Dispersing agent and preparation method thereof, positive electrode slurry, positive electrode plate and preparation method thereof, battery monomer, battery and electric device

Abstract

The invention provides a dispersing agent and a preparation method thereof, positive electrode slurry, a positive electrode plate and a preparation method thereof, a battery monomer, a battery and an electric device, the positive electrode dispersing agent has a structure as shown in a formula (I), and R1, R2, R3, x and y are respectively defined in the description. # imgabs0 #

Description

Dispersant and preparation method thereof, positive electrode slurry, positive electrode sheet and preparation method thereof, battery cell, battery and electrical device Technical Field

[0001] The present application relates to a dispersant and a preparation method thereof, a positive electrode slurry, a positive electrode plate and a preparation method thereof, a battery cell, a battery and an electrical device. Background Art

[0002] In recent years, batteries have been widely used in energy storage power systems such as hydropower, thermal power, wind power, and solar power stations, as well as in power tools, electric bicycles, electric motorcycles, electric vehicles, military equipment, aerospace, and other fields. With the application and promotion of batteries, the requirements for battery cycle performance and dynamic performance are becoming increasingly higher. At present, when preparing positive electrode sheets, there is a problem of agglomeration of positive electrode conductive agents, which will affect the preparation and performance of batteries. The above statements are only used to provide background technical information related to this application and do not necessarily constitute prior art.

[0003] Summary of the Invention

[0004] The present application provides a dispersant and a preparation method thereof, a positive electrode slurry, a positive electrode plate and a preparation method thereof, a battery cell, a battery and an electrical device, which can reduce the agglomeration of the positive electrode conductive agent and enable the battery to have high energy density, low impedance and good electrochemical performance.

[0005] In a first aspect, the present application provides a dispersant having a structure shown in formula (I), wherein R1 represents the residue of an aliphatic, alicyclic and / or aromatic diisocyanate, R2 represents the residue of an aliphatic diol, R3 represents a C2-C8 alkylene group, y represents an integer of 5-60, and the number average molecular weight of the dispersant is 10,000-60,000.

[0006] The dispersant provided in the embodiments of the present application has good dispersibility and can effectively reduce the agglomeration of the positive electrode conductive agent when added in a small amount, and can also reduce the resistance of the positive electrode sheet, thereby enabling the battery to have high energy density, low impedance and good electrochemical performance.

[0007] In any embodiment, R1 includes at least one of the first group, the second group, the third group, and the fourth group.

[0008] In any embodiment, the first group includes a C2-C10 straight chain alkylene group, and optionally includes a C2-C6 straight chain alkylene group.

[0009] In any embodiment, the second group comprises

[0010] R 11 、R12 、R 13 、R 14 Each independently includes a hydrogen atom, a C1-C12 chain alkyl group, a C1-C12 oxygen chain alkyl group, a C1-C12 sulfur chain alkyl group, a C3-C12 chain alkenyl group, a 3-6 membered N-containing heterocyclic group, a 3-6 membered O-containing heterocyclic group, and a group represented by A1 to A6, and R 11 、R 12 、R 13 、R 14 Not all hydrogen atoms.

[0011] Optionally, R 11 、R 12 、R 13 、R 14 Each independently includes a hydrogen atom, a C2-C8 chain alkyl group, a C3-C8 oxo chain alkyl group, a C3-C8 thio chain alkyl group, a C4-C8 chain alkenyl group, and the groups represented by A1 to A6, and R 11 、R 12 、R 13 、R 14 At least one of them includes C3-C8 oxygen heterochain alkyl, C3-C8 sulfur heterochain alkyl, and the group represented by A1 to A6.

[0012] R 15 Each independently includes a C1-C8 chain alkyl group, and optionally includes a C1-C3 chain alkyl group; R 16 Each independently includes a C1-C8 chain alkylene group, and optionally includes a C1-C3 chain alkylene group.

[0013] In any embodiment, the third group includes groups shown in B1 to B8,

[0014] Optionally, the third group includes the following groups:

[0015] In any embodiment, the fourth group includes groups shown by D1 to D7,

[0016] Optionally, the fourth group includes the following groups:

[0017] In any embodiment, R a Each independently includes one or more of cyano, amino, sulfonic acid and its salts, sulfonate, phosphate, C1-C8 oxo-chain alkyl, and C1-C8 chain alkyl; R bEach independently includes one or more of a cyano group, an amino group, a sulfonic acid group and its salts, a sulfonate group, a phosphate group, a C1-C8 oxo-chain alkyl group, and a C1-C8 chain alkyl group; p each independently represents an integer from 0 to 4, optionally 0 or 1; q each independently represents an integer from 0 to 6, optionally 0 or 1.

[0018] In any embodiment, R2 includes the following groups:

[0019] R 21 、R 22 、R 23 、R 24 、R 25 、R 26 Each independently includes a hydrogen atom, a C1-C12 chain alkyl group, and a group represented by E1 to E4, and R 21 、R 22 、R 23 、R 24 、R 25 、R 26 are not hydrogen atoms at the same time. 21 、R 22 、R 23 、R 24 、R 25 、R 26 Each independently includes a hydrogen atom, a C1-C12 chain alkyl group, and a group represented by E1 to E4, and R 21 、R 22 、R 23 、R 24 、R 25 、R 26 At least one of the groups includes groups shown by E1 to E4.

[0020] R 27 Each independently includes a C1-C8 chain alkyl group, and optionally includes a C1-C4 chain alkyl group; R 28 Each independently includes a C1-C8 chain alkylene group, and optionally includes a C1-C3 chain alkylene group.

[0021] In any embodiment, R3 includes the following groups:

[0022] In any embodiment, # indicates a connection location.

[0023] In any embodiment, R1 includes at least one of the second group and the third group.

[0024] The second group includes

[0025] R 11 、R 12 、R 13 、R 14 Each independently includes a hydrogen atom, a C2-C8 chain alkyl group, a C3-C8 oxygen chain alkyl group, a C3-C8 sulfur chain alkyl group, and the groups represented by A4 to A6, and R 11 、R 12 、R 13 、R 14 At least one of the group A4 to A6 is included;

[0026] R 15 Each independently includes C1-C3 chain alkyl; R 16 Each independently includes a C1-C3 chain alkylene group.

[0027] The third group includes the groups shown in B1 to B3,

[0028] R a They independently include one or more of cyano, amino, sulfonic acid and its salts, sulfonate, phosphate, C1-C3 oxo-chain alkyl, and C1-C3 chain alkyl, and p is independently 0 or 1.

[0029] Optionally, the third group includes the following groups:

[0030] And R2 includes the following groups:

[0031] R 21 、R 22 、R 23 、R 24 、R 25 、R 26 Each independently includes a hydrogen atom, a C1-C12 chain alkyl group, and a group represented by E1 to E4, and R 21 、R 22 、R 23 、R 24 、R 25 、R 26 Not all hydrogen atoms at the same time;

[0032] R 27 Each independently includes a C1-C4 chain alkyl group; R 28 Each independently includes a C1-C3 chain alkylene group.

[0033] When R1 and R2 are within the above ranges, the dispersant has a benzene ring structure and / or long side chains, which can create a certain degree of steric hindrance, thereby achieving better dispersibility and reducing agglomeration of the positive electrode conductive agent, reducing the resistance of the positive electrode sheet, and further reducing the impedance of the battery and improving the interfacial performance of the electrode assembly, thereby further improving the interfacial dynamics and cycle performance of the battery. Furthermore, the side chains of the dispersant also contain functional groups such as carboxylate, sulfonate, and sulfinate groups, thereby achieving a better dispersion effect and, with a relatively small addition amount, reducing agglomeration of the positive electrode conductive agent and lowering the resistance of the positive electrode sheet.

[0034] In any embodiment, R1 includes at least one of the second group and the third group.

[0035] The second group includes

[0036] R 11 、R 12 、R 13 、R 14 Each independently includes a hydrogen atom, a C2-C8 chain alkyl group, a C3-C8 oxygen chain alkyl group, a C3-C8 sulfur chain alkyl group, and the groups represented by A4 to A6, and R 11 、R 12 、R 13 、R 14 At least one of the group A4 to A6 is included;

[0037] R 15 Each independently includes C1-C3 chain alkyl; R 16 Each independently includes a C1-C3 chain alkylene group.

[0038] The third group includes the groups shown in B1 to B3,

[0039] R a They independently include one or more of cyano, amino, sulfonic acid and its salts, sulfonate, phosphate, C1-C3 oxo-chain alkyl, and C1-C3 chain alkyl, and p is independently 0 or 1.

[0040] Optionally, the third group includes the following groups:

[0041] And R2 includes the following groups:

[0042] R 21 、R 22 、R 23 、R 24、R 25 、R 26 Each independently includes a hydrogen atom, a C1-C12 chain alkyl group, and a group represented by E1 to E4, and R 21 、R 22 、R 23 、R 24 、R 25 、R 26 At least one of includes the groups shown by E1 to E4,

[0043] R 27 Each independently includes a C1-C4 chain alkyl group; R 28 Each independently includes a C1-C3 chain alkylene group.

[0044] When R1 and R2 are within the above ranges, the dispersant has a relatively long side chain, which can generate a certain amount of steric hindrance, thereby achieving better dispersibility and reducing the agglomeration of the positive electrode conductive agent, reducing the resistance of the positive electrode sheet, and further reducing the impedance of the battery and improving the interfacial performance of the electrode assembly, thereby further improving the interfacial dynamics and cycle performance of the battery. Furthermore, the side chain groups of the dispersant also contain functional groups such as carboxylate, sulfonate, sulfinate, amide, and carbamate groups, thereby achieving a better dispersion effect, reducing the agglomeration of the positive electrode conductive agent and lowering the resistance of the positive electrode sheet even with a small addition amount.

[0045] In any embodiment, R1 includes at least one of the first group and the fourth group.

[0046] The first group includes a C2-C6 straight-chain alkylene group.

[0047] The fourth group includes groups shown by D1 to D7,

[0048] R a They independently include one or more of cyano, amino, sulfonic acid and its salts, sulfonate, phosphate, C1-C3 oxo-chain alkyl, and C1-C3 chain alkyl, and p is independently 0 or 1.

[0049] Optionally, the fourth group includes the following groups:

[0050] And R2 includes the following groups:

[0051] R 21 、R 22 、R 23 、R 24 、R 25 、R26 Each independently includes a hydrogen atom, a C1-C12 chain alkyl group, and a group represented by E1 to E4, and R 21 、R 22 、R 23 、R 24 、R 25 、R 26 At least one of includes the groups shown by E1 to E4,

[0052] R 27 Each independently includes a C1-C4 chain alkyl group; R 28 Each independently includes a C1-C3 chain alkylene group.

[0053] When R1 and R2 are within the above ranges, the dispersant has a relatively long side chain, which can generate a certain amount of steric hindrance, thereby achieving better dispersibility and reducing the agglomeration of the positive electrode conductive agent, thereby reducing the resistance of the positive electrode sheet. It can also reduce the impedance of the battery and improve the interfacial performance of the electrode assembly, thereby further improving the interfacial dynamics and cycle performance of the battery. At the same time, the side chain groups of the dispersant also contain functional groups such as amide groups and carbamate groups, thereby achieving a better dispersion effect, reducing the agglomeration of the positive electrode conductive agent and lowering the resistance of the positive electrode sheet even with a small addition amount.

[0054] In any embodiment, x represents an integer of 28 to 300, and may be an integer of 58 to 165. When x is within the above range, it can achieve a good dispersion effect and also enable the battery to have a lower impedance.

[0055] In any embodiment, y represents an integer from 15 to 40, and can be optionally an integer from 25 to 35.

[0056] In any embodiment, the number average molecular weight of the dispersant is 20000-50000, and can be optionally 20000-40000. When the number average molecular weight of the dispersant is within the above range, it can achieve a good dispersion effect and also make the battery have a lower impedance.

[0057] The second aspect of the present application provides a method for preparing a dispersant, comprising the following steps: providing a solvent, a catalyst, a diisocyanate O=C=N—R1—N=C=O, an aliphatic diol HO—R2—OH, and a polyether diol H—(O—R3) y —OH, the diisocyanate O═C═N—R1—N═C═O, the aliphatic diol HO—R2—OH, the polyether diol H—(O—R3) yThe molar ratio of —OH is x:x:1, and the definitions of R1, R2, R3, x, and y are respectively as defined in the first aspect of the present application; the solvent, the catalyst, the diisocyanate, and the aliphatic diol are added to the reactor for a stepwise polymerization reaction to obtain an intermediate; then the polyether diol is added to the reactor to allow the obtained intermediate to continue to react with the polyether diol, and a dispersant is obtained after the reaction is completed.

[0058] In any embodiment, in the step of adding the solvent, the catalyst, the diisocyanate and the aliphatic diol into a reactor for stepwise polymerization, the reaction temperature is 0-80°C.

[0059] In any embodiment, in the step of adding the solvent, the catalyst, the diisocyanate and the aliphatic diol into a reaction kettle for stepwise polymerization, the reaction time is 1-6 hours.

[0060] In any embodiment, the polyether diol is added to the reaction kettle, and the obtained intermediate and the polyether diol are allowed to react for 2-4 hours.

[0061] In any embodiment, the catalyst includes one or more of methacrylate, phosphonate, organolead, organoamine, and organotin.

