Binder composition for secondary battery

Abstract

The aqueous binder composition for a positive electrode of a secondary battery electrode includes a copolymer and a dispersion medium, the copolymer including 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 has improved bonding properties. Furthermore, battery cells including cathodes fabricated using the binder composition disclosed herein exhibit excellent electrochemical performance.

Description

Technical Field

[0001] The present invention relates to the field of batteries. In particular, the present invention relates to a binder composition for lithium-ion batteries.

Background Art

[0002] Over the past few decades, lithium-ion batteries (LIBs) have been widely used in various applications, especially in household 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 and low-cost LIBs currently offer one of the most promising options for large-scale energy storage devices.

[0003] Generally, the electrodes of lithium-ion batteries are manufactured by casting an organic-based slurry on a metal current collector. The slurry contains an electrode active material, conductive carbon, and a binder in an organic solvent. The binder is electrochemically stable, connects the electrode active materials, and adheres to the current collector to manufacture the electrode. Polyvinylidene fluoride (PVDF) is one of the most commonly used binders in the commercial lithium-ion battery industry. However, since PVDF is insoluble in water and only soluble in specific organic solvents such as flammable and toxic N-methyl-2-pyrrolidone (NMP), special handling is required.

[0004] To recover NMP vapor, it is necessary to install an NMP recovery device in the drying process. Since this requires a large equipment investment, it will incur a large cost in the manufacturing process. Using a cheaper and environmentally friendly solvent, such as an aqueous solvent, most commonly water, is preferred in the present invention because it can reduce the large capital cost 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 the use of organic solvents during production that require specific recovery treatments.

[0006] Known water-based binders such as carboxymethyl cellulose (CMC) and styrene butadiene rubber (SBR) exhibit only marginal adhesive ability and poor cycle life. SBR in particular requires thickeners to adjust binder viscosity. SBR also has high expansion and unfavorable cohesive properties, which lead to inhomogeneous dispersion, high electrode resistance, and poor performance. Furthermore, high voltages are applied to the cathode in the battery. Most rubbers, including SBR, are stable only at low anode voltages and decompose at high voltages. Therefore, their application, especially 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 at least one combination of PVDF and SBR, and polyacrylic acid (PAA) and CMC in an aqueous solution, and an electrochemically active material. The proposed invention seeks to combine PVDF with an aqueous slurry that allows easier handling and reduced environmental pollution and reduced costs, while maintaining the known chemical and electrochemical advantages of PVDF as a binder, i.e. electrochemical stability, lifetime stability, reduced binder content allows higher C-rates, etc. Despite the fact that organic solvent-free slurries can be prepared based on the proposed invention, the slurries are nevertheless composed of fluorine-containing binder materials. PVDF is highly fluorinated and is toxic when exposed to thermal decomposition, posing risks to people's health and the environment.

[0008] From the above, in the preparation of the cathode slurry, an aqueous binder composition for a lithium-ion battery that exhibits excellent adhesion ability and high electrochemical stability, whose properties are sustained, and that contributes to excellent battery electrochemical performance, is always required.

Summary of the Invention

[0009] The aforementioned needs are satisfied by various aspects and embodiments disclosed herein. Provided herein is a binder composition for a secondary battery electrode comprising a copolymer and a dispersion medium, wherein the copolymer consists of 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, and is a binder with improved binding ability. Also, a battery cell comprising a cathode prepared using the binder composition disclosed herein exhibits excellent electrochemical performance.

Brief Description of the Drawings

[0010]

Figure 1

Modes for Carrying Out the Invention

[0011] Provided herein is 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.

[0012] The term "electrode" means "cathode" or "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, a mixture of compounds, or a polymer that forms a colloidal solution or colloidal dispersion in a dispersion medium such as water, and is used to hold an electrode material and / or a conductive agent in a predetermined position and adhere it onto a conductive metal portion to form an electrode. In some embodiments, the electrode does not contain any conductive agent.

[0015] The term "conductive agent" means a material that is chemically inert and has good electrical conductivity. Thus, the conductive agent is often mixed with an electrode active material 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" includes not only the term "homopolymer" but also the term "copolymer".

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

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

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

[0020] The term "alkyl" or "alkyl group" refers to a monovalent group having the general formula C n H 2n+1 obtained by removing a hydrogen atom from a saturated, unbranched or branched aliphatic hydrocarbon, where n means an integer between 1 and 20, or an integer between 1 and 8. Examples of alkyl groups include (C 1 -C 8)There are alkyl groups and the like, but not limited thereto. For example, 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, octyl and the like can be mentioned. Long-chain alkyl groups include nonyl and decyl groups. The alkyl group may be unsubstituted or substituted with one or more suitable substituents. Further, the alkyl group can be branched or unbranched. In some embodiments, the alkyl group contains at least 2, 3, 4, 5, 6, 7, or 8 carbon atoms.

[0021] The term "cycloalkyl" or "cycloalkyl group" means a saturated or unsaturated cyclic non-aromatic hydrocarbon radical having a single ring or a plurality of fused rings. Examples of cycloalkyl groups include (C 3 -C 7 ) cycloalkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, and cycloheptyl, and saturated cyclic and bicyclic terpenes, and (C 3 -C 7 ) cycloalkenyl groups such as cyclopropenyl, cyclobutenyl, cyclopentenyl, cyclohexenyl, and cycloheptenyl, and unsaturated cyclic and bicyclic terpenes, but are not limited thereto. The cycloalkyl group may be unsubstituted or substituted with one or two suitable substituents. Further, the cycloalkyl group can be monocyclic or polycyclic. In some embodiments, the 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 that is bonded to the main carbon chain through an oxygen atom. Some non-limiting examples of alkoxy groups include methoxy, ethoxy, propoxy, butoxy, and the like. And the alkoxy defined above may or may not be substituted, where the substituents may be, but are not limited to, deuterium, hydroxy, amino, halo, cyano, alkoxy, alkyl, alkenyl, alkynyl, mercapto, nitro, and the like.

[0023] The term "alkenyl" means 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, and these may optionally be 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 tranyl groups, sexiphenylene, phenanthrenyl, anthracenyl, coronenyl, and tranylphenyl. The aryl group can be unsubstituted or substituted with one or more suitable substituents. Further, the aryl group can be monocyclic or polycyclic. In some embodiments, the aryl group contains at least 6, 7, 8, 9, or 10 carbon atoms.

[0025] The term "aliphatic" refers to C 1 ~C 30 alkyl group, C 2 ~C 30 alkenyl group, C 2 ~C 30 alkynyl group, C 1 ~C 30 alkylene group, C 2 ~C 30 alkenylene group, or C 2 ~C 30It means 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" as used to describe a compound or chemical moiety means that at least one hydrogen atom of the compound or chemical moiety is replaced by a second chemical moiety. Examples of substituents include halogen; alkyl; heteroalkyl; alkenyl; alkynyl; aryl, heteroaryl, hydroxyl; alkoxyl; amino; nitro; thiol; thioether; imine; cyano; amide; phosphonate; phosphine; carboxyl; thiocarbonyl; sulfonyl; sulfonamide; acyl; formyl; acyloxy; alkoxycarbonyl; oxo; haloalkyl (e.g., (trifluoromethyl)); a carbocyclic cycloalkyl which can be monocyclic or fused or non - fused polycyclic (e.g., cyclopropyl, cyclobutyl, cyclopentyl or cyclohexyl) or a heterocyclic cycloalkyl which can be monocyclic or fused or non - fused polycyclic (e.g., pyrrolidinyl, piperidinyl, piperazinyl, morpholinyl or thiazinyl); a carbocyclic or heterocyclic, monocyclic or fused or non - fused polycyclic aryl (e.g., phenyl, naphthyl, pyrrolyl, indolyl, furanyl, thiophenyl, imidazolyl, oxazolyl, isoxazolyl, thiazolyl, 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; -CO 2CH 3 ;-CONH 2 ;-OCH 2 CONH 2 ;-NH 2 ;-SO 2 NH 2 ;-OCHF 2 ;-CF 3 ;-OCF 3 ;-NH(alkyl); -N(alkyl) 2 ;-NH(aryl); -N(alkyl)(aryl); -N(aryl) 2 ;-CHO; -CO(alkyl); -CO(aryl); -CO 2 (alkyl); and -CO 2 (aryl); and such moieties may also be optionally substituted by a fused ring structure or a bridge, e.g., -OCH 2 O-. These substituents may optionally be further substituted with substituents selected from such groups. All chemical groups disclosed herein are substitutable 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 base" means a carboxylate 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 "coating" 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 the electrode layer and can conduct the current flowing to the electrode during discharge or charging of the secondary battery. Some non-limiting examples of the current collector include a single conductive metal layer or substrate, and a single conductive metal layer or substrate having a conductive coating layer such as a carbon black-based coating layer thereon. 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 polymer material, a metal 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" means a layer containing an electrochemically active material that is in contact with the current collector. In some embodiments, the electrode layer is made by applying a coating on the current collector. In some embodiments, the electrode layer is located on the surface of the current collector. In other embodiments, the three-dimensional porous current collector is conformally coated with the electrode layer.

[0035] The term "room temperature" refers to an indoor temperature of about 18°C to about 30°C, for example, an indoor temperature of 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] "Particle size D50" means the volume-based cumulative 50% size (D50), which is the particle size at the 50% point on the cumulative curve (i.e., the diameter of the particles with 50% of the particle volume (median value)) when a cumulative curve is drawn so that the particle size distribution is obtained on a volume basis. Further, with respect to the cathode active material of the present invention, the particle size D50 means the volume average particle size of secondary particles that can be formed by the mutual aggregation of primary particles, and when composed only of primary particles, it means the volume average particle size of the primary particles.

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

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

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

[0040] The term "peel strength" refers to the magnitude of the force required to separate the current collector and the electrode active material film that are bonded to each other. This is a measure of the bonding strength between such two materials and is usually expressed in N / cm.

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

[0042] The term "swelling" means the volume change of the binder composition after immersion in the electrolyte, or the uptake of the electrolyte due to the electrolyte-binder interaction.

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

[0044] The term "ampere-hour (Ah)" refers to the unit used when defining the power storage 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) corresponds to a charge of 3,600 coulombs. Similarly, the term "milliampere-hour (mAh)" also means the unit of the power storage capacity of a battery and is 1 / 1000 of 1 ampere-hour.

[0045] The term "battery cycle life" means the number of complete charge and discharge cycles that can be performed until the nominal capacity of the battery drops below 80% of the initial rated capacity.

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

[0047] In the following description, all numerical values disclosed in this specification are approximate values regardless of whether the words "about" or "approximate" are used in connection with them. They may vary by 1 percent, 2 percent, 5 percent, or in some cases 10 - 20 percent. Lower limit value R L and upper limit value R U Whenever a numerical range with a lower limit value R L + k * (R U - R L ) is disclosed, any numerical value within that range is specifically disclosed. In particular, the numerical values within the following ranges are specifically disclosed. R = R

[0048] Currently, the cathode is 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, and applying and drying the cathode slurry on a current collector.

[0049] In many cases, since the binder is considered an electrochemically inert material, its impact on cell performance has been underestimated. The purpose of the binder is to adhere the active material particles and the conductive agent together and form a continuous electrical conduction path to the current collector. In addition to the binding ability, the binder material should be able to facilitate electron and ion transport to reduce the impedance between the current collector and the electrode material, and have sufficient elasticity to prevent the expansion of the electrode due to volume expansion and contraction during charge and discharge.

[0050] Polyvinylidene fluoride (PVDF) is widely used as a binder material in the manufacture of lithium-ion batteries. However, since PVDF dissolves only in specific organic solvents such as flammable and toxic NMP, specific handling is required. Also, in the drying process, it is necessary to install an NMP recovery device to recover the vapor of NMP. For this reason, the energy consumption and manufacturing cost in the manufacturing process increase. Therefore, the search for a new environmentally friendly binder material 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 part of the representative aqueous binders already used in large-scale commercial applications. However, these binders have limitations in binding ability and the ability to prevent electrode expansion. Furthermore, a high voltage is applied to the cathode in the battery. Most rubbers containing SBR are stable only at the low voltage of the anode and decompose at high voltage. Therefore, its application to the cathode in particular is rather limited.

[0052] Accordingly, the present invention provides a method for preparing an aqueous binder composition comprising a copolymer and a dispersion 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. FIG. 1 is a flowchart of an embodiment showing the steps of method 100 for preparing a binder composition. The binder composition described herein has been found to exhibit improved adhesion ability and, at the same time, has an unexpected effect of improving the capacity and electrochemical performance of the cathode formed therefrom.

[0053] In some embodiments, the binder composition described herein is produced via polymerization in which monomers, polymers, or monomer-polymer composites are dispersed in an aqueous phase while generating free radicals with a water-soluble free radical initiator.

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

[0055] Establishing the desired pH range for operation is particularly important in an aqueous system. 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 free radical initiators, neutralizing agents, and other components. In some embodiments, the binder compositions disclosed herein are prepared by an aqueous treatment 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 first suspension is stirred for a time of about 5 minutes to about 45 minutes, about 5 minutes to about 40 minutes, about 5 minutes to about 35 minutes, about 5 minutes to about 30 minutes, about 5 minutes to about 25 minutes, about 5 minutes to about 20 minutes, or about 10 minutes to about 20 minutes. In some embodiments, the first suspension is stirred for a time 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 first suspension is stirred for a time longer than 5 minutes, longer than 10 minutes, longer than 15 minutes, longer than 20 minutes, longer than 25 minutes, longer than 30 minutes, longer than 35 minutes, or longer than 40 minutes.

[0059] In some embodiments, the first suspension is stirred at a speed of about 10 rpm to about 600 rpm, about 50 rpm to about 600 rpm, about 100 rpm to about 600 rpm, about 150 rpm to about 600 rpm, about 200 rpm to about 600 rpm, about 250 rpm to about 600 rpm, about 300 rpm to about 600 rpm, about 300 rpm to about 550 rpm, about 300 rpm to about 500 rpm, about 320 rpm to about 480 rpm, about 340 rpm to about 460 rpm, or about 360 rpm to about 440 rpm. In some embodiments, the first suspension is stirred at a speed 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 first suspension is stirred at a speed faster than 10 rpm, faster than 50 rpm, faster than 100 rpm, faster than 150 rpm, faster than 200 rpm, faster than 250 rpm, faster than 300 rpm, faster than 350 rpm, faster than 400 rpm, faster than 450 rpm, faster than 500 rpm, or faster than 550 rpm.

[0060] In some embodiments, the second suspension is formed by adding a carboxylic acid group-containing monomer to the first suspension in step 102.

[0061] 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 certain 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 combinations thereof. In specific 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, 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 combinations thereof.In some embodiments, the carboxylic acid group-containing monomer is methyl maleate, dimethyl maleate, phenyl maleate, bromo maleate, chloro maleic acid, dichloro maleic acid, fluoro maleic 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 maleic anhydride, dimethyl maleic anhydride, acrylic anhydride, methacrylic anhydride, methacrolein, methacryloyl chloride, methacryloyl fluoride, methacryloyl bromide, or a combination thereof.

[0062] In some embodiments, the proportion of the carboxylic acid group-containing monomer is by weight based on the total weight of the monomers added in the preparation of the binder composition, about 10% to about 30%, about 10% to about 25%, about 10% to about 20%, about 10% to about 15%, 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 15% to about 25%, about 15% to about 20%, about 15% to about 29%, about 15% to about 28%, about 15% to about 27%, about 15% to about 26%, about 15% to about 25%, about 16% to about 25%, about 17% to about 25%, about 18% to about 25%, about 19% to about 25%, about 20% to about 30%, about 20% to about 25%, about 17% to about 23%, about 15% to about 20%, or about 17% to about 26%.

[0063] In some embodiments, the proportion of the carboxylic acid group-containing monomer 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 weight based on the total weight of the monomers added in the preparation of the binder composition. In some embodiments, the proportion of the carboxylic acid group-containing monomer is more than 10%, more than 11%, more than 12%, more than 13%, more than 14%, more than 15%, more than 16%, more than 17%, more than 18%, more than 19%, more than 20%, more than 21%, more than 22%, more than 23%, more than 24%, more than 25%, more than 26%, more than 27%, more than 28%, or more than 29% by weight based on the total weight of the monomers added in the preparation of the binder composition.

[0064] In some embodiments, one or more carboxylic acid group-containing monomers may be added to the first suspension in step 102 to form a second suspension. This can be advantageous as it allows for better dispersion and prevents precipitation of the material in the treatment of the binder composition disclosed herein. It has been found that the addition of one or more carboxylic acid group-containing monomers to the binder composition can increase the monomer conversion rate, thus maximizing the complete use of the starting materials and simultaneously bringing about significant cost reduction and environmental benefits. In addition, when one or more carboxylic acid group-containing monomers are applied in the preparation of the binder composition, slightly better battery electrochemical performance is subsequently observed.

[0065] In some embodiments, the copolymer comprises structural units (a1) derived from a first carboxylic acid group-containing monomer, structural units (a2) derived from a second 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. In some embodiments, in step 102, the first carboxylic acid group-containing monomer and the second carboxylic acid group-containing monomer may be added to the first suspension to form a second suspension.

[0066] In some embodiments, the copolymer is composed of a structural unit (a1) derived from a first carboxylic acid group-containing monomer, a structural unit (a2) derived from a second 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.

[0067] In some embodiments, the structural unit (a1) is derived from a first carboxylic acid group-containing monomer. In some embodiments, the first carboxylic acid group-containing monomer is acrylic acid.

[0068] In some embodiments, the structural unit (a2) is derived from a second carboxylic acid group-containing monomer. In some embodiments, the second carboxylic acid group-containing monomer is acrylic acid substituted with an alkyl group. In some embodiments, the second carboxylic acid group-containing monomer is methacrylic acid, crotonic acid, 2-butylcrotonic 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, 3,3-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 or a combination thereof.

