Primer solution for manufacturing electrode, method for manufacturing electrode for secondary battery, and electrode for secondary battery

Abstract

The present disclosure relates to a primer solution for manufacturing an electrode, comprising: a binder; and an antifoaming agent, wherein the content of the antifoaming agent is 0.00001 wt% to 3.2 wt% with respect to the total weight of the primer solution for manufacturing an electrode.

Description

Primer solution for electrode manufacturing, method for manufacturing electrode for secondary battery, and electrode for secondary battery

[0001] Embodiments of the present disclosure relate to a primer solution for manufacturing an electrode, a method for manufacturing an electrode for a secondary battery, and an electrode for a secondary battery.

[0002] With the advancement of the electronics, communications, and aerospace industries, demand for lithium secondary batteries as an energy source is rapidly increasing. In particular, with the growing emphasis on global environmentally friendly policies, the electric vehicle market is experiencing rapid growth, and research and development on lithium secondary batteries is actively underway both domestically and internationally.

[0003] A lithium secondary battery includes a cathode, an anode, and a separator interposed therebetween, and the cathode and anode each contain an active material into which lithium ions can be inserted and extracted.

[0004] When manufacturing an electrode for a lithium secondary battery, a primer may be coated on the surface of the current collector to increase the adhesion between the current collector and the electrode active material.

[0005] Embodiments of the present disclosure can provide a primer solution for manufacturing an electrode, a method for manufacturing an electrode for a secondary battery, and an electrode for a secondary battery, which can maintain excellent coating quality while improving fairness.

[0006] A secondary battery including an electrode for a secondary battery according to an embodiment of the present disclosure can be widely applied in green technology fields such as electric vehicles, battery charging stations, and solar and wind power generation using batteries.

[0007] A primer solution for electrode manufacturing according to an embodiment of the present disclosure includes a binder and a defoaming agent, and the content of the defoaming agent is 0.00001 wt% to 3.2 wt% based on the total weight of the primer solution for electrode manufacturing.

[0008] In one embodiment, the content of the defoaming agent may be 0.0005 wt% to 3.0 wt% based on the total weight of the primer solution for electrode manufacturing.

[0009] In one embodiment, the binder may include at least one selected from the group consisting of an aqueous binder and a non-aqueous binder.

[0010] In one embodiment, the binder may include at least one selected from the group consisting of a styrene-butadiene rubber (SBR)-based binder, carboxymethyl cellulose (CMC), a polyacrylic acid-based binder, a poly(3,4-ethylenedioxythiophene, PEDOT)-based binder, polyvinylidenefluoride (PVDF), vinylidene fluoride-co-hexafluoropropylene copolymer (Poly(vinylidene fluoride-co-hexafluoropropylene)), polyacrylonitrile, polymethylmethacrylate, acrylonitrile butadiene rubber (NBR), and polybutadiene rubber (BR).

[0011] In one embodiment, the defoaming agent may include at least one selected from the group consisting of a silicone-based defoaming agent, a metal soap-based defoaming agent, an amide-based defoaming agent, a polyether-based defoaming agent, a polyester-based defoaming agent, a polyglycol-based defoaming agent, and an alcohol-based defoaming agent.

[0012] In one embodiment, the primer solution may further comprise a thickener.

[0013] A method for manufacturing an electrode for a secondary battery according to an embodiment of the present disclosure includes the step of applying a first composition including a binder and an antifoaming agent and a second composition including an electrode active material onto at least one surface of an electrode current collector; wherein the first composition includes the antifoaming agent in an amount of 0.00001 wt% to 3.2 wt% based on the total weight of the first composition.

[0014] In one embodiment, the binder may include at least one selected from the group consisting of a styrene-butadiene rubber (SBR)-based binder, carboxymethyl cellulose (CMC), a polyacrylic acid-based binder, a poly(3,4-ethylenedioxythiophene, PEDOT)-based binder, polyvinylidenefluoride (PVDF), vinylidene fluoride-co-hexafluoropropylene copolymer (Poly(vinylidene fluoride-co-hexafluoropropylene)), polyacrylonitrile, polymethylmethacrylate, acrylonitrile butadiene rubber (NBR), and polybutadiene rubber (BR).

[0015] In one embodiment, the defoaming agent may include at least one selected from the group consisting of a silicone-based defoaming agent, a metal soap-based defoaming agent, an amide-based defoaming agent, a polyether-based defoaming agent, a polyester-based defoaming agent, a polyglycol-based defoaming agent, and an alcohol-based defoaming agent.

[0016] In one embodiment, the second composition may be applied onto the first composition applied onto the electrode current collector.

[0017] In one embodiment, the electrode active material may include a lithium metal compound.

[0018] In one embodiment, the electrode active material may include at least one selected from the group consisting of silicon-based materials and carbon-based materials.

[0019] In one embodiment, the second composition may further comprise a binder.

[0020] In one embodiment, the method for manufacturing an electrode for a secondary battery may further include a step of drying the first composition and the second composition applied on at least one surface of the electrode current collector.

