Cathode and cathode slurry for secondary batteries

Abstract

The invention provides an aqueous-solvent-based cathode slurry for secondary batteries, comprising a cathode active material, a water-compatible copolymer binder, a lithium compound, and an aqueous solvent. The lithium compound in the cathode slurry serves as a lithium ion source to compensate for irreversible capacity loss due to SEI formation during initial charging of the battery. Battery cells prepared using the cathode slurry disclosed herein exhibit significantly improved electrochemical performance. The cathode for secondary batteries provided herein also includes a current collector and an electrode layer covering one or both sides of the current collector, the electrode layer comprising a cathode active material, a water-compatible copolymer binder, and a lithium compound, and the cathode is fabricated using the disclosed aqueous-solvent-based cathode slurry.

Description

[Technical Field]

[0001] The present invention relates to the field of batteries. In particular, the present invention relates to cathodes and cathode slurries for lithium-ion and other metal-ion batteries. [Background technology]

[0002] Over the past few decades, lithium-ion batteries (LIBs) have been widely used in a variety of applications, especially in consumer electronics, due to their excellent energy density, long life cycle, and high discharge capacity. Due to the rapid market growth of energy storage in electric vehicles (EVs) and power grids, high-performance and low-cost LIBs currently offer one of the most promising options for large-scale energy storage devices.

[0003] Lithium-ion batteries are usually fabricated in a discharged state. During the first charge, a passivated solid electrolyte interphase (SEI) is formed at the interface between the electrolyte and the anode. The SEI is formed from decomposition products of the electrolyte, which involves the consumption of lithium ions generated from the cathode. This phenomenon causes an irreversible loss of the battery's capacity because the lithium ions withdrawn from the cathode for SEI formation become unavailable, or remain as dead weight during subsequent battery processes. In fact, for anode active materials such as carbon, an initial capacity between 5% and 20% is lost in irreversible SEI formation. For anode active materials that expose a high surface area to contact with the electrolyte and undergo large volume changes during battery processing, more lithium ions are consumed in SEI formation. This is the case for silicon, where 20% to 40% of the initial capacity is consumed for SEI formation. However, an SEI that is permeable to lithium ions is extremely important for the battery because the presence of the SEI prevents further undesirable decomposition of the electrolyte. In view of such problems, attempts have been made to mitigate or compensate for this loss of lithium ions in order to increase or maximize the reversible capacity of lithium-ion batteries.

[0004] The replenishment of metal ions on the anode has been widely investigated to reduce the irreversible capacity loss during the initial charge. However, the contact between metallic lithium and the anode is accompanied by a potential of 0 V vs Li / Li + for Li generation. This is similar to causing several side reactions and can destroy existing anode active materials. Furthermore, lithium, which is a highly chemically active metal, cannot remain stable in air without reacting, so such batteries require a stringent environment for manufacturing, which is very difficult to meet on an industrial scale and inevitably raises serious safety concerns.

[0005] For the case of 0 < x <= 1, the compound Li 1+x ​​The use of Mn2O4 as the cathode active material is thought to offer a solution to offset this lithium loss due to its ability to intercalate a second lithium ion per formula unit to form Li2Mn2O4 via chemical treatment with a mild reducing agent such as LiI (Tarascon, JM and Guyomard, D. (1991) "Li Metal-Free Rechargeable Batteries Based on Li 1+x Mn2O4Cathodes (0<=x<=1) and Carbon Anodes”, J. Electrochem. Soc., Vol. 138, No. 10, pp. 2864-2868).Li2Mn2O4, Li 1+x Mn2O4(0 <x<=1)、またはLi 1+x Due to the use of a mixture of Mn2O4 as the cathode active material, excess Li+ can be used during initial charging to overcome irreversible capacity loss compared to conventional cathode active materials such as LiMn2O4 (where x is 0). However, this technique requires the use of Li x It is specific to Mn2O4 compounds and is produced by chemical lithiation of Li x Mn2O4 Li 1+x The phase change to Mn2O4 results in mechanical stress on the metal oxide, shortening the battery's lifespan.

[0006] Chinese Patent Application Publication No. 102148401A introduces a method for pre-forming an SEI on the anode surface prior to battery assembly to reduce irreversible capacity loss. The disadvantage of this method is that after pre-forming the SEI, conditions such as temperature and humidity must be strictly controlled in the subsequent preparation process to prevent oxidation of the SEI, which is extremely difficult to implement over a long period of time.

[0007] Chinese Patent Application Publication No. 109742319A discloses a battery electrode that can consist of either a cathode sheet or an anode sheet. The cathode sheet is composed of an outer layer of lithium-rich oxide coated on top of a cathode slurry film. The anode sheet is composed of a binder layer consisting of lithium powder and CMC (carboxymethyl cellulose). These derivatives are located between the anode slurry film and the current collector. In this electrode configuration, (1) the binder layer covering the current collector of the anode sheet exhibits a corrosion-resistant function that can reduce the tendency for SEI formation on the anode sheet surface and reduce the uptake of lithium ions from the cathode sheet. (2) Only the outer lithium-rich oxide layer of the cathode sheet is consumed for SEI formation during initial charging, without the utilization of lithium ions from the cathode film. However, reducing SEI formation can lead to the problem of not being able to further suppress the decomposition of the remaining electrolyte. Furthermore, the incorporation of a lithium-rich oxide layer in the cathode sheet and a binder layer in the anode sheet naturally reduces the overall amount of cathode and anode active material in the electrodes. Therefore, the effectiveness of such electrode configurations for improving the energy density and cycle life of batteries is highly questionable. Furthermore, the method does not provide sufficient data to support its findings and evaluate the electrochemical performance of the electrodes.

[0008] Typically, lithium-ion battery electrodes are fabricated by casting a slurry onto a metal current collector. Such slurries may contain electrode active materials, conductive carbon, and a binder in a solvent. The binder provides good electrochemical stability, holds the electrode active materials together, and adheres them to the current collector in the electrode being fabricated. PVDF (Polyvinylidene fluoride) is one of the most commonly used binders in the commercial lithium-ion battery industry. PVDF is soluble only in certain organic solvents, such as N-methyl-2-pyrrolidone (NMP). Therefore, organic solvents such as NMP are commonly used as solvents to prepare electrode slurries when the binder is PVDF.

[0009] Chinese Patent Application Publication No. 104037418 discloses a cathode film for a lithium-ion battery prepared via a slurry method, which contains a lithium-containing transition metal oxide cathode active material, a conductive agent, a binder, and a lithium ion replenishment agent for compensating for irreversible capacity loss. In this patent application, an organic solvent such as NMP is preferred as the solvent for the slurry. However, NMP is flammable and toxic, requiring special handling. Furthermore, an NMP recovery system must be properly implemented during the drying process to recover vaporized NMP. This requires significant research funding and thus incurs significant costs in the manufacturing process. Therefore, production of the cathode film in this patent application is limited by the requirement to use NMP, an expensive and toxic organic solvent.

[0010] The use of lower cost, more environmentally friendly solvents, such as aqueous solvents, most commonly water, is preferred in the present invention because water is significantly safer than NMP and does not require the implementation of a recovery system. The use of aqueous solvents instead of organic solvents in the production of electrode slurries reduces production costs and environmental impact, and therefore, aqueous-based cathode slurries are contemplated in the present invention.

[0011] The problem of significant irreversible lithium ion loss from SEI formation during initial charging is not alleviated by using an aqueous solvent instead of an organic solvent to produce cathode films via a slurry. Conversely, producing a cathode using an aqueous solvent-based cathode slurry presents the additional challenge of lithium dissolution from the active material into the aqueous solvent of the slurry. For this reason, the reversible capacity involved in subsequent cycles in batteries incorporating cathodes produced via an aqueous solvent-based slurry is significantly lower than that of batteries including cathodes produced via conventional organic solvent-based slurries. Thus, to reduce irreversible capacity loss in lithium-ion batteries and other metal-ion batteries, a solution is needed to develop a means to compensate for metal ion loss, particularly in cathodes produced via an aqueous solvent-based cathode slurry.

[0012] In view of the above, the present inventors have intensively researched this subject and discovered that the problem of irreversible capacity loss due to SEI formation can be solved by the addition of lithium compounds to aqueous solvent-based cathode slurries, whereby the lithium compounds dissolved in the aqueous solvent-based cathode slurries, which are cathodes for lithium ion batteries, decompose within the operating potential window of the cathode active material. Such lithium compounds are excellent at compensating for irreversible capacity loss in lithium ion batteries, and furthermore, do not increase the resistance of the cathode, thereby resulting in superior battery electrochemical performance.

[0013] The ability of the lithium compounds to be dissolved in the aqueous solvent-based cathode slurry is important because it ensures that the lithium compounds are well dispersed within the aqueous solvent-based cathode slurry and ensures a more uniform distribution of the lithium compounds within the cathode layer when coated, by preventing local inconsistencies and non-uniformities due to unequal lithium ion loss in these regions caused by uneven distribution of the lithium compounds in the cathode layer. These local inconsistencies and non-uniformities can lead to poor electrochemical performance of the battery.

[0014] The ability of the lithium compound to decompose in the operating potential window of the cathode active material is also important. In the cathode, strong ionic interactions between lithium cations and anions in the lithium compound cause poor mobility of lithium cations from the lithium compound when anions are present. When the cathode is used in a battery and the battery is cycled, the anions decompose, which frees up lithium cations from the lithium compound to replenish the battery's lithium ion capacity.

[0015] Both properties, combined with the ability to dissolve and be dissolved within the operating potential window of the cathode active material, and the presence of the lithium compound, serve to ensure small, uniform pore sizes and a uniform pore distribution within the cathode after the cathode undergoes an initial charge. Small, uniform pore sizes have the added benefit of providing reduced diffusion paths for rapid lithium ion transport into the cathode, ensuring full utilization of the cathode active material. Similarly, pore uniformity ensures the absence of localized inconsistencies and non-uniformities, allowing for efficient electrolyte distribution and reducing areas of the cathode where lithium ions cannot reach, resulting in full cathode utilization and superior electrochemical performance in the battery.

[0016] The selection of the binder is also critical to the battery's performance. Common binders, such as PVDF, are insoluble in aqueous-based cathode slurries. Surfactants are added to disperse these binders, but the presence of surfactants in the cathode layer can degrade the battery's electrochemical performance. Therefore, a further aim of the invention is to disclose water-compatible copolymers suitable for use as binders in the aqueous-based cathode slurries disclosed herein. Such binders have good dispersion in the aqueous-based cathode slurry. This ensures good binding ability of the binder with other cathode layer materials, as well as the cathode layer on the current collector when the aqueous-based cathode slurry is coated on the current collector, contributing to a battery with excellent electrochemical performance. Summary of the Invention

[0017] The aforementioned needs are met by various aspects and embodiments disclosed herein. In one aspect, provided herein is an aqueous solvent-based cathode slurry for a secondary battery, comprising a cathode active material, a copolymer binder, and a lithium compound in an aqueous solvent. In some embodiments, the copolymer binder is water-compatible. In another aspect, provided herein is a cathode for a secondary battery, fabricated by coating a current collector with the aforementioned aqueous solvent-based cathode slurry.

[0018] In some embodiments, the lithium compound may be soluble in the aqueous solvent-based cathode slurry, ie, decomposes within the operating potential window of the cathode active material.

[0019] The lithium compounds serve as a source of lithium ions to compensate for irreversible capacity loss in lithium-ion batteries. The solubility of the lithium compounds in aqueous-solvent-based cathode slurries allows the compounds to be uniformly distributed in the coated cathode layer. The decomposition of the lithium compounds ensures the mobility of lithium ions from the lithium compounds. As a result, lithium-ion battery cells containing cathodes prepared using aqueous-solvent-based cathode slurries containing the lithium compounds disclosed herein exhibit excellent electrochemical performance. Similarly, other metal-ion batteries may use other metal compounds compatible with the corresponding battery chemistry to provide equivalent effectiveness in compensating for irreversible capacity loss. [Brief explanation of the drawings]

[0020] [Figure 1] FIG. 1 is a flow chart of an embodiment illustrating a procedure for cathode preparation via the cathode slurry disclosed herein.

[0021] [Figure 2a] FIG. 2a shows an SEM image of the distribution of lithium squarate with the cathode active material NMC811 prepared via an aqueous solvent-based slurry at 10,000x magnification. [Figure 2b] FIG. 2b shows an SEM image of the distribution of lithium squarate with the cathode active material NMC811 prepared using a solvent-free dry method at 10,000× magnification. [Figure 2c] FIG. 2c shows an SEM image of the distribution of lithium squarate with the cathode active material NMC811 prepared using a solvent-free dry method at 400x magnification.

[0022] [Figure 3a]FIG. 3a shows an SEM image of the surface of a cathode produced via an aqueous solvent-based slurry, comprising lithium oxalate as the lithium compound, lithium nickel manganese oxide (LNMO), and cathode active material, before the first charge / discharge cycle at 10.00x magnification. [Figure 3b] FIG. 3b shows an SEM image of the cathode surface, produced via an aqueous solvent-based slurry, containing lithium oxalate as the lithium compound, lithium nickel manganese oxide (LNMO), and cathode active material, after the first charge / discharge cycle at 10,000x magnification. [Figure 3c] FIG. 3c shows an SEM image of the cathode surface, at 10.00x magnification, of a cathode produced via an organic solvent-based slurry, where the organic solvent is more specifically NMP, comprising lithium oxalate as the lithium compound, lithium nickel manganese oxide (LNMO), and the cathode active material, before the first charge / discharge cycle. [Figure 3d] FIG. 3d shows an SEM image of the cathode surface, containing lithium oxalate as the lithium compound, lithium nickel manganese oxide (LNMO), and cathode active material, produced via an organic solvent-based slurry, where the organic solvent is more specifically NMP, after the first charge / discharge cycle at 10.00x magnification. DETAILED DESCRIPTION OF THE INVENTION

[0023] In one aspect, provided herein is an aqueous solvent-based cathode slurry for a secondary battery, comprising a cathode active material, a copolymer binder, a lithium compound, and an aqueous solvent. In another aspect, provided herein is a cathode for a secondary battery, the cathode being prepared by coating a current collector with the aforementioned aqueous solvent-based cathode slurry.

[0024] The term "electrode" refers to either a "cathode" or an "anode."

[0025] The term "positive electrode" is used interchangeably with "cathode." Similarly, the term "negative electrode" is used interchangeably with "anode."

[0026] The terms "binder" and "binder substance" refer to a chemical compound, mixture of compounds, or polymer used to hold electrode materials and / or conductive agents with and attached to conductive metal portions to form an electrode. In some embodiments, the electrode does not include a conductive agent. In some embodiments, the binder substance forms a solution or colloid in an aqueous solvent, such as water.

[0027] The term "conductive agent" refers to a material that has good electrical conductivity. Therefore, conductive agents are often mixed with electrode active materials when forming electrodes to improve the electrical conductivity of the electrodes. In some embodiments, the conductive agent is chemically active. In some embodiments, the conductive agent is chemically inactive.

[0028] The term "polymer" refers to a compound prepared by polymerization of monomers, whether of the same or different types. The general term "polymer" encompasses "homopolymers" as well as "copolymers."

[0029] The term "homopolymer" refers to a polymer prepared by the polymerization of monomers of the same type.

[0030] The term "copolymer" refers to a polymer prepared by the polymerization of two or more different types of monomers.

[0031] The term "polymeric binder" refers to a binder of polymeric nature. The term "copolymeric binder" refers to a polymeric binder, in particular where the binder is a copolymer.

[0032] The term "water-compatible" refers to a chemical compound, mixture of compounds, or polymer that can be well dispersed in water to form a solution or colloid. In some embodiments, the colloid is a suspension.

[0033] The term "aqueous solvent" refers to a solvent that is water or that includes water and one or more minor components, with water comprising the majority of the solvent system by weight. In some embodiments, the ratio of water to the total minor components in the solvent system is 51:49, 53:47, 55:45, 57:43, 59:41, 61:39, 63:37, 65:35, 67:33, 69:31, 71:29, 73:27, 75:25, 77:23, 79:21, 81:19, 83:17, 85:15, 87:13, 89:11, 91:9, 93:7, 95:5, 97:3, 99:1, or 100:0 by weight, based on the total weight of the solvent system.

[0034] The term "solubility ratio" with respect to a lithium compound refers to the ratio of the molar solubility of the lithium compound in an aqueous solvent-based cathode slurry at room temperature to the moles of the lithium compound per unit volume in the aqueous solvent-based cathode slurry. In some embodiments, when both the molar solubility (e.g., mol / L) and the moles per unit volume (e.g., mol / L) have the same units, the solubility ratio is dimensionless. In some embodiments, when the solubility ratio is dimensionless, the solubility ratio is greater than or equal to 1 because the lithium compound present in the aqueous solvent-based cathode slurry is insoluble. This is advantageous for achieving good dispersion of the lithium compound in the aqueous solvent-based cathode slurry.

[0035] As used herein, the term "unsaturated" refers to a moiety having one or more units of unsaturation.

[0036] The terms "alkyl" or "alkyl group" refer to a monovalent group derived from a saturated unbranched or branched aliphatic hydrocarbon by the removal of a hydrogen atom and having the general formula CH, where n is an integer, or an integer between 1 and 20, or between 1 and 8. Examples of alkyl groups include, but are not limited to, (C1-C8) alkyl groups such as methyl, ethyl, propyl, isopropyl, 2-methyl-1-propyl, 2-methyl-2-propyl, 2-methyl-1-butyl, 3-methyl-1-butyl, 2-methyl-3-butyl, 2,2-dimethyl-1-propyl, 2-methyl-1-pentyl, 3-methyl-1-pentyl, 4-methyl-1-pentyl, 2-methyl-2-pentyl, 3-methyl-2-pentyl, 4-methyl-2-pentyl, 2,2-dimethyl-1-butyl, 3,3-dimethyl-1-butyl, 2-ethyl-1-butyl, butyl, isobutyl, t-butyl, pentyl, isopentyl, neopentyl, hexyl, heptyl, and octyl. Longer alkyl groups include nonyl and decyl groups. An alkyl group can be unsubstituted or substituted with one or more suitable substituents. Furthermore, an alkyl group can be branched or unbranched. In some embodiments, it contains at least 2, 3, 4, 5, 6, 7, or 8 carbon atoms.

[0037] The term "cycloalkyl" or "cycloalkyl group" refers to a saturated or unsaturated cyclic non-aromatic hydrocarbon group having a single ring or multiple condensed rings. Examples of cycloalkyl groups include, but are not limited to, (C3-C7) cycloalkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, and cycloheptyl, saturated cyclic and bicyclic terpenes, (C3-C7) cycloalkenyl groups such as cyclopropenyl, cyclobutenyl, cyclopentenyl, cyclohexenyl, and cycloheptenyl, and unsaturated cyclic and bicyclic terpenes. A cycloalkyl group may be unsubstituted or substituted with one or two suitable substituents. Furthermore, a cycloalkyl group can be monocyclic or polycyclic. In some embodiments, a cycloalkyl group contains at least 5, 6, 7, 8, 9, or 10 carbon atoms.

[0038] The term "alkoxyl" refers to an alkoxyl group, as previously defined, attached to the main carbon chain through an oxygen atom. Some non-limiting examples of alkoxyl groups include methoxy, ethoxyl, propoxy, butoxy, and the like. Alkoxyl, as defined above, can be substituted or unsubstituted, where the substituent is, but is not limited to, deuterium, hydroxy, amino, halogen, cyano, alkoxyl, alkyl, alkenyl, alkynyl, mercaptan, nitro, and the like.

[0039] The term "alkenyl" refers to an unsaturated straight-chain, branched-chain, or cyclic hydrocarbon group containing one or more carbon-carbon double bonds. Examples of alkenyl groups include, but are not limited to, ethenyl, 1-propenyl, and 2-propenyl, and one or more carbon atoms in the group can be optionally substituted.

[0040] The term "aryl" or "aryl group" refers to an organic radical formed by removing a hydrogen atom from a monocyclic or polycyclic aromatic hydrocarbon. Non-limiting examples of aryl groups include phenyl, naphthyl, benzyl, and tolanyl groups, sexiphenylene, phenanthrenyl, anthracenyl, coronenyl, and tolanylphenyl. An aryl group can be unsubstituted or substituted with one or more suitable substituents. Furthermore, an aryl group can be monocyclic or polycyclic. In some embodiments, an aryl group contains at least 6, 7, 8, 9, or 10 carbon atoms.

[0041] The term "aliphatic" refers to C1 to C 30 Alkyl groups from C2 to C 30 Alkenyl groups, C2 to C 30 Alkynyl groups, C1 to C 30 Alkylene groups, C2 to C 30 Alkenylene groups of C2 to C 30 In some embodiments, the alkyl group contains at least 2, 3, 4, 5, 6, 7, or 8 carbon atoms.

[0042] The term "aromatic" refers to a group consisting of an aromatic hydrocarbon ring, optionally containing heteroatoms or substituents. Examples of such groups include, but are not limited to, phenyl, tolyl, biphenyl, o-terphenyl, m-terphenyl, p-terphenyl, naphthyl, anityl, phenanthryl, pyrenyl, triphenylenyl, and derivatives thereof.

[0043] The term "substituent" as used to describe compounds and chemical moieties refers to at least one hydrogen atom of a compound or chemical moiety that is replaced with a second chemical moiety. Examples of substituents include, but are not limited to, halogen, alkyl, heteroalkyl, alkenyl, alkynyl, aryl, heteroaryl, hydroxyl, alkoxyl, amino, nitro, thiol, thioether, imine, cyano, amido, phosphonate, phosphine, carboxyl, thiocarbonyl, sulfonyl, sulfonamido, acyl, formyl, acyloxy, alkoxycarbonyl, oxo, haloalkyl (e.g., trifluoromethyl), monocyclic or fused or non-fused polycyclic carbocyclic cycloalkyl (e.g., cyclopropyl, cyclobutyl, cyclopentyl, or cyclohexyl), or monocyclic or fused or non-fused polycyclic heterocycloalkyl (e.g., pyrrolidinyl, piperidinyl, piperazinyl, morpholinyl, or thiazinyl), carbocyclic or heterocyclic, monocyclic or fused or non-fused polycyclic aryl (e.g., phenyl, naphthyl, pyrrolidin ... aryl, indolyl, furaryl, thiophenyl, imidazolyl, oxazolyl, isozazolyl, thiazolyl, triazolyl, tetrazolyl, pyrazolyl, pyridinyl, quinolinyl, isoquinolinyl, acridinyl, pyrazinyl, pyridazinyl, pyrimidinyl, benzimidazolyl, benzothiophenyl, or benzofuranyl), amino (primary, secondary, or tertiary), o-lower alkyl, o-aryl, aryl-lower alkyl, -CO2CH3, -O Examples of suitable substituents include CH2CONH2, -NH2, -SON2NH2, -OCHF2, -CF3, -OCF3, -NH(alkyl), -N(alkyl), -NH(aryl), -N(alkyl)(aryl), -N(aryl), -CHO, -CO(alkyl), -CO(aryl), -CO2(alkyl), and -CO2(aryl), and moieties optionally substituted with bridged or fused cyclic structures, such as, for example, -OCHO-. These substituents may be further optionally substituted with groups selected from such groups. All chemical groups disclosed herein may be substituted unless specified.

[0044] The term "halogen" or "halo" refers to F, Cl, Br, or I.

[0045] The term "structural units" refers to the total amount of monomer units contributed by the same monomer type in a polymer.

[0046] The term "acid base" refers to an acid salt formed when an acid functional group reacts with a base. In some embodiments, a proton of the acid functional group is replaced with an ammonium ion. In some embodiments, the acid functional group is selected from the group consisting of carboxylic acids, sulfonic acids, and phosphonic acids.

[0047] The term "homogenizer" refers to equipment that can be used for homogenizing a substance. The term "homogenization" refers to the process of uniformly dispersing a substance in a fluid. Conventional homogenizers can be used for the methods disclosed herein. Some non-limiting examples of homogenizers include steering mixers, planetary steering mixers, blenders, and ultrasonic devices.

[0048] The term "planetary mixer" refers to equipment that can be used to mix or agitate different materials to produce a uniform mixture, consisting of blades that undergo planetary motion within a vessel. In some embodiments, a planetary mixer includes at least one planetary blade and at least one high-speed dispersing blade. The planetary and high-speed dispersing blades rotate on their respective axes and rotate continuously around the vessel. The rotational speed is expressed in revolutions per minute (rpm), which refers to the number of revolutions the rotor completes in one minute.

[0049] The term "ultrasonicator" refers to equipment capable of applying ultrasonic energy to agitate particles in a sample. Any ultrasonicator capable of dispersing the aqueous solvent-based cathode slurries disclosed herein can be used herein. Some non-limiting examples of ultrasonicators include ultrasonic baths, prototype ultrasonicators, and ultrasonic flow cells.

[0050] The term "ultrasonic bath" refers to a device that transmits ultrasonic energy to a liquid sample through the walls of the ultrasonic bath vessel.

[0051] The term "prototype ultrasonic device" refers to an ultrasonic probe immersed in a medium for direct sonication. The term "direct sonication" is a method in which ultrasound waves are coupled directly into the liquid to be treated.

[0052] The term "ultrasonic flow cell" or "ultrasonic reaction chamber" refers to a device capable of performing sonication in flow-through mode. In some embodiments, the ultrasonic flow cell is in a single-pass, multi-pass, or circulating configuration.

[0053] The term "apply" is the action of laying or spreading a substance on a surface.

[0054] The term "current collector" refers to a conductive substrate that contacts an electrode layer and can conduct current to the electrode during discharge or charging of a secondary battery. Some non-limiting examples of current collectors include a single conductive metal layer or substrate, and a single conductive metal layer or substrate over a conductive coating layer, such as a graphite-based coating layer. The conductive metal layer and substrate have a three-dimensional network structure and can be in the form of a polymer or metal material, or a porous body that can be metal or polymer, or a foil. In some embodiments, the three-dimensional porous current collector is covered with a conformal carbon layer.

[0055] The term "electrode layer" refers to a layer in contact with a current collector that contains electrochemically active material. In some embodiments, the electrode layer is made by applying a coating to the current collector. In some embodiments, the electrode layer is located on the surface of the current collector. In other embodiments, a three-dimensional porous current collector is conformally coated with the electrode layer.

[0056] The term "doctor blading" refers to a process for creating large area films on rigid or flexible substrates. Coating thickness can be controlled by an adjustable gap between the coating blade and the coating layer, allowing for the deposition of variable wet layer thicknesses.

[0057] The term "slot die coating" refers to a process for producing large area films of rigid or flexible substrates. The slurry is applied to the substrate by continuously pumping it through a nozzle onto the substrate, attached to a roller and constantly feeding the nozzle. The thickness of the coating is controlled by various methods, such as varying the flow rate of the slurry or the speed of the roller.

[0058] The term "room temperature" refers to an indoor temperature of about 18°C ​​to about 30°C, e.g., 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, or 30°C. In some embodiments, room temperature refers to a temperature of about 20°C to + / - 1°C, or + / - 2°C, or + / - 3°C. In other embodiments, room temperature refers to a room temperature of about 22 degrees or about 25 degrees.

[0059] The term "particle size D5" refers to the volume-based cumulative 50% size (D50), which is the particle size at the 50% point on the cumulative curve (i.e., the particle diameter at the 50th percentile (median) of the particle volume) when the total volume is 100% and a cumulative curve is drawn to obtain the particle size distribution on a volume basis. Furthermore, in the cathode active material of the present invention, particle size D50 refers to the volume-average particle size of secondary particles formed by the mutual aggregation of primary particles, or, when the particles are composed only of primary particles, refers to the volume-average particle size of the primary particles.

[0060] The term "particle size D10" refers to the volume-based cumulative 10% size (D10), which is the particle size at the 10% point on the cumulative curve (i.e., the diameter of the particle at the 10th percentile of the particle's volume) when the total volume is 100% and the cumulative curve is drawn to obtain the particle size distribution on a volume basis.

[0061] The term "particle size D90" refers to the volume-based cumulative 90% size (D90), which is the particle size at the 90% point on the cumulative curve (i.e., the diameter of the particle at the 90th percentile of the particle's volume) when the total volume is 100% and the cumulative curve is drawn to obtain the particle size distribution on a volume basis.

[0062] The term "solids" refers to the amount of non-volatile material remaining after evaporation.

[0063] The term "peel strength" refers to the amount of force required to separate two materials that are adhered to one another, such as a current collector and an electrode active material coating. It is a measure of the adhesive strength between such two materials and is usually expressed in N / cm.

[0064] The term "C-rate" refers to the charge or discharge rate of a cell or battery, expressed in Ah or mAh, at its total stored capacity. For example, a rate of 1C means it takes 1 hour to utilize all of the stored energy, 0.1C means it takes 1 hour to utilize 10% of the energy, or 10 hours for full energy, and 5C means it takes 12 minutes to utilize full energy.

[0065] The term "ampere-hour (Ah)" refers to the unit used to specify the storage capacity of a battery. For example, a battery with a 1 Ah capacity can supply 1 ampere of current for 1 hour, or 0.5 amperes of current for 2 hours, etc. Therefore, 1 ampere-hour (Ah) is equivalent to 3,600 coulombs of charge. Similarly, the term "milliampere-hour (mAh)" also refers to the unit of storage capacity of a battery and is 1 / 1,000 of an ampere-hour.