[0069] In some embodiments, the proportion of the first carboxylic acid group-containing monomer is about 5% to about 30%, about 5.5% to about 30%, about 6% to about 30%, about 6.5% to about 30%, about 7% to about 30%, about 7.5% to about 30%, about 8% to about 30%, about 8.5% to about 30%, about 9% to about 30%, about 9.5% to about 30%, about 10% to about 30%, about 10% to about 29.5%, about 10% to about 29%, about 10% to about 28.5%, about 10% to about 28%, about 10% to about 27.5%, about 10% to about 27%, about 10% to about 26.5%, about 10% to about 26%, about 10% to about 25.5%, about 10% to about 25%, about 10% to about 24.5%, about 10% to about 24%, about 10% to about 23.5%, about 10% to about 23%, about 10% to about 22.5%, about 10% to about 22%, about 10% to about 21.5%, about 10% to about 21%, about 10% to about 20.5%, or about 10% to about 20% by weight, based on the total weight of the monomers added in the preparation of the binder composition.

[0070] In some embodiments, the proportion of the first carboxylic acid group-containing monomer 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%, or less than 6% by weight, based on the total weight of the monomers added during the preparation of the binder composition. In some embodiments, the proportion of the first carboxylic acid group-containing monomer is more than 5%, more than 6%, more than 7%, more than 8%, more than 9%, more than 10%, more than 11%, more than 12%, more than 13%, more than 14%, more than 15%, more than 16%, more than 17%, more than 18%, more than 19%, more than 20%, more than 21%, more than 22%, more than 23%, more than 24%, more than 25%, more than 26%, more than 27%, more than 28%, or more than 29% by weight, based on the total weight of the monomers added in the preparation of the binder composition.

[0071] In some embodiments, the proportion of the second carboxylic acid group-containing monomer is about 1% to about 7%, about 1.2% to about 7%, about 1.4% to about 7%, about 1.6% to about 7%, about 1.8% to about 7%, about 2% to about 7%, about 2.2% to about 7%, about 2.4% to about 7%, about 2.6% to about 7%, about 2.8% to about 7%, about 3% to about 7%, about 3 to about 6.8%, about 3% to about 6.6%, about 3% to about 6.4%, about 3.2% to about 6.4%, about 3.4% to about 6.4%, about 3.6% to about 6.4%, about 3.8% to about 6.4%, about 4% to about 6.4%, about 4% to about 6.2%, about 4% to about 6%, about 3.5% to about 6%, about 3% to about 6%, or about 3% to about 6.5% by weight, based on the total weight of the monomers added in the preparation of the binder composition.

[0072] In some embodiments, the proportion of the second carboxylic acid group-containing monomer 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%, or less than 1.4% by weight, based on the total weight of the monomers added during the preparation of the binder composition. In some embodiments, the proportion of the second carboxylic acid group-containing monomer is more than 1%, more than 1.2%, more than 1.4%, more than 1.6%, more than 1.8%, more than 2%, more than 2.2%, more than 2.4%, more than 2.6%, more than 2.8%, more than 3%, more than 3.2%, more than 3.4%, more than 3.6%, more than 3.8%, more than 4%, more than 4.2%, more than 4.4%, more than 4.6%, more than 4.8%, more than 5%, more than 5.2%, more than 5.4%, more than 5.6%, more than 5.8%, more than 6%, more than 6.2%, more than 6.4%, or more than 6.6% by weight, based on the total weight of the monomers added in the preparation of the binder composition.

[0073] In some embodiments, the weight ratio of the first carboxylic acid group-containing monomer to the second carboxylic acid group-containing monomer added in the preparation of the binder composition is from about 1 to about 15, from about 1 to about 14.5, from about 1 to about 14, from about 1 to about 13.5, from about 1 to about 13, from about 1 to about 12.5, from about 1 to about 12, from about 1 to about 11.5, from about 1 to about 11, from about 1 to about 10.5, from about 1 to about 10, from about 1 to about 9.5, from about 1 to about 9, from about 1 to about 8.5, from about 1 to about 8, from about 1.5 to about 10, from about 2 to about 10 , about from about 2.5 to about 10, from about 3 to about 10, from about 3.5 to about 10, from about 4 to about 10, from about 4.5 to about 10, from about 5 to about 10, or from about 2 to about 8.

[0074] In some embodiments, the weight ratio of the first carboxylic acid group-containing monomer to the second carboxylic acid group-containing monomer added in the preparation of the binder composition is 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. In some embodiments, the weight ratio of the first carboxylic acid group-containing monomer to the second carboxylic acid group-containing monomer added in the preparation of the binder composition is 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, or greater than 14.

[0075] In some embodiments, in step 103, by adding an amide group-containing monomer to the second suspension, a third suspension is formed.

[0076] In some embodiments, the amide group-containing monomer solution is prepared by dissolving the amide group-containing monomer in water. In some embodiments, the third suspension is formed by adding the amide group-containing monomer solution to the second suspension in step 103.

[0077] The structural unit (b) is derived from an amide group-containing monomer. Monomers having at least one amide group can be used as the amide group-containing monomer without particular limitation. In some embodiments, the amide group-containing monomer is acrylamide, methacrylamide, N-methylmethacrylamide, N-ethylmethacrylamide, N-n-propylmethacrylamide, N-isopropylmethacrylamide, isopropylacrylamide, N-n-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-dimethylaminopropylmethacrylamide, N,N-dimethylaminoethylmethacrylamide, N,N-dimethylolmethacrylamide, diketone methacrylamide, diacetone acrylamide, methacryloylmorpholine, N-hydroxylmethacrylamide, N-methoxymethylacrylamide, N-methoxymethylmethacrylamide, N,N'-methylene-bis-acrylamide (MBA), N-hydroxymethylacrylamide, or a combination thereof.

[0078] In some embodiments, the proportion of the amide group-containing monomer is about 5% to about 20%, about 5% to about 15%, about 5% to about 10%, about 6% to about 20%, about 7% to about 20%, about 8% to about 20%, about 9% to about 20%, about 10% to about 20%, about 10% to about 19%, about 10% to about 18%, about 10% to about 17%, about 10% to about 16%, about 10% to about 15%, about 8% to about 17%, about 7% to about 13%, about 12% to about 18%, or about 15% to about 20% by weight, based on the total weight of the monomers added in the preparation of the binder composition.

[0079] In some embodiments, the proportion of the amide group-containing monomer is less than 20% by weight, less than 19% by weight, less than 18% by weight, less than 17% by weight, less than 16% by weight, less than 15% by weight, less than 14% by weight, less than 13% by weight, less than 12% by weight, less than 11% by weight, less than 10% by weight, less than 9% by weight, less than 8% by weight, less than 7% by weight, or less than 6% by weight, based on the total weight of the monomers added in the preparation of the binder composition. In some embodiments, the proportion of the amide group-containing monomer is more than 5% by weight, more than 6% by weight, more than 7% by weight, more than 8% by weight, more than 9% by weight, more than 10% by weight, more than 11% by weight, more than 12% by weight, more than 13% by weight, more than 14% by weight, more than 15% by weight, more than 16% by weight, more than 17% by weight, more than 18% by weight, or more than 19% by weight, based on the total weight of the monomers added in the preparation of the binder composition.

[0080] In some embodiments, the fourth suspension is formed by adding a nitrile group-containing monomer to the third suspension in step 104.

[0081] The structural unit (c) is derived from a nitrile group-containing monomer. Monomers having at least one nitrile group can be used as the nitrile group-containing monomer without 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.

[0082] In some embodiments, the proportion of the nitrile group-containing monomer is, by weight, about 60% to about 75%, about 60% to about 74.5%, about 60% to about 74%, about 60% to about 73.5%, about 60% to about 73%, about 60% to about 72.5%, about 60% to about 72%, about 60% to about 71.5%, about 60% to about 71%, about 60% to about 70.5%, about 60% to about 70%, about 60% to about 69.5%, about 60% to about 69%, about 60% to about 68.5%, about 60% to about 68%, about 60% to about 67.5%, about 60% to about 67%, about 60% to about 66.5%, about 60% to 66%, about 60% to 65.5%, about 60% to 65%, 65% to about 75%, about 65% to about 70%, about 63% to 75%, or about 70% to 75%, based on the total weight of the monomers added in the preparation of the binder composition.

[0083] In some embodiments, the proportion of the nitrile group-containing monomer is, by weight, more than 60%, more than 61%, more than 62%, more than 63%, more than 64%, more than 65%, more than 66%, more than 67%, more than 68%, more than 69%, more than 70%, more than 71%, more than 72%, more than 73%, or more than 74%, based on the total weight of the monomers added in the preparation of the binder composition. In some embodiments, the proportion of the nitrile group-containing monomer is, by weight, less than 75%, less than 74%, less than 73%, less than 72%, less than 71%, 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%, or less than 61%, based on the total weight of the monomers added in the preparation of the binder composition.

[0084] 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 the third and fourth suspensions. In other embodiments, a carboxylic acid group-containing monomer, a nitrile group-containing monomer, an amide group-containing monomer, or a combination thereof is sequentially added to the first suspension to form the second suspension, the third suspension, or the fourth suspension. Stirring or dispersion may be employed during these additions. This is advantageous because it can better disperse the materials. When the monomer combination is added sequentially, formation of the third or fourth suspension can be omitted.

[0085] In some embodiments, the copolymer is obtained via polymerization of the composition. In some embodiments, the composition comprises 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, formation of the carboxylate group-containing monomer results from neutralization of the carboxylic acid group-containing monomer by the neutralizing agent added in step 101.

[0086] In one embodiment, the carboxy base-containing monomer is acrylate, methacrylate, crotonate, 2-butylcrotonate, cinnamate, maleate, maleic anhydride, fumarate, itaconate, itaconic anhydride, tetraconate, or a combination thereof. In certain embodiments, the carboxylate base-containing monomer is 2-ethylacrylate, isocrotonate, cis-2-pentenoate, trans-2-pentenoate, angelate, tiglate, 3,3-dimethylacrylate, 3-propylacrylate, trans-2-methyl-3-ethylacrylate, cis-2-methyl-3-ethylacrylate, 3-isopropylacrylate, trans-3-methyl-3-ethylacrylate, cis-3-methyl-3-ethylacrylate, 2-isopropylacrylate, trimethylacrylate, 2-methyl-3,3-diethylacrylate, 3-butylacrylate, 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-2-ethyl-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 carboxyl base-containing monomer is methyl maleate, dimethyl maleate, phenyl maleate, bromo maleate, chloro maleate, dichloro maleate, fluoro maleate, difluoro maleate, or a combination thereof.

[0087] In some embodiments, the carboxylate base-containing monomer is an alkali metal carboxylate base-containing monomer. Examples of alkali metals that form alkali metal carboxylates include lithium, sodium, and potassium. In some embodiments, the carboxylate base-containing monomer is an ammonium carboxylate base-containing monomer.

[0088] In some embodiments, the molar ratio of the carboxylic acid group-containing monomer to the carboxylate base-containing monomer in the composition is from about 0 to about 1.5, from about 0 to about 1.45, from about 0 to about 1.4, from about 0 to about 1.35, from about 0 to about 1.3, from about 0 to about 1.25, from about 0 to about 1.2, from about 0 to about 1.15, from about 0 to about 1.1, from about 0 to about 1.05, from about 0 to about 1, from about 0 to about 0.95, from about 0 to about 0.9, from about 0 to about 0.85, from about 0 to about 0.8, from about 0 to about 0.75, from about 0 to about 0.7, from about 0 to about 0.65, from about 0 to about 0.6, from about 0 to about 0.55, from about 0 to about 0.5, from about 0 to about 0.45, from about 0 to about 0.4, from about 0.05 to about 0.5, from about 0.1 to about 0.7, or from about 0.1 to about 1.

[0089] In some embodiments, the molar ratio of the carboxylic acid group-containing monomer to the carboxylate base-containing monomer in the composition is less than 1.5, less than 1.4, less than 1.3, less than 1.2, less than 1.1, less than 1, less than 0.9, less than 0.8, less than 0.7, less than 0.6, less than 0.5, less than 0.4, less than 0.3, or less than 0.2. In some embodiments, the molar ratio of the carboxylic acid group-containing monomer to the carboxylate base-containing monomer in the composition is greater than 0, greater than 0.1, greater than 0.2, greater than 0.3, greater than 0.4, greater than 0.5, greater than 0.6, greater than 0.7, greater than 0.8, greater than 0.9, greater than 1, greater than 1.1, greater than 1.2, or greater than 1.3.

[0090] In some embodiments, the proportion of the carboxylic acid group-containing monomer is, in moles, about 0% to about 15%, about 0% to about 14.5%, about 0% to about 14%, about 0% to about 13.5%, about 0% to about 13%, about 0% to 12.5%, about 0% to about 12%, about 0% to about 11.5%, about 0% to about 11%, about 0% to 10.5%, about 0% to 10%, about 0% to about 9.5%, about 0% to about 9%, about 0% to about 8.5%, about 0% to about 8%, about 0% to about 7.5%, about 0% to about 7%, about 0% to about 6.5%, about 0% to about 6%, about 0% to about 5.5%, about 0% to about 5%, about 0.5% to about 10%, about 1% to about 10%, or about 1% to about 8%, based on the total number of moles of monomers in the composition.

[0091] In some embodiments, the proportion of the carboxylic acid group-containing monomer is, in moles, 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%, based on the total number of moles of monomers in the composition. In some embodiments, the proportion of the carboxylic acid group-containing monomer is, in moles, more than 0%, more than 1%, more than 2%, more than 3%, more than 4%, more than 5%, more than 6%, more than 7%, more than 8%, more than 9%, more than 10%, more than 11%, more than 12%, more than 13%, or more than 14%, based on the total number of moles of monomers in the composition.

[0092] In some embodiments, the proportion of the carboxylate group-containing monomer is, in moles, about 5% to about 16%, about 5.5% to about 16%, about 6% to about 16%, about 6.5% to about 16%, about 7% to about 16%, about 7.5% to about 16%, about 8% to about 16%, about 8.5% to about 16%, about 9% to about 16%, about 9.5% to about 16%, about 10% to about 16%, about 10% to about 15.5%, about 10% to about 15%, about 10.5% to about 15%, about 11% to about 15%, or about 8% to about 15%, based on the total number of moles of monomers in the composition.

[0093] In some embodiments, the proportion of the carboxylate group-containing monomer is 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%, or less than 6% in moles, based on the total number of moles of monomers in the composition. In some embodiments, the proportion of the carboxylate group-containing monomer is more than 5%, more than 6%, more than 7%, more than 8%, more than 9%, more than 10%, more than 11%, more than 12%, more than 13%, more than 14%, or more than 15% in moles, based on the total number of moles of monomers in the composition.

[0094] In some embodiments, the proportion of the nitrile group-containing monomer is about 65% to about 80%, about 65.5% to about 80%, about 66% to about 80%, about 66.5% to about 80%, about 67% to about 80%, about 67.5% to about 80%, about 68% to about 80%, about 68.5% to about 80%, about 69% to about 80%, about 69.5% to about 80%, about 70% to about 80%, about 70.5% to about 80%, about 71% to about 80%, about 71.5% to about 80%, about 72% to about 80%, about 65% to about 78%, about 65% to about 75%, about 68% to about 76%, about 70% to about 78%, or about 70% to about 75% in moles, based on the total number of moles of monomers in the composition.

[0095] In some embodiments, the proportion of the nitrile group-containing monomer is less than 80%, less than 79%, less than 78%, less than 77%, less than 76%, less than 75%, less than 74%, less than 73%, less than 72%, less than 71%, less than 70%, less than 69%, less than 68%, or less than 67% in moles, based on the total number of moles of monomers in the composition. In some embodiments, the proportion of the nitrile group-containing monomer is more than 65%, more than 66%, more than 67%, more than 68%, more than 69%, more than 70%, more than 71%, more than 72%, more than 73%, more than 74%, more than 75%, more than 76%, more than 77%, or more than 78% in moles, based on the total number of moles of monomers in the composition.

[0096] In some embodiments, the proportion of the amide group-containing monomer is, in moles, about 5% to about 20%, about 5% to about 15%, about 5% to about 10%, about 6% to about 20%, about 7% to about 20%, about 8% to about 20%, about 9% to about 20%, about 10% to about 20%, about 10% to about 19%, about 10% to about 18%, about 10% to about 17%, about 10% to about 16%, about 10% to about 15%, about 8% to about 17%, about 7% to about 13%, about 12% to about 18%, or about 15% to about 20%, based on the total number of moles of monomers in the composition.

[0097] In some embodiments, the proportion of the amide group-containing monomer is, in moles, 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%, or less than 6%, based on the total number of moles of monomers in the composition. In some embodiments, the proportion of the amide group-containing monomer is, in moles, more than 5%, more than 6%, more than 7%, more than 8%, more than 9%, more than 10%, more than 11%, more than 12%, more than 13%, more than 14%, more than 15%, more than 16%, more than 17%, more than 18%, or more than 19%, based on the total number of moles of monomers in the composition.

[0098] In some embodiments, each of the second suspension, the third suspension, and the fourth suspension is independently 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.

[0099] In some embodiments, each of the second suspension, the third suspension, and the fourth suspension is independently 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, each of the second suspension, the third suspension, and the fourth suspension is independently stirred at a speed faster than 20 rpm, faster than 40 rpm, faster than 60 rpm, faster than 80 rpm, faster than 100 rpm, faster than 120 rpm, faster than 140 rpm, faster than 160 rpm, faster than 180 rpm, faster than 200 rpm, faster than 220 rpm, faster than 240 rpm, faster than 260 rpm, or faster than 280 rpm.

[0100] In some embodiments, each of the second suspension, the third suspension, and the fourth suspension is independently stirred for a time of about 30 minutes to about 120 minutes, about 30 minutes to about 105 minutes, about 30 minutes to about 90 minutes, about 45 minutes to about 90 minutes, about 45 minutes to about 75 minutes, about 50 minutes to about 70 minutes, or about 40 minutes to about 80 minutes. In some embodiments, each of the second suspension, the third suspension, and the fourth suspension is independently stirred for a time 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, or less than 40 minutes. In some embodiments, each of the second suspension, the third suspension, and the fourth suspension is independently stirred for a time longer than 30 minutes, longer than 40 minutes, longer than 50 minutes, longer than 60 minutes, longer than 70 minutes, longer than 80 minutes, longer than 90 minutes, longer than 100 minutes, or longer than 110 minutes.

