Method for manufacturing electrode for secondary battery

Abstract

A method for manufacturing an electrode using an electrode material mixture is disclosed, in which a binder material, an electrode active material (and a conductive agent, if any) are pre-mixed in a dry state substantially free of liquid, and then water is added to the pre-mix to form an electrode material mixture. The binder material is a hydrophilic copolymer that can be fibrillated under shear force, and includes hydrophilic structural units and non-hydrophilic structural units, wherein the proportion of the hydrophilic structural units in the copolymer is about 60% to about 90% by mole, based on the total number of moles of monomer units in the copolymer, and the weight average molecular weight is about 400,000 g / mol to about 700,000 g / mol. The liquid content of the electrode material mixture is about 5% to about 22% by weight, based on the total weight of the electrode material mixture. When the electrode material mixture is manufactured using the method of the present invention, the electrode material mixture and the electrode layer obtained after coating have good dispersibility, and the electrode layer has strong adhesion to the current collector. Therefore, a thicker electrode layer can be prepared, and a battery including the electrode layer has a higher energy density.

Description

Technical Field

[0001] This invention relates to the field of batteries. More specifically, this invention relates to methods for manufacturing electrodes that can be used in lithium-ion batteries and other metal-ion batteries. Background Technology

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

[0003] Typically, lithium-ion battery electrodes comprise an electrode layer bonded to a current collector. This electrode layer consists of various electrode components, such as electrode active materials, conductive materials, and a binder composition. The binder material provides good electrochemical stability to the electrode layer, holds the electrode components together, and adheres them to the current collector. Electrode slurries are commonly used to prepare the electrode layer, where the solvent suspends or dissolves the various electrode components to facilitate processing and coating onto the current collector. Polyvinylidene fluoride (PVDF) is one of the most commonly used binder materials in the commercial lithium-ion battery industry, but PVDF can only dissolve in certain organic solvents such as N-methyl-2-pyrrolidone (NMP). Therefore, these organic solvents are used as solvents in electrode slurries containing PVDF. However, NMP is flammable and toxic, requiring special handling. An NMP recovery system must be included during the drying process to recover NMP vapor. This imposes high costs on the manufacturing process and requires significant investment.

[0004] Considering the drawbacks of using organic solvent-based slurries to prepare electrodes, the industry has begun to consider switching to water-based slurries, which use aqueous solvents (most commonly water). Since PVDF is insoluble in water and has poor dispersibility in water, another type of polymer that is compatible with water must be used as a binder material in water-based electrode slurries. These water-based slurries often require the addition of a large amount of solvent to ensure sufficient dispersion of the electrode components; sufficient dispersion of electrode components is a necessary condition for ensuring excellent electrode performance. However, water may cause degradation of the positive electrode active material, leading to a decrease in battery performance.

[0005] Based on the above, the industry has developed electrode material mixtures with significantly reduced liquid content. A common technique for preparing electrode layers without the use of solvents is polymer fiberization. This process involves processing a fiberizable polymer, such as PTFE (polytetrafluoroethylene), as a single component or in a compound system containing the polymer, in conjunction with other electrode components (such as conductive agents), through air jet milling, calendering, extrusion, etc. By applying shear force, the polymer undergoes fiberization and forms a network matrix. This matrix can encapsulate and support other electrode components, thus acting as a binder. US Patent Application Publication No. 10,547,057 discloses a scheme for applying polymer fiberization technology in an electrode material mixture that is essentially free of moisture: a dry powder material composed of electrode active material, conductive agent, and PTFE as a binder is propelled by compressed air and fed into the grinding chamber of an air jet mill through a nozzle. This technology demonstrates that particle collisions generate shear forces, leading to the fibrosis of polytetrafluoroethylene (PTFE). This allows the electrode active material and conductive agent to be embedded within the PTFE fibrous matrix, while the electrode active material and conductive agent particles also prevent PTFE from re-aggregating to some extent. However, PTFE exhibits strong van der Waals forces with carbon-based conductive agents, thus reducing its fibrosis effect. Furthermore, PTFE is a fluoropolymer. Even if solvents are not used in the electrode preparation process, the recovery and separation of various electrode components still require heat treatment processes that release toxic organic solvents or toxic chemicals, thus posing serious environmental problems. In addition, the equipment used to generate the high shear forces required for polymer fibrosis is energy-intensive and expensive to operate.

[0006] In light of this, the inventors, based on in-depth research into this problem, discovered a novel hydrophilic copolymer that can serve as a binder material, effectively used in electrode material mixtures with specific and reduced water solvent content, and this copolymer is easily fibrous. The copolymer itself is hydrophilic, easily recyclable, and requires no environmentally damaging treatment methods. When using this copolymer to prepare electrodes, the electrode thickness can be greater than that of electrodes made from conventional electrode mixtures, thereby increasing battery capacity. Of particular note, the inventors found that employing specific preparation methods for electrode material mixtures is crucial to ensuring the superior electrochemical performance of the resulting electrodes. Summary of the Invention

[0007] Various aspects and embodiments of the present invention can satisfy the above-mentioned needs. In one aspect, the present invention provides a method for manufacturing an electrode using an electrode material mixture, wherein the electrode material mixture comprises a copolymer as a binder material, an electrode active material, water, and a conductive agent (if any), wherein the electrode material mixture is prepared by premixing the binder material and the electrode active material (and the conductive agent, if any) in a substantially liquid-free dry state, followed by adding water to the premix to form the electrode material mixture. In some embodiments, the copolymer is inherently water-compatible, comprising hydrophilic and hydrophobic structural units, and the copolymer in the binder composition is fibrous under shear force. In some embodiments, the hydrophilic structural units account for about 60% to about 90% of the total molar number of monomer units in the copolymer. In some embodiments, the weight-average molecular weight of the copolymer is about 400,000 g / mol to about 700,000 g / mol. In some embodiments, the liquid content of the electrode material mixture is about 5% to about 22% by weight, based on the total weight of the electrode material mixture.

[0008] On the other hand, the present invention provides a particularly illustrative embodiment of the copolymer, wherein the hydrophilic structural units of the binder composition are derived from acid-containing monomers and amide-containing monomers, and the non-hydrophilic structural units of the binder composition are derived from nitrile-containing monomers. In some embodiments, based on the total molar number of monomer units in the copolymer, the proportion of monomer units derived from acid-containing monomers in the copolymer is from about 10% to about 40% by molar, while the proportion of monomer units derived from amide-containing monomers in the copolymer is from about 10% to about 55% by molar.

[0009] Because the components of the electrode material mixture are added in a specific order during manufacturing, the electrode components are well dispersed in both the electrode material mixture and the resulting electrode layer. Simultaneously, the copolymer readily undergoes fibrosis, meaning the electrode components adhere firmly to the current collector. Therefore, the increased electrode layer thickness leads to improved battery energy density. Furthermore, this copolymer can be easily recycled after battery disposal, eliminating the need for environmentally damaging treatment methods. Detailed Implementation

[0010] The term "electrode" refers to either "cathode" or "anode".

[0011] The terms "positive electrode" and "cathode" are used interchangeably. Similarly, the terms "negative electrode" and "anode" are used interchangeably.

[0012] The term "current collector" refers to any conductive substrate that is in contact with the electrode layer and is 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.

[0013] The term "electrode layer" refers to a layer containing electrochemically active material that is in contact with the current collector. In some embodiments, an electrode is formed by applying an electrode layer 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.

[0014] The term "water-compatible" for a compound, mixture of compounds, or polymer means that the compound, mixture of compounds, or polymer can be well dispersed in an aqueous solvent to form a solution or colloid.

[0015] The term "binder material" refers to a compound, mixture of compounds, or polymer used to hold materials in place and adhere them to a substrate. In some embodiments, the binder material is used to hold electrode components in place and adhere them to a conductive metal part to prepare an electrode. In some embodiments, the binder material comprises a polymer. This polymer may be referred to as a "binder polymer." In some embodiments, the binder material is used in conjunction with a liquid, collectively referred to as a "binder composition." In some embodiments, the liquid is water. In some embodiments, the binder material is in a dry state or substantially free of liquid. In other embodiments, the binder material is free of liquid.

[0016] For the purposes of this term, "dry" means that the mixture is substantially free of liquid or contains no liquid. "Substantially free of liquid" means that the liquid content of the mixture is very low. In some embodiments, "substantially free of liquid" means that, based on the total weight of the mixture, the liquid content in the mixture is less than 1%, less than 0.8%, less than 0.6%, less than 0.5%, less than 0.4%, less than 0.3%, less than 0.2%, less than 0.15%, less than 0.1%, less than 0.05%, less than 0.03%, less than 0.02%, less than 0.015%, less than 0.01%, less than 0.075%, less than 0.05%, less than 0.025%, less than 0.02%, less than 0.015%, less than 0.01%, less than 0.0075%, less than 0.005%, less than 0.0025%, less than 0.002%, less than 0.0015%, or less than 0.001%.

[0017] The term "conductive material" or "conductive agent" refers to a material with good electrical conductivity. Therefore, in the fabrication of electrodes, conductive agents are often mixed with electrode active materials to improve the electrode's conductivity. In some embodiments, the conductive agent is chemically active. In some embodiments, the conductive agent is chemically inert.

[0018] The term "electrode material mixture" refers to a mixture of materials that can be used to prepare an electrode layer. In some embodiments, the electrode material mixture comprises an electrode active material and a binder material. In some embodiments, the electrode material mixture further comprises a conductive agent. In some embodiments, the electrode material mixture further comprises a solvent, and the electrode material mixture may thus be referred to as an "electrode slurry".

[0019] For slurries, the term "aqueous" refers to a slurry whose solvent is an aqueous solvent. The term "aqueous solvent" refers to a solution whose main component is water, and which contains one or more other trace components, or a solution composed entirely of water.

[0020] The term "unsaturation" refers to a moiety that has one or more unsaturated units.

[0021] The term "alkyl" or "alkyl group" refers to a group having the general formula C n H 2n+1 The monovalent group is derived from a saturated unbranched or branched aliphatic hydrocarbon by removing a hydrogen atom, where n is an integer.

[0022] The term "cycloalkyl" or "cycloalkyl group" refers to a saturated or unsaturated cyclic non-aromatic hydrocarbon group having a monocyclic or multiple fused rings. The cycloalkyl group can be unsubstituted or substituted with one or two suitable substituents. Furthermore, cycloalkyl groups can be monocyclic or polycyclic.

[0023] The term "alkenyl" refers to a monovalent group formed by removing a hydrogen atom from any carbon atom of an unsaturated aliphatic hydrocarbon having at least one carbon-carbon double bond. Similarly, the term "alkynyl" refers to a monovalent group formed by removing a hydrogen atom from any carbon atom of an unsaturated aliphatic hydrocarbon having at least one carbon-carbon triple bond. Furthermore, the term "enynyl" refers to a monovalent group formed by removing a hydrogen atom from any carbon atom of an unsaturated aliphatic hydrocarbon having at least one carbon-carbon double bond and at least one carbon-carbon triple bond. Alkenyl, alkynyl, or enynyl unsaturated aliphatic hydrocarbons can be branched or linear.

[0024] The term "alkylene" refers to a saturated divalent hydrocarbon group derived from a straight-chain or branched saturated hydrocarbon by removing two hydrogen atoms, and may optionally be substituted with one or more substituents as described in this invention.

[0025] The term "alkoxy group" refers to an alkyl group as described above, connected to the main carbon chain via an oxygen atom. Alkoxy groups can be substituted or unsubstituted.

[0026] The term "aryl" or "aryl group" refers to an organic group derived from a monocyclic or polycyclic aromatic hydrocarbon by removing one hydrogen atom. An aryl group can be unsubstituted or substituted with one or more suitable substituents.

[0027] The term "alkylamine" refers to a group obtained by removing a hydrogen atom from a primary or secondary amine. Alkylamines include the terms "N-alkylamine" and "N,N-dialkylamine," wherein the amine group is substituted by one or two alkyl groups, respectively. Alkylamines may optionally be substituted by one or more substituents.

[0028] The term "alkathio" refers to a group containing a branched or straight-chain alkyl group attached to a divalent sulfur atom. The alkathio group may optionally be substituted with one or more substituents.

[0029] The term “heteroatom” refers to one or more of oxygen (O), sulfur (S), nitrogen (N), phosphorus (P) or silicon (Si), including any oxidized form of nitrogen (N), sulfur (S) or phosphorus (P), any quaternized form of basic nitrogen, and nitrogen atoms that can be substituted in heterocycles.

[0030] The term "aliphatic" refers to non-aromatic hydrocarbons or groups derived from them.

[0031] The term "aromatic" refers to a group containing an aromatic hydrocarbon ring, which optionally includes heteroatoms or substituents.

[0032] The term "substitution" is used to describe a compound or chemical moiety in which at least one hydrogen atom is replaced by a second chemical moiety. Examples of substituents include, but are not limited to, halogens; alkyl; heteroalkyl; alkenyl; ynyl; enynyl; aryl; heteroaryl; hydroxyl; alkoxy; amino; nitro; mercapto; alkylthio; imino; cyano; amide; phosphonato; hypophosphono; carboxyl; thiocarbonyl; sulfonyl; sulfonamide; acyl; formyl; acyloxy; alkoxycarbonyl; carbonyl; haloalkyl; carbocyclic cycloalkyl; carbocyclic or heterocyclic aryl; amino, monoalkylamino and dialkylamino; and ortho-lower alkyl. The substituents include: alkyl; o-aryl, aryl; aryl-lower alkyl; -CO2CH3; -CONH2; -OCH2CONH2; -NH2; -SO2NH2; -OCHF2; -CF3; -OCF3; -NH(alkyl); -N(alkyl)2; -NH(aryl); -N(alkyl)(aryl); -N(aryl)2; -CHO; -CO(alkyl); -CO(aryl); -CO2(alkyl); and -CO2(aryl); and these moieties may optionally be substituted with fused ring structures or bridged structures. These substituents may optionally be further substituted with one or more substituents. Unless otherwise specified, all chemical groups may be substituted.

[0033] The term "halogen" or "halogen" refers to F, Cl, Br, or I.

[0034] The term "polymer" refers to a polymer compound prepared by polymerizing monomers (whether of the same or different types). The general term "polymer" encompasses both "homogeneous polymers" and "copolymers".

[0035] The term "homogeneous polymer" refers to a polymer formed by the polymerization of a single monomer.

[0036] The term "copolymer" refers to a polymer formed by the polymerization of two or more monomers of different types.

[0037] The term "monomer unit" refers to the structural unit of a polymer derived from a single monomer.

[0038] The term "structural unit" refers to a total monomer unit derived from the same monomer type in a polymer.

[0039] The term "weight-average molecular weight" (M) for polymers w In mathematics, it is defined as: Where N i It has a specific molecular weight M i The number of polymer molecules.

