Aqueous polyamide lithium battery separator and method of making the same

Abstract

The application discloses a kind of water-based polyamide lithium battery diaphragm and preparation method thereof, which comprises the following steps: mixing sulfonated diamine, triethylamine and organic solvent under inert gas atmosphere, then heating to 60-70 DEG C to obtain sulfonic acid ammonium salt diamine solution; the sulfonic acid ammonium salt diamine solution is cooled to-10 DEG C-20 DEG C, furan diformyl chloride is added to react, to obtain material; then the slurry is mixed with alkali to obtain sulfonic acid furan polyamide; the sulfonic acid furan polyamide is diluted to 2wt%-5wt% solid content of dilute solution; the dilute solution is mixed with water, then emulsified, and the organic solvent in the sulfonic acid furan polyamide is removed to obtain a mixed solution, which is then mixed with inorganic particles and dispersant to obtain water-based coating slurry; the water-based coating slurry is sprayed from the nozzle by electrospinning equipment, and the attached fibers on the base film of the collecting roller are collected, then washed and dried to obtain the water-based polyamide lithium battery diaphragm.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of battery separator, in particular to a water-based polyamide lithium battery separator and a preparation method thereof. BACKGROUND

[0002] In recent years, with the rapid development of new energy vehicles, lithium batteries have become a crucial research field. As the power source of new energy vehicles, the safety and performance of lithium batteries are increasingly valued. The separator plays a key role in the battery, mainly separating the positive and negative electrodes to prevent short circuits, while allowing ions to pass through to complete the charging and discharging process of the battery.

[0003] At present, most of the commercial separators are polyolefin separators, and common polyolefin separator materials include polyethylene (PE) and polypropylene (PP). In order to further improve the performance of the separator, the polyolefin separator is usually coated with a film, and common film materials include ceramic coatings and functional polymer coatings. Some researchers dissolve aromatic polyamide in ordinary organic solvents to form a slurry, which is then coated on the surface of the polyolefin separator.

[0004] However, the existing coated separators still have the problems of low mechanical properties and poor ability to absorb and adsorb ions such as nickel, cobalt and manganese in the battery, which can cause the positive material to be easily precipitated, thereby affecting the safety and service life of the battery. SUMMARY

[0005] To solve the above technical problems, one object of the present application is to provide a water-based polyamide lithium battery separator and a preparation method thereof. The lithium battery separator has high mechanical properties, good thermal shrinkage properties, high film breaking temperature, and improved peel strength, thereby improving the safety performance and service life of the battery.

[0006] In one aspect of the present application, a preparation method of a water-based polyamide lithium battery separator is provided. According to an embodiment of the present application, the method comprises:

[0007] Step 1. In an inert gas atmosphere, sulfonated diamine, triethylamine and organic solvent are mixed, then heated to 60-70℃ for reaction to obtain an ammonium sulfonate diamine solution; the ammonium sulfonate diamine solution is cooled to -10℃-20℃, furan dicarboxylic acid chloride is added for reaction to obtain a slurry; the slurry is mixed with a base to obtain a sulfonic acid-based furan polyamide;

[0008] Step 2. Dilute the sulfonic acid-based furan polyamide to a dilute solution with a solid content of 2wt%-5wt%;

[0009] Step 3, mixing the dilute solution with water, then emulsifying, and then removing the organic solvent in the sulfonic acid furan polyamide to obtain a mixed solution, and then mixing with inorganic particles and a dispersant to obtain an aqueous coating slurry;

[0010] Step 4, spraying the aqueous coating slurry from a nozzle through an electrospinning device, collecting the attached fibers on a base film of a collection roller, and then washing and drying to obtain an aqueous polyamide lithium battery separator.

[0011] The sulfonated diamine and triethylamine are mixed with an organic solvent, and then reacted at a temperature of 60-70 DEG C. The sulfonated diamine and triethylamine react to form an ammonium sulfonate diamine. The ammonium sulfonate diamine has stronger polarity, can be better dissolved in a polar organic solvent, and can polymerize with furan diformyl chloride, thereby grafting the sulfonic acid group in the polyamide and increasing the content of the sulfonic acid group in the polyamide.

