A method for preparing a three-dimensional current collector for a lithium metal battery

Abstract

The application relates to a preparation method of a three-dimensional current collector for a lithium metal battery, and relates to a preparation method of a current collector for a lithium metal battery. The application is used for solving the problems of lithium dendrite growth and large volume change of an existing lithium metal negative electrode during a cycle process. The application introduces abundant micro reaction interfaces by etching the current collector through an oxidizing agent combined with an acid immersion method, promotes local current density reduction and uniform lithium deposition. The application introduces a lithiumophilic modification layer on the surface of the metal-based current collector through coordination precipitation of a chelating agent, effectively inhibits dendrite growth, and promotes reduction of nucleation overpotential in the early stage of lithium deposition and improvement of battery performance. The three-dimensional current collector modified by the lithiumophilic modification is used as a lithium deposition substrate, greatly buffers local larger volume fluctuation during lithium deposition / peeling, and helps to reduce irreversible lithium loss. The application has low reagent cost and can be recycled, is easy to operate, and is suitable for scale production.

Description

Technical Field

[0001] This invention relates to a method for preparing a three-dimensional current collector for lithium metal batteries. Background Technology

[0002] With the rapid development of electric vehicles, energy storage, and high-performance portable electronic devices, lithium metal batteries, using lithium metal as the anode material, are considered one of the key technologies to break through the current energy density bottleneck of batteries. As a representative of next-generation high-energy-density energy storage technology, lithium metal anodes have attracted much attention from academia and industry due to their lightweight, high theoretical specific capacity, and low electrode potential. Furthermore, lithium metal anodes can be combined with high-voltage cathodes (such as lithium-rich layered oxides) and various cathode materials such as sulfur and oxygen, exhibiting superior compatibility and providing important technical support for the exploration of novel electrochemical systems.

[0003] Despite the numerous advantages of lithium metal batteries, several challenges remain during charge and discharge: 1. Dendrite formation: This not only affects coulombic efficiency but also increases the risk of internal short circuits and even thermal runaway. 2. Volume effect: Significant volume changes during lithium deposition / stripping during cycling can easily lead to interface instability and negative electrode pulverization, thus reducing battery cycle life. 3. High reactivity of lithium: Lithium readily undergoes side reactions with the electrolyte, resulting in irreversible consumption of active lithium. To address these challenges, optimizing battery design is essential for improving the cycle performance of lithium metal batteries. This includes modifying three-dimensional current collectors, introducing solid electrolytes, and modifying artificial interface layers. Among these, the structural design of three-dimensional current collectors offers several positive effects, such as reducing local current density, optimizing the composition of the solid electrolyte membrane, and improving lithium deposition morphology.

[0004] Three-dimensional current collector design often significantly improves battery performance by constructing a structured conductive network framework with high specific surface area. Common three-dimensional current collector materials include carbon-based materials (such as carbon nanotubes, graphene, and carbon fibers) and metal-based materials (such as nickel, copper, and aluminum foams or metal coatings). Among them, metal-based three-dimensional current collectors have more extensive application experience in traditional lithium-ion battery systems, and also possess multiple advantages such as high conductivity, high thermal conductivity, and high mechanical strength, making them more suitable for high-rate charge-discharge scenarios. For metal-based three-dimensional current collectors, the following challenges are also faced in the design process: 1. Commonly used Cu and Ni current collectors have limited affinity for lithium, which easily leads to uneven lithium deposition; 2. Highly controllable three-dimensional structures usually require complex manufacturing processes (such as template methods and CVD), resulting in cost and consistency challenges for large-scale commercial applications; 3. The structural design is relatively singular, lacking comprehensive optimization strategies for multi-faceted improvement. Summary of the Invention

[0005] This invention addresses the problems of lithium dendrite growth and large volume changes in existing lithium metal anodes during cycling, and proposes a method for preparing a three-dimensional current collector for lithium metal batteries, thereby further improving the cycle and rate performance of lithium metal batteries.

[0006] The method for preparing the three-dimensional current collector for lithium metal batteries according to the present invention is carried out according to the following steps:

[0007] 1. Place the metal-based current collector in a cleaning agent for ultrasonic cleaning to remove surface contaminants, then air dry;

[0008] The metal-based current collector is copper foil, copper mesh, or Cu foam;

[0009] 2. Dissolve the oxidizing reagent in deionized water to obtain an oxidizing solution; add the oxidizing solution dropwise to a dilute hydrochloric acid solution under continuous stirring to obtain a mixed solution; immerse the metal-based current collector obtained in step 1 into the mixed solution, react for a period of time, remove it, wash it, and dry it.

