KR101859251B1 - Electrode composite, electrochemical device comprising the same and preparation method of the electrode composite - Google Patents

Abstract

The present invention relates to an electrode composite, an electrochemical device including the same, and a method of manufacturing the electrode composite. An electrode composite of the present invention comprises: an electrode having an electrode active material layer formed on at least one surface of an electrode current collector; And a porous binder layer comprising a polyvinylidene fluoride (PVdF) binder, an acrylic binder, or a mixture thereof, coated on the electrode active material layer, wherein the thickness of the porous binder layer is 0.5 to 5 탆. According to the method of the present invention, it is possible to manufacture an electrode composite and an electrochemical device including the electrode composite, which are excellent in adhesion between the electrode and the separator, structurally stable, and excellent in air permeability between the electrode and the separator.

Description

TECHNICAL FIELD [0001] The present invention relates to an electrode composite, an electrochemical device including the electrode composite, and a method of manufacturing the electrode composite.

The present invention relates to an electrode composite, an electrochemical device including the same, and a method of manufacturing the electrode composite.

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. The electrochemical device is one of the most attracting fields in this respect, and development of a rechargeable secondary battery is of particular interest.

Among the currently applied secondary batteries, the lithium secondary batteries developed in the early 1990's are attracting attention because they have higher operating voltage and higher energy density than conventional batteries such as Ni-MH.

However, in a lithium secondary battery, there is a fear that an exothermic phenomenon occurs depending on the use environment such as the structure between the separator and the electrode, and the explosion may occur.

In addition, the lithium secondary battery has a binder layer formed on the surface thereof in contact with electrodes included therein by a method such as phase separation. However, in the secondary battery having such a binder layer, difficulty in improving performance such as thinning and air permeability And the manufacturing method thereof is also complicated.

In order to improve the safety of the secondary battery, in order to improve the safety of the secondary battery, it is necessary to increase the coupling strength between the electrode and the separator, There is still a need for a thin and porous binder layer between the electrode and the separator and an electrode or electrode composite using the same that can suppress the resistance at the interface between the separator and the electrode due to the generated electrode side reaction and improve the air permeability .

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide an electrode composite that can exhibit excellent adhesion with a separation membrane without interfering with the output of the secondary battery.

Also, a method for producing the electrode composite and an electrochemical device including the electrode composite are provided.

According to one aspect of the present invention, there is provided an electrode composite comprising: an electrode having an electrode active material layer formed on at least one surface of an electrode current collector; And a porous binder layer comprising a polyvinylidene fluoride (PVdF) binder, an acrylic binder, or a mixture thereof, coated on the electrode active material layer, wherein the thickness of the porous binder layer is 0.5 to 5 탆.

According to another aspect of the present invention, there is provided a method of manufacturing an electrode composite, comprising: providing an electrode active material layer coated on at least one surface of an electrode current collector; Coating a binder emulsion comprising a polyvinylidene fluoride (PVdF) binder, an acrylic binder or a mixture thereof, and a dispersion medium on the active material layer; And removing the dispersion medium from the coated binder emulsion to form a porous binder layer, wherein the melting temperature (Tm) of the binder emulsion is higher than the temperature at which the dispersion medium is removed from the binder emulsion.

According to an embodiment of the present invention, the electrode composite to which the porous binder layer is applied can exhibit excellent adhesion with the separation membrane and is structurally stable, and the binder layer formed on the active material layer is porous. For this reason, the electrochemical device according to one aspect of the present invention can exhibit excellent output.

According to another aspect of the present invention, there is provided a method of manufacturing the above-described electrode composite.

Hereinafter, the present invention will be described in detail. Prior to this, terms and words used in the present specification and claims should not be construed as limited to ordinary or dictionary terms, and the inventor may designate the concept of a term appropriately in order to describe its own invention in the best way possible. It should be interpreted as meaning and concept consistent with the technical idea of the present invention. Therefore, the constitutions described in the embodiments described herein are merely the most preferred embodiments of the present invention, and are not intended to represent all of the technical ideas of the present invention. Therefore, various equivalents which can be substituted at the time of application It should be understood that variations can be made.