[0021] An electrode for a secondary battery according to an embodiment of the present disclosure includes: an electrode current collector; and an electrode mixture layer formed on at least one surface of the electrode current collector; wherein the electrode mixture layer may include an antifoaming agent in a first region defined as a region within a thickness of 10 μm from one surface of the electrode current collector, in an amount of 0.00001 wt% to 10 wt% based on the total weight of the electrode mixture layer in the first region.

[0022] In one embodiment, the first region may further comprise a binder.

[0023] In one embodiment, the electrode composite layer may include a second region defined as a region on the first region and including an electrode active material.

[0024] In one embodiment, the antifoaming agent may be included in the first region in an amount of 0.00001 wt% to 5 wt% based on the total weight of the electrode mixture layer of the first region.

[0025] In one embodiment, the first region may be prepared from a primer solution comprising the binder and the antifoaming agent, and comprising 0.00001 wt% to 3.2 wt% of the antifoaming agent based on the total weight of the primer solution.

[0026] According to the present disclosure, a primer solution for manufacturing an electrode, a method for manufacturing an electrode for a secondary battery, and an electrode for a secondary battery can be provided, which can maintain excellent coating quality while improving fairness.

[0027] FIG. 1 is a flowchart illustrating a method for manufacturing an electrode for a secondary battery according to an embodiment of the present disclosure.

[0028] FIG. 2 is a drawing for explaining an electrode for a secondary battery according to an embodiment of the present disclosure.

[0029] FIG. 3 is an image comparing the bubble generation characteristics of primer solutions according to one embodiment and one comparative example of the present disclosure.

[0030] FIG. 4 is an image comparing the coating quality of primer solutions according to one embodiment and one comparative example of the present disclosure.

[0031] FIG. 5 is an image comparing the bubble generation characteristics according to the content of the antifoaming agent for primer solutions according to embodiments of the present disclosure.

[0032] Figure 6 is an image comparing the phase separation phenomenon according to the content of the antifoaming agent for primer solutions according to embodiments of the present disclosure.

[0033] FIG. 7 is a graph for explaining the change in adhesive strength according to the content of the antifoaming agent for primer solutions according to embodiments of the present disclosure.

[0034] The structural or functional descriptions of the embodiments disclosed in this specification or application are merely illustrative for the purpose of explaining embodiments according to the technical idea of ​​the present invention, and the embodiments according to the technical idea of ​​the present invention may be implemented in various forms other than the embodiments disclosed in this specification or application, and the technical idea of ​​the present invention is not construed as being limited to the embodiments described in this specification or application.

[0035] primer solution

[0036] In one aspect of the present disclosure, a primer solution for electrode production is provided, which comprises a binder and a defoaming agent, wherein the content of the defoaming agent is 0.00001 wt% to 3.2 wt% based on the total weight of the primer solution for electrode production.

[0037] A primer solution according to one embodiment of the present disclosure may be a primer solution used for electrode manufacturing. The primer solution may be coated on an electrode current collector to improve adhesion between the electrode current collector and an electrode active material layer containing an electrode active material. In an embodiment, the electrode may be a positive electrode or a negative electrode.

[0038] The primer solution contains a binder. The binder may be a substance capable of improving the adhesion between the electrode active material and the electrode current collector or between electrode active materials.

[0039] In an embodiment, the binder may include at least one selected from the group consisting of an aqueous binder and a non-aqueous binder. For example, if the solvent of the primer solution is an aqueous solvent, an aqueous binder may be used as the binder. If the solvent of the primer solution is a non-aqueous solvent, a non-aqueous binder may be used as the binder.

[0040] For example, the binder may include one or more selected from the group consisting of a styrene-butadiene rubber (SBR) binder, carboxymethyl cellulose (CMC), a polyacrylic acid binder, a poly(3,4-ethylenedioxythiophene, PEDOT) binder, polyvinylidenefluoride (PVDF), vinylidene fluoride-co-hexafluoropropylene copolymer (Poly(vinylidene fluoride-co-hexafluoropropylene), polyacrylonitrile, polymethylmethacrylate, acrylonitrile butadiene rubber (NBR), and polybutadiene rubber (BR), but is not limited to a specific example.

[0041] The primer solution includes an antifoaming agent. The antifoaming agent may be a substance that suppresses the generation of bubbles or air bubbles within the primer solution. The antifoaming agent may include, for example, one or more selected from the group consisting of a silicone-based antifoaming agent, a metal soap-based antifoaming agent, an amide-based antifoaming agent, a polyether-based antifoaming agent, a polyester-based antifoaming agent, a polyglycol-based antifoaming agent, and an alcohol-based antifoaming agent. In an embodiment, the antifoaming agent may be a substance that is not completely soluble in the solvent of the primer solution. In an embodiment, at least a portion of the antifoaming agent included in the primer solution may remain as a solid even after coating and drying the primer solution. In one embodiment, the drying of the primer solution may be performed at a temperature of 100°C to 300°C, more specifically, 100°C to 250°C.

