JP2002110234A - Non-aqueous electrolytic solution and lithium secondary battery using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lithium secondary battery superior in battery characteristics including a cycle characteristic, electric capacity and a shelf life characteristic. SOLUTION: The lithium secondary battery comprises a positive electrode, a negative electrode and a non-aqueous electrolytic solution having an electrolyte dissolved in a non-aqueous solvent. The positive electrode is formed of a material containing a lithium composite oxide, the negative electrode is formed of a material containing graphite, and the non-aqueous solvent contains dominantly cyclic carbonate and chain carbonate where the non-aqueous electrolytic solution contains a 0.001-0.8 wt.% alkoxybenzene derivative such as 1,2,4- trimethoxybenzene and a 0.1-10 wt.% alkyne derivative such as methane sulfonic acid 2-propynyl.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-aqueous electrolyte capable of providing a lithium secondary battery having excellent battery characteristics such as cycle characteristics, electric capacity and storage characteristics of a battery, and lithium using the same. Related to secondary batteries.

[0002]

2. Description of the Related Art In recent years, lithium secondary batteries have been widely used as power sources for driving small electronic devices and the like. Lithium secondary batteries are mainly composed of a positive electrode, a non-aqueous electrolyte, and a negative electrode. In particular, a lithium secondary battery using a lithium composite oxide such as LiCoO ₂ as a positive electrode and a carbon material or lithium metal as a negative electrode has been developed. It is preferably used. As the non-aqueous electrolyte for the lithium secondary battery, ethylene carbonate (EC), propylene carbonate (P
C), dimethyl carbonate (DMC), diethyl carbonate (DEC), methyl ethyl carbonate (ME
Carbonates such as C) are preferably used.

[0003] However, there is a demand for a secondary battery having more excellent battery characteristics such as cycle characteristics and storage characteristics. In a lithium secondary battery using a highly crystallized carbon material such as natural graphite or artificial graphite as the negative electrode, peeling of the carbon negative electrode material is observed, and the capacity may be irreversible depending on the degree of the phenomenon. This peeling is caused by the decomposition of the solvent in the electrolytic solution at the time of charging, and is caused by the electrochemical reduction of the solvent at the interface between the carbon anode material and the electrolytic solution. Among them, an electrolytic solution using a PC having a low melting point and a high dielectric constant has high electric conductivity even at a low temperature, but when a graphite negative electrode is used, the decomposition of the PC occurs and cannot be used for a lithium secondary battery. There was a problem. Also, EC is partially decomposed during repeated charge and discharge, and the battery performance is reduced. Therefore, at present, the battery characteristics such as the cycle characteristics and the electric capacity of the battery are not always satisfactory.

The present inventors have solved the above-mentioned problems relating to the electrolyte solution for a lithium secondary battery and constructed a lithium battery having excellent cycle characteristics and excellent battery characteristics such as storage characteristics. Electrolyte for a lithium secondary battery, and for the purpose of providing a lithium secondary battery using the same, wherein an alkyne derivative is contained in a non-aqueous electrolyte for a lithium secondary battery. And a lithium secondary battery using the same were proposed (JP-A-2000-195545). In the above proposal, the alkyne derivative contained in the electrolytic solution is:
Decompose before the non-aqueous solvent in the electrolyte on the surface of the carbon negative electrode during charging, and a part of the decomposition product forms a passive film on the highly crystallized active carbon negative electrode surface such as natural graphite or artificial graphite. Thus, it is estimated that reductive decomposition of the non-aqueous solvent in the electrolytic solution is prevented beforehand.

[0005] However, when the lithium secondary battery of the above proposal is charged and discharged under severe conditions, for example, charge and discharge are repeated to a maximum operating voltage exceeding 4.1 V, such as 4.3 V, for a long period of time. It has been found that when the battery is charged and discharged for a long time at a high temperature exceeding 40 ° C., the capacity gradually decreases. This phenomenon occurs because, for example, LiCoO ₂ , LiMn ₂ O ₄ , LiNi
In a lithium secondary battery using O ₂ or the like, when charge and discharge are repeated up to a maximum operating voltage exceeding 4.1 V, a part of the solvent in the non-aqueous electrolyte is locally oxidatively decomposed, and the decomposed product is a battery. This impairs the electrochemical performance of the battery due to the inhibition of the desired electrochemical reaction, which may be due to the electrochemical oxidation of the solvent at the interface between the cathode material and the non-aqueous electrolyte. Therefore, even under such severe conditions, it is desired to provide a non-aqueous electrolyte having more excellent cycle characteristics and excellent battery characteristics such as storage characteristics, and a lithium secondary battery using the same. I have.

On the other hand, JP-A-7-302614 discloses that 1,3,5-trimethoxybenzene or the like is used in an amount of 0.1 to 0.1.
A technique has been proposed in which, by adding 0.25 M (mol / liter), a redox shuttle consumes an overcharge current at the time of overcharge, suppresses a rise in voltage, and protects the battery from overcharge. However, in a lithium secondary battery using a highly crystallized carbon material such as natural graphite or artificial graphite as a negative electrode, good charge / discharge is repeated even in 100 cycles in charge / discharge at 4.1-2.5V. However, in severe charge / discharge such as a high voltage of 4.3 V and / or a high temperature state of 40 ° C. or higher, the cycle characteristics were low.

[0007] JP-A-9-106835 discloses that
By adding about 1 to 4% by volume of 2-dimethoxybenzene, biphenyl, thiophene, furan and the like, electrochemical polymerization is performed at an abnormally high voltage when overcharging occurs, thereby increasing the resistance of the electrolyte. Battery protection technology has been disclosed. However, 1,2-dimethoxybenzene is
It is described that the cycle life is adversely affected and is not suitable, and satisfactory cycle characteristics are not obtained.

[0008] JP-A-10-64591 discloses Li
BF ₄ and / or the electrolyte solution using the support salt was dissolved LiPF ₆ 1,4-dimethoxybenzene, etc. 1,2-methylenedioxybenzene by adding 0.1 to 50 mm (mmol / l), It is described that the capacity and the cycle characteristics are improved. However, when a highly crystallized carbon material such as natural graphite or artificial graphite is used as the negative electrode, the nonaqueous solvent used as the electrolyte is partially decomposed on the carbon negative electrode together with the number of charge / discharge cycles of the battery. As a result, there is a problem that the decomposition product is gradually deposited on the negative electrode and the battery capacity is gradually reduced. Among them, an electrolytic solution using a PC having a low melting point and a high dielectric constant has high electric conductivity even at a low temperature, but when a graphite negative electrode is used, the PC is decomposed and cannot be used for a lithium battery. There was a point. Also, EC is partially decomposed during repeated charge and discharge, and the battery performance is reduced. For this reason, at present, battery characteristics such as cycle characteristics and storage characteristics of batteries are not always satisfactory.

JP-A-2000-156243 discloses diphenyl, naphthalene, 4-fluoroanisole, 1,2-dimethoxybenzene, 4-fluoro-1,
An organic compound having a reversible oxidation-reduction potential of 0.5 M (mole / liter) is added to a battery potential, such as 2-dimethoxybenzene, which is more noble than the positive electrode potential at the time of full charge, and is oxidized when overcharged. There has been proposed a method in which decomposition is promoted to generate a polymer, an overcharge current is cut off, and heat generation of the battery is suppressed. However, these additives have 4.3
In charge and discharge at a high voltage such as V and / or at a high temperature of 40 ° C. or higher, the cycle characteristics were low.

[0010]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems relating to the decomposition of the electrolyte for a lithium secondary battery at the positive electrode and the negative electrode at the same time. An object of the present invention is to provide a non-aqueous electrolyte for a lithium secondary battery that can constitute a lithium secondary battery having excellent battery characteristics such as storage characteristics in a state, and a lithium secondary battery using the same. I do.

