Dispersants and methods for making the same, slurry compositions and methods for making the same, electrode sheets and devices comprising the same

Abstract

The present application provides a dispersant, a preparation method thereof, a slurry composition, a preparation method thereof, an electrode sheet, and an electric device comprising the electrode sheet, the dispersant comprising a block copolymer having a first block and a second block, the first block comprising a first repeating structural unit represented by formula I) and a second repeating structural unit represented by formula II), and the second block comprising a third repeating structural unit represented by formula III) and a fourth repeating structural unit represented by formula IV), wherein n is any one integer from 1 to 25, R1-R7 are independently selected from hydrogen, halogen, cyano, carbonyl, carboxyl, nitro, sulfonic acid group, amide, ester group, substituted or unsubstituted C1-C15 alkyl and alkoxy, and substituted or unsubstituted C6-C30 aryl, R8, R9, R 10 The dipole moment of the formula I) is greater than 2×10 ‑30 C·m. The dispersant can improve the stability of the slurry.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a dispersant and its preparation method, a slurry composition and its preparation method, an electrode sheet, and an apparatus including the electrode sheet. Background Technology

[0002] Batteries, due to their advantages such as high energy density, rechargeability, and good cycle performance, are widely used in electrical devices such as mobile phones, tablets, laptops, and electric vehicles. With the development of battery technology, increasingly higher performance requirements are being placed on batteries, such as cycle performance. The stability of electrode slurry has a crucial impact on battery performance; therefore, improving the stability of electrode slurry is a pressing issue in battery technology. Summary of the Invention

[0003] This application provides a dispersant and its preparation method, a slurry composition and its preparation method, an electrode sheet, and an electrical device including the electrode sheet, which can improve the stability of the slurry.

[0004] In a first aspect, embodiments of this application provide a dispersant comprising a block copolymer having a first block and a second block;

[0005] The first block includes a first repeating structural unit as shown in Equation I) and a second repeating structural unit as shown in Equation II):

[0006] R1, R2, R3, R4, R5, R6 and R7 are each independently selected from hydrogen, halogen, cyano, carbonyl, carboxyl, nitro, sulfonic acid, amide, ester, substituted or unsubstituted C1-C15 alkyl, substituted or unsubstituted C1-C15 alkoxy, substituted or unsubstituted C6-C30 aryl.

[0007] The second block includes a third repeating structural unit as shown in Formula III) and a fourth repeating structural unit as shown in Formula IV:

[0008] Wherein, the average degree of polymerization n is any integer from 1 to 25, R8, R9, R 10 The dipole moment is greater than 2 × 10 -30 C·m;

[0009] Optionally, R8, R9, R 10 Each group is independently selected from hydroxyl, carboxyl, pyrrolidone, ethylene oxide, propylene oxide, halogen, substituted or unsubstituted C1-C15 alkyl, substituted or unsubstituted C1-C15 alkoxy, wherein R9 and R 10They can be connected together as R9-OR 10 Or R9-NH-R 10 .

[0010] In the above embodiments, the dispersant is a block copolymer having a first block and a second block, wherein the first block includes a first repeating structural unit having a first repeating structural unit having a second repeating structural unit having a first repeating structural unit having a third repeating structural unit having a third repeating structural unit having a third repeating structural unit having a fourth ...

[0011] In some embodiments of the application, R1, R2, R3, R4, R5, R6, and R7 are each independently selected from hydrogen, halogen, cyano, substituted or unsubstituted C1-C12 alkyl, and substituted or unsubstituted C6-C12 aryl. Optionally, R1, R2, R3, R4, R5, R6, and R7 are each independently selected from at least one of hydrogen, halogen, cyano, methyl, ethyl, propyl, butyl, pentyl, n-hexyl, phenyl, and benzyl.

[0012] In the above embodiments, R1, R2, R3, R4, R5, R6 and R7 are each independently selected from the above-mentioned groups, which can make the dispersant help to uniformly disperse the active material and conductive agent and other components, and can also improve the conductivity of the slurry, thereby reducing the resistance of the electrode sheet having the slurry.

[0013] In some embodiments of this application, the first repeating structural unit has the following structural formula:

[0014] The second repeating structural unit is ethylene.

[0015] In the above embodiments, the first repeating structural unit has the above-described structural formula, and the second repeating structural unit is ethylene, which can help disperse solid particles in the slurry.

[0016] In some embodiments of this application, the first block is a random copolymer block of the first repeating structural unit and the second repeating structural unit.

[0017] In the above embodiments, the first block is a random copolymer block of the first repeating structural unit and the second repeating structural unit, which can reduce the difficulty of preparing the dispersant.

[0018] In some embodiments of this application, the weight-average molecular weight of the first block is in the range of 1,000-500,000.

[0019] In the above embodiments, the weight-average molecular weight of the first block is within the above range, which can help to uniformly disperse solid particles in the slurry and increase the solid content in the slurry.

[0020] In some embodiments of this application, the weight-average molecular weight of the second block is in the range of 1,000-500,000.

[0021] In the above embodiments, the weight-average molecular weight of the second block is within the above range, which can reduce the agglomeration of components in the slurry and also help to achieve uniform dispersion of each component in the slurry.

[0022] In some embodiments of this application, the average degree of polymerization ratio of the first block and the second block is (0.1-10):1.

[0023] In the above embodiments, the average degree of polymerization of the first block and the second block is within the above range, which can improve the dispersion effect of each component in the slurry and further increase the solid content in the slurry, so that the slurry has better stability.

[0024] Secondly, embodiments of this application provide a method for preparing the dispersant as described in any of the foregoing embodiments, comprising:

[0025] The initiator and chain transfer agent were dissolved in an organic solvent and stirred under an inert atmosphere to obtain a mixed solution;

[0026] A first copolymerization reaction is carried out by adding a monomer with a first block to the mixed solution;

[0027] After the first copolymerization reaction is completed, the monomer of the second block is added to carry out the second copolymerization reaction;

[0028] After the second copolymerization reaction is completed, the resulting product is precipitated, filtered, and dried to obtain the dispersant.

[0029] In the above embodiments, the preparation process is simple and safe. The prepared dispersant dissolves in the solvent, which helps to uniformly disperse other components in the slurry, increases the solid content in the slurry, and thus improves the stability of the slurry.

