A modified lithium metal negative electrode current collector and a preparation method thereof

Abstract

The application relates to a modified lithium metal negative electrode current collector and a preparation method, which comprises the following steps: Al powder and YbAl3 powder are simultaneously heated and vapor-deposited onto the surface of a substrate to obtain a substrate with a YbAl3 precursor modified film; and the substrate with the YbAl3 precursor modified film is annealed in an inert environment and cooled to obtain the modified lithium metal negative electrode current collector. The Al powder and the YbAl3 powder are simultaneously heated and vapor-deposited onto the surface of the substrate, and a YbAl3 modified film is formed through annealing; through the high conductivity of YbAl3, the electronic transmission in the battery is accelerated, the uniform deposition of lithium ions is effectively induced, the lithium dendrite growth is avoided, the coulomb efficiency of the lithium ion battery is improved, and the cycle stability of the lithium ion battery is improved; through the high thermal conductivity of YbAl3, the local high-temperature problem in the initial heating stage of the battery is solved, and the thermal runaway problem of the battery is prevented.

Description

Technical Field

[0001] This invention belongs to the field of lithium battery material technology, specifically relating to a modified lithium metal anode current collector and its preparation method. Background Technology

[0002] In recent years, the low energy density of lithium-ion batteries has failed to meet the demands of increasingly advanced energy storage devices, leading to a growing need for higher energy density in rechargeable batteries. Consequently, lithium metal anodes, boasting an ultra-high theoretical specific capacity of 3860 mAh / g and a low redox potential of -3.04 V, have attracted widespread attention.

[0003] However, due to the high reactivity and uncontrollable volume expansion of lithium metal, lithium metal anodes cause many intractable problems during charge-discharge cycles, such as lithium dendrite formation, dead lithium, volume expansion, and low coulombic efficiency. These problems can lead to short circuits, fires, and explosions during battery use. These issues severely hinder the commercialization of lithium metal batteries.

[0004] To address the problems encountered in lithium metal batteries during charge-discharge cycles, particularly the uneven deposition of lithium ions, which leads to lithium dendrite formation and reduced coulombic efficiency, and where localized high temperatures and continuous dendrite growth can puncture the separator, causing fires, explosions, and other safety issues, thus affecting battery lifespan, researchers have explored various methods. These include dual-salt and triple-salt electrolyte systems to stabilize the SEI interface, organic / inorganic hybrid solid electrolytes, and the use of three-dimensional current collectors to guide uniform lithium ion deposition. However, these methods all suffer from significant gaps between research and practical application, as well as inconsistent quality. Therefore, further exploration of other simple and efficient materials and methods to solve the problem of uneven lithium ion deposition in lithium-ion batteries is needed. Summary of the Invention

[0005] The purpose of this invention is to overcome the above-mentioned technical deficiencies and provide a modified lithium metal anode current collector and its preparation method, thereby solving the technical problems of uneven lithium ion deposition and local high temperature in lithium-ion batteries in the prior art, and improving the cycle stability and safety performance of lithium-ion batteries.

[0006] To achieve the above-mentioned technical objectives, the technical solution provided by this invention is as follows:

[0007] In a first aspect, the present invention provides a method for preparing a modified lithium metal anode current collector, comprising the following steps:

[0008] Al powder and YbAl3 powder were simultaneously heated and vapor-deposited onto the substrate surface to obtain a substrate with a YbAl3 precursor modified film.

[0009] The substrate with the YbAl3 precursor modified film was annealed and cooled in an inert environment to obtain the modified lithium metal anode current collector.

[0010] Secondly, the present invention provides a modified lithium metal anode current collector prepared by the above-mentioned preparation method.

