Preparation method of water-based primer for lithium battery foil

Abstract

The invention provides a preparation method of a water-based primer for a lithium battery foil, and relates to the technical field of lithium ion batteries. And adding the composite conductive material, the modified water-based acrylic resin and the dispersing agent into the first solvent, and stirring and mixing for 4-6 hours at the rotating speed of 800-1200 r / min in an environment of 35-45 DEG C to obtain the water-based primer. According to the preparation method provided by the invention, the target of forming the efficient coating on the surface of the lithium battery foil is achieved through an ingenious formula design. The composite conductive material and the modified water-based acrylic resin jointly act on the surface of the foil material to form a conductive network, so that the contact resistance between the active material and the foil material is effectively reduced, the overall conductivity of the foil material is also remarkably improved, and a powerful guarantee is provided for efficient operation of the lithium battery.

Description

Technical Field

[0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to a method for preparing an aqueous primer for lithium battery foil. Background Art

[0002] Aluminum foil plays a key role as the positive electrode current collector in lithium batteries. It not only carries active materials, but also is responsible for collecting the electrons generated by the active materials to the external circuit to form current. Therefore, the electrochemical behavior of aluminum foil has a direct impact on battery performance. Traditionally, the surface of aluminum foil is modified by acid and alkali corrosion to reduce its surface tension, but this method is difficult to control precisely and it is difficult to obtain a uniform surface morphology.

[0003] In contrast, using a functional coating to surface treat the positive electrode current collector of the battery is a more effective method. By uniformly coating a layer of conductive material on the surface of the aluminum foil, it is not only possible to improve the liquid absorption capacity of the positive electrode and enhance the adhesion between the active material and the current collector, but also to improve the ability of the positive electrode to collect microcurrents of the active material, reduce contact resistance, and reduce polarization, thereby improving the consistency and rate performance of the battery. In addition, the functional coating can also protect the aluminum foil and slow down corrosion. However, the existing functional coatings have the problem of being easily corroded by the electrolyte, and the heat generated when the battery is working may cause the aluminum foil to oxidize, causing the attached materials to fall off, affecting the normal operation of the lithium battery, and even posing a safety hazard. At the same time, in order to make the active material firmly adhere to the smooth surface of the metal current collector, it is usually necessary to add more insulating binders, which will reduce the conductivity and energy density of the electrode.

[0004] Therefore, providing a water-based primer for lithium battery foil with good conductive properties is an important issue to be solved in the art. Summary of the invention

[0005] In order to solve the deficiencies of the prior art, the present invention provides a method for preparing a water-based primer for lithium battery foil. To achieve the above object, the present invention adopts the following technical scheme:

[0006] A method for preparing an aqueous primer for lithium battery foil, the method comprising the following steps:

[0007] The composite conductive material, modified water-based acrylic resin and dispersant are added to the first solvent, and stirred and mixed at a speed of 800 to 1200 r / min for 4 to 6 hours in an environment of 35 to 45° C. to prepare the water-based primer;

[0008] The preparation method of the composite conductive material comprises the following steps:

[0009] Hydroxylated multi-walled carbon nanotubes and diethoxy(3-glycidyloxypropyl)methylsilane are heated to 60-65 °C to obtain epoxy-functionalized carbon nanotubes. In an inert gas protection environment, the epoxy-functionalized carbon nanotubes and 1-aminopyrrole are heated to 60-70 °C for reaction to obtain carbon nanotubes containing pyrrole rings; the carbon nanotubes containing pyrrole rings, pyrrole monomers, and anhydrous ferric chloride are stirred and polymerized to prepare the composite conductive material;

[0010] The preparation method of the modified waterborne acrylic resin comprises the following steps:

[0011] cis-2-Butene-1,4-diol and thionyl chloride are stirred and mixed at 0-5 °C, and then L-dopa is added and stirred at 80-90 °C for reaction to obtain an intermediate product; the intermediate product, 1H,1H,2H,2H-heptadecafluorodecyl acrylate, methyl methacrylate, acrylic acid, and butyl acrylate are stirred and mixed to obtain a mixture. In an inert gas protection environment, the mixture and benzoyl peroxide are mixed and reacted at 100-110 °C to prepare the modified waterborne acrylic resin.

