WO2016053064A1 - Gel polymer electrolyte and lithium secondary battery comprising same - Google Patents

Abstract

The present invention relates to a gel polymer electrolyte and a lithium secondary battery comprising same, the gel polymer electrolyte comprising a polymer network and an electrolyte solution impregnated on the polymer network, wherein the polymer network is formed having an oligomer bound in a three-dimensional structure, the oligomer comprising: a unit A which is derived from a monomer comprising at least one or more of a copolymerizable acrylate or acrylic acid; a unit C which comprises urethane; and a unit E which comprises siloxane.

Description

Gel polymer electrolyte and lithium secondary battery comprising same

Cross Citation with Related Application (s)

This application claims the benefit of priority based on Korean Patent Application No. 10-2014-0133433 dated October 2, 2014 and Korean Patent Application No. 10-2015-0139401 dated October 2, 2015. All content disclosed in the literature is included as part of this specification.

Technical Field

The present invention relates to a gel polymer electrolyte and a lithium secondary battery comprising the same.

As technology development and demand for mobile devices increase, the demand for secondary batteries as energy sources is rapidly increasing, and lithium secondary batteries having high energy density and voltage are commercially used.

Lithium metal oxide is used as a positive electrode active material of a lithium secondary battery, and lithium metal, a lithium alloy, crystalline or amorphous carbon or a carbon composite material is used as a negative electrode active material. The secondary battery may be coated with a positive electrode and a negative electrode active material to a current collector in a suitable thickness and length, or the active material itself in a film form, and then wound or laminated together with a separator as an insulator to manufacture an electrode assembly in a can or a similar container. After putting, it is manufactured by the method of inject | pouring electrolyte solution.

Conventionally, as electrolytes for electrochemical devices such as batteries and electric double layer capacitors using an electrochemical reaction, an electrolyte in a liquid state, particularly an ion conductive liquid electrolyte in which salts are dissolved in a non-aqueous organic solvent, has been mainly used.

However, the use of the liquid electrolyte in this way not only deteriorates the electrode material and volatilizes the organic solvent, but also causes problems in safety due to the combustion caused by an increase in the ambient temperature and the temperature of the battery itself. In particular, a lithium secondary battery has a problem in that gas is generated inside the battery due to decomposition of a carbonate organic solvent and / or side reaction between the organic solvent and the electrode during charging and discharging, thereby expanding the thickness of the battery. Thus, the amount of gas generated is further increased.

The gas generated continuously causes an increase in the internal pressure of the battery, which causes the rectangular battery to swell in a specific direction and explodes, or to deform the center of a specific surface of the battery, thereby degrading safety. It causes a local difference in the electrode reaction does not occur the same across the entire electrode surface causes a disadvantage of deterioration of the battery performance.

On the other hand, as the interest in energy storage technology increases, there is a demand for the development of a secondary battery that can be charged and discharged with small size, light weight, and high capacity. Accordingly, the development of a battery using a polymer electrolyte made of a polymer rather than a liquid electrolyte has recently attracted attention.

Generally, battery performance is known to decrease, whereas battery safety is improved in the order of liquid electrolyte <gel polymer electrolyte <solid polymer electrolyte.

That is, the gel polymer electrolyte has a disadvantage in that the conductivity of lithium ions is lower than that of a liquid electrolyte composed only of an electrolyte solution. Therefore, in order to improve this, a method of thinning the thickness of the gel polymer electrolyte has been proposed. However, in this case, there is a problem in improving battery performance and safety, such as a decrease in mechanical strength, a short circuit between the positive electrode and the negative electrode, and a short circuit in the polymer electrolyte.

Accordingly, there is a need for development of a gel polymer electrolyte having improved battery safety and battery performance.

Prior art literature

Republic of Korea Patent Publication No. 10-2013-0058403

The problem to be solved in the present invention is to provide a gel polymer electrolyte comprising a polymer network consisting of an oligomer comprising a urethane, acrylate and siloxane.

In addition, the present invention provides a lithium secondary battery including the gel polymer electrolyte.

In order to solve the above problems, an embodiment of the present invention

Polymer networks; And

An electrolyte impregnated on said polymer network,

The polymer network is formed by combining an oligomer comprising a unit A derived from a monomer comprising at least one copolymerizable acrylate or an acrylic acid, a unit C including a urethane, and a unit E including a siloxane in a three-dimensional structure. A gel polymer electrolyte is provided.

In addition, an embodiment of the present invention

Lithium Salt,

Electrolyte solvent,

Polymerization initiator, and

For a gel polymer electrolyte comprising a gel polymer electrolyte comprising a unit A derived from a monomer comprising at least one copolymerizable acrylate or acrylic acid, a unit C comprising urethane, and an oligomer comprising unit E comprising siloxane To provide a composition.

In addition, an embodiment of the present invention

A positive electrode and a negative electrode capable of occluding and releasing lithium, and a gel polymer electrolyte disposed between the positive electrode and the negative electrode,

The gel polymer electrolyte provides a lithium secondary battery including the gel polymer electrolyte of the present invention.

That is, various embodiments of the present invention provide a gel polymer electrolyte or a lithium secondary battery as follows.

(1) a polymer network; And an electrolyte impregnated on the polymer network, wherein the polymer network comprises unit A derived from monomers comprising at least one copolymerizable acrylate or acrylic acid, unit C comprising urethane, and unit comprising siloxane. Gel polymer electrolyte formed by combining the first oligomer comprising E in a three-dimensional structure.

(2) The gel polymer electrolyte according to the above (1), wherein the first oligomer is represented by the following general formula (1):

[Formula 1]

A- [CE] _k -CA

Where

k is an integer of 1 to 200.

(3) The unit A is a unit derived from at least one compound selected from the group consisting of hydroxymethyl (meth) acrylate, and hydroxyethyl (meth) acrylate, or a compound represented by the following formula (i) The gel polymer electrolyte according to any one of (1) to (2) above, which is a derived unit:

(i).

(4) The gel polymer electrolyte according to any one of (1) to (3), wherein the unit C comprises a unit represented by the following formula (2a) or (2b):

[Formula 2a]

[Formula 2b]

Where

R 'is a linear or nonlinear 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, or a substituted or substituted carbon group having 6 to 20 carbon atoms or At least one selected from the group consisting of an unsubstituted arylene group, a substituted or unsubstituted biarylene group having 6 to 20 carbon atoms, a substituted or unsubstituted arylene group having 6 to 20 carbon atoms, a naphthalene group and an anthracene group.

(5) The gel polymer electrolyte according to any one of (1) to (4), wherein R 'is one compound selected from the group consisting of:

(Ri)

(R-ii)

(R-iii)

(R-iv)

(Rv)

(R-vi)

(R-vii)

(R-viii)

(6) The gel polymer electrolyte according to any one of (1) to (5), wherein the unit E includes a unit represented by the following formula (3):

[Formula 3]

Where

R ₁ and R ₂ are linear or nonlinear alkylene groups having 1 to 5 carbon atoms,

R ₃ and R ₄ are each independently one selected from the group consisting of hydrogen, an alkyl group having 1 to 5 carbon atoms, and a phenyl group,

R ₅ to R ₁₀ are each independently one selected from the group consisting of hydrogen, an alkyl group having 1 to 5 carbon atoms, a phenyl group, and fluorine,

o is an integer of 0 or 1,

p is 0 or an integer from 1 to 400,

r is an integer from 1 to 400,

The molar ratio of p: r is 0: 100 to 80:20.

(7) The gel polymer electrolyte according to any one of (1) to (6), wherein the unit E comprises at least one compound selected from the group consisting of the following Chemical Formulas 3a to 3g:

 [Formula 3a]

[Formula 3b]

[Formula 3c]

[Formula 3d]

[Formula 3e]

[Formula 3f]

[Formula 3g]

Where

p is 0 or an integer from 1 to 400,

r is an integer from 1 to 400,

The molar ratio of p: r is 0: 100 to 80:20.

(8) Unit 1 is 1 mol or 2 mol in 1 mol of the first oligomer,

The gel polymer electrolyte according to any one of (1) to (7), wherein the molar ratio of Unit C: E is 1.005: 1 to 2: 1.

(9) Any of the above (1) to (8), wherein the first oligomer optionally further includes at least one or more units selected from the group consisting of unit B represented by the following formula (4) and unit D represented by the following formula (5): The gel polymer electrolyte according to claim 1.

[Formula 4]

* -CO-R ''-O- *

[Formula 5]

* -O- [R '''-O] _m- *

Where

R '' is a substituted or unsubstituted linear alkylene group having 1 to 10 carbon atoms, or a substituted or unsubstituted nonlinear alkylene group having 1 to 10 carbon atoms,

R '' 'is a substituted or unsubstituted linear alkylene group having 1 to 10 carbon atoms, or a substituted or unsubstituted nonlinear alkylene group having 1 to 10 carbon atoms,

m is an integer of 1-30.

(10) The gel polymer electrolyte according to any one of (1) to (9), wherein the unit B is at least one compound selected from the group consisting of the following groups.

* -CO-CH ₂ CH ₂ -O- * (Bi)

* -CO-CHCH ₃ CH ₂ -O- * (B-ii)

* -CO-CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ -O- * (B-iii)

* -CO-CHCH ₃ CH ₂ CH ₂ -O- * (B-iv)

(11) The gel polymer electrolyte according to any one of (1) to (10), wherein the unit D is at least one compound selected from the group consisting of:

* -O-CH ₂ CH ₂ -O- * (Di)

* -O-CHCH ₃ CH ₂ -O- * (D-ii)

(12) The gel polymer electrolyte according to any one of (1) to (11), wherein the first oligomer is represented by at least one selected from the group consisting of the following Chemical Formulas 6a to 6c.

[Formula 6a]

[A] _s- [B] _n- [CE-] _k -C- [B] _n -A

[Formula 6b]

[A] _s- [CDED] _k -CA

[Formula 6c]

[A] _s- [B] _n- [CDED] _k -C- [B] _n -A.

Where

n is 0 or an integer from 1 to 30,

k is an integer from 1 to 200,

s is 0 or 1.

(13) In 1 mol of the first oligomer, the unit A is 1 mol or 2 mol,

The molar ratio of the unit B: unit C: unit D: unit E is 0 to 35: 2 to 201: 0 to 35: 1 to 200 (wherein units B and D are not 0 at the same time); The gel polymer electrolyte according to any one of 12).

(14) The gel polymer electrolyte according to any one of (1) to (13), wherein the first oligomer is at least one compound selected from the group consisting of Formulas 7a to 7d.

