A method for preparing NiZnInCuCd nano-ultrathin high entropy alloy layer

Abstract

The present invention discloses a method for preparing a NiZnInCuCd nano-ultrathin high entropy alloy layer, comprising the following steps: S1, weighing nickel, zinc, cadmium, indium and copper sources in equal molar ratios, placing them in a mortar and grinding for 1 hour, dissolving the powder in 5-10 mL of anhydrous ethanol, and ultrasonically dispersing the powder, stirring for 1-3 hours to obtain a multi-metal ion solution. S2, activating carbon paper in a plasma cleaning machine and cutting it into 0.785 cm 2 The multi-metal ion precursor solution is absorbed and dropped on the disc, and then vacuum dried in an oven at 50-80°C for 8-24h to obtain a precursor. S3. The precursor is placed in a tubular atmosphere furnace chamber filled with a mixed atmosphere. In the first stage, the furnace chamber temperature is set to 200-500°C and sintered for 1-2h; in the second stage, the furnace chamber temperature is set to 500-900°C and sintered for 30-60min; in the third stage, the furnace chamber temperature is set to 900-1100°C and sintered for 10-30min. The heating rate of the above stages is 5-10°C / s; a high entropy alloy composite material (NiZnInCuCd HEA / C) with a three-dimensional framework carbon fiber as the main body and loaded with NiZnInCuCd nanoparticles is obtained by gradient sintering.

Description

Technical Field

[0001] The invention belongs to the technical field of functional materials, and in particular relates to a method for preparing a NiZnInCuCd nanometer ultra-thin high-entropy alloy layer. Background Art

[0002] Lithium metal anodes, owing to their high energy density and low electrochemical potential, have become the mainstay of the new energy electrification era. However, due to the high reactivity of lithium metal, lithium metal anodes face challenges such as uncontrolled dendrite growth and degraded Coulombic efficiency. To address these issues, researchers have proposed numerous modification strategies. Among these, the use of three-dimensional carbon frameworks as lithium supports is considered an effective approach to achieving dendrite-free lithium metal batteries. However, the low lithium affinity of carbon-based surfaces presents a significant barrier to initial lithium nucleation, making it difficult to optimize the electrochemical performance of lithium metal batteries. In recent years, efforts have focused on modulating the surface lithium affinity of carbon materials by doping them with precious metal nanoparticles, heteroatom functional groups, and other traditional alloy materials. While these strategies can suppress dendritic lithium growth, few studies have explored synergistic structural design and interface engineering. Therefore, constructing three-dimensional carbon-based structures encapsulated by ultrathin high-entropy alloy layers loaded with lithium-philic nanoparticles to guide uniform lithium nucleation is becoming increasingly important for the development of lithium metal anodes.

[0003] High entropy alloys can achieve the advantages of high activity, high selectivity, stability and low cost through multi-component design and element regulation. Therefore, they are widely used in the fields of catalysis and energy and have broad application prospects. The complex lattice structure will produce obvious lattice distortion, resulting in the generation of a large number of dislocations and defects. At the same time, it can provide new and adjustable active sites in multiple adjacent elements, and the interaction can be regulated by rationally selecting the configuration and composition of the elements. These characteristics lead to some unique properties, such as multiple lithium ions (Li + ) transport pathways, reactive sites, and high ionic conductivity. Compared with conventional alloys, this potential lithiophilic property can be modulated by the synergistic action of multiple elements in high entropy alloys to increase adsorption and diffusion energy. Therefore, it is necessary to further study the lithiophilicity of high entropy alloys (HEAs) in lithium metal anodes and understand the role of HEAs in Li + The role played in the dynamic transmission process. Summary of the Invention

[0004] The purpose of the present invention is to solve the above problems and provide a method for preparing a NiZnInCuCd nano-ultrathin high-entropy alloy layer with excellent electrochemical performance for lithium metal batteries by providing a cocktail effect produced by the synergy of different constituent elements in a high-entropy alloy, so that the lithium ions on the negative electrode surface have multiple transmission paths and abundant deposition sites.

