A core-shell structured high-entropy alloy fiber material, its preparation method and application

Abstract

The present invention discloses a core-shell structured high-entropy alloy fiber material, its preparation method and application, belonging to the technical field of alloy material preparation. The method includes: dissolving a buffer in deionized water to obtain solution A, heating it and sequentially adding a complexing agent, an additional salt, a reducing agent and a soluble metal salt, stirring and dissolving to obtain solution B, then adjusting the pH of solution B, and standing at room temperature to obtain an electrolyte; ultrasonically cleaning, rinsing and drying the conductive fiber with acetone, ethanol and deionized water respectively; using a saturated calomel electrode as a reference electrode, the conductive fiber as a working electrode, and a carbon electrode rod as a counter electrode, immersing the three electrodes in the electrolyte, and using a potentiostatic electrodeposition method to perform electrodeposition on the surface of the conductive fiber to obtain a high-entropy alloy fiber. The present invention realizes the uniform electrodeposition of the high-entropy alloy on the fiber surface and obtains a high-entropy alloy fiber material with excellent conductivity.

Description

Technical Field

[0001] The present invention relates to the technical field of alloy material preparation, and more particularly to a high-entropy alloy fiber material with a core-shell structure, a preparation method thereof, and an application thereof. Background Art

[0002] High-entropy alloys (HEAs) are novel materials composed of five or more metal elements combined in a disordered arrangement. Currently, due to their multi-component structure compared with traditional alloys, high-entropy alloys have rich nanostructures and exhibit excellent mechanical, electrochemical, and magnetic properties, and are widely used in the fields of aerospace, electronic devices, and energy. However, the preparation of high-entropy alloys usually requires complex high-temperature treatments such as arc melting, laser cladding, etc. These methods consume a large amount of energy and have high costs, and it is difficult to meet the requirements of large-scale and low-temperature preparation. Electrochemical deposition (hereinafter referred to as electroplating) is a metal preparation method and application with low cost, easy to scale up, and low process temperature, and is very suitable for the synthesis of high-entropy alloys.

[0003] Electroplating is divided into a substrate and a coating. The coating is reduced from the electrolyte on the surface of the substrate under the action of an electric current, thereby achieving an increase in the performance of the substrate. Therefore, it is required that the substrate has certain electrical conductivity. Conductive fibers refer to fiber materials with electrical conductivity. These fibers have broad application potential in the fields of electrodes, composite materials, and wearable devices, and are very suitable as electroplating substrates. However, current research on fiber materials mostly focuses on the field of composite materials, and there is still a large research space for electrode and wearable electronic materials. In particular, the combination of high-entropy alloys and conductive fibers has not been deeply explored. Therefore, it is very important to use conductive fibers as substrates to realize the preparation of electroplated high-entropy alloy fibers.

[0004] However, there are still technical problems in electroplating high-entropy alloys at present, and it is necessary to achieve uniform and stable deposition of high-entropy alloys on the surface of conductive fibers. Therefore, how to develop a high-entropy alloy fiber material with a core-shell structure, a preparation method thereof, and an application thereof is an urgent problem to be solved by those skilled in the art. Summary of the Invention

[0005] In view of this, the present invention provides a high-entropy alloy fiber material with a core-shell structure, a preparation method thereof, and an application thereof.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A preparation method of a high-entropy alloy fiber material with a core-shell structure, comprising the following steps:

[0008] (1) Dissolve the buffer in deionized water to obtain solution A. Heat solution A, and then successively add a complexing agent, an additional salt, a reducing agent, and a soluble metal salt. After stirring and dissolving, obtain solution B. Let solution B stand at room temperature and adjust the pH of solution B to obtain the electrolyte solution.

[0009] The above-mentioned reducing agent is one or both of sodium hypophosphite or ascorbic acid; the above-mentioned soluble metal salt is a ferric salt, a cobalt salt, a nickel salt, a copper salt, or a zinc salt.

[0010] (2) Ultrasonically clean the conductive fiber successively with acetone, ethanol, and deionized water, then rinse with deionized water and dry it.

