Method for manufacturing electrode for secondary battery using insulating composition including aqueous binder substituted with non-aqueous solvent

Abstract

The present invention relates to a method for manufacturing an electrode for a secondary battery.SOLUTION: By manufacturing the electrode using the insulating composition including the aqueous binder substituted with the non-aqueous organic solvent, it is possible to increase the wet adhesion of the insulating layer and to prevent gelation due to the application of the heterogeneous binder between the electrode slurry and the insulating composition.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2021-0113557, filed August 27, 2021, and Korean Patent Application No. 10-2022-0090828, filed July 22, 2022, and all contents disclosed in the documents of said Korean patent applications are incorporated herein by reference.

[0002] The present invention relates to a method for producing an electrode for a secondary battery using an insulating composition containing an aqueous binder substituted with a non-aqueous solvent. [Background technology]

[0003] With the increasing technological development and demand for mobile devices, the demand for secondary batteries as an energy source is rapidly increasing, and as a result, much research is being conducted on batteries that can meet various needs.

[0004] In terms of battery shape, there is a high demand for prismatic and pouch-type batteries that are thin and applicable to products such as mobile phones, and in terms of materials, there is a high demand for lithium secondary batteries such as lithium cobalt polymer batteries, which have excellent energy density, discharge voltage, and safety.

[0005] One of the main research topics for secondary batteries is improving their safety. The primary cause of safety-related battery accidents is abnormally high temperatures caused by short circuits between the positive and negative electrodes. Under normal circumstances, a separator is positioned between the positive and negative electrodes to maintain electrical insulation. However, under abnormal conditions, such as overcharging or overdischarging of a battery, internal short circuits caused by dendritic growth of electrode materials or foreign objects, penetration of the battery by a sharp object such as a nail, or excessive deformation of the battery due to external force, conventional separators reach their limits in maintaining electrical insulation.

[0006] As a complementary measure to prevent internal short circuits in batteries, methods have been proposed to form an insulating layer by attaching insulating tape to the boundary line between the uncoated and coated areas of the electrode or by coating an insulating liquid. For example, an insulating layer is formed by applying an insulating binder to the boundary line between the uncoated and coated areas of the positive electrode or by coating an insulating liquid in which a mixture of the binder and inorganic particles is dispersed in a solvent.

[0007] Previously, non-aqueous binders (e.g., PVDF) were used for the positive electrode insulating layer. However, the adhesive strength of these insulating layers (hereinafter referred to as wet adhesive strength) decreased when immersed in an electrolyte, resulting in the inability to prevent lithium ions from migrating to the electrode overlay area, resulting in a problem of low capacity (see Figure 1). Therefore, research has been conducted into the use of aqueous binders, such as styrene-butadiene rubber, for the positive electrode insulating layer. However, coating with aqueous binders such as styrene-butadiene rubber requires the use of water as a solvent. However, applying water as a solvent to a positive electrode, which is sensitive to moisture, is difficult, resulting in the problem of gelation between the binder and the positive electrode slurry. Summary of the Invention [Problem to be solved by the invention]

[0008] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a method for producing an electrode for a secondary battery using an insulating composition containing an aqueous binder substituted with a non-aqueous solvent. [Means for solving the problem]

[0009] In order to solve the above-mentioned problems, in one embodiment, a method for producing an electrode for a secondary battery according to the present invention includes: applying an electrode slurry containing an electrode active material, a conductive material, and a non-aqueous binder to one or both surfaces of a current collector; applying an insulating composition including an aqueous binder substituted with a non-aqueous solvent so as to cover a portion of the electrode slurry applied to the current collector from a portion of the uncoated portion of the current collector; and drying the electrode slurry and the insulating composition applied to the current collector. The electrode slurry and the insulating composition each contain the same or the same type of non-aqueous organic solvent.

[0010] In one embodiment, the steps of applying the electrode slurry and applying the insulating composition satisfy the following formula 1:

[0011] [Formula 1] 0≦T2-T1≦100 (seconds)

[0012] In formula 1, T1 means the time (seconds) at which the electrode slurry is discharged from the slot die coater onto the current collector in the step of applying the electrode slurry, T2 means the time (seconds) at which the insulating composition is discharged onto the current collector from the slot die coater in the step of applying the insulating composition.

[0013] At this time, the step of applying the insulating composition may be performed in a state where the electrode slurry applied to the current collector is not dried.

[0014] The non-aqueous organic solvent may be one selected from the group consisting of N-methyl-pyrrolidone (NMP), dimethylformamide (DMF), dimethylacetamide (DMAc), dimethyl sulfoxide (DMSO), ethylene carbonate (EC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), dimethyl carbonate (DMC), propylene carbonate (PC), dipropyl carbonate (DPC), butylene carbonate (BC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), acetonitrile, dimethoxyethane, tetrahydrofuran (THF), gamma-butyrolactone, methyl alcohol, ethyl alcohol, and isopropyl alcohol.

[0015] The insulating composition may further include inorganic particles.

[0016] Specifically, the inorganic particles may be one or more selected from the group consisting of AlOOH, Al2O3, γ-AlOOH, Al(OH)3, Mg(OH)2, Ti(OH)4, MgO, CaO, Cr2O3, MnO2, Fe2O3, Co3O4, NiO, ZrO2, BaTiO3, SnO2, CeO2, Y2O3, SiO2, silicon carbide (SiC), and boron nitride (BN).

[0017] In this case, the weight ratio of the inorganic particles to the aqueous binder in the insulating composition may be within a range of 1:99 to 95:5.

[0018] The non-aqueous binder may be one or more selected from the group consisting of polyvinylidene fluoride (PVDF), polyvinylidene fluoride-co-hexafluoropropene (PVDF-co-HFP), poly(ethylene oxide) (PEO), polyacrylic acid (PAA), polyimide (PI), polyamideimide (PAI), and polyimide-polyamideimide copolymer (PI-PAI).

[0019] The aqueous binder may also be one or more selected from the group consisting of styrene-butadiene rubber, acrylate styrene-butadiene rubber, acrylonitrile-butadiene rubber, acrylonitrile-butadiene-styrene rubber, acrylic rubber, butyl rubber, fluororubber, polytetrafluoroethylene, polyethylene, polypropylene, ethylene propylene copolymer, polyethylene oxide, polyvinylpyrrolidone, polyepichlorohydrin, polyphosphazene, polyacrylonitrile, polystyrene, ethylene propylene diene copolymer, polyvinylpyridine, chlorosulfonated polyethylene, latex, polyester resin, acrylic resin, phenol resin, epoxy resin, polyvinyl alcohol, hydroxypropyl methylcellulose, hydroxypropyl cellulose, and diacetyl cellulose.

