High-entropy alloy / carbon nanotube composite material, preparation method and application thereof

Abstract

The application discloses a high-entropy alloy / carbon nanotube composite material and a preparation method and application thereof. The high-entropy alloy / carbon nanotube composite material comprises a carbon nanotube base, a first high-entropy alloy structure and a second high-entropy alloy structure. The carbon nanotube base comprises at least one carbon nanotube. The first high-entropy alloy structure is distributed on the surface of the carbon nanotube. The second high-entropy alloy structure is coated on the carbon nanotube and forms a high-entropy alloy / carbon nanotube core-sheath structure with the carbon nanotube. The high-entropy alloy / carbon nanotube composite self-supporting electrode material with the nanometer microsphere and the core-sheath structure is constructed by growing the high-entropy alloy nanometer microsphere and the high-entropy alloy / carbon nanotube core-sheath structure in two steps through transient ultrahigh temperature heating, and the catalytic activity is improved to meet the application requirements in the fields of high-performance catalysis and battery electrodes.

Description

TECHNICAL FIELD

[0001] The application particularly relates to a high-entropy alloy / carbon nanotube composite material with multiple micro-nano structures and a preparation method and application thereof, and belongs to the technical field of micro-nano materials. BACKGROUND

[0002] The unique high-entropy effect and composite effect endow the high-entropy alloy with high catalytic activity and durability, and the high-entropy alloy has broad application prospects in the fields of oxygen evolution reaction (OER), oxygen reduction reaction (ORR), hydrogen evolution reaction (HER) and carbon dioxide reduction (CO2RR). However, in addition to the composition, the size, morphology and micro-nano structure of the high-entropy alloy will greatly affect the electrochemical performance thereof, and the structure regulation is also a key factor for improving the performance thereof.

[0003] The carbon nanotube has high conductivity, mechanical properties and stability, and is an excellent current collector material. The combination of the high-entropy alloy and the carbon nanotube can produce a high-entropy alloy / carbon nanotube composite electrode material, which can exert the advantages of both and form a light-weight high-performance electrode material. Further enriching the structure of the high-entropy alloy to form a multiple structure of the high-entropy alloy / carbon nanotube coaxial body and the high-entropy alloy microsphere can further exert the advantages of the high-entropy alloy / carbon nanotube composite structure and improve the electrode performance thereof.

[0004] However, the existing macro-preparation technology of the high-entropy alloy cannot combine the high-entropy alloy and the carbon nanotube organically, and construct a self-supporting high-entropy alloy / carbon nanotube composite electrode material with high conductivity and high electrochemical activity. The ultra-high temperature transient heating technology can be developed by using the ultra-high thermal stability, low density and low heat capacity characteristics of the carbon nanotube, so as to generate an ultra-high temperature of >2000℃ in an ultra-short time of milliseconds, thereby rapidly and efficiently preparing the micro-nano structure of the high-entropy alloy in situ on the surface of the carbon nanotube. The size of the high-entropy alloy nanomicrosphere formed can be effectively controlled by adjusting the peak temperature, pulse frequency, duty cycle and duration of the ultra-high temperature transient heating; and the composition of the high-entropy alloy nanomicrosphere can be regulated by changing the type of the precursor, so that the high-entropy nanomicrosphere can be prepared according to the application requirements. However, the ultra-high temperature transient preparation technology of the high-entropy alloy is still in its infancy, and the understanding of the mechanism thereof is still relatively shallow, and there are the following problems:

[0005] 1) The existing macro-preparation technology of the high-entropy alloy cannot combine the high-entropy alloy and the carbon nanotube organically, and construct a self-supporting high-entropy alloy / carbon nanotube composite electrode material with high conductivity and high electrochemical activity.

[0006] 2) The wettability of the high-entropy alloy formed by the uniform mixing of multiple elements and the carbon nanotube is different, and there is no clear research result for the wettability between the high-entropy alloy and the carbon nanotube, and how to improve the wettability of the high-entropy alloy and the carbon nanotube and make them closely combined still has problems.

[0007] 3) The existing transient ultrahigh temperature heating technology based on carbon nanotube and graphene cannot effectively adjust the composite structure, and has not yet been able to construct a composite micro-nano structure with both core-sheath and microspheres. SUMMARY

[0008] The main purpose of the present application is to provide a high-entropy alloy / carbon nanotube composite material with multiple micro-nano structures and its preparation method and application, so as to overcome the shortcomings of the prior art. The preparation method of the high-entropy alloy / carbon nanotube composite material with multiple micro-nano structures provided by the present application can obtain a high-entropy alloy / carbon nanotube composite electrode with multiple micro-nano structures of core-sheath and microspheres based on the transient ultrahigh temperature heating technology. In addition, the transient ultrahigh temperature heat is highly concentrated, can be micro-heated, and the preparation speed is extremely fast. It is a low-energy nanomaterial thermal synthesis preparation method, which meets the development strategy of "carbon standard and carbon neutralization".

[0009] To achieve the foregoing purposes of the application, the technical solutions adopted by the present application include:

[0010] In one aspect, the present application provides a high-entropy alloy / carbon nanotube composite material with multiple micro-nano structures, comprising a carbon nanotube matrix, a first high-entropy alloy structure and a second high-entropy alloy structure. The carbon nanotube matrix comprises at least one carbon nanotube. The first high-entropy alloy structure is distributed on the surface of the carbon nanotube. The second high-entropy alloy structure coats the carbon nanotube and forms a high-entropy alloy / carbon nanotube core-sheath structure with the carbon nanotube.

[0011] Further, the first high-entropy alloy structure is distributed at least at the defects on the surface of the carbon nanotube.

[0012] Further, the first high-entropy alloy structure is in the form of microspheres.

[0013] Further, the first high-entropy alloy structure is in the form of microspheres with micro-nano scale.

[0014] Further, the diameter of the first high-entropy alloy structure is 1 nm-500 μm.

[0015] Further, the carbon nanotube is completely wrapped by the second high-entropy alloy structure.

[0016] Further, the second high-entropy alloy structure is in the form of a tube shell structure wrapping the carbon nanotube.

[0017] Further, the thickness of the second high-entropy alloy structure is 0.1-500 nm.

[0018] Further, part of the first high-entropy alloy structure is embedded in the second high-entropy alloy structure.

[0019] Further, the first high-entropy alloy structure and the second high-entropy alloy structure comprise the same, part of the same or different metal elements.

[0020] Further, the first high-entropy alloy structure and the second high-entropy alloy structure comprise at least one selected metal element capable of infiltrating the carbon nanotube.

[0021] Further, the selected metal element includes nickel, titanium, chromium or iron, but is not limited thereto.

[0022] Further, the first high-entropy alloy structure and the second high-entropy alloy structure can be chromium-manganese-iron-cobalt-nickel high-entropy alloy, titanium-zirconium-hafnium-niobium-tantalum high-entropy alloy, iron-cobalt-nickel-vanadium-sulfur high-entropy alloy or platinum-cobalt-nickel-iron-copper high-entropy alloy, etc.