[0062] In any embodiment, the weight of the catalyst is 0.3-1.0 wt %, optionally 0.4-0.6 wt %, based on the weight of the diisocyanate.

[0063] In any embodiment, the solvent includes one or more of tetrahydrofuran, N,N-dimethylacetamide, N,N-dimethylformamide, toluene, xylene, acetone, methyl ethyl ketone, cyclohexanone, and dioxane.

[0064] The third aspect of the present application provides a positive electrode slurry, comprising a solid component and a solvent, wherein the solid component comprises a positive electrode active material, a positive electrode conductor, a positive electrode binder and a dispersant, wherein the dispersant comprises the dispersant of the first aspect of the present application or a dispersant prepared by the method of the second aspect of the present application.

[0065] In any embodiment, based on the total weight of the solid component, the content of the dispersant is 0.1-0.5 wt %, optionally 0.2-0.3 wt %.

[0066] In any embodiment, the content of the positive electrode active material is 91.5-99.5 wt % based on the total weight of the solid component.

[0067] In any embodiment, the content of the positive electrode conductive agent is 0.1-4 wt % based on the total weight of the solid components.

[0068] In any embodiment, the content of the positive electrode binder is 0.1-4 wt % based on the total weight of the solid components.

[0069] In any embodiment, the solvent comprises an organic solvent, and may optionally comprise N-methylpyrrolidone.

[0070] In any embodiment, the solid content of the positive electrode slurry is 50%-75%.

[0071] The fourth aspect of the present application provides a positive electrode plate, comprising a positive electrode current collector and a positive electrode film layer arranged on at least one surface of the positive electrode current collector, wherein the positive electrode film layer comprises a positive electrode active material, a positive electrode conductor, a positive electrode binder and a dispersant, wherein the dispersant comprises the dispersant of the first aspect of the present application or a dispersant prepared by the method of the second aspect of the present application.

[0072] In any embodiment, the dispersant content is 0.1-0.5wt%, optionally 0.2-0.3wt%, based on the total weight of the positive electrode film layer. When the dispersant content is within the above range, a good dispersion effect can be achieved. Furthermore, the functional groups such as carboxylate, sulfonate, sulfinate, amide, and carbamate groups in the polymer chain of the dispersant have a strong affinity for the electrolyte, thereby increasing the electrolyte wetting ability of the positive electrode sheet, shortening the wetting time, and enabling the battery to have high energy density, as well as good dynamic performance and cycling performance.

[0073] In any embodiment, based on the total weight of the positive electrode film layer, the content of the positive electrode active material is 91.5-99.5 wt %.

[0074] In any embodiment, based on the total weight of the positive electrode film layer, the content of the positive electrode conductive agent is 0.1-4 wt %.

[0075] In any embodiment, based on the total weight of the positive electrode film layer, the content of the positive electrode binder is 0.1-4 wt %.

[0076] In any embodiment, the positive electrode active material is capable of extracting and inserting lithium ions or sodium ions.

[0077] The fifth aspect of the present application provides a method for preparing a positive electrode sheet, comprising the steps of: coating the positive electrode slurry of the third aspect of the present application on a positive electrode current collector, drying, and rolling to obtain a positive electrode sheet.

[0078] The sixth aspect of the present application provides another method for preparing a positive electrode sheet, comprising the steps of: mixing a positive electrode conductive agent, a positive electrode binder, a dispersant and a solvent to form a conductive slurry; kneading the positive electrode active material and the conductive slurry to form a mass material; extruding or hot pressing the obtained mass material to form a film; thinning the obtained film by rolling and then compounding it with a positive electrode current collector, and obtaining a positive electrode sheet after drying.

[0079] In any embodiment, the conductive paste has a solid content of 3-20%.

[0080] In any embodiment, the solid content of the agglomerated material is 70%-95%.

[0081] In a seventh aspect, the present application provides a battery cell, comprising the positive electrode sheet according to the fourth aspect of the present application, or the positive electrode sheet prepared by the method described in the fifth aspect or the sixth aspect of the present application.

[0082] In any embodiment, the battery cell comprises one or more of a lithium ion battery cell, a lithium metal battery cell, a sodium ion battery cell, and a sodium metal battery cell. In an eighth aspect, the present application provides a battery comprising the battery cell of the seventh aspect.

[0083] A ninth aspect of the present application provides an electrical device comprising the battery of the eighth aspect of the present application.

[0084] The electric device of the present application includes the battery provided by the present application, and thus has at least the same advantages as the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0085] To more clearly illustrate the technical solutions of the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments of the present application. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on the drawings without inventive effort.

[0086] FIG1 is a schematic structural diagram of a battery cell provided in some embodiments of the present application.

[0087] FIG2 is an exploded schematic diagram of a battery cell provided in some embodiments of the present application.

[0088] FIG3 is a schematic structural diagram of a battery module provided in some embodiments of the present application.

[0089] FIG4 is a schematic structural diagram of a battery pack provided in some embodiments of the present application.

[0090] FIG5 is an exploded schematic diagram of the battery pack shown in FIG4 .

[0091] FIG6 is a schematic diagram of an electrical device provided in some embodiments of the present application.

[0092] FIG7 is a cross-sectional view of the positive electrode sheet prepared in Example 4.

[0093] FIG8 is a cross-sectional view of the positive electrode sheet prepared in Comparative Example 1.

[0094] In the accompanying drawings, which are not necessarily drawn to scale, the reference numerals are as follows: 1. battery pack; 2. upper housing; 3. lower housing; 4. battery module; 5. battery cell; 51. housing; 52. electrode assembly; 53. cover plate. DETAILED DESCRIPTION

[0095] Below, with appropriate reference to the accompanying drawings, the embodiments of the dispersant and its preparation method, positive electrode slurry, positive electrode sheet and its preparation method, battery cell, battery and electrical device of the present application are specifically disclosed in detail. However, there may be cases where unnecessary detailed descriptions are omitted. For example, there are cases where detailed descriptions of well-known matters and repeated descriptions of actually the same structure are omitted. This is to avoid the following description from becoming unnecessarily lengthy and to facilitate the understanding of those skilled in the art. In addition, the drawings and the following description are provided for those skilled in the art to fully understand the present application and are not intended to limit the subject matter described in the claims.

[0096] " range " disclosed in the present application is limited in the form of lower limit and upper limit, and given range is limited by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundary of special range. The scope limited in this way can be to include end value or not include end value, and can be arbitrarily combined, that is, any lower limit can form a range with any upper limit combination. For example, if the scope of 60-120 and 80-110 is listed for specific parameters, it is understood that the scope of 60-110 and 80-120 is also expected. In addition, if the minimum range value 1 and 2 are listed, and if the maximum range value 3,4 and 5 are listed, then the following range can all be expected: 1-3, 1-4, 1-5, 2-3, 2-4 and 2-5. In this application, unless otherwise specified, the numerical range " ab " represents the abbreviation of any real number combination between a and b, wherein a and b are all real numbers. For example, a numerical range of "0-5" indicates that all real numbers between "0-5" are listed herein, and "0-5" is simply an abbreviation for these numerical combinations. Furthermore, when a parameter is expressed as an integer ≥ 2, this is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0097] Unless otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form new technical solutions, and such technical solutions should be considered to be included in the disclosure of the present application.

[0098] Unless otherwise specified, all technical features and optional technical features of this application can be combined with each other to form new technical solutions, and such technical solutions should be deemed to be included in the disclosure of this application.

[0099] Unless otherwise specified, all steps of the present application may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially. For example, the method may further include step (c), indicating that step (c) may be added to the method in any order, for example, the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b), etc.

[0100] Unless otherwise specified, the terms "include" and "comprising" used in this application may be open-ended or closed-ended. For example, "include" and "comprising" may mean that other components not listed may also be included or that only the listed components are included.

[0101] Unless otherwise specified, the term "or" is used in this application to be inclusive. For example, the phrase "A or B" means "A, B, or both A and B." More specifically, the condition "A or B" is satisfied if any of the following conditions are met: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0102] Unless otherwise specified, in this application, the terms "first", "second", "third", etc. are used to distinguish different objects rather than to describe a specific order or a primary-secondary relationship.

[0103] Unless otherwise specified, the terms used in this application have the common meanings that are commonly understood by those skilled in the art.

[0104] Unless otherwise stated, the numerical values ​​of the various parameters mentioned in this application can be measured using various test methods commonly used in the art, for example, they can be measured according to the test methods given in the examples of this application. Unless otherwise stated, the test temperature of each parameter is 25°C.

[0105] The term "chain alkyl" encompasses both straight-chain and branched alkyl groups. Examples of chain alkyl groups include, but are not limited to, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, isopentyl, and the like. In various embodiments, a C1-C12 chain alkyl group, i.e., a chain alkyl group, may contain 1-12 carbon atoms.

[0106] The term "chain alkylene" encompasses both straight-chain and branched chain alkylene groups. Examples of chain alkyl groups include, but are not limited to, methylene, ethylene, propylene, butylene, and the like. In various embodiments, a C1-C12 chain alkylene group, i.e., a chain alkylene group, may contain 1-12 carbon atoms.

[0107] The term "oxoalkyl" refers to an alkyl group containing oxygen atoms in the backbone. The number of oxygen atoms in the oxoalkyl group can be one or more. In various embodiments, the C1-C12 oxoalkyl group, i.e., the oxoalkyl group, can contain 1-12 carbon atoms.

[0108] The term "sulfur chain alkyl" refers to a chain alkyl group containing a sulfur atom in the backbone. The number of sulfur atoms in the sulfur chain alkyl group may be one or more. In various embodiments, the C1-C12 sulfur chain alkyl group, i.e., the sulfur chain alkyl group, may contain 1-12 carbon atoms.

[0109] The term "alkenyl" encompasses both straight-chain and branched alkenyl groups. Alkenyl groups may have one or more carbon-carbon double bonds. Examples of alkenyl groups include, but are not limited to, ethenyl, propenyl, allyl, and butenyl. In various embodiments, a C3-C12 alkenyl group, i.e., an alkenyl group, may contain 3-12 carbon atoms.

[0110] The term "3-6 membered N-containing heterocyclic group" means that the total number of carbon atoms and nitrogen atoms in the ring is 3-6. 3-6 membered N-containing heterocyclic groups include aliphatic heterocyclic groups and aromatic heterocyclic groups. By way of example, 3-6 membered N-containing heterocyclic groups include, but are not limited to, aziridine, azetidinyl, tetrahydropyrrolyl, piperidinyl, pyrrolyl, pyridyl, and the like.

[0111] The term "3-6 membered O-containing heterocyclic group" means that the total number of carbon atoms and O atoms in the ring is 3-6. 3-6 membered O-containing heterocyclic groups include aliphatic heterocyclic groups and aromatic heterocyclic groups. By way of example, 3-6 membered O-containing heterocyclic groups include, but are not limited to, propylene oxide, oxetane, tetrahydrofuranyl, tetrahydropyranyl, furanyl, pyranyl, and the like.

[0112] Throughout this manual, “#” indicates a link location.

[0113] Throughout the present specification, the expression "a single bond passes through a ring or a ring system" means that the single bond can be attached to any accessible position of the ring or the ring system.

[0114] Throughout this specification, substituents of compounds are disclosed in groups or ranges. It is expressly contemplated that this description includes each individual subcombination of members of these groups and ranges. For example, it is expressly contemplated that the term "C1-C6 alkyl" individually discloses C1, C2, C3, C4, C5, C6, C1-C6, C1-C5, C1-C4, C1-C3, C1-C2, C2-C6, C2-C5, C2-C4, C2-C3, C3-C6, C3-C5, C3-C4, C4-C6, C4-C5, C5-C6 alkyl. As another example, integers ranging from 3 to 10 are expressly contemplated to individually disclose 3, 4, 5, 6, 7, 8, 9, and 10. Accordingly, other groups or ranges may be expressly contemplated.

[0115] The battery mentioned in the embodiments of the present application may be a single physical module including one or more battery cells to provide higher voltage and capacity. For example, the battery mentioned in the present application may include a battery cell, a battery module, or a battery pack.

[0116] A battery cell is the smallest unit of a battery, independently capable of charging and discharging. A battery cell can be cylindrical, flat, rectangular, or in other shapes, though this is not a limitation in the present invention. Figure 1 shows a battery cell 5 with a rectangular structure as an example.

[0117] When there are multiple battery cells, the multiple battery cells are connected in series, in parallel, or in mixed series via a busbar. In some embodiments, the battery may be a battery module; when there are multiple battery cells, the multiple battery cells are arranged and fixed to form a battery module. In some embodiments, the battery may be a battery pack, which includes a housing and battery cells, with the battery cells or battery modules housed in the housing. In some embodiments, the housing may serve as part of the vehicle's chassis structure. For example, a portion of the housing may form at least a portion of the vehicle's floor, or a portion of the housing may form at least a portion of the vehicle's crossbeam or longitudinal beam.

[0118] In some embodiments, the battery may be an energy storage device, including an energy storage container, an energy storage cabinet, and the like.

[0119] The battery cells provided in the embodiments of the present application include lithium-ion battery cells, lithium metal battery cells, sodium-ion battery cells, sodium metal battery cells, etc., which are not limited in the embodiments of the present application.

[0120] A battery cell generally includes an electrode assembly and an electrolyte. The electrode assembly typically includes a positive electrode sheet, a negative electrode sheet, and a separator located between the positive and negative electrode sheets. The electrode assembly can be a wound structure or a stacked structure, which is not limited in the present embodiment.

