Method for large-scale preparation of ultrathin lithium negative electrode

Abstract

The invention belongs to the technical field of lithium batteries, and particularly relates to a large-scale preparation method of an ultrathin lithium negative electrode, which comprises the following steps: preparing lithium metal into lithium powder by an emulsion method, a vacuum distillation method, an ultrasonication method, a mechanical pulverization method or a chemical deposition method; the method comprises the following steps: uniformly dispersing lithium powder and a two-dimensional material in solvents with similar boiling points or the same solvent respectively to form a lithium powder dispersion liquid and a two-dimensional material dispersion liquid; the two-dimensional material dispersion liquid and the lithium powder dispersion liquid are mixed in a crossed mode and coated on a substrate, and a lithium powder-two-dimensional material composite film is obtained; independently and rotationally spraying a layer of anti-lithium dendrite dispersion liquid or lithium-loving material dispersion liquid on the surface of the lithium powder-two-dimensional material composite film; and drying the pole piece to remove the solution, and rolling the membrane material to obtain the ultrathin lithium negative electrode. Compared with the prior art, large-scale rapid continuous production and low-temperature production can be realized; the obtained composite film is provided with a surface protection layer, can be temporarily stable in air, and is convenient for direct cutting application.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of lithium batteries, and particularly relates to a method for large-scale preparation of an ultrathin lithium negative electrode. BACKGROUND

[0002] Conventional lithium metal negative electrode preparation methods include coating or calendering, wherein coating is to coat pure lithium on the surface of a substrate after melting to form a lithium metal negative electrode film; and calendering is to gradually thin the thickness of lithium metal by adjusting the gap between the rollers from large to small. The thin film prepared by these methods is difficult to achieve an ultrathin thickness of several microns, and is prone to cracking and oxidation problems. Accordingly, a method of pouring graphene material into molten lithium and forming a film is adopted by Professor Cui Yi, which can obtain an ultrathin lithium metal negative electrode, but still has several technical problems.

[0003] Specifically, the coating method is prone to cause lithium metal volatilization loss and substrate thermal degradation during high-temperature melting, increasing production cost, and the molten lithium needs anhydrous and oxygen-free environment and additional energy to maintain the molten state of lithium; the calendering method can achieve thickness thinning, but uneven roller pressure can cause stress concentration on the surface of the thin film, causing micro-cracks and thickness fluctuations, and reducing the yield. Neither the coating method nor the calendering method can achieve large-scale preparation. The graphene reinforcement method can improve the mechanical strength and thickness accuracy of the thin film, but the method faces challenges such as complex process control, low efficiency and high material cost in large-scale production, which limits its commercial application. Moreover, the preparation of porous graphene or other porous two-dimensional materials requires additives such as pore-forming agents, which is low in efficiency and high in cost, and cannot be produced continuously.

[0004] Alternative solutions such as electrodeposition or vacuum evaporation have also been tried in the prior art, but these methods also have problems such as high equipment requirements, high energy consumption, and poor adhesion of the thin film, which cannot meet the demand for large-scale preparation. Therefore, it is urgent to develop an innovative method for efficiently and stably producing ultrathin lithium metal negative electrodes at low cost.

[0005] Therefore, the application aims to provide a method for large-scale preparation of an ultrathin lithium negative electrode, which can obtain a uniformly dispersed two-dimensional material lithium powder composite film by using a two-dimensional material dispersion liquid and a lithium powder dispersion liquid for double-axis (double-nozzle) rotary spraying, and spray a single lithium dendrite prevention layer on the last layer to prevent the lithium powder from contacting the external atmosphere, facilitating subsequent operation. SUMMARY

[0006] In view of the deficiencies of the prior art, a method for large-scale preparation of an ultrathin lithium negative electrode is provided, which can obtain a uniformly dispersed two-dimensional material lithium powder composite film by using a two-dimensional material dispersion liquid and a lithium powder dispersion liquid for double-axis (double-nozzle) rotary spraying, and spray a single lithium dendrite prevention layer on the last layer to prevent the lithium powder from contacting the external atmosphere, facilitating subsequent operation.

