Binder composition for secondary battery

Abstract

An aqueous binder composition for a secondary battery electrode includes a copolymer and a dispersion medium, wherein the copolymer includes structural unit (a), structural unit (b), and structural unit (c). The binder composition disclosed herein has improved binding ability. Furthermore, a battery including an electrode prepared using the binder composition disclosed herein exhibits excellent electrochemical performance.

Description

Technical Field

[0001] This invention relates to the field of batteries. Specifically, this invention relates to binder compositions for lithium-ion batteries. Background Technology

[0002] Over the past few decades, lithium-ion batteries (LIBs) have been widely used in various applications, especially consumer electronics, due to their excellent energy density, long cycle life, and high discharge capacity. With the rapid development of the electric vehicle (EV) and grid energy storage markets, high-performance, low-cost LIBs currently offer one of the most promising options for large-scale energy storage devices.

[0003] Lithium-ion battery electrodes are typically manufactured by coating an organic-based slurry onto a metal current collector. This slurry contains electrode active materials, conductive carbon, and a binder in an organic solvent. The binder provides good electrochemical stability by binding the electrode components together and adhering them to the current collector. Polyvinylidene fluoride (PVDF) is one of the most commonly used binders in the commercial lithium-ion battery industry. However, PVDF is insoluble in water and can only dissolve in certain organic solvents, such as N-methyl-2-pyrrolidone (NMP), which is flammable and toxic, thus requiring special handling.

[0004] Due to the aforementioned risks, when using NMP, a recovery system must be installed during the drying process to recover NMP vapors. This incurs high costs in the manufacturing process because it requires a significant capital investment. Therefore, it is preferable to choose a cheaper and more environmentally friendly solvent, such as water, as it eliminates the substantial investment costs associated with a recovery system.

[0005] In view of these issues, attempts have been made to replace traditional PVDF with more environmentally friendly, water-soluble binder materials, or to take advantage of the known benefits of PVDF as an electrode slurry binder without using organic solvents that require specific recycling treatment during electrode manufacturing.

[0006] Known waterborne binders, such as carboxymethyl cellulose (CMC) and styrene-butadiene rubber (SBR), exhibit only limited bonding ability and poor cycle life. In particular, SBR requires thickeners to adjust the binder viscosity. Furthermore, SBR exhibits high expandability and poor agglomeration, leading to uneven dispersion in the electrode slurry, high electrode resistance, and poor electrode performance. Moreover, within the battery, the cathode is subjected to high voltage, but most rubbers (including SBR) are only stable at low voltages at the anode and decompose at high voltages. Therefore, their application is somewhat limited, especially within the cathode.

[0007] European patent application publication number EP2555293B1 discloses an aqueous electrode slurry for lithium-ion electrochemical batteries. The slurry comprises an electrochemically active material in an aqueous solution, and a combination of at least one of PVDF, SBR, and polyacrylic acid (PAA) and CMC. This prior art attempts to combine PVDF with an aqueous slurry to achieve easier handling, reduced environmental pollution, and lower costs, while retaining the known chemical and electrochemical advantages of PVDF as a binder. These advantages include electrochemical stability, lifetime stability, and a relatively low required binder dosage, thus allowing for higher rate capability. While the slurry disclosed in this prior art does not contain organic solvents, it still contains a fluorinated binder. PVDF is highly fluorinated and decomposes into toxic substances when heated, posing risks to human health and the environment.

[0008] In light of the above, there is always a need for aqueous binder compositions for secondary batteries that possess excellent adhesion and high electrochemical stability, and can maintain their properties during the preparation of the cathode slurry, thereby enabling the binder compositions to contribute to the excellent electrochemical performance of the battery. Summary of the Invention

[0009] The aforementioned needs are met through the various aspects and embodiments disclosed herein. This document provides a binder composition for a secondary battery electrode, comprising a copolymer and a dispersion medium, wherein the copolymer comprises structural units (a), (b), and (c). This binder composition exhibits improved adhesion. Furthermore, batteries comprising cathodes prepared using the binder composition disclosed herein exhibit excellent electrochemical performance. Attached Figure Description

[0010] Figure 1 This is a flowchart illustrating one embodiment of the steps for preparing the adhesive composition. Detailed Implementation

[0011] This document provides a binder composition for a secondary battery electrode, comprising a copolymer and a dispersion medium, wherein the copolymer comprises structural units (a), (b), and (c).

[0012] The term "electrode" refers to either "cathode" or "anode".

[0013] The terms "positive electrode" and "cathode" are used interchangeably. Similarly, the terms "negative electrode" and "anode" are used interchangeably.

[0014] The terms “binder,” “binder material,” or “binder composition” refer to a chemical compound, mixture of compounds, or polymer that forms a colloidal solution or colloidal dispersion in a dispersion medium and is used to fix electrode active materials and / or conductive agents in a suitable position and adhere them to conductive metal parts to form an electrode.

[0015] The term "conductive agent" refers to a material with good electrical conductivity. Therefore, conductive agents are typically mixed with electrode active materials during electrode formation to improve the electrode's conductivity. In some embodiments, the conductive agent is chemically active. In some embodiments, the conductive agent is chemically inert.

[0016] The term "polymer" refers to a polymeric compound prepared by polymerizing the same or different types of monomers. The general term "polymer" includes the terms "homopolymer" and "copolymer".

[0017] The term "homogeneous polymer" 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] The term "unsaturated" refers to a moiety that has one or more unsaturated units.

[0020] The term "alkyl" or "alkyl group" refers to a group having the general formula C n H 2n+1 The alkyl group is a monovalent group derived from a saturated, unbranched, or branched aliphatic hydrocarbon by removing one hydrogen atom, where n is an integer. Examples of alkyl groups include, but are not limited to, C1-C8 alkyl groups, such as methyl, ethyl, propyl, isopropyl, 2-methyl-1-propyl, 2-methyl-2-propyl, 2-methyl-1-butyl, 3-methyl-1-butyl, 2-methyl-3-butyl, 2,2-dimethyl-1-propyl, 2-methyl-1-pentyl, 3-methyl-1-pentyl, 4-methyl-1-pentyl, 2-methyl-2-pentyl, 3-methyl-2-pentyl, 4-methyl-2-pentyl, 2,2-dimethyl-1-butyl, 3,3-dimethyl-1-butyl, 2-ethyl-1-butyl, butyl, isobutyl, tert-butyl, pentyl, isopentyl, neopentyl, hexyl, heptyl, and octyl. Longer alkyl groups include nonyl and decyl groups. The alkyl group may be unsubstituted or substituted with one or more suitable substituents.

[0021] The term "cycloalkyl" or "cycloalkyl group" refers to a saturated or unsaturated cyclic non-aromatic hydrocarbon group having a monocyclic or multiple fused rings. Examples of cycloalkyl groups include, but are not limited to, C3-C7 cycloalkyl groups, such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, and cycloheptyl; C3-C7 cycloalkenyl groups, such as cyclopropenyl, cyclobutenyl, cyclopentenyl, cyclohexenyl, and cycloheptenyl; and cyclic terpenes and bicyclic terpenes. The cycloalkyl group may be unsubstituted or substituted with one or two suitable substituents.

[0022] The term "alkoxy" refers to an alkyl group as defined above, connected to the main carbon chain via an oxygen atom. Some non-limiting examples of alkoxy groups include methoxy, ethoxy, propoxy, butoxy, etc. Furthermore, the alkoxy group defined above can be substituted or unsubstituted, wherein the substituent can be, but is not limited to, deuterium, hydroxyl, amino, halogen, cyano, alkoxy, alkyl, alkenyl, alkynyl, mercapto, nitro, etc.

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

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

[0025] The term "aliphatic" refers to alkyl, alkenyl, ynyl, alkylene, alkenyl, or ynylene groups.

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

[0027] The term "substituted" used to describe a compound or chemical moiety means that at least one hydrogen atom of that compound or chemical moiety is replaced by a second chemical moiety. This second chemical moiety is called a "substituent". Examples of substituents include, but are not limited to, halogens; alkyl groups; heteroalkyl groups; alkenyl groups; alkynyl groups; heteroaryl groups; hydroxyl groups; alkoxy groups; amino groups; nitro groups; mercapto groups; thioether groups; imino groups; cyano groups; amide groups; phosphonates; hypophosphonates; carboxyl groups; thiocarbonyl groups; sulfonyl groups; sulfonamide groups; acyl groups; formyl groups; acyloxy groups; alkoxycarbonyl groups; carbonyl groups; and haloalkyl groups (e.g., trifluoroalkyl groups). Methyl; carbocyclic cycloalkyl, which can be monocyclic or fused or unfused polycyclic (e.g., cyclopropyl, cyclobutyl, cyclopentyl, or cyclohexyl), or heterocyclic alkyl, which can be monocyclic or fused or unfused polycyclic (e.g., pyrrolidinyl, piperidinyl, piperazinyl, morpholinyl, or thiazinyl); carbocyclic or heterocyclic, monocyclic or fused or unfused polycyclic aryl (e.g., phenyl, naphthyl, pyrrolidinyl, indolyl, furanyl, thiophenyl). iophenyl), imidazole, oxazolyl, isoxazolyl, thiazolyl, triazolyl, tetrazolyl, pyrazolyl, pyridinyl, quinolinyl, isoquinolinyl, acridineyl, pyrazinyl, pyridazinyl, pyrimidinyl, benzimidazolyl, benzothiophene, or benzofuranyl); amino (primary, secondary, or tertiary amine); ortho-lower alkyl; ortho-aryl, aryl; aryl-lower alkyl; -CO2CH3; -CONH2; -OCH2CONH2; -NH2; -SO2NH2; -OCHF2; -CF3; -OCF3; -NH(alkyl); -N(alkyl)2; -NH(aryl); -N(alkyl)(aryl); -N(aryl)2; -CHO; -CO(alkyl); -CO(aryl); -CO2(alkyl); and -CO2(aryl); and these groups may optionally be substituted with fused ring structures or bridged structures (e.g., -OCH2O-). These substituents may optionally be further substituted with substituents selected from these groups. Unless otherwise specified, all chemical groups disclosed herein may be substituted.

[0028] The term "halogen" or "halogenated" refers to F, Cl, Br, or I.

[0029] The abbreviation "(methyl)propylene" includes both "propylene" and "methylpropylene".

[0030] The term "monomer unit" refers to the building block of a polymer provided by a single monomer.

[0031] The term "structural unit" refers to a total monomer unit provided by the same monomer type in a polymer.

[0032] The term "apply" refers to the action 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 capable of conducting current to the electrode during the 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 covered with a conductive coating (e.g., a carbon black-based coating). The conductive metal layer or substrate may be in the form of a foil or a porous body with a three-dimensional network structure, and may be a polymer or a metallic material or a metallized polymer. In some embodiments, the three-dimensional porous current collector is covered with a conformal carbon layer.

[0034] The term "electrode layer" refers to a layer that is in contact with the current collector and contains electrochemically active material. In some embodiments, the electrode layer is formed by applying a coating to the current collector. In some embodiments, the electrode layer is located on the surface of the current collector. In other embodiments, a three-dimensional porous current collector is covered with a conformal electrode layer.

[0035] The term "room temperature" refers to an indoor temperature of approximately 18°C ​​to approximately 30°C, such as 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 approximately 20°C + / - 1°C, + / - 2°C, or + / - 3°C. In other embodiments, room temperature refers to a temperature of approximately 22°C or approximately 25°C.

[0036] The term "particle size D50" refers to the volume-based cumulative 50% size (D50), which is the particle size at the 50% point on the cumulative curve when the cumulative curve is plotted through a volume-based particle size distribution and the total volume is 100% (i.e., the particle diameter at the 50th percentile (median) of the particle volume). Further, regarding the cathode active material of the present invention, particle size D50 refers to the volume-average particle size of secondary particles formed by the mutual aggregation of primary particles; when the particles consist only of primary particles, particle size D50 refers to the volume-average particle size of the primary particles.

[0037] The term "polydispersity index" (PDI) refers to the weight-average molecular weight (M). w ) relative to number average molecular weight (M n The ratio of ) is a measure of the molecular weight distribution in a given adhesive composition sample.

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

[0039] The term "average roughness depth" (R) z ) refers to the arithmetic mean of the individual roughness depths over the 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 electrode active material coatings that are bonded together. It is a measure of the adhesion strength between the two materials and is typically expressed in N / cm.

[0041] The term "adhesion strength" refers to the magnitude of the force required to separate a current collector and an adhesive composition coating that are bonded together. It is a measure of the adhesive strength between the two materials and is typically expressed in N / cm.

[0042] The term "swelling" refers to the volume evolution of a binder composition after immersion in or absorption of an electrolyte due to electrolyte-binder interactions.

[0043] The term "C-rate" refers to the charging or discharging rate of a battery, expressed in ampere-hours (Ah) or milliampere-hours (mAh), based on its total storage capacity. For example, a 1C rate means utilizing all the stored energy in one hour; 0.1C means utilizing 10% of the energy in one hour or all the energy in 10 hours; and 5C means utilizing all the energy in 12 minutes.

[0044] The term "ampere-hour (Ah)" refers to the unit used to describe the storage capacity of a battery. For example, a 1Ah battery can provide 1 ampere of current for one hour or 0.5 amperes of current for two hours. Therefore, 1 ampere-hour (Ah) is equivalent to 3,600 coulombs of charge. Similarly, the term "milliampere-hour (mAh)" also refers to the unit used to describe the storage capacity of a battery and is 1,000th the capacity of an ampere-hour.

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

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

[0047] In the following description, all numerical values ​​disclosed herein are approximations, regardless of whether the terms "about" or "approximately" are used in conjunction. They may vary by 1%, 2%, 5%, or sometimes 10% to 20%. Whenever a lower bound R is disclosed... L and upper limit R U When the numerical range is specified, any value within that range is specifically disclosed. Specifically, the following values ​​within that range are specifically disclosed: R = R L +k*(R U -R L), where k is a variable from 0% to 100%. Furthermore, any numerical range defined by the two R values ​​determined in the above manner is also specifically disclosed.

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

[0049] Because binders are considered electrochemically inert materials, their impact on battery performance is often underestimated. The purpose of binders is to adhere active material particles and conductive agents together to form a continuous conductive path to the current collector. In addition to bonding ability, binder materials should also be able to promote electron and ion transport to reduce the impedance between the current collector and electrode materials, and possess sufficient elasticity to prevent the electrodes from swelling due to the volume expansion and contraction of the electrode active materials during charging and discharging.

[0050] Polyvinylidene fluoride (PVDF) has been widely used as a binder material in the production of lithium-ion batteries. However, PVDF can only be dissolved in specific organic solvents such as NMP, which, as mentioned above, are hazardous and require a recovery system to recover the vapors released during the drying process. This results in significant energy consumption and production costs during manufacturing. Therefore, exploring new environmentally friendly binder materials to replace PVDF has become a top priority in the development of lithium-ion battery binder materials.

[0051] Carboxymethyl cellulose (CMC) and styrene-butadiene rubber (SBR) are some typical water-based binders already used in large-scale commercial applications. However, these binders have limited bond strength and cannot effectively prevent electrode swelling. Furthermore, within the battery, the cathode is subjected to high voltage, but most rubbers (including SBR) are only stable at low voltages at the anode and decompose at high voltages. Therefore, the application of these binders, especially within the cathode, is somewhat limited.

[0052] Therefore, the present invention provides an aqueous binder composition comprising a copolymer and a dispersion medium, wherein the copolymer comprises structural units (a), (b), and (c), and an electrode comprising said binder composition. It is evident that the binder composition described herein exhibits enhanced adhesion and flexibility, and simultaneously possesses the unexpected effect of improving the capacity and electrochemical performance of the cathode formed therefrom.

