A flexible carbon cloth / high-entropy carbide ceramic nanowire composite material, a preparation method and application thereof

Abstract

The application discloses a flexible carbon cloth / high-entropy carbide ceramic nanowire composite material and a preparation method and application thereof. The method comprises the following steps: dispersing a high-entropy ceramic precursor, NaF, Ni(NO3)2*6H2O and Fe(NO3)3*9H2O in dimethylbenzene to obtain a mixed solution through stirring; and placing cotton cloth in the mixed solution for impregnation and drying, and then performing vacuum calcination treatment in an inert atmosphere to obtain the flexible carbon cloth / high-entropy carbide ceramic nanowire composite material. The method has the advantages of simple operation, controllable composition, low preparation temperature, short reaction time, and realization of obtaining the high-entropy carbide ceramic nanowire with uniform element distribution and controllable composition on the flexible carbon cloth substrate at a low temperature.

Description

Technical Field

[0001] This invention belongs to the field of ceramic nanowire material development technology, and relates to a flexible carbon cloth / high entropy carbide ceramic nanowire composite material, its preparation method and application. Background Technology

[0002] High-entropy carbide ceramics have attracted widespread attention due to their high melting point, high hardness, wear resistance, high temperature resistance, oxidation resistance, and low thermal conductivity. These properties make them candidate materials for applications in extreme environments, such as high-temperature solar energy absorbers, rocket nozzles and leading edges of hypersonic vehicles, supercapacitors, microwave absorbing materials, and electromagnetic shielding materials.

[0003] Currently, the main methods for preparing high-entropy carbide ceramics include solid-state sintering, magnetron sputtering, electric arc melting, and liquid-phase precursor methods. Reference 1 (First-principles study, fabrication and characterization of (Zr...) 0.25 Nb 0.25 Ti 0.25 V 0.25 High-entropy ceramics[J]. Acta Materialia, 2019, 170: 15-23.) Using ZrC, NbC, TiC and VC as raw materials, high-entropy ceramics were prepared by hot pressing and sintering. 0.25 Nb 0.25 Ti 0.25 V 0.25 The material exhibits excellent mechanical and thermophysical properties, but the above-mentioned process requires a high preparation temperature, reaching up to 2100℃. Reference 2 (Synthesis of single-phase high-entropy carbide powders[J].Scripta Materialia,2019,162:90-93.) describes a two-step synthesis route involving carbothermal reduction and subsequent solid solution formation to prepare a material with finer particle size and lower oxygen content (Ti). 0.2 Nb 0.2 Zr 0.2 Hf 0.2 Ta 0.2C powder. Compared with ceramic bulk and nanoparticles, one-dimensional nanowires often have higher specific surface area and larger aspect ratio, and exhibit superior performance in fields such as nano-strengthening, catalysis, and electromagnetic shielding. However, current research on high-entropy ceramics is mostly focused on micro- and nano-scale ceramic particles, with relatively few reports on the preparation of high-entropy ceramic nanowires. Reference 3 (High-entropy metal carbide nanowires[J].Cell Reports Physical Science,2022,3(4):100839.) used bamboo powder as a carbon source and reacted it with metal oxides with the aid of a catalyst to prepare (Hf 0.25 Ta 0.25 Nb 0.25 Ti 0.25 ( )C nanowires; however, the main elements of ceramics are limited to quaternary elements, and no reports have been made on more multi-element high-entropy ceramic nanowires. Reference 4 (Single-source precursor derived high-entropy metal-carbide nanowires: Microstructure and growth thevolution[J]. Journal of Advanced Ceramics, 2023.) prepared (Ti) nanowires using multi-element ceramic organic precursors as raw materials through high-temperature heat treatment. 0.2 Zr 0.2 Hf 0.2 Nb0 .2 Ta 0.2 This method produces pentagonal high-entropy ceramic nanowires. However, the preparation temperature is relatively high (1650℃), resulting in limited nanowire yield. Furthermore, although a carbon cloth substrate is introduced, the high-entropy ceramic nanowires do not grow on the substrate surface. Growing high-entropy ceramic nanowires on a flexible substrate at low temperatures could broaden the application prospects of high-entropy carbide ceramic nanowires. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention provides a flexible carbon cloth / high-entropy carbide ceramic nanowire composite material, its preparation method, and its application, thereby solving the technical problems of high-entropy carbide ceramic nanowires requiring high preparation temperatures and failing to bond well with flexible substrates in the prior art.

