Phosphorus-modified styrene-butadiene rubber polymer as well as preparation method and application thereof

Abstract

The invention provides a phosphorus-modified styrene-butadiene rubber polymer as well as a preparation method and application thereof. The structure of the polymer is # imgabs0 #. The method comprises the following steps: dissolving a styrene butadiene rubber polymer in a solvent to obtain a polymer glue solution; and adding a vinyl phosphonate monomer and an initiator into the glue solution, and carrying out a free radical grafting reaction to obtain a target product. The phosphorus-modified styrene-butadiene rubber polymer prepared by the preparation method disclosed by the invention is used for preparing an adhesive for a battery, and the adhesive has relatively good bonding performance, relatively good flame-retardant performance and electrolyte swelling resistance on a pole piece and a diaphragm, so that the safety performance of the battery can be improved, and the risks of battery bulging, fire and explosion are reduced.

Description

Technical Field

[0001] The invention belongs to the field of rubber modification, and in particular relates to a phosphorus-modified styrene-butadiene rubber polymer and a preparation method and application thereof. Background Art

[0002] Due to its long service life and high energy density, lithium-ion batteries are often used as power batteries for vehicles. However, safety accidents related to lithium-ion batteries have occurred frequently in recent years. The main reason is that the electrolyte used in traditional liquid lithium-ion batteries is an organic solvent. Most common electrolyte components are highly flammable substances, which can easily cause fires, spontaneous combustion, explosions and other accidents. Therefore, it is necessary to mix the electrolyte and positive and negative electrode materials with an adhesive that has flame retardant properties, good bonding properties, and resistance to electrolyte swelling to make safer battery core materials.

[0003] Patent CN1499658A discloses an explosion-proof diaphragm for lithium-ion secondary batteries. It adopts the method of adding flame retardant phosphate ester into the isolation membrane. However, the flame retardant itself cannot exist stably within the operating voltage range of the lithium battery, and the flame retardant effect after long-term charge and discharge cycles is not ideal.

[0004] Patent CN118336128A discloses a highly safe semi-solid lithium-ion battery and its preparation method. It uses a pre-polymerized acrylic acid ester to react with a phosphorus-containing flame retardant monomer to obtain a gel electrolyte membrane. However, the polymer body has poor swelling resistance to the electrolyte and is prone to structural damage and performance degradation when immersed in the electrolyte. Summary of the invention

[0005] To solve the above technical problems, the present invention aims to provide a phosphorus-modified styrene-butadiene rubber polymer and a preparation method thereof.

[0006] Another object of the present invention is to provide an application of the phosphorus-modified styrene-butadiene rubber polymer in the field of battery adhesives, which can improve the adhesive's bonding performance to electrodes and diaphragms, flame retardancy and resistance to electrolyte swelling, improve battery safety, and reduce the risk of battery swelling, fire, and explosion.

[0007] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0008] In a first aspect, the present invention provides a phosphorus-modified styrene-butadiene rubber polymer, wherein the polymer has a structure as shown in Formula 1 below:

[0009]

[0010] In the formula, R1 and R2 are independently selected from H, C1-12 alkyl, such as methyl, ethyl, propyl, butyl, etc.; R1 and R2 may be the same or different;

[0011] x is an integer ≥1, preferably x is an integer of 10 to 500; y is an integer ≥1, preferably y is an integer of 10 to 500; z is an integer ≥1, preferably z is an integer of 10 to 500; m is an integer ≥1, preferably m is an integer of 10 to 100; n is an integer ≥1, preferably n is an integer of 10 to 100.

[0012] The phosphorus-modified styrene-butadiene rubber polymer of the present invention has a number average molecular weight between 5w and 100w.

[0013] The phosphorus-modified styrene-butadiene rubber polymer of the present invention uses a reactive monomer containing phosphorus element, which is introduced into the polymer skeleton in the form of a covalent bond. This structure can better improve the flame retardant properties of the solid electrolyte, which cannot be ignited when encountering an open flame, and can improve the safety performance of the battery cell through the free radical quenching mechanism, effectively solving the problem of poor flame retardant performance of the battery. The polymer of the present invention also introduces ester groups, hydroxyl groups and the like, which can improve the bonding performance of the polymer to the electrode and the diaphragm.

[0014] In a second aspect, the present invention provides a method for preparing the phosphorus-modified styrene-butadiene rubber polymer represented by the aforementioned formula 1.