[0011] (3) Use a saturated calomel electrode as the reference electrode, the conductive fiber obtained in step (2) as the working electrode, and a carbon electrode rod as the counter electrode. Using the electrolyte solution obtained in step (1), perform electrodeposition on the conductive fiber using the potentiostatic electrodeposition method. The deposition potential range of the above-mentioned electrodeposition is -1 V to -2 V to obtain a core-shell structured high-entropy alloy fiber material.

[0012] In step (1), the above-mentioned buffer is one or several of boric acid, disodium hydrogen phosphate, phosphoric acid, or acetic acid; the above-mentioned complexing agent is one or several of citric acid, sodium citrate, or potassium pyrophosphate; the above-mentioned additional salt is one or several of potassium chloride, sodium chloride, or sodium sulfate.

[0013] In step (1), in solution A, the concentration of the above-mentioned buffer is 0.001 - 1 mol / L; in solution B, the concentration of the above-mentioned complexing agent is 0.001 - 1 mol / L, the concentration of the above-mentioned additional salt is 0.001 - 1 mol / L, and the concentration of the above-mentioned reducing agent is 0.001 - 1 mol / L.

[0014] The above-mentioned ferric salt is one or several of ferrous sulfate, ferrous chloride, or ferrous nitrate; the above-mentioned cobalt salt is one or several of cobalt sulfate, cobalt chloride, or cobalt nitrate; the above-mentioned nickel salt is one or several of nickel sulfate, nickel chloride, or nickel nitrate; the above-mentioned copper salt is one or several of copper sulfate, copper chloride, or copper nitrate; the above-mentioned zinc salt is one or several of zinc sulfate, zinc chloride, or zinc nitrate.

[0015] In solution B, the concentration of the above-mentioned ferric salt is 0.001 - 1 mol / L, the concentration of the above-mentioned cobalt salt is 0.001 - 1 mol / L, the concentration of the above-mentioned nickel salt is 0.001 - 1 mol / L, the concentration of the above-mentioned copper salt is 0.0001 - 0.1 mol / L, and the concentration of the above-mentioned zinc salt is 0.001 - 1 mol / L.

[0016] In step (1), heat solution A to 40 - 100 °C, let solution B stand at room temperature for 2 - 8 hours, and adjust the pH of solution B to 1 - 5.

[0017] In step (2), the ultrasonic treatment time of the conductive fiber is 0 - 100 min, the ultrasonic power is 85 W, the drying temperature is 50 - 80 °C, and the drying time is 2 - 10 hours;

[0018] In step (3), the time of the above electro - deposition is 1 - 100 min, and the temperature of the electro - deposition is 20 - 100 °C.

[0019] Furthermore, in step (2), the above - mentioned conductive fiber substrate is a carbon fiber, a metal conductive fiber or a polymer conductive fiber; the diameter of the conductive fiber is 5 - 10 μm, the fiber length is 0.1 - 5 cm, and the surface resistance is < 5 mΩ·cm 2 . Selecting a suitable conductive fiber substrate can achieve uniform and stable deposition of the high - entropy alloy. At the same time, based on the weaving properties of the high - entropy alloy fiber, it is beneficial to the development of high - entropy alloy fibers in the field of flexible electronic devices. The conductive fiber is an excellent conductor, which can ensure the stable deposition of high - entropy alloy particles during the electro - deposition process.

[0020] Even further, in step (2), the above - mentioned metal conductive fiber is a metal titanium fiber, a metal silver fiber, etc., and the polymer conductive fiber is a conductive polypyrrole fiber and a conductive PEDOT fiber.

[0021] Even further, the pH of solution B is adjusted by an acid solution and an alkali solution. The acid solution is a H2SO4 solution with a concentration of 1 mol / L, and the alkali solution is a NaOH solution with a concentration of 1 mol / L. By mixing the acid solution and the alkali solution, the pH of the electrolyte is stabilized within a predetermined range of 1 - 5, which can ensure the stability of the electroplating process and obtain uniform core - shell - structured high - entropy alloy fibers.

[0022] The present invention also provides a core - shell - structured high - entropy alloy fiber material prepared by the above method.

[0023] Furthermore, the fiber diameter of the high - entropy alloy fiber material is 5 - 10 μm, the fiber length is 0.1 - 5 cm, the surface particle size is 100 - 1000 nm, the thickness of the shell layer structure is 100 - 1000 nm, and the average contact impedance of the high - entropy alloy fiber material at a frequency of 100 Hz is 33.30 ± 1.03 kΩ, and the average solution impedance is 22.42 ± 2.34 Ω. It defines the physical form and surface microstructure of the core - shell - structured high - entropy alloy fiber, and emphasizes that the obtained high - entropy alloy particles are of nanoscale size.