[0010] The oxidizing agent is ammonium persulfate, hydrogen peroxide, potassium permanganate, or ferric chloride hexahydrate;

[0011] The concentration of the oxidizing solution is 0.005-0.015 mol / L;

[0012] The volume ratio of the oxidizing solution to the dilute hydrochloric acid solution is 1:1;

[0013] 3. Dissolve Zn salt in deionized water to obtain Zn salt solution;

[0014] The concentration of the Zn salt solution is 0.001-0.005 mol / L;

[0015] IV. Dissolve the chelating agent in deionized water to obtain a chelating agent solution;

[0016] The chelating agent is sodium diethyldithiocarbamate trihydrate ((C2H5)2NCSSNa·3H2O), ammonium diethyldithiophosphate ((C2H5O)2P(S)SNH4), or trisodium trithiocyanate (C3N3Na3S3).

[0017] The concentration of the chelating agent solution is 0.002-0.005 mol / L;

[0018] 5. Immerse the metal-based current collector obtained in step 2 into Zn salt solution and chelating agent solution, or into a mixture of Zn salt solution and chelating agent solution, react for a period of time, and then remove it for cleaning and drying.

[0019] The reaction time for the metal-based current collector to be immersed in Zn salt solution or chelating agent solution is 3-10 min; the reaction time for the metal-based current collector to be immersed in a mixture of Zn salt solution and chelating agent solution is 3-10 min.

[0020] The present invention has the following beneficial effects:

[0021] 1. This invention achieves the dual effect of simultaneously removing the oxide layer on the current collector surface and changing the surface roughness by adjusting the type and concentration of the oxidant and the immersion time of the metal-based current collector. The richer reaction interface after etching helps to further reduce the local current density and promotes uniform lithium deposition.

[0022] 2. This invention introduces a lithiophilic modification layer on the surface of a metal-based current collector through the coordination precipitation of a chelating agent, effectively suppressing dendrite growth. When the three-dimensional current collector prepared according to this invention is used in a lithium metal anode, it achieves a current-voltage ratio of 3 mA / cm². 2 Constant current charge-discharge tests were conducted at a current density, and the coulombic efficiency remained as high as 97.6% after 100 cycles, showing a significant improvement in rate performance compared to the unmodified metal-based current collector.

[0023] 3. The present invention utilizes a chelating agent to introduce a lithiophilic modification layer on the surface of a metal-based current collector, which promotes the reduction of the overpotential for lithium nucleation in the early stage of deposition, and the corresponding cycle stability is also significantly improved.

[0024] 4. In view of the "ownerless" problem of lithium during the charging and discharging process, the present invention uses a three-dimensional current collector modified with lithiophilic properties as a lithium deposition substrate. The increased micro-reaction interface and the uniformly dispersed lithiophilic modification greatly buffer the large local volume fluctuations during lithium deposition / stripping, which helps to reduce irreversible lithium loss.

[0025] 5. In the design and preparation of the metal-based three-dimensional current collector, the zinc salt used in this invention is a low-cost metal salt; the chelating agents used—sodium diethyldithiocarbamate trihydrate, ammonium diethyldithiophosphate, and trisodium trithiocyanate—are commonly used in wastewater treatment, are cost-effective, and recyclable. The specific preparation process does not require high-temperature assistance, involving only simple and rapid solution preparation and sample material wetting treatment, making it highly operable and suitable for large-scale production. Attached Figure Description

[0026] Figure 1 The electrochemical impedance spectroscopy of the corresponding fresh battery of the three-dimensional current collector prepared in Example 1;

[0027] Figure 2 The three-dimensional current collector prepared in Example 1 has a current-voltage ratio of 3 mA / cm. 2 Half-cell cycle performance at current density;

[0028] Figure 3 The electrochemical impedance spectroscopy of the corresponding fresh battery of the three-dimensional current collector prepared in Example 2;

[0029] Figure 4 The three-dimensional current collector prepared in Example 2 has a current-voltage ratio of 3 mA / cm. 2 Cyclic performance at current density;

[0030] Figure 5 The image shown is a scanning electron microscope (SEM) image of the three-dimensional current collector prepared in Example 3. Detailed Implementation

[0031] The technical solution of the present invention is not limited to the specific embodiments listed below, but also includes any reasonable combination of the specific embodiments.