[0011] Compared with the prior art, the beneficial effects of the present invention include:

[0012] This invention involves simultaneously heating and vapor-depositing Al powder and YbAl3 powder onto a substrate surface, followed by annealing to form a YbAl3 modified thin film. The invention utilizes the YbAl3 modified thin film to modify the current collector. Leveraging the high electrical conductivity of YbAl3, it accelerates electron transport within the battery, effectively inducing uniform lithium-ion deposition, preventing lithium dendrite growth, improving the coulombic efficiency of the lithium-ion battery, and enhancing its cycle stability. Furthermore, the high thermal conductivity of YbAl3 addresses the issue of localized high temperatures during the initial heating phase of the battery, preventing thermal runaway. Attached Figure Description

[0013] Figure 1 This is a physical image of the modified lithium metal anode current collector (modified copper foil) obtained in Example 1 of the present invention;

[0014] Figure 2 XRD analysis of the modified lithium metal anode current collector obtained in Example 2 of this invention;

[0015] Figure 3 EDS analysis of the modified lithium metal anode current collector obtained in Example 3 of this invention;

[0016] Figure 4 This is a surface microstructure diagram of the modified lithium metal anode current collector (modified copper foil) obtained in Example 4 of the present invention;

[0017] Figure 5 The microstructure of lithium deposition in the modified lithium metal anode current collector obtained in Example 4 of this invention under organic ether electrolyte DOL / DME is shown.

[0018] Figure 6 This is a comparison graph showing the cycle coulombic efficiency of the lithium-ion battery constructed in Example 5 of the present invention and the lithium-ion battery constructed in Comparative Example 1 in the organic ether electrolyte DOL / DME.

[0019] Figure 7 The microstructure of lithium deposition obtained by conventional copper foil deposition is shown in Comparative Example 1.

[0020] Figure 8 The microstructure of lithium deposition in the modified lithium metal anode current collector obtained in Comparative Example 2 under organic ether electrolyte DOL / DME is shown.

[0021] Figure 9 The diagram shows the cycle coulombic efficiency of the lithium-ion battery constructed in Comparative Example 2 in the organic ether electrolyte DOL / DME. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0023] A modified lithium metal anode current collector includes a substrate and a YbAl3 modified film disposed on the surface of the substrate; the YbAl3 modified film is obtained by simultaneously heating and vapor-depositing Al powder and YbAl3 powder and then annealing.

[0024] Preferably, the YbAl3 modified thin film material is obtained by vacuum evaporation onto the surface of the current collector substrate and then annealing in an inert environment.

[0025] Preferably, the substrate includes a current collector, a separator, or an electrode material. When the substrate is a current collector, the YbAl3 modified film mainly functions to induce uniform lithium deposition and suppress lithium dendrite formation, while also promoting uniform heat dissipation of the battery. When the substrate uses a separator or electrode material instead of a current collector, a modified separator or modified electrode is obtained, and the YbAl3 modified film mainly functions to dissipate heat uniformly and prevent thermal runaway of the battery.

[0026] More preferably, the current collector substrate can be a copper substrate or a carbon substrate, etc. Even further, the copper substrate can be copper foil, copper mesh, or copper foam, etc.; the carbon substrate can be carbon fiber cloth, carbon nanotubes, or graphite, etc.

[0027] More preferably, the diaphragm can be a polypropylene diaphragm or a solid electrolyte, etc.

[0028] More preferably, the electrode material can be sulfur, lithium iron phosphate, or ternary cathode material, etc.

[0029] A method for preparing a modified lithium metal anode current collector includes the following steps:

[0030] 1) A YbAl3 precursor film is deposited on the surface of a current collector substrate or a solid electrolyte substrate using a vacuum evaporation process; in the vacuum evaporation step, the YbAl3 precursor film is deposited onto the substrate surface by simultaneously heating Al powder and YbAl3 powder.

[0031] 2) Anneal and cool the product obtained in step 1) in an inert environment to obtain the modified lithium metal anode current collector.

[0032] In the above scheme, the raw materials used in the vacuum evaporation process are Al powder (99.999%) and YbAl3 powder synthesized by self-propagating high temperature.

[0033] Preferably, when using a vacuum evaporation process, the Al powder is heated for 5-10 minutes at a speed of [missing information]. (Further optimization) The current used is 150–180A (more preferably 150–160A), and the pressure under vacuum conditions is 5 × 10⁻⁶. -4 ~6×10 -4 Pa.

[0034] The heating time for the YbAl3 powder is 5–10 min, and the heating rate is [missing information]. (Further optimization) The current used is 180–210 A (more preferably 200–210 A); the pressure under vacuum conditions is 5 × 10⁻⁶. -4 ~6×10 -4 Pa.

[0035] Preferably, the annealing step is performed in a tube furnace.

