Lithium battery positive electrode slurry binder using hydrogenated nitrile rubber, preparation method of lithium battery positive electrode slurry binder and lithium battery positive electrode plate

Abstract

The invention relates to the technical field of lithium battery materials, in particular to a lithium battery positive electrode slurry binder using hydrogenated butadiene-acrylonitrile rubber, a preparation method of the lithium battery positive electrode slurry binder and a lithium battery positive electrode plate. The lithium battery positive electrode slurry binder using hydrogenated nitrile rubber comprises the following preparation raw materials in parts by mass: 5-25 parts of hydrogenated nitrile rubber, 75-90 parts of N-methyl pyrrolidone and cosolvent, and 0.1-5 parts of stabilizer. Through a specific ratio and a preparation process, the problem of poor solubility of high-hydrogenation-degree HNBR in a conventional solvent is solved, and the room-temperature stability, uniformity and operability of the slurry are enhanced. The coating applicability of the slurry is optimized, and the risk of environmental pollution is reduced.

Description

Technical Field

[0001] The present application relates to the technical field of lithium battery materials, and in particular to a lithium battery positive electrode slurry binder using hydrogenated nitrile rubber, a preparation method thereof, and a lithium battery positive electrode sheet. Background Art

[0002] Lithium-ion battery is a secondary battery that relies on the movement of lithium ions between the positive electrode and the negative electrode to work. The positive electrode material of lithium battery is part of the material constituting the lithium-ion battery, which directly affects the performance of the lithium-ion battery and occupies a large proportion (the mass ratio of positive and negative electrode materials is 3:1-4:1). Usually, the positive electrode material needs to be prepared into a mixture containing active substances (such as LiCoO2, LiFePO4, etc.), dispersants, binders, conductive agents (such as carbon black) and solvents. After stirring, kneading and dispersion, it is coated on the current collector (such as aluminum foil) to form a positive electrode sheet.

[0003] In the manufacturing process of lithium-ion batteries, PVDF is widely used as a binder. PVDF contains fluorine elements, which has certain environmental pollution risks, and has weak elasticity. It will undergo irreversible deformation when the elongation is only 10%; HNBR has greater adhesion than PVDF in lithium iron phosphate battery and lithium titanate battery systems. In addition, the electrochemical stability is also better than PVDF. Hydrogenated nitrile rubber (HNBR), as a rubber material with excellent heat resistance and chemical stability, has great application potential in replacing PVDF as a binder. However, in order to ensure that HNBR has good stability in the positive electrode slurry of lithium batteries, the hydrogenation degree of HNBR is usually required to be greater than 99%. However, HNBR with a high degree of hydrogenation has poor solubility in N-methylpyrrolidone (NMP), the most common organic solvent used in the positive electrode slurry of lithium batteries, because it forms polyethylene segments. Even in good solvents such as toluene and xylene, it requires a higher temperature and is difficult to dissolve at room temperature, which limits its application as a binder. Chinese patent CN115842095A improves the solubility of HNBR by adding active groups, including carboxyl, amine, hydroxyl, and epoxy groups. Chinese patent CN116314789A realizes the application of HNBR in lithium battery positive electrode slurry by forming a ternary mixture and adding a compatibilizer. However, the above patents all require high costs and affect the performance of HNBR. Therefore, ensuring the applicability of HNBR to lithium battery positive electrode slurry is of great significance in the optimization and improvement of lithium batteries. Summary of the invention

[0004] In view of the shortcomings of the prior art, the present application provides a lithium battery positive electrode slurry binder using hydrogenated nitrile rubber, a preparation method thereof, and a lithium battery positive electrode sheet. The present application effectively improves the room temperature stability and coating applicability of the lithium battery positive electrode slurry binder through a specific ratio and preparation process. The binder of the present application shows excellent uniformity and stability in the preparation of lithium battery positive electrode sheets, significantly improving the overall performance of lithium batteries.

[0005] In the first aspect, the present application provides a lithium battery positive electrode slurry binder using hydrogenated nitrile rubber, using the following technical solution: A lithium battery positive electrode slurry binder using hydrogenated nitrile rubber comprises the following preparation raw materials by weight: 5-25 parts of hydrogenated nitrile rubber, 75-90 parts of N-methylpyrrolidone and co-solvent, and 0.1-5 parts of stabilizer.