[0030] In some embodiments of this application, the stirring rate is in the range of 20 min / rpm to 1500 min / rpm.

[0031] In the above embodiments, stirring rates within the aforementioned range can help the initiator and chain transfer agent dissolve in the solvent, facilitating the occurrence of the first copolymerization reaction and the second copolymerization reaction.

[0032] In some embodiments of this application, the reaction temperature of the first copolymerization reaction is between -20°C and 120°C.

[0033] In the above embodiments, the reaction temperature of the first copolymerization reaction is within the above range, which can improve the yield of the product in the first copolymerization reaction.

[0034] Thirdly, embodiments of this application provide a slurry composition for forming an electrode film layer, comprising the dispersant described in any of the above embodiments, as well as a binder, an active material, and an optional conductive agent.

[0035] In the above embodiments, the slurry composition has a high solid content because it includes the dispersant in the above embodiments, and the resulting slurry has good stability, which helps to improve the performance of the battery.

[0036] In some embodiments of this application, the slurry composition comprises, by a total mass fraction of 100%, the following:

[0037] Dispersant, 0.01%-10%;

[0038] Adhesive, 0.5%-10%;

[0039] Active materials, 82%-91.99%;

[0040] Conductive agent, 0%-15%.

[0041] In the above embodiments, the stability of the slurry can be further improved by rationally selecting the content of each component.

[0042] In some embodiments of this application, the active material is a positive electrode active material.

[0043] In the above embodiments, the dispersant can be adsorbed onto the surface of the positive electrode active material, making it uniformly dispersed, thereby further improving the performance of the battery.

[0044] Fourthly, embodiments of this application provide a method for preparing the slurry composition described in any of the above embodiments, comprising:

[0045] The conductive agent, dispersant, and a portion of the solvent are mixed under stirring conditions to obtain a first mixture;

[0046] The adhesive is added to the first mixture and stirred to obtain the second mixture;

[0047] The active material and the remaining solvent are added to the second mixture and stirred to obtain the slurry composition.

[0048] In these embodiments, pulping efficiency is improved by optimizing the order of component addition.

[0049] Fifthly, embodiments of this application provide an electrode sheet, comprising:

[0050] current collector;

[0051] An active material layer is disposed on at least one surface of the current collector, the active material layer being formed using the slurry composition described in any of the above embodiments.

[0052] In the above embodiments, since the active material layer of the electrode sheet uses the slurry composition of the above embodiments, the electrode sheet has a lower resistance and can improve the cycle performance of the battery.

[0053] Sixthly, embodiments of this application provide a secondary battery, comprising:

[0054] Positive electrode sheet;

[0055] Negative electrode plate;

[0056] A diaphragm is disposed between the positive electrode and the negative electrode;

[0057] Wherein, the positive electrode and / or the negative electrode are the electrode plates described in the above embodiments.

[0058] In the above embodiments, since the positive electrode and / or negative electrode are the same as the electrode plates in the above embodiments, the battery has good cycle performance.

[0059] In a seventh aspect, embodiments of this application provide a battery module, including the secondary battery described in the above embodiments.

[0060] In the above embodiments, since the secondary battery in the above embodiments is included, the battery module also has the technical effects of the secondary battery, which will not be elaborated here.

[0061] Eighthly, embodiments of this application provide a battery pack, including the secondary battery or the battery module described in the above embodiments.

[0062] In the above embodiments, since the secondary battery or battery module in the above embodiments is included, the battery pack also has the technical effects of the secondary battery or battery module, which will not be elaborated here.

[0063] Ninthly, embodiments of this application provide an electrical device, including the secondary battery, the battery module, or the battery pack described in the above embodiments.

[0064] In the above embodiments, since the device includes the secondary battery, battery module or battery pack described in the above embodiments, it has a long service life and driving range. Attached Figure Description

[0065] To more clearly illustrate the embodiments of this application, the accompanying drawings used in the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the drawings without creative effort.

[0066] Figure 1 The present application provides structural schematic diagrams of vehicles according to some embodiments;

[0067] Figure 2 The present application shows a schematic diagram of the structure of a battery pack provided in some embodiments;

[0068] Figure 3 It shows Figure 2 Exploded view of the battery pack;

[0069] Figure 4 It shows Figure 3 A schematic diagram of the structure of the battery module;

[0070] Figure 5 The present application provides schematic diagrams of the structure of a single battery cell according to some embodiments.

[0071] Figure 6 It shows Figure 5 A schematic diagram of the exploded structure of a single battery cell.

[0072] The accompanying drawings are not drawn to scale.

[0073] Marker explanation:

[0074] 1000 vehicles;

[0075] Battery pack 100, controller 200, motor 300;

[0076] First box 11, second box 12;

[0077] Battery module 20;

[0078] Battery cell 30, casing 31, electrode assembly 32, cover assembly 33. Detailed Implementation

[0079] The embodiments of this application will now be described in detail with reference to the accompanying drawings. These embodiments are merely illustrative and should not be construed as limiting the scope of protection of this application.

[0080] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0081] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0082] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0083] In the description of the embodiments of this application, unless otherwise stated, "above" and "below" include the number itself, and "multiple" and "one or more" in "one or more" mean two or more.

[0084] In the description of the embodiments in this application, the terms "a" and "the" refer to one or more molecules of the compound, and are not limited to a single molecule of the compound. Furthermore, the one or more molecules may be the same or different, as long as they fall within the category of the chemical compound.

[0085] The grouping of alternative elements or embodiments disclosed herein should not be construed as limiting. Each member of a group may be adopted and claimed individually, or in any combination with other members of that group or other elements found herein. It is foreseeable that one or more members of a group may be included in or removed from the group for convenience and / or patentability reasons. When any such inclusion or removal occurs, the specification herein is regarded as containing the modified group and thus satisfying the written description of the entire Markush group as used in the claims.

[0086] Various modifications and variations can be made to this application without departing from its scope of protection, which will be obvious to those skilled in the art. Therefore, this application is intended to cover modifications and variations falling within the scope of the corresponding claims (the claimed scope) and their equivalents. It should be noted that the implementation methods provided in the embodiments of this application can be combined with each other without contradiction.

[0087] Before explaining the scope of protection provided by the embodiments of this application, in order to facilitate the understanding of the embodiments of this application, this application first specifically describes the problems existing in the related technology.