[0036] Preferably, the annealing step is performed at a temperature of 600–650°C for 5–10 minutes.

[0037] Preferably, the annealing step is performed under a protective atmosphere such as argon.

[0038] Preferably, the mass ratio of Al powder to YbAl3 powder is 1:(4-6), more preferably 1:(4.5-5.5).

[0039] Application of a YbAl3 modified thin film in inducing uniform lithium-ion deposition.

[0040] Application of a YbAl3 modified film in suppressing lithium dendrite growth.

[0041] Lithium-ion deposition mainly includes the deposition of lithium onto the current collector surface during negative electrode preparation, and the deposition of lithium onto the negative electrode surface during charge-discharge cycles. Both of these aspects can lead to uneven lithium deposition.

[0042] This invention involves preparing a YbAl3 modified thin film on the surface of a current collector, and then applying the film at a current density of 0.5–2 mA cm⁻¹. -2 (preferably 1mA cm) -2Under these conditions, a lithium layer is further deposited on the surface of the modified lithium metal anode current collector to prepare a lithium metal anode. As the anode in a full battery (such as lithium iron phosphate or ternary system), it can achieve uniform deposition of lithium ions on the current collector surface, which is beneficial to significantly improve the coulombic efficiency and cycle stability of the resulting lithium-ion battery. Furthermore, due to the extremely high electrical and thermal conductivity of YbAl3, it can promote the uniform diffusion of heat inside the battery, which is beneficial to the thermal safety of the battery and has a preventive effect on battery thermal runaway.

[0043] The present invention has the following main technical advantages:

[0044] 1. This invention uses YbAl3 material to modify current collectors, electrode materials, or separators. By utilizing the high electrical conductivity of YbAl3, it accelerates electron transport within the battery, effectively inducing uniform lithium-ion deposition, avoiding lithium dendrite growth, improving the coulombic efficiency of lithium-ion batteries, and enhancing the cycle stability of lithium-ion batteries. Furthermore, the high thermal conductivity of YbAl3 solves the problem of localized high temperatures during the initial heating stage of the battery, preventing thermal runaway.

[0045] 2. This invention uses thin film deposition combined with annealing modification to prepare YbAl3 thin film modified lithium metal anode current collectors or separators. The process involved is simple, and the target product can be obtained within one hour, making it suitable for large-scale production.

[0046] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0047] In the following examples, the YbAl3 powder used was prepared by self-propagating high-temperature synthesis.

[0048] Example 1

[0049] A modified lithium metal anode current collector includes a base copper foil and a modified layer disposed on its surface. The modified layer is obtained by vacuum evaporation of Al powder and YbAl3 powder onto the surface of the copper foil base, followed by annealing. The specific preparation steps are as follows:

[0050] 1) Weigh out 0.95g of YbAl3 powder and 0.2g of Al powder;

[0051] 2) Fix the copper foil onto the base of the vacuum chamber of the vacuum evaporation coating equipment. Place the raw material powder onto the evaporation boat and fix the evaporation boat between the two electrodes of the vacuum chamber. Evacuate the vacuum chamber to a pressure of 6 × 10⁻⁶. -4 Pa, then simultaneously deposit YbAl3 powder and Al powder, wherein the current used for YbAl3 deposition is 200A, and the speed is... The current used for evaporating Al powder was 150A, and the speed was... Meanwhile, the vapor deposition time is 5 minutes;

[0052] 3) Then transfer it to a tube furnace and anneal it under an argon atmosphere at a temperature of 630°C for 5 min (both heating and cooling rates are set to 5°C / min) to obtain the modified lithium metal anode current collector.

[0053] The physical image of the modified lithium metal anode current collector obtained in this embodiment is shown below. Figure 1 As shown, the resulting thin film layer is grayish-black.

