Laser etching current collector applied to lithium metal negative electrode of solid-state battery

Abstract

The invention discloses a laser etching current collector applied to a lithium metal negative electrode of a solid-state battery, and relates to the technical field of solid-state batteries. Concave holes are formed in the surface of the current collector; the diameter of each concave hole is 10-50 nm, the depth of each concave hole is 30-80 nm, and the distance between every two adjacent concave holes is 10-50 nm. The concave hole is obtained by etching the metal copper layer of the current collector through purple picosecond laser; the method can be applied to a lithium metal negative electrode of a solid-state battery, and specifically comprises the following steps: in a dehumidification environment, rolling a lithium strip and a laser etching current collector in a rubber roller press so as to form the lithium metal negative electrode taking the laser etching current collector as a middle interlayer; tests show that the current collector has good peel strength and battery coulombic efficiency, the technical effect that the current collector is provided with a carbon coating layer can be achieved, meanwhile, the problem of wrinkles existing in an existing current collector during rolling in the preparation process is solved, and the production yield is increased.

Description

Technical Field

[0001] The present invention relates to the technical field of solid-state batteries, and specifically to a laser-etched current collector applied to the lithium metal anode of a solid-state battery. Background Art

[0002] Improving the battery energy density is of utmost importance. In existing solid-state batteries, a composite carbon-coated copper foil is used as the lithium metal anode, that is, a carbon-coated layer is provided on the surface of the current collector, and then a lithium strip and the carbon-coated functional current collector are pressed together through a rubber roller to form a lithium metal anode that can improve the energy density. However, there are many small bubbles on the surface of the lithium metal anode pressed by this method. During the winding process in the preparation process, there are wrinkles in the existing current collector, and the production yield is low. The reason is caused by the moisture in the carbon-coated slurry. Moreover, lithium metal is very reactive, and the lithium strip corresponding to the bubble position will be oxidized, turn black, and fail. At the same time, there are also problems such as low peel strength, poor bonding, and low Coulomb efficiency of the battery.

[0003] In summary, to solve the above problems, it is of great significance to provide a laser-etched current collector that has a tight bond, a high Coulomb efficiency of the battery, and can be applied to the lithium metal anode of a solid-state battery. Summary of the Invention

[0004] The purpose of the present invention is to provide a laser-etched current collector applied to the lithium metal anode of a solid-state battery to solve the problems raised in the prior art.

[0005] To achieve the above purpose, the present invention provides the following technical solutions:

[0006] A laser-etched current collector applied to the lithium metal anode of a solid-state battery, characterized in that: concave holes are provided on the surface of the current collector; the diameter of the concave holes is 10-50 nm, the depth is 30-80 nm, and the distance between the concave holes is 10-50 nm.

[0007] More preferably, the shape of the concave holes includes one with a narrow end and a wide end, long strip-shaped, circular, polygonal; preferably, it is water droplet-shaped.

[0008] More preferably, the regulation of the shape of the concave holes can be achieved by importing a laser program from a drawing, or by providing a template between the laser emission source and the current collector for regulation.

[0009] More preferably, the concave holes are obtained by ultraviolet picosecond laser etching of the metal copper layer on the surface of the current collector; during the laser etching process, the etching laser power is 18-22%, the laser frequency is 800 kHz, the engraving speed is 4000 mm / s, and the laser width is 0.008-0.010 mm.

[0010] More preferably, the current collector has a polymer film layer in the middle and a metal copper layer on each side; the polymer film layer includes one of a PET layer or a PP layer; the thickness of the polymer film layer is 4.5 ± 0.5 μm, and the thickness of the metal copper layer is 1 ± 0.1 μm.

[0011] More preferably, the application of the laser-etched current collector in the lithium metal anode of a solid-state battery includes the following steps: in a dehumidified environment, roll the lithium strip and the laser-etched current collector in a rubber roll press to form a lithium metal anode with the laser-etched current collector as the middle interlayer.

[0012] More preferably, during the rolling process, the dew point temperature is -50 to -70 °C, the rolling pressure is 8 to 12 T, and the speed is 18 to 20 m / min.