[0101] In some embodiments, the initiator solution is prepared by dissolving an initiator in water. In some embodiments, the fifth suspension is formed by dropwise adding the initiator solution to the fourth suspension in step 105.

[0102] In some embodiments, the temperature of the fourth suspension is raised 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 before adding the initiator solution to the fourth suspension to form the fifth suspension.

[0103] In some embodiments, the temperature of the fourth suspension is raised 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 before adding the initiator solution to the fourth suspension to form the fifth suspension. In some embodiments, the temperature of the fourth suspension is raised to higher than 30°C, higher than 32°C, higher than 34°C, higher than 36°C, higher than 38°C, higher than 40°C, higher than 42°C, higher than 44°C, higher than 46°C, higher than 48°C, higher than 50°C, higher than 52°C, higher than 54°C, higher than 56°C, higher than 58°C, higher than 60°C, higher than 62°C, higher than 64°C, or higher than 66°C before adding the initiator solution to the fourth suspension to form the fifth suspension.

[0104] In some embodiments, the fourth suspension is stirred at a speed of about 50 rpm to about 500 rpm, about 50 rpm to about 450 rpm, about 50 rpm to about 400 rpm, about 50 rpm to about 350 rpm, about 50 rpm to about 300 rpm, about 50 rpm to about 280 rpm, about 50 rpm to about 260 rpm, about 50 rpm to about 240 rpm, about 50 rpm to about 220 rpm, about 50 rpm to about 200 rpm, about 50 rpm to about 180 rpm, about 50 rpm to about 160 rpm, about 50 rpm to about 140 rpm, about 50 rpm to about 120 rpm, or about 50 rpm to about 100 rpm before adding the initiator solution to the fourth suspension to form the fifth suspension.

[0105] In some embodiments, the fourth suspension is stirred at a speed of 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, or less than 100 rpm before adding the initiator solution to the fourth suspension to form the fifth suspension. In some embodiments, the fourth suspension is stirred at a speed 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, or greater than 450 rpm before adding the initiator solution to the fourth suspension to form the fifth suspension.

[0106] In some embodiments, the fourth suspension is stirred for a time of about 30 minutes to about 120 minutes, about 30 minutes to about 105 minutes, about 30 minutes to about 90 minutes, about 45 minutes to about 90 minutes, about 45 minutes to about 75 minutes, about 50 minutes to about 70 minutes, or about 40 minutes to about 80 minutes before adding the initiator solution to the fourth suspension to form the fifth suspension. In some embodiments, the fourth suspension is stirred for a time 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, or less than 40 minutes before adding the initiator solution to the fourth suspension to form the fifth suspension. In some embodiments, the fourth suspension is stirred for a time longer than 30 minutes, longer than 40 minutes, longer than 50 minutes, longer than 60 minutes, longer than 70 minutes, longer than 80 minutes, longer than 90 minutes, longer than 100 minutes, or longer than 110 minutes before adding the initiator solution to the fourth suspension to form the fifth suspension.

[0107] The polymerization occurring in the present invention follows a radical mechanism in which the initiator acts to generate free radicals, which leads 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.

[0108] Water-soluble free radical initiators thermally decompose in the aqueous phase to give radicals that can initiate polymerization. In some embodiments, the water-soluble initiator can be selected from the group consisting of persulfate-based initiators such as ammonium persulfate, sodium persulfate, potassium persulfate, azo-based 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 salt, 2,2'-azobis(N-2'-methylpropanoyl-2-aminoalkyl-1 ) -sulfone acid, etc. and peroxide-based initiators such as hydrogen peroxide, t-butyl hydroperoxide, succinic peroxide and combinations thereof.

[0109] In some embodiments, the water-soluble free radical initiator can be used together with a reducing agent to establish a redox initiator system. This enables the generation of free radicals by an oxidation-reduction reaction at a relatively low temperature, promoting an increase in the polymerization rate.

[0110] 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, ferric chloride, ascorbic acid, citric acid, tartaric acid, erythorbic acid, glucose , pho rumm aldehyde sulfoxylate metal salts, burgolite FF6M , and and combinations thereof.

[0111] In some embodiments, the proportion of the water-soluble free radical initiator is, by weight, about 0.05% to about 0.4%, about 0.07% to about 0.4%, about 0.1% to about 0.4%, about 0.1% to about 0.39%, about 0.1% to about 0.38%, about 0.1% to about 0.37%, about 0.1% to about 0.36%, about 0.1% to about 0.35%, about 0.1% to about 0.34%, about 0.1% to about 0.33%, about 0.1% to about 0.32%, about 0.1% to about 0.31%, about 0.1% to about 0.3%, about 0.1% to about 0.29%, about 0.1% to about 0.28%, about 0.1% to about 0.27%, or about 0.1% to about 0.26%, based on the total weight of the monomers added in the preparation of the binder composition. When the proportion of the water-soluble initiator in the total weight of the monomers added in the preparation of 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.

[0112] In some embodiments, the proportion of the water-soluble initiator is less than 0.4%, less than 0.38%, less than 0.36%, less than 0.34%, less than 0.32%, less than 0.3%, less than 0.28%, less than 0.26%, less than 0.24%, less than 0.22%, less than 0.2%, less than 0.18%, less than 0.16%, less than 0.14%, less than 0.12%, less than 0.1%, or less than 0.08% by weight, based on the total weight of the monomers added in the preparation of the binder composition. In some embodiments, the proportion of the water-soluble initiator is more than 0.05%, more than 0.07%, more than 0.1%, more than 0.12%, more than 0.14%, more than 0.16%, more than 0.18%, more than 0.2%, more than 0.22%, more than 0.24%, more than 0.26%, more than 0.28%, more than 0.3%, more than 0.32%, more than 0.34%, more than 0.36%, or more than 0.38% by weight, based on the total weight of the monomers added in the preparation of the binder composition.

[0113] In some embodiments, the proportion of the reducing agent is, by weight, about 0.01% to about 0.2%, about 0.02% to about 0.2%, about 0.03% to about 0.2%, about 0.04% to about 0.2%, about 0.05% to about 0.2%, about 0.06% to about 0.2%, about 0.07% to about 0.2%, about 0.08% to about 0.2%, about 0.09% to about 0.2%, or about 0.1% to about 0.2%, based on the total weight of the monomers added in the preparation of the binder composition.

[0114] In some embodiments, the proportion of the reducing agent is, by weight, 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%, or less than 0.04%, based on the total weight of the monomers added in the preparation of the binder composition. In some embodiments, the proportion of the reducing agent is, by weight, more than 0.01%, more than 0.02%, more than 0.03%, more than 0.04%, more than 0.05%, more than 0.06%, more than 0.07%, more than 0.08%, more than 0.09%, more than 0.1%, more than 0.11%, more than 0.12%, more than 0.13%, more than 0.14%, more than 0.15%, or more than 0.16%, based on the total weight of the monomers added in the preparation of the binder composition.

[0115] In some embodiments, when a redox initiator system is selected as the initiator, the molar ratio of the water-soluble free radical initiator to the 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.

[0116] In some embodiments, when a redox initiator system is selected as the initiator, the molar ratio of the water-soluble free radical initiator to the 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 、2 . 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 the water-soluble free radical initiator to the reducing agent is more than 0.2, more than 0.4, more than 0.6, more than 0.8, more than 1, more than 1.2, more than 1.4, more than 1.6, more than 1.8, more than 2, more than 2.2, more than 2.4, more than 2.6, more than 2.8, more than 3, more than 3.2, more than 3.4, more than 3.6, more than 3.8, more than 4, more than 4.2, more than 4.4, more than 4.6, more than 4.8, more than 5, more than 6, more than 7, more than 8, or more than 9.

[0117] In some embodiments, the reducing agent solution is prepared by dissolving the reducing agent in water. In some embodiments, when a redox initiator system is selected as the initiator, the reducing agent is added to the fourth suspension before the addition of the initiator solution, and a fifth suspension is formed.

[0118] In some embodiments, the initiator solution is added dropwise to the fourth suspension over a time period of about 2 hours to about 5 hours, about 2 hours to about 4.75 hours, about 2 hours to about 4.5 hours, about 2 hours to about 4.25 hours, about 2 hours to about 4 hours, about 2 hours to about 3.75 hours, about 2 hours to about 3.5 hours, about 2.25 hours to about 3.5 hours, or about 2.5 hours to about 3.5 hours. In some embodiments, the initiator solution is added dropwise to the fourth suspension over a time period of 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, or less than 2.5 hours. In some embodiments, the initiator solution is added dropwise to the fourth suspension over a time period longer than 2 hours, longer than 2.25 hours, longer than 2.5 hours, longer than 2.75 hours, longer than 3 hours, longer than 3.25 hours, longer than 3.5 hours, longer than 3.75 hours, longer than 4 hours, longer than 4.25 hours, or longer than 4.5 hours.

[0119] The polymerization temperature depends on the type of initiator applied. In some embodiments, the reaction temperature of the polymerization 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 reaction temperature of the polymerization is within the above range, higher reaction stability can be achieved and the binder composition can exhibit better overall binding performance.

[0120] 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 higher than 50°C, higher than 52°C, higher than 54°C, higher than 56°C, higher than 58°C, higher than 60°C, higher than 62°C, higher than 64°C, higher than 66°C, higher than 68°C, higher than 70°C, higher than 72°C, higher than 74°C, higher than 76°C, higher than 78°C, higher than 80°C, higher than 82°C, higher than 84°C, or higher than 86°C.

[0121] In some embodiments, the stirring speed of the mixer during polymerization is from about 100 rpm to about 1000 rpm, from about 100 rpm to about 950 rpm, from about 100 rpm to about 900 rpm, from about 100 rpm to about 850 rpm, from about 100 rpm to about 800 rpm, from about 100 rpm to about 750 rpm, from about 100 rpm to about 700 rpm, from about 100 rpm to about 650 rpm, from about 100 rpm to about 600 rpm, from about 100 rpm to about 550 rpm, from about 100 rpm to about 500 rpm, from about 150 rpm to about 500 rpm, from about 200 rpm to about 500 rpm, from about 250 rpm to about 500 rpm, from about 250 rpm to about 450 rpm, from about 300 rpm to about 450 rpm, or from about 300 rpm to about 400 rpm. In some embodiments, the stirring speed of the mixer during polymerization is less than 1000 rpm, less than 950 rpm, less than 900 rpm, less than 850 rpm, less than 800 rpm, less than 750 rpm, less than 700 rpm, less than 650 rpm, less than 600 rpm, less than 550 rpm, less than 500 rpm, less than 450 rpm 、4Less than 00 rpm, less than 350 rpm, less than 300 rpm, less than 250 rpm, less than 200 rpm, or less than 150 rpm. In some embodiments, the stirring speed of the mixer during polymerization is faster than 100 rpm, faster than 150 rpm, faster than 200 rpm, faster than 250 rpm, faster than 300 rpm, faster than 350 rpm, faster than 400 rpm, faster than 450 rpm, faster than 500 rpm, faster than 550 rpm, faster than 600 rpm, faster than 650 rpm, faster than 700 rpm, faster than 750 rpm, faster than 800 rpm, faster than 850 rpm, faster than 900 rpm, or faster than 950 rpm.

[0122] In some embodiments, the reaction time of the polymerization is from about 20 hours to about 24 hours, from about 20.25 hours to about 24 hours, from about 20.5 hours to about 24 hours, from about 20.75 hours to about 24 hours, from about 21 hours to about 24 hours, from about 21.25 hours to about 24 hours, from about 21.5 hours to about 24 hours, from about 21.75 hours to about 24 hours, from about 22 hours to about 24 hours, from about 20 hours to about 23.75 hours, from about 20 hours to about 23.5 hours, from about 20 hours to about 23.25 hours, from about 20 hours to about 23 hours, from about 20 hours to about 22.75 hours, from about 20 hours to about 22.5 hours, from about 20 hours to 22.25 hours, from about 20 hours to 22 hours, or from about 22 hours to about 23 hours.

[0123] In some embodiments, the reaction time of the polymerization is less than 24 hours, less than 23.75 hours, less than 23.5 hours, less than 23.25 hours, less than 23 hours, less than 22.75 hours, less than 22.5 hours, less than 22.25 hours, less than 22 hours, less than 21.75 hours, less than 21.5 hours, less than 21.25 hours, less than 21 hours, less than 20.75 hours, less than 20.5 hours, or less than 20.25 hours. In some embodiments, the reaction time of the polymerization is longer than 20 hours, longer than 20.25 hours, longer than 20.5 hours, longer than 20.75 hours, longer than 21 hours, longer than 21.25 hours, longer than 21.5 hours, longer than 21.75 hours, longer than 22 hours, longer than 22.25 hours, longer than 22.5 hours, longer than 22.75 hours, longer than 23 hours, longer than 23.25 hours, longer than 23.5 hours, or longer than 23.75 hours.

[0124] In some embodiments, the fifth suspension is stirred for a time of about 22 hours to about 30 hours, about 22 hours to about 29.5 hours, about 22 hours to about 29 hours, about 22 hours to about 28.5 hours, about 22 hours to about 28 hours, about 22.5 hours to about 28 hours, about 23 hours to about 28 hours, about 23.5 hours to about 28 hours, about 24 hours to about 28 hours, about 24 hours to about 27.5 hours, about 24 hours to about 27 hours, about 24.5 hours to about 27 hours, about 25 hours to about 27 hours, about 24 hours to about 26 hours, or about 26 hours to about 28 hours during the addition of the initiator solution and when the polymerization is carried out.

[0125] In some embodiments, the fifth suspension is stirred for a time of less than 30 hours, less than 29.5 hours, less than 29 hours, less than 28.5 hours, 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, or less than 22.5 hours during the addition of the initiator solution and during polymerization. In some embodiments, the fifth suspension is stirred for a time longer than 22 hours, longer than 22.5 hours, longer than 23 hours, longer than 23.5 hours, longer than 24 hours, longer than 24.5 hours, longer than 25 hours, longer than 25.5 hours, longer than 26 hours, longer than 26.5 hours, longer than 27 hours, longer than 27.5 hours, longer than 28 hours, longer than 28.5 hours, longer than 29 hours, or longer than 29.5 hours during the addition of the initiator solution and during polymerization.

[0126] In some embodiments, the neutralization solution is prepared by dissolving a neutralizing agent in water. In some embodiments, the sixth suspension is formed by adding the neutralization solution to the fifth suspension in step 106. The above-mentioned neutralizing agent 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.

[0127] In some embodiments, the temperature of the fifth suspension is reduced to about 40°C to about 50°C, about 40°C to about 49°C, about 40°C to about 48°C, about 40°C to about 47°C, about 40°C to about 46°C, about 40°C to about 45°C, about 41°C to about 50°C, about 42°C to about 50°C, about 43°C to about 50°C, about 44°C to about 50°C, about 45°C to about 50°C, or about 42°C to about 48°C before adding the neutralizing solution to form the sixth suspension. In some embodiments, the temperature of the fifth suspension is reduced to less than 50°C, less than 49°C, less than 48°C, less than 47°C, less than 46°C, less than 45°C, less than 44°C, less than 43°C, less than 42°C, or less than 41°C before adding the neutralizing solution to form the sixth suspension. In some embodiments, the temperature of the fifth suspension is reduced to higher than 40°C, higher than 41°C, higher than 42°C, higher than 43°C, higher than 44°C, higher than 45°C, higher than 46°C, higher than 47°C, higher than 48°C, or higher than 49°C before adding the neutralizing solution to form the sixth suspension.

[0128] In some embodiments, the total proportion of the neutralizing agent is, in moles, about 10% to about 40%, about 10% to about 38%, about 10% to about 36%, about 10% to about 34%, about 10% to about 32%, about 10% to about 30%, about 10% to about 28%, about 10% to about 26%, about 10% to about 25.5%, about 10% to about 25%, about 10% to about 24.5%, about 10% to about 24%, about 10% to about 23.5%, about 10% to about 23%, about 10% to about 22.5%, about 10% to about 22%, about 10% to about 21.5%, about 10% to about 21%, about 10% to about 20.5%, about 10% to about 20%, about 10% to about 19.5%, about 10% to about 19%, about 10% to about 18.5%, about 10% to about 18%, about 17.5%, about 10% to about 17%, about 10% to about 16.5%, about 10% to about 16%, about 10% to about 15.5%, about 10% to about 15%, about 10.5% to about 19%, about 11% to about 19%, or about 11% to about 15% based on the total number of moles of the monomer units in the copolymer in the binder composition.

[0129] In some embodiments, the total proportion of the neutralizing agent is less than 40 mol%, less than 38 mol%, less than 36 mol%, less than 34 mol%, less than 32 mol%, less than 30 mol%, less than 29 mol%, less than 28 mol%, less than 27 mol%, less than 26 mol%, less than 25 mol%, less than 24 mol%, less than 23 mol%, less than 22 mol%, less than 21 mol%, less than 20 mol%, less than 19 mol%, less than 18 mol%, less than 17 mol%, less than 16 mol%, less than 15 mol%, less than 14 mol%, less than 13 mol%, less than 12 mol%, or less than 11 mol% in terms of moles, based on the total number of moles of monomer units in the copolymer in the binder composition. In some embodiments, the total proportion of the neutralizing agent is more than 10 mol%, more than 11 mol%, more than 12 mol%, more than 13 mol%, more than 14 mol%, more than 15 mol%, more than 16 mol%, more than 17 mol%, more than 18 mol%, more than 19 mol%, more than 20 mol%, more than 21 mol%, more than 22 mol%, more than 23 mol%, more than 24 mol%, more than 25 mol%, more than 26 mol%, more than 28 mol%, more than 30 mol%, more than 32 mol%, more than 34 mol%, more than 36 mol%, or more than 38 mol% in terms of moles, based on the total number of moles of monomer units in the copolymer in the binder composition.

[0130] In some embodiments, the sixth suspension is stirred for a time of 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, about 2.5 hours to about 3.5 hours, about 2.75 hours to about 3.5 hours, about 2.75 hours to about 3.25 hours, about 2.5 hours to about 3 hours, about 2 hours to about 3 hours, about 3 hours to about 3.5 hours, or about 3 hours to about 4 hours. In some embodiments, the sixth suspension is stirred for a time 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, less than 1.5 hours, or less than 1.25 hours. In some embodiments, the sixth suspension is stirred for a time longer than 1 hour, longer than 1.25 hours, longer than 1.5 hours, longer than 1.75 hours, longer than 2 hours, longer than 2.25 hours, longer than 2.5 hours, longer than 2.75 hours, longer than 3 hours, longer than 3.25 hours, longer than 3.5 hours, or longer than 3.75 hours.

