JP6520151B2 - Nonaqueous Electrolyte and Nonaqueous Electrolyte Secondary Battery - Google Patents

Description

The present invention is a nonaqueous electrolyte solution, and to a nonaqueous electrolyte secondary battery, particularly, a LiPF ₆ as an electrolyte, and a lithium oxalate salt, the nonaqueous electrolytic solution in combination with carboxylic acid anhydride in a specific ratio, The present invention also relates to a non-aqueous electrolyte secondary battery using the non-aqueous electrolyte.

  Non-aqueous electrolyte secondary batteries such as lithium secondary batteries are being put to practical use in a wide range of applications such as so-called commercial power supplies such as mobile phones and notebook personal computers, automotive power supplies for driving such as automobiles and large power supplies for stationary. is there. However, the demand for higher performance for non-aqueous electrolyte secondary batteries in recent years is increasing, and battery characteristics such as high capacity, high output, storage capacity, storage capacity, resistance after cycle, capacity after cycle, resistance after cycle It is required to achieve various characteristics such as

  In particular, when using a lithium secondary battery as a stationary large power source for power sources for electric vehicles, various backup applications, load leveling applications for power supply, output stabilization applications for natural energy generation, etc., these are used outdoors. Because it may be used, there is little deterioration in its capacity even when repeatedly charged and discharged in a high temperature environment, little deterioration in charge / discharge rate characteristics, little deterioration in input / output characteristics (or an increase in internal impedance) Needs to meet the requirements.

Moreover, in such a large-sized battery, not only the size of the unit cell is increased, but also a large number of unit cells are connected in series and parallel. For this reason, there are problems with reliability and safety due to various non-uniformities such as variations in discharge characteristics of individual cells, variations in temperature among single cells, and variations in capacity and state of charge of individual cells. Is likely to occur. If the battery design or management is inadequate, only a part of the cells constituting the battery assembly as described above may be kept in a high charge state, or the temperature inside the battery may rise to a high temperature state. Cause such problems.
That is, the current non-aqueous electrolyte secondary battery has a high capacity retention ratio after a durability test such as a high temperature storage test or a cycle test, and is excellent in charge / discharge rate characteristics, input / output characteristics, impedance characteristics, etc. Items are required at extremely high levels.
Until now, as a means for improving high-temperature storage tests and cycle tests of non-aqueous electrolyte secondary batteries, a large number of various battery components including active materials of positive and negative electrodes and non-aqueous electrolytes Technology is being considered.

  Patent Document 1 discloses the formation of at least one film selected from the group consisting of a specific positive electrode active material, a lithium salt having an oxalate complex as an anion, vinylene carbonate, vinyl ethylene carbonate, ethylene sulfite, and fluoro ethylene carbonate. The technique which can prevent that the various characteristics of a non-aqueous electrolyte solution secondary battery fall when it preserve | saves in a high temperature environment is disclosed by using the non-aqueous electrolyte solution which added the agent.

  Further, Patent Document 2 discloses a non-aqueous electrolytic solution secondary battery in which an acid anhydride is added as a film forming agent to a non-aqueous electrolytic solution secondary battery using a graphite-based negative electrode. By containing an acid anhydride as a film formation agent, it is estimated that the excessive decomposition | disassembly of the electrolyte solution in a charging / discharging process is suppressed, and a cycle characteristic improves.

Further, in Patent Document 3, the electrolyte contains a solvent containing propylene carbonate, succinic anhydride, and at least one of lithium difluoro (oxalate) borate and lithium bis oxalate borate, and the content of propylene carbonate is Nonaqueous electrolyte characterized in that it is 60% by volume, and the total mass of the lithium difluoro (oxalate) borate and the lithium bis oxalate borate is 10% to 60% with respect to the mass of the succinic anhydride. A battery is disclosed. In Patent Document 2, at least one of succinic anhydride, lithium difluoro oxalate borate and lithium bis (oxalate) borate is used in Patent Document 2 because the resistance of the film formed by the acid anhydride is high and sufficient cycle characteristics can not be obtained. The cycle characteristics can be improved by reducing the film resistance derived from succinic anhydride by using a non-aqueous electrolytic solution containing
In addition, Non-Patent Document 1 mentions the structure of a film formed by lithium bis (oxalate) borate on the negative electrode surface of a non-aqueous electrolyte secondary battery. According to Non-Patent Document 1, the lithium oxalate salt is such that the bond between an atom having a formal negative charge and a ligand (that is, an oxalate skeleton) bound thereto is cleaved by electrochemical reduction, and another molecule is produced. It has been reported to recombine with.

Unexamined-Japanese-Patent No. 2006-196250 Unexamined-Japanese-Patent No. 2000-298859 JP, 2009-123605, A

Wu et al. , Electrochemical and Solid-State Lett. 6, A144 (2003).

However, in these techniques, the capacity retention rate, charge / discharge rate characteristics, input / output retention rate at the time of high temperature storage endurance and high temperature cycle are insufficient, and further improvement of the properties has been desired.
The object of the present invention is to solve the above-mentioned problems and to have a high capacity retention ratio after endurance test such as high temperature storage test and cycle test, and excellent charge / discharge rate characteristics, input / output characteristics, impedance characteristics etc even after endurance test. Another object of the present invention is to provide a non-aqueous electrolytic solution capable of providing a non-aqueous electrolytic solution secondary battery, and to provide a non-aqueous electrolytic solution secondary battery using the non-aqueous electrolytic solution.

As a result of intensive studies to solve the above problems, the present inventors set the mass ratio of LiPF ₆ in a non-aqueous electrolyte, lithium oxalate salt, and carboxylic anhydride as a specific ratio range. Thus, a non-aqueous electrolytic solution secondary battery excellent in charge / discharge rate characteristics, input / output characteristics, impedance characteristics, etc. even after the endurance test by having a high capacity retention after a durability test such as a high temperature storage test or a cycle test It has been found that a non-aqueous electrolytic solution that can be realized can be realized, and the present invention has been completed.
That is, the present invention relates to the following non-aqueous electrolytic solution and non-aqueous electrolytic solution secondary battery.
[1]
A non-aqueous electrolytic solution comprising a non-aqueous solvent, LiPF ₆ , lithium oxalate salt, and a compound represented by the following general formula (1), wherein the mass% of LiPF ₆ with respect to the entire non-aqueous electrolytic solution is [A], When the mass% of the lithium oxalate salt is [B] and the mass% of the compound represented by the following general formula (1) is [C],
(A) [A] / [B] is 5 or more and 90 or less (b) [B] ≧ [C] and [B] + [C] <2.0 mass%
Non-aqueous electrolyte that meets

(In the general formula (1), R ¹ and R ² each independently may have a substituent and represent a hydrocarbon group having a carbon number of 15 or less. R ¹ and R ² are bonded to each other And may form an annular structure)
[2]
The non-aqueous electrolytic solution according to [1], wherein the compound represented by the general formula (1) is combined with R ¹ and R ² to form a cyclic structure.
[3]
The non-aqueous electrolytic solution as described in [1], wherein the compound represented by the general formula (1) is a chain compound.
[4]
Lithium oxalate salt is a group consisting of lithium bis (oxalate) borate, lithium difluoro (oxalate) borate, lithium tris (oxalate) phosphate, lithium difluoro bis (oxalate) phosphate, lithium tetrafluoro (oxalate) phosphate The nonaqueous electrolytic solution according to any one of [1] to [3], which is at least one or more kinds.
[5]
A non-aqueous electrolyte secondary battery comprising a negative electrode and a positive electrode capable of storing and releasing lithium ions, and the non-aqueous electrolyte according to any one of [1] to [4].
[6]
The negative electrode has a negative electrode active material layer on a current collector, and the negative electrode active material layer is a single metal, an alloy and a compound of silicon, a single metal, an alloy and a compound of tin, a carbonaceous material, and a lithium titanium composite The non-aqueous electrolyte solution secondary battery as described in [5] which contains the negative electrode active material containing at least 1 sort (s) of oxides.
[7]
The positive electrode has a positive electrode active material layer on a current collector, and the positive electrode active material layer is a lithium-cobalt composite oxide, a lithium-cobalt-nickel composite oxide, a lithium-manganese composite oxide, lithium-cobalt · Characterized in that it contains at least one selected from the group consisting of a manganese composite oxide, a lithium-nickel composite oxide, a lithium-nickel-manganese composite oxide, and a lithium-cobalt-nickel-manganese composite oxide [ 5] or the non-aqueous electrolyte secondary battery as described in [6].
[8]
The positive electrode has a positive electrode active material layer on a current collector, and the positive electrode active material layer is selected from the group consisting of LixMPO ₄ (M = transition metal of Groups 4 to 11 of the fourth period of the periodic table) The nonaqueous electrolyte secondary battery according to any one of [5] to [7], wherein x contains 0 <x <1.2).

The present invention is characterized in that the composition represented by LiPF ₆ and lithium oxalate salt and the compound represented by the general formula (1) is in a specific composition range.
The inventor has intensively developed a novel electrolytic solution composition by mixing a compound represented by the general formula (1) with a lithium oxalate salt. As a result, it was found that when the amount of lithium oxalate salt is equal to or more than the amount of the compound represented by the general formula (1), a film having high durability and low resistance is formed.

This is because when the amount of lithium oxalate salt is equal to or more than the amount of the compound represented by the general formula (1), a bond with the lithium oxalate salt is appropriately formed, but the amount of lithium oxalate salt is a general formula If the amount is less than the amount of the compound represented by (1), the reaction with the solvent other than the lithium oxalate salt is increased without appropriately forming a bond with the lithium oxalate salt, the durability is improved. It is presumed that a low and high resistance film is formed. Furthermore, the inventor further pays attention to the amount of LiPF ₆ contained in the non-aqueous electrolyte solution, and efficiently introduces a fluorine atom into the film by setting it as the composition of the specific LiPF ₆ and lithium oxalate salt. It has been found that it is possible to improve the durability of the film and to reduce the resistance.
Thus, by using the non-aqueous electrolyte solution of the present invention, the capacity retention ratio is high, and the charge / discharge rate characteristics and the input / output performance are excellent even after the endurance test such as the high temperature storage test and the cycle test. It is possible to provide an excellent non-aqueous electrolyte battery.

  Hereinafter, the embodiment of the present invention will be described in detail, but the description of the constituent requirements described below is an example (representative example) of the embodiment of the present invention, and the present invention exceeds the gist of the claims. There is no limitation to these contents unless otherwise stated.

<1. Electrolyte>
<1-1. Electrolyte>
<1-1-1. LiPF ₆ >
The present invention contains LiPF ₆ as an electrolyte.

In the non-aqueous electrolyte solution of the present invention, the content of LiPF ₆ in the non-aqueous electrolyte solution is not limited as long as the effects of the present invention are not significantly impaired, but is usually 8% by mass or more and 9% by mass or more Is preferably 10% by mass or more. Moreover, it is 18 mass% or less normally, It is preferable that it is 16 mass% or less, It is more preferable that it is 15 mass% or less. When the concentration of LiPF ₆ is within the above range, the balance between the lithium ion concentration in the non-aqueous electrolytic solution and the viscosity of the electrolytic solution is optimized, and high charge / discharge rate characteristics, high input / output characteristics, and high cycle durability are more achieved. It becomes easy to express. In addition, although the said value may be calculated from the preparation amount at the time of preparing a non-aqueous electrolyte solution, an electrolyte solution may be analyzed and you may calculate suitably from content contained in electrolyte solution.

<1-1-2. Lithium oxalate salt>
The present invention contains a lithium oxalate salt as an electrolyte. Examples of lithium oxalate salts include lithium difluoro (oxalate) borate, lithium bis (oxalate) borate, lithium tetrafluoro (oxalate) phosphate, lithium difluoro bis (oxalate) phosphate, lithium tris (oxalate) phosphate and the like .
Among them, lithium bis (oxalate) borate and lithium difluorobis (oxalate) phosphate are preferable because they have a high effect of improving the durability when used in combination with the compound represented by the general formula (1).

In the non-aqueous electrolytic solution of the present invention, the content of the lithium oxalate salt in the non-aqueous electrolytic solution is not limited as long as the effects of the present invention are not significantly impaired, but usually 0.0010 mass% or more, preferably 0. It is at least 01% by mass, more preferably at least 0.05% by mass, still more preferably at least 0.1% by mass, most preferably at least 0.2% by mass, and usually at most 1.8% by mass, preferably 1 .7% by mass or less, more preferably 1.6% by mass or less, particularly preferably 1.5% by mass or less. When the concentration of the lithium oxalate salt is in the above range, the effect of improving the durability such as high-temperature storage characteristics and cycle characteristics can be more easily exhibited. In addition, although the said value may be calculated from the preparation amount at the time of preparing a non-aqueous electrolyte solution, an electrolyte solution may be analyzed and you may calculate suitably from content contained in electrolyte solution.

<1-1-3. LiPF6 and lithium oxalate salts>
In the present invention, the ratio [A] / [B] of mass% [A] of LiPF ₆ to mass% [B] of lithium oxalate salt with respect to the whole non-aqueous electrolytic solution is 5 or more and 90 or less.
[A] / [B] is preferably 7 or more, more preferably 7.5 or more, still more preferably 8 or more, still more preferably 9 or more, most preferably, in order to exert the effects of the present invention more significantly. Is 10 or more, preferably 70 or less, more preferably 60 or less, and still more preferably 50 or less. When the ratio of [A] / [B] is in the above range, film formation by the lithium oxalate salt and the compound represented by the general formula (1) is promoted, and the durability is improved.

  When [A] / [B] is in the above range, the electric conductivity of the electrolytic solution is in the appropriate range, and the input / output characteristics and the charge / discharge rate characteristics are improved. Moreover, since the fluorine atom can be efficiently introduced into the film, the durability of the film can be improved and the resistance can be reduced.

<1-1-4. Other lithium salts>
Nonaqueous electrolytic solution in the present invention, as the electrolyte, although LiPF ₆ and lithium oxalate salt is used, it is possible to further contain other lithium salt one or more. As other lithium salts, lithium salts other than LiPF ₆ and lithium oxalate salts are not particularly limited as long as they are known to be used for this application, and specifically the following It can be mentioned.

For example, inorganic lithium salts such as LiBF ₄ , LiClO ₄ , LiAlF ₄ , LiSbF ₆ , LiTaF ₆ , LiWF _{7 and the} like;
Lithium fluorophosphate salts other than LiPF ₆ such as LiPO ₃ F, LiPO ₂ F ₂ ;
Lithium tungstate salts such as LiWOF ₅ ;
HCO ₂ Li, CH ₃ CO ₂ Li, CH ₂ FCO ₂ Li, CHF ₂ CO ₂ Li, CF ₃ CO ₂ Li, CF ₃ CH ₂ CO ₂ Li, CF ₃ CF ₂ CO ₂ Li, CF ₃ CF ₂ CF ₂ Carboxylic acid lithium salts such as CO ₂ Li, CF ₃ CF ₂ CF ₂ CF ₂ CO ₂ Li;
FSO ₃ Li, CH ₃ SO ₃ Li, CH ₂ FSO ₃ Li, CHF ₂ SO ₃ Li, CF ₃ SO ₃ Li, CF ₃ CF ₂ SO ₃ Li, CF ₃ CF ₂ CF ₂ SO ₃ Li, CF ₃ CF ₂ Sulfonic acid lithium salts such as CF ₂ CF ₂ SO ₃ Li;
_{LiN (FCO 2) 2, LiN} (FCO) (FSO 2), LiN (FSO 2) 2, LiN (FSO 2) (CF 3 SO 2), LiN (CF 3 SO 2) 2, LiN (C 2 F 5 Lithium imides such as SO ₂ ) ₂ , lithium cyclic 1,2-perfluoroethane disulfonyl imide, lithium cyclic 1,3-perfluoropropane disulfonyl imide, LiN (CF ₃ SO ₂ ) (C ₄ F ₉ SO ₂ ), etc. salts;
Lithium methide salts such as LiC (FSO ₂ ) ₃ , LiC (CF ₃ SO ₂ ) ₃ , LiC (C ₂ F ₅ SO ₂ ) _{3 and the} like;
In addition, LiPF ₄ (CF ₃ ) ₂ , LiPF ₄ (C ₂ F ₅ ) ₂ , LiPF ₄ (CF ₃ SO ₂ ) ₂ , LiPF ₄ (C ₂ F ₅ SO ₂ ) ₂ , LiBF ₃ CF ₃ , LiBF ₃ C _{2 F 5, LiBF 3 C 3} F 7, LiBF 2 (CF 3) 2, LiBF 2 (C 2 F 5) 2, LiBF 2 (CF 3 SO 2) 2, LiBF 2 (C 2 F 5 SO 2) 2 And fluorine-containing organic lithium salts such as

Fluorophosphate other than inorganic lithium salts and LiPF ₆ from the viewpoint of further enhancing the effect of improving input / output characteristics, charge / discharge rate charge / discharge characteristics, and impedance characteristics after durability tests such as high temperature storage tests and cycle tests obtained in the present invention. Lithium salts, sulfonic acid lithium salts, lithium imide salts, lithium oxalate salts are preferred, and lithium salts are preferred. Specifically, LiPO ₂ F ₂ , LiBF ₄ , FSO ₃ Li, LiN ( CF ₃ S
Particularly preferred is one selected from O ₂ ) ₂ and LiN (FSO ₂ ) ₂ .

The content of LiPF ₆ and other lithium salts other than lithium oxalate salts is optional as long as the effects of the present invention are not significantly impaired, but is usually 0.01% by mass or more and 0.1% by mass or more Is preferably 0.2% by mass or more. Also, it is usually 5% by mass or less, preferably 4% by mass or less, and more preferably 3% by mass or less. When the concentration of LiPF ₆ and the lithium salt other than the lithium oxalate salt is in the above range, the effect of improving charge / discharge rate characteristics, input / output characteristics, high temperature storage characteristics, cycle characteristics and the like is further easily exhibited.

In addition, LiPF ₆ and lithium oxalate salts and other lithium salts make the electric conductivity of the electrolyte a good range and ensure good battery performance, so the total mass of lithium salt in the non-aqueous electrolyte is , Usually 8.5% by mass or more, preferably 9.0% by mass or more, more preferably 9.5% by mass or more, and usually 20% by mass or less, preferably 18% by mass or less, more preferably It is preferable to use so that it becomes 17 mass% or less, More preferably, it is 16 mass% or less.

Here, the active material prepared in the electrolyte solution in the case of incorporating the LiPO ₂ F ₂ in the electrolyte solution, the LiPO ₂ F ₂ which is separately synthesized by a known method, described later method or be added to the electrolytic solution containing LiPF ₆ and in cell components of the electrode plate such as allowed to coexist water, a method of generating LiPO ₂ F ₂ in the system when the battery is assembled by using the electrolytic solution containing LiPF ₆ and the like, in the present invention Any method may be used.
There is no particular limitation on the method of measuring the content of LiPO ₂ F _{2 in} the above non-aqueous electrolyte solution and non-aqueous electrolyte battery, and any known method can be used, but it is not particularly limited. And ion chromatography, F nuclear magnetic resonance spectroscopy (hereinafter sometimes abbreviated as NMR), and the like.

The non-aqueous electrolytic solution of the present invention, as a general non-aqueous electrolytic solution, usually has, as its main component, an electrolyte and a non-aqueous solvent for dissolving the same. Furthermore, it contains at least one kind of a compound represented by the following general formula (1) (hereinafter, appropriately referred to as “specific compound”). In addition, other components (such as additives) may be contained.

（一般式（１）中、Ｒ^１，Ｒ^２はそれぞれ独立に、置換基を有していてもよく、炭素数が１以上１５以下の炭化水素基を表す。Ｒ^１，Ｒ^２とが互いに結合して、環状構造を形成していてもよい。） <1-1-5. Compound Represented by General Formula (1)>
The present invention contains, in a non-aqueous electrolytic solution, LiPF ₆ and a compound represented by the following general formula (1) together with an oxalate salt.

(In the general formula (1), R ¹ and R ² may each independently have a substituent and represent a hydrocarbon group having 1 to 15 carbon atoms. R ¹ and R ² are mutually different They may be combined to form a cyclic structure.)

The type is not particularly limited as long as R ¹ and R ² are monovalent hydrocarbon groups. For example, it may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group, or it may be a combination of an aliphatic hydrocarbon group and an aromatic hydrocarbon group. The aliphatic hydrocarbon group may be a saturated hydrocarbon group, and may contain unsaturated bonds (carbon-carbon double bonds or carbon-carbon triple bonds). The aliphatic hydrocarbon group may be linear or cyclic, and in the case of linear, it may be linear or branched. Furthermore, the chain and cyclic groups may be combined. R ¹ and R ² may be the same as or different from each other.

Further, when R ¹ and R ² bond to each other to form a cyclic structure, the hydrocarbon group formed by bonding R ¹ and R ² to each other is divalent. The type of divalent hydrocarbon group is not particularly limited. That is, it may be an aliphatic group or an aromatic group, or it may be a combination of an aliphatic group and an aromatic group. In the case of an aliphatic group, it may be a saturated or unsaturated group. Further, it may be a chain group or a cyclic group, and in the case of a chain group, it may be a linear group or a branched group. Furthermore, those in which a chain group and a cyclic group are bonded may be used.

In addition, when the hydrocarbon group of R ¹ and R ² has a substituent, the type of the substituent is not particularly limited unless it is contrary to the spirit of the present invention, and examples thereof include a fluorine atom, a chlorine atom and a bromine atom And a halogen atom such as iodine atom, preferably a fluorine atom. Moreover, as a substituent other than a halogen atom, a substituent having a functional group such as an ester group, a cyano group, a carbonyl group, an ether group and the like can also be mentioned, with preference given to a cyano group and a carbonyl group. The hydrocarbon group of R ¹ and R ² may have only one of these substituents, or may have two or more of these substituents. When they have two or more substituents, those substituents may be the same or may be different from each other.

The carbon number of each hydrocarbon group of R ¹ and R ² is not particularly limited as long as it does not contradict the spirit of the present invention, but is usually 1 or more, and usually 15 or less, preferably 12 or less, more preferably 10 More preferably, it is 9 or less. When R ¹ and R ² are bonded to each other to form a bivalent hydrocarbon group, the carbon number of the bivalent hydrocarbon group is usually 1 or more, and usually 15 or less, preferably It is 13 or less, more preferably 10 or less, still more preferably 8 or less. When the hydrocarbon group of R ¹ and R ² has a substituent containing a carbon atom, it is preferable that the total number of carbon atoms of R ¹ and R ² including the substituent satisfy the above range.

Next, specific examples of the acid anhydride represented by the above general formula (1) will be described. In the following examples, “analog” refers to an acid anhydride obtained by replacing a part of the structure of the exemplified acid anhydride with another structure without departing from the spirit of the present invention. Such as dimers, trimers and tetramers consisting of a plurality of acid anhydrides, or structurally isomeric ones having the same carbon number of substituents but having branched chains, etc., and the substituent is an acid Those having different sites of binding to an anhydride and the like can be mentioned.
First, specific examples of acid anhydrides in which R ¹ and R ² are the same are listed below.

As specific examples of acid anhydrides in which R ¹ and R ² are linear alkyl groups,
Acetic anhydride,
Propionic anhydride,
Butanoic anhydride,
2-Methylpropionic anhydride,
2,2-dimethylpropionic anhydride,
2-methylbutanoic anhydride,
3-methylbutanoic anhydride,
2,2-dimethylbutanoic anhydride,
2,3-Dimethylbutanoic anhydride,
3,3-dimethylbutanoic anhydride,
2,2,3-trimethylbutanoic anhydride,
2,3,3-trimethylbutanoic anhydride,
2,2,3,3-tetramethylbutanoic anhydride,
2-ethylbutanoic anhydride, etc.
And their analogues.

As specific examples of the acid anhydride wherein R ¹ and R ² are cyclic alkyl groups,
Cyclopropanecarboxylic acid anhydride,
Cyclopentanecarboxylic acid anhydride,
Cyclohexane carboxylic acid anhydride etc.
And their analogues.

As specific examples of the acid anhydride wherein R ¹ and R ² are alkenyl groups,
Acrylic anhydride,
2-methyl acrylic anhydride,
3-methylacrylic anhydride,
2,3-Dimethylacrylic anhydride,
3, 3-dimethyl acrylic anhydride,
2,3,3-trimethylacrylic anhydride,
2-phenylacrylic anhydride,
3-phenylacrylic anhydride,
2,3-Diphenylacrylic anhydride,
3,3-diphenylacrylic anhydride,
3-butenoic anhydride,
2-Methyl-3-butenoic anhydride,
2,2-Dimethyl-3-butenoic anhydride,
3-Methyl-3-butenoic anhydride,
2-Methyl-3-methyl-3-butenoic anhydride,
2,2-Dimethyl-3-methyl-3-butenoic anhydride,
3-pentenoic anhydride, 4-pentenoic anhydride,
2-Cyclopentenecarboxylic acid anhydride,
3-Cyclopentenecarboxylic anhydride,
4-cyclopentene carboxylic acid anhydride etc.,
And their analogues.

As specific examples of the acid anhydride wherein R ¹ and R ² are an alkynyl group,
Propynic anhydride,
3-phenylpropanoic acid anhydride,
2-butyric anhydride,
2-pentanoic acid anhydride,
3-butyric anhydride,
3-pentanoic acid anhydride,
4-pentynic acid anhydride, etc.
And their analogues.

As specific examples of the acid anhydride wherein R ¹ and R ² are an aryl group,
Benzoic anhydride,
4-methylbenzoic anhydride,
4-ethylbenzoic anhydride,
4-tert-butylbenzoic anhydride,
2-methylbenzoic anhydride,
2,4,6-trimethylbenzoic anhydride,
1-naphthalene carboxylic acid anhydride,
2-naphthalenecarboxylic acid anhydride, etc.
And their analogues.

Further, examples of R ^1, R ² is an acid anhydride substituted with a halogen atom, primarily cited example has been anhydride substituted with a fluorine atom are set forth below, some or all of these fluorine atoms An acid anhydride obtained by substitution to a chlorine atom, a bromine atom or an iodine atom is also included in the exemplified compounds.

Examples of acid anhydrides in which R ¹ and R ² are linear alkyl groups substituted with a halogen atom include fluoroacetic acid anhydride,
Difluoroacetic anhydride,
Trifluoroacetic anhydride,
2-fluoropropionic anhydride,
2,2-difluoropropionic anhydride,
2,3-Difluoropropionic anhydride,
2,2,3-trifluoropropionic anhydride,
2,3,3-Trifluoropropionic anhydride,
2,2,3,3-tetrapropionic anhydride,
2,3,3,3-tetrapropionic anhydride,
3-fluoropropionic anhydride,
3,3-difluoropropionic acid anhydride,
3,3,3-trifluoropropionic anhydride,
Perfluoropropionic anhydride, etc.
And their analogues.

