Mesoporous hollow carbon nanospheres in-situ grown tungsten trioxide nanoneedle cluster composite material and its preparation and application

Abstract

The present invention discloses a composite material of mesoporous hollow carbon nanospheres in-situ growing tungsten trioxide nanoneedle clusters, a preparation method thereof, and an application in preparing an anode of a lithium-ion battery. In the composite material of mesoporous hollow carbon nanospheres in-situ growing tungsten trioxide nanoneedle clusters, WO3 nanoneedles aggregate together to form a loose cluster structure, constituting WO3 nanoneedle clusters; the WO3 nanoneedle clusters grow inside the cavity of the mesoporous hollow carbon nanospheres; mesoporous channels that make the shell permeable but can prevent the leakage of WO3 are distributed inside the shell of the mesoporous hollow carbon nanospheres. Preparation method: Sodium tungstate and cobalt nitrate hexahydrate are filled into the mesoporous hollow carbon nanospheres by a solution injection method, and finally sodium tungstate is in-situ transformed into tungsten trioxide through a melting reaction to obtain the composite material of mesoporous hollow carbon nanospheres in-situ growing tungsten trioxide nanoneedle clusters.

Description

Technical Field

[0001] The present invention relates to the technical field of negative electrode materials for lithium ion batteries, and in particular to a method for in-situ growth of tungsten trioxide (WO3) in mesoporous hollow carbon nanospheres. 3 )Nano-needle cluster composite material and its preparation method and application. Background Art

[0002] The rapid development of electric vehicles and large-scale energy storage devices has put forward higher and higher requirements on the performance of lithium-ion batteries. Although graphite has been widely used in lithium-ion battery anodes, the low specific capacity and slow intercalation kinetics of graphite limit the further development of high-performance lithium-ion batteries.

[0003] WO 3 Due to its high mass specific capacity (693 mAh g -1 ) and high volumetric capacity (5274 mAh cm -3 ), environmentally friendly, low cost and high thermal stability, and is considered to be a potential negative electrode material for lithium-ion batteries. 3 The ion transfer kinetics of WO are poor and the inherent conductivity is low, resulting in poor specific capacity and rate performance. 3 The volume change is large, causing the material to pulverize quickly, the structural stability is poor, and the cycle performance is very unsatisfactory. These problems have greatly hindered the development of WO 3 Practical applications in lithium-ion batteries.

[0004] So far, various strategies have been proposed to solve WO 3 Nanostructure engineering and carbon composite are relatively effective methods. The invention patent application with publication number CN112938952A discloses a graphene-coated two-dimensional sheet structure WO 3 Negative electrode material. The invention patent application with publication number CN109616662A discloses a nickel foam loaded WO 3 The invention patent application with publication number CN108598439A discloses WO 3 In general, the current composite structure is difficult to effectively improve the WO 3 Most WO 3 The composite structure with carbon-based materials cannot effectively lock WO 3 Once WO 3 Powdering during cycling still tends to fall off the composite structure, leading to rapid degradation of cycling performance. Summary of the invention

[0005] In view of the above technical problems and the shortcomings in the art, the present invention provides a mesoporous hollow carbon nanosphere in-situ grown tungsten trioxide nanoneedle cluster composite material (also referred to as WO in the present invention) 3 @Mesoporous hollow carbon nanospheres) have the characteristics of simple and mild synthesis process, unique structure and excellent lithium storage performance.

[0006] A mesoporous hollow carbon nanosphere in-situ grown tungsten trioxide nanoneedle cluster composite material, WO 3 The nanoneedles aggregate together to form a loose cluster structure, forming WO 3 Nanoneedle cluster; the WO 3 The nanoneedle cluster grows inside the cavity of the mesoporous hollow carbon nanosphere; the shell of the mesoporous hollow carbon nanosphere is distributed with a material that makes the shell permeable but can prevent WO 3 Leakage of mesopores.