[0066] The term "battery cycle life" refers to the number of complete charge / discharge cycles a battery can undergo before the battery's nominal capacity falls below 80% of its initial rated capacity.

[0067] The term "capacity" is a characteristic of an electrochemical cell, such as a battery, that refers to the total amount of charge that the cell can hold. Capacity is typically expressed in units of ampere-hours. The term "specific capacity" refers to the power output capacity per unit mass of an electrochemical cell, such as a battery, and is usually expressed in Ah / kg or mAh / g.

[0068] In the following, all numbers disclosed herein, whether associated with the word "about" or "approximately," are approximate values. They may vary by 1 percent, 2 percent, 5 percent, or sometimes 10 to 20 percent. The lower limit R L and upper bound R U Whenever a numerical range is disclosed, any number falling within that range is specifically disclosed. In particular, any subsequent number within the range is specifically disclosed. L +k*(R U -R L ), where k is a variable ranging from 0 percent to 100 percent. Furthermore, any numerical range is specifically disclosed by two R numbers defined above.

[0069] In this description, all references to the singular include references to the plural and vice versa. In this description, all references to "aqueous solvent" may specifically refer to water in the context of embodiments of this invention that exclusively use water as the aqueous solvent.

[0070] Currently, in lithium-ion batteries, intercalation / deintercalation in the anode is usually performed by Li / Li +This occurs at low potentials relative to the anode surface, where non-aqueous liquid electrolytes are thermodynamically unstable. During initial charging, electrolyte decomposition inevitably occurs in an irreversible manner, leading to the formation of a solid electrolyte interface (SEI) across the anode surface. This is beneficial in that the formed SEI can inhibit further decomposition of the electrolyte, providing satisfactory cyclability for lithium-ion batteries. However, SEI formation is undesirable with respect to the rated capacity of lithium-ion batteries because a portion of the cathode active material is irreversibly consumed to provide lithium ions for SEI formation in the anode. Therefore, various methods are disclosed for reducing the impact of irreversible capacity loss due to SEI formation.

[0071] Currently, cathodes are often prepared by dispersing the cathode active material, binder material, and conductive agent in an organic solvent such as N-methyl-2-pyrrolidone (NMP) to form a cathode slurry, then coating the cathode slurry on a current collector and allowing it to dry. However, these organic solvents can pose severe environmental hazards, can be toxic, and require complex and specialized handling.

[0072] Therefore, the use of aqueous solvents is preferred, and aqueous-solvent-based slurries are contemplated in the present invention. In addition to suffering from irreversible lithium ion loss due to the formation of an SEI, an additional obstacle for lithium-ion batteries including cathodes fabricated with aqueous-solvent-based cathode slurries is the tendency for lithium to leach from the cathode active material during the preparation of aqueous-solvent-based cathode slurries. As a result, cathodes prepared using aqueous-solvent-based slurries possess relatively lower reversible capacity, which can contribute to further battery operation, compared to cathodes prepared using conventional organic solvent-based slurries. Therefore, there is a need to establish a means of compensating for lithium ion loss in order to increase or maximize the reversible capacity of lithium-ion batteries, particularly for aqueous-solvent-based cathode slurries.

[0073] The primary objective of the present invention is to provide an aqueous solvent-based cathode slurry, which is a cathode for a lithium-ion battery, that reduces or eliminates irreversible lithium ion loss due to SEI formation. In response to the above problems, based on research into the present invention, it has been discovered that there exists a replenishing lithium compound in the aqueous solvent-based cathode slurry, so that the lithium battery cathode prepared with such an aqueous solvent-based cathode slurry can compensate for the irreversible lithium ion loss in the lithium-ion battery to achieve an increase in the rated capacity of the battery and significantly contribute to the electrochemical performance of the battery.

[0074] The lithium compounds applied in this invention have the following characteristics: (1) they are soluble in aqueous solvent-based cathode slurries, (2) they undergo decomposition during the first charge of the assembled battery within the operating potential window of the cathode active material (most commonly 3.0 V to 4.7 V), and (3) they have oxidizable anions that lose electrons upon first charge.

[0075] Generally, lithium compounds exhibit relatively low electrical conductivity. Therefore, it is expected that the introduction of non-conductive lithium compounds into the cathode will impose an increase in resistance (i.e., interfacial resistance, complex volume resistivity within the cathode). However, it is known that lithium compounds soluble in aqueous solvent-based cathode slurries can distribute the lithium compounds homogeneously within the aqueous solvent-based cathode slurry, resulting in negligible impact on interfacial resistance and intermixing of the lithium compounds into the aqueous solvent-based cathode slurry used to fabricate the cathode and complex volume resistivity within the cathode. This indicates that the electrical conductivity of the aqueous solvent-based cathode slurry remains optimal, thus promoting enhanced battery electrochemical performance.

[0076] Upon first charge, the lithium compound undergoes decomposition within the operating potential range of the cathode active material to produce lithium ions that can either be immediately consumed due to SEI formation or can be utilized in subsequent cycles of the battery. Therefore, the addition of lithium compounds to aqueous solvent-based cathode slurries, and cathodes fabricated using such aqueous solvent-based cathode slurries, compensates for the lithium ions lost during the first cycle of a battery containing the cathode due to SEI formation.

[0077] In some embodiments, decomposition of the anion of the lithium compound produces gaseous products, which, due to their inherent solubility in aqueous solvent-based cathode slurries, can be homogeneously distributed within the aqueous solvent-based cathode slurries of the present invention. Due to the release of such gaseous products, the pores formed in cathodes produced using such cathode slurries have small, consistent pore sizes with uniform pore distribution. These gaseous products can be evacuated prior to sealing the battery to avoid pressure buildup within the battery.

[0078] Pores in the cathode facilitate electrolyte penetration and help provide diffusion paths for Li+ transport through the electrolyte. A small average pore size within the cathode significantly increases the surface area of ​​the cathode and reduces the diffusion paths of lithium ions into the cathode, thereby allowing for more effective charge transport across the cathode-electrolyte interface. The resulting consistent pore size within the cathode provides suitable open volume for mass transport and allows for efficient electrolyte distribution. Uniform pore distribution in the cathode reduces the area of ​​the cathode where lithium ions cannot reach, resulting in underutilization of the cathode.

[0079] Therefore, a function of the present invention is to ensure that after undergoing the first charge, the cathode produced via the cathode slurry of the present invention will yield a structure with small and consistent pore size morphology with uniform pore distribution, which can ensure improved insertion and extraction of lithium ions with reduced diffusion paths, leading to enhanced electrochemical performance.

[0080] In contrast, the aforementioned improvement is not achievable with cathodes prepared using organic solvent-based slurries (e.g., slurries using NMP as the solvent). Because of the insolubility of lithium ions in non-aqueous solvents, lithium compounds tend to form clusters and are unevenly distributed within the cathode slurry. As a result, relatively larger and more variable pore sizes with uneven pore distribution within the cathode structure are formed upon first charge. Thus, pores may be concentrated in some areas and absent in others. The uneven pore distribution can result in reduced utilization of the cathode active material. This can cause overuse of certain areas, reducing the rated capacity of the cathode and limiting the full utilization of the cathode active material within the cathode. It has been discovered that cathodes containing lithium compounds prepared using organic solvent-based slurries exhibit resistance increases within the cathode that are at least four times greater than comparable cathodes prepared using organic solvent-based slurries without incorporated lithium compounds. No improvement in the electrochemical performance of batteries containing cathodes prepared with organic solvent-based slurries containing lithium compounds was observed.

[0081] Thus, the present invention provides a method for preparing a cathode slurry comprising a cathode active material, a copolymer binder, a lithium compound, and an aqueous solvent. Such a cathode slurry can then be coated onto a current collector to form a cathode. The addition of a lithium compound to the aqueous solvent-based cathode slurry and cathode of the present invention has the combined effect of maintaining a consistently low resistance within the cathode and providing a source of lithium ions to compensate for irreversible capacity loss. Furthermore, it has been discovered that negative electrodes fabricated using the disclosed cathode slurries have small, consistent pore sizes with uniform pore distribution after undergoing the first charge. As a result, the reversible capacity and cycling performance of lithium-ion batteries containing cathodes produced using the aqueous solvent-based cathode slurries of the present invention are significantly improved.

[0082] 1 is a flow chart of an embodiment showing steps of a method 100 of preparing a cathode using a cathode slurry disclosed herein. In some embodiments, the cathode slurry is an aqueous solvent-based cathode slurry. In some embodiments, the aqueous solvent-based cathode slurry is first formed by dispersing a lithium compound in an aqueous solvent in step 101 to form a first suspension.

[0083] In some embodiments, the aqueous solvent is water. In such embodiments, the aqueous solvent-based cathode slurry composition does not include an organic solvent, thereby avoiding the expensive and specialized handling of organic solvents during cathode slurry preparation. 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), DO, and combinations thereof.

[0084] In some embodiments, the aqueous solvent is a solution containing water as a major component and a volatile solvent as a minor component in addition to water. Examples of such volatile solvents include, but are not limited to, alcohols, lower aliphatic ketones, lower alkyl acetates, and the like. While such volatile solvents are organic solvents, a transition to using aqueous solvent-based slurries for producing battery cathodes is desirable to reduce volatile organic compound emissions and increase processing efficiency. In some embodiments, the percentage of water in the aqueous solvent is, by weight, about 51% to about 100%, about 51% to about 95%, about 51% to about 90%, about 51% to about 85%, about 51% to about 80%, about 51% to about 75%, about 51% to about 70%, about 55% to about 100%, about 55% to about 95%, about 55% to about 90%, about 55% to about 85%, about 55% to about 80%, about 60% to about 100%, or the like. %, about 60% to about 95%, about 60% to about 90%, about 60% to about 85%, about 60% to about 80%, about 65% to about 100%, about 65% to about 95%, about 65% to about 90%, about 65% to about 85%, about 70% to about 100%, about 70% to about 95%, about 70% to about 90%, about 70% to about 85%, about 75% to about 100%, about 75% to about 95%, and about 80% to about 100%.

[0085] In some embodiments, the proportion of water in the aqueous solvent is greater than 50%, greater than 55%, greater than 60%, greater than 65%, greater than 70%, greater than 75%, greater than 80%, greater than 85%, greater than 90%, or greater than 95% by weight. In some embodiments, the proportion of water in the aqueous solvent is less than 55%, less than 60%, less than 65%, less than 70%, less than 75%, less than 80%, less than 85%, less than 90%, or less than 95% by weight. In some embodiments, the aqueous solvent consists exclusively of water. That is, the proportion of water in the aqueous solvent is 100% by weight.

[0086] Any water-miscible or volatile solvent can be used as a minor component of the aqueous solvent (i.e., a solvent other than water). Some non-limiting examples of water-miscible or volatile solvents include alcohols, lower aliphatic ketones, lower alkyl acetates, and combinations thereof. The addition of alcohols can improve the processability of slurries formed therefrom and lower the freezing point of water. Some non-limiting examples of alcohols include C1-C4 alcohols such as methanol, ethanol, isopropanol, n-propanol, tertiary butanol, n-butanol, 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.

[0087] In some embodiments, the weight ratio of water to minor component is from about 51:49 to about 99:1, from about 53:47 to about 99:1, from about 55:45 to about 99:1, from about 57:43 to about 99:1, from about 59:41 to about 99:1, from about 61:39 to about 99:1, from about 61:39 to about 98:2, from about 61:39 to about 96:4, from about 61:39 to about 94:6, from about 61:39 to about 92:8 , from about 61:39 to about 90:10, from about 63:37 to about 90:10, from about 65:35 to about 90:10, from about 67:33 to about 90:10, from about 69:31 to about 90:10, from about 71:29 to about 90:10, from about 71:29 to about 88:12, from about 71:29 to about 86:14, from about 71:29 to about 84:16, from about 71:29 to about 82:18, or from about 71:29 to about 80:20. In some embodiments, the weight ratio of water to minor component is less than 100:1, less than 95:5, less than 90:10, less than 85:15, less than 80:20, less than 75:25, less than 70:30, less than 65:35, less than 60:40, or less than 55:45. In some embodiments, the weight ratio of water to minor component is greater than 55:45, greater than 60:40, greater than 65:35, greater than 70:30, greater than 75:25, greater than 80:20, greater than 85:15, greater than 90:10, or greater than 95:5. In some embodiments, the aqueous solvent does not comprise a minor component.

[0088] In certain embodiments, the lithium compound is a compound represented by formula (1). [ka]

[0089] where cation A + Li + where a is an integer from 1 to 10, and the anion B a- is an oxidizable anion.

[0090] In some embodiments, the anion B a- represents any anion that can lose an electron when exposed to an electrochemical potential. In some embodiments, the anion B a- is an oxidizable anion selected from the group consisting of azide anion, nitrite anion, chloride anion, delta anion, squarate anion, croconic acid anion, rhodizonate anion, ketomalonate anion, diketosuccinic acid anion, hydrazide anion, and combinations thereof. In some embodiments, the anion B a- is an oxocarbon anion.

[0091] In certain embodiments, the lithium compound is lithium azide (LiN), lithium nitrite (LiNO), lithium chloride (LiCl), lithium delta (LiC0), lithium squarate (LiC0), lithium croconic acid (LiC0), lithium rhodizonate (LiC0), lithium ketomalonate (LiC0), lithium diketosuccinic acid (LiC0), lithium hydrazide, lithium fluoride (LiF), lithium bromide (Li Br), lithium iodide (LiI), lithium sulfite (Li2SO3), lithium clear gypsum (Li2SeO3), lithium nitrate (LiNO3), lithium acetate (CH3COOLi), lithium salt of 3,4-dihydroxybenzoic acid (Li2DHBA), lithium salt of 3,4-dihydroxybutyric acid, lithium formate, lithium hydroxide (LiOH), lithium dodecyl sulfate, lithium succinate, lithium citrate, and combinations thereof.

[0092] In some embodiments, the lithium compound is selected from the group of lithium salts of organic acids RCOOLi (where R is an alkyl, benzyl, or aryl group), lithium salts of organic acids carrying more than one carboxylic acid group, such as oxalic acid, citric acid, fumaric acid, etc., and lithium salts of multiply substituted benzene rings containing carboxyl, such as trimellitic acid, 1,2,4,5-benzenetetracarboxylic acid, mellitic acid, etc.

[0093] In one embodiment, the lithium compound is a compound represented by formula (2). [ka]

[0094] Here, n is an integer from 1 to 5, and R represents lithium (Li) or hydrogen (H).

[0095] In certain embodiments, the lithium compound is a compound represented by formula (3). [ka]

[0096] Here, n is an integer from 1 to 5, and R represents lithium (Li) or hydrogen (H).

[0097] Figure 2a shows the distribution of lithium squarate with the cathode active material NMC811 prepared via an aqueous solvent-based slurry at 10,000x magnification. Figures 2b and 2c show the distribution of lithium squarate with the cathode active material NMC811 prepared using a solvent-free dry method at 10,000x magnification and 400x magnification, respectively. From the figures, it can be seen that the cathode active material particles have diameters on the order of 10 micrometers. In the mixture prepared via the aqueous solvent-based slurry shown in Figure 2a, the lithium squarate, which is soluble in aqueous solvent, is well dispersed in the cathode active material. More specifically, small particles of lithium squarate with lengths on the order of 1 micrometer can be seen adhering to the cathode active material particles. This is not observed in the mixture prepared without a solvent, as shown in Figure 2b. Instead, at lower magnification, as shown in Figure 2c, it can be seen that the lithium squarate significantly aggregates and fails to disperse properly in the solvent-free mixture, forming flakes on the order of 10 microns in length, with some flakes on the order of 100 microns in length. This indicates that the lithium compound in the aqueous solvent-based cathode slurry of the present invention, and therefore the cathode, does not agglomerate and maintains a high and stable level of dispersion. This not only assists cathodes made therefrom in maintaining high electrical conductivity, but also ensures that a consistent distribution of small, uniformly sized pores is formed in the cathode during the first charge, improving the electrochemical performance of lithium-ion batteries.

[0098] Figures 3a and 3b show the cathode surface morphology by SEM at 1,000x magnification for a cathode containing lithium nickel manganese oxide (LNMO) as the cathode active material, lithium compound, and lithium oxalate, and prepared via an aqueous solvent-based slurry. More specifically, Figure 3a depicts the surface morphology before cycling, while Figure 3b depicts the surface morphology after the first charge / discharge cycle. As shown, before cycling, the surface is fairly uniform, and after the first cycle, small, uniformly distributed pores can be seen on the surface. This indicates that the aqueous solvent-based cathode slurry as disclosed by the present invention is very well dispersed, thereby forming a cathode with excellent uniformity.

[0099] Figures 3c and 3d show the cathode surface morphology by SEM at 1,000x magnification for a cathode containing lithium nickel manganese oxide (LNMO) as the cathode active material, lithium compound, and lithium oxalate, and prepared via an organic solvent-based slurry. More specifically, Figure 3c depicts the surface morphology before cycling, while Figure 3d depicts the surface morphology after the first charge / discharge cycle. As shown, before cycling, the lithium compound tends to clump, and homogeneous distribution of the lithium compound is not achieved. This is attributed to poor dispersion of the cathode slurry material within the NMP solvent due to the insolubility of the lithium compound in organic solvents. After the first cycle, a non-uniform distribution of relatively large, variable-sized pores in the cathode can be seen, indicating that the use of an organic solvent slurry to form such a cathode slurry leads to poor cathode uniformity.

[0100] A substantial increase in resistance within the cathode results when using an organic solvent (such as NMP) as the solvent used to prepare the cathode, within a factor of at least four of the resistance without the lithium compound incorporated (Comparative Example 5 compared to Comparative Example 6). This essentially reduces the electrical conductivity of the cathode. In areas where it is more difficult for lithium ions to reach or extract, full utilization of the cathode active material cannot be realized, and the rated capacity of the cathode subsequently decreases, harming the electrochemical performance of the battery.

[0101] For the reasons stated above, the presence of lithium compounds in cathodes prepared using dry methods or via organic solvent-based cathode slurries is not recommended. Instead, aqueous solvent-based cathode slurries are specifically recommended for the production of cathode layers incorporating lithium compounds.

[0102] Many lithium compounds are hygroscopic in nature or even supplied in the form of an aqueous solution. For conventional cathode fabrication methods using slurries primarily using organic solvents such as NMP as the solvent, the use of such lithium compounds often requires an additional drying process to remove water. However, when an aqueous solvent-based slurry is used to produce the cathode of the present invention, the lithium compounds can be easily dissolved in an aqueous solvent such as water and homogeneously distributed with the cathode active material and binder material (and conductive agent).

[0103] Because the lithium compound is soluble in the aqueous solvent-based cathode slurry, it dissolves, forming the lithium cations and anions contained therein. If the lithium ion concentration of the lithium compound in the aqueous solvent-based cathode slurry is less than that required to completely eliminate irreversible lithium ion loss, irreversible capacity loss simply decreases. If the lithium ion concentration of the lithium compound in the aqueous solvent-based cathode slurry is greater than that required, the additional lithium ions are considered redundant because they cannot participate in the electrochemical reaction by fully occupying the lattice structure that holds the lithium ions. Lithium plating on the anode can also occur, leading to reduced electrochemical performance of the battery. Furthermore, retained plating can form lithium dendrites, which, if they come into contact with the cathode, can lead to a short circuit and are therefore highly dangerous and should be avoided at all costs.

[0104] The lithium ion concentration of the lithium compound in the aqueous solvent-based cathode slurry of the present invention not only affects the extent of lithium ion loss due to SEI formation during the first charge, but also controls the porosity of the cathode after the first charge. During the first charge, the lithium compound undergoes decomposition and forms pores within the cathode structure. An increase in the lithium ion concentration of the lithium compound in the aqueous solvent-based cathode slurry inevitably causes an increase in the concentration of anions, and therefore, more pores are formed in the cathode structure after the first charge, resulting in higher porosity.

[0105] A higher porosity cathode structure provides significantly increased cathode surface area and improves the efficiency of electrolyte diffusion in the cathode. However, increased cathode porosity can result in decreased electrical conductivity within the cathode. Therefore, there is a limit to the lithium ion concentration provided by the lithium compound in the cathode slurry.

[0106] Lithium ion (Li) transport by lithium compounds in aqueous solvent-based cathode slurries + The ) concentration should be sufficient and approximately equivalent to the amount of irreversible lithium ion loss by the cathode active material of the cathode due to SEI formation on the first charge.

[0107] In some embodiments, the lithium ion concentration from the lithium compound in the aqueous solvent-based cathode slurry is from about 0.005M to about 3.5M, from about 0.01M to about 3.5M, from about 0.02M to about 3.5M, from about 0.05M to about 3.5M, from about 0.1M to about 3.5M, from about 0.2M to about 3.5M, from about 0.3M to about 3.5M, from about 0.5M to about 3.5M, from about 0.7M to about 3.5M, from about 0.9M to about 3.5M, from about 0.9M to about 3.25M, from about 0.9M to about 3M, from about 0.9M to about 2.75M, from about 0.9M to about 2.5M, from about 0.9M to about 2.25M, from about 0.9M to about 2M, from about 0.9M to about 1M, up to 0.75M, from about 0.9M to about 1.5M, from about 0.9M to about 1.3M, from about 0.005M to about 2.5M, from about 0.01M to about 2.5M, from about 0.02M to about 2.5M, from about 0.05M to about 2.5M, from about 0.1M to about 2.5M, from about 0.2M to about 2.5M, from about 0.3M to about 2.5M, from about 0.5M from about 0.7M to about 2.5M, from about 0.005M to about 2M, from about 0.01M to about 2M, from about 0.02M to about 2M, from about 0.05M to about 2M, from about 0.1M to about 2M, from about 0.2M to about 2M, from about 0.3M to about 2M, from about 0.5M to about 2M, or from about 0.7M to about 2M.

[0108] In some embodiments, the lithium ion concentration from the lithium compounds in the aqueous solvent-based cathode slurry is less than 3.5M, less than 3.25M, less than 3M, less than 2.75M, less than 2.5M, less than 2.25M, less than 2M, less than 1.75M, less than 1.5M, less than 1.3M, less than 1.1M, less than 0.9M, less than 0.7M, less than 0.5M, less than 0.3M, less than 0.2M, or less than 0.1M. In some embodiments, the lithium ion concentration from the lithium compound in the aqueous solvent-based cathode slurry is greater than 0.005M, greater than 0.01M, greater than 0.02M, greater than 0.05M, greater than 0.1M, greater than 0.2M, greater than 0.3M, greater than 0.3M, greater than 0.5M, greater than 0.7M, greater than 0.9M, greater than 1.1M, greater than 1.3M, greater than 1.5M, greater than 1.75M, greater than 2M, greater than 2.25M, or greater than 2.5M.

[0109] As explained, it is important that the lithium compound be soluble in the aqueous solvent-based cathode slurry because this ensures good distribution of the lithium compound in the cathode layer. In some embodiments, the units of both the molar solubility (e.g., mol / L) and moles per unit volume (e.g., also mol / L) are the same, and therefore the solubility ratio is dimensionless. In some embodiments, the dimensionless solubility ratio of the lithium compound is from about 4000 to about 1, from about 3500 to about 1, from about 3000 to about 1, from about 2500 to about 1, from about 2000 to about 1, from about 1500 to about 1, from about 1250 to about 1, from about 1000 to about 1, from about 750 to about 1, from about 500 to about 1, from about 400 to about 1, from about 300 to about 1, from about 200 to about 1, from about 100 to about 1, from about 75 to about 1, from about 50 to about 1, from about 25 to about 1, from about 1000 to about 10, from about 1000 to about 15 , about 1000 to about 20, about 1000 to about 25, about 1000 to about 50, about 1000 to about 75, about 1000 to about 100, about 1000 to about 200, about 1000 to about 300, about 1000 to about 400, about 1000 to about 500, about 1000 to about 750, about 200 to about 2, about 200 to about 5, about 200 to about 10, about 200 to about 15, about 200 to about 20, about 200 to about 25, about 200 to about 50, about 200 to about 75, or about 200 to about 100.

[0110] In some embodiments, the dimensionless solubility ratio of the lithium compound is greater than 1, greater than 2, greater than 5, greater than 10, greater than 15, greater than 20, greater than 25, greater than 50, greater than 75, greater than 100, greater than 200, greater than 300, greater than 400, greater than 500, greater than 750, greater than 1000, greater than 1250, greater than 1500, or greater than 2000. In some embodiments, the dimensionless solubility ratio of the lithium compound is less than 4000, less than 3500, less than 3000, less than 2500, less than 2000, less than 1500, less than 1250, less than 1000, less than 750, less than 500, less than 400, less than 300, less than 200, less than 100, less than 75, less than 50, less than 25, less than 20, or less than 15.

[0111] As explained, it is also important that the lithium compound decompose within the operating potential window of the cathode active material. This ensures that the lithium cations in the lithium compound can be released to increase the lithium ion capacity of a battery containing a cathode comprising such a lithium compound. Table 1 shows the decomposition voltages of several lithium compounds realized by the present invention. In some embodiments, the decomposition voltage of the lithium compound is from about 3.0 V to about 5.0 V, from about 3.1 V to about 5.0 V, from about 3.2 V to about 5.0 V, from about 3.2 V to about 4.9 V, from about 3.2 V to about 4.8 V, from about 3.2 V to about 4.7 V, from about 3.2 V to about 4.6 V, about 3.2V to about 4.5V, about 3.2V to about 4.4V, about 3.2V to about 4.3V, about 3.2V to about 4.2V, about 3.3V to about 4.2V, about 3.4V to about 4.2V, about 3.5V to about 4.5V, about 3.6V to about 4.8V, or about 3.2V to about 4.6V.

[0112] In some embodiments, the decomposition voltage of the lithium compound is greater than 3.0 V, greater than 3.1 V, greater than 3.2 V, greater than 3.3 V, greater than 3.4 V, greater than 3.5 V, greater than 3.6 V, greater than 3.7 V, greater than 3.8 V, greater than 3.9 V, greater than 4.0 V, greater than 4.1 V, or greater than 4.2 V. In some embodiments, the decomposition voltage of the lithium compound is less than 5.0 V, less than 4.9 V, less than 4.8 V, less than 4.7 V, less than 4.6 V, less than 4.5 V, less than 4.4 V, less than 4.3 V, less than 4.2 V, less than 4.1 V, less than 4.0 V, less than 3.9 V, less than 3.8 V, less than 3.7 V, less than 3.6 V, or less than 3.5 V.

[0113] The lithium ion concentration can be controlled by varying the concentration of the lithium compound in the aqueous solvent-based cathode slurry, as well as by selecting the lithium compound used, since one formula unit of a lithium compound containing multiple lithium ions will produce multiple units of lithium ions. The amount of lithium compound in the aqueous solvent-based cathode slurry of the present invention directly affects the extent to which lithium ion loss due to SEI formation is compensated for during the first charge of the battery, and further critically affects battery performance.

[0114] In certain embodiments, the percentage of the lithium compound in the first suspension is from about 0.01% to about 40%, from about 0.025% to about 40%, from about 0.05% to about 40%, from about 0.1% to about 40%, from about 0.25% to about 40%, from about 0.5% to about 40%, from about 1% to about 40%, from about 2% to about 40%, from about 4% to about 40%, from about 4% to about 35%, from about 4% to about 30%, from about 4% to about 25%, from about 4% to about 20%, from about 4% to about 15%, from about 4% to about 10%, from about 4% to about 8%, or from about 4% to about 6% by weight, based on the total weight of the first suspension.

[0115] In some embodiments, the percentage of lithium compounds in the first suspension is less than 40%, less than 35%, less than 30%, less than 25%, less than 20%, less than 15%, less than 10%, less than 8%, less than 6%, less than 4%, less than 2%, less than 1%, less than 0.5%, or less than 0.25% by weight, based on the total weight of the first suspension. In some embodiments, the percentage of lithium compounds in the first suspension is greater than 0.01%, greater than 0.025%, greater than 0.05%, greater than 0.1%, greater than 0.25%, greater than 0.5%, greater than 1%, greater than 2%, greater than 4%, greater than 6%, greater than 8%, greater than 10%, greater than 15%, or greater than 20% by weight, based on the total weight of the first suspension.

[0116] In some embodiments, the concentration of the lithium compound in the aqueous solvent-based cathode slurry is from about 0.005M to about 2M, from about 0.01M to 2M, from about 0.02M to about 2M, from about 0.05M to about 2M, from about 0.1M to about 2M, from about 0.15M to about 2M, from about 0.2M to about 2M, from about 0.25M to about 2M, from about 0.3M to about 2M, from about 0.3M to about 1.8M, from about 0.3M to about 1.6M, from about 0.3M to about 1.4M, from about 0.3M to about 1.2M, from about 0.3M to about 1M, from about 0.3M to about 0.8M, from about 0.3M to about 0.6M, or from about 0.3M to about 0.5M.