[0053] Figure 1This is a flowchart illustrating the steps of a method 100 for preparing one embodiment of the adhesive composition disclosed herein. In some embodiments, the adhesive composition described herein is prepared by polymerization of a monomer, polymer, or monomer-polymer complex dispersed in an aqueous phase, wherein the polymerization is initiated by free radicals generated by a water-soluble free radical initiator.

[0054] In some embodiments, in step 101, a first neutralizing solution is added to the dispersion medium to form a first suspension. In some embodiments, the first neutralizing solution is prepared by dissolving a first neutralizing agent in water. Adding this neutralizing solution helps improve the stability of the polymerization reaction and provides a pH range within which an initiator, which will be added in subsequent stages, can generate free radicals.

[0055] Establishing an ideal pH range is particularly important in aqueous systems, and neutralizing agents are commonly used to adjust the pH. 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 serves as a solvent for neutralizing agents and other substances (such as free radical initiators) to be added in subsequent steps. In some embodiments, the adhesive compositions disclosed herein are prepared using an aqueous treatment method, i.e., the dispersion medium is water.

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

[0058] In some embodiments, the second suspension is formed by adding the monomer derived into structural unit (a) to the first suspension in step 102. In other embodiments, the second suspension is formed by adding a solution containing the monomer derived into structural unit (a) to the first suspension. The solution containing the monomer derived into structural unit (a) can be prepared by dissolving the monomer in water.

[0059] Structural unit (a) is derived from a monomer containing an acid group. In some embodiments, the acid group is selected from the group consisting of carboxylic acids, sulfonic acids, sulfuric acids, phosphonic acids, phosphoric acids, nitric acids, and combinations thereof. The acids listed above also include their salts and derivatives.

[0060] In some embodiments, the carboxylic acid is acrylic acid, methacrylic acid, crotonic acid, 2-butylcrotonic acid, cinnamic acid, maleic acid, maleic anhydride, fumaric acid, itaconic acid, itaconic anhydride, 4,4-dimethylitaconic acid, or a combination thereof. In some embodiments, the carboxylic acid is 2-ethylacrylic acid, isocrotonic acid, cis-2-pentenoic acid, trans-2-pentenoic acid, angelic acid, or tiglic acid. (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-octenic acid, cis-2-octenic acid, trans-2-decenoic acid, α-acetoxyacrylic acid, β-trans-aryloxyacrylic acid, α-chloro-β-E-methoxyacrylic acid, or combinations thereof.

[0061] In some embodiments, the carboxylic acid is methylmaleic acid, dimethylmaleic acid, phenylmaleic acid, bromomaleic acid, chloromaleic acid, dichloromaleic acid, fluoromaleic acid, difluoromaleic acid, nonyl hydrogenmaleate, decyl hydrogen maleate, dodecyl hydrogen maleate, octadecyl hydrogen maleate, fluoroalkyl hydrogen maleate, or a combination thereof. In some embodiments, the carboxylic acid is maleic anhydride, methylmaleic anhydride, dimethylmaleic anhydride, acrylic anhydride, methacrylic anhydride, methacrolein, methacryloyl chloride, methacryloyl fluoride, methacryloyl bromide, or a combination thereof.

[0062] In some embodiments, the sulfonic acid is vinyl sulfonic acid, methyl vinyl sulfonic acid, allyl vinyl sulfonic acid, allyl sulfonic acid, methyl allyl sulfonic acid, styrene sulfonic acid, 2-sulfoethyl methacrylate, 2-methyl-2-propen-1-sulfonic acid, 2-acrylamido-2-methyl-1-propane sulfonic acid, 3-allyloxy-2-hydroxy-1-propane sulfonic acid, or a combination thereof.

[0063] In some embodiments, the sulfuric acid is allyl hydrogen sulfate, ethylene hydrogen sulfate, 4-allylphenol sulfate, or a combination thereof.

[0064] In some embodiments, the phosphonic acid is vinylphosphonic acid, allylphosphonic acid, vinylbenzylphosphonic acid, acrylamide alkylphosphonic acid, methacrylamide alkylphosphonic acid, acrylamide alkyl diphosphonic acid, acryloylphosphonic acid, 2-methacryloyloxyethylphosphonic acid, bis(2-methacryloyloxyethyl)phosphonic acid, ethylene 2-methacryloyloxyethylphosphonic acid, ethyl-methacryloyloxyethylphosphonic acid, or a combination thereof.

[0065] In some embodiments, the phosphoric acid is mono(2-acryloyloxyethyl) phosphate, mono(2-methacryloyloxyethyl) phosphate, diphenyl(2-acryloyloxyethyl) phosphate, diphenyl(2-methacryloyloxyethyl) phosphate, phenyl(2-acryloyloxyethyl) phosphate, phosphoroyloxyethyl methacrylate, 3-chloro-2-phosphoroyloxypropyl methacrylate, phosphoroyloxypoly(ethylene glycol) monomethacrylate, phosphoroyloxypoly(propylene glycol) methacrylate, or (meth)acryloyloxyethyl phosphate. Ester, (meth)acryloyloxypropyl phosphate, (meth)acryloyloxy-2-hydroxypropyl phosphate, (meth)acryloyloxy-3-hydroxypropyl phosphate, (meth)acryloyloxy-3-chloro-2-hydroxypropyl phosphate, allyl hydrogen phosphate, vinyl hydrogen phosphate, allyl hydrogen pyrophosphate, vinyl hydrogen pyrophosphate, allyl tripolyphosphate, vinyl tripolyphosphate, allyl tetrapolyphosphate, allyl trimetaphosphate, vinyl trimetaphosphate, isopentenyl phosphate, isopentenyl pyrophosphate, or combinations thereof.

[0066] In some embodiments, the nitric acid is allyl hydrogen nitrate, vinyl hydrogen nitrate, or a combination thereof.

[0067] In some embodiments, based on the total weight of the monomers added in the preparation of the binder composition, the percentage of monomers deriving into structural unit (a) is, by weight, about 17% to about 57%, about 17% to about 55%, about 17% to about 53%, about 17% to about 50%, about 17% to about 47%, about 17% to about 45%, about 17% to about 43%, about 17% to about 40%, about 17% to about 37%, and about 17%. About 35%, about 17% to about 33%, about 17% to about 30%, about 20% to about 57%, about 20% to about 55%, about 20% to about 53%, about 20% to about 50%, about 20% to about 47%, about 20% to about 45%, about 20% to about 43%, about 20% to about 40%, about 20% to about 37%, about 20% to about 35%, about 20% to about 33%, about 20% to about 30%, about 25% % to 57%, about 25% to 55%, about 25% to 53%, about 25% to 50%, about 25% to 47%, about 25% to 45%, about 25% to 43%, about 25% to 40%, about 25% to 37%, about 25% to 35%, about 30% to 57%, about 30% to 55%, about 30% to 53%, about 30% to 50%, about 30% to 47%, about 30% to about 45%, about 30% to about 43%, about 30% to about 40%, about 35% to about 57%, about 35% to about 55%, about 35% to about 53%, about 35% to about 50%, about 35% to about 47%, about 35% to about 45%, about 40% to about 57%, about 40% to about 55%, about 40% to about 53%, about 40% to about 50%, about 45% to about 57%, or about 45% to about 55%.

[0068] In some embodiments, based on the total weight of monomers added in the preparation of the adhesive composition, the percentage of monomers deriving structural unit (a) is less than 57%, less than 55%, less than 53%, less than 50%, less than 47%, less than 45%, less than 43%, less than 40%, less than 37%, less than 35%, less than 33%, less than 30%, less than 27%, less than 25%, less than 23%, or less than 20% by weight. In some embodiments, based on the total weight of monomers added in the preparation of the adhesive composition, the percentage of monomers deriving structural unit (a) is more than 17%, more than 20%, more than 23%, more than 25%, more than 27%, more than 30%, more than 33%, more than 35%, more than 37%, more than 40%, more than 43%, more than 45%, more than 47%, more than 50%, more than 53%, or more than 55% by weight.

[0069] In some embodiments, the stirring time of the first suspension and the second suspension is independently 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, the stirring time of the first suspension and the second suspension is independently 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 stirring time of the first suspension and the second suspension is independently more than 5 minutes, more than 10 minutes, more than 15 minutes, more than 20 minutes, more than 25 minutes, more than 30 minutes, more than 35 minutes, or more than 40 minutes.

[0070] In some embodiments, the stirring speed of the first suspension and the second suspension is independently 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 100 rpm. In some embodiments, the stirring speed of the first suspension and the second suspension is independently 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 stirring speed of the first suspension and the second suspension is independently 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.

[0071] In some embodiments, the temperature of the second suspension is about 20°C to about 30°C, about 20°C to about 29°C, about 20°C to about 28°C, about 20°C to about 27°C, about 20°C to about 26°C, about 20°C to about 25°C, about 21°C to about 30°C, about 22°C to about 30°C, about 23°C to about 30°C, about 24°C to about 30°C, about 25°C to about 30°C, about 22°C to about 26°C, or about 24°C to about 28°C. In some embodiments, the temperature of the second suspension is below 30°C, below 29°C, below 28°C, below 27°C, below 26°C, below 25°C, below 24°C, below 23°C, below 22°C, or below 21°C. In some embodiments, the temperature of the second suspension is above 20°C, above 21°C, above 22°C, above 23°C, above 24°C, above 25°C, above 26°C, above 27°C, above 28°C, or above 29°C.

[0072] In some embodiments, a third suspension is formed by adding the monomer derived into structural unit (b) to the second suspension in step 103. In other embodiments, a third suspension is formed by adding a solution containing the monomer derived into structural unit (b) to the second suspension. The solution containing the monomer derived into structural unit (b) can be prepared by dissolving the monomer in water.

[0073] Structural unit (b) is derived from monomers selected from groups consisting of monomers containing amide groups, monomers containing hydroxyl groups, and combinations thereof.

[0074] In some embodiments, the monomer containing the amide group 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-hydroxymethylmethacrylamide, N-(methoxymethyl)methacrylamide, N-(ethoxymethyl)methacrylamide, etc. N-(propoxymethyl)methacrylamide, N-(butoxymethyl)methacrylamide, N-(3-(dimethylamino)propyl)methacrylamide, N-(2-(dimethylamino)ethyl)methacrylamide, N,N-(dihydroxymethyl)methacrylamide, diacetone methacrylamide, diacetone acrylamide, methacryloylmorpholine, N-hydroxymethylacrylamide, N-methoxymethylacrylamide, N,N'-methylenebisacrylamide (MBA), N-hydroxymethylacrylamide or combinations thereof.

[0075] In some embodiments, the monomer containing a hydroxyl group is a monomer containing a hydroxyl group and containing C1 to C2. 20 Alkyl groups or C5 to C 20 Acrylates or methacrylates with cycloalkyl groups. In some embodiments, the monomer containing a hydroxyl group is 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 2-hydroxybutyl methacrylate, 3-hydroxypropyl acrylate, 3-hydroxypropyl methacrylate, 4-hydroxybutyl methacrylate, 5-hydroxypentyl acrylate, 6-hydroxyhexyl methacrylate, 1,4-cyclohexanediethanol mono(meth)acrylate, 3-chloro-2-hydroxypropyl methacrylate, diethylene glycol mono(meth)acrylate, allyl alcohol, or combinations thereof.

[0076] In some embodiments, based on the total weight of monomers added in the preparation of the binder composition, the percentage of monomers derived into structural unit (b) is, by weight, about 4% to about 30%, about 4% to about 29%, about 4% to about 28%, about 4% to about 27%, about 4% to about 26%, about 4% to about 25%, about 4% to about 24%, about 4% to about 23%, about 4% to about 22%, about 4% to about 21%, about 4% to about 20%, about 4% to about 19%, about 4% to about 18%, about 4% to about 17%, about 4% to about 16%, about 4% to about 15%, about 4% to about 14%, about 4% to about 13%, about 4% to about 12%, about 4% to about 11%, about 4% to about 10%. %, about 10% to about 30%, about 10% to about 29%, about 10% to about 28%, about 10% to about 27%, about 10% to about 26%, about 10% to about 25%, about 10% to about 24%, about 10% to about 23%, about 10% to about 22%, about 10% to about 21%, about 10% to about 20%, about 15% to about 30%, about 15% to about 29%, about 15% to about 28%, about 15% to about 27%, about 15% to about 26%, about 15% to about 25%, about 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%, or about 25% to about 30%.

[0077] In some embodiments, based on the total weight of monomers added in the preparation of the binder composition, the percentage of monomers derived into structural unit (b) 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%, or less than 5% by weight. In some embodiments, based on the total weight of monomers added in the preparation of the binder composition, the percentage of monomers deriving into structural unit (b) is more than 4%, more than 5%, more than 6%, more than 7%, more than 8%, more than 9%, more than 10%, more than 11%, more than 12%, more than 13%, more than 14%, more than 15%, more than 16%, more than 17%, more than 18%, more than 19%, more than 20%, more than 21%, more than 22%, more than 23%, more than 24%, more than 25%, more than 26%, more than 27%, more than 28%, or more than 29% by weight.

[0078] In some embodiments, the stirring time of the third suspension is 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 stirring time of the third suspension is 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 stirring time of the third suspension is more than 5 minutes, more than 10 minutes, more than 15 minutes, more than 20 minutes, more than 25 minutes, more than 30 minutes, more than 35 minutes, more than 40 minutes, more than 45 minutes, more than 50 minutes, or more than 55 minutes.

[0079] In some embodiments, the stirring speed of the third suspension is 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 stirring speed of the third suspension is 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 stirring speed of the third suspension is 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.

[0080] 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.

[0081] In some embodiments, the temperature of the third suspension is raised to below 70°C, below 68°C, below 65°C, below 62°C, below 60°C, below 58°C, below 55°C, below 52°C, below 50°C, below 48°C, below 45°C, below 42°C, below 40°C, below 38°C, or below 35°C. In some embodiments, the temperature of the third suspension is raised to above 30°C, above 32°C, above 35°C, above 38°C, above 40°C, above 42°C, above 45°C, above 48°C, above 50°C, above 52°C, above 55°C, above 58°C, above 60°C, above 62°C, or above 65°C.

[0082] In some embodiments, a fourth suspension is formed by adding the monomer derived into structural unit (c) to the third suspension in step 104. In other embodiments, a fourth suspension is formed by adding a solution containing the monomer derived into structural unit (c) to the third suspension. The solution containing the monomer derived into structural unit (c) can be prepared by dissolving the monomer in water.

[0083] Structural unit (c) is derived from monomers selected from the group consisting of monomers containing nitrile groups, monomers containing ether groups, monomers containing epoxy groups, monomers containing carbonyl groups, fluorine-containing monomers, and combinations thereof.

[0084] In some embodiments, the monomer containing a nitrile group includes α,β-olefinically unsaturated nitrile monomers. In some embodiments, the monomer containing a nitrile group is acrylonitrile, α-haloacrylonitrile, α-alkylacrylonitrile, or a combination thereof. In some embodiments, the monomer containing a nitrile group 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.

[0085] In some embodiments, the monomer containing the ether group is a vinyl ether, allyl ether, allyl vinyl ether, allyl glycidyl ether, 2H-hexafluoroisopropyl allyl ether, hydroxyl polyethoxy(10) allyl ether, allyl phenethyl ether, ethyl vinyl ether, propyl vinyl ether, n-butyl vinyl ether, or a combination thereof.