[0007] In order to solve the above problems and achieve the above purposes, the technical scheme of the present application is as follows:

[0008] A method for mass production of ultra-thin lithium negative electrode, comprising the following steps:

[0009] Firstly, lithium powder and two-dimensional material are uniformly dispersed in solvents with similar boiling points or the same solvent respectively to form lithium powder dispersion and two-dimensional material dispersion;

[0010] Secondly, the two-dimensional material dispersion and the lithium powder dispersion are sprayed on the substrate by double-axis rotation to obtain a lithium powder-two-dimensional material composite film; the thickness of the electrode sheet can be adjusted by time and rotation speed, and the lithium content can be adjusted by adjusting the spraying rate and the concentration of lithium in the raw material.

[0011] Thirdly, a layer of lithium dendrite prevention material dispersion or lithiumophilic material dispersion is separately sprayed on the surface of the lithium powder-two-dimensional material composite film;

[0012] Fourthly, the electrode sheet is dried to remove the solution, and the film material is rolled to obtain an ultra-thin lithium negative electrode.

[0013] As an improvement of the method for mass production of ultra-thin lithium negative electrode, the two-dimensional material is at least one of graphene, MXene, molybdenum sulfide, black scale and boron nitride (BN), or a mixture of two-dimensional non-conductive material and conductive material, the two-dimensional conductive material includes at least one of graphene, MXene, new two-dimensional polyaniline (2DPANI), and the two-dimensional non-conductive material includes at least one of molybdenum sulfide, black scale, gadolinium oxide (Gd2O5), and boron nitride (BN). The two-dimensional material such as graphene can play the roles of conducting electricity, fixing lithium powder, providing a skeleton for lithium metal deposition, and inhibiting expansion.

[0014] As an improvement of the method for mass production of ultra-thin lithium negative electrode, the MXene is at least one of Ti2CT x ,TiNbCT x ,Ti3CN x T x ,Ta4C3T x ,Nb2CT x ,V2CT x ,Nb4C3T x ,Mo2CT x ,(Nb 0.8 Ti 0.2 )4C3T x ,(Nb 0.8 Zr 0.2 )4C3T x ,Zr3C2T x and Hf3C2T x ) among which T xThe terminal representing the surface can be a combination of various functional groups such as OH, O, F, Cl, Br, etc.

[0015] As an improvement of the method for mass production of ultra-thin lithium negative electrode of the present application, the solvent in the first step is at least one of lipids, ethers, N-methyl pyrrolidone, vegetable oil and alkanes; the lipid is at least one of ethylene carbonate (EC), dimethyl carbonate (DMC), diethyl carbonate (DEC), the ether is dimethyl ether (DME), and the alkane is at least one of pentane, hexane, heptane, octane, nonane, decane or its isomers.

[0016] As an improvement of the method for mass production of ultra-thin lithium negative electrode of the present application, the two-dimensional material dispersion liquid can add a dispersant, and the dispersant is at least one of polyvinylpyrrolidone (PVP), sodium dodecylbenzenesulfonate (SDBS), sodium lignosulfonate (SLS), polyvinyl alcohol (PVA), polyethylene oxide, polyacrylic acid, polymethacrylic acid, and polyacrylamide.

[0017] As an improvement of the method for mass production of ultra-thin lithium negative electrode of the present application, the lithium dendrite prevention material includes one of fluoride, oxide and polymer, wherein the fluoride is at least one of lithium fluoride, tin fluoride, antimony fluoride, aluminum fluoride, zinc fluoride, zirconium fluoride, copper fluoride, bismuth fluoride, silver fluoride and manganese fluoride, the oxide is at least one of lithium oxide, tin oxide, antimony oxide, aluminum oxide, zinc oxide, zirconium oxide, copper oxide, bismuth oxide, silver oxide and manganese oxide, and the polymer is at least one of PEO, PAA, PVDF-HFP, PAN, PVC and PMMA.