[0088] Batteries are widely used in electrical devices such as mobile phones, tablets, laptops, and electric vehicles due to their advantages such as high energy density, rechargeability, and good cycle performance. With the development of battery technology, increasingly higher performance requirements are being placed on batteries, such as cycle performance.

[0089] The stability of electrode slurry has a crucial impact on battery performance. Currently, lipophilic dispersants, such as polyvinyl alcohol and polyethylene glycol, are typically added to the slurry to improve the dispersion of solid components in organic solvents, thereby enhancing slurry stability. However, the inventors have found that these dispersants offer limited improvement in slurry stability, resulting in a poor effect on battery performance enhancement.

[0090] In view of this, this application provides a dispersant and a method for preparing the same, a slurry composition and a method for preparing the same, an electrode sheet, and an electrical device including the electrode sheet, which can improve the stability of the slurry.

[0091] In this application, the electrical device can be, but is not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, spacecraft, etc. Electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0092] For ease of explanation, the following embodiments will be described using a vehicle 1000 as an example of an electrical device according to an embodiment of this application.

[0093] Figure 1 A schematic diagram of the structure of a vehicle provided in some embodiments of this application is shown.

[0094] like Figure 1Vehicle 1000 can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. A battery pack 100 is installed inside vehicle 1000, which can be located at the bottom, front, or rear of vehicle 1000. The battery pack 100 can be used to power vehicle 1000; for example, it can serve as the operating power source for vehicle 1000. Vehicle 1000 may also include a controller 200 and a motor 300. The controller 200 controls the battery pack 100 to supply power to the motor 300, for example, to meet the power needs of vehicle 1000 during starting, navigation, and driving.

[0095] In some embodiments of this application, the battery pack 100 can not only serve as the operating power source for the vehicle 1000, but also as the driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0096] Figure 2 A schematic diagram of the structure of a battery pack provided in some embodiments of this application is shown. Figure 3 It shows Figure 2 A schematic diagram of the exploded structure of the battery pack.

[0097] In this application, battery pack 100 refers to a device comprising at least one battery module 20 or at least one battery cell 30. Figure 2 and Figure 3 The battery pack 100 includes a housing and a battery module 20, with the battery module 20 housed within the housing.

[0098] The battery pack 100 includes a housing and a battery module 20, with the battery module 20 housed within the housing. The housing provides a space for the battery module 20 and can have various structures. In some embodiments, the housing may include a first housing 11 and a second housing 12, which overlap each other, collectively defining a space for accommodating the battery module 20. The second housing 12 may be a hollow structure with one open end, while the first housing 11 may be a plate-like structure, covering the open side of the second housing 12 so that the first housing 11 and the second housing 12 together define the space. Alternatively, both the first housing 11 and the second housing 12 may be hollow structures with one open end, with the open side of the first housing 11 covering the open side of the second housing 12. Of course, the housing formed by the first housing 11 and the second housing 12 can have various shapes, such as a cylinder or a cuboid.

[0099] In the battery pack 100, there can be multiple battery modules 20. These multiple battery modules 20 can be connected in series, in parallel, or in a mixed configuration. A mixed configuration means that multiple battery modules 20 are connected in both series and parallel configurations. Multiple battery modules 20 can be directly connected in series, in parallel, or in a mixed configuration together, and then the entire assembly of the multiple battery modules 20 is housed within a housing.

[0100] Figure 4 It shows Figure 3 A schematic diagram of the battery module.

[0101] The battery module 20 includes one or more individual battery cells 30. For example, such as Figure 4 As shown, the battery module 20 includes multiple battery cells 30, which can be connected in series, parallel, or in a mixed manner. A mixed connection means that some of the battery cells 30 are connected in series and others in parallel. The multiple battery cells 30 can be directly connected in series, parallel, or in a mixed manner together.

[0102] Each battery cell 30 can be a secondary battery cell or a primary battery cell; it can also be a lithium-ion battery, sodium-ion battery, magnesium-ion battery, or potassium-ion battery, but is not limited to these. The battery cell 30 can be cylindrical, flat, cuboid, or other shapes.

[0103] Figure 5 A schematic diagram of the structure of a battery cell provided in some embodiments of this application is shown. Figure 6 It shows Figure 5 A schematic diagram of the exploded structure of a single battery cell.

[0104] As shown in Figure 5, the battery cell 30 refers to the smallest unit that makes up the battery. Figure 6 As shown, the battery cell 30 includes a housing 31, an electrode assembly 32, and a cover assembly 33. The housing 31 has a chamber for accommodating the electrode assembly 32, and the cover assembly 33 is used to close the opening of the housing 31. The cover assembly 33 includes an end cap, which is connected to the housing 31 to form the outer shell of the battery cell 30. The electrode assembly 32 is disposed inside the housing 31, and the housing 31 is filled with electrolyte.

[0105] An end cap is a component that covers the opening of the housing 31 to isolate the internal environment of the battery cell 30 from the external environment. The shape of the end cap can be adapted to the shape of the housing 31 to fit it. Optionally, the end cap can be made of a material with a certain hardness and strength (such as aluminum alloy), so that the end cap is less prone to deformation under pressure and impact, giving the battery cell 30 higher structural strength and improved safety performance. Functional components such as electrode terminals can be provided on the end cap. The electrode terminals can be used to electrically connect to the electrode assembly 32 for outputting or inputting electrical energy into the battery cell 30. In some embodiments, the end cap can also be provided with a pressure relief mechanism for releasing internal pressure when the internal pressure or temperature of the battery cell 30 reaches a threshold. The material of the end cap can also be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and this application embodiment does not impose any special limitations on this. In some embodiments, an insulating element may be provided on the inner side of the end cap. The insulating element can be used to isolate the electrical connection components within the housing 31 from the end cap to reduce the risk of short circuits. Exemplarily, the insulating element may be made of plastic, rubber, etc.

[0106] The housing 31 is an assembly used to cooperate with the end cap to form the internal environment of the battery cell 30, wherein the formed internal environment can accommodate the electrode assembly 32, electrolyte, and other components. The housing 31 and the end cap can be independent components, with an opening provided on the housing 31. The end cap closes the opening to form the internal environment of the battery cell 30. Alternatively, the end cap and housing 31 can be integrated. Specifically, the end cap and housing 31 can form a common connecting surface before other components are inserted into the housing, and the end cap closes the housing 31 when it is necessary to encapsulate the interior. The housing 31 can be of various shapes and sizes, such as cuboid, cylindrical, hexagonal prism, etc.

