Preparation method of tungsten disulfide / graphene composite material and application thereof

Abstract

The application relates to the technical field of electrochemical materials, in particular to a preparation method of a tungsten disulfide / graphene composite material and application thereof. Based on surface modification, coprecipitation and a high-temperature kettle reaction method, tungsten salt is deposited on the surface of silicon balls modified by graphene oxide, a high-temperature sulfuration reaction is carried out, and then the tungsten disulfide / graphene composite material is obtained after being treated with an alkali solution and an acid solution in sequence. The preparation method has the characteristics of simple operation and easy mass production, meanwhile, the tungsten disulfide / graphene composite material prepared by the method has the characteristics of three-dimensional multi-level porous structure, and when the material is used as a negative electrode material of a sodium ion battery, excellent performance and wide application prospect are exhibited.

Description

Technical Field

[0001] This invention relates to the field of electrochemical materials technology, and more particularly to a method for preparing a tungsten disulfide / graphene composite material and its application. Background Technology

[0002] Tungsten disulfide is one of the most promising anode materials for sodium-ion batteries due to its unique layered structure and high theoretical specific capacity (432 mAh·g). -1 Tungsten disulfide nanosheets have attracted widespread attention from researchers (Chemical Communications. 50. 4192 (2014)). However, the layered tungsten disulfide nanosheets are bonded together by weak van der Waals forces, and during continuous charging and discharging, the nanosheets are prone to folding and stacking, leading to structural collapse and affecting battery performance. At the same time, the poor conductivity of tungsten disulfide is also one of the main factors restricting its performance.

[0003] To overcome these shortcomings, researchers have explored various nanostructure designs, including WS2 nanowires, WS2 nanosheets, WS2 nanoflowers, and WS2 nanofibers, as anode materials for sodium-ion battery systems (Electrochimica Acta. 302. 259 (2019)). Although the sodium storage capacity of tungsten disulfide has been improved to some extent, its insufficient structural strength results in poor long-term cycle stability. Graphene, as a flexible carbon material with good electrical properties and high chemical stability, is often combined with other transition metal sulfides to form various high-performance composite materials and used as electrode materials for various energy storage systems (Energy Storage Materials. 24. 22 (2020)). However, there is limited research on graphene-tungsten disulfide composite materials, and the sodium storage capacity of the reported composite materials can still be improved (Advanced Energy Materials. 6. 1601057 (2016)). Achieving excellent synergistic effects between tungsten disulfide and graphene through superior structural design and improving their sodium storage capacity remains a challenge. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing tungsten disulfide / graphene composite materials and their applications. Tungsten salt is deposited on the surface of silicon spheres modified with graphene oxide, followed by a high-temperature sulfidation reaction and subsequent treatment with alkaline and acidic solutions to obtain the tungsten disulfide / graphene composite material. This preparation method is simple to operate and easy to mass-produce. The prepared tungsten disulfide / graphene composite material has a three-dimensional hierarchical porous structure and exhibits excellent electrochemical performance as a negative electrode material for sodium-ion batteries.

[0005] To achieve the above objectives, the technical solution of this invention is as follows:

[0006] This invention provides a method for preparing a tungsten disulfide / graphene composite material, comprising the following steps:

[0007] (1) Under an inert atmosphere, the surface of the silica ball alcohol dispersion was modified with 3-aminopropyltrimethoxysilane by constant temperature reflux to obtain surface functional group modified silica balls. The surface functional group modified silica balls and graphene oxide were ultrasonically dispersed in an alcohol solution and stirred to obtain graphene oxide / silicon ball composite.

[0008] (2) Tungsten salt is deposited on the graphene oxide / silicon sphere composite obtained in step (1) by co-precipitation to obtain a precursor mixture;

[0009] (3) The precursor mixture and sulfur source obtained in step (2) are transferred to a high-temperature reactor under an inert atmosphere;

[0010] (4) Place the high-temperature reactor from step (3) into a muffle furnace and use a programmed heating method to raise the temperature to the final temperature of 300-600℃ and then keep it constant.

[0011] (5) The product obtained in step (4) is subjected to alkali treatment, washing, and drying to obtain silicon sphere / tungsten disulfide / graphene composite material.

