KR20120080831A - Non-aqueous electrolyte solution for lithium secondary battery and lithium secondary battery comprising the same - Google Patents

Abstract

PURPOSE: A non-aqueous electrolytic solution is provided to form more stable solid electrolyte interface membrane on an electrode surface, thereby capable of restraining decomposition on an electrode surface, and to improve charging/discharging cycle life time of a battery. CONSTITUTION: A non-aqueous electrolytic solution comprises an ionizable lithium salt, an organic solvent, and silane compound in chemical formula 1. In chemical formula 1, R1, R2, R3, R4, R5, R6, R7, and R8 is respectively hydrogen, halogen, a vinyl group, a phenyl group, a benzyl group, a mercapto group, a C1-10 alkoxy group, a C3-18 cyclic alkyl group, a C3-8 cyclic epoxyalkyl group, or a substituted or unsubstituted C1-10 branched or linear alkyl group.

Description

Non-aqueous electrolyte for lithium secondary battery and lithium secondary battery having same {NON-AQUEOUS ELECTROLYTE SOLUTION FOR LITHIUM SECONDARY BATTERY AND LITHIUM SECONDARY BATTERY COMPRISING THE SAME}

The present invention relates to a non-aqueous electrolyte lithium secondary battery and a lithium secondary battery having the same containing a silane-based additive to suppress the decomposition reaction of the electrolyte to improve the cycle life.

Recently, interest in energy storage technology is increasing. As the field of application extends to the energy of mobile phones, camcorders, notebook PCs, and even electric vehicles, the demand for high energy density of batteries used as power sources for such electronic devices is increasing. Lithium secondary batteries are the ones that can best meet these demands, and researches on them are actively under way.

Among the secondary batteries currently applied, lithium secondary batteries developed in the early 1990's include lithium salts dissolved in an appropriate amount of a negative electrode such as a carbon material capable of occluding and releasing lithium ions, a positive electrode made of lithium-containing oxide, and a mixed organic solvent. It consists of a nonaqueous electrolyte.

Recently, as the use of lithium secondary batteries expands, demand for lithium secondary batteries that can maintain excellent performance even in harsher environments such as high or low temperature environments and can be safely charged even at high voltage is increasing.

By the way, the lithium transition metal oxide or composite oxide used as a positive electrode active material of a lithium secondary battery has a structural safety and capacity determined by occlusion and release of lithium ions, and their capacity increases as the charging potential increases, but accordingly Release of transition metals and the like may also be accelerated, resulting in structural instability.

In addition, current nonaqueous electrolytes are generally prepared using carbonate-based organic solvents such as ethylene carbonate (EC) and dimethyl carbonate (DMC) as electrolyte solvents, and lithium salts such as LiPF ₆ , LiBF ₄ , and the like as electrolyte salts. .

In general, however, carbonate-based organic solvents may decompose on the surface of the electrode during charge and discharge to cause side reactions in the battery. Is co-intercalated between the graphite layers in the carbon-based negative electrode, thereby disrupting the structure of the negative electrode. Therefore, the performance of the lithium secondary battery may decrease as charging and discharging are repeated.

This is known to be solved by a solid electrolyte interface (SEI) film formed on the surface of the cathode by the reduction of a carbonate-based organic solvent during initial charging, but the SEI film known to date serves as a continuous protective film of the cathode. It is somewhat inadequate to carry out a decrease in battery capacity as the negative electrode surface reaction continues, and the life may be reduced. In addition, due to decomposition of the carbonate-based organic solvent during the formation of the SEI film, deterioration of the battery may occur due to generation of gases such as CO, CO ₂ , CH ₄ , C ₂ H ₆ , and swelling. The decomposition gas generated at this time deforms the pouch-type or can-type battery assembly, causing an internal short circuit, and in severe cases, the battery may ignite or explode. However, these side reactions can be further accelerated under high voltage conditions.

In order to solve this problem, various additives have been proposed to prevent the swelling of the battery in the nonaqueous electrolyte, and among them, compounds substituted with an electron attracting group such as fluorine have been proposed.

