CN108649190B - Vertical graphene/titanium-niobium-oxygen/sulfur-carbon composite material with three-dimensional porous array structure and its preparation method and application - Google Patents

Abstract

The invention discloses a vertical graphene/titanium niobium oxide/sulfur-carbon composite material with a three-dimensional porous array structure and a preparation method and application thereof, which include: a graphene nanosheet grown vertically and intertwined on a substrate; TiNb ₂ O ₇ on the graphene nanosheets to form VG/TiNb ₂ O ₇ nanosheets; and a sulfur-doped carbon layer coated on the VG/TiNb ₂ O ₇ nanosheets to form VG/TiNb ₂ O ₇ @ S‑C three-dimensional porous array. The present invention reversely synthesizes VG/TiNb ₂ O ₇ nanometer array, which is used as a carrier to prepare the composite material of the present invention through constant current anode deposition. The composite material of the invention has the characteristics of high cycle stability, high rate performance and Coulomb efficiency, and can significantly improve the energy density/power density and cycle stability of the full battery when matched with lithium iron phosphate or ternary materials. The novel composite material of the present invention is suitable as a negative electrode material for a lithium ion battery, and can be applied to various electronic devices, electric vehicles, hybrid vehicles and the like.

Description

Vertical graphene/titanium niobium oxide/sulfur-carbon composites with three-dimensional porous array structure Preparation method and application thereof

technical field

The invention relates to the technical field of negative electrode materials for lithium ion secondary batteries, in particular to a vertical graphene/titanium niobium oxide/sulfur carbon composite material with a three-dimensional porous array structure, a preparation method thereof, and an application as a negative electrode material for lithium ion batteries.

Background technique

Lithium-ion batteries are widely used in transportation, information electronics and other fields as the most important electrical energy storage device. The rapid development of lithium-ion batteries mainly depends on the innovation of positive and negative electrode materials. However, the most widely used negative electrode active graphite material is easy to form dendrites, and silicon and tin-based compounds have serious volume expansion problems. Moreover, it is easy to form SEI film (solid electrolyte interface), which has poor safety. . Although lithium titanate does not form an SEI film, its theoretical capacity is low. Titanium niobate compound (TiNb _x O _2+2.5x ) does not form an SEI film during cycling, and its theoretical capacity is relatively high, which has attracted great attention. . Among the titanium niobate compounds, TiNb ₂ O ₇ and Ti ₂ Nb ₁₀ O ₂₉ are widely used, with theoretical capacities of 388 and 396mAh g ^-1 , respectively. Among them, TiNb ₂ O ₇ was first proposed by Goodenough's research group. In its working voltage range, there is no SEI film formation, and the theoretical capacity is higher, slightly higher than that of graphite. However, the intrinsic electronic/ionic conductivity of titanium niobate materials is low, which limits the high-rate electrochemical performance. Therefore, in order to design the titanium niobate material into a high-performance lithium-ion battery electrode, it must be modified.

In response to the above problems, researchers at home and abroad usually use the following modification methods to optimize its electrochemical lithium storage performance: there are mainly three methods: nanometerization, metal ion doping, and surface coating. The electrode material is designed and synthesized into nanostructures such as nanotubes, nanowires, nanoparticles, etc., which reduces the electron/lithium ion transmission path and accelerates the transmission speed, thereby improving the electron/ion transmission efficiency; using Ru ⁴⁺ , Cu ²⁺ , Mo ⁶⁺ Doping with other metal ions provides more vacancies to facilitate ion transport, thereby improving its high-rate electrochemical performance; using Ag, CNTs (carbon nanotubes), graphene (graphene) and other highly conductive coating layers to improve its electrodes / Electrolyte contact interface, reduce the electrochemical impedance of the interface and improve the electronic conductivity. However, most of the above modifications are based on powder materials. The presence of binders and additives in powder electrodes limits the further improvement of their electrochemical performance. Thin film composites do not require binders/additives and are suitable as an alternative to powdered materials. Therefore, it is very urgent to find a substrate material with high specific surface area and high electrical conductivity, and it is also the first choice for constructing high-performance titanium niobate-based lithium-ion batteries. However, in the array structure, the electrode material TiNb ₂ O ₇ will be in direct contact with the electrolyte, lacking a fast electron transport channel. Efficient surface conductive cladding can provide channels for it and further enhance the electrochemical performance. The VG/TiNb ₂ O ₇ @SC composite porous array electrodes synthesized above have high rate performance, cycling stability and Coulombic efficiency, and are expected to be commercialized high power density and energy density lithium-ion battery anode materials.

