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CN-122025663-A - Composite current collector, preparation method thereof, magnesium ion battery and power utilization device

CN122025663ACN 122025663 ACN122025663 ACN 122025663ACN-122025663-A

Abstract

A composite current collector comprises a conductive composite base film, a three-dimensional porous conductive layer positioned on the conductive composite base film and a first modified layer positioned on at least part of the surface of the three-dimensional porous conductive layer on the conductive composite base film, wherein the conductive composite base film comprises a polymer base film and a first magneiphilic metal, the surface of the polymer base film is provided with a groove, the first magneiphilic metal is positioned in the groove, the three-dimensional porous conductive layer is positioned on one side of the first magneiphilic metal far away from the polymer base film and comprises at least two alloy layers arranged in a laminated mode, the alloy layers comprise copper and second magneiphilic metal, the content of the second magneiphilic metal in the plurality of alloy layers decreases from one side close to the conductive composite base film to one side far away from the conductive composite base film, and the first modified layer comprises covalent organic frame materials. The composite current collector can improve the deposition of magnesium ions, inhibit dendrite growth, reduce interface side reactions and improve the cycling stability of the magnesium ion battery.

Inventors

  • CAI BIYA
  • WANG RONGFU
  • ZHU HAIFENG
  • YUAN CHANGLI

Assignees

  • 深圳市汉嵙新材料技术有限公司

Dates

Publication Date
20260512
Application Date
20260415

Claims (10)

  1. 1. A composite current collector is characterized by comprising a conductive composite base film, a three-dimensional porous conductive layer positioned on the conductive composite base film, and a first modified layer positioned on at least part of the surface of the three-dimensional porous conductive layer on the conductive composite base film, The conductive composite base film comprises a polymer base film and a first magnesium-philic metal, wherein the surface of the polymer base film is provided with a groove, and the first magnesium-philic metal is positioned in the groove; the three-dimensional porous conductive layer is positioned on one side of the first magneignophilic metal far away from the polymer base film and comprises at least two alloy layers arranged in a laminated mode, wherein the alloy layers comprise copper and the second magneignophilic metal, and The content of the second magnesian metal in the plurality of alloy layers decreases from one side close to the conductive composite base film to one side far away from the conductive composite base film; the first modifying layer includes a covalent organic framework material.
  2. 2. The composite current collector of claim 1 wherein the porosity of a plurality of said alloy layers decreases from a side proximate to said conductive composite base film to a side distal from said conductive composite base film.
  3. 3. A composite current collector according to claim 1 or 2 wherein said alloy layer of said at least two stacked layers comprises a bottom layer, an intermediate layer and a surface layer disposed in sequence along a distance from said conductive composite base film; The mass percentage of the second magnesian metal in the bottom layer is 8-12%, the mass percentage of the second magnesian metal in the middle layer is 3-7%, and the mass percentage of the second magnesian metal in the surface layer is 0.5-2%; the porosity of the bottom layer is 55% to 65%, the porosity of the middle layer is 45% to 55%, and the porosity of the surface layer is 35% to 45%.
  4. 4. The composite current collector of claim 1 wherein said first modifying layer further satisfies at least one of the following conditions: (1) The covalent organic framework material in the first modified layer comprises a covalent organic framework material comprising pyridine nitrogen and/or sulfonic acid groups; (2) The first modified layer has a thickness of 0.5 μm to 3 μm.
  5. 5. The composite current collector of claim 1 wherein said grooves satisfy at least one of the following conditions: (1) The shape of the groove comprises a conical shape; (2) The number of the grooves is plural, the average depth of the grooves is 2-5 μm, the average equivalent diameter of the grooves is 10-100 μm, and the distance between two adjacent grooves is 500-10000 μm.
  6. 6. The composite current collector of claim 1, wherein the composite current collector further satisfies at least one of the following conditions: (1) The first magnesium-philic metal is filled in the groove, and is higher than the surface of the polymer base film, and the thickness of the higher part is 50 nm-100 nm; (2) The thickness of the polymer base film is 4 μm to 10 μm; (3) The material of the polymer-based film comprises at least one of polypropylene and polyimide; (4) The first magnesium-philic metal and the second magnesium-philic metal are each independently selected from at least one of Au, bi, and Sb.
  7. 7. A method of preparing the composite current collector of claim 1, comprising the steps of: Providing the polymer base film with the grooves on the surface, and depositing the first magnesian metal in the grooves through magnetron sputtering to prepare the conductive composite base film; arranging at least two composite layers on the surface of the conductive composite base film, wherein the composite layers comprise an alloy and a pore-forming base material, the composite layers are prepared by magnetron co-sputtering, the alloy comprises copper and second magneium-philic metals, and the content of the second magneium-philic metals in the composite layers decreases from one side close to the conductive composite base film to one side far away from the conductive composite base film; removing the pore-forming substrate material of each layer by etching to form the alloy layer, and preparing the three-dimensional porous conductive layer; And arranging covalent organic framework material dispersion liquid on the surface of the three-dimensional porous conductive layer, drying to form the first modified layer, and preparing the composite current collector.
  8. 8. A magnesium ion battery comprising a positive electrode, a separator, a negative electrode current collector and an electrolyte, wherein the negative electrode current collector comprises the composite current collector according to any one of claims 1 to 6.
  9. 9. The magnesium-ion battery of claim 8, wherein the magnesium-ion battery further satisfies at least one of the following conditions: (1) The separator comprises a glass fiber base film and a second modified layer positioned on the surface of the glass fiber base film, wherein the second modified layer comprises covalent organic framework materials; (2) The separator comprises a glass fiber base film and a second modified layer positioned on the surface of the glass fiber base film, wherein the second modified layer comprises a covalent organic framework material, and the covalent organic framework material in the second modified layer comprises a covalent organic framework material containing at least one group of imino, carbonyl and triazinyl; (3) The electrolyte includes water, magnesium salt, and an additive including at least one of boric acid, trimethyl phosphate, and glucose.
  10. 10. An electrical device comprising a magnesium ion battery according to claim 8 or 9.

