Binder composition for secondary battery

Abstract

The aqueous binder composition for 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 become widely used in various applications, particularly in household appliances, due to their excellent energy density, long cycle life, and high discharge capacity. The rapid market development of electric vehicles (EVs) and grid energy storage has made high-performance and low-cost LIBs one of the most promising options for large-scale energy storage devices at present.

[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] In order 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 such problems, attempts have been made to replace conventional PVDF with a more environmentally friendly water-soluble binder material, or to utilize the known advantages of PVDF as a binder for electrode slurries without using organic solvents that require specific recovery processes during manufacturing.

[0006] Known aqueous binders such as carboxymethyl cellulose (CMC) and styrene-butadiene rubber (SBR) exhibit only slight adhesion ability and poor cycle life. In particular, SBR requires a thickening agent to adjust the binder viscosity. Moreover, SBR has high swelling properties and exhibits unfavorable aggregation characteristics, resulting in non-uniform dispersion, increased electrode resistance, and performance degradation. 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 voltages. Therefore, their application to the cathode in particular is somewhat limited.

[0007] EP Patent Application Publication No. 255293B1 discloses an aqueous electrode slurry for a lithium-ion-containing electrochemical cell. This slurry is composed of PVDF and SBR in an aqueous solution, and at least one combination of polyacrylic acid (PAA) and CMC, and an electrochemically active material. The proposed invention attempts to combine an aqueous slurry and PVDF that enables easier handling, reduced environmental pollution, and cost reduction while maintaining the known chemical and electrochemical advantages of PVDF as a binder, namely, electrochemical stability, life stability, and a decrease in the binder content enabling a higher C-rate. Despite the fact that a slurry free of organic solvents can be prepared based on the proposed invention, the slurry is nevertheless composed of a fluorine-containing binder material. 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 characteristics are sustained, and that contributes to excellent battery electrochemical performance, is always required.

Summary of the Invention

[0009] The aforementioned needs are met by various aspects and embodiments disclosed herein. Provided herein is a binder composition for a secondary battery electrode comprising a copolymer and a 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. Further, 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] FIG. 1 is a flowchart of an embodiment showing steps for preparing a binder composition.

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 place and attach it to a conductive metal part 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, a 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 high molecular weight compound prepared by polymerizing the same or different types of monomers. 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 the same type of monomers.

[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 obtained by removing a hydrogen atom from a saturated, unbranched or branched aliphatic hydrocarbon, having the general formula C n H 2n+1 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 monocyclic or multiple condensed 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, which 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 groups, C 2 ~C 30 alkenyl groups, C 2 ~C 30 alkynyl groups, C 1 ~C 30 alkylene groups, C 2 ~C 30 alkenylene groups, 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 a heteroatom or a substituent. 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 a chemical moiety means that at least one hydrogen atom of the compound or chemical moiety is substituted 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 by substituents selected from such groups. All chemical groups disclosed herein can be substituted unless otherwise specified.

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

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

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

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

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

[0033] The term "current collector" refers to any conductive substrate that is in contact with 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 current collectors include a single conductive metal layer or substrate, and a single conductive metal layer or substrate having a conductive coating layer thereon such as a carbon black-based coating layer. The conductive metal layer or substrate may be in the form of a foil or a porous body having a three-dimensional network structure, and may be a 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)) 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 distribution of molecular weights 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 falls 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-hours. 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%, 2%, 5%, or in some cases 10 - 20%. Lower limit value R L and upper limit value R U Whenever a numerical range with a lower limit 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 then 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 promote 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. Therefore, the energy consumption and manufacturing cost in the manufacturing process increase. Thus, 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 some of the representative aqueous binders that are already used in large-scale commercial applications. However, these binders have limitations in terms of binding force 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, their 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 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. FIG. 1 is a flowchart of an embodiment showing the steps of method 100 for preparing the binder composition. The binder composition described herein has been found to exhibit improved adhesion ability and flexibility, 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 include a hydrophilic solvent selected from the group consisting of ethanol, isopropanol, n-propanol, tert-butanol, n-butanol, dimethylacetamide (DMAc), dimethylformamide (DMF), N-methylpyrrolidone (NMP), methyl ethyl ketone (MEK), ethyl acetate (EA), butyl acetate (BA), and combinations thereof. In some embodiments, the dispersion medium is free of water, ethanol, isopropanol, n-propanol, tert-butanol, n-butanol, dimethylacetamide (DMAc), dimethylformamide (DMF), N-methylpyrrolidone (NMP), methyl ethyl ketone (MEK), ethyl acetate (EA), or butyl acetate (BA).