[0086] In some embodiments, the epoxy group-containing monomer is vinyl glycidyl ether, allyl glycidyl ether, allyl-2,3-epoxypropyl ether, butenyl glycidyl ether, butadiene monoepoxide, chloroprene monoepoxide, 3,4-epoxy-1-butene, 4,5-epoxy-2-pentene, 3,4-epoxy-1-vinylcyclohexane, 1,2-epoxy-4-vinylcyclohexane, 3,4-epoxycyclohexylethylene, epi-4-vinylcyclohexene, 1,2-epoxy-5,9-cyclododecadiene, or a combination thereof. In some embodiments, the epoxy group-containing monomer is 1,2-epoxy-5-hexene, 1,2-epoxy-9-decene, glycidyl acrylate, glycidyl methacrylate, glycidyl crotonate, 2,4-dimethylpentenoic acid glycidyl ester, 4-hexenoic acid glycidyl ester, 4-heptenoic acid glycidyl ester, 5-methyl-4-heptenoic acid glycidyl ester, sorbic acid glycidyl ester, linoleic acid glycidyl ester, oleic acid glycidyl ester, 3-butenoic acid glycidyl ester, 3-pentenoic acid glycidyl ester, 4-methyl-3-pentenoic acid glycidyl ester, or a combination thereof.

[0087] In some embodiments, the monomer containing the carbonyl group is methyl vinyl ketone, ethyl vinyl ketone, acrolein, acryloyl chloride, cinnamaldehyde, E-crotonaldehyde, 2-hexenal, 2-octenal, 2-methyl-2-pentenal, 4-methyl-3-penten-2-one, 1-octen-3-one, 2-pentyl-1-buten-3-one, or a combination thereof.

[0088] In some embodiments, the fluorinated monomer contains C1-C 20 The monomer is an alkyl group acrylate or methacrylate, or a combination thereof, wherein the monomer contains at least one fluorine atom. In some embodiments, the fluorinated monomer is a perfluoroalkyl acrylate, such as perfluorododecyl acrylate, perfluoron-octyl acrylate, perfluoron-butyl acrylate, perfluorohexylethyl acrylate, and perfluorooctylethyl acrylate; a perfluoroalkyl methacrylate, such as perfluorododecyl methacrylate, perfluoron-octyl methacrylate, perfluoron-butyl methacrylate, perfluorohexylethyl methacrylate, and perfluorooctylethyl methacrylate; a perfluorooxyalkyl acrylate, such as perfluorododecoxyethyl acrylate and perfluorodecoxyethyl acrylate; a perfluorooxyalkyl methacrylate, such as perfluorododecoxyethyl methacrylate and perfluorodecoxyethyl methacrylate, or a combination thereof. In some embodiments, the fluorinated monomer contains C1-C... 20A carboxylate salt containing an alkyl group and at least one fluorine atom, wherein the carboxylate salt is selected from the group consisting of crotonate, malate, fumarate, itaconic acid, or combinations thereof. In some embodiments, the fluorinated monomer is vinyl fluoride, trifluoroethylene, trifluorochloroethylene, fluoroalkyl vinyl ether, perfluoroalkyl vinyl ether, hexafluoropropylene, 2,3,3,3-tetrafluoropropylene, vinylidene fluoride, tetrafluoroethylene, 2-fluoroacrylate, or combinations thereof.

[0089] In some embodiments, based on the total weight of monomers added in the preparation of the binder composition, the percentage of monomers derived into structural unit (c) is approximately 38% to 58% by weight, approximately 38% to 57%, approximately 38% to 56%, approximately 38% to 55%, approximately 38% to 54%, approximately 38% to 53%, approximately 38% to 52%, approximately 38% to 51%, approximately 38% to 50%, approximately 38% to 49%, approximately 38% to 48%, approximately 40% to 58%, approximately 40% to 57%, approximately 40% to 56%, approximately 40% to 55%, approximately 40% to 54%, approximately 40% to 53%, approximately 40% to 52%, approximately 40% to 53%, approximately 40% to 52%, approximately 40% to 54%, approximately 40% to 53%, approximately 40% to 52%, approximately 40% to 53 ... % to 51%, about 40% to 50%, about 43% to 58%, about 43% to 57%, about 43% to 56%, about 43% to 55%, about 43% to 54%, about 43% to 53%, about 43% to 52%, about 43% to 51%, about 43% to 50%, about 45% to 58%, about 45% to 57%, about 45% to 56%, about 45% to 55%, about 45% to 54%, about 45% to 53%, about 45% to 52%, about 45% to 51%, about 45% to 50%, about 48% to 58%, about 48% to 57%, about 48% to 56%, or about 48% to 55%.

[0090] In some embodiments, based on the total weight of the monomers added in the preparation of the binder composition, the percentage of monomers derived into structural unit (c) is less than 58%, less than 57%, less than 56%, less than 55%, less than 54%, less than 53%, less than 52%, less than 51%, less than 50%, less than 49%, less than 48%, less than 47%, less than 46%, less than 45%, less than 44%, less than 43%, less than 42%, less than 41%, less than 40%, or less than 39% by weight. In some embodiments, based on the total weight of the monomers added in the preparation of the binder composition, the percentage of monomers deriving into structural unit (c) is more than 38%, more than 39%, more than 40%, more than 41%, more than 42%, more than 43%, more than 44%, more than 45%, more than 46%, more than 47%, more than 48%, more than 49%, more than 50%, more than 51%, more than 52%, more than 53%, more than 54%, more than 55%, more than 56%, or more than 57% by weight.

[0091] In some embodiments, monomers derived into structural unit (a), monomers derived into structural unit (b), monomers derived into structural unit (c), or combinations thereof, may be added to a first suspension to form a second suspension without forming a third and fourth suspension. In other embodiments, monomers derived into structural unit (a), monomers derived into structural unit (b), monomers derived into structural unit (c), or combinations thereof, are added sequentially to a first suspension to form a second, third, or fourth suspension. Stirring or dispersion may be performed between additions. This is advantageous because it allows for better dispersion of the material. When monomers are added sequentially, the formation of a third or fourth suspension can be omitted.

[0092] In some embodiments, the stirring time of the fourth suspension is about 5 minutes to about 30 minutes, about 5 minutes to about 28 minutes, about 5 minutes to about 26 minutes, about 5 minutes to about 24 minutes, about 5 minutes to about 22 minutes, about 5 minutes to about 20 minutes, about 5 minutes to about 18 minutes, or about 5 minutes to about 15 minutes. In some embodiments, the stirring time of the fourth suspension is 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 stirring time of the fourth suspension is more than 5 minutes, more than 7 minutes, more than 10 minutes, more than 12 minutes, more than 14 minutes, more than 16 minutes, more than 18 minutes, more than 20 minutes, more than 22 minutes, more than 24 minutes, more than 26 minutes, or more than 28 minutes.

[0093] In some embodiments, the stirring speed of the fourth suspension is 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 stirring speed of the fourth suspension is 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 stirring speed of the fourth suspension is 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.

[0094] In some embodiments, copolymers are obtained by polymerization of a monomer mixture. In some embodiments, the monomer mixture comprises monomers derived into structural unit (a), monomers derived into structural unit (b), and monomers derived into structural unit (c). In some embodiments, the acid-containing monomers derived into structural unit (a) are neutralized by a first neutralizing agent added in step 101, and the acid groups are converted into corresponding salts. Therefore, the salt may be a salt of the acid that forms the monomer derived into structural unit (a) as listed above.

[0095] In some embodiments, the salt contains an alkali metal cation. Examples of alkali metals include lithium, sodium, and potassium. In some embodiments, the salt contains an ammonium cation.

[0096] In some embodiments, the molar ratio of the acid group to its corresponding salt in the composition for a monomer containing an acid group is about 0 to about 0.8, about 0 to about 0.78, about 0 to about 0.76, about 0 to about 0.74, about 0 to about 0.72, about 0 to about 0.7, about 0 to about 0.68, about 0 to about 0.66, about 0 to about 0.64, about 0 to about 0.62, about 0 to about 0.6, about 0 to about 0.58, about 0 to about 0.56, about 0 to about 0.54, about 0 to about 0.52, about 0 to about 0.5, about 0 to about 0.48, about 0 to about 0.46, about 0 to about 0.44, about 0 to about 0.42, about 0 to about 0.4, about 0 to about 0.38, about 0 to about 0.36, about 0 to about 0.34, about 0 to about 0.32, about 0 to about 0.3, about 0.02 to about 0.3, about 0.04 to about 0.3, about 0.06 to about 0.3, about 0.08 to about 0.3, about 0.1 to about 0.3, about 0.05 to about 0.5 or about 0.05 to about 0.4.

[0097] In some embodiments, the molar ratio of the acid group to its corresponding salt in the composition of the monomer containing an acid group 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 acid group to its corresponding salt in the composition of the monomer containing an acid group 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.

[0098] In some embodiments, the initiator solution is added to the fourth suspension in step 105 to form the fifth suspension. In some embodiments, the initiator solution is prepared by dissolving an initiator in water. In other embodiments, the initiator solution is divided into multiple portions and added sequentially to the fourth suspension to form the fifth suspension. Stirring or dispersion may be performed between the addition batches.

[0099] The polymerization occurring in this invention follows a free radical mechanism, where the initiator generates free radicals, leading to polymer chain propagation. The free radicals used herein can be generated through thermal decomposition or redox reactions. The free radical initiators disclosed herein are water-soluble.

[0100] Water-soluble free radical initiators undergo thermal decomposition in an aqueous phase to generate free radicals capable of initiating polymerization. In some embodiments, the water-soluble initiator may be selected from persulfate-based initiators, such as ammonium persulfate, sodium persulfate, potassium persulfate, etc.; azo-based initiators, such as azobis(isobutylamidine hydrochloride) (AIBA), 2,2′-azobis(2-methylpropylamidine) dihydrochloride, 2,2′-azobis(2-amidine propane) dihydrochloride (AAPH), 2,2'-azobis[2-(2-imidazolin-2-yl)propane] dihydrochloride, bis[2-(4'-sulfophenyl)alkyl]-2,2′-azobisisobutyrate ammonium salt (bis[2-(4'-sulfophenyl)alkyl]-2,2'-azodiisobutyrate ammonium salt). Salts), 2,2′-azobis(N-2′-methylpropionyl-2-amino-alkyl-1)-sulfonates, etc.; peroxide-based initiators such as hydrogen peroxide, tert-butanol peroxide, succinic acid peroxide, etc.; and combinations thereof.

[0101] In some implementations, water-soluble free radical initiators can be used in conjunction with reducing agents to establish a redox initiator system. This allows for the generation of free radicals via redox reactions at relatively low temperatures and improves the polymerization rate.

[0102] In some embodiments, the reducing agent is dissolved in water to prepare a reducing agent solution. In some embodiments, the reducing agent may be selected from the group consisting of sodium bisulfite, sodium metabisulfite, sodium sulfite, sodium thiosulfate, thiourea dioxide, ferrous sulfate, ferrous chloride, ascorbic acid, citric acid, tartaric acid, isoascorbic acid, glucose, metal salts of formaldehyde hydrogen sulfide, Bruggolite FF6M, and combinations thereof.

[0103] In some embodiments, when using a redox initiation system, the molar ratio of the water-soluble free radical initiator to the reducing agent is about 0.2 to about 10, about 0.2 to about 9, about 0.2 to about 8, about 0.2 to about 7, about 0.2 to about 6, about 0.2 to about 5, about 0.3 to about 5, about 0.4 to about 5, about 0.5 to about 5, about 0.6 to about 5, about 0.7 to about 5, about 0.8 to about 5, about 0.9 to about 5, about 1 to about 5, about 0.5 to about 4.5, about 0.5 to about 4, about 0.6 to about 3.5, about 0.6 to about 3, about 0.8 to about 3, or about 0.2 to about 1.

[0104] In some embodiments, when using a redox initiation system, 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, less than 2.8, less than 2.6, less than 2.4, less than 2.2, less than 2, less than 1.8, less than 1.6, less than 1.4, less than 1.2, less than 1, less than 0.8, less than 0.6, or less than 0.4. In some embodiments, when using a redox initiation system, 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.

[0105] The polymerization temperature depends on the type of initiator used. In some embodiments, the polymerization reaction temperature is about 40°C to about 80°C, about 40°C to about 78°C, about 40°C to about 75°C, about 40°C to about 72°C, about 40°C to about 70°C, about 40°C to about 68°C, about 40°C to about 65°C, about 40°C to about 62°C, about 40°C to about 60°C, about 50°C to about 80°C, about 50°C to about 78°C, about 50°C to about 75°C, about 50°C to about 72°C, about 50°C to about 70°C, about 50°C to about 68°C, about 50°C to about 65°C, about 50°C to about 62°C, about 50°C to about 60°C, about 60°C to about 80°C, about 60°C to about 78°C, about 60°C to about 75°C, about 60°C to about 72°C, about 60°C to about 70°C, about 60°C to about 68°C, or about 60°C to about 65°C. When the polymerization reaction temperature is within the above range, high reaction stability can be obtained, and the binder composition exhibits good overall bonding performance.

[0106] In some embodiments, the polymerization reaction temperature is below 80°C, below 78°C, below 75°C, below 72°C, below 70°C, below 68°C, below 65°C, below 62°C, below 60°C, below 58°C, below 55°C, below 52°C, below 50°C, below 48°C, below 45°C, or below 42°C. In some embodiments, the polymerization reaction temperature is above 40°C, above 42°C, above 45°C, above 48°C, above 50°C, above 52°C, above 55°C, above 58°C, above 60°C, above 62°C, above 65°C, above 68°C, above 70°C, above 72°C, above 75°C, or above 78°C.

[0107] In some embodiments, the total reaction time of polymerization is about 5 hours to about 30 hours, about 5 hours to about 28 hours, about 5 hours to about 26 hours, about 5 hours to about 24 hours, about 5 hours to about 22 hours, about 5 hours to about 20 hours, about 5 hours to about 18 hours, about 5 hours to about 16 hours, about 5 hours to about 15 hours, about 10 hours to about 30 hours, about 10 hours to about 28 hours, about 10 hours to about 26 hours, about 10 hours to about 24 hours, about 10 hours to about 22 hours, about 10 hours to about 20 hours, about 10 hours to about 18 hours, about 10 hours to about 16 hours, about 10 hours to about 15 hours, about 15 hours to about 30 hours, about 15 hours to about 28 hours, about 15 hours to about 26 hours, about 15 hours to about 24 hours, about 15 hours to about 22 hours, about 15 hours to about 20 hours, about 20 hours to about 30 hours, about 20 hours to about 28 hours, about 20 hours to about 26 hours, or about 20 hours to about 24 hours.

[0108] In some embodiments, the total polymerization reaction time is less than 30 hours, less than 28 hours, less than 26 hours, less than 24 hours, less than 22 hours, less than 20 hours, less than 18 hours, less than 16 hours, less than 15 hours, less than 14 hours, less than 12 hours, or less than 10 hours. In some embodiments, the total polymerization reaction time is more than 5 hours, more than 6 hours, more than 8 hours, more than 10 hours, more than 12 hours, more than 14 hours, more than 15 hours, more than 16 hours, more than 18 hours, more than 20 hours, more than 22 hours, more than 24 hours, or more than 26 hours.