[0107] Electrode assembly 32 is the component in the battery cell 30 where electrochemical reactions occur. The casing 31 may contain one or more electrode assemblies 32. The electrode assembly 32 is mainly formed by winding or stacking positive and negative electrode sheets, and typically a separator is provided between the positive and negative electrode sheets. The portions of the positive and negative electrode sheets containing active material constitute the main body of the electrode assembly 32, while the portions without active material each constitute a tab. The positive and negative tabs may be located together at one end of the main body or separately at both ends of the main body. During the charging and discharging process of the battery, the positive and negative active materials react with the electrolyte, and the tabs connect to the electrode terminals to form a current loop.

[0108] Dispersant for secondary batteries

[0109] This application provides a dispersant comprising a block copolymer having a first block and a second block, wherein the first block comprises a first repeating structural unit having a first repeating structural unit having a second ...

[0110] R1, R2, R3, R4, R5, R6 and R7 are each independently selected from hydrogen, halogen, cyano, carbonyl, carboxyl, nitro, sulfonic acid, amide, ester, substituted or unsubstituted C1-C15 alkyl, substituted or unsubstituted C1-C15 alkoxy, substituted or unsubstituted C6-C30 aryl.

[0111] The second block includes a third repeating structural unit as shown in equation (III) and a fourth repeating structural unit as shown in equation (IV):

[0112] Wherein, the average degree of polymerization n is any integer from 1 to 25, R8, R9, R 10 The dipole moment is greater than 2 × 10 -30 C·m.

[0113] In this application, halogen refers to fluorine, chlorine, bromine, or iodine.

[0114] In this application, when a compound or chemical structural feature (e.g., alkyl, aryl) is referred to as "substituted," that feature may have one or more substituents. The term "substituent" has the broadest meaning known to those skilled in the art and includes a moiety that occupies a position normally occupied by one or more hydrogen atoms attached to the parent compound or chemical structural feature.

[0115] In this application, the term "C1-C15 alkyl" refers to a straight-chain or branched alkyl group having 1 to 15 carbon atoms. Examples of alkyl groups include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, 1-methylbutyl, 2-methylbutyl, isopentyl, 1-ethylpropyl, 1,1-dimethylpropyl, 1,2-dimethylpropyl, neopentyl, n-hexyl, 1-methylpentyl, 2-methylpentyl, 3-methylpentyl, isohexyl, 1-ethylbutyl, 2-ethylbutyl, 1,1-dimethylbutyl, 1,2-dimethylbutyl, 1,3-dimethylbutyl, 2,2-dimethylbutyl, 2,3-dimethylbutyl, 3,3-dimethylbutyl, 1,1,2-trimethylpropyl, 1,2,2-trimethylpropyl, or 1-ethyl-1-methylpropyl.

[0116] In this application, the term "C6-C30 aryl" refers to a closed aromatic ring or ring system having 6 to 30 carbon atoms. Examples of aryl groups include, but are not limited to, phenyl, naphthyl, phenanthryl, anthracene, biphenyl (including diphenyl and terphenyl), triphenylene, pyrene, spirobisfluorene, etc. It includes alkyl, peryl, indole, azulele, and benzo[a]phenanthrene.

[0117] In this application, the term "sterically hindered group" refers to any functional group capable of creating mutual repulsion in spatial arrangement. Such sterically hindered groups include, but are not limited to, hydroxyl, alkoxy, and cycloalkoxy groups.

[0118] In this application, the term "C1-C15 alkoxy group" refers to a straight-chain or branched C1-C15 alkyl group, or a cycloalkyl group having 1 to 15 carbon atoms, wherein in each case there are one or more oxygen atoms between two carbon atoms. Alkoxy groups include, but are not limited to, methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, sec-butoxy, tert-butoxy, pentoxy, hexoxy, heptoxy, octoxy, nonoxy, decoxy, undecoxy, dodecoxy, tridecoxy, tetradecoxy, pentadecoxy, ethylene oxide, propylene oxide, hexyl oxide, and octyl oxide.

[0119] In the above embodiments, the dispersant is a block copolymer having a first block and a second block, wherein the first block includes a first repeating structural unit having a first repeating structural unit having a first repeating structural unit having a second repeating structural unit having a third repeating structural unit having a third repeating structural unit having a third repeating structural unit having a fourth repeating structural unit having a fourth repeating structural unit having a third ... third repeating structural unit having a fourth repeating structural unit having a third repeating structural unit having a third repeating structural unit having a third repeating structural unit having a third repeating structural unit having a third repeating structural unit having a fourth repeating structural unit having a third repeating structural unit having a third repeating structural unit having a third repeating structural unit having a third repeating structural unit having a third repeating structural unit having a fourth repeating structural unit having a third repeating structural unit having a third repeating structural unit having a third repeating structural unit having a fourth repeating structural unit having a third repeating structural unit having a third repeating structural unit having a fourth repeating structural unit having a third repeating structural unit having a third repeating structural unit having a fourth repeating structural unit having a third repeating structural unit having a third repeating structural unit having a fourth repeating structural unit having a third repeating structural unit having a fourth repeating structural unit having a

[0120] In some embodiments of the application, R1, R2, R3, R4, R5, R6 and R7 are each independently selected from hydrogen, halogen, cyano, substituted or unsubstituted C1-C12 alkyl, substituted or unsubstituted C6-C12 aryl.

[0121] In the above embodiments, R1, R2, R3, R4, R5, R6, and R7 are each independently selected from the aforementioned groups, which allows the dispersant to dissolve rapidly in the organic solvent and adsorb onto the surface of solid particles in the slurry, thereby contributing to the uniform dispersion of solid particles and further increasing the solid content in the slurry. Moreover, the uniform dispersion of each component in the slurry can also improve the conductivity of the slurry, thereby reducing the resistance of the electrode sheet containing the slurry.

[0122] In some specific embodiments of this application, R1, R2, R3, R4, R5, R6 and R7 are each independently selected from at least one of hydrogen, halogen, cyano, methyl, ethyl, propyl, butyl, pentyl, n-hexyl, phenyl and benzyl.