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

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

[0060] The structural unit (a) is derived from a carboxylic acid group-containing monomer. Any monomer having at least one carboxylic acid group may be used as the carboxylic acid group-containing monomer without particular limitation. In 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 a combination thereof. In certain embodiments, the carboxylic acid group-containing monomer is 2-ethylacrylic acid, isocrotonic acid, cis-2-pentenoic acid, trans-2-pentenoic acid, angelic acid, tiglic acid, 3,3-dimethylacrylic acid, 3-propylacrylic acid, trans-2-methyl-3-ethylacrylic acid, cis-2-methyl-3-ethylacrylic acid, 3-isopropylacrylic acid, trans-3-methyl-3-ethylacrylic acid, cis-3-methyl-3-ethylacrylic acid, 2-isopropylacrylic acid, trimethylacrylic acid, 2-methyl-3,3-diethylacrylic acid, 3-butylacrylic acid, 2-butylacrylic acid, 2-pentylacrylic acid, 2-methyl-2-hexenoic acid, trans-3-methyl-2-hexenoic acid, 3-methyl-3-propylacrylic acid, 2-ethyl-3-propylacrylic acid, 2,3-diethylacrylic acid, 3,3-diethylacrylic acid, 3-methyl-3-hexylacrylic acid, 3-methyl-3-tert-butylacrylic acid, 2-methyl-3-pentylacrylic acid, 3-methyl-3-pentylacrylic acid, 4-methyl-2-hexenoic acid, 4-ethyl-2-hexenoic acid, 3-methyl-2-ethyl-2-hexenoic acid, 3-tert-butylacrylic acid, 2,3-dimethyl-3-ethylacrylic acid, 3,3-dimethyl-2-ethylacrylic acid, 3-methyl-3-isopropylacrylic acid, 2-methyl-3-isopropylacrylic acid, trans-2-octenoic acid, cis-2-octenoic acid, trans-2-decenoic acid, α-acetoxyacrylic acid, β-trans-allyloxyacrylic acid, α-chloro-β-E-methoxyacrylic acid, or a combination thereof.In some embodiments, the carboxylic acid group-containing monomer is methyl maleate, dimethyl maleate, phenyl maleate, bromo maleate, 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.

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

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

[0063] In some embodiments, each of the first suspension and the second suspension is independently 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 10 minutes to about 35 minutes, about 15 minutes to about 35 minutes, about 20 minutes to about 35 minutes, or about 25 minutes to about 35 minutes. In some embodiments, each of the first suspension and the second suspension is independently 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.

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

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

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

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

[0068] 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.

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

[0070] In some embodiments, the proportion of the amide group-containing monomer is less than 34%, less than 33%, less than 32%, less than 31%, less than 30%, less than 29%, less than 28%, less than 27%, less than 26%, less than 25%, less than 24%, less than 23%, less than 22%, less than 21%, less than 20%, less than 19%, less than 18%, less than 17%, or less than 16% by weight based on the total weight of the monomers added in the preparation of the binder composition. In some embodiments, the proportion of the amide group-containing monomer is more than 15%, more than 16%, more than 17%, more than 18%, more than 19%, more than 20%, more than 21%, more than 20%, 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 third suspension is stirred for a time of about 5 minutes to about 60 minutes, about 5 minutes to about 55 minutes, about 5 minutes to about 50 minutes, about 10 minutes to about 50 minutes, about 15 minutes to about 50 minutes, about 20 minutes to about 50 minutes, about 25 minutes to about 50 minutes, about 30 minutes to about 50 minutes, or about 35 minutes to about 50 minutes. In some embodiments, the third suspension is stirred for a time less than 60 minutes, less than 55 minutes, less than 50 minutes, less than 45 minutes, less than 40 minutes, less than 35 minutes, less than 30 minutes, less than 25 minutes, less than 20 minutes, less than 15 minutes, or less than 10 minutes. In some embodiments, the third suspension is stirred for 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, longer than 40 minutes, longer than 45 minutes, longer than 50 minutes, or longer than 55 minutes.

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

[0073] In some embodiments, the temperature of the third 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.

[0074] In some embodiments, the temperature of the third 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. In some embodiments, the temperature of the third 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.

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

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

[0077] The structural unit (c) is derived from a nitrile group-containing monomer. 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.

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

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

[0080] In certain embodiments, a combination of a carboxylic acid group-containing monomer, a nitrile group-containing monomer, and an amide group-containing monomer may be added to the first suspension to form the second suspension without forming 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, third, or 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.