[0005] This invention is achieved through the following technical solution:

[0006] A method for preparing a flexible carbon cloth / high-entropy carbide ceramic nanowire composite material includes the following steps:

[0007] S1: Disperse the high-entropy ceramic precursor with NaF, Ni(NO3)2·6H2O and Fe(NO3)3·9H2O in xylene and stir to obtain a mixed solution;

[0008] S2: After impregnating and drying the cotton cloth in the mixed solution, it is subjected to vacuum calcination under an inert atmosphere to obtain the flexible carbon cloth / high entropy carbide ceramic nanowire composite material.

[0009] Preferably, the high-entropy precursor is a single-source organic precursor composed of at least four metal elements selected from Ti, Nb, Zr, Hf, Ta, Mo, and V.

[0010] Preferably, the mass ratio of the high-entropy ceramic precursor to NaF, Ni(NO3)2 and Fe(NO3)3 is (0.5-1.5):(0.05-0.15):(0.05-0.15):(0.1-0.3).

[0011] Preferably, in step S1, the stirring time is 0.5 to 2 hours.

[0012] Preferably, in step S2, before placing the cotton fabric in the mixed solution, the cotton fabric is pretreated. The pretreatment includes washing the cotton fabric sequentially with deionized water, anhydrous ethanol, and acetone, and then drying it in an oven.

[0013] Preferably, after pretreatment, the drying temperature is 60-100℃ and the drying time is 8-24h.

[0014] Preferably, in step S2, the cotton is immersed in the mixed solution for 5 to 30 minutes, and then dried at a temperature of 60 to 100°C for 5 to 24 hours.

[0015] Preferably, in step S2, during the vacuum calcination process, the vacuum degree is 0.1 to 0.4 Pa, the argon flow rate is 10 to 200 mL / min, the calcination temperature is 1000 to 1200 °C, and the calcination time is 1 to 10 h; during the calcination process, the heating rate is 5 to 20 °C / min.

[0016] A flexible carbon cloth / high-entropy carbide ceramic nanowire composite material was prepared by the method described above.

[0017] The above-mentioned flexible carbon cloth / high-entropy carbide ceramic nanowire composite material has applications in energy storage and conversion, catalysis, electromagnetic shielding, and wave absorption.

[0018] Compared with the prior art, the present invention has the following beneficial technical effects:

