Binder, method for manufacturing same, electrode comprising same, secondary battery comprising same, and capacitor comprising same

Abstract

The present invention relates to: a binder containing polymer particles each including a core portion and a shell portion, wherein the shell portion includes an epoxy-containing (meth)acrylate monomer and a (meth)acrylamide monomer, the molar content of the epoxy-containing (meth)acrylate monomer is 0.1-10 mol% on the basis of the entire shell portion, the molar content of the (meth)acrylamide monomer is 0.1-10 mol% on the basis of the entire shell portion, and the molar content of the (meth)acrylamide monomer is 5-190% on the basis of the total molar content of the epoxy-containing (meth)acrylate monomer; a method for manufacturing same; an electrode comprising same; a secondary battery comprising same; and a capacitor comprising same.

Description

Binder, method for manufacturing same, electrode including same, secondary battery including same, capacitor including same

[0001] This specification claims the benefit of patent application Ser. No. 10-2023-0156156, filed with the Korean Intellectual Property Office on November 13, 2023, the contents of which are incorporated herein by reference.

[0002] The present invention relates to a binder, a method for producing the same, an electrode comprising the same, a secondary battery comprising the same, and a capacitor comprising the same.

[0003] With the recent increase in demand for electric vehicles and mobile devices, secondary batteries are attracting attention as power sources for their operation. Among these secondary batteries, lithium secondary batteries offer high energy density and voltage while being lightweight, and their rapid charging capabilities have led to active research and widespread commercialization.

[0004] Similarly, capacitors that utilize an electric double layer formed at the interface between polarized electrodes and electrolytes are used for large-capacity storage functions such as memory backup power or power for electric vehicles.

[0005] Lithium secondary batteries or electric double layer capacitors contain one or more electrodes having a structure in which an electrode active material is bound to a current collector by a binder, and a separator, electrolyte, etc. are placed between these electrodes, and electricity is generated, stored, or consumed by a redox reaction due to insertion and deintercalation of ions between the electrodes or by physical bonding by ions or electrons at the interface between the electrode and the electrolyte.

[0006] Here, the binder binds the active material of the electrode and sometimes also binds additives, such as conductive materials, added separately to enhance conductivity. The binder must maintain stable adhesive properties even in the harsh electrochemical environment of contact with the electrolyte and redox reactions. Furthermore, for medium- to large-sized batteries that require operation for more than 10 years, ensuring the reliability of the polymer binder material is crucial.

[0007] Currently, organic fluorine polymer binders such as polyvinylidene fluoride (PVdF) and polytetrafluoroethylene, and aqueous polymer binders such as styrene butadiene rubber (SBR) are being used commercially. However, there is still a need for the development of binders that have low electrical resistance and have the binding strength and mechanical properties to withstand volume changes such as volume expansion of active materials during charge and discharge of electrochemical devices.

[0008] [Prior Art Literature]

[0009] [Patent Document]

[0010] Korean Patent No. 10-0491026 (May 13, 2005)

[0011] The present specification relates to a binder, a method for manufacturing the same, an electrode including the same, a secondary battery including the same, and a capacitor including the same.

[0012] One embodiment of the present invention comprises a polymer particle including a core portion and a shell portion,

[0013] The above shell portion comprises a (meth)acrylate monomer and a (meth)acrylamide monomer including epoxy,

[0014] The molar content of the (meth)acrylate monomer including the above epoxy is 0.1 mol% or more and 10 mol% or less based on the entire shell portion,

[0015] The molar ratio of the above (meth)acrylamide monomer is 0.1 mol% or more and 10 mol% or less based on the entire shell portion,

[0016] A binder is provided in which the molar content of the (meth)acrylamide monomer is 5% or more and 190% or less based on the total molar content of the (meth)acrylate monomer including the epoxy.

