KR101669218B1 - Gel polymer electrolyte, Lithium battery comprising gel polymer electrolyte, method for preparing gel polymer electrolyte, and method for preparing lithium battery - Google Patents

Abstract

A first lithium salt; Organic solvent; Fluorine compounds; And

There is provided a gel polymer electrolyte comprising a polymer obtained by polymerizing a monomer represented by the following Formula 1:

≪ Formula 1 >

H ₂ C = C- (OR) _n -OCH = CH ₂

In the above formula, R is an alkylene group having 2 to 10 carbon atoms, and n is 1 to 1000.

Gel polymer electrolyte

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gel polymer electrolyte, a lithium battery including the same, a method of preparing a gel polymer electrolyte, and a method of preparing a lithium battery,

Gel polymer electrolyte, a lithium battery including the same, a method of producing a gel polymer electrolyte, and a method of manufacturing a lithium battery.

Flexible electronic devices, such as electronic paper, have become the subject of much interest as next generation products. A secondary battery can be used as an energy source for such flexible electronic devices. Secondary cells used in flexible electronics should be flexible and free of electrolyte leakage problems. Therefore, it is preferable to use a polymer electrolyte.

A thin film process and a printing process of a vapor deposition type can be used for manufacturing the flexible electronic device. The printing method is suitable because the deposition method is complicated and the manufacturing cost is high. Therefore, it is preferable that the secondary battery is manufactured by the printing method, and the polymer electrolyte included in the secondary battery is also preferably manufactured by the printing method.

Conventional polymer electrolytes are prepared by irradiating ultraviolet rays, electron beams, or heat to an electrolyte solution obtained by mixing a monomer and an initiator to cure or thermally cure the electrolyte. These methods require a separate curing device and are difficult to apply to the printing method.

Therefore, there is a need for a method of producing a polymer electrolyte applicable to a printing system without a separate curing apparatus.

One aspect is to provide a new gel polymer electrolyte.

And another aspect thereof is to provide a lithium battery including the gel polymer electrolyte.

Another aspect provides a method for producing the gel polymer electrolyte.

Another aspect provides a method for producing the lithium battery.

On one side

A first lithium salt; Organic solvent; Fluorine compounds; And

There is provided a gel polymer electrolyte comprising a polymer obtained by polymerizing a monomer represented by the following formula 1:

≪ Formula 1 >

H ₂ C = C- (OR) _n -OCH = CH ₂

In the above formula, R is an alkylene group having 2 to 10 carbon atoms, and n is 1 to 1000.

Anodic according to another aspect; cathode; And a lithium polymer battery comprising the gel polymer electrolyte.

According to another aspect,

Preparing a first solution containing a fluorine compound and an organic solvent, and a second solution containing a monomer and an organic solvent of the following formula 1, respectively; And

Mixing the first solution and the second solution,

Wherein the first solution or the second solution further comprises a first lithium salt, the method comprising:

≪ Formula 1 >

H ₂ C = C- (OR) _n -OCH = CH ₂

In the above formula, R is an alkylene group having 2 to 10 carbon atoms, and n is 2 to 1000.

According to another aspect,

Preparing a first solution containing an electrode, a fluorine compound and an organic solvent, and a second solution containing a monomer and an organic solvent of the following formula 1, respectively; And

And coating or printing the first solution and the second solution on the electrode to form a gel polyelectrolyte,

Wherein the gel polymer electrolyte further comprises a first lithium salt.

≪ Formula 1 >

H ₂ C = C- (OR) _n -OCH = CH ₂

In the above formula, R is an alkylene group having 2 to 10 carbon atoms, and n is 2 to 1000.

According to one aspect, by mixing a fluorine compound capable of producing protonic acid or Lewis acid with a monomer containing a vinyl group by reacting with residual water in the electrolyte, A gel polymer electrolyte is prepared, and a lithium battery including the polymer electrolyte is improved in charge / discharge characteristics such as initial efficiency, capacity retention rate, and the like.

Hereinafter, a gel polymer electrolyte according to exemplary embodiments, a lithium battery including the same, a method for manufacturing a gel polymer electrolyte, and a method for manufacturing a lithium battery will be described in detail.

The gel polymer electrolyte according to an embodiment includes a polymer produced by polymerizing a first lithium salt, an organic solvent, a fluorine compound, and a monomer represented by Formula 1 below:

≪ Formula 1 >

H ₂ C = C- (OR) _n -OCH = CH ₂

In the above formula, R is an alkylene group having 2 to 10 carbon atoms, and n is 1 to 1000.

The fluorine compound reacts with the residual moisture in the organic solvent to produce protonic acid or Lewis acid. The first lithium salt reacts with residual moisture in the organic solvent to form protonic acid or Lewis acid . That is, the first lithium salt is inert to the remaining water.

The process in which the monomer of Formula 1 is polymerized to produce a polymer is, for example, as follows. First, a trace amount of residual moisture in the organic solvent is reacted with the fluorine compound to form protonic acid or Lewis acid. The produced protonic acid or Lewis acid serves as a polymerization initiator for initiating cationic polymerization by activating the carbanion ion of the monomer of the formula (1). Whereby the crosslinked polyvinyl ether polymer is produced by the cationic polymerization. By including two functional groups in the monomer of Formula 1, various crosslinking reactions can proceed to form a matrix of the polyvinyl ether polymer.

The polyvinyl ether-based polymer may include an electrolyte solution containing a first lithium salt, an organic solvent, and a fluorine compound before being fully cured in the polymerization process. As a result, an electrolyte containing the first lithium salt, the organic solvent, and the fluorine compound is impregnated into the polymer, and a gel electrolyte polymer electrolyte can be obtained.

Since the gel electrolyte can serve as a structural support for suppressing the irreversible reaction between the negative electrode active material and the electrolyte and maintaining the structure of the active material and the electrode at the time of charge / discharge, the lithium polymer battery employing the gel polymer electrolyte Charge and discharge characteristics can be improved.

However, if the polymerization reaction of the monomer of formula (1) proceeds rapidly and the polymer is completely cured before impregnation with the organic solvent, the organic solvent can not be impregnated into the polymer. As a result, the cured polymer is separated from the organic solvent. For example, when the separated polymer is attached to the surface of the electrode, the contact between the organic solvent and the surface of the electrode is interrupted, and the electrode reaction becomes impossible.