[0054] Example 2

[0055] A modified lithium metal anode current collector includes a base copper foil and a modified layer disposed on its surface. The modified layer is obtained by vacuum evaporation of Al powder and YbAl3 powder onto the surface of the copper foil base, followed by annealing. The specific preparation steps are as follows:

[0056] 1) Weigh out 0.93g of YbAl3 powder and 0.18g of Al powder;

[0057] 2) Fix the copper foil onto the base of the vacuum chamber of the vacuum evaporation coating equipment. Place the raw material powder onto the evaporation boat and fix the evaporation boat between the two electrodes in the vacuum chamber. Evacuate the vacuum chamber to a pressure of 5.8 × 10⁻⁶. -4 Pa, then simultaneously vapor-deposit YbAl3 powder and Al powder, wherein the vapor-deposit current used for YbAl3 is 210A, and the speed is... The current used for evaporating Al powder was 155A, and the speed was... Meanwhile, the vapor deposition time is 5 minutes;

[0058] 3) Then transfer it to a tube furnace and anneal it under an argon atmosphere at a temperature of 630°C for 10 min (both heating and cooling rates are set to 5°C / min) to obtain the modified lithium metal anode current collector.

[0059] The modified lithium metal anode current collector obtained in this embodiment was subjected to XRD phase analysis, such as... Figure 2 As shown, the obtained product has single-phase YbAl3 diffraction peaks and good crystallinity.

[0060] Example 3

[0061] A modified lithium metal anode current collector includes a base copper foil and a modified layer disposed on its surface. The modified layer is obtained by vacuum evaporation of Al powder and YbAl3 powder onto the surface of the copper foil base, followed by annealing. The specific preparation steps are as follows:

[0062] 1) Weigh out 0.98g of YbAl3 powder and 0.21g of Al powder;

[0063] 2) Fix the copper foil onto the base of the vacuum chamber of the vacuum evaporation coating equipment. Place the raw material powder onto the evaporation boat and fix the evaporation boat between the two electrodes of the vacuum chamber. Evacuate the vacuum chamber to a pressure of 6 × 10⁻⁶. -4 Pa, then simultaneously deposit YbAl3 powder and Al powder, wherein the current used for YbAl3 deposition is 200A, and the speed is... The current used for evaporating Al powder was 160A, and the speed was... Meanwhile, the vapor deposition time is 5 minutes;

[0064] 3) Then transfer it to a tube furnace and anneal it under an argon atmosphere at a temperature of 640°C for 5 min (both heating and cooling rates are set to 5°C / min) to obtain the modified lithium metal anode current collector.

[0065] The modified lithium foil anode current collector obtained in this embodiment was subjected to EDS composition analysis, and the results are shown below. Figure 3 The atomic percentage of Yb is 24.81%, and the atomic percentage of Al is 75.19%. Calculations show that the molecular formula of the product is YbAl. 3.03 It is consistent with the nominal composition.

[0066] Example 4

[0067] A modified lithium metal anode current collector includes a base copper foil and a modified layer disposed on its surface. The modified layer is obtained by vacuum evaporation of Al powder and YbAl3 powder onto the surface of the copper foil base, followed by annealing. The specific preparation steps are as follows:

[0068] 1) Weigh out 0.95g of YbAl3 powder and 0.21g of Al powder;

[0069] 2) Fix the copper foil onto the base of the vacuum chamber of the vacuum evaporation coating equipment. Place the raw material powder onto the evaporation boat and fix the evaporation boat between the two electrodes in the vacuum chamber. Evacuate the vacuum chamber to a pressure of 5 × 10⁻⁶. -4 Pa, then simultaneously deposit YbAl3 powder and Al powder, wherein the current used for YbAl3 deposition is 200A, and the speed is... The current used for evaporating Al powder was 155A, and the speed was... Meanwhile, the vapor deposition time is 5 minutes;

[0070] 3) Then transfer it to a tube furnace and anneal it under an argon atmosphere at a temperature of 630°C for 8 minutes (both heating and cooling rates are set to 5°C / min) to obtain the modified lithium metal anode current collector.

[0071] Field emission scanning electron microscopy revealed that the YbAl3 grain size is approximately 100 nm. Figure 4 As shown.

[0072] The modified lithium-ion battery negative electrode current collector obtained in this embodiment was used to assemble a half-cell with a 12mm lithium sheet. The electrolyte was an organic ether electrolyte, DOL / DME, and the separator was a polypropylene separator used in commercial lithium batteries. The microstructure of lithium deposition was investigated. The battery was allowed to stand for 12 hours before testing, under the condition that the current density was 1mA / cm². 2 Deposition capacity 4mAh / cm 2 The lithium deposits were observed to be gradually smooth and rounded using field emission scanning electron microscopy (FET), as shown in the following figure. Figure 5 .