[0006] By adopting the above technical scheme, hydrogenated nitrile rubber (HNBR): as the main material of the binder of the positive electrode slurry of lithium batteries, it provides the necessary bonding performance. Through specific hydrogenation treatment, HNBR can improve its compatibility with the positive electrode material of lithium batteries. At the same time, the hydrogenation treatment of HNBR also helps to improve its solubility and stability at room temperature. N-methylpyrrolidone (NMP): as the main solvent, NMP can effectively dissolve HNBR and improve its solubility at room temperature. At the same time, the low volatility of NMP also helps to maintain the stability of the slurry. Co-solvents: including decahydronaphthalene, tetrahydronaphthalene, carbon disulfide and cyclohexane. These co-solvents work together with NMP to further improve the solubility of HNBR, and also help to improve the rheological properties and coating applicability of the slurry. Stabilizer: low-temperature hydrogenated nitrile rubber with acrylic copolymer units, the main function of which is to improve the stability of the binder at room temperature and prevent solution stratification or gelation. At the same time, the stabilizer also helps to maintain the uniformity and operability of the slurry. The combined effect of NMP and co-solvent significantly improves the solubility of HNBR at room temperature, solving the problem of poor solubility of HNBR with high degree of hydrogenation in conventional solvents. The addition of stabilizer improves the stability of the binder at room temperature, avoids solution stratification or gelation, and ensures the uniformity and operability of the slurry. The synergistic effect of co-solvent and stabilizer improves the rheological properties of the binder, making it easier to coat, and improves the uniformity and adhesion of the positive electrode slurry on the current collector. The use of HNBR instead of traditional PVDF as a binder reduces the use of fluorine elements, reduces the risk of environmental pollution, and meets the requirements of green manufacturing and sustainable development. In summary, these components work synergistically through specific ratios and preparation processes to jointly improve the performance of the lithium battery positive electrode slurry binder, including solubility, room temperature stability, coating applicability and environmental protection.

[0007] Preferably, the hydrogenated nitrile rubber has an acrylonitrile content of 33-50%, a number average molecular weight of 20,000 to 2,000,000, and a degree of hydrogenation greater than 95%.

[0008] Preferably, the co-solvent is at least one of decahydronaphthalene, tetrahydronaphthalene, carbon disulfide and cyclohexane; and the mass ratio of the co-solvent to N-methylpyrrolidone is 1:3 to 3:1.

[0009] By adopting the above technical scheme, decahydronaphthalene has good solubility and stability. It can effectively dissolve hydrogenated nitrile rubber while maintaining the stability of the solution. Tetrahydronaphthalene has good solubility and stability. It can form a co-solvent system with N-methylpyrrolidone to improve the solubility of the binder. Carbon disulfide has strong dissolving ability. It can be mixed with other solvents under specific conditions to improve the dissolution efficiency. Cyclohexane has good solubility and stability. It can be mixed with other solvents to improve the solubility and stability of the binder. The mass fraction ratio of the co-solvent to N-methylpyrrolidone is 1:3 to 3:1. The adjustment of this ratio is adjusted according to specific needs and experimental results to achieve the best solubility and stability effect. The co-solvent system formed by the co-solvent and N-methylpyrrolidone can significantly improve the solubility of hydrogenated nitrile rubber at room temperature. This is because the co-solvent can interact with N-methylpyrrolidone to form a stable solution system, thereby improving the dissolution efficiency. The presence of the co-solvent helps to improve the stability of the binder at room temperature and avoid solution stratification or gelation. This is because the co-solvent can interact with N-methylpyrrolidone to form a stable solution system. The synergistic effect of the co-solvent and the stabilizer can improve the rheological properties of the binder, making it easier to coat. This is because the co-solvent can improve the fluidity of the binder, while the stabilizer can maintain the stability of the solution. In summary, the selection and ratio of co-solvents are crucial to improving the performance of the binder for lithium battery positive electrode slurry. By reasonably selecting and adjusting the type and ratio of co-solvents, the solubility, stability and coating applicability of the binder can be effectively improved, thereby improving the overall performance of the lithium battery.

[0010] Preferably, the stabilizer is a low-temperature hydrogenated nitrile rubber having an acrylic acid copolymer unit, wherein the acrylonitrile content is 21-25%; the number average molecular weight of the low-temperature hydrogenated nitrile rubber having an acrylic acid copolymer unit is 2,000 to 20,000.

