CN110526296A - A kind of preparation method of the tungsten disulfide composite film electrode of doped carbon nanometer pipe - Google Patents

Abstract

The present invention relates to a kind of preparation methods of the tungsten disulfide composite film electrode of doped carbon nanometer pipe, include: that single layer tungsten disulfide nano slices and modified carbon nano-tube are dispersed in deionized water, obtains the tungsten disulfide composite film electrode of doped carbon nanometer pipe by filtering, being freeze-dried.The features such as present invention has method simple, easy to operate, can carry out industrialized production in batches, the film have good chemical property, are mainly used in the fields such as flexible super capacitor, wearable electronic.

Description

A kind of preparation method of tungsten disulfide composite thin film electrode doped with carbon nanotubes

technical field

The invention belongs to the field of preparation of composite thin film electrode materials, in particular to a preparation method of a carbon nanotube-doped tungsten disulfide composite thin film electrode.

Background technique

Two-dimensional transition metal sulfides, as one of the common graphene-like materials, have attracted extensive research because their layered structure makes up for the shortcomings of graphene without a bandgap and easy stacking, which makes the specific surface area ineffective. Tungsten disulfide, molybdenum disulfide and vitriol disulfide are representatives of such materials. Among them, the atoms in the tungsten disulfide nanosheets are combined together by strong covalent bonds, the van der force makes the nanosheets superimposed, and due to its low effective mass, the theoretical mobility of ions should be the highest, so it has good electrochemical performance.

It has been found that the structure of single-layer tungsten disulfide nanosheets is the most similar to the two-dimensional nanosheets of graphene, and both can be used as electrode materials or in catalysis. However, its preparation still remains in chemical vapor deposition and other methods that require high equipment, are difficult to operate and cannot be mass-produced, and the nanosheets are small and difficult to form films, which limit their application in electrochemistry. The invention obtains single-layer tungsten disulfide nanosheets through a liquid phase exfoliation method, and combines carbon nanotubes with tungsten disulfide nanosheets, which conforms to the nanostructure in the electrochemical electrode reaction and has a larger specific surface area, thereby accelerating the electronic The high transmission efficiency and ion intercalation and deintercalation, more active sites and ion transport channels make the composite thin film electrode have more superior electrochemical performance.

CN105870417 discloses a method for preparing a sodium-ion battery disulfide/carbon nanotube negative electrode composite material. The preparation process of the composite material in this method has strict requirements on experimental conditions, especially temperature conditions, and cannot be continuously prepared at room temperature, and the steps are cumbersome. This makes the preparation process of composite materials difficult to leave the laboratory, and it is difficult to achieve continuous and large-scale preparation.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is to provide a preparation method of a carbon nanotube-doped tungsten disulfide composite thin film electrode, which overcomes the cumbersome preparation process, harsh reaction conditions and inability of the tungsten disulfide/carbon nanotube composite material in the prior art. For problems such as preparation at room temperature, firstly, single-layer tungsten disulfide nanosheets were prepared by liquid phase exfoliation method, and then the single-layer tungsten disulfide nanosheets and modified carbon nanotubes were uniformly dispersed in deionized water. The tungsten disulfide composite thin film electrode doped with carbon nanotubes is obtained by freeze-drying.

A preparation method of a carbon nanotube-doped tungsten disulfide composite film of the present invention includes:

(1) dispersing carbon nanotubes in water, adding a surfactant, and ultrasonically treating to obtain a carbon nanotube dispersion;

(2) Mixing the single-layer tungsten disulfide dispersion liquid and the carbon nanotube dispersion liquid, ultrasonically treating, to obtain the mixed dispersion liquid, then suction filtration and freeze-drying to obtain the carbon nanotube-doped tungsten disulfide composite film.

The preferred mode of above-mentioned preparation method is as follows:

In the step (1), the carbon nanotubes are multi-walled carbon nanotubes and/or single-walled carbon nanotubes; the surfactant is sodium dodecylbenzenesulfonate.

