A high-entropy dual-phase sulfide and a preparation method and application thereof

Abstract

The application discloses a kind of high-entropy dual-phase sulfide and its preparation method and application, belong to electromagnetic wave absorbing material field.The application wants to solve how to enhance the weak interface polarization effect of high-entropy sulfide in electromagnetic attenuation problem.The application introduces Cu and Al metal elements into multi-metal sulfide by solvothermal and annealing method, and synthesizes a kind of six-component high-entropy sulfide wave-absorbing material (6-HES) with dual-phase structure, wherein all metal elements are uniformly distributed in M9S8 and MS (M represents metal element) two phases with crystal lattice defects.The high-entropy dual-phase sulfide prepared by the method has heterogeneous interface structure and rich vacancy defects, which not only can improve its conductance loss, but also can enhance defect-induced polarization and interface loss.The application taps the potential of multi-metal sulfide in the field of electromagnetic attenuation.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of electromagnetic wave absorbing materials, and particularly relates to a high-entropy double-phase sulfide as well as a preparation method and application thereof. BACKGROUND

[0002] The vigorous development of the intelligent era, especially the entry into the 5G era or the future 6G era, has significantly promoted the wide application of high-frequency intelligent electromagnetic equipment represented by gigahertz (GHz) frequency, but the problems such as information leakage and electromagnetic pollution caused thereby have become increasingly serious. Since the electronic structure, lattice defects and phase composition of multi-metal sulfides can be improved by introducing metal elements to improve the dielectric response, they have attracted widespread attention in terms of alleviating electromagnetic problems.

[0003] According to the Hume-Rothery theory, metal elements with different ionic radii and electronegativities introduced into multi-metal sulfides can create lattice defects in specific crystal phases (Small 2024, 2309773). The vacancy defects can act as defect centers to enhance defect-induced polarization loss (Nano-Micro Lett. 2025, 17, 24.). However, the improvement of dielectric loss by introducing only sulfur vacancies to enhance polarization effect is relatively single, which hinders the further development potential of multi-metal sulfides in electromagnetic attenuation. It is worth emphasizing that the high-entropy sulfides disclosed in application numbers 202311174922.X (publication (announcement) number: CN117039135A, publication (announcement) date: 20231110) and 202410638819.4 (publication (announcement) number: CN118600455A, publication (announcement) date: 20240906) exhibit characteristics of improving electrical conductivity. In addition, constructing a multi-phase structure with a hetero-interface is another effective method to improve polarization loss, specifically, opposite charges tend to accumulate at the hetero-interface, thereby generating interface polarization to attenuate electromagnetic wave energy (Adv. Funct. Mater. 2022, 2204370). However, traditional multi-metal sulfides have the problem of element separation, making it difficult to simultaneously achieve the above modulation methods to attenuate electromagnetic wave energy.

[0004] The high configurational entropy of high-entropy material with application number 202410595991.6 (publication number CN118507749A, publication date: 20240816) can make multiple metals uniformly dispersed in a specific phase, thereby avoiding the separation of multiple elements. However, high configurational entropy generally promotes the formation of single-phase structure rather than multi-phase structure, which directly weakens or even eliminates the promoting effect of interface polarization in the electromagnetic wave energy attenuation process in high-entropy sulfides. In addition, the strong reactivity makes certain metal atoms have a priority in chemical reaction, thereby preferentially forming certain crystal phases during synthesis (Adv. Sci. 2023, 2307649). Therefore, on the basis of improving the electrical conduction loss and defect-induced polarization loss, how to enhance the weak interface polarization effect of high-entropy sulfides in electromagnetic attenuation is of great significance. SUMMARY

[0005] In order to make up for the shortcomings of the existing preparation technology, the application provides a high-entropy dual-phase sulfide wave-absorbing material and a preparation method thereof. By means of the high-entropy strategy, the application introduces Cu and Al metal elements into the multi-metal sulfide by using the solvothermal and annealing methods, and synthesizes a six-component high-entropy sulfide wave-absorbing material (6-HES) with a dual-phase structure, in which all metal elements are uniformly distributed in two phases of M9S8 and MS (M represents a metal element) with lattice defects. The high-entropy dual-phase sulfide prepared by the method has a heterogeneous interface structure and rich vacancy defects, which not only can improve the electrical conduction loss, but also can enhance the defect-induced polarization and interface loss. By simultaneously exerting the effects of the three loss mechanisms, the 6-HES obtains optimized impedance matching and attenuation coefficient, thereby obtaining excellent electromagnetic wave absorption performance.

