Preparation method of titanium dioxide and high-entropy alloy composite material for ion battery

Abstract

The invention discloses a preparation method of a titanium dioxide and high-entropy alloy composite material for an ion battery, and belongs to the technical field of preparation of battery materials and nano composite materials. The method comprises the following steps: uniformly mixing titanium dioxide nanoparticles and a high-entropy alloy precursor; in an inert atmosphere, placing the composite precursor and metal sodium in a sealed environment together, heating to a preset temperature, carrying out a reduction reaction, and carrying out heat preservation at the temperature for a period of time; and removing residual metal sodium from the obtained product in an inert atmosphere, and cleaning and drying the final product. The composite materials with different chemical components can be prepared by controlling the types and contents of metal elements in the high-entropy alloy precursor. In the prepared composite material, the high-entropy alloy nanoparticles are uniformly loaded on the surfaces of the anatase-phase titanium dioxide nanoparticles, so that the conductivity and the ion diffusion rate of the material are effectively improved, and the composite material shows excellent electrochemical performance when being applied to negative electrodes of lithium-ion and sodium-ion batteries.

Description

Technical Field

[0001] This invention belongs to the field of battery materials and nanocomposite material preparation technology, specifically relating to a method for preparing titanium dioxide and high-entropy alloy composite materials (i.e., titanium dioxide / high-entropy alloy) for ion batteries. Background Technology

[0002] Titanium dioxide (TiO2) is abundant, inexpensive, structurally stable, and has a safe sodium intercalation potential (approximately 0.8 V vs. Na / Na). + With its advantages such as low intrinsic electronic conductivity and small volume change during cycling, sodium-ion battery anode material is considered a promising material for applications. However, its low intrinsic electronic conductivity and ion diffusion coefficient result in poor rate performance and unsatisfactory reversible specific capacity, which severely restricts its practical application.

[0003] To overcome the aforementioned drawbacks, existing technologies typically employ carbon coating, doping, and nanostructuring to improve the electrochemical properties of titanium dioxide. However, carbon coating may induce a crystal transformation in titanium dioxide during high-temperature processing (e.g., from the highly electrochemically active anatase phase to the less sodium-storing rutile phase), and simple carbon composites offer limited improvement in ion diffusion capabilities. While doping can improve conductivity to some extent, the effect is often insufficient and may introduce impurity phases. With the advancement of materials science, high-entropy alloys, as a novel multifunctional material, offer new possibilities for solving these problems.

[0004] High-entropy alloys are a novel type of material composed of five or more main metallic elements in equiatomic or near-equiatomic ratios. Their unique "high-entropy effect" endows them with excellent mechanical properties, corrosion resistance, and thermal stability. In recent years, the application of high-entropy alloys in energy fields such as electrocatalysis and lithium / sodium-ion batteries has begun to attract attention. Combining them with titanium dioxide is expected to synergistically leverage the excellent conductivity of high-entropy alloys and the structural stability of titanium dioxide, thereby significantly improving the overall performance of the material by constructing a highly efficient electron conduction network. However, achieving efficient composite composition still faces challenges. Traditional composite strategies (such as mechanical mixing and wet impregnation) often struggle to achieve uniform and stable interfacial bonding at the nanoscale and are frequently constrained by high-temperature processing, leading to active phase aggregation, crystal transformation, or interfacial failure.

[0005] Molten sodium reduction, as an effective low-temperature reduction technique, exhibits unique advantages in the preparation of elemental metal nanoparticles. On one hand, molten sodium can simultaneously reduce multiple metal precursors, making the direct synthesis of high-entropy alloys possible. On the other hand, the low-temperature reaction environment is beneficial for maintaining the structural stability of titanium dioxide and avoiding crystal transformations caused by high temperatures. This theoretically gives it the potential to construct nanostructured titanium dioxide / high-entropy alloy composites. However, existing patents and research mostly focus on using this method to prepare single metal nanoparticles or binary alloys, and its application in directly constructing nanocomposite structures of titanium dioxide and complex multi-component high-entropy alloys has not yet been observed. Achieving uniform and stable nanoscale composites of titanium dioxide and high-entropy alloys, and fully utilizing their synergistic effects, remains an unsolved technical challenge in this field. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a method for preparing titanium dioxide and high-entropy alloy composite materials for lithium-ion batteries. Based on molten sodium reduction, this method, through raw material design and process control, aims to solve the problems of poor conductivity, slow ion diffusion kinetics, and insufficient structural stability of existing titanium dioxide anode materials. The prepared material exhibits both high conductivity and high structural stability, demonstrating excellent anode performance for lithium and sodium-ion batteries.