[Formula 7a]

[Formula 7b]

[Formula 7c]

[Formula 7d]

Where

k is an integer from 1 to 200,

n is an integer from 1 to 30,

m is an integer from 1 to 30,

p is an integer from 1 to 400,

r is an integer from 1 to 400,

The molar ratio of p: r is 0: 100 to 80:20.

(15) The gel polymer electrolyte is methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, propyl methacrylate, butyl acrylate, butyl methacrylate, hexyl acrylate, hexyl meta Acrylate, ethylhexyl acrylate, ethylhexyl methacrylate, 2,2,2-trifluoroethyl acrylate, 2,2,2-trifluoroethyl methacrylate, 2,2,3,3-tetra (1) to (14), further comprising a second oligomer comprising a unit derived from fluoropropyl acrylate, and at least one selected from the group consisting of 2,2,3,3-tetrafluoropropyl methacrylate. The gel polymer electrolyte as described in any one of).

(16) The gel polymer electrolyte according to any one of (1) to (15), wherein the second oligomer is contained in an amount of 50% by weight or less based on the total content of the first oligomer.

(17) The gel polymer electrolyte according to any one of (1) to (16), wherein the polymer network further contains inorganic particles on the polymer network.

(18) The gel polymer electrolyte according to any one of (1) to (17), wherein the weight average molecular weight of the first oligomer is 1,000 to 100,000.

(19) The gel polymer electrolyte according to any one of (1) to (18), wherein the gel polymer electrolyte has Li ⁺ ion conductivity of 1.0 × 10 ⁻⁴ S / cm to 2.0 × 10 ⁻² S / cm at a temperature of 25 ° C. (Celsius). Described gel polymer electrolyte.

(20) The gel polymer electrolyte according to any one of (1) to (19), wherein the gel polymer electrolyte has a Li ⁺ ion transfer coefficient of 0.3 or more at a temperature of 25 ° C.

(21) The gel polymer electrolyte according to any one of (1) to (20), wherein the gel polymer electrolyte has a gel content of 1% by weight or more at a temperature of 25 ° C.

(22) The gel polymer electrolyte according to any one of (1) to (21), wherein the gel polymer electrolyte has an unreacted oligomer content of 20% or less relative to the total amount of reactive oligomers charged at 25 ° C.

(23) Unit A derived from monomers comprising at least one copolymerizable acrylate or acrylic acid; Unit C comprising urethane; And unit E comprising siloxane.

(24) comprises oligomers containing units comprising siloxanes,

Li ⁺ ion conductivity of 1.0x10 ^-4 S / cm to 2.0x10 ^-2 S / cm at a temperature of 25 ℃,

A gel polymer electrolyte having a Li ⁺ ion transfer coefficient of 0.3 or more and a content of unreacted oligomers of 20% or less relative to the total amount of reactive oligomers.

(25) an agent comprising unit A derived from a lithium salt, an electrolyte solvent, a polymerization initiator, and a monomer comprising at least one copolymerizable acrylate or acrylic acid, a unit C comprising urethane, and a unit E comprising siloxane The composition for gel polymer electrolytes in any one of said (1)-(23) containing 1 oligomer.

(26) The composition for gel polymer electrolyte according to the above (25), wherein the first oligomer is contained in an amount of 0.5% by weight to 20% by weight based on the total weight of the composition for gel polymer electrolyte.

(27) The composition for a gel polymer electrolyte according to any one of (25) to (26), wherein the first oligomer is represented by the following general formula (1):

[Formula 1]

A- [CE] _k -CA

Where

k is an integer of 1 to 200.

(28) The unit A is a unit derived from at least one compound selected from the group consisting of hydroxymethyl (meth) acrylate and hydroxyethyl (meth) acrylate, or a unit represented by the following formula (i) The composition for gel polymer electrolytes in any one of said (25)-(27):

(i).

(29) The composition for gel polymer electrolyte according to any one of (25) to (28), wherein Unit C is a unit represented by the following Chemical Formula 2a or Chemical Formula 2b:

[Formula 2a]

[Formula 2b]

Where

R 'is a linear or nonlinear 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, or a substituted or substituted carbon group having 6 to 20 carbon atoms or At least one selected from the group consisting of an unsubstituted arylene group, a substituted or unsubstituted biarylene group having 6 to 20 carbon atoms, a substituted or unsubstituted arylene group having 6 to 20 carbon atoms, a naphthalene group and an anthracene group.

(30) The composition for a gel polymer electrolyte according to any one of (25) to (29), wherein the unit E is a unit represented by the following formula (3):

[Formula 3]

Where

R ₁ and R ₂ are linear or nonlinear alkylene groups having 1 to 5 carbon atoms,

R ₃ and R ₄ are each independently one selected from the group consisting of hydrogen, an alkyl group having 1 to 5 carbon atoms, and a phenyl group,

R ₅ to R ₁₀ are each independently one selected from the group consisting of hydrogen, an alkyl group having 1 to 5 carbon atoms, a phenyl group, and fluorine,

o is an integer of 0 or 1,

p is 0 or an integer from 1 to 400,

r is an integer from 1 to 400,

The molar ratio of p: r is 0: 100 to 80:20.

(31) In any one of (25) to (30), wherein unit A is 1 mol or 2 mol in 1 mol of the first oligomer, and the molar ratio of unit C: unit E is 1.005: 1 to 2: 1. The composition for gel polymer electrolytes described.

(32) Any of (25) to (31), wherein the first oligomer optionally further includes at least one or more units selected from the group consisting of unit B represented by the following formula (4) and unit D represented by the following formula (5): The composition for gel polymer electrolytes of any one of Claims.

[Formula 4]

* -CO-R ''-O- *

[Formula 5]

* -O- [R '''-O] _m- *

Where

R '' is a substituted or unsubstituted linear alkylene group having 1 to 10 carbon atoms, or a substituted or unsubstituted nonlinear alkylene group having 1 to 10 carbon atoms,

R '' 'is a substituted or unsubstituted linear alkylene group having 1 to 10 carbon atoms, or a substituted or unsubstituted nonlinear alkylene group having 1 to 10 carbon atoms,

m is an integer of 1-30.

(33) The composition for a gel polymer electrolyte according to any one of (25) to (32), wherein the oligomer is represented by at least one selected from the group consisting of the following Chemical Formulas 6a to 6c.

[Formula 6a]

[A] _s- [B] _n- [CE-] _k -C- [B] _n -A

[Formula 6b]

[A] _s- [CDED] _k -CA

[Formula 6c]

[A] _s- [B] _n- [CDED] _k -C- [B] _n -A.

Where

n is 0 or an integer from 1 to 30,

k is an integer from 1 to 200,

s is 0 or 1.

(34) In 1 mol of the oligomer, unit A is 1 mol or 2 mol, and the molar ratio of unit B: unit C: unit D: unit E is 0 to 35: 2 to 201: 0 to 35: 1 to 200 (wherein Unit gel and electrolyte according to any one of (25) to (33), wherein units B and D are not 0 at the same time.

(35) The composition for a gel polymer electrolyte according to any one of (25) to (34), wherein the first oligomer is at least one compound selected from the group consisting of the following Formulas 7a to 7d.

[Formula 7a]

[Formula 7b]

[Formula 7c]

[Formula 7d]

Where

k is an integer from 1 to 200,

n is an integer from 1 to 30,

m is an integer from 1 to 30,

p is an integer from 1 to 400,

r is an integer from 1 to 400,

The molar ratio of p: r is 0: 100 to 80:20.

(36) The composition for gel polymer electrolyte according to any one of (25) to (35), wherein the polymer network further contains inorganic particles on the polymer network.

(37) The composition for gel polymer electrolyte according to any one of (25) to (36), wherein the weight average molecular weight of the oligomer is 1,000 to 100,000.

(38) The polymerization initiator is benzoyl peroxide, acetyl peroxide, dilauryl peroxide, di-tert- butyl peroxide, t- butyl peroxy-2-ethyl-hexanoate, cumyl hydroperoxide, hydrogen per Oxides, 2,2'-azobis (2-cyanobutane), 2,2'-azobis (methylbutyronitrile), AIBN (2,2'-Azobis (iso-butyronitrile)) and AMVN (2, 2'-Azobisdimethyl-Valeronitrile) The composition for gel polymer electrolytes in any one of said (25)-(37) which is a single substance or mixture of 2 or more types chosen from the group which consists of 2'-Azobisdimethyl-Valeronitrile).

(39) The composition for gel polymer electrolyte according to any one of (25) to (38), wherein the polymerization initiator is contained in an amount of 0.01% by weight to 2% by weight based on the total content of the oligomer.

(40) The lithium salt may be 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 ( The gel according to any one of (25) to (39), which is any one selected from the group consisting of CF ₃ SO ₂ ) ₃ , LiC ₄ BO ₈ , LiTFSI, LiFSI, and LiClO ₄ , or a mixture of two or more thereof. Polymer electrolyte composition.

(41) The composition for gel polymer electrolyte according to any one of (25) to (40), wherein the lithium salt contains 10 to 50% by weight based on the total content of the polymerization initiator and the oligomer.

(42) The composition for gel polymer electrolyte according to any one of (25) to (41), wherein the electrolyte solvent is a linear carbonate, a cyclic carbonate, or a combination thereof.

(43) The linear carbonate includes any one or a mixture of two or more selected from the group consisting of dimethyl carbonate, diethyl carbonate, dipropyl carbonate, ethylmethyl carbonate, methylpropyl carbonate and ethylpropyl carbonate, wherein the cyclic Carbonates are ethylene carbonate, propylene carbonate, 1,2-butylene carbonate, 2,3-butylene carbonate, 1,2-pentylene carbonate, 2,3-pentylene carbonate, vinylene carbonate, and halides thereof The composition for gel polymer electrolytes in any one of said (25)-(42) containing any 1 or 2 or more types of these selected from the group which consists of these.

(44) a positive electrode and a negative electrode capable of occluding and releasing lithium, and a polymer electrolyte disposed between the positive electrode and the negative electrode, wherein the polymer electrolyte is a gel polymer electrolyte according to any one of (1) to (22). Lithium secondary battery comprising a.

(45) The lithium secondary battery according to the above (44), wherein the charging voltage of the lithium secondary battery is 2.5V to 5.0V.

(46) An electrochromic device comprising a first electrode, a second electrode, an electrochromic material and the gel polymer electrolyte according to any one of (1) to (22).