[0007] Preferably, the WO 3 The thickness of the nanoneedles is 1-20 nm and the length is 50-500 nm.

[0008] Preferably, the outer diameter of the mesoporous hollow carbon nanospheres is 100-1000 nm, and the shell thickness is 10-100 nm;

[0009] Preferably, the size of the mesopores is less than 10 nm.

[0010] Preferably, in the mesoporous hollow carbon nanosphere in-situ grown tungsten trioxide nanoneedle cluster composite material, WO 3 The quality percentage is 30%-90%.

[0011] Preferably, the mesoporous hollow carbon nanospheres are amorphous carbon materials formed by decomposing RF resin (phenolic resin).

[0012] The present invention also provides a method for preparing the mesoporous hollow carbon nanosphere in-situ grown tungsten trioxide nanoneedle cluster composite material, comprising the steps of:

[0013] (1) The mesoporous hollow carbon nanospheres are uniformly dispersed in a sodium tungstate aqueous solution, and then allowed to stand, the supernatant is removed, and the solution is centrifuged at a speed of more than 15000 rpm, and the precipitate is dried to obtain Na 2 WO 4 @Mesoporous hollow carbon nanospheres;

[0014] (2) Put Na 2 WO 4 @Mesoporous hollow carbon nanospheres were uniformly dispersed in ethanol, and then Co(NO 3 ) 2 6H 2O, fully stirred and then dried, the dried product was heated to 105-115° C. under vacuum conditions and kept warm for 80-100 minutes, and finally washed and dried to obtain the mesoporous hollow carbon nanosphere in-situ grown tungsten trioxide nanoneedle cluster composite material.

[0015] The present invention uses a method of injecting aqueous solution into Na 2 WO 4 The mesoporous hollow carbon nanospheres were filled and Co(NO 3 ) 2 6H 2 O is filled into the mesoporous hollow carbon nanospheres, and finally Na 2 WO 4 In situ conversion to WO 3 , get WO 3 @Mesoporous hollow carbon nanospheres. The present invention can effectively improve WO 3 The conductivity can effectively lock the powdered WO 3 , enhancing the structural stability and cyclic stability of the composite material.

[0016] The present invention can adopt the template method to synthesize mesoporous hollow carbon nanospheres.

[0017] Preferably, in step (1), the method for preparing mesoporous hollow carbon nanospheres comprises the steps of:

[0018] (a) Add tetrapropoxysilane to an ethanol aqueous solution of ammonia, mix well, add resorcinol and formaldehyde, and after sufficient reaction, wash and dry the resulting precipitate to obtain SiO 2 @RF resin / SiO 2 ;

[0019] (b) SiO 2 @RF resin / SiO 2 Carbonize at 500-800℃ for 1-3h in an inert gas atmosphere to obtain SiO 2 @Carbon / SiO 2 ;

[0020] (c) Etching SiO with hydrofluoric acid 2 @Carbon / SiO 2 Removal of SiO 2 , washing and drying to obtain the mesoporous hollow carbon nanospheres.

[0021] A preferred preparation method of the mesoporous hollow carbon nanosphere in-situ grown tungsten trioxide nanoneedle cluster composite material comprises the following steps:

[0022] 1) Slowly add 3.0 mL of ammonia water (25-28 wt%) to a mixed solution of 70 mL of ethanol and 10 mL of deionized water. After stirring for 15 min in a water bath at 25°C, add 3.46 mL of tetrapropoxysilane and continue stirring for 5-45 min. Then add 0.1-1 g of resorcinol and 0.1-1 mL of formaldehyde aqueous solution (35-40 wt%) respectively, stir for 24 h, and obtain a light yellow precipitate, which is washed with deionized water and dried at 60°C to obtain SiO 2 @RF resin / SiO 2 Put it into a tube furnace and carbonize it in an argon atmosphere at a carbonization temperature of 500-800°C for 1-3h to obtain SiO 2 @Carbon / SiO 2 . Hydrofluoric acid solution (25.0 wt%) was used to etch away SiO 2 , washed with deionized water, and dried at 60 °C to obtain mesoporous hollow carbon nanospheres.