However, these compounds are expensive, and there is a disadvantage in that they are easily reduced at the negative electrode, which has not yet effectively solved the problem.

Accordingly, an object of the present invention is to provide a non-aqueous electrolyte lithium secondary battery and a lithium secondary battery having the same, which can suppress the decomposition reaction on the electrode surface of the electrolyte and at the same time improve the charge / discharge cycle life.

In addition, another object of the present invention is to provide a lithium secondary battery nonaqueous electrolyte excellent in the effect of suppressing the decomposition reaction of the electrolyte even under high voltage conditions and a lithium secondary battery having the same.

In order to solve the said subject, the nonaqueous electrolyte solution for lithium secondary batteries of this invention is ionizable lithium salt; Organic solvents; And a silane compound represented by Formula 1 below:

In Formula 1,

R1, R2, R3, R4, R5, R6, R7, R8 are independently of each other,

Hydrogen; halogen; Vinyl group; Allyl group; Phenyl group; Benzyl groups; Mercapto group; An alkoxy group having 1 to 10 carbon atoms; C1-C10 branched or unsubstituted or substituted with halogen, vinyl, allyl, phenyl, benzyl, mercapto, alkoxy, cyclic alkyl groups having 3 to 8 carbon atoms or cyclic epoxyalkyl groups having 3 to 8 carbon atoms Or a straight alkyl group.

In the nonaqueous electrolyte of the present invention, the silane compound is 1- (3-mercapto) propyl-3,5,7,9,1,13,15-isobutylpentacyclo-9.5.1.1 (3,9). 1 (5,15). 1 (7,13) -octasiloxane; 1-chloropropyl-3,5,7,9,1,13,15-isobutylpentacyclo-9.5.1.1 (3,9). 1 (5,15) .1 (7,13) -octasiloxane; 1- [2- (3,4-Epoxycyclohexyl) ethyl] -3,5,7,9,1,13,15-isobutylpentacyclo-9.5.1.1 (3,9) .1 (5,15 .1 (7,13) -octasiloxane; 1-vinyl-3,5,7,9,1,13,15-isobutylpentacyclo-9.5.1.1 (3,9) .1 (5,15) .1 (7,13) -octasiloxane; Or the like may be used alone or as a mixture of two or more thereof, but is not limited thereto. In addition, the silane compound may be included in an amount of 0.01 to 1 part by weight based on 100 parts by weight of the nonaqueous electrolyte.

In the non-aqueous liquid electrolyte of the present invention, the lithium salt anion is the anion is ^{F -, Cl -, Br -} , I -, NO 3 -, N (CN) 2 -, BF 4 -, ClO 4 -, PF 6 -, ^{_{(CF 3) 2 PF 4 -}} , (CF 3) 3 PF 3 -, (CF 3) 4 PF 2 -, (CF 3) 5 PF -, (CF 3) 6 P -, CF 3 SO 3 -, CF ^{_{3 CF 2 SO 3 -, (}} CF 3 SO 2) 2 N -, (FSO 2) 2 N -, CF 3 CF 2 (CF 3) 2 CO -, (CF 3 SO 2) 2 CH -, (SF 5 _{^{) 3 C -, (CF 3}} SO 2) 3 C -, CF 3 (CF 2) 7 SO 3 -, CF 3 CO 2 -, CH 3 CO 2 -, SCN ^- may be any one of ^{_{-, (CF 3 CF 2 SO}} 2) 2 N.

In the nonaqueous electrolyte solution of the present invention, the organic solvent may be used alone or in combination of two or more kinds of ethers, esters, amides, linear carbonates, and cyclic carbonates.

The nonaqueous electrolyte of the present invention can be used as an electrolyte of a lithium secondary battery in the form of a gel polymer electrolyte impregnated with a liquid electrolyte or a polymer per se.