[0007] The specific technical solution adopted in this invention is as follows: In a first aspect, the present invention provides a method for preparing a titanium dioxide and high-entropy alloy composite material for ion batteries, as detailed below: S1: Titanium dioxide nanoparticles and high-entropy alloy precursors are uniformly mixed by ball milling to obtain a uniform composite precursor. S2: Under an inert atmosphere, the composite precursor and metallic sodium are placed together in a sealed environment, heated to a preset temperature for a reduction reaction, and kept at this temperature for a period of time. S3: Under an inert atmosphere, the product obtained in S2 is cleaned of residual metallic sodium, and the final product is washed and dried to obtain a titanium dioxide and high-entropy alloy composite material for ion batteries.

[0008] Preferably, the titanium dioxide nanoparticles have a size of 5-100 nm and a crystal form of anatase.

[0009] Preferably, the high-entropy alloy contains at least five metallic elements, including iron, manganese, cobalt, bismuth, tin, titanium, vanadium, chromium, nickel, copper, zirconium, niobium, and molybdenum; the high-entropy alloy precursor is an oxide or chloride of the corresponding metallic element.

[0010] Preferably, the ball milling process is controlled at 200-300 rpm, the ball-to-material ratio is (10-15):1, and the ball milling time is 3-4 hours.

[0011] Preferably, the molar ratio of each metal element in the titanium dioxide nanoparticles and the high-entropy alloy precursor is consistent, ranging from (20~1):1.

[0012] Preferably, the mass ratio of the metallic sodium to the composite precursor is (1~5):1.

[0013] Preferably, in the reduction reaction, the preset temperature is 200~400 ℃ and the holding time is 0.5~1 hour.

[0014] Preferably, the residual metallic sodium is removed by anhydrous ethanol.

[0015] Preferably, the washing and drying of the final product is carried out in an air atmosphere.

[0016] In a second aspect, the present invention provides a titanium dioxide and high-entropy alloy composite material for ion batteries obtained by the preparation method described in any one of the first aspects.

[0017] Thirdly, the present invention provides an application of titanium dioxide and high-entropy alloy composite materials for ion batteries as described in the second aspect in the anode material of ion batteries.

[0018] Compared with the prior art, the present invention has the following advantages: 1) Significant synergistic effect: This invention introduces a high-entropy alloy into the titanium dioxide matrix. The high-entropy alloy, as a highly efficient electronic conductor network, significantly improves the overall electronic conductivity of the composite material. The heterojunction interface formed between the high-entropy alloy and titanium dioxide promotes ion adsorption and transport. Furthermore, the active metal component in the high-entropy alloy itself possesses a high theoretical specific capacity, providing additional capacity contribution to the composite material. The synergistic effect of these two factors jointly enhances the rate performance and specific capacity of the material.

[0019] 2) Structural stability: The high-entropy alloy nanoparticles generated in situ by the molten sodium reduction method are firmly bonded to the titanium dioxide substrate. During the charging and discharging process, they can effectively suppress the aggregation and structural collapse of titanium dioxide particles and buffer volume changes, thereby endowing the composite material with excellent long-term cycle stability.

[0020] 3) Significant performance improvement: When the composite material of the present invention is used as the negative electrode of lithium-ion or sodium-ion batteries, its initial coulombic efficiency, reversible specific capacity, rate performance and cycle life are significantly improved compared with pure titanium dioxide. Attached Figure Description

[0021] Figure 1The image shows the XRD pattern of the nanostructured titanium dioxide and high-entropy alloy composite material prepared in Example 1.

[0022] Figure 2 The image shows a scanning electron microscope (SEM) image of the nanostructured titanium dioxide and high-entropy alloy composite material prepared in Example 1.