Examples of acid anhydrides in which R ¹ and R ² are cyclic alkyl groups substituted with a halogen atom include 2-fluorocyclopentanecarboxylic acid anhydride,
3-fluorocyclopentanecarboxylic acid anhydride,
4-fluorocyclopentanecarboxylic acid anhydride and the like,
And their analogues etc.

As an example of the acid anhydride which is an alkenyl group by which R < ¹ >, R < ² > was substituted by the halogen atom,
2-fluoroacrylic anhydride,
3-fluoroacrylic anhydride,
2,3-Difluoroacrylic anhydride,
3, 3-difluoroacrylic anhydride,
2,3,3-trifluoroacrylic anhydride,
2- (trifluoromethyl) acrylic anhydride,
3- (trifluoromethyl) acrylic anhydride,
2,3-bis (trifluoromethyl) acrylic anhydride,
2,3,3-Tris (trifluoromethyl) acrylic anhydride,
2- (4-fluorophenyl) acrylic anhydride,
3- (4-fluorophenyl) acrylic anhydride,
2,3-bis (4-fluorophenyl) acrylic anhydride,
3, 3-bis (4-fluorophenyl) acrylic anhydride,
2-fluoro-3-butenoic acid anhydride,
2,2-difluoro-3-butenoic anhydride,
3-fluoro-2-butenoic acid anhydride,
4-fluoro-3-butenoic anhydride,
3,4-Difluoro-3-butenoic anhydride,
3,3,4-Trifluoro-3-butenoic acid anhydride, etc.
And their analogues.

As an example of the acid anhydride which is an alkynyl group by which R < ¹ >, R < ² > was substituted by the halogen atom,
3-fluoro-2-propanoic acid anhydride,
3- (4-Fluorophenyl) -2-propanoic acid anhydride,
3- (2,3,4,5,6-pentafluorophenyl) -2-propanoic acid anhydride,
4-fluoro-2-butyric anhydride,
4,4-Difluoro-2-butyric anhydride,
4,4,4-Trifluoro-2-butyric anhydride, etc.,
And their analogues.

Examples of acid anhydrides in which R ¹ and R ² are aryl groups substituted with a halogen atom are
4-fluorobenzoic acid anhydride,
2,3,4,5,6-pentafluorobenzoic acid anhydride,
4-trifluoromethylbenzoic anhydride and the like,
And their analogues.

Examples of acid anhydrides having a substituent having a functional group such as ester, nitrile, ketone or ether as R ¹ and R ² are methoxyformic acid anhydride,
Ethoxyformic anhydride,
Methyl oxalic anhydride,
Ethyl oxalic anhydride,
2-cyanoacetic acid anhydride,
2-oxopropionic anhydride,
3-oxobutanoic anhydride,
4-acetylbenzoic acid anhydride,
Methoxy acetic anhydride,
4-methoxybenzoic anhydride and the like,
And their analogues.

Subsequently, specific examples of acid anhydrides in which R ¹ and R ² are different from each other are listed below.
As the examples of R ¹ and R ² mentioned above, and all combinations of their analogues are conceivable, representative examples are given below.

Examples of combinations of linear alkyl groups are
Acetic acid propionic acid anhydride,
Butanoic acid anhydride,
Butanoic acid propionic acid anhydride,
Acetic acid 2-methylpropionic acid anhydride and the like can be mentioned.

Examples of combinations of chain alkyl groups and cyclic alkyl groups are
Acetic acid cyclopentanic acid anhydride,
Acetic acid cyclohexane anhydride,
Cyclopentanoic acid propionic acid anhydride and the like.

As an example of the combination of a linear alkyl group and an alkenyl group,
Acetic acid acrylic anhydride,
Acetic acid 3-methylacrylic anhydride,
Acetic acid 3-butenoic anhydride,
And acrylic acid propionic acid anhydride, and the like.

As an example of the combination of a linear alkyl group and an alkynyl group,
Propylene anhydride,
Acetic acid 2-butyric anhydride,
Acetic acid 3-butyric anhydride,
Acetic acid 3-phenylpropanoic acid anhydride,
Propionic acid propionic acid anhydride and the like can be mentioned.

Examples of combinations of linear alkyl groups and aryl groups are
Acetic acid benzoic acid anhydride,
Acetic acid 4-methylbenzoic anhydride,
Acetic acid 1-naphthalenecarboxylic acid anhydride,
Benzoic acid propionic acid anhydride and the like can be mentioned.

Examples of combinations of linear alkyl groups and hydrocarbon groups having a functional group are
Acetic acid fluoroacetic anhydride,
Trifluoroacetic anhydride,
Acetic acid 4-fluorobenzoic acid anhydride,
Fluoroacetic propionic acid anhydride,
Alkyl acetate oxalic acid anhydride,
Acetic acid 2-cyanoacetic anhydride,
Acetic acid 2-oxopropionic acid anhydride,
Acetic acid methoxyacetic anhydride,
Methoxy acetic acid propionic acid anhydride etc. are mentioned.

Examples of combinations of cyclic alkyl groups are
Cyclopentanic acid cyclohexane anhydride, etc. may be mentioned.
Examples of combinations of cyclic alkyl groups and alkenyl groups are
Acrylic acid cyclopentanic acid anhydride,
3-methylacrylic acid cyclopentanic acid anhydride,
3-butenoic acid cyclopentanic acid anhydride,
And acrylic acid and cyclohexane anhydride.

Examples of combinations of cyclic alkyl groups and alkynyl groups are
Propynic acid cyclopentanic acid anhydride,
2-butyric acid cyclopentanic acid anhydride,
Propynoic acid cyclohexane acid anhydride and the like can be mentioned.
Examples of combinations of cyclic alkyl groups and aryl groups are
Benzoic acid cyclopentanic acid anhydride,
4-methylbenzoic acid cyclopentanic acid anhydride,
Benzoic acid cyclohexane acid anhydride and the like can be mentioned.

Examples of combinations of cyclic alkyl groups and hydrocarbon groups having functional groups are
Fluoroacetic acid cyclopentanic anhydride,
Cyclopentanoic acid trifluoroacetic anhydride,
Cyclopentanoic acid 2-cyanoacetic acid anhydride,
Cyclopentanoic acid methoxyacetic acid anhydride,
Examples thereof include cyclohexane acid fluoroacetic acid anhydride and the like.

Examples of combinations of alkenyl groups are
Acrylic acid 2-methylacrylic anhydride,
Acrylic acid 3-methylacrylic anhydride,
Acrylic acid 3-butene anhydride,
2-methyl acrylic acid 3-methyl acrylic anhydride, etc. are mentioned.

As an example of the combination of an alkenyl group and an alkynyl group,
Propanoic acid acrylic acid anhydride,
Acrylic acid 2-butyric anhydride,
2-Methyl acrylic acid propanoic acid anhydride and the like.

As an example of the combination of an alkenyl group and an aryl group,
Acrylic acid benzoic anhydride,
Acrylic acid 4-methylbenzoic anhydride,
2-methylacrylic acid benzoic acid anhydride, and the like.

As an example of the combination of the alkenyl group and the hydrocarbon group which has a functional group,
Acrylic acid fluoroacetic anhydride,
Acrylic acid trifluoroacetic acid anhydride,
Acrylic acid 2-cyanoacetic acid anhydride,
Acrylic acid methoxyacetic anhydride,
And 2-methylacrylic acid fluoroacetic acid anhydride.

Examples of combinations of alkynyl groups are:
Propynic acid 2-butyric anhydride,
Propynic acid 3-butyric anhydride,
2-butyric acid 3-butyric acid anhydride and the like.

As an example of the combination of an alkynyl group and an aryl group,
Propanoic acid benzoic acid anhydride,
4-Methylbenzoic acid propanoic acid anhydride,
Benzoic acid 2-butyric acid anhydride and the like can be mentioned.

Examples of combinations of an alkynyl group and a hydrocarbon group having a functional group are
Propynoic acid fluoroacetic anhydride,
Propynic acid trifluoroacetic acid anhydride,
Propynoic acid 2-cyanoacetic anhydride,
Propynoic acid methoxyacetic anhydride,
2-butyric acid fluoroacetic acid anhydride and the like.

Examples of combinations of aryl groups are:
Benzoic acid 4-methylbenzoic acid anhydride,
Benzoic acid 1-naphthalenecarboxylic acid anhydride,
4-methylbenzoic acid 1-naphthalenecarboxylic acid anhydride and the like.

Examples of combinations of aryl groups and hydrocarbon groups having functional groups are
Benzoic acid fluoroacetic anhydride,
Benzoic acid trifluoroacetic acid anhydride,
Benzoic acid 2-cyanoacetic anhydride,
Benzoic acid methoxyacetic anhydride,
And 4-methylbenzoic acid fluoroacetic acid anhydride.

As an example of a combination of hydrocarbon groups having a functional group,
Fluoroacetic acid trifluoroacetic acid anhydride,
Fluoroacetic acid 2-cyanoacetic acid anhydride,
Fluoroacetic acid methoxyacetic anhydride,
Trifluoroacetic acid 2-cyanoacetic acid anhydride and the like can be mentioned.

Of the above acid anhydrides forming a chain structure, preferably acetic anhydride,
Propionic anhydride,
2-Methylpropionic anhydride,
Cyclopentanecarboxylic acid anhydride,
Cyclohexane carboxylic acid anhydride etc.
Acrylic anhydride,
2-methyl acrylic anhydride,
3-methylacrylic anhydride,
2,3-Dimethylacrylic anhydride,
3, 3-dimethyl acrylic anhydride,
3-butenoic anhydride,
2-Methyl-3-butenoic anhydride,
Propynic anhydride,
2-butyric anhydride,
Benzoic anhydride,
2-methylbenzoic anhydride,
4-methylbenzoic anhydride,
4-tert-butylbenzoic anhydride,
Trifluoroacetic anhydride,
3,3,3-trifluoropropionic anhydride,
2- (trifluoromethyl) acrylic anhydride,
2- (4-fluorophenyl) acrylic anhydride,
4-fluorobenzoic acid anhydride,
2,3,4,5,6-pentafluorobenzoic acid anhydride,
Methoxyformic anhydride,
Ethoxyformic anhydride,
And more preferably
Acrylic anhydride,
2-methyl acrylic anhydride,
3-methylacrylic anhydride,
Benzoic anhydride,
2-methylbenzoic anhydride,
4-methylbenzoic anhydride,
4-tert-butylbenzoic anhydride,
4-fluorobenzoic acid anhydride,
2,3,4,5,6-pentafluorobenzoic acid anhydride,
Methoxyformic anhydride,
Ethoxyformic anhydride,
It is.

These compounds can improve the charge / discharge rate characteristics, the input / output characteristics, and the impedance characteristics after the durability test, in particular, by forming a bond with a lithium oxalate salt appropriately to form a film excellent in durability. It is preferable from the viewpoint of
Subsequently, specific examples of the acid anhydride in which R ¹ and R ² are bonded to each other to form a cyclic structure are listed below.

First, as specific examples of the acid anhydride in which R ¹ and R ² are bonded to each other to form a 5-membered ring structure,
Succinic anhydride,
4-methylsuccinic anhydride,
4,4-dimethylsuccinic anhydride,
4,5-dimethylsuccinic anhydride,
4,4,5-trimethylsuccinic anhydride,
4,4,5,5-Tetramethylsuccinic anhydride,
4-vinylsuccinic anhydride,
4,5-divinylsuccinic anhydride,
4-phenylsuccinic anhydride,
4,5-Diphenylsuccinic anhydride,
4,4-diphenylsuccinic anhydride,
Citraconic anhydride,
maleic anhydride,
4-methylmaleic anhydride,
4,5-dimethylmaleic anhydride,
4-phenylmaleic anhydride,
4,5-Diphenylmaleic anhydride,
Itaconic anhydride,
5-methylitaconic anhydride,
5,5-Dimethylitaconic anhydride,
Phthalic anhydride,
3,4,5,6-tetrahydrophthalic anhydride etc.,
And their analogues.

Specific examples of the acid anhydride in which R ¹ and R ² are bonded to each other to form a 6-membered ring structure include cyclohexane-1,2-dicarboxylic acid anhydride,
4-cyclohexene-1,2-dicarboxylic acid anhydride,
Glutaric anhydride etc.,
And their analogues.

Specific examples of the acid anhydride in which R ¹ and R ² are bonded to each other to form another cyclic structure are as follows:
5-norbornene-2,3-dicarboxylic acid anhydride,
Cyclopentane tetracarboxylic acid dianhydride,
Pyromellitic anhydride,
Diglycolic acid anhydride, etc.
And their analogues.

As specific examples of the acid anhydride substituted with a halogen atom while R ¹ and R ² are mutually bonded to form a cyclic structure,
4-fluorosuccinic anhydride,
4,4-difluorosuccinic anhydride,
4,5-Difluorosuccinic anhydride,
4,4,5-Trifluorosuccinic anhydride,
4,4,5,5-tetrafluorosuccinic anhydride,
4-fluoromaleic anhydride,
4,5-difluoromaleic anhydride,
5-fluoroitaconic anhydride,
5,5-Difluoroitaconic anhydride etc.,
And their analogues.

Among the above-mentioned acid anhydrides in which R ¹ and R ² are bonded, preferably
Succinic anhydride,
4-methylsuccinic anhydride,
4-vinylsuccinic anhydride,
4-phenylsuccinic anhydride,
Citraconic anhydride,
maleic anhydride,
4-methylmaleic anhydride,
4-phenylmaleic anhydride,
Itaconic anhydride,
5-methylitaconic anhydride,
Glutaric anhydride,
Phthalic anhydride,
Cyclohexane-1,2-dicarboxylic anhydride,
5-norbornene-2,3-dicarboxylic acid anhydride,
Cyclopentane tetracarboxylic acid dianhydride,
Pyromellitic anhydride,
4-fluorosuccinic anhydride,
4-fluoromaleic anhydride,
5-fluoroitaconic anhydride,
And more preferably
Succinic anhydride,
4-methylsuccinic anhydride,
4-vinylsuccinic anhydride,
Citraconic anhydride,
Cyclohexane-1,2-dicarboxylic anhydride,
5-norbornene-2,3-dicarboxylic acid anhydride,
Cyclopentane tetracarboxylic acid dianhydride,
Pyromellitic anhydride,
4-fluorosuccinic anhydride,
It is. These compounds are preferable because they form a bond with a lithium oxalate salt appropriately to form a film excellent in durability, and in particular, in order to improve the capacity retention ratio after a durability test.

The molecular weight of the specific compound is not limited and is arbitrary unless the effects of the present invention are significantly impaired, but is usually 90 or more, preferably 95 or more, and is usually 300 or less, preferably 200 or less. When the molecular weight of the specific compound is in the above range, the increase in viscosity of the electrolytic solution can be suppressed, and the film density can be optimized, so that the durability can be appropriately improved.
Moreover, there is no restriction | limiting in particular also in the manufacturing method of a specific compound, It is possible to select and manufacture a well-known method arbitrarily. The specific compounds described above may be contained alone in the non-aqueous electrolyte solution of the present invention, or two or more may be used together in any combination and ratio.

Further, the content of the specific compound to the non-aqueous electrolytic solution of the present invention is not particularly limited, and is optional unless the effect of the present invention is significantly impaired. % By mass or more, preferably 0.010% by mass or more, more preferably 0.050% by mass or more, still more preferably 0.10% by mass or more, and usually less than 1.0% by mass, preferably 0.9% by mass It is desirable to contain it by the density | concentration of 0.8 mass% or less more preferably more preferably.
When the content of the specific compound is in the above range, the effect of improving cycle characteristics is easily exhibited, and since the reactivity is suitable, the battery characteristics are easily improved.

<1-1-6. Lithium oxalate salt and compound represented by the general formula (1)>
In the present invention, the mass% [B] of the lithium oxalate salt with respect to the whole non-aqueous electrolyte and the mass% [C] of the compound represented by the general formula (1) satisfy [B] ≧ [C] and [B] It is + [C] <2.0 mass%.

  When [B] C [C], the compound represented by the general formula (1) appropriately forms a bond with the lithium oxalate salt at the time of initial charge, and the compound represented by the general formula (1) is lithium By reducing the reactivity with solvent species other than the oxalate salt, a film having high durability and low resistance can be formed.

  [B] + [C] is preferably 1.8% by mass or less, more preferably 1.6% by mass or less, still more preferably 1.0% by mass or less, in order to exert the effects of the present invention more significantly. It is. The lower limit is not particularly limited, but generally 0.0010% by mass or more, preferably 0.010% by mass or more, more preferably 0.10% by mass or more, further preferably 0.20% by mass or more Preferably it is 0.30 mass% or more. When [B] + [C] is in the above range, the amount of film formed on the electrode surface becomes an appropriate range, high temperature storage characteristics and cycle characteristics are high, and high output characteristics and charge / discharge rate characteristics can be realized. .

<1-2. Non-aqueous solvent>
<1-2-1. Saturated cyclic carbonate>
As a saturated cyclic carbonate, what has a C2-C4 alkylene group is mentioned.
Specifically, ethylene carbonate, a propylene carbonate, a butylene carbonate etc. are mentioned as a C2-C4 saturated cyclic carbonate. Among them, ethylene carbonate and propylene carbonate are particularly preferable from the viewpoint of the improvement of the battery characteristics derived from the improvement of the lithium ion dissociation degree.
The saturated cyclic carbonates may be used alone or in any combination of two or more in any proportion.

  The content of the saturated cyclic carbonate is not particularly limited and is optional as long as the effects of the present invention are not significantly impaired. However, the content in the case of using one kind alone is 3% by volume in 100% by volume of the non-aqueous solvent The above content is more preferably 5% by volume or more. By setting it in this range, a decrease in the electrical conductivity resulting from a decrease in the dielectric constant of the non-aqueous electrolyte solution is avoided, and the large current discharge characteristics of the non-aqueous electrolyte secondary battery, the stability to the negative electrode, and the cycle characteristics are excellent. Range is easy. Also, it is usually 90% by volume or less, preferably 85% by volume or less, more preferably 80% by volume or less. By setting the viscosity in this range, the viscosity of the non-aqueous electrolyte solution can be set to an appropriate range, the decrease in ion conductivity can be suppressed, and the load characteristics of the non-aqueous electrolyte secondary battery can be easily set in a good range.

Moreover, saturated cyclic carbonate can also be used in arbitrary combination of 2 or more types. One preferred combination is a combination of ethylene carbonate and propylene carbonate. In this case, the volume ratio of ethylene carbonate to propylene carbonate is preferably 99: 1 to 40:60, and particularly preferably 95: 5 to 50:50. Furthermore, the amount of propylene carbonate in the whole non-aqueous solvent is not particularly limited and is optional unless the effects of the present invention are significantly impaired, but usually 1% by volume or more, preferably 2% by volume or more, more preferably 3 It is at least 30% by volume, preferably at most 25% by volume, more preferably at most 20% by volume. It is preferable to contain propylene carbonate in this range because the low temperature characteristics are further excellent while maintaining the characteristics of the combination of ethylene carbonate and dialkyl carbonates.

<1-2-2. Linear carbonate>
As a linear carbonate, a C3-C7 thing is preferable.
Specifically, as linear carbonates having 3 to 7 carbon atoms, dimethyl carbonate, diethyl carbonate, di-n-propyl carbonate, diisopropyl carbonate, n-propyl isopropyl carbonate, ethyl methyl carbonate, methyl-n-propyl carbonate, n-Butyl methyl carbonate, isobutyl methyl carbonate, t-butyl methyl carbonate, ethyl-n-propyl carbonate, n-butyl ethyl carbonate, isobutyl ethyl carbonate, t-butyl ethyl carbonate and the like can be mentioned.

  Among them, dimethyl carbonate, diethyl carbonate, di-n-propyl carbonate, diisopropyl carbonate, n-propyl isopropyl carbonate, ethyl methyl carbonate and methyl-n-propyl carbonate are preferable, and dimethyl carbonate, diethyl carbonate and ethyl methyl carbonate are particularly preferable. is there.

  In addition, linear carbonates having a fluorine atom (hereinafter sometimes abbreviated as "fluorinated linear carbonate") can also be suitably used. The number of fluorine atoms contained in the fluorinated linear carbonate is not particularly limited as long as it is 1 or more, but is usually 6 or less, preferably 4 or less. When the fluorinated linear carbonate has a plurality of fluorine atoms, they may be bonded to the same carbon as each other or to different carbons. Examples of fluorinated linear carbonates include fluorinated dimethyl carbonate derivatives, fluorinated ethyl methyl carbonate derivatives, fluorinated diethyl carbonate derivatives and the like.

  Examples of fluorinated dimethyl carbonate derivatives include fluoromethyl methyl carbonate, difluoromethyl methyl carbonate, trifluoromethyl methyl carbonate, bis (fluoromethyl) carbonate, bis (difluoro) methyl carbonate, bis (trifluoromethyl) carbonate and the like.

  Examples of fluorinated ethyl methyl carbonate derivatives include 2-fluoroethyl methyl carbonate, ethyl fluoromethyl carbonate, 2,2-difluoroethyl methyl carbonate, 2-fluoroethyl fluoromethyl carbonate, ethyl difluoromethyl carbonate, 2,2,2-triethyl carbonate Fluoroethyl methyl carbonate, 2, 2- difluoro ethyl fluoro methyl carbonate, 2- fluoro ethyl difluoro methyl carbonate, ethyl trifluoromethyl carbonate etc. are mentioned.

  As fluorinated diethyl carbonate derivatives, ethyl- (2-fluoroethyl) carbonate, ethyl- (2,2-difluoroethyl) carbonate, bis (2-fluoroethyl) carbonate, ethyl- (2,2,2-trifluoro Ethyl) carbonate, 2,2-difluoroethyl-2'-fluoroethyl carbonate, bis (2,2-difluoroethyl) carbonate, 2,2,2-trifluoroethyl-2'-fluoroethyl carbonate, 2,2, 2-trifluoroethyl-2 ', 2'-difluoroethyl carbonate, bis (2,2,2-trifluoroethyl) carbonate, etc. are mentioned.

As the chain carbonate, one type may be used alone, or two or more types may be used in combination in an optional combination and ratio.
The content of the linear carbonate is not particularly limited, but is usually 15% by volume or more, preferably 20% by volume or more, and more preferably 25% by volume or more in 100% by volume of the non-aqueous solvent. Also, it is usually 90% by volume or less, preferably 85% by volume or less, more preferably 80% by volume or less. By setting the content of the linear carbonate in the above range, the viscosity of the non-aqueous electrolytic solution is made to be an appropriate range, and the decrease in ion conductivity is suppressed, and thus the input / output characteristics and charge / discharge of the non-aqueous electrolytic solution secondary battery It becomes easy to make the rate characteristic into a good range. In addition, it is possible to avoid the decrease in the electrical conductivity due to the decrease in the dielectric constant of the non-aqueous electrolyte solution, and to easily set the input / output characteristics and charge / discharge rate characteristics of the non-aqueous electrolyte solution secondary battery.
Furthermore, battery performance can be remarkably improved by combining ethylene carbonate in a specific content with a specific linear carbonate.

  For example, when dimethyl carbonate and ethyl methyl carbonate are selected as the specific chain carbonate, the content of ethylene carbonate is not particularly limited and is optional unless the effects of the present invention are significantly impaired, but usually 15% by volume or more The preferred content of dimethyl carbonate is usually 20% by volume or more, preferably 30% by volume or more, and usually 50% by volume or less. It is preferably 45% by volume or less, and the content of ethyl methyl carbonate is usually 20% by volume or more, preferably 30% by volume or more, and usually 50% by volume or less, preferably 45% by volume or less. By setting the content within the above range, it is possible to lower the viscosity of the non-aqueous electrolytic solution while lowering the low temperature deposition temperature of the electrolyte, improve the ion conductivity, and obtain high input / output even at low temperature.

1-2-3. Cyclic carbonate having fluorine atom>
The cyclic carbonate having a fluorine atom (hereinafter sometimes abbreviated as "fluorinated cyclic carbonate") is not particularly limited as long as it is a cyclic carbonate having a fluorine atom.
Examples of fluorinated cyclic carbonates include derivatives of cyclic carbonates having an alkylene group of 2 to 6 carbon atoms, such as ethylene carbonate derivatives. Examples of ethylene carbonate derivatives include ethylene carbonate or fluorinated compounds of ethylene carbonate substituted with an alkyl group (for example, an alkyl group having 1 to 4 carbon atoms), among which one having 1 to 8 fluorine atoms Is preferred.

  Specifically, monofluoroethylene carbonate, 4,4-difluoroethylene carbonate, 4,5-difluoroethylene carbonate, 4-fluoro-4-methylethylene carbonate, 4,5-difluoro-4-methylethylene carbonate, 4- Fluoro-5-methylethylene carbonate, 4,4-difluoro-5-methylethylene carbonate, 4- (fluoromethyl) -ethylene carbonate, 4- (difluoromethyl) -ethylene carbonate, 4- (trifluoromethyl) -ethylene carbonate 4- (fluoromethyl) -4-fluoroethylene carbonate, 4- (fluoromethyl) -5-fluoroethylene carbonate, 4-fluoro-4,5-dimethylethylene carbonate, 4,5-difluoro-4,5-dimeth Le ethylene carbonate, 4,4-difluoro-5,5-dimethylethylene carbonate.

  Among them, at least one selected from the group consisting of monofluoroethylene carbonate, 4,4-difluoroethylene carbonate, 4,5-difluoroethylene carbonate, and 4,5-difluoro-4,5-dimethylethylene carbonate has high ion conductivity. It is more preferable in terms of imparting properties and suitably forming an interfacial protective film.

The fluorinated cyclic carbonates may be used alone or in any combination of two or more in any proportion. The content of the fluorinated cyclic carbonate is not particularly limited, and is optional as long as the effects of the present invention are not significantly impaired. However, the content is usually 0.001% by mass or more in 100% by mass of the non-aqueous electrolytic solution. .01% by mass or more, more preferably 0.1% by mass or more, and usually 85% by mass or less, preferably 80% by mass or less, more preferably 75% by mass or less.
The fluorinated cyclic carbonate may be used as a main solvent for the non-aqueous electrolyte solution or as a sub-solvent. The content of the fluorinated cyclic carbonate when used as the main solvent is usually 8% by mass or more, preferably 10% by mass or more, and more preferably 12% by mass or more, in 100% by mass of the non-aqueous electrolyte solution. Also, it is usually 85% by mass or less, preferably 80% by mass or less, and more preferably 75% by mass or less. Within this range, it is easy for the non-aqueous electrolyte secondary battery to exhibit a sufficient cycle characteristic improvement effect, and a decrease in the discharge capacity retention rate is easily avoided. In addition, the content of the fluorinated cyclic carbonate in the case of using as a secondary solvent is usually 0.001% by mass or more, preferably 0.01% by mass or more, and more preferably 100% by mass of the non-aqueous electrolyte solution. Is 0.1% by mass or more, and usually 8% by mass or less, preferably 6% by mass or less, and more preferably 5% by mass or less. Within this range, the non-aqueous electrolyte secondary battery is likely to exhibit sufficient input / output characteristics and charge / discharge rate characteristics.