[0024] Furthermore, the mass percentages of iron, cobalt, nickel, copper, and zinc in the core-shell structured high-entropy alloy fiber material are 1% to 50% respectively. Controlling the content of elements can ensure the elemental uniformity of the high-entropy alloy fiber and prevent the excessive content of a single element from affecting the deposition process, particle size, etc. of the fiber material.

[0025] The present invention also provides an application of the above-mentioned core-shell structured high-entropy alloy fiber material in flexible electronic devices and electrode development.

[0026] Advantages of the present invention:

[0027] By optimizing the composition of the electrolyte, the method of the present invention realizes the uniform deposition of the high-entropy alloy and obtains a high-entropy alloy fiber material with excellent electrical conductivity and mechanical stability.

[0028] By optimizing the concentrations of the components in solution B, the present invention can precisely control the reduction of metal ions, solubility, and deposition rate during the electroplating process, thereby improving the uniformity and stability of the deposition process of the high-entropy alloy on the surface of the conductive fiber.

[0029] Introducing metal elements by adding metal salts in the present invention can provide more choices for the metal sources of the high-entropy alloy, precisely control the electroplating process of the high-entropy alloy, and improve the uniformity of the alloy. Introducing metal elements by adding metal salts broadens the source of metal elements and enriches the selection of high-entropy alloys. It can precisely control the content of various elements during the electroplating process of the high-entropy alloy, improve the electrical conductivity of the alloy, and standing solution B can stabilize the electrolyte system and keep the conductive fiber stable during the deposition process.

[0030] Heating solution A in the present invention is to provide an external temperature source for the electrolyte system, increase the solubility of the system, which is beneficial to dissolve the subsequent added complexing agent, additional salt, reducing agent, and soluble metal salt, and provide a stable solution environment for the electrolyte. Standing solution B can stabilize the electrolyte system and keep the conductive fiber stable during the deposition process. Ultrasonic waves can clean the surface of the conductive fiber, remove the impurities generated on the surface of the fiber during the production and manufacturing process, increase the contact sites between the electrolyte and the conductive fiber during the electroplating process, and promote the uniform and stable progress of the electroplating process. By optimizing the deposition time, the method of the present invention realizes the uniform deposition of the high-entropy alloy and obtains a high-entropy alloy fiber material with excellent electrical conductivity and mechanical stability. Obtaining a uniform high-entropy alloy can enable the nano-high-entropy alloy particles to wrap the conductive fiber, improve the electrical conductivity of the fiber, and add a micro-structure to the fiber surface, increasing the number of active sites.

[0031] The deposition potential range selected for electrodeposition in the present invention is from -1 V to -2 V, which is more conducive to the deposition of multiple metal elements, avoiding the inability to reduce metal ions due to too positive a potential during the experiment and the evolution of hydrogen due to too negative a potential. An overly negative potential will cause the electrolysis of water to produce hydrogen, which will not only affect the electrodeposition process but may also lead to uneven deposition layers or bubble defects.

[0032] Compared with traditional binary alloy systems such as traditional iron-nickel alloys, in terms of the preparation process: the preparation of the high-entropy alloy in the present invention needs to solve the problem of uniform mixing of multiple elements, avoid the formation of intermetallic compounds and achieve the uniform distribution of five elements, and the process method is relatively difficult. The production of ordinary binary alloys relies on traditional alloy processes, with a mature system and simple composition.

[0033] The carbon-based high-entropy alloy fibers prepared by the method of the present invention have a nanoscale microstructure and achieve a tight combination of the high-entropy alloy and the conductive fiber. The present invention uses acetone, ethanol, and deionized water to clean the electrolyte residue on the surface of the electroplated material, which is beneficial to the subsequent drying of the material. The temperature of electrodeposition is lower than that of other deposition methods. Traditional metal methods such as sputtering deposition of HEA are obtained by high-temperature sintering. The temperature of electrodeposition is 20~100 °C, and uniform deposition of the high-entropy alloy is achieved under low-temperature conditions, obtaining a high-entropy alloy fiber material with excellent electrical conductivity and mechanical stability. The preparation process of the present invention is simple and low-cost, and the obtained material has broad application prospects in the fields of electrocatalysis, energy storage, and structural composite materials.