[0019] This invention discloses a method for preparing a flexible carbon cloth / high-entropy carbide ceramic nanowire composite material. First, a high-entropy ceramic precursor is dispersed in xylene along with NaF, Ni(NO3)2, and Fe(NO3)3, and stirred to obtain a mixed solution. Then, cotton cloth is impregnated in the mixed solution, dried, and subjected to vacuum calcination under an inert atmosphere to obtain the flexible carbon cloth / high-entropy carbide ceramic nanowire composite material. During calcination, the cotton cloth is carbonized into flexible carbon cloth at high temperature, and the high-entropy carbide ceramic nanowires grow in situ on the carbon fiber surface. In this preparation method, low-cost cotton cloth is used as the carbon source and growth substrate, and a single-source high-entropy ceramic precursor is used as the metal source. High-entropy carbide ceramic nanowires are prepared with the assistance of an Fe-Ni catalyst. The use of a binary catalyst effectively reduces the growth temperature of the high-entropy carbide ceramic nanowires. This method uses cotton cloth as a substrate, which is transformed into flexible carbon cloth after high-temperature treatment, giving the final sample excellent flexibility. Furthermore, the cotton cloth can not only adsorb sufficient precursor solution and metal catalyst, providing raw materials for nanowire growth, but also release carbon-containing small molecules during its own carbonization, serving as a carbon source for the growth of high-entropy carbide ceramic nanowires. Uniform mixing of the reaction source and catalyst, followed by cotton cloth impregnation, ensures a uniform distribution of both on the cotton cloth, creating favorable conditions for the uniform distribution of nanowires. The high-entropy carbide ceramic nanowires prepared by this method are grown in situ on the surface of the flexible carbon cloth substrate. The nanowires have a diameter of approximately 100 nm and a length of 2–8 μm, with uniform distribution of the main metal elements, and their growth follows a gas-liquid-solid growth mechanism. More importantly, the preparation method proposed in this invention can obtain high-entropy carbide nanowires with different metal ratios by changing the high-entropy ceramic precursor source. This invention develops a simple and efficient method for preparing flexible carbon cloth / high-entropy carbide ceramic nanowire composite materials. The method is simple to operate, has controllable composition, low preparation temperature, and short reaction time. It enables the preparation of high-entropy carbide ceramic nanowires with uniform elemental distribution and controllable composition on a flexible carbon cloth substrate at a relatively low temperature, which is of great significance. At the same time, it has the advantages of low equipment requirements and environmental friendliness, making it suitable for large-scale industrial production and with broad application prospects.

[0020] Furthermore, the high-entropy precursor is a single-source organic precursor composed of at least four metal elements selected from Ti, Nb, Zr, Hf, Ta, Mo, and V, which enables the acquisition of high-entropy carbide ceramic nanowires of the desired elements using only one raw material.

[0021] Furthermore, the mass ratio of the high-entropy ceramic precursor to NaF, Ni(NO3)2 and Fe(NO3)3 is (0.5~1.5):(0.05~0.15):(0.05~0.15):(0.1~0.3), which can effectively control the size and microstructure of the high-entropy carbide ceramic nanowires.

[0022] Furthermore, in step S1, the stirring time is 0.5 to 2 hours, which allows the raw materials and catalyst to be fully dissolved in xylene.

[0023] Furthermore, in step S2, before placing the cotton fabric in the mixed solution, the cotton fabric is pretreated. The pretreatment includes washing the cotton fabric sequentially with deionized water, anhydrous ethanol, and acetone, and then drying it in an oven, which makes the cotton fabric clean, dry, and free of contaminants.

[0024] Furthermore, in step S2, the cotton cloth is immersed in the mixed solution for 5 to 30 minutes, which allows the cotton cloth to fully adsorb the reaction source and catalyst.

[0025] Furthermore, in step S2, during the vacuum calcination process, the vacuum degree is 0.1–0.4 Pa, the argon flow rate is 10–200 mL / min, the calcination temperature is 1000–1200 °C, and the calcination time is 1–10 h; during the calcination process, the heating rate is 5–20 °C / min, which allows the raw materials to react fully and obtain high-entropy carbide ceramic nanowires uniformly distributed on the substrate. Attached Figure Description

[0026] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram illustrating the formation process of the flexible carbon cloth / high-entropy carbide ceramic nanowire composite material in this invention;

[0028] Figure 2 The (Hf) material prepared in this invention has (Hf) grown on the surface of a flexible carbon cloth substrate. 0.2 Zr 0.2 Ta 0.2 Nb 0.2 Ti 0.2 Digital photograph of C high-entropy ceramic nanowires;

[0029] Figure 3 The (Hf) prepared for this invention 0.2 Zr 0.2 Ta 0.2 Nb 0.2 Ti 0.2 XRD pattern of high-entropy ceramic nanowires;