[0011]

Means for Solving the Problems The present inventors have solved the above-mentioned problems relating to the electrolyte for a lithium secondary battery,
Provide an electrolyte for a lithium secondary battery that can form a lithium battery that is excellent in battery cycle characteristics under severe conditions and also has excellent battery characteristics such as storage characteristics, and a lithium secondary battery using the same. For this purpose, an electrolyte for a lithium secondary battery characterized by including an alkyne derivative and an alkoxybenzene derivative in a non-aqueous electrolyte, and a lithium secondary battery using the same have been found. The present invention provides a lithium secondary battery including a positive electrode, a negative electrode, and a nonaqueous electrolyte in which an electrolyte is dissolved in a nonaqueous solvent, wherein the positive electrode is a material containing a lithium composite oxide, and the negative electrode is a material containing graphite. The non-aqueous solvent contains a cyclic carbonate and a chain carbonate as main components, and is contained in the non-aqueous electrolyte solution by the following general formula (I):
(II)

[0012]

Embedded image

[0013]

Embedded image

(Wherein R ¹ and R ² each independently represent a methyl group or an ethyl group, m represents the number of substituents of 1 to 3. However, when m = 2 or 3, R ² represents Each independently represents a methyl group or an ethyl group, and n is an integer of 1 or 2.) in an amount of 0.001 to 0.8% by weight, and the following general formula (I)
II), (IV), (V), (VI)

[0015]

Embedded image

[0016]

Embedded image

[0017]

Embedded image

[0018]

Embedded image

(Wherein, R ^{3 to} R ¹⁹ each independently represent an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, an aryl group, or a hydrogen atom.
R ⁴ and R ^5, R ⁶ and R ^7, R ⁸ and R ^9, R ¹⁰ and R ^11, R ¹² and R
¹³ , R ¹⁵ and R ¹⁶ , and R ¹⁷ and R ¹⁸ may be bonded to each other to form a cycloalkyl group having 3 to 6 carbon atoms. Wherein Y ¹ is —COOR ²⁰ , —COR ²⁰ or —SO ₂ R
^20, Y ² is, -COOR ^{2 1,} -COR ²¹ or -SO ₂ R
²¹ , Y ³ is -COOR ²² , -COR ²² or -SO ₂ R
²² , Y ⁴ is —COOR ²³ , —COR ²³ or —SO ₂ R
²³ and Y ⁵ are -COOR ²⁴ , -COR ²⁴ or-
Shows the SO ₂ R ^24, wherein ^{R 20, R 21, R 22} , R 23 and R ²⁴ are each independently an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, an aryl group Is shown. Here, x represents an integer of 1 or 2. The present invention relates to a lithium secondary battery containing the alkyne derivative represented by the formula (1) in an amount of 0.1 to 10% by weight.

The present invention also relates to a non-aqueous electrolyte for a lithium secondary battery comprising a positive electrode made of a material containing a lithium composite oxide and a negative electrode made of a material containing graphite, wherein the non-aqueous electrolyte is a non-aqueous solvent. A non-aqueous electrolyte in which an electrolyte is dissolved, wherein the non-aqueous solvent is mainly composed of a cyclic carbonate and a chain carbonate, and the non-aqueous electrolyte contains the general formula (I) or (II)

[0021]

Embedded image

[0022]

Embedded image

(Wherein, R ¹ and R ² each independently represent a methyl group or an ethyl group, m represents the number of substituents of 1 to 3. However, when m = 2 or 3, R ² represents Each independently represents a methyl group or an ethyl group, and n is an integer of 1 or 2.) in an amount of 0.001 to 0.8% by weight, and the following general formula (I)
II), (IV), (V), (VI)

[0024]

Embedded image

[0025]

Embedded image

[0026]

Embedded image

[0027]

Embedded image

(Wherein, R ^{3 to} R ¹⁹ each independently represent an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, an aryl group, or a hydrogen atom.
R ⁴ and R ^5, R ⁶ and R ^7, R ⁸ and R ^9, R ¹⁰ and R ^11, R ¹² and R
¹³ , R ¹⁵ and R ¹⁶ , and R ¹⁷ and R ¹⁸ may be bonded to each other to form a cycloalkyl group having 3 to 6 carbon atoms. Wherein Y ¹ is —COOR ²⁰ , —COR ²⁰ or —SO ₂ R
^20, Y ² is, -COOR ^{2 1,} -COR ²¹ or -SO ₂ R
²¹ , Y ³ is -COOR ²² , -COR ²² or -SO ₂ R
²² , Y ⁴ is —COOR ²³ , —COR ²³ or —SO ₂ R
²³ and Y ⁵ are -COOR ²⁴ , -COR ²⁴ or-
Shows the SO ₂ R ^24, wherein ^{R 20, R 21, R 22} , R 23 and R ²⁴ are each independently an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, an aryl group Is shown. Here, x represents an integer of 1 or 2. The present invention relates to a non-aqueous electrolyte for a lithium secondary battery, which comprises 0.1 to 10% by weight of an alkyne derivative represented by the formula (1).

In the present invention, by adding a very small amount of the above-mentioned alkoxybenzene derivative contained in the electrolytic solution of 0.08% by weight or less, a minute overvoltage portion where the potential of the surface of the positive electrode material excessively increases during charging is obtained. It is presumed that the alkoxybenzene derivative preferentially undergoes oxidative decomposition before the non-aqueous solvent electrolyte in the battery, thereby preventing oxidative decomposition of the solvent. In this way, it is considered to have an effect of suppressing the decomposition of the electrolyte solution without impairing the normal reaction of the battery.

Further, the alkyne derivative contained in the electrolyte of the present invention is preferentially reduced and decomposed prior to the non-aqueous solvent electrolyte when lithium ions are intercalated, and It is presumed that reductive decomposition of the non-aqueous solvent electrolyte in the solution is prevented. Thus, it is considered that the active and highly crystallized carbon material such as natural graphite or artificial graphite is coated with the passivation film, and has an effect of suppressing the decomposition of the electrolytic solution without impairing the normal reaction of the battery. .

In the non-aqueous electrolyte secondary battery comprising a positive electrode, a negative electrode, and a non-aqueous electrolyte solvent containing a lithium salt according to the present invention, when either one of the alkoxybenzene derivative and the alkyne derivative does not exist, charging is performed. At times, the electrolyte is partially oxidized or reductively decomposed on the surface of the positive or negative electrode material, and the battery characteristics cannot be said to be sufficiently satisfactory. By including both the alkoxybenzene derivative and the alkyne derivative in the battery, the cycle characteristics and electric capacity in a wide temperature range can be further improved as compared with the case where the alkoxybenzene derivative or the alkyne derivative is used alone. A lithium secondary battery having excellent battery characteristics such as storage characteristics can be provided.

[0032]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The non-aqueous electrolyte of the present invention is used as a component of a lithium secondary battery. The constituent members other than the non-aqueous electrolyte constituting the secondary battery are not particularly limited, and various constituent members conventionally used can be used.

In the alkoxybenzene derivatives represented by the general formulas (I) and (II) contained in the electrolytic solution in which the electrolyte is dissolved in a non-aqueous solvent, R ¹ and R ² each independently represent a methyl group And an ethyl group. Also, m is preferably 1 to 3 substituents. However, when m = 2 or 3, each R ² independently represents a methyl group or an ethyl group. For example, all may be the same as only a methyl group or an ethyl group, or may be different substituents such as a methyl group and an ethyl group.

