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CN-122000624-A - Battery diaphragm, preparation method thereof and lithium ion battery

CN122000624ACN 122000624 ACN122000624 ACN 122000624ACN-122000624-A

Abstract

The invention relates to the technical field of lithium ion batteries, in particular to a battery diaphragm, a preparation method thereof and a lithium ion battery. The invention provides a battery separator, which comprises a base film and an oxidation-resistant and heat-resistant coating arranged on one side surface of the base film, wherein the oxidation-resistant and heat-resistant coating comprises a modified porous material and a heat-resistant inorganic material, and the modified porous material comprises a porous base material and a light stabilizer loaded on the porous base material. According to the battery diaphragm, the porous base material is used for loading the light stabilizer and is matched with the heat-resistant inorganic material, so that a coating is formed on the surface of the base film, the interface stability under high pressure is realized, and the energy density and the cycle performance of the lithium ion battery are improved.

Inventors

  • LIU QIZHOU
  • WANG XIAOMING
  • ZHU JITAO
  • YANG HAOTIAN
  • NIU XUHONG
  • LI NA

Assignees

  • 江苏卓高新材料科技有限公司

Dates

Publication Date
20260508
Application Date
20260210

Claims (10)

  1. 1. A battery separator, characterized by comprising a base film and an oxidation-resistant and heat-resistant coating layer arranged on one side surface of the base film; the anti-oxidation heat-resistant coating comprises a modified porous material and a heat-resistant inorganic material, wherein the modified porous material comprises a porous base material and a light stabilizer loaded on the porous base material.
  2. 2. The battery separator according to claim 1, comprising at least one of the following features (1) to (3); (1) In the modified porous material, the mass ratio of the porous base material to the light stabilizer is 4 (1-3); (2) The particle size D50 of the modified porous material is 1.5-5 mu m; (3) The specific surface area of the modified porous material is 20-55 m 2 /g.
  3. 3. The battery separator according to claim 1, comprising at least one of the following features (1) to (4); (1) The porous substrate comprises at least one of porous alumina, porous silica, metal organic framework material, covalent organic framework material, and zeolite; (2) The particle size D50 of the porous base material is 1.5-5 mu m; (3) The average pore diameter of the porous base material is 5-25 nm; (4) The specific surface area of the porous base material is 200-350 m 2 /g.
  4. 4. The battery separator of claim 1, wherein the light stabilizer comprises at least one of UV-3346, UV-3853, TH-944, tinuvin770, tinuvin144, and Sanduvor VSU; And/or the molecular weight of the light stabilizer is 1000-3000.
  5. 5. The battery separator according to claim 1, wherein the preparation method of the modified porous material comprises the steps of dissolving a light stabilizer in an organic solvent to obtain a mixed solution, uniformly mixing a porous base material and the mixed solution, and sequentially drying, grinding and sieving to obtain the modified porous material; Preferably, the solid content of the mixed solution is 5% -10%.
  6. 6. The battery separator of claim 1, wherein the heat resistant inorganic material comprises at least one of alumina, silica, silicon carbide, silicon nitride, magnesium silicate, magnesium hydroxide, barium carbonate, and boehmite; And/or the particle diameter D50 of the heat-resistant inorganic material is 0.4-1 mu m.
  7. 7. The battery separator according to claim 1, wherein a ratio of a particle diameter of the heat-resistant inorganic material to a particle diameter of the modified porous material is 1 (2.4 to 4); and/or the mass ratio of the heat-resistant inorganic material to the modified porous material is 1 (3-10).
  8. 8. The battery separator according to claim 1, comprising at least one of the following features (1) to (4); (1) The antioxidation and heat-resistant coating also comprises at least one of a binder, a dispersing agent and a wetting agent; (2) The water content of the antioxidant heat-resistant coating is 2000-10000 ppm; (3) The thickness of the antioxidation heat-resistant coating is 2-7 mu m; (4) The base film includes at least one of a polyethylene microporous film, a polypropylene microporous film, and a polyolefin multilayer composite microporous film.
  9. 9. The method for preparing the battery separator according to any one of claims 1 to 8, comprising the steps of: and coating the slurry containing the modified porous material and the heat-resistant inorganic material on one side surface of the base film, and drying to obtain the battery separator.
  10. 10. A lithium ion battery is characterized by comprising a positive electrode plate, the battery diaphragm and a negative electrode plate according to any one of claims 1-8, wherein the positive electrode plate is adjacent to an antioxidant heat-resistant coating of the battery diaphragm.

