Metallic lithium negative electrode high-entropy current collector and preparation method and application thereof

Abstract

The application belongs to the technical field of lithium metal battery preparation, and particularly relates to a metal lithium negative electrode high-entropy current collector and a preparation method and application thereof. The preparation method of the metal lithium negative electrode high-entropy current collector comprises the following steps: taking a current collector as a substrate, using a first magnetron sputtering mode to sputter a high-entropy alloy target material on the current collector substrate to construct a high-entropy coating; using a second magnetron sputtering mode to sputter a metal lithium target material on the surface of the high-entropy current collector to deposit a metal lithium film layer; and obtaining the metal lithium negative electrode high-entropy current collector. The high-entropy coating is deposited on the current collector substrate through magnetron sputtering. Due to the physical and chemical properties of the high-entropy coating, the composition of the high-entropy coating is adjusted to adjust the surface energy state, thereby the nucleation potential barrier of lithium is reduced, the nucleation and growth process of lithium is adjusted, and lithium is uniformly deposited on the current collector to ensure the cycle stability and cycle coulombic efficiency of the high-specific-energy metal lithium negative electrode.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of lithium metal battery preparation, and particularly relates to a high-entropy current collector for a lithium metal negative electrode and a preparation method and application thereof. BACKGROUND

[0002] With the rapid development of social economy, new energy electric vehicles, portable electronic devices and other electronic devices are increasingly favored by people. Therefore, in recent years, the research on energy batteries has become a current research hotspot. According to the research data in recent years, the current lithium ion battery with graphite as the negative electrode has been very close to its theoretical capacity, and it is difficult to have a greater improvement. If lithium metal is used to replace graphite as the negative electrode material, the negative electrode specific capacity will be more than ten times improved. However, the wide use of high-capacity lithium metal negative electrode still has some problems. Among them, the lithium dendrite growth is one of the key problems, that is, the lithium metal negative electrode will form irregular lithium dendrites in the lithium deposition / dissolution process. This dendritic growth mode will cause several important problems: (1) the lithium dendrites will pierce the separator and cause short circuit of the battery when they grow to a certain extent, which has serious safety hazards; (2) at the same time, with the continuous deposition of lithium metal, the solid electrolyte interface film on the surface of the negative electrode material will repeatedly break and form again, continuously consuming active lithium and reducing its coulombic efficiency; (3) in addition, irreversible capacity loss will also be caused. Therefore, controlling the growth process of lithium dendrites is the current research focus.

[0003] At present, there are mainly four strategies with promising research prospects to deal with the growth problem of lithium metal dendrites: (1) optimization of the lithium metal negative electrode solid-state electrolyte interface; (2) use of solid electrolyte; (3) structural design of three-dimensional lithium metal negative electrode; (4) optimization and improvement of the separator. However, most of the above-mentioned schemes are to inhibit the growth of dendrites through physical hindering effect, and only a small part considers the root cause of lithium dendrite growth, which does not fundamentally solve the problem, and is easy to cause short circuit due to the penetration of lithium dendrites through the separator and contact with the positive electrode, as well as poor cycle life and coulombic efficiency. SUMMARY

[0004] The application aims to provide a metal lithium negative electrode high-entropy current collector and a preparation method and application thereof. A high-entropy coating is constructed on the current collector by a magnetron sputtering technology to induce metal lithium nucleation and growth, so that metal lithium is deposited in a dendrite-free process, and metal lithium is uniformly deposited on the negative electrode side, thus preventing lithium dendrite from growing freely and avoiding the short circuit caused by the penetration of lithium dendrite through the separator and the positive electrode, improving the cycle life and coulombic efficiency of high-specific-energy lithium batteries, and preventing safety hazards. A controllable thickness of metal lithium film is deposited on the surface of the prepared high-entropy current collector by the magnetron sputtering technology, thus overcoming the technical difficulty of preparing an ultrathin lithium foil caused by the insufficient ductility of metal lithium. The deposition of the metal lithium foil by the magnetron sputtering technology also helps to improve the interface contact between the metal lithium and the current collector and reduce the contact resistance.

[0005] To achieve the above-mentioned purposes, the application solves the above-mentioned technical problems by the following technical scheme.

[0006] The first object of the application is to provide a preparation method of a metal lithium negative electrode high-entropy current collector, which comprises the following steps:

[0007] The high-entropy alloy target is sputtered on the current collector substrate by a first magnetron sputtering method to construct a high-entropy coating.

[0008] The metal lithium target is sputtered on the surface of the high-entropy current collector by a second magnetron sputtering method to deposit a metal lithium film, thus obtaining a metal lithium negative electrode high-entropy current collector.

[0009] Further, the high-entropy elements in the high-entropy coating are three or more than three of scandium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, yttrium, zirconium, niobium, molybdenum, technetium, ruthenium, rhodium, hafnium, tantalum, tungsten, rhenium, lanthanum, cerium, praseodymium, neodymium, promethium, samarium, and the atomic percentage of each high-entropy element is equal, and the sum of the atomic percentages of the high-entropy elements is 100%.

[0010] Further, the high-entropy coating is a high-entropy alloy coating, a high-entropy alloy oxide coating or a high-entropy alloy nitride coating.

[0011] Further, the gas for magnetron sputtering in the process of sputtering the high-entropy alloy target on the current collector substrate is argon, oxygen or nitrogen, and the gas pressure is 0.25 Pa to 0.35 Pa. When the gas for magnetron sputtering is argon, the high-entropy coating is a high-entropy alloy coating. When the gas for magnetron sputtering is oxygen, the high-entropy coating is a high-entropy alloy oxide coating. When the gas for magnetron sputtering is nitrogen, the high-entropy coating is a high-entropy alloy nitride coating. The gas for magnetron sputtering in the process of sputtering the metal lithium target on the surface of the high-entropy current collector is argon, and the gas pressure is 0.25 Pa to 0.35 Pa.

[0012] Further, the current collector substrate is a copper foil, a polymer-based composite copper foil or an aluminum-copper composite substrate.

[0013] Further, the method comprises the following steps:

[0014] The raw materials of high-entropy elements are mixed in an atomic ratio, ball-milled, and then sintered by a flash method to obtain the high-entropy alloy target material, the purity of which is greater than or equal to 99.99%.

[0015] The current collector substrate is installed on a sample roller, the high-entropy alloy target material is cleaned with acetone and then dried, is assembled at a magnetron sputtering cathode, is pre-sputtered for 5 minutes to remove oxides and other impurities on the surface of the target material, and then is subjected to direct-current magnetron reaction sputtering to sputter the high-entropy alloy target material on the current collector substrate.

