Amorphous high-entropy sulfide for positive electrode of aluminum ion battery as well as preparation method and application of amorphous high-entropy sulfide

Abstract

The invention provides an amorphous high-entropy sulfide for an aluminum ion battery positive electrode and a preparation method and application thereof, the chemical general formula of the amorphous high-entropy sulfide is MS4, M is selected from at least five metal elements of Li, Mo, Ni, Cu, Mn, W, Ti, Nb, Zr, Zn and La, and at least comprises Mo, Cu, Ti and Nb. The preparation method comprises the following steps: S1, burdening; S2, preparing different types of monometal sulfide precursors by high-energy ball milling; and S3, preparing the amorphous high-entropy sulfide by high-energy ball milling. The high-entropy sulfide prepared by the method is in an amorphous state, and when the high-entropy sulfide is used as the aluminum ion battery positive electrode material, the problems that the positive electrode material in the prior art is insufficient in aluminum ion adsorption, low in storage capacity, complex in preparation condition, difficult to produce on a large scale and the like can be solved. The obtained aluminum ion battery shows good electrochemical performance and has an extremely high commercial application prospect.

Description

Technical Field

[0001] The present invention belongs to the technical field of aluminum ion batteries, and in particular relates to an amorphous high entropy sulfide for an aluminum ion battery positive electrode and a preparation method and application thereof. Background Art

[0002] At a time when the global energy landscape is accelerating its transformation, the development of energy storage technology has become increasingly important and urgent. Nowadays, there are many new energy storage technologies, including metal ion batteries (lithium batteries, sodium batteries, zinc batteries, magnesium batteries, and aluminum batteries, etc.), flow batteries, and supercapacitors. Among them, obtaining electrochemical systems with high energy density, high safety, and low cost remains a major challenge for future large-scale energy storage.

[0003] In this context, due to the high capacity of aluminum (8046 mAh cm -3 ), inherent safety, low cost and abundant element reserves, aluminum-ion batteries have good development prospects in large-scale energy storage systems. However, traditional aluminum-ion batteries face a series of key problems that hinder their practical application. On the one hand, aluminum ions have strong interactions with cations in the electrolyte, and aluminum ions need to overcome a high desolvation energy barrier before entering the host material; on the other hand, the single-electron transfer mode of traditional cationic redox chemistry delays local charge compensation, triggers electrochemical relaxation and electrode polarization, and reduces battery energy density. At the same time, the strong Coulomb force between traditional electrode materials and high-charge-density aluminum ions can easily cause lattice distortion and structural collapse, resulting in fewer storage sites and accelerated battery failure.

[0004] High entropy materials contain a variety of metal elements, usually at least five elements. They have the advantages of huge component adjustment space, unique entropy effect and adjustable material properties, providing a rich combination for adjusting electronic and geometric structures to optimize catalytic activity. Chinese invention patent CN113353996B discloses a high-entropy conversion type sodium ion battery electrode material and its preparation method to solve the technical problems of short cycle life and low first coulomb efficiency when the existing conversion reaction type materials are used as sodium ion battery electrodes. Chinese invention patent CN114883522A discloses a high-entropy multi-layered transition metal oxide positive electrode material and its preparation method and application. A high-entropy multi-layered potassium ion battery positive electrode energy storage material is designed by five-element doping, in which a main metal element provides the main capacity contribution, and other atoms are used as inactive materials to stabilize the material structure, so as to solve the problems of complex phase change, severe capacity attenuation and low rate performance of the manganese-based layered metal oxide positive electrode in the prior art.

[0005] In the family of high entropy materials, amorphous high entropy sulfides have important potential value in the research of positive electrode materials for aluminum ion batteries due to their unique structural and performance characteristics. Compared with crystalline materials, amorphous materials have short-range ordered and long-range disordered structural characteristics, which may give them unique advantages in the process of ion storage and transmission. For example, amorphous structures can provide more ion diffusion channels, which is conducive to the rapid insertion and extraction of aluminum ions, thereby improving the rate performance of the battery. However, the research on amorphous high entropy sulfides is still in its infancy. In terms of preparation methods, the existing technology has many shortcomings. Most preparation methods are difficult to accurately control the elemental composition and microstructure, resulting in poor repeatability and stability of material performance. The preparation process is often complicated and cumbersome, requiring harsh reaction conditions, such as high temperature and high pressure reaction processes, which not only increases the production cost, but also limits the feasibility of large-scale production. Therefore, the development of amorphous high entropy sulfides and their preparation technology for aluminum ion battery positive electrodes is of great significance, and is of great significance to promoting the application of high-performance rechargeable aluminum batteries. Summary of the invention

[0006] In view of this, the present invention aims to propose an amorphous high entropy sulfide for the positive electrode of an aluminum ion battery and a preparation method and application thereof. By using amorphous high entropy sulfide as the positive electrode material of the aluminum ion battery, the problems of insufficient adsorption of aluminum ions by the positive electrode material in the prior art, low storage capacity, complex preparation conditions, and difficulty in large-scale production are solved.