[0030] Figure 4 The (Hf) prepared for this invention 0.2 Zr0.2 Ta 0.2 Nb 0.2 Ti 0.2 SEM characterization image of C high-entropy ceramic nanowires;

[0031] Figure 5 The (Hf) prepared for this invention 0.2 Zr 0.2 Ta 0.2 Nb 0.2 Ti 0.2 HAADF image and corresponding EDS surface scan spectrum of high-entropy ceramic nanowires. Detailed Implementation

[0032] To enable those skilled in the art to understand the features and effects of the present invention, the terms and expressions used in the specification and claims are explained and defined in general below. Unless otherwise specified, all technical and scientific terms used herein have the ordinary meaning understood by those skilled in the art regarding the present invention, and in case of conflict, the definitions in this specification shall prevail.

[0033] The theories or mechanisms described and disclosed herein, whether right or wrong, should not in any way limit the scope of the invention, that is, the contents of the invention can be implemented without being limited by any particular theory or mechanism.

[0034] In this document, all features defined by numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are for the sake of brevity and convenience only. Accordingly, descriptions of numerical ranges or percentage ranges should be considered as covering and specifically disclosing all possible sub-ranges and individual numerical values ​​(including integers and fractions) within those ranges.

[0035] In this article, unless otherwise specified, “contains,” “includes,” “containing,” “has,” or similar terms cover the meanings of “composed of” and “mainly composed of,” for example, “A contains a” covers the meanings of “A contains a and others” and “A contains only a.”

[0036] For the sake of brevity, not all possible combinations of the technical features in each implementation scheme or embodiment are described herein. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each implementation scheme or embodiment can be combined arbitrarily, and all possible combinations should be considered within the scope of this specification.

[0037] like Figure 1As shown, this invention discloses the preparation of a flexible carbon cloth / high-entropy carbide ceramic nanowire composite material. After impregnating the cotton cloth with a solution containing a high-entropy precursor and a catalyst, each cotton fiber is loaded with both the precursor and catalyst. Following high-temperature heat treatment, the cotton fibers are carbonized and serve as the carbon source for the reaction. The high-entropy ceramic precursor provides the metal source for preparing high-entropy ceramic carbide nanowires, thereby obtaining high-entropy ceramic carbide nanowires.

[0038] Specifically, this method discloses a preparation method for a flexible carbon cloth / high-entropy carbide ceramic nanowire composite material, comprising the following steps:

[0039] S1: A high-entropy ceramic precursor is dispersed in xylene along with NaF, Ni(NO3)2·6H2O, and Fe(NO3)3·9H2O, wherein the mass ratio of the high-entropy ceramic precursor to NaF, Ni(NO3)2, and Fe(NO3)3 is (0.5–1.5):(0.05–0.15):(0.05–0.15):(0.1–0.3). The mixture is then stirred for 0.5–2 h to obtain a mixed solution. The high-entropy precursor is a single-source organic precursor composed of at least four metal elements selected from Ti, Nb, Zr, Hf, Ta, Mo, and V.

[0040] S2: Clean the cotton cloth (size can be 4×4cm) sequentially with deionized water, anhydrous ethanol, and acetone. 2 The cotton is then placed in an oven and dried at 60–100°C for 8–24 hours. After drying, the cotton is immersed in the mixed solution for 5–30 minutes, then removed and dried again at 60–100°C for 5–24 hours. Vacuum calcination is then performed under an inert atmosphere, with a vacuum degree of 0.1–0.4 Pa, an argon flow rate of 10–200 mL / min, a calcination temperature of 1000–1200°C, and a calcination time of 1–10 hours. During the calcination process, the heating rate is 5–20°C / min, thus obtaining the flexible carbon cloth / high-entropy carbide ceramic nanowire composite material. During calcination, the cotton is placed above an alumina crucible, and then another alumina crucible is placed on top of the cotton. Finally, the alumina crucible is placed in the sintering furnace temperature zone for calcination.