[0016] Then, the metal lithium target material is sputtered on the surface of the high-entropy current collector by using a winding type direct-current magnetron reaction sputtering device, the current collector substrate with the sputtered high-entropy coating is installed on a sample roller, the metal lithium target material is cleaned with acetone and then dried, is assembled at a magnetron sputtering cathode, is pre-sputtered for 5 minutes to remove oxides and other impurities on the surface of the target material, and then is subjected to direct-current magnetron reaction sputtering to sputter the metal lithium target material on the surface of the high-entropy current collector, thereby obtaining the metal lithium negative electrode high-entropy current collector.

[0017] Further, the raw materials of high-entropy elements are obtained from elemental metal powders or / and alloy metal powders, and the purity of the elemental metal powders and the alloy metal powders is not less than 99.99%.

[0018] Further, during the direct-current magnetron reaction sputtering process, the vacuum degree of the magnetron sputtering is 9.9*10 -5 Pa~50*10 - 5 Pa, the target distance is 20 cm~50 cm, the sputtering temperature is 20℃~30℃, and the unwinding / reeling speed of the winding roller is 5 rpm~10 rpm.

[0019] The second object of the present application is to provide the metal lithium negative electrode high-entropy current collector prepared by the above preparation method, wherein the thickness of the high-entropy coating is 20 nm~200 nm, and the thickness of the metal lithium film layer is 5μm~30μm.

[0020] The third object of the present application is to provide the application of the above metal lithium negative electrode high-entropy current collector in a lithium battery, wherein the lithium battery comprises a positive electrode, a separator, a metal lithium negative electrode high-entropy current collector and an electrolyte, the positive electrode is one of lithium cobaltate, nickel-manganese-cobaltate, nickel-aluminum-cobaltate and lithium-rich manganese-based material, the separator is a polyethylene separator or a polypropylene microporous separator, and the electrolyte is a mixed solution of lithium hexafluorophosphate, dimethyl carbonate and diethyl carbonate.

[0021] Further, the preparation process of the positive electrode comprises the following steps: dispersing the positive electrode material, Super-P and polyvinylidene fluoride in N-methyl pyrrolidone by vacuum stirring at a mass ratio of 90:5:5 to form a positive electrode slurry with a viscosity of 1 Pa·s~10 Pa·s, coating the positive electrode slurry on the surface of an aluminum foil material, and preparing a positive electrode sheet by roll pressing after vacuum drying at 100 DEG C for 2h, wherein the prepared positive electrode surface loading is 1 mAh / cm 2 ~5 mAh / cm 2 .

[0022] Further, the concentration of lithium hexafluorophosphate in the electrolyte is 1 mol / L~5 mol / L, and the volume ratio of dimethyl carbonate and diethyl carbonate is 1:1.

[0023] Compared with the prior art, the present application has the following beneficial effects:

[0024] (1) The present application provides a preparation method of a lithium battery ultra-thin metal lithium negative electrode high-entropy current collector, a high-entropy coating is constructed on the current collector substrate by a magnetron sputtering method, and a metal lithium film layer is deposited on the surface of the high-entropy coating to form a metal lithium negative electrode high-entropy current collector. The high-entropy coating induces the nucleation and growth of metal lithium, so that the metal lithium undergoes a dendrite-free deposition process to form a metal lithium film layer, ensuring that the metal lithium can be uniformly deposited on the negative electrode side, thereby preventing the free growth of lithium dendrites at the root and avoiding the phenomenon of short circuit caused by the penetration of lithium dendrites through the separator and contacting the positive electrode. Based on thermodynamics and kinetics, the present application enables lithium to be uniformly deposited on the side of the current collector attached with a nanoscale high-entropy coating, thereby achieving spatial control of the lithium deposition process. The addition of the functional high-entropy coating reduces the free growth of lithium dendrites, eliminates the possibility of short circuit caused by the penetration of lithium dendrites through the separator and contacting the positive electrode, improves the coulombic efficiency and cycle life, and reduces the capacity decay.

[0025] (2) The high-entropy coating provided by the present application has a complex lattice structure, which produces significant lattice distortion, resulting in a large number of dislocations and defects. At the same time, the uniform distribution of constituent elements induces an increase in configurational entropy, thereby producing a high-entropy effect. In addition, the performance of the alloy benefits from the synergistic effect of different constituent elements, exceeding that of single-element materials and traditional alloy materials. These characteristics of high-entropy materials result in some unique properties, such as the generation of multiple lithium ion transmission paths, active sites and high ionic conductivity. Compared with traditional alloys, the synergistic effect of multiple elements in high-entropy materials can adjust the lithium affinity to increase the adsorption and diffusion energy, thereby promoting the uniformity of lithium deposition.

[0026] (2) The application discloses a preparation method of a lithium battery ultra-thin metal lithium negative electrode high-entropy current collector, which comprises the following steps: depositing a nano high-entropy alloy coating, a high-entropy oxide coating or a high-entropy nitride coating on the surface of an existing current collector substrate by a direct current magnetron sputtering process, and then depositing an ultra-thin metal lithium layer. Due to the physical and chemical properties of the high-entropy coating, the surface energy state can be regulated by regulating the composition of the high-entropy coating. Then the nucleation potential barrier of lithium can be reduced, and the nucleation and growth process of lithium can be regulated, so that lithium is uniformly deposited on the current collector to ensure the cycle stability and cycle coulombic efficiency of the high-specific-energy metal lithium negative electrode. It is found that the charge-discharge cycle performance of the lithium battery using the current collector is obviously improved, and the coulombic efficiency remains at a high level after 200 cycles. Therefore, the use of the current collector improves the safety performance of the battery and also improves the cycle life and coulombic efficiency of the battery. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 The cycle coulombic efficiency of the metal lithium negative electrode in the embodiment 1 of the application. DETAILED DESCRIPTION

[0028] The technical solutions in the embodiments of the application will be clearly and completely described below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the application.

[0029] It should be noted that the professional terms used in the application are only for the purpose of describing the specific embodiments, and are not intended to limit the protection scope of the application. Unless otherwise specified, the various raw materials, reagents, instruments and equipment used in the following embodiments of the application can be purchased from the market or prepared by the existing method.