[0017] One embodiment of the present invention comprises the steps of manufacturing a core portion including core polymer particles; and

[0018] A method for manufacturing the above-described binder is provided, comprising a step of mixing a shell polymer solution and the core portion to form a shell portion on the outer surface of the core portion.

[0019] One embodiment of the present invention provides an electrode comprising the above-described binder and an electrode active material.

[0020] One embodiment of the present invention provides a secondary battery including the electrode.

[0021] One embodiment of the present invention provides a capacitor including the electrode.

[0022] A binder according to one embodiment of the present invention has the advantage of excellent bonding strength to an electrode member.

[0023] Hereinafter, the present invention will be described in detail.

[0024] Typically, during charging and discharging, a battery experiences volume expansion, which in turn generates stress. This stress can cause cracks in the electrodes, and irreversible damage occurs at the crack surfaces. Meanwhile, if the bonding strength of the electrodes is weak, detachment of the electrodes from the current collector during charging and discharging cannot be prevented. Consequently, repeated charging and discharging can degrade the cycle performance.

[0025] The present inventors have confirmed that, in a binder having a core portion and a shell portion, by controlling the content or molar content ratio of the monomer included in the shell portion, the binding force or binding force of the binder to an electrode member is improved, and have completed the present invention.

[0026] One embodiment of the present invention comprises a polymer particle including a core portion and a shell portion,

[0027] The above shell portion comprises a (meth)acrylate monomer and a (meth)acrylamide monomer including epoxy,

[0028] The molar content of the (meth)acrylate monomer including the above epoxy is 0.1 mol% or more and 10 mol% or less based on the entire shell portion,

[0029] The molar ratio of the above (meth)acrylamide monomer is 0.1 mol% or more and 10 mol% or less based on the entire shell portion,

[0030] A binder is provided in which the molar content of the (meth)acrylamide monomer is 5% or more and 190% or less based on the total molar content of the (meth)acrylate monomer including the epoxy.

[0031] In one embodiment of the present invention, the molar content of the (meth)acrylamide monomer may be 5% or more and 190% or less based on the total molar content of the (meth)acrylate monomer including the epoxy. Specifically, it may be 10% or more and 150% or less, 30% or more and 150% or less, 40% or more and 150% or less, 70% or more and 130% or less, or 90% or more and 120% or less. In the above numerical range, the binding force of the binder to the electrode member or the binding force thereof is improved.

[0032] In one embodiment of the present invention, the molar content of the (meth)acrylate monomer including the epoxy may be 0.1 mol% or more and 10 mol% or less based on the entire shell portion. Specifically, it may be 0.1 mol% or more and 5 mol% or less, 0.1 mol% or more and 2 mol% or less, 0.2 mol% or more and 1 mol% or less, or 0.3 mol% or more and 0.9 mol% or less. Within the above numerical range, the binding force of the binder to the electrode member is improved.

[0033] In one embodiment of the present invention, the molar content of the (meth)acrylamide monomer may be 0.1 mol% or more and 10 mol% or less based on the entire shell portion. Specifically, it may be 0.1 mol% or more and 5 mol% or less, 0.1 mol% or more and 2 mol% or less, 0.2 mol% or more and 1 mol% or less, or 0.3 mol% or more and 0.9 mol% or less. In the above numerical range, the binding force of the binder to the electrode member or the binding force thereof is improved.

[0034] A binder according to one embodiment of the present invention comprises a (meth)acrylate monomer containing epoxy. This can improve the crosslinking degree of the binder.

[0035] In one embodiment of the invention, the (meth)acrylate monomer including the epoxy may include glycidyl methacrylate.

[0036] A binder according to one embodiment of the present invention comprises a (meth)acrylamide monomer.

[0037] In one embodiment of the present invention, the (meth)acrylamide monomer may include acrylamide, n-methylolacrylamide, n-butoxymethylacrylamide, methacrylamide, or a combination thereof.

