CN117996088A - Composite current collector, composite pole piece, lithium battery and preparation method - Google Patents
Composite current collector, composite pole piece, lithium battery and preparation method Download PDFInfo
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- CN117996088A CN117996088A CN202410209108.5A CN202410209108A CN117996088A CN 117996088 A CN117996088 A CN 117996088A CN 202410209108 A CN202410209108 A CN 202410209108A CN 117996088 A CN117996088 A CN 117996088A
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- 239000002131 composite material Substances 0.000 title claims abstract description 183
- 238000002360 preparation method Methods 0.000 title claims abstract description 27
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 title description 6
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- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 1
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Classifications
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/64—Carriers or collectors
- H01M4/66—Selection of materials
- H01M4/665—Composites
- H01M4/667—Composites in the form of layers, e.g. coatings
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
- C23C14/06—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the coating material
- C23C14/14—Metallic material, boron or silicon
- C23C14/20—Metallic material, boron or silicon on organic substrates
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
- C23C14/22—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the process of coating
- C23C14/24—Vacuum evaporation
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
- C23C14/22—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the process of coating
- C23C14/24—Vacuum evaporation
- C23C14/28—Vacuum evaporation by wave energy or particle radiation
- C23C14/30—Vacuum evaporation by wave energy or particle radiation by electron bombardment
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
- C23C14/22—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the process of coating
- C23C14/54—Controlling or regulating the coating process
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/052—Li-accumulators
- H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
- H01M2004/028—Positive electrodes
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Materials Engineering (AREA)
- Organic Chemistry (AREA)
- Metallurgy (AREA)
- Mechanical Engineering (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Toxicology (AREA)
- Manufacturing & Machinery (AREA)
- Composite Materials (AREA)
- Cell Electrode Carriers And Collectors (AREA)
Abstract
The disclosure provides a composite current collector, a composite pole piece, a lithium ion battery and a preparation method thereof, and belongs to the field of batteries. The composite current collector comprises a high polymer layer and a conductive layer, wherein the conductive layer is formed on at least one side of the high polymer layer by adopting ion beam auxiliary deposition, so that the performance index of the composite current collector meets at least one of the following: the resistivity of the composite current collector is reduced to a first numerical range; the fracture strain of the composite current collector is increased to a second numerical range; the fatigue resistance cycle of the composite current collector is promoted to a third numerical range for a round; the bonding force between the polymer layer and the conductive layer is increased to a fourth value range. The resistivity of the composite current collector is close to that of a corresponding blocky conductive material, the binding force between the high polymer layer and the conductive layer is large, the tensile property and fatigue resistance of the composite current collector are good, and the electrochemical performance of a corresponding lithium ion battery is good.
Description
Technical Field
The disclosure relates to the field of batteries, in particular to a composite current collector, a composite pole piece, a lithium battery and a preparation method.
Background
Current collectors are one of the important components of lithium ion batteries and function to carry active materials, collect and conduct electrons. The ideal lithium ion battery current collector should satisfy: high conductivity, good chemical and electrochemical stability, high mechanical strength, good compatibility and binding force with electrode active substances, low cost, easy obtainment, light weight and the like. The traditional current collector generally takes aluminum foil as a positive current collector and copper foil as a negative current collector. However, copper foil and aluminum foil are difficult to meet the increasingly high performance requirements of people on lithium ion battery current collectors. To improve current collector performance, researchers have deposited metal films on the surface of a polymeric substrate to prepare a composite current collector. Compared with the traditional metal foil, the composite current collector has the advantages of high conductivity, low cost and light weight.
However, the existing composite current collector generally adopts a metal film obtained by a traditional PVD mode, and the deposition mode is rapid stacking of a large number of metal atoms, so that a large number of lattice defects and microscopic holes exist in the metal film in the deposition process, and the resistivity of the metal film is far higher than that of bulk metal by 1.5-4.0 mu omega cm. Although the conductive film obtained by post-treatment means-heat treatment of the composite current collector has the characteristics of low residual stress and low defect, the defect of the microstructure of the composite current collector obtained by the treatment method is still relatively large, and the resistivity does not reach the ideal effect. Moreover, the tensile property and the fatigue resistance of the existing composite current collector are not ideal, and no relevant report for testing the tensile property and the fatigue resistance of the composite current collector exists in the prior art.
Therefore, it is of great significance to provide a composite current collector, a composite pole piece, a lithium battery and a preparation method for solving or at least alleviating at least one of the above technical problems.
Disclosure of Invention
In view of the above technical problems, the present disclosure provides a composite current collector, a composite pole piece, a lithium battery and a preparation method thereof, so as to solve or at least alleviate at least one technical problem existing in the composite current collector, the composite pole piece and the lithium battery.
According to a first aspect of the present disclosure, there is provided a composite current collector comprising: the conductive layer is formed on at least one side of the polymer layer by adopting ion beam auxiliary deposition, so that the performance index of the composite current collector meets at least one of the following:
The resistivity of the composite current collector is reduced to a first numerical range;
The fracture strain of the composite current collector is increased to a second numerical range;
the fatigue resistance cycle of the composite current collector is promoted to a third numerical range for a round;
the bonding force between the polymer layer and the conductive layer is increased to a fourth value range.
Further, the first numerical range of the resistivity of the composite current collector is ρ 1～(ρ1 +3) μΩ·cm, where ρ 1 represents the resistivity of the bulk conductive material corresponding to the conductive material of the conductive layer.