1-2-4. Linear carboxylic acid ester>
The chain carboxylic acid ester includes one having 3 to 7 carbon atoms in its structural formula.
Specifically, methyl acetate, ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, t-butyl acetate, methyl propionate, ethyl propionate, n-propyl propionate, Isopropyl propionate, n-butyl propionate, isobutyl propionate, t-butyl propionate, methyl butyrate, ethyl butyrate, n-propyl butyrate, isopropyl butyrate, methyl isobutyrate, ethyl isobutyrate, isobutyrate-n- Propyl, isopropyl isobutyrate and the like can be mentioned.

  Among them, methyl acetate, ethyl acetate, n-propyl acetate, n-butyl acetate, methyl propionate, ethyl propionate, n-propyl propionate, isopropyl propionate, methyl butyrate, ethyl butyrate, etc. are due to viscosity reduction. It is preferable from the point of the improvement of ion conductivity.

  The content of the linear carboxylic acid ester is not particularly limited, and is optional as long as the effects of the present invention are not significantly impaired, but usually 5% by volume or more, preferably 8% by volume or more in 100% by volume of the non-aqueous solvent. And generally 80% by volume or less, preferably 70% by volume or less. When the content of the linear carboxylic acid ester is in the above range, the electrical conductivity of the non-aqueous electrolytic solution is improved, and the input / output characteristics and charge / discharge rate characteristics of the non-aqueous electrolytic solution secondary battery are easily improved. In addition, the increase in negative electrode resistance can be suppressed, and the input / output characteristics and charge / discharge rate characteristics of the non-aqueous electrolyte solution secondary battery can be easily set in a favorable range.

<1-2-5. Cyclic carboxylic acid ester>
The cyclic carboxylic acid ester includes one having 3 to 12 carbon atoms in its structural formula.
Specifically, gamma butyrolactone, gamma valerolactone, gamma caprolactone, epsilon caprolactone and the like can be mentioned. Among them, gamma-butyrolactone is particularly preferable from the viewpoint of the improvement of the battery characteristics derived from the improvement of the lithium ion dissociation degree.

The content of the cyclic carboxylic acid ester is not particularly limited, and is optional as long as the effects of the present invention are not significantly impaired, but usually 3% by volume or more, preferably 5% by volume in 100% by volume of the non-aqueous solvent
It is the above, and usually 60 volume% or less, preferably 50 volume% or less. When the content of the cyclic carboxylic acid ester is in the above range, the electrical conductivity of the non-aqueous electrolytic solution is improved, and the input / output characteristics and charge / discharge rate characteristics of the non-aqueous electrolytic solution secondary battery are easily improved. In addition, the viscosity of the non-aqueous electrolyte solution is set in an appropriate range to avoid a decrease in electrical conductivity, and the increase in negative electrode resistance is suppressed, and the input / output characteristics and charge / discharge rate characteristics of the non-aqueous electrolyte secondary battery are good ranges It becomes easy to do.

<1-2-6. Ether compounds>
As an ether type compound, a C3-C10 linear ether and C3-C6 cyclic ether are preferable.
As a C3-C10 linear ether, diethyl ether, di (2-fluoroethyl) ether, di (2,2-difluoroethyl) ether, di (2,2,2-trifluoroethyl) ether, ethyl (2-fluoroethyl) ether, ethyl (2,2,2-trifluoroethyl) ether, ethyl (1,1,2,2-tetrafluoroethyl) ether, (2-fluoroethyl) (2,2,2 -Trifluoroethyl) ether, (2-fluoroethyl) (1,1,2,2-tetrafluoroethyl) ether, (2,2,2-trifluoroethyl) (1,1,2,2-tetrafluoro) Ethyl) ether, ethyl-n-propylether, ethyl (3-fluoro-n-propyl) ether, ethyl (3,3,3-trifluoro-n-propyl) -Ether, ethyl (2,2,3,3-tetrafluoro-n-propyl) ether, ethyl (2,2,3,3,3-pentafluoro-n-propyl) ether, 2-fluoroethyl-n-propyl Ether, (2-fluoroethyl) (3-fluoro-n-propyl) ether, (2-fluoroethyl) (3,3,3-trifluoro-n-propyl) ether, (2-fluoroethyl) (2,2, 2,3,3-Tetrafluoro-n-propyl) ether, (2-fluoroethyl) (2,2,3,3,3-pentafluoro-n-propyl) ether, 2,2,2-trifluoroethyl -N-propyl ether, (2,2,2-trifluoroethyl) (3-fluoro-n-propyl) ether, (2,2,2-trifluoroethyl) (3,3,3-trif Or-n-propyl) ether, (2,2,2-trifluoroethyl) (2,2,3,3-tetrafluoro-n-propyl) ether, (2,2,2-trifluoroethyl) (2 2,2,3,3-Pentafluoro-n-propyl) ether, 1,1,2,2-tetrafluoroethyl-n-propylether, (1,1,2,2-tetrafluoroethyl) (3) -Fluoro-n-propyl) ether, (1,1,2,2-tetrafluoroethyl) (3,3,3-trifluoro-n-propyl) ether, (1,1,2,2-tetrafluoroethyl) ) (2,2,3,3-tetrafluoro-n-propyl) ether, (1,1,2,2-tetrafluoroethyl) (2,2,3,3,3-pentafluoro-n-propyl) Ether, di-n-propyl Ether, (n-propyl) (3-fluoro-n-propyl) ether, (n-propyl) (3,3,3-trifluoro-n-propyl) ether, (n-propyl) (2,2,3 , 3-Tetrafluoro-n-propyl) ether, (n-propyl) (2,2,3,3,3-pentafluoro-n-propyl) ether, di (3-fluoro-n-propyl) ether, 3-fluoro-n-propyl) (3,3,3-trifluoro-n-propyl) ether, (3-fluoro-n-propyl) (2,2,3,3-tetrafluoro-n-propyl) ether , (3-fluoro-n-propyl) (2,2,3,3,3-pentafluoro-n-propyl) ether, di (3,3,3-trifluoro-n-propyl) ether, (3, 3, 3- Triful Ro-n-propyl) (2,2,3,3-tetrafluoro-n-propyl) ether, (3,3,3-trifluoro-n-propyl) (2,2,3,3,3-penta) Fluoro-n-propyl) ether, di (2,2,3,3-tetrafluoro-n-propyl) ether, (2,2,3,3-tetrafluoro-n-propyl) (2,2,3,3 3,3-Pentafluoro-n-propyl) ether, di (2,2,3,3,3-pentafluoro-n-propyl) ether, di-n-butylether, dimethoxymethane, methoxyethoxymethane, methoxy (2 -Fluoroethoxy) methane, methoxy (2,2,2-trifluoroethoxy) methanemethoxy (1,1,2,2-tetrafluoroethoxy) methane, diethoxymethane, ethoxy (2-flu Roethoxy) methane, ethoxy (2,2,2-trifluoroethoxy) methane, ethoxy (1,1,2,2-tetrafluoroethoxy) methane, di (2-fluoroethoxy) methane, (2-fluoroethoxy) ( 2,2,2-trifluoroethoxy) methane, (2-fluoroethoxy) (1,1,2,2-tetrafluoroethoxy) methanedi (2,2,2-trifluoroethoxy) methane, (2,2,2-trifluoroethoxy) methane 2-trifluoroethoxy) (1,1,2,2-tetrafluoroethoxy) methane, di (1,1,2,2-tetrafluoroethoxy) methane, dimethoxyethane, methoxyethoxyethane, methoxy (2-fluoroethoxy) ) Ethane, methoxy (2,2,2-trifluoroethoxy) ethane, methoxy (1,1,2,2-tetrafluoroethene X) ethane, diethoxyethane, ethoxy (2-fluoroethoxy) ethane, ethoxy (2,2,2-trifluoroethoxy) ethane, ethoxy (1,1,2,2-tetrafluoroethoxy) ethane, di (2 -Fluoroethoxy) ethane, (2-fluoroethoxy) (2,2,2-trifluoroethoxy) ethane, (2-fluoroethoxy) (1,1,2,2-tetrafluoroethoxy) ethane, di (2,2,2-fluoroethoxy) ethane 2,2-trifluoroethoxy) ethane, (2,2,2-trifluoroethoxy) (1,1,2,2-tetrafluoroethoxy) ethane, di (1,1,2,2-tetrafluoroethoxy) Ethane, ethylene glycol di-n-propyl ether, ethylene glycol di-n-butyl ether, diethylene glycol dimethyl ether, etc. And the like.

The cyclic ether having 3 to 6 carbon atoms includes tetrahydrofuran, 2-methyltetrahydrofuran, 3-methyltetrahydrofuran, 1,3-dioxane, 2-methyl-1,3-dioxane, 4-methyl-1,3-dioxane, 1 And 4-dioxane etc., and fluorinated compounds thereof.
Among them, dimethoxymethane, diethoxymethane, ethoxymethoxymethane, ethylene glycol di-n-propyl ether, ethylene glycol di-n-butyl ether, and diethylene glycol dimethyl ether have high solvation ability to lithium ions and improve ion dissociation. From the viewpoint of low viscosity and high ionic conductivity, dimethoxymethane, diethoxymethane and ethoxymethoxymethane are particularly preferable.

  The content of the ether-based compound is not particularly limited and is optional unless the effects of the present invention are significantly impaired, but generally 1% by volume or more, preferably 2% by volume or more, in 100% by volume of the non-aqueous solvent Is 3% by volume or more, and usually 30% by volume or less, preferably 25% by volume or less, and more preferably 20% by volume or less. If the content of the ether-based compound is within the above range, it is easy to ensure the improvement of the lithium ion dissociation degree of the chain ether and the improvement of the ion conductivity derived from the viscosity decrease. In addition, when the negative electrode active material is a carbonaceous material, the phenomenon of chain ether co-insertion with lithium ions can be suppressed, so that input / output characteristics and charge / discharge rate characteristics can be set in appropriate ranges.

<1-2-7. Sulfone compound>
As a sulfone type compound, a C3-C6 cyclic sulfone and a C2-C6 chain-like sulfone are preferable. The number of sulfonyl groups in one molecule is preferably 1 or 2.
Examples of cyclic sulfones include monosulfone compounds such as trimethylenesulfones, tetramethylenesulfones, hexamethylenesulfones, disulfone compounds such as trimethylenedisulfones, tetramethylenedisulfones, and hexamethylenedisulfones. Among them, tetramethylene sulfones, tetramethylene disulfones, hexamethylene sulfones and hexamethylene disulfones are more preferable, and tetramethylene sulfones (sulfolanes) are particularly preferable, from the viewpoint of dielectric constant and viscosity.

As the sulfolanes, sulfolanes and / or sulfolane derivatives (hereinafter sometimes abbreviated as “sulfolanes including sulfolanes”) are preferable. As the sulfolane derivative, one in which at least one hydrogen atom bonded to a carbon atom constituting a sulfolane ring is substituted with a fluorine atom or an alkyl group is preferable.

  Among them, 2-methylsulfolane, 3-methylsulfolane, 2-fluorosulfolane, 3-fluorosulfolane, 2,2-difluorosulfolane, 2,3-difluorosulfolane, 2,4-difluorosulfolane, 2,5-difluorosulfolane, 3,4-Difluorosulfolane, 2-fluoro-3-methylsulfolane, 2-fluoro-2-methylsulfolane, 3-fluoro-3-methylsulfolane, 3-fluoro-2-methylsulfolane, 4-fluoro-3-methylsulfolane Sulfolane, 4-fluoro-2-methylsulfolane, 5-fluoro-3-methylsulfolane, 5-fluoro-2-methylsulfolane, 2-fluoromethylsulfolane, 3-fluoromethylsulfolane, 2-difluoromethylsulfolane, 3-difluoro Methyl sulfolane, 2- Trifluoromethyl sulfolane, 3-trifluoromethyl sulfolane, 2-fluoro-3- (trifluoromethyl) sulfolane, 3-fluoro-3- (trifluoromethyl) sulfolane, 4-fluoro-3- (trifluoromethyl) sulfolane 5-fluoro-3- (trifluoromethyl) sulfolane and the like are preferable in that they have high ion conductivity and high input and output.

  Moreover, as a chain sulfone, dimethyl sulfone, ethyl methyl sulfone, diethyl sulfone, n-propyl methyl sulfone, n-propyl ethyl sulfone, di-n-propyl sulfone, isopropyl methyl sulfone, isopropyl ethyl sulfone, diisopropyl sulfone, n- Butyl methyl sulfone, n-butyl ethyl sulfone, t-butyl methyl sulfone, t-butyl ethyl sulfone, monofluoromethyl methyl sulfone, difluoromethyl methyl sulfone, trifluoromethyl methyl sulfone, monofluoroethyl methyl sulfone, difluoroethyl methyl sulfone, Trifluoroethyl methyl sulfone, pentafluoroethyl methyl sulfone, ethyl monofluoromethyl sulfone, ethyl difluoromethyl sulfone, ethyl trif Omethyl sulfone, perfluoroethyl methyl sulfone, ethyl trifluoroethyl sulfone, ethyl pentafluoroethyl sulfone, di (trifluoroethyl) sulfone, perfluorodiethyl sulfone, fluoromethyl-n-propyl sulfone, difluoromethyl-n-propyl sulfone Trifluoromethyl-n-propyl sulfone, fluoromethyl isopropyl sulfone, difluoromethyl isopropyl sulfone, trifluoromethyl isopropyl sulfone, trifluoroethyl n-propyl sulfone, trifluoroethyl isopropyl sulfone, pentafluoroethyl n-propyl sulfone, Pentafluoroethyl isopropyl sulfone, trifluoroethyl-n-butyl sulfone, trifluoroethyl-t-butyl sulfone Emissions, pentafluoroethyl -n- butyl sulfone, pentafluoroethyl -t- butyl sulfone, and the like.

  Among them, dimethyl sulfone, ethyl methyl sulfone, diethyl sulfone, n-propyl methyl sulfone, isopropyl methyl sulfone, n-butyl methyl sulfone, t-butyl methyl sulfone, monofluoromethyl methyl sulfone, difluoromethyl methyl sulfone, trifluoromethyl methyl sulfone Monofluoroethyl methyl sulfone difluoroethyl methyl sulfone trifluoroethyl methyl sulfone pentafluoroethyl methyl sulfone ethyl monofluoromethyl sulfone ethyl difluoromethyl sulfone ethyl trifluoromethyl sulfone ethyl trifluoroethyl sulfone ethyl pentafluoro Ethyl sulfone, trifluoromethyl-n-propyl sulfone, trifluoromethyl isopropyl sulfone, tri Ruoroechiru -n- butyl sulfone, trifluoroethyl -t- butyl sulfone, trifluoromethyl -n- butyl sulfone, trifluoromethyl -t- butyl sulfone is preferred because a higher high output ionic conductivity.

The content of the sulfone-based compound is not particularly limited and is optional as long as the effects of the present invention are not significantly impaired. However, it is usually 0.3% by volume or more, preferably 0.5% by volume in 100% by volume of non-aqueous solvent The amount is more preferably 1% by volume or more, and usually 40% by volume or less, preferably 35% by volume or less, and more preferably 30% by volume or less. If the content of the sulfone-based compound is within the above range, the effect of improving the durability such as cycle characteristics and storage characteristics can be easily obtained, and the viscosity of the non-aqueous electrolyte solution can be made into an appropriate range to lower the electrical conductivity. Can be avoided, and the input / output characteristics and charge / discharge rate characteristics of the non-aqueous electrolytic solution secondary battery can be made in an appropriate range.

<1-3. Auxiliary agent>
<1-3-1. Cyclic carbonate having carbon-carbon unsaturated bond>
In the non-aqueous electrolytic solution of the present invention, a cyclic carbonate having a carbon-carbon unsaturated bond (hereinafter referred to as “unsaturated” is used to form a film on the negative electrode surface of the non-aqueous electrolytic solution battery and achieve long life of the battery. And may be abbreviated as "cyclic carbonate".
The cyclic carbonate having a carbon-carbon unsaturated bond is not particularly limited as long as it is a cyclic carbonate having a carbon-carbon unsaturated bond, and a carbonate having any carbon-carbon unsaturated bond can be used. In addition, the cyclic carbonate which has a substituent which has an aromatic ring shall also be included by the cyclic carbonate which has a carbon-carbon unsaturated bond. The method for producing the unsaturated cyclic carbonate is not particularly limited, and any known method can be selected for production.

Examples of unsaturated cyclic carbonates include vinylene carbonates, ethylene carbonates substituted with a substituent having an aromatic ring or a carbon-carbon unsaturated bond, phenyl carbonates, vinyl carbonates, allyl carbonates and the like.
Examples of vinylene carbonates include vinylene carbonate, methylvinylene carbonate, 4,5-dimethylvinylene carbonate, phenylvinylene carbonate, 4,5-diphenylvinylene carbonate, vinylvinylene carbonate, allylvinylene carbonate and the like.

  Specific examples of ethylene carbonates substituted with a substituent having an aromatic ring or a carbon-carbon unsaturated bond include vinyl ethylene carbonate, 4,5-divinyl ethylene carbonate, phenyl ethylene carbonate, 4,5-diphenyl ethylene carbonate, Ethynyl ethylene carbonate, 4, 5-diethynyl ethylene carbonate, etc. are mentioned.

  Among them, vinylene carbonates, ethylene carbonate substituted with a substituent having an aromatic ring or a carbon-carbon unsaturated bond are preferable, and particularly vinylene carbonate, 4,5-diphenylvinylene carbonate, 4,5-dimethylvinylene carbonate, vinyl Ethylene carbonate and ethynyl ethylene carbonate are more preferably used because they form a stable surface protective film.

  The molecular weight of the unsaturated cyclic carbonate is not particularly limited, and is arbitrary unless the effects of the present invention are significantly impaired. The molecular weight of the unsaturated cyclic carbonate is usually 50 or more, preferably 80 or more, and usually 250 or less, preferably 150 or less. Within this range, the solubility of the unsaturated cyclic carbonate in the non-aqueous electrolytic solution can be easily secured, and the effects of the present invention can be sufficiently exhibited.

The unsaturated cyclic carbonate may be used singly or in combination of two or more in any combination and ratio. Further, the content of unsaturated cyclic carbonate is not particularly limited, and is optional unless the effects of the present invention are significantly impaired. The content of unsaturated cyclic carbonate is usually 0.001% by mass or more, preferably 0.01% by mass or more, more preferably 0.1% by mass or more, in 100% by mass of the non-aqueous electrolyte solution. Preferably, it is 0.2% by mass or more, and usually 10% by mass or less, preferably 8% by mass or less, more preferably 5% by mass or less.
If it is in the said range, a non-aqueous electrolyte solution secondary battery will be easy to express sufficient high temperature storage characteristics and the cycle characteristic improvement effect.

1-3-2. Fluorinated unsaturated cyclic carbonate>
As the fluorinated cyclic carbonate, it is also preferable to use a cyclic carbonate having an unsaturated bond and a fluorine atom (hereinafter sometimes abbreviated as "fluorinated unsaturated cyclic carbonate"). The fluorinated unsaturated cyclic carbonate is not particularly limited. Among them, one or two fluorine atoms are preferable. The method for producing the fluorinated unsaturated cyclic carbonate is not particularly limited, and any known method can be selected for production.

Examples of fluorinated unsaturated cyclic carbonates include vinylene carbonate derivatives, ethylene carbonate derivatives substituted with a substituent having an aromatic ring or a carbon-carbon unsaturated bond, and the like.
Examples of vinylene carbonate derivatives include 4-fluorovinylene carbonate, 4-fluoro-5-methylvinylene carbonate, 4-fluoro-5-phenylvinylene carbonate, and 4,5-difluoroethylene carbonate.

  Examples of the ethylene carbonate derivative substituted with a substituent having an aromatic ring or a carbon-carbon unsaturated bond include 4-fluoro-4-vinylethylene carbonate, 4-fluoro-5-vinylethylene carbonate, and 4,4-difluoro-4. -Vinyl ethylene carbonate, 4,5-difluoro-4-vinyl ethylene carbonate, 4-fluoro-4,5-divinyl ethylene carbonate, 4,5-difluoro-4,5-divinyl ethylene carbonate, 4-fluoro-4-phenyl Ethylene carbonate, 4-fluoro-5-phenylethylene carbonate, 4,4-difluoro-5-phenylethylene carbonate, 4,5-difluoro-4-phenylethylene carbonate and the like can be mentioned.

  The molecular weight of the fluorinated unsaturated cyclic carbonate is not particularly limited and is arbitrary unless the effects of the present invention are significantly impaired. The molecular weight of the fluorinated unsaturated cyclic carbonate is usually 50 or more, preferably 80 or more, and usually 250 or less, preferably 150 or less. Within this range, the solubility of the fluorinated cyclic carbonate in the non-aqueous electrolyte solution can be easily ensured, and the effects of the present invention can be easily exhibited.

  The fluorinated unsaturated cyclic carbonates may be used alone or in any combination of two or more in any proportion. In addition, the blending amount of the fluorinated unsaturated cyclic carbonate is not particularly limited, and is arbitrary unless the effects of the present invention are significantly impaired. The content of the fluorinated unsaturated cyclic carbonate is usually 0.01% by mass or more, preferably 0.1% by mass or more, more preferably 0.2% by mass or more, in 100% by mass of the non-aqueous electrolytic solution. Usually, it is 5% by mass or less, preferably 4% by mass or less, more preferably 3% by mass or less. Within this range, the non-aqueous electrolyte secondary battery is likely to exhibit a sufficient improvement in cycle characteristics.

1-3-3. Cyclic sulfonic acid ester compound>
The type of cyclic sulfonic acid ester compound that can be used in the non-aqueous electrolyte solution of the present invention is not particularly limited, but a compound represented by General Formula (2) is preferable. The method for producing the cyclic sulfonic acid ester compound is not particularly limited, and any known method can be selected for production.

In the formula, R ⁵ and R ⁶ each independently represent an organic group composed of an atom selected from the group consisting of carbon atom, hydrogen atom, nitrogen atom, oxygen atom, sulfur atom, phosphorus atom and halogen atom, R ⁵ and R ⁶ may contain an unsaturated bond together with -O-SO _2- .
R ⁵ and R ⁶ are preferably an organic group composed of an atom consisting of a carbon atom, a hydrogen atom, an oxygen atom, and a sulfur atom, and among them, a hydrocarbon group having 1 to 3 carbon atoms, -O-SO It is preferable that it is an organic group which has _2- .

  The molecular weight of the cyclic sulfonic acid ester compound is not particularly limited, and is arbitrary unless the effects of the present invention are significantly impaired. The molecular weight of the cyclic sulfonic acid ester compound is usually 100 or more, preferably 110 or more, and usually 250 or less, preferably 220 or less. Within this range, the solubility of the cyclic sulfonic acid ester compound in the non-aqueous electrolyte solution can be easily ensured, and the effects of the present invention can be easily exhibited.

Specific examples of the compound represented by the general formula (2) include, for example,
1,3-propane sultone,
1-Fluoro-1,3-propane sultone,
2-fluoro-1,3-propane sultone,
3-fluoro-1,3-propane sultone,
1-methyl-1,3-propane sultone,
2-Methyl-1,3-propane sultone,
3-Methyl-1,3-propanesultone 1-propene-1,3-sultone,
2-propene-1,3-sultone,

1-Fluoro-1-propene-1,3-sultone,
2-Fluoro-1-propene-1,3-sultone,
3-fluoro-1-propene-1,3-sultone,
1-Fluoro-2-propene-1,3-sultone,
2-fluoro-2-propene-1,3-sultone,
3-fluoro-2-propene-1,3-sultone,
1-methyl-1-propene-1,3-sultone,
2-Methyl-1-propene-1,3-sultone,
3-Methyl-1-propene-1,3-sultone,
1-methyl-2-propene-1,3-sultone,
2-Methyl-2-propene-1,3-sultone,
3-Methyl-2-propene-1,3-sultone,
1,4-butane sultone,

1-Fluoro-1,4-butanesultone,
2-fluoro-1,4-butane sultone,
3-fluoro-1,4-butane sultone,
4-fluoro-1,4-butane sultone,
1-methyl-1,4-butanesultone,
2-Methyl-1,4-butanesultone,
3-Methyl-1,4-butanesultone,
4-Methyl-1,4-butanesultone,
1-butene-1,4-sultone,
2-butene-1,4-sultone,
3-butene-1,4-sultone,

1-Fluoro-1-butene-1,4-sultone,
2-fluoro-1-butene-1,4-sultone,
3-fluoro-1-butene-1,4-sultone,
4-fluoro-1-butene-1,4-sultone,
1-Fluoro-2-butene-1,4-sultone,
2-fluoro-2-butene-1,4-sultone,
3-fluoro-2-butene-1,4-sultone,
4-fluoro-2-butene-1,4-sultone,
1-Fluoro-3-butene-1,4-sultone,
2-fluoro-3-butene-1,4-sultone,
3-fluoro-3-butene-1,4-sultone,
4-fluoro-3-butene-1,4-sultone,
1-methyl-1-butene-1,4-sultone,
2-Methyl-1-butene-1,4-sultone,
3-Methyl-1-butene-1,4-sultone,
4-Methyl-1-butene-1,4-sultone,
1-methyl-2-butene-1,4-sultone,
2-Methyl-2-butene-1,4-sultone,
3-Methyl-2-butene-1,4-sultone,
4-Methyl-2-butene-1,4-sultone,
1-methyl-3-butene-1,4-sultone,
2-Methyl-3-butene-1,4-sultone,
3-Methyl-3-butene-1,4-sultone,
4-Methyl-3-butene-1,4-sultone,
1,5-pentanesultone,

1-Fluoro-1,5-pentanesultone,
2-fluoro-1,5-pentanesultone,
3-fluoro-1,5-pentanesultone,
4-fluoro-1,5-pentanesultone,
5-fluoro-1,5-pentanesultone,
1-methyl-1,5-pentanesultone,
2-Methyl-1,5-pentanesultone,
3-Methyl-1,5-pentanesultone,
4-methyl-1,5-pentanesultone,
5-methyl-1,5-pentanesultone,
1-pentene-1,5-sultone,
2-pentene-1,5-sultone,
3-pentene-1,5-sultone,
4-pentene-1,5-sultone,

1-Fluoro-1-pentene-1,5-sultone,
2-fluoro-1-pentene-1,5-sultone,
3-fluoro-1-pentene-1,5-sultone,
4-fluoro-1-pentene-1,5-sultone,
5-fluoro-1-pentene-1,5-sultone,
1-Fluoro-2-pentene-1,5-sultone,
2-fluoro-2-pentene-1,5-sultone,
3-fluoro-2-pentene-1,5-sultone,
4-fluoro-2-pentene-1,5-sultone,
5-fluoro-2-pentene-1,5-sultone,
1-Fluoro-3-pentene-1,5-sultone,
2-fluoro-3-pentene-1,5-sultone,
3-fluoro-3-pentene-1,5-sultone,
4-fluoro-3-pentene-1,5-sultone,
5-fluoro-3-pentene-1,5-sultone,
1-Fluoro-4-pentene-1,5-sultone,
2-fluoro-4-pentene-1,5-sultone,
3-fluoro-4-pentene-1,5-sultone,
4-fluoro-4-pentene-1,5-sultone,
5-fluoro-4-pentene-1,5-sultone,

