

[Transition metal oxide represented by general formula (MB) (spinel structure)]
As the lithium-containing transition metal oxide, those represented by the following general formula (MB) are particularly preferable.

Li _c M ² ₂ O _d General formula (MB)

In formula (MB), ^{M 2} are as defined above ^{M a,} and the preferred range is also the same. c represents 0 to 2, preferably 0.1 to 1.15, and more preferably 0.6 to 1.5. d represents 3-5, and 4 is preferable.

  The transition metal oxides represented by the general formula (MB) are more preferably those represented by the following general formulas.

Formula _{(MB-1) Li mm Mn} 2 O nn
Formula _{(MB-2) Li mm Mn} p Al 2-p O nn
Formula _{(MB-3) Li mm Mn} p Ni 2-p O nn

In general formulas (MB-1) to (MB-3), mm is synonymous with c, and the preferred range is also the same. nn has the same meaning as d, and the preferred range is also the same. p represents 0-2. Specific examples of the transition metal compound include LiMn ₂ O ₄ and LiMn _1.5 Ni _0.5 O ₄ .

  As transition metal oxides represented by the general formula (MB), those represented by the following are also preferred examples.

General formula (αa) LiCoMnO ₄
General formula (αb) Li ₂ FeMn ₃ O ₈
General formula (αc) Li ₂ CuMn ₃ O ₈
General formula (αd) Li ₂ CrMn ₃ O ₈
General formula (αe) Li ₂ NiMn ₃ O ₈

  Of the above, an electrode containing Ni is more preferable from the viewpoint of high capacity and high output.

[Transition metal oxide represented by the general formula (MC)]
As the lithium-containing transition metal oxide, it is also preferable to use a lithium-containing transition metal phosphate, and among them, those represented by the following general formula (MC) are also preferable.

Li _e M ³ (PO ₄ ) _f: General formula (MC)

  In general formula (MC), e represents 0-2, 0.1-1.15 are preferable and 0.5-1.5 are more preferable. f represents 1-5, and 0.5-2 are preferable.

M ³ represents one or more elements selected from V, Ti, Cr, Mn, Fe, Co, Ni, and Cu. M ³ represents, in addition to the mixing element ^{M b} above, Ti, Cr, Zn, Zr, may be substituted by other metals such as Nb. Specific examples include, for example, olivine-type iron phosphates such as LiFePO ₄ and Li ₃ Fe ₂ (PO ₄ ) ₃ , iron pyrophosphates such as LiFeP ₂ O ₇ , cobalt phosphates such as LiCoPO ₄ , and Li _3. Monoclinic Nasicon type vanadium phosphate salts such as V ₂ (PO ₄ ) ₃ (lithium vanadium phosphate) can be mentioned.
In addition, said aa, c, g, mm, and e value showing the composition of Li are the values which change by charging / discharging, and are typically evaluated by the value of the stable state when Li is contained. In the general formulas (αa) to (αe), the composition of Li is shown as a specific value, but this also varies depending on the operation of the battery.
In particular, in the present invention, a positive electrode active material containing Ni and / or Mn atoms is preferably used, and a positive electrode active material containing both Ni and Mn atoms is more preferably used.
Specific examples of particularly preferable positive electrode active materials include the following.

LiNi _0.33 Co _0.33 Mn _0.33 O ₂
LiNi _0.6 Co _0.2 Mn _0.2 O ₂
LiNi _0.5 Co _0.3 Mn _0.2 O ₂
LiNi _0.5 Mn _0.5 O ₂
LiNi _0.5 Mn _1.5 O ₄

  Since these can be used at a high potential, the battery capacity can be increased, and even when used at a high potential, the capacity retention rate is high, which is particularly preferable.