Since the gel polymer electrolyte is formed by the reaction of a protonic acid or a Lewis acid generated from a fluorine compound with a monomer, a separate curing device or initiator is not required. Further, the rate of polymerization of the monomer can be controlled by controlling the content and / or the kind of the fluorine compound.

The polymerization of the monomer of Formula 1 may be carried out at room temperature. The ambient temperature may range, for example, from a temperature above which the lithium salt precipitates to a temperature below the boiling point of the organic solvent. For example, from 10 to 40 캜.

The fluorine compound capable of producing the protonic acid or the Lewis acid in the gel polymer electrolyte according to another embodiment may be, for example, a fluorinated organic compound, a second lithium salt containing fluorine, or a mixture thereof.

The fluorinated organic compound may be at least one compound selected from the group consisting of the following general formulas (2) to (8), but is not limited thereto. Any fluorinated organic compound capable of reacting with residual moisture in the electrolyte to produce protonic acid or Lewis acid Can be used.

&Lt; Formula 2 > < EMI ID =

&Lt; Formula 6 > < EMI ID =

In the above formulas, R ₁ to R ₃ independently represent hydrogen or an alkyl group having 1 to 10 carbon atoms which is substituted or unsubstituted with a fluorine atom, and R ₄ to R ₉ independently represent a fluorine atom, Alkyl group having 1 to 10 carbon atoms, and at least one of R ₄ to R ₉ is a fluorine atom.

The second lithium salt containing fluorine may be LiBF ₄ , LiPF ₆ , LiAsF ₆ , LiSbF ₆ , LiPF ₃ (CF ₂ CF ₃ ) ₃ , or a mixture thereof, but is not limited thereto. Can be used to form a protonic acid or a Lewis acid.

However, for example, when the second lithium salt containing fluorine is contained at a high concentration in the electrolytic solution, the amount of the protonic acid or Lewis acid generated by the reaction of the second lithium salt containing fluorine with the residual water in the organic solvent Can be rapidly increased. Therefore, the rate of the polymerization reaction initiated by the protonic acid or Lewis acid can be rapidly increased. As a result, the instant polymerization reaction proceeds instantaneously when the second lithium salt containing fluorine is mixed with the monomer, so that a fully cured polymer containing only the repeating unit of the monomer is formed and can be separated from the electrolyte solution.

The first lithium salt _{LiCF 3 CO 2, LiN (COCF} 3) 2, LiN (COCF 2 CF 3) 2, LiCF 3 SO 3, LiCF 3 CF 2 SO 3, LiC 4 F 9 SO 3, LiN (CF 3 SO ₂ ) ₂ , LiN (C ₂ F ₅ SO ₂ ) ₂ , LiN (C _p F _{2p + 1} SO ₂ ) (C _q F _{2q + 1} SO ₂ ) where p and q are integers, lithium difluoro Lithium bis (oxalato) borate, Lithium bis (oxalato) borate, Lithium difluoro (oxalato) borate, LiFOB, Lithium bis (oxalato) borate, Lithium bis (oxalato) borate, Lithium (malonato oxalato) borate, LiMOB), or a mixture thereof, but is not limited thereto. Any lithium salt that does not generate protonic acid or hydrofluoric acid by reacting with residual moisture in the electrolytic solution can be used.

That is, the first lithium salt is a lithium salt that does not contain fluorine or does not generate protonic acid or Lewis acid even if it contains fluorine. For example, a fluoride atom is a lithium salt that is connected to a carbon atom and does not react with water. On the other hand, the fluorine-containing second lithium salt is a lithium salt which reacts with water to form a protonic acid or a Lewis acid.

The content of the fluorine compound in the gel polymer electrolyte may be 0.1 to 30% by weight based on the total weight of the gel polymer electrolyte. For example, the content of the fluorine compound may be 0.5 to 20 wt% of the total weight of the gel polymer electrolyte. That is, the fluorine compound content range is suitable for a gel polymer electrolyte including a polymer in a gel state.

The content of the polymer in the gel polymer electrolyte may be 0.1 to 30 wt% of the total weight of the gel polymer electrolyte. That is, the polymer content range is suitable for a gel polymer electrolyte including a polymer in a gel state. For example, the content of the polymer may be 0.5 to 20 wt% of the total weight of the electrolyte. However, if the charging and discharging characteristics of the lithium battery including the gel polymer electrolyte can be improved, it is also possible that the polymer is used outside the above range.

The concentration of the first lithium salt that does not generate the protonic acid or the Lewis acid in the gel polymer electrolyte may be 0.01 to 2.0 M. The above range of concentration is suitable for the production of a gel polymer electrolyte including a gel-state polymer. However, it is also possible that the concentration of the first lithium salt which does not generate the propionic acid or Lewis acid is outside the range of 0.5 to 2M.

In the gel polymer electrolyte, the organic solvent may be a high-k solvent, a low boiling solvent, or a mixture thereof. The high-dielectric solvent is suitable for the gel polymer electrolyte having a dielectric constant of 30 to 100 and the low boiling point solvent is suitable for the gel polymer electrolyte having a boiling point of 77 to 150 ° C. However, the solvent is not necessarily limited to these, Any organic solvent that can be used is possible.

The high-dielectric-constant solvent is not particularly limited as long as it is commonly used in the art, and examples thereof include cyclic carbonates such as ethylene carbonate, ethylene carbonate, propylene carbonate and butylene carbonate, gamma-butyrolactone and / A mixture thereof and the like may be used.

The low boiling point solvent is not particularly limited as long as it is commonly used in the art, and examples thereof include dimethyl carbonate, ethyl methyl carbonate, Chain carbonates such as diethyl carbonate, dipropyl carbonate, dimethoxyethane, diethoxyethane, fatty acid ester derivatives and / or mixtures thereof may be used.

In the mixed solvent in which the high-permittivity solvent and the low-boiling solvent are mixed, the ratio of the high-boiling solvent to the low-boiling solvent is preferably 1: 1 to 1: 9. The above range is suitable in terms of discharge capacity and charge / discharge life, but may be used outside the above range.