[0012] Further, the weight ratio of the hydroxylated multi-walled carbon nanotubes to diethoxy(3-glycidyloxypropyl)methylsilane is 1:6-8.

[0013] Further, the weight ratio of the epoxy-functionalized carbon nanotubes to 1-aminopyrrole is 1:3-5.

[0014] Further, the weight ratio of the carbon nanotubes containing pyrrole rings, pyrrole monomers, and anhydrous ferric chloride is 1:0.5-2.5:0.3-0.8.

[0015] Further, the weight ratio of cis-2-butene-1,4-diol, thionyl chloride, and L-dopa is 1:0.5-0.6:0.4-0.6.

[0016] Further, the weight ratio of the intermediate product, 1H,1H,2H,2H-heptadecafluorodecyl acrylate, methyl methacrylate, acrylic acid, and butyl acrylate is 1-2:0.2-0.3:1-1.5:0.8-1.2:1.5-2.

[0017] Further, the weight ratio of the mixture to benzoyl peroxide is 10-20:0.2-0.3.

[0018] Further, the inert gas is nitrogen or argon.

[0019] Further, the weight ratio of the composite conductive material, modified waterborne acrylic resin, dispersant, and first solvent is 10-20:20-30:2-4:30-50.

[0020] Further, the dispersant is polyvinylpyrrolidone, polyacrylic acid or 2-hydroxyphosphonoacetic acid.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0022] (1) First, the present invention uses an epoxy group-containing silane coupling agent to react with carbon nanotubes to obtain epoxy group-containing carbon nanotubes. Subsequently, the epoxy group in the epoxy group-containing carbon nanotubes reacts with the amino group in 1-aminopyrrole to obtain pyrrole ring-containing carbon nanotubes. On this basis, the pyrrole ring in the pyrrole ring-containing carbon nanotubes further undergoes a polymerization reaction with pyrrole monomers to form polypyrrole, which wraps the carbon nanotubes, thereby preparing a composite conductive material. The composite conductive material exhibits a core-shell structure, where the carbon nanotubes serve as the core part and inherently have excellent electrical conductivity; while polypyrrole serves as the shell part, which not only effectively improves the dispersion of the carbon nanotubes, reduces the agglomeration phenomenon, enabling them to uniformly adhere to the surface of the lithium battery foil, but also polypyrrole itself is a highly conductive polymer. After wrapping the carbon nanotubes, it not only does not reduce the original conductivity but also plays a synergistic effect, further enhancing the overall electrical conductivity of the composite conductive material, thereby contributing to improving the electrical conductivity of the lithium battery foil.

[0023] (2) The present invention grafts levodopa onto cis-2-butene-1,4-diol through an esterification reaction to obtain an intermediate product, and then prepares a modified waterborne acrylic resin through polymerization. The catechol structure in levodopa not only enhances the adhesion between the modified waterborne acrylic resin and the lithium battery foil but also improves the adhesion and durability of the waterborne primer; in addition, the side chain of the modified waterborne acrylic resin is rich in C-F bonds, endowing the waterborne primer with good chemical resistance and high-temperature resistance, effectively preventing the lithium battery foil from being corroded by the electrolyte, thereby providing effective protection for the lithium battery foil.

[0024] (3) A waterborne primer for a lithium battery foil involved in the present invention achieves the goal of forming an efficient coating on the surface of the lithium battery foil through a clever formulation design. The waterborne primer is prepared by mixing and stirring a composite conductive material, a modified waterborne acrylic resin, a dispersant, and a first solvent. After being coated on the lithium battery foil and dried, the formed coating can significantly enhance the various properties of the foil. The composite conductive material and the modified waterborne acrylic resin jointly act on the surface of the foil to form a conductive network, which not only effectively reduces the contact resistance between the active material and the foil but also significantly improves the overall electrical conductivity of the foil, providing a strong guarantee for the efficient operation of the lithium battery. Detailed implementation manners

[0025] The technical solutions of the present invention will be clearly and completely described below through embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0026] Unless otherwise specified, the raw materials and reagents used in the present invention below are all commercially available products, or can be prepared by known methods.

[0027] Hydroxylated multi-walled carbon nanotubes were purchased from the Carbon Nanotube Development Center of Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences.