The term 'electrode composite' as used herein refers to a structure in which a porous binder coating layer is formed on the electrode active material layer in an electrode in which an electrode active material layer is coated on the electrode current collector.

According to an aspect of the present invention, there is provided an electrode composite comprising: an electrode current collector formed on at least one surface thereof with an electrode active material coated thereon; And a porous binder layer comprising a polyvinylidene fluoride (PVdF) binder, an acrylic binder or a mixture thereof, coated on the electrode active material layer, wherein the porous binder layer has a thickness of 0.5 to 5 μm .

In one aspect of the invention, the binder emulsion comprises a polyvinylidene fluoride (PVdF) binder, an acrylic binder or mixtures thereof, and a dispersion medium.

The binder emulsion constituting the binder layer of the electrode contains a polyvinylidene fluoride (PVdF) binder, an acrylic binder, or a mixture thereof, so that the dispersibility of the binder during the formation of the binder emulsion, Permeability and structural stability of the binder layer and adhesion of the binder layer to the separator can be improved in balance so that the stability and performance of the electrochemical device using such an electrode composite including the electrode and the binder layer Can greatly contribute.

The binder emulsion has a form in which spherical particles having a diameter in the range of several hundreds nm are dispersed evenly in the dispersion medium. If necessary, the binder emulsion may contain a surfactant. The binder layer formed from such a binder emulsion has a cross-packed structure in which spherical particles of several hundreds of nanometers in diameter are stacked, and can have a porosity of 10 to 80%, a porosity of 20 to 70%, or a porosity of 30 to 60% .

The binder of the polyvinylidene fluoride (PVdF) system is uniformly dispersed without being dissolved by the dispersion medium in the step of forming the binder layer. After removal of the dispersion medium, the binder layer is excellent in adhesion to the separation membrane, And a structurally stable and excellent performance binder layer having a thickness thinner than that of the conventional binder layer on the electrode can be formed.

Examples of such polyvinylidene fluoride (PVdF) binder include polyvinylidene fluoride-co-hexafluoropropylene, polyvinylidene fluoride-co-trichlorethylene, polyvinylidene fluoride-co- There may be mentioned fluoroethylene, polyvinylidene fluoride-co-trifluoroethylene, polyvinylidene fluoride-co-trifluorofluoroethylene and polyvinylidene fluoride-co-ethylene.

The polyvinylidene fluoride (PVdF) based binder may be used alone or in combination with an acrylic binder as a binder emulsion and ultimately as a binder layer. In such a combination, the more advantageous properties of the acrylic binder may be utilized depending on the combination ratio.

The acrylic binder may be a copolymer including at least one first functional group selected from the group consisting of an OH group and a COOH group, and at least one second functional group selected from the group consisting of an amine group and an amide group.

In another embodiment, the acrylic binder may have a repeating unit derived from a monomer having a first functional group and a repeating unit derived from a monomer having a second functional group.

In another embodiment, the monomer having the first functional group is selected from the group consisting of (meth) acrylic acid, 2- (meth) acryloyloxyacetic acid, 3- (meth) acryloyloxypropyl acid, 4- (Meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, (Meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyleneglycol (meth) acrylate, 6-hydroxyhexyl One or more,

The monomer having the second functional group may be selected from the group consisting of 2 - ((butoxyamino) carbonyloxy) ethyl (meth) acrylate, 2- (diethylamino) ethyl (Meth) acrylate, methyl 2-acetamido (meth) acrylate, 3- (dimethylamino) propyl (meth) acrylate, Acrylamidoglycolic acid, 2- (meth) acrylamido-2-methyl-1-propanesulfonic acid, (3- (meth) acrylamidopropyl) trimethylammonium chloride, N- (Meth) acrylamide, N-tert-butyl (meth) acrylamide, diacetone (meth) acrylamide, (Meth) acrylamide, N, N-dimethyl (meth) acrylamide, N- (isobutoxymethyl) acrylamide, N- (Meth) acrylamide, N, N '- (1,3-phenylene) dimaleimide, N-N'- (Meth) acrylamide and N-vinylpyrrolidinone (N, N'-dicyclohexyl) dimaleimide, N, N'- And the like.