[0018] As an improvement of the method for mass production of ultra-thin lithium negative electrode of the present application, the lithiumophilic material is oxide, metal powder and other compounds with functional groups capable of combining with lithium metal, wherein the oxide is at least one of lithium oxide, tin oxide, antimony oxide, aluminum oxide, zinc oxide, zirconium oxide, copper oxide, bismuth oxide, silver oxide and cobalt oxide; the metal powder is at least one of tin, copper, zinc, zirconium, silver, indium, gallium and aluminum, and the other compound is at least one of organic macromolecules, high molecular compounds with hydroxyl or ketone functional groups, nitrogen or sulfur or phosphorus doped carbon materials, 1,3,5-tri(p-formylphenyl)benzene-covalent organic framework (TFPB-COF) and metal organic framework (MOF).

[0019] As an improvement of the method for mass production of ultra-thin lithium negative electrode of the present application, the lithium dendrite prevention material or the lithiumophilic material is pre-loaded on the two-dimensional material, or is sprayed to form a film at the same time with lithium powder and two-dimensional material through a third spray head.

[0020] As an improvement of the method for mass production of ultra-thin lithium negative electrode of the present application, the thickness of the lithium powder-two-dimensional material composite film is 1-50 microns, the mass concentration of the two-dimensional material dispersion is 0.1-5%, the mass concentration of the lithium powder dispersion is 0.1-10%, the spraying time in the second step is 0.1-10 hours, the rotation speed is 5-2000 rpm, the drying temperature is 30-150℃, and the gas pressure is 10 Pa to normal pressure.

[0021] As an improvement of the method for mass production of ultra-thin lithium negative electrode of the present application, the cross-mixing coating is double-axis rotary spraying, or blade coating or spin coating to form a film. Preferably, it is double-axis rotary spraying. Double-axis rotary spraying is not spin coating, which is to spread the solution uniformly on the surface of the substrate by centrifugal force to form a film.

[0022] As an improvement of the method for mass production of ultra-thin lithium negative electrode of the present application, the lithium powder is prepared by emulsion method, vacuum distillation method, ultrasonic crushing method, mechanical crushing method or chemical deposition method.

[0023] Compared with the prior art, the present application uses two-dimensional material dispersion and lithium powder dispersion for cross-mixing coating, preferably double-axis (double-nozzle) rotary spraying, to obtain a uniformly dispersed two-dimensional material lithium powder composite film. A single lithium dendrite prevention layer or a lithiumophilic material layer is sprayed on the last layer to prevent the lithium powder from contacting the external atmosphere, facilitating subsequent operation.

[0024] The present application has at least the following effects:

[0025] First, the thickness can be controlled by the material dispersion concentration, time, rotation speed, etc.

[0026] Second, the double-axis rotary spraying can effectively mix and dry in situ, reducing agglomeration. Double-axis rotary spraying can be blade coating, spin coating, or other cross-mixing spraying methods.

[0027] Third, solid lithium powder is used instead of molten liquid lithium, reducing energy consumption and improving safety during preparation.

[0028] Fourth, the two-dimensional material can tightly adhere to the surface of the lithium powder after drying, forming a closed space. Lithium powder has two morphologies, spherical and irregular flaky. Using spherical lithium powder can provide more buffer space, and using flaky lithium powder can provide a denser structure.

[0029] Fifth, the two-dimensional material surface can also load some functional particles, further improving the practicality of the lithium negative electrode.

[0030] Sixth, the present application can be mass rapid continuous production, low temperature production; the resulting composite film has a surface protective layer, can be short-term stable in air, direct cutting application is facilitated. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 Structure diagram of the biaxial rotary spraying device used in the present application. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical scheme and advantages of the embodiments of the present application more clear, the technical scheme in the embodiments of the present application will be clearly and completely described below. Obviously, the described embodiments are some embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0033] The experimental methods used in the embodiments of the present application are all conventional methods unless otherwise specified.

[0034] In the following examples and comparative examples, all the raw materials can be prepared and synthesized by conventional methods or purchased unless otherwise specified.