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

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

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

[0084] In one embodiment, the carboxyl group-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 group-containing monomer is 2-ethyl acrylate, isocrotonate, cis-2-pentenoate, trans-2-pentenoate, angelate, tiglate, 3,3-dimethyl acrylate, 3-propyl acrylate, trans-2-methyl-3-ethyl acrylate, cis-2-methyl-3-ethyl acrylate, 3-isopropyl acrylate, trans-3-methyl-3-ethyl acrylate, cis-3-methyl-3-ethyl acrylate, 2-isopropyl acrylate, trimethyl acrylate, 2-methyl-3,3-diethyl acrylate, 3-butyl acrylate, 2-butyl acrylate, 2-pentyl acrylate, 2-methyl-2-hexenoate, trans-3-methyl-2-hexenoate, 3-methyl-3-propyl acrylate, 2-ethyl-3-propyl acrylate, 2,3-diethyl acrylate, 3,3-diethyl acrylate, 3-methyl-3-hexyl acrylate, 3-methyl-3-tert-butyl acrylate, 2-methyl-3-pentyl acrylate, 3-methyl-3-pentyl acrylate, 4-methyl-2-hexenoate, 4-ethyl-2-hexenoate, 3-methyl-2-ethyl-2-hexenoate, 3-tert-butyl acrylate. 2,3-dimethyl-3-ethyl acrylate, 3,3-dimethyl-2-ethyl acrylate, 3-methyl-3-isopropyl acrylate, 2-methyl-3-isopropyl acrylate, trans-2-octenoate, cis-2-octenoate, trans-2-decenoate, α-acetoxy acrylate, β-trans-allyloxy acrylate, α-chloro-β-E-methoxy acrylate 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.

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

[0086] 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 0.8, from about 0 to about 0.78, from about 0 to about 0.76, from about 0 to about 0.74, from about 0 to about 0.72, from about 0 to about 0.7, from about 0 to about 0.68, from about 0 to about 0.66, from about 0 to about 0.64, from about 0 to about 0.62, from about 0 to about 0.6, from about 0 to about 0.58, from about 0 to about 0.56, from about 0 to about 0.54, from about 0 to about 0.52, from about 0 to about 0.5, from about 0 to about 0.48, from about 0 to about 0.46, from about 0 to about 0.44, from about 0 to about 0.42, from about 0 to about 0.4, from about 0 to about 0.38, from about 0 to about 0.36, from about 0 to about 0.34, from about 0 to about 0.32, from about 0 to about 0.3, from about 0.02 to about 0.3, from about 0.04 to about 0.3, from about 0.06 to about 0.3, from about 0.08 to about 0.3, from about 0.1 to about 0.3, from about 0.05 to about 0.5, or from about 0.05 to about 0.4.

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

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

[0089] 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%, 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 terms of mole, based on the total number of moles of the monomers in the composition. In some embodiments, the proportion of the carboxylic acid group-containing monomer is 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%, 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%, or more than 28% in terms of mole, based on the total number of moles of the monomers in the composition.

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

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

[0092] In some embodiments, the proportion of the nitrile group-containing monomer is about 10% to about 30 mol%, about 11% to about 30 mol%, about 12% to about 30 mol%, about 13% to about 30 mol%, about 14% to about 30 mol%, about 15% to about 30 mol%, about 16% to about 30 mol%, about 17% to about 30 mol%, about 18% to about 30 mol%, about 19% to about 30 mol%, about 20% to about 30 mol%, about 20 to about 29 mol%, about 20 to about 28 mol%, about 20% to about 27 mol%, about 20% to about 26 mol%, about 20% to about 25 mol%, about 11% to about 25 mol%, about 12% to about 25 mol%, about 13% to about 25 mol%, about 14% to about 25 mol%, about 15% to about 25 mol%, about 16% to about 27 mol%, about 17% to about 27 mol%, about 18% to about 27 mol%, about 19% to about 27 mol%, or about 10% to about 27 mol% based on the total number of moles of monomers contained in the composition.

[0093] In some embodiments, the proportion of the nitrile 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% in moles, based on the total number of moles of the monomers in the composition. In some embodiments, the proportion of the nitrile 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%, or more than 28% in moles, based on the total number of moles of the monomers in the composition.

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

[0095] In some embodiments, the proportion of the amide group-containing monomer is less than 35 mol%, less than 34 mol%, less than 33 mol%, less than 32 mol%, less than 31 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 18 mol%, less than 16 mol%, less than 14 mol%, or less than 12 mol% based on the total number of moles of the monomers in the composition. In some embodiments, the proportion of the amide group-containing monomer 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 27 mol%, more than 28 mol%, more than 29 mol%, more than 30 mol%, more than 32 mol%, or more than 34 mol% based on the total number of moles of the monomers in the composition.

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

[0097] In other embodiments, the fifth suspension is formed by sequentially adding a portion of the initiator solution into the fourth suspension. Stirring or dispersion may be employed during the addition.

[0098] The polymerization occurring in the present invention follows a radical mechanism in which an 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.

[0099] 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 is 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 Acids, etc. and peroxide-based initiators such as hydrogen peroxide, t-butyl hydroperoxide, succinic peroxide and combinations thereof.

[0100] 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.