[0023] Further, the carbon nanotube substrate includes a carbon nanotube film or a carbon nanotube fiber formed by a plurality of carbon nanotubes.

[0024] Further, the diameter of the carbon nanotube is 0.4-100 nm.

[0025] The present application also provides a preparation method of a high-entropy alloy / carbon nanotube composite material with multiple micro-nano structures, comprising:

[0026] forming a first high-entropy alloy precursor on the surface of the carbon nanotube;

[0027] transiently heating the first high-entropy alloy precursor to a first temperature to convert the first high-entropy alloy precursor into a first high-entropy alloy structure, wherein the first high-entropy alloy structure is distributed at intervals on the surface of the carbon nanotube;

[0028] forming a second high-entropy alloy precursor on the surface of the carbon nanotube;

[0029] transiently heating the second high-entropy alloy precursor to a second temperature, wherein the second temperature is less than the first temperature, to convert the second high-entropy alloy precursor into a second high-entropy alloy structure, wherein the second high-entropy alloy structure covers the carbon nanotube and forms a high-entropy alloy / carbon nanotube core-sheath structure with the carbon nanotube.

[0030] In a more specific embodiment, the preparation method specifically comprises: introducing a first pulse current into the carbon nanotube, and spontaneously heating the first high-entropy alloy precursor to the first temperature by the carbon nanotube under the effect of current heat.

[0031] Further, the first pulse current has a magnitude of 1-1000 A.

[0032] Further, the first pulse current has a frequency of 0.1-1000 Hz.

[0033] Further, the first pulse current has a duty cycle of 10%-90%.

[0034] Further, the first pulse current has a total duration of 1 ms-1 min.

[0035] In a more specific embodiment, the preparation method specifically comprises: introducing a second pulse current into the carbon nanotube, and heating the second high-entropy alloy precursor to a second temperature by self-heating of the carbon nanotube under the action of current heating effect.

[0036] Further, the second pulse current has a magnitude of 0.5-800 A.

[0037] Further, the second pulse current has a frequency of 0-0.1 Hz, and it is to be noted that the frequency of the second pulse current is greater than 0 Hz.

[0038] Further, the second pulse current has a duty cycle of 10%-90%.

[0039] Further, the second pulse current has a total duration of 100 ms-10 min.

[0040] Further, the preparation method specifically comprises: transiently heating the temperature of the first high-entropy alloy precursor to a first temperature in an inert environment.

[0041] Further, the preparation method specifically comprises: transiently heating the temperature of the second high-entropy alloy precursor to a second temperature in an inert environment.

[0042] Further, the second temperature is 50-80% of the first temperature.

[0043] Further, the first temperature is 1000-3000 K or higher.

[0044] Further, the second temperature is 800-2400 K.

[0045] In a more specific embodiment, the preparation method specifically comprises: mixing the first high-entropy alloy precursor with a first solvent to form a first high-entropy alloy precursor solution, coating the first high-entropy alloy precursor solution on the surface of the carbon nanotube, or immersing the carbon nanotube in the first high-entropy alloy precursor solution and then taking it out, so that the first high-entropy alloy precursor is loaded on the surface of the carbon nanotube.

[0046] Further, the first solvent is an organic solvent that can infiltrate the carbon nanotube.

[0047] In a more specific embodiment, the preparation method specifically comprises: mixing the second high-entropy alloy precursor with a second solvent to form a second high-entropy alloy precursor solution, coating the second high-entropy alloy precursor solution on the surface of the carbon nanotube on which the first high-entropy alloy structure is formed, or immersing the carbon nanotube on which the first high-entropy alloy structure is formed in the second high-entropy alloy precursor solution and then taking it out, so that the second high-entropy alloy precursor is loaded on the surface of the carbon nanotube.

[0048] Further, the second solvent is an organic solvent that can infiltrate the carbon nanotube.

[0049] Further, the first high-entropy alloy precursor and the second high-entropy alloy precursor are a mixture formed by metal salts and / or metal organic compounds, the mixture includes at least five metal elements, and the mixture includes at least one selected metal element that can infiltrate the carbon nanotube.

[0050] Further, the selected metal element includes nickel element, titanium element, chromium element or iron element, but is not limited thereto.

[0051] Further, the metal elements included in the first high-entropy alloy precursor and the second high-entropy alloy precursor are completely the same, partially the same or completely different.

[0052] Further, the material of the first high-entropy alloy structure and the second high-entropy alloy structure can be chromium-manganese-iron-cobalt-nickel high-entropy alloy, titanium-zirconium-hafnium-niobium-tantalum high-entropy alloy, iron-cobalt-nickel-vanadium-sulfur high-entropy alloy or platinum-cobalt-nickel-iron-copper high-entropy alloy, etc.

[0053] Further, the first high-entropy alloy structure is distributed at least at defects on the surface of the carbon nanotube.

[0054] Further, the first high-entropy alloy structure is in the form of microspheres.

[0055] Further, the first high-entropy alloy structure is in the form of microspheres with micro-nano scale.

[0056] Further, the diameter of the first high-entropy alloy structure is 1 nm-500 μm.

[0057] Further, each of the carbon nanotubes is completely wrapped by the second high-entropy alloy structure.

[0058] Further, the second high-entropy alloy structure has a tubular shell structure conforming to the carbon nanotube.

[0059] Further, the thickness of the second high-entropy alloy structure is 0.1 nm-500 nm.

[0060] Further, part of the first high-entropy alloy structure is also embedded in the second high-entropy alloy structure.

[0061] Further, the diameter of the carbon nanotube is 0.4-100 nm.

[0062] Another aspect of the present application also provides an electrode formed by the high-entropy alloy / carbon nanotube composite material with multiple micro-nano structures or the preparation method of the high-entropy alloy / carbon nanotube composite material with multiple micro-nano structures.

[0063] Further, the electrode can be an electrode for electrolysis of water to produce hydrogen and oxygen, an electrode for reduction of carbon dioxide, or an electrode of a lithium battery.

[0064] Compared with the prior art, the advantages of the present application include: the present application improves the wettability between the high-entropy alloy and the carbon nanotube by using a metal infiltrated with the carbon nanotube, so that the high-entropy alloy / carbon nanotube core-sheath structure can be formed; through the design of the transient ultrahigh temperature heating process, two-step heating is introduced, and the high-entropy alloy nanosphere and the high-entropy alloy / carbon nanotube core-sheath structure are grown step by step, so that the high-entropy alloy / carbon nanotube composite self-supporting electrode material with both nanosphere and core-sheath structure is constructed, the catalytic activity is improved, and the application requirements in the field of high-performance catalysis and battery electrodes are met. BRIEF DESCRIPTION OF DRAWINGS

[0065] Figure 1 is an electron microscope image of the high-entropy alloy / carbon nanotube composite material with multiple micro-nano structures obtained in Example 1 of the present application;

[0066] Figure 2 is an electron microscope image of the high-entropy alloy / carbon nanotube composite material obtained in Example 2 of the present application;

[0067] Figure 3 is an electron microscope image of the high-entropy alloy / carbon nanotube composite material obtained in Example 3 of the present application;

[0068] Figure 4 is the electrolytic water hydrogen production stability of the high-entropy alloy / carbon nanotube composite material with multiple micro-nano structures obtained in Example 1 compared with an iridium oxide||platinum carbon (IrO2||Pt / C) electrode. DETAILED DESCRIPTION

[0069] In view of the deficiencies in the prior art, the present inventors have long studied and practiced to come up with the technical solution of the present application. The technical solution, its implementation process and principles will be further explained in combination with the drawings and specific implementation cases as follows.

