Binder composition for secondary battery

Abstract

To provide a binder composition for a lithium ion battery and an electrode for a lithium ion battery, exhibiting excellent adhering capability and high electrochemical stability, keeping those characteristics, and contributing to the excellent battery electrochemical performance.SOLUTION: A binder composition for a lithium ion battery electrode includes a copolymer and a dispersant. The copolymer includes a structure unit (a) derived from a monomer containing a carboxylic acid group, a structure unit (b) derived from a monomer containing an amide group, and a structure unit (c) derived from a monomer containing a nitrile group, and has an improved bindability. The binder composition does not include a structure unit derived from a monomer containing an ester group.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to the field of batteries, and more particularly to binder compositions for lithium ion batteries. [Background technology]

[0002] Over the past few decades, lithium-ion batteries (LIBs) have become widely used in a variety of applications, especially in home appliances, due to their excellent energy density, long cycle life, and high discharge capacity. With the rapid market development of electric vehicles (EVs) and grid energy storage, high-performance, low-cost LIBs now offer one of the most promising options for large-scale energy storage devices.

[0003] Typically, lithium-ion battery electrodes are fabricated by casting an organic slurry onto a metal current collector. The slurry contains the electrode active material, conductive carbon, and a binder in an organic solvent. The binder is electrochemically stable and binds the electrode active material together, adhering it to the current collector to produce the electrode. Polyvinylidene fluoride (PVDF) is one of the most commonly used binders in the commercial lithium-ion battery industry. However, PVDF requires special handling because it is insoluble in water and soluble only in certain flammable and toxic organic solvents, such as N-methyl-2-pyrrolidone (NMP).

[0004] To recover NMP vapor, an NMP recovery unit must be installed in the drying process. This requires a large capital investment, which adds significant costs to the manufacturing process. The use of cheaper and more environmentally friendly solvents, such as aqueous solvents, most commonly water, is preferred in the present invention because it can eliminate the large capital costs of the recovery system.

[0005] In view of these issues, attempts have been made to replace the traditional PVDF with more environmentally friendly water-soluble binder materials or to utilize the known advantages of PVDF as a binder for electrode slurries without using organic solvents during production, which require specific recovery processes.

[0006] Existing water-based binders, such as carboxymethyl cellulose (CMC) and styrene-butadiene rubber (SBR), exhibit only limited adhesive capacity and poor cycle life. SBR, in particular, requires thickeners to adjust binder viscosity. Furthermore, SBR has high swelling and unfavorable cohesion properties, resulting in uneven dispersion, high electrode resistance, and poor performance. Furthermore, high voltages are applied to the cathode in batteries. Most rubbers, including SBR, are stable only at low anode voltages and decompose at high voltages. Therefore, their application, particularly in the cathode, is somewhat limited.

[0007] EP Patent Application Publication No. 255293B1 discloses an aqueous electrode slurry for lithium-ion-containing electrochemical cells. The slurry is composed of an electrochemically active material, a combination of at least one of PVDF and SBR, and polyacrylic acid (PAA) and CMC in an aqueous solution. The proposed invention combines PVDF with an aqueous slurry that allows for easier handling, reduced environmental pollution, and reduced costs, while maintaining the known chemical and electrochemical advantages of PVDF as a binder, such as electrochemical stability, long-life stability, and the ability to achieve higher C-rates due to reduced binder content. Despite the fact that organic solvent-free slurries can be prepared based on the proposed invention, the slurries are still composed of fluorine-containing binder materials. PVDF is highly fluorinated and, when subjected to thermal decomposition, is toxic, posing risks to human health and the environment.

[0008] In view of the above, there is a continuing need for aqueous binder compositions for lithium ion batteries that exhibit excellent adhesive ability and high electrochemical stability in the preparation of cathode slurries, and that have sustained properties that contribute to excellent battery electrochemical performance. Summary of the Invention

[0009] The aforementioned needs are met by various aspects and embodiments disclosed herein. Provided herein is a binder composition for a secondary battery electrode, comprising a copolymer and a dispersing medium, the copolymer comprising structural units (a) derived from a carboxylic acid group-containing monomer, structural units (b) derived from an amide group-containing monomer, and structural units (c) derived from a nitrile group-containing monomer, and the binder has improved binding ability. Furthermore, battery cells including cathodes fabricated using the binder compositions disclosed herein exhibit excellent electrochemical performance. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a flow chart of an embodiment showing steps for preparing a binder composition. DETAILED DESCRIPTION OF THE INVENTION

[0011] Provided herein is a binder composition for a secondary battery electrode, comprising a copolymer and a dispersing medium, wherein the copolymer comprises structural units (a) derived from a carboxylic acid group-containing monomer, structural units (b) derived from an amide group-containing monomer, and structural units (c) derived from a nitrile group-containing monomer.

[0012] The term "electrode" means either a "cathode" or an "anode."

[0013] The term "negative electrode" is used interchangeably with "cathode." Similarly, the term "negative electrode" is used interchangeably with "anode."

[0014] The terms "binder," "binder material," or "binder composition" refer to a chemical compound, mixture of compounds, or polymer that forms a colloidal solution or dispersion in a carrier medium, such as water, and is used to hold electrode materials and / or conductive agents in place and deposit them onto conductive metal parts to form an electrode. In some embodiments, the electrode does not include any conductive agents.

[0015] The term "conductive agent" refers to a material that is chemically inert and has good electrical conductivity. Therefore, conductive agents are often mixed with electrode active materials during electrode formation to improve the electrical conductivity of the electrode.

[0016] The term "polymer" refers to a macromolecular compound prepared by polymerizing monomers of the same or different types. The general term "polymer" encompasses the terms "homopolymer" as well as "copolymer."

[0017] The term "homopolymer" refers to a polymer prepared by polymerization of the same type of monomers.

[0018] The term "copolymer" refers to a polymer prepared by the polymerization of two or more different types of monomers.

[0019] As used herein, the term "unsaturated" means a moiety having one or more units of unsaturation.

[0020] The term "alkyl" or "alkyl group" refers to a group of the general formula C obtained by removing a hydrogen atom from a saturated, unbranched, or branched aliphatic hydrocarbon. n H 2n+1where n is an integer between 1 and 20, or an integer between 1 and 8. Examples of alkyl groups include, but are not limited to, (C1-C8) alkyl groups, such as methyl, ethyl, propyl, isopropyl, 2-methyl-1-propyl, 2-methyl-2-propyl, 2-methyl-1-butyl, 3-methyl-1-butyl, 2-methyl-3-butyl, 2,2-dimethyl-1-propyl, 2-methyl-1-pentyl, 3-methyl-1-pentyl, 4-methyl-1-pentyl, 2-methyl-2-pentyl, 3-methyl-2-pentyl, 4-methyl-2-pentyl, 2,2-dimethyl-1-butyl, 3,3-dimethyl-1-butyl, 2-ethyl-1-butyl, butyl, isobutyl, t-butyl, pentyl, isopentyl, neopentyl, hexyl, heptyl, and octyl. Examples of long-chain alkyl groups include nonyl and decyl groups. An alkyl group can be unsubstituted or substituted with one or more suitable substituents. Further, an alkyl group can be branched or unbranched. In some embodiments, an alkyl group contains at least 2, 3, 4, 5, 6, 7, or 8 carbon atoms.

[0021] The term "cycloalkyl" or "cycloalkyl group" refers to a saturated or unsaturated cyclic non-aromatic hydrocarbon radical having a single ring or multiple condensed rings. Examples of cycloalkyl groups include, but are not limited to, (C3-C7) cycloalkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, and cycloheptyl, and saturated cyclic and bicyclic terpenes, and (C3-C7) cycloalkenyl groups such as cyclopropenyl, cyclobutenyl, cyclopentenyl, cyclohexenyl, and cycloheptenyl, and unsaturated cyclic and bicyclic terpenes. A cycloalkyl group can be unsubstituted or substituted with one or two suitable substituents. Furthermore, a cycloalkyl group can be monocyclic or polycyclic. In some embodiments, a cycloalkyl group contains at least 5, 6, 7, 8, 9, or 10 carbon atoms.

[0022] The term "alkoxy" refers to an alkyl group, as defined above, attached to the main carbon chain through an oxygen atom. Some non-limiting examples of alkoxy groups include methoxy, ethoxy, propoxy, butoxy, etc. And, the alkoxy defined above can be substituted or unsubstituted, where the substituents can be, but are not limited to, deuterium, hydroxy, amino, halo, cyano, alkoxy, alkyl, alkenyl, alkynyl, mercapto, nitro, and the like.

[0023] The term "alkenyl" refers to an unsaturated straight-chain, branched-chain, or cyclic hydrocarbon radical containing one or more carbon-carbon double bonds. Examples of alkenyl groups include, but are not limited to, ethenyl, 1-propenyl, or 2-propenyl, which may be optionally substituted on one or more of the carbon atoms of the radical.

[0024] The term "aryl" or "aryl group" refers to an organic radical derived from a monocyclic or polycyclic aromatic hydrocarbon by removing a hydrogen atom. Non-limiting examples of aryl groups include phenyl, naphthyl, benzyl, or tolanyl groups, sexiphenylene, phenanthrenyl, anthracenyl, coronenyl, and tolanylphenyl. Aryl groups can be unsubstituted or substituted with one or more suitable substituents. Furthermore, aryl groups can be monocyclic or polycyclic. In some embodiments, aryl groups contain at least 6, 7, 8, 9, or 10 carbon atoms.

[0025] The term "aliphatic" refers to C1-C 30 Alkyl groups, C2-C 30 Alkenyl groups, C2-C 30 Alkynyl groups, C1-C 30 Alkylene group, C2-C 30 Alkenylene group, or C2-C 30 It refers to an alkynylene group. In some embodiments, the alkyl group contains at least 2, 3, 4, 5, 6, 7, or 8 carbon atoms.

[0026] The term "aromatic" refers to a group containing an aromatic hydrocarbon ring, optionally containing heteroatoms or substituents. Examples of such groups include, but are not limited to, phenyl, tolyl, biphenyl, o-terphenyl, m-terphenyl, p-terphenyl, naphthyl, anthryl, phenanthryl, pyrenyl, triphenyl, and derivatives thereof.

[0027] The term "substituted" when used to describe a compound or chemical moiety means that at least one hydrogen atom of the compound or chemical moiety has been replaced with a second chemical moiety. Examples of substituents include halogen; alkyl; heteroalkyl; alkenyl; alkynyl; aryl, heteroaryl, hydroxyl; alkoxyl; amino; nitro; thiol; thioether; imine; cyano; amido; phosphonate; phosphine; carboxyl; thiocarbonyl; sulfonyl; sulfonamido; acyl; formyl; acyloxy; alkoxycarbonyl; oxo; haloalkyl (e.g., (trifluoromethyl); carbonyl groups which may be monocyclic or fused or non-fused polycyclic; carbocyclic or heterocyclic, monocyclic or fused or non-fused polycyclic aryl (e.g., phenyl, naphthyl, pyrrolyl, indolyl, furanyl, thiophenyl, imidazolyl, oxazolyl, isoxazolyl, thiazolyl ... Zolyl, triazolyl, tetrazolyl, pyrazolyl, pyridinyl, quinolinyl, isoquinolinyl, acridinyl, pyrazinyl, pyridazinyl, pyrimidinyl, benzisodazolyl, benzothiophenyl or benzofuranyl); amino (primary, secondary or tertiary); o-lower alkyl; o-aryl, aryl; aryl-lower alkyl; -CO2CH3; -CONH2; -OCH2CONH2; -NH2; -SO2NH2; -OCHF2; -CF3; -OCF3; -NH(alkyl); -N (alkyl)2; -NH(aryl); -N(alkyl)(aryl); -N(aryl)2; -CHO; -CO(alkyl); -CO(aryl); -CO2(alkyl); and -CO2(aryl); and such moieties may also be optionally substituted with fused ring structures or bridges, such as -OCHO-. These substituents may optionally be further substituted with a substituent selected from such groups. All chemical groups disclosed herein may be substituted unless otherwise specified.

[0028] The term "halogen" or "halo" means F, Cl, Br, or I.

[0029] The term "monomer unit" means a constitutional unit contributed by a single monomer to the structure of a polymer.

[0030] The term "structural unit" means all monomer units contributed by the same monomer type in a polymer.

[0031] The term "carboxylate salt group" refers to a carboxylate salt formed when a carboxylic acid reacts with a base. In some embodiments, the proton of the carboxylic acid is replaced with a metal cation. In some embodiments, the proton of the carboxylic acid is replaced with an ammonium ion.

[0032] The term "applying" refers to the act of laying or spreading a substance on a surface.

[0033] The term "current collector" refers to any conductive substrate that is in contact with an electrode layer and can conduct current to the electrode during discharge or charging of a secondary battery. Some non-limiting examples of current collectors include a single conductive metal layer or substrate and a single conductive metal layer or substrate having a conductive coating layer thereon, such as a carbon black-based coating layer. The conductive metal layer or substrate may be in the form of a foil or a porous body having a three-dimensional network structure, and may be a polymeric material, a metallic material, or a metallized polymer. In some embodiments, the three-dimensional porous current collector is covered with a conformal carbon layer.

[0034] The term "electrode layer" refers to a layer comprising an electrochemically active material in contact with a current collector. In some embodiments, the electrode layer is made by applying a coating onto the current collector. In some embodiments, the electrode layer is located on the surface of the current collector. In other embodiments, a three-dimensional porous current collector is conformally coated with the electrode layer.

[0035] The term "room temperature" refers to a room temperature of about 18°C to about 30°C, e.g., 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, or 30°C. In some embodiments, room temperature refers to a temperature of about 20°C ± 1°C, or ± 2°C, or ± 3°C. In other embodiments, room temperature refers to a temperature of about 22°C or about 25°C.

[0036] The term "particle diameter D50" refers to the volume-based cumulative 50% size (D50), which is the particle diameter at the 50% point on a cumulative curve when the total is 100% (i.e., the diameter of the particle at 50% (median) of the particle volume). Furthermore, with respect to the cathode active material of the present invention, the particle diameter D50 refers to the volume-average particle diameter of secondary particles that may be formed by the mutual aggregation of primary particles. In the case of a cathode active material composed only of primary particles, the particle diameter D50 refers to the volume-average particle diameter of the primary particles.

[0037] The term "polydispersity index" or "PDI" refers to the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn). It is a measure of the distribution of molecular weights within a given binder composition sample.

[0038] The term "solids" refers to the amount of non-volatile material remaining after evaporation.

[0039] The term "average roughness depth" or "Rz" means the arithmetic mean value of the single roughness depths of a contiguous sampling length of the current collector.

[0040] The term "peel strength" refers to the amount of force required to separate a current collector and an electrode active material coating that are bonded together. It is a measure of the bond strength between these two materials and is usually expressed in N / cm.

[0041] The term "adhesive strength" refers to the amount of force required to separate a current collector and a binder composition coating that are adhered to each other. It is a measure of the adhesive strength between such two materials and is usually expressed in N / cm.

[0042] The term "swelling" refers to the change in volume of the binder composition after immersion in an electrolyte solution or the uptake of the electrolyte solution by electrolyte-binder interactions.

[0043] The term "C-rate" refers to the charge or discharge rate of a cell or battery, expressed in terms of its total capacity (Ah or mAh). For example, a rate of 1C means utilizing all of the stored energy in 1 hour, 0.1C means utilizing 10% of the energy in 1 hour or utilizing all of the energy in 10 hours, and 5C means utilizing all of the energy in 12 minutes.

[0044] The term "ampere-hour (Ah)" refers to the unit used to specify the capacity of a battery. For example, a battery with a capacity of 1 Ah can supply a current of 1 A for 1 hour, or 0.5 A for 2 hours, etc. Therefore, 1 Ah (ampere-hour) is equivalent to 3,600 coulombs of charge. Similarly, the term "minium ampere-hour (mAh)" also refers to the unit of capacity of a battery, which is 1 / 1000 of an ampere-hour.

[0045] The term "battery cycle life" refers to the number of complete charge / discharge cycles that a battery can undergo before its nominal capacity drops below 80% of its initial rated capacity.

[0046] The term "capacity" is a property of an electrochemical cell, such as a battery, that refers to the total amount of charge that the cell can hold. Capacity is usually expressed in units of ampere-hours. The term "specific capacity" refers to the capacity output of an electrochemical cell, such as a battery, per unit weight, usually expressed in Ah / kg or mAh / g.

[0047] In the following description, all numerical values disclosed herein are approximate, regardless of whether the word "about" or "approximately" is used in connection therewith. They may vary by 1 percent, 2 percent, 5 percent, or in some cases 10-20 percent. The lower limit R L and upper limit R UWhenever a numerical range with R = R is disclosed, any number falling within that range is specifically disclosed. Specifically, numbers in the following ranges are specifically disclosed: R = R L +k*(R U -R L ), and k is a variable ranging from 0 percent to 100 percent. Additionally, any numerical range defined by two R numbers as defined above is also specifically disclosed.

[0048] Currently, cathodes are often prepared by dispersing a cathode active material, a binder material, and a conductive agent in an organic solvent such as N-methyl-2-pyrrolidone (NMP) to form a cathode slurry, which is then coated onto a current collector and dried.

[0049] Very often, binders are considered electrochemically inactive materials, and therefore their impact on cell performance is underestimated. The purpose of the binder is to adhere the active material particles and conductive agent together and form a continuous electrical conduction path to the current collector. In addition to binding ability, the binder material should be able to facilitate electron and ion transport to reduce impedance between the current collector and electrode material, and possess sufficient elasticity to prevent electrode swelling due to volume expansion and contraction during charging and discharging.

[0050] Polyvinylidene fluoride (PVDF) is widely used as a binder material in the production of lithium-ion batteries. However, PVDF requires specific handling because it dissolves only in certain organic solvents, such as NMP, which is flammable and toxic. Furthermore, an NMP recovery device must be installed during the drying process to recover NMP vapor. This increases the energy consumption and manufacturing costs of the manufacturing process. Therefore, the search for new, environmentally friendly binder materials to replace PVDF has become essential in the development of binder materials for lithium-ion batteries.

[0051] Carboxymethyl cellulose (CMC) and styrene-butadiene rubber (SBR) are some of the most common water-based binders already used in large-scale commercial applications. However, these binders have limited binding strength and ability to prevent electrode swelling. Furthermore, high voltages are applied to the cathode in batteries. Most rubbers, including SBR, are stable only at low anode voltages and decompose at high voltages. This limits their application, particularly in the cathode.

[0052] Accordingly, the present invention provides a method for preparing an aqueous binder composition comprising a copolymer and a dispersing medium, wherein the copolymer comprises structural units (a) derived from a carboxylic acid group-containing monomer, structural units (b) derived from an amide group-containing monomer, and structural units (c) derived from a nitrile group-containing monomer. Figure 1 is a flow chart of an embodiment showing steps of a method 100 for preparing the binder composition. The binder compositions described herein have been found to exhibit improved adhesive capabilities and flexibility, while at the same time having the unexpected effect of improving the capacity and electrochemical performance of cathodes formed therefrom.

[0053] In some embodiments, the binder compositions described herein are produced via polymerization in which a monomer, polymer, or monomer-polymer complex is dispersed in an aqueous phase with the generation of free radicals by a water-soluble free radical initiator.

[0054] In some embodiments, the neutralizing solution is prepared by dissolving a neutralizing agent in water. In some embodiments, the first suspension is formed by adding the neutralizing solution to the dispersion medium in step 101. The addition of the neutralizing solution is intended to improve polymerization stability and provide a pH range in which the initiator added at a later stage can generate free radicals.