In the step (1), the mass ratio of carbon nanotubes to surfactant is 1:3.

The ultrasonic treatment in the step (1) is ultrasonic treatment with a cell crusher, and the time is 60-120 minutes.

In the step (2), the tungsten disulfide dispersion is specifically as follows: using bulk tungsten disulfide as a raw material, preparing monolayer tungsten disulfide nanosheets by a liquid phase exfoliation method, and dispersing the prepared monolayer tungsten disulfide nanosheets in In deionized water, ultrasonic treatment is performed to obtain tungsten disulfide dispersions of different concentrations; wherein the ultrasonic dispersion time is 30-60 minutes.

In the step (2), the single-layer tungsten disulfide is prepared by the liquid phase exfoliation method, specifically: dispersing the tungsten disulfide powder in the n-hexane solution of n-butyllithium, and then stirring under the protection of argon for 3-7 day, lithium ion intercalation is carried out, after the reaction is completed, n-hexane solution is added for dilution, and the residual organolithium compound is removed by centrifugal washing for 3 to 5 times to initially obtain lithium ion intercalated tungsten disulfide nanosheets. After being dispersed in deionized water for 1 to 2 hours, dialysis was performed for 12 to 24 hours for purification, and the purified suspension was centrifuged again for 10 to 15 minutes to remove the unstripped tungsten disulfide to obtain a stripped monolayer of disulfide. Tungsten nanosheets.

The peeling temperature is 20 to 60°C.

In the step (2), the volume ratio of the monolayer tungsten disulfide dispersion to the carbon nanotube dispersion is 5:1 to 1:1; the concentration of the monolayer tungsten disulfide dispersion is 0.5mg/mL to 5mg/mL and the concentration of the carbon nanotube dispersion liquid is 0.2 mg/mL to 5 mg/mL.

In the step (2), the mass ratio of tungsten disulfide to carbon nanotubes is 5-1:1.

In the step (2), the ultrasonic treatment time is 3-10 minutes.

The suction filtration in the step (2) is as follows: suction filtration is performed on a water-based filter membrane, and the pore size of the water-based filter membrane is 0.1 μm to 1 μm;

The freeze-drying temperature is -5～-60℃, and the freeze-drying time is 1～10h.

The invention provides a carbon nanotube-doped tungsten disulfide composite film prepared by the method.

The invention provides an electrode material based on the carbon nanotube-doped tungsten disulfide composite thin film.

A flexible supercapacitor of the present invention includes the carbon nanotube-doped tungsten disulfide composite film.

The application of the carbon nanotube-doped tungsten disulfide composite film of the present invention can be applied to the fields of energy storage devices such as supercapacitors, wearable electronics and the like.

beneficial effect

(1) the present invention adopts the liquid phase exfoliation method to prepare single-layer tungsten disulfide nanosheets, the method is simple and easy to implement and the process is gentle, and it can be prepared at room temperature without adopting the reaction steps such as high temperature calcination and hydrothermal in the existing method;

(2) The carbon nanotube-doped tungsten disulfide composite thin film electrode prepared by the present invention has good electrochemical performance, and the shape and size can be adjusted as needed by changing the size of the suction filtration device or cutting and other methods, and the volume and thickness can be adjusted as needed. It can be regulated by adjusting the concentration and volume of the dispersion, which makes it have great application prospects in the field of flexible electronics and energy storage;

(3) The present invention realizes the controllable morphology of the composite film by changing the doping amount of carbon nanotubes or the type of carbon nanotubes (see Example 2 (Fig. 4) and Example 3 (Fig. 5) respectively by changing the carbon nanotubes. The microstructure of the film is changed according to the doping amount of the tube and the type of carbon nanotubes), and the preparation of composite films with different thicknesses is realized by controlling the volume of the dispersion;

(4) the tungsten disulfide composite thin film electrode doped with carbon nanotubes in the present invention has good electrochemical performance;

(5) The present invention increases the specific surface area and active site of the composite nanostructure through the introduction of carbon nanotubes, increases the ion transport channel, accelerates the insertion and extraction of ions, and improves the electrochemical performance of the electrode;

(6) The introduction of carbon nanotubes in the present invention can expand the interlayer spacing of single-layer tungsten disulfide nanosheets, prevent stacking, and improve electrochemical performance. The composite film has good mechanical properties and can be used as an electrode material for flexible supercapacitors.