[0131] In some embodiments, the temperature of the sixth suspension is reduced to 20°C to about 35°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, about 25°C to about 35°C, about 26°C to about 35°C, about 27°C to about 35°C, about 28°C to about 35°C, about 29°C to about 35°C, about 30°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 20°C to about 29°C, about 20°C to about 28°C, about 20°C to about 27°C, or about 25°C to about 30°C. In some embodiments, the temperature of the sixth suspension is reduced to 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. In some embodiments, the temperature of the sixth suspension is reduced to higher than 20°C, higher than 21°C, higher than 22°C, higher than 23°C, higher than 24°C, higher than 25°C, higher than 26°C, higher than 27°C, higher than 28°C, higher than 29°C, higher than 30°C, higher than 31°C, higher than 32°C, higher than 33°C, or higher than 34°C.

[0132] In some embodiments, by filtering the sixth suspension in step 107, a binder composition is formed.

[0133] Filtration aims to remove precipitates or unconverted monomers present in the suspension in order to obtain a well-dispersed binder composition. The polymerization step in the production of a binder composition containing both structural units (a1) and (a2) respectively derived from a first carboxylic acid group-containing monomer and a second carboxylic acid group-containing monomer can achieve a yield of 95% or more (Examples 4 to 23), and it has been confirmed that the retention during filtration is extremely small. On the other hand, when only one carboxylic acid group-containing monomer is employed in the polymerization step (Examples 1 to 3, 24, 25), the monomer conversion rate is 60 to 80%. This means that there is a significant amount of unconverted monomer, which is likely to result in high costs regardless of the recovery and reuse of the unconverted monomer. However, when only one type of carboxylic acid group-containing monomer is applied, although the monomer conversion rate is low, the ratio of the constituent structural units falls within the range disclosed herein. Also, in the production of a binder composition consisting only of the structural unit (a) derived from a carboxylic acid group-containing monomer, precipitation of unwanted by-products, presumably due to the formation of a relatively unstable copolymer system, is observed.

[0134] The addition of the neutralizing agent in Steps 101 and 106 aims to neutralize the carboxylic acid group-containing monomer added in Step 102 and produce an inherently weakly alkaline binder composition. Exposing the binder composition to acidic conditions is not preferred as it may disrupt the dispersion of the binder composition.

[0135] In some embodiments, the structural unit (a) derived from a carboxylic acid group-containing monomer contains a carboxylate group. In some embodiments, the carboxylate 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 group and a carboxylic acid group. In some embodiments, the structural unit (a) contains an alkali metal carboxylate group. Examples of alkali metals forming alkali metal carboxylates include lithium, sodium, and potassium. In some embodiments, the structural unit (a) contains an ammonium carboxylate group.

[0136] In some embodiments, the structural unit (a1) derived from the first carboxylic acid group-containing monomer contains a carboxylate group. In some embodiments, the carboxylate group is a salt of a carboxylic acid group. In some embodiments, the structural unit (a1) derived from the first carboxylic acid group-containing monomer contains a combination of a carboxylate group and a carboxylic acid group. In some embodiments, the structural unit (a1) contains an alkali metal carboxylate group. Examples of the alkali metal forming the alkali metal carboxylate include lithium, sodium, and potassium. In some embodiments, the structural unit (a1) contains an ammonium carboxylate group.

[0137] In some embodiments, the structural unit (a2) derived from the second carboxylic acid group-containing monomer contains a carboxylate group. In some embodiments, the carboxylate group is a salt of a carboxylic acid group. In some embodiments, the structural unit (a2) derived from the second carboxylic acid group-containing monomer contains a combination of a carboxylate group and a carboxylic acid group. In some embodiments, the structural unit (a2) contains an alkali metal carboxylate group. Examples of the alkali metal forming the alkali metal carboxylate include lithium, sodium, and potassium. In some embodiments, the structural unit (a2) contains an ammonium carboxylate group.

[0138] In some embodiments, when the copolymer contains the structural unit (a), the molar ratio of the carboxylic acid group to the carboxylate group in the copolymer is about 0 to about 0.25, about 0 to about 0.24, about 0 to about 0.23, about 0 to about 0.22, about 0 to about 0.21, about 0 to about 0.2, about 0 to about 0.19, about 0 to about 0.18, about 0 to about 0.17, about 0 to about 0.16, about 0 to about 0.15, about 0 to about 0.14, about 0 to about 0.13, about 0 to about 0.12, about 0 to about 0.11, about 0 to about 0.1, about 0 to about 0.09, about 0 to about 0.08, about 0 to about 0.07, about 0 to about 0.06, or about 0 to about 0.05.

[0139] In some embodiments, when the copolymer contains structural unit (a), the molar ratio of carboxylic acid groups to carboxylate groups in the copolymer is less than 0.25, less than 0.24, less than 0.23, less than 0.22, less than 0.21, less than 0.2, less than 0.18, less than 0.16, less than 0.14, less than 0.12, less than 0.1, less than 0.08, less than 0.06, less than 0.04, or less than 0.02. In some embodiments, the molar ratio of carboxylic acid groups to carboxylate groups in the copolymer is more than 0, more than 0.02, more than 0.04, more than 0.06, more than 0.08, more than 0.1, more than 0.12, more than 0.14, more than 0.16, more than 0.18, more than 0.2, more than 0.22, or more than 0.24.

[0140] In one embodiment, when the copolymer contains structural unit (a1) and structural unit (a2), the molar ratio of carboxylic acid groups to carboxylate groups in the copolymer is from about 0 to about 0.25, from about 0 to about 0.24, from about 0 to about 0.23, from about 0 to about 0.22, from about 0 to about 0.21, 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 0.12, 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, or from about 0 to about 0.05.

[0141] In some embodiments, when the copolymer comprises structural unit (a1) and structural unit (a2), the molar ratio of carboxylic acid groups to carboxylate groups in the copolymer is less than 25, less than 0.24, less than 0.23, less than 0.22, less than 0.21, less than 0.2, less than 0.18, less than 0.16, less than 0.14, less than 0.12, less than 0.1, less than 0.08, less than 0.06, less than 0.04, or less than 0.02. In some embodiments, when the copolymer comprises structural unit (a1) and structural unit (a2), the molar ratio of carboxylic acid groups to carboxylate groups in the copolymer is more than 0, more than 0.02, more than 0.04, more than 0.06, more than 0.08, more than 0.1, more than 0.12, more than 0.14, more than 0.16, more than 0.18, more than 0.2, more than 0.22, or more than 0.24.

[0142] In some embodiments, the proportion of structural unit (a) in the copolymer, based on the total number of monomer units in the copolymer in the binder composition, is about 7% to about 25%, about 8% to about 25%, about 9% to about 25%, about 10% to about 25%, about 10% to about 24%, about 10% to about 23%, about 10% to about 22%, about 10% to about 21%, about 10% to about 20%, about 10% to about 19%, about 10% to about 18%, about 10% to about 17%, about 10% to about 16%, about 10% to about 15%, about 12% to about 25%, about 12% to about 20%, or about 12% to about 18% in moles.

[0143] In some embodiments, the proportion of structural unit (a) in the copolymer is 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%, or less than 8% in moles, based on the total number of moles of monomer units in the copolymer in the binder composition. In some embodiments, the proportion of structural unit (a) in the copolymer is more than 7%, more than 8%, more than 9%, more than 10%, more than 11%, more than 12%, more than 13%, more than 14%, more than 15%, more than 16%, more than 17%, more than 18%, more than 19%, more than 20%, more than 21%, more than 22%, more than 23%, or more than 24% in moles, based on the total number of moles of monomer units in the copolymer in the binder composition.

[0144] In some embodiments, when the copolymer contains structural unit (a1) and structural unit (a2), the proportion of structural unit (a1) in the copolymer is about 4% to about 25%, about 5% to about 25%, about 6% to about 25%, about 7% to about 25%, about 8% to about 25%, about 9% to about 25%, about 10% to about 25%, about 10% to about 24%, about 10% to about 23%, about 10% to about 22%, about 10% to about 21%, about 10% to about 20%, about 10% to about 19%, about 10% to about 18%, about 10% to about 17%, about 10% to about 16%, about 10% to about 15%, about 8% to about 25%, about 8% to about 20%, about 8% to about 18%, or about 8% to about 15% in moles, based on the total number of moles of monomer units in the copolymer of the binder composition.

[0145] In some embodiments, when the copolymer comprises structural unit (a1) and structural unit (a2), the proportion of structural unit (a1) in the copolymer is 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%, or less than 5% in moles, based on the total number of moles of monomer units in the copolymer in the binder composition. In some embodiments, when the copolymer comprises structural unit (a1) and structural unit (a2), the proportion of structural unit (a1) in the copolymer is more than 4%, more than 5%, more than 6%, more than 7%, more than 8%, more than 9%, more than 10%, more than 11%, more than 12%, more than 13%, more than 14%, more than 15%, more than 16%, more than 17%, more than 18%, more than 19%, more than 20%, more than 21%, more than 22%, more than 23%, or more than 24% in moles, based on the total number of moles of monomer units of the copolymer in the binder composition.

[0146] In some embodiments, when the copolymer comprises structural unit (a1) and structural unit (a2), the proportion of structural unit (a2) in the copolymer is about 1% to about 4.5%, about 1% to about 4.4%, about 1% to about 4.3%, about 1% to about 4.2%, about 1% to about 4.1%, about 1% to 4%, about 1.1% to about 4%, about 1.2% to 4%, about 1.3% to about 4%, about 1.4% to about 4%, about 1.5% to about 4.5%, about 1.5% to about 4%, or about 2% to about 4.5% in moles, based on the total number of moles of monomer units in the copolymer of the binder composition.

[0147] In some embodiments, when the copolymer comprises structural unit (a1) and structural unit (a2), the proportion of structural unit (a2) in the copolymer is less than 4.5 mol%, less than 4.4 mol%, less than 4.2 mol%, less than 4 mol%, less than 3.8 mol%, less than 3.6 mol%, less than 3.4 mol%, less than 3.2 mol%, less than 3 mol%, less than 2.8 mol%, less than 2.6 mol%, less than 2.4 mol%, less than 2.2 mol%, less than 2 mol%, less than 1.8 mol%, less than 1.6 mol%, or less than 1.4 mol% based on the total number of moles of monomer units in the copolymer of the binder composition. In some embodiments, when the copolymer comprises structural unit (a1) and structural unit (a2), the proportion of structural unit (a2) in the copolymer is more than 1 mol%, more than 1.2 mol%, more than 1.4 mol%, more than 1.6 mol%, more than 1.8 mol%, more than 2 mol%, more than 2.2 mol%, more than 2.4 mol%, more than 2.6 mol%, more than 2.8 mol%, more than 3 mol%, more than 3.2 mol%, more than 3.4 mol%, more than 3.6 mol%, more than 3.8 mol%, more than 4 mol%, more than 4.2 mol%, or more than 4.4 mol% based on the total number of moles of monomer units of the copolymer of the binder composition.

[0148] In some embodiments, when the copolymer comprises structural unit (a1) and structural unit (a2), the molar ratio of structural unit (a1) to structural unit (a2) in the copolymer is from about 1 to about 12, from about 1 to about 11.5, from about 1 to about 11, from about 1 to about 10.5, from about 1 to about 10, from about 1 to about 9.5, from about 1 to about 9, from about 1 to about 8.5, from about 1 to about 8, from about 1 to about 7.5, from about 1 to about 7, from about 1 to about 6.5, from about 1 to about 6, from 1.5 to about 6, from 2 to about 6, from 2 to about 10, from 2 to about 8, from 2.5 to about 10, from 2.5 to about 8, from 3 to about 10, or from 3 to about 8.

[0149] In some embodiments, when the copolymer contains structural unit (a1) and structural unit (a2), the molar ratio of structural unit (a1) to structural unit (a2) in the copolymer is less than 12, less than 11.5, less than 11, less than 10.5, less than 10, less than 9.5, less than 9, less than 8.5, less than 8, less than 7.5, less than 7, less than 6.5, less than 6, less than 5.5, less than 5, less than 4.5, less than 4, less than 3.5, less than 3, less than 2.5, or less than 2. In some embodiments, when the copolymer contains structural unit (a1) and structural unit (a2), the molar ratio of structural unit (a1) to structural unit (a2) in the copolymer is more than 1, more than 1.5, more than 2, more than 2.5, more than 3, more than 3.5, more than 4, more than 4.5, more than 5, more than 5.5, more than 6, more than 6.5, more than 7, more than 7.5, more than 8, more than 8.5, more than 9, more than 9.5, more than 10, more than 10.5, or more than 11.

[0150] In some embodiments, the proportion of structural unit (b) in the copolymer is about 4% to about 17%, about 4% to about 15%, about 4% to about 10%, about 5% to about 17%, about 6% to about 17%, about 7% to about 17%, about 8% to about 17%, about 9% to about 17%, about 10% to about 17%, about 10% to about 16%, about 10% to about 15%, about 8% to about 13%, about 7% to about 13%, about 12% to about 17%, or about 13% to about 17% in moles, based on the total number of moles of monomer units in the copolymer in the binder composition.

[0151] In some embodiments, the proportion of structural unit (b) in the copolymer is 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%, or less than 5% in moles, based on the total number of moles of monomer units in the copolymer in the binder composition. In some embodiments, the proportion of structural unit (b) in the copolymer is more than 4%, more than 5%, more than 6%, more than 7%, more than 8%, more than 9%, more than 10%, more than 11%, more than 12%, more than 13%, more than 14%, more than 15%, or more than 16% in moles, based on the total number of moles of monomer units in the copolymer in the binder composition.

[0152] In some embodiments, the proportion of structural unit (c) in the copolymer is about 65% to about 80%, about 65.5% to about 80%, about 66% to about 80%, about 66.5% to about 80%, about 67% to about 80%, about 67.5% to about 80%, about 68% to about 80%, about 68.5% to about 80%, about 69% to 80%, about 69.5% to about 80%, about 70% to 80%, about 70% to about 79.5%, about 70% to about 79%, about 70% to about 78.5%, about 70% to about 78%, about 70% to about 77.5%, about 70% to about 77%, about 70% to about 76.5%, about 70% to about 76%, about 70.5% to about 76%, about 71% to about 76%, about 71.5% to about 76%, about 72% to about 76%, about 67% to about 77%, or about 68% to about 75% in moles, based on the total number of moles of monomer units in the copolymer in the binder composition.

[0153] In some embodiments, the proportion of structural unit (c) in the copolymer is more than 65%, more than 66%, more than 67%, more than 68%, more than 69%, more than 70%, more than 71%, more than 72%, more than 73%, more than 74%, more than 75%, more than 76%, more than 77%, more than 78%, or more than 79% in moles, based on the total number of moles of monomer units in the copolymer in the binder composition. In some embodiments, the proportion of structural unit (c) in the copolymer is less than 80%, less than 79% 、7 less than 78%, less than 77%, less than 76%, less than 75%, less than 74%, less than 73%, less than 72%, less than 71%, less than 70%, less than 69%, less than 68%, less than 67%, or less than 66% in moles, based on the total number of moles of monomer units in the copolymer in the binder composition.

[0154] In some embodiments, structural unit (a) and structural unit (b) are configured as the hydrophilic part of the copolymer. In some embodiments, structural unit (a1), structural unit (a2) and structural unit (b) are configured as the hydrophilic part of the copolymer. In some embodiments, structural unit (c) is configured as the hydrophobic part of the copolymer.

[0155] In some embodiments, the total proportion of structural unit (a) and structural unit (b) in the copolymer is about 18% to about 35%, about 18.5% to about 35%, about 19% to about 35%, about 19.5% to about 35%, about 20% to about 35%, about 20% to about 34.5%, about 20% to about 34%, about 20% to 33.5%, about 20% to 33%, about 20% to about 32.5%, about 20% to about 32%, about 20% to about 31.5%, about 20% to about 31%, about 20% to about 30.5%, about 20% to about 30%, about 20.5% to about 30%, about 21% to about 30%, about 21.5% to about 30%, about 22% to about 30%, about 22% to about 32%, about 25% to about 35%, or about 25% to about 30% in moles, based on the total number of moles of monomer units in the copolymer in the binder composition.

[0156] In some embodiments, the proportion of the sum of structural unit (a) and structural unit (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%, or less than 19% in terms of mole, based on the total number of moles of monomer units in the copolymer in the binder composition. In some embodiments, the proportion of the sum of structural unit (a) and structural unit (b) in the copolymer is more than 18%, more than 19%, more than 20%, more than 21%, more than 22%, more than 23%, more than 24%, more than 25%, more than 26%, more than 27%, more than 28%, more than 29%, more than 30%, more than 31%, more than 32%, more than 33%, or more than 34% in terms of mole, based on the total number of moles of monomer units in the copolymer in the binder composition.

[0157] In some embodiments, the total proportion of structural unit (a1), structural unit (a2) and structural unit (b) in the copolymer is about 18% to about 35%, about 18.5% to about 35%, about 19% to about 35%, about 19.5% to about 35%, about 20% to about 35%, about 20% to about 34.5%, about 20% to about 34%, about 20% to about 33.5%, about 20% to about 33%, about 20% to about 32.5%, about 20% to about 32%, about 20% to about 31.5%, about 20% to about 31%, about 20% to about 30.5%, about 20% to about 30%, about 20.5% to about 30%, about 21% to about 30%, about 21.5% to about 30%, about 22% to about 30%, about 22% to about 32%, about 25% to about 35%, or about 25% to about 30% in terms of mole, based on the total number of moles of monomer units in the copolymer of the binder composition.