[0055] Establishing a desired operating pH range is particularly important in aqueous systems. Neutralizing agents are commonly used for pH adjustment. In some embodiments, the neutralizing agent comprises an alkaline aqueous solution. In some embodiments, the neutralizing agent may be selected from the group consisting of ammonia, sodium bicarbonate, sodium hydroxide, potassium hydroxide, lithium hydroxide, ammonium hydroxide, magnesium hydroxide, calcium hydroxide, triethylamine, dimethylethanolamine (DMEA), sodium carbonate, lithium carbonate, lithium bicarbonate, and combinations thereof.

[0056] The dispersion medium is used as a solvent for the free radical initiator, neutralizing agent, and other components. In some embodiments, the binder compositions disclosed herein are prepared by an aqueous processing method in which water is used as the dispersion medium.

[0057] In some embodiments, the dispersion medium can further comprise a hydrophilic solvent selected from the group consisting of ethanol, isopropanol, n-propanol, tert-butanol, n-butanol, dimethylacetamide (DMAc), dimethylformamide (DMF), N-methylpyrrolidone (NMP), methyl ethyl ketone (MEK), ethyl acetate (EA), butyl acetate (BA), and combinations thereof. In some embodiments, the dispersion medium is free of water, ethanol, isopropanol, n-propanol, tert-butanol, n-butanol, dimethylacetamide (DMAc), dimethylformamide (DMF), N-methylpyrrolidone (NMP), methyl ethyl ketone (MEK), ethyl acetate (EA), or butyl acetate (BA).

[0058] In some embodiments, the second suspension is formed in step 102 by adding a carboxylic acid group-containing monomer to the first suspension.

[0059] In another embodiment, the second suspension is formed by adding a carboxylic acid group-containing monomer solution to the first suspension. The carboxylic acid group-containing monomer solution can be prepared by dissolving a carboxylic acid group-containing monomer in water.

[0060] The structural unit (a) is derived from a carboxylic acid group-containing monomer. Any monomer having at least one carboxylic acid group may be used as the carboxylic acid group-containing monomer without particular limitation. In some embodiments, the carboxylic acid group-containing monomer is acrylic acid, methacrylic acid, crotonic acid, 2-butylcrotonic acid, cinnamic acid, maleic acid, maleic anhydride, fumaric acid, itaconic acid, itaconic anhydride, tetraconic acid, or a combination thereof. In certain embodiments, the carboxylic acid group-containing monomer is 2-ethylacrylic acid, isocrotonic acid, cis-2-pentenoic acid, trans-2-pentenoic acid, angelic acid, tiglic acid, 3,3-dimethylacrylic acid, 3-propylacrylic acid, trans-2-methyl-3-ethylacrylic acid, cis-2-methyl-3-ethylacrylic acid, 3-isopropylacrylic acid, trans-3-methyl-3-ethylacrylic acid, cis-3-methyl-3-ethylacrylic acid, 2-isopropylacrylic acid, trimethylacrylic acid, 2-methyl-3,3-diethylacrylic acid, 3-butylacrylic acid, 2-butylacrylic acid, 2-pentylacrylic acid, 2-methyl-2-hexenoic acid, trans-3-methyl-2-hexenoic acid, 3-methyl-3-propylacrylic acid, 2-ethyl-3-propylacrylic acid, acrylic acid, 2,3-diethylacrylic acid, 3,3-diethylacrylic acid, 3-methyl-3-hexylacrylic acid, 3-methyl-3-tert-butylacrylic acid, 2-methyl-3-pentylacrylic acid, 3-methyl-3-pentylacrylic acid, 4-methyl-2-hexenoic acid, 4-ethyl-2-hexenoic acid, 3-methyl-2-ethyl-2-hexenoic acid, 3-tert-butylacrylic acid, 2,3-dimethyl-3-ethylacrylic acid, 3,3-dimethyl-2-ethylacrylic acid, 3-methyl-3-isopropylacrylic acid, 2-methyl-3-isopropylacrylic acid, trans-2-octenoic acid, cis-2-octenoic acid, trans-2-decenoic acid, α-acetoxyacrylic acid, β-trans-allyloxyacrylic acid, α-chloro-β-E-methoxyacrylic acid, or a combination thereof.In some embodiments, the carboxylic acid group-containing monomer is methyl maleate, dimethyl maleate, phenyl maleate, bromo maleate, chloromaleic acid, dichloromaleic acid, fluoromaleic acid, difluoro maleate, nonyl hydrogen maleate, decyl hydrogen maleate, dodecyl hydrogen maleate, octadecyl hydrogen maleate, fluoroalkyl hydrogen maleate, or a combination thereof. In some embodiments, the carboxylic acid group-containing monomer is maleic anhydride, methyl maleate, dimethyl maleate, acrylic anhydride, methacrylic anhydride, methacrolein, methacryloyl chloride, methacryloyl fluoride, methacryloyl bromide, or a combination thereof.

[0061] In some embodiments, the proportion of carboxylic acid group-containing monomer is from about 40% to about 70%, from about 40% to about 68%, from about 40% to about 66%, from about 40% to about 65%, from about 40% to about 64%, from about 40% to about 63%, from about 40% to about 62%, from about 40% to about 61%, from about 40% to about 60%, by weight, based on the total weight of monomers added in preparing the binder composition. %, about 40% to about 59%, about 40% to about 58%, about 40% to about 57%, about 40% to about 56%, about 40% to about 55%, about 41% to about 55%, about 42% to about 55%, about 43% to about 55%, about 44% to about 55%, about 45% to about 55%, about 43% to about 58%, about 47% to about 53%, about 47% to about 57%, about 45% to about 58%, or about 45% to about 60%.

[0062] In some embodiments, the proportion of carboxylic acid group-containing monomers is less than 70%, less than 69%, less than 68%, less than 67%, less than 66%, less than 65%, less than 64%, less than 63%, less than 62%, less than 61%, less than 60%, less than 59%, less than 58%, less than 57%, less than 56%, less than 55%, less than 54%, less than 53%, less than 52%, less than 51%, less than 50%, less than 49%, less than 48%, less than 47%, less than 46%, less than 45%, less than 44%, less than 43%, or less than 42% by weight, based on the total weight of monomers added in preparing the binder composition. In some embodiments, the proportion of carboxylic acid group-containing monomer is greater than 40%, greater than 41%, greater than 42%, greater than 43%, greater than 44%, greater than 45%, greater than 46%, greater than 47%, greater than 48%, greater than 49%, greater than 50%, greater than 51%, greater than 52%, greater than 53%, greater than 54%, greater than 55%, greater than 56%, greater than 57%, greater than 58%, greater than 59%, greater than 60%, greater than 61%, greater than 62%, greater than 63%, greater than 64%, greater than 65%, greater than 66%, greater than 67%, or greater than 68% by weight, based on the total weight of monomers added in preparing the binder composition.

[0063] In some embodiments, each of the first and second suspensions is independently stirred for about 5 to about 45 minutes, about 5 to about 40 minutes, about 5 to about 35 minutes, about 10 to about 35 minutes, about 15 to about 35 minutes, about 20 to about 35 minutes, or about 25 to about 35 minutes. In some embodiments, each of the first and second suspensions is independently stirred for more than 5 minutes, more than 10 minutes, more than 15 minutes, more than 20 minutes, more than 25 minutes, more than 30 minutes, more than 35 minutes, or more than 40 minutes.

[0064] In some embodiments, each of the first suspension and the second suspension is independently stirred at a speed of about 10 rpm to about 600 rpm, about 10 rpm to about 550 rpm, about 10 rpm to about 500 rpm, about 10 rpm to about 450 rpm, about 10 rpm to about 400 rpm, about 10 rpm to about 350 rpm, about 10 rpm to about 300 rpm, about 10 rpm to about 250 rpm, about 10 rpm to about 200 rpm, about 10 rpm to about 180 rpm, about 10 rpm to about 160 rpm, about 10 rpm to about 140 rpm, about 10 rpm to about 120 rpm, about 10 rpm to about 100 rpm, about 20 rpm to about 100 rpm, about 30 rpm to about 100 rpm, or about 40 rpm to about 100 rpm. In some embodiments, each of the first and second suspensions is independently stirred at a speed of less than 600 rpm, less than 550 rpm, less than 500 rpm, less than 450 rpm, less than 400 rpm, less than 350 rpm, less than 300 rpm, less than 250 rpm, less than 200 rpm, less than 150 rpm, less than 100 rpm, or less than 50 rpm. In some embodiments, each of the first and second suspensions is independently stirred at a speed of more than 10 rpm, more than 50 rpm, more than 100 rpm, more than 150 rpm, more than 200 rpm, more than 250 rpm, more than 300 rpm, more than 350 rpm, more than 400 rpm, more than 450 rpm, more than 500 rpm, or more than 550 rpm.

[0065] In some embodiments, the temperature of the second suspension is about 20° C. to about 30° C., about 20° C. to about 29° C., about 20° C. to about 28° C., about 20° C. to about 27° C., about 20° C. to about 26° C., about 20° C. to about 25° C., about 21° C. to about 30° C., about 22° C. to about 30° C., about 23° C. to about 30° C., about 24° C. to about 30° C., about 25° C. to about 30° C., about 22° C. to about 26° C., or about 24° C. to about 28° C. In some embodiments, the temperature of the second suspension is less than 30° C., less than 29° C., less than 28° C., less than 27° C., less than 26° C., less than 25° C., less than 24° C., less than 23° C., less than 22° C., or less than 21° C. In some embodiments, the temperature of the second suspension is greater than 20°C, greater than 21°C, greater than 22°C, greater than 23°C, greater than 24°C, greater than 25°C, greater than 26°C, greater than 27°C, greater than 28°C, or greater than 29°C.

[0066] In some embodiments, in step 103, a third suspension is formed by adding an amide group-containing monomer to the second suspension.

[0067] In another embodiment, the third suspension is formed by adding an amide group-containing monomer solution to the second suspension. The amide group-containing monomer solution can be prepared by dissolving the amide group-containing monomer in water.

[0068] The structural unit (b) is derived from an amide group-containing monomer. Any monomer having at least one amide group can be used as the amide group-containing monomer without any particular limitation. In some embodiments, the amide group-containing monomer is selected from the group consisting of acrylamide, methacrylamide, N-methylmethacrylamide, N-ethylmethacrylamide, Nn-propylmethacrylamide, N-isopropylmethacrylamide, isopropylacrylamide, Nn-butylmethacrylamide, N-isobutylmethacrylamide, N,N-dimethylacrylamide, N,N-dimethylmethacrylamide, N,N-diethylacrylamide, N,N-diethylmethacrylamide, N-methylolmethacrylamide, N-(methoxymethyl)methacrylamide, N-(ethoxymethyl)methacrylamide, N- ... acrylamide, N-(propoxymethyl)methacrylamide, N-(butoxymethyl)methacrylamide, N,N-dimethylaminopropyl methacrylamide, N,N-dimethylaminoethyl methacrylamide, N,N-dimethylol methacrylamide, diaketone methacrylamide, diacetone acrylamide, methacryloylmorpholine, N-hydroxyl methacrylamide, N-methoxymethyl acrylamide, N-methoxymethyl methacrylamide, N,N'-methylene-bis-acrylamide (MBA), N-hydroxymethyl acrylamide, or a combination thereof.

[0069] In some embodiments, the amide group-containing monomer is about 15% to about 35%, about 15% to about 34%, about 15% to about 33%, about 15% to about 32%, about 15% to about 31%, about 15% to about 30%, about 16% to about 30%, about 17% to about 30%, about 17% to about 29%, about 17% to about 28%, about 17% to about 27%, about 18% to about 27%, about 19% to about 27%, about 20% to about 27%, about 20% to about 25%, or about 15% to about 25% by weight, based on the total weight of monomers added in preparing the binder composition.

[0070] In some embodiments, the proportion of the amide group-containing monomer is less than 34%, less than 33%, less than 32%, less than 31%, less than 30%, less than 29%, less than 28%, less than 27%, less than 26%, less than 25%, less than 24%, less than 23%, less than 22%, less than 21%, less than 20%, less than 19%, less than 18%, less than 17%, or less than 16% by weight, based on the total weight of the monomers added in preparing the binder composition. In some embodiments, the proportion of the amide group-containing monomer is greater than 15%, greater than 16%, greater than 17%, greater than 18%, greater than 19%, greater than 20%, greater than 21%, greater than 20%, greater than 23%, greater than 24%, greater than 25%, greater than 26%, greater than 27%, greater than 28%, or greater than 29% by weight, based on the total weight of the monomers added in preparing the binder composition.

[0071] In some embodiments, the third suspension is stirred for about 5 to about 60 minutes, about 5 to about 55 minutes, about 5 to about 50 minutes, about 10 to about 50 minutes, about 15 to about 50 minutes, about 20 to about 50 minutes, about 25 to about 50 minutes, about 30 to about 50 minutes, or about 35 to about 50 minutes. In some embodiments, the third suspension is stirred for less than 60 minutes, less than 55 minutes, less than 50 minutes, less than 45 minutes, less than 40 minutes, less than 35 minutes, less than 30 minutes, less than 25 minutes, less than 20 minutes, less than 15 minutes, or less than 10 minutes. In some embodiments, the third suspension is stirred for more than 5 minutes, more than 10 minutes, more than 15 minutes, more than 20 minutes, more than 25 minutes, more than 30 minutes, more than 35 minutes, more than 40 minutes, more than 45 minutes, more than 50 minutes, or more than 55 minutes.

[0072] In some embodiments, the third suspension is stirred at a speed of about 10 rpm to about 600 rpm, about 10 rpm to about 550 rpm, about 10 rpm to about 500 rpm, about 10 rpm to about 450 rpm, about 10 rpm to about 400 rpm, about 10 rpm to about 350 rpm, about 10 rpm to about 300 rpm, about 10 rpm to about 250 rpm, about 10 rpm to about 200 rpm, about 10 rpm to about 180 rpm, about 10 rpm to about 160 rpm, about 10 rpm to about 140 rpm, about 10 rpm to about 120 rpm, about 10 rpm to about 100 rpm, about 20 rpm to about 100 rpm, about 30 rpm to about 100 rpm, or about 40 rpm to about 100 rpm. In some embodiments, the third suspension is stirred at a speed of less than 600 rpm, less than 550 rpm, less than 500 rpm, less than 450 rpm, less than 400 rpm, less than 350 rpm, less than 300 rpm, less than 250 rpm, less than 200 rpm, less than 150 rpm, less than 100 rpm, or less than 50 rpm. In some embodiments, the third suspension is stirred at a speed of greater than 10 rpm, greater than 50 rpm, greater than 100 rpm, greater than 150 rpm, greater than 200 rpm, greater than 250 rpm, greater than 300 rpm, greater than 350 rpm, greater than 400 rpm, greater than 450 rpm, greater than 500 rpm, or greater than 550 rpm.

[0073] In some embodiments, the temperature of the third suspension is increased to about 30°C to about 70°C, about 32°C to about 70°C, about 34°C to about 70°C, about 36°C to about 70°C, about 38°C to about 70°C, about 40°C to about 70°C, about 42°C to about 70°C, about 44°C to about 70°C, about 46°C to about 70°C, about 48°C to about 70°C, or about 50°C to about 70°C.

[0074] In some embodiments, the temperature of the third suspension is elevated to less than 70° C., less than 68° C., less than 66° C., less than 64° C., less than 62° C., less than 60° C., less than 58° C., less than 56° C., less than 54° C., less than 52° C., less than 50° C., less than 48° C., less than 46° C., less than 44° C., less than 42° C., less than 40° C., less than 38° C., less than 36° C., or less than 34° C. In some embodiments, the temperature of the third suspension is elevated to greater than 30° C., greater than 32° C., greater than 34° C., greater than 36° C., greater than 38° C., greater than 40° C., greater than 42° C., greater than 44° C., greater than 46° C., greater than 48° C., greater than 50° C., greater than 52° C., greater than 54° C., greater than 56° C., greater than 58° C., greater than 60° C., greater than 62° C., greater than 64° C., or greater than 66° C.

[0075] In some embodiments, the fourth suspension is formed in step 104 by adding a nitrile group-containing monomer to the third suspension.

[0076] In another embodiment, the fourth suspension is formed by adding a nitrile group-containing monomer solution to the third suspension. The nitrile group-containing monomer solution can be prepared by dissolving a nitrile group-containing monomer in water.

[0077] The structural unit (c) is derived from a nitrile group-containing monomer. Any monomer having at least one nitrile group can be used as the nitrile group-containing monomer without any particular limitation. In some embodiments, the nitrile group-containing monomer includes an α,β-ethylenically unsaturated nitrile monomer. In some embodiments, the nitrile group-containing monomer is acrylonitrile, α-halogenoacrylonitrile, α-alkylacrylonitrile, or a combination thereof. In some embodiments, the nitrile group-containing monomer is α-chloroacrylonitrile, α-bromoacrylonitrile, α-fluoroacrylonitrile, methacrylonitrile, α-ethylacrylonitrile, α-isopropylacrylonitrile, α-n-hexylacrylonitrile, α-methoxyacrylonitrile, 3-methoxyacrylonitrile, 3-ethoxyacrylonitrile, α-acetoxyacrylonitrile, α-phenylacrylonitrile, α-tolylacrylonitrile, α-(methoxyphenyl)acrylonitrile, α-(chlorophenyl)acrylonitrile, α-(cyanophenyl)acrylonitrile, vinylidene cyanide, or a combination thereof.

[0078] In certain embodiments, the proportion of the nitrile group-containing monomer is about 10% to about 24%, about 10.5% to about 24%, about 11% to about 24%, about 11.5% to about 24%, about 12% to about 24%, about 12.2% to about 24%, about 12.4% to about 24%, about 12.4% to about 24%, about 12.6% to about 24%, about 12.8% to about 24%, about 13% to about 24%, about 13.2% to about 24%, about 13.4% to about 24%, about 13.6 to about 24%, about 13.8% to about 24%, about 14% to about 24%, or about 14.2% to about 24%, approximately 14.4% to approximately 24%, approximately 14.6% to approximately 24%, approximately 14.8% to approximately 24%, approximately 15% to approximately 24%, approximately 15.2% to approximately 24%, approximately 15.4% to approximately 24%, approximately 15.6% to approximately 24%, approximately 15.8% to approximately 24%, approximately 16% to approximately 24%, approximately 16.2% to approximately 24%, 16.4% to approximately 2 4%, about 16.6% to about 24%, about 16.8% to about 24%, about 17% to about 24%, about 17% to about 23.8%, about 17% to about 23.6%, about 17% to about 23.4%, about 17% to about 23.2%, about 17% to about 23%, about 16% to about 23%, about 16% to about 22%, or about 15% to about 22%.

[0079] In some embodiments, the proportion of nitrile group-containing monomers is greater than 10%, greater than 11%, greater than 12%, greater than 13%, greater than 14%, greater than 15%, greater than 16%, greater than 17%, greater than 18%, greater than 19%, greater than 20%, greater than 21%, greater than 22%, or greater than 23% by weight, based on the total weight of monomers added in preparing the binder composition. In some embodiments, the proportion of nitrile group-containing monomers is less than 24%, less than 23%, less than 22%, less than 21%, less than 20%, less than 19%, less than 18%, less than 17%, less than 16%, less than 15%, less than 14%, less than 13%, less than 12%, or less than 11% by weight, based on the total weight of monomers added in preparing the binder composition.