[0040] The term "hydrophilicity" refers to the property of a substance to have an affinity for water, readily combining with it. This property is often associated with substances that are polar or ionic, capable of interacting with water molecules. Hydrophilic substances or materials have a tendency to interact with or mix with water, making them easily wetted or dissolved. In some embodiments, hydrophilic substances or materials contain functional groups that have a tendency to interact with water molecules to form hydrogen bonds. These functional groups are themselves polar and inherently hydrophilic, and can be referred to as "hydrophilic functional groups." Some non-limiting examples of hydrophilic functional groups include acid groups, hydroxyl groups, and amide groups.

[0041] The term "aqueous neutral" refers to the property of a substance or material that is insoluble or only partially soluble in polar solvents, especially water. Aqueous neutral functional groups are typically polar themselves and tend to interact with water molecules, but unlike hydrophilic functional groups, they cannot form hydrogen bonds with water molecules due to the lack of hydrogen atoms (although they can accept hydrogen bonds from water molecules). Some non-limiting examples of aqueous neutral functional groups include nitrile and nitro groups.

[0042] The term "homogenizer" refers to a device that can uniformly disperse a mixture of materials, keeping the composition of the mixture homogeneous. In some embodiments, the homogenization process is carried out under fluid conditions, uniformly dispersing the materials in the fluid, for example, dispersing electrode components in a solvent to prepare an electrode slurry. In some embodiments, homogenization is achieved by mixing dry materials. In another embodiment, homogenization can also be achieved by mixing different proportions of dry and liquid materials. Any conventional homogenizer can be used in the homogenization process of this invention. Some non-limiting examples of homogenizers include stirring mixers, planetary mixers, tumblers, and mills.

[0043] The term "apply" refers to the action of laying or spreading a substance on a surface.

[0044] 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.

[0045] For mixtures containing both volatile and nonvolatile substances, the term "solid content" refers to the amount of nonvolatile material remaining after the mixture has evaporated, while the term "solid fraction" for mixtures or compositions refers to this remaining nonvolatile material. Similarly, the term "liquid content" refers to the amount of material evaporated from the mixture, while the term "liquid fraction" for mixtures or compositions refers to this evaporated substance. The sum of the solid and liquid contents of a mixture equals the total mass of the mixture. Solid and liquid contents are typically expressed as a ratio or percentage relative to the total mass of the mixture. When the mixture contains no liquid, the solid content is 100%, and the liquid content is 0%.

[0046] The term "peel strength" refers to the magnitude of the force required to separate two mutually adhered materials (e.g., current collector and electrode layer); this indicator is used as a measure of the adhesion strength between the two materials and is usually expressed in N / cm.

[0047] The term "adhesive strength" refers to the force required to separate a substrate from the adhesive material adhered thereto; this indicator is used to measure the adhesive strength between the two materials and is usually expressed in N / cm.

[0048] The term "C-rate" refers to the charging or discharging rate of a battery whose total storage capacity is expressed in ampere-hours (Ah) or milliampere-hours (mAh). 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.

[0049] The term "ampere-hour (Ah)" is a unit used to describe the storage capacity of a battery. For example, a 1 Ah battery can provide 1 ampere of current for one hour or 0.5 amperes of current for two hours, and so on. Therefore, 1 ampere-hour (Ah) is equivalent to 3,600 coulombs of charge. Similarly, the term "milliampere-hour (mAh)" is also a unit of battery storage capacity and is 1,000th the capacity of an ampere-hour.

[0050] The term "capacity" is a characteristic of electrochemical cells, referring to the total amount of electric charge that an electrochemical cell (e.g., a battery) can hold. Capacity is usually expressed in ampere-hours (Ahs). 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.

[0051] In the following description, all numerical values ​​disclosed in this invention are approximate, regardless of whether they are combined with the terms "about" or "approximate." They can vary by 1%, 2%, 5%, or sometimes 10% to 20%. Whenever a lower limit R is disclosed...L and upper limit R U When the value is within a certain range, 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.

[0052] In this specification, all descriptions of the singular also include the plural, and vice versa. In this specification, without departing from the context, "aqueous solvent" may specifically refer to water.

[0053] Currently, electrodes are typically fabricated by preparing an electrode slurry by dispersing electrode active materials, binder materials, and conductive agents in a solvent, then coating the slurry onto a current collector and drying it. A widely used electrode slurry formulation includes PVDF as a binder and NMP as a solvent; however, the use of NMP poses significant environmental, health, and safety risks, necessitating the installation of a vapor recovery system, which incurs additional costs. When applied to dry electrode material mixtures, these traditional fluorinated binders, such as polyvinylidene fluoride (PVDF) and polytetrafluoroethylene (PTFE), can be fibrous, connecting electrode components during electrode layer fabrication. However, using fluorinated binders means that organic solvents must be used during recycling. The industry has also experimented with using water-compatible polymers as binders, but currently these binder polymers must be used with slurries containing relatively high levels of aqueous solvents, which can react with the positive electrode active material, causing its degradation and thus reducing battery performance.

[0054] This invention discloses a method for manufacturing an electrode material mixture for secondary batteries. The electrode material mixture comprises an electrode active material, a binder, and water; and may further comprise a conductive agent. The binder is a copolymer, wherein the copolymer comprises hydrophilic and non-hydrophilic structural units, and its weight-average molecular weight ranges within a specific range. Studies have found that when the electrode material mixture is prepared using the method of this invention, the copolymer readily undergoes fibrosis in the presence of a specific amount of water, and due to its inherent fibrosis tendency, it possesses excellent bonding properties, thereby enabling the fabrication of electrode layers with greater thickness.

[0055] In some embodiments, the electrode material mixture is formed by first homogenizing the electrode active material and the binder material to form a premix, wherein the binder material is a copolymer and is in a dry state. There are no particular limitations on the method of producing the copolymer, but in some embodiments, the water-compatible copolymer is produced by polymerization of a monomer, polymer, or monomer-polymer complex dispersed in an aqueous solvent, the polymerization being initiated by free radicals generated by a water-soluble free radical initiator. Any suitable reaction conditions can be used during the polymerization process, as long as the copolymer can be successfully formed.

[0056] Surprisingly, research has found that for the copolymer to possess ideal fibrous properties and excellent adhesive properties (such as bond strength), the molecular chain must simultaneously contain both hydrophilic and non-hydrophilic structural units. This adhesive force is attributed to the combined effect of hydrophilic and non-hydrophilic interactions between each structural unit and water molecules. Therefore, the copolymer in the adhesive composition of the present invention preferably contains both hydrophilic and non-hydrophilic structural units. Some non-limiting examples of monomers that can constitute hydrophilic structural units include monomers containing acidic groups, monomers containing amide groups, and combinations thereof; wherein the acidic group is selected from the group consisting of carboxylic acids, sulfonic acids, sulfuric acids, phosphonic acids, phosphoric acids, nitric acids, their salts, their derivatives, and combinations thereof. Some non-limiting examples of monomers that can constitute non-hydrophilic structural units include monomers containing nitrile groups.

[0057] The proportions of the structural units in a copolymer play a crucial role. When the proportion of hydrophilic structural units in the copolymer is too high, the copolymer becomes excessively hydrophilic, leading to a decline in battery performance. In this case, the copolymer's excessive affinity for water hinders the normal fibrosis process, resulting in poor performance when using this electrode material mixture to manufacture electrodes. During electrode fabrication, the presence of non-hydrophilic structural units in the copolymer prevents excessive hydrogen bonding with water, playing a vital role in maintaining the desired fibrosis behavior. On the other hand, when the proportion of non-hydrophilic structural units in the copolymer is too high, the copolymer loses its water compatibility, resulting in insufficient fibrosis and rendering it unsuitable as a binder. Therefore, finding a suitable balance among these structural units is crucial for ensuring water compatibility and optimal battery performance.

[0058] In some embodiments, the proportion of hydrophilic structural units, based on the total molar number of monomer units in the copolymer, is approximately 60% to 90%, approximately 63% to 90%, approximately 66% to 90%, approximately 69% to 90%, approximately 72% to 90%, approximately 75% to 90%, approximately 78% to 90%, approximately 81% to 90%, approximately 84% to 90%, approximately 87% to 90%; approximately 60% to 87%, approximately 63% to 87%, approximately 66% to 87%, approximately 69% to 87%, approximately 72% to 87%, approximately 75% to 87%, approximately 78% to 87%, approximately 81% to 87%, approximately 84% to 87%; approximately 60% to 84%, approximately 63% to 84%, approximately 66% to 84%, approximately 69% to 84 ...4%, approximately 72% to 84%, approximately 63% to 84%, approximately 66% to 84%, approximately 69% to 84%, approximately 72% to 84%, approximately 72% to 84%, approximately 63% to 84%, approximately 66% to 84%, approximately 69% to 84%, approximately 72% to 84%, approximately 72% to 84%, approximately 63% to 84%, approximately 66% to 84%, approximately 69% to 84%, approximately 72% to 84%, Approximately 84%, approximately 75% to approximately 84%, approximately 78% to approximately 84%, approximately 81% to approximately 84%; approximately 60% to approximately 81%, approximately 63% to approximately 81%, approximately 66% to approximately 81%, approximately 69% to approximately 81%, approximately 72% to approximately 81%, approximately 75% to approximately 81%, approximately 78% to approximately 81%; approximately 60% to approximately 78%, approximately 63% to approximately 78%, approximately 66% to approximately 78%, approximately 69% to approximately 78%, approximately 72% to approximately 78%, approximately 75% to approximately 78%; approximately 60% to approximately 75%, approximately 63% to approximately 75%, approximately 66% to approximately 75%, approximately 69% to approximately 75%, approximately 72% to approximately 75%; approximately 60% to approximately 69%, approximately 63% to approximately 69%, approximately 66% to approximately 69%; approximately 60% to approximately 66%, approximately 63% to approximately 66%; or approximately 60% to approximately 63%.

[0059] In some embodiments, the proportion of hydrophilic structural units in the copolymer is about 60%, about 63%, about 66%, about 69%, about 72%, about 75%, about 78%, about 81%, about 84%, about 87%, or about 90% by molar, based on the total molar number of monomer units in the copolymer. In some embodiments, the proportion of hydrophilic structural units is less than 90%, less than 87%, less than 84%, less than 81%, less than 78%, less than 75%, less than 72%, less than 69%, less than 66%, or less than 63% by molar. In some embodiments, the proportion of hydrophilic structural units is greater than 60%, greater than 63%, greater than 66%, greater than 69%, greater than 72%, greater than 75%, greater than 78%, greater than 81%, greater than 84%, or greater than 87% by molar.

[0060] In a preferred embodiment, the hydrophilic structural unit of the copolymer comprises monomeric units derived from monomers containing hydrophilic functional groups. In some embodiments, the monomer containing the hydrophilic functional group may be an acid-containing monomer or an amide-containing monomer. The acid group (e.g., a carboxylic acid group) is polar due to the electronegativity difference between the carbon and oxygen atoms in the carbonyl group and between the oxygen and hydrogen atoms in the hydroxyl group. The uneven charge distribution within the acid group results in a net dipole moment, thus giving the acid group high polarity. This high polarity makes the acid group highly hydrophilic and enables it to participate in hydrogen bond formation (through the hydroxyl group) and dipole-dipole interactions, making it a key functional group in the copolymer.

[0061] Similarly, amide groups are polar due to the different electronegativity of carbon and oxygen atoms in the carbonyl group and the different electronegativity of nitrogen and hydrogen atoms in the amine group. This uneven charge distribution results in a net dipole moment, giving the amide group a strong polarity. This high polarity makes the amide group highly hydrophilic. Similar to acid groups, amide groups can participate in hydrogen bonding (through the amine group) and dipole-dipole interactions. Therefore, it is another important functional group in copolymers.

[0062] 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, salts of these acids, derivatives of these acids, and combinations thereof. In some embodiments, the salt of the acid comprises an alkali metal cation. Examples of alkali metals include lithium, sodium, and potassium. In some embodiments, the salt of the acid comprises an ammonium cation. In some embodiments, the acid group specifically comprises one or more of the above-mentioned acids and one or more of their salts.

[0063] 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. In some embodiments, the carboxylic acid is 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, fluoroalkyl hydrogen maleate, or a combination thereof. In some embodiments, the carboxylic acid is maleic anhydride, methylmaleic anhydride, dimethylmaleic anhydride, acrylic anhydride, methacrylic anhydride, or a combination thereof.

[0064] 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.

[0065] In some embodiments, the sulfuric acid is allyl hydrogen sulfate, ethylene hydrogen sulfate, 4-allylphenol sulfate, or a combination thereof.

[0066] 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.

[0067] 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, (meth)acryloyloxyethyl phosphate, (meth)acryloyloxypropyl The following are compounds: methyl 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 tripylate, vinyl tripylate, isopentenyl phosphate, isopentenyl pyrophosphate, or combinations thereof, wherein (meth)acryloyl group refers to acryloyl group or methacryloyl group.

[0068] In some embodiments, the nitric acid is allyl hydrogen nitrate, vinyl hydrogen nitrate, or a combination thereof.

[0069] In some embodiments, the proportion of monomer units derived from acid-containing monomers in the copolymer is approximately 10% to approximately 40%. When the proportion of monomer units derived from acid-containing monomers in the copolymer exceeds this range, the copolymer will lack the necessary structural organization and intermolecular interactions required for proper fiberization, which will lead to a significant reduction in the adhesive strength of the copolymer and reduce its overall effectiveness as a binder material. Conversely, when the proportion of monomer units derived from acid-containing monomers in the copolymer is below the above range, the copolymer's water compatibility is also insufficient for proper fiberization. Therefore, it is crucial to strictly control and maintain the proportion of monomer units derived from acid-containing monomers in the copolymer within the specified range.

[0070] In some embodiments, based on the total molar number of monomer units in the copolymer, the proportion of monomer units derived from acid-containing monomers in the copolymer is, on a molar basis, about 10% to about 40%, about 12% to about 40%, about 15% to about 40%, about 18% to about 40%, about 20% to about 40%, about 22% to about 40%, about 25% to about 40%, about 28% to about 40%, about 30% to about 40%, about 32% to about 40%, about 35% to about 40%, about 10% to about 35%, about 12% to about 35%, about 15% to about 35%, about 18% to about 35%, and about 20% to about 35%. Approximately 22% to approximately 35%, approximately 25% to approximately 35%, approximately 28% to approximately 35%, approximately 30% to approximately 35%, approximately 10% to approximately 30%, approximately 12% to approximately 30%, approximately 15% to approximately 30%, approximately 18% to approximately 30%, approximately 20% to approximately 30%, approximately 22% to approximately 30%, approximately 25% to approximately 30%, approximately 10% to approximately 25%, approximately 12% to approximately 25%, approximately 15% to approximately 25%, approximately 18% to approximately 25%, approximately 20% to approximately 25%, approximately 10% to approximately 20%, approximately 12% to approximately 20%, approximately 15% to approximately 20%, approximately 10% to approximately 15%, or approximately 12% to approximately 15%.

