CN-122025654-A - Functional current collector, preparation method thereof and battery

CN122025654ACN 122025654 ACN122025654 ACN 122025654ACN-122025654-A

Abstract

The invention provides a functional current collector, a preparation method thereof and a battery, wherein the functional current collector comprises a polymer film, a seed layer and a metal thickening layer, wherein the seed layer and the metal thickening layer are arranged on two side surfaces of the polymer film in a laminated mode, the seed layer is arranged between the polymer film and the metal thickening layer, the functional current collector also comprises a functional layer arranged between the seed layer and the metal thickening layer on at least one side, the functional layer is made of a metal material, the melting point is higher than 1300 ℃, and the difference between the melting point of the functional layer and the melting point of the seed layer is higher than 250 ℃. The invention can obtain the functional current collector with low defects, thereby improving the stability of the structure and the performance of the functional current collector.

Inventors

ZHU ZHONGYA
XIA JIANZHONG
ZENG LAIYUAN
LI XUEFA

Assignees

扬州纳力新材料科技股份有限公司

Dates

Publication Date: 20260512
Application Date: 20260205

Claims (10)

1. A functional current collector, characterized in that the functional current collector comprises a polymer film; The seed layer and the metal thickening layer are arranged on the two side surfaces of the polymer film in a stacked mode, and the seed layer is positioned between the polymer film and the metal thickening layer; the functional current collector further comprises a functional layer arranged between the seed layer and the metal thickening layer on at least one side; the functional layer is made of metal material, the melting point is higher than 1300 ℃, and the difference between the melting point of the functional layer and the melting point of the seed layer is higher than 250 ℃.
2. The functional current collector of claim 1, wherein the functional current collector satisfies at least one of the following conditions: A1, the polymer film is made of any one or a combination of at least two of polyethylene terephthalate, polypropylene, polybutylene terephthalate, polyethylene naphthalate, polyethylene, polypropylene, polyvinyl chloride, polyvinylidene fluoride, polytetrafluoroethylene, polyphenylene sulfide, polyphenyl ether, polystyrene or polyimide; A2, the thickness of the polymer film is 1.0-10 mu m; A3, the seed layer is made of copper or copper alloy; and A4, the thickness of the seed layer is 50-100 nm.
3. The functional current collector of claim 1, wherein the functional layer satisfies at least one of the following conditions: B1, the thickness of the functional layer is 2-50 nm; B2, the material of the functional layer comprises any one or a combination of at least two of titanium, titanium alloy, zirconium alloy, tantalum alloy, nickel alloy, chromium alloy, molybdenum or molybdenum alloy; b3, the functional layer is provided with a crystalline structure, and the crystalline phase of the crystalline structure in the functional layer comprises any one or a combination of at least two of a body-centered cubic, a face-centered cubic or a close-packed hexagonal; B4, the functional layer is provided with a crystalline structure, and the content of the crystalline structure in the functional layer is 0.05-5wt%; B5, the functional layer is provided with an amorphous structure, and the element composition of the amorphous structure in the functional layer comprises any one or a combination of at least two of titanium, zirconium, tantalum, nickel, chromium and molybdenum; B6, the crystallinity relation among the seed layer, the functional layer and the metal thickening layer is that the seed layer is < the functional layer is < the metal thickening layer; b7, the density rho 1 of the functional layer meets 0.9 rho 0 ≤ρ 1 ≤ρ 0 , wherein rho 0 is the density of the material used by the functional layer; b8, the defect area ratio of the interface between the functional layer and the metal thickening layer is less than or equal to 5%; and B9, the functional layer comprises a metal sub-functional layer and a metal oxide sub-functional layer, and the thickness of the metal oxide functional layer is 5-15 nm.
4. A functional current collector according to any one of claims 1 to 3, wherein the metal thickening layer satisfies at least one of the following conditions: c1, the material of the metal thickening layer comprises copper or copper alloy; C2, the thickness of the metal thickening layer is 500-2000 nm; c3, the purity of the metal thickening layer is more than or equal to 99.9wt%.
5. The functional current collector of claim 1, further comprising protective layers disposed on both sides of the metal thickening layer; The material of the protective layer comprises any one or a combination of at least two of chromium oxide, copper-organic acid complex, copper-imidazole complex, silane coupling agent, nickel, chromium, nichrome, nickel oxide, graphite, carbon black, carbon nano quantum dots, carbon nano tubes, carbon nano fibers or graphene, and/or the thickness of the protective layer is 5-100 nm.
6. A method for preparing the functional current collector according to any one of claims 1 to 5, comprising: Performing first deposition on both side surfaces of the polymer film to form a seed layer; Performing second deposition on at least one side surface of the seed layer to form a functional layer, thereby obtaining a first current collector piece; electroplating is carried out on the two side surfaces of the first current collector piece so as to form a metal thickening layer.
7. The method according to claim 6, wherein the second deposition method is a magnetron sputtering method, and wherein the magnetron sputtering method in the second deposition satisfies at least one of the following conditions: D1, the pressure in the magnetron sputtering cabin in the second deposition is 0.01-0.2 Pa; d2, the gas source of the magnetron sputtering method in the second deposition comprises argon; D3, the target current of the magnetron sputtering method in the second deposition is 10-40 a; and D4, sputtering time of the magnetron sputtering method in the second deposition is 0.5-30 s.
8. The method of claim 6 or 7, wherein the electroplating process satisfies at least one of the following conditions: E1, the temperature of the electroplating solution in the electroplating process is 15-40 ℃; E2, the average cathode current density in the electroplating process is 0.5-5A/dm 2 ; E3, the initial current density in the electroplating process is not lower than 0.1ASD; And E4, electroplating for 2-15 min.
9. The method according to claim 6 or 7, wherein the plating solution used for the plating comprises 70-180 g/L copper sulfate, 60-120 g/L sulfuric acid and 40-100 mg/L hydrochloric acid, and the solvent is water; and/or the electroplating solution further comprises an electroplating solution additive, wherein the electroplating solution additive comprises a brightening agent, a leveling agent and an inhibitor, and the electroplating solution additive meets at least one of the following conditions: f1, the concentration of the brightening agent in the electroplating solution is 0.5-10 mg/L; f2, the concentration of the leveling agent in the electroplating solution is 1-50 mg/L; f3, the concentration of the inhibitor in the electroplating solution is 10-500 mg/L; f4, the leveling agent comprises a nitrogen-containing compound, wherein the nitrogen-containing compound comprises any one or a combination of at least two of 2-mercaptopyridine, benalalu, polyethyleneimine, polyvinylpyrrolidone and 1, 3-bis (1-imidazolyl) propane; F5, the brightening agent comprises an organic sulfur compound; wherein the organic sulfur compound comprises sodium polydithio-dipropyl sulfonate (SPS) and/or sodium 3-mercapto-1-propane sulfonate (MPS); f6, the inhibitor comprises any one or a combination of at least two of polyethylene glycol, polypropylene glycol or polyether.
10. A battery, characterized in that the battery comprises the functional current collector according to any one of claims 1 to 6 or the functional current collector prepared by the method for preparing a functional current collector according to any one of claims 7 to 9.

