Method for preparing lithium battery composite current collector and equipment for preparing lithium battery composite current collector

Abstract

The invention discloses a method for preparing a composite current collector of a lithium battery and equipment (10) for preparing the composite current collector of the lithium battery. The method comprises the following steps: evaporating a first target material to generate first target material vapor; the first target material steam is ionized to form a first ionized structure on the first face of the base film, the first ionized structure comprises at least two ionic layers, and the at least two ionic layers have different ionization rates; and evaporating a second target to form a metal layer including the second target over the first ionized structure.

Description

Method for preparing composite current collector of lithium battery and equipment for preparing composite current collector of lithium battery Technical Field

[0001] The present invention belongs to the field of lithium battery composite current collectors, and in particular relates to a method for preparing a lithium battery composite current collector and equipment for preparing a lithium battery composite current collector. Background Art

[0002] With the continuous growth of the new energy vehicle industry, the demand for lithium-ion batteries has also increased rapidly. As one of the indispensable components of lithium-ion batteries, the current collector can not only carry active substances, but also collect and output the current generated by the active substances of the electrodes. The composite current collector is a composite material that uses raw material films such as PET / PP as the base film and undergoes processes such as vacuum coating to deposit metal atoms on both sides to form a three-layer composite structure of "metal-polymer material-metal". The common vacuum preparation methods currently used are basically magnetron sputtering, evaporation coating, or one or a combination of these. After magnetron sputtering forms a nm-level base layer on the surface, vacuum evaporation and other methods are used to thicken the metal layer. In this process, how to ensure good adhesion between the base film and the coating is the key to the subsequent stable operation of the composite current collector.

[0003] Summary of the Invention

[0004] In view of this, the present application provides a method for preparing a composite current collector for a lithium battery and an apparatus for preparing a composite current collector for a lithium battery to enhance the bonding force between the base film and the subsequent metal layer and improve the stress within the film layer.

[0005] According to an embodiment of the present application, a method for preparing a composite current collector for a lithium battery is provided, the method comprising: evaporating a first target material to generate a first target material vapor; ionizing the first target material vapor to form a first ionization structure on a first surface of a base film, the first ionization structure comprising at least two ion layers, the at least two ion layers respectively having different ionization rates; and evaporating a second target material to form a metal layer comprising the second target material on top of the first ionization structure.

[0006] In some embodiments, ionizing the first target material vapor to form the first ionization structure on the first surface of the base film includes: forming a first ion layer above the first surface of the base film; forming a second ion layer above the first ion layer; and forming a third ion layer above the second ion layer; wherein the ionization rates of the first, second and third ion layers are different.

[0007] In some embodiments, the first, second, and third ion layers have increasing ionization rates.

[0008] In some embodiments, the first, second, and third ion layers have decreasing ionization rates.

[0009] In some embodiments, the ionization rates of the first and third ion layers are less than the ionization rate of the second ion layer.

[0010] In some embodiments, the ionization rates of the first and third ion layers are greater than the ionization rate of the second ion layer.

[0011] In some embodiments, ionizing the first target material vapor to form the first ionization structure on the first surface of the base film also includes: forming a fourth ion layer above the third ion layer; forming a fifth ion layer above the fourth ion layer; and forming a sixth ion layer above the fifth ion layer; wherein the ionization rates of the fourth, fifth and sixth ion layers are different.

[0012] In some embodiments, the ionization rates of the fourth, fifth, and sixth ion layers increase.

[0013] In some embodiments, the ionization rates of the fourth, fifth, and sixth ion layers decrease.

[0014] In some embodiments, the ionization rates of the fourth and sixth ion layers are lower than the ionization rate of the fifth ion layer.

[0015] In some embodiments, the ionization rates of the fourth and sixth ion layers are greater than the ionization rate of the fifth ion layer.

[0016] In some embodiments, the method also includes: evaporating a third target material to generate a third target material vapor; ionizing the third target material vapor to form a second ionization structure on the second surface of the base film, wherein the second surface is opposite to the first surface, and the second ionization structure includes at least two ion layers, and the at least two ion layers have different ionization rates respectively; and evaporating the second target material to form a metal layer including the second target material on the second ionization structure.

[0017] In some embodiments, forming the second ionization structure on the second surface of the base membrane includes: forming a seventh ion layer above the second surface of the base membrane; forming an eighth ion layer above the seventh ion layer; and forming a ninth ion layer above the eighth ion layer; wherein the ionization rates of the seventh, eighth and ninth ion layers are different.

[0018] In some embodiments, the ionization rates of the seventh, eighth, and ninth ion layers increase.

[0019] In some embodiments, the ionization rates of the seventh, eighth, and ninth ion layers decrease.

[0020] In some embodiments, the ionization rates of the seventh and ninth ion layers are lower than the ionization rate of the eighth ion layer.

[0021] In some embodiments, the ionization rates of the seventh and ninth ion layers are greater than the ionization rate of the eighth ion layer.

[0022] In some embodiments, forming the second ionization structure on the second surface of the base membrane also includes: forming a tenth ion layer above the ninth ion layer; forming an eleventh ion layer above the tenth ion layer; and forming a twelfth ion layer above the eleventh ion layer; wherein the ionization rates of the tenth, eleventh and twelfth ion layers are different.

[0023] In some embodiments, the ionization rates of the tenth, eleventh, and twelfth ion layers increase.

[0024] In some embodiments, the ionization rates of the tenth, eleventh, and twelfth ion layers decrease.

[0025] In some embodiments, the ionization rates of the tenth and twelfth ion layers are lower than the ionization rate of the eleventh ion layer.

[0026] In some embodiments, the ionization rates of the tenth and twelfth ion layers are greater than the ionization rate of the eleventh ion layer.

[0027] In some embodiments, the first, second, and third targets are identical, partially identical, or different.

[0028] In some embodiments, the first target material comprises aluminum oxide, and the third target material comprises aluminum.

[0029] In some embodiments, the base film includes any one of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyethylene, polypropylene, polyvinyl chloride, polyvinylidene fluoride, polytetrafluoroethylene, polyphenylene sulfide, polyphenylene oxide, polyacrylonitrile, cellulose acetate, polystyrene or polyimide, or a mixture thereof.

[0030] In some embodiments, the first ionized structure includes at least one of aluminum, copper, nickel, tin, zinc, chromium, iron, lithium, cobalt, and oxides or alloys thereof, or includes at least one of silicon oxide, silicon carbide, silicon nitride, graphite, carbon nanotubes, and carbon fibers.

