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CN-121991556-A - Preparation method and application of high-cohesiveness conductive coating slurry

CN121991556ACN 121991556 ACN121991556 ACN 121991556ACN-121991556-A

Abstract

The invention relates to the technical field of battery materials, and discloses a preparation method and application of high-cohesiveness conductive coating slurry. The conductive coating slurry comprises, by weight, 20-30 parts of PVDF resin, 5-10 parts of modified polyacrylic acid, 8-12 parts of reinforcing filler, 30-50 parts of deionized water, 1-3 parts of defoamer and 2-4 parts of dispersing agent, wherein the slurry adopts PVDF resin as matrix resin, and modified polyacrylic acid and reinforcing filler are added, so that the adhesive property of the slurry is improved, and the phenomena of falling, stripping and the like caused by poor adhesive property are reduced.

Inventors

  • CAO ZHE
  • Wei Guiyong

Assignees

  • 宇锵新材料(湖北)有限公司

Dates

Publication Date
20260508
Application Date
20241106

Claims (9)

  1. 1. The preparation method of the high-cohesiveness conductive coating slurry is characterized by comprising the following raw materials, by weight, 20-30 parts of PVDF resin, 5-10 parts of modified polyacrylic acid, 8-12 parts of reinforcing filler, 30-50 parts of deionized water, 1-3 parts of a defoaming agent and 2-4 parts of a dispersing agent; The preparation method comprises the following steps of weighing raw materials according to parts by weight, adding reinforcing filler and dispersing agent into deionized water, performing ultrasonic dispersion for 10-20min, adding PVDF resin, modified polyacrylic acid and defoaming agent, and continuously stirring for 30-50min to obtain high-cohesiveness conductive coating slurry; The modified polyacrylic acid is prepared by the following steps: Step A1, adding melamine, acrylic acid, 1-hydroxybenzotriazole and 1- (3-dimethylaminopropyl) -3-ethylcarbodiimide hydrochloride into methylene dichloride, uniformly dispersing, and stirring for reacting for 1-2h to obtain an intermediate product; Step A2, adding cyanoacetic acid into an intermediate product, stirring for 30min, adding 1-hydroxybenzotriazole and 1- (3-dimethylaminopropyl) -3-ethylcarbodiimide hydrochloride, continuously stirring for reacting for 2-3h, adding saturated K 2 CO 3 aqueous solution, washing for three times, and drying by using anhydrous Na 2 SO 4 to obtain a functional monomer; And A3, dispersing the emulsifier in deionized water uniformly, adding acrylic acid, methyl methacrylate, butyl acrylate and functional monomers, stirring for 30min to form a pre-emulsion, adding ammonium persulfate into the deionized water, stirring for 10min at 65-75 ℃, slowly dropwise adding the pre-emulsion, dropwise adding the pre-emulsion within 1-2h, heating to 80-90 ℃ for continuous reaction for 2-3h, and filtering to obtain the modified polyacrylic acid.
  2. 2. The method for preparing a highly adhesive conductive coating paste according to claim 1, wherein the amount ratio of melamine, acrylic acid, 1-hydroxybenzotriazole, 1- (3-dimethylaminopropyl) -3-ethylcarbodiimide hydrochloride and methylene chloride in step A1 is 0.01-0.03mol:0.01-0.03mol:0.011-0.033 mol:200mL.
  3. 3. The method for preparing a highly adhesive conductive coating paste according to claim 1, wherein the molar ratio of cyanoacetic acid in step A2 to melamine in step A1 is 2:1, and the molar ratio of cyanoacetic acid, 1-hydroxybenzotriazole and 1- (3-dimethylaminopropyl) -3-ethylcarbodiimide hydrochloride is 1:1:1.
  4. 4. The method for preparing the high-adhesion conductive coating slurry according to claim 1, wherein in the step A3, the mass ratio of ammonium persulfate to deionized water to the pre-emulsion is 0.03-0.1:50-80:63-109, and the mass ratio of emulsifier to deionized water to acrylic acid to methyl methacrylate to butyl acrylate to the functional monomer is 1-2:50-80:3-9:7-12:1-3:1-3.
  5. 5. The method of preparing a highly adhesive conductive coating paste according to claim 1, wherein the reinforcing filler is prepared by the steps of: step B1, mixing and stirring 4mol/L nitric acid and 10mol/L sulfuric acid uniformly, adding the carbon nano tube, stirring at room temperature for 12-18h, filtering, washing and drying to obtain carboxylated carbon nano tube; Step B2, adding 2-amino terephthalic acid and nickel nitrate hexahydrate into a mixed solution of DMF, deionized water and ethanol in a volume ratio of 1:1:1, stirring for 30min, slowly dripping 0.4mol/L sodium hydroxide solution, stirring for 10-20min, transferring into an autoclave, reacting for 6-8h at 120 ℃, centrifuging, washing, drying, and then placing into a muffle furnace at 350-450 ℃ for high-temperature calcination for 2-3h to obtain the carbon nano tube/Ni-MOF composite material; And B3, uniformly dispersing chitosan in a 3wt% sodium hydroxide solution, refrigerating for 24 hours at the temperature of minus 10 ℃, thawing, centrifuging, drying and re-dispersing in deionized water to obtain a chitosan solution, adding the carbon nano tube/Ni-MOF composite material into a 2wt% glutaraldehyde solution for dispersing, heating to the temperature of 45 ℃ for reacting for 30 minutes, centrifuging, washing, adding the chitosan solution, maintaining the temperature for reacting for 2-4 hours, centrifuging, washing and drying to obtain the reinforcing filler.
  6. 6. The method of claim 5, wherein the ratio of nitric acid, sulfuric acid and carbon nanotubes used in step B1 is 5 mL/15 mL/0.1-0.5 g.
  7. 7. The method for preparing a highly adhesive conductive coating paste according to claim 5, wherein the dosage ratio of 2-amino terephthalic acid, nickel nitrate hexahydrate, mixed solution and sodium hydroxide solution in step B2 is 0.4-1.2g:0.5-1.5g:150ml:10ml.
  8. 8. The method for preparing a highly adhesive conductive coating paste according to claim 5, wherein the dosage ratio of the carbon nanotube/Ni-MOF composite material, glutaraldehyde solution and chitosan solution in step B3 is 1g:20-40ml:10ml, and the dosage ratio of chitosan, sodium hydroxide solution and deionized water in the chitosan solution is 1-5g:20ml:10ml.
  9. 9. Use of the high-cohesiveness conductive coating slurry prepared by the preparation method according to any one of claims 1-8 in carbon-coated aluminum foil of lithium batteries.