[0117] In some embodiments, the concentration of the lithium compound in the aqueous solvent-based cathode slurry is less than 2M, less than 1.8M, less than 1.6M, less than 1.4M, less than 1.2M, less than 1M, less than 0.8M, less than 0.6M, less than 0.5M, less than 0.4M, less than 0.3M, less than 0.25M, less than 0.2M, less than 0.15M, less than 0.1M, less than 0.05M, or less than 0.02M. In some embodiments, the concentration of the lithium compound in the aqueous solvent-based cathode slurry is greater than 0.005M, greater than 0.01M, greater than 0.02M, greater than 0.05M, greater than 0.1M, greater than 0.15M, greater than 0.2M, greater than 0.25M, greater than 0.3M, greater than 0.4M, greater than 0.5M, greater than 0.6M, greater than 0.8M, greater than 1M, greater than 1.2M, greater than 1.4M, or greater than 1.6M.

[0118] In some embodiments, the first suspension is agitated at a speed of from about 10 rpm to about 600 rpm, from about 50 rpm to about 600 rpm, from about 100 rpm to about 600 rpm, from about 150 rpm to about 600 rpm, from about 200 rpm to about 600 rpm, from about 250 rpm to about 600 rpm, from about 300 rpm to about 600 rpm, from about 300 rpm to about 550 rpm, from about 320 rpm to about 550 rpm, from about 340 rpm to about 550 rpm, from about 360 rpm to about 550 rpm, from about 380 rpm to about 550 rpm, or from about 400 rpm to about 550 rpm.

[0119] In some embodiments, the first suspension is stirred at a speed of less than 600 rpm, less than 550 rpm, less than 500 rpm, less than 450 rpm, less than 400 rpm, less than 350 rpm, less than 300 rpm, less than 250 rpm, less than 200 rpm, less than 150 rpm, less than 100 rpm, or less than 50 rpm. In some embodiments, the first suspension is stirred at a speed of greater than 10 rpm, greater than 50 rpm, greater than 100 rpm, greater than 150 rpm, greater than 200 rpm, greater than 250 rpm, greater than 300 rpm, greater than 350 rpm, greater than 400 rpm, greater than 450 rpm, greater than 500 rpm, or greater than 550 rpm.

[0120] In some embodiments, the second suspension is formed by adding a binder to the first suspension in step 102. In some embodiments, the binder is a copolymer binder. In some embodiments, the binder is a water-compatible copolymer binder. In some embodiments, the second suspension further comprises a conductive agent.

[0121] The water-compatible copolymer binder has excellent adhesion capacity, allowing the cathode layer to be strongly adhered to the current collector. More importantly, as the name suggests, the water-compatible copolymer binder disperses well in the aqueous solvent-based cathode slurry, ensuring good binding ability of the binder to various cathode layer materials. The good binding ability of the water-compatible copolymer binder to various cathode layer materials results in reduced interfacial resistance between the various components of the cathode layer, thereby ensuring good ionic and electrical conductivity of the cathode layer. Therefore, the good dispersion and binding ability of the water-compatible copolymer binder in the aqueous solvent-based cathode slurry reduces capacity loss due to uneven distribution of cathode layer components within the cathode layer and ensures uniform lithiation of the cathode layer with lithium compounds throughout the cathode layer. When producing cathodes, good dispersion of the water-compatible copolymer binder in the aqueous-solvent-based cathode slurry also ensures a smooth and uniform coating of the slurry on the current collector, thereby reducing capacity loss due to cathode roughness. Therefore, the selection of the binder used in the cathode slurry is critical to the electrochemical and mechanical performance of batteries containing cathodes produced with such slurries. When a water-compatible copolymer binder is used in the aqueous-solvent-based cathode slurry, batteries containing cathodes produced with such slurries have excellent electrochemical and mechanical performance, especially compared to binders that are not water-compatible, as well as binders that are water-compatible but not copolymeric in nature.

[0122] In some embodiments, the water-compatible copolymer binder comprises a structural unit (a), wherein the structural unit (a) is derived from a monomer selected from the group consisting of a monomer containing a carboxylic acid group, a monomer containing a carboxylate group, a monomer containing a sulfonic acid group, a monomer containing a sulfonate group, a monomer containing a phosphonic acid group, a monomer containing a phosphonate group, and combinations thereof. In some embodiments, the acid salt group is a salt of an acid group. In some embodiments, the acid salt group-containing monomer comprises an alkali metal cation. Examples of alkali metals that form alkali metal cations include lithium, sodium, and potassium. In some embodiments, the acid salt group-containing monomer comprises an ammonia cation. In some embodiments, the structural unit (a) can be derived from a combination of a monomer containing a base and a monomer containing an acid group.

[0123] In some embodiments, the monomer comprising a carboxylic acid group is acrylic acid, methacrylic acid, crotonic acid, 2-butyl crotonic acid, cinnamic acid, maleic acid, maleic anhydride, fumaric acid, itaconic acid, itaconic anhydride, tetraconic acid, or a combination thereof. In some embodiments, the monomer containing a carboxylic acid group is 2-ethylacrylic acid, isocrotonic acid, cis-2-pentenoic acid, trans-2-pentenoic acid, angelic acid, tiglic acid, 3,3-dimethyl acrylic acid, 3-propyl acrylic acid, trans-2-methyl-3-ethyl acrylic acid, cis-2-methyl-3-ethyl acrylic acid, 3-isopropyl acrylic acid, trans-3-methyl-3-ethyl acrylic acid, cis-3-methyl-3-ethyl acrylic acid, acrylic acid, 2-isopropyl acrylic acid, trimethyl acrylic acid, 2-methyl-3,3-diethyl acrylic acid, 3-butyl acrylic acidacid, 2-butyl acrylic acid, 2-pentyl acrylic acid, 2-methyl-2-hexenoic acid, trans-3-methyl-2-hexenoic acid, 3-methyl-3-propyl acrylic acid, 2-ethyl-3-propyl acrylic acid, 2,3-diethyl acrylic acid, 3,3-diethyl acrylic acid, 3-methyl-3-hexyl acrylic acid, 3-methyl-3-tert-butyl acrylic acid, 2-methyl-3-pentyl acrylic acid acid, 3-methyl-3-pentyl acrylic acid, 4-methyl-2-hexenoic acid, 4-ethyl-2-hexenoic acid, 3-methyl-2-ethyl-2-hexenoic acid, 3-tert-butyl acrylic acid, 2,3-dimethyl-3-ethyl acrylic acid, 3,3-dimethyl-2-ethyl acrylic acid, 3-methyl-3-isopropyl acrylic acid, 2-methyl-3-isopropyl acrylic acid, trans-2-octenoic acidThe acrylic acid may be cis-2-octenoic acid, trans-2-decenoic acid, α-acetoxyacrylic acid, β-trans-aryloxyacrylic acid, α-chloro-β-E-methoxyacrylic acid, or a combination thereof. In some embodiments, the monomer comprising a carboxylic acid group is methyl maleic acid, dimethyl maleic acid, phenyl maleic acid, bromo maleic 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 monomer containing a carboxylic acid group is maleic anhydride, methyl maleic anhydride, dimethyl maleic anhydride, acrylic anhydride, methacrylic anhydride, methacrolein, methacryloyl chloride, or the like.The compound may be methacryloyl chloride, methacryloyl fluoride, methacryloyl bromide, or a combination thereof.

[0124] In some embodiments, the monomer containing a carboxylate group is an acrylic acid salt, a methacrylic acid salt, a crotonic acid salt, a 2-butyl crotonic acid salt, a cinnamic acid salt, a maleic acid salt, a maleic anhydride salt, a fumaric acid salt, an itaconic acid salt, an itaconic anhydride salt, a tetraconic acid salt, or a combination thereof. In some embodiments, the monomer containing a carboxylate group is 2-ethylacrylic acid salt, isocrotonic acid salt, cis-2-pentenoic acid salt, trans-2-pentenoic acid salt, angelic acid salt, tiglic acid salt, 3,3-dimethylacrylate (3,3-dimethyl acrylic acid salt, 3-propyl acrylic acid salt, trans-2-methyl-3-ethyl acrylic acid salt, cis-2-methyl-3-ethyl acrylic acid salt, 3-isopropyl acrylic acid salt, trans-3-methyl-3-ethyl acrylic acid salt, cis-3-methyl-3-ethyl acrylic acid salt, 2-isopropyl acrylic acid salt, trimethyl acrylic acid salt, 2-methyl-3,3-diethyl acrylic acid salt, 3-butyl acrylic acid salt, 2-butyl acrylic acid salt salt), 2-pentyl acrylic acid salt, 2-methyl-2-hexenoic acid salt, trans-3-methyl-2-hexenoic acid salt, 3-methyl-3-propyl acrylic acid salt, 2-ethyl-3-propyl acrylic acid salt, 2,3-diethyl acrylic acid salt, 3,3-diethyl acrylic acid salt3-diethyl acrylic acid salt, 3-methyl-3-hexyl acrylic acid salt, 3-methyl-3-tert-butyl acrylic acid salt, 2-methyl-3-pentyl acrylic acid salt, 3-methyl-3-pentyl acrylic acid salt, 4-methyl-2-hexenoic acid salt, 4-ethyl-2-hexenoic acid salt, 3-methyl-2-ethyl-2-hexenoic acid salt, 3-tert-butyl acrylic acid salt, 2,3-dimethyl-3-ethyl acrylic acid salt salt), 3,3-dimethyl-2-ethyl acrylic acid salt, 3-methyl-3-isopropyl acrylic acid salt, 2-methyl-3-isopropyl acrylic acid salt, trans-2-octenoic acid salt, cis-2-octenoic acid salt, trans-2-dectenoic acid salt, α-acetoxyacrylic acid salt,), β-trans-aryloxyacrylic acid salt, α-chloro-β-E-methoxyacrylic acid salt, or a combination thereof. In some embodiments, the monomer containing a carboxylate group is methyl maleic acid salt, dimethyl maleic acid salt, phenyl maleic acid salt, bromo maleic acid salt, chloromaleic acid salt, dichloromaleic acid salt, fluoromaleic acid salt, difluoromaleic acid salt, or a combination thereof.

[0125] In some embodiments, the sulfonate group-containing monomer is vinylsulfonic acid, methylvinylsulfonic acid, allylvinylsulfonic acid, arylsulfonic acid, methallylsulfonic acid, styrenesulfonic acid, 2-sulfoethyl methacrylic acid, 2-methylprop-2-ene-1-sulfonic acid, 2-acrylamido-2-methyl-1-propane sulfonic acid, 3-allyloxy-2-hydroxy-1-propane sulfonic acid, or a combination thereof.

[0126] In some embodiments, the sulfonate group-containing monomer is vinylsulfonic acid salt, methylvinylsulfonic acid salt, allylvinylsulfonic acid salt, arylsulfonic acid salt, methylarylsulfonic acid salt, styrenesulfonic acid salt, 2-sulfoethyl methacrylic acid salt, 2-methylprop-2-ene-1-sulfonic acid salt, 2-acrylamido-2-methyl-1-propane sulfonic acid salt, 3-allyloxy-2-hydroxy-1-propane sulfonic acid salt, or a combination thereof.

[0127] In some embodiments, the monomer comprising a phosphonic acid group is vinyl phosphonic acid, allyl phosphonic acid, vinyl benzyl phosphonic acid, acrylamide alkyl phosphonic acid, methacrylamide alkyl phosphonic acid, acrylamide alkyl diphosphonic acid, acryloylphosphonic acid, 2-methacryloyloxyethyl phosphonic acid, bis(2-methacryloyloxyethyl) phosphonic acid, ethylene 2-methacryloyloxyethyl phosphonic acid, acid, ethyl-methacryloyloxyethyl phosphonic acid, or a combination thereof.

[0128] In some embodiments, the monomer comprising a phosphonate group is a salt of vinylphosphonic acid, a salt of arylphosphonic acid, a salt of vinylbenzylphosphonic acid, a salt of acrylamidoalkylphosphonic acid, a salt of methacrylamidoalkylphosphonic acid, a salt of acrylamidoalkyldiphosphonic acid, a salt of acryloylphosphonic acid, a salt of 2-methiacryloxyethylphosphonic acid, a salt of bis(2-methiacryloxyethyl)phosphonic acid, a salt of ethylene 2-methiacryloxyethylphosphonic acid, a salt of ethyl-methiacryloxyethylphosphonic acid, or a combination thereof.

[0129] In some embodiments, the proportion of structural unit (a) in the water-compatible copolymer binder, based on the total moles of monomer units in the water-compatible copolymer binder, is from about 15% to about 80%, from about 17.5% to about 80%, from about 20% to about 80%, from about 22.5% to about 80%, from about 25% to about 80%, from about 27.5% to about 80%, from about 30% to about 80%, from about 32.5% to about 80%, from about 35% to about 80%, from about 37.5% to about 80%, by mole. up to about 80%, from about 40% to about 80%, from about 42.5% to about 80%, from about 45% to about 80%, from about 45% to about 77.5%, from about 45% to about 75%, from about 45% to about 72.5%, from about 45% to about 70%, from about 45% to about 67.5%, from about 45% to about 65%, from about 45% to about 62.5%, from about 45% to about 60%, from about 45% to about 57.5%, from about 45% to about 55%, from about 45% to about 52.5%, or from about 45% to about 50%.

[0130] In some embodiments, the proportion of structural units (a) in the water-compatible copolymer binder is less than 80%, less than 77.5%, less than 75%, less than 72.5%, less than 70%, less than 67.5%, less than 65%, less than 62.5%, less than 60%, less than 57.5%, less than 55%, less than 52.5%, less than 50%, less than 47.5%, less than 45%, less than 42.5%, less than 40%, less than 37.5%, less than 35%, less than 32.5%, less than 30%, less than 27.5%, or less than 25%, by mole, based on the total moles of monomer units in the water-compatible copolymer binder. In some embodiments, the proportion of structural units (a) in the water-compatible copolymer binder is greater than 15%, greater than 17.5%, greater than 20%, greater than 22.5%, greater than 25%, greater than 27.5%, greater than 30%, greater than 32.5%, greater than 35%, greater than 37.5%, greater than 40%, greater than 42.5%, greater than 45%, greater than 47.5%, greater than 50%, greater than 52.5%, greater than 55%, greater than 57.5%, greater than 60%, greater than 62.5%, greater than 65%, greater than 67.5%, or greater than 70%, by mole, based on the total moles of monomer units in the water-compatible copolymer binder.

[0131] In some embodiments, the water-compatible copolymer binder further comprises structural unit (b), wherein structural unit (b) is derived from a monomer selected from the group consisting of a monomer containing an amide group, a monomer containing a hydroxyl group, and combinations thereof.

[0132] In some embodiments, the monomer comprising an amide group is acrylamide, methacrylamide, N-methyl methacrylamide, N-ethyl methacrylamide, Nn-propyl methacrylamide, N-isopropyl methacrylamide, isopropyl acrylamide, Nn-butyl methacrylamide, N-isobutyl methacrylamide, N,N-dimethyl acrylamide, N,N-dimethyl methacrylamide, N,N-diethyl acrylamide, N,N-diethyl methacrylamide. methacrylamide, N-methylol methacrylamide, N-(methoxymethyl)methacrylamide, N-(ethoxymethyl)methacrylamide, N-(propoxymethyl)methacrylamide, N-(butoxymethyl)methacrylamide, N,N-dimethyl methacrylamide, N,N-dimethylaminopropyl methacrylamide, N,N-dimethylaminoethyl methacrylamide, N,N-dimethylol methacrylamideN-dimethylol methacrylamide, diacetone methacrylamide, diacetone acrylamide, methacryloyl morpholine, N-hydroxyl methacrylamide, N-methoxymethyl acrylamide, N-methoxymethyl methacrylamide, N,N'-methylene-bis-acrylamide (MBA), N-hydroxymethyl acrylamide, or a combination thereof.

[0133] In some embodiments, the hydroxyl group-containing monomer has a hydroxy group and is C1 to C 20 Alkyl groups from C5 to C 20In some embodiments, the hydroxyl group-containing monomer is 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 2-hydroxybutyl methacrylate, 3-hydroxypropyl acrylate, 3-hydroxypropyl methacrylate, 4-hydroxybutyl methacrylate, 5-hydroxypentyl acrylate, 6-hydroxyhexyl methacrylate, 1,4-cyclohexanedimethanol mono(meth)acrylate, 3-chloro-2 ...4-hydroxybutyl methacrylate, 5-hydroxypentyl acrylate, 6-hydroxyhexyl methacrylate, 4-hydroxybutyl methacrylate, 5-hydroxypentyl acrylate, 6-hydroxyhexyl methacrylate, 4-hydroxybutyl methacrylate, 5- The polymer may be selected from the group consisting of diethylene glycol mono(meth)acrylate, diethylene glycol mono(meth)acrylate, allyl alcohol, and combinations thereof.

[0134] In some embodiments, the proportion of structural units (b) in the water-compatible copolymer binder is from about 5% to about 35%, from about 7% to about 35%, from about 9% to about 35%, from about 11% to about 35%, from about 13% to about 35%, from about 15% to about 35%, from about 17% to about 35%, from about 17% to about 33%, from about 17% to about 31%, from about 17% to about 29%, from about 17% to about 27%, from about 17% to about 25%, or from about 17% to about 23%, by mole, based on the total moles of monomer units in the water-compatible copolymer binder.

[0135] In some embodiments, the proportion of structural units (b) in the water-compatible copolymer binder is less than 35%, less than 33%, less than 31%, less than 29%, less than 27%, less than 25%, less than 23%, less than 21%, less than 19%, less than 17%, or less than 15%, by mole, based on the total moles of monomer units in the water-compatible copolymer binder. In some embodiments, the proportion of structural units (b) in the water-compatible copolymer binder is greater than 5%, greater than 7%, greater than 9%, greater than 11%, greater than 13%, greater than 15%, greater than 17%, greater than 19%, greater than 21%, greater than 23%, or greater than 25%, by mole, based on the total moles of monomer units in the water-compatible copolymer binder.

[0136] In some embodiments, the water-compatible copolymer binder further comprises a structural unit (c), wherein the structural unit (c) is derived from a monomer selected from the group consisting of a monomer containing a nitrile group, a monomer containing an ester group, a monomer containing an epoxy group, a monomer containing fluorine, and combinations thereof.

[0137] In some embodiments, the nitrile group-containing monomer comprises an α,β-ethylenically unsaturated nitrile monomer, hi some embodiments, the nitrile group-containing monomer is acrylonitrile, α-halogenoacrylonitrile, 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-methacrylonitrile, 4-methylacrylonitrile, 5-methyl-4-methyl-5 ... acrylonitrile, 3-ethoxyacrylonitrile, α-acetoxyacrylonitrile, α-phenylacrylonitrile, α-tolylacrylonitrile, α-(methoxyphenyl)acrylonitrile, α-(chlorophenyl)acrylonitrile, α-(cyanophenyl)acrylonitrile, vinylidene cyanide, or combinations thereof.

[0138] In some embodiments, the monomer containing an ester group is C1 to C 20alkyl acrylate, C1 to C20 alkyl(meth)acrylate, cycloacrylate, or a combination thereof. In some embodiments, the monomer comprising an ester group is methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, sec-butyl acrylate, tert-butyl acrylate, pentyl acrylate, hexyl acrylate, heptyl acrylate, octyl acrylate, 3,3,5-trimethylhexyl acrylate, 2-ethylhexyl acrylate, nonyl acrylate, decyl acrylate, lauryl acrylate, n-tetradecyl acrylate, octadecyl acrylate, cyclohexyl acrylate, phenyl acrylate, methoxymethyl acrylate, methoxyethyl acrylate, ethoxymethyl acrylate, ethoxyethyl acrylate, perfluorooctyl acrylate, stearyl acrylate, or a combination thereof. In some embodiments, the monomer comprising an ester group is cyclohexyl acrylate, cyclohexyl methacrylate, isobornyl acrylate, isobornyl methacrylate, 3,3,5-trimethylcyclohexyl acrylate, or a combination thereof. In some embodiments, the monomer comprising an ester group is methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, sec-butyl methacrylate, tertiary butyl methacrylate, isobutyl methacrylate, n-pentyl methacrylate, isopentyl methacrylate, hexyl methacrylate, heptyl methacrylate, octyl methacrylate, 2-ethylhexyl methacrylate, nonyl methacrylate, decyl methacrylate, lauryl methacrylate, n-tetradecyl methacrylate, stearyl methacrylate, 2,2,2-trifluoroethyl methacrylate, phenyl methacrylate, benzyl methacrylate, or a combination thereof.

[0139] In some embodiments, the monomer comprising an epoxy group is vinyl glycidyl ether, aryl glycidyl ether, aryl 2,3-epoxypropyl ether, butenyl glycidyl ether, butadiene monoepoxide, chloroprene monoepoxide, 3,4-epoxy-1-butene, 4,5-epoxy-2-pentene, 3,4-epoxy-1-vinylcyclohexane, 1,2-epoxy-4-vinylcyclohexane, 3,4-epoxycyclohexylethylene, epoxy-4-vinylcyclohexene, 1,2-epoxy-5,9-cyclododecadiene, or a combination thereof.

[0140] In some embodiments, the epoxy group-containing monomer is 3,4-epoxy-1-butene, 1,2-epoxy-5-hexene, 1,2-epoxy-9-decene, glycidyl acrylate, glycidyl methacrylate, glycidyl crotonate, glycidyl 2,4-dimethylpentenoate, glycidyl 4-hexenoate, glycidyl 4-heptenoate, glycidyl 5-methyl-4-heptenoate, glycidyl sorbate, glycidyl linoleate, glycidyl oleate, glycidyl 3-butenoate, glycidyl 3-pentenoate, glycidyl-4-methyl-3-pentenoate, or a combination thereof.

[0141] In some embodiments, the fluorine-containing monomer is an acrylate, methacrylate, or combination thereof containing a C1 to C20 alkyl group, wherein the monomer contains at least one fluorine atom. In some embodiments, the fluorine-containing monomer is a perfluoroalkyl acrylate such as perfluorododecyl acrylate, perfluoro n-octyl acrylate, perfluoro n-butyl acrylate, perfluorohexyl ethyl acrylate, and perfluorooctyl ethyl acrylate; a perfluoroalkyl methacrylate such as perfluorododecyl methacrylate, perfluoro n-octyl methacrylate, perfluoro n-butyl methacrylate, perfluorohexyl ethyl methacrylate, and perfluorooctyl ethyl methacrylate; a perfluorooxyalkyl acrylate such as perfluorododecyloxyethyl acrylate and perfluorodecyloxyethyl acrylate; a perfluorooxyalkyl methacrylate such as perfluorododecyloxyethyl methacrylate and perfluorodecyloxyethyl methacrylate, or a combination thereof. In some embodiments, the fluorine-containing monomer is a C1 to C20 alkyl group. 20 and at least one fluorine atom, wherein the carboxylate is selected from the group consisting of its crotonate, malate, fumarate, itaconate, and combinations thereof. In some embodiments, the fluorine-containing monomer is vinyl fluoride, trifluoroethylene, trifluorochloroethylene, fluoroalkyl vinyl ether, perfluoroalkyl vinyl ether, hexafluoropropylene, 2,3,3,3-tetrafluoropropene, vinylidene fluoride, tetrafluoroethylene, 2-fluoroacrylate, or a combination thereof.

[0142] In some embodiments, the proportion of structural units (c) in the water-compatible copolymer binder is from about 15% to about 75%, from about 17.5% to about 75%, from about 20% to about 75%, from about 22.5% to about 75%, from about 25% to about 75%, from about 27.5% to about 75%, from about 30% to about 75%, from about 32.5% to about 75%, from about 35% to about 75%, from about 37.5% to about 75%, by mole, based on the total moles of monomer units in the water-compatible copolymer binder. up to about 75%, from about 40% to about 75%, from about 42.5% to about 75%, from about 42.5% to about 72.5%, from about 42.5% to about 70%, from about 42.5% to about 67.5%, from about 42.5% to about 65%, from about 42.5% to about 62.5%, from about 42.5% to about 60%, from about 42.5% to about 57.5%, from about 42.5% to about 55%, from about 42.5% to about 52.5%, from about 42.5% to about 50%, or from about 42.5% to about 47.5%.

[0143] In some embodiments, the proportion of structural units (c) in the water-compatible copolymer binder is less than 75%, less than 72.5%, less than 70%, less than 67.5%, less than 65%, less than 62.5%, less than 60%, less than 57.5%, less than 55%, less than 52.5%, less than 50%, less than 47.5%, less than 45%, less than 42.5%, less than 40%, less than 37.5%, less than 35%, less than 32.5%, less than 30%, less than 27.5%, or less than 25%, by mole, based on the total moles of monomer units in the water-compatible copolymer binder. In some embodiments, the proportion of structural units (c) in the water-compatible copolymer binder is greater than 15%, greater than 17.5%, greater than 20%, greater than 22.5%, greater than 25%, greater than 27.5%, greater than 30%, greater than 32.5%, greater than 35%, greater than 37.5%, greater than 40%, greater than 42.5%, greater than 45%, greater than 47.5%, greater than 50%, greater than 52.5%, greater than 55%, greater than 57.5%, greater than 60%, greater than 62.5%, or greater than 65%, by mole, based on the total moles of monomer units in the water-compatible copolymer binder.

[0144] In other embodiments, the water-compatible copolymer binder may further comprise structural units derived from an olefin. Any hydrocarbon having at least one carbon-carbon double bond may be used as the olefin without particular limitation. In some embodiments, the olefin is a C2 to C6 20 Aliphatic compounds, C8 to C 20 Aromatic or cyclic compounds containing vinyl unsaturation, C4 to C 40and combinations thereof. In some embodiments, the olefin is styrene, ethylene, propylene, isobutylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicosaene, 3-methyl-1-butene, cyclobutene, 3-methyl-1-pentene, 4-methyl-1-pentene, 4,6-dimethyl-1-heptene, 4-vinylcyclohexene, vinylcyclohexane, norbornene, norbornadiene, ethylidenenorbornene, cyclopentene, cyclohexene, dicyclopentadiene, cyclooctene, or a combination thereof. In some embodiments, the copolymer does not contain structural units derived from an olefin. In some embodiments, the copolymer does not contain structural units derived from styrene, ethylene, propylene, isobutylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicosaene, 3-methyl-1-butene, cyclobutene, 3-methyl-1-pentene, 4-methyl-1-pentene, 4,6-dimethyl-1-heptene, 4-vinylcyclohexene, vinylcyclohexane, norbornene, norbornadiene, ethylidenenorbornene, cyclopentene, cyclohexene, dicyclopentadiene, or cyclooctene.

[0145] The monomers containing the attached diene groups are configured as olefins. In some embodiments, the monomers containing the attached diene groups are C4 to C6 40and aliphatically linked diene monomers such as 1,3-butadiene, 1,3-pentadiene, 1,4-hexadiene, 1,5-hexadiene, 1,7-octadiene, 1,9-decadiene, isoprene, myrcene, 2-methyl-1,3-butadiene, 2,3-dimethyl-1,3-butadiene, 2-chloro-1,3-butadiene, substituted linearly linked pentadiene, substituted side-chain linked hexadiene, and combinations thereof. In some embodiments, the copolymer comprises a C4 to C6 copolymer. 40 and aliphatically linked diene monomers such as 1,3-butadiene, 1,3-pentadiene, 1,4-hexadiene, 1,5-hexadiene, 1,7-octadiene, 1,9-decadiene, isoprene, myrcene, 2-methyl-1,3-butadiene, 2,3-dimethyl-1,3-butadiene, 2-chloro-1,3-butadiene, and substituted linearly linked pentadiene or substituted side-chain linked hexadiene.

[0146] In other embodiments, the water-compatible copolymer binder may further include structural units derived from a monomer containing an aromatic vinyl group. In some embodiments, the monomer containing an aromatic vinyl group is styrene, α-methylstyrene, vinyltoluene, divinylbenzene, or a combination thereof. In some embodiments, the water-compatible copolymer binder does not include structural units derived from a monomer containing an aromatic vinyl group. In some embodiments, the water-compatible copolymer binder does not include structural units derived from styrene, α-methylstyrene, vinyltoluene, or divinylbenzene.

[0147] In certain embodiments, the proportion of the water-compatible copolymer binder in the aqueous solvent-based cathode slurry is from about 0.1% to about 10%, from about 0.1% to about 9%, from about 0.1% to about 8%, from about 0.1% to about 7%, from about 0.1% to about 6%, from about 0.1% to about 5%, from about 0.1% to about 4%, from about 0.1% to about 3%, from about 0.3% to about 5%, from about 0.3% to about 4%, from about 0.3% to about 3%, from about 0.5% to about 5%, from about 0.5% to about 4%, from about 0.5% to about 3%, from about 1% to about 5%, from about 1% to about 4%, from about 1% to about 3%, from about 1.5% to about 5%, or from about 1.5% to about 4% by weight, based on the total weight of the aqueous solvent-based cathode slurry.

[0148] In some embodiments, the proportion of the water-compatible copolymer binder in the aqueous solvent-based cathode slurry 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%, less than 2%, or less than 1% by weight, based on the total weight of the aqueous solvent-based cathode slurry. In some embodiments, the proportion of the water-compatible copolymer binder in the aqueous solvent-based cathode slurry is greater than 0.1%, greater than 0.5%, 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, based on the total weight of the aqueous solvent-based cathode slurry.