[0032] Specific Implementation Method 1: The preparation method of the three-dimensional current collector for lithium metal batteries in this implementation method is carried out according to the following steps:

[0033] 1. Place the metal-based current collector in a cleaning agent for ultrasonic cleaning to remove surface contaminants, then air dry;

[0034] The metal-based current collector is copper foil, copper mesh, or Cu foam;

[0035] 2. Dissolve the oxidizing reagent in deionized water to obtain an oxidizing solution; add the oxidizing solution dropwise to a dilute hydrochloric acid solution under continuous stirring to obtain a mixed solution; immerse the metal-based current collector obtained in step 1 into the mixed solution, react for a period of time, remove it, wash it, and dry it.

[0036] The oxidizing agent is ammonium persulfate, hydrogen peroxide, potassium permanganate, or ferric chloride hexahydrate;

[0037] The concentration of the oxidizing solution is 0.005-0.015 mol / L;

[0038] The volume ratio of the oxidizing solution to the dilute hydrochloric acid solution is 1:1;

[0039] 3. Dissolve Zn salt in deionized water to obtain Zn salt solution;

[0040] The concentration of the Zn salt solution is 0.001-0.005 mol / L;

[0041] IV. Dissolve the chelating agent in deionized water to obtain a chelating agent solution;

[0042] The chelating agent is sodium diethyldithiocarbamate trihydrate ((C2H5)2NCSSNa·3H2O), ammonium diethyldithiophosphate ((C2H5O)2P(S)SNH4), or trisodium trithiocyanate (C3N3Na3S3).

[0043] The concentration of the chelating agent solution is 0.002-0.005 mol / L;

[0044] 5. Immerse the metal-based current collector obtained in step 2 into Zn salt solution and chelating agent solution, or into a mixture of Zn salt solution and chelating agent solution, react for a period of time, and then remove it for cleaning and drying.

[0045] The reaction time for the metal-based current collector to be immersed in Zn salt solution or chelating agent solution is 3-10 min; the reaction time for the metal-based current collector to be immersed in a mixture of Zn salt solution and chelating agent solution is 3-10 min.

[0046] This embodiment has the following beneficial effects:

[0047] 1. This embodiment achieves the dual effect of simultaneously removing the oxide layer on the current collector surface and changing the surface roughness by adjusting the type and concentration of the oxidant and the immersion time of the metal-based current collector. The richer reactive micro-interface after etching helps to further reduce the local current density and promotes uniform lithium deposition.

[0048] 2. This invention introduces a lithiophilic modification layer on the surface of a metal-based current collector through the coordination precipitation of a chelating agent, effectively suppressing dendrite growth. When the three-dimensional current collector prepared according to this invention is used in a lithium metal anode, it achieves a current-voltage ratio of 3 mA / cm². 2 Constant current charge-discharge tests were conducted at a current density, and the coulombic efficiency remained as high as 97.6% after 100 cycles, showing a significant improvement in rate performance compared to the unmodified metal-based current collector.

[0049] 3. The present invention utilizes a chelating agent to introduce a lithiophilic modification layer on the surface of a metal-based current collector, which promotes the reduction of the overpotential for lithium nucleation in the early stage of deposition, and the corresponding cycle stability is also significantly improved.

[0050] 4. In view of the "ownerless" problem of lithium during the charging and discharging process, the present invention uses a three-dimensional current collector modified with lithiophilic properties as a lithium deposition substrate. The increased micro-reaction interface and the uniformly dispersed lithiophilic modification greatly buffer the large local volume fluctuations during lithium deposition / stripping, which helps to reduce irreversible lithium loss.

[0051] 5. In the design and preparation of the metal-based three-dimensional current collector in this embodiment, the zinc salt used is a low-cost metal salt; the chelating agents used, sodium diethyldithiocarbamate trihydrate, ammonium diethyldithiophosphate, and trisodium trithiocyanate, are commonly used in wastewater treatment, are cost-effective, and recyclable. The specific preparation process does not require high-temperature assistance, only involves simple and quick solution preparation and sample material wetting treatment, making it highly operable and suitable for large-scale production.

[0052] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that the ultrasonic cleaning time in step one is 5-20 minutes.