[0023] 2) 1.0-8.0g of Na 2 WO 4 ·2H 2 O was dissolved in 20 mL of deionized water. 0.025 g of mesoporous hollow carbon nanospheres was added and ultrasonically dispersed for 5 min. The solution was allowed to stand for 24 h. The supernatant was extracted with a rubber-tipped dropper and centrifuged at 15,000 rpm or higher. The precipitate was dried at 60 °C to obtain Na 2 WO 4 @Mesoporous hollow carbon nanospheres. 0.025g of Na 2 WO 4 @Mesoporous hollow carbon nanospheres were ultrasonically dispersed in 20 mL of ethanol, and then 0.04-0.32 g Co(NO 3 ) 2 6H 2 O, stirred for 10 min, and dried at 60 ° C. Then put the product into an oven, evacuated, heated to 110 ° C, and kept warm for 90 min. The product was washed with ethanol 3 times, washed with deionized water 3 times, centrifuged, and dried at 60 ° C to obtain WO 3 @Mesoporous hollow carbon nanospheres.

[0024] The mesoporous hollow carbon nanospheres of the present invention can regulate the growth of tungsten trioxide, and the obtained composite structure can significantly improve the specific capacity and cycle stability of tungsten trioxide, and is an excellent negative electrode material for lithium batteries.

[0025] The present invention also provides the use of the mesoporous hollow carbon nanosphere in-situ grown tungsten trioxide nanoneedle cluster composite material in preparing a negative electrode of a lithium ion battery.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] 1. The present invention uses a method of injecting aqueous solution into Na 2 WO 4 Fill the interior of the mesoporous hollow carbon nanospheres; then use Na 2 WO 4 Insoluble in ethanol, Co(NO 3 ) 2 6H 2 O is soluble in ethanol. The Co(NO 3 ) 2 6H 2 O is filled into the mesoporous hollow carbon nanospheres; then heated to above the melting point of cobalt nitrate, the capillary action will move the molten Co(NO 3 ) 2 6H 2 O is further absorbed, and then the molten Co(NO 3 ) 2 6H 2 O makes Na 2 WO 4 Decomposes into tungstic acid, dehydrates into WO 3 In this reaction, the crystal water of cobalt nitrate is the key. Without crystal water, the reaction will not proceed. If the entire material is put into an aqueous solution, both cobalt nitrate and sodium tungstate will dissolve and flow out of the mesoporous hollow carbon nanospheres, resulting in WO 3 The present invention utilizes the crystal water and molten state of cobalt nitrate to react, and the outflow of cobalt nitrate and sodium tungstate will not occur, thus ensuring the WO 3 In situ growth inside mesoporous hollow carbon nanospheres.

[0028] 2. Mesoporous hollow carbon nanospheres can improve the internal WO 3 The mesoporous channels on the shell facilitate the penetration of electrolytes, and the large internal space can store electrolytes, promoting the WO 3 Full contact with the electrolyte. The large internal space allows WO 3 Free expansion and contraction minimizes internal stress. The semi-enclosed space can effectively lock WO 3 Even if it is powdered, it cannot fall off from the carbon nanospheres, ensuring the integrity of the composite material.

[0029] 3. Due to Na 2 WO 4 and Co(NO 3 ) 2 6H 2 O is injected into the mesoporous hollow carbon nanospheres before reacting, and the filling amount is limited, resulting in Na 2 WO4 The decomposition reaction is very mild, and the growth of WO 3 The size is very small and the structure is loose, so it has high electrochemical activity and excellent lithium storage performance. 3 The growth has a unique confinement effect, which is different from the free growth of hollow carbon nanospheres without mesopores. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a transmission electron microscope (TEM) photograph of the mesoporous hollow carbon nanospheres prepared in Example 1;

