Polymer / metal-based oxyhalide composite modified current collector and lithium metal battery

Abstract

The invention discloses a current collector compositely modified by a polymer / metal-based oxyhalide and application of the current collector in a lithium metal battery, and the current collector is prepared by using the polymer and the metal-based oxyhalide as raw materials to prepare slurry and coating the surface of the current collector of the lithium metal battery with the slurry. A solid electrolyte interface (SEI) layer rich in lithium oxyhalide (Li3OX, X = Cl, Br, I) fast ion conductors is generated in situ through metal-based oxyhalide and lithium metal. The composite interface protection layer formed by the polymer organic component and the metal-based oxyhalide inorganic component has excellent flexibility, can adapt to the volume change of lithium metal in the charging and discharging process, guarantees the integrity and mechanical properties of an SEI layer, and inhibits the growth of lithium dendrites; in addition, in-situ formation of a lithium oxyhalide-rich fast lithium ion conductor can promote fast diffusion and transfer of lithium ions, and the long-term cycle performance of the lithium metal battery under high rate is improved.

Description

Technical Field

[0001] The present invention belongs to the field of lithium metal battery current collector materials and electrochemistry, and specifically relates to a current collector compositely modified with a polymer and a metal-based oxyhalide, and a preparation method and application thereof. Background Art

[0002] Lithium metal batteries, as a high-performance secondary battery technology, have attracted widespread attention in recent years. Compared with traditional lithium-ion batteries, lithium metal batteries can provide higher energy output, which is of great significance for fields such as electric vehicles (EVs) and portable electronic devices. However, the development of lithium metal batteries also faces many challenges. For example, the in-situ formed SEI layer is uneven and easily broken after multiple charge and discharge cycles, resulting in the exposure of fresh lithium, exacerbating the side reactions between lithium and electrolyte, increasing the loss of active lithium, leading to decreased battery performance and shortening the battery cycle life. In addition, lithium dendrites are easily formed during the cycling process. These lithium dendrites may penetrate the battery separator, causing battery short circuits and posing safety issues. To address these issues, researchers have explored various strategies. For example, the Piao research team proposed an inorganic hybrid layer-enriched carbon framework (IHL@CF) as a three-dimensional lithiophilic host to stabilize and optimize the SEI layer. The outer layer of IHL@CF is an inorganic hybrid layer (IHL) composed of silver-lithium alloy and Li2S / LiF, which promotes uniform lithium deposition, inhibits dendrite growth, and enhances SEI stability. The inner hard carbon layer facilitates the effective adsorption and intercalation of lithium ions while maintaining the mechanical integrity and porosity of the three-dimensional framework. The results of the above research provide some new ideas for the rational design of SEI layer and uniform lithium deposition. However, the modified current collector prepared by a two-step hydrothermal, deposition, and pre-lithiation process is cumbersome and difficult to achieve large-scale production. Moreover, the SEI layer prepared on the modified current collector by this method lacks flexibility and cannot better adapt to the volume expansion problem of lithium metal batteries after multiple charge and discharge cycles, which easily leads to SEI rupture (Small, 2025, 21, 2411527). In addition, Chen's research team explored a new type of bismuth copper oxide foam current collector (BO@CF) by in situ forming a dual-functional interface mediation layer composed of a lithium-electrolyte interface (SEI). This design enhances lithium ion transport, reduces nucleation overpotential, and improves the uniformity of lithium deposition. However, the annealing treatment undoubtedly increases the preparation cost, and the production process has many side reactions, the intermediate products have no utilization value, and it is difficult to control the generation of the target product, which to a certain extent causes problems such as resource waste and operational difficulties (J.Mater.Chem.A, 2025, 13, 13048-13057). Summary of the Invention