SUMMARY OF THE INVENTION

In view of the problems in the background technology, the purpose of the present invention is to synthesize VG/TiNb ₂ O ₇ @SC composite porous array electrodes with high specific surface area, and synergistically optimize the three-dimensional nanoporous array substrate and the surface-coated carbon layer to improve the intrinsic electron / low ion mobility problem.

The invention provides a vertical graphene/titanium niobium oxide/sulfur carbon composite material with a three-dimensional porous array structure, a preparation method thereof, and an application as a negative electrode material for a lithium ion battery, and a VG/TiNb ₂ O ₇ @ The SC composite porous array electrode includes a VG nanoporous array substrate, a TiNb ₂ O ₇ active material, and an SC amorphous surface-coated carbon layer. The VG/TiNb ₂ O ₇ @SC composite porous array electrode was prepared by plasma chemical vapor deposition (PECVD), solvothermal method and galvanostatic anodic deposition. The thickness of the VG/TiNb ₂ O ₇ nanosheet was 20-50 nm, The thickness of the VG/TiNb ₂ O ₇ @SC core-shell array is 50-120 nm.

Vertical graphene/titanium-niobium-oxygen/sulfur-carbon composites with a three-dimensional porous array structure, including:

Vertical and entangled graphene nanosheets (VG) on the substrate to form a three-dimensional nanoporous structure;

The TiNb ₂ O ₇ (ie TNO) coated on the graphene nanosheets forms VG/TiNb _{2 O7} nanosheets;

and the sulfur-doped carbon layer (SC) coated on the VG/TiNb ₂ O ₇ nanosheets to form a VG/TiNb ₂ O ₇ @SC three-dimensional porous array.

The thickness of the graphene nanosheet is 5-8 nm, the thickness of the VG/TiNb ₂ O ₇ nano sheet is 20-50 nm, and the thickness of the VG/TiNb ₂ O ₇ @SC three-dimensional porous array finally obtained (ie VG/TiNb ₂ O ₇ @SC core-shell array nanosheet thickness) is 50-120 nm.

Vertical graphene/titanium niobium oxide/sulfur-carbon composite material with three-dimensional porous array structure, i.e. high energy density/power density composite lithium-ion battery anode material for improving electron/ion conductivity, the material is composed of three-dimensional nanoporous array substrate It is composed and synergistically optimized with the surface-coated carbon layer.

The composite VG/TiNb ₂ O ₇ @SC three-dimensional porous array is composed of a nanoporous array composed of entangled vertical graphene nanosheets (VG ~ 5-8 nm) as a conductive substrate, and solvothermally grown to coat TNO to form (VG/TiNb ₂ O ₇ ) core with an amorphous sulfur-doped carbon layer (SC) with a thickness of 20-50 nm, VG/TiNb ₂ O _{7 @SC} core _- shell array The nanosheet thickness is 50-120 nm.

A method for preparing a vertical graphene/titanium niobium oxide/sulfur-carbon composite material with a three-dimensional porous array structure, comprising the following steps:

(1) Preparation method of vertical graphene (VG): by plasma-enhanced chemical vapor deposition (PECVD), the graphene array is deposited on carbon cloth in an orderly manner to obtain vertical graphene nanosheets (VG);

(2) Preparation method of VG/TiNb ₂ O ₇ : drying the vertical graphene nanosheets, using the vertical graphene nanosheets as a growth substrate, using isopropyl titanate (C ₁₂ H ₂₈ O ₄ Ti) and five Niobium chloride (NbCl ₅ ) is used as a precursor to carry out a solvothermal reaction, and after the reaction is completed, cleaning, drying, heat treatment and calcination are performed to obtain VG/TiNb ₂ O ₇ nanosheets;

(3) Preparation method of VG/TiNb ₂ O ₇ @SC: 3,4-ethylenedioxythiophene (EDOT) and LiClO ₄ were dissolved in acetonitrile, and the prepared VG/TiNb ₂ O was deposited by galvanostatic anodic deposition. After depositing PEDOT (a polymer of EDOT) on the ₇ -nanometer sheet, and calcining, a vertical graphene/titanium-niobium-oxygen/sulfur-carbon composite material with a three-dimensional porous array structure was obtained.