[0015] A method for preparing a phosphorus-modified styrene-butadiene rubber polymer, comprising the steps of:

[0016] S1: adding styrene-butadiene rubber polymer into solvent, heating and stirring to dissolve to obtain rubber solution;

[0017] S2: adding vinyl phosphate monomers and initiators to the rubber solution of step S1 to carry out free radical grafting reaction to obtain the phosphorus-modified styrene-butadiene rubber polymer.

[0018] In a specific embodiment, the styrene-butadiene rubber polymer in step S1 has the following

[0019] The structure shown in formula 2:

[0020]

[0021] In the formula, the values ​​of x, y, and z are the same as those in formula 1, that is, x is an integer ≥1, preferably x is an integer of 10 to 500; y is an integer ≥1, preferably y is an integer of 10 to 500; z is an integer ≥1, preferably z is an integer of 10 to 500;

[0022] As a preferred embodiment, the rubber polymer is one or more of solution-polymerized styrene-butadiene rubber, emulsion-polymerized styrene-butadiene rubber, and styrene-butadiene block copolymer.

[0023] In a specific embodiment, the solvent in step S1 is a solvent that has good solubility in both styrene-butadiene rubber and vinyl phosphate monomers, preferably one or more of N,N-dimethylformamide, N,N-dimethylacetamide, ethyl acetate, dimethyl sulfoxide, and N-methylpyrrolidone.

[0024] In a specific embodiment, the content of the styrene-butadiene rubber polymer in the rubber solution in step S1 is 5-30wt%, for example, 5wt%, 10wt%, 15wt%, 20wt%, 25wt%, 30wt%, etc.

[0025] In a specific embodiment, the dissolution in step S1 is carried out at a temperature of 80-100°C, for example, 80°C, 85°C, 90°C, 95°C, 100°C, etc., and the time is 2-8h, for example, 2h, 3h, 4h, 5h, 6h, 7h, 8h, etc.

[0026] In a specific embodiment, the vinyl phosphate monomer in step S2 has a structure as shown in Formula 3:

[0027]

[0028] In the formula, R1 and R2 are the same as in formula 1, that is, R1 and R2 are independently selected from H, C1-12 alkyl, etc.; R1 and R2 can be the same or different;

[0029] As a preferred embodiment, the vinyl phosphate monomer is a vinyl type monomer with a phosphonate group, preferably one or more of dibutyl vinyl phosphonate, dipropyl vinyl phosphonate, diethyl vinyl phosphonate, dimethyl vinyl phosphonate, vinyl phosphonic acid, more preferably vinyl phosphonic acid.

[0030] In a specific embodiment, the mass ratio of the vinyl phosphate monomer in step S2 to the styrene-butadiene rubber polymer in step S1 is (1-10):100, for example, 1:10, 1:20, 1:40, 1:60, 1:80, 1:100, etc.

[0031] In a specific embodiment, the initiator in step S2 is any initiator that can be used to initiate free radical polymerization and copolymerization of olefinic and diene monomers, including but not limited to one or more of azo initiators, peroxide initiators, anionic and cationic initiators;

[0032] Preferably, the initiator is selected from one or more of azobisisobutyronitrile, azobisisoheptanenitrile, azobisdimethylvaleronitrile, cumene hydroperoxide, tert-butyl hydroperoxide, p-menane hydroperoxide, potassium persulfate, ammonium persulfate, lauroyl peroxide, dibenzoyl peroxide, and dodecanoyl peroxide.

[0033] In a specific embodiment, the amount of the initiator in step S2 is 0.5-5% of the mass of the styrene-butadiene rubber polymer in step S1, for example, 0.5%, 1%, 2%, 3%, 4%, 5%, etc.

[0034] In a specific embodiment, the free radical grafting reaction in step S2 is carried out under an inert protective atmosphere, such as nitrogen, argon, helium, etc.

[0035] In a specific embodiment, the free radical grafting reaction in step S2 is carried out at a temperature of 80-100°C, such as 80°C, 85°C, 90°C, 95°C, 100°C, etc., and for a time of 2-6h, such as 2h, 3h, 4h, 5h, 6h, etc.

[0036] In a specific embodiment, the vinyl phosphate monomer and the initiator in step S2 are added dropwise for 1-4 hours, such as 1 hour, 2 hours, 3 hours, 4 hours, etc. The dropwise addition time is not included in the aforementioned reaction time. After the dropwise addition is completed, the reaction is kept warm.

