KR20190064257A - Composition for gel polymer electrolyte, gel polymer electrolyte and lithium secondary battery comprising the same - Google Patents

Abstract

The present invention provides a composition for a gel polymer electrolyte, a gel polymer electrolyte manufactured using the same, and a lithium secondary battery. The composition for the gel polymer electrolyte comprises: an oligomer represented by chemical formula 1; an additive; a polymerization initiator; a lithium salt; and a non-aqueous solvent. The additive comprises at least one compound selected from a group consisting of an imide compound, a compound having a Si-N bond, a nitrile compound, a phosphate compound, and a boron compound. According to the present invention, the capacity of the battery can be maintained at a certain level.

Description

TECHNICAL FIELD The present invention relates to a composition for a gel polymer electrolyte, a gel polymer electrolyte prepared therefrom, and a lithium secondary battery comprising the gel polymer electrolyte. BACKGROUND ART [0002]

TECHNICAL FIELD The present invention relates to a composition for a gel polymer electrolyte, a gel polymer electrolyte prepared therefrom, and a lithium secondary battery comprising the gel polymer electrolyte. More particularly, the present invention relates to a gel polymer electrolyte composition for improving cell safety by suppressing side reactions by lithium salts, And a lithium secondary battery comprising the gel polymer electrolyte.

As technology development and demand for mobile devices are increasing, the demand for secondary batteries as energy sources is rapidly increasing. Among these secondary batteries, lithium secondary batteries having high energy density and voltage have been commercialized and widely used.

Lithium metal oxide is used as the positive electrode active material of the lithium secondary battery, and lithium metal, lithium alloy, crystalline or amorphous carbon or carbon composite material is used as the negative electrode active material. The active material is coated on the current collector with an appropriate thickness and length, or the active material itself is coated in a film form and wound or laminated together with a separator as an insulator to form an electrode assembly. The electrode assembly is then placed in a container such as a can or a pouch. To prepare a secondary battery.

Generally, the safety of a battery is improved in the order of a liquid electrolyte <gel polymer electrolyte <solid polymer electrolyte, while a cell electrolyte Is known to decrease. At present, it is known that the solid polymer electrolyte is not yet commercialized due to inferior battery performance.

A variety of non-aqueous organic solvents are used in the electrolyte. Propylene carbonate (EC) is conventionally used as a double non-aqueous organic solvent. However, it has a problem that it can cause irreversible decomposition reaction with graphite materials. In order to replace this, an ethylene / 3-component nonaqueous organic solvent including ethylene carbonate (EC) has been used. However, since ethylene carbonate has a high melting point, the use temperature is limited, and there is a problem that battery performance may be considerably deteriorated at a low temperature.

On the other hand, when moisture is contained in the lithium secondary battery, the performance of the battery may be deteriorated. In the lithium secondary battery, moisture may be contained in the active material during the manufacturing process, or may be contained in a trace amount in the electrolyte. For example, lithium titanium oxide used as an anode active material has a very low structural change during charging and discharging, is excellent in life characteristics due to a zero-strain material, forms a relatively high voltage band, Is known as a material having excellent safety and stability and has an advantage in that it can be charged rapidly in a few minutes. However, due to the property of absorbing moisture in the air, There is a problem in that when the electrode is manufactured using such a material, water contained therein is decomposed to generate a large amount of gas.

Also, the moisture present in the electrolyte can react with the electrolyte due to the potential energy provided in the charging process to generate a gas. At this time, the cell may be swollen and the reliability of the battery may deteriorate. For example, LiPF ₆ , one of the lithium salts, reacts with water to form HF, which is a strong acid, which can react spontaneously with an electrode active material exhibiting weak basicity. When the electrode active material component is eluted by the above reaction, the battery performance is deteriorated and lithium fluoride (LiF) is formed on the surface of the positive electrode, resulting in electrical resistance in the electrode, and the lifetime of the battery is lowered. Therefore, it is necessary to inhibit the formation of HF in the electrolytic solution and to prevent HF from causing a side reaction.

Korean Patent Publication No. 10-2009-0030237

Disclosure of Invention Technical Problem [8] Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to provide a gel polymer electrolyte having improved safety while suppressing the generation of HF which is an impurity generated from anions of lithium salts during charging, A gel polymer electrolyte prepared using the same, and a lithium secondary battery.

In one aspect, the present invention provides an oligomer comprising: an oligomer represented by Formula 1; additive; A polymerization initiator; Lithium salts; And a non-aqueous solvent,

Wherein the additive comprises at least one compound selected from the group consisting of an imide compound, a compound having a Si-N bond, a nitrile compound, a phosphate compound and a boron compound, and a composition for a gel polymer electrolyte .

[Chemical Formula 1]

In Formula 1,

A is a unit in which at least one fluorine is substituted or unsubstituted alkylene group having 1 to 5 carbon atoms,

B and B 'each independently represent an amide group-containing unit,

C and C 'are each independently a unit containing a (meth) acrylate group,

M is an integer of 1 to 100;

On the other hand, the imide-

And a carbodiimide compound represented by the following formula (2).

(2)

In Formula 2, R ₃ and R ₃ 'are each independently selected from the group consisting of an alkyl group having 1 to 12 carbon atoms and a cycloalkyl group having 3 to 12 carbon atoms.

The compound having the Si-N bond may include a compound represented by the following formula (3).

(3)

Wherein R ₄ is hydrogen or a silyl group in which the alkyl group having 1 to 5 carbon atoms is substituted or unsubstituted, R ₅ and R ₆ are each independently hydrogen, a substituted or unsubstituted alkyl group having 1 to 5 carbon atoms, Wherein the hetero atom is selected from the group consisting of a substituted or unsubstituted alkyl group having 1 to 5 carbon atoms and a substituted or unsubstituted silyl group having 1 to 5 carbon atoms substituted with an alkyl group having 1 to 5 carbon atoms and the heteroatom is oxygen (O), nitrogen (N) (S). &Lt; / RTI &gt;

The nitrile compound may include at least one compound selected from the group consisting of compounds represented by the following formulas (4-1) and (4-2).

[Formula 4-1]

In Formula 4-1, R ₇ is selected from the group consisting of a substituted or unsubstituted alkyl group having 1 to 5 carbon atoms and a substituted or unsubstituted alkenyl group having 1 to 5 carbon atoms.

 [Formula 4-2]

In Formula 4-2, R ₈ is selected from the group consisting of a substituted or unsubstituted alkylene group having 1 to 5 carbon atoms and a substituted or unsubstituted alkenyl group having 1 to 5 carbon atoms.

In addition, the phosphate-based compound may include at least one compound selected from the group consisting of tris (trimethylsilyl) phosphate and tris (trimethyl) phosphate.

On the other hand, the borate compound may include tris (trimethylsilyl) borate.