The gel polymer electrolyte of the present invention includes a polymer network composed of an oligomer including urethane, acrylate, and siloxane, thereby improving mechanical strength together with ionic conductivity. Therefore, it is possible to manufacture a lithium secondary battery with improved lifetime characteristics and capacity characteristics. In addition, the gel polymer electrolyte of the present invention has the advantage that it can be used in both aqueous and non-aqueous cathode systems.

1 is a graph showing the charge and discharge test results according to Experimental Example 4.

Hereinafter, the present invention will be described in more detail to aid in understanding the present invention.

The terms or words used in this specification and claims are not to be construed as limiting in their usual or dictionary meanings, and the inventors may appropriately define the concept of terms in order to best explain their invention in the best way possible. It should be interpreted as meaning and concept corresponding to the technical idea of the present invention based on the principle that the present invention.

On the other hand, "*" means the moiety connected between the same or different atoms or terminal ends of the formula, unless otherwise specified in the present invention.

Specifically, one embodiment of the present invention

Polymer networks; And

An electrolyte impregnated on said polymer network,

The polymer network comprises a first oligomer comprising unit A derived from a monomer comprising at least one copolymerizable acrylate or acrylic acid, a unit C comprising urethane, and a unit E comprising siloxane in a three-dimensional structure. It provides a gel polymer electrolyte, characterized in that formed.

In general, the gel polymer electrolyte is not only weak in safety and mechanical properties compared to the solid polymer electrolyte, but also has a disadvantage in that ionic conductivity is lower than that of the liquid electrolyte. Therefore, recently, studies to improve mechanical properties and ionic conductivity using copolymers such as oligomers have been conducted. However, when the monomers are used alone, there is a problem in that deterioration of cycle characteristics and a desired level of mechanical characteristics cannot be obtained. In the case of using the oligomeric compound alone, it is not easy to control the physical properties, it is difficult to form a homogeneous polymer in the battery may be difficult to apply to the recent high capacity and large cells.

The present invention has been made to solve these problems by providing a gel polymer electrolyte comprising a polymer network formed by oligomer compounds prepared by polymerizing compounds having physical properties that can complement the electrochemical and mechanical properties.

In particular, in the case of gel polymer electrolytes containing terminal groups having the same polarity as the conventional acrylates, when applied to a non-aqueous negative electrode system using a non-aqueous binder such as PVDF, there is no great problem, but an aqueous binder such as CMC or SBR When used in an aqueous negative electrode system using the, there is a disadvantage that the ion conductivity is lowered by the resistance. Accordingly, the present invention provides a gel polymer electrolyte comprising an oligomer in which the ratio of the unit A derived from the monomer containing acrylic acid, the unit C containing urethane, the unit E containing siloxane, and the like is appropriately adjusted. In any situation, such as an aqueous system as well as an aqueous system, it is possible to prevent side reactions from occurring and lower the resistance to improve ion conductivity.

First, the first oligomer included in the gel polymer electrolyte of the present invention may be represented by the following Chemical Formula 1.

 [Formula 1]

A- [CE] _k -CA

Where

k is an integer of 1 to 200.

Specifically, in the implementation of the gel polymer electrolyte of the present invention, the unit A constituting the oligomer is a component that serves to form a gel polymer through a curing reaction in the oligomer, at least one carbon-oxygen single in the molecular structure As a derived unit derived from a monomer containing a mono- or polyfunctional (meth) acrylate containing a bond or acrylic acid, specifically 1 to 20, preferably 1 to 10 acrylate or methacrylate structures It may be a compound containing.

Specifically, the unit A constituting the oligomer is a unit derived from at least one compound selected from the group consisting of hydroxymethyl (meth) acrylate, and hydroxyethyl (meth) acrylate as a representative example thereof, or It may include a unit represented by).

(i).

In addition, in the implementation of the gel polymer electrolyte of the present invention, the unit C constituting the oligomer is a component for imparting a function of adjusting the ion transport characteristics, and controlling the mechanical properties and adhesion, specifically, to immobilize the anion of the salt It is a unit structure necessary to form a rigid structure in a molecule so as to secure the flexibility of the polymer.

Specifically, the unit C may be represented by the compound of Formula 2a or Formula 2b.

[Formula 2a]

[Formula 2b]

Where

R 'is a linear or nonlinear 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, or a substituted or substituted carbon group having 6 to 20 carbon atoms or At least one selected from the group consisting of an unsubstituted arylene group, a substituted or unsubstituted biarylene group having 6 to 20 carbon atoms, a substituted or unsubstituted arylene group having 6 to 20 carbon atoms, a naphthalene group and an anthracene group.

In this case, in the compound of Formula 2a or Formula 2b, R 'may include one selected from the group consisting of the following groups.

(Ri)

(R-ii)

(R-iii)

(R-iv)

(Rv)

(R-vi)

(R-vii)

(R-viii)

In addition, in the implementation of the gel polymer electrolyte of the present invention, the unit E constituting the oligomer is a component added to control the affinity between the mechanical properties and the separator, specifically, a rigid structural region by a urethane bond in the polymer structure In addition to forming a structure for securing flexibility, it is possible to increase the affinity with the polyolefin-based membrane fabric by using a low polarity. In particular, when the affinity with the polyolefin-based membrane fabric is improved, the resistance can be reduced to implement the effect of improving the ion conductivity more.

The unit E may be represented by the following formula (3).

[Formula 3]

Where

R ₁ and R ₂ are linear or nonlinear alkylene groups having 1 to 5 carbon atoms,

R ₃ and R ₄ are each independently one selected from the group consisting of hydrogen, an alkyl group having 1 to 5 carbon atoms, and a phenyl group,

R ₅ to R ₁₀ are each independently one selected from the group consisting of hydrogen, an alkyl group having 1 to 5 carbon atoms, a phenyl group, and fluorine,

o is an integer of 0 or 1,

p is 0 or an integer from 1 to 400,

r is an integer from 1 to 400,

The molar ratio of p: r is 0: 100 to 80:20.

Specifically, the unit E may include a compound selected from the group consisting of the following Chemical Formulas 3a to 3g.

 [Formula 3a]

[Formula 3b]

[Formula 3c]

[Formula 3d]

[Formula 3e]

[Formula 3f]

[Formula 3g]

Where

p is 0 or an integer from 1 to 400,

r is an integer from 1 to 400,

The molar ratio of p: r is 0: 100 to 80:20.

In addition, in forming the gel polymer electrolyte of the present invention, in one mole of the oligomer, unit A may be 1 mole or 2 moles, and the molar ratio of unit C to unit E may be about 1.005: 1 to 2: 1. . For example, when the k value is 200, the molar ratio of the unit C: E may be 201: 200, that is, 1.005: 1.

In addition, in implementing the gel polymer electrolyte of the present invention, the oligomer may further include at least one or more units selected from the group consisting of a unit B represented by the following formula (4) and a unit D represented by the following formula (5). .

[Formula 4]

* -CO-R ''-O- *

[Formula 5]

* -O- [R '''-O] _m- *

Where

R '' is a substituted or unsubstituted linear alkylene group having 1 to 10 carbon atoms, or a substituted or unsubstituted nonlinear alkylene group having 1 to 10 carbon atoms,

R '' 'is a substituted or unsubstituted linear alkylene group having 1 to 10 carbon atoms, or a substituted or unsubstituted nonlinear alkylene group having 1 to 10 carbon atoms,

m is an integer of 1-30.

In this case, the gel polymer electrolyte of the present invention further includes a unit D derived from the B unit and the oxyalkylene in the oligomer structure, thereby increasing dissociation of the salt in the polymer structure and affinity with the highly polar surface in the battery. You can implement the effect.

Specifically, the unit B is a unit for imparting the impregnation ability and the ion transport ability of the solvent, and may include at least one selected from the group consisting of the following groups.

* -CO-CH ₂ CH ₂ -O- * (Bi)

* -CO-CHCH ₃ CH ₂ -O- * (B-ii)

* -CO-CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ -O- * (B-iii)

* -CO-CHCH ₃ CH ₂ CH ₂ -O- * (B-iv)

In addition, the unit D is a unit for imparting a function for adjusting the impregnation ability, the electrode affinity, and the ion transfer ability of the solvent, and may include at least one selected from the group consisting of the following groups.

* -O-CH ₂ CH ₂ -O- * (Di)

* -O-CHCH ₃ CH ₂ -O- * (D-ii)

In addition, the oligomer included in the gel polymer electrolyte of the present invention may be represented by at least one selected from the group consisting of the following formulas 6a to 6c.

[Formula 6a]

[A] _s- [B] _n- [CE-] _k -C- [B] _n -A

[Formula 6b]

[A] _s- [CDED] _k -CA

[Formula 6c]

[A] _s- [B] _n- [CDED] _k -C- [B] _n -A.

Where

n is 0 or an integer from 1 to 30,

k is an integer from 1 to 200,

s is 0 or 1.

In 1 mol of such oligomer, unit A is 2 mol, and the molar ratio of unit B: unit C: unit D: unit E is 0-35: 2-201: 0-35: 1-200, specifically unit B: unit C: The molar ratio of unit D to unit E may be 0 to 35:10 to 100: 0 to 35:20 to 100, and more specifically 0 to 5:10 to 100: 10 to 30:20 to 100. , Units B and D do not go to zero at the same time.)

In the gel polymer electrolyte of the present invention, the oligomer may be at least one selected from the group consisting of the following Chemical Formulas 7a to 7d.

[Formula 7a]

[Formula 7b]

[Formula 7c]

[Formula 7d]

Where

k is an integer from 1 to 200,

n is an integer from 1 to 30,

m is an integer from 1 to 30,

p is an integer from 1 to 400,

r is an integer from 1 to 400,

The molar ratio of p: r is 0: 100 to 80:20.

The weight average molecular weight of the oligomer for forming the gel polymer electrolyte of the present invention may be about 1,000 to 100,000. When the weight average molecular weight of the oligomer is in the above range, it is possible to effectively improve the mechanical strength of the battery comprising the same.

In addition, the gel polymer electrolyte is methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, propyl methacrylate, butyl acrylate, butyl to further improve mechanical strength and curing effect. Methacrylate, hexyl acrylate, hexyl methacrylate, ethylhexyl acrylate, ethylhexyl methacrylate, 2,2,2-trifluoroethyl acrylate, 2,2,2-trifluoroethyl methacrylate A second oligomer comprising units derived from at least one selected from the group consisting of 2,2,3,3-tetrafluoropropyl acrylate, and 2,2,3,3-tetrafluoropropyl methacrylate. It may further include.