In the present invention, it is preferable to use a positive electrode active material having a charge region capable of oxidizing an organometallic compound. Specifically, it is preferable to use a material that can maintain normal use at a positive electrode potential (Li / Li ⁺ reference) of 3.5 V or higher. The positive potential is more preferably 3.8 V or more, further preferably 3.9 V or more, and particularly preferably 4 V or more. In particular, the positive potential is preferably 4.1 V or higher, and most preferably 4.2 V or higher. The upper limit is not particularly limited. However, 5V or less is practical. By setting it as such a range, cycling characteristics and high-rate discharge characteristics can be improved.
Here, being able to maintain normal use means that the electrode material does not deteriorate and become unusable even when charged at that voltage, and this potential is also referred to as a normal usable potential.
The positive electrode potential (Li / Li ⁺ reference) at the time of charging / discharging is represented by the following formula.

    (Positive electrode potential) = (negative electrode potential) + (battery voltage)

  When lithium titanate is used as the negative electrode, the negative electrode potential is 1.55V. When graphite is used as the negative electrode, the negative electrode potential is 0.1V. The battery voltage is observed during charging and the positive electrode potential is calculated.

  The electrolytic solution (nonaqueous electrolytic solution) of the present invention is particularly preferably used in combination with a high potential positive electrode. When a positive electrode with a high potential is used, the cycle characteristics tend to be greatly reduced. However, according to a preferred embodiment of the present invention, the nonaqueous electrolyte can maintain good performance with this decrease suppressed. .

In the lithium ion battery of the present invention, preferably a lithium non-aqueous secondary battery, the average particle size of the positive electrode active material used is not particularly limited, but is preferably 0.1 μm to 50 μm. No particular limitation is imposed on the specific surface area, preferably from 0.01m ² / g~50m ² / g by the BET method. Further, the pH of the supernatant 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.

  To make the positive electrode active material 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. You may use the positive electrode active material obtained by the baking method, after wash | cleaning with water, acidic aqueous solution, alkaline aqueous solution, and an organic solvent.

  Although the compounding quantity of a positive electrode active material is not specifically limited, 60-98 mass% is preferable in a solid component 100 mass% in the dispersion (mixture) for comprising an active material layer, and 70-95 mass% is more. preferable.

-Negative electrode active material As a negative electrode active material, what can insert and discharge | release lithium ion reversibly is preferable. There is no particular limitation as long as these conditions are satisfied. Examples thereof include carbonaceous materials, metal oxides such as tin oxide and silicon oxide, metal composite oxides, lithium alloys such as lithium alone and lithium aluminum alloys, and metals capable of forming an alloy with lithium such as Sn or Si.

These may be used alone or in any combination of two or more, and the ratio in this case may be any ratio. Among these, a carbonaceous material or a lithium composite oxide is preferable from the viewpoint of reliability.
The metal composite oxide is preferably one that can occlude and release lithium, and 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 firing artificial graphite such as petroleum pitch, natural graphite, and vapor-grown graphite, and various synthetic resins such as PAN-based resins and furfuryl alcohol resins. Furthermore, 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, mesophase micro Examples thereof include spheres, graphite whiskers, and flat graphite.

  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 may have an interplanar spacing, density, and crystallite size as described in JP-A-62-222066, JP-A-2-6856, and 3-45473. preferable. 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, and the like. It can also be used.

  It is preferable that the metal oxide and metal composite oxide which are negative electrode active materials used in the lithium ion battery of the present invention, preferably a lithium non-aqueous secondary battery, contain at least one of them. Among these metal oxides and metal composite oxides, amorphous oxides are preferable, and chalcogenite, 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 the region of 20 ° to 40 ° in terms of 2θ values, and is a crystalline diffraction line. You may have. The strongest intensity of the 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 °. Is preferably 5 times or less, and particularly preferably has no crystalline diffraction line.

Among the group of compounds consisting of the above amorphous oxide and chalcogenide, the amorphous oxide and chalcogenide of the semimetal element are more preferable, and the elements of Groups 13 (IIIB) to 15 (VB) of the periodic table, Al , Ga, Si, Sn, Ge, Pb, Sb, Bi alone or in combination of two or more thereof, and chalcogenide are particularly preferable. 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 .