[0053] Specific Implementation Method 3: This implementation method differs from Specific Implementation Method 1 or 2 in that the cleaning agent mentioned in step 1 is one or more of deionized water, anhydrous ethanol, acetone, and dilute hydrochloric acid.

[0054] Specific Implementation Method Four: This implementation method differs from Specific Implementation Method Three in that the concentration of the dilute hydrochloric acid is 0.05-2 mol / L.

[0055] Specific Implementation Method 5: This implementation method differs from one of the specific implementation methods 1 to 4 in that the temperature of the mixed solution in step 2 is 0-25℃.

[0056] Specific Implementation Method Six: This implementation method differs from Specific Implementation Methods One to Five in that the concentration of the dilute hydrochloric acid solution in step two is 0.5-1.5 mol / L.

[0057] Specific Implementation Method Seven: This implementation method differs from Specific Implementation Methods One to Six in that the reaction time of the metal-based current collector in the mixed solution in step two is 0.5-6 hours.

[0058] Specific Implementation Method Eight: This implementation method differs from Specific Implementation Methods One to Seven in that the drying described in step two is blower drying, with a blower drying temperature of 50-100℃ and a time of 15-24 hours.

[0059] Specific Implementation Method Nine: This implementation method differs from Specific Implementation Methods One to Eight in that the Zn salt mentioned in step four is zinc nitrate hexahydrate, zinc acetate, or zinc chloride.

[0060] Specific Implementation Method 10: This implementation method differs from Specific Implementation Methods 1 to 9 in that the drying method described in step 5 is vacuum drying, and the temperature is 50-100℃.

[0061] Example 1:

[0062] The preparation method of the three-dimensional structure current collector for lithium metal batteries in this embodiment is carried out according to the following steps:

[0063] 1. Place the metal-based current collector in a cleaning agent for ultrasonic cleaning to remove surface contaminants, then air dry;

[0064] The metal-based current collector is a copper mesh with dimensions of 3cm × 4cm;

[0065] The ultrasonic cleaning time is 5-20 minutes;

[0066] The cleaning agent is deionized water and anhydrous ethanol;

[0067] 2. Dissolve 0.075g of ammonium persulfate in 40mL of deionized water to obtain an oxidizing solution; under continuous stirring, add the oxidizing solution dropwise to 40mL of 1mol / L dilute hydrochloric acid solution to obtain a mixed solution; immerse the metal-based current collector obtained in step 1 in the mixed solution in an ice bath environment, react for 1 hour, remove it, rinse it with deionized water and anhydrous ethanol in sequence, and then dry it with a forced air at a temperature of 60℃ for 18 hours.

[0068] The obtained three-dimensional current collector material was punched into 14mm electrode sheets, and assembled into corresponding half-cells in the order of negative electrode sheet|PP separator|lithium sheet and tested. The electrolyte used in the half-cells was 1mol / LLiTFSI, DOL:DME=1:1(v:v), 2%LiNO3.

[0069] Figure 1 The electrochemical impedance spectroscopy of the fresh battery corresponding to the three-dimensional current collector prepared in Example 1 is shown; the small impedance arc illustrates the positive effect of removing the surface oxide layer. Figure 2 The three-dimensional current collector prepared in Example 1 has a current-voltage ratio of 3 mA / cm. 2 Half-cell cycle performance at current density, at 3 mA / cm 2 Under the test conditions, the modified copper mesh prepared in Example 1 had an average coulombic efficiency of 96.1% for the corresponding half-cell after 30-80 cycles, which was significantly better than that of the original copper mesh.

[0070] Example 2:

[0071] The preparation method of the three-dimensional structure current collector for lithium metal batteries in this embodiment is carried out according to the following steps:

[0072] 1. Place the metal-based current collector in a cleaning agent for ultrasonic cleaning to remove surface contaminants, then air dry;

[0073] The metal-based current collector is a copper mesh with dimensions of 3cm × 4cm;

[0074] The ultrasonic cleaning time is 5-20 minutes;

[0075] The cleaning agent is deionized water and anhydrous ethanol;

[0076] 2. Dissolve 0.075g of ammonium persulfate in 40mL of deionized water to obtain an oxidizing solution; under continuous stirring, add the oxidizing solution dropwise to 40mL of 1mol / L dilute hydrochloric acid solution to obtain a mixed solution; immerse the metal-based current collector obtained in step 1 in the mixed solution in an ice bath environment, react for 1 hour, remove it, rinse it with deionized water and anhydrous ethanol in sequence, and then dry it with a forced air at a temperature of 60℃ for 18 hours.

