Preparation method and application of laser-induced fluorine-doped graphene array

Abstract

The application belongs to the technical field of graphene electrode materials, and particularly relates to a preparation method of laser-induced fluorine-doped graphene array and application thereof. The application firstly pastes a layer of polyimide (PI) film on a copper foil, then pastes a layer of polytetrafluoroethylene (PTFE) film on the PI surface, and then performs laser treatment on the double-layer polymer polymer film twice to form a fluorine-doped graphene (F-LIG) array through laser induction, and finally obtains a fluorine-doped graphene array composed of the copper foil, the PI column and the F-LIG. The method for preparing the fluorine-doped graphene is simple, and can generate the fluorine-doped graphene array (F-LIG array) in one step under normal temperature, normal pressure and ambient atmosphere. Meanwhile, the prepared F-LIG array can be used as a host material of a lithium metal battery negative electrode, so that the prepared lithium metal battery has the advantages of low nucleation overpotential, good cycle stability, excellent rate performance and the like.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of graphene electrode materials, and particularly relates to a preparation method of laser-induced fluorine-doped graphene array and application thereof. BACKGROUND

[0002] With the continuous development of human society, the current lithium ion battery using graphite negative electrode (372 mAh·g -1 ) has reached its theoretical limit in terms of energy density, and cannot meet the growing demand for energy storage systems, so it is urgent to develop secondary batteries with higher energy density. Among them, lithium metal stands out among many negative electrode materials because it has a very high theoretical specific capacity (3860 mAh·g -1 ), a very low reduction potential (-3.04 V·vs. standard hydrogen electrode) and an ultra-low density (0.534 g·cm -3 ), and thus becomes the most ideal negative electrode material. In recent years, in order to realize the commercialization of lithium metal negative electrode, researchers have done a lot of work, but they have always failed to completely solve its three major challenges, mainly manifested as: (1) lithium metal has high chemical reactivity, and once it comes into contact with liquid electrolyte, it will undergo an irreversible chemical reaction and form a layer of uneven solid electrolyte interface (SEI) film on the surface of lithium metal. Since this SEI film cannot withstand the huge volume change of lithium metal during battery cycling, the SEI film repeatedly breaks and generates, eventually leading to a decrease in coulombic efficiency and a decrease in battery capacity. (2) Since lithium metal is in a host-free state, it will produce infinite volume expansion during deposition / detachment, which may cause the electrode to powder. (3) Lithium metal is prone to uncontrollable lithium dendrite growth, which may cause battery short circuit and even cause battery explosion. Therefore, it is of great scientific significance and practical application value to solve the problem of lithium dendrite growth and obtain lithium metal batteries with stable cycle performance and high safety performance.

[0003] In recent years, porous carbon materials (such as carbon nanotubes, carbon nanofibers, carbon nanospheres, graphene, etc.) with large specific surface area and rich pore structure are widely used in the modification of negative electrodes of lithium metal batteries. By matching these host materials with lithiumophilic sites, the growth of lithium dendrites can be inhibited to some extent, and the volume expansion of lithium metal can be relieved. However, the SEI film formed by these materials is still uneven and fragile. The uneven SEI may break and recombine during the long-term cycling of the battery, leading to capacity decay. Therefore, a beneficial substance can be found to be uniformly distributed in the SEI to improve the stability of the SEI. Among various candidates for beneficial substances, LiF is considered to be the most promising compound in the SEI to change the growth pattern of lithium metal, because the interfacial energy of LiF with lithium metal is the highest. In the method of forming a LiF-rich SEI on the surface of a three-dimensional porous electrode, in-situ lithiation of fluorine-doped carbon materials is a relatively convenient method. Among them, graphene is an excellent host material, and fluorine-doped graphene prepared therefrom has been widely used. Currently, the preparation of traditional fluorine-doped graphene generally uses F2 and XeF2 as fluorinating agents for gas-phase fluorination of graphene. However, due to the high price, difficult operation and certain safety hazards of fluorinating agents, the popularization and application of fluorine-doped graphene are restricted to some extent. Therefore, it is necessary to develop a simple and efficient method for preparing three-dimensional porous fluorine-doped graphene and simultaneously apply it to lithium metal negative electrodes. SUMMARY

[0004] In order to overcome the shortcomings of the prior art, the present application generates fluorine-doped graphene (F-LIG) by laser induction twice, and combines the material with copper foil and PI column to form an F-LIG array. The obtained F-LIG array can be used as a host material for the negative electrode of a lithium metal battery, so that the lithium metal battery prepared has low nucleation overpotential, good cycle stability, excellent rate performance and other advantages.