[0041] This invention proposes a method for growing high-entropy carbide ceramic nanowires on a flexible carbon cloth substrate. Using low-cost cotton cloth as the carbon source and growth substrate, and a single-source high-entropy ceramic precursor as the metal source, high-entropy carbide ceramic nanowires are prepared with the assistance of an Fe-Ni catalyst. This method uses cotton cloth as the substrate, which is transformed into flexible carbon cloth after high-temperature treatment, endowing the final sample with excellent flexibility. Furthermore, the cotton cloth can not only adsorb sufficient precursor solution and metal catalyst, providing raw materials for nanowire growth, but also release carbon-containing small molecules during its own carbonization, which can serve as the carbon source for nanowire growth. The high-entropy carbide ceramic nanowires prepared by this method are grown in situ on the surface of a flexible carbon cloth substrate. The nanowires have a diameter of approximately 100 nm and a length of 2–8 μm, with uniform distribution of the main metal elements and their growth following a gas-liquid-solid growth mechanism. More importantly, the preparation method proposed in this invention can obtain high-entropy carbide nanowires with different metal ratios by changing the high-entropy ceramic precursor source. The technical solution proposed in this invention has the advantages of simple operation, controllable composition, low preparation temperature, short reaction time, low equipment requirements, and environmental friendliness. It is suitable for large-scale industrial production and has broad application prospects.

[0042] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0043] The following examples use instruments and equipment conventional in the art. Experimental methods in the following examples, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer. All raw materials used in the following examples are conventional commercially available products with specifications conventional in the art. In this specification and the following examples, unless otherwise specified, "%" refers to weight percentage, "parts" refers to parts by weight, and "ratio" refers to weight proportion.

[0044] Example 1

[0045] A method for preparing a flexible carbon cloth / high-entropy carbide ceramic nanowire composite material includes the following steps:

[0046] S1: 5g of a high-entropy precursor containing Ti, Nb, Zr, Mo, and Ta elements in a molar ratio of 0.2:0.2:0.2:0.2:0.2 was dispersed in xylene along with 1.5g of NaF, 1.5g of Ni(NO3)2·6H2O, and 2g of Fe(NO3)3·9H2O. The mixture was stirred for 0.5h to obtain a mixed solution.

[0047] S2: Place cotton cloth (4×4cm)2 The cotton cloth was washed with deionized water, anhydrous ethanol, and acetone respectively, and then dried in an oven at 70°C for 10 hours. The cotton cloth was then soaked in the mixed solution described in step S1 for 10 minutes, removed, and dried in an oven at 70°C for 10 hours.

[0048] S3: Place the cotton cloth obtained in step S2 above the alumina crucible, and cover the cotton cloth with another alumina crucible. Place the alumina crucible in the temperature zone of the atmosphere sintering furnace, evacuate, and control the vacuum degree of the atmosphere sintering furnace to 0.1 Pa; then introduce argon gas into the atmosphere sintering furnace at a flow rate of 10 mL / min; then heat the atmosphere sintering furnace to 1100℃ at a heating rate of 10℃ / min, and hold at this temperature for 1 hour. After that, stop heating and cool the furnace to room temperature. The cotton cloth is carbonized into flexible carbon cloth at high temperature, thus obtaining a flexible carbon cloth / high-entropy carbide ceramic nanowire composite material. The high-entropy ceramic nanowire is (Mo 0.2 Zr 0.2 Ta 0.2 Nb 0.2 Ti 0.2 C.

[0049] Example 2

[0050] A method for preparing a flexible carbon cloth / high-entropy carbide ceramic nanowire composite material includes the following steps:

[0051] S1: 2.2g of a high-entropy precursor containing Nb, Zr, Hf, and Ta in a molar ratio of 0.25:0.25:0.25:0.25 was dispersed in xylene along with 0.3g of NaF, 0.3g of Ni(NO3)2·6H2O, and 0.5g of Fe(NO3)3·9H2O. The mixture was stirred for 1 hour to obtain a mixed solution.