[0037] In a third aspect, the present invention provides a use of the phosphorus-modified styrene-butadiene rubber polymer described above.

[0038] A use of a phosphorus-modified styrene-butadiene rubber polymer, wherein the polymer is the phosphorus-modified styrene-butadiene rubber polymer shown in the above formula 1, or the phosphorus-modified styrene-butadiene rubber polymer prepared by the above method, and the phosphorus-modified styrene-butadiene rubber polymer is used in the field of battery adhesives.

[0039] In a specific embodiment, the aforementioned phosphorus-modified styrene-butadiene rubber polymer is used as a raw material to prepare a battery core material having excellent flame retardant properties and good adhesion to the electrode sheet.

[0040] Specifically, the battery cell material with excellent flame retardant properties and good adhesion to the pole piece is prepared by the following method: A battery cell material with excellent flame retardant properties and good adhesion to the pole piece, including the phosphorus-modified styrene-butadiene rubber polymer and solvent (such as phosphonate-modified solution-polymerized styrene-butadiene rubber, N-methylpyrrolidone, vinyl phosphate and self-polymer), negative electrode battery materials such as graphite, conductive carbon black, carbon nanotubes, etc. This method is a known process in the field, and its related operations and process conditions, as well as the devices used, can all be carried out using conventional selections in the field. Technicians can optimize according to actual needs based on the known processes in the prior art, and the present invention has no special restrictions on this. Compared with the prior art, the positive effects of the present invention are:

[0041] 1) The formed polymer network can inhibit volume expansion during long-term immersion in the electrolyte, thereby improving the safety performance of the battery;

[0042] 2) By introducing reactive monomers containing phosphorus into the polymer skeleton in the form of covalent bonds and using them in battery cell materials, the flame retardant properties of the electrolyte can be better improved. It cannot be ignited when encountering an open flame. The safety performance of the battery cell can be improved through the free radical quenching mechanism, effectively solving problems such as poor flame retardant performance of the battery.

[0043] 3) The introduction of ester groups, hydroxyl groups and other groups improves the adhesion of the polymer to the electrode and the diaphragm. DETAILED DESCRIPTION

[0044] The present invention is further described below by means of specific examples. The examples described in the present invention are only used to illustrate the present invention and do not limit the scope of the present invention.

[0045] In the embodiments and comparative examples of the present invention, the sources of the main raw materials used are as follows. Unless otherwise specified, other raw materials and reagents were purchased from commercial sources:

[0046] Emulsion styrene butadiene rubber: ESBR 1500, Lee Chang Jung Chemical Co., Ltd.;

[0047] Solution styrene butadiene rubber: SSBR 2003, Shanghai Gaoqiao Petrochemical Co., Ltd.;

[0048] Styrene-butadiene block polymer: SBS1401 (YH-792E), Sinopec Baling Petrochemical Company;

[0049] N-Methylpyrrolidone: Shandong Changxin Chemical Technology Co., Ltd., purity >99%, CAS No. 872-50-4;

[0050] Ethyl acetate: Shanghai MacLean Biochemical Technology Co., Ltd., purity > 99%, CAS No. 141-78-6;

[0051] N,N-dimethylformamide: Shanghai MacLean Biochemical Technology Co., Ltd., purity> 99%, CAS No. 68-12-2;

[0052] Vinyl phosphonic acid: Shanghai MacLean Biochemical Technology Co., Ltd., purity > 97%, CAS No. 1746-03-8;

[0053] Diethyl vinylphosphonate: Haimen Ruiyi Pharmaceutical Technology Co., Ltd., purity> 97%, CAS No. 682-30-4;

[0054] Triethyl phosphonate: Shanghai MacLean Biochemical Technology Co., Ltd., purity > 99.8%, 78-40-0; Azobisisobutyronitrile: Zouping Mingxing Chemical Co., Ltd., purity > 99%, CAS No. 78-67-1;

[0055] Dibenzoyl peroxide: Shanghai MacLean Biochemical Technology Co., Ltd., purity > 75%, CAS No. 94-36-0;

[0056] Dodecyl peroxide: Shanghai MacLean Biochemical Technology Co., Ltd., purity> 75%, CAS No. 105-74-8.