Further, the second value range of the fracture strain of the composite current collector is 0 to 50%.
Further, the third numerical range of the fatigue cycle resistance of the composite current collector is 100-1000000 weeks under the condition of the strain range of 0.1-5%.
Further, the fourth range of values of the bonding force between the polymer layer and the conductive layer is greater than 5N/15mm.
Further, the thickness of the polymer layer is 4.5 to 12 μm.
Further, the thickness of the conductive layer is 0.1 to 2 μm.
Further, the conductive layer is a metal layer.
Further, the conductive layer is formed on at least one side of the polymer layer by ion beam assisted deposition while thermally evaporating.
Further, the composite current collector is a positive electrode current collector.
According to a second aspect of particular embodiments of the present disclosure, the present disclosure provides a composite pole piece comprising any one of the composite current collectors as described above.
According to a third aspect of the present disclosure, there is provided a lithium ion battery comprising any of the composite pole pieces as described above.
According to a fourth aspect of the present disclosure, there is provided a method of preparing a composite current collector as described in any one of the preceding claims, comprising the steps of:
step S1, providing a high polymer layer;
Step S2, depositing a conductive layer on at least one side of the high polymer layer by ion beam assisted deposition,
Wherein, the performance index of the composite current collector obtained by the preparation method meets at least one of the following:
The resistivity of the composite current collector is reduced to a first numerical range;
The fracture strain of the composite current collector is increased to a second numerical range;
the fatigue resistance cycle of the composite current collector is lifted to a third numerical range for a round;
And the binding force between the high polymer layer and the conductive layer is increased to a fourth numerical range.
Further, in step S2, the conductive layer is formed on at least one side of the polymer layer by ion beam assisted deposition while thermally evaporating.
Further, step S2 includes the steps of:
Placing the polymer layer into a reaction cavity, and vacuumizing to form a vacuum environment in the reaction cavity;
Introducing working gas into the reaction cavity, keeping the vacuum degree of the reaction cavity at 1-4 multiplied by 10 -3 Pa, opening an ion source, and adjusting beam current and energy to generate glow discharge;
The thermal evaporation source is turned on to evaporate the vapor deposition material, and in the glow discharge region, the vapor deposition atoms are accelerated and given higher energy, and finally deposited on the polymer layer to form a conductive layer.
Further, step S2 includes the steps of:
placing the polymer layer into a reaction cavity, and vacuumizing until the vacuum degree of the reaction cavity is higher than 10 -3 Pa;
Introducing working gas into the reaction cavity at a flow rate of 0-30 sccm, keeping the vacuum degree of the cavity at 1-4 multiplied by 10 -3 Pa, opening an ion source, and keeping the beam energy at 50-200 eV to generate glow discharge, wherein the working gas is Ar gas;
The ion source beam current is 0-500 eV, the thermal evaporation source is turned on to evaporate the evaporation material, the evaporation atoms are accelerated and endowed with higher energy in the glow discharge area, and finally, the conductive layer is formed on the polymer layer by deposition.
Further, the first numerical range of the resistivity of the composite current collector obtained by the preparation method is ρ 1～(ρ1 +3) μΩ·cm, wherein ρ 1 represents the resistivity of the bulk conductive material corresponding to the conductive material of the conductive layer.
Further, the second numerical range of the fracture strain of the composite current collector obtained by the preparation method is 0-50%.
Further, the third numerical range of fatigue resistance cycle is 100-1000000 weeks under the condition that the strain range of the composite current collector obtained by the preparation method is 0.1-5%.
Further, the fourth numerical range of the binding force between the high polymer layer and the conductive layer in the composite current collector obtained by the preparation method is more than 5N/15mm.
According to a fifth aspect of particular embodiments of the present disclosure, the present disclosure provides a method of making a composite pole piece, comprising a method of making any one of the composite current collectors described above.
According to a sixth aspect of particular embodiments of the present disclosure, there is provided a method of making a lithium ion battery comprising a method of making any of the composite pole pieces described above.
Compared with the prior art, the scheme of the embodiment of the disclosure has at least the following beneficial effects:
(1) The composite current collector comprises a high polymer layer and a conductive layer, wherein the conductive layer is formed on at least one side of the high polymer layer by adopting ion beam auxiliary deposition, the high polymer layer is bombarded by adopting high-energy ion beams during deposition, conductive atoms and high-energy ions are deposited to reach the surface of the high polymer layer at the same time, and the deposited atoms obtain energy through ion bombardment, so that the mobility of the deposited atoms is improved, different crystal growth and crystal structures are caused, and the conductivity and interface bonding capability performance of the composite current collector are improved. In addition, the ion bombardment releases energy, and the ion bombardment and the electron generate inelastic collision, and the elastic collision and the atom generate the elastic collision, the ion bombardment energy is transferred to the deposited conductive atom, the energy of the conductive atom is improved, some impact atoms with higher energy generate secondary collision, namely cascade collision, the cascade collision causes intense atom movement along the incidence direction of the ion, so that an interface transition region of the film layer atom and the matrix atom is formed, and the concentration value of the film layer atom and the matrix atom in the interface transition region is gradually transited. The cascade collision completes the energy transfer of ions to the atoms of the membrane layer, increases the migration capacity and chemical activation capacity of the membrane atoms, is beneficial to adjusting the atomic lattice arrangement of two phases, and improves the interface binding force between the high polymer layer and the conductive layer; and the conductive layer film with low lattice defect, low microcosmic holes and complete crystallization is obtained by combining the process conditions of ion energy, arrival ratio of ion deposition particles, ion-film-deposition rate, gas content, substrate temperature and the like.
