Coating liquid, lithium ion battery diaphragm and preparation method

Abstract

The invention discloses a coating liquid, a lithium ion battery diaphragm and a preparation method, and the coating liquid comprises the following components in percentage by mass: 2-25% of thiophene polyamide nanofiber, 15-70% of inorganic ceramic, 1-5% of an adhesive, 0.5-5% of an auxiliary agent and the balance of deionized water. Thiophene polyamide has strong hydrogen-bond interaction, high molecular weight and regularity, endows the material with excellent mechanical strength, high modulus and heat resistance, and has good compatibility with electrolyte due to the polarity of amide groups, so that the wettability of the diaphragm is good. The coating liquid contains the thiophene polyamide nanofibers, the large specific surface area of the thiophene polyamide nanofibers can promote absorption of an electrolyte, and the compatibility of the diaphragm and the electrolyte is improved; a uniform coating is formed after coating, is firmly bonded with a base film, has excellent wettability and thermal stability, and can improve the safety of the lithium battery. In addition, the coating liquid is prepared only by mixing raw materials, the process is green and environment-friendly, the operation is simple, the water-based coating cost is lower than that of commercially available oily products, and the method is suitable for industrialization.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of new energy lithium ion batteries, in particular to a coating liquid, a lithium ion battery separator and a preparation method. BACKGROUND

[0002] Lithium ion batteries are widely used due to their high energy density and long cycle life and other excellent characteristics. As one of the core components of lithium ion batteries, the performance indicators of the separator directly affect the overall performance of the battery.

[0003] At present, in order to improve the safety performance of the separator, the market generally adopts a coating modification technology, mainly including inorganic ceramic coating and organic material (such as aramid, PVDF, etc.) coating two types. Among them, the ceramic coating mainly adopts a water-based system, but its safety performance still has certain limitations; and the aramid coating is based on an oily system, which needs to use DMAC, NMP, acetone and other organic solvents, which not only easily causes environmental pollution, but also has problems such as solvent recovery difficulty, high production cost and the like. In addition, the morphology uniformity of the ceramic particles is poor, and the compatibility of the aramid coating layer with the electrode liquid is poor, resulting in the defects of insufficient electrolyte wettability of the water-based ceramic separator and the oily aramid separator.

[0004] In view of this, the present application is proposed. SUMMARY

[0005] The purpose of the present application is to provide a coating liquid, a lithium ion battery separator and a preparation method, which is beneficial to improve the compatibility of the lithium ion battery separator and the electrolyte.

[0006] The present application is realized as follows:

[0007] In a first aspect, the present application provides a coating liquid, which comprises, by mass percentage, 2-25% of thiofene polyamide nanofiber, 15-70% of inorganic ceramic, 1-5% of adhesive, 0.5-5% of additive and the balance of deionized water.

[0008] In an optional embodiment, the adhesive comprises a polymer A obtained by self-polymerization of a monomer according to formula I, and the mass fraction of the polymer A in the coating liquid is 1%-5%; wherein the monomer according to formula I has the following structure:

[0009]

[0010] Wherein, R is one of linear or branched alkylene, cyclic alkylene, arylene and arylene alkylene, and X and Y are chain segments connecting ether oxygen and double bond.

[0011] In an optional embodiment, the monomer of formula I is obtained by reacting isocyanate with at least one of unsaturated hydroxyl compounds selected from N,N"-bis(2-hydroxyethyl)-N"-acryloyl-1,3-diaminopropane, N-(2,3-dihydroxypropyl)-2-propenamide, propenol, 3-buten-1-ol and N-trihydroxymethyl acrylamide in the presence of a catalyst.

[0012] In an optional embodiment, the catalyst is at least one of butyl tin laurate and dimethyl tin acid ester.

[0013] And / or, the reaction temperature is 70-90℃, and the reaction time is 3 hours.

[0014] In an optional embodiment, the polymer A is obtained by polymerization of the monomer of formula I in the presence of an initiator, the polymerization temperature is 75-85℃, the polymerization time is 4.5-5.5 hours, and the initiator is azobisisobutyronitrile.

[0015] In an optional embodiment, the adhesive further comprises at least one of polyacrylic polymer, polyvinyl alcohol, polyurethane polymer and polyimide.