[0031] Figure 2 The Na prepared in Example 1 2 WO 4 @TEM image of mesoporous hollow carbon nanospheres;

[0032] Figure 3 WO prepared in Example 1 3 @Scanning electron microscope (SEM) image of mesoporous hollow carbon nanospheres;

[0033] Figure 4 WO prepared in Example 1 3 @TEM image of mesoporous hollow carbon nanospheres;

[0034] Figure 5 WO prepared in Example 1 3 @XRD pattern of mesoporous hollow carbon nanospheres;

[0035] Figure 6 WO prepared in Example 1 3 @Mesoporous hollow carbon nanospheres and mesoporous hollow carbon nanospheres, pure WO 3 At a current density of 0.2 A g -1 Cycle performance diagram below;

[0036] Figure 7 Pure WO prepared in comparative example 3 SEM photograph of. DETAILED DESCRIPTION

[0037] The present invention will be further described below in conjunction with the accompanying drawings and specific examples. It should be understood that these examples are only intended to illustrate the present invention and are not intended to limit the scope of the present invention. The operating methods in the following examples without specifying specific conditions are usually carried out under conventional conditions or under conditions recommended by the manufacturer.

[0038] Example 1

[0039] (1) 3.0 mL of ammonia water (25-28 wt%) was slowly added to a mixed solution of 70 mL of ethanol and 10 mL of deionized water. After stirring for 15 min in a water bath at 25°C, 3.46 mL of tetrapropoxysilane was added and the stirring was continued for 15 min. Then 0.4 g of resorcinol and 0.56 mL of formaldehyde aqueous solution (37 wt%) were added respectively and stirred for 24 h to obtain a light yellow precipitate, which was washed with deionized water and dried at 60°C to obtain SiO 2 @RF resin / SiO 2 It was placed in a tube furnace and carbonized under an argon atmosphere at a temperature of 600°C for 2 hours to obtain SiO 2 @Carbon / SiO 2 . Hydrofluoric acid solution (25.0 wt%) was used to etch away SiO 2 , washed with deionized water, and dried at 60 °C to obtain mesoporous hollow carbon nanospheres.

[0040] (2) Add 5.0 g of Na 2 WO 4 ·2H 2 O was dissolved in 20 mL of deionized water. 0.025 g of mesoporous hollow carbon nanospheres was added and ultrasonically dispersed for 5 min. The solution was allowed to stand for 24 h. The supernatant was extracted with a rubber-tipped dropper and centrifuged at 15,000 rpm. The precipitate was dried at 60 °C to obtain Na 2 WO 4 @Mesoporous hollow carbon nanospheres. 0.025g of Na 2 WO 4 @Mesoporous hollow carbon nanospheres were ultrasonically dispersed in 20 mL of ethanol, and then 0.2 g Co(NO 3 ) 2 6H 2 O, stirred for 10 min, and dried at 60 ° C. Then put the product into an oven, evacuated, heated to 110 ° C, and kept warm for 90 min. The product was washed with ethanol 3 times, washed with deionized water 3 times, centrifuged, and dried at 60 ° C to obtain WO 3 @Mesoporous hollow carbon nanospheres.