[0071] In some embodiments, based on the total molar number of monomer units in the copolymer, the proportion of monomer units derived from acid-containing monomers in the copolymer is about 10%, about 12%, about 15%, about 18%, about 20%, about 22%, about 25%, about 28%, about 30%, about 32%, about 35%, about 38%, or about 40% by molar. In some embodiments, based on the total molar number of monomer units in the copolymer, the proportion of monomer units derived from acid-containing monomers in the copolymer is 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%, less than 18%, less than 15%, or less than 12% by molar. In some embodiments, based on the total molar number of monomer units in the copolymer, the proportion of monomer units derived from acid-containing monomers in the copolymer is greater than 10%, greater than 12%, greater than 15%, greater than 18%, greater than 20%, greater than 22%, greater than 25%, greater than 28%, greater than 30%, greater than 32%, greater than 35%, or greater than 38% by molar.

[0072] 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, N-(propoxymethyl)methacrylamide, N-(butoxymethyl)methacrylamide, N,N-dimethylaminopropylmethacrylamide, N,N-dimethylaminoethylmethacrylamide, N,N-dihydroxymethylmethacrylamide, diacetone methacrylamide, diacetone acrylamide, methacryloylmorpholine, N-hydroxymethylacrylamide, N-methoxymethylacrylamide, N,N'-methylenebisacrylamide (MBA), N-hydroxymethylacrylamide, or combinations thereof.

[0073] In some embodiments, the proportion of monomer units derived from amide-containing monomers in the copolymer is from about 10% to about 55%. When the proportion of monomer units derived from amide-containing monomers in the copolymer exceeds the above range, the copolymer will lack the structural organization and intermolecular interactions required for proper fiberization, which will lead to a significant reduction in the adhesive strength of the copolymer and reduce its overall effectiveness as a binder material. Conversely, when the proportion of monomer units derived from amide-containing monomers in the copolymer is below the above range, the copolymer's water compatibility is also insufficient for proper fiberization. Therefore, it is crucial to strictly control and maintain the proportion of monomer units derived from amide-containing monomers in the copolymer within the specified range.

[0074] In some embodiments, based on the total molar number of monomer units in the copolymer, the proportion of monomer units derived from amide-containing monomers in the copolymer is, on a molar basis, about 10% to about 55%, about 15% to about 55%, about 20% to about 55%, about 25% to about 55%, about 30% to about 55%, about 35% to about 55%, about 40% to about 55%, about 45% to about 55%, about 50% to about 55%, about 10% to about 50%, about 15% to about 50%, about 20% to about 50%, about 25% to about 50%, about 30% to about 50%, about 35% to about 50%, about 40% to about 50%, about 45% to about 50%, about 10% to about 45%, about 15% to about 45%, and about 20% to about 45%. Approximately 25% to approximately 45%, approximately 30% to approximately 45%, approximately 35% to approximately 45%, approximately 40% to approximately 45%, approximately 10% to approximately 40%, approximately 15% to approximately 40%, approximately 20% to approximately 40%, approximately 25% to approximately 40%, approximately 30% to approximately 40%, approximately 35% to approximately 40%, approximately 10% to approximately 35%, approximately 15% to approximately 35%, approximately 20% to approximately 35%, approximately 25% to approximately 35%, approximately 30% to approximately 35%, approximately 10% to approximately 30%, approximately 15% to approximately 30%, approximately 20% to approximately 30%, approximately 25% to approximately 30%, approximately 10% to approximately 25%, approximately 15% to approximately 25%, approximately 20% to approximately 25%, approximately 10% to approximately 20%, approximately 15% to approximately 20%, or approximately 10% to approximately 15%.

[0075] In some embodiments, based on the total molar number of monomer units in the copolymer, the proportion of monomer units derived from amide-containing monomers in the copolymer is about 10%, about 15%, about 20%, about 25%, about 30%, about 35%, about 40%, about 45%, about 50%, or about 55% by molar. In some embodiments, based on the total molar number of monomer units in the copolymer, the proportion of monomer units derived from amide-containing monomers in the copolymer is less than 55%, less than 50%, less than 45%, less than 40%, less than 35%, less than 30%, less than 25%, less than 20%, or less than 15% by molar. In some embodiments, based on the total molar number of monomer units in the copolymer, the proportion of monomer units derived from amide-containing monomers in the copolymer is greater than 10%, greater than 15%, greater than 20%, greater than 25%, greater than 30%, greater than 35%, greater than 40%, greater than 45%, or greater than 50% by molar.

[0076] The hydroxyl group is a hydrophilic functional group. However, studies have found that the fibrous properties of copolymers decrease when they contain monomer units derived from hydroxyl-containing monomers. Therefore, in a preferred embodiment, the copolymer components intentionally do not contain any monomer units derived from hydroxyl-containing monomers.

[0077] In some embodiments, the non-hydrophilic structural units of the copolymer comprise monomer units derived from nitrile-containing monomers. The nitrile group is considered aquatic neutral functional groups; it is not hydrophilic itself but retains sufficient polarity to avoid excessively reducing the overall water compatibility of the copolymer. The nitrile group exhibits polarity because the shared electrons in the covalent CN bond are more inclined towards the N atom than the C atom. This allows the nitrile group to form strong intermolecular forces with acid and amide groups contained in another copolymer chain. Furthermore, the nitrogen atom (N) in the nitrile group (-C≡N) can form hydrogen bonds that accept water molecules. However, the nitrile group does not contain a hydrogen atom, so it cannot form hydrogen bonds itself. Therefore, the nitrile group is not considered hydrophilic but rather aquatic.

[0078] 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.

[0079] In some embodiments, the proportion of monomer units derived from nitrile-containing monomers in the copolymer is from about 10% to about 40%. The presence of these nitrile-derived monomer units helps to increase the overall polarity of the copolymer while avoiding excessive water compatibility, thus allowing the copolymer to interact appropriately with water without hindering the fibrosis process. This ensures that the copolymer retains its function as a binder when preparing electrodes using electrode material mixtures.

[0080] In some embodiments, based on the total molar number of monomer units in the copolymer, the proportion of monomer units derived from nitrile-containing monomers in the copolymer is, on a molar basis, about 10% to about 40%, about 12% to about 40%, about 15% to about 40%, about 18% to about 40%, about 20% to about 40%, about 22% to about 40%, about 25% to about 40%, about 28% to about 40%, about 30% to about 40%, about 32% to about 40%, about 35% to about 40%, about 10% to about 35%, about 12% to about 35%, about 15% to about 35%, about 18% to about 35%, and about 20% to about 35%. Approximately 22% to approximately 35%, approximately 25% to approximately 35%, approximately 28% to approximately 35%, approximately 30% to approximately 35%, approximately 10% to approximately 30%, approximately 12% to approximately 30%, approximately 15% to approximately 30%, approximately 18% to approximately 30%, approximately 20% to approximately 30%, approximately 22% to approximately 30%, approximately 25% to approximately 30%, approximately 10% to approximately 25%, approximately 12% to approximately 25%, approximately 15% to approximately 25%, approximately 18% to approximately 25%, approximately 20% to approximately 25%, approximately 10% to approximately 20%, approximately 12% to approximately 20%, approximately 15% to approximately 20%, approximately 10% to approximately 15%, or approximately 12% to approximately 15%.

[0081] In some embodiments, based on the total molar number of monomer units in the copolymer, the proportion of monomer units derived from nitrile-containing monomers in the copolymer is about 10%, about 12%, about 15%, about 18%, about 20%, about 22%, about 25%, about 28%, about 30%, about 32%, about 35%, about 38%, or about 40% by molar. In some embodiments, based on the total molar number of monomer units in the copolymer, the proportion of monomer units derived from nitrile-containing monomers in the copolymer is 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%, less than 18%, less than 15%, or less than 12% by molar. In some embodiments, based on the total molar number of monomer units in the copolymer, the proportion of monomer units derived from nitrile-containing monomers in the copolymer is greater than 10%, greater than 12%, greater than 15%, greater than 18%, greater than 20%, greater than 22%, greater than 25%, greater than 28%, greater than 30%, greater than 32%, greater than 35%, or greater than 38% by molar.

[0082] Subsequent studies have shown that the fibrosis of copolymers is adversely affected when they consist of monomer units derived from certain specific types of monomers, even if these monomer units could otherwise be considered part of a non-hydrophilic structural unit. These specific types of monomers include ester-containing monomers, epoxy-containing monomers, ether-containing monomers, carbonyl-containing monomers, and fluorinated monomers. In such cases, the presence of these monomers in the copolymer hinders the desired fibrosis process. Therefore, in a preferred embodiment, excluding any monomer units derived from the aforementioned monomers is advantageous for the copolymer. By avoiding the introduction of these specific monomers, the copolymer can circumvent the concurrency problems associated with their adverse effects on fibrosis. This ensures that the copolymer maintains its intended fibrosis behavior; maintaining the intended fibrosis behavior improves the performance and suitability of the copolymer when manufacturing electrodes using the dry electrode material mixtures of the present invention. In some embodiments, the non-hydrophilic structural unit does not contain ester-containing monomers, epoxy-containing monomers, ether-containing monomers, carbonyl-containing monomers, fluorinated monomers, or combinations thereof.

[0083] In other embodiments, the non-hydrophilic structural unit of the copolymer comprises a monomer unit derived from an olefin. Any hydrocarbon having at least one carbon-carbon double bond can be used as the olefin. In some embodiments, the olefin comprises C2-C... 20 Aliphatic compounds, C8-C containing vinyl unsaturated bonds 20 Aromatic or cyclic compounds, C4-C 40 Dienes and combinations thereof. In some embodiments, the olefin is styrene, ethylene, propylene, isobutene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicosene, 3-methyl-1-butene, cyclobutene, 3-methyl-1-pentene, 4-methyl-1-pentene, 4,6-dimethyl-1-heptene, 4-vinylcyclohexene, vinylcyclohexane, norbornene, norbornadiene, ethylidene norbornene, cyclopentene, cyclohexene, dicyclopentadiene, cyclooctene, or combinations thereof. In some embodiments, the aqueous copolymer does not contain structural units derived from olefins. Conjugated dienes constitute olefins. In some embodiments, the conjugated dienes are selected from C4-C64. 40Dienes; aliphatic conjugated dienes, such as 1,3-butadiene, 1,3-pentadiene, 1,4-hexadiene, 1,5-hexadiene, 1,7-octadiene, 1,9-decadiene, isoprene, geraniol, 2-methyl-1,3-butadiene, 2,3-dimethyl-1,3-butadiene, 2-chloro-1,3-butadiene, substituted linear conjugated pentadienes, substituted branched conjugated hexadienes, and combinations thereof. Studies have found that the presence of olefin-derived monomer units has no significant effect on the fiberization process, but the proportion of olefin-derived monomer units in the copolymer must be strictly controlled to maintain the desired fiberization properties, preferably not exceeding approximately 15% of the total molar number of monomer units in the copolymer. Under this constraint, the copolymer can be effectively fiberized without any significant negative impact. This ensures that the copolymer retains its desired structural and functional properties, making it suitable for a variety of applications where fiberization is crucial.

[0084] This invention also investigated the effect of introducing monomer units derived from aromatic vinyl monomers into copolymers on copolymer fibrosis. These monomer units can be considered as part of a non-hydrophilic structural unit. In some embodiments, the aromatic vinyl monomer is styrene, α-methylstyrene, vinyltoluene, divinylbenzene, or a combination thereof. However, studies have found that the fibrosis properties of copolymers decrease when they contain monomer units derived from aromatic vinyl monomers. This negative impact can be attributed to steric hindrance caused by the large aromatic groups. Steric hindrance interferes with the interaction between the two copolymer chains and restricts the slippage between copolymer chains during fibrosis. Therefore, it is recommended to avoid using monomer units derived from any such aromatic vinyl monomers.

[0085] The weight-average molecular weight of the copolymer is within the range described below. Surprisingly, studies have found that this molecular weight range is crucial for ensuring good fibrous properties. When the weight-average molecular weight of the copolymer is within the disclosed range, the electrode material mixture can form an electrode layer with strong adhesion and peel strength. This allows the electrode layer to be made thicker, thereby increasing the energy density of the battery without sacrificing cycle characteristics and maintaining performance stability during repeated charge-discharge cycles. Therefore, the copolymer of the present invention not only serves as an effective binder but also contributes to improving the overall performance and durability of the battery.

[0086] In some embodiments, the copolymer has a weight-average molecular weight of about 400,000 g / mol to about 700,000 g / mol, about 450,000 g / mol to about 700,000 g / mol, about 500,000 g / mol to about 700,000 g / mol, about 550,000 g / mol to about 700,000 g / mol, about 600,000 g / mol to about 700,000 g / mol, about 650,000 g / mol to about 700,000 g / mol, about 400,000 g / mol to about 650,000 g / mol, about 450,000 g / mol to about 650,000 g / mol, about 500,000 g / mol to about 650,000 g / mol, and about 550,000 g / mol to about 650,000 g / mol. g / mol, about 600,000 g / mol to about 650,000 g / mol, about 400,000 g / mol to about 600,000 g / mol, about 450,000 g / mol to about 600,000 g / mol, about 500,000 g / mol to about 600,000 g / mol, about 550,000 g / mol to about 600,000 g / mol, about 400,000 g / mol to about 550,000 g / mol, about 450,000 g / mol to about 550,000 g / mol, about 500,000 g / mol to about 550,000 g / mol, about 400,000 g / mol to about 500,000 g / mol, or about 400,000 g / mol to about 500,000 g / mol. g / mol to approximately 450,000 g / mol.

[0087] In some embodiments, the copolymer has a weight-average molecular weight of less than 700,000 g / mol, less than 650,000 g / mol, less than 600,000 g / mol, less than 550,000 g / mol, less than 500,000 g / mol, or less than 450,000 g / mol. In some embodiments, the copolymer has a weight-average molecular weight of greater than 400,000 g / mol, greater than 450,000 g / mol, greater than 500,000 g / mol, greater than 550,000 g / mol, greater than 600,000 g / mol, or greater than 650,000 g / mol.

[0088] In some embodiments, the current collector is an aluminum foil substrate, therefore the adhesive strength between the copolymer and the aluminum foil substrate can be a good indicator of the copolymer's adhesion to the current collector. In some embodiments, the adhesive strength between the copolymer and the aluminum foil substrate is about 1 N / cm to about 10 N / cm, about 2 N / cm to about 10 N / cm, about 3 N / cm to about 10 N / cm, about 4 N / cm to about 10 N / cm, or about 5 N / cm to about 10 N / cm. In some embodiments, the adhesive strength between the copolymer and the aluminum foil substrate is less than 10 N / cm, less than 9 N / cm, less than 8 N / cm, less than 7 N / cm, less than 6 N / cm, less than 5 N / cm, less than 4 N / cm, less than 3 N / cm, or less than 2 N / cm. In some embodiments, the adhesive strength between the copolymer and the aluminum foil substrate is greater than 1 N / cm, 2 N / cm, 3 N / cm, 4 N / cm, 5 N / cm, 6 N / cm, 7 N / cm, 8 N / cm, or 9 N / cm.

[0089] As described above, in the manufacturing method of the present invention, the production of the premix involves adding a copolymer in a dried state. For many adhesive polymers, once they are completely dried, an irreversible change occurs, preventing them from redissolving in aqueous solvents. This adversely affects the adhesive properties, and therefore complete drying is not recommended. However, the copolymers disclosed in this invention retain their functionality even after complete drying and rehydration. This means that the post-polymer mixture produced by the copolymerization reaction can be dried to essentially no liquid residue, and the dried adhesive material can be used directly in the premixing process without always keeping the copolymer in water. This reduces the volume required for storage.