[0005] To solve the above technical problems, the technical solution of the present invention is: a method for preparing a NiZnInCuCd nano-ultrathin high entropy alloy layer, comprising the following steps:

[0006] S1. Weigh nickel, zinc, cadmium, indium, and copper sources in equal molar ratios and grind them in a mortar for 1 hour. Dissolve the powder in 5-10 mL of anhydrous ethanol and disperse it ultrasonically. Stir for 1-3 hours to obtain a multi-metal ion solution.

[0007] S2, carbon paper activated in a plasma cleaning machine and cut into 0.785cm 2 The multi-metal ion precursor solution is absorbed and dropped onto the disc, and then vacuum-dried in an oven at 50-80° C. for 8-24 h to obtain a precursor;

[0008] S3. Place the precursor in a tubular atmosphere furnace chamber filled with a mixed atmosphere. In the first stage, set the furnace chamber temperature to 200-500°C and sinter for 1-2 hours; in the second stage, set the furnace chamber temperature to 500-900°C and sinter for 30-60 minutes; in the third stage, set the furnace chamber temperature to 900-1100°C and sinter for 10-30 minutes. The heating rate in the above stages is 5-10°C / s. A high-entropy alloy composite material (NiZnInCuCd HEA / C) with a three-dimensional framework carbon fiber as the main body and loaded with NiZnInCuCd nanoparticles is obtained by gradient sintering.

[0009] Furthermore, the nickel, zinc, cadmium, indium and copper sources in step S1 are any one of their sulfates, chlorides and nitrates.

[0010] Furthermore, the ultrasonic dispersion time in step S1 is 1 to 10 hours.

[0011] Furthermore, in step S2, the activation treatment time of the carbon paper in the plasma surface treatment machine is 5 to 30 minutes.

[0012] Furthermore, the amount of carbon paper added each time in step S2 is 5 to 100 μL / cm 2 .

[0013] Furthermore, in the atmosphere furnace in step S3, the atmosphere is a gas combination (Ar2:H2=9:1).

[0014] The beneficial effects of the present invention are as follows: the present invention provides a method for preparing a NiZnInCuCd nano-ultra-thin high-entropy alloy layer, which obtains an ultra-thin high-entropy alloy layer loaded with nanoparticles by gradient sintering. This cocktail effect of different constituent elements enables lithium ions to have multiple transport pathways and abundant active sites, providing a low barrier for uniform lithium nucleation, and making the battery have excellent electrochemical performance. In a symmetrical battery, the Li@HEA / C negative electrode cycles for more than 1000 hours at 40mAcm-2 / 40mAh cm-2. In addition, the Li@HEA / C||LFP battery significantly improves the battery's capacity retention and exhibits excellent high coulombic efficiency after 120 cycles at 0.1C. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is an XRD pattern of an ultrathin high entropy alloy layer loaded with NiZnInCuCd nanoparticles prepared in Example 1 of a method for preparing an ultrathin high entropy alloy layer of NiZnInCuCd nanoparticles of the present invention;

[0016] Figure 2 This is a SEM image of an ultra-thin high-entropy alloy layer loaded with NiZnInCuCd nanoparticles prepared in Example 1 of the present invention;

[0017] Figure 3 This is an EDS image of an ultra-thin high-entropy alloy layer loaded with NiZnInCuCd nanoparticles prepared in Example 1 of the present invention;

[0018] Figure 4 The symmetrical battery prepared in Example 1 of the present invention with a loaded NiZnInCuCd nanoparticle ultrathin high entropy alloy layer is -2 , 40mAh·cm -2 Cycle performance diagram;

[0019] Figure 5 This is an overpotential diagram of an ultrathin high entropy alloy layer loaded with NiZnInCuCd nanoparticles prepared in Example 1 of the present invention;

