JP2000348765A - Nonaqueous electrolytic solution and secondary battery using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrolytic solution capable of restraining the reduction decomposition reaction of a solvent even if highly crystalline carbon such as graphite is used for a negative electrode, of improving the service life of a battery and of imparting excellent charge-discharge efficiency, a load characteristic and a low-temperature characteristic by forming the electrolytic solution with a nonaqueous solvent containing a specific isocyanuric acid derivative and an electrolyte. SOLUTION: A nonaqueous solvent contains an isocyanuric acid derivative expressed by the formula I or formula II. In the formula I or formula II, R1-R3 may be the same or different, each being a 1-10C alkyl group, aryl group or a 1-20C organic group having a carbonyl group and/or an oxy group and/or a double bond. The formula I or formula II each are an isomer capable of being thermally isomerized. Preferably, in the case of this nonaqueous electrolytic solution, at least one of R1-R3 is a 1-10C hydrocarbon group that may contain at least one kind of group within an oxy group; oxo group, amide group and halogen in the compound expressed by the formula I or formula II.

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 having excellent charge / discharge characteristics and a secondary battery using the same. More specifically, the present invention relates to a non-aqueous electrolyte suitable for a lithium secondary battery containing an isocyanuric acid derivative, and a secondary battery using the same.

[0002]

BACKGROUND OF THE INVENTION A battery using a non-aqueous electrolyte has a high voltage, a high energy density, and a high reliability such as storability, so that it is widely used as a power source for consumer electronic devices. Have been.

As such a battery, there is a non-aqueous electrolyte secondary battery, a typical example of which is a lithium ion secondary battery. Carbonate compounds having a high dielectric constant are known as non-aqueous solvents used for such a purpose, and the use of various carbonate compounds has been proposed. As an electrolytic solution, LiBF ₄ , LiPF ₆ , LiPF ₆ , a mixed solvent of the high dielectric constant carbonate compound solvent such as propylene carbonate and ethylene carbonate, and a low viscosity solvent such as diethyl carbonate.
A solution in which an electrolyte such as LiClO ₄ , LiAsF ₆ , LiCF ₃ SO ₃ , or Li ₂ SiF ₆ is mixed is used.

[0004] On the other hand, research on electrodes has been promoted with the aim of increasing the capacity of batteries, and carbon materials capable of occluding and releasing lithium are used as negative electrodes of lithium ion secondary batteries. In particular, highly crystalline carbon such as graphite has characteristics such as a flat discharge potential, and is therefore used as most negative electrodes of currently commercially available lithium ion secondary batteries.

However, when highly crystalline carbon such as graphite is used for the negative electrode, propylene carbonate or 1,2-butylene carbonate, which is a high dielectric constant solvent having a low freezing point, is used as a non-aqueous solvent for the electrolytic solution. Occasionally, a reductive decomposition reaction of the solvent occurs, and the insertion reaction of lithium ions, which is an active material, into graphite hardly progresses, so that the function of the electrolytic solution is not fulfilled. As a result, the first charge / discharge efficiency is extremely reduced.

[0006] Therefore, as a non-aqueous solvent having a high dielectric constant, which is used in the electrolytic solution, ethylene carbonate, which is solid at room temperature but hardly undergoes a reductive decomposition reaction, is mixed with propylene carbonate to form a non-aqueous solvent. Attempts have been made to suppress the reductive decomposition reaction of the solvent. Furthermore, in order to improve the viscosity characteristics of the non-aqueous solvent in addition to suppressing the reductive decomposition reaction, devising a combination with a low-viscosity solvent, adding various additives, and reducing the content of propylene carbonate in the electrolytic solution. Restrictions have been proposed. These measures have improved the charge-discharge characteristics and low-temperature characteristics of the battery.However, furthermore, for example, when the high-temperature storage and charge-discharge cycles are repeated, the battery life caused by minute reductive decomposition reaction is reduced. There is a need for an electrolyte solution that can be improved and further improved low-temperature characteristics.

[0007]

SUMMARY OF THE INVENTION In order to meet the above demand, the present invention suppresses the reductive decomposition reaction of a solvent even when a highly crystalline carbon such as graphite is used for a negative electrode, thereby shortening the battery life. It is an object of the present invention to provide a non-aqueous electrolyte that improves the charge and discharge efficiency, load characteristics, and low-temperature characteristics of a battery. Another object is to provide a secondary battery including the non-aqueous electrolyte.

[0008]

The present invention provides a non-aqueous electrolyte comprising a non-aqueous solvent containing the following isocyanuric acid derivative and an electrolyte, and a secondary battery using the same. (1) A non-aqueous electrolytic solution comprising a non-aqueous solvent containing an isocyanuric acid derivative represented by the general formula [1a] or [1b] and an electrolyte.

Embedded image (In the formula [1a] or [1b], R ^{1 to} R ³ may be the same or different from each other, and may be an alkyl group having 1 to 10 carbon atoms, an aryl group, or a carbonyl group and / or an oxy group. And / or an organic group having a double bond and having 1 to 20 carbon atoms, and [1a] and [1b] are isomers that can be thermally isomerized.) (2) The general formula [1a] or The non-aqueous electrolyte according to claim 1, wherein the compound represented by [1b] has 1 to 6 carbon atoms in R ^{1 to} R ³ . (3) In the compound represented by the general formula [1a] or [1b], at least one of R ^{1 to} R ³ is an oxy group,
2. The non-aqueous electrolyte according to claim 1, wherein the non-aqueous electrolyte is a hydrocarbon group having 1 to 10 carbon atoms which may contain at least one of an oxo group, an amide group and a halogen. (4) In the compound represented by the general formula [1a] or [1b], at least one of R ^{1 to} R ³ is a group represented by the following general formula [2]. The non-aqueous electrolyte according to the above.