[0020] In one embodiment, the insulating composition includes an aqueous binder substituted with a non-aqueous solvent and inorganic particles dispersed in the aqueous binder matrix substituted with the non-aqueous solvent. Specifically, the weight ratio of the inorganic particles to the aqueous binder is in the range of 1:99 to 95:5. The insulating composition has a viscosity at 25°C in the range of 50 cP to 50,000 cP.

[0021] In a specific example, the non-aqueous organic solvent may be N-methyl-pyrrolidone (NMP) and the aqueous binder may be styrene-butadiene rubber (SBR).

[0022] In addition, the step of drying the electrode slurry and insulating composition applied to the current collector may be performed at an average temperature ranging from 50°C to 300°C.

[0023] The steps of applying the electrode slurry and applying the insulating composition can be performed using a slot die coater. In one example, the steps of applying the electrode slurry and applying the insulating composition are performed using a single die coater including two slots. In this case, the die coater has a structure including an electrode slurry discharge slot and an insulating composition discharge slot.

[0024] In yet another example, the steps of applying the electrode slurry and applying the insulating composition are performed using two separate die coaters. In this case, the step of applying the insulating composition is performed before the electrode slurry dispensed in the step of applying the electrode slurry dries. [Effects of the Invention]

[0025] According to the method for manufacturing an electrode for a secondary battery according to the present invention, it is possible to use an aqueous binder with excellent wet adhesion when forming an insulating layer, while preventing gelation due to the use of different binders between the electrode slurry and the insulating composition. [Brief explanation of the drawings]

[0026] [Figure 1] FIG. 1 is a diagram showing a schematic diagram of lithium ion migration in the overlay region of an electrode. [Figure 2] 1 is a flowchart showing a method for manufacturing an electrode for a secondary battery according to the present invention. [Figure 3] 3 is a photograph showing the electrode slurry and the insulating composition produced in Comparative Example 1 simultaneously coated before and after drying. [Figure 4] 3 is a photograph showing the electrode slurry and the insulating composition produced in Example 1 simultaneously coated before and after drying. [Figure 5] FIG. 10 is a diagram showing the results of measuring the wet adhesive strength of insulating layers of an example and a comparative example. [Figure 6] 1 is a graph showing the results of measuring the discharge capacity to evaluate the capacity development of the battery cells of Examples 5 to 7 (room temperature discharge characteristics). [Figure 7] 1 is a graph showing the results of measuring the discharge capacity to evaluate the capacity development of the battery cells of Examples 5 to 7 (high-temperature discharge characteristics). DETAILED DESCRIPTION OF THE INVENTION

[0027] While the present invention is susceptible to various modifications and may have various embodiments, specific examples will be described in detail.

[0028] However, it should be understood that this is not intended to limit the invention to any particular embodiment, but rather to include all modifications, equivalents, or alternatives falling within the spirit and scope of the invention.

[0029] In the present invention, the terms "comprise" or "have" and the like are intended to specify the presence of features, numbers, steps, operations, components, parts or combinations thereof described in the specification, and should be understood as not precluding the presence or possible addition of one or more other features, numbers, steps, operations, components, parts or combinations thereof.

[0030] Furthermore, in the present invention, when a layer, film, region, plate, or other portion is described as being "on" another portion, this includes not only the case where it is "directly on" the other portion, but also the case where there is another portion in between. Conversely, when a layer, film, region, plate, or other portion is described as being "under" the other portion, this includes not only the case where it is "directly under" the other portion, but also the case where there is another portion in between. Furthermore, in the present application, being "located on" may include not only the case where it is located at the top, but also the case where it is located at the bottom.

[0031] In the present invention, the term "insulating layer" refers to an insulating member formed by applying and drying from at least a portion of the uncoated portion of the electrode current collector to at least a portion of the electrode mixture layer.

[0032] In the present invention, the term "wet adhesion" refers to the adhesion of an insulating layer measured in a state where the insulating layer is immersed in an electrolyte. More specifically, the wet adhesion can be measured by immersing a metal test piece having an insulating layer formed thereon in an electrolyte, applying ultrasonic waves, and then checking for swelling or detachment of the insulating layer.

[0033] In the present invention, the term "metal test piece" refers to a metal current collector used in the manufacture of an electrode, which is a space where an insulating layer is formed, and may be a metal current collector punched to have a predetermined width and length. For example, the metal test piece may be made of aluminum, copper, or an aluminum alloy.

[0034] In the present invention, the term "overlay region" refers to a region of an electrode where an insulating layer is formed. More specifically, the insulating layer covers from at least a portion of the uncoated portion of the electrode on which a composite layer is formed to at least a portion of the composite layer, and the region of the composite layer on which the insulating layer is formed can be referred to as the overlay region.

[0035] The present invention will now be described in more detail.

[0036] <Method of manufacturing secondary battery electrodes> FIG. 2 is a flowchart showing a method for manufacturing an electrode for a secondary battery according to the present invention.

[0037] Referring to FIG. 2, in one embodiment, a method for manufacturing an electrode for a secondary battery according to the present invention includes:

[0038] Step S10 of applying an electrode slurry containing an electrode active material, a conductive material, and a non-aqueous binder to one or both surfaces of a current collector;

[0039] Step S20 of applying an insulating composition including a water-based binder to at least a portion of the uncoated portion of the current collector so as to cover a portion of the electrode slurry applied to the current collector;

[0040] and Step S30 of drying the electrode slurry and insulating composition applied to the current collector.

[0041] The electrode slurry and the insulating composition each contain the same or the same type of non-aqueous organic solvent.

[0042] The method for manufacturing a secondary battery electrode according to the present invention has the advantage of using the same solvent for both the electrode slurry and the insulating composition, thereby solving problems such as gelation of different binders that may occur when simultaneously coating the electrode slurry and the insulating composition, thereby increasing electrode productivity. Furthermore, the insulating layer includes a water-based binder, which can provide excellent wet adhesion.