1-methyl-1-pentene-1,5-sultone,
2-Methyl-1-pentene-1,5-sultone,
3-Methyl-1-pentene-1,5-sultone,
4-Methyl-1-pentene-1,5-sultone,
5-Methyl-1-pentene-1,5-sultone,
1-methyl-2-pentene-1,5-sultone,
2-Methyl-2-pentene-1,5-sultone,
3-Methyl-2-pentene-1,5-sultone,
4-Methyl-2-pentene-1,5-sultone,
5-Methyl-2-pentene-1,5-sultone,
1-methyl-3-pentene-1,5-sultone,
2-Methyl-3-pentene-1,5-sultone,
3-Methyl-3-pentene-1,5-sultone,
4-Methyl-3-pentene-1,5-sultone,
5-methyl-3-pentene-1,5-sultone,
1-methyl-4-pentene-1,5-sultone,
2-Methyl-4-pentene-1,5-sultone,
3-Methyl-4-pentene-1,5-sultone,
4-Methyl-4-pentene-1,5-sultone,
Sultone compounds such as 5-methyl-4-pentene-1,5-sultone;

Methylene sulfate,
Ethylene sulfate,
Sulfate compounds such as propylene sulfate;
Methylene methane disulfonate,
Disulfonate compounds such as ethylene methane disulfonate;

1,2,3-oxathiazolidine-2,2-dioxide,
3-Methyl-1,2,3-oxathiazolidine-2,2-dioxide,
3H-1,2,3-oxathiazole-2,2-dioxide,
5H-1,2,3-oxathiazole-2,2-dioxide,
1,2,4-oxathiazolidine-2,2-dioxide,
4-methyl-1,2,4-oxathiazolidine-2,2-dioxide,
3H-1,2,4-oxathiazole-2,2-dioxide,
5H-1,2,4-oxathiazole-2,2-dioxide,
1,2,5-oxathiazolidine-2,2-dioxide,
5-Methyl-1,2,5-oxathiazolidine-2,2-dioxide,
3H-1,2,5-oxathiazole-2,2-dioxide,
5H-1,2,5-oxathiazole-2,2-dioxide,
1,2,3-oxathiadinan-2,2-dioxide,
3-Methyl-1,2,3-oxathiazinan-2,2-dioxide,
5,6-dihydro-1,2,3-oxathiazine-2,2-dioxide,
1,2,4-oxathiadinan-2,2-dioxide,

4-methyl-1,2,4-oxathiazinan-2,2-dioxide,
5,6-dihydro-1,2,4-oxathiazine-2,2-dioxide,
3,6-dihydro-1,2,4-oxathiazine-2,2-dioxide,
3,4-dihydro-1,2,4-oxathiazine-2,2-dioxide,
1,2,5-oxathiadinan-2,2-dioxide,
5-Methyl-1,2,5-oxathiazinan-2,2-dioxide,
5,6-dihydro-1,2,5-oxathiazine-2,2-dioxide,
3,6-dihydro-1,2,5-oxathiazine-2,2-dioxide,
3,4-dihydro-1,2,5-oxathiazine-2,2-dioxide,
1,2,6-oxathiadinan-2,2-dioxide,
6-Methyl-1,2,6-oxathiazinan-2,2-dioxide,
5,6-dihydro-1,2,6-oxathiazine-2,2-dioxide,
3,4-dihydro-1,2,6-oxathiazine-2,2-dioxide,
Nitrogen-containing compounds such as 5,6-dihydro-1,2,6-oxathiazine-2,2-dioxide;

1,2,3-oxathiaphoslane-2,2-dioxide,
3-Methyl-1,2,3-oxathiaphoslane-2,2-dioxide,
3-Methyl-1,2,3-oxathiaphoslane-2,2,3-trioxide,
3-methoxy-1,2,3-oxathiaphoslane-2,2,3-trioxide,
1,2,4-oxathiaphoslane-2,2-dioxide,
4-methyl-1,2,4-oxathiaphoslane-2,2-dioxide,
4-methyl-1,2,4-oxathiaphoslane-2,2,4-trioxide,
4-methoxy-1,2,4-oxathiaphoslane-2,2,4-trioxide,
1,2,5-oxathiaphoslane-2,2-dioxide,
5-methyl-1,2,5-oxathiaphoslane-2,2-dioxide,
5-methyl-1,2,5-oxathiaphoslane-2,2,5-trioxide,
5-methoxy-1,2,5-oxathiaphoslane-2,2,5-trioxide,
1,2,3-oxathiaphosphinan-2,2-dioxide,
3-Methyl-1,2,3-oxathiaphosphinan-2,2-dioxide,
3-Methyl-1,2,3-oxathiaphosphinan-2,2,3-trioxide,
3-methoxy-1,2,3-oxathiaphosphinan-2,2,3-trioxide,

1,2,4-oxathiaphosphinan-2,2-dioxide,
4-Methyl-1,2,4-oxathiaphosphinan-2,2-dioxide,
4-methyl-1,2,4-oxathiaphosphinan-2,2,3-trioxide,
4-Methyl-1,5,2,4-dioxathiaphosphinan-2,4-dioxide,
4-methoxy-1,5,2,4-dioxathiaphosphinan-2,4-dioxide,
3-methoxy-1,2,4-oxathiaphosphinan-2,2,3-trioxide,
1,2,5-oxathiaphosphinan-2,2-dioxide,
5-Methyl-1,2,5-oxathiaphosphinan-2,2-dioxide,
5-methyl-1,2,5-oxathiaphosphinan-2,2,3-trioxide,
5-methoxy-1,2,5-oxathiaphosphinan-2,2,3-trioxide,
1,2,6-oxathiaphosphinan-2,2-dioxide,
6-Methyl-1,2,6-oxathiaphosphinan-2,2-dioxide,
6-Methyl-1,2,6-oxathiaphosphinan-2,2,3-trioxide,
6-methoxy-1,2,6-oxathiaphosphinan-2,2,3-trioxide which phosphorus-containing compound;

Of these,
1,3-propane sultone, 1-fluoro-1,3-propane sultone, 2-fluoro-1,3-propane sultone, 3-fluoro-1,3-propane sultone, 1-propene-1,3-sultone, 1-Fluoro-1-propene-1,3-sultone, 2-fluoro-1-propene-1,3-sultone, 3-fluoro-1-propene-1,3-sultone, 1,4-butane sultone, methylene methane Disulfonate and ethylene methanedisulfonate are preferable from the viewpoint of improving storage characteristics, and 1,3-propane sultone, 1-fluoro-1,3-propane sultone, 2-fluoro-1,3-propane sultone, 3-fluoro-1 , 3-propane sultone and 1-propene-1,3-sultone are more preferable.

  The cyclic sulfonic acid ester compounds may be used alone or in any combination and ratio of two or more. There is no restriction | limiting in the compounding quantity of a cyclic sulfonic acid ester compound with respect to the whole non-aqueous electrolyte solution of this invention, Although it is arbitrary unless the effect of this invention is impaired remarkably, Usually with respect to the non-aqueous electrolyte of this invention. 001 mass% or more, preferably 0.01 mass% or more, more preferably 0.1 mass% or more, further preferably 0.3 mass% or more, and usually 10 mass% or less, preferably 5 mass% or less, more Preferably, it is contained at a concentration of 3% by mass or less. When the above range is satisfied, effects such as input / output characteristics, charge / discharge rate characteristics, cycle characteristics, high temperature storage characteristics and the like are further improved.

1-3-4. Compound having a cyano group>
The type of the compound having a cyano group that can be used in the non-aqueous electrolyte solution of the present invention is not particularly limited as long as it is a compound having a cyano group in the molecule, but the compound is not limited thereto. Compounds are more preferred. The method for producing the compound having a cyano group is not particularly limited, and any known method can be selected for production.

(Wherein, T represents an organic group composed of an atom selected from the group consisting of carbon atom, hydrogen atom, nitrogen atom, oxygen atom, sulfur atom, phosphorus atom and halogen atom, and U has a substituent And may be a V-valent organic group having a carbon number of 1 to 10. V is an integer of 1 or more, and when V is 2 or more, T may be the same as or different from each other)

The molecular weight of the compound having a cyano group is not particularly limited, and is arbitrary unless the effects of the present invention are significantly impaired. The molecular weight of the compound having a cyano group is usually 40 or more, preferably 45 or more, more preferably 50 or more, and usually 200 or less, preferably 180 or less, more preferably 170 or less. Within this range, the solubility of the compound having a cyano group in the non-aqueous electrolyte solution can be easily ensured, and the effects of the present invention can be easily exhibited.

As a specific example of the compound represented by General formula (3), for example,
Acetonitrile,
Propionitrile,
Butyronitrile,
Isobutyronitrile,
Valeronitrile,
Isovaleronitrile,
Lauronitrile 2-methylbutyronitrile,
Trimethyl acetonitrile,
Hexane nitrile,
Cyclopentanecarbonitrile,
Cyclohexanecarbonitrile,
Acrylonitrile,
Methacrylonitrile,
Crotononitrile,

3-Methylcrotononitrile,
2-Methyl-2-buteneditolyl,
2-pentene nitrile,
2-Methyl-2-pentenenitrile,
3-Methyl-2-pentenenitrile,
2-hexene nitrile,
Fluoroacetonitrile,
Difluoroacetonitrile,
Trifluoroacetonitrile,
2-fluoropropionitrile,
3-fluoropropionitrile,
2, 2-difluoropropionitrile,
2,3-difluoropropionitrile,
2,3-difluoropropionitrile,
2,2,3-trifluoropropionitrile,
3,3,3-trifluoropropionitrile,
3,3'-oxydipropionitrile,
3,3'-thiodipropionitrile,
1,2,3-propanetricarbonitrile,
1,3,5-pentanetricarbonitrile,
A compound having one cyano group such as pentafluoropropionitrile;

Malononitrile,
Succinonitrile,
Glutaronitrile,
Adiponitrile,
Pimeronitrile,
Suberonitrile,
Azera nitrile,
Sebaconitrile,
Undecane dinitrile,
Dodecane dinitrile,
Methyl malononitrile,
Ethyl malononitrile,

Isopropyl malononitrile,
tert-butyl malononitrile,
Methyl succinonitrile,
2,2-dimethyl succinonitrile,
2,3-dimethyl succinonitrile,
Trimethyl succinonitrile,
Tetramethyl succinonitrile 3,3 '-(ethylenedioxy) dipropionitrile,
Compounds having two cyano groups such as 3,3 '-(ethylenedithio) dipropionitrile;

1,2,3-tris (2-cyanoethoxy) propane,
Compounds having three cyano groups such as tris (2-cyanoethyl) amine;
Methyl cyanate,
Ethyl cyanate,
Propyl cyanate,
Butyl cyanate,
Pentyl cyanate,
Hexyl cyanate,
Cyanate compounds such as heptyl cyanate;

Methyl thiocyanate,
Ethyl thiocyanate,
Propyl thiocyanate,
Butyl thiocyanate,
Pentyl thiocyanate,
Hexyl thiocyanate,
Heptyl thiocyanate,
Methanesulfonyl cyanide,
Ethanesulfonyl cyanide,
Propane sulfonyl cyanide,
Butan sulfonyl cyanide,
Pentanesulfonyl cyanide,
Hexane sulfonyl cyanide,
Heptane sulfonyl cyanide,
Sulfur-containing compounds such as methyl sulfo sia nidate ethyl sulf sia ni date propyl sulf sia ni date butyl sulf sia ni date pentyl sulf sia ni dat hexyl sulf sia ni dat heptyl sulf sia ni dayt;

Cyanodimethyl phosphine cyano dimethyl phosphine oxide cyano methyl phosphinate methyl cyano methyl phosphino acid dimethyl phosphinic acid dimethyl phosphinic acid cyanide dimethyl phosphinic acid cyanide cyano phosphonic acid dimethyl cyanophosphorous acid dimethyl methyl phosphonic acid cyanomethyl methyl phosphonic acid cyanomethyl phosphoric acid cyanomethyl phosphoric acid Phosphorus-containing compounds such as cyanodimethyl phosphite cyanodimethyl phosphite;
Etc.

Of these,
Acetonitrile, propionitrile, butyronitrile, isobutyronitrile, valeronitrile, isovaleronitrile, lauronitrile, crotononitrile, 3-methyl crotononitrile, malononitrile, succinonitrile, glutaronitrile, adiponitrile, pimeronitrile, suberonitrile, Azera nitrile, sebaconitrile, undecane dinitrile, dodecane dinitrile is preferable from the viewpoint of improving storage characteristics, and cyano such as malononitrile, succinonitrile, glutaronitrile, adiponitrile, pimeronitrile, suberonitrile, azela nitrile, sebaconitrile, undecane dinitrile, dodecane dinitrile, etc. Compounds having two groups are more preferred.

  The compound having a cyano group may be used alone or in combination of two or more in any combination and ratio. The content of the compound having a cyano group with respect to the whole non-aqueous electrolyte of the present invention is not limited, and is optional unless the effects of the present invention are significantly impaired. 001 mass% or more, preferably 0.01 mass% or more, more preferably 0.1 mass% or more, further preferably 0.3 mass% or more, and usually 10 mass% or less, preferably 5 mass% or less, more Preferably, it is contained at a concentration of 3% by mass or less. When the above range is satisfied, effects such as input / output characteristics, charge / discharge rate characteristics, cycle characteristics, high temperature storage characteristics and the like are further improved.

1-3-5. Diisocyanate compound>
In the non-aqueous electrolytic solution of the present invention, the diisocyanate compound which can be used is not particularly limited as long as it is a compound having two isocyanato groups in the molecule, but a compound represented by the following general formula (4) is preferable.

(Wherein, X is a hydrocarbon group having 1 to 16 carbon atoms which may be substituted with fluorine)
In the said General formula (4), X is a C1-C16 hydrocarbon group which may be substituted by the fluorine. The carbon number of X is usually 2 or more, preferably 3 or more, more preferably 4 or more, and usually 14 or less, preferably 12 or less, more preferably 10 or less, and most preferably 8 or less. The type of X is not particularly limited as long as it is a hydrocarbon group. Although any of an aliphatic chain alkylene group, an aliphatic cyclic alkylene group and an aromatic ring-containing hydrocarbon group may be used, an aliphatic chain alkylene group or an aliphatic cyclic alkylene group is preferable.

As a specific example of the diisocyanate in the present invention,
Linear polymethylene diisocyanates such as ethylene diisocyanate, trimethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, heptamethylene diisocyanate, octamethylene diisocyanate, decamethylene diisocyanate, dodecamethylene diisocyanate, tetradecamethylene diisocyanate, etc .; methyl Tetramethylene diisocyanate, dimethyltetramethylene diisocyanate, trimethyltetramethylene diisocyanate, methylhexamethylene diisocyanate, dimethylhexamethylene diisocyanate, trimethylhexamethylene diisocyanate, methyloctamethylene diisocyanate, dimethyloctamethylene diisocyanate 1, 4-diisocyanato-2-butene, 1,5-diisocyanato-2-pentene, 1,5-diisocyanato-3-pentene, 1,6-diisocyanato-, and the like. Diisocyanatoalkenes such as 2-hexene, 1,6-diisocyanato-3-hexene, 1,8-diisocyanato-2-octene, 1,8-diisocyanato-3-octene, 1,8-diisocyanato-4-octene, etc. 1,3-diisocyanato-2-fluoropropane, 1,3-diisocyanato-2,2-difluoropropane, 1,4-diisocyanato-2-fluorobutane, 1,4-diisocyanato-2,2-difluorobutane, 1,4-diisocyanato-2,3-difluorobutane, 1,6 Diisocyanato-2-fluorohexane, 1,6-diisocyanato-3-fluorohexane, 1,6-diisocyanato-2,2-difluorohexane, 1,6-diisocyanato-2,3-difluorohexane, 1,6-diisocyanato- 2,4-Difluorohexane, 1,6-diisocyanato-2,5-difluorohexane, 1,6-diisocyanato-3,3-difluorohexane, 1,6-diisocyanato-3,4-difluorohexane, 1,8- Diisocyanato-2-fluorooctane, 1,8-diisocyanato-3-fluorooctane, 1,8-diisocyanato-4-fluorooctane, 1,8-diisocyanato-2,2-difluorooctane, 1,8-diisocyanato-2,2, 3-difluorooctane, 1,8-diisocyanato-2, Fluorine-substituted diisocyanates such as 4-difluorooctane, 1,8-diisocyanato-2,5-difluorooctane, 1,8-diisocyanato-2,6-difluorooctane, 1,8-diisocyanato-2,7-difluorooctane, etc. Natoalkanes; 1,2-diisocyanatocyclopentane, 1,3-diisocyanatocyclopentane, 1,2-diisocyanatocyclohexane, 1,3-diisocyanatocyclohexane, 1,4-diisocyanatocyclohexane 1,2-bis (isocyanatomethyl) cyclohexane, 1,3-bis (isocyanatomethyl) cyclohexane, 1,4-bis (isocyanatomethyl) cyclohexane, dicyclohexylmethane-2,2′-diisocyanate, dicyclohexylmethane- 2,4'-diisocyanate, disse Cycloalkane ring-containing diisocyanates such as lohexylmethane-3,3'-diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, etc .; 1,2-phenylene diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate , Tolylene-2,3-diisocyanate, tolylene-2,4-diisocyanate, tolylene-2,5-diisocyanate, tolylene-2,6-diisocyanate, tolylene-3,4-diisocyanate, tolylene-3,5-diisocyanate, 1 , 2-Bis (isocyanatomethyl) benzene, 1,3-bis (isocyanatomethyl) benzene, 1,4-bis (isocyanatomethyl) benzene, 2,4-diisocyanatobiphenyl, 2,6-diisocyanate Natobiphenyl, 2 2'-diisocyanatobiphenyl, 3,3'-diisocyanatobiphenyl, 4,4'-diisocyanato-2-methylbiphenyl, 4,4'-diisocyanato-3-methylbiphenyl, 4,4'-diisocyanato-3 , 3'-dimethylbiphenyl, 4,4'-diisocyanatodiphenylmethane, 4,4'-diisocyanato-2-methyldiphenylmethane, 4,4'-diisocyanato-3-methyldiphenylmethane, 4,4'-diisocyanato-3, 3'-Dimethyldiphenylmethane, 1,5-diisocyanatonaphthalene, 1,8-diisocyanatonaphthalene, 2,3-diisocyanatonaphthalene, 1,5-bis (isocyanatomethyl) naphthalene, 1,8-bis Aromatic rings such as (isocyanatomethyl) naphthalene and 2,3-bis (isocyanatomethyl) naphthalene Containing diisocyanates;
Etc.

Among these,
Linear polymethylene diisocyanates such as ethylene diisocyanate, trimethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, heptamethylene diisocyanate, octamethylene diisocyanate, decamethylene diisocyanate, dodecamethylene diisocyanate, tetradecamethylene diisocyanate, etc .; methyl Tetramethylene diisocyanate, dimethyltetramethylene diisocyanate, trimethyltetramethylene diisocyanate, methylhexamethylene diisocyanate, dimethylhexamethylene diisocyanate, trimethylhexamethylene diisocyanate, methyloctamethylene diisocyanate, dimethyloctamethylene diisocyanate Branched, alkylene diisocyanates such as trimethyloctamethylene diisocyanate; 1,2-diisocyanatocyclopentane, 1,3-diisocyanatocyclopentane, 1,2-diisocyanatocyclohexane, 1,3-diisocyanato Cyclohexane, 1,4-diisocyanatocyclohexane, 1,2-bis (isocyanatomethyl) cyclohexane, 1,3-bis (isocyanatomethyl) cyclohexane, 1,4-bis (isocyanatomethyl) cyclohexane, dicyclohexylmethane- Cycloalkane ring-containing diisocyanates such as 2,2'-diisocyanate, dicyclohexylmethane-2,4'-diisocyanate, dicyclohexylmethane-3,3'-diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, etc. Kind;
Is preferred.

Moreover,
Linear polymethylene diisocyanates selected from tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, heptamethylene diisocyanate, octamethylene diisocyanate; 1,2-diisocyanatocyclopentane, 1,3-diisocyanatocyclopentane, 1,2-diisocyanatocyclohexane, 1,3-diisocyanatocyclohexane, 1,4-diisocyanatocyclohexane, 1,2-bis (isocyanatomethyl) cyclohexane, 1,3-bis (isocyanatomethyl) cyclohexane , 4-bis (isocyanatomethyl) cyclohexane, dicyclohexylmethane-2,2'-diisocyanate, dicyclohexylmethane-2,4'-diisocyanate, dicyclohexylmethane 3,3'-diisocyanate, cycloalkane ring containing diisocyanates selected from dicyclohexylmethane-4,4'-diisocyanate;
Is particularly preferred.

The diisocyanates in the present invention described above may be used alone or in any combination of two or more in any proportion.
The content of diisocyanate which can be used in the non-aqueous electrolyte solution of the present invention is not particularly limited and is optional as long as the effects of the present invention are not significantly impaired, but relative to the total mass of the non-aqueous electrolyte solution Usually, 0.001% by mass or more, preferably 0.01% by mass or more, more preferably 0.1% by mass or more, still more preferably 0.3% by mass or more, and usually 5% by mass or less, preferably 4% by mass The following content is more preferably 3% by mass or less, further preferably 2% by mass or less. When the content is within the above range, the durability of the cycle, storage and the like can be improved, and the effects of the present invention can be sufficiently exhibited.

1-3-6. Overcharge inhibitor>
In the non-aqueous electrolyte solution of the present invention, an anti-overcharge agent can be used in order to effectively suppress battery rupture and ignition when the non-aqueous electrolyte secondary battery is in a state of overcharge and the like. .
As the overcharge inhibitor, biphenyl, alkylbiphenyl, terphenyl, a partially hydrogenated terphenyl, cyclohexylbenzene, t-butylbenzene, t-amylbenzene, diphenylether, dibenzofuran, diphenylcyclohexane, 1,1,3-trimethyl Aromatic compounds such as -3-phenylindane; partial fluorinated compounds of the above aromatic compounds such as 2-fluorobiphenyl, o-cyclohexylfluorobenzene, p-cyclohexylfluorobenzene and the like; 2,4-difluoroanisole, 2,5-difluoro Fluorine-containing anisole compounds such as anisole, 2,6-difluoroanisole, 3,5-difluoroanisole and the like; 3-propylphenyl acetate, 2-ethylphenyl acetate, benzylphenyl acetate, methyl phenyl Le acetate, benzyl acetate, aromatic acetates such as phenethyl phenylacetate; diphenyl carbonate, and aromatic carbonates such as methyl phenyl carbonate. Among them, biphenyl, alkylbiphenyl, terphenyl, partially hydrogenated terphenyl, cyclohexylbenzene, t-butylbenzene, t-amylbenzene, diphenylether, dibenzofuran, diphenylcyclohexane, 1,1,3-trimethyl-3-phenylindan 3-Propyl phenyl acetate, 2-ethyl phenyl acetate, benzyl phenyl acetate, methyl phenyl acetate, benzyl acetate, phenethyl phenyl acetate, diphenyl carbonate and methyl phenyl carbonate are preferable. These may be used alone or in combination of two or more. When two or more kinds are used in combination, in particular, a combination of cyclohexylbenzene and t-butylbenzene or t-amylbenzene, biphenyl, alkylbiphenyl, terphenyl, a partially hydrogenated terphenyl, cyclohexylbenzene, t-butylbenzene, The combined use of at least one selected from an oxygen-free aromatic compound such as t-amylbenzene and at least one selected from an oxygen-containing aromatic compound such as diphenyl ether and dibenzofuran is an overcharge preventing property and a high temperature storage characteristic It is preferable from the point of balance of

  The content of the overcharge inhibitor is not particularly limited, and is optional as long as the effects of the present invention are not significantly impaired. The content of the overcharge inhibitor is usually 0.1% by mass or more, preferably 0.2% by mass or more, more preferably 0.3% by mass or more, particularly preferably 0. It is 5% by mass or more, and is usually 5% by mass or less, preferably 4.8% by mass or less, more preferably 4.5% by mass or less. Within this range, the effect of the overcharge preventing agent can be easily exhibited sufficiently, and the battery characteristics such as high temperature storage characteristics can be improved.

1-3-7. Other adjuvants>
Other known auxiliary agents can be used in the non-aqueous electrolyte solution of the present invention. Other assistants include carbonate compounds such as erythritan carbonate, spiro-bis-dimethylene carbonate, methoxyethyl-methyl carbonate, etc .; 2,4,8,10-tetraoxaspiro [5.5] undecane, 3,9 Spiro compounds such as divinyl-2,4,8,10-tetraoxaspiro [5.5] undecane; ethylene sulfite, methyl fluorosulfonate, ethyl fluorosulfonate, methyl methanesulfonate, ethyl methanesulfonate, busulfan -Containing compounds such as sulfolene, ethylene sulfate, vinylene sulfate, diphenyl sulfone, N, N-dimethyl methane sulfonamide, N, N-diethyl methane sulfonamide; 1-methyl-2-pyrrolidinone, 1-methyl-2-piperidone , 3-methyl-2-oxazolate Nitrogen-containing compounds such as nonone, 1,3-dimethyl-2-imidazolidinone and N-methylsuccinimide; hydrocarbon compounds such as heptane, octane, nonane, decane and cycloheptane, fluorobenzene, difluorobenzene, hexafluorobenzene, Fluorine-containing aromatic compounds such as benzotrifluoride; tris (trimethylsilyl) borate, tris (trimethoxysilyl) borate, tris (trimethylsilyl) phosphate, tris (trimethoxysilyl) phosphate, dimethoxyaluminoxytrimethoxysilane, Diethoxyaluminoxytriethoxysilane, dipropoxyaluminoxytriethoxysilane, dibutoxyaluminoxytrimethoxysilane, dibutoxyaluminoxytriethoxysilane, titanium tetrakis (trimethylsiloxide), Silane compounds such as Tantetorakisu (triethyl siloxide), and the like. These may be used alone or in combination of two or more. By adding these assistants, capacity retention characteristics and cycle characteristics after high temperature storage can be improved.

  The content of the other auxiliaries is not particularly limited, and is optional unless the effects of the present invention are significantly impaired. The content of the other auxiliary agent is usually 0.01% by mass or more, preferably 0.1% by mass or more, more preferably 0.2% by mass or more, in 100% by mass of the non-aqueous electrolytic solution. It is 5% by mass or less, preferably 3% by mass or less, more preferably 1% by mass or less. Within this range, the effects of the other auxiliary agents are easily exhibited, and the battery characteristics such as high load discharge characteristics are improved.