[0016] And / or, the diameter of the thienyl polyamide nanofiber is 20-500 nanometers, and the length is 0.5-50 micrometers.

[0017] And / or, the thienyl polyamide nanofiber is at least one of a polymer of 2,5-thiophenedicarboxylic chloride and m-phenylenediamine, a polymer of 2,5-thiophenedicarboxylic chloride and 4,4-diaminodiphenyl ether, a polymer of 2,5-thiophenedicarboxylic chloride and m-phthaloyl chloride and 4,4-diaminodiphenyl ether, a polymer of 2,5-thiophenedicarboxylic chloride and m-phthaloyl chloride and 4,4"-(1,4-phenylenedioxy)bisbenzene amine, and a polymer of 2,5-thiophenedicarboxylic chloride and 4,4-diaminodiphenyl ether and 2-(4-aminophenyl)-5-aminobenzimidazole.

[0018] And / or, the preparation method of the thienyl polyamide nanofiber comprises electrospinning a spinning dope solution comprising an organic solvent, thienyl polyamide, polyvinyl alcohol and lithium chloride to obtain the nanometer thienyl polyamide.

[0019] And / or, the inorganic carbon ceramic is at least one of alumina, boehmite, silica, zirconia and zinc oxide.

[0020] And / or, the auxiliary agent is at least one of an alcohol compound, a carbonate compound and sodium alkyl sulfonate.

[0021] In an optional embodiment, the inorganic carbon ceramic is selected from at least one of alumina and boehmite;

[0022] And / or, the auxiliary agent is selected from at least one of ethylene glycol, polyethylene glycol and dimethyl carbonate;

[0023] And / or, the conditions of the electrospinning step include: a voltage of 6-10 kV, an extrusion rate of 2-2.2 mL / h, a drawing wind pressure of 0.02-0.055 MPa, a spinneret inner diameter of 0.1-0.3 mm, and a receiving distance of 15-20 cm;

[0024] And / or, the spinning stock solution includes N,N-dimethylformamide 500-900 g / kg, thienyl polyamide 50-100 g / kg, polyvinyl alcohol 10-50 g / kg and lithium chloride 10-50 g / kg.

[0025] In a second aspect, the present application provides a lithium ion battery separator, comprising a base film and a coating layer formed on one side or both sides of the base film, wherein the coating layer is obtained by drying the coating liquid according to any one of the preceding embodiments.

[0026] In an optional embodiment, the base film is selected from one of a PP base film, a PE base film and a PET base film.

[0027] In a third aspect, the present application provides a preparation method of the lithium ion battery separator according to any one of the preceding embodiments, wherein the coating liquid is coated on one side or both sides of the base film, and then subjected to a shaping drying to obtain the lithium ion battery separator.

[0028] The present application has the following advantages:

[0029] The thienyl polyamide has strong hydrogen bonding effect, high molecular weight and regularity, which endows the material with excellent mechanical strength, high modulus and heat resistance. Moreover, the polarity of the amide group makes the material have good compatibility with electrolyte, and thus the separator has good wettability. The coating liquid of the present application contains thienyl polyamide nanofibers, which have large specific surface area and can promote electrolyte absorption and improve the compatibility of the separator with electrolyte. After coating, a uniform coating layer is formed, which is firmly bonded to the base film and has excellent wettability and thermal stability, thereby improving the safety of lithium batteries. In addition, the preparation of the coating liquid only requires mixing raw materials, and the process is green, environmentally friendly and simple to operate. The water-based coating cost is lower than that of commercially available oil-based products, and is suitable for industrialization. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below. If the specific conditions are not specified in the embodiments, the conventional conditions or the conditions recommended by the manufacturer are used. If the reagents or instruments used are not specified by the manufacturer, they are all conventional products that can be purchased on the market.

[0031] The coating liquid comprises 2-25% of thienyl polyamide nanofiber, 15-70% of inorganic ceramic, 1-5% of adhesive, 0.5-5% of auxiliary agent and the rest of deionized water by mass percentage.

[0032] The thienyl polyamide can form strong hydrogen bond interaction between molecules due to the rigid benzene ring and the alternating arrangement of amide bonds in its molecular structure, and has high molecular weight and high molecular regularity, thereby endowing the material with excellent mechanical strength, high modulus and outstanding heat resistance. In addition, the amide group has strong polarity, and the material exhibits good compatibility with electrolyte, so that the separator has excellent wetting performance. By introducing nanofiber with excellent flexibility to composite ceramic coating, the toughness of the coating can be effectively improved, and the phenomenon of powder falling during pressure process due to the high hardness of ceramic material can be avoided.