[0052] S2: Place cotton cloth (4×4cm) 2 The cotton cloth was washed with deionized water, anhydrous ethanol, and acetone respectively, and then dried in an oven at 70°C for 10 hours. The cotton cloth was then soaked in the mixed solution described in step S1 for 10 minutes, removed, and dried in an oven at 70°C for 10 hours.

[0053] S3: Place the cotton cloth obtained in step S2 above the alumina crucible, and cover the cotton cloth with another alumina crucible. Place the alumina crucible in the temperature zone of the atmosphere sintering furnace, evacuate, and control the vacuum degree of the atmosphere sintering furnace to 0.4 Pa; then introduce argon gas into the atmosphere sintering furnace at a flow rate of 200 mL / min; then heat the atmosphere sintering furnace to 1200℃ at a heating rate of 15℃ / min, and hold at this temperature for 2 hours. After that, stop heating and cool the furnace to room temperature. The cotton cloth is carbonized into flexible carbon cloth at high temperature, thus obtaining a flexible carbon cloth / high-entropy carbide ceramic nanowire composite material. The high-entropy ceramic nanowire is (Hf 0.25Zr 0.25 Ta 0.25 Nb 0.25 C.

[0054] Example 3

[0055] A method for preparing a flexible carbon cloth / high-entropy carbide ceramic nanowire composite material includes the following steps:

[0056] S1: 10g of a high-entropy precursor containing Ti, Nb, Zr, Hf, and V in a molar ratio of 0.2:0.2:0.2:0.2:0.2 was dispersed in xylene along with 0.3g NaF, 0.3g Ni(NO3)2·6H2O, and 0.7g Fe(NO3)3·9H2O. The mixture was stirred for 2 hours to obtain a mixed solution.

[0057] S2: Place cotton cloth (4×4cm) 2 The cotton cloth was washed with deionized water, anhydrous ethanol, and acetone respectively, and dried in an oven at 60°C for 10 hours. The cotton cloth was then soaked in the mixed solution described in step S1 for 30 minutes, removed, and dried in an oven at 70°C for 10 hours.

[0058] S3: Place the cotton cloth obtained in step S2 above the alumina crucible, and cover the cotton cloth with another alumina crucible. Place the alumina crucible in the temperature zone of the atmosphere sintering furnace, evacuate, and control the vacuum degree of the atmosphere sintering furnace to 0.2 Pa; then introduce argon gas into the atmosphere sintering furnace at a flow rate of 50 mL / min; then heat the atmosphere sintering furnace to 1150℃ at a heating rate of 20℃ / min, and hold at this temperature for 5 hours. After that, stop heating and cool the furnace to room temperature. The cotton cloth is carbonized into flexible carbon cloth at high temperature, thus obtaining a flexible carbon cloth / high-entropy carbide ceramic nanowire composite material. The high-entropy ceramic nanowire is (Hf 0.2 Zr 0.2 V 0.2 Nb 0.2 Ti 0.2 C.

[0059] Example 4

[0060] S1: 5g of a high-entropy precursor containing Ti, Nb, Zr, Hf, and V in a molar ratio of 0.2:0.2:0.2:0.2:0.2 was dispersed in xylene along with 0.5g of NaF, 0.5g of Ni(NO3)2·6H2O, and 1g of Fe(NO3)3·9H2O. The mixture was stirred for 0.5h to obtain a mixed solution.

[0061] S2: Place cotton cloth (4×4cm) 2The cotton cloth was washed with deionized water, anhydrous ethanol, and acetone respectively, and dried in an oven at 70°C for 24 hours. The cotton cloth was then soaked in the mixed solution described in step S1 for 5 minutes, removed, and dried in an oven at 70°C for 10 hours.