In another embodiment, the acrylic binder is selected from the group consisting of ethyl acrylate-acrylic acid-N, N-dimethyl acrylamide copolymer and ethyl acrylate-acrylic acid 2- (dimethylamino) ethyl acrylate copolymer. Or more.

Such an acryl-based binder improves the adhesive strength between the electrode composite and the separator to be formed later and the performance such as air permeability between the electrode composite and the separator, which are formed later, according to the improved dispersibility in the dispersion medium during the binder emulsion forming process. Accordingly, such an acrylic binder can form a uniform binder layer on the electrode in addition to the above-mentioned PVdF binder, thereby preventing the binder layer from being eliminated, and providing electrochemical performance and stability.

The thickness of the porous binder layer is 0.5 to 5 占 퐉. When the thickness of the porous binder layer is less than 0.5 탆, it is advantageous in improving the performance such as air permeability between the electrode composite and the separation membrane, but the adhesion force is greatly deteriorated and can be easily separated from each other. On the other hand, when the thickness of the porous binder layer is more than 5 탆, it is advantageous to improve the adhesion between the electrode composite and the separator, but it may be greatly disadvantageous in performance such as air permeability.

The region where the porous binder layer is in contact with the active material layer is 40 to 100% of the total area of the active material layer. In the case where the porous binder layer is formed below the lower limit value, it may be difficult to maintain the bonding after bonding. On the other hand, an aspect in which the porous binder layer covers the entire active material layer also corresponds to the present invention. Since a step is formed between the active material layer and the non-coated portion of the electrode current collector, the porous binder layer coated for adhesion with the separator may be formed only on the active material layer.

The porous binder layer may be coated on the active material layer in a predetermined pattern. Specifically, the porous binder layer contacting the active material layer may have a predetermined non-coated area. The uncoated portion of the porous binder layer should be present within a range that does not adversely affect the adhesion between the electrode composite and the separator. It is clear that such a non-porous portion will not adversely affect the performance such as air permeability between the electrode composite and the separator.

In the manufacturing method according to one aspect of the present invention, the electrode active material (i.e., the positive electrode active material and the negative electrode active material) and the electrode current collector (i.e., the positive electrode collector and the negative electrode collector) of the present invention are not particularly limited, Can be prepared according to known conventional methods or modified methods thereof.

The cathode active material may be a layered compound such as lithium cobalt oxide (LiCoO ₂ ), lithium nickel oxide (LiNiO ₂ ), or a compound substituted with at least one transition metal; A lithium manganese oxide (LiMnO ₂ ) such as LiMnO ₃ , LiMn ₂ O ₃ , LiMnO _2, etc. represented by the formula Li _{1 + x} Mn _{2 -x} O ₄ (where x is 0 to 0.33); Lithium copper oxide (Li ₂ CuO ₂ ); Vanadium oxides such as LiV ₃ O ₈ , LiFe ₃ O ₄ , V ₂ O ₅ and Cu ₂ V ₂ O ₇ ; A nickel-situ type lithium nickel oxide represented by the formula LiNi _1-x M _x O ₂ (where M = Co, Mn, Al, Cu, Fe, Mg, B or Ga and x = 0.01 to 0.3) oxide); Formula _{LiMn 2-x M x O 2} ( where, M = Co, Ni, Fe , Cr, and Zn, or Ta, x = 0.01 to 0.1 Im) or Li ₂ Mn ₃ MO ₈ (where, M = Fe, Co, Ni, Cu, or Zn); LiMn ₂ O _{4 in} which part of the lithium in the formula is substituted with an alkaline earth metal ion; Disulfide compounds; Fe ₂ (MoO ₄ ) _3, or a composite oxide formed of a combination of these materials, and the like, and are not limited thereto.

The cathode current collector has a thickness of 3 to 500 mu m, for example. Such a positive electrode current collector is not particularly limited as long as it has conductivity without causing chemical change in the battery. For example, the positive electrode current collector may be formed of a material such as carbon, stainless steel, aluminum, nickel, titanium, sintered carbon, , Nickel, titanium, silver, or the like may be used. The electrode current collector may have fine irregularities on its surface to increase the adhesive force of the cathode active material, and various forms such as a film, a sheet, a foil, a net, a porous body, a foam, and a nonwoven fabric are possible.