[0012] (6) The product obtained in step (5) is subjected to acid treatment, washing, and drying to obtain tungsten disulfide / graphene composite material.

[0013] Further, in step (1), the diameter of the silicon spheres in the silicon sphere alcohol dispersion is 20-400 nm; the inert atmosphere is one or a mixture of argon, nitrogen, and helium; the reflux temperature is 50-200 °C; and the stirring time is 1-48 h.

[0014] Further, in step (2), the tungsten salt is any one of ammonium tungstate, ammonium metatungstate, ammonium tetrathiotungstate, sodium metatungstate, or sodium tungstate; the co-precipitation temperature is 25–100°C, and the time is 6–72 h.

[0015] Further, in step (3), the inert atmosphere is one or a mixture of argon, nitrogen, and helium; the sulfur source is any one of carbon disulfide, sodium sulfide, potassium sulfide, ammonium sulfide, and thioacetamide; and the mass ratio of tungsten salt to sulfur source is 1:0.5-2.

[0016] Furthermore, in step (4), the programmed temperature rise process involves raising the temperature to the endpoint temperature at a rate of 1 to 20 °C / min, with a holding time of 2 to 6 hours.

[0017] Further, in step (5), the alkali in the alkali treatment is a sodium hydroxide solution with a concentration of 1-8 mol / L or a potassium hydroxide solution with a concentration of 1-8 mol / L, the alkali treatment time is 2-6 h, the alkali treatment temperature is 60-100 °C, the drying temperature is 25-80 °C, and the drying time is 4-48 h.

[0018] Furthermore, in step (6), the acid used in the acid treatment is a hydrofluoric acid solution with a concentration of 5-20%, and the acid treatment time is 4-48 hours; the drying temperature is 25-80°C, and the drying time is 4-48 hours.

[0019] In another aspect, the present invention provides a tungsten disulfide / graphene composite material prepared by the above-mentioned preparation method, wherein the tungsten disulfide / graphene composite material has a three-dimensional hierarchical porous structure.

[0020] The present invention also provides an application of the above-mentioned tungsten disulfide / graphene composite material, wherein the composite material is used as a negative electrode material in a sodium-ion battery system.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. The tungsten disulfide / graphene composite material of the present invention has a three-dimensional hierarchical porous structure. When used as a negative electrode material for sodium-ion batteries, it ensures sufficient contact between the electrode material and the electrolyte, shortens the diffusion path of ions, and improves the sodium storage capacity of the material. The introduction of graphene improves the conductivity of the material and also enhances the cycle stability of the material in long-term charge-discharge tests.

[0023] 2. This invention directly obtains tungsten disulfide / graphene composite material through high-temperature batch reaction, without the need for additional calcination and carbonization processes, making the preparation process simple.

[0024] 3. The method of the present invention can be used to prepare large quantities of tungsten disulfide / graphene composite materials with a wide range of applications, and the resulting tungsten disulfide / graphene composite materials have potential application prospects in the field of energy storage. Attached Figure Description

[0025] Figure 1 The N2 adsorption-desorption isotherms and pore size distribution diagrams of the tungsten disulfide / graphene composite material and the tungsten disulfide material in Example 1 and Comparative Example 1 are shown.

[0026] Figure 2 This is a high-resolution scanning electron microscope (HRSEM) image of the tungsten disulfide / graphene composite material in Example 1;

[0027] Figure 3 High-resolution scanning electron microscope (HRSEM) image of tungsten disulfide material in Comparative Example 1;

[0028] Figure 4High-resolution scanning electron microscope (HRSEM) image of the graphene material in Comparative Example 2;

[0029] Figure 5 The tungsten disulfide / graphene composite material in Example 1 was tested at a voltage range of 0.01–3 V and a current density of 100 mA·g. -1 Performance graph at that time;

[0030] Figure 6 The tungsten disulfide / graphene composite material in Example 1 was tested at a voltage range of 0.01–3V and a current density of 2000 mA·g. -1 Performance graph at that time;