Embedded image (However, R ⁴ and R ⁵ may be the same or different from each other, and are hydrogen or a hydrocarbon group having 1 to 6 carbon atoms;
^{6 is} -OR ⁷ or

Embedded image (R ^{7 to} R ⁹ may be the same or different and represent a cation, hydrogen, or a hydrocarbon group having 1 to 6 carbon atoms), and n is an integer of 0 to 10. However, the group represented by the general formula [2] has 1 to 20 carbon atoms. (5) In the general formula [2], R ⁴ and R ⁵ may be the same or different and each is hydrogen, a methyl group, or an ethyl group, and R ^{6 is} —OR ⁷ (where R The electrolyte according to claim 4, wherein ⁷ is hydrogen or a hydrocarbon group having 1 to 6 carbon atoms, and n is an integer of 0 to 6). (6) In the compound represented by the general formula [1a] or [1b], R ^{1 to} R ³ are a methyl group, an ethyl group, a phenyl group, a carboxyethyl group, a methoxycarbonylethyl group, an ethoxycarbonylethyl group, an acryl 2. The non-aqueous electrolyte according to claim 1, which is any one of an oxyethyl group, a methacryloxyethyl group, and a methoxyethyl group. (7) In the compound represented by the general formula [1a] or [1b], at least ^one of R ^{1 to} R ³ is a carboxyl group, a carboxymethyl group, a carboxyethyl group, a methoxycarbonylmethyl group, an ethoxycarbonylmethyl group. The non-aqueous electrolyte according to claim 1, wherein the non-aqueous electrolyte is any one of a group, a methoxycarbonylethyl group, and an ethoxycarbonylethyl group. (8) The non-aqueous solvent is at least one of an isocyanuric acid derivative represented by the general formula [1a] or [1b] and a cyclic carbonate represented by the general formula [3a] or [3b] The non-aqueous electrolyte according to any one of claims 1 to 7, wherein the non-aqueous electrolyte contains a carbonic acid ester.

Embedded image (In the formula [3a] or [3b], R ^{4 to} R ⁷ may be the same or different from each other and are a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.) 9. The non-aqueous electrolyte according to claim 8, wherein the cyclic carbonate represented by the formula [3a] or [3b] is any one of ethylene carbonate, propylene carbonate, butylene carbonate, and vinylene carbonate. (10) The non-aqueous electrolyte according to (9), wherein the chain carbonate is any of dimethyl carbonate, diethyl carbonate, and methyl ethyl carbonate. (11) The isocyanuric acid derivative represented by the general formula [1a] or [1b] is added to the non-aqueous solvent in an amount of 0.
The non-aqueous electrolyte according to any one of claims 1 to 10, wherein the non-aqueous electrolyte is contained in an amount of from 01 to less than 5% by weight. (12) The above general formula [2a] or [2]
b] wherein the weight ratio of at least one cyclic carbonate to the chain carbonate is 15:85 to 55: 4.
The non-aqueous electrolyte according to claim 8, wherein the number is 5. (13) The non-aqueous electrolyte according to any one of claims 1 to 112, wherein the electrolyte is a lithium salt. (14) A secondary battery comprising the non-aqueous electrolyte according to any one of claims 1 to 13. (15) Metallic lithium, lithium-containing alloy, or carbon material capable of doping and undoping lithium ions, tin oxide capable of doping and undoping lithium ions, and doping and undoping of lithium ions as a negative electrode active material Negative electrode containing either pure titanium oxide or silicon capable of doping and undoping lithium ions, and transition metal oxides, transition metal sulfides, composite oxides of lithium and transition metals as positive electrode active materials, and high conductivity A positive electrode comprising any one of a molecular material, a carbon material, and a mixture thereof, and a cathode.
A lithium ion secondary battery comprising any one of the non-aqueous electrolytes according to any one of Claims 1 to 14. (16) The carbon material capable of doping / dedoping lithium ions has a plane distance (d002) on the (002) plane measured by X-ray analysis of 0.340 nm or less. 16. The lithium ion secondary battery according to 15.

[0009]

Next, the non-aqueous electrolyte according to the present invention and a non-aqueous electrolyte secondary battery using this non-aqueous electrolyte will be described in detail. The non-aqueous electrolyte according to the present invention comprises a non-aqueous solvent containing an isocyanuric acid derivative and an electrolyte, each of which will be described in detail.

[0010] general formula as isocyanuric acid derivative to be contained in the nonaqueous solvent isocyanuric acid derivative present invention [1a] or the compound represented by [1b] can be used.

Embedded image (In the formula [1a] or [1b], R ^{1 to} R ³ may be the same or different from each other, and may be an alkyl group having 1 to 10 carbon atoms, an aryl group, or a carbonyl group and / or an oxy group. And / or an organic group containing a double bond and having 1 to 20 carbon atoms, and [1a] and [1b].
Is an isomer that can be thermally isomerized. The compound [1a] and the compound [1b] are isomers capable of undergoing a thermal isomerization reaction, and usually exist in the form of [1a] under neutral or acidic conditions, and gradually become [1b] when [1a] is heated. Isomerizes. In the present invention, either [1a] or [1b] may be used.

Examples of the C1-C10 alkyl group, aryl group, or carbonyl group and / or oxy group and / or C1-C20 organic group containing a double bond include a methyl group, Ethyl group, vinyl group, propyl group, isopropyl group, 1-propenyl group, 2-propenyl group, acrylic group, methacryl group, carboxyl group,
Methoxycarbonyl group, ethoxycarbonyl group, methoxycarbonyloxy group, ethoxycarbonyloxy group,
Acryloxyethyl group, methacryloxyethyl group,
Carboxylethyl group, methoxycarbonylethyl group,
Ethoxycarbonylethyl group, methoxycarbonyloxyethyl group, ethoxycarbonyloxyethyl group, 1-propynyl group, 2-propynyl group, butyl group, isobutyl group, sec-butyl group, t-butyl group, 1-butenyl group, 2- Butenyl group, 3-butenyl group, 2-methyl-2-propenyl group, 1-
Methylenepropyl group, 1-methyl-2-propenyl group, 1,2-
Dimethylvinyl group, 1-butynyl group, 2-butynyl group, 3-butynyl group, pentyl group, 1-methylbutyl group, 2-methylbutyl group, 3-methylbutyl group, 1-methyl-2-methylpropyl group, 2,2 -Dimethylpropyl group, phenyl group, o-, p-, m-
A phenyl group substituted at the position with a methyl group, a phenyl group substituted at the o-, p-, m-position with an ethyl group, a phenyl group substituted at the o-, p-, m-position with a propyl group, o-, p a phenyl group in which the-, m-position is substituted with a methoxy group, a phenyl group in which the o-, p-, m-position is substituted with an ethoxy group, and other carbon atoms such as hexyl group, octyl group, nonyl group and decyl group And 10 to 10 linear or branched alkyl groups or aryl groups.