[0101] In some embodiments, the reducing agent solution is prepared by dissolving the reducing agent in water. In some embodiments, the reducing agent is 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 , Ho rhamnaldehyde sulfoxylate metal salts, burgolite FF6M , and and combinations thereof.

[0102] 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 from about 0.2 to about 10, from about 0.2 to about 9, from about 0.2 to about 8, from about 0.2 to about 7, from about 0.2 to about 6, from about 0.2 to about 5, from about 0.3 to about 5, from about 0.4 to about 5, from about 0.5 to about 5, from about 0.6 to about 5, from about 0.7 to about 5, from about 0.8 to about 5, from about 0.9 to about 5, from about 1 to about 5, from about 0.5 to about 4.5, from about 0.5 to about 4, from about 0.6 to about 3.5, from about 0.6 to about 0.3, from about 0.8 to about 3, or from about 0.2 to about 1.

[0103] 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 .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 greater than 0.2, greater than 0.4, greater than 0.6, greater than 0.8, greater than 1, greater than 1.2, greater than 1.4, greater than 1.6, greater than 1.8, greater than 2, greater than 2.2, greater than 2.4, greater than 2.6, greater than 2.8, greater than 3, greater than 3.2, greater than 3.4, greater than 3.6, greater than 3.8, greater than 4, greater than 4.2, greater than 4.4, greater than 4.6, greater than 4.8, greater than 5, greater than 6, greater than 7, greater than 8, or greater than 9.

[0104] The coincidence 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.

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

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

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

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

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

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

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

[0112] In some embodiments, the proportion of the water-soluble free radical initiator is about 0.005% to about 0.05%, about 0.0075% to about 0.05%, about 0.01% to about 0.05%, about 0.01% to about 0.048%, about 0.01% to about 0.046%, about 0.01% to about 0.044%, about 0.01% to about 0.042%, about 0.01% to about 0.04%, about 0.01% to about 0.038%, about 0.01% to about 0.036%, about 0.01% to about 0.034%, about 0.01% to about 0.032%, about 0.01% to about 0.03%, about 0.012% to about 0.03%, about 0.014% to about 0.03%, about 0.016% to about 0.03%, about 0.01% to about 0.028%, about 0.016% to about 0.026%, about 0.018% to about 0.026%, or about 0.02% to about 0.026% by weight 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.

[0113] In some embodiments, the proportion of the water-soluble free radical initiator is less than 0.05%, less than 0.048%, less than 0.046%, less than 0.044%, less than 0.042%, less than 0.04%, less than 0.038%, less than 0.036%, less than 0.034%, less than 0.032%, less than 0.03%, less than 0.028%, less than 0.026%, less than 0.024%, less than 0.022%, less than 0.02%, less than 0.018%, less than 0.016%, less than 0.014%, less than 0.012%, less than 0.01%, less than 0.008%, or less than 0.006% by weight, based on the total weight of the monomers added in the preparation of the binder composition. In some embodiments, the proportion of the water-soluble free radical initiator is more than 0.005%, more than 0.0075%, more than 0.01%, more than 0.012%, more than 0.014%, more than 0.016%, more than 0.018%, more than 0.02%, more than 0.022%, more than 0.024%, more than 0.026%, more than 0.028%, more than 0.03%, more than 0.032%, more than 0.034%, more than 0.036%, more than 0.038%, more than 0.04%, more than 0.042%, more than 0.044%, more than 0.046%, or more than 0.048% by weight, 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 about 0.001% to about 0.03%, about 0.0025% to about 0.03%, about 0.005% to about 0.03%, about 0.005% to about 0.029%, about 0.005% to about 0.028%, about 0.005% to about 0.027%, about 0.005% to about 0.026%, about 0.005% to about 0.025%, about 0.005% to about 0.024%, about 0.005% to about 0.023%, about 0.005% to about 0.022%, about 0.005% to about 0.021%, about 0.005% to about 0.02%, about 0.005% to about 0.019%, about 0.005% to about 0.018%, about 0.005% to about 0.017%, about 0.005% to about 0.016%, about 0.005% to about 0.015%, about 0.006% to about 0.015%, about 0.007% to about 0.015%, about 0.007% to about 0.02%, or about 0.007% to about 0.025% by weight based on the total weight of the monomers added in the preparation of the binder composition.