(2) According to the preparation method of the composite current collector, the conductive layer is deposited on the surface of the high polymer layer by adopting ion-assisted deposition, so that the composite current collector with fewer defects and smaller microscopic holes is obtained, and the resistivity of the conductive layer is close to that of a corresponding block-shaped conductive material. And further, the technical problem that the resistivity of the metal thin film is far higher than that of a block metal is caused by a large number of lattice defects and microscopic holes in the metal conductive thin film in the deposition process due to the fact that the conductive layer in the existing composite current collector is rapidly stacked by a large number of metal atoms is solved. In the preparation method of the composite current collector, the high-energy ion bombardment increases the surface roughness of the high polymer layer, so that the adhesive force of the conductive layer on the surface of the high polymer layer is increased; and the ion beam assisted deposition process is a process in which physical and chemical effects act simultaneously in the ion implantation process, and physical adsorption and chemical adsorption exist between the conductive layer and the high polymer layer, so that the binding force between the conductive layer and the high polymer layer is further improved. The preparation method of the composite current collector can also increase the adhesive force fatigue resistance of the composite current collector under the condition of ensuring the reduction of the resistivity, and solves the technical problems of weak interface bonding capability and high resistivity of a high polymer layer and a metal layer in the existing method.
(3) The composite current collector provided by the disclosure adopts ion beam auxiliary deposition to prepare the conductive layer while vapor deposition, ion bombardment can increase the kinetic energy of vapor deposition particles, the density of the conductive film layer is improved, the ion bombardment destroys the growth condition of columnar crystals, and is converted into a dense anisotropic structure, so that the conductivity of the conductive layer is improved, and the overall conductivity of the composite current collector is further improved; the ion bombardment in the deposition process forces atoms to be in an unbalanced position, and the high-energy particles bombard the high-molecular layer to enable the surface of the high-molecular layer to generate compressive stress, so that the surface of the high-molecular layer is strengthened, the bonding force of an interface is improved, and the thermal stress and the growth stress of the interface are relieved.
(4) The tensile property and the fatigue resistance of the composite current collector are tested, and the problem that the tensile property and the fatigue resistance of the composite current collector are not tested in the prior art is solved. The ion-assisted deposition increases the kinetic energy of vapor deposition particles and the film forming energy, the increase of the kinetic energy can increase the mechanical interlocking of metal particles and the surface of the high polymer layer, and the increase of the film forming energy can induce the microstructure to generate grain growth, so that a more ideal microstructure is obtained. And the tensile property, the fatigue property and the interface bonding capability are strongly related to the compactness of the microstructure, and the better bonding force and the denser microstructure can improve the fatigue life of the tensile and material. The fracture strain of the composite current collector can reach 0-50% through testing, and the third numerical range of fatigue resistance cycle is 100-1000000 weeks under the condition of 0.1-5% strain range, which cannot be realized by the prior art.
(5) The composite current collector has an insulating polymer layer and a light and thin conducting layer structure, and can cut off or reduce short-circuit current in a short time by fusing the insulating material of the polymer layer to effectively prevent thermal runaway of the battery when the battery is in short circuit.
(6) The composite current collector disclosed by the invention adopts the polymer layer as the base material, the cost is lower, the density of the polymer organic material is lower, the weight of the composite current collector can be greatly reduced, and the weight energy density of the battery is improved.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the disclosure and together with the description, serve to explain the principles of the disclosure. It will be apparent to those of ordinary skill in the art that the drawings in the following description are merely examples of the disclosure and that other drawings may be derived from them without undue effort. In the drawings:
FIG. 1 is a schematic cross-sectional view of a composite current collector according to some embodiments of the present disclosure;
FIG. 2 is a schematic cross-sectional view of a composite current collector according to other embodiments of the present disclosure;
FIG. 3 is a flow chart of a method of preparing a composite current collector in some embodiments of the present disclosure;
FIG. 4 is an electron micrograph of a composite current collector of example 2 of the present disclosure;
fig. 5 is an electron micrograph of the composite current collector of comparative example 2 of the present disclosure.
Reference numerals in the specific embodiments are as follows:
a composite current collector 10;
a polymer layer 1 and a conductive layer 2.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail below with reference to the accompanying drawings, and it is apparent that the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure.
It should also be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a product or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such product or apparatus. Without further limitation, an element defined by the phrase "comprising" does not exclude the presence of other like elements in a commodity or device comprising such element.
In the description of the embodiments of the present invention, the azimuth or positional relationship indicated by the technical terms "upper", "lower", "thickness", etc. are based on the azimuth or positional relationship shown in the drawings, and are merely for convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the apparatus or element referred to must have a specific azimuth, be configured and operated in a specific azimuth, and thus should not be construed as limiting the embodiments of the present invention.
In the description of the embodiment of the present invention, the symbol "to" means that data of two endpoints before and after "to" and all data between the two endpoints, for example, a to B, means all data of a or more and B or less.
Reference in the present disclosure to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the present disclosure. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Those of skill in the art will explicitly and implicitly appreciate that the embodiments described in this disclosure may be combined with other embodiments.