The alkoxy group represented by the above general formula (I)
Specific examples of the benzene derivative include, for example, 1,2-dimethyl
Toxibenzene [R¹= R^Two= Methyl group, m = 1], 1,
3-dimethoxybenzene [R¹= R^Two= Methyl group, m =
1], 1,4-dimethoxybenzene [R¹= R^Two= Methyl
Group, m = 1], 1,2,3-trimethoxybenzene [R
¹= Methyl group, R^Two= All methyl groups, m = 2], 1, 2,
4-trimethoxybenzene [R¹= Methyl group, R^Two= All
Methyl group, m = 2], 1,3,5-trimethoxybenze
[R¹= Methyl group, R^Two= All methyl groups, m = 2],
1,2,3,4-tetramethoxybenzene [R¹= Met
R group, R^Two= All methyl groups, m = 3], 1,2,4,5
-Tetramethoxybenzene [R¹= Methyl group, R^Two= All
Methyl group, m = 3], 1,3,4,5-tetramethoxy
Benzene [R¹= Methyl group, R^Two= All methyl groups, m =
3], 1,2-diethoxybenzene [R¹= R^Two= Ethyl
Group, m = 1], 1,3-diethoxybenzene [R¹= R^Two
= Ethyl group, m = 1], 1,4-diethoxybenzene
[R¹= R^Two= Ethyl group, m = 1], 1,2,3-trie
Toxibenzene [R¹= Ethyl group, R^Two= All ethyl groups,
m = 2], 1,2,4-triethoxybenzene [R¹=
Ethyl group, R^Two= All ethyl groups, m = 2], 1, 3, 5
-Triethoxybenzene [R¹= Ethyl group, R^Two= All d
Tyl group, m = 2], 1,2,3,4-tetraethoxybe
Nsen [R¹= Ethyl group, R^Two= All ethyl groups, m =
3], 1,2,4,5-tetraethoxybenzene [R¹
= Ethyl group, R^Two= All ethyl groups, m = 3], 1,3
4,5-tetraethoxybenzene [R¹= Ethyl group, R^Two
= All ethyl groups, m = 3], 2-ethoxyanisole
[R¹= Methyl group, R ^Two= Ethyl group, m = 1], 4-ethoxy
Xyanisole [R¹= Methyl group, R^Two= Ethyl group, n =
1], 1-ethoxy-3,4-dimethoxybenzene [R
¹= Ethyl group, R^Two= All methyl groups, m = 2], 1-eth
Xy-2,6-dimethoxybenzene [R¹= Ethyl group,
R^Two= All methyl groups, m = 2], 1,4-diethoxy-
2-methoxybenzene [R¹= Methyl group, R^Two= All
Group, m = 2], 2,5-diethoxy-1,3-dimethoate
Xybenzene [R¹= Methyl group, R^Two= Ethyl group at position 2,
A methyl group at the 3-position, an ethyl group at the 5-position, and m = 3].
Can be

Specific examples of the alkoxybenzene derivative represented by the general formula (II) include 1,2-methylenedioxybenzene [n = 1] and 1,2-ethylenedioxybenzene [n = 2]. No.

If the content of the alkoxybenzene derivative represented by the general formulas (I) and (II) contained in the non-aqueous electrolyte is excessively high, the upper limit voltage is higher than 4.1 V and / or Battery performance deteriorates in charge and discharge in a high temperature state of 40 ° C. or higher. In addition, sufficient battery performance expected to be excessively small cannot be obtained. Therefore, the content thereof is preferably in the range of 0.001 to 0.8% by weight, more preferably 0.01 to 0.5% by weight, and most preferably 0.03 to 0.8% by weight based on the weight of the nonaqueous electrolyte. The range of 0.3% by weight is good because the cycle characteristics are improved.

The alkoxybenzene derivative of the present invention is used in 0.
The electrolytic solution containing 001 to 0.8% by weight is compared with an electrolytic solution containing no alkoxybenzene derivative or an electrolytic solution containing more than 0.8% by weight of alkoxybenzene.
It has been found that in charge / discharge at an upper limit voltage higher than 4.1 V and / or at a high temperature of 40 ° C. or higher, a unique and unexpected effect of dramatically improving cycle characteristics is exhibited. This mechanism of action is considered to be due to the fact that the additive is oxidatively decomposed on the positive electrode at the time of charging to form a thin polymer film having a high molecular weight, although this does not deviate from the speculation range. That is, if an amount exceeding 0.8% by weight is added, the amount of the additive which is oxidatively decomposed on the positive electrode during charging increases, and a thick polymer film which impairs battery characteristics is formed. It is considered that battery characteristics such as cycle characteristics are deteriorated as compared with the electrolytic solution not added. As described above, it has been found that the addition of 0.001 to 0.8% by weight of the additive of the present invention has the effect of significantly improving the cycle characteristics, leading to the present invention.

The above-mentioned general formulas (III), (IV) contained in the electrolytic solution in which the electrolyte is dissolved in a non-aqueous solvent,
In the alkyne derivatives represented by (V) and (VI),
R ^{3 to} R ¹⁹ each independently represent a methyl group, an ethyl group,
An alkyl group having 1 to 12 carbon atoms such as a propyl group, a butyl group, a pentyl group and a hexyl group is preferred. The alkyl group may be a branched alkyl group such as an isopropyl group and an isobutyl group. Further, a cycloalkyl group having 3 to 6 carbon atoms such as a cyclopropyl group and a cyclohexyl group may be used.
Further, those containing an aryl group having 6 to 12 carbon atoms such as a phenyl group, a benzyl group and a p-tolyl group may be used.
Further, it may be a hydrogen atom. R ⁴ and R ⁵ , R ⁶ and R ⁷ , R ⁸ and R ⁹ , R ¹⁰ and R ¹¹ , R ¹² and R ¹³ , R ¹⁵ and R ¹⁶ , R ¹⁷ and R ¹⁸ , each having 2 to 5 May form a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, or a cyclohexyl group linked by a methylene chain of Here, x represents an integer of 1 or 2.