[0006] In order to achieve the above technical problems, the application adopts the following technical solutions:

[0007] The application aims to provide a high-entropy dual-phase sulfide, which includes six metal elements of iron, cobalt, nickel, chromium, copper and aluminum, and the atomic composition of each metal element accounts for 10%-30%, and the high-entropy dual-phase sulfide has M9S8 cubic structure and MS hexagonal structure.

[0008] Further limitation, the high-entropy dual-phase sulfide is a particle with a particle size mainly concentrated in 1-5 microns, and a yolk shell structure.

[0009] Further limitation, the mixing entropy of the high-entropy dual-phase sulfide is greater than or equal to 17.625 J / Mol / K.

[0010] The application further provides a preparation method of the high-entropy dual-phase sulfide, which uses Fe(NO3)3·9H2O (mass purity 99%), Co(NO3)2·6H2O (mass purity 99%), Ni(NO3)3·6H2O (mass purity 98%), Cr(NO3)2·9H2O (mass purity 98.5%), Cu(NO3)2·3H2O (mass purity 98.5%) and Al(NO3)3·9H2O (mass purity 99%) metal nitrate as raw materials, and comprises the following steps:

[0011] Step one: glycerol is introduced into isopropyl alcohol, and metal element nitrate is added and stirred until uniform to obtain a uniformly mixed suspension, the obtained suspension is subjected to a solvothermal reaction, and is left to cool, centrifugal washing is performed with anhydrous ethanol until the supernatant is clear, vacuum drying is performed, and a precursor is obtained;

[0012] Step two: the precursor is dissolved in anhydrous ethanol, thioacetamide is added and stirred until uniform to obtain a uniformly mixed suspension, the obtained suspension is subjected to a solvothermal reaction, and is left to cool, centrifugal washing is performed on the precipitate with anhydrous ethanol until the supernatant is clear, vacuum drying is performed, annealing is performed under inert gas protection, the furnace is cooled to room temperature, and a high-entropy dual-phase sulfide is obtained.

[0013] Further limitation, in step one, 1mL-10mL of glycerol is introduced into 20mL-80mL of isopropyl alcohol, and the amount of substance of each metal nitrate is 1mmol-5mmol.

[0014] Further limitation, in step one, the stirring rate is 500r / min-1000r / min; and the stirring time is generally controlled to be 30min-60min.

[0015] Further limitation, in step one, the solvothermal reaction is performed at 120℃-180℃ for 6h-12h; and the solvothermal reaction can be performed in a stainless steel autoclave lined with Teflon.

[0016] Further limitation, in step one, the centrifuge speed is controlled to be 8000r / min-12000r / min.

[0017] Further limitation, in step one, the vacuum drying in step one is performed in a vacuum oven at 60℃-80℃ for 8h-16h.

[0018] Further limitation, in step two, 50mg-100mg of the precursor is dissolved in 30mL-60mL of anhydrous ethanol, and the amount of thioacetamide is 160mg-190mg.

[0019] Further limited, the stirring rate in step two is 500r / min-1000r / min; the stirring time is generally controlled in 30min-60min.

[0020] Further limited, in step two, the solvothermal reaction is carried out at 150℃-180℃ for 6h-12h; the solvothermal reaction can be carried out in a Teflon-lined stainless steel autoclave.

[0021] Further limited, in step two, the annealing process is: heating at a rate of 2℃ / min-7℃ / min to 400℃-500℃, annealing for 1h-3h, the inert gas is argon, and the annealing is carried out in a tube furnace by placing the dried precipitate in an alumina corundum crucible and placing it in the tube furnace, then the gas in the tube furnace is extracted and filled with argon, and then heated.