Description

Functional current collector, preparation method thereof and battery Technical Field The invention relates to the technical field of current collectors, in particular to a functional current collector, a preparation method thereof and a battery. Background At present, a composite copper current collector based on a high-molecular polymer film is widely focused and applied in the new energy industry. The preparation process of the composite copper current collector generally comprises the following two steps of firstly, depositing a layer of copper on a high polymer film (such as polypropylene, polyethylene, polyester and the like) by adopting a Physical Vapor Deposition (PVD) method to prepare a semi-finished product of the composite copper current collector with certain conductivity. And then, further processing the semi-finished product of the composite copper current collector by electroplating to thicken the conductive copper layer, thereby preparing the composite copper current collector with good conductivity. Compared with the traditional current collector (copper foil), the composite copper current collector based on the high-molecular polymer film has the characteristics of low cost, light weight, good internal insulation and the like. These features enable the composite current collector to reduce the cost of the battery and to improve the energy density and safety of the battery when applied in the battery. However, the preparation of the current composite copper current collector has the following problems that film surface copper layers contacted with each other can be adhered in the winding process of preparing a semi-finished product of the composite copper current collector by adopting winding PVD equipment to deposit the copper layers on an ultrathin high polymer base film, so that the adhered film surface can be torn in the unreeling process of the subsequent process (electroplating), the film surface microscopic copper layers can fall off to generate microscopic defects, copper cannot be deposited due to non-conduction near defect points in the electroplating process, and finally the prepared composite copper current collector has microscopic defects, so that the performance and the application of the composite current collector are affected. Therefore, in order to solve the above problems, it is necessary to develop a new method for preparing a composite copper current collector, so as to prepare a low-defect composite copper current collector, so as to promote popularization and application of the composite copper current collector. Disclosure of Invention Aiming at the defects of the prior art, the invention aims to provide a functional current collector, a preparation method thereof and a battery, and the functional current collector with low defects can be obtained, so that the stability of the structure and performance of the functional current collector is improved, and the popularization and application of the functional current collector are promoted. To achieve the purpose, the invention adopts the following technical scheme: In a first aspect, the present invention provides a functional current collector, the functional current collector including a polymer film, and a seed layer and a metal thickening layer stacked on both side surfaces of the polymer film, wherein the seed layer is located between the polymer film and the metal thickening layer. The functional current collector further comprises a functional layer arranged between the seed layer and the metal thickening layer on at least one side. The functional layer is made of metal material, the melting point is higher than 1300 ℃, and the difference between the melting point of the functional layer and the melting point of the seed layer is higher than 250 ℃. The reason for causing mutual adhesion of the seed layers of the film surfaces in the composite copper current collector semi-finished film roll prepared by PVD is that the metal in the seed layers is relatively active and in a metastable state, and the seed layers on the two surfaces can be fused with each other, so that the seed layers of the film surfaces are adhered, and further microscopic defects are generated. Based on the method, a stable functional layer is constructed on at least one surface of the seed layer in the functional current collector, the existence of the functional layer is ①, the contact of the seed layers on two sides of the semi-finished product after winding can be blocked, the mutual adhesion between the seed layers is avoided, the ② can protect the seed layer on the film surface of the semi-finished product from being scratched and oxidized in the winding process, and the surface defect of the composite copper current collector is reduced. Furthermore, the functional layer is made of a metal material with a melting point of more than 1300 ℃ and a difference value between the melting point of the functional layer and the melting point of th