[0149] In some embodiments, the aqueous solvent-based cathode slurry can include a conductive agent. The conductive agent enhances the electrical conductivity of the electrode. Any suitable material can function as the conductive agent. In some embodiments, the conductive agent is a carbon material. Some non-limiting examples of carbon materials suitable for use as the conductive agent include carbon, carbon black, graphite, expanded graphite, graphene, graphene nanoplatelets, carbon fiber, carbon nanofiber, graphitized carbon flakes, carbon tubes, carbon nanotubes, activated carbon, Super P, zero-dimensional KS6, one-dimensional vapor-grown carbon fiber (VGCF), mesoporous carbon, and combinations thereof. In some embodiments, the conductive agent does not include a carbon material.

[0150] In some embodiments, the conductive agent is a conductive polymer selected from the group consisting of polypyrrole, polyaniline, polyacetylene, polyphenylene sulfide (PPS), polyphenylene vinylene (PPV), poly(3,4-ethylenedioxythiophene) (PEDOT), polythiophene, or a combination thereof. In some embodiments, the conductive agent simultaneously serves two roles: as a conductive agent and as a binder material. In some embodiments, the positive electrode layer includes three components: a cathode active material, a lithium compound, and a conductive polymer. In other embodiments, the positive electrode layer includes a cathode active material, a lithium compound, a conductive agent, and a conductive polymer. In some embodiments, the conductive polymer is an additive, and the positive electrode layer includes a cathode active material, a lithium compound, a conductive agent, a water-compatible copolymer binder, and a conductive polymer. In other embodiments, the conductive agent does not include a conductive polymer.

[0151] In certain embodiments, the proportion of the conductive agent in the aqueous solvent-based cathode slurry is from about 0.5% to about 5%, from about 0.5% to about 4%, from about 0.5% to about 3%, from about 1% to about 5%, from about 1% to about 4%, from about 2% to about 3%, or from about 1.5% to about 3% by weight, based on the total weight of the aqueous solvent-based cathode slurry. In some embodiments, the proportion of the conductive agent in the aqueous solvent-based cathode slurry is greater than 0.5%, greater than 1%, greater than 1.5%, greater than 2%, greater than 2.5%, greater than 3%, greater than 3.5%, greater than 4%, or greater than 4.5% by weight, based on the total weight of the aqueous solvent-based cathode slurry. In certain embodiments, the proportion of the conductive agent in the aqueous solvent-based cathode slurry is less than 5%, less than 4.5%, less than 4%, less than 3.5%, less than 3%, less than 2.5%, less than 2%, less than 1.5%, or less than 1% by weight, based on the total weight of the aqueous solvent-based cathode slurry.

[0152] In some embodiments, the weight of the water-compatible copolymer binder is greater than, less than, or equal to the weight of the conductive agent in the aqueous solvent-based cathode slurry. In certain embodiments, the ratio of the weight of the water-compatible copolymer binder to the weight of the conductive agent in the aqueous solvent-based cathode slurry is from about 1:10 to about 10:1, from about 1:10 to about 5:1, from about 1:10 to about 1:1, from about 1:10 to about 1:5, from about 1:5 to about 5:1, from about 1:3 to about 3:1, from about 1:2 to about 2:1, or from about 1:1.5 to about 1.5:1.

[0153] In some embodiments, the first and second suspensions are independently agitated at a temperature of about 5° C. to about 40° C., about 5° C. to about 35° C., about 5° C. to about 30° C., about 5° C. to about 25° C., about 5° C. to about 20° C., about 5° C. to about 15° C., about 5° C. to about 10° C., about 10° C. to about 40° C., about 10° C. to about 35° C., about 10° C. to about 30° C., about 10° C. to about 25° C., about 10° C. to about 20° C., or about 15° C. to about 35° C. In some embodiments, the first and second suspensions are independently agitated at a temperature 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 first and second suspensions are independently agitated at a temperature greater than 5°C, greater than 10°C, greater than 15°C, greater than 20°C, greater than 25°C, greater than 30°C, or greater than 35°C.

[0154] In some embodiments, the first and second suspensions are heated for about 1 minute to about 60 minutes, about 1 minute to about 50 minutes, about 1 minute to about 40 minutes, about 1 minute to about 30 minutes, about 1 minute to about 20 minutes, about 1 minute to about 10 minutes, about 5 minutes to about 60 minutes, about 5 minutes to about 50 minutes, about 5 minutes to about 40 minutes, about 5 minutes to about 30 minutes, about 5 minutes to about 20 minutes, about 5 minutes to about 10 minutes, about 10 ... The mixture is independently stirred for a period of up to about 60 minutes, from about 10 minutes to about 50 minutes, from about 10 minutes to about 40 minutes, from about 10 minutes to about 30 minutes, from about 10 minutes to about 20 minutes, from about 15 minutes to about 60 minutes, from about 15 minutes to about 50 minutes, from about 15 minutes to about 40 minutes, from about 15 minutes to about 30 minutes, from about 15 minutes to about 20 minutes, from about 20 minutes to about 50 minutes, from about 20 minutes to about 40 minutes, or from about 20 minutes to about 30 minutes.

[0155] In certain embodiments, the first and second suspensions are independently agitated for periods of less than 60 minutes, less than 55 minutes, less than 50 minutes, less than 45 minutes, less than 40 minutes, less than 35 minutes, less than 30 minutes, less than 25 minutes, less than 20 minutes, less than 15 minutes, less than 10 minutes, or less than 5 minutes. In some embodiments, the first and second suspensions are independently agitated for periods of more than 5 minutes, more than 10 minutes, more than 15 minutes, more than 20 minutes, more than 25 minutes, more than 30 minutes, more than 35 minutes, more than 40 minutes, more than 45 minutes, more than 50 minutes, or more than 55 minutes.

[0156] In some embodiments, the second suspension is rotated at a speed of from about 100 rpm to about 1500 rpm, from about 100 rpm to about 1400 rpm, from about 150 rpm to about 1400 rpm, from about 200 rpm to about 1400 rpm, from about 250 rpm to about 1400 rpm, from about 300 rpm to about 1400 rpm, from about 300 rpm to about 1300 rpm, from about 350 rpm to about 1300 rpm, from about 400 rpm to about 1300 rpm, from about 45 ... The mixture may be stirred at a speed of from 0 rpm to about 1200 rpm, from about 500 rpm to about 1200 rpm, from about 600 rpm to about 1200 rpm, from about 700 rpm to about 1400 rpm, from about 800 rpm to about 1400 rpm, from about 900 rpm to about 1400 rpm, from about 1000 rpm to about 1400 rpm, from about 300 rpm to about 1000 rpm, from about 300 rpm to about 900 rpm, from about 300 rpm to about 800 rpm, or from about 300 rpm to about 700 rpm.

[0157] In some embodiments, the second suspension is stirred at a speed of less than 1500 rpm, less than 1400 rpm, less than 1300 rpm, less than 1200 rpm, less than 1100 rpm, less than 1000 rpm, less than 900 rpm, less than 800 rpm, less than 700 rpm, less than 600 rpm, less than 500 rpm, less than 400 rpm, less than 300 rpm, or less than 200 rpm. In some embodiments, the second suspension is stirred at a speed of greater than 100 rpm, greater than 200 rpm, greater than 300 rpm, greater than 400 rpm, greater than 500 rpm, greater than 600 rpm, greater than 700 rpm, greater than 800 rpm, greater than 900 rpm, greater than 1000 rpm, greater than 1100 rpm, greater than 1200 rpm, greater than 1300 rpm, or greater than 1400 rpm.

[0158] In some embodiments, the third suspension is formed in step 103 by dispersing the cathode active material within the second suspension.

[0159] In some embodiments, the electrode active material is a cathode active material, where the cathode active material is LiCoO, LiNiO, LiNi x Mn y O2, Li 1+z Ni x Mn y Co 1-x-y O2, LiNi x Co y Al z In some embodiments, the cathode active material is selected from the group consisting of LiCoO, LiNi ... x Mn y O2, Li 1+z Ni x Mny Co 1-x-y O2(NMC), LiNi x Co y Al z In another embodiment, the cathode active material is selected from the group consisting of LiCoO2, LiNiO2, LiV2O5, LiTiS2, LiMoS2, LiMnO2, LiCrO2, LiMn2O4, LiFeO2, LiFePO4, and combinations thereof, where each x is independently from 0.4 to 0.6, each y is independently from 0.2 to 0.4, and each z is independently from 0 to 0.1. In another embodiment, the cathode active material is not LiCoO2, LiNiO2, LiV2O5, LiTiS2, LiMoS2, LiMnO2, LiCrO2, LiMn2O4, LiFeO2, or LiFePO4. In a further embodiment, the cathode active material is LiNi x Mn y O2, Li 1+z Ni x Mn y Co 1-x-y O2 or LiNi x Co y Al z where each x is independently 0.2 to 0.9, each y is independently 0.1 to 0.45, and each z is independently 0 to 0.2. In some embodiments, the cathode active material is Li 1+x Ni a Mn b Co c Al (1-a-b-c)O2, where -0.2<=x<=0.2, 0<=a<1, 0<=b<1, 0<=c<1, and a+b+c<=1. In some embodiments, the cathode active material has an ionic conductivity of 0.33<=a<=0.92, 0.33≦=a≦0.9, 0.33<=a<=0.8, 0.5<=a<=0.92, 0.5<=a<=0.9, 0.5<=a<=0.8, 0.6<=a<=0.92, or 0.6<=a<=0.9, 0<=b<=0.5, 0≦=b≦=0.3, 0. 1≦=b≦=0.5, 0.1≦=b≦=0.4, 0.1≦=b≦=0.3, 0.1≦=b≦=0.2, or 0.2≦=b≦=0.5, 0≦=c<=0.5, 0<=c<=0.3, 0.1<=c<=0.5, 0.1<=c<=0.4, 0.1<=c<=0.3, 0.1<=c<=0.2, or 0.2<=c<0.5, and the general formula Li 1+x Ni a Mn b Co c Al (1-a-b-c) O2. In some embodiments, the cathode active material has the general formula LiMPO4, where M is selected from the group consisting of Fe, Co, Ni, Mn, Al, Mg, Zn, Ti, La, Ce, Sn, Zr, Ru, Si, Ge, and combinations thereof. In some embodiments, the cathode active material is selected from the group consisting of LiFePO4, LiCoPO4, LiNiPO4, LiMnPO4, LiMnFePO4, and combinations thereof. In some embodiments, the cathode active material is LiNi x Mn y O4, where 0.1<=x<=0.8, and 0.1<=y<=2.

[0160] In certain embodiments, the cathode active material is doped with a dopant selected from the group consisting of Fe, Ni, Mn, Al, Mg, Zn, Ti, La, Ce, Sn, Zr, Ru, Si, Ge, and combinations thereof. In some embodiments, the dopant is not Fe, Ni, Mn, Mg, Zn, Ti, La, Ce, Ru, Si, or Ge. In some embodiments, the dopant is not Al, Sn, or Zr.

[0161] In some embodiments, the cathode active material is LiNi 0.33 Mn 0.33 Co 0.33 O2(NMC333), LiNi 0.4 Mn 0.4 Co 0.2 O2, LiNi 0.5 Mn 0.3 Co 0.2 O2(NMC532), LiNi 0.6 Mn 0.2 Co 0.2 O2(NMC622), LiNi 0.7 Mn 0.15 Co 0.15 O2, LiNi 0.8 Mn 0.1 Co 0.1 O2(NMC811), LiNi 0.92 Mn 0.04 Co 0.04 O2, LiNi 0.8 Co 0.15 Al 0.05 O2(NCA), LiNiO2(LNO), or a combination thereof.

[0162] In other embodiments, the cathode active material is not LiCoO2, LiNiO2, LiMnO2, LiMn2O4, or Li2MnO3. In further embodiments, the cathode active material is LiNi 0.33 Mn 0.33 Co 0.33 O2, LiNi 0.4 Mn 0.4 Co 0.2 O2, LiNi 0.5 Mn 0.3 Co 0.2 O2, LiNi 0.6 Mn 0.2 Co 0.2 O2, LiNi 0.7 Mn 0.15 Co 0.15 O2, LiNi 0.8 Mn 0.1 Co 0.1 O2, LiNi 0.92 Mn 0.04 Co 0.04 O2, or LiNi0.8 Co 0.15 Al 0.05 Not O2.

[0163] In some embodiments, the cathode active material comprises or is a core-shell composite. A core-shell composite has a core structure and a shell structure, where each of the core and the shell is Li 1+x Ni a Mn b Co c Al (1-a-b-c) O2, LiCoO2, LiNiO2, LiMnO2, LiMn2O4, Li2MnO3, LiCrO2, Li4Ti5O 12 , LiV2O5, LiTiS2, LiMoS2, and combinations thereof, where -0.2<=x<=0.2, 0<=a<1, 0<=b<1, 0<=c<1, and a+b+c<=1. In other embodiments, the core and shell each independently comprise two or more lithium transition metal oxides. In some embodiments, one of the core or shell comprises only one lithium transition metal oxide, while the other comprises two or more lithium transition metal oxides. The lithium transition metal oxide or oxides in the core and shell may be the same, or they may be different or partially different. In some embodiments, the two or more lithium transition metal oxides are uniformly distributed on the core. In certain embodiments, the two or more lithium transition metal oxides are not uniformly distributed on the core. In some embodiments, the cathode active material is not a core-shell composite.

[0164] In some embodiments, each of the lithium transition metal oxides in the core and shell is independently doped with a dopant selected from the group consisting of Fe, Ni, Mn, Al, Mg, Zn, Ti, La, Ce, Sn, Zr, Ru, Si, Ge, and combinations thereof. In some embodiments, the core and shell each independently comprise two or more doped lithium transition metal oxides. In some embodiments, the two or more doped lithium transition metal oxides are uniformly distributed on the core and / or shell. In some embodiments, the two or more doped lithium transition metal oxides are not uniformly distributed on the core and / or shell.

[0165] In some embodiments, the cathode active material comprises or is a core-shell composite. The core-shell composite comprises a core comprising a lithium transition metal oxide and a shell comprising a transition metal oxide. In certain embodiments, the lithium transition metal oxide is Li 1+x Ni a Mn b Co c Al (1-a-b-c) O2, LiCoO2, LiNiO2, LiMnO2, LiMn2O4, Li2MnO3, LiCrO2, Li4Ti5O 12 , LiV2O5, LiTiS2, LiMoS2, and combinations thereof, where -0.2<=x<=0.2, 0<=a<1, 0<=b<1, 0<=c<1, and a+b+c<=1. In some embodiments, the transition metal oxide is selected from the group consisting of Fe2O3, MnO2, Al2O3, MgO, ZnO, TiO2, La2O3, CeO2, SnO2, ZrO2, RuO2, and combinations thereof. In certain embodiments, the shell comprises a lithium transition metal oxide and a transition metal oxide.

[0166] In some embodiments, the diameter of the core is from about 1 micron to about 15 microns, from about 3 microns to about 15 microns, from about 3 microns to about 10 microns, from about 5 microns to about 10 microns, from about 5 microns to about 45 microns, from about 5 microns to about 35 microns, from about 5 microns to about 25 microns, from about 10 microns to about 45 microns, from about 10 microns to about 40 microns, or from about 10 microns to about 35 microns, from about 10 microns to about 25 microns, from about 15 microns to about 45 microns, from about 15 microns to about 30 microns, from about 15 microns to about 25 microns, from about 20 microns to about 35 microns, or from about 20 microns to about 30 microns. In certain embodiments, the shell thickness is from about 1 micron to about 45 microns, from about 1 micron to about 35 microns, from about 1 micron to about 25 microns, from about 1 micron to about 15 microns, from about 1 micron to about 10 microns, from about 1 micron to about 5 microns, from about 3 microns to about 15 microns, from about 3 microns to about 10 microns, from about 5 microns to about 10 microns, from about 10 microns to about 35 microns, from about 10 microns to about 20 microns, from about 15 microns to about 30 microns, from about 15 microns to about 25 microns, or from about 20 microns to about 35 microns. In certain embodiments, the ratio of the diameter or thickness 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 certain embodiments, the volume or weight ratio of the core to the shell is 95:5, 90:10, 80:20, 70:30, 60:40, 50:50, 40:60, or 30:70.

[0167] In some embodiments, the percentage of cathode active material in the aqueous solvent-based cathode slurry is from about 20% to about 70%, from about 20% to about 65%, from about 20% to about 60%, from about 20% to about 55%, from about 20% to about 50%, from about 20% to about 40%, from about 20% to about 30%, from about 30% to about 70%, from about 30% to about 65%, from about 30% to about 60%, from about 30% to about 55%, from about 30% to about 50%, from about 40% to about 70%, from about 40% to about 65%, from about 40% to about 60%, from about 40% to about 55%, from about 40% to about 50%, from about 50% to about 70%, or from about 50% to about 60% by weight, based on the total weight of the aqueous solvent-based cathode slurry. In certain embodiments, the proportion of the cathode active material in the aqueous solvent-based cathode slurry is greater than 20%, greater than 30%, greater than 40%, greater than 50%, or greater than 60% by weight, based on the total weight of the aqueous solvent-based cathode slurry. In some embodiments, the proportion of the cathode active material in the aqueous solvent-based cathode slurry is less than 70%, less than 60%, less than 50%, less than 40%, or less than 30% by weight, based on the total weight of the aqueous solvent-based cathode slurry.

[0168] In some embodiments, the third suspension is stirred for a period of from about 10 minutes to about 120 minutes, from about 20 minutes to about 120 minutes, from about 30 minutes to about 120 minutes, from about 40 minutes to about 120 minutes, from about 50 minutes to about 120 minutes, from about 60 minutes to about 120 minutes, from about 60 minutes to about 110 minutes, from about 60 minutes to about 100 minutes, from about 60 minutes to about 90 minutes, from about 55 minutes to about 90 minutes, from about 50 minutes to about 90 minutes, from about 45 minutes to about 90 minutes, from about 45 minutes to about 85 minutes, from about 45 minutes to about 80 minutes, or from about 45 minutes to about 75 minutes to achieve uniform distribution of the cathode active material.

[0169] In certain embodiments, the third suspension is stirred for a period of less than 120 minutes, less than 110 minutes, less than 100 minutes, less than 90 minutes, less than 80 minutes, less than 70 minutes, less than 60 minutes, less than 55 minutes, less than 50 minutes, less than 45 minutes, less than 40 minutes, less than 35 minutes, less than 30 minutes, less than 25 minutes, less than 20 minutes, or less than 15 minutes to achieve uniform distribution of the cathode active material. In some embodiments, the third suspension is stirred for a period of more than 10 minutes, more than 15 minutes, more than 20 minutes, more than 25 minutes, more than 30 minutes, more than 35 minutes, more than 40 minutes, more than 45 minutes, more than 50 minutes, more than 55 minutes, more than 60 minutes, more than 65 minutes, more than 70 minutes, more than 75 minutes, more than 80 minutes, more than 85 minutes, more than 90 minutes, more than 100 minutes, or more than 110 minutes to achieve uniform distribution of the cathode active material.

[0170] In some embodiments, the third suspension is stirred at a speed of from about 500 rpm to about 1500 rpm, from about 550 rpm to about 1500 rpm, from about 600 rpm to about 1500 rpm, from about 650 rpm to about 1500 rpm, from about 700 rpm to about 1500 rpm, from about 750 rpm to about 1500 rpm, from about 800 rpm to about 1500 rpm, from about 850 rpm to about 1500 rpm, from about 900 rpm to about 1500 rpm, from about 950 rpm to about 1500 rpm, from about 1000 rpm to about 1500 rpm, from about 1000 rpm to about 1400 rpm, from about 1000 rpm to about 1300 rpm, or from about 1100 rpm to about 1300 rpm to achieve a uniform distribution of the cathode active material.

[0171] In some embodiments, the third suspension is stirred at a speed of less than 1500 rpm, less than 1400 rpm, less than 1300 rpm, less than 1200 rpm, less than 1100 rpm, less than 1000 rpm, less than 900 rpm, less than 800 rpm, less than 700 rpm, or less than 600 rpm to achieve uniform dispersion of the cathode active material. In some embodiments, the third suspension is stirred at a speed of greater than 500 rpm, greater than 600 rpm, greater than 700 rpm, greater than 800 rpm, greater than 900 rpm, greater than 1000 rpm, greater than 1100 rpm, greater than 1200 rpm, greater than 1300 rpm, or greater than 1400 rpm to achieve uniform dispersion of the cathode active material.

[0172] In other embodiments, a water-compatible copolymer binder (and conductive agent) can be dispersed in an aqueous solvent to form a first suspension. A second suspension can then be formed by dispersing the cathode active material in the first suspension. A third suspension can then be formed by adding a lithium compound to the second suspension.

[0173] In some embodiments, prior to homogenization of the third suspension, the third suspension is degassed under reduced pressure for a short period of time to remove any trapped air bubbles within the suspension. In some embodiments, the third suspension is degassed at a pressure of about 1 kPa to about 20 kPa, about 1 kPa to about 15 kPa, about 1 kPa to about 10 kPa, about 5 kPa to about 20 kPa, about 5 kPa to about 15 kPa, or about 10 kPa to about 20 kPa. In certain embodiments, the third suspension is degassed at a pressure of less than 20 kPa, less than 15 kPa, or less than 10 kPa.

[0174] In some embodiments, the third suspension is degassed for a period of about 30 minutes to about 4 hours, about 1 hour to about 4 hours, about 2 hours to about 4 hours, or about 30 minutes to about 2 hours, hi certain embodiments, the third suspension is degassed for a period of less than 4 hours, less than 2 hours, or less than 1 hour.

[0175] In some embodiments, the third suspension is degassed after homogenization. The homogenized third suspension may also be degassed at the pressure and for the period described in the procedure for degassing the third suspension before homogenization.

[0176] In some embodiments, the homogenized aqueous solvent-based cathode slurry is formed in step 104 by homogenizing the third suspension with a homogenizer.

[0177] The third suspension is homogenized in a homogenizer at a temperature of about 10°C to about 30°C to obtain a homogenized aqueous solvent-based cathode slurry. The homogenizer may be equipped with a temperature regulation system. The temperature of the third suspension may also be controlled by the temperature regulation system. Any homogenizer capable of reducing or eliminating particle agglomeration and / or promoting uniform distribution of the cathode slurry materials may be used herein. Uniform distribution plays an important role in producing batteries with good battery performance. In some embodiments, the homogenizer is a planetary steering mixer, a steering mixer, a blender, or an ultrasonic device.

[0178] In some embodiments, the third suspension is homogenized at a temperature of about 10° C. to about 30° C., about 10° C. to about 25° C., about 10° C. to about 20° C., or about 10° C. to about 15° C. In some embodiments, the third suspension is homogenized at a temperature below 30° C., below 25° C., below 20° C., or below 15° C.

[0179] In some embodiments, the planetary steering mixer includes at least one planetary blade and at least one high-speed dispersion blade. In some embodiments, the rotational speed of the planetary blade is from about 20 rpm to about 200 rpm, from about 20 rpm to about 150 rpm, from about 30 rpm to about 150 rpm, or from about 50 rpm to about 100 rpm. In some embodiments, the rotational speed of the dispersion blade is from about 1,000 rpm to about 4,000 rpm, from about 1,000 rpm to about 3,500 rpm, from about 1,000 rpm to about 3,000 rpm, from about 1,000 rpm to about 2,000 rpm, from about 1,500 rpm to about 3,000 rpm, or from about 1,500 rpm to about 2,500 rpm.

[0180] In certain embodiments, the ultrasonic device is an ultrasonic bath, a probe-type ultrasonic device, or an ultrasonic flow cell. In some embodiments, the ultrasonic device is operated at a power density of from about 10 W / L to about 100 W / L, from about 20 W / L to about 100 W / L, from about 30 W / L to about 100 W / L, from about 40 W / L to about 80 W / L, from about 40 W / L to about 70 W / L, from about 40 W / L to about 60 W / L, from about 40 W / L to about 50 W / L, from about 50 W / L to about 60 W / L, from about 20 W / L to about 80 W / L, from about 20 W / L to about 60 W / L, or from about 20 W / L to about 40 W / L. In certain embodiments, the ultrasound device is operated at a power density greater than 10 W / L, greater than 20 W / L, greater than 30 W / L, greater than 40 W / L, greater than 50 W / L, greater than 60 W / L, greater than 70 W / L, greater than 80 W / L, or greater than 90 W / L.

[0181] In some embodiments, the third suspension is homogenized for a period of about 10 minutes to about 6 hours, about 10 minutes to about 5 hours, about 10 minutes to about 4 hours, about 10 minutes to about 3 hours, about 10 minutes to about 2 hours, about 10 minutes to about 1 hour, about 10 minutes to about 30 minutes, about 30 minutes to about 3 hours, about 30 minutes to about 2 hours, about 30 minutes to about 1 hour, about 1 hour to about 6 hours, about 1 hour to about 5 hours, about 1 hour to about 4 hours, about 1 hour to about 3 hours, about 1 hour to about 2 hours, about 2 hours to about 6 hours, about 2 hours to about 4 hours, about 2 hours to about 3 hours, about 3 hours to about 5 hours, or about 4 hours to about 6 hours to promote uniformity of distribution of the cathode slurry material. In certain embodiments, the third suspension is homogenized for a period of less than 6 hours, less than 5 hours, less than 4 hours, less than 3 hours, less than 2 hours, less than 1 hour, or less than 30 minutes to promote uniformity of distribution of the cathode slurry material. In some embodiments, the third suspension is homogenized for a period of more than 10 minutes, more than 20 minutes, more than 30 minutes, more than 1 hour, more than 2 hours, more than 3 hours, more than 4 hours, or more than 5 hours to promote uniformity of distribution of the cathode slurry material.

[0182] In some embodiments, the pH of the aqueous solvent-based cathode slurry is from about 8 to about 14, from about 8 to about 13.5, from about 8 to about 13, from about 8 to about 12.5, from about 8 to about 12, from about 8 to about 11.5, from about 8 to about 11, from about 8 to about 10.5, from about 8 to about 10, from about 8 to about 9, from about 9 to about 14, from about 9 to about 13, from about 9 to about 12, from about 9 to about 11, from about 10 to about 14, The pH may be from 10 to about 13, from about 10 to about 12, from about 10 to about 11, from about 10.5 to about 14, from about 10.5 to about 13.5, from about 10.5 to about 13, from about 10.5 to about 12.5, from about 10.5 to about 12, from about 10.5 to about 11.5, from about 11 to about 14, from about 11 to about 13, from about 11 to about 12, from about 11.5 to about 12.5, from about 11.5 to about 12, or from about 12 to about 14. In certain embodiments, the pH of the aqueous solvent-based cathode slurry is less than 14, less than 13.5, less than 13, less than 12.5, less than 12, less than 11.5, less than 11, less than 10.5, less than 10, less than 9.5, less than 9, or less than 8.5. In some embodiments, the pH of the aqueous solvent-based cathode slurry is greater than 8, greater than 8.5, greater than 9, greater than 9.5, greater than 10, greater than 10.5, greater than 11, greater than 11.5, greater than 12, greater than 12.5, greater than 13, or greater than 13.5.

[0183] In some embodiments, the solids content of the aqueous solvent-based cathode slurry is from about 40% to about 80%, from about 45% to about 75%, from about 45% to about 70%, from about 45% to about 65%, from about 45% to about 60%, from about 45% to about 55%, from about 45% to about 50%, from about 50% to about 75%, from about 50% to about 70%, from about 50% to about 65%, from about 55% to about 75%, from about 55% to about 70%, from about 60% to about 75%, or from about 65% to about 75% by weight, based on the total weight of the aqueous solvent-based cathode slurry. In some embodiments, the solids content of the aqueous solvent-based cathode slurry is greater than 40%, greater than 45%, greater than 50%, greater than 55%, greater than 60%, greater than 70%, greater than 65%, greater than 70%, or greater than 75% by weight, based on the total weight of the aqueous solvent-based cathode slurry. In some embodiments, the solids content of the aqueous solvent-based cathode slurry is less than 80%, less than 75%, less than 70%, less than 65%, less than 60%, less than 55%, less than 50%, or less than 45% by weight, based on the total weight of the aqueous solvent-based cathode slurry.

[0184] The aqueous solvent-based cathode slurries of the present invention can have higher solids contents than conventional cathode slurries, which allows more cathode active material to be ready for further processing at any one time, thereby improving efficiency and maximizing productivity.