[0031] In some embodiments, the thickness of the first ionization structure is less than 1000 nm.

[0032] In certain embodiments, the metal layer includes at least one of aluminum, copper, lithium, and oxides or alloys thereof.

[0033] In some embodiments, the thickness of the metal layer is less than 50 μm.

[0034] According to an embodiment of the present application, a device for preparing a composite current collector for a lithium battery is provided, wherein the device is configured to perform the above-mentioned method. The device comprises: a conveying component, an evaporation component, and an ionization device. The conveying component is used to convey a base film; the evaporation component is disposed below the conveying component. The evaporation component is configured to evaporate a target material. The ionization device is disposed above the evaporation component. The ionization device is configured to ionize the vapor of the target material to form at least two ion layers on the base film, wherein the at least two ion layers have different ionization rates. The conveying component comprises a conveying roller. The conveying roller is configured to carry the base film so that the base film to be coated faces the evaporation component and the ionization device. The conveying roller comprises a cooling component. The cooling component is configured to control the temperature of the base film during coating to prevent the base film from overheating, shrinking, and deforming due to the formation of the at least two ion layers with different ionization rates.

[0035] The present invention adjusts the ionization rate during the evaporation process to form an intermediate layer group between the outer metal layer and the base film layer, strengthening the bonding strength between the base film and subsequent metal layers and improving the internal stress of the film layer. During the ionization rate adjustment process, the temperature inside the vacuum chamber also changes accordingly. Combined with a conveyor roller equipped with a cooling component, this ensures that the base film will not continuously overheat and deform during the cyclic coating process. Furthermore, the film group structure formed by different ionization rates is more uniform and dense than the composite current collector structure formed by evaporation alone. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The accompanying drawings are used to provide a further understanding of the present application and constitute a part of the specification. Together with the following detailed description, they are used to explain the present application but do not constitute a limitation of the present application. In the accompanying drawings:

[0037] FIG1 is a schematic diagram illustrating an apparatus for preparing a composite current collector for a lithium battery according to an embodiment of the present application.

[0038] FIG2 illustrates the process steps of a method for preparing a composite current collector for a lithium battery according to an embodiment of the present application.

[0039] FIG3 illustrates a schematic diagram of a structure formed on the first surface of the base film according to an embodiment of the present application.

[0040] FIG. 4A is a schematic structural diagram illustrating a first ionization structure formed by performing one cycle according to an embodiment of the present application.

[0041] FIG. 4B is a schematic structural diagram illustrating a second cycle to form a first ionized structure according to an embodiment of the present application.

[0042] FIG5 illustrates the process steps of a method for preparing a composite current collector for a lithium battery according to an embodiment of the present application.

[0043] FIG6 illustrates a schematic diagram of a structure formed on the second surface of the base film according to an embodiment of the present application.

[0044] FIG. 7A is a schematic structural diagram illustrating a second ionization structure formed by performing one cycle according to an embodiment of the present application.

[0045] FIG. 7B is a schematic structural diagram illustrating a second cycle to form a second ionization structure according to an embodiment of the present application. DETAILED DESCRIPTION

[0046] The following disclosure provides a variety of implementations or illustrations that can be used to implement different features of the present disclosure. The specific examples of components and configurations described below are intended to simplify the present disclosure. As will be appreciated, these descriptions are illustrative only and are not intended to limit the present disclosure. For example, in the description below, forming a first feature on or above a second feature may include certain embodiments in which the first and second features are in direct contact with each other; and may also include certain embodiments in which additional components are formed between the first and second features, such that the first and second features may not be in direct contact. In addition, the present disclosure may reuse component symbols and / or labels in multiple embodiments. Such repetition is for the purposes of brevity and clarity and does not, in itself, represent a relationship between the different embodiments and / or configurations discussed.

[0047] Furthermore, spatially relative terms such as "below," "beneath," "below," "above," and the like may be used herein to facilitate description of the relationship of one component or feature depicted in a figure relative to one or more other components or features. These spatially relative terms are intended to encompass various orientations of the device during use or operation, in addition to the orientation depicted in the figures. The device may be placed in other orientations (e.g., rotated 90 degrees or in other orientations), and these spatially relative descriptive terms should be interpreted accordingly.

[0048] Although the numerical ranges and parameters used to define the broader scope of this application are approximate, the numerical values ​​of the specific examples have been presented herein as precisely as possible. However, any numerical value inherently and inevitably contains standard deviations resulting from individual testing methods. As used herein, "about" generally means that the actual value is within plus or minus 10%, 5%, 1%, or 0.5% of a specified value or range. Alternatively, the term "about" means that the actual value falls within an acceptable standard error of the mean, as determined by one of ordinary skill in the art. It should be understood that, except in the experimental examples, or unless otherwise expressly indicated, all ranges, amounts, values, and percentages used herein (e.g., to describe material amounts, time periods, temperatures, operating conditions, quantitative ratios, and the like) are modified by the word "about." Therefore, unless otherwise indicated, the numerical parameters disclosed in this specification and the appended claims are approximate and may be modified as needed. At a minimum, these numerical parameters should be understood to include the number of significant digits indicated and to apply normal rounding. Herein, numerical ranges are expressed from one endpoint to another endpoint or between two endpoints; unless otherwise stated, the numerical ranges described herein include the endpoints.

[0049] Figure 1 illustrates a schematic diagram of an apparatus 10 for preparing a composite current collector for a lithium battery according to an embodiment of the present application. In certain embodiments, the apparatus 10 can coat both sides of a base film XM individually or simultaneously. The apparatus 10 includes a conveying assembly 11, an evaporation assembly 12, and ionization devices 13 and 13'.

[0050] The conveyor assembly 11 is used to convey the base film XM. In certain embodiments, the conveyor assembly 11 includes an unwinding roller 111, conveying rollers 112 and 112', a transition roller 113, and a take-up roller 114. After being unwound by the unwinding roller 111, the base film XM is sequentially guided by the conveying roller 112, the transition roller 113, and the conveying roller 112' before being finally taken up by the take-up roller 114. In certain embodiments, a cooling component LD is provided in the conveying rollers 112 and 112'. The cooling component LD is configured to control the temperature of the base film XM during coating to prevent the base film XM from overheating, shrinking, or deforming due to the formation of ion layers with different ionization rates.

