A calabash-shaped niobium trisulfide / tungsten disulfide composite material, a preparation method thereof, and an application thereof in potassium ion batteries

Abstract

The present invention discloses a gourd-shaped niobium trisulfide / tungsten disulfide composite material, a preparation method thereof, and an application thereof in potassium ion batteries, belonging to the technical field of functional material synthesis. Tungsten hexachloride is added to an ethanol solution, thioacetamide is added, and then niobium pentachloride is added. After hydrothermal reaction, washing, and drying, a gourd-shaped niobium trisulfide / tungsten disulfide composite material is obtained; the morphological structure of the intertwined short fibers and the gourd-shaped structure, as the channels for metal ions to enter and exit, is conducive to the storage and transmission of metal ions; the combination of tungsten disulfide and niobium trisulfide improves the electrochemical performance of tungsten disulfide, well buffers the conductivity of the electrode material, and effectively improves the capacity of the tungsten disulfide negative electrode material. The one-step template-free hydrothermal reaction has a low synthesis temperature, a simple synthesis path, is easy to control, efficient, low-cost, and does not require large equipment and harsh reaction conditions. The whole reaction has a high yield and is environmentally friendly, and the product does not require post-treatment, being suitable for large-scale production.

Description

Technical Field

[0001] The present invention belongs to the technical field of functional material synthesis, and particularly relates to a calabash-shaped niobium trisulfide / tungsten disulfide composite material, a preparation method thereof, and an application thereof in potassium ion batteries. Background Art

[0002] In the process of industrialization, non-renewable energy sources such as coal and petroleum are continuously consumed. Environmental pollution problems arise along with the use of fossil energy, such as greenhouse gases and acid rain. Therefore, green and environmentally friendly clean energy has attracted people's attention. However, green energy sources such as wind energy and solar energy have problems in resource utilization in terms of time and space, such as weak continuity and uneven distribution, resulting in unstable energy supply. Based on these problems, the utilization and storage of energy have become more important. Secondary battery energy storage technology has received extensive attention due to its advantages such as low cost, high energy utilization rate, and convenient use. Lithium ion batteries have been widely used in electrical equipment fields such as mobile phones, computers, and electric vehicles due to their advantages such as high capacity and good performance. However, with the advent of the era of smart electric grids, due to the scarcity of lithium resources on the earth, it is difficult to meet the large-scale market demand. To solve this problem, it is urgent to develop new secondary battery energy storage technology. Potassium ion batteries (KIBs) have attracted much attention due to their rich resources and low cost.

[0003] Some sulfides and oxides of transition metals have become potential anode materials for potassium ion batteries because their internal layered structures can provide channels for the insertion and extraction of ions. Tungsten disulfide (WS2) is a typical transition metal sulfide with a sandwich structure of S-W-S sandwich layers as the basic unit. In the sandwich layer, each W atom is covalently bonded to 6 S atoms, showing a triangular pyramid column shape. The graphene-like layered structure of WS2 is bonded by a relatively weak van der Waals force. Due to this van der Waals force between layers, the insertion of metal ions such as lithium ions, sodium ions, and potassium ions becomes possible. However, WS2 also has the disadvantages of poor conductivity and easy volume expansion during the charge and discharge process, which limits its wide application in practice.

[0004] Aiming at the problems of poor conductivity of tungsten disulfide and easy volume expansion during the charge and discharge process, it is urgent to conduct modification research on it to enhance its structural stability, relieve the volume expansion of tungsten disulfide during the charge and discharge process, and enhance its conductivity. Summary of the Invention

[0005] In order to overcome the above-mentioned disadvantages of the prior art, the purpose of the present invention is to provide a preparation method of a niobium trisulfide / tungsten disulfide composite material to solve the technical problems of poor conductivity of tungsten disulfide and easy volume expansion during the charge and discharge process in the prior art.

