KR101396270B1 - Composite separator membrane for secondary battery and manufacturing method of the same - Google Patents

Abstract

The present invention relates to a composite separator membrane for a secondary battery which includes a porous base material layer, a hydrophilic heat resistant polymer layer, and a ceramic layer. More particularly, the present invention relates to a composite separator membrane for a secondary battery which improves heat resistance and increases the bonding force of the ceramic layer by forming a heat resistant polymer layer in a porous base material layer by using a composite separator membrane for a secondary battery which includes a hydrophilic heat resistant polymer layer which is formed in the porous base material layer, the porous base material layer, the surface of the porous base material layer and a ceramic layer which is formed in the hydrophilic heat resistant polymer layer, and a lithium secondary battery including the same.

Description

Technical Field [0001] The present invention relates to a composite separator for a secondary battery and a method for manufacturing the same,

The present invention relates to a composite separator for a secondary battery comprising a porous substrate layer, a hydrophilic heat-resistant polymer layer, and a ceramic layer, and more particularly, to a composite separator for a secondary battery comprising a porous substrate layer, a hydrophilic heat resistant polymer layer formed on the surface of the porous substrate layer, The present invention relates to a composite separator for a secondary battery and a method for manufacturing the composite separator. The composite separator for a secondary battery includes a ceramic layer formed on a surface of a porous substrate, and a hydrophilic heat-resistant polymer layer formed on the surface of the porous substrate.

Recently, interest in energy storage technology is increasing. As the application fields of cell phones, camcorders, notebook PCs and even electric vehicles are expanding, efforts for research and development of electrochemical devices are becoming more and more specified. Electrochemical devices have attracted the greatest attention in this respect, among which the development of rechargeable secondary batteries has become a focus of attention. In recent years, in order to improve the capacity density and specific energy in developing such batteries, And research and development on the design of the battery.

Among the currently applied rechargeable batteries, lithium secondary batteries developed in the early 1990s have higher operating voltages and energy densities than conventional batteries such as Ni-NH, Ni-Cd, and sulfuric acid-lead batteries using aqueous electrolyte solutions . Particularly, it is desirable that a middle- or large-sized battery module used in a hybrid vehicle or the like is manufactured with a small size and a weight as much as possible, and therefore, a design of a lithium secondary battery having a high output is desperately required.

Various studies are currently under way to enhance the safety of lithium secondary batteries. In particular, securing the heat resistance of the separator is essential for the mid- and large-sized batteries because introduction of the high heat-resistant ceramic coating layer is essential as the safety of the lithium secondary battery is directly connected. Therefore, it is required to secure the price competitiveness of the middle- to large-sized lithium secondary battery in the future, and a technology of introducing a low-cost heat-resistant coating layer is actively under way.

The polyolefin-based ceramic-coated microporous membrane of an electrochemical device is disclosed in Korean Patent Laid-Open Nos. 10-2013-0037386, 10-2010-0028009 and 10-2011-0035847 And Korean Patent Laid-Open Publication No. 10-2008-0008706 discloses a technique of coating ceramic on a separator by applying a plasma deposition method to improve heat resistance and improve adhesion between ceramic and separator. It has been reported that the membranes disclosed in the above-mentioned patents have significantly improved heat resistance as compared with uncoated membranes. However, these conventional coating methods have technical problems related to the breathability, which greatly affects the membrane performance. In such a case, when the heat-resistant coating layer is coated on the membrane by sputtering in a thin film form, a short production time and high availability for a continuous process can be expected through high output, and a binder is not needed, There is no description of a coating method in which the separator does not cause a shrinkage phenomenon when a high output is applied without affecting it.

In case of coating with a heat-resistant thin film on the membrane by sputtering, it is possible to solve the problem of increase in thickness when using a hydrophilic polymer binder in a conventional separator, deterioration of electrochemical characteristics due to pore closure, and adhesion of a ceramic layer and a separator. It is also characterized by sufficient thermal stability even at the nanometer level ceramic layer thickness.