Alkyne represented by the general formula (III)
As a specific example of the derivative, for example, Y ¹= -COOR²⁰of
In this case, 2-propynylmethyl carbonate [R^Three= R^Four=
R^Five= Hydrogen atom, R²⁰= Methyl group, x = 1], 1-methyl
2-propynylmethyl carbonate [R^Three= Hydrogen source
Child, R^Four= Methyl group, R^Five= Hydrogen atom, R²⁰= Methyl group,
x = 1], 2-propynylethyl carbonate [R^Three=
R^Four= R^Five= Hydrogen atom, R^{Two 0}= Ethyl group, x = 1], 2-
Propinyl propyl carbonate [R^Three= R^Four= R^Five= Water
Elemental atom, R²⁰= Propyl group, x = 1], 2-propynyl
Butyl carbonate [R^Three= R^Four= R^Five= Hydrogen atom, R²⁰
= Butyl group, x = 1], 2-propynylphenylcarbo
Nate [R^Three= R^Four= R^Five= Hydrogen atom, R²⁰= Phenyl
Group, x = 1], 2-propynylcycliclehexylcarbonate
[R^Three= R^Four= R^Five= Hydrogen atom, R²⁰= Cyclohexyl
Group, x = 1], 2-butynylmethyl carbonate [R
^Three= Methyl group, R^Four= R^Five= Hydrogen atom, R²⁰= Methyl group,
x = 1], 3-butynylmethyl carbonate [R^Three= R^Four
= R^Five= Hydrogen atom, R²⁰= Methyl group, x = 2], 2-pe
Nthinyl methyl carbonate [R^Three= Ethyl group, R^Four= R
^Five= Hydrogen atom, R²⁰= Methyl group, x = 1], 1-methyl
-2-butynylmethyl carbonate [R^Three= R^Four= Methyl
Group, R^Five= Hydrogen atom, R²⁰= Methyl group, x = 1], 1,
1-dimethyl-2-propynylmethyl carbonate [R
^Three= Hydrogen atom, R^Four= R^Five= Methyl group, R²⁰= Methyl group,
x = 1], 1,1-diethyl-2-propynylmethylca
-Bonate [R^Three= Hydrogen atom, R^Four= R^Five= Ethyl group, R
²⁰= Methyl group, x = 1], 1,1-ethylmethyl-2-
Propinyl methyl carbonate [R^Three= Hydrogen atom, R^Four=
Ethyl group, R^Five= Methyl group, R²⁰= Methyl group, x =
1], 1,1-isobutylmethyl-2-propynylmethyl
Leucarbonate [R^Three= Hydrogen atom, R^Four= Isobutyl group,
R^Five= Methyl group, R²⁰= Methyl group, x = 1], 1,1-
Dimethyl-2-butynylmethyl carbonate [R^Three= R^Four
= R^Five= Methyl group, R²⁰= Methyl group, x = 1], 1-d
Tinylcyclohexylmethyl carbonate [R^Three= Hydrogen
Atom, R^FourAnd R^FiveIs a pentamethylene group, R²⁰= Met
Group, x = 1], 1,1-phenylmethyl-2-prop
Nylmethyl carbonate [R^Three= Hydrogen atom, R^Four= Pheni
R group, R^Five= Methyl group, R²⁰= Methyl group, x = 1],
1,1-diphenyl-2-propynylmethyl carbonate
G [R^Three= Hydrogen atom, R^Four= R^Five= Phenyl group, R²⁰= Me
Tyl group, x = 1], 1,1-dimethyl-2-propynyl
Ethyl carbonate [R^Three= Hydrogen atom, R^Four= R^Five= Met
R group, R²⁰= Ethyl group, x = 1] and the like. Y
¹= -COR²⁰In the case of 2-propynyl acetate [R^Three= R^Four
= R^Five= Hydrogen atom, R²⁰= Methyl group, x = 1], acetic acid 1
-Methyl-2-propynyl [R^Three= Hydrogen atom, R^Four= Met
R group, R^Five= Hydrogen atom, R²⁰= Methyl group, x = 1],
2-propynyl ropionate [R^Three= R^Four= R^Five= Hydrogen source
Child, R²⁰= Ethyl group, x = 1], 2-propynyl butyrate
[R^Three= R^Four= R^Five= Hydrogen atom, R²⁰= Propyl group, x =
1], 2-propynyl benzoate [R^Three= R^Four= R^Five= Hydrogen
Atom, R²⁰= Phenyl group, x = 1], cyclohexylca
2-propynyl rubonate [R^Three= R^Four= R^Five= Hydrogen atom,
R²⁰= Cyclohexyl group, x = 1], 2-butynyl acetate
[R^Three= Methyl group, R^Four= R^Five= Hydrogen atom, R²⁰= Methyl
Group, x = 1], 3-butynyl acetate [R^Three= R^Four= R^Five= Water
Elemental atom, R²⁰= Methyl group, x = 2], 2-pentiniacetic acid
[R^Three= Ethyl group, R^Four= R^Five= Hydrogen atom, R²⁰= Met
Group, x = 1], 1-methyl-2-butynyl acetate [R^Three
= R^Four= Methyl group, R^Five= Hydrogen atom, R²⁰= Methyl group, x
= 1], 1,1-dimethyl-2-propynyl acetate [R^Three
= Hydrogen atom, R^Four= R^Five= Methyl group, R²⁰= Methyl group, x
= 1], 1,1-diethyl-2-propynyl acetate [R^Three
= Hydrogen atom, R^Four= R^Five= Ethyl group, R²⁰= Methyl group, x
= 1], 1,1-ethylmethyl-2-propynyl acetate
[R^Three= Hydrogen atom, R^Four= Ethyl group, R^Five= Methyl group, R
²⁰= Methyl group, x = 1], 1,1-isobutylmethyl acetate
Ru-2-propynyl [R^Three= Hydrogen atom, R^Four= Isobutyl
Group, R^Five= Methyl group, R²⁰= Methyl group, x = 1], acetic acid
1,1-dimethyl-2-butynyl [R^Three= R^Four= R^Five= Me
Tyl group, R²⁰= Methyl group, x = 1], 1-ethynyl acetate
Cyclohexyl [R^Three= Hydrogen atom, R^FourAnd R^FiveIs a bond =
Tamethylene group, R²⁰= Methyl group, x = 1], acetic acid 1,
1-phenylmethyl-2-propynyl [R^Three= Hydrogen source
Child, R^Four= Phenyl group, R^Five= Methyl group, R²⁰= Methyl
Group, x = 1], 1,1-diphenyl-2-propynyl acetate
[R^Three= Hydrogen atom, R^Four= R^Five= Phenyl group, R²⁰= Me
Tyl group, x = 1], 1,1-dimethyl-2 propionate
-Propynyl [R^Three= Hydrogen atom, R^Four= R^Five= Methyl group,
R²⁰= Ethyl group, x = 1] and the like. Y¹= −
SO_TwoR²⁰In the case of 2-propynyl methanesulfonate
[R^Three= R^Four= R^Five= Hydrogen atom, R²⁰= Methyl group, x =
1], 1-methyl-2-propynyl methanesulfonate
[R^Three= Hydrogen atom, R^Four= Methyl group, R^Five= Hydrogen atom, R
²⁰= Methyl group, x = 1], 2-propaneethanesulfonic acid
Nil [R^Three= R^Four= R^Five= Hydrogen atom, R²⁰= Ethyl group, x
= 1], 2-propynyl propanesulfonate [R^Three= R^Four
= R^Five= Hydrogen atom, R²⁰= Propyl group, x = 1], p-
2-propynyl toluenesulfonic acid [R^Three= R^Four= R^Five=
Hydrogen atom, R²⁰= P-tolyl group, x = 1], cyclohexyl
2-propynyl silsulfonate [R^Three= R^Four= R^Five= Hydrogen
Atom, R²⁰= Cyclohexyl group, x = 1], methanesulfur
2-butynyl phonate [R^Three= Methyl group, R^Four= R^Five= Hydrogen
Atom, R²⁰= Methyl group, x = 1], methanesulfonic acid 3
-Butynyl [R^Three= R^Four= R^Five= Hydrogen atom, R²⁰= Methyl
Group, x = 2], 2-pentynyl methanesulfonate [R^Three
= Ethyl group, R^Four= R^Five= Hydrogen atom, R²⁰= Methyl group, x
= 1], 1-methyl-2-butynyl methanesulfonate
[R^Three= R^Four= Methyl group, R^Five= Hydrogen atom, R²⁰= Methyl
Group, x = 1], 1,1-dimethyl-2 methanesulfonate
-Propynyl [R^Three= Hydrogen atom, R^Four= R^Five= Methyl group,
R²⁰= Methyl group, x = 1], methanesulfonic acid 1,1-
Diethyl-2-propynyl [R^Three= Hydrogen atom, R^Four= R^Five
= Ethyl group, R²⁰= Methyl group, x = 1], methanesulfo
1,1-ethylmethyl-2-propynyl acid [R^Three= Water
Elemental atom, R^Four= Ethyl group, R^Five= Methyl group, R²⁰= Methyl
Group, x = 1], 1,1-isobutylmethanemethanesulfonate
Tyl-2-propynyl [R^Three= Hydrogen atom, R^Four= Isobuti
R group, R^Five= Methyl group, R²⁰= Methyl group, x = 1],
1,1-dimethyl-2-butynyl tansulfonate [R^Three
= R^Four= R^Five= Methyl group, R²⁰= Methyl group, x = 1],
1-ethynylcyclohexyl tansulfonate [R^Three= Water
Elemental atom, R^FourAnd R^FiveIs a pentamethylene group, R²⁰= Me
Tyl group, x = 1], 1,1-phenyl methanesulfonate
Methyl-2-propynyl [R^Three= Hydrogen atom, R^Four= Pheni
R group, R^Five= Methyl group, R^{Two 0}= Methyl group, x = 1],
1,1-diphenyl-2-propynyl tansulfonate
[R^Three= Hydrogen atom, R^Four= R^Five= Phenyl group, R²⁰= Met
Group, x = 1], ethanesulfonic acid 1,1-dimethyl-
2-propynyl [R^Three= Hydrogen atom, R^Four= R^Five= Methyl
Group, R²⁰= Ethyl group, x = 1] and the like. However
However, the present invention is not limited to these compounds at all.
Absent.