[0023] Figure 3 The image shows the energy spectrum of the nanostructured titanium dioxide and high-entropy alloy composite material prepared in Example 1.

[0024] Figure 4 The constant current charge-discharge curves are for the nanostructured titanium dioxide and high-entropy alloy composite material prepared in Example 1. Detailed Implementation

[0025] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below. Technical features in various embodiments of the present invention can be combined accordingly without mutual conflict.

[0026] This invention provides a method for preparing a titanium dioxide and high-entropy alloy composite material for ion batteries, the specific preparation method being as follows: 1) Raw material weighing: Weigh titanium dioxide nanoparticles and high-entropy alloy precursors according to a certain stoichiometric ratio.

[0027] In a preferred embodiment of the present invention, the titanium dioxide nanoparticles have a size of 5-100 nm and a crystal form of anatase.

[0028] In a preferred embodiment of the present invention, the high-entropy alloy comprises at least five metallic elements, including iron (Fe), manganese (Mn), cobalt (Co), bismuth (Bi), tin (Sn), titanium (Ti), vanadium (V), chromium (Cr), nickel (Ni), copper (Cu), zirconium (Zr), niobium (Nb), and molybdenum (Mo). The high-entropy alloy precursor can preferably be an oxide or chloride of the corresponding metallic element, regardless of its specific valence state.

[0029] In a preferred embodiment of the present invention, the molar ratio of each metal element in the titanium dioxide nanoparticles and the high-entropy alloy precursor is consistent, ranging from (20~1):1.

[0030] 2) Precursor mixing: The above raw materials (titanium dioxide nanoparticles and high-entropy alloy precursor) are uniformly mixed by ball milling to ensure that a uniform composite precursor is obtained.

[0031] In a preferred embodiment of the present invention, during the ball milling process, the rotation speed is controlled at 200~300 rpm, the ball-to-material ratio is (10~15):1, and the ball milling time is 3~4 hours.

[0032] 3) Reduction reaction: In a glove box filled with inert gas, the composite precursor and metallic sodium are placed together in a closed reactor, heated to a preset temperature to carry out the reduction reaction, and kept at this temperature for a period of time.

[0033] In a preferred embodiment of the present invention, the amount of sodium metal is more than 1 times the mass of the composite precursor to ensure that the high-entropy alloy precursor is completely reduced. For example, the mass ratio of sodium metal to the composite precursor can be (1~5):1.

[0034] In a preferred embodiment of the present invention, the preset temperature in the reduction reaction is 200~400 ℃, and the holding time is 0.5~1 hour.

[0035] 4) Cleaning and storage: In a glove box filled with inert gas, residual metallic sodium is removed with anhydrous ethanol. The product is then removed from the glove box, further cleaned and dried in the air to obtain a titanium dioxide and high-entropy alloy composite material for ion batteries. The obtained material can be placed in a glove box for long-term storage.

[0036] In a preferred embodiment of the present invention, drying can be carried out using a vacuum drying oven.

[0037] The present invention will be further described and illustrated below with reference to specific embodiments.

[0038] Example 1 This embodiment prepares a titanium dioxide and high-entropy alloy composite material for ion batteries. The specific preparation method is as follows: 1) Weigh 0.01 mol titanium dioxide, 0.00067 mol cobalt tetroxide (Co3O4), 0.002 mol manganese dioxide (MnO2), 0.001 mol iron oxide (Fe2O3), 0.001 mol bismuth oxide (Bi2O3) and 0.002 mol stannous oxide (SnO) as reaction raw materials, weigh grinding balls at a ball-to-material ratio of 15:1, and ball mill at 250 rpm for 3 hours to mix them evenly.

[0039] 2) Weigh 3g of metallic sodium in an argon atmosphere glove box, place it in a sealed crucible and heat it to 200°C to obtain liquid metallic sodium. Weigh 1g of the powder obtained in step 1), add it to the liquid metallic sodium and mix thoroughly. Keep it at 200°C for 0.5 hours and then let it cool naturally.