In view of the solubility of the additive in the electrolytic solution, R ¹
The number of carbon atoms in R ³ is preferably 6 or less. Further, in the present invention, when at least one of R ^{1 to} R ³ is represented by the following general formula [2], the compound exhibits an appropriate solubility in an electrolytic solution, and reductive decomposition of the electrolytic solution on a negative electrode. It is particularly preferable because the inhibitory action is particularly excellent.

Embedded image (However, R ⁴ and R ⁵ may be the same or different from each other, and are hydrogen or a hydrocarbon group having 1 to 6 carbon atoms;
⁶ is -OR ⁷ or

Embedded image (R ^{7 to} R ⁹ may be the same or different and represent a cation, hydrogen, or a hydrocarbon group having 1 to 6 carbon atoms), and n is an integer of 0 to 10. However, the group represented by the general formula [2] has 1 to 20 carbon atoms. )

Specific examples of the compound represented by the general formula [1a] or [1b] include the following compounds. Trimethyl isocyanurate, triethyl isocyanurate, triphenoxytriazine, tricarboxyethyl isocyanurate, trimethoxycarboxyethyl isocyanurate, triethoxycarboxyethyl isocyanurate, trimethoxycarboxyoxyethyl isocyanurate, triethoxycarboxyoxyethyl isocyanurate, isocyanuric acid Triacryloxyethyl, trimethacryloxyethyl isocyanurate, trivinyl isocyanurate, triallyl isocyanurate, trimethallyl isocyanurate, methyl diisocyanurate (carboxyethyl), dimethyl isocyanurate (carboxyethyl), ethyl diisocyanurate (carboxyethyl), isocyanuric acid Diethyl (carboxylethyl), isocyanuric acid pro Distearate (carboxyethyl) isocyanuric acid dipropyl (carboxyethyl) isocyanurate divinyl (carboxyethyl) isocyanurate vinyl (carboxyethyl) isocyanuric acid diallyl (carboxyethyl) isocyanuric acid allyl (carboxyethyl)
Triglycidyl isocyanurate, tri (carboxymethyl) isocyanurate, tri (carboxy) isocyanurate, tri (carboxypropyl) isocyanurate, tri (carboxybutyl) isocyanurate, tri (methoxycarbonylmethyl) isocyanurate, tri (ethoxycarbonyl) isocyanurate Carbonylmethyl), isocyanuric acid tri (methoxycarbonyl), isocyanuric acid tri (ethoxycarbonyl), isocyanuric acid di (carboxyethyl) (methoxycarbonylethyl), isocyanuric acid (carboxyethyl) di (methoxycarbonylethyl), isocyanuric acid di ( Carboxyethyl) (ethoxycarbonylethyl), isocyanuric acid (carboxyethyl) di (ethoxycarbonylethyl), isocyanuric acid (trimethylsilyloxy) Ruboniruechiru), and the like.

The above general formula [1a] or [1]
The isocyanuric acid derivative represented by b] has the effect of suppressing the reductive decomposition reaction of the nonaqueous solvent during charging and improving the charge / discharge efficiency.

Non-Aqueous Solvent In the non-aqueous electrolyte according to the present invention, a non-aqueous solvent containing the isocyanuric acid derivative represented by the general formula [1a] or [1b] is used. This isocyanuric acid derivative is
It can be used as an additive to commonly used non-aqueous solvents.

In the present invention, a non-aqueous solvent containing the above isocyanuric acid derivative and at least one cyclic carbonate represented by the following general formula [3a] or [3b] and / or a chain carbonate is used. It is desirable to do.

Examples of the non-aqueous solvent that can be used include at least one of cyclic carbonates represented by the following general formulas [3a] and [3b] and / or chain carbonates.

Embedded image (In the formula [3a] or [3b], R ^{4 to} R ⁷ may be the same or different from each other and are a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.) Is preferably an alkyl group having 1 to 3 carbon atoms, and specific examples thereof include a methyl group, an ethyl group, and an n-propyl group.

Specific examples of the cyclic carbonate represented by the general formula [3a] or [3b] include ethylene carbonate, propylene carbonate, 1,2-butylene carbonate, 2,3-butylene carbonate,
Examples thereof include 2-pentylene carbonate, 2,3-pentylene carbonate, and vinylene carbonate. In particular, ethylene carbonate and propylene carbonate having a high dielectric constant are preferably used. When the improvement of the battery life is particularly intended, ethylene carbonate is particularly preferable. These cyclic carbonates may be used as a mixture of two or more kinds.

Specific examples of the chain carbonate include dimethyl carbonate, methyl ethyl carbonate, diethyl carbonate, methyl propyl carbonate, methyl isopropyl carbonate, ethyl propyl carbonate and the like. In particular, dimethyl carbonate, methyl ethyl carbonate, and diethyl carbonate having low viscosity are preferably used. These chain carbonates may be used as a mixture of two or more.

Specific examples of the combination of the cyclic carbonate and the chain carbonate of the non-aqueous solvent include ethylene carbonate and dimethyl carbonate, ethylene carbonate and methyl ethyl carbonate, ethylene carbonate and diethyl carbonate, propylene carbonate and dimethyl carbonate, and propylene carbonate. And methyl ethyl carbonate, propylene carbonate and diethyl carbonate, ethylene carbonate and propylene carbonate and dimethyl carbonate, ethylene carbonate and propylene carbonate and methyl ethyl carbonate,
Ethylene carbonate and propylene carbonate and diethyl carbonate, ethylene carbonate and dimethyl carbonate and methyl ethyl carbonate, ethylene carbonate and dimethyl carbonate and diethyl carbonate, ethylene carbonate and propylene carbonate and dimethyl carbonate and methyl ethyl carbonate, ethylene carbonate and propylene carbonate and dimethyl carbonate Diethyl carbonate and the like.

When such a chain carbonate is contained in a non-aqueous solvent, the viscosity of the non-aqueous electrolyte can be reduced, the solubility of the electrolyte can be further increased, and the electric conductivity at normal temperature or low temperature can be improved. It is possible to obtain an electrolytic solution having excellent properties.
Therefore, it is possible to improve the charge / discharge efficiency of the battery and low-temperature characteristics such as, for example, the charge / discharge efficiency at low temperatures and the load characteristics at low temperatures.