[0020] Figure 6 This is a rate performance diagram of a symmetrical battery of a high-entropy alloy NiZnInCuCd / C composite material prepared in Example 1 of the present invention;

[0021] Figure 7 This is a full-cell performance diagram of the high-entropy alloy NiZnInCuCd / C composite material prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0022] The present invention will be further described below with reference to the accompanying drawings and specific embodiments:

[0023] Example 1

[0024] like Figures 1 to 7 As shown, the present invention provides a method for preparing a NiZnInCuCd nano-ultra-thin high entropy alloy layer, comprising the following steps:

[0025] S1. Weigh nickel, zinc, cadmium, indium and copper sources in equal molar ratios and grind them in a mortar for 1 hour. Dissolve the powder in 5-10 mL of anhydrous ethanol and disperse it by ultrasonication. Stir for 1-3 hours to obtain a multi-metal ion solution.

[0026] In step S1, the nickel, zinc, cadmium, indium and copper sources are any one of their sulfates, chlorides and nitrates. The ultrasonic dispersion time in step S1 is 1 to 10 hours.

[0027] In actual use, step S1 specifically involves weighing 0.01 mmol of Ni(NO3)2·6H2O, Cu(NO3)2·9H2O, Zn(NO3)2·6H2O, Cd(NO3)2·4H2O, and In(NO3)3 in an equimolar amount and placing them in a mortar for 1 hour to refine them, dissolving them in 5 mL of anhydrous ethanol and ultrasonically dispersing them for 2 hours, and stirring them for 1 hour to obtain a multi-metal ion solution.

[0028] S2, carbon paper activated in a plasma cleaning machine and cut into 0.785cm 2 The multi-metal ion precursor solution is absorbed and dropped on the disc, and then vacuum-dried in an oven at 50-80° C. for 8-24 h to obtain a precursor.

[0029] In step S2, the activation treatment time of the carbon paper in the plasma surface treatment machine is 5 to 30 minutes. The amount of carbon paper added each time in step S2 is 5 to 100 μL / cm 2 .

[0030] In actual use, step S2, the carbon paper is placed in a plasma treatment machine and processed for 15 minutes and then cut into 0.785 cm 2 In addition, the high entropy precursor solution was evenly absorbed and dropped at 20 μL / cm 2 The precursor was prepared by placing the precursor on carbon paper and then drying it in a vacuum oven at 60°C for 24 hours to obtain a NiZnInCuCd / C precursor.

[0031] S3. Place the precursor in a tubular atmosphere furnace chamber filled with a mixed atmosphere. In the first stage, set the furnace chamber temperature to 200-500°C and sinter for 1-2 hours; in the second stage, set the furnace chamber temperature to 500-900°C and sinter for 30-60 minutes; in the third stage, set the furnace chamber temperature to 900-1100°C and sinter for 10-30 minutes. The heating rate in the above stages is 5-10°C / s. A high-entropy alloy composite material (NiZnInCuCd HEA / C) with a three-dimensional framework carbon fiber as the main body and loaded with NiZnInCuCd nanoparticles is obtained by gradient sintering.

[0032] In the atmosphere furnace in step S3, the atmosphere is a gas combination (Ar2:H2=9:1).

[0033] In actual use, step S3 places the precursor in a tubular atmosphere furnace chamber filled with a mixed atmosphere. In the first stage, the chamber temperature is set at 500°C for 1 hour; in the second stage, the chamber temperature is set at 900°C for 30 minutes; and in the third stage, the chamber temperature is set at 1100°C for 10 minutes. The heating rate for each stage is 10°C / s. A high-entropy alloy composite (NiZnInCuCdHEA / C) with a three-dimensional framework carbon fiber as the main body and loaded with NiZnInCuCd nanoparticles is obtained through gradient sintering.