[0185] The viscosity of the aqueous solvent-based cathode slurry is preferably less than about 8,000 mPa·s. In some embodiments, the viscosity of the aqueous solvent-based cathode slurry is from about 1,000 mPa·s to about 8,000 mPa·s, from about 1,000 mPa·s to about 7,000 mPa·s, from about 1,000 mPa·s to about 6,000 mPa·s, from about 1,000 mPa·s to about 5,000 mPa·s, from about 1,000 mPa·s to about 4,000 mPa·s, from about 1,000 mPa·s to about 3,000 mPa·s, or from about 1,000 mPa·s to about 2,000 mPa·s. In certain embodiments, the viscosity of the aqueous solvent-based cathode slurry is less than 8,000 mPa·s, less than 7,000 mPa·s, less than 6,000 mPa·s, less than 5,000 mPa·s, less than 4,000 mPa·s, less than 3,000 mPa·s, or less than 2,000 mPa·s. In some embodiments, the viscosity of the aqueous solvent-based cathode slurry is greater than 1,000 mPa·s, greater than 2,000 mPa·s, greater than 3,000 mPa·s, greater than 4,000 mPa·s, greater than 5,000 mPa·s, greater than 6,000 mPa·s, or greater than 7,000 mPa·s. Thus, the composite slurry can be thoroughly mixed or homogenous.

[0186] The aqueous solvent-based cathode slurries disclosed herein have a small D50 and a uniform, narrow particle size distribution. In some embodiments, the aqueous solvent-based cathode slurries of the present invention have a particle size of about 0.1 micron to about 20 microns, about 0.2 micron to about 20 microns, about 0.3 micron to about 20 microns, about 0.4 micron to about 20 microns, about 0.5 micron to about 20 microns, about 0.1 micron to about 19.5 microns, about 0.2 micron to about 19.5 microns, about 0.3 micron to about 19.5 microns, about 0.4 micron to about 19 microns, or about 0.5 micron to about 20 microns. up to about 0.5 micrometers, from about 0.1 micrometers to about 19 micrometers, from about 0.2 micrometers to about 19 micrometers, from about 0.3 micrometers to about 19 micrometers, from about 0.4 micrometers to about 19 micrometers, from about 0.5 micrometers to about 19 micrometers, from about 0.1 micrometers to about 18.5 micrometers, from about 0.2 micrometers to about 18.5 micrometers, from about 0.3 micrometers to about 18.5 micrometers, from about 0.4 micrometers to about 18.5 micrometers, About 0.5 micrometers to about 18.5 micrometers, about 0.1 micrometers to about 18 micrometers, about 0.2 micrometers to about 18 micrometers, about 0.3 micrometers to about 18 micrometers, about 0.4 micrometers to about 18 micrometers, about 0.5 micrometers to about 18 micrometers, about 0.2 micrometers to about 17.5 micrometers, about 0.2 micrometers to about 17 micrometers, about 0.2 micrometers to about 16.5 micrometers, about 0.2 micrometers to about 16 micrometers, about 0.2 micrometers from about 0.2 microm to about 15.5 microm, from about 0.2 microm to about 15 microm, from about 0.2 microm to about 14.5 microm, from about 0.2 microm to about 14 microm, from about 0.2 microm to about 13.5 microm, from about 0.2 microm to about 13 microm, from about 0.2 microm to about 12.5 microm, from about 0.2 microm to about 12 microm, from about 0.2 microm to about 11.5 microm, from about 0.2 microm to about 11 microm, from about 0.2 microm to about 10.The particle size D50 ranges from about 5 microns, from about 0.2 microns to about 10 microns, from about 0.4 microns to about 17 microns, from about 0.5 microns to about 17 microns, from about 1 micron to about 16 microns, or from about 1 micron to about 15 microns.

[0187] In certain embodiments, the particle size D50 of the aqueous solvent-based cathode slurry is less than 20 microns, less than 18 microns, less than 16 microns, less than 14 microns, less than 12 microns, less than 10 microns, less than 8 microns, less than 6 microns, less than 4 microns, less than 2 microns, or less than 1 micron. In some embodiments, the particle size D50 of the aqueous solvent-based cathode slurry is greater than 1 micron, greater than 2 microns, greater than 4 microns, greater than 6 microns, greater than 8 microns, greater than 10 microns, greater than 12 microns, greater than 14 microns, greater than 16 microns, or greater than 18 microns.

[0188] In some embodiments, the particle size D10 of the aqueous solvent-based cathode slurry is from about 0.05 micrometers to about 8 micrometers, from about 0.1 micrometers to about 8 micrometers, from about 0.15 micrometers to about 8 micrometers, from about 0.2 micrometers to about 8 micrometers, from about 0.25 micrometers to about 8 micrometers, from about 0.3 micrometers to about 8 micrometers, from about 0.35 micrometers to about 8 micrometers, from about 0.4 micrometers to about 8 micrometers, or from about 0.1 micrometers to about 7.5 micrometers. , about 0.15 micrometers to about 7.5 micrometers, about 0.2 micrometers to about 7.5 micrometers, about 0.25 micrometers to about 7.5 micrometers, about 0.3 micrometers to about 7.5 micrometers, about 0.35 micrometers to about 7.5 micrometers, about 0.4 micrometers to about 7.5 micrometers, about 0.1 micrometers to about 7 micrometers, about 0.15 micrometers to about 7 micrometers, about 0.2 micrometers to about 7 micrometers, about 0.25 micrometers to about 7 micrometers, about 0.3 micrometers to about 7 micrometers, about 0.35 micrometers to about 7 micrometers, about 0.4 micrometers to about 7 micrometers, about 0.1 micrometers to about 6.5 micrometers, about 0.15 micrometers to about 6.5 micrometers, about 0.2 micrometers to about 6.5 micrometers, about 0.25 micrometers to about 6.5 micrometers, about 0.3 micrometers to about 6.5 micrometers, about 0.35 micrometers to about 6.5 micrometers, about 0.4 micrometers to about 6.5 micrometers, about 0.1 micrometers micrometer to about 6 micrometers, about 0.15 micrometers to about 6 micrometers, about 0.2 micrometers to about 6 micrometers, about 0.25 micrometers to about 6 micrometers, about 0.3 micrometers to about 6 micrometers, about 0.35 micrometers to about 6 micrometers, about 0.4 micrometers to about 6 micrometers, about 0.2 micrometers to about 5 micrometers, about 0.2 micrometers to about 4 micrometers, about 0.3 micrometers to about 5 micrometers, or about 0.3 micrometers to about 4 micrometers.

[0189] In some embodiments, the particle size D10 of the aqueous solvent-based cathode slurry is less than 8 microns, less than 7 microns, less than 6 microns, less than 5 microns, less than 4 microns, less than 3 microns, less than 2 microns, less than 1 micron, less than 0.5 microns, or less than 0.1 microns. In some embodiments, the particle size D10 of the aqueous solvent-based cathode slurry is greater than 0.05 microns, greater than 0.1 microns, greater than 0.5 microns, greater than 1 micron, greater than 2 microns, greater than 3 microns, greater than 4 microns, greater than 5 microns, greater than 6 microns, or greater than 7 microns.

[0190] In some embodiments, the particle size D90 of the aqueous solvent-based cathode slurry is from about 0.5 microns to about 40 microns, from about 0.5 microns to about 39 microns, from about 0.5 microns to about 38 microns, from about 0.5 microns to about 37 microns, from about 0.5 microns to about 35 microns, from about 0.5 microns to about 34 microns, from about 1 micron to about 40 microns, from about 1 micron to about 39 microns, from about 1 micron to about 3 Up to 9 microns, about 1 micron to about 38 microns, about 1 micron to about 37 microns, about 1 micron to about 36 microns, about 1 micron to about 35 microns, about 1 micron to about 34 microns, about 1.5 microns to about 40 microns, about 1.5 microns to about 39 microns, about 1.5 microns to about 38 microns, about 1.5 microns to about 37 microns, about 1.5 microns to about 36 microns, about 1.5 micrometers to about 35 micrometers, about 1.5 micrometers to about 34 micrometers, about 2 micrometers to about 40 micrometers, about 2 micrometers to about 39 micrometers, about 2 micrometers to about 38 micrometers, about 2 micrometers to about 37 micrometers, about 2 micrometers to about 36 micrometers, about 2 micrometers to about 35 micrometers, about 2 micrometers to about 34 micrometers, about 1 micrometer to about 33 micrometers, about 1 micrometer to about 32 micrometers, about 1 micrometer to about 35 micrometers micrometer to about 30 micrometers, about 1 micrometer to about 28 micrometers, about 1 micrometer to about 26 micrometers, about 1 micrometer to about 24 micrometers, about 1 micrometer to about 22 micrometers, about 1 micrometer to about 20 micrometers, about 2 micrometers to about 33 micrometers, 2 micrometers to about 30 micrometers, about 2 micrometers to about 26 micrometers, about 2 micrometers to about 20 micrometers, or about 2 micrometers to about 15 micrometers.

[0191] In some embodiments, the particle size D90 of the aqueous solvent-based cathode slurry is less than 40 microns, less than 38 microns, less than 36 microns, less than 34 microns, less than 32 microns, less than 30 microns, less than 28 microns, less than 26 microns, less than 24 microns, less than 22 microns, less than 20 microns, less than 18 microns, less than 16 microns, less than 14 microns, less than 12 microns, less than 10 microns, less than 8 microns, less than 6 microns, or less than 4 microns. In some embodiments, the particle size D90 of the aqueous solvent-based cathode slurry is greater than 0.5 microns, greater than 1 micron, greater than 2 microns, greater than 4 microns, greater than 6 microns, greater than 8 microns, greater than 10 microns, greater than 12 microns, greater than 14 microns, greater than 16 microns, greater than 18 microns, greater than 20 microns, greater than 22 microns, greater than 24 microns, greater than 26 microns, greater than 28 microns, greater than 30 microns, greater than 32 microns, greater than 34 microns, greater than 36 microns, or greater than 38 microns.

[0192] In some embodiments, the ratio of particle size D90 to particle size D10 of the aqueous solvent-based cathode slurry is from about 2 to about 10, from about 2.5 to about 10, from about 3 to about 10, from about 3.5 to about 10, from about 4 to about 10, from about 4.5 to about 10, from about 5 to about 10, from about 2 to about 9.5, from about 2.5 to about 9.5, from about 3 to about 9.5, from about 3.5 to about 9.5, from about 4 to about 9.5, from about 4.5 to about 9.5, from about 5 to about 9.5, from about 2 to about 9.5 and about 2.5 to about 9, about 3 to about 9, about 3.5 to about 9, about 4 to about 9, about 4.5 to about 9, about 5 to about 9, about 2 to about 8.5, about 2.5 to about 8.5, about 3 to about 8.5, about 3.5 to about 8.5, about 4 to about 8.5, about 4.5 to about 8.5, about 5 to about 8.5, about 2 to about 8, about 2 to about 7, about 2 to about 6.5, about 2 to about 6, about 3 to about 8, about 3 to about 7, or about 3 to about 6.

[0193] In some embodiments, the ratio of particle size D90 to particle size D10 of the aqueous solvent-based cathode slurry is less than 10, less than 9.5, less than 9, less than 8.5, less than 8, less than 7.5, less than 7, less than 6.5, less than 6, less than 5.5, less than 5, less than 4.5, less than 4, less than 3.5, less than 3, or less than 2.5. In some embodiments, the ratio of particle size D90 to particle size D10 of the aqueous solvent-based cathode slurry is greater than 2, greater than 2.5, greater than 3, greater than 3.5, greater than 4, greater than 4.5, greater than 5, greater than 5.5, greater than 6, greater than 6.5, greater than 7, greater than 7.5, greater than 8, greater than 8.5, greater than 9, or greater than 9.5.

[0194] In conventional methods for preparing cathode slurries, dispersants may be used to help disperse the cathode active material, conductive agent, and binder material in the slurry solvent. In some embodiments, the dispersant is a nonionic surfactant, an anionic surfactant, a cationic surfactant, an amphoteric surfactant, or a combination thereof. One of the advantages of the present invention is that the cathode slurry materials are homogeneously dispersed at room temperature without the use of a dispersant. This is beneficial because the presence of a dispersant in the cathode layer can cause deterioration of electrochemical performance. Furthermore, surfactants can be harmful to the environment when released, and many surfactants are toxic.

[0195] In some embodiments, the method does not include the step of adding a dispersant to the first suspension, the second suspension, the third suspension, or the homogenized aqueous solvent-based cathode slurry. In certain embodiments, each of the first suspension, the second suspension, the third suspension, and the homogenized aqueous solvent-based cathode slurry is independently dispersant-free. In some embodiments, the method does not include the step of adding a nonionic surfactant, an anionic surfactant, a cationic surfactant, an amphoteric surfactant, or a combination thereof to the first suspension, the second suspension, the third suspension, or the homogenized aqueous solvent-based cathode slurry. In certain embodiments, each of the first suspension, the second suspension, the third suspension, and the homogenized aqueous solvent-based cathode slurry is independently free of a nonionic surfactant, an anionic surfactant, a cationic surfactant, and an amphoteric surfactant.

[0196] In some embodiments, fatty acid salts, alkyl sulfates, polyoxyalkylene alkyl ether acetates, alkylbenzene sulfonates, polyoxyalkylene alkyl ether sulfates, higher fatty acid amidosulfonates, N-acyl sarcosinates, alkyl phosphates, polyoxyalkylene alkyl ether phosphates, long chain sulfosuccinates, long chain N-acyl glutamates, polymers and copolymers comprising acrylic acid, anhydrides, esters, vinyl monomers and / or olefins and their alkali metal, alkaline earth metal and / or ammonium salt derivatives, salts of polycarboxylic acids, formalin condensates of naphthalene sulfonic acid, alkyl naphthalene sulfonates. Anionic surfactants, including naphthalene sulfonates such as sulfonic acid, naphthalene sulfonic acid, alkyl naphthalene sulfonates, their alkali metal salts, alkaline earth metal salts, ammonium salts, or amine salts, and formalin condensates of the acids, melamine sulfonic acid, alkyl melamine sulfonic acids, formalin condensates of melamine sulfonic acids, formalin condensates of alkyl melamine sulfonic acids, alkali metal salts, alkaline earth metal salts, ammonium salts, and amine salts of melamine sulfonic acid, lignin sulfonic acid, and alkali metal salts, alkaline earth metal salts, ammonium salts, and amine salts of lignin sulfonic acid, are not added to the aqueous solvent-based cathode slurry.

[0197] In some embodiments, cationic surfactants, including alkyltrimethylammonium salts such as stearyltrimethylammonium chloride, lauryltrimethylammonium chloride, and cetyltrimethylammonium bromide, dialkyldimethylammonium salts, trialkylmethylammonium salts, tetraalkylammonium salts, alkylamine salts, benzalkonium salts, alkylpyridinium salts, and imidazolium salts, are not added to the aqueous solvent-based cathode slurry.

[0198] In some embodiments, nonionic surfactants including polyoxyalkylene oxide-added alkyl ethers, polyoxyalkylene styrene phenyl ethers, polyhydric alcohols, ester compounds of monohydric fatty acids, polyoxyalkylene alkyl phenyl ethers, polyoxyalkylene fatty acid ethers, polyoxyalkylene sorbitan fatty acid esters, glycerin fatty acid esters, polyoxyalkylene castor oil, polyoxyalkylene hydrogenated castor oil, polyoxyalkylene sorbitol fatty acid esters, polyglycerin fatty acid esters, alkyl glycerin ethers, polyoxyalkylene cholesteryl ethers, alkyl polyglucosides, sucrose fatty acid esters, polyoxyalkylene alkylamines, polyoxyethylene-polyoxypropylene block polymers, sorbitan fatty acid esters, and fatty acid alkanolamides are not added to the aqueous solvent-based cathode slurry.

[0199] In some embodiments, amphoteric surfactants, including 2-undecyl-N,N-(hydroxyethylcarboxymethyl)-2-imidazoline sodium salt, 2-cocoyl-2-imidazolinium hydroxide-1-carboxyethyloxy disodium salt, imidazoline-based amphoteric surfactants, 2-heptadecyl-N-carboxymethyl-N-hydroxyethylimidazolium betaine, lauryl dimethyl amino acetoacetate betaine, alkyl betaines, amido betaines, sulfobetaines, and other betaine-based amphoteric surfactants, N-lauryl glycine, N-lauryl β-alanine, N-stearyl β-alanine, lauryl dimethyl amino oxide, oleyl dimethyl amino oxide, sodium lauroyl glutamate, lauryl dimethyl amino acetic acid betaine, stearyl dimethyl amino acetic acid betaine, cocamidopropyl hydroxysultaine, and 2-alkyl-N-carboxymethyl-N-hydroxyethyl imidazolinium betaine, are not added to the aqueous solvent-based cathode slurry.

[0200] In some embodiments, after uniform mixing of the cathode slurry materials, the homogenized aqueous solvent-based cathode slurry may be applied to a current collector to form a coating film on the current collector in step 105. The current collector serves to collect electrons generated by the electrochemical reaction of the cathode active material or to provide electrons required for the electrochemical reaction.

[0201] In some embodiments, the current collector can 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 an electrically conductive resin. In some embodiments, the current collector has a two-layer structure including an outer layer and an inner layer. Here, the outer layer includes a conductive material, and the inner layer includes an insulating material or another conductive material. For example, aluminum mounted with a conductive resin layer, or a polymeric insulating material covered with an aluminum film. In some embodiments, the current collector has a three-layer structure including an outer layer, a middle layer, and an inner layer. Here, the outer and inner layers include a conductive material, and the middle layer includes an insulating material or another conductive material. For example, it is a plastic substrate covered on both sides with a metal film. In some embodiments, the outer layer, middle layer, and inner layer are each independently stainless steel, titanium, nickel, aluminum, copper, or an alloy thereof, or an electrically conductive resin. In some embodiments, the insulating material is a polymeric material selected from the group consisting of polycarbonate, polyacrylate, polyacrylonitrile, polyester, polyamide, polystyrene, polyurethane, polyepoxy, poly(acrylonitrile butadiene styrene), polyimide, polyolefin, polyethylene, polypropylene, polyphenylene sulfide, poly(vinyl ester), polyvinyl chloride, polyether, polyphenylene oxide, cellulose polymer, and combinations thereof. In some embodiments, the current collector has more than three layers. In some embodiments, the current collector is coated with a corrosion-resistant coating. In some embodiments, the corrosion-resistant coating includes a carbon-containing material. In some embodiments, the current collector is coated with a corrosion-resistant coating.

[0202] In some embodiments, the conductive layer can be coated on an aluminum current collector to improve its current conductivity. In certain embodiments, the conductive layer comprises a material selected from the group consisting of carbon, carbon black, graphite, expanded graphite, graphene, graphene nanoplatelets, carbon fiber, carbon nanofiber, graphitized carbon flakes, carbon tubes, carbon nanotubes, activated carbon, Super P, zero-dimensional KS6, one-dimensional vapor-grown carbon fiber (VGCF), mesoporous carbon, and combinations thereof. In some embodiments, the conductive layer does not comprise carbon, carbon black, graphite, expanded graphite, graphene, graphene nanoplatelets, carbon fiber, carbon nanofiber, graphitized carbon flakes, carbon tubes, carbon nanotubes, activated carbon, Super P, zero-dimensional KS6, one-dimensional vapor-grown carbon fiber (VGCF), or mesoporous carbon.

[0203] In some embodiments, the conductive layer has a thickness of from about 0.5 microns to about 5.0 microns. The thickness of the conductive layer affects the volume occupied by the current collector in the battery, the amount of electrode material, and the capacity of the battery.

[0204] In certain embodiments, the thickness of the conductive layer on the current collector is from about 0.5 micrometers to about 4.5 micrometers, from about 1.0 micrometers to about 4.0 micrometers, from about 1.0 micrometers to about 3.5 micrometers, from about 1.0 micrometers to about 3.0 micrometers, from about 1.0 micrometers to about 2.5 micrometers, from about 1.0 micrometers to about 2.0 micrometers, from about 1.1 micrometers to about 2.0 micrometers, from about 1.2 micrometers to about 2.0 micrometers, from about 1.5 micrometers to about 2.0 micrometers, from about 1.8 micrometers to about 2.0 micrometers, from about 1.0 micrometers to about 1.8 micrometers, from about 1.2 micrometers to about 1.8 micrometers, from about 1.5 micrometers to about 1.8 micrometers, from about 1.0 micrometers to about 1.5 micrometers, or from about 1.2 micrometers to about 1.5 micrometers. In some embodiments, the thickness of the conductive layer on the current collector is less than 4.5 microns, less than 4.0 microns, less than 3.5 microns, less than 3.0 microns, less than 2.5 microns, less than 2.0 microns, less than 1.8 microns, less than 1.5 microns, or less than 1.2 microns. In some embodiments, the thickness of the conductive layer on the current collector is greater than 1.0 microns, greater than 1.2 microns, greater than 1.5 microns, greater than 1.8 microns, greater than 2.0 microns, greater than 2.5 microns, greater than 3.0 microns, or greater than 3.5 microns.

[0205] The thickness of the current collector affects the volume it occupies in the battery, the amount of electrode active material required, and the capacity of the battery. In some embodiments, the current collector has a thickness of about 5 microns to about 30 microns. In certain embodiments, the current collector has a thickness of about 5 microns to about 20 microns, about 5 microns to about 15 microns, about 10 microns to about 30 microns, about 10 microns to about 25 microns, or about 10 microns to about 20 microns.

[0206] In some embodiments, the coating process is carried out using a doctor blade coater, a slot die coater, a transfer coater, a spray coater, a roll coater, a gravure coater, a dip coater, or a curtain coater.

[0207] Evaporating the solvent is required to create a dry porous electrode, which in turn is needed to create a battery. In some embodiments, the cathode is formed by drying the coating film on a current collector in step 106.

[0208] Any dryer capable of drying the coating film on the current collector can be used herein. Some non-limiting examples of dryers include batch drying chambers, conveyor drying chambers, and microwave drying chambers. Some non-limiting examples of conveyor drying chambers include conveyor hot air drying chambers, conveyor resistance drying chambers, conveyor induction drying chambers, and conveyor microwave drying chambers.

[0209] In some embodiments, a conveyor drying chamber for drying a coating film on a current collector includes one or more heating sections, each of which is independently temperature controlled, and each of which may include an independently controlled heating zone.

[0210] In one embodiment, the conveyor drying chamber includes a first heating section located on one side of the conveyor and another heating section located on an opposite side of the conveyor from the first heating section, wherein each of the first and second heating sections independently includes one or more heating elements and a temperature regulation system connected to the heating elements of the first and second heating sections in a manner that monitors and selectively controls the temperature of each heating section.

[0211] In some embodiments, the conveyor drying chamber includes multiple heating sections, where each heating section includes an independent heating element that is operated to maintain a constant temperature within the heating section.

[0212] In one embodiment, each of the first and second heating sections has an independent inlet heating zone and an independent outlet heating zone, wherein each of the inlet and outlet heating zones independently includes one or more heating elements and a temperature regulation system connected to the heating elements of the inlet and outlet heating zones in a manner that monitors and selectively controls the temperature of each heating zone separately from the temperature control of the other heating zones.

[0213] The coating film on the current collector should be dried for approximately 20 minutes or less at a temperature of approximately 90° C. or less. Drying the coated cathode at a temperature higher than 90° C. may result in undesired deformation of the cathode, thereby affecting the performance of the cathode.

[0214] In some embodiments, the coating film on the current collector may be dried at a temperature of from about 25° C. to about 90° C. In certain embodiments, the coating film on the current collector may be dried at a temperature of from about 25° C. to about 80° C., from about 25° C. to about 70° C., from about 25° C. to about 60° C., from about 35° C. to about 90° C., from about 35° C. to about 80° C., from about 35° C. to about 75° C., from about 40° C. to about 90° C., from about 40° C. to about 80° C., or from about 40° C. to about 75° C. In some embodiments, the coating film on the current collector may be dried at a temperature of less than 90° C., less than 85° C., less than 80° C., less than 75° C., less than 70° C., less than 65° C., less than 60° C., less than 55° C., or less than 50° C. In some embodiments, the coating film on the current collector can be dried at a temperature greater than 25°C, greater than 30°C, greater than 35°C, greater than 40°C, greater than 45°C, greater than 50°C, greater than 55°C, greater than 60°C, greater than 65°C, greater than 70°C, greater than 75°C, greater than 80°C, or greater than 85°C.

[0215] In certain embodiments, the conveyor may have a speed of from about 1 meter / minute to about 120 meters / minute, from about 1 meter / minute to about 100 meters / minute, from about 1 meter / minute to about 80 meters / minute, from about 1 meter / minute to about 60 meters / minute, from about 1 meter / minute to about 40 meters / minute, from about 10 meters / minute to about 120 meters / minute, from about 10 meters / minute to about 80 meters / minute, from about 10 meters / minute to about 60 meters / minute, from about 10 meters / minute to about 40 meters / minute, from about 25 meters / minute to about 120 meters / minute, from about 25 meters / minute to about 10 meters / minute 0 meters / minute, from about 25 meters / minute to about 80 meters / minute, from about 25 meters / minute to about 60 meters / minute, from about 50 meters / minute to about 120 meters / minute, from about 50 meters / minute to about 100 meters / minute, from about 50 meters / minute to about 80 meters / minute, from about 75 meters / minute to about 120 meters / minute, from about 75 meters / minute to about 100 meters / minute, from about 2 meters / minute to about 25 meters / minute, from about 2 meters / minute to about 20 meters / minute, from about 3 meters / minute to about 30 meters / minute, or from about 3 meters / minute to about 20 meters / minute.

[0216] Controlling the conveyor length and speed can regulate the drying time of the coating film. In some embodiments, the coating film on the current collector can dry for a period of about 1 minute to about 30 minutes, about 1 minute to about 25 minutes, about 2 minutes to about 20 minutes, about 2 minutes to about 15 minutes, about 2 minutes to about 10 minutes, about 5 minutes to about 30 minutes, about 5 minutes to about 20 minutes, about 5 minutes to about 10 minutes, about 10 minutes to about 30 minutes, or about 10 minutes to about 20 minutes. In some embodiments, the coating film on the current collector can dry for a period of less than 30 minutes, less than 25 minutes, less than 20 minutes, less than 15 minutes, less than 10 minutes, or less than 5 minutes. In some embodiments, the coating film on the current collector can dry for a period of more than 1 minute, more than 5 minutes, more than 10 minutes, more than 15 minutes, more than 20 minutes, or more than 25 minutes.

[0217] After the coating film on the current collector is dried, the cathode is formed. In some embodiments, the cathode is compressed to increase the density of the cathode. In some embodiments, the dried and compressed coating film on the current collector is designated as an electrode layer.

[0218] In some embodiments, the proportion of the lithium compound in the cathode electrode layer is from about 0.01% to about 10%, from about 0.025% to about 10%, from about 0.05% to about 10%, from about 0.075% to about 10%, from about 0.1% to about 10%, from about 0.25% to about 10%, from about 0.5% to about 10%, from about 0.75% to about 10%, from about 0.75% to about 8%, from about 0.75% to about 6%, from about 0.75% to about 4%, from about 0.75% to about 3%, from about 0.75% to about 2%, from about 0.75% to about 1.5%, or from about 0.75% to about 1% by weight, based on the total weight of the electrode layer.

[0219] In some embodiments, the proportion of the lithium compound in the cathode electrode layer is less than 10%, less than 8%, less than 6%, less than 4%, less than 3%, less than 2%, less than 1.5%, less than 1%, less than 0.75%, less than 0.5%, less than 0.25%, less than 0.1%, less than 0.08%, or less than 0.05% by weight, based on the total weight of the electrode layer. In some embodiments, the proportion of the lithium compound in the cathode electrode layer is greater than 0.01%, greater than 0.025%, greater than 0.05%, greater than 0.075%, greater than 0.1%, greater than 0.25%, greater than 0.5%, greater than 0.75%, greater than 1%, greater than 1.5%, greater than 2%, greater than 3%, greater than 4%, or greater than 6% by weight, based on the total weight of the electrode layer.

[0220] In some embodiments, the proportion of binder material in the cathode electrode layer is from about 0.125% to about 25%, from about 0.25% to about 25%, from about 0.375% to about 25%, from about 0.5% to about 25%, from about 1% to about 25%, from about 1.5% to about 25%, from about 2% to about 25%, from about 4% to about 25%, from about 4% to about 22.5%, from about 4% to about 20%, from about 4% to about 17.5%, from about 4% to about 15%, from about 4% to about 12.5%, from about 4% to about 10%, or from about 4% to about 8% by weight, based on the total weight of the electrode layer.

[0221] In some embodiments, the percentage of binder material in the cathode electrode layer is less than 25%, less than 22.5%, less than 20%, less than 17.5%, less than 15%, less than 12.5%, less than 10%, less than 8%, less than 6%, less than 4%, less than 2%, less than 1.5%, or less than 1% by weight, based on the total weight of the electrode layer. In some embodiments, the percentage of binder material in the cathode electrode layer is greater than 0.125%, greater than 0.25%, greater than 0.375%, greater than 0.5%, greater than 1%, greater than 1.5%, greater than 2%, greater than 4%, greater than 6%, greater than 8%, greater than 10%, greater than 12.5%, or greater than 15% by weight, based on the total weight of the electrode layer.

[0222] In some embodiments, the proportion of the conductive agent in the cathode electrode layer is from about 0.625% to about 12.5%, from about 0.75% to about 12.5%, from about 0.875% to about 12.5%, from about 1% to about 12.5%, from about 1.5% to about 12.5%, from about 2% to about 12.5%, from about 2.5% to about 12.5%, from about 3% to about 12.5%, from about 3.5% to about 12.5%, from about 3.5% to about 10%, from about 3.5% to about 9%, from about 3.5% to about 8%, from about 3.5% to about 7%, from about 3.5% to about 6%, from about 3.5% to about 5.5%, from about 3.5% to about 5%, or from about 3.5% to about 4.5% by weight, based on the total weight of the electrode layer.