The amount of the isocyanuric acid derivative represented by the general formula [1a] or [1b] is determined by the total amount of the non-aqueous solvent containing it (the isocyanuric acid derivative represented by the general formula [1a] or [1b]). And at least one of the cyclic carbonates represented by the general formula [2a] or [2b] and / or the chain carbonate)) in an amount of 0.001% by weight or more, preferably 0.1% by weight or less. 01% by weight
Not less than 5% by weight, more preferably 0.05% by weight
-4% by weight, particularly preferably 0.1-3% by weight. No.

In such a mixing ratio, the above general formula [1a]
Alternatively, when the isocyanuric acid derivative represented by [1b] is contained in the entire non-aqueous solvent containing the same, the reductive decomposition reaction of the solvent that occurs at the time of charging can be suppressed low, and the battery has high-temperature storage characteristics and cycle characteristics. It is possible to improve the life, improve the charge / discharge efficiency of the battery, and improve the low-temperature characteristics.

In the non-aqueous solvent, the above-mentioned general formula [3a]
Alternatively, the mixing ratio when simultaneously containing at least one of the cyclic carbonates represented by [3b] and the chain carbonate is represented by the above-mentioned general formula [2a] or [2b] in terms of weight ratio. At least one of the cyclic carbonates: 0: 100 to 100: 0;
Preferably 5:95 to 80:20, more preferably 1
0: 90-70: 30, particularly preferably 15: 85-5
5:45. By making such a ratio,
Since the increase in the viscosity of the electrolyte can be suppressed and the degree of dissociation of the electrolyte can be increased, the conductivity of the electrolyte relating to the charge / discharge characteristics of the battery can be increased.

Therefore, a preferred non-aqueous solvent according to the present invention is a compound comprising an isocyanuric acid derivative represented by the general formula [1a] or [1b] and a cyclic carbonate represented by the general formula [3a] or [3b] It contains at least one kind of ester and / or the above-mentioned chain carbonate. In addition to these, it is also possible to further mix or add a small amount of a solvent which is widely used as a non-aqueous solvent for batteries.

In the non-aqueous electrolyte according to the present invention, when the isocyanuric acid derivative is mixed with a non-aqueous solvent and used, the non-aqueous solvent is replaced with the above-mentioned carbonate, or in addition to the above-mentioned carbonate, other than the above-mentioned carbonate, May be used as the other solvent, specifically, methyl formate,
Ethyl formate, propyl formate, methyl acetate, ethyl acetate,
Chain esters such as propyl acetate, methyl propionate, ethyl propionate, methyl butyrate, and methyl valerate; phosphate esters such as trimethyl phosphate; 1,2-dimethoxyethane, 1,2-diethoxyethane, diethyl ether, Chain ethers such as dimethyl ether, methyl ethyl ether and dipropyl ether; 1,4-dioxane, 1,3-dioxolan, tetrahydrofuran, 2-methyltetrahydrofuran, 3-methyl-1,3-dioxolan, 2-methyl-1, Cyclic ethers such as 3-dioxolane; amides such as dimethylformamide; linear carbamates such as methyl-N, N-dimethylcarbamate; γ-butyrolactone, γ-valerolactone, 3-methyl-γ-butyrolactone, 2-methyl-γ -
Cyclic esters such as butyrolactone; cyclic sulfones such as sulfolane; cyclic carbamates such as N-methyloxazolidinone; cyclic amides such as N-methylpyrrolidone; cyclic ureas such as N, N-dimethylimidazolidinone; 4,4-dimethyl-5 -Methylene ethylene carbonate, 4
-Methyl-4-ethyl-5-methyleneethylene carbonate, 4
-Methyl-4-propyl-5-methyleneethylene carbonate, 4-methyl-4-butyl-5-methyleneethylene carbonate, 4,4-diethyl-5-methyleneethylene carbonate, 4
-Ethyl-4-propyl-5-methyleneethylene carbonate, 4-ethyl-4-butyl-5-methyleneethylene carbonate, 4,4-dipropyl-5-methyleneethylene carbonate, 4-propyl-4-butyl-5-methylene Ethylene carbonate, 4,4-dibutyl-5-methyleneethylene carbonate, 4,4-dimethyl-5-ethylideneethylene carbonate, 4-methyl-4-ethyl-5-ethylideneethylene carbonate, 4-methyl-4-propyl-5 -Ethylidene ethylene carbonate, 4-methyl-4-butyl-5-ethylidene ethylene carbonate, 4,4-diethyl-5-ethylidene ethylene carbonate, 4-ethyl-4-propyl-5-ethylidene ethylene carbonate, 4-ethyl-4 -Butyl-5-ethylidene ethylene carbonate, 4,4-dipropyl-5-ethylidene ethylene carbonate, 4-propyl-4-butyl-5-ethylidene ethylene carbonate G, 4,4-dibutyl-5-ethylideneethylene carbonate, 4-methyl-4-vinyl-5-methyleneethylene carbonate, 4-methyl-4-allyl-5-methyleneethylene carbonate, 4-methyl-4-methoxymethyl Cyclic carbonates such as -5-methyleneethylene carbonate, 4-methyl-4-acryloxymethyl-5-methyleneethylene carbonate, 4-methyl-4-allyloxymethyl-5-methyleneethylene carbonate; 4-vinylethylene carbonate; Vinyl ethylene carbonate derivatives such as 4,4-divinyl ethylene carbonate and 4,5-divinyl ethylene carbonate; 4-vinyl-4-methylethylene carbonate, 4-vinyl-5-methylethylene carbonate, 4-vinyl-4,5- Dimethyl ethylene carbonate, 4-vinyl-5,5-
Alkyl-substituted vinyl ethylene carbonate derivatives such as dimethyl ethylene carbonate and 4-vinyl-4,5,5-trimethyl ethylene carbonate; allyloxymethyl ethylene carbonate such as 4-allyloxymethyl ethylene carbonate and 4,5-diallyloxymethyl ethylene carbonate Derivatives; alkyl-substituted allyloxymethylethylene carbonate derivatives such as 4-methyl-4-allyloxymethylethylene carbonate and 4-methyl-5-allyloxymethylethylene carbonate; 4-acryloxymethylethylene carbonate, 4,5-acryloxy Acryloxymethylethylene carbonate derivatives such as methylethylene carbonate; 4-methyl-4-acryloxymethylethylene carbonate, 4-methyl-5-acryloxymethylethylene carbonate, etc. Alkyl-substituted acrylic oxymethyl ethylene carbonate derivatives; and the like, and a compound represented by the following general formula; sulfolane, sulfur-containing compounds such as dimethyl sulfate; trimethyl phosphate, phosphorous compounds such as triethylphosphate. HO (CH ₂ CH ₂ O) _a H, HO ｛CH ₂
CH (CH ₃ ) O｝ _bH , CH ₃ O (CH ₂ CH ₂ O)
_c H, CH ₃ O ｛CH ₂ CH (CH ₃ ) O｝ _d H, CH ₃ O
(CH ₂ CH ₂ O) _e CH ₃ , CH ₃ O ｛CH ₂ CH (C
H ₃ ) O｝ _f CH ₃ , C ₉ H ₁₉ PhO (CH ₂ CH ₂ O) _g
{CH (CH ₃ ) O} _h CH ₃ (Ph is a phenyl group), C
H ₃ O ｛CH ₂ CH (CH ₃ ) O｝ _i CO ｛O (CH ₃ ) C
HCH ₂ ｝ _j OCH ₃ (where a to f are from 5 to 250
And g to j are integers of 2 to 249, and 5 ≦ g + h ≦ 25.
0, 5 ≦ i + j ≦ 250. Specific examples of mixing of the non-aqueous solvent in the present invention include the above-described isocyanuric acid derivative and cyclic carbonate and γ-butyrolactone, the isocyanuric acid derivative and cyclic carbonate and chain carbonate and γ-butyrolactone, or In the same combination, those using a phosphoric acid ester or sulfolane instead of γ-butyrolactone are exemplified.