In addition, the oligomer of the present invention may include at least one compound selected from the group consisting of compounds represented by 1-1 to 1-6.

[Formula 1-1]

[Formula 1-2]

[Formula 1-3]

[Formula 1-4]

[Formula 1-5]

[Chemical Formula 1-6]

Each of n1 to n6 is independently an integer of 1 to 30, and m is an integer of 1 to 100.

Each of n1 to n6 is independently an integer of 1 to 30, and m is an integer of 1 to 100.

In another aspect, the present invention provides a gel polymer electrolyte prepared using the composition for gel polymer electrolyte, and a lithium secondary battery comprising the gel polymer electrolyte.

By using the composition for a gel polymer electrolyte according to the present invention, formation of HF, which is an impurity generated during formation of an electrolyte, is inhibited and the cathode active material is prevented from being eluted, so that the capacity of the battery can be maintained at a certain level or more.

Further, it is possible to realize a battery in which the performance of the battery is improved by suppressing the reaction of the HF with the electrolyte to improve the mechanical strength of the electrolyte and suppress the occurrence of side reactions.

Hereinafter, the present invention will be described in detail in order to facilitate understanding of the present invention.

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.

The terminology used herein is for the purpose of describing example implementations only and is not intended to be limiting of the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise.

In this specification, the terms "comprising," "comprising," or "having ", and the like are intended to specify the presence of stated features, But do not preclude the presence or addition of one or more other features, integers, steps, components, or combinations thereof.

In the meantime, unless otherwise specified in the present invention, "*" means the same or different atom or a connected part between the terminals of the formula.

&Lt; Gel polymer electrolyte composition >

The composition for a gel polymer electrolyte according to the present invention comprises an oligomer; additive; A polymerization initiator; Lithium salts; And non-aqueous solvents.

Oligomer

First, the oligomer will be described. The oligomer may be three-dimensionally coupled through a polymerization reaction to form a polymer network, and fluorine includes substituted or unsubstituted alkylene, amide and (meth) acrylate groups.

The lithium secondary battery can be divided into a lithium ion battery using a liquid electrolyte and a lithium polymer battery using a polymer electrolyte depending on the type of electrolyte used. Conventionally, an ion conductive liquid electrolyte in which a lithium salt or the like is dissolved in a liquid electrolyte, particularly, a non-aqueous organic solvent has been mainly used.

However, as the interest in energy storage technology becomes higher and higher, it is required to develop secondary batteries having high temperature and high voltage safety as well as being capable of charging and discharging at a small size and high capacity. Accordingly, development of a battery using a gel polymer electrolyte composed of a gel polymer rather than a liquid electrolyte has recently been attracting attention.

In general, the safety of a battery is improved in the order of liquid electrolyte < gel polymer electrolyte < solid polymer electrolyte, while battery performance is rather reduced.

That is, the gel polymer electrolyte is disadvantageous in that the conductivity of the lithium ion is lower than that of the liquid electrolyte composed of the electrolyte solution.

Accordingly, the present invention aims to solve these problems by using a gel polymer electrolyte including a polymer network formed by three-dimensionally bonding the oligomer. In the case of the gel polymer electrolyte formed by bonding the oligomer, the degree of freedom of lithium ion is increased by the anion immobilization and stabilization, and the electric resistance is reduced to realize high lithium ion conductivity. In addition, the polymer network formed of the oligomer has high heat resistance and high temperature durability, and has low volatility even at a high temperature, resulting in high electrochemical stability. Therefore, even when the lithium secondary battery is used in a high temperature environment or when the temperature inside the battery rises during driving of the battery, it is possible to control the amount of heat generation and suppress the occurrence of ignition, thereby improving the high temperature safety of the battery.

The oligomer may be represented by the following general formula (1).

[Chemical Formula 1]

In Formula 1,

Wherein A is a unit wherein at least one fluorine is substituted or unsubstituted and contains an alkylene group having 1 to 5 carbon atoms, B and B 'are each independently an amide group-containing unit, and C and C' (Meth) acrylate group, and m is an integer of 1 to 100.

On the other hand, m is preferably an integer of 1 to 50, more preferably an integer of 1 to 30. When m is within the above range, the oligomer represented by Formula 1 has an appropriate weight average molecular weight (Mw).

Herein, the weight average molecular weight in the present specification may mean a value converted to standard polystyrene measured by GPC (Gel Permeation Chromatograph), and unless otherwise specified, the molecular weight may mean a weight average molecular weight. At this time, the weight average molecular weight can be measured by Gel Permeation Chromatography (GPC). For example, after a sample of a certain concentration is prepared, the GPC measurement system alliance 4 apparatus is stabilized. When the instrument is stabilized, the standard and samples are injected into the instrument to obtain a chromatogram, and the weight average molecular weight is calculated according to the analytical method (system: Alliance 4, column: Ultrahydrogel linear x 2, eluent: 0.1M NaNO 3 7.0 phosphate buffer, flow rate: 0.1 mL / min, temp: 40, injection: 100 μL)

The weight average molecular weight (Mw) of the oligomer represented by Formula 1 may be controlled by the number of repeating units, and may be about 1,000 to 20,000, specifically 1,000 to 15,000, more specifically 1,000 to 10,000. When the weight average molecular weight of the oligomer is within the above range, the mechanical strength and volatility of the battery can be controlled, thereby suppressing the production of coarse gas and effectively improving the flame retardancy, And the like can be produced.

A is a unit containing one or more fluorine-substituted or unsubstituted alkylene groups of 1 to 5 carbon atoms. By including the unit A, the oligomer immobilizes and stabilizes the anions generated from the lithium salt, thereby increasing the degree of freedom of the lithium ion and reducing the battery resistance, thereby realizing high lithium ion conductivity.

For example, the unit A may include at least one of the units represented by the following formulas (A-1) to (A-6).

[A-1]

[A-2]

[A-3]

[A-4]

[A-5]

[A-6]

In the above formulas (A-1) to (A-6), each of n1 to n6 is independently an integer of 1 to 30. The n1 to n6 may be independently an integer of 1 to 25, more preferably an integer of 1 to 20, respectively. When each of n1 to n6 independently falls within the above range, it is possible to form an oligomer having a weight average molecular weight at a certain level and to prevent the resistance from rising.

The units B and B 'each independently contain an amide group. In the implementation of the gel polymer electrolyte using the oligomer, the ion transfer characteristic is controlled, and the function of controlling mechanical properties and adhesion is given .

For example, the units B and B 'may each independently include a unit represented by the following formula (B-1).

[Formula B-1]

In the above formula (B-1)

R ₁ is a linear or non-linear alkylene group having 1 to 10 carbon atoms, a substituted or unsubstituted cycloalkylene group having 3 to 10 carbon atoms, a substituted or unsubstituted bicycloalkylene group having 6 to 20 carbon atoms, An unsubstituted aryl group, a unit represented by the following formula: R ₁ -1, and a unit represented by the following formula: R ₁ -2.