[0158] In some embodiments, the total proportion of structural unit (a1), structural unit (a2), and structural unit (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%, or less than 19% in moles, based on the total number of moles of monomer units in the copolymer in the binder composition. In some embodiments, the total proportion of structural unit (a1), structural unit (a2), and structural unit (b) in the copolymer is more than 18%, more than 19%, more than 20%, more than 21%, more than 22%, more than 23%, more than 24%, more than 25%, more than 26%, more than 27%, more than 28%, more than 29%, more than 30%, more than 31%, more than 32%, more than 33%, or more than 34% in moles, based on the total number of moles of monomer units in the copolymer in the binder composition.

[0159] In some embodiments, the molar ratio of structural unit (c) to the total of structural unit (a) and structural unit (b) in the copolymer is from about 1.5 to about 4, from about 1.6 to about 4, from about 1.7 to about 4, from about 1.8 to about 4, from about 1.9 to about 4, from about 2 to about 4, from about 2 to about 3.9, from about 2 to about 3.8, from about 2 to about 3.7, from about 2 to about 3.6, from about 2 to about 3.5, from about 2 to about 3.4, from about 2 to about 3.3, from about 2 to about 3.2, from about 2 to about 3.1, from about 2 to about 3, from about 2.2 to about 3.5, or from about 2.4 to about 3.8.

[0160] In some embodiments, the molar ratio of structural unit (c) to the sum of structural units (a) and (b) in the copolymer is less than 4, less than 3.9, less than 3.8, less than 3.7, less than 3.6, less than 3.5, less than 3.4, less than 3.3, less than 3.2, less than 3.1, less than 3, less than 2.9, less than 2.8, less than 2.7, less than 2.6, less than 2.5, less than 2.4, less than 2.3, less than 2.2, less than 2.1, less than 2, less than 1.9, less than 1.8, less than 1.7, or less than 1.6. In some embodiments, the molar ratio of structural unit (c) to the sum of structural units (a) and (b) in the copolymer is more than 1.5, more than 1.6, more than 1.7, more than 1.8, more than 1.9, more than 2, more than 2.1, more than 2.2, more than 2.3, more than 2.4, more than 2.5, more than 2.6, more than 2.7, more than 2.8, more than 2.9, more than 3, more than 3.1, more than 3.2, more than 3.3, more than 3.4, more than 3.5, more than 3.6, more than 3.7, more than 3.8, or more than 3.9.

[0161] In some embodiments, the molar ratio of structural unit (c) to the sum of structural units (a1), (a2) and (b) in the copolymer is from about 1.5 to about 4, from about 1.6 to about 4, from about 1.7 to about 4, from about 1.8 to about 4, from about 1.9 to about 4, from about 2 to about 4, from about 2 to about 3.9, from about 2 to about 3.8, from about 2 to about 3.7, from about 2 to about 3.6, from about 2 to about 3.5, from about 2 to about 3.4, from about 2 to about 3.3, from about 2 to about 3.2, from about 2 to about 3.1, from about 2 to about 3, from about 2.2 to about 3.5, or from about 2.4 to about 3.8.

[0162] In some embodiments, the molar ratio of structural unit (c) to the sum of structural units (a1), (a2) and (b) in the copolymer is less than 4, less than 3.9, less than 3.8, less than 3.7, less than 3.6, less than 3.5, less than 3.4, less than 3.3, less than 3.2, less than 3.1, less than 3, less than 2.9, less than 2.8, less than 2.7, less than 2.6, less than 2.5, less than 2.4, less than 2.3, less than 2.2, less than 2.1, less than 2, less than 1.9, less than 1.8, less than 1.7, or less than 1.6. In some embodiments, the molar ratio of structural unit (c) to the sum of structural units (a1), (a2) and (b) in the copolymer is more than 1.5, more than 1.6, more than 1.7, more than 1.8, more than 1.9, more than 2, more than 2.1, more than 2.2, more than 2.3, more than 2.4, more than 2.5, more than 2.6, more than 2.7, more than 2.8, more than 2.9, more than 3, more than 3.1, more than 3.2, more than 3.3, more than 3.4, more than 3.5, more than 3.6, more than 3.7, more than 3.8, or more than 3.9.

[0163] In some embodiments, the molar ratio of the sum of structural units (c) and (a) to structural unit (b) in the copolymer is from about 5 to about 15, from about 5 to about 14.75, from about 5 to about 14.5, from about 5 to about 14.25, from about 5 to about 14, from about 5 to about 13.75, from about 5 to about 13.5, from about 5 to about 13, from about 5 to about 12.75, from about 5 to about 12.5, from about 5 to about 12.25, from about 5 to about 12, from about 5 to about 11.75, from about 5 to about 11.5, from about 5 to about 11.25, from about 5 to about 11, from about 5 to about 10.75, from about 5 to about 10.5, from about 5 to about 10.25, from about 5 to about 10, from about 5.5 to about 15, from about 6 to about 15, from about 6.5 to 15, or from about 7 to about 15.

[0164] In some embodiments, the molar ratio of the total of structural units (c) and structural unit (a) to structural unit (b) in the copolymer is less than 15, less than 14.5, less than 14, less than 13.5, less than 13, less than 12.5, less than 12, less than 11.5, less than 11, less than 10.5, less than 10, less than 9.5, less than 9, less than 8.5, less than 8, less than 7.5, less than 7, less than 6.5, less than 6, or less than 5.5. In some embodiments, the molar ratio of the total of structural units (c) and structural unit (a) to structural unit (b) in the copolymer is more than 5, more than 5.5, more than 6, more than 6.5, more than 7, more than 7.5, more than 8, more than 8.5, more than 9, more than 9.5, more than 10, more than 10.5, more than 11, more than 11.5, more than 12, more than 12.5, more than 13, more than 13.5, more than 14, or more than 14.5.

[0165] In some embodiments, the molar ratio of the total of structural units (c), structural unit (a1) and structural unit (a2) to structural unit (b) in the copolymer is from about 5 to about 15, from about 5 to about 14.75, from about 5 to about 14.5, from about 5 to about 14.25, from about 5 to about 14, from about 5 to about 13.75, from about 5 to about 13.5, from about 5 to about 13, from about 5 to about 12.75, from about 5 to about 12.5, from about 5 to about 12.25, from about 5 to about 12, from about 5 to about 11.75, from about 5 to about 11.5, from about 5 to about 11.25, from about 5 to about 11, from about 5 to about 10.75, from about 5 to about 10.5, from about 5 to about 10.25, from about 5 to about 10, from about 5.5 to about 15, from about 6 to about 15, from about 6.5 to about 15, or from about 7 to about 15.

[0166] In some embodiments, the total molar ratio of structural unit (c), structural unit (a1), and structural unit (a2) to structural unit (b) in the copolymer is less than 15, less than 14.5, less than 14, less than 13.5, less than 13, less than 12.5, less than 12, less than 11.5, less than 11, less than 10.5, less than 10, less than 9.5, less than 9, less than 8.5, less than 8, less than 7.5, less than 7, less than 6.5, less than 6, or less than 5.5. In some embodiments, the total molar ratio of structural unit (c), structural unit (a1), and structural unit (a2) to structural unit (b) in the copolymer is more than 5, more than 5.5, more than 6, more than 6.5, more than 7, more than 7.5, more than 8, more than 8.5, more than 9, more than 9.5, more than 10, more than 10.5, more than 11, more than 11.5, more than 12, more than 12.5, more than 13, more than 13.5, more than 14, or more than 14.5.

[0167] The addition of ester group-containing monomers in the preparation of the binder compositions disclosed herein has been found to result in deterioration of electrochemical performance. In some embodiments, the binder composition does not have a structural unit derived from an ester group-containing monomer. In some embodiments, the ester group-containing monomer is C 1 ~C 20 alkyl acrylate, C 1 ~C 20It is an alkyl (meth)acrylate, a cycloalkyl acrylate, or a combination thereof. In 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.

[0168] 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, 2-chloro-1,3-butadiene, substituted linear conjugated pentadienes, and substituted side-chain conjugated hexadienes.

[0169] In some embodiments, the binder composition does not contain structural units derived from aromatic vinyl group-containing monomers. Examples of aromatic vinyl group-containing monomers include styrene, α-methylstyrene, vinyltoluene, and divinylbenzene.

[0170] 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.

[0171] 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.

[0172] 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 40,000 mPa·s, from 10,000 mPa·s to about 37,500 mPa·s, from 10,000 mPa·s to about 35,000 mPa·s, from 10,000 mPa·s to about 32,500 mPa·s, from 10,000 mPa·s to about 30,000 mPa·s, from 10,000 mPa·s to about 29,000 mPa·s, from about 10,000 mPa·s to about 28,000 mPa·s, from about 10,000 mPa·s to about 27,000 mPa·s, from about 10,000 mPa·s to about 26,000 mPa·s, from about 10,000 mPa·s to about 25,000 mPa·s, from about 10,000 mPa·s to about 24,000 mPa·s, from about 10,000 mPa·s to about 23,000 mPa·s, from about 10,000 mPa·s to about 22,000 mPa·s, from about 10,000 mPa·s to about 21,000 mPa·s, from about 10,000 mPa·s to about 20,000 mPa·s, from about 15,000 mPa·s to about 30,000 mPa·s, from about 15,000 mPa·s to about 25,000 mPa·s, or from about 15,000 mPa·s to about 35,000 mPa·s.

[0173] 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, greater than 47,500 mPa·s.

[0174] In some embodiments, the solids content of the binder composition is about 12% to about 18%, about 12.2% to about 18%, about 12.4% to about 18%, about 12.6% to about 18%, about 12.8% to about 18%, about 13% to about 18%, about 13% to about 17.8%, about 13% to about 17.6%, about 13% to about 17.4%, about 13% to about 17.2%, about 13% to about 17%, about 13.1 to about 17%, about 13.2 to about 17%, about 13.3 to about 17%, about 13.3 to about 17%, about 13.4% to about 17%, about 13.5% to about 17%, about 13.6% to about 17%, about 13.7% to about 17%, about 13.8% to about 17%, about 13.9% to about 17%, about 14% to about 16.9%, about 14% to about 16.8%, about 14% to about 16.7%, about 14% to about 16.6%, about 14% to about 16.5%, about 14% to about 16.4%, about 14% to about 16.3%, about 14% to about 16.2%, about 14% to about 16.1%, about 14% to about 16% by weight, based on the total weight of the binder composition.

[0175] In some embodiments, the solids content of the binder composition is less than 18%, less than 17.8%, less than 17.6%, less than 17.4%, less than 17.2%, less than 17%, less than 16.8%, less than 16.6%, less than 16.4%, less than 16.2%, less than 16%, less than 15.8%, less than 15.6%, less than 15.4%, less than 15.2%, less than 15%, less than 14.8%, less than 14.6%, less than 14.4%, less than 14.2%, less than 14%, less than 13.8%, less than 13.6%, less than 13.4%, less than 13.2%, less than 13%, less than 12.8%, less than 12.6%, less than 12.4% or less than 12.2% by weight, based on the total weight of the binder composition. In some embodiments, the solids content of the binder composition is more than 12%, more than 12.2%, more than 12.4%, more than 12.6%, more than 12.8%, more than 13%, more than 13.2%, more than 13.4%, more than 13.6%, more than 13.8%, more than 14%, more than 14.2%, more than 14.4%, more than 14.6%, more than 14.8%, more than 15%, more than 15.2%, more than 15.4%, more than 15.6%, more than 15.8%, more than 16%, more than 16.2%, more than 16.4%, more than 16.6%, more than 16.8%, more than 17%, more than 17.2%, more than 17.4%, more than 17.6% or more than 17.8% by weight, based on the total weight of the binder composition.

[0176] In some embodiments, the weight average molecular weight of the binder composition is from about 100,000 g / mol to about 200,000 g / mol, from about 105,000 g / mol to about 200,000 g / mol, from about 110,000 g / mol to about 200,000 g / mol, from about 115,000 g / mol to about 200,000 g / mol, from about 120,000 g / mol to about 200,000 g / mol, from about 125,000 g / mol to about 200,000 g / mol, from about 130,000 g / mol to about 200,000 g / mol, from about 130,000 g / mol to about 195,000 g / mol, from about 130,000 g / mol to about 190,000 g / mol, from about 130,000 g / mol to about 185,000 g / mol, from about 130,000 g / mol to about 180,000 g / mol, from about 130,000 g / mol to about 175,000 g / mol, from about 130,000 g / mol to about 170,000 g / mol, from about 135,000 g / mol to about 170,000 g / mol, from about 140,000 g / mol to about 170,000 g / mol, from about 145,000 g / mol to about 170,000 g / mol, from about 150,000 g / mol to about 170,000 g / mol, from about 150,000 g / mol to about 165,000 g / mol, or from about 155,000 g / mol to about 165,000 g / mol. When the weight average molecular weight of the binder composition is not more than the above upper limit value, the coatability of the binder composition is ensured, and the adhesive strength of the binder composition can be improved, so that a smooth binder composition layer can be obtained. On the other hand, when the weight average molecular weight of the binder composition is not less than the lower limit value defined above, the binding property of the binder composition is ensured, and the adhesive strength and the secondary battery cycle characteristics of the binder composition can be improved.

[0177] 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 155,000 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 or less than 105,000 g / mol. In some embodiments, the weight average molecular weight of the binder composition is more than 100,000 g / mol, more than 105,000 g / mol, more than 110,000 g / mol, more than 115,000 g / mol, more than 120,000 g / mol, more than 125,000 g / mol, more than 130,000 g / mol, more than 135,000 g / mol, more than 140,000 g / mol, more than 145,000 g / mol, more than 150,000 g / mol, more than 155,000 g / mol, more than 160,000 g / mol, more than 165,000 g / mol, more than 170,000 g / mol, more than 175,000 g / mol, more than 180,000 g / mol, more than 185,000 g / mol, more than 190,000 g / mol or more than 195,000 g / mol.

[0178] 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, from about 45,000 g / mol to about 100,000 g / mol, from about 50,000 g / mol to about 100,000 g / mol, from about 50,000 g / mol to about 95,000 g / mol, from about 50,000 g / mol to about 90,000 g / mol, from about 50,000 g / mol to about 85,000 g / mol, from about 50,000 g / mol to about 80,000 g / mol, from about 55,000 g / mol to about 80,000 g / mol, from about 60,000 g / mol to about 80,000 g / mol, from about 65,000 g / mol to about 75,000 g / mol, or from about 60,000 g / mol to about 90,000 g / mol.

[0179] 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 more than 10,000 g / mol, more than 15,000 g / mol, more than 20,000 g / mol, more than 25,000 g / mol, more than 30,000 g / mol, more than 35,000 g / mol, more than 40,000 g / mol, more than 45,000 g / mol, more than 50,000 g / mol, more than 55,000 g / mol, more than 60,000 g / mol, more than 65,000 g / mol, more than 70,000 g / mol, more than 75,000 g / mol, more than 80,000 g / mol, more than 85,000 g / mol, more than 90,000 g / mol or more than 95,000 g / mol.

[0180] 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.

[0181] 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.

[0182] In some embodiments, the average particle size of the binder composition is from about 10 μm to about 50 μm, from about 12 μm to about 50 μm, from about 14 μm to about 50 μm, from about 16 μm to about 50 μm, from about 18 μm to about 50 μm, from about 20 μm to about 50 μm, from about 20 μm to about 48 μm, from about 20 μm to about 46 μm, from about 20 μm to about 44 μm, from about 20 μm to about 42 μm, from about 20 μm to about 40 μm, from about 22 μm to about 40 μm, from about 22 μm to about 38 μm, from about 24 μm to about 38 μm, from about 24 μm to about 36 μm, from about 26 μm to about 34 μm, from about 28 μm to about 34 μm, or from about 28 μm to about 32 μm.

[0183] In some embodiments, the average particle size of the binder composition is less than 50 μm, less than 48 μm, less than 46 μm, less than 44 μm, less than 42 μm, less than 40 μm, less than 38 μm, less than 36 μm, less than 34 μm, less than 32 μm, 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 or less than 12 μm. In some embodiments, the average particle size of the binder composition is greater than 10 μm, greater than 12 μm, greater than 14 μm, greater than 16 μm, greater than 18 μm, greater than 20 μm, greater than 22 μm, greater than 24 μm, greater than 26 μm, greater than 28 μm, greater than 30 μm, greater than 32 μm, greater than 34 μm, greater than 36 μm, greater than 38 μm, greater than 40 μm, greater than 42 μm, greater than 44 μm, greater than 46 μm or greater than 48 μm.

[0184] In some embodiments, the D50 of the binder composition is from about 1 μm to about 100 μm, from about 1 μm to about 98 μm, from about 1 μm to about 96 μm, from about 1 μm to about 94 μm, from about 1 μm to about 92 μm, from 1 μm to 90 μm, from about 1 μm to about 88 μm, from about 1 μm to about 86 μm, from about 1 μm to 84 μm, from about 1 μm to about 82 μm, from about 1 μm to about 80 μm, from about 1 μm to about 75 μm, from about 1 μm to about 70 μm, from about 1 μm to about 65 μm, from about 1 μm to about 60 μm, from about 1 μm to about 55 μm, from about 1 μm to about 50 μm, from about 1 μm to about 45 μm, from about 1 μm to about 40 μm, from about 1 μm to about 35 μm, from about 1 μm to about 30 μm, from about 1 μm to about 25 μm, from about 2 μm to about 25 μm, from about 3 μm to about 25 μm, from about 4 μm to about 25 μm or from about 5 μm to about 25 μm.

[0185] In some embodiments, the D50 of the binder composition is less than 100 μm, less than 95 μm, less than 90 μm, less than 85 μm, less than 80 μm, less than 75 μm, less than 70 μm, less than 65 μm, less than 60 μm, less than 55 μm, less than 50 μm, less than 45 μm, less than 40 μm, less than 35 μm, less than 30 μm, less than 25 μm, less than 20 μm, less than 15 μm, less than 10 μm or less than 5 μm. In some embodiments, the D50 of the binder composition is greater than 1 μm, greater than 5 μm, greater than 10 μm, greater than 15 μm, greater than 20 μm, greater than 25 μm, greater than 30 μm, greater than 35 μm, greater than 40 μm, greater than 45 μm, greater than 50 μm, greater than 55 μm, greater than 60 μm, greater than 65 μm, greater than 70 μm, greater than 75 μm, greater than 80 μm, greater than 85 μm, greater than 90 μm or greater than 95 μm.