[0005] In order to achieve the above purpose, the technical scheme adopted by the present application is:

[0006] The first aspect of the present application provides a preparation method of laser-induced fluorine-doped graphene array, which comprises the following steps:

[0007] S1, a copper foil (Cu) current collector is covered on a substrate, then a polyimide (PI) film is attached to the copper foil, and a polytetrafluoroethylene (PTFE) film is attached to the PI to form a PTFE-PI composite film;

[0008] S2, the PTFE-PI composite film is processed by row-by-row and column-by-column laser scribing with a depth of 100%, so that the scribed part of the PTFE-PI composite film is converted into laser-induced fluorine-doped graphene F-LIG, and the remaining unprocessed PTFE-PI composite film is divided into multiple PTFE-PI columns by the scribing, thereby forming a pretreated laser-induced fluorine-doped graphene array p-F-LIG-a;

[0009] S3, all areas on the surface of the p-F-LIG-a are processed by equal-interval row-by-row laser scribing with a depth of 50-70%, and the upper part of the PTFE-PI column is converted into F-LIG by using laser energy, thereby obtaining a laser-induced fluorine-doped graphene array F-LIG-a composed of a copper foil, a PI column and F-LIG.

[0010] The present application first pastes a layer of polyimide (PI) film on a copper foil, then pastes a layer of polytetrafluoroethylene (PTFE) film on the surface of the PI, and then performs two laser treatments on the double-layer high polymer film to form a fluorine-doped graphene (F-LIG) array by laser induction, and finally obtains a fluorine-doped graphene array composed of a copper foil, a PI column and F-LIG. The method for preparing fluorine-doped graphene of the present application is simple, can generate a fluorine-doped graphene array (F-LIG array) in one step at normal temperature and pressure and in an environment atmosphere, and is conducive to large-scale production and application.

[0011] Preferably, the thickness of the copper foil current collector is 0.005-0.015 mm, the thickness of the polyimide PI film is 0.05-0.09 mm, and the thickness of the polytetrafluoroethylene PTFE film is 0.04-0.07 mm.

[0012] Preferably, in steps S2 and S3, the laser scribing uses a CO2 laser with a wavelength of 10.6 μm.

[0013] Preferably, in step S2, the process parameters of the laser scribing are as follows: the spot size is 0.1-0.3 mm, the scanning speed is 40-60 mm / s -1 , the width of each line is 0.1-0.3 mm, and the row spacing and column spacing of the scribing are equal, and the interval distance is 0.1-0.5 mm.

[0014] Preferably, in step S3, the process parameters of the laser scribing are as follows: the spot size is 0.1-0.3 mm, the scanning speed is 90-110 mm / s, and the scanning interval is 0.01-0.05 mm.

[0015] Preferably, in step S3, the processing depth of the laser scribing is 59% of the PTFE-PI composite film.

[0016] The second aspect of the present invention provides a fluorine-doped graphene array obtained by the preparation method described in the first aspect.

[0017] The fluorine-doped graphene (F-LIG) array prepared by the method of the present invention can be used as the host material for the negative electrode of a lithium metal battery, so that the prepared lithium metal battery has the advantages of low nucleation overpotential, good cycle stability, and excellent rate performance.

[0018] The third aspect of the present invention provides the use of the fluorine-doped graphene array described in the second aspect in the preparation of a lithium metal battery.

[0019] Preferably, the fluorine-doped graphene (F-LIG) array is used to prepare the negative electrode of a lithium metal battery, such as Li||F-LIG-a half-cell, Li@F-LIG-a||Li@F-LIG-a symmetric cell, Li@F-LIG-a||LFP full cell, etc.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] The present invention discloses a method for preparing a laser-induced fluorine-doped graphene array. First, a layer of polyimide (PI) film is attached to a copper foil, and then a layer of polytetrafluoroethylene (PTFE) film is attached to the PI surface. Then, the double-layer polymer film is laser-treated twice, and a fluorine-doped graphene (F-LIG) array is formed by laser induction, and finally a fluorine-doped graphene array consisting of copper foil, PI columns and F-LIG is obtained. The present invention irradiates the PTFE-PI double-layer film with a laser twice, utilizes the different absorptivity of the two polymer films to a specific wavelength laser, and then selectively excites the lower layer PI to be converted into graphene, and utilizes the photothermal effect and photochemical effect at the interface of the double-layer film to trigger the decomposition of the upper layer PTFE and participate in the formation process of the graphene below. Finally, the laser-induced fluorine-doped graphene array is obtained, and efficient preparation of fluorine-doped graphene is achieved. At the same time, the in-situ lithiation in the electrochemical reaction process is utilized to generate a LiF-rich SEI film, thereby improving the stability of the lithium metal negative electrode SEI film.