[0033] The coating liquid used in the present application adds thienyl polyamide material with high mechanical strength and high heat resistance. Thienyl polyamide nanofiber is particularly selected, which has a large specific surface area that can significantly increase the contact area with electrolyte, thereby more effectively promoting the absorption of electrolyte. This property can further improve the compatibility between the separator of the lithium ion battery using the coating liquid and the electrolyte.

[0034] In addition, the coating liquid provided by the present application can form a uniform coating after coating, and the coating has firm bonding performance with the base film. The coating has excellent wettability and thermal stability, which will significantly improve the safety performance of the lithium ion battery using the separator. At the same time, the coating liquid of the present application only needs to mix the raw materials, and the preparation process is green and environmentally friendly, simple to operate, and the cost of water-based coating is lower than that of the commercially available oil-based coated separator products, which is suitable for industrialization.

[0035] In an optional embodiment, the adhesive comprises a polymer A obtained by self-polymerization of the monomer of formula I, and the mass fraction of the polymer A in the coating liquid is 1%-5%; wherein the structure of the monomer of formula I is as follows:

[0036]

[0037] wherein R is one of linear or branched alkylene, cyclic alkylene, arylene and aralkylene, and X and Y are chain segments connecting ether oxygen and double bond.

[0038] The polymer A is selected as the adhesive, which is more conducive to improving the performance of the lithium battery separator using the coating liquid in cooperation with the thienyl polyamide nanofiber.

[0039] In an alternative embodiment, the monomer of formula I is obtained by reacting isocyanate with at least one of unsaturated hydroxyl compounds selected from N,N"-bis(2-hydroxyethyl)-N"-acryloyl-1,3-diaminopropane, N-(2,3-dihydroxypropyl)-2-propenamide, propenol, 3-buten-1-ol and N-trishydroxymethyl acrylamide in the presence of a catalyst.

[0040] In an alternative embodiment, the catalyst is at least one of butyl tin laurate and dimethyl tin acid ester.

[0041] And / or, the reaction temperature is 70-90℃, and the reaction time is 3 hours.

[0042] In an alternative embodiment, the polymer A is obtained by polymerization of the monomer of formula I in the presence of an initiator, the polymerization temperature is 75-85℃, the polymerization time is 4.5-5.5 hours, and the initiator is azobisisobutyronitrile.

[0043] Specifically, in some embodiments, the method for preparing the polymer A comprises: introducing nitrogen into a reaction bottle, adding isocyanate into the reaction bottle, stirring, adding unsaturated hydroxyl compounds, the molar ratio of the isocyanate and the unsaturated hydroxyl compounds being 1:2, then adding a catalyst of butyl tin laurate or dimethyl tin acid ester, the amount of the catalyst being 0.1%-1% of the total moles of the isocyanate and the unsaturated hydroxyl compounds, heating to 70-90℃ for 3 hours, cooling to room temperature, obtaining a reaction solution containing the monomer of formula I (urethane-containing diene), adding an initiator of azobisisobutyronitrile, the amount of the initiator being 0.1%-1% of the total moles of the isocyanate and the unsaturated hydroxyl compounds, and reacting at 80℃ for 5 hours to obtain the polymer A.

[0044] In an alternative embodiment, the adhesive further comprises at least one of polyacrylic polymer, polyvinyl alcohol, polyurethane polymer and polyimide.

[0045] And / or, the thienyl polyamide nanofiber has a diameter of 20-500 nanometers and a length of 0.5-50 micrometers, and has a higher specific surface area.