[0028] Preparation Example 1:

[0029] Preparation of the composite conductive material, including the following steps:

[0030] Disperse 5 parts by weight of hydroxylated multi-walled carbon nanotubes in 500 parts by weight of toluene by ultrasonic treatment at a power of 100 W for 10 min, heat up to 60 °C, add 30 parts by weight of diethoxy(3-glycidoxypropyl)methylsilane, reflux and stir at a speed of 300 r / min for 10 h, then filter with an organic filter membrane, wash 3 times with water and acetone, and vacuum dry at 60 °C for 12 h to obtain epoxy carbon nanotubes; disperse 10 parts by weight of epoxy carbon nanotubes and 30 parts by weight of 1-aminopyrrole in 500 parts by weight of methanol by ultrasonic treatment at a power of 100 W for 10 min, under a nitrogen protection environment, heat up to 60 °C and stir and react at a speed of 600 r / min for 2 h, then wash and dry to obtain carbon nanotubes containing pyrrole rings; disperse 10 parts by weight of carbon nanotubes containing pyrrole rings and 3 parts by weight of anhydrous ferric chloride in 500 parts by weight of a second solvent (V 去离子水 and V 甲醇 = 4:1), then add 5 parts by weight of pyrrole monomer and stir and polymerize at a speed of 500 r / min at 23 °C for 25 h, then wash 3 times with deionized water and ethanol, and dry at 60 °C for 24 h to obtain the composite conductive material.

[0031] Preparation Example 2:

[0032] Preparation of the composite conductive material, including the following steps:

[0033] 5 parts by weight of hydroxylated multi-walled carbon nanotubes were dispersed in 500 parts by weight of toluene by ultrasonic treatment at a power of 120 W for 15 min. After heating to 61 °C, 33 parts by weight of diethoxy(3-glycidyloxypropyl)methylsilane was added. After reflux stirring at a speed of 350 r / min for 11 h, it was filtered through an organic filter membrane, washed 3 times with water and acetone, and vacuum dried at 60 °C for 12 h to obtain epoxy-functionalized carbon nanotubes; 10 parts by weight of epoxy-functionalized carbon nanotubes and 35 parts by weight of 1-aminopyrrole were dispersed in 500 parts by weight of methanol by ultrasonic treatment at a power of 130 W for 15 min. In an argon protective environment, after heating to 62 °C and stirring and reacting at a speed of 700 r / min for 2.4 h, it was washed and dried to obtain carbon nanotubes containing pyrrole rings; 10 parts by weight of carbon nanotubes containing pyrrole rings and 5 parts by weight of anhydrous ferric chloride were dispersed in 500 parts by weight of a second solvent (V 去离子水 and V 甲醇 = 4:1) by ultrasonic treatment at a power of 120 W for 18 min. Then, 10 parts by weight of pyrrole monomer was added and stirred and polymerized at a speed of 600 r / min at 24 °C for 27 h. After washing 3 times with deionized water and ethanol and drying at 60 °C for 24 h, a composite conductive material was prepared.

[0034] Preparation Example 3:

[0035] Preparation of the composite conductive material, comprising the following steps:

[0036] 5 parts by weight of hydroxylated multi-walled carbon nanotubes were dispersed in 500 parts by weight of toluene by ultrasonic treatment at a power of 160 W for 20 min. After heating to 63 °C, 35 parts by weight of diethoxy(3-glycidyloxypropyl)methylsilane was added. After reflux stirring at a speed of 450 r / min for 11 h, it was filtered through an organic filter membrane, washed 3 times with water and acetone, and vacuum dried at 60 °C for 12 h to obtain epoxy-functionalized carbon nanotubes; 10 parts by weight of epoxy-functionalized carbon nanotubes and 45 parts by weight of 1-aminopyrrole were dispersed in 500 parts by weight of methanol by ultrasonic treatment at a power of 180 W for 25 min. In an argon protective environment, after heating to 68 °C and stirring and reacting at a speed of 800 r / min for 2.7 h, it was washed and dried to obtain carbon nanotubes containing pyrrole rings; 10 parts by weight of carbon nanotubes containing pyrrole rings and 7 parts by weight of anhydrous ferric chloride were dispersed in 500 parts by weight of a second solvent (V 去离子水 and V 甲醇 = 4:1) by ultrasonic treatment at a power of 180 W for 25 min. Then, 20 parts by weight of pyrrole monomer was added and stirred and polymerized at a speed of 800 r / min at 24 °C for 28 h. After washing 3 times with deionized water and ethanol and drying at 60 °C for 24 h, a composite conductive material was prepared.