[0123] In the above embodiments, R1, R2, R3, R4, R5, R6 and R7 are each independently selected from at least one of hydrogen, halogen, cyano, methyl, ethyl, propyl, butyl, pentyl, n-hexyl, phenyl and benzyl, which helps to further increase the solid content in the slurry and reduce the resistance of the electrode sheet having the slurry.

[0124] In some embodiments of this application, when R1, R2, R3, R4, and R5 are each selected from hydrogen, the first repeating structural unit has the structural formula (V):

[0125] When R6 and R7 are both selected from hydrogen, the second repeating structural unit is ethylene.

[0126] In the above embodiments, the first repeating structural unit has the above-described structural formula, and the second repeating structural unit is ethylene, which can help the dispersant to be firmly adsorbed on the surface of solid particles in the slurry, so that the solid particles are uniformly dispersed.

[0127] In some embodiments of this application, the first block is a random copolymer block of a first repeating structural unit and a second repeating structural unit.

[0128] In the above embodiments, the first block is a random copolymer block of the first repeating structural unit and the second repeating structural unit, which can reduce the difficulty of preparing the dispersant.

[0129] In some embodiments of this application, the weight-average molecular weight of the first block is in the range of 1,000-500,000.

[0130] In the above embodiments, the weight-average molecular weight of the first block is within the above range, which can help to uniformly disperse solid particles in the slurry and increase the solid content in the slurry.

[0131] For example, the weight-average molecular weight of the first block can be 1000, 2000, 3000, 4000, 5000, 6000, 7000, 8000, 9000 or higher.

[0132] In the embodiments of this application, the second block includes a third repeating structural unit as shown in Formula III) and a fourth repeating structural unit as shown in Formula IV). The third repeating structural unit as shown in Formula III) can be used as a steric hindrance group to randomly copolymerize with the fourth repeating structural unit as shown in Formula IV to form a random copolymer block. This can result in greater steric hindrance between dispersant molecules and reduce the agglomeration of components in the slurry.

[0133] In some embodiments of this application, R8 is selected from hydroxyl, carboxyl, pyrrolidone, ethylene oxide, propylene oxide, halogen, substituted or unsubstituted C1-C15 alkyl, substituted or unsubstituted C1-C15 alkoxy.

[0134] In the above embodiments, R8 is selected from the above-mentioned groups, which gives the dispersant molecules greater steric hindrance and reduces the occurrence of component agglomeration in the slurry.

[0135] In some embodiments of this application, R9, R 10 Each group is independently selected from hydroxyl, carboxyl, pyrrolidone, ethylene oxide, propylene oxide, halogen, substituted or unsubstituted C1-C15 alkyl, substituted or unsubstituted C1-C15 alkoxy, wherein R9 and R 10 They can be connected together as R9-OR 10 Or R9-NH-R 10 .

[0136] In the above embodiments, R9 and R 10 Selected from the above-mentioned groups, the dispersant molecules can have greater steric hindrance, while also enabling the dispersant to help improve the dispersion effect of each component in the slurry.

[0137] In some embodiments of this application, the weight-average molecular weight of the second block is in the range of 1,000-500,000.

[0138] In the above embodiments, the weight-average molecular weight of the second block is within the above range, which can reduce the agglomeration of components in the slurry and also help to achieve uniform dispersion of each component in the slurry.

[0139] For example, the weight-average molecular weight of the second block can be 1000, 2000, 3000, 4000, 5000, 6000, 7000, 8000, 9000 or higher.

[0140] In some embodiments of this application, the average degree of polymerization ratio of the first block and the second block is (0.1-10):1.

[0141] In the above embodiments, the average degree of polymerization of the first block and the second block is within the above range, which can improve the dispersion effect of each component in the slurry and further increase the solid content in the slurry, so that the slurry has better stability.

[0142] Preparation of dispersants

[0143] This application provides a method for preparing a dispersant as described in any of the above embodiments, comprising:

[0144] S10: Dissolve the initiator and chain transfer agent in an organic solvent and stir under an inert atmosphere to obtain a mixed solution;

[0145] S20: Add the monomer of the first block to the mixed solution to carry out the first copolymerization reaction;

[0146] S30: After the first copolymerization reaction is completed, add the monomer of the second block to carry out the second copolymerization reaction;

[0147] S40: After the second copolymerization reaction is completed, the product is precipitated, filtered, and dried to obtain a dispersant.

[0148] In the above embodiments, the preparation process is simple and safe. The prepared dispersant dissolves in the solvent, which helps to uniformly disperse other components in the slurry, increases the solid content in the slurry, and thus improves the stability of the slurry.

[0149] In some embodiments of this application, the stirring rate in step S10 is in the range of 20 min / rpm to 1500 min / rpm.

[0150] In the above embodiments, the stirring linear speed is within the above range, which helps the initiator and chain transfer agent dissolve in the solvent, facilitating the occurrence of the first copolymerization reaction and the second copolymerization reaction.

[0151] In some embodiments of this application, the reaction temperature of the first copolymerization reaction in step S20 is between -20°C and 120°C.

[0152] In the above embodiments, the reaction temperature of the first copolymerization reaction is within the above range, which can improve the yield of the product in the first copolymerization reaction.

[0153] In some embodiments of this application, the initiator can be any one or more initiators used for copolymerization reactions, such as azo compounds. For example, the initiator can be, but is not limited to, azobisisobutyronitrile (AIBN).

[0154] In some embodiments of this application, the chain transfer agent can be any one or more chain transfer agents used in copolymerization reactions, and this application does not impose specific limitations on this. For example, the chain transfer agent can have the structural formula of formula VI):

[0155] Among them, R 11 Alkyl groups selected from C1-C5.

[0156] Slurry composition for forming electrode film layer

[0157] This application provides a slurry composition for forming an electrode film, comprising the dispersant, binder, active material, and optional conductive agent as described in any of the above embodiments.

[0158] In the above embodiments, the slurry composition has a high solid content because it includes the dispersant in the above embodiments, and the resulting slurry has good stability, which helps to improve the performance of the battery.