[0046] And / or, the thienyl polyamide nanofiber is selected from at least one of a polymer of 2,5-thiophenedicarboxylic dichloride and m-phenylenediamine, a polymer of 2,5-thiophenedicarboxylic dichloride and 4,4-diaminodiphenyl ether, a polymer of 2,5-thiophenedicarboxylic dichloride and m-phthaloyl dichloride and 4,4-diaminodiphenyl ether, a polymer of 2,5-thiophenedicarboxylic dichloride and m-phthaloyl dichloride and 4,4"-(1,4-phenylenedioxy)bisphenylamine, and a polymer of 2,5-thiophenedicarboxylic dichloride and 4,4-diaminodiphenyl ether and 2-(4-aminophenyl)-5-aminobenzimidazole;

[0047] And / or, the preparation method of the thienyl polyamide nanofiber comprises: electrospinning a spinning dope solution comprising an organic solvent, a thienyl polyamide, polyvinyl alcohol and lithium chloride to obtain the nanometer thienyl polyamide.

[0048] And / or, the inorganic carbon ceramic is selected from at least one of alumina, boehmite, silica, zirconia and zinc oxide.

[0049] And / or, the auxiliary agent is selected from at least one of an alcohol compound, a carbonate compound and sodium alkyl sulfonate.

[0050] In an optional embodiment, the inorganic carbon ceramic is selected from at least one of alumina and boehmite.

[0051] And / or, the auxiliary agent is selected from at least one of ethylene glycol, polyethylene glycol and dimethyl carbonate.

[0052] And / or, the electrospinning step comprises: a voltage of 6-10 kV, an extrusion rate of 2-2.2 mL / h, a stretching air pressure of 0.02-0.055 MPa, a spinneret inner diameter of 0.1-0.3 mm, and a receiving distance of 15-20 cm.

[0053] And / or, the spinning dope solution comprises N,N-dimethylformamide 500-900 g / kg, thienyl polyamide 50-100 g / kg, polyvinyl alcohol 10-50 g / kg and lithium chloride 10-50 g / kg.

[0054] The present application also provides a lithium ion battery separator, comprising a base film and a coating layer formed on one side or both sides of the base film, wherein the coating layer is obtained by drying the coating liquid according to any one of the preceding embodiments.

[0055] In an optional embodiment, the base film is selected from one of a PP base film, a PE base film and a PET base film.

[0056] The application also provides a preparation method of the lithium ion battery separator of any one of the preceding embodiments. The coating liquid is coated on one side or both sides of the base film, and then shaped and dried to obtain the lithium ion battery separator.

[0057] The features and performances of the application are further described in detail below in combination with examples.

[0058] Example 1

[0059] The application provides a preparation method of a lithium ion battery separator, which specifically comprises the following steps:

[0060] The reaction kettle is added with 50 g of water, 10 g of thienyl polyamide nanofiber, 20 g of aluminum oxide, 1 g of polymer A, and 1 g of polyethylene glycol, which are dispersed quickly under rapid stirring at a stirring speed of 150 rpm to obtain a coating liquid. The coating liquid is coated on both sides of a PE base film with a thickness of 7 microns, and the coating thickness of each side is 1 micron. The coating liquid is shaped and dried at 65°C to obtain a lithium ion battery separator. The preparation method of the polymer A comprises the following steps: nitrogen protection is performed on the reaction bottle, 0.1 mol of isophorone diisocyanate is added into the reaction bottle, stirring is performed, 0.2 mol of propylene glycol is added, then 0.0015 mol of butyl tin laurate is added, the temperature is increased to 70-90°C, and reaction is performed for 3 hours. The reaction liquid containing the monomer (dual olefin containing urethane) described in Formula I is obtained after cooling to room temperature. 0.0015 mol of initiator azobisisobutyronitrile is added, and reaction is performed at 80°C for 5 hours to obtain the polymer A.

[0061] The diameter of the thienyl polyamide nanofiber is 100 nm, and the length is 10 microns. The preparation method comprises the following steps: electrospinning is performed on a spinning dope solution comprising N,N-dimethylformamide, thienyl polyamide, polyvinyl alcohol, and lithium chloride to obtain the nanometer thienyl polyamide. The spinning dope solution comprises 700 g / L of organic solvent, 80 g / L of thienyl polyamide, 30 g / L of polyvinyl alcohol, and 30 g / L of lithium chloride. The conditions of the electrospinning step comprise the following: the voltage is 8 kV, the extrusion rate is 2.1 mL / h, the drawing air pressure is 0.04 MPa, the inner diameter of the spinneret is 0.2 mm, and the receiving distance is 18 cm.

[0062] In this embodiment, the thienyl polyamide is a polymer of 2,5-thiophene dicarboxylic acid chloride and m-phenylenediamine.