At this time, the second oligomer is preferably included in less than 50% by weight, specifically 20% by weight based on the total content of the first oligomer. If the content of the second oligomer exceeds 50% by weight, since the oligomer is contained in an excessive amount to increase resistance, a disadvantage may occur in that the cycle characteristics and the like decrease.

As described above, the gel polymer electrolyte of the present invention includes the unit E containing siloxane in the oligomer structure, thereby ensuring excellent mechanical properties of the gel polymer electrolyte and enhancing affinity with the polyolefin-based membrane fabric. Can be. In addition, as the affinity with the membrane fabric is improved, the resistance is reduced to improve the ion transfer characteristics, thereby realizing the effect of improving the ion conductivity more.

In addition, the gel polymer electrolyte of the present invention may include the urethane bond of the unit C, and the unit B and D selectively in the structure, thereby enhancing the effect of further ion transfer properties to realize the effect of improving the ion conductivity, as well as elasticity And by increasing the flexibility and the like can be relieved stress due to volume expansion generated when driving the battery. In addition, it is possible to secure additional heat resistance through the acrylic functional group of the unit A configured at the terminal, and effectively fix the electrolyte solution.

As described above, since the gel polymer electrolyte of the present invention has improved ion conductivity and does not need to reduce the thickness of the gel polymer electrolyte, sufficient mechanical strength can be ensured and the life characteristics of the secondary battery including the same can be improved. Can be.

In particular, the gel polymer electrolyte of the present invention comprises an oligomer in which the ratio of the unit A derived from the monomer containing acrylic acid, the unit C containing urethane, and the unit E containing siloxane, and the ratio of unit B and unit D are properly adjusted. By providing a gel polymer electrolyte comprising, it is possible to implement the effect of improving the ion conductivity by lowering the resistance in any situation, such as non-aqueous negative electrode system as well as the aqueous negative electrode system.

Meanwhile, in the gel polymer electrolyte of the present invention, the polymer network may further contain inorganic particles in the range of 10 to 25% by weight based on the total weight of the polymer network.

The inorganic particles may be impregnated in the polymer network to allow the high viscosity solvent to penetrate well through the pores formed by the void space between the inorganic particles. That is, by including the inorganic particles, it is possible to obtain an effect of further improving the wettability to a high viscosity solvent by affinity between the polar substances and capillary phenomenon.

As such inorganic particles, inorganic particles having a high dielectric constant and which do not generate an oxidation and / or reduction reaction in an operating voltage range of the lithium secondary battery (for example, 0 to 5V based on Li / Li ⁺ ) may be used.

Specifically, the inorganic particles are BaTiO ₃ , BaTiO ₃ , Pb (Zr, Ti) O ₃ (PZT), Pb _{1 - x} La _x Zr _{1 - y} Ti _y O ₃ (PLZT) having a dielectric constant of 5 or more as a representative example thereof. , Where 0 <x <1, 0 <y <1, Pb (Mg _1/3 Nb _2/3 ) O ₃ -PbTiO ₃ (PMN-PT), Hafnia (HfO ₂ ), SrTiO ₃ , SnO ₂ , CeO ₂ , MgO, NiO, CaO, ZnO, ZrO ₂ , Y ₂ O ₃ , Al ₂ O ₃ , TiO ₂ , SiC and a mixture selected from the group consisting of two or more thereof.

In addition, in addition to the inorganic particles, inorganic particles having lithium ion transfer ability, that is, lithium phosphate (Li ₃ PO ₄ ), lithium titanium phosphate (Li _x Ti _y (PO ₄ ) ₃ , 0 <x <2, 0 <y <3 ), Lithium aluminum titanium phosphate (Li _x Al _y Ti _z (PO ₄ ) ₃ , 0 <x <2, 0 <y <1, 0 <z <3), 14Li ₂ O-9Al ₂ O ₃ -38TiO _2- (LiAlTiP) such as 39P ₂ O _{5 x} O _y series glass (0 <x <4, 0 <y <13), lithium lanthanum titanate _{(Li x La y TiO 3,} 0 <x <2, 0 <y < 3), Li _{3 . 25 Ge 0 .25 P 0. 75 S} 4 Mani lithium germanium thiophosphate Titanium _{(Li x Ge y P z S} w, 0 <x <4, 0 <y <1, 0 <z <1, 0 <w such as <5), lithium nitride such as Li ₃ N (Li _x N _y , 0 <x <4, 0 <y <2), SiS ₂ series glass such as Li ₃ PO ₄ -Li ₂ S-SiS ₂ (Li P ₂ S ₅ series glass (Li _x P _y S _z , 0, such as _x Si _y S _z , 0 <x <3, 0 <y <2, 0 <z <4), LiI-Li ₂ SP ₂ S _5, etc. <x <3, 0 <y <3, 0 <z <7) or mixtures thereof, and the like.

The average particle diameter of the inorganic particles is preferably in the range of about 0.001 to 10 ㎛ in order to have a proper porosity in a uniform thickness in the gel polymer electrolyte. If the average particle size is less than 0.001㎛ dispersibility may be lowered, if the average particle diameter is more than 10㎛ not only can increase the thickness of the porous coating layer, but also agglomeration of inorganic particles occurs gel polymer electrolyte Exposure to the outside can lower the mechanical strength.

As described above, the gel polymer electrolyte of the present invention is 1.0x10 ^-4 S / cm than in the case of measuring the impedance measurement analysis system at 25 ℃ temperature, specifically, 1.0x10 ^-4 S / cm to 2.0x10 ^-2 S / It may have a Li ⁺ ion conductivity of cm.

At this time, the ion conductivity was measured using the Impedance measurement method in the form of a SUS / GPE / SUS cell to form a gel polymer electrolyte film of 13mm thickness. The measuring equipment is Bio Logic's VMP3 model, and the measurement conditions were performed at room temperature under 10,000-0.1Hz and 10mV amplitude conditions.

In addition, the gel polymer electrolyte may have a Li ⁺ ion transfer coefficient of 0.3 or more based on NMR measurement at a temperature of 25 ℃. In this case, the Li ⁺ ion mobility factor is Li ⁺ ion diffusion also / can be defined as (Li ⁺ ion diffusivity + anion diffusivity), in which the Li ⁺ ion diffusivity and anion diffusivity is the following equipment and methods Can be measured.

For example, a Varian 500 MHz NMR / dual probe was used, and Li ⁺ cation diffusion constant was measured by ⁷ Li diffusion NMR, and anion diffusion was measured by ¹⁹ F diffusion NMR. The solvent used was acetone-d ₆ , and the inner tube (acetone-d ₆ ) was used to prevent the sample from mixing with the deuterium solvent to measure the diffusion value in the sample itself. In this measurement experiment, the pulse sequence was stimulated echo with gradient pulse. Gradient amplitude was adjusted so that the peak intensity at the highest gradient power was about 2 to 5% of the peak intensity at the lowest gradient power. This section was divided into 16 steps in the same way as the solution NMR. Different amplitudes were applied.

In addition, the gel polymer electrolyte may have a gel content of about 1% by weight or more, specifically about 20% by weight or more at 25 ° C.

In addition, the gel polymer electrolyte preferably has an unreacted oligomer content of 20% or less relative to the total amount of the reactive oligomer at 25 ° C.

In this case, the content of the unreacted oligomer may be implemented by implementing a gel polymer electrolyte, then extracting the gel polymer electrolyte with a solvent (acetone), and then checking the extracted solvent through NMR measurement.

On the other hand, in the gel polymer electrolyte of the present invention, the electrolyte is composed of a conventional lithium salt-containing non-aqueous solvent, wherein the lithium salt is 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 (CF ₃ SO ₂ ) ₃ , LiC ₄ BO ₈ , LiTFSI, LiFSI, and LiClO ₄ Or a mixture of two or more thereof, but is not limited thereto.

The lithium salt may include 10 to 50% by weight based on the total content of the polymerization initiator and the oligomer.

In addition, as the electrolyte solvent of the present invention, a non-aqueous solvent commonly used in a lithium secondary battery electrolyte may be used. For example, ether, ester (Acetate, Propionate), amide, linear carbonate or cyclic carbonate, nitrile (aceto Nitrile, SN, and the like) may be used alone or in combination of two or more thereof.

Among them, carbonate compounds which are typically cyclic carbonates, linear carbonates or mixtures thereof may be included.

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

In particular, propylene carbonate and ethylene carbonate, which are cyclic carbonates in the carbonate electrolyte solvent, may be preferably used because they have high dielectric constants and dissociate lithium salts in the electrolyte well, such as ethylmethyl carbonate and diethyl carbonate. Alternatively, when a low viscosity, low dielectric constant linear carbonate such as dimethyl carbonate is mixed and used in an appropriate ratio, an electrolyte having high electrical conductivity can be made, and thus it can be used more preferably.

In addition, the ester in the electrolyte solvent is methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, γ-butyrolactone, γ-valerolactone, γ-caprolactone, α-valerolactone And ε-caprolactone, but any one selected from the group consisting of, or a mixture of two or more thereof may be used, but is not limited thereto.

In addition, the electrolyte solvent may improve the performance by adding a conventional additive used in the electrolyte solution. For example, VC, VEC, Propane sultone, SN, 'AdN, ESa, PRS, FEC, LiPO ₂ F ₂ , LiODFB, LiBOB, TMSPa, TMSPi, TFEPa, TFEPi may further include without limitation.

In the conventional general electrolyte solution, the metal ions eluted from the positive electrode are precipitated at the negative electrode, whereas the gel polymer electrolyte of the present invention includes a polymer network formed by the oligomer, thereby combining with the metal ions eluted at the positive electrode to precipitate the metal at the negative electrode. I can alleviate it. Therefore, the charge and discharge efficiency of the lithium secondary battery can be improved and good cycle characteristics can be exhibited. In addition, by forming a protective layer composed of a polymer on the surface of the positive electrode and the negative electrode, or by using a polymer structure to suppress side reactions through anion stabilization and to increase the adhesion between the electrodes can suppress the gas generation inside the battery at a high temperature. In addition, it may be possible to improve the stability of the membrane through the polymer polymer, thereby improving the stability through penetration, such as through charging stability, flame retardancy and reduced volatility.

In the present invention,

Unit A derived from monomers comprising at least one copolymerizable acrylate or acrylic acid;

Unit C comprising urethane; And

A gel polymer electrolyte comprising unit E comprising siloxane can be provided.