Korean Patent Laid-Open No. 10-2011-0101768 (June 10, 2011) Korean Patent Publication No. 10-2009-0083181 (2009.09.03) Korean Patent Publication No. 10-2010-0077145 (Aug. 11, 2010) Korean Patent Publication No. 10-2008-0008706 (2008.01.28)

SUMMARY OF THE INVENTION The object of the present invention is to solve the problems described above and to provide a composite separator for a secondary battery which can improve the heat resistance by suppressing the physical deformation of the porous base layer even under high output deposition conditions by forming a hydrophilic heat resistant polymer layer on the surface of the porous base layer .

Another object of the present invention is to provide a composite separator for a secondary battery, in which the hydrophilic heat-resistant polymer layer increases the binding force between the ceramic layer and the porous base layer, thereby improving the production yield and production rate.

The present invention relates to a composite separator for a secondary battery comprising a porous base layer, a hydrophilic heat-resistant polymer layer formed on the surface of the porous base layer, and a ceramic layer formed on the surface of the hydrophilic heat-resistant polymer layer.

Reference is also made to Figures 1 and 2 as more preferred examples of the present invention.

1 is a cross-sectional view of a composite structure for a secondary battery comprising a hydrophilic heat resistant polymer layer 2 formed on one surface of a porous substrate layer 1 and a ceramic layer 3 formed on a surface of a hydrophilic heat resistant polymer layer 2, FIG.

2 is a schematic sectional view of a composite separator for a secondary battery according to another embodiment of the present invention comprising a hydrophilic heat resistant polymer layer 2 formed on both surfaces of a porous substrate layer 1 and a ceramic layer 3 formed on a surface of a hydrophilic heat resistant polymer layer 2, FIG.

 The method for producing a composite separator for a secondary battery of the present invention comprises

a) coating a hydrophilic heat-resistant polymer solution on one surface or both surfaces of the porous substrate layer and drying to prepare a hydrophilic heat-resistant polymer layer,

b) vacuum depositing a ceramic on one side or both sides of the hydrophilic heat-resistant polymer layer to produce a ceramic layer on the surface of the hydrophilic heat-resistant polymer layer,

.

The present invention provides a composite separator for a secondary battery comprising a porous base layer, a hydrophilic heat-resistant polymer layer formed on the surface of the porous base layer, and a ceramic layer formed on the surface of the hydrophilic heat-resistant polymer layer to form a hydrophilic thermostable polymer layer on the surface of the porous base layer, And to increase the bonding force with the ceramic layer.

Hereinafter, the composite separator for a secondary battery of the present invention will be described in more detail.

The present invention relates to a composite separator for a secondary battery comprising a porous substrate layer 1, a hydrophilic heat-resistant polymer layer 2 formed on the surface of the porous substrate layer 1, and a ceramic layer 3 formed on the surface of the hydrophilic heat- ,

The porous substrate layer 1 may be made of a material selected from the group consisting of polyethylene, polypropylene, polyisobutylene, polyvinyl chloride, polyvinylidene chloride, polyvinylidene fluoride, polymethyl methacrylate nylon, polyacrylonitrile, May be formed of any one, two or more of mixtures or copolymers selected from the group consisting of poly (ethylene-co-vinyl alcohol), polyethylene terephthalate, polybutylene terephthalate, polyimide, polyester, glass fiber and cellulose , The porous base material of the porous base layer has a porosity of 30 to 80% and an average pore diameter of 0.005 to 5 탆, but is not limited thereto. When the average diameter of porosity and pore is 30% or less and 0.005 탆 or less, it can act as a resistive layer. If the average porosity and pore diameter are more than 80% and 5 탆, the mechanical properties become weak and the risk of internal short circuit becomes large .

The porous substrate layer may be a porous film or a nonwoven fabric, and is preferably, but not limited to, a thickness of 5 to 100 mu m, more preferably 10 to 50 mu m because it can be used in a continuous process. When the thickness is less than 5 탆, the mechanical strength of the porous base layer becomes very weak, which may be difficult to use in a continuous process. When the thickness exceeds 100 탆, the ionic conductivity may be very low when applied to a lithium secondary battery.