[0013] More preferably, the preparation method of the laser-etched current collector includes the following steps:

[0014] S1: Etch the metal copper layer of the current collector with ultraviolet picosecond laser to obtain a laser-etched functional current collector;

[0015] S2: Immerse the laser-etched functional current collector in a dopamine solution, stir at 40 to 45 °C for 3 to 4 h, take it out, rinse with absolute ethanol, and dry in a nitrogen atmosphere to obtain a functional current collector A;

[0016] S3: Add modified nano-aluminum oxide to acetonitrile and disperse it evenly, adjust the pH to 8 to 9 to obtain a slurry, spray the slurry on the surface of the functional current collector A with a thickness of 10 to 20 μm, and dry it at 70 to 80 °C under vacuum conditions to obtain a functional current collector B;

[0017] S4: Immerse the functional current collector B back into the dopamine solution, stir at 40 to 45 °C for 6 to 8 h, take it out, rinse with absolute ethanol, and dry in a nitrogen atmosphere to obtain the laser-etched current collector.

[0018] Among them, the dopamine solution includes the following raw materials: 1.2 to 1.5 g / L hydrochloric acid dopamine, 15 to 17 g / L piperidine, and the solvent is absolute ethanol; the mass ratio of the modified nano-aluminum oxide to acetonitrile is 1:0.5 to 1.

[0019] More preferably, the preparation method of the modified alumina includes the following steps:

[0020] (1) Add nano-aluminum oxide to an ethanol solution and disperse it evenly by ultrasonic wave, add 3-(2,3-epoxypropoxy)propyltrimethoxysilane, stir at 40 to 50 °C for 1 to 2 h, filter, wash, and dry to obtain epoxidized nano-aluminum oxide;

[0021] (2) Ultrasonically disperse the epoxidized nano-aluminum oxide in anhydrous tetrahydrofuran, add tetra-arm polyethylene glycol amine and boron trifluoride, and stir at 40-50 °C for 2-3 h. Filter, wash, and dry to obtain polyethylene glycol-modified nano-aluminum oxide.

[0022] (3) Add the polyethylene glycol-modified nano-aluminum oxide to deionized water and ultrasonically disperse it evenly. Add tetrafluoropropionic acid and an activator, and stir at 50-60 °C for 4-6 h to obtain modified nano-aluminum oxide.

[0023] Among them, the epoxidized nano-aluminum oxide comprises the following raw materials in parts by mass: 7-9 parts of nano-aluminum oxide, 50-60 parts of 70% ethanol solution, and 1-2 parts of 3-(2,3-epoxypropoxy)propyltrimethoxysilane;

[0024] The polyethylene glycol-modified nano-aluminum oxide comprises the following raw materials in parts by mass: 7-9 parts of epoxidized nano-aluminum oxide, 70-80 parts of anhydrous tetrahydrofuran, 25-30 parts of tetra-arm polyethylene glycol amine, and 0.06-0.08 parts of boron trifluoride;

[0025] The modified nano-aluminum oxide comprises the following raw materials in parts by mass: 15-17 parts of polyethylene glycol-modified nano-aluminum oxide, 30-40 parts of deionized water, 0.5-0.75 parts of tetrafluoropropionic acid, and 1-1.5 parts of activator.

[0026] More preferably, the molecular weight of the tetra-arm polyethylene glycol amine is 2000-5000; the activator comprises 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide and N-hydroxysuccinimide with a mass ratio of 1:1-1.5; the particle size of the nano-aluminum oxide is 20 nm.

[0027] More preferably, during the laser etching process, an active region corresponding to the lithium strip is formed in the current collector and laser etching is performed, and the current collector substrate cannot be transparent during the etching process.

[0028] Compared with the prior art, the beneficial effects of this application are as follows:

[0029] (1) In the present invention, ultraviolet picosecond is used to laser-etch the current collector, and pits are etched on the surface, thereby improving the peeling force between the lithium strip and the foil, preventing the negative active material from falling off the surface of the current collector during charge and discharge, and increasing the stability of the battery negative electrode; at the same time, the specific surface area of the copper foil current collector is also significantly increased, providing more deposition sites for lithium ions, which helps to disperse the current density and make the lithium ions more uniform during deposition, thereby inhibiting the growth of lithium dendrites and increasing the Coulomb efficiency of the battery. The pit shape is preferably a water droplet shape, and the peeling force after rolling is stronger.