[0012] The sulfonic acid polyamide is diluted to obtain a dilute solution, mixed with water, further emulsified, and then the residual organic solvent is removed using a separation device to obtain an aqueous mixed solution; and then mixed with inorganic particles and a dispersant to obtain an aqueous coating slurry.

[0013] Meanwhile, the electrospinning method is used to collect the sprayed fibers of the aqueous coating slurry on a base film to obtain a lithium battery separator. The sulfonic acid furan polymer is attached to the base film by electrospinning, which can effectively improve the mechanical properties and thermal shrinkage properties of the separator, and the process is simple and efficient.

[0014] In summary, the lithium battery separator has high mechanical properties, good thermal shrinkage properties, high film breaking temperature, and improved peel strength, thereby improving the safety performance and service life of the battery.

[0015] In addition, the preparation method of the aqueous polyamide lithium battery separator according to the present application can also have the following additional technical features:

[0016] In some embodiments of the present application, the molar ratio of the triethylamine to the sulfonated diamine is (1.1-2.5):1.

[0017] In some embodiments of the present application, the molar ratio of the sulfonated diamine to the furan diformyl chloride is (1-2.5):1.

[0018] In some embodiments of the present application, the mass ratio of the organic solvent to the sulfonated diamine is (3-11):1.

[0019] In some embodiments of the present application, the inert gas is one or more of nitrogen, helium and argon, the organic solvent is one or more of toluene, N,N-dimethylacetamide, N-methylpyrrolidone, N,N-dimethylformamide, dichloromethane and dichloroethane, and the sulfonated diamine is one or more of 2,5-diaminobenzenesulfonic acid and 4,4'-diamino-3,3'-biphenyl disulfonic acid.

[0020] In some embodiments of the present application, the pH of the slurry after mixing with the base is 6-8, and the base comprises at least one of lithium hydroxide, calcium hydroxide and sodium hydroxide.

[0021] In some embodiments of the present application, the mass ratio of the dilute solution to water is (1.5-10):1.

[0022] In some embodiments of the present application, the inorganic particles are one or more of alumina and boehmite with a particle size of 100 nm-5 μm, the adhesive is one or more of polyacrylate, modified polyacrylate and modified polyvinyl alcohol, the thickening agent is sodium carboxymethyl cellulose, and the dispersant is one or more of acrylate, modified acrylate and acrylic polymer.

[0023] In some embodiments of the present application, the mass of the mixed solution is 5%-30% of the mass of the aqueous coating slurry, the mass of the inorganic particles is 5%-20% of the mass of the mixed solution, and the mass of the dispersant is 0.5%-1.5% of the mass of the mixed solution.

[0024] In some embodiments of the present application, before being input into the electrospinning device, the aqueous coating slurry is mixed with a thickening agent, an adhesive, a wetting agent and an adhesion promoter, the mass of the thickening agent is 0.01-0.1% of the mass of the aqueous coating slurry, the mass of the wetting agent is 0.01%-1% of the mass of the aqueous coating slurry, the mass of the adhesive is 1%-10% of the mass of the mixed solution, and the mass of the adhesion promoter is 0.01%-0.05% of the mass of the aqueous coating slurry.

[0025] In some embodiments of the present application, the wetting agent is one or more of fatty alcohol polyoxyethylene ether and polyether-modified organosilicon, and the adhesion promoter is a sulfate salt anionic surfactant.

[0026] In some embodiments of the present application, the preparation conditions include a high voltage of 15-30 KV, a spinning rate of 0.5-3.0 ml / h, an ambient humidity of ≤30%, and a distance between the spinning nozzle and the receiving plate of 10-20 cm.

[0027] In a second aspect, the present application provides a water-based polyamide lithium battery separator prepared by the above method.