[0070] Due to the influence of the wettability of carbon nanotubes and high-entropy alloys and the preparation process, there is currently no highly effective method to tightly combine any high-entropy alloy with carbon nanotubes, so that the high-entropy alloy is coated on the surface of the carbon nanotubes to form a high-entropy alloy / carbon nanotube core-sheath structure, and a self-supporting high-entropy alloy / carbon nanotube composite electrode material with both nanospheres and core-sheath structure is constructed. The present application introduces metal elements that wet carbon nanotubes to improve the wettability between high-entropy alloys and carbon nanotubes, thereby improving the wettability problem of high-entropy alloys and carbon nanotubes

[0071] The present application forms a high-entropy alloy / carbon nanotube core-sheath structure by controlling the transient ultra-high temperature heating temperature, first growing high-entropy alloy microspheres of micro-nano size at a relatively high temperature, and then growing a high-entropy alloy shell structure wrapping the carbon nanotubes at a lower temperature, and the present application also improves the wettability of high-entropy alloy / carbon nanotubes, thereby successfully constructing an electrode material with both core-sheath and microsphere multiple micro-nano structures.

[0072] In a more typical embodiment, a method for preparing a high-entropy alloy / carbon nanotube composite material with multiple micro-nano structures comprises the following steps:

[0073] 1) Dissolve selected metal salts and / or organometallic compounds (i.e. the aforementioned first / second high-entropy alloy precursors, the same below) in an organic solvent that wets carbon nanotubes to form a mixed solution (i.e. the aforementioned first / second high-entropy alloy precursor solution, the same below), the concentration of which can be adjusted according to requirements. For example, the concentration of metal salts and / or organometallic compounds in the mixed solution can be from 0.01 mol / L to a saturated solution.

[0074] It should be noted that the type of metal element contained in the metal salt and / or organometallic compound is selected according to the design or actual demand, and the metal element contained in the metal salt and / or organometallic compound can at least form the designed high-entropy alloy. If the designed high-entropy alloy does not contain a metal element that can infiltrate the carbon nanotube, a metal element (i.e., the selected metal element described above) that can well infiltrate the carbon nanotube, such as nickel, is added, and a metal salt (e.g., nickel chloride) or an organometallic compound (e.g., nickel acetylacetone) of the metal element is dissolved in an organic solvent (e.g., ethanol) together with metal salts or organometallic compounds containing other metal components (components for forming the high-entropy alloy) to form a mixed solution with a low concentration. If the designed or required high-entropy alloy already contains a metal element that can infiltrate the carbon nanotube, no additional addition is required.

[0075] 2) The mixed solution obtained in step 1) is uniformly dropped on the carbon nanotube film or carbon nanotube fiber, or the carbon nanotube film / carbon nanotube fiber is immersed in the mixed solution obtained in step 1), and then dried to allow the metal salt and / or organometallic compound in the mixed solution to be uniformly loaded in the carbon nanotube film or carbon nanotube fiber.

[0076] 3) The carbon nanotube fiber or carbon nanotube film loaded with the metal salt and / or organometallic compound obtained in step 2) is loaded into a transient ultra-high temperature heating device, and the two ends of the carbon nanotube fiber or carbon nanotube film are connected to an electric circuit.

[0077] 4) The reaction zone of the transient ultra-high temperature heating device is evacuated and then filled with argon to standard atmospheric pressure, and the process of evacuation and argon filling is repeated three times to completely remove oxygen and water in the reaction zone, and then argon is continuously filled at a constant rate to build an inert gas environment required for the reaction.

[0078] 5) A first high-power pulse current is passed through the carbon nanotube film / carbon nanotube fiber loaded with the metal salt and / or metal organometallic compound obtained in step 2) by using a high-power pulse power supply, the first high-power pulse current is 1-1000 A (the larger the size of the carbon nanotube, the greater the required current, and the first high-power pulse current can also exceed 1000 A), the duty cycle of the first pulse current is 10-90%, the frequency of the first pulse current is 0.1-1000 Hz, and the total duration of the first pulse current is 1 ms-1 min, so that the carbon nanotube film / carbon nanotube fiber generates a transient ultra-high temperature of 1000-3000 K to promote the decomposition of the metal salt and / or metal organometallic compound on the surface of the carbon nanotube, and multiple metals are melted by relying on the rapid temperature rise and fall (transient ultra-high temperature) to form high-entropy alloy microspheres with micro-nano size distributed on the surface of the carbon nanotube (i.e., the first high-entropy alloy structure described above, the same below).

[0079] 6) Subsequently, the mixed solution obtained in step 1) is again uniformly dropped on the carbon nanotube film or carbon nanotube fiber on which high-entropy nanospheres have been grown, or the carbon nanotube film / carbon nanotube fiber is immersed in the above mixed solution, and then dried, so that the metal salt and / or organic metal compound is again uniformly loaded in the carbon nanotube film or carbon nanotube fiber.

[0080] 7) A second high-power pulse current is passed through the carbon nanotube film / fiber loaded with the metal salt and / or metal organic compound obtained in step 6) by using a high-power pulse power supply, the second high-power pulse current being 0.5-800 A, the frequency of the second pulse current being 0-0.1 Hz, the duty cycle of the second pulse current being 10-90%, and the total duration of the second pulse current being 100 ms-10 min, so that a transient super-high temperature of 800-1500 K is generated in the carbon nanotube film / fiber, the metal salt and / or metal organic compound is decomposed, and a plurality of metals is smelted by means of rapid temperature rise and fall (transient super-high temperature) to form a high-entropy alloy wrapping the carbon nanotube and further forming a high-entropy alloy / carbon nanotube core-sheath structure; it should be noted that the size of the second high-power pulse current is significantly lower than that of the first high-power pulse current, so as to reduce the peak temperature of the transient super-high temperature heating, thereby facilitating the formation of the high-entropy alloy / carbon nanotube core-sheath structure, i.e., the transient super-high temperature in this step is lower than that in step 5), specifically, the temperature of the carbon nanotube film / fiber in step 7) is more than 20% lower than that of the carbon nanotube film / fiber in step 5), so as to avoid the melting of the formed microsphere structure and excessive reaction with the subsequent precursor, thereby damaging the microsphere structure, and specifically, the temperature of the carbon nanotube film / fiber in step 7) is 50-80% of the temperature of the carbon nanotube film / fiber in step 5).