[0030] Compared with coating carbon on the surface of the current collector, the bubble problem is significantly solved, and the oxidation failure of the lithium strip is avoided. By means of etching, the present invention reduces the amount of copper used, effectively improves the battery energy density, and meets the technical effect of having a carbon coating layer.

[0031] (2) The present invention also pre-treats the surface of the etched copper foil current collector to further enhance the interfacial effect: Polydopamine contains a large number of phenolic hydroxyl and amino functional groups, and can firmly adhere to the surface of the copper foil through in-situ polymerization, enhancing the binding property; at the same time, when lithium ions are deposited, the lithium ions will react with the ortho-phenol structure in polydopamine, converting the phenolic hydroxyl group into a carbonyl group and generating a lithium ion complex carbonyl structure, which can serve as the nucleation site for subsequent lithium deposition, helping to disperse the current density, inhibit the growth of lithium dendrites, and increase the Coulombic efficiency of the battery. Nano-aluminum oxide has a high Young's modulus and can act as a physical barrier to inhibit the penetration and growth of lithium dendrites; in addition, nano-aluminum oxide, as a Lewis acid, can combine with the anions of lithium salts, thereby improving the transport efficiency of lithium ions and further inhibiting the formation of lithium dendrites. To further enhance its effect, the present invention grafts and introduces tetrafluoropropionic acid to further weaken the binding between anions and lithium ions and enhance the transport efficiency; by grafting nano-aluminum oxide and four-arm-polyethylene glycol-amine, its dispersibility can be improved. Polyethylene glycol has good softness and can adapt to the volume expansion of lithium metal during the cycling process, increasing the battery energy density and improving the Coulombic efficiency of the battery. The amino structure in polyethylene glycol can also form hydrogen bonds with the groups in the polydopamine structure, further enhancing the binding property.

[0032] (3) The present invention adopts a structure of attaching a layer of polydopamine layer, a layer of polyethylene glycol layer loaded with modified alumina, and a layer of polydopamine layer on the surface of the copper foil current collector. Such a structure helps to multiply inhibit the growth of lithium dendrites while ensuring the binding property, improve the transport efficiency of lithium ions, and thus improve the Coulombic cycle efficiency of the battery. Description of the Drawings

[0033] Figure 1 It is an image of the laser-etched current collector of Example 1 of the present invention magnified 500 times;

[0034] Figure 2 It is an image of the laser-etched current collector of Example 2 of the present invention magnified 500 times;

[0035] Figure 3 It is an image of the laser-etched current collector of Example 3 of the present invention magnified 500 times;

[0036] Figure 4 It is an image of the laser-etched current collector of Comparative Example 2 of the present invention magnified 500 times;

[0037] Figure 5This is the image of the lithium metal anode obtained by roll-pressing the laser-etched current collector and lithium strip prepared in Comparative Example 1 of the present invention. Detailed implementation mode

[0038] Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

[0039] It should be noted that there are no special restrictions on the purchasing manufacturers of all raw materials involved in the present invention. Exemplarily, they include: nano-aluminum oxide with a particle size of 20 nm; 3-(2,3-epoxypropoxy)propyltrimethoxysilane with a CAS number of 2530-83-8; four-arm polyethylene glycol-amine with a molecular weight of 2000-5000, provided by Zhengzhou Huiju Chemical Co., Ltd.; tetrafluoropropionic acid with a CAS number of 756-09-2; the remaining raw materials used in the other examples and comparative examples but not mentioned above are all commercially available, and the parts are by mass.

[0040] More preferably, the laser-etched current collectors prepared by the respective examples and comparative examples are used to prepare a lithium metal anode, which specifically includes the following steps: at a dew point temperature of -50 to -70, an 18-μm lithium strip and the laser-etched current collector are roll-pressed in a rubber roll press with the following parameters: the roll-pressing pressure is 10 T, and the speed is 20 m / min, thereby forming a lithium metal anode with the laser-etched current collector as the intermediate interlayer.

[0041] More preferably, in each of the examples and comparative examples, the polymer in the middle of the current collector is PP.