[0043] In one example, the method for manufacturing an electrode for a secondary battery according to the present invention can satisfy the following formula 1.

[0044] [Formula 1] 0≦T2-T1≦100 (seconds)

[0045] In formula 1, T1 means the time (seconds) at which the electrode slurry is discharged from the slot die coater onto the current collector in the step of applying the electrode slurry, T2 means the time (seconds) at which the insulating composition is discharged onto the current collector from the slot die coater in the step of applying the insulating composition.

[0046] For example, the above formula 1 satisfies the range of 0.001 to 100 (seconds), 50 (seconds) or less, or 0.01 to 10 (seconds).

[0047] Satisfying the above formula 1 means that the insulating composition is applied to the current collector before the electrode slurry is dried. The "electrode slurry is not dried" state refers to the state after the electrode slurry is applied but before the electrode drying process is performed. In one example, the present invention includes a simultaneous coating method in which the steps of applying the electrode slurry and applying the insulating composition are performed substantially simultaneously. This allows the present invention to dramatically increase productivity.

[0048] For example, the steps of applying the electrode slurry and applying the insulating composition are performed by a single die coater that includes two slots.

[0049] As another example, the steps of applying the electrode slurry and applying the insulating composition are performed by two separate die coaters.

[0050] On the other hand, the non-aqueous organic solvent contained in the electrode slurry and the insulating composition may be one or more selected from the group consisting of N-methyl-pyrrolidone (NMP), dimethylformamide (DMF), dimethylacetamide (DMAc), dimethyl sulfoxide (DMSO), ethylene carbonate (EC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), dimethyl carbonate (DMC), propylene carbonate (PC), dipropyl carbonate (DPC), butylene carbonate (BC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), acetonitrile, dimethoxyethane, tetrahydrofuran (THF), gamma butyrolactone, methyl alcohol, ethyl alcohol, and isopropyl alcohol.

[0051] In a specific example, the non-aqueous organic solvent may be one or more selected from the group consisting of N-methyl-pyrrolidone (NMP), dimethylformamide (DMF), dimethylacetamide (DMAc) and dimethylsulfoxide (DMSO).

[0052] For example, the non-aqueous organic solvent may be an amide-based organic solvent, and the same solvent as that used in producing the electrode slurry may be used, and the non-aqueous organic solvent may be N-methyl-pyrrolidone (NMP).

[0053] When N-methyl-pyrrolidone (NMP) is used as the solvent for the electrode slurry, the solvent for the insulating composition may also be N-methyl-pyrrolidone (NMP). In particular, using N-methyl-pyrrolidone (NMP) as the solvent for the insulating composition can prevent cracks from occurring at the boundary between the insulating layer and the electrode mixture layer in the overlay region of the electrode.

[0054] The insulating composition may further include inorganic particles, which can enhance electrical insulation and minimize shrinkage due to heat.

[0055] For example, the inorganic particles are one or more selected from the group consisting of AlOOH, Al2O3, γ-AlOOH, Al(OH)3, Mg(OH)2, Ti(OH)4, MgO, CaO, Cr2O3, MnO2, Fe2O3, Co3O4, NiO, ZrO2, BaTiO3, SnO2, CeO2, Y2O3, SiO2, silicon carbide (SiC), and boron nitride (BN).

[0056] In the insulating composition, the weight ratio of inorganic particles to aqueous binder is within the range of 1:99 to 95:5. Specifically, the weight ratio of inorganic particles to aqueous binder is within the range of 10:90 to 90:10, 40:60 to 90:10, 45:55 to 95:15, 45:55 to 90:10, or 50:50 to 90:10. By controlling the content range of inorganic particles, it is possible to simultaneously improve wet adhesion and thermal stability.

[0057] In one embodiment, the non-aqueous binder is at least one selected from the group consisting of polyvinylidene fluoride (PVDF), polyvinylidene fluoride-co-hexafluoropropene (PVDF-co-HFP), poly(ethylene oxide) (PEO), polyacrylic acid (PAA), polyimide (PI), polyamideimide (PAI), and polyimide-polyamideimide copolymer (PI-PAI).

[0058] The aqueous binder is at least one selected from the group consisting of styrene-butadiene rubber, acrylate styrene-butadiene rubber, acrylonitrile-butadiene rubber, acrylonitrile-butadiene-styrene rubber, acrylic rubber, butyl rubber, fluororubber, polytetrafluoroethylene, polyethylene, polypropylene, ethylene propylene copolymer, polyethylene oxide, polyvinylpyrrolidone, polyepichlorohydrin, polyphosphazene, polyacrylonitrile, polystyrene, ethylene propylene diene copolymer, polyvinylpyridine, chlorosulfonated polyethylene, latex, polyester resin, acrylic resin, phenol resin, epoxy resin, polyvinyl alcohol, hydroxypropyl methylcellulose, hydroxypropyl cellulose, and diacetyl cellulose.

[0059] In one embodiment, the insulating composition of the present invention includes an aqueous binder substituted with a non-aqueous solvent and inorganic particles dispersed in the aqueous binder matrix substituted with the non-aqueous solvent, for example, the weight ratio of the inorganic particles to the aqueous binder is in the range of 1:99 to 95:5, and the viscosity at 25°C is in the range of 50 cP to 50,000 cP.

[0060] For example, the non-aqueous organic solvent is N-methyl-pyrrolidone (NMP) and the aqueous binder is styrene-butadiene rubber (SBR).

[0061] In yet another embodiment, the step of drying the electrode slurry and insulating composition applied to the current collector is performed at an average temperature in the range of 50°C to 300°C.

[0062] The method for producing an electrode for a secondary battery according to the present invention will be described in detail below.

[0063] (1) Step (S10) of applying electrode slurry to one or both surfaces of a current collector The method for manufacturing an electrode for a secondary battery according to the present invention includes the step of coating an electrode slurry on one or both surfaces of a current collector.

[0064] In this regard, the current collector of the lithium secondary battery electrode according to the present invention can be one that has high conductivity without inducing chemical changes in the battery. For example, stainless steel, aluminum, nickel, titanium, calcined carbon, etc. can be used as the current collector. In the case of aluminum or stainless steel, it can also be surface-treated with carbon, nickel, titanium, silver, etc. For example, the current collector can be aluminum.