In the present invention,

An oligomer comprising unit E comprising a siloxane,

Li ⁺ ion conductivity of 1.0x10 ^-4 S / cm to 2.0x10 ^-2 S / cm at a temperature of 25 ℃,

Li ⁺ ion transfer coefficient of 0.3 or more, and

It is possible to provide a gel polymer electrolyte having a content of unreacted oligomer of 20% or less relative to the total amount of reactive oligomer.

In addition, another embodiment of the present invention

Lithium Salt,

Electrolyte solvent,

Polymerization initiator, and

Provided is a composition for a gel polymer electrolyte of the present invention comprising an oligomer comprising a unit A derived from a monomer comprising at least one copolymerizable acrylate or acrylic acid, a unit C comprising a urethane, and a unit E comprising a siloxane. can do.

In this case, the oligomer may be included in 0.5% by weight to 20% by weight, more preferably 0.5% by weight to 10% by weight relative to the total weight of the composition for the gel polymer electrolyte. If less than 0.5% by weight of the gel polymer is difficult to be difficult to express the characteristics of the gel polymer electrolyte, if it exceeds 20% by weight may increase the resistance due to the excessive content of the oligomer may lower the battery performance.

At this time, in the present invention, the gel polymer electrolyte of the present invention can be produced from the gel polymer electrolyte composition using a polymerization method known in the art.

The polymerization initiator used for this reaction may be used conventional polymerization initiator known in the art.

Non-limiting examples of the polymerization initiator are benzoyl peroxide, acetyl peroxide, dilauryl peroxide, di-tert-butyl peroxide, organic peroxides and hydros such as t-butyl peroxy-2-ethyl-hexanoate, cumyl hydroperoxide, and hydrogen peroxide Peroxides with 2,2'-azobis (2-cyanobutane), 2,2'-azobis (methylbutyronitrile), AIBN (2,2'-Azobis (iso-butyronitrile)) and AMVN (2 And azo compounds such as 2'-Azobisdimethyl-Valeronitrile), but are not limited thereto.

The polymerization initiator is decomposed by heat in a battery, such as, but not limited to, 30 ° C. to 100 ° C., or decomposed at room temperature (5 ° C. to 30 ° C.) to form radicals, and the polymerizable oligomer is acrylate by free radical polymerization. The gel polymer electrolyte may be formed by reacting with the compound.

In addition, the polymerization initiator may be used in an amount of 0.01% by weight to 2% by weight based on the total content of the oligomer. If the polymerization initiator is more than 2% by weight, gelation may occur too quickly or the unreacted initiator remains after the gel polymer electrolyte composition is injected into the battery, which adversely affects the battery performance. Conversely, the polymerization initiator is less than 0.01 part by weight. There is a problem that the gelation is not made well.

Gel polymer electrolyte composition according to an embodiment of the present invention, in addition to the components described above, in order to impart an effect of increasing the efficiency and resistance of the gel reaction, and optionally other additives that can implement such properties known in the art It may contain more.

The gel polymer electrolyte may be improved by adding a conventional additive used in an electrolyte solution. For example, general additives such as VC, VEC, Propane sultone, SN, 'AdN, ESa, PRS, FEC, LiPO ₂ F ₂ , LiODFB, LiBOB, TMSPa, TMSPi, TFEPa, TFEPi are applicable.

In another embodiment of the present invention

A positive electrode and a negative electrode capable of occluding and releasing lithium, and a polymer electrolyte disposed between the positive electrode and the negative electrode,

It provides a lithium secondary battery comprising the gel polymer electrolyte of the present invention as the polymer electrolyte.

The gel polymer electrolyte is formed by polymerizing the composition for gel polymer electrolyte according to a conventional method known in the art. For example, the gel polymer electrolyte may be formed by in-situ polymerization of the composition for gel polymer electrolyte in the secondary battery.

For a more preferred embodiment, (a) inserting an electrode assembly consisting of a positive electrode, a negative electrode and a separator interposed between the positive electrode and the negative electrode in the battery case and (b) the present invention in the battery case Injecting the composition for the gel polymer electrolyte according to the polymerization may include the step of forming a gel polymer electrolyte.

In -situ polymerization reaction in the lithium secondary battery is possible through the E-BEAM, gamma rays, room temperature / high temperature aging process, according to one embodiment of the present invention can be carried out through thermal polymerization. At this time, the polymerization time takes about 2 minutes to 12 hours, the thermal polymerization temperature may be 30 to 100 ℃.

More specifically, in-situ polymerization reaction in a lithium secondary battery is added to a predetermined amount of the initiator and the oligomer in an electrolyte solution containing a lithium salt and mixed and then injected into a battery cell. After sealing the injection port of such a battery cell, the polymerization is carried out by heating to 40 to 80 ℃ for 1 to 20 hours, the gel polymer electrolyte contained in the form of a gel is prepared when the lithium salt-containing electrolyte is subjected to gelation.

The lithium secondary battery according to an embodiment of the present invention has a charge voltage of 3.0V to 5.0V, excellent capacity characteristics of the lithium secondary battery in both the normal voltage and the high voltage region.

On the other hand, according to an embodiment of the present invention, the electrode constituting the lithium secondary battery can be manufactured by a conventional method known in the art. For example, a slurry may be prepared by mixing and stirring a solvent, a binder, a conductive material, and a dispersant in an electrode active material, and then applying the coating (coating) to a current collector of a metal material, compressing, and drying the electrode to prepare an electrode. have.

According to an embodiment of the present invention, the positive electrode active material constituting the positive electrode may be applied to a general voltage or a high voltage, and a compound capable of reversibly intercalating / deintercalating lithium may be used.

Specifically, the positive electrode active material is, for example, LiCoO ₂ , LiNiO ₂ , LiMnO ₂ , LiMn ₂ O ₄ , LiNi _{1 - y} Co _y O ₂ (O = y <1), LiCo _{1 - y} Mn _y O ₂ ( O = y <1), LiNi _{1 - y} Mn _y O ₂ (O = y <1), and Li [Ni _a Co _b Mn _c ] O ₂ (0 <a, b, c = 1, a + b + c = 1) may include any one or a mixture of two or more thereof selected from the group consisting of It is not limited to these. In addition to these oxides, sulfides, selenides and halides may also be included.

In addition, according to an embodiment of the present invention, as the negative electrode active material constituting the negative electrode, a carbon material, lithium metal, silicon, tin, or the like, into which lithium ions may be inserted and released, may be used. Preferably, a carbon material may be used, and as the carbon material, both low crystalline carbon and high crystalline carbon may be used. Soft crystalline carbon and hard carbon are typical low crystalline carbon, and high crystalline carbon is natural graphite, Kish graphite, pyrolytic carbon, liquid crystal pitch carbon fiber. High temperature calcined carbon such as (mesophase pitch based carbon fiber), meso-carbon microbeads, Mesophase pitches and petroleum or coal tar pitch derived cokes.

The positive electrode and / or negative electrode may be prepared by mixing and stirring a binder, a solvent, a conductive material and a dispersant, which may be commonly used as necessary, to prepare a slurry, and then applying the same to a current collector and compressing the negative electrode.

The binder may be polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-co-HEP), polyvinylidene fluoride (polyvinylidenefluoride), polyacrylonitrile, polymethylmethacrylate, Polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene, polypropylene, polyacrylic acid, ethylene-propylene-diene monomer (EPDM), Various kinds of binder polymers such as sulfonated EPDM, styrene butyrene rubber (SBR), fluorine rubber, various copolymers and the like may be used.

In addition, the lithium secondary battery may have a separator between the positive electrode and the negative electrode according to the type. As such a separator, a conventional porous polymer film, that is, polyethylene, polypropylene, polyvinylidene fluoride or two or more multilayer films thereof may be used, and a polyethylene / polypropylene two-layer separator and a polyethylene / polypropylene / polyethylene three-layer separator Of course, a mixed multilayer film such as polypropylene / polyethylene / polypropylene three-layer separator can be used. Or a conventional porous non-woven fabric, for example, a non-woven fabric made of glass fibers of high melting point, polyethylene terephthalate fibers and the like can be used, but is not limited thereto.

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

On the other hand, in another embodiment of the present invention

A first electrode, a second electrode, an electrochromic material, and

It is also possible to further provide an electrochromic device comprising the gel polymer electrolyte of the present invention.

In this case, the first electrode and the second electrode may have a structure in which a transparent conductive layer is formed on a substrate, and the electrochromic device may include a flexible substrate and a rigid substrate on opposite surfaces of the electrolyte.

As such, when the gel polymer electrolyte of the present invention is applied for flexibility and durability of the color change device and freedom of design, it is possible to secure ion conductivity and durability required for driving the device.

In this case, the substrate and the transparent conductive layer are not particularly limited as long as they are known in the art. Examples of the substrate include glass and transparent plastics (polymer), and conductive materials for forming the transparent conductive layer include indium doped tin oxide (ITO), antimony doped tin oxide (ATO), and fluorine doped tin oxide (FTO). ), IZO (Indium doped zinc oxide), ZnO and the like. The conductive material may be deposited on the substrate by a known method such as sputtering, electron beam deposition, chemical vapor deposition, or sol-gel coating to form a transparent conductive layer.

In addition, the kind of electrochromic material is not particularly limited, and inorganic metal oxides such as WO ₃ , Ir (OH) x, MoO ₃ , V ₂ O ₅ , TiO ₂ , NiO; Conductive polymers such as polypyrrole, polyaniline, polyazulene, polypyridine, polyindole, polycarbazole, polyazine and polythiophene; Organic discoloring substances, such as viologen, anthraquinone, and phenocyazine, etc. are mentioned.

The method of laminating the electrochromic material on the electrode is not particularly limited as long as it can form a thin film at a constant height from the base surface along the surface profile, and examples thereof include vacuum deposition methods such as sputtering.

Among the electrochromic materials, for example, WO ₃ is a material that is colored by a reduction reaction, and NiO is a material that is colored by an oxidation reaction. The electrochemical mechanism in which the electrochromic device occurs in the electrochromic device including the inorganic metal oxide is described as in Scheme 1. Specifically, when voltage is applied to the electrochromic device, protons (H ⁺ ) or lithium ions (Li ⁺ ) contained in the electrolyte are inserted into or desorbed from the electrochromic material according to the polarity of the current. In order to satisfy, by changing the oxidation number of the transition metal contained in the electrochromic material, the optical properties of the electrochromic material itself, such as transmittance (color), is changed.

Scheme 1

WO ₃ (transparent) + xe + xM M _x WO ₃ (dark blue)

Wherein M is a proton or an alkali metal cation such as Li ⁺ .