[0042] Example 1: The preparation of the laser-etched current collector specifically includes the following steps:

[0043] The metal copper layer of the current collector is etched by ultraviolet picosecond laser with the following parameters: the etching laser power is 22%, the laser width is 0.010 mm, the laser frequency is 800 kHz, the engraving speed is 4000 mm / s, the etching shape is a water droplet shape, the diameter of the water droplet shape is 50 nm, the etching depth is 80 nm, and the spacing of the water droplet shapes is 15 nm, to obtain the laser-etched current collector.

[0044] Example 2: The preparation of the laser-etched current collector specifically includes the following steps:

[0045] The metal copper layer of the current collector is etched by ultraviolet picosecond laser with the following parameters: the etching laser power is 18%, the laser width is 0.008 mm, the laser frequency is 800 kHz, the engraving speed is 4000 mm / s, the etching shape is a water droplet shape, the diameter of the water droplet shape is 10 nm, the etching depth is 30 nm, and the spacing of the water droplet shapes is 15 nm, to obtain the laser-etched current collector.

[0046] Example 3: The preparation of the laser-etched current collector specifically includes the following steps:

[0047] Etch the metal copper layer of the current collector with an ultraviolet picosecond laser. The parameters are as follows: the etching laser power is 20%, the laser width is 0.009 mm, the laser frequency is 800 kHz, the scribing speed is 4000 mm / s, the etching shape is a water droplet shape, the diameter of the water droplet shape is 30 nm, the etching depth is 50 nm, and the spacing of the water droplet shapes is 15 nm to obtain a laser-etched current collector.

[0048] Example 4: The preparation of the laser-etched current collector specifically includes the following steps:

[0049] Etch the metal copper layer of the current collector with an ultraviolet picosecond laser. The parameters are as follows: the etching laser power is 22%, the laser width is 0.010 mm, the laser frequency is 800 kHz, the scribing speed is 4000 mm / s, the etching shape is a spherical shape, the diameter is 50 nm, the etching depth is 80 nm, and the spacing of the spherical shapes is 15 nm to obtain a laser-etched current collector.

[0050] Comparative Example 1: Coating a carbon paste on the surface of the current collector. Specifically, the carbon paste is coated on the surface of the functional current collector by gravure coating, and the thickness after drying is 1 μm to obtain a carbon-coated functional current collector;

[0051] Among them, the carbon paste includes the following raw materials, by mass fraction: 2.2% conductive carbon black, 1.9% conductive graphite, 3.7% PAA, and the rest is deionized water.

[0052] Comparative Example 2: Based on Example 1, further increase the power of laser etching. Specifically:

[0053] Etch the metal copper layer of the current collector with an ultraviolet picosecond laser. The parameters are as follows: the etching laser power is 27%, the laser width is 0.010 mm, the laser frequency is 800 kHz, the scribing speed is 4000 mm / s, the etching shape is a water droplet shape, the diameter of the water droplet shape is 50 nm, the etching depth is 100 nm, and the spacing of the water droplet shapes is 15 nm to obtain a laser-etched current collector.

[0054] Example 5: Based on Example 1, the preparation of the laser-etched current collector specifically includes the following steps:

[0055] S1: Etch the metal copper layer of the current collector with an ultraviolet picosecond laser. The parameters are as follows: the etching laser power is 22%, the laser width is 0.010 mm, the laser frequency is 800 kHz, the scribing speed is 4000 mm / s, the etching shape is a water droplet shape, the diameter of the water droplet shape is 50 nm, the etching depth is 80 nm, and the spacing of the water droplet shapes is 15 nm to obtain a laser-etched functional current collector;

[0056] S2: Immerse the laser-etched functional current collector in dopamine solution, stir at 40 °C for 3.5 h, take it out, rinse with absolute ethanol, and dry it under a nitrogen atmosphere to obtain the functional current collector A;

[0057] S3: Add the modified nano-aluminum oxide to acetonitrile and disperse it evenly, adjust the pH to 8.5 to obtain a slurry. Spray the slurry on the surface of the functional current collector A with a thickness of 15 μm, and dry it at 75 °C under vacuum conditions to obtain the functional current collector B;

[0058] S4: Immerse the functional current collector B back into the dopamine solution, stir at 40 °C for 7 h, take it out, rinse with absolute ethanol, and dry it under a nitrogen atmosphere to obtain the laser-etched current collector.