[0080] In certain embodiments, a combination of a carboxylic acid group-containing monomer, a nitrile group-containing monomer, and an amide group-containing monomer may be added to the first suspension to form the second suspension without forming a third or fourth suspension. In other embodiments, the carboxylic acid group-containing monomer, the nitrile group-containing monomer, the amide group-containing monomer, or a combination thereof may be added sequentially to the first suspension to form the second, third, or fourth suspension. Agitation or dispersion may be employed between these additions, which is advantageous because it can improve dispersion of the materials. When the combination of monomers is added sequentially, the formation of the third or fourth suspension may be omitted.

[0081] In some embodiments, the fourth suspension is stirred for about 5 minutes to about 30 minutes, about 5 minutes to about 28 minutes, about 5 minutes to about 26 minutes, about 5 minutes to about 24 minutes, about 5 minutes to about 22 minutes, about 5 minutes to about 20 minutes, about 5 minutes to about 18 minutes, or about 5 minutes to about 15 minutes. In some embodiments, the fourth suspension is stirred for less than 30 minutes, less than 28 minutes, less than 26 minutes, less than 24 minutes, less than 22 minutes, less than 20 minutes, less than 18 minutes, less than 16 minutes, less than 14 minutes, less than 12 minutes, less than 10 minutes, or less than 8 minutes. In some embodiments, the fourth suspension is stirred for more than 5 minutes, more than 7 minutes, more than 10 minutes, more than 12 minutes, more than 14 minutes, more than 16 minutes, more than 18 minutes, more than 20 minutes, more than 22 minutes, more than 24 minutes, more than 26 minutes, or more than 28 minutes.

[0082] In some embodiments, the fourth suspension is stirred at a speed of about 10 rpm to about 600 rpm, about 10 rpm to about 550 rpm, about 10 rpm to about 500 rpm, about 10 rpm to about 450 rpm, about 10 rpm to about 400 rpm, about 10 rpm to about 350 rpm, about 10 rpm to about 300 rpm, about 10 rpm to about 250 rpm, about 10 rpm to about 200 rpm, about 10 rpm to about 180 rpm, about 10 rpm to about 160 rpm, about 10 rpm to about 140 rpm, about 10 rpm to about 120 rpm, about 10 rpm to about 100 rpm, about 20 rpm to about 100 rpm, about 30 rpm to about 100 rpm, or about 40 rpm to about 100 rpm. In some embodiments, the fourth suspension is stirred at a speed of less than 600 rpm, less than 550 rpm, less than 500 rpm, less than 450 rpm, less than 400 rpm, less than 350 rpm, less than 300 rpm, less than 250 rpm, less than 200 rpm, less than 150 rpm, less than 100 rpm, or less than 50 rpm. In some embodiments, the fourth suspension is stirred at a speed of greater than 10 rpm, greater than 50 rpm, greater than 100 rpm, greater than 150 rpm, greater than 200 rpm, greater than 250 rpm, greater than 300 rpm, greater than 350 rpm, greater than 400 rpm, greater than 450 rpm, greater than 500 rpm, or greater than 550 rpm.

[0083] In some embodiments, the copolymer is obtained through polymerization of the composition. In some embodiments, the composition includes a carboxylate group-containing monomer, a carboxylic acid group-containing monomer, a nitrile group-containing monomer, and an amide group-containing monomer. In some embodiments, the formation of the carboxylate group-containing monomer results from neutralization of the carboxylic acid group-containing monomer with the neutralizing agent added in step 101.

[0084] In certain embodiments, the carboxylic acid group-containing monomer is an acrylate, a methacrylate, a crotonate, a 2-butylcrotonate, a cinnamate, a maleate, a maleic anhydride, a fumarate, an itaconate, an itaconate anhydride, a tetraconate, or a combination thereof. In certain embodiments, the carboxylic acid group-containing monomer is an acrylate, a methacrylate, a crotonate, a cinnamate, a maleate, a maleic anhydride, a fumarate, an itaconate, an itaconate anhydride, a tetraconate, or a combination thereof. In certain embodiments, the carboxylic acid group-containing monomer is an acrylate, a methacrylate, a cis-2-pentenoate, a trans-2-pentenoate, an angelate, a tiglicate, a 3,3-dimethylacrylate, a 3-propylacrylate, a trans-2-methyl-3-ethylacrylate, a cis-2-methyl-3-ethylacrylate, a 3-isopropylacrylate, a trans-3-methyl-3-ethylacrylate, a cis-3-methyl-3-ethylacrylate, a 2-isopropylacrylate, a trimethylacrylate, a 2-methyl-3,3-diethylacrylate, a 3-butylacrylate, a methyl ... Acrylates, 2-butylacrylate, 2-pentylacrylate, 2-methyl-2-hexenoate, trans-3-methyl-2-hexenoate, 3-methyl-3-propylacrylate, 2-ethyl-3-propylacrylate, 2,3-diethylacrylate, 3,3-diethylacrylate, 3-methyl-3-hexylacrylate, 3-methyl-3-tert-butylacrylate, 2-methyl-3-pentylacrylate, 3-methyl-3-pentylacrylate, 4-methyl-2-hexenoate, 4-ethyl-2-hexenoate, 3-methyl-2ethyl-2-hexenoate, 3-tert-butylacrylate. 2,3-dimethyl-3-ethylacrylate, 3,3-dimethyl-2-ethylacrylate, 3-methyl-3-isopropylacrylate, 2-methyl-3-isopropylacrylate, trans-2-octenoate, cis-2-octenoate, trans-2-decenoate, α-acetoxyacrylate, β-trans-allyloxyacrylate, α-chloro-β-E-methoxyacrylate, or a combination thereof.In some embodiments, the carboxylic acid salt-containing monomer is methyl maleate, dimethyl maleate, phenyl maleate, bromo maleate, chloro maleate, dichloro maleate, fluoro maleate, difluoro maleate, or a combination thereof.

[0085] In some embodiments, the carboxylate group-containing monomer is an alkali metal carboxylate group-containing monomer. Examples of alkali metals that form alkali metal carboxylate salts include lithium, sodium, and potassium. In some embodiments, the carboxylate group-containing monomer is an ammonium carboxylate group-containing monomer.

[0086] In some embodiments, the molar ratio of carboxylic acid group-containing monomer to carboxylate salt group-containing monomer in the composition is from about 0 to about 0.8, from about 0 to about 0.78, from about 0 to about 0.76, from about 0 to about 0.74, from about 0 to about 0.72, from about 0 to about 0.7, from about 0 to about 0.68, from about 0 to about 0.66, from about 0 to about 0.64, from about 0 to about 0.62, from about 0 to about 0.6, from about 0 to about 0.58, from about 0 to about 0.56, from about 0 to about 0.54, from about 0 to about 0. 0.52, about 0 to about 0.5, about 0 to about 0.48, about 0 to about 0.46, about 0 to about 0.44, about 0 to about 0.42, about 0 to about 0.4, about 0 to about 0.38, about 0 to about 0.36, about 0 to about 0.34, about 0 to about 0.32, about 0 to about 0.3, about 0.02 to about 0.3, about 0.04 to about 0.3, about 0.06 to about 0.3, about 0.08 to about 0.3, about 0.1 to about 0.3, about 0.05 to about 0.5, or about 0.05 to about 0.4.

[0087] In some embodiments, the molar ratio of carboxylic acid group-containing monomer to carboxylate salt group-containing monomer in the composition is less than 0.8, less than 0.75, less than 0.7, less than 0.65, less than 0.6, less than 0.55, less than 0.5, less than 0.45, less than 0.4, less than 0.35, less than 0.3, less than 0.25, less than 0.2, less than 0.15, less than 0.1, or less than 0.05. In some embodiments, the molar ratio of carboxylic acid group-containing monomer to carboxylate salt group-containing monomer in the composition is greater than 0, greater than 0.05, greater than 0.1, greater than 0.15, greater than 0.2, greater than 0.25, greater than 0.3, greater than 0.35, greater than 0.4, greater than 0.45, greater than 0.5, greater than 0.55, greater than 0.6, greater than 0.65, greater than 0.7, or greater than 0.75.

[0088] In some embodiments, the proportion of carboxylic acid group-containing monomers is, by mole, based on the total number of moles of monomers in the composition, from about 0% to about 30%, from about 0% to about 29%, from about 0% to about 28%, from about 0% to about 27.5%, from about 0% to about 27%, from about 0% to about 26.5%, from about 0% to about 26%, from about 0% to about 25%, from about 0% to about 24%, from about 0% to about 23%, from about 0% to about 22%, about 0% to about 21%, about 0% to about 20%, about 0% to about 19%, about 0% to about 18%, about 0% to about 17%, about 0% to about 16%, about 0% to about 15%, about 1% to about 15%, about 2% to about 15%, about 3% to about 15%, about 4% to about 15%, about 5% to about 15%, about 6% to about 15%, about 6% to about 14%, about 6% to about 13%, about 5% to about 20%, or about 5% to about 25%.

[0089] In some embodiments, the proportion of carboxylic acid group-containing monomers is less than 30%, less than 29%, less than 28%, less than 27%, less than 26%, less than 25%, less than 24%, less than 23%, less than 22%, less than 21%, less than 20%, less than 19%, less than 18%, less than 17%, less than 16%, less than 15%, less than 14%, less than 13%, less than 12%, less than 11%, less than 10%, less than 9%, less than 8%, less than 7%, less than 6%, less than 5%, less than 4%, less than 3%, or less than 2% by mole, based on the total moles of monomers in the composition. In some embodiments, the proportion of carboxylic acid group-containing monomers is greater than 0%, greater than 1%, greater than 2%, greater than 3%, greater than 4%, greater than 5%, greater than 6%, greater than 7%, greater than 8%, greater than 9%, greater than 10%, greater than 11%, greater than 12%, greater than 13%, greater than 14%, greater than 15%, greater than 16%, greater than 17%, greater than 18%, greater than 19%, greater than 20%, greater than 21%, greater than 22%, greater than 23%, greater than 24%, greater than 25%, greater than 26%, greater than 27%, or greater than 28% by mole, based on the total moles of monomers in the composition.

[0090] In some embodiments, the proportion of carboxylate group-containing monomers is, by mole, about 25% to about 45%, about 25.5% to about 45%, about 26% to about 45%, about 26.5% to about 45%, about 27% to about 45%, about 27.5% to about 45%, about 28% to about 45%, about 28.5% to about 45%, about 29% to about 45%, about 29.5% to about 45%, about 30% to about 45%, about 30% to about 44.5%, about 30% to about 44%, about 30% to about 43.5%, about 30% to about 43%, about 30% to about 42.5%, about 30% to about 42%, about 30% to about 41.5%, about 30% to about 41%, about 30% to about 40.5%, about 30% to about 40%, about 25% to about 35%, or about 35% to about 40%.

[0091] In some embodiments, the proportion of carboxylate group-containing monomers is less than 45%, 44%, 43%, 42%, 41%, 40%, 39%, 38%, 37%, 36%, 35%, 34%, 33%, 32%, 31%, 30%, 29%, 28%, 27%, or 26% by mole, based on the total moles of monomers in the composition. In some embodiments, the proportion of carboxylate group-containing monomers is greater than 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, or 39% by mole, based on the total moles of monomers in the composition.

[0092] In some embodiments, the proportion of the nitrile group-containing monomer is, by mole, about 10% to about 30%, about 11% to about 30%, about 12% to about 30%, about 13% to about 30%, about 14% to about 30%, about 15% to about 30%, about 16% to about 30%, about 17% to about 30%, about 18% to about 30%, about 19% to about 30%, about 20% to about 25%, about 26% to about 27%, about 28% to about 29%, about 30% to about 31%, about 32% to about 32%, about 33% to about 33%, about 34% to about 34%, about 35% to about 35%, about 36% to about 36%, about 37% to about 37%, about 38% to about 38%, about 39% to about 40%, about 41% to about 41%, about 42% to about 42%, about 43% to about 43%, about 44% to about 44%, about 45% to about 45%, about 46% to about 46%, about 47% to about 47%, about 48% to about 48%, about 49% to about 49%, about 50% to about 50%, about 51% to about 51%, about 52% to about 52%, about 53% to about 53%, about 54% to about 54%, about 55% to about 55%, about 56% to about 56%, about 57% to about 57%, about 58% to about 58%, about 59% to about 59%, about 60% to about 60%, about 61% to about 61%, about 62% to about 62%, about 63% to about % to about 30%, about 20% to about 29%, about 20% to about 28%, about 20% to about 27%, about 20% to about 26%, about 20% to about 25%, about 11% to about 25%, about 12% to about 25%, about 13% to about 25%, about 14% to about 25%, about 15% to about 25%, about 16% to about 27%, about 17% to about 27%, about 18% to about 27%, about 19% to about 27%, or about 10% to about 27%.

[0093] In some embodiments, the proportion of nitrile group-containing monomers is less than 30%, less than 29%, less than 28%, less than 27%, less than 26%, less than 25%, less than 24%, less than 23%, less than 22%, less than 21%, less than 20%, less than 19%, less than 18%, less than 17%, less than 16%, less than 15%, less than 14%, less than 13%, or less than 12% by mole, based on the total moles of monomers in the composition. In some embodiments, the proportion of nitrile group-containing monomers is greater than 10%, greater than 11%, greater than 12%, greater than 13%, greater than 14%, greater than 15%, greater than 16%, greater than 17%, greater than 18%, greater than 19%, greater than 20%, greater than 21%, greater than 22%, greater than 23%, greater than 24%, greater than 25%, greater than 26%, greater than 27%, or greater than 28% by mole, based on the total moles of monomers in the composition.

[0094] In some embodiments, the proportion of the amide group-containing monomer is, by mole, about 10% to about 35%, about 10% to about 34%, about 10% to about 33%, about 10% to about 32%, about 10% to about 31%, about 10% to about 30%, about 11% to about 30%, about 12% to about 30%, about 13% to about 30%, about 14% to about 30%, about 15% to about 30%, about 16% to about 30%, about 17% to about 30%, about 18% to about 30%, about 19% to about 30%, about 20% to about 30%, about 20% to about 29%, about 20% to about 28%, about 15% to about 35%, or about 20% to about 35%, based on the total number of moles of monomers in the composition.

[0095] In some embodiments, the proportion of amide group-containing monomers is less than 35%, less than 34%, less than 33%, less than 32%, less than 31%, less than 30%, less than 29%, less than 28%, less than 27%, less than 26%, less than 25%, less than 24%, less than 23%, less than 22%, less than 21%, less than 20%, less than 18%, less than 16%, less than 14%, or less than 12% by mole, based on the total moles of monomers in the composition. In some embodiments, the proportion of amide group-containing monomers is greater than 10%, greater than 11%, greater than 12%, greater than 13%, greater than 14%, greater than 15%, greater than 16%, greater than 17%, greater than 18%, greater than 19%, greater than 20%, greater than 21%, greater than 22%, greater than 23%, greater than 24%, greater than 25%, greater than 26%, greater than 27%, greater than 28%, greater than 29%, greater than 30%, greater than 32%, or greater than 34% by mole, based on the total moles of monomers in the composition.

[0096] In some embodiments, the initiator solution is prepared by dissolving an initiator in water. In some embodiments, the fifth suspension is formed in step 105 by adding the initiator solution to the fourth suspension.

[0097] In another embodiment, the fifth suspension is formed by sequentially adding portions of the initiator solution into the fourth suspension, with stirring or dispersion being employed during addition.

[0098] The polymerization that occurs in the present invention follows a radical mechanism in which an initiator acts to generate free radicals, which lead to the propagation of polymer chains. The free radicals used herein can be generated using thermal decomposition or redox reactions. The free radical initiator(s) disclosed herein are water-soluble.

[0099] The water-soluble free radical initiators thermally decompose in the aqueous phase to provide radicals capable of initiating polymerization. In some embodiments, the water-soluble initiator can be selected from the group consisting of persulfate initiators, such as ammonium persulfate, sodium persulfate, and potassium persulfate; azo initiators, such as azobis(isobutyl-amidine hydrochloride) (AIBA), 2,2′-azobis(2-methylpropionamidine) dihydrochloride, 2,2′-azobis(2-amidinopropane) dihydrochloride (AAPH), 2,2′-azobis[2-(2-imidazolin-2-yl)propane] dihydrochloride, bis[2-(4′-sulfophenyl)alkyl]-2,2′-azodiisobutyrate ammonium salts, and 2,2′-azobis(N-2′-methylpropanoyl-2-aminoalkyl-1)-sulfonic acid; and peroxide initiators, such as hydrogen peroxide, t-butyl hydroperoxide, and succinic acid peroxide, and combinations thereof.

[0100] In some embodiments, a water-soluble free radical initiator can be used in conjunction with a reducing agent to establish a redox initiator system, which allows for the generation of free radicals via an oxidation-reduction reaction at relatively low temperatures, facilitating an increased rate of polymerization.

[0101] In some embodiments, the reducing agent solution is prepared by dissolving a reducing agent in water. In some embodiments, the reducing agent can be selected from the group consisting of sodium bisulfite, sodium metabisulfite, sodium sulfite, sodium thiosulfate, thiourea dioxide, ferrous sulfate, ferrous chloride, ascorbic acid, citric acid, tartaric acid, erythorbic acid, glucose, formaldehyde sulfoxylate metal salts, burgolite FF6M, and combinations thereof.

[0102] In some embodiments, when a redox initiator system is selected as the initiator, the molar ratio of water-soluble free radical initiator to reducing agent is about 0.2 to about 10, about 0.2 to about 9, about 0.2 to about 8, about 0.2 to about 7, about 0.2 to about 6, about 0.2 to about 5, about 0.3 to about 5, about 0.4 to about 5, about 0.5 to about 5, about 0.6 to about 5, about 0.7 to about 5, about 0.8 to about 5, about 0.9 to about 5, about 1 to about 5, about 0.5 to about 4.5, about 0.5 to about 4, about 0.6 to about 3.5, about 0.6 to about 0.3, about 0.8 to about 3, or about 0.2 to about 1.

[0103] In some embodiments, when a redox initiator system is selected as the initiator, the molar ratio of water soluble free radical initiator to reducing agent is less than 10, less than 9, less than 8, less than 7, less than 6, less than 5, less than 4.8, less than 4.6, less than 4.4, less than 4.2, less than 4, less than 3.8, less than 3.6, less than 3.4, less than 3.2, less than 3, less than 2.8, less than 2.6, less than 2.4, less than 2.2, less than 2, less than 1.8, less than 1.6, less than 1.4, less than 1.2, less than 1, less than 0.8, less than 0.6, or less than 0.4. In some embodiments, when a redox initiator system is selected as the initiator, the molar ratio of water soluble free radical initiator to reducing agent is greater than 0.2, greater than 0.4, greater than 0.6, greater than 0.8, greater than 1, greater than 1.2, greater than 1.4, greater than 1.6, greater than 1.8, greater than 2, greater than 2.2, greater than 2.4, greater than 2.6, greater than 2.8, greater than 3, greater than 3.2, greater than 3.4, greater than 3.6, greater than 3.8, greater than 4, greater than 4.2, greater than 4.4, greater than 4.6, greater than 4.8, greater than 5, greater than 6, greater than 7, greater than 8, or greater than 9.

[0104] The polymerization temperature depends on the type of initiator used. In some embodiments, the polymerization reaction temperature is about 50°C to about 90°C, about 50°C to about 85°C, about 50°C to about 80°C, about 50°C to about 75°C, about 50°C to about 70°C, about 55°C to about 75°C, about 55°C to about 80°C, about 55°C to about 85°C, about 60°C to about 80°C, about 60°C to about 75°C, about 60°C to about 70°C, or about 55°C to about 70°C. When the polymerization reaction temperature is within the above range, higher reaction stability can be achieved, and the binder composition can exhibit better overall bonding performance.