[0121] The battery cell may also include an outer packaging, which can be used to encapsulate the electrode assembly and electrolyte. The outer packaging can be a hard shell, such as a hard plastic shell, aluminum shell, steel shell, etc. The outer packaging can also be a soft package, such as a pouch-type soft package. The soft package can be made of plastic, such as one or more of polypropylene (PP), polybutylene terephthalate (PBT), and polybutylene succinate (PBS).

[0122] In some embodiments, as shown in Figure 2, the outer packaging may include a housing 51 and a cover plate 53. The housing 51 may include a base plate and side plates connected to the base plate, which together form a receiving cavity. The housing 51 has an opening communicating with the receiving cavity, and the cover plate 53 is used to cover the opening, thereby sealing the receiving cavity. The electrode assembly 52 is enclosed in the receiving cavity. The number of electrode assemblies 52 contained in a battery cell 5 can be one or more, and can be adjusted according to needs.

[0123] In some embodiments, battery cells can be assembled into a battery module. The number of battery cells contained in a battery module can be multiple, and the specific number can be adjusted according to the application and capacity of the battery module. Figure 3 is a schematic diagram of a battery module 4 as an example. As shown in Figure 3, in the battery module 4, multiple battery cells 5 can be arranged in sequence along the length of the battery module 4. Of course, they can also be arranged in any other manner. The multiple battery cells 5 can further be fixed by fasteners.

[0124] Optionally, the battery module 4 may further include a housing having an accommodation space, and the plurality of battery cells 5 are accommodated in the accommodation space.

[0125] In some embodiments, the battery modules described above may also be assembled into a battery pack, and the number of battery modules contained in the battery pack may be adjusted according to the application and capacity of the battery pack.

[0126] Figures 4 and 5 are schematic diagrams of an exemplary battery pack 1. As shown in Figures 4 and 5, the battery pack 1 may include a housing and multiple battery modules 4 disposed within the housing. The housing comprises an upper housing 2 and a lower housing 3. The upper housing 2 covers the lower housing 3 and forms an enclosed space for accommodating the battery modules 4. The multiple battery modules 4 may be arranged in any manner within the housing.

[0127] A positive electrode sheet includes a positive current collector and a positive electrode film disposed on at least one surface of the positive current collector. The positive electrode film typically includes a positive electrode active material, a positive electrode conductor, and a positive electrode binder. Positive electrode sheets can be prepared using either a wet or dry process.

[0128] The wet process usually involves coating the positive electrode slurry on the positive electrode current collector, and then making the positive electrode sheet through processes such as drying and cold pressing. The positive electrode slurry is usually formed by dispersing the positive electrode active material, positive electrode conductive agent, positive electrode binder, etc. in a solvent and stirring them evenly. The positive electrode conductive agent usually uses nanoparticles with good conductivity, which usually have a large specific surface area. As a result, the positive electrode conductive agent is prone to self-agglomeration during the mixing process with the positive electrode active material, resulting in the positive electrode slurry having too high viscosity or too low solid content, which in turn causes coating difficulties. There is also the problem of agglomeration of the positive electrode conductive agent in the process of preparing the positive electrode sheet by the dry process, which leads to uneven dispersion of the positive electrode film layer.

[0129] The dispersibility of the positive electrode slurry and / or positive electrode film layer can affect the consistency of the battery. Adding a dispersant to the positive electrode sheet helps reduce the surface energy of the positive electrode conductive agent particles, reduces agglomeration of the positive electrode conductive agent, and improves the dispersion uniformity of the positive electrode slurry and / or positive electrode film layer. However, currently used dispersants require a large dosage to effectively reduce agglomeration of the positive electrode conductive agent, which can reduce the energy density of the battery.

[0130] In view of this, the inventors provide a new dispersant, which can effectively reduce the agglomeration of the positive electrode conductive agent with a small addition amount and without affecting the battery energy density, and can also reduce the battery impedance and improve the electrochemical performance of the battery.

[0131] The dispersant provided in the embodiments of the present application has a structure shown in formula (I).

[0132] R1 represents a residue of an aliphatic, alicyclic and / or aromatic diisocyanate, R2 represents a residue of an aliphatic diol, R3 represents a C2-C8 alkylene group, y represents an integer of 5-60, and the number average molecular weight of the dispersant is 10,000-60,000.

[0133] The dispersant can be composed of O=C=N—R1—N=C=O, HO—R2—OH, H—(O—R3) y —OH polymerization. O=C=N—R1—N=C=O represents aliphatic, alicyclic and / or aromatic diisocyanate, HO—R2—OH represents aliphatic diol, H—(O—R3) y —OH represents a polyether diol.

[0134] R1 represents the residue of an aliphatic, alicyclic and / or aromatic diisocyanate, that is, the remaining group after removing the isocyanate groups at both ends of the aliphatic, alicyclic and / or aromatic diisocyanate O=C=N-R1-N=C=O.

[0135] R2 represents the residue of an aliphatic diol, that is, the remaining group after removing the hydroxyl groups at both ends of the aliphatic diol HO—R2—OH.

[0136] The dispersant provided in the embodiments of the present application can be used in the positive electrode of a battery.

[0137] The dispersant provided in the embodiment of the present application has a relatively long molecular chain, so that it can be well adsorbed on the surface of the positive electrode conductive agent particles, change the charge distribution state on the surface of the positive electrode conductive agent particles, and form a double layer, so that electrostatic repulsion is generated between adjacent positive electrode conductive agent particles; in addition, the dispersant is adsorbed on the surface of the positive electrode conductive agent particles, and can also produce an adsorption layer of a certain thickness anchored on the surface of the positive electrode conductive agent particles. The polyether chain segment in its molecular chain can enhance the solubility of the dispersant and the solvent, so that the dispersants on adjacent positive electrode conductive agent particles repel each other due to the volume effect, thereby maintaining the stability of the system and improving the dispersion effect of the positive electrode conductive agent.

[0138] The end group of the dispersant is hydroxyl, which enables the dispersant to better react with the positive electrode binder, positive electrode conductor and positive electrode active material, thereby further improving its dispersion effect; at the same time, it can also increase the affinity between the positive electrode binder and the positive electrode active material, reduce the drying shrinkage stress, and thus improve the problem of electrode cracking.

[0139] In the dispersant provided in the examples of the present application, the number average molecular weight of the dispersant is 10,000-60,000. This can provide the dispersant with good dispersion effect, while also allowing the battery to have lower impedance, thereby enabling the battery to have good dynamic performance and cycle performance.

[0140] The inventors have found that when the number average molecular weight of the dispersant is too small, at the same addition amount, the dispersing effect of the dispersant is poor, and it cannot effectively reduce the agglomeration problem of the positive electrode conductive agent and / or the gel problem of the positive electrode slurry; when the number average molecular weight of the dispersant is too large, the viscosity of the dispersant itself will be too large, thereby greatly reducing its reaction activity and increasing the ion migration resistance, which in turn affects the kinetic performance and cycle performance of the battery.

[0141] Therefore, the dispersant provided in the embodiment of the present application has good dispersibility, and can effectively reduce the agglomeration of the positive electrode conductive agent when added in a small amount, and can also reduce the resistance of the positive electrode sheet, so that the battery can have high energy density, low impedance and good electrochemical properties. For example, the battery can have good kinetic performance and cycle performance.

[0142] In some embodiments, the number average molecular weight of the dispersant may be 20,000-50,000, and optionally 20,000-40,000. When the number average molecular weight of the dispersant is within the above range, it can achieve a good dispersion effect and also make the battery have a lower impedance.

[0143] The number average molecular weight of a dispersant has a meaning well known in the art and can be measured using instruments and methods known in the art, for example, by gel permeation chromatography (GPC).

[0144] y represents an integer from 5 to 60, for example, y can represent 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, or a range consisting of any of the above values. In some embodiments, y can represent an integer from 15 to 40, and can optionally be an integer from 25 to 35.

[0145] In some embodiments, x can represent an integer from 28 to 300. For example, x can represent 28, 45, 58, 65, 77, 88, 95, 100, 110, 125, 135, 150, 165, 180, 220, 250, 300, or any range thereof. Alternatively, x can represent an integer from 58 to 165. When x is within the above range, it can achieve a good dispersion effect and also provide a low impedance battery.

[0146] In some embodiments, R1 includes at least one of a first group, a second group, a third group, and a fourth group.

[0147] The first group includes a C2-C10 straight chain alkylene group, and optionally includes a C2-C6 straight chain alkylene group.

[0148] The second group includes

[0149] R 11 、R 12 、R 13 、R 14 Each independently includes a hydrogen atom, a C1-C12 chain alkyl group, a C1-C12 oxygen chain alkyl group, a C1-C12 sulfur chain alkyl group, a C3-C12 chain alkenyl group, a 3-6 membered N-containing heterocyclic group, a 3-6 membered O-containing heterocyclic group, and a group represented by A1 to A6, and R 11 、R 12 、R 13 、R 14 Not all hydrogen atoms.

[0150] Optionally, R 11 、R 12 、R 13 、R 14 Each independently includes a hydrogen atom, a C2-C8 chain alkyl group, a C3-C8 oxo chain alkyl group, a C3-C8 thio chain alkyl group, a C4-C8 chain alkenyl group, and the groups represented by A1 to A6, and R 11 、R 12 、 R 13 、R14 At least one of them includes C3-C8 oxygen heterochain alkyl, C3-C8 sulfur heterochain alkyl, and the group represented by A1 to A6.

[0151] R 15 Each independently includes a C1-C8 chain alkyl group, and optionally includes a C1-C3 chain alkyl group.

[0152] R 16 Each independently includes a C1-C8 chain alkylene group, and optionally includes a C1-C3 chain alkylene group.

[0153] As an example, R 11 、R 12 、R 13 、R 14They may independently include hydrogen atoms, -CH3, -CH2CH3, -(CH2)2CH3, -(CH2)3CH3, -(CH2)4CH3, -(CH2)5CH3, -(CH2)6CH3, -(CH2)7CH3, -CH2OCH3, -CH2OCH2CH3, -CH2O(CH2)2CH3, -CH2O(CH2)3CH3, -CH2O(CH2)4CH3, -CH2O(CH2)5CH3, -CH2O(CH2)6CH3, -(CH2)2O(CH2)5CH3, -(CH2)3O(CH2)4CH3, -CH2SCH3, -CH2SCH2CH3, -CH2S(CH2)2CH3, -CH2S(CH2)3CH3, -CH2S(CH2)4CH3, -CH2S(CH2)5CH3, -CH2S(CH2)6CH3, -(CH2)2S(CH2)5CH3, -(CH2)3S(CH2 )4CH3, -CH2CH=CH2, -CH2CH=CHCH3, -CH2CH=CHCH2CH3, -CH2CH2CH=CHCH2CH3, -COOCH3, -COOCH2CH3, -COO(CH2)2CH3, -COO(CH2)3CH3, -COO( CH2)4CH3, -CH2COOCH2CH3, -CH2COO(CH2)2CH3, -CH2COO(CH2)3CH3, -(CH2)2COO(CH2)3CH3, -SO3CH3, -SO3CH2CH3, -SO3(CH2)2CH3, -SO3(C H2)3CH3, -SO3(CH2)4CH3, -CH2SO3CH2CH3, -CH2SO3(CH2)2CH3, -CH2SO3(CH2)3CH3, -(CH2)2SO3CH3, -(CH2)2SO3CH2CH3, -(CH2)2SO3(CH2)2 CH3, -SO2CH3, -SO2CH2CH3, -SO2(CH2)2CH3, -SO2(CH2)3CH3, -SO2(CH2)4CH3, -CH2SO2CH2CH3, -CH2SO2(CH2)2CH3, -CH2SO2(CH2)3CH3, -(CH2)2SO2CH3, -(CH2)2SO2CH2CH3, -(CH2)2SO2(CH2)2CH3, aziridine, azetidinyl, tetrahydropyrrolyl, piperidinyl, pyrrolyl, pyridinyl, oxetane, oxetanyl, tetrahydrofuranyl, tetrahydropyranyl, furanyl, pyranyl, and the like, and R 11 、R 12 、R 13 、R 14 Not all hydrogen atoms.

[0154] The third group includes the groups shown in B1 to B8,

[0155] Optionally, the third group includes the following groups:

[0156] The fourth group includes groups shown by D1 to D7,

[0157] Optionally, the fourth group includes the following groups:

[0158] In the third and fourth groups above, R a Each independently includes one or more of cyano, amino, sulfonic acid and its salts, sulfonate, phosphate, C1-C8 oxo-chain alkyl, and C1-C8 chain alkyl; R b Each independently includes one or more of a cyano group, an amino group, a sulfonic acid group and its salts, a sulfonate group, a phosphate group, a C1-C8 oxo-chain alkyl group, and a C1-C8 chain alkyl group; p each independently represents an integer from 0 to 4, optionally 0 or 1; q each independently represents an integer from 0 to 6, optionally 0 or 1.

[0159] In some embodiments, R2 comprises the following groups:

[0160] R 21 、R 22 、R 23 、R 24 、R 25 、R 26 Each independently includes a hydrogen atom, a C1-C12 chain alkyl group, and a group represented by E1 to E4, and R 21 、R 22 、R 23 、R 24 、R 25 、R 26 Not all hydrogen atoms.