  The non-aqueous electrolytic solution described above includes those existing inside the non-aqueous electrolytic solution battery described in the present invention. Specifically, components of the non-aqueous electrolytic solution such as a lithium salt, a solvent, and an auxiliary agent are separately synthesized, and the non-aqueous electrolytic solution is prepared from those substantially isolated, and the method described below is used. In the case of a non-aqueous electrolytic solution in a non-aqueous electrolytic solution battery obtained by pouring into a separately assembled battery, or the components of the non-aqueous electrolytic solution of the present invention are individually put in the battery, When the same composition as the non-aqueous electrolyte solution of the present invention is obtained by mixing at the same time, a compound constituting the non-aqueous electrolyte solution of the present invention is generated in the non-aqueous electrolyte solution battery. The case where the same composition as the aqueous electrolyte solution is obtained is also included.

<2. Non-aqueous electrolyte secondary battery>
The non-aqueous electrolyte secondary battery of the present invention comprises a negative electrode and a positive electrode capable of absorbing and desorbing ions, and the above-mentioned non-aqueous electrolyte of the present invention.

<2-1. Battery configuration>
The non-aqueous electrolyte secondary battery of the present invention is the same as the conventionally known non-aqueous electrolyte secondary battery except for the negative electrode and the non-aqueous electrolyte, and the non-aqueous electrolyte of the present invention is usually The positive electrode and the negative electrode are stacked via a porous membrane (separator) impregnated, and they are housed in a case (exterior body). Therefore, the shape of the non-aqueous electrolyte secondary battery of the present invention is not particularly limited, and may be any of cylindrical, square, laminate, coin, large size and the like.

2-2. Non-aqueous electrolyte>
As the non-aqueous electrolytic solution, the above-mentioned non-aqueous electrolytic solution of the present invention is used. In addition, it is also possible to mix | blend and use another non-aqueous electrolyte solution with respect to the non-aqueous electrolyte solution of this invention in the range which does not deviate from the meaning of this invention.

<2-3. Negative electrode>
The negative electrode has a negative electrode active material layer on a current collector, and the negative electrode active material will be described below.
The negative electrode active material is not particularly limited as long as it can electrochemically store and release lithium ions. Specific examples thereof include carbonaceous materials, metal alloy materials, lithium-containing metal composite oxide materials, and the like. One of these may be used alone, or two or more of these may be used in combination as desired.

<2-3-1. Carbonaceous material>
As a carbonaceous material used as a negative electrode active material,
(1) Natural graphite,
(2) Carbonaceous materials obtained by heat-treating artificial carbonaceous substances and artificial graphitic substances at a temperature in the range of 400 to 3200 ° C. once or more,
(3) A carbonaceous material in which the negative electrode active material layer is made of at least two or more different crystalline carbonaceous materials and / or has an interface in which the different crystalline carbonaceous materials are in contact with each other
(4) A carbonaceous material in which the negative electrode active material layer is composed of at least two or more different orientations of carbonaceous matter and / or has an interface in which the different orientational carbonaceous matter contacts
The balance among initial irreversible capacity and high current density charge / discharge characteristics is preferable. Moreover, the carbonaceous material of (1)-(4) may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.

  Specific examples of the artificial carbonaceous material and the artificial graphitic material in the above (2) include natural graphite, coal-based coke, petroleum-based coke, coal-based pitch, petroleum-based pitch, and those obtained by oxidizing these pitches, Needle coke, pitch coke and carbon materials partially graphitized thereof, furnace black, acetylene black, pyrolysis products of organic substances such as pitch carbon fibers, carbonizable organic substances, and carbides of these or carbonizable organic substances A solution dissolved in a low molecular weight organic solvent such as benzene, toluene, xylene, quinoline, n-hexane and the like, and carbides thereof and the like can be mentioned.

2-3-2. Configuration, physical properties, preparation method of carbonaceous negative electrode>
A property of a carbonaceous material, an anode electrode containing the carbonaceous material and an electrode forming method, a current collector, and a non-aqueous electrolyte secondary battery, any one of the following (1) to (13) or It is desirable to satisfy multiple terms simultaneously.

(1) X-ray parameter The d value (interlayer distance) of the lattice plane (002 plane) determined by X-ray diffraction of the carbonaceous material by X-ray diffraction is usually 0.335 to 0.340 nm, particularly 0.335 Those having a diameter of -0.338 nm, particularly 0.335 to 0.337 nm are preferred. The crystallite size (Lc) determined by X-ray diffraction by the Gakushin method is usually 1.0 nm or more, preferably 1.5 nm or more, and particularly preferably 2 nm or more.

(2) Volume-Based Average Particle Size The volume-based average particle size of the carbonaceous material is usually 1 μm or more, preferably 3 μm or more, as the volume-based average particle size determined by laser diffraction / scattering method. 5 μm or more is more preferable, 7 μm or more is particularly preferable, and usually 100 μm or less, 50 μm or less is preferable, 40 μm or less is more preferable, 30 μm or less is more preferable, 25 μm or less is particularly preferable.
In the measurement of the volume-based average particle size, a carbon powder is dispersed in a 0.2 mass% aqueous solution (about 10 mL) of polyoxyethylene (20) sorbitan monolaurate which is a surfactant, and laser diffraction / scattering type particle size distribution Measurement is performed using a scale (LA-700 manufactured by Horiba, Ltd.). The median diameter determined by the measurement is defined as the volume-based average particle size of the carbonaceous material of the present invention.

(3) Raman R value, Raman half value width The Raman R value of the carbonaceous material is usually 0.01 or more, preferably 0.03 or more, as measured using argon ion laser Raman spectroscopy. One or more is more preferable, and usually 1.5 or less, 1.2 or less is preferable, 1 or less is more preferable, and 0.5 or less is particularly preferable.
When the Raman R value is below the above range, the crystallinity of the particle surface may be too high, and the sites at which Li may enter into the layer may decrease as charge and discharge occur. That is, the chargeability may decrease. In addition, when the negative electrode is densified by pressing after being applied to the current collector, crystals may be easily oriented in a direction parallel to the electrode plate, which may lead to a decrease in load characteristics. On the other hand, if the above range is exceeded, the crystallinity of the particle surface may be reduced, the reactivity with the non-aqueous electrolyte solution may be increased, and the efficiency may be decreased or gas generation may be increased.

The Raman half value width in the vicinity of 1580 cm ^{-1 of the} carbonaceous material is not particularly limited, but is usually 10 cm ^-1 or more, preferably 15 cm ^-1 or more, and usually 100 cm ^-1 or less, 80 cm ^-1 or less Preferably, 60 cm ⁻¹ or less is more preferable, and 40 cm ⁻¹ or less is particularly preferable.
When the Raman half width is below the above range, the crystallinity of the particle surface becomes too high, and there may be a decrease in sites where Li enters an interlayer during charge and discharge. That is, the chargeability may decrease. In addition, when the negative electrode is densified by pressing after being applied to the current collector, crystals may be easily oriented in a direction parallel to the electrode plate, which may lead to a decrease in load characteristics. On the other hand, if the above range is exceeded, the crystallinity of the particle surface may be reduced, the reactivity with the non-aqueous electrolyte solution may be increased, and the efficiency may be decreased or gas generation may be increased.

The measurement of the Raman spectrum is carried out by naturally dropping the sample into the measuring cell and filling it using a Raman spectrometer (Raman spectrometer manufactured by JASCO), and irradiating the sample surface in the cell with argon ion laser light, It is performed by rotating the cell in a plane perpendicular to the laser light. The resulting Raman spectrum, the intensity IA of a peak PA around 1580 cm ^-1, and measuring the intensity IB of the peak PB around 1360 cm ^-1, and calculates the intensity ratio R (R = IB / IA) . The Raman R value calculated by the measurement is defined as the Raman R value of the carbonaceous material in the present invention. Further, the half width of the peak PA around 1580 cm ⁻¹ of the obtained Raman spectrum is measured, and this is defined as the Raman half width of the carbonaceous material in the present invention.

Moreover, said Raman measurement conditions are as follows.
・ Argon ion laser wavelength: 514.5 nm
・ Laser power on sample: 15 to 25 mW
-Resolution: 10 to 20 cm ^-1
・ Measurement range: 1100 cm ^{-1 to} 1730 cm ^-1
・ Raman R value, Raman half width analysis: background processing
・ Smoothing processing: Simple average, convolution 5 points

(4) BET specific surface area The BET specific surface area of the carbonaceous material is usually 0.1 m ² · g ^-1 or more, 0.7 m ² · g ^-1 or more of the specific surface area measured using the BET method. Is more preferably 1.0 m ² · g ^-1 or more, particularly preferably 1.5 m ² · g ^-1 or more, and usually 100 m ² · g ^-1 or less, and 25 m ² · g ^-1 or less. Preferably, 15 m ² · g ^-1 or less is more preferable, and 10 m ² · g ^-1 or less is particularly preferable.

  When the value of the BET specific surface area falls below this range, the acceptability of lithium at the time of charging when used as a negative electrode material tends to be poor, lithium is likely to be deposited on the electrode surface, and the stability may be reduced. On the other hand, if it exceeds this range, the reactivity with the non-aqueous electrolyte solution increases when used as a negative electrode material, gas generation tends to be large, and a preferable battery may be difficult to obtain.

  Measurement of the specific surface area by the BET method is carried out by using a surface area meter (total surface area measurement device manufactured by Okura Riken) and predrying the sample under flowing nitrogen at 350 ° C. for 15 minutes and then using nitrogen of atmospheric pressure. It is carried out by the nitrogen adsorption BET one-point method according to the gas flow method, using a nitrogen-helium mixed gas which is accurately adjusted so that the value of the relative pressure is 0.3. The specific surface area determined by the measurement is defined as the BET specific surface area of the carbonaceous material in the present invention.

(5) Degree of Circularity When the degree of circularity is measured as the degree of spherical shape of the carbonaceous material, it is preferable to fall within the following range. The circularity is defined as "circularity = (peripheral length of equivalent circle having the same area as the particle projection shape) / (actual peripheral length of the particle projection shape)", and when the circularity is 1, it is theoretical It becomes a true sphere.
The circularity of particles having a particle diameter of the carbonaceous material in the range of 3 to 40 μm is preferably as close to 1 as possible, preferably 0.1 or more, more preferably 0.5 or more, and more preferably 0.8 or more. 0.85 or more is more preferable, and 0.9 or more is especially preferable.

The high current density charge / discharge characteristics improve as the degree of circularity increases. Therefore, when the circularity is less than the above range, the filling property of the negative electrode active material may be reduced, the resistance between particles may be increased, and the high current density charge / discharge characteristics may be deteriorated for a short time.
The measurement of the degree of circularity is performed using a flow type particle image analyzer (FPIA manufactured by Sysmex Corporation). About 0.2 g of a sample is dispersed in a 0.2 mass% aqueous solution (about 50 mL) of polyoxyethylene (20) sorbitan monolaurate which is a surfactant, and irradiated with ultrasonic waves of 28 kHz for 1 minute at a power of 60 W The detection range is specified to 0.6 to 400 μm, and measurement is performed on particles having a particle size in the range of 3 to 40 μm. The degree of circularity determined by the measurement is defined as the degree of circularity of the carbonaceous material in the present invention.

  The method for improving the degree of circularity is not particularly limited, but it is preferable to use a sphericizing treatment to make it spherical since the shape of the interparticle voids when the electrode body is formed is completed. As an example of the spheroidizing process, a mechanical force or a mechanical processing method in which a plurality of fine particles are granulated by a binder or the adhesive force of the particles themselves, etc. Can be mentioned.

(6) Tap density The tap density of the carbonaceous material is usually 0.1 g · cm ⁻³ or more, preferably 0.5 g · cm ⁻³ or more, more preferably 0.7 g · cm ⁻³ or more, and 1 g · Particularly, cm ³ or more is preferable, 2 g · cm ³ or less is preferable, 1.8 g · cm ³ or less is more preferable, and 1.6 g · cm ³ or less is particularly preferable.

When the tap density is lower than the above range, the packing density may not be easily increased when used as a negative electrode, and a high capacity battery may not be obtained. Moreover, when the said range is exceeded, the space | gap between particle | grains in an electrode will decrease too much, it will become difficult to ensure the conductivity between particle | grains, and it may be difficult to acquire a preferable battery characteristic.
The tap density is measured by passing the sample through a 300 μm mesh screen and dropping the sample into a 20 cm ³ tapping cell to fill the sample to the top end face of the cell, and then using a powder density measuring instrument (eg, Seishin Enterprise Co., Ltd.) Tap tapping is performed 1000 times using a stroke length of 10 mm, and the tap density is calculated from the volume at that time and the mass of the sample. The tap density calculated by the measurement is defined as the tap density of the carbonaceous material in the present invention.

(7) Orientation ratio The orientation ratio of the carbonaceous material is usually 0.005 or more, preferably 0.01 or more, more preferably 0.015 or more, and usually 0.67 or less. When the orientation ratio is below the above range, the high density charge and discharge characteristics may be degraded. The upper limit of the above range is the theoretical upper limit value of the orientation ratio of the carbonaceous material.
The orientation ratio is measured by X-ray diffraction after pressure-molding the sample. A molding obtained by filling 0.47 g of a sample into a molding machine having a diameter of 17 mm and compressing it at 58.8 MN · m−2 is set using clay to be flush with the surface of the sample holder for measurement. Measure X-ray diffraction. From the obtained peak intensities of (110) diffraction and (004) diffraction of carbon, a ratio represented by (110) diffraction peak intensity / (004) diffraction peak intensity is calculated. The orientation ratio calculated by the measurement is defined as the orientation ratio of the carbonaceous material in the present invention.

The X-ray diffraction measurement conditions are as follows. "2θ" indicates a diffraction angle.
Target: Cu (Kα ray) graphite monochromator Slit:
Divergence slit = 0.5 degree Photo acceptance slit = 0.15 mm
Scattering slit = 0.5 degree Measurement range and step angle / measurement time:
(110) plane: 75 degrees ≦ 2θ ≦ 80 degrees 1 degree / 60 seconds (004) plane: 52 degrees ≦ 2θ ≦ 57 degrees 1 degree / 60 seconds

(8) Aspect ratio (powder)
The aspect ratio of the carbonaceous material is usually 1 or more, and usually 10 or less, preferably 8 or less, and more preferably 5 or less. When the aspect ratio exceeds the above range, streaking during electrode plate formation and a uniform coated surface can not be obtained, and the high current density charge / discharge characteristics may be degraded. The lower limit of the above range is the theoretical lower limit of the aspect ratio of the carbonaceous material.

  The measurement of the aspect ratio is performed by magnifying and observing particles of the carbonaceous material with a scanning electron microscope. Carbonaceous material when selecting arbitrary 50 graphite particles fixed to the end face of metal of 50 microns or less in thickness, rotating and tilting the stage on which the sample is fixed for each, and observing it three-dimensionally The longest diameter P of the particles and the shortest diameter Q orthogonal to it are measured, and the average value of P / Q is determined. The aspect ratio (P / Q) determined by the measurement is defined as the aspect ratio of the carbonaceous material in the present invention.

(9) Production of electrode For production of the electrode, any known method can be used unless the effect of the present invention is significantly limited. For example, a binder, a solvent, and, if necessary, a thickener, a conductive material, a filler and the like are added to the negative electrode active material to form a slurry, which is applied to a current collector, dried and pressed. Can.

The thickness of the negative electrode active material layer per one side immediately before the non-aqueous electrolyte solution pouring step of the battery is usually 15 μm or more, preferably 20 μm or more, more preferably 30 μm or more, and usually 150 μm or less And 120 μm or less is preferable, and 100 μm or less is more preferable.
If the thickness of the negative electrode active material exceeds this range, the non-aqueous electrolyte solution hardly penetrates to the vicinity of the current collector interface, and the high current density charge / discharge characteristics may be deteriorated. Also, if the value is below this range, the volume ratio of the current collector to the negative electrode active material may increase, and the capacity of the battery may decrease. Alternatively, the negative electrode active material may be roll-formed to form a sheet electrode, or may be formed into a pellet electrode by compression molding.

(10) Current collector Any known current collector can be used as the current collector for holding the negative electrode active material. Examples of the current collector of the negative electrode include metal materials such as copper, nickel, stainless steel, nickel plated steel and the like, but copper is particularly preferable in terms of ease of processing and cost.
When the current collector is a metal material, examples of the shape of the current collector include metal foil, metal cylinder, metal coil, metal plate, metal thin film, expanded metal, punched metal, foamed metal and the like. Among them, preferably a metal thin film, more preferably a copper foil, more preferably a rolled copper foil by a rolling method and an electrolytic copper foil by an electrolytic method, both of which can be used as a current collector.
When the thickness of the copper foil is thinner than 25 μm, a copper alloy (phosphor bronze, titanium copper, Corson alloy, Cu-Cr-Zr alloy, etc.) having higher strength than pure copper can be used.

  The thickness of the current collector is arbitrary but is usually 1 μm or more, preferably 3 μm or more, more preferably 5 μm or more, and usually 1 mm or less, preferably 100 μm or less, and more preferably 50 μm or less. If the thickness of the metal film is smaller than 1 μm, the strength may be reduced, which may make application difficult. If the thickness is more than 1 mm, the shape of the electrode such as winding may be deformed. The current collector may be in the form of a mesh.

(11) Ratio of Thickness of Current Collector to Negative Electrode Active Material Layer The ratio of thickness of the current collector to negative electrode active material layer is not particularly limited. 150 or less, 20 or less is preferable, 10 or less is more preferable, and usually 0.1 or more, 0.4 or more is preferable, and the value of the material layer thickness) / (the thickness of the current collector) is 1 The above is more preferable.
When the thickness ratio of the current collector to the negative electrode active material layer exceeds the above range, the current collector may generate heat due to Joule heat at the time of high current density charge and discharge. If the above range is exceeded, the volume ratio of the current collector to the negative electrode active material may increase, and the battery capacity may decrease.

(12) Electrode Density The electrode structure when making the negative electrode active material into an electrode is not particularly limited, but the density of the negative electrode active material present on the current collector is preferably 1 g · cm ⁻³ or more, and 1. 2 g · cm ⁻³ or more is more preferable, 1.3 g · cm ⁻³ or more is particularly preferable, and 2.2 g · cm ⁻³ or less is preferable, and 2.1 g · cm ⁻³ or less is more preferable, 2.0 g -Cm ^-3 or less is further preferable, and 1.9 g-cm ^-3 or less is particularly preferable. When the density of the negative electrode active material present on the current collector exceeds the above range, the negative electrode active material particles are destroyed, and the initial irreversible capacity increases, or the non-aqueous system near the current collector / negative electrode active material interface In some cases, the high current density charge / discharge characteristics may be deteriorated due to the decrease in the permeability of the electrolyte solution. If the above range is exceeded, the conductivity between the negative electrode active materials may be reduced, the battery resistance may be increased, and the capacity per unit volume may be reduced.

(13) Binder The binder for binding the negative electrode active material is not particularly limited as long as it is a material stable to the non-aqueous electrolytic solution and the solvent used in the production of the electrode.
Specific examples include resin polymers such as polyethylene, polypropylene, polyethylene terephthalate, polymethyl methacrylate, aromatic polyamide, cellulose, nitrocellulose, etc .; SBR (styrene-butadiene rubber), isoprene rubber, butadiene rubber, fluororubber, NBR ( Rubber-like polymers such as acrylonitrile butadiene rubber), ethylene propylene rubber, etc .; styrene butadiene styrene block copolymer or its hydrogen additive; EPDM (ethylene propylene diene terpolymer), styrene ethylene ethylene terpolymer Thermoplastic elastomeric polymers such as butadiene / styrene copolymers, styrene / isoprene / styrene block copolymers or their hydrogenated products; Syndiotactic-1,2-polybutadiene, polyvinyl acetate, ethylene Soft resin-like polymers such as vinyl acetate copolymer and propylene / α-olefin copolymer; Fluorine compounds such as polyvinylidene fluoride, polytetrafluoroethylene, fluorinated polyvinylidene fluoride, polytetrafluoroethylene / ethylene copolymer and the like Examples thereof include polymers, and polymer compositions having ion conductivity of alkali metal ions (particularly, lithium ions). One of these may be used alone, or two or more of these may be used in any combination and ratio.

The solvent for forming the slurry is not particularly limited as far as it is a solvent capable of dissolving or dispersing the negative electrode active material, the binder, and the thickener and conductive material used as needed. Instead, either an aqueous solvent or an organic solvent may be used.
Examples of the aqueous solvent include water, alcohol and the like, and examples of the organic solvent include N-methyl pyrrolidone (NMP), dimethylformamide, dimethyl acetamide, methyl acetamide, methyl ethyl ketone, cyclohexanone, methyl acetate, methyl acrylate, diethyl triamine, N , N-dimethylaminopropylamine, tetrahydrofuran (THF), toluene, acetone, diethyl ether, dimethylacetamide, hexamethylphosphaamide, dimethylsulfoxide, benzene, xylene, quinoline, pyridine, methylnaphthalene, hexane and the like. .

In particular, when an aqueous solvent is used, it is preferable to use a latex such as SBR to make a slurry by combining a thickener with a dispersing agent and the like. These solvents may be used alone or in any combination of two or more with any proportion.
The ratio of the binder to the negative electrode active material is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, particularly preferably 0.6% by mass or more, and preferably 20% by mass or less, 15% by mass The following are more preferable, 10 mass% or less is further preferable, and 8 mass% or less is particularly preferable. When the ratio of the binder to the negative electrode active material exceeds the above range, the binder ratio in which the amount of binder does not contribute to the battery capacity may increase, which may result in a decrease in the battery capacity. Moreover, if it is less than the said range, strength reduction of a negative electrode may be caused.

In particular, when the main component contains a rubbery polymer represented by SBR, the ratio of the binder to the negative electrode active material is usually 0.1% by mass or more, preferably 0.5% by mass or more, and 0 6 mass% or more is more preferable, and 5 mass% or less is usually, 3 mass% or less is preferable, and 2 mass% or less is more preferable.
When the fluorine-containing polymer represented by polyvinylidene fluoride is contained in the main component, the ratio to the negative electrode active material is usually 1% by mass or more, preferably 2% by mass or more, and 3% by mass or more Moreover, it is 15 mass% or less normally, 10 mass% or less is preferable, and 8 mass% or less is still more preferable.

  Thickeners are usually used to adjust the viscosity of the slurry. The thickener is not particularly limited, and specific examples include carboxymethylcellulose, methylcellulose, hydroxymethylcellulose, ethylcellulose, polyvinyl alcohol, oxidized starch, phosphorylated starch, casein and salts thereof. One of these may be used alone, or two or more of these may be used in any combination and ratio.

  Furthermore, when a thickener is used, the ratio of the thickener to the negative electrode active material is usually 0.1% by mass or more, preferably 0.5% by mass or more, and more preferably 0.6% by mass or more. Moreover, it is 5 mass% or less normally, 3 mass% or less is preferable, and 2 mass% or less is still more preferable. When the ratio of the thickener to the negative electrode active material is below the above range, the coatability may be significantly reduced. If the above range is exceeded, the proportion of the negative electrode active material in the negative electrode active material layer may be reduced, and the battery capacity may be reduced or the resistance between the negative electrode active material may be increased.

2-3-3. Metal Compound-Based Material, and Configuration, Physical Properties, Preparation Method of Negative Electrode Using Metal Compound-Based Material>
As a metal compound based material used as a negative electrode active material, a single metal or alloy which forms a lithium alloy as long as it can occlude and release lithium, or oxides, carbides, nitrides, silicides, sulfides thereof There is no particular limitation on any of the compounds such as phosphide. Examples of such metal compounds include compounds containing metals such as Ag, Al, Ba, Bi, Cu, Ga, Ge, In, Ni, P, Pb, Sb, Si, Sn, Sr, and Zn. Among them, a single metal or alloy forming a lithium alloy is preferable, a material containing a Group 13 or 14 metal / metalloid element (that is, excluding carbon) is more preferable, and silicon (Si) is more preferable. ), Tin (Sn) or lead (Pb) (hereinafter, these three elements may be referred to as “specific metal elements”) single metals or alloys containing these atoms, or metals thereof (specific metal elements) Preferably, single metals, alloys and compounds of silicon, and single metals, alloys and compounds of tin are particularly preferred. One of these may be used alone, or two or more of these may be used in any combination and ratio.

  Examples of the negative electrode active material having at least one atom selected from specific metal elements include single metals of any one specific metal element, alloys composed of two or more specific metal elements, and one or more kinds Alloy consisting of the specific metal element of the above and one or more other metal elements, a compound containing one or more specific metal elements, or an oxide, carbide or nitride of the compound・ Complex compounds such as silicides, sulfides and phosphides can be mentioned. By using these simple metals, alloys or metal compounds as the negative electrode active material, the capacity of the battery can be increased.

  In addition, compounds in which these composite compounds are complexly bonded to several kinds of elements such as simple metals, alloys, or nonmetal elements can also be mentioned as an example. More specifically, for example, in silicon and tin, an alloy of these elements and a metal which does not operate as a negative electrode can be used. For example, in tin, a complex compound containing 5 to 6 elements in combination with a metal other than tin and silicon and acting as a negative electrode, a metal not acting as a negative electrode and a nonmetallic element can also be used. .

  Among these negative electrode active materials, since the capacity per unit mass is large when made into a battery, a metal simple substance of any one specific metal element, an alloy of two or more specific metal elements, oxidation of a specific metal element Materials, carbides, nitrides and the like are preferable, and in particular, silicon and / or tin single metals, alloys, oxides, carbides, nitrides and the like are preferable from the viewpoint of capacity per unit mass and environmental load.

Further, although the capacity per unit mass is inferior to the use of a single metal or an alloy, the following compounds containing silicon and / or tin are also preferable because they are excellent in cycle characteristics.
The element ratio of silicon and / or tin to oxygen is usually 0.5 or more, preferably 0.7 or more, more preferably 0.9 or more, and usually 1.5 or less, preferably 1. 3 or less, more preferably 1.1 or less "oxide of silicon and / or tin".
The element ratio of silicon and / or tin to nitrogen is usually 0.5 or more, preferably 0.7 or more, more preferably 0.9 or more, and usually 1.5 or less, preferably 1. 3 or less, more preferably 1.1 or less "silicon and / or tin nitride".
The element ratio of silicon and / or tin to carbon is usually 0.5 or more, preferably 0.7 or more, more preferably 0.9 or more, and usually 1.5 or less, preferably 1. 3 or less, more preferably 1.1 or less "silicon and / or tin carbide".
Note that any one of the above-described negative electrode active materials may be used alone, or two or more may be used in any combination and ratio.