A conductive material may be further mixed with the positive electrode active material particles. Such a conductive material is added, for example, in an amount of 1 to 50% by weight based on the total weight of the mixture including the cathode active material. Such a conductive material is not particularly limited as long as it has high conductivity without causing chemical changes in the battery, and examples thereof include graphite such as natural graphite and artificial graphite; Carbon black such as carbon black, acetylene black, ketjen black, channel black, furnace black, lamp black, and summer black; Conductive fibers such as carbon fiber and metal fiber; Metal powders such as carbon fluoride, aluminum, and nickel powder; Conductive whiskey such as zinc oxide and potassium titanate; Conductive oxides such as titanium oxide; Conductive materials such as polyphenylene derivatives and the like can be used.

The binder is added to the binder in an amount of 1 to 50% by weight, based on the total weight of the mixture including the cathode active material, for example, as a component for bonding the cathode active material particles to the conductive material or the like and for bonding to the electrode current collector. Examples of such binders include polyvinylidene fluoride, polyvinyl alcohol, carboxymethylcellulose (CMC), starch, hydroxypropylcellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene , Polypropylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, styrene butylene rubber, fluorine rubber, various copolymers and the like.

Non-limiting examples of the solvent include acetone, tetrahydrofuran, methylene chloride, chloroform, dimethylformamide, N-methyl-2-pyrrolidone (N -methyl-2-pyrrolidone, NMP), cyclohexane, water, or a mixture thereof. These solvents provide an appropriate level of viscosity so that a slurry coating layer can be formed at a desired level on the electrode collector surface.

The negative electrode is manufactured by coating and drying the negative electrode active material particles on the negative electrode collector, and may further include components such as the above-described conductive material, binder, solvent and the like, if necessary.

The negative electrode collector has a thickness of 3 to 500 mu m, for example. Such an anode current collector is not particularly limited as long as it has conductivity without causing chemical change in the battery, and may be formed of a material such as copper, stainless steel, aluminum, nickel, titanium, fired carbon, surface of copper or stainless steel A surface treated with carbon, nickel, titanium, silver or the like, an aluminum-cadmium alloy, or the like can be used. In addition, like the positive electrode collector, fine unevenness can be formed on the surface to enhance the bonding force of the negative electrode active material, and it can be used in various forms such as films, sheets, foils, nets, porous bodies, foams and nonwoven fabrics.

Examples of the negative electrode active material include carbon such as non-graphitized carbon and graphite carbon; _{Li x Fe 2 O 3 (0≤x≤1} ), Li x WO 2 (0≤x≤1), Sn x Me 1-x Me 'y O z (Me: Mn, Fe, Pb, Ge; Me' : Metal complex oxides of Al, B, P, Si, Group 1, Group 2, Group 3 elements of the periodic table, halogen, 0 < x &lt; Lithium metal; Lithium alloy; Silicon-based alloys; Tin alloy; _{SnO, SnO 2, PbO, PbO} 2, Pb 2 O 3, Pb 3 O 4, Sb 2 O 3, Sb 2 O 4, Sb 2 O 5, GeO, GeO 2, Bi 2 O 3, Bi 2 O 4, Bi ₂ O ₅ and the like; Conductive polymers such as polyacetylene; Li-Co-Ni-based materials and the like can be used.

According to one aspect of the present invention, an electrode composite can be produced as follows.

First, an electrode having an electrode active material layer coated on at least one surface of a current collector is provided (step S1).

The process of providing such an electrode is as follows.

The electrode active material, the electrode current collector, the binder, and the like are as described above with respect to the electrode composite structure.

A binder suitable for an electrode active material such as a desired anode or cathode is added to and dissolved in a solvent to form a binder solution and then the desired electrode active material particles are added to the resulting binder solution and this mixture is further mixed with stirring The electrode active material particles are uniformly dispersed in the binder solution to prepare a slurry, and the slurry thus prepared is sequentially coated on at least one surface of the electrode current collector in the form of a layer.