[0007] To achieve the above object, the technical solution of the present invention is achieved as follows:

[0008] In a first aspect, the present invention provides an amorphous high entropy sulfide for an aluminum ion battery positive electrode, wherein the amorphous high entropy sulfide has a chemical formula of MS 4 , M is selected from at least five metal elements of Li, Mo, Ni, Cu, Mn, W, Ti, Nb, Zr, Zn, and La, and at least includes Mo, Cu, Ti, and Nb; the ratio of the sum of the molar numbers of the metal elements in the amorphous high entropy sulfide to the molar number of the S element is 1:4; the metal elements in the amorphous high entropy sulfide, except Ti and Nb, are in an equimolar ratio, wherein the molar ratio of Ti to Cu is 2:1, and the molar ratio of Ti to Nb is equimolar.

[0009] The second aspect of the present invention provides a method for preparing an amorphous high entropy sulfide for an aluminum ion battery positive electrode, wherein the chemical formula of the amorphous high entropy sulfide is MS 4 , including the following steps:

[0010] S1. Ingredients

[0011] According to the molar ratio of metal M to sulfur in the monometallic sulfide of 1:4, the required metal powder and sulfur powder are accurately weighed; the metal M is selected from at least five elements of Li, Mo, Ni, Cu, Mn, W, Ti, Nb, Zr, Zn, and La, and at least Mo, Cu, Ti, and Nb are included;

[0012] S2. Preparation of different types of monometallic sulfide precursors by solid phase method

[0013] The weighed metal powder and sulfur powder are placed in a high-energy planetary ball mill for ball milling, and the metal and sulfur elements are mechanically forced to form a monometallic sulfide precursor with a molar ratio of 1:4;

[0014] S3. Preparation of amorphous high entropy sulfide by solid phase method

[0015] According to the predetermined stoichiometric ratio of the amorphous high entropy sulfide, each single metal sulfide precursor is accurately weighed; except for Ti and Nb, each metal element in the amorphous high entropy sulfide is in an equal molar ratio, wherein the molar ratio of Ti to Cu is 2:1, and the molar ratio of Ti to Nb is the same;

[0016] The monometallic sulfide precursors are placed together in a high-energy planetary ball mill for ball milling, so that the monometallic sulfide precursors are fully mixed and reacted to obtain amorphous high-entropy sulfide.

[0017] Furthermore, in step S2, the rotation speed of the ball mill is 400-600 rpm, the diameter of the ball mill is 3-8 mm, the ball-to-material ratio is (20-40):1, and the ball milling time is 12-48 hours. During this period, mechanical force is used to promote the full reaction of the raw materials.

[0018] Furthermore, step S2 also includes product collection. After the ball milling is completed, the ball mill is transferred to a dry, dust-free glove box for product collection. The water and oxygen content in the glove box is controlled to be less than 10 ppm to prevent the sample from being damp or oxidized.

[0019] Furthermore, step S2 further includes a drying process, where the different types of monometallic sulfide precursors obtained after the product collection are transferred to a vacuum drying oven, maintained at a temperature of 40-80° C., and vacuum dried for 12-24 hours. The drying process can further remove moisture and other volatile impurities in the product, ensuring the purity of the precursor in subsequent steps.

[0020] Furthermore, in step S3, the rotation speed of the ball mill is 600-800 rpm, the diameter of the ball milling balls is 4-6 mm, the ball-to-material ratio is (25-40):1, and the ball milling time is ≥72 h.

[0021] Furthermore, the step S3 also includes a drying process, wherein the prepared amorphous high entropy sulfide is placed in a vacuum drying oven, the temperature is maintained at 40-80° C., and a vacuum drying process is performed for 12-24 hours.

[0022] A third aspect of the present invention provides an aluminum ion battery, comprising a positive electrode material, a negative electrode material and an electrolyte, wherein the positive electrode material comprises the amorphous high entropy sulfide for the positive electrode of the aluminum ion battery described in the first and second aspects.

[0023] Furthermore, the positive electrode material is a Mo sheet uniformly coated with the amorphous high entropy sulfide, Ketjen black and carboxymethyl cellulose (CMC) in a mass ratio of 6:3:1.

[0024] Furthermore, the electrolyte is AlCl 3 and 1-ethyl-3-methylimidazolium chloride (EMICl) in a mass ratio of 1:1.3; the negative electrode material is a high-purity aluminum sheet.

[0025] The amorphous high entropy sulfide proposed in the present invention is composed of multiple elements. The characteristics of this multi-component composition and the amorphous structure make it have rich chemical environment and electronic structure characteristics. The presence of multiple elements and the amorphous structure provide more diverse ion adsorption sites and charge storage mechanisms. The synergistic effect of different elements and the amorphous structure can enhance the adsorption and storage capacity of aluminum ions, which is suitable for accommodating active ions with high charge density and is an ideal material for storing aluminum ions. The aluminum ion battery proposed in the present invention selects metallic aluminum as the negative electrode of the rechargeable battery, with a typical aluminum chloride / 1-ethyl-3-methylimidazolium chloride ion liquid (AlCl 3 / EMICl) as the electrolyte.

[0026] In summary, given the high charge density characteristics of aluminum ions, traditional positive electrode materials are limited by fixed lattice spacing and are difficult to meet their diffusion and storage requirements, resulting in limited performance of aluminum ion batteries. The present invention pioneered the use of a series of amorphous high-entropy sulfides that have never been explored before as positive electrode materials, and creatively proposed a convenient and efficient method for preparing amorphous high-entropy sulfides. This preparation method focuses on the high charge density characteristics of aluminum ions and accurately fills this technical gap. The amorphous high-entropy sulfide prepared in this way not only significantly improves battery performance, but also has a simple and easy preparation method, which provides strong support for the development of aluminum ion batteries to break through technical bottlenecks and expand application scenarios, and has extremely high research significance and practical value.