A lithium battery according to another embodiment includes a cathode; Anode; And the above gel polymer electrolyte. The lithium battery can be manufactured, for example, as follows.

First, a positive electrode plate is prepared.

A cathode active material, a conductive agent, a binder and a solvent are mixed to prepare a cathode active material composition. The positive electrode active material composition is coated and dried directly on the aluminum current collector to prepare a positive electrode plate or the positive electrode active material composition is cast on a separate support and then the film obtained by peeling from the support is laminated on the aluminum current collector Whereby a positive electrode plate can be manufactured. Alternatively, the positive electrode active material composition may be prepared in the form of an electrode ink containing an excessive amount of solvent, and printed on a support by an ink jet method or a gravure printing method to produce a positive electrode plate. The printing method is not limited to the above method, and any method that can be used for general coating and printing can be used.

The cathode active material used for the cathode is a lithium-containing metal oxide, and any of those conventionally used in the art can be used without limitation. For example, LiCoO ₂ , LiMn _x O _2x (x = 1, 2), LiNi _1-x Mn _x O _2x (0 <x <1), Ni _1-xy Co _x Mn _y O ₂ 0.5, and 0≤y≤0.5), LiFePO ₄ or the like.

As the conductive agent, carbon black may be used. Examples of the binder include vinylidene fluoride / hexafluoropropylene copolymer, polyvinylidene fluoride, polyacrylonitrile, polymethyl methacrylate, polytetrafluoroethylene, Or polyimide, polyamide imide, styrene butadiene rubber polymer, acrylate rubber, sodium carboxymethyl cellulose and the like can be used. As the solvent, N-methylpyrrolidone, acetone, water and the like can be used.

The content of the cathode active material, the conductive agent, the binder and the solvent is a level commonly used in a lithium battery.

Next, a negative electrode plate is prepared.

The negative electrode active material composition is prepared by mixing the negative electrode active material, the conductive agent, the binder and the solvent in the same manner as in the above-mentioned positive electrode plate. The negative electrode active material composition is coated and dried directly on the copper current collector to prepare a negative electrode plate or a negative active material film cast on a separate support and peeled from the support is laminated on the copper current collector to obtain an negative electrode plate. Alternatively, the negative electrode active material composition may be prepared in the form of an electrode ink containing an excessive amount of solvent and printed on a support by an ink jet method or a gravure printing method to produce a negative electrode plate. The printing method is not limited to the above method, and any method that can be used for general coating and printing can be used.

Examples of the anode active material used for the anode include graphite-based materials such as graphite particles; Lithium-alloyable metals such as silicon fine particles; Graphite / silicon composite; Transition metal oxides such as lithium titanium oxide (Li ₄ Ti ₅ O ₁₂ ); And the like may be used, but they are not limited thereto, and any of those used in the technical field can be used. For example, graphite particles are natural graphite, artificial graphite and the like. The size of the graphite particles is preferably 5 to 30 占 퐉. The size of the silicon fine particles is preferably 50 nm to 10 mu m, but is not necessarily limited to this range. The graphite particles and the silicon fine particles may be compounded by a general method used in the related art such as mechanical milling to form a graphite / silicon composite.

The conductive agent, the binder and the solvent may be the same as those used for the production of the positive electrode plate. The content of the negative electrode active material, the conductive agent, the binder and the solvent is a level commonly used in a lithium battery.

A plasticizer may be added to the cathode active material composition and the anode active material composition to form pores inside the electrode plate.

Next, a separator is prepared.

The positive electrode and the negative electrode may be separated by a separator, and the separator may be any as long as it is commonly used in a lithium battery. A separator having a low resistance against the ion movement of the electrolyte and excellent in the ability to impregnate the electrolyte is suitable. For example, a material selected from a glass fiber, a polyester, a Teflon, a polyethylene, a polypropylene, a polytetrafluoroethylene (PTFE), or a combination thereof, and may be in the form of a nonwoven fabric or a woven fabric. More specifically, in a lithium ion battery, a separable separator such as polyethylene or polypropylene is used, and in a lithium ion polymer battery, a separator having an excellent ability to impregnate an organic electrolyte can be used.

The above separator can be produced by the following method. After the separator composition is prepared by mixing a polymer resin, a filler, and a solvent, the separator composition is directly coated on the electrode and dried to form a separator film, or the separator composition is cast on a support and dried, The separator film may be laminated on the electrode.

The polymer resin is not particularly limited and any substance can be used as long as it is used as a binder for an electrode plate. For example, vinylidene fluoride / hexafluoropropylene copolymer, polyvinylidene fluoride, polyacrylonitrile, polymethyl methacrylate or mixtures thereof may be used. It is suitable to use a vinylidene fluoride / hexafluoropropylene copolymer having a hexafluoropropylene content of 8 to 25% by weight.

Next, an electrolyte is prepared.

As the electrolyte, a gel polymer electrolyte according to the above exemplary embodiments may be used. For example, the gel polymer electrolyte may include a polymer produced by polymerizing a first lithium salt, an organic solvent, a fluorine compound, and a monomer represented by Formula 1 below:

&Lt; Formula 1 >

H ₂ C = C- (OR) _n -OCH = CH ₂

In the above formula, R is an alkylene group having 2 to 10 carbon atoms, and n is 1 to 1000.

A separator is disposed between the positive electrode plate and the negative electrode plate to form a battery structure. The cell structure is wound or folded to be housed in a cylindrical battery case or a prismatic battery case, and then the case is filled with a first electrolyte containing the fluorine compound and an organic solvent, and a second electrolytic solution containing the monomer of Formula 1 and an organic solvent Nuclei are sequentially injected to complete the lithium ion polymer battery. As the polymerization reaction proceeds while the first electrolyte and the second electrolyte are mixed, a gel polymer electrolyte in which the polymer is impregnated with an organic solvent can be obtained.

At this time, the first lithium salt may be further included in the first electrolyte or the second electrolyte.