[0063] Example 2

[0064] The difference between this embodiment and Example 1 is that the thienyl polyamide is a polymer of 2,5-thiophene dicarboxylic acid chloride and 4,4-diamino diphenyl ether.

[0065] Example 3

[0066] The main difference between this example and Example 1 is that the thienyl polyamide is a polymer of 2,5-thiophenedicarboxylic dichloride and isophthaloyl dichloride with 4,4'-diaminodiphenyl ether, wherein the molar ratio of 2,5-thiophenedicarboxylic dichloride and isophthaloyl dichloride is 1 : 1.

[0067] Example 4

[0068] The main difference between this example and Example 1 is that the thienyl polyamide is a polymer of 2,5-thiophenedicarboxylic dichloride and isophthaloyl dichloride with 4,4'-(l,4-phenylenedioxy)bisbenzeneamine, wherein the molar ratio of 2,5-thiophenedicarboxylic dichloride and isophthaloyl dichloride is 1 : 1.

[0069] Example 5

[0070] The main difference between this example and Example 1 is that the thienyl polyamide is a polymer of 2,5-thiophenedicarboxylic dichloride and 4,4-diaminodiphenyl ether with 2-(4-aminophenyl)-5-aminobenzimidazole, wherein the molar ratio of 4,4-diaminodiphenyl ether and 2-(4-aminophenyl)-5-aminobenzimidazole is 1 : 1.

[0071] Example 6

[0072] The main difference between this example and Example 1 is that the polymer A is replaced by polyacrylic acid.

[0073] Example 7

[0074] The main difference between this example and Example 1 is that the composition of the coating solution is different; the coating solution comprises 25 grams of the thienyl polyamide fiber used in Example 1, 15 grams of boehmite, 5 grams of the polymer A used in Example 1, 0.5 grams of dimethyl carbonate, and 54.5 grams of deionized water.

[0075] Example 8

[0076] The main difference between this example and Example 1 is that the composition of the coating solution is different; the coating solution comprises 2 grams of the thienyl polyamide fiber used in Example 1, 70 grams of alumina, 1 gram of the polymer A used in Example 1, 5 grams of ethylene glycol, and 22 grams of deionized water.

[0077] Comparative Example 1

[0078] The main difference between this comparative example and Example 1 is that no thienyl polyamide is added to the coating solution.

[0079] Comparative Example 2

[0080] The main difference between this comparative example and Example 1 is that the thienyl polyamide in the coating solution is replaced by PET fiber.

[0081] Comparative Example 3

[0082] The main difference between the present comparative example and Comparative Example 2 is that the polymer A in the coating liquid is replaced by polyacrylic acid.

[0083] Comparative Example 4

[0084] The main difference between the present comparative example and Example 1 is that the thienyl polyamide nanofiber in the coating liquid is replaced by thienyl polyamide nanoparticles, and the particle size is equal to the fiber diameter in Example 1.

[0085] The performance of the lithium ion battery separator prepared in each of the above examples and comparative examples was tested, and the test results are shown in Table 1.

[0086] Among them, the test method and conditions of each performance are as follows:

[0087] (1) Thermal shrinkage test method:

[0088] The lithium battery separator prepared in each of the above examples and comparative examples was cut into a 10 cm x 10 cm size sample, and the longitudinal length (MD1) and transverse length (TD1) before heating were measured. The separator sample was placed in a vacuum oven at a temperature of 150°C for 1h, taken out, cooled to room temperature, and the longitudinal length (MD2) and transverse length (TD2) were measured again. The thermal shrinkage y was calculated according to the following formula.

[0089] Y(MD) = (MD1-MD2) / MD1 x 100%;

[0090] Y(TD) = (TD1-TD2) / TD1 x 100%.

[0091] (2) Peeling strength method: refer to the standard test of GB / T 36363-2018.

[0092] (3) Liquid absorption and retention rate test method: refer to the standard test of QB / T 2303.11-2008.

[0093] Table 1. Performance of lithium battery separator of examples and comparative examples

[0094]

[0095] The results in Table 1 show that the lithium ion battery separator prepared in the examples of the present application has good thermal stability and liquid absorption and retention rate, and low cost and small environmental pollution. In summary, the lithium ion battery separator provided by the present application has excellent performance and greatly improved safety performance, and has broad application prospect and great commercial value in the field of lithium batteries.