[0027] Compared with the prior art, the amorphous high entropy sulfide for the positive electrode of aluminum ion battery and the preparation method thereof proposed in the present invention have the following advantages:

[0028] (1) The raw materials of the present invention are selected from common metal sulfide precursors with a molar ratio of 1:4 that are suitable for the characteristics of aluminum ions, and amorphous high-entropy sulfides are prepared by a solid phase method, thereby providing diversified adsorption sites for aluminum ions with high charge density. This is a characteristic and advantage that many traditional positive electrode materials do not have, and greatly enhances the positive electrode material's ability to adsorb and store aluminum ions;

[0029] (2) The preparation method and process conditions of the amorphous high entropy sulfide of the present invention are extremely simple and easy to implement, which is conducive to the large-scale production of positive electrode materials. By accurately setting various parameters of a high-energy planetary ball mill, including a specific ball milling speed, ball-to-material ratio, ball milling time, and a strict vacuum drying process, amorphous high entropy sulfide materials for aluminum ion battery positive electrodes can be prepared;

[0030] (3) The present invention uses amorphous high-entropy sulfide as the positive electrode material, and the aluminum ion battery prepared therefrom exhibits good electrochemical properties such as good cycle stability and specific capacity, which not only has extremely high scientific research value, but also has broad commercial application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0032] Figure 1 is (MoWCuTiNb)S in Example 1 4 XRD pattern of

[0033] Figure 2 is (MoWCuTiNb)S in Example 1 4 Transmission electron microscopy images of

[0034] Figure 3 is (MoWCuTiNb)S in Example 1 4 Selected area electron diffraction pattern of

[0035] Figure 4 is (MoWCuTiNb)S in Example 1 4 Cyclic voltammetry curve of aluminum ion battery assembled as positive electrode material;

[0036] Figure 5 is (MoWCuTiNb)S in Example 1 4 Aluminum ion batteries assembled as positive electrode materials at 0.2A g -1 Charge and discharge curves under current density;

[0037] Figure 6 is (MoWCuTiNb)S in Example 14 The cycling stability curve of the aluminum-ion battery assembled with the positive electrode material at a current density of 0.2 A g -1 ;

[0038] Figure 7 XRD pattern of (LiMoWCuTiNb)S in Example 2 4 ;

[0039] Figure 8 XRD pattern of (LiMoWCuTiNb)S in Example 2 4 Charge-discharge curve of the aluminum-ion battery assembled with the positive electrode material at a current density of 2.0 A g -1 ;

[0040] Fig. 9 XRD pattern of (MoLiCuTiNb)S in Example 3 4 ;

[0041] Fig.10 XRD pattern of (MoZnLiCuTiNb)S in Example 4 4 Charge-discharge curve of the aluminum-ion battery assembled with the positive electrode material at a current density of 0.2 A g -1 ;

[0042] Fig.11 XRD pattern of (MoWNiLiCuTiNb)S in Example 5 4 Charge-discharge curve of the aluminum-ion battery assembled with the positive electrode material at a current density of 0.2 A g -1 ;

[0043] Fig.12 XRD pattern of (MoLaCuTiNb)S in Example 6 4 Charge-discharge curve of the aluminum-ion battery assembled with the positive electrode material at a current density of 0.2 A g -1 ;

[0044] Fig.13 XRD pattern of (MoZrCuTiNb)S in Example 7 4 ;

[0045] Fig.14 XRD pattern of (MoWCuTiNb)S in Comparative Example 1 4 Charge-discharge curve of the aluminum-ion battery assembled with the positive electrode material at a current density of 2.0 A g -1 ;

[0046] Fig.15 XRD pattern of (MoWCuTiNb)S in Comparative Example 2 4 Charge-discharge curve of the aluminum-ion battery assembled with the positive electrode material at a current density of 0.2 A g -1Cyclic stability curve under current density;

[0047] Fig.16 For the (MoWCuTiNb)S in Comparative Example 3 4 The aluminum ion battery assembled as the positive electrode material is 0.1A g -1 Cyclic stability curves at different current densities. DETAILED DESCRIPTION

[0048] The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention. Unless otherwise stated, the reagents and instruments used in the embodiments of the present invention can be obtained through conventional commercial channels. Below, in conjunction with the accompanying drawings, the technical solutions in the embodiments of the present invention are clearly and completely described. It should be clearly pointed out that the described embodiments are only a part of the set of embodiments of the present invention, rather than the entire content. In the absence of conflict, the features in the embodiments of the present invention and the embodiments can be combined with each other. Based on these embodiments covered by the present invention, all other embodiments obtained by ordinary technicians of the art without paying creative work are within the protection scope of the present invention.

[0049] Example 1

[0050] This embodiment provides an amorphous high entropy sulfide for the positive electrode of an aluminum ion battery, and its chemical formula is (MoWCuTiNb)S 4 (Nominal molecular formula is MoWCuTi 2 Nb 2 S 28 ), wherein the ratio of the sum of the molar numbers of Mo, W, Cu, Ti, and Nb to the molar number of S is 1:4, and the molar ratio of Mo, W, Cu, Ti, and Nb is 1:1:1:2:2. The preparation method of the amorphous high entropy sulfide is as follows:

[0051] S1. Ingredients

[0052] The raw materials are weighed strictly according to the molar ratio of metal to sulfur in monometallic sulfide of 1:4. A high-precision analytical balance is used to accurately weigh the metal powders of Mo, W, Cu, Ti, Nb and the corresponding amount of sulfur powder of each metal powder to ensure the accuracy of weighing.