  The average particle size of the negative electrode active material 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 above firing method can be calculated from an inductively coupled plasma (ICP) emission spectroscopic analysis method as a measurement method, and from a mass difference between powders before and after firing as a simple method.

  The negative electrode active material that can be used in combination with the amorphous oxide negative electrode active material centering on Sn, Si, and Ge includes carbon materials that can occlude and release lithium ions or lithium metal, lithium, lithium alloy, lithium, and the like. An alloyable metal is preferable.

The electrolytic solution of the present invention is preferably combined with a high potential negative electrode (preferably lithium / titanium oxide, a potential of 1.55 V vs. Li metal) and a low potential negative electrode (preferably a carbon material, a silicon-containing material, Excellent characteristics are exhibited in any combination with a potential of about 0.1 V vs. Li metal. Further, metal or metal oxide negative electrodes (preferably Si, Si oxide, Si / Si oxide, Sn, Sn oxide, SnB _x P _y O _z , Cu, which can be alloyed with lithium, which are being developed for higher capacity) / Sn and a plurality of these composites), and a battery using a composite of these metals or metal oxides and a carbon material as a negative electrode.
In the present invention, it is particularly preferable to use a negative electrode active material containing at least one selected from carbon, silicon (Si), titanium, and tin.

  The nonaqueous electrolytic solution of the present invention is particularly preferably used in combination with a high potential negative electrode. The high potential negative electrode is often used in combination with the above high potential positive electrode, and can suitably cope with large capacity charge / discharge.

-Conductive material The conductive material is preferably an electron conductive material that does not cause a chemical change in a configured lithium ion battery, preferably a lithium ion secondary battery, and a known conductive material can be arbitrarily 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- , Etc.), etc.), metal fibers or polyphenylene derivatives (described in JP-A-59-20,971) can be contained as one kind or a mixture thereof. Among these, the combined use of graphite and acetylene black is particularly preferable. 11-50 mass% is preferable and, as for the addition amount of the said electrically conductive agent, 2-30 mass% is more preferable. In the case of carbon or graphite, 2 to 15% by mass is particularly preferable.

-Binder Examples of the binder include polysaccharides, thermoplastic resins, and polymers having rubber elasticity. Among these, for example, starch, carboxymethyl cellulose, cellulose, diacetyl cellulose, methyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, sodium alginate, polyacrylic acid, sodium polyacrylate, polyvinyl phenol, polyvinyl methyl ether, polyvinyl alcohol, polyvinyl pyrrolidone, Water-soluble polymers such as polyacrylonitrile, polyacrylamide, polyhydroxy (meth) acrylate, styrene-maleic acid copolymer, polyvinyl chloride, polytetrafluoroethylene, polyvinylidene fluoride, tetrafluoroethylene-hexafluoropropylene copolymer, vinylidene Fluoride-tetrafluoroethylene-hexafluoropropylene copolymer, polyethylene (Meth) acrylic acid ester copolymer containing (meth) acrylic acid ester such as polypropylene, ethylene-propylene-diene polymer (EPDM), sulfonated EPDM, polyvinyl acetal resin, methyl methacrylate, 2-ethylhexyl acrylate, ( (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, fluororubber, polyethylene oxide , Polyester polyurethane resin, polyether polyurethane resin, polycarbonate polyurethane resin, polyester resin, phenol resin, epoxy resin emulsion (late Box) or suspension is preferred, latex 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. If the amount 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 compound material may contain the filler. The material forming the filler is preferably a fibrous material that does not cause a chemical change in the non-aqueous secondary battery of the present invention. 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 in a dispersion.

-Current collector As the positive / negative current collector, an electron conductor that does not cause a chemical change is preferably 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, aluminum, copper, stainless steel, nickel, and titanium are preferable, and aluminum, copper, and a copper alloy are more preferable.