[0073] Example 5

[0074] A modified lithium metal anode current collector includes a base copper foil and a modified layer disposed on its surface. The modified layer is obtained by vacuum evaporation of Al powder and YbAl3 powder onto the surface of the copper foil base, followed by annealing. The specific preparation steps are as follows:

[0075] 1) Weigh out 0.94g of YbAl3 powder and 0.19g of Al powder;

[0076] 2) Fix the copper foil onto the base of the vacuum chamber of the vacuum evaporation coating equipment. Place the raw material powder onto the evaporation boat and fix the evaporation boat between the two electrodes of the vacuum chamber. Evacuate the vacuum chamber to a pressure of 5.5 × 10⁻⁶. -4 Pa, then simultaneously vapor-deposit YbAl3 powder and Al powder, wherein the vapor-deposit current used for YbAl3 is 210A, and the speed is... The current used for evaporating Al powder was 150A, and the speed was... Meanwhile, the vapor deposition time is 5 minutes;

[0077] 3) Then transfer it to a tube furnace and anneal it under an argon atmosphere at a temperature of 630°C for 5 min (both heating and cooling rates are set to 5°C / min) to obtain the modified lithium metal anode current collector.

[0078] The modified lithium metal anode current collector obtained in this embodiment was used as the positive electrode, and a 12mm lithium sheet was used as the negative electrode to assemble a half-cell. The electrolyte was an organic ether electrolyte DOL / DME, and the separator was a polypropylene separator used in commercial lithium batteries. The coulombic efficiency of the obtained battery was investigated. The battery was tested after standing for 12 hours under the following conditions: current density 1mA / cm². 2 The capacity is 1mAh / cm 2 The test results are as follows Figure 6 As shown.

[0079] The modified lithium metal anode current collectors obtained in the above embodiments have similar performance.

[0080] The following comparison uses the battery containing the YbAl3 modified layer in the above embodiments with a specific comparative example to illustrate in detail the beneficial effects of the negative electrode modification material provided by the present invention.

[0081] Comparative Example 1

[0082] The copper foil used in commercial lithium batteries is stamped to obtain a copper foil with a diameter of 12mm, and then assembled into a battery with a 12mm lithium sheet. The electrolyte is an organic ether electrolyte DOL / DME, and the separator is a polypropylene separator used in commercial lithium batteries.

[0083] Figure 6 The graph shows a comparison of the coulombic efficiencies of the lithium-ion batteries obtained in Example 5 and Comparative Example 1. It can be seen that in the DOL / DME ether electrolyte system, the modified lithium metal anode current collector prepared by using YbAl3 modified copper foil in Example 5 can effectively avoid lithium dendrite growth, improve the cycle stability of the lithium-ion battery, and has a significantly higher coulombic efficiency than the lithium-ion battery obtained by using traditional copper foil. The present invention can still maintain a coulombic efficiency of about 90% after 300 cycles, while the coulombic efficiency of the unmodified current collector drops sharply to about 80% after 70 cycles.

[0084] Figure 7 The battery described in Comparative Example 1 was tested under conditions of 1 mA / cm. 2 At current density, deposition capacity is 4 mAh / cm³. 2 The morphology of the lithium metal anode obtained after lithium removal shows that when unmodified copper foil is used as the current collector, lithium will grow in a dendritic form.

[0085] Comparative Example 2

[0086] A modified lithium metal anode current collector includes a base copper foil and a modified layer disposed on its surface. The modified layer is obtained by vacuum evaporation, first pre-plating Al powder onto the surface of the current collector, then depositing Al powder and YbAl3 powder onto the surface of the current collector, followed by annealing. In other words, the copper foil includes an Al powder pre-plating layer and a YbAl3 modified thin film layer. The specific preparation steps are as follows:

[0087] 1) Weigh out one part of YbAl3 powder (0.95g), one part of Al powder (0.21g), and one part of Al powder (0.13g);