[0022] The application combines fluorine-doped graphene array with copper foil and PI column to form F-LIG array, the hierarchical structure of the F-LIG array is novel, and the overall stability is good, the F-LIG array can be used as a host material of a lithium metal battery negative electrode, a good current path is formed between the F-LIG and the copper foil, the flexible PI column not only plays the role of an adhesive, but also can effectively buffer the huge volume expansion of the metal lithium in the charging and discharging process. The C-F semi-ionic bond in the F-LIG can also adsorb lithium ions, which not only reduces the nucleation overpotential of the metal lithium, but also improves the deposition behavior of the lithium ions, which is beneficial to induce uniform deposition and dendrite-free growth of the metal lithium. In addition, the F-LIG can react with lithium ions in situ to generate a SEI film rich in LiF, thereby further improving the electrochemical performance of the lithium metal battery. Therefore, the lithium metal battery prepared by using the F-LIG array of the application has the advantages of low nucleation overpotential, good cycle stability, excellent rate performance and the like. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 It is a vertical sectional structure schematic diagram of p-F-LIG-a precursor;

[0024] Figure 2 It is a scanning electron microscope diagram of p-F-LIG-a precursor;

[0025] Figure 3 It is a vertical sectional structure schematic diagram of F-LIG array;

[0026] Figure 4 It is a vertical sectional structure schematic diagram of LIG array;

[0027] Figure 5 It is an optical picture of LIG array;

[0028] Figure 6 It is a scanning electron microscope diagram of LIG array;

[0029] Figure 7 It is an optical picture of F-LIG array;

[0030] Figure 8 It is a scanning electron microscope diagram of F-LIG array;

[0031] Figure 9 It is a nucleation overpotential diagram of a lithium metal battery with LIG and F-LIG array as negative electrode material;

[0032] Figure 10 It is a rate performance diagram of a lithium metal battery with LIG and F-LIG array as negative electrode material;

[0033] Figure 11 It is a cycle performance diagram of a lithium metal battery with LIG and F-LIG array as negative electrode material. DETAILED DESCRIPTION

[0034] The specific embodiments of the present application will be further described below. It should be noted that the description of these embodiments is intended for the purpose of aiding in the understanding of the present application and is not intended to be limiting of the present application. Moreover, the technical features involved in each of the embodiments of the present application described below can be combined with each other as long as there is no conflict.

[0035] The experimental methods in the following examples are all conventional methods unless otherwise specified. The experimental materials used in the following examples are all commercially available unless otherwise specified.

[0036] Example: Preparation of laser-induced fluorine-doped graphene array

[0037] The commercial CO2 laser engraving machine used in this embodiment is a 3020 type laser engraving machine with a wavelength of 10.6 μm, which is purchased from Shanghai Fengtuo Trading Co., Ltd. The preparation of the fluorine-doped graphene array specifically includes the following steps:

[0038] (1) A copper foil current collector with a thickness of 0.009 mm and an area of 7 cm x 7 cm is evenly covered on a size of 15 cm x 15 cm x 0.2 cm acrylic plate, then a commercial polyimide (PI) tape with a thickness of 0.06 mm and an area of 10 cm x 10 cm is pasted on the copper foil and washed with absolute ethanol, followed by pasting a commercial polytetrafluoroethylene (PTFE) tape with a thickness of 0.05 mm and an area of 8 cm x 8 cm on the PI and washing with absolute ethanol, finally forming a PTFE-PI double-layer film;

[0039] (2) In an air atmosphere, a commercial CO2 laser engraving machine with a wavelength of 10.6 μm is used to perform the first laser processing on the PTFE-PI double-layer film in step (1), the processing area is a square of 41.8 mm x 41.8 mm, and the laser parameters used are: spot size is 0.2 mm, scanning speed is 50 mm·s -1 , processing depth is 0.11 mm (processing depth is 100% of the PTFE-PI composite film); the PTFE-PI double-layer film is processed by drawing lines in the processing area, the PTFE-PI double-layer film in the drawn line part is induced to F-LIG, the width of each line is 0.2 mm, and the interval distance is 0.2 mm, after laser processing, the drawn line part forms a laser-induced fluorine-doped graphene (F-LIG) array of 105 rows x 105 columns, and the remaining unprocessed PTFE-PI film in the processing area is divided into multiple 0.2 mm x 0.2 mm PTFE-PI columns by the drawn lines, thereby obtaining a preprocessed fluorine-doped graphene array (p-F-LIG-a) precursor.