As the shape of the current collector, a film sheet is usually used, but a net, a punched one, 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. In addition, 1 micrometer-500 micrometers are preferable. Moreover, it is also preferable that the current collector surface is roughened by surface treatment.
An electrode mixture of a lithium ion battery (preferably a lithium ion secondary battery) is formed by a member appropriately selected from these materials.

(Separator)
The separator used in the lithium ion battery of the present invention (preferably a lithium ion secondary battery or a lithium non-aqueous secondary battery) has a mechanical strength that electrically insulates the positive electrode and the negative electrode, ion permeability, and a positive electrode and a negative electrode. It is preferable that the contact surface is made of a material having oxidation / reduction resistance. 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 shut-down function for ensuring reliability, that is, a function of closing a gap at 80 ° C. or higher to increase resistance and interrupting current, and the plugging temperature is preferably 90 ° C. or higher and 180 ° C. or lower. .

  The shape of the holes of the separator is usually circular or elliptical, and the size is preferably 0.05 μm to 30 μm, more 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 preferably 20% to 90%, and more preferably 35% to 80%.

  As said polymer material, the thing using a single material, such as a cellulose nonwoven fabric, polyethylene, a polypropylene, or a composite material of 2 or more types may be used. What laminated | stacked the 2 or more types of microporous film which changed the hole diameter, the porosity, the obstruction | occlusion temperature of a hole, etc. 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 such an independent thin film shape, a separator formed by forming a composite porous layer containing inorganic particles 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.

(Production of lithium ion battery)
As described above, the shape of the lithium ion battery (preferably a lithium ion secondary battery or a lithium non-aqueous secondary battery) of the present invention 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 a typical bottomed cylindrical lithium secondary battery 100 of a lithium ion battery 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 and discharging efficiently escapes 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. In addition, in the figure, 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 interruption 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 is mixed with a binder or filler used as desired 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 composite material 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 the present embodiment, a cylindrical battery is taken as an example, but the present invention is not limited to this. For example, the positive and negative electrode sheets produced by the above method are overlapped with a separator and then processed into a sheet battery as it is, or after being folded and inserted into a rectangular can, the can and the sheet After the electrical connection, the electrolyte may be injected, and the opening may be sealed using a sealing plate to produce a square battery.

  In any embodiment, the safety valve can be used as a sealing plate for sealing the opening. In addition to the safety valve, the sealing member 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 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 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, can, sheet, and lead plate, a known method (for example, direct current or alternating current electric welding, laser welding, or ultrasonic welding) can be used. As the sealing agent for sealing, a conventionally known compound or mixture such as asphalt can be used.

[Uses of lithium-ion batteries]

  A lithium ion battery, preferably a lithium secondary battery, includes a secondary battery (lithium ion secondary battery) that uses insertion and extraction of lithium in a charge / discharge reaction, and a secondary battery (lithium ion) that uses precipitation and dissolution of lithium. Metal secondary battery). In the present invention, application as a lithium ion secondary battery is preferable.

  The lithium ion battery of the present invention may be primary or secondary, but is preferably a non-aqueous secondary battery and can be applied to various applications. Although there is no particular limitation on the application mode, for example, when installed in an electronic device, a notebook computer, a pen input personal computer, a mobile personal computer, an electronic book player, a mobile phone, a cordless phone, a pager, a handy terminal, a mobile fax machine, a mobile phone Copy, portable printer, headphone stereo, video movie, LCD TV, handy cleaner, portable CD, minidisc, electric shaver, transceiver, electronic notebook, calculator, memory card, portable tape recorder, radio, backup power supply, memory card, etc. It is done. 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 purposes and space. Moreover, it can also combine with a solar cell.

  Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not construed as being limited thereto. Unless otherwise specified, parts and% are based on mass.

Example 1
An electrolyte solution was prepared as follows.