[Chemical formula R ₁ -1]

[Chemical formula R ₁ -2]

As another example, in the above formula (B-1)

The R ₁ may include at least one of the units represented by the following formulas: R ₁ -3 to R ₁ -8.

[Chemical Formula R ₁ -3]

[Chemical Formula R ₁ -4]

[Formula R &_lt; ₁ &gt; -5]

[Chemical formula R &_lt; _{1 &}

[Chemical formula R ₁ -7]

[Chemical formula R ₁ -8]

The units C and C 'are units containing a (meth) acrylate group so that the oligomer can be bonded in a three-dimensional structure to form a polymer network. The units C and C 'may be derived from monomers comprising at least one monofunctional or multifunctional (meth) acrylate or (meth) acrylic acid in the molecular structure.

For example, the units C and C 'may each independently include at least one of the units represented by the following formulas C-1 to C-5.

[Chemical formula C-1]

[Chemical formula C-2]

[Formula C-3]

[Chemical formula C-4]

[Chemical formula C-5]

In the formulas (C-1) to (C-5), R ₂ may be independently selected from the group consisting of hydrogen and substituted or unsubstituted alkylene groups having 1 to 6 carbon atoms.

According to an embodiment of the present invention, the oligomer may include at least one compound selected from the group consisting of the following general formulas 1-1 to 1-6.

[Formula 1-1]

[Formula 1-2]

[Formula 1-3]

[Formula 1-4]

[Formula 1-5]

[Chemical Formula 1-6]

Each of n1 to n6 is independently an integer of 1 to 30, and m is an integer of 1 to 100.

On the other hand, m is preferably an integer of 1 to 50, and more preferably an integer of 1 to 30. [

On the other hand, the oligomer may be contained in an amount of 0.5 to 20 parts by weight, preferably 1.0 to 20 parts by weight, more preferably 1.5 to 20 parts by weight, based on 100 parts by weight of the composition for a gel polymer electrolyte. When the content of the oligomer is less than 0.5 part by weight, a network reaction between oligomers for forming a gel polymer electrolyte is difficult to be formed. When the oligomer content exceeds 20 parts by weight, the gel polymer electrolyte has a viscosity exceeding a certain level, Impregnation, wetting degradation and electrochemical stability may be impaired.

additive

Next, the additives will be described.

In the present invention, the additive may include at least one compound selected from the group consisting of an imide compound, a compound having Si-N bond, a nitrile compound, a phosphate compound and a boron compound.

The gel polymer electrolyte composition includes a lithium salt and a non-aqueous solvent in addition to an oligomer. In general, a fluoride-based lithium salt having a high ionic conductivity is widely used as a lithium salt. However, the anions generated by the chemical reaction of the fluoride-based lithium salts react with a trace amount of water to produce by-products such as HF, and such by-products cause decomposition of the organic solvent and electrode side reactions, have. Also, the high temperature storability of the secondary battery may be deteriorated due to the negative ions and by-products.

More specifically, for example, when LiPF ₆ is used as the lithium salt, PF ₆ ^{- which} is an anion may lose electrons on the cathode side and PF ₅ may be generated. At this time, the following chemical reactions can proceed in a cascade.

If the chain reaction proceeds, the decomposition of the organic solvent or the side reaction with the electrode may occur due to HF or other by-products generated, and the performance of the battery may be continuously deteriorated.

In order to suppress such side reactions, a method of removing water present in the electrolyte, a method of suppressing the generation of HF by using an HF scavenger, a method of stabilizing and stabilizing anions generated from a lithium salt, and the like Can be used. For example, the imide compound and the compound having the Si-N bond can fix the H ₂ O as shown in the following reaction mechanism to remove moisture in the electrode, react with the anion generated from the lithium salt in the electrolyte It is possible to suppress the generation of HF which is an impurity.

[Reaction Mechanism]

Meanwhile, the oligomer according to the present invention may be used together with an additive to form HF during the formation of the gel polymer electrolyte. The HF may collapse the polymer structure, and the electrolyte may not be properly formed. At this time, when the additives are used together, the gel polymer electrolyte can be easily formed by stabilizing anions generated by HF generation and HF. In addition, it is possible to prevent the gel polymer from being damaged by suppressing the generation of HF during the storage of the gel polymer electrolyte at room temperature, and to maintain the mechanical properties at a certain level or more.

Specifically, the imide compound may include a carbodiimide compound represented by the following formula (2).

(2)

In Formula 2, R ₃ and R ₃ 'each independently may be selected from the group consisting of an alkyl group having 1 to 12 carbon atoms and a cycloalkyl group having 3 to 12 carbon atoms.

More preferably, the imide compound is selected from the group consisting of N, N'-dicyclopentylcarbodiimide, N, N'-dicyclohexylcarbodiimide and N, N'-dicycloheptylcarbodiimide But it is not limited thereto.

In addition, the compound having Si-N bond may include a compound represented by the following general formula (3).

(3)

Wherein R ₄ is hydrogen or a silyl group in which the alkyl group having 1 to 5 carbon atoms is substituted or unsubstituted, R ₅ and R ₆ are each independently hydrogen, a substituted or unsubstituted alkyl group having 1 to 5 carbon atoms, Wherein the hetero atom is selected from the group consisting of a substituted or unsubstituted alkyl group having 1 to 5 carbon atoms and a substituted or unsubstituted silyl group having 1 to 5 carbon atoms substituted with an alkyl group having 1 to 5 carbon atoms and the heteroatom is oxygen (O), nitrogen (N) (S). &Lt; / RTI &gt;

Specifically, the compound having the Si-N system bond may be at least one compound selected from the group consisting of 1,1,1,3,3,3-hexamethyldisilazane, heptamethyldisilazane, N, N-diethylaminotrimethylsilane, N, O-tris (trimethylsilyl) hydroxyamine, and the like.

More preferably, the compound having the Si-N bond can be 1,1,1,3,3,3-hexamethyldisilazane, but is not limited thereto.

In another example, the nitrile compound can stabilize and stabilize the anion in the cell through a non-covalent electron pair in the nitrile.

Specifically, the nitrile compound may include at least one compound selected from the group consisting of compounds represented by the following formulas (4-1) and (4-2).

[Formula 4-1]

In Formula 4-1, R ₇ is selected from the group consisting of a substituted or unsubstituted alkyl group having 1 to 5 carbon atoms and a substituted or unsubstituted alkenyl group having 1 to 5 carbon atoms.

 [Formula 4-2]

In Formula 4-2, R ₈ is selected from the group consisting of a substituted or unsubstituted alkylene group having 1 to 5 carbon atoms and a substituted or unsubstituted alkenyl group having 1 to 5 carbon atoms.