[0088] 2) Fix the copper foil onto the base of the vacuum chamber of the vacuum evaporation coating equipment. Place the raw material powder onto the evaporation boat and fix the evaporation boat between the two electrodes in the vacuum chamber. Evacuate the vacuum chamber to a pressure of 5 × 10⁻⁶. -4Pa, first vapor deposit one portion of 0.13g Al powder, controlling the vapor deposition current at 150A, and the speed... The time was 2 minutes. Then, 0.95g of YbAl3 powder and 0.21g of Al powder were simultaneously vapor-deposited. The YbAl3 deposition used a current of 200A and a speed of [missing information]. The current used for evaporating Al powder was 155A, and the speed was... Meanwhile, the vapor deposition time is 5 minutes;

[0089] 3) Then transfer it to a tube furnace and anneal it under an argon atmosphere at a temperature of 630°C for 8 minutes (both heating and cooling rates are set to 5°C / min) to obtain the modified lithium metal anode current collector.

[0090] The lithium-ion battery negative electrode obtained in this comparative example was assembled into a battery using a 12mm lithium sheet. The electrolyte was an organic ether electrolyte, DOL / DME, and the separator was a polypropylene separator used in commercial lithium batteries. The battery was then tested after standing for 12 hours under the following conditions: current density 1 mA / cm². 2 Deposition capacity 4mAh / cm 2 Lithium; field emission scanning electron microscopy revealed that the deposited lithium grew in a dendritic pattern, as shown in the following figure. Figure 8 .

[0091] The lithium-ion battery negative electrode obtained in this embodiment was assembled into a battery with a 12mm lithium sheet. The electrolyte was an organic ether electrolyte, DOL / DME, and the separator was a polypropylene separator used in commercial lithium batteries. The battery was tested after standing for 12 hours under the following conditions: current density 1mA / cm². 2 The capacity is 1mAh / cm 2 The cycle performance dropped significantly, as shown in the test results. Figure 9 As shown, this indicates that adding an Al powder pre-coating layer does not effectively suppress lithium dendrites.

[0092] The specific embodiments of the present invention described above do not constitute a limitation on the scope of protection of the present invention. Any other corresponding changes and modifications made in accordance with the technical concept of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for preparing a modified lithium metal anode current collector, characterized in that, It consists of the following steps: Al powder and YbAl3 powder were simultaneously heated and vapor-deposited onto the substrate surface to obtain a substrate with a YbAl3 precursor modified film. The substrate with the YbAl3 precursor modified film was annealed and cooled in an inert environment to obtain the modified lithium metal anode current collector. The modified lithium metal anode current collector can effectively induce uniform deposition of lithium ions, avoid lithium dendrite growth, improve the coulombic efficiency of lithium-ion batteries, and improve the cycle stability of lithium-ion batteries.

2. The method for preparing the modified lithium metal anode current collector according to claim 1, characterized in that, Vacuum evaporation was used for the deposition, and the heating time was 5-10 minutes.

3. The method for preparing the modified lithium metal anode current collector according to claim 2, characterized in that, During vacuum evaporation, the pressure under vacuum conditions is 5 × 10⁻⁶. -4 ~6×10 -4 Pa.

4. The method for preparing the modified lithium metal anode current collector according to claim 2, characterized in that, During vacuum evaporation, the evaporation rate of Al powder is 10~40 Å / s, and the current used is 150~180 A; the evaporation rate of YbAl3 powder is 10~35 Å / s, and the current used is 180~210 A.

5. The method for preparing the modified lithium metal anode current collector according to claim 1, characterized in that, Annealing is carried out in a tube furnace.

6. The method for preparing the modified lithium metal anode current collector according to claim 1, characterized in that, The annealing process is carried out at a temperature of 600~650℃ for 5~10 minutes.

7. The method for preparing the modified lithium metal anode current collector according to claim 1, characterized in that, The substrate is a copper substrate or a carbon substrate.

8. The method for preparing the modified lithium metal anode current collector according to claim 7, characterized in that, The copper substrate includes copper foil, copper mesh, or copper foam; the carbon substrate includes carbon fiber cloth, carbon nanotubes, or graphite.

9. The method for preparing the modified lithium metal anode current collector according to claim 1, characterized in that, The mass ratio of Al powder to YbAl3 powder is 1:(4-6).

10. The modified lithium metal anode current collector prepared by the preparation method according to any one of claims 1-9.

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