[0057] The main performance analysis methods used in the embodiments of the present invention and the comparative examples are as follows:

[0058] Resistance to electrolyte swelling: Apply the slurry on the electrode, soak it in electrolyte for 14 days after curing, and then dry it at 120℃ to test the weight change;

[0059] Adhesion performance: Apply the slurry on the electrode, and after curing, measure the peel strength in N / m;

[0060] Capacity retention rate: Under the condition of 25±2℃, the battery cell is charged and discharged at 1C / 1C and the capacity retention rate of 50 cycles;

[0061] Heating: Charge the test cell at 1C to 100% SOC, then heat it from room temperature to 150°C at a heating rate of 5°C / min, keep it warm for 30 minutes, then continue to heat it at 5°C / min and keep it warm for 30 minutes every time the temperature rises by 5°C until thermal runaway occurs. The temperature of the previous stage of thermal runaway is the heating temperature.

[0062] Example 1

[0063] Take a 5000ml four-necked bottle, condense and reflux, and protect with nitrogen. Add 3000g N-methylpyrrolidone and 750g ESBR1500 into the reactor, stir and heat to 80℃ to dissolve the rubber for 2h to obtain a uniform rubber solution, add a mixed solution of 3.75g azobisisobutyronitrile and 7.5g diethyl vinylphosphonate dropwise, and the addition is completed within 3h. After the addition is completed, keep warm at 80℃ for 2h to obtain a phosphorus-modified styrene-butadiene rubber polymer with a number average molecular weight of 65402.

[0064] The phosphorus-modified styrene-butadiene rubber polymer prepared in this embodiment has the structural formula

[0065]

[0066] H 1NMR (300MHZ, DMSO-D6) δ1.25-1.3 (540H, m), 1.44-1.62 (712H, m), 1.77-1.8 (36H, m), 1.96-2.0 (1292H, m), 2.16-2 .18(186H,m), 4.18-4.19(72H,m), 5.02-5.07(360H,m), 5.42-5.48(652H,m), 5.7(180H,m), 7.27-7.37(1660H,m).

[0067] Example 2

[0068] Take a 5000ml four-necked bottle, condense and reflux, and protect with nitrogen. Add 3000g N,N-dimethylformamide and 1000g SBS1401 into the reactor, stir and heat to 100℃ to dissolve the rubber for 8h to obtain a uniform rubber solution, add a mixed solution of 25g dibenzoyl peroxide and 100g vinylphosphonic acid dropwise, and the addition is completed within 4h. After the addition is completed, keep warm at 100℃ for 2h to obtain a modified styrene-butadiene rubber polymer with a number average molecular weight of 100828.

[0069] The phosphorus-modified styrene-butadiene rubber polymer prepared in this embodiment has the structural formula

[0070]

[0071] H 1 NMR (300MHZ, DMSO-D6) δ1.25-1.3 (1026H, m), 1.44-1.62 (1263H, m), 1.77-1.8 (148H, m), 1.96-2.0 (1892H, m), 2.16 -2.18(199H,m), 5.02-5.07(250H,m), 5.42-5.48(1020H,m), 5.7(125H,m), 7.27-7.37(2060H,m), 11.98(342H,m).

[0072] Example 3

[0073] Take a 5000ml four-necked bottle, condense and reflux, and protect with nitrogen. Add 3000g ethyl acetate and 158g SSBR 2003 into the reactor, stir and heat to 90℃ to dissolve the rubber for 4h to obtain a uniform rubber solution, add a mixed solution of 7.9g dodecyl peroxide and 7.9g vinyl phosphoric acid dropwise, and the addition is completed within 1h. After the addition is completed, keep warm at 90℃ for 1h to obtain a modified styrene-butadiene rubber polymer with a number average molecular weight of 81016.

[0074] The phosphorus-modified styrene-butadiene rubber polymer prepared in this embodiment has the structural formula

[0075]

[0076] H 1 NMR (300MHZ, DMSO-D6) δ1.25-1.3 (640H, m), 1.44-1.62 (899H, m), 1.77-1.8 (44H, m), 1.96-2.0 (1908H, m), 2.16- 2.18(162H,m), 5.02-5.07(280H,m), 5.42-5.48(976H,m), 5.7(140H,m), 7.27-7.37(1800H,m), 11.98(134H,m).

[0077] Example 4

[0078] Take a 5000ml four-necked bottle, condense and reflux, and protect with nitrogen. Add 3000g N-methylpyrrolidone and 530g ESBR1500 into the reactor, stir and heat to 85℃ to dissolve the rubber for 6h to obtain a uniform rubber solution, add a mixed solution of 7.95g azobisisobutyronitrile and 10.6g vinyl dimethyl phosphate dropwise, and the addition is completed within 2h. After the addition is completed, keep warm at 85℃ for 2h to obtain a modified styrene-butadiene rubber polymer with a number average molecular weight of 68108.