Alternatively, in the lithium battery, the gel polymer electrolyte may be formed by coating and printing on a positive electrode plate and / or a negative electrode plate. For example, a first electrolyte containing the fluorine compound and an organic solvent, and a second electrolyte containing the monomer of Formula 1 and an organic solvent are coated or printed simultaneously or sequentially on a negative electrode plate and / or a positive electrode plate The gel polymer electrolyte may further comprise a first lithium salt. A separator is disposed between the positive electrode plate and the negative electrode plate to form a battery structure. May be wound or folded to be accommodated in the cylindrical battery case or the rectangular battery case to complete the lithium ion polymer battery.

The lithium ion polymer battery may be a flexible battery capable of deforming in battery form. For example, the lithium ion polymer battery can be easily bent.

According to still another embodiment of the present invention, there is provided a method for preparing a gel polymer electrolyte, comprising: preparing a first solution containing a fluorine compound and an organic solvent; and a second solution containing a monomer and an organic solvent, respectively; And mixing the first solution and the second solution, wherein the first solution or the second solution further comprises a first lithium salt:

&Lt; Formula 1 >

H ₂ C = C- (OR) _n -OCH = CH ₂

In the above formula, R is an alkylene group having 2 to 10 carbon atoms, and n is 2 to 1000.

In the method for producing a gel polymer electrolyte, the fluorine compound reacts with residual moisture in an organic solvent to produce a protonic acid or a Lewis acid, and the first lithium salt is inert to the remaining water. By mixing the first solution and the second solution, the fluorine compound reacts with the residual moisture in the organic solvent to produce a protonic acid or a Lewis acid, and by the protonic acid or the Lewis acid, the cationic polymerization of the monomer of the formula Can be disclosed to obtain a polymer.

The polymer produced by polymerizing the monomer of Formula 1 may be in a gel state by being impregnated with the electrolyte containing the first lithium salt, organic solvent and fluorine compound. For example, the polymer may include an electrolyte solution containing the first lithium salt, an organic solvent, and a fluorine compound before being fully cured. The electrolyte can not be contained after the polymer is completely cured.

The polymerization of the monomer of Formula 1 may proceed at room temperature. The ambient temperature may range, for example, from a temperature above which the lithium salt precipitates to a temperature below the boiling point of the organic solvent. For example, from 10 to 40 캜.

Further, since the polymerization is initiated by a protonic acid or a Lewis acid generated by reacting the fluorine compound with the residual moisture in the organic solvent, other polymerization initiating devices such as heat, ultraviolet rays and the like are not required. Therefore, the process for producing the gel polymer electrolyte is simple and easy.

When the first solution and the second solution are mixed in the gel polymer electrolyte production method, the rate of the polymerization reaction can be controlled depending on the type and content of the fluorine compound capable of producing the protonic acid or the Lewis acid. For example, if the content of the fluorine compound is low or the content of the fluorine compound is high, the polymerization reaction may be slowed down if the concentration of the protonic acid or Lewis acid generated by the fluorine compound is low. On the other hand, if the content of the fluorine compound is high or the content of the fluorine compound is low, the rate of the polymerization reaction may be increased when the concentration of the protonic acid or the Lewis acid produced by the fluorine compound is high.

The specific method of mixing the first solution and the second solution in the gel polymer electrolyte production method is not particularly limited as long as it can be used in the art. For example, the first solution and the second solution may be mixed by simultaneously or sequentially coating or printing the first solution and the second solution on the anode plate and / or the cathode plate.

The fluorine compound capable of producing the protonic acid or the Lewis acid may be a fluorinated organic compound, a second lithium salt containing fluorine, or a mixture thereof.

For example, the fluorinated organic compound may be at least one compound selected from the group consisting of the following formulas (2) to (8), but is not limited thereto. The fluorinated organic compound may be a fluorinated compound capable of reacting with residual moisture in the electrolyte solution to produce protonic acid or Lewis acid Any organic compound can be used:

&Lt; Formula 2 > < EMI ID =

&Lt; Formula 6 > < EMI ID =

In the above formulas, R ₁ to R ₃ independently represent hydrogen or an alkyl group having 1 to 10 carbon atoms which is substituted or unsubstituted with a fluorine atom, and R ₄ to R ₉ independently represent a fluorine atom, Alkyl group having 1 to 10 carbon atoms, and at least one of R ₄ to R ₉ is a fluorine atom.

The second lithium salt containing fluorine may be LiBF ₄ , LiPF ₆ , LiAsF ₆ , LiSbF ₆ , LiPF ₃ (CF ₂ CF ₃ ) _3, or a mixture thereof, but is not limited thereto. And a lithium salt capable of reacting to form a protonic acid or a Lewis acid can be used.

The first lithium salt does not react with water to produce a protonic acid or a Lewis acid. That is, it is inactive to a trace amount of water in the organic solvent. The first lithium salt does not generate hydrogen ions that react with moisture to form a protonic acid or a Lewis acid.

For example, the first lithium salt may be LiCl, LiI, LiAlO ₂ , LiAlCl ₄ , LiClO ₄ , LiCF ₃ CO ₂ , LiN (COCF ₃ ) ₂ , LiN (COCF ₂ CF ₃ ) ₂ , LiCF ₃ SO ₃ , LiCF _{3 CF 2 SO 3, LiC 4} F 9 SO 3, LiN (CF 3 SO 2) 2, LiN (C 2 F 5 SO 2) 2, LiN (C p F 2p + 1 SO 2) (C q F 2q + ₁ SO ₂ ) (where p and q are integers), lithium difluoro (oxalato) borate, LiFOB, lithium bis (oxalato) borate, LiBOB, (Malonato oxalato) borate, LiMOB), or a mixture thereof, but is not limited thereto, and may be a lithium salt that does not generate a protonic acid or a Lewis acid by reacting with moisture in an electrolyte Can be used.

In the method for producing a gel polymer electrolyte, the content of the fluorine compound may be 0.1 to 30 wt% of the total weight of the mixed solution of the first solution and the second solution. The above content range is suitable for controlling the rate of the cationic polymerization reaction of the monomer of the formula (1). That is, the above content range is suitable for the production of a gel polymer electrolyte including a polymer in a gel state. For example, the content of the fluorine compound may be 0.5 to 20 wt% of the total weight of the mixed solution of the first solution and the second solution.