[0077] 3. Dissolve 0.037g of zinc nitrate hexahydrate in 80mL of deionized water to obtain a Zn salt solution;

[0078] IV. Dissolve 0.051g of diethyldithiophosphate ammonium in 80mL of deionized water to obtain a chelating agent solution;

[0079] 5. The metal-based current collector obtained in step 2 is sequentially immersed in Zn salt solution and chelating agent solution. After reacting for a period of time, it is taken out and finally cleaned and dried with deionized water and anhydrous ethanol to obtain a three-dimensional current collector material.

[0080] The metal-based current collector is immersed in the Zn salt solution or the chelating agent solution for 5 minutes; the drying method is vacuum drying at a temperature of 60°C.

[0081] The modified three-dimensional current collector material was punched into 14mm electrode sheets and assembled into corresponding lithium batteries in the order of negative electrode sheet | PP separator | lithium sheet. The electrolyte used for the half-cell was 1 mol / L LiTFSI, DOL:DME = 1:1 (v:v), 2% LiNO3. The lithium-deposited three-dimensional current collector was used as the negative electrode, and the lithium iron phosphate electrode sheet was used as the positive electrode to assemble a full cell. The electrolyte used for the full cell was 1 mol / L LiPF6, EC:DEC = 1:1 (v:v), 5% FEC.

[0082] Figure 3 The electrochemical impedance spectroscopy of the fresh battery corresponding to the three-dimensional current collector prepared in Example 2 is shown. The smaller charge transfer resistance and improved cycle performance under high current density of the lithium metal battery corresponding to the three-dimensional current collector modified in Example 2 are mutually corroborated. Figure 4 The three-dimensional current collector prepared in Example 2 has a current-voltage ratio of 3 mA / cm. 2 Cyclic performance diagram at current density, Example 2: Three-dimensional current collector corresponding half-cell at 3 mA / cm² 2 It exhibits excellent cycling stability, with no significant decrease in coulomb efficiency at 80 cycles, and a stable coulomb efficiency of 97.6% after 100 cycles.

[0083] In terms of electrochemical performance testing, Example 2 exhibits a lower charge transfer resistance compared to the fresh battery in Example 1, at 3 mA / cm². 2 Under the test conditions, Example 2 showed a coulombic efficiency 5.23% higher than Example 1 after 80 cycles, and a significantly improved cycle life, indicating that the introduction of lithophile modification plays an important role in reducing irreversible lithium consumption and increasing cycle stability.

[0084] Example 3:

[0085] The preparation method of the three-dimensional structure current collector for lithium metal batteries in this embodiment is carried out according to the following steps:

[0086] 1. Place the metal-based current collector in a cleaning agent for ultrasonic cleaning to remove surface contaminants, then air dry;

[0087] The metal-based current collector is a copper mesh with dimensions of 3cm × 4cm;

[0088] The ultrasonic cleaning time is 5-20 minutes;

[0089] The cleaning agent is deionized water and anhydrous ethanol;

[0090] 2. Dissolve 0.075g of ammonium persulfate in 40mL of deionized water to obtain an oxidizing solution; under continuous stirring, add the oxidizing solution dropwise to 40mL of 1mol / L dilute hydrochloric acid solution to obtain a mixed solution; immerse the metal-based current collector obtained in step 1 in the mixed solution in an ice bath environment, react for 1 hour, remove it, rinse it with deionized water and anhydrous ethanol in sequence, and then dry it with a forced air at a temperature of 60℃ for 18 hours.

[0091] 3. Dissolve 0.037g of zinc nitrate hexahydrate in 80mL of deionized water to obtain a Zn salt solution;

[0092] IV. Dissolve 0.056g of sodium diethyldithiocarbamate trihydrate in 80mL of deionized water to obtain a chelating agent solution;

[0093] 5. The metal-based current collector obtained in step 2 is sequentially immersed in Zn salt solution and chelating agent solution. After reacting for a period of time, it is taken out and finally cleaned and dried with deionized water and anhydrous ethanol to obtain a three-dimensional current collector material.

[0094] The metal-based current collector is immersed in the Zn salt solution or the chelating agent solution for 5 minutes; the drying method is vacuum drying at a temperature of 60°C.