[0062] S3: Place the cotton cloth obtained in step S2 above the alumina crucible, and cover the cotton cloth with another alumina crucible. Place the alumina crucible in the temperature zone of the atmosphere sintering furnace, evacuate, and control the vacuum degree of the atmosphere sintering furnace to 0.1 Pa; then introduce argon gas into the atmosphere sintering furnace at a flow rate of 10 mL / min; then heat the atmosphere sintering furnace to 1200℃ at a heating rate of 7℃ / min, and hold at this temperature for 10 h, then stop heating and cool with the furnace to room temperature. The cotton cloth is carbonized into flexible carbon cloth at high temperature, thus obtaining a flexible carbon cloth / high-entropy carbide ceramic nanowire composite material. The high-entropy ceramic nanowire is (Hf 0.2 Zr 0.2 Ta 0.2 V 0.2 Ti 0.2 C.

[0063] Example 5

[0064] S1: 5g of a high-entropy precursor containing Ti, Nb, Zr, Mo, and Ta elements in a molar ratio of 0.2:0.2:0.2:0.2:0.2 was dispersed in xylene along with 0.5g of NaF, 0.5g of Ni(NO3)2·6H2O, and 1g of Fe(NO3)3·9H2O. The mixture was stirred for 0.5h to obtain a mixed solution.

[0065] S2: Place cotton cloth (4×4cm) 2 The cotton cloth was washed with deionized water, anhydrous ethanol, and acetone respectively, and dried in an oven at 100°C for 8 hours. The cotton cloth was then soaked in the mixed solution described in step S1 for 20 minutes, removed, and dried in an oven at 70°C for 10 hours.

[0066] S3: Place the cotton cloth obtained in step S2 above the alumina crucible, and cover the cotton cloth with another alumina crucible. Place the alumina crucible in the temperature zone of the atmosphere sintering furnace, evacuate, and control the vacuum degree of the atmosphere sintering furnace to 0.1 Pa; then introduce argon gas into the atmosphere sintering furnace at a flow rate of 10 mL / min; then heat the atmosphere sintering furnace to 1200℃ at a heating rate of 10℃ / min, and hold at this temperature for 4 hours. After that, stop heating and cool the furnace to room temperature. The cotton cloth is carbonized into flexible carbon cloth at high temperature, thus obtaining a flexible carbon cloth / high-entropy carbide ceramic nanowire composite material. The high-entropy ceramic nanowire is (Hf 0.2 Zr 0.2 Ta 0.2 Mo 0.2 Ti 0.2 C.

[0067] Figure 2 For folded surface growth, there is (Hf) 0.2 Zr 0.2 Ta 0.2 Mo 0.2 Ti 0.2 Digital photograph of flexible carbon cloth from high-entropy ceramic nanowires, demonstrating the excellent flexibility of the prepared material.

[0068] Figure 3 The (Hf) prepared for this invention 0.2 Zr 0.2 Ta 0.2 Nb 0.2 Ti 0.2 The XRD pattern of C nanowires shows that (Hf) 0.2 Zr 0.2 Ta 0.2 Nb 0.2 Ti 0.2 The (111), (200), (220), (311), (222), and (400) diffraction peaks of C indicate that (Hf) 0.2 Zr 0.2 Ta 0.2 Nb 0.2 Ti 0.2 The successful synthesis of C.

[0069] Figure 4 The (Hf) prepared for this invention 0.2 Zr 0.2 Ta 0.2 Nb 0.2 Ti 0.2 SEM images of carbon nanowires on a flexible carbon cloth substrate. As shown in the figures, a large number of nanowires are distributed on the surface of the carbon cloth fibers, with a diameter of approximately 100 nm and a length ranging from 2 to 8 μm. Furthermore, [the image shows]... Figure 3 Particles were observed at the bottom of the nanowires. This is consistent with (Hf) 0.2 Zr 0.2 Ta 0.2 Nb 0.2 Ti 0.2 The growth mechanism of carbon nanowires is closely related to this. The cotton cloth adsorbs sufficient precursor solution and metal catalyst, providing nucleation sites and reaction raw materials for nanowire growth at high temperature; in addition, the carbon-containing small molecules released by the carbonization of the cotton cloth itself can serve as carbon sources for nanowire growth. The further acquisition of metal and carbon sources by the nanowires leads to changes in diameter and length.