[0105] In some embodiments, the reaction temperature of the polymerization is less than 90° C., less than 88° C., less than 86° C., less than 84° C., less than 82° C., less than 80° C., less than 78° C., less than 76° C., less than 74° C., less than 72° C., less than 70° C., less than 68° C., less than 66° C., less than 64° C., less than 62° C., less than 60° C., less than 58° C., less than 56° C., or less than 54° C. In some embodiments, the reaction temperature of the polymerization is greater than 50° C., greater than 52° C., greater than 54° C., greater than 56° C., greater than 58° C., greater than 60° C., greater than 62° C., greater than 64° C., greater than 66° C., greater than 68° C., greater than 70° C., greater than 72° C., greater than 74° C., greater than 76° C., greater than 78° C., greater than 80° C., greater than 82° C., greater than 84° C., or greater than 86° C.

[0106] In some embodiments, the total reaction time for the polymerization is about 20 hours to about 28 hours, about 20 hours to about 27.5 hours, about 20 hours to about 27 hours, about 20 hours to about 26.5 hours, about 20 hours to about 26 hours, about 20.5 hours to about 26 hours, about 21 hours to about 26 hours, about 21.5 hours to about 26 hours, about 22 hours to about 26 hours, about 22 hours to about 25.5 hours, about 22 hours to about 25 hours, about 22.5 hours to about 25 hours, about 23 hours to about 25 hours, about 23.5 hours to about 25 hours, or about 23.5 hours to about 24.5 hours.

[0107] In some embodiments, the total reaction time of the polymerization is less than 28 hours, less than 27.5 hours, less than 27 hours, less than 26.5 hours, less than 26 hours, less than 25.5 hours, less than 25 hours, less than 24.5 hours, less than 24 hours, less than 23.5 hours, less than 23 hours, less than 22.5 hours, less than 22 hours, less than 21.5 hours, less than 21 hours, or less than 20.5 hours. In some embodiments, the total reaction time of the polymerization is greater than 20 hours, greater than 20.5 hours, greater than 21 hours, greater than 21.5 hours, greater than 22 hours, greater than 22.5 hours, greater than 23 hours, greater than 23.5 hours, greater than 24 hours, greater than 24.5 hours, greater than 25 hours, greater than 25.5 hours, greater than 26 hours, greater than 26.5 hours, greater than 27 hours, or greater than 27.5 hours.

[0108] In some embodiments, the fifth suspension is sequestered for about 20 hours to about 28 hours, about 20.25 hours to about 28 hours, about 20.5 hours to about 28 hours, about 20.75 hours to about 28 hours, about 21 hours to about 28 hours, about 21 hours to about 27.75 hours, about 21 hours to about 27.5 hours, about 21 hours to about 27.25 hours, about 21 hours to about 27 hours, about 21.25 hours to about 27 hours, about 21.5 hours to about 27 hours, or about 21.75 hours to about 27 hours. The mixture is stirred for about 21.25 hours to about 27 hours, about 21.5 hours to about 27 hours, about 21.75 hours to about 27 hours, about 22 hours to about 27 hours, about 22 hours to about 26.75 hours, about 22 hours to about 26.5 hours, about 22 hours to about 26.25 hours, about 22 hours to about 26 hours, about 22.25 hours to about 26 hours, about 22.5 hours to about 26 hours, about 22.75 hours to about 26 hours, about 23 hours to about 26 hours, about 23 hours to about 25.75 hours, about 23 hours to about 25.5 hours, about 23 hours to about 25.25 hours, or about 23 hours to about 25 hours.

[0109] In some embodiments, the fifth suspension is stirred for less than 28 hours, less than 27.5 hours, less than 27 hours, less than 26.5 hours, less than 26 hours, less than 25.5 hours, less than 25 hours, less than 24.5 hours, less than 24 hours, less than 23.5 hours, less than 23 hours, less than 22.5 hours, less than 22 hours, less than 21.5 hours, less than 21 hours, or less than 20.5 hours. In some embodiments, the fifth suspension is stirred for more than 20 hours, more than 20.5 hours, more than 21 hours, more than 21.5 hours, more than 22 hours, more than 22.5 hours, more than 23 hours, more than 23.5 hours, more than 24 hours, more than 24.5 hours, more than 25 hours, more than 25.5 hours, more than 26 hours, more than 26.5 hours, more than 27 hours, or more than 27.5 hours.

[0110] In some embodiments, the fifth suspension is stirred at a speed of about 20 rpm to about 300 rpm, about 20 rpm to about 280 rpm, about 20 rpm to about 260 rpm, about 20 rpm to about 240 rpm, about 20 rpm to about 220 rpm, about 20 rpm to about 200 rpm, about 20 rpm to about 180 rpm, about 20 rpm to about 160 rpm, about 40 rpm to about 160 rpm, about 60 rpm to about 160 rpm, about 60 rpm to about 140 rpm, about 80 rpm to about 140 rpm, about 80 rpm to about 120 rpm, about 50 rpm to about 150 rpm, or about 50 rpm to about 200 rpm.

[0111] In some embodiments, the fifth suspension is stirred at a speed of less than 300 rpm, less than 280 rpm, less than 260 rpm, less than 240 rpm, less than 220 rpm, less than 200 rpm, less than 180 rpm, less than 160 rpm, less than 140 rpm, less than 120 rpm, less than 100 rpm, less than 80 rpm, less than 60 rpm, or less than 40 rpm. In some embodiments, the fifth suspension is stirred at a speed of greater than 20 rpm, greater than 40 rpm, greater than 60 rpm, greater than 80 rpm, greater than 100 rpm, greater than 120 rpm, greater than 140 rpm, greater than 160 rpm, greater than 180 rpm, greater than 200 rpm, greater than 220 rpm, greater than 240 rpm, greater than 260 rpm, or greater than 280 rpm.

[0112] In some embodiments, the proportion of the water-soluble free radical initiator is about 0.005% to about 0.05%, about 0.0075% to about 0.05%, about 0.01% to about 0.05%, about 0.01% to about 0.048%, about 0.01% to about 0.046%, about 0.01% to about 0.044%, about 0.01% to about 0.042%, about 0.01% to about 0.04%, about 0.01% to about 0.038%, about 0.01% to about 0.036%, about 0. In the binder composition, the proportion of the water-soluble initiator in the total weight of the monomers added is preferably 0.01% to about 0.034%, about 0.01% to about 0.032%, about 0.01% to about 0.03%, about 0.012% to about 0.03%, about 0.014% to about 0.03%, about 0.016% to about 0.03%, about 0.01% to about 0.028%, about 0.016% to about 0.026%, about 0.018% to about 0.026%, or about 0.02% to about 0.026%. When the proportion of the water-soluble initiator in the total weight of the monomers added in the binder composition is within the above range, a higher monomer conversion rate can be achieved, and the binder composition can exhibit better overall binding performance.

[0113] In some embodiments, the proportion of water-soluble free radical initiator is less than 0.05%, less than 0.048%, less than 0.046%, less than 0.044%, less than 0.042%, less than 0.04%, less than 0.038%, less than 0.036%, less than 0.034%, less than 0.032%, less than 0.03%, less than 0.028%, less than 0.026%, less than 0.024%, less than 0.022%, less than 0.02%, less than 0.018%, less than 0.016%, less than 0.014%, less than 0.012%, less than 0.01%, less than 0.008%, or less than 0.006% by weight, based on the total weight of monomers added in preparing the binder composition. In some embodiments, the proportion of water-soluble free radical initiator is greater than 0.005%, greater than 0.0075%, greater than 0.01%, greater than 0.012%, greater than 0.014%, greater than 0.016%, greater than 0.018%, greater than 0.02%, greater than 0.022%, greater than 0.024%, greater than 0.026%, greater than 0.028%, greater than 0.03%, greater than 0.032%, greater than 0.034%, greater than 0.036%, greater than 0.038%, greater than 0.04%, greater than 0.042%, greater than 0.044%, greater than 0.046%, or greater than 0.048% by weight, based on the total weight of monomers added in preparing the binder composition.

[0114] In some embodiments, the proportion of reducing agent is about 0.001% to about 0.03%, about 0.0025% to about 0.03%, about 0.005% to about 0.03%, about 0.005% to about 0.029%, about 0.005% to about 0.028%, about 0.005% to about 0.027%, about 0.005% to about 0.026%, about 0.005% to about 0.025%, about 0.005% to about 0.024%, about 0.005% by weight, based on the total weight of monomers added in preparing the binder composition. % to about 0.023%, about 0.005% to about 0.022%, about 0.005% to about 0.021%, about 0.005% to about 0.02%, about 0.005% to about 0.019%, about 0.005% to about 0.018%, about 0.005% to about 0.017%, about 0.005% to about 0.016%, about 0.005% to about 0.015%, about 0.006% to about 0.015%, about 0.007% to about 0.015%, about 0.007% to about 0.02%, or about 0.007% to about 0.025%.

[0115] In some embodiments, the percentage of reducing agent is less than 0.03%, less than 0.029%, less than 0.028%, less than 0.027%, less than 0.026%, less than 0.025%, less than 0.024%, less than 0.023%, less than 0.022%, less than 0.021%, less than 0.02%, less than 0.019%, less than 0.018%, less than 0.017%, less than 0.016%, less than 0.015%, less than 0.014%, less than 0.013%, less than 0.012%, less than 0.011%, less than 0.01%, less than 0.008%, less than 0.006%, or less than 0.004% by weight based on the total weight of monomers added in preparing the binder composition. In some embodiments, the proportion of reducing agent is greater than 0.001%, greater than 0.0025%, greater than 0.005%, greater than 0.006%, greater than 0.007%, greater than 0.008%, greater than 0.009%, greater than 0.01%, greater than 0.011%, greater than 0.012%, greater than 0.013%, greater than 0.014%, greater than 0.015%, greater than 0.016%, greater than 0.017%, greater than 0.018%, greater than 0.019%, greater than 0.020%, greater than 0.021%, greater than 0.022%, greater than 0.023%, greater than 0.024%, greater than 0.025%, greater than 0.026%, greater than 0.027%, greater than 0.028%, greater than 0.029%, greater than 0.030%, greater than 0.031%, greater than 0.032%, greater than 0.033%, greater than 0.034%, greater than 0.035%, greater than 0.036%, greater than 0.037%, greater than 0.038%, greater than 0.039%, greater than 0.040%, greater than 0.041%, greater than 0.042%, greater than 0.043%, greater than 0.044%, greater than 0.045%, greater than 0.046%, greater than 0.047%, greater than 0.048%, greater than 0.049%, greater than 0.050%, greater than 0.050%, greater than 0.051%, greater than 0.052%, greater than 0.500%, greater than 0.501%, greater than 0.502%, greater than 0.503%, greater than 0.5 greater than 0.016%, greater than 0.017%, greater than 0.018%, greater than 0.019%, greater than 0.02%, greater than 0.021%, greater than 0.022%, greater than 0.023%, greater than 0.024%, greater than 0.025%, greater than 0.026%, greater than 0.027%, or greater than 0.028%.

[0116] In some embodiments, the neutralizing solution is prepared by dissolving a neutralizing agent in water. In some embodiments, the sixth suspension is formed in step 106 by dropwise adding the neutralizing solution to the fifth suspension. The neutralizing agent described above in step 101 may be selected. In some embodiments, the neutralizing agent applied in step 101 may correspond to the neutralizing agent used in step 106. In some embodiments, the neutralizing agents applied in steps 101 and 106 may not be the same.

[0117] In some embodiments, the temperature of the fifth suspension is lowered to about 20°C to about 40°C, about 20°C to about 39°C, about 20°C to about 38°C, about 20°C to about 37°C, about 20°C to about 36°C, about 20°C to about 35°C, about 20°C to about 34°C, about 20°C to about 33°C, about 20°C to about 32°C, about 20°C to about 31°C, about 20°C to about 30°C, about 21°C to about 35°C, about 22°C to about 35°C, about 23°C to about 35°C, about 24°C to about 35°C, or about 25°C to about 35°C before adding the neutralization solution to form the sixth suspension. In some embodiments, the temperature of the fifth suspension is reduced by less than 40°C, less than 39°C, less than 38°C, less than 37°C, less than 36°C, less than 35°C, less than 34°C, less than 33°C, less than 32°C, less than 31°C, less than 30°C, less than 29°C, less than 28°C, less than 27°C, less than 26°C, less than 25°C, less than 24°C, less than 23°C, less than 22°C, or less than 21°C prior to adding the neutralization solution to form the sixth suspension. In some embodiments, the temperature of the fifth suspension is reduced to greater than 20°C, greater than 21°C, greater than 22°C, greater than 23°C, greater than 24°C, greater than 25°C, greater than 26°C, greater than 27°C, greater than 28°C, greater than 29°C, greater than 30°C, greater than 31°C, greater than 32°C, greater than 33°C, greater than 34°C, greater than 35°C, greater than 36°C, greater than 37°C, greater than 38°C, or greater than 39°C prior to adding the neutralization solution to form the sixth suspension.

[0118] In some embodiments, the total proportion of neutralizing agent is from about 35% to about 68%, from about 35% to about 66%, from about 35% to about 64%, from about 35% to about 62%, from about 35% to about 60%, from about 35% to about 59%, from about 35% to about 58%, from about 35% to about 57%, ... 5% to about 56%, about 35% to about 55%, about 35% to about 54%, about 35% to about 53%, about 35% to about 52%, about 35% to about 51%, about 35% to about 50%, about 36% to about 50%, about 37% to about 50%, about 38% to about 50%, about 39% to about 50%, about 40% to about 50%, about 35% to about 45%, or about 42% to about 52%.

[0119] In some embodiments, the total proportion of neutralizing agent is less than 68%, 66%, 64%, 62%, 60%, 58%, 56%, 54%, 52%, 50%, 48%, 46%, 44%, 42%, 40%, 38%, or 36% by mole, based on the total moles of monomer units in the copolymer in the binder composition. In some embodiments, the total proportion of neutralizing agent is greater than 35%, greater than 37%, greater than 40%, greater than 42%, 44%, 46%, greater than 48%, 50%, greater than 52%, greater than 54%, 56%, greater than 58%, greater than 60%, greater than 62%, greater than 64%, or greater than 66% by mole, based on the total moles of monomer units in the copolymer in the binder composition.

[0120] In some embodiments, the neutralization solution is added dropwise to the fifth suspension over a period of about 15 to about 120 minutes, about 20 to about 120 minutes, about 30 to about 120 minutes, about 30 to about 110 minutes, about 30 to about 100 minutes, about 30 to about 90 minutes, about 40 to about 90 minutes, about 40 to about 80 minutes, about 45 to about 80 minutes, about 45 to about 75 minutes, about 50 to about 75 minutes, about 50 to about 70 minutes, about 55 to about 70 minutes, or about 55 to about 65 minutes. In some embodiments, the neutralization solution is added dropwise to the fifth suspension over a period of less than 120 minutes, less than 110 minutes, less than 100 minutes, less than 90 minutes, less than 80 minutes, less than 70 minutes, less than 60 minutes, less than 50 minutes, less than 40 minutes, less than 30 minutes, or less than 20 minutes. In some embodiments, the neutralization solution is added dropwise to the fifth suspension for a period of more than 15 minutes, more than 20 minutes, more than 30 minutes, more than 40 minutes, more than 50 minutes, more than 60 minutes, more than 70 minutes, or more than 80 minutes.

[0121] In some embodiments, the fifth suspension is stirred during the addition of the neutralization solution and neutralization for a period of about 1 hour to about 6 hours, about 1 hour to about 5.75 hours, about 1 hour to about 5.5 hours, about 1 hour to about 5.25 hours, about 1 hour to about 5 hours, about 1 hour to about 4.75 hours, about 1 hour to about 4.5 hours, about 1 hour to about 4.25 hours, about 1 hour to about 4 hours, about 1.25 hours to about 4 hours, about 1.5 hours to about 4 hours, about 1.75 hours to about 4 hours, about 2 hours to about 4 hours, about 2.25 hours to about 4 hours, about 2.5 hours to about 4 hours, about 2.5 hours to about 3.75 hours, 2.5 hours to about 3.5 hours, 2.5 hours to about 4 hours, or about 2 hours to about 3.5 hours.

[0122] In some embodiments, the fifth suspension is stirred during the addition of the neutralization solution and neutralization for less than 6 hours, less than 5.75 hours, less than 5.5 hours, less than 5.25 hours, less than 5 hours, less than 4.75 hours, less than 4.5 hours, less than 4.25 hours, less than 4 hours, less than 3.75 hours, less than 3.5 hours, less than 3.25 hours, less than 3 hours, less than 2.75 hours, less than 2.5 hours, less than 2.25 hours, less than 2 hours, less than 1.75 hours, or less than 1.5 hours. In some embodiments, the fifth suspension is stirred during the addition of the neutralization solution and neutralization for more than 1 hour, more than 1.25 hours, more than 1.5 hours, more than 1.75 hours, more than 2 hours, more than 2.25 hours, more than 2.5 hours, more than 2.75 hours, more than 3 hours, more than 3.25 hours, more than 3.5 hours, more than 3.75 hours, more than 4 hours, more than 4.25 hours, more than 4.5 hours, more than 4.75 hours, more than 5 hours, more than 5.25 hours, or more than 5.5 hours.

[0123] In some embodiments, the fifth suspension is stirred at a speed of about 20 rpm to about 300 rpm, about 20 rpm to about 280 rpm, about 20 rpm to about 260 rpm, about 20 rpm to about 240 rpm, about 20 rpm to about 220 rpm, about 20 rpm to about 200 rpm, about 20 rpm to about 180 rpm, about 20 rpm to about 160 rpm, about 40 rpm to about 160 rpm, about 60 rpm to about 160 rpm, about 60 rpm to about 140 rpm, about 80 rpm to about 140 rpm, about 80 rpm to about 120 rpm, about 50 rpm to about 150 rpm, or about 50 rpm to about 200 rpm.

[0124] In some embodiments, the fifth suspension is stirred at a speed of less than 300 rpm, less than 280 rpm, less than 260 rpm, less than 240 rpm, less than 220 rpm, less than 200 rpm, less than 180 rpm, less than 160 rpm, less than 140 rpm, less than 120 rpm, less than 100 rpm, less than 80 rpm, less than 60 rpm, or less than 40 rpm. In some embodiments, the fifth suspension is stirred at a speed of greater than 20 rpm, greater than 40 rpm, greater than 60 rpm, greater than 80 rpm, greater than 100 rpm, greater than 120 rpm, greater than 140 rpm, greater than 160 rpm, greater than 180 rpm, greater than 200 rpm, greater than 220 rpm, greater than 240 rpm, greater than 260 rpm, or greater than 280 rpm.

[0125] In some embodiments, the sixth suspension is filtered in step 107 to form a binder composition.

[0126] The purpose of adding the neutralizing agent in steps 101 and 106 is to neutralize the carboxylic acid group-containing monomer added in step 102 and produce a binder composition that is inherently weakly alkaline. Exposing the binder composition to acidic conditions is undesirable because it may disrupt the dispersion of the binder composition.

[0127] In some embodiments, the structural unit (a) derived from a carboxylic acid group-containing monomer contains a carboxylate salt group. In some embodiments, the carboxylate salt group is a salt of a carboxylic acid group. In some embodiments, the structural unit (a) derived from a carboxylic acid group-containing monomer contains a combination of a carboxylate salt group and a carboxylic acid group. In some embodiments, the structural unit (a) contains an alkali metal carboxylate salt group. Examples of alkali metals that form alkali metal carboxylate salts include lithium, sodium, and potassium. In some embodiments, the structural unit (a) contains an ammonium carboxylate salt group.