[0065] In addition, in the slurry for electrode active material, the positive electrode active material can be any positive electrode active material commonly used in positive electrodes, such as lithium manganese oxide, lithium cobalt oxide, lithium nickel oxide, lithium iron oxide, or a lithium composite oxide obtained by combining these, but is not limited thereto.

[0066] The non-aqueous binder contained in the positive electrode active material slurry may include one or more resins selected from the group consisting of polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-co-HFP), polyvinylidene fluoride, polyacrylonitrile, polymethylmethacrylate, and copolymers thereof. For example, the binder may include polyvinylidene fluoride.

[0067] The conductive material may be used to improve the performance of the positive electrode, such as electrical conductivity, and may be one or more selected from the group consisting of natural graphite, artificial graphite, carbon black, acetylene black, ketjen black, and carbon fiber. For example, the conductive material may include acetylene black.

[0068] The solvent used for the positive electrode slurry may be one or more non-aqueous organic solvents selected from the group consisting of N-methyl-pyrrolidone (NMP), dimethylformamide (DMF), dimethylacetamide (DMAc), dimethyl sulfoxide (DMSO), ethylene carbonate (EC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), dimethyl carbonate (DMC), propylene carbonate (PC), dipropyl carbonate (DPC), butylene carbonate (BC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), acetonitrile, dimethoxyethane, tetrahydrofuran (THF), gamma butyrolactone, methyl alcohol, ethyl alcohol, and isopropyl alcohol, and may be, for example, N-methyl-2-pyrrolidone (NMP).

[0069] (2) Step (S20) of applying an insulating composition to a portion of the uncoated area of ​​the current collector so as to cover a portion of the positive electrode slurry applied to the current collector. In the method for manufacturing a secondary battery electrode according to the present invention, an insulating composition including an aqueous binder substituted with a non-aqueous solvent may be applied to cover a portion of the uncoated portion of the current collector and a portion of the positive electrode slurry applied to the current collector. Specifically, the insulating composition is applied to the boundary line between the uncoated portion and the coated portion of the electrode.

[0070] Here, the positive electrode slurry may be in an undried state, which means that the slurry has not undergone a separate drying process using a drying device or equipment.

[0071] As mentioned above, the insulating composition may be co-coated onto the positive electrode slurry and the current collector.

[0072] The insulating composition may include a water-based binder. In a specific example, the water-based binder may be at least one selected from the group consisting of styrene-butadiene rubber, acrylate styrene-butadiene rubber, acrylonitrile-butadiene rubber, acrylonitrile-butadiene-styrene rubber, acrylic rubber, butyl rubber, fluororubber, polytetrafluoroethylene, polyethylene, polypropylene, ethylene propylene copolymer, polyethylene oxide, polyvinylpyrrolidone, polyepichlorohydrin, polyphosphazene, polyacrylonitrile, polystyrene, ethylene propylene diene copolymer, polyvinylpyridine, chlorosulfonated polyethylene, latex, polyester resin, acrylic resin, phenol resin, epoxy resin, polyvinyl alcohol, hydroxypropyl methylcellulose, hydroxypropyl cellulose, and diacetyl cellulose.

[0073] Conventionally, the non-aqueous binder polyvinylidene fluoride (PVDF) has been used for the positive electrode insulating layer. However, when the insulating layer is immersed in the electrolyte of a secondary battery, the wet adhesion strength decreases, and the insulating layer suffers from swelling or detachment. On the other hand, when an aqueous binder is used for the insulating layer, a dense film is formed, improving the wet adhesion strength of the insulating layer. For example, styrene-butadiene rubber (SBR) can be used as the aqueous binder. However, it is preferable to use N-methylpyrrolidone, which is the solvent used for forming the positive electrode composite layer, as the dispersion solvent when forming the insulating layer. When styrene-butadiene rubber is used as the aqueous binder, water can be used as the solvent. However, in this case, gelation of the organic binder PVDF used as the positive electrode binder may occur between the insulating composition and the positive electrode slurry during simultaneous coating of the insulating composition and the positive electrode slurry. This may cause cracks to occur at the boundary between the electrode insulating composition and the positive electrode slurry.

[0074] The insulating composition may further include inorganic particles. In a specific example, the inorganic particles may be one or more selected from the group consisting of AlOOH, Al2O3, γ-AlOOH, Al(OH)3, Mg(OH)2, Ti(OH)4, MgO, CaO, Cr2O3, MnO2, Fe2O3, Co3O4, NiO, ZrO2, BaTiO3, SnO2, CeO2, YO3, SiO2, silicon carbide (SiC), and boron nitride (BN), or may be one or more selected from the group consisting of AlOOH, Al2O3, γ-AlOOH, and Al(OH)3. For example, the inorganic particles may be AlOOH.

[0075] The inorganic particles may have an average particle size of 0.1 μm to 100 μm, 0.5 μm to 80 μm, 1 μm to 50 μm, 2 μm to 30 μm, 3 μm to 20 μm, or 5 μm to 10 μm. When the inorganic particles have a size within the above range, they can be uniformly coated on the electrode, minimizing the resistance of lithium ions and ensuring the performance of the lithium secondary battery.

[0076] In one example, the weight ratio of the inorganic particles to the aqueous binder may be in the range of 1:99 to 95:5. Specifically, the weight ratio of the inorganic particles to the aqueous binder may be in the range of 10:90 to 90:10, 40:60 to 90:10, 45:55 to 95:15, 45:55 to 65:35, or 65:35 to 85:15. If the content of the aqueous binder is too low, it may be difficult to achieve the desired insulating effect and the adhesion to the electrode may be weakened. Furthermore, if the content of the aqueous binder is too high, the insulating composition may flow in the overlay region during coating of the electrode, resulting in a decrease in the safety of the battery cell.

[0077] In addition, in the insulating composition according to the present invention, the inorganic particles and the aqueous binder may be contained in an amount of 1 to 50 parts by weight, 5 to 40 parts by weight, or 10 to 40 parts by weight relative to 100 parts by weight of the solvent.

[0078] The insulating composition may have a viscosity at 25°C of 50 cP to 50,000 cP, 100 cP to 45,000 cP, 1,000 cP to 40,000 cP, 2,000 cP to 35,000 cP, 3,000 cP to 30,000 cP, 4,000 cP to 20,000 cP, or 5,000 cP to 10,000 cP. When the viscosity is within the above ranges, the insulating composition can have an increased wet adhesion and can improve coatability, processability, and the like.