Description

Battery diaphragm, preparation method thereof and lithium ion battery Technical Field The invention relates to the technical field of lithium ion batteries, in particular to a battery diaphragm, a preparation method thereof and a lithium ion battery. Background The lithium ion battery has the unique advantages of high specific energy, high working voltage, long cycle life, no pollution, high safety performance and the like, and has been widely applied in a plurality of fields of portable electronic equipment, electric automobiles, energy storage systems and the like. To further increase the energy density of lithium ion batteries, the development and application of high voltage cathode materials is considered as a key technological path to break through the existing energy bottlenecks. The trend in future will continue to focus on the development of positive electrode materials with higher specific capacities and higher operating voltage platforms. However, in the process of realizing commercial application of a high-voltage system, the stability problem of the positive electrode/electrolyte interface under high voltage, especially the chemical degradation of the electrolyte under the high-potential condition, becomes a core challenge to be solved. Particularly, in the case of a layered oxide positive electrode material, active oxygen (e.g., singlet oxygen) and various radicals (e.g., CH 3、·OCH3、·OCOOCH3 and H 2 c=ch—o·or the like) are easily released from the surface of the positive electrode material under a high-voltage condition. These highly reactive species can continue to attack electrolyte components, initiating and accelerating electrolyte decomposition. This process not only results in electrolyte loss, but also causes rapid decay in battery capacity and reduced cycle life. In view of this, the present invention has been made. Disclosure of Invention A first object of the present invention is to provide a battery separator that solves the problem of interfacial stability under high pressure. A second object of the present invention is to provide a method for manufacturing a battery separator. A third object of the present invention is to provide a lithium ion battery. In order to achieve the above object of the present invention, the following technical solutions are specifically adopted: the invention provides a battery diaphragm, which comprises a base film and an antioxidation and heat-resistant coating arranged on one side surface of the base film; the anti-oxidation heat-resistant coating comprises a modified porous material and a heat-resistant inorganic material, wherein the modified porous material comprises a porous base material and a light stabilizer loaded on the porous base material. Further, at least one of the following features (1) to (3) is included; (1) In the modified porous material, the mass ratio of the porous base material to the light stabilizer is 4 (1-3); (2) The particle size D50 of the modified porous material is 1.5-5 mu m; (3) The specific surface area of the modified porous material is 20-55 m 2/g. Further, at least one of the following features (1) to (4) is included; (1) The porous substrate comprises at least one of porous alumina, porous silica, metal organic framework material, covalent organic framework material, and zeolite; (2) The particle size D50 of the porous base material is 1.5-5 mu m; (3) The average pore diameter of the porous base material is 5-25 nm; (4) The specific surface area of the porous base material is 200-350 m 2/g. Further, the light stabilizer comprises at least one of UV-3346, UV-3853, TH-944, tinuvin770, tinuvin144, and Sanduvor VSU; And/or the molecular weight of the light stabilizer is 1000-3000. The preparation method of the modified porous material comprises the steps of dissolving a light stabilizer in an organic solvent to obtain a mixed solution, uniformly mixing a porous base material and the mixed solution, and sequentially drying, grinding and sieving to obtain the modified porous material. Preferably, the solid content of the mixed solution is 5% -10%. Further, the heat-resistant inorganic material includes at least one of alumina, silica, silicon carbide, silicon nitride, magnesium silicate, magnesium hydroxide, barium carbonate, and boehmite; And/or the particle diameter D50 of the heat-resistant inorganic material is 0.4-1 mu m. Further, the ratio of the particle size of the heat-resistant inorganic material to the particle size of the modified porous material is 1 (2.4-4); and/or the mass ratio of the heat-resistant inorganic material to the modified porous material is 1 (3-10). Further, at least one of the following features (1) to (4) is included; (1) The antioxidation and heat-resistant coating also comprises at least one of a binder, a dispersing agent and a wetting agent; (2) The water content of the antioxidant heat-resistant coating is 2000-10000 ppm; (3) The thickness of the antioxidation heat-resistant coating is