[0051] The evaporation assembly 12 is disposed below the conveyor assembly 11. The evaporation assembly 12 is configured to evaporate the target material to generate vapor comprising target material components. In certain embodiments, the evaporation assembly 12 includes crucibles 121 and 121' for holding the target material. In certain embodiments, the evaporation assembly 12 also includes a target material transport device and a heating device (not shown). The target material transport device is configured to transport the target material into the crucibles 121 and 121'. The heating device may be, for example, but not limited to, an electron gun to evaporate the target material in the crucibles 121 and 121'.

[0052] It should be noted that the present application does not limit the specific implementation of the heating device, as long as the target material can be evaporated to generate steam, it should fall within the scope of the present application. In some embodiments, the minimum distance between the crucibles 121 and 121 ′ and the base film XM is controlled to be 200 mm.

[0053] The ionization devices 13 and 13' are positioned directly above the evaporation assembly 12. Specifically, the ionization device 13 corresponds to the crucible 121 and the conveyor roller 112. The side of the base film XM carried by the conveyor roller 112 that faces the ionization device 13 and the crucible 121 will be coated. Furthermore, the ionization device 13' corresponds to the crucible 121' and the conveyor roller 112'. The side of the base film XM carried by the conveyor roller 112' that faces the ionization device 13' and the crucible 121' will be coated.

[0054] The ionization devices 13 and 13' are configured to ionize the target vapor in the crucibles 121 and 121', respectively, thereby forming ion layers on both sides of the base film XM. In certain embodiments, the ionization devices 13 and 13' may be configured as a ring-shaped tungsten filament structure or a spiral tungsten filament structure. In certain embodiments, when the evaporation components 12 and 12' are at their longest point L, the diameter of the ionization devices 13 and 13' is d, and the distance h between the ionization devices 13 and 13' and the evaporation components 12 and 12', respectively, satisfies the following relationship: L < d ≤ (L + 2h).

[0055] In certain embodiments, apparatus 10 further includes a control device 14 configured to control the ionization rate of target vapor ionization by ionization devices 13 and 13'. The ionization rate γ is the ratio of ionized atoms to all evaporated atoms (0 ≤ γ ≤ 1). The ionization rate γ directly affects the hardness and corrosion resistance of the coating. A higher ionization rate results in a denser coating and better bonding strength.

[0056] In some embodiments, the base film XM is a polymer base film comprising any one of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyethylene, polypropylene, polyvinyl chloride, polyvinylidene fluoride, polytetrafluoroethylene, polyphenylene sulfide, polyphenylene oxide, polyacrylonitrile, cellulose acetate, polystyrene, or polyimide, or a mixture thereof. In some embodiments, the base film XM has a thickness of 0 to 50 μm.

[0057] Figure 2 demonstrates the process steps of a method 20 for preparing a composite current collector for a lithium battery according to an embodiment of the present application. In some embodiments, the device 10 shown in Figure 1 can be used to perform the process steps of method 20. Provided that similar results can be obtained in principle, the present application is not limited to performing the process steps entirely in accordance with the process steps shown in Figure 2. Method 20 may include steps 21, 22, and 23. In step 21, the first target material may be evaporated to produce a first target material vapor. In step 22, the first target material vapor may be ionized to form a first ionization structure on the first surface of the base film. The first ionization structure may include at least two ion layers, each having a different ionization rate. In step 23, the second target material may be evaporated to form a metal layer including the second target material on the first ionization structure.

[0058] Referring simultaneously to Figures 1, 2, and 3, Figure 3 illustrates a schematic diagram of a structure formed on the first surface s1 of the base film XM according to one embodiment of the present application. In the process illustrated in method 20, a first target material is placed in a crucible 121 and evaporated by a heating device (such as, but not limited to, an electron gun) to generate vapor. In certain embodiments, the evaporation assembly 12 can evaporate the first target material at a deposition power of 150 kW.

[0059] Next, the transport assembly 11 begins transporting the base film XM. In some embodiments, the transport assembly 11 can transport the base film XM at a speed of 10 m / min. Simultaneously, the ionization device 13 ionizes the vapor. The ionized vapor forms a first ion layer Y1 on the first surface s1 of the base film XM. Subsequently, the ionized vapor can continue to form a second ion layer Y2 through an nth ion layer Yn on the first surface s1 of the base film XM, thereby forming a first ionized structure YS. The ionization rate of the ionization device 13 is controlled by the control device 14, and the ion layers Y1 through Yn can have completely or partially different ionization rates.

[0060] In some embodiments, the control device 14 can automatically adjust the ionization rate of the ionization device 13 once per minute, with each ion layer having a thickness of approximately 5 nm. After the first ionization structure YS is completed, the control device 14 shuts down the ionization device 13. In some embodiments, the first ionization structure YS comprises at least one of aluminum, copper, nickel, tin, zinc, chromium, iron, lithium, cobalt, and oxides or alloys thereof, or at least one of silicon oxide, silicon carbide, silicon nitride, graphite, carbon nanotubes, and carbon fibers. In some embodiments, the thickness of the first ionization structure YS is less than 1000 nm.

[0061] Finally, the second target material is placed in the crucible 121 and evaporated by a heating device (such as but not limited to an electron gun) to generate vapor. In some embodiments, the evaporation component 12 can evaporate the second target material at an evaporation power of 150Kw. At the same time, the conveying component 11 synchronously transports the base film XM. In some embodiments, the conveying component 11 transports the base film XM at a speed of 20m / min. The vapor of the second target material forms a metal layer Z including the second target material on the first ionization structure YS. In this way, the coating of the first surface s1 of the base film XM can be completed. In some embodiments, the thickness of the metal layer Z is less than 50μm. In some embodiments, the thickness of the metal layer Z is about 1μm. In some embodiments, the metal layer Z includes at least one of aluminum, copper, lithium and its oxides or alloys.

[0062] In some embodiments, a stack of three ion layers can be used as a single cycle to form the first ionized structure YS. When performing the first cycle, the first ionized structure YS includes three ion layers; when performing the second cycle, the first ionized structure YS includes six ion layers, and so on. When performing the first cycle, step 22 may specifically include: the control device 14 controls the ionization device 13 to ionize the vapor of the first target material at a first ionization rate to form a first ion layer Y1 on the first surface s1 of the base film XM; then, the control device 14 controls the ionization device 13 to ionize the vapor of the first target material at a second ionization rate to form a second ion layer Y2 on the first ion layer Y1; finally, the control device 14 controls the ionization device 13 to ionize the vapor of the first target material at a third ionization rate to form a third ion layer Y3 on the second ion layer Y2. In some embodiments, the first, second, and third ionization rates are different.