[0040] 3) Transfer the product from step 2) to a beaker inside a glove box and add sufficient anhydrous ethanol to remove residual metallic sodium.

[0041] 4) Remove the product obtained in step 3) from the glove box, then quickly wash the product by vacuum filtration with anhydrous ethanol as the medium, and then place the product in a vacuum drying oven at 60 °C to dry it thoroughly. After drying, store the product in a glove box filled with argon gas.

[0042] The sample prepared by the above process in this embodiment is a nanostructured TiO2 / CoMnFeBiSn composite material, wherein the molar ratio of titanium dioxide to each metal element in the high-entropy alloy is controlled at 5:1.

[0043] The samples prepared in this embodiment were characterized and tested, and the results are as follows: Figures 1-4 As shown. Figure 1 The XRD pattern of the sample prepared by this process shows that the sample is a two-phase composite structure composed of anatase titanium dioxide and face-centered cubic high-entropy alloy. Figure 2 This is a scanning electron microscope (SEM) image of the sample. The image shows that the material is composed of uniform nanoparticles with a particle size distribution ranging from 5 to 100 nm. The elemental distribution was also analyzed using EDS, such as... Figure 3 As shown in the energy spectrum, five metallic elements are uniformly distributed on the titanium dioxide matrix. Figure 4 This is the galvanostatic charge-discharge curve of the sample. The image shows that the charge-discharge rate is within the range of 0.01~3 V (vs. Na / Na). + Voltage range, 0.1 C (1 C = 335 mA g) -1 The sample specific capacity at the current density was 387.8 mAh g. -1 The first week's coulomb efficiency was 61.9%, demonstrating good reversible specific capacity.

[0044] Example 2 This embodiment prepares a titanium dioxide and high-entropy alloy composite material for ion batteries. The specific preparation method is as follows: 1) Weigh 0.001 mol titanium dioxide, 0.00033 mol cobalt tetroxide (Co3O4), 0.001 mol manganese dioxide (MnO2), 0.0005 mol iron oxide (Fe2O3), 0.0005 mol bismuth oxide (Bi2O3) and 0.001 mol stannous oxide (SnO) as reaction raw materials, weigh grinding balls at a ball-to-material ratio of 15:1, and ball mill at 250 rpm for 3 hours to mix them evenly.

[0045] 2) Weigh 3g of metallic sodium in an argon atmosphere glove box, place it in a sealed crucible and heat it to 200°C to obtain liquid metallic sodium. Weigh 1g of the powder obtained in step 1), add it to the liquid metallic sodium and mix thoroughly. Keep it at 200°C for 1 hour and then let it cool naturally.

[0046] 3) Transfer the product from step 2) to a beaker inside a glove box and add sufficient anhydrous ethanol to remove residual metallic sodium.

[0047] 4) Remove the product obtained in step 3) from the glove box, then quickly wash the product by vacuum filtration with anhydrous ethanol as the medium, and then place the product in a vacuum drying oven at 60 °C to dry it thoroughly. After drying, store the product in a glove box filled with argon gas.

[0048] The sample prepared by the above process in this embodiment is a nanostructured TiO2 / CoMnFeBiSn composite material, wherein the molar ratio of titanium dioxide to each metal element in the high-entropy alloy is controlled at 10:1.

[0049] Example 3 This embodiment prepares a titanium dioxide and high-entropy alloy composite material for ion batteries. The specific preparation method is as follows: 1) Weigh 0.01 mol titanium dioxide, 0.00017 mol cobalt tetroxide (Co3O4), 0.0005 mol manganese dioxide (MnO2), 0.00025 mol iron oxide (Fe2O3), 0.00025 mol bismuth oxide (Bi2O3) and 0.0005 mol stannous oxide (SnO) as reaction raw materials, weigh grinding balls at a ball-to-material ratio of 15:1, and ball mill at 250 rpm for 3 hours to mix them evenly.

[0050] 2) Weigh 3g of metallic sodium in an argon atmosphere glove box, place it in a sealed crucible and heat it to 300°C to obtain liquid metallic sodium. Weigh 1g of the powder obtained in step 1), add it to the liquid metallic sodium and mix thoroughly. Keep it at 300°C for 0.5 hours and then let it cool naturally.