  The negative electrode in the non-aqueous electrolyte secondary battery of the present invention can be manufactured using any known method. Specifically, as a method of manufacturing a negative electrode, for example, a method in which a negative electrode active material as described above to which a binder, a conductive material, etc. is added is directly roll-formed to form a sheet electrode, or compression molded to form a pellet electrode The negative electrode is usually formed on a current collector for the negative electrode (hereinafter sometimes referred to as “negative electrode current collector”) by a method such as a coating method, a vapor deposition method, a sputtering method, or a plating method. The method of forming the thin film layer (negative electrode active material layer) containing an active material is used. In this case, a binder, a thickener, a conductive material, a solvent, and the like are added to the above-described negative electrode active material to form a slurry, which is applied to the negative electrode current collector, dried and pressed to increase the density. The negative electrode active material layer is formed on the negative electrode current collector.

Examples of the material of the negative electrode current collector include steel, copper alloy, nickel, nickel alloy, stainless steel and the like. Among these, copper foil is preferable in terms of easy processing into a thin film and cost.
The thickness of the negative electrode current collector is usually 1 μm or more, preferably 5 μm or more, and usually 100 μm.
Below, Preferably it is 50 micrometers or less. If the thickness of the negative electrode current collector is too thick, the capacity of the entire battery may be too low. Conversely, if it is too thin, the handling may be difficult.

  In order to improve the binding effect with the negative electrode active material layer formed on the surface, the surface of the negative electrode current collector is preferably roughened in advance. The surface is roughened by blasting, rolling with a rough surface roll, coated abrasive with abrasive particles fixed, grinding machine with a wire brush etc. equipped with a grindstone, emery buff, steel wire etc. Chemical polishing method, electro polishing method, chemical polishing method, and the like.

The slurry for forming the negative electrode active material layer is usually prepared by adding a binder, a thickener and the like to the negative electrode material. In addition, the "negative electrode material" in this specification shall refer to the material which united the negative electrode active material and the electrically conductive material.
The content of the negative electrode active material in the negative electrode material is preferably 70% by mass or more, particularly 75% by mass or more, and usually 97% by mass or less, particularly 95% by mass or less. When the content of the negative electrode active material is too small, the capacity of the secondary battery using the obtained negative electrode tends to be insufficient, and when it is too large, the content of the binder and the like is relatively insufficient. This is because the strength of the negative electrode tends to be insufficient. When two or more negative electrode active materials are used in combination, the total amount of the negative electrode active materials may be set to satisfy the above range.

  Examples of the conductive material used for the negative electrode include metal materials such as copper and nickel; and carbon materials such as graphite and carbon black. One of these may be used alone, or two or more of these may be used in any combination and ratio. In particular, it is preferable to use a carbon material as the conductive material because the carbon material also acts as an active material. The content of the conductive material in the negative electrode material is preferably 3% by mass or more, particularly 5% by mass or more, and usually 30% by mass or less, particularly 25% by mass or less. If the content of the conductive material is too small, the conductivity tends to be insufficient. If the content is too large, the content of the negative electrode active material or the like is relatively short and the battery capacity and the strength tend to decrease. . When two or more conductive materials are used in combination, the total amount of the conductive materials may satisfy the above range.

  As a binder used for a negative electrode, if it is a safe material with respect to the solvent and electrolyte solution used at the time of electrode manufacture, an arbitrary thing can be used. For example, polyvinylidene fluoride, polytetrafluoroethylene, polyethylene, polypropylene, styrene butadiene rubber isoprene rubber, butadiene rubber, ethylene-acrylic acid copolymer, ethylene methacrylic acid copolymer and the like can be mentioned. One of these may be used alone, or two or more of these may be used in any combination and ratio. The content of the binder is preferably 0.5 parts by mass or more, particularly 1 part by mass or more, and usually 10 parts by mass or less, particularly 8 parts by mass or less, based on 100 parts by mass of the negative electrode material. When the content of the binder is too small, the strength of the obtained negative electrode tends to be insufficient. When the content is too large, the content of the negative electrode active material and the like is relatively insufficient, so the battery capacity and the conductivity tend to be insufficient. In order to When two or more binders are used in combination, the total amount of the binders may be within the above range.

  Examples of the thickener used for the negative electrode include carboxymethylcellulose, methylcellulose, hydroxymethylcellulose, ethylcellulose, polyvinyl alcohol, oxidized starch, phosphorylated starch, casein and the like. One of these may be used alone, or two or more of these may be used in any combination and ratio. A thickener may be used as necessary, but when used, the content of the thickener in the negative electrode active material layer is usually in the range of 0.5% by mass to 5% by mass. Is preferred.

The slurry for forming the negative electrode active material layer is prepared by mixing the above-mentioned negative electrode active material with a conductive material, a binder, and a thickener as necessary, and using an aqueous solvent or an organic solvent as a dispersion medium. . Water is usually used as the aqueous solvent, but solvents other than water such as alcohols such as ethanol and cyclic amides such as N-methylpyrrolidone are used in combination at a ratio of about 30% by mass or less with respect to water It can also be done. Also, as the organic solvent, usually, cyclic amides such as N-methyl pyrrolidone, linear amides such as N, N-dimethylformamide, N, N-dimethylacetamide, and aromatic carbonization such as anisole, toluene, xylene and the like Hydrogens, alcohols such as butanol, cyclohexanol and the like, and cyclic amides such as N-methylpyrrolidone, linear amides such as N, N-dimethylformamide, N, N-dimethylacetamide and the like are preferable among them . In addition, these may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.

The viscosity of the slurry is not particularly limited as long as it can be applied onto the current collector. The amount of the solvent used may be changed at the time of preparation of the slurry so that the viscosity can be applied, and the preparation may be carried out as appropriate.
The obtained slurry is applied onto the above-described negative electrode current collector, dried, and pressed to form a negative electrode active material layer. The method of application is not particularly limited, and a method known per se can be used. The drying method is also not particularly limited, and known methods such as natural drying, heat drying and reduced pressure drying can be used.

The electrode structure when making the negative electrode active material into an electrode by the above method is not particularly limited, but the density of the active material present on the current collector is preferably 1 g · cm ⁻³ or more, and 1.2 g · cm ^-3 or more is more preferable, 1.3 g · cm ⁻³ or more is particularly preferable, and 2.2 g · cm ⁻³ or less is preferable, 2.1 g · cm ⁻³ or less is more preferable, and 2.0 g · cm ^{− 3} or less is further preferable, and 1.9 g * cm < ^-3 > or less is especially preferable.
When the density of the active material present on the current collector exceeds the above range, the active material particles are destroyed and the initial irreversible capacity is increased, or the non-aqueous electrolytic solution near the current collector / active material interface is used. In some cases, the high current density charge / discharge characteristics may be deteriorated due to the decrease in permeability. If the above range is exceeded, the conductivity between the active materials may be reduced, the battery resistance may be increased, and the capacity per unit volume may be reduced.

2-3-4. Configuration, Physical Properties, Preparation Method of Negative Electrode Using Carbonaceous Material and Metal Compound Based Material>
The negative electrode active material of the present invention may contain a metal compound material and the above-mentioned carbonaceous material. The negative electrode active material containing the metal compound material and the carbonaceous material in the present invention is a single metal or alloy forming a lithium alloy, or a compound such as an oxide, a carbide, a nitride, a silicide, or a sulfide thereof. Or a mixture in which the carbonaceous material is mixed in the form of mutually independent particles, or a single metal or alloy forming a lithium alloy, or oxides, carbides, nitrides, silicides, sulfides thereof. And the like compounds may be present on the surface or inside of the carbonaceous material. In the present specification, the composite is not particularly limited as long as it includes metal compound materials and carbonaceous materials, but preferably the metal compound materials and carbonaceous materials have physical and / or chemical properties. Integrated by means of More preferably, the solid components are dispersed and present to such an extent that the metal compound-based material and the carbonaceous material are present at least on both the composite surface and the inside of the bulk. The carbonaceous material is in such a form as to be present for integration by means of chemical and / or chemical bonding.

In such a form, particle surface observation with a scanning electron microscope, particles are embedded in a resin to make a thin piece of resin and a particle cross section is cut out, or a coated film composed of particles is produced to a coated film cross section by a cross section polisher After cutting out the particle cross section, observation is possible by an observation method such as observation of particle cross section with a scanning electron microscope.
The content ratio of the metal compound based material used for the negative electrode active material containing the metal compound based material and the carbonaceous material is not particularly limited, but usually 0.1% by mass or more, preferably 1% by mass or more, more preferably 2 % By mass, more preferably 3% by mass, particularly preferably 5% by mass, and usually 99% by mass or less, preferably 50% by mass or less, more preferably 40% by mass or less, still more preferably 30% by mass % Or less, more preferably 25% by mass or less, particularly preferably 15% by mass or less, and most preferably 10% by mass or less. Within this range, it is preferable in that sufficient capacity can be obtained.

About the carbonaceous material used for the negative electrode active material containing a metal compound type material and a carbonaceous material, it is preferable to satisfy | fill the requirements as described in said <2-3-1>. Moreover, about a metal compound type material, it is desirable to satisfy the following.
As a single metal or alloy forming a lithium alloy, any conventionally known one can be used, but from the viewpoint of capacity and cycle life, a single metal forming a lithium alloy is, for example, Fe, Co, Sb, A metal selected from the group consisting of Bi, Pb, Ni, Ag, Si, Sn, Al, Zr, Cr, P, S, V, Mn, Nb, Mo, Cu, Zn, Ge, In, Ti, etc. or a compound thereof Is preferred. Further, as an alloy for forming a lithium alloy, a metal selected from the group consisting of Si, Sn, As, Sb, Al, Zn and W or a compound thereof is preferable.

With single metals or alloys that form lithium alloys, or compounds such as oxides, carbides, nitrides, silicides and sulfides thereof, metal oxides, metal carbides, metal nitrides, metal silicides, metal sulfides Etc. Alternatively, an alloy composed of two or more metals may be used. Among these, Si or Si compounds are preferable in terms of increasing the capacity. In the present specification, Si or Si compounds are generically referred to as Si compounds. Specific examples of the Si compound include SiOx, SiNx, SiCx, SiZxOy (Z is C or N), and the like in the general formula, and SiOx is preferable. The value of x in the above general formula is not particularly limited, but usually 0 ≦ x <2. The above-mentioned general formula SiOx can be obtained using Si (SiO ₂ ) and metal Si (Si) as raw materials. SiOx has a large theoretical capacity as compared with graphite, and further, amorphous Si or nano-sized Si crystal is easy to get in and out alkali ions such as lithium ions, and it is possible to obtain a high capacity.

The value of x in SiO x is not particularly limited, but generally, x is 0 ≦ x <2, preferably 0.2 or more, more preferably 0.4 or more, and still more preferably 0.6 or more. Preferably it is 1.8 or less, more preferably 1.6 or less, further preferably 1.4 or less, and x = 0 is particularly preferred. Within this range, it is possible to reduce the irreversible capacity due to the bond between Li and oxygen as well as having a high capacity.
Incidentally, as a method for confirming that the metal compound material is a metal material capable of being alloyed with lithium, identification of metal particle phase by X-ray diffraction, observation of particle structure by electron microscope and elemental analysis, fluorescence Elemental analysis by X-ray etc. may be mentioned.

The average particle diameter (d50) of the metal compound material used for the negative electrode active material containing the metal compound material and the carbonaceous material is not particularly limited, but from the viewpoint of cycle life, usually 0.01 μm or more, preferably 0 .05 μm or more, more preferably 0.1 μm or more, still more preferably 0.3 μm or more, usually 10 μm or less, preferably 9 μm or less, more preferably 8 μm or less. When the average particle diameter (d50) is in the above range, volumetric expansion associated with charge and discharge is reduced, and good cycle characteristics can be obtained while maintaining charge and discharge capacity.
The average particle diameter (d50) can be determined by a laser diffraction / scattering particle size distribution measuring method or the like.

The specific surface area is not particularly limited according to the BET method of the metal compound material used for the negative electrode active material containing the metal compound material and the carbonaceous material, but is usually 0.5 m ² / g or more, preferably 1 m ² / g or more Also, it is usually 60 m ² / g or less, preferably 40 m ² / g. When the specific surface area of the metal particles that can be alloyed with Li according to the BET method is within the above range, the charge and discharge efficiency and discharge capacity of the battery are high, lithium is rapidly taken in and out in high speed charge and discharge, and rate characteristics are excellent.

The oxygen content of the metal compound based material used for the negative electrode active material containing the metal compound based material and the carbonaceous material is not particularly limited, but is usually 0.01% by mass or more, preferably 0.05% by mass or more, Also, it is usually 8% by mass or less, preferably 5% by mass or less. The oxygen distribution state in the particle may be present near the surface, present inside the particle, or uniformly present in the particle, but it is particularly preferable to be present near the surface. When the content of oxygen in the metal compound material is in the above range, the strong bond between Si and O suppresses the volume expansion associated with charge and discharge, which is preferable because the cycle characteristics are excellent.
Moreover, about negative electrode preparation of the metal compound type material used for the negative electrode active material containing a metal compound type material and a carbonaceous material, the thing as described in the previous term <2-3-1> carbonaceous material can be used.

2-3-5. Lithium-Containing Metal Complex Oxide Material, and Configuration, Physical Properties, Preparation Method of Negative Electrode Using Lithium-Containing Metal Complex Oxide Material>
The lithium-containing metal complex oxide material used as the negative electrode active material is not particularly limited as long as it can occlude and release lithium, but a lithium-containing complex metal oxide material containing titanium is preferable, and lithium and titanium complex oxidation Particularly preferred is a substance (hereinafter abbreviated as "lithium-titanium composite oxide"). That is, it is particularly preferable to use a lithium-titanium composite oxide having a spinel structure by incorporating it into a negative electrode active material for a non-aqueous electrolyte solution secondary battery, since the output resistance is greatly reduced.

In addition, lithium or titanium of the lithium titanium composite oxide is at least selected from the group consisting of other metal elements such as Na, K, Co, Al, Fe, Ti, Mg, Cr, Ga, Cu, Zn and Nb. It is also preferred that one element be substituted.
The metal oxide is a lithium titanium complex oxide represented by the general formula (3), and in the general formula (3), 0.7 ≦ x ≦ 1.5, 1.5 ≦ y ≦ 2.3, It is preferable that 0 ≦ z ≦ 1.6, because the structure at the time of lithium ion doping / dedoping is stable.

LixTiyMzO ₄ (3)
[In general formula (3), M represents at least one element selected from the group consisting of Na, K, Co, Al, Fe, Ti, Mg, Cr, Ga, Cu, Zn and Nb. ]
Among the compositions represented by the above general formula (3),
(A) 1.2 ≦ x ≦ 1.4, 1.5 ≦ y ≦ 1.7, z = 0
(B) 0.9 ≦ x ≦ 1.1, 1.9 ≦ y ≦ 2.1, z = 0
(C) 0.7 ≦ x ≦ 0.9, 2.1 ≦ y ≦ 2.3, z = 0
Is particularly preferable because the battery performance is well balanced.

Particularly preferable representative compositions of the above compounds are Li _4/3 Ti _5/3 O ₄ in (a), Li ₁ Ti ₂ O ₄ in (b), and Li _4/5 Ti _11/5 O in (c). ₄ In addition, for the structure of Z ≠ 0, for example, Li _4/3 Ti _4/3 Al _1/3 O ₄ is mentioned as a preferable one.
The lithium-titanium composite oxide as a negative electrode active material in the present invention satisfies at least one of characteristics such as physical properties and shape shown in the following (1) to (13) in addition to the above-mentioned requirements. It is particularly preferable to satisfy two or more simultaneously.

(1) BET Specific Surface Area The BET specific surface area of the lithium titanium composite oxide used as the negative electrode active material is preferably 0.5 m ² · g ⁻¹ or more of the specific surface area measured using the BET method, and 0. 7 m ² · g
More preferably at least ^-1, more preferably 1.0 m ² · ^{g -1} or more, particularly preferably 1.5 m ² · ^{g -1} or more,, 200 meters ² · ^{g -1} or less is preferable, 100 m ² · g ^{- 1} or less is more preferable, 50 m < ² > * g <^-1> or less is further more preferable, 25 m < ² > * g <^-1> or less is especially preferable.

  If the BET specific surface area falls below the above range, the reaction area in contact with the non-aqueous electrolyte solution when used as a negative electrode material may decrease, and the output resistance may increase. On the other hand, beyond the above range, the surface and end face portions of the titanium oxide-containing metal oxide crystal increase, and this also causes distortion of the crystal, making irreversible capacity non-negligible, which is preferable. It may be difficult to obtain a battery.

  Measurement of the specific surface area by the BET method is carried out by using a surface area meter (total surface area measurement device manufactured by Okura Riken) and predrying the sample under flowing nitrogen at 350 ° C. for 15 minutes and then using nitrogen of atmospheric pressure. It is carried out by the nitrogen adsorption BET one-point method according to the gas flow method, using a nitrogen-helium mixed gas which is accurately adjusted so that the value of the relative pressure is 0.3. The specific surface area determined by the measurement is defined as the BET specific surface area of the lithium titanium composite oxide in the present invention.

(2) Volume-Based Average Particle Size The volume-based average particle size of lithium titanium composite oxide (secondary particle size when primary particles are aggregated to form secondary particles) is determined by laser diffraction / scattering method. It is defined by the volume-based average particle diameter (median diameter) determined.
The volume-based average particle diameter of the lithium titanium composite oxide is usually 0.1 μm or more, preferably 0.5 μm or more, more preferably 0.7 μm or more, and usually 50 μm or less, preferably 40 μm or less, 30 μm The following is more preferable, and 25 μm or less is particularly preferable.

To measure the volume-based average particle size, a carbon powder is dispersed in a 0.2% by mass aqueous solution (10 mL) of polyoxyethylene (20) sorbitan monolaurate which is a surfactant, and a laser diffraction / scattering type particle size distribution analyzer (LA-700 manufactured by Horiba, Ltd.) is used. The median diameter determined by the measurement is defined as the volume-based average particle diameter of the carbonaceous material in the present invention.
When the volume average particle diameter of the lithium titanium composite oxide is below the above range, a large amount of binder is required at the time of electrode production, and as a result, the battery capacity may be reduced. Moreover, when it exceeds the said range, it will be easy to become an uneven coating surface at the time of electrode plate-making, and it may be undesirable on the battery manufacture process.

(3) Average Primary Particle Size In the case where the primary particles are aggregated to form secondary particles, the average primary particle size of the lithium titanium composite oxide is usually 0.01 μm or more, and 0.05 μm or more. Preferably, 0.1 μm or more is more preferable, 0.2 μm or more is particularly preferable, and usually, 2 μm or less is preferable, 1.6 μm or less is preferable, 1.3 μm or less is more preferable, and 1 μm or less is particularly preferable. When the volume-based average primary particle size exceeds the above range, it is difficult to form spherical secondary particles, which adversely affects the powder packing property or significantly reduces the specific surface area. Performance may be reduced. Moreover, if it is less than the said range, since the reversibility of charging / discharging is inferior in general because a crystal | crystallization becomes undeveloped, the performance of a secondary battery may be reduced.

  The primary particle diameter is measured by observation using a scanning electron microscope (SEM). Specifically, for a photograph at which the particle can be confirmed, for example, a magnification of 10000 to 100000 times, the longest value of the intercept by the left and right boundary lines of the primary particle with respect to the horizontal straight line, for any 50 primary particles It is obtained by finding and taking an average value.

(4) Shape The shape of the particles of lithium titanium composite oxide may be a block, polyhedron, sphere, oval sphere, plate, needle or column as conventionally used, among which primary particles are aggregated. Preferably, secondary particles are formed, and the shape of the secondary particles is spherical or elliptical.
Usually, since the active material in the electrode expands and contracts with the charge and discharge of the electrochemical element, the active material is likely to be broken due to the stress, or deterioration such as breakage of the conductive path may occur. Therefore, the primary particles are aggregated to form secondary particles rather than being single-particle active materials of only primary particles, so that the stress of expansion and contraction is alleviated and deterioration is prevented.
In addition, since spherical or elliptical spherical particles have less orientation at the time of molding of the electrode than particles having plate-like equiaxial orientation, expansion and contraction of the electrode at the time of charge and discharge are less, and the electrode is prepared Also in the mixing with the conductive material at the time of mixing, it is preferable because it is easily mixed uniformly.

(5) Tap Density Tap density lithium-titanium composite oxide is preferably from 0.05 g · ^{cm -3} or more, 0.1 g · ^{cm -3} or more, and more preferably 0.2 g · ^{cm -3} or more, 0.4 g · cm ⁻³ or more is particularly preferable, 2.8 g · cm ⁻³ or less is preferable, 2.4 g · cm ⁻³ or less is more preferable, and 2 g · cm ⁻³ or less is particularly preferable. When the tap density is lower than the above range, the packing density is difficult to increase when used as a negative electrode, and the contact area between particles decreases, so the resistance between particles may increase and the output resistance may increase. Moreover, when the said range is exceeded, the space | gap between particle | grains in an electrode may decrease too much, and the flow path of non-aqueous electrolyte solution may decrease, and output resistance may increase.

The tap density is measured by passing the sample through a 300 μm mesh screen and dropping the sample into a 20 cm ³ tapping cell to fill the sample to the top end face of the cell, and then using a powder density measuring instrument (eg, Seishin Enterprise Co., Ltd.) Tapping with a stroke length of 10 mm is performed 1000 times using a tap denser, and the density is calculated from the volume at that time and the mass of the sample. The tap density calculated by the measurement is defined as the tap density of the lithium titanium composite oxide in the present invention.

(6) Circularity When the circularity is measured as the degree of spherical shape of the lithium titanium composite oxide, it is preferable to fall within the following range. Circularity is defined as "circularity = (peripheral length of equivalent circle having the same area as particle projection shape) / (actual peripheral length of particle projection shape)", and the theoretical spherical shape when the circularity is 1 It becomes.

  The circularity of the lithium titanium composite oxide is preferably as close to 1 as possible, is usually 0.10 or more, preferably 0.80 or more, more preferably 0.85 or more, and particularly preferably 0.90 or more. The high current density charge / discharge characteristics improve as the degree of circularity increases. Therefore, when the circularity is less than the above range, the filling property of the negative electrode active material may be reduced, the resistance between particles may be increased, and the high current density charge / discharge characteristics may be deteriorated for a short time.

  The measurement of the degree of circularity is performed using a flow type particle image analyzer (FPIA manufactured by Sysmex Corporation). About 0.2 g of a sample is dispersed in a 0.2 mass% aqueous solution (about 50 mL) of polyoxyethylene (20) sorbitan monolaurate which is a surfactant, and irradiated with ultrasonic waves of 28 kHz for 1 minute at a power of 60 W The detection range is specified to 0.6 to 400 μm, and measurement is performed on particles having a particle size in the range of 3 to 40 μm. The degree of circularity determined by the measurement is defined as the degree of circularity of the lithium titanium composite oxide in the present invention.

(7) Aspect Ratio The aspect ratio of the lithium titanium composite oxide is usually 1 or more, and usually 5 or less, preferably 4 or less, more preferably 3 or less, and particularly preferably 2 or less. If the aspect ratio exceeds the above range, streaking during electrode plate formation and a uniform coated surface can not be obtained, and the high current density charge / discharge characteristics may be deteriorated for a short time. The lower limit of the above range is the theoretical lower limit of the aspect ratio of the lithium titanium composite oxide.

  The measurement of the aspect ratio is performed by magnifying and observing particles of the lithium-titanium composite oxide with a scanning electron microscope. Select any 50 particles fixed to the end face of metal with a thickness of 50 μm or less, rotate the stage on which the sample is fixed for each of them, tilt, and become the longest of the particles when observed three-dimensionally The diameter P 'and the shortest diameter Q' orthogonal to it are measured, and the average value of P '/ Q' is determined. The aspect ratio (P '/ Q') determined by the measurement is defined as the aspect ratio of the lithium titanium composite oxide in the present invention.

(8) Method of Producing Negative Electrode Active Material The method of producing a lithium titanium composite oxide is not particularly limited as long as the scope of the present invention is not exceeded, but several methods can be mentioned. Methods are used.
For example, a method of uniformly mixing titanium source materials such as titanium oxide, source materials of other elements if necessary, and Li sources such as LiOH, Li ₂ CO ₃ , LiNO ₃ and firing at high temperature to obtain an active material Can be mentioned.

In particular, various methods can be considered to produce a spherical or elliptical spherical active material. As an example, titanium starting materials such as titanium oxide and, if necessary, starting materials of other elements are dissolved or pulverized and dispersed in a solvent such as water, and the pH is adjusted while stirring to prepare a spherical precursor It is recovered, dried if necessary, added with a Li source such as LiOH, Li ₂ CO ₃ or LiNO ₃ and calcined at high temperature to obtain an active material.

Further, as another example, a titanium raw material such as titanium oxide and, if necessary, raw materials of other elements are dissolved or pulverized and dispersed in a solvent such as water, and dried and formed by a spray dryer or the like to form a sphere Or a spheroid precursor, to which a Li source such as LiOH, Li ₂ CO ₃ , LiNO ₃ or the like is added, followed by calcination at high temperature to obtain an active material.
Further, as another method, a titanium source material such as titanium oxide, a Li source such as LiOH, Li ₂ CO ₃ , LiNO ₃ and, if necessary, source materials of other elements are dissolved or pulverized in a solvent such as water It is dispersed and dried and formed by a spray drier or the like to form a spherical or elliptical spherical precursor, which is calcined at high temperature to obtain an active material.

  In addition, during these steps, elements other than Ti, for example, Al, Mn, Ti, V, Cr, Mn, Fe, Co, Li, Ni, Cu, Zn, Mg, Ga, Zr, C, Si, Sn It is also possible that Ag is present in the titanium-containing metal oxide structure and / or in contact with the titanium-containing oxide. By containing these elements, it becomes possible to control the operating voltage and capacity of the battery.

(9) Production of Electrode For production of the electrode, any known method can be used. For example, a binder, a solvent, and, if necessary, a thickener, a conductive material, a filler and the like are added to the negative electrode active material to form a slurry, which is applied to a current collector, dried and pressed. Can.
The thickness of the negative electrode active material layer per one side immediately before the non-aqueous electrolyte solution pouring step of the battery is usually 15 μm or more, preferably 20 μm or more, more preferably 30 μm or more, and the upper limit is 150 μm or less, preferably 120 μm The following, more preferably 100 μm or less is desirable.
If this range is exceeded, it is difficult for the non-aqueous electrolytic solution to penetrate to the vicinity of the current collector interface, and the high current density charge / discharge characteristics may be degraded. In addition, if it is below this range, the volume ratio of the current collector to the negative electrode active material may increase, and the capacity of the battery may decrease. Alternatively, the negative electrode active material may be roll-formed to form a sheet electrode, or may be formed into a pellet electrode by compression molding.

(10) Current collector Any known current collector can be used as the current collector for holding the negative electrode active material. As the current collector of the negative electrode, metal materials such as copper, nickel, stainless steel, nickel plated steel and the like can be mentioned. Among them, copper is particularly preferable in view of easiness of processing and cost.
When the current collector is a metal material, examples of the shape of the current collector include a metal foil, a metal cylinder, a metal coil, a metal plate, a metal plate, a metal thin film, an expanded metal, a punched metal, a foam metal and the like. Among them, metal foil films containing copper (Cu) and / or aluminum (Al) are preferable, copper foils and aluminum foils are more preferable, and rolled copper foils by rolling method and electrolytic copper by electrolytic method are more preferable. There is a foil, both of which can be used as current collectors.