Composite current collectors have been increasingly studied for their advantages of low cost, high safety, and high energy density. The composite current collector is applied to the lithium ion battery, so that the weight of the lithium ion battery can be reduced, and the safety and the energy density of the lithium ion battery can be improved.
However, the inventors have found through studies that: the existing composite current collector generally adopts a metal film obtained by a traditional PVD mode, and a metal layer is deposited on a polymer in a PVD mode, particularly in a thermal evaporation mode, so that the composite current collector is environment-friendly, easy to realize mass production, high in realizability and basically capable of meeting the requirements of an electric core on material performance. However, PVD deposition is a rapid stack of a large number of metal atoms, which causes a large number of lattice defects, microscopic holes, in the metal film during deposition, resulting in a resistivity of the metal film much higher than 1.5 to 4.0 μΩ·cm of bulk metal. The ion-assisted deposition method can improve the conductivity and the binding force of the composite material, but the traditional ion-assisted deposition method is more appropriate because the energy is uncontrollable and the microstructure which is completely crystallized is broken, so that the defect degree is higher.
In order to solve the technical problems, the method refers to an ion-assisted deposition method, and the composite current collector has better performance by regulating and controlling the film forming energy and the film forming rate of evaporation ions in the deposition process. The method has the advantages that a large number of experiments are conducted, the ideal matching relation among the substrate temperature, the film forming energy, the film forming speed and the ion source beam current is obtained, and therefore the obtained composite current collector has ideal conductivity and bonding force.
The present disclosure provides a composite current collector comprising: the conductive layer is formed on at least one side of the polymer layer by adopting ion beam auxiliary deposition, so that the performance index of the composite current collector meets at least one of the following: the resistivity of the composite current collector is reduced to a first numerical range; the fracture strain of the composite current collector is increased to a second numerical range; the fatigue resistance cycle of the composite current collector is promoted to a third numerical range for a round; the bonding force between the polymer layer and the conductive layer is increased to a fourth value range.
The disclosure also provides a method for preparing the composite current collector, which is characterized by comprising the following steps:
step S1, providing a high polymer layer;
Step S2, depositing a conductive layer on at least one side of the polymer layer by ion beam assisted deposition,
Wherein, the performance index of the composite current collector obtained by the preparation method meets at least one of the following:
The resistivity of the composite current collector is reduced to a first numerical range;
The fracture strain of the composite current collector is increased to a second numerical range;
the fatigue resistance cycle of the composite current collector is promoted to a third numerical range for a round;
the bonding force between the polymer layer and the conductive layer is increased to a fourth value range.
Alternative embodiments of the present disclosure are described in detail below with reference to the drawings.
Referring to fig. 1, an embodiment of the present disclosure provides a composite current collector 10, comprising: the conductive layer 2 is formed on at least one side of the polymer layer 1 by ion beam assisted deposition.
The conductive layer 2 is formed on opposite sides of the polymer layer 1 or on only one side of the polymer layer 1. In this embodiment, the conductive layer 2 is located on the upper and lower surfaces of the polymer layer 1. Referring to fig. 2, in other embodiments, the conductive layer 2 may be located on only one surface of the polymer layer 1.
The conductive layer 2 is formed on at least one side of the polymer layer 1 by ion beam assisted deposition simultaneously with vapor deposition. In this embodiment, the conductive layer 2 is formed on the upper surface of the polymer layer 1 by ion beam assisted deposition while thermally evaporating.
The thickness of the polymer layer 1 is preferably 4.5 to 12. Mu.m. The polymer layer 1 is too thin to play a good supporting role; the polymer layer 1 is excessively thick to increase the volume of the composite current collector 10 and the welding difficulty of the tab in the battery cell manufacturing, so the polymer layer 1 with the thickness in the above range is selected in the disclosure. The material of the polymer layer 1 includes, but is not limited to, at least one of polyethylene terephthalate (PET), polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PEN), poly (p-phenylene terephthamide) (PPTA), polyimide (PI), polycarbonate (PC), polyetheretherketone (PEEK), polyoxymethylene (POM), poly (p-Phenylene Sulfide) (PPs), poly (p-phenylene oxide) (PPO), polyvinyl chloride (PVC), polyamide (PA), or Polytetrafluoroethylene (PTFE). More preferably, when the composite current collector 10 is used as a positive electrode current collector, the polymer layer 1 is a PET film; when the composite current collector 10 is used as a negative electrode current collector, the polymer layer 1 is a PP film. In this example, the polymer layer 1 was a PET film having a thickness of 6. Mu.m. The raw material of the high polymer layer 1 is obviously lower than that of the traditional metal foil, so that the cost of the composite current collector 10 is only about 40-50% of that of the traditional current collector; the density of the high molecular organic material is low, the weight of the composite current collector can be greatly reduced, and the weight energy density of the battery is improved; and because of the existence of the high polymer layer 1, even if the conductive layer 2 is broken down, the short circuit of the battery is not formed, and the safety of the battery is improved.
The material of the conductive layer 2 may be a metal or a carbon conductive material. Metals include, but are not limited to, aluminum, copper, nickel, titanium, silver, nickel-copper alloys, aluminum-zirconium alloys, and the like. Carbon conductive materials include, but are not limited to, carbon nanotubes, graphene, graphite, and the like. Preferably, the material of the conductive layer 2 is metal, and when the composite current collector 10 is a positive current collector, the material of the conductive layer 3 is aluminum or other metal materials that can be used for a positive electrode; when the composite current collector 10 is a negative electrode current collector, the material of the conductive layer 3 is copper or other metal material that can be used for a negative electrode. In this embodiment, the composite current collector 10 is a positive current collector, and the conductive layer 3 is made of metal aluminum.