The hydrophilic heat-resistant polymer layer (2) is formed by polymerization of a compound of the following formula (1). The compound of the following formula (1) has excellent heat resistance. When the polymer layer is formed on the surface of the porous base layer, And the adhesion force with the ceramic layer can be further enhanced.

[Chemical Formula 1]

[In the above formula (1)

,

,

, 티올, 니트릴, 알데하이드, 이미다졸, 아자이드, 할로겐 또는 하이드록시이며, 서로 동일하거나 상이할 수 있고, 동시에 수소인 경우는 제외한다.R ₁ to R ₅ represent hydrogen,

,

,

, Thiol, nitrile, aldehyde, imidazole, azide, halogen or hydroxy, which may be the same or different and are simultaneously hydrogen.

Wherein R ₁₁ to R ₁₅ are hydrogen or (C ₁ -C ₅ ) alkyl and may be the same or different from each other.

로부터 선택될 수 있다.More specifically, at least one of R ₁ to R ₅ is

Lt; / RTI >

The thickness of the hydrophilic heat-resistant polymer layer is not limited thereto, but is preferably 5 to 500 nm, more preferably 15 to 200 nm. If it is 5 nm or less, it may be difficult to secure sufficient heat resistance, and if it is more than 500 nm, the battery performance may be deteriorated.

Since the ceramic layer 3 exhibits strong mechanical properties and excellent heat resistance at high temperatures, it improves the thermal stability of the porous substrate layer even under high temperature or overcharging conditions in a lithium secondary battery, thereby solving the safety problem due to internal short circuit between the positive electrode and the negative electrode The giver plays a role. Concrete, for example TiO _2, SiO _2, SnO _2, CeO _2, ZrO _2, CaCO _3, BaTiO _3, Al ₂ O _3, Al (OH) ₃ and Mg (OH) may be made of _two, such as, limited to It is not.

The thickness of the ceramic layer is not limited thereto, but is preferably 50 to 2,000 nm, more preferably 100 to 1000 nm. When the thickness is less than 50 nm, the heat resistance characteristics of the composite separator may not be changed because the ceramic is not sufficiently coated. If the thickness is 2,000 nm or more, the porosity of the porous substrate may be blocked by the ceramic layer.

The method of forming a ceramic layer in the present invention is a method of forming a ceramic layer by generating plasma at a relatively low vacuum (7 × 10 ^-3 Torr) as a kind of vacuum deposition method, accelerating ionized argon gas to impinge on a target, It is a principle. The sputtering condition is 25 W / ㎠ at room temperature, and the collided ceramic is coated on the separator by atomic unit.

Hereinafter, the method for producing the composite separator for a secondary battery of the present invention will be described in more detail.

The method for producing a composite separator for a secondary battery of the present invention comprises

a) coating a hydrophilic heat-resistant polymer solution on one surface or both surfaces of the porous substrate layer and drying to prepare a hydrophilic heat-resistant polymer layer,

b) vacuum depositing a ceramic on one side or both sides of the hydrophilic heat-resistant polymer layer to produce a ceramic layer on the surface of the hydrophilic heat-resistant polymer layer,

.

The hydrophilic heat-resistant polymer solution of step (a) is prepared by dissolving the compound of formula (1) in a solution of pH 7 to 11,

[Chemical Formula 1]

[In the above formula (1)

,

,

, 티올, 니트릴, 알데하이드, 이미다졸, 아자이드, 할로겐 또는 하이드록시이며 서로 동일하거나 상이할 수 있고, 동시에 수소인 경우는 제외한다.R ₁ to R ₅ represent hydrogen,

,

,

, Thiol, nitrile, aldehyde, imidazole, azide, halogen or hydroxy and may be the same or different and are not simultaneously hydrogen.

Wherein R ₁₁ to R ₁₅ are hydrogen or (C ₁ -C ₅ ) alkyl and may be the same or different from each other.