[0022] Further limited, in step two, the centrifuge speed is controlled in 8000r / min-12000r / min.

[0023] Further limited, in step one, the vacuum drying in step two is carried out in a vacuum oven at 60℃-80℃ for 8h-16h.

[0024] The high-entropy double-phase sulfide or the high-entropy double-phase sulfide prepared by the method is used as an electromagnetic wave absorbing material.

[0025] Compared with the prior art, the present application has the following beneficial effects:

[0026] The present application synthesizes a high-entropy double-phase sulfide absorbing material with crystal defects, wherein the high-entropy effect adjusts the electronic structure, resulting in the improvement of electrical conductivity and electrical conductivity loss, the increase of crystal defect density resulting in the enhancement of defect-induced polarization loss, plus the interface polarization excited by the double-phase interface, which together improve the electromagnetic wave absorption performance.

[0027] The present application synthesizes a high-entropy sulfide with a double-phase structure by selecting metal elements Cu and Al, eliminates the weak interface polarization effect of high-entropy sulfide, and fully explores the potential of multi-metal sulfide in the field of electromagnetic attenuation.

[0028] The preparation process of the present application is simple in operation, low in equipment requirement and low in cost.

[0029] In order to further understand the features and technical contents of the present application, please refer to the following detailed description of the present application and the accompanying drawings, however, the accompanying drawings are provided for reference and illustration only, and are not used to limit the present application. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1X-ray diffraction (XRD) pattern of the five-element high-entropy dual-phase sulfide in the comparative example of the present application;

[0031] Figure 2 Scanning electron microscope image (SEM) and element distribution map (EDS) of the five-element high-entropy dual-phase sulfide in the comparative example of the present application;

[0032] Figure 3 Electromagnetic wave absorption performance graph of the five-element high-entropy dual-phase sulfide in the comparative example of the present application;

[0033] Figure 4 X-ray diffraction (XRD) pattern of the six-element high-entropy dual-phase sulfide in Example 1 of the present application;

[0034] Figure 5 Scanning electron microscope image (SEM) and element distribution map (EDS) of the six-element high-entropy dual-phase sulfide in Example 1 of the present application;

[0035] Figure 6 Electromagnetic wave absorption performance graph of the six-element high-entropy dual-phase sulfide in Example 1 of the present application. DETAILED DESCRIPTION

[0036] The present application will be described in detail below with reference to specific embodiments. The following examples will help those skilled in the art to further understand the present application, and do not limit the present application in any form. It should be noted that, for those skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made. These all belong to the protection scope of the present application.

[0037] Example 1: The preparation method of the six-element high-entropy dual-phase sulfide in this embodiment is realized by the following steps:

[0038] I. Take 34 mL of isopropyl alcohol into a beaker, and introduce 6 mL of glycerol into the isopropyl alcohol.

[0039] II. Take 0.5 mmol of Fe(NO3)3·9H2O (mass purity 99%), Co(NO3)2·6H2O (mass purity 99%), Ni(NO3)3·6H2O (mass purity 98%), Cr(NO3)2·9H2O (mass purity 98.5%), Cu(NO3)2·3H2O (mass purity 98.5%), and Al(NO3)3·9H2O (mass purity 99%) metal nitrate as raw materials, respectively, and dissolve them in the mixed solution obtained in step I. Then, the solution is stirred at a speed of 800 r / min for 30 min to obtain a uniformly mixed suspension.

[0040] III. The obtained suspension was transferred into a 100 ml Teflon-lined stainless steel autoclave and subjected to solvothermal reaction at 150 °C for 10 h. The reaction product was obtained after cooling and standing.

[0041] IV. The reaction product was centrifuged several times with anhydrous ethanol until the supernatant was clear, and the centrifuge speed was 8000 r / min. Then, the product was dried in a vacuum oven at 60 °C for 8 h, and the obtained powder was collected to obtain the precursor of the synthesized high-entropy double-phase sulfide.