Specifically, the nitrile compound is at least one compound selected from the group consisting of adiponitrile, succinonitrile, glutaronitrile, pimelonitrile, hept-3-adnitlinyl, And hex-3-enedinitrile.

More preferably, the nitrile compound may be succinonitrile, but is not limited thereto.

On the other hand, the phosphate-based compound and the boron-based compound can inhibit the generation of HF as an HF scavenger. More specifically, an anion or a by-product (for example, PF ₆ ^- or PF ₅ ) produced from the lithium salt acts as a Lewis base, and the phosphate compound and boron compound act as a Lewis acid ). At this time, the anion and the by-product may be stabilized by the Lewis acid-base reaction to inhibit the chain reaction.

Specifically, the phosphate-based compound may include at least one compound selected from the group consisting of tris (trimethylsilyl) phosphate and tris (trimethyl) phosphate.

In addition, the borate-based compound may include tris (trimethylsilyl) borate.

Meanwhile, the additive may be included in an amount of 0.1 to 30 parts by weight, preferably 0.1 to 10 parts by weight based on 100 parts by weight of the composition for a gel polymer electrolyte. When the content of the additive satisfies the above range, the polymer structure can be maintained by stabilizing the anion without impairing battery performance.

Polymerization initiator

Next, the polymerization initiator will be described.

The polymerization initiator is for polymerizing the oligomer of the present invention to form a polymer network bonded in a three-dimensional structure, and conventional polymerization initiators known in the art can be used without limitation. The polymerization initiator may be a photo polymerization initiator or a thermal polymerization initiator depending on the polymerization method.

Specifically, the photopolymerization initiator is exemplified by 2-hydroxy-2-methylpropiophenone (HMPP), 1-hydroxy-cyclohexylphenyl-ketone, benzophenone, 2- Phenyl-acetic acid, 2- [2-oxo-2-phenyl-acetoxy-ethoxy] -ethyl ester, oxy-phenyl-acetic acid 2-benzyl-2- (dimethylamino) -1- [4- (4-morpholinyl) phenyl] (2,4,6-trimethylbenzoyl) -1-butanone, 2-methyl-1- [4- (methylthio) phenyl] -2- (Bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, bis (eta 5-2,4-cyclopentadien-1-yl), bis [2,6-difluoro- Methylphenyl iodonium, hexafluorophosphate, and methylbenzoylformate, in the presence of at least one compound selected from the group consisting of 3- (1H-pyrrol-1-yl) phenyl] titanium, It may include at least one or more compounds selected from the following group:

Examples of the thermal polymerization initiator include benzoyl peroxide, acetyl peroxide, dilauryl peroxide, di-tert-butyl peroxide, t-butyl peroxy-2-ethyl-hexanoate, cumyl hydroperoxide and hydrogen peroxide, 2,2'-dicyclohexylcarbodiimide, Azobis (isobutyronitrile), azobis (2-cyanobutane), 2,2'-azobis (methylbutyronitrile), 2,2'-azobis And at least one compound selected from the group consisting of 2,2'-azobisdimethyl-valeronitrile (AMVN).

The polymerization initiator is decomposed by heat of 30 to 100 in a battery or decomposed by light such as UV at room temperature (5 to 30) to form radicals, and crosslinking is formed by free radical polymerization, So that it can be polymerized.

The polymerization initiator may be used in an amount of 0.01 to 5 parts by weight, preferably 0.05 to 5 parts by weight, more preferably 0.1 to 5 parts by weight, based on 100 parts by weight of the oligomer. When the content of the polymerization initiator is used within the above range, the amount of the unreacted polymerization initiator which may adversely affect battery performance can be minimized. When a polymerization initiator is contained within the above range, gelation can be appropriately performed.

Lithium salt

Next, the lithium salt will be described.

The lithium salt is used as an electrolyte salt in a lithium secondary battery and is used as an agent for transferring ions. Typically, the lithium salt is selected from the group consisting of LiPF ₆ , LiBF ₄ , LiSbF ₆ , LiAsF ₆ , LiClO ₄ , LiN (C ₂ F ₅ SO ₂ ) ₂ , LiN (CF ₃ SO ₂ ) ₂ , CF ₃ SO ₃ Li, LiC ₃ SO ₂ ) ₃ , LiC ₄ BO ₈ , LiTFSI, LiFSI, and LiClO ₄ , preferably LiPF ₆ , but is not limited thereto .

On the other hand, the lithium salt may be contained in the range of 0.5 to 5 M, preferably 0.5 to 5 M. When the content of the lithium salt is less than the above range, the lithium ion concentration in the electrolyte is low, The viscosity of the gel polymer electrolyte may be increased to lower the wettability of the battery, which may deteriorate battery performance.

Non-aqueous solvent

Next, the non-aqueous solvent will be described.

In the present invention, the non-aqueous solvent is, for example, ether, ester (Acetate, Propionate), amide, linear carbonate or cyclic carbonate, nitrile (acetonitrile, SN etc.) May be used alone or in combination of two or more.

Among them, a carbonate-based electrolyte solvent containing a carbonate compound, which is typically a cyclic carbonate, a linear carbonate, or a mixture thereof, may be used.

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, Carbonate, vinylene carbonate, and halides thereof, or a mixture of at least two or more thereof. Specific examples of the linear carbonate compound include dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), ethyl methyl carbonate (EMC), methyl propyl carbonate (MPC) and ethyl propyl carbonate (EPC) , Or a mixture of at least two of these compounds may be used. However, the present invention is not limited thereto.

In particular, propylene carbonate and ethylene carbonate, which are cyclic carbonates in the carbonate electrolyte solution, are highly viscous organic solvents having a high dielectric constant and can dissociate the lithium salt in the electrolytic solution well. Thus, cyclic carbonates such as ethylmethyl carbonate, diethyl carbonate Or a low viscosity, low dielectric constant linear carbonate such as dimethyl carbonate in an appropriate ratio can be used to more advantageously use an electrolytic solution having a high electrical conductivity.

Examples of the esters in the electrolyte solvent include methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate,? -Butyrolactone,? -Valerolactone,? -Caprolactone,? -Valerolactone And? -Caprolactone, or a mixture of at least two of them, but the present invention is not limited thereto.

The composition for a gel polymer electrolyte according to an embodiment of the present invention may further include other additives capable of realizing such physical properties known in the art in order to increase the efficiency of polymer network formation reaction and reduce resistance of the oligomer, , Inorganic particles, and the like.