[0035] Example 1

[0036] Figure 1 The diagram of the biaxial rotary spraying device used in the present application includes a rotating shaft 1, a spraying container A 2 linked with the rotating shaft 1, a second spraying container B 3, a first spraying head 4 arranged on the spraying container A 2, a second spraying head 5 arranged on the spraying container B 3, a bottom plate 6 located below the first spraying head 4 and the second spraying head 5, and a heating device 7 located below the bottom plate 6. An electrode substrate 8 is placed on the bottom plate 6. The rotating shaft 1 can move left and right (the rotating shaft 1 is connected with a left and right moving mechanism, not shown in the figure) with the first spraying head 4 and the second spraying head 5, and the electrode substrate 8 can move left and right (driven by another left and right moving mechanism, not shown in the figure).

[0037] The present application provides a method for mass production of ultra-thin lithium negative electrode, which includes graphene, lithium powder, lithiumophilic substance, lithium dendrite prevention particles and other raw materials, which specifically includes the following steps:

[0038] Firstly, graphene and polyethylene oxide are added into DMC with a mass ratio of 10:1 and 1:50000, and ultrasonic stirring is performed for 1h (ultrasonic rod, ultrasonic frequency 40KHz, power 600W, same below). Then, tin oxide nano-powder with a mass ratio of 5:1 to graphene (tin oxide has lithiumophilic and lithium dendrite prevention effects) is added and ultrasonic stirring is performed for 1h to form a first dispersion liquid. Lithium powder with a mass ratio of 2:1 to graphene is added into a second portion of DMC and ultrasonic stirring is performed for 1h to form a second dispersion liquid.

[0039] Second step, the two dispersions prepared in step 1 were added to the spraying containers A and B respectively at a small flow rate, and sprayed at a flow rate of 1 ml / min, a rotation speed of 300 rpm, a nozzle moving speed of 10 mm / min, a substrate moving speed of 10 mm / min, a substrate drying temperature of 80°, and an air pressure in the spraying chamber of 100 pa. Spraying was performed for 1 h.

[0040] Third step, a solution of antimony fluoride and DMC was then prepared at a ratio of 1:50, ultrasonically stirred for 1 h, and then added to a third spraying container to spray the film prepared in step 2 at a rate of 2 ml / min, a rotation speed of 300 rpm, a spraying time of 0.5 h, a substrate drying temperature of 80°, and an air pressure in the spraying chamber of 100 pa.

[0041] Fourth step, the dried film material was rolled at a pressure of 1 MPa.

[0042] In this embodiment, the lithium powder used was prepared by an emulsion method.

[0043] The film prepared in this embodiment had a thickness of about 3.2 microns, a specific capacity of the negative electrode material of 1386 mAh / g, a first efficiency of 90.5%, and a cycle life of the positive electrode LFP at 0.5 C of 772 cycles.

[0044] Example 2

[0045] The present embodiment provides a method for large-scale preparation of an ultrathin lithium negative electrode, which comprises graphene, lithium powder, lithiumophilic substances, and the like, and specifically comprises the following steps:

[0046] First step, graphene and polyethylene oxide were added to DMC at a mass ratio of 10:1 and 1:50000, respectively, and ultrasonically stirred for 1 h (ultrasonic rod, ultrasonic frequency 40 KHz, power 600 W, same below). Finally, tin oxide nano-powder was added at a mass ratio of 5:1 to graphene, and ultrasonically stirred for 1 h to form a first dispersion. Lithium powder was added to DMC at a mass ratio of 2:1 and ultrasonically stirred for 1 h to form a second dispersion.

[0047] Second step, the two dispersions prepared in step 1 were added to the spraying containers A and B respectively at a small flow rate, and sprayed at a flow rate of 1 ml / min, a rotation speed of 300 rpm, a nozzle moving speed of 10 mm / min, a substrate moving speed of 10 mm / min, a substrate drying temperature of 80°, and an air pressure in the spraying chamber of 100 pa. Spraying was performed for 1 h.