[0109] In some embodiments, the fifth suspension is stirred for about 5 hours to about 30 hours, about 5 hours to about 28 hours, about 5 hours to about 26 hours, about 5 hours to about 24 hours, about 5 hours to about 22 hours, about 5 hours to about 20 hours, about 5 hours to about 18 hours, about 5 hours to about 16 hours, about 5 hours to about 15 hours, about 10 hours to about 30 hours, about 10 hours to about 28 hours, about 10 hours to about 26 hours, about 10 hours to about 24 hours, or about 10 hours to about 22 hours. The time period of about 10 hours to about 20 hours, about 10 hours to about 18 hours, about 10 hours to about 16 hours, about 10 hours to about 15 hours, about 15 hours to about 30 hours, about 15 hours to about 28 hours, about 15 hours to about 26 hours, about 15 hours to about 24 hours, about 15 hours to about 22 hours, about 15 hours to about 20 hours, about 20 hours to about 30 hours, about 20 hours to about 28 hours, about 20 hours to about 26 hours, or about 20 hours to about 24 hours.

[0110] In some embodiments, the fifth suspension is stirred for a period of less than 30 hours, less than 28 hours, less than 26 hours, less than 24 hours, less than 22 hours, less than 20 hours, less than 18 hours, less than 16 hours, less than 15 hours, less than 14 hours, less than 12 hours, or less than 10 hours. In some embodiments, the fifth suspension is stirred for a period of more than 5 hours, more than 6 hours, more than 8 hours, more than 10 hours, more than 12 hours, more than 14 hours, more than 15 hours, more than 16 hours, more than 18 hours, more than 20 hours, more than 22 hours, more than 24 hours, or more than 26 hours.

[0111] In some embodiments, the stirring speed of the fifth suspension is 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.

[0112] In some embodiments, the stirring speed of the fifth suspension is 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 stirring speed of the fifth suspension is greater than 20 rpm, greater than 40 rpm, greater than 60 rpm, greater than 80 rpm, greater than 100 rpm, greater than 120 rpm, greater than 140 rpm, greater than 160 rpm, greater than 180 rpm, greater than 200 rpm, greater than 220 rpm, greater than 240 rpm, greater than 260 rpm, or greater than 280 rpm.

[0113] In some embodiments, based on the total weight of monomers added during the preparation of the binder composition, the proportion of the water-soluble free radical initiator is approximately 0.01% to about 0.5% by weight, approximately 0.02% to about 0.5%, approximately 0.03% to about 0.5%, approximately 0.04% to about 0.5%, approximately 0.05% to about 0.5%, approximately 0.06% to about 0.5%, approximately 0.08% to about 0.5%, or approximately 0.1% by weight. About 0.5%, about 0.12% to about 0.5%, about 0.15% to about 0.5%, about 0.18% to about 0.5%, about 0.2% to about 0.5%, about 0.01% to about 0.36%, about 0.02% to about 0.36%, about 0.03% to about 0.36%, about 0.04% to about 0.36%, about 0.05% to about 0.36%, about 0.06% to about 0.36%, about 0 0.08% to about 0.36%, about 0.1% to about 0.36%, about 0.12% to about 0.36%, about 0.14% to about 0.36%, about 0.16% to about 0.36%, about 0.18% to about 0.36%, about 0.2% to about 0.36%, about 0.01% to about 0.2%, about 0.02% to about 0.2%, about 0.03% to about 0.2%, about 0.04% to about 0.2%. The percentages are approximately 0.05% to approximately 0.2%, approximately 0.06% to approximately 0.2%, approximately 0.08% to approximately 0.2%, approximately 0.1% to approximately 0.2%, approximately 0.01% to approximately 0.1%, approximately 0.02% to approximately 0.1%, approximately 0.03% to approximately 0.1%, approximately 0.04% to approximately 0.1%, approximately 0.05% to approximately 0.1%, approximately 0.06% to approximately 0.1%, or approximately 0.08% to approximately 0.1%. When the proportion of the water-soluble initiator is within the above ranges, a higher monomer conversion rate can be obtained, and the adhesive composition can exhibit better overall adhesive performance.

[0114] In some embodiments, the proportion of the water-soluble free radical initiator, based on the total weight of the monomers added when preparing the binder composition, is less than 0.5%, less than 0.45%, less than 0.4%, less than 0.35%, less than 0.30%, less than 0.25%, less than 0.2%, less than 0.18%, less than 0.16%, less than 0.15%, less than 0.14%, less than 0.12%, less than 0.1%, less than 0.08%, less than 0.06%, less than 0.05%, less than 0.04%, or less than 0.03% by weight. In some embodiments, the proportion of the water-soluble free radical initiator, based on the total weight of the monomers added when preparing the binder composition, is more than 0.01%, more than 0.02%, more than 0.03%, more than 0.04%, more than 0.05%, more than 0.06%, more than 0.08%, more than 0.1%, more than 0.12%, more than 0.14%, more than 0.15%, more than 0.16%, more than 0.18%, more than 0.2%, more than 0.25%, more than 0.30%, more than 0.35%, or more than 0.4% by weight.

[0115] In some embodiments, based on the total weight of monomers added during the preparation of the binder composition, the proportion of reducing agent is approximately 0.001% to approximately 0.03%, approximately 0.002% to approximately 0.03%, approximately 0.005% to approximately 0.03%, approximately 0.008% to approximately 0.03%, approximately 0.01% to approximately 0.03%, approximately 0.012% to approximately 0.03%, approximately 0.015% to approximately 0.03%, approximately 0.001% to approximately 0.028% by weight. About 0.002% to about 0.028%, about 0.005% to about 0.028%, about 0.008% to about 0.028%, about 0.01% to about 0.028%, about 0.012% to about 0.028%, about 0.015% to about 0.028%, about 0.001% to about 0.025%, about 0.002% to about 0.025%, about 0.005% to about 0.025%, about 0.008% to about 0.025%, about 0. 0.01% to about 0.025%, about 0.012% to about 0.025%, about 0.015% to about 0.025%, about 0.001% to about 0.022%, about 0.002% to about 0.022%, about 0.005% to about 0.022%, about 0.008% to about 0.022%, about 0.01% to about 0.022%, about 0.012% to about 0.022%, about 0.001% to about 0.02%, about 0.002% to About 0.02%, about 0.005% to about 0.02%, about 0.008% to about 0.02%, about 0.01% to about 0.02%, about 0.001% to about 0.018%, about 0.002% to about 0.018%, about 0.005% to about 0.018%, about 0.008% to about 0.018%, about 0.001% to about 0.015%, about 0.002% to about 0.015%, or about 0.005% to about 0.015%.

[0116] In some embodiments, the reducing agent accounts for less than 0.03%, less than 0.029%, less than 0.028%, less than 0.027%, less than 0.026%, less than 0.025%, less than 0.024%, less than 0.023%, less than 0.022%, less than 0.021%, less than 0.02%, less than 0.019%, less than 0.018%, less than 0.017%, less than 0.016%, less than 0.015%, less than 0.014%, less than 0.013%, less than 0.012%, less than 0.011%, less than 0.01%, less than 0.008%, or less than 0.005% by weight, based on the total weight of the monomers added when preparing the binder composition. In some embodiments, the reducing agent accounts for more than 0.001%, more than 0.002%, more than 0.005%, more than 0.006%, more than 0.007%, more than 0.008%, more than 0.009%, more than 0.01%, more than 0.011%, more than 0.012%, or more than 0.01% by weight, based on the total weight of the monomers added when preparing the binder composition. 3%, more than 0.014%, more than 0.015%, more than 0.016%, more than 0.017%, more than 0.018%, more than 0.019%, more than 0.02%, more than 0.021%, more than 0.022%, more than 0.023%, more than 0.024%, more than 0.025%, more than 0.026%, more than 0.027%, or more than 0.028%.

[0117] In some embodiments, in step 106, the second neutralizing solution is added dropwise to the fifth suspension to form a sixth suspension. In some embodiments, the second neutralizing agent is dissolved in water to prepare the second neutralizing solution. In some embodiments, the first and second neutralizing agents are the same. In some embodiments, the first and second neutralizing agents are not the same.

[0118] In some embodiments, before adding the second neutralizing solution to form the sixth suspension, 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. In some embodiments, before adding the second neutralizing solution to form the sixth suspension, the temperature of the fifth suspension is reduced to below 40°C, below 39°C, below 38°C, below 37°C, below 36°C, below 35°C, below 34°C, below 33°C, below 32°C, below 31°C, below 30°C, below 29°C, below 28°C, below 27°C, below 26°C, below 25°C, below 24°C, below 23°C, below 22°C, or below 21°C. In some embodiments, before adding the second neutralizing solution to form the sixth suspension, the temperature of the fifth suspension is lowered to above 20°C, above 21°C, above 22°C, above 23°C, above 24°C, above 25°C, above 26°C, above 27°C, above 28°C, above 29°C, above 30°C, above 31°C, above 32°C, above 33°C, above 34°C, above 35°C, above 36°C, above 37°C, above 38°C, or above 39°C.

[0119] In some embodiments, the proportion of the second neutralizing agent, based on the total molar number of monomer units in the copolymer of the adhesive composition, is approximately 15% to 60%, approximately 15% to 58%, approximately 15% to 55%, approximately 15% to 52%, approximately 15% to 50%, approximately 15% to 48%, approximately 15% to 45%, approximately 15% to 42%, approximately 15% to 40%, approximately 15% to 38%, approximately 15% to 35%, approximately 15% to 32%, approximately 15% to 30%, approximately 20% to 60%, approximately 20% to 58%, approximately 20% to 55%, approximately 20% to approximately 52%, about 20% to about 50%, about 20% to about 48%, about 20% to about 45%, about 20% to about 42%, about 20% to about 40%, about 20% to about 38%, about 20% to about 35%, about 25% to about 60%, about 25% to about 50%, about 25% to about 48%, about 25% to about 45%, about 25% to about 42%, about 25% to about 40%, about 25% to about 38%, about 25% to about 35%, about 30% to about 60%, about 30% to about 50%, about 30% to about 48%, about 30% to about 45%, about 30% to about 42%, or about 30% to about 40%.

[0120] In some embodiments, the total proportion of the second neutralizing agent, based on the total molar number of monomer units in the copolymer of the binder composition, is less than 60%, less than 58%, less than 55%, less than 52%, less than 50%, less than 48%, less than 45%, less than 42%, less than 40%, less than 38%, less than 35%, less than 32%, less than 30%, less than 28%, less than 25%, less than 22%, less than 20%, or less than 18% on a molar basis. In some embodiments, the total proportion of the second neutralizing agent, based on the total molar number of monomer units in the copolymer of the binder composition, is more than 15%, more than 18%, more than 20%, more than 22%, more than 25%, more than 28%, more than 30%, more than 32%, more than 35%, more than 38%, more than 40%, more than 42%, more than 45%, more than 48%, more than 50%, more than 52%, more than 55%, or more than 58% by molar weight.

[0121] In some embodiments, the second neutralizing solution is added to the fifth suspension by dropwise addition. In some embodiments, the time period for adding the second neutralizing solution to the fifth suspension is about 15 minutes to about 120 minutes, about 20 minutes to about 120 minutes, about 30 minutes to about 120 minutes, about 40 minutes to about 120 minutes, about 50 minutes to about 120 minutes, about 60 minutes to about 120 minutes, about 15 minutes to about 90 minutes, about 20 minutes to about 90 minutes, about 30 minutes to about 90 minutes, about 40 minutes to about 90 minutes, about 45 minutes to about 90 minutes, about 50 minutes to about 90 minutes, about 15 minutes to about 60 minutes, about 20 minutes to about 60 minutes, or about 30 minutes to about 60 minutes. In some embodiments, the time period for adding the second neutralizing solution to the fifth suspension is 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 time period for adding the second neutralizing solution to the fifth suspension is more than 15 minutes, more than 20 minutes, more than 30 minutes, more than 40 minutes, more than 50 minutes, more than 60 minutes, more than 70 minutes, more than 80 minutes, or more than 90 minutes.

[0122] In some embodiments, after the addition of the second neutralizing solution is initiated, the fifth suspension is stirred for a period of approximately 1 hour to approximately 6 hours, approximately 1 hour to approximately 5.5 hours, approximately 1 hour to approximately 5 hours, approximately 1 hour to approximately 4.5 hours, approximately 1 hour to approximately 4 hours, approximately 1 hour to approximately 3.5 hours, approximately 1 hour to approximately 3 hours, approximately 1.5 hours to approximately 6 hours, approximately 1.5 hours to approximately 5.5 hours, approximately 1.5 hours to approximately 5 hours, approximately 1.5 hours to approximately 4.5 hours, approximately 1.5 hours to approximately 4 hours, approximately 1.5 hours to approximately 3.5 hours, approximately 1.5 hours to approximately 3 hours, approximately 2 hours to approximately 6 hours, approximately 2 hours to approximately 5.5 hours, approximately 2 hours to approximately 5 hours, approximately 2 hours to approximately 4.5 hours, or approximately 2 hours to approximately 4 hours.

[0123] In some embodiments, after the addition of the second neutralizing solution, the fifth suspension is stirred for a period of less than 6 hours, less than 5.5 hours, less than 5 hours, less than 4.5 hours, less than 4 hours, less than 3.5 hours, less than 3 hours, less than 2.5 hours, less than 2 hours, or less than 1.5 hours. In some embodiments, after the addition of the second neutralizing solution, the fifth suspension is stirred for a period of more than 1 hour, more than 1.5 hours, more than 2 hours, more than 2.5 hours, more than 3 hours, more than 3.5 hours, more than 4 hours, more than 4.5 hours, more than 5 hours, more than 5.25 hours, or more than 5.5 hours.

[0124] In some embodiments, the stirring speed of the fifth suspension is 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.

[0125] In some embodiments, the stirring speed of the fifth suspension is 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 stirring speed of the fifth suspension is greater than 20 rpm, greater than 40 rpm, greater than 60 rpm, greater than 80 rpm, greater than 100 rpm, greater than 120 rpm, greater than 140 rpm, greater than 160 rpm, greater than 180 rpm, greater than 200 rpm, greater than 220 rpm, greater than 240 rpm, greater than 260 rpm, or greater than 280 rpm.

[0126] In some embodiments, the binder composition is formed in step 107 by filtering the sixth suspension.

[0127] The purpose of adding the first and second neutralizing agents in steps 101 and 106, respectively, is to neutralize the monomers containing acidic groups in order to produce a binder composition that is slightly alkaline in nature. Exposing the binder composition to acidic conditions is undesirable because it may disrupt the dispersibility of the binder composition.

[0128] After neutralization, the acid groups in structural unit (a) of the copolymer may be partially or completely converted into their corresponding salts. In some embodiments, the salt contains an alkali metal cation. Examples of alkali metals include lithium, sodium, and potassium. In some embodiments, the salt contains an ammonium cation.

[0129] In some embodiments, the molar ratio of the acid group to its corresponding salt, with respect to the neutralized copolymer, is about 0 to about 0.2, about 0 to about 0.19, about 0 to about 0.18, about 0 to about 0.17, about 0 to about 0.16, about 0 to about 0.15, about 0 to about 0.14, about 0 to about 0.13, about 0 to about 0.12, about 0 to about 0.11, about 0 to about 0.1, about 0 to about 0.09, about 0 to about 0.08, about 0 to about 0.07, about 0 to about 0.06, about 0 to about 0.05, about 0.01 to about 0.1, about 0.02 to about 0.12, or about 0.01 to about 0.15.

[0130] In some embodiments, the molar ratio of the acid group to its corresponding salt 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 with respect to the neutralized copolymer. In some embodiments, the molar ratio of the acid group to its corresponding salt 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 with respect to the neutralized copolymer.