[0053] S2. Preparation of different types of monometallic sulfide precursors by solid phase method

[0054] The weighed Mo, W, Cu, Ti, and Nb metal powders and the corresponding amount of sulfur powder were placed in a high-energy planetary ball mill under the protection of a high-purity argon atmosphere. The ball diameter was 3 mm, the ball-to-material ratio was 35:1, the speed of the ball mill was set to 400 rpm, and the ball mill was turned on to start the ball milling operation. The ball milling time was set to 24 h. Through the above parameter settings and operation procedures, the components of MoS 4 , WS 4 , CuS 4 、TiS 4 and NbS 4 Various monometallic sulfide precursors.

[0055] After the ball milling is completed, the ball mill is quickly transferred to a dry, dust-free glove box for product collection operations, and the water and oxygen content in the glove box is controlled below 10 ppm.

[0056] The different types of monometallic sulfide precursors obtained after the product collection were transferred to a vacuum drying oven and vacuum dried at 40° C. for 24 hours.

[0057] S3. Preparation of amorphous high entropy sulfide by solid phase method

[0058] According to the composition elements and ratios of the target amorphous high entropy sulfide, the precise stoichiometric ratios of the various required single metal sulfide precursors are calculated. 4 About 0.277g, weigh WS 4 About 0.385g, weigh CuS 4 About 0.237g, weigh TiS 4 About 0.435g, weigh NbS 4 About 0.546g. Select a suitable high-energy planetary ball mill and equip it with corresponding ball milling balls. The ball milling ball material can be selected according to the actual situation. The ball milling ball diameter is 5mm and the ball-to-material ratio is 30:1 to ensure the ball milling effect. Set the ball mill speed to 700rpm and start the ball mill for mixed ball milling. The ball milling time is 80h to allow each monometallic sulfide precursor to be fully mixed and reacted to obtain amorphous high entropy sulfide.

[0059] After the ball milling is completed, the prepared amorphous high entropy sulfide is placed in a vacuum drying oven and vacuum dried at 40°C for 24 hours, and then the amorphous high entropy sulfide in a standby state is collected. 4 The XRD pattern of Figure 1 Its TEM image is shown in Figure 2 In addition, the selected area electron diffraction of this region is shown in Figure 3 As shown. It can be seen that the (MoWCuTiNb)S 4 It is an amorphous high entropy sulfide.

[0060] The standby amorphous high entropy sulfide is used as the positive electrode material of the aluminum ion battery to assemble the aluminum ion battery and test it. The specific method is as follows:

[0061] The obtained (MoWCuTiNb)S 4 , Ketjen black, and CMC were ground into a slurry in a mass ratio of 6:3:1, and evenly coated on a Mo sheet with a diameter of 8 mm, and dried in a vacuum oven at 60°C for 12 hours. The resulting electrode was used as the positive electrode. 3 :EMICl=1:1.3) and high-purity aluminum sheet negative electrode were assembled into aluminum ion batteries to test their electrochemical performance. 4 The cyclic voltammetry curve (CV curve) of the aluminum ion battery assembled as the positive electrode material is as follows Figure 4 Its charge and discharge curve is shown as Figure 5 The cyclic stability curve is shown in Figure 6 As shown, they all exhibited excellent electrochemical performance.

[0062] Example 2

[0063] This embodiment provides an amorphous high entropy sulfide for the positive electrode of an aluminum ion battery, and its chemical formula is (LiMoWCuTiNb)S 4 (Nominal molecular formula is LiMoWCuTi 2 Nb 2 S 32 ), wherein the ratio of the sum of the molar numbers of Li, Mo, W, Cu, Ti, and Nb to the molar number of S is 1:4, and the molar ratio of Li, Mo, W, Cu, Ti, and Nb is 1:1:1:1:2:2. The preparation method of the amorphous high entropy sulfide is similar to that of Example 1, and the parameter changes are as follows:

[0064] When preparing the monometallic sulfide precursor, the raw materials were weighed strictly according to the molar ratio of metal to sulfur in the monometallic sulfide precursor of 1:4. A ball mill with a diameter of 4 mm was selected, the ball-to-material ratio was 35:1, the speed of the ball mill was set to 400 rpm, and the ball milling time was set to 36 h. Through the above parameter settings and operation procedures, LiS 4 、MoS 4 , WS 4 , CuS 4 、TiS 4 and NbS 4 The precursors were dried in vacuum at 45°C for 24h.

[0065] According to the composition elements and ratios of the target amorphous high entropy sulfide, the precise stoichiometric ratios of various monometallic sulfide precursors are calculated, among which TiS 4 About 0.435g, accurately weigh each single metal sulfide precursor. This amorphous material (LiMoWCuTiNb)S 4 A ball mill with a diameter of 4 mm was selected, the ball-to-material ratio was set to 25:1, the ball mill speed was adjusted to 650 rpm, and the mixed ball milling was started for 96 hours, and finally the amorphous high entropy sulfide was collected. After the ball milling was completed, the prepared amorphous high entropy sulfide was placed in a vacuum drying oven, and after vacuum drying at 45°C for 24 hours, the amorphous high entropy sulfide in standby state was collected. The XRD pattern of the obtained amorphous high entropy sulfide is shown in Figure 7 shown.