[0090] There are no particular limitations on the dryer and drying conditions used, but the dryer should be able to remove the liquid content from the reaction mixture under the relevant conditions without damaging the copolymers in the mixture. In some embodiments, the dryer may be a spray dryer, freeze dryer, disc dryer, rotary dryer, screw dryer, fluidized bed dryer, drum dryer, vacuum dryer, or a combination thereof.

[0091] Since copolymer chains must slide against each other to undergo fibrosis, it is preferable that the copolymer does not form a single macromolecule through crosslinking, as this would hinder the sliding between different copolymer chains. Therefore, in a preferred embodiment, the copolymer does not contain any monomer units derived from the crosslinking monomer. In some embodiments, based on the total molar number of monomer units in the copolymer, the proportion of monomer units derived from the crosslinking monomer in the copolymer is less than 0.25%, less than 0.2%, less than 0.15%, less than 0.1%, less than 0.05%, less than 0.02%, or less than 0.01% on a molar basis. In some embodiments, the crosslinking monomer includes ethylene glycol diacrylate, ethylene glycol dimethacrylate, tri(propylene glycol) dimethacrylate, tetra(ethylene glycol) diacrylate, N,N'-methylenebis(acrylamide), poly(ethylene glycol) diacrylate, poly(ethylene glycol) dimethacrylate, poly(propylene glycol) diacrylate, poly(propylene glycol) dimethacrylate, trimethylolpropane ethoxylated triacrylate, trimethylolpropane propoxylated triacrylate, divinylbenzene, polyester dimethyl acrylate, etc. Acrylates, divinyl ethers, trimethylolpropane trimethacrylate, bisphenol A ethoxylated dimethacrylate, 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, di(trimethylolpropane)tetraacrylate, pentaerythritol tetraacrylate, pentaerythritol ethoxylated tetraacrylate, di(pentaerythritol)pentaacrylate, di(pentaerythritol)hexaacrylate, glycerol triacrylate, glycerol trimethacrylate, glycerol propoxylated triacrylate, their derivatives, isomers, or combinations thereof.

[0092] Electrode active materials can be either positive or negative electrode active materials, forming positive or negative electrode mixtures, respectively. Positive electrode active materials are generally unstable in the presence of water, leading to unwanted reactions and the formation of impurities such as lithium hydroxide (LiOH). These impurities negatively impact the electrochemical performance of the battery, a significant drawback of water-based electrode slurries. To address this issue, various methods have been developed to make positive electrode active materials waterproof. For example, one method is to coat the positive electrode active material, forming a core-shell structure. However, these methods increase production costs, extend manufacturing time, and ironically, they may still compromise battery performance.

[0093] The electrode material mixture disclosed in this invention has a low water content. Therefore, when the method of this invention is specifically used to manufacture the positive electrode mixture, degradation of the positive electrode active material due to reaction with water can be effectively prevented. This method also has advantages such as eliminating the need for protective measures for the positive electrode active material, thereby reducing material costs and shortening production time.

[0094] In some embodiments, the electrode active material is selected from LiCoO2, LiNiO2, LiNix Mn y O2, LiCo x Ni y O2, Li 1+z Ni x Mn y Co 1-x-y O2(NMC), LiNi x Co y Al z The cathode active material comprises the group consisting of O2(NCA), LiV2O5, LiTiS2, LiMoS2, LiMnO2, LiCrO2, LiMn2O4, Li2MnO3, LiFeO2, LiFePO4, and combinations thereof, wherein each x is independently 0.1 to 0.9; each y is independently 0 to 0.9; and each z is independently 0 to 0.4. In some embodiments, each x, y, and z in the above general formula has an independent interval of 0.01. 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, LiNi x Co y Al z O2 or LiCo x Ni y O2, wherein each x is independently 0.1 to 0.9; each y is independently 0 to 0.9; and each z is independently 0 to 0.4. 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 LiMPO4, wherein M is selected from the group consisting of Fe, Co, Ni, Mn, Al, Mg, Zn, Ti, La, Ce, Sn, Zr, Ru, Si, Ge, or combinations thereof. In some embodiments, the cathode active material is selected from LiFePO4, LiCoPO4, LiNiPO4, LiMnPO4, LiMnFePO4, and LiMn x Fe (1-x)a group consisting of PO4 and combinations thereof; wherein 0<x<1. In some embodiments, the cathode active material is LiNi x Mn y O4; wherein 0.1≤x≤0.9 and 0≤y≤2. In some embodiments, the cathode active material is xLi2MnO3·(1-x)LiMO2, wherein M is selected from the group consisting of Ni, Co, Mn and combinations thereof; and wherein 0<x<1. In some embodiments, the cathode active material is Li3V2(PO4)3 or LiVPO4F. In some embodiments, the cathode active material has a general formula Li2MSiO4, wherein M is selected from the group consisting of Fe, Co, Mn, Ni and combinations thereof.

[0095] In some embodiments, the cathode active material is doped with a dopant selected from the group consisting of Co, Cr, V, Mo, Nb, Pd, F, Na, Fe, Ni, Mn, Al, Mg, Zn, Ti, La, Ce, Sn, Zr, Ru, Si, Ge and combinations thereof. In some embodiments, the dopant is not Co, Cr, V, Mo, Nb, Pd, F, Na, Fe, Ni, Mn, Mg, Zn, Ti, La, Ce, Ru, Si or Ge. In some embodiments, the dopant is not Al, Sn or Zr.

[0096] In some embodiments, the cathode active material comprises or is itself a core-shell composite material having a core and a shell structure. In some embodiments, the core comprises one or more lithium transition metal oxides. In some embodiments, the shell comprises one or more lithium transition metal oxides and / or one or more transition metal oxides. In some embodiments, the one or more lithium transition metal oxides are selected from the group consisting of Li 1+x Ni a Mn b Co c Al (1-a-b-c) O2, LiCoO2, LiNiO2, LiMnO2, LiMn2O4, Li2MnO3, LiCrO2, Li4Ti5O 12 , LiV2O5, LiTiS2, LiMoS2, LiCo a Ni b O2, LiMn a Ni bThe group consisting of O2 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, each lithium transition metal oxide is independently doped with one or more dopants selected from the group consisting of Co, Cr, V, Mo, Nb, Pd, F, Na, Fe, Ni, Mn, Al, Mg, Zn, Ti, La, Ce, Sn, Zr, Ru, Si, Ge, and combinations thereof. In some embodiments, the one or more transition metal oxides are selected from the group consisting of Fe2O3, MnO2, Al2O3, MgO, ZnO, TiO2, La2O3, CeO2, SnO2, ZrO2, RuO2, and combinations thereof.

[0097] In some embodiments, the core and the shell each comprise one or more lithium transition metal oxides. In some embodiments, the lithium transition metal oxides in the core and the shell may be the same, different, or partially different. In some embodiments, when the core or the shell comprises two or more lithium transition metal oxides, the two or more lithium transition metal oxides are uniformly distributed on the core or the shell. In some embodiments, when the core or the shell comprises two or more lithium transition metal oxides, the two or more lithium transition metal oxides are not uniformly distributed on the core or the shell. In some embodiments, the cathode active material is not a core-shell composite material.

[0098] In some embodiments, the diameter of the core 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 1 µm to about 3 µm, about 1 µm to about 40 µm, about 10 µm to about 40 µm, about 20 µm to about 40 µm, about 30 µm to about 40 µm, about 1 µm to about 30 µm, about 5 µm to about 30 µm, about 10 µm to about 30 µm, about 20 µm to about 30 µm, about 1 µm to about 25 µm, about 5 µm to about 25 µm, about 10 µm to about 25 µm, about 15 µm to about 25 µm, about 1 µm to about 20 µm, about 5 µm to about 20 µm, about 10 µm to about 20 µm, or about 15 µm. The thickness of the shell is approximately 1 µm to approximately 20 µm. In some embodiments, the shell thickness is approximately 1 µm to approximately 20 µm, approximately 3 µm to approximately 20 µm, approximately 5 µm to approximately 20 µm, approximately 10 µm to approximately 20 µm, approximately 1 µm to approximately 15 µm, approximately 3 µm to approximately 15 µm, approximately 5 µm to approximately 15 µm, approximately 1 µm to approximately 10 µm, approximately 3 µm to approximately 10 µm, or approximately 5 µm to approximately 10 µm. In some embodiments, the diameters of the core and shell are each independently greater than or less than the values ​​of 1 µm, 2 µm, 3 µm, 4 µm, 5 µm, 6 µm, 7 µm, 8 µm, 9 µm, 10 µm, 11 µm, 12 µm, 13 µm, 14 µm, 15 µm, 16 µm, 17 µm, 18 µm, 19 µm, and 20 µm. In some embodiments, the diameter or thickness ratio of the core to the shell 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 embodiments, the volume or weight ratio of the core to the shell is 95:5, 90:10, 80:20, 70:30, 60:40, 50:50, 40:60, or 30:70.

[0099] In some embodiments, the electrode active material is selected from natural graphite particles, synthetic graphite particles, hard carbon, soft carbon, mesophase carbon microspheres (MCMB), Sn particles, SnO2, SnO, Li4Ti5O 12 Anode active materials consisting of particles, Si particles, Si-C composite particles, and combinations thereof.

[0100] In some embodiments, the anolyte is doped with a dopant. In some embodiments, the dopant is selected from the group consisting of Fe, Ni, Mn, Al, Mg, Zn, Ti, La, Ce, Sn, Zr, Ru, and combinations thereof. In some embodiments, the dopant is B, Si, Ge, N, P, F, S, Cl, I, Se, or combinations thereof. In other embodiments, the anolyte is not doped. In some embodiments, the anolyte is not doped with Fe, Ni, Mn, Al, Mg, Zn, Ti, La, Ce, Sn, Zr, Ru, B, Si, Ge, N, P, F, S, Cl, I, or Se.

[0101] In some embodiments, the anolyte material comprises or is itself a core-shell composite material with a core and shell structure. In some embodiments, the core is selected from natural graphite particles, synthetic graphite particles, hard carbon, soft carbon, mesophase carbon microspheres (MCMB), Sn particles, SnO2, SnO, Li4Ti5O. 12 The group consisting of particles, Si particles, Si-C composite particles, and combinations thereof. In some embodiments, the shell is selected from soft carbon, hard carbon, natural graphite particles, synthetic graphite particles, mesophase carbon microspheres (MCMB), Kish graphite, pyrolytic carbon, mesophase pitch, mesophase pitch-based carbon fibers, Sn particles, SnO2, SnO, Li4Ti5O 12 A group consisting of particles, Si particles, Si-C composite particles, and combinations thereof.

[0102] In some embodiments, the electrode mixture material may further comprise a conductive agent. The presence of a conductive agent in the electrode material mixture may be advantageous because it can enhance the conductivity of the electrode. In embodiments where such a conductive agent is part of the electrode material mixture, the conductive agent is homogenized to prepare a premix, in addition to the electrode active material and the drying binder material. Any suitable material can be used as the conductive agent. In some embodiments, the conductive agent is a carbonaceous material. Some non-limiting examples include carbon, carbon black, graphite, expanded graphite, graphene, graphene nanosheets, carbon fibers, carbon nanofibers, graphitized carbon sheets, carbon nanotubes, carbon nanotubes, activated carbon, Super P, KS6, vapor-grown carbon fibers (VGCF), mesoporous carbon, and combinations thereof. In some embodiments, the conductive agent does not comprise a carbonaceous material.

[0103] In some embodiments, the conductive agent is a conductive polymer selected from the group consisting of polypyrrole, polyaniline, polyacetylene, polyphenylene sulfide (PPS), polyphenylacetylene (PPV), poly(3,4-ethylenedioxythiophene) (PEDOT), polythiophene, and combinations thereof. In some embodiments, the conductive agent also acts as a binder composition. In some embodiments, the conductive agent is a mixture of a carbonaceous material and a conductive polymer. In other embodiments, the conductive agent does not contain a conductive polymer.

[0104] The electrode mixture material may also contain additives as needed to obtain desired electrode properties. Such additives are added to the electrode active material and the drying binder material (and a conductive agent, if present), and homogenized to prepare a premix. In some embodiments, the additive is a conductive polymer used in addition to a conductive agent.

[0105] There are no particular limitations on the methods used to homogenize the materials to prepare the premix, as long as all electrode components are thoroughly mixed. For example, this can be achieved by using a homogenizer. The use of a homogenizer helps to thoroughly mix the electrode components, thereby ensuring that they are uniformly mixed and consistently dispersed. This homogenization step is crucial for obtaining a stable and optimally distributed mixture of electrode materials. Furthermore, the uniform distribution of electrode components in the coated electrode layer plays an important role in manufacturing batteries with good electrochemical performance.

[0106] This invention can use any homogenizer capable of promoting a uniform distribution of electrode components to prepare a premix. In some embodiments, the homogenizer is a screw mixer, mill, stirred mixer, or planetary mixer. Since the homogenization of these components is carried out in a dry state, grounding helps prevent any adverse effects from static electricity, which could disrupt the uniform distribution and stability of the electrode components in the premix. Therefore, in some embodiments, the homogenizer is grounded to reduce the effect of static electricity on the premix.

[0107] There is no particular limitation on the mixing time when preparing the premix, but it is essential to ensure that the electrode components are evenly distributed. Therefore, it is crucial to ensure that the mixing time is sufficiently long to achieve this. In some embodiments, the homogenization time after adding all electrode components to prepare the premix is ​​from about 1 minute to about 60 minutes. In some embodiments, the homogenization time after adding all electrode components to prepare the premix is ​​less than 60 minutes, less than 50 minutes, less than 40 minutes, less than 30 minutes, less than 20 minutes, less than 15 minutes, less than 10 minutes, less than 9 minutes, less than 8 minutes, less than 7 minutes, less than 6 minutes, less than 5 minutes, less than 4 minutes, less than 3 minutes, or less than 2 minutes. In some embodiments, the homogenization time after adding all electrode components to prepare the premix is ​​more than 1 minute, more than 2 minutes, more than 3 minutes, more than 4 minutes, more than 5 minutes, more than 6 minutes, more than 7 minutes, more than 8 minutes, more than 9 minutes, more than 10 minutes, more than 15 minutes, more than 20 minutes, more than 30 minutes, more than 40 minutes, or more than 50 minutes.

[0108] Maintaining an appropriate temperature during the homogenization of electrode components to prepare a premix helps promote efficient mixing and enhances the uniformity and binding of the electrode components in the premix. Therefore, the homogenizer can be equipped with a temperature control system to homogenize the electrode components at elevated temperatures to prepare the premix. In some embodiments, the electrode components are premixed at temperatures from about 5°C to about 50°C. In some embodiments, the electrode components are premixed at temperatures below 50°C, below 45°C, below 40°C, below 35°C, below 30°C, below 25°C, below 20°C, below 15°C, or below 10°C. In some embodiments, the electrode components are premixed at temperatures above 5°C, above 10°C, above 15°C, above 20°C, above 25°C, above 30°C, above 35°C, above 40°C, or above 45°C.