[0003] The present invention addresses the current problems of uneven SEI formation between lithium metal and the electrolyte during cycling, which is prone to breakage after multiple charge and discharge cycles, exposing active lithium and exacerbating side reactions, leading to poor cycling performance, low Coulombic efficiency, and poor safety. A method for preparing and applying a current collector modified with a polymer and metal-based oxyhalide composite is proposed. Through simple dispersion and drying processes, a slurry of the mixed polymer and metal-based oxyhalide is uniformly and firmly attached to the surface of the lithium metal battery current collector. The metal-based oxyhalide and lithium metal in situ form a solid electrolyte interface (SEI) layer rich in lithium oxyhalide (Li3OX, X=Cl, Br, I) fast ion conductors. This composite interface protective layer, composed of the polymer organic component and the metal-based oxyhalide inorganic component, exhibits excellent flexibility, adapts to the volume changes of lithium metal during charge and discharge, maintains the integrity and mechanical properties of the SEI layer, and inhibits the growth of lithium dendrites. Furthermore, the in situ formation of the lithium oxyhalide-rich fast lithium ion conductor promotes rapid diffusion and transfer of lithium ions, improving the long-term cycling performance of lithium metal batteries at high rates.

[0004] In order to achieve the above technical objectives, the present invention adopts the following technical solutions:

[0005] A current collector and a lithium metal battery compositely modified with a polymer and a metal-based oxyhalide are prepared by using the polymer and the metal-based oxyhalide as raw materials to prepare a slurry, which is then attached to the surface of the lithium metal battery current collector.

[0006] Furthermore, the polymer is one or more of polyvinylidene fluoride-hexafluoropropylene copolymer, polymethyl methacrylate, polyvinylidene fluoride, polyacrylic acid, polytetrafluoroethylene, polyaniline, polypyrrole, polythiophene and derivatives thereof.

[0007] Furthermore, the metal-based oxyhalide is one or more of bismuth oxychloride (BiOCl), indium oxychloride (InOCl), vanadium oxychloride (VOCl2, VOCl3), tantalum oxychloride (TaOCl3), niobium oxychloride (NbOCl3), molybdenum oxychloride (MoOCl4, MoO2Cl2), tungsten oxychloride (WOCl4, WO2Cl2), lanthanum oxychloride (LaOCl), bismuth oxybromide (BiOBr), indium oxybromide (InOBr), vanadium oxybromide (VOBr3), niobium oxybromide (NbOBr3), tungsten oxybromide (WOBr4), lanthanum oxybromide (LaOBr), bismuth oxyiodide (BiOI), and lanthanum oxyiodide (LaOI).

[0008] Furthermore, the lithium metal battery current collector is copper foil, aluminum foil or carbonaceous flexible material (such as carbon cloth, carbon paper, carbon film, etc.).

[0009] The present invention also provides a method for preparing the above-mentioned polymer and metal-based oxyhalide composite modified current collector and lithium metal battery, which comprises dissolving the polymer and the metal-based oxyhalide in an organic solvent, stirring them thoroughly until they are evenly mixed to obtain a mixed slurry, and finally coating the mixed slurry on the surface of the lithium metal battery current collector.

[0010] Furthermore, the solvent is one or more of formic acid, ethanol, acetone, isopropanol, tetrahydrofuran, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone and dimethyl sulfoxide.

[0011] Furthermore, the concentration of the polymer and the metal-based oxyhalide in the mixed slurry is 0.5-15%.

[0012] The present invention also provides the application of the above-mentioned polymer and metal-based oxyhalide composite modified current collector and lithium metal battery, which are used to assemble a lithium metal battery. The lithium metal battery includes a positive electrode, a lithium-filled polymer and metal-based oxyhalide composite modified current collector and lithium metal battery, a separator and an electrolyte.

[0013] The positive electrode materials include lithium iron phosphate (LiFePO4), lithium cobalt oxide (LiCO2), ternary materials (LiNi x Co y Mn 1-x-y O2,0≤x≤1,0≤y≤1), lithium nickel manganese oxide (LiNi 0.5 Mn 1.5 O4), copper fluoride (CuF2), ferric fluoride (FeF3·nH2O), ferrous fluoride (FeF2) or sulfur (S).

[0014] Furthermore, the diaphragm is a glass fiber membrane (GF membrane), a polyethylene membrane (PE membrane), a polypropylene membrane (PP membrane), a polyethylene / polypropylene double-layer co-extruded film (PP / PE membrane) or a polypropylene / polyethylene / polypropylene three-layer co-extruded film (PP / PE / PP membrane).

[0015] Furthermore, the electrolyte is an ester electrolyte or an ether electrolyte.