[0030] Currently, there are mainly the following ways to deal with the lithium metal dendrite growth problem: (1) optimization of the lithium metal negative electrode solid-state electrolyte interface; (2) use of solid electrolyte; (3) three-dimensional lithium metal negative electrode structure design; (4) optimization and improvement of the separator. However, most of the above-mentioned solutions are to inhibit the growth of dendrites through physical hindering, and only a small part considers the root cause of lithium dendrite growth, that is, its nucleation process. The nucleation process of lithium dendrites occurs during electrochemical deposition. In addition, due to the existence of non-uniform electric field and lithium ion flux in the liquid electrolyte system, the nucleation is usually non-uniform, which to some extent promotes the growth process of lithium dendrites. Therefore, the present application provides an excellent high specific energy lithium battery ultra-thin metal lithium negative electrode and high-entropy current collector integrated structure, a preparation method thereof, and a lithium battery using the ultra-thin metal lithium negative electrode high-entropy current collector.

[0031] Based on the above problems, the present application provides a preparation method of a metal lithium negative electrode high-entropy current collector, comprising the following steps:

[0032] The high-entropy alloy target material is sputtered on the current collector substrate by the first magnetron sputtering method to construct a high-entropy coating.

[0033] The metal lithium target material is sputtered on the surface of the high-entropy current collector by the second magnetron sputtering method to deposit a metal lithium film layer; that is, a metal lithium negative electrode high-entropy current collector is obtained.

[0034] The present application provides a preparation method of a lithium battery ultra-thin metal lithium negative electrode high-entropy current collector. The high-entropy coating is constructed on the current collector substrate by the magnetron sputtering method, and a metal lithium film layer is deposited on the surface of the high-entropy coating to form a metal lithium negative electrode high-entropy current collector. The high-entropy coating induces the nucleation and growth of metal lithium, so that the metal lithium undergoes a dendrite-free deposition process to form a metal lithium film layer, ensuring that the metal lithium can be uniformly deposited on the negative electrode side, thereby preventing the free growth of lithium dendrites and avoiding the short circuit phenomenon caused by the penetration of lithium dendrites through the separator and contact with the positive electrode. Based on thermodynamics and kinetics, the present application prepares a nanoscale high-entropy coating on the surface of the negative electrode current collector, so that lithium can be uniformly deposited on the side of the current collector attached with the nanoscale high-entropy coating, thereby achieving spatial control of the lithium deposition process. The addition of the functional high-entropy coating reduces the free growth of lithium dendrites, eliminates the possibility of short circuit caused by the penetration of lithium dendrites through the separator and contact with the positive electrode, improves the coulombic efficiency and cycle life, and reduces the capacity decay.

[0035] Compared with the prior art, the present application is based on thermodynamics and kinetics, and makes lithium uniformly deposit on the side of the current collector attached with the nanoscale high-entropy coating, so as to control the lithium deposition process in space. The addition of the functional high-entropy coating reduces the free growth of lithium dendrites, eliminates the possibility of short circuit caused by the penetration of lithium dendrites through the separator to contact the positive electrode, improves the coulombic efficiency and cycle life, and reduces the capacity decay.

[0036] In a specific embodiment, the high-entropy elements in the high-entropy coating are three or more of scandium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, yttrium, zirconium, niobium, molybdenum, technetium, ruthenium, rhodium, hafnium, tantalum, tungsten, rhenium, lanthanum, cerium, praseodymium, neodymium, promethium, samarium, and the atomic percentage of each high-entropy element in the high-entropy coating is equal, and the sum of the atomic percentages of the high-entropy elements is 100%.

[0037] The lithium battery ultra-thin metal lithium negative electrode high-entropy current collector provided by the present application has a complex lattice structure, which causes obvious lattice distortion, thereby generating a large number of dislocations and defects; at the same time, the uniform distribution of the constituent elements induces an increase in configuration entropy, thereby generating a high-entropy effect. In addition, the performance of the alloy benefits from the synergistic effect of different constituent elements, which exceeds that of single-element materials and traditional alloy materials. These characteristics of high-entropy materials result in some unique properties, such as the generation of multiple lithium ion transmission paths, active sites, and high ionic conductivity. Compared with traditional alloys, the synergistic effect of multiple elements of high-entropy materials can adjust the lithiumophilic property to increase the adsorption and diffusion energy, thereby promoting the uniformity of lithium deposition. Therefore, the development of a high-entropy negative electrode current collector is crucial for realizing uniform lithium deposition with ultra-stable performance.

[0038] In a specific embodiment, the high-entropy coating is a high-entropy alloy coating, a high-entropy alloy oxide coating, or a high-entropy alloy nitride coating. The entropy coating of the present application is a nanoscale high-entropy coating, and each component element of the high-entropy coating is sputter-deposited on the current collector substrate by magnetron sputtering to form a high-entropy coating. The physical and chemical properties of the high-entropy coating itself are adjusted by adjusting the composition of the high-entropy coating to adjust the surface energy state, thereby reducing the nucleation barrier of lithium, adjusting the nucleation and growth process, and making lithium uniformly deposit on the current collector to ensure the cycle stability and cycle coulombic efficiency of the high-specific-energy metal lithium negative electrode.

[0039] In a specific embodiment, during the sputtering of the high-entropy alloy target on the current collector substrate, the vacuum degree of the magnetron sputtering is 9.9x10 -5 Pa~50x10 -5Pa~50×10 -5 Pa, the sputtering temperature is 20°C~30°C, and the unwinding / winding speed of the roller is 5 rpm~10 rpm.

[0040] In a specific embodiment, the vacuum degree of the magnetron sputtering is 9.9×10 -5 Pa~50×10 -5 Pa, the sputtering temperature is 20°C~30°C, and the unwinding / winding speed of the roller is 5 rpm~10 rpm.

[0041] In a specific embodiment, when the gas for magnetron sputtering is argon, the high-entropy coating is a high-entropy alloy coating, when the gas for magnetron sputtering is oxygen, the high-entropy coating is a high-entropy alloy oxide coating, and when the gas for magnetron sputtering is nitrogen, the high-entropy coating is a high-entropy alloy nitride coating.

[0042] In a specific embodiment, the current collector substrate is a cold-rolled copper foil, a polymer-based composite copper foil, or an aluminum-copper composite current collector. In the present application, the cold-rolled copper foil is a pure copper foil, and the polymer in the polymer-based composite copper foil can be polyacrylonitrile or polymethyl methacrylate.

[0043] In a specific embodiment, the method for preparing a metal lithium negative electrode high-entropy current collector specifically comprises the following steps:

[0044] The raw materials of high-entropy elements are mixed in an atomic ratio, ball-milled, and then burned by a flash method to form a high-entropy alloy target material, and the purity of the high-entropy alloy target material is ≥99.99%.