[0109] During homogenization, the rotational speed of the rotating elements in the homogenizer used to homogenize the electrode components to prepare a premix can be customized within a specified range, wherein the homogenizer can be a screw mixer, a stirred mixer, or a planetary mixer. By adjusting the rotational speed of the rotating elements, the intensity of the mixing action of the electrode components to prepare the premix can be changed. Higher speeds help to promote more vigorous mixing, while lower speeds provide a gentler mixing mode. This flexibility allows for precise control and optimization of the mixing conditions of the electrode components during premix preparation, depending on the specific requirements of the premix. In some embodiments, the rotational speed of each rotating element in the homogenizer used to homogenize the electrode components to prepare the premix is ​​independently from about 10 rpm to about 3000 rpm, about 10 rpm to about 100 rpm, about 100 rpm to about 3000 rpm, about 100 rpm to about 1000 rpm, about 500 rpm to about 3000 rpm, or about 500 rpm to about 2000 rpm. In some embodiments, the rotational speed of each rotating element in the homogenizer used to homogenize the electrode components to prepare a premix is ​​independently less than 3000 rpm, less than 2500 rpm, less than 2000 rpm, less than 1500 rpm, less than 1000 rpm, less than 500 rpm, less than 100 rpm, or less than 50 rpm. In some embodiments, the rotational speed of each rotating element in the homogenizer used to homogenize the electrode components to prepare a premix is ​​independently greater than 100 rpm, greater than 500 rpm, greater than 1000 rpm, greater than 1500 rpm, or greater than 2000 rpm.

[0110] The presence of water is crucial for the fiberization of the copolymer. Under anhydrous conditions, the copolymer exists as linear chains that interact strongly through various intermolecular forces, such as dipole-dipole, ion-dipole, dipole-induced dipole, and induced dipole-induced dipole interactions, as well as hydrogen bonds. A significant portion of these interactions are caused by functional groups located on each copolymer chain, such as the oriented pairing of nitrile groups (C≡N) in one copolymer chain with carboxyl groups (COOH) in another, which may involve hydrogen bonds and dipole-dipole interactions. Overall, these strong intermolecular forces lock the copolymer chains in situ, thus hindering fiberization.

[0111] Water molecules disrupt the electrostatic attraction between copolymer chains, interacting with hydrophilic groups within the copolymer chains and forming new hydrogen bonds with these groups. This interaction reduces the affinity of functional groups between copolymer chains. For example, hydrogen bonding interactions may occur between a carboxyl group in one copolymer chain and a water molecule, rather than with a nitrile group in another copolymer chain. This disruption weakens the intermolecular interactions between copolymer chains, allowing them to slide against each other under shear forces, leading to fibrosis. Therefore, the presence of some water in the electrode material mixture is preferred.

[0112] As described above, the copolymer readily undergoes fibrosis in the presence of water. Various methods are known in the art for measuring polymer fibrosis, including the fibrosis measurement method disclosed in the Examples section. In some embodiments, when using this fibrosis measurement method, the copolymer can be stretched to a height of 20-40 cm. In some embodiments, the degree of fibrosis of the copolymer measured using this fibrosis measurement method is approximately 20 cm to approximately 40 cm, approximately 22 cm to approximately 40 cm, approximately 24 cm to approximately 40 cm, approximately 26 cm to approximately 40 cm, approximately 28 cm to approximately 40 cm, approximately 30 cm to approximately 40 cm, approximately 32 cm to approximately 40 cm, approximately 34 cm to approximately 40 cm, approximately 20 cm to approximately 35 cm, approximately 22 cm to approximately 35 cm, approximately 24 cm to approximately 35 cm, approximately 26 cm to approximately 35 cm, approximately 28 cm to approximately 35 cm, or approximately 30 cm to approximately 35 cm.

[0113] In some embodiments, the degree of fiberization of the copolymer, as measured using the fiberization measurement method, is less than 40 cm, less than 39 cm, less than 38 cm, less than 37 cm, less than 36 cm, less than 35 cm, less than 34 cm, less than 33 cm, less than 32 cm, less than 31 cm, less than 30 cm, less than 28 cm, less than 26 cm, less than 24 cm, or less than 22 cm. In some embodiments, the degree of fiberization of the copolymer, as measured using the fiberization measurement method, is greater than 20 cm, greater than 21 cm, greater than 22 cm, greater than 23 cm, greater than 24 cm, greater than 25 cm, greater than 26 cm, greater than 27 cm, greater than 28 cm, greater than 29 cm, greater than 30 cm, greater than 32 cm, greater than 34 cm, greater than 36 cm, or greater than 38 cm.

[0114] The copolymerization mixture already contains water, meaning that theoretically, the post-reaction mixture can be directly used to prepare electrode material mixtures. However, surprisingly, when using the post-reaction mixture to prepare equivalent electrode material mixtures, the electrode components cannot achieve uniform dispersion within the mixture. The electrode components either exhibit poor homogeneity within the mixture or require significantly prolonged mixing times to achieve an acceptable level of uniformity. Even so, the achieved uniformity level is still inferior to that obtained by premixing dried electrode components, including a dry binder material. Therefore, the present invention requires the use of a dry binder material obtained by drying the post-reaction mixture, and premixing it with other electrode components as described above to ensure uniform distribution of the electrode components within the electrode material mixture. Subsequently, in some embodiments, an aqueous solvent is added to the premix, and the premix and water are homogenized to form the electrode material mixture.

[0115] In some embodiments, the aqueous solvent is water. In some embodiments, the aqueous solvent is selected from the group consisting of tap water, bottled water, purified water, pure water, distilled water, deionized water (DI water), heavy water (D2O), and combinations thereof. It is particularly important to note that the aqueous solvent preferably does not contain any trace components, because the fibrous properties of the copolymer depend on the interaction between the copolymer and water. It has been found that the presence of trace components in the aqueous solvent of the electrode material mixture can adversely affect the fibrousization of the copolymer. Therefore, in some embodiments, the aqueous solvent in the electrode material mixture contains no trace components other than water.

[0116] In some embodiments, the minor components include alcohols, lower aliphatic ketones, lower alkyl acetates, and combinations thereof. Some non-limiting examples of alcohols include C1-C4 alcohols, such as methanol, ethanol, isopropanol, n-propanol, tert-butanol, n-butanol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, ethylene glycol, propylene glycol, glycerol, and combinations thereof. Some non-limiting examples of lower aliphatic ketones include acetone, dimethyl ketone, methyl ethyl ketone (MEK), and combinations thereof. Some non-limiting examples of lower alkyl acetates include ethyl acetate (EA), isopropyl acetate, propyl acetate, butyl acetate (BA), and combinations thereof. Other non-limiting examples of minor components include 1,4-dioxane, diethyl ether, methyl tert-butyl ether, cyclopentyl methyl ether, tetrahydrofuran (THF), 2-methyltetrahydrofuran, acetonitrile, dimethyl sulfoxide (DMSO), sulfolane, nitromethane, propylene carbonate, ethylene carbonate, dimethyl carbonate, pyridine, acetaldehyde, formic acid, acetic acid, propionic acid, butyric acid, γ-valeronolactone (GVL), furfuryl alcohol, methyl lactate, ethyl lactate, diethanolamine, dimethylacetamide (DMAc), dimethylformamide (DMF), N-methylpyrrolidone (NMP), and dihydroglucosidone (Cyrene). ™ ), N,N'-dimethylpropenyl urea (DMPU) and isosorbide dimethyl ether (DMI).

[0117] In the electrode material mixture disclosed in this invention, the copolymer, combined with water in a specific proportion, readily undergoes fibrosis and binds the various electrode components together. The water-to-polymer ratio is crucial for the fibrosis process. Insufficient water leads to strong interactions between copolymer chains, thus hindering fibrosis. Conversely, excess water means that the copolymer chains primarily interact with water molecules, and the intermolecular interactions between copolymer chains are reduced to a level insufficient for fibrosis. The amount of water added is not high; therefore, the water present is sufficient to promote the fibrosis of the copolymer without causing side reactions such as degradation of the active material. Nevertheless, the relatively low liquid content is essential for achieving proper dispersion of the electrode components, adhesion of the binder material to other electrode components, and subsequent processing steps in battery manufacturing, as it plays a key role in promoting the adhesion and integration of electrode components while ensuring the desired properties of the electrode material mixture.

[0118] In some embodiments, based on the total weight of the electrode material mixture, the liquid content of the electrode material mixture is, by weight, about 5% to about 22%, about 8% to about 22%, about 10% to about 22%, about 12% to about 22%, about 15% to about 22%, about 18% to about 22%, about 20% to about 22%, about 5% to about 20%, about 8% to about 20%, about 10% to about 20%, about 12% to about 20%, about 15% to about 20%, about 18% to about 20%, about 5% to about 18%, about 8% to about 18%, about 10% to about 18%, about 12% to about 18%, about 15% to about 18%, about 5% to about 15%, about 8% to about 15%, about 10% to about 15%, about 12% to about 15%, about 5% to about 12%, about 8% to about 12%, about 10% to about 12%, about 5% to about 10%, about 8% to about 10%, or about 5% to about 8%. In some embodiments, based on the total weight of the electrode material mixture, the liquid content of the electrode material mixture is less than 22%, less than 20%, less than 18%, less than 15%, less than 12%, less than 10%, or less than 8% by weight. In some embodiments, based on the total weight of the electrode material mixture, the liquid content of the electrode material mixture is greater than 5%, greater than 8%, greater than 10%, greater than 12%, greater than 15%, greater than 18%, or greater than 20% by weight.

[0119] Studies have found that to maintain good fiberization properties, the liquid content must be increased with increasing weight-average molecular weight of the copolymer. Therefore, within the range of liquid content in electrode material mixtures, if the copolymer has a relatively low weight-average molecular weight, the liquid content of the electrode material mixture should tend towards the lower limit of the disclosed range. Conversely, if the copolymer has a relatively high weight-average molecular weight, the liquid content of the electrode material mixture should tend towards the upper limit of the disclosed range.

[0120] In some embodiments, based on the total weight of the solid portion of the electrode material mixture, the proportion of the copolymer in the electrode material mixture is, by weight, about 2% to about 10%, 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 8% to about 10%, about 9% to about 10%, about 2% to about 9%, about 3% to about 9%, about 4% to about 9%, about 5% to about 9%, about 6% to about 9%, about 7% to about 9%, or about 8%. From approximately 9%, approximately 2% to approximately 8%, approximately 3% to approximately 8%, approximately 4% to approximately 8%, approximately 5% to approximately 8%, approximately 6% to approximately 8%, approximately 7% to approximately 8%, approximately 2% to approximately 7%, approximately 3% to approximately 7%, approximately 4% to approximately 7%, approximately 5% to approximately 7%, approximately 6% to approximately 7%, approximately 2% to approximately 6%, approximately 3% to approximately 6%, approximately 4% to approximately 6%, approximately 5% to approximately 6%, approximately 2% to approximately 5%, approximately 3% to approximately 5%, approximately 4% to approximately 5%, approximately 2% to approximately 4%, approximately 3% to approximately 4%, or approximately 2% to approximately 3%.

[0121] In some embodiments, based on the total weight of the solid portion of the electrode material mixture, the proportion of copolymers in the electrode material mixture is less than 10%, less than 9%, less than 8%, less than 7%, less than 6%, less than 5%, less than 4%, or less than 3% by weight. In some embodiments, based on the total weight of the solid portion of the electrode material mixture, the proportion of copolymers in the electrode material mixture is greater than 2%, greater than 3%, greater than 4%, greater than 5%, greater than 6%, greater than 7%, greater than 8%, or greater than 9% by weight.

[0122] In some embodiments, based on the total weight of the solid portion of the electrode material mixture, the proportion of the conductive agent in the electrode material mixture is, by weight, about 1% to about 10%, about 2% to about 10%, 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 8% to about 10%, about 9% to about 10%, about 1% to about 9%, about 2% to about 9%, about 3% to about 9%, about 4% to about 9%, about 5% to about 9%, about 6% to about 9%, about 7% to about 9%, about 8% to about 9%, about 1% to about 8%, or about 2% to about 8%. Approximately 3% to approximately 8%, approximately 4% to approximately 8%, approximately 5% to approximately 8%, approximately 6% to approximately 8%, approximately 7% to approximately 8%, approximately 1% to approximately 7%, approximately 2% to approximately 7%, approximately 3% to approximately 7%, approximately 4% to approximately 7%, approximately 5% to approximately 7%, approximately 6% to approximately 7%, approximately 1% to approximately 6%, approximately 2% to approximately 6%, approximately 3% to approximately 6%, approximately 4% to approximately 6%, approximately 5% to approximately 6%, approximately 1% to approximately 5%, approximately 2% to approximately 5%, approximately 3% to approximately 5%, approximately 4% to approximately 5%, approximately 1% to approximately 4%, approximately 2% to approximately 4%, approximately 3% to approximately 4%, approximately 1% to approximately 3%, approximately 2% to approximately 3%, or approximately 1% to approximately 2%.

[0123] In some embodiments, based on the total weight of the solid portion of the electrode material mixture, the proportion of the conductive agent in the electrode material mixture is less than 10%, less than 9%, less than 8%, less than 7%, less than 6%, less than 5%, less than 4%, less than 3%, or less than 2% by weight. In some embodiments, based on the total weight of the solid portion of the electrode material mixture, the proportion of the conductive agent in the electrode material mixture is greater than 1%, greater than 2%, greater than 3%, greater than 4%, greater than 5%, greater than 6%, greater than 7%, greater than 8%, or greater than 9% by weight.

[0124] In some embodiments, based on the total weight of the solid portion of the electrode material mixture, the proportion of electrode active material in the electrode material mixture is, by weight, approximately 80% to approximately 99%, approximately 82% to approximately 99%, approximately 84% to approximately 99%, approximately 86% to approximately 99%, approximately 88% to approximately 99%, approximately 90% to approximately 99%, approximately 92% to approximately 99%, approximately 94% to approximately 99%, approximately 96% to approximately 99%, approximately 80% to approximately 96%, approximately 82% to approximately 96%, approximately 84% to approximately 96%, approximately 86% to approximately 96%, approximately 88% to approximately 96%, approximately 90% to approximately 96%, approximately 92% to approximately 96%, approximately 94% to approximately 96%, approximately 80% to approximately 94%, approximately 82% to approximately 94%, and approximately 84% to approximately 94%. %, about 86% to about 94%, about 88% to about 94%, about 90% to about 94%, about 92% to about 94%, about 80% to about 92%, about 82% to about 92%, about 84% to about 92%, about 86% to about 92%, about 88% to about 92%, about 90% to about 92%, about 80% to about 90%, about 82% to about 90%, about 84% to about 90%, about 86% to about 90%, about 88% to about 90%, about 80% to about 88%, about 82% to about 88%, about 84% to about 88%, about 86% to about 88%, about 80% to about 86%, about 82% to about 86%, about 84% to about 86%, about 80% to about 84%, about 82% to about 84%, or about 80% to about 82%.