[0223] In some embodiments, the proportion of the conductive agent in the cathode electrode layer is less than 12.5%, less than 10%, less than 9%, less than 8%, less than 7%, less than 6%, less than 5.5%, less than 5%, less than 4.5%, less than 4%, less than 3.5%, less than 3%, less than 2.5%, less than 2%, less than 1.5%, or less than 1% by weight, based on the total weight of the electrode layer. In some embodiments, the proportion of the conductive agent in the cathode electrode layer is greater than 0.625%, greater than 0.75%, greater than 0.875%, greater than 1%, greater than 1.5%, greater than 2%, greater than 2.5%, greater than 3%, greater than 3.5%, greater than 4%, greater than 4.5%, greater than 5%, greater than 5.5%, greater than 7%, or greater than 8% by weight, based on the total weight of the electrode layer.

[0224] In some embodiments, the percentage of cathode active material in the electrode layer of the cathode is from about 50% to about 99%, from about 52.5% to about 99%, from about 55% to about 99%, from about 57.5% to about 99%, from about 60% to about 99%, from about 62.5% to about 99%, from about 65% to about 99%, from about 67.5% to about 99%, from about 70% to about 99%, from about 70% to about 97.5%, from about 70% to about 95%, from about 70% to about 92.5%, from about 70% to about 90%, from about 70% to about 87.5%, from about 70% to about 85%, from about 70% to about 82.5%, or from about 70% to about 80% by weight, based on the total weight of the electrode layer.

[0225] In some embodiments, the percentage of cathode active material in the electrode layer of the cathode is less than 99%, less than 97.5%, less than 95%, less than 92.5%, less than 90%, less than 87.5%, less than 85%, less than 82.5%, less than 80%, less than 77.5%, less than 75%, less than 72.5%, less than 70%, less than 67.5%, less than 65%, less than 62.5%, less than 60%, less than 57.5%, or less than 55% by weight, based on the total weight of the electrode layer. In some embodiments, the percentage of cathode active material in the electrode layer of the cathode is greater than 50%, greater than 52.5%, greater than 55%, greater than 57.5%, greater than 60%, greater than 62.5%, greater than 65%, greater than 67.5%, greater than 70%, greater than 72.5%, greater than 75%, greater than 77.5%, greater than 80%, greater than 82.5%, greater than 85%, greater than 87.5%, greater than 90%, greater than 92.5%, or greater than 95% by weight, based on the total weight of the electrode layer.

[0226] In certain embodiments, the thickness of each of the cathode and anode electrode layers on the current collector is independently from about 5 microns to about 90 microns, from about 5 microns to about 50 microns, from about 5 microns to about 25 microns, from about 10 microns to about 90 microns, from about 10 microns to about 50 microns, from about 10 microns to about 30 microns, from about 15 microns to about 90 microns, from about 20 microns to about 90 microns, from about 25 microns to about 90 microns, about 25 microns to about 80 microns, about 25 microns to about 75 microns, about 25 microns to about 50 microns, about 30 microns to about 90 microns, about 30 microns to about 80 microns, about 35 microns to about 90 microns, about 35 microns to about 85 microns, about 35 microns to about 80 microns, or about 35 microns to about 75 microns.

[0227] In some embodiments, the thickness of each of the cathode and anode electrode layers on the current collector is independently greater than 5 microns, greater than 10 microns, greater than 15 microns, greater than 20 microns, greater than 25 microns, greater than 30 microns, greater than 35 microns, greater than 40 microns, greater than 45 microns, greater than 50 microns, greater than 55 microns, greater than 60 microns, greater than 65 microns, greater than 70 microns, greater than 75 microns, or greater than 80 microns. In some embodiments, the thickness of each of the cathode and anode electrode layers on the current collector is independently less than 90 microns, less than 85 microns, less than 80 microns, less than 75 microns, less than 70 microns, less than 65 microns, less than 60 microns, less than 55 microns, less than 50 microns, less than 45 microns, less than 40 microns, less than 35 microns, less than 30 microns, less than 25 microns, less than 20 microns, less than 15 microns, or less than 10 microns.

[0228] In some embodiments, the areal density of each of the cathode and anode electrode layers on the current collector is independently about 1 mg / cm 2 to approximately 40 mg / cm 2 up to approximately 1 mg / cm 2 to approximately 35 mg / cm 2 up to approximately 1 mg / cm 2 to approximately 30 mg / cm 2 up to approximately 1 mg / cm 2 to approximately 25 mg / cm 2 up to approximately 1 mg / cm 2 to approximately 15 mg / cm 2 up to approximately 3 mg / cm 2 to approximately 40 mg / cm 2 up to approximately 3 mg / cm 2 to approximately 35 mg / cm 2 up to approximately 3 mg / cm 2 to approximately 30 mg / cm 2 up to approximately 3 mg / cm 2 to approximately 25 mg / cm 2 up to approximately 3 mg / cm 2 to approximately 20 mg / cm 2 up to approximately 3 mg / cm 2 to approximately 15 mg / cm 2 up to approximately 5 mg / cm 2 to approximately 40 mg / cm 2 up to approximately 5 mg / cm 2 to approximately 35 mg / cm 2 up to approximately 5 mg / cm 2 to approximately 30 mg / cm 2 up to approximately 5 mg / cm 2 to approximately 25 mg / cm 2 up to approximately 5 mg / cm 2 to approximately 20 mg / cm 2 up to approximately 5 mg / cm 2 to approximately 15 mg / cm 2 Up to approximately 8 mg / cm 2 to approximately 40 mg / cm 2 Up to approximately 8 mg / cm 2 to approximately 35 mg / cm 2 Up to approximately 8 mg / cm 2 to approximately 30 mg / cm 2 Up to approximately 8 mg / cm2 to approximately 25 mg / cm 2 Up to approximately 8 mg / cm 2 to approximately 20 mg / cm 2 up to approximately 10 mg / cm 2 to approximately 40 mg / cm 2 From about 10 mg / cm² to about 35 mg / cm² 2 up to approximately 10 mg / cm 2 to approximately 30 mg / cm 2 up to approximately 10 mg / cm 2 to approximately 25 mg / cm 2 up to approximately 10 mg / cm 2 to approximately 20 mg / cm 2 up to approximately 15 mg / cm 2 to approximately 40 mg / cm 2 up to, or about 20 mg / cm 2 to approximately 40 mg / cm 2 That's it.

[0229] In some embodiments, the areal density of each of the cathode and anode electrode layers on the current collector is independently 40 mg / cm 2 Less than 36 mg / cm 2 Less than 32 mg / cm 2 Less than 28 mg / cm 2 Less than 24 mg / cm 2 Less than 20 mg / cm 2 Less than 16 mg / cm 2 Less than 12 mg / cm 2 Less than 8 mg / cm 2 Less than or equal to 4 mg / cm 2 In some embodiments, the areal density of each of the cathode and anode electrode layers on the current collector is independently less than 1 mg / cm 2 greater than 4 mg / cm 2 Larger, 8 mg / cm 2 greater than 12 mg / cm 2 Larger, 16 mg / cm 2 Greater than 20 mg / cm 2 Larger, 24 mg / cm 2 Larger, 28 mg / cm 2 Larger, 32 mg / cm2 greater than or equal to 36 mg / cm 2 Greater than.

[0230] In some embodiments, the density of each of the cathode and anode electrode layers on the current collector is independently about 0.5 mg / cm 3 to approximately 6.5 mg / cm 3 up to approximately 0.5 mg / cm 3 to approximately 6.0 mg / cm 3 up to approximately 0.5 mg / cm 3 to approximately 5.5 mg / cm 3 up to approximately 0.5 mg / cm 3 to approximately 5.0 mg / cm 3 up to approximately 0.5 mg / cm 3 to approximately 4.5 mg / cm 3 up to approximately 0.5 mg / cm 3 to approximately 4.0 mg / cm 3 up to approximately 0.5 mg / cm 3 to approximately 3.5 mg / cm 3 up to approximately 0.5 mg / cm 3 to approximately 3.0 mg / cm 3 up to approximately 0.5 mg / cm 3 to approximately 2.5 mg / cm 3 up to approximately 1.0 mg / cm 3 to approximately 6.5 mg / cm 3 up to approximately 1.0 mg / cm 3 to approximately 5.5 mg / cm 3 up to approximately 1.0 mg / cm 3 to approximately 4.5 mg / cm 3 up to approximately 1.0 mg / cm 3 to approximately 3.5 mg / cm 3 up to approximately 2.0 mg / cm 3 to approximately 6.5 mg / cm 3 up to approximately 2.0 mg / cm 3 to approximately 5.5 mg / cm 3 up to approximately 2.0 mg / cm 3 to approximately 4.5 mg / cm 3 up to approximately 3.0 mg / cm 3 to approximately 6.5 mg / cm 3 up to, or about 3.0 mg / cm 3to approximately 6.0 mg / cm 3 That's it.

[0231] In some embodiments, the density of each of the cathode and anode electrode layers on the current collector is independently 6.5 g / cm 3 Less than 6.0 g / cm 3 Less than 5.5g / cm 3 Less than 5.0g / cm 3 Less than 4.5g / cm 3 Less than 4.0 g / cm 3 Less than 3.5g / cm 3 Less than 3.0 g / cm 3 Less than 2.5g / cm 3 Less than 2.0 g / cm 3 Less than 1.5g / cm 3 Less than or equal to 0.5g / cm 3 In some embodiments, the density of each of the cathode and anode electrode layers on the current collector is independently less than 0.5 g / cm 3 Greater than 1.0g / cm 3 Greater than 1.5g / cm 3 Greater than 2.0g / cm 3 Greater than 2.5g / cm 3 Greater than 3.0g / cm 3 Greater than 3.5g / cm 3 Greater than 4.0g / cm 3 Larger, 4.5g / cm 3 Greater than 5.0g / cm 3 Larger: 5.5g / cm 3 Greater than or equal to 6.0 g / cm 3 Greater than.

[0232] In some embodiments, a lithium compound is dissolved in an aqueous solvent-based cathode slurry. Following drying of the slurry, the lithium compound crystallizes from solution, for example, in an electrode layer produced by coating the aforementioned slurry. As a result, in some embodiments, the lithium compound forms small-sized grains. In some embodiments, such grains adhere to the cathode active material particles. This can be advantageous, as the presence of the lithium compound attached to the surface of the cathode active material particles can help reduce lithium ion loss by the cathode active material.

[0233] In some embodiments, the average length of the lithium compound particles in the electrode layer of the cathode is from about 0.1 micron to about 10 microns, from about 0.15 microns to about 10 microns, from about 0.2 microns to about 10 microns, from about 0.25 microns to about 10 microns, from about 0.5 microns to about 10 microns, from about 0.75 microns to about 10 microns, from about 1 micron to about 10 microns, from about 1.25 microns to about 10 microns, from about 1.5 microns to about 10 microns, from about 1.5 microns to about 9 microns, from about 1.5 microns to about 8 microns, from about 1.5 microns to about 7 microns, from about 1.5 microns to about 6 microns, from about 1.5 microns to about 5 microns, from about 1.5 microns to about 4 microns, from about 1.5 microns to about 5 ... up to about 3.5 microns, about 1.5 microns to about 3 microns, about 0.1 microns to about 5 microns, about 0.15 microns to about 5 microns, about 0.2 microns to about 5 microns, about 0.25 microns to about 5 microns, about 0.5 microns to about 5 microns, about 0.75 microns to about 5 microns, about 1 microns to about 5 microns, about 1.25 microns to about 5 microns, about 0.1 microns to about 3 microns, about 0.15 microns to about 3 microns, about 0.2 microns to about 3 microns, about 0.25 microns to about 3 microns, about 0.5 microns to about 3 microns, about 0.75 microns to about 3 microns, about 1 microns to about 3 microns, or about 1.25 microns to about 3 microns.

[0234] In some embodiments, the average length of the lithium compound particles in the cathode electrode layer is less than 10 microns, less than 9 microns, less than 8 microns, less than 7 microns, less than 6 microns, less than 5 microns, less than 4 microns, less than 3.5 microns, less than 3 microns, less than 2.5 microns, less than 2 microns, less than 1.75 microns, less than 1.5 microns, less than 1.25 microns, less than 1 micron, or less than 0.75 microns. In some embodiments, the average length of the lithium compound particles in the cathode electrode layer is greater than 0.1 microns, greater than 0.15 microns, greater than 0.2 microns, greater than 0.25 microns, greater than 0.5 microns, greater than 0.75 microns, greater than 1 micron, greater than 1.25 microns, greater than 1.5 microns, greater than 1.75 microns, greater than 2.0 microns, greater than 2.5 microns, greater than 3 microns, greater than 3.5 microns, greater than 4 microns, or greater than 5 microns.

[0235] In some embodiments, the ratio of the average cathode active material diameter to the average lithium compound particle length in the electrode layer of the cathode is from about 1:1 to about 100:1, from about 1.5:1 to about 100:1, from about 2:1 to about 100:1, from about 2.5:1 to about 100:1, from about 5:1 to about 100:1, from about 10:1 to about 100:1, from about 15:1 to about 100:1, from about 20:1 to about 100:1, from about 25:1 to about 100:1, from about 25:1 to about 90:1, from about 25:1 to about 80:1, from about 25:1 to about 70:1, from about 25:1 to about 6 ... from about 50:1, from about 25:1 to about 45:1, from about 25:1 to about 40:1, from about 25:1 to about 35:1, from about 1:1 to about 25:1, from about 1.5:1 to about 25:1, from about 2:1 to about 25:1, from about 2.5:1 to about 25:1, from about 5:1 to about 25:1, from about 10:1 to about 25:1, from about 1:1 to about 50:1, from about 1.5:1 to about 50:1, from about 2:1 to about 50:1, from about 2.5:1 to about 50:1, from about 5:1 to about 50:1, from about 10:1 to about 50:1, from about 15:1 to about 50:1, or from about 20:1 to about 50:1.

[0236] In some embodiments, the ratio of the average cathode active material diameter to the average lithium compound particle length in the electrode layer of the cathode is greater than 1:1, greater than 1.5:1, greater than 2:1, greater than 2.5:1, greater than 5:1, greater than 10:1, greater than 15:1, greater than 20:1, greater than 25:1, greater than 30:1, greater than 35:1, greater than 40:1, greater than 45:1, greater than 50:1, greater than 60:1, greater than 70:1, or greater than 80:1. In some embodiments, the ratio of the average cathode active material diameter to the average lithium compound particle length in the electrode layer of the cathode is less than 100:1, less than 90:1, less than 80:1, less than 70:1, less than 60:1, less than 50:1, less than 45:1, less than 40:1, less than 35:1, less than 30:1, less than 25:1, less than 20:1, less than 15:1, less than 10:1, less than 5:1, less than 2.5:1, or less than 2:1.

[0237] The cathodes prepared according to the present invention exhibit strong adhesion of the electrode layer to the current collector. It is important for the electrode layer to have good peel strength to the current collector while preventing delamination or separation of the electrode, which can significantly affect the mechanical stability of the electrode and the cyclability of the battery. Therefore, the electrode should have sufficient peel strength to withstand the rigors of battery manufacturing.

[0238] In some embodiments, the peel strength between the current collector and cathode electrode layers is from about 1.0 N / cm to about 8.0 N / cm, from about 1.0 N / cm to about 7.0 N / cm, from about 1.0 N / cm to about 6.0 N / cm, from about 1.0 N / cm to about 5.0 N / cm, from about 1.0 N / cm to about 4.0 N / cm, from about 1.0 N / cm to about 3.0 N / cm, from about 1.0 N / cm to about 2.5 N / cm, from about 1.0 N / cm to about 2.0 N / cm, from about 1.2 N / cm to about 3.0 N / cm, from about 1.2 N / cm to about 2.5 N / cm, from about 1.2 N / cm to about 2.0 N / cm, from about 1.5 N / cm to about 3.0 N / cm. / cm, from about 1.5 N / cm to about 2.5 N / cm, from about 1.5 N / cm to about 2.0 N / cm, from about 1.8 N / cm to about 3.0 N / cm, from about 1.8 N / cm to about 2.5 N / cm, from about 2.0 N / cm to about 6.0 N / cm, from about 2.0 N / cm to about 5.0 N / cm, from about 2.0 N / cm to about 3.0 N / cm, from about 2.0 N / cm to about 2.5 N / cm, from about 2.2 N / cm to about 3.0 N / cm, from about 2.5 N / cm to about 3.0 N / cm, from about 3.0 N / cm to about 8.0 N / cm, from about 3.0 N / cm to about 6.0 N / cm, or from about 4.0 N / cm to about 6.0 N / cm.

[0239] In some embodiments, the peel strength between the current collector and cathode electrode layers is greater than 1.0 N / cm, greater than 1.2 N / cm, greater than 1.5 N / cm, greater than 2.0 N / cm, greater than 2.2 N / cm, greater than 2.5 N / cm, greater than 3.0 N / cm, greater than 3.5 N / cm, greater than 4.5 N / cm, greater than 5.0 N / cm, greater than 5.5 N / cm, greater than 6.0 N / cm, greater than 6.5 N / cm, or greater than 7.0 N / cm. In some embodiments, the peel strength between the electrode layer of the current collector and the cathode 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.

[0240] The method presented herein has the advantage of being able to use aqueous solvents in the manufacturing process. It can improve safety by eliminating the need to handle or reuse hazardous organic solvents, as well as save processing time and equipment. Furthermore, costs are reduced by simplifying the overall process. Therefore, this method is particularly suitable for industrial processes due to its ease of handling and low cost.

[0241] As described above, adding a lithium compound to an aqueous-solvent-based cathode slurry containing the water-compatible copolymer binder described herein can compensate for the irreversible lithium ion loss during the first cycling of a battery containing a cathode produced with such an aqueous-solvent-based cathode slurry. The water-soluble nature of the lithium compound and the binding ability of the water-compatible copolymer binder in water both contribute to good dispersion of various cathode materials, including the lithium compound, within the cathode slurry. As a result, consistently low resistance and uniform pore distribution are also achieved within the aforementioned cathode, thereby improving the electrochemical performance of a battery containing such a cathode. Therefore, the development of an aqueous-solvent-based cathode slurry can improve battery performance, such as cyclability and capacity, and is achieved by the present invention.

[0242] Also provided herein is an electrode assembly including a cathode prepared by the method described below. The electrode assembly includes at least one cathode, at least one anode, and at least one separator disposed between the cathode and the anode.

[0243] It should be noted that the present invention is not limited to lithium-ion batteries. Other metal-ion batteries may use other metal compounds that are soluble in aqueous solvents and are compatible with the battery chemistry to compensate for irreversible capacity loss due to SEI formation. For example, sodium-ion batteries may use sodium azide (NaN), sodium nitrite (NaNO), sodium chloride (NaCl), sodium deltamate (NaCO), sodium squarate (NaCO), sodium croconic acid (NaCO), sodium rhodizonate (NaCO), sodium ketomalonate (NaCO), sodium diketosuccinate (NaCO), sodium hydrazide, sodium fluoride (NaF), sodium bromide (NaBr), sodium iodide (NaI ... subSodium analogs of the indicated lithium compounds may be used, such as sodium sulfate (NaSO), sodium selenite (NaSeO), sodium nitrate (NaNO), sodium acetate (CHCOONa), the sodium salt of 3,4-dihydroxybenzoic acid (NaDHBA), the sodium salt of 3,4-dihydroxybutyric acid, sodium formate, sodium hydroxide, sodium dodecyl sulfate, sodium succinate, sodium citrate, or combinations thereof.

[0244] Some non-limiting examples of sodium compounds include sodium salts of organic acids, RCOONa, where R is an alkyl, benzyl, or aryl group, sodium salts of organic acids carrying more than one carboxylic acid group, such as oxalic acid, citric acid, fumaric acid, etc., and sodium salts of multiply substituted benzene rings containing carboxyl, such as trimellitic acid, 1,2,4,5-benzenetetracarboxylic acid, mellitic acid, etc. Application of the sodium ions disclosed herein in the cathode of a sodium ion battery provides similar results as the lithium compounds demonstrated in the present invention.

[0245] The following examples are presented to illustrate embodiments of the invention, but are not intended to limit the invention to the specific embodiments described. Also, unless otherwise indicated, all parts and percentages are by weight. All numerical values ​​are approximate. When numerical ranges are given, it should be understood that embodiments outside the stated ranges may still fall within the scope of the invention. Specific details described in each example should not be construed as necessary features of the invention. (Example)

[0246] The composite volume resistivity of the cathode and the interface resistance between the cathode layers and the current collector were measured using an electrode resistance measurement system (RM2610, HIOKI).

[0247] The adhesive strength of the dry binder layer was measured by a tension tester (DZ-106A, obtained from Dongguan Zonhow Test Equipment Co. Ltd., China). This test measures the average force required to peel the binder layer from the current collector at an angle of 180° in several Newtons. The average roughness depth (R z ) is 2 microns. The copolymer binder is coated on a current collector and dried to obtain a binder layer with a thickness of 10 to 12 microns. The coated current collector is then placed in an environment with a constant temperature of 25°C and a humidity of 50 to 60% for 30 minutes. A strip of adhesive tape (3M, US, No. 810 model) measuring 18 mm wide and 20 mm long is applied to the surface of the binder layer. A strip of binder is clipped to the testing machine, and the tape is folded back on itself at 180 degrees, placed on a movable jaw at room temperature, and pulled at a peel rate of 300 mm per minute. The maximum measured peel strength is taken as the adhesive force. The measurement was repeated three times to find the average value. (Example 1) A) Preparation of binder material

[0248] 7.45 g of sodium hydroxide (NaOH) was added to a round-bottom flask containing 380 g of distilled water, and the mixture was stirred at 80 rpm for 30 minutes to obtain a primary suspension.

[0249] 16.77 g of acrylic acid was added to the first suspension, and the mixture was further stirred at 80 rpm for 30 minutes to obtain a second suspension.

[0250] 7.19 g of acrylamide was dissolved in 10 g of distilled water to form an acrylamide solution. Then, 17.19 g 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.

[0251] 35.95 g of acrylonitrile was added to the third suspension, and the mixture was further stirred at 80 rpm for 10 minutes to obtain a fourth suspension.

[0252] Furthermore, 0.015 g of a water-soluble free radical initiator (ammonia persulfate, APS; obtained from Aladdin Industries Corporation, China) was dissolved in 3 g of distilled water, and 0.0075 g of a reducing agent (sodium bisulfite; obtained from Tianjin Damao Chemical Reagent Factory, China) was dissolved in 1.5 g of distilled water. 3.015 g of the APS solution and 1.5075 g of the sodium bisulfite solution were added to the fourth suspension. The mixture was stirred at 55°C and 200 rpm for 24 hours to obtain a fifth suspension.

[0253] After the reaction was complete, the temperature of the fifth suspension was reduced to 25°C. 3.72 g of NaOH was dissolved in 400 g of distilled water. Then, 403.72 g of sodium hydroxide solution was added dropwise to the fifth suspension to adjust the pH to 7.3 and form a binder material. The binder material was filtered using a 200 micrometer nylon mesh. The solid content of the binder material was 8.88 wt%. The adhesive strength between the copolymer binder and the current collector was 3.41 N / cm. The components and their respective proportions of the copolymer binder of Example 1 are shown in Table 2 below. B) Preparation of the positive electrode

[0254] A first suspension was prepared by dispersing 1.85 g of lithium compound LiNo2 in 14.48 g of deionized water in a 50 mL round-bottom flask by stirring with an overhead stirrer (R20, IKA). Afterwards, the first suspension was further stirred at a speed of 500 rpm for approximately 10 minutes.

[0255] Then, 22.52 g of the binder material (8.88 wt % solids) was added to the first suspension while stirring with an overhead stirrer. The mixture was stirred at 500 rpm for approximately 30 minutes. 3.15 g of a conductive agent (Super P; obtained from Timcal Ltd, Bodio, Switzerland) was added to the mixture and stirred at 1,200 rpm for 30 minutes to obtain a second suspension.

[0256] A third suspension was prepared by dispersing 58.0 g of NMC811 (obtained from Shandong Tianjiao New Energy Co., Ltd., China) in the second suspension at 25°C while stirring with an overhead stirrer. The third suspension was then degassed under a pressure of approximately 10 kPa for 1 hour. The third suspension was further stirred at 1200 rpm at 25°C for approximately 90 minutes to form a homogenized cathode slurry. The components of the cathode slurry in Example 1 are shown in Table 2 below. The concentration of the lithium compound in the cathode slurry was 1.0 M, the solubility ratio of the lithium compound in the cathode slurry was 18.9, and the solids content of the cathode slurry was 65.00%.

[0257] The homogenized cathode slurry was coated onto one side of an aluminum foil with a thickness of 16 μm as a current collector using a doctor blade coater with a gap width of 60 μm at room temperature. The 55 μm slurry film coated on the aluminum foil was dried in an electrically heated oven at 80°C to form a cathode electrode layer. The drying time was approximately 120 minutes. The electrode was then pressed to reduce the thickness of the cathode electrode layer to 34 μm. The areal density of the cathode electrode layer on the current collector was 16.00 mg / cm. 2The composite volume resistivity of the cathode of Example 1 and the interface resistance between the cathode layer and the current collector were measured and are shown in Table 4 below. C) Preparation of the negative electrode

[0258] The negative electrode slurry was prepared by mixing 90 wt% graphite (BTR New Energy Materials Inc., Shenzhen, Guangdong, China) as a binder, 1.5 wt% carboxymethyl cellulose (CMC, BSH-12, DKS Co. Ltd., Japan), and 3.5 wt% SBR (AL-2001, NIPPON A&L INC., Japan) with 5 wt% carbon black as a conductive agent in deionized water. The solids content of the anode slurry was 50 wt%. The slurry was coated onto one side of a copper foil with a thickness of 8 μm using a doctor blade with a gap width of approximately 55 μm. The coating film on the copper foil was dried in a hot air dryer at approximately 50 °C for 120 minutes to obtain the negative electrode. The electrode was then pressed to reduce the coating thickness to 30 μm and the areal density to 10 mg / cm. 2 It was. D) Coin cell assembly

[0259] CR2032 coin-type Li cells were assembled in an argon-filled glove box. The coated cathode and anode sheets were cut into disc-shaped positive and negative electrodes. The electrode assembly was then assembled by alternately stacking the cathode and anode plates and packaged in a CR2032-type stainless steel package. The cathode and anode plates were kept separate by a separator. The separator was a ceramic, microporous thin film made of nonwoven fabric (MPM, Japan). Its thickness was approximately 25 μm. The electrode assembly was then dried under vacuum at 105°C for approximately 16 hours in a box-type resistance oven (DZF-6020, obtained from Shenzhen Kejing Star Technology Co. Ltd., China).

[0260] The electrolyte was then injected into the case holding the packed electrodes under a high-purity argon atmosphere with moisture and oxygen contents each below 3 ppm. The electrolyte was a solution of LiPF6 (1M) in a mixture of ethylene carbonate (EC), ethyl methyl carbonate (EMC), and dimethyl carbonate (DMC) in a 1:1:1 volume ratio. After filling with the electrolyte, the coin cells were vacuum sealed and mechanically pressed using a standard circular-shaped punch die. E) Electrochemical measurements

[0261] The coin cells were analyzed in constant current mode using a multi-channel battery tester (BTS-4008-5V10mA, obtained from Neware Electronics Co. Ltd, China). The first cycle at C / 20 was completed and the discharge capacity was recorded. The coin cells were then repeatedly charged and discharged at a rate of C / 2. Charge / discharge cycling tests of the cells were performed between 3.0V and 4.3V at 25°C and a current density of C / 2 to obtain the capacity retained at 50 cycles. The electrochemical performance of the coin cells of Example 1 is shown in Table 2 below. Preparation of binder material for Example 2-5

[0262] The binder material is prepared by the method described in Example 1. Example 2: Preparation of the positive electrode

[0263] The cathode was prepared by the method described in Example 1, except that 0.93 g of the lithium compound LiNO2 was added in the preparation of the first suspension and 4.07 g of the conductive agent was added in the preparation of the second suspension of the cathode slurry. The concentration of the lithium compound in the cathode slurry was 0.5 M, the solubility ratio of the lithium compound in the cathode slurry was 37.8, and the solids content of the cathode slurry was 65.00%. Example 3: Preparation of the positive electrode

[0264] The cathode was prepared by the method described in Example 1, except that 3.71 g of the lithium compound LiNO2 was added in the preparation of the first suspension, 2.29 g of the conductive agent was added in the preparation of the second suspension, and 57.0 g of the cathode active material NMC811 was added in the preparation of the third suspension of the cathode slurry. The concentration of the lithium compound in the cathode slurry was 2.0 M, the solubility ratio of the lithium compound in the cathode slurry was 9.45, and the solids content of the cathode slurry was 65.00%. Example 4: Preparation of the positive electrode

[0265] The cathode was prepared by the method described in Example 1, except that 0.02 g of the lithium compound LiNO2 was added in the preparation of the first suspension and 4.98 g of the conductive agent was added in the preparation of the second suspension of the cathode slurry. The concentration of the lithium compound in the cathode slurry was 0.01 M, the solubility ratio of the lithium compound in the cathode slurry was 1890, and the solids content of the cathode slurry was 65.00%. Example 5: Preparation of the positive electrode

[0266] The cathode was prepared by the method described in Example 1, except that 2.20 g of the lithium compound lithium squarate was added in preparing the first suspension and 2.80 g of the conductive agent was added in preparing the second suspension of the cathode slurry. The concentration of the lithium compound in the cathode slurry was 0.5 M, the solubility ratio of the lithium compound in the cathode slurry was 3.18, while the lithium ion concentration of the lithium compound in the cathode slurry was 1.0 M, and the solids content of the cathode slurry was 65.00%. Example 6 A) Preparation of binder material

[0267] 18.15 g of sodium hydroxide (NaOH) was added to a round-bottom flask containing 380 g of distilled water, and the mixture was stirred at 80 rpm for 30 minutes to obtain a primary suspension.