[0131] In some embodiments, based on the total molar number of monomer units in the copolymer of the adhesive composition, the proportion of structural unit (a) in the copolymer is approximately 15% to approximately 50%, approximately 15% to approximately 48%, approximately 15% to approximately 45%, approximately 15% to approximately 42%, approximately 15% to approximately 40%, approximately 15% to approximately 38%, approximately 15% to approximately 35%, approximately 15% to approximately 32%, approximately 15% to approximately 30%, approximately 15% to approximately 28%, approximately 15% to approximately 25%, approximately 20% to approximately 50%, approximately 20% to approximately 48 ... % to about 45%, about 20% to about 42%, about 20% to about 40%, about 20% to about 38%, about 20% to about 35%, about 20% to about 32%, about 20% to about 30%, about 25% to about 50%, about 25% to about 48%, about 25% to about 45%, about 25% to about 42%, about 25% to about 40%, about 25% to about 38%, about 25% to about 35%, about 30% to about 50%, about 30% to about 48%, about 30% to about 45%, about 30% to about 42% or about 30% to about 40%.

[0132] In some embodiments, based on the total molar number of monomer units in the copolymer of the binder composition, the proportion of structural unit (a) in the copolymer is less than 50%, less than 48%, less than 45%, less than 42%, less than 40%, less than 38%, less than 35%, less than 32%, less than 30%, less than 28%, less than 25%, less than 22%, less than 20%, or less than 18% by molar. In some embodiments, based on the total molar number of monomer units in the copolymer of the binder composition, the proportion of structural unit (a) in the copolymer is more than 15%, more than 18%, more than 20%, more than 22%, more than 25%, more than 28%, more than 30%, more than 32%, more than 35%, more than 38%, more than 40%, more than 42%, more than 45%, or more than 48% by molar.

[0133] In some embodiments, based on the total molar number of monomer units in the copolymer of the binder composition, the proportion of structural unit (b) in the copolymer is, on a molar basis, about 4% to about 25%, about 4% to about 24%, about 4% to about 23%, about 4% to about 22%, about 4% to about 21%, about 4% to about 20%, about 4% to about 19%, about 4% to about 18%, about 4% to about 17%, about 4% to about 16%, about 4% to about 15%, about 4% to about 14%, about 4% to about 13%, about 7% to about 25%, about 7% to about 24%, about 7% to about 23%, about 7% to about 22%, about 7% to about 21%, about 7% to about 20%, about 7% to about 19%, about 7% to about 18%, about 7% to about 17%. %, about 7% to about 16%, about 7% to about 15%, about 10% to about 25%, about 10% to about 24%, about 10% to about 23%, about 10% to about 22%, about 10% to about 21%, about 10% to about 20%, about 10% to about 19%, about 10% to about 18%, about 10% to about 17%, about 10% to about 16%, about 10% to about 15%, about 13% to about 25%, about 13% to about 24%, about 13% to about 23%, about 13% to about 22%, about 13% to about 21%, about 13% to about 20%, about 15% to about 25%, about 15% to about 24%, about 15% to about 23%, about 15% to about 22%, about 15% to about 21%, or about 15% to about 20%.

[0134] In some embodiments, based on the total molar number of monomer units in the copolymer in the binder composition, the proportion of structural unit (b) in the copolymer is less than 25%, less than 24%, less than 23%, less than 22%, less than 21%, less than 20%, less than 19%, less than 18%, less than 17%, less than 16%, less than 15%, less than 14%, less than 13%, less than 12%, less than 11%, less than 10%, less than 9%, less than 8%, less than 7%, less than 6%, or less than 5% on a molar basis. In some embodiments, based on the total molar number of monomer units in the copolymer in the binder composition, the proportion of structural unit (b) in the copolymer is greater than 4%, greater than 5%, greater than 6%, greater than 7%, greater than 8%, greater than 9%, greater than 10%, greater than 11%, greater than 12%, greater than 13%, greater than 14%, greater than 15%, greater than 16%, greater than 17%, greater than 18%, greater than 19%, greater than 20%, greater than 21%, greater than 22%, greater than 23%, or greater than 24% on a molar basis.

[0135] In some embodiments, based on the total molar number of monomer units in the copolymer of the binder composition, the proportion of structural unit (c) in the copolymer is about 46% to about 65%, about 46% to about 64%, about 46% to about 63%, about 46% to about 62%, about 46% to about 61%, about 46% to about 60%, about 46% to about 59%, about 46% to about 58%, about 46% to about 57%, about 46% to about 56%, about 50% (on a molar basis). % to 65%, about 50% to 64%, about 50% to 63%, about 50% to 62%, about 50% to 61%, about 50% to 60%, about 50% to 59%, about 50% to 58%, about 50% to 57%, about 50% to 56%, about 55% to 65%, about 55% to 64%, about 55% to 63%, about 55% to 62%, about 55% to 61%, or about 55% to 60%.

[0136] In some embodiments, based on the total molar number of monomer units in the copolymer in the binder composition, the proportion of structural units (c) in the copolymer is less than 65%, less than 64%, less than 63%, less than 62%, less than 61%, less than 60%, less than 59%, less than 58%, less than 57%, less than 56%, less than 55%, less than 54%, less than 53%, less than 52%, less than 51%, less than 50%, less than 49%, less than 48%, or less than 47% on a molar basis. In some embodiments, based on the total molar number of monomer units in the copolymer in the binder composition, the proportion of structural units (c) in the copolymer is greater than 46%, greater than 47%, greater than 48%, greater than 49%, greater than 50%, greater than 51%, greater than 52%, greater than 53%, greater than 54%, greater than 55%, greater than 56%, greater than 57%, greater than 58%, greater than 59%, greater than 60%, greater than 61%, greater than 62%, greater than 63%, or greater than 64% on a molar basis.

[0137] In some embodiments, structural units (a) and (b) constitute the hydrophilic portion of the copolymer. In some embodiments, structural unit (c) constitutes the hydrophobic portion of the copolymer.

[0138] In some embodiments, based on the total molar number of monomer units in the copolymer of the adhesive composition, the proportion of the sum of structural units (a) and structural units (b) in the copolymer is approximately 35% to 54%, approximately 35% to 53%, approximately 35% to 52%, approximately 35% to 51%, approximately 35% to 50%, approximately 35% to 49%, approximately 35% to 48%, approximately 35% to 47%, approximately 35% to 46%, approximately 35% to 45%, approximately 38% to 54%, approximately 38% to 53%, approximately 38% to 52%, approximately 38% to 51%, approximately 38% to 50%, approximately 38% to 49%, approximately 38% to 48%, and approximately 38% to 47% (on a molar basis). %, about 38% to about 46%, about 38% to about 45%, about 40% to about 54%, about 40% to about 53%, about 40% to about 52%, about 40% to about 51%, about 40% to about 50%, about 40% to about 49%, about 40% to about 48%, about 40% to about 47%, about 40% to about 46%, about 40% to about 45%, about 42% to about 54%, about 42% to about 53%, about 42% to about 52%, about 42% to about 51%, about 42% to about 50%, about 42% to about 49%, about 42% to about 48%, about 45% to about 54%, about 45% to about 53%, about 45% to about 52%, about 45% to about 51%, or about 45% to about 50%.

[0139] In some embodiments, based on the total molar number of monomer units in the copolymer in the binder composition, the percentage of the sum of structural units (a) and structural units (b) in the copolymer is less than 54%, less than 53%, less than 52%, less than 51%, less than 50%, less than 49%, less than 48%, less than 47%, less than 46%, less than 45%, less than 44%, less than 43%, less than 42%, less than 41%, less than 40%, less than 39%, less than 38%, less than 37%, or less than 36% on a molar basis. In some embodiments, based on the total molar number of monomer units in the copolymer of the binder composition, the percentage of the sum of structural units (a) and structural units (b) in the copolymer is greater than 35%, greater than 36%, greater than 37%, greater than 38%, greater than 39%, greater than 40%, greater than 41%, greater than 42%, greater than 43%, greater than 44%, greater than 45%, greater than 46%, greater than 47%, greater than 48%, greater than 49%, greater than 50%, greater than 51%, greater than 52%, or greater than 53% in molar.

[0140] When the sum of structural units (a) and (b) in the copolymer of the binder composition is too high, processing the binder composition and the slurry containing it becomes more difficult. Furthermore, electrodes made from such slurries are found to be prone to breakage, resulting in poor electrochemical performance of the battery. On the other hand, when the sum of structural units (a) and (b) in the copolymer of the binder composition is too low, the binder composition exhibits poor dispersibility in the slurry, which also impairs the electrochemical performance of the battery. Therefore, the sum of structural units (a) and (b) in the copolymer of the binder composition is crucial.

[0141] In some embodiments, the molar ratio of the sum of structural units (a) and (b) to structural unit (c) in the copolymer is about 0.5 to about 1.2, about 0.5 to about 1.15, about 0.5 to about 1.1, about 0.5 to about 1.05, about 0.5 to about 1, about 0.5 to about 0.95, about 0.5 to about 0.9, about 0.5 to about 0.85, about 0.5 to about 0.8, about 0.5 to about 0.75, about 0.5 to about 0.7, about 0.65 to about 1.2, about 0.65 to about 1.15, or about 0.65. From to about 1.1, from about 0.65 to about 1.05, from about 0.65 to about 1, from about 0.65 to about 0.95, from about 0.65 to about 0.9, from about 0.65 to about 0.85, from about 0.65 to about 0.8, from about 0.65 to about 0.75, from about 0.8 to about 1.2, from about 0.8 to about 1.15, from about 0.8 to about 1.1, from about 0.8 to about 1.05, from about 0.8 to about 1, from about 0.9 to about 1.2, from about 0.9 to about 1.15, from about 0.9 to about 1.1, from about 0.9 to about 1.05, or from about 0.9 to about 1.

[0142] In some embodiments, the molar ratio of the sum of structural units (a) and (b) to structural unit (c) in the copolymer is less than 1.2, less than 1.15, less than 1.1, less than 1.05, less than 1, less than 0.95, less than 0.9, less than 0.85, less than 0.8, less than 0.75, less than 0.7, less than 0.65, less than 0.6, or less than 0.55. In some embodiments, the molar ratio of the sum of structural units (a) and (b) to structural unit (c) in the copolymer is greater than 0.5, greater than 0.55, greater than 0.6, greater than 0.65, greater than 0.7, greater than 0.75, greater than 0.8, greater than 0.85, greater than 0.9, greater than 0.95, greater than 1, greater than 1.05, greater than 1.1, or greater than 1.15.

[0143] It has been found that the addition of monomers containing ester groups in the preparation of the adhesive compositions disclosed herein leads to a deterioration in electrochemical performance. In some embodiments, the adhesive compositions do not contain structural units derived from monomers containing ester groups. In some embodiments, the monomers containing ester groups are C1-C... 20 Alkyl acrylate, C1-C 20Alkyl methacrylates, cycloalkyl acrylates, or combinations thereof. In some embodiments, the monomers containing ester groups are 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, dodecyl acrylate, n-tetradecyl acrylate, octadecyl acrylate, cyclohexyl acrylate, phenyl acrylate, methoxymethyl acrylate, methoxyethyl acrylate, ethoxymethyl acrylate, ethoxyethyl acrylate, perfluorooctyl acrylate, stearate acrylate, or combinations thereof. In some embodiments, the monomers containing ester groups are cyclohexyl acrylate, cyclohexyl methacrylate, isobornyl acrylate, isobornyl methacrylate, 3,3,5-trimethylcyclohexyl acrylate, or combinations thereof. In some embodiments, the monomer containing the ester group 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, stearate methacrylate, 2,2,2-trifluoroethyl methacrylate, phenyl methacrylate, benzyl methacrylate, or a combination thereof.

[0144] In some embodiments, the adhesive composition does not contain structural units derived from monomers containing conjugated diene groups. Examples of monomers containing conjugated diene groups 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 branched conjugated hexadiene.

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

[0146] In some embodiments, the pH of the adhesive composition is about 7 to about 10, about 7.2 to about 10, about 7.4 to about 10, about 7.5 to about 10, about 7.6 to about 10, about 7.8 to about 10, about 8 to about 10, about 8.2 to about 10, about 8.4 to about 10, about 8.5 to about 10, about 7 to about 9.5, about 7.2 to about 9.5, about 7.4 to about 9.5, about 7.5 to about 9.5, about 7.6 to about 9.5, about 7.8 to about 9.5, about 8 to about 9.5, about 7 to about 9, about 7.2 to about 9, about 7.4 to about 9, about 7.5 to about 9, about 7.6 to about 9, about 7.8 to about 9, about 8 to about 9, about 7 to about 8.5, about 7.2 to about 8.5, about 7.4 to about 8.5, or about 7.5 to about 8.5.

[0147] In some embodiments, the pH of the adhesive composition is less than 10, less than 9.8, less than 9.5, less than 9.2, less than 9, less than 8.8, less than 8.6, less than 8.5, less than 8.4, less than 8.2, 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, or less than 7.2. In some embodiments, the pH of the adhesive composition is greater than 7, greater than 7.2, 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 8.2, greater than 8.4, greater than 8.5, greater than 8.6, greater than 8.8, greater than 9, greater than 9.2, greater than 9.5, or greater than 9.8.

[0148] In some embodiments, the viscosity of the binder composition is about 5,000 mPa·s to about 25,000 mPa·s, about 6,000 mPa·s to about 25,000 mPa·s, about 8,000 mPa·s to about 25,000 mPa·s, about 10,000 mPa·s to about 25,000 mPa·s, about 12,000 mPa·s to about 25,000 mPa·s, about 14,000 mPa·s to about 25,000 mPa·s, about 15,000 mPa·s to about 25,000 mPa·s, and so on. 000 mPa·s, about 16,000 mPa·s to about 25,000 mPa·s, about 18,000 mPa·s to about 25,000 mPa·s, about 20,000 mPa·s to about 25,000 mPa·s, about 5,000 mPa·s to about 22,000 mPa·s, about 6,000 mPa·s to about 22,000 mPa·s, about 8,000 mPa·s to about 22,000 mPa·s, about 10,000 mPa·s to about 22,000 mPa·s, about 1 2,000 mPa·s to about 22,000 mPa·s, about 14,000 mPa·s to about 22,000 mPa·s, about 15,000 mPa·s to about 22,000 mPa·s, about 5,000 mPa·s to about 20,000 mPa·s, about 6,000 mPa·s to about 20,000 mPa·s, about 8,000 mPa·s to about 20,000 mPa·s, about 10,000 mPa·s to about 20,000 mPa·s, about 12,000 mPa·s The viscosity ranges from approximately 20,000 mPa·s, approximately 5,000 mPa·s to approximately 18,000 mPa·s, approximately 6,000 mPa·s to approximately 18,000 mPa·s, approximately 8,000 mPa·s to approximately 18,000 mPa·s, approximately 10,000 mPa·s to approximately 18,000 mPa·s, approximately 5,000 mPa·s to approximately 15,000 mPa·s, approximately 6,000 mPa·s to approximately 15,000 mPa·s, or approximately 8,000 mPa·s to approximately 15,000 mPa·s. When the viscosity of the adhesive composition is within the above-mentioned ranges, the processability of the adhesive composition is optimized.