[0011] In a second aspect, the present application provides a method for preparing a lithium battery positive electrode slurry binder using hydrogenated nitrile rubber, using the following technical solution: As a general technical concept, the present application also provides a method for preparing the above-mentioned lithium battery positive electrode slurry binder using hydrogenated nitrile rubber, comprising the following steps: S61, mixing N-methylpyrrolidone and a co-solvent in proportion by mass, stirring evenly to form a co-solvent system; S62, adding a stabilizer to the co-solvent system according to the mass fraction, heating and stirring to dissolve it, and obtaining a mixed solution; S63. Add hydrogenated nitrile rubber to the mixed solution according to the mass fraction, continue heating and stirring to dissolve, and then cool to room temperature to obtain a lithium battery positive electrode slurry binder using hydrogenated nitrile rubber.

[0012] Preferably, in step S62, the heating temperature is 80-85°C.

[0013] Preferably, in step S63, the temperature of the stirring and dissolving is 80-160°C, and the stirring time is at least 6 hours.

[0014] In a third aspect, the present application provides a lithium battery positive electrode sheet using a lithium battery positive electrode slurry binder of hydrogenated nitrile rubber, which adopts the following technical solution: As a general technical concept, the present application also provides a lithium battery positive electrode sheet, comprising mixing a positive electrode active material, a conductive agent, a dispersant and the above-mentioned lithium battery positive electrode slurry binder using hydrogenated nitrile rubber, mixing by high-speed stirring and homogenization process to form a uniform positive electrode slurry, and then uniformly coating the slurry on a current collector, and after drying, obtaining a lithium battery positive electrode sheet.

[0015] Preferably, the mass ratio of the positive electrode active material, the conductive agent, the dispersant and the lithium battery positive electrode slurry binder using hydrogenated nitrile rubber is 90-95:2-3:1-1.5:2-3.

[0016] Preferably, 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 base and a metal layer formed on at least one surface of the polymer material base. 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.). The positive electrode active material may be a positive electrode active material for a battery known in the art. As an example, the positive electrode active material may include at least one of the following materials: a lithium-containing phosphate with an olivine structure, a lithium transition metal oxide and their respective modified compounds. However, the present application is not limited to these materials, and other traditional materials that can be used as positive electrode active materials for batteries may also be used. These positive electrode active materials may be used alone or in combination of two or more. Among them, examples of lithium transition metal oxides may include but are not limited to at least one 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 modified compounds thereof. Examples of lithium phosphates containing olivine structures may include but are not limited to at least one of lithium iron phosphate, lithium manganese phosphate, a composite material of lithium manganese phosphate and carbon, lithium iron manganese phosphate, and a composite material of lithium iron manganese phosphate and carbon. The conductive agent may include at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene and carbon nanofibers. The dispersant includes polyvinyl pyrrolidone and hexadecyl trimethylammonium bromide.

[0017] In summary, the present application includes at least one of the following beneficial technical effects: 1. Improve solubility: By introducing a co-solvent system combined with N-methylpyrrolidone (NMP), the solubility of hydrogenated nitrile rubber (HNBR) at room temperature is significantly improved. This improvement solves the problem of poor solubility of highly hydrogenated HNBR in conventional solvents, thereby ensuring the uniformity and stability of lithium battery positive electrode slurry.

[0018] 2. Enhance room temperature stability: Adding low-temperature hydrogenated nitrile rubber with acrylic acid copolymer units as a stabilizer effectively improves the stability of hydrogenated nitrile rubber binder at room temperature. This improvement avoids solution stratification or gelation, ensuring the uniformity and operability of the slurry.

[0019] 3. Optimize coating applicability: The synergistic effect of co-solvent and stabilizer improves the rheological properties of hydrogenated nitrile rubber binder, making it easier to coat. This improvement improves the uniformity and adhesion of the positive electrode slurry on the current collector (such as aluminum foil), thereby improving the overall performance of the lithium battery.