[0042] In an embodiment, the content of the antifoaming agent in the primer solution may be 5 wt% or less, more specifically 0.00001 wt% to 3.2 wt%, and even more specifically 0.0005 wt% to 3.0 wt%. By including the content of the antifoaming agent in the primer solution within the above-described range, the generation of bubbles due to the antifoaming agent can be sufficiently suppressed, while the phenomenon of reduced adhesion of the primer layer due to phase separation can be suppressed.

[0043] In an embodiment, the antifoaming agent may be provided in the form of a dispersion dispersed within a dispersion medium, and the antifoaming agent provided in the form of a dispersion may be mixed with a binder and a solvent of a primer solution to obtain a primer solution. The content of the antifoaming agent described above may refer to the content of the active ingredient excluding the dispersion medium in the antifoaming agent dispersion provided in the form of a dispersion.

[0044] In one embodiment, when the solvent of the primer solution is an aqueous solvent, the antifoaming agent may be provided in the form of a dispersion dispersed in an aqueous dispersion medium, and the antifoaming agent may have incompatibility such that it is completely insoluble in the aqueous solvent within the primer solution. In another embodiment, when the solvent of the primer solution is a non-aqueous solvent, the antifoaming agent may be provided in the form of a dispersion dispersed in a non-aqueous dispersion medium, and the antifoaming agent may have incompatibility such that it is completely insoluble in the non-aqueous solvent within the primer solution.

[0045] In one embodiment, the primer solution may optionally further include a thickener to secure advantages in the electrode manufacturing process. The thickener may be a substance that strengthens the cohesiveness of the binder, thereby improving the problem of cracking occurring on the electrode surface. For example, the thickener may include one or more selected from the group consisting of carboxymethyl cellulose, methyl cellulose, hydroxypropyl cellulose, methyl hydroxypropyl cellulose, ethyl hydroxyethyl cellulose, methyl ethyl hydroxyethyl cellulose, and cellulose gum.

[0046] In one embodiment, the primer solution may include an aqueous solvent or a non-aqueous solvent. The solvent may include, for example, one or more substances selected from the group consisting of water, pure water, deionized water, distilled water, ethanol, isopropanol, methanol, acetone, n-propanol, t-butanol, N-methyl-2-pyrrolidone (NMP), dimethylformamide, dimethylacetamide, N,N-dimethylaminopropylamine, ethylene oxide, and tetrahydrofuran.

[0047] Method for manufacturing electrodes for secondary batteries

[0048] In another aspect of the present disclosure, a method for manufacturing an electrode for a secondary battery is provided, comprising the steps of applying a first composition including a binder and a defoaming agent and a second composition including an electrode active material on at least one surface of an electrode current collector, wherein the first composition includes the defoaming agent in an amount of 0.00001 wt% to 3.2 wt% based on the total weight of the first composition.

[0049] FIG. 1 is a flowchart illustrating a method for manufacturing an electrode for a secondary battery according to an embodiment of the present disclosure. Hereinafter, the method for manufacturing an electrode for a secondary battery according to an embodiment of the present disclosure will be described with reference to FIG. 1.

[0050] Referring to Fig. 1, the first composition and the second composition can be prepared in operation S100.

[0051] The first composition comprises a binder and a defoaming agent. In an embodiment, the first composition may be the primer solution described above. The above description of the primer solution may be applied to the first composition of the method for manufacturing a secondary battery electrode according to an embodiment of the present disclosure.

[0052] The second composition may include an electrode active material. The electrode active material may be a positive electrode active material or a negative electrode active material.

[0053] In an embodiment, the positive electrode active material may be a material capable of reversibly intercalating and deintercalating lithium ions, for example, a lithium metal compound.

[0054] According to exemplary embodiments, the positive electrode active material may include a lithium-nickel metal oxide. The lithium-nickel metal oxide may further include at least one of cobalt (Co), manganese (Mn), and aluminum (Al).

[0055] In some embodiments, the positive electrode active material may include a layered structure or crystal structure represented by the following chemical formula 1.

[0056] [Chemical Formula 1]

[0057] Li x Ni a M b O 2+z

[0058] In Chemical Formula 1, 0.9≤x≤1.2, 0.6≤a≤0.99, 0.01≤b≤0.4, -0.5≤z≤0.1 may be satisfied. As described above, M may include Co, Mn, and / or Al.

[0059] The chemical structure represented by Chemical Formula 1 represents the bonding relationship included in the layered structure or crystal structure of the positive electrode active material and does not exclude other additional elements. For example, M includes Co and / or Mn, and Co and / or Mn can serve as the main active element of the positive electrode active material together with Ni. Chemical Formula 1 is provided to express the bonding relationship of the above main active elements and should be understood as a formula encompassing the introduction and substitution of additional elements.

[0060] In one embodiment, in addition to the main active element, auxiliary elements may be further included to enhance the chemical stability of the positive electrode active material or the layered structure / crystal structure. The auxiliary elements may be incorporated into the layered structure / crystal structure to form bonds, and in this case, it should be understood that they are also included within the chemical structure range represented by Chemical Formula 1.