[0128] In some embodiments, the molar ratio of carboxylic acid groups to carboxylate salt groups in the copolymer is from about 0 to about 0.2, from about 0 to about 0.19, from about 0 to about 0.18, from about 0 to about 0.17, from about 0 to about 0.16, from about 0 to about 0.15, from about 0 to about 0.14, from about 0 to about 0.13, from about 0 to about 0.16, from about 0 to about 0.15, from about 0 to about 0.14, from about 0 to about 0.13, from about 0 to about 0.12, from about 0 to about 0.11, from about 0 to about 0.1, from about 0 to about 0.09, from about 0 to about 0.08, from about 0 to about 0.07, from about 0 to about 0.06, from about 0 to about 0.05, from about 0.01 to about 0.1, from about 0.02 to about 0.12, or from about 0.01 to about 0.15.

[0129] In some embodiments, the molar ratio of carboxylic acid groups to carboxylate salt groups in the copolymer is less than 0.2, less than 0.19, less than 0.18, less than 0.17, less than 0.16, less than 0.15, less than 0.14, less than 0.13, less than 0.12, less than 0.11, less than 0.1, less than 0.09, less than 0.08, less than 0.07, less than 0.06, less than 0.05, less than 0.04, less than 0.03, or less than 0.02. In some embodiments, the molar ratio of carboxylic acid groups to carboxylate salt groups in the copolymer is greater than 0, greater than 0.01, greater than 0.02, greater than 0.03, greater than 0.04, greater than 0.05, greater than 0.06, greater than 0.07, greater than 0.08, greater than 0.09, greater than 0.1, greater than 0.11, greater than 0.12, greater than 0.13, greater than 0.14, greater than 0.15, greater than 0.16, greater than 0.17, or greater than 0.18.

[0130] In some embodiments, the proportion of structural unit (a) in the copolymer is from about 33% to about 70%, from about 33% to about 69%, from about 33% to about 68%, from about 33% to about 67%, from about 33% to about 66%, from about 33% to about 65%, from about 33% to about 64%, from about 33% to about 63%, from about 33% to about 62%, from about 33% to about 61%, from about 33% to about 60%, from about 33% to about 50%, or from about 33% to about 55% by mole, based on the total number of moles of monomer units in the copolymer in the binder composition. 9%, about 33% to about 58%, about 33% to about 57%, about 33% to about 56%, about 33% to about 55%, about 33% to about 54%, about 33% to about 53%, about 33% to about 52%, about 33% to about 51%, about 33% to about 50%, about 34% to about 50%, about 35% to about 50%, about 36% to about 50%, about 37% to about 50%, about 38% to about 50%, about 39% to about 50%, about 40% to about 50%, about 35% to about 60%, or about 40% to about 55%.

[0131] In some embodiments, the proportion of structural units (a) in the copolymer is less than 70%, less than 68%, less than 66%, less than 64%, less than 62%, less than 60%, less than 58%, less than 56%, less than 54%, less than 52%, less than 50%, less than 48%, less than 46%, less than 44%, less than 42%, less than 40%, less than 38%, less than 36%, or less than 34% by mole, based on the total number of moles of monomer units in the copolymer in the binder composition. In some embodiments, the proportion of structural units (a) in the copolymer is greater than 33%, greater than 34%, greater than 36%, greater than 38%, greater than 40%, greater than 42%, greater than 44%, greater than 46%, greater than 48%, greater than 50%, greater than 52%, greater than 54%, greater than 56%, greater than 58%, greater than 60%, greater than 62%, greater than 64%, or greater than 66% by mole, based on the total number of moles of monomer units in the copolymer in the binder composition.

[0132] In some embodiments, the proportion of structural units (b) in the copolymer is from about 10% to about 35%, from about 10% to about 34%, from about 10% to about 33%, from about 10% to about 32%, from about 10% to about 31%, from about 10% to about 30%, from about 11% to about 30%, from about 12% to about 30%, from about 13% to about 14%, from about 15% to about 16%, from about 17% to about 18%, from about 19% to about 20%, from about 21% to about 22%, from about 23% to about 24%, from about 25% to about 26%, from about 27% to about 28%, from about 29% to about 30%, from about 31% to about 32%, from about 33% to about 33%, from about 34% to about 34%, from about 35% to about 35%, from about 36% to about 36%, from about 37% to about 37%, from about 38% to about 38%, from about 39% to about 40%, from about 41% to about 42%, from about 43% to about 44%, from about 45% to about 45%, from about 46% to about 47%, from about 48% to about 49%, from about 49% to about 50%, from about 51% to about 52%, from about 53% to about 54%, from about 55% to about 56%, from about 57% to about 58%, from about 59% to about 60%, from about 61% to about 62%, from about 63% to about 64%, from about 65% to about 66%, from about 67% to about 68%, from about 69% to about 70%, from about 3% to about 30%, about 14% to about 30%, about 15% to about 30%, about 16% to about 30%, about 17% to about 30%, about 18% to about 30%, about 19% to about 30%, about 20% to about 30%, about 20% to about 29%, about 20% to about 28%, about 20% to about 27%, about 20% to about 26%, about 20% to about 25%, about 15% to about 28%, or about 15% to about 34%.

[0133] In some embodiments, the proportion of structural units (b) in the copolymer is less than 35%, less than 34%, less than 33%, less than 32%, less than 31%, less than 30%, less than 29%, less than 28%, less than 27%, less than 26%, less than 25%, less than 24%, less than 23%, less than 22%, less than 21%, less than 20%, less than 19%, less than 18%, less than 17%, less than 16%, less than 15%, less than 14%, less than 13%, or less than 12% by mole, based on the total number of moles of monomer units in the copolymer in the binder composition. In some embodiments, the proportion of structural units (b) in the copolymer is greater than 10%, greater than 11%, greater than 12%, greater than 13%, greater than 14%, greater than 15%, greater than 16%, greater than 17%, greater than 18%, greater than 19%, greater than 20%, greater than 21%, greater than 22%, greater than 23%, greater than 24%, greater than 25%, greater than 26%, greater than 27%, greater than 28%, greater than 29%, greater than 30%, greater than 31%, greater than 32%, or greater than 33% by mole, based on the total number of moles of monomer units in the copolymer in the binder composition.

[0134] In some embodiments, the proportion of structural units (c) in the copolymer is from about 10% to about 30%, from about 11% to about 30%, from about 12% to about 30%, from about 13% to about 30%, from about 14% to about 30%, from about 15% to about 30%, from about 16% to about 30%, from about 17% to about 30%, from about 18% to about 30%, from about 19% to about 30%, or from about 20% to about 20% by mole, based on the total number of moles of monomer units in the copolymer in the binder composition. 0%, about 20% to about 30%, about 20% to about 29%, about 20% to about 28%, about 20% to about 27%, about 20% to about 26%, about 20% to about 25%, about 11% to about 25%, about 12% to about 25%, about 13% to about 25%, about 14% to about 25%, about 15% to about 25%, about 16% to about 27%, about 17% to about 27%, about 18% to about 27%, about 19% to about 27%, or about 10% to about 27%.

[0135] In some embodiments, the proportion of structural units (c) in the copolymer is less than 30%, less than 29%, less than 28%, less than 27%, less than 26%, less than 25%, less than 24%, less than 23%, less than 22%, less than 21%, less than 20%, less than 19%, less than 18%, less than 17%, less than 16%, less than 15%, less than 14%, less than 13%, or less than 12% by mole, based on the total number of moles of monomer units in the copolymer in the binder composition. In some embodiments, the proportion of structural units (c) in the copolymer is greater than 10%, greater than 11%, greater than 12%, greater than 13%, greater than 14%, greater than 15%, greater than 16%, greater than 17%, greater than 18%, greater than 19%, greater than 20%, greater than 21%, greater than 22%, greater than 23%, greater than 24%, greater than 25%, greater than 26%, greater than 27%, or greater than 28% by mole, based on the total number of moles of monomer units in the copolymer in the binder composition.

[0136] In some embodiments, the combined proportion of structural units (a) and structural units (c) in the copolymer is, by mole, about 65% to about 90%, about 65% to about 89%, about 65% to about 88%, about 65% to about 87%, about 65% to about 86%, about 65% to about 85%, about 65% to about 84%, about 65% to about 83%, about 65% to about 82%, about 65% to about 81%, about 65% to about 80%, about 66% to about 80%, about 67% to about 80%, about 68% to about 80%, about 69% to about 80%, about 70% to about 80%, about 65% to about 75%, or about 70% to about 85%, based on the total moles of monomer units in the copolymer in the binder composition.

[0137] In some embodiments, the combined proportion of structural units (a) and (c) in the copolymer is less than 90%, 88%, 86%, 84%, 82%, 80%, 78%, 76%, 74%, 72%, 70%, 68%, or 66% by mole, based on the total number of moles of monomer units in the copolymer in the binder composition. In some embodiments, the combined proportion of structural units (a) and (c) in the copolymer is greater than 65%, 67%, 70%, 72%, 74%, 76%, 78%, 80%, 82%, 84%, 86%, or 88% by mole, based on the total number of moles of monomer units in the copolymer in the binder composition.

[0138] In some embodiments, the molar ratio of the total of structural units (a) and structural units (c) to structural unit (b) in the copolymer is from about 1 to about 7, from about 1 to about 6.8, from about 1 to about 6.6, from about 1 to about 6.4, from about 1 to about 6.2, from about 1 to about 6, from about 1 to about 5.8, from about 1 to about 5.6, from about 1 to about 5.4, from about 1 to about 5.2, from about 1 to about 5, from about 1 to about 4.8, from about 1 to about 4.6, from about 1 to about 4.4, from about 1 to about 4.2, from about 1 to about 4, from about 1 to about 3.8, from about 1.2 to about 3.8, from about 1.4 to about 3.8, from about 2 to about 6, from about 2 to about 4, from about 3 to about 5, or from about 3 to about 7.

[0139] In some embodiments, the molar ratio of the sum of structural units (a) and structural units (c) to structural unit (b) in the copolymer is less than 7, less than 6.8, less than 6.6, less than 6.4, less than 6.2, less than 6, less than 5.8, less than 5.6, less than 5.4, less than 5.2, less than 5, less than 4.8, less than 4.6, less than 4.4, less than 4.2, less than 4, less than 3.8, less than 3.6, less than 3.4, less than 3.2, less than 3, less than 2.8, less than 2.6, less than 2.4, less than 2.2, less than 2, less than 1.8, less than 1.6, less than 1.4, or less than 1.2. In some embodiments, the molar ratio of the sum of structural units (a) and structural units (c) to structural unit (b) in the copolymer is greater than 1, greater than 1.2, greater than 1.4, greater than 1.6, greater than 1.8, greater than 2, greater than 2.2, greater than 2.4, greater than 2.6, greater than 2.8, greater than 3, greater than 3.2, greater than 3.4, greater than 3.6, greater than 3.8, greater than 4, greater than 4.2, greater than 4.4, greater than 4.6, greater than 4.8, greater than 5, greater than 5.2, greater than 5.4, greater than 5.6, greater than 5.8, greater than 6, greater than 6.2, greater than 6.4, greater than 6.6, or greater than 6.8.

[0140] In some embodiments, structural unit (a) and structural unit (b) constitute the hydrophilic portion of the copolymer, hi some embodiments, structural unit (c) constitutes the hydrophobic portion of the copolymer.

[0141] In some embodiments, the molar ratio of the total of structural units (a) and structural units (b) to structural unit (c) in the copolymer is from about 1 to about 7, from about 1 to about 6.8, from about 1 to about 6.6, from about 1 to about 6.4, from about 1 to about 6.2, from about 1 to about 6, from about 1 to about 5.8, from about 1 to about 5.6, from about 1 to about 5.4, from about 1 to about 5.2, from about 1 to about 5, from about 1 to about 4.8, from about 1 to about 4.6, from about 1 to about 4.4, from about 1 to about 4.2, from about 1 to about 4, from about 1 to about 3.8, from about 1 to about 3.6, from about 1 to about 3.4, from about 1.2 to about 3.4, from about 1.4 to about 3.4, from about 1.5 to about 6.7, from about 1.5 to about 5, from about 1.5 to about 4.8, or from about 1.5 to about 4.

[0142] In some embodiments, the molar ratio of the sum of structural units (a) and structural units (b) to structural units (c) in the copolymer is less than 7, less than 6.8, less than 6.6, less than 6.4, less than 6.2, less than 6, less than 5.8, less than 5.6, less than 5.4, less than 5.2, less than 5, less than 4.8, less than 4.6, less than 4.4, less than 4.2, less than 4, less than 3.8, less than 3.6, less than 3.4, less than 3.2, less than 3, less than 2.8, less than 2.6, less than 2.4, less than 2.2, less than 2, less than 1.8, less than 1.6, less than 1.4, or less than 1.2. In some embodiments, the molar ratio of the sum of structural units (a) and structural units (b) to structural unit (c) in the copolymer is greater than 1, greater than 1.2, greater than 1.4, greater than 1.6, greater than 1.8, greater than 2, greater than 2.2, greater than 2.4, greater than 2.6, greater than 2.8, greater than 3, greater than 3.2, greater than 3.4, greater than 3.6, greater than 3.8, greater than 4, greater than 4.2, greater than 4.4, greater than 4.6, greater than 4.8, greater than 5, greater than 5.2, greater than 5.4, greater than 5.6, greater than 5.8, greater than 6, greater than 6.2, greater than 6.4, greater than 6.6, or greater than 6.8.

[0143] The addition of ester group-containing monomers in the preparation of the binder compositions disclosed herein has been found to result in degradation of electrochemical performance. In some embodiments, the binder composition does not have structural units derived from ester group-containing monomers. In some embodiments, the ester group-containing monomers are C1-C 20 Alkyl acrylate, C1-C 20In some embodiments, the ester group-containing monomer is methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, sec-butyl acrylate, tert-butyl acrylate, pentyl acrylate, hexyl acrylate, heptyl acrylate, octyl acrylate, 3,3,5-trimethylhexyl acrylate, 2-ethylhexyl acrylate, nonyl acrylate, decyl acrylate, lauryl acrylate, n-tetradecyl acrylate, octadecyl acrylate, cyclohexyl acrylate, phenyl acrylate, methoxymethyl acrylate, methoxyethyl acrylate, ethoxymethyl acrylate, ethoxyethyl acrylate, perfluorooctyl acrylate, stearyl acrylate, or a combination thereof. In some embodiments, the ester group-containing monomer is cyclohexyl acrylate, cyclohexyl methacrylate, isobornyl acrylate, isobornyl methacrylate, 3,3,5-trimethylcyclohexyl acrylate, or a combination thereof. In some embodiments, the ester group-containing monomer is methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, sec-butyl methacrylate, tert-butyl methacrylate, isobutyl methacrylate, n-pentyl methacrylate, isopentyl methacrylate, hexyl methacrylate, heptyl methacrylate, octyl methacrylate, 2-ethylhexyl methacrylate, nonyl methacrylate, decyl methacrylate, lauryl methacrylate, n-tetradecyl methacrylate, stearyl methacrylate, 2,2,2-trifluoroethyl methacrylate, phenyl methacrylate, benzyl methacrylate, or a combination thereof.

[0144] In some embodiments, the binder composition does not contain structural units derived from conjugated diene group-containing monomers. Examples of conjugated diene group-containing monomers include aliphatic conjugated diene monomers such as 1,3-butadiene, 2-methyl-1,3-butadiene, 2,3-dimethyl-1,3-butadiene, and 2-chloro-1,3-butadiene, substituted linear conjugated pentadiene, and substituted side-chain conjugated hexadiene.

[0145] In some embodiments, the binder composition does not include structural units derived from aromatic vinyl group-containing monomers. Examples of aromatic vinyl group-containing monomers include styrene, α-methylstyrene, vinyltoluene, and divinylbenzene.

[0146] In some embodiments, the pH of the binder composition is from about 7 to about 9, from about 7 to about 8.9, from about 7 to about 8.8, from about 7 to about 8.7, from about 7 to about 8.6, from about 7 to about 8.5, from about 7 to about 8.4, from about 7 to about 8.3, from about 8 to about 8.2, from about 7 to about 8.1, from about 7 to about 8, from about 7.1 to about 9, from about 7.2 to about 9, from about 7.3 to about 9, from about 7.4 to about 9, from about 7.5 to about 9, from about 7.6 to about 9, from about 7.7 to about 9, from about 7.8 to about 9, from about 7.9 to about 9, or from about 8 to about 9.

[0147] In certain embodiments, the pH of the binder composition is less than 9, less than 8.9, less than 8.8, less than 8.7, less than 8.6, less than 8.5, less than 8.4, less than 8.3, less than 8.2, less than 8.1, less than 8, less than 7.9, less than 7.8, less than 7.7, less than 7.6, less than 7.5, less than 7.4, less than 7.3, or less than 7.2. In certain embodiments, the pH of the binder composition is greater than 7, greater than 7.1, greater than 7.2, greater than 7.3, greater than 7.4, greater than 7.5, greater than 7.6, greater than 7.7, greater than 7.8, greater than 7.9, greater than 8, greater than 8.1, greater than 8.2, greater than 8.3, greater than 8.4, greater than 8.5, greater than 8.6, greater than 8.7, or greater than 8.8.

[0148] In some embodiments, the viscosity of the binder composition is from about 10,000 mPa·s to about 50,000 mPa·s, from about 10,000 mPa·s to about 47,500 mPa·s, from about 10,000 mPa·s to about 45,000 mPa·s, from about 10,000 mPa·s to about 42,500 mPa·s, from about 10,000 mPa·s to about 4000 mPa·s, or from about 10,000 mPa·s to about 45,000 mPa·s. 0mPa·s, 10,000mPa·s~approx. 3,7500mPa·s, 10,000mPa·s~approx. 35,000mPa·s, 10,000mPa·s~approx. 32,5 00mPa·s, 10,000mPa·s~approx. 30,000mPa·s, 10,000mPa·s~approx. 29,000mPa·s, approx. 10,000mPa·s~approx. 28, 000mPa·s, approximately 10,000mPa·s~approx. 27,000mPa·s, approximately 10,000mPa·s~approximately 26,000mPa·s, approximately 10,000mPa·s~ Approx. 25,000mPa s, Approx. 10,000mPa s~Approx. 24,000mPa s, Approx. 10,000mPa s~Approx. 23,000mPa s, Approx. 10,000mPa ·s to about 22,000 mPa·s, about 10,000 mPa·s to about 21,000 mPa·s, about 10,000 mPa·s to about 20,000 mPa·s, about 15,000 mPa·s to about 30,000 mPa·s, about 15,000 mPa·s to about 25,000 mPa·s, and about 15,000 mPa·s to about 35,000 mPa·s.

[0149] In some embodiments, the viscosity of the binder composition is less than 50,000 mPa·s, less than 47,500 mPa·s, less than 45,000 mPa·s, less than 42,500 mPa·s, less than 40,000 mPa·s, less than 37,500 mPa·s, less than 35,000 mPa·s, less than 32,500 mPa·s, less than 30,000 mPa·s, less than 27,500 mPa·s, less than 25,000 mPa·s, less than 22,500 mPa·s, less than 20,000 mPa·s, less than 17,500 mPa·s, less than 15,000 mPa·s, or less than 12,500 mPa·s. In some embodiments, the viscosity of the binder composition is greater than 10,000 mPa·s, greater than 12,500 mPa·s, greater than 15,000 mPa·s, greater than 17,500 mPa·s, greater than 20,000 mPa·s, greater than 22,500 mPa·s, greater than 25,000 mPa·s, greater than 27,500 mPa·s, greater than 30,000 mPa·s, greater than 32,500 mPa·s, greater than 35,000 mPa·s, greater than 37,500 mPa·s, greater than 40,000 mPa·s, greater than 42,500 mPa·s, greater than 45,000 mPa·s, or greater than 47,500 mPa·s.