[0051] 3) Transfer the product from step 2) to a beaker inside a glove box and add sufficient anhydrous ethanol to remove residual metallic sodium.

[0052] 4) Remove the product obtained in step 3) from the glove box, then quickly wash the product by vacuum filtration with anhydrous ethanol as the medium, and then place the product in a vacuum drying oven at 60 °C to dry it thoroughly. After drying, store the product in a glove box filled with argon gas.

[0053] The sample prepared by the above process in this embodiment is a nanostructured TiO2 / CoMnFeBiSn composite material, wherein the molar ratio of titanium dioxide to each metal element in the high-entropy alloy is controlled at 20:1.

[0054] Example 4 This embodiment prepares a titanium dioxide and high-entropy alloy composite material for ion batteries. The specific preparation method is as follows: 1) Weigh 0.01 mol titanium dioxide, 0.00067 mol cobalt tetroxide (Co3O4), 0.002 mol manganese dioxide (MnO2), 0.001 mol iron oxide (Fe2O3), 0.002 mol molybdenum dioxide (MoO2) and 0.002 mol nickel oxide (NiO) as reaction raw materials, weigh grinding balls at a ball-to-material ratio of 15:1, and ball mill at 250 rpm for 3 hours to mix them evenly.

[0055] 2) Weigh 3g of metallic sodium in an argon atmosphere glove box, place it in a sealed crucible and heat it to 200°C to obtain liquid metallic sodium. Weigh 1g of the powder obtained in step 1), add it to the liquid metallic sodium and mix thoroughly. Keep it at 200°C for 0.5 hours and then let it cool naturally.

[0056] 3) Transfer the product from step 2) to a beaker inside a glove box and add sufficient anhydrous ethanol to remove residual metallic sodium.

[0057] 4) Remove the product obtained in step 3) from the glove box, then quickly wash the product by vacuum filtration with anhydrous ethanol as the medium, and then place the product in a vacuum drying oven at 60 °C to dry it thoroughly. After drying, store the product in a glove box filled with argon gas.

[0058] The sample prepared by the above process in this embodiment is a nanostructured TiO2 / CoMnFeMoNi composite material, wherein the molar ratio of titanium dioxide to each metal element in the high-entropy alloy is controlled at 5:1.

[0059] Example 5 This embodiment prepares a titanium dioxide and high-entropy alloy composite material for ion batteries. The specific preparation method is as follows: 1) Weigh 0.01 mol titanium dioxide, 0.00033 mol cobalt tetroxide (Co3O4), 0.001 mol manganese dioxide (MnO2), 0.0005 mol iron oxide (Fe2O3), 0.001 mol molybdenum dioxide (MoO2) and 0.001 mol nickel oxide (NiO) as reaction raw materials, weigh grinding balls at a ball-to-material ratio of 15:1, and ball mill at 250 rpm for 3 hours to mix them evenly.

[0060] 2) Weigh 3g of metallic sodium in an argon atmosphere glove box, place it in a sealed crucible and heat it to 200°C to obtain liquid metallic sodium. Weigh 1g of the powder obtained in step 1), add it to the liquid metallic sodium and mix thoroughly. Keep it at 200°C for 1 hour and then let it cool naturally.

[0061] 3) Transfer the product from step 2) to a beaker inside a glove box and add sufficient anhydrous ethanol to remove residual metallic sodium.

[0062] 4) Remove the product obtained in step 3) from the glove box, then quickly wash the product by vacuum filtration with anhydrous ethanol as the medium, and then place the product in a vacuum drying oven at 60 °C to dry it thoroughly. After drying, store the product in a glove box filled with argon gas.

[0063] The sample prepared by the above process in this embodiment is a nanostructured TiO2 / CoMnFeMoNi composite material, wherein the molar ratio of titanium dioxide to each metal element in the high-entropy alloy is controlled at 10:1.