[0042] V. 100 mg of the prepared metal precursor was dissolved in 50 mL of anhydrous ethanol, and then 167 mg of thioacetamide was added to the mixed solution and stirred for 30 min to obtain a uniform suspension.

[0043] VI. The above-mentioned liquid was transferred into a 100 mL Teflon-lined stainless steel autoclave for solvothermal reaction, and the reaction temperature was 160 °C and the reaction time was 8 h.

[0044] VII. The heated liquid was cooled and poured into a centrifuge tube, and the precipitate was washed with anhydrous ethanol and subjected to solid-liquid separation by a centrifuge (8000 r / min). The washing was repeated three times until the supernatant was clear. The centrifuged product was placed in a vacuum drying oven at 60 °C for 8 h, and then the obtained powder was collected.

[0045] VIII. The dried precipitate was placed in an alumina corundum crucible and placed in a tube furnace. After the gas in the tube furnace was exhausted, argon was filled, and the sample was annealed in the tube furnace at 500 °C for 2 h, with a heating rate of 5 °C / min. The furnace was cooled to room temperature, and the final sample was obtained.

[0046] Comparative Example: The preparation method of the five-element high-entropy double-phase sulfide was carried out according to the following steps: I. 50 mL of isopropanol was weighed into a beaker, and 10 mL of glycerol was introduced into the isopropanol.

[0047] II. 2 mmol of Fe(NO3)3·9H2O (mass purity 99%), Co(NO3)2·6H2O (mass purity 99%), Ni(NO3)3·6H2O (mass purity 98%), Cr(NO3)2·9H2O (mass purity 98.5%), and Cu(NO3)2·3H2O (mass purity 98.5%) metal nitrate salts were respectively taken as raw materials and dissolved in the above-mentioned mixed solution. Then, the solution was stirred for 30 min to obtain a uniform suspension.

[0048] III. The obtained suspension was transferred into a 100 ml Teflon-lined stainless steel autoclave and subjected to solvothermal reaction at 150 °C for 10 h. The reaction product was obtained after cooling and standing.

[0049] IV. The reaction product was centrifuged several times with anhydrous ethanol until the supernatant was clear, with the centrifuge speed ranging from 10,000 r / min. It was then dried in a vacuum oven at 60°C for 8 hours, and the resulting powder was collected to obtain the precursor for the synthesis of high-entropy biphase sulfides.

[0050] 5. Dissolve 100 mg of the prepared metal precursor in 50 mL of anhydrous ethanol, then add 188 mg of thioacetamide to the mixture and stir for 30 min to obtain a uniform suspension.

[0051] 6. Transfer the above liquid to a 100mL stainless steel autoclave lined with polytetrafluoroethylene for a solvothermal reaction at a temperature of 160℃ for 8 hours.

[0052] 7. After cooling, the heated liquid is poured into centrifuge tubes, and the precipitate is washed with anhydrous ethanol. Solid-liquid separation is then performed using a centrifuge (10,000 r / min), and the mixture is washed three times until a clear supernatant is obtained. The centrifuged product is then placed in a vacuum drying oven at 60°C and dried for 12 hours, after which the resulting powder is collected.

[0053] 8. Place the dried precipitate in an alumina corundum crucible and place it inside a tube furnace. After evacuating the gas from the tube furnace, fill it with argon and anneal it in the tube furnace at 500℃ for 2 hours, with a heating rate of 5℃ / min. Cool the furnace to room temperature and finally remove the sample to obtain a high-entropy biphase sulfide.

[0054] The XRD pattern of a pentagonal high-entropy biphase sulfide prepared from five metals and sulfur is shown in the figure. Figure 1 As shown, by Figure 1 It can be seen that the two phases of the high-entropy biphase sulfide are M9S8 and MS, where M represents a metal element.

[0055] SEM images of pentagonal high-entropy biphase sulfides prepared from five metals and sulfur are shown below. Figure 2 As shown, by Figure 2 It can be seen that all the metal elements are uniformly distributed in the two phases, and no element separation phenomenon occurs. Combined with the XRD results, the method successfully synthesizes high-entropy sulfides with two phases, M9S8 and MS.