In the nonaqueous electrolyte of the present invention, the silane compound forms a more stable SEI film on the electrode surface, thereby suppressing side reactions on the electrode surface of the electrolyte, thereby suppressing swelling of the battery and at the same time improving the charge / discharge cycle life. A lithium secondary battery can be provided. In particular, it is excellent in suppressing side reaction of electrolyte solution and improving charge and discharge cycle life under high voltage condition of 4.2V or higher.

The following drawings, which are attached to this specification, illustrate preferred embodiments of the present invention, and together with the contents of the present invention serve to further understand the technical spirit of the present invention, the present invention is limited to the matters described in such drawings. It should not be construed as limited.
1 is a graph showing the discharge capacity according to the cycle under high voltage conditions for the batteries of the examples and comparative examples of the present invention.

Hereinafter, the present invention will be described in detail with reference to the drawings. The terms and words used in the present specification and claims should not be construed as limited to ordinary or dictionary terms and the inventor may appropriately define the concept of the term in order to best describe its invention It should be construed as meaning and concept consistent with the technical idea of the present invention.

Non-aqueous electrolyte solution for lithium secondary batteries of the present invention, the ionizable lithium salts; Organic solvents; And a silane compound represented by Formula 1 below.

[Formula 1]

R1, R2, R3, R4, R5, R6, R7, R8 are, independently from each other, hydrogen; halogen; Vinyl group; Allyl group; Phenyl group; Benzyl groups; Mercapto group; An alkoxy group having 1 to 10 carbon atoms; C1-C10 branched or unsubstituted or substituted with halogen, vinyl, allyl, phenyl, benzyl, mercapto, alkoxy, cyclic alkyl groups having 3 to 8 carbon atoms or cyclic epoxyalkyl groups having 3 to 8 carbon atoms Or a straight alkyl group.

In Formula 1, the position at which the halogen, vinyl group, allyl group, phenyl group, benzyl group, mercapto group, alkoxy group or cyclic alkyl group having 3 to 8 carbon atoms is substituted is not particularly limited. Thus, it may be the middle portion or the terminal portion of a branched or straight chain alkyl chain.

As described above, the SEI film on the negative electrode surface of the lithium secondary battery plays a major role in preventing side reactions of the electrolyte. However, the SEI film formed of an organic solvent or additive known to date has a problem in that it is difficult to maintain continuous performance.

However, the silane compound according to the present invention participates in the formation of the SEI film and contributes to the stabilization of the film to solve the above problem. It is determined that various functional groups, such as mercapto groups, among the silane compounds according to the present invention are adsorbed on the surface of the electrode to contribute to the formation of the SEI film, but this is only an estimation and the scope of the present invention is not limited thereto. In addition, in the silane compound according to the present invention, the silane also participates in SEI film formation and contributes to the improvement of high temperature performance.

In particular, the silane compound of the present invention has a cage structure, which provides a large number of sites to which lithium ions can bind, thereby making the movement of lithium ions smoother, thereby improving cycle life and other fundamentals of batteries. Although it is determined that the performance is improved, the scope of the present invention is not limited thereto.

That is, the use of the silane compound according to the present invention enables the formation of a stabilized SEI film, thereby improving the side reaction prevention effect and cycle life of the electrolyte. In particular, even in a high voltage system of 4.2 V or more in which the decomposition reaction of the electrolyte is further activated, the nonaqueous electrolyte containing the silane compound of the present invention exhibits an excellent effect of inhibiting the decomposition reaction of the electrolyte and improving the cycle life.

Specific examples of the silane compound represented by Formula 1 include 1- (3-mercapto) propyl-3,5,7,9,1,13,15-isobutylpentacyclo-9.5.1.1 (3,9) .1 (5,15) .1 (7,13) -octasiloxane; 1-chloropropyl-3,5,7,9,1,13,15-isobutylpentacyclo-9.5.1.1 (3,9). 1 (5,15) .1 (7,13) -octasiloxane; 1- [2- (3,4-Epoxycyclohexyl) ethyl] -3,5,7,9,1,13,15-isobutylpentacyclo-9.5.1.1 (3,9) .1 (5,15 .1 (7,13) -octasiloxane; And 1-vinyl-3,5,7,9,1,13,15-isobutylpentacyclo-9.5.1.1 (3,9) .1 (5,15) .1 (7,13) -octasiloxane It may be any one selected from the group consisting of or a mixture of two or more thereof, but is not limited thereto.