[0037] Preparation Example 4:

[0038] Preparation of the composite conductive material, comprising the following steps:

[0039] 5 parts by weight of hydroxylated multi-walled carbon nanotubes were dispersed in 500 parts by weight of toluene by ultrasonic treatment at a power of 200 W for 30 min. After heating to 65 °C, 40 parts by weight of diethoxy(3-glycidoxypropyl)methylsilane was added. After reflux stirring at a speed of 500 r / min for 12 h, it was filtered through an organic filter membrane, washed 3 times with water and acetone, and vacuum dried in an environment at 60 °C for 12 h to obtain epoxy-functionalized carbon nanotubes; 10 parts by weight of epoxy-functionalized carbon nanotubes and 50 parts by weight of 1-aminopyrrole were dispersed in 500 parts by weight of methanol by ultrasonic treatment at a power of 200 W for 30 min. In a nitrogen protection environment, after heating to 70 °C and stirring and reacting at a speed of 900 r / min for 3 h, it was washed and dried to obtain carbon nanotubes containing pyrrole rings; 10 parts by weight of carbon nanotubes containing pyrrole rings and 8 parts by weight of anhydrous ferric chloride were dispersed in 500 parts by weight of a second solvent (V 去离子水 and V 甲醇 = 4:1) by ultrasonic treatment at a power of 200 W for 30 min. Then, 25 parts by weight of pyrrole monomer was added and stirred and polymerized at a speed of 1000 r / min in an environment at 25 °C for 30 h. After washing 3 times with deionized water and ethanol, it was dried in an environment at 60 °C for 24 h to prepare a composite conductive material.

[0040] Preparation Example 5:

[0041] Preparation of modified waterborne acrylic resin, including the following steps:

[0042] 5 parts by weight of thionyl chloride was added to 10 parts by weight of cis-2-butene-1,4-diol. After stirring at a speed of 500 r / min in an environment at 0 °C for 0.5 h, 4 parts by weight of L-dopa was added, and the temperature was raised to 80 °C and refluxed for 6 h to obtain an intermediate product; 10 parts by weight of the intermediate product, 2 parts by weight of 1H,1H,2H,2H-heptadecafluorodecyl acrylate, 10 parts by weight of methyl methacrylate, 8 parts by weight of acrylic acid, and 15 parts by weight of butyl acrylate were stirred and mixed at a speed of 200 r / min for 15 min to obtain a mixture; in a nitrogen protection environment, 10 parts by weight of the above mixture and 0.2 parts by weight of benzoyl peroxide were dispersed in 100 parts by weight of n-butanol. After heating to 100 °C, it was refluxed for 6 h to prepare a modified waterborne acrylic resin.

[0043] Preparation Example 6:

[0044] Preparation of modified waterborne acrylic resin, including the following steps:

[0045] 5.3 parts by weight of thionyl chloride was added to 10 parts by weight of cis-2-butene-1,4-diol, and the mixture was stirred at a speed of 550 r / min in an environment of 2 °C for 0.8 h. Then, 5 parts by weight of levodopa was added, and the temperature was raised and stirred to 83 °C for reflux reaction for 6.5 h to obtain an intermediate product; 12 parts by weight of the intermediate product, 2.3 parts by weight of 1H,1H,2H,2H-heptadecafluorodecyl acrylate, 11 parts by weight of methyl methacrylate, 10 parts by weight of acrylic acid, and 18 parts by weight of butyl acrylate were stirred and mixed at a speed of 230 r / min for 20 min to obtain a mixture; in an argon protection environment, 13 parts by weight of the above mixture and 0.23 parts by weight of benzoyl peroxide were dispersed in 100 parts by weight of n-butanol, and the temperature was raised to 105 °C and then refluxed for 7 h to prepare a modified waterborne acrylic resin.