[0034] The carbon-based high-entropy alloy fiber material of the present invention has a nanoscale microstructure and achieves a tight combination of the high-entropy alloy and the conductive fiber, and is a high-entropy alloy fiber material with excellent electrical conductivity and mechanical stability.

[0035] The core-shell structured high-entropy alloy fiber material has stronger application potential in flexible electronic devices and electrode development by improving the electrical conductivity of the raw materials and providing a larger specific surface area and more active sites with the help of nanoscale particles, and has broad prospects especially in the fields of flexible electronic devices and electrode materials. Description of the Drawings

[0036] Figure 1 SEM image of the core-shell structured high-entropy alloy fiber material prepared in Example 1.

[0037] Figure 2 EDS image of the core-shell structured high-entropy alloy fiber material prepared in Example 1.

[0038] Figure 3 Contact impedance comparison between the core-shell structured high-entropy alloy fiber material prepared in Example 1 and a commercial conductive material.

[0039] Figure 4 Comparison of the solution impedance between the core-shell structured high-entropy alloy fiber material prepared in Example 1 and commercial conductive materials.

[0040] Figure 5 Element content ratios of the core-shell structured high-entropy alloy fiber materials prepared in Examples 1 to 5.

[0041] Figure 6 In it, Figure a is the cyclic voltammetry test of the working electrode in the electrolyte solution, Figure b is the cyclic voltammetry test of the working electrode in a single metal element solution, Figure c is the deposition curve at different deposition potentials, and Figure d is the impedance performance of the electrodes obtained at different deposition potentials. Specific Embodiments

[0042] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0043] Example 1

[0044] A preparation method of a core-shell structured high-entropy alloy fiber material includes the following steps:

[0045] (1) Dissolve boric acid in deionized water to obtain solution A. In solution A, the concentration of boric acid is 0.5 mol / L. Heat solution A to 40°C, and then sequentially add citric acid, sodium citrate, potassium chloride, sodium hypophosphite, ferrous sulfate, cobalt sulfate, nickel chloride, copper chloride, and zinc nitrate under heating conditions. After stirring and dissolving, obtain solution B. In solution B, the concentration of citric acid is 0.5 mol / L, the concentration of sodium citrate is 0.1 mol / L, the concentration of potassium chloride is 0.05 mol / L, the concentration of sodium hypophosphite is 0.01 mol / L, the concentration of ferrous sulfate is 0.05 mol / L, the concentration of cobalt sulfate is 0.01 mol / L, the concentration of nickel chloride is 0.01 mol / L, the concentration of copper chloride is 0.0001 mol / L, and the concentration of zinc nitrate is 0.01 mol / L. Let solution B stand at room temperature for 2 hours, and then adjust the pH of solution B to 2 with a 1 mol / L H2SO4 solution to obtain an electrolyte solution;

[0046] (2) Fibers with a diameter of 8 μm, a length of 2 cm, and a planar resistance < 5 mΩ cm 2The carbon fiber surface was ultrasonically treated with acetone, ethanol, and deionized water in sequence for 100 min at an ultrasonic power of 85 W, then rinsed with deionized water and ethanol, and dried at 80 °C for 2 hours;

[0047] (3) Using the electrolyte obtained in step (1), electroplating was carried out on the carbon fiber by potentiostatic electrodeposition. A saturated calomel electrode was used as the reference electrode, the carbon fiber obtained in step (2) was used as the working electrode, and a carbon electrode rod was used as the counter electrode. The deposition potential was -1.25 V, the electrodeposition temperature was 20 °C, and the electrodeposition time was 10 min to obtain a core-shell structured high-entropy alloy fiber material. The fiber diameter of the obtained core-shell structured high-entropy alloy fiber material was 8 μm, the fiber length was 2 cm, the surface particle size was 300 - 600 nm, and the shell layer structure thickness was about 100 - 300 nm.

