CN-122025659-A - Composite current collector, preparation method thereof, pole piece and battery

CN122025659ACN 122025659 ACN122025659 ACN 122025659ACN-122025659-A

Abstract

The invention discloses a composite current collector and a preparation method thereof, a pole piece and a battery, wherein the composite current collector comprises a macromolecule base film layer, a copper metal layer, a metal diffusion barrier layer, an oxygen-containing sputtering layer and elements, wherein the macromolecule base film layer is positioned on the center layer of the composite current collector, the copper metal layer is positioned on two side surfaces of the macromolecule base film layer of the composite current collector, the metal diffusion barrier layer is positioned on two side surfaces of the copper metal layer of the composite current collector, the oxygen-containing sputtering layer is positioned on two side surfaces of the metal diffusion barrier layer of the composite current collector, and the elements on the outer side of the copper metal layer, the metal diffusion barrier layer and the inner side of the oxygen-containing sputtering layer are mutually doped to form a mixed transition structure. The copper layer, the metal diffusion barrier layer and the oxygen-containing sputtering layer form a mixed transition structure through element doping, so that a compact oxidation-resistant barrier is formed, low resistivity is maintained, on the basis of oxidation resistance, the conductivity of a copper matrix is maintained, interface energy is reduced through the mixed transition structure, a current collector is more stable, and the conductivity is further improved.

Inventors

SHEN PENGCHENG
LI XUEFA

Assignees

江阴纳力新材料科技有限公司

Dates

Publication Date: 20260512
Application Date: 20260306

Claims (10)

1. A composite current collector, comprising: The high polymer base film layer is positioned on the central layer of the composite current collector; copper metal layers positioned on both sides of the polymer-based film layer of the composite current collector; The metal diffusion barrier layers are positioned on two side surfaces of the copper metal layer of the composite current collector; the oxygen-containing sputtering layers are positioned on two side surfaces of the metal diffusion barrier layer of the composite current collector; the elements on the outer side of the copper metal layer, the metal diffusion barrier layer and the inner side of the oxygen-containing sputtering layer are mutually doped to form a mixed transition structure.
2. The composite current collector of claim 1 wherein the metal diffusion barrier layer is a tantalum metal layer or a titanium nitride layer.
3. The composite current collector of claim 1 wherein the oxygen-containing sputtered layer is one of a silicon oxide layer, a germanium oxide layer, and a silicon aluminum oxide layer.
4. The composite current collector of claim 1, wherein the metal diffusion barrier layer has a thickness of 1-2 nm and the oxygen-containing sputtered layer has a thickness of 3-7 nm.
5. The method for preparing a composite current collector according to claim 1, comprising the steps of: s1, preparing copper metal layers on two sides of a polymer base film layer to form a composite copper current collector; S2, preparing metal diffusion barrier layers on the surfaces of two sides of the composite copper current collector; s3, preparing oxygen-containing sputtering layers on the surfaces of two sides of the metal diffusion barrier layer; S4, post-processing.
6. The method of manufacturing a composite current collector according to claim 5, wherein in step S2, the metal diffusion barrier layer is manufactured by sputtering a tantalum metal layer or a titanium nitride layer on both surfaces of the composite copper current collector by using tantalum metal or titanium nitride as a target material through a magnetron sputtering process.
7. The method of claim 5, wherein in step S3, the oxygen-containing sputtering layer is prepared by using silicon oxide, oxide or silicon-aluminum composite as a target material and preparing a silicon oxide layer, a germanium oxide layer or a silicon-aluminum oxide layer on the two side surfaces of the metal diffusion barrier layer by using a magnetron sputtering process.
8. The method of manufacturing a composite current collector according to claim 5, wherein in step S4, the post-treatment is to cool the cavity after magnetron sputtering, then introduce inert gas, and take out the composite current collector after the cavity returns to normal pressure.
9. A pole piece characterized by comprising the composite current collector according to any one of claims 1 to 4 or prepared by the method according to any one of claims 5 to 8.
10. A battery comprising the electrode sheet of claim 9.

Description

Composite current collector, preparation method thereof, pole piece and battery Technical Field The invention relates to the technical field of batteries, in particular to a composite current collector, a preparation method thereof, a pole piece and a battery. Background With the rapid development of new energy and electronic technology, the cycle life, safety performance, energy density, etc. of batteries have become important. The current collector is an important component of the battery, and is used for collecting current generated by the active substances of the battery so as to form larger current to be output to the outside. The performance of the current collector directly affects the cycle life, energy density and safety of the battery. At present, copper foil and aluminum foil are mostly used as current collectors for positive and negative plates in lithium batteries and sodium batteries, but the current collectors have higher cost and larger quality, which is not beneficial to control of battery cost and improvement of energy density. In contrast, composite foils have significant advantages. The composite foil current collector generally adopts a sandwich structure, wherein an inner layer is a polymer high molecular layer, and two sides are metal conductive layers. Because the metal layer on the surface is thinner and the polymer layer in the composite current collector is lighter, the overall weight of the composite current collector can be effectively reduced, and the energy density of the lithium ion battery is improved. In addition, when thermal runaway occurs in the lithium ion battery, the thinner metal layer on the surface of the composite current collector is easier to break than the traditional foil, so that connection of active substances and the current collector is isolated, and the continuous development of the thermal runaway is prevented. Although the composite foil has the advantages of low cost and light weight, the composite copper foil current collector may be at risk of oxidation due to storage conditions after being manufactured. The existing Cr metal passivation technology cannot completely isolate oxygen, so that an oxidation phenomenon can occur in the electroplated film, the quality change risk of a copper layer is increased, and the cycle life and the safety performance of the battery are further reduced. Disclosure of Invention The invention aims to provide a composite current collector, a preparation method thereof, a pole piece and a battery, and oxidation resistance is improved on the basis of keeping the excellent performance of the composite current collector. In order to achieve the above purpose, the technical scheme provided by the invention is as follows: the invention is realized by the following technical scheme: a first aspect of the present application provides a composite current collector comprising: The high polymer base film layer is positioned on the central layer of the composite current collector; copper metal layers positioned on both sides of the polymer-based film layer of the composite current collector; The metal diffusion barrier layers are positioned on two side surfaces of the copper metal layer of the composite current collector; the oxygen-containing sputtering layers are positioned on two side surfaces of the metal diffusion barrier layer of the composite current collector; the elements on the outer side of the copper metal layer, the metal diffusion barrier layer and the inner side of the oxygen-containing sputtering layer are mutually doped to form a mixed transition structure. In order to optimize the technical scheme, the specific measures adopted further comprise: The metal diffusion barrier layer is a tantalum metal layer or a titanium nitride layer. The oxygen-containing sputtering layer is one of a silicon oxide layer, a germanium oxide layer and a silicon aluminum oxide layer. The thickness of the metal diffusion barrier layer is 1-2 nm, and the thickness of the oxygen-containing sputtering layer is 3-7 nm. The second aspect of the application provides a preparation method of the composite current collector, comprising the following steps: s1, preparing copper metal layers on two sides of a polymer base film layer to form a composite copper current collector; S2, preparing metal diffusion barrier layers on the surfaces of two sides of the composite copper current collector; s3, preparing oxygen-containing sputtering layers on the surfaces of two sides of the metal diffusion barrier layer; S4, post-processing. In step S2, the preparation method of the metal diffusion barrier layer includes sputtering a tantalum metal layer or a titanium nitride layer on two side surfaces of the composite copper current collector by using tantalum metal or titanium nitride as a target material through a magnetron sputtering process. In the step S3, the preparation method of the oxygen-containing sputtering layer comprises the step of preparing a sil