[0063] However, the present application does not limit the number of ion layers included in the first ionization structure YS to three layers. In other embodiments, the first ionization structure YS may include only other numbers of ion layers, and the ionization rates of the ion layers may be completely or partially different.

[0064] 4A , which illustrates a schematic diagram of a first ionization structure YS formed by performing one cycle according to an embodiment of the present application, wherein the first ionization structure YS includes a first ion layer Y1 , a second ion layer Y2 , and a third ion layer Y3 .

[0065] In some embodiments, the first ionization rate, the second ionization rate, and the third ionization rate of the first ionization layer Y1, the second ionization layer Y2, and the third ionization layer Y3 increase in sequence. In some embodiments, the first ionization rate of the first ionization layer Y1 is 40%, the second ionization rate of the second ionization layer Y2 is 60%, and the third ionization rate of the third ionization layer Y3 is 80%.

[0066] In some embodiments, the first ionization rate, the second ionization rate, and the third ionization rate of the first ionization layer Y1, the second ionization layer Y2, and the third ionization layer Y3 decrease in a descending order. In some embodiments, the first ionization rate of the first ionization layer Y1 is 80%, the second ionization rate of the second ionization layer Y2 is 60%, and the third ionization rate of the third ionization layer Y3 is 40%.

[0067] In some embodiments, the first ionization rate of the first ion layer Y1 and the third ionization rate of the third ion layer Y3 are less than the second ionization rate of the second ion layer Y2. In some embodiments, the first ionization rate of the first ion layer Y1 is 40%, the second ionization rate of the second ion layer Y2 is 80%, and the third ionization rate of the third ion layer Y3 is 60%. In some embodiments, the first ionization rate of the first ion layer Y1 is 60%, the second ionization rate of the second ion layer Y2 is 80%, and the third ionization rate of the third ion layer Y3 is 40%.

[0068] In some embodiments, the first ionization rate of the first ion layer Y1 and the third ionization rate of the third ion layer Y3 are greater than the second ionization rate of the second ion layer Y2. In some embodiments, the first ionization rate of the first ion layer Y1 is 80%, the second ionization rate of the second ion layer Y2 is 40%, and the third ionization rate of the third ion layer Y3 is 60%. In some embodiments, the first ionization rate of the first ion layer Y1 is 60%, the second ionization rate of the second ion layer Y2 is 40%, and the third ionization rate of the third ion layer Y3 is 80%.

[0069] It should be noted that the specific numbers of the first ionization rate, the second ionization rate, and the third ionization rate are merely examples and are not limitations of the present application.

[0070] When performing the second cycle, step 22 may further include: the control device 14 controls the ionization device 13 to ionize the vapor of the first target material at a fourth ionization rate to form a fourth ionization layer Y4 above the third ionization layer Y3; then, the control device 14 controls the ionization device 13 to ionize the vapor of the first target material at a fifth ionization rate to form a fifth ionization layer Y5 above the fourth ionization layer Y4; and finally, the control device 14 controls the ionization device 13 to ionize the vapor of the first target material at a sixth ionization rate to form a sixth ionization layer Y6 above the fifth ionization layer Y5. In some embodiments, the fourth, fifth, and sixth ionization rates are different.

[0071] Referring to FIG4B , FIG4B illustrates a schematic diagram of a structure of a first ionization structure YS formed by performing a secondary cycle according to an embodiment of the present application. In the embodiment of FIG4B , the first ionization structure YS includes, in addition to the first ion layer Y1, the second ion layer Y2, and the third ion layer Y3 of the embodiment of FIG4A , a fourth ion layer Y4, a fifth ion layer Y5, and a sixth ion layer Y6.

[0072] In some embodiments, the fourth ionization rate, the fifth ionization rate, and the sixth ionization rate of the fourth ionization layer Y4, the fifth ionization layer Y5, and the sixth ionization layer Y6 are increased. In some embodiments, the fourth ionization rate of the fourth ionization layer Y4 is 40%, the fifth ionization rate of the fifth ionization layer Y5 is 60%, and the sixth ionization rate of the sixth ionization layer Y6 is 80%.

[0073] In some embodiments, the fourth ionization rate, the fifth ionization rate, and the sixth ionization rate of the fourth ionization layer Y4, the fifth ionization layer Y5, and the sixth ionization layer Y6 decrease in a descending order. In some embodiments, the fourth ionization rate of the fourth ionization layer Y4 is 80%, the fifth ionization rate of the fifth ionization layer Y5 is 60%, and the sixth ionization rate of the sixth ionization layer Y6 is 40%.

[0074] In some embodiments, the fourth ionization rate of the fourth ion layer Y4 and the sixth ionization rate of the sixth ion layer Y6 are less than the fifth ionization rate of the fifth ion layer Y5. In some embodiments, the fourth ionization rate of the fourth ion layer Y4 is 40%, the fifth ionization rate of the fifth ion layer Y5 is 80%, and the sixth ionization rate of the sixth ion layer Y6 is 60%. In some embodiments, the fourth ionization rate of the fourth ion layer Y4 is 60%, the fifth ionization rate of the fifth ion layer Y5 is 80%, and the sixth ionization rate of the sixth ion layer Y6 is 40%.

[0075] In some embodiments, the fourth ionization rate of the fourth ion layer Y4 and the sixth ionization rate of the sixth ion layer Y6 are greater than the fifth ionization rate of the fifth ion layer Y5. In some embodiments, the fourth ionization rate of the fourth ion layer Y4 is 80%, the fifth ionization rate of the fifth ion layer Y5 is 40%, and the sixth ionization rate of the sixth ion layer Y6 is 60%. In some embodiments, the fourth ionization rate of the fourth ion layer Y4 is 60%, the fifth ionization rate of the fifth ion layer Y5 is 40%, and the sixth ionization rate of the sixth ion layer Y6 is 80%.

[0076] Likewise, the specific numbers of the fourth ionization rate, the fifth ionization rate, and the sixth ionization rate are merely examples and are not limitations of the present application.

[0077] It should be noted that the present application does not limit the target material used in the first cycle to be the same as the target material used in the second cycle.

[0078] The embodiments of Figures 2, 3, 4A and 4B describe an embodiment of forming a first ionization structure YS on the first surface s1 of the base film XM. The first target material is carried by the crucible 121 of the evaporation component 12, and the first target material is evaporated by the heating device of the evaporation component 12 to generate vapor. The vapor is then ionized by the ionization device 13 and ion layers with different ionization rates are formed on the first surface s1 of the base film XM, thereby forming the first ionization structure YS.