[0115] In some embodiments, the proportion of the reducing agent is less than 0.03% by weight, less than 0.029% by weight, less than 0.028% by weight, less than 0.027% by weight, less than 0.026% by weight, less than 0.025% by weight, less than 0.024% by weight, less than 0.023% by weight, less than 0.022% by weight, less than 0.021% by weight, less than 0.02% by weight, less than 0.019% by weight, less than 0.018% by weight, less than 0.017% by weight, less than 0.016% by weight, less than 0.015% by weight, less than 0.014% by weight, less than 0.013% by weight, less than 0.012% by weight, less than 0.011% by weight, less than 0.01% by weight, less than 0.008% by weight, less than 0.006% by weight, or less than 0.004% 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 reducing agent is more than 0.001% by weight, more than 0.0025% by weight, more than 0.005% by weight, more than 0.006% by weight, more than 0.007% by weight, more than 0.008% by weight, more than 0.009% by weight, more than 0.01% by weight, more than 0.011% by weight, more than 0.012% by weight, more than 0.013% by weight, more than 0.014% by weight, more than 0.015% by weight, more than 0.016% by weight, more than 0.017% by weight, more than 0.018% by weight, more than 0.019% by weight, more than 0.02% by weight, more than 0.021% by weight, more than 0.022% by weight, more than 0.023% by weight, more than 0.024% by weight, more than 0.025% by weight, more than 0.026% by weight, more than 0.027% by weight, or more than 0.028% by weight, based on the total weight of the monomers added in the preparation of the binder composition.

[0116] In some embodiments, the neutralizing solution is prepared by dissolving a neutralizing agent in water. In some embodiments, the sixth suspension is formed by dropwise adding the neutralizing 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.

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

[0118] In some embodiments, the total proportion of the neutralizing agent is about 35% to about 68%, about 35% to about 66%, about 35% to about 64%, about 35% to about 62%, about 35% to about 60%, about 35% to about 59%, about 35% to about 58%, about 35% to about 57%, about 35% to about 56%, about 35% to about 55%, about 35% to about 54%, about 35% to about 53%, about 35% to about 52%, about 35% to about 51%, about 35% to about 50%, about 36% to about 50%, about 37% to about 50%, about 38% to about 50%, about 39% to about 50%, about 40% to about 50%, about 35% to about 45%, or about 42% to about 52% in terms of moles based on the total number of moles of the monomer units in the copolymer of the binder composition.

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

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

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

[0122] In some embodiments, the fifth suspension is stirred for a time of less than 6 hours, less than 5.75 hours, less than 5.5 hours, less than 5.25 hours, less than 5 hours, less than 4.75 hours, less than 4.5 hours, less than 4.25 hours, less than 4 hours, less than 3.75 hours, less than 3.5 hours, less than 3.25 hours, less than 3 hours, less than 2.75 hours, less than 2.5 hours, less than 2.25 hours, less than 2 hours, less than 1.75 hours, or less than 1.5 hours while the addition and neutralization of the neutralization solution are being carried out. In some embodiments, the fifth suspension is stirred for a time of 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, longer than 3.75 hours, longer than 4 hours, longer than 4.25 hours, longer than 4.5 hours, longer than 4.75 hours, longer than 5 hours, longer than 5.25 hours, or longer than 5.5 hours while the addition and neutralization of the neutralization solution are being carried out.

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

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

[0125] In some embodiments, by filtering the sixth suspension in step 107, a binder composition is formed.

[0126] 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 because it may disrupt the dispersion of the binder composition.

[0127] In some embodiments, the structural unit (a) derived from the 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 the 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 the alkali metal that forms the alkali metal carboxylate include lithium, sodium, and potassium. In some embodiments, the structural unit (a) contains an ammonium carboxylate group.

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

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

[0130] In some embodiments, the proportion of structural unit (a) in the copolymer is about 33% to about 70%, about 33% to about 69%, about 33% to about 68%, about 33% to about 67%, about 33% to about 66%, about 33% to about 65%, about 33% to about 64%, about 33% to about 63%, about 33% to about 62%, about 33% to about 61%, about 33% to about 60%, about 33% to about 59%, about 33% to about 58%, about 33% to about 57%, about 33% to about 56%, about 33% to about 55%, about 33% to about 54%, about 33% to about 53%, about 33% to about 52%, about 33% to about 51%, about 33% to about 50%, about 34% to about 50%, about 35% to about 50%, about 36% to about 50%, about 37% to about 50%, about 38% to about 50%, about 39% to about 50%, about 40% to about 50%, about 35% to about 60%, or about 40% to about 55% in terms of moles, based on the total number of moles of monomer units in the copolymer in the binder composition.

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

[0132] In some embodiments, the proportion of structural unit (b) in the copolymer is about 10% to about 35%, about 10% to about 34%, about 10% to about 33%, about 10% to about 32%, about 10% to about 31%, about 10% to about 30%, about 11% to about 30%, about 12% to about 30%, about 13% to about 30%, about 14% to about 30%, about 15% to about 30%, about 16% to about 30%, about 17% to about 30%, about 18% to about 30%, about 19% to about 30%, about 20% to about 30%, about 20% to about 29%, about 20% to about 28%, about 20% to about 27%, about 20% to about 26%, about 20% to about 25%, about 15% to about 28%, or about 15% to about 34% in moles, based on the total number of moles of monomer units in the copolymer in the binder composition.