The thickness of the conductive layer 2 is preferably 0.1 to 2. Mu.m, more preferably 0.5 to 1.5. Mu.m. If the conductive layer 2 is too thin, the resistivity is high due to the oversized effect of the conductive film such as metal, and the internal resistance of the battery cell is affected; if the conductive layer 2 is too thick, the process availability difficulty increases and the cost increases. The resistivity of the conductive layer 2 in the thickness range of the present disclosure is relatively stable, a stable conductive effect can be formed, and one film formation is easy to realize. The thickness of the conductive layer 2 is smaller, and the polymer layer 1 is made of an insulating material, so that the composite current collector 10 has an insulating base material and a light and thin conductive layer structure, when short circuit occurs in a battery, the short circuit current is cut off or reduced in a short time through fusing and the insulating material, the thermal runaway of the battery is effectively prevented, and the safety performance of the battery is improved.
The resistivity of the composite current collector 10 is ρ 1～(ρ1 +3) μΩ·cm, which is substantially close to the resistivity of the bulk conductive material, and the conductivity of the composite current collector 10 is improved. As an example, when the material of the conductive layer 2 is Al, the resistivity of the composite current collector 10 is 2.69 to 5.69 μΩ·cm; when the material of the conductive layer 2 is Cu, the resistivity of the composite current collector 10 is 1.65-4.65 mu omega cm; when the material of the conductive layer 2 is Ni, the resistivity of the composite current collector 10 is 9.6-12.6 mu omega cm; when the material of the conductive layer 2 is Ti, the resistivity of the composite current collector 10 is 4.2-7.2 mu omega cm; when the material of the conductive layer 2 is Au, the resistivity of the composite current collector 10 is 2.4-5.4 mu omega cm; when the material of the conductive layer 3 is Ag, the resistivity of the composite current collector 10 is 1.58 to 4.58 μΩ·cm. In this embodiment, the material of the conductive layer 2 is aluminum, and the resistivity of the composite current collector 10 is 2.73 μΩ·cm, which is substantially close to the resistivity of bulk aluminum.
The fracture strain of the composite current collector 10 is 0-50%, and the composite current collector has good tensile property. The third numerical range of the fatigue resistance cycle of the composite current collector 10 is 100-1000000 under the condition of the strain range of 0.1-5%, and the composite current collector has better fatigue resistance.
The bonding force between the polymer layer 1 and the conductive layer 2 is larger than 5N/15mm, and the bonding force is larger. And the composite current collector after rolling and electrolyte soaking are adopted for testing, the structure of the composite current collector after rolling is complete, the layering phenomenon of a high polymer layer and a metal layer does not occur, and the binding force after rolling is more than 5.88N/15mm.
The composite current collector 10 may be a positive current collector or a negative current collector. In this embodiment, the composite current collector 10 is a positive electrode current collector.
Referring to fig. 3, according to some embodiments of the present disclosure, the present disclosure further provides a method for preparing the composite current collector 10 provided in any one of the above schemes, including the steps of:
step S1, providing the polymer layer 1;
and S2, depositing the conductive layer 2 on at least one side of the high polymer layer 1 by ion beam assisted deposition.
In some embodiments, step S2 comprises the steps of:
Putting the polymer layer 1 into a reaction cavity, and vacuumizing to enable the reaction cavity to form a vacuum environment;
Introducing working gas into the reaction cavity, keeping the vacuum degree of the reaction cavity at 1-4 multiplied by 10 -3 Pa, opening an ion source, and adjusting beam current and energy to generate glow discharge;
The thermal evaporation source is turned on to evaporate the vapor deposition material, and in the glow discharge region, the vapor deposition atoms are accelerated and given higher energy, and finally deposited on the polymer layer 1 to form the conductive layer 2.
In some more preferred embodiments, step S2 comprises the steps of:
Placing the polymer layer 1 into a reaction cavity, and vacuumizing until the vacuum degree of the reaction cavity is higher than 10 -3 Pa;
Introducing working gas into the reaction cavity at a flow rate of 0-30 sccm, keeping the vacuum degree of the cavity at 1-4 multiplied by 10 - 3 Pa, opening an ion source, and keeping the beam energy at 50-200 eV to generate glow discharge, wherein the working gas is Ar gas;
The ion source beam current is 0-500 eV, the thermal evaporation source is turned on to evaporate the evaporation material, the evaporation atoms are accelerated and endowed with higher energy in the glow discharge area, and finally the polymer layer 1 is deposited to form a conductive layer 2.
In this embodiment, the conductive layer 2 is formed on at least one side of the polymer layer 1 by ion beam assisted deposition while thermally evaporating. Preferably, the temperature of the thermal evaporation source is more than or equal to 1300 ℃.