[0149] In some embodiments, the viscosity of the binder composition is less than 25,000 mPa·s, less than 24,000 mPa·s, less than 23,000 mPa·s, less than 22,000 mPa·s, less than 21,000 mPa·s, less than 20,000 mPa·s, less than 19,000 mPa·s, less than 18,000 mPa·s, less than 17,000 mPa·s, less than 16,000 mPa·s, less than 15,000 mPa·s, less than 14,000 mPa·s, less than 13,000 mPa·s, less than 12,000 mPa·s, less than 11,000 mPa·s, less than 10,000 mPa·s, less than 9,000 mPa·s, less than 8,000 mPa·s, or less than 7,000 mPa·s. In some embodiments, the viscosity of the binder composition is greater than 5,000 mPa·s, greater than 6,000 mPa·s, greater than 7,000 mPa·s, greater than 8,000 mPa·s, greater than 9,000 mPa·s, greater than 10,000 mPa·s, greater than 11,000 mPa·s, greater than 12,000 mPa·s, greater than 13,000 mPa·s, greater than 14,000 mPa·s, greater than 15,000 mPa·s, greater than 16,000 mPa·s, greater than 17,000 mPa·s, greater than 18,000 mPa·s, greater than 19,000 mPa·s, greater than 20,000 mPa·s, greater than 21,000 mPa·s, greater than 22,000 mPa·s, or greater than 23,000 mPa·s.

[0150] In some embodiments, based on the total weight of the adhesive composition, the solids content of the adhesive composition is, by weight, about 1% to about 20%, about 3% to about 20%, about 5% to about 20%, about 6% to about 20%, about 7% to about 20%, about 7.5% to about 20%, about 8% to about 20%, about 8.5% to about 20%, about 9% to about 20%, about 9.5% to about 20%, about 10% to about 20%, about 1% to about 15%, or about 3% to about 15%. About 5% to about 15%, about 6% to about 15%, about 7% to about 15%, about 7.5% to about 15%, about 8% to about 15%, about 8.5% to about 15%, about 9% to about 15%, about 10% to about 15%, about 1% to about 13%, about 3% to about 13%, about 5% to about 13%, about 7% to about 13%, about 7.5% to about 13%, about 8% to about 13%, about 1% to about 10%, about 3% to about 10%, or about 5% to about 10%.

[0151] In some embodiments, the solids content of the adhesive composition, based on the total weight of the adhesive composition, is less than 20%, less than 18%, less than 16%, less than 14%, less than 13%, less than 12%, less than 11%, less than 10%, less than 9.5%, less than 9%, less than 8.5%, less than 8%, less than 7.5%, less than 7%, less than 6%, less than 5%, or less than 3% by weight. In some embodiments, the solids content of the adhesive composition, based on the total weight of the adhesive composition, is more than 1%, more than 3%, more than 5%, more than 6%, more than 7%, more than 7.5%, more than 8%, more than 8.5%, more than 9%, more than 9.5%, more than 10%, more than 11%, more than 12%, more than 13%, more than 14%, more than 16%, or more than 18% by weight.

[0152] In some embodiments, the weight-average molecular weight of the binder composition is about 100,000 g / mol to about 200,000 g / mol, about 110,000 g / mol to about 200,000 g / mol, about 120,000 g / mol to about 200,000 g / mol, about 130,000 g / mol to about 200,000 g / mol, about 140,000 g / mol to about 200,000 g / mol, about 150,000 g / mol to about 200,000 g / mol, about 160,000 g / mol to about 200,000 g / mol, about 170,000 g / mol to about 200,000 g / mol, and about 10. The weight-average molecular weight of the adhesive composition is from 0,000 g / mol to about 180,000 g / mol, from about 110,000 g / mol to about 180,000 g / mol, from about 120,000 g / mol to about 180,000 g / mol, from about 130,000 g / mol to about 180,000 g / mol, from about 140,000 g / mol to about 180,000 g / mol, from about 150,000 g / mol to about 180,000 g / mol, from about 100,000 g / mol to about 150,000 g / mol, from about 110,000 g / mol to about 150,000 g / mol, or from about 120,000 g / mol to about 150,000 g / mol. When the weight-average molecular weight of the adhesive composition is within the above range, the adhesive strength of the adhesive composition is improved.

[0153] In some embodiments, the binder composition has a weight-average molecular weight of 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, or less than 110,000 g / mol. In some embodiments, the binder composition has a weight-average molecular weight greater than 100,000 g / mol, greater than 105,000 g / mol, greater than 110,000 g / mol, greater than 115,000 g / mol, greater than 120,000 g / mol, greater than 125,000 g / mol, greater than 130,000 g / mol, greater than 135,000 g / mol, greater than 140,000 g / mol, greater than 145,000 g / mol, greater than 150,000 g / mol, greater than 155,000 g / mol, greater than 160,000 g / mol, greater than 165,000 g / mol, greater than 170,000 g / mol, greater than 175,000 g / mol, greater than 180,000 g / mol, greater than 185,000 g / mol, or greater than 190,000 g / mol.

[0154] In some embodiments, the number average molecular weight of the binder composition is about 30,000 g / mol to about 100,000 g / mol, about 35,000 g / mol to about 100,000 g / mol, about 40,000 g / mol to about 100,000 g / mol, about 45,000 g / mol to about 100,000 g / mol, about 50,000 g / mol to about 100,000 g / mol, about 55,000 g / mol to about 100,000 g / mol, about 60,000 g / mol to about 100,000 g / mol, about 65,000 g / mol to about 100,000 g / mol, about 70,000 g / mol to about 100,000 g / mol, about 75,000 g / mol to about 100,000 g / mol, or about 40,000 g / mol. about 85,000 g / mol, about 45,000 g / mol to about 85,000 g / mol, about 50,000 g / mol to about 85,000 g / mol, about 55,000 g / mol to about 85,000 g / mol, about 60,000 g / mol to about 85,000 g / mol, about 65,000 g / mol to about 85,000 g / mol, about 70,000 g / mol to about 85,000 g / mol, about 40,000 g / mol to about 75,000 g / mol, about 45,000 g / mol to about 75,000 g / mol, about 50,000 g / mol to about 75,000 g / mol, about 55,000 g / mol to about 75,000 g / mol, or about 60,000 g / mol to about 75,000 g / mol. When the number average molecular weight of the adhesive composition is within the above-mentioned range, the adhesive strength of the adhesive composition is improved.

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

[0156] In some embodiments, the polydispersity index (PDI) of the binder composition is about 1 to about 5, about 1 to about 4.8, about 1 to about 4.6, about 1 to about 4.5, about 1 to about 4.4, about 1 to about 4.2, about 1 to about 4, about 1 to about 3.8, about 1 to about 3.6, about 1 to about 3.5, about 1 to about 3.4, about 1 to about 3.2, about 1 to about 3, about 1.3 to about 5, about 1.3 to about 4.8, about 1.3 to about 4.6, about 1.3 to about 4.5, about 1.3 to about 4.4, about 1.3 to about 4.2, about 1.3 to about 4, about 1.3 to about 3.8, about 1.3 to about 3.6, about 1.3 to about 3.5, about 1.3 to about 3.4, about 1.3 to about 3.2, about 1.3. The polydispersity index of the adhesive composition is approximately 3, approximately 1.5 to approximately 5, approximately 1.5 to approximately 4.8, approximately 1.5 to approximately 4.6, approximately 1.5 to approximately 4.5, approximately 1.5 to approximately 4.4, approximately 1.5 to approximately 4.2, approximately 1.5 to approximately 4, approximately 1.5 to approximately 3.8, approximately 1.5 to approximately 3.6, approximately 1.5 to approximately 3.5, approximately 1.5 to approximately 3.4, approximately 1.5 to approximately 3.2, approximately 1.5 to approximately 3, approximately 1.8 to approximately 5, approximately 1.8 to approximately 4.8, approximately 1.8 to approximately 4.6, approximately 1.8 to approximately 4.5, approximately 1.8 to approximately 4.4, approximately 1.8 to approximately 4.2, approximately 1.8 to approximately 4, approximately 2 to approximately 5, approximately 2 to approximately 4.8, approximately 2 to approximately 4.6, approximately 2 to approximately 4.5, approximately 2 to approximately 4.4, approximately 2 to approximately 4.2, or approximately 2 to approximately 4. When the polydispersity index of the adhesive composition is within the above ranges, the stability of the adhesive 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 4.5, less than 4.4, less than 4.2, less than 4, less than 3.8, less than 3.6, less than 3.5, less than 3.4, less than 3.2, less than 3, less than 2.8, less than 2.6, less than 2.5, less than 2.4, less than 2.2, less than 2, less than 1.8, less than 1.6, less than 1.5, 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 1.5, greater than 1.6, greater than 1.8, greater than 2, greater than 2.2, greater than 2.4, greater than 2.5, greater than 2.6, greater than 2.8, greater than 3, greater than 3.2, greater than 3.4, greater than 3.5, greater than 3.6, greater than 3.8, greater than 4, greater than 4.2, greater than 4.4, greater than 4.5, greater than 4.6, or greater than 4.8.

[0158] The binder composition of the present invention exhibits strong adhesion to the current collector. Good adhesion strength of the binder composition to the current collector is important because it promotes the adhesion of the electrode layer to the current collector during the manufacture of the battery electrode, prevents its separation, and enhances the mechanical stability of the electrode. In some embodiments, the adhesion strength between the binder composition and the current collector is about 1 N / cm to about 10 N / cm, about 1.5 N / cm to about 10 N / cm, about 2 N / cm to about 10 N / cm, about 2.5 N / cm to about 10 N / cm, about 3 N / cm to about 10 N / cm, about 3.5 N / cm to about 10 N / cm, about 4 N / cm to about 10 N / cm, about 4.5 N / cm to about 10 N / cm, about 5 N / cm, etc. Approximately 10 N / cm, approximately 5.5 N / cm to approximately 10 N / cm, approximately 6 N / cm to approximately 10 N / cm, approximately 6.5 N / cm to approximately 10 N / cm, approximately 7 N / cm to approximately 10 N / cm, approximately 7.5 N / cm to approximately 10 N / cm, approximately 1 N / cm to approximately 8 N / cm, approximately 1.5 N / cm to approximately 8 N / cm, approximately 2 N / cm to approximately 8 N / cm, approximately 2.5 N / cm to approximately 8 N / cm, approximately 3 N / cm to Approximately 8 N / cm, approximately 3.5 N / cm to approximately 8 N / cm, approximately 4 N / cm to approximately 8 N / cm, approximately 4.5 N / cm to approximately 8 N / cm, approximately 5 N / cm to approximately 8 N / cm, approximately 5.5 N / cm to approximately 8 N / cm, approximately 6 N / cm to approximately 8 N / cm, approximately 2 N / cm to approximately 6.5 N / cm, approximately 2.5 N / cm to approximately 6.5 N / cm, approximately 3 N / cm to approximately 6.5 N / cm, approximately 3.5 N / cm to approximately 6. 5 N / cm, about 4 N / cm to about 6.5 N / cm, about 4.5 N / cm to about 6.5 N / cm, about 5 N / cm to about 6.5 N / cm, about 2 N / cm to about 5 N / cm, about 2.5 N / cm to about 5 N / cm, about 3 N / cm to about 5 N / cm, about 3.5 N / cm to about 5 N / cm, about 2 N / cm to about 4 N / cm, about 2.5 N / cm to about 4 N / cm, or about 3 N / cm to about 4 N / cm.

[0159] In some embodiments, the adhesion strength between the adhesive composition and the current collector is less than 10 N / cm, less than 9.5 N / cm, less than 9 N / cm, less than 8.5 N / cm, less than 8 N / cm, less than 7.5 N / cm, less than 7 N / cm, less than 6.5 N / cm, less than 6 N / cm, less than 5.5 N / cm, less than 5 N / cm, less than 4.5 N / cm, less than 4 N / cm, less than 3.5 N / cm, less than 3 N / cm, less than 2.5 N / cm, less than 2 N / cm, or less than 1.5 N / cm. In some embodiments, the adhesion strength between the adhesive composition and the current collector is greater than 1 N / cm, greater than 1.5 N / cm, greater than 2 N / cm, greater than 2.5 N / cm, greater than 3 N / cm, greater than 3.5 N / cm, greater than 4 N / cm, greater than 4.5 N / cm, greater than 5 N / cm, greater than 5.5 N / cm, greater than 6 N / cm, greater than 6.5 N / cm, greater than 7 N / cm, greater than 7.5 N / cm, greater than 8 N / cm, greater than 8.5 N / cm, greater than 9 N / cm, or greater than 9.5 N / cm.

[0160] On the other hand, this document provides 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 some embodiments, the electrode further comprises a conductive agent.

[0161] In some embodiments, the electrode active material is a cathode active material, wherein the cathode active material is selected from LiCoO2, LiNiO2, LiNi x Mn y O2, Li 1+z Ni x Mn y Co 1-x-y O2, LiNi x Co y Al z The group consisting of O2, LiV2O5, LiTiS2, LiMoS2, LiMnO2, LiCrO2, LiMn2O4, Li2MnO3, LiFeO2, LiFePO4, and combinations thereof, wherein each x is independently 0.2 to 0.9; each y is independently 0.1 to 0.45; and each z is independently 0 to 0.2. In some embodiments, the cathode active material is selected from LiCoO2, LiNiO2, LiNi x Mn y O2, Li 1+z Ni x Mn y Co 1-x-y O2(NMC), LiNi x Co y Al zThe group consisting of O2, LiV2O5, LiTiS2, LiMoS2, LiMnO2, LiCrO2, LiMn2O4, LiFeO2, LiFePO4, and combinations thereof, wherein each x is independently 0.4 to 0.6; each y is independently 0.2 to 0.4; and each z is independently 0 to 0.1. In other embodiments, the cathode active material is not LiCoO2, LiNiO2, LiV2O5, LiTiS2, LiMoS2, LiMnO2, LiCrO2, LiMn2O4, LiFeO2, or LiFePO4. In a further embodiment, the cathode active material is not LiNi x Mn y O2, Li 1+z Ni x Mn y Co 1-x-y O2 or LiNi x Co y Al z O2, wherein each x is independently 0.2 to 0.9; each y is independently 0.1 to 0.45; and each z is independently 0 to 0.2. In some embodiments, the cathode active material is Li. 1+x Ni a Mn b Co c Al (1-a-b-c) O2; where -0.2≤x≤0.2, 0≤a<1, 0≤b<1, 0≤c<1 and a+b+c≤1. In some embodiments, the cathode active material has the general formula Li 1+ x Ni a Mn b Co c Al (1-a-b-c) O2, where 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 some 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 some embodiments, the dopant is not Al, Sn, or Zr.

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

[0164] In other embodiments, the cathode active material is not LiCoO2, LiNiO2, LiMnO2, LiMn2O4, or Li2MnO3. In a further embodiment, the cathode active material is not LiNiO2. 0.33 Mn 0.33 Co 0.33 O2, LiNi 0.4 Mn 0.4 Co 0.2 O2, LiNi 0.5 Mn 0.3 Co 0.2 O2, LiNi 0.6 Mn 0.2 Co 0.2 O2, LiNi 0.7 Mn 0.15 Co 0.15 O2, LiNi0.8 Mn 0.1 Co 0.1 O2, LiNi 0.92 Mn 0.04 Co 0.04 O2 or LiNi 0.8 Co 0.15 Al 0.05 O2.

[0165] In some embodiments, the cathode active material comprises, or is itself, a core-shell composite having a core-shell structure, wherein the core and shell each independently comprise a lithium transition metal oxide selected from Li. 1+x Ni a Mn b Co c Al (1-a-b-c) O2, LiCoO2, LiNiO2, LiMnO2, LiMn2O4, Li2MnO3, LiCrO2, Li4Ti5O 12 The group consisting of LiV₂O₅, LiTiS₂, LiMoS₂, and combinations thereof, wherein -0.2 ≤ x ≤ 0.2, 0 ≤ a < 1, 0 ≤ b < 1, 0 ≤ c < 1, and a + b + c ≤ 1. In other embodiments, the core and shell each independently comprise two or more lithium transition metal oxides. In some embodiments, one of the core or shell comprises only one lithium transition metal oxide, while the other comprises two or more lithium transition metal oxides. The lithium transition metal oxides in the core and shell may be the same, different, or partially different. In some embodiments, the two or more lithium transition metal oxides are uniformly distributed in the core. In some embodiments, the two or more lithium transition metal oxides are not uniformly distributed in 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 in the core and 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 some embodiments, the core and shell each independently contain two or more doped lithium transition metal oxides. In some embodiments, the two or more doped lithium transition metal oxides are uniformly distributed on the core and / or shell. In some embodiments, the two or more doped lithium transition metal oxides are non-uniformly distributed on the core and / or shell.