Description of drawings

1 is a transmission electron microscope photograph of the tungsten disulfide powder before peeling and the tungsten disulfide nanosheet after peeling in Example 1.

2 is a digital photo of the carbon nanotube-doped tungsten disulfide composite film prepared in Example 1, wherein the inset is a digital photo of the composite film in a bent state.

FIG. 3 is a scanning electron microscope photograph of the carbon nanotube-doped tungsten disulfide composite film prepared in Example 1. FIG.

FIG. 4 is a scanning electron microscope photograph of the carbon nanotube-doped tungsten disulfide composite film prepared in Example 2. FIG.

FIG. 5 is a scanning electron microscope photograph of the carbon nanotube-doped tungsten disulfide composite film prepared in Example 3. FIG.

6 is the cyclic voltammetry curves of the carbon nanotube-doped tungsten disulfide composite films prepared in Examples 1-3 and their corresponding area specific capacitances.

Detailed ways

The present invention will be further described below in conjunction with specific embodiments. It should be understood that these examples are only used to illustrate the present invention and not to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of the present application.

Multi-walled carbon nanotubes (>95%, inner diameter: 3-5 nm, outer diameter: 8-15 nm, length: ~50 μm), single-walled carbon nanotubes (95% (outer diameter: <2 nm, length: ~50 μm) used in the examples : 5-30 μm)) and tungsten disulfide (99.9% metals basis, 2 μm) powders are commercially available.

Example 1

(1) Preparation of monolayer tungsten disulfide nanosheets by liquid phase exfoliation method: monolayer tungsten disulfide nanosheets were prepared by liquid phase exfoliation method. At room temperature, 500 mg of tungsten disulfide powder was dispersed in 5 ml of n-butyllithium in n-hexane solution, and then slowly stirred for 7 days under argon protection to carry out the intercalation reaction. After the reaction was completed, n-hexane was added for dilution and washing, and the dispersion was centrifuged at 8000 rpm for 10 minutes, and repeated 5 times until the residual organolithium compound was removed to obtain Li _x WS ₂ . The Li _x WS ₂ was dispersed in deionized water for 2 h after sonication and dialysis for 24 h for purification. Finally, the purified suspension was centrifuged at 8000 rpm for 15 minutes to remove unpeeled tungsten disulfide, and a single-layer tungsten disulfide nanosheet was obtained. As shown in Figure 1, comparing the exfoliated tungsten disulfide nanosheets with the commercially available tungsten disulfide powder before exfoliation, it is found that the exfoliated disulfide nanosheets are significantly thinner.

(2) Disperse 50 mg of multi-walled carbon nanotubes in 100 mL of deionized water, slowly add 150 mg of sodium dodecyl benzene sulfonate as a surfactant while stirring, and perform ultrasonic treatment with a cell pulverizer for 2 hours to prepare a uniform dispersion. The carbon nanotube dispersion liquid, the concentration is 0.5mg/mL.

(3) Disperse 100 mg of peeled single-layer tungsten disulfide nanosheets in 100 mL of deionized water at room temperature, and ultrasonically treat it for 30 minutes at room temperature to obtain a tungsten disulfide dispersion with a concentration of 1 mg/mL; take 40 mL of 0.5 mg/mL tungsten disulfide dispersion mL of carbon nanotube dispersion was diluted to 100 mL by adding 60 mL of deionized water to obtain 0.2 mg/mL carbon nanotube dispersion. The two solutions were mixed, and ultrasonically treated for 10 minutes to obtain a mixed dispersion with a volume of 200 mL, wherein the mass ratio of tungsten disulfide to carbon nanotubes was 5:1.