[0161] Optionally, R 21 、R 22 、R 23 、R 24 、R 25 、R 26 Each independently includes a hydrogen atom, a C1-C12 chain alkyl group, and a group represented by E1 to E4, and R 21 、R 22 、R 23 、R 24 、R 25 、R26 At least one of the groups includes groups shown by E1 to E4.

[0162] R 27 Each independently includes a C1-C8 chain alkyl group, and optionally includes a C1-C4 chain alkyl group.

[0163] R 28 Each independently includes a C1-C8 chain alkylene group, and optionally includes a C1-C3 chain alkylene group.

[0164] As an example, R 21 、R 22 、R 23 、R 24 、R 25 、R 26 may independently include hydrogen atoms, -CH3, -CH2CH3, -(CH2)2CH3-, -(CH2)3CH3, -(CH2)4CH3, -CONHCH3, -CONHCH2CH3, -CONH(CH2)2CH3, -CONH(CH2)3CH3, -CH2CONHCH2CH3, -CH2CONHCH2CH3, -CH2CONH(CH2)2CH3, -(CH2)2CONHCH2CH3, -(CH2)3CONHCH3, -CHOCONHCH3, -CHOCONHCH2CH3, and R 21 、R 22 、R 23 、R 24 、R 25 、R 26 Not all hydrogen atoms.

[0165] In some embodiments, R3 comprises the following group:

[0166] In some embodiments, R1 includes at least one of the second group and the third group.

[0167] The second group includes

[0168] R 11 、R 12 、R 13 、R 14 Each independently includes a hydrogen atom, a C2-C8 chain alkyl group, a C3-C8 oxygen chain alkyl group, a C3-C8 sulfur chain alkyl group, and the groups represented by A4 to A6, and R 11 、R 12 、R 13 、R 14At least one of the groups includes the groups represented by A4 to A6.

[0169] R 15 Each independently includes C1-C3 chain alkyl; R 16 Each independently includes a C1-C3 chain alkylene group.

[0170] The third group includes the groups shown in B1 to B3,

[0171] R a They independently include one or more of cyano, amino, sulfonic acid and its salts, sulfonate, phosphate, C1-C3 oxo-chain alkyl, and C1-C3 chain alkyl, and p is independently 0 or 1.

[0172] Optionally, the third group includes the following groups:

[0173] And R2 includes the following groups:

[0174] R 21 、R 22 、R 23 、R 24 、R 25 、R 26 Each independently includes a hydrogen atom, a C1-C12 chain alkyl group, and a group represented by E1 to E4, and R 21 、R 22 、R 23 、R 24 、R 25 、R 26 Not all hydrogen atoms.

[0175] R 27 Each independently includes a C1-C4 chain alkyl group; R 28 Each independently includes a C1-C3 chain alkylene group.

[0176] When R1 and R2 are within the above ranges, the dispersant has a benzene ring structure and / or long side chains, which can create a certain degree of steric hindrance, thereby achieving better dispersibility and reducing agglomeration of the positive electrode conductive agent, reducing the resistance of the positive electrode sheet, and further reducing the impedance of the battery and improving the interfacial performance of the electrode assembly, thereby further improving the interfacial dynamics and cycle performance of the battery. Furthermore, the side chains of the dispersant also contain functional groups such as carboxylate, sulfonate, and sulfinate groups, thereby achieving a better dispersion effect and, with a relatively small addition amount, reducing agglomeration of the positive electrode conductive agent and lowering the resistance of the positive electrode sheet.

[0177] In some embodiments, R1 includes at least one of the first group and the fourth group.

[0178] The first group includes a C2-C6 straight-chain alkylene group.

[0179] The fourth group includes groups shown by D1 to D7,

[0180] R a They independently include one or more of cyano, amino, sulfonic acid and its salts, sulfonate, phosphate, C1-C3 oxo-chain alkyl, and C1-C3 chain alkyl, and p is independently 0 or 1.

[0181] Optionally, the fourth group includes the following groups:

[0182] And R2 includes the following groups:

[0183] R 21 、R 22 、R 23 、R 24 、R 25 、R 26 Each independently includes a hydrogen atom, a C1-C12 chain alkyl group, and a group represented by E1 to E4, and R 21 、R 22 、R 23 、R 24 、R 25 、R 26 At least one of the groups includes groups shown by E1 to E4.

[0184] R 27 Each independently includes a C1-C4 chain alkyl group; R 28 Each independently includes a C1-C3 chain alkylene group.

[0185] When R1 and R2 are within the above ranges, the dispersant has a relatively long side chain, which can generate a certain amount of steric hindrance, thereby achieving better dispersibility and reducing the agglomeration of the positive electrode conductive agent, thereby reducing the resistance of the positive electrode sheet. It can also reduce the impedance of the battery and improve the interfacial performance of the electrode assembly, thereby further improving the interfacial dynamics and cycle performance of the battery. At the same time, the side chain groups of the dispersant also contain functional groups such as amide groups and carbamate groups, thereby achieving a better dispersion effect, reducing the agglomeration of the positive electrode conductive agent and lowering the resistance of the positive electrode sheet even with a small addition amount.

[0186] In some embodiments, R1 includes at least one of the second group and the third group.

[0187] The second group includes

[0188] R 11 、R 12 、R 13 、R 14 Each independently includes a hydrogen atom, a C2-C8 chain alkyl group, a C3-C8 oxygen chain alkyl group, a C3-C8 sulfur chain alkyl group, and the groups represented by A4 to A6, and R 11 、R 12 、R 13 、R 14 At least one of the groups includes the groups represented by A4 to A6.

[0189] R 15 Each independently includes C1-C3 chain alkyl; R 16 Each independently includes a C1-C3 chain alkylene group.

[0190] The third group includes the groups shown in B1 to B3,

[0191] R a They independently include one or more of cyano, amino, sulfonic acid and its salts, sulfonate, phosphate, C1-C3 oxo-chain alkyl, and C1-C3 chain alkyl, and p is independently 0 or 1.

[0192] Optionally, the third group includes the following groups:

[0193] And R2 includes the following groups:

[0194] R 21 、R 22 、R 23 、R 24 、R 25 、R 26 Each independently includes a hydrogen atom, a C1-C12 chain alkyl group, and a group represented by E1 to E4, and R 21 、R 22 、R 23 、R 24 、R 25 、R 26 At least one of the groups includes groups shown by E1 to E4.

[0195] R 27 Each independently includes a C1-C4 chain alkyl group; R 28Each independently includes a C1-C3 chain alkylene group.

[0196] When R1 and R2 are within the above ranges, the dispersant has a relatively long side chain, which can generate a certain amount of steric hindrance, thereby achieving better dispersibility and reducing the agglomeration of the positive electrode conductive agent, reducing the resistance of the positive electrode sheet, and further reducing the impedance of the battery and improving the interfacial performance of the electrode assembly, thereby further improving the interfacial dynamics and cycle performance of the battery. Furthermore, the side chain groups of the dispersant also contain functional groups such as carboxylate, sulfonate, sulfinate, amide, and carbamate groups, thereby achieving a better dispersion effect, reducing the agglomeration of the positive electrode conductive agent and lowering the resistance of the positive electrode sheet even with a small addition amount.

[0197] [Preparation method of dispersant]

[0198] The present invention also provides a method for preparing the above-mentioned dispersant.

[0199] The method comprises the following steps: providing a solvent, a catalyst, a diisocyanate O=C=N—R1—N=C=O, an aliphatic diol HO—R2—OH and a polyether diol H—(O—R3) y —OH, diisocyanate O=C=N—R1—N=C=O, aliphatic diol HO—R2—OH, polyether diol H—(O—R3) y The molar ratio of —OH is x:x:1, and the definitions of R1, R2, R3, x, and y are as defined above.

[0200] A solvent, a catalyst, a diisocyanate and an aliphatic diol are added to a reactor for a gradual polymerization reaction to obtain an intermediate; then a polyether diol is added to the reactor to allow the obtained intermediate to continue to react with the polyether diol, and a dispersant is obtained after the reaction is completed.

[0201] In some embodiments, in the step of adding the solvent, catalyst, diisocyanate and aliphatic diol into a reactor for stepwise polymerization, the reaction temperature may be 0-80°C, optionally 30-55°C.

[0202] In some embodiments, in the step of adding the solvent, catalyst, diisocyanate and aliphatic diol into a reactor to carry out a stepwise polymerization reaction, the reaction time may be 1-6 hours, and optionally 1.5-4 hours.

[0203] In some embodiments, the polyether diol is added to the reactor, and the obtained intermediate and the polyether diol are allowed to react for 2-4 hours, and optionally 2.5-3.5 hours.

[0204] In some embodiments, the catalyst may include, but is not limited to, one or more of methacrylates, phosphonates, organic leads (such as lead acetate, lead octoate), organic amines (such as triethylenediamine DABCO, triethylamine, trimethylbenzylamine, dimethylethanolamine, morpholine), and organic tin (such as dibutyltin dilaurate, stannous octoate).

[0205] In some embodiments, the weight of the catalyst may be 0.3-1.0 wt %, optionally 0.4-0.6 wt %, based on the weight of the diisocyanate.

[0206] In some embodiments, the solvent may include, but is not limited to, one or more of tetrahydrofuran, N,N-dimethylacetamide, N,N-dimethylformamide, toluene, xylene, acetone, methyl ethyl ketone, cyclohexanone, and dioxane.

[0207] [Positive electrode]

[0208] The embodiment of the present application also provides a positive electrode plate.

[0209] The positive electrode sheet includes a positive electrode current collector and a positive electrode film layer arranged on at least one surface of the positive electrode current collector, the positive electrode film layer includes a positive electrode active material, a positive electrode conductor, a positive electrode binder and a dispersant, wherein the dispersant includes the dispersant provided in the embodiment of the present application or the dispersant prepared by the method provided in the embodiment of the present application.

[0210] The positive electrode current collector has two surfaces opposite to each other in its thickness direction, and the positive electrode film layer is arranged on either one or both of the two opposite surfaces of the positive electrode current collector.

[0211] In some embodiments, the dispersant content can be 0.1-0.5wt%, optionally 0.1-0.4wt%, 0.2-0.4wt%, or 0.2-0.3wt%, based on the total weight of the positive electrode film layer. When the dispersant content is within the above range, a good dispersion effect can be achieved. Furthermore, the functional groups such as carboxylate, sulfonate, sulfinate, amide, and carbamate groups in the polymer chain of the dispersant have a strong affinity for the electrolyte, thereby increasing the electrolyte wetting ability of the positive electrode sheet, shortening the wetting time, and enabling the battery to have high energy density, good kinetic performance, and good cycling performance.

[0212] In some embodiments, based on the total weight of the positive electrode film layer, the content of the positive electrode active material may be 91.5-99.5 wt %. When the content of the positive electrode active material is within the above range, the battery can have a high energy density.

[0213] In some embodiments, based on the total weight of the positive electrode film layer, the content of the positive electrode conductive agent may be 0.1-4 wt %.

[0214] In some embodiments, based on the total weight of the positive electrode film layer, the content of the positive electrode binder may be 0.1-4 wt %.

[0215] The positive electrode active material may be any material known in the art, and the present invention is not limited thereto.

[0216] The positive electrode active material can extract and insert lithium ions or sodium ions.

[0217] In some embodiments, when the battery cell is a lithium-ion battery cell or a lithium metal battery cell, the positive electrode active material may include, but is not limited to, one or more of lithium transition metal oxides, lithium-containing phosphates, and their respective modified compounds. Examples of lithium transition metal oxides may include, but are not limited to, one or more of lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, and their respective modified compounds. Examples of lithium-containing phosphates may include, but are not limited to, one or more of lithium iron phosphate, a composite material of lithium iron phosphate and carbon, lithium manganese phosphate, a composite material of lithium manganese phosphate and carbon, lithium iron manganese phosphate, a composite material of lithium iron manganese phosphate and carbon, and their respective modified compounds. These positive electrode active materials may be used alone or in combination of two or more.

[0218] In some embodiments, in order to further improve the energy density of the battery, the positive electrode active material may include a general formula of Li a Ni b Co c M d O e A f One or more lithium transition metal oxides and modified compounds thereof. 0.8≤a≤1.2, 0.5≤b<1, 0<c<1, 0<d<1, 1≤e≤2, 0≤f≤1, M includes one or more of Mn, Al, Zr, Zn, Cu, Cr, Mg, Fe, V, Ti and B, and A includes one or more of N, F, S and Cl.

[0219] As an example, the positive electrode active material may include LiCoO2, LiNiO2, LiMnO2, LiMn2O4, LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (abbreviated as NCM333), LiNi 0.5 Co 0.2 Mn 0.3 O2 (abbreviated as NCM523), LiNi 0.5 Co 0.25 Mn 0.25 O2 (abbreviated as NCM211), LiNi 0.6 Co0.2 Mn 0.2 O2 (abbreviated as NCM622), LiNi 0.8 Co 0.1 Mn 0.1 O2 (abbreviated as NCM811), LiNi 0.96 Co 0.02 Mn 0.02 O2 (abbreviated as Ni96), LiNi 0.85 Co 0.15 Al 0.05 One or more of O2, LiFePO4, LiMnPO4.

[0220] In some embodiments, when the battery cells are sodium ion battery cells or sodium metal battery cells, the positive electrode active materials may include, but are not limited to, one or more of sodium transition metal oxides, polyanionic materials (such as phosphates, fluorophosphates, pyrophosphates, sulfates, etc.), Prussian blue materials, and their respective modified compounds. These positive electrode active materials may be used alone or in combination of two or more.