[0031] Figure 7 The tungsten disulfide / graphene composite material in Example 2 was tested at a voltage range of 0.01–3 V and a current density of 2000 mA·g. -1 Performance graph at that time;

[0032] Figure 8 The tungsten disulfide / graphene composite material in Example 2 was tested at a voltage range of 0.01–3 V and a current density of 100 mA·g. -1 Performance graph at that time;

[0033] Figure 9 For Comparative Example 1, the tungsten disulfide material was tested in a voltage range of 0.01–3 V and a current density of 100 mA·g. -1 Performance graph at that time;

[0034] Figure 10 For comparative example 2, the graphene material was tested in a voltage range of 0.01–3 V and a current density of 100 mA·g. -1 Performance graph at that time. Detailed Implementation

[0035] The entire material preparation process will be described in detail below through examples.

[0036] Unless otherwise specified, the materials used in the embodiments of the present invention can be obtained commercially or prepared according to conventional methods known to those skilled in the art.

[0037] (1) Add silicon spheres to ethanol and ultrasonically disperse for 30-45 min to obtain silicon sphere ethanol dispersion. Add 3-aminopropyltrimethoxysilane and reflux at 50-200℃ under an inert atmosphere. After reflux, cool to room temperature, centrifuge and wash to obtain silicon spheres modified with surface functional groups. Ultrasonically disperse the silicon spheres modified with surface functional groups and graphene oxide in ethanol for 30-45 min, stir at room temperature for 1-48 h, centrifuge and wash to obtain graphene oxide / silicon sphere composite.

[0038] (2) Dissolve and disperse the tungsten salt and the graphene oxide / silicon sphere composite obtained in step (1) in deionized water, stir at 25-100°C for 6-72 h until the solvent is completely evaporated, and then transfer to an oven to dry to obtain a precursor mixture;

[0039] (3) Under the protection of an inert atmosphere, the precursor mixture and sulfur source obtained in step (2) are transferred to a high-temperature reactor and sealed.

[0040] (4) Place the reactor from step (3) in a muffle furnace, and heat it to 300-600℃ and keep it at that temperature for 2-6 hours.

[0041] (5) Treat the sample obtained in step (4) with an alkaline solution at a temperature of 60-100℃ for 2-6 hours. Filter the solution and wash it with water and ethanol several times until the filtrate is neutral. Dry the solution at 25-80℃ for 4-48 hours.

[0042] (6) Treat the sample obtained in step (5) with acid solution for 4-48 hours to remove the silicon balls, filter, wash with water and ethanol multiple times until the filtrate is neutral, and dry at 25-80℃ for 4-48 hours to obtain tungsten disulfide / graphene composite material with a three-dimensional multi-level porous structure.

[0043] In step (1), the inert atmosphere is preferably high-purity argon; the reflux temperature is preferably 100-120℃; and the stirring time is preferably 12-24h.

[0044] In step (2), the drying temperature is preferably 60-80℃.

[0045] In step (3), the inert atmosphere is preferably high-purity argon.

[0046] In step (4), the preferred temperature ramp rate is 10-15℃ / min; the preferred endpoint temperature is 400℃; and the preferred isothermal time is 4h.

[0047] In step (5), the alkaline solution is preferably a 4-6 mol / L NaOH solution; the alkaline treatment temperature is preferably 60℃, and the treatment time is preferably 3h.

[0048] In step (6), the acid solution is preferably a hydrofluoric acid solution with a mass fraction of 10%, and the acid treatment time is preferably 12h.

[0049] Example 1

[0050] (1) 1.6 g of silicon spheres with a diameter of 100 nm were ultrasonically dispersed in 200 mL of ethanol. Under an argon atmosphere, 4 mL of 3-aminopropyltrimethoxysilane was added and refluxed at 120 °C for 5 h. After reflux, the mixture was cooled to room temperature, centrifuged, washed, and then ultrasonically dispersed together with 150 mg of graphene oxide in 200 mL of ethanol. After stirring at room temperature for 12 h, the mixture was centrifuged and washed to obtain the graphene oxide / silicon sphere composite.