[0048] Such as Figure 1 , is the SEM image of the core-shell structured high-entropy alloy fiber material prepared in this example. Among them, the surface particles are the shells of the core-shell structure, and the carbon fiber is the core of the core-shell structure. It can be seen from the SEM image that a stable synthesis of the high-entropy alloy is formed and is evenly distributed.

[0049] Such as Figure 2 , is the EDS image of the core-shell structured high-entropy alloy fiber material prepared in this example. It can be seen from the EDS image that the five metal elements of iron, cobalt, nickel, copper, and zinc have all been successfully deposited in the same area and are evenly distributed.

[0050] Such as Figure 3 , is the comparison of the contact impedance between the core-shell structured high-entropy alloy fiber material prepared in this example and commercial materials, indicating that the core-shell structured high-entropy alloy fiber material has a smaller resistance in the case of skin contact. Among them, at a frequency of 100 Hz, the average contact impedance of commercial materials is 171.40 kΩ, the average contact impedance of planar HEA is 43.32 kΩ, and the average contact impedance of fiber HEA is 33.30 kΩ.

[0051] The commercial material is a commercial two-dimensional conductive material, the planar HEA is a HEA material obtained by electrodeposition on a two-dimensional plane, and the fiber HEA is the core-shell structured high-entropy alloy fiber material of Example 1.

[0052] Such as Figure 4, showing the comparison of the solution impedance between the core-shell structured high-entropy alloy fiber material prepared in this example and the commercial conductive material, indicating that the core-shell structured high-entropy alloy fiber material has a smaller resistance in the electrolyte environment of phosphate buffer solution (PBS). Among them, at a frequency of 100 Hz, the average solution impedance of the commercial material is 234.03 kΩ, the average solution impedance of the planar HEA is 123.44 kΩ, and the average solution impedance of the fiber HEA is 22.42 kΩ.

[0053] Example 2

[0054] Preparation method of the core-shell structured high-entropy alloy fiber material, comprising the following steps:

[0055] (1) Dissolve acetic acid and disodium hydrogen phosphate in deionized water to obtain solution A. In solution A, the concentration of acetic acid is 0.001 mol / L, and the concentration of disodium hydrogen phosphate is 0.001 mol / L. Heat solution A to 100 °C, and then sequentially add citric acid, sodium citrate, sodium chloride, ascorbic acid, ferrous chloride, cobalt nitrate, nickel sulfate, copper sulfate, and zinc sulfate under heating conditions, and stir to dissolve to obtain solution B. In solution B, the concentration of citric acid is 0.05 mol / L, the concentration of sodium citrate is 0.001 mol / L, the concentration of sodium chloride is 0.05 mol / L, the concentration of ascorbic acid is 0.001 mol / L, the concentration of ferrous chloride is 1 mol / L, the concentration of cobalt nitrate is 0.05 mol / L, the concentration of nickel sulfate is 0.01 mol / L, the concentration of copper sulfate is 0.0001 mol / L, and the concentration of zinc sulfate is 0.001 mol / L. Let solution B stand at room temperature for 8 hours, and then adjust the pH of solution B to 5 with 1 mol / L NaOH solution to obtain the electrolyte;

[0056] (2) The polyvinylpyrrole conductive fiber with a fiber diameter of 5 μm, a fiber length of 0.1 cm, and a planar resistance < 5 mΩ cm 2 The surface of the polyvinylpyrrole conductive fiber is ultrasonically treated with deionized water for 0 min, the ultrasonic power is 85 W, and then it is rinsed with deionized water and ethanol and dried at 50 °C for 10 hours;

[0057] (3) Using the electrolyte obtained in step (1), electroplate the polypyrrole conductive fiber by potentiostatic electrodeposition. Use the saturated calomel electrode as the reference electrode, the polypyrrole conductive fiber obtained in step (2) as the working electrode, and the carbon electrode rod as the counter electrode. The deposition potential is -1.75 V, the temperature of electrodeposition is 40 °C, and the electrodeposition time is 100 min to obtain a core-shell structured high-entropy alloy fiber material. The fiber diameter of the obtained core-shell structured high-entropy alloy fiber material is 5 μm, the fiber length is 0.1 cm, the surface particle size is 200 - 400 nm, and the shell structure thickness is 600 - 1000 nm.