[0066] Then, the obtained (LiMoWCuTiNb)S 4 According to Example 1, an aluminum ion battery was assembled and its electrochemical performance was tested. The charge and discharge curves were as follows: Figure 8 As shown, the electrochemical performance is excellent.

[0067] Example 3

[0068] This embodiment provides an amorphous high entropy sulfide for the positive electrode of an aluminum ion battery, and its chemical formula is (MoLiCuTiNb)S 4 (Nominal molecular formula is MoLiCuTi 2 Nb 2 S 28 ), wherein the ratio of the sum of the molar numbers of Mo, Li, Cu, Ti, and Nb to the molar number of S is 1:4, and the molar ratio of Mo, Li, Cu, Ti, and Nb is 1:1:1:2:2. The preparation method of the amorphous high entropy sulfide is similar to that of Example 1, and the parameter changes are as follows:

[0069] When preparing the monometallic sulfide precursor, the raw materials were weighed strictly according to the molar ratio of metal to sulfur in the monometallic sulfide precursor of 1:4. A ball mill with a diameter of 5 mm was selected, the ball-to-material ratio was 20:1, the speed of the ball mill was set to 500 rpm, and the ball milling time was set to 48 h. Through the above parameter settings and operation procedures, the components of MoS 4 ,LiS 4 , CuS 4 、TiS 4 and NbS 4 The precursors were dried in vacuum at 50°C for 20 h.

[0070] According to the composition elements and ratios of the target amorphous high entropy sulfide, the precise stoichiometric ratios of various monometallic sulfide precursors are calculated, among which TiS 4 About 0.435g, accurately weigh each single metal sulfide precursor. This amorphous material (MoLiCuTiNb)S 4 A ball mill with a diameter of 6 mm was selected, the ball-to-material ratio was set to 25:1, the ball mill speed was adjusted to 800 rpm, and the mixed ball milling was started for 90 hours, and finally the amorphous high entropy sulfide was collected. After the ball milling was completed, the prepared amorphous high entropy sulfide was placed in a vacuum drying oven, and after vacuum drying at 50°C for 20 hours, the amorphous high entropy sulfide in the standby state was collected. The XRD pattern of the obtained amorphous high entropy sulfide is shown in FIG. Fig. 9 shown.

[0071] Example 4

[0072] This embodiment provides an amorphous high entropy sulfide for the positive electrode of an aluminum ion battery, and its chemical formula is (MoZnLiCuTiNb)S 4 (Nominal molecular formula is MoZnLiCuTi 2 Nb 2 S 32 ), wherein the ratio of the sum of the molar numbers of Mo, Zn, Li, Cu, Ti, and Nb to the molar number of S is 1:4, and the molar ratio of Mo, Zn, Li, Cu, Ti, and Nb is 1:1:1:1:2:2. The preparation method of the amorphous high entropy sulfide is similar to that of Example 1, and the parameter changes are as follows:

[0073] When preparing the monometallic sulfide precursor, the raw materials were weighed strictly according to the molar ratio of metal to sulfur in the monometallic sulfide precursor of 1:4. A ball mill with a diameter of 5 mm was selected, the ball-to-material ratio was 20:1, the speed of the ball mill was set to 450 rpm, and the ball milling time was set to 48 h. Through the above parameter settings and operation procedures, the components of MoS 4 、ZnS 4 ,LiS 4 , CuS 4 、TiS 4 and NbS 4 The precursors were dried in vacuum at 55°C for 20 h.

[0074] According to the composition elements and ratios of the target amorphous high entropy sulfide, the precise stoichiometric ratios of various monometallic sulfide precursors are calculated, among which TiS 4 About 0.435g, accurately weigh each single metal sulfide precursor. This amorphous material (MoZnLiCuTiNb)S 4A ball mill with a diameter of 6 mm was selected, the ball-to-material ratio was set to 40:1, the ball mill speed was adjusted to 800 rpm, and the mixed ball milling was started for 72 hours, and finally the amorphous high entropy sulfide was collected. After the ball milling was completed, the prepared amorphous high entropy sulfide was placed in a vacuum drying oven, and after vacuum drying at 55°C for 20 hours, the amorphous high entropy sulfide in the standby state was collected.

[0075] Then, the obtained (MoZnLiCuTiNb)S 4 According to Example 1, an aluminum ion battery was assembled and its electrochemical performance was tested. The charge and discharge curves were as follows: Fig.10 As shown, the electrochemical performance is excellent.

[0076] Example 5

[0077] This embodiment provides an amorphous high entropy sulfide for the positive electrode of an aluminum ion battery, and its chemical formula is (MoWNiLiCuTiNb)S 4 (Nominal molecular formula is MoWNiLiCuTi 2 Nb 2 S 36 ), wherein the ratio of the sum of the molar numbers of Mo, W, Ni, Li, Cu, Ti, and Nb to the molar number of S is 1:4, and the molar ratio of Mo, W, Ni, Li, Cu, Ti, and Nb is 1:1:1:1:1:2:2. The preparation method of the amorphous high entropy sulfide is similar to that of Example 1, and the parameter changes are as follows:

[0078] When preparing the monometallic sulfide precursor, the raw materials were weighed strictly according to the molar ratio of metal to sulfur in the monometallic sulfide precursor of 1:4. A ball mill with a diameter of 7 mm was selected, the ball-to-material ratio was 30:1, the speed of the ball mill was set to 400 rpm, and the ball milling time was set to 36 h. Through the above parameter settings and operation procedures, the components of MoS 4 , WS 4 、NiS 4 ,LiS 4 , CuS 4 、TiS 4 and NbS 4 The precursors were dried in vacuum at 60°C for 16 h.

