A graphene composite current collector and preparation method thereof

Abstract

The invention discloses a graphene composite current collector and a preparation method thereof. The graphene composite current collector is a core-shell structure composite current collector composed of an electrically insulating core and a conductive shell. The conductive shell is coated on the outside of the electrically insulating core. The current collector has the characteristics of good structural stability, high strength, light weight, fast conductivity, good heat dissipation, high energy density and high safety. The preparation method of the graphene composite current collector has the characteristics of simple process, strong reliability and high production efficiency, and is particularly suitable for large-scale industrial production.

Description

Technical Field

[0001] The invention relates to a graphene composite current collector and a preparation method thereof, belonging to the technical field of batteries. Background Art

[0002] Existing composite current collectors are generally composed of three parts, two conductive layers and one insulating layer, and have a sandwich structure. For example, patent CN106910879A "A current collector, its pole piece and battery", and CN118263451A "Composite current collector with pole ears and its preparation method and application". This sandwich structure composite current collector has the following problems. First, the sandwich structure with an electrical insulating layer sandwiched between two conductive layers has poor structural stability, low strength, and uneven electrical and thermal conductivity. Especially when the battery core is thick, the heat generated inside the battery is difficult to dissipate quickly, which brings safety hazards. Second, the metal density of the conductive layer is large, and the proportion in the entire battery is also large, which seriously affects the energy density of the battery. Summary of the invention

[0003] In order to solve the above problems, the present invention provides a graphene composite current collector and a preparation method thereof. The graphene composite current collector is a core-shell structure composite current collector constructed of two parts, an electrically insulating core and a conductive shell. The conductive shell is coated on the outside of the electrically insulating core. The collector has the characteristics of good structural stability, high strength, light weight, fast conductivity, good heat dissipation, high energy density and high safety. A method for preparing a graphene composite current collector has the characteristics of simple process, strong reliability and high production efficiency, and is particularly suitable for large-scale industrial production.

[0004] As attached Figure 1 As shown, a graphene composite current collector includes an electrically insulating core and a conductive shell, and is a composite current collector with a core-shell structure, wherein the conductive shell is coated on the outside of the electrically insulating core; The material of the electrically insulating core is an electrically insulating composite material such as a polymer, including at least one of a polymer or a polymer precursor such as polyimide (PI), fluorinated polyimide (FPI), polyethylene (PE), polyamide (PA), polyetherimide (PEI), polyvinylidene fluoride (PVDF), polyethylene terephthalate (PET), meta-aramid (PMIA), polyphenylene sulfide (PPS), and an inorganic material such as aluminum oxide, aluminum nitride, and silicon oxide; The material of the conductive shell is a conductive composite material such as graphene, including at least one of graphene, graphene-like materials, carbon nanotubes, carbon fibers, carbon, aluminum, copper, magnesium, nickel, gold, silver and other conductive materials; The thickness of the electrically insulating core is 1 to 8 μm; The thickness of the conductive shell is 0.2-20 μm.

[0005] As attached Figure 2 As shown, a method for preparing a graphene composite current collector comprises the following steps: (1) preparing an electrically insulating core, preparing a polymer nanofiber composite membrane containing inorganic nanoparticles by an electrospinning method to obtain an electrically insulating core; (2) preparing a conductive shell, using an electrospinning method to prepare a polymer nanofiber composite film containing metal precursor particles, and closing the polymer nanofiber composite film containing metal precursor particles around the electrically insulating core in the cross-sectional direction, and then subjecting it to a laser induction process to obtain a graphene film containing metal particles, that is, to obtain a conductive shell of the composite current collector; (3) Roll-composite molding: The composite current collector having a conductive shell is subjected to flattening and densification treatments through multiple roll-composite moldings to obtain a graphene composite current collector.

[0006] Beneficial effects: The present invention provides a graphene composite current collector and a preparation method thereof, which has the characteristics of good structural stability, high strength, light weight, fast conductivity, good heat dissipation and high safety, and can achieve the technical effect of improving the energy density and safety of the battery; a graphene composite current collector preparation method has the characteristics of simple process, strong reliability and high production efficiency, and is particularly suitable for large-scale industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 Schematic diagram of the cross-section of a core-shell structure of a graphene composite current collector.

[0008] Figure 2 The present invention is a flow chart of a method for preparing a graphene composite current collector. In the figure: 1 - electrically insulating core, 2 - electrically conductive shell. DETAILED DESCRIPTION

[0009] Example 1: A graphene composite current collector and a method for preparing the same.