[0079] The solvent used in the insulating composition may be one or more non-aqueous organic solvents selected from the group consisting of N-methyl-pyrrolidone (NMP), dimethylformamide (DMF), dimethylacetamide (DMAc), dimethyl sulfoxide (DMSO), ethylene carbonate (EC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), dimethyl carbonate (DMC), propylene carbonate (PC), dipropyl carbonate (DPC), butylene carbonate (BC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), acetonitrile, dimethoxyethane, tetrahydrofuran (THF), gamma butyrolactone, methyl alcohol, ethyl alcohol, and isopropyl alcohol.

[0080] In a specific example, the non-aqueous organic solvent may be one or more selected from the group consisting of N-methyl-pyrrolidone (NMP), dimethylformamide (DMF), dimethylacetamide (DMAc), and dimethyl sulfoxide (DMSO), or may be one or more selected from the group consisting of N-methyl-pyrrolidone (NMP), dimethylformamide (DMF), and dimethylacetamide (DMAc).

[0081] For example, the non-aqueous organic solvent may be an amide-based organic solvent, and the same solvent as that used in preparing the positive electrode slurry may be used. The non-aqueous organic solvent may be N-methyl-pyrrolidone (NMP).

[0082] As described above, the insulating composition may use the same non-aqueous organic solvent as the positive electrode slurry. When the positive electrode slurry and the insulating composition use the same solvent, problems such as gelation of different binders and cracking during drying due to differences in boiling points can be resolved.

[0083] Meanwhile, in the step of applying the insulating composition to the current collector, the insulating composition may be applied while the positive electrode slurry is still wet, or the positive electrode slurry and the insulating composition may be applied simultaneously.

[0084] (3) Step S30: Drying the cathode slurry and insulating composition applied to the current collector The method for manufacturing a secondary battery electrode according to the present invention includes a step of drying the positive electrode slurry and insulating composition applied to a current collector. In a specific example, the step of drying the positive electrode slurry and insulating composition applied to the current collector may be performed at an average temperature of 50°C to 300°C.

[0085] The step of drying the positive electrode slurry and the insulating composition may be performed by a drying method commonly known in the art to completely dry the positive electrode slurry and the insulating composition and remove moisture. In a specific example, the drying may be performed at a temperature sufficient to volatilize all moisture, using a hot air method, a direct heating method, an induction heating method, or the like, but is not limited thereto. For example, the step of drying the insulating coating liquid may be performed using a hot air method.

[0086] In this case, the drying temperature may be within a range of 50° C. to 300° C., or may be 60 to 200° C. or 70 to 150° C. On the other hand, if the drying temperature of the insulating coating liquid is less than 50° C., the temperature is too low and it is difficult to completely dry the insulating coating liquid, and if the drying temperature exceeds 300° C., the drying temperature is too high and deformation of the electrodes or separator may occur.

[0087] A positive electrode mixture layer and an insulating layer are formed on the current collector, and the current collector is rolled to produce a positive electrode for a lithium secondary battery.

[0088] <Insulating composition for secondary battery electrodes> The present invention provides an insulating composition for a secondary battery electrode. In one embodiment, the insulating composition includes a non-aqueous organic solvent; and inorganic particles and an aqueous binder dispersed in the non-aqueous organic solvent. The weight ratio of the inorganic particles to the aqueous binder in the insulating composition is in the range of 1:99 to 95:5, and the viscosity at 25°C is in the range of 50 cP to 50,000 cP.

[0089] The insulating composition for a secondary battery electrode according to the present invention has excellent wet adhesion in an electrolyte solution and has the advantage of being able to inhibit the migration of lithium ions to the overlay region of the electrode, thereby suppressing capacity development, etc.

[0090] To this end, the present invention provides an insulating composition for electrodes in which inorganic particles and an aqueous binder are dispersed in a non-aqueous organic solvent. Generally, electrodes in secondary batteries exist in a state impregnated with an electrolyte. Conventional insulating layers exhibit reduced wet adhesion when impregnated with an electrolyte, failing to prevent lithium ion migration to the overlay region of the electrode, resulting in a problem of capacity development. In particular, lithium ions may precipitate in the overlay region of the electrode during capacity development, which can lead to a decrease in the stability of the battery cell. The present invention provides an insulating composition for electrodes in which inorganic particles and an aqueous binder are dispersed in a non-aqueous organic solvent used as a solvent for electrode slurry, thereby improving wet adhesion in the electrolyte. That is, when applied to an electrode, the insulating composition improves wet adhesion, inhibits lithium ion migration to the overlay region of the electrode, and prevents lithium ion precipitation. Therefore, when applied to an electrode of a secondary battery, the insulating composition improves the stability of the secondary battery.

[0091] In a specific example, the insulating composition for electrodes according to the present invention comprises inorganic particles and an aqueous binder dispersed in a non-aqueous organic solvent in a ratio of 1:99 to 95:5, and when such an insulating composition for electrodes is used for an insulating layer, it exhibits excellent wet adhesion.

[0092] Meanwhile, the wet adhesion strength of the insulating layer can be measured by immersing a metal test piece on which an insulating layer has been formed in an electrolyte, applying ultrasonic waves, and then checking whether or not the insulating layer formed on the metal test piece has swelled or detached.

[0093] The electrolyte solution used in measuring the wet adhesive strength may contain an organic solvent and an electrolyte salt, and the electrolyte salt may be a lithium salt. The lithium salt may be any of those commonly used in non-aqueous electrolytes for lithium secondary batteries without limitation. For example, the anion of the lithium salt may be F - , Cl - , Br - , I - , NO3- , N(CN)2 - , BF4 - , ClO4 - , PF6 - , (CF3)2PF4 - , (CF3)3PF3 - , (CF3)4PF2 - , (CF3)5PF - , (CF3)6P - , CF3SO3 - , CF3CF2SO3 - , (CF3SO2)2N - , (FSO2)2N - , CF3CF2(CF3)2CO - , (CF3SO2)2CH - , (SF5)3C - , CF3(CF2)7SO3 - , CF3CO2 - , CH3CO2 - , SCN - and (CF3CF2SO2)2N - It may contain any one or two or more selected from the group consisting of:

[0094] The organic solvent contained in the electrolyte solution may be any organic solvent commonly used in electrolyte solutions for lithium secondary batteries, and may be any of ethers, esters, amides, linear carbonates, cyclic carbonates, etc., which may be used alone or in combination of two or more. Among these, representative examples include carbonate compounds such as cyclic carbonates, linear carbonates, and mixtures thereof.