[0079] According to the composition elements and ratios of the target amorphous high entropy sulfide, the precise stoichiometric ratios of various monometallic sulfide precursors are calculated, among which TiS 4 About 0.435g, accurately weigh each single metal sulfide precursor. This amorphous material (MoWNiLiCuTiNb)S 4A ball mill with a diameter of 6 mm was selected, the ball-to-material ratio was set to 25:1, the ball mill speed was adjusted to 800 rpm, and the mixed ball milling was started for 90 hours, and finally the amorphous high entropy sulfide was collected. After the ball milling was completed, the prepared amorphous high entropy sulfide was placed in a vacuum drying oven, and after vacuum drying at 60°C for 16 hours, the amorphous high entropy sulfide in the standby state was collected.

[0080] Then, the obtained (MoWNiLiCuTiNb)S 4 According to Example 1, an aluminum ion battery was assembled and its electrochemical performance was tested. The charge and discharge curves were as follows: Fig.11 As shown, the electrochemical performance is excellent.

[0081] Example 6

[0082] This embodiment provides an amorphous high entropy sulfide for the positive electrode of an aluminum ion battery, and its chemical formula is (MoLaCuTiNb)S 4 (Nominal molecular formula is MoLaCuTi 2 Nb 2 S 28 ), wherein the ratio of the sum of the molar numbers of Mo, La, Cu, Ti, and Nb to the molar number of S is 1:4, and the molar ratio of Mo, La, Cu, Ti, and Nb is 1:1:1:2:2. The preparation method of the amorphous high entropy sulfide is similar to that of Example 1, and the parameter changes are as follows:

[0083] When preparing the monometallic sulfide precursor, the raw materials were weighed strictly according to the molar ratio of metal to sulfur in the monometallic sulfide precursor of 1:4. A ball mill with a diameter of 8 mm was selected, the ball-to-material ratio was 40:1, the speed of the ball mill was set to 600 rpm, and the ball milling time was set to 12 h. Through the above parameter settings and operation procedures, the components of MoS 4 , LaS 4 , CuS 4 、TiS 4 and NbS 4 The precursors were dried in vacuum at 70°C for 16 h.

[0084] According to the composition elements and ratios of the target amorphous high entropy sulfide, the precise stoichiometric ratios of various monometallic sulfide precursors are calculated, among which TiS 4 About 0.435g, accurately weigh each single metal sulfide precursor. This amorphous material (MoLaCuTiNb)S 4A ball mill with a diameter of 5 mm was selected, the ball-to-material ratio was set to 30:1, the ball mill speed was adjusted to 750 rpm, and the mixed ball milling was started for 110 hours, and finally the amorphous high entropy sulfide was collected. After the ball milling was completed, the prepared amorphous high entropy sulfide was placed in a vacuum drying oven, and after vacuum drying at 70°C for 16 hours, the amorphous high entropy sulfide in the standby state was collected.

[0085] Then, the obtained (MoLaCuTiNb)S 4 According to Example 1, an aluminum ion battery was assembled and its electrochemical performance was tested. The cycle stability curve is shown in FIG. Fig.12 As shown, the electrochemical performance is excellent.

[0086] Example 7

[0087] This embodiment provides an amorphous high entropy sulfide for the positive electrode of an aluminum ion battery, and its chemical formula is (MoZrCuTiNb)S 4 (Nominal molecular formula is MoZrCuTi 2 Nb 2 S 28 ), wherein the ratio of the sum of the molar numbers of Mo, Zr, Cu, Ti, and Nb to the molar number of S is 1:4, and the molar ratio of Mo, Zr, Cu, Ti, and Nb is 1:1:1:2:2. The preparation method of the amorphous high entropy sulfide is similar to that of Example 1, and the parameter changes are as follows:

[0088] When preparing the monometallic sulfide precursor, the raw materials were weighed strictly according to the molar ratio of metal to sulfur in the monometallic sulfide precursor of 1:4. A ball mill with a diameter of 6 mm was selected, the ball-to-material ratio was 25:1, the speed of the ball mill was set to 550 rpm, and the ball milling time was set to 48 h. Through the above parameter settings and operation procedures, the components of MoS 4 , ZrS 4 , CuS 4 、TiS 4 and NbS 4 The precursors were dried in vacuum at 80°C for 12 h.

[0089] According to the composition elements and ratios of the target amorphous high entropy sulfide, the precise stoichiometric ratios of various monometallic sulfide precursors are calculated, among which TiS 4 About 0.435g, accurately weigh each single metal sulfide precursor. This amorphous material (MoZrCuTiNb)S 4A ball mill with a diameter of 4 mm was selected, the ball-to-material ratio was set to 35:1, the ball mill speed was adjusted to 650 rpm, and the mixed ball milling was started for 90 hours, and finally the amorphous high entropy sulfide was collected. After the ball milling was completed, the prepared amorphous high entropy sulfide was placed in a vacuum drying oven, and after vacuum drying at 80°C for 12 hours, the amorphous high entropy sulfide in the standby state was collected. The XRD pattern of the obtained amorphous high entropy sulfide is shown in FIG. Fig.13 shown.