[0221] As an example, the positive electrode active material may include, but is not limited to, sodium iron composite oxide (such as NaFeO2), sodium cobalt composite oxide (such as NaCoO2), sodium chromium composite oxide (such as NaCrO2), sodium manganese composite oxide (such as NaMnO2), sodium nickel composite oxide (such as NaNiO2), sodium nickel titanium composite oxide (such as NaNiO2), sodium nickel titanium composite oxide (such as NaNiO2), sodium iron composite oxide (such as NaFeO2), sodium cobalt composite oxide (such as NaCoO2), sodium chromium composite oxide (such as NaCrO2), sodium manganese composite oxide (such as NaMnO2), sodium nickel ... 1 / 2 Ti 1 / 2 O2), sodium nickel manganese composite oxides (such as NaNi 1 / 2 Mn 1 / 2 O2), sodium iron manganese composite oxide (such as Na 2 / 3 Fe 1 / 3 Mn 2 / 3 O2), sodium nickel cobalt manganese composite oxides (such as NaNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2), sodium iron phosphate compounds (such as NaFePO4), sodium manganese phosphate compounds (such as NaMnPO4), sodium cobalt phosphate compounds (such as NaCoPO4), Prussian blue materials and general formula X p M' q (PO4) r O x Y 3-x One or more materials. p M' q (PO4) r O x Y 3-x , 0<p≤4, 0<q≤2, 1≤r≤3, 0≤x≤2, X includes H+ 、Li + 、Na + , K + and NH4 + One or more of, M' comprises a transition metal, which may be selected from one or more of V, Ti, Mn, Fe, Co, Ni, Cu and Zn, and Y comprises a halogen, which may be selected from one or more of F, Cl and Br.

[0222] The modified compounds of the above-mentioned positive electrode active materials may be used to perform doping modification and / or surface coating modification on the positive electrode active materials.

[0223] The present application has no particular limitation on the type of positive electrode conductive agent. In some embodiments, as examples, the positive electrode conductive agent may include one or more of superconducting carbon, conductive graphite, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0224] The present application does not particularly limit the type of positive electrode binder. In some embodiments, as an example, the positive electrode binder may include one or more of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorine-containing acrylic resin.

[0225] In some embodiments, the positive electrode current collector may be a metal foil or a composite current collector. As an example of a metal foil, aluminum foil may be used. The composite current collector may include a polymer material base layer and a metal material layer formed on at least one surface of the polymer material base layer. As an example, the metal material may include one or more of aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy. As an example, the polymer material base layer may include one or more of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), and polyethylene (PE).

[0226] [Cathode slurry]

[0227] The embodiment of the present application also provides a positive electrode slurry.

[0228] The positive electrode slurry includes a solid component (i.e., a non-solvent component) and a solvent, wherein the solid component includes a positive electrode active material, a positive electrode conductor, a positive electrode binder and a dispersant, wherein the dispersant includes the dispersant provided in the embodiments of the present application or a dispersant prepared by the method provided in the embodiments of the present application.

[0229] In some embodiments, the content of the dispersant may be 0.1-0.5 wt %, optionally 0.2-0.3 wt %, based on the total weight of the solid components.

[0230] In some embodiments, the positive electrode active material may be present in an amount of 91.5-99.5 wt % based on the total weight of the solid components.

[0231] In some embodiments, the positive electrode conductive agent may be present in an amount of 0.1-4 wt % based on the total weight of the solid components.

[0232] In some embodiments, the positive electrode binder may be present in an amount of 0.1-4 wt % based on the total weight of the solid components.

[0233] The positive electrode slurry is usually formed by dispersing the positive electrode active material, positive electrode conductor, positive electrode binder, dispersant and any other components in a solvent according to a predetermined ratio and stirring them uniformly.

[0234] In some embodiments, the solvent may include an organic solvent. For example, the solvent may be N-methylpyrrolidone (NMP), but is not limited thereto.

[0235] In some embodiments, the solid content of the positive electrode slurry may be 50%-75%.

[0236] [Preparation method of positive electrode sheet]

[0237] The present invention also provides a method for preparing a positive electrode sheet by a wet process, comprising the steps of applying the positive electrode slurry provided in the present invention to a positive electrode current collector, drying the slurry, and rolling the slurry to obtain a positive electrode sheet.

[0238] During the wet-process preparation of positive electrode sheets, dispersants can reduce the agglomeration of the positive electrode conductive agent, lower the battery impedance, and improve the interfacial properties of the electrode assembly, enhancing the battery's interfacial dynamics and cycle performance. Furthermore, dispersants can reduce the gelation problem of the positive electrode slurry, thereby improving the coating and processing properties of the positive electrode sheet.

[0239] The present application also provides another dry-process method for preparing a positive electrode sheet. The method comprises the following steps: mixing a positive electrode conductive agent, a positive electrode binder, a dispersant, and a solvent to form a conductive slurry; kneading the positive electrode active material and the conductive slurry to form a mass; extruding or hot-pressing the mass to form a film; thinning the film by roller pressing, laminating it with a positive electrode current collector, and drying it to obtain a positive electrode sheet.

[0240] In the process of dry preparation of positive electrode sheets, dispersants can reduce the agglomeration of positive electrode conductive agents, reduce the impedance of the battery, and improve the interface performance of the electrode assembly, thereby improving the interface dynamics of the battery and the cycle performance of the battery.

[0241] In some embodiments, in the step of kneading the positive electrode active material and the conductive slurry to form a mass, the equipment used may be an internal mixer, a kneader, a twin-screw device, and the like.

[0242] In some embodiments, the step of extruding or hot-pressing the obtained mass into a film can employ an apparatus such as a twin-screw extruder, a hydraulic extruder, a plunger extruder, a hot press, or an open mill. The screw elements of the twin-screw extruder can be a combination of one or more of a screw member, an engaging block, and a toothed disk, thereby achieving a sufficient balance between shear mixing and conveying capabilities.

[0243] In some embodiments, the solid content of the conductive paste may be 3-20%.

[0244] In some embodiments, the solid content of the mass material can be 70%-95%. The mass material contains a small amount of solvent, which is beneficial to the subsequent roller thinning process of the membrane formed by extrusion or hot pressing. The role of a small amount of solvent is similar to that of a "lubricant", which can promote particle slippage, and thus the membrane is not prone to excessive rolling during the subsequent roller thinning process. The membrane formed by extrusion or hot pressing can also be softer, have better processing performance, and be easier to be compacted and form thicker pole pieces, which is beneficial to obtaining a high energy density battery. The amount of solvent used in the dry process of preparing positive electrode sheets is lower than that in the wet process of preparing positive electrode sheets, which can also reduce raw material costs and energy consumption costs, while also reducing environmental pollution.

[0245] [Negative electrode]

[0246] The battery cell includes a negative electrode plate. The structure and composition of the negative electrode plate can be selected according to the type of battery cell, and the embodiments of the present application are not limited to this.

[0247] In some embodiments, the negative electrode sheet may include a negative electrode current collector and a negative electrode film layer disposed on at least one surface of the negative electrode current collector, wherein the negative electrode film layer includes a negative electrode active material.

[0248] The negative electrode current collector has two surfaces opposite to each other in its thickness direction, and the negative electrode film layer is arranged on either one or both of the two opposite surfaces of the negative electrode current collector.

[0249] In some embodiments, the negative electrode current collector may be a metal foil or a composite current collector. As examples of metal foils, copper foil, copper alloy foil, aluminum foil, and aluminum alloy foil may be used. The composite current collector may include a polymer material base layer and a metal material layer formed on at least one surface of the polymer material base layer. As an example, the metal material may include one or more of copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy. As an example, the polymer material base layer may include one or more of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), and polyethylene (PE).

[0250] The negative electrode active material may be a negative electrode active material for a battery that is well known in the art. In some embodiments, as an example, the negative electrode active material may include, but is not limited to, one or more of natural graphite, artificial graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate. Silicon-based materials may include one or more of elemental silicon, silicon oxide, silicon-carbon composites, silicon-nitrogen composites, and silicon alloy materials. Tin-based materials may include one or more of elemental tin, tin oxide, and tin alloy materials. The present application is not limited to these materials, and other conventionally known materials that can be used as negative electrode active materials for batteries may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0251] In some embodiments, the negative electrode film layer may further optionally include a negative electrode conductive agent. The present application does not particularly limit the type of the negative electrode conductive agent. For example, the negative electrode conductive agent may include one or more of superconducting carbon, conductive graphite, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0252] In some embodiments, the negative electrode film layer may further optionally include a negative electrode binder. The present application does not particularly limit the type of the negative electrode binder. As examples, the negative electrode binder may include one or more of styrene-butadiene rubber (SBR), water-soluble unsaturated resin SR-1B, water-based acrylic resin (e.g., polyacrylic acid PAA, polymethacrylic acid PMAA, sodium polyacrylate PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), and carboxymethyl chitosan (CMCS).

[0253] In some embodiments, the negative electrode film layer may further include other additives, such as thickeners, sodium carboxymethyl cellulose (CMC), PTC thermistor materials, and the like.

[0254] The negative electrode film layer is typically formed by coating the negative electrode slurry onto the negative electrode current collector, drying it, and cold pressing it. The negative electrode slurry is typically formed by dispersing the negative electrode active material, an optional negative electrode conductive agent, an optional negative electrode binder, and other optional additives in a solvent and stirring them uniformly. The solvent can be, but is not limited to, N-methylpyrrolidone (NMP) or deionized water.

[0255] The negative electrode plate does not exclude other additional functional layers in addition to the negative electrode film layer. For example, in some embodiments, the negative electrode plate may further include a conductive primer layer (e.g., composed of a conductive agent and a binder) sandwiched between the negative electrode current collector and the negative electrode film layer and disposed on the surface of the negative electrode current collector; in some embodiments, the negative electrode plate may further include a protective layer covering the surface of the negative electrode film layer.

[0256] In some embodiments, the negative electrode sheet may include a negative electrode current collector and a first metal layer disposed on at least one surface of the negative electrode current collector. The metal element in the first metal layer may include one or more alkali metal elements.

[0257] In some embodiments, the metal material in the first metal layer may include one or more of lithium, lithium alloy, sodium, and sodium alloy.

[0258] A lithium alloy may be an alloy of metallic lithium and other metallic elements or non-metallic elements. For example, the other metallic elements in the lithium alloy may include one or more of tin, zinc, aluminum, magnesium, silver, gold, gallium, indium, and platinum, and the non-metallic elements in the lithium alloy may include one or more of boron, carbon, and silicon.

[0259] The sodium alloy may be an alloy of metallic sodium and other metallic elements or non-metallic elements. For example, the other metallic elements in the sodium alloy may include one or more of tin, zinc, aluminum, magnesium, silver, gold, gallium, indium, and platinum, and the non-metallic elements in the sodium alloy may include one or more of boron, carbon, and silicon.

[0260] In some embodiments, the negative electrode sheet may include a negative electrode current collector but not the first metal layer, thereby being assembled to form a negative electrode metal-free battery cell.

[0261] In some embodiments, the negative electrode plate may also be made of a sheet (or foil) of lithium, lithium alloy, sodium, or sodium alloy.

[0262] [Electrolytes]

[0263] Battery cells include an electrolyte. The electrolyte conducts ions between the positive and negative electrodes. This application does not specifically limit the type of electrolyte; it can be selected based on needs. For example, the electrolyte can include one or more of a solid electrolyte, a gel electrolyte, and a liquid electrolyte (i.e., an electrolyte solution).

[0264] In some embodiments, the electrolyte is an electrolyte solution including an electrolyte salt and a solvent.

[0265] When the battery cell is a lithium ion battery cell or a lithium metal battery cell, as an example, the electrolyte salt may include one or more of lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium perchlorate (LiClO4), lithium hexafluoroarsenate (LiAsF6), lithium bisfluorosulfonyl imide (LiFSI), lithium bistrifluoromethanesulfonyl imide (LiTFSI), lithium trifluoromethanesulfonate (LiTFS), lithium difluorooxalatoborate (LiDFOB), lithium dioxalatoborate (LiBOB), lithium difluorophosphate (LiPO2F2), lithium difluorobisoxalatophosphate (LiDFOP) and lithium tetrafluorooxalatophosphate (LiTFOP).

[0266] When the battery cell is a sodium ion battery cell or a sodium metal battery cell, as an example, the electrolyte salt may include one or more of sodium hexafluorophosphate (NaPF6), sodium tetrafluoroborate (NaBF4), sodium perchlorate (NaClO4), sodium hexafluoroarsenate (NaAsF6), sodium bisfluorosulfonyl imide (NaFSI), sodium bistrifluoromethanesulfonyl imide (NaTFSI), sodium trifluoromethanesulfonate (NaTFS), sodium difluorooxalatoborate (NaDFOB), sodium dioxalatoborate (NaBOB), sodium difluorophosphate (NaPO2F2), sodium difluorobisoxalatophosphate (NaDFOP) and sodium tetrafluorooxalatophosphate (NaTFOP).