[0046] Preparation Example 7:

[0047] The preparation of the modified waterborne acrylic resin includes the following steps:

[0048] 5.8 parts by weight of thionyl chloride was added to 10 parts by weight of cis-2-butene-1,4-diol, and the mixture was stirred at a speed of 600 r / min in an environment of 3 °C for 0.8 h. Then, 5.5 parts by weight of levodopa was added, and the temperature was raised and stirred to 87 °C for reflux reaction for 7.5 h to obtain an intermediate product; 18 parts by weight of the intermediate product, 2.8 parts by weight of 1H,1H,2H,2H-heptadecafluorodecyl acrylate, 13 parts by weight of methyl methacrylate, 11 parts by weight of acrylic acid, and 18 parts by weight of butyl acrylate were stirred and mixed at a speed of 280 r / min for 25 min to obtain a mixture; in an argon protection environment, 18 parts by weight of the above mixture and 0.28 parts by weight of benzoyl peroxide were dispersed in 100 parts by weight of n-butanol, and the temperature was raised to 108 °C and then refluxed for 7.5 h to prepare a modified waterborne acrylic resin.

[0049] Preparation Example 8:

[0050] The preparation of the modified waterborne acrylic resin includes the following steps:

[0051] 6 parts by weight of thionyl chloride was added to 10 parts by weight of cis-2-butene-1,4-diol, and the mixture was stirred at a speed of 700 r / min in an environment of 5 °C for 1 h. Then, 6 parts by weight of levodopa was added, and the temperature was raised and stirred to 90 °C for reflux reaction for 8 h to obtain an intermediate product; 20 parts by weight of the intermediate product, 3 parts by weight of 1H,1H,2H,2H-heptadecafluorodecyl acrylate, 15 parts by weight of methyl methacrylate, 12 parts by weight of acrylic acid, and 20 parts by weight of butyl acrylate were stirred and mixed at a speed of 300 r / min for 30 min to obtain a mixture; in a nitrogen protection environment, 20 parts by weight of the above mixture and 0.3 parts by weight of benzoyl peroxide were dispersed in 100 parts by weight of n-butanol, and the temperature was raised to 110 °C and then refluxed for 8 h to prepare a modified waterborne acrylic resin.

[0052] Preparation Example 9:

[0053] Preparation of modified waterborne acrylic resin, comprising the following steps:

[0054] Mix 15 parts by weight of methyl methacrylate, 12 parts by weight of acrylic acid and 20 parts by weight of butyl acrylate at a stirring speed of 300 r / min for 30 min to obtain a mixture; in a nitrogen protection environment, disperse 20 parts by weight of the above mixture and 0.3 parts by weight of benzoyl peroxide in 100 parts by weight of n-butanol, heat up to 110 °C and reflux for 8 h to prepare the modified waterborne acrylic resin.

[0055] Example 1:

[0056] Preparation of an aqueous primer for lithium battery foils, comprising the following steps:

[0057] Add 10 parts by weight of the composite conductive material prepared in Preparation Example 1, 20 parts by weight of the modified waterborne acrylic resin prepared in Preparation Example 5 and 2 parts by weight of polyvinylpyrrolidone to 30 parts by weight of a first solvent (V 去离子水 :V 乙醇 =5:1), and stir and mix at a speed of 800 r / min in an environment of 35 °C for 4 h to prepare the aqueous primer.

[0058] Example 2:

[0059] Preparation of an aqueous primer for lithium battery foils, comprising the following steps:

[0060] Add 13 parts by weight of the composite conductive material prepared in Preparation Example 2, 22 parts by weight of the modified waterborne acrylic resin prepared in Preparation Example 6 and 2.5 parts by weight of polyacrylic acid to 35 parts by weight of a first solvent (V 去离子水 :V 乙醇 =5:1), and stir and mix at a speed of 900 r / min in an environment of 38 °C for 4.5 h to prepare the aqueous primer.

[0061] Example 3:

[0062] Preparation of an aqueous primer for lithium battery foils, comprising the following steps:

[0063] Add 16 parts by weight of the composite conductive material prepared in Preparation Example 3, 25 parts by weight of the modified waterborne acrylic resin prepared in Preparation Example 7 and 3 parts by weight of 2-hydroxyphosphonoacetic acid to 40 parts by weight of a first solvent (V 去离子水 :V 乙醇 =5:1), and stir and mix at a speed of 1000 r / min in an environment of 42 °C for 5 h to prepare the aqueous primer.