[0028] Additional aspects and advantages of the present application will be made apparent from the following description. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, not all. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of the present application. EMBODIMENT

[0030] Preparation of the water-based polyamide lithium battery separator:

[0031] Step one: under a nitrogen atmosphere, 10 kg of dimethylacetamide (organic solvent) is added to a reaction kettle, then 1 kg of triethylamine and 1 kg of 2,5-diaminobenzene sulfonic acid (sulfonated diamine) are added to react at 60°C to obtain an ammonium sulfonate diamine solution; the ammonium sulfonate diamine solution is cooled to -10°C, then 1 kg of furan diacyl chloride is added in portions for polymerization, the polymerization is completed after 4 hours, then 0.75 kg of calcium hydroxide (base) is added for neutralization, and after the neutralization is completed, a sulfonic acid-based furan polyamide is obtained.

[0032] Step two: the sulfonic acid-based furan polyamide is diluted to 2 wt% solid content with dimethylacetamide, then 10.8 times the mass of water is added, after stirring and dispersing uniformly, an equal amount of water is emulsified by an emulsifying pump, then dimethylacetamide is removed by a ceramic membrane separation device to obtain a mixed solution.

[0033] Step three: 14 kg of deionized water, 6 kg of the mixed solution, and 0.06 kg of modified acrylate (dispersant) are added to a stirring tank and high-speed dispersed for 30 minutes; after the dispersion is completed, 0.6 kg of alumina (inorganic particles) with a particle size of 0.6 μm is added and high-speed dispersed for 1 hour; after the dispersion is completed, a sand mill is used for grinding 3 times to obtain a water-based coating slurry.

[0034] Step four: using an electrostatic spinning device, the water-based coating slurry is sprayed from a nozzle in a high-voltage electrostatic field by a micro-injection pump to form a dense nanocomposite film on the base film PE film of a collection roller, then washed and dried to obtain a water-based polyamide lithium battery separator, wherein the spinning rate is 2.0 ml / h, the environmental humidity is ≤30%, and the distance between the spinning nozzle and the receiving plate is 15 cm. EMBODIMENT

[0035] Preparation of water-based polyamide lithium battery separator:

[0036] Step one: under the atmosphere of nitrogen, 10 kg of dimethylacetamide (organic solvent) was added into the reaction kettle, then 1 kg of triethylamine and 1 kg of 4,4'-diamino-3,3'-biphenyl disulfonic acid (sulfonated diamine) were added to react at 65°C to obtain sulfonic acid ammonium salt diamine solution; the sulfonic acid ammonium salt diamine solution was cooled to -5°C, then 1 kg of furan diacyl chloride was added in batches to carry out polymerization reaction, after 4 hours of polymerization reaction, 0.75 kg of calcium hydroxide (base) was added for neutralization, and after the neutralization was completed, sulfonic acid furan polyamide was obtained.

[0037] Step two: the sulfonic acid furan polyamide was diluted to 2wt% solid content with dimethylacetamide, then 9.8 times mass of water of solid content was added, after stirring and uniformly dispersing, the same amount of water was emulsified by an emulsifying pump, dimethylacetamide was removed by using ceramic membrane separation equipment, and a mixed solution was obtained.

[0038] Step three: 14 kg of deionized water, 6 kg of mixed solution, and 0.06 kg of modified acrylate (dispersant) were added into a stirring tank and high-speed dispersed for 30 minutes; after the dispersion was completed, 0.6 kg of aluminum oxide (inorganic particles) with a particle size of 0.6 μm was added and high-speed dispersed for 1 hour; after the dispersion was completed, a sand mill was used for grinding for 3 times, and a water-based coating slurry was obtained.

[0039] Step four: using an electrostatic spinning device, the water-based coating slurry was sprayed from a nozzle in a high-voltage electrostatic field by a micro-injection pump to form a dense nanocomposite film on the base film PE film of the collecting roller, and then the film was washed and dried to obtain a water-based polyamide lithium battery separator, wherein the spinning rate was 2.0 ml / h, the environmental humidity was ≤30%, and the distance between the spinning nozzle and the receiving plate was 15 cm. Example

[0040] Preparation of water-based polyamide lithium battery separator:

[0041] Step one: under the atmosphere of nitrogen, 10 kg of dimethylacetamide (organic solvent) was added into the reaction kettle, then 1 kg of triethylamine and 1 kg of 2,5-diaminobenzenesulfonic acid (sulfonated diamine) were added to react at 70°C to obtain sulfonic acid ammonium salt diamine solution, the sulfonic acid ammonium salt diamine solution was cooled to -5°C, then 1 kg of furan diacyl chloride was added in batches to carry out polymerization reaction, after 4 hours of polymerization reaction, 0.75 kg of calcium hydroxide (base) was added for neutralization, and after the neutralization was completed, sulfonic acid furan polyamide was obtained.