[0125] In some embodiments, based on the total weight of the solid portion of the electrode material mixture, the proportion of electrode active material in the electrode material mixture is less than 99%, less than 98%, less than 96%, less than 94%, less than 92%, less than 90%, less than 88%, less than 86%, less than 84%, or less than 82% by weight. In some embodiments, based on the total weight of the solid portion of the electrode material mixture, the proportion of electrode active material in the electrode material mixture is greater than 80%, greater than 82%, greater than 84%, greater than 86%, greater than 88%, greater than 90%, greater than 92%, greater than 94%, greater than 96%, or greater than 98% by weight.

[0126] The present invention can use any homogenizer capable of promoting uniform distribution of the premix in water. In some embodiments, the homogenizer is a screw mixer, mill, stirred mixer, or planetary mixer.

[0127] There is no particular limitation on the mixing time of the premix and water for homogenization, but the copolymer must be sufficiently fibrous to bind all electrode components together and ensure a uniform distribution of the electrode material mixture at the end of the mixing process. Therefore, the mixing time must be sufficiently long. In some embodiments, the homogenization time after adding the water to the premix is ​​from about 1 minute to about 6 hours. In some embodiments, the homogenization time for preparing the electrode material mixture after adding all electrode components is less than 6 hours, less than 5 hours, less than 4 hours, less than 3 hours, less than 2 hours, less than 60 minutes, less than 50 minutes, less than 40 minutes, less than 30 minutes, less than 20 minutes, less than 15 minutes, less than 10 minutes, less than 5 minutes, less than 4 minutes, less than 3 minutes, or less than 2 minutes. In some embodiments, after the water is added to the premix, the homogenization time exceeds 1 minute, 2 minutes, 3 minutes, 4 minutes, 5 minutes, 10 minutes, 15 minutes, 20 minutes, 30 minutes, 40 minutes, 50 minutes, 60 minutes, 2 hours, 3 hours, 4 hours, or 5 hours.

[0128] Maintaining an appropriate temperature during the homogenization of the premix and water helps promote efficient mixing and enhances the homogeneity and integration of electrode components in the electrode material mixture. Therefore, the homogenizer can be equipped with a temperature control system to homogenize the premix and water at high temperatures. In some embodiments, the premix and water are homogenized at temperatures from about 20°C to about 50°C. In some embodiments, the premix and water are homogenized at temperatures below 50°C, below 45°C, below 40°C, below 35°C, below 30°C, or below 25°C. In some embodiments, the premix and water are homogenized at temperatures above 20°C, above 25°C, above 30°C, above 35°C, above 40°C, or above 45°C.

[0129] During the homogenization of the premix and water, the rotational speed of the homogenizer's rotating elements can be customized within a specified range, where the homogenizer can be a screw mixer, a stirring mixer, or a planetary mixer. By adjusting the rotational speed of the rotating elements, the intensity of mixing the premix and water can be changed. Higher speeds achieve more vigorous mixing, while lower speeds provide a gentler mixing process. This flexibility allows for precise control and refinement of mixing conditions according to the specific requirements of the electrode material mixture. In some embodiments, the rotational speed of each rotating element in the homogenizer used to homogenize the premix and water can be independently the same, higher, or lower than the speed used during the homogenization of the electrode components when preparing the premix.

[0130] It is noteworthy that the homogenizer disclosed in this invention for homogenizing the premix and water does not require high shear force, unlike conventional fluorinated binder materials such as PVDF when mixed with other electrode components. In the latter case, considerable force is required to promote the fiberization of the binder. This distinction is crucial because the absence of high shear force not only simplifies the mixing process but also reduces the risk of damaging the electrode components. The binder material readily undergoes fiberization without excessive force, enabling a more efficient and controllable production method that ensures optimal dispersion and integration of the binder material within the electrode material mixture.

[0131] In some embodiments, after homogenization, the electrode material mixture is coated or calendered to form a self-supporting electrode layer. A release film serves as a temporary support for the electrode material mixture. Subsequently, the self-supporting electrode layer is laminated onto the current collector and pressed together to form the final electrode structure. In some embodiments, the formation of the self-supporting electrode layer can be accomplished using a molding press, a rolling mill, or an extruder. In some embodiments, the molding press is a tablet press. In some embodiments, the extruder is a screw extruder. The lamination step can be accomplished by applying pressure to bond the self-supporting electrode layer to the current collector. This step ensures a strong adhesion between the electrode layer and the current collector. Pressure can be applied using a laminator, a hydraulic press, or other suitable equipment. The pressure and pressing time can vary depending on the materials used and their specific requirements. In some cases, the electrode may require heat treatment, such as drying or annealing, to improve the stability and performance of the electrode. The freestanding electrode layer can then be successfully applied to the current collector to form a cohesive and integrated electrode structure.

[0132] A current collector is used to collect electrons generated by the electrochemical reaction of a cathode active material, or to provide electrons required for an 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 covered 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 a conductive material, and the intermediate layer comprises an insulating material or another conductive material; for example, a plastic substrate coated with a metal film on both sides. In 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 comprises a structure of three or more layers.

[0133] In some embodiments, the conductive layer may be coated onto the current collector to improve its conductivity. In some embodiments, the conductive layer comprises a material selected from the group consisting of carbon, carbon black, graphite, expanded graphite, graphene, graphene nanosheets, carbon fibers, carbon nanofibers, graphitized carbon sheets, carbon nanotubes, carbon nanotubes, activated carbon, mesoporous carbon, and combinations thereof. In some embodiments, the conductive layer does not comprise carbon, carbon black, graphite, expanded graphite, graphene, graphene nanosheets, carbon fibers, carbon nanofibers, graphitized carbon sheets, carbon nanotubes, carbon nanotubes, activated carbon, or mesoporous carbon.

[0134] In some embodiments, the thickness of the conductive layer is from about 0.5 μm to about 5.0 μm. The thickness of the conductive layer affects the volume occupied by the current collector within the battery and the amount of electrode active material required, thereby affecting the battery capacity.

[0135] In some embodiments, the thickness of the conductive layer on the current collector is about 0.5 μm to about 4.5 μm, about 1.0 μm to about 4.0 μm, about 1.0 μm to about 3.5 μm, about 1.0 μm to about 3.0 μm, about 1.0 μm to about 2.5 μm, about 1.0 μm to about 2.0 μm, about 1.1 μm to about 2.0 μm, about 1.2 μm to about 2.0 μm, about 1.5 μm to about 2.0 μm, about 1.8 μm to about 2.0 μm, about 1.0 μm to about 1.8 μm, about 1.2 μm to about 1.8 μm, about 1.5 μm to about 1.8 μm, about 1.0 μm to about 1.5 μm, or about 1.2 to about 1.5 μm. In some embodiments, the thickness of the conductive layer on the current collector is less than 4.5 µm, less than 4.0 µm, less than 3.5 µm, less than 3.0 µm, less than 2.5 µm, less than 2.0 µm, less than 1.8 µm, less than 1.5 µm, or less than 1.2 µm. In some embodiments, the thickness of the conductive layer on the current collector is greater than 1.0 µm, greater than 1.2 µm, greater than 1.5 µm, greater than 1.8 µm, greater than 2.0 µm, greater than 2.5 µm, greater than 3.0 µm, or greater than 3.5 µm.

[0136] The thickness of the current collector affects its volumetric size within the battery, thus impacting the battery's energy density. In some embodiments, the current collector thickness is from about 5 μm to about 30 μm. In other embodiments, the current collector thickness is from about 5 μm to about 20 μm, from about 5 μm to about 15 μm, from about 10 μm to about 30 μm, from about 10 μm to about 25 μm, or from about 10 μm to about 20 μm.

[0137] After the self-supporting electrode layer is coated onto the current collector surface, it can be dried. During the drying process, the moisture previously present between the copolymer chains is removed. This moisture removal leads to strong intermolecular interactions between the different copolymer chains. These intermolecular interactions act as anchors, fixing the copolymer chains in their relative positions and preventing further fibrillation. Furthermore, the copolymer chains form bridging connections between the electrode component particles and with the current collector. Due to the random orientation of the copolymer chains, a network structure is formed, which, combined with the bridging connections between the electrode component particles, ensures close contact between the particles, resulting in a continuous and uniform electrode layer. This close contact reduces interfacial resistance and promotes efficient electron transport within the electrode. Moreover, the electrode layer adheres firmly to the current collector, ensuring mechanical stability and integrity.

[0138] Some non-limiting examples of equipment that can be used for heating and drying coated films include intermittent drying ovens, conveyor belt drying ovens, and microwave drying ovens. Some non-limiting examples of conveyor belt drying ovens include conveyor belt hot air drying ovens, conveyor belt resistance drying ovens, conveyor belt induction drying ovens, and conveyor belt microwave drying ovens. These drying ovens offer different heating mechanisms and can be used according to specific requirements. There are no particular limitations on the conditions used for heating and drying coated films, but after the heating and drying process is completed, the coated film should be firmly fixed to the current collector and should not be deformed or delaminated. Alternatively, laminated electrodes consisting of separate electrode layers and current collectors can be dried using heated rollers. Therefore, the temperature should be high enough to complete the drying process within a reasonable time range. Simultaneously, the temperature should be low enough to prevent degradation of the electrode components in the resulting electrode layer and to minimize the risk of uneven heating, thereby avoiding electrode deformation or delamination.

[0139] In some embodiments, the temperature for heating and drying the laminated electrode is from about 30˚C to about 150˚C, from about 30˚C to about 100˚C, from about 50˚C to about 150˚C, or from about 50˚C to about 100˚C.

[0140] In some embodiments, the temperature for heating and drying the laminated electrode is below 150˚C, below 140˚C, below 130˚C, below 120˚C, below 110˚C, below 100˚C, below 90˚C, below 80˚C, below 70˚C, below 60˚C, below 50˚C, below 40˚C, or below 30˚C. In some embodiments, the temperature for heating and drying the coating film on the current collector is above 30˚C, above 40˚C, above 50˚C, above 60˚C, above 70˚C, above 80˚C, above 90˚C, above 100˚C, above 110˚C, above 120˚C, above 130˚C, above 140˚C, or above 150˚C.

[0141] In some embodiments, the drying time of the laminated electrode is from 10 seconds to 60 minutes. In some embodiments, the drying time of the laminated electrode is from 1 minute to 60 minutes, 1 minute to 50 minutes, 1 minute to 40 minutes, 1 minute to 30 minutes, 1 minute to 20 minutes, 1 minute to 10 minutes, or 1 minute to 5 minutes. In some embodiments, the drying time of the laminated electrode exceeds 10 seconds, exceeds 20 seconds, exceeds 30 seconds, exceeds 40 seconds, exceeds 50 seconds, exceeds 1 minute, exceeds 2 minutes, exceeds 3 minutes, exceeds 4 minutes, exceeds 5 minutes, exceeds 10 minutes, exceeds 15 minutes, exceeds 20 minutes, exceeds 25 minutes, exceeds 30 minutes, exceeds 40 minutes, or exceeds 50 minutes. In some implementations, the drying time of the laminated electrode is less than 50 minutes, less than 40 minutes, less than 30 minutes, less than 20 minutes, less than 10 minutes, less than 5 minutes, less than 4 minutes, less than 3 minutes, less than 2 minutes, less than 1 minute, less than 50 seconds, less than 40 seconds, less than 30 seconds, or less than 20 seconds.

[0142] In some embodiments, after heating and drying, the electrodes are compressed to increase their density. The proportion of copolymers in the electrode layer is the same as the proportion of copolymers in the electrode material mixture described above. Similarly, the proportion of conductive agent and electrode active material in the electrode layer is also the same as the corresponding proportion of conductive agent and electrode active material in the electrode material mixture described above. In summary, surprisingly, due to the presence of copolymers in the electrode layer, it is possible to make a thicker electrode layer than conventional electrode layers. This increased electrode layer thickness, in turn, increases the overall energy density of the battery.

[0143] Regardless of whether the electrode is compressed, in some embodiments, the thickness of the electrode layer is about 20 μm to about 400 μm, about 50 μm to about 400 μm, about 100 μm to about 400 μm, about 150 μm to about 400 μm, about 200 μm to about 400 μm, about 250 μm to about 400 μm, or about 300 μm to about 400 μm. In some embodiments, regardless of whether the electrode is compressed, the thickness of the electrode layer is greater than 20 μm, greater than 30 μm, greater than 40 μm, greater than 50 μm, greater than 100 μm, greater than 150 μm, greater than 200 μm, greater than 250 μm, greater than 300 μm, or greater than 350 μm. In some implementations, the thickness of the electrode layer is less than 400 μm, less than 350 μm, less than 300 μm, less than 250 μm, less than 200 μm, less than 150 μm, less than 100 μm, less than 50 μm, or less than 30 μm, regardless of whether the electrode is compressed.

[0144] Regardless of whether the electrodes are compressed, in some embodiments, the surface density of the electrode layer is approximately 1 mg / cm² to approximately 50 mg / cm², approximately 3 mg / cm² to approximately 50 mg / cm², approximately 5 mg / cm² to approximately 50 mg / cm², approximately 10 mg / cm² to approximately 50 mg / cm², approximately 15 mg / cm² to approximately 50 mg / cm², approximately 20 mg / cm² to approximately 50 mg / cm², approximately 30 mg / cm² to approximately 50 mg / cm², approximately 40 mg / cm² to approximately 50 mg / cm², approximately 1 mg / cm² to approximately 40 mg / cm², approximately 1 mg / cm² to approximately 30 mg / cm², approximately 5 mg / cm² to approximately 30 mg / cm², approximately 10 mg / cm² to approximately 30 mg / cm², and approximately 15 mg / cm². 2 Approximately 30 mg / cm 2 Approximately 20 mg / cm 2 Approximately 30 mg / cm 2 Approximately 1 mg / cm² to approximately 20 mg / cm² 2 Approximately 5 mg / cm 2 Approximately 20 mg / cm 2 Approximately 10 mg / cm 2 Approximately 20 mg / cm², approximately 1 mg / cm² 2 Approximately 15 mg / cm 2 Approximately 3 mg / cm 2 Approximately 15 mg / cm 2 Approximately 5 mg / cm 2 Approximately 15 mg / cm 2 or approximately 10 mg / cm 2 Approximately 15 mg / cm 2 .

[0145] Regardless of whether the electrodes are compressed, in some embodiments, the surface density of the electrode layer is less than 50 mg / cm³. 2 Less than 45 mg / cm 2 Less than 40 mg / cm 2 Less than 35 mg / cm 2 Less than 30 mg / cm 2 Less than 25 mg / cm 2 Less than 20 mg / cm 2 Less than 15 mg / cm 2 Less than 10 mg / cm 2 Less than 5 mg / cm 2 or less than 3 mg / cm2 Regardless of whether the electrodes are compressed, in some embodiments, the surface density of the electrode layer is greater than 1 mg / cm³. 2 Greater than 3 mg / cm 2 Greater than 5 mg / cm 2 Greater than 10 mg / cm 2 Greater than 15 mg / cm 2 Greater than 20 mg / cm 2 Greater than 25 mg / cm 2 Greater than 30 mg / cm 2 greater than 35 mg / cm 2 >40 mg / cm 2 or greater than 45 mg / cm 2 .