The non-aqueous electrolytic solution The non-aqueous electrolyte solution of the present invention is formed of a non-aqueous solvent containing an isocyanuric acid derivative described above and an electrolyte, for example aqueous containing a compound containing an isocyanuric acid derivative described above It is obtained by dissolving an electrolyte in a solvent. As the electrolyte to be used, any electrolyte which is usually used as an electrolyte for a non-aqueous electrolyte can be used.

As a specific example of the electrolyte, LiPF₆, Li
BF_Four, LiClO_Four, LiAsF₆, Li _TwoSiF₆, LiC_FourF
₉SO_Three, LiC₈F₁₇SO_ThreeLithium salts such as
You. In addition, a lithium salt represented by the following general formula is also used.
be able to. LiOSO_TwoR⁸, Lin (SO_TwoR⁹) (S
O_TwoR^Ten), LiC (SO_TwoR¹¹) (SO_TwoR¹²) (SO_Two
R¹³), LiN (SO_TwoOR¹⁴) (SO_TwoOR¹⁵)(here
And R⁸~ R¹⁵Are the same but different
And a perfluoroalkyl group having 1 to 6 carbon atoms.
). These lithium salts may be used alone or
Or two or more of them may be used in combination.

Among these, in particular, LiPF ₆ and LiB
F ₄ , LiOSO ₂ R ⁸ , LiN (SO ₂ R ⁹ ) (SO
^{_{2 R 10), LiC (SO}} 2 R 11) (SO 2 R 12) (SO 2 R
¹³ ), and LiN (SO ₂ OR ¹⁴ ) (SO ₂ OR ¹⁵ ) are preferred.

It is desirable that such an electrolyte is usually contained in the non-aqueous electrolyte at a concentration of 0.1 to 3 mol / l, preferably 0.5 to 2 mol / l.

The non-aqueous electrolytic solution in the present invention contains a non-aqueous solvent containing an isocyanuric acid derivative represented by the above general formula [1a] or [1b] and an electrolyte as essential components. Other additives and the like may be added.

The non-aqueous electrolyte according to the present invention as described above comprises:
Not only is it suitable as a non-aqueous electrolyte for lithium ion secondary batteries, but it can also be used as a non-aqueous electrolyte for primary batteries.

The non-aqueous electrolyte secondary battery according to the secondary batteries present invention, a negative electrode, a positive electrode,
The non-aqueous electrolyte is basically configured to include,
Usually, a separator is provided between the negative electrode and the positive electrode.

The negative electrode active material constituting the negative electrode includes metallic lithium, a lithium alloy, a carbon material capable of doping and undoping lithium ions, tin oxide capable of doping and undoping lithium ions, and lithium. Titanium oxide capable of doping and undoping ions
Alternatively, any of silicon capable of doping and undoping lithium ions can be used. Among these, a carbon material capable of doving / de-doping lithium ions is preferable. Such a carbon material may be graphite or amorphous carbon, and activated carbon, carbon fiber, carbon black, mesocarbon microbeads, natural graphite and the like are used.

As the negative electrode active material, the (002) plane spacing (d002) measured by X-ray analysis was 0.340 nm.
The following carbon materials are preferable, and the density is 1.70 g / cm ³
The graphite described above or a highly crystalline carbon material having properties similar thereto is desirable. When such a carbon material is used, the energy density of the battery can be increased.

As the positive electrode active material constituting the positive electrode, Mo is used.
Transition metal oxides or sulfides such as S ₂ , TiS ₂ , MnO ₂ , V ₂ O ₅ , LiCoO ₂ , LiMnO ₂ , LiMn _{2
O 4, LiNiO 2, LiNi X} Co (1-X) composite oxide comprising lithium such as O ₂ and a transition metal, polyaniline, polythiophene, polypyrrole, polyacetylene, polyacene, conductivity, such as dimercaptothiadiazole / polyaniline complex Polymer materials and the like can be mentioned. Among these, a composite oxide composed of lithium and a transition metal is particularly preferable. When the negative electrode is a lithium metal or lithium alloy, a carbon material can be used as the positive electrode.
Further, as the positive electrode, a mixture of a composite oxide of lithium and a transition metal and a carbon material can be used.

The separator is a porous membrane, and usually a microporous polymer film is suitably used. In particular, a porous polyolefin film is preferable, and specific examples thereof include a porous polyethylene film, a porous polypropylene film, and a multilayer film of a porous polyethylene film and polypropylene.

Such a non-aqueous electrolyte secondary battery can be formed in a cylindrical shape, a coin shape, a square shape, or any other shape. However, the basic structure of the battery is the same regardless of the shape, and the design can be changed according to the purpose. Next, the structures of the cylindrical and coin type batteries will be described. The negative electrode active material, the positive electrode active material, and the separator constituting each battery are commonly used.