Examples of the other additives include VC (vinylene carbonate), VEC (vinyl ethylene carbonate), PS (propane sultone), SN (succinonitrile), AdN (adiponitrile), ESa (ethylene sulfate), PRS , TMSPa (3-trimethoxysilanyl-propyl-N-aniline), TMSPi (Tris (trimethylsilyl) Phosphite), LiPO ₂ F ₂ , LiODFB (Lithium difluorooxalatoborate), LiBOB (Lithium bis- , LiBF _4, and the like.

The inorganic particles may be BaTiO ₃ , BaTiO ₃ , Pb (Zr, Ti) O ₃ (PZT), Pb _{1 -a} La _a Zr _1-b Ti _b O ₃ (PLZT, Pb (Mg _1/3 Nb _2/3 ) O ₃ -PbTiO ₃ (PMN-PT), hafnia (HfO ₂ ), SrTiO ₃ , SnO ₂ , CeO _{2 2} , MgO, NiO, CaO, ZnO, ZrO ₂ , Y ₂ O ₃ , Al ₂ O ₃ , TiO ₂ , SiC and mixtures thereof, or a mixture of at least two or more thereof .

In addition, inorganic particles having lithium ion transferring ability, that is, lithium phosphate (Li ₃ PO ₄ ), lithium titanium phosphate (Li _c Ti _d (PO ₄ ) ₃ , 0 <d <2, 0 <d <3) as phosphate _{(Li a1 Al b1 Ti c1 (} PO 4) 3, 0 <a1 <2, 0 <b1 <1, 0 <c1 <3), 14Li 2 O-9Al 2 O 3 -38TiO 2 -39P 2 O 5 like (LiAlTiP) _a2 O _b2 series glass (glass) (0 <a2 < 4, 0 <b2 <13), lithium lanthanum titanate _{(Li a3 La b3 TiO 3,} 0 <a3 <2, 0 <b3 <3) (Li _a4 Ge _b4 P _c2 S _d , 0 <a4 <4, 0 <b4 <1, 0 <c2 <1, 0 <d <5) such as Li _3.25 Ge _0.25 P _0.75 S ₄ ), Li ₃ lithium nitride such as _{N (Li a5 N b5, 0} <a5 <4, 0 <b5 <2), Li 3 PO 4 -Li 2 SiS 2 based glass, such as S-SiS ₂ (Li _a6 Si _{b6 S c3, 0 <a6 <} 3, 0 <b6 <2, 0 <c4 <4), LiI-Li 2 SP 2 S 5 P 2 S , such as ₅ series glass _{(Li a7 P b7 S c5,} 0 <a7 <3, 0 <b7 <3, 0 <c5 <7), or a mixture thereof.

&Lt; Gel polymer electrolyte &

Hereinafter, the gel polymer electrolyte according to the present invention will be described.

According to an embodiment of the present invention, the gel polymer electrolyte is prepared using the gel polymer electrolyte composition.

Conventional gel polymer electrolytes have lower ionic conductivity than liquid electrolytes and have relatively poor stability and mechanical properties when compared with solid polymer electrolytes.

However, the gel polymer electrolyte according to the present invention is characterized in that fluorine is a unit A comprising a substituted or unsubstituted alkylene group having 1 to 5 carbon atoms, units B and B 'each independently containing an amide group, By forming a polymer network with oligomers comprising units C and C 'comprising an acrylate group, ionic conductivity and mechanical properties can be improved.

In addition, since the gel polymer electrolyte composition of the present invention contains an additive, when the electrolyte is prepared from the gel polymer electrolyte composition, the formation of HF or the reaction of HF with the electrolyte can be inhibited, .

Meanwhile, the gel polymer electrolyte according to the present invention is formed by polymerizing a composition for a gel polymer electrolyte according to a conventional method known in the art. Generally, gel polymer electrolytes can be prepared by in-situ polymerization or coating polymerization.

More specifically, the in-situ polymerization includes the steps of (a) inserting an electrode assembly comprising a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode into a battery case, and (b) And injecting a composition for a gel polymer electrolyte according to the method of the present invention, followed by polymerization, to prepare a gel polymer electrolyte.

The in-situ polymerization in the lithium secondary battery can be performed by E-BEAM, gamma ray, room temperature / high temperature aging process, and may be performed through thermal polymerization or photopolymerization according to one embodiment of the present invention. The polymerization time may be about 2 minutes to 12 hours, the thermal polymerization temperature may be 30 to 100, and the photopolymerization temperature may be room temperature (5 to 30).

More specifically, an in-situ polymerization reaction in a lithium secondary battery is performed by injecting the gel polymer electrolyte composition into a battery cell, and then gelating through a polymerization reaction to form a gel polymer electrolyte.

Alternatively, the gel polymer electrolyte composition may be coated on one surface of an electrode and a separator, cured (gelled) using heat such as heat or UV, and then the electrode and / The electrode assembly may be manufactured by inserting the electrode assembly into the battery case and reusing the existing liquid electrolyte.

<Lithium secondary battery>

Next, a lithium secondary battery according to the present invention will be described. A secondary battery according to another embodiment of the present invention includes a cathode, an anode, a separator interposed between the anode and the cathode, and a gel polymer electrolyte. The gel polymer electrolyte is the same as that described above, so a detailed description thereof will be omitted.

anode

The anode may be prepared by coating a cathode mixture slurry containing a cathode active material, a binder, a conductive material, and a solvent on a cathode collector.

The positive electrode collector is not particularly limited as long as it has electrical conductivity without causing chemical change in the battery. For example, the positive electrode collector may be formed of a metal such as carbon, stainless steel, aluminum, nickel, titanium, sintered carbon, , Nickel, titanium, silver, or the like may be used.

The cathode active material is a compound capable of reversibly intercalating and deintercalating lithium, and may specifically include a lithium composite metal oxide including lithium and at least one metal such as cobalt, manganese, nickel, or aluminum have. More specifically, the lithium composite metal oxide may be at least one selected from the group consisting of lithium-manganese-based oxides (for example, LiMnO ₂ and LiMn ₂ O ₄ ), lithium-cobalt oxides (for example, LiCoO ₂ ), lithium- (for example, LiNiO ₂ and the like), lithium-nickel-manganese-based oxide (for example, LiNi _1-Y1 Mn _Y1 O ₂ (here, 0 <Y1 <1), LiMn 2-z1 Ni z1 O 4 ( here, 0 <Z1 <2) and the like), lithium-nickel-cobalt oxide (e. g., in _{LiNi 1-Y2 Co Y2 O 2} ( here, 0 <Y2 <1) and the like), lithium-manganese-cobalt oxide (e. g., LiCo _1-Y3 Mn _Y3 O ₂ (here, 0 <Y3 <1), LiMn 2-z2 Co z2 O 4 ( here, 0 <z2 <2) and the like), lithium-nickel -manganese-cobalt oxide (e.g., Ni _p1 Co _q1 Mn _r1 (Li) O ₂ (here, 0 <p1 <1, 0 <q1 <1, 0 <r1 <1, p1 + q1 + r1 = 1) or Li (Ni _p2 Co _q2 Mn _r2) O ₄ (here, 0 <p2 <2, 0 <q2 <2, 0 <r2 <2, p2 + q2 + r2 = 2) , etc.), or a lithium- nickel-cobalt-transition metal (M) oxide (e.g., Li (Ni Co _{p3 q3} Mn _r3 M _S1) O ₂ ( Wherein M is selected from the group consisting of Al, Fe, V, Cr, Ti, Ta, Mg and Mo, and p3, q3, r3 and s1 are atomic fractions of independent elements, 0 <p3 < 0 <q3 <1, 0 <r3 <1, 0 <s1 <1, p3 + q3 + r3 + s1 = 1), etc., and any one or more of these compounds may be included.