[0146] Regardless of whether the electrodes are compressed, in some embodiments, the density of the electrode layer is about 0.5 g / cm³ to about 7.5 g / cm³, about 1 g / cm³ to about 7.5 g / cm³, about 1.5 g / cm³ to about 7.5 g / cm³, about 2 g / cm³ to about 7.5 g / cm³, about 2.5 g / cm³ to about 7.5 g / cm³, about 3 g / cm³ to about 7.5 g / cm³, about 3.5 g / cm³ to about 7.5 g / cm³, about 4 g / cm³ to about 7.5 g / cm³, about 4.5 g / cm³ to about 7.5 g / cm³, about 0.5 g / cm³ to about 5.5 g / cm³, about 1 g / cm³ to about 5.5 g / cm³, and about 1.5 g / cm³. 3 Approximately 5.5 g / cm 3 Approximately 2 g / cm 3 Approximately 5.5 g / cm 3 Approximately 2.5g / cm 3 Approximately 5.5 g / cm 3 Approximately 0.5 g / cm 3 To approximately 2.5 g / cm 3 Approximately 1 g / cm 3 To approximately 2.5 g / cm 3 or approximately 1.5 g / cm³ 3 To approximately 2.5 g / cm 3 Regardless of whether the electrodes are compressed, in some embodiments, the density of the electrode layer is less than 7.5 g / cm³. 3 Less than 6.5 g / cm 3 Less than 6 g / cm 3 Less than 5.5 g / cm 3 Less than 5 g / cm3 Less than 4.5 g / cm 3 Less than 4 g / cm 3 Less than 3.5 g / cm 3 Less than 3 g / cm 3 Less than 2.5 g / cm 3 Less than 2 g / cm 3 Less than 1.5 g / cm 3 or less than 1 g / cm 3 Regardless of whether the electrodes are compressed, in some embodiments, the density of the electrode layer is greater than 0.5 g / cm³. 3 Greater than 1 g / cm 3 Greater than 1.5 g / cm 3 Greater than 2 g / cm 3 Greater than 2.5 g / cm 3 Greater than 3 g / cm 3 Greater than 3.5 g / cm 3 Greater than 4 g / cm 3 Greater than 4.5 g / cm 3 Greater than 5 g / cm 3 or greater than 5.5 g / cm 3 .

[0147] Furthermore, as described above, the electrode prepared using the electrode material mixture disclosed in this invention exhibits strong adhesion between its electrode layer and the current collector. The electrode layer must possess good peel strength to ensure its firm attachment to the current collector and prevent delamination or separation. Maintaining a strong bond between the electrode layer and the current collector is crucial, as it significantly affects the mechanical stability of the electrode and the performance of the battery. Therefore, the electrode should possess sufficient peel strength to withstand the harsh conditions encountered during battery manufacturing and must be able to withstand various handling and assembly steps without separation or weakening of the bonding force between the electrode layer and the current collector. Delamination or separation of the electrode layer can lead to battery performance problems and shortened lifespan.

[0148] Regardless of whether the electrode is compressed, in some embodiments, the peel strength between the current collector and the electrode layer is about 1.0 N / cm to about 8.0 N / cm, about 1.0 N / cm to about 6.0 N / cm, about 1.0 N / cm to about 5.0 N / cm, about 1.0 N / cm to about 4.0 N / cm, about 1.0 N / cm to about 3.0 N / cm, about 1.0 N / cm to about 2.5 N / cm, about 1.0 N / cm to about 2.0 N / cm, about 1.2 N / cm to about 3.0 N / cm, about 1.2 N / cm to about 2.5 N / cm, about 1.2 N / cm to about 2.0 N / cm, about 1.5 N / cm to about 3.0 N / cm, about 1.5 N / cm to about 2.5 N / cm, about 1.5 N / cm to about 2.0 N / cm, about 1.8 N / cm to about 3.0 N / cm, and about 1.8 N / cm to about 2.5 N / cm. N / cm, about 2.0 N / cm to about 6.0 N / cm, about 2.0 N / cm to about 5.0 N / cm, about 2.0 N / cm to about 3.0 N / cm, about 2.0 N / cm to about 2.5 N / cm, about 2.2 N / cm to about 3.0 N / cm, about 2.5 N / cm to about 3.0 N / cm, about 3.0 N / cm to about 8.0 N / cm, about 3.0 N / cm to about 6.0 N / cm, or about 4.0 N / cm to about 6.0 N / cm.

[0149] Regardless of whether the electrode is compressed, in some embodiments, the peel strength between the current collector and the electrode layer is greater than 1.0 N / cm, 1.2 N / cm, 1.5 N / cm, 2.0 N / cm, 2.2 N / cm, 2.5 N / cm, 3.0 N / cm, 3.5 N / cm, 4.0 N / cm, 4.5 N / cm, 5.0 N / cm, 5.5 N / cm, 6.0 N / cm, 6.5 N / cm, or 7.0 N / cm. Regardless of whether the electrode is compressed, in some embodiments, the peel strength between the current collector and the electrode layer is less than 8.0 N / cm, less than 7.5 N / cm, less than 7 N / cm, less than 6.5 N / cm, less than 6.0 N / cm, less than 5.5 N / cm, less than 5.0 N / cm, less than 4.5 N / cm, less than 4.0 N / cm, less than 3.5 N / cm, less than 3.0 N / cm, less than 2.8 N / cm, less than 2.5 N / cm, less than 2.2 N / cm, less than 2.0 N / cm, less than 1.8 N / cm, or less than 1.5 N / cm. By ensuring that the electrode has sufficient peel strength, the manufacturer can obtain a reliable and stable electrode structure.

[0150] Once the electrode is manufactured, it can be assembled with the diaphragm and the corresponding counter electrode to form an electrode assembly. The choice of counter electrode depends on whether the electrode itself is used as a cathode or anode.

[0151] The copolymers disclosed in this invention are readily fibrous, meaning that when the electrode material mixtures are manufactured using the methods disclosed in this invention, the resulting electrode layers exhibit strong bonding between their constituent components and strong adhesion to the current collector. This ensures good integration and strong bonding of the electrode components, preventing delamination or separation, and even allows for the use of thicker electrode layers, thereby increasing battery energy density. Furthermore, such electrodes can be easily recycled without resorting to environmentally harmful methods. The electrode material mixture also has a low water content, thereby minimizing degradation of the cathode active material due to water reaction and the resulting loss of battery performance. By employing the methods of this invention, electrode manufacturing processes can be significantly improved without sacrificing battery electrochemical performance.

[0152] 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.

[0153] Although the invention has been described in conjunction with a limited number of embodiments, specific features of one embodiment should not be attributed to other embodiments of the invention. In some embodiments, the method may include numerous steps not mentioned in the invention. In other embodiments, the method does not include or substantially does not contain any steps not listed in the invention. Variations and modifications are possible with the described embodiments. The appended claims are intended to cover all such modifications and variations that fall within the scope of the invention. Example

[0154] The peel strength of the electrode layer was measured using a tensile testing machine (DZ-106A, from Dongguan Zhonghao Testing Equipment Co., Ltd., China). This test measures the average force required to peel the electrode layer from the current collector at an angle of 180˚, expressed in Newtons (N). The average roughness depth (R) of the current collector is also measured. z The thickness is 2 μm. A 18 mm wide and 20 mm long strip of adhesive tape (3M; USA; model 810) is adhered to the surface of the electrode layer. The electrode strip is clamped in the testing machine, the tape is folded 180˚ and placed in a movable fixture, and stretched at a peel rate of 200 mm / min at room temperature. The maximum peel force measured is considered the peel strength. The measurement is repeated three times to obtain the average value.

[0155] The degree of fiberization of the copolymer can be measured using the apparatus disclosed in CN 216978992 U via the following steps: The solids content of the dried binder composition (i.e., the filtered sixth suspension) is normalized to 12%, and then poured into a container to a depth of 40 mm. A 2 mm diameter needle is then immersed in the binder composition for 10 mm, left to stand for 30 seconds, and then lifted at a constant speed of 5 mm / s. The degree of fiberization of the copolymer can be quantified by the maximum height to which the needle can pull the copolymer without breaking it.

[0156] The solids content of the binder composition or electrode material mixture is calculated based on the mass change of the binder composition or electrode material mixture before and after drying. Approximately 1 g of the binder composition or electrode material mixture is weighed into a weighing bottle and dried in a vacuum dryer at 110 ± 5˚C and -0.09 MPa for at least 5 hours. After cooling in the dryer for approximately 15 minutes, its mass is measured. The mass difference of the binder composition / electrode material mixture before and after drying is obtained, and the solids content of the binder composition, dry electrode mixture, or electrode slurry is calculated using the following formula: Where x can refer to the binder composition or electrode material mixture.

[0157] The weight-average molecular weight of the copolymer in the binder composition was measured by gel permeation chromatography. First, the dried binder material was dissolved in dimethylformamide at room temperature. After dissolution, the solution was filtered through a 0.45 μm pore size filter to prepare the test sample. A calibration curve was established using polystyrene standards, and the weight-average molecular weight of the copolymer was calculated based on the curve. The obtained test sample was analyzed using an Agilent PLgel 5 μm MIXED-C column at a flow rate of 1 ml / min and a sample weight of 2 mg. A Waters 2414 refractive index (RI) detector was used, and the detection temperature was 35˚C.

[0158] Example 1 A) Preparation of adhesive materials 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.

[0159] Add 24.78 g of acrylic acid to the first suspension. Stir the mixture further at 80 rpm for 30 minutes to obtain the second suspension.

[0160] An acrylamide solution was prepared by dissolving 28.76 g of acrylamide in 10 g of deionized water. 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.

[0161] Add 13.95 g of acrylonitrile to the third suspension. Stir the mixture further at 80 rpm for 10 minutes to obtain the fourth suspension.

[0162] Subsequently, 0.015 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 0.0075 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 200 rpm at 55˚C for 24 hours to obtain the fifth suspension.

[0163] After complete reaction, the temperature of the fifth suspension was lowered to 25˚C. 3.72 g of NaOH was dissolved in 200 g of deionized water, and the entire sodium hydroxide solution was added dropwise to the fifth suspension to adjust the pH to 7.3, obtaining the sixth suspension. The sixth suspension was filtered using a 200 µm nylon mesh. The solids content of the filtered sixth suspension was 11.59 wt.%.

[0164] The filtered sixth suspension was dried overnight at 60˚C in a vacuum dryer, and then ground into a powdered dry binder material using a mortar and pestle. The binder composition has a weight-average molecular weight of 550,000 g / mol, and the copolymer is capable of being fiberized to 32 cm.

[0165] B) Preparation of the positive electrode 0.21 kg of conductive agent (KS6; from ANR Technologies Pte. Ltd., Singapore), 0.15 kg of binder material, and 2.64 kg of NMC532 (from Shandong Tianjiao New Energy Co., Ltd., China) were sequentially added to a grounded planetary mixer and mixed at approximately 200 rpm for approximately 25 minutes to form a homogeneous, dry mixture as a premix. The premix was then fed into a screw mixer, and subsequently 0.42 kg of deionized water was added to the premix. The premix and deionized water mixture was discharged from the screw mixer to obtain a homogeneous electrode material mixture. The mixing process in the screw mixer took approximately 5 minutes.

[0166] A homogenized electrode material mixture was pressed onto one side of an aluminum foil serving as a current collector using a hot press, to a thickness of 16 μm. The film coated on the aluminum foil was then vacuum-dried at approximately 60°C to form a cathode electrode layer. The electrode layer had a thickness of 76 μm and a surface density of approximately 20 mg / cm³. 2 Its density is approximately 3.3 g / cm³. 3 .

[0167] C) Preparation of the negative electrode A negative electrode slurry was prepared by mixing 93 wt.% graphite (from Shenzhen BTR New Material Group Co., Ltd.), 1 wt.% carboxymethyl cellulose (CMC, BSH-12, DKS Co. Ltd., Japan), and 3 wt.% styrene-butadiene rubber (AL-2001, NIPPON A&L INC., Japan) as binders and 3 wt.% carbon black as a conductive agent in deionized water. The resulting negative electrode slurry had a solids content of 51.5 wt.%. The slurry was coated onto one side of an 8 μm thick copper foil using a doctor blade coater. The coated slurry on the copper foil was dried at approximately 80˚C using a hot air dryer to obtain the negative electrode. The resulting electrode was then pressed to reduce the thickness of the negative electrode layer to 75 µm. The areal density of the resulting negative electrode layer was approximately 10 mg / cm².

[0168] D) Button battery assembly CR 2032 button-type lithium batteries were assembled in an argon-filled glove box. The coated cathode and anode sheets were cut into disc-shaped positive and negative electrodes, respectively. The cathode and anode were separated by a membrane, which was a ceramic-coated nonwoven fabric (MPM, Japan) microporous membrane with a thickness of approximately 25 μm. The electrode assembly was dried in a box-type resistance furnace (DZF-6020, from Shenzhen Kejing Xingguang Technology Co., Ltd., China) under vacuum at 105˚C for approximately 16 hours. After drying, the moisture content of the membrane and electrode assembly was 180 ppm.

[0169] Subsequently, under a high-purity argon atmosphere with moisture and oxygen contents of less than 3 ppm, the electrolyte was injected into the casing containing the electrodes. The electrolyte was a solution containing LiPF6 (1 M) in a 1:1:1 volume ratio mixture of ethylene carbonate (EC), ethyl methyl carbonate (EMC), and dimethyl carbonate (DMC). After injecting the electrolyte, the button cell was mechanically pressed together using a standard circular stamping tool.

[0170] E) Electrochemical Measurement The button cell was analyzed in constant current mode using a multichannel battery tester (BTS-4008-5V 50mA, from Xinwei Electronics Co., Ltd.). Initial cycling was performed between 3.0 and 4.3 V at C / 20, 25˚C, and the corresponding discharge capacity was measured. The button cell was then cycled 100 times, and the capacity retention after 100 cycles was measured. The electrochemical performance measurement results of the button cell of Example 1 are shown in Table 1 below.

[0171] Example 2: Preparation of Adhesive Materials The binder material was prepared using the same method as described in Example 1, except that the polymerization process was controlled so that the copolymer had a weight-average molecular weight of approximately 480,000 g / mol. This copolymer was capable of being fiberized to a length of 23 cm.

[0172] Example 3: Preparation of Adhesive Materials The preparation method of the binder material is the same as that described in Example 1, except that the polymerization process is controlled so that the weight-average molecular weight of the copolymer is approximately 630,000 g / mol. This copolymer can be fiberized to a length of 39 cm.

[0173] Preparation of adhesive materials in Examples 4-5, 10-12 and Comparative Examples 10-12 The preparation method of the adhesive material is the same as that described in Example 1.