For example, in the case of a cylindrical non-aqueous electrolyte secondary battery, a negative electrode obtained by applying a negative electrode active material to a negative electrode current collector;
A positive electrode formed by applying a positive electrode active material to a positive electrode current collector is wound through a severator in which a non-aqueous electrolyte is injected, and is housed in a battery can with an insulating plate placed above and below the wound body. ing.

The non-aqueous electrolyte secondary battery according to the present invention can be applied to a coin-type non-aqueous electrolyte secondary battery. In a coin-type battery, a disk-shaped negative electrode, a separator, a disk-shaped positive electrode, and a stainless steel plate are housed in a coin-type battery can in a state of being stacked in this order.

[0041]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described specifically with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.

[0042]

Example 1 <Preparation of non-aqueous electrolyte> Propylene carbonate (PC) and diethyl carbonate (DEC) were
After mixing at a ratio of PC: DEC = 55: 45 (weight ratio), 1 part by weight of tricarboxyethyl isocyanurate was added to 99 parts by weight of the mixed solvent, and the content (dissolved amount) of the isocyanuric acid derivative was added. Is the entire non-aqueous solvent (PC and D
A non-aqueous solvent was prepared so as to be (20/99)% by weight [about 0.2% by weight] based on the total amount of EC and tricarboxyethyl isocyanurate. Next, the electrolyte LiP
F ₆ was dissolved in a non-aqueous solvent to prepare a non-aqueous electrolyte so that the electrolyte concentration was 1.0 mol / l.

<Preparation of Negative Electrode> Mesocarbon microbeads (trade name: MCMB6-28, d, manufactured by Osaka Gas Co., Ltd.)
002 = 0.337 nm, 90 parts by weight of carbon powder having a density of 2.17 g / cm ³ ) and 10 parts by weight of polyvinylidene fluoride (PVDF) as a binder were mixed, and N-
The paste was dispersed in methylpyrrolidone to prepare a paste-like negative electrode mixture slurry. Next, this negative electrode mixture slurry was applied to a negative electrode current collector made of a 20-μm-thick strip-shaped copper foil, and dried to obtain a strip-shaped carbon negative electrode. The thickness of the negative electrode mixture after drying is 2
It was 5 μm. Furthermore, this strip electrode is 15 mm in diameter.
, And compression molded to form a negative electrode.

<Preparation of Positive Electrode> L manufactured by Honjo Chemical Co., Ltd.
iCoO ₂ (product name: HLC-21, average particle size 8 μm)
91 parts by weight of fine particles, 6 parts by weight of graphite as a conductive material, and polyvinylidene fluoride (PVD) as a binder
F) was mixed with 3 parts by weight to prepare a positive electrode mixture, and dispersed in N-methylpyrrolidone to obtain a positive electrode mixture slurry. This slurry was applied to a 20-μm-thick aluminum foil positive electrode current collector, dried, and compression-molded to obtain a belt-shaped positive electrode. The thickness of the positive electrode mixture after drying was 40 μm.
Thereafter, the strip-shaped electrode was punched into a disk having a diameter of 15 mm to obtain a positive electrode.

<Preparation of Battery> A disk-shaped negative electrode and a disk-shaped positive electrode thus obtained, and a separator made of a microporous polypropylene film having a thickness of 25 μm and a diameter of 19 mm were prepared. After each of the negative electrode, the separator, and the positive electrode were laminated in the order of a 2032-sized stainless steel battery can, the nonaqueous electrolyte was injected into the separator.
Then, a stainless steel plate (2.4 m thick) was placed in the battery can.
m, diameter 15.4 mm), and the battery can (lid) was caulked via a gasket made of polypropylene.
As a result, the airtightness in the battery can be maintained, the diameter is 20 mm,
A button-type nonaqueous electrolyte secondary battery having a height of 3.2 mm was obtained.

<Measurement of Charge / Discharge Efficiency> The charge / discharge efficiency of the secondary battery thus obtained was measured at room temperature by the following method. In this example, the current direction in which the negative electrode was doped with Li ions was defined as charging, and the current direction in which undoping was performed was defined as discharging. Charging was performed by a 4.1 V, 1 mA constant current, constant voltage charging method, and was terminated when the charging current became 50 μA or less. Discharge was performed at a constant current of 1 mA, and the voltage was 2.7 V.
It ended when it reached. From the charge capacity and the discharge capacity of this charge / discharge cycle, the charge / discharge efficiency is calculated by the following equation,
The results are shown in Table 1. Charge / discharge efficiency (%) = {discharge capacity (mAh / g)} / ｛charge capacity (mA
h / g)｝ × 100

[0047]

Comparative Example 1 A non-aqueous electrolyte was prepared and a battery was prepared in the same manner as in Example 1 except that no isocyanuric acid derivative was added. Was evaluated for charge and discharge efficiency. The results are shown in Table 1.

[0048]

[Table 1]