[0056] Figure 3 The diagram shows the reflection loss characteristics of a pentagonal high-entropy two-phase sulfide prepared from five metals and sulfur. Figure 3 As shown, by Figure 3 It can be seen that the reflection loss value of the five-component high-entropy biphase sulfide is -26.7dB and the effective absorption bandwidth is 4.08GHz, indicating that the high-entropy sulfide with M9S8 and MS phases exhibits excellent electromagnetic wave absorption performance.

[0057] The XRD pattern of a hexa-component high-entropy biphase sulfide prepared from six metals and sulfur is shown in the figure. Figure 4 As shown, by Figure 4 It can be seen that the two phases of the high-entropy biphase sulfide are M9S8 and MS, where M represents a metal element.

[0058] SEM images of hexa-component high-entropy biphase sulfides prepared from six metals and sulfur are shown below. Figure 5 As shown, by Figure 5 It can be seen that all the metal elements are uniformly distributed in the two phases, and no element separation phenomenon occurs. Combined with the XRD results, the method successfully synthesizes high-entropy sulfides with two phases, M9S8 and MS.

[0059] The reflection loss characteristics of a hexa-component high-entropy biphase sulfide prepared from six metals and sulfur are shown in the figure below. Figure 6 As shown, by Figure 6 It can be seen that the reflection loss value of the six-component high-entropy biphase sulfide is -43.05dB and the effective absorption bandwidth is 4.96GHz, indicating that the high-entropy sulfide with M9S8 and MS phases exhibits excellent electromagnetic wave absorption performance.

[0060] The specific embodiments of the present invention have been described above. It should be noted that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various modifications or variations within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. A high-entropy dual-phase sulfide, characterized in that, The six metal elements include iron, cobalt, nickel, chromium, copper and aluminum, and the atomic composition of each metal element accounts for 10-30%, has M9S8 cubic structure and MS hexagonal structure, is in granular form, the particle size is concentrated in 1-5 μm, and has an egg yolk shell structure.

2. The high-entropy dual-phase sulfide of claim 1, wherein, The mixing entropy is greater than or equal to 17.625 J / Mol / K.

3. A method of producing the high-entropy dual-phase sulfide according to claim 1 or 2, characterized by, The method comprises the following steps: Step one, glycerol is introduced into isopropyl alcohol, nitrate of metal element is added, stirring is performed until uniform, solvothermal reaction is performed at 120-180 DEG C, standing and cooling are performed, centrifugal washing is performed with anhydrous ethanol until the supernatant is clear, vacuum drying is performed, and a precursor is obtained; Step two, the precursor is dissolved in anhydrous ethanol, thioacetamide is added, stirring is performed until uniform, solvothermal reaction is performed at 150-180 DEG C, centrifugal washing is performed with anhydrous ethanol after cooling, the precipitate is washed until the supernatant is clear, vacuum drying is performed, annealing is performed under inert gas protection, furnace cooling is performed to room temperature, and a high-entropy dual-phase sulfide is obtained.

4. The method of claim 3, wherein, In step one, 1-10 mL of glycerol is introduced into 20-80 mL of isopropyl alcohol, and the amount of substance of each metal nitrate is 1-5 mmol.

5. The method of claim 3, wherein, In step one, the solvothermal reaction is performed for 6-12 h.

6. The method of claim 3, wherein, In step two, 50-100 mg of the precursor is dissolved in 30-60 mL of anhydrous ethanol, and the amount of thioacetamide is 160-190 mg.

7. The method of claim 3, wherein In step two, the solvothermal reaction is performed for 6-12 h.

8. The method of claim 3, wherein, In step two, the annealing process is as follows: heating is performed at a rate of 2-7 DEG C / min to 400-500 DEG C, and annealing is performed for 1-3 h, and the inert gas is argon.

9. The high-entropy dual-phase sulfide of any one of claims 1-2 or the high-entropy dual-phase sulfide prepared by the method of any one of claims 3-8 is used as an electromagnetic wave absorbing material.

Images