[0048] Third step, the dried film material was rolled at a pressure of 1 MPa.

[0049] In the present embodiment, the lithium powder is prepared by vacuum distillation.

[0050] The film prepared in the present embodiment has a thickness of about 2.8 microns, the specific capacity of the negative electrode material is 1386 mAh / g, the initial efficiency is 89.5%, and the cycle life of the positive electrode as LFP under 0.5C is 479 cycles.

[0051] Example 3

[0052] The present comparative example provides a method for large-scale preparation of an ultrathin lithium negative electrode, which includes graphene, lithium powder, and other raw materials, and removes the tin oxide nano powder in the first step of Example 2. The lithium powder is prepared by ultrasonic crushing. The rest is the same as Example 2 and will not be repeated here.

[0053] The film prepared in the present example has a thickness of about 2.7 microns, the specific capacity of the negative electrode material is 1386 mAh / g, the initial efficiency is 87.3%, and the cycle life of the positive electrode as LFP under 0.5C is 435 cycles.

[0054] Example 4

[0055] The present embodiment provides a method for large-scale preparation of an ultrathin lithium negative electrode, which includes MXene (Ti2CT x ), black scale, lithium powder, lithiumophilic substance, lithium dendrite prevention particles, and other raw materials. MXene (Ti2CT x ) is used to replace graphene, and the lithium powder is prepared by mechanical crushing. The rest is the same as Example 1 and will not be repeated here.

[0056] The film prepared in the present embodiment has a thickness of about 3.2 microns, the specific capacity of the negative electrode material is 1386 mAh / g, the initial efficiency is 88.9%, and the cycle life of the positive electrode as LFP under 0.5C is 612 cycles.

[0057] Example 5

[0058] The present comparative example provides a method for large-scale preparation of an ultrathin lithium negative electrode, which includes graphene, lithium powder, tin oxide nano powder, lithium dendrite prevention particles, and other raw materials. The polyethylene oxide in the first step of Example 1 is removed, and the lithium powder is prepared by chemical deposition. The rest is the same as Example 1 and will not be repeated here.

[0059] The film prepared in the present example has a thickness of about 2.7 microns, the specific capacity of the negative electrode material is 1386 mAh / g, the initial efficiency is 88.2%, and the cycle life of the positive electrode as LFP under 0.5C is 478 cycles.

[0060] Example 6

[0061] The comparative example provides a method for large-scale preparation of an ultra-thin lithium negative electrode, which includes graphene, lithium powder, tin oxide nano-powder, lithium dendrite prevention particles and the like raw materials, and specifically includes the following steps:

[0062] In the first step, graphene and polyethylene oxide are added to DMC in a mass ratio of 10:1, and graphene is added to DMC in a mass ratio of 1:50000, and ultrasonic stirring is performed for 1h (ultrasonic rod, ultrasonic frequency 40KHz, power 600W, same below). Finally, tin oxide nano-powder is added in a mass ratio of 5:1 with graphene, ultrasonic stirring is performed for 1h, and a first dispersion liquid is formed. Lithium powder is added in a mass ratio of 2:1 with the above graphene in a second portion of DMC, and ultrasonic stirring is performed for 1h to form a second dispersion liquid.

[0063] In the second step, the two dispersion liquids prepared in step 1 are mixed in a ratio of 1:1, and antimony fluoride is added, the mass ratio of antimony fluoride to the mixed DMC is 1:50, ultrasonic stirring is performed for 1h to form a mixed liquid, the mixed liquid is taken on a doctor blade, and a film is uniformly scraped and coated, the scraping thickness is 30um, the scraping temperature is 25 degrees, the doctor blade is dried to obtain a thin film, and the drying temperature is 80°.

[0064] In the third step, the dried film material is rolled at a pressure of 1MPa.

[0065] The film thickness prepared in this example is about 4.8 microns, the specific capacity of the negative electrode material is 1386mAh / g, the initial efficiency is 78.3%, and the cycle life of the positive electrode LFP at 0.5C is 494 cycles.