[0079] The phosphorus-modified styrene-butadiene rubber polymer prepared in this embodiment has the structural formula

[0080]

[0081] H 1 NMR (300MHZ, DMSO-D6) δ1.25-1.3 (492H, m), 1.44-1.62 (769H, m), 1.77-1.8 (80H, m), 1.96-2.0 (1270H, m), 2.16 -2.18(186H,m), 3.66(240H,m), 5.02-5.07(342H,m), 5.42-5.48(650H,m), 5.7(171H,m), 7.27-7.37(1660H,m).

[0082] Example 5

[0083] Take a 5000ml four-necked bottle, condense and reflux, and protect with nitrogen. Add 3000g N-methylpyrrolidone and 1285g ESBR1500 into the reactor, stir and heat to 95℃ to dissolve the rubber for 7h to obtain a uniform rubber solution, add a mixed solution of 10.28g dibenzoyl peroxide and 38.55g vinyl dimethyl phosphate dropwise, and the addition is completed within 2.5h. After the addition is completed, keep warm at 95℃ for 2h to obtain a modified styrene-butadiene rubber polymer with a number average molecular weight of 69988.

[0084] The phosphorus-modified styrene-butadiene rubber polymer prepared in this embodiment has the structural formula

[0085]

[0086] H 1 NMR (300MHZ, DMSO-D6) δ1.25-1.3 (540H, m), 1.44-1.62 (809H, m), 1.77-1.8 (110H, m), 1.96-2.0 (1232H, m), 2.16 -2.18(185H,m), 3.66(330H,m), 5.02-5.07(330H,m), 5.42-5.48(636H,m), 5.7(165H,m), 7.27-7.37(1660H,m).

[0087] Application Example 1

[0088] The phosphorus-modified styrene-butadiene rubber polymer synthesized in the above Example 1 is used as one of the main ingredients of the battery core material, and the battery core material is prepared according to the following steps:

[0089] Graphite, silicon oxide, conductive carbon black, carbon nanotubes, phosphorus-modified styrene-butadiene rubber polymer and sodium carboxymethyl cellulose are mixed in a mass ratio of 84:12:1:0.5:1.5:1, and deionized water is added for homogenization. The mixture is evenly coated on the surface of copper foil on both sides, and then dried, rolled and die-cut to obtain a negative electrode sheet (sample A1).

[0090] The prepared sample A1 was tested for its tensile properties and swelling resistance, and was used in the battery to test battery cycle electrical performance tests and safety performance tests such as heating and acupuncture. The test results are shown in Table 1.

[0091] Application Example 2-5

[0092] Negative electrode sheets were prepared according to the method in Application Example 1, except that the phosphorus-modified styrene-butadiene rubber polymer was replaced by the products in Examples 2-5, respectively, to prepare negative electrode sheets, which were numbered A2-A5 in sequence. Performance tests were also conducted, and the results are shown in Table 1.

[0093] Comparative Example 1

[0094] Vinyl phosphonic acid diethyl ester was used as a raw material to prepare a vinyl phosphonic acid self-polymer, which was mixed with styrene butadiene rubber ESBR 1500 at the same mass ratio as that of ESBR 1500 and diethyl vinyl phosphonic acid in Example 1 to obtain a styrene butadiene rubber composition.

[0095] Comparative Example 2

[0096] Referring to the preparation method in Example 1, the only difference is that the raw material diethyl vinylphosphonate is replaced by triethyl phosphate, and other operations and conditions remain unchanged to obtain a modified styrene-butadiene rubber polymer.

[0097] Comparative application example 1

[0098] Negative electrode sheets D1 and D2 were prepared according to the method in Application Example 1, except that the phosphorus-modified styrene butadiene rubber polymer was replaced by the composition of styrene butadiene rubber and vinyl phosphoric acid self-polymer in Comparative Example 1 and the modified styrene butadiene rubber polymer prepared in Comparative Example 2. The performance test was also carried out, and the results are shown in Table 1.

[0099] Table 1 Performance test results

[0100]

[0101]

[0102] It can be seen from the data in Table 1 that the phosphorus-modified styrene-butadiene rubber polymer product prepared by the present invention can effectively enhance the resistance to electrolyte swelling, flame retardancy and bonding performance when used as a negative electrode adhesive for a battery, thereby improving the safety performance of the battery.