[0040] Figure 1 A vertical cross-sectional structure diagram of p-F-LIG-a, Figure 2 A scanning electron microscope diagram of p-F-LIG-a, it can be observed that the surface of p-F-LIG-a has more PTFE particles and poor morphology, and is also not suitable as an electrode material.

[0041] (3) The precursor in step (2) was subjected to equal-interval line-by-line laser scanning using a commercial CO2 laser engraving machine with a wavelength of 10.6 μm, and the processing area covered the entire surface of the precursor. The laser parameters used were: spot size 0.2 mm, scanning speed 100 mm / s, scanning interval of each line 0.02 mm, and processing depth 0.065 mm (processing depth was 59% of the PTFE-PI composite film). After laser processing, the laser-processed part (0.075 mm) of the PTFE-PI column was induced into F-LIG. The vertical cross-sectional structure after laser processing is shown in Figure 3 , which shows the F-LIG of the scribed part (line width 0.2 mm) and the PI column (thickness 0.045 mm, lower part) and F-LIG (thickness 0.075 mm, upper part) divided by the scribe, thereby obtaining a laser-induced fluorine-doped graphene array composed of copper foil, PI column and F-LIG, i.e. F-LIG array.

[0042] Preparation of laser-induced graphene array

[0043] (1) In order to perform performance comparison, a copper foil current collector with a thickness of 0.009 mm and an area of 7 cm x 7 cm was evenly covered on a size of 15 cm x 15 cm acrylic plate, and a commercial polyimide (PI) tape with a thickness of 0.06 mm and an area of 10 cm x 10 cm was pasted on the copper foil and washed with anhydrous ethanol.

[0044] (2) The surface was subjected to first laser processing under air atmosphere using a commercial CO2 laser engraving machine with a wavelength of 10.6 μm, and the processing area was a square of 41.8 mm x 41.8 mm. The laser parameters used were: spot size 0.2 mm, scanning speed 50 mm / s, and processing depth 0.06 mm (processing depth was 100% of the PI film). The PI film was scribed line by line within the processing area, so that the scribed part of the PI film was induced into LIG. The width of each line was 0.2 mm, and the interval distance was 0.2 mm. After laser processing, the scribed part formed a laser-induced graphene (LIG) array of 105 rows x 105 columns, and the remaining unprocessed PI film in the processing area was divided into multiple 0.2 mm x 0.2 mm PI columns by scribing, forming a p-LIG-a precursor. -1 ​

[0045] (3) The precursor in step (2) was subjected to equal-interval line-by-line laser scanning with a commercial CO2 laser engraving machine with a wavelength of 10.6 μm, and the processing area covered the entire surface of the precursor. The laser parameters used were: spot size 0.2 mm, scanning speed 100 mm / s, scanning interval of each line 0.05 mm, and processing depth 0.015 mm (processing depth was 25% of the PI film). After laser processing, the laser-processed part (0.075 mm) of the PI column was induced into LIG. The vertical cross-sectional structure after laser processing is shown in FIG. 1B, which shows the LIG in the scribed part (line width 0.2 mm) and the PI column (thickness 0.045 mm, lower part) and LIG (thickness 0.075 mm, upper part) divided by the scribed line with a width of 0.2 mm, thereby obtaining a laser-induced graphene array composed of copper foil, PI column and LIG, i.e. LIG array. Figure 4

[0046] The LIG array of the comparative example and the F-LIG array of the example were characterized in terms of morphology. Among them, Figure 5 and Figure 6 are the optical and scanning electron microscope images of the LIG array, respectively, and it can be observed that it presents a clear 105 row x 105 column array structure, in which the horizontal and vertical line parts are LIG, and the multiple 0.2 mm x 0.2 mm square-shaped areas divided by the horizontal and vertical lines are PI columns and LIG on the PI columns. Figure 7 and Figure 8 are the optical and scanning electron microscope images of the F-LIG array, respectively, and it can be observed that it presents a clear 105 row x 105 column array structure, in which the horizontal and vertical line parts are F-LIG, and the multiple 0.2 mm x 0.2 mm square-shaped areas divided by the horizontal and vertical lines are PI columns and F-LIG on the PI columns.