[0020] 4. Improved environmental protection: Hydrogenated nitrile rubber is used to replace traditional PVDF as a binder, reducing the use of fluorine. This improvement reduces the risk of environmental pollution and meets the requirements of green manufacturing and sustainable development. At the same time, it also helps to reduce dependence on resources and reduce costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following is a brief introduction to the drawings used in the embodiments: Figure 1 This is the dissolution curve of hydrogenated nitrile rubber in solvents composed of different proportions of NMP and carbon disulfide. DETAILED DESCRIPTION

[0022] The embodiments of the present application will be described in detail below in conjunction with the examples, but it will be appreciated by those skilled in the art that the following examples are only used to illustrate the present application and should not be considered as limiting the scope of the present application. In the examples, if specific conditions are not specified, they are carried out according to normal conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0023] In the above embodiments, the hydrogenated nitrile rubber has an acrylonitrile content of 40%, a number average molecular weight of 500,000, and a hydrogenation degree of 96%; the stabilizer is a low-temperature hydrogenated nitrile rubber having an acrylic acid copolymer unit, wherein the acrylonitrile content is 23%; and its number average molecular weight is 16,000. In the embodiments, 1 part means 100 g.

[0024] Example 1 A lithium battery positive electrode slurry binder using hydrogenated nitrile rubber, comprising the following raw materials by weight: 10 parts of hydrogenated nitrile rubber, 85 parts of N-methylpyrrolidone and carbon disulfide, and 2 parts of a stabilizer, wherein the mass ratio of carbon disulfide to N-methylpyrrolidone is 1:3; The above-mentioned method for preparing a lithium battery positive electrode slurry binder using hydrogenated nitrile rubber comprises the following steps: S61, mixing N-methylpyrrolidone and carbon disulfide in a mass ratio, stirring evenly to form a co-solvent system; S62. Add the stabilizer to the co-solvent system according to the mass fraction, heat it to 80°C, stir it to dissolve it, and obtain a mixed solution; S63. Add the hydrogenated nitrile rubber to the mixed solution according to the mass fraction, continue heating it to 90°C, stir it for 8 hours until it is completely dissolved, and then cool it to room temperature to obtain a lithium battery positive electrode slurry binder using hydrogenated nitrile rubber.

[0025] Example 2 A lithium battery positive electrode slurry binder using hydrogenated nitrile rubber, comprising the following raw materials by weight: 15 parts of hydrogenated nitrile rubber, 80 parts of N-methylpyrrolidone and decalin, and 3 parts of a stabilizer, wherein the weight ratio of decalin to N-methylpyrrolidone is 1:1; The above-mentioned method for preparing a lithium battery positive electrode slurry binder using hydrogenated nitrile rubber comprises the following steps: S61, mixing N-methylpyrrolidone and decalin in a mass ratio, stirring evenly to form a co-solvent system; S62. Add the stabilizer to the co-solvent system according to the mass fraction, heat it to 85°C, stir it to dissolve it, and obtain a mixed solution; S63. Add the hydrogenated nitrile rubber to the mixed solution according to the mass fraction, continue heating it to 90°C, stir it for 7 hours until it is completely dissolved, and then cool it to room temperature to obtain a lithium battery positive electrode slurry binder using hydrogenated nitrile rubber.

[0026] Example 3 A lithium battery positive electrode slurry binder using hydrogenated nitrile rubber comprises the following raw materials by weight: 20 parts of hydrogenated nitrile rubber, 75 parts of N-methylpyrrolidone and cyclohexane, and 4 parts of a stabilizer, wherein the weight ratio of cyclohexane to N-methylpyrrolidone is 1:3.

[0027] The above-mentioned method for preparing a lithium battery positive electrode slurry binder using hydrogenated nitrile rubber comprises the following steps: S61, mixing N-methylpyrrolidone and cyclohexane in a mass ratio, stirring evenly to form a co-solvent system; S62. Add the stabilizer to the co-solvent system according to the mass fraction, heat it to 82°C, stir it to dissolve it, and obtain a mixed solution; S63. Add the hydrogenated nitrile rubber to the mixed solution according to the mass fraction, continue heating it to 100°C, stir it for 6 hours until it is completely dissolved, and then cool it to room temperature to obtain a lithium battery positive electrode slurry binder using hydrogenated nitrile rubber.

[0028] Example 4 A lithium battery positive electrode slurry binder using hydrogenated nitrile rubber comprises the following raw materials by weight: 25 parts of hydrogenated nitrile rubber, 90 parts of N-methylpyrrolidone and tetralin, and 4 parts of a stabilizer, wherein the mass ratio of tetralin to N-methylpyrrolidone is 3:1.