[0079] The specific structure formed on the second surface s2 of the base film XM in the embodiments of Figures 2, 3, 4A, and 4B is not limited. In some embodiments, the second surface s2 of the base film XM can have the same, partially the same, or completely different structure as the first surface s1. As described in the embodiment of Figure 1, the crucibles 121 and 121' of the evaporation assembly 12 and the ionization devices 13 and 13' can be used to deposit films on the first surface s1 and the second surface s2 of the base film XM separately or simultaneously.

[0080] Referring to Figure 5 , Figure 5 illustrates the process steps of method 30 for preparing a composite current collector for a lithium battery according to an embodiment of the present application. In certain embodiments, the apparatus 10 shown in Figure 1 can be used to perform the process steps of method 30. This application does not limit the order in which method 30 and method 20 are performed. In certain embodiments, method 20 can be performed first, followed by method 30, or vice versa. In certain embodiments, method 20 and method 30 can also be performed simultaneously. This application is not limited to performing the process steps shown in Figure 5 , provided that similar results can be achieved. Method 30 may include steps 21', 22', and 23'. In step 21', a third target material may be evaporated to produce a third target material vapor. In step 22', the third target material vapor may be ionized to form a second ionized structure on the second surface of the base film. The second ionized structure may include at least two ion layers, each having a different ionization rate. In step 23', the second target material may be evaporated to form a metal layer comprising the second target material on the second ionized structure.

[0081] With reference to Figures 1, 5, and 6 simultaneously, Figure 6 illustrates a schematic diagram of a structure formed on the second surface s2 of the base film XM according to an embodiment of the present application. In some embodiments, the first target material and the third target material may be the same, such that the first ionization structure YS and the second ionization structure YS' have the same composition. In some embodiments, the first target material and the third target material may be different, such that the first ionization structure YS and the second ionization structure YS' have different compositions. In some embodiments, the first target material includes aluminum oxide and the third target material includes aluminum, such that the first ionization structure YS and the second ionization structure YS' have different compositions.

[0082] In the process shown in method 30, the third target material is placed in the crucible 121' and evaporated by a heating device (such as but not limited to an electron gun) to generate vapor of the third target material. In some embodiments, the evaporation assembly 12 can evaporate the third target material at an evaporation power of 150KW.

[0083] Next, the transport assembly 11 begins to transport the base film XM. In some embodiments, the transport assembly 11 can transport the base film XM at a speed of 10 m / min. At the same time, the ionization device 13' ionizes the third target material vapor respectively. The vapor after the ionization of the third target material forms the seventh ion layer Y1' on the second surface s2 of the base film XM. Then, the vapor after the ionization of the third target material can continue to form the eighth ion layer Y2' to the n'th ion layer Yn' on the second surface s2 of the base film XM to form a second ionization structure YS'. The ionization rate of 13' is controlled by the control device 14, and the ion layers Y1' to Yn' can have completely or partially different ionization rates.

[0084] In some embodiments, the control device 14 can automatically adjust the ionization rate of the ionization device 13' once per minute, with the thickness of each ion layer being approximately 5 nm. After completing the second ionization structure YS', the control device 14 shuts down the ionization device 13'. In some embodiments, the second ionization structure YS' comprises at least one of aluminum, copper, nickel, tin, zinc, chromium, iron, lithium, cobalt, and oxides or alloys thereof, or at least one of silicon oxide, silicon carbide, silicon nitride, graphite, carbon nanotubes, and carbon fibers. In some embodiments, the thickness of the second ionization structure YS' is less than 1000 nm.

[0085] Finally, the second target material is placed in the crucible 121' and evaporated by a heating device (such as but not limited to an electron gun) to generate vapor. In some embodiments, the evaporation component 12 can evaporate the second target material at an evaporation power of 150Kw. At the same time, the conveying component 11 synchronously transports the base film XM. In some embodiments, the conveying component 11 transports the base film XM at a speed of 20m / min. The vapor of the second target material forms a metal layer Z' including the second target material on the second ionization structure YS'. In this way, the coating of the second surface s2 of the base film XM can be completed. In some embodiments, the thickness of the metal layer Z' is less than 50μm. In some embodiments, the thickness of the metal layer Z' is about 1μm. In some embodiments, the metal layer Z' includes at least one of aluminum, copper, lithium and its oxides or alloys.

[0086] In some embodiments, the second ionization structure YS' can be formed by stacking three ion layers as a single cycle. When performing one cycle, the second ionization structure YS' includes three ion layers; when performing two cycles, the second ionization structure YS' includes six ion layers, and so on. When performing one cycle, step 22' may specifically include: the control device 14 controls the ionization device 13' to ionize the vapor of the third target material at a seventh ionization rate to form a seventh ion layer Y1' on the second surface s2 of the base film XM; then, the control device 14 controls the ionization device 13' to ionize the vapor of the third target material at an eighth ionization rate to form an eighth ion layer Y2' on the seventh ion layer Y1'; finally, the control device 14 controls the ionization device 13' to ionize the vapor of the third target material at a ninth ionization rate to form a ninth ion layer Y3' on the eighth ion layer Y2'. In some embodiments, the seventh, eighth, and ninth ionization rates are different from each other.

[0087] 7A shows a schematic diagram of a second ionization structure YS' formed by performing one cycle according to an embodiment of the present application. In the embodiment of FIG7A , the second ionization structure YS' includes a seventh ion layer Y1', an eighth ion layer Y2', and a ninth ion layer Y3'.

[0088] In some embodiments, the seventh ionization rate, the eighth ionization rate, and the ninth ionization rate of the seventh ionization layer Y1', the eighth ionization layer Y2', and the ninth ionization layer Y3' increase in sequence. In some embodiments, the seventh ionization rate of the seventh ionization layer Y1' is 40%, the eighth ionization rate of the eighth ionization layer Y2' is 60%, and the ninth ionization rate of the ninth ionization layer Y3' is 80%.

[0089] In some embodiments, the seventh ionization rate, the eighth ionization rate, and the ninth ionization rate of the seventh ionization layer Y1', the eighth ionization layer Y2', and the ninth ionization layer Y3' decrease in a descending order. In some embodiments, the seventh ionization rate of the seventh ionization layer Y1' is 80%, the eighth ionization rate of the eighth ionization layer Y2' is 60%, and the ninth ionization rate of the ninth ionization layer Y3' is 40%.

