Preparation method of molybdenum disulfide nanosheet composite carbon fiber film

Abstract

The invention provides a molybdenum disulfide nanosheet composite carbon fiber film preparation method, which comprises: placing a sulfur-containing substance, molybdenum trioxide and a molybdenum sheet in a closed environment, and placing a carbon fiber film above the molybdenum sheet; generating a magnetic field in the closed environment and ensuring that the sulfur-containing substance, the molybdenum trioxide and the molybdenum sheet are arranged in the magnetic field; after reacting for a certain time, stopping the magnetic field; after cooling, the molybdenum disulfide nanosheet composite carbon fiber film can be obtained, and molybdenum disulfide nanosheets grow on the surface of the carbon fiber in situ. Compared with the existing preparation method, the preparation method disclosed by the invention is simpler in production equipment, short in reaction time and high in production speed.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of chemical preparation, in particular to a preparation method of molybdenum disulfide nanosheet / carbon fiber film. BACKGROUND

[0002] MoS2 has a layered structure similar to graphene, and single-layer or few-layer MoS2 nanomaterials exhibit excellent performance in device preparation, catalysis and energy storage. Adjacent crystal layers of MoS2 with a layered structure are connected to each other by van der Waals force, and the lattice spacing is 0.615 nm, which is significantly higher than the interlayer spacing of graphite (0.335 nm), so that MoS2 is very conducive to the embedding and extraction of guest ions, which makes MoS2 have good Li+ transmission performance. MoS2 as a new type of lithium ion battery negative electrode material has a high theoretical capacity (~669 mAh / g). However, MoS2 has a large volume change (104%) during lithium ion insertion / extraction. Compared with bulk materials, molybdenum disulfide nanosheets have shorter Li+ diffusion distance and high concentration of edge active sites, so molybdenum disulfide nanosheets have smaller volume expansion and higher reversible capacity. In addition, MoS2 generally exists in the form of 2H phase, and 2H-MoS2 as a semiconductor material has lower electronic conductivity, which also leads to poor electrode rate performance. The use of carbon materials (such as carbon nanotubes, reduced graphene oxide and carbon fibers) with better electrical conductivity to prepare MoS2 / C composite materials as negative electrode materials can improve the electronic conductivity of the electrode.

[0003] So far, a variety of molybdenum disulfide / carbon composite material preparation methods have been widely studied. The commonly used methods can be roughly divided into two categories. The first method is to mix molybdenum disulfide and carbon into a shape, and the mixed material is made into an aerogel by freeze-drying, or a mixed fiber is made by electrospinning. The second method is to mix carbon materials with molybdate and sulfide, and use hydrothermal method to grow molybdenum disulfide nanostructure on the surface of carbon materials. In general, the introduction of carbon materials not only increases the conductivity of the electrode, but also to some extent alleviates the volume expansion of molybdenum disulfide. Although a variety of molybdenum disulfide / carbon composite materials have been prepared, it is still a challenge to mass-produce high-quality few-layer molybdenum disulfide nanomaterials, and in addition, there are difficulties in the ordered combination of a large amount of molybdenum disulfide nanostructure and carbon materials. SUMMARY

[0004] In view of the above technical problems, the application provides a novel method for preparing a molybdenum disulfide nanosheet composite carbon fiber film by a dynamic magnetic field vapor deposition method. The method utilizes the characteristic that a dynamic magnetic field can directionally and rapidly transport molecules, so that a large amount of molybdenum disulfide nanosheets are rapidly in-situ grown on the carbon fiber film. In summary, the dynamic magnetic field vapor deposition method can rapidly prepare a high-quality molybdenum disulfide composite carbon fiber film, and the composite material exhibits good lithium storage and cycle performance as an independent electrode. The preparation method can be simultaneously applied to laboratory research and large-scale production in a factory.

[0005] The technical scheme of the application is as follows:

[0006] A method for preparing a molybdenum disulfide nanosheet composite carbon fiber film, comprising the following steps:

[0007] Placing sulfur-containing substances, molybdenum trioxide and molybdenum sheets in a closed environment;

[0008] Generating a magnetic field in the closed environment and ensuring that the sulfur-containing substances, molybdenum trioxide and molybdenum sheets are placed in the magnetic field;

[0009] After a certain reaction time, the magnetic field is stopped;

[0010] After cooling, a molybdenum disulfide nanosheet composite carbon fiber film is obtained, and the molybdenum disulfide nanosheets are in-situ grown on the surface of the carbon fiber.