[0090] Comparative Example 1

[0091] This comparative example provides an amorphous high entropy sulfide for the positive electrode of an aluminum ion battery, and its chemical formula is (MoWCuTiNb)S 4 (Nominal molecular formula MoWCuTi 2 Nb 2 S 28 ) is the same as in Example 1. The preparation method of the amorphous high entropy sulfide is basically the same as in Example 1, except that the following parameters are changed:

[0092] S2. Preparation of different types of monometallic sulfide precursors by solid phase method

[0093] The ball-to-material ratio was set to 15:1, the speed of the ball mill was set to 300 rpm, and the ball milling time was set to 10 h.

[0094] The obtained (MoWCuTiNb)S 4 According to Example 1, an aluminum ion battery was assembled and its electrochemical performance was tested. Fig.14 Shown at 2.0A g -1 The charge and discharge curves under current density show that the discharge capacity of the aluminum ion battery decreases and the electrochemical performance deteriorates.

[0095] Comparative Example 2

[0096] This comparative example provides an amorphous high entropy sulfide for the positive electrode of an aluminum ion battery, and its chemical formula is (MoWCuTiNb)S 4 (Nominal molecular formula MoWCuTi 2 Nb 2 S 28 ) is the same as in Example 1. The preparation method of the amorphous high entropy sulfide is basically the same as in Example 1, except that the following parameters are changed:

[0097] S2. Preparation of different types of monometallic sulfide precursors by solid phase method

[0098] The ball-to-material ratio was set to 50:1 and the rotation speed of the ball mill was set to 650 rpm.

[0099] The obtained (MoWCuTiNb)S4 According to Example 1, an aluminum ion battery was assembled and its electrochemical performance was tested. Fig.15 Shown at 0.2A g -1 The cycle life test results under current density show that the discharge capacity of the aluminum ion battery is reduced and the cycle performance is deteriorated.

[0100] Comparative Example 3

[0101] This comparative example provides an amorphous high entropy sulfide for the positive electrode of an aluminum ion battery, and its chemical formula is (MoWCuTiNb)S 4 (Nominal molecular formula MoWCuTi 2 Nb 2 S 28 ) is the same as in Example 1. The preparation method of the amorphous high entropy sulfide is basically the same as in Example 1, except that the following parameters are changed:

[0102] S3. Preparation of amorphous high entropy sulfide by solid phase method

[0103] The ball-to-material ratio was set to 20:1 and the ball mill speed was set to 550 rpm.

[0104] The obtained (MoWCuTiNb)S 4 According to Example 1, an aluminum ion battery was assembled and its electrochemical performance was tested. Fig.16 Shown at 0.1A g -1 The cycle life test results under current density show that the discharge capacity of the aluminum ion battery is reduced and the long-term cycle performance drops sharply.

[0105] Comparative Example 4

[0106] This comparative example provides an amorphous high entropy sulfide for the positive electrode of an aluminum ion battery, and its chemical formula is (MoWCuTiNb)S 4 (Nominal molecular formula MoWCuTi 2 Nb 2 S 28 ) is the same as in Example 1. The preparation method of the amorphous high entropy sulfide is basically the same as in Example 1, except that the following parameters are changed:

[0107] S3. Preparation of amorphous high entropy sulfide by solid phase method

[0108] The ball milling time was set to 70 h.

[0109] The obtained (MoWCuTiNb)S 4The aluminum ion battery was assembled according to Example 1 and its electrochemical performance was tested. Its redox peak current was significantly reduced. Compared with Example 1, the peak current was reduced by more than 50%, indicating that the active substances of the electrode reaction were reduced, the electrode process kinetics were hindered, and the reaction rate was slowed down.

[0110] Comparative Example 5

[0111] This comparative example provides a high entropy sulfide for the positive electrode of an aluminum ion battery, the chemical formula of which is (MoWTiNb)S 4 (Nominal molecular formula is MoWTi 2 Nb 2 S 24 ). The preparation method of the high entropy sulfide is exactly the same as that of Example 1, wherein step S3 weighs TiS 4 About 0.435g.

[0112] The obtained (MoWTiNb)S 4 The XRD test showed that the sample test results had obvious XRD peaks, indicating that the (MoWTiNb)S prepared in this comparative example 4 Amorphous high-entropy sulfides with well-defined crystal structures have failed to synthesize.

[0113] Comparative Example 6

[0114] This comparative example provides a high entropy sulfide for the positive electrode of an aluminum ion battery, whose chemical formula is (MoWCuZrNb)S 4 (Nominal molecular formula is MoWCuZrNb 2 S 24 ). The preparation method of the high entropy sulfide is exactly the same as that of Example 1, wherein step S3 weighs CuS 4 About 0.237g.

[0115] The obtained (MoWCuZrNb)S 4 The XRD test results showed that the sample had obvious XRD peaks, indicating that the (MoWCuZrNb)S prepared in this comparative example 4 Amorphous high-entropy sulfides with well-defined crystal structures have failed to synthesize.