(4) Perform suction filtration on the dispersed mixed dispersion of tungsten disulfide and carbon nanotubes with a water-based filter membrane with a pore size of 0.22 μm, stop the suction filtration in time when the water is just drained, and initially obtain the carbon nanotube-doped two Tungsten sulfide composite film. Put it in the refrigerator for 2 hours, transfer it to a freeze dryer, and dry it in a vacuum at -50 °C for 10 hours to obtain a carbon nanotube-doped tungsten disulfide composite film, which is pulled by an electronic universal material testing machine. In the fracture test, when the tensile speed is 20 mm/min, the composite film breaks at the tensile displacement of 0.89 mm, and the corresponding tensile stress at this time is 34.3 MPa, indicating that it has good mechanical properties.

As shown in FIG. 2 , the diameter of the carbon nanotube-doped tungsten disulfide composite film prepared in this example is about 4 cm, and has good bendability.

The scanning electron microscope photo of the carbon nanotube-doped tungsten disulfide composite film prepared in this example is shown in Figure 3. It can be seen that the tungsten disulfide nanosheets are connected to each other through carbon nanotubes, and some holes are formed structure.

As shown in Figure 6, the outermost curve is the cyclic voltammetry curve of the composite thin film electrode when the mass ratio of tungsten disulfide and multi-walled carbon nanotubes is 5:1 in this example, and when the scan rate is 100mV/s , its area specific capacitance is 9.56mF/cm ² .

Example 2

Referring to Example 1, step (3) was changed to take 50 mg of peeled single-layer tungsten disulfide nanosheets and disperse them in 100 mL of deionized water at room temperature, and ultrasonically treated for 30 minutes at room temperature to obtain disulfide with a concentration of 0.5 mg/mL. The tungsten dispersion was mixed with 100 mL of 0.5 mg/mL multi-walled carbon nanotube dispersion, and ultrasonically treated for 10 minutes to obtain a mixed dispersion with a volume of 200 mL of tungsten disulfide and carbon nanotubes with a mass ratio of 1:1. . The rest are the same as in Example 1, and the tungsten disulfide composite film doped with carbon nanotubes is obtained, which is subjected to a tensile test with an electronic universal material testing machine. When the tensile speed is 20mm/min, the composite film has a tensile displacement of The fracture occurs at 0.51mm, and the corresponding tensile stress at this time is 13.1MPa.

As shown in Figure 4, the microstructure of the composite films also changed significantly with the change of the doping amount of carbon nanotubes.

As shown in Fig. 6, the middle curve in this example, when the mass ratio of tungsten disulfide and multi-walled carbon nanotubes is 1:1, the cyclic voltammetry curve of the composite thin film electrode when the scan rate is 100mV/s, its area The specific capacitance was 10.99 mF/cm ² .

Example 3

With reference to Example 1, in step (2), the multi-walled carbon nanotubes are changed to single-walled carbon nanotubes, and the rest are the same as in Example 1, and the tungsten disulfide composite film doped with single-walled carbon nanotubes is obtained. The material testing machine is used for tensile breaking test. When the tensile speed is 20 mm/min, the composite film breaks at a tensile displacement of 0.59 mm, and the corresponding tensile stress at this time is 12.4 MPa.

As shown in Figure 5, from the scanning electron microscope photo of the tungsten disulfide composite film doped with single-walled carbon nanotubes in this example, it can be seen that compared with the composite film doped with multi-walled carbon nanotubes, the doped single-walled carbon nanotubes In the composite film of the tube, the carbon nanotubes are tightly wrapped on the surface of the tungsten disulfide nanosheets, and no pore structure is formed.

As shown in Figure 6, the innermost curve is the cyclic voltammetry curve of the composite thin film electrode when the mass ratio of tungsten disulfide and single-walled carbon nanotubes is 5:1 in this example, and when the scan rate is 100mV/s , its area specific capacitance is 14.65mF/cm ² .