[0059] Among them, the dopamine solution includes the following raw materials: 1.3 g / L hydrochloric acid dopamine, 16 g / L piperidine, and the solvent is absolute ethanol; the mass ratio of the modified nano-aluminum oxide to acetonitrile is 1:0.7.

[0060] Among them, the preparation method of the modified nano-aluminum oxide includes the following steps: (1) Add 8 parts of nano-aluminum oxide to 55 parts of 70% ethanol solution and disperse it evenly by ultrasonic wave. Add 1.5 parts of 3-(2,3-epoxypropoxy)propyltrimethoxysilane, stir at 45 °C for 1.5 h, filter, wash, and dry to obtain epoxidized nano-aluminum oxide; (2) Ultrasonically disperse 8 parts of epoxidized nano-aluminum oxide in 75 parts of anhydrous tetrahydrofuran, add 27 parts of tetra-arm polyethylene glycol-amine and 0.07 part of boron trifluoride, stir at 45 °C for 2.5 h, filter, wash, and dry to obtain polyethylene glycol-modified nano-aluminum oxide; (3) Add 16 parts of polyethylene glycol-modified nano-aluminum oxide to 35 parts of deionized water and disperse it evenly by ultrasonic wave. Add 0.75 part of tetrafluoropropionic acid and 1.5 parts of activator, stir at 55 °C for 5 h to obtain the modified nano-aluminum oxide.

[0061] Comparative Example 3: Based on Example 5, without introducing modified alumina, and the rest of the processes remain unchanged. Specifically as follows:

[0062] S1: Etch the metal copper layer of the current collector by ultraviolet picosecond laser with the following parameters: the etching laser power is 22%, the laser width is 0.010 mm, the laser frequency is 800 kHz, the engraving speed is 4000 mm / s, the etching shape is a water droplet shape, the diameter of the water droplet shape is 50 nm, the etching depth is 80 nm, and the spacing of the water droplet shapes is 15 nm to obtain the laser-etched functional current collector;

[0063] S2: Immerse the laser-etched functional current collector in dopamine solution, stir at 40 °C for 10.5 h, take it out, rinse with absolute ethanol, and dry it under a nitrogen atmosphere to obtain the laser-etched current collector.

[0064] Among them, the dopamine solution comprises the following raw materials: 1.3 g / L dopamine hydrochloride, 16 g / L piperidine, and the solvent is anhydrous ethanol.

[0065] Comparative Example 4: Based on Example 5, a layer of modified nano-aluminum oxide was directly attached to the surface of the copper foil, and the remaining processes remained unchanged, specifically as follows:

[0066] S1: The metal copper layer of the current collector was etched by ultraviolet picosecond laser with the following parameters: the etching laser power was 22%, the laser width was 0.010 mm, the laser frequency was 800 kHz, the engraving speed was 4000 mm / s, the etching shape was a water droplet shape, the diameter of the water droplet shape was 50 nm, the etching depth was 80 nm, and the spacing of the water droplet shapes was 15 nm to obtain a laser-etched functional current collector;

[0067] S2: The modified nano-aluminum oxide was added to acetonitrile and dispersed evenly, and the pH was adjusted to 8.5 to obtain a slurry. The slurry was sprayed on the surface of the laser-etched functional current collector with a thickness of 15 μm and dried at 75 °C under vacuum conditions to obtain a functional current collector B;

[0068] S3: The functional current collector B was immersed in the dopamine solution, stirred at 40 °C for 7 h, taken out, rinsed with anhydrous ethanol, and dried under a nitrogen atmosphere to obtain a laser-etched current collector.

[0069] Among them, the dopamine solution comprises the following raw materials: 1.3 g / L dopamine hydrochloride, 16 g / L piperidine, and the solvent is anhydrous ethanol; the mass ratio of the modified nano-aluminum oxide to acetonitrile is 1:0.7.