[0016] Compared with the prior art, the present invention has the following advantages and technical effects:

[0017] (1) The modification method of the lithium metal current collector of the present invention is simple in process, easy to operate, and has good repeatability, and is easy to implement large-scale industrial production;

[0018] (2) The modified current collector obtained by uniform coating of the present invention has a stable structure, and the solid electrolyte interface (SEI) film has high mechanical strength and flexibility, which can inhibit the growth of dendrites during the lithium deposition / stripping process. In addition, the lithium halide oxide ion conductor formed in situ during the cycle process is evenly anchored in the polymer matrix, further improving the lithium ion diffusion rate, thereby significantly improving the performance of the battery system. When applied to lithium metal secondary batteries, it can effectively improve the discharge capacity and cycle performance of the corresponding positive electrode materials;

[0019] (3) The current collector modified with a polymer and a metal-based halide oxide of the present invention can promote the electrochemical reaction, promote the uniform deposition of lithium, inhibit the growth of lithium dendrites, and improve the long-term cycle performance of lithium metal batteries, thereby making the entire battery system have higher charge and discharge efficiency, higher discharge specific capacity, longer cycle life and better safety performance, etc., ensuring the stability of the entire system of lithium metal batteries during long cycles, and being able to meet the use requirements of high-energy and high-rate discharge power batteries, greatly promoting the industrialization process of lithium metal batteries, and having broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is an SEM top view of the current collector modified by polymer and metal-based oxyhalide composite in Example 1.

[0021] Figure 2 This is an SEM top view of the current collector modified with a polymer and a metal-based oxyhalide composite in Example 1.

[0022] Figure 3 The charge-discharge curve of the Li||Li symmetrical battery assembled with the polymer and metal-based oxyhalide composite modified current collector after lithium injection in Example 1.

[0023] Figure 4 This is a charge and discharge curve diagram of a Li||Cu battery assembled with a current collector compositely modified with a polymer and a metal-based oxyhalide after lithium injection in Example 2.

[0024] Figure 5 This is a performance cycle diagram of a Li||LFP battery assembled with a current collector modified with a polymer and a metal-based oxyhalide composite after lithium injection in Example 3. DETAILED DESCRIPTION

[0025] The present invention is further described in detail below by way of examples, but is not limited to the examples.

[0026] The experimental methods in the following examples are conventional methods unless otherwise specified.

[0027] Example 1

[0028] Polyvinylidene fluoride-hexafluoropropylene copolymer and bismuth oxychloride were dissolved in N,N-dimethylformamide solution respectively, and after sufficient stirring, a mixed slurry with a mass ratio of 5.0% was obtained. Carbon paper was immersed in the mixed slurry using a hot dipping method at 60°C and kept for 15 minutes. The carbon paper was then taken out and freeze-dried to obtain a current collector modified with a polymer and a metal-based halide oxide composite. The scanning electron microscope image is shown in FIG. Figure 1 、 2 shown.

[0029] The polymer and metal-based oxyhalide composite modified current collector were assembled into a Li||Li symmetric battery. The specific experimental steps were as follows: under the protection of dry argon gas, 20μm lithium sheets of the same shape and size were attached to the surface of the current collector and kept at 200℃ for 1 hour. The assembled Li||Li symmetric battery had a PP separator and a commercial ester electrolyte. At a current density of 1mAcm -2 , deposition capacity of 1 mAh cm -2 Tested under the conditions, the charge and discharge curve is as follows Figure 3 As shown in the figure, bare lithium represents commercial lithium foil, and the composite current collector represents the current collector modified by polymer and metal-based oxyhalide. The symmetrical battery assembled with blank bare lithium can only cycle for 150 hours, and then the polarization increases rapidly. Compared with blank bare lithium, the symmetrical battery assembled with the modified composite current collector can cycle stably for 250 hours. The comparison between the two shows that the current collector modified by polymer and metal-based oxyhalide can effectively inhibit the growth of lithium dendrites and exhibit excellent electrochemical stability.