The lithium composite metal oxide may be LiCoO ₂ , LiMnO ₂ , LiNiO ₂ , lithium nickel manganese cobalt oxide (for example, Li (Ni _0.6 Mn _0.2 Co _0.2 ) O ₂ , Li (Ni _0.5 Mn _0.3 Co _0.2) O ₂ or _{Li (Ni 0.8 Mn 0.1 Co 0.1} ) O 2 ), or lithium nickel cobalt aluminum oxide _{(e.g., LiNi 0.8 Co 0.15 Al 0.05 O} 2 , etc.) or the like Considering the remarkable improvement effect according to the kind and content ratio of constituent elements forming the lithium composite metal oxide, the lithium composite metal oxide is Li (Ni _0.6 Mn _0.2 Co _0.2 ) O ₂ , _{Li (Ni 0.5 Mn 0.3 Co 0.2} ) O 2, Li (Ni 0.7 Mn 0.15 Co 0.15) O 2 or _{Li (Ni 0.8 Mn 0.1 Co 0.1} ) O 2 and the like, any one or a mixture of two or more may be used of which have.

The cathode active material may include 60 to 99% by weight, preferably 70 to 99% by weight, more preferably 80 to 98% by weight, based on the total weight of the solid material excluding the solvent in the slurry for the cathode mixture.

The binder is a component that assists in bonding of the active material to the conductive material and bonding to the current collector.

Examples of such binders include polyvinylidene fluoride, polyvinyl alcohol, carboxymethylcellulose (CMC), starch, hydroxypropylcellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene (PE) , Ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, styrene-butadiene rubber, fluorine rubber, various copolymers and the like.

Typically, the binder may include 1 to 20% by weight, preferably 1 to 15% by weight, more preferably 1 to 10% by weight, based on the total weight of the solids excluding the solvent in the slurry for the positive electrode mixture.

The conductive material is a component for further improving the conductivity of the cathode active material.

The conductive material is not particularly limited as long as it has electrical conductivity without causing chemical changes in the battery, for example, graphite; Carbon-based materials such as carbon black, acetylene black, ketjen black, channel black, furnace black, lamp black, and thermal black; Conductive fibers such as carbon fiber and metal fiber; Metal powders such as carbon fluoride, aluminum, and nickel powder; Conductive whiskey such as zinc oxide and potassium titanate; Conductive metal oxides such as titanium oxide; Conductive materials such as polyphenylene derivatives and the like can be used. Concrete examples of commercially available conductive materials include acetylene black series such as Chevron Chemical Company, Denka Singapore Private Limited, Gulf Oil Company, etc.), Ketjenblack, EC (Armak Company), Vulcan XC-72 (Cabot Company), and Super P (Timcal).

Generally, the conductive material may be contained in an amount of 1 to 20% by weight, preferably 1 to 15% by weight, more preferably 1 to 10% by weight, based on the total weight of the solid material excluding the solvent in the slurry for the positive electrode material mixture.

The solvent may include an organic solvent such as NMP (N-methyl-2-pyrrolidone), and may be used in an amount that makes it desirable to contain the cathode active material, and optionally, a binder and a conductive material . For example, such that the concentration of the solid material including the cathode active material, and optionally the binder and the conductive material is 50 to 95 wt%, preferably 70 to 95 wt%, more preferably 70 to 90 wt% .

cathode

The negative electrode may be prepared, for example, by coating a negative electrode current collector with a negative electrode mixture slurry containing a negative electrode active material, a binder, a conductive material and a solvent, or a carbon (C) electrode or metal itself as a negative electrode.

For example, when a negative electrode is manufactured by coating a negative electrode mixture slurry on the negative electrode collector, the negative electrode collector generally has a thickness of 3 to 500 μm. The negative electrode current collector is not particularly limited as long as it has high conductivity without causing chemical change in the battery. Examples of the negative electrode current collector include copper, stainless steel, aluminum, nickel, titanium, sintered carbon, copper or stainless steel Surface-treated with carbon, nickel, titanium, silver or the like, aluminum-cadmium alloy, or the like can be used. In addition, like the positive electrode collector, fine unevenness can be formed on the surface to enhance the bonding force of the negative electrode active material, and it can be used in various forms such as films, sheets, foils, nets, porous bodies, foams and nonwoven fabrics.

Examples of the negative electrode active material include natural graphite, artificial graphite, carbonaceous material; Lithium-containing titanium composite oxide (LTO), metals (Me) with Si, Sn, Li, Zn, Mg, Cd, Ce, Ni or Fe; An alloy composed of the metal (Me); An oxide of the metal (Me) (MeOx); And a composite of the metal (Me) and the carbon (C).

The negative electrode active material may include 60 to 99% by weight, preferably 70 to 99% by weight, more preferably 80 to 98% by weight based on the total weight of the solid material excluding the solvent in the negative electrode material mixture slurry.

The binder is a component that assists in bonding between the conductive material, the active material, and the current collector. Examples of such binders include polyvinylidene fluoride (PVDF), polyvinyl alcohol, carboxymethylcellulose (CMC), starch, hydroxypropylcellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene Examples thereof include ethylene, polyethylene, polypropylene, ethylene-propylene-diene polymer (EPDM), sulfonated-EPDM, styrene-butadiene rubber, fluorine rubber and various copolymers thereof.

Typically, the binder may be contained in an amount of 1 to 20% by weight, preferably 1 to 15% by weight, more preferably 1 to 10% by weight, based on the total weight of the solid material excluding the solvent in the negative electrode material mixture slurry.

The conductive material is a component for further improving the conductivity of the negative electrode active material. Such a conductive material is not particularly limited as long as it has electrical conductivity without causing chemical changes in the battery, for example, graphite such as natural graphite or artificial graphite; Carbon black such as acetylene black, ketjen black, channel black, furnace black, lamp black, and thermal black; Conductive fibers such as carbon fiber and metal fiber; Metal powders such as carbon fluoride, aluminum, and nickel powder; Conductive whiskey such as zinc oxide and potassium titanate; Conductive metal oxides such as titanium oxide; Conductive materials such as polyphenylene derivatives and the like can be used.