[0186] In some embodiments, the D10 of the binder composition is from about 0.1 μm to about 20 μm, from about 0.1 μm to about 19.5 μm, from about 0.1 μm to about 19 μm, from about 0.1 μm to about 18.5 μm, from about 0.1 μm to about 18 μm, from about 0.1 μm to about 17.5 μm, from about 0.1 μm to about 17 μm, from about 0.1 μm to about 16.5 μm, from about 0.1 μm to about 16 μm, from about 0.1 μm to about 15.5 μm, from about 0.1 μm to about 15 μm, from about 0.1 μm to about 14.5 μm, from about 0.1 μm to about 14 μm, from about 0.1 μm to about 13.5 μm, from about 0.1 μm to about 13 μm, from about 0.1 μm to about 12.5 μm, from about 0.1 μm to about 12 μm, from about 0.1 μm to about 11.5 μm, from about 0.1 μm to about 11 μm, from about 0.1 μm to about 10.5 μm or from about 0.1 μm to about 10 μm.

[0187] In some embodiments, the D10 of the binder composition is less than 20 μm, less than 19 μm, less than 18 μm, less than 17 μm, less than 16 μm, less than 15 μm, less than 14 μm, less than 13 μm, less than 12 μm, less than 11 μm, less than 10 μm, less than 9 μm, less than 8 μm, less than 7 μm, less than 6 μm, less than 5 μm, less than 4 μm, less than 3 μm, less than 2 μm, less than 1 μm or less than 0.5 μm. In some embodiments, the D10 of the binder composition is greater than 0.1 μm, greater than 0.5 μm, greater than 1 μm, greater than 2 μm, greater than 3 μm, greater than 4 μm, greater than 5 μm, greater than 6 μm, greater than 7 μm, greater than 8 μm, greater than 9 μm, greater than 10 μm, greater than 11 μm, greater than 12 μm, greater than 13 μm, greater than 14 μm, greater than 15 μm, greater than 16 μm, greater than 17 μm, greater than 18 μm or greater than 19 μm.

[0188] In some embodiments, the D90 of the binder composition is from about 10 μm to about 300 μm, from about 15 μm to about 300 μm, from about 20 μm to about 300 μm, from about 25 μm to about 300 μm, from about 30 μm to about 300 μm, from about 35 μm to about 300 μm, from about 40 μm to about 300 μm, from about 45 μm to about 300 μm, from about 50 μm to about 300 μm, from about 60 μm to about 300 μm, from about 70 μm to about 300 μm, from about 80 μm to about 300 μm, from about 90 μm to about 300 μm, from about 100 μm to about 300 μm, from about 120 μm to about 300 μm, from about 140 μm to about 300 μm, from about 160 μm to about 300 μm, from about 180 μm to about 300 μm, from about 200 μm to about 300 μm, from about 220 μm to about 300 μm or from about 240 μm to about 300 μm.

[0189] In some embodiments, the D90 of the binder composition is less than 300 μm, less than 295 μm, less than 290 μm, less than 285 μm, less than 280 μm, less than 275 μm, less than 270 μm, less than 265 μm, less than 260 μm, less than 255 μm, less than 250 μm, less than 225 μm, less than 200 μm, less than 175 μm, less than 150 μm, less than 125 μm, less than 100 μm, less than 75 μm, less than 50 μm, less than 25 μm or less than 15 μm. In some embodiments, the D90 of the binder composition is greater than 10 μm, greater than 15 μm, greater than 20 μm, greater than 25 μm, greater than 30 μm, greater than 35 μm, greater than 40 μm, greater than 45 μm, greater than 50 μm, greater than 75 μm, greater than 100 μm, greater than 125 μm, greater than 150 μm, greater than 175 μm, greater than 200 μm, greater than 225 μm, greater than 250 μm or greater than 275 μm.

[0190] The binder composition of the present invention exhibits a strong adhesive force to the current collector. The fact that the binder composition has good adhesive strength to the current collector is important for promoting the bonding force of the electrode layer to the current collector, preventing separation, and improving the mechanical stability of the electrode in the production of battery electrodes. 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, about 2 N / cm to about 3.9 N / cm, about 2 N / cm to about 3.8 N / cm, about 2 N / cm to about 3.7 N / cm, about 2 N / cm to about 3.6 N / cm, about 2 N / cm to about 3.5 N / cm, about 2 N / cm to about 3.4 N / cm, about 2 N / cm to about 3.3 N / cm, about 2 N / cm to about 3.2 N / cm, about 2 N / cm to about 3.1 N / cm, about 2 N / cm to about 3 N / cm, about 2.5 N / cm to about 3.5 N / cm, about 2.3 N / cm to about 3.7 N / cm, about 2.5 N / cm to about 3 N / cm or about 3 N / cm to about 3.5 N / cm.

[0191] In some embodiments, the adhesion 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 adhesion 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.

[0192] 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.

[0193] In some embodiments, the electrode active material is a cathode active material, and the cathode active material is LiCoO 2 、LiNiO 2 、LiNi x Mn y O 2 、Li 1+z Ni x Mn y Co 1-x-y O 2 、LiNi x Co y Al z O 2 、LiV 2 O 5 、LiTiS 2 、LiMoS2 , LiMnO 2 , LiCrO 2 , LiMn 2 O 4 , Li 2 MnO 3 , LiFeO 2 , LiFePO 4 and selected from the group consisting of combinations thereof, each x is independently from 0.2 to 0.9, each y is independently from 0.1 to 0.45, and each z is independently from 0 to 0.2. In certain embodiments, the cathode active material is LiCoO 2 , LiNiO 2 , LiNi x Mn y O 2 , Li 1+z Ni x Mn y Co 1-x-y O 2 (NMC), LiNi x Co y Al z O2, LiV 2 O 5 , LiTiS 2 , LiMoS 2 , LiMnO 2 , LiCrO 2 , LiMn 2 O 4 , LiFeO 2 , LiFePO 4 and combinations thereof, each x is independently from 0.4 to 0.6, each y is independently from 0.2 to 0.4, and each z is independently from 0 to 0.1. In other embodiments, the cathode active material is not LiCoO 2 , LiNiO 2 , LiV 2 O 5 , LiTiS 2 , LiMoS 2 , LiMnO 2 , LiCrO 2 , LiMn 2 O 4 , LiFeO 2 , or LiFePO 4 . In a further embodiment, the cathode active material is LiNi x Mny O 2 , Li 1+z Ni x Mn y Co 1-x-y O 2 、 or LiNi x Co y Al z O 2 Instead, each x is independently from 0.2 to 0.9, each y is independently from 0.1 to 0.45, and each z is independently from 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) O 2 , 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 has the general formula Li 1+x Ni a Mn b Co c Al (1-a-b-c) O 2 and 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.

[0194] 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.

[0195] In some embodiments, the cathode active material is LiNi 0.33 Mn 0.33 Co 0.33 O 2 (NMC333), LiNi 0.4 Mn 0.4 Co 0.2 O 2 , LiNi 0.5 Mn 0.3 Co 0.2 O 2 (NMC532), LiNi 0.6 Mn 0.2 Co 0.2 O 2 (NMC622), LiNi 0.7 Mn 0.15 Co 0.15 O 2 , LiNi 0.8 Mn 0.1 Co 0.1 O 2 (NMC811), LiNi 0.92 Mn 0.04 Co 0.04 O 2 , LiNi 0.8 Co 0.15 Al 0.05 O 2 (NCA), LiNiO 2 (LNO) and combinations thereof.

[0196] In other embodiments, the cathode active material is not LiCoO 2 , LiNiO 2 , LiMnO 2 , LiMn 2 O 4 , or Li 2 MnO 3 . In further embodiments, the cathode active material is LiNi 0.33 Mn 0.33 Co 0.33 O 2 , LiNi 0.4 Mn 0.4 Co 0.2 O 2 , LiNi 0.5 Mn 0.3 Co 0.2 O 2 , LiNi 0.6Mn 0.2 Co 0.2 O 2 、LiNi 0.7 Mn 0.15 Co 0.15 O 2 、LiNi 0.8 Mn 0.1 Co 0.1 O 2 、LiNi 0.92 Mn 0.04 Co 0.04 O 2 Or LiNi 0.8 Co 0.15 Al 0.05 O 2 is not.

[0197] In certain embodiments, the cathode active material comprises, or is, a core - shell composite having a core and a shell structure. Here, the core and the shell are each independently Li 1+x Ni a Mn b Co c Al (1-a-b-c) O 2 、LiCoO 2 、LiNiO 2 、LiMnO 2 、LiMn 2 O 4 、Li 2 MnO 3 、LiCrO 2 、Li 4 Ti 5 O 12 、LiV 2 O 5 、LiTiS 2 、LiMoS 2、and includes a lithium transition metal oxide selected from the group consisting of these 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 the shell each independently include two or more lithium transition metal oxides. In some embodiments, one of the core or the shell includes only one lithium transition metal oxide, and the other includes two or more lithium transition metal oxides. The lithium transition metal oxides or oxides of the core and the shell may be the same, or they may be different or partially different. In some embodiments, two or more lithium transition metal oxides are uniformly distributed on the core. In certain embodiments, 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.

[0198] In some embodiments, each of the lithium transition metal oxides of the core and the shell 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 the shell each independently include two or more doped lithium transition metal oxides. In one embodiment, two or more doped lithium transition metal oxides are uniformly distributed on the core and / or the shell. In certain embodiments, two or more doped lithium transition metal oxides are not uniformly distributed on the core and / or the shell.

[0199] In some embodiments, the cathode active material includes a core-shell composite including a core including a lithium transition metal oxide and a shell including a transition metal oxide, or is a core-shell composite. In certain embodiments, the lithium transition metal oxide is Li 1+x Ni a Mn b Co c Al (1-a-b-c) O 2 , LiCoO 2 , LiNiO 2, LiMnO 2 , LiMn 2 O 4 , Li 2 MnO 3 , LiCrO 2 , Li 4 Ti 5 O 12 , LiV 2 O 5 , LiTiS 2 , LiMoS 2 , and selected from the group consisting of combinations thereof, where -0.2 ≦ x ≦ 0.2, 0 ≦ a < 1, 0 ≦ b < 1, 0 ≦ c < 1, and a + b + c ≦ 1. In certain embodiments, the transition metal oxide is Fe 2 O 3 , MnO 2 , Al 2 O 3 , MgO, ZnO, TiO 2 , La 2 O 3 , CeO 2 , SnO 2 , ZrO 2 , RuO 2 , and selected from the group consisting of combinations thereof. In certain embodiments, the shell comprises a lithium transition metal oxide and a transition metal oxide.

[0200] In some embodiments, the diameter of the core is from about 1 μm to about 15 μm, from about 3 μm to about 15 μm, from about 3 μm to about 10 μm, from about 5 μm to about 10 μm, from about 5 μm to about 45 μm, from about 5 μm to about 35 μm, from about 5 μm to about 25 μm, from about 10 μm to about 45 μm, from about 10 μm to about 40 μm, or from about 10 μm to about 35 μm, from about 10 μm to about 25 μm, from about 15 μm to about 45 μm, from about 15 μm to about 30 μm, from about 15 μm to about 25 μm, from about 20 μm to about 35 μm, or from about 20 μm to about 30 μm. In certain embodiments, the thickness of the shell is from about 1 μm to about 45 μm, from about 1 μm to about 35 μm, from about 1 μm to about 25 μm, from about 1 μm to about 15 μm, from about 1 μm to about 10 μm, from about 1 μm to about 5 μm, from about 3 μm to about 15 μm, from about 3 μm to about 10 μm, from about 5 μm to about 10 μm, from about 10 μm to about 35 μm, from about 10 μm to about 20 μm, from about 15 μm to about 30 μm, from about 15 μm to about 25 μm, or from about 20 μm to about 35 μm. In certain embodiments, the ratio of the diameter or thickness of the core to the shell is from 15:85 to 85:15, from 25:75 to 75:25, from 30:70 to 70:30, or from 40:60 to 60:40. In certain embodiments, the ratio of the volume or weight of the core to the shell is 95:5, 90:10, 80:20, 70:30, 60:40, 50:50, 40:60, or 30:70.

[0201] The current collector functions to collect the electrons generated by the electrochemical reaction of the cathode active material or supply the electrons necessary for the electrochemical reaction. In certain embodiments, the current collector can be in the form of a foil, sheet, or film. In specific embodiments, the current collector is stainless steel, titanium, nickel, aluminum, copper, or an alloy thereof, or an electrically conductive resin. In specific embodiments, the current collector has a two-layer structure including an outer layer and an inner layer, the outer layer contains a conductive material, and the inner layer contains an insulating material or another conductive material, for example, a polymer insulating material coated with aluminum or an aluminum film attached with a conductive resin layer. In certain embodiments, the current collector has a three-layer structure including an outer layer, an intermediate layer, and an inner layer, the outer layer and the inner layer contain conductive materials, and the intermediate layer contains an insulating material or another conductive material, for example, a plastic substrate coated with metal films on both sides. In specific embodiments, each of the outer layer, the intermediate layer, and the inner layer is independently stainless steel, titanium, nickel, aluminum, copper, or an alloy thereof, or an electrically conductive resin. In some embodiments, the insulating material is a polymer material selected from the group consisting of polycarbonate, polyacrylate, polyacrylonitrile, polyester, polyamide, polystyrene, polyurethane, epoxy, poly(acrylonitrile butadiene styrene), polyimide, polyolefin, polyethylene, polypropylene, polyphenylene sulfide, poly(vinyl ester), polyvinyl chloride, polyether, polyphenylene oxide, cellulose polymer, and combinations thereof. In specific embodiments, the current collector has three or more layers. In certain embodiments, the current collector is coated with a protective coating. In specific embodiments, the protective coating contains a carbon-containing material. In some embodiments, the current collector is not coated with a protective coating.

[0202] The thickness of the current collector affects the volume it occupies within the battery, the amount of electrode active material required, and the capacity within the battery. In some embodiments, the current collector has a thickness of from about 5 μm to about 30 μm. In certain embodiments, the current collector has a thickness of from about 5 μm to about 20 μm, from about 5 μm to about 15 μm, from about 10 μm to about 30 μm, from about 10 μm to about 25 μm, or from about 10 μm to about 20 μm.

[0203] 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 greater than 5 μm, greater than 7 μm, greater than 10 μm, greater than 12 μm, greater than 14 μm, greater than 16 μm, greater than 18 μm, greater than 20 μm, greater than 22 μm, greater than 24 μm, greater than 26 μm or greater than 28 μm.

[0204] The conductive agent is for improving 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 nanoplatelet, carbon fiber, carbon nanofiber, graphitized carbon flake, carbon tube, activated carbon, Super P, 0-dimensional KS6, 1-dimensional vapor grown carbon fiber (VGCF), mesoporous carbon and combinations thereof.

[0205] Also, the cathode produced using the binder composition in the present invention exhibits strong adhesion between the electrode layer and the current collector. The electrode layer having good peel strength with respect to the current collector is important for preventing peeling or separation of the electrode, which greatly affects the mechanical stability of the electrode and the cycle performance of the battery. Therefore, it is necessary for the electrode to have sufficient peel strength to withstand the harshness of battery manufacturing.

[0206] In some embodiments, 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, 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, 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.

[0207] 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, 6.0 N / cm or more, 6.5 N / cm or more, 7.0 N / cm or more, or 7.5 N / cm or more. In some embodiments, the peel strength between the current collector and the electrode layer is less than 8.0 N / cm, less than 7.5 N / cm, less than 7.0 N / cm, 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.

[0208] The degree of swelling of the binder composition due to electrolyte uptake in a secondary battery provides insights into the crystallinity of the binder composition and how the binder composition interacts with the electrolyte. On the one hand, a binder composition with high crystallinity exhibits low swelling behavior that can act as a barrier to solvent penetration, resulting in a shorter ion transport path and a lower internal resistance. More importantly, it can change the mechanical properties of the swollen polymer, which is essential for stable battery performance. On the other hand, a binder composition with low crystallinity has more amorphous regions where a larger amount of electrolyte can penetrate the binder composition to ensure good ion transport. The semi-crystalline binder composition disclosed herein benefits from both influencing factors and thus exhibits excellent electrochemical performance.

[0209] In some embodiments, the electrolyte swelling of the binder composition is from about 2% to about 4%, about 2.1% to about 4%, about 2.2% to about 4%, about 2.3% to about 4%, about 2.4% to about 4%, about 2.5% to about 4%, about 2.6% to about 4%, about 2.7% to about 4%, 2.8% to about 4%, 2.9% to about 4%, 3% to about 4%, 3.1% to about 4%, 3.2% to about 4%, 3.3% to about 4%, 3.4% to about 4%, 3.5% to about 4%, from about 3% to about 3.9%, from about 3% to about 3.8%, from about 3% to about 3.7%, from about 3% to about 3.6%, from about 3% to about 3.5%, from about 2.5% to about 3.5%, from about 2.5% to about 3.4%, from about 2.5% to about 3.3%, from about 2.5% to about 3.2%, from about 2.5% to about 3.1%, from about 2.5% to about 3%, from about 2% to about 3%, from about 2% to about 2.9%, from about 2% to about 2.8%, from about 2% to about 2.7%, from about 2% to about 2.6%, from about 2% to about 2.5%, from about 2.2% to about 3.7% or from about 2.7% to about 3.3%.

[0210] In some embodiments, the electrolyte swelling of the binder composition is less than 4%, less than 3.9%, less than 3.8%, less than 3.7%, less than 3.6%, less than 3.5%, less than 3.4%, less than 3.3%, less than 3.2%, less than 3.1%, less than 3%, less than 2.9%, less than 2.8%, less than 2.7%, less than 2.6%, less than 2.5%, less than 2.4%, less than 2.3%, less than 2.2% or less than 2.1%. In some embodiments, the electrolyte swelling of the binder composition is greater than 2%, greater than 2.1%, greater than 2.2%, greater than 2.3%, greater than 2.4%, greater than 2.5%, greater than 2.6%, greater than 2.7%, greater than 2.8%, greater than 2.9%, greater than 3%, greater than 3.1%, greater than 3.2%, greater than 3.3%, greater than 3.4%, greater than 3.5%, greater than 3.6%, greater than 3.7%, greater than 3.8% or greater than 3.9%.