In the method for producing a gel polymer electrolyte, the content of the compound of Formula 1 may be 0.1 to 30% by weight based on the total weight of the mixed solution of the first solution and the second solution. That is, the above content range is suitable for a gel polymer electrolyte including a polymer in a gel state. For example, the content of the polymer may be 0.5 to 20 wt% of the total weight of the mixed solution of the first solution and the second solution. However, if the charging and discharging characteristics of the lithium battery including the gel polymer electrolyte can be improved, it is also possible that the polymer is used outside the above range.

In the method for preparing a gel polymer electrolyte, the molecular weight of the compound of Formula 1 may be about 100 to about 1,000. And is suitable for the production of a gel polymer electrolyte in which the molecular weight range includes a polymer in a gel state.

According to another embodiment of the present invention, there is provided a lithium battery manufacturing method comprising the steps of: preparing an electrode, a first solution containing a fluorine compound, and a second solution containing a monomer of the following formula 1, respectively; And forming a gel polymer electrolyte by coating or printing the first solution and the second solution on the electrode, wherein the gel polymer electrolyte further comprises an organic solvent and a first lithium salt,

&Lt; Formula 1 >

H ₂ C = C- (OR) _n -OCH = CH ₂

In the above formula, R is an alkylene group having 2 to 10 carbon atoms, and n is 2 to 1000.

In the lithium cell manufacturing method, in the step of forming the gel polymer electrolyte, the first solution and the second solution may be coated or printed simultaneously or sequentially on the electrode.

In the lithium battery manufacturing method, the fluorine compound may react with residual moisture in an organic solvent to produce a protonic acid or a Lewis acid, and the first lithium salt may be inert to the residual moisture.

In the lithium battery manufacturing method, the first solution and the second solution are coated or printed sequentially or simultaneously on the electrode, so that the fluorine compound contained in the first solution reacts with the residual moisture of the organic solvent to form protonic acid or Lewis acid And the protonic acid or Lewis acid initiates the cationic polymerization of the monomer of Formula 1 contained in the second solution.

The polymer is impregnated with an electrolyte solution containing a first lithium salt, an organic solvent and a fluorine compound contained in the first solution and / or the second solution before the polymer is completely cured by the polymerization reaction, Can be formed.

In addition, the cationic polymerization of the monomer of the formula (1) is initiated by protonic acid or hydrofluoric acid, which is produced by reacting the fluorine compound with residual moisture in the organic solvent, and thus does not require any polymerization initiator such as heat or ultraviolet rays. Therefore, the process for producing the gel polymer electrolyte is simple and easy.

In the lithium battery production method, the cationic polymerization of the monomer of the formula (1) can proceed at room temperature. That is, the production method of the lithium battery is easy because it forms a gel polymer electrolyte at room temperature by a coating or printing method without a curing device and an initiator.

In the method for producing a lithium battery, the protonic acid or the fluorine compound capable of generating hydrofluoric acid may be a fluorinated organic compound, a second lithium salt containing fluorine, or a mixture thereof.

In the method for producing a lithium battery, the fluorinated organic compound may be at least one compound selected from the group consisting of the following Chemical Formulas (2) to (8), but is not limited thereto. The fluorinated organic compound may react with moisture in the electrolyte to produce protonic acid or hydrofluoric acid Any fluorinated organic compound can be used:

&Lt; Formula 2 > < EMI ID =

&Lt; Formula 6 > < EMI ID =

In the above formulas, R ₁ to R ₃ independently represent hydrogen or an alkyl group having 1 to 10 carbon atoms which is substituted or unsubstituted with a fluorine atom, and R ₄ to R ₉ independently represent a fluorine atom, And at least one of R ₄ to R ₉ is a fluorine atom.

The second lithium salt containing fluorine in the method for producing a lithium battery may be LiBF ₄ , LiPF ₆ , LiAsF ₆ , LiSbF ₆ , LiPF ₃ (CF ₂ CF ₃ ) ₃ , or a mixture thereof. However, And a lithium salt capable of reacting with moisture in the electrolytic solution to produce a protonic acid or a Lewis acid can be used.

The first lithium salt does not react with water to produce protonic acid or hydrofluoric acid. That is, it is inactive to a trace amount of water in the organic solvent. The first lithium salt does not generate hydrogen ions that react with moisture to form a protonic acid or a Lewis acid.

For example, the first lithium salt is selected from the group consisting of LiCF ₃ CO ₂ , LiN (COCF ₃ ) ₂ , LiN (COCF ₂ CF ₃ ) ₂ , LiCF ₃ SO ₃ , LiCF ₃ CF ₂ SO ₃ , LiC ₄ F ₉ SO ₃ , _{LiN (CF 3 SO 2) 2} , LiN (C 2 F 5 SO 2) 2, LiN (C p F 2p + 1 SO 2) (C q F 2q + 1 SO 2) (p and q are integers), lithium Lithium difluoro (oxalato) borate, Lithium bis (oxalato) borate, Lithium bis (oxalato) borate, Lithium bis (oxalato) borate, Lithium (malonato oxalate) borate oxalato) borate, LiMOB), or a mixture thereof, but is not limited thereto. Any lithium salt that does not generate protonic acid or hydrofluoric acid by reacting with moisture in the electrolytic solution can be used.

The technical idea will be explained in more detail through the following examples and comparative examples. It should be noted, however, that the embodiments are illustrative of the technical idea, and the scope of the technical idea is not limited thereto.

(Preparation of composite anode active material)

Production Example 1

3 g of graphite particles having an average particle size of 25 μm (C1SR, Japanese carbon) and 1.5 g of silicon fine particles having an average particle diameter of 100 nm (Spherical Type, US Nanostructured & Amorphous Materials, Inc.) And milled for 60 minutes to prepare a graphite / silicon composite.

(Production of lithium battery including composite anode active material)

Example 1

70 parts by weight of the negative electrode active material prepared in Preparation Example 1, 15 parts by weight of graphite based conductive agent (SFG6, Timcal Inc.), and 5 parts by weight of polyvinylidene fluoride (PVdF) in N-methylpyrrolidone, Was dissolved in agar mortar to prepare a slurry. The slurry was coated on a copper collector having a thickness of 15 mu m to a thickness of about 60 mu m using a doctor blade, dried in a hot air drier at 100 DEG C for 2 hours, and dried again in a vacuum at 120 DEG C for 2 hours, .