[0095] In addition, the insulating composition for an electrode of a secondary battery according to the present invention is applied to a positive electrode, and the non-aqueous organic solvent may be one or more selected from the group consisting of N-methyl-pyrrolidone (NMP), dimethylformamide (DMF), dimethylacetamide (DMAc), dimethyl sulfoxide (DMSO), ethylene carbonate (EC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), dimethyl carbonate (DMC), propylene carbonate (PC), dipropyl carbonate (DPC), butylene carbonate (BC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), acetonitrile, dimethoxyethane, tetrahydrofuran (THF), gamma-butyrolactone, methyl alcohol, ethyl alcohol, and isopropyl alcohol.

[0096] In a specific example, the non-aqueous organic solvent may be one or more selected from the group consisting of N-methyl-pyrrolidone (NMP), dimethylformamide (DMF), dimethylacetamide (DMAc), and dimethyl sulfoxide (DMSO), or may be one or more selected from the group consisting of N-methyl-pyrrolidone (NMP), dimethylformamide (DMF), and dimethylacetamide (DMAc).

[0097] For example, the non-aqueous organic solvent may be an amide-based organic solvent, and the same solvent as that used in preparing the positive electrode slurry may be used. The non-aqueous organic solvent may be N-methyl-pyrrolidone (NMP).

[0098] In a specific example, when the insulating composition according to the present invention is used in a positive electrode insulating coating solution, it can be simultaneously coated and dried with the coating of the positive electrode composite layer. In this case, if the solvent of the insulating composition is the same as the solvent of the positive electrode slurry, differences in drying speed can be reduced, and cracks that occur at the interface between the insulating coating and the positive electrode composite layer can be prevented. In particular, the NMP solvent can be used as a substitution solvent, and the aqueous binder can be present as a binder substituted with NMP.

[0099] The aqueous binder may be one or more selected from the group consisting of styrene-butadiene rubber, acrylate styrene-butadiene rubber, acrylonitrile-butadiene rubber, acrylonitrile-butadiene-styrene rubber, acrylic rubber, butyl rubber, fluororubber, polytetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene copolymer, polyethylene oxide, polyvinylpyrrolidone, polyepichlorohydrin, polyphosphazene, polyacrylonitrile, polystyrene, ethylene-propylene-diene copolymer, polyvinylpyridine, chlorosulfonated polyethylene, latex, polyester resin, acrylic resin, phenolic resin, epoxy resin, polyvinyl alcohol, hydroxypropyl methylcellulose, hydroxypropyl cellulose, and diacetyl cellulose. Specifically, the aqueous binder may be one or more selected from the group consisting of styrene-butadiene rubber, acrylate styrene-butadiene rubber, acrylonitrile-butadiene rubber, and acrylonitrile-butadiene-styrene rubber. For example, the aqueous binder may be styrene-butadiene rubber.

[0100] Furthermore, the insulating composition may contain inorganic particles, which may improve the safety of the battery and the strength of the insulating layer. The content of the inorganic particles may be appropriately adjusted taking into consideration the viscosity, thermal resistance, insulating properties, filling effect, dispersibility, or stability of the insulating composition. Generally, the larger the size of the inorganic particles, the higher the viscosity of the composition containing them and the greater the likelihood of sedimentation in the insulating composition. Furthermore, the smaller the size of the inorganic particles, the higher the thermal resistance tends to be. Therefore, inorganic particles of appropriate types and sizes may be selected taking these factors into consideration, and two or more types of inorganic particles may be used together as needed.

[0101] In a specific example, the inorganic particles may be one or more selected from the group consisting of AlOOH, Al2O3, γ-AlOOH, Al(OH)3, Mg(OH)2, Ti(OH)4, MgO, CaO, Cr2O3, MnO2, Fe2O3, Co3O4, NiO, ZrO2, BaTiO3, SnO2, CeO2, YO3, SiO2, silicon carbide (SiC), and boron nitride (BN), or may be one or more selected from the group consisting of AlOOH, Al2O3, γ-AlOOH, and Al(OH)3. For example, the inorganic particles may be AlOOH.

[0102] The weight ratio of the inorganic particles to the aqueous binder may be within the range of 1:99 to 95:5, or 10:90 to 70:30, 20:80 to 60:40, or 40:60 to 60:40. For example, the weight ratio of the inorganic particles to the aqueous binder in the insulating composition may be 50:50. On the other hand, if the content of the aqueous binder is too low, the insulating effect desired in the present invention is not achieved and the adhesion to the electrode is weakened. Furthermore, if the content of the aqueous binder is too high, the insulating composition may flow in the overlay region during coating of the electrode, resulting in a decrease in the safety of the battery cell.

[0103] The inorganic particles may have an average particle size of 0.01 μm to 100 μm, 0.5 μm to 80 μm, 1 μm to 50 μm, 2 μm to 30 μm, 3 μm to 20 μm, or 5 μm to 10 μm. When the inorganic particles have a size within the above range, they can be uniformly coated on the electrode, minimizing the resistance of lithium ions and ensuring the performance of the lithium secondary battery.

[0104] In another example, the insulating composition may include first and second inorganic particles with different particle size balances, resulting in a bimodal particle size distribution. This means that the inorganic particles are a mixture of small and large particles, and the spaces between the large first inorganic particles can be filled with the small second inorganic particles, allowing for an appropriate amount of inorganic particle dispersion. However, this is not limited to this.

[0105] Meanwhile, in the insulating composition for electrodes according to the present invention, the inorganic particles and SBR may be contained in an amount of 1 to 50 parts by weight, 5 to 40 parts by weight, or 10 to 40 parts by weight relative to 100 parts by weight of the NMP solvent.

[0106] The insulating composition may have a viscosity at 25°C of 50 cP to 50,000 cP, 100 cP to 45,000 cP, 1,000 cP to 40,000 cP, 2,000 cP to 35,000 cP, 3,000 cP to 30,000 cP, 4,000 cP to 20,000 cP, or 5,000 cP to 10,000 cP. If the viscosity is within the above ranges, the adhesive strength with the electrode mixture layer can be improved, and coating properties, processability, etc. can be improved.