[0081] It should be noted that the size, frequency, duty cycle and total duration of the high-power pulse current used in the two transient super-high temperature heating processes are adjusted respectively to control the temperature, thermal shock time, heating interval and total heating time of the transient super-high temperature, and further control the morphology, size and structure of the prepared high-entropy alloy microspheres and high-entropy alloy / carbon nanotube core-sheath structure. The micro / nano-scale morphology, size and structure of the formed high-entropy nanoscale alloy are established by electron microscopy characterization, and the structure-activity relationship between the above temperature program is established, and a controllable preparation method of the high-entropy alloy / carbon nanotube composite electrode material with microsphere structure and core-sheath structure is established. In addition, for different application requirements, the composition and structure of the high-entropy alloy are designed, the transient super-high temperature heating preparation process is determined according to the above established structure-activity relationship, and thus the high-entropy alloy / carbon nanotube composite electrode material is customized and prepared.

[0082] Example 1

[0083] A preparation method of a Fe-Co-Ni-V-S high-entropy alloy / carbon nanotube composite electrode material with multiple micro-nano structures, comprising the following steps:

[0084] 1) Dissolve iron chloride, cobalt chloride, nickel chloride and vanadium chloride into ethanol to configure a mixed solution with a concentration of 0.1 mol / L for each salt, wherein iron, cobalt and nickel all have good wettability with carbon nanotubes, and no other metal elements that can wet carbon nanotubes are needed to be added;

[0085] 2) Soak a carbon nanotube film (5 cm*0.5 cm*10 μm) in the mixed solution obtained in step 1) for 1 minute, and then take it out and dry it in air;

[0086] 3) Put the carbon nanotube film loaded with multiple metal salts into a transient ultra-high temperature heating device, connect the electrodes at both ends of the carbon nanotube film to the pulse power supply, perform vacuum-argon treatment on the growth area of the transient ultra-high temperature heating device for three times to remove oxygen in the growth area of the transient ultra-high temperature heating device, and then introduce carbon disulfide (CS2) into the growth area by means of argon bubbling;

[0087] 4) Turn on the pulse power switch, set the pulse voltage to 75 V, the frequency to 20 Hz, the duty cycle to 50%, and the duration to 1 minute, so that a transient ultra-high temperature of about 2000 K is generated in the carbon nanotube film, and thus nanoscale Fe-Co-Ni-V-S high-entropy alloy microspheres are formed on the surface of the carbon nanotubes in the carbon nanotube film;

[0088] 5) Soak the carbon nanotube film with the grown Fe-Co-Ni-V-S high-entropy alloy microspheres into the mixed solution obtained in step 1) again for 1 minute, take it out, and dry it in air;

[0089] 6) Put the carbon nanotube film obtained in step 5) into the transient ultra-high temperature heating device again, connect the electrodes at both ends of the carbon nanotube film to the pulse power supply, perform vacuum-argon treatment on the growth area of the transient ultra-high temperature heating device for three times to remove oxygen, and then introduce carbon disulfide (CS2) into the growth area by means of argon bubbling;

[0090] 7) Turn on the pulse power switch, pulse pressurize the carbon nanotube film, set the pulse voltage to 50 V, the frequency to 0.1 Hz, the duty cycle to 50%, and the duration to 1 minute, so that a transient ultra-high temperature of 1200 K is generated in the carbon nanotube film, and Fe-Co-Ni-V-S high-entropy alloy wrapping the carbon nanotubes is formed on the surface of the carbon nanotubes; after two high-low temperature heating growth processes, a Fe-Co-Ni-V-S high-entropy alloy / carbon nanotube composite electrode material with both high-entropy alloy microspheres and core-sheath structures is finally prepared, as shown in Figure 1 , and the Figure 1It can be seen that the iron-cobalt-nickel-vanadium-sulfur high-entropy alloy / carbon nanotube core-sheath structure as a whole is in the form of fibers, the thickness of the iron-cobalt-nickel-vanadium-sulfur high-entropy alloy sheath layer is below 100 nm, and meanwhile, the iron-cobalt-nickel-vanadium-sulfur high-entropy alloy / carbon nanotube composite material has a microsphere structure, and the diameter of the microsphere structure is 0.1-1.5 μm.

[0091] The high-entropy alloy / carbon nanotube composite material with the multiple micro-nano structures prepared in Example 1 was applied as an electrode to electrolytic water to produce hydrogen, and the stability of the high-entropy alloy / carbon nanotube composite material with the multiple micro-nano structures obtained in Example 1 in electrolytic water to produce hydrogen was compared with that of IrO2||Pt / C in electrolytic water to produce hydrogen, and the comparison results are shown in Figure 4 It can be seen that the iron-cobalt-nickel-vanadium-sulfur high-entropy alloy / carbon nanotube composite material obtained in Example 1 has the same catalytic performance as the traditional noble metal-based electrode material IrO2||Pt / C, and the stability thereof is far higher than that of the noble metal catalyst electrode, and the current density of the iron-cobalt-nickel-vanadium-sulfur high-entropy alloy / carbon nanotube electrode can be stably maintained at 8.5 mA cm -2 above, while the performance of the IrO2||Pt / C electrode is continuously reduced.

[0092] Example 2

[0093] A preparation method of an iron-cobalt-nickel-vanadium-sulfur high-entropy alloy / carbon nanotube composite electrode material with multiple micro-nano structures, comprising the following steps:

[0094] 1) FeCl3, CoCl2, NiCl2 and VCl3 were dissolved in ethanol to prepare a mixed solution with the concentration of each salt being 0.1 mol / L, wherein Fe, Co and Ni all have good wettability with carbon nanotubes, and no other metal elements which can wet carbon nanotubes are needed to be added;

[0095] 2) A carbon nanotube film (5 cm x 0.5 cm x 10 μm) was immersed in the mixed solution obtained in step 1) for 1 minute and then taken out and dried in air;

[0096] 3) The carbon nanotube film loaded with the multiple metal salts was loaded into a transient ultrahigh-temperature heating device, the two ends of the carbon nanotube film were connected to the electrodes of a pulse power supply, the growth area of the transient ultrahigh-temperature heating device was treated by vacuumization-argon gas circulation three times to remove oxygen in the growth area of the transient ultrahigh-temperature heating device, and then carbon disulfide (CS2) was introduced into the growth area by means of argon gas bubbling;

[0097] 4) The pulse power supply switch was turned on, and the pulse voltage was set to 120 V, the frequency was set to 20 Hz, the duty cycle was set to 50%, and the duration was set to 1 minute, so that the transient ultrahigh-temperature of about 3000 K was generated in the carbon nanotube film, and the nanoscale iron-cobalt-nickel-vanadium-sulfur high-entropy alloy microspheres were formed on the surface of the carbon nanotubes in the carbon nanotube film;