Description

Preparation method and application of high-cohesiveness conductive coating slurry Technical Field The invention relates to the technical field of battery materials, in particular to a preparation method and application of high-cohesiveness conductive coating slurry. Background The diaphragm in lithium ion battery is an essential key material of electrode, it not only prevents the positive and negative poles of battery from direct contact to cause short circuit, but also allows lithium ion to be transmitted through its microporous structure to form charge-discharge loop, and when overcharging or temperature rise, the diaphragm also has high temperature self-closing property to block current conduction to prevent explosion, therefore, the performance of diaphragm directly affects the electrical property and safety performance of battery. At present, the most commonly used binder in the lithium ion battery industry is polyvinylidene fluoride (PVDF), and the binder has the advantages of strong oxidation and reduction resistance, good thermal stability, easy dispersion and the like. The binding force of the carbon-coated aluminum foil after gluing is greatly related to the using amount of PVDF resin, and the required binding force can be achieved through the large coating amount, but the thickness of the carbon-coated aluminum foil is overlarge due to the increase of the PVDF coating amount, so that the overall performance of the battery is affected, such as reduction of multiplying power and reduction of cycle performance. Therefore, researchers are required to develop a slurry with a small coating amount and good adhesive properties to meet the actual production demands. Disclosure of Invention In order to solve the technical problems, the invention provides a preparation method and application of high-cohesiveness conductive coating slurry. The aim of the invention can be achieved by the following technical scheme: The high-cohesiveness conductive coating slurry comprises, by weight, 20-30 parts of PVDF resin, 5-10 parts of modified polyacrylic acid, 8-12 parts of reinforcing filler, 30-50 parts of deionized water, 1-3 parts of defoamer and 2-4 parts of dispersing agent; The preparation method comprises the following steps: Weighing raw materials according to parts by weight, adding reinforcing filler and dispersing agent into deionized water, performing ultrasonic dispersion for 10-20min, adding PVDF resin, modified polyacrylic acid and defoaming agent, and continuously stirring for 30-50min to obtain high-cohesiveness conductive coating slurry; The modified polyacrylic acid is prepared by the following steps: Step A1, adding melamine, acrylic acid, 1-hydroxybenzotriazole and 1- (3-dimethylaminopropyl) -3-ethylcarbodiimide hydrochloride into methylene dichloride, uniformly dispersing, and stirring for reacting for 1-2h to obtain an intermediate product; Step A2, adding cyanoacetic acid into an intermediate product, stirring for 30min, adding 1-hydroxybenzotriazole and 1- (3-dimethylaminopropyl) -3-ethylcarbodiimide hydrochloride, continuously stirring for reacting for 2-3h, adding saturated K 2CO3 aqueous solution, washing for three times, and drying by using anhydrous Na 2SO4 to obtain a functional monomer; Step A3, dispersing an emulsifier in deionized water uniformly, adding acrylic acid, methyl methacrylate, butyl acrylate and a functional monomer, stirring for 30min to form a pre-emulsion, adding ammonium persulfate into the deionized water, stirring for 10min at 65-75 ℃, slowly dropwise adding the pre-emulsion, dropwise adding the pre-emulsion within 1-2h, heating to 80-90 ℃ for continuous reaction for 2-3h, and filtering to obtain modified polyacrylic acid; Further, in the step A1, the dosage ratio of melamine, acrylic acid, 1-hydroxybenzotriazole, 1- (3-dimethylaminopropyl) -3-ethylcarbodiimide hydrochloride and methylene dichloride is 0.01-0.03 mol:0.01-0.03 mol:0.011-0.033 mol:200 mL; further, the molar ratio of cyanoacetic acid in step A2 to melamine in step A1 is 2:1, and the molar ratio of cyanoacetic acid, 1-hydroxybenzotriazole, and 1- (3-dimethylaminopropyl) -3-ethylcarbodiimide hydrochloride is 1:1:1; further, in the step A3, the mass ratio of ammonium persulfate to deionized water to the pre-emulsion is 0.03-0.1:50-80:63-109, and the mass ratio of the emulsifier to deionized water to the acrylic acid to the methyl methacrylate to the butyl acrylate to the functional monomer in the pre-emulsion is 1-2:50-80:3-9:7-12:1-3:1-3. The reinforcing filler is prepared by the following steps: step B1, mixing and stirring 4mol/L nitric acid and 10mol/L sulfuric acid uniformly, adding the carbon nano tube, stirring at room temperature for 12-18h, filtering, washing and drying to obtain carboxylated carbon nano tube; Step B2, adding 2-amino terephthalic acid and nickel nitrate hexahydrate into a mixed solution of DMF, deionized water and ethanol in a volume ratio of 1:1:1, stirring for 30min, slowly drip