(1) Preparation of electrolyte solution Ethylene carbonate and ethyl methyl carbonate were mixed at a volume ratio of 1: 2.
To this mixed solution, the compound represented by the general formula (I) of the present invention, the compound of the reference example or the comparative compound was added in the addition amount shown in the following Table 1, and the electrolyte solutions 101 and 102 of the reference example and the present invention were added. Electrolytic solutions 103 to 110 and comparative electrolytic solutions c01 to c03 were prepared.

  The compounds used are shown below.

  The penetration rate of the electrolytic solution into the negative electrode of each prepared electrolytic solution was measured as follows.

(2) Production of negative electrode for evaluation of penetration rate A negative electrode produced with 85 parts by mass of graphite, 7.5 parts by mass of carbon black and 7.5 parts by mass of polyvinylidene fluoride was applied to one side on a copper foil having a thickness of 20 μm and dried. Then, after making it 120 micrometers in thickness with a press machine, it cut | divided into 1 cm x 4 cm strip shape, and was set as the negative electrode for evaluation.

(3) Evaluation of penetration rate As shown in FIG. 3, the negative electrode for evaluation was immersed in an electrolyte solution by 1 cm from the lower end, and the time for which the electrolyte solution soaked up to a length of 1.5 cm from the electrolyte solution surface was visually measured.
Note that the portion soaked with the electrolytic solution is wet with the electrolytic solution, so that the portion soaked can be easily identified.
The obtained results are summarized in Table 1 below.

From Table 1 above, the electrolytic solution c01 in which the compound represented by the general formula (I) of the present invention is not added to the electrolytic solution is 110 seconds, whereas it is represented by the general formula (I) of the present invention. The electrolytic solution to which the compound was added was 85 to 93 seconds, and the time required for soaking was shortened by 25 to 17 seconds.
Moreover, it can be seen that the compound represented by the general formula (I) of the present invention exhibits an effect with a very small addition amount of 0.3 to 1.2% by mass with respect to the electrolytic solution.
On the other hand, in the comparative compound, the time required for soaking was not shortened, or conversely, it was delayed by 2 seconds.

Example 2
Using each electrolytic solution prepared above, a 2032 type coin battery was produced.

-Preparation of 2032 type coin battery The positive electrode is composed of 85% by mass of an active material: lithium manganate (LiMn ₂ O ₄ ), 7% by mass of conductive assistant: carbon black, binder: 8% by mass of PVDF (polyvinylidene fluoride). It was produced with.
A negative electrode was produced with a composition of 92% by mass of active material: Gr (natural graphite) and 8% by mass of binder: PVDF.
As the separator, a polypropylene separator having a thickness of 25 μm was prepared.
Using the above-described positive and negative electrodes and separator, and using the prepared electrolytes 101 to 110 and c01 to c03, 2032 type coin batteries 201 to 210 of the present invention and 2032 type coin batteries c11 to c13 of comparative examples were produced. .

  About each produced battery, the capacity | capacitance maintenance factor after 300 cycles was evaluated as follows.

<Discharge capacity maintenance rate-300 cycles>
Using each 2032 type coin battery that was manufactured, in a constant temperature bath at 60 ° C., a constant current of 1 C was charged until the battery voltage reached 4.15 V at 4.0 mA, and then the current value at a constant voltage of 4.15 V. Until 0.02 mA. However, the upper limit of the charging time was 2 hours. Next, constant current discharge at 1 C was performed until the battery voltage became 2.75 V at 4.0 mA. This was one cycle. This was repeated until 300 cycles were reached, and the discharge capacity (mAh) at the 300th cycle was measured.
Based on the obtained value, the discharge capacity retention rate (%) was calculated based on the following formula.

Discharge capacity maintenance rate (%) =
(Discharge capacity at the 300th cycle / discharge capacity at the first cycle) × 100

The results obtained are summarized in Table 2 below.
In Table 2, electrolyte No. Instead, the compound or comparative compound number represented by the general formula (I) of the present invention and the addition amount thereof in each electrolytic solution are shown.