[0070] Among them, the preparation method of the modified nano-aluminum oxide comprises the following steps: (1) 8 parts of nano-aluminum oxide were added to 55 parts of 70% ethanol solution and ultrasonically dispersed evenly, 1.5 parts of 3-(2,3-epoxypropoxy)propyltrimethoxysilane were added, and stirred at 45 °C for 1.5 h, filtered, washed, and dried to obtain epoxy nano-aluminum oxide; (2) 8 parts of epoxy nano-aluminum oxide were ultrasonically dispersed in 75 parts of anhydrous tetrahydrofuran, 27 parts of four-arm-polyethylene glycol-amine and 0.07 part of boron trifluoride were added, and stirred at 45 °C for 2.5 h, filtered, washed, and dried to obtain polyethylene glycol-modified nano-aluminum oxide; (3) 16 parts of polyethylene glycol-modified nano-aluminum oxide were added to 35 parts of deionized water and ultrasonically dispersed evenly, 0.75 part of tetrafluoropropionic acid and 1.5 parts of activator were added, and stirred at 55 °C for 5 h to obtain modified nano-aluminum oxide.

[0071] Performance Test: (1) The contact angles of Examples 1 to 5 and Comparative Examples 1 to 2 were measured using an optical contact angle measuring instrument, and the experimental data are shown in Table 1; (2) Whether there were bubble phenomena after the samples of each example and comparative example were prepared into lithium metal anodes was observed, and a universal testing machine was used to measure the peel force at a speed of 100 mm / min, and the experimental data are shown in Table 1 and Table 2; (3) After Examples 1, 4, 5 and Comparative Examples 1, 3, 4 were prepared into lithium metal anodes, they were assembled into batteries, and at a current density of 1 mA / cm 2 The batteries were cycled 100 times, and according to GB / T 43695-2024, the Coulombic cycle efficiency of the batteries was measured and calculated, and the experimental data are shown in Table 2.

[0072] Table 1

[0073] Item Contact Angle / ° <![CDATA[Peeling force / N·m -1 > Presence or Absence of Bubbles Example 1 45.589 613 None Example 2 53.621 273 None Example 3 47.807 398 None Example 4 55.648 356 Yes Example 5 46.722 681 None Comparative Example 1 58.389 473 Yes Comparative Example 2 43.821 481 Yes

[0074] Table 2

[0075]

[0076]

[0077] Conclusion: From Figures 1 to 4 Table 1 and Table 2, it can be seen that at a 22% laser power, i.e., the laser etching effect of Example 1 is the best: at a 27% laser power, although the contact angle of Comparative Example 2 is lower, due to the too large and dense nano-pores, gas residues are likely to occur, resulting in a decrease in bubbles and peel force; while for Examples 2 and 3, due to the relatively low laser power, the laser etching effect is average, and the contact angle and peel force are poor; the laser etching shape of Example 4 is circular, the peel force is poor, and bubbles are generated; therefore, Example 1 is used as the basis for subsequent experiments.

[0078] As can be seen from Table 1, in Comparative Example 1, a carbon-coated slurry was coated on the surface of the copper current collector by a traditional method. The lithium metal anode obtained reacted with lithium due to the moisture in the slurry, resulting in obvious bubbles; in Comparative Example 3, without introducing modified alumina, the ability to inhibit the growth of lithium dendrites decreased, and the Coulombic cycle efficiency decreased; in Comparative Example 4, a layer of modified nano-alumina was directly attached to the surface of the copper foil, the interfacial compatibility decreased, the peel force decreased, and due to being directly attached to the surface of the copper foil, the surface uniformity was relatively average, resulting in a concentrated local current density and accelerating the growth of lithium dendrites, and the Coulombic cycle efficiency decreased.

[0079] In summary, in the present invention, ultraviolet picosecond is used for laser etching on the surface of the current collector. Compared with the original current collector, the contact angle is reduced and the peel force with the lithium strip is increased. At the same time, the present invention pre-treats the surface of the current collector after laser etching, and has good Coulomb cycle efficiency while ensuring the peel force, and successfully provides a laser-etched current collector with excellent performance for the lithium metal negative electrode of a solid-state battery, which can achieve the technical effect of having a carbon-coated layer on the current collector while solving the problem of wrinkles of the existing current collector during winding in the preparation process and improving the production yield.

[0080] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or perform equivalent replacements for some of the technical features. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A laser-etched current collector applied to the lithium metal anode of a solid-state battery, characterized in that: The surface of the current collector is provided with concave holes; the diameter of the concave holes is 10-50 nm, the depth is 30-80 nm, and the distance between the concave holes is 10-50 nm.