[0103] The above is only a preferred embodiment of the present invention. It should be pointed out that ordinary technicians in this field can make several improvements and supplements without departing from the method of the present invention. These improvements and supplements should also be regarded as the scope of protection of the present invention.

Claims

1. A phosphorus-modified styrene-butadiene rubber polymer, characterized in that: It has the structure shown in Formula 1: In the formula, R1 and R2 are independently selected from H, C1-12 alkyl, etc.; R1 and R2 may be the same or different; x is an integer ≥1, preferably x is an integer of 10 to 500; y is an integer ≥1, preferably y is an integer of 10 to 500; z is an integer ≥1, preferably z is an integer of 10 to 500; m is an integer ≥1, preferably m is an integer of 10 to 100; n is an integer ≥1, preferably n is an integer of 10 to 100.

2. The phosphorus-modified styrene-butadiene rubber polymer according to claim 1, characterized in that The number average molecular weight is 5w-100w.

3. A method for preparing the phosphorus-modified styrene-butadiene rubber polymer according to claim 1 or 2, characterized in that the steps include: S1: adding styrene-butadiene rubber polymer into solvent, heating and stirring to dissolve to obtain rubber solution; S2: adding vinyl phosphate monomers and initiators to the rubber solution of step S1 to carry out free radical grafting reaction to obtain the phosphorus-modified styrene-butadiene rubber polymer.

4. The preparation method according to claim 3, characterized in that: The styrene-butadiene rubber polymer in step S1 has a structure as shown in Formula 2: In the formula, the values ​​of x, y, and z are the same as those in formula 1; Preferably, the rubber polymer is one or more of solution polymerized styrene butadiene rubber, emulsion polymerized styrene butadiene rubber, and styrene-butadiene block copolymer.

5. The preparation method according to claim 3, characterized in that: The solvent in step S1 is one or more of N,N-dimethylformamide, N,N-dimethylacetamide, ethyl acetate, dimethyl sulfoxide, and N-methylpyrrolidone; and / or In step S1, the content of the styrene-butadiene rubber polymer in the rubber solution is 5-30wt%.

6. The preparation method according to claim 3, characterized in that: The dissolution in step S1 is performed at a temperature of 80-100° C. for 2-8 hours.

7. The preparation method according to claim 3, characterized in that: The vinyl phosphate monomer in step S2 has a structure as shown in Formula 3: Wherein, R1 and R2 are the same as those in Formula 1; Preferably, the vinyl phosphate monomer is a vinyl monomer with a phosphonate group, preferably one or more of dibutyl vinyl phosphonate, dipropyl vinyl phosphonate, diethyl vinyl phosphonate, dimethyl vinyl phosphonate, vinyl phosphonic acid, more preferably vinyl phosphonic acid; and / or The mass ratio of the vinyl phosphate monomer in step S2 to the styrene-butadiene rubber polymer in step S1 is (1-10):

100.

8. The preparation method according to claim 3, characterized in that: The initiator in step S2 is one or more of an azo initiator, a peroxide initiator, an anionic and cationic initiator; Preferably, the initiator is selected from one or more of azobisisobutyronitrile, azobisisoheptanenitrile, azobisdimethylvaleronitrile, cumene hydroperoxide, tert-butyl hydroperoxide, p-menane hydroperoxide, potassium persulfate, ammonium persulfate, lauroyl peroxide, dibenzoyl peroxide, and dodecanoyl peroxide; and / or The amount of the initiator used in step S2 is 0.5-5% of the mass of the styrene-butadiene rubber polymer in step S1.

9. The preparation method according to claim 3, characterized in that: The free radical grafting reaction in step S2 is carried out under an inert protective atmosphere, such as nitrogen, argon, or helium; and / or The free radical grafting reaction in step S2 is carried out at a temperature of 80-100° C. for 2-6 hours; and / or In step S2, the vinyl phosphate monomer and the initiator are added dropwise for 1-4 hours. The dropwise addition time is not included in the above-mentioned reaction time. After the dropwise addition is completed, the reaction is kept warm.

10. Use of the phosphorus-modified styrene-butadiene rubber polymer according to claim 1 or 2, or the phosphorus-modified styrene-butadiene rubber polymer prepared by the method according to any one of claims 3 to 9 in the field of battery adhesives.

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