[0051] (2) 300 mg sodium tungstate and graphene oxide / silicon sphere composite were ultrasonically dispersed in 50 mL of deionized water, stirred at room temperature until the solvent was completely evaporated, transferred to an oven and dried at 80 °C for 8 h to obtain a precursor mixture;

[0052] (3) The precursor mixture and 10 mL of CS2 were sealed in a high-temperature reactor under an argon atmosphere;

[0053] (4) Transfer the high-temperature reactor to a muffle furnace and heat it to 400°C at a heating rate of 10°C / min and keep it at that temperature for 4 hours.

[0054] (5) Treat the sample obtained in step (4) with 6 mol / L sodium hydroxide solution for 3 h at a temperature of 60 °C. After treatment, filter the sample and wash it with water and ethanol several times until the filtrate is neutral. Then place it in a drying oven at 80 °C for 12 h.

[0055] (6) The sample obtained in step (5) was treated with a 10% hydrofluoric acid solution for 12 hours. After treatment, the sample was filtered and washed repeatedly with water and ethanol until the filtrate was neutral. The washed sample was placed in a forced-air drying oven and dried at 80°C for 12 hours to obtain the tungsten disulfide / graphene composite material.

[0056] N2 adsorption-desorption experiment (see...) Figure 1 This indicates that the obtained tungsten disulfide / graphene composite material has pores of different sizes, as shown in the high-resolution scanning electron microscope image (see...). Figure 2 This also indicates that the material has a three-dimensional multi-level porous structure.

[0057] Example 2

[0058] (1) 1.6 g of silicon spheres with a diameter of 100 nm were ultrasonically dispersed in 200 mL of ethanol. Under an argon atmosphere, 4 mL of 3-aminopropyltrimethoxysilane was added and refluxed at 120 °C for 5 h. After reflux, the mixture was cooled to room temperature, centrifuged, washed, and then ultrasonically dispersed together with 150 mg of graphene oxide in 200 mL of ethanol. After stirring at room temperature for 12 h, the mixture was centrifuged and washed to obtain the graphene oxide / silicon sphere composite.

[0059] (2) 150 mg sodium tungstate and graphene oxide / silicon sphere composite were ultrasonically dispersed in 50 mL of deionized water, stirred at room temperature until the solvent was completely evaporated, transferred to an oven and dried at 80 °C for 8 h to obtain a precursor mixture;

[0060] (3) The precursor mixture and 10 mL of CS2 were sealed in a high-temperature reactor under an argon atmosphere;

[0061] (4) Transfer the high-temperature reactor to a muffle furnace and heat it to 400°C at a heating rate of 10°C / min and keep it at that temperature for 4 hours.

[0062] (5) Treat the sample obtained in step (4) with 6 mol / L sodium hydroxide solution for 3 h at a temperature of 60 °C. After treatment, filter the sample and wash it with water and ethanol several times until the filtrate is neutral. Then place it in a drying oven at 80 °C for 12 h.

[0063] (6) The sample obtained in step (5) was treated with a 10% hydrofluoric acid solution for 12 hours. After treatment, the sample was filtered and washed repeatedly with water and ethanol until the filtrate was neutral. The washed sample was placed in a forced-air drying oven and dried at 80°C for 12 hours to obtain the tungsten disulfide / graphene composite material.

[0064] Comparative Example 1

[0065] (1) Dissolve 1.6g of silicon spheres with a diameter of 100nm and 300mg of sodium tungstate in 50mL of deionized water by ultrasonic dispersion. Stir at room temperature until the solvent evaporates completely, then transfer to an oven and dry at 80℃ for 8h.

[0066] (2) The sample in (1) was sealed in a high-temperature reactor under an argon atmosphere and the high-temperature reactor was transferred to a muffle furnace. The temperature was increased to 400℃ at a heating rate of 10℃ / min and held at the temperature for 4h.

[0067] (3) Treat the sample obtained in (2) with 6 mol / L sodium hydroxide solution for 3 h at a temperature of 60 °C. After treatment, filter the sample and wash it with water and ethanol several times until the filtrate is neutral.

[0068] (4) The sample obtained in (3) was treated with a 10% hydrofluoric acid solution for 12 hours. After the treatment, it was filtered and washed with water and ethanol several times until the filtrate was neutral. Then it was placed in a drying oven and dried at 80°C for 12 hours.