The electrochromic device configured as described above may be manufactured according to a conventional method known in the art, such as (a) preparing a first electrode and a second electrode; (b) injecting and then sealing the gel polymer electrolyte composition according to the present invention between the prepared first and second electrodes; And (c) polymerizing the injected electrolyte composition to form a gel polymer electrolyte.

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

EXAMPLE

Preparation of gel polymer electrolyte composition

(Example 1)

Ethylene carbonate (EC): ethyl methyl carbonate (EMC): dimethyl carbonate (DMC) = 2: 3: 5 (volume ratio) LiPF ₆ was dissolved in a non-aqueous electrolyte solvent to a concentration of 1 M to prepare an electrolyte solution. The oligomer of Formula 7a (molecular weight 7,800, unit A is 2 mol, unit B: unit C: unit D: mole ratio of unit E is 4.7: 33.4: 14.3: 47.6) 5% and AIBN as the polymerization initiator 0.5 to the total content of the oligomer A composition for gel polymer electrolyte was prepared by adding weight% and 0.5% VC.

(Example 2)

Ethylene carbonate (EC): ethyl methyl carbonate (EMC): dimethyl carbonate (DMC) = 2: 3: 5 (volume ratio) LiPF ₆ was dissolved in a non-aqueous electrolyte solvent to a concentration of 1 M to prepare an electrolyte solution. 5% of the oligomer of Formula 7b (molecular weight 8,500, unit A is 2 mol, unit C: unit D: mole ratio of unit E is 30:26:44) and 0.5 wt% of the total oligomer content of AIBN as a polymerization initiator, VC 0.5 % Was added to prepare a gel polymer electrolyte composition.

(Example 3)

Ethylene carbonate (EC): ethyl methyl carbonate (EMC): dimethyl carbonate (DMC) = 2: 3: 5 (volume ratio) LiPF ₆ was dissolved in a non-aqueous electrolyte solvent to a concentration of 1 M to prepare an electrolyte solution. 5% of the oligomer of Chemical Formula 7c (molecular weight 8,500, unit A is 1 mol, unit C: unit D: molar ratio of unit E is 30: 26:44) and 0.5 wt% VC 0.5% of the total content of the oligomer as the polymerization initiator Was added to prepare a composition for a gel polymer electrolyte.

(Example 4)

Ethylene carbonate (EC): ethyl methyl carbonate (EMC): dimethyl carbonate (DMC) = 2: 3: 5 (volume ratio) LiPF ₆ was dissolved in a non-aqueous electrolyte solvent to a concentration of 1 M to prepare an electrolyte solution. The oligomer of Formula 7d (molecular weight 8,100, unit A is 2 moles, unit B: unit C: unit D: mole ratio of unit E is 4.7: 33.4: 14.3: 47.6) 5% and AIBN as the polymerization initiator 0.5 to the total content of the oligomer A composition for gel polymer electrolyte was prepared by adding 0.5% by weight of VC.

(Example 5)

A gel polymer electrolyte composition was prepared in the same manner as in Example 1, except that 12% of the oligomer of Chemical Formula 7a was included.

(Example 6)

Ethylene carbonate (EC): ethyl methyl carbonate (EMC): dimethyl carbonate (DMC) = 2: 3: 5 (volume ratio) LiPF ₆ was dissolved in a non-aqueous electrolyte solvent to a concentration of 1 M to prepare an electrolyte solution. 5% oligomer (A is 2 mol, molar ratio of C: E is 1: 1, average molecular weight 10,000) 5% and 0.5% by weight of VC 0.5% to the total content of the oligomer was added as a polymerization initiator to prepare a gel polymer electrolyte composition. .

(Comparative Example 1)

Ethylene carbonate (EC): ethyl methyl carbonate (EMC): dimethyl carbonate (DMC) = 2: 3: 5 (volume ratio) LiPF ₆ was dissolved in a non-aqueous electrolyte solvent to a concentration of 1 M to prepare an electrolyte solution.

Subsequently, in the units constituting the oligomer of the present invention as an oligomer, the unit C containing urethane and the unit E including siloxane, instead of the dipentaerythritol containing only unit A derived from the monomer including acrylate A gel polymer electrolyte composition was prepared in the same manner as in Example 1, except that an oligomer made of pentaacrylate (dipentaerythritol pentaacrylate) was used.

(Comparative Example 2)

Ethylene carbonate (EC): ethyl methyl carbonate (EMC): dimethyl carbonate (DMC) = 2: 3: 5 (volume ratio) LiPF ₆ was dissolved in a non-aqueous electrolyte solvent to a concentration of 1 M to prepare an electrolyte solution.

Subsequently, instead of including the unit E containing siloxane among the units constituting the oligomer of the present invention as an oligomer, a unit A derived from a monomer containing acrylate and a unit C including urethane are represented by the following Chemical Formula 8 Except for using the oligomer to prepare a composition for a gel polymer electrolyte in the same manner as in Example 1.

[Formula 8]

Manufacture of Secondary Battery

(Example 7)

As a cathode active material _{(LiNi 1/3 Co 1/} 3 Mn 1/3 O 2; NCM) 94 % by weight, of a conductive material of carbon black (carbon black) 3% by weight, solvent: 3% by weight of PVdF as a binder, N- methyl A positive electrode mixture slurry was prepared by adding to 2-pyrrolidone (NMP). The positive electrode mixture slurry was applied to a thin film of aluminum (Al), which is a positive electrode current collector having a thickness of about 20 μm, dried to prepare a positive electrode, and then subjected to roll press to prepare a positive electrode.

A 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 at 96 wt%, 3 wt%, and 1 wt%, respectively, to NMP as a solvent. The negative electrode mixture slurry was applied to a copper (Cu) thin film, which is a negative electrode current collector having a thickness of 10 μm, dried to prepare a negative electrode, and then roll-rolled to prepare a negative electrode.

The battery was assembled using a separator consisting of the positive electrode, the negative electrode, and three layers of polypropylene / polyethylene / polypropylene (PP / PE / PP), and the gel polymer electrolyte composition prepared in Example 1 was injected into the assembled battery. After leaving for 2 days and then heated to 70 ℃ for 5 hours to prepare a secondary battery containing a gel polymer electrolyte.

(Example 8)

A secondary battery including the gel polymer electrolyte was manufactured in the same manner as in Example 7, except that the gel polymer electrolyte composition of Example 2 was injected instead of the gel polymer electrolyte composition of Example 1.

(Example 9)

A secondary battery including the gel polymer electrolyte was manufactured in the same manner as in Example 7, except that the gel polymer electrolyte composition of Example 5 was injected instead of the gel polymer electrolyte composition of Example 1.

(Example 10)

A secondary battery including the gel polymer electrolyte was manufactured in the same manner as in Example 7, except that the gel polymer electrolyte composition of Example 6 was injected instead of the gel polymer electrolyte composition of Example 1.

(Comparative Example 3)

A secondary battery including the gel polymer electrolyte was manufactured in the same manner as in Example 7, except that the gel polymer electrolyte composition of Comparative Example 1 was injected instead of the gel polymer electrolyte composition of Example 1.

(Comparative Example 4)

A secondary battery including a gel polymer electrolyte was manufactured in the same manner as in Comparative Example 3 except that the gel polymer electrolyte composition of Comparative Example 2 was injected instead of the composition for gel polymer electrolyte of Comparative Example 1.

Experimental Example 1 Measurement of Ion Conductivity

The gel polymer electrolyte composition prepared in Examples 1, 2, 5, and 6 and the gel polymer electrolyte composition prepared in Comparative Example 1 were prepared in the form of a film of 13 mm thickness, and then SUS / GPE / SUS cells. In the form, Li ⁺ ion conductivity was measured using Impedance measurement. The measuring instrument is Bio Logic's VMP3 model, and the measurement conditions were performed at room temperature (25 ℃) under 10,000-0.1Hz and 10mV amplitude conditions. The results are shown in Table 1 below.

	Ion conductivity
Example 1	8.4mS / cm
Example 2	8.1mS / cm
Example 5	6.5mS / cm
Example 6	4.8mS / cm
Comparative Example 1	7.0mS / cm

As shown in Table 1, when using the gel polymer electrolyte composition prepared in Examples 1 and 2 of the present invention, compared to the gel polymer electrolyte composition of Comparative Example 1 containing a conventional acrylate oligomer It can be seen that more than 10% improvement. In addition, when the content of the oligomer exceeds 10% as in Example 5, it can be seen that the ionic conductivity is increased by about 25% or more compared to the composition for gel polymer electrolyte in Example 6.

However, in Example 6, it was found that the ionic conductivity is lower than in Example 1.

From these results, it can be seen that when the molar ratio of the units forming the oligomer is properly included as in the present invention, the ion conductivity can be improved compared to the conventional gel polymer electrolyte.

Experimental Example 2

In the gel polymer electrolyte composition prepared in Examples 1, 2, 5, and 6 and Comparative Example 1, the inner tube for NMR measurement was added, the GPE was polymerized on the outer side of the inner tube, and then acetone-d6 was added to the inner tube. After the addition, the Li ⁺ ion transfer coefficient was measured using the following measuring method. The results are shown in Table 2 below.

[How to measure]

Li ⁺ ion migration coefficient = Li ⁺ ion diffusivity / (Li ⁺ ion diffusivity + anion diffusivity)

NMR Instruments: Varian 500MHz NMR / dual probe

Li ⁺ ion diffusivity: measured by ⁷ Li diffusion NMR

< ⁷ Li diffusion NMR experimental conditions>

Diffusion gradient length: 4.0 msec

-Diffusion delay: 200.0 msec

-Lowest gradient value: 100

Highest gradient value: 30000

-Number of increments: 16

Anion Diffusion: Measured by ¹⁹ F diffusion NMR.

< ¹⁹ F diffusion NMR test conditions>

Diffusion gradient length: 3.0 msec

-Diffusion delay: 70.0 msec

-Lowest gradient value: 1000

Highest gradient value: 23000

-Number of increments: 16

Solvent used: acetone-d ₆ (In this case, the inner tube (acetone-d ₆ ) was used to prevent the sample from mixing with the deuterium solvent to measure the diffusion value in the sample itself.)

pulse sequence: stimulated echo with gradient pulse

Gradient amplitude: The peak intensity at the highest gradient power is adjusted to be about 2 to 5% of the peak intensity at the lowest gradient power. This section is divided into 16 steps in the same manner as the solution NMR. Different amplitudes were applied.