[0116] Comparative Example 7

[0117] This comparative example provides a high entropy sulfide for the positive electrode of an aluminum ion battery, whose chemical formula is (FeMnNiCoCu)S 4 (Nominal molecular formula is FeMnNiCoCuS 20 ). The preparation method of the high entropy sulfide is exactly the same as that of Example 1, wherein step S3 weighs CuS 4 About 0.237g.

[0118] The obtained (FeMnNiCoCu)S 4 The XRD test showed that the sample test results had obvious XRD peaks, indicating that the (FeMnNiCoCu)S prepared in this comparative example 4 Amorphous high-entropy sulfides with well-defined crystal structures have failed to synthesize.

[0119] Comparative Example 8

[0120] This comparative example provides a high entropy sulfide for the positive electrode of an aluminum ion battery, whose chemical formula is (FeCoNiCrCu)S 4 (Nominal molecular formula is FeCoNiCrCuS 20 ). The preparation method of the high entropy sulfide is exactly the same as that of Example 1, wherein step S3 weighs CuS 4 About 0.237g.

[0121] The obtained (FeCoNiCrCu)S 4 The XRD test showed that the sample test results had obvious XRD peaks, indicating that the (FeCoNiCrCu)S prepared in this comparative example 4 Amorphous high-entropy sulfides with well-defined crystal structures have failed to synthesize.

[0122] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An amorphous high entropy sulfide for an aluminum ion battery positive electrode, characterized in that: The chemical formula of the amorphous high entropy sulfide is MS4, where M is selected from at least five metal elements of Li, Mo, Ni, Cu, Mn, W, Ti, Nb, Zr, Zn, and La, and at least includes Mo, Cu, Ti, and Nb; the ratio of the sum of the molar numbers of the metal elements in the amorphous high entropy sulfide to the molar number of the S element is 1:4; except for Ti and Nb, the other metal elements in the amorphous high entropy sulfide are in an equimolar ratio, wherein the molar ratio of Ti to Cu is 2:1, and the molar ratio of Ti to Nb is equimolar.

2. A method for preparing an amorphous high entropy sulfide for an aluminum ion battery positive electrode, characterized in that: The chemical formula of the amorphous high entropy sulfide is MS4, which comprises the following steps: S1. Ingredients According to the molar ratio of metal M to sulfur in the monometallic sulfide of 1:4, the required metal powder and sulfur powder are accurately weighed; the metal M is selected from at least five elements of Li, Mo, Ni, Cu, Mn, W, Ti, Nb, Zr, Zn, and La, and at least Mo, Cu, Ti, and Nb are included; S2. Preparation of different types of monometallic sulfide precursors by solid phase method The weighed metal powder and sulfur powder are placed in a high-energy planetary ball mill for ball milling, and the metal and sulfur elements are mechanically forced to form a monometallic sulfide precursor with a molar ratio of 1:4; S3. Preparation of amorphous high entropy sulfide by solid phase method According to the predetermined stoichiometric ratio of the amorphous high entropy sulfide, each single metal sulfide precursor is accurately weighed; each metal element in the amorphous high entropy sulfide, except Ti and Nb, is in an equal molar ratio, wherein the molar ratio of Ti to Cu is 2:1, and the molar ratio of Ti to Nb is the same; The monometallic sulfide precursors are placed together in a high-energy planetary ball mill for ball milling, so that the monometallic sulfide precursors are fully mixed and reacted to obtain amorphous high-entropy sulfide.

3. The preparation method according to claim 2, characterized in that: In step S2, the rotation speed of the ball mill is 400-600 rpm, the diameter of the ball milling balls is 3-8 mm, the ball-to-material ratio is (20-40):1, and the ball milling time is 12-48 h.

4. The preparation method according to claim 2, characterized in that: The step S2 also includes product collection. After the ball milling is completed, the ball mill is transferred to a dry, dust-free glove box for product collection. The water and oxygen content in the glove box is controlled to be less than 10 ppm.

5. The preparation method according to claim 4, characterized in that: The step S2 also includes a drying process, wherein the monometallic sulfide precursor obtained after the product is collected is transferred to a vacuum drying oven, the temperature is maintained at 40-80° C., and a vacuum drying process is performed for 12-24 hours.

6. The preparation method according to claim 2, characterized in that: In step S3, the rotation speed of the ball mill is 600-800 rpm, the diameter of the ball milling balls is 4-6 mm, the ball-to-material ratio is (25-40):1, and the ball milling time is ≥72 h.

7. The preparation method according to claim 2, characterized in that: The step S3 also includes a drying process, in which the prepared amorphous high entropy sulfide is placed in a vacuum drying oven, the temperature is maintained at 40-80° C., and a vacuum drying process is performed for 12-24 hours.

8. An aluminum ion battery comprising a positive electrode material, a negative electrode material and an electrolyte, characterized in that: The positive electrode material comprises the amorphous high entropy sulfide for the positive electrode of an aluminum ion battery according to any one of claims 1 to 7.

9. The aluminum ion battery according to claim 8, characterized in that: The positive electrode material is a Mo sheet uniformly coated with the amorphous high entropy sulfide, Ketjen black and carboxymethyl cellulose in a mass ratio of 6:3:

1.

10. The aluminum ion battery according to claim 8, characterized in that: The electrolyte is a non-aqueous electrolyte composed of AlCl3 and 1-ethyl-3-methylimidazolium chloride in a mass ratio of 1:1.3; the negative electrode material is a high-purity aluminum sheet.

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