[0069] (5) Place the washed sample from (4) in a forced-air drying oven and dry it at 80°C for 12 hours to obtain tungsten disulfide material.

[0070] N2 adsorption-desorption experiment (see...) Figure 1This indicates that the material also has a pore size distribution with varying dimensions. High-resolution scanning electron microscopy image (see...) Figure 3 This indicates that the material also has a three-dimensional multi-level porous structure, but because no graphene was introduced, the structure is more regular.

[0071] Comparative Example 2

[0072] (1) 1.6 g of silicon spheres with a diameter of 100 nm were ultrasonically dispersed in 200 mL of ethanol. Under an argon atmosphere, 4 mL of 3-aminopropyltrimethoxysilane was added and refluxed at 120 °C for 5 h. After reflux, the mixture was cooled to room temperature, centrifuged, washed, and then ultrasonically dispersed together with 150 mg of graphene oxide in 200 mL of ethanol. After stirring at room temperature for 12 h, the mixture was centrifuged, washed, and then transferred to an oven to dry at 80 °C for 8 h.

[0073] (2) Seal the sample and 10 mL CS2 in step (1) in a high-temperature reactor under an argon atmosphere and transfer the high-temperature reactor to a muffle furnace. Proceed to 400°C at a heating rate of 10°C / min and hold at that temperature for 4 hours.

[0074] (3) Treat the sample obtained in step (2) with 6 mol / L sodium hydroxide solution for 3 h at a temperature of 60 °C. After treatment, filter the sample and wash it with water and ethanol several times until the filtrate is neutral.

[0075] (4) The sample obtained in step (3) was treated with a 10% hydrofluoric acid solution for 12 hours. After treatment, the sample was filtered and washed with water and ethanol several times until the filtrate was neutral. Then the sample was placed in a drying oven at 80°C for 12 hours.

[0076] (5) Place the washed sample from step (4) in a forced-air drying oven and dry it at 80°C for 12 hours to obtain graphene material.

[0077] High-resolution scanning electron microscope image (see) Figure 4 This indicates that the material has no obvious porous structure.

[0078] Application Example 1

[0079] The tungsten disulfide / graphene composite material obtained in Example 1 was used in a sodium-ion battery system to investigate its electrochemical performance as a negative electrode material.

[0080] 1. Battery preparation:

[0081] Active material, acetylene black, and binder (PVDF) were weighed in sequence at a mass ratio of 7:2:1 and mixed with an appropriate amount of 1-methyl-2-pyrrolidone to form a uniform active material slurry. The active material slurry was coated onto copper foil using a coating machine and then placed in an oven to dry at 60°C for 24 hours. In an argon-filled glove box (ensuring that the water and oxygen values ​​were both below 0.1 ppm), sodium metal was used as the counter electrode, Whatman glass fiber was used as the separator, and 1.0 M NaPF6 was dissolved in ethylene carbonate with 5 wt% added, ethylene carbonate and dimethyl carbonate in a volume ratio of 1:1 and used as the electrolyte to assemble a CR2032 battery.

[0082] 2. Electrochemical performance evaluation:

[0083] Test conditions:

[0084] Temperature: 30℃; Voltage range: 0.01-3V; Current density: 100mA·g -1 and 2000mA g -1 .

[0085] 3. Discussion of Results:

[0086] At 100mA g -1 At a current density of [value missing], the first charge-discharge capacity of this tungsten disulfide / graphene composite material is 1214 mAh·g. -1 and 469mAh·g -1 Furthermore, after 100 charge-discharge cycles, the material still maintained a capacity of 419 mAh·g. -1 Reversible specific capacity (see) Figure 5 ). At 2000mA g -1 At a current density of up to 1000 charge-discharge cycles, the battery still retains a capacity of up to 244mAh g. -1 Specific capacity (see) Figure 6 ).

[0087] Application Example 2

[0088] The tungsten disulfide / graphene composite material obtained in Example 2 was used in a sodium-ion battery system to investigate its electrochemical performance as a negative electrode material.