[0030] Example 2

[0031] Polyvinylidene fluoride-hexafluoropropylene copolymer and indium oxychloride were dissolved in N-methylpyrrolidone solution and prepared into slurries with mass fractions of 5.0% and 3.0%, respectively. The mixed slurry was evenly coated on the copper foil using a coater. After drying at 80°C for 12 hours, a polymer and metal-based halide oxide composite modified current collector was obtained.

[0032] The polymer / metal-based oxyhalide composite modified current collector was assembled into a Li||Cu battery. The separator of the Li||Cu battery was a PP separator and the electrolyte was a commercial ester electrolyte. -2 , deposition capacity of 1 mAh cm -2 Tested under the conditions, the Coulomb efficiency is shown in the figure below Figure 4As shown in the figure, the battery assembled with blank bare lithium can only be cycled 75 times, while the battery assembled with the modified composite current collector can be stably cycled 200 times and maintain a coulombic efficiency of more than 96%. It can be seen that the coulombic efficiency of the Li||Cu battery assembled with the composite current collector is stable, indicating that the current collector modified with a polymer and a metal-based halide oxide can effectively inhibit the growth of lithium dendrites and exhibit excellent electrochemical stability.

[0033] Example 3

[0034] Polymethyl methacrylate and lanthanum oxychloride are dissolved in N,N-dimethylacetamide solution and prepared into a mixed slurry with a mass fraction of 2.5%. The mixed slurry is evenly attached to carbon paper using ultrasonic dispersion method. After freeze-drying, it can be used as a strong SEI film to cover the surface of the carbon paper, obtaining a current collector modified with a polymer and metal-based halide oxide composite.

[0035] Under the protection of dry argon gas, a 50μm lithium sheet of the same shape and size was attached to the surface of the current collector and kept at 220℃ for 2h to obtain a modified current collector after lithium filling. The current collector after lithium filling was matched with the lithium iron phosphate positive electrode material to assemble into a full battery. The diaphragm of the full battery was PP diaphragm and the electrolyte was a commercial ester electrolyte. The performance cycle diagram is shown in FIG. Figure 5 As shown in the figure, the battery assembled with the composite current collector can still maintain a capacity of 99% after 450 cycles at 1C, while the battery assembled with blank bare lithium has a capacity retention rate of only 84% after 120 cycles, indicating that the current collector modified with a composite of polymer and metal-based halide oxide can effectively inhibit the growth of lithium dendrites and exhibit excellent electrochemical stability.

[0036] Example 4

[0037] Polymethyl methacrylate and tantalum oxychloride were dissolved in N,N-dimethylformamide solution and prepared into a mixed slurry with mass fractions of 5% and 3.5%, respectively. The mixed slurry was evenly coated on the copper foil using a coater. After drying at 80°C for 12 hours, a current collector modified with a polymer and metal-based halide oxide composite was obtained.

[0038] Under the protection of dry argon gas, a 40μm lithium sheet of the same shape and size was attached to the surface of the current collector and kept at 230℃ for 1h to obtain the current collector after lithium filling. The Li||Li symmetrical battery was assembled. The separator of the Li||Li symmetrical battery was PE separator and the electrolyte was commercial ether electrolyte. At a current density of 1mAcm -2 , deposition capacity of 1 mAh cm -2Tested under the following conditions, the battery assembled with the modified composite current collector showed a stable charge and discharge curve after 800 hours of cycling, and its voltage platform was symmetrical, while the battery assembled with blank bare lithium could only cycle for 160 hours, indicating that the current collector modified with the polymer / metal-based halide oxide composite can effectively inhibit the growth of lithium dendrites and exhibit excellent electrochemical stability.

[0039] Example 5

[0040] Polymethyl methacrylate and niobium oxychloride are dissolved in dimethyl sulfoxide solution and prepared into a mixed slurry with a mass fraction of 2.0%. Carbon paper is immersed in the mixed slurry using a hot dipping method, maintained at 60°C for 10 minutes, and placed in a drying oven at 60°C for 12 hours to obtain a current collector compositely modified with a polymer and a metal-based halide oxide.