[0029] The above-mentioned method for preparing a lithium battery positive electrode slurry binder using hydrogenated nitrile rubber comprises the following steps: S61, mixing N-methylpyrrolidone and tetralin in a mass ratio, stirring evenly to form a co-solvent system; S62. Add the stabilizer to the co-solvent system according to the mass fraction, heat it to 83°C, stir it to dissolve it, and obtain a mixed solution; S63. Add the hydrogenated nitrile rubber to the mixed solution according to the mass fraction, continue heating it to 120°C, stir it for 7 hours until it is completely dissolved, and then cool it to room temperature to obtain a lithium battery positive electrode slurry binder using hydrogenated nitrile rubber.

[0030] Application Example 1 A lithium battery positive electrode sheet is prepared by mixing a positive electrode active material LiFePO4, a conductive agent carbon black (Super P), polyvinyl pyrrolidone, and a lithium battery positive electrode slurry binder using hydrogenated nitrile rubber prepared in Example 1 in a proper amount of NMP at a mass ratio of 94:3:1.5:2.5, mixing by high-speed stirring and homogenizing process to form a uniform positive electrode slurry, and then evenly coating the slurry on an aluminum foil, and drying to obtain a lithium battery positive electrode sheet.

[0031] Application Example 2 A lithium battery positive electrode sheet is prepared by mixing a positive electrode active material LiFePO4, a conductive agent carbon black (Super P), polyvinyl pyrrolidone, and a lithium battery positive electrode slurry binder using hydrogenated nitrile rubber prepared in Example 2 in a mass ratio of 94:3:1.5:2.5 in an appropriate amount of NMP, mixing by high-speed stirring and homogenizing to form a uniform positive electrode slurry, and then evenly coating the slurry on an aluminum foil. After drying, a lithium battery positive electrode sheet is obtained.

[0032] Application Example 3 A lithium battery positive electrode sheet is prepared by mixing a positive electrode active material LiFePO4, a conductive agent carbon black (Super P), polyvinyl pyrrolidone, and a lithium battery positive electrode slurry binder using hydrogenated nitrile rubber prepared in Example 3 in a mass ratio of 94:3:1.5:2.5 in an appropriate amount of NMP, mixing by high-speed stirring and homogenizing process to form a uniform positive electrode slurry, and then evenly coating the slurry on an aluminum foil, and drying to obtain a lithium battery positive electrode sheet.

[0033] Application Example 4 A lithium battery positive electrode sheet is prepared by mixing a positive electrode active material LiFePO4, a conductive agent carbon black (Super P), polyvinyl pyrrolidone, and a lithium battery positive electrode slurry binder using hydrogenated nitrile rubber prepared in Example 4 in a mass ratio of 94:3:1.5:2.5 in an appropriate amount of NMP, mixing by high-speed stirring and homogenizing process to form a uniform positive electrode slurry, and then evenly coating the slurry on an aluminum foil, and drying to obtain a lithium battery positive electrode sheet.

[0034] 1. Dissolution test of hydrogenated nitrile rubber in solvents composed of NMP and carbon disulfide in different proportions. Dissolve 100g of hydrogenated nitrile rubber in 850g of solutions composed of N-methylpyrrolidone and carbon disulfide in different proportions, heat, and test the temperature at which it is completely dissolved. In the solutions composed of N-methylpyrrolidone and carbon disulfide in different proportions, the mass ratio of carbon disulfide is 0, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100%. The test results are as follows: Figure 1 As shown. Figure 1 It can be seen that when the mass ratio of carbon disulfide is between 20-40%, hydrogenated nitrile rubber can be completely dissolved at room temperature of 10-20°C.

[0035] 2. Performance test Adhesion test: Cut the prepared positive electrode sheet into test samples of 20mm×100mm size for later use; stick one side of the double-sided tape to the surface of the steel plate, and stick the other side to the electrode to be tested, and compact it with a roller to make it completely fit with the electrode; bend one end of the current collector in the opposite direction, with a bending angle of 180°; use a high-speed rail tensile machine to test, fix one end of the steel plate to the lower fixture of the tensile machine, and fix the bent end of the current collector to the upper fixture, adjust the angle of the current collector to ensure that the upper and lower ends are in a vertical position, and then stretch the sample at a speed of 50mm / min until the current collector is completely peeled off from the surface of the electrode, record the displacement and force in the process, and take the force when the force is balanced as the adhesion of the electrode. The results are shown in Table 1.