The silane compound according to the present invention is preferably included in 0.01 to 1 parts by weight relative to 100 parts by weight of the nonaqueous electrolyte. If the content is less than 0.01 parts by weight of the SEI membrane surface may not be sufficient to inhibit the decomposition of the electrolyte organic solvent, and if more than 1 part by weight may exceed the solubility in the general electrolyte solution, some of the silane compound that is not dissolved in the battery resistance It may also cause an increase. In this aspect, the silane compound according to the present invention may be included in the non-aqueous electrolyte more preferably 0.05 parts by weight to 1 part by weight, most preferably 0.1 parts by weight to 1 parts by weight.

The lithium salt contained as an electrolyte in a non-aqueous liquid electrolyte of the present invention can be used without limitation, those which are commonly used in a lithium secondary battery electrolyte, such as the lithium salt, the anion is F ^-, Cl ^-, Br ^-, I ^{-, _{NO 3 -, N (CN)}} 2 -, BF 4 -, ClO 4 -, PF 6 -, (CF 3) 2 PF 4 -, (CF 3) 3 PF 3 -, (CF 3) 4 PF 2 -, ^{_{(CF 3) 5 PF -,}} (CF 3) 6 P -, CF 3 SO 3 -, CF 3 CF 2 SO 3 -, (CF 3 SO 2) 2 N -, (FSO 2) 2 N -, CF 3 _{CF 2 (CF 3) 2 CO} -, (CF 3 SO 2) 2 CH -, (SF 5) 3 C -, (CF 3 SO 2) 3 C -, CF 3 (CF 2) 7 SO 3 -, CF _{^{3 CO 2 -, CH 3 CO}} 2 -, SCN ^- and (CF ₃ CF ₂ SO ₂ ) ₂ N ^- .

As the organic solvent included in the nonaqueous electrolyte of the present invention described above, those conventionally used in the lithium secondary battery electrolyte may be used without limitation, and for example, ethers, esters, amides, linear carbonates, cyclic carbonates, and the like may be used alone or independently. It can mix and use 2 or more types.

Among them, a carbonate compound which is typically a cyclic carbonate, a linear carbonate, or a mixture thereof may be included. Specific examples of the cyclic carbonate compound include ethylene carbonate (EC), propylene carbonate (PC), 1,2-butylene carbonate, 2,3-butylene carbonate, 1,2-pentylene carbonate, 2,3-pentylene carbonate, vinylene carbonate, and any one selected from the group consisting of halides thereof or mixtures of two or more thereof. Specific examples of the linear carbonate compounds include dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate, ethylmethyl carbonate (EMC), methylpropyl carbonate and ethylpropyl carbonate. Any one selected or a mixture of two or more thereof may be representatively used, but is not limited thereto.

In particular, ethylene carbonate and propylene carbonate, which are cyclic carbonates among the carbonate-based organic solvents, are highly viscous organic solvents, and thus may be preferably used because they dissociate lithium salts in the electrolyte well, such as dimethyl carbonate and diethyl carbonate. When the same low viscosity, low dielectric constant linear carbonate is mixed and used in an appropriate ratio, an electrolyte having high electrical conductivity can be made, and thus it can be used more preferably.

As the ether in the organic solvent, any one selected from the group consisting of dimethyl ether, diethyl ether, dipropyl ether, methyl ethyl ether, methyl propyl ether and ethyl propyl ether or a mixture of two or more thereof may be used , But is not limited thereto.

Examples of the ester in the organic solvent include methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate,? -Butyrolactone,? -Valerolactone,? -Caprolactone,? -Valerolactone, ε-caprolactone, or a mixture of two or more thereof, but the present invention is not limited thereto.