[0034] The morphology, composition, and electrochemical properties of an ultra-thin high-entropy alloy layer loaded with NiZnInCuCd nanoparticles prepared in this example were measured, and the results are as follows:

[0035] 1. Composition

[0036] like Figure 1 As shown in the figure, the XRD diffraction peaks of a synthesized ultra-thin high entropy alloy layer loaded with NiZnInCuCd nanoparticles, the three diffraction peaks at diffraction angles of 43°, 50° and 74° correspond to the (111), (200) and (220) planes of the FCC phase, respectively.

[0037] 2. Appearance

[0038] like Figure 2 As shown, it can be seen that the microscopic morphology of an ultra-thin high entropy alloy layer loaded with NiZnInCuCd nanoparticles is that the high entropy alloy nanoparticles thinly cover the entire carbon fiber surface, forming an ultra-thin high entropy alloy layer (20 nm).

[0039] like Figure 3 As shown in the figure, in order to increase the conductivity of the cross section and better observe the distribution of elements, a 500nm thick Pt metal was deposited on the cross section. The energy dispersive spectroscopy (EDS) mapping image shows that the NiZnInCuCd HEA is evenly distributed on the carbon fiber.

[0040] 3. Electrochemical performance

[0041] like Figure 4 As shown in the figure, the ultra-thin high entropy alloy layer material loaded with NiZnInCuCd nanoparticles prepared in Example 1 was prepared into a battery negative electrode. -2 , with a specific capacity of 40 mAh cm -2 Under the condition of , the battery has stable overpotential and cycle performance.

[0042] like Figure 5 As shown in the figure, lithium foil was assembled with blank carbon paper, blank copper foil and the present material into half-cells at a current density of 0.5 mA cm -2 The test was carried out under the conditions of 100 nm and 200 nm, and it was found that the overpotential of the battery was compared with that of the lithium-copper half-cell and the lithium-carbon half-cell: the battery negative electrode prepared by the ultra-thin high-entropy alloy layer material loaded with NiZnInCuCd nanoparticles had an ultra-low overpotential (2.6 mV), showing excellent lithium affinity and excellent lithium battery negative electrode potential.

[0043] like Figure 6 As shown, it was assembled into paired cells and tested at 1, 2, 5, 10, 20, 40 and 60 mA cm -2 The battery rate test was carried out at a current density of 60 mA cm to further study the rate performance of the HEA / C@Li anode. The negative electrode battery achieved excellent cycle stability even at a high current density of 60 mA cm -2 It can work stably even under harsh conditions.

[0044] like Figure 7 As shown, when it is matched with a lithium iron phosphate positive electrode as a full battery; at a current density of 0.1C, the battery capacity retention is significantly improved after 120 cycles and an excellent high coulombic efficiency is exhibited.

[0045] Example 2

[0046] The present embodiment differs from the first embodiment in the following aspects: This embodiment provides a method for preparing a NiZnInCuCd nano-ultrathin high entropy alloy layer, which specifically includes the following steps:

[0047] S1. Weigh 0.05 mmol of Ni(NO3)2·6H2O, Cu(NO3)2·9H2O, Zn(NO3)2·6H2O, Cd(NO3)2·4H2O, and In(NO3)3 in an equimolar ratio of 0.05 mmol / L and place them in a mortar for 1 hour to refine them. Dissolve them in 10 mL of anhydrous ethanol and ultrasonically disperse them for 2 hours. Stir for 2 hours to obtain a multi-metal ion solution.

[0048] S2, place the carbon paper into the plasma treatment machine for 10 minutes and then cut into 0.785cm2 In addition, the high entropy precursor solution was evenly absorbed and dropped at 50 μL / cm 2 The resulting mixture was deposited on carbon paper and then dried in a vacuum oven at 50° C. for 15 h to obtain a NiZnInCuCd / C precursor.