[0041] Figure 1 This is a TEM photo of mesoporous hollow carbon nanospheres. The outer diameter of the carbon spheres is about 200-250nm, the shell thickness is 30-50nm, and the diameter of the mesopores on the shell is less than 5nm. Figure 2 Yes 2 WO 4 @TEM photo of mesoporous hollow carbon nanospheres. Some nanoparticles appeared inside each carbon sphere, indicating that Na 2 WO 4 Encapsulated inside mesoporous hollow carbon nanospheres, the hollow carbon sphere structure remains intact without damage. Figure 3 It is WO 3 @SEM photo of mesoporous hollow carbon nanospheres. The surface of the spheres is smooth, each sphere is relatively full, and the light transmittance is low, indicating that the reaction has occurred inside. There are no impurities outside the spheres, indicating that the reaction is taking place inside the spheres. Figure 4 This is a TEM photo. The particles inside the carbon sphere have become needle clusters. The thickness of the nanoneedles is 5-10nm and the length is about 100-150nm. The needle clusters are fluffy and not dense, which leads to WO 3 High electrochemical activity. There are also a lot of voids inside the carbon spheres, which provide buffer space and electrolyte storage space. Figure 5 It is WO 3 @XRD spectrum of mesoporous hollow carbon nanospheres. The diffraction peaks at 23.4°, 33.7° and 59.5° are similar to those of WO 3 (200), (220) and (422) planes of WO 3 Successfully synthesized. The diffraction peaks are broadened, indicating that the particle size is small. A broadened hump appears at 15-35°, which is attributed to the amorphous mesoporous hollow carbon nanospheres. In addition to WO 3 The diffraction peaks of 2 WO 4 and Co(NO 3 ) 2 6H 2 The diffraction peaks of impurities such as O indicate that the reaction is complete and the product is of high purity. Thermogravimetric analysis under air shows that the WO in the composite material 3 The quality accounts for 82%.

[0042] Using the WO of this embodiment 3 @Mesoporous hollow carbon nanosphere composite material for lithium-ion battery negative electrode: weigh WO with a mass ratio of 80:10:10 respectively 3 @Mesoporous hollow carbon nanosphere composite material, acetylene black conductive agent, PVDF binder, dissolve PVDF in an appropriate amount of N-methylpyrrolidone, stir until completely dissolved, then add the evenly ground active material and acetylene black to the above solution, continue stirring to ensure that the slurry is evenly mixed. Then evenly coat the slurry on a disc copper foil (diameter 12mm), dry it in a vacuum oven at 100℃, and finally flatten it on a tablet press with a pressure of 10MPa to obtain an electrode sheet.

[0043] The prepared electrode sheet, lithium sheet and diaphragm were assembled into a CR2025 button-type lithium-ion battery in a glove box filled with high-purity argon. The electrolyte was 1 mol / L LiPF 6 EC / DMC electrolyte is used to test the charge and discharge performance and cycle performance of lithium-ion batteries using the Xinwei battery testing system.

[0044] Figure 6 For WO 3 @Mesoporous hollow carbon nanospheres and mesoporous hollow carbon nanospheres, pure WO 3 At a current density of 0.2A -1 Cycle performance diagram under WO 3 @The first discharge capacity of mesoporous hollow carbon nanospheres is 1931 mAh g -1 The discharge capacity in subsequent cycles was relatively stable, with an average value of 1180 mAh g -1 After 50 cycles, the discharge capacity reaches 1094 mAh g -1 In contrast, pure mesoporous hollow carbon nanospheres and pure WO 3 The cycle performance is also stable, but the average discharge capacity is 564 mAh g -1 and 224mAh g -1 , only for WO 3 @48% and 19% of mesoporous hollow carbon nanospheres. After 50 cycles, pure mesoporous hollow carbon nanospheres and pure WO 3 The discharge specific capacities are 593 and 182 mAh g -1 This shows that WO 3 @The high capacity of mesoporous hollow carbon nanospheres mainly comes from WO 3 Mesoporous hollow carbon nanospheres greatly improve WO 3 lithium storage performance.

[0045] WO 3 @The cyclic performance of the mesoporous hollow carbon nanosphere composite material is better than that of a graphene-coated two-dimensional sheet structure WO reported in the invention patent application with publication number CN112938952A 3 At a current density of 0.1A -1 The discharge capacity after 150 cycles is about 1007 mAh g -1 ; Better than a WO reported in the invention patent application with publication number CN108598439A 3 The maximum discharge capacity of the graphene composite material is about 1069 mAh g -1 ; Better than a WO reported in the invention patent application with publication number CN107180951A 3 / WO 2 The composite material was subjected to a current density of 0.1Ag -1 The discharge capacity is about 680 mAh g -1 .