[0058] Example 3

[0059] Preparation method of a core-shell structured high-entropy alloy fiber material, comprising the following steps:

[0060] (1) Dissolve phosphoric acid in deionized water to obtain solution A. In solution A, the concentration of phosphoric acid is 0.001 mol / L. Heat solution A to 40 °C, and then sequentially add citric acid, sodium citrate, sodium sulfate, sodium hypophosphite, ferrous chloride, cobalt chloride, nickel chloride, copper chloride, and zinc chloride under heating conditions. After stirring and dissolving, obtain solution B. In solution B, the concentration of citric acid is 1 mol / L, the concentration of sodium citrate is 1 mol / L, the concentration of sodium sulfate is 0.001 mol / L, the concentration of sodium hypophosphite is 1 mol / L, the concentration of ferrous chloride is 0.001 mol / L, the concentration of cobalt chloride is 0.035 mol / L, the concentration of nickel nitrate is 1 mol / L, the concentration of copper nitrate is 0.001 mol / L, and the concentration of zinc chloride is 1 mol / L. Let solution B stand at room temperature for 2 hours, and then adjust the pH of solution B to 3 using a 1 mol / L H2SO4 solution to obtain the electrolyte;

[0061] (2) Ultrasonically treat the surface of the conductive PEDOT fiber with a fiber diameter of 10 μm, a fiber length of 1 cm, and a planar resistance < 5 mΩ·cm 2 with deionized water for 20 min, with an ultrasonic power of 85 W, and then rinse with deionized water and ethanol, and dry at 80 °C for 4 hours;

[0062] (3) Using the electrolyte obtained in step (1), electroplate the conductive PEDOT fiber by potentiostatic electrodeposition. Use the saturated calomel electrode as the reference electrode, the conductive PEDOT fiber obtained in step (2) as the working electrode, and the carbon electrode rod as the counter electrode. The deposition potential is -2 V, the temperature of electrodeposition is 60 °C, and the electrodeposition time is 1 min to obtain a core-shell structured high-entropy alloy fiber material. The fiber diameter of the obtained core-shell structured high-entropy alloy fiber material is 10 μm, the fiber length is 1 cm, the surface particle size is about 400 - 600 nm, and the thickness of the shell structure is 100 - 200 nm.

[0063] Example 4

[0064] Preparation method of a core-shell structured high-entropy alloy fiber material, comprising the following steps:

[0065] (1) Dissolve boric acid in deionized water to obtain solution A. In solution A, the concentration of boric acid is 1 mol / L. Heat solution A to 50 °C, and then sequentially add citric acid, sodium citrate, potassium pyrophosphate, sodium chloride, sodium hypophosphite, ferrous sulfate, cobalt sulfate, nickel nitrate, copper chloride, and zinc chloride under heating conditions. After stirring and dissolving, obtain solution B. In solution B, the concentration of citric acid is 0.5 mol / L, the concentration of sodium citrate is 1 mol / L, the concentration of potassium pyrophosphate is 0.001 mol / L, the concentration of sodium chloride is 1 mol / L, the concentration of sodium hypophosphite is 0.01 mol / L, the concentration of ferrous sulfate is 0.1 mol / L, the concentration of cobalt sulfate is 1 mol / L, the concentration of nickel nitrate is 0.05 mol / L, the concentration of copper sulfate is 0.001 mol / L, and the concentration of zinc sulfate is 0.005 mol / L. Let solution B stand at room temperature for 8 hours, and then adjust the pH of solution B to 1 using a 1 mol / L H2SO4 solution to obtain the electrolyte;

[0066] (2) Ultrasonically treat titanium fibers with a fiber diameter of 6 μm, a fiber length of 1.5 cm, and a planar resistance <5 mΩ cm 2 for 60 min with an ultrasonic power of 85 W, then rinse with deionized water and ethanol, and dry at 60 °C for 6 hours;

[0067] (3) Using the electrolyte obtained in step (1), electroplate the titanium fiber by potentiostatic electrodeposition. Use the saturated calomel electrode as the reference electrode, the titanium fiber obtained in step (2) as the working electrode, and the carbon electrode rod as the counter electrode. The deposition potential is -1 V, the temperature of electrodeposition is 80 °C, and the electrodeposition time is 20 min to obtain a high-entropy alloy fiber material with a core-shell structure. The fiber diameter of the obtained high-entropy alloy fiber material with a core-shell structure is 6 μm, the fiber length is 1.5 cm, the surface particle size is 600-1000 nm, and the thickness of the shell structure is 100-200 nm.