[0070] Figure 5 The (Hf) prepared for this invention 0.2 Zr 0.2 Ta0.2 Nb 0.2 Ti 0.2 HAADF images and corresponding surface scan spectroscopy of C nanowires. From Figure 5 It can be seen that Hf 、 Zr 、 Ta 、 Nb 、 The five elements Ti are uniformly distributed in the nanowire portion; the spherical catalyst at the nanowire tip is mainly composed of Fe and Ni, indicating that the growth of this high-entropy nanowire is driven by a gas-liquid-solid growth mechanism. Furthermore, the use of a binary catalyst effectively reduces (Hf... 0.2 Zr 0.2 Ta 0.2 Nb 0.2 Ti 0.2 The preparation temperature of C nanowires is relatively low. Therefore, the technical solution provided by this invention is not only simple but also reduces the preparation temperature, thereby lowering the preparation cost to a certain extent.

[0071] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

[0072] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A method for preparing a flexible carbon cloth / high-entropy carbide ceramic nanowire composite material, characterized in that, Includes the following steps: S1: Disperse the high-entropy ceramic precursor with NaF, Ni(NO3)2·6H2O and Fe(NO3)3·9H2O in xylene and stir to obtain a mixed solution; S2: After impregnating and drying the cotton cloth in the mixed solution, it is then subjected to vacuum calcination under an inert atmosphere to obtain the flexible carbon cloth / high entropy carbide ceramic nanowire composite material. The high-entropy ceramic precursor is an organic precursor composed of at least four metallic elements selected from Ti, Nb, Zr, Hf, Ta, Mo, and V. In step S2, during the vacuum calcination process, the vacuum degree is 0.1~0.4Pa, the argon flow rate is 10~200 mL / min, the calcination temperature is 1000~1200℃, and the calcination time is 1~10h; during the calcination process, the heating rate is 5~20℃ / min.

2. The method for preparing a flexible carbon cloth / high-entropy carbide ceramic nanowire composite material according to claim 1, characterized in that, The mass ratio of the high-entropy ceramic precursor to NaF, Ni(NO3)2·6H2O and Fe(NO3)3·9H2O is (0.5~1.5):(0.05~0.15):(0.05~0.15):(0.1~0.3).

3. The method for preparing a flexible carbon cloth / high-entropy carbide ceramic nanowire composite material according to claim 1, characterized in that, In step S1, the stirring time is 0.5~2h.

4. The method for preparing a flexible carbon cloth / high-entropy carbide ceramic nanowire composite material according to claim 1, characterized in that, In step S2, before placing the cotton fabric in the mixed solution, the cotton fabric is pretreated. The pretreatment includes washing the cotton fabric sequentially with deionized water, anhydrous ethanol, and acetone, and then drying it in an oven.

5. The method for preparing a flexible carbon cloth / high-entropy carbide ceramic nanowire composite material according to claim 4, characterized in that, After pretreatment, the drying temperature is 60~100℃ and the drying time is 8~24h.

6. The method for preparing a flexible carbon cloth / high-entropy carbide ceramic nanowire composite material according to claim 1, characterized in that, In step S2, the cotton is immersed in the mixed solution for 5-30 minutes, and then dried at a temperature of 60-100°C for 5-24 hours.

7. A flexible carbon cloth / high-entropy carbide ceramic nanowire composite material, characterized in that, It is prepared by the method described in any one of claims 1 to 6.

8. The application of the flexible carbon cloth / high-entropy carbide ceramic nanowire composite material as described in claim 7 in the fields of energy storage and conversion, catalysis, electromagnetic shielding and wave absorption.

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