[0010] As attached Figure 1 and attached Figure 2 As shown, a graphene composite current collector is constructed of two parts, an electrically insulating core and a conductive shell, and is a composite current collector with a core-shell structure, wherein the conductive shell is coated on the outside of the electrically insulating core. The electrically insulating core is made of an electrically insulating composite material such as a polymer, and the conductive shell is made of a conductive composite material such as graphene. The material of the electrically insulating core is an electrically insulating composite material such as a polymer, including a polymer or a polymer precursor such as polyimide (PI), fluorinated polyimide (FPI), polyethylene (PE), polyamide (PA), polyetherimide (PEI), polyvinylidene fluoride (PVDF), polyethylene terephthalate (PET), meta-aramid (PMIA), polyphenylene sulfide (PPS), and at least one of inorganic materials such as aluminum oxide, aluminum nitride, and silicon oxide. In this embodiment, a polyimide (PI) composite material containing aluminum nitride nanoparticles is selected as the material of the electrically insulating core. In this embodiment, a polyimide (PI) polymer nanofiber composite film containing aluminum nitride nanoparticles prepared by electrostatic spinning is used as the core of the composite current collector. The material of the conductive shell is a conductive composite material such as graphene, including at least one of graphene, graphene-like materials, carbon nanotubes, carbon fibers, carbon, aluminum, copper, magnesium, nickel, gold, silver and other conductive materials. In this embodiment, a polyimide (PI) composite material containing copper chloride particles is selected as the precursor material of the conductive shell, and after laser induction processing, a graphene film containing metallic copper particles is obtained, that is, a conductive shell of graphene containing metallic copper particles is obtained. In this embodiment, the graphene film containing metallic copper particles is used as the shell of the composite current collector. The thickness of the electrically insulating core is 1-12 μm. In this embodiment, the thickness of the electrically insulating core is 6 μm. The thickness of the conductive shell is 0.2-15 μm. In this embodiment, the conductive shell has an annular structure, and the thickness of the conductive shell at its minimum point is 3 μm.

[0011] A method for preparing a graphene composite current collector comprises the following steps: (1) Preparation of an electrically insulating core The polyimide (PI) polymer nanofiber composite film containing aluminum nitride nanoparticles was prepared by electrospinning, and the polyimide (PI) nanofiber composite film with excellent heat resistance and flame retardancy was used as an electrically insulating core. In this embodiment, the thickness of the core was 6 μm. (2) Preparation of a conductive shell A polyimide (PI) composite fiber membrane containing copper chloride particles is prepared by an electrospinning method, and a polymer nanofiber composite membrane containing metal copper precursor particles is closed and composited around an electrically insulating core in the cross-sectional direction, and then subjected to a laser induction process to obtain a graphene film containing metal copper particles, i.e., a conductive shell of a composite current collector; in this embodiment, the graphene film containing metal copper particles is used as the shell of the composite current collector; in this embodiment, the thickness of the conductive shell of the composite current collector at its minimum thickness is 3 μm; (3) Roller composite molding The composite current collector with a conductive shell is subjected to flattening and densification treatments by multiple roll-pressing composite molding. In this embodiment, a graphene composite current collector with a thickness of 12 μm is obtained.

[0012] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A graphene composite current collector, characterized in that: The composite current collector comprises two parts, an electrically insulating core and a conductive shell, wherein the conductive shell is coated on the outside of the electrically insulating core; the material of the electrically insulating core is an electrically insulating composite material such as a polymer, and the material of the conductive shell is a conductive composite material such as graphene.

2. The graphene composite current collector according to claim 1, characterized in that The thickness of the electrically insulating core is 1-8 μm.

3. The graphene composite current collector according to claim 1, characterized in that The thickness of the conductive shell is 0.2-20 μm.

4. The graphene composite current collector according to claim 1, wherein the material of the electrically insulating core is an electrically insulating composite material such as a polymer, including at least one of a polymer or a polymer precursor such as polyimide (PI), fluorinated polyimide (FPI), polyethylene (PE), polyamide (PA), polyetherimide (PEI), polyvinylidene fluoride (PVDF), polyethylene terephthalate (PET), meta-aramid (PMIA), polyphenylene sulfide (PPS) and an inorganic material such as aluminum oxide, aluminum nitride, and silicon oxide.

5. The graphene composite current collector as claimed in claim 1, wherein the material of the conductive shell is a conductive composite material such as graphene, including at least one of graphene, graphene-like materials, carbon nanotubes, carbon fibers, carbon, aluminum, copper, magnesium, nickel, gold, silver and other conductive materials.

6. A method for preparing a graphene composite current collector. The following steps are involved: (1) preparing an electrically insulating core, preparing a polymer nanofiber composite membrane containing inorganic nanoparticles by an electrospinning method to obtain an electrically insulating core; (2) preparing a conductive shell, using an electrospinning method to prepare a polymer nanofiber composite film containing metal precursor particles, and closing the polymer nanofiber composite film containing metal precursor particles around the electrically insulating core in the cross-sectional direction, and then subjecting it to a laser induction process to obtain a graphene film containing metal particles, that is, to obtain a conductive shell of the composite current collector; (3) Roll-composite molding: The composite current collector having a conductive shell is subjected to flattening and densification treatments through multiple roll-composite moldings to obtain a graphene composite current collector.

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