[0045] A winding type direct current magnetron reaction device is used, the current collector substrate is installed on a sample roller, the high-entropy alloy target material is cleaned with acetone and then dried, is assembled at a magnetron sputtering cathode, is pre-sputtered for 5 min to remove surface oxides and other impurities, and then is subjected to direct current magnetron reaction sputtering to sputter the high-entropy alloy target material on the current collector substrate.

[0046] Then, the metal lithium target material is sputtered on the high-entropy current collector surface by using a winding type direct current magnetron reaction sputtering, the current collector substrate with the sputtered high-entropy coating is installed on a sample roller, the metal lithium target material is cleaned with acetone and then dried, is assembled at a magnetron sputtering cathode, is pre-sputtered for 5 min to remove surface oxides and other impurities, and then is subjected to direct current magnetron reaction sputtering to sputter the metal lithium target material on the high-entropy current collector surface to obtain a metal lithium negative electrode high-entropy current collector.

[0047] In the present application, the flash sintering method is a field-assisted ceramic sintering method, a stable electric field is applied to the material, and the furnace temperature is raised at a constant rate. When the furnace temperature is low, the material has a high resistivity, and the current flowing through the material is very small. As the furnace temperature rises, the sample resistivity decreases, and the current gradually increases. This stage is called the incubation stage, and the system is voltage-controlled. When the furnace temperature rises to the critical temperature, the material resistivity drops sharply, and the current rises sharply, and flash sintering occurs. Since the field strength is still stable at this time, the system power (W=EJ) will quickly reach the upper limit of the electric power of the power supply, and the system will change from voltage control to current control, which is called the flash sintering stage. In the present application, the flash sintering method is the existing conventional technology, as long as the high-entropy alloy target material can be formed, the present application will not be further described.

[0048] The present application deposits a nanoscale high-entropy alloy coating, a high-entropy oxide coating or a high-entropy nitride coating on the surface of the existing current collector substrate by a direct current magnetron sputtering process, and then deposits an ultra-thin metal lithium layer. It is found that the lithium battery using the current collector has significantly improved charge-discharge cycle performance, and the coulomb efficiency remains at a high level after 200 cycles. Therefore, the battery using the current collector improves the safety performance of the battery and also improves the cycle life and coulomb efficiency.

[0049] In a specific embodiment, the raw material of the high-entropy element is derived from elemental metal powder or / and alloy metal powder, and the purity of the elemental metal powder and the alloy metal powder is not less than 99.99%.

[0050] The present application also provides a metal lithium negative electrode high-entropy current collector prepared by the above preparation method. In the present application, the thickness of the high-entropy coating can be any value between 20 nm and 200 nm, such as 20 nm, 50 nm, 100 nm, 150 nm or 200 nm, and the thickness of the metal lithium film layer can be any value between 5 μm and 30 μm, such as 5 μm, 10 μm, 15 μm, 20 μm, 25 μm or 30 μm, but is not limited to the specific values listed above. Other values not listed in the above value range are also applicable, and will not be described here.

[0051] In addition, the present application also provides the application of the metal lithium negative electrode high-entropy current collector in a lithium battery. The lithium battery is composed of a positive electrode, a separator, a metal lithium negative electrode high-entropy current collector and an electrolyte. The positive electrode is one of lithium cobaltate, nickel-manganese-cobaltate, nickel-aluminum-cobaltate and lithium-rich manganese-based material. The separator is a polyethylene separator or a polypropylene microporous separator. The electrolyte is a mixture of lithium hexafluorophosphate, dimethyl carbonate and diethyl carbonate.

[0052] In a specific embodiment, the preparation process of the positive electrode comprises the following steps: dispersing the positive electrode material, the Super-P conductive agent and the polyvinylidene fluoride in N-methylpyrrolidone by vacuum stirring at a mass ratio of 90:5:5 to form a positive electrode slurry with a viscosity of 1 Pa·s~10 Pa·s, coating the positive electrode slurry onto the surface of an aluminum foil material, and preparing a positive electrode sheet by roll pressing after vacuum drying at a temperature of 100℃ for 2h, wherein the prepared positive electrode has a surface loading of 1 mAh / cm 2 ~5 mAh / cm 2 .

[0053] In a specific embodiment, the concentration of lithium hexafluorophosphate in the electrolyte is 1~5 mol / L, and the volume ratio of dimethyl carbonate to diethyl carbonate is 1:1.

[0054] The following is further illustrated by specific embodiments.

[0055] Example 1

[0056] Preparation of ultra-thin metal lithium negative electrode niobium molybdenum tantalum hafnium high-entropy current collector (Li-NbMoTaHf-Cu) and its application in NCM811 full battery, including the following steps:

[0057] S1, NbMoTaHf high-entropy alloy target sintering

[0058] The Nb, Mo, Ta, and Hf metal powders with a purity of 99.99% were dispersed in acetone according to a mass ratio of 1:1:1:1 and mixed using a planetary ball mill. Then, the dried mixed metal powder was pressed into the desired size of the sputtering target and sintered into a NbMoTaHf high-entropy alloy target for sputtering by flash sintering, and the purity of the target was ≥99.99%.

[0059] S2, preparation of NbMoTaHf-Cu high-entropy current collector

[0060] The pre-purchased copper foil substrate (commercialized copper foil) was mounted on the sample roller, and the niobium molybdenum tantalum hafnium high-entropy alloy target was cleaned with acetone and then dried before being assembled at the magnetron sputtering cathode. The target was pre-sputtered for 5 min to remove the surface oxides and other impurities. The sample feeding roller and the sample collecting roller were opened, the speed was set to 5 rpm, the niobium molybdenum tantalum hafnium high-entropy alloy target cathode power was turned on, and the niobium molybdenum tantalum hafnium high-entropy alloy was sputtered to form a NbMoTaHf high-entropy alloy coating, thereby preparing a NbMoTaHf-Cu current collector. The thickness of the copper foil substrate was 12 μm, the thickness of the NbMoTaHf high-entropy alloy coating was 50 nm, and the process parameters of magnetron sputtering were as follows: the vacuum degree was 5.0×10 -4Pa, sputtering power 120 W, working pressure 0.35 Pa, working gas argon, target distance 40 cm, sputtering temperature 25℃.