[0095] Figure 5 The image shown is a scanning electron microscope (SEM) image of the three-dimensional current collector prepared in Example 3. Figure 5 The results show that when diethyldithiocarbamate is involved in the modification of the three-dimensional current collector, it forms a relatively smooth coating layer on the copper mesh surface, with relatively uniform coverage and localized nano / micron-sized particles. This surface state differs from that after oxidation treatment due to the coordination of diethyldithiocarbamate with zinc ions and their adsorption on the copper mesh surface.

[0096] In this embodiment, the zinc salt used in the three-dimensional current collector structure design is a low-value metal salt. The chelating agent used is a commonly used heavy metal capture agent, which is widely available and has low usage costs. In addition to controllable raw material costs, the preparation process of this embodiment is simple and efficient, requiring only stirring, sequential immersion, and drying. It is also applicable to various metal-based current collector materials such as copper foil and copper mesh, and has prospects for mass production applications.

Claims

1. A method for preparing a three-dimensional current collector for lithium metal batteries, characterized in that: The preparation method of the three-dimensional current collector for lithium metal batteries is carried out according to the following steps:

1. Place the metal-based current collector in a cleaning agent for ultrasonic cleaning to remove surface contaminants, then air dry; The metal-based current collector is copper foil, copper mesh, or Cu foam; 2. Dissolve the oxidizing reagent in deionized water to obtain an oxidizing solution; The oxidizing solution was added dropwise to the dilute hydrochloric acid solution under continuous stirring to obtain a mixed solution; the metal-based current collector obtained in step one was immersed in the mixed solution, and after reacting for a period of time, it was taken out, washed, and dried. The oxidizing agent is ammonium persulfate, hydrogen peroxide, potassium permanganate, or ferric chloride hexahydrate; The concentration of the oxidizing solution is 0.005-0.015 mol / L; The volume ratio of the oxidizing solution to the dilute hydrochloric acid solution is 1:1; 3. Dissolve Zn salt in deionized water to obtain Zn salt solution; The concentration of the Zn salt solution is 0.001-0.005 mol / L; IV. Dissolve the chelating agent in deionized water to obtain a chelating agent solution; The chelating agent is sodium diethyldithiocarbamate trihydrate, sodium diethyldithiophosphate, or trisodium trithiocyanate. The concentration of the chelating agent solution is 0.002-0.005 mol / L; 5. Immerse the metal-based current collector obtained in step 2 into Zn salt solution and chelating agent solution, or into a mixture of Zn salt solution and chelating agent solution, react for a period of time, and then remove it for cleaning and drying. The reaction time for the metal-based current collector to be immersed in Zn salt solution or chelating agent solution is 3-10 min; the reaction time for the metal-based current collector to be immersed in a mixture of Zn salt solution and chelating agent solution is 3-10 min.

2. The method for preparing a three-dimensional current collector for lithium metal batteries according to claim 1, characterized in that: The ultrasonic cleaning time described in step one is 5-20 minutes.

3. The method for preparing a three-dimensional current collector for lithium metal batteries according to claim 1, characterized in that: The cleaning agent mentioned in step one is one or more of deionized water, anhydrous ethanol, acetone, and dilute hydrochloric acid.

4. The method for preparing a three-dimensional current collector for lithium metal batteries according to claim 3, characterized in that: The concentration of the dilute hydrochloric acid is 0.05-2 mol / L.

5. The method for preparing a three-dimensional current collector for lithium metal batteries according to claim 1, characterized in that: The temperature of the mixed solution in step two is 0-25℃.

6. The method for preparing a three-dimensional current collector for lithium metal batteries according to claim 1, characterized in that: The concentration of the dilute hydrochloric acid solution in step two is 0.5-1.5 mol / L.

7. The method for preparing a three-dimensional current collector for lithium metal batteries according to claim 1, characterized in that: The reaction time of the metal-based current collector in the mixed solution in step two is 0.5-6 hours.

8. The method for preparing a three-dimensional current collector for lithium metal batteries according to claim 1, characterized in that: The drying process described in step two is blower drying, with a temperature of 50-100℃ and a time of 15-24 hours.

9. The method for preparing a three-dimensional current collector for lithium metal batteries according to claim 1, characterized in that: The Zn salt mentioned in step four is zinc nitrate hexahydrate, zinc acetate, or zinc chloride.

10. The method for preparing a three-dimensional current collector for lithium metal batteries according to claim 1, characterized in that: The drying method described in step five is vacuum drying, with a temperature of 50-100℃.

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