[0211] Since the method disclosed herein can use an aqueous solvent in the manufacturing process, it can save processing time and equipment, and has the advantage of improved safety because there is no need to handle or recycle dangerous organic solvents. In addition, since the entire process is simplified, costs are reduced. Therefore, since this method is low-cost and easy to handle, it is particularly suitable for industrial processes.

[0212] The following examples are presented to illustrate embodiments of the present invention and are not intended to limit the invention to the specific embodiments defined. 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 recited ranges may still fall within the scope of the present invention. The specific details described in each example should not be construed as essential features of the present invention. Examples

[0213] The pH value of the binder composition was measured using an electrode pH meter (ION2700, manufactured by UTEC Instruments).

[0214] The viscosity of the binder composition was measured at 25 °C using a rotational viscometer (NDJ-5S, Shanghai JT Electronic Technology Co., Ltd., China).

[0215] The adhesion strength of the dried binder composition layer was measured with a tensile testing machine (DZ-106A, Dongguan Zonhao 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 is 2 μm. The binder composition was applied onto the current collector and dried to obtain a binder composition layer with a thickness of 10 μm to 12 μm. Next, the coated current collector was placed in a constant temperature environment at 25 °C and 50% - 60% humidity for 30 minutes. A strip-shaped adhesive tape (3M; USA, model number 810) with a width of 18 mm and a length of 20 mm was attached to the surface of the binder composition layer. The binder composition strip was clamped in the testing machine, the tape was folded back 180 degrees onto itself, inserted into the movable jaw, and pulled at a peeling rate of 300 mm per minute at room temperature. The measured maximum peeling force was taken as the adhesion strength. The measurement was repeated 3 times and the average value was obtained.

[0216] The electrolyte swelling of the binder composition measures the degree of mass change of the binder composition before and after immersion in the electrolyte. Test pieces of dried binder composition strips with a length of 50 mm to 60 mm and a width of 1 mm were prepared. These dried binder composition strips were further dried at 80 °C for 1 to 2 hours to completely remove the moisture inside the strips. The weight of the dried binder composition strips was measured, and after cooling, they were placed in a sealed container together with the electrolyte. The binder composition strips were immersed in the electrolyte at 25 °C for 3 days. After taking out the binder composition strips from the container with the electrolyte, the electrolyte on the strip surface was absorbed with blotting paper. The weight of the immersed binder composition strips was measured. The ratio of the weight change of the strips before and after electrolyte immersion to the weight of the strips before electrolyte immersion was taken as the electrolyte swelling. The measurement was repeated 3 times and the average value was obtained.

[0217] The solid content of the binder composition is measured by the degree of mass change of the binder composition before and after drying. Weigh approximately 1 g of the binder composition into a weighing bottle and dry it in a vacuum dryer at 110 ± 5 °C and -0.09 MPa for more than 5 hours. After cooling this binder composition in a desiccator for about 15 minutes, its mass was measured. The mass difference of the binder composition before and after drying was determined, and the solid content (%) of the binder composition was calculated by the following formula.

[0218]

Number

[0219] 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. After the dissolution of the binder composition was completed, the solution was gently filtered through a 0.45 μm filter to prepare a measurement sample. Using standard polystyrene, a calibration curve was created such that the weight-average molecular weight and number-average molecular weight were calculated as standard substance conversion values. The molecular weight distribution in the binder composition is represented 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.

[0220] Column: Agilent PLgel 5um MIXED-C column

[0221] Eluent: Dimethylformamide

[0222] Flow rate: 1 ml / min

[0223] Sample weight: 2 mg

[0224] Detector: Waters2414 refractive index (RI) detector

[0225] Detection temperature: 35 °C

[0226] Standard substance: Polystyrene Example 1 A) Preparation of Binder Composition

[0227] 5.13 g of lithium hydroxide was dissolved in 3.85 g of pure water. Then, 8.98 g of the lithium hydroxide solution was added to a 500 mL round-bottom flask containing 289.17 g of distilled water. This mixture was stirred at 200 rpm for 30 minutes to obtain a first suspension.

[0228] Furthermore, 19.15 g of acrylic acid (AA) was added to the first suspension. This mixture was further stirred at 200 rpm for 30 minutes to obtain a second suspension.

[0229] 15.98 g of acrylamide (AM) was dissolved in 51.67 g of pure water. Then, 67.65 g of the AM solution was added to the second suspension. This mixture was further stirred at 200 rpm for 30 minutes to obtain a third suspension.

[0230] Next, 77.53 g of acrylonitrile (AN) was added to the third suspension. It was stirred at 200 rpm for 40 minutes to obtain a fourth suspension.

[0231] The fourth suspension was heated to 60 °C and stirred at 60 rpm for 45 minutes. 0.23 g of a water-soluble free radical initiator (ammonium persulfate, APS; Aladin Industrial Co., China) was dissolved in 82.68 g of pure water, and 0.04 g of a reducing agent (sodium bisulfite; Tianjin Dama Chemical Reagent Factory, China) was dissolved in 17.22 g of pure water. 17.26 g of the sodium bisulfite solution was added to the fourth suspension and stirred for 10 minutes. 82.91 g of the APS solution was added dropwise over 3 hours to form a fifth suspension. The fifth suspension was further stirred at 200 rpm at 65 °C for 20 hours.

[0232] After the reaction was completed, the temperature of the fifth suspension was lowered to 40 °C, and 0.69 g of lithium hydroxide (dissolved in 116.64 g of pure water) was added to the fifth suspension to adjust the pH to 7.42, forming the sixth suspension. The temperature of the sixth suspension was lowered to 30 °C, and a binder composition was prepared by filtration using a 200-mesh filter paper. The solid content of the binder composition was 14.85 wt.%. The weight-average molecular weight of the binder composition was 163,282 g / mol, the number-average molecular weight was 71,877 g / mol, and the polydispersity index was 2.27. The components and their respective blending ratios of the binder composition of Example 1 are shown in Table 1 below. Also, the pH, solid content, viscosity, adhesion strength, and electrolyte swelling of the binder composition of Example 1 were measured and shown in Table 2 below. B) Preparation of Cathode

[0233] While stirring with an overhead stirrer (R20, manufactured by IKA), 0.9 g of a conductive agent (SuperP; obtained from Timcal Ltd, Bodio, Switzerland) and 6 g of a binder composition (solid content 14.85 wt.%) were dispersed in deionized water to prepare a first mixture. After the addition, the first mixture was further stirred at 25 °C and a rotation speed of 1200 rpm for about 30 minutes.

[0234] Thereafter, while stirring with an overhead stirrer, 28.2 g of NMC622 (Shandong Tianqiao New Energy Co., Ltd., China) was added to the first mixture at 25 °C to prepare a second mixture. Next, the second mixture was degassed under a pressure of about 10 kPa for 1 hour. Thereafter, the second mixture was further stirred at 25 °C for about 60 minutes at a rotation speed of 1200 rpm to form a homogenized slurry.

[0235] This homogenized slurry was applied to one side of a 14-μm-thick aluminum foil as a current collector using a doctor blade coater. The slurry film coated on the aluminum foil was dried at about 85 °C for 120 minutes using a hot air dryer (DHG 10H, Huyue Equipment Co., Ltd., China) to form a cathode electrode layer. Next, the electrode was pressed to reduce the thickness of the cathode electrode layer to 27 μm, and the areal density was 5.2 mg / cm 2 was. C) Preparation of Anode

[0236] 90 wt.% of hard carbon (BTR New Energy Materials Inc, Shenzhen City, Guangdong Province, China), 1.5 wt.% of carboxymethyl cellulose (CMC, BSH-12, DKS Co., Ltd., Japan), 3.5 wt.% of SBR as a binder (AL-2001, Japan A&L Co., Ltd., Japan), and 5 wt.% of carbon black as a conductive agent were mixed in deionized water to prepare a slurry for the negative electrode. The solid content of the anode slurry was 50 wt.%. This slurry was applied to one side of a copper foil with a thickness of 8 μm using a doctor blade coater. The coating film on this copper foil was dried at about 85 °C for 120 minutes using a hot air dryer to obtain a negative electrode. Then, the electrode was pressed to reduce the thickness of the coating film to 18 μm. D) Assembly of Coin Cell

[0237] A CR2032 coin-type Li battery was assembled in an argon-filled glove box. The coated cathode plate and anode plate were cut into disk-shaped positive and negative electrodes, and the cathode and anode electrode plates were stacked alternately to form an electrode assembly, which was housed in a CR2032-type stainless steel case. The cathode electrode plate and the anode electrode plate were separated by a separator. The separator was a microporous membrane (MPM, Japan) made of non-woven fabric coated with ceramic, and its thickness was about 25 μm. Next, the electrode assembly was dried in a box-type resistance oven (DZF-6020, Shenzhen Kejing Star Technology Co., Ltd., China) at 105 °C for about 16 hours under vacuum.

[0238] Next, under a high-purity argon atmosphere with a moisture content and an oxygen content of 3 ppm or less respectively, an electrolyte was injected into the case holding the filled electrode. The electrolyte was a solution in which LiPF 6 (1 M) was mixed with ethylene carbonate (EC), ethyl methyl carbonate (EMC), and dimethyl carbonate (DMC) at a volume ratio of 1:1:1. After filling the electrolyte, the coin battery was vacuum-sealed and mechanically pressed using a standard circular punch die. E) Electrochemical Measurement

[0239] A coin cell was analyzed in a constant current mode using a multi-channel battery tester (BTS-4008-5V10mA, Neware Electronics Co., Ltd., obtained from China). After one cycle at C / 20, charge and discharge were performed at a rate of C / 2. A charge-discharge cycle test of the cell was carried out under the conditions of 3.0 to 4.3 V, a current density of C / 2, and 25 °C, and the discharge capacity was determined. The electrochemical performance of the coin cell of Example 1 was measured and shown in Table 2 below.

[0240] Example 2 : The binder composition was prepared in the same manner as in Example 1, except that 11.27 g of AA was added in the preparation of the second suspension, 20.27 g of AM was added in the preparation of the third suspension, and 81.12 g of AN was added in the preparation of the fourth suspension.

[0241] Example 3 : The binder composition was prepared in the same manner as in Example 1, except that 31.54 g of AA was added in the preparation of the second suspension, 13.52 g of AM was added in the preparation of the third suspension, 67.60 g of AN was added in the preparation of the fourth suspension, and 5.62 g of lithium hydroxide (dissolved in 116.64 g of pure water) was added in the preparation of the sixth suspension.

[0242] Example 4 : The binder composition was prepared in the same manner as in Example 1, except that 14.74 g of AA and 4.41 g of methacrylic acid (MAA) were added in the preparation of the second suspension. The weight average molecular weight of the binder composition was 159,836 g / mol, the number average molecular weight was 70,980 g / mol, and the polydispersity index was 2.25. Preparation of Binder Composition of Example 5

[0243] 4.99 g of lithium hydroxide was dissolved in 3.75 g of pure water. Then, 8.74 g of the lithium hydroxide solution was added to a 500 mL round-bottom flask containing 281.29 g of distilled water. This mixture was stirred at 200 rpm for 30 minutes to obtain the first suspension.

[0244] Furthermore, 15.62 g of AA and 4.67 g of MAA were added to the first suspension. This mixture was further stirred at 200 rpm for 30 minutes to obtain a second suspension.

[0245] 15.55 g of AM was dissolved in 50.27 g of pure water. Then, 65.82 g of the AM solution was added to the second suspension. This mixture was further stirred at 200 rpm for 30 minutes to obtain a third suspension.

[0246] Next, 73.77 g of AN was added to the third suspension. This mixture was stirred at 200 rpm for 40 minutes to obtain a fourth suspension.

[0247] The fourth suspension was heated to 60 °C and stirred at 60 rpm for 45 minutes. 0.29 g of a water-soluble free radical initiator (ammonium persulfate, APS; obtained from Aladdin Industries, China) was dissolved in 80.43 g of pure water, and 0.05 g of a reducing agent (sodium sulfite; obtained from Tianjin Dama Chemical Reagent Factory, China) was dissolved in 16.76 g of pure water. 16.81 g of the sodium bisulfite solution was added to the fourth suspension and stirred for 10 minutes. 80.72 g of the APS solution was added dropwise to the mixture over 3 hours to form a fifth suspension. The fifth suspension was further stirred at 200 rpm at 65 °C for 20 hours.

[0248] After the reaction was completed, the temperature of the fifth suspension was lowered to 40 °C, and 1.15 g of lithium hydroxide (dissolved in 101.39 g of pure water) was added to the fifth suspension to adjust the pH to 7.90, forming a sixth suspension. The temperature of the sixth suspension was lowered to 30 °C, and a binder composition was prepared by filtration using a 200-mesh filter paper. The solid content of the binder composition was 16.54 wt.%. Preparation of Binder Composition of Example 6

[0249] 6.37 g of lithium hydroxide was dissolved in 4.79 g of pure water. Then, 11.16 g of the lithium hydroxide solution was added to a 500 mL round-bottom flask containing 271.80 g of distilled water. This mixture was stirred at 200 rpm for 30 minutes to obtain a first suspension.

[0250] Furthermore, 20.45 g of AA and 6.10 g of MAA were added to the first suspension. This mixture was further stirred at 200 rpm for 30 minutes to obtain the second suspension.

[0251] 10.93 g of AM was dissolved in 48.57 g of pure water. Then, 59.50 g of the AM solution was added to the second suspension. This mixture was further stirred at 200 rpm for 30 minutes to obtain the third suspension.

[0252] Next, 68.41 g of AN was added to the third suspension. This mixture was stirred at 200 rpm for 40 minutes to obtain the fourth suspension.

[0253] The fourth suspension was heated to 60 °C and stirred at 60 rpm for 45 minutes. 0.28 g of a water-soluble free radical initiator (ammonium persulfate, APS; obtained from Aladdin Industries Corporation, China) was dissolved in 77.71 g of pure water, and 0.05 g of a reducing agent (sodium bisulfite; obtained from Tianjin Damao Chemical Reagent Factory, China) was dissolved in 16.19 g of pure water. 16.24 g of the sodium bisulfite solution was added to the fourth suspension and stirred for 10 minutes. 77.99 g of the APS solution was added dropwise over 3 hours to form the fifth suspension. The fifth suspension was further stirred at 200 rpm at 65 °C for 20 hours.

[0254] After the reaction was completed, the temperature of the fifth suspension was lowered to 40 °C, and 1.57 g of lithium hydroxide (dissolved in 74.14 g of pure water) was added to the fifth suspension to adjust the pH to 7.80, forming the sixth suspension. The sixth suspension was lowered to 30 °C, and a binder composition was prepared by filtration using a 200-mesh filter paper. The solid content of the binder composition was 17.47 wt.%.

[0255] Example 7 : The binder composition was prepared in the same manner as in Example 6, except that 15.80 g of AM was added in the preparation of the third suspension, 63.53 g of AN was added in the preparation of the fourth suspension, and 0.46 g of lithium hydroxide (dissolved in 198 g of pure water) was added in the preparation of the sixth suspension.

[0256] Example 8: The binder composition was prepared in the same manner as in Example 6, except that 14.21 g of AM was added in the preparation of the third suspension, 65.12 g of AN was added in the preparation of the fourth suspension, and 0.91 g of lithium hydroxide (dissolved in 197.60 g of pure water) was added in the preparation of the sixth suspension. Preparation of Binder Composition of Example 9

[0257] 6.37 g of lithium hydroxide was dissolved in 4.79 g of pure water. Then, 11.16 g of the lithium hydroxide solution was added to a 500 mL round-bottom flask containing 181.80 g of distilled water. This mixture was stirred at 200 rpm for 30 minutes to obtain the first suspension.

[0258] Furthermore, 20.45 g of AA and 6.10 g of MAA were added to the first suspension. This mixture was further stirred at 200 rpm for 30 minutes to obtain the second suspension.

[0259] 12.62 g of AM was dissolved in 48.57 g of pure water. Then, 61.19 g of the AM solution was added to the second suspension. This mixture was further stirred at 200 rpm for 30 minutes to obtain the third suspension.

[0260] Next, 66.71 g of AN was added to the third suspension. This mixture was stirred at 200 rpm for 40 minutes to obtain the fourth suspension.

[0261] The fourth suspension was heated to 60 °C and stirred at 60 rpm for 45 minutes. 0.11 g of a water-soluble free radical initiator (ammonium persulfate, APS; obtained from Aladin Industries Co., Ltd., China) was dissolved in 10.00 g of pure water, and 0.02 g of a reducing agent (sodium bisulfite; obtained from Tianjin Dama Chemical Reagent Factory, China) was dissolved in 16.19 g of pure water. 16.21 g of the sodium bisulfite solution was added to the fourth suspension and stirred for 10 minutes. 10.11 g of the APS solution was added dropwise to the mixture over 3 hours to form the fifth suspension. The fifth suspension was further stirred at 200 rpm at 65 °C for 20 hours.

[0262] After the reaction was completed, the temperature of the fifth suspension was lowered to 40 °C, and 1.66 g of lithium hydroxide (dissolved in 314.66 g of pure water) was added to the fifth suspension to adjust the pH to 7.24 to form the sixth suspension. The temperature of the sixth suspension was lowered to 30 °C, and a binder composition was prepared by filtration using a 200-mesh filter paper. The solid content of this binder composition was 14.76 wt.%.

[0263] Example 10 : A binder composition was prepared in the same manner as in Example 4, except that 7.89 g of AA and 5.63 g of MAA were added in the preparation of the second suspension, 16.90 g of AM was added in the preparation of the third suspension, and 82.24 g of AN was added in the preparation of the fourth suspension.

[0264] Example 11 : A binder composition was prepared in the same manner as in Example 4, except that 14.65 g of AA and 6.76 g of MAA were added in the preparation of the second suspension, 9.01 g of AM was added in the preparation of the third suspension, and 82.24 g of AN was added in the preparation of the fourth suspension.

[0265] Example 12 : In the preparation of the second suspension, 30.42 g of AA and 3.38 g of MAA were added. In the preparation of the third suspension, 11.27 g of AM was added. In the preparation of the fourth suspension, 67.60 g of AN was added. In the preparation of the sixth suspension, 6.12 g of lithium hydroxide (dissolved in 116.64 g of pure water) was added. Except for this, the binder composition was prepared in the same manner as in Example 4.