[0061] S3, preparation of ultra-thin metal lithium negative electrode high-entropy current collector integrated structure Li-NbMoTaHf-Cu

[0062] An ultra-thin metal lithium negative electrode was deposited on the surface of the above-mentioned NbMoTaHf-Cu current collector by magnetron sputtering technology, and the sample roller speed was set to 5 rpm. The process parameters of magnetron sputtering were as follows: base vacuum degree 5.0×10 -4 Pa, sputtering power 70 W, working pressure 0.35 Pa, working gas argon, target distance 40 cm, sputtering temperature 25℃. The thickness of the deposited metal lithium was 30 μm. The Li-NbMoTaHf-Cu current collector loaded with the ultra-thin metal lithium negative electrode was punched to the required shape for subsequent NCM811 full battery assembly needs.

[0063] S4, preparation of NCM811-Al positive electrode

[0064] The NCM811 positive electrode material powder, Super-P conductive agent and polyvinylidene fluoride were dispersed in N-methylpyrrolidone by vacuum stirring at a mass ratio of 90:5:5 to form an NCM811 slurry with a viscosity of 5 Pa·s. The above positive electrode slurry was blade-coated onto the surface of an aluminum foil, vacuum dried at a temperature of 100℃ for 2h, and then rolled and punched to the required shape to prepare an Al-NCM811 positive electrode sheet. The prepared positive electrode surface loading was 5 mAh / cm 2 .

[0065] S5, preparation of electrolyte

[0066] Equal volumes of dimethyl carbonate and diethyl carbonate were mixed, and lithium hexafluorophosphate was dispersed in the mixed solution to prepare an electrolyte solution with a lithium hexafluorophosphate concentration of 1 mol / L.

[0067] S6, assembly of high-energy lithium battery Al-NCM811|Li-NbMoTaHf-Cu cell

[0068] 10 pieces of the ultra-thin metal lithium negative electrode high-entropy current collector integrated structure Li-NbMoTaHf-Cu prepared in S3, 11 pieces of the positive electrode NCM811-Al prepared in S4, and a polyethylene separator were stacked to prepare a high-energy lithium battery cell, and then the cell was placed in a pre-stamped aluminum plastic bag. After drying at 100°C for 20h, the electrolyte prepared in S5 was injected, and the amount of electrolyte added was 3g / Ah. Then, the prepared Al-NCM811|Li-NbMoTaHf-Cu cell was subjected to formation treatment, and the formation process was as follows: constant current and constant voltage charging at a rate of 0.1C to 4.3V, and constant current discharging at a rate of 0.1C to 3.0V. After the formation treatment, the cell was exhausted and finally sealed, labeled and stored.

[0069] It was found through charge and discharge comparison tests of the original copper foil and the ultra-thin metal lithium negative electrode high-entropy current collector integrated structure prepared in Example 1 that after the NbMoTaHf high-entropy alloy coating of the application was sputtered on the current collector, the nucleation barrier of lithium was reduced, thereby enabling spatial control of lithium deposition, allowing lithium to be uniformly deposited on the current collector with the NbMoTaHf high-entropy alloy coating attached. This function prevents the free growth of lithium dendrites, thereby avoiding safety hazards such as internal short circuits caused by dendrite contact with the positive electrode. The charge and discharge cycle performance of the metal lithium negative electrode was significantly improved, specifically, as the number of cycles increased, the capacity of the battery remained stable, and after 200 cycles, the coulombic efficiency remained at a high level.

[0070] Example 2

[0071] An ultra-thin metal lithium negative electrode tantalum niobium hafnium zirconium high-entropy current collector (Li-TaNbHfZr-Cu) was prepared and applied in an NCM811 full battery, including the following steps:

[0072] S1, TaNbHfZr high-entropy alloy target preparation

[0073] Nb, Zr, Ta, and Hf metal powders with a purity of 99.99% were dispersed in acetone according to a mass ratio of 1:1:1:1, and mixed using a planetary ball mill. Then, the mixed metal powder was pressed into the desired size of the sputtering target and sintered into a sputtering TaNbHfZr high-entropy alloy target using a flash sintering method, and the purity of the target was ≥99.99%.

[0074] S2, TaNbHfZr-Cu high-entropy current collector preparation

[0075] The pre-purchased copper foil is loaded on the sample roller, and the pre-prepared tantalum niobium hafnium zirconium high-entropy alloy target is cleaned with acetone and dried before being assembled into the magnetron sputtering cathode. The target is pre-sputtered for 5 min to remove the surface oxides and other impurities. The sample feeding roller and the sample collecting roller are opened, and the speed is set to 5 rpm. The niobium molybdenum tantalum hafnium high-entropy alloy target cathode power is turned on to start sputtering the niobium molybdenum tantalum hafnium high-entropy alloy, forming a TaNbHfZr-Cu high-entropy alloy coating, and preparing a TaNbHfZr-Cu current collector. The thickness of the copper foil substrate is 12 μm, and the thickness of the TaNbHfZr-Cu high-entropy alloy coating is 50 nm. The process parameters of magnetron sputtering are as follows: the base vacuum degree is 5.0×10 -4 Pa, the sputtering power is 110 W, the working gas pressure is 0.35 Pa, the working gas is argon, the target distance is 40 cm, and the sputtering temperature is 25℃.

[0076] S3, preparation of Li-TaNbHfZr-Cu with ultra-thin metal lithium negative electrode high-entropy current collector integrated structure

[0077] An ultra-thin metal lithium negative electrode is deposited on the surface of the above-mentioned TaNbHfZr-Cu current collector by magnetron sputtering technology. The sample roller speed is set to 5 rpm. The process parameters of magnetron sputtering are as follows: the base vacuum degree is 5.0×10 -4 Pa, the sputtering power is 70 W, the working gas pressure is 0.35 Pa, the working gas is argon, the target distance is 40 cm, and the sputtering temperature is 25℃. The thickness of the deposited metal lithium is 30 μm. The Li-TaNbHfZr-Cu current collector with ultra-thin metal lithium negative electrode is punched to the required shape for subsequent NCM811 full battery assembly needs.

[0078] S4, preparation of NCM811-Al positive electrode

[0079] The NCM811 positive electrode material powder, Super-P and polyvinylidene fluoride are dispersed in N-methyl pyrrolidone at a mass ratio of 90:5:5 by vacuum stirring to form an NCM811 slurry with a viscosity of 5 Pa·s. The above-mentioned positive electrode slurry is blade-coated onto the surface of an aluminum foil, vacuum dried at a temperature of 100℃ for 2 hours, and then rolled and punched to the required shape to prepare an Al-NCM811 positive electrode sheet. The prepared positive electrode has a surface loading of 5 mAh / cm 2 .