The compound of Chemical Formula 1 can be used as dopamine and norepinephrine which can improve the heat resistance and binding ability with the ceramic layer and hardly affect the air permeability. The compound of formula (1) including the dopamine and norepinephrine can be self-polymerized at a constant pH range including an alkyl alcohol, has excellent chemical stability, can be coated at 50 nm or less, This is good. Especially, when dopamine is used instead of organic solvent which is expensive and harmful to human body, it is advantageous to use environmentally friendly and cheap distilled water based buffer solution.

The dopamine and norepinephrine contained in the compound of Formula 1 are preferably spontaneously polymerized in a buffer solution of pH 7 to 11, more preferably of pH 8 to 10 as shown in Reaction Formula 1 for dopamine and Reaction Formula 2 for norepinephrine .

[Reaction Scheme 1]

[Reaction Scheme 2]

In addition, the buffer solution is not limited to the kind, and one or more alcohols such as methanol and ethanol as well as distilled water may be added.

The compound of Formula 1 may be included in the buffer solution to form a coating solution. When the porous substrate is impregnated with the coating solution and then taken out and washed for a predetermined time, the compound of Formula 1 may be polymerized on the surface of the porous substrate layer to form a hydrophilic heat resistant polymer layer.

The impregnation may be performed by a variety of methods such as a pressure coating method, a spin coating method, a spraying method or a roller coating method, but not limited thereto.

The method may further include the step of plasma at the surface of the hydrophilic heat-resistant polymer layer in the step a), and the plasma is generated in a conventional manner by discharging a high-frequency AC voltage in the gas, that is, the working gas. The working gas for the plasma treatment may preferably be nitrogen, oxygen, air, argon, helium, carbon dioxide, carbon monoxide and ozone, and more preferably nitrogen, oxygen, air, argon, Or a mixture of two or more. Argon was used as the working gas for the plasma treatment of the present invention, but the present invention is not limited thereto. The plasma treatment should preferably be performed at a temperature in the range of 25 to 30 DEG C and 25 to 70 W / cm < 2 >. These conditions are preferable because they can inhibit the physical deformation of the separator.

The present invention provides a composite separator for a secondary battery comprising a porous base layer, a hydrophilic heat-resistant polymer layer formed on the surface of the porous base layer, and a ceramic layer formed on the surface of the hydrophilic heat-resistant polymer layer to form a hydrophilic thermostable polymer layer on the surface of the porous base layer, The physical deformation of the porous base layer is suppressed when the ceramic layer is coated, and the adhesive force is excellent, so that the binding force with the ceramic layer can be increased. Further, by forming a ceramic layer on the surface of the hydrophilic heat-resistant polymer layer, the thermal stability of the porous resin layer is improved even under high temperature or overcharge conditions in the lithium secondary battery, thereby solving the safety problem due to internal short circuit between the anode and the cathode.

In the production of the composite separator for a secondary battery according to the present invention, it is possible to improve the heat resistance of the composite separator to suppress physical deformation under high output deposition conditions, and to improve the production yield and production rate.

FIG. 1 illustrates the structure of a composite separator coated on one side in the present invention.
2 shows the structure of a composite separator coated on both sides in the present invention.
3 compares the thermal stability of the composite membranes according to Examples 1 to 3 and Comparative Examples 1 to 3 of the present invention.
Fig. 4 is a comparison of the ceramics attached to the tape after the adhesive strength evaluation of the composite separator according to Example 2 and Comparative Example 1 of the present invention.

Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to the following examples.

The following physical properties were measured by the following methods.

1) Measurement of Thickness of Ceramic Coated Composite Membrane

The thickness of the ceramics coating layer coated on the surface of the porous substrate layer was measured by depth profiling using x-ray photoelectron spectroscopy (XPS).

2) Measurement of thickness of hydrophilic heat-resistant polymer layer

The thickness of the heat-resistant polymer layer coated on the surface of the porous substrate layer was measured by depth profiling using x-ray photoelectron spectroscopy.

3) Air permeability (sec / 100 ml)

A sample having a size of 60 × 60 mm was collected from the porous base layer and the time required for passing 100 ml of air through a densometer (N4110, Thwing-Albert, USA) was measured.