Gel polymer electrolyte composition	Li + ion transfer coefficient
Example 1	0.435
Example 2	0.420
Example 5	0.382
Example 6	0.310
Comparative Example 1	0.402

As shown in Table 2, in the case of using the gel polymer electrolyte composition prepared in Examples 1 and 2 of the present invention, Li compared to the gel polymer electrolyte composition of Comparative Example 1 containing an existing acrylate oligomer ^{+ It} can be seen that the ion transfer coefficient is improved by about 4% or more.

In addition, even when the content of the oligomer exceeds 10% as in Example 5, it can be seen that the Li ⁺ ion transfer coefficient increased by about 15% or more compared to the gel polymer electrolyte composition in Example 6.

However, in Example 6, it can be seen that the Li ⁺ ion transfer coefficient is lower than in Example 1.

From these results, it can be seen that when the molar ratio of the units forming the oligomer is included as appropriate in the present invention, the Li ⁺ ion transfer coefficient can be improved compared to the conventional gel polymer electrolyte.

Experimental Example 3

After implementing the gel polymer electrolyte in the secondary batteries prepared in Examples 7 to 10 and Comparative Example 3, the gel polymer electrolyte was extracted with a solvent (acetone). Then, the extracted solvent was analyzed by the NMR measurement of the remaining amount of unreacted oligomer. The results are shown in Table 3 below.

Secondary battery	Unreacted oligomer (% by weight)
Example 7	N.D
Example 8	0.5%
Example 9	N.D
Example 10	2%
Comparative Example 3	3.0%

As shown in Table 3, the content of the unreacted oligomer of the secondary batteries of Examples 7 to 10 is 2% or less, while the content of the unreacted oligomer of the secondary battery of Comparative Example 3 is 3% and the content of the unreacted oligomer is 3%. It is high.

On the other hand, when the content of the unreacted oligomer is high, side reactions and resistance in the gel polymer electrolyte are increased, which may lower the cycle life characteristics of the secondary battery.

From this, it can be seen that the secondary batteries of Examples 7 to 10 have a lower side reaction and resistance than the secondary batteries of Comparative Example 3, thereby improving cycle life characteristics of the batteries.

(Experimental example 4: charge and discharge experiment)

For the secondary battery cells (design capacity 760mAh) and the secondary battery of Comparative Example 3 prepared in Examples 7 to 10 and constant current charge until the voltage reaches 4.15V at 1.0C, and then the current is reduced at the voltage Constant voltage charging was performed until it reached 1 / 20C. It was then discharged with constant current at 1.0C until the voltage reached 2.5V. The charging and discharging was repeated 100 times.

From the above results, the capacity retention rate was calculated using the following equation, and the results are shown in Table 4 and FIG. 1.

<Expression>

Capacity maintenance rate at 100th cycle = 100th cycle discharge capacity / 1st cycle discharge capacity

	1 st cycle discharge capacity	100 th cycle discharge capacity	Capacity retention at 100 th cycles (%)
Example 7	754 mAh	739 mAh	98%
Example 8	751 mAh	728 mAh	97%
Example 9	730 mAh	715 mAh	98%
Example 10	683 mAh	417 mAh	61%
Comparative Example 3	720 mAh	117 mAh	16.2%

As shown in Table 4, it can be seen that the secondary batteries of Examples 7 to 10, particularly the secondary batteries of Examples 7 and 8, have better capacity retention rates during charging and discharging than secondary batteries of Comparative Example 3.

Experimental Example 5

For each gel polymer electrolyte composition prepared in Example 1 and Comparative Example 2, the surface tension was measured at 25 ° C. using a ring method (a tensiometer K11 model device manufactured by KRUSS). The results are shown in Table 5 below.

	Surface tension (mN / m)
Example 1	29mN / m
Comparative Example 2	21mN / m

As shown in Table 5, in the case of the gel polymer electrolyte of the present invention including the oligomer including the units B, C, D and E, the comparative example 2 of the comparative example including an oligomer containing an acrylate unit and a urethane unit It can be seen that the surface tension is higher than that of the gel polymer electrolyte.

As a result, in the case of the gel polymer electrolyte including the oligomer of the present invention, in particular, the oligomer including the unit E, the affinity with the separator can be improved due to the high surface tension, thereby reducing the resistance and improving the ion conductivity. It can be expected that the improvement of cycle life characteristics can be realized.

Experimental Example 6

The cell including the gel polymer electrolyte prepared in Example 7 and Comparative Example 4 was decomposed to separate the separator containing the gel polymer electrolyte, and then the separated separator was placed in a chamber at 60 ° C. and 120 ° C. for about 30 minutes. After leaving for a minute, the degree of shrinkage of the membrane before and after the heat treatment was compared. The results (ratios) are shown in Table 6 below.

	Membrane Area (cm 2 )
	25 ℃	60 ℃	120 ℃
Example 7	20.52	19.76	19.38
Comparative Example 4	20.52	14.82	11.55

As shown in Table 6, in the case of the membrane impregnated with the gel polymer electrolyte of the present invention, it can be seen that the degree of shrinkage of the membrane at a high temperature is lower than that of the separator impregnated with the gel polymer electrolyte of Comparative Example 4. From these results, it can be predicted that the gel polymer electrolyte of the present invention is improved in durability at high temperature, thereby improving the life characteristics of the secondary battery.

Claims (46)

1. Polymer networks; And

   An electrolyte impregnated on said polymer network,

   The polymer network comprises a first oligomer comprising unit A derived from a monomer comprising at least one copolymerizable acrylate or acrylic acid, a unit C comprising urethane, and a unit E comprising siloxane in a three-dimensional structure. Gel polymer electrolyte, characterized in that formed.
2. The method according to claim 1,

   Gel polymer electrolyte, characterized in that the first oligomer is represented by the following formula (1):

   [Formula 1]

   A- [CE] _k -CA

   Where

   k is an integer of 1 to 200.
3. The method according to claim 1,

   Unit A is a unit derived from at least one compound selected from the group consisting of hydroxymethyl (meth) acrylate and hydroxyethyl (meth) acrylate, or a unit represented by the following formula (i) Gel polymer electrolyte:

   

   (i).
4. The method according to claim 1,

   The unit C is a gel polymer electrolyte, characterized in that it comprises a unit represented by the formula (2a) or (2b):

   [Formula 2a]

   

   [Formula 2b]

   

   Where

   R 'is a linear or nonlinear 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, or a substituted or substituted carbon group having 6 to 20 carbon atoms or At least one selected from the group consisting of an unsubstituted arylene group, a substituted or unsubstituted biarylene group having 6 to 20 carbon atoms, a substituted or unsubstituted arylene group having 6 to 20 carbon atoms, a naphthalene group and an anthracene group.
5. The method according to claim 4,

   The gel polymer electrolyte, characterized in that R 'is one compound selected from the group consisting of:

   

   (Ri)

   

   (R-ii)

   

   (R-iii)

   

   (R-iv)

   

   (Rv)

   

   (R-vi)

   

   (R-vii)

   

   (R-viii)
6. The method according to claim 1,

   The gel polymer electrolyte, characterized in that the unit E comprises a unit represented by the following formula (3):

   [Formula 3]

   

   Where

   R ₁ and R ₂ are linear or nonlinear alkylene groups having 1 to 5 carbon atoms,

   R ₃ and R ₄ are each independently one selected from the group consisting of hydrogen, an alkyl group having 1 to 5 carbon atoms, and a phenyl group,

   R ₅ to R ₁₀ are each independently one selected from the group consisting of hydrogen, an alkyl group having 1 to 5 carbon atoms, a phenyl group, and fluorine,

   o is an integer of 0 or 1,

   p is 0 or an integer from 1 to 400,

   r is an integer from 1 to 400,

   The molar ratio of p: r is 0: 100 to 80:20.
7. The method according to claim 6,

   Wherein the unit E comprises at least one compound selected from the group consisting of the following Chemical Formulas 3a to 3g:

    [Formula 3a]

   

   [Formula 3b]

   

   [Formula 3c]

   

   [Formula 3d]

   

   [Formula 3e]

   

   [Formula 3f]

   

   [Formula 3g]

   

   Where

   p is 0 or an integer from 1 to 400,

   r is an integer from 1 to 400,

   The molar ratio of p: r is 0: 100 to 80:20.
8. The method according to claim 1,

   Unit A is 1 mol or 2 mol in 1 mol of the first oligomer,

   Gel polymer electrolyte, characterized in that the molar ratio of the unit C: unit E is 1.005: 1 to 2: 1.
9. The method according to claim 1,

   The first oligomer optionally further comprises at least one or more units selected from the group consisting of a unit B represented by the following formula (4) and a unit D represented by the following formula (5).

   [Formula 4]

   * -CO-R ''-O- *

   [Formula 5]

   * -O- [R '''-O] _m- *

   Where

   R '' is a substituted or unsubstituted linear alkylene group having 1 to 10 carbon atoms, or a substituted or unsubstituted nonlinear alkylene group having 1 to 10 carbon atoms,

   R '' 'is a substituted or unsubstituted linear alkylene group having 1 to 10 carbon atoms, or a substituted or unsubstituted nonlinear alkylene group having 1 to 10 carbon atoms,

   m is an integer of 1-30.
10. The method according to claim 9,

    The unit B is a gel polymer electrolyte, characterized in that at least one compound selected from the group consisting of:

    * -CO-CH ₂ CH ₂ -O- * (Bi)

    * -CO-CHCH ₃ CH ₂ -O- * (B-ii)

    * -CO-CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ -O- * (B-iii)

    * -CO-CHCH ₃ CH ₂ CH ₂ -O- * (B-iv)
11. The method according to claim 9,

    The unit D is a gel polymer electrolyte, characterized in that at least one compound selected from the group consisting of:

    * -O-CH ₂ CH ₂ -O- * (Di)

    * -O-CHCH ₃ CH ₂ -O- * (D-ii)
12. The method according to claim 9,

    Gel polymer electrolyte, characterized in that the first oligomer is represented by at least one selected from the group consisting of the formulas 6a to 6c.

    [Formula 6a]

    [A] _s- [B] _n- [CE-] _k -C- [B] _n -A

    [Formula 6b]

    [A] _s- [CDED] _k -CA

    [Formula 6c]

    [A] _s- [B] _n- [CDED] _k -C- [B] _n -A.

    Where

    n is 0 or an integer from 1 to 30,

    k is an integer from 1 to 200,

    s is 0 or 1.
13. The method according to claim 9,

    The unit A is 1 mol or 2 mol in 1 mol of the first oligomer,

    The gel polymer characterized in that the molar ratio of the unit B: unit C: unit D: unit E is 0 to 35: 2 to 201: 0 to 35: 1 to 200 (wherein units B and D are not 0 at the same time) Electrolyte.
14. The method according to claim 9,

    The first oligomer is a gel polymer electrolyte, characterized in that at least one compound selected from the group consisting of the formula 7a to 7d.