[0098] 5) The carbon nanotube film grown with iron-cobalt-nickel-vanadium-sulfur high-entropy alloy microspheres is immersed again in the mixed solution obtained in step 1), and taken out after soaking for 1 minute and air-dried;

[0099] 6) The carbon nanotube film obtained in step 5) is loaded again into the transient ultrahigh-temperature heating device, and the electrodes at both ends of the carbon nanotube film are connected to the electrodes of the pulse power supply. The growth area of the transient ultrahigh-temperature heating device is treated by vacuuming and argon blowing three times to exclude oxygen, and then carbon disulfide (CS2) is introduced into the growth area by argon bubbling;

[0100] 7) The pulse power supply switch is turned on to pulse pressurize the carbon nanotube film, and the pulse voltage is set to 60 V, the frequency is 0.1 Hz, the duty cycle is 50%, and the duration is 1 minute, so that the transient ultrahigh temperature of 1500 K is generated in the carbon nanotube film, and the iron-cobalt-nickel-vanadium-sulfur high-entropy alloy wrapped around the carbon nanotube is formed on the surface of the carbon nanotube. After two high and low temperature heating and growth, an iron-cobalt-nickel-vanadium-sulfur high-entropy alloy / carbon nanotube composite electrode material with high-entropy alloy microspheres and core-sheath structure is finally prepared.

[0101] As shown in Figure 2 The product obtained in the embodiment has a microsphere structure with a diameter of 0.1-1.5 μm, and has an iron-cobalt-nickel-vanadium-sulfur high-entropy alloy / carbon nanotube core-sheath structure, and the whole is in a fibrous shape. The thickness of the iron-cobalt-nickel-vanadium-sulfur high-entropy alloy sheath layer is below 100 nm, forming the high-entropy alloy / carbon nanotube composite material with multiple micro-nano structures.

[0102] Example 3

[0103] A method for preparing an iron-cobalt-nickel-vanadium-sulfur high-entropy alloy / carbon nanotube composite electrode material with multiple micro-nano structures, comprising the following steps:

[0104] 1) Iron chloride, cobalt chloride, nickel chloride, and vanadium chloride are dissolved in ethanol to prepare a mixed solution with a concentration of 0.1 mol / L for each salt. Iron, cobalt, and nickel have good wettability with carbon nanotubes, and no other metal elements that can wet carbon nanotubes need to be added;

[0105] 2) A carbon nanotube film (5 cm x 0.5 cm x 10 μm) is immersed in the mixed solution obtained in step 1), and taken out after soaking for 1 minute and air-dried;

[0106] 3) Put the carbon nanotube film loaded with multiple metal salts into a transient ultrahigh temperature heating device, connect the electrodes at both ends of the carbon nanotube film to the pulse power supply, and perform vacuum-argon treatment on the growth area of the transient ultrahigh temperature heating device for three times to remove oxygen in the growth area of the transient ultrahigh temperature heating device, and then introduce carbon disulfide (CS2) into the growth area by argon bubbling;

[0107] 4) Turn on the pulse power switch, set the pulse voltage to 35V, the frequency to 200Hz, the duty cycle to 50%, and the duration to 1 minute, so that a transient ultrahigh temperature of about 1000K is generated in the carbon nanotube film, thereby forming nanoscale iron-cobalt-nickel-vanadium-sulfur high-entropy alloy microspheres on the surface of the carbon nanotubes in the carbon nanotube film;

[0108] 5) Re-dip the carbon nanotube film grown with iron-cobalt-nickel-vanadium-sulfur high-entropy alloy microspheres into the mixed solution obtained in step 1), soak for 1 minute, and then take out and dry in air;

[0109] 6) Put the carbon nanotube film obtained in step 5) into the transient ultrahigh temperature heating device again, connect the electrodes at both ends of the carbon nanotube film to the pulse power supply, and perform vacuum-argon treatment on the growth area of the transient ultrahigh temperature heating device for three times to remove oxygen, and then introduce carbon disulfide (CS2) into the growth area by argon bubbling;

[0110] 7) Turn on the pulse power switch, pulse the carbon nanotube film, set the pulse voltage to 28V, the frequency to 0.08Hz, the duty cycle to 50%, and the duration to 1 minute, so that a transient ultrahigh temperature of 800K is generated in the carbon nanotube film, and iron-cobalt-nickel-vanadium-sulfur high-entropy alloy wrapped around the carbon nanotubes is formed on the surface of the carbon nanotubes. After two high and low temperature heating growth, an iron-cobalt-nickel-vanadium-sulfur high-entropy alloy / carbon nanotube composite electrode material with both high-entropy alloy microspheres and core-sheath structure is finally prepared.

[0111] Example 4

[0112] A method for preparing an iron-cobalt-nickel-vanadium-sulfur high-entropy alloy / carbon nanotube composite electrode material with multiple micro-nano structures, comprising the following steps:

[0113] 1) Dissolve iron chloride, cobalt chloride, nickel chloride, and vanadium chloride in ethanol to prepare a mixed solution with a concentration of 0.1 mol / L for each salt. Iron, cobalt, and nickel have good wettability with carbon nanotubes, and no additional metal elements that can wet carbon nanotubes are needed.

[0114] 2) Dip a carbon nanotube film (5cm x 0.5cm x 10μm) into the mixed solution obtained in step 1), soak for 1 minute, and then take out and dry in air;

[0115] 3) Put the carbon nanotube film loaded with multiple metal salts into a transient ultrahigh temperature heating device, connect the electrodes at both ends of the carbon nanotube film to the pulse power supply, and perform vacuum-argon treatment on the growth area of the transient ultrahigh temperature heating device three times to remove oxygen in the growth area of the transient ultrahigh temperature heating device, and then introduce carbon disulfide (CS2) into the growth area by argon bubbling;

[0116] 4) Turn on the pulse power switch, set the pulse voltage to 75V, the frequency to 1000Hz, the duty cycle to 50%, and the duration to 1 minute, so that a transient ultrahigh temperature of about 2000K is generated in the carbon nanotube film, thereby forming nanoscale iron-cobalt-nickel-vanadium-sulfur high-entropy alloy microspheres on the surface of the carbon nanotubes in the carbon nanotube film;

[0117] 5) Re-dip the carbon nanotube film grown with iron-cobalt-nickel-vanadium-sulfur high-entropy alloy microspheres into the mixed solution obtained in step 1), soak for 1 minute, and then take it out and dry in the air;

[0118] 6) Put the carbon nanotube film obtained in step 5) into the transient ultrahigh temperature heating device again, connect the electrodes at both ends of the carbon nanotube film to the pulse power supply, and perform vacuum-argon treatment on the growth area of the transient ultrahigh temperature heating device three times to remove oxygen, and then introduce carbon disulfide (CS2) into the growth area by argon bubbling;

[0119] 7) Turn on the pulse power switch, pulse the carbon nanotube film, set the pulse voltage to 50V, the frequency to 0.01Hz, the duty cycle to 50%, and the duration to 1 minute, so that a transient ultrahigh temperature of 1200K is generated in the carbon nanotube film, and an iron-cobalt-nickel-vanadium-sulfur high-entropy alloy wrapped around the carbon nanotube is formed on the surface of the carbon nanotube; after two high and low temperature heating and growth, an iron-cobalt-nickel-vanadium-sulfur high-entropy alloy / carbon nanotube composite electrode material with both high-entropy alloy microspheres and core-sheath structure is finally prepared.