[0268] 36.04 g of acrylic acid was added to the first suspension, and the mixture was further stirred at 80 rpm for 30 minutes to obtain a second suspension.

[0269] 19.04 g of acrylamide was dissolved in 10 g of distilled water to form an acrylamide solution. Then, 29.04 g 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.

[0270] 12.92 g of acrylonitrile was added to the third suspension, and the mixture was further stirred at 80 rpm for 10 minutes to obtain a fourth suspension.

[0271] Furthermore, 0.015 g of a water-soluble free radical initiator (ammonia persulfate, APS; obtained from Aladdin Industries Corporation, China) was dissolved in 3 g of distilled water, and 0.0075 g of a reducing agent (sodium bisulfite; obtained from Tianjin Damao Chemical Reagent Factory, China) was dissolved in 1.5 g of distilled water. 3.015 g of the APS solution and 1.5075 g of the sodium bisulfite solution were added to the fourth suspension. The mixture was stirred at 55°C and 200 rpm for 24 hours to obtain a fifth suspension.

[0272] After the reaction was complete, the temperature of the fifth suspension was reduced to 25°C. 3.72 g of NaOH was dissolved in 400 g of distilled water. Then, 403.72 g of sodium hydroxide solution was added dropwise to the fifth suspension to adjust the pH to 7.3 and form a binder material. The binder material was filtered using a 200 micrometer nylon mesh. The solid content of the binder material was 9.00 wt%. The adhesive strength between the copolymer binder and the current collector was 3.27 N / cm. The components and their respective proportions of the copolymer binder of Example 6 are shown in Table 2 below. B) Preparation of the positive electrode

[0273] The cathode was prepared by the method described in Example 1, except that 14.78 g of diwater was added in preparing the first suspension and 22.22 g of binder material (9.00 wt % solids) was added in preparing the second suspension of the cathode slurry. The concentration of the lithium compound in the cathode slurry was 1.0 M, the solubility ratio of the lithium compound in the cathode slurry was 18.9, and the solids content of the cathode slurry was 65.00%. Preparation of binder material for Example 7

[0274] The binder material is prepared by the method described in Example 6. Preparation of the positive electrode in Example 7

[0275] A cathode was prepared by the method described in Example 6, except that 2.20 g of the lithium compound lithium squarate was added in preparing the first suspension and 2.80 g of the conductive agent was added in preparing the second suspension of the cathode slurry. The concentration of the lithium compound in the cathode slurry was 0.5 M, the solubility ratio of the lithium compound in the cathode slurry was 3.18, while the lithium ion concentration of the lithium compound in the cathode slurry was 1.0 M, and the solids content of the cathode slurry was 65.00%. Preparation of binder materials for Examples 8-12

[0276] The binder material is prepared by the method described in Example 1. Preparation of the positive electrode of Example 8

[0277] A first suspension was prepared by dispersing 1.78 g of lithium compound lithium oxalate in 14.48 g of deionized water in a 50 mL round-bottom flask by stirring with an overhead stirrer (R20, IKA). Afterwards, the first suspension was further stirred at a speed of 500 rpm for approximately 10 minutes.

[0278] Then, 22.52 g of the binder material (8.88 wt % solids) was added to the first suspension while stirring with an overhead stirrer. The mixture was stirred at 500 rpm for approximately 30 minutes. 3.22 g of a conductive agent (Super P; obtained from Timcal Ltd, Bodio, Switzerland) was added to the mixture and stirred at 1200 rpm for 30 minutes to obtain a second suspension.

[0279] A third suspension was prepared by dispersing 58.0 g of LNMO (obtained from Chengdu Xingneng New Materials Co., Ltd., China) in the second suspension at 25°C while stirring with an overhead stirrer. The third suspension was then degassed under a pressure of approximately 10 kPa for 1 hour. The third suspension was further stirred at 25°C and 1200 rpm for approximately 90 minutes to form a homogenized cathode slurry. The components of the cathode slurry of Example 8 are shown in Table 2 below. The concentration of the lithium compound in the cathode slurry was 0.5 M, the solubility ratio of the lithium compound in the cathode slurry was 1.56, while the lithium ion concentration of the lithium compound in the cathode slurry was 1.0 M, and the solids content of the cathode slurry was 65.00%.

[0280] The homogenized cathode slurry was coated onto one side of an aluminum foil with a thickness of 16 μm as a current collector using a doctor blade coater with a gap width of 60 μm at room temperature. The 55 μm slurry film coated on the aluminum foil was dried in an electrically heated oven at 80°C to form a cathode electrode layer. The drying time was approximately 120 minutes. The electrode was then pressed to reduce the thickness of the cathode electrode layer to 34 μm. The areal density of the cathode electrode layer on the current collector was 16.00 mg / cm. 2The composite volume resistivity of the cathode of Example 1 and the interface resistance between the cathode layer and the current collector were measured and are shown in Table 4 below. Preparation of the positive electrode of Example 9

[0281] The cathode was prepared by the method described in Example 8, except that 0.89 g of the lithium compound lithium oxalate was added in preparing the first suspension and 4.11 g of the conductive agent was added in preparing the second suspension of the cathode slurry. The concentration of the lithium compound in the cathode slurry was 0.25 M, the solubility ratio of the lithium compound in the cathode slurry was 3.12, while the lithium ion concentration of the lithium compound in the cathode slurry was 0.5 M, and the solids content of the cathode slurry was 65.00%. Preparation of the positive electrode of Example 10

[0282] The cathode was prepared by the method described in Example 8, except that 3.67 g of the lithium compound lithium citrate was added in the preparation of the first suspension, 2.33 g of the conductive agent was added in the preparation of the second suspension, and 57.0 g of the cathode active material LNMO was added in the preparation of the third suspension of the cathode slurry. The concentration of the lithium compound in the cathode slurry was 0.5 M, the solubility ratio of the lithium compound in the cathode slurry was 4.76, while the lithium ion concentration of the lithium compound in the cathode slurry was 1.5 M, and the solids content of the cathode slurry was 65.00%. Preparation of the positive electrode of Example 11

[0283] The cathode was prepared by the method described in Example 8, except that 0.84 g of the lithium compound LiOH was added in the preparation of the first suspension and 4.16 g of the conductive agent was added in the preparation of the second suspension of the cathode slurry. The concentration of the lithium compound in the cathode slurry was 1.0 M, the solubility ratio of the lithium compound in the cathode slurry was 4.18, and the solids content of the cathode slurry was 65.00%. Preparation of the positive electrode of Example 12

[0284] The cathode was prepared by the method described in Example 8, except that 2.38 g of the lithium compound lithium dodecyl sulfate was added in the preparation of the first suspension and 2.62 g of the conductive agent was added in the preparation of the second suspension of the cathode slurry. The concentration of the lithium compound in the cathode slurry was 0.25 M, the solubility ratio of the lithium compound in the cathode slurry was 1.04, and the solids content of the cathode slurry was 65.00%. Preparation of binder materials for Examples 13-15

[0285] The binder material is prepared by the method described in Example 6. Preparation of the positive electrode of Example 13

[0286] A cathode was prepared by the method described in Example 8, except that 14.78 g of diwater was added in preparing the first suspension and 22.22 g of binder material (9.00 wt % solids) was added in preparing the second suspension of the cathode slurry. The concentration of the lithium compound in the cathode slurry was 0.5 M, the solubility ratio of the lithium compound in the cathode slurry was 1.56, while the lithium ion concentration of the lithium compound in the cathode slurry was 1.0 M, and the solids content of the cathode slurry was 65.00%. Preparation of the positive electrode of Example 14

[0287] A cathode was prepared by the method described in Example 11, except that 14.78 g of diwater was added in preparing the first suspension and 22.22 g of binder material (9.00 wt % solids) was added in preparing the second suspension of the cathode slurry. The concentration of the lithium compound in the cathode slurry was 1.0 M, the solubility ratio of the lithium compound in the cathode slurry was 4.18, and the solids content of the cathode slurry was 65.00%. Preparation of the positive electrode of Example 15

[0288] The cathode was prepared by the method described in Example 12, except that 14.78 g of diwater was added in the preparation of the first suspension and 22.22 g of binder material (9.00 wt % solids) was added in the preparation of the second suspension of the cathode slurry. The concentration of the lithium compound in the cathode slurry was 0.25 M, the solubility ratio of the lithium compound in the cathode slurry was 1.04, and the solids content of the cathode slurry was 65.00%. Example 16 A) Preparation of binder material

[0289] 27.27 g of sodium hydroxide (NaOH) was added to a round-bottom flask containing 380 g of distilled water, and the mixture was stirred at 80 rpm for 30 minutes to obtain a primary suspension.

[0290] 52.48 g of acrylic acid was added to the first suspension. The mixture was further stirred at 80 rpm for 30 minutes to obtain a second suspension.

[0291] 8.63 g of acrylamide was dissolved in 10 g of distilled water to form an acrylamide solution. Then, 18.63 g 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.

[0292] 8.59 g of acrylonitrile was added to the third suspension. The mixture was further stirred at 80 rpm for 10 minutes to obtain a fourth suspension.

[0293] Furthermore, 0.015 g of a water-soluble free radical initiator (ammonia persulfate, APS; obtained from Aladdin Industries Corporation, China) was dissolved in 3 g of distilled water, and 0.0075 g of a reducing agent (sodium bisulfite; obtained from Tianjin Damao Chemical Reagent Factory, China) was dissolved in 1.5 g of distilled water. 3.015 g of the APS solution and 1.5075 g of the sodium bisulfite solution were added to the fourth suspension. The mixture was stirred at 55°C and 200 rpm for 24 hours to obtain a fifth suspension.

[0294] After the reaction was complete, the temperature of the fifth suspension was lowered to 25°C. 3.72g of NaOH was dissolved in 400g of distilled water. Then, 403.72g of sodium hydroxide solution was added dropwise to the fifth suspension to adjust the pH to 7.3 and form a binder material. The binder material was filtered using a 200 micrometer nylon mesh. The solid content of the binder material was 9.14wt%. The components and their respective proportions of the copolymer binder of Example 16 are shown in Table 2 below. B) Preparation of the positive electrode

[0295] The cathode was prepared by the method described in Example 1, except that 15.12 g of diwater was added in the preparation of the first suspension and 21.18 g of binder material (9.14 wt % solids) was added in the preparation of the second suspension of the cathode slurry. The concentration of the lithium compound in the cathode slurry was 1.0 M, the solubility ratio of the lithium compound in the cathode slurry was 18.9, and the solids content of the cathode slurry was 65.00%. Example 17 A) Preparation of binder material

[0296] 5.02 g of sodium hydroxide (NaOH) was added to a round-bottom flask containing 380 g of distilled water, and the mixture was stirred at 80 rpm for 30 minutes to obtain a primary suspension.

[0297] 12.39 g of acrylic acid was added to the first suspension. The mixture was further stirred at 80 rpm for 30 minutes to obtain a second suspension.

[0298] 23.73 g of acrylamide was dissolved in 10 g of distilled water to form an acrylamide solution. Then, 33.73 g 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.

[0299] 26.84 g of acrylonitrile was added to the third suspension. The mixture was further stirred at 80 rpm for 10 minutes to obtain a fourth suspension.

[0300] Furthermore, 0.015 g of a water-soluble free radical initiator (ammonia persulfate, APS; obtained from Aladdin Industries Corporation, China) was dissolved in 3 g of distilled water, and 0.0075 g of a reducing agent (sodium bisulfite; obtained from Tianjin Damao Chemical Reagent Factory, China) was dissolved in 1.5 g of distilled water. 3.015 g of the APS solution and 1.5075 g of the sodium bisulfite solution were added to the fourth suspension. The mixture was stirred at 55°C and 200 rpm for 24 hours to obtain a fifth suspension.

[0301] After the reaction was complete, the temperature of the fifth suspension was lowered to 25°C. 3.72g of NaOH was dissolved in 400g of distilled water. Then, 403.72g of sodium hydroxide solution was added dropwise to the fifth suspension to adjust the pH to 7.3 and form a binder material. The binder material was filtered using a 200 micrometer nylon mesh. The solid content of the binder material was 8.64wt%. The components and their respective proportions of the copolymer binder of Example 17 are shown in Table 2 below. Preparation of the positive electrode

[0302] The cathode was prepared by the method described in Example 1, except that 13.85 g of diwater was added in preparing the first suspension and 23.15 g of binder material (8.64 wt % solids) was added in preparing the second suspension of the cathode slurry. The concentration of the lithium compound in the cathode slurry was 1.0 M, the solubility ratio of the lithium compound in the cathode slurry was 18.9, and the solids content of the cathode slurry was 65.00%. Example 18 A) Preparation of binder material

[0303] 12.30 g of sodium hydroxide (NaOH) was added to a round-bottom flask containing 380 g of distilled water, and the mixture was stirred at 80 rpm for 30 minutes to obtain a primary suspension.

[0304] 25.51 g of acrylic acid was added to the first suspension. The mixture was further stirred at 80 rpm for 30 minutes to obtain a second suspension.

[0305] 14.38 g of acrylamide was dissolved in 10 g of distilled water to form an acrylamide solution. Then, 24.38 g 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.

[0306] 24.15 g of acrylonitrile was added to the third suspension. The mixture was further stirred at 80 rpm for 10 minutes to obtain a fourth suspension.

[0307] Furthermore, 0.015 g of a water-soluble free radical initiator (ammonia persulfate, APS; obtained from Aladdin Industries Corporation, China) was dissolved in 3 g of distilled water, and 0.0075 g of a reducing agent (sodium bisulfite; obtained from Tianjin Damao Chemical Reagent Factory, China) was dissolved in 1.5 g of distilled water. 3.015 g of the APS solution and 1.5075 g of the sodium bisulfite solution were added to the fourth suspension. The mixture was stirred at 55°C and 200 rpm for 24 hours to obtain a fifth suspension.

[0308] After the reaction was complete, the temperature of the fifth suspension was lowered to 25°C. 3.72g of NaOH was dissolved in 400g of distilled water. Then, 403.72g of sodium hydroxide solution was added dropwise to the fifth suspension to adjust the pH to 7.3 and form a binder material. The binder material was filtered using a 200 micrometer nylon mesh. The solid content of the binder material was 8.32wt%. The components and their respective proportions of the copolymer binder of Example 18 are shown in Table 2 below. B) Preparation of the positive electrode

[0309] The cathode was prepared by the method described in Example 1, except that 12.96 g of diwater was added in preparing the first suspension and 24.04 g of binder material (8.32 wt % solids) was added in preparing the second suspension of the cathode slurry. The concentration of the lithium compound in the cathode slurry was 1.0 M, the solubility ratio of the lithium compound in the cathode slurry was 18.9, and the solids content of the cathode slurry was 65.00%. Preparation of binder material for Example 19

[0310] The binder material is prepared by the method described in Example 16. Preparation of the positive electrode of Example 19

[0311] A cathode was prepared by the method described in Example 8, except that 15.12 g of diwater was added in preparing the first suspension and 21.88 g of binder material (9.14 wt % solids) was added in preparing the second suspension of the cathode slurry. The concentration of the lithium compound in the cathode slurry was 0.5 M, the solubility ratio of the lithium compound in the cathode slurry was 1.56, while the lithium ion concentration of the lithium compound in the cathode slurry was 1.0 M, and the solids content of the cathode slurry was 65.00%. Comparative Example 1 A) Preparation of binder material

[0312] The binder material is prepared by the method described in Example 1. B) Preparation of the positive electrode

[0313] The cathode was prepared by the method described in Example 1, except that the lithium compound was added in the preparation of the first suspension and 5.0 g of the conductive agent was added in the preparation of the second suspension of the cathode slurry. The composite volume resistivity and the interfacial resistance between the cathode layer and the current collector of the cathode of Comparative Example 1 were measured and are shown in Table 4 below. Comparative Example 2 A) Preparation of binder material

[0314] The binder material is prepared by the method described in Example 6. B) Preparation of the positive electrode

[0315] The cathode was prepared by the method described in Example 6, except that the lithium compound was added in the preparation of the first suspension and 5.0 g of the conductive agent was added in the preparation of the second suspension of the cathode slurry. Comparative Example 3 A) Preparation of binder material

[0316] The binder material is prepared by the method described in Example 8. B) Preparation of the positive electrode

[0317] The cathode was prepared by the method described in Example 8, except that the lithium compound added in the preparation of the first suspension and 5.0 g of the conductive agent added in the preparation of the second suspension of the cathode slurry were omitted. Comparative Example 4 A) Preparation of binder material

[0318] The binder material is prepared by the method described in Example 13. B) Preparation of the positive electrode

[0319] The cathode was prepared by the method described in Example 13, except that the lithium compound was added in the preparation of the first suspension and 5.0 g of the conductive agent was added in the preparation of the second suspension of the cathode slurry. Preparation of the positive electrode of Comparative Example 5.

[0320] A first suspension was prepared by dispersing 1.85 g of lithium compound LiNO2 in 14.48 g of NMP in a 50 mL round-bottom flask by stirring with an overhead stirrer (R20, IKA). Afterwards, the first suspension was further stirred at a speed of 500 rpm for approximately 10 min.

[0321] Then, 2 g of the binder material PVDF (Sigma-Aldrich, USA) and 20.52 g of NMP were added to the first suspension while stirring with an overhead stirrer. The mixture was stirred at 500 rpm for approximately 30 minutes. 3.15 g of a conductivity agent (Super P; obtained from Timcal Ltd, Bodio, Switzerland) was added to the mixture and stirred at 1200 rpm for 30 minutes to obtain a second suspension.

[0322] A third suspension was prepared by dispersing 58.0 g of NMC811 (obtained from Shandong Tianjiao New Energy Co., Ltd., China) in the second suspension at 25°C while stirring with an overhead stirrer. The third suspension was then degassed under a pressure of approximately 10 kPa for 1 hour. The third suspension was further stirred at 25°C and 1200 rpm for approximately 90 minutes to form a homogenized cathode slurry. The components of the cathode slurry of Comparative Example 5 are shown in Table 3 below. The moles of lithium compound present in the cathode slurry of Comparative Example 5 were the same as those in Example 1, and the solids content of the cathode slurry was 65.00%.

[0323] The homogenized cathode slurry was coated onto one side of an aluminum foil with a thickness of 16 μm as a current collector using a doctor blade coater with a gap width of 60 μm at room temperature. The 55 μm slurry film coated on the aluminum foil was dried in an electrically heated oven at 80°C to form a cathode electrode layer. The drying time was approximately 120 minutes. The electrode was then pressed to reduce the thickness of the cathode electrode layer to 34 μm. The areal density of the cathode electrode layer on the current collector was 16.00 mg / cm. 2 The composite volume resistivity of the cathode of Comparative Example 5 and the interface resistance between the cathode layer and the current collector were measured and are shown in Table 4 below. Preparation of the positive electrode of Comparative Example 6

[0324] The positive electrode was prepared by the method described in Comparative Example 5, except that the lithium compound added in the preparation of the first suspension and 5.0 g of the conductive agent added in the preparation of the second suspension of the cathode slurry were omitted. The composite volume resistivity and the interfacial resistance between the cathode layer and the current collector of the cathode of Comparative Example 6 were measured and are shown in Table 4 below. Preparation of the positive electrode of Comparative Example 7

[0325] The cathode was prepared by the method described in Example 1, except that 2 g of polyacrylic acid (PAA, Sigma-Aldrich, USA), 20.52 g of diwater, and 3.15 g of conductive agent were added in the preparation of the second suspension of the cathode slurry. The concentration of the lithium compound in the cathode slurry was 1.0 M, the solubility ratio of the lithium compound in the cathode slurry was 18.9, and the solid content of the cathode slurry was 65.00%. Preparation of the positive electrode of Comparative Example 8

[0326] The cathode was prepared by the method described in Example 1, except that 0.6 g of carboxymethyl cellulose (CMC, BSH-12, DKS Co. Ltd., Japan), 1.4 g of SBR (AL-2001, NIPPON A&L INC., Japan), 20.52 g of distilled water, and 3.15 g of conductive agent (SuperP; obtained from Timcal Ltd, Bodio, Switzerland) were added in the preparation of the second suspension of the cathode slurry. The concentration of the lithium compound in the cathode slurry was 1.0 M, the solubility ratio of the lithium compound in the cathode slurry was 18.9, and the solids content of the cathode slurry was 65.00%. Comparative Example 9 Preparation of binder material

[0327] The binder material was prepared by the method described in Example 1, except that in the preparation of the copolymer binder, 2.19 g of sodium hydroxide was added in the preparation of the first suspension, 7.29 g of acrylic acid was added in the preparation of the second suspension, 12.94 g of acrylamide was added in the preparation of the third suspension, and 38.64 g of acrylonitrile was added in the preparation of the fourth suspension. The solids content of the binder material was 7.92 wt %. The components and their proportions of the copolymer binder of Comparative Example 9 are shown in Table 3 below. B) Preparation of the positive electrode

[0328] The cathode was prepared by the method described in Example 1, except that 11.75 g of diwater was added in preparing the first suspension, and 25.25 g of the binder material (7.92 wt % solids) was added in preparing the second suspension of the cathode slurry. The concentration of the lithium compound in the cathode slurry was 1.0 M, the solubility ratio of the lithium compound in the cathode slurry was 18.9, and the solids content of the cathode slurry was 65.00%. Comparative Example 10 A) Preparation of binder material

[0329] The binder material was prepared by the method described in Example 1, except that in the copolymer binder preparation, 30.51 g of sodium hydroxide was added in the first suspension preparation, 58.31 g of acrylic acid was added in the second suspension preparation, acrylamide was added in the third suspension preparation, and 10.73 g of acrylonitrile was added in the fourth suspension preparation. The solids content of the binder material was 9.46 wt %. The components and their proportions of the copolymer binder of Comparative Example 10 are shown in Table 3 below. B) Preparation of the positive electrode

[0330] The cathode was prepared by the method described in Example 1, except that 15.86 g of diwater was added in preparing the first suspension and 21.14 g of the binder material (9.46 wt % solids) was added in preparing the second suspension of the cathode slurry. The concentration of the lithium compound in the cathode slurry was 1.0 M, the solubility ratio of the lithium compound in the cathode slurry was 18.9, and the solids content of the cathode slurry was 65.00%. Comparative Example 11 A) Preparation of binder material

[0331] The binder material was prepared by the method described in Example 1, except that in the copolymer binder preparation, 24.44 g of sodium hydroxide was added in the first suspension preparation, 47.38 g of acrylic acid was added in the second suspension preparation, 25.16 g of acrylamide was added in the third suspension preparation, and acrylonitrile was added in the fourth suspension preparation. The solids content of the binder material was 9.10 wt %. The components and their proportions of the copolymer binder of Comparative Example 11 are shown in Table 3 below. B) Preparation of the positive electrode

[0332] The cathode was prepared by the method described in Example 1, except that 15.02 g of diwater was added in preparing the first suspension and 21.98 g of the binder material (9.10 wt % solids) was added in preparing the second suspension of the cathode slurry. The concentration of the lithium compound in the cathode slurry was 1.0 M, the solubility ratio of the lithium compound in the cathode slurry was 18.9, and the solids content of the cathode slurry was 65.00%. Preparation of binder materials for Comparative Examples 12-13

[0333] The binder material is prepared by the method described in Example 1. Preparation of the positive electrode of Comparative Example 12

[0334] The cathode was prepared by the method described in Example 1, except that 4.63 g of the lithium compound LiNO2 was added in the preparation of the first suspension of the cathode slurry. The concentration of the lithium compound in the cathode slurry was 2.5 M, and the solubility ratio of the lithium compound in the cathode slurry was 7.56. Preparation of the positive electrode of Comparative Example 13

[0335] The cathode was prepared by the method described in Example 8, except that 3.21 g of the lithium compound lithium oxalate was added in the preparation of the first suspension of the cathode slurry. The concentration of the lithium compound in the cathode slurry was 0.9 M, and the solubility ratio of the lithium compound in the cathode slurry was 0.867, which was less than 1, while the lithium ion concentration of the lithium compound in the cathode slurry was 1.8 M. Preparation of negative electrodes for Examples 2-19 and Comparative Examples 1-13

[0336] The negative electrode is prepared by the same method as described in Example 1. Coin cell assemblies of Examples 2-19 and Comparative Examples 1-13

[0337] The CR2032 coin Li cell is assembled in the same manner as described in Example 1. Electrochemical measurements of Example 2-19

[0338] Electrochemical measurements were obtained by the same method as described in Example 1. The electrochemical performance of the coin cells of Examples 2-19 was measured and is shown in Table 2 below. Electrochemical measurements of Comparative Examples 1-13

[0339] Electrochemical measurements were obtained by the same method as described in Example 1. The electrochemical performance of the coin cells of Examples 1-13 was measured and is shown in Table 3 below. [Table 1] [Table 2] [Table 3] [Table 4]

[0340] Although the invention has been described with respect to a limited number of embodiments, the particular features of one embodiment should not be attributed to other embodiments of the invention. In some embodiments, the method may include numerous steps not mentioned herein. In other embodiments, the method does not include, or is substantially free of, any steps not recited herein. Variations and modifications from the described embodiments exist. The appended claims are intended to cover all such variations and modifications as fall within the scope of the invention. The inventions described in the original claims of this application are set forth below. [1] A cathode slurry for a secondary battery comprising a cathode active material, a polymeric binder, a lithium compound, and an aqueous solvent. [2] The lithium compound has the chemical formula [ka] is a compound represented by the cation A+ is Li+, a is an integer from 1 to 10, The anion Ba is an oxidizable anion; [1] Cathode slurry. [3] The decomposition voltage of the lithium compound is from about 3.0 V to about 5.0 V. [2] Cathode slurry. [4] the concentration of the lithium compound in the slurry is from about 0.005M to 2.0M; The solubility ratio of the lithium compound is 1 or more; [2] Cathode slurry. [5] The aqueous solvent is water. [1] Cathode slurry. [6] The aqueous solution contains water as a major component and a minor component, the proportion of water in the aqueous solution is from about 51% to about 100% by weight; the minor component is selected from the group consisting of methanol, ethanol, isopropanol, n-propanol, tert-butanol, n-butanol, acetone, dimethyl ketone, methyl ethyl ketone, ethyl acetate, isopropyl acetate, butyl acetate, and combinations thereof; [1] Cathode slurry. [7] The cathode active material is Li 1+x Ni a Mn b Co c Al (1-a-b-c) O 2 , LiNi 0.33 Mn 0.33 Co 0.33 O 2 , LiNi 0.4 Mn 0.4 Co 0.2 O 2 , LiNi 0.5 Mn 0.3 Co 0.2 O 2 , LiNi 0.6 Mn 0.2 Co 0.2 O 2 , LiNi 0.7 Mn 0.15 Co 0.15 O 2 , LiNi 0.8 Mn 0.1 Co 0.1 O 2 , LiNi 0.92 Mn 0.04 Co 0.04 O 2 , LiNi 0.8 Co 0.15 Al 0.05 O 2 , LiCoO 2 , LiNiO 2 , LiMnO 2 , LiMn 2 O 4 , Li 2 MnO 3 , LiMPO4 , LiNi d Mn e O 4 and combinations thereof; wherein -0.2<=x<=0.2, 0<=a<1, 0<=b<1, 0<=c<1, a+b+c<=1, 0.1<=d<=0.0.8, 0.1<=e<=2, and M is selected from the group consisting of Fe, Co, Ni, Mn, Al, Mg, Zn, Ti, La, Ce, Sn, Zr, Ru, Si, Ge, or a combination thereof; the cathode active material is doped with a dopant selected from the group consisting of Fe, Ni, Mn, Al, Mg, Zn, Ti, La, Ce, Sn, Zr, Ru, Si, Ge, or a combination thereof; [1] Cathode slurry. [8] The cathode active material comprises a core containing a lithium transition metal oxide of [7] and a lithium transition metal oxide different from the core. 1+x NiaMn b Co c Al (1-a-b-c) O 2 , LiCoO 2 , LiNiO 2 , LiMnO 2 , LiMn 2 O 4 , Li 2 MnO 3 , LiCrO 2 , Li 4 Ti 5 O 12 , LiV 2 O 5 , LiTiS 2 , LiMoS 2 and a shell comprising a lithium transition metal oxide selected from the group consisting of: where -0.2<=x<=0.2, 0<=a<1, 0<=b<1, 0<=c<1, a+b+c<=1, and Each of the core and the shell is individually doped with a dopant selected from the group consisting of Fe, Ni, Mn, Al, Mg, Zn, Ti, La, Ce, Sn, Zr, Ru, Si, Ge, or a combination thereof; [1] Cathode slurry. [9] the percentage of cathode active material in the cathode slurry is from about 20% to about 70% by weight, based on the total weight of the cathode slurry; [1] Cathode slurry.