The conductive material may be contained in an amount of 1 to 20% by weight, preferably 1 to 15% by weight, more preferably 1 to 10% by weight based on the total weight of the solid material excluding the solvent in the slurry of the negative electrode material mixture.

The solvent may include water or an organic solvent such as NMP (N-methyl-2-pyrrolidone), and may be used in an amount that is preferred to contain the negative electrode active material, and optionally a binder and a conductive material. . For example, the concentration of the solid material including the negative electrode active material, and optionally the binder and the conductive material may be 50 wt% to 95 wt%, preferably 70 wt% to 90 wt%.

When the metal itself is used as the negative electrode, the negative electrode may be manufactured by a method of physically bonding a metal to the metal thin film itself or the negative electrode collector, followed by rolling or vapor deposition. The deposition may be performed using an electric or chemical vapor deposition method.

For example, the metal to be bonded / rolled / deposited on the metal thin film itself or on the negative electrode current collector may include lithium (Li), nickel (Ni), tin (Sn), copper (Cu), and indium Or an alloy of two kinds of metals, and the like.

Membrane

As the separator, a conventional porous polymer film conventionally used as a separator, for example, a polyolefin such as an ethylene homopolymer, a propylene homopolymer, an ethylene / butene copolymer, an ethylene / hexene copolymer, and an ethylene / methacrylate copolymer A porous polymer film made of a high molecular weight polymer may be used alone or in a laminated manner, or a nonwoven fabric made of a conventional porous nonwoven fabric such as a glass fiber having a high melting point, a 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 a cylindrical shape, a square shape, a pouch shape, a coin shape, or the like using a can.

According to another embodiment of the present invention, there is provided a battery module including the lithium secondary battery as a unit cell and a battery pack including the same. Since the battery module and the battery pack include the lithium secondary battery having a high capacity, a high rate-limiting characteristic, and a cycling characteristic, the battery module and the battery pack can be suitably used as a middle- or large- And can be used as a power source of the device.

Hereinafter, the present invention will be described more specifically by way of specific examples. However, the following examples are provided only to facilitate understanding of the present invention and are not intended to limit the scope of the present invention. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope and spirit of the present invention, and it is obvious that such variations and modifications are within the scope of the appended claims.

[Example]

1. Example 1

(1) Preparation of Composition for Gel Polymer Electrolyte

Ethylene carbonate (EC) and ethyl methyl carbonate (EMC) were mixed at a volume ratio of 3: 7, and 0.7 M of LiPF ₆ and 0.3 M of LiFSI were added to prepare a mixed solvent. 5 g of an oligomer (weight average molecular weight: 3000) having a weight average molecular weight of 3,000, 0.02 g of an ABIN initiator and 0.2 g of N, N'-dicyclohexylcarbodiimide as an additive, 0.02 g of a polymerization initiator (AIBN) g and 1 g of ESa were added to prepare a composition for a gel polymer electrolyte.

(2) Production of lithium secondary battery

94% by weight of a positive electrode active material (LiNi _1/3 Co _1/3 Mn _1/3 O ₂ ; NCM), 3% by weight of carbon black as a conductive material and 3% by weight of PVDF as a binder were dissolved in a solvent N-methyl -2-pyrrolidone (NMP) to prepare a positive electrode mixture slurry. The positive electrode material mixture slurry was applied to an aluminum (Al) thin film as a positive electrode current collector having a thickness of about 20 mu m, dried, and then rolled to produce a positive electrode.

The negative electrode mixture slurry was prepared by adding carbon powder as a negative electrode active material, PVDF as a binder and carbon black as a conductive material to 96 wt%, 3 wt% and 1 wt%, respectively, as a solvent. The negative electrode material mixture slurry was applied to a copper (Cu) thin film as an anode current collector having a thickness of 10 mu m, dried, and then rolled to produce a negative electrode.

The electrode assembly was manufactured using the separator composed of the anode, the cathode and the three layers of polypropylene / polyethylene / polypropylene (PP / PE / PP). After the composition for the gel polymer electrolyte was injected into the electrode assembly, Followed by heating at 60 DEG C for 24 hours to prepare a lithium secondary battery containing the gel polymer electrolyte.

2. Example 2

In Example 1, except that 0.5 g of 1,1,1,3,3,3-hexamethyldisilazane was added without using N, N'-dicyclohexylcarbodiimide as an additive A lithium secondary battery including a gel polymer electrolyte was prepared in the same manner as in Example 1.

3. Example 3

A gel polymer electrolyte was prepared in the same manner as in Example 1, except that 2 g of succinonitrile was added without using N, N'-dicyclohexylcarbodiimide as an additive in Example 1 A lithium secondary battery was produced.

4. Example 4

A lithium secondary battery including a gel polymer electrolyte was prepared in the same manner as in Example 1 except that 2 g of succinonitrile was further added as an additive in Example 1.

[Comparative Example]

1. Comparative Example 1

(1) Preparation of electrolyte

Ethylene carbonate (EC) and ethylmethyl carbonate (EMC) were mixed at a volume ratio of 3: 7, and 0.7 M of LiPF ₆ and 0.3 M of LiFSI were added to prepare an electrolytic solution. Other additives were prepared by adding 1.5 g of VC, 0.5 g of PS and 1 g of ESa.

(2) Production of lithium secondary battery

94% by weight of a positive electrode active material (LiNi _1/3 Co _1/3 Mn _1/3 O ₂ ; NCM), 3% by weight of carbon black as a conductive material and 3% by weight of PVDF as a binder were dissolved in a solvent N-methyl -2-pyrrolidone (NMP) to prepare a positive electrode mixture slurry. The positive electrode material mixture slurry was applied to an aluminum (Al) thin film as a positive electrode current collector having a thickness of about 20 mu m, dried, and then rolled to produce a positive electrode.

The negative electrode mixture slurry was prepared by adding carbon powder as a negative electrode active material, PVDF as a binder and carbon black as a conductive material to 96 wt%, 3 wt% and 1 wt%, respectively, as a solvent. The negative electrode material mixture slurry was applied to a copper (Cu) thin film as an anode current collector having a thickness of 10 mu m, dried, and then rolled to produce a negative electrode.

The electrode assembly was manufactured using the separator composed of the anode, the cathode and the three layers of polypropylene / polyethylene / polypropylene (PP / PE / PP), and the prepared electrolyte was injected into the electrode assembly to produce a lithium secondary battery .

2. Comparative Example 2

In the same manner as in Example 1 except that an oligomer of dipentaerythritol pentaacrylate instead of 5 g of the oligomer of the formula 1-6 was used as the oligomer in Example 1, A lithium secondary battery containing an electrolyte was prepared.