[0066] Example 7

[0067] In the second step and the third step of the modified example 1, the rotation speed is modified to 5rpm, and the rest is the same as example 1, which will not be repeated here.

[0068] The film thickness prepared in this example is about 3.9 microns, the specific capacity of the negative electrode material is 1386mAh / g, the initial efficiency is 75.3%, and the cycle life of the positive electrode LFP at 0.5C is 378 cycles.

[0069] Example 8

[0070] In the second step and the third step of the modified example 1, the rotation speed is modified to 2000rpm, and the rest is the same as example 1, which will not be repeated here.

[0071] The film thickness prepared in this example is about 5.9 microns, the specific capacity of the negative electrode material is 1386mAh / g, the initial efficiency is 86.3%, and the cycle life of the positive electrode LFP at 0.5C is 571 cycles.

[0072] Example 9

[0073] The mass ratio of graphene to DMC in the first step of the modified embodiment 1 is 1:5000, and the rest is the same as embodiment 1, which will not be repeated here.

[0074] The film prepared in this embodiment has a thickness of about 46.3 microns, a specific capacity of the negative electrode material of 1386 mAh / g, a first efficiency of 87.1%, and a cycle life of the positive electrode LFP at 0.5C of 595 cycles.

[0075] It can be seen that after adding lithiumophilic substances, lithium dendrite prevention particles and other raw materials to the lithium negative electrode in example 1, the test data obtained is relatively optimal; the decrease in the first efficiency in examples 2 and 3 is due to the consumption of lithium negative electrode for forming an additional SEI layer, and the decrease in cycle life reflects the decrease in stability of the negative electrode after the absence of lithiumophilic substances and lithium dendrite prevention layer; example 4 uses MXene and black scale two materials in combination to replace graphene, and also obtains an ultrathin lithium negative electrode, and the performance is slightly inferior to that of example 1; example 5 removes the dispersant compared with example 1, and the performance of the obtained thin film is poor; example 6 uses a scraping method to replace the double-shaft rotary spraying, and the performance of the obtained thin film is poor; example 7 adjusts the spraying speed to the lower limit, and the uniformity of the obtained thin film decreases, resulting in a decrease in performance; example 8 adjusts the spraying speed to the upper limit, and the quality of the obtained thin film is good; example 9 makes the film thickness to 46 microns, and the performance is good.

[0076] According to the disclosure and teaching of the above description, those skilled in the art of the present application can also make changes and modifications to the above embodiments. Therefore, the present application is not limited to the specific embodiments disclosed and described above, and some modifications and changes of the present application should also fall within the protection scope of the claims of the present application. In addition, although some specific terms are used in the present specification, these terms are only for convenience of explanation and do not constitute any limitation on the present application.

Claims

1. A method for large-scale preparation of ultrathin lithium anodes, characterized in that, Includes the following steps: The first step is to uniformly disperse lithium powder and two-dimensional materials in solvents with similar boiling points or in the same solvent to form lithium powder dispersion and two-dimensional material dispersion, respectively. The second step involves cross-mixing the two-dimensional material dispersion and the lithium powder dispersion and coating them onto the substrate to obtain a lithium powder-two-dimensional material composite film. The third step is to spin-spray a layer of anti-lithium dendrite material dispersion or lithium-affinity material dispersion onto the surface of the lithium powder-two-dimensional material composite film. The fourth step is to dry the electrode to remove the solution and roll-press the film to obtain an ultra-thin lithium anode.

2. The method for large-scale preparation of ultrathin lithium anodes according to claim 1, characterized in that, The two-dimensional material is at least one of graphene, MXene, molybdenum sulfide, black scale, and boron nitride (BN), or a mixture of two-dimensional non-conductive and conductive materials. The two-dimensional conductive material includes at least one of graphene, MXene, and novel two-dimensional polyaniline (2DPANI). The two-dimensional non-conductive material includes at least one of molybdenum sulfide, black scale, gadolinium oxide (Gd₂O₅), and boron nitride (BN). Specifically, MXene is Ti₂CT. x TiNbCT x Ti3CN x T x Ta4C3T x Nb2CT x V2CT x Nb4C3T x Mo2CT x 、(Nb 0.8 Ti 0.2 )4C3T x 、(Nb 0.8 Zr 0.2 )4C3T x Zr3C2T x and Hf3C2T x At least one of them, wherein T x The terminal of the surface is a combination of various functional groups such as OH, O, F, Cl, and Br.

