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CN-121983751-A - Composite spot-coating slurry, and preparation method and application thereof

CN121983751ACN 121983751 ACN121983751 ACN 121983751ACN-121983751-A

Abstract

The invention discloses a composite spot-coating slurry, a preparation method and application thereof, wherein a composite spot-coating film comprises a base film and a coating layer on the base film, the coating layer is coated by the composite spot-coating slurry, the preparation method of the composite spot-coating slurry comprises the steps of mixing ceramic slurry and organic slurry until the ceramic slurry and the organic slurry are uniform, and the composite spot-coating slurry is obtained, wherein the ceramic slurry comprises ceramic materials, the organic slurry comprises organic materials, the ceramic materials comprise a first dispersing agent, ceramic powder, a wetting agent, a first thickening agent and a first binding agent, and the organic materials comprise a second dispersing agent, an organic polymer, a second thickening agent and a second binding agent. The composite spot coating slurry and the spot coating spot matrix cooperatively reduce the risk of blocking holes by particles, improve the air permeability of the diaphragm and reduce the internal resistance of the lithium battery.

Inventors

  • ZHAO YUANXIANG
  • YUAN HAICHAO
  • XU FENG
  • XING PENG
  • Su bihai
  • TIAN HAILONG
  • Yang Zhentu

Assignees

  • 河北金力新能源科技有限公司

Dates

Publication Date
20260505
Application Date
20260121

Claims (10)

  1. 1. A composite spot coating film is characterized by comprising a base film and a coating layer on the base film, wherein the coating layer is coated by composite spot coating slurry, and the method for preparing the composite spot coating slurry comprises the steps of mixing ceramic slurry and organic slurry until the ceramic slurry and the organic slurry are uniform to obtain the composite spot coating slurry, wherein the ceramic slurry comprises a ceramic material and first water, the organic slurry comprises an organic material and second water, and the ratio of the ceramic material to the organic material in the ceramic slurry is (0.1-20) 1; The ceramic material comprises a first dispersing agent, ceramic powder, a wetting agent, a first thickening agent and a first binder, and the organic material comprises a second dispersing agent, an organic polymer, a second thickening agent and a second binder.
  2. 2. The composite spot coating film according to claim 1, wherein the ceramic slurry has a solid content of 25 to 36wt% and the organic slurry has a solid content of 15 to 20 wt%.
  3. 3. The composite spot coating film according to claim 1, wherein the ratio of the first dispersant, the ceramic powder, the wetting agent, the first thickener and the first binder in the ceramic material is (0.4-0.8): (28-36): (2-8): (5-9): (1-5) in parts by mass.
  4. 4. The composite spot-coating film according to claim 1, wherein the ratio of the second dispersant, the organic polymer, the second thickener and the second binder in the organic material is (0.1 to 0.5): (17 to 20): (8 to 12): (7 to 11) in parts by mass.
  5. 5. The composite spot coating film according to claim 1, wherein the organic polymer is one or a mixture of several of polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyvinylidene fluoride-trifluoroethylene copolymer, polyvinylidene fluoride-chlorotrifluoroethylene copolymer, tetrafluoroethylene-vinylidene fluoride copolymer and polymethyl methacrylate.
  6. 6. The composite spot coating film according to claim 1, wherein the ceramic powder is one or a mixture of several of alumina, boehmite, silica, titania, calcium oxide, calcium carbonate, calcium titanate and barium titanate.
  7. 7. The composite spot coating according to claim 1, wherein the viscosity of the ceramic slurry is 35 to 95mpa·s.
  8. 8. The composite spot coating film according to claim 1, wherein the viscosity of the organic slurry is 100 to 500mpa·s.
  9. 9. The method for preparing the composite spot coating film according to any one of claims 1 to 8, which is characterized by comprising the steps of coating the composite spot coating slurry on a base film in a spot coating mode, drying, and obtaining a coating on the base film to obtain the composite spot coating film.
  10. 10. The use of the composite spot coating according to claim 1 for improving the safety and electrochemical properties of lithium batteries.