4) Heat shrinkage (%)

A sample having a size of 30 mm × 30 mm was prepared using the composite membrane thus prepared, and allowed to stand at 140 ° C. for 30 minutes, and the shrinkage ratio was measured.

5) Evaluation of film adhesion force

The specimens prepared in the following Examples and Comparative Examples were cut to a size of 15 mm × 15 mm and tape was attached. Then, a high-precision micromechanical test system (Delaminator Adhesion Test System: DTS Company, Menlo Park, CA, USA) at 180 占 폚 and peel-off at a rate of 100 占 퐉 / s to measure the binding force.

[Example 1]

(10 mmol tris buffer solution, pH 8.5) in distilled water-based buffer solution: methanol was mixed at a ratio of 1: 1, 2 mg of dopamine was dissolved per 1 ml of the buffer solution and the methanol mixture solution, and the mixture was stirred for 30 seconds to prepare a coating solution. (Polyethylene, Polyethylene, ND420, Asahi Kasei E-materials, Japan) was impregnated into the solution and stirred at 500 rpm for 1 hour to induce a spontaneous polymerization reaction. Thus, a hydrophilic The heat-resistant polymer solution was coated to form a 45 nm-thick hydrophilic heat-resistant polymer layer on the surface of the porous base layer. After coating, the coating was washed with acetone, distilled water and acetone in the order of filtration and dried in an oven at 60 ° C for 12 hours. The physical properties of the coating were measured to be 260 sec / 100 ml, The hydrophilic heat-resistant polymer layer was formed, and an argon gas was injected into the sputter chamber. At this time, the chamber was maintained at a temperature of 25 to 30 DEG C, and the pressure in the chamber was adjusted to 2 x 10 < ^-5 > Torr. The plasma was generated at a low vacuum of 2 × 10 ^-5 Torr to accelerate the ionized argon gas. The pressure of the chamber was 7 × 10 ^-3 Torr, pre-sputtered at 25 W / cm 2 output, accelerated ionized argon gas Al ₂ O ₃ was coated for 10 minutes to form a ceramic layer of 121 nm. Physical properties of the ceramic layer were measured and the results are shown in Table 2.

[Example 2]

Example 1 was prepared in the same manner as in Example 1 except that the precursor was sputtered at an output of 50 W / cm 2 and the ionized argon gas was accelerated and Al ₂ O ₃ was coated for 10 minutes to form a ceramic layer of 253 nm. Table 2 shows the results of measuring the physical properties by the above method.

[Example 3]

Example 1 was prepared in the same manner as in Example 1, except that the precursor was sputtered at an output of 70 W / cm 2 and the ionized argon gas was accelerated and Al ₂ O ₃ was coated for 10 minutes to form a 379 nm ceramic layer. Table 2 shows the results of measuring the physical properties by the above method.

[Example 4]

(10 mmol tris buffer solution, pH 8.5) mixed with methanol at a ratio of 1: 1, 2 mg of norepinephrine was dissolved in 1 ml of the buffer solution and methanol solution, and the mixture was stirred for 30 seconds to prepare a coating solution . (Polyethylene, Polyethylene, ND420, Asahi Kasei E-materials, Japan) was impregnated into the solution and stirred at 500 rpm for 1 hour to induce a spontaneous polymerization reaction. Thus, a hydrophilic The heat-resistant polymer solution was coated to form a 45 nm-thick hydrophilic heat-resistant polymer layer on the surface of the porous base layer. After the coating, the substrate was washed with acetone, distilled water and acetone through a filter process, dried in an oven at 60 ° C for 12 hours, and a hydrophilic heat-resistant polymer layer was formed on the surface of the porous substrate. Then, argon gas was injected into the sputter chamber. At this time, the chamber was maintained at a temperature of 25 to 30 DEG C, and the pressure in the chamber was adjusted to 2 x 10 < ^-5 > Torr. The plasma was generated at a low vacuum of 2 × 10 ^-5 Torr to accelerate the ionized argon gas. The pressure of the chamber was 7 × 10 ^-3 Torr, pre-sputtered at 25 W / cm 2 output, accelerated ionized argon gas And Al ₂ O ₃ was coated for 10 minutes to form a 122 nm-thick ceramic layer. Physical properties of the resulting ceramic layer were measured.