[0150] In some embodiments, the solids content of the binder composition is from about 5% to about 10%, from about 5% to about 9.9%, from about 5% to about 9.8%, from about 5% to about 9.7%, from about 5% to about 9.6%, from about 5% to about 9.5%, from about 5% to about 9.4%, from about 5% to about 9.3%, from about 5% to about 9.2%, from about 5% to about 9.1%, from about 5% to about 9%, from about 5.1% to about 9%, from about 5.2% to about 9%, from about 5.3% to about 9%, from about 5.4% to about 9%, from about 5.5% to about 9%, from about 5.6% to about 9%, from about 5.7% to about 9%, from about 5.8% to about 9%, from about 5.9 ...9% to about 9%, from about 5.1% to about 0.5% to about 9%, about 5.6% to about 9%, about 5.7% to about 9%, about 5.8% to about 9%, about 5.9% to about 9%, about 6% to about 9%, about 6% to about 8.9%, about 6% to about 8.8%, about 6% to about 8.7%, about 6% to about 8.6%, about 6% to about 8.5%, about 6% to about 8.4%, about 6% to about 8.3%, about 6% to about 8.2%, about 6% to about 8.1%, about 6% to about 8%, about 6% to about 9.8%, about 6% to about 9.6%, about 6% to about 9.4%, or about 6% to about 9.2%.

[0151] In some embodiments, the solids content of the binder composition is less than 10%, less than 9.8%, less than 9.6%, less than 9.4%, less than 9.2%, less than 9%, less than 8.8%, less than 8.6%, less than 8.4%, less than 8.2%, less than 8%, less than 7.8%, less than 7.6%, less than 7.4%, less than 7.2%, less than 7%, less than 6.8%, less than 6.6%, less than 6.4%, less than 6.2%, less than 6%, less than 5.8%, less than 5.6%, less than 5.4%, or less than 5.2% by weight, based on the total weight of the binder composition. In some embodiments, the solids content of the binder composition is greater than 5%, greater than 5.2%, greater than 5.4%, greater than 5.6%, greater than 5.8%, greater than 6%, greater than 6.2%, greater than 6.4%, greater than 6.6%, greater than 6.8%, greater than 7%, greater than 7.2%, greater than 7.4%, greater than 7.6%, greater than 7.8%, greater than 8%, greater than 8.2%, greater than 8.4%, greater than 8.6%, greater than 8.8%, greater than 9%, greater than 9.2%, greater than 9.4%, greater than 9.6%, or greater than 9.8% by weight, based on the total weight of the binder composition.

[0152] In some embodiments, the weight average molecular weight of the binder composition is from about 50,000 g / mol to about 200,000 g / mol, from about 55,000 g / mol to about 200,000 g / mol, from about 60,000 g / mol to about 200,000 g / mol, or from about 65. 000g / mol~about 200,000g / mol, about 70,000g / mol~about 200,000g / mol, about 75,000g / mol~about 200,000g / mol, about 80,000g / mol~about 200,000g / mol, about 85,0 00g / mol~about 200,000g / mol, about 90,000g / mol~about 200,000g / mol, about 90,000g / mol~about 190,000g / mol, about 90,000g / mol~about 180,000g / mol, about 90,000 g / mol to about 170,000 g / mol, about 90,000 g / mol to about 160,000 g / mol, about 95,000 g / mol to about 160,000 g / mol, about 100,000 g / mol to about 160,000 g / mol, about 100,000 g / mol to about 155,000 g / mol, about 100,000 g / mol to about 150,000 g / mol, about 100,000 g / mol to about 145,000 g / mol, or about 100,000 g / mol to about 140,000 g / mol. When the weight-average molecular weight of the binder composition is not more than the upper limit, the coatability of the binder composition is ensured and the adhesive strength of the binder composition can be improved, thereby obtaining a smooth binder composition layer. On the other hand, when the weight average molecular weight of the binder composition is not less than the above-specified lower limit, the binding properties of the binder composition are ensured, and the adhesive strength and secondary battery cycle characteristics of the binder composition can be improved.

[0153] In some embodiments, the weight average molecular weight of the binder composition is less than 200,000 g / mol, less than 195,000 g / mol, less than 190,000 g / mol, less than 185,000 g / mol, less than 180,000 g / mol, less than 175,000 g / mol, less than 170,000 g / mol, less than 165,000 g / mol, less than 160,000 g / mol, less than 1 less than 55,000 g / mol, less than 150,000 g / mol, less than 145,000 g / mol, less than 140,000 g / mol, less than 135,000 g / mol, less than 130,000 g / mol, less than 125,000 g / mol, less than 120,000 g / mol, less than 115,000 g / mol, less than 110,000 g / mol, less than 105,000 g / mol, less than 100,000 g / mol, less than 95,000 g / mol, less than 90,000 g / mol, less than 85,000 g / mol, less than 80,000 g / mol, less than 75,000 g / mol, less than 70,000 g / mol, less than 65,000 g / mol, or less than 60,000 g / mol. In some embodiments, the weight average molecular weight of the binder composition is greater than 50,000 g / mol, greater than 55,000 g / mol, greater than 60,000 g / mol, greater than 65,000 g / mol, greater than 70,000 g / mol, greater than 75,000 g / mol, greater than 80,000 g / mol, greater than 85,000 g / mol, greater than 90,000 g / mol, greater than 95,000 g / mol, greater than 10,000 g / mol, greater than 105,000 g / mol, greater than 110,000 g / mol, greater than 115,000 g / mol, greater than 120,000 g / mol, greater than 130,000 g / mol, greater than 140,000 g / mol, greater than 150,000 g / mol, greater than 160,000 g / mol, greater than 170,000 g / mol, greater than 180,000 g / mol, greater than 190,000 g / mol, greater than 200,000 g / mol, greater than 210,000 g / mol, greater than 220,000 g / mol, greater than 230,000 g / mol, greater than 240,000 g / mol, greater than 250,000 g / mol, greater than 260,000 g / mol, greater than 270,000 g / mol, greater than 280,000 g / mol, greater than 290,000 g / mol, greater than 300,000 g / mol, greater than 310,000 g / mol, greater than 320,000 g / mol, greater than 330,000 g / mol, greater than 3 g / mol, greater than 125,000 g / mol, greater than 130,000 g / mol, greater than 135,000 g / mol, greater than 140,000 g / mol, greater than 145,000 g / mol, greater than 150,000 g / mol, greater than 155,000 g / mol, greater than 160,000 g / mol, greater than 165,000 g / mol, greater than 170,000 g / mol, greater than 175,000 g / mol, greater than 180,000 g / mol, greater than 185,000 g / mol, greater than 190,000 g / mol, or greater than 195,000 g / mol.

[0154] In some embodiments, the number average molecular weight of the binder composition is from about 10,000 g / mol to about 100,000 g / mol, from about 15,000 g / mol to about 100,000 g / mol, from about 20,000 g / mol to about 100,000 g / mol, from about 25,000 g / mol to about 100,000 g / mol, from about 30,000 g / mol to about 100,000 g / mol, from about 35,000 g / mol to about 100,000 g / mol, from about 40,000 g / mol to about 100,000 g / mol, or from about 45,000 g / mol to about 100,000 g / mol. mol, about 50,000 g / mol to about 100,000 g / mol, about 50,000 g / mol to about 95,000 g / mol, about 50,000 g / mol to about 90,000 g / mol, about 50,000 g / mol to about 85,000 g / mol, about 50,000 g / mol to about 80,000 g / mol, about 55,000 g / mol to about 80,000 g / mol, about 60,000 g / mol to about 80,000 g / mol, about 65,000 g / mol to about 75,000 g / mol, or about 60,000 g / mol to about 90,000 g / mol.

[0155] In some embodiments, the number average molecular weight of the binder composition is less than 100,000 g / mol, less than 95,000 g / mol, less than 90,000 g / mol, less than 85,000 g / mol, less than 80,000 g / mol, less than 75,000 g / mol, less than 70,000 g / mol, less than 65,000 g / mol, less than 60,000 g / mol, less than 55,000 g / mol, less than 50,000 g / mol, less than 45,000 g / mol, less than 40,000 g / mol, less than 35,000 g / mol, less than 30,000 g / mol, less than 25,000 g / mol, less than 20,000 g / mol, or less than 15,000 g / mol. In some embodiments, the number average molecular weight of the binder composition is greater than 10,000 g / mol, greater than 15,000 g / mol, greater than 20,000 g / mol, greater than 25,000 g / mol, greater than 30,000 g / mol, greater than 35,000 g / mol, greater than 40,000 g / mol, greater than 45,000 g / mol, greater than 50,000 g / mol, greater than 55,000 g / mol, greater than 60,000 g / mol, greater than 65,000 g / mol, greater than 70,000 g / mol, greater than 75,000 g / mol, greater than 80,000 g / mol, greater than 85,000 g / mol, greater than 90,000 g / mol, or greater than 95,000 g / mol.

[0156] In some embodiments, the polydispersity index (PDI) of the binder composition is from about 1 to about 5, from about 1 to about 4.8, from about 1 to about 4.6, from about 1 to about 4.4, from about 1 to about 4.2, from about 1 to about 4, from about 1 to about 3.8, from about 1 to about 3.6, from about 1 to about 3.4, from about 1 to about 3.2, from about 1 to about 3, from about 1.1 to about 3, from about 1.2 to about 3, from about 1.3 to about 3, from about 1.4 to about 3, from about 1.5 to about 3, from about 1.6 to about 3, from about 1.6 to about 2.8, from about 1.6 to about 2.6, from about 1.8 to about 2.6, or from about 1.8 to about 2.8. When the polydispersity index of the binder composition is within the above range, the stability of the binder composition can be further improved.

[0157] In some embodiments, the polydispersity index of the binder composition is less than 5, less than 4.8, less than 4.6, less than 4.4, less than 4.2, less than 4, less than 3.8, less than 3.6, less than 3.4, less than 3.2, less than 3, less than 2.8, less than 2.6, less than 2.4, less than 2.2, less than 2, less than 1.8, less than 1.6, less than 1.4, or less than 1.2. In some embodiments, the polydispersity index of the binder composition is greater than 1, greater than 1.2, greater than 1.4, greater than 1.6, greater than 1.8, greater than 2, greater than 2.2, greater than 2.4, greater than 2.6, greater than 2.8, greater than 3, greater than 3.2, greater than 3.4, greater than 3.6, greater than 3.8, greater than 4, greater than 4.2, greater than 4.4, greater than 4.6, or greater than 4.8.

[0158] The binder composition of the present invention exhibits strong adhesive strength to a current collector. It is important for the binder composition to have good adhesive strength to a current collector in the production of a battery electrode, because it promotes the bonding strength of the electrode layer to the current collector, prevents separation, and improves the mechanical stability of the electrode. In some embodiments, the adhesive strength between the binder composition and the current collector is about 2 N / cm to about 4 N / cm, about 2.1 N / cm to about 4 N / cm, about 2.2 N / cm to about 4 N / cm, about 2.3 N / cm to about 4 N / cm, about 2.4 N / cm to about 4 N / cm, about 2.5 N / cm to about 4 N / cm, about 2.6 N / cm to about 4 N / cm, about 2.7 N / cm to about 4 N / cm, about 2.8 N / cm to about 4 N / cm, about 2.9 N / cm to about 4 N / cm, about 3 N / cm to about 4 N / cm, or about 2 N / cm to about 3.9 N / cm. N / cm, about 2N / cm to about 3.8N / cm, about 2N / cm to about 3.7N / cm, about 2N / cm to about 3.6N / cm, about 2N / cm to about 3.5N / cm, about 2N / cm to about 3.4N / cm, about 2N / cm to about 3.3N / cm, about 2N / cm to about 3.2N / cm, about 2N / cm to about 3.1N / cm, about 2N / cm to about 3N / cm, about 2.5N / cm to about 3.5N / cm, about 2.3N / cm to about 3.7N / cm, about 2.5N / cm to about 3N / cm, or about 3N / cm to about 3.5N / cm.

[0159] In some embodiments, the adhesive strength between the binder composition and the current collector is less than 4 N / cm, less than 3.9 N / cm, less than 3.8 N / cm, less than 3.7 N / cm, less than 3.6 N / cm, less than 3.5 N / cm, less than 3.4 N / cm, less than 3.3 N / cm, less than 3.2 N / cm, less than 3.1 N / cm, less than 3 N / cm, less than 2.9 N / cm, less than 2.8 N / cm, less than 2.7 N / cm, less than 2.6 N / cm, less than 2.5 N / cm, less than 2.4 N / cm, less than 2.3 N / cm, or less than 2.2 N / cm. In some embodiments, the adhesive strength between the binder composition and the current collector is greater than 2 N / cm, greater than 2.1 N / cm, greater than 2.2 N / cm, greater than 2.3 N / cm, greater than 2.4 N / cm, greater than 2.5 N / cm, greater than 2.6 N / cm, greater than 2.7 N / cm, greater than 2.8 N / cm, greater than 2.9 N / cm, greater than 3 N / cm, greater than 3.1 N / cm, greater than 3.2 N / cm, greater than 3.3 N / cm, greater than 3.4 N / cm, greater than 3.5 N / cm, greater than 3.6 N / cm, greater than 3.7 N / cm, or greater than 3.8 N / cm.

[0160] In another aspect, provided herein is an electrode for a secondary battery, comprising an electrode active material, a current collector, and a binder composition prepared by the method described above. In other embodiments, the electrode further comprises a conductive agent.

[0161] In some embodiments, the electrode active material is a cathode active material, and the cathode active material is LiCoO2, LiNiO2, LiNi x Mn y O2, Li 1+z Ni x Mn y Co 1-x-y O2, LiNi x Co y Al zIn certain embodiments, the cathode active material is selected from the group consisting of LiCoO2, LiNi ... x Mn y O2, Li 1+z Ni x Mn y Co 1-x-y O2(NMC), LiNi x Co y Al z In another embodiment, the cathode active material is selected from the group consisting of LiCoO2, LiNiO2, LiV2O5, LiTiS2, LiMoS2, LiMnO2, LiCrO2, LiMn2O4, LiFeO2, LiFePO4, and combinations thereof, where each x is independently 0.4 to 0.6, each y is independently 0.2 to 0.4, and each z is independently 0 to 0.1. In another embodiment, the cathode active material is not LiCoO2, LiNiO2, LiV2O5, LiTiS2, LiMoS2, LiMnO2, LiCrO2, LiMn2O4, LiFeO2, or LiFePO4. In a further embodiment, the cathode active material is LiNi x Mn y O2, Li 1+z Ni x Mn y Co 1-x-y O2 or LiNi x Co y Al z each x is independently 0.2 to 0.9, each y is independently 0.1 to 0.45, and each z is independently 0 to 0.2. In certain embodiments, the cathode active material is Li 1+x Ni a Mn b Co c Al (1-a-b-c) O2, where -0.2≦x≦0.2, 0≦a<1, 0≦b<1, 0≦c<1, and a+b+c≦1. In some embodiments, the cathode active material is represented by the general formula Li 1+x Ni a Mnb Co c Al (1-a-b-c) O2, wherein 0.33≦a≦0.92, 0.33≦a≦0.9, 0.33≦a≦0.8, 0.5≦a≦0.92, 0.5≦a≦0.9, 0.5≦a≦0.8, 0.6≦a≦0.92, or 0.6≦a≦0.9; 0≦b≦0.5, 0≦b≦0.3, 0.1≦b≦0.5, 0.1≦b≦0.4, 0.1≦b≦0.3, 0.1≦b≦0.2, or 0.2≦b≦0.5; 0≦c≦0.5, 0≦c≦0.3, 0.1≦c≦0.5, 0.1≦c≦0.4, 0.1≦c≦0.3, 0.1≦c≦0.2, or 0.2≦c≦0.5.

[0162] In certain embodiments, the cathode active material is doped with a dopant selected from the group consisting of Fe, Ni, Mn, Al, Mg, Zn, Ti, La, Ce, Sn, Zr, Ru, Si, Ge, and combinations thereof. In some embodiments, the dopant is not Fe, Ni, Mn, Mg, Zn, Ti, La, Ce, Ru, Si, or Ge. In certain embodiments, the dopant is not Al, Sn, or Zr.

[0163] In some embodiments, the cathode active material is LiNi 0.33 Mn 0.33 Co 0.33 O2(NMC333), LiNi 0.4 Mn 0.4 Co 0.2 O2, LiNi 0.5 Mn 0.3 Co 0.2 O2(NMC532), LiNi 0.6 Mn 0.2 Co 0.2 O2(NMC622), LiNi 0.7 Mn 0.15 Co 0.15 O2, LiNi 0.8 Mn 0.1 Co 0.1 O2(NMC811), LiNi 0.92 Mn 0.04 Co 0.04 O2, LiNi 0.8 Co 0.15 Al 0.05O2 (NCA), LiNiO2 (LNO) and combinations thereof.

[0164] In other embodiments, the cathode active material is not LiCoO2, LiNiO2, LiMnO2, LiMn2O4, or Li2MnO3. In further embodiments, the cathode active material is LiNi 0.33 Mn 0.33 Co 0.33 O2, LiNi 0.4 Mn 0.4 Co 0.2 O2, LiNi 0.5 Mn 0.3 Co 0.2 O2, LiNi 0.6 Mn 0.2 Co 0.2 O2, LiNi 0.7 Mn 0.15 Co 0.15 O2, LiNi 0.8 Mn 0.1 Co 0.1 O2, LiNi 0.92 Mn 0.04 Co 0.04 O2 or LiNi 0.8 Co 0.15 Al 0.05 Not O2.

[0165] In certain embodiments, the cathode active material comprises or is a core-shell composite having a core and a shell structure, wherein the core and shell are each independently Li 1+x Ni a Mn b Co c Al (1-a-b-c) O2, LiCoO2, LiNiO2, LiMnO2, LiMn2O4, Li2MnO3, LiCrO2, Li4Ti5O 12 , LiV2O5, LiTiS2, LiMoS 2、and combinations thereof, where -0.2≦x≦0.2, 0≦a<1, 0≦b<1, 0≦c<1, and a+b+c≦1. In other embodiments, the core and shell each independently comprise two or more lithium transition metal oxides. In some embodiments, one of the core or shell comprises only one lithium transition metal oxide, and the other comprises two or more lithium transition metal oxides. The lithium transition metal oxide or oxides of the core and shell may be the same, or they may be different or partially different. In some embodiments, the two or more lithium transition metal oxides are uniformly distributed on the core. In certain embodiments, the two or more lithium transition metal oxides are not uniformly distributed on the core. In some embodiments, the cathode active material is not a core-shell composite.

[0166] In some embodiments, each of the core and shell lithium transition metal oxides is independently doped with a dopant selected from the group consisting of Fe, Ni, Mn, Al, Mg, Zn, Ti, La, Ce, Sn, Zr, Ru, Si, Ge, and combinations thereof. In certain embodiments, the core and shell each independently comprise two or more doped lithium transition metal oxides. In certain embodiments, the two or more doped lithium transition metal oxides are uniformly distributed on the core and / or shell. In certain embodiments, the two or more doped lithium transition metal oxides are not uniformly distributed on the core and / or shell.