Using the negative electrode plate, a lithium-metal counter electrode and a polypropylene separator (Celgard 3510) were used as a separator, and the following first electrolyte solution and second electrolyte solution were sequentially added, followed by addition of CR-2016 Coin cell of standard size was manufactured.

The first electrolyte was prepared by adding 50 parts by weight of a solution of 1.3 M LiN (SO ₂ C ₂ F ₅ ) ₂ dissolved in EC (ethylene carbonate) + DEC (diethyl carbonate) (3: 20 parts by weight.

The second electrolyte solution was prepared by adding 50 parts by weight of a solution prepared by dissolving 1.3 M LiN (SO ₂ C ₂ F ₅ ) ₂ in EC (ethylene carbonate) + DEC (diethyl carbonate) (3: 7 by volume) DEGDVE).

Example 2

Except that 2 parts by weight of triethylene glycol divinyl ether (TEGDVE) was used instead of 3 parts by weight of diethylene glycol divinyl ether in the second electrolyte solution.

Example 3

Except that 2 parts by weight of polyethylene glycol divinyl ether (PEGDVE) (Aldrich, USA, molecular weight 240) instead of 3 parts by weight of diethylene glycol divinyl ether was used in the second electrolyte solution.

Example 4

Except that 1 part by weight of 1,4-butanediol divinyl ether (1,4-BDDVE) was used instead of 3 parts by weight of diethylene glycol divinyl ether in the second electrolyte solution.

Comparative Example 1

The procedure of Example 1 was repeated except that diethylene glycol divinyl ether (DEGDVE) was not added to the second electrolyte solution.

Comparative Example 2

The procedure of Example 1 was repeated except that no fluoroethylene carbonate (FEC) was added to the first electrolyte solution.

Comparative Example 3

The procedure of Example 1 was repeated except that LiPF ₆ was used instead of LiN (SO ₂ C ₂ F ₅ ) ₂ in the first electrolyte solution.

(Preparation (1) of a lithium battery including a transition metal oxide cathode active material)

Example 5

80 parts by weight of lithium iron phosphate (LiFePO4, Phostech Lithium, USA) having an average particle diameter of 200 nm, 10 parts by weight of a graphite based conductive agent (Super-P, Timcal Inc.) and 10 parts by weight of polyvinylidene fluoride (PVdF) Methylpyrrolidone solvent to prepare a 5 wt% solid solution, and then printed several tens of times on an aluminum current collector having a thickness of 15 탆 by using an ink jet printer (Dimatix, USA) to measure the total thickness of the active material layer to 8 탆 A positive electrode plate was prepared.

Using the above-mentioned positive electrode plate, a lithium-metal counter electrode and a polypropylene separator (Celgard 3510) were sequentially used as a separator, and the following first and second electrolytes were sequentially added, and CR-2016 Coin cell of standard size was manufactured.

The first electrolyte was prepared by adding 0.5 M LiBF ₄ to 50 parts by weight of a solution in which 1.3 M LiN (SO ₂ C ₂ F ₅ ) ₂ was dissolved in EC (ethylene carbonate) + DEC (diethyl carbonate) (3: 7 by volume) .

The second electrolyte solution was prepared by adding 50 parts by weight of a solution prepared by dissolving 1.3 M LiN (SO ₂ C ₂ F ₅ ) ₂ in EC (ethylene carbonate) + DEC (diethyl carbonate) (3: 7 by volume) DEGDVE).

Example 6

Except that 5 parts by weight of diethylene glycol divinyl ether was used instead of 2.5 parts by weight of diethylene glycol divinyl ether in the second electrolyte solution.

Example 7

Except that 10 parts by weight of diethylene glycol divinyl ether was used instead of 2.5 parts by weight of diethylene glycol divinyl ether in the second electrolyte solution.

Example 8

Except that 10 parts by weight of triethylene glycol divinyl ether was used instead of 2.5 parts by weight of diethylene glycol divinyl ether in the second electrolyte solution.

Comparative Example 4

The procedure of Example 5 was repeated except that diethylene glycol divinyl ether (DEGDVE) was not added to the second electrolyte solution.

(Preparation (2) of a lithium battery including a transition metal oxide negative electrode active material)

Example 9

80 parts by weight of lithium titanium oxide (Li ₄ Ti ₅ O ₁₂ , nGimat, USA) having an average particle diameter of 100 nm, 10 parts by weight of a graphite based conductive agent (Super-P, Timcal Inc.), and 10 parts by weight of polyvinylidene fluoride Was dissolved in N-methylpyrrolidone to prepare a 5 wt% solids solution. Then, the solution was printed several tens times using an inkjet printer (Dimatix, USA) on a copper collector having a thickness of 15 탆 to obtain a total thickness Lt; RTI ID = 0.0 &gt; pm. &Lt; / RTI &gt;

Using the negative electrode plate, a lithium-metal counter electrode and a polypropylene separator (Celgard 3510) were used as a separator, and the following first electrolyte solution and second electrolyte solution were sequentially added, followed by addition of CR-2016 Coin cell of standard size was manufactured.

The first electrolyte was prepared by adding 0.5 M LiBF ₄ to 50 parts by weight of a solution in which 1.3 M LiN (SO ₂ C ₂ F ₅ ) ₂ was dissolved in EC (ethylene carbonate) + DEC (diethyl carbonate) (3: 7 by volume) .

The second electrolyte solution was prepared by adding 50 parts by weight of a solution prepared by dissolving 1.3 M LiN (SO ₂ C ₂ F ₅ ) ₂ in EC (ethylene carbonate) + DEC (diethyl carbonate) (3: 7 by volume) DEGDVE).

Example 10

Except that 5 parts by weight of diethylene glycol divinyl ether was used instead of 2.5 parts by weight of diethylene glycol divinyl ether in the second electrolyte solution.

Example 11

Except that 10 parts by weight of diethylene glycol divinyl ether was used instead of 2.5 parts by weight of diethylene glycol divinyl ether in the second electrolyte solution.