[0080] S5, preparation of electrolyte

[0081] Equal volumes of dimethyl carbonate and diethyl carbonate are mixed, and lithium hexafluorophosphate is dispersed in the mixed solution to prepare an electrolyte solution with a lithium hexafluorophosphate concentration of 1 mol / L.

[0082] S6, Al-NCM811|Li-TaNbHfZr-Cu battery cell assembly with high specific energy

[0083] Ten pieces of the ultra-thin metal lithium negative electrode high-entropy current collector integrated structure Li-TaNbHfZr-Cu prepared in S3, and eleven pieces of the positive electrode NCM811-Al prepared in S4 and a polyethylene separator were prepared into a high specific energy lithium battery cell by stacking. Then the cell was placed in a pre-punched aluminum plastic bag. After drying at 100°C for 20h, the electrolyte prepared in S5 was injected, and the amount of electrolyte added was 3g / Ah. Then the prepared Al-NCM811|Li-TaNbHfZr-Cu battery cell was subjected to formation treatment, and the formation process was as follows: constant current and constant voltage charging at a rate of 0.1C to 4.3V, and constant current discharging at a rate of 0.1C to 3.0V. After the formation treatment, the cell was exhausted and sealed, labeled and stored.

[0084] It was found through charge-discharge comparison test of the original copper foil and the ultra-thin metal lithium negative electrode high-entropy current collector integrated structure prepared in Example 2 that after sputtering the TaNbHfZr high-entropy alloy coating of the application on the current collector, the nucleation potential barrier of lithium was reduced, thereby being able to control the deposition of lithium in space, so that lithium was uniformly deposited on the current collector with the TaNbHfZr high-entropy alloy coating attached. This function prevents the free growth of lithium dendrites, thereby avoiding the safety hazards such as internal short circuit of the battery caused by the contact of dendrites with the positive electrode. The charge-discharge cycle performance of the metal lithium negative electrode is obviously improved, which is specifically manifested in that as the number of cycles increases, the capacity of the battery remains stable, and the coulombic efficiency remains at a high level after 200 cycles.

[0085] Example 3

[0086] Preparation of ultra-thin metal lithium negative electrode zirconium tantalum niobium titanium tungsten high-entropy current collector (Li-ZrTaNbTiW-Cu) and application thereof in NCM811 full battery

[0087] S1, preparation of ZrTaNbTiW high-entropy alloy target

[0088] Nb, Zr, Ta, Ti and W metal powders with a purity of 99.99% were dispersed in acetone according to a mass ratio of 1:1:1:1:1, and mixed by using a planetary ball mill. Then the dried mixed metal powder was pressed into the required size of the sputtering target, and then sintered into a ZrTaNbTiW high-entropy alloy target for sputtering by using flash sintering. The purity of the target was ≥99.99%.

[0089] S2, preparation of ZrTaNbTiW-Cu high-entropy current collector

[0090] The pre-purchased copper foil is mounted on the sample roller, and the pre-prepared zirconium tantalum niobium titanium tungsten high-entropy alloy target material is cleaned with acetone and then dried after baking, and then mounted on the magnetron sputtering cathode, and pre-sputtered for 5 min to remove the surface oxides and other impurities of the target material. Open the sample roller and the receiving roller, set the speed to 5 rpm, open the niobium molybdenum tantalum hafnium high-entropy alloy target cathode power to start sputtering niobium molybdenum tantalum hafnium high-entropy alloy, and form a ZrTaNbTiW-Cu high-entropy alloy coating to prepare a ZrTaNbTiW-Cu current collector. The thickness of the copper foil substrate is 12 μm, the thickness of the ZrTaNbTiW-Cu high-entropy alloy coating is 50 nm, and the process parameters of magnetron sputtering are: base vacuum degree is 5.0×10 -4 Pa, sputtering power is 110 W, working gas pressure is 0.35 Pa, working gas is argon, target distance is 40 cm, and sputtering temperature is 25℃.

[0091] S3, preparation of Li-ZrTaNbTiW-Cu with ultra-thin metal lithium negative electrode high-entropy current collector integrated structure

[0092] An ultra-thin metal lithium negative electrode is deposited on the surface of the above-mentioned ZrTaNbTiW-Cu current collector by magnetron sputtering technology, and the sample roller speed is set to 5 rpm. The process parameters of magnetron sputtering are: base vacuum degree is 5.0×10 -4 Pa, sputtering power is 70 W, working gas pressure is 0.35 Pa, working gas is argon, target distance is 40 cm, and sputtering temperature is 25℃. The thickness of the deposited metal lithium is 30 μm. The Li-ZrTaNbTiW-Cu current collector loaded with the ultra-thin metal lithium negative electrode is punched to the required shape for subsequent NCM811 full battery assembly needs.

[0093] S4, preparation of NCM811-Al positive electrode

[0094] The NCM811 positive electrode material powder, Super-P and polyvinylidene fluoride are dispersed in N-methyl pyrrolidone in a mass ratio of 90:5:5 by vacuum stirring to form an NCM811 slurry with a viscosity of 5 Pa·s. The above positive electrode slurry is blade-coated onto the surface of an aluminum foil, vacuum dried at a temperature of 100℃ for 2h, then rolled and punched to the required shape to prepare an Al-NCM811 positive electrode sheet. The prepared positive electrode surface loading is 5 mAh / cm 2 .

[0095] S5, preparation of electrolyte

[0096] Equal volumes of dimethyl carbonate and diethyl carbonate are mixed, and lithium hexafluorophosphate is dispersed in the mixed solution to prepare an electrolyte solution with a lithium hexafluorophosphate concentration of 1 mol / L.

[0097] S6, Al-NCM811|Li-ZrTaNbTiW-Cu battery cell assembly with high specific energy

[0098] Ten pieces of the ultra-thin metal lithium negative electrode high-entropy current collector integrated structure Li-ZrTaNbTiW-Cu prepared in S3, eleven pieces of the positive electrode NCM811-Al prepared in S4 and a polyethylene separator were stacked to prepare a high specific energy lithium battery cell, and then the cell was placed in a pre-stamped aluminum plastic bag. After drying at 100°C for 20h, the electrolyte prepared in S5 was injected, and the amount of electrolyte added was 3g / Ah. Then the prepared Al-NCM811|Li-ZrTaNbTiW-Cu battery cell was subjected to formation treatment, and the formation process was as follows: constant current and constant voltage charging at a rate of 0.1C to 4.3V, and constant current discharging at a rate of 0.1C to 3.0V. After the formation treatment, the cell was exhausted and sealed, labeled and stored.