[0159] In some embodiments of this application, the adhesive may include, but is not limited to, at least one of sodium polyacrylate, polyacrylamide, polyacrylic acid, polyacrylate, polyacrylonitrile, styrene-butadiene rubber, polytetrafluoroethylene, polyvinylidene fluoride, and polyvinyl alcohol.

[0160] In some embodiments of this application, the conductive agent may include, but is not limited to, at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0161] In some embodiments of this application, the slurry composition comprises, by a total mass fraction of 100%, the following:

[0162] Dispersant, 0.01%-10%;

[0163] Adhesive, 0.5%-10%;

[0164] Active materials, 82%-91.99%;

[0165] Conductive agent, 0%-15%.

[0166] In the above embodiments, the stability of the slurry can be further improved by rationally selecting the content of each component.

[0167] In some embodiments of this application, the active material is a positive electrode active material, which can be any one or more positive electrode active materials used in batteries.

[0168] For example, the positive electrode active material may include at least one of the following materials: lithium phosphates with an olivine structure, lithium transition metal oxides, and their respective modified compounds. However, this application is not limited to these materials, and other conventional materials that can be used as battery positive electrode active materials may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium transition metal oxides may include, but are not limited to, lithium cobalt oxides (such as LiCoO2), lithium nickel oxides (such as LiNiO2), lithium manganese oxides (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxides, lithium manganese cobalt oxides, lithium nickel manganese oxides, and lithium nickel cobalt manganese oxides (such as 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 Co 0.2 Mn 0.2 O2 (abbreviated as NCM622), LiNi 0.8 Co 0.1 Mn 0.1 O2 (abbreviated as NCM811), lithium nickel cobalt aluminum oxide (such as LiNi) 0.85 Co 0.15 Al 0.05 At least one of O2 and its modified compounds. Examples of lithium phosphates with an olivine structure include, but are not limited to, lithium iron phosphate (such as LiFePO4, also known as LFP), lithium iron phosphate and carbon composites, lithium manganese phosphate (such as LiMnPO4), lithium manganese phosphate and carbon composites, lithium manganese iron phosphate, and lithium manganese iron phosphate and carbon composites.

[0169] In some other embodiments of this application, the active material may also be a negative electrode active material, which may be any one or more negative electrode active materials used in batteries.

[0170] For example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate, etc. Silicon-based materials may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. Tin-based materials may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, this application is not limited to these materials, and other conventional materials that can be used as battery negative electrode active materials may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0171] In the above embodiments, the dispersant can be adsorbed onto the surface of the positive electrode active material, making it uniformly dispersed, thereby further improving the performance of the battery.

[0172] Preparation of slurry composition

[0173] This application provides a method for preparing a slurry composition, comprising:

[0174] S50: The conductive agent, dispersant and a portion of the solvent are mixed under stirring conditions to obtain a first mixture;

[0175] S60: Add the adhesive to the first mixture and stir to obtain the second mixture;

[0176] S70: Add the active material and the remaining solvent to the second mixture and stir to obtain a slurry composition.

[0177] In these embodiments, pulping efficiency is improved by optimizing the order of component addition.

[0178] In the embodiments of this application, the stirring linear velocity and stirring time of the slurry can be reduced by using the dispersant described in the above embodiments. In some embodiments of this application, the stirring linear velocity in step S50 is 2 m / s-10 m / s, and the stirring time is 5 min-40 min; the stirring linear velocity in step S60 is 2 m / s-10 m / s, and the stirring time is 5 min-40 min; the stirring linear velocity in step S70 is 2 m / s-10 m / s, and the stirring time is 150 min-220 min.

[0179] Electrode plates

[0180] This application provides an electrode sheet including a current collector and an active material layer, wherein the active material layer is disposed on at least one surface of the current collector, and the active material layer is formed using the slurry composition in any of the above embodiments.

[0181] In the above embodiments, since the active material layer of the electrode sheet uses the slurry composition of the above embodiments, the electrode sheet has a lower resistance and can improve the cycle performance of the battery.

[0182] In some embodiments of this application, the current collector may be a metal foil or a composite current collector. For example, aluminum foil may be used as the metal foil. The composite current collector may include a polymer material substrate and a metal layer formed on at least one surface of the polymer material substrate. The composite current collector may be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0183] Secondary batteries

[0184] This application provides a secondary battery, including a positive electrode, a negative electrode, and a separator. The separator is disposed between the positive and negative electrode. The positive and / or negative electrode are the electrode plates described in the above embodiments.

[0185] In the above embodiments, since the positive electrode and / or negative electrode are the same as the electrode plates in the above embodiments, the battery has good cycle performance.

[0186] In some embodiments of this application, the positive electrode sheet is the electrode sheet in the above embodiments, and the active material layer is the positive electrode active material layer. This positive electrode sheet can be prepared by coating the above-described positive electrode slurry composition onto at least one surface of the positive electrode current collector, drying, and cold pressing to obtain the positive electrode sheet.

[0187] In some embodiments of this application, the negative electrode sheet is the electrode sheet in the above embodiments, and the active material layer is the negative electrode active material layer. This negative electrode sheet can be prepared by coating the above-mentioned negative electrode slurry composition onto at least one surface of the negative electrode current collector, drying, and cold pressing to obtain the negative electrode sheet.

[0188] This application does not impose any particular restrictions on the type of diaphragm; any one or more porous diaphragms with good chemical and mechanical stability can be used.

[0189] In some embodiments of this application, the diaphragm material may be selected from at least one of glass fiber, nonwoven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The diaphragm may be a single-layer film or a multi-layer composite film, without particular limitation. When the diaphragm is a multi-layer composite film, the materials of each layer may be the same or different, without particular limitation.

[0190] In embodiments of this application, an electrolyte is also included, which acts as a conductor of ions between the positive and negative electrode plates. This application does not impose specific limitations on the type of electrolyte; it can be selected according to requirements. For example, the electrolyte can be liquid, gel-like, or entirely solid.

[0191] In some embodiments of this application, the electrolyte is liquid and includes an electrolyte salt and a solvent.

[0192] In some embodiments of this application, the electrolyte salt may be selected from at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalate borate, lithium dioxalate borate, lithium difluorodioxalate phosphate, and lithium tetrafluorooxalate phosphate.

[0193] In some embodiments of this application, the solvent may be selected from at least one of ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butyl carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, ethylene carbonate, sulfolane, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone.