[0090] In some embodiments, the seventh ionization rate of the seventh ion layer Y1' and the ninth ionization rate of the ninth ion layer Y3' are less than the eighth ionization rate of the eighth ion layer Y2'. In some embodiments, the seventh ionization rate of the seventh ion layer Y1' is 40%, the eighth ionization rate of the eighth ion layer Y2' is 80%, and the ninth ionization rate of the ninth ion layer Y3' is 60%. In some embodiments, the seventh ionization rate of the seventh ion layer Y1' is 60%, the eighth ionization rate of the eighth ion layer Y2' is 80%, and the ninth ionization rate of the ninth ion layer Y3' is 40%.

[0091] In some embodiments, the seventh ionization rate of the seventh ion layer Y1' and the ninth ionization rate of the ninth ion layer Y3' are greater than the eighth ionization rate of the eighth ion layer Y2'. In some embodiments, the seventh ionization rate of the seventh ion layer Y1' is 80%, the eighth ionization rate of the eighth ion layer Y2' is 40%, and the ninth ionization rate of the ninth ion layer Y3' is 60%. In some embodiments, the seventh ionization rate of the seventh ion layer Y1' is 60%, the eighth ionization rate of the eighth ion layer Y2' is 40%, and the ninth ionization rate of the ninth ion layer Y3' is 80%.

[0092] It should be noted that the specific numbers of the seventh ionization rate, the eighth ionization rate, and the ninth ionization rate are merely examples and are not limitations of the present application.

[0093] When performing the second cycle, step 22' may further include: the control device 14 controls the ionization device 13' to ionize the vapor of the third target material at a tenth ionization rate to form a tenth ionization layer Y4' above the ninth ionization layer Y3'; then, the control device 14 controls the ionization device 13' to ionize the vapor of the third target material at an eleventh ionization rate to form an eleventh ionization layer Y5' above the tenth ionization layer Y4'; and finally, the control device 14 controls the ionization device 13' to ionize the vapor of the third target material at a twelfth ionization rate to form a twelfth ionization layer Y6' above the eleventh ionization layer Y5'. In some embodiments, the tenth, eleventh, and twelfth ionization rates are different from each other.

[0094] Referring to FIG. 7B , FIG. 7B illustrates a schematic diagram of a second ionization structure YS' formed by performing a secondary cycle according to an embodiment of the present application. In the embodiment of FIG. 7B , the second ionization structure YS' includes, in addition to the seventh ionization layer Y1', the eighth ionization layer Y2', and the ninth ionization layer Y3' of the embodiment of FIG. 7A , a tenth ionization layer Y4', an eleventh ionization layer Y5', and a twelfth ionization layer Y6'.

[0095] In some embodiments, the tenth ionization rate of the tenth ion layer Y4', the eleventh ionization rate of the eleventh ion layer Y5', and the twelfth ionization rate of the twelfth ion layer Y6' are increased. In some embodiments, the tenth ionization rate of the tenth ion layer Y4' is 40%, the eleventh ionization rate of the eleventh ion layer Y5' is 60%, and the twelfth ionization rate of the twelfth ion layer Y6' is 80%.

[0096] In some embodiments, the tenth ionization rate of the tenth ion layer Y4', the eleventh ionization rate of the eleventh ion layer Y5', and the twelfth ionization rate of the twelfth ion layer Y6' decreases. In some embodiments, the tenth ionization rate of the tenth ion layer Y4' is 80%, the eleventh ionization rate of the eleventh ion layer Y5' is 60%, and the twelfth ionization rate of the twelfth ion layer Y6' is 40%.

[0097] In some embodiments, the tenth ionization rate of the tenth ion layer Y4' and the twelfth ionization rate of the twelfth ion layer Y6' are less than the eleventh ionization rate of the eleventh ion layer Y5'. In some embodiments, the tenth ionization rate of the tenth ion layer Y4' is 40%, the eleventh ionization rate of the eleventh ion layer Y5' is 80%, and the twelfth ionization rate of the twelfth ion layer Y6' is 60%. In some embodiments, the tenth ionization rate of the tenth ion layer Y4' is 60%, the eleventh ionization rate of the eleventh ion layer Y5' is 80%, and the twelfth ionization rate of the twelfth ion layer Y6' is 40%.

[0098] In some embodiments, the tenth ionization rate of the tenth ion layer Y4' and the twelfth ionization rate of the twelfth ion layer Y6' are greater than the eleventh ionization rate of the eleventh ion layer Y5'. In some embodiments, the tenth ionization rate of the tenth ion layer Y4' is 80%, the eleventh ionization rate of the eleventh ion layer Y5' is 40%, and the twelfth ionization rate of the twelfth ion layer Y6' is 60%. In some embodiments, the tenth ionization rate of the tenth ion layer Y4' is 60%, the eleventh ionization rate of the eleventh ion layer Y5' is 40%, and the twelfth ionization rate of the twelfth ion layer Y6' is 80%.

[0099] Likewise, the specific numbers of the tenth, eleventh, and twelfth ionization ratios are merely examples and are not limitations of the present application.

[0100] It should be noted that the present application does not limit the target material used in the first cycle to be the same as the target material used in the second cycle.

[0101] Those skilled in the art will appreciate that coating of the first and second surfaces s1 and s2 of the base film XM can be achieved by combining any one of the first ionization structures YS in the embodiments of FIG. 4A and FIG. 4B and any one of the second ionization structures YS′ in the embodiments of FIG. 7A and FIG. 7B .

[0102] In some embodiments, the base film XM may be subjected to a plasma pretreatment before executing methods 20 and 30. Specifically, a plasma is generated by discharging a reactive gas (such as, but not limited to, Ar, O2, or N2). The plasma contains high-energy substances such as electrons, ions, free radicals, and ultraviolet rays. The plasma acts on the base film XM, and the active particles and high-energy rays contained therein react and collide with organic pollutant molecules on the surface of the base film XM to form small volatile molecules, which are then removed from the surface, achieving a cleaning effect and activating the surface.

[0103] The applicant conducted a series of experiments to verify the relationship between different ionization rates and peel and tensile strengths for the first ionized structure YS and the second ionized structure YS', each composed of ion layers with different ionization rates. Peel strength testing was conducted in accordance with GB / T 2792-2014, Test Method for Peel Strength of Adhesive Tapes, and tensile strength testing was performed using a universal tensile testing machine in accordance with GB / T 5230-2020, Electrolytic Copper Foil for Printed Circuit Boards. The experimental results are listed in Table 1 below.

[0104] Table 1

[0105] In Example 1, both the first ionization structure YS and the second ionization structure YS' undergo two cycles, each cycle includes three ion layers and the ionization rates decrease in the order of 80%, 60%, and 40%.