Application of the active material slurry can be carried out continuously or discontinuously by various methods such as slot die coating, slide coating, curtain coating, and the like. Particularly, from the viewpoint of productivity, it is preferable that the application is performed continuously or simultaneously at the same time with respect to various electrode current collectors.

The solvent is removed from the active material slurry applied on the electrode current collector. The solvent may be removed, for example, by drying. The active material slurry applied onto the electrode current collector is simultaneously or separately dried by using a drier or the like to remove the solvent to obtain an electrode or an electrode assembly.

As a method of coating the active material slurry on the electrode current collector, a conventional coating method known in the art may be used. For example, a dip coating, a die coating, a roll coating, a comma, A coating method or a mixing method thereof may be used.

When a solvent is added to the coating liquid, a drying process of the coating layer is further required. Drying conditions are possible in a batch or continuous manner using an oven or a heated chamber in a temperature range that takes into account the vapor pressure of the solvent used.

Next, the binder emulsion is coated on the active material layer of the electrode manufactured in the step S1 (step S2).

The binder component used in the binder emulsion refers to the above in relation to the electrode composite.

The dispersion medium used in the binder emulsion is a component constituting the binder emulsion together with the binder component to form a binder emulsion capable of achieving optimal porosity after drying the binder emulsion. The binder used in the binder and the solubility index And a dispersion medium having a low boiling point is preferable. The dispersion medium can be mixed with a uniform binder, that is, the binder can be uniformly dispersed in the dispersion medium. Thereafter, the dispersion medium is removed, and thus, a large number of pores can be formed. .

Non-limiting examples of the dispersion medium include acetone, tetrahydrofuran, methylene chloride, chloroform, dimethylformamide, N-methyl-2-pyrrolidone (NMP), cyclohexane, water or mixtures thereof. When water is used as a dispersion medium to form an aqueous emulsion, it can be a more environmentally friendly process.

In another embodiment, the binder emulsion may further comprise a pore-forming agent. This pore-forming agent is removed together with the dispersion medium from the binder emulsion, which can contribute greatly to the pore formation of the binder layer. Such pore-former may be at least one selected from the group consisting of aliphatic hydrocarbon-based solvents, vegetable oils, and plasticizers. As such, if the binder emulsion further comprises a pore-forming agent, it further comprises a step of extracting with a suitable solvent.

Finally, the dispersion medium is removed from the binder emulsion coated in step S2 to form a porous binder layer (step S3).

The dispersion medium used can be removed from the binder emulsion using conventional methods known in the art. In this removal process, a drying process may be additionally required. Such drying conditions are possible in a batch or continuous manner using an oven or a heated chamber at a temperature range that takes into account the physical properties of the dispersion medium used.

In particular, in the present invention, the melting temperature (Tm) of the binder emulsion is higher than the drying temperature required to remove the dispersion medium from the binder emulsion. The melting temperature (Tm) of such a specific binder emulsion greatly influences the number, shape, and stability of the pores of the binder layer, thereby achieving a balanced improvement in the performance of the battery due to the porosity of the binder layer and the adhesive force between the electrode and the separator Can be achieved. However, when the melting temperature (Tm) of the binder emulsion is equal to or lower than the removal temperature of the dispersion medium, the binder emulsion is melted to block the pores of the electrode and the separation membrane, leading to deterioration of cell performance. The melting temperature (Tm) of the binder emulsion needs to be higher than the drying temperature necessary for removing the dispersion medium from the binder emulsion. Therefore, if the binder emulsion can be used as a binder layer in the separator, the melting temperature (Tm) And the upper limit value of the temperature difference between the drying temperature of the binder emulsion is not particularly limited.

In addition, the electrode composite of the present invention can be used as an electrode composite of an electrochemical device. Such electrochemical devices include all devices that perform electrochemical reactions, and specific examples thereof include capacitors such as all kinds of primary cells, secondary cells, fuel cells, solar cells, or super capacitor devices. Particularly, a lithium secondary battery including a lithium metal secondary battery, a lithium ion secondary battery, a lithium polymer secondary battery, or a lithium ion polymer secondary battery among the above secondary batteries is preferable.