[0038] In one embodiment of the present invention, the shell portion may include a repeating unit derived from a (meth)acrylic acid ester monomer, a monomer having a nitrile group, an acrylic monomer having a functional group, or a combination thereof.

[0039] In one embodiment of the present invention, a functional group can be introduced into a copolymer included in the shell portion through a functional group of an acrylic monomer having the functional group, and through this, the bonding strength between the core portion and the shell portion can be improved.

[0040] In one embodiment of the present invention, the (meth)acrylic acid ester monomer may include a C1 to C6 alkyl group. In addition, the alkyl group may be 1 or 2 or more. Specifically, it may include methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, butyl acrylate, isobutyl acrylate, 2-ethylhexyl acrylate, or n-hexyl acrylate.

[0041] In one embodiment of the present invention, the (meth)acrylic acid ester monomer may include butyl (meth)acrylate. The butyl (meth)acrylate has a short alkyl group chain length, a low glass transition temperature (Tg), and flexibility, and thus has the property of maintaining high binding force. The butyl (meth)acrylate may refer to butyl acrylate or butyl methacrylate.

[0042] In one embodiment of the present invention, the monomer having the nitrile group may include acrylonitrile, methacrylonitrile, cyanoalkyl acrylate, or a mixture thereof.

[0043] In one embodiment of the present invention, the acrylonitrile has a high glass transition temperature (Tg) and hard properties, and thus has excellent tensile strength.

[0044] In one embodiment of the present invention, the cyanoalkyl acrylate means an acrylate substituted with an alkyl group and a cyano group, and the carbon number of the alkyl group is not particularly limited, but may be an alkyl group of C1 to C6.

[0045] In one embodiment of the present invention, the cyanoalkyl acrylate may be 2-cyanobutyl acrylate or 2-cyanoethyl acrylate.

[0046] In one embodiment of the present invention, the functional group may be at least one selected from the group consisting of a hydroxyl group, a carboxyl group, an amide group, an amino group, and a sulfonic acid group.

[0047] In one embodiment of the present invention, the acrylic monomer having the functional group may include at least one selected from the group consisting of maleic acid, fumaric acid, methacrylic acid, acrylic acid, glutaconic acid, itaconic acid, tetrahydrophthalic acid, crotonic acid, isocrotonic acid, and nadic acid.

[0048] In one embodiment of the present invention, the content of the monomer having a nitrile group may be 10 mol% or more and 200 mol% or less based on the total mole number of the (meth)acrylic acid ester monomer. Preferably, it may be 40 mol% or more and 150 mol% or less, or 50 mol% or more and 100 mol% or less. The (meth)acrylic acid ester monomer may have a soft property due to a low glass transition temperature (Tg), whereas the monomer having a nitrile group may have a relatively hard property due to a high glass transition temperature (Tg). At this time, by controlling the hard property and the soft property, the bonding strength of the shell portion and the core portion can be maintained excellently.

[0049] In one embodiment of the present invention, the content of the acrylic monomer having the functional group may be 0.1 mol% or more and 10 mol% or less based on the total mole number of the (meth)acrylic acid ester monomer. Preferably, it may be 1 mol% or more and 8 mol% or less or 2 mol% or more and 6 mol% or less. When the above weight range is satisfied, the functional group included in the shell portion is sufficient, so that the bonding force between the shell portion and the core portion can be maintained excellently.

[0050] In one embodiment of the present invention, the core portion may include a repeating unit derived from an aromatic vinyl monomer.

[0051] In one embodiment of the present invention, the aromatic vinyl monomer may include at least one selected from the group consisting of styrene, α-methylstyrene, β-methylstyrene, pt-butylstyrene, chlorostyrene, vinylbenzoic acid, methyl vinylbenzoate, vinylnaphthalene, chloromethylstyrene, hydroxymethylstyrene, and divinylbenzene.