[0046] Example 2

[0047] (1) 3.0 mL of ammonia water (25-28 wt%) was slowly added to a mixed solution of 70 mL of ethanol and 10 mL of deionized water. After stirring for 15 min in a water bath at 25°C, 3.46 mL of tetrapropoxysilane was added and stirring continued for 30 min. Then 0.5 g of resorcinol and 0.7 mL of formaldehyde aqueous solution (37 wt%) were added respectively and stirred for 24 h to obtain a light yellow precipitate, which was washed with deionized water and dried at 60°C to obtain SiO 2 @RF resin / SiO 2 It was placed in a tube furnace and carbonized under an argon atmosphere at a temperature of 600°C for 2 hours to obtain SiO 2 @Carbon / SiO 2 . Hydrofluoric acid solution (25.0 wt%) was used to etch away SiO 2 , washed with deionized water, and dried at 60 °C to obtain mesoporous hollow carbon nanospheres.

[0048] The subsequent steps are the same as those in Example 1.

[0049] Product WO 3 @The structure of the mesoporous hollow carbon nanosphere composite material is similar to that of Example 1, the main difference being that the outer diameter of the mesoporous hollow carbon nanosphere is increased to about 300-350 nm, and the shell thickness is 20-40 nm. 3 The morphology of the composite material remains unchanged and its content in the composite material is 76wt%.

[0050] Example 3

[0051] (1) 3.0 mL of ammonia water (25-28 wt%) was slowly added to a mixed solution of 70 mL of ethanol and 10 mL of deionized water. After stirring for 15 min in a water bath at 25°C, 3.46 mL of tetrapropoxysilane was added and the stirring was continued for 15 min. Then 0.4 g of resorcinol and 0.56 mL of formaldehyde aqueous solution (37 wt%) were added respectively and stirred for 24 h to obtain a light yellow precipitate, which was washed with deionized water and dried at 60°C to obtain SiO 2 @RF resin / SiO 2 It was placed in a tube furnace and carbonized under an argon atmosphere at a temperature of 600°C for 2 hours to obtain SiO 2 @Carbon / SiO 2 . Hydrofluoric acid solution (25.0 wt%) was used to etch away SiO 2 , washed with deionized water, and dried at 60 °C to obtain mesoporous hollow carbon nanospheres.

[0052] (2) 3.0 g of Na 2 WO 4 ·2H 2O was dissolved in 20 mL of deionized water. 0.025 g of mesoporous hollow carbon nanospheres was added and ultrasonically dispersed for 5 min. The solution was allowed to stand for 24 h. The supernatant was extracted with a rubber-tipped dropper and centrifuged at 15,000 rpm. The precipitate was dried at 60 °C to obtain Na 2 WO 4 @Mesoporous hollow carbon nanospheres. 0.025g of Na 2 WO 4 @Mesoporous hollow carbon nanospheres were ultrasonically dispersed in 20 mL of ethanol, and then 0.12 g Co(NO 3 ) 2 6H 2 O, stirred for 10 min, and dried at 60 ° C. Then put the product into an oven, evacuated, heated to 110 ° C, and kept warm for 90 min. The product was washed with ethanol 3 times, washed with deionized water 3 times, centrifuged, and dried at 60 ° C to obtain WO 3 @Mesoporous hollow carbon nanospheres.

[0053] Product WO 3 @The structure of the mesoporous hollow carbon nanosphere composite material is similar to that of Example 1, the main difference is that WO 3 The content in the composite material was reduced to 48 wt%.

[0054] Comparative Example

[0055] 0.1 g Na 2 WO 4 ·2H 2 O was placed in 50 mL of deionized water and stirred until dissolved. 10 mL of HCl solution (concentration 10 wt%) was added to the solution and stirred for 5 min. The mixed solution was then transferred to a 100 mL high pressure sealed reactor, heated to 120 ° C for 2 h, cooled to room temperature, centrifuged to separate the product, washed with water and ethanol several times, and dried at 60 ° C to obtain the product pure WO 3 .