[0042] Step two: dilute the sulfonic acid furan polyamide to 3wt% solid content with dimethylacetamide, then add 5.4 times mass of water with solid content, stir and disperse uniformly, then emulsify with equal amount of water through an emulsifying pump, and then remove dimethylacetamide using a ceramic membrane separation device to obtain a mixed solution.

[0043] Step three: add 14 kg of deionized water, 6 kg of the mixed solution, and 0.06 kg of modified acrylate (dispersant) into a stirring tank and high-speed disperse for 30 minutes; after dispersion is completed, add 0.6 kg of alumina with a particle size of 0.6 μm (inorganic particles) and high-speed disperse for 1 hour; after dispersion is completed, use a sand mill to grind 3 times, after grinding is completed, add 0.3 kg of modified polyacrylate (adhesive) and medium-speed disperse for 30 minutes, after dispersion is completed, add 0.01 kg of sodium carboxymethyl cellulose (thickening agent) and medium-speed disperse for 30 minutes; after dispersion is completed, add 0.004 kg of polyether modified silicone (wetting agent) and 0.004 kg of sulfate anionic surfactant (adhesion promoter) and stir for 20 minutes to obtain an aqueous coating slurry.

[0044] Step four: use an electrospinning device to spray the aqueous coating slurry from a nozzle in a high-voltage electrostatic field through a micro-injection pump to form a dense nanocomposite film on the base film PE film of the collecting roller, and then clean and dry to obtain an aqueous polyamide lithium battery separator, wherein the spinning rate is 2.5 ml / h, the environmental humidity is ≤30%, and the distance between the spinning nozzle and the receiving plate is 20 cm. Embodiment

[0045] Preparation of an aqueous polyamide lithium battery separator:

[0046] Step one: under a nitrogen atmosphere, add 10 kg of dimethylacetamide (organic solvent) into a reaction kettle, and then add 1 kg of triethylamine and 1 kg of 2,5-diaminobenzene sulfonic acid (sulfonated diamine) to react at a temperature of 65°C to obtain an ammonium sulfonate diamine solution; cool the ammonium sulfonate diamine solution to 5°C, and then add 1 kg of furan diacyl chloride in portions to perform a polymerization reaction, and after 4 hours of reaction, add 0.75 kg of calcium hydroxide (alkali) to perform neutralization, and after neutralization is completed, the sulfonic acid furan polyamide is obtained.

[0047] Step two: dilute the sulfonic acid furan polyamide to 3.5wt% solid content with dimethylacetamide, add 10.8 times mass of water with solid content, stir and disperse uniformly, then emulsify with equal amount of water through an emulsifying pump, and then remove dimethylacetamide using a ceramic membrane separation device to obtain a mixed solution.

[0048] Step three: add 15 kg of deionized water, 6 kg of mixed solution, 0.06 kg of modified acrylate (dispersant) into the stirring tank and high-speed disperse for 30 minutes; after dispersion, add 0.6 kg of boehmite (inorganic particles) with a particle size of 0.6 μm and high-speed disperse for 1 hour; after dispersion, use a sand mill to grind 3 times, after grinding, add 0.6 kg of modified polyacrylate (adhesive) and medium-speed disperse for 30 minutes, after dispersion, add 0.01 kg of sodium carboxymethyl cellulose (thickening agent) and medium-speed disperse for 30 minutes; after dispersion, add 0.004 kg of polyether modified silicone (wetting agent) and 0.004 kg of sulfate anionic surfactant (adhesion promoter) and stir for 20 minutes to obtain the coating slurry of water-based aramid.