[0052] In one embodiment of the present invention, the core portion may include, in addition to the aromatic vinyl monomer, a repeating unit derived from at least one monomer selected from the group consisting of an acrylate monomer, a (meth)acrylic acid ester monomer, a vinyl monomer, a nitrile monomer, and an unsaturated carboxylic acid monomer.

[0053] In one embodiment of the present invention, the weight ratio of the core portion to the total weight of the polymer particles may be 1 wt% or more and 28 wt% or less. Preferably, it may be 1 wt% or more and 25 wt% or less, 2 wt% or more and 20 wt% or less, or 3 wt% or more and 15 wt% or less. When the above numerical range is satisfied, the structural stability of the core portion and the shell portion is improved, and the binding force of the binder to the substrate can be enhanced.

[0054] In one embodiment of the present invention, the average diameter of the polymer particles may be 100 nm or more and 500 nm or less. Preferably, it may be 110 nm or more and 400 nm or less, 130 nm or more and 300 nm or less, or 150 nm or more and 200 nm or less. When the above numerical ranges are satisfied, the structural stability of the core and shell portions can be improved, and the bonding strength to the substrate can be enhanced.

[0055] In one embodiment of the present invention, the average diameter of the core portion may be 10 nm or more and 95 nm or less. Preferably, it may be 20 nm or more and 90 nm or less, 30 nm or more and 80 nm or less, or 40 nm or more and 70 nm or less. When the above numerical ranges are satisfied, the structural stability of the core portion and the shell portion can be improved, and the bonding strength to the substrate can be enhanced.

[0056] In one embodiment of the present invention, the ratio of the average diameter of the core portion to the average diameter of the polymer particles may be 5% or more and 90% or less. Preferably, it may be 10% or more and 60% or less, 20% or more and 50% or less, or 30% or more and 40% or less. When the above numerical range is satisfied, the structural stability of the core portion and the shell portion is improved, and the binding force of the binder to the substrate can be enhanced.

[0057] One embodiment of the present invention provides an electrode including the binder and an electrode active material.

[0058] In one embodiment of the present invention, the electrode may further include a conductive material.

[0059] In one embodiment of the present invention, the electrode may include an electrode slurry including at least one of the binder, electrode active material, and conductive material.

[0060] In one embodiment of the present invention, the content of the binder may be 1 part by weight to 30 parts by weight based on the total weight of the electrode slurry.

[0061] In one embodiment of the present invention, the electrode may be an anode or a cathode.

[0062] In one embodiment of the present invention, the electrode may be a cathode.

[0063] In one embodiment of the present invention, the electrode may include activated carbon.

[0064] One embodiment of the present invention provides a secondary battery including the electrode.

[0065] One embodiment of the present invention provides a capacitor including the electrode.

[0066] In one embodiment of the present invention, the electrode can be used in a lithium ion secondary battery, a lithium metal secondary battery, a fuel cell, a solar cell, or a supercapacitor in addition to a secondary battery and a capacitor.

[0067] One embodiment of the present invention provides a method for producing the above-described binder, comprising the steps of producing a core portion including core polymer particles; and mixing a shell polymer solution with the core portion to form a shell portion on the outer surface of the core portion.

[0068] In one embodiment of the present invention, the step of manufacturing a core portion; and the step of forming a shell portion on the outer surface of the core portion may be performed by emulsion polymerization. That is, the step of manufacturing the core portion through a first emulsion polymerization may be performed, and the step of forming a shell portion on the outer surface of the core portion may be performed through a second emulsion polymerization.

[0069] In one embodiment of the present invention, the step of manufacturing the core part and the step of forming a shell part on the outer surface of the core part may be performed at different temperatures, and may be performed at a polymerization temperature of 50°C to 200°C or 50°C to 100°C, respectively.

[0070] In one embodiment of the present invention, the step of manufacturing the core portion; and the step of forming a shell portion on the outer surface of the core portion may be performed for different times, and may be performed for 30 minutes to 24 hours or 1 hour to 10 hours, respectively.