[0041] Under the protection of dry argon gas, a 50μm lithium sheet of the same shape and size was attached to the surface of the current collector and kept at 220℃ for 2h to obtain a modified current collector after lithium filling. The lithium-filled current collector was assembled into a Li||Li symmetric battery. The separator of the Li||Li symmetric battery was PP separator and the electrolyte was commercial ether electrolyte. At a current density of 3mA cm -2 , deposition capacity of 1 mAh cm -2 Under these conditions, a battery assembled with bare lithium could only cycle 90 times, while a battery assembled with the modified composite current collector maintained a stable charge-discharge curve and a symmetrical voltage platform after 500 cycles. This indicates that the current collector modified with a polymer and metal-based oxyhalide composite can effectively inhibit the growth of lithium dendrites, further improving performance and demonstrating excellent electrochemical stability.

[0042] Example 6

[0043] Polytetrafluoroethylene and vanadium oxybromide are dissolved in N,N-dimethylacetamide solution and prepared into a mixed slurry with a mass fraction of 8.0%. The mixed slurry is evenly coated on the surface of copper foil and dried in a drying oven at 60°C for 12 hours to obtain a current collector modified with a polymer and metal-based halide oxide composite.

[0044] Under the protection of dry argon gas, a 60μm lithium sheet of the same shape and size was attached to the surface of the current collector and kept at 220℃ for 3h to obtain a modified current collector after lithium filling. The lithium-filled current collector was mixed with the ternary material LiNi 0.6 Co 0.2 Mn 0.2The modified composite current collector retained 80% of its capacity after 400 cycles at 1C, while the capacity retention of bare lithium was only 68% after 105 cycles. This indicates that the current collector modified with a polymer and metal-based oxyhalide composite can effectively inhibit the growth of lithium dendrites and exhibit excellent electrochemical stability.

[0045] Example 7

[0046] Polyvinylidene fluoride and bismuth oxybromide were dissolved in dimethyl sulfoxide solution and prepared into a mixed slurry with mass fractions of 5% and 1%, respectively. The mixed slurry was evenly coated on the copper foil using a coater. After vacuum drying at 80°C for 24 hours, a current collector modified with a polymer and metal-based halide oxide composite was obtained.

[0047] Under the protection of dry argon gas, a lithium sheet of 80 μm of the same shape and size was attached to the surface of the current collector and kept at 230 ° C for 2 h to obtain a modified current collector after lithium filling. The lithium-filled current collector was assembled into a Li||LiNi 0.8 Co 0.1 Mn 0.1 O2 full battery, Li||LiNi 0.8 Co 0.1 Mn 0.1 The O2 full-cell uses a PP separator and a commercial ester electrolyte. Tested at a 2C rate, the battery assembled with the modified composite current collector maintained a coulombic efficiency of approximately 78% after 350 cycles, while the battery assembled with bare lithium retained only 72% of its capacity after 100 cycles. This demonstrates that the current collector modified with a polymer and metal-based oxyhalide composite effectively inhibits the growth of lithium dendrites and exhibits excellent electrochemical stability.

[0048] Example 8

[0049] Polyaniline and indium oxybromide were dissolved in N-methylpyrrolidone solution and prepared into a mixed slurry with a mass fraction of 1.5%. The mixed slurry was evenly coated on the copper foil using a coater. After drying at 60°C for 12 hours, a current collector modified with a polymer and metal-based halide oxide composite was obtained.

[0050] The polymer and metal-based oxyhalide composite modified current collector was assembled with lithium metal to form a Li||Cu battery. The separator of the Li||Cu battery was GF separator and the electrolyte was commercial ether electrolyte. -2 , deposition capacity of 1 mAh cm -2Under the test conditions, the coulombic efficiency of the battery assembled with the modified composite current collector can still be maintained at about 96% after 300 cycles, while the battery assembled with blank bare lithium can only be cycled 60 times, indicating that the current collector modified by the composite of polymer and metal-based halide oxide can effectively inhibit the growth of lithium dendrites and show excellent electrochemical stability.

[0051] Example 9

[0052] Polyacrylic acid and tungsten oxybromide were dissolved in dimethyl sulfoxide solution and prepared into a mixed slurry with a mass fraction of 1.5%. Carbon paper was immersed in the mixed slurry using a hot dipping method, allowed to stand for 10 minutes, and then taken out and dried at room temperature for 24 hours to obtain a current collector compositely modified with a polymer and a metal-based halide oxide.