[0049] Step four: use an electrospinning device to form a dense nanocomposite film on the base film PE film of the collection roller by injecting the water-based coating slurry from the nozzle in a high-voltage electrostatic field through a micro-injection pump, and then washing and drying to obtain a water-based polyamide lithium battery separator, wherein the spinning rate is 2.5 ml / h, the environmental humidity is ≤30%, and the distance between the spinning nozzle and the receiving plate is 20 cm. Example

[0050] Preparation of water-based polyamide lithium battery separator:

[0051] Step one: under a nitrogen atmosphere, add 10 kg of dimethylacetamide (organic solvent) to the reaction kettle, and then add 1 kg of triethylamine and 1 kg of 2,5-diaminobenzenesulfonic acid for reaction (sulfonated diamine) to obtain an ammonium sulfonate diamine solution at a temperature of 65°C; cool the ammonium sulfonate diamine solution to 5°C, and then add 1 kg of furan diacyl chloride in portions for polymerization reaction, add 0.75 kg of calcium hydroxide (base) for neutralization after 4 hours of polymerization, and then obtain the sulfonic acid-based furan polyamide after neutralization.

[0052] Step two: dilute the sulfonic acid-based furan polyamide to 4 wt% solid content with dimethylacetamide, add 10.8 times the mass of water, stir and disperse uniformly, then emulsify with an equal amount of water through an emulsifying pump, and then use a ceramic membrane separation device to remove dimethylacetamide to obtain a mixed solution.

[0053] Step three: 15 kg of deionized water, 6 kg of mixed solution, 0.05 kg of modified acrylate (dispersant) were added into the stirring tank and dispersed at high speed for 30 minutes; after dispersion, 0.6 kg of alumina particles (inorganic particles) with a particle size of 0.6 μm was added and dispersed at high speed for 1 hour; after dispersion, a sand mill was used for grinding 3 times, and after grinding, 0.9 kg of modified polyacrylate (adhesive) was added and dispersed at medium speed for 30 minutes, and then 0.01 kg of sodium carboxymethyl cellulose (thickening agent) was added and dispersed at medium speed for 30 minutes; after dispersion, 0.004 kg of polyether modified silicone (wetting agent) and 0.004 kg of sulfate anionic surfactant (adhesion promoter) were added and stirred for 20 minutes to obtain the water-based coating slurry.

[0054] Step four: using an electrospinning device, the water-based coating slurry was sprayed from the nozzle in a high-voltage electrostatic field by a micro-injection pump, and a dense nanocomposite film was formed on the base film PE film of the collection roller, and then washed and dried to obtain the water-based polyamide lithium battery separator, wherein the spinning rate was 2.5 ml / h, the environmental humidity was ≤30%, and the distance between the spinning nozzle and the receiving plate was 20 cm.

[0055] Comparative example 1

[0056] Triethylamine was replaced by p-phenylenediamine, and the rest of the process was the same as example 1, and finally a lithium battery separator was obtained.

[0057] Comparative example 2

[0058] Commercial aramid separator

[0059] The separators produced in examples 1-5 and comparative examples 1-2 were tested for the following properties, and the performance test results are shown in Table 1.

[0060] Table 1 Performance comparison of separators obtained in examples 1-5 and comparative examples 1-2

[0061]

[0062] From the performance test data in Table 1, it can be seen that the lithium battery separator prepared based on the application has high mechanical properties, good thermal shrinkage performance, high film breaking temperature, and improved peel strength, and when applied to lithium batteries, it can improve the safety performance and service life of lithium batteries.

[0063] In the description of the specification, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are contained in at least one embodiment or example of the present application. In the specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any suitable manner in any one or more embodiments or examples. In addition, the person skilled in the art can combine and combine the different embodiments or examples described in the specification and the features of the different embodiments or examples without contradiction.

[0064] Although the embodiments of the present application have been shown and described above, it is understood that the above-described embodiments are exemplary and are not to be construed as limiting the present application, and those skilled in the art can make changes, modifications, replacements and variations to the above-described embodiments within the scope of the present application.