[0049] S3. The precursor was placed in a tubular atmosphere furnace chamber filled with a mixed atmosphere. In the first stage, the furnace chamber temperature was set at 500°C for 1 hour; in the second stage, the furnace chamber temperature was set at 800°C for 60 minutes; and in the third stage, the furnace chamber temperature was set at 1000°C for 30 minutes. The heating rate in each stage was 5°C / s. A high-entropy alloy composite (NiZnInCuCd HEA / C) with a three-dimensional framework carbon fiber as the main body and loaded with NiZnInCuCd nanoparticles was obtained through gradient sintering.

[0050] Example 3

[0051] The present embodiment differs from the first embodiment in the following aspects: This embodiment provides a method for preparing a NiZnInCuCd nano-ultrathin high entropy alloy layer, which specifically includes the following steps:

[0052] S1. Weigh 0.1 mmol of Ni(NO3)2·6H2O, Cu(NO3)2·9H2O, Zn(NO3)2·6H2O, Cd(NO3)2·4H2O, and In(NO3)3 in an equimolar ratio of 0.1 mmol / L and place them in a mortar for 1 hour to refine them. Dissolve them in 10 mL of anhydrous ethanol and ultrasonically disperse them for 5 hours. Stir for 1 hour to obtain a multi-metal ion solution.

[0053] S2, place the carbon paper into the plasma treatment machine for 5 minutes and then cut into 0.785cm 2 In addition, the high entropy precursor solution was evenly absorbed and dropped at 10 μL / cm 2 The resulting mixture was deposited on carbon paper and then dried in a vacuum oven at 60° C. for 8 h to obtain a NiZnInCuCd / C precursor.

[0054] S3. The precursor was placed in a tubular atmosphere furnace chamber filled with a mixed atmosphere. In the first stage, the furnace chamber temperature was set at 300°C for 1 hour; in the second stage, the furnace chamber temperature was set at 900°C for 50 minutes; and in the third stage, the furnace chamber temperature was set at 1100°C for 10 minutes. The heating rate in all these stages was 5°C / s. A high-entropy alloy composite (NiZnInCuCd HEA / C) composed of a three-dimensional carbon fiber framework and loaded with NiZnInCuCd nanoparticles was obtained through gradient sintering.

[0055] Example 4

[0056] The present embodiment differs from the first embodiment in the following aspects: This embodiment provides a method for preparing a NiZnInCuCd nano-ultrathin high entropy alloy layer, which specifically includes the following steps:

[0057] S1. Weigh 0.15 mmol of Ni(NO3)2·6H2O, Cu(NO3)2·9H2O, Zn(NO3)2·6H2O, Cd(NO3)2·4H2O, and In(NO3)3 in an equimolar ratio and place them in a mortar for 1 hour to refine them. Dissolve them in 5 mL of anhydrous ethanol and ultrasonically disperse them for 3 hours. Stir for 1 hour to obtain a multi-metal ion solution.

[0058] S2, place the carbon paper into the plasma treatment machine for 5 minutes and then cut into 0.785cm 2 In addition, the high entropy precursor solution was evenly absorbed and added at a rate of 5 μL / cm 2 The resulting mixture was deposited on carbon paper and then dried in a vacuum oven at 60° C. for 10 h to obtain a NiZnInCuCd / C precursor.

[0059] S3. The precursor was placed in a tubular atmosphere furnace chamber filled with a mixed atmosphere. In the first stage, the furnace chamber temperature was set at 500°C for 2 hours; in the second stage, the furnace chamber temperature was set at 700°C for 30 minutes; and in the third stage, the furnace chamber temperature was set at 1100°C for 30 minutes. The heating rate in each stage was 10°C / s. A high-entropy alloy composite (NiZnInCuCd HEA / C) with a three-dimensional framework carbon fiber as the main body and loaded with NiZnInCuCd nanoparticles was obtained through gradient sintering.