[0068] Example 5

[0069] A method for preparing a high-entropy alloy fiber material with a core-shell structure, comprising the following steps:

[0070] (1) Dissolve boric acid in deionized water to obtain solution A. In solution A, the concentration of boric acid is 1 mol / L. Heat solution A to 60 °C, and then sequentially add citric acid, sodium citrate, potassium chloride, sodium hypophosphite, ferrous sulfate, cobalt sulfate, nickel sulfate, copper sulfate, and zinc sulfate under heating conditions. After stirring and dissolving, obtain solution B. In solution B, the concentration of citric acid is 0.001 mol / L, the concentration of sodium citrate is 0.35 mol / L, the concentration of potassium chloride is 0.05 mol / L, the concentration of sodium hypophosphite is 0.005 mol / L, the concentration of ferrous sulfate is 1 mol / L, the concentration of cobalt chloride is 1 mol / L, the concentration of nickel sulfate is 0.05 mol / L, the concentration of copper sulfate is 0.1 mol / L, and the concentration of zinc sulfate is 0.05 mol / L. Let solution B stand at room temperature for 5 hours, and then adjust the pH of solution B to 1 with a 1 mol / L H2SO4 solution to obtain the electrolyte;

[0071] (2) Ultrasonically treat the surface of silver fibers with a fiber diameter of 8 μm, a fiber length of 5 cm, and a planar resistance <5 mΩ cm 2 for 45 min with a ultrasonic power of 85 W, then rinse with deionized water and ethanol, and dry at 60 °C for 5 hours;

[0072] (3) Using the electrolyte obtained in step (1), electroplate the silver fibers by potentiostatic electrodeposition. Use the saturated calomel electrode as the reference electrode, the silver fibers obtained in step (2) as the working electrode, and the carbon electrode rod as the counter electrode. The deposition potential is -1.5 V, the temperature of electrodeposition is 100 °C, and the electrodeposition time is 20 min to obtain a core-shell structured high-entropy alloy fiber material. The fiber diameter of the obtained core-shell structured high-entropy alloy fiber material is 8 μm, the fiber length is 5 cm, the surface particle size is 100 - 300 nm, and the thickness of the shell layer structure is 200 - 400 nm.

[0073] As Figure 5 , it is a data chart of the element content of the core-shell structured high-entropy alloy fiber materials prepared in Examples 1 - 5. From the content of each element, the deposition of the five metal elements can be seen, indicating that the stable synthesis of the core-shell structured high-entropy alloy fibers can be stably achieved by this method.

[0074] The present invention realizes the uniform and stable deposition of the high-entropy alloy on the surface of the conductive fiber, and while maintaining the characteristics of the conductive fiber, further improves the electrical properties of the conductive fiber.

[0075] Selection of the electrodeposition potential range:

[0076] In the present invention, through cyclic voltammetry, an electrodeposition interval is found between 0 V and -0.6 V ( Figure 6 a and b diagrams), so -1 V, which is more negative than -0.6 V, is selected as the starting research position. However, during the electrodeposition process, although a high-entropy alloy can be obtained at a deposition potential of -1 V, there is an instantaneous change in current before electrodeposition, which is the electrode charging phenomenon caused by insufficient electrodeposition voltage. And when it reaches -2 V, although the preparation of the high-entropy alloy is achieved, hydrogen gas is easily precipitated during the whole deposition process, affecting the stability of the high-entropy alloy preparation process ( Figure 6 c diagram), while the preparation process at -1.25 V is stable, and the obtained material has lower impedance and better electrical conductivity. Therefore, -1.25 V is considered to be the most suitable deposition potential ( Figure 6 d diagram). In the present invention, within a range of deposition potentials centered on -1.25 V, the preparation of the high-entropy alloy can be obtained by selecting from -1 V to -2 V.

[0077] Regarding the selection of -1 V: Selecting -1 V is to ensure that the selected potential is negative. For the multi-element deposition process, since there are cases where the standard potential of the target elements is positive, selecting a negative potential is more conducive to the deposition of multiple metal elements and avoids the inability to reduce metal ions due to the potential being too positive during the experiment.