[0106] In the second embodiment, both the first ionization structure YS and the second ionization structure YS' include only one ion layer with an ionization rate of 80%;

[0107] In Example 3, both the first ionization structure YS and the second ionization structure YS' undergo two cycles, each cycle includes three ion layers and the ionization rates increase in increments of 40%, 60%, and 80%.

[0108] In Example 4, both the first ionization structure YS and the second ionization structure YS′ undergo two cycles, each cycle including three ion layers, wherein the ionization rates of the three ion layers of the first ionization structure YS increase in increments of 40%, 60%, and 80%, and the ionization rates of the three ion layers of the second ionization structure YS′ decrease in increments of 80%, 60%, and 40%.

[0109] In Example 5, both the first ionization structure YS and the second ionization structure YS' undergo two cycles, each cycle including three ion layers, wherein the ionization rates of the three ion layers of the first ionization structure YS vary from 40%, 80%, and 60%, and the ionization rates of the three ion layers of the second ionization structure YS' vary from 80%, 40%, and 60%.

[0110] In Example 6, both the first ionization structure YS and the second ionization structure YS' undergo two cycles, each cycle including three ion layers, wherein the ionization rates of the three ion layers of the first ionization structure YS in the first cycle increase by 40%, 60%, and 80%, and the ionization rates of the three ion layers in the second cycle decrease by 80%, 60%, and 40%, and the ionization rates of the three ion layers of the second ionization structure YS' in the first cycle decrease by 80%, 60%, and 40%, and the ionization rates of the three ion layers in the second cycle increase by 40%, 60%, and 80%.

[0111] In Example 7, the first ionization structure YS performs one cycle, and the second ionization structure YS' performs two cycles. Each cycle includes three ion layers, wherein the ionization rates of the three ion layers of the first ionization structure YS increase in a sequence of 40%, 60%, and 80%, and the ionization rates of the three ion layers of the second ionization structure YS' decrease in a sequence of 80%, 60%, and 40%.

[0112] In Example 8, both the first ionization structure YS and the second ionization structure YS' undergo two cycles, each cycle includes three ion layers and the ionization rates decrease by 80%, 60%, and 40%. The first target material is an aluminum oxide target material, and the third target material is an aluminum target material.

[0113] In the above embodiment, the higher the density of the coating close to the base film (ie, the higher the ionization rate), the better the adhesion and the better the mechanical properties. At the same time, the addition of metal oxides can enhance the corrosion resistance without significantly changing the mechanical properties.

[0114] The composite current collector prepared by the method and apparatus proposed in this application consists of a polymer base film, metal / non-metallic coatings on both sides of the base film, and an outermost metal layer. The intermediate coating group is composed of ion layer depositions with different ionization rates, and multiple similar cyclic coatings can be present within the required thickness range. By adjusting the ionization rate during the evaporation process to prepare the intermediate layer group, the bonding between the base film and subsequent metal layers is enhanced, resulting in improved density and reduced stress within the film layer.

[0115] As used herein, the terms "approximately," "substantially," "substantially," and "about" are used to describe and take into account small variations. When used in conjunction with an event or circumstance, the terms may refer to instances where the event or circumstance occurred exactly as well as instances where the event or circumstance occurred very approximately. As used herein with respect to a given value or range, the term "approximately" generally means within ±10%, ±5%, ±1%, or ±0.5% of the given value or range. Ranges may be expressed herein as from one endpoint to another or between two endpoints. Unless otherwise specified, all ranges disclosed herein include endpoints. The term "substantially coplanar" may refer to two surfaces that are positioned along the same plane within a few micrometers (μm), for example, within 10 μm, within 5 μm, within 1 μm, or within 0.5 μm positioned along the same plane. When referring to a value or characteristic that is "substantially" the same, the term may refer to a value that is within ±10%, ±5%, ±1%, or ±0.5% of the average of the stated values.

[0116] As used herein, the terms "approximately," "substantially," "essentially," and "about" are used to describe and explain small variations. When used in conjunction with an event or circumstance, the terms may refer to instances where the event or circumstance occurred exactly as well as instances where the event or circumstance occurred very approximately. For example, when used in conjunction with a numerical value, the terms may refer to a range of variation of less than or equal to ±10% of the numerical value, e.g., less than or equal to ±5%, less than or equal to ±4%, less than or equal to ±3%, less than or equal to ±2%, less than or equal to ±1%, less than or equal to ±0.5%, less than or equal to ±0.1%, or less than or equal to ±0.05%. For example, two values ​​may be considered "substantially" or "approximately" the same if the difference between them is less than or equal to ±10% of the mean of the values ​​(e.g., less than or equal to ±5%, less than or equal to ±4%, less than or equal to ±3%, less than or equal to ±2%, less than or equal to ±1%, less than or equal to ±0.5%, less than or equal to ±0.1%, or less than or equal to ±0.05%). For example, "substantially" parallel can refer to an angular variation of less than or equal to ±10° relative to 0°, e.g., less than or equal to ±5°, less than or equal to ±4°, less than or equal to ±3°, less than or equal to ±2°, less than or equal to ±1°, less than or equal to ±0.5°, less than or equal to ±0.1°, or less than or equal to ±0.05°. For example, "substantially" perpendicular can refer to an angular variation range of less than or equal to ±10° relative to 90°, for example, less than or equal to ±5°, less than or equal to ±4°, less than or equal to ±3°, less than or equal to ±2°, less than or equal to ±1°, less than or equal to ±0.5°, less than or equal to ±0.1°, or less than or equal to ±0.05°.

[0117] For example, two surfaces may be considered coplanar or substantially coplanar if the displacement between the two surfaces is equal to or less than 5 μm, equal to or less than 2 μm, equal to or less than 1 μm, or equal to or less than 0.5 μm. A surface may be considered planar or substantially planar if the displacement between any two points on the surface relative to the plane is equal to or less than 5 μm, equal to or less than 2 μm, equal to or less than 1 μm, or equal to or less than 0.5 μm.

[0118] As used herein, the singular terms "a," "an," and "the" may include plural referents unless the context clearly dictates otherwise. In the description of some embodiments, a component provided "on" or "over" another component may encompass both the case where the former component is directly on (e.g., physically in contact with) the latter component and the case where one or more intermediate components are located between the former and the latter component.

[0119] As used herein, spatially relative terms such as "below," "beneath," "lower," "above," "upper," "lower," "left," "right," etc., may be used herein for ease of description to describe the relationship of one component or feature to another component or feature as illustrated in the figures. Spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. The device may be oriented in other ways (rotated 90 degrees or in other orientations), and the spatially relative descriptors used herein should be interpreted accordingly. It should be understood that when a component is referred to as being "connected to" or "coupled to" another component, it can be directly connected or coupled to the other component or intervening components may be present.