[0120] Comparative Example 1

[0121] A method for preparing an iron-cobalt-nickel-vanadium-sulfur high-entropy alloy / carbon nanotube composite electrode material with multiple micro-nano structures, comprising the following steps:

[0122] 1) Dissolve iron chloride, cobalt chloride, nickel chloride, and vanadium chloride in ethanol to prepare a mixed solution with a concentration of 0.1 mol / L for each salt, wherein iron, cobalt, and nickel have good wettability with carbon nanotubes without the need to add other metal elements that can wet carbon nanotubes;

[0123] 2) Dip a carbon nanotube film (5cm×0.5cm×10μm) into the mixed solution obtained in step 1), soak for 1 minute, and then take it out and dry in the air;

[0124] 3) The carbon nanotube film loaded with various metal salts was loaded into a transient ultra-high temperature heating device. The two ends of the carbon nanotube film were connected to the electrodes of the pulse power supply. The growth area of ​​the transient ultra-high temperature heating device was evacuated and purged with argon gas. This process was repeated three times to remove oxygen from the growth area of ​​the transient ultra-high temperature heating device. Then, carbon disulfide (CS2) was introduced into the growth area by argon gas bubbling.

[0125] 4) Turn on the pulse power switch, set the pulse voltage to 150V, frequency to 20Hz, duty cycle to 50%, and duration to 1 minute, so as to generate a transient ultra-high temperature of over 3500K in the carbon nanotube film.

[0126] 5) Immerse the carbon nanotube film obtained in step 4) again in the mixed solution obtained in step 1), soak for 1 minute, then remove and air dry.

[0127] 6) The carbon nanotube film obtained in step 5) is put back into the transient ultra-high temperature heating device. The two ends of the carbon nanotube film are connected to the electrodes of the pulse power supply. The growth area of ​​the transient ultra-high temperature heating device is evacuated and purged with argon gas. This process is repeated three times to remove oxygen. Then, carbon disulfide (CS2) is introduced into the growth area by argon gas bubbling.

[0128] 7) Turn on the pulse power switch to apply pulse pressure to the carbon nanotube film. Set the pulse voltage to 120V, frequency to 20Hz, duty cycle to 50%, and duration to 1 minute to generate a transient ultra-high temperature of about 3000K in the carbon nanotube film.

[0129] Observations revealed that due to the excessively high temperatures during the two transient ultra-high temperature trials, the final prepared iron-cobalt-nickel-vanadium-sulfur high-entropy alloy / carbon nanotube composite electrode material only formed high-entropy alloy microspheres after two high-temperature heating growth processes. Figure 3 As shown, with two heating cycles at high temperatures, only a large number of large-sized high-entropy alloy particles with a size of 1-10 μm were formed on the surface of the carbon nanotube film, while no iron-cobalt-nickel-vanadium-sulfur high-entropy alloy / carbon nanotube core-sheath structure was observed.

[0130] Comparative Example 2

[0131] A method for preparing a high-entropy iron-cobalt-nickel-vanadium-sulfur composite electrode material with multiple micro / nano structures includes the following steps:

[0132] 1) Dissolve ferric chloride, cobalt chloride, nickel chloride and vanadium chloride in ethanol to prepare a mixed solution with a concentration of 0.1 mol / L for each salt. Iron, cobalt and nickel have good wettability with carbon nanotubes, so there is no need to add other metal elements that wet carbon nanotubes.

[0133] 2) carbon nanotube film (5 cm x 0.5 cm x 10 μm) is immersed in the mixed solution obtained in step 1) for 1 minute, and then taken out and dried in air;

[0134] 3) the carbon nanotube film loaded with multiple metal salts is loaded into a transient ultra-high temperature heating device, the two ends of the carbon nanotube film are connected to the electrodes of a pulse power supply, the growth area of the transient ultra-high temperature heating device is subjected to vacuum-argon treatment for three times to remove oxygen in the growth area of the transient ultra-high temperature heating device, and then carbon disulfide (CS2) is introduced into the growth area by argon bubbling;

[0135] 4) the pulse power supply switch is turned on, the pulse voltage is set to 25 V, the frequency is set to 2000 Hz, the duty cycle is set to 50%, and the duration is set to 1 minute, so that a transient high temperature of about 750 K is generated in the carbon nanotube film;

[0136] 5) the carbon nanotube film obtained in step 4) is again immersed in the mixed solution obtained in step 1), soaked for 1 minute, and then taken out and dried in air;

[0137] 6) the carbon nanotube film obtained in step 5) is again loaded into a transient ultra-high temperature heating device, the two ends of the carbon nanotube film are connected to the electrodes of a pulse power supply, the growth area of the transient ultra-high temperature heating device is subjected to vacuum-argon treatment for three times to remove oxygen, and then carbon disulfide (CS2) is introduced into the growth area by argon bubbling;

[0138] 7) the pulse power supply switch is turned on, the pulse voltage is set to 20 V, the frequency is set to 20 Hz, the duty cycle is set to 50%, and the duration is set to 1 minute, so that a transient high temperature of about 600 K is generated in the carbon nanotube film.

[0139] It is observed that the two heating temperatures are low, the amount of precursor volatilization is small, the carbon nanotube film surface has a large number of large-size high-entropy alloy particles with a size of 1-10 μm, and no iron-cobalt-nickel-vanadium-sulfur high-entropy alloy / carbon nanotube core-sheath structure is observed.

[0140] Comparative Example 3

[0141] A preparation method of an iron-cobalt-nickel-vanadium-sulfur high-entropy alloy / carbon nanotube composite electrode material with multiple micro-nano structures, comprising the following steps:

[0142] 1) iron chloride, cobalt chloride, nickel chloride, and vanadium chloride are dissolved in ethanol to prepare a mixed solution with a concentration of 0.1 mol / L for each salt, wherein iron, cobalt, and nickel have good wettability with carbon nanotubes, and no other metal elements that can wet carbon nanotubes need to be added;

[0143] 2) carbon nanotube film (5cm*0.5cm*10um) is immersed in the mixed solution obtained in step 1), taken out after soaking for 1 minute, and dried in air;

[0144] 3) the carbon nanotube film loaded with multiple metal salts is loaded into a transient ultra-high temperature heating device, the electrodes at both ends of the carbon nanotube film are connected to the electrodes of a pulse power supply, the growth area of the transient ultra-high temperature heating device is subjected to vacuum-argon treatment, and the process is repeated three times to remove oxygen in the growth area of the transient ultra-high temperature heating device, and then carbon disulfide (CS2) is introduced into the growth area by argon bubbling;