[0036] Solution stability refers to the ability of a solution to maintain its original chemical and physical properties within a certain period of time without precipitation, precipitation, discoloration, or deterioration. The stability of the solution was determined by observing the solution under a microscope to see if there was precipitation, turbidity, or discoloration, and the solution was evaluated as excellent, good, fair, or poor. The results are shown in Table 1.

[0037] Coating suitability: Use a coating machine to coat, observe the coating effect, evaluate the performance of the slurry in actual coating, such as uniformity and adhesion, and evaluate it with excellent, good, medium, and poor. The results are shown in Table 1.

[0038] Table 1 Performance test Analyzing the data in Table 1, we can see that: The application of the lithium battery positive electrode slurry binder using hydrogenated nitrile rubber prepared in Example 1 in the preparation of lithium battery positive electrode sheets has the best performance in terms of room temperature stability and coating applicability, and is suitable for the preparation of lithium battery positive electrode sheets with high requirements. The application of the lithium battery positive electrode slurry binder using hydrogenated nitrile rubber prepared in Examples 2 to 4 in the preparation of lithium battery positive electrode sheets, although slightly inferior in some aspects, can still meet the needs of general lithium battery production.

[0039] The above embodiments are only used to explain the technical solutions of the present application rather than to limit them. Although the above embodiments provide a specific description of the present application, relevant technical personnel should understand that the specific implementation methods of the present application can still be modified or replaced by equivalents, and any modifications and equivalent replacements that do not depart from the spirit and scope of the present application should be included in the protection scope of the present application.

Claims

1. A lithium battery positive electrode slurry binder using hydrogenated nitrile rubber, characterized in that: The preparation raw materials include the following by weight: 5-25 parts of hydrogenated nitrile rubber, 75-90 parts of N-methylpyrrolidone and co-solvent, and 0.1-5 parts of stabilizer.

2. A lithium battery positive electrode slurry binder using hydrogenated nitrile rubber according to claim 1, characterized in that: The hydrogenated nitrile rubber has an acrylonitrile content of 33-50%, a number average molecular weight of 20,000 to 2,000,000, and a hydrogenation degree of more than 95%.

3. The lithium battery positive electrode slurry binder using hydrogenated nitrile rubber according to claim 1, characterized in that: The co-solvent is at least one of decahydronaphthalene, tetrahydronaphthalene, carbon disulfide and cyclohexane.

4. The lithium battery positive electrode slurry binder using hydrogenated nitrile rubber according to claim 1, characterized in that: The mass ratio of the co-solvent to N-methylpyrrolidone is 1:3 to 3:

1.

5. The lithium battery positive electrode slurry binder using hydrogenated nitrile rubber according to claim 1, characterized in that: The stabilizer is a low-temperature hydrogenated nitrile rubber having an acrylic acid copolymer unit, wherein the acrylonitrile content is 21-25%; the number average molecular weight of the low-temperature hydrogenated nitrile rubber having an acrylic acid copolymer unit is 2,000 to 20,000.

6. A method for preparing a lithium battery positive electrode slurry binder using hydrogenated nitrile rubber as claimed in any one of claims 1 to 5, characterized in that: The following steps are involved: S61, mixing N-methylpyrrolidone and a co-solvent in proportion by mass, stirring evenly to form a co-solvent system; S62, adding a stabilizer to the co-solvent system according to the mass fraction, heating and stirring to dissolve it, and obtaining a mixed solution; S63. Add hydrogenated nitrile rubber to the mixed solution according to the mass fraction, continue heating and stirring to dissolve, and then cool to room temperature to obtain a lithium battery positive electrode slurry binder using hydrogenated nitrile rubber.

7. The method for preparing a lithium battery positive electrode slurry binder using hydrogenated nitrile rubber according to claim 6, characterized in that: In step S62, the heating temperature is 80-85°C.

8. The method for preparing a lithium battery positive electrode slurry binder using hydrogenated nitrile rubber according to claim 6, characterized in that: In step S63, the temperature of the stirring and dissolving is 80-160°C, and the stirring time is at least 6 hours.

9. A lithium battery positive electrode plate, characterized in that: The method comprises mixing a positive electrode active material, a conductive agent, a dispersant and a lithium battery positive electrode slurry binder using hydrogenated nitrile rubber as described in any one of claims 1 to 5, mixing by high-speed stirring and homogenizing process to form a uniform positive electrode slurry, and then uniformly coating the slurry on a current collector, and obtaining a lithium battery positive electrode sheet after drying.

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