[0006] To achieve the above purpose, the present invention adopts the following technical solutions:

[0007] The present invention discloses a preparation method of a gourd-shaped niobium trisulfide / tungsten disulfide composite material, comprising:

[0008] Adding tungsten hexachloride into an ethanol solution, stirring evenly, adding thioacetamide and stirring evenly, then adding niobium pentachloride and stirring evenly. After hydrothermal reaction, washing and drying are carried out to obtain the gourd-shaped niobium trisulfide / tungsten disulfide composite material.

[0009] Preferably, the mass ratio of tungsten hexachloride: thioacetamide: niobium pentachloride is (0.44 - 0.55):(0.8 - 1.1):(0.025 - 0.04).

[0010] Preferably, the stirring time is 10 - 30 min.

[0011] Preferably, the stirring speed is 400 - 600 r / min.

[0012] Preferably, the temperature of the hydrothermal reaction is 160 - 250 °C.

[0013] Preferably, the time of the hydrothermal reaction is 1 - 8 h.

[0014] Preferably, the drying temperature is 60 - 80 °C.

[0015] Preferably, the drying time is 8 - 24 h.

[0016] The present invention also discloses the gourd-shaped niobium trisulfide / tungsten disulfide composite material prepared by the above preparation method.

[0017] The present invention also discloses the application of the above gourd-shaped niobium trisulfide / tungsten disulfide composite material in the preparation of a negative electrode material for a potassium ion battery.

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

[0019] The present invention discloses a preparation method of a gourd-shaped niobium trisulfide / tungsten disulfide composite material. Tungsten hexachloride is added to an ethanol solution and stirred evenly to introduce a tungsten source, which is evenly dispersed in the solvent. Thioacetamide is added and stirred evenly to introduce a sulfur source, which is evenly dispersed in the solvent. Then niobium pentachloride is added and stirred evenly to introduce a niobium source, which is evenly dispersed in the solvent. Using tungsten hexachloride, thioacetamide and niobium pentachloride as raw materials, they are all common raw materials, cheap, easily available and low in cost. By compounding tungsten disulfide with niobium trisulfide, the structural stability of tungsten disulfide is enhanced, the volume expansion during the charge and discharge process of tungsten disulfide is effectively alleviated, and the conductivity of tungsten disulfide is enhanced. After hydrothermal reaction, it is washed and dried to obtain a gourd-shaped niobium trisulfide / tungsten disulfide composite material. The final composite structure is directly synthesized by a one-step template-free hydrothermal reaction, so it has a low synthesis temperature, a simple synthesis route, is easy to control, efficient, low-cost and does not require large equipment and harsh reaction conditions. The whole reaction has a high yield and is environmentally friendly, and the product does not require post-treatment and is suitable for large-scale production. Compounding tungsten disulfide with niobium trisulfide improves the electrochemical performance of the tungsten disulfide material. On the one hand, compounding tungsten disulfide with niobium trisulfide well buffers the conductivity of the electrode material. On the other hand, compounding tungsten disulfide with niobium trisulfide can effectively improve the capacity of the tungsten disulfide negative electrode material.

[0020] Furthermore, the present invention strictly and synergistically controls parameters such as the concentration and ratio of the tungsten source, niobium source, sulfur source, reaction temperature, reaction time, filling ratio, etc., so as to form a composite structure with a morphology of intertwined short fibers and gourd-shaped structures; the addition amount plays a key role in the formation of the morphology structure of intertwined short fibers and gourd-shaped structures. Too much or too little introduction is not conducive to the growth of the morphology of intertwined short fibers and gourd-shaped structures, and thus an excellent composite structure cannot be obtained.

[0021] The present invention also discloses a gourd-shaped niobium trisulfide / tungsten disulfide composite material prepared by the above preparation method. The gourd-shaped niobium trisulfide / tungsten disulfide composite material has a unique composite structure, in which the morphology structure of intertwined short fibers and gourd-shaped structures, as a channel for metal ions to enter and exit, is very conducive to the storage and transmission of metal ions in tungsten disulfide. The chemical bonding effect between tungsten disulfide and niobium trisulfide can not only further stabilize the structure, but also accelerate the charge transfer between them. Under the synergistic effect of the above structural advantages, the niobium trisulfide / tungsten disulfide composite electrode can exhibit excellent cycle performance and rate performance.