[0011] The application uses molybdenum trioxide and sulfur-containing substances as reactants, and uses molybdenum sheets as a heat source to in-situ grow molybdenum disulfide nanosheets on a carbon fiber film in a vacuum magnetic suspension induction furnace. By utilizing the characteristic that a magnetic field can rapidly heat metal materials, a magnetic field is applied to the molybdenum sheets, and when the magnetic field passes through the molybdenum sheets, eddy currents are generated on the molybdenum sheets, the eddy currents heat the molybdenum sheets, and then heat the molybdenum trioxide and sulfur in the crucible. The molybdenum trioxide and sulfur are transported to the surface of the carbon fiber under the action of the dynamic magnetic field, and the molybdenum disulfide is rapidly grown on the carbon fiber. Finally, a molybdenum disulfide nanosheet composite carbon fiber film is obtained, and the molybdenum disulfide nanosheets are in-situ grown on the surface of the carbon fiber.

[0012] It should be noted that there are many methods for generating a magnetic field in a closed environment, for example, an electromagnetic field can be generated by using an electric current, and a magnetic field can be generated by using a magnet.

[0013] The magnetic field degree of the magnetic field is 0.001 T to 1 T.

[0014] The reaction time is 5 s to 1 h. By controlling the magnetic field strength and the reaction time, the number of layers of the molybdenum disulfide nanosheets can be adjusted.

[0015] The vacuum degree of the closed environment is less than 10 KPa. The vacuum degree of the closed environment can be achieved by cleaning the closed environment with inert gas or nitrogen.

[0016] The sulfur content of the sulfur-containing substance is not less than 0.1%.

[0017] The sulfur-containing substance is one of elemental sulfur, sulfide or disulfide or a mixture of several thereof.

[0018] In the technical solution of the present application, the sulfur-containing substance, molybdenum trioxide and molybdenum sheet can be placed non-contact (with a certain distance between the sulfur-containing substance and the molybdenum sheet), but the distance of non-contact placement cannot be too far, otherwise it will affect the generation of sulfur; the sulfur-containing substance, molybdenum trioxide and molybdenum sheet can also be placed in contact, preferably the sulfur-containing substance covers the surface of the molybdenum sheet, so that the sulfur-containing substance can be uniformly heated by the molybdenum sheet, and the generated sulfur is more easily in contact with molybdenum atoms or molybdenum trioxide molecules to produce molybdenum disulfide.

[0019] Further, the sulfur-containing substance, molybdenum trioxide and molybdenum sheet can be placed in a container and then placed in a closed environment. The container can be a crucible, such as a porcelain crucible, a quartz crucible or a graphite crucible, etc.

[0020] The beneficial effects of the present application are:

[0021] (1) Compared with the existing preparation method, the production equipment of the preparation method of the present application is simpler, the reaction time is shorter, and the production speed is faster.

[0022] (2) The product molybdenum disulfide nanosheet has good crystallinity, and the thickness of the nanosheet can be controlled by adjusting the magnetic field strength and reaction time, and the product has good physical properties.

[0023] (3) The preparation method of the present application can realize the in-situ growth of molybdenum disulfide nanosheet on the surface of carbon fiber, which is more conducive to scientific research promotion and industrialization compared with other methods. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 SEM image of molybdenum disulfide nanosheet composite carbon fiber film obtained in Example 1.

[0025] Figure 2 Partial enlargement of Figure 1

[0026] Partial enlargement of Figure 3 Figure 2

[0027] Figure 4 XRD image of molybdenum disulfide nanosheet composite carbon fiber film obtained in Example 3. DETAILED DESCRIPTION ​​

[0028] Example One

[0029] This embodiment is realized by using a magnetic levitation smelting furnace, which uses electric current to generate an electromagnetic field.

[0030] A method for preparing molybdenum disulfide nanosheets, comprising the following steps:

[0031] (1) Accurately weigh 0.753 g of sulfur, 0.02 g of molybdenum trioxide, and 5.592 g of molybdenum sheet, respectively, and place them in a crucible, then put the porcelain crucible into a vacuum magnetic levitation smelting furnace.

[0032] (2) Set the current of the vacuum magnetic levitation smelting furnace to 30 A, and set the reaction time to 60 s, at which time the generated magnetic field strength is about 0.03 T.

[0033] (3) Clean the vacuum magnetic levitation smelting furnace with nitrogen more than three times, maintain the vacuum in the furnace, and start the reaction.

[0034] (4) After the reaction is completed, the molybdenum disulfide nanosheet composite carbon fiber film can be obtained after cooling, and the molybdenum disulfide nanosheets grow in situ on the surface of the carbon fiber.

[0035] Figure 1 is an SEM image of Example One. As can be seen from Figure 1 , a large number of molybdenum disulfide nanosheets grow uniformly around the carbon fiber. Figure 2 As Figure 1 a partial enlargement, it can be seen more clearly from Figure 2 that the molybdenum disulfide nanosheets grow vertically on the surface of the carbon fiber. Figure 3 As Figure 2 a partial enlargement, it can be seen from Figure 3 that the thickness of the molybdenum disulfide nanosheets is very thin.