[0061] The auxiliary element may include, for example, at least one of Na, Mg, Ca, Y, Ti, Hf, V, Nb, Ta, Cr, Mo, W, Fe, Cu, Ag, Zn, B, Al, Ga, C, Si, Sn, Sr, Ba, Ra, P, or Zr. The auxiliary element may also act as an auxiliary active element that contributes to the capacity / output activity of the positive electrode active material together with Co or Mn, for example, Al.

[0062] For example, the positive electrode active material or the lithium-nickel metal oxide may include a layered structure or crystal structure represented by the following chemical formula 1-1.

[0063] [Chemical Formula 1-1]

[0064] Li x Ni a M1 b1 M2 b2 O 2+z

[0065] In Chemical Formula 1, M1 may include Co, Mn, and / or Al. M2 may include the auxiliary elements described above. In Chemical Formula 1-1, 0.9≤x≤1.2, 0.6≤a≤0.99, 0.01≤b1+b2≤0.4, -0.5≤z≤0.1 may be satisfied.

[0066] The positive electrode active material may further include a coating element or doping element. For example, elements substantially identical to or similar to the auxiliary elements described above may be used as the coating element or doping element. For example, the above-described elements may be used singly or in combination of two or more.

[0067] The above coating element or doping element may be present on the surface of the lithium-nickel metal oxide particle, or may penetrate through the surface of the lithium-nickel metal composite oxide particle and be included in the bonding structure represented by the above chemical formula 1 or chemical formula 1-1.

[0068] The above positive electrode active material may include a nickel-cobalt-manganese (NCM) lithium oxide. In this case, an NCM lithium oxide with an increased nickel content may be used.

[0069] Ni can be provided as a transition metal associated with the output and capacity of a lithium secondary battery. Therefore, by employing a high-content (High-Ni) composition as described above in the positive electrode active material, a high-capacity positive electrode and a high-capacity lithium secondary battery can be provided.

[0070] However, as the Ni content increases, the long-term storage stability and lifespan stability of the cathode or secondary battery may relatively deteriorate, and side reactions with the electrolyte may also increase. However, according to exemplary embodiments, the inclusion of Co can maintain electrical conductivity, while improving lifespan stability and capacity retention characteristics through Mn.

[0071] The content of Ni (e.g., the mole fraction of nickel among the total moles of nickel, cobalt, and manganese) in the NCM-based lithium oxide may be 0.6 or more, 0.7 or more, or 0.8 or more. In some embodiments, the content of Ni may be 0.8 to 0.95, 0.82 to 0.95, 0.83 to 0.95, 0.84 to 0.95, 0.85 to 0.95, or 0.88 to 0.95.

[0072] In some embodiments, the positive electrode active material may include a lithium cobalt oxide-based active material, a lithium manganese oxide-based active material, a lithium nickel oxide-based active material, or a lithium iron phosphate (LFP)-based active material (e.g., LiFePO4).

[0073] In some embodiments, the positive electrode active material may include, for example, a Mn-rich active material, an LLO (Li rich layered oxide) / OLO (Over Lithiated Oxide) active material, or a Co-less active material having a chemical structure or crystal structure represented by Chemical Formula 2.

[0074] [Chemical Formula 2]

[0075] p[Li2MnO3]·(1-p)[Li q JO2]

[0076] In chemical formula 2, 0 <p<1이고, 0.9≤q≤1.2이며, J는 Mn, Ni, Co, Fe, Cr, V, Cu, Zn, Ti, Al, Mg 및 B 중 적어도 하나의 원소를 포함할 수 있다.

[0077] In an embodiment, the negative electrode active material may be a material capable of adsorbing and desorbing lithium ions, and may include, for example, at least one selected from the group consisting of silicon-based materials and carbon-based materials. Alternatively, as another example, the negative electrode active material may include lithium metal, a lithium alloy, or a tin-based material.

[0078] The carbonaceous material may include, for example, one or more selected from the group consisting of artificial graphite, natural graphite, hard carbon, soft carbon, carbon black, acetylene black, Ketjen black, Super P, and graphene.

[0079] Silicon-based materials can provide increased capacity characteristics. The silicon-containing materials include Si, SiO x (0 <x<2), 금속 도핑된 SiO x (0 <x<2), 실리콘-탄소 복합체 등을 포함할 수 있다. 상기 금속은 리튬 및 / 또는 마그네슘을 포함할 수 있으며, 금속 도핑된 SiO x (0 <x<2)는 금속 실리케이트를 포함할 수 있다.

[0080] The lithium metal may be pure lithium metal or lithium metal with a protective layer formed thereon to suppress dendrite growth, etc. In one embodiment, a lithium metal-containing layer deposited or coated on an anode current collector may be used as the anode active material layer. In one embodiment, a lithium thin film layer may also be used as the anode active material layer.

[0081] Elements included in lithium alloys include aluminum, zinc, bismuth, cadmium, antimony, silicon, lead, tin, gallium, or indium.