Alkyne derivative represented by the general formula (IV)
As a specific example of the conductor, for example, Y^Two= -COOR^{twenty one}And
And Y^Three= -COOR^{twenty two}In the case of 2-butyne-1,4-di
All dimethyl carbonate [R⁶= R⁷= R⁸= R⁹=
Hydrogen atom, R^{twenty one}= R^{twenty two}= Methyl group, x = 1], 2-butyl
1,4-diol diethyl carbonate [R⁶= R
⁷= R⁸= R⁹= Hydrogen atom, R^{twenty one}= R^{twenty two}= Ethyl group, x =
1], 3-hexyne-2,5-diol dimethyldica
-Bonate [R⁶= R⁸= Methyl group, R⁷= R⁹= Hydrogen source
Child, R^{twenty one}= R^{twenty two}= Methyl group, x = 1], 3-hexyne-
2,5-diol diethyl dicarbonate [R⁶= R⁸=
Methyl group, R⁷= R⁹= Hydrogen atom, R^{twenty one}= R^{twenty two}= Ethyl
Group, x = 1], 2,5-dimethyl-3-hexyne-2,
5-diol dimethyl dicarbonate [R⁶= R⁷= R
⁸= R⁹= Methyl group, R^{twenty one}= R^{twenty two}= Methyl group, x = 1],
2,5-dimethyl-3-hexyne-2,5-diol
Diethyl dicarbonate [R⁶= R⁷= R⁸= R⁹= Methyl
Group, R^{twenty one}= R^{twenty two}= Ethyl group, x = 1], etc.
You. Y^Two= -COR^{twenty one}And Y^Three= -COR^{twenty two}In the case of 2,
-Butyne-1,4-diol diacetate [R⁶= R⁷
= R⁸= R⁹= Hydrogen atom, R^{twenty one}= R^{twenty two}= Methyl group, x =
1], 2-butyne-1,4-diol diacetate
[R⁶= R⁷= R⁸= R⁹= Hydrogen atom, R^{twenty one}= R^{twenty two}= Methyl
Group, x = 1], 2-butyne-1,4-diol dipro
Pionate [R⁶= R⁷= R⁸= R⁹= Hydrogen atom, R^{twenty one}= R
^{twenty two}= Ethyl group, x = 1], 3-hexyne-2,5-dio
Diacetate [R⁶= R⁸= Methyl group, R⁷= R⁹=
Hydrogen atom, R^{twenty one}= R^{twenty two}= Methyl group, x = 1], 3-hexyl
Syn-2,5-diol dipropionate [R⁶= R⁸
= Methyl group, R⁷= R⁹= Hydrogen atom, R^{twenty one}= R^{twenty two}= Ethyl
Group, x = 1], 2,5-dimethyl-3-hexyne-2,
5-diol diacetate [R⁶= R⁷= R⁸= R⁹= Me
Tyl group, R^{twenty one}= R^{twenty two}= Methyl group, x = 1], 2,5-di
Methyl-3-hexyne-2,5-diol dipropio
Nate [R⁶= R⁷= R⁸= R⁹= Methyl group, R¹²¹= R^{twenty two}
= Ethyl group, x = 1] and the like. Y^Two= -SO_Two
R^{twenty one}And Y^Three= -SO_TwoR^{twenty two}In the case of 2-butyne-1,
4-diol dimethanesulfonate [R⁶= R⁷= R⁸=
R⁹= Hydrogen atom, R^{twenty one}= R^{twenty two}= Methyl group, x = 1], 2
-Butyne-1,4-diol diethanesulfonate
[R⁶= R⁷= R⁸= R⁹= Hydrogen atom, R^{Two 1}= R^{twenty two}= Ethyl
Group, x = 1], 3-hexyne-2,5-diol
Tansulfonate [R⁶= R⁸= Methyl group, R⁷= R⁹= Water
Elemental atom, R^{twenty one}= R^{twenty two}= Methyl group, x = 1], 3-hexyl
-2,5-diol diethanesulfonate [R⁶=
R⁸= Methyl group, R⁷= R⁹= Hydrogen atom, R^{twenty one}= R^{twenty two}= D
Tyl group, x = 1], 2,5-dimethyl-3-hexyne-
2,5-diol dimethanesulfonate [R⁶= R⁷=
R⁸= R⁹= Methyl group, R^{twenty one}= R^{twenty two}= Methyl group, x =
1], 2,5-dimethyl-3-hexyne-2,5-dio
Diethanesulfonate [R⁶= R⁷= R ⁸= R⁹= Me
Tyl group, R^{twenty one}= R^{twenty two}= Ethyl group, x = 1], etc.
It is. However, the present invention is not limited to these compounds.
Not something.

Alkyne derivative represented by the above general formula (V)
As a specific example of the body, for example, Y^Four= -COOR^{twenty three}and
Y^Five= -COOR^{twenty four}In the case of 2,4-hexadiyne-
1,6-diol dimethyl dicarbonate [R^Ten= R
¹¹= R¹²= R¹³= Hydrogen atom, R ^{twenty three}= R^{twenty four}= Methyl group, x
= 1], 2,4-hexadiyne-1,6-diol di
Ethyl dicarbonate [R^Ten= R¹¹= R¹²= R¹³= Hydrogen
Atom, R^{twenty three}= R^{twenty four}= Ethyl group, x = 1], 2,7-dimethyl
Cyl-3,5-octadiyne-2,7-diol dimethyl
Lujicarbonate [R^Ten= R¹¹= R¹²= R¹³= Methyl
Group, R^{twenty three}= R^{twenty four}= Methyl group, x = 1], 2,7-dimethyl
-3,5-octadiyne-2,7-diol diethyl
Lujicarbonate [R^Ten= R¹¹= R¹²= R¹³= Methyl
Group, R^{twenty three}= R ^{twenty four}= Ethyl group, x = 1], etc.
You. Y^Four= -COR^{twenty three}And Y^Five= -COR^{twenty four}in the case of,
2,4-hexadiyne-1,6-diol diacetate
G [R^Ten= R¹¹= R¹²= R¹³= Hydrogen atom, R^{twenty three}= R^{twenty four}=
Methyl group, x = 1], 2,4-hexadiyne-1,6-
Diol dipropionate [R^Ten= R¹¹= R¹²= R¹³
= Hydrogen atom, R^{twenty three}= R^{twenty four}= Ethyl group, x = 1], 2,7
-Dimethyl-3,5-octadiyne-2,7-diol
 Diacetate [R^Ten= R¹¹= R¹²= R¹³= Methyl group,
R^{twenty three}= R^{twenty four}= Methyl group, x = 1], 2,7-dimethyl-
3,5-octadiyne-2,7-diol dipropio
Nate [R^Ten= R¹¹= R¹²= R¹³= Methyl group, R^{twenty three}= R
^{twenty four}= Ethyl group, x = 1] and the like. Y^Four= -S
O_TwoR^{twenty three}And Y ^Five= -SO_TwoR^{twenty four}In the case of 2,4-hex
Sadiin-1,6-diol dimethanesulfonate
[R^Ten= R¹¹= R¹²= R¹³= Hydrogen atom, R^{twenty three}= R^{twenty four}= Me
Tyl group, x = 1], 2,4-hexadiyne-1,6-di
All ethanesulfonate [R^Ten= R¹¹= R¹²= R
¹³= Hydrogen atom, R^{twenty three}= R^{twenty four}= Ethyl group, x = 1], 2,
7-dimethyl-3,5-octadiyne-2,7-dio
Dimethanesulfonate [R ^Ten= R¹¹= R¹²= R¹³=
Methyl group, R^{twenty three}= R^{twenty four}= Methyl group, x = 1], 2,7-
Dimethyl-3,5-octadiyne-2,7-diol
Diethane sulfonate [R^Ten= R¹¹= R¹²= R¹³= Met
R group, R^{twenty three}= R^{twenty four}= Ethyl group, x = 1], etc.
You. However, the present invention is not limited to these compounds.
Not something.