    [Formula 7a]

    

    [Formula 7b]

    

    [Formula 7c]

    

    [Formula 7d]

    

    Where

    k is an integer from 1 to 200,

    n is an integer from 1 to 30,

    m is an integer from 1 to 30,

    p is an integer from 1 to 400,

    r is an integer from 1 to 400,

    The molar ratio of p: r is 0: 100 to 80:20.
15. The method according to claim 1,

    The gel polymer electrolyte may be methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, propyl methacrylate, butyl acrylate, butyl methacrylate, hexyl acrylate, hexyl methacrylate, Ethylhexyl acrylate, ethylhexyl methacrylate, 2,2,2-trifluoroethyl acrylate, 2,2,2-trifluoroethyl methacrylate, 2,2,3,3-tetrafluoropropyl A gel polymer electrolyte further comprising a second oligomer comprising units derived from acrylate, and at least one selected from the group consisting of 2,2,3,3-tetrafluoropropyl methacrylate.
16. The method according to claim 15,

    The second oligomer is a gel polymer electrolyte, characterized in that contained in less than 50% by weight based on the total content of the first oligomer.
17. The method according to claim 1,

    Wherein said polymer network further contains inorganic particles on said polymer network.
18. The method according to claim 1,

    Gel polymer electrolyte, characterized in that the weight average molecular weight of the first oligomer is 1,000 to 100,000.
19. The method according to claim 1,

    The gel polymer electrolyte has a Li ⁺ ion conductivity of 1.0 ~ 10 ^-4 S / cm to 2.0 ~ 10 ^-2 S / cm at 25 ℃ temperature.
20. The method according to claim 1,

    The gel polymer electrolyte is a gel polymer electrolyte, characterized in that having a Li ⁺ ion transfer coefficient of 0.3 or more at a temperature of 25 ℃.
21. The method according to claim 1,

    The gel polymer electrolyte is a gel polymer electrolyte, characterized in that the gel content of 1% by weight or more at 25 ℃ temperature.
22. The method according to claim 1,

    The gel polymer electrolyte is a gel polymer electrolyte, characterized in that the content of the unreacted oligomer relative to the total amount of the reactive oligomer at a temperature of 25 ℃ 20% or less.
23. Unit A derived from monomers comprising at least one copolymerizable acrylate or acrylic acid;

    Unit C comprising urethane; And

    A gel polymer electrolyte comprising unit E comprising siloxane.
24. Oligomers containing units comprising siloxanes,

    Li ⁺ ion conductivity of 1.0x10 ^-4 S / cm to 2.0x10 ^-2 S / cm at 25 ° C,

    Li ⁺ ion transfer coefficient of 0.3 or more, and

    Gel polymer electrolyte, characterized in that the content of the unreacted oligomer relative to the total amount of the reactive oligomer is 20% or less.
25. Lithium Salt,

    Electrolyte solvent,

    Polymerization initiator, and

    Claim 1 comprising a gel polymer electrolyte comprising a first oligomer comprising unit A derived from a monomer comprising at least one copolymerizable acrylate or acrylic acid, unit C comprising urethane, and unit E comprising siloxane. The composition for gel polymer electrolytes described in.
26. The method according to claim 25,

    The first oligomer is a gel polymer electrolyte composition, characterized in that it comprises 0.5 to 20% by weight relative to the total weight of the composition for gel polymer electrolyte.
27. The method according to claim 25,

    The first oligomer is a composition for a gel polymer electrolyte, characterized in that represented by the formula (1):

    [Formula 1]

    A- [CE] _k -CA

    Where

    k is an integer of 1 to 200.
28. The method according to claim 25,

    Unit A is a unit derived from at least one compound selected from the group consisting of hydroxymethyl (meth) acrylate and hydroxyethyl (meth) acrylate, or a unit represented by the following formula (i) Gel polymer electrolyte composition:

    

    (i).
29. The method according to claim 25,

    The unit C is a gel polymer electrolyte composition, characterized in that the unit represented by the formula (2a) or formula (2b):

    [Formula 2a]

    

    [Formula 2b]

    

    Where

    R 'is a linear or nonlinear 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, or a substituted or substituted carbon group having 6 to 20 carbon atoms or At least one selected from the group consisting of an unsubstituted arylene group, a substituted or unsubstituted biarylene group having 6 to 20 carbon atoms, a substituted or unsubstituted arylene group having 6 to 20 carbon atoms, a naphthalene group and an anthracene group.
30. The method according to claim 25,

    The unit E is a gel polymer electrolyte composition, characterized in that the unit represented by the formula (3):

    [Formula 3]

    

    Where

    R ₁ and R ₂ are linear or nonlinear alkylene groups having 1 to 5 carbon atoms,

    R ₃ and R ₄ are each independently one selected from the group consisting of hydrogen, an alkyl group having 1 to 5 carbon atoms, and a phenyl group,

    R ₅ to R ₁₀ are each independently one selected from the group consisting of hydrogen, an alkyl group having 1 to 5 carbon atoms, a phenyl group, and fluorine,

    o is an integer of 0 or 1,

    p is 0 or an integer from 1 to 400,

    r is an integer from 1 to 400,

    The molar ratio of p: r is 0: 100 to 80:20.
31. The method according to claim 25,

    Unit A is 1 mol or 2 mol in 1 mol of the first oligomer,

    A molar ratio of Unit C: E is 1.005: 1 to 2: 1.
32. The method according to claim 25,

    The first oligomer optionally further comprises at least one unit selected from the group consisting of a unit B represented by the following formula (4) and a unit D represented by the following formula (5).

    [Formula 4]

    * -CO-R ''-O- *

    [Formula 5]

    * -O- [R '''-O] _m- *

    Where

    R '' is a substituted or unsubstituted linear alkylene group having 1 to 10 carbon atoms, or a substituted or unsubstituted nonlinear alkylene group having 1 to 10 carbon atoms,

    R '' 'is a substituted or unsubstituted linear alkylene group having 1 to 10 carbon atoms, or a substituted or unsubstituted nonlinear alkylene group having 1 to 10 carbon atoms,

    m is an integer of 1-30.
33. The method according to claim 32,

    The oligomer is a gel polymer electrolyte composition, characterized in that represented by at least one selected from the group consisting of 6a to 6c.

    [Formula 6a]

    [A] _s- [B] _n- [CE-] _k -C- [B] _n -A

    [Formula 6b]

    [A] _s- [CDED] _k -CA

    [Formula 6c]

    [A] _s- [B] _n- [CDED] _k -C- [B] _n -A.

    Where

    n is 0 or an integer from 1 to 30,

    k is an integer from 1 to 200,

    s is 0 or 1.
34. The method according to claim 32,

    Unit A is 1 mol or 2 mol in 1 mol of the oligomer,

    Gel polymer electrolyte, characterized in that the molar ratio of unit B: unit C: unit D: unit E is 0 to 35: 2 to 201: 0 to 35: 1 to 200, wherein unit B and D are not 0 at the same time. .
35. The method according to claim 25,

    The first oligomer is a composition for a gel polymer electrolyte, characterized in that at least one compound selected from the group consisting of the formula 7a to 7d.

    [Formula 7a]

    

    [Formula 7b]

    

    [Formula 7c]

    

    [Formula 7d]

    

    Where

    k is an integer from 1 to 200,

    n is an integer from 1 to 30,

    m is an integer from 1 to 30,

    p is an integer from 1 to 400,

    r is an integer from 1 to 400,

    The molar ratio of p: r is 0: 100 to 80:20.
36. The method according to claim 25,

    The polymer network is a composition for a gel polymer electrolyte, characterized in that it further contains inorganic particles on the polymer network.
37. The method according to claim 25,

    The weight average molecular weight of the oligomer is a composition for a gel polymer electrolyte, characterized in that 1,000 to 100,000.
38. The method according to claim 25,

    The polymerization initiator is benzoyl peroxide, acetyl peroxide, dilauryl peroxide, di-tert-butyl peroxide, t-butyl peroxy-2-ethyl-hexanoate, cumyl hydroperoxide, hydrogen peroxide, 2 , 2'-azobis (2-cyanobutane), 2,2'-azobis (methylbutyronitrile), AIBN (2,2'-Azobis (iso-butyronitrile)) and AMVN (2,2'- Azobisdimethyl-Valeronitrile) A composition for gel polymer electrolyte, characterized in that a single substance or a mixture of two or more selected from the group consisting of.
39. The method according to claim 25,

    The polymerization initiator is a gel polymer electrolyte composition, characterized in that it comprises 0.01 to 2% by weight relative to the total content of the oligomer.
40. The method according to claim 25,

    The lithium salt may be 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 (CF ₃ SO _{2) 3, LiC 4 BO 8} , LiTFSI, LiFSI, and LiClO ₄ is any one selected from the group consisting of or a composition for the gel polymer electrolyte, it characterized in that a mixture of two or more of these.
41. The method according to claim 25,

    The lithium salt is a gel polymer electrolyte composition, characterized in that it comprises 10 to 50% by weight relative to the total content of the polymerization initiator and oligomer.
42. The method according to claim 25,

    The electrolyte solution is a gel polymer electrolyte composition, characterized in that the linear carbonate, cyclic carbonate or a combination thereof.
43. The method of claim 42,

    The linear carbonate includes any one or a mixture of two or more selected from the group consisting of dimethyl carbonate, diethyl carbonate, dipropyl carbonate, ethylmethyl carbonate, methylpropyl carbonate and ethylpropyl carbonate, wherein the cyclic carbonate is ethylene Carbonate, propylene carbonate, 1,2-butylene carbonate, 2,3-butylene carbonate, 1,2-pentylene carbonate, 2,3-pentylene carbonate, vinylene carbonate, and halides thereof A composition for gel polymer electrolyte comprising any one selected or a mixture of two or more thereof.
44. A positive electrode and a negative electrode capable of occluding and releasing lithium, and a polymer electrolyte disposed between the positive electrode and the negative electrode,

    The polymer electrolyte comprises a gel polymer electrolyte according to claim 1, characterized in that the lithium secondary battery.
45. The method of claim 44,

    Lithium secondary battery, characterized in that the charging voltage of the lithium secondary battery is 2.5V to 5.0V.
46. A first electrode, a second electrode, an electrochromic material, and

    An electrochromic device comprising the gel polymer electrolyte according to claim 1.

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