[0082] The second composition may include, as a solvent, at least one substance selected from the group consisting of water, pure water, deionized water, distilled water, ethanol, isopropanol, methanol, acetone, n-propanol, t-butanol, N-methyl-2-pyrrolidone (NMP), dimethylformamide, dimethylacetamide, N,N-dimethylaminopropylamine, ethylene oxide, and tetrahydrofuran.

[0083] In an embodiment, the second composition may further include a binder. In an embodiment, the binder may include at least one selected from the group consisting of an aqueous binder and a non-aqueous binder. For example, if the solvent of the second composition is an aqueous solvent, the binder may be an aqueous binder. If the solvent of the second composition is a non-aqueous solvent, the binder may be a non-aqueous binder.

[0084] For example, the binder may include one or more selected from the group consisting of a styrene-butadiene rubber (SBR) binder, carboxymethyl cellulose (CMC), a polyacrylic acid binder, a poly(3,4-ethylenedioxythiophene, PEDOT) binder, polyvinylidenefluoride (PVDF), vinylidene fluoride-co-hexafluoropropylene copolymer (Poly(vinylidene fluoride-co-hexafluoropropylene), polyacrylonitrile, polymethylmethacrylate, acrylonitrile butadiene rubber (NBR), and polybutadiene rubber (BR), but is not limited to a specific example.

[0085] In an embodiment, the second composition may optionally further include a thickener to secure advantages in the electrode manufacturing process. The thickener may be a substance that strengthens the cohesiveness of the binder, thereby improving the problem of cracking occurring on the electrode surface. For example, the thickener may include one or more selected from the group consisting of carboxymethyl cellulose, methyl cellulose, hydroxypropyl cellulose, methyl hydroxypropyl cellulose, ethyl hydroxyethyl cellulose, methyl ethyl hydroxyethyl cellulose, and cellulose gum.

[0086] In the S200 operation, the first composition and the second composition can be applied on at least one surface of the electrode current collector.

[0087] In an embodiment, the electrode current collector is not particularly limited as long as it is conductive and does not cause a chemical change in the secondary battery, and for example, copper, stainless steel, aluminum, nickel, titanium, calcined carbon, copper or stainless steel surface-treated with carbon, nickel, titanium, silver, etc., aluminum-cadmium alloy, etc. can be used. In addition, the binding force of the negative electrode active material can be strengthened by forming fine unevenness on the surface, and can be used in various forms such as a film, sheet, foil, net, porous body, foam, non-woven fabric, etc. In one embodiment, the thickness of the electrode current collector may be 6 ㎛ to 100 ㎛, but is not limited thereto.

[0088] In an embodiment, the first composition may be applied onto an electrode current collector to form a first layer including a binder and an antifoaming agent, and the second composition may be applied onto the first composition to form a second layer including an electrode active material. The application of the first composition and the second composition may be performed sequentially or simultaneously. In one embodiment, the first composition and the second composition may be applied simultaneously onto the electrode current collector using a dual coating device.

[0089] Since the first composition contains an appropriate amount of a foaming agent as described above, the generation of bubbles can be suppressed during the preparation of the first composition in operation S100 and / or the application of the first composition in operation S200, and thus the processability during electrode manufacturing can be improved.

[0090] In the S300 operation, the first composition and the second composition applied on the electrode collector can be dried.

[0091] In an embodiment, by drying the first composition and the second composition, the solvent contained in the first composition and the second composition may be evaporated, thereby forming a first layer from the first composition and forming a second layer from the second composition. In one embodiment, the drying may be performed at a temperature of, but not limited to, 100°C to 300°C, more specifically, 100°C to 250°C.

[0092] Even after drying, at least a portion of the antifoaming agent may remain in the first layer without volatilizing. As described above, since the first composition contains 3.2 wt% or less of the antifoaming agent, the first layer may maintain excellent adhesion even after drying.

[0093] Due to the presence of the first layer with excellent adhesiveness, detachment of the second layer containing the electrode current collector and electrode active material can be prevented.

[0094] After drying, in one embodiment, the boundary between the first layer and the second layer may be clearly distinguishable, but in another embodiment, the boundary between the first layer and the second layer may not be clear as a gradient is formed due to migration of the binder or the like.

[0095] Cathode for secondary batteries

[0096] In another aspect of the present disclosure, there is provided an electrode for a secondary battery, comprising: an electrode current collector; and an electrode mixture layer formed on at least one surface of the electrode current collector; wherein the electrode mixture layer comprises, within a first region defined as a region within a thickness of 10 μm from one surface of the electrode current collector, an antifoaming agent in an amount of 0.00001 wt% to 10 wt% based on the total weight of the electrode mixture layer in the first region.

[0097] FIG. 2 is a drawing for explaining an electrode for a secondary battery according to an embodiment of the present disclosure. Hereinafter, an electrode for a secondary battery according to an embodiment of the present disclosure will be explained with reference to FIG. 2.