[0064] Example 4:

[0065] Preparation of an aqueous primer for lithium battery foils, comprising the following steps:

[0066] Add 20 parts by weight of the composite conductive material prepared in Preparation Example 4, 30 parts by weight of the modified aqueous acrylic resin prepared in Preparation Example 8, and 4 parts by weight of 2-hydroxyphosphonoacetic acid to 50 parts by weight of a first solvent (V 去离子水 :V 乙醇 = 5:1), and stir and mix at a rotation speed of 1200 r / min in an environment of 45 °C for 6 h to obtain the aqueous primer.

[0067] Comparative Example 1:

[0068] Preparation of an aqueous primer for lithium battery foils, comprising the following steps:

[0069] Add 20 parts by weight of carbon nanotubes, 30 parts by weight of the modified aqueous acrylic resin prepared in Preparation Example 8, and 4 parts by weight of 2-hydroxyphosphonoacetic acid to 50 parts by weight of a first solvent (V 去离子水 :V 乙醇 = 5:1), and stir and mix at a rotation speed of 1200 r / min in an environment of 45 °C for 6 h to obtain the aqueous primer.

[0070] Comparative Example 2:

[0071] Preparation of an aqueous primer for lithium battery foils, comprising the following steps:

[0072] Add 20 parts by weight of the composite conductive material prepared in Preparation Example 4, 30 parts by weight of the modified aqueous acrylic resin prepared in Preparation Example 9, and 4 parts by weight of 2-hydroxyphosphonoacetic acid to 50 parts by weight of a first solvent (V 去离子水 :V 乙醇 = 5:1), and stir and mix at a rotation speed of 1200 r / min in an environment of 45 °C for 6 h to obtain the aqueous primer.

[0073] Comparative Example 3:

[0074] Preparation of an aqueous primer for lithium battery foils, comprising the following steps:

[0075] Add 10 parts by weight of carbon nanotubes, 10 parts by weight of polypyrrole, 30 parts by weight of the modified aqueous acrylic resin prepared in Preparation Example 8, and 4 parts by weight of 2-hydroxyphosphonoacetic acid to 50 parts by weight of a first solvent (V 去离子水 :V 乙醇 = 5:1), and stir and mix at a rotation speed of 1200 r / min in an environment of 45 °C for 6 h to obtain the aqueous primer.

[0076] Comparative Example 4:

[0077] Preparation of an aqueous primer for lithium battery foils, comprising the following steps:

[0078] Add 20 parts by weight of the composite conductive material prepared in Preparation Example 4, 25 parts by weight of the modified aqueous acrylic resin prepared in Preparation Example 9, 3 parts by weight of L - dopa, and 4 parts by weight of 2 - hydroxyphosphonoacetic acid to 50 parts by weight of a first solvent (V 去离子水 :V 乙醇 = 5:1), and stir - mix at a speed of 1200 r / min in an environment of 45°C for 6 h to obtain the aqueous primer.

[0079] Performance detection test:

[0080] Coat the aqueous primers prepared in Examples 1 - 4 and Comparative Examples 1 - 4 on aluminum foils respectively, vacuum - dry at 60°C for 3 h, and then heat up to 120°C and dry for 2 h to obtain 8 kinds of aluminum foils for lithium batteries. Perform performance detection on the above - obtained 8 kinds of aluminum foils for lithium batteries:

[0081] 1. Conductivity detection: Use a Changzhou Anber AT256 type probe tester to detect the resistance of the above - mentioned 8 kinds of aluminum foils for lithium batteries. The detection results are shown in Table 1;

[0082] 2. Adhesion detection: Coat lithium iron phosphate slurry on the above - mentioned 8 kinds of aluminum foils for lithium batteries respectively to make electrodes with a surface density of 300 g / m 2 and a tap density of 2.4 g / cm 3 , and test the adhesion of the electrodes. The detection results are shown in Table 1.

[0083] 3. Electrolyte resistance performance detection: The electrolyte composition is EC:EDC = 1:1, and the concentration of LiPF 6 is 1 M. Immerse the above - mentioned 8 kinds of aluminum foils for lithium batteries in the electrolyte in a sealed manner at 85°C for 24 h, wipe off the electrolyte with water, and observe the surface corrosion situation. The detection results are shown in Table 1.