[0133] In some embodiments, the proportion of 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%, 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% in moles, based on the total number 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 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%, more than 29%, more than 30%, more than 31%, more than 32%, or more than 33% in moles, based on the total number of monomer units in the copolymer in the binder composition.

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

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

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

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

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

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

[0140] In some embodiments, structural units (a) and (b) are configured as the hydrophilic portion of the copolymer. In some embodiments, structural unit (c) is configured as the hydrophobic portion of the copolymer.

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

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

[0143] The addition of ester group-containing monomers in the preparation of the binder compositions disclosed herein has been found to result in the 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.

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

[0145] 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.

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

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

[0148] In some embodiments, the viscosity of the binder composition is from about 10,000 mPa·s to about 50,000 mPa·s, from about 10,000 mPa·s to about 47,500 mPa·s, from about 10,000 mPa·s to about 45,000 mPa·s, from about 10,000 mPa·s to about 42,500 mPa·s, from about 10,000 mPa·s to about 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, from about 15,000 mPa·s to about 35,000 mPa·s.

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

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

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

[0152] In some embodiments, the weight average molecular weight of the binder composition is about 50,000 g / mol to about 200,000 g / mol, about 55,000 g / mol to about 200,000 g / mol, about 60,000 g / mol to about 200,000 g / mol, about 65,000 g / mol to about 200,000 g / mol, about 70,000 g / mol to about 200,000 g / mol, about 75,000 g / mol to about 200,000 g / mol, about 80,000 g / mol to about 200,000 g / mol, about 85,000 g / mol to about 200,000 g / mol, about 90,000 g / mol to about 200,000 g / mol, about 90,000 g / mol to about 190,000 g / mol, about 90,000 g / mol to about 180,000 g / mol, about 90,000 g / mol to about 170,000 g / mol, about 90,000 g / mol to about 160,000 g / mol, about 95,000 g / mol to about 160,000 g / mol, about 100,000 g / mol to about 160,000 g / mol, about 100,000 g / mol to about 155,000 g / mol, about 100,000 g / mol to about 15 0 ,000 g / mol, about 100,000 g / mol to about 145,000 g / mol, or about 100,000 g / mol to about 140,000 g / mol. When the weight average molecular weight of the binder composition is not more than the 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 above-defined lower limit value, 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.

[0153] In some embodiments, the weight average molecular weight of the binder composition is less than 200,000 g / mol, less than 195,000 g / mol, less than 190,000 g / mol, less than 185,000 g / mol, less than 180,000 g / mol, less than 175,000 g / mol, less than 170,000 g / mol, less than 165,000 g / mol, less than 160,000 g / mol, less than 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, less than 105,000 g / mol, less than 100,000 g / mol, less than 95,000 g / mol, less than 90,000 g / mol, less than 85,000 g / mol, less than 80,000 g / mol, less than 75,000 g / mol, less than 70,000 g / mol, less than 65,000 g / mol, or less than 60,000 g / mol. In some embodiments, the weight average molecular weight of the binder composition is 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, more than 95,000 g / mol, more than 10,000 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.

[0154] In some embodiments, the number average molecular weight of the binder composition is from about 10,000 g / mol to about 100,000 g / mol, from about 15,000 g / mol to about 100,000 g / mol, from about 20,000 g / mol to about 100,000 g / mol, from about 25,000 g / mol to about 100,000 g / mol, from about 30,000 g / mol to about 100,000 g / mol, from about 35,000 g / mol to about 100,000 g / mol, from about 40,000 g / mol to about 100,000 g / mol, 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.

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

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

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

[0158] The binder composition of the present invention exhibits 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 in the production of battery electrodes, preventing separation, and improving the mechanical stability of the electrodes. In some embodiments, the adhesive strength between the binder composition and the current collector is from about 2 N / cm to about 4 N / cm, from about 2.1 N / cm to about 4 N / cm, from about 2.2 N / cm to about 4 N / cm, from about 2.3 N / cm to about 4 N / cm, from about 2.4 N / cm to about 4 N / cm, from about 2.5 N / cm to about 4 N / cm, from about 2.6 N / cm to about 4 N / cm, from about 2.7 N / cm to about 4 N / cm, from about 2.8 N / cm to about 4 N / cm, from about 2.9 N / cm to about 4 N / cm, from about 3 N / cm to about 4 N / cm, from about 2 N / cm to about 3.9 N / cm, from about 2 N / cm to about 3.8 N / cm, from about 2 N / cm to about 3.7 N / cm, from about 2 N / cm to about 3.6 N / cm, from about 2 N / cm to about 3.5 N / cm, from about 2 N / cm to about 3.4 N / cm, from about 2 N / cm to about 3.3 N / cm, from about 2 N / cm to about 3.2 N / cm, from about 2 N / cm to about 3.1 N / cm, from about 2 N / cm to about 3 N / cm, from about 2.5 N / cm to about 3.5 N / cm, from about 2.3 N / cm to about 3.7 N / cm, from about 2.5 N / cm to about 3 N / cm or from about 3 N / cm to about 3.5 N / cm.

