Polymer films, methods for producing the same, and their use

Abstract

This application provides a polymer film, a method for producing the same, and its use. The polymer film comprises, by mass percentage, 90-99.9% of a host polymer and 0.1-10% of a magnetic material-polymer modified carbon nanocomposite. In this application, the use of a magnetic material-polymer modified carbon nanocomposite improves the thermal conductivity of the polymer film, particularly the thermal conductivity in the thickness direction of the polymer film. A composite current collector manufactured using the polymer film according to this application as a base film has good conductivity and a low void defect rate.

Claims

1. A polymer film comprising, by mass percentage, 90 to 99.9% of a host polymer and 0.1 to 10% of a magnetic material-polymer-modified carbon nanocomposite material, The raw materials for preparing the magnetic material-polymer-modified carbon nanocomposite include a carbon nanomaterial and a magnetic material precursor. The mass ratio of the carbon nanomaterial, polymer, and magnetic material precursor is (2-5):(70-200):(40-85), The magnetic material precursor comprises one or at least two of the following: an iron source, a neodymium source, a boron source, an aluminum source, a nickel source, a cobalt source, a chromium source, and a samarium source. The aforementioned magnetic material-polymer-modified carbon nanocomposite material is Step (S1) of preparing carbon oxide nanomaterials, Step (S2) involves uniformly mixing carbon oxide nanomaterial and solvent A, then adding a weakly alkaline substance and a magnetic material precursor, uniformly mixing them, and then reacting them to obtain a carbon nanomaterial modified with magnetic material. The material is prepared by a method comprising the step (S3) of dispersing a magnetic material-modified carbon nanomaterial in solvent B, oxidizing it, adding a polymer, and reacting it to obtain the magnetic material-polymer-modified carbon nanocomposite material. The solvent A includes an alcohol solvent, The solvent B is one or at least two selected from water, diethyl ether, or ethanol. A polymer film wherein the weakly alkaline substance described in step (S2) includes one or at least two of the following: sodium acrylate, sodium acetate, sodium citrate, sodium tartrate, or sodium benzoate.

2. The polymer film according to claim 1, wherein the polymer in the magnetic material-polymer-modified carbon nanocomposite material is one or at least two selected from polyvinyl alcohol, polyethylene glycol, polyacrylic acid, or polysiloxane.

3. The polymer film according to claim 1 or 2, wherein the carbon nanomaterial in the magnetic material-polymer-modified carbon nanocomposite material is one or at least two selected from graphene, carbon nanotubes, carbon nanofibers, or nanodiamonds.

4. The polymer film according to any one of claims 1 to 3, wherein the magnetic material in the magnetic material-polymer modified carbon nanocomposite material is one or at least two selected from triiron tetroxide, diiron trioxide, neodymium iron boron, aluminum nickel cobalt, iron chromium cobalt, or samarium cobalt.

5. The polymer film according to any one of claims 1 to 4, wherein the host polymer is one or at least two selected from polypropylene, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyethylene, ethylene propylene copolymer, polyvinyl chloride, polyvinylidene fluoride, polytetrafluoroethylene, polyphenylene sulfide, polyphenylene oxide, polystyrene, or polyimide.

6. The polymer film according to any one of claims 1 to 5, wherein the thickness of the polymer film is 1 μm or more.

7. A method for producing a polymer film according to any one of claims 1 to 6, The aforementioned manufacturing method is Step (1) involves mixing a host polymer and a magnetic material-polymer-modified carbon nanocomposite material, followed by melting, filtering, and extruding to obtain a molten material. Step (2) includes casting the molten material obtained in step (1) onto a cast roll, cooling and molding it, and then performing longitudinal stretching, transverse stretching, and heat treatment to obtain the polymer film. Both step (1) and step (2) are performed in the presence of a magnetic field. A manufacturing method wherein the direction of the magnetic field is parallel to the thickness direction of the polymer film.

8. The manufacturing method according to claim 7, wherein the magnetic field strength is 0.1 to 2.0 T.

9. A composite current collector comprising a metal layer and a polymer film layer which is a polymer film according to any one of claims 1 to 6.

10. A battery comprising the composite current collector described in claim 9.

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