[0071] In one embodiment of the present invention, the step of manufacturing the core part can be manufactured by polymerizing a core polymer solution.

[0072] In one embodiment of the present invention, the core polymer solution may include an aromatic vinyl monomer.

[0073] In one embodiment of the present invention, the core polymer solution may include one or more additives selected from the group consisting of a polymerization initiator, an activator, and an emulsifier.

[0074] In one embodiment of the present invention, the shell polymer solution may include a (meth)acrylic acid ester monomer, a monomer having a nitrile group, an acrylic monomer having a functional group, or a combination thereof.

[0075] In one embodiment of the present invention, the shell polymer solution may include a (meth)acrylic acid ester monomer, a monomer having a nitrile group, and an acrylic monomer having a functional group.

[0076] In one embodiment of the present invention, the shell polymer solution may include one or more additives selected from the group consisting of a polymerization initiator, an activator, and an emulsifier.

[0077] In one embodiment of the present invention, the polymerization initiator may be an inorganic or organic peroxide, and for example, a water-soluble initiator including potassium persulfate, sodium persulfate, ammonium persulfate, etc., and an oil-soluble initiator including cumene hydroperoxide, benzoyl peroxide, etc. may be used.

[0078] In one embodiment of the present invention, the activator may include at least one selected from the group consisting of sodium formaldehyde sulfoxylate, sodium ethylenediaminetetraacetate, ferrous sulfate, and dextrose.

[0079] In one embodiment of the present invention, the emulsifier has both a hydrophobic group portion and a hydrophilic group portion, and when the emulsifier is dispersed in a solution, the hydrophilic group is dispersed toward the water, which is the dispersion medium, and the hydrophobic group is dispersed toward the monomer phase, which is the organic phase. At this time, by forming micelles, a space for polymerization of the monomer is provided, and emulsifier molecules that do not form micelles surround the polymerized polymer particles and prevent collisions between the particles, thereby preventing the particles from agglomerating.

[0080] In one embodiment of the present invention, the emulsifier is selected from the group consisting of lauryl sulfate-based emulsifiers such as sodium lauryl sulfate (SLS), ammonium lauryl sulfate, and potassium lauryl sulfate; sulfate-based emulsifiers such as sodium dodecyl sulfate (SDS); nonionic emulsifiers such as polyoxyethylene nonylphenyl ether, polyoxyethylene sorbitan lauryl ester, and polyoxyethylene-polyoxypropylene block copolymers; gelatin, maleic anhydride-ethylene copolymer, and polyvinylpyrrolidone; sodium benzenesulfonic acid salts such as sodium dodecylbenzenesulfonate and sodium dodecylphenyl ethersulfonate; sodium alkyl sulfate salts such as sodium lauryl sulfate and sodium tetradodecyl sulfate; sodium sulfosuccinate salts such as sodium dioctyl sulfosuccinate and sodium dihexyl sulfosuccinate; Fatty acid sodium salts such as sodium laurate; ethoxysulfate sodium salts such as polyoxyethylene lauryl ether sulfate sodium salt and polyoxyethylene nonylphenyl ether sulfate sodium salt; alkyl ether phosphate sodium salt; sodium polyacrylate, etc. can be used alone or in combination of two or more.

[0081] Hereinafter, the present invention will be described in detail through examples.

[0082] <Example 1>

[0083] 2.5 g of emulsifier sodium lauryl sulfate (SLS) and 395 g of distilled water were added to the reactor, and 75 g of styrene monomer was added at once, heated to 75°C, and purged with nitrogen. When the reactor temperature reached 75°C, an initiator solution containing 0.2 g of initiator ammonium persulfate (APS) mixed with distilled water was added, stirred for 2 hours, and then the reactor temperature was increased to 85°C, and the reaction was continued for another 2 hours. After cooling to room temperature to terminate the reaction, a core solution containing polystyrene polymer having an average diameter of approximately 67 nm and a total solid concentration (TSC) of 15% was manufactured.