[0098] Referring to FIG. 2, the electrode (100) for a secondary battery includes an electrode current collector (10) and an electrode composite layer (20).

[0099] All of the above-described contents regarding the electrode current collector can be applied to the electrode current collector (10).

[0100] The electrode composite layer (20) may include a first region (21) and a second region (22). The first region (21) may be formed on at least one surface of the electrode current collector (10) and may be defined as a region within a thickness of 10 μm from one surface of the electrode current collector (10). The second region (22) may be formed on the first region (21).

[0101] The first region (21) may include a binder and an antifoaming agent. The first region (21) may include 0.00001 wt% to 10 wt% of the antifoaming agent based on the total weight of the electrode mixture layer of the first region (21), and more specifically, 0.00001 wt% to 5 wt%, 0.00001 wt% to 3.2 wt%, or 0.0005 wt% to 3.0 wt%.

[0102] In an embodiment, the first region (21) may be manufactured from the first composition described above or the primer solution described above. That is, the first region (21) may be manufactured from a primer solution containing a binder and an antifoaming agent, and containing 0.00001 wt% to 3.2 wt% of the antifoaming agent. The first region (21) may be a region formed by applying the primer solution described above onto the electrode current collector (10) and then drying it.

[0103] In the embodiment, since the first region (21) is prepared from a primer solution containing 0.00001 wt% to 3.2 wt% of a preservative, excellent adhesion can be maintained, and as a result, the electrode (100) for a secondary battery can maintain excellent performance as detachment of the electrode active material is suppressed.

[0104] The second region (22) may include an electrode active material. The second region may be a region formed by drying the second composition described above after application.

[0105] The first region (21) may correspond to the first layer after drying of FIG. 1, and the second region (22) may correspond to the second layer after drying of FIG. 1. Accordingly, in one embodiment, the boundary between the first region (21) and the second region (22) may be clearly distinguished, but in another embodiment, the boundary between the first region (21) and the second region (22) may not be clear as a gradient is formed due to migration of a binder or the like.

[0106] secondary batteries

[0107] In addition, in another aspect of the present disclosure, a secondary battery including the electrode for a secondary battery described above can be provided.

[0108] The secondary battery may include a positive electrode for a secondary battery and a negative electrode for a secondary battery, and at least one of the positive electrode and the negative electrode may be manufactured using the primer solution described above.

[0109] In addition to the electrodes according to the present disclosure, the secondary battery may include a separator. The separator may be configured to prevent electrical short-circuiting between the positive and negative electrodes and to allow ion flow. In some embodiments, the thickness of the separator may be 10 μm to 20 μm, but the present disclosure is not limited thereto.

[0110] For example, the separator may include a porous polymer film or a porous nonwoven fabric. The porous polymer film may include a polyolefin polymer such as an ethylene polymer, a propylene polymer, an ethylene / butene copolymer, an ethylene / hexene copolymer, and an ethylene / methacrylate copolymer. The porous nonwoven fabric may include high-melting-point glass fibers, polyethylene terephthalate fibers, and the like. The separator may also include a ceramic material. For example, inorganic particles may be coated on the polymer film or dispersed within the polymer film to improve heat resistance.

[0111] The separator may have a single-layer or multi-layer structure including the above-described polymer film and / or non-woven fabric.

[0112] The cathode, anode, and separator can be manufactured into an electrode assembly by a winding, lamination, folding, or zigzag stacking process. In addition, the electrode assembly can be provided together with an electrolyte to manufacture a secondary battery according to the present disclosure. The secondary battery can be any one of a cylindrical shape using a can, a square shape, a pouch shape, and a coin shape, but is not limited thereto.

[0113] Such an electrode assembly may be housed within a case together with an electrolyte to define a lithium secondary battery. In exemplary embodiments, a non-aqueous electrolyte may be used as the electrolyte.

[0114] The electrolyte may be a non-aqueous electrolyte. The electrolyte may include a lithium salt and an organic solvent. The organic solvent may include at least one of propylene carbonate (PC), ethylene carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), ethylmethyl carbonate (EMC), methylpropyl carbonate (MPC), dipropyl carbonate (DPC), vinylene carbonate (VC), dimethyl sulfoxide, acetonitrile, dimethoxyethane, diethoxyethane, sulfolane, gamma-butyrolactone, propylene sulfide, and tetrahydrofuran.

[0115] Example

[0116] Hereinafter, embodiments of the present invention will be further described with reference to specific experimental examples. The examples and comparative examples included in the experimental examples are merely illustrative of the present invention and do not limit the scope of the appended claims. It will be apparent to those skilled in the art that various modifications and variations of the examples are possible within the scope and technical spirit of the present invention, and it is also natural that such modifications and variations fall within the scope of the appended claims.

[0117] <Example 1> - Preparation of primer solution 1

[0118] A primer solution was prepared by adding a dispersion of styrene-butadiene rubber (SBR), carboxymethyl cellulose (CMC), and an antifoaming agent containing 20 wt% of the active ingredients to distilled water.