[0060] Example 5

[0061] The present embodiment differs from the first embodiment in the following aspects: This embodiment provides a method for preparing a NiZnInCuCd nano-ultrathin high entropy alloy layer, which specifically includes the following steps:

[0062] S1. Weigh 0.2 mmol of Ni(NO3)2·6H2O, Cu(NO3)2·9H2O, Zn(NO3)2·6H2O, Cd(NO3)2·4H2O, and In(NO3)3 in an equimolar ratio of 0.2 mmol / L and place them in a mortar for 1 hour to refine them. Dissolve them in 10 mL of anhydrous ethanol and ultrasonically disperse them for 5 hours. Stir for 3 hours to obtain a multi-metal ion solution.

[0063] S2, place the carbon paper into the plasma treatment machine for 30 minutes and then cut into 0.785cm 2 In addition, the high entropy precursor solution was evenly absorbed and added at a rate of 5 μL / cm 2 The resulting mixture was deposited on carbon paper and then dried in a vacuum oven at 60° C. for 8 h to obtain a NiZnInCuCd / C precursor.

[0064] S3. The precursor was placed in a tubular atmosphere furnace chamber filled with a mixed atmosphere. In the first stage, the furnace chamber temperature was set at 200°C for 1 hour; in the second stage, the furnace chamber temperature was set at 900°C for 30 minutes; and in the third stage, the furnace chamber temperature was set at 1000°C for 60 minutes. The heating rate in all these stages was 5°C / s. A high-entropy alloy composite (NiZnInCuCd HEA / C) with a three-dimensional framework carbon fiber as the main body and loaded with NiZnInCuCd nanoparticles was obtained through gradient sintering.

[0065] Example 6

[0066] The present embodiment differs from the first embodiment in the following aspects: This embodiment provides a method for preparing a NiZnInCuCd nano-ultrathin high entropy alloy layer, which specifically includes the following steps:

[0067] S1. Take 0.5 mmol of Ni(NO3)2·6H2O, Cu(NO3)2·9H2O, Zn(NO3)2·6H2O, Cd(NO3)2·4H2O, and In(NO3)3 in an equimolar ratio of 0.5 mmol / L and place them in a mortar for 1 hour to refine them, and dissolve them in 10 mL of anhydrous ethanol and ultrasonically disperse them for 7 hours. After stirring for 1 hour, a multi-metal ion solution is obtained.

[0068] S2, place the carbon paper into the plasma treatment machine for 15 minutes and then cut into 0.785cm 2 In addition, the high entropy precursor solution was evenly absorbed and dropped at 100 μL / cm 2 The precursor was prepared by placing the precursor on carbon paper and then drying it in a vacuum oven at 60°C for 24 hours to obtain a NiZnInCuCd / C precursor.

[0069] S3. The precursor was placed in a tubular atmosphere furnace chamber filled with a mixed atmosphere. In the first stage, the furnace chamber temperature was set at 400°C for 2 hours; in the second stage, the furnace chamber temperature was set at 800°C for 60 minutes; and in the third stage, the furnace chamber temperature was set at 1100°C for 30 minutes. The heating rate in all these stages was 5°C / s. A high-entropy alloy composite (NiZnInCuCd HEA / C) with a three-dimensional framework carbon fiber as the main body and loaded with NiZnInCuCd nanoparticles was obtained through gradient sintering.

[0070] Example 7

[0071] The present embodiment differs from the first embodiment in the following aspects: This embodiment provides a method for preparing a NiZnInCuCd nano-ultrathin high entropy alloy layer, which specifically includes the following steps:

[0072] S1. Weigh 1 mmol of Ni(NO3)2·6H2O, Cu(NO3)2·9H2O, Zn(NO3)2·6H2O, Cd(NO3)2·4H2O, and In(NO3)3 and place them in a mortar for 1 hour to refine them. Then dissolve them in 10 mL of anhydrous ethanol and ultrasonically disperse them for 10 hours. After stirring for 2 hours, a multi-metal ion solution is obtained.