Claims

1. A method of preparing an aqueous polyamide lithium battery separator, characterized in that, The application relates to a preparation method of a water-based polyamide lithium battery diaphragm. Step 1: sulfonated diamine, triethylamine and an organic solvent are mixed under an inert gas atmosphere, and then the mixture is heated to 60-70 DEG C to obtain a sulfonic acid ammonium salt diamine solution; the sulfonic acid ammonium salt diamine solution is cooled to-10-20 DEG C, furan dicarboxylic acid chloride is added, and a slurry is obtained; the slurry is mixed with a base to obtain a sulfonic acid furan polyamide; Step 2: the sulfonic acid furan polyamide is diluted into a dilute solution with a solid content of 2-5 wt%; Step 3: the dilute solution is mixed with water, emulsified, and then the organic solvent in the sulfonic acid furan polyamide is removed to obtain a mixed solution, which is then mixed with inorganic particles and a dispersing agent to obtain a water-based coating slurry; Step 4: the water-based coating slurry is sprayed from a nozzle by an electrostatic spinning device, and the attached fibers are collected on a base film of a collecting roller, and then the fibers are cleaned and dried to obtain the water-based polyamide lithium battery diaphragm.

2. The method for preparing an aqueous polyamide lithium battery separator according to claim 1, characterized in that, In step 1, the inert gas is one or more of nitrogen, helium and argon, the organic solvent is one or more of toluene, N, N-dimethylacetamide, N-methylpyrrolidone, N, N-dimethylformamide, dichloromethane and dichloroethane, and the sulfonated diamine is one or more of 2, 5-diaminobenzenesulfonic acid and 4, 4'-diamino-3, 3'-biphenyldisulfonic acid.

3. The method for preparing an aqueous polyamide lithium battery separator according to claim 2, characterized in that, The molar ratio of the triethylamine to the sulfonated diamine is (1.1-2.5):1, and the mass ratio of the organic solvent to the sulfonated diamine is (3-11):

1.

4. The method for preparing an aqueous polyamide lithium battery separator according to claim 2, characterized in that, The molar ratio of the sulfonated diamine to the furan dicarboxylic acid chloride is (1-2.5):

1.

5. The method of claim 1, wherein the aqueous polyamide lithium battery separator is prepared by the steps of: a) providing a polyamide solution; b) providing a lithium salt solution; c) mixing the polyamide solution and the lithium salt solution; d) coating the mixture on a substrate; and e) drying the coated mixture. In step 1, the pH of the slurry after being mixed with the base is 6-8, and the base comprises at least one of lithium hydroxide, calcium hydroxide and sodium hydroxide.

6. The method for preparing an aqueous polyamide lithium battery separator according to claim 1, characterized in that, In step 3, the mass ratio of the dilute solution to water is (1.5-10):

1.

7. The method for preparing an aqueous polyamide lithium battery separator according to claim 1, characterized in that, In step 3, the inorganic particles are one or both of alumina and boehmite with a particle size of 100 nm-5 microns, and the dispersing agent is one or more of acrylate, modified acrylic ester and acrylic polymer.

8. The method of claim 7, wherein the aqueous polyamide lithium battery separator is prepared by the steps of: In step 3, the mass of the mixed solution is 5%-30% of the mass of the water-based coating slurry, the mass of the inorganic particles is 5%-20% of the mass of the mixed solution, and the mass of the dispersing agent is 0.5%-1.5% of the mass of the mixed solution.

9. The method for preparing an aqueous polyamide lithium battery separator according to claim 1, characterized in that, Before being input into the electrostatic spinning device, the water-based coating slurry is mixed with a thickening agent, an adhesive, a wetting agent and an adhesion promoter, the mass of the thickening agent is 0.01-0.1% of the mass of the water-based coating slurry, the mass of the wetting agent is 0.01%-1% of the mass of the water-based coating slurry, the mass of the adhesive is 1%-10% of the mass of the mixed solution, and the mass of the adhesion promoter is 0.01%-0.05% of the mass of the water-based coating slurry.

10. An aqueous polyamide lithium battery separator characterized in that, The water-based polyamide lithium battery diaphragm is prepared by the preparation method in any one of claims 1-9.

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