[0267] The type of solvent is not particularly limited and can be selected according to actual needs. In some embodiments, as an example, the solvent may include ethylene carbonate (EC), propylene carbonate (PC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), butylene carbonate (BC), fluoroethylene carbonate (FEC), methyl formate (MF), methyl acetate (MA), ethyl acetate (EA), propyl acetate (PA), methyl propionate (MPC), propyl propionate ... One or more of ethyl acetate (EP), propyl propionate (PP), methyl butyrate (MB), ethyl butyrate (EB), 1,4-butyrolactone (GBL), sulfolane (SF), dimethyl sulfone (MSM), ethyl methyl sulfone (EMS), diethyl sulfone (ESE), dimethoxymethane, diethoxymethane, dipropoxymethane, 1,2-dimethoxyethane, dimethoxypropane, 1,2-diethoxyethane, ethylene glycol methyl ethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, and tetraethylene glycol dimethyl ether.

[0268] In some embodiments, the electrolyte may optionally include additives. For example, the additives may include negative electrode film-forming additives, positive electrode film-forming additives, or additives that can improve certain battery properties, such as additives that improve battery overcharge performance, additives that improve battery high-temperature performance, and additives that improve battery low-temperature power performance.

[0269] [Isolation film]

[0270] The battery cell may also include a separator. This separator can be placed between the positive and negative electrode sheets, primarily to prevent internal short circuits. This application does not specifically limit the type of separator; any known porous membrane with good chemical and mechanical stability may be used.

[0271] In some embodiments, the material of the isolation membrane may include one or more of glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and polyimide. The isolation membrane may be a single-layer film or a multi-layer composite film. When the isolation membrane is a multi-layer composite film, the materials of each layer may be the same or different.

[0272] The preparation method of battery cells is well known. In some embodiments, the positive electrode sheet, separator, negative electrode sheet and electrolyte can be assembled to form a battery cell. As an example, the positive electrode sheet, separator, and negative electrode sheet can be formed into an electrode assembly through a winding process and / or a lamination process, and the electrode assembly is placed in an outer package, dried and injected with the above-mentioned electrolyte, and then subjected to vacuum packaging, standing, formation, shaping and other processes to obtain a battery cell. Multiple battery cells can also be further connected in series, in parallel or in a mixed connection to form a battery module. Multiple battery modules can also be connected in series, in parallel or in a mixed connection to form a battery pack. In some embodiments, multiple battery cells can also directly form a battery pack.

[0273] Electrical devices

[0274] The present application also provides an electrical device, which includes a battery provided in the present application. The battery can be used as a power source for the electrical device or as an energy storage unit for the electrical device. The electrical device can be, but is not limited to, a mobile device (such as a mobile phone, a tablet computer, a laptop computer, etc.), an electric vehicle (such as a pure electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, an electric bicycle, an electric scooter, an electric golf cart, an electric truck, etc.), an electric train, a ship, a satellite, an energy storage system, etc.

[0275] The electrical device can select a specific type of battery, such as a battery cell, a battery module, or a battery pack, according to its usage requirements.

[0276] Figure 6 is a schematic diagram of an exemplary electric device. This device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle. To meet the high power and high energy density requirements of this device, a battery pack or battery module may be used.

[0277] As another example, an electric device may be a mobile phone, a tablet computer, a laptop computer, etc. Such an electric device is usually required to be lightweight and thin, and may use a battery cell as a power source.

[0278] Example

[0279] The following examples describe the present disclosure in more detail and are intended to be illustrative only, as various modifications and variations within the scope of the present disclosure will be apparent to those skilled in the art. Unless otherwise indicated, all parts, percentages, and ratios reported in the following examples are by weight, and all reagents used in the examples are commercially available or synthesized according to conventional methods and used directly without further processing, and all instruments used in the examples are commercially available.

[0280] Example 1

[0281] (1) Preparation of dispersant

[0282] The catalyst, dibutyltin dilaurate, and the diisocyanate and aliphatic diol listed in Table 1 (molar ratio of 1:1) were added to a reactor using tetrahydrofuran as the solvent. The reaction temperature was then controlled at 50°C under a nitrogen atmosphere for 2.5 hours. Afterwards, the polyether diol listed in Table 1 was added and stirred for 3 hours to produce the dispersant shown in Table 1. The molar weights of the diisocyanate and aliphatic diol were x mol, and the degree of polymerization of the polyether diol was y, with a molar weight of 1 mol. The values ​​of x and y are shown in Table 1. The weight of the catalyst was 0.4-0.6 wt% of the weight of the diisocyanate.

[0283] (2) Preparation of positive electrode sheet

[0284] A conductive paste with a solid content of 4.3% was prepared by mixing carbon black, a positive electrode binder (PVDF), the dispersant prepared above, and NMP as a solvent. The positive electrode active material and the conductive paste were kneaded in a kneader to form a mass with a solid content of 75%. The mass was extruded through a twin-screw extruder to form a film of uniform thickness. The prepared film was then thinned by rollers to form a soft film. The film was then laminated with aluminum foil, a positive electrode current collector, and then dried in an oven. After further cold pressing and slitting, the positive electrode sheets were obtained. The weight ratio of the positive electrode active material, positive electrode conductive agent, positive electrode binder, and dispersant was 97.2:0.7:1.8:0.3.

[0285] (3) Preparation of negative electrode sheet

[0286] The negative electrode active material graphite, binder styrene-butadiene rubber (SBR), thickener sodium carboxymethyl cellulose (CMC-Na), and conductive agent carbon black (Super P) are fully stirred and mixed in an appropriate amount of solvent deionized water at a mass ratio of 96.2:1.8:1.2:0.8 to form a uniform negative electrode slurry; the negative electrode slurry is evenly coated on the surface of the negative electrode current collector copper foil, and after drying and cold pressing, a negative electrode sheet is obtained.

[0287] (4) Preparation of electrolyte

[0288] Ethylene carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) are mixed in a volume ratio of 1:1:1 to obtain an organic solvent, and then fully dried LiPF6 is dissolved in the above organic solvent to prepare an electrolyte with a concentration of 1 mol / L.

[0289] (5) Preparation of isolation membrane

[0290] A porous polyethylene film was used as the separator.

[0291] (6) Preparation of batteries

[0292] The positive electrode sheet, separator, and negative electrode sheet are stacked and wound in sequence to obtain an electrode assembly; the electrode assembly is placed in an outer package, dried, and then injected with electrolyte. After vacuum packaging, standing, formation, shaping and other processes, a battery is obtained.

[0293] Example 2

[0294] The preparation method of the battery of Example 2 is similar to that of Example 1, except that the type and preparation process of the dispersant are different.

[0295] The catalyst, dibutyltin dilaurate, and the diisocyanate and aliphatic diol listed in Table 1 (molar ratio of 1:1) were added to a reactor using tetrahydrofuran as the solvent. The reaction temperature was then controlled at 45°C under an N2 atmosphere for 2 hours. Afterwards, the polyether diol listed in Table 1 was added and stirred for 3 hours to produce the dispersant shown in Table 1. The molar weights of the diisocyanate and aliphatic diol were x mol, and the degree of polymerization of the polyether diol was y, with a molar weight of 1 mol. The values ​​of x and y are shown in Table 1. The weight of the catalyst was 0.4-0.6 wt% of the weight of the diisocyanate.

[0296] Example 3

[0297] The preparation method of the battery of Example 3 is similar to that of Example 1, except that the type of dispersant and the preparation process are different.

[0298] The catalyst, dibutyltin dilaurate, and the diisocyanate and aliphatic diol listed in Table 1 (molar ratio of 1:1) were added to a reactor using tetrahydrofuran as the solvent. The reaction temperature was then controlled at 50°C under a nitrogen atmosphere for 2 hours. Afterwards, the polyether diol listed in Table 1 was added and stirred for 3 hours to produce the dispersant shown in Table 1. The molar weights of the diisocyanate and aliphatic diol were x mol, and the degree of polymerization of the polyether diol was y, with a molar weight of 1 mol. The values ​​of x and y are shown in Table 1. The weight of the catalyst was 0.4-0.6 wt% of the weight of the diisocyanate.

[0299] Example 4

[0300] The preparation method of the battery of Example 4 is similar to that of Example 1, except that the type of dispersant and the preparation process are different.

[0301] The catalyst, dibutyltin dilaurate, and the diisocyanate and aliphatic diol listed in Table 1 (molar ratio of 1:1) were added to a reactor using tetrahydrofuran as the solvent. The reaction temperature was then controlled at 30°C under a nitrogen atmosphere for 2.5 hours. Afterwards, the polyether diol listed in Table 1 was added and stirred for 3 hours to produce the dispersant shown in Table 1. The molar weights of the diisocyanate and aliphatic diol were x mol, and the degree of polymerization of the polyether diol was y, with a molar weight of 1 mol. The values ​​of x and y are shown in Table 1. The weight of the catalyst was 0.4-0.6 wt% of the weight of the diisocyanate.

[0302] Example 5

[0303] The preparation method of the battery of Example 5 is similar to that of Example 1, except that the type and preparation process of the dispersant are different.

[0304] The catalyst, dibutyltin dilaurate, and the diisocyanate and aliphatic diol listed in Table 1 (molar ratio of 1:1) were added to a reactor using tetrahydrofuran as the solvent. The reaction temperature was then controlled at 50°C under a nitrogen atmosphere for 2 hours. Afterwards, the polyether diol listed in Table 1 was added and stirred for 3 hours to produce the dispersant shown in Table 1. The molar weights of the diisocyanate and aliphatic diol were x mol, and the degree of polymerization of the polyether diol was y, with a molar weight of 1 mol. The values ​​of x and y are shown in Table 1. The weight of the catalyst was 0.4-0.6 wt% of the weight of the diisocyanate.

[0305] Example 6

[0306] The preparation method of the battery of Example 6 is similar to that of Example 1, except that the type and preparation process of the dispersant are different.

[0307] The catalyst, dibutyltin dilaurate, and the diisocyanate and aliphatic diol listed in Table 1 (molar ratio of 1:1) were added to a reactor using tetrahydrofuran as the solvent. The reaction temperature was then controlled at 55°C under an N2 atmosphere for 2.5 hours. Afterwards, the polyether diol listed in Table 1 was added and stirred for 3 hours to produce the dispersant shown in Table 1. The molar weights of the diisocyanate and aliphatic diol were x mol, and the degree of polymerization of the polyether diol was y, with a molar weight of 1 mol. The values ​​of x and y are shown in Table 1. The weight of the catalyst was 0.4-0.6 wt% of the weight of the diisocyanate.

[0308] Example 7

[0309] The preparation method of the battery of Example 7 is similar to that of Example 1, except that the type and preparation process of the dispersant are different.

[0310] The catalyst, dibutyltin dilaurate, and the diisocyanate and aliphatic diol listed in Table 1 (molar ratio of 1:1) were added to a reactor using tetrahydrofuran as the solvent. The reaction temperature was then controlled at 55°C under a nitrogen atmosphere for 3.5 hours. Afterwards, the polyether diol listed in Table 1 was added and stirred for 3 hours to produce the dispersant shown in Table 1. The molar weights of the diisocyanate and aliphatic diol were x mol, and the degree of polymerization of the polyether diol was y, with a molar weight of 1 mol. The values ​​of x and y are shown in Table 1. The weight of the catalyst was 0.4-0.6 wt% of the weight of the diisocyanate.

[0311] Example 8

[0312] The preparation method of the battery of Example 8 is similar to that of Example 1, except that the type and preparation process of the dispersant are different.

[0313] The catalyst, dibutyltin dilaurate, and the diisocyanate and aliphatic diol listed in Table 1 (molar ratio of 1:1) were added to a reactor using tetrahydrofuran as the solvent. The reaction temperature was then controlled at 55°C under a nitrogen atmosphere for 3.5 hours. Afterwards, the polyether diol listed in Table 1 was added and stirred for 3 hours to produce the dispersant shown in Table 1. The molar weights of the diisocyanate and aliphatic diol were x mol, and the degree of polymerization of the polyether diol was y, with a molar weight of 1 mol. The values ​​of x and y are shown in Table 1. The weight of the catalyst was 0.4-0.6 wt% of the weight of the diisocyanate.

[0314] Example 9

[0315] The preparation method of the battery of Example 9 is similar to that of Example 1, except that the type and preparation process of the dispersant are different.

[0316] The catalyst, dibutyltin dilaurate, and the diisocyanate and aliphatic diol listed in Table 1 (molar ratio of 1:1) were added to a reactor using tetrahydrofuran as the solvent. The reaction temperature was then controlled at 45°C under an N2 atmosphere for 3 hours. Afterwards, the polyether diol listed in Table 1 was added and stirred for 3 hours to produce the dispersant shown in Table 1. The molar weights of the diisocyanate and aliphatic diol were x mol, and the degree of polymerization of the polyether diol was y, with a molar weight of 1 mol. The values ​​of x and y are shown in Table 1. The weight of the catalyst was 0.4-0.6 wt% of the weight of the diisocyanate.

[0317] Example 10

[0318] The preparation method of the battery of Example 10 is similar to that of Example 1, except that the type and preparation process of the dispersant are different.

[0319] The catalyst, dibutyltin dilaurate, and the diisocyanate and aliphatic diol listed in Table 1 (molar ratio of 1:1) were added to a reactor using tetrahydrofuran as the solvent. The reaction temperature was then controlled at 35°C under a nitrogen atmosphere for 1.5 hours. Afterwards, the polyether diol listed in Table 1 was added and stirred for 3 hours to produce the dispersant listed in Table 1. The molar weights of the diisocyanate and aliphatic diol were x mol, and the degree of polymerization of the polyether diol was y, with a molar weight of 1 mol. The values ​​of x and y are shown in Table 1. The weight of the catalyst was 0.4-0.6 wt% of the weight of the diisocyanate.