Example 12

Except that 10 parts by weight of triethylene glycol divinyl ether was used instead of 2.5 parts by weight of diethylene glycol divinyl ether in the second electrolyte solution.

Comparative Example 5

The procedure of Example 9 was repeated except that diethylene glycol divinyl ether (DEGDVE) was not added to the second electrolyte solution.

The content of the fluorine compound and polymer contained in the gel polymer electrolyte of the lithium battery prepared in Examples 1 to 12 is shown in Table 1 below.

<Table 2>

Polymer electrolyte state Fluorine compound content
[weight%] Polymer Polymer Content
[weight%] Example 1 Gel 16.7 3 Example 2 Gel 16.7 2 Example 3 Gel 16.7 2 Example 4 Gel 16.7 One Example 5 Gel 4.5 2.5 Example 6 Gel 4.5 5 Example 7 Gel 4.5 10 Example 8 Gel 4.5 10 Example 9 Gel 4.5 2.5 Example 10 Gel 4.5 5 Example 11 Gel 4.5 10 Example 12 Gel 4.5 10 Comparative Example 1 Liquid 16.7 0 Comparative Example 2 Liquid 0 0 Comparative Example 4 Liquid 4.5 0 Comparative Example 5 Liquid 4.5 0

Evaluation example 1: charge-discharge experiment

The lithium batteries prepared in Examples 1 to 4 and Comparative Examples 1 to 3 were charged at a current of 100 mA per 1 g of the negative electrode active material until the voltage reached 0.001 V (vs. Li), followed by a 10-minute pause , And discharged again at the same current until the voltage reached 1.5 V (vs. Li). This was repeated up to the third cycle, then charged and discharged at a current of 200 mA / g from the fourth cycle to the 47th cycle, and then charged and discharged again at a current of 100 mA / g from the 48th cycle to the 50th cycle. Initial efficiency, capacity retention and average efficiency at 200 mA / g were measured. The results are shown in Table 2 below.

Evaluation Example 2: Charge-discharge experiment

The lithium batteries prepared in Examples 5 to 8 and Comparative Example 4 were charged until the voltage reached 4.1 V (vs. Li) at a current of 15 mA per 1 g of the cathode active material, followed by a 10-minute rest period, The same current was discharged until the voltage reached 2.7 V (vs. Li). This was repeated up to 50 cycles. Initial efficiency, capacity retention and average efficiency at 15 mA / g were measured. The results are shown in Table 2 below.

Evaluation Example 3: Charge-discharge experiment

The lithium batteries prepared in Examples 9 to 12 and Comparative Example 5 were charged at a current of 15 mA per 1 g of the negative electrode active material until the voltage reached 1.1 V (vs. Li), followed by a 10-minute rest period, The same current was discharged until the voltage reached 2.0 V (vs. Li). This was repeated up to 50 cycles. Initial efficiency, capacity retention and average efficiency at 15 mA / g were measured. The results are shown in Table 2 below.

The state of the polymer electrolyte and charge-discharge characteristics of the lithium batteries obtained in Examples 1 to 12 and Comparative Examples 1 to 5 are shown in Table 2 below. The average efficiency at 15 mA / g (Examples 5 to 12 and Comparative Examples 4 to 5 (Comparative Examples 1 to 4) and Comparative Examples 1 to 3 ) Is calculated from the following equations.

&Quot; (1) &quot;

Initial efficiency = first cycle discharge capacity / first cycle charge capacity

&Quot; (2) &quot;

Capacity retention rate in the 50th cycle = 50th cycle discharge capacity / first cycle discharge capacity

&Quot; (3) &quot;

Average efficiency at 200 mA / g = average of (discharge capacity / charge capacity) in each cycle

&Quot; (4) &quot;

Average efficiency at 15 mA / g = average of (discharge capacity / charge capacity) in each cycle

<Table 2>

Polymer electrolyte state Initial efficiency [%] Capacity retention rate [%] in the 50th cycle Average efficiency [%] Example 1 Gel 68.40 86.58 98.89 Example 2 Gel 68.47 88.18 98.95 Example 3 Gel 68.52 84.00 98.92 Example 4 Gel 68.19 86.85 98.88 Example 5 Gel 97.14 96.61 99.71 Example 6 Gel 99.70 98.09 99.95 Example 7 Gel 99.64 98.80 99.90 Example 8 Gel 99.53 98.29 99.93 Example 9 Gel 64.65 60.55 96.24 Example 10 Gel 68.08 63.38 96.35 Example 11 Gel 69.39 82.41 96.78 Example 12 Gel 68.68 87.10 95.55 Comparative Example 1 Liquid 67.56 80.43 98.40 Comparative Example 2 Liquid 67.49 76.52 98.58 Comparative Example 3 Liquid + separated polymer Not measurable Not measurable Not measurable Comparative Example 4 Liquid 98.25 62.65 98.78 Comparative Example 5 Liquid 65.02 56.97 95.18

As shown in Table 1, the initial efficiency, the capacity retention rate, and the average efficiency were increased in Examples 1 to 4 as compared with Comparative Examples 1 and 2.

In Comparative Example 3, since the polymerization reaction proceeds rapidly as the first electrolyte and the second electrolyte are mixed, the gel polymer electrolyte containing the gel polymer impregnated in the organic solvent is not formed and the solid polymer separated from the organic solvent And the charge / discharge test was impossible.

In Examples 1 to 4, since the gel polymer electrolyte containing the gel polymer is formed, the gel polymer electrolyte suppresses the irreversible reaction between the complex-type anode active material having irregular surface and the electrolytic solution, The charge / discharge characteristics can be improved.

In Examples 5 to 8, the initial efficiency, the capacity retention rate, and the average efficiency were increased as compared with Comparative Example 4. Particularly, the capacity retention rate is remarkably improved.

In Examples 9 to 12, the initial efficiency, the capacity retention rate, and the average efficiency were increased as compared with Comparative Example 5. Particularly, the capacity retention rate is remarkably improved.