[0107] The present invention will be described in more detail below with reference to examples and experimental examples.

[0108] However, the following examples and experimental examples are merely illustrative of the present invention, and the content of the present invention is not limited to the following examples and experimental examples.

[0109] Example 1 To 100g of styrene-butadiene rubber (hereinafter referred to as SBR, Zeon's BM451B product) binder dispersed in water at a 60:40 ratio (parts by weight), 500g of N-methyl-2-pyrrolidone (NMP) solvent was added and stirred. The stirred mixture was then heated at 100-120°C for 2 hours to completely evaporate the water, producing an NMP-substituted SBR binder. The NMP-substituted SBR binder and inorganic particles were then mixed and stirred in a 50:50 weight ratio to produce an insulating composition. The viscosity of the resulting insulating composition was 5,000 cP.

[0110] <Examples 2 to 4, Comparative Examples 1 to 3> An insulating composition was obtained in the same manner as in Example 1, except that the contents of the inorganic particles and binder were changed during the preparation of the insulating composition.

[0111] The specific compositions of Examples 1 to 4 and Comparative Examples 1 to 3 are shown in Table 1 below.

[0112] [Table 1]

[0113] <Experimental Example 1. Simultaneous coating of positive electrode slurry and insulating composition> LiNi as the positive electrode active material 0.8 Co 0.1 Mn 0.1 96 parts by weight of O2, 2 parts by weight of PVDF as a binder, and 2 parts by weight of carbon black as a conductive material were weighed and mixed in N-methylpyrrolidone (NMP) solvent to prepare a positive electrode slurry.

[0114] The positive electrode slurry and the insulating composition prepared in Example 1 or Comparative Example 1 were simultaneously applied to a current collector using a double slot die coater. Then, each electrode sample was dried at an average temperature of 60°C.

[0115] The results are shown in Figures 3 and 4. Figure 3 is a photograph showing the positive electrode slurry and the insulating composition prepared in Comparative Example 1 simultaneously coated before and after drying, and Figure 4 is a photograph showing the positive electrode slurry and the insulating composition prepared in Example 1 simultaneously coated before and after drying.

[0116] As shown in Figure 3, it was confirmed that the insulating composition of Comparative Example 1 gelled due to phase separation with the binder of the positive electrode slurry in the overlay region of the positive electrode composite layer, while Figure 4 shows that the insulating composition of Example 1 did not show any phase separation with the binder of the positive electrode slurry.

[0117] <Experimental Example 2. Measurement of wet adhesive strength of insulating layer> In order to evaluate the adhesive strength of the insulating layer according to the present invention, the following experiment was carried out.

[0118] Metal test piece with an insulating layer The insulating compositions produced in Examples 1 to 4 and Comparative Examples 2 and 3 were coated on aluminum metal foil and dried to prepare metal test pieces with an insulating layer of approximately 10 μm in thickness. The metal test pieces with the insulating layer formed thereon were punched out to a size of 2 cm × 2 cm using a punching machine for adhesive strength measurement.

[0119] Ultrasonic wave application 200 g of an electrolytic solution (EC / EMC = 3 / 7 (vol.%)) was placed in a 250 ml beaker, and the metal test piece with the insulating layer formed thereon was impregnated with the electrolytic solution. The metal test piece was fixed in a jig to control its movement.

[0120] Furthermore, ultrasonic waves were applied to the electrolyte solution in which the metal test pieces were impregnated using an ultrasonic disperser (BANDELIN, 4200) under the following ultrasonic application conditions. - Frequency: 20kHz - Tip diameter: 13mm (TS-113) -Amplitude: 100% (When using a 13mm tip, the peak-to-peak distance is 132μm)

[0121] The results are shown in Table 2 below and in Figure 5.

[0122] [Table 2]

[0123] Figure 5 shows the results of measuring the wet adhesion strength of the insulating layers of Examples 1 and 4 and Comparative Examples 2 and 3. Referring to Table 2 and Figure 5, the electrode specimen of Example 1 did not experience swelling or detachment of the insulating layer. However, in the case of Example 1, as the temperature of the electrolyte increased due to the application of ultrasound, the boiling point of EMC was 107.5°C, and the solvent evaporated, changing the measurement environment, and the measurement was stopped when it reached 109°C.

[0124] In addition, in the cases of Examples 2 and 3, although not shown in the photographs, no swelling or detachment occurred in the insulating layer of the electrode specimen, similar to Example 1. However, the boiling point of EMC is 107.5°C, and the solvent evaporated, changing the measurement environment, and the measurement was stopped when it reached 109°C.

[0125] In Example 4, no swelling or detachment of the electrode specimen occurred within 15 minutes of applying ultrasonic waves to the electrolyte. However, although not shown in the figure, as the temperature of the electrolyte increased due to the continued application of ultrasonic waves and reached 108°C, swelling and detachment of the electrode specimen occurred.

[0126] In the case of Comparative Examples 2 and 3, swelling and detachment occurred in the electrode test piece 5 minutes after ultrasonic waves were applied to the electrolyte solution.

[0127] Through this, it was confirmed that the insulating layer of the example had superior wet adhesion strength compared to the insulating layers of comparative examples 2 and 3.

[0128] <Experimental Example 3. Evaluation of battery cell capacity development> To evaluate the performance of the positive electrode including the insulating layer according to the present invention, a half cell was prepared and then the capacity development was evaluated.

[0129] Half-cell fabrication LiNi as the positive electrode active material 0.8 Co 0.1 Mn 0.1 A positive electrode slurry was prepared by weighing 96 parts by weight of O2, 2 parts by weight of PVDF as a binder, and 2 parts by weight of carbon black as a conductive material in an N-methylpyrrolidone (NMP) solvent. The composite layer slurry was applied to aluminum foil, dried, and then rolled to prepare a positive electrode having a positive electrode composite layer (average thickness: 130 μm).

[0130] The positive electrode was then dip-coated with the insulating coating solution obtained in Examples 1 to 3 and dried in a convection oven (130°C) to form an insulating layer with a thickness of 10 μm on the positive electrode. A coin-shaped half cell was manufactured using lithium foil as the negative electrode and an electrolyte containing 1 M LiPF6 in a solvent of EC:DMC:DEC = 1:2:1.