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

[0168] In some embodiments, the diameter of the core is about 1 μm to about 15 μm, about 3 μm to about 15 μm, about 3 μm to about 10 μm, about 5 μm to about 10 μm, about 5 μm to about 45 μm, about 5 μm to about 35 μm, about 5 μm to about 25 μm, about 10 μm to about 45 μm, about 10 μm to about 40 μm, about 10 μm to about 35 μm, about 10 μm to about 25 μm, about 15 μm to about 45 μm, about 15 μm to about 30 μm, about 15 μm to about 25 μm, about 20 μm to about 35 μm, or about 20 μm to about 30 μm. In some embodiments, the shell thickness is about 1 μm to about 45 μm, about 1 μm to about 35 μm, about 1 μm to about 25 μm, about 1 μm to about 15 μm, about 1 μm to about 10 μm, about 1 μm to about 5 μm, about 3 μm to about 15 μm, about 3 μm to about 10 μm, about 5 μm to about 10 μm, about 10 μm to about 35 μm, about 10 μm to about 20 μm, about 15 μm to about 30 μm, about 15 μm to about 25 μm, or about 20 μm to about 35 μm. In some embodiments, the core-to-shell diameter or thickness ratio is in the range of 15:85 to 85:15, 25:75 to 75:25, 30:70 to 70:30, or 40:60 to 60:40. In some implementations, 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] A current collector collects electrons generated by the electrochemical reaction of a cathode active material, or provides electrons required for the electrochemical reaction. In some embodiments, the current collector may be in the form of a foil, sheet, or film. In some embodiments, the current collector is stainless steel, titanium, nickel, aluminum, copper, or an alloy thereof, or a conductive resin. In some embodiments, the current collector has a two-layer structure comprising an outer layer and an inner layer, wherein the outer layer comprises a conductive material, and the inner layer comprises an insulating material or another conductive material; for example, aluminum coated with a conductive resin layer or a polymer insulating material coated with an aluminum film. In some embodiments, the current collector has a three-layer structure comprising an outer layer, an intermediate layer, and an inner layer, wherein the outer and inner layers comprise conductive materials, and the intermediate layer comprises an insulating material or another conductive material; for example, a plastic substrate coated with a metal film on both sides. In some embodiments, each of the outer, intermediate, and inner layers is independently stainless steel, titanium, nickel, aluminum, copper, or an alloy thereof, or a conductive resin. In some embodiments, the insulating material is a polymeric material selected from the group consisting of polycarbonate, polyacrylate, polyacrylonitrile, polyester, polyamide, polystyrene, polyurethane, epoxy resin, poly(acrylonitrile butadiene styrene), polyimide, polyolefin, polyethylene, polypropylene, polyphenylene sulfide, poly(vinyl ester), polyvinyl chloride, polyether, polyphenylene ether, cellulose polymers, and combinations thereof. In some embodiments, the current collector has a structure of three or more layers. In some embodiments, the current collector is coated with a protective coating. In some embodiments, the protective coating comprises a carbon-containing material. In some embodiments, the current collector is not coated with a protective coating.

[0170] The thickness of the current collector affects its volume occupied within the battery, and thus the battery's energy density. In some embodiments, the current collector has a thickness of about 5 μm to about 30 μm. In other embodiments, the current collector has a thickness of about 5 μm to about 20 μm, about 5 μm to about 15 μm, about 10 μm to about 30 μm, about 10 μm to about 25 μm, or about 10 μm to about 20 μm.

[0171] In some embodiments, the current collector has a thickness of less than 30 μm, less than 28 μm, less than 26 μm, less than 24 μm, less than 22 μm, less than 20 μm, less than 18 μm, less than 16 μm, less than 14 μm, less than 12 μm, less than 10 μm, less than 8 μm, or less than 6 μm. In some embodiments, the current collector has a thickness of 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] Conductive agents are used to enhance the conductivity of electrodes. Any suitable material can be used as a 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 nanosheets, carbon fibers, carbon nanofibers, graphitized carbon sheets, carbon nanotubes, activated carbon, Super P, KS6, vapor-grown carbon fibers (VGCF), mesoporous carbon, and combinations thereof.

[0173] Furthermore, the cathode prepared using the binder composition of the present invention exhibits strong adhesion of the electrode layer to the current collector. Good peel strength of the electrode layer to the current collector is important because it prevents electrode delamination or separation, which would significantly affect the mechanical stability of the electrode and the cycle life of the battery. Therefore, the electrode should have sufficient peel strength to withstand the harshness of the battery manufacturing process.

[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, and about 1.5 N / cm. The range is approximately 2.5 N / cm, approximately 1.5 N / cm to approximately 2.0 N / cm, approximately 1.8 N / cm to approximately 3.0 N / cm, approximately 1.8 N / cm to approximately 2.5 N / cm, approximately 2.0 N / cm to approximately 6.0 N / cm, approximately 2.0 N / cm to approximately 5.0 N / cm, approximately 2.0 N / cm to approximately 3.0 N / cm, approximately 2.0 N / cm to approximately 2.5 N / cm, approximately 2.2 N / cm to approximately 3.0 N / cm, approximately 2.5 N / cm to approximately 3.0 N / cm, approximately 3.0 N / cm to approximately 8.0 N / cm, approximately 3.0 N / cm to approximately 6.0 N / cm, or approximately 4.0 N / cm to approximately 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 higher, 1.2 N / cm or higher, 1.5 N / cm or higher, 2.0 N / cm or higher, 2.2 N / cm or higher, 2.5 N / cm or higher, 3.0 N / cm or higher, 3.5 N / cm or higher, 4.5 N / cm or higher, 5.0 N / cm or higher, or 5.5 N / cm or higher. 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] When a binder composition comes into contact with an electrolyte, it may absorb some of the electrolyte and swell. The degree of swelling of the binder composition due to electrolyte absorption provides insight into the crystallinity of the binder composition, how it interacts with the electrolyte, and its flexibility. On the one hand, highly crystalline binder compositions exhibit low swelling behavior and can act as a barrier to electrolyte solvent ingress. This results in shorter ion transport paths, reducing internal resistance, and, more importantly, altering the mechanical properties of the swollen polymer, which is crucial for stable battery performance. On the other hand, low-crystallinity binder compositions have a larger number of amorphous regions, where a greater amount of electrolyte can permeate into the binder composition to ensure good ion transport without causing the binder composition to break upon swelling. The semi-crystalline binder compositions disclosed herein benefit from both of these influencing factors and therefore exhibit excellent electrochemical performance.

[0177] In some embodiments, the electrolyte swelling rate of the adhesive composition is about 1% to about 15% by weight, 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 7% to about 15%, about 7.5% to about 15%, about 8% to about 15%, about 8.5% to about 15%, about 9% to about 15%, about 9.5% to about 15%, about 10% to about 15%, about 3% to about 10%, about 4% to about 10%, about 5% to about 10%, about 6% to about 10%, about 7% to about 10%, about 5% to about 9%, about 6% to about 9%, about 7% to about 9%, about 7.5% to about 9%, or about 8% to about 9%.

[0178] In some embodiments, the electrolyte swelling rate of the adhesive composition is less than 15%, less than 14%, less than 13%, less than 12%, less than 11%, less than 10%, less than 9.5%, less than 9%, less than 8.5%, less than 8%, less than 7.5%, less than 7%, less than 6%, less than 5%, less than 4%, less than 3%, or less than 2% by weight. In some embodiments, the electrolyte swelling rate of the adhesive composition is greater than 1%, greater than 2%, greater than 3%, greater than 4%, greater than 5%, greater than 6%, greater than 7%, greater than 7.5%, greater than 8%, greater than 8.5%, greater than 9%, greater than 9.5%, greater than 10%, greater than 11%, greater than 12%, greater than 13%, or greater than 14% by weight.

[0179] The adhesive composition disclosed herein has the advantage of being able to use aqueous solvents in its manufacturing process, thereby saving process time and facilities, while improving safety by avoiding hazardous organic solvents that require handling or recycling. Furthermore, costs are reduced due to the simplified overall process. Therefore, this adhesive composition is particularly suitable for large-scale manufacturing due to its low-cost and easy-to-handle manufacturing method.

[0180] The following embodiments are provided to illustrate implementations of the invention, but are not intended to limit the invention to the specific embodiments listed. Unless otherwise stated, all parts and percentages are by weight. All values ​​are approximate. When numerical ranges are given, it should be understood that implementations outside the stated ranges still fall within the scope of the invention. Specific details described in the various embodiments should not be construed as essential features of the invention.

[0181] Example

[0182] The pH value of the adhesive composition was measured using an electrode-type pH meter (ION 2700, Eutech Instruments).

[0183] The viscosity of the binder composition was measured at 25°C using a rotational viscometer (NDJ-5S, from Shanghai JT Electronics Technology Co., Ltd., China) at a rotational speed of 30 rpm using rotor No. 3.

[0184] The adhesive strength of a dried adhesive composition layer was measured using a tensile testing machine (DZ-106A, from Dongguan Zonhow Test Equipment Co., Ltd., China). This test measures the average force, expressed in Newtons (N), required to peel the adhesive composition layer from the current collector at a 180° angle. The average roughness depth (R) of the current collector is also measured. zThe thickness is 2 μm. The adhesive composition is coated onto the current collector and dried to obtain an adhesive composition layer with a thickness of 10 μm to 12 μm. The coated current collector is then placed in an environment with a constant temperature of 25°C and a relative humidity of 50% to 60% for 30 minutes. A 18 mm wide and 20 mm long strip of adhesive tape (3M; USA; model 810) is adhered to the surface of the adhesive composition layer. The adhesive composition strip is clamped in a testing machine, and the tape is folded back 180°, placed in a movable jaw, and pulled at a peel speed of 300 mm / min at room temperature. The maximum peel force measured is taken as the adhesive strength. The measurement is repeated three times and the average value is taken.

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

[0186]

[0187] The weight-average molecular weight and number-average molecular weight of the adhesive composition were determined by gel permeation chromatography (GPC). First, the adhesive composition was dissolved in dimethylformamide at room temperature. Once the adhesive composition was completely dissolved, the solution was slowly filtered through a 0.45 μm pore size filter to prepare the test sample. A calibration curve was prepared using polystyrene standards, and the weight-average and number-average molecular weights of the adhesive composition were calculated from the curve. The obtained test sample was analyzed using an Agilent PLgel 5 μm MIXED-C column. The flow rate was 1 mL / min, and the sample weight was 2 mg. A Waters 2414 refractive index (RI) detector was used, and the detection temperature was 35 °C.

[0188] Example 1

[0189] A) Preparation of adhesive composition

[0190] Add 11.90 g of sodium hydroxide (NaOH) to a round-bottom flask containing 380 g of distilled water. Stir the mixture at 80 rpm for 30 minutes to obtain a first suspension.

[0191] Add 24.78g of acrylic acid to the first suspension. Stir the mixture further at 80 rpm for 30 minutes to obtain the second suspension.

[0192] 7.19 g of acrylamide was dissolved in 10 g of deionized water to form an acrylamide solution. Then, all of the acrylamide solution was added to the second suspension. The mixture was further heated to 55°C and stirred at 80 rpm for 45 minutes to obtain a third suspension.

[0193] Add 30.06 g of acrylonitrile to the third suspension. Stir the mixture further at 80 rpm for 10 minutes to obtain the fourth suspension.

[0194] Then, 0.03 g of water-soluble free radical initiator (ammonium persulfate, APS; from Aladdin Industrial Co., Ltd., China) was dissolved in 3 g of deionized water, and 0.015 g of reducing agent (sodium bisulfite; from Tianjin Damao Chemical Reagent Factory, China) was dissolved in 1.5 g of deionized water. All APS and sodium bisulfite solutions were added to the fourth suspension. The mixture was stirred at 55 °C and 200 rpm for 24 h to obtain the fifth suspension.

[0195] After complete reaction, the temperature of the fifth suspension was lowered to 25°C. 3.72 g of NaOH was dissolved in 400 g of deionized water to form a sodium hydroxide solution. Subsequently, all the sodium hydroxide solution was added dropwise to the fifth suspension over 1 hour to adjust the pH to 7.3 to form the sixth suspension. The sixth suspension was filtered through a 200 μm nylon mesh to form the binder composition. The weight-average molecular weight, number-average molecular weight, and polydispersity index of the binder composition were 128,500 g / mol, 57,400 g / mol, and 2.24, respectively. The pH and solids content of the binder composition were 7.6 and 8.31 wt.%, respectively. The components of the binder composition of Example 1 and their respective proportions are shown in Table 1 below. The viscosity and adhesive strength of the binder composition of Example 1 were measured and are shown in Table 1 below.

[0196] By varying the polymerization conditions, two additional iterations of the binder composition were prepared. In the first iteration, the binder composition had a weight-average molecular weight, number-average molecular weight, and polydispersity index of 79,500 g / mol, 36,200 g / mol, and 2.20, respectively, while the viscosity was 3,000 mPa·s. In the second iteration, the binder composition had a weight-average molecular weight, number-average molecular weight, and polydispersity index of 257,000 g / mol, 134,300 g / mol, and 1.91, respectively, while the viscosity was 30,000 mPa·s. In both iterations, the electrode paste prepared with the binder composition exhibited poor processability, preventing the production of usable batteries.

[0197] B) Cathode Preparation

[0198] A first mixture was prepared by dispersing 12 g of conductive agent (SuperP; from Timcal Ltd, Bodio, Switzerland) and 100 g of binder composition (8.31 wt.% solids content) in 74 g of deionized water while stirring with a top-mounted stirrer (R20, IKA). After addition, the first mixture was further stirred at 1,200 rpm for approximately 30 minutes at 25°C.

[0199] Then, at 25°C, 276 g of NMC811 (from Shandong Tianjiao New Energy Co., Ltd., China) was added to the first mixture while stirring with a top-mounted agitator to prepare the second mixture. The second mixture was then degassed at approximately 10 kPa for 1 hour. The second mixture was then further stirred at 1,200 rpm at 25°C for approximately 60 minutes to form a homogenized cathode slurry.

[0200] Homogenized cathode paste was coated onto both sides of a 16 μm thick aluminum foil, serving as the current collector, using a blade coater with a gap width of 120 μm. An 80 μm layer of the coated paste on the aluminum foil was dried in an electrically heated oven at 85°C to form the cathode electrode layer. The drying time was approximately 120 minutes. The electrode was then pressed to reduce the thickness of the cathode electrode layer to 34 μm. The surface density of the cathode electrode layer on the current collector was 16.00 mg / cm³. 2 .

[0201] C) Assembly of button batteries

[0202] CR2032 button-type Li batteries were assembled in an argon-filled glove box. A 500 μm thick lithium metal foil was used as the anode. The cathode and anode were cut into disc-shaped positive and negative electrodes, and the electrode elements were assembled by alternately stacking the cathode and anode electrodes and then housing them in a CR2032 type stainless steel casing. The cathode and anode were separated by a separator. The separator was a ceramic-coated nonwoven fabric (MPM, Japan) microporous membrane with a thickness of approximately 25 μm. The electrode elements were then dried in a box-type resistance furnace (DZF-6020, from Shenzhen Kejing Star Technology Co., Ltd., China) under vacuum at 105 °C for approximately 16 hours.