[0174] Example 6 Preparation of Adhesive Material The preparation method of the binder material is the same as that described in Example 1, except that 11.09 g of sodium hydroxide is added in the preparation of the first suspension, 23.32 g of acrylic acid is added in the preparation of the second suspension, 22.29 g of acrylamide is added in the preparation of the third suspension, and 19.86 g of acrylonitrile is added in the preparation of the fourth suspension. The resulting binder material has a solid content of 11.25 wt.%, and the copolymer has a weight-average molecular weight of approximately 550,000 g / mol. This copolymer can be fiberized to a length of 26 cm.

[0175] Example 7 Preparation of adhesive materials The preparation method of the binder material is the same as that described in Example 1, except that 3.40 g of sodium hydroxide is added when preparing the first suspension, 9.48 g of acrylic acid is added when preparing the second suspension, 36.67 g of acrylamide is added when preparing the third suspension, and 19.32 g of acrylonitrile is added when preparing the fourth suspension. The resulting binder material has a solids content of 10.57 wt.%, and the copolymer has a weight-average molecular weight of approximately 550,000 g / mol. This copolymer can be fiberized to a length of 38 cm.

[0176] Example 8: Preparation of Adhesive Material The preparation method of the binder material is the same as that described in Example 1, except that 13.92 g of sodium hydroxide is added when preparing the first suspension, 28.43 g of acrylic acid is added when preparing the second suspension, 19.41 g of acrylamide is added when preparing the third suspension, and 18.25 g of acrylonitrile is added when preparing the fourth suspension. The resulting binder material has a solids content of 11.32 wt.%, and the copolymer has a weight-average molecular weight of approximately 550,000 g / mol. This copolymer can be fiberized to a length of 22 cm.

[0177] Example 9: Preparation of Adhesive Material The preparation method of the binder material is the same as that described in Example 1, except that 13.92 g of sodium hydroxide is added when preparing the first suspension, 28.43 g of acrylic acid is added when preparing the second suspension, 17.97 g of acrylamide is added when preparing the third suspension, and 12.88 g of acrylonitrile and 10.22 g of tetramethylethylene are added when preparing the fourth suspension. The resulting binder material has a solids content of 11.57 wt.%, and the copolymer has a weight-average molecular weight of approximately 550,000 g / mol. This copolymer can be fiberized to a length of 21 cm.

[0178] Example 13 Preparation of adhesive materials The adhesive material was prepared using the same method as described in Example 1, except that all acrylic acid was replaced with 34.43 g of 2-ethylacrylic acid. The resulting adhesive material had a solids content of 12.98 wt.%, a weight-average molecular weight of approximately 550,000 g / mol, and was capable of being fiberized to a length of 34 cm.

[0179] Example 14 Preparation of adhesive materials The adhesive material was prepared using the same method as described in Example 1, except that all acrylic acid was replaced with 37.18 g of vinyl sulfonic acid. The resulting adhesive material had a solids content of 13.29 wt.%, a weight-average molecular weight of approximately 550,000 g / mol, and was capable of being fiberized to a length of 29 cm.

[0180] Adhesive material of Comparative Example 1 PVDF-HFP has a weight-average molecular weight of approximately 400,000 g / mol and is used as a dry binder material.

[0181] Adhesive material of Comparative Example 2 CMC with a weight-average molecular weight of approximately 700,000 g / mol is used as a dry binder material.

[0182] Preparation of adhesive materials in Comparative Example 3 The preparation method of the binder material is the same as that described in Example 1, except that 16.35 g of sodium hydroxide is added when preparing the first suspension, 32.80 g of acrylic acid is added when preparing the second suspension, 15.10 g of acrylamide is added when preparing the third suspension, and 18.25 g of acrylonitrile is added when preparing the fourth suspension. The resulting binder material has a solid content of 11.63 wt.%, the copolymer has a weight-average molecular weight of approximately 550,000 g / mol, and the copolymer can be fiberized to 17 cm.

[0183] Comparative Example 4: Preparation of Adhesive Materials The preparation method of the binder material is the same as that described in Example 1, except that 1.38 g of sodium hydroxide is added when preparing the first suspension, 5.83 g of acrylic acid is added when preparing the second suspension, 38.11 g of acrylamide is added when preparing the third suspension, and 20.93 g of acrylonitrile is added when preparing the fourth suspension. The resulting binder material has a solid content of 10.67 wt.%, the copolymer has a weight-average molecular weight of approximately 550,000 g / mol, and the copolymer can be fiberized to 12 cm.

[0184] Comparative Example 5: Preparation of Adhesive Materials The preparation method of the binder material is the same as that described in Example 1, except that 13.92 g of sodium hydroxide (NaOH) is added when preparing the first suspension, 28.43 g of acrylic acid is added when preparing the second suspension, 5.75 g of acrylamide is added when preparing the third suspension, and 28.45 g of acrylonitrile is added when preparing the fourth suspension. The resulting binder material has a solid content of 11.18 wt.%, the copolymer has a weight-average molecular weight of approximately 550,000 g / mol, and the copolymer can be fiberized to a length of 3 cm.

[0185] Comparative Example 6: Preparation of Adhesive Materials The preparation method of the binder material is the same as that described in Example 1, except that 13.52 g of sodium hydroxide is added when preparing the first suspension, 27.70 g of acrylic acid is added when preparing the second suspension, 11.50 g of acrylamide is added when preparing the third suspension, and 17.17 g of acrylonitrile and 11.92 g of tetramethylethylene are added when preparing the fourth suspension. The resulting binder material has a solids content of 12.63 wt.%, the copolymer has a weight-average molecular weight of approximately 550,000 g / mol, and the copolymer can be fiberized to a length of 14 cm.

[0186] Comparative Example 7: Preparation of Adhesive Materials The preparation method of the binder material is the same as that described in Example 1, except that 8.66 g of sodium hydroxide is added when preparing the first suspension, 18.95 g of acrylic acid is added when preparing the second suspension, 18.69 g of acrylamide is added when preparing the third suspension, and 25.76 g of acrylonitrile is added when preparing the fourth suspension. The resulting binder material has a solid content of 10.23 wt.%, the copolymer has a weight-average molecular weight of approximately 550,000 g / mol, and the copolymer can be fiberized to 15 cm.

[0187] Comparative Example 8: Preparation of Adhesive Materials The preparation method of the binder material is the same as that described in Example 1, except that the polymerization process is controlled so that the weight-average molecular weight of the copolymer is approximately 320,000 g / mol. This copolymer can be fiberized to a length of 6 cm.

[0188] Comparative Example 9: Preparation of Adhesive Materials The binder material was prepared using the same method as described in Example 1, except that the polymerization process was controlled so that the copolymer had a weight-average molecular weight of approximately 750,000 g / mol. This copolymer was capable of being fiberized to a length of 13 cm.

[0189] Button battery assemblies of Examples 2-3, 6-9, 13-14 and Comparative Example 2-9 The button batteries in each embodiment and comparative embodiment are assembled in the same way as in embodiment 1, except that a corresponding binder material is used in the manufacture of the cathode.

[0190] Button battery assembly in Example 4 The button cell was assembled in the same manner as in Example 1, except that 0.25 kg of deionized water was added to the cathode electrode material mixture during preparation. The liquid content of the cathode electrode material mixture was approximately 7.7 wt.%.

[0191] Button battery assembly in Example 5 The button cell was assembled in the same manner as in Example 1, except that 0.80 kg of deionized water was added to the cathode electrode material mixture during preparation. The liquid content of the cathode electrode material mixture was approximately 21.1 wt.%.

[0192] Button battery assembly in Example 10 The button cell assembly method is the same as in Example 1, except that all NMC532 cells are replaced with NMC333 cells of the same quality (purchased from Shandong Tianjiao New Energy Co., Ltd., China).

[0193] Button battery assembly in Example 11 The button cell assembly method is the same as in Example 1, except that all NMC532 cells are replaced with NMC811 cells of the same quality (purchased from Shandong Tianjiao New Energy Co., Ltd., China).

[0194] Button battery assembly in Example 12 The button cell assembly method is the same as in Example 5, except that all NMC532 cells are replaced with LFP cells of the same mass (Tianjin Sterland Energy Technology Co., Ltd., China).

[0195] Comparative Example 1 Button Battery Assembly The button cell was assembled in the same way as in Example 1, except that N-methyl-2-pyrrolidone was used instead of water in the cathode manufacturing process.

[0196] Comparative Example 10 Button Battery Assembly The cathode electrode material mixture was prepared using the same method as in Example 1, except that only 0.10 kg of deionized water was added. The liquid content of this cathode electrode material mixture was approximately 3.2 wt.%. A suitable cathode could not be formed using this cathode electrode material mixture, therefore button cell assembly was not continued.

[0197] Button battery assembly in Comparative Example 11 The button cell was assembled in the same manner as in Example 1, except that 1.00 kg of deionized water was added to the cathode electrode material mixture during preparation. The liquid content of the cathode electrode material mixture was approximately 25.0 wt.%.

[0198] Button battery assembly in Comparative Example 12 The preparation method of the cathode material mixture is the same as in Example 1, except that a top-mounted stirrer is used first. The device operates at 1,200 rpm at 25°C. Should The copolymer is homogenized with deionized water for approximately 30 minutes to form a binder assembly. The adhesive composition is then added together with the positive electrode active material and conductive agent to the grounding electrode. of Planetary Hybrid instrument The mixture is stirred at approximately 200 rpm for about 30 minutes to form the electrode material mixture. Using this positive electrode material mixture, it is impossible to... A usable positive electrode was formed, so no further assembly of the coin cell was carried out.

[0199] Electrochemical measurements in Examples 2-11 and 13-14 The analysis method for button batteries in each embodiment is the same as that in Embodiment 1, and the results are shown in Table 1.

[0200] Electrochemical Measurements in Example 12 The analysis method for the button cell in Example 12 is the same as that in Example 1, except that the voltage range is 2.00 to 3.65 V, and the results are shown in Table 1.

[0201] Electrochemical measurements of Comparative Examples 1-12 The button batteries of each comparative example were analyzed as much as possible in the manner described in Example 1, and the results are shown in Table 2.

Claims

1. A method for manufacturing an electrode material mixture for a secondary battery, comprising the following steps: 1) The electrode active material and the dry binder material are homogenized to form a premix; as well as 2) Add water to the premix, and then homogenize the premix with water to form the electrode material mixture; The drying binder material is a copolymer.

2. The method according to claim 1, wherein the copolymer comprises hydrophilic and non-hydrophilic structural units, and wherein the copolymer, when dispersed in water, can be fiberized under shear force.

3. The method according to claim 2, wherein the hydrophilic structural unit comprises a monomeric unit derived from a monomer containing a hydrophilic functional group, wherein the monomer containing the hydrophilic functional group is selected from monomers containing an acid group, monomers containing an amide group, and combinations thereof; wherein the acid is selected from carboxylic acids, sulfonic acids, sulfuric acids, phosphonic acids, phosphoric acids, nitric acids, their salts, their derivatives, and combinations thereof.

4. The method according to claim 2, wherein the non-hydrophilic structural unit comprises a monomeric unit derived from monomers selected from nitrile-containing monomers, olefins, and combinations thereof.

5. The method of claim 2, wherein the proportion of hydrophilic structural units in the copolymer is about 60% to about 90% on a molar basis, based on the total molar number of monomer units in the copolymer.

6. The method of claim 3, wherein the total molar number of monomer units in the copolymer is approximately 10% to approximately 40% of the monomer units derived from the acid-containing monomers in the copolymer.

7. The method of claim 3, wherein the total molar number of monomer units in the copolymer is from about 10% to about 55% of the monomer units derived from amide-containing monomers in the copolymer.

8. The method of claim 4, wherein the total molar number of monomer units in the copolymer is from about 10% to about 40% by molar.

9. The method according to claim 3, wherein the carboxylic acid is selected from acrylic acid, methacrylic acid, crotonic acid, 2-butylcrotonic acid, cinnamic acid, maleic acid, fumaric acid, itaconic acid, 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, 3-Isopropylacrylic acid, trans-3-methyl-3-ethylacrylic acid, cis-3-methyl-3-ethylacrylic acid, 2-isopropylacrylic acid, trimethacrylic 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 Acrylic 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, methylmaleic acid, dimethylmaleic acid, phenylmaleic acid, bromomaleic acid, chloromaleic acid, dichloromaleic acid, fluoromaleic acid, difluoromaleic acid, nonyl maleate, decyl maleate, dodecyl maleate, octadecyl maleate, fluoroalkyl maleate, and combinations thereof.

10. The method according to claim 3, wherein the amide-containing monomer 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 Amines, N-(ethoxymethyl)methacrylamide, N-(propoxymethyl)methacrylamide, N-(butoxymethyl)methacrylamide, N,N-(dimethylaminopropyl)methacrylamide, N,N-(dimethylaminoethyl)methacrylamide, N,N-(dihydroxymethyl)methacrylamide, diacetone methacrylamide, diacetone acrylamide, methacryloylmorpholine, N-hydroxymethylacrylamide, N-methoxymethylacrylamide, N,N'-methylenebisacrylamide, N-hydroxymethylacrylamide, and combinations thereof.

11. The method according to claim 4, wherein the nitrile-containing monomer is selected from acrylonitrile, α-haloacrylonitrile, α-alkylacrylonitrile, α-chloroacrylonitrile, α-bromoacrylonitrile, α-fluoroacrylonitrile, methacrylonitrile, α-ethylacrylonitrile, α-isopropylacrylonitrile, α-n-hexylacrylonitrile, α-methoxyacrylonitrile, 3-methoxyacrylonitrile, 3-ethoxyacrylonitrile, α-acetoxyacrylonitrile, α-phenylacrylonitrile, α-tolylacrylonitrile, α-(methoxyphenyl)acrylonitrile, α-(chlorophenyl)acrylonitrile, α-(cyanophenyl)acrylonitrile, vinylidene cyanide, and combinations thereof.

12. The method of claim 1, wherein the weight-average molecular weight of the copolymer is from about 400,000 g / mol to about 700,000 g / mol.

13. The method of claim 2, wherein the fiberization of the copolymer occurs in the range of about 20 cm to about 40 cm.

14. The method of claim 1, wherein step 1) further comprises homogenizing the conductive agent with the electrode active material and the dry binder material to form a premix.

15. The method of claim 14, wherein the proportion of the copolymer in the electrode material mixture is from about 2% to about 10% by weight, based on the total weight of the electrode material mixture.

16. The method of claim 1, wherein the proportion of electrode active material in the electrode material mixture is from about 80% to about 99% by weight, based on the total weight of the electrode material mixture.

17. The method of claim 14, wherein, Based on the total weight of the electrode material mixture, the proportion of conductive agent in the electrode material mixture is approximately 1% to approximately 10% by weight.

18. The method according to claim 1, wherein, Based on the total weight of the electrode material mixture, the liquid content of the electrode material mixture is from about 5% to about 22% by weight.

19. The method of claim 1, wherein the time for preparing the premix in step 1) is from about 1 minute to about 60 minutes, and the time for homogenizing the water and the premix in step 2) is from about 1 minute to about 6 hours.

20. The method according to claim 1, wherein the temperature for preparing the premix in step 1) is from about 5°C to about 50°C, and the temperature for homogenizing the water and the premix in step 2) is from about 20°C to about 50°C.

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