[Comparative Example 1]

A porous substrate (polyethylene, Polyethylene, ND420, Asahi Kasei E-materials, Japan) having a thickness of 20 탆 was placed in a sputter chamber, and then argon gas was injected into the sputter chamber. At this time, the chamber was maintained at a temperature of 25 to 30 DEG C, and the pressure in the chamber was adjusted to 2 x 10 < ^-5 > Torr. The plasma was generated at a low vacuum of 2 × 10 ^-5 Torr to accelerate the ionized argon gas. The pressure of the chamber was 7 × 10 ^-3 Torr, pre-sputtered at 25 W / cm 2 output, accelerated ionized argon gas And Al ₂ O ₃ was coated for 10 minutes to form a 119 nm ceramic layer. Physical properties of the thus-obtained ceramic layer were measured and the results are shown in Table 2.

[Comparative Example 2]

The same procedure as in Comparative Example 1 was carried out except that the comparative example 1 was subjected to free sputtering at an output of 50 W / cm 2 and an ionized argon gas was accelerated and Al ₂ O ₃ was coated for 10 minutes to form a ceramic layer of 254 nm. Table 2 shows the results of measuring the physical properties by the above method.

[Comparative Example 3]

The same procedure as in Comparative Example 1 was carried out except that Al ₂ O ₃ was coated for 10 minutes by accelerating the ionized argon gas at the output of 70 W / cm ₂ in Comparative Example 1 to form a 383 nm ceramic layer. Table 2 shows the results of measuring the physical properties by the above method.

[Table 1]

[Table 2]

In Examples 1 to 4, in which the hydrophilic thermostable polymer layer and the ceramic layer were formed in Table 2, and in Comparative Examples 1 to 3, in which the hydrophilic thermostable polymer layer was not formed, it was confirmed that there was almost no difference in air permeability. Layer of polydopamine, polyneophenephrine and ceramic layers were found to have little effect on air permeability.

1 shows a composite separator for a secondary battery in which a hydrophilic heat-resistant polymer layer is formed on one surface of a porous substrate layer and a ceramic layer is formed on the surface of the hydrophilic heat-resistant polymer layer. FIG. 2 is a cross- And a ceramic layer is formed on the surface of the hydrophilic heat-resistant polymer layer to form a composite separator for a secondary battery.

3 is a cross-sectional view of a porous separator according to another embodiment of the present invention. The porous separator includes a porous substrate layer, Sputtering, and FIG. 3 is a comparison of the heat resistance of each.

When the ceramic layer was formed by sputtering at 25 ° C and 25 W / cm 2 for 10 minutes, the composite membrane and the membrane without the hydrophilic heat resistant polymer layer did not show any difference in heat resistance.

When the ceramic layer was formed by sputtering at 25 ° C and 50 W / cm 2 for 10 minutes, the shrinkage phenomenon did not occur in the case of the composite separator but the shrinkage phenomenon occurred in the separator in which the hydrophilic heat resistant polymer layer was not formed.

When the ceramic layer was formed by sputtering at 25 ° C and 70 W / cm 2 for 10 minutes, the shrinkage phenomenon did not occur in the case of the composite separator but the shrinkage phenomenon occurred in the case of the separator in which the hydrophilic heat resistant polymer layer was not formed.

As a result, it was confirmed that when the hydrophilic heat resistant polymer layer was formed on the composite separator, the heat resistance was improved and the shrinkage phenomenon was reduced when the sputter was used at a high output.

4 is a graph comparing the adhesive strengths of the composite separator according to Example 2 and Comparative Example 1. The comparative separator was prepared by forming a hydrophilic heat-resistant polymer layer on the surface of the porous base layer and forming a ceramic layer on the surface of the hydrophilic heat- An adhesive strength test was carried out with a Scotch tape through a separating film having a ceramic layer formed on the surface of the substrate layer.