[0159] 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.

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

[0161] In some embodiments, the electrode active material is a cathode active material, and the cathode active material is 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 is 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.

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

[0163] In some embodiments, the cathode active material is LiNi 0.33 Mn 0.33 Co 0.33 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.

[0164] 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.

[0165] 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.

[0166] 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.

[0167] 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.

[0168] 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 volume or weight ratio of the core to the shell is 95:5, 90:10, 80:20, 70:30, 60:40, 50:50, 40:60, or 30:70.

[0169] The current collector acts 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 includes a conductive material, and the inner layer includes 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 include a conductive material, and the intermediate layer includes an insulating material or another conductive material, for example, a plastic substrate coated with a metal film 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, polyphenyl 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 includes a carbon-containing material. In some embodiments, the current collector is not coated with a protective coating.

[0170] The thickness of the current collector affects the volume it occupies 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.

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

[0172] 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 nanoplatelets, carbon fibers, carbon nanofibers, graphitized carbon flakes, carbon nanotubes, activated carbon, Super P, 0-dimensional KS6, 1-dimensional vapor-grown carbon fiber (VGCF), mesoporous carbon, and combinations thereof.

[0173] Also, the cathode fabricated using the binder composition in the present invention exhibits strong adhesion between the electrode layer and the current collector. The fact that the electrode layer has 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.

[0174] 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.

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

[0176] The degree of swelling of the binder composition due to electrolyte uptake in a secondary battery provides insights into the crystallinity of the binder composition, the way the binder composition interacts with the electrolyte, and the flexibility of the binder composition. 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 that are 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 and ensure good ion transport without the binder composition decomposing when it swells. The semi-crystalline binder composition disclosed herein benefits from both influencing factors and thus exhibits excellent electrochemical performance.

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

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

[0179] The method disclosed herein can use an aqueous solvent in the manufacturing process, so it can save processing time and equipment, and there is no need to handle or recycle dangerous organic solvents, which has the advantage of improving safety. In addition, since the entire process is simplified, the cost is reduced. Therefore, this method is particularly suitable for industrial processes because it is low-cost and easy to handle.

[0180] The following examples are presented to illustrate embodiments of the present invention, but are not intended to limit the present invention to the specific embodiments defined. Unless otherwise indicated, all parts and percentages are by weight. All numerical values are approximate. When a numerical range is given, it should be understood that embodiments outside the described range 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

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

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

[0183] The adhesion strength of the dried binder composition layer was measured with a tensile testing machine (DZ-106A, Dongguan Zonghao 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 a humidity of 50% to 60% 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 sandwiched 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 maximum measured peeling force was taken as the adhesion strength. The measurement was repeated 3 times and the average value was determined.

[0184] 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 in 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 containing the electrolyte, the electrolyte on the strip surface was absorbed with absorbent paper. The weight of the immersed binder composition strips was measured. The ratio of the weight change of the strips before and after immersion in the electrolyte to the weight of the strips before immersion in the electrolyte was taken as the electrolyte swelling. The measurement was repeated 3 times and the average value was determined.

[0185] The solid content of the binder composition is measured by the degree of mass change of the binder composition before and after drying. Approximately 1 g of the binder composition was weighed into a weighing bottle and dried at 110 ± 5 °C and -0.09 MPa for more than 5 hours using a vacuum dryer. After cooling this binder composition in a desiccator for about 15 minutes, the 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.

[0186]

Equation

[0187] The weight-average molecular weight and number-average molecular weight of the binder composition were measured by gel permeation chromatography (GPC). First, the binder composition was dissolved in dimethylformamide at room temperature. When the dissolution of the binder composition was complete, 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 values in terms of the standard substance. 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.

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

[0189] Eluent: Dimethylformamide

[0190] Flow rate: 1 ml / min

[0191] Sample weight: 2 mg

[0192] Detector: Waters2414 refractive index (RI) detector

[0193] Detection temperature: 35 °C

[0194] Standard substance: Polystyrene Example 1 A) Preparation of Binder Composition

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

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

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

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

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

[0200] After the reaction was completed, the temperature of the fifth suspension was lowered to 25°C. 19.12 g of NaOH was dissolved in 3300 g of pure water. Then, 3319.12 g of sodium hydroxide solution was added dropwise to the fifth suspension over 1 hour to adjust the pH to 7.59, forming the sixth suspension. Filtration was carried out using a 200-mesh filter paper to prepare the binder composition. The solid content of the binder composition was 6.77 wt.%. The weight-average molecular weight of the binder composition was 125,031 g / mol, the number-average molecular weight was 55,437 g / mol, and the polydispersity index was 2.26. 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 Positive Electrode

[0201] 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 6.77 wt.%) were dispersed in deionized water to prepare a first mixture. After addition, the first mixture was further stirred at 25°C and a rotational speed of 1200 rpm for about 30 minutes.