[0119] The primer solution was prepared by changing the content of the antifoaming agent, and the specific composition of the prepared primer solution is as shown in Table 1 below. In Table 1 below, the content of the antifoaming agent refers to the content of the effective ingredient excluding the dispersion medium in the antifoaming agent dispersion provided in the form of a dispersion.

[0120] SBR(wt%)CMC(wt%)Foaming agent(wt%)Distilled water(wt%)Example 1-123.990.300.0175.70Example 1-223.950.300.0575.70Example 1-323.000.301.0075.70Example 1-421.000.303.0075.70Example 1-520.500.303.5075.70

[0121] <Example 2> - Preparation of primer solution A primer solution was prepared by adding a dispersion of styrene-butadiene rubber (SBR), carboxymethyl cellulose (CMC), and an antifoaming agent containing 30 wt% of the effective ingredients to distilled water.

[0122] The primer solution was prepared by changing the content of the antifoaming agent, and the specific composition of the prepared primer solution is as shown in Table 2 below. In Table 2 below, the content of the antifoaming agent refers to the content of the effective ingredient excluding the dispersion medium in the antifoaming agent dispersion provided in the form of a dispersion.

[0123] SBR(wt%)CMC(wt%)Foaming agent(wt%)Distilled water(wt%)Example 2-123.990.300.0175.70Example 2-223.950.300.0575.70Example 2-323.000.301.0075.70Example 2-421.000.303.0075.70Example 2-520.500.303.5075.70

[0124] <Comparative Example 1> - Preparation of Primer Solution 3 A primer solution was prepared by adding only styrene-butadiene rubber (SBR) and carboxymethyl cellulose (CMC) to distilled water. The specific composition of the prepared primer solution is as shown in Table 3 below.

[0125] SBR(wt%)CMC(wt%)Distilled water(wt%)Comparison example 124.000.3075.70

[0126] <Experimental Example 1> - Characteristics according to presence or absence of foaming agent The foaming characteristics of the primer solutions according to Experimental Example 1-2 and Comparative Example 1 are compared and shown in Figure 3.

[0127] As shown in Fig. 3, it can be confirmed that in the case of Example 1-2 in which a foaming agent was added, bubble generation in the primer solution was suppressed.

[0128] On the other hand, in the case of comparative example 1 where no preservative was added, it was confirmed that bubbles were generated in the primer solution.

[0129] That is, by adding a foaming agent to the primer solution, bubble generation can be suppressed.

[0130] In addition, the frying solution of Example 1-2 and Comparative Example 1 was coated on the entire body, and the results are shown in Fig. 4.

[0131] From Fig. 4, it was confirmed that there was almost no difference in the coating quality between Examples 1-2 and Comparative Example 1. That is, even if an antifoaming agent is additionally added to the primer solution, the coating quality of the primer solution may not deteriorate due to a decrease in compatibility.

[0132] <Experimental Example 2> - Confirmation of bubble generation characteristics according to the amount of antifoaming agent added

[0133] The bubble generation characteristics of the primer solutions according to Examples 1 and 2 were confirmed and are shown in Fig. 5.

[0134] As shown in Fig. 5, it was confirmed that bubble generation could be sufficiently suppressed even if only 0.01 wt% of the antifoaming agent was added to the primer solution based on the total weight of the primer solution.

[0135] In addition, it was confirmed that the amount of bubbles generated decreased as the content of the antifoaming agent added increased, but the difference according to the content of the antifoaming agent was not large.

[0136] <Experimental Example 3> - Confirmation of adhesion according to the amount of antifoaming agent added

[0137] The phase separation characteristics of the primer solutions according to Examples 1 and 2 were confirmed and are shown in Fig. 6.

[0138] As illustrated in Fig. 6, in the cases of Examples 1-5 and 2-5 where the content of the antifoaming agent exceeded 3.2 wt% based on the total weight of the primer solution, it was confirmed that a phase separation phenomenon occurred noticeably after coating. That is, when the content of the antifoaming agent added increases, the phase separation phenomenon may be aggravated due to the incompatibility of the antifoaming agent in not being completely dissolved in water, which is a solvent.

[0139] The occurrence of such phase separation phenomena can affect the adhesive strength of the primer solution. The adhesive strength of the primer solutions according to Examples 1 and 2 was confirmed using a 90° peel strength tester that peels the copper / aluminum foil substrate and the electrode at a constant speed, and the results are shown in Table 4 and Figure 7 below.

[0140] Antifoam content (wt%) Adhesion (N / 18nm) Comparison Example 100.661 Example 1-10.010.66 Example 1-31.000.584 Example 1-43.000.485 Example 1-53.500.271 Example 2-10.010.621 Example 2-31.000.512 Example 2-43.000.321 Example 2-53.500.102

[0141] Looking at Table 4 and Figure 7, it was confirmed that as the content of the antifoaming agent increased, the adhesive strength of the primer solution decreased. In particular, in the case of Examples 1-5 and 2-5, where the content of the antifoaming agent exceeded 3.2 wt% based on the total weight of the primer solution, the adhesive strength of the primer solution decreased rapidly.