[0022] The present invention also discloses the application of the above-mentioned gourd-shaped niobium trisulfide / tungsten disulfide composite material in the preparation of the anode material for potassium ion batteries. The gourd-shaped niobium trisulfide / tungsten disulfide composite material has a larger specific surface area, provides more active sites, and is beneficial to ion storage. By studying the influence of the material structure on the potassium electrochemical storage process and establishing the structure-activity mechanism of the material during potassium storage, it can provide a reference basis for expanding the anode material system and improving the performance of potassium ion batteries. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is the XRD pattern of the gourd-shaped niobium trisulfide / tungsten disulfide composite material disclosed in Example 3 of the present invention;

[0024] Figure 2 is the SEM pattern of the gourd-shaped niobium trisulfide / tungsten disulfide composite material disclosed in Example 3 of the present invention;

[0025] Figure 3 is the cycle performance graph of the gourd-shaped niobium trisulfide / tungsten disulfide composite material disclosed in Example 3 of the present invention;

[0026] Figure 4 is the rate performance graph of the gourd-shaped niobium trisulfide / tungsten disulfide composite material disclosed in Example 3 of the present invention in a potassium ion battery. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] In order to enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of the present invention.

[0028] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and do not necessarily need to be used to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so that the embodiments of the present invention described herein can be implemented in an order different from those illustrated or described herein. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device comprising a series of steps or units does not necessarily need to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0029] The present invention will be further described in detail below in conjunction with the accompanying drawings:

[0030] The present invention discloses a preparation method of a gourd-shaped niobium trisulfide / tungsten disulfide composite material, comprising the following steps:

[0031] 1) Take a certain mass of analytical pure tungsten hexachloride and add it to a beaker containing 50 mL of ethanol solution, stir for 10 - 30 min, and the rotation speed is 400 - 600 r / min;

[0032] 2) Weigh a certain mass of thioacetamide and add it to the above solution, stir for 10 - 30 min;

[0033] 3) Then add a certain mass of niobium pentachloride to the above solution, stir for 10 - 30 min to make it evenly dispersed in the solution;

[0034] 4) Transfer the mixed solution into a reaction kettle, seal it and place it in a homogeneous reactor, and react at 160 - 250 °C for 1 - 8 h;

[0035] 5) After the reaction is completed, take out the product, wash it, and dry it in a vacuum oven at 60 - 80 °C for 8 - 24 h. The obtained product is the gourd-shaped niobium trisulfide / tungsten disulfide composite material.

[0036] Among them: the mass ratio of tungsten hexachloride: thioacetamide: niobium pentachloride is (0.44 - 0.55):(0.8 - 1.1):(0.025 - 0.04).

[0037] Example 1

[0038] A preparation method of a gourd-shaped niobium trisulfide / tungsten disulfide composite material, comprising the following steps:

[0039] 1) Take 0.4462 g of analytical pure tungsten hexachloride and add it to a beaker containing 50 mL of ethanol solution, stir for 10 min, and the rotation speed is 600 r / min;

[0040] 2) Weigh 0.8444 g of thioacetamide and add it to the above solution, stir for 10 min;

[0041] 3) Then add 0.0250 g of niobium pentachloride to the above solution, stir for 10 min to make it evenly dispersed in the solution; <°

[0042] 4) Transfer the mixed solution into a reaction kettle, seal it and place it in a homogeneous reactor, and react at 160 °C for 8 h;

[0043] 5) After the reaction is completed, take out the product, wash it, and dry it in a vacuum oven at 60 °C for 24 h. The obtained product is the gourd-shaped niobium trisulfide / tungsten disulfide composite material.