3. The method for large-scale preparation of ultrathin lithium anodes according to claim 1, characterized in that: The solvent mentioned in the first step is at least one of lipids, ethers, N-methylpyrrolidone, vegetable oils, and alkanes; wherein the lipid is at least one of ethylene carbonate (EC), dimethyl carbonate (DMC), and diethyl carbonate (DEC), the ether is dimethyl ether (DME), and the alkanes are at least one of pentane, hexane, heptane, octane, nonane, decane, or their isomers.

4. The method for large-scale preparation of ultrathin lithium anodes according to claim 1, characterized in that: The two-dimensional material dispersion also includes a dispersant, which includes polyvinylpyrrolidone (PVP), sodium dodecylbenzene sulfonate (SDBS), sodium lignosulfonate (SLS), polyvinyl alcohol (PVA), polyethylene oxide, polyacrylic acid, polymethacrylic acid, and polyacrylamide.

5. The method for large-scale preparation of ultrathin lithium anodes according to claim 1, characterized in that: The anti-lithium dendrite material includes one of fluorides, oxides, and polymers. The fluoride is at least one of lithium fluoride, tin fluoride, antimony fluoride, aluminum fluoride, zinc fluoride, zirconium fluoride, copper fluoride, bismuth fluoride, silver fluoride, and manganese fluoride. The oxide is at least one of lithium oxide, tin oxide, antimony oxide, aluminum oxide, zinc oxide, zirconium oxide, copper oxide, bismuth oxide, silver oxide, and manganese oxide. The polymer is at least one of PEO, PAA, PVDF-HFP, PAN, PVC, and PMMA.

6. The method for large-scale preparation of ultrathin lithium anodes according to claim 1, characterized in that: The lithiophilic materials are oxides, metal powders, and other compounds with functional groups that can bind to lithium metal. The oxides are at least one of lithium oxide, tin oxide, antimony oxide, aluminum oxide, zinc oxide, zirconium oxide, copper oxide, bismuth oxide, silver oxide, and cobalt oxide. The metal powders are at least one of tin, copper, zinc, zirconium, silver, indium, gallium, and aluminum. The other compounds are at least one of organic macromolecules, polymers with hydroxyl or ketone functional groups, nitrogen, sulfur, or phosphorus doped carbon materials, 1,3,5-tris(p-formylphenyl)benzene-covalent organic framework (TFPB-COF), and metal-organic framework (MOF).

7. The method for large-scale preparation of ultrathin lithium anodes according to claim 6, characterized in that: Lithium dendrite-resistant or lithium-affinity materials are preloaded onto two-dimensional materials, or sprayed simultaneously with lithium powder and two-dimensional materials through a third nozzle to form a film.

8. The method for large-scale preparation of ultrathin lithium anodes according to claim 1, characterized in that: The thickness of the lithium powder-two-dimensional material composite film is 1 micrometer-50 micrometers, the mass concentration of the two-dimensional material dispersion is 0.1-5%, the mass concentration of the lithium powder dispersion is 0.1-10%, the spraying time in the second step is 0.1-10 hours, the rotation speed is 5-2000 rpm, the drying temperature is 30-150℃, and the air pressure is 10 Pa to atmospheric pressure.

9. The method for large-scale preparation of ultrathin lithium anodes according to claim 1, characterized in that: Cross-mix coating is achieved through biaxial rotary spraying, or by scraping or rotary smearing to form a film.

10. The method for large-scale preparation of ultrathin lithium anodes according to claim 1, characterized in that: Lithium powder is prepared by emulsion method, vacuum distillation method, ultrasonic crushing method, mechanical pulverization method or chemical deposition method.

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