Claims (35)

A first lithium salt; Organic solvent; Fluorine compounds; And A gel polymer electrolyte comprising: a polymer formed by polymerizing a monomer represented by Formula 1: &Lt; Formula 1 > H ₂ C = C- (OR) _n -OCH = CH ₂ Wherein R is an alkylene group having 2 to 10 carbon atoms, n is an integer of 1 to 1000, Wherein the fluorine compound is a fluorinated organic compound, Wherein the fluorinated organic compound comprises at least one compound selected from the group consisting of the following formulas (2) to (8) &Lt; Formula 2 > < EMI ID =

&Lt; Formula 6 > < EMI ID =

In the above equations, R ₁ to R ₃ independently represent hydrogen or an alkyl group having 1 to 10 carbon atoms which is substituted or unsubstituted with a fluorine atom and R ₄ to R ₉ independently represent a fluorine atom or a substituted or unsubstituted, Lt; / RTI &gt; At least one of R ₄ to R ₉ is a fluorine atom, The polymer is obtained by the reaction of a protonic acid or a Lewis acid produced by reacting the residual water in the organic solvent with the fluorine compound and the monomer of the above formula (1). The method according to claim 1, wherein the fluorine compound reacts with residual moisture in the organic solvent to produce a protonic acid or a Lewis acid, and the first lithium salt is added to the residual water in the organic solvent Inert gel polymer electrolyte. delete The gel polymer electrolyte according to claim 1, wherein the gel is formed by impregnating the polymer with an electrolytic solution containing a first lithium salt, an organic solvent, and a fluorine compound. delete delete delete According to claim 1, wherein the first lithium salt _{LiCF 3 CO 2, LiN (COCF} 3) 2, LiN (COCF 2 CF 3) 2, LiCF 3 SO 3, LiCF 3 CF 2 SO 3, LiC 4 F 9 SO _{3, LiN (CF 3 SO 2} ) 2, LiN (C 2 F 5 SO 2) 2, LiN (C p F 2p + 1 SO 2) (C q F 2q + 1 SO 2) (p and q is an integer) , Lithium difluoro (oxalato) borate, LiFOB), lithium bis (oxalato) borate, LiBOB, and lithium (malonate oxalate) borate Lithium (malonato oxalato) borate, LiMOB). The gel polymer electrolyte according to claim 1, wherein the content of the fluorine compound is 0.1 to 30 wt% of the total weight of the gel polymer electrolyte. The gel polymer electrolyte according to claim 1, wherein the content of the fluorine compound is 0.5 to 20 wt% of the total weight of the gel polymer electrolyte. The gel polymer electrolyte according to claim 1, wherein the content of the polymer is 0.1 to 30% by weight of the total weight of the gel polymer electrolyte. The gel polymer electrolyte according to claim 1, wherein the content of the polymer is 0.5 to 20 wt% of the total weight of the gel polymer electrolyte. anode; cathode; And A lithium battery comprising the gel polymer electrolyte according to any one of claims 1, 2, 4, and 8 to 12. Preparing a first solution containing a fluorine compound and an organic solvent, and a second solution containing a monomer and an organic solvent of the following formula 1, respectively; And Mixing the first solution and the second solution, Wherein the first solution or the second solution further comprises a first lithium salt. &Lt; Formula 1 > H ₂ C = C- (OR) _n -OCH = CH ₂ Wherein R is an alkylene group having 2 to 10 carbon atoms, n is 2 to 1000, Wherein the fluorine compound is a fluorinated organic compound, Wherein the fluorinated organic compound comprises at least one compound selected from the group consisting of the following formulas (2) to (8) &Lt; Formula 2 > < EMI ID =

&Lt; Formula 6 > < EMI ID =

In the above equations, R ₁ to R ₃ independently represent hydrogen or an alkyl group having 1 to 10 carbon atoms which is substituted or unsubstituted with a fluorine atom and R ₄ to R ₉ independently represent a fluorine atom or a substituted or unsubstituted, Lt; / RTI &gt; At least one of R ₄ to R ₉ is a fluorine atom, Wherein the gel comprises a polymer, The polymer is obtained by the reaction of a protonic acid or a Lewis acid produced by reacting the residual water in the organic solvent with the fluorine compound and the monomer of the above formula (1). 15. The method of claim 14, wherein the fluorine compound reacts with the residual moisture in the organic solvent to produce a protonic acid or a Lewis acid, and the first lithium salt reacts with the residual moisture in the organic solvent Inactive gel polymer electrolyte. 15. The method for producing a gel polymer electrolyte according to claim 14, wherein the gel is formed by impregnating an electrolyte comprising the first lithium salt, an organic solvent, and a fluorine compound into a polymer produced by polymerization of the monomer of Formula 1. 17. The method of producing a gel polymer electrolyte according to claim 16, wherein the polymerization is performed at room temperature. delete delete delete Of claim 14, wherein the first lithium salt _{LiCF 3 CO 2, LiN (COCF} 3) 2, LiN (COCF 2 CF 3) 2, LiCF 3 SO 3, LiCF 3 CF 2 SO 3, LiC 4 F 9 SO _{3, LiN (CF 3 SO 2} ) 2, LiN (C 2 F 5 SO 2) 2, LiN (C p F 2p + 1 SO 2) (C q F 2q + 1 SO 2) (p and q is an integer) , Lithium difluoro (oxalato) borate, LiFOB), lithium bis (oxalato) borate, LiBOB, and lithium (malonate oxalate) borate Lithium (malonato oxalato) borate, LiMOB). 15. The method for producing a gel polymer electrolyte according to claim 14, wherein the content of the fluorine compound is 0.1-30 wt% of the total weight of the mixed solution of the first solution and the second solution. 15. The method for producing a gel polymer electrolyte according to claim 14, wherein the content of the fluorine compound is 0.5 to 20 wt% of the total weight of the mixed solution of the first solution and the second solution. 15. The method for producing a gel polymer electrolyte according to claim 14, wherein the content of the compound of Formula 1 is 0.1 to 30 wt% of the total weight of the mixed solution of the first solution and the second solution. 15. The method for producing a gel polymer electrolyte according to claim 14, wherein the content of the compound of Formula 1 is 0.5 to 20 wt% of the total weight of the mixed solution of the first solution and the second solution. 15. The method for preparing a gel polymer electrolyte according to claim 14, wherein the compound of formula (1) has a molecular weight of 100 to 1000. delete delete delete delete delete delete delete delete delete