[0131] [Table 3]

[0132] Discharge capacity measurement The discharge characteristics of the batteries of Examples 5 to 7 were evaluated under the following conditions: The discharge characteristics were measured at room temperature (25°C) and at a high temperature (45°C). - Discharge: 0.1C, 0.33C, 0.5C, 1.0C, 2.5V cutoff On the other hand, in order to compare whether or not each battery exhibited capacity, a battery cell including an electrode on which no insulating layer was formed was used as Comparative Example 4. The results are shown in Table 4 and FIG. 6, and Table 5 and FIG. 7.

[0133] [Table 4]

[0134] [Table 5]

[0135] Referring to Tables 4 and 5 and Figures 6 and 7, it was confirmed that in the case of Example 7, a portion of the capacity was developed during 0.1 C discharge at high temperature (45°C), but the batteries of Examples 5 and 6 showed almost no capacity development during room temperature discharge (25°C).

[0136] These results suggest that the insulating layer has excellent wet adhesion in the electrolyte, preventing the migration of lithium ions in the overlay region of the electrode and suppressing the development of capacity during discharge. As a result, the lithium secondary battery according to the present invention is expected to be able to suppress capacity degradation due to increased cycles and improve safety.

[0137] Although the present invention has been described above with reference to preferred embodiments, it will be understood that a person skilled in the art or with ordinary knowledge in the art can make various modifications and changes to the present invention without departing from the spirit and technical scope of the present invention as set forth in the claims below.

[0138] Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification, but should be defined by the claims.

Claims

1. applying an electrode slurry containing an electrode active material, a conductive material, and a non-aqueous binder to one or both surfaces of a current collector; applying an insulating composition including an aqueous binder substituted with a non-aqueous organic solvent to cover a portion of the uncoated portion of the current collector and a portion of the electrode slurry applied to the current collector; and drying the electrode slurry and insulating composition applied to the current collector. The electrode slurry and the insulating composition each contain the same or the same type of non-aqueous organic solvent.

2. The steps of applying the electrode slurry and applying the insulating composition satisfy the following formula 1: [Formula 1] 0≦T2-T1≦100 (seconds) In formula 1, T1 means the time (seconds) at which the electrode slurry is discharged onto the current collector from the slot die coater in the step of applying the electrode slurry; 2. The method of claim 1, wherein T2 represents a time (seconds) at which the insulating composition is discharged onto the current collector from a slot die coater during the coating of the insulating composition.

3. The method of claim 1 , wherein the step of applying the insulating composition is performed while the electrode slurry applied to the current collector is not dried.

4. 2. The method for producing an electrode for a secondary battery according to claim 1, wherein the non-aqueous organic solvent is at least one selected from the group consisting of N-methyl-pyrrolidone (NMP), dimethylformamide (DMF), dimethylacetamide (DMAc), dimethyl sulfoxide (DMSO), ethylene carbonate (EC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), dimethyl carbonate (DMC), propylene carbonate (PC), dipropyl carbonate (DPC), butylene carbonate (BC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), acetonitrile, dimethoxyethane, tetrahydrofuran (THF), gamma butyrolactone, methyl alcohol, ethyl alcohol, and isopropyl alcohol.

5. The method for manufacturing an electrode for a secondary battery according to claim 1 , wherein the insulating composition further contains inorganic particles.

6. The inorganic particles include AlOOH, Al ２ O ３ , γ-AlOOH, Al(OH) ３ , Mg(OH) ２ , Ti(OH) ４ , MgO, CaO, Cr ２ O ３ , MnO ２ , Fe ２ O ３ , Co ３ O ４ , NiO, ZrO ２ , BaTiO ３ , SnO ２ , CeO ２ , Y ２ O ３ , SiO ２ 6. The method for producing an electrode for a secondary battery according to claim 5, wherein the material is at least one selected from the group consisting of silicon carbide (SiC) and boron nitride (BN).

7. 6. The method for producing an electrode for a secondary battery according to claim 5, wherein the weight ratio of the inorganic particles to the aqueous binder in the insulating composition is in the range of 1:99 to 95:

5.

8. 2. The method for producing an electrode for a secondary battery according to claim 1, wherein the non-aqueous binder is at least one selected from the group consisting of polyvinylidene fluoride (PVDF), polyvinylidene fluoride-co-hexafluoropropene (PVDF-co-HFP)), poly(ethylene oxide) (PEO), polyacrylic acid (PAA), polyimide (PI), polyamideimide (PAI), and polyimide-polyamideimide copolymer (PI-PAI).

9. 2. The method for producing an electrode for a secondary battery according to claim 1, wherein the aqueous binder is at least one selected from the group consisting of styrene-butadiene rubber, acrylate styrene-butadiene rubber, acrylonitrile-butadiene rubber, acrylonitrile-butadiene-styrene rubber, acrylic rubber, butyl rubber, fluororubber, polytetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene copolymer, polyethylene oxide, polyvinylpyrrolidone, polyepichlorohydrin, polyphosphazene, polyacrylonitrile, polystyrene, ethylene-propylene-diene copolymer, polyvinylpyridine, chlorosulfonated polyethylene, latex, polyester resin, acrylic resin, phenolic resin, epoxy resin, polyvinyl alcohol, hydroxypropyl methylcellulose, hydroxypropyl cellulose, and diacetyl cellulose.

10. The insulating composition is an aqueous binder substituted with a non-aqueous organic solvent; and inorganic particles dispersed within a matrix of the aqueous binder substituted with the non-aqueous organic solvent, the weight ratio of the inorganic particles to the aqueous binder is in the range of 1:99 to 95:5; 2. The method for producing an electrode for a secondary battery according to claim 1, wherein the viscosity of the insulating composition at 25° C. is in the range of 50 cP to 50,000 cP.

11. the non-aqueous organic solvent is N-methyl-pyrrolidone (NMP); The method for manufacturing an electrode for a secondary battery according to claim 1 , wherein the water-based binder is styrene-butadiene rubber (SBR).

12. 10. The method of claim 1, wherein the electrode slurry and the insulating composition applied to the current collector are dried at an average temperature of 50 to 300°C.

13. The method of claim 1 , wherein the steps of applying the electrode slurry and applying the insulating composition are performed by a single die coater including two slots.

14. The method of claim 1 , wherein the steps of applying the electrode slurry and applying the insulating composition are performed using two separate die coaters.

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