[0047] Experimental Example: Application and Performance Characterization of F-LIG Array as Anode Material in Lithium Metal Battery

[0048] The F-LIG array in the example and the LIG array in the comparative example were cut into circular electrode pieces with a diameter of 12 mm, and were used as lithium metal battery anode host materials for electrochemical performance testing.

[0049] 1. Characterization of nucleation overpotential

[0050] ​(1) Assembly of half-cells: LIG and F-LIG array round electrodes with a diameter of 12 mm were paired with lithium metal foil of the same size to assemble Li||LIG-a and Li||F-LIG-a half-cells in an argon-filled glovebox with water and oxygen contents both below 0.01 ppm. The electrolyte system was selected as 1,3-dioxolane (DOL) / dimethoxyethane (DME) (v / v = 1:1) solution containing 2 wt% lithium nitrate (LiNO3) electrolyte additive and 1 mol / L lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), the amount of electrolyte was 60 μL, and the separator was a commercial polypropylene porous membrane.

[0051] (2) Electrochemical tests: Li||LIG-a and Li||F-LIG-a half-cells were first cycled between 0.01-3 V at a current of 0.05 mA·cm -2 for 5 times, and then 1 mAh·cm -2 of metal lithium was repeatedly deposited / stripped at a current of 1 mA·cm -2 , and the nucleation overpotential was shown in Figure 9 , which was the difference between the lowest voltage and the stable voltage during lithium deposition. The nucleation overpotential of Li||F-LIG half-cell was only 7.9 mV, which was less than that of Li||LIG-a half-cell (12.9 mV), indicating that the C-F semi-ionic bond in F-LIG had an adsorption effect on lithium ions, which could effectively reduce the nucleation overpotential of metal lithium.

[0052] 2. Characterization of rate performance

[0053] (1) Assembly of symmetric cells: Li||LIG-a and Li||F-LIG-a half-cells were first assembled, and then cycled between 0.01-3 V at a current of 0.05 mA·cm -2 for 5 times, after which Li||LIG-a and Li||F-LIG-a half-cells were electrodeposited at a discharge current of 0.5 mA·cm -2 , and 10 mAh·cm -2 of metal lithium was pre-deposited; then the half-cells were disassembled in the glovebox, and the composite metal lithium anodes Li@LIG-a and Li@F-LIG-a were taken out, washed with excess DME to remove the residual electrolyte on the surface and dried, and then two pieces of composite lithium anodes Li@LIG-a and Li@F-LIG-a with the same metal lithium capacity were taken to assemble Li@LIG-a||Li@LIG-a and Li@F-LIG-a||Li@F-LIG-a symmetric cells, respectively, and the electrolyte system was the same as that of the half-cell.

[0054] (2) Electrochemical test: Li@LIG-a||Li@LIG-a and Li@F-LIG-a||Li@F-LIG-a symmetric cells were repeatedly deposited / stripped 1 mAh·cm -2 -2 of lithium metal at a current of 1-20 mA·cm -2 -2, as shown in Figure 10 , it can be seen that Li@F-LIG-a||Li@F-LIG-a symmetric cells exhibit smaller overpotential than Li@LIG-a||Li@LIG-a symmetric cells at each current density.

[0055] 3. Characterization of cycle performance

[0056] (1) Assembly of full cells: Li||LIG-a and Li||F-LIG-a half-cells were first assembled, then cycled 5 times between 0.01-3 V at a current of 0.05 mA·cm -2 -2, after which the Li||LIG-a and Li||F-LIG-a half-cells were electrodeposited with a discharge current of 0.5 mA·cm -2 -2, and 5 mAh·cm -2 of lithium metal was pre-deposited; then the half-cells were disassembled in a glove box, and the composite lithium metal anodes Li@LIG-a and Li@F-LIG-a were removed; lithium iron phosphate (LFP) cathode sheets with an active material loading of 20 mg·cm -2 -2 were placed in the glove box with the composite lithium metal anodes to assemble Li@LIG-a||LFP and Li@F-LIG-a||LFP full cells, respectively. The electrolyte system used was a 1 mol / L lithium hexafluorophosphate (LiPF6) ethylene carbonate (EC) / diethyl carbonate (DEC) (v / v = 1:1) solution, and the amount of electrolyte used was 40 μL, with a polypropylene porous membrane as the separator material.