The non-aqueous electrolyte solution for a lithium secondary battery of the present invention described above is manufactured into a lithium secondary battery by injecting an electrode structure composed of a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode. As the positive electrode, the negative electrode, and the separator constituting the electrode structure, all those conventionally used for manufacturing a lithium secondary battery may be used.

As a specific example, a lithium-containing transition metal oxide may be preferably used as the cathode active material. For example, Li _x CoO ₂ (0.5 <x <1.3), Li _x NiO ₂ (0.5 <x <1.3), and Li _x MnO ₂ (0.5 <x <1.3), Li _x Mn ₂ O ₄ (0.5 <x <1.3), Li _x (Ni _a Co _b Mn _c ) O ₂ (0.5 <x <1.3, 0 <a <1, 0 < b <1, 0 <c <1, a + b + c = 1), Li _x Ni _{1 -y} Co _y O ₂ (0.5 <x <1.3, 0 <y <1), Li _x Co _{1 -y} Mn _y O ₂ (0.5 <x <1.3, 0 ≦ y <1), Li _x Ni _{1- y} Mn _y O ₂ (0.5 <x <1.3, O ≦ y <1), Li _x (Ni _a Co _b Mn _c ) O ₄ (0.5 <x <1.3, 0 <a <2, 0 <b <2, 0 <c <2, a + b + c = 2), Li _x Mn _{2 -z} Ni _z O ₄ (0.5 < x <1.3, 0 <z <2), Li _x Mn _{2 -z} Co _z O ₄ (0.5 <x <1.3, 0 <z <2), Li _x CoPO ₄ (0.5 <x <1.3) and Li _x FePO ₄ (0.5 <x <1.3) may be used any one selected from the group consisting of or a mixture of two or more thereof, and the lithium-containing transition metal oxide may be coated with a metal or metal oxide such as aluminum (Al). . In addition to the lithium-containing transition metal oxide, sulfide, selenide, halide, and the like may also be used.

As the negative electrode active material, a carbon material, lithium metal, silicon, tin, or the like, which can normally occlude and release lithium ions, may be used, and a metal oxide such as TiO ₂ and SnO ₂ having a potential of less than ₂ V may be used. Preferably, a carbon material may be used, and as the carbon material, both low crystalline carbon and high crystalline carbon may be used. Soft crystalline carbon and hard carbon are typical low crystalline carbon, and high crystalline carbon is natural graphite, Kish graphite, pyrolytic carbon, liquid crystal pitch-based carbon fiber. High temperature calcined carbon such as (mesophase pitch based carbon fiber), meso-carbon microbeads, Mesophase pitches and petroleum or coal tar pitch derived cokes.

The positive electrode and / or the negative electrode may include a binder, and the binder may include vinylidene fluoride-hexafluoropropylene copolymer (PVDF-co-HFP), polyvinylidenefluoride, polyacrylonitrile ), Various types of binder polymers such as polymethylmethacrylate may be used.

In addition, as the separator, conventional porous polymer films conventionally used as separators, for example, polyolefins such as ethylene homopolymer, propylene homopolymer, ethylene / butene copolymer, ethylene / hexene copolymer and ethylene / methacrylate copolymer, etc. The porous polymer film made of the polymer may be used alone or by laminating them, or a conventional porous nonwoven fabric, for example, a non-woven fabric made of high melting point glass fiber, polyethylene terephthalate fiber, or the like may be used. It is not.

The external shape of the lithium secondary battery of the present invention is not particularly limited, but may be cylindrical, square, pouch type, or coin type using a can.

Hereinafter, the present invention will be described in detail with reference to Examples. However, the embodiments according to the present invention can be modified into various other forms, and the scope of the present invention should not be construed as being limited to the embodiments described below. The embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art.