[0202] Then, 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. Then, the second mixture was further stirred at 25°C for about 60 minutes at a rotational speed of 1200 rpm to form a homogenized slurry.

[0203] This homogenized slurry was applied to one side of an aluminum foil with a thickness of 14 μm as a current collector using a doctor blade coater. The slurry film applied 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 / cm2 It was C) Preparation of Negative Electrode

[0204] 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 (AL-2001, Japan A&L Co., Ltd., Japan) as a binder, 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

[0205] 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.

[0206] Next, an electrolyte was injected into the case holding the filled electrode under a high-purity argon atmosphere with a moisture content and an oxygen content of 3 ppm or less respectively. The electrolyte was LiPF 6(1M) was a solution prepared by mixing ethylene carbonate (EC), ethyl methyl carbonate (EMC), and dimethyl carbonate (DMC) in a volume ratio of 1:1:1. After filling the electrolyte, the coin cell was vacuum-sealed and mechanically pressed using a standard circular punch die. E) Electrochemical Measurement

[0207] A multi-channel battery tester (BTS-4008-5V10mA, obtained from Neware Electronics Co., Ltd, China) was used to analyze the coin cell in constant current mode. After one cycle at C / 20, charge and discharge were carried out at a rate of C / 2. Charge-discharge cycle tests of the cell were performed under the conditions of 3.0 - 4.3V, current density C / 2, and 25°C to determine the discharge capacity. The electrochemical performance of the coin cell of Example 1 was measured and shown in Table 2 below. Preparation of Binder Composition of Example 2

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

[0235] In the preparation of the second suspension, 34.0 g of AA was added. In the preparation of the third suspension, 14.96 g of AM was added. In the preparation of the fourth suspension, 19.04 g of AN was added. An inducer composition was prepared in the same manner as in Example 2 except for the above. Fabrication of the positive electrodes of Examples 2 to 11, 15 to 16 and Comparative Examples 1 to 10

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

[0237] The positive electrode of Example 12 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). Fabrication of the positive electrode of Example 13

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

[0239] The positive electrode of Example 14 was fabricated 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). Fabrication of the negative electrodes of Examples 2 to 16 and Comparative Examples 1 to 10

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

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

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

[0243] 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. 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 [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 ratio of the structural unit (a) derived from the carboxylic acid group-containing monomer in the copolymer is about 33% to about 70% in moles, based on the total number of moles 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 ratio of the structural unit (b) derived from the amide group-containing monomer in the copolymer is about 10% to about 35% 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, and is 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 10% to about 30% in terms of mole, based on the total number of moles of monomer units in the copolymer in the binder composition, and is the binder composition according to [1]. [8] The dispersion medium is water, and is the binder composition according to [1]. [9] The binder composition according to claim 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 (c) derived from the nitrile group-containing monomer in the copolymer is about 65% to about 90% in terms of mole, based on the total number of moles of monomer units in the copolymer of the binder composition, and is the binder composition according to [1].

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

[12] The binder composition according to [1], wherein the total molar ratio 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 to the structural unit (c) derived from the nitrile group-containing monomer in the copolymer is from about 1 to about 7.

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

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

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

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

[17] The binder composition according to [1], wherein the solid content of the binder composition is about 5% to about 10% by weight based on the total weight of the binder composition.

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

[19] The electrode for a secondary battery according to

[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 33% to 70% in terms of mol based on the total number of moles of the 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 10% to 35% in terms of mol based on the total number of moles of the 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 10% to 30% in terms of mol based on the total number of moles of the 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 secondary battery is a lithium ion battery, and the binder composition according to Claim 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-dimethylaminopropylmethacrylamide, N,N-dimethylaminoethylmethacrylamide, N,N-dimethylolmethacrylamide, diacetonemethacrylamide, methacryloylmorpholine, and combinations thereof, and the binder composition according to Claim 1.

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 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. The binder composition according to claim 6.

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

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

10. The molar ratio of 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 to the structural unit (c) derived from the nitrile group-containing monomer in the copolymer is 1 to 7. 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 7% to 10%. The binder composition according to claim 1.

14. The solid content of the binder composition is 5% to 10% 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 33% to 70% in 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 10% to 35% in 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 10% to 30% in 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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