[10] the polymeric binder comprises structural units (a) derived from a monomer selected from the group consisting of a monomer containing a carboxylic acid group, a monomer containing a sulfonic acid group, a monomer containing a phosphonic acid group, a monomer containing a carboxylate group, a monomer containing a sulfonate group, a monomer containing a phosphonate group, and combinations thereof; [1] Cathode slurry.

[11] the proportion of structural units (a) in the polymeric binder is from about 15% to about 80% by mole, based on the total moles of monomer units in the polymeric binder;

[10] cathode slurry.

[12] The monomer containing a carboxylic acid group may be acrylic acid, methacrylic acid, crotonic acid, 2-butylcrotonic acid, cinnamic acid, maleic acid, maleic anhydride, fumaric acid, itaconic acid, itaconic anhydride, tetraconic acid, 2-ethylacrylic acid, isocrotonic acid, cis-2-pentenoic acid, trans-2-pentenoic acid, angelic acid, tiglic acid, 3,3-dimethylacrylic acid, 3-propylacrylic acid, trans-2-methyl-3-ethylacrylic acid, cis-2-methyl-3-ethylacrylic acid, 3-isopropylacrylic acid, trans-3-methyl-3-ethylacrylic acid, cis-3-methyl-3-ethylacrylic acid, 2-isopropylacrylic acid, trimethylacrylic acid, 2-methyl-3,3 -Diethylacrylic acid, 3-butylacrylic acid, 2-butylacrylic acid, 2-pentylacrylic acid, 2-methyl-2-hexenoic acid, trans-3-methyl-2-hexenoic acid, 3-methyl-3-propylacrylic acid, 2-ethyl-3-propylacrylic acid, 2,3-diethylacrylic acid, 3,3-diethylacrylic acid, 3-methyl-3-hexylacrylic acid, 3-methyl-3-tert-butylacrylic acid, 2-methyl-3-pentylacrylic acid, 3-methyl-3-pentylacrylic acid, 4-methyl-2-hexenoic acid, 4-ethyl-2-hexenoic acid, 3-methyl-2-ethyl-2-hexenoic acid, 3-tert-butylacrylic acid, 2,3-dimethyl-3-ethylacrylic acid, 3,3-dimethyl-2-ethylacrylic acid, 3-methyl-3-isopropylacrylic acid, 2-methyl-3-isopropylacrylic acid, trans-2-octenoic acid, cis-2-octenoic acid, trans-2-dectenoic acid, α-acetoxyacrylic acid, β-trans-aryloxyacrylate, α-chloro-β-E-methoxyacrylate, methylmaleic acid, dimethylmaleic acid, phenylmaleic acid, maleic bromide, chloromaleic acid, dichloromaleic acid, fluoromaleic acid, difluoromaleic acid, nonyl hydrogen maleate, decyl hydrogen maleate, dodecyl hydrogen maleate, octadecyl hydrogen maleate, fluoroalkyl hydrogen maleate, maleic anhydride, methylmaleic anhydride, dimethylmaleic anhydride, acrylic anhydride, methylacrylic anhydride, methacrolein, methacryloyl chloride, methacryloyl fluoride, methacryloyl bromide, or combinations thereof.

[10] cathode slurry.

[13] The monomer containing a carboxylate group may be an acrylate, a methacrylate, a crotonate, a 2-butylcrotonate, a cinnamate, a maleate, a maleic anhydride, a fumarate, an itaconate, an itaconate anhydride, a tetraconate, a 2-ethylacrylate, an isocrotonate, a cis-2-pentenoate, a trans-2-pentenoate, an angelate, a tiglate, a 3,3-dimethylacrylate, a 3-propylacrylate, a trans-2-methyl-3-ethylacrylate, a cis ... Acrylate, 3-isopropyl acrylate, trans-3-methyl-3-ethyl acrylate, cis-3-methyl-3-ethyl acrylate, 2-isopropyl acrylate, trimethyl acrylate, 2-methyl-3,3-diethyl acrylate, 3-butyl acrylate, 2-butyl acrylate, 2-pentyl acrylate, 2-methyl-2-hexenoate, trans-3-methyl-2-hexenoate, 3-methyl-3-propyl acrylate, 2-ethyl-3-propyl acrylate, 2,3-diethyl acrylate Acrylate, 3,3-diethylacrylate, 3-methyl-3-hexylacrylate, 3-methyl-3-tert-butylacrylate, 2-methyl-3-pentylacrylate, 3-methyl-3-pentylacrylate, 4-methyl-2-hexenoate, 4-ethyl-2-hexenoate, 3-methyl-2-ethyl-2-hexenoate, 3-tert-butylacrylate, 2,3-dimethyl-3-ethylacrylate, 3,3-dimethyl-2-ethylacrylate, 3-methyl-3-isopropylacrylate , 2-methyl-3-isopropylacrylate, trans-2-octenoate, cis-2-octenoate, trans-2-dectenoate, α-acetoxyacrylate, β-trans-aryloxyacrylate, α-chloro-β-E-methoxyacrylate, methylmaleate, dimethylmaleate, phenylmaleate, bromomaleate, chloromaleate, dichloromaleate, fluoromaleate, difluoromaleate, or a combination thereof;

[10] cathode slurry.

[14] The sulfonic acid group-containing monomer is selected from vinyl sulfonic acid, methyl vinyl sulfonic acid, aryl vinyl sulfonic acid, aryl sulfonic acid, methyl aryl sulfonic acid, styrene sulfonic acid, 2-sulfoethyl methacrylic acid, 2-methylprop-2-ene-1-sulfonic acid, 2-acrylamido-2-methyl-1-propanesulfonic acid, 3-allyloxy-2-hydroxy-1-propanesulfonic acid, or a combination thereof;

[10] cathode slurry.

[15] the sulfonate group-containing monomer is selected from the group consisting of vinyl sulfonate, methyl vinyl sulfonate, aryl vinyl sulfonate, aryl sulfonate, methyl aryl sulfonate, styrene sulfonate, 2-sulfoethyl methacrylate, 2-methyprop-2-ene-1-sulfonate, 2-acrylamido-2-methyl-1-propanesulfonate, 3-allyloxy-2-hydroxy-1-propanesulfonate, or a combination thereof;

[10] cathode slurry.

[16] The monomer containing a phosphonic acid group is selected from vinyl phosphonic acid, aryl phosphonic acid, vinylbenzyl phosphonic acid, acrylamido alkyl phosphonic acid, methacrylamide alkyl phosphonic acid, acrylamido alkyl diphosphonic acid, acryloyl phosphonic acid, 2-methacryloyloxyethyl phosphonic acid, bis(2-methacryloyloxyethyl) phosphonic acid, ethylene 2-methacryloyloxyethyl phosphonic acid, ethyl-methacryloyloxyethyl phosphonic acid, or combinations thereof;

[10] cathode slurry.

[17] The phosphonate group-containing monomer is selected from the group consisting of vinyl phosphonates, salts of aryl phosphonic acids, salts of vinylbenzyl phosphonic acids, salts of acrylamidoalkyl phosphonic acids, salts of methacrylamidoalkyl phosphonic acids, salts of acrylamidoalkyl diphosphonic acids, salts of acryloyl phosphonic acids, salts of 2-methacryloyloxyethyl phosphonic acids, salts of bis(2-methacryloyloxyethyl) phosphonic acids, salts of ethylene 2-methacryloyloxyethyl phosphonic acids, salts of ethyl-methacryloyloxyethyl phosphonic acids, or combinations thereof.

[10] cathode slurry.

[18] The polymeric binder further comprises a structural unit (b), The structural unit (b) is derived from a monomer selected from the group consisting of a monomer containing an amide group, a monomer containing a hydroxyl group, and a combination thereof.

[10] cathode slurry.

[19] the proportion of structural units (b) in the polymeric binder is from about 5% to about 35% by mole, based on the total moles of monomer units in the polymeric binder;

[10] cathode slurry.

[20] The monomer containing an amide group is, for example, acrylamide, methacrylamide, N-methylmethacrylamide, N-ethylmethacrylamide, Nn-propylmethacrylamide, N-isopropylmethacrylamide, isopropylacrylamide, Nn-butylmethacrylamide, N-isobutylmethacrylamide, N,N-dimethylacrylamide, N,N-dimethylmethacrylamide, N,N-diethylacrylamide, N,N-diethylmethacrylamide, N-methylolmethacrylamide, N-(methoxymethyl)methacrylamide, N-(ethoxymethyl)methacrylamide, N-(propoxymethyl)methacrylamide, acrylamide, N-(butoxymethyl)methacrylamide, N,N-dimethylmethacrylamide, N,N-dimethylaminopropylmethacrylamide, N,N-dimethylaminoethylmethacrylamide, N,N-dimethylolmethacrylamide, diacetone methacrylamide, diacetone acrylamide, methacryloylmorpholine, N-hydroxylmethacrylamide, N-methoxymethylacrylamide, N-methoxymethylmethacrylamide, N,N'-methylene-bis-acrylamide (MBA), N-hydroxymethylacrylamide, or combinations thereof;

[18] cathode slurry.

[21] The polymeric binder further comprises a structural unit (c), The structural unit (c) is selected from the group consisting of a monomer containing a nitrile group, a monomer containing an ester group, a monomer containing an epoxy group, a monomer containing fluorine, and combinations thereof.

[10] or

[18] cathode slurry.

[22] the proportion of structural units (c) in the polymeric binder is from about 15% to about 75% by mole, based on the total moles of monomer units in the polymeric binder;

[21] cathode slurry.

[23] The nitrile group-containing monomer is selected from the group consisting of acrylonitrile, α-halogenoacrylonitrile, α-alkylacrylonitrile, α-chloroacrylonitrile, α-bromoacrylonitrile, α-fluoroacrylonitrile, methacrylonitrile, α-ethylacrylonitrile, α-isopropylacrylonitrile, α-n-hexylacrylonitrile, α-methyoxyacrylonitrile, 3-methyoxyacrylonitrile, 3-ethyoxyacrylonitrile, α-acetoxyacrylonitrile, α-phenylacrylonitrile, α-tolylacrylonitrile, α-(methoxyphenyl)acrylonitrile, α-(chlorophenyl)acrylonitrile, α-(cyanophenyl)acrylonitrile, vinylidene cyanide, or a combination thereof;

[21] cathode slurry.

[24] The proportion of the polymer binder in the cathode slurry is from about 0.1% to about 10% by weight, based on the total weight of the cathode slurry. [1] Cathode slurry.

[25] further comprising a conductive agent selected from the group consisting of carbon, carbon black, graphite, expanded graphite, graphene, graphene nanoplatelets, carbon fiber, carbon nanofiber, graphitized carbon flakes, carbon tubes, carbon nanotubes, activated carbon, Super P, 0D KS6, 1D vapor grown carbon fiber (VGCF), mesoporous carbon, and combinations thereof; [1] Cathode slurry.

[26] The proportion of the conductive agent in the cathode slurry is from about 0.5% to about 5% based on the total weight of the cathode slurry.

[25] cathode slurry.

[27] The solids content of the cathode slurry is from 40% to 80%. [1] Cathode slurry.

[28] a cathode active material, a polymeric binder, and a lithium compound; The lithium compound has the chemical formula

change

[29] The decomposition voltage of the lithium compound is about 3.0 V to about 5.0 V.

[28] cathode.

[30] the lithium compound is attached to the surface of the particles of the cathode active material; the ratio of the average cathode active material diameter to the average lithium compound particle length is from 100:1 to 1:1;

[28] cathode.

Claims

1. A cathode slurry for a secondary battery comprising a cathode active material, a polymeric binder, a lithium compound, and an aqueous solvent, wherein the binder is a water-compatible copolymer binder and the lithium compound has a solubility ratio of 1 or greater; The lithium compound has the chemical formula 【Chemistry 1】 is a compound represented by The cation A ＋ Li ＋ and a is an integer from 1 to 10; The anion B ａ－ is an oxidizable anion, The decomposition voltage of the lithium compound is from 3.0 V to 5.0 V; the concentration of the lithium compound in the slurry is from 0.005 M to 2.0 M; the polymeric binder comprises structural units (a) derived from monomers selected from the group consisting of monomers containing a carboxylic acid group, monomers containing a sulfonic acid group, monomers containing a phosphonic acid group, monomers containing a carboxylate group, monomers containing a sulfonate group, monomers containing a phosphonate group, and combinations thereof; the proportion of structural units (a) in the polymeric binder is from 15% to 80% by mole, based on the total moles of monomer units in the polymeric binder; the polymeric binder further comprises structural units (b), the structural units (b) being derived from monomers selected from the group consisting of monomers containing an amide group, monomers containing a hydroxyl group, and combinations thereof; the proportion of structural units (b) in the polymeric binder is from 5% to 35% by mole, based on the total moles of monomer units in the polymeric binder; further comprising a structural unit (c), wherein the structural unit (c) is selected from the group consisting of a monomer containing a nitrile group, a monomer containing an ester group, a monomer containing an epoxy group, a monomer containing fluorine, and combinations thereof; the proportion of the structural unit (c) in the polymeric binder is from 15% to 75% by mole, based on the total moles of monomer units in the polymeric binder; and the lithium compound is selected from the group consisting of lithium azide, lithium nitrite, lithium chloride, lithium delta, lithium squarate, lithium croconic acid, lithium rhodizonate, lithium ketomalonate, lithium diketosuccinate, lithium hydrazide, lithium fluoride, lithium bromide, lithium iodide, lithium sulfite, lithium selenite, lithium nitrate, lithium acetate, lithium 3,4-dihydroxybenzoate, lithium 3,4-dihydroxybutyrate, lithium formate, lithium dodecyl sulfate, lithium succinate, lithium citrate, and combinations thereof. Cathode slurry.

2. The aqueous solvent is water. The cathode slurry of claim 1.

3. The aqueous solvent comprises water as a major component and a minor component, The proportion of water in the aqueous solvent is from 51% to 100% by weight; the minor component is selected from the group consisting of methanol, ethanol, isopropanol, n-propanol, tertiary butanol, n-butanol, acetone, dimethyl ketone, methyl ethyl ketone, ethyl acetate, isopropyl acetate, butyl acetate, and combinations thereof; The cathode slurry of claim 1.

4. The cathode active material is Li １＋ｘ Ni ａ Mn ｂ Co ｃ Al （１－ａ－ｂ－ｃ） O ２ , LiNi ０．３３ Mn ０．３３ Co ０．３３ O ２ , LiNi ０．４ Mn ０．４ Co ０．２ O ２ , LiNi ０．５ Mn ０．３ Co ０．２ O ２ , LiNi ０．６ Mn ０．２ Co ０．２ O ２ , LiNi ０．７ Mn ０．１５ Co ０．１５ O ２ , LiNi ０．８ Mn ０．１ Co ０．１ O ２ , LiNi ０．９２ Mn ０．０４ Co ０．０４ O ２ , LiNi ０．８ Co ０．１５ Al ０．０５ O ２ , LiCoO ２ , LiNiO ２ , LiMnO ２ , LiMn ２ O ４ , Li ２ MnO ３ , LiMPO ４ , LiNi ｄ Mn ｅ O ４ and combinations thereof; wherein -0.2<=x<=0.2, 0<=a<1, 0<=b<1, 0<=c<1, a+b+c<=1, 0.1<=d<=0.0.8, 0.1<=e<=2, and 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; the cathode active material is doped with a dopant selected from the group consisting of Fe, Ni, Mn, Al, Mg, Zn, Ti, La, Ce, Sn, Zr, Ru, Si, Ge, or a combination thereof; The cathode slurry of claim 1.

5. The cathode active material is a core containing the cathode active material of claim 4, and different from the core, Li １＋ｘ Ni ａ Mn ｂ Co ｃ Al （１－ａ－ｂ－ｃ） O ２ , LiCoO ２ , LiNiO ２ , LiMnO ２ , LiMn ２ O ４ , Li ２ MnO ３ , LiCrO ２ , Li ４ Ti ５ O １２ , LiV ２ O ５ , LiTiS ２ , LiMoS ２ and a shell comprising a lithium transition metal oxide selected from the group consisting of: where −0.2<=x<=0.2, 0<=a<1, 0<=b<1, 0<=c<1, a+b+c<=1, Each of the core and the shell is individually doped with a dopant selected from the group consisting of Fe, Ni, Mn, Al, Mg, Zn, Ti, La, Ce, Sn, Zr, Ru, Si, Ge, and combinations thereof; The cathode slurry of claim 1.

6. the proportion of the cathode active material in the cathode slurry is from 20% to 70% by weight, based on the total weight of the cathode slurry; The cathode slurry of claim 1.

7. The monomer containing a carboxylic acid group includes acrylic acid, methacrylic acid, crotonic acid, 2-butylcrotonic acid, cinnamic acid, maleic acid, maleic anhydride, fumaric acid, itaconic acid, itaconic anhydride, tetraconic acid, 2-ethylacrylic acid, isocrotonic acid, cis-2-pentenoic acid, trans-2-pentenoic acid, angelic acid, tiglic acid, 3,3-dimethylacrylic acid, 3-propylacrylic acid, trans-2-methyl-3-ethylacrylic acid, cis-2-methyl-3-ethylacrylic acid, 3-Isopropylacrylic acid, trans-3-methyl-3-ethylacrylic acid, cis-3-methyl-3-ethylacrylic acid, 2-isopropylacrylic acid, trimethylacrylic acid, 2-methyl-3,3-diethylacrylic acid, 3-butylacrylic acid, 2-butylacrylic acid, 2-pentylacrylic acid, 2-methyl-2-hexenoic acid, trans-3-methyl-2-hexenoic acid, 3-methyl-3-propylacrylic acid, 2-ethyl-3-propylacrylic acid, 2,3-diethylacrylic acid , 3,3-diethylacrylic acid, 3-methyl-3-hexylacrylic acid, 3-methyl-3-tert-butylacrylic acid, 2-methyl-3-pentylacrylic acid, 3-methyl-3-pentylacrylic acid, 4-methyl-2-hexenoic acid, 4-ethyl-2-hexenoic acid, 3-methyl-2-ethyl-2-hexenoic acid, 3-tert-butylacrylic acid, 2,3-dimethyl-3-ethylacrylic acid, 3,3-dimethyl-2-ethylacrylic acid, 3-methyl-3-isopropylacrylic acid, selected from the group consisting of 2-methyl-3-isopropylacrylic acid, trans-2-octenoic acid, cis-2-octenoic acid, trans-2-dectenoic acid, α-acetoxyacrylic acid, β-trans-aryloxyacrylates, α-chloro-β-E-methoxyacrylates, methylmaleic acid, dimethylmaleic acid, phenylmaleic acid, bromomaleic acid, chloromaleic acid, dichloromaleic acid, fluoromaleic acid, difluoromaleic acid, and combinations thereof; The cathode slurry of claim 1.

8. The monomer containing a carboxylate group may be an acrylate, a methacrylate, a crotonate, a 2-butylcrotonate, a cinnamate, a maleate, a fumarate, an itaconate, a tetraconate, a 2-ethylacrylate, an isocrotonate, a cis-2-pentenoate, a trans-2-pentenoate, an angelate, a tiglate, a 3,3-dimethylacrylate, a 3-propylacrylate, a trans-2-methyl-3-ethylacrylate, a cis-2-methyl-3-ethylacrylate, a 3-isopropylacrylate, a methyl ... Acrylates, trans-3-methyl-3-ethyl acrylate, cis-3-methyl-3-ethyl acrylate, 2-isopropyl acrylate, trimethyl acrylate, 2-methyl-3,3-diethyl acrylate, 3-butyl acrylate, 2-butyl acrylate, 2-pentyl acrylate, 2-methyl-2-hexenoate, trans-3-methyl-2-hexenoate, 3-methyl-3-propyl acrylate, 2-ethyl-3-propyl acrylate, 2,3-diethyl acrylate, 3,3 -diethyl acrylate, 3-methyl-3-hexyl acrylate, 3-methyl-3-tert-butyl acrylate, 2-methyl-3-pentyl acrylate, 3-methyl-3-pentyl acrylate, 4-methyl-2-hexenoate, 4-ethyl-2-hexenoate, 3-methyl-2-ethyl-2-hexenoate, 3-tert-butyl acrylate, 2,3-dimethyl-3-ethyl acrylate, 3,3-dimethyl-2-ethyl acrylate, 3-methyl-3-isopropyl acrylate, 2- selected from the group consisting of methyl-3-isopropylacrylate, trans-2-octenoate, cis-2-octenoate, trans-2-dectenoate, α-acetoxyacrylate, β-trans-aryloxyacrylate, α-chloro-β-E-methoxyacrylate, methylmaleate, dimethylmaleate, phenylmaleate, bromomaleate, chloromaleate, dichloromaleate, fluoromaleate, difluoromaleate, and combinations thereof; The cathode slurry of claim 1.

9. The sulfonic acid group-containing monomer is selected from vinyl sulfonic acid, methyl vinyl sulfonic acid, aryl vinyl sulfonic acid, aryl sulfonic acid, methylene aryl sulfonic acid, styrene sulfonic acid, 2-sulfoethyl methacrylic acid, 2-methylprop-2-ene-1-sulfonic acid, 2-acrylamido-2-methyl-1-propanesulfonic acid, 3-allyloxy-2-hydroxy-1-propanesulfonic acid, and combinations thereof. The cathode slurry of claim 1.

10. the sulfonate group-containing monomer is selected from the group consisting of vinyl sulfonate, methyl vinyl sulfonate, aryl vinyl sulfonate, aryl sulfonate, methyl aryl sulfonate, styrene sulfonate, 2-sulfoethyl methacrylate, 2-methyprop-2-ene-1-sulfonate, 2-acrylamido-2-methyl-1-propanesulfonate, 3-allyloxy-2-hydroxy-1-propanesulfonate, and combinations thereof; The cathode slurry of claim 1.

11. The monomer containing a phosphonic acid group is selected from vinyl phosphonic acid, aryl phosphonic acid, vinylbenzyl phosphonic acid, acrylamido alkyl phosphonic acid, methacrylamide alkyl phosphonic acid, acrylamido alkyl diphosphonic acid, acryloyl phosphonic acid, 2-methacryloyloxyethyl phosphonic acid, bis(2-methacryloyloxyethyl) phosphonic acid, ethylene 2-methacryloyloxyethyl phosphonic acid, ethyl-methacryloyloxyethyl phosphonic acid, and combinations thereof. The cathode slurry of claim 1.

12. The monomer containing a phosphonate group is selected from the group consisting of vinyl phosphonates, salts of aryl phosphonic acids, salts of vinylbenzyl phosphonic acids, salts of acrylamidoalkyl phosphonic acids, salts of methacrylamidoalkyl phosphonic acids, salts of acrylamidoalkyl diphosphonic acids, salts of acryloyl phosphonic acids, salts of 2-methacryloyloxyethyl phosphonic acids, salts of bis(2-methacryloyloxyethyl) phosphonic acids, salts of ethylene 2-methacryloyloxyethyl phosphonic acids, salts of ethyl-methacryloyloxyethyl phosphonic acids, and combinations thereof. The cathode slurry of claim 1.

13. The monomer containing an amide group includes acrylamide, methacrylamide, N-methylmethacrylamide, N-ethylmethacrylamide, N-n-propylmethacrylamide, N-isopropylmethacrylamide, isopropylacrylamide, N-n-butylmethacrylamide, N-isobutylmethacrylamide, N,N-dimethylacrylamide, N,N-dimethylmethacrylamide, N,N-diethylacrylamide, N,N-diethylmethacrylamide, N-methylolmethacrylamide, N-(methoxymethyl)methacrylamide, N-(ethoxymethyl)methacrylamide, N-methylol ... acrylamide, N-(propoxymethyl)methacrylamide, N-(butoxymethyl)methacrylamide, N,N-dimethylaminopropyl methacrylamide, N,N-dimethylaminoethyl methacrylamide, N,N-dimethylol methacrylamide, diacetone methacrylamide, diacetone acrylamide, methacryloylmorpholine, N-hydroxyl methacrylamide, N-methoxymethyl acrylamide, N,N'-methylene-bis-acrylamide, N-hydroxymethyl acrylamide, and combinations thereof; The cathode slurry of claim 1.

14. The nitrile group-containing monomer is selected from the group consisting of acrylonitrile, α-chloroacrylonitrile, α-bromoacrylonitrile, α-fluoroacrylonitrile, methacrylonitrile, α-ethylacrylonitrile, α-isopropylacrylonitrile, α-n-hexylacrylonitrile, α-methyoxyacrylonitrile, 3-methyoxyacrylonitrile, 3-ethyoxyacrylonitrile, α-acetoxyacrylonitrile, α-phenylacrylonitrile, α-tolylacrylonitrile, α-(methoxyphenyl)acrylonitrile, α-(chlorophenyl)acrylonitrile, α-(cyanophenyl)acrylonitrile, vinylidene cyanide, and combinations thereof. The cathode slurry of claim 1.

15. the proportion of polymeric binder in the cathode slurry is from 0.1% to 10% by weight, based on the total weight of the cathode slurry; The cathode slurry of claim 1.

16. further comprising a conductive agent selected from the group consisting of carbon, carbon black, graphite, expanded graphite, graphene, graphene nanoplatelets, carbon fiber, carbon nanofiber, graphitized carbon flakes, carbon tubes, carbon nanotubes, activated carbon, Super P, 0-dimensional KS6, 1-dimensional vapor grown carbon fiber, mesoporous carbon, and combinations thereof; The cathode slurry of claim 1.

17. The proportion of the conductive agent in the cathode slurry is from 0.5% to 5% by weight, based on the total weight of the cathode slurry. The cathode slurry of claim 16.

18. The solids content of the cathode slurry is from 40% to 80%. The cathode slurry of claim 1.

19. The nitrile group-containing monomer is selected from the group consisting of α-halogenoacrylonitrile, α-alkylacrylonitrile, or a combination thereof. The cathode slurry of claim 1.

20. A cathode for a secondary battery comprising a cathode active material, a polymeric binder, and a lithium compound, wherein the binder is a water-compatible copolymer binder and the lithium compound has a solubility ratio of 1 or greater; The lithium compound has the chemical formula 【Chemistry 2】 is a compound represented by The cation A ＋ Li ＋ and a is an integer from 1 to 10; The anion B ａ－ is an oxidizable anion, The decomposition voltage of the lithium compound is 3.0 V to 5.0 V, the proportion of the lithium compound is less than 6% by weight based on the total weight of the electrode layer of the cathode, the polymer binder includes structural units (a) derived from a monomer selected from the group consisting of a monomer containing a carboxylic acid group, a monomer containing a sulfonic acid group, a monomer containing a phosphonic acid group, a monomer containing a carboxylate group, a monomer containing a sulfonate group, a monomer containing a phosphonate group, and combinations thereof, and the proportion of the structural units (a) in the polymer binder is In the case of the polymeric binder, the proportion of structural units (b) is from 15% to 80% by mole based on the total moles of monomer units in the polymeric binder, the polymeric binder further comprises structural units (b), the structural units (b) being derived from a monomer selected from the group consisting of a monomer containing an amide group, a monomer containing a hydroxyl group, and combinations thereof, the proportion of structural units (b) in the polymeric binder is from 5% to 35% by mole based on the total moles of monomer units in the polymeric binder, and the polymeric binder further comprises structural units (b). The polymer binder further comprises a monomer (c), wherein the structural unit (c) is selected from the group consisting of a monomer containing a nitrile group, a monomer containing an ester group, a monomer containing an epoxy group, a monomer containing fluorine, and a combination thereof, and the proportion of the structural unit (c) in the polymer binder is 15% to 75% by mole based on the total moles of monomer units in the polymer binder, and the lithium compound is selected from the group consisting of lithium azide, lithium nitrite, lithium chloride, lithium delta, lithium squarate, lithium croconic acid, and lithium rhodizonate. the lithium compound is selected from the group consisting of lithium fluoride, lithium ketomalonate, lithium diketosuccinate, lithium hydrazide, lithium fluoride, lithium bromide, lithium iodide, lithium sulfite, lithium selenite, lithium nitrate, lithium acetate, lithium 3,4-dihydroxybenzoate, lithium 3,4-dihydroxybutyrate, lithium formate, lithium dodecyl sulfate, lithium succinate, lithium citrate, and combinations thereof, wherein the ratio of the average diameter of the cathode active material to the average length of the lithium compound particles is from 100:1 to 1:1; Cathode for secondary batteries.

21. the lithium compound is attached to the surface of the particles of the cathode active material; 21. The cathode of claim 20.

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