Example  One

<Production of Nonaqueous Electrolyte>

Ethylene carbonate: Ethyl methyl carbonate = 1 M LiPF ₆ solution having a composition of 1: 2 (volume ratio) was used as the electrolyte, 1-vinyl-3,5,7,9,1,13,15- with respect to 100 parts by weight of the electrolyte 0.1 part by weight of isobutylpentacyclo-9.5.1.1 (3,9) .1 (5,15) .1 (7,13) -octasiloxane was added.

<Manufacture of battery>

A positive electrode slurry was prepared by mixing LiCoO ₂ as a positive electrode active material, polyvinylidene fluoride (PVdF) as a binder, and carbon at a weight ratio of 93: 4: 4 with a conductive material, and then dispersing it in N-methyl-2-pyrrolidone. The slurry was coated on an aluminum current collector and then dried and rolled to prepare a positive electrode.

Further, natural graphite as a negative electrode active material, styrene-butadiene rubber as a binder and carboxymethyl cellulose as a thickener are mixed in a weight ratio of 96: 2: 2, and then dispersed in water to prepare a negative electrode slurry, and the slurry is coated on a copper current collector. After coating, it was dried and rolled to prepare a negative electrode.

Thereafter, a coin-type battery was manufactured by the conventional method using the prepared positive electrode and the negative electrode together with the PE separator, followed by pouring the electrolyte solution to complete the battery manufacturing.

Example  2

, R8: -(CH₂)₃-SH) 0.1 중량부를 사용한 것을 제외하고는, 실시예 1과 동일한 방법으로 비수전해액 및 전지를 제조하였다.1- (3-mercapto) propyl-3,5,7,9,1,13,15-isobutylpentacyclo-9.5.1.1 (3,9) .1 (5,15) .1 ( 7,13) -octasiloxane (In Formula 1, R1-R7:

, R8:-(CH ₂ ) ₃ -SH) A non-aqueous electrolyte and a battery were prepared in the same manner as in Example 1, except that 0.1 part by weight was used.

Example  3

1- [2- (3,4-epoxycyclohexyl) ethyl] -3,5,7,9,1,13,15-isobutylpentacyclo-9.5.1.1 (3,9) .1 ( 5,15). A non-aqueous electrolyte and a battery were prepared in the same manner as in Example 1, except that 0.1 part by weight of 1 (7,13) -octasiloxane was used.

Example  4

1-chloropropyl-3,5,7,9,1,13,15-isobutylpentacyclo-9.5.1.1 (3,9) .1 (5,15) .1 (7,13)-as silane compound A nonaqueous electrolyte and a battery were prepared in the same manner as in Example 1, except that 0.1 part by weight of octasiloxane was used.

Comparative example

An electrolyte solution and a battery were manufactured in the same manner as in Example 1, except that the silane compound was not added.

Test Example : Under high voltage Charging and discharging  Cycle life measurement

The coin-type battery manufactured in Examples and Comparative Examples was subjected to a charge and discharge cycle test under 0.5C charge and 0.5C discharge conditions based on the 4.35V to 3.0V cut off voltage range, and the results are shown in FIG. 1.

As shown in FIG. 1, the examples in which the silane compound was added according to the present invention had a decrease in capacity even when the cycle was increased even under high voltage, resulting in a significantly improved cycle life compared to the comparative example without the addition of the silane compound. Can be.

Claims (10)

Ionizable lithium salts;
Organic solvents; And
A nonaqueous electrolyte solution for a lithium secondary battery comprising a silane compound represented by Formula 1 below:
[Formula 1]