[0167] In some embodiments, the cathode active material comprises or is a core-shell composite comprising a core comprising a lithium transition metal oxide and a shell comprising a transition metal oxide. In certain embodiments, the lithium transition metal oxide is Li 1+x Ni a Mn b Co c Al (1-a-b-c)O2, LiCoO2, LiNiO2, LiMnO2, LiMn2O4, Li2MnO3, LiCrO2, Li4Ti5O 12 , LiV2O5, LiTiS2, LiMoS2, and combinations thereof, where -0.2≦x≦0.2, 0≦a<1, 0≦b<1, 0≦c<1, and a+b+c≦1. In some embodiments, the transition metal oxide is selected from the group consisting of Fe2O3, MnO2, Al2O3, MgO, ZnO, TiO2, La2O3, CeO2, SnO2, ZrO2, RuO2, and combinations thereof. In certain embodiments, the shell comprises a lithium transition metal oxide and a transition metal oxide.

[0168] In some embodiments, the core diameter is about 1 μm to about 15 μm, about 3 μm to about 15 μm, about 3 μm to about 10 μm, about 5 μm to about 10 μm, about 5 μm to about 45 μm, about 5 μm to about 35 μm, about 5 μm to about 25 μm, about 10 μm to about 45 μm, about 10 μm to about 40 μm, or about 10 μm to about 35 μm, about 10 μm to about 25 μm, about 15 μm to about 45 μm, about 15 μm to about 30 μm, about 15 μm to about 25 μm, about 20 μm to about 35 μm, or about 20 μm to about 30 μm. In certain embodiments, the shell thickness is about 1 μm to about 45 μm, about 1 μm to about 35 μm, about 1 μm to about 25 μm, about 1 μm to about 15 μm, about 1 μm to about 10 μm, about 1 μm to about 5 μm, about 3 μm to about 15 μm, about 3 μm to about 10 μm, about 5 μm to about 10 μm, about 10 μm to about 35 μm, about 10 μm to about 20 μm, about 15 μm to about 30 μm, about 15 μm to about 25 μm, or about 20 μm to about 35 μm. In certain embodiments, the ratio of the diameter or thickness of the core to the shell is 15:85 to 85:15, 25:75 to 75:25, 30:70 to 70:30, or 40:60 to 60:40. In certain embodiments, the volume or weight ratio of core to shell is 95:5, 90:10, 80:20, 70:30, 60:40, 50:50, 40:60, or 30:70.

[0169] The current collector functions to collect electrons generated by the electrochemical reaction of the cathode active material or to supply electrons required for the electrochemical reaction. In some embodiments, the current collector can be in the form of a foil, sheet, or film. In certain embodiments, the current collector is stainless steel, titanium, nickel, aluminum, copper, or an alloy thereof, or an electrically conductive resin. In certain embodiments, the current collector has a two-layer structure including an outer layer and an inner layer, where the outer layer comprises a conductive material and the inner layer comprises an insulating material or another conductive material, for example, aluminum attached with a conductive resin layer or a polymer insulating material coated with an aluminum film. In some embodiments, the current collector has a three-layer structure including an outer layer, an intermediate layer, and an inner layer, where the outer layer and the inner layer comprise a conductive material and the intermediate layer comprises an insulating material or another conductive material, for example, a plastic substrate coated with a metal film on both sides. In certain embodiments, the outer layer, the intermediate layer, and the inner layer are each independently stainless steel, titanium, nickel, aluminum, copper, or an alloy thereof, or a conductive resin. In some embodiments, the insulating material is a polymeric material selected from the group consisting of polycarbonate, polyacrylate, polyacrylonitrile, polyester, polyamide, polystyrene, polyurethane, polyepoxy, poly(acrylonitrile butadiene styrene), polyimide, polyolefin, polyethylene, polypropylene, polyphenylene sulfide, poly(vinyl ester), polyvinyl chloride, polyether, polyphenyl oxide, cellulose polymer, and combinations thereof. In certain embodiments, the current collector has three or more layers. In some embodiments, the current collector is coated with a protective coating. In certain embodiments, the protective coating comprises a carbon-containing material. In some embodiments, the current collector is not coated with a protective coating.

[0170] The thickness of the current collector affects the volume it occupies in the battery, the amount of electrode active material required, and the capacity of the battery. In some embodiments, the current collector has a thickness of about 5 μm to about 30 μm. In specific embodiments, the current collector has a thickness of about 5 μm to about 20 μm, about 5 μm to about 15 μm, about 10 μm to about 30 μm, about 10 μm to about 25 μm, or about 10 μm to about 20 μm.

[0171] In some embodiments, the current collector has a thickness of less than 30 μm, less than 28 μm, less than 26 μm, less than 24 μm, less than 22 μm, less than 20 μm, less than 18 μm, less than 16 μm, less than 14 μm, less than 12 μm, less than 10 μm, less than 8 μm, or 6 μm. In some embodiments, the current collector has a thickness of more than 5 μm, more than 7 μm, more than 10 μm, more than 12 μm, more than 14 μm, more than 16 μm, more than 18 μm, more than 20 μm, more than 22 μm, more than 24 μm, more than 26 μm, or more than 28 μm.

[0172] The conductive agent is intended to improve the electrical conductivity of the electrode. Any suitable material can act as the conductive agent. In some embodiments, the conductive agent is a carbonaceous material. Some non-limiting examples include carbon, carbon black, graphite, expanded graphite, graphene, graphene nanoplatelets, carbon fiber, carbon nanofiber, graphitized carbon flakes, carbon tubes, activated carbon, Super P, zero-dimensional KS6, one-dimensional vapor-grown carbon fiber (VGCF), mesoporous carbon, and combinations thereof.

[0173] Furthermore, cathodes prepared using the binder composition of the present invention exhibit strong adhesion between the electrode layer and the current collector. Having good peel strength between the electrode layer and the current collector is important for preventing electrode peeling or separation, which significantly affects the mechanical stability of the electrode and the cycleability of the battery. Therefore, the electrode must have sufficient peel strength to withstand the rigors of battery manufacturing.

[0174] In some embodiments, the peel strength between the current collector and the electrode layer is about 1.0 N / cm to about 8.0 N / cm, about 1.0 N / cm to about 6.0 N / cm, about 1.0 N / cm to about 5.0 N / cm, about 1.0 N / cm to about 4.0 N / cm, about 1.0 N / cm to about 3.0 N / cm, about 1.0 N / cm to about 2.5 N / cm, about 1.0 N / cm to about 2.0 N / cm, about 1.2 N / cm to about 3.0 N / cm, about 1.2 N / cm to about 2.5 N / cm, about 1.2 N / cm to about 2.0 N / cm, about 1.5 N / cm to about 3.0 N / cm, or 1.5 N / cm to about 2.5 N / cm, 1.5 N / cm to about 2.0 N / cm, 1.8 N / cm to about 3.0 N / cm, 1.8 N / cm to about 2.5 N / cm, 2.0 N / cm to about 6.0 N / cm, 2.0 N / cm to about 5.0 N / cm, about 2.0 N / cm to about 3.0 N / cm, about 2.0 N / cm to about 2.5 N / cm, about 2.2 N / cm to about 3.0 N / cm, about 2.5 N / cm to about 3.0 N / cm, about 3.0 N / cm to about 8.0 N / cm, about 3.0 N / cm to about 6.0 N / cm, or about 4.0 N / cm to about 6.0 N / cm.

[0175] In some embodiments, the peel strength between the current collector and the electrode layer is 1.0 N / cm or more, 1.2 N / cm or more, 1.5 N / cm or more, 2.0 N / cm or more, 2.2 N / cm or more, 2.5 N / cm or more, 3.0 N / cm or more, 3.5 N / cm or more, 4.5 N / cm or more, 5.0 N / cm or more, 5.5 N / cm or more. In some embodiments, the peel strength between the current collector and the electrode layer is less than 6.5 N / cm, less than 6.0 N / cm, less than 5.5 N / cm, less than 5.0 N / cm, less than 4.5 N / cm, less than 4.0 N / cm, less than 3.5 N / cm, less than 3.0 N / cm, less than 2.8 N / cm, less than 2.5 N / cm, less than 2.2 N / cm, less than 2.0 N / cm, less than 1.8 N / cm, or less than 1.5 N / cm.

[0176] The degree of swelling of a binder composition due to electrolyte uptake in a secondary battery provides insight into the crystallinity of the binder composition, how the binder composition interacts with the electrolyte, and the flexibility of the binder composition. On the other hand, binder compositions with high crystallinity exhibit low swelling behavior, which can create a barrier to solvent penetration, shorten ion transport paths, lower internal resistance, and, more importantly, alter the mechanical properties of the swollen polymer, which are essential for stable battery performance. On the other hand, binder compositions with low crystallinity have more amorphous regions, which allow more electrolyte to penetrate the binder composition and ensure good ion transport without decomposition of the binder composition when subjected to swelling. The semi-crystalline binder compositions disclosed herein benefit from both influencing factors and therefore exhibit superior electrochemical performance.

[0177] In some embodiments, the electrolyte swelling of the binder composition is between about 7% and about 10%, between about 7% and about 9.9%, between about 7% and about 9.8%, between about 7% and about 9.7%, between about 7% and about 9.6%, between about 7% and about 9.5%, between about 7% and about 9.4%, between about 7% and about 9.3%, between about 7% and about 9.2%, between about 7% and about 9.1%, between about 7% and about 9%, between about 7% and about 8.9%, between about 7% and about 8.8%, between about 7% and about 8.7%, between about 7% and about 8.6%, between about 7% and about 8.5%, between about 7% and about 8. 0.4%, about 7% to about 8.3%, about 7% to about 8.2%, about 7% to about 8.1%, about 7% to about 8%, about 7.1 to about 10%, about 7.2% to about 10%, about 7.3% to about 10%, about 7.4% to about 10%, about 7.5% to about 10%, about 7.6% to about 10%, about 7.7% to about 10%, about 7.8% to about 10%, about 7.9% to about 10%, about 8% to about 10%, about 7.5% to about 9.5%, about 7.5% to about 9%, about 8% to about 9%, or about 8% to about 9.5%.

[0178] In some embodiments, the electrolyte swelling of the binder composition is less than 10%, less than 9.9%, less than 9.8%, less than 9.7%, less than 9.6%, less than 9.5%, less than 9.4%, less than 9.3%, less than 9.2%, less than 9.1%, less than 9%, less than 8.9%, less than 8.8%, less than 8.7%, less than 8.6%, less than 8.5%, less than 8.4%, less than 8.3%, less than 8.2%, less than 8.1%, less than 8%, less than 7.9%, less than 7.8%, less than 7.7%, less than 7.6%, less than 7.5%, less than 7.4%, less than 7.3%, less than 7.2%, or less than 7.1%. In some embodiments, the electrolyte swelling of the binder composition is greater than 7%, greater than 7.1%, greater than 7.2%, greater than 7.3%, greater than 7.4%, greater than 7.5%, greater than 7.6%, greater than 7.7%, greater than 7.8%, greater than 7.9%, greater than 8%, greater than 8.1%, greater than 8.2%, greater than 8.3%, greater than 8.4%, greater than 8.5%, greater than 8.6%, greater than 8.7%, greater than 8.8%, greater than 8.9%, greater than 9%, greater than 9.1%, greater than 9.2%, greater than 9.3%, greater than 9.4%, greater than 9.5%, greater than 9.6%, greater than 9.7%, greater than 9.8%, or greater than 9.9%.

[0179] The method disclosed herein has the advantages of being able to use aqueous solvents in the manufacturing process, thereby saving processing time and equipment, and improving safety by eliminating the need to handle and recycle hazardous organic solvents. Furthermore, the overall process is simplified, reducing costs. Therefore, the method is particularly suitable for industrial processes due to its low cost and ease of handling.

[0180] The following examples are presented to illustrate embodiments of the present invention, but are not intended to limit the invention to the specific embodiments set forth. Unless otherwise indicated, all parts and percentages are by weight. All numerical values are approximate. When numerical ranges are given, it should be understood that embodiments outside the stated ranges may still fall within the scope of the invention. The specific details set forth in each example should not be construed as necessary features of the invention. Example

[0181] The pH value of the binder composition was measured using an electrode type pH meter (ION2700, manufactured by Eutec Instruments).

[0182] The viscosity of the binder composition was measured at 25°C using a rotational viscometer (NDJ-5S, Shanghai JT Electronics Technology Co., Ltd., China).

[0183] The adhesive strength of the dried binder composition layer was measured using a tensile tester (DZ-106A, Dongguan Zhonghou Testing Equipment Co., Ltd., China). This test measures the average force, in Newtons, required to peel the binder composition layer from the current collector at an angle of 180°. The average roughness depth (Rz) of the current collector was 2 μm. The binder composition was applied to the current collector and dried to obtain a binder composition layer with a thickness of 10 μm to 12 μm. The applied current collector was then placed in a constant temperature environment of 25°C and 50% to 60% humidity for 30 minutes. A strip of adhesive tape (3M; USA, Model No. 810) measuring 18 mm wide and 20 mm long was attached to the surface of the binder composition layer. The binder composition strip was clamped in the tester, and the tape was folded back 180° onto itself, placed in the movable jaw, and pulled at room temperature at a peeling rate of 300 mm per minute. The maximum peel force measured was taken as the adhesive strength. The measurement was repeated three times and the average value was calculated.

[0184] The electrolyte swelling of the binder composition was measured by measuring the mass change of the binder composition before and after immersion in an electrolyte. A dried binder composition strip test piece measuring 50 to 60 mm in length and 1 mm in width was prepared. This dried binder composition strip was further dried at 80°C for 1 to 2 hours to completely remove moisture from the strip. The weight of the dried binder composition strip was measured, and after cooling, it was placed in a sealed container together with an electrolyte. The binder composition strip was immersed in an electrolyte at 25°C for 3 days. After removing the binder composition strip from the container containing the electrolyte, the electrolyte on the strip surface was absorbed with oil-absorbent paper. The weight of the immersed binder composition strip was measured. The ratio of the weight change of the strip before and after immersion in the electrolyte to the weight of the strip before immersion in the electrolyte was defined as electrolyte swelling. The measurement was repeated three times, and the average value was calculated.

[0185] The solid content of the binder composition was measured by measuring the mass change of the binder composition before and after drying. Approximately 1 g of the binder composition was weighed into a weighing bottle and dried in a vacuum dryer at 110±5°C and -0.09 MPa for more than 5 hours. The binder composition was cooled in a desiccator for approximately 15 minutes and then its mass was measured. The difference in mass of the binder composition before and after drying was determined, and the solid content (%) of the binder composition was calculated using the following formula.

[0186]

number

[0187] The weight-average molecular weight and number-average molecular weight of the binder composition were measured by gel permeation chromatography (GPC). First, the binder composition was dissolved in dimethylformamide at room temperature. Once the binder composition was completely dissolved, the solution was gently filtered through a 0.45 μm filter to prepare a measurement sample. A calibration curve was created using standard polystyrene so that the weight-average molecular weight and number-average molecular weight could be calculated as standard equivalent values. The molecular weight distribution in the binder composition is expressed by the polydispersity index (PDI), which is the ratio of the weight-average molecular weight to the number-average molecular weight. The obtained measurement sample was analyzed under the following conditions.

[0188] Column: Agilent PLgel 5um MIXED-C column

[0189] Eluent: dimethylformamide

[0190] Flow rate: 1ml / min

[0191] Sample weight: 2 mg

[0192] Detector: Waters 2414 refractive index (RI) detector

[0193] Detection temperature: 35℃

[0194] Standard material: polystyrene Example 1 A) Preparation of the binder composition

[0195] 80 g of a neutralizing agent (sodium hydroxide, NaOH) was added to a round-bottom flask containing 1500 g of distilled water, and the mixture was stirred at 80 rpm for 30 minutes to obtain a first suspension.

[0196] 180 g of acrylic acid (AA) was dissolved in 200 g of purified water to form an AA solution. Then, 380 g of the AA solution was added to the first suspension. This mixture was further stirred at 80 rpm for 30 minutes to obtain a second suspension.

[0197] 94 g of acrylamide (AM) was dissolved in 200 g of purified water to form an AM solution. Then, 294 g of the AM solution was added to the second suspension. This mixture was further heated to 55°C and stirred at 80 rpm for 45 minutes to obtain a third suspension.

[0198] 66 g of acrylonitrile (AN) was dissolved in 50 g of purified water to form an AN solution. Then, 116 g of the AN solution was added to the third suspension. This mixture was further stirred at 80 rpm and 55°C for 10 minutes to obtain a fourth suspension.

[0199] Furthermore, 0.075 g of a water-soluble free radical initiator (ammonium persulfate, APS; obtained from Aladdin Industrial Co., Ltd., China) was dissolved in 15 g of purified water, and 0.0375 g of a reducing agent (sodium bisulfite; obtained from Tianjin Cannabis Chemical Reagent Factory, China) was dissolved in 7.5 g of purified water. 15.075 g of the APS solution and 7.5375 g of the sodium bisulfite solution were added to the fourth suspension. This mixture was stirred at 200 rpm and 55°C for 24 hours to obtain the fifth suspension.

[0200] After the reaction was completed, the temperature of the fifth suspension was lowered to 25°C. 19.12 g of NaOH was dissolved in 3,300 g of pure water. Then, 3,319.12 g of sodium hydroxide solution was added dropwise to the fifth suspension over one hour to adjust the pH to 7.59, forming a sixth suspension. The binder composition was filtered using a 200-mesh filter paper to prepare a binder composition. The binder composition had a solids content of 6.77 wt.%. The binder composition had a weight-average molecular weight of 125,031 g / mol, a number-average molecular weight of 55,437 g / mol, and a polydispersity index of 2.26. The components and their respective blending ratios of the binder composition of Example 1 are shown in Table 1 below. The pH, solids content, viscosity, adhesive strength, and electrolyte swelling of the binder composition of Example 1 were also measured and are shown in Table 2 below. B) Preparation of the positive electrode

[0201] A first mixture was prepared by dispersing 0.9 g of a conductive agent (SuperP; available from Timcal Ltd, Bodio, Switzerland) and 6 g of a binder composition (solid content 6.77 wt.%) in deionized water while stirring with an overhead stirrer (R20, manufactured by IKA). After addition, the first mixture was further stirred at 25°C and 1200 rpm for approximately 30 minutes.

[0202] Then, 28.2 g of NMC622 (Shandong Tianqiao New Energy Co., Ltd., China) was added to the first mixture at 25°C while stirring with an overhead stirrer to prepare a second mixture. The second mixture was then degassed for 1 hour under a pressure of approximately 10 kPa. The second mixture was then further stirred at 25°C for approximately 60 minutes at 1,200 rpm to form a homogenized slurry.

[0203] This homogenized slurry was applied to one side of a 14 μm thick aluminum foil current collector using a doctor blade coater. The slurry film applied to the aluminum foil was dried at approximately 85 °C for 120 minutes in a hot air dryer (DHG 10H, Huyue Equipment Co. Ltd., China) to form a cathode electrode layer. The electrode was then pressed to reduce the thickness of the cathode electrode layer to 27 μm and the surface density to 5.2 mg / cm. 2 It was. C) Preparation of the negative electrode

[0204] Anode slurry was prepared by mixing 90 wt.% hard carbon (BTR New Energy Materials Inc., Shenzhen, Guangdong Province, China), 1.5 wt.% carboxymethyl cellulose (CMC, BSH-12, DKS Corporation, Japan), 3.5 wt.% SBR (AL-2001, Nippon A&L Co., Ltd., Japan) as a binder, and 5 wt.% carbon black as a conductive agent in deionized water. The solids content of the anode slurry was 50 wt.%. This slurry was applied to one side of an 8 μm-thick copper foil using a doctor blade coater. The coating on the copper foil was dried in a hot air dryer at approximately 85 °C for 120 minutes to obtain the anode. The electrode was then pressed to reduce the coating thickness to 18 μm. D) Coin Cell Assembly

[0205] CR2032 coin-type Li batteries were assembled in an argon-filled glove box. The coated cathode and anode plates were cut into disc-shaped positive and negative electrodes. The cathode and anode plates were alternately stacked to form an electrode assembly, which was then housed in a CR2032-type stainless steel case. The cathode and anode electrodes were separated by a separator. The separator was a ceramic-coated nonwoven microporous membrane (MPM, Japan) with a thickness of approximately 25 μm. The electrode assembly was then dried at 105 °C for approximately 16 h under vacuum in a box-type resistance oven (DZF-6020, Shenzhen Kejing Star Technology Co., Ltd., China).