[0194] In some embodiments of this application, the electrolyte may optionally include additives. As examples, additives may include negative electrode film-forming additives, positive electrode film-forming additives, and may also include additives that can improve certain battery performance, such as additives that improve battery overcharge performance, additives that improve battery high-temperature or low-temperature performance, etc.

[0195] The positive electrode, separator, and negative electrode are stacked in sequence, with the separator acting as a separator between the positive and negative electrode to obtain an electrode assembly. Alternatively, the electrode assembly can be obtained by winding. Tabs are connected to the electrode assembly, and the electrode assembly is placed in a packaging shell. Excess water is removed by heating, followed by the injection of electrolyte and sealing. Finally, the secondary battery of this application is obtained through processes such as settling, hot and cold pressing, formation, shaping, and capacity testing.

[0196] Battery Module

[0197] This application provides a battery module that includes the secondary battery described in the above embodiments. Since it includes the secondary battery described in the above embodiments, this battery module also possesses the technical effects of the aforementioned secondary battery, which will not be elaborated upon here.

[0198] Battery pack

[0199] This application provides a battery pack, including the secondary battery or the battery module described in the above embodiments. Since it includes the secondary battery or battery module described in the above embodiments, the battery pack also possesses the technical effects of the aforementioned secondary battery or battery module, which will not be elaborated upon here.

[0200] Electrical appliances

[0201] This application provides an electrical device, including a secondary battery, a battery module, or a battery pack as described in the above embodiments. Because it includes the secondary battery, battery module, or battery pack described in the above embodiments, the electrical device has a longer service life and driving range.

[0202] The following detailed examples illustrate the dispersant, its preparation method, the slurry composition, and the secondary battery.

[0203] Example 1

[0204] Preparation of dispersants

[0205] The specific preparation steps of the dispersant are as follows:

[0206] (1) Dissolve 0.025 mol AIBN and 0.05 mol RAFT reagent in 300 mL of dioxane and stir for 1 h under a nitrogen atmosphere to obtain a mixed solution;

[0207] (2) 0.25 mol styrene and 0.25 mol ethylene were added to a mixed solution to carry out the first copolymerization reaction at a temperature of 60°C for 6 hours.

[0208] (3) After the first copolymerization reaction is completed, 0.25 mol of maleic anhydride and 0.25 mol of compound (R8 is ethylene oxide) with formula III) are subjected to a second copolymerization reaction, n=12, and the reaction is carried out for 6 hours;

[0209] (4) After the second copolymerization reaction is completed, the product is precipitated, filtered and dried to obtain a dispersant with the following structural formula.

[0210] Preparation of positive electrode sheet

[0211] The specific preparation steps for the positive electrode sheet are as follows:

[0212] (1) Carbon nanotubes, dispersant and part of N-methylpyrrolidone solvent (approximately 90% of the total weight of solvent) were mixed under stirring conditions to obtain a first mixture, wherein the stirring linear velocity was 3 m / s and the stirring time was 5 min;

[0213] (2) PVDF and the first mixture are stirred and mixed to obtain the second mixture, wherein the stirring linear velocity is 4 m / s and the stirring time is 5 min;

[0214] (3) Add lithium iron phosphate and the remaining N-methylpyrrolidone solvent to the second mixture and stir to obtain a positive electrode slurry, wherein the stirring linear speed is 5 m / s and the stirring time is 170 min;

[0215] (4) The positive electrode slurry is coated on the surface of aluminum foil, and after drying and cold pressing, a positive electrode sheet is obtained;

[0216] The weight ratio of lithium iron phosphate, carbon nanotubes, PVDF and dispersant is 91.9:5:3:0.1.

[0217] Preparation of negative electrode sheet

[0218] The specific preparation steps for the negative electrode sheet are as follows:

[0219] (1) Artificial graphite / silicon suboxide, Super P, and polyvinylidene fluoride (PVDF) are mixed thoroughly in a deionized water solvent system at a weight ratio of 96:2:2 to obtain a negative electrode slurry.

[0220] (2) The negative electrode slurry is coated onto copper foil, and after drying and cold pressing, a negative electrode sheet is obtained.

[0221] Preparation of electrolytes

[0222] In an argon atmosphere glove box (H2O < 0.1 ppm, O2 < 0.1 ppm), ethylene carbonate (EC) and ethyl methyl carbonate (EMC) are mixed uniformly at a volume ratio of 3:7 to obtain an organic solvent. Then, 12.5% ​​lithium hexafluorophosphate (LiPF6) is added and dissolved in the organic solvent and stirred evenly to obtain an electrolyte.

[0223] diaphragm

[0224] Polyethylene film is used as the diaphragm.

[0225] Preparation of secondary batteries

[0226] The positive electrode, separator, and negative electrode are stacked in sequence, with the separator acting as a separator between the positive and negative electrodes. Then, the electrode assembly is wound to obtain an electrode assembly, tabs are welded to the electrode assembly, and the electrode assembly is installed in an aluminum shell. The shell is then baked at 80°C to remove moisture, followed by the injection of the electrolyte and sealing. Finally, after processes such as settling, hot and cold pressing, formation, and shaping, the secondary battery of this embodiment is obtained.

[0227] Examples 2-26 and Comparative Example 1

[0228] The secondary batteries of Examples 2-26 and Comparative Example 1 were prepared in a similar manner to those of Example 1, with the differences listed in Table 1. In Example 17, the first repeating structural unit had the structure of formula (A), the second repeating structural unit had the structure of formula (B), and the fourth repeating structural unit had the structure of formula (C).

[0229] In Example 18, the first repeating structural unit has the structure of formula (D), the second repeating structural unit has the structure of formula (E), and the fourth repeating structural unit has the structure of formula (F).

[0230] In Example 19, the first repeating structural unit has the structure of formula (H), the second repeating structural unit has the structure of formula (M), and the fourth repeating structural unit has the structure of formula (G).

[0231] Testing of solid content in cathode slurry

[0232] The positive electrode slurry is coated onto aluminum foil and dried to obtain the positive electrode sheet. The formula for calculating the solid content W of the positive electrode slurry is as follows:

[0233] W = (m1 - m0) / (m2 - m0) × 100%

[0234] Where m0 is the mass of the aluminum foil, m1 is the mass of the dried positive electrode sheet, and m2 is the mass of the wet positive electrode sheet obtained after coating the aluminum foil with the positive electrode slurry.