[0203] In a high-purity argon atmosphere with humidity and oxygen content both less than 3 ppm, the electrolyte is injected into the casing containing the electrodes. The electrolyte is a solution containing LiPF6 (1M) in a 1:1:1 volume ratio mixture of ethylene carbonate (EC), ethyl methyl carbonate (EMC), and dimethyl carbonate (DMC). After the electrolyte is injected, the button cell is vacuum-sealed and then mechanically stamped using a standard circular stamping tool.

[0204] D) Electrochemical Measurement

[0205] The button cell was analyzed in constant current mode using a multichannel battery tester (BTS-4008-5V10mA, from Xinwei Electronics Co., Ltd., China). After activation at C / 20, it was charged and discharged at a rate of C / 2. The discharge capacity was obtained by charge / discharge cycling the battery at a current density of C / 2 between 3.0V and 4.3V at 25°C. The electrochemical performance of the button cell of Example 1 was tested and is shown in Table 1 below.

[0206] Example 2

[0207] The binder composition was prepared in the same manner as in Example 1, except that 11.09 g of NaOH was added when preparing the first suspension, 23.32 g of acrylic acid was added when preparing the second suspension, 12.22 g of acrylamide was added when preparing the third suspension, and 27.37 g of acrylonitrile was added when preparing the fourth suspension. The weight-average molecular weight, number-average molecular weight, and polydispersity index of the binder composition were 168,100 g / mol, 72,500 g / mol, and 2.32, respectively. The pH and solids content of the binder composition were 8.3 and 8.75 wt.%, respectively.

[0208] Example 3

[0209] The binder composition was prepared in the same manner as in Example 1, except that 16.35 g of NaOH was added when preparing the first suspension, 32.80 g of acrylic acid was added when preparing the second suspension, 4.31 g of acrylamide was added when preparing the third suspension, and 26.30 g of acrylonitrile was added when preparing the fourth suspension. The weight-average molecular weight, number-average molecular weight, and polydispersity index of the binder composition were 127,700 g / mol, 56,500 g / mol, and 2.26, respectively. The pH and solids content of the binder composition were 8.2 and 6.01 wt.%, respectively.

[0210] Example 4

[0211] The binder composition was prepared in the same manner as in Example 1, except that 8.26 g of NaOH was added when preparing the first suspension, 18.22 g of acrylic acid was added when preparing the second suspension, 13.66 g of acrylamide was added when preparing the third suspension, and 30.06 g of acrylonitrile was added when preparing the fourth suspension. The weight-average molecular weight, number-average molecular weight, and polydispersity index of the binder composition were 125,000 g / mol, 55,400 g / mol, and 2.26, respectively. The pH and solids content of the binder composition were 7.8 and 7.69 wt.%, respectively.

[0212] Example 5

[0213] The binder composition was prepared in the same manner as in Example 1, except that 10.68 g of NaOH was added when preparing the first suspension, 22.60 g of acrylic acid was added when preparing the second suspension, 16.54 g of acrylamide was added when preparing the third suspension, and 24.69 g of acrylonitrile was added when preparing the fourth suspension. The pH and solids content of the binder composition were 7.9 and 8.23 ​​wt.%, respectively.

[0214] Example 6

[0215] The binder composition was prepared in the same manner as in Example 1, except that 10.28 g of NaOH was added when preparing the first suspension, 21.87 g of acrylic acid was added when preparing the second suspension, 5.03 g of acrylamide was added when preparing the third suspension, and 33.81 g of acrylonitrile was added when preparing the fourth suspension. The pH and solids content of the binder composition were 7.6 and 8.24 wt.%, respectively.

[0216] Example 7

[0217] The binder composition was prepared in the same manner as in Example 1, except that 14.73 g of NaOH was added when preparing the first suspension, 29.88 g of acrylic acid was added when preparing the second suspension, 8.63 g of acrylamide was added when preparing the third suspension, and 25.23 g of acrylonitrile was added when preparing the fourth suspension. The weight-average molecular weight, number-average molecular weight, and polydispersity index of the binder composition were 107,700 g / mol, 42,400 g / mol, and 2.54, respectively. The pH and solids content of the binder composition were 7.8 and 8.71 wt.%, respectively.

[0218] Example 8

[0219] The binder composition was prepared in the same manner as in Example 1, except that 9.87 g of NaOH was added when preparing the first suspension, 21.14 g of acrylic acid was added when preparing the second suspension, 7.91 g of acrylamide was added when preparing the third suspension, and 32.20 g of acrylonitrile was added when preparing the fourth suspension. The weight-average molecular weight, number-average molecular weight, and polydispersity index of the binder composition were 198,100 g / mol, 96,500 g / mol, and 2.05, respectively. The pH and solids content of the binder composition were 7.9 and 7.81 wt.%, respectively.

[0220] Example 9

[0221] The binder composition was prepared in the same manner as in Example 1, except that 8.66 g of NaOH was added when preparing the first suspension, 18.95 g of acrylic acid was added when preparing the second suspension, 17.26 g of acrylamide was added when preparing the third suspension, and 26.84 g of acrylonitrile was added when preparing the fourth suspension. The pH and solids content of the binder composition were 7.9 and 7.87 wt.%, respectively.

[0222] Example 10

[0223] The binder composition was prepared in the same manner as in Example 1, except that 13.52 g of NaOH was added when preparing the first suspension, 27.70 g of acrylic acid was added when preparing the second suspension, 5.75 g of acrylamide was added when preparing the third suspension, and 28.98 g of acrylonitrile was added when preparing the fourth suspension. The pH and solids content of the binder composition were 7.7 and 8.35 wt.%, respectively.

[0224] Comparative Example 1

[0225] The binder composition was prepared in the same manner as in Example 1, except that 6.64 g of NaOH was added when preparing the first suspension, 15.31 g of acrylic acid was added when preparing the second suspension, 5.03 g of acrylamide was added when preparing the third suspension, and 38.64 g of acrylonitrile was added when preparing the fourth suspension. The pH and solids content of the binder composition were 7.7 and 7.32 wt.%, respectively.

[0226] Comparative Example 2

[0227] The binder composition was prepared in the same manner as in Example 1, except that 15.13 g of NaOH was added when preparing the first suspension, 30.61 g of acrylic acid was added when preparing the second suspension, 17.26 g of acrylamide was added when preparing the third suspension, and 18.25 g of acrylonitrile was added when preparing the fourth suspension. The pH and solids content of the binder composition were 7.4 and 8.92 wt.%, respectively.

[0228] Comparative Example 3

[0229] The binder composition was prepared in the same manner as in Example 1, except that 6.64 g of NaOH was added when preparing the first suspension, 15.31 g of acrylic acid was added when preparing the second suspension, 23.73 g of acrylamide was added when preparing the third suspension, and 24.69 g of acrylonitrile was added when preparing the fourth suspension. The pH and solids content of the binder composition were 7.7 and 8.01 wt.%, respectively.

[0230] Comparative Example 4

[0231] The binder composition was prepared in the same manner as in Example 1, except that 15.54 g of NaOH was added when preparing the first suspension, 31.34 g of acrylic acid was added when preparing the second suspension, no acrylamide was added when preparing the third suspension, and 30.59 g of acrylonitrile was added when preparing the fourth suspension. The pH and solids content of the binder composition were 7.9 and 8.24 wt.%, respectively.

[0232] Comparative Example 5

[0233] The binder composition was prepared in the same manner as in Example 1, except that 19.58 g of NaOH was added when preparing the first suspension, 38.63 g of acrylic acid was added when preparing the second suspension, 9.35 g of acrylamide was added when preparing the third suspension, and 18.25 g of acrylonitrile was added when preparing the fourth suspension. The pH and solids content of the binder composition were 7.5 and 9.85 wt.%, respectively.

[0234] Comparative Example 6

[0235] The binder composition was prepared in the same manner as in Example 1, except that 2.19 g of NaOH was added when preparing the first suspension, 7.29 g of acrylic acid was added when preparing the second suspension, 17.97 g of acrylamide was added when preparing the third suspension, and 34.89 g of acrylonitrile was added when preparing the fourth suspension. The pH and solids content of the binder composition were 7.2 and 8.70 wt.%, respectively.

[0236] Preparation of the positive electrode in Examples 2-10 and Comparative Examples 1-6

[0237] The positive electrodes of Examples 2-10 and Comparative Examples 1-6 were prepared in the same manner as in Example 1, except that the positive electrodes of each example were prepared using the binder composition prepared in each example.

[0238] Assembly of button batteries in Examples 2-10 and Comparative Examples 1-6

[0239] The button batteries of Examples 2-10 and Comparative Examples 1-6 were assembled in the same manner as in Example 1, except that the positive electrode prepared in each example was used to assemble the button battery of that example.

[0240] Electrochemical measurements of Examples 2-10 and Comparative Examples 1-6

[0241] The electrochemical performance of the button batteries of Examples 2-10 and Comparative Examples 1-6 was measured in the same manner as in Example 1, and the test results are shown in Table 1 below.

[0242] Although the invention has been described in conjunction with a limited number of embodiments, specific features of one embodiment should not limit other embodiments of the invention. In some embodiments, the method may include multiple steps not mentioned herein. In other embodiments, the method does not include or substantially does not contain any steps not listed herein. Variations and modifications based on the described embodiments exist. The appended claims are intended to cover all such variations and modifications that fall within the scope of the invention.

[0243]

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 monomer containing a carboxylic acid group; a structural unit (b) derived from a monomer containing an amide group; and a structural unit (c) derived from a monomer containing a nitrile group; wherein, based on the total molar number of monomer units in the copolymer in the binder composition, the structural unit (a) in the copolymer accounts for 15% to 50% by molar, wherein, based on the total molar number of monomer units in the copolymer in the binder composition, the structural unit (b) in the copolymer accounts for 4% to 25% by molar, and the structural unit (c) in the copolymer accounts for 46% to 65% by molar, wherein the sum of structural units (a) and structural units (b) accounts for 35% to 54% by molar.

2. The adhesive composition according to claim 1, wherein the monomer containing a carboxylic acid group is selected from acrylic acid, methacrylic acid, crotonic acid, 2-butylcrotonic acid, cinnamic acid, maleic acid, maleic anhydride, fumaric acid, itaconic acid, itaconic anhydride, 4,4-dimethylitaconic acid, 2-ethylacrylic acid, isocrotonic acid, cis-2-pentenoic acid, trans-2-pentenoic acid, angelic acid, tigric acid, 3,3-dimethylacrylic acid, 3-propylacrylic acid, trans-2-methyl-3-ethylacrylic acid, cis-2-methyl-3-ethylacrylic acid, etc. Acrylic acid, 3-isopropylacrylic acid, trans-3-methyl-3-ethylacrylic acid, cis-3-methyl-3-ethylacrylic acid, 2-isopropylacrylic acid, trimethicone, 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-hexyl Acrylic 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-octenic acid, cis-2-octenic acid, trans-2-decenoic acid, α-ethyl The group consisting of acyloxyacrylic acid, β-trans-aryloxyacrylic acid, α-chloro-β-E-methoxyacrylic acid, methylmaleic acid, dimethylmaleic acid, phenylmaleic acid, bromomaleic acid, chloromaleic acid, dichloromaleic acid, fluoromaleic acid, difluoromaleic acid, nonyl hydrogen maleate, decyl hydrogen maleate, dodecyl hydrogen maleate, octadecyl hydrogen maleate, hydrofluoroalkyl maleate, methylmaleic anhydride, dimethylmaleic anhydride, acrylic anhydride, methacrylic anhydride, methacryloyl chloride, methacryloyl fluoride, methacryloyl bromide, and combinations thereof.

3. The adhesive composition according to claim 1, wherein the structural unit (a) in the copolymer accounts for 25% to 45% on a molar basis, based on the total molar number of monomer units in the copolymer of the adhesive composition.

4. The adhesive composition according to claim 1, wherein the monomer containing the amide group is selected from 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-hydroxymethylmethacrylamide, N-(methoxymethyl)methacrylamide, N-(ethoxy)methacrylamide, etc. The group consisting of methyl methacrylamide, N-(propoxymethyl)methacrylamide, N-(butoxymethyl)methacrylamide, N,N-dimethylmethacrylamide, N-(3-(dimethylamino)propyl)methacrylamide, N-(2-(dimethylamino)ethyl)methacrylamide, N,N-(dihydroxymethyl)methacrylamide, diacetone methacrylamide, diacetone acrylamide, methacryloylmorpholine, N-hydroxymethacrylamide, N-methoxymethylmethacrylamide, N,N'-methylenebisacrylamide, N-hydroxymethylacrylamide, and combinations thereof.

5. The adhesive composition according to claim 1, wherein, based on the total molar number of monomer units in the copolymer of the adhesive composition, the proportion of the structural unit (b) in the copolymer is more than 5% and less than 25% on a molar basis.

6. The adhesive composition according to claim 1, wherein the monomer containing the nitrile group is selected from the group consisting of acrylonitrile, α-haloacrylonitrile, α-alkylacrylonitrile, α-methoxyacrylonitrile, 3-methoxyacrylonitrile, 3-ethoxyacrylonitrile, α-acetoxyacrylonitrile, α-phenylacrylonitrile, α-tolylacrylonitrile, α-(methoxyphenyl)acrylonitrile, α-(chlorophenyl)acrylonitrile, α-(cyanophenyl)acrylonitrile, vinylidene cyanide, and combinations thereof.

7. The adhesive composition according to claim 1, wherein the monomer containing the nitrile group is selected from the group consisting of α-chloroacrylonitrile, α-bromoacrylonitrile, α-fluoroacrylonitrile, methacrylonitrile, α-ethylacrylonitrile, α-isopropylacrylonitrile, α-n-hexylacrylonitrile, and combinations thereof.

8. The adhesive composition according to claim 1, wherein the structural unit (c) in the copolymer accounts for 46% to 63% on a molar basis, based on the total molar number of monomer units in the copolymer of the adhesive composition.

9. The adhesive composition according to claim 1, wherein the dispersion medium is water.

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

11. The adhesive composition according to claim 1, wherein in the copolymer of the adhesive composition, the molar ratio of the sum of the structural unit (a) and the structural unit (b) to the structural unit (c) is 0.5 to 1.

2.

12. The adhesive composition of claim 1, wherein the pH of the adhesive composition is 7 to 10.

13. The adhesive composition according to claim 1, wherein the viscosity of the adhesive composition is from 5,000 mPa·s to 25,000 mPa·s.

14. The adhesive composition according to claim 1, wherein the electrolyte swelling rate of the adhesive composition is 1% to 15%.

15. The adhesive composition of claim 1, wherein the solid content of the adhesive composition is from 1% to 20% by weight, based on the total weight of the adhesive composition.

16. The adhesive composition of claim 1, wherein the number average molecular weight of the copolymer in the adhesive composition is from 30,000 g / mol to 100,000 g / mol.

17. The adhesive composition of claim 1, wherein the copolymer in the adhesive composition has a weight-average molecular weight of 100,000 g / mol to 200,000 g / mol.

18. An electrode for a secondary battery, comprising a current collector and an electrode layer coated on the current collector, wherein the electrode layer comprises an electrode active material and a binder composition according to claim 1.

19. The electrode of claim 18, wherein the adhesion strength between the binder composition and the current collector is from 1 N / cm to 10 N / cm.

20. The electrode of claim 18, wherein 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.

21. The electrode of claim 18, wherein the electrode layer further comprises a conductive agent.

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