[0084] Table 1. Performance detection

[0085] Resistance (Ω) Adhesion force (N) Electrolyte resistance Example 1 1.5 0.81 Good Example 2 1.3 0.85 Good Example 3 1.1 0.87 Good Example 4 0.9 0.89 Good Comparative example 1 2.5 0.53 Average Comparative example 2 1.9 0.26 Poor Comparative example 3 2.1 0.67 Average Comparative example 4 1.7 0.37 Poor

[0086] According to the data in Table 1, it can be clearly observed that the water-based primer coatings prepared in Examples 1 to 4 exhibit good performance after being coated on the aluminum foil of lithium batteries. Compared with Comparative Examples 1 to 4, Examples 1 to 4 have lower resistance, stronger adhesion, and better electrolyte resistance. These results fully demonstrate the superiority of the water-based primer coatings prepared in Examples 1 to 4 in terms of electrochemical performance, adhesion, and electrolyte resistance. Further comparing Comparative Examples 1 to 4 with Example 4, it can be found that there is a decline in all aspects of electrochemical performance, adhesion, and electrolyte resistance. This phenomenon indicates that there is a significant synergistic effect among the various materials used in Examples 1 to 4, and this effect acts together to improve the overall performance of the water-based primer coating.

[0087] The above-described embodiments have detailed the technical solutions and beneficial effects of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not used to limit the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed.

Claims

1. A method for preparing a water-based primer for lithium battery foil, characterized in that: The preparation method comprises the following steps: The composite conductive material, modified water-based acrylic resin and dispersant are added to the first solvent, and stirred and mixed at a speed of 800 to 1200 r / min for 4 to 6 hours in an environment of 35 to 45° C. to prepare the water-based primer; The preparation method of the composite conductive material comprises the following steps: Hydroxylated multi-walled carbon nanotubes and diethoxy (3-glycidyloxypropyl) methyl silane are mixed and heated to 60-65°C to obtain epoxy carbon nanotubes; epoxy carbon nanotubes and 1-aminopyrrole are mixed and heated to 60-70°C in an inert gas protection environment to obtain pyrrole ring-containing carbon nanotubes; pyrrole ring-containing carbon nanotubes, pyrrole monomers and anhydrous ferric chloride are stirred and polymerized to obtain the composite conductive material; The preparation method of the modified waterborne acrylic resin comprises the following steps: After cis-2-butene-1,4-diol and thionyl chloride are stirred and mixed at 0-5°C, levodopa is added and stirred and reacted at 80-90°C to obtain an intermediate product; the intermediate product, 1H,1H,2H,2H-heptadecafluorodecyl acrylate, methyl methacrylate, acrylic acid and butyl acrylate are stirred and mixed to obtain a mixture, and in an inert gas protection environment, the mixture is mixed and reacted with benzoyl peroxide at 100-110°C to obtain the modified waterborne acrylic resin.

2. The method for preparing a water-based primer for lithium battery foil according to claim 1, characterized in that: The weight ratio of the hydroxylated multi-walled carbon nanotubes to diethoxy (3-glycidyloxypropyl) methyl silane is 1:6-8.

3. The method for preparing a water-based primer for lithium battery foil according to claim 1, characterized in that: The weight ratio of the epoxy carbon nanotubes to 1-aminopyrrole is 1:3-5.

4. The method for preparing a water-based primer for lithium battery foil according to claim 1, characterized in that: The weight ratio of the pyrrole ring-containing carbon nanotubes, the pyrrole monomer and the anhydrous ferric chloride is 1:0.5-2.5:0.3-0.

8.

5. The method for preparing a water-based primer for lithium battery foil according to claim 1, characterized in that: The weight ratio of the cis-2-butene-1,4-diol, thionyl chloride and levodopa is 1:0.5-0.6:0.4-0.

6.

6. The method for preparing a water-based primer for lithium battery foil according to claim 1, characterized in that: The weight ratio of the intermediate product, 1H,1H,2H,2H-heptadecafluorodecyl acrylate, methyl methacrylate, acrylic acid and butyl acrylate is 1-2: 0.2-0.3: 1-1.5: 0.8-1.2: 1.5-2.

7. The method for preparing a water-based primer for lithium battery foil according to claim 1, characterized in that: The weight ratio of the mixture to benzoyl peroxide is 10-20:0.2-0.

3.

8. The method for preparing a water-based primer for lithium battery foil according to claim 1, characterized in that: The weight ratio of the composite conductive material, the modified waterborne acrylic resin, the dispersant and the first solvent is 10-20:20-30:2-4:30-50.