[0235] Resistivity test of positive electrode

[0236] The resistivity of the diaphragm was directly tested using the Crystallography ST2263 dual-electrical-measurement digital four-probe tester.

[0237] Battery capacity retention test

[0238] In an environment of 25℃, the secondary battery was charged to 3.65V at a constant current of 1C, and then discharged to 2.5V at a constant current of 0.5C. The measured discharge capacity was recorded as the initial capacity C0. The above steps were repeated for the same battery, and the discharge capacity C of the battery after n cycles was recorded. n Battery capacity retention rate P after n cycles n =100% × C n / C0. The first cycle corresponds to n=1, the second cycle to n=2, and so on, up to the 100th cycle to n=100. The battery capacity retention rate was measured after 1000 cycles, and the test results are shown in Table 1.

[0239] Table 1

[0240] Note: T 总 This indicates the total stirring time for the formation of the positive electrode slurry composition, in minutes.

[0241] W represents the solid content in the slurry, expressed as a percentage.

[0242] Z represents the resistivity of the positive electrode, with units of Ω·cm;

[0243] K represents the capacity retention rate of the battery after 1000 cycles at 25°C, expressed as a percentage.

[0244] As shown in Table 1, the dispersant provided in this application embodiment can increase the solid content in the slurry, giving the slurry better stability. Furthermore, this slurry enables the electrode sheets to have lower resistance, and also gives the battery better capacity retention and cycle performance.

[0245] While this application has been described with reference to preferred embodiments, various modifications can be made thereto and components can be replaced with equivalents without departing from the scope of this application. In particular, the technical features mentioned in the various embodiments can be combined in any manner, provided there is no structural conflict. This application is not limited to the specific embodiments disclosed herein, but includes all embodiments falling within the scope of the claims.

Claims

1. A dispersant comprising a block copolymer having a first block and a second block; The first block includes a first repeating structural unit as shown in equation (I) and a second repeating structural unit as shown in equation (II): ， in, R1, R2, R3, R4, R5, R6 and R7 are each independently selected from hydrogen, halogen, cyano, carbonyl, carboxyl, nitro, sulfonic acid, amide, ester, substituted or unsubstituted C1-C15 alkyl, substituted or unsubstituted C1-C15 alkoxy, substituted or unsubstituted C6-C30 aryl. The second block includes a third repeating structural unit as shown in equation (III) and a fourth repeating structural unit as shown in equation (IV): ， Wherein, the average degree of polymerization n is any integer from 1 to 25, R8, R9, R 10 The dipole moment is greater than 2 10 -30 C·m; R8, R9, R 10 Each group is independently selected from hydroxyl, carboxyl, pyrrolidone, ethylene oxide, propylene oxide, halogen, substituted or unsubstituted C1-C15 alkyl, substituted or unsubstituted C1-C15 alkoxy, wherein R9 and R 10 They can be connected together as R9-OR 10 R9-NH-R 10 ; The weight-average molecular weight of the first block is in the range of 1,000-500,000, and the weight-average molecular weight of the second block is in the range of 1,000-500,000.

2. The dispersant according to claim 1, wherein, R1, R2, R3, R4, R5, R6 and R7 are each independently selected from hydrogen, halogen, cyano, substituted or unsubstituted C1-C12 alkyl, substituted or unsubstituted C6-C12 aryl.

3. The dispersant according to claim 2, wherein, R1, R2, R3, R4, R5, R6 and R7 are each independently selected from at least one of hydrogen, halogen, cyano, methyl, ethyl, propyl, butyl, pentyl, n-hexyl, phenyl and benzyl.

4. The dispersant according to claim 1 or 2, wherein, The first repeating structural unit has the following structural formula: ， The second repeating structural unit is ethylene.

5. The dispersant according to claim 1, wherein, The first block is a random copolymer block of the first repeating structural unit and the second repeating structural unit.

6. The dispersant according to claim 1, wherein, The average degree of polymerization ratio of the first block to the second block is (0.1-10):

1.

7. A method for preparing the dispersant according to any one of claims 1-6, comprising: The initiator and chain transfer agent were dissolved in an organic solvent and stirred under an inert atmosphere to obtain a mixed solution; A first copolymerization reaction is carried out by adding a monomer with a first block to the mixed solution; After the first copolymerization reaction is completed, the monomer of the second block is added to carry out the second copolymerization reaction; After the second copolymerization reaction is completed, the resulting product is precipitated, filtered, and dried to obtain the dispersant.

8. The preparation method according to claim 7, wherein, The stirring rate is in the range of 20 min / rpm to 1500 min / rpm.

9. The preparation method according to claim 8, wherein, The reaction temperature of the first copolymerization reaction is between -20℃ and 120℃.

10. A slurry composition for forming an electrode film, comprising the dispersant according to any one of claims 1-6, as well as a binder, an active material, and a conductive agent.

11. The slurry composition according to claim 10, wherein, The slurry composition comprises, by a total mass fraction of 100%, the following: Dispersant, 0.01%-10%; Adhesive, 0.5%-10%; Active materials, 82%-91.99%; Conductive agent, 0%-15%.

12. The slurry composition according to claim 10 or 11, wherein, The active material is a positive electrode active material.

13. A method for preparing a slurry composition as described in any one of claims 10-12, comprising: The conductive agent, dispersant, and a portion of the solvent are mixed under stirring conditions to obtain a first mixture; The adhesive is added to the first mixture and stirred to obtain the second mixture; The active material and the remaining solvent are added to the second mixture and stirred to obtain the slurry composition.

14. An electrode plate, comprising: current collector; An active material layer is disposed on at least one surface of the current collector, the active material layer being formed using the slurry composition described in any one of claims 10-12.

15. A secondary battery, wherein, include: Positive electrode sheet; Negative electrode sheet; A diaphragm is disposed between the positive electrode and the negative electrode; Wherein, the positive electrode and / or the negative electrode are the electrode plates as described in claim 14.

16. A battery module comprising the secondary battery as described in claim 15.

17. A battery pack comprising the secondary battery of claim 15 or the battery module of claim 16.

18. An electrical device comprising the secondary battery of claim 15, the battery module of claim 16, or the battery pack of claim 17.

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