Alkyne derivative represented by the above general formula (VI)
Specific examples of the conductor include, for example, dipropargyl carb
Nate [R¹⁴= R^Fifteen= R¹⁶= R¹⁷= R¹⁸= R¹⁹= Hydrogen source
, X = 1], di (1-methyl-2-propynyl) car
Bonate [R¹⁴= R¹⁶= R¹⁸= R¹⁹= Hydrogen atom, R^Fifteen=
R¹⁷= Methyl group, x = 1], di (2-butynyl) carbo
Nate [R¹⁴= R¹⁹= Methyl group, R^Fifteen= R¹⁶= R¹⁷= R
¹⁸= Hydrogen atom, x = 1], di (3-butynyl) carbonate
[R¹⁴= R^Fifteen= R¹⁶= R¹⁷= R¹⁸= R¹⁹= Hydrogen source
, X = 2], di (2-pentynyl) carbonate [R
¹⁴= R¹⁹= Ethyl group, R^Fifteen= R¹⁶= R¹⁷= R¹⁸= Hydrogen source
, X = 1], di (1-methyl-2-butynyl) carbo
Nate [R¹⁴= R^Fifteen= R¹⁶= R¹⁹= Methyl group, R¹⁷= R
¹⁸= Hydrogen atom, x = 1], 2-propynyl 2-butini
Leucarbonate [R¹⁴= R^Fifteen= R¹⁶= R¹⁷= R¹⁸= Hydrogen
Atom, R¹⁹= Methyl group, x = 1], di (1,1-dimethyl)
Ru-2-propynyl) carbonate [R¹⁴= R¹⁹= Hydrogen
Atom, R^Fifteen= R¹⁶= R¹⁷= R ¹⁸= Methyl group, x = 1],
Di (1,1-diethyl-2-propynyl) carbonate
[R¹⁴= R¹⁹= Hydrogen atom, R^Fifteen= R¹⁶= R¹⁷= R¹⁸= D
Tyl group, x = 1], di (1,1-ethylmethyl-2-propyl)
Ropinyl) carbonate [R¹⁴= R¹⁹= Hydrogen atom, R^Fifteen
= R¹⁷= Ethyl group, R¹⁶= R¹⁸= Methyl group, x = 1],
Di (1,1-isobutylmethyl-2-propynyl) car
Bonate [R¹⁴= R¹⁹= Hydrogen atom, R^Fifteen= R¹⁷= Isobu
Tyl group, R¹⁶= R¹⁸= Methyl group, x = 1], di (1,1
-Dimethyl-2-butynyl) carbonate [R¹⁴= R^Fifteen
= R¹⁶= R¹⁷= R¹⁸= R¹⁹= Methyl group, x = 1], di
(1-ethynylcyclohexyl) carbonate [R¹⁴=
R¹⁹= Hydrogen atom, R^FifteenAnd R¹⁶Is a bond = pentamethylene
Group, R¹⁷And R¹⁸Is a bond = pentamethylene group, n = 1] is
No. However, the present invention is not limited to these compounds.
It is not specified.

In the alkyne derivatives, if the content of the alkyne derivatives represented by the general formulas (III), (IV), (V), and (VI) is excessively large, the conductivity of the electrolytic solution and the like may be reduced. Alternately, the battery performance may be reduced, and if the amount is excessively small, a sufficient film is not formed and the expected battery characteristics cannot be obtained. Particularly, a range of 0.5 to 5% by weight is preferable.

The non-aqueous solvent used in the present invention is preferably a solvent mainly composed of a cyclic carbonate and a chain carbonate. Preferred examples of the cyclic carbonate include cyclic carbonates such as ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), and vinylene carbonate (VC). These high dielectric constant solvents may be used alone or in combination of two or more.

Examples of the chain carbonate include dimethyl carbonate (DMC) and ethyl methyl carbonate (EM
Chain carbonates such as C) and diethyl carbonate (DEC) are preferred. These high dielectric constant solvents may be used alone or in combination of two or more. It is preferable that the content of the cyclic carbonate in the non-aqueous solvent is 10% by weight or more and 70% by weight or less, and the content of the chain carbonate is 30% by weight or more and 90% by weight or less. Furthermore, a low-viscosity solvent can be contained. Specific examples of the low-viscosity solvent include, for example, tetrahydrofuran, 2-methyltetrahydrofuran, 1,4-dioxane, 1,2-dimethoxyethane,
Ethers such as 1,2-diethoxyethane and 1,2-dibutoxyethane, lactones such as γ-butyrolactone, nitriles such as acetonitrile, methyl propionate, methyl pivalate, ethyl pivalate, octyl pivalate and the like Esters, amides such as dimethylformamide, triethyl phosphate, tributyl phosphate,
And phosphate esters such as trioctyl phosphate. These low-viscosity solvents may be used alone or in combination of two or more.

As the electrolyte used in the present invention, for example, LiPF ₆ , LiBF ₄ , LiAsF ₆ , LiCl
O ₄ , LiN (SO ₂ CF ₃ ) ₂ , LiN (SO ₂ C
_{2 F 5) 2, LiC (} SO 2 CF 3) 3, LiPF 4 (CF 3)
₂ , LiPF ₃ (C ₂ F ₅ ) ₃ , LiPF ₃ (CF ₃ ) ₃ , Li
PF ₃ (iso-C ₃ F ₇ ) ₃ , LiPF ₅ (iso-C ₃ F)
₇ ). These electrolytes may be used alone or in combination of two or more. These electrolytes are usually added to the non-aqueous solvent at 0.1 to 3
M, preferably dissolved at a concentration of 0.5 to 1.5M.

The non-aqueous electrolyte of the present invention is prepared, for example, by mixing a high dielectric constant solvent and a low-viscosity solvent, dissolving the above-mentioned electrolyte therein, and forming an alkoxybenzene derivative represented by the above formula (I) or (II). And the formulas (III), (IV), (V),
It is obtained by dissolving the alkyne derivative represented by (VI).

For example, as the positive electrode active material, a composite metal oxide of lithium and at least one metal selected from the group consisting of cobalt, manganese, nickel, chromium, iron and vanadium is used. Examples of such a composite metal oxide include LiCoO ₂ , LiMn ₂ O ₄ ,
LiNiO _{2 and the} like.

For the positive electrode, a conductive agent such as acetylene black or carbon black, polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), a copolymer of styrene and butadiene (SB)
R), a copolymer of acrylonitrile and butadiene (NB
R), a binder such as carboxymethylcellulose (CMC) and a solvent are kneaded to form a positive electrode mixture, and the positive electrode material is applied to an aluminum foil or a stainless steel lath plate as a current collector, dried, and dried. After pressure molding, 50 ° C ~ 250
It is produced by performing a heat treatment under a vacuum at a temperature of about 2 ° C. for about 2 hours.

As the negative electrode active material, a material containing graphite having a graphite type crystal structure capable of inserting and extracting lithium, such as natural graphite and artificial graphite, is used. In particular, the plane interval (d ₀₀₂ ) of the lattice plane ( ₀₀₂ ) is 0.335-0.
It is preferable to use a carbon material having a graphite type crystal structure of 340 nm (nanometer). Note that powder materials such as carbon materials are ethylene propylene diene terpolymer (EPDM) and polytetrafluoroethylene (PTDM).
FE), polyvinylidene fluoride (PVDF), copolymer of styrene and butadiene (SBR), copolymer of acrylonitrile and butadiene (NBR), and kneaded with a binder such as carboxymethylcellulose (CMC) to form a negative electrode mixture. used.

The structure of the lithium secondary battery is not particularly limited. A coin-type battery having a positive electrode, a negative electrode and a single-layer or multi-layer separator, and a cylindrical battery having a positive electrode, a negative electrode and a roll-shaped separator And a prismatic battery. As the separator, a known microporous polyolefin membrane, woven fabric, nonwoven fabric, or the like is used.

The voltage range of the charge / discharge cycle of the lithium secondary battery according to the present invention is preferably such that the maximum operating voltage is higher than 4.1 V, more preferably higher than 4.2 V, and most preferably higher than 4.3 V. . The cutoff voltage is preferably 2.0 V or more, more preferably 2.5 V
V or more. Although the current value is not particularly limited, it is usually used at a constant current discharge of 0.1 to 2C. The temperature range of the charge / discharge cycle is preferably −40 to 100 ° C., and more preferably 40 to 80 ° C.

[0053]

Next, the present invention will be specifically described with reference to examples and comparative examples. Example 1 [Preparation of non-aqueous electrolyte] PC: DMC (volume ratio) = 1: 2
Was prepared and a non-aqueous electrolyte was prepared by dissolving LiPF ₆ to a concentration of 1 M in the non-aqueous solvent, and then 1,2,4-trimethoxybenzene [ In the formula (I), R ¹ = methyl group, R ² = all methyl group, m
= 2] and 0.1% by weight of 2-propynyl methanesulfonate [in the formula (III), Y ¹ = -SO ₂ R ²⁰ , R ³ =
R ⁴ = R ⁵ = hydrogen atom, R ²⁰ = methyl group, x = 1].
0% by weight was added.