[0099] It was found through charge and discharge comparison tests of the original copper foil and the ultra-thin metal lithium negative electrode high-entropy current collector integrated structure prepared in Example 3 that when the ZrTaNbTiW high-entropy alloy coating of the application was sputtered on the current collector, the nucleation potential barrier of lithium was reduced, thereby enabling spatial control of lithium deposition, allowing lithium to be uniformly deposited on the current collector with the ZrTaNbTiW high-entropy alloy coating attached. This function prevents the free growth of lithium dendrites, thereby avoiding safety hazards such as internal short circuits caused by dendrite contact with the positive electrode. The charge and discharge cycle performance of the metal lithium negative electrode was significantly improved, specifically in that as the number of cycles increased, the capacity of the battery remained stable, and the coulombic efficiency remained at a high level after 200 cycles.

[0100] Example 4

[0101] Preparation of ultra-thin metal lithium negative electrode hafnium niobium titanium vanadium zirconium nitride high-entropy current collector (Li-(HfNbTiVZr)N-Cu) and application thereof in NCM811 full battery

[0102] S1, HfNbTiVZr high-entropy alloy target preparation

[0103] Nb, Hf, Ti, Ti, and V metal powders with a purity of 99.99% were dispersed in acetone according to a mass ratio of 1:1:1:1:1, and mixed using a planetary ball mill. Then, the dried mixed metal powder was pressed into the desired size of the sputtering target, and a flash sintering method was used to sinter the HfNbTiVZr high-entropy alloy target for sputtering. The purity of the target was ≥99.99%.

[0104] S2, (HfNbTiVZr)N-Cu high-entropy current collector preparation

[0105] The pre-purchased copper foil is mounted on the sample roller. The pre-prepared hafnium-niobium-titanium-vanadium-zirconium high-entropy alloy target is cleaned with acetone and dried, and then mounted on the magnetron sputtering cathode. The target is pre-sputtered for 5 min to remove the surface oxides and other impurities. The sample feeding roller and the sample collecting roller are opened, and the speed is set to 5 rpm. The niobium-molybdenum-tantalum-hafnium high-entropy alloy target cathode power is turned on to start sputtering the niobium-molybdenum-tantalum-hafnium high-entropy alloy, forming a (HfNbTiVZr)N-Cu high-entropy alloy coating, and preparing a (HfNbTiVZr)N-Cu current collector. The thickness of the copper foil substrate is 12 μm, and the thickness of the (HfNbTiVZr)N-Cu high-entropy alloy coating is 50 nm. The process parameters of magnetron sputtering are as follows: the base vacuum degree is 5.0×10 -4 Pa, the sputtering power is 100 W, the working gas pressure is 0.35 Pa, the working gas is nitrogen, the target distance is 40 cm, and the sputtering temperature is 25℃.

[0106] S3, preparation of Li-(HfNbTiVZr)N-Cu with ultra-thin metal lithium negative electrode high-entropy current collector integrated structure

[0107] An ultra-thin metal lithium negative electrode is deposited on the surface of the (HfNbTiVZr)N-Cu current collector by magnetron sputtering technology. The sample roller speed is set to 5 rpm. The process parameters of magnetron sputtering are as follows: the base vacuum degree is 5.0×10 -4 Pa, the sputtering power is 70 W, the working gas pressure is 0.35 Pa, the working gas is argon, the target distance is 40 cm, and the sputtering temperature is 25℃. The thickness of the deposited metal lithium is 30 μm. The Li-(HfNbTiVZr)N-Cu current collector with ultra-thin metal lithium negative electrode is punched to the required shape for subsequent NCM811 full battery assembly needs.

[0108] S4, preparation of NCM811-Al positive electrode

[0109] The NCM811 positive electrode material powder, Super-P and polyvinylidene fluoride are dispersed in N-methyl pyrrolidone at a mass ratio of 90:5:5 by vacuum stirring to form an NCM811 slurry with a viscosity of 5 Pa·s. The above positive electrode slurry is blade-coated onto the surface of an aluminum foil, vacuum dried at a temperature of 100℃ for 2 h, and then rolled and punched to the required shape to prepare an Al-NCM811 positive electrode sheet. The prepared positive electrode surface loading is 5 mAh / cm 2 .

[0110] S5, preparation of electrolyte

[0111] Equal volumes of dimethyl carbonate and diethyl carbonate are mixed, and lithium hexafluorophosphate is dispersed in the mixed solution to prepare an electrolyte solution with a lithium hexafluorophosphate concentration of 1 mol / L.

[0112] S6, high specific energy lithium battery Al-NCM811|Li-(HfNbTiVZr)N-Cu cell assembly

[0113] Ten pieces of the ultra-thin metal lithium negative electrode high-entropy current collector integrated structure Li-(HfNbTiVZr)N-Cu prepared in S3, eleven pieces of the positive electrode NCM811-Al prepared in S4 and a polyethylene separator were prepared into a high specific energy lithium battery cell by means of lamination, and then the cell was placed in a pre-punched aluminum plastic bag. After drying at 100 DEG C for 20 hours, the electrolyte prepared in S5 was injected, and the amount of electrolyte added was 3 g / Ah. Then the prepared Al-NCM811|Li-(HfNbTiVZr)N-Cu cell was subjected to formation treatment, and the formation process was as follows: constant current and constant voltage charging at a rate of 0.1C to 4.3 V, and constant current discharging at a rate of 0.1C to 3.0 V. After the formation treatment, the cell was exhausted and finally sealed, labeled and stored.

[0114] It was found by charge-discharge comparison test of the original copper foil and the ultra-thin metal lithium negative electrode high-entropy current collector integrated structure prepared in Example 4 that after the (HfNbTiVZr)N high-entropy nitride coating of the application was sputtered on the current collector, the nucleation potential barrier of lithium was reduced, thereby the deposition of lithium in space could be controlled, and lithium was uniformly deposited on the current collector with the attached (HfNbTiVZr)N high-entropy nitride coating. This function prevented the free growth of lithium dendrites, thereby avoiding the safety hazards such as internal short circuit of the battery caused by the contact of dendrites with the positive electrode. The charge-discharge cycle performance of the metal lithium negative electrode was obviously improved, which was specifically manifested in that the capacity of the battery remained stable with the increase of the cycle number, and the coulombic efficiency remained at a high level after 200 cycles.

[0115] The coulombic efficiency of the NCM811 full battery prepared by Examples 1-4 of the application was tested, and the results are shown in Table 1.