When the thickness of the copper foil is thinner than 25 μm, a copper alloy (phosphor bronze, titanium copper, Corson alloy, Cu-Cr-Zr alloy, etc.) having higher strength than pure copper can be used. In addition, since the aluminum foil has a low specific gravity, it can reduce the mass of the battery when it is used as a current collector, and can be preferably used.
The current collector made of copper foil manufactured by the rolling method is hard to be broken even if the negative electrode is tightly rounded or rounded at an acute angle because the copper crystals are aligned in the rolling direction, and it is suitably used for small cylindrical batteries be able to.

  In the electrolytic copper foil, for example, a metal drum is immersed in a non-aqueous electrolytic solution in which copper ions are dissolved, and current is supplied while rotating this to deposit copper on the surface of the drum and peel it off It is obtained by Copper may be deposited on the surface of the above-mentioned rolled copper foil by an electrolytic method. Roughening treatment or surface treatment (for example, chromate treatment with a thickness of several nm to about 1 μm, base treatment with Ti or the like, etc.) may be performed on one side or both sides of the copper foil.

The thickness of the current collector is arbitrary but is usually 1 μm or more, preferably 3 μm or more, more preferably 5 μm or more, and usually 1 mm or less, preferably 100 μm or less, and more preferably 50 μm or less.
When the thickness of the current collector is in the above range, the strength is improved and coating becomes easy, and the shape of the electrode is stabilized, which is preferable.

(11) Ratio of Thickness of Current Collector to Active Material Layer The ratio of thickness of the current collector to the active material layer is not particularly limited. The value of “thickness) / (thickness of current collector)” is usually 150 or less, preferably 20 or less, more preferably 10 or less, and usually 0.1 or more, preferably 0.4 or more. , 1 or more is more preferable.
When the thickness ratio of the current collector to the negative electrode active material layer exceeds the above range, the current collector may generate heat due to Joule heat at the time of high current density charge and discharge. If the above range is exceeded, the volume ratio of the current collector to the negative electrode active material may increase, and the battery capacity may decrease.

(12) Electrode Density The electrode structure of the negative electrode active material is not particularly limited, but the density of the active material present on the current collector is preferably 1 g · cm ⁻³ or more, and 1.2 g · ^{cm -3} or more, and more preferably 1.3 g · ^{cm -3} or more, particularly preferably 1.5 g · ^{cm -3} or more, preferably 3 g · ^{cm -3} or less, 2.5 g · cm ^{- 3} or less is more preferable, 2.2 g · cm ⁻³ or less is more preferable, and 2 g · cm ⁻³ or less is particularly preferable.
When the density of the active material present on the current collector exceeds the above range, the binding between the current collector and the negative electrode active material may be weak, and the electrode and the active material may be separated. If the above range is exceeded, the conductivity between the negative electrode active materials may be reduced, and the battery resistance may be increased.

(13) Binder The binder for binding the negative electrode active material is not particularly limited as long as it is a material stable to the non-aqueous electrolytic solution and the solvent used in the production of the electrode.
Specific examples include resin polymers such as polyethylene, polypropylene, polyethylene terephthalate, polymethyl methacrylate, polyimide, aromatic polyamide, cellulose, nitrocellulose, etc .; SBR (styrene-butadiene rubber), isoprene rubber, butadiene rubber, fluororubber, Rubber-like polymers such as NBR (acrylonitrile butadiene rubber), ethylene propylene rubber, etc .; styrene butadiene styrene block copolymer and its hydrogenated product; EPDM (ethylene propylene diene terpolymer), styrene ス チ レ ンThermoplastic elastomeric polymers such as ethylene butadiene styrene copolymer, styrene isoprene styrene block copolymer and hydrogenated products thereof; syndiotactic 1,2-polybutadiene polyvinyl acetate Soft resin-like polymers such as ethylene / vinyl acetate copolymer, propylene / α-olefin copolymer; polyvinylidene fluoride, polytetrafluoroethylene, fluorinated polyvinylidene fluoride, polytetrafluoroethylene / ethylene copolymer, etc. Fluorinated polymers; polymer compositions having ion conductivity of alkali metal ions (particularly lithium ions), and the like. One of these may be used alone, or two or more of these may be used in any combination and ratio.

The solvent for forming the slurry is not particularly limited as long as it is a solvent capable of dissolving or dispersing the negative electrode active material, the binder, the thickener used as needed, and the conductive material. Instead, either an aqueous solvent or an organic solvent may be used.
Examples of the aqueous solvent include water, alcohol and the like, and examples of the organic solvent include N-methyl pyrrolidone (NMP), dimethylformamide, dimethyl acetamide, methyl acetamide, methyl ethyl ketone, cyclohexanone, methyl acetate, methyl acrylate, diethyl triamine, N , N-dimethylaminopropylamine, tetrahydrofuran (THF), toluene, acetone, dimethyl ether, dimethyl acetamide, hexameryl phosphamide, dimethyl sulfoxide, benzene, xylene, quinoline, pyridine, methyl naphthalene, hexane and the like. In particular, in the case of using an aqueous solvent, a dispersant or the like is added to the above-mentioned thickener together with the above-mentioned thickener, and a slurry such as SBR is used. In addition, these may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.

The ratio of the binder to the negative electrode active material is usually 0.1% by mass or more, preferably 0.5% by mass or more, more preferably 0.6% by mass or more, and usually 20% by mass or less, and 15% by mass. % Or less is preferable, 10% by mass or less is more preferable, and 8% by mass or less is particularly preferable.
When the ratio of the binder to the negative electrode active material is in the above range, the binder ratio at which the binder amount does not contribute to the battery capacity decreases, the battery capacity increases, and the strength of the negative electrode is maintained, which is preferable in the battery manufacturing process.

  In particular, when the main component contains a rubbery polymer represented by SBR, the ratio of the binder to the active material is usually 0.1% by mass or more, preferably 0.5% by mass or more, and 0. 6% by mass or more is more preferable, and usually 5% by mass or less, 3% by mass or less is preferable, and 2% by mass or less is more preferable.

  When a fluorine-based polymer represented by polyvinylidene fluoride is contained in the main component, the ratio to the active material is usually 1% by mass or more, preferably 2% by mass or more, and more preferably 3% by mass or more. It is usually 15% by mass or less, preferably 10% by mass or less, and more preferably 8% by mass or less.

  Thickeners are usually used to adjust the viscosity of the slurry. The thickener is not particularly limited, and specific examples include carboxymethylcellulose, methylcellulose, hydroxymethylcellulose, ethylcellulose, polyvinyl alcohol, oxidized starch, phosphorylated starch, casein and salts thereof. One of these may be used alone, or two or more of these may be used in any combination and ratio.

  Furthermore, when a thickener is used, the ratio of the thickener to the negative electrode active material is 0.1% by mass or more, preferably 0.5% by mass or more, and more preferably 0.6% by mass or more. It is usually 5% by mass or less, preferably 3% by mass or less, and more preferably 2% by mass or less. When the ratio of the thickener to the negative electrode active material is within the above range, it is preferable from the point of application of the pressure-sensitive adhesive, and the ratio of the active material in the negative electrode active material layer is preferable. Preferred in view of the resistance between the active substances.

<2-4 positive electrode>
The positive electrode has a positive electrode active material layer on a current collector, and the positive electrode active material will be described below.

<2-4-1 Positive electrode active material>
The positive electrode active material used for a positive electrode is demonstrated below.

(1) Composition The positive electrode active material is not particularly limited as long as it can electrochemically store and release lithium ions, and for example, a material containing lithium and at least one transition metal is preferable. Specific examples thereof include lithium transition metal composite oxides and lithium-containing transition metal phosphate compounds.

The transition metal of the lithium transition metal complex oxide is preferably V, Ti, Cr, Mn, Fe, Co, Ni, Cu or the like, and as a specific example, lithium cobalt complex oxide such as LiCoO ₂ , LiMnO ₂ , LiMn Examples include lithium-manganese composite oxides such as ₂ O ₄ and Li ₂ MnO ₄ , lithium-nickel composite oxides such as LiNiO ₂ , and the like. In addition, a part of transition metal atoms, which are main components of these lithium transition metal complex oxides, are Al, Ti, V, Cr, Mn, Fe, Co, Li, Ni, Cu, Zn, Mg, Ga, Zr, Si And the like, and the like, and examples thereof include lithium-cobalt-nickel composite oxide, lithium-cobalt-manganese composite oxide, lithium-nickel-manganese composite oxide, lithium-nickel, etc. Cobalt-manganese composite oxides and the like can be mentioned.

Specific examples of those substituted, for _{example, Li 1 + a Ni 0.5 Mn} 0.5 O 2, Li 1 + a Ni 0.8 Co 0.2 O 2, Li 1 + a Ni 0.85 Co 0.10 Al 0. _{05 O 2, Li 1 + a} Ni 0.33 Co 0.33 Mn 0.33 O 2, Li 1 + a Ni 0.45 Co 0.45 Mn 0.1 O 2, Li 1 + a Mn 1.8 Al 0.2 O 4 Li _{1 + a} Mn _1.5 Ni _0.5 O ₄ , x Li ₂ MnO _3. (1-x) Li _{1 + a} MO ₂ (M = transition metal), and the like (a = 0 <a ≦ 3.0).

The lithium-containing transition metal phosphate compound is LixMPO ₄ (M is a kind of element selected from the group consisting of transition metals of Groups 4 to 11 of Period 4 of the periodic table, x is 0 <x <1.2) Can be represented as a basic composition, and the transition metal (M) is selected from the group consisting of V, Ti, Cr, Mg, Zn, Ca, Cd, Sr, Ba, Co, Ni, Fe, Mn and Cu. Preferably, it is at least one element, and more preferably at least one element selected from the group consisting of Co, Ni, Fe, and Mn. For example, iron phosphates such as LiFePO ₄ , Li ₃ Fe ₂ (PO ₄ ) ₃ and LiFeP ₂ O ₇ , cobalt phosphates such as LiCoPO ₄ , Li
Manganese phosphate such as MnPO _4, nickel phosphate such as LiNiPO _4, part of the transition metal atom comprised mainly of these lithium transition metal phosphate compound Al, Ti, V, Cr, Mn, Fe, Co And those substituted with other metals such as Li, Ni, Cu, Zn, Mg, Ga, Zr, Nb and Si.

The above-mentioned “LixMPO ₄ ” includes not only the composition represented by the composition formula but also one in which a part of the transition metal (M) site in the crystal structure is substituted with another element means. Furthermore, it is meant to include not only stoichiometric compositions but also non-stoichiometric compositions in which some elements are deficient or the like. When the other element substitution is performed, it is usually 0.1 mol%, preferably 0.2 mol% or more. Also, it is usually 5 mol% or less, preferably 2.5 mol% or less.
The positive electrode active materials may be used alone or in combination of two or more.

(2) Surface Coating A surface of the above-mentioned positive electrode active material may be used with a substance having a composition different from the material constituting the main positive electrode active material (hereinafter referred to as “surface adhesion substance” as appropriate) attached. . Examples of surface adhesion substances include aluminum oxide, silicon oxide, titanium oxide, zirconium oxide, magnesium oxide, calcium oxide, boron oxide, antimony oxide, oxides such as bismuth oxide, lithium sulfate, sodium sulfate, potassium sulfate, magnesium sulfate, Examples thereof include sulfates such as calcium sulfate and aluminum sulfate, and carbonates such as lithium carbonate, calcium carbonate and magnesium carbonate.

These surface adhesion substances are, for example, dissolved or suspended in a solvent and impregnated and added to the positive electrode active material and then dried, or the surface adhesion substance precursor is dissolved or suspended in a solvent and impregnated and added to the positive electrode active material. After that, it can be made to adhere to the surface of the positive electrode active material by a method of reacting by heating etc., a method of adding it to the positive electrode active material precursor and simultaneously baking it.
The mass of the surface adhesion substance adhering to the surface of the positive electrode active material is usually 0.1 ppm or more, preferably 1 ppm or more, more preferably 10 ppm or more, and usually 20%, based on the mass of the positive electrode active material. Or less, 10% or less is preferable, and 5% or less is more preferable.

  The surface adhesion substance can suppress the oxidation reaction of the non-aqueous electrolytic solution on the surface of the positive electrode active material, and can improve the battery life. However, if the adhesion amount is below the above range, the effect is not sufficiently exhibited, and if it is above the above range, the resistance may increase to inhibit the lithium ions from entering and exiting, so the above range is preferable.

(3) Shape The shape of the positive electrode active material particles may be massive, polyhedral, spherical, elliptical, plate-like, needle-like, columnar, etc. as conventionally used. It is preferable that the secondary particles be in the form of secondary particles, and the shape of the secondary particles is spherical or elliptical.
Usually, since the active material in the electrode expands and contracts with the charge and discharge of the electrochemical element, the active material is likely to be broken due to the stress, or deterioration such as breakage of the conductive path may occur. Therefore, the primary particles are aggregated to form secondary particles rather than a single particle active material consisting only of primary particles, thereby alleviating the stress of expansion and contraction and preventing deterioration.
In addition, since spherical or elliptical spherical particles have less orientation at the time of molding of the electrode than plate-like equiaxially oriented particles, expansion and contraction of the electrode at the time of charge and discharge are also small, and when forming the electrode Also in the mixing with the conductive material of the above, it is preferable because it is easily mixed uniformly.

(4) Tap Density The tap density of the positive electrode active material is usually 0.4 g · cm ⁻³ or more, preferably 0.6 g · cm ⁻³ or more, and more preferably 0.8 g · cm ⁻³ or more. 0 g · ^{cm -3} or more are particularly preferred, and generally not more than ^{4.0g · cm -3, 3.8g · cm} -3 or less.
By using a metal composite oxide powder with a high tap density, a high density positive electrode active material layer can be formed. Therefore, when the tap density of the positive electrode active material is less than the above range, the amount of dispersion medium required at the time of forming the positive electrode active material layer increases, and the required amount of the conductive material and the binder increases, The filling rate of the positive electrode active material may be restricted, and the battery capacity may be restricted. Generally, the tap density is preferably as high as possible and there is no upper limit, but if it is less than the above range, diffusion of lithium ions in the positive electrode active material layer with the non-aqueous electrolyte medium is limited and load characteristics tend to deteriorate. There is a case.

The tap density is measured by passing the sample through a 300 μm mesh screen and dropping the sample into a 20 cm ³ tapping cell to fill the cell volume, and then using a powder density measuring instrument (eg, Tap Denser manufactured by Seishin Co., Ltd.) Tapping is performed 1000 times using a stroke length of 10 mm, and the density is calculated from the volume at that time and the mass of the sample. The tap density calculated by the measurement is defined as the tap density of the positive electrode active material in the present invention.

(5) Median diameter d50
The median diameter d50 of the particles of the positive electrode active material (secondary particle diameter when primary particles are aggregated to form secondary particles) should be measured using a laser diffraction / scattering particle size distribution analyzer. Can.
The median diameter d50 is usually 0.1 μm or more, preferably 0.5 μm or more, more preferably 1 μm or more, particularly preferably 3 μm or more, and usually 20 μm or less, preferably 18 μm or less, more preferably 16 μm or less And 15 μm or less are particularly preferable. If the median diameter d50 is less than the above range, high bulk density products may not be obtained. If the above range is exceeded, it takes time to diffuse lithium in the particles, resulting in deterioration of the battery characteristics or formation of the battery positive electrode. That is, when the active material and the conductive material, the binder, and the like are slurried with a solvent and applied in a thin film, streaks may be drawn.

In addition, the packing property at the time of positive electrode preparation can also be further improved by mixing two or more types and the positive electrode active material with different median diameters d50 by an arbitrary ratio.
The median diameter d50 is measured using a 0.1 mass% sodium hexametaphosphate aqueous solution as a dispersion medium and using a Horiba LA-920 particle size distribution meter as a particle size distribution, and after a 5-minute ultrasonic dispersion, it has a refractive index of 1.24. Set and measure.

(6) Average Primary Particle Size When primary particles are aggregated to form secondary particles, the average primary particle size of the positive electrode active material is usually 0.03 μm or more, preferably 0.05 μm or more, 0. 08 μm or more is more preferable, 0.1 μm or more is particularly preferable, and usually 5 μm or less, 4 μm or less is preferable, 3 μm or less is more preferable, and 2 μm or less is particularly preferable. If the above range is exceeded, it is difficult to form spherical secondary particles, which adversely affects the powder packing property or significantly reduces the specific surface area, and thus the possibility of deterioration of battery performance such as output characteristics may increase. is there. Moreover, if it is less than the said range, since the reversibility of charging / discharging is inferior normally because a crystal | crystallization is undeveloped, the performance of a secondary battery may be reduced.

  The average primary particle size is measured by observation using a scanning electron microscope (SEM). Specifically, in a photograph at a magnification of 10000, the longest value of the intercept by the left and right boundary lines of the primary particle with respect to the straight line in the horizontal direction is obtained for any 50 primary particles, and the average value is obtained Be

(7) BET Specific Surface Area The BET specific surface area of the positive electrode active material is usually 0.1 m ² · g ⁻¹ or more, 0.2 m ² · g ⁻¹ or more as the specific surface area measured using the BET method. Is more preferably 0.3 m ² · g ^-1 or more, and usually 50 m ² · g ^-1 or less, 40 m ² · g ^-1 or less is preferable, and 30 m ² · g ^-1 or less is more preferable. When the value of the BET specific surface area falls below the above range, the battery performance tends to be deteriorated. Moreover, when it exceeds the said range, a tap density becomes difficult to go up and the coating property at the time of positive electrode active material formation may fall.

  The BET specific surface area is measured using a surface area meter (Okura Riken fully automatic surface area measuring device). The sample was predried at 150 ° C. for 30 minutes under nitrogen flow, and then the gas was used with a nitrogen-helium mixed gas that was accurately adjusted so that the value of nitrogen relative to atmospheric pressure was 0.3. It measures by the nitrogen adsorption BET one-point method by a flow method. The specific surface area determined by the measurement is defined as the BET specific surface area of the anode active material in the present invention.

(8) Production Method of Positive Electrode Active Material The production method of the positive electrode active material is not particularly limited as long as the scope of the present invention is not exceeded, but several methods can be mentioned, and a general production method of inorganic compounds The method is used.
In particular, various methods can be considered to produce spherical or elliptical spherical active materials, but one of them is, for example, transition metal raw materials such as transition metal nitrates and sulfates, and raw materials of other elements as necessary. Is dissolved or pulverized and dispersed in a solvent such as water, and the pH is adjusted while stirring to prepare a spherical precursor, which is dried if necessary, then LiOH, Li ₂ CO ₃ , LiNO There is a method of adding an Li source such as ₃ and firing at high temperature to obtain an active material.

In addition, as an example of another method, transition metal source materials such as transition metal nitrates, sulfates, hydroxides, oxides and so forth and, if necessary, source materials of other elements are dissolved or pulverized and dispersed in a solvent such as water. And dry-form it with a spray drier etc. to form a spherical or elliptical spherical precursor, to which Li source such as LiOH, Li ₂ CO ₃ , LiNO ₃ etc. is added and calcined at high temperature to obtain an active material Can be mentioned.

Further, as another example of the method, transition metal source materials such as transition metal nitrate, sulfate, hydroxide, oxide and the like, Li source such as LiOH, Li ₂ CO ₃ , LiNO ₃ and other elements as necessary The raw material is dissolved or pulverized and dispersed in a solvent such as water, and it is dried and formed by a spray drier or the like to form a spherical or ellipsoidal precursor, which is calcined at high temperature to obtain an active material. It can be mentioned.

<2-4-2 electrode structure and manufacturing method>
Hereinafter, the configuration of the positive electrode used in the present invention and the method for producing the same will be described.

(1) Production Method of Positive Electrode The positive electrode is produced by forming a positive electrode active material layer containing positive electrode active material particles and a binder on a current collector. Production of the positive electrode using the positive electrode active material can be produced by any known method. That is, a positive electrode active material, a binder, and optionally a conductive material, a thickener and the like are mixed in a dry state to form a sheet, which is pressure bonded to the positive electrode current collector, or a liquid medium of these materials A positive electrode can be obtained by forming a positive electrode active material layer on a current collector by applying it as a slurry by dissolving or dispersing it as a slurry and drying it.

The content of the positive electrode active material in the positive electrode active material layer is preferably 80% by mass or more, more preferably 82% by mass or more, and particularly preferably 84% by mass or more. The upper limit is preferably 99% by mass or less, more preferably 98% by mass or less. If the content of the positive electrode active material in the positive electrode active material layer is low, the electrical capacity may be insufficient. Conversely, if the content is too high, the strength of the positive electrode may be insufficient. The positive electrode active material powder in the present invention may be used alone, or two or more of different compositions or different powder physical properties may be used in any combination and ratio.

(2) Conductive material As a conductive material, a well-known conductive material can be used arbitrarily. Specific examples thereof include metal materials such as copper and nickel; graphite (graphite) such as natural graphite and artificial graphite; carbon blacks such as acetylene black; and carbonaceous materials such as amorphous carbon such as needle coke. In addition, these may be used individually by 1 type and may use 2 or more types together by arbitrary combinations and a ratio.

  The conductive material is usually 0.01% by mass or more, preferably 0.1% by mass or more, more preferably 1% by mass or more, and usually 50% by mass or less, preferably 30% by mass or less in the positive electrode active material layer. More preferably, it is used so that 15 mass% or less is contained. If the content is lower than the above range, the conductivity may be insufficient. Also, if it exceeds the above range, the battery capacity may be reduced.

(3) Binder The binder used in the production of the positive electrode active material layer is not particularly limited as long as it is a material stable to the non-aqueous electrolytic solution and the solvent used in the production of the electrode.
In the case of the coating method, any material may be used as long as it can be dissolved or dispersed in the liquid medium used in electrode production, and specific examples include polyethylene, polypropylene, polyethylene terephthalate, polymethyl methacrylate, aromatic polyamide, cellulose, nitro Resin-based polymers such as cellulose; SBR (styrene-butadiene rubber), NBR (acrylonitrile-butadiene rubber), fluororubber, isoprene rubber, butadiene rubber, rubber-like polymers such as ethylene-propylene rubber; styrene-butadiene-styrene block Copolymer or its hydrogenated substance, EPDM (ethylene-propylene-diene terpolymer), styrene-ethylene-butadiene-ethylene copolymer, styrene-isoprene-styrene block copolymer or its hydrogenated substance Thermoplastic Stomer polymers; soft resinous polymers such as syndiotactic 1,2-polybutadiene, polyvinyl acetate, ethylene / vinyl acetate copolymer, propylene / α-olefin copolymer, etc. polyvinylidene fluoride (PVdF), Examples thereof include fluorine-based polymers such as polytetrafluoroethylene, fluorinated polyvinylidene fluoride, and polytetrafluoroethylene-ethylene copolymers; and polymer compositions having ion conductivity of alkali metal ions (particularly lithium ions). One of these substances may be used alone, or two or more of these substances may be used in any combination and ratio.

  The proportion of the binder in the positive electrode active material layer is usually 0.1% by mass or more, preferably 1% by mass or more, more preferably 3% by mass or more, and usually 50% by mass or less, and 30% by mass. % Or less is preferable, 10% by mass or less is more preferable, and 8% by mass or less is particularly preferable. When the proportion of the binder is within the above range, the positive active substance can be sufficiently retained, the mechanical strength of the positive electrode can be maintained, and it is preferable from the viewpoint of cycle characteristics, battery capacity and conductivity.

(4) Liquid Medium The liquid medium for forming the slurry may be a solvent capable of dissolving or dispersing the positive electrode active material, the conductive material, the binder, and the thickener used if necessary. For example, the type thereof is not particularly limited, and either an aqueous solvent or an organic solvent may be used.
Examples of the aqueous medium include water, a mixed medium of alcohol and water, and the like. Examples of the organic medium include aliphatic hydrocarbons such as hexane; aromatic hydrocarbons such as benzene, toluene, xylene and methyl naphthalene; heterocyclic compounds such as quinoline and pyridine; ketones such as acetone, methyl ethyl ketone and cyclohexanone Esters such as methyl acetate and methyl acrylate; Amines such as diethylenetriamine and N, N-dimethylaminopropylamine; Ethers such as diethyl ether and tetrahydrofuran (THF); N-methylpyrrolidone (NMP) and dimethylformamide And amides such as dimethylacetamide; aprotic polar solvents such as hexamethylphosphaamide and dimethyl sulfoxide, and the like. In addition, these may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.

(5) Thickener When using an aqueous medium as a liquid medium for forming a slurry, it is preferable to use a thickener and a latex such as styrene butadiene rubber (SBR) to make a slurry. Thickeners are usually used to adjust the viscosity of the slurry.
The thickener is not particularly limited as long as the effects of the present invention are not significantly limited, and specifically, carboxymethylcellulose, methylcellulose, hydroxymethylcellulose, ethylcellulose, polyvinyl alcohol, oxidized starch, phosphorylated starch, casein and salts thereof Etc. One of these may be used alone, or two or more of these may be used in any combination and ratio.

  Furthermore, when a thickener is used, the ratio of the thickener to the active material is usually 0.1% by mass or more, preferably 0.5% by mass or more, more preferably 0.6% by mass or more, Usually, 5% by mass or less, preferably 3% by mass or less, more preferably 2% by mass or less is desirable. If the above range is exceeded, the coatability may be significantly reduced. If the above range is exceeded, the proportion of the active material in the positive electrode active material layer is reduced, and the capacity of the battery is reduced. May increase.

(6) Consolidation The positive electrode active material layer obtained by coating and drying is preferably consolidated by a hand press, a roller press or the like in order to increase the packing density of the positive electrode active material. The density of the positive electrode active material layer is preferably 1 g · cm ³ or more, more preferably 1.5 g · cm ³ or more, particularly preferably 2 g · cm ³ or more, and preferably 4 g · cm ³ or less, 3.5 g · cm ⁻³ or less is more preferable, and 3 g · cm ⁻³ or less is particularly preferable.
If the density of the positive electrode active material layer exceeds the above range, the permeability of the non-aqueous electrolytic solution to the vicinity of the current collector / active material interface may be reduced, and in particular, the charge and discharge characteristics at high current density may be reduced. Moreover, if it is less than the said range, the conductivity between active materials may fall and battery resistance may increase.

(7) Current collector The material of the positive electrode current collector is not particularly limited, and any known material can be used. Specific examples thereof include metal materials such as aluminum, stainless steel, nickel plating, titanium and tantalum; and carbonaceous materials such as carbon cloth and carbon paper. Among them, metal materials, particularly aluminum, are preferred.