[0073] S2, place the carbon paper into the plasma treatment machine for 15 minutes and then cut into 0.785cm 2 In addition, the high entropy precursor solution was evenly absorbed and dropped at 50 μL / cm 2 The resulting mixture was deposited on carbon paper and then dried in a vacuum oven at 80°C for 12 hours to obtain a NiZnInCuCd / C precursor.

[0074] S3. The precursor was placed in a tubular atmosphere furnace chamber filled with a mixed atmosphere. In the first stage, the furnace chamber temperature was set at 200°C for 2 hours; in the second stage, the furnace chamber temperature was set at 900°C for 30 minutes; and in the third stage, the furnace chamber temperature was set at 1000°C for 10 minutes. The heating rate in all these stages was 10°C / s. A high-entropy alloy composite (NiZnInCuCd HEA / C) composed of a three-dimensional carbon fiber framework and loaded with NiZnInCuCd nanoparticles was obtained through gradient sintering.

[0075] In the present invention, the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them. In addition to the several methods listed in the embodiments, the selection of nickel salts, copper salts, zinc salts, indium salts and cadmium salts can also be other combinations. The adjustment of the annealing temperature and heating time of the redox reaction and the push-pull method can also be other combinations in addition to the several methods listed in the embodiments.

[0076] Those skilled in the art will appreciate that the embodiments described herein are intended to help readers understand the principles of the present invention, and it should be understood that the scope of protection of the present invention is not limited to such specific descriptions and embodiments. Those skilled in the art can make various other specific variations and combinations based on the technical teachings disclosed in the present invention without departing from the essence of the present invention, and such variations and combinations are still within the scope of protection of the present invention.

Claims

1. A method for preparing a NiZnInCuCd nano-ultra-thin high entropy alloy layer, characterized in that: The following steps are involved: S1. Weigh nickel, zinc, cadmium, indium, and copper sources in equal molar ratios and grind them in a mortar for 1 hour. Dissolve the powder in 5-10 mL of anhydrous ethanol and disperse it ultrasonically. Stir for 1-3 hours to obtain a multi-metal ion solution. S2, carbon paper activated in a plasma cleaning machine and cut into 0.785cm 2 The multi-metal ion precursor solution is absorbed and dropped onto the disc, and then vacuum-dried in an oven at 50-80° C. for 8-24 h to obtain a precursor; S3. Place the precursor in a tubular atmosphere furnace chamber filled with a mixed atmosphere. In the first stage, set the furnace chamber temperature to 200-500°C and sinter for 1-2 hours; in the second stage, set the furnace chamber temperature to 500-900°C and sinter for 30-60 minutes; in the third stage, set the furnace chamber temperature to 900-1100°C and sinter for 10-30 minutes. The heating rate in the above stages is 5-10°C / s. A high-entropy alloy composite material (NiZnInCuCd HEA / C) with a three-dimensional framework carbon fiber as the main body and loaded with NiZnInCuCd nanoparticles is obtained by gradient sintering.

2. The method for preparing a NiZnInCuCd nano-ultrathin high entropy alloy layer according to claim 1, characterized in that: The sources of nickel, zinc, cadmium, indium and copper in step S1 are any one of their sulfates, chlorides and nitrates.

3. The method for preparing a NiZnInCuCd nano-ultrathin high entropy alloy layer according to claim 1, characterized in that: The ultrasonic dispersion time in step S1 is 1 to 10 hours.

4. The method for preparing a NiZnInCuCd nano-ultrathin high entropy alloy layer according to claim 1, characterized in that: In step S2, the activation treatment time of the carbon paper in the plasma surface treatment machine is 5 to 30 minutes.

5. The method for preparing a NiZnInCuCd nano-ultrathin high entropy alloy layer according to claim 1, characterized in that: The amount of carbon paper added each time in step S2 is 5 to 100 μL / cm 2 .

6. The method for preparing a NiZnInCuCd nano-ultrathin high entropy alloy layer according to claim 1, characterized in that: In the atmosphere furnace in step S3, the atmosphere is a gas combination, namely, Ar2:H2=9:1.

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