[0116] Table 1: Deposition and stripping coulombic efficiency of metal lithium negative electrode on the surface of high-entropy current collector and capacity retention rate of full battery

[0117]

[0118] As shown in Table 1, the deposition and stripping coulombic efficiency of metal lithium on the surface of the high-entropy current collector in Examples 1-4 of the application was higher than 97%, and the NCM811 lithium battery using the ultra-thin metal lithium high-entropy current collector integrated structure of the application all showed excellent cycle stability, and could still show a capacity retention rate higher than 85% after 500 cycles.

[0119] Figure 1The deposition and stripping Coulombic efficiency of metallic lithium on the surface of the high-entropy current collector of Example 1 of the present application was measured. As shown in Table 2, the deposition and stripping Coulombic efficiency of metallic lithium on the surface of the NbMoTaHf-Cu high-entropy current collector was 97.61%, and remained stable over 200 cycles. This demonstrates that the high-entropy surface designed in the present application does significantly improve the cycling stability of metallic lithium, compared to the lower Coulombic efficiency and unstable cycling of metallic lithium on the surface of the original copper foil. Figure 1

[0120] It should be noted that when numerical ranges are used herein, it is intended to include every number within the range and any number that falls within the range. As a result, every numerical range disclosed herein is intended to include every number within the range and any number that falls within the range. The preferred embodiments of the present application have been described herein. Obviously, modifications and alterations will occur to others upon reading and understanding the preceding detailed description. It is intended that the application be construed as including all such modifications and alterations and that it be limited only by the scope of the following claims, including any equivalents thereof.

[0121] Obviously, numerous modifications and variations of the present application are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims and their equivalents, the application can be practiced otherwise than as specifically described herein.​

Claims

1. A method for preparing a high-entropy current collector of metal lithium negative electrode, characterized in that, The method comprises the following steps: The high-entropy alloy target material is sputtered on the current collector substrate by a first magnetron sputtering method to form a high-entropy alloy oxide coating or a high-entropy alloy nitride coating; The metal lithium target material is sputtered on the surface of the high-entropy alloy oxide coating or the high-entropy alloy nitride coating by a second magnetron sputtering method to deposit a metal lithium film layer, i.e. a metal lithium negative electrode high-entropy current collector is obtained; The high-entropy elements in the high-entropy alloy oxide coating or the high-entropy alloy nitride coating are three or more of scandium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, yttrium, zirconium, niobium, molybdenum, technetium, ruthenium, rhodium, hafnium, tantalum, tungsten, rhenium, lanthanum, cerium, praseodymium, neodymium, promethium, samarium, and the atomic percentage of each high-entropy element is equal in the high-entropy alloy oxide coating or the high-entropy alloy nitride coating, and the sum of the atomic percentages of the high-entropy elements is 100%.

2. The method of claim 1, wherein the metal lithium negative electrode high-entropy current collector is prepared by the steps of: In the process of sputtering the high-entropy alloy target material on the current collector substrate, the gas for magnetron sputtering is oxygen or nitrogen, and the gas pressure is 0.25 Pa to 0.35 Pa; when the gas for magnetron sputtering is oxygen, a high-entropy alloy oxide coating is obtained; and when the gas for magnetron sputtering is nitrogen, a high-entropy alloy nitride coating is obtained; In the process of sputtering the metal lithium target material on the surface of the high-entropy alloy oxide coating or the high-entropy alloy nitride coating, the gas for magnetron sputtering is argon, and the gas pressure is 0.25 Pa to 0.35 Pa.

3. The method of claim 1, wherein the metal lithium negative electrode high-entropy current collector is prepared by the steps of: The current collector substrate is a copper foil or an aluminum-copper composite substrate.

4. The method of claim 1, wherein the metal lithium negative electrode high-entropy current collector is prepared by the steps of: The method comprises the following steps: The raw materials of the high-entropy elements are mixed in an atomic ratio, ball-milled, and then burned by a flash method to form the high-entropy alloy target material, and the purity of the high-entropy alloy target material is greater than or equal to 99.99%; The high-entropy alloy target material is sputtered on the current collector substrate by a winding direct-current magnetron reaction sputtering method to form a high-entropy alloy oxide coating or a high-entropy alloy nitride coating, and then the metal lithium target material is sputtered on the surface of the high-entropy alloy oxide coating or the high-entropy alloy nitride coating by the winding direct-current magnetron reaction sputtering method to deposit a metal lithium film layer, i.e. a metal lithium negative electrode high-entropy current collector is obtained; In the process of DC magnetron sputtering, the vacuum degree of magnetron sputtering is 9.9×10 -5 Pa~50×10 -5 Pa, the target distance is 20 cm~50 cm, the sputtering temperature is 20℃~30℃, and the unwinding and winding speeds of the roll are 5 rpm~10 rpm.

5. The metal lithium negative electrode high-entropy current collector prepared by the method of any one of claims 1-4, characterized in that, In the high-entropy current collector, the thickness of the high-entropy alloy oxide coating or the high-entropy alloy nitride coating is 20 nm to 200 nm, and the thickness of the metal lithium film layer is 5 μm to 30 μm.

6. Use of the metal lithium negative electrode high-entropy current collector of claim 5 in a lithium battery, characterized in that, The lithium battery comprises a positive electrode, a separator, a metal lithium negative electrode high-entropy current collector, and an electrolyte, the positive electrode is one of lithium cobaltate, nickel-manganese-cobaltate, nickel-aluminum-cobaltate, and lithium-rich manganese-based material, the separator is a polyethylene separator or a polypropylene separator, and the electrolyte is a mixed solution of lithium hexafluorophosphate, dimethyl carbonate, and diethyl carbonate.

7. Use according to claim 6, characterized in that, The preparation process of the positive electrode includes the following steps: stirring and dispersing the positive electrode material, the Super-P conductive agent and the polyvinylidene fluoride in a solvent at a mass ratio of 90:5:5 to form a positive electrode slurry with a viscosity of 1 Pa·s~10 Pa·s, scraping the positive electrode slurry to the surface of an aluminum foil substrate, and roll pressing after drying to prepare a positive electrode sheet. The prepared positive electrode has a surface loading of 1 mAh / cm 2 ~5 mAh / cm 2 .

8. Use according to claim 6, characterized in that, The concentration of lithium hexafluorophosphate in the electrolyte is 1 mol / L to 5 mol / L, and the volume ratio of dimethyl carbonate to diethyl carbonate is 1:1.

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