Description

Composite current collector, preparation method thereof, magnesium ion battery and power utilization device Technical Field The application relates to the technical field of electrochemical energy storage, in particular to a composite current collector, a preparation method thereof, a magnesium ion battery and an electric device. Background The magnesium element has rich energy storage in the crust, mature smelting technology and high theoretical volume capacity due to inherent double-electron reaction characteristic of magnesium, and the magnesium ion battery has wide application prospect in the energy storage market. In the conventional magnesium ion battery, a thicker magnesium foil is generally used as a metal anode, which easily causes an excessive anode active material, thereby reducing the energy density of the battery. In this way, the battery energy density can be effectively improved by adopting the magnesium ion battery without the negative electrode. In general, a negative electrode-free magnesium ion battery does not adopt a negative electrode structure (a negative electrode current collector and a negative electrode active material), but uses the negative electrode current collector as a carrier for active ion electroplating stripping, and serves as a negative electrode, when the battery is charged, mg 2+ of a positive electrode shuttles to the surface of the negative electrode current collector to generate electroplating reaction, however, uneven deposition of magnesium metal and repeated growth of an unstable SEI film easily cause rapid consumption of active magnesium ions and even growth of irregular magnesium dendrites, and the electrochemical stability of the magnesium ion battery is seriously deteriorated. Disclosure of Invention In view of the above, the present application provides a composite current collector, a method for preparing the same, a magnesium ion battery, and an electric device, so as to solve the above-mentioned technical problems. In order to achieve the above object, in a first aspect, the present application provides a composite current collector, which comprises a conductive composite base film, a three-dimensional porous conductive layer located on the conductive composite base film, and a first modified layer located on at least part of the surface of the three-dimensional porous conductive layer on the conductive composite base film, wherein the conductive composite base film comprises a polymer base film and a first magneiphilic metal, the surface of the polymer base film is provided with a groove, the first magneiphilic metal is located in the groove, the three-dimensional porous conductive layer is located on one side of the first magneiphilic metal away from the polymer base film, the three-dimensional porous conductive layer comprises at least two alloy layers arranged in a laminated manner, the alloy layers comprise copper and a second magneiphilic metal, the content of the second magneiphilic metal in the plurality of alloy layers decreases from one side close to the conductive composite base film to one side away from the conductive composite base film, and the first modified layer comprises a covalent organic frame material. Based on the first aspect, in some embodiments, the porosity of the plurality of alloy layers decreases from a side proximal to the conductive composite base film to a side distal to the conductive composite base film. Based on the first aspect, in some embodiments, the alloy layer of the at least two stacked layers includes a bottom layer, an intermediate layer, and a surface layer disposed in order along a distance from the conductive composite base film, the mass percent of the second magnesium-philic metal in the bottom layer is 8% to 12%, the mass percent of the second magnesium-philic metal in the intermediate layer is 3% to 7%, the mass percent of the second magnesium-philic metal in the surface layer is 0.5% to 2%, the porosity of the bottom layer is 55% to 65%, the porosity of the intermediate layer is 45% to 55%, and the porosity of the surface layer is 35% to 45%. Based on the first aspect, in some embodiments, the covalent organic framework material in the first modified layer comprises a covalent organic framework material comprising pyridine nitrogen and/or sulfonic acid groups. Based on the first aspect, in some embodiments, the thickness of the first modified layer is 0.5 μm to 3 μm. Based on the first aspect, in some embodiments, the shape of the groove comprises a conical shape. Based on the first aspect, in some embodiments, the number of grooves is a plurality, the average depth of the grooves is 2 μm to 5 μm, the average equivalent diameter of the grooves is 10 μm to 100 μm, and the distance between two adjacent grooves is 500 μm to 10000 μm. Based on the first aspect, in some embodiments, the first magnesium-philic metal fills in the grooves and the first magnesium-philic metal is above the surface of the polymer