[0142] The above description is merely an example of applying the principles of the present disclosure, and other configurations may be included without departing from the scope of the present invention.

Claims

1. Contains binders and foaming agents, The content of the above-mentioned foaming agent is: A primer solution for electrode manufacturing, the primer solution comprising 0.00001 wt% to 3.2 wt% based on the total weight of the primer solution for electrode manufacturing.

2. In paragraph 1, the content of the foaming agent is: A primer solution for electrode manufacturing, the primer solution being 0.0005 wt% to 3.0 wt% based on the total weight of the primer solution for electrode manufacturing.

3. In the first paragraph, the binder, A primer solution for electrode manufacturing comprising at least one selected from the group consisting of aqueous binders and non-aqueous binders.

4. In the first paragraph, the binder, A primer solution for electrode manufacturing, comprising at least one selected from the group consisting of a styrene-butadiene rubber (SBR) binder, carboxymethyl cellulose (CMC), a polyacrylic acid binder, a poly(3,4-ethylenedioxythiophene, PEDOT) binder, polyvinylidenefluoride (PVDF), vinylidene fluoride-co-hexafluoropropylene copolymer (Poly(vinylidene fluoride-co-hexafluoropropylene)), polyacrylonitrile, polymethylmethacrylate, acrylonitrile butadiene rubber (NBR), and polybutadiene rubber (BR).

5. In the first paragraph, the foaming agent is A primer solution for electrode manufacturing, comprising at least one selected from the group consisting of a silicone-based defoaming agent, a metal soap-based defoaming agent, an amide-based defoaming agent, a polyether-based defoaming agent, a polyester-based defoaming agent, a polyglycol-based defoaming agent, and an alcohol-based defoaming agent.

6. In paragraph 1, A primer solution for electrode manufacturing further comprising a thickener.

7. A step of applying a first composition including a binder and a defoaming agent and a second composition including an electrode active material on at least one surface of an electrode current collector; The above first composition, A method for manufacturing an electrode for a secondary battery, comprising the above-mentioned defoaming agent in an amount of 0.00001 wt% to 3.2 wt% based on the total weight of the first composition.

8. In paragraph 7, the binder, A method for manufacturing an electrode for a secondary battery, comprising at least one selected from the group consisting of a styrene-butadiene rubber (SBR) binder, carboxymethyl cellulose (CMC), a polyacrylic acid binder, a poly(3,4-ethylenedioxythiophene, PEDOT) binder, polyvinylidenefluoride (PVDF), vinylidene fluoride-co-hexafluoropropylene copolymer (Poly(vinylidene fluoride-co-hexafluoropropylene)), polyacrylonitrile, polymethylmethacrylate, acrylonitrile butadiene rubber (NBR), and polybutadiene rubber (BR).

9. In paragraph 7, the foaming agent is A method for manufacturing an electrode for a secondary battery, comprising at least one selected from the group consisting of a silicone-based defoaming agent, a metal soap-based defoaming agent, an amide-based defoaming agent, a polyether-based defoaming agent, a polyester-based defoaming agent, a polyglycol-based defoaming agent, and an alcohol-based defoaming agent.

10. In the 7th paragraph, the second composition, A method for manufacturing an electrode for a secondary battery, wherein the electrode is applied on the first composition applied on the electrode current collector.

11. In paragraph 7, the electrode active material is A method for manufacturing an electrode for a secondary battery comprising a lithium metal compound.

12. In paragraph 7, the electrode active material is A method for manufacturing an electrode for a secondary battery, comprising at least one selected from the group consisting of silicon-based materials and carbon-based materials.

13. In the 7th paragraph, the second composition, A method for manufacturing an electrode for a secondary battery further comprising a binder.

14. In paragraph 7, A method for manufacturing an electrode for a secondary battery, further comprising a step of drying the first composition and the second composition applied on at least one surface of the electrode current collector.

15. Electrode current collector; and An electrode composite layer formed on at least one surface of the electrode current collector; The above electrode composite layer is, An electrode for a secondary battery, comprising a defoaming agent in a first region defined as a region within a thickness of 10 μm from one surface of the electrode current collector, in an amount of 0.00001 wt% to 10 wt% based on the total weight of the electrode mixture layer in the first region.

16. In paragraph 15, the first region, An electrode for a secondary battery further comprising a binder.

17. In the 16th paragraph, the electrode mixture layer is An electrode for a secondary battery, defined as an area on the first area above and including a second area containing an electrode active material.

18. In paragraph 15, the foaming agent is An electrode for a secondary battery, wherein the electrode mixture layer of the first region is included in an amount of 0.00001 wt% to 5 wt% based on the total weight of the electrode mixture layer of the first region.

19. In paragraph 16, the first region, A secondary battery electrode manufactured from a primer solution comprising the binder and the antifoaming agent, and containing 0.00001 wt% to 3.2 wt% of the antifoaming agent based on the total weight of the primer solution.

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