[0089] 1. Battery preparation:

[0090] Active material, acetylene black, and binder (PVDF) were weighed in sequence at a mass ratio of 7:2:1 and mixed with an appropriate amount of 1-methyl-2-pyrrolidone to form a uniform active material slurry. The active material slurry was coated onto copper foil using a coating machine and then placed in an oven to dry at 60°C for 24 hours. In an argon-filled glove box (ensuring that the water and oxygen values ​​were both below 0.1 ppm), sodium metal was used as the counter electrode, Whatman glass fiber was used as the separator, and 1.0 M NaPF6 was dissolved in ethylene carbonate with 5 wt% added, ethylene carbonate and dimethyl carbonate in a volume ratio of 1:1 and used as the electrolyte to assemble a CR2032 battery.

[0091] 2. Electrochemical performance evaluation:

[0092] Test conditions:

[0093] Temperature: 30℃; Voltage range: 0.01-3V; Current density: 100mA·g -1 and 2000mA·g -1 .

[0094] 3. Discussion of Results:

[0095] This tungsten disulfide / graphene composite material was tested at a high current of 2000 mA·g. -1 It maintained a capacity of 152 mAh·g after 1000 charge-discharge cycles in cyclic testing. -1 Reversible specific capacity (see) Figure 7 Compared to the material performance data in Application Example 1 (244 mAh g), -1 The current density is relatively low, at 100 mA g -1 The material yielded 318 mAh·g after 100 charge-discharge cycles. -1 Specific capacity ( Figure 8 This is also lower than the 419 mAh·g in Application Example 1. -1 The reversible specific capacity. This comparative result shows that reducing the proportion of tungstate in the raw materials can, to some extent, reduce the battery performance of the material.

[0096] Application Example 3

[0097] The tungsten disulfide material obtained in Comparative Example 1 was used in a sodium-ion battery system to investigate its electrochemical performance as a negative electrode material.

[0098] 1. Battery preparation:

[0099] Active material, acetylene black, and binder (PVDF) were weighed in sequence at a mass ratio of 7:2:1 and mixed with an appropriate amount of 1-methyl-2-pyrrolidone to form a uniform active material slurry. The active material slurry was coated onto copper foil using a coating machine and then placed in an oven to dry at 60°C for 24 hours. In an argon-filled glove box (ensuring that the water and oxygen values ​​were both below 0.1 ppm), sodium metal was used as the counter electrode, Whatman glass fiber was used as the separator, and 1.0 M NaPF6 was dissolved in ethylene carbonate with 5 wt% added, ethylene carbonate and dimethyl carbonate in a volume ratio of 1:1 and used as the electrolyte to assemble a CR2032 battery.

[0100] 2. Electrochemical performance evaluation:

[0101] Test conditions:

[0102] Temperature: 30℃; Voltage range: 0.01-3V; Current density: 100mA·g -1 .

[0103] 3. Discussion of Results:

[0104] The tungsten disulfide material is used at a current density of 100 mA g -1 It exhibited very poor cycle stability under testing, and its specific capacity after 100 charge-discharge cycles was 41 mAh·g. -1 ( Figure 9 The performance of the tungsten disulfide-graphene composite material was far lower than that of the composite material in Application Example 1 and Application Example 2, which shows that the excellent composite of tungsten disulfide and graphene can improve the performance of the material.

[0105] Application Example 4

[0106] The graphene material obtained in Comparative Example 2 was used in a sodium-ion battery system to investigate its electrochemical performance as a negative electrode material.

[0107] 1. Battery preparation:

[0108] Active material, acetylene black, and binder (PVDF) were weighed in sequence at a mass ratio of 7:2:1 and mixed with an appropriate amount of 1-methyl-2-pyrrolidone to form a uniform active material slurry. The active material slurry was coated onto copper foil using a coating machine and then placed in an oven to dry at 60°C for 24 hours. In an argon-filled glove box (ensuring that the water and oxygen values ​​were both below 0.1 ppm), sodium metal was used as the counter electrode, Whatman glass fiber was used as the separator, and 1.0 M NaPF6 was dissolved in ethylene carbonate with 5 wt% added, ethylene carbonate and dimethyl carbonate in a volume ratio of 1:1 and used as the electrolyte to assemble a CR2032 battery.