The conductive layer 2 is formed on at least one side of the polymer layer 1 by adopting ion beam auxiliary deposition, the polymer layer 1 is bombarded by adopting high-energy ion beams during deposition, deposited conductive atoms and high-energy ions reach the surface of the polymer layer 1 at the same time, and the deposited atoms obtain energy through ion bombardment, so that the mobility of the deposited atoms is improved, different crystal growth and crystal structures are caused, and the conductivity and interface bonding capability of the composite current collector 10 are further improved. In addition, the ion bombardment releases energy, and the ion bombardment and the electron generate inelastic collision, and the elastic collision and the atom generate the elastic collision, the ion bombardment energy is transferred to the deposited conductive atom, the energy of the conductive atom is improved, some impact atoms with higher energy generate secondary collision, namely cascade collision, the cascade collision causes intense atom movement along the incidence direction of the ion, so that an interface transition region of the film layer atom and the matrix atom is formed, and the concentration value of the film layer atom and the matrix atom in the interface transition region is gradually transited. The energy transfer of ions to membrane atoms is completed by cascade collision, so that the migration capacity and chemical activation capacity of the membrane atoms are increased, the two-phase atomic lattice arrangement is adjusted, and the interface binding force between the polymer layer 1 and the conductive layer 2 is improved; and the conductive layer film with low lattice defect, low microcosmic holes and complete crystallization is obtained by combining the process conditions of ion energy, arrival ratio of ion deposition particles, ion-film-deposition rate, gas content, substrate temperature and the like.
The preparation method of the composite current collector 10 adopts ion-assisted deposition to deposit a conductive layer on the surface of the high polymer layer, so as to obtain the composite current collector 10 with fewer defects and smaller microscopic holes, and the resistivity of the conductive layer 2 is close to that of the corresponding blocky conductive material. And further, the technical problem that the resistivity of the metal thin film is far higher than that of a block metal is caused by a large number of lattice defects and microscopic holes in the metal conductive thin film in the deposition process due to the fact that the conductive layer in the existing composite current collector is rapidly stacked by a large number of metal atoms is solved. In the preparation method of the composite current collector, the high-energy ion bombardment increases the surface roughness of the high polymer layer, so that the adhesive force of the conductive layer 2 on the surface of the high polymer layer 1 is increased; in addition, the ion beam assisted deposition process is a process that physical and chemical effects act simultaneously in the ion implantation process, and physical adsorption and chemical adsorption exist between the conductive layer 2 and the high polymer layer 1, so that the binding force between the conductive layer 2 and the high polymer layer 1 is further improved. The preparation method of the composite current collector can also increase the adhesive force fatigue resistance of the composite current collector under the condition of ensuring the reduction of the resistivity, and solves the technical problems of weak interfacial bonding capability and high resistivity of a high polymer layer and a metal layer in the existing method
The ion beam auxiliary deposition is adopted to prepare the conductive layer during vapor deposition, ion bombardment can increase the kinetic energy of vapor deposition particles, the density of the conductive film layer is improved, the ion bombardment destroys the growth condition of columnar crystals, and the conductive layer is converted into a dense anisotropic structure, so that the conductivity of the conductive layer is improved, and the overall conductivity of the composite current collector is further improved; the ion bombardment in the deposition process forces atoms to be in an unbalanced position, and the high-energy particles bombard the high-molecular layer to enable the surface of the high-molecular layer to generate compressive stress, so that the surface of the high-molecular layer is strengthened, the bonding force of an interface is improved, and the thermal stress and the growth stress of the interface are relieved.
According to some embodiments of the present disclosure, the present disclosure further provides a composite pole piece, including the composite current collector 10 provided in any one of the above schemes or the composite current collector 10 obtained by the preparation method of the composite current collector provided in any one of the schemes.
According to some embodiments of the present disclosure, there is also provided a lithium ion battery comprising the composite pole piece provided in any of the above schemes.
According to some embodiments of the present disclosure, the present disclosure further provides a method for preparing a composite pole piece, including the method for preparing a composite current collector provided in any one of the above schemes.
According to some embodiments of the present disclosure, the present disclosure further provides a method for preparing a lithium ion battery, including the method for manufacturing a composite pole piece provided in any one of the above schemes.
According to some embodiments of the present disclosure, the present disclosure further provides a method for preparing a lithium ion battery, including the method for manufacturing a composite pole piece provided in any one of the above schemes.
The composite current collector 10 and test data provided by the present disclosure are described below by way of specific examples:
Example 1:
in the composite current collector 10 obtained in this example, the polymer layer 1 was a 6 μm PET film, and the conductive layer 2 was a 0.1 μm Al film.
The preparation method comprises the following steps: placing a PET film with the thickness of 6 mu m in a reaction cavity, and introducing working gas Ar into the reaction cavity at a flow rate of 15sccm when the vacuum degree is 2.3X10 -3 Pa; opening an ion source, and enabling the beam current to be 200eV to generate glow discharge; aluminum wires are heated, melted and gasified, the temperature of an evaporation source is more than or equal to 1300 ℃, and Al films with the thickness of 0.1 mu m are respectively deposited on the upper surface and the lower surface of the PET film, so that the composite current collector 10 is obtained.
The composite current collector 10 was tested for breaking strain, fatigue property, resistivity, binding force of 0.1 μm of Al film and PET film before and after rolling, and delamination phenomenon of the PET film and 0.1 μm of Al film after rolling, and cycle number and capacity retention rate corresponding to the battery cell were observed.
Example 2:
in the composite current collector 10 obtained in this example, the polymer layer 1 was a6 μm PET film, and the conductive layer 2 was a1 μm Al film.