[0078] Regarding the selection of -2 V: The selection of -2 V is to avoid hydrogen evolution caused by an overly negative potential. An overly negative potential will cause the electrolysis of water to produce hydrogen, which will not only affect the electrodeposition process, but may also lead to uneven deposition layers or bubble defects. However, a high-entropy alloy can be obtained.

[0079] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A preparation method of a core-shell structured high-entropy alloy fiber material, characterized in that, It includes the following steps: (1) Dissolve a buffer in deionized water to obtain solution A. Heat solution A, and then sequentially add a complexing agent, an additional salt, a reducing agent, and a soluble metal salt. After stirring and dissolving, obtain solution B. Let solution B stand at room temperature and adjust the pH of solution B to obtain an electrolyte; The reducing agent is one or both of sodium hypophosphite or ascorbic acid; the soluble metal salt is a ferric salt, a cobalt salt, a nickel salt, a copper salt, or a zinc salt; (2) Ultrasonically clean the conductive fiber successively with acetone, ethanol, and deionized water, then rinse with deionized water and dry; (3) Using a saturated calomel electrode as the reference electrode, the conductive fiber obtained in step (2) as the working electrode, and a carbon electrode rod as the counter electrode, and adopting the electrolyte obtained in step (1), perform electrodeposition on the conductive fiber using a potentiostatic electrodeposition method. The deposition potential of the electrodeposition is -1.25V to obtain a core-shell structured high-entropy alloy fiber material; In step (1), the buffer is one or several of boric acid, disodium hydrogen phosphate, phosphoric acid, or acetic acid; the complexing agent is one or several of citric acid, sodium citrate, or potassium pyrophosphate; the additional salt is one or several of potassium chloride, sodium chloride, or sodium sulfate; In step (1), in solution A, the concentration of the buffer is 0.001 - 1 mol / L; in solution B, the concentration of the complexing agent is 0.001 - 1 mol / L, the concentration of the additional salt is 0.001 - 1 mol / L, and the concentration of the reducing agent is 0.001 - 1 mol / L; The ferric salt is one or several of ferrous sulfate, ferrous chloride, or ferrous nitrate; the cobalt salt is one or several of cobalt sulfate, cobalt chloride, or cobalt nitrate; the nickel salt is one or several of nickel sulfate, nickel chloride, or nickel nitrate; the copper salt is one or several of copper sulfate, copper chloride, or copper nitrate; the zinc salt is one or several of zinc sulfate, zinc chloride, or zinc nitrate; In solution B, the concentration of the ferric salt is 0.001 - 1 mol / L, the concentration of the cobalt salt is 0.001 - 1 mol / L, the concentration of the nickel salt is 0.001 - 1 mol / L, the concentration of the copper salt is 0.0001 - 0.1 mol / L, and the concentration of the zinc salt is 0.001 - 1 mol / L; In step (1), heat solution A to 40 - 100°C, let solution B stand at room temperature for 2 - 8 hours, and adjust the pH of solution B to 1 - 5; adjust the pH of solution B using an acid solution and an alkali solution. The above acid solution is a 1 mol / L H2SO4 solution, and the above alkali solution is a 1 mol / L NaOH solution; In step (2), the ultrasonic treatment time of the conductive fiber is 0 - 100 min, the ultrasonic power is 85W, the drying temperature is 50 - 80°C, and the drying time is 2 - 10 hours; In step (3), the time of the electrodeposition is 1 - 100 min, and the temperature of the electrodeposition is 20 - 100°C; In step (2), the conductive fiber is a carbon fiber; the diameter of the conductive fiber is 5 to 10 μm, the length of the conductive fiber is 0.1 to 5 cm, and the surface resistance < 5 mΩ·cm 2 ; The fiber diameter of the high-entropy alloy fiber material is 5-10 μm, the fiber length is 0.1-5 cm, the surface particle size is 100-1000 nm, the shell structure thickness is 100-1000 nm, and the average contact impedance of the high-entropy alloy fiber material at a frequency of 100 Hz is 33.30 ± 1.03 kΩ, and the average solution impedance is 22.42 ± 2.34 Ω.

2. Application of the core-shell structured high-entropy alloy fiber material prepared by the method according to claim 1 in flexible electronic devices and electrode development.

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