[0109] 2. Electrochemical performance evaluation:

[0110] Test conditions:

[0111] Temperature: 30℃; Voltage range: 0.01-3V; Current density: 100mA·g -1 .

[0112] 3. Discussion of Results:

[0113] This graphene material is used at a current density of 100 mA g. -1 The specific capacity after 100 charge-discharge cycles was 176 mAh·g. -1 ( Figure 10 Its overall performance, along with that of Application Example 3, is significantly lower than that of Application Example 1 (419 mAh·g). -1 The reversible specific capacity and application example 2: 318 mAh·g -1 The reversible specific capacity. Based on the above results, it can be seen that the excellent performance exhibited by the composite of tungsten disulfide and graphene is far superior to the performance of tungsten disulfide or graphene alone.

[0114] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a tungsten disulfide / graphene composite material, characterized by, The method comprises the following steps: (1) surface modification of a silicon ball ethanol dispersion solution by using 3-aminopropyltrimethoxysilane under the protection of an inert atmosphere by constant temperature reflux to obtain a surface functional group modified silicon ball, and ultrasonic dispersion of the surface functional group modified silicon ball and graphene oxide in an ethanol solution to obtain a graphene oxide / silicon ball composite; (2) deposition of a tungsten salt on the graphene oxide / silicon ball composite obtained in step (1) by using a coprecipitation method to obtain a precursor mixture; (3) transfer of the precursor mixture obtained in step (2) and a sulfur source to a high-temperature reaction kettle under an inert atmosphere two; (4) placing the high-temperature reaction kettle in step (3) in a muffle furnace, and adopting programmed temperature rising to a terminal temperature of 300-600 DEG C and then constant temperature; (5) alkali treatment, washing and drying of the product obtained in step (4) to obtain a silicon ball / tungsten disulfide / graphene composite material; (6) acid treatment, washing and drying of the product obtained in step (5) to obtain a tungsten disulfide / graphene composite material; The tungsten disulfide / graphene composite material has a three-dimensional multi-level porous structure.

2. The production method according to claim 1, characterized by: In step (1), the diameter of the silicon ball in the silicon ball ethanol dispersion solution is 20-400 nm; the inert atmosphere one is one or a mixture of several of argon, nitrogen and helium; the reflux temperature is 50-200 DEG C; and the stirring time is 1-48 h.

3. The method of claim 1, wherein: In step (2), the tungsten salt is any one of ammonium tungstate, ammonium metatungstate, ammonium tetrathiotungstate, sodium metatungstate or sodium tungstate; the coprecipitation temperature is 25-100 DEG C, and the time is 6-72 h.

4. The method of claim 1, wherein: In step (3), the inert atmosphere two is one or a mixture of several of argon, nitrogen and helium; the sulfur source is any one of carbon disulfide, sodium sulfide, potassium sulfide, ammonium sulfide and thioacetamide; and the mass ratio of the tungsten salt to the sulfur source is 1:0.5-2.

5. The method of claim 1, wherein: In step (4), the programmed temperature rising treatment is temperature rising at a temperature rising rate of 1-20 DEG C / min to the terminal temperature, and the constant temperature time is 2-6 h.

6. The method of claim 1, wherein: In step (5), the alkali in the alkali treatment is a sodium hydroxide solution with a concentration of 1-8 mol / L or a potassium hydroxide solution with a concentration of 1-8 mol / L, the alkali treatment time is 2-6 h, the alkali treatment temperature is 60-100 DEG C; the drying temperature is 25-80 DEG C, and the drying time is 4-48 h.

7. The method of claim 1, wherein: In step (6), the acid in the acid treatment is a hydrofluoric acid solution with a mass fraction of 5-20%, the acid treatment time is 4-48 h; the drying temperature is 25-80 DEG C, and the drying time is 4-48 h.

8. Use of a tungsten disulfide / graphene composite material prepared according to the preparation method of any one of claims 1 to 7, characterized in that, The composite material is used as a negative electrode material in a sodium ion battery system.

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