[0084] 237 g of distilled water and the above core solution were injected into the reactor at a ratio of 3 wt% based on solid content, and the internal conditions of the reactor were purged with nitrogen gas and the temperature was raised to 80°C. When the reactor temperature reached 80℃, an initiator solution containing 0.6 g of ammonium persulfate (APS) in distilled water was added, stirred with the solution inside the reactor, and shell monomers butylacrylate (BA) 30.5 mol%, acrylonitrile (AN) 35.5 mol%, butyl methacrylate (BMA) 25.0 mol%, 2-ethylhexylacrylate (2-EHA) 5 mol%, methacrylic acid (MAA) 1.5 mol%, acrylic acid (AA) 1.5 mol%, acrylamide (AAm) 0.5 mol%, and glycidyl methacrylate (GMA) 0.5 mol% were continuously added using a quantitative pump for 3 hours. After that, the reactor temperature was increased to 85℃, and the reaction was continued for 3 hours, and then cooled to room temperature to terminate the shell polymerization reaction.

[0085] Afterwards, 5 wt% NaHCO3 aqueous solution was added to the above polymer to adjust the pH to 7, and then the TSC was adjusted to 40% through reflux to manufacture a binder with an average diameter of 180 nm.

[0086] <Examples and Comparative Examples>

[0087] A binder was prepared in the same manner as in Example 1, except that the molar ratio of the (meth)acrylate monomer and (meth)acrylamide monomer containing epoxy was changed as shown in Table 1 below.

[0088] Experimental Example 1

[0089] An experiment was conducted to measure the bonding strength between the negative electrode composition and the current collector when the binder according to the examples and comparative examples was used in the negative electrode. In order to prepare a specimen for measuring the bonding strength, an electrode composition was prepared by mixing 1.4 wt% of the binder of the comparative examples and examples, 2 wt% of the conductive agent, 95.6 wt% of the negative electrode active material, and 1 wt% of carboxymethyl cellulose (CMC) at a loading level of 6 (6 mg / cm 2 ) and dried at 80 ℃ for 30 minutes and 100 ℃ in a vacuum for 30 minutes, respectively. The dried electrode was cut into 4 cm wide pieces and pressed to about 30% of the electrode thickness to prepare an electrode specimen, then double-sided tape (manufactured by Hyesung, width 4.5 cm) was attached to a stainless steel substrate and the slurry-visible side of the electrode specimen was attached onto the double-sided tape. Afterwards, in order to increase the fixing force, a pressing device (2 kgf rubber roller, KS T 1028) was used at room temperature, and only the weight of the roller was used without external pressure, and the pressing speed was 300 mm / min twice back and forth to fix the electrode plate and the stainless steel substrate, and only the current collector part was caught on a stainless steel jig and the current collector was peeled off at a speed of 300 mm / min in 180° peel test mode. At this time, the Texture Analyzer (model name TXA-precision) of Yeonjin S-Tech Co., Ltd. was used, the specification of the load cell used was 1 kgf, and all peel tests were performed under standard conditions (room temperature (RT), atmospheric pressure). The results of measuring the 180° peel strength using this evaluation method are shown in Table 1 below. The peel strength of five samples was measured and determined as the average value.

[0090] Experimental Example 2

[0091] Approximately 6 g of the manufactured binder was collected and dried at 80°C for more than 16 hours to obtain a binder film. The film was then cut to the same size using a 14pi puncher, immersed in 10 ml of an electrolyte consisting of EC:EMC = 3:7, left for 3 days, and then taken out and dried at 80°C. The volume change rate before and after drying was determined.