2. The laser-etched current collector applied to the lithium metal anode of a solid-state battery according to claim 1, wherein: The shape of the concave holes includes one with a narrower end and a wider end, strip-shaped, circular, or polygonal; preferably, it is in the shape of a water droplet.

3. A laser-etched current collector applied to a lithium metal anode of a solid-state battery according to claim 1, characterized in that: The concave holes are obtained by ultraviolet picosecond laser etching of the metal copper layer on the surface of the current collector; during the laser etching process, the etching laser power is 18-22%, the laser frequency is 800 kHz, the engraving speed is 4000 mm / s, and the laser width is 0.008-0.010 mm.

4. A laser-etched current collector for a lithium metal anode of a solid-state battery according to claim 1, characterized in that: The middle of the current collector is a polymer film layer, and both sides are metal copper layers; the polymer film layer includes one of a PET layer or a PP layer; the thickness of the polymer film layer is 4.5 ± 0.5 μm, and the thickness of the metal copper layer is 1 ± 0.1 μm.

5. The laser-etched current collector for a lithium metal anode applied to a solid-state battery according to claim 1, wherein: The current collector according to any one of claims 1-4 is used for preparing a lithium metal negative electrode. The process is as follows: in a dehumidified environment, a lithium strip and the laser-etched current collector are roll-pressed in a rubber roll press to form a lithium metal negative electrode with the laser-etched current collector as the middle interlayer.

6. The laser-etched current collector applied to the lithium metal anode of a solid-state battery according to claim 5, wherein: During the roll-pressing process, the dew point temperature is -50 to -70 °C, the roll-pressing pressure is 8-12 T, and the speed is 18-20 m / min.

7. The laser-etched current collector for a lithium metal anode applied to a solid-state battery according to claim 1, wherein: The preparation method of the laser-etched current collector includes the following steps: S1: The metal copper layer of the current collector is etched by ultraviolet picosecond laser to obtain a laser-etched functional current collector. S2: The laser-etched functional current collector is immersed in a dopamine solution, stirred at 40-45 °C for 3-4 h, taken out, rinsed with absolute ethanol, and dried in a nitrogen atmosphere to obtain a functional current collector A. S3: Modified nano-aluminum oxide is added to acetonitrile and dispersed evenly, the pH is adjusted to 8-9 to obtain a slurry. The slurry is sprayed on the surface of the functional current collector A with a thickness of 10-20 μm and dried at 70-80 °C under vacuum conditions to obtain a functional current collector B. S4: The functional current collector B is re-immersed in the dopamine solution, stirred at 40-45 °C for 6-8 h, taken out, rinsed with absolute ethanol, and dried in a nitrogen atmosphere to obtain the laser-etched current collector.

8. A laser-etched current collector applied to the lithium metal anode of a solid-state battery according to claim 7, characterized in that: The dopamine solution includes the following raw materials: 1.2-1.5 g / L hydrochloric acid dopamine, 15-17 g / L piperidine, and the solvent is absolute ethanol; the mass ratio of the modified nano-aluminum oxide to acetonitrile is 1:0.5-1.

9. A laser-etched current collector applied to the lithium metal anode of a solid-state battery according to claim 7, characterized in that: The preparation method of the modified alumina includes the following steps: (1) Nano-aluminum oxide is added to an ethanol solution and ultrasonically dispersed evenly, 3-(2,3-epoxypropoxy)propyltrimethoxysilane is added, and stirred at 40-50 °C for 1-2 h, filtered, washed, and dried to obtain epoxidized nano-aluminum oxide. (2) The epoxidized nano-aluminum oxide is ultrasonically dispersed in anhydrous tetrahydrofuran, tetra-arm polyethylene glycol-amine and boron trifluoride are added, and stirred at 40-50 °C for 2-3 h, filtered, washed, and dried to obtain polyethylene glycol-modified nano-aluminum oxide. (3) The polyethylene glycol-modified nano-aluminum oxide is added to deionized water and ultrasonically dispersed evenly, tetrafluoropropionic acid and an activator are added, and stirred at 50-60 °C for 4-6 h to obtain modified nano-aluminum oxide.

10. A lithium metal anode, characterized in that Comprising the current collector according to any one of claims 1 to 9 and a lithium strip on the surface of the current collector.

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