  Examples of the shape of the current collector include metal foil, metal cylinder, metal coil, metal plate, metal thin film, expanded metal, punched metal, foamed metal and the like in the case of a metal material, and in the case of a carbonaceous material, a carbon plate, A carbon thin film, a carbon cylinder, etc. are mentioned. Of these, metal thin films are preferred. The thin film may be formed in a mesh shape as appropriate.

  The thickness of the current collector is arbitrary but is usually 1 μm or more, preferably 3 μm or more, more preferably 5 μm or more, and usually 1 mm or less, preferably 100 μm or less, and more preferably 50 μm or less. If the thin film is within the above range, the strength necessary for the current collector can be maintained, and it is also preferable from the viewpoint of handleability.

The ratio of the thickness of the current collector to the thickness of the positive electrode active material layer is not particularly limited, but the value of (thickness of positive electrode active material layer on one side immediately before pouring of electrolyte) / (thickness of current collector) is Usually 20 or less, preferably 15 or less
More preferably, it is 10 or less, and a lower limit is usually 0.5 or more, preferably 0.8 or more, more preferably 1 or more. If this range is exceeded, the current collector may generate Joule heat during high current density charge and discharge. Below this range, the volume ratio of the current collector to the positive electrode active material may increase, and the capacity of the battery may decrease.

<2-5. Separator>
In order to prevent a short circuit, a separator is usually interposed between the positive electrode and the negative electrode. In this case, the non-aqueous electrolytic solution of the present invention is usually used by impregnating this separator.
There is no particular limitation on the material and shape of the separator, and any known one can be adopted as long as the effects of the present invention are not significantly impaired. Among them, resins, glass fibers, inorganic substances, etc., which are made of a material stable to the non-aqueous electrolyte solution of the present invention, are used, and porous sheet or non-woven fabric-like articles etc. excellent in liquid retention are used. Is preferred.

  As a material of resin and a glass fiber separator, polyolefin, such as polyethylene and a polypropylene, a polytetrafluoroethylene, a polyether sulfone, a glass filter etc. can be used, for example. Among them, preferred are glass filters and polyolefins, and more preferred are polyolefins. One of these materials may be used alone, or two or more of these materials may be used in any combination and ratio.

  The thickness of the separator is arbitrary but is usually 1 μm or more, preferably 5 μm or more, more preferably 10 μm or more, and usually 50 μm or less, preferably 40 μm or less, still more preferably 30 μm or less. If the separator is thinner than the above range, the insulation and mechanical strength may be reduced. When the thickness is more than the above range, not only the battery performance such as rate characteristics may be degraded, but also the energy density of the whole non-aqueous electrolyte secondary battery may be degraded.

  Furthermore, when a porous sheet such as a porous sheet or a non-woven fabric is used as the separator, the porosity of the separator is optional, but is usually 20% or more, preferably 35% or more, and more preferably 45% or more, Also, it is usually 90% or less, preferably 85% or less, and more preferably 75% or less. When the porosity is smaller than the above range, the film resistance tends to be increased and the rate characteristic tends to be deteriorated. Moreover, when it is larger than the said range, it exists in the tendency for the mechanical strength of a separator to fall and for insulation to fall.

The average pore diameter of the separator is also optional, but is usually 0.5 μm or less, preferably 0.2 μm or less, and usually 0.05 μm or more. When the average pore size exceeds the above range, a short circuit is likely to occur. If the above range is exceeded, the film resistance may increase and the rate characteristics may deteriorate.
On the other hand, as the inorganic material, for example, oxides such as alumina and silicon dioxide, nitrides such as aluminum nitride and silicon nitride, and sulfates such as barium sulfate and calcium sulfate are used. Are used.

  As the form, a thin film such as a non-woven fabric, a woven fabric and a microporous film is used. In the thin film form, one having a pore diameter of 0.01 to 1 μm and a thickness of 5 to 50 μm is suitably used. A separator formed by forming a composite porous layer containing particles of the inorganic substance on the surface layer of the positive electrode and / or the negative electrode using a binder made of resin other than the above-mentioned independent thin film shape can be used. For example, alumina particles having a 90% particle size of less than 1 μm may be formed on both sides of the positive electrode to form a porous layer using a fluorine resin as a binder.

<2-6. Battery design>
[Electrode group]
The electrode group has a laminated structure in which the positive electrode plate and the negative electrode plate described above are interposed with the separator described above, or a structure in which the positive electrode plate and the negative electrode plate described above are spirally wound with the separator interposed therebetween. Any may be used. The ratio of the volume of the electrode group to the internal volume of the battery (hereinafter referred to as the electrode group occupancy rate) is usually 40% or more, preferably 50% or more, and usually 90% or less, preferably 80% or less . When the electrode group occupancy rate falls below the above range, the battery capacity decreases. Further, when the above range is exceeded, the void space is small, the battery becomes high temperature, the members expand, the vapor pressure of the liquid component of the electrolyte becomes high, and the internal pressure rises, and the charge and discharge repetition performance as the battery And may deteriorate various characteristics such as high temperature storage, and may further operate a gas release valve that releases the internal pressure to the outside.

[Current collection structure]
Although the current collection structure is not particularly limited, in order to more effectively realize the improvement of the discharge characteristics by the non-aqueous electrolyte solution of the present invention, it is possible to reduce the resistance of the wiring portion and the bonding portion. preferable. When the internal resistance is reduced as described above, the effect of using the non-aqueous electrolyte solution of the present invention is particularly well exhibited.

  When the electrode group has the above-described laminated structure, a structure in which the metal core portions of the respective electrode layers are bundled and welded to the terminal is preferably used. When the area of one electrode increases, the internal resistance increases. Therefore, it is also preferable to provide a plurality of terminals in the electrode to reduce the resistance. When the electrode group has the above-described wound structure, the internal resistance can be reduced by providing a plurality of lead structures on the positive electrode and the negative electrode and bundling them in the terminals.

[Exterior case]
The material of the outer case is not particularly limited as long as the material is stable to the non-aqueous electrolyte used. Specifically, a nickel-plated steel sheet, metals such as stainless steel, aluminum or aluminum alloy, magnesium alloy or the like, or a laminated film (laminated film) of a resin and an aluminum foil is used. From the viewpoint of weight reduction, metals of aluminum or aluminum alloy and laminate films are preferably used.

  In the outer case using the metals, the metals are welded together by laser welding, resistance welding, ultrasonic welding to form a hermetically sealed structure, or a caulking structure using the metals through a resin gasket. The thing to do is mentioned. In the outer case using the laminate film, those having a sealing and sealing structure by thermally fusing the resin layers to each other may be mentioned. A resin different from the resin used for the laminate film may be interposed between the resin layers in order to improve the sealability. In particular, in the case where the resin layer is heat-sealed through the current collection terminal to form a sealed structure, the metal and the resin are joined, and therefore, a resin having a polar group or a modification having a polar group introduced as an intervening resin Resin is preferably used.

[Protective element]
As the above-mentioned protective element, PTC (Positive Temperature Coefficient), which has an increase in resistance when abnormal heat generation or excessive current flows, thermal fuse, thermistor, current flowing in the circuit due to rapid increase in internal pressure of battery or internal temperature at abnormal heat generation. Valve (current cut-off valve) etc. which cut off. The protective element is preferably selected under conditions which do not operate under normal use of a high current, and from the viewpoint of high output, it is more preferable to design it not to lead to abnormal heat generation or thermal runaway without a protective element.

[Exterior body]
The non-aqueous electrolyte secondary battery of the present invention is usually constructed by housing the above-described non-aqueous electrolyte, negative electrode, positive electrode, separator and the like in an outer package. The outer package is not limited, and any known one can be adopted as long as the effects of the present invention are not significantly impaired.
Specifically, the material of the outer package is optional, but normally, for example, nickel-plated iron, stainless steel, aluminum or an alloy thereof, nickel, titanium or the like is used.
Further, the shape of the outer package is also arbitrary, and may be, for example, any of cylindrical, square, laminate, coin, large size and the like.

Example 1
EXAMPLES The present invention will be more specifically described below with reference to examples and comparative examples, but the present invention is not limited to these examples.

[Fabrication of negative electrode]
In 98 parts by mass of a carbonaceous material, 1 part by mass of an aqueous dispersion of sodium carboxymethylcellulose (concentration of 1% by mass of sodium carboxymethylcellulose) as a thickener and a binder, and an aqueous dispersion of styrene-butadiene rubber (styrene-butadiene rubber 1 part by mass of a concentration of 50% by mass) was added and mixed with a disperser to form a slurry. The obtained slurry is applied to a copper foil with a thickness of 10 μm, dried, and rolled with a press, and the size of the active material layer is not coated: width 30 mm, length 40 mm, width 5 mm, length 9 mm It cut out to the shape which has a part, and was set as the negative electrode.

[Production of positive electrode]
67.5 mass% of lithium manganate (Li _1.1 Mn _1.9 Al _0.1 O ₄ ) and 22.5 mass of LiNi _0.33 Mn _0.33 Co _0.33 O ₂ as a positive electrode active material %, 5% by mass of acetylene black as a conductive material, and 5% by mass of polyvinylidene fluoride (PVdF) as a binder were mixed in an N-methylpyrrolidone solvent to form a slurry. The obtained slurry is applied on one side of a 15 μm thick aluminum foil coated with a conductive aid in advance, dried, and roll-pressed with a press. The size of the active material layer is 30 mm in width, length. It cut out to the shape which has an uncoated part of 40 mm and width 5 mm and length 9 mm, and it was set as the positive electrode.

[Preparation of electrolyte solution]
The mixture of ethylene carbonate (EC), dimethyl carbonate (DMC) and ethyl methyl carbonate (EMC) in a dry argon atmosphere (volume ratio 30:30:40) is a ratio of 1.15 mol / L of dried LiPF ₆ The base electrolyte was prepared by dissolving as above. In this basic electrolytic solution, 0.3 parts by mass of lithium bis (oxalate) borate (LiBOB) and 0.3 parts by mass of succinic anhydride (SUC) were mixed to prepare an electrolytic solution used in Example 1.

[Manufacturing of lithium secondary battery]
The positive electrode, the negative electrode, and the polyethylene separator were laminated in the order of the negative electrode, the separator and the positive electrode to produce a battery element. The battery element is inserted into a bag made of a laminated film in which both sides of aluminum (thickness 40 μm) are coated with a resin layer, with the terminals of the positive electrode and the negative electrode protruding. It sealed and produced the sheet-like battery which will be in a full charge state at 4.2V.

[Evaluation of initial discharge capacity]
While charging the lithium secondary battery between the glass plates in order to enhance the adhesion between the electrodes, after charging to 4.2 V at a constant current equivalent to 0.2 C at 25 ° C., a constant current of 0.2 C Discharge to 2.7V. This is done 2 cycles to stabilize the battery, and in the third cycle, after charging to 4.2 V with a constant current of 0.2 C, charge to a current value of 0.05 C with a constant voltage of 4.2 V , And was discharged to 2.7 V at a constant current of 0.2C. Thereafter, in the fourth cycle, after charging to 4.2 V with a constant current of 0.2 C, charging is performed at a constant voltage of 4.2 V until the current value reaches 0.05 C. It discharged to 7 V and calculated | required initial stage discharge capacity.

[Evaluation of initial -10 ° C regeneration]
The battery in which the evaluation of the initial discharge capacity was finished was charged at 25 ° C. at a constant current of 0.2 C so as to be half the initial discharge capacity. This was charged at 0.5C, 1.0C, 1.5C, 2C, and 2.5C at -10 ° C, and the voltage at 10 seconds was measured. The current value at 4.2 V was determined from the current-voltage line, and 4.2 × (current value at 4.2 V) was taken as the output (W).

[Evaluation of high temperature storage characteristics]
The battery after the initial discharge capacity evaluation test was charged to 4.2 V with a constant current of 0.2 C and then charged to a current value of 0.05 C with a constant voltage of 4.2 V. The battery was stored at 60 ° C. for 7 days, cooled to room temperature, and discharged to 2.7 V at a constant current of 0.2 C at 25 ° C. to determine the remaining capacity. The storage capacity retention rate (%) was determined from (remaining capacity) / (initial discharge capacity) × 100. A result is shown in Table 1 (the relative value at the time of setting comparative example 1 to 100.0 is shown).

[Evaluation of -10 ° C regeneration after high temperature storage]
After the evaluation of the high temperature storage characteristics was completed, the battery was charged at 25 ° C. at a constant current of 0.2 C to a half of the initial discharge capacity. This was charged at 0.5C, 1.0C, 1.5C, 2C, and 2.5C at -10 ° C, and the voltage at 10 seconds was measured. The current value at 4.2 V was determined from the current-voltage line, and 4.2 × (current value at 4.2 V) was taken as the output (W). The storage regeneration retention rate (%) was determined from (high temperature storage −10 ° C. regeneration) × (initial −10 ° C. regeneration) × 100. A result is shown in Table 1 (the relative value at the time of setting comparative example 1 to 100.0 is shown).

Example 2
Example 1 was repeated except that 0.5 parts by mass of lithium bis (oxalate) borate (LiBOB) and 0.3 parts by mass of succinic anhydride (SUC) were mixed in the basic electrolyte used in Example 1. Then, a sheet-like lithium secondary battery was produced and evaluated. The results are shown in Table 1.

Example 3
Example 1 was repeated except that 0.5 parts by mass of lithium bis (oxalate) borate (LiBOB) and 0.5 parts by mass of succinic anhydride (SUC) were mixed in the basic electrolyte used in Example 1. Then, a sheet-like lithium secondary battery was produced and evaluated. The results are shown in Table 1.

Example 4
Example except that 0.5 parts by mass of lithium difluorobis (oxalate) phosphate (LiF2OP) and 0.5 parts by mass of methacrylic anhydride (MP1) were mixed in the basic electrolytic solution used in Example 1. A sheet-like lithium secondary battery was produced in the same manner as 1 and evaluated. The results are shown in Table 1.

Example 5
The mixture of ethylene carbonate (EC), dimethyl carbonate (DMC) and ethyl methyl carbonate (EMC) in a dry argon atmosphere (volume ratio 30:30:40) is a ratio of 0.6 mol / L of dried LiPF ₆ The base electrolyte was prepared by dissolving as above. Sheet-like lithium was prepared in the same manner as Example 1, except that 1.0 part by mass of lithium bis (oxalate) borate (LiBOB) and 0.3 parts by mass of succinic anhydride (SUC) were mixed in this basic electrolytic solution. A secondary battery was produced and evaluated. The results are shown in Table 1.

Comparative Example 1
Lithium bis (oxalate) borate (LiBOB) was used as the basic electrolyte used in Example 1.
A sheet-like lithium secondary battery was produced and evaluated in the same manner as in Example 1 except that 0.5 parts by mass of A) was mixed. The results are shown in Table 1.

Comparative example 2
A sheet-like lithium secondary battery was produced and evaluated in the same manner as in Example 1 except that 0.3 parts by mass of succinic anhydride (SUC) was mixed with the basic electrolyte used in Example 1. The results are shown in Table 1.

Comparative example 3
The same procedure as in Example 1 was repeated except that 0.5 parts by mass of lithium bis (oxalate) borate (LiBOB) and 0.3 parts by mass of vinylene carbonate (VC) were mixed in the basic electrolyte used in Example 1. A sheet-like lithium secondary battery was produced and evaluated. The results are shown in Table 1.

Comparative example 4
Example 1 was repeated except that 1.6 parts by mass of lithium bis (oxalate) borate (LiBOB) and 0.5 parts by mass of succinic anhydride (SUC) were mixed in the basic electrolytic solution used in Example 1. Then, a sheet-like lithium secondary battery was produced and evaluated. The results are shown in Table 1.

Comparative example 5
Example 1 is similar to Example 1 except that 1.6 parts by mass of lithium bis (oxalate) borate (LiBOB) and 0.3 parts by mass of succinic anhydride (SUC) are mixed in the basic electrolyte used in Example 5. Then, a sheet-like lithium secondary battery was produced and evaluated. The results are shown in Table 1.

Comparative example 6
Example 1 is similar to Example 1 except that 0.5 parts by mass of lithium bis (oxalate) borate (LiBOB) and 1.3 parts by mass of succinic anhydride (SUC) are mixed in the basic electrolyte used in Example 5. Then, a sheet-like lithium secondary battery was produced and evaluated. The results are shown in Table 1.

Comparative example 7
The mixture of ethylene carbonate (EC), dimethyl carbonate (DMC) and ethyl methyl carbonate (EMC) in a dry argon atmosphere (volume ratio 30:30:40) is a ratio of 1.6 mol / L of dried LiPF ₆ The base electrolyte was prepared by dissolving as above. Sheet-like lithium was prepared in the same manner as in Example 1, except that 0.15 parts by mass of lithium bis (oxalate) borate (LiBOB) and 0.15 parts by mass of succinic anhydride (SUC) were mixed in this basic electrolytic solution. A secondary battery was produced and evaluated. The results are shown in Table 1.

Comparative Example 8
Example 6 is the same as Example 1 except that 0.3 parts by mass of lithium bis (oxalate) borate (LiBOB) and 1.3 parts by mass of succinic anhydride (SUC) are mixed in the basic electrolyte used in Comparative Example 7. Then, a sheet-like lithium secondary battery was produced and evaluated. The results are shown in Table 1.

Example 6
[Production of positive electrode]
90% by mass of LiNi _0.33 Mn _0.33 Co _0.33 O ₂ as a positive electrode active material, 5% by mass of acetylene black as a conductive material, 5% by mass of polyvinylidene fluoride (PVdF) as a binder Were mixed in N-methyl pyrrolidone solvent and slurried. The obtained slurry is applied on one side of a 15 μm thick aluminum foil coated with a conductive aid in advance, dried, and roll-pressed with a press. The size of the active material layer is 30 mm in width, length. It cut out to the shape which has an uncoated part of 40 mm and width 5 mm and length 9 mm, and it was set as the positive electrode.

[Preparation of electrolyte solution]
The mixture of ethylene carbonate (EC), dimethyl carbonate (DMC) and ethyl methyl carbonate (EMC) in a dry argon atmosphere (volume ratio 30:30:40) is a ratio of 1.2 mol / L of dried LiPF ₆ The base electrolyte was prepared by dissolving as above. In this basic electrolyte, 0.6 parts by mass of lithium bis (oxalate) borate (LiBOB), 0.5 parts by mass of lithium difluorophosphate (LiPO ₂ F ₂ ), and 0.5 parts of vinylene carbonate (VC) The parts by mass and 0.4 parts by mass of succinic anhydride (SUC) were mixed.

[Manufacturing of lithium secondary battery]
A sheet-like lithium secondary battery was produced in the same manner as in Example 1 except that the above-described positive electrode and electrolytic solution were used.

[Evaluation of initial discharge capacity]
While charging the lithium secondary battery between the glass plates in order to enhance the adhesion between the electrodes, after charging to 4.2 V at a constant current equivalent to 0.2 C at 25 ° C., a constant current of 0.2 C Discharge to 3.0V. This is done 2 cycles to stabilize the battery, and in the third cycle, after charging to 4.2 V with a constant current of 0.2 C, charge to a current value of 0.05 C with a constant voltage of 4.2 V And was discharged to 3.0 V with a constant current of 0.2C. Thereafter, in the fourth cycle, after charging to 4.2 V with a constant current of 0.2 C, charging is performed at a constant voltage of 4.2 V until the current value reaches 0.05 C, and 3. It discharged to 0 V and calculated | required initial stage discharge capacity.

[Evaluation of initial -30 ° C output]
The battery in which the evaluation of the initial discharge capacity was finished was charged at 25 ° C. at a constant current of 0.2 C so as to be half the initial discharge capacity. This was discharged at -30 ° C at 0.5C, 1.0C, 1.5C, 2C and 2.5C, respectively, and the voltage at 10 seconds was measured. The current value at 3.0 V was determined from the current-voltage line, and 3.0 × (current value at 3.0 V) was taken as the output (W).

[Evaluation of high temperature storage characteristics]
The battery after the initial discharge capacity evaluation test was charged to 4.2 V with a constant current of 0.2 C and then charged to a current value of 0.05 C with a constant voltage of 4.2 V. The battery was stored at 60 ° C. for 28 days, cooled to room temperature, and discharged to 2.7 V at a constant current of 0.2 C at 25 ° C. to determine the remaining capacity. The storage capacity retention rate (%) was determined from (remaining capacity) / (initial discharge capacity) × 100. A result is shown in Table 2 (the relative value at the time of setting comparative example 9 to 100.0 is shown).

[Evaluation of -30 ° C regeneration after high temperature storage]
After the evaluation of the high temperature storage characteristics was completed, the battery was charged at 25 ° C. at a constant current of 0.2 C to a half of the initial discharge capacity. This was discharged at -30 ° C at 0.5C, 1.0C, 1.5C, 2C and 2.5C, respectively, and the voltage at 10 seconds was measured. The current value at 3.0 V was determined from the current-voltage line, and 3.0 × (current value at 3.0 V) was taken as the output (W). The storage power retention ratio (%) was determined from (high temperature storage −30 ° C. output) × (initial −30 ° C. output) × 100. A result is shown in Table 2 (the relative value at the time of setting comparative example 9 to 100.0 is shown).

Example 7
In the basic electrolyte used in Example 6, 0.6 parts by mass of lithium bis (oxalate) borate (LiBOB), 0.5 parts by mass of lithium difluorophosphate (LiPO ₂ F ₂ ), and vinylene carbonate (VC) A sheet-like lithium secondary battery was produced and evaluated in the same manner as in Example 6 except that 0.5 parts by mass of M.2) and 0.4 parts by mass of methacrylic anhydride (MP1) were mixed. The results are shown in Table 2.

Comparative Example 9
In the basic electrolyte used in Example 6, 0.6 parts by mass of lithium bis (oxalate) borate (LiBOB), 0.5 parts by mass of lithium difluorophosphate (LiPO ₂ F ₂ ), and vinylene carbonate (VC) A sheet-like lithium secondary battery was produced and evaluated in the same manner as in Example 6 except that 0.5 parts by mass of A) was mixed. The results are shown in Table 2.

As apparent from the above Examples and Comparative Examples, the mass% of LiPF ₆ with respect to the whole non-aqueous electrolytic solution is [A], the mass% of lithium oxalate salt is [B], and the following General Formula (1) Where the mass% of the compound to be
(A) [A] / [B] is 5 or more and 90 or less (b) [B] ≧ [C] and [B] + [C] <2.0 mass%
It is understood that Examples 1 to 7 satisfying the above are excellent in both the capacity retention rate after battery endurance and the output regeneration characteristic.

Therefore, in Examples 1 to 7 satisfying the above range, a higher effect is exhibited than Comparative Example 1 containing the lithium oxalate salt alone and Comparative Example 2 containing SUC alone, and the lithium oxalate salt Specific effects that can not be imagined are exhibited from single content or SUC single content. Among the conditions of Comparative Example 3 and Comparative Example 9, which do not contain the compound represented by the general formula (1), such an effect is the condition of [B] + [C] <2.0 mass% among the conditions of (b) Among the conditions of Comparative Example 4 and Comparative Example 5 and Comparative Example 7 not satisfying the conditions of (a), and Comparative Example 7 and Comparative Example 7 of (b), the expression is obtained in Comparative Example 6 and Comparative Example 8 not satisfying [B] ≧ [C]. It has not been.
Although the invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.

According to the non-aqueous electrolyte solution of the present invention, the initial charge capacity and input / output characteristics of the non-aqueous electrolyte secondary battery can be improved. The non-aqueous electrolyte secondary battery using the non-aqueous electrolyte solution of the present invention has a high capacity retention rate and excellent input / output performance even after a durability test such as a high temperature storage test or a cycle test. The output characteristics are also excellent and useful. Therefore, the non-aqueous electrolytic solution of the present invention and the non-aqueous electrolytic solution secondary battery using the same can be used for various known applications. Specific examples are, for example, a laptop computer, a pen input computer, a mobile computer, an e-book player, a mobile phone, a mobile fax, a mobile copy, a mobile printer, a headphone stereo, a video movie, an LCD television, a handy cleaner, a portable C
D, mini disk, transceiver, electronic organizer, calculator, memory card, portable tape recorder, radio, backup power supply, motor, automobile, bike, motorized bicycle, bicycle, lighting equipment, toy, game machine, watch, electric tool, strobe , Cameras, load leveling power sources, natural energy storage power sources, lithium ion capacitors, and the like.

Claims (8)

A non-aqueous electrolytic solution comprising a non-aqueous solvent, LiPF ₆ , lithium oxalate salt, and a compound represented by the following general formula (1), wherein the mass% of LiPF ₆ with respect to the entire non-aqueous electrolytic solution is [A], The mass% of the lithium oxalate salt is [B], and the mass% of the compound represented by the following general formula (1) (with the exception of the cyclic acid anhydride containing a side chain having allyl hydrogen) [C]
When you
(A) [A] / [B] is 5 or more and 90 or less (b) [B] [[C] and [B] + [C] < 1.8 mass%
Non-aqueous electrolyte that meets

(In the general formula (1), R ¹ and R ² each independently may have a substituent and represent a hydrocarbon group having a carbon number of 15 or less. R ¹ and R ² are bonded to each other And may form an annular structure) The compound represented by the general formula (1) is bonded with R ^1, R ² each other, characterized in that to form a cyclic structure, a non-aqueous electrolyte solution of claim 1. The non-aqueous electrolytic solution according to claim 1, wherein the compound represented by the general formula (1) is a chain compound. Lithium oxalate salt is a group consisting of lithium bis (oxalate) borate, lithium difluoro (oxalate) borate, lithium tris (oxalate) phosphate, lithium difluoro bis (oxalate) phosphate, lithium tetrafluoro (oxalate) phosphate The non-aqueous electrolytic solution according to any one of claims 1 to 3, characterized in that it is at least one or more. A non-aqueous electrolyte secondary battery comprising a negative electrode and a positive electrode capable of storing and releasing lithium ions, and the non-aqueous electrolyte solution according to any one of claims 1 to 4. The negative electrode has a negative electrode active material layer on a current collector, and the negative electrode active material layer is a single metal, an alloy and a compound of silicon, a single metal, an alloy and a compound of tin, a carbonaceous material, and a lithium titanium composite The non-aqueous electrolyte secondary battery according to claim 5, comprising a negative electrode active material containing at least one of oxides. The positive electrode has a positive electrode active material layer on a current collector, and the positive electrode active material layer is a lithium-cobalt composite oxide, a lithium-cobalt-nickel composite oxide, a lithium-manganese composite oxide, lithium-cobalt · Characterized in that it contains at least one selected from the group consisting of manganese composite oxides, lithium-nickel composite oxides, lithium-nickel-manganese composite oxides, lithium-cobalt-nickel-manganese composite oxides, Item 5 or 6
The non-aqueous electrolyte secondary battery as described in. The positive electrode has a positive electrode active material layer on a current collector, and the positive electrode active material layer is formed of LixMPO ₄ (
M = at least one element selected from the group consisting of transition metals of Groups 4 to 11 of the 4th period of the periodic table, and x contains 0 <x <1.2). 7. The non-aqueous electrolyte secondary battery according to any one of 7.