In Chemical Formula 1,
R1, R2, R3, R4, R5, R6, R7, R8 are, independently from each other, hydrogen; halogen; Vinyl group; Allyl group; Phenyl group; Benzyl groups; Mercapto group; An alkoxy group having 1 to 10 carbon atoms; C1-C10 branched or unsubstituted or substituted with halogen, vinyl, allyl, phenyl, benzyl, mercapto, alkoxy, cyclic alkyl groups having 3 to 8 carbon atoms or cyclic epoxyalkyl groups having 3 to 8 carbon atoms Or a straight alkyl group. The method of claim 1,
The silane compound is 1- (3-mercapto) propyl-3,5,7,9,1,13,15-isobutylpentacyclo-9.5.1.1 (3,9) .1 (5,15) .1 (7,13) -octasiloxane; 1-chloropropyl-3,5,7,9,1,13,15-isobutylpentacyclo-9.5.1.1 (3,9). 1 (5,15) .1 (7,13) -octasiloxane; 1- [2- (3,4-Epoxycyclohexyl) ethyl] -3,5,7,9,1,13,15-isobutylpentacyclo-9.5.1.1 (3,9) .1 (5,15 .1 (7,13) -octasiloxane; And 1-vinyl-3,5,7,9,1,13,15-isobutylpentacyclo-9.5.1.1 (3,9) .1 (5,15) .1 (7,13) -octasiloxane Non-aqueous electrolyte solution for lithium secondary batteries, characterized in that any one or a mixture of two or more selected from the group consisting of. The method of claim 1,
The silane compound is a non-aqueous electrolyte lithium secondary battery, characterized in that it comprises 0.01 to 1 part by weight relative to 100 parts by weight of the non-aqueous electrolyte. The method of claim 1,
The lithium salt of the anion is ^{F -, Cl -, Br -} , I -, NO 3 -, N (CN) 2 -, BF 4 -, ClO 4 -, PF 6 -, (CF 3) 2 PF 4 -, ( ^{_{CF 3) 3 PF 3 -,}} (CF 3) 4 PF 2 -, (CF 3) 5 PF -, (CF 3) 6 P -, CF 3 SO 3 -, CF 3 CF 2 SO 3 -, (CF 3 ^{_{SO 2) 2 N -, (}} FSO 2) 2 N -, CF 3 CF 2 (CF 3) 2 CO -, (CF 3 SO 2) 2 CH -, (SF 5) 3 C -, (CF 3 SO 2 _{^{) 3 C -, CF 3 (}} CF 2) 7 SO 3 -, CF 3 CO 2 -, CH 3 CO 2 -, SCN ^- and (CF ₃ CF ₂ SO ₂ ) ₂ N ^-Non- aqueous electrolyte solution for a lithium secondary battery, characterized in that any one selected from the group consisting of. The method of claim 1,
The organic solvent is any one selected from the group consisting of ethers, esters, amides, linear carbonates and cyclic carbonates, or a mixture of two or more thereof. The method of claim 5,
The cyclic carbonates are ethylene carbonate, propylene carbonate, 1,2-butylene carbonate, 2,3-butylene carbonate, 1,2-pentylene carbonate, 2,3-pentylene carbonate, vinylene carbonate and their halides Non-aqueous electrolyte solution for a lithium secondary battery comprising any one selected from the group consisting of or a mixture of two or more thereof. The method of claim 5,
The linear carbonate is lithium secondary, characterized in that it contains any one or a mixture of two or more selected from the group consisting of dimethyl carbonate, diethyl carbonate, dipropyl carbonate, ethylmethyl carbonate, methylpropyl carbonate and ethylpropyl carbonate Non-aqueous electrolyte solution for batteries. The method of claim 5,
The ether is any one selected from the group consisting of dimethyl ether, diethyl ether, dipropyl ether, methylethyl ether, methylpropyl ether and ethylpropyl ether, or a mixture of two or more thereof. Nonaqueous electrolyte. The method of claim 5,
The esters are methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, γ-butyrolactone, γ-valerolactone, γ-caprolactone, σ-valerolactone and ε-caprolactone Non-aqueous electrolyte solution for lithium secondary batteries comprising any one selected from the group consisting of or a mixture of two or more thereof. In a lithium secondary battery comprising a negative electrode, a positive electrode and a nonaqueous electrolyte,
The nonaqueous electrolyte is a lithium secondary battery, characterized in that the nonaqueous electrolyte for lithium secondary battery of any one of claims 1 to 9.

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