[0064] Example 6 This embodiment prepares a titanium dioxide and high-entropy alloy composite material for ion batteries. The specific preparation method is as follows: 1) Weigh 0.01 mol titanium dioxide, 0.00017 mol cobalt tetroxide (Co3O4), 0.0005 mol manganese dioxide (MnO2), 0.00025 mol iron oxide (Fe2O3), 0.0005 mol molybdenum dioxide (MoO2) and 0.0005 mol nickel oxide (NiO) as reaction raw materials, weigh grinding balls at a ball-to-material ratio of 15:1, and ball mill at 250 rpm for 3 hours to mix them evenly.

[0065] 2) Weigh 3g of metallic sodium in an argon atmosphere glove box, place it in a sealed crucible and heat it to 300°C to obtain liquid metallic sodium. Weigh 1g of the powder obtained in step 1), add it to the liquid metallic sodium and mix thoroughly. Keep it at 300°C for 0.5 hours and then let it cool naturally.

[0066] 3) Transfer the product from step 2) to a beaker inside a glove box and add sufficient anhydrous ethanol to remove residual metallic sodium.

[0067] 4) Remove the product obtained in step 3) from the glove box, then quickly wash the product by vacuum filtration with anhydrous ethanol as the medium, and then place the product in a vacuum drying oven at 60 °C to dry it thoroughly. After drying, store the product in a glove box filled with argon gas.

[0068] The sample prepared by the above process in this embodiment is a nanostructured TiO2 / CoMnFeMoNi composite material, wherein the molar ratio of titanium dioxide to each metal element in the high-entropy alloy is controlled at 20:1.

[0069] This invention enables the preparation of composite materials with different chemical compositions by controlling the types and contents of metal elements in high-entropy alloy precursors. In the composite materials prepared by this invention, high-entropy alloy nanoparticles are uniformly loaded on the surface of anatase phase titanium dioxide nanoparticles, effectively improving the conductivity and ion diffusion rate of the material, and exhibiting excellent electrochemical performance when applied to the anodes of lithium-ion and sodium-ion batteries.

[0070] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the invention. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the invention. Therefore, all technical solutions obtained through equivalent substitution or transformation fall within the protection scope of the present invention.

Claims

1. A method for preparing a titanium dioxide and high-entropy alloy composite material for an ionic battery, characterized by, Specifically as follows: S1: uniformly mixing titanium dioxide nanoparticles and high-entropy alloy precursor by means of ball milling to obtain a uniform composite precursor; S2: under an inert atmosphere, placing the composite precursor and sodium metal together in a sealed environment, heating to a preset temperature to perform a reduction reaction, and maintaining the temperature for a period of time; S3: under an inert atmosphere, removing residual sodium metal from the product obtained in S2, and after washing and drying the final product, obtaining a titanium dioxide and high-entropy alloy composite material for ion batteries.

2. The method of claim 1, wherein the method is characterized by: The size of the titanium dioxide nanoparticles is 5-100 nm, and the crystal form is anatase.

3. The method of claim 1, wherein the method is characterized by: The high-entropy alloy comprises at least five metal elements, including iron, manganese, cobalt, bismuth, tin, titanium, vanadium, chromium, nickel, copper, zirconium, niobium and molybdenum; and the high-entropy alloy precursor is an oxide or chloride corresponding to the metal elements.

4. The method of claim 1, wherein the method is characterized by: In the ball milling process, the rotation speed is controlled at 200-300 rpm, the ball-to-material ratio is (10-15):1, and the ball milling time is 3-4 hours.

5. The method of claim 1, wherein the method is characterized by: The molar ratio of the titanium dioxide nanoparticles to each metal element in the high-entropy alloy precursor is uniform, and the range is (20-1):

1.

6. The method of claim 1, wherein the method is characterized by: The mass ratio of the sodium metal to the composite precursor is (1-5):

1.

7. The method of claim 1, wherein the method is characterized by: In the reduction reaction, the preset temperature is 200-400 ℃, and the holding time is 0.5-1 hour.

8. The method of claim 1, wherein the method is characterized by: The residual sodium metal is removed by anhydrous ethanol.

9. A titanium dioxide and high-entropy alloy composite material for ion batteries obtained by the preparation method of any one of claims 1-8.

10. Use of the titanium dioxide and high-entropy alloy composite material for ion batteries of claim 9 in an ion battery negative electrode material.

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