[0145] 4) the pulse power supply switch is turned on, the pulse voltage is set to 75V, the frequency is set to 0.05Hz, the duty cycle is set to 50%, and the duration is set to 1 minute, so that a transient ultra-high temperature of about 2000K is generated in the carbon nanotube film;

[0146] 5) the carbon nanotube film obtained in step 4) is again immersed in the mixed solution obtained in step 1), taken out after soaking for 1 minute, and dried in air;

[0147] 6) the carbon nanotube film obtained in step 5) is again loaded into a transient ultra-high temperature heating device, the electrodes at both ends of the carbon nanotube film are connected to the electrodes of a pulse power supply, the growth area of the transient ultra-high temperature heating device is subjected to vacuum-argon treatment, and the process is repeated three times to remove oxygen, and then carbon disulfide (CS2) is introduced into the growth area by argon bubbling;

[0148] 7) the pulse power supply switch is turned on, the pulse voltage is set to 50V, the frequency is set to 20Hz, the duty cycle is set to 50%, and the duration is set to 1 minute, so that a transient ultra-high temperature of about 1200K is generated in the carbon nanotube film.

[0149] It is observed that the frequency of generating transient ultra-high temperature does not affect the product, and the product cannot form small-scale high-entropy microspheres and core-sheath structures, and the product is irregular, large-particle, and multi-phase separated alloy.

[0150] The present application realizes the preparation of high-entropy alloy / carbon nanotube composite electrode material with nano microsphere structure and core-sheath structure by introducing metal elements infiltrated into carbon nanotube and adopting two-step transient ultra-high temperature heating and step-by-step preparation, and realizes the control of the morphology, size and structure of high-entropy alloy nano microspheres and high-entropy alloy / carbon nanotube core-sheath structure by establishing the structure-activity relationship between the transient ultra-high temperature heating program and the product morphology, size and structure, and realizing controllable preparation.

[0151] The application improves the wettability between the high-entropy alloy and the carbon nanotube by using the metal infiltrated with the carbon nanotube, so that the high-entropy alloy / carbon nanotube core-sheath structure can be formed; through the design of the transient ultrahigh temperature heating program, two-step heating is introduced, and the high-entropy alloy nanometer microspheres and the high-entropy alloy / carbon nanotube core-sheath structure are grown step by step, so that the high-entropy alloy / carbon nanotube composite self-supporting electrode material with the nanometer microspheres and the core-sheath structure is constructed, the conductivity and the catalytic activity are improved, and the application requirements in the high-performance catalysis and the battery electrode field are met.

[0152] The microspheres (i.e., the first high-entropy alloy structure in the form of microspheres) and the core-sheath structure (i.e., the second high-entropy alloy structure in the form of the core-sheath structure) in the high-entropy alloy / carbon nanotube composite material with the multiple micro-nano structures provided by the application interact with each other, if only the high-entropy microspheres, the current needs to be conducted between the microspheres through the carbon nanotube, and the conductivity of the carbon nanotube is relatively low, so that the charge transmission between the microspheres is limited, and when the core-sheath structure is introduced at the same time, the microspheres can not only transmit the charge through the carbon nanotube, but also be connected and transmit the charge through the core-sheath structure, so that the catalytic reaction efficiency is improved; meanwhile, the catalytic activity of the core-sheath structure itself is also high, the conductivity between the microspheres is filled, the active sites are increased, and the catalytic activity of the composite material and the electrode is further improved; in addition, the carbon nanotube, the high-entropy alloy nanometer microspheres and the core-sheath structure form a unified whole, have high mechanical strength, and combine to form the self-supporting electrode with high catalytic activity.

[0153] The high-entropy alloy / carbon nanotube composite material with the multiple micro-nano structures provided by the application has higher conductivity, the carbon nanotube matrix forms a conductive network, the core-sheath structure is coated on the carbon nanotube, and the conductivity is further improved; compared with the pure high-entropy microsphere powder, the conductivity of the high-entropy alloy / carbon nanotube composite material with the multiple micro-nano structures provided by the application is greatly improved, and the conductivity is also advantageous compared with the carbon nanotube / high-entropy microsphere structure; the high-entropy alloy / carbon nanotube composite material with the multiple micro-nano structures provided by the application has high catalytic activity, through the regulation of element ratio, the catalytic activity of the high-entropy alloy formed by the mixing of multiple metals is higher than that of a single metal, and the activity can even be superior to that of a noble metal catalyst (such as platinum), and in addition, the multiple structures increase the active sites, and the catalytic activity is further improved.

[0154] The high-entropy alloy / carbon nanotube composite material with the multiple micro-nano structures provided by the application can form the high-entropy alloy by using cheap metals, and improve the activity, so that the electrode cost is reduced.

[0155] It should be understood that the above embodiments are only for illustrating the technical concept and characteristics of the application, and the purpose is to enable those skilled in the art to understand the content of the application and implement it, and cannot limit the protection scope of the application. Any equivalent changes or modifications made according to the spirit and principle of the application should be covered within the protection scope of the application.

Claims

1. A method for preparing a high-entropy alloy / carbon nanotube composite material with multiple micro / nano structures, characterized in that, include: A first high-entropy alloy precursor is formed on the surface of carbon nanotubes; The temperature of the first high-entropy alloy precursor is transiently heated to a first temperature to transform the first high-entropy alloy precursor into a first high-entropy alloy structure, wherein the first high-entropy alloy structure is distributed at intervals on the surface of the carbon nanotubes. A second high-entropy alloy precursor is formed on the surface of the carbon nanotubes; The second high-entropy alloy precursor is transiently heated to a second temperature, which is lower than the first temperature, to transform the second high-entropy alloy precursor into a second high-entropy alloy structure. The second high-entropy alloy structure coats the carbon nanotubes and forms a high-entropy alloy / carbon nanotube core-sheath structure with the carbon nanotubes.

2. The preparation method according to claim 1, characterized in that, Specifically, it includes: A first pulse current is passed into the carbon nanotube, and the first high-entropy alloy precursor is transiently heated to a first temperature by the self-heating of the carbon nanotube under the Joule heating effect.

3. The preparation method according to claim 2, characterized in that: The magnitude of the first pulse current is 1-1000A.

4. The preparation method according to claim 2, characterized in that: The frequency of the first pulse current is 1-1000Hz.

5. The preparation method according to claim 2, characterized in that: The duty cycle of the first pulse current is 10-90%.

6. The preparation method according to claim 2, characterized in that: The total duration of the first pulse current is 1 ms to 1 min.

7. The preparation method according to claim 1 or 2, characterized in that, The preparation method specifically includes: passing a second pulse current into the carbon nanotube, thereby transiently heating the second high-entropy alloy precursor to a second temperature through the self-heating of the carbon nanotube under the Joule heating effect.

8. The preparation method according to claim 7, characterized in that: The magnitude of the second pulse current is 0.5-800A.