(2) Measurement of Leakage Current <Preparation of Negative Electrode> Natural Graphite (LF-18A made by Chuetsu Graphite) 8
7 parts by weight and polyvinylidene fluoride (PVDF) as a binder
13 parts by weight were mixed and dispersed in N-methylpyrrolidinone as a solvent to prepare a natural graphite mixture slurry. Next, this negative electrode mixture slurry was applied to a 18-μm-thick strip-shaped negative electrode current collector made of copper foil, dried, and then compression-molded.
A 4 mm disk was punched out to obtain a coin-shaped natural graphite electrode. This natural graphite electrode mixture had a thickness of 110 microns and a weight of 20 mg / Φ14 mm. <Production of Battery> The coin-type battery shown in FIG. 1 was produced.
Natural graphite electrode 14 with a diameter of 14 mm, diameter 16 mm and thickness of 0.1 mm.
A lithium metal foil 13 having a thickness of 3 mm and a separator 15 made of a microporous polypropylene film having a thickness of 25 μm and a diameter of 19 mm were placed in a stainless steel battery can 16 having a size of 322.
5. Laminated in the order of natural graphite electrode 14. Thereafter, 0.05 ml of the non-aqueous electrolyte was injected into the separator, and a stainless steel plate 17 (1.2 mm thick, 15.5 mm in diameter,
And the spring 20 were stored. Finally, the airtightness inside the battery was maintained by caulking the battery can lid 19 via a polypropylene gasket 18 to produce a coin-type Li-natural graphite battery having a diameter of 20 mm and a height of 3.2 mm. . <Measurement of the amount of electrolysis on natural graphite electrode (measurement of leakage current)> The amount of electrolysis of the electrolytic solution on the natural graphite electrode was measured by measuring leakage current described below. First, the coin-type Li-natural graphite battery is discharged for 10 hours under the condition of 1 mA constant current and 0 V constant voltage, and then charged for 10 hours under the condition of 1 mA constant current and 1.2 V constant voltage. Was. Subsequently, discharging for a total of 5 hours under the condition of 2 mA constant current and 0 V constant voltage, and then performing charging for a total of 5 hours under the condition of 2 mA constant current and 1.2 V constant voltage are defined as one cycle.
Two cycles of discharging and charging were performed. Further, discharge was performed for 10 hours under the condition of a constant current of 2 mA and a constant voltage of 0.01 V. Thereafter, the temperature of the battery was raised to 60 ° C., and 0.2 mA
The discharge was continued for a total of 25 hours under the conditions of a constant current and a constant voltage of 0.01 V, and changes in the current flowing at this time were tracked. This current value rapidly attenuates immediately after the start of discharge at 60 ° C., and becomes substantially constant after 15 hours or more. The current that continues to flow by this fixed amount corresponds to the amount of electrolysis of the electrolytic solution on the natural graphite electrode, and the current value measured at 25 hours was defined as “leakage current”. The value of the leakage current was normalized by the weight of the natural graphite used for the measurement.

[Table 2] As described above, in the electrolytic solution of the present invention, the leakage current representing the amount of electrolysis of the electrolytic solution on the natural graphite electrode is small, indicating that the electrolytic solution of the electrolytic solution is suppressed. 3) High-temperature storage test <Preparation of non-aqueous electrolyte> Ethylene carbonate (EC) and dimethyl carbonate (DMC) were mixed with EC: DMC =
40:60 (weight ratio), or ethylene carbonate (EC) and methyl ethyl carbonate (MEC)
After mixing at a ratio of EC: MEC = 40: 60 (weight ratio), a predetermined amount of an isocyanuric acid derivative was added to the mixed solvent to prepare a solvent. Next, the electrolyte, LiPF
6 was dissolved in a non-aqueous solvent to prepare a non-aqueous electrolyte so that the electrolyte concentration was 1.0 mol / l. <Preparation of Negative Electrode> Natural Graphite (LF-18A made by Chuetsu Graphite) 8
7 parts by weight and polyvinylidene fluoride (PVDF) as a binder
13 parts by weight were mixed and dispersed in N-methylpyrrolidinone as a solvent to prepare a natural graphite mixture slurry. Next, this negative electrode mixture slurry was applied to a 18-μm-thick strip-shaped negative electrode current collector made of copper foil, dried, and then compression-molded.
A 4 mm disk was punched out to obtain a coin-shaped natural graphite electrode. This natural graphite electrode mixture had a thickness of 110 microns and a weight of 20 mg / Φ14 mm. <Production of LiCoO ₂ electrode> LiCoO ₂ (Honjo FMC
90 parts by weight of HLC-21 manufactured by Energy Systems Co., Ltd., 6 parts by weight of graphite as a conductive agent and acetylene black 1
Parts by weight and 3 parts by weight of polyvinylidene fluoride as a binder were mixed and dispersed in N-methylpyrrolidone as a solvent.
An O ₂ mixture slurry was prepared. This LiCoO ₂ mixture slurry is applied to an aluminum foil having a thickness of 20 microns and dried,
Compression molding, this is Φ13mm, LiCoO
_Two electrodes were fabricated. This LiCoO ₂ mixture had a thickness of 90 microns and a weight of 35 mg / Φ13 mm. <Production of Battery> A coin-type battery shown in FIG. 2 was produced.
14 mm diameter natural graphite electrode 13, 13 mm diameter LiC
oO ₂ electrode 14, separator 15 made of microporous polypropylene film having a thickness of 25 μm and a diameter of 16 mm
In a 2032 stainless steel battery can 16
The natural graphite electrode 13, the separator 15, and the LiCoO ₂ electrode 14 were laminated in this order. Thereafter, 0.03 ml of the non-aqueous electrolyte was injected into the separator, and the aluminum plate 17 was removed.
(A thickness of 1.2 mm, a diameter of 16 mm, and a spring 20 were housed. Finally, the battery can (lid) 19 was caulked via a polypropylene gasket 18 to maintain the airtightness of the battery. A coin-type battery having a diameter of 20 mm and a height of 3.2 mm was prepared <Measurement of load characteristics after high-temperature storage> The coin battery prepared as described above was used, and the battery was charged at a constant current of 0.5 mA.
The battery was charged under the condition of 2V constant voltage until the current value at the time of 4.2V constant voltage became 0.05 mA, and then the current at the time of 3.0V constant voltage under the condition of 1mA constant current and 3.0V constant voltage. The battery was discharged until the value reached 0.05 mA. Next, this battery was charged under the condition of a constant current of 3.85 V and a constant current of 3.85 V until the current value at a constant voltage of 3.85 V became 0.05 mA.
Thereafter, the battery was stored at a high temperature for 24 hours in a thermostat at 60 ° C. After storage at a high temperature, under the conditions of a constant current and a constant voltage of 1 mA, the end condition was a current value of 0.05 mA at the time of a constant voltage. Discharge capacity). Next, the battery was charged to 4.2 V under the same conditions, and then discharged at a constant current of 10 mA and the discharge was terminated when the battery voltage reached 3.0 V, and the discharge capacity was measured (high-load discharge). Capacity). Then, the ratio of the high-load discharge capacity to the low-load discharge capacity at this time was determined and determined as a load characteristic index. <Measurement Results> The following table (Table 3) shows the electrolytes used in the examples and the measurement results of the load characteristic index.

[Table 3]

[0050]

The non-aqueous electrolyte of the present invention can suppress the reductive decomposition reaction of the solvent which occurs when highly crystalline carbon such as graphite is used for the negative electrode. As a result, a secondary battery using this non-aqueous electrolyte is excellent in battery life such as high-temperature storage characteristics and cycle characteristics, charge / discharge characteristics, load characteristics, and battery characteristics at low temperatures. Therefore, this non-aqueous electrolyte is particularly suitable as a non-aqueous electrolyte for a lithium ion secondary battery.