[0320] Example 11

[0321] The preparation method of the battery of Example 11 is similar to that of Example 1, except that the type of dispersant and the preparation process are different.

[0322] The catalyst, dibutyltin dilaurate, and the diisocyanate and aliphatic diol listed in Table 1 (molar ratio 1:1) were added to a reactor using tetrahydrofuran as the solvent. The reaction temperature was then controlled at 35°C under a nitrogen atmosphere for 2.5 hours. Afterwards, the polyether diol listed in Table 1 was added and stirred for 3 hours to produce the dispersant shown in Table 1. The molar weights of the diisocyanate and aliphatic diol were x mol, and the degree of polymerization of the polyether diol was y, with a molar weight of 1 mol. The values ​​of x and y are shown in Table 1. The weight of the catalyst was 0.4-0.6 wt% of the weight of the diisocyanate.

[0323] Example 12

[0324] The preparation method of the battery of Example 12 is similar to that of Example 1, except that the type and preparation process of the dispersant are different.

[0325] The catalyst, dibutyltin dilaurate, and the diisocyanate and aliphatic diol listed in Table 1 (molar ratio of 1:1) were added to a reactor using tetrahydrofuran as the solvent. The reaction temperature was then controlled at 45°C under an N2 atmosphere for 2 hours. Afterwards, the polyether diol listed in Table 1 was added and stirred for 3 hours to produce the dispersant shown in Table 1. The molar weights of the diisocyanate and aliphatic diol were x mol, and the degree of polymerization of the polyether diol was y, with a molar weight of 1 mol. The values ​​of x and y are shown in Table 1. The weight of the catalyst was 0.4-0.6 wt% of the weight of the diisocyanate.

[0326] Example 13

[0327] The preparation method of the battery of Example 13 is similar to that of Example 4, except that the number average molecular weight of the dispersant is different.

[0328] The catalyst, dibutyltin dilaurate, and the diisocyanate and aliphatic diol listed in Table 1 (molar ratio of 1:1) were added to a reactor using tetrahydrofuran as the solvent. The reaction temperature was then controlled at 30°C under a nitrogen atmosphere for 1.5 hours. Afterwards, the polyether diol listed in Table 1 was added and stirred for 3 hours to produce the dispersant shown in Table 1. The molar weights of the diisocyanate and aliphatic diol were x mol, and the degree of polymerization of the polyether diol was y, with a molar weight of 1 mol. The values ​​of x and y are shown in Table 1. The weight of the catalyst was 0.4-0.6 wt% of the weight of the diisocyanate.

[0329] Example 14

[0330] The preparation method of the battery of Example 14 is similar to that of Example 4, except that the number average molecular weight of the dispersant is different.

[0331] The catalyst, dibutyltin dilaurate, and the diisocyanate and aliphatic diol listed in Table 1 (molar ratio of 1:1) were added to a reactor using tetrahydrofuran as the solvent. The reaction temperature was then controlled at 30°C under an N2 atmosphere for 2 hours. Afterwards, the polyether diol listed in Table 1 was added and stirred for 3 hours to produce the dispersant shown in Table 1. The molar weights of the diisocyanate and aliphatic diol were x mol, and the degree of polymerization of the polyether diol was y, with a molar weight of 1 mol. The values ​​of x and y are shown in Table 1. The weight of the catalyst was 0.4-0.6 wt% of the weight of the diisocyanate.

[0332] Example 15

[0333] The preparation method of the battery of Example 15 is similar to that of Example 4, except that the number average molecular weight of the dispersant is different.

[0334] The catalyst, dibutyltin dilaurate, and the diisocyanate and aliphatic diol listed in Table 1 (molar ratio of 1:1) were added to a reactor using tetrahydrofuran as the solvent. The reaction temperature was then controlled at 30°C for 3 hours under an N2 atmosphere. Afterwards, the polyether diol listed in Table 1 was added and stirred for 3 hours to produce the dispersant shown in Table 1. The molar weights of the diisocyanate and aliphatic diol were x mol, and the degree of polymerization of the polyether diol was y, with a molar weight of 1 mol. The values ​​of x and y are shown in Table 1. The weight of the catalyst was 0.4-0.6 wt% of the weight of the diisocyanate.

[0335] Example 16

[0336] The preparation method of the battery of Example 16 is similar to that of Example 4, except that the number average molecular weight of the dispersant is different.

[0337] The catalyst, dibutyltin dilaurate, and the diisocyanate and aliphatic diol listed in Table 1 (molar ratio of 1:1) were added to a reactor using tetrahydrofuran as the solvent. The reaction temperature was then controlled at 35°C under an N2 atmosphere for 3.5 hours. Afterwards, the polyether diol listed in Table 1 was added and stirred for 3 hours to produce the dispersant shown in Table 1. The molar weights of the diisocyanate and aliphatic diol were x mol, and the degree of polymerization of the polyether diol was y, with a molar weight of 1 mol. The values ​​of x and y are shown in Table 1. The weight of the catalyst was 0.4-0.6 wt% of the weight of the diisocyanate.

[0338] Example 17

[0339] The preparation method of the battery of Example 17 is similar to that of Example 4, except that the number average molecular weight of the dispersant is different.

[0340] The catalyst, dibutyltin dilaurate, and the diisocyanate and aliphatic diol listed in Table 1 (molar ratio of 1:1) were added to a reactor using tetrahydrofuran as the solvent. The reaction temperature was then controlled at 35°C under an N2 atmosphere for 4 hours. Afterwards, the polyether diol listed in Table 1 was added and stirred for 3 hours to produce the dispersant shown in Table 1. The molar weights of the diisocyanate and aliphatic diol were x mol, and the degree of polymerization of the polyether diol was y, with a molar weight of 1 mol. The values ​​of x and y are shown in Table 1. The weight of the catalyst was 0.4-0.6 wt% of the weight of the diisocyanate.

[0341] Example 18

[0342] The preparation method of the battery of Example 18 is similar to that of Example 1, except that the number average molecular weight of the dispersant is different.

[0343] The catalyst, dibutyltin dilaurate, and the diisocyanate and aliphatic diol listed in Table 1 (molar ratio of 1:1) were added to a reactor using tetrahydrofuran as the solvent. The reaction temperature was then controlled at 50°C under an N2 atmosphere for 4 hours. Afterwards, the polyether diol listed in Table 1 was added and stirred for 3 hours to produce the dispersant shown in Table 1. The molar weights of the diisocyanate and aliphatic diol were x mol, and the degree of polymerization of the polyether diol was y, with a molar weight of 1 mol. The values ​​of x and y are shown in Table 1. The weight of the catalyst was 0.4-0.6 wt% of the weight of the diisocyanate.

[0344] Examples 19 to 22

[0345] The preparation method of the battery is similar to that of Example 4, except that the weight content of the dispersant in the positive electrode film layer is different, as shown in Table 2, and the weight content of the positive electrode conductor and the positive electrode binder remains unchanged.

[0346] Comparative Example 1

[0347] The preparation method of the battery is similar to that of Example 1, except that the positive electrode film layer does not contain a dispersant.

[0348] The positive electrode active material, lithium iron phosphate, and the positive electrode conductive agent, carbon black, are dry-blended to form solvent-free granules. Then, the positive electrode binders, PVDF and NMP, are added and kneaded to produce a positive electrode slurry with a solids content of 75%. The positive electrode slurry is extruded through a twin-screw extruder to produce a film of uniform thickness. The prepared film is then thinned by roller pressing to form a flexible film. The film is then laminated with the positive electrode current collector, aluminum foil, and then dried in an oven. After further cold pressing and slitting, the positive electrode sheets are obtained. The weight ratio of the positive electrode active material, positive electrode conductive agent, and positive electrode binder is 97.5:0.7:1.8.

[0349] Comparative Example 2

[0350] The preparation method of the battery of Comparative Example 2 is similar to that of Example 4, except that the number average molecular weight of the dispersant is different.

[0351] The catalyst, dibutyltin dilaurate, and the diisocyanate and aliphatic diol listed in Table 1 (molar ratio of 1:1) were added to a reactor using tetrahydrofuran as the solvent. The reaction temperature was then controlled at 35°C under an N2 atmosphere for 6 hours. Afterwards, the polyether diol listed in Table 1 was added and stirred for 3 hours to produce the dispersant shown in Table 1. The molar weights of the diisocyanate and aliphatic diol were x mol, and the degree of polymerization of the polyether diol was y, with a molar weight of 1 mol. The values ​​of x and y are shown in Table 1. The weight of the catalyst was 0.4-0.6 wt% of the weight of the diisocyanate.

[0352] Comparative Example 3

[0353] The preparation method of the battery of Comparative Example 3 is similar to that of Example 4, except that the number average molecular weight of the dispersant is different.

[0354] The catalyst, dibutyltin dilaurate, and the diisocyanate and aliphatic diol listed in Table 1 (molar ratio of 1:1) were added to a reactor using tetrahydrofuran as the solvent. The reaction temperature was then controlled at 30°C under a nitrogen atmosphere for 1 hour. Afterwards, the polyether diol listed in Table 1 was added and stirred for 3 hours to produce the dispersant shown in Table 1. The molar weights of the diisocyanate and aliphatic diol were x mol, and the degree of polymerization of the polyether diol was y, with a molar weight of 1 mol. The values ​​of x and y are shown in Table 1. The weight of the catalyst was 0.4-0.6 wt% of the weight of the diisocyanate.

[0355] Comparative Example 4

[0356] The preparation method of the battery is similar to that of Example 1, except that the dispersant uses the following compound, where x is 40.

[0357] Performance Testing

[0358] (1) Resistance test of positive electrode

[0359] Cut the cold-pressed positive electrode into 5cm x 5cm pieces and place them between the two electrodes of a resistance tester to measure the resistance of the positive electrode. A resistance tester such as the Yuanneng Technology BER2500 can be used.

[0360] (2) Battery DC internal resistance (DCR) test

[0361] At 25°C, the battery was charged at a constant current of 0.33C to a fully charged state (100% SOC), and then discharged at a constant current of 0.33C to 0.5Cn (Cn represents the battery capacity) to adjust the battery to 50% SOC; the battery was allowed to stand for 30 minutes, and the voltage after the end of the standing period was recorded as V1; thereafter, the battery was discharged at a current of 3C (recorded as I) for 30 seconds, and the discharge cut-off voltage was recorded as V2.

[0362] The DC internal resistance of the battery DCR = (V1-V2) / I, where V1 represents the end-of-rest voltage, V2 represents the end-of-discharge voltage, and I represents the discharge current.

[0363] (3) Battery rate performance test

[0364] At 25°C, the battery was charged to 3.65V at a constant current of 0.33C, and then continued to charge at a constant voltage to a current of 0.05C. After standing for 5 minutes, the battery was discharged to 2.5V at a constant current of 0.33C to obtain the discharge capacity of the battery at a rate of 0.33C; after the battery was stood for 30 minutes, it was charged to 3.65V at a constant current of 0.33C, and then continued to charge at a constant voltage to a current of 0.05C. After standing for 5 minutes, the battery was discharged to 2.5V at a constant current of 3C to obtain the discharge capacity of the battery at a rate of 3C.

[0365] The battery's rate performance is expressed as the ratio of the battery's discharge capacity at a 3C rate to the battery's discharge capacity at a 0.33C rate. The larger the ratio, the better the battery's rate performance.

[0366] (4) Cyclic performance test

[0367] At 25°C, charge the battery at a constant current of 1C to 3.65V, then continue to charge at a constant voltage to a current of 0.05C. After standing for 30 minutes, discharge the battery at a constant current of 1C to 2.5V, stand for 30 minutes, and record the battery's discharge capacity C0.

[0368] The battery was cycled as follows: at 25°C, the battery was charged to 3.65V at a constant current of 1C0, then continued to charge at a constant voltage to a current of 0.05C, and after standing for 30 minutes, the battery was discharged to 2.5V at a constant current of 1C0, and stood for 30 minutes. The discharge capacity of the battery in the first cycle is C1; the battery was cycled according to the above method, and the discharge capacity of the second cycle was C2, ..., and the discharge capacity of the 1200th cycle was C 1200 . With C 1200 / C1 represents the cycle performance of the battery, C 1200 The larger / C1 is, the better the cycle performance of the battery is.

[0369] Table 2

[0370] Figure 7 is a cross-sectional view of the positive electrode sheet prepared in Example 4. Figure 8 is a cross-sectional view of the positive electrode sheet prepared in Comparative Example 1. As shown in Figures 7 and 8, the positive electrode conductive agent in the positive electrode sheet prepared in Comparative Example 1 exhibits significant agglomeration. When the positive electrode sheet includes the dispersant provided in the examples of this application, the positive electrode conductive agent particles are more evenly dispersed, and the agglomeration problem is significantly reduced.

[0371] It can also be seen from the test results in Table 2 that the dispersant provided in the embodiments of the present application has good dispersibility, can effectively reduce the agglomeration of the positive electrode conductive agent when added in a small amount, and can also reduce the resistance of the positive electrode sheet, so that the battery can have high energy density, low impedance, good rate performance and cycle performance.