[0036] Example Two

[0037] (1) Accurately weigh 0.552 g of sulfur, 0.01 g of molybdenum trioxide, and 5.683 g of molybdenum sheet, respectively, and place them in a crucible, then put the porcelain crucible into a vacuum magnetic levitation smelting furnace.

[0038] (2) Set the current of the vacuum magnetic levitation smelting furnace to 30 A, and set the reaction time to 90 s, at which time the generated magnetic field strength is about 0.03 T.

[0039] (3) Clean the vacuum magnetic levitation smelting furnace with argon more than three times, maintain the vacuum in the furnace, and start the reaction;

[0040] (4) After the reaction is completed, the molybdenum disulfide nanosheet composite carbon fiber film can be obtained after cooling, and the molybdenum disulfide nanosheets grow in situ on the surface of the carbon fiber.

[0041] Example Three

[0042] (1) Accurately weigh 0.785 g of elemental sulfur, 0.02 g of molybdenum trioxide and 5.532 g of molybdenum sheet respectively, and place them in a crucible; then place the porcelain crucible into the vacuum magnetic levitation melting furnace.

[0043] (2) Set the current of the vacuum magnetic levitation melting furnace to 30 A, and set the reaction time to 120 s. At this time, the magnetic field strength generated is about 0.03 T.

[0044] (3) Clean the vacuum magnetic levitation melting furnace with argon more than three times, maintain the vacuum in the furnace, and start the reaction.

[0045] (4) After the reaction is completed, the molybdenum disulfide nanosheet composite carbon fiber film can be obtained after cooling. The molybdenum disulfide nanosheets grow in situ on the surface of the carbon fiber.

[0046] From Figure 4 is the XRD image of Example Three. The main characteristic peaks of the sample are consistent with those of 2H-MoS2, which are consistent with the XRD standard card PDF #87-2416.

[0047] Example Four

[0048] (1) Accurately weigh 1.238 g of elemental sulfur, 0.04 g of molybdenum trioxide and 5.759 g of molybdenum sheet respectively, and place them in a crucible; then place the crucible into the vacuum magnetic levitation melting furnace.

[0049] (2) Set the current of the vacuum magnetic levitation melting furnace to 1 A, and set the reaction time to 50 min. The magnetic field strength in this embodiment is 0.001 T.

[0050] (3) Clean the vacuum magnetic levitation melting furnace with nitrogen more than three times, maintain the vacuum in the furnace, and start the reaction.

[0051] (4) After the reaction is completed, the molybdenum disulfide nanosheet composite carbon fiber film can be obtained after cooling. The molybdenum disulfide nanosheets grow in situ on the surface of the carbon fiber.

[0052] Example Five

[0053] (1) Accurately weigh 0.203 g of elemental sulfur, 0.402 g of ammonium sulfide, 0.01 g of molybdenum trioxide and 5.759 g of molybdenum sheet respectively, and place them in a crucible; then place the crucible into the vacuum magnetic levitation melting furnace.

[0054] (2) Set the current of the vacuum magnetic levitation melting furnace to 100 A, and set the reaction time to 5 min. At this time, the magnetic field strength generated is about 1 T.

[0055] (3) Clean the vacuum magnetic levitation melting furnace with nitrogen more than three times, maintain the vacuum in the furnace, and start the reaction.

[0056] (4) After the reaction is completed, the molybdenum disulfide nanosheet composite carbon fiber film can be obtained after cooling, and the molybdenum disulfide nanosheet is in-situ grown on the surface of the carbon fiber.

[0057] The above-described embodiments only express several embodiments of the present application, which are described in a more specific and detailed manner, but should not be understood as a limitation on the scope of the patent of the present application. It should be noted that, for ordinary skilled persons in the art, several modifications and improvements can be made without departing from the concept of the present application, which all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the claims.

Claims

1. A method for preparing a molybdenum disulfide nanosheet composite carbon fiber film, characterized in that, The method comprises the following steps: placing sulfur-containing substance, molybdenum trioxide and molybdenum sheet in a closed environment, and placing carbon fiber film above the molybdenum sheet; generating a magnetic field in the closed environment and ensuring that the sulfur-containing substance, molybdenum trioxide and molybdenum sheet are placed in the magnetic field; stopping the magnetic field after a certain reaction time; after cooling, a molybdenum disulfide nanosheet composite carbon fiber film is obtained, and molybdenum disulfide nanosheets grow in situ on the surface of carbon fibers.

2. The method of claim 1, wherein, The magnetic field strength of the magnetic field is 0.001T to 1T.

3. The method of claim 1, wherein, The reaction time is 5s to 1h.

4. The method of claim 1, wherein, The vacuum degree of the closed environment is less than 10KPa.

5. The method according to any one of claims 1 to 4, characterized in that, The sulfur content of the sulfur-containing substance is not less than 0.1%.

6. The method of claim 5, wherein, The sulfur-containing substance is one or a mixture of several of elemental sulfur, sulfide or disulfide.

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