[0120] The foregoing summarizes several embodiments and detailed features of the present disclosure. The embodiments described in this disclosure can be readily used as a basis for designing or modifying other processes and structures for performing the same or similar purposes and / or obtaining the same or similar advantages of the embodiments introduced herein. These equivalent constructions do not depart from the spirit and scope of the present disclosure and various changes, substitutions, and modifications may be made without departing from the spirit and scope of the present disclosure.

Claims

1. A method for preparing a composite current collector for a lithium battery, characterized in that, Including: Evaporating a first target to generate first target vapor; Ionizing the first target vapor to form a first ionized structure on a first surface of a base film, the first ionized structure including at least two ion layers, the at least two ion layers having different ionization rates respectively; and Evaporating a second target to form a metal layer including the second target above the first ionized structure.

2. The method according to claim 1, wherein Ionizing the first target vapor to form the first ionized structure on the first surface of the base film includes: Forming a first ion layer above the first surface of the base film; Forming a second ion layer above the first ion layer; and Forming a third ion layer above the second ion layer; Wherein the ionization rates of the first, second, and third ion layers are different from each other.

3. The method according to claim 2, wherein The ionization rates of the first, second, and third ion layers increase.

4. The method according to claim 2, wherein The ionization rates of the first, second, and third ion layers decrease.

5. The method according to claim 2, wherein The ionization rates of the first and third ion layers are less than the ionization rate of the second ion layer.

6. The method according to claim 2, wherein The ionization rates of the first and third ion layers are greater than the ionization rate of the second ion layer.

7. The method according to claim 2, wherein Ionizing the first target vapor to form the first ionized structure on the first surface of the base film further includes: Forming a fourth ion layer above the third ion layer; Forming a fifth ion layer above the fourth ion layer; and Forming a sixth ion layer above the fifth ion layer; Wherein the ionization rates of the fourth, fifth, and sixth ion layers are different from each other.

8. The method according to claim 7, characterized in that, The ionization rates of the fourth, fifth, and sixth ion layers increase.

9. The method according to claim 7, wherein The ionization rates of the fourth, fifth, and sixth ion layers decrease.

10. The method according to claim 7, characterized in that, The ionization rates of the fourth and sixth ion layers are less than the ionization rate of the fifth ion layer.

11. The method according to claim 7, wherein The ionization rates of the fourth and sixth ion layers are greater than the ionization rate of the fifth ion layer.

12. The method according to any one of claims 1 to 11, characterized in that, Further including: Evaporating a third target to generate third target vapor; Ionizing the third target vapor to form a second ionized structure on a second surface of the base film, wherein the second surface is opposite to the first surface, the second ionized structure including at least two ion layers, the at least two ion layers having different ionization rates respectively; and Evaporating the second target to form a metal layer including the second target above the second ionized structure.

13. The method according to claim 12, wherein Forming the second ionized structure on the second surface of the base film includes: Forming a seventh ion layer above the second surface of the base film; Forming an eighth ion layer above the seventh ion layer; and Forming a ninth ion layer above the eighth ion layer; Wherein the ionization rates of the seventh, eighth, and ninth ion layers are different from each other.

14. The method according to claim 13, wherein The ionization rates of the seventh, eighth, and ninth ion layers increase.

15. The method according to claim 13, wherein The ionization rates of the seventh, eighth, and ninth ion layers decrease.

16. The method according to claim 13, wherein The ionization rates of the seventh and ninth ion layers are less than the ionization rate of the eighth ion layer.

17. The method according to claim 13, wherein The ionization rates of the seventh and ninth ion layers are greater than the ionization rate of the eighth ion layer.

18. The method according to claim 13, wherein Forming the second ionized structure on the second surface of the base film further includes: Forming a tenth ion layer above the ninth ion layer; Forming an eleventh ion layer above the tenth ion layer; and Forming a twelfth ion layer above the eleventh ion layer; The ionization rates of the tenth, eleventh, and twelfth ion layers are different from each other.

19. The method according to claim 18, wherein The ionization rates of the tenth, eleventh, and twelfth ion layers increase.

20. The method according to claim 18, wherein The ionization rates of the tenth, eleventh, and twelfth ion layers decrease.

21. The method according to claim 18, characterized in that The ionization rates of the tenth and twelfth ion layers are less than the ionization rate of the eleventh ion layer.

22. The method according to claim 18, wherein The ionization rates of the tenth and twelfth ion layers are greater than the ionization rate of the eleventh ion layer.

23. The method according to claim 12, wherein The first, second, and third target materials are the same, partially the same, or different from each other.

24. The method according to claim 12, wherein The first target material includes aluminum oxide, and the third target material includes aluminum.

25. The method according to claim 1, characterized in that The base film includes any one or a mixture of more than one of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyethylene, polypropylene, polyvinyl chloride, polyvinylidene fluoride, polytetrafluoroethylene, polyphenylene sulfide, polyphenylene ether, polyacrylonitrile, cellulose acetate, polystyrene, or polyimide.

26. The method according to claim 1, wherein The first ionization structure includes at least one of aluminum, copper, nickel, tin, zinc, chromium, iron, lithium, cobalt, and their oxides or alloys, or includes at least one of silicon oxide, silicon carbide, silicon nitride, graphite, carbon nanotubes, and carbon fibers.

27. The method according to claim 1, wherein The thickness of the first ionization structure is less than 1000 nm.

28. The method according to claim 1, wherein The metal layer includes at least one of aluminum, copper, lithium, and their oxides or alloys.

29. The method according to claim 1, wherein The thickness of the metal layer is less than 50 μm.

30. An apparatus for preparing a composite current collector for a lithium battery, characterized in that, Configured to perform the method according to claim 1, including: A conveying assembly for conveying the base film; An evaporation assembly disposed below the conveying assembly and configured to evaporate the target material; An ionization device disposed above the evaporation assembly and configured to ionize the vapor of the target material to form at least two ion layers on the base film, and the at least two ion layers respectively have different ionization rates; Wherein the conveying assembly includes a conveying roller configured to carry the base film so that the film to be coated of the base film faces the evaporation assembly and the ionization device, and the conveying roller includes a cooling component configured to control the temperature of the base film during the coating of the base film to prevent the base film from overheating and shrinking and deforming due to the formation of the at least two ion layers with different ionization rates.

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