[0044] Example 2

[0045] A preparation method of a gourd-shaped niobium trisulfide / tungsten disulfide composite material, comprising the following steps:

[0046] 1) Take 0.4738 g of analytically pure tungsten hexachloride and add it to a beaker containing 50 mL of an ethanol solution, stir for 15 min, and the rotation speed is 500 r / min;

[0047] 2) Weigh 0.9534 g of thioacetamide and add it to the above solution, stir for 15 min;

[0048] 3) Then add 0.029 g of niobium pentachloride to the above solution, stir for 15 min to uniformly disperse it in the solution;

[0049] 4) Transfer the mixed solution into a reaction kettle, seal it and place it in a homogeneous reactor, and react at 180 °C for 6 h;

[0050] 5) After the reaction is completed, take out the product, wash it, and dry it in a vacuum oven at 70 °C for 16 h. The obtained product is the gourd-shaped niobium trisulfide / tungsten disulfide composite material.

[0051] Example 3

[0052] A preparation method of a gourd-shaped niobium trisulfide / tungsten disulfide composite material, comprising the following steps:

[0053] 1) Take 0.4958 g of analytically pure tungsten hexachloride and add it to a beaker containing 50 mL of an ethanol solution, stir for 20 min, and the rotation speed is 500 r / min;

[0054] 2) Weigh 0.9735 g of thioacetamide and add it to the above solution, stir for 20 min;

[0055] 3) Then add 0.034 g of niobium pentachloride to the above solution, stir for 20 min to uniformly disperse it in the solution;

[0056] 4) Transfer the mixed solution into a reaction kettle, seal it and place it in a homogeneous reactor, and react at 200 °C for 4 h;

[0057] 5) After the reaction is completed, take out the product, wash it, and dry it in a vacuum oven at 70 °C for 12 h. The obtained product is the gourd-shaped niobium trisulfide / tungsten disulfide composite material.

[0058] Example 4

[0059] A preparation method of a gourd-shaped niobium trisulfide / tungsten disulfide composite material, comprising the following steps:

[0060] 1) Take 0.5237 g of analytically pure tungsten hexachloride and add it to a beaker containing 50 mL of an ethanol solution, stir for 30 min, and the rotation speed is 400 r / min;

[0061] 2) Weigh 0.9931 g of thioacetamide and add it to the above solution, and stir for 30 min;

[0062] 3) Then add 0.036 g of niobium pentachloride to the above solution, and stir for 30 min to uniformly disperse it in the solution;

[0063] 4) Transfer the mixed solution into a reaction kettle, seal it and place it in a homogeneous reactor, and react at 220 °C for 2 h;

[0064] 5) After the reaction is completed, take out the product, wash it, and dry it in a vacuum oven at 70 °C for 12 h. The obtained product is the gourd-shaped niobium trisulfide / tungsten disulfide composite material.

[0065] Example 5

[0066] A preparation method of a gourd-shaped niobium trisulfide / tungsten disulfide composite material includes the following steps:

[0067] 1) Take 0.5454 g of analytical pure tungsten hexachloride and add it to a beaker containing 50 mL of ethanol solution, and stir for 10 min at a rotation speed of 600 r / min;

[0068] 2) Weigh 1.0927 g of thioacetamide and add it to the above solution, and stir for 10 min;

[0069] 3) Then add 0.0400 g of niobium pentachloride to the above solution, and stir for 10 min to uniformly disperse it in the solution;

[0070] 4) Transfer the mixed solution into a reaction kettle, seal it and place it in a homogeneous reactor, and react at 250 °C for 1 h;

[0071] 5) After the reaction is completed, take out the product, wash it, and dry it in a vacuum oven at 80 °C for 8 h. The obtained product is the gourd-shaped niobium trisulfide / tungsten disulfide composite material.

[0072] See Figure 1 The XRD pattern of the gourd-shaped niobium trisulfide / tungsten disulfide composite material disclosed in Example 3 of the present invention; the product obtained in Example 3 was analyzed using a Rigaku D / max2000PC X-ray diffractometer, and the XRD of the obtained product is shown in Figure 1 , as can be seen from the figure, the diffraction peaks of the gourd-shaped niobium trisulfide / tungsten disulfide composite material prepared in Example 3 of the present invention are consistent with the diffraction peaks of the niobium trisulfide and tungsten disulfide standard cards, indicating that the niobium trisulfide / tungsten disulfide composite material is successfully synthesized, and the peaks are relatively sharp, indicating that its crystallinity is good.