Description

Composite spot-coating slurry, and preparation method and application thereof Technical Field The invention belongs to the technical field of battery diaphragms, and particularly relates to a composite spot-coating slurry, a preparation method and application thereof. Background Lithium Ion Batteries (LIBs) have the characteristics of high voltage, high specific energy, high cycle efficiency and the like, and are widely used in various fields of production and life, wherein the diaphragm is an indispensable part of the lithium ion battery and plays an important role in the safety and electrochemical performance of the lithium ion battery. Wettability, heat resistance and adhesiveness are important parameters for evaluating a separator of a lithium ion battery, for example, the invention patent of publication No. CN109065805A improves separator wettability by a method of preparing a high-liquid-absorption polymer coating, but adopts low-crystallinity polymer powder, has no gain on mechanical properties and thermal stability of the separator, and the invention patent of publication No. CN111129405A uses a mixed coating separator slurry, which improves heat resistance of the separator but has poor interface effect, so that the capacity retention rate of the battery is dropped by 5% only by 100 cycles. Disclosure of Invention Aiming at the defects of the prior art, the invention aims to provide a composite dot coating film. Another object of the present invention is to provide a method for producing the above composite dot coating film. The aim of the invention is achieved by the following technical scheme. The composite spot coating comprises a base film and a coating on the base film, wherein the coating is coated by composite spot coating slurry, and the method for preparing the composite spot coating slurry comprises the steps of mixing ceramic slurry and organic slurry until the ceramic slurry and the organic slurry are uniform to obtain composite spot coating slurry, wherein the ceramic slurry comprises ceramic materials and first water, the organic slurry comprises organic materials and second water, and the ratio of the ceramic materials to the organic materials in the ceramic slurry is (0.1-20) 1; The ceramic material comprises a first dispersing agent, ceramic powder, a wetting agent, a first thickening agent and a first binder, and the organic material comprises a second dispersing agent, an organic polymer, a second thickening agent and a second binder. In the technical scheme, the solid content of the ceramic slurry is 25-36wt%, and the solid content of the organic slurry is 15-20wt%. In the technical scheme, in the ceramic material, the ratio of the first dispersing agent to the ceramic powder to the wetting agent to the first thickening agent to the first binder is (0.4-0.8) (28-36) (2-8) (5-9) (1-5). In the technical scheme, in the organic material, the ratio of the second dispersant to the organic polymer to the second thickener to the second binder is (0.1-0.5): 17-20): 8-12): 7-11. In the above technical solution, the first thickener is a cellulose thickener. In the above technical solution, the second thickener is a cellulose thickener. In the technical scheme, the cellulose thickener comprises one or a mixture of more of sodium carboxymethyl cellulose, carboxymethyl hydroxypropyl cellulose and hydroxyethyl cellulose. In the technical scheme, the first binder comprises polyacrylate. In the above technical solution, the second binder includes polyacrylic acid. In the above technical scheme, the organic polymer is one or a mixture of more than one of polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyvinylidene fluoride-trifluoroethylene copolymer, polyvinylidene fluoride-chlorotrifluoroethylene copolymer, tetrafluoroethylene-vinylidene fluoride copolymer and polymethyl methacrylate. In the technical scheme, the ceramic powder is one or a mixture of more of aluminum oxide, boehmite, silicon dioxide, titanium dioxide, calcium oxide, calcium carbonate, calcium titanate and barium titanate, and is preferably boehmite or aluminum oxide. In the above technical scheme, the first dispersing agent is one or a mixture of more of cationic ammonium salt dispersing agent, acrylic acid ester polymer dispersing agent, polyurethane polymer dispersing agent and polyester polymer dispersing agent. In the above technical scheme, the second dispersant is one or a mixture of more of cationic ammonium salt dispersant, acrylic polymer dispersant, polyurethane polymer dispersant and polyester polymer dispersant. In the technical scheme, the wetting agent is one or a mixture of a nonionic surfactant, an organosilicon nonionic surfactant and an anionic surfactant. In the technical scheme, the nonionic surfactant is polyoxyethylene octyl phenol ether or polyoxyethylene lauryl alcohol ether, the organosilicon nonionic surfactant is polyether modified dimethyl polysiloxane, and the anioni