[Production of Lithium Secondary Battery and Measurement of Battery Characteristics] LiCoO ₂ (cathode active material) was 80% by weight, acetylene black (conductive agent) was 10% by weight, and polyvinylidene fluoride (binder) was 10% by weight. % Of the mixture, a 1-methyl-2-pyrrolidone solvent was added to the mixture, and the mixture was applied onto an aluminum foil, dried, press-molded, and heat-treated to prepare a positive electrode. 90% by weight of natural graphite (negative electrode active material) and 10% by weight of polyvinylidene fluoride (binder) were added, and a 1-methyl-2-pyrrolidone solvent was added thereto. Applied, dried,
A negative electrode was prepared by pressure molding and heat treatment. Then, using a separator made of a polypropylene microporous film, the above non-aqueous electrolyte was injected, and a coin battery (20 mm in diameter,
(Thickness: 3.2 mm). Using this coin battery, 4.3 V at a constant current of 0.8 mA under high temperature (40 ° C.)
After charging to a final voltage of 4.3 V, the battery was charged at a constant voltage for a total of 6 hours. Next, the battery was discharged to a final voltage of 2.7 V under a constant current of 0.8 mA, and the charging and discharging were repeated. The initial discharge capacity is 1M LiPF ₆ + EC: PC: DEC
(Capacity ratio) = 1.00 as a relative ratio when the non-aqueous electrolyte solution of 3: 1: 6 (Comparative Example 4; no alkoxybenzene derivative or alkyne derivative added) was set to 1. When the initial discharge capacity was 100%, the discharge capacity retention after 100 cycles was 92.5%. Also, the low-temperature characteristics were good. Table 1 shows the manufacturing conditions and battery characteristics of the coin battery.

Comparative Example 1 A non-aqueous solvent of PC: DMC (volume ratio) = 1: 2 was prepared.
LiPF ₆ was dissolved therein to a concentration of 1M.
At this time, the alkoxybenzenebenzene derivative and the alkyne derivative were not added at all. Using this non-aqueous electrolyte, a coin battery was fabricated in the same manner as in Example 1, and the battery characteristics were measured. Table 1 shows the manufacturing conditions and battery characteristics of the coin battery.

Comparative Example 2 A non-aqueous electrolyte was prepared in the same manner as in Example 1, except that only 1,2,4-trimethoxybenzene was used as an additive in an amount of 0.1% by weight based on the non-aqueous electrolyte. To make a coin battery. Using this non-aqueous electrolyte, a final voltage of 4.3 V
Battery characteristics were measured in the same manner as in Example 1 except that the battery was charged for an hour, but it was found that charging and discharging were not performed. Table 1 shows the manufacturing conditions and battery characteristics of the coin battery.

Comparative Example 3 A non-aqueous electrolyte was prepared in the same manner as in Example 1 except that only 2-propynyl methanesulfonate was used as an additive in an amount of 2.0% by weight based on the non-aqueous electrolyte. Was prepared. Table 1 shows the manufacturing conditions and battery characteristics of the coin battery.

[0058]

[Table 1]

Example 2 A non-aqueous solvent of EC / PC / DEC (volume ratio) = 3/1/6 was prepared, and LiPF ₆ was dissolved therein to a concentration of 1 M to prepare an electrolyte. 0.05% by weight of 1,2,4-trimethoxybenzene with respect to the non-aqueous electrolyte, and dipropargyl carbonate [formula (VI)
Where R ¹⁴ = R ¹⁵ = R ¹⁶ = R ¹⁷ = R ¹⁸ = R ¹⁹ = hydrogen atom,
x = 1] was used as a 1.0% by weight additive, and a non-aqueous electrolyte was prepared in the same manner as in Example 1 to produce a coin battery. Table 2 shows the manufacturing conditions and battery characteristics of the coin battery.

Examples 3 to 5 A non-aqueous electrolyte was prepared in the same manner as in Example 2 except that the amounts of 1,2,4-trimethoxybenzene and dipropargyl carbonate were changed, to produce coin batteries. . Table 2 shows the manufacturing conditions and battery characteristics of the coin battery.

Comparative Example 4 A non-aqueous electrolyte was prepared in the same manner as in Example 2 except that 1,2,4-trimethoxybenzene and dipropargyl carbonate were not added, to prepare a coin battery. Table 2 shows the manufacturing conditions and battery characteristics of the coin battery.

Comparative Example 5 Instead of 1,2,4-trimethoxybenzene, 1,2-
A non-aqueous electrolyte was prepared in the same manner as in Example 2 except that dimethoxybenzene was added in an amount of 2.5% by weight based on the electrolyte and dipropargyl carbonate was not added, to produce a coin battery. Table 2 shows coin battery fabrication conditions and battery characteristics.
Shown in

Comparative Example 6 A non-aqueous electrolytic solution was prepared in the same manner as in Comparative Example 5 except that the final voltage at the time of charging was 4.1 V, to produce a coin battery. Table 2 shows the manufacturing conditions and battery characteristics of the coin battery.

Comparative Example 7 Instead of 1,2,4-trimethoxybenzene, 1,3,3
A non-aqueous electrolyte was prepared in the same manner as in Example 2 except that 5-trimethoxybenzene was added in an amount of 2.5% by weight with respect to the electrolyte and dipropargyl carbonate was not added, to produce a coin battery. Table 2 shows the manufacturing conditions and battery characteristics of the coin battery.

Comparative Example 8 Instead of 1,2,4-trimethoxybenzene, 1,2-
A non-aqueous electrolyte was prepared in the same manner as in Example 2 except that dimethoxybenzene was added in an amount of 0.1% by weight based on the electrolyte and dipropargyl carbonate was not added, to prepare a coin battery. Table 2 shows coin battery fabrication conditions and battery characteristics.
Shown in

Comparative Example 9 A non-aqueous electrolyte was prepared in the same manner as in Example 2 except that 1.0% by weight of dipropargyl carbonate was added to the electrolyte and 1,2,4-trimethoxybenzene was not added. It was prepared to make a coin battery. Table 2 shows the manufacturing conditions and battery characteristics of the coin battery.

[0067]

[Table 2]

Example 6 A non-aqueous electrolyte was replaced by 1,2-diethoxybenzene instead of 1,2,4-trimethoxybenzene [in the formula (I):
R ¹ = R ² = ethyl group, m = 1] was added at 0.1% by weight,
1,1-dimethyl-2-propynylmethyl carbonate [formula (III)] instead of dipropargyl carbonate
Where Y ¹ = —COOR ²⁰ , R ³ = hydrogen atom, R ⁴ = R ⁵ = methyl group, R ²⁰ = methyl group, x = 1] were added in the same manner as in Example 2 except that 2.0% by weight was added. A non-aqueous electrolyte was prepared to produce a coin battery. Table 3 shows the manufacturing conditions and battery characteristics of the coin battery.

Examples 7 to 11 Table 3 shows alkoxybenzene derivatives and alkyne derivatives.
A non-aqueous electrolyte was prepared in the same manner as in Example 6 except that the description was changed, and a coin battery was manufactured. Table 3 shows the manufacturing conditions and battery characteristics of the coin battery.

Examples 12 to 14 In the same manner as in Example 6, except that artificial graphite was used in place of natural graphite and the alkoxybenzene derivative and alkyne derivative were changed as shown in Table 3 as the negative electrode active material. A water electrolyte was prepared to produce a coin battery. Table 3 shows the manufacturing conditions and battery characteristics of the coin battery.

[0071]

[Table 3]

Example 15 As a positive electrode active material, LiMn ₂ O ₄ was used instead of LiCoO _2.
And artificial graphite instead of natural graphite as the negative electrode active material, 0.1% by weight of 1,2,4-trimethoxybenzene with respect to the non-aqueous electrolyte, and methanesulfonic acid 2- A non-aqueous electrolyte was prepared in the same manner as in Example 2 except that propynyl was used in an amount of 2.0% by weight to produce a coin battery. The initial discharge capacity was 0.85 as a relative ratio when Comparative Example 4 was set to 1. When the battery characteristics after 100 cycles were measured, the discharge capacity retention ratio was 93.9%. Table 4 shows the manufacturing conditions and battery characteristics of the coin battery.