Comparative ratio

The tungsten source and the carbon nanotubes are respectively placed in the upwind area and the downwind area of the dual-temperature zone tube furnace for heating to obtain a tungsten oxide/carbon nanotube composite material precursor, wherein the temperature in the upwind area is 800-1000° C., and the downwind area is 800-1000°C. Temperature 50 ~ 150 ℃. After fully stirring and dispersing the precursor, sulfur powder and reducing agent, the hydrothermal reaction is carried out, and the hydrothermal temperature is 180-250°C. The product obtained by the hydrothermal reaction is filtered, washed, dried and then calcined to obtain a tungsten disulfide/carbon nanotube negative electrode composite material with tungsten disulfide nanosheets uniformly coated on carbon nanotubes. The calcination temperature is 250-350°C. When the magnification is 2000mA/g, the capacity is 200mA h/g, and when the magnification is 100mA/g, the capacity is 305mA h/g. This comparative example is mainly applied to the field of sodium ion batteries, while the present invention is mainly applied to the field of flexible supercapacitors, and the performance parameters of sodium ion batteries and supercapacitors are different.

Claims (10)

1. a kind of preparation method of the tungsten disulfide laminated film of doped carbon nanometer pipe, comprising:

(1) carbon nanotube is dispersed in water, surfactant is added, ultrasonic treatment obtains carbon nano tube dispersion liquid；

(2) tungsten disulfide dispersion liquid and carbon nano tube dispersion liquid being mixed, ultrasonic treatment obtains mixed dispersion liquid, then filter, It is freeze-dried the tungsten disulfide laminated film to get doped carbon nanometer pipe.

2. preparation method according to claim 1, which is characterized in that carbon nanotube is multi-wall carbon nano-tube in the step (1) Pipe and/or single-walled carbon nanotube；Surfactant is neopelex.

3. preparation method according to claim 1, which is characterized in that carbon nanotube and surfactant in the step (1) Mass ratio be 1:3.

4. preparation method according to claim 1, which is characterized in that single layer tungsten disulfide is shelled by liquid phase in the step (2) It is prepared from method, specifically: it disperses tungsten disulfide powder in the hexane solution of n-BuLi, then stirs under protection of argon gas It mixes 3~7 days, carries out lithium ion intercalation, after the reaction was completed, hexane solution is added and is diluted, by centrifuge washing until removing Remaining organo-lithium compound is removed, the tungsten disulfide nano slices of lithium ion intercalation are tentatively obtained, nanometer sheet is dispersed in deionization Ultrasound, dialysis are purified in water, suspension after purification are centrifuged again, the single layer tungsten disulfide for obtaining having removed is received Rice piece.

5. preparation method according to claim 1, which is characterized in that tungsten disulfide dispersion liquid and carbon are received in the step (2) The volume ratio of mitron dispersion liquid is 5:1~1:1；The concentration of single layer tungsten disulfide dispersion liquid is 0.5mg/mL~5mg/mL, carbon is received The concentration of mitron dispersion liquid is 0.2mg/mL~5mg/mL.

6. preparation method according to claim 1, which is characterized in that sonication treatment time is 3~10 points in the step (2) Clock；It filters are as follows: water system filter membrane is filtered, and the pore size of water system filter membrane is 0.1 μm~1 μm；Be freeze-dried temperature be -5~- 60 DEG C, sublimation drying is 1~10h.

7. a kind of tungsten disulfide laminated film of the doped carbon nanometer pipe of claim 1 the method preparation.

8. a kind of electrode material of the tungsten disulfide laminated film based on doped carbon nanometer pipe described in claim 7.

9. a kind of flexible super capacitor, which is characterized in that the tungsten disulfide including doped carbon nanometer pipe described in claim 7 is multiple Close film.

10. a kind of application of the tungsten disulfide laminated film of doped carbon nanometer pipe described in claim 7.