[0053] Under the protection of dry argon gas, a lithium sheet of 80 μm of the same shape and size was attached to the surface of the current collector and kept at 210 ° C for 3 hours to obtain a modified current collector after lithium filling. The lithium-filled current collector was assembled into a Li||LiNi 0.8 Co 0.1 Mn 0.1 O2 full battery, Li||LiNi 0.8 Co 0.1 Mn 0.1 The O2 full-cell uses a PP separator and a commercial ether electrolyte. Tested at a 3C rate, the battery assembled with the modified composite current collector retained 85% of its capacity after 400 cycles. In comparison, the bare lithium battery could only cycle 110 times with a capacity retention of only 78%. This demonstrates that the current collector modified with a polymer and metal-based oxyhalide composite effectively inhibits the growth of lithium dendrites and exhibits excellent electrochemical stability.

[0054] Example 10

[0055] Polyvinylidene fluoride-hexafluoropropylene copolymer and lanthanum bromide were dissolved in acetone solution and prepared into a mixed slurry with a mass fraction of 2%. Carbon paper was immersed in the mixed slurry using ultrasonic dispersion method and ultrasonicated for 15 minutes. After vacuum drying at 85°C for 12 hours, a current collector modified with a polymer and metal-based halide oxide composite was obtained.

[0056] Under the protection of dry argon, a 70μm lithium sheet of the same shape and size was attached to the surface of this current collector and kept at 200°C for 3 hours to obtain a modified current collector after lithium filling. This lithium-filled current collector was then assembled into a Li||LiFePO4 full cell using a PP separator and a commercial ester electrolyte. Tested at a rate of 5C, the battery assembled with the modified composite current collector maintained a capacity retention rate of over 80% after 800 cycles. In comparison, the battery assembled with bare lithium retained a capacity of over 80% after 200 cycles. This demonstrates that the current collector modified with a polymer and metal-based oxyhalide composite effectively inhibits the growth of lithium dendrites and exhibits excellent electrochemical stability.

[0057] Example 11

[0058] Polytetrafluoroethylene and bismuth iodide oxide were dissolved in isopropanol solution and prepared into a mixed slurry with a mass fraction of 3%. The mixed slurry was evenly coated on the copper foil using a coater. After freeze-drying for 24 hours, a current collector modified with a polymer and metal-based halide oxide composite was obtained.

[0059] The polymer and metal-based oxyhalide composite modified current collector was assembled with lithium metal to form a Li||Cu battery. The separator of the Li||Cu battery was GF separator and the electrolyte was commercial ether electrolyte. -2 , deposition capacity of 1 mAh cm -2 Under the test conditions, the coulombic efficiency of the battery assembled with the modified composite current collector can still be maintained at about 98% after 250 cycles. In comparison, the battery assembled with blank bare lithium can only be cycled 70 times, and the coulombic efficiency is only 95%, indicating that the current collector modified by the composite of polymer and metal-based halide oxide can effectively inhibit the growth of lithium dendrites and show excellent electrochemical stability.

[0060] Example 12

[0061] Polytetrafluoroethylene and lanthanum iodide are dissolved in tetrahydrofuran solution and prepared into a mixed slurry with a mass fraction of 4%. The mixed slurry is evenly coated on a copper foil and dried at room temperature for 12 hours to obtain a current collector compositely modified with a polymer and a metal-based halide oxide.

[0062] Under dry argon, an 80μm lithium sheet of the same shape and size was attached to the surface of this current collector and maintained at 200°C for 2 hours to obtain a modified current collector after lithium filling. This lithium-filled current collector was then assembled into a Li||LiFePO4 full cell using a GF separator and a commercial ester electrolyte. Tested at a rate of 5C, the cell assembled with the modified composite current collector maintained a capacity retention of approximately 82% after 400 cycles. In comparison, a cell assembled with bare lithium could only cycle 200 times, with a capacity retention of only 79%. This demonstrates that the current collector modified with a polymer and metal-based oxyhalide composite effectively inhibits the growth of lithium dendrites and exhibits excellent electrochemical stability.

Claims

1. A current collector and a lithium metal battery modified by a polymer and a metal-based oxyhalide composite, characterized in that: A slurry prepared by dissolving a polymer and a metal-based halide oxide in an organic solvent is attached to the surface of the lithium metal battery current collector, and then lithium is injected into the current collector.