[0372] It can also be seen from the test results in Table 2 that when the dispersant includes the structures shown in B1 to B3 and / or includes long side chain groups with specific functional groups (carboxylate groups, sulfonate groups, sulfinic acid ester groups, amide groups, carbamate groups, etc.), the resistance of the positive electrode sheet can be further reduced, and the impedance of the battery can be further reduced, and the rate performance and cycle performance of the battery can be improved. This is because the structures and / or long side chain groups shown in B1 to B3 can produce a certain amount of steric hindrance, and the functional groups such as carboxylate groups, sulfonate groups, sulfinic acid ester groups, amide groups, and carbamate groups in the dispersant side chain groups can also make the dispersant have a better dispersion effect, thereby better dispersibility and reducing the agglomeration of the positive electrode conductive agent, thereby further reducing the resistance of the positive electrode sheet, and reducing the impedance of the battery, and improving the rate performance and cycle performance of the battery.

[0373] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are merely examples, and within the scope of the technical solution of the present application, embodiments having substantially the same structure as the technical idea and exerting the same effects are all included in the technical scope of the present application. In addition, within the scope of the subject matter of the present application, various modifications that can be conceived by those skilled in the art to the embodiments, and other methods constructed by combining some of the constituent elements in the embodiments are also included in the scope of the present application.

Claims

1. A dispersant having a structure represented by formula (I), R1 represents the residue of aliphatic, alicyclic and / or aromatic diisocyanate, R2 represents the residue of aliphatic diol, R3 represents C2-C8 alkylene, y represents an integer of 5-60, and the number average molecular weight of the dispersant is 10000-60000.

2. The dispersant according to claim 1, wherein R1 includes at least one of the first group, the second group, the third group, and the fourth group; The first group includes C2-C10 straight chain alkylene, and optionally includes C2-C6 straight chain alkylene; The second group includes R 11 , R 12 , R 13 , R 14 Each independently includes a hydrogen atom, a C1-C12 chain alkyl, a C1-C12 oxygen chain alkyl, a C1-C12 sulfur chain alkyl, a C3-C12 chain alkenyl, a 3-6 membered N-containing heterocyclic group, a 3-6 membered O-containing heterocyclic group, and a group represented by A1 to A6, and R 11 , R 12 , R 13 , R 14 Not all hydrogen atoms at the same time; Optionally, R 11 , R 12 , R 13 , R 14 Each independently includes a hydrogen atom, a C2-C8 chain alkyl group, a C3-C8 oxygen chain alkyl group, a C3-C8 sulfur chain alkyl group, a C4-C8 chain alkenyl group, and the groups represented by A1 to A6, and R 11 , R 12 , R 13 , R 14 At least one of them includes C3-C8 oxygen chain alkyl, C3-C8 sulfur chain alkyl, and the group represented by A1 to A6; R 15 Each independently includes a C1-C8 chain alkyl group, and optionally includes a C1-C3 chain alkyl group; R 16 Each independently includes a C1-C8 chain alkylene group, and optionally includes a C1-C3 chain alkylene group; The third group includes groups shown in B1 to B8, Optionally, the third group includes the following groups: The fourth group includes groups shown by D1 to D7, Optionally, the fourth group includes the following groups: R a Each independently includes one or more of cyano, amino, sulfonic acid and its salt, sulfonic acid ester, phosphate, C1-C8 oxo-chain alkyl, and C1-C8 chain alkyl; R b Each independently includes one or more of cyano, amino, sulfonic acid and its salt, sulfonic acid ester, phosphate, C1-C8 oxo-chain alkyl, and C1-C8 chain alkyl; p each independently represents an integer from 0 to 4, and is optionally 0 or 1; q each independently represents an integer from 0 to 6, and is optionally 0 or 1; and / or, R2 includes the following groups: R 21 , R 22 , R 23 , R 24 , R 25 , R 26 Each independently includes a hydrogen atom, a C1-C12 chain alkyl group, and a group represented by E1 to E4, and R 21 , R 22 , R 23 , R 24 , R 25 , R 26 Not all hydrogen atoms at the same time; Optionally, R 21 , R 22 , R 23 , R 24 , R 25 , R 26 Each independently includes a hydrogen atom, a C1-C12 chain alkyl group, and a group represented by E1 to E4, and R 21 , R 22 , R 23 , R 24 , R 25 , R 26 At least one of includes the groups shown in E1 to E4, R 27 Each independently includes a C1-C8 chain alkyl group, and optionally includes a C1-C4 chain alkyl group; R 28 Each independently includes a C1-C8 chain alkylene group, and optionally includes a C1-C3 chain alkylene group; and / or, R3 includes the following groups: # indicates the connection location.

3. The dispersant according to claim 2, wherein R1 includes at least one of the second group and the third group; The second group includes R 11 , R 12 , R 13 , R 14 Each independently includes a hydrogen atom, a C2-C8 chain alkyl group, a C3-C8 oxygen chain alkyl group, a C3-C8 sulfur chain alkyl group, and groups represented by A4 to A6, and R 11 , R 12 , R 13 , R 14 At least one of the following comprises the groups shown in A4 to A6; R 15 Each independently includes C1-C3 chain alkyl; R 16 Each independently includes C1-C3 chain alkylene; The third group includes groups shown in B1 to B3, R a Each independently includes one or more of cyano, amino, sulfonic acid and its salt, sulfonic acid ester, phosphate, C1-C3 oxo-chain alkyl, C1-C3 chain alkyl, and p is 0 or 1; Optionally, the third group includes the following groups: And R2 includes the following groups: R 21 , R 22 , R 23 , R 24 , R 25 , R 26 Each independently includes a hydrogen atom, a C1-C12 chain alkyl group, and a group represented by E1 to E4, and R 21 , R 22 , R 23 , R 24 , R 25 , R 26 Not all hydrogen atoms at the same time; R 27 Each independently includes C1-C4 chain alkyl; R 28 Each independently includes a C1-C3 chain alkylene group.

4. The dispersant according to claim 2, wherein R1 includes at least one of the second group and the third group; The second group includes R 11 , R 12 , R 13 , R 14 Each independently includes a hydrogen atom, a C2-C8 chain alkyl group, a C3-C8 oxygen chain alkyl group, a C3-C8 sulfur chain alkyl group, and groups represented by A4 to A6, and R 11 , R 12 , R 13 , R 14 At least one of the following comprises the groups shown in A4 to A6; R 15 Each independently includes C1-C3 chain alkyl; R 16 Each independently includes C1-C3 chain alkylene; The third group includes groups shown in B1 to B3, R a Each independently includes one or more of cyano, amino, sulfonic acid and its salt, sulfonic acid ester, phosphate, C1-C3 oxo-chain alkyl, C1-C3 chain alkyl, and p is 0 or 1; Optionally, the third group includes the following groups: And R2 includes the following groups: R 21 , R 22 , R 23 , R 24 , R 25 , R 26 Each independently includes a hydrogen atom, a C1-C12 chain alkyl group, and a group represented by E1 to E4, and R 21 , R 22 , R 23 , R 24 , R 25 , R 26 At least one of includes the groups shown in E1 to E4, R 27 Each independently includes C1-C4 chain alkyl; R 28 Each independently includes a C1-C3 chain alkylene group.

5. The dispersant according to claim 2, wherein R1 includes at least one of the first group and the fourth group; The first group includes a C2-C6 straight chain alkylene group; The fourth group includes groups shown by D1 to D7, R a Each independently includes one or more of cyano, amino, sulfonic acid and its salt, sulfonic acid ester, phosphate, C1-C3 oxo-chain alkyl, C1-C3 chain alkyl, and p is 0 or 1; Optionally, the fourth group includes the following groups: And R2 includes the following groups: R 21 , R 22 , R 23 , R 24 , R 25 , R 26 Each independently includes a hydrogen atom, a C1-C12 chain alkyl group, and a group represented by E1 to E4, and R 21 , R 22 , R 23 , R 24 , R 25 , R 26 At least one of includes the groups shown in E1 to E4, R 27 Each independently includes C1-C4 chain alkyl; R 28 Each independently includes a C1-C3 chain alkylene group.

6. The dispersant according to any one of claims 1 to 5, wherein x represents an integer from 28 to 300, and may be an integer from 58 to 165; and / or, y represents an integer of 15-40, and can be optionally an integer of 25-35.

7. The dispersant according to any one of claims 1 to 6, wherein the number average molecular weight of the dispersant is 20,000-50,000, and can be optionally 20,000-40,000.

8. A method for preparing the dispersant according to any one of claims 1 to 7, comprising the steps of: Provide solvents, catalysts, diisocyanates O=C=N-R1-N=C=O, aliphatic diols HO-R2-OH and polyether diols H-(O-R3) y —OH, the diisocyanate O=C=N—R1—N=C=O, the aliphatic diol HO—R2—OH, the polyether diol H—(O—R3) y —The molar ratio of OH is x:x:1, and the definitions of R1, R2, R3, x, and y are as defined in any one of claims 1 to 7; Adding the solvent, the catalyst, the diisocyanate and the aliphatic diol into a reaction kettle to conduct a stepwise polymerization reaction to obtain an intermediate; Then, the polyether diol is added into the reaction kettle, and the obtained intermediate is allowed to continue to react with the polyether diol, and a dispersant is obtained after the reaction is completed.

9. The method according to claim 8, wherein: In the step of adding the solvent, the catalyst, the diisocyanate and the aliphatic diol into a reaction kettle for a stepwise polymerization reaction, the reaction temperature is 0-80° C.; and / or, The solvent, the catalyst, the diisocyanate and the aliphatic diol are added into a reaction kettle to carry out a stepwise polymerization reaction, and the reaction time is 1-6 hours; and / or, The polyether diol is added into the reaction kettle, and the obtained intermediate and the polyether diol are allowed to react for 2-4 hours.

10. The method according to claim 8 or 9, wherein: The catalyst comprises one or more of methacrylate, phosphonate, organic lead, organic amine, and organic tin; and / or, The weight of the catalyst is 0.3-1.0 wt%, optionally 0.4-0.6 wt%, of the weight of the diisocyanate; and / or, The solvent includes one or more of tetrahydrofuran, N,N-dimethylacetamide, N,N-dimethylformamide, toluene, xylene, acetone, methyl ethyl ketone, cyclohexanone and dioxane.

11. A positive electrode slurry, comprising a solid component and a solvent, wherein the solid component comprises a positive electrode active material, a positive electrode conductor, a positive electrode binder and a dispersant, wherein: The dispersant comprises the dispersant according to any one of claims 1 to 7 or a dispersant prepared by the method according to any one of claims 8 to 10.

12. The positive electrode slurry according to claim 11, wherein: Based on the total weight of the solid component, the content of the dispersant is 0.1-0.5wt%, optionally 0.2-0.3wt%; and / or, Based on the total weight of the solid component, the content of the positive electrode active material is 91.5-99.5wt%; and / or, Based on the total weight of the solid components, the content of the positive electrode conductor is 0.1-4wt%; and / or, Based on the total weight of the solid components, the content of the positive electrode binder is 0.1-4wt%; and / or, The solvent includes an organic solvent, which may optionally include N-methylpyrrolidone; and / or, The solid content of the positive electrode slurry is 50%-75%.

13. A positive electrode sheet, comprising a positive electrode current collector and a positive electrode film layer disposed on at least one surface of the positive electrode current collector, wherein: The positive electrode film layer comprises a positive electrode active material, a positive electrode conductor, a positive electrode binder and a dispersant, wherein the dispersant comprises the dispersant according to any one of claims 1 to 7 or a dispersant prepared by the method according to any one of claims 8 to 10.

14. The positive electrode sheet according to claim 13, wherein: Based on the total weight of the positive electrode film layer, the content of the dispersant is 0.1-0.5wt%, optionally 0.2-0.3wt%; and / or, Based on the total weight of the positive electrode film layer, the content of the positive electrode active material is 91.5-99.5wt%; and / or, Based on the total weight of the positive electrode film layer, the content of the positive electrode conductive agent is 0.1-4wt%; and / or, Based on the total weight of the positive electrode film layer, the content of the positive electrode binder is 0.1-4wt%; and / or, The positive electrode active material is capable of extracting and inserting lithium ions or sodium ions.

15. A method for preparing the positive electrode sheet according to claim 13 or 14, comprising the steps of: coating the positive electrode slurry according to any one of claims 11 to 12 on a positive electrode current collector, and obtaining the positive electrode sheet after drying and rolling.

16. A method for preparing the positive electrode sheet according to claim 13 or 14, comprising the steps of: Mixing a positive electrode conductive agent, a positive electrode binder, a dispersant and a solvent to form a conductive slurry; kneading the positive electrode active material and the conductive slurry to form a mass-like material; The obtained mass material is formed into a film by extrusion or hot pressing; The obtained film is rolled and thinned, then composited with the positive electrode current collector, and dried to obtain the positive electrode sheet.

17. The method according to claim 16, wherein: The solid content of the conductive paste is 3-20%; and / or, The solid content of the agglomerated material is 70%-95%.

18. A battery cell comprising the positive electrode sheet according to claim 13 or 14, or a positive electrode sheet prepared by the method according to any one of claims 15 to 17.

19. The battery cell according to claim 18, wherein: The battery cells include one or more of lithium-ion battery cells, lithium metal battery cells, sodium-ion battery cells, and sodium metal battery cells.

20. A battery comprising the battery cell according to claim 18 or 19.

21. An electrical device comprising the battery according to claim 20.

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