[0051]

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing one embodiment of a non-aqueous electrolyte secondary battery of the present invention.

FIG. 2 is a schematic sectional view of a coin-type battery used in an embodiment of the present invention.

[Explanation of symbols]

 1, 13 ... negative electrode 2, 14 ... positive electrode 3, 15 ... separator 4: ... insulating plate 5, 16 ... battery can 6 ... sealing gasket 7 ... battery lid 8 ... thin plate for current interruption 9 ... -Negative electrode current collector 10-Positive electrode current collector 11-Negative electrode lead 12-Positive electrode lead 17-Aluminum plate 18-Gasket 19-Battery can (lid) 20- ·Spring

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5H003 AA01 AA04 BB02 BB04 BB06 BD02 5H014 AA06 EE08 EE10 HH06 5H029 AJ02 AJ05 AK02 AK03 AK05 AL02 AL07 AL08 AM02 AM03 AM07 HJ02 HJ04

Claims (16)

[Claims] 1. A non-aqueous electrolytic solution comprising a non-aqueous solvent containing an isocyanuric acid derivative represented by the general formula [1a] or [1b] and an electrolyte. Embedded image (In the formula [1a] or [1b], R ^{1 to} R ³ may be the same or different from each other, and may be an alkyl group having 1 to 10 carbon atoms, an aryl group, or a carbonyl group and / or an oxy group. And / or an organic group containing a double bond and having 1 to 20 carbon atoms, and [1a] and [1b].
Is an isomer that can be thermally isomerized. ) 2. The non-aqueous electrolyte according to claim 1, wherein in the compound represented by the general formula [1a] or [1b], R ^{1 to} R ³ have 1 to 6 carbon atoms. liquid. 3. The compound represented by the general formula [1a] or [1b], wherein at least one of R ^{1 to} R ³ is at least one of an oxy group, an oxo group, an amide group and a halogen. The non-aqueous electrolyte according to claim 1, which is a hydrocarbon group having 1 to 10 carbon atoms that may be contained. 4. The compound represented by the general formula [1a] or [1b], wherein at least one of R ^{1 to} R ³ is a group represented by the following general formula [2]. Item 2. The non-aqueous electrolyte according to Item 1. Embedded image (However, R ⁴ and R ⁵ may be the same or different from each other, and are hydrogen or a hydrocarbon group having 1 to 6 carbon atoms;
⁶ is -OR ⁷ or (R ^{7 to} R ⁹ may be the same or different and represent a cation, hydrogen, or a hydrocarbon group having 1 to 6 carbon atoms), and n is an integer of 0 to 10. However, the group represented by the general formula [2] has 1 to 20 carbon atoms. ) 5. In the general formula [2], R ⁴ and R ⁵ may be the same or different from each other, and are hydrogen or a hydrocarbon group having 1 to 2 carbon atoms, and R ⁶ is —OR ⁷ (However, R
The electrolyte according to claim 4, wherein ⁷ is hydrogen or a hydrocarbon group having 1 to 6 carbon atoms, and n is an integer of 0 to 6). 6. The compound represented by the general formula [1a] or [1b], wherein R ^{1 to} R ³ are a methyl group, an ethyl group, a phenyl group, a carboxyethyl group, a methoxycarbonylethyl group, an ethoxycarbonylethyl group. The non-aqueous electrolyte according to claim 1, wherein the non-aqueous electrolyte is any one of a acryloxyethyl group, a methacryloxyethyl group, and a methoxyethyl group. 7. The compound represented by the general formula [1a] or [1b], wherein at least ^one of R ^{1 to} R ³ is a carboxyl group, a carboxymethyl group, a carboxyethyl group, a methoxycarbonylmethyl group, an ethoxy group. 2. The non-aqueous electrolyte according to claim 1, which is any one of a carbonylmethyl group, a methoxycarbonylethyl group, and an ethoxycarbonylethyl group. 8. The non-aqueous solvent comprises at least one of an isocyanuric acid derivative represented by the general formula [1a] or [1b] and a cyclic carbonate represented by the general formula [3a] or [3b]. The non-aqueous electrolyte according to any one of claims 1 to 7, comprising one and / or a chain carbonate. Embedded image (In the formula [3a] or [3b], R ^{4 to} R ⁷ may be the same or different from each other, and are a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.) 9. The method according to claim 8, wherein the cyclic carbonate represented by the general formula [2a] or [2b] is any one of ethylene carbonate, propylene carbonate, butylene carbonate, and vinylene carbonate. Non-aqueous electrolyte. 10. The non-aqueous electrolyte according to claim 9, wherein said chain carbonate is any one of dimethyl carbonate, diethyl carbonate, and methyl ethyl carbonate. 11. The non-aqueous solvent is characterized in that the isocyanuric acid derivative represented by the general formula [1a] or [1b] is contained in an amount of 0.01 to less than 5% by weight based on the whole non-aqueous solvent. The non-aqueous electrolyte according to claim 1. 12. The weight ratio of at least one cyclic carbonate represented by the general formula [2a] or [2b] to a chain carbonate in a non-aqueous solvent is 15:85.
The non-aqueous electrolyte according to claim 8, wherein the ratio is 55:45. 13. The non-aqueous electrolyte according to claim 1, wherein the electrolyte is a lithium salt. 14. A secondary battery comprising the non-aqueous electrolyte according to claim 1. 15. A negative electrode active material comprising metallic lithium, a lithium-containing alloy, a carbon material capable of doping and undoping lithium ions, tin oxide capable of doping and undoping lithium ions, and doping and undoping lithium ions. Titanium oxide or lithium ion doping
A negative electrode containing any of undoped silicon and a positive electrode active material including a transition metal oxide, a transition metal sulfide, a composite oxide of lithium and a transition metal, a conductive polymer material, a carbon material, or a mixture thereof. A lithium ion secondary battery comprising: a positive electrode including any one of the above; and the nonaqueous electrolyte according to any one of claims 1 to 14. 16. The carbon material capable of doping / dedoping lithium ions has a plane distance (d002) on the (002) plane measured by X-ray analysis of 0.340 nm or less. The lithium ion secondary battery according to claim 15.