The electrochemical device can be manufactured according to a conventional method well known in the art. For example, the electrode composite described above, that is, the positive electrode and the negative electrode are assembled through a conventional separation membrane of the related art, .

The separator to be applied together with the electrode composite according to one embodiment of the present invention is not particularly limited and may be formed into a porous form bound with inorganic / organic particles according to a conventional method known in the art.

In addition, a different type of electrode or electrode composite produced according to the manufacturing method of the present invention, that is, a positive electrode composite and a negative electrode composite are disposed so that their porous binder layers are opposed to each other, and winding or laminating An electrochemical device can be manufactured.

Specifically, there is provided an electrochemical device comprising a positive electrode composite having a porous binder layer on one surface, a negative electrode composite having a porous binder layer on one surface thereof, and a separator interposed between the porous binder layer of the positive electrode composite and the porous binder layer of the negative electrode composite Can be provided. In another embodiment, the electrochemical device is a lithium secondary battery.

In addition, the injection of the electrolyte can be performed at an appropriate stage of the battery manufacturing process, depending on the manufacturing process and required properties of the final product. That is, it can be applied before assembling the cell or at the final stage of assembling the cell.

In addition, the electrochemical device of the present invention includes all devices that perform an electrochemical reaction, and specific examples thereof include capacitors such as all kinds of primary cells, secondary cells, fuel cells, solar cells, or super capacitor devices, And so on. Particularly, a lithium secondary battery including a lithium metal secondary battery, a lithium ion secondary battery, a lithium polymer secondary battery, or a lithium ion polymer secondary battery among the above secondary batteries is preferable.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not to be limited to the details thereof and that various changes and modifications will be apparent to those skilled in the art. And various modifications and variations are possible within the scope of the appended claims.

Claims (17)