[0206] Next, the electrolyte was poured into the case holding the filled electrodes under a high-purity argon atmosphere with moisture and oxygen levels below 3 ppm. The electrolyte was a solution of LiPF6 (1M) mixed with ethylene carbonate (EC), ethyl methyl carbonate (EMC), and dimethyl carbonate (DMC) in a volume ratio of 1:1:1. After filling with the electrolyte, the coin cell was vacuum-sealed and mechanically pressed using a standard circular punch die. E) Electrochemical measurements

[0207] The coin battery was analyzed in constant current mode using a multi-channel battery tester (BTS-4008-5V10mA, obtained from Neware Electronics Co., Ltd., China). After completing one cycle at C / 20, it was charged and discharged at a rate of C / 2. The cell was subjected to a charge-discharge cycle test under conditions of 3.0-4.3V, a current density of C / 2, and 25°C, and the discharge capacity was determined. The electrochemical performance of the coin battery of Example 1 was measured and is shown in Table 2 below. Preparation of Binder Composition of Example 2

[0208] 16 g of NaOH was added to a round-bottom flask containing 380 g of distilled water, and the mixture was stirred at 80 rpm for 30 minutes to obtain a first suspension.

[0209] 35.80 g of AA was added to the first suspension, and the mixture was further stirred at 80 rpm for 30 minutes to obtain a second suspension.

[0210] 18.70 g of AM was dissolved in 10 g of purified water to form an AM solution. Then, 28.70 g of the AM solution was added to the second suspension. This mixture was further heated to 55°C and stirred at 80 rpm for 45 minutes to obtain a third suspension.

[0211] 13.50 g of AN was added to the third suspension, and the mixture was further stirred at 80 rpm for 10 minutes to obtain a fourth suspension.

[0212] Furthermore, 0.015 g of APS was dissolved in 3 g of purified water, and 0.0075 g of sodium bisulfite was dissolved in 1.5 g of purified water. 3.015 g of the APS solution and 1.5075 g of the sodium bisulfite solution were added to the fourth suspension. This mixture was stirred at 200 rpm at 55°C for 24 hours to obtain the fifth suspension.

[0213] After the reaction was completed, the temperature of the fifth suspension was lowered to 25°C. 3.72 g of NaOH was dissolved in 400 g of pure water. 403.72 g of sodium hydroxide solution was then added dropwise to the fifth suspension over 1 hour to adjust the pH to 7.31, forming a sixth suspension. The binder composition was then filtered using a 200-mesh filter paper. The solids content of the binder composition was 9.00 wt.%.

[0214] Example 3: A binder composition was prepared in the same manner as in Example 2, except that 36.04 g of AA was added in the preparation of the second suspension, 17.0 g of AM was added in the preparation of the third suspension, and 14.96 g of AN was added in the preparation of the fourth suspension.

[0215] Example 4: A binder composition was prepared in the same manner as in Example 2, except that 37.4 g of AA was added in the preparation of the second suspension, 17.0 g of AM was added in the preparation of the third suspension, and 13.6 g of AN was added in the preparation of the fourth suspension.

[0216] Example 5: A binder composition was prepared in the same manner as in Example 2, except that 40.8 g of AA was added in the preparation of the second suspension, 17.0 g of AM was added in the preparation of the third suspension, 10.2 g of AN was added in the preparation of the fourth suspension, and 5.33 g of NaOH was added in the preparation of the sixth suspension.

[0217] Example 6: A binder composition was prepared in the same manner as in Example 2, except that 44.2 g of AA was added in the preparation of the second suspension, 17.0 g of AM was added in the preparation of the third suspension, 6.8 g of AN was added in the preparation of the fourth suspension, and 6.23 g of NaOH was added in the preparation of the sixth suspension.

[0218] Example 7: A binder composition was prepared in the same manner as in Example 2, except that 47.6 g of AA was added in the preparation of the second suspension, 10.2 g of AM was added in the preparation of the third suspension, 10.2 g of AN was added in the preparation of the fourth suspension, and 8.18 g of NaOH was added in the preparation of the sixth suspension.

[0219] Example 8: A binder composition was prepared in the same manner as in Example 2, except that 28.56 g of AA was added in the preparation of the second suspension, 23.12 g of AM was added in the preparation of the third suspension, and 16.32 g of AN was added in the preparation of the fourth suspension.

[0220] Example 9: A binder composition was prepared in the same manner as in Example 2, except that 34.0 g of AA was added in the preparation of the second suspension, 23.8 g of AM was added in the preparation of the third suspension, and 10.2 g of AN was added in the preparation of the fourth suspension.

[0221] Example 10: A binder composition was prepared in the same manner as in Example 2, except that in preparing the sixth suspension, 9.50 g of NaOH was added to the fifth suspension to adjust the pH to 8.23.

[0222] Example 11: A binder composition was prepared in the same manner as in Example 2, except that in the preparation of the sixth suspension, 10.93 g of NaOH was added to the fifth suspension to adjust the pH to 8.51. Preparation of binder compositions of Examples 12 to 14

[0223] The binder compositions of Examples 12 to 14 were prepared in the same manner as in Example 2.

[0224] Example 15: A binder composition was prepared in the same manner as in Example 2, except that in the preparation of the fifth suspension, 0.0204 g of APS was dissolved in 3 g of pure water and 0.0102 g of sodium bisulfite was dissolved in 1.5 g of pure water, so that 3.0204 g of APS solution and 1.5102 g of sodium bisulfite solution were added. The binder composition had a weight-average molecular weight of 78,528 g / mol, a number-average molecular weight of 33,523 g / mol, and a polydispersity index of 2.34.

[0225] Example 16: A binder composition was prepared in the same manner as in Example 2, except that in the preparation of the fifth suspension, 0.0068 g of APS was dissolved in 3 g of pure water and 0.0034 g of sodium bisulfite was dissolved in 1.5 g of pure water, so that 3.0068 g of APS solution and 1.5034 g of sodium bisulfite solution were added. The binder composition had a weight-average molecular weight of 175,432 g / mol, a number-average molecular weight of 82,640 g / mol, and a polydispersity index of 2.12. Comparative Example 1

[0226] Binder compositions were prepared in the same manner as in Example 2, except that 30.6 g of AA was added in the preparation of the second suspension, 10.2 g of AM was added in the preparation of the third suspension, and 27.2 g of AN was added in the preparation of the fourth suspension. Comparative Example 2

[0227] The binder compositions were prepared in the same manner as in Example 2, except that 44.2 g of AA was added in the preparation of the second suspension, 20.4 g of AM was added in the preparation of the third suspension, 3.4 g of AN was added in the preparation of the fourth suspension, and 6.5 g of NaOH was added in the preparation of the sixth suspension. Comparative Example 3

[0228] The binder compositions were prepared in the same manner as in Example 2, except that 51.0 g of AA was added in the preparation of the second suspension, 10.2 g of AM was added in the preparation of the third suspension, 6.8 g of AN was added in the preparation of the fourth suspension, and 10.42 g of NaOH was added in the preparation of the sixth suspension. Comparative Example 4

[0229] The binder compositions were prepared in the same manner as in Example 2, except that 46.92 g of AA was added in the preparation of the second suspension, 5.44 g of AM was added in the preparation of the third suspension, 15.64 g of AN was added in the preparation of the fourth suspension, and 8.23 g of NaOH was added in the preparation of the sixth suspension. Comparative Example 5

[0230] Binder compositions were prepared in the same manner as in Example 2, except that 30.6 g of AA was added in the preparation of the second suspension, 30.6 g of AM was added in the preparation of the third suspension, and 6.8 g of AN was added in the preparation of the fourth suspension. Comparative Example 6

[0231] The binder compositions were prepared in the same manner as in Example 2, except that 8 g of NaOH was added in the preparation of the first suspension, 20.4 g of AA was added in the preparation of the second suspension, 31.96 g of AM was added in the preparation of the third suspension, 15.64 g of AN was added in the preparation of the fourth suspension, and 3.21 g of NaOH was added in the preparation of the sixth suspension. Comparative Example 7

[0232] The binder compositions were prepared in the same manner as in Example 2, except that 5 g of NaOH was added in the preparation of the first suspension, 13.6 g of AA was added in the preparation of the second suspension, 27.2 g of AM was added in the preparation of the third suspension, 27.2 g of AN was added in the preparation of the fourth suspension, and 2.1 g of NaOH was added in the preparation of the sixth suspension. Comparative Example 8

[0233] The binder compositions were prepared in the same manner as in Example 2, except that 57.8 g of AA was added in the preparation of the second suspension, 6.8 g of AM was added in the preparation of the third suspension, 3.4 g of AN was added in the preparation of the fourth suspension, and 13.5 g of NaOH was added in the preparation of the sixth suspension. Comparative Example 9

[0234] The binder compositions were prepared in the same manner as in Example 2, except that 34.0 g of AA and 6.8 g of methyl acrylate (MA) were added in the preparation of the second suspension, 13.6 g of AM was added in the preparation of the third suspension, 13.6 g of AN was added in the preparation of the fourth suspension, and 3.72 g of NaOH was added in the preparation of the sixth suspension. Comparative Example 10

[0235] The binder compositions were prepared in the same manner as in Example 2, except that 34.0 g of AA was added in the preparation of the second suspension, 14.96 g of AM was added in the preparation of the third suspension, and 19.04 g of AN was added in the preparation of the fourth suspension. Preparation of positive electrodes of Examples 2 to 11, 15 to 16 and Comparative Examples 1 to 10

[0236] The positive electrodes of Examples 2 to 11, 15 and 16 and Comparative Examples 1 to 10 were prepared in the same manner as in Example 1. Preparation of the positive electrode of Example 12

[0237] The positive electrode of Example 12 was prepared in the same manner as in Example 1, except that 28.2 g of NMC622 was replaced with the same weight of NMC532 (obtained from Tianjin BoMao Technology Co., Ltd., China). Preparation of the positive electrode of Example 13

[0238] The positive electrode of Example 13 was prepared in the same manner as in Example 1, except that 28.2 g of NMC622 was replaced with the same weight of LiCoO2 (obtained from Tianjin Baomao Technology Co., Ltd., China). Preparation of the positive electrode of Example 14

[0239] The positive electrode of Example 14 was prepared in the same manner as in Example 1, except that 28.2 g of NMC622 was replaced with the same weight of LiFePO4 (obtained from Xiamen Tungsten Industry Co., Ltd., China). Preparation of negative electrodes in Examples 2 to 16 and Comparative Examples 1 to 10

[0240] The negative electrodes of Examples 2 to 16 and Comparative Examples 1 to 10 were prepared in the same manner as in Example 1. Assembly of coin batteries of Examples 2 to 16 and Comparative Examples 1 to 10

[0241] The coin batteries of Examples 2 to 16 and Comparative Examples 1 to 10 were assembled in the same manner as in Example 1. Electrochemical measurements of Examples 2 to 16 and Comparative Examples 1 to 10

[0242] The electrochemical performance of the coin batteries of Examples 2 to 16 and Comparative Examples 1 to 10 was measured in the same manner as in Example 1, and the test results are shown in Table 2 below. [Table 1] [Table 2]

[0243] While the present invention has been described with respect to a limited number of embodiments, the specific features of one embodiment should not be attributed to other embodiments of the invention. In some embodiments, the method may include numerous steps not mentioned herein. In other embodiments, the method does not include, or is substantially free of, any steps not recited herein. Variations and modifications from the described embodiments exist. The appended claims are intended to cover all such modifications and variations as fall within the scope of the present invention.

Claims

1. A binder composition for a secondary battery electrode, comprising a copolymer and a dispersion medium, wherein the copolymer comprises a structural unit (a) derived from a carboxylic acid group-containing monomer, a structural unit (b) derived from an amide group-containing monomer, and a structural unit (c) derived from a nitrile group-containing monomer.

2. The carboxylic acid group-containing monomers include acrylic acid, methacrylic acid, crotonic acid, 2-butylcrotonic acid, cinnamic acid, maleic acid, maleic anhydride, fumaric acid, itaconic acid, itaconic anhydride, tetraconic acid, 2-ethylacrylic acid, isocrotonic acid, cis-2-pentenoic acid, trans-2-pentenoic acid, angelic acid, tiglic acid, 3,3-dimethylacrylic acid, 3-propylacrylic acid, trans-2-methyl-3-ethylacrylic acid, cis-2-methyl-3-ethylacrylic acid, 3-isopropylacrylic acid, trans-3-methyl-3-ethylacrylic acid, cis-3-methyl-3-ethylacrylic acid, 2-isopropylacrylic acid, trimethylacrylic acid, 2-methyl- 3,3-Diethylacrylic acid, 3-butylacrylic acid, 2-butylacrylic acid, 2-pentylacrylic acid, 2-methyl-2-hexenoic acid, trans-3-methyl-2-hexenoic acid, 3-methyl-3-propylacrylic acid, 2-ethyl-3-propylacrylic acid, 2,3-diethylacrylic acid, 3,3-diethylacrylic acid, 3-methyl-3-hexylacrylic acid, 3-methyl-3-tert-butylacrylic acid, 2-methyl-3-pentylacrylic acid, 3-methyl-3-pentylacrylic acid, 4-methyl-2-hexenoic acid, 4-ethyl-2-hexenoic acid, 3-methyl-2-ethyl-2-hexenoic acid, 3-tert-butylacrylic acid, 2,3-dimethyl-3-ethylacrylic acid, 3,2. The binder composition of claim 1, wherein the acrylic acid is selected from the group consisting of 3-dimethyl-2-ethylacrylic acid, 3-methyl-3-isopropylacrylic acid, 2-methyl-3-isopropylacrylic acid, trans-2-octenoic acid, cis-2-octenoic acid, trans-2-decenoic acid, α-acetoxyacrylic acid, β-trans-allyloxyacrylic acid, α-chloro-β-E-methoxyacrylic acid, methyl maleate, dimethyl maleate, phenyl maleate, bromo maleate, chloromaleic acid, dichloromaleic acid, fluoromaleic acid, difluoromaleic acid, nonyl hydrogen maleate, decyl hydrogen maleate, dodecyl hydrogen maleate, octadecyl hydrogen maleate, fluoroalkyl hydrogen maleate, maleic anhydride, methyl maleate, dimethyl maleate, acrylic anhydride, methacrylic anhydride, methacrolein, methacryloyl chloride, methacryloyl fluoride, methacryloyl bromide, or a combination thereof.

3. 2. The binder composition of claim 1, wherein the proportion of structural units (a) in the copolymer derived from carboxylic acid group-containing monomers is about 33% to about 70% by mole, based on the total number of moles of monomer units of the copolymer in the binder composition.

4. 2. The binder composition of claim 1, wherein the amide group-containing monomer is selected from the group consisting of methacrylamide, N-methylmethacrylamide, N-ethylmethacrylamide, Nn-propylmethacrylamide, N-isopropylmethacrylamide, Nn-butylmethacrylamide, N-isobutylmethacrylamide, N,N-dimethylacrylamide, N,N-dimethylmethacrylamide, N,N-diethylacrylamide, N,N-diethylmethacrylamide, N-methylolmethacrylamide, N-(methoxymethyl)methacrylamide, N-(ethoxymethyl)methacrylamide, N-(propoxymethyl)methacrylamide, N-(butoxymethyl)methacrylamide, N,N-dimethylmethacrylamide, N,N-dimethylaminopropylmethacrylamide, N,N-dimethylaminoethylmethacrylamide, N,N-dimethylolmethacrylamide, diacetone methacrylamide, methacryloylmorpholine, and combinations thereof.

5. 2. The binder composition according to claim 1, wherein the proportion of structural units (b) derived from amide group-containing monomers in the copolymer is about 10% to about 35% by mole, based on the total number of moles of monomer units in the copolymer in the binder composition.

6. 2. The binder composition of claim 1, wherein the nitrile group-containing monomer is selected from the group consisting of acrylonitrile, α-halogenoacrylonitrile, α-alkylacrylonitrile, α-chloroacrylonitrile, α-bromoacrylonitrile, α-fluoroacrylonitrile, methacrylonitrile, α-ethylacrylonitrile, α-isopropylacrylonitrile, α-n-hexylacrylonitrile, α-methoxyacrylonitrile, 3-methoxyacrylonitrile, 3-ethoxyacrylonitrile, α-acetoxyacrylonitrile, α-phenylacrylonitrile, α-tolylacrylonitrile, α-(methoxyphenyl)acrylonitrile, α-(chlorophenyl)acrylonitrile, α-(cyanophenyl)acrylonitrile, vinylidene cyanide, and combinations thereof.

7. 2. The binder composition according to claim 1, wherein the proportion of structural units (c) derived from nitrile group-containing monomers in the copolymer is about 10% to about 30% by mole, based on the total number of moles of monomer units in the copolymer in the binder composition.

8. The binder composition of claim 1 , wherein the dispersion medium is water.

9. 9. The binder composition of claim 8, wherein the dispersion medium further comprises a hydrophilic solvent selected from the group consisting of ethanol, isopropanol, n-propanol, tert-butanol, n-butanol, dimethylacetamide (DMAc), dimethylformamide (DMF), N-methylpyrrolidone (NMP), methyl ethyl ketone (MEK), ethyl acetate (EA), butyl acetate (BA), and combinations thereof.

10. 2. The binder composition according to claim 1, wherein the total proportion of the structural units (a) derived from the carboxylic acid group-containing monomer and the structural units (c) derived from the nitrile group-containing monomer in the copolymer is about 65% to about 90% by mole, based on the total number of moles of monomer units in the copolymer of the binder composition.

11. 2. The binder composition according to claim 1, wherein a molar ratio of the total of the structural units (a) derived from a carboxylic acid group-containing monomer and the structural units (c) derived from a nitrile group-containing monomer to the structural units (b) derived from an amide group-containing monomer in the copolymer is from about 1 to about 7.

12. 2. The binder composition according to claim 1, wherein a molar ratio of the total of the structural units (a) derived from the carboxylic acid group-containing monomer and the structural units (b) derived from the amide group-containing monomer to the structural units (c) derived from the nitrile group-containing monomer in the copolymer is from about 1 to about 7.

13. The binder composition of claim 1 , wherein the pH of the binder composition is from about 7 to about 9.

14. The binder composition of claim 1, wherein the viscosity of the binder composition is from about 10,000 mPa·s to about 50,000 mPa·s.

15. The binder composition of claim 1 , wherein the electrolyte swelling of the binder composition is from about 7% to about 10%.

16. 2. The binder composition according to claim 1, wherein the adhesive strength between the binder composition and the current collector is from about 2 N / cm to about 4 N / cm.

17. The binder composition of claim 1, wherein the solids content of the binder composition is from about 5% to about 10% by weight, based on the total weight of the binder composition.

18. An electrode for a secondary battery, comprising an electrode active material, a conductive agent, and the binder composition according to claim 1 .

19. 19. The electrode for a secondary battery according to claim 18, wherein the peel strength between the current collector and the electrode layer is in the range of about 1.0 N / cm to about 8.0 N / cm.

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