[0073] See Figure 2SEM image of the gourd-shaped niobium trisulfide / tungsten disulfide composite material disclosed in Example 3 of the present invention; The product obtained in Example 3 was observed under a scanning electron microscope. As can be seen from the figure, the gourd-shaped niobium trisulfide / tungsten disulfide composite material prepared by the present invention exhibits a morphology in which short fibers are intertwined with the gourd-shaped structure, has a large specific surface area, can provide more active sites, and is beneficial to the storage of ions.

[0074] The obtained product was assembled into a button-type potassium ion battery. The specific encapsulation steps are as follows: The active powder, conductive agent (Super P), and binder (carboxymethyl cellulose CMC) were ground evenly according to a mass ratio of 7:2:1, made into a slurry, and the slurry was evenly coated on the copper foil with a film applicator, and then dried in a vacuum drying oven at 80 °C for 12 h. Then, the electrode sheet was assembled into a potassium ion half-cell, and a Neware electrochemical workstation was used to perform a constant current charge-discharge test on the battery. The test voltage was 0.01 - 3.0 V.

[0075] See Figure 3 It is the cycle performance graph of the potassium ion battery of the gourd-shaped niobium trisulfide / tungsten disulfide composite material disclosed in Example 3 of the present invention. As can be seen from the figure, the battery exhibits a capacity of about 200 mAh / g at a current density of 100 mA / g, and the capacity does not show a significant decay after 120 cycles. However, the capacity of pure tungsten disulfide starts to decay significantly after 30 cycles and approaches zero after 120 cycles. It can be seen that its cycle performance has been greatly improved.

[0076] See Figure 4 It is the rate performance graph of the gourd-shaped niobium trisulfide / tungsten disulfide composite material in the potassium ion battery disclosed in Example 3 of the present invention; As can be seen from the figure, compared with pure tungsten disulfide, the gourd-shaped niobium trisulfide / tungsten disulfide composite material has a higher capacity and more stable performance at current densities of 0.1 A / g, 0.2 A / g, 0.5 A / g, 1 A / g, 2 A / g, and 5 A / g respectively.

[0077] The above content is only to illustrate the technical idea of the present invention and cannot be used to limit the protection scope of the present invention. Any modification made on the basis of the technical solution according to the technical idea proposed by the present invention falls within the protection scope of the claims of the present invention.

Claims

1. A method for preparing a gourd-shaped niobium trisulfide / tungsten disulfide composite material, characterized in that: include: Tungsten hexachloride is added to an ethanol solution and stirred evenly. Thioacetamide is added and stirred evenly. Niobium pentachloride is then added and stirred evenly. After hydrothermal reaction, the mixture is washed and dried to obtain a gourd-shaped niobium trisulfide / tungsten disulfide composite material. The mass ratio of tungsten hexachloride: thioacetamide: niobium pentachloride is (0.44-0.55): (0.8-1.1): (0.025-0.04); The temperature of the hydrothermal reaction is 160-250° C.; the time of the hydrothermal reaction is 1-8 h.

2. The method for preparing the gourd-shaped niobium trisulfide / tungsten disulfide composite material according to claim 1, characterized in that: The stirring time is 10 to 30 minutes.

3. The method for preparing the gourd-shaped niobium trisulfide / tungsten disulfide composite material according to claim 1, wherein: The stirring speed is 400-600 r / min.

4. The method for preparing the gourd-shaped niobium trisulfide / tungsten disulfide composite material according to claim 1, wherein: The drying temperature is 60-80°C.

5. The method for preparing the gourd-shaped niobium trisulfide / tungsten disulfide composite material according to claim 1, wherein: The drying time is 8~24 hours.

6. A gourd-shaped niobium trisulfide / tungsten disulfide composite material prepared by the preparation method according to any one of claims 1 to 5.

7. Use of the gourd-shaped niobium trisulfide / tungsten disulfide composite material according to claim 6 in preparing a negative electrode material for potassium ion batteries.

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