[0096] The above merely provides the preferred embodiments of the present application, and is not used to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the principles and technical scope of the present application shall fall into the scope of the present application.

Claims

1. A coating liquid characterized by comprising, The thiofene polyamide nanofiber, the inorganic ceramic, the adhesive, the additive and the deionized water are 2-25%, 15-70%, 1-5%, 0.5-5% and the balance respectively by mass percentage.

2. The coating fluid of claim 1, wherein The adhesive comprises a polymer A obtained by self-polymerization of a monomer of formula I, and the mass fraction of the polymer A in the coating liquid is 1%-5%; wherein, the structure of the monomer of formula I is as follows: R is one of linear or branched alkylene, cyclic alkylene, arylene and aralkylene, and X and Y are chain segments connecting ether oxygen and double bond.

3. The coating fluid of claim 2, wherein The monomer of formula I is obtained by reacting isocyanate with at least one of unsaturated hydroxyl compounds selected from N, N'-bis(2-hydroxyethyl)-N'-acryloyl-1,3-diaminopropane, N-(2,3-dihydroxypropyl)-2-propenamide, propenol, 3-butene-1-ol and N-trihydroxymethyl acrylamide in the presence of a catalyst.

4. The coating fluid of claim 3, wherein The catalyst is at least one of butyl tin laurate and dimethyl tin acid ester; The reaction temperature is 70-90 DEG C, and the reaction time is 3 hours.

5. The coating fluid of claim 2, wherein The polymer A is obtained by polymerization of the monomer of formula I under the action of an initiator, the polymerization temperature is 75-85 DEG C, the polymerization time is 4.5-5.5 hours, and the initiator is azobisisobutyronitrile.

6. The coating fluid of claim 1, wherein The adhesive further comprises at least one of polyacrylic polymer, polyvinyl alcohol, polyurethane polymer and polyimide; The diameter of the thiofene polyamide nanofiber is 20-500 nanometers, and the length is 0.5-50 microns; The thiofene polyamide nanofiber is at least one of a polymer of 2,5-thiophene dicarboxylic chloride and m-phenylenediamine, a polymer of 2,5-thiophene dicarboxylic chloride and 4,4-diamino diphenyl ether, a polymer of 2,5-thiophene dicarboxylic chloride and m-phthaloyl chloride and 4,4-diamino diphenyl ether, a polymer of 2,5-thiophene dicarboxylic chloride and m-phthaloyl chloride and 4,4'-(1,4-benzenedioxy) bisphenylamine, and a polymer of 2,5-thiophene dicarboxylic chloride and 4,4-diamino diphenyl ether and 2-(4-aminophenyl)-5-aminobenzimidazole; The preparation method of the thiofene polyamide nanofiber comprises electrospinning a spinning dope comprising an organic solvent, thiofene polyamide, polyvinyl alcohol and lithium chloride to obtain the nanometer thiofene polyamide; The inorganic ceramic is at least one of alumina, boehmite, silica, zirconia and zinc oxide; The additive is at least one of alcohol compound, carbonate compound and sodium alkyl sulfonate.

7. The coating fluid of claim 6, wherein The inorganic ceramic is at least one of alumina and boehmite; The additive is at least one of ethylene glycol, polyethylene glycol and dimethyl carbonate; The conditions of the electrospinning step comprise a voltage of 6-10 kV, an extrusion rate of 2-2.2 mL / h, a stretching air pressure of 0.02-0.055 MPa, a spinneret inner diameter of 0.1-0.3 mm and a receiving distance of 15-20 cm. And / or, the spinning dope comprises N,N-dimethylformamide 500-900 g / kg, thiophene polyamide 50-100 g / kg, polyvinyl alcohol 10-50 g / kg and lithium chloride 10-50 g / kg.

8. A lithium-ion battery separator, characterized by, The base film is selected from one of PP base film, PE base film and PET base film.

9. The lithium-ion battery separator of claim 8, wherein, The base film is selected from one of PP base film, PE base film and PET base film.

10. A method of producing the lithium-ion battery separator according to claim 8 or 9, characterized in that, The coating liquid is coated on one side or both sides of the base film, followed by shaping and drying to obtain the lithium ion battery separator.

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