On the left side of FIG. 4, it was confirmed that the ceramic layer did not fall off the Scotch tape as a result of the adhesion test according to Example 2, and on the right side, it was confirmed that the ceramic layer fell off the Scotch tape as a result of the adhesion test according to Comparative Example 1 .

When the hydrophilic heat resistant polymer layer was formed on the surface of the porous base layer from the above results, it was confirmed that the hydrophobic porous base layer became hydrophilic due to the hydrophilic heat resistant polymer layer and exhibited strong adhesion to the ceramic layer.

1: Porous substrate layer
2: Hydrophilic heat-resistant polymer layer
3: Ceramic layer

Claims (12)

A porous substrate layer, a hydrophilic heat-resistant polymer layer formed by polymerizing a compound of Formula 1 on one or both surfaces of the porous substrate layer, and a ceramic layer formed on a surface of the hydrophilic heat-resistant polymer layer.
[Chemical Formula 1]

[In the above formula (1)
R ₁ to R ₅ represent hydrogen,

,

,

, Thiol, nitrile, aldehyde, imidazole, azide, halogen or hydroxy, which may be the same or different and are simultaneously hydrogen.
Wherein R ₁₁ to R ₁₅ are hydrogen or (C ₁ -C ₅ ) alkyl and may be the same or different from each other. The method according to claim 1,
Wherein the porous substrate layer is selected from the group consisting of polyethylene, polypropylene, polyisobutylene, polyvinyl chloride, polyvinylidene chloride, polyvinylidene fluoride, polymethyl methacrylate nylon, polyacrylonitrile, polyvinyl alcohol, poly a mixture or copolymer selected from the group consisting of polyethylene terephthalate, polybutylene terephthalate, polyimide, polyester, glass fiber, and cellulose. The method according to claim 1,
Wherein at least one of R ₁ to R ₅ is

Composite Membrane for Secondary Battery. The method according to claim 1,
Wherein the hydrophilic heat-resistant polymer layer is formed by polymerization of dopamine or norepinephrine. The method according to claim 1,
The ceramic layer is _{TiO 2, SiO 2, SnO 2} , CeO 2, ZrO 2, CaCO 3, BaTiO 3, Al 2 O 3, Al (OH) 3 and Mg (OH) ₂ more than one or two selected from the Wherein the composite separator is a composite separator for a secondary battery. The method according to claim 1,
Wherein the thickness of the porous base layer is 5 to 100 占 퐉, the thickness of the hydrophilic heat-resistant polymer layer is 5 to 500 nm, and the thickness of the ceramic layer is 10 to 2,000 nm. A lithium secondary battery comprising a composite separator for a secondary battery according to any one of claims 1 to 6. a) coating a hydrophilic heat-resistant polymer solution obtained by dissolving a compound of the following formula (1) in a solution having a pH of 7 to 11 on one side or both sides of the porous substrate layer and drying the resultant to prepare a hydrophilic heat-
b) vacuum depositing a ceramic on the surface of the hydrophilic heat-resistant polymer layer to produce a ceramic layer on the surface of the hydrophilic heat-resistant polymer layer,
Wherein the composite separator has a thickness of 10 to 100 nm.
[Chemical Formula 1]

[In the above formula (1)
R ₁ to R ₅ represent hydrogen,

,

,

, Thiol, nitrile, aldehyde, imidazole, azide, halogen or hydroxy and may be the same or different and are not simultaneously hydrogen.
Wherein R ₁₁ to R ₁₅ are hydrogen or (C ₁ -C ₅ ) alkyl and may be the same or different from each other. 9. The method of claim 8,
Wherein at least one of R ₁ to R ₅ is

Wherein the composite separator has a surface area of at least 10 탆. 9. The method of claim 8,
Wherein the hydrophilic heat-resistant polymer solution is a solution of dopamine or norepinephrine dissolved therein. 9. The method of claim 8,
Wherein the coating method of the step a) is coated by a method selected from an immersion coating method, a pressure coating method, a spin coating method, a spraying method or a roller coating method. 9. The method of claim 8,
Further comprising the step of plasma on the surface of the hydrophilic heat-resistant polymer layer in the step a).

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