[0092] ClassificationExample 1Example 2Example 3Comparative Example 1Comparative Example 2Comparative Example 3Comparative Example 4Composition (a) 0.510.50.50.250.50.25Composition (b) 0.50.250.251133Weight ratio (b) / (a)*100(%)100%25%50%200%400%600%1,200%Experimental Example 1Adhesion (N) 2.0331.9051.8091.7921.7641.5481.647Experimental Example 2Volume change rate 300%245%300%300%637%300%525%

[0093] * In Table 1, (a) is a (meth)acrylate monomer containing epoxy, and (b) is a (meth)acrylamide monomer.

[0094] From the above results, it was confirmed that the binder of the example in which the molar content of the (meth)acrylate monomer including epoxy was adjusted to be 0.1 mol% or more and 10 mol% or less based on the entire shell portion, the molar content of the (meth)acrylamide monomer was adjusted to be 0.1 mol% or more and 10 mol% or less based on the entire shell portion, and the molar content of the (meth)acrylamide monomer was adjusted to be 5% or more and 190% or less based on the entire molar content of the (meth)acrylate monomer including epoxy had high binding power and a small volume change rate (Examples 1 to 3).

[0095] However, it was confirmed that the bonding strength decreased when the molar content of the (meth)acrylamide monomer exceeded 190% based on the total molar content of the (meth)acrylate monomer containing epoxy (Comparative Examples 1 to 4).

Claims

1. Comprising a polymer particle including a core portion and a shell portion, The above shell portion comprises a (meth)acrylate monomer and a (meth)acrylamide monomer including epoxy, The molar content of the (meth)acrylate monomer including the above epoxy is 0.1 mol% or more and 10 mol% or less based on the entire shell portion, The molar content of the above (meth)acrylamide monomer is 0.1 mol% or more and 10 mol% or less based on the entire shell portion, A binder wherein the molar content of the (meth)acrylamide monomer is 5% or more and 190% or less based on the total molar content of the (meth)acrylate monomer containing the epoxy.

2. In claim 1, A binder comprising the (meth)acrylate monomer including the above epoxy, wherein the (meth)acrylate monomer comprises glycidyl methacrylate.

3. In claim 1, A binder wherein the above (meth)acrylamide monomer comprises acrylamide, n-methylolacrylamide, n-butoxymethylacrylamide, methacrylamide or a combination thereof.

4. In claim 1, A binder wherein the shell portion comprises a repeating unit derived from a (meth)acrylic acid ester monomer, a monomer having a nitrile group, an acrylic monomer having a functional group, or a combination thereof.

5. In claim 4, A binder wherein the above (meth)acrylic acid ester monomer contains an alkyl group of C1 to C6.

6. In claim 4, A binder wherein the above (meth)acrylic acid ester monomer comprises butyl (meth)acrylate.

7. In claim 4, A binder wherein the monomer having the nitrile group comprises acrylonitrile, methacrylonitrile, cyanoalkyl acrylate or a mixture thereof.

8. In claim 4, A binder wherein the functional group is at least one selected from the group consisting of a hydroxy group, a carboxyl group, an amide group, an amino group, and a sulfonic acid group.

9. In claim 4, A binder comprising an acrylic monomer having the above functional group, wherein the acrylic monomer comprises at least one selected from the group consisting of maleic acid, fumaric acid, methacrylic acid, acrylic acid, glutaconic acid, itaconic acid, tetrahydrophthalic acid, crotonic acid, isocrotonic acid, and nadic acid.

10. In claim 1, A binder wherein the core portion comprises a repeating unit derived from an aromatic vinyl monomer.

11. A step of manufacturing a core part including core polymer particles; and It includes a step of forming a shell part on the outer surface of the core part by mixing the shell polymer solution and the core part. A method for manufacturing a binder according to any one of claims 1 to 10.

12. An electrode comprising a binder according to any one of claims 1 to 10; and an electrode active material.

13. In claim 12, The above electrode is a cathode electrode.

14. A secondary battery comprising an electrode according to claim 12.

15. A capacitor comprising an electrode according to claim 12.