9. The preparation method according to claim 7, characterized in that: The frequency of the second pulse current is 0-0.1Hz.

10. The preparation method according to claim 7, characterized in that: The duty cycle of the second pulse current is 10-90%.

11. The preparation method according to claim 7, characterized in that: The total duration of the second pulse current is 100 ms to 10 min.

12. The preparation method according to claim 1 or 2, characterized in that, The preparation method specifically includes: transiently heating the first high-entropy alloy precursor to a first temperature in an inert environment.

13. The preparation method according to claim 7, characterized in that, The preparation method specifically includes: transiently heating the second high-entropy alloy precursor to a second temperature in an inert environment.

14. The preparation method according to claim 1, characterized in that: The first temperature is 1000-3000 K.

15. The preparation method according to claim 1, characterized in that: The second temperature is 800-2400 K.

16. The preparation method according to claim 1, characterized in that, Specifically, it includes: The first high-entropy alloy precursor is mixed with a first solvent to form a first high-entropy alloy precursor solution. The first high-entropy alloy precursor solution is coated on the surface of the carbon nanotube, or the carbon nanotube is immersed in the first high-entropy alloy precursor solution and then removed, thereby loading the first high-entropy alloy precursor onto the surface of the carbon nanotube.

17. The preparation method according to claim 16, characterized in that: The first solvent is an organic solvent that wets carbon nanotubes.

18. The preparation method according to claim 1, characterized in that, The preparation method specifically includes: mixing the second high-entropy alloy precursor with a second solvent to form a second high-entropy alloy precursor solution; coating the second high-entropy alloy precursor solution onto the surface of the carbon nanotube on which the first high-entropy alloy structure is formed; or immersing the carbon nanotube on which the first high-entropy alloy structure is formed into the second high-entropy alloy precursor solution and then removing it, thereby loading the second high-entropy alloy precursor onto the surface of the carbon nanotube.

19. The preparation method according to claim 18, characterized in that: The second solvent is an organic solvent that wets carbon nanotubes.

20. The preparation method according to claim 1, 16, or 18, characterized in that: The first high-entropy alloy precursor and the second high-entropy alloy precursor are mixtures formed from metal salts and / or organometallic compounds, the mixture comprising at least five metal elements, and the mixture containing at least one selected metal element capable of wetting carbon nanotubes.

21. The preparation method according to claim 20, characterized in that: The selected metallic element includes nickel, titanium, chromium, or iron.

22. The preparation method according to claim 20, characterized in that: The first high-entropy alloy precursor and the second high-entropy alloy precursor contain the same, partially the same, or completely different metallic elements.

23. The preparation method according to claim 1, 16, or 18, characterized in that: The first high-entropy alloy structure is distributed at least at the defects on the surface of the carbon nanotubes.

24. The preparation method according to claim 23, characterized in that: The first high-entropy alloy structure is in the form of microspheres.

25. The preparation method according to claim 24, characterized in that: The first high-entropy alloy structure is a microsphere with micro-nano scale.

26. The preparation method according to claim 23, characterized in that: The diameter of the first high-entropy alloy structure is 1 nm-500 μm.

27. The preparation method according to claim 23, characterized in that: Each of the carbon nanotubes is completely encapsulated by a second high-entropy alloy structure.

28. The preparation method according to claim 23, characterized in that: The second high-entropy alloy structure has a tubular shell structure that mimics the shape of the carbon nanotube.

29. The preparation method according to claim 23, characterized in that: The thickness of the second high-entropy alloy structure is 0.1 nm - 500 nm.

30. The preparation method according to claim 23, characterized in that: A portion of the first high-entropy alloy structure is also embedded within the second high-entropy alloy structure.

31. The preparation method according to claim 23, characterized in that: The diameter of the carbon nanotubes is 0.4-100 nm.

32. A high-entropy alloy / carbon nanotube composite material with multiple micro / nano structures, characterized in that, The high-entropy alloy / carbon nanotube composite material with multiple micro-nano structures is prepared by the preparation method of the high-entropy alloy / carbon nanotube composite material with multiple micro-nano structures according to any one of claims 1-31. The high-entropy alloy / carbon nanotube composite material with multiple micro-nano structures includes: a carbon nanotube matrix, a first high-entropy alloy structure and a second high-entropy alloy structure. The carbon nanotube matrix includes at least one carbon nanotube. The first high-entropy alloy structure is distributed at intervals on the surface of the carbon nanotube. The second high-entropy alloy structure covers the carbon nanotube and forms a high-entropy alloy / carbon nanotube core-sheath structure with the carbon nanotube.

33. The high-entropy alloy / carbon nanotube composite material according to claim 32, characterized in that: The first high-entropy alloy structure is distributed at least at the defects on the surface of the carbon nanotubes.

34. The high-entropy alloy / carbon nanotube composite material according to claim 32, characterized in that: The first high-entropy alloy structure is in the form of microspheres.

35. The high-entropy alloy / carbon nanotube composite material according to claim 34, characterized in that: The first high-entropy alloy structure is a microsphere with micro-nano scale.

36. The high-entropy alloy / carbon nanotube composite material according to claim 32, characterized in that: The diameter of the first high-entropy alloy structure is 1 nm-500 μm.

37. The high-entropy alloy / carbon nanotube composite material according to claim 32, characterized in that: The carbon nanotubes are completely encapsulated by a second high-entropy alloy structure.

38. The high-entropy alloy / carbon nanotube composite material according to claim 32 or 37, characterized in that: The second high-entropy alloy structure is a tubular shell structure that encapsulates the carbon nanotubes.

39. The high-entropy alloy / carbon nanotube composite material according to claim 32, characterized in that: The thickness of the second high-entropy alloy structure is 0.1 nm - 500 nm.

40. The high-entropy alloy / carbon nanotube composite material according to claim 32, characterized in that: A portion of the first high-entropy alloy structure is also embedded within the second high-entropy alloy structure.

41. The high-entropy alloy / carbon nanotube composite material according to claim 32, characterized in that: The first high-entropy alloy structure and the second high-entropy alloy structure contain the same, partially the same, or completely different metallic elements.

42. The high-entropy alloy / carbon nanotube composite material according to claim 41, characterized in that: Both the first high-entropy alloy structure and the second high-entropy alloy structure contain at least one selected metal element that can wet carbon nanotubes.

43. The high-entropy alloy / carbon nanotube composite material according to claim 42, characterized in that: The selected metallic element includes nickel, titanium, chromium, or iron.

44. The high-entropy alloy / carbon nanotube composite material according to claim 32, characterized in that: The carbon nanotube matrix includes a carbon nanotube film or carbon nanotube fiber formed from multiple carbon nanotubes.

45. The high-entropy alloy / carbon nanotube composite material according to claim 32, characterized in that: The diameter of the carbon nanotubes is 0.4-100 nm.

46. ​​An electrode, characterized in that, The electrode is formed from a high-entropy alloy / carbon nanotube composite material with multiple micro-nano structures as described in any one of claims 32-45.

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