Example 16 and Comparative Examples 10 to 11 Alkoxybenzene derivatives and alkyne derivatives are shown in Table 4.
Except as described, a non-aqueous electrolyte was prepared in the same manner as in Example 15 to prepare a coin battery. Table 4 shows the manufacturing conditions and battery characteristics of the coin battery.

[0074]

[Table 4]

As described above, when the alkoxybenzene derivative of the present invention is added in an amount of 0.001 to 0.8% by weight and the alkyne derivative in an amount of 0.1 to 10% by weight, the upper limit voltage is higher than 4.1 V and / or Alternatively, it was found that the cycle characteristics were clearly excellent in charge and discharge in a high temperature state of 40 ° C. or higher.

The present invention is not limited to the above-described embodiments, and various combinations that can be easily inferred from the gist of the invention are possible. In particular, the combinations of the solvents in the above examples are not limited. Further, while the above embodiments relate to coin batteries, the present invention is also applicable to cylindrical batteries, prismatic batteries, and laminated polymers.

[0077]

According to the present invention, the cycle characteristics of the battery,
A lithium secondary battery having excellent battery characteristics such as electric capacity and storage characteristics can be provided.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Yasuo Matsumori 10-figure 1978 Kogushi, Ube City, Ube-shi, Yamaguchi F-term in the Ube Chemical Plant Ube Chemical Plant 5H029 AJ03 AJ04 AJ05 AK03 AL07 AM03 AM05 AM07 DJ09 EJ11 HJ01 HJ02 HJ13 5H050 AA07 AA08 AA09 BA17 CA07 CA08 CA09 CB08 DA13 EA22 HA01 HA02 HA13

Claims (12)

[Claims] 1. A lithium secondary battery comprising a positive electrode, a negative electrode and a non-aqueous electrolyte in which an electrolyte is dissolved in a non-aqueous solvent, wherein the positive electrode is a material containing a lithium composite oxide, and the negative electrode is a material containing graphite. The non-aqueous solvent contains a cyclic carbonate and a chain carbonate as main components, and is contained in the non-aqueous electrolytic solution by the following general formulas (I) and (II). Embedded image (Wherein, R ¹ and R ² each independently represent a methyl group or an ethyl group, and m represents the number of substituents of 1 to 3, provided that
When m = 2 or 3, each R ² independently represents a methyl group or an ethyl group. n represents an integer of 1 or 2. ) Is 0.00
1 to 0.8% by weight, and the following general formulas (III) and (I
V), (V), (VI) Embedded image Embedded image Embedded image (Wherein, R ^{3 to} R ¹⁹ each independently represent a C 1 to C 1)
2 represents an alkyl group, a cycloalkyl group having 3 to 6 carbon atoms, an aryl group, or a hydrogen atom. Also, R ⁴ and R ⁵ , R
⁶ and R ⁷ , R ⁸ and R ⁹ , R ¹⁰ and R ¹¹ , R ¹² and R ¹³ , R ¹⁵ and R
¹⁶ , R ¹⁷ and R ¹⁸ may combine with each other to form a cycloalkyl group having 3 to 6 carbon atoms. Wherein Y ¹ is −
COOR ²⁰ , —COR ²⁰ or —SO ₂ R ²⁰ , Y ² is —
COOR ^{2 1,} -COR ²¹ or -SO ₂ R ^21, Y ³ is -
COOR ²² , —COR ²² or —SO ₂ R ²² , Y ⁴ is —
COOR ²³ , —COR ²³ or —SO ₂ R ²³ , and Y ⁵
Represents -COOR ²⁴ , -COR ²⁴ or -SO ₂ R ²⁴ , wherein R ²⁰ , R ²¹ , R ²² , R ²³ and R ²⁴ each independently represent an alkyl group having 1 to 12 carbon atoms, Number 3 ~
6 represents a cycloalkyl group or an aryl group. Where x
Represents an integer of 1 or 2. ), Wherein the alkyne derivative is contained in an amount of 0.1 to 10% by weight. 2. The content of the cyclic carbonate in the non-aqueous solvent is 10% by weight or more and 70% by weight or less, and the content of the chain carbonate is 30% by weight or more and 90% by weight or less. Lithium secondary battery. 3. The lithium secondary battery according to claim 1, wherein the cyclic carbonate is at least one selected from ethylene carbonate, propylene carbonate, butylene carbonate, and vinylene carbonate. 4. The lithium secondary battery according to claim 1, wherein the chain carbonate is at least one selected from dimethyl carbonate, diethyl carbonate, and methyl ethyl carbonate. 5. The lithium secondary battery according to claim 1, wherein said graphite is natural graphite or artificial graphite. 6. The lithium secondary battery according to claim 1, wherein the lattice spacing (002) of the graphite lattice plane ( ₀₀₂ ) is 0.335 to 0.340 nm. 7. A non-aqueous electrolyte for a lithium secondary battery including a positive electrode made of a material containing a lithium composite oxide and a negative electrode made of a material containing graphite, wherein the non-aqueous electrolyte has an electrolyte dissolved in a non-aqueous solvent. Wherein the non-aqueous solvent is mainly composed of a cyclic carbonate and a chain carbonate, and is contained in the non-aqueous electrolyte by the general formulas (I) and (II). Embedded image (Wherein, R ¹ and R ² each independently represent a methyl group or an ethyl group, and m represents the number of substituents of 1 to 3, provided that
When m = 2 or 3, each R ² independently represents a methyl group or an ethyl group. n represents an integer of 1 or 2. ) Is 0.00
1 to 0.8% by weight, and the following general formulas (III) and (I
V), (V), (VI) Embedded image Embedded image Embedded image (Wherein, R ^{3 to} R ¹⁹ each independently represent a C 1 to C 1)
2 represents an alkyl group, a cycloalkyl group having 3 to 6 carbon atoms, an aryl group, or a hydrogen atom. Also, R ⁴ and R ⁵ , R
⁶ and R ⁷ , R ⁸ and R ⁹ , R ¹⁰ and R ¹¹ , R ¹² and R ¹³ , R ¹⁵ and R
¹⁶ , R ¹⁷ and R ¹⁸ may combine with each other to form a cycloalkyl group having 3 to 6 carbon atoms. Wherein Y ¹ is −
COOR ²⁰ , —COR ²⁰ or —SO ₂ R ²⁰ , Y ² is —
COOR ^{2 1,} -COR ²¹ or -SO ₂ R ^21, Y ³ is -
COOR ²² , —COR ²² or —SO ₂ R ²² , Y ⁴ is —
COOR ²³ , —COR ²³ or —SO ₂ R ²³ , and Y ⁵
Represents -COOR ²⁴ , -COR ²⁴ or -SO ₂ R ²⁴ , wherein R ²⁰ , R ²¹ , R ²² , R ²³ and R ²⁴ each independently represent an alkyl group having 1 to 12 carbon atoms, Number 3 ~
6 represents a cycloalkyl group or an aryl group. Where x
Represents an integer of 1 or 2. ), Wherein the alkyne derivative is contained in an amount of 0.1 to 10% by weight. 8. The content of the cyclic carbonate in the non-aqueous solvent is 10% by weight or more and 70% by weight or less, and the content of the chain carbonate is 30% by weight or more and 90% by weight or less. Non-aqueous electrolyte for lithium secondary batteries. 9. The non-aqueous electrolyte for a lithium secondary battery according to claim 7, wherein the cyclic carbonate is at least one selected from ethylene carbonate, propylene carbonate, butylene carbonate, and vinylene carbonate. 10. The non-aqueous electrolyte for a lithium secondary battery according to claim 7, wherein the chain carbonate is at least one selected from dimethyl carbonate, diethyl carbonate and methyl ethyl carbonate. 11. The non-aqueous electrolyte for a lithium secondary battery according to claim 7, wherein the graphite is natural graphite or artificial graphite. 12. The graphite lattice plane (002).
8. The non-aqueous electrolyte for a lithium secondary battery according to claim 7, wherein the plane spacing (d ₀₀₂ ) of the non-aqueous electrolyte is 0.335 to 0.340 nm.