[0056] Figure 7 It is pure WO 3 SEM images of pure WO 3 The material size is increased to micrometer level, and the agglomeration phenomenon is very serious. 3 The small size and fluffy cluster structure are obviously different, proving that the mesoporous hollow carbon nanospheres act as nanoreaction containers and change the WO 3 Growth law. Figure 6 As shown, pure WO 3 The reversible capacity is low and it is not suitable as a negative electrode material for lithium-ion batteries.

[0057] In addition, it should be understood that after reading the above description of the present invention, those skilled in the art may make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the claims attached to this application.

Claims

1. A method for preparing a composite material of in-situ growth of mesoporous hollow carbon nanospheres and tungsten trioxide nanoneedle clusters, It is characterized in that WO 3 The nanoneedles aggregate together to form a loose cluster structure, forming WO 3 Nanoneedle cluster; the WO 3 The nanoneedle cluster grows inside the cavity of the mesoporous hollow carbon nanosphere; the shell of the mesoporous hollow carbon nanosphere is distributed with a material that makes the shell permeable but can prevent WO 3 Leaky mesopores; The preparation method of the mesoporous hollow carbon nanosphere in-situ grown tungsten trioxide nanoneedle cluster composite material comprises the following steps: (1) The mesoporous hollow carbon nanospheres are uniformly dispersed in a sodium tungstate aqueous solution, and then allowed to stand. The supernatant is removed and centrifuged at a speed of more than 15,000 rpm. The precipitate is dried to obtain Na 2 WO 4 @Mesoporous hollow carbon nanospheres; (2) Put Na 2 WO 4 @Mesoporous hollow carbon nanospheres were uniformly dispersed in ethanol, and then Co(NO 3 ) 2 6H 2 O, fully stirred and then dried, the dried product was heated to 105-115° C. under vacuum conditions and kept warm for 80-100 min, and finally washed and dried to obtain the mesoporous hollow carbon nanosphere in-situ grown tungsten trioxide nanoneedle cluster composite material.

2. The method for preparing the composite material of mesoporous hollow carbon nanospheres in-situ grown tungsten trioxide nanoneedle clusters according to claim 1, It is characterized in that The WO 3 The thickness of the nanoneedles is 1-20 nm and the length is 50-500 nm; The outer diameter of the mesoporous hollow carbon nanospheres is 100-1000 nm, and the shell thickness is 10-100 nm; The size of the mesopores is less than 10 nm.

3. The method for preparing the composite material of mesoporous hollow carbon nanospheres in-situ grown tungsten trioxide nanoneedle clusters according to claim 1, It is characterized in that In the mesoporous hollow carbon nanosphere in-situ grown tungsten trioxide nanoneedle cluster composite material, WO 3 The quality percentage is 30%-90%.

4. The method for preparing the composite material of mesoporous hollow carbon nanospheres in-situ grown tungsten trioxide nanoneedle clusters according to claim 1, It is characterized in that The mesoporous hollow carbon nanospheres are amorphous carbon materials formed by decomposing RF resin.

5. The method for preparing the composite material of in-situ growth of mesoporous hollow carbon nanospheres and tungsten trioxide nanoneedle clusters according to claim 1, It is characterized in that In step (1), the method for preparing mesoporous hollow carbon nanospheres comprises the steps of: (a) Add tetrapropoxysilane to an ethanol solution of ammonia water, mix well, add resorcinol and formaldehyde, and after sufficient reaction, wash and dry the resulting precipitate to obtain SiO 2 @RF resin / SiO 2 ; (b) SiO 2 @RF resin / SiO 2 Carbonize at 500-800 °C for 1-3 h in an inert gas atmosphere to obtain SiO 2 @Carbon / SiO 2 ; (c) Etching SiO with hydrofluoric acid 2 @Carbon / SiO 2 Removal of SiO 2 , washing and drying to obtain the mesoporous hollow carbon nanospheres.

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