3. Comparative Example 3

A lithium secondary battery including a gel polymer electrolyte was prepared in the same manner as in Example 1, except that N, N'-dicyclohexylcarbodiimide was not used in Example 1.

[Experimental Example]

1. Experimental Example 1: Strength test of gel polymer electrolyte

The electrolyte prepared according to Examples 1 to 4 and Comparative Examples 1 to 3 was thermally cured at 65 ° C for 5 hours, and then the strength of the gel polymer electrolyte was measured. The strength of the gel polymer electrolyte was measured using a Roatainonal Rheometer. Table 1 shows the values of Example 1 as 100 and the remainder as relative values.

Strength of Gel Polymer Electrolyte Example 1 100 Example 2 99 Example 3 90 Example 4 110 Comparative Example 1 X Comparative Example 2 73 Comparative Example 3 80

Referring to Table 1, Comparative Example 1 can measure the gel strength of the liquid electrolyte only for the electrolyte containing the remaining polymer, which can not measure the gel strength. Referring to Table 1, it can be seen that the strength of the gel polymer electrolyte of the Examples is higher than those of Comparative Examples. This can prevent the gel polymer from being damaged by suppressing HF generation or stabilizing the anions and by-products that may be derived from the HF when the HF is generated, while in the case of the comparative examples, .

2. Experimental Example 2: Safety test of gel polymer electrolyte

A cylindrical bar having a diameter of 15.8 mm was placed on a battery manufactured according to Example 4 and Comparative Examples 1 to 3, and whether or not the battery was ignited by dropping a weight having a weight of 9.1 kg on a vertical plane The results are shown in Table 2, and the results are shown in Table 2.

Pass / Fail Example 4 (5/0) Comparative Example 1 (2/3) Comparative Example 2 (2/3) Comparative Example 3 (3/2)

In the case of Example 4, all of the safety tests were passed, while the comparative examples were confirmed to be failed in the safety test two to three times.

Claims (14)

An oligomer represented by the following formula (1); additive; A polymerization initiator; Lithium salts; And a non-aqueous solvent,
Wherein the additive comprises at least one compound selected from the group consisting of an imide compound, a compound having Si-N bond, a nitrile compound, a phosphate compound and a boron compound.
[Chemical Formula 1]
[Chemical Formula 1]

In Formula 1,
A is a unit in which at least one fluorine is substituted or unsubstituted alkylene group having 1 to 5 carbon atoms,
B and B 'each independently represent an amide group-containing unit,
C and C 'are each independently a unit containing a (meth) acrylate group,
M is an integer of 1 to 100;
The method according to claim 1,
The imide-
A composition for a gel polymer electrolyte comprising a carbodiimide compound represented by the following Formula 2:
(2)

In Formula 2, R ₃ and R ₃ 'are each independently selected from the group consisting of an alkyl group having 1 to 12 carbon atoms and a cycloalkyl group having 3 to 12 carbon atoms.
The method according to claim 1,
The imide compound may be at least one selected from the group consisting of N, N'-dicyclopentylcarbodiimide, N, N'-dicyclohexylcarbodiimide and N, N'-dicycloheptylcarbodiimide Wherein the electrolyte comprises a compound.
The method according to claim 1,
The compound having the Si-N system bond,
A composition for a gel polymer electrolyte comprising a compound represented by the following formula (3): &lt; EMI ID =
(3)

Wherein R ₄ is hydrogen or a silyl group in which the alkyl group having 1 to 5 carbon atoms is substituted or unsubstituted, R ₅ and R ₆ are each independently hydrogen, a substituted or unsubstituted alkyl group having 1 to 5 carbon atoms, Wherein the hetero atom is selected from the group consisting of a substituted or unsubstituted alkyl group having 1 to 5 carbon atoms and a substituted or unsubstituted silyl group having 1 to 5 carbon atoms substituted with an alkyl group having 1 to 5 carbon atoms and the heteroatom is oxygen (O), nitrogen (N) (S). &Lt; / RTI &gt;
The method according to claim 1,
The compound having the Si-N system bond may be at least one selected from the group consisting of 1,1,1,3,3,3-hexamethyldisilazane, heptamethyldisilazane, N, N-diethylaminotrimethylsilane and N, N, O -Tris (trimethylsilyl) hydroxyamine, wherein the composition comprises at least one compound selected from the group consisting of tris (trimethylsilyl) hydroxyamine.
The method according to claim 1,
The nitrile-
And at least one compound selected from the group consisting of compounds represented by the following formulas (4-1) and (4-2):
[Formula 4-1]

In Formula 4-1, R ₇ is selected from the group consisting of a substituted or unsubstituted alkyl group having 1 to 5 carbon atoms and a substituted or unsubstituted alkenyl group having 1 to 5 carbon atoms,
[Formula 4-2]

In Formula 4-2, R ₈ is selected from the group consisting of a substituted or unsubstituted alkylene group having 1 to 5 carbon atoms and a substituted or unsubstituted alkenyl group having 1 to 5 carbon atoms.
The method according to claim 1,
Wherein the nitrile compound is selected from the group consisting of adiponitrile, succinonitrile, glutaronitrile, pimelonitrile, hept-3-adnitlinyl, suveronitrile, sebaconitrile, butyronitrile, And at least one compound selected from the group consisting of 3-aminonitrile and 3-indinitrile.
The method according to claim 1,
Wherein the phosphate-based compound comprises at least one compound selected from the group consisting of tris (trimethylsilyl) phosphate and tris (trimethyl) phosphate.
The method according to claim 1,
Wherein the borate-based compound comprises tris (trimethylsilyl) borate.
The method according to claim 1,
Wherein the additive is included in an amount of 0.1 to 30 parts by weight based on 100 parts by weight of the composition for a gel polymer electrolyte.
The method according to claim 1,
Wherein the unit A comprises at least one or more units represented by the following formulas (A-1) to (A-6):
[A-1]

[A-2]

[A-3]

[A-4]

[A-5]

[A-6]

In the above formulas (A-1) to (A-6), each of n1 to n6 is independently an integer of 1 to 30.
The method according to claim 1,
Wherein the oligomer comprises at least one compound selected from the group consisting of compounds represented by the following formulas 1-1 to 1-6:
[Formula 1-1]

[Formula 1-2]

[Formula 1-3]

[Formula 1-4]

[Formula 1-5]

[Chemical Formula 1-6]

Each of n1 to n6 is independently an integer of 1 to 30, and m is an integer of 1 to 100.
A gel polymer electrolyte produced by using the gel polymer electrolyte composition of claim 1.
anode;
cathode;
A separator interposed between the anode and the cathode; And
A lithium secondary battery comprising the gel polymer electrolyte according to claim 13.