The preparation method comprises the following steps: placing a PET film with the thickness of 6 mu m in a reaction cavity, and introducing working gas Ar into the reaction cavity at a flow rate of 15sccm when the vacuum degree is 2.3X10 -3 Pa; opening an ion source, and enabling the beam current to be 200eV to generate glow discharge; aluminum wires are heated, melted and gasified, the temperature of an evaporation source is more than or equal to 1300 ℃, and Al films with the thickness of 1 mu m are respectively deposited on the upper surface and the lower surface of the PET film, so that the composite current collector 10 is obtained.
The composite current collector 10 was tested for breaking strain, fatigue property, resistivity, binding force of the Al film and the PET film of 1 μm before and after rolling, delamination phenomenon of the PET film and Al of 1 μm after rolling, and cycle number and capacity retention rate of the corresponding battery cell.
Example 3:
In the composite current collector 10 obtained in this example, the polymer layer 1 was a6 μm PET film, and the conductive layer 2 was a2 μm Al film.
The preparation method comprises the following steps: placing a PET film with the thickness of 6 mu m in a reaction cavity, and introducing working gas Ar into the reaction cavity at a flow rate of 15sccm when the vacuum degree is 2.3X10 -3 Pa; opening an ion source, and enabling the beam current to be 200eV to generate glow discharge; aluminum wires are heated, melted and gasified, the temperature of an evaporation source is more than or equal to 1300 ℃, and Al films with the thickness of 2 mu m are respectively deposited on the upper surface and the lower surface of the PET film, so that the composite current collector 10 is obtained.
The composite current collector 10 was tested for breaking strain, fatigue property, resistivity, binding force of 2 μm of Al film and PET film before and after rolling, layering phenomenon of PET film and 2 μm of Al after rolling, and cycle number and capacity retention rate of the corresponding battery cell.
Comparative example 1:
this comparative example is substantially the same as example 1, differing only in that: al film of 0.1 μm was deposited on the upper and lower surfaces of the 6 μm PET film by thermal evaporation only, and ion-assisted deposition was not performed during the thermal evaporation.
The preparation method comprises the following steps: and heating the aluminum wire, melting and then gasifying the aluminum wire, wherein the temperature of an evaporation source is more than or equal to 1300 ℃, and respectively depositing Al films with the thickness of 0.1 mu m on the upper surface and the lower surface of the PET film to obtain the composite current collector.
Comparative example 2:
this comparative example is substantially the same as example 2, differing only in that: an Al film of 1 μm was deposited on the upper and lower surfaces of the 6 μm PET film by thermal evaporation only, and ion-assisted deposition was not performed during the thermal evaporation.
The preparation method comprises the following steps: and heating the aluminum wire, melting and then gasifying the aluminum wire, wherein the temperature of an evaporation source is more than or equal to 1300 ℃, and respectively depositing Al films with the thickness of 1 mu m on the upper surface and the lower surface of the PET film to obtain the composite current collector.
Comparative example 3:
This comparative example is substantially identical to example 3, differing only in that: the 2 μm Al film was deposited on the upper and lower surfaces of the 6 μm PET film by thermal evaporation only, and ion-assisted deposition was not performed during the thermal evaporation.
The preparation method comprises the following steps: and heating the aluminum wire, melting and then gasifying the aluminum wire, wherein the temperature of an evaporation source is more than or equal to 1300 ℃, and respectively depositing Al films with the thickness of 2 mu m on the upper surface and the lower surface of the PET film to obtain the composite current collector.
The composite current collectors obtained in examples 1-3 and comparative examples 1-3 were used as positive current collectors to respectively assemble a soft-package lithium ion battery cell for performance test, wherein graphite was used as a negative electrode material, pure copper foil was used as a negative current collector, commercially available conventional lithium hexafluorophosphate electrolyte was used as an electrolyte, a ceramic diaphragm was used as a separator, and 811 ternary nickel, cobalt and manganese materials were used as positive electrode materials.
The tensile properties, fatigue resistance and resistivity of the composite current collector, and the capacity and cycle properties of the prepared lithium ion battery cells were tested for the adhesion and delamination between the polymer layer and the conductive layer of the composite current collector in examples 1 to 3 and comparative examples 1 to 3, respectively, as follows, and the test results are shown in table 1.
1. Resistivity test and strain at break test
The uniaxial tensile test was performed on a SHIMADZU micro-force test system with a constant strain rate of 6.3 x 10 -4s-1. The SHIMADZU micro-force test system is carried with a multimeter of 0-0.003 omega to in-situ measure the resistance of the composite current collector and obtain the fracture strain of the composite current collector.
2. Fatigue Performance test
And testing the fatigue performance of different composite current collectors within the strain range of 0.6%, judging that the composite current collector fails when the resistance change monitored in real time is 10%, and recording the cycle at the moment.
3. Adhesion test
And (3) carrying out rolling and electrolyte soaking tests on the composite current collector, and testing the binding force between the conductive layer and the high polymer layer before and after rolling. And observing whether layering phenomenon exists between the polymer layer and the conductive layer after rolling and electrolyte soaking by adopting an electron microscope.
Specifically, the composite current collector is coated with active material and rolled (roller diameter 300mm, pressure 50-60 tons); then soaking the electrolyte under the following conditions: the conventional lithium hexafluorophosphate electrolyte is soaked for 7 days at 85 ℃.
4. Cell cycle capacity retention test
And (5) carrying out charge and discharge circulation on the prepared battery cell 1C5A, and recording a battery cell circulation ring under the capacity retention rate of 80%.