An electrode current collector coated with an electrode active material on at least one surface thereof; And
A porous binder layer formed of a polyvinylidene fluoride (PVdF) binder, an acrylic binder, or a mixture thereof, coated on the electrode active material layer,
The acrylic binder has a repeating unit derived from a monomer having a first functional group and a repeating unit derived from a monomer having a second functional group,
The monomer having the first functional group may be at least one selected from the group consisting of (meth) acrylic acid, 2- (meth) acryloyloxyacetic acid, 3- (meth) acryloyloxypropyl acid, 4- (meth) acryloyloxybutyric acid, (Meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (Meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyleneglycol (meth) acrylate,
The monomer having the second functional group may be selected from the group consisting of 2 - ((butoxyamino) carbonyloxy) ethyl (meth) acrylate, 2- (diethylamino) ethyl (Meth) acrylate, methyl 2-acetamido (meth) acrylate, 3- (dimethylamino) propyl (meth) acrylate, Acrylamidoglycolic acid, 2- (meth) acrylamido-2-methyl-1-propanesulfonic acid, (3- (meth) acrylamidopropyl) trimethylammonium chloride, N- (Meth) acrylamide, N-tert-butyl (meth) acrylamide, diacetone (meth) acrylamide, (Meth) acrylamide, N, N-dimethyl (meth) acrylamide, N- (isobutoxymethyl) acrylamide, N- (Meth) acrylamide, N, N '- (1,3-phenylene) dimaleimide, N-N'- (Meth) acrylamide and N-vinylpyrrolidinone (N, N'-dicyclohexyl) dimaleimide, N, N'- And at least one member selected from the group consisting of
The porous binder layer has a porosity of 10 to 80%
Wherein the porous binder layer has a thickness of 0.5 to 5 占 퐉.
The method according to claim 1,
Wherein the PVdF binder is selected from the group consisting of polyvinylidene fluoride-co-hexafluoropropylene, polyvinylidene fluoride-co-trichlorethylene, polyvinylidene fluoride-co-tetrafluoroethylene, polyvinylidene fluoride Or a mixture of two or more selected from the group consisting of polyvinylidene fluoride, rye-co-trifluoroethylene, polyvinylidene fluoride-co-trifluorochloroethylene and polyvinylidene fluoride-co- Characterized in that the electrode complex is a mixture of
delete The method according to claim 1,
Wherein the porous binder layer is coated on the active material layer at 40 to 100% of the total area of the electrode active material layer.
The method according to claim 1,
Wherein the porous binder layer further contains a surfactant.
And a separator interposed between the porous binder layer of the positive electrode composite and the porous binder layer of the negative electrode composite, wherein the porous binder layer comprises: a positive electrode composite having a porous binder layer on one surface thereof, a negative electrode composite having a porous binder layer on one surface thereof, The lithium secondary battery according to claim 1,
The method according to claim 1,
Wherein the porous binder layer has a structure in which spherical particles are cross-packed.
Providing an electrode on which an electrode active material layer is formed on at least one side of the electrode current collector;
Coating the electrode active material layer with a binder emulsion comprising a polyvinylidene fluoride (PVdF) binder, an acrylic binder or a mixture thereof, and a dispersion medium; And
And removing the dispersion medium from the coated binder emulsion to form a porous binder layer,
The melting temperature (T _m ) of the binder emulsion is higher than the temperature at which the dispersion medium is removed from the binder emulsion,
The acrylic binder has a repeating unit derived from a monomer having a first functional group and a repeating unit derived from a monomer having a second functional group,
The monomer having the first functional group may be at least one selected from the group consisting of (meth) acrylic acid, 2- (meth) acryloyloxyacetic acid, 3- (meth) acryloyloxypropyl acid, 4- (meth) acryloyloxybutyric acid, (Meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (Meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyleneglycol (meth) acrylate,
The monomer having the second functional group may be selected from the group consisting of 2 - ((butoxyamino) carbonyloxy) ethyl (meth) acrylate, 2- (diethylamino) ethyl (Meth) acrylate, methyl 2-acetamido (meth) acrylate, 3- (dimethylamino) propyl (meth) acrylate, Acrylamidoglycolic acid, 2- (meth) acrylamido-2-methyl-1-propanesulfonic acid, (3- (meth) acrylamidopropyl) trimethylammonium chloride, N- (Meth) acrylamide, N-tert-butyl (meth) acrylamide, diacetone (meth) acrylamide, (Meth) acrylamide, N, N-dimethyl (meth) acrylamide, N- (isobutoxymethyl) acrylamide, N- (Meth) acrylamide, N, N '- (1,3-phenylene) dimaleimide, N-N'- (Meth) acrylamide and N-vinylpyrrolidinone (N, N'-dicyclohexyl) dimaleimide, N, N'- And at least one selected from the group consisting of
7. A method for producing an electrode composite according to any one of claims 1, 5, and 7.
9. The method of claim 8,
Wherein the thickness of the porous binder layer is 0.5 to 5 占 퐉.
9. The method of claim 8,
Wherein the PVdF binder is selected from the group consisting of polyvinylidene fluoride-co-hexafluoropropylene, polyvinylidene fluoride-co-trichlorethylene, polyvinylidene fluoride-co-tetrafluoroethylene, polyvinylidene fluoride Or a mixture of two or more selected from the group consisting of polyvinylidene fluoride, rye-co-trifluoroethylene, polyvinylidene fluoride-co-trifluorochloroethylene and polyvinylidene fluoride-co- Wherein the electrode composite is formed by a method comprising the steps of:
delete 9. The method of claim 8,
Wherein the dispersion medium is acetone, tetrahydrofuran, methylene chloride, chloroform, dimethylformamide, N-methyl-2-pyrrolidone (NMP), cyclohexane, water or a mixture thereof .
9. The method of claim 8,
Wherein the binder emulsion further comprises a pore-forming agent.
14. The method of claim 13,
Wherein the pore-forming agent is at least one selected from the group consisting of aliphatic hydrocarbon-based solvents, vegetable oils, and plasticizers.
14. The method of claim 13,
Further comprising the step of extracting the pore-forming agent with a solvent.
9. The method of claim 8,
Wherein the region where the porous binder layer contacts the electrode active material layer is 40 to 100% of the total area of the electrode active material layer.
9. The method of claim 8,
Wherein the binder in the binder emulsion is a polyvinylidene fluoride (PVdF) binder and the dispersion medium is a water.