[0057] (2) Electrochemical test: Li@LIG-a||LFP and Li@F-LIG-a||LFP full cells were charged and discharged between 2.4-4.0 V at a 0.5C rate, and the long cycle performance was obtained as shown in Figure 11 , it can be seen that the initial discharge specific capacity of Li@F-LIG||LFP full cells is 139.48 mAh·g -1 , and the discharge specific capacities after 10, 20, 30, 40, and 50 cycles are 134.75, 131.48, 128.38, 125.53, and 122.75 mAh·g -1 , respectively, and finally a high discharge specific capacity of 120.90 mAh·g -1The capacity retention rate is 86.6%, which indicates that the SEI film rich in LiF can greatly improve the electrochemical performance of the lithium metal full battery, and the full battery still has excellent cycle performance under harsh conditions.

[0058] As can be seen from the above, the present application uses a 10.6 μm wavelength CO2 laser to generate fluorine-doped graphene (F-LIG) by laser induction on a PTFE and PI double-layer film, and combines the material with a copper foil and a PI column to form an F-LIG array, the prepared F-LIG array can be used as a host material of a lithium metal battery negative electrode, compared with an LIG array without F-doping, the lithium metal battery prepared by using the F-LIG array as an electrode has the advantages of low nucleation overpotential, good cycle stability, excellent rate performance and the like. Moreover, the method for preparing fluorine-doped graphene is simple, can be completed in one step at normal temperature and pressure and in an environment atmosphere, and is conducive to large-scale popularization and application.

[0059] The embodiments of the present application are described in detail above, but the present application is not limited to the described embodiments. For those skilled in the art, various changes, modifications, replacements and variations of the embodiments can be made without departing from the principles and spirits of the present application, and still fall within the protection scope of the present application.

Claims

1. A method for preparing a laser-induced fluorine-doped graphene array, characterized in that: The following steps are involved: S1. Cover the copper foil current collector on the substrate, then stick a polyimide PI film on the copper foil, and then stick a polytetrafluoroethylene PTFE film on the PI to form a PTFE-PI composite film; S2. Laser scribing the PTFE-PI composite membrane row by row and column by column to a processing depth of 100%, converting the PTFE-PI composite membrane in the marked portion into laser-induced fluorine-doped graphene F-LIG. The remaining unprocessed PTFE-PI composite membrane is divided into multiple PTFE-PI columns by the scribing, thereby forming a pretreated laser-induced fluorine-doped graphene array pF-LIG-a. S3. Laser scribing is performed on all areas of the pF-LIG-a surface with a processing depth of 50-70% at equal intervals. The upper part of the PTFE-PI pillars is converted into F-LIG using laser energy, resulting in a laser-induced fluorine-doped graphene array F-LIG-a composed of copper foil, PI pillars, and F-LIG.

2. The method for preparing a laser-induced fluorine-doped graphene array according to claim 1, wherein: The thickness of the copper foil current collector is 0.005-0.015 mm, the thickness of the polyimide PI film is 0.05-0.09 mm, and the thickness of the polytetrafluoroethylene PTFE film is 0.04-0.07 mm.

3. The method for preparing a laser-induced fluorine-doped graphene array according to claim 1, wherein: In steps S2 and S3, the laser scribing is CO2 laser engraving.

4. The method for preparing a laser-induced fluorine-doped graphene array according to claim 1, wherein: In step S2, the process parameters of the laser scribing are: scanning speed of 40-60 mm·s -1 The width of each line is 0.1-0.3 mm, the row spacing and column spacing of the lines are equal, and the spacing distance is 0.1-0.5 mm.

5. The method for preparing a laser-induced fluorine-doped graphene array according to claim 1, wherein: In step S3, the process parameters of the laser scribing are: a scanning speed of 90-110 mm / s, and a scanning interval of 0.01-0.05 mm.

6. The method for preparing a laser-induced fluorine-doped graphene array according to claim 1, wherein: In step S3, the processing depth of the laser scribing is 59% of the PTFE-PI composite film.

7. A fluorine-doped graphene array obtained by the preparation method according to any one of claims 1 to 6.

8. Use of the fluorine-doped graphene array according to claim 7 in the preparation of lithium metal batteries.

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