Table 1: composite current collector parameters and battery performance parameters of each example and comparative example
As can be seen from the results of example 1 versus comparative example 1, example 2 versus comparative example 2, and example 3 versus comparative example 3 in table 1, the present disclosure simultaneously performs ion-assisted deposition during thermal evaporation of the conductive layer, which can reduce the resistivity of the resulting composite current collector, increase the breaking strain and the number of fatigue cycles, increase the bonding force between the PET polymer layer and the metallic Al conductive layer before and after rolling, and improve the cycle performance of the battery cell.
The results of examples 1-3 in table 1 show that, with the same thickness of the polymer layer, the resistivity of the composite current collector decreases, the breaking strain and the number of fatigue cycles increases as the thickness of the deposited conductive layer increases, the bonding force between the PET polymer layer and the metallic Al conductive layer increases before and after rolling, and the cycle performance of the cell increases.
Referring to fig. 4 and 5, which are scanning electron micrographs of the composite current collector of example 2 and comparative example 2 after the roll pressing and the electrolyte soaking, it can be seen from fig. 4 and 5 that there is no delamination between the polymer layer and the conductive layer in example 2 and a partial delamination between the polymer layer and the conductive layer in comparative example 2 after the roll pressing and the electrolyte soaking, respectively. Further, it is explained that the binding force between the polymer layer and the conductive layer in the composite current collector in the embodiment of the present disclosure is higher than that between the polymer layer and the conductive layer in the composite current collector in the comparative example.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present disclosure, and not for limiting the same; although the present disclosure has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some or all of the technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the embodiments of the disclosure, and are intended to be included within the scope of the claims and specification of the present disclosure. In particular, the technical features mentioned in the respective embodiments may be combined in any manner as long as there is no structural conflict. The present disclosure is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.
Claims (10)
1. A composite current collector, comprising: the conductive layer is formed on at least one side of the polymer layer by adopting ion beam auxiliary deposition, so that the performance index of the composite current collector meets at least one of the following:
The resistivity of the composite current collector is reduced to a first numerical range;
The fracture strain of the composite current collector is increased to a second numerical range;
the fatigue resistance cycle of the composite current collector is lifted to a third numerical range for a round;
And the binding force between the high polymer layer and the conductive layer is increased to a fourth numerical range.
2. The composite current collector of claim 1, wherein the first range of values of resistivity of the composite current collector is ρ 1～(ρ1 +3) μΩ -cm, where ρ 1 represents the resistivity of the bulk conductive material corresponding to the conductive material of the conductive layer.
3. The composite current collector of claim 1, wherein the second value of the fracture strain of the composite current collector is in the range of 0 to 50%.
4. The composite current collector of claim 1, wherein the third range of values for fatigue cycles is 100 to 1000000 weeks at a strain ranging from 0.1 to 5%.
5. The composite current collector of claim 1 wherein a fourth range of values for the binding force between the polymeric layer and the conductive layer is greater than 5N/15mm;
optionally, the thickness of the polymer layer is 4.5-12 μm;
optionally, the thickness of the conductive layer is 0.1-2 μm;
optionally, the conductive layer is a metal layer;
Optionally, the conductive layer is formed on at least one side of the polymer layer by ion beam assisted deposition while thermal evaporation;
Optionally, the composite current collector is a positive current collector.
6. A composite pole piece, characterized in that it comprises a composite current collector according to any one of claims 1 to 5.
7. A lithium ion battery comprising the composite pole piece of claim 6.
8. A method for preparing a composite current collector according to any one of claims 1 to 5, comprising the steps of:
step S1, providing the polymer layer;
s2, depositing the conductive layer on at least one side of the high polymer layer by ion beam assisted deposition;
Optionally, in step S2, the conductive layer is formed on at least one side of the polymer layer by ion beam assisted deposition while thermally evaporating;
optionally, step S2 includes the steps of:
placing the polymer layer into a reaction cavity, and vacuumizing to enable the reaction cavity to form a vacuum environment;
Introducing working gas into the reaction cavity, keeping the vacuum degree of the reaction cavity at 1-4 multiplied by 10 -3 Pa, opening an ion source, and adjusting beam current and energy to generate glow discharge;
opening a thermal evaporation source to evaporate evaporation materials, accelerating evaporation atoms in a glow discharge area, giving higher energy, and finally depositing the evaporation atoms on the high polymer layer to form the conductive layer;
optionally, step S2 includes the steps of:
Placing the polymer layer into a reaction cavity, and vacuumizing until the vacuum degree of the reaction cavity is higher than 10 -3 Pa;
Introducing working gas into the reaction cavity at a flow rate of 0-30 sccm, keeping the vacuum degree of the cavity at 1-4 multiplied by 10 -3 Pa, opening an ion source, and keeping the beam energy at 50-200 eV to generate glow discharge, wherein the working gas is Ar gas;
And (3) the ion source beam current is 0-500 eV, a thermal evaporation source is turned on to evaporate the evaporation material, the evaporation atoms are accelerated and endowed with higher energy in a glow discharge area, and finally, a conductive layer is formed on the polymer layer by deposition.
9. A method for preparing a composite pole piece, which is characterized by comprising the preparation method of the composite current collector of claim 8.
10. A method for preparing a lithium ion battery, comprising the preparation method of the composite pole piece of claim 9.
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