[0266] Example 13 : In the preparation of the second suspension, 5.63 g of AA and 5.63 g of MAA were added. In the preparation of the third suspension, 22.53 g of AM was added. In the preparation of the fourth suspension, 78.87 g of AN was added. Except for this, the binder composition was prepared in the same manner as in Example 4.

[0267] Example 14 : In the preparation of the second suspension, 27.04 g of AA and 5.63 g of MAA were added. In the preparation of the third suspension, 9.01 g of AM was added. In the preparation of the fourth suspension, 70.98 g of AN was added. In the preparation of the sixth suspension, 6.24 g of lithium hydroxide (dissolved in 116.64 g of pure water) was added. Except for this, the binder composition was prepared in the same manner as in Example 4.

[0268] Example 15: The binder composition was prepared in the same manner as in Example 4, except that in the preparation of the second suspension, 4.41 g of MAA was replaced with the same weight of 2-ethylacrylic acid.

[0269] Example 16: The binder composition was prepared in the same manner as in Example 4, except that in the preparation of the second suspension, 4.41 g of MAA was replaced with the same weight of crotonic acid.

[0270] Example 17: The binder composition was prepared in the same manner as in Example 5, except that in the preparation of the sixth suspension, 7.93 g of lithium hydroxide (dissolved in 101.39 g of pure water) was added.

[0271] Example 18: A binder composition was prepared in the same manner as in Example 6, except that 10.60 g of lithium hydroxide (dissolved in 74.14 g of pure water) was added in the preparation of the sixth suspension. Preparation of Binder Composition of Examples 19 - 21

[0272] The binder compositions of Examples 19 to 21 were prepared in the same manner as in Example 4.

[0273] Example 22: A binder composition was prepared in the same manner as in Example 4, except that 0.29 g of APS was dissolved in 82.68 g of pure water and 0.05 g was dissolved in 17.22 g of pure water so as to add 82.97 g of the APS solution and 17.27 g of the sodium bisulfite solution in the preparation of the fifth suspension. The weight average molecular weight of this binder composition was 105,780 g / mol, the number average molecular weight was 29,845 g / mol, and the polydispersity index was 3.54.

[0274] Example 23: A binder composition was prepared in the same manner as in Example 4, except that 0.11 g of APS was dissolved in 82.68 g of pure water and 0.02 g of sodium bisulfite was dissolved in 17.22 g of pure water so as to add 82.79 g of the APS solution and 17.24 g of the sodium bisulfite solution in the preparation of the fifth suspension. The weight average molecular weight of this binder composition was 193,226 g / mol, the number average molecular weight was 89,641 g / mol, and the polydispersity index was 2.16.

[0275] Example 24: A binder composition was prepared in the same manner as in Example 1, except that 0.29 g of APS was dissolved in 82.68 g of pure water and 0.05 g of sodium bisulfite was dissolved in 17.22 g of pure water so as to add 82.97 g of the APS solution and 17.27 g of the sodium bisulfite solution in the preparation of the fifth suspension. The weight average molecular weight of the binder composition was 118,528 g / mol, the number average molecular weight was 30,523 g / mol, and the polydispersity index was 3.88.

[0276] Example 25. In the preparation of the fifth suspension, except that 0.11 g of APS was dissolved in 82.68 g of pure water and 0.02 g of sodium bisulfite was dissolved in 17.22 g of pure water, and 82.79 g of the APS solution and 17.24 g of the sodium bisulfite solution were added, a binder composition was prepared in the same manner as in Example 1. The weight-average molecular weight of the binder composition was 186,744 g / mol, the number-average molecular weight was 92,140 g / mol, and the polydispersity index was 2.03. Comparative Example 1

[0277] In the preparation of the first suspension, 1.10 g of lithium hydroxide (dissolved in 3.85 g of pure water) was added. In the preparation of the second suspension, 7.21 g of AA was added. In the preparation of the third suspension, 22.75 g of AM was added. In the preparation of the fourth suspension, 83.83 g of AN was added. In the preparation of the sixth suspension, except that 1.5 g of lithium hydroxide (dissolved in 116.64 g of pure water) was added, a binder composition was prepared in the same manner as in the first example. Comparative Example 2

[0278] In the preparation of the second suspension, 37.47 g of AA was added. In the preparation of the third suspension, 7.11 g of AM was added. In the preparation of the fourth suspension, 73.22 g of AN was added. In the preparation of the sixth suspension, except that 7.34 g of lithium hydroxide (dissolved in 116.64 g of pure water) was added, a binder composition was prepared in the same manner as in Example 1. Comparative Example 3

[0279] In the preparation of the second suspension, 24.50 g of AA and 6.88 g of MAA were added. In the preparation of the third suspension, 22.75 g of AM was added. In the preparation of the fourth suspension, 66.86 g of AN was added. In the preparation of the sixth suspension, except that 4.95 g of lithium hydroxide (dissolved in 116.64 g of pure water) was added, a binder composition was prepared in the same manner as in Example 4. Comparative Example 4

[0280] In the preparation of the second suspension, 10.09 g of AA and 5.16 g of MAA were added. In the preparation of the third suspension, 7.11 g of AM was added. In the preparation of the fourth suspension, 90.20 g of AN was added. Otherwise, the binder composition was prepared in the same manner as in Example 4. Comparative Example 5

[0281] In the preparation of the first suspension, 0.8 g of lithium hydroxide (dissolved in 3.85 g of pure water) was added. In the preparation of the second suspension, 4.32 g of AA and 0.86 g of MAA were added. In the preparation of the third suspension, 12.79 g of AN was added. In the preparation of the fourth suspension, 92.86 g of AN was added. In the preparation of the sixth suspension, 1.40 g of lithium hydroxide (dissolved in 116.64 g of pure water) was added. Otherwise, the binder composition was prepared in the same manner as in Example 4. Comparative Example 6

[0282] In the preparation of the second suspension, 28.10 g of AA and 10.33 g of MAA were added. In the preparation of the third suspension, 7.11 g of AM was added. In the preparation of the fourth suspension, 73.75 g of AN was added. In the preparation of the sixth suspension, 7.38 g of lithium hydroxide (dissolved in 116.64 g of pure water) was added. Otherwise, the binder composition was prepared in the same manner as in Example 4. Comparative Example 7

[0283] In the preparation of the second suspension, 21.62 g of AA and 6.88 g of MAA were added. In the preparation of the third suspension, 4.26 g of AM was added. In the preparation of the fourth suspension, 82.77 g of AN was added. In the preparation of the sixth suspension, 6.50 g of lithium hydroxide (dissolved in 116.64 g of pure water) was added. Otherwise, the binder composition was prepared in the same manner as in Example 4. Comparative Example 8

[0284] In the preparation of the second suspension, 5.95 g of AA and 5.96 g of MAA were added. In the preparation of the third suspension, 33.99 g of AM was added. In the preparation of the fourth suspension, 72.69 g of AN was added. Except for these, the binder composition was prepared in the same manner as in Example 4. Comparative Example 9

[0285] In the preparation of the second suspension, 36.03 g of AA and 17.21 g of MAA were added. In the preparation of the third suspension, 17.06 g of AM was added. In the preparation of the fourth suspension, 56.24 g of AN was added. In the preparation of the sixth suspension, 9.69 g of lithium hydroxide (dissolved in 116.64 g of pure water) was added. Except for these, the binder composition was prepared in the same manner as in Example 4. Comparative Example 10

[0286] In the preparation of the second suspension, 17.29 g of AA, 5.16 g of MAA and 8.51 g of methyl acrylate (MA) were added. In the preparation of the third suspension, 14.22 g of AM was added. In the preparation of the fourth suspension, 74.28 g of AN was added. Except for these, the binder composition was prepared in the same manner as in Example 4. Preparation of Cathodes of Examples 2 - 18, 22 - 25 and Comparative Examples 1 - 10

[0287] The positive electrodes of Examples 2 to 18, 22 to 25 and Comparative Examples 1 to 10 were fabricated in the same manner as in Example 1. Preparation of Cathode of Example 19

[0288] The positive electrode of Example 19 was fabricated 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 Bomo Technology Co., Ltd., China). Preparation of Cathode of Example 20

[0289] The positive electrode of Example 20 was fabricated in the same manner as in Example 1, except that 28.2 g of NMC622 was replaced with the same weight of LiCoO 2 (obtained from Tianjin Bamao Technology Co., Ltd., China). Preparation of Cathode of Example 21

[0290] The positive electrode of Example 21 was prepared in the same manner as in Example 1, except that 28.2 g of NMC622 was replaced with the same weight of LiFePO 4 (obtained from Xiamen Tungsten Industry Co., Ltd., China). Preparation of Anodes of Examples 2 - 25 and Comparative Examples 1 - 10

[0291] The negative electrodes of Examples 2 to 25 and Comparative Examples 1 to 10 were prepared in the same manner as in Example 1. Assembly of Coin Cells of Examples 2 - 25 and Comparative Examples 1 - 10

[0292] The coin cells of Examples 2 to 25 and Comparative Examples 1 to 10 were assembled in the same manner as in Example 1. Electrochemical Measurement of Examples 2 - 25 and Comparative Examples 1 - 10

[0293] The electrochemical performance of the coin cells of Examples 2 to 25 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. Also, only the capacity retention rate after 100 cycles of the coin cells of Examples 1 to 11, 13, 15 to 16, 19 to 21 and Comparative Examples 1 to 10 was measured, and the test results are shown in Table 2 below.

Table 1-1

Table 1-2

Table 2-1

Table 2-2

[0294] Although 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 present invention. In some embodiments, the method can include a number of steps not mentioned herein. In other embodiments, the method does not include, or substantially does not include, any steps not listed herein. There are variations and modifications from the described embodiments. The appended claims are intended to cover all such modifications and variations as being within the scope of the present invention. The invention described in the original claims of the present application is appended below. [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 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, 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,The binder composition according to [1], which 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, difluoro maleate, nonyl hydrogen maleate, decyl hydrogen maleate, dodecyl hydrogen maleate, octadecyl hydrogen maleate, fluoroalkyl hydrogen maleate, maleic anhydride, methyl maleic anhydride, dimethyl maleic anhydride, acrylic anhydride, methacrylic anhydride, methacrolein, methacryloyl chloride, methacryloyl fluoride, methacryloyl bromide, or a combination thereof., [3] The proportion of the structural unit (a) derived from the carboxylic acid group-containing monomer in the copolymer is about 7% to about 25% in moles based on the total number of monomer units of the copolymer in the binder composition. The binder composition according to [1]. [4] The amide group-containing monomer is selected from the group consisting of methacrylamide, N-methylmethacrylamide, N-ethylmethacrylamide, N-n-propylmethacrylamide, N-isopropylmethacrylamide, N-n-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, diacetonemethacrylamide, methacryloylmorpholine, and combinations thereof, the binder composition according to [1]. [5] The proportion of the structural unit (b) derived from the amide group-containing monomer in the copolymer is about 4% to about 17% in moles based on the total number of moles of monomer units in the copolymer in the binder composition, the binder composition according to [1]. [6] 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, the binder composition according to [1]. [7] The proportion of the structural unit (c) derived from the nitrile group-containing monomer in the copolymer is about 65% to about 80% in terms of mole, based on the total number of moles of monomer units in the copolymer in the binder composition, the binder composition according to [1]. [8] The dispersion medium is water, the binder composition according to [1]. [9] The binder composition according to [8], wherein the dispersion medium further contains 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] The total proportion of the structural unit (a) derived from the carboxylic acid group-containing monomer and the structural unit (b) derived from the amide group-containing monomer in the copolymer is about 18% to about 35% in terms of mole, based on the total number of moles of monomer units in the copolymer in the binder composition, the binder composition according to [1].

[11] The molar ratio of the structural unit (c) derived from the nitrile group-containing monomer to the total of the structural unit (a) derived from the carboxylic acid group-containing monomer and the structural unit (b) derived from the amide group-containing monomer in the copolymer is about 1.5 to about 4, the binder composition according to [1].

[12] The molar ratio of the structural unit (c) derived from the nitrile group-containing monomer to the total of the structural unit (a) derived from the carboxylic acid group-containing monomer and the structural unit (b) derived from the amide group-containing monomer in the copolymer is about 5 to about 15, the binder composition according to [1].

[13] The pH of the binder composition is about 7 to about 9, the binder composition according to [1].

[14] The viscosity of the binder composition is about 10,000 mPa·s to about 50,000 mPa·s, the binder composition according to [1].

[15] The electrolyte swelling of the binder composition is about 2% to about 4%, the binder composition according to [1].

[16] The adhesion strength between the binder composition and the current collector is about 2 N / cm to about 4 N / cm, the binder composition according to [1].

[17] The solid content of the binder composition is about 12% to about 18% by weight, based on the total weight of the binder composition, the binder composition according to [1].

[18] An electrode for a secondary battery, comprising an electrode active material, a conductive agent, and the binder composition described in [1].

[19] The electrode for a secondary battery described in

[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.

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, and the proportion of the structural unit (a) derived from the carboxylic acid group-containing monomer in the copolymer is 7% to 25% in terms of mole based on the total number of moles of monomer units of the copolymer in the binder composition, and the proportion of the structural unit (b) derived from the amide group-containing monomer in the copolymer is 4% to 17% in terms of mole based on the total number of moles of monomer units of the copolymer in the binder composition, and the proportion of the structural unit (c) derived from the nitrile group-containing monomer in the copolymer is 65% to 80% in terms of mole based on the total number of moles of monomer units of the copolymer in the binder composition, and the binder composition does not contain a structural unit derived from an ester group-containing monomer. A binder composition for a secondary battery electrode.

2. 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, 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,The binder composition according to claim 1, 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, difluoro maleate, nonyl hydrogen maleate, decyl hydrogen maleate, dodecyl hydrogen maleate, octadecyl hydrogen maleate, fluoroalkyl hydrogen maleate, maleic anhydride, methyl maleic anhydride, dimethyl maleic anhydride, acrylic anhydride, methacrylic anhydride, methacrolein, methacryloyl chloride, methacryloyl fluoride, methacryloyl bromide, or a combination thereof.,

3. The binder composition according to claim 1, wherein the secondary battery is a lithium ion battery.

4. The binder composition according to claim 1, wherein the amide group-containing monomer is selected from the group consisting of methacrylamide, N-methylmethacrylamide, N-ethylmethacrylamide, N-n-propylmethacrylamide, N-isopropylmethacrylamide, N-n-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-dimethylaminopropylmethacrylamide, N,N-dimethylaminoethylmethacrylamide, N,N-dimethylolmethacrylamide, diacetonemethacrylamide, methacryloylmorpholine, and combinations thereof.

5. 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. The binder composition according to claim 1.

6. The dispersion medium is water. The binder composition according to claim 1.

7. The binder composition according to claim 6, wherein the dispersion medium further contains 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.

8. The total proportion of the structural unit (a) derived from the carboxylic acid group-containing monomer and the structural unit (b) derived from the amide group-containing monomer in the copolymer is 18% to 35% in terms of mole based on the total number of monomer units in the copolymer of the binder composition. The binder composition according to claim 1.

9. The molar ratio of the structural unit (c) derived from the nitrile group-containing monomer to the total of the structural unit (a) derived from the carboxylic acid group-containing monomer and the structural unit (b) derived from the amide group-containing monomer in the copolymer is 1.5 to 4. The binder composition according to claim 1.

10. The molar ratio of the structural unit (c) derived from the nitrile group-containing monomer and the total of the structural unit (a) derived from the carboxylic acid group-containing monomer to the structural unit (b) derived from the amide group-containing monomer in the copolymer is 5 to 15. The binder composition according to claim 1.

11. The pH of the binder composition is 7 to 9. The binder composition according to claim 1.

12. The viscosity of the binder composition is 10,000 mPa·s to 50,000 mPa·s. The binder composition according to claim 1.

13. The electrolyte swelling of the binder composition is 2% to 4%. The binder composition according to claim 1.

14. The solid content of the binder composition is 12% to 18% by weight based on the total weight of the binder composition. The binder composition according to claim 1.

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

16. The peel strength between the current collector and the electrode layer is in the range of 1.0 N / cm to 8.0 N / cm. The electrode for a secondary battery according to claim 15.

17. The electrode active material is LiCoO 2 、LiNiO 2 、LiNi x Mn y O 2 、Li 1+z Ni x Mn y Co 1-x-y O 2 、LiNi x Co y Al z O 2 、LiV 2 O 5 、LiTiS 2 、LiMoS 2 、LiMnO 2 、LiCrO 2 、LiMn 2 O 4 、Li 2 MnO 3 、LiFeO 2 、LiFePO 4 、Li 4 Ti 5 O 12 、LiNi 0.92 Mn 0.04 Co 0.04 O 2 、Li 1+d Ni a Mn b Co c Al (1-a-b-c) O 2 、and is selected from the group consisting of combinations thereof, each x is independently 0.2 to 0.9, each y is independently 0.1 to 0.45, each z is independently 0 to 0.2, -0.2 ≦ d ≦ 0.2, 0 ≦ a < 1, 0 ≦ b < 1, 0 ≦ c < 1, and a + b + c ≦ 1, the electrode according to claim 15.

18. A binder composition for a secondary battery electrode containing a copolymer, wherein the copolymer contains 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, and the proportion of the structural unit (a) derived from the carboxylic acid group-containing monomer in the copolymer is 7% to 25% in terms of moles based on the total number of moles of monomer units of the copolymer in the binder composition, and the proportion of the structural unit (b) derived from the amide group-containing monomer in the copolymer is 4% to 17% in terms of moles based on the total number of moles of monomer units of the copolymer in the binder composition, and the proportion of the structural unit (c) derived from the nitrile group-containing monomer in the copolymer is 65% to 80% in terms of moles based on the total number of moles of monomer units of the copolymer in the binder composition, and the binder composition does not contain a structural unit derived from an ester group-containing monomer. A binder composition for a secondary battery electrode.

19. The adhesion strength between the binder composition and the current collector is 2 N / cm to 4 N / cm. The binder composition according to claim 18.

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