As a result, the batteries 20 3 to 210 using the electrolytic solution of the present invention had a higher discharge capacity maintenance rate than the batteries c 11 to c 13 using the comparative electrolytic solution because the polyvalent ester compound was added. .

  From the results of Examples 1 and 2, it can be seen that the electrolytic solution containing the compound represented by the general formula (I) of the present invention exhibits excellent electrical characteristics in lithium ion batteries and lithium ion capacitors.

  While this invention has been described in conjunction with its embodiments, we do not intend to limit our invention in any detail of the description unless otherwise specified and are contrary to the spirit and scope of the invention as set forth in the appended claims. I think it should be interpreted widely.

  This application claims the priority based on Japanese Patent Application No. 2014-242392 for which it applied for a patent in Japan on November 28, 2014, and this is referred to here for the contents of this specification. Capture as part.

C positive electrode (positive electrode composite)
1 Positive electrode conductive material (current collector)
2 Positive electrode active material layer A Negative electrode (negative electrode composite)
3 Negative electrode conductive material (current collector)
4 Negative electrode active material layer 5 Non-aqueous electrolyte 6 Operating mechanism 7 Circuit wiring 9 Separator 10 Lithium ion secondary battery 12 Separator 14 Positive electrode sheet 16 Negative electrode sheet 18 Exterior can 20 also serving as negative electrode Insulating plate 22 Sealing plate 24 Positive electrode current collector 26 Gasket 28 Pressure-sensitive valve element 30 Current interrupting element 100 Bottomed cylindrical shape lithium secondary battery

Claims (7)

An electrolyte solution in which an electrolyte is dissolved in a non-aqueous solvent including a carbonate-based solvent, and is used in combination with a negative electrode, which contains a compound represented by the following general formula (I).
In the general formula (I), X represents a saturated hydrocarbon residue which may contain an n1 + n2 valent ether bond represented by any one of the following general formulas (x1) to (x6) . L ¹ is to display the group selected from the following formulas (a1 ') and (a2'). L ² represents a divalent linking group having at least one divalent linking group having an oxygen atom. R ¹ and R ² each independently represents an alkyl group or a cycloalkyl group. n1 represents an integer of 3 or more, and n2 represents an integer of 0 or more. When n1 is 3 or more, the plurality of -L ¹ -R ¹ may be the same or different, and when n2 is 2 or more, the plurality of -L ² -R ² may be the same or different.
In the general formulas (x1) to (x6), R ^C1 represents a hydrogen atom or an alkyl group. nc1 to nc5 each independently represents an integer of 1 to 5, and nc6 to nc10 each independently represents 0 or 1.
In the general formulas (a1 ′) and (a2 ′), * represents a bond that bonds to X.
However, when L ¹ is a group represented by the general formula (a2 ′), in the general formula (x1), nc6 is 1, and in the general formula (x2), R ^C1 is an alkyl group, or nc7 is 1.   The electrolyte solution according to claim 1, wherein the compound represented by the general formula (I) is contained in an amount of 0.001 to 20 mass% in the electrolyte solution. The electrolytic solution according to claim 1 or 2 , wherein L ² is a group selected from the following general formula (b1) and general formula (b2).
In general formulas (b1) and (b2), Lb represents a single bond, an alkylene group or a cycloalkylene group. nb represents an integer of 1 to 5. Here, * indicates a bond that bonds with X. The electrolytic solution according to any one of claims 1 to 3 , wherein the n2 is 0. The electrolyte solution according to any one of claims 1 to 4 , wherein the compound represented by the general formula (I) has a molecular weight of 100 to 2,000. The lithium ion battery using the electrolyte solution of any one of Claims 1-5 . The lithium ion capacitor using the electrolyte solution of any one of Claims 1-5 .