2. The polymer and metal-based oxyhalide composite modified current collector and lithium metal battery according to claim 1, characterized in that: The oxyhalide is one or more of bismuth oxychloride (BiOCl), indium oxychloride (InOCl), vanadium oxychloride (VOCl2, VOCl3), tantalum oxychloride (TaOCl3), niobium oxychloride (NbOCl3), molybdenum oxychloride (MoOCl4, MoO2Cl2), tungsten oxychloride (WOCl4, WO2Cl2), lanthanum oxychloride (LaOCl), bismuth oxybromide (BiOBr), indium oxybromide (InOBr), vanadium oxybromide (VOBr3), niobium oxybromide (NbOBr3), tungsten oxybromide (WOBr4), lanthanum oxybromide (LaOBr), bismuth oxyiodide (BiOI), and lanthanum oxyiodide (LaOI).

3. The polymer and metal-based oxyhalide composite modified current collector and lithium metal battery according to claim 1, characterized in that: The solvent is one or more of formic acid, ethanol, acetone, isopropanol, tetrahydrofuran, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone and dimethyl sulfoxide.

4. The polymer and metal-based oxyhalide composite modified current collector and lithium metal battery according to claim 1, characterized in that: The polymer is one or more of polyvinylidene fluoride-hexafluoropropylene copolymer, polymethyl methacrylate, polyvinylidene fluoride, polyacrylic acid, polytetrafluoroethylene, polyaniline, polypyrrole, polythiophene and derivatives thereof.

5. The polymer and metal-based oxyhalide composite modified current collector and lithium metal battery according to claim 1, characterized in that: The lithium metal battery current collector is copper foil, aluminum foil or carbon flexible material.

6. The polymer and metal-based oxyhalide composite modified current collector and lithium metal battery according to claim 1, characterized in that: The amount of lithium injected into the current collector is 0-20 mAh cm -2 .

7. The polymer and metal-based oxyhalide composite modified current collector and lithium metal battery according to claim 1, characterized in that: The drying methods used for the prepared current collector include freeze drying, room temperature drying, and heating drying.

8. The polymer and metal-based oxyhalide composite modified current collector and lithium metal battery according to claim 1, characterized in that: The coating method selected for the prepared current collector includes ultrasonic dispersion method, dipping method, stirring method, mechanical or manual coating.

9. The method for preparing the polymer-metal-based oxyhalide composite-modified current collector and lithium metal battery according to any one of claims 1 to 8, characterized in that: The polymer and the metal-based halide oxide are dissolved in an organic solvent, stirred thoroughly until the mixture is uniform, and a mixed slurry is obtained. Finally, the mixed slurry is evenly attached to the surface of the lithium metal battery current collector.

10. Use of a polymer and metal-based oxyhalide composite modified current collector and lithium metal battery according to any one of claims 1 to 6, or a polymer and metal-based oxyhalide composite modified current collector and lithium metal battery prepared by the preparation method according to any one of claims 7 to 8, characterized in that: The lithium metal battery is assembled into a lithium metal battery, which includes a positive electrode, a current collector compositely modified by a lithium-filled polymer and a metal-based halide oxide, a separator and an electrolyte.

11. The polymer and metal-based oxyhalide composite modified current collector according to claim 10 is used in lithium metal batteries, characterized in that: The positive electrode materials include lithium iron phosphate (LiFePO4), lithium cobalt oxide (LiCoO2), ternary materials (LiNi x Co y Mn 1-x-y O2,0≤x≤1,0≤y≤1), lithium nickel manganese oxide (LiNi 0.5 Mn 1.5 O4), copper fluoride (CuF2), ferric fluoride (FeF3·nH2O), ferrous fluoride (FeF2) or sulfur (S). The diaphragm is a glass fiber (GF) film, a polyethylene (PE) film, a polypropylene (PP) film, a polyethylene / polypropylene double-layer co-extruded (PP / PE) film, or a polypropylene / polyethylene / polypropylene three-layer co-extruded (PP / PE / PP) film. The electrolyte is an ester electrolyte or an ether electrolyte.

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