In step (1), in the plasma-enhanced chemical vapor deposition method, the microwave frequency is 2.2-2.6GHz and the microwave power is 1.5kW-2.5kW, and further preferably, the microwave frequency is 2.45GHz and the microwave power is 2kW.

Specifically include:

First, the carbon is placed in the cavity and its gas pressure reaches 10 mTorr;

Secondly, after raising the chamber temperature to 400°C, hydrogen plasma was generated in the chamber, and the hydrogen plasma was generated in the _H2 gas flow with a flow rate of 90sccm by 500W microwave plasma, and methane was introduced at the same time. During the whole reaction process, The volume ratio of hydrogen and methane is 3:2, and the reaction time is kept at 2h;

Finally, it is cooled to obtain graphene nanosheets vertically grown on the carbon cloth, namely vertical graphene nanosheets (VG).

In step (2), the mass ratio of isopropyl titanate (C ₁₂ H ₂₈ O ₄ Ti) to niobium pentachloride (NbCl ₅ ) is 1:1.5-2.5, more preferably, 0.5684g:1.08g .

The reaction conditions of the solvothermal reaction are: 180°C～220°C for 4h～8h, more preferably, 200°C for 6h.

The conditions for the heat treatment and calcination are: 600°C～800°C heat treatment and calcination for 1h～3h, more preferably, 700°C heat treatment and calcination for 2h.

The heat treatment and calcination are carried out in an argon protective atmosphere.

In step (3), the ratio of 3,4-ethylenedioxythiophene (EDOT), LiClO ₄ and acetonitrile is 0.3mL-0.7mL: 0.5g-1.5g: 80mL-120mL, more preferably 0.5 mL: 1g: 100ml.

The calcination conditions are: calcination at 600°C to 800°C for 1h to 3h, more preferably, calcination at 700°C for 2h.

The calcination is carried out under an argon protective atmosphere.

The vertical graphene/titanium niobium oxide/sulfur-carbon composite material with a three-dimensional porous array structure has a three-dimensional porous array structure, which is very suitable as a negative electrode material for lithium ion batteries.

Compared with the prior art, the present invention has the following advantages and outstanding effects:

In the present invention, the VG/TiNb ₂ O ₇ @SC composite porous array is a thin film material, without additives and binders, and has superior cycle stability and high rate performance; the VG porous conductive substrate has a three-dimensional nanoporous structure, which increases the The electrode/electrolyte contact area shortens the lithium ion transmission path; the sulfur-doped carbon layer coating provides a fast channel for electron transfer between the electrolyte and the electrode, improves the interface, reduces the interface transfer resistance, and thus improves the electron conductivity, Reduces the effects of the material's intrinsic low electronic/ionic conductivity. The composite negative electrode improves the safety performance and cycle performance of lithium ion batteries, and helps to promote the development of lithium metal secondary batteries with high energy density and high stability.

Description of drawings

Fig. 1 is the scanning electron microscope image of the VG/TiNb ₂ O ₇ array prepared in Example 2;

Fig. 2 is the TEM image of the VG/TiNb ₂ O ₇ array obtained in Example 2;

In Fig. 3 a is the scanning electron microscope image of VG/TiNb ₂ O ₇ @SC prepared in Example 2, and b in Fig. 3 is the Ti element distribution spectrum of VG/TiNb ₂ O ₇ @SC prepared in Example 2 Fig. 3, c is the Nb element distribution spectrum of VG/TiNb ₂ O ₇ @SC prepared in Example 2, and d in Fig. 3 is the VG/TiNb ₂ O ₇ @SC prepared in Example 2. O element distribution spectrum, e in Figure 3 is the C element distribution spectrum of VG/TiNb ₂ O ₇ @SC prepared in Example 2, and f in Figure 3 is VG/TiNb ₂ O prepared in Example 2 ₇ The S element distribution spectrum of @SC;

FIG. 4 is a scanning electron microscope image of the VG/TiNb ₂ O ₇ @SC composite nanoporous array prepared in Example 2. FIG.

Detailed ways

The present invention will be described in detail below with reference to the embodiments, but the present invention is not limited thereto.

(1) Preparation method of vertical graphene (VG): The VG array was deposited on carbon cloth in an orderly manner by plasma-enhanced chemical vapor deposition (PECVD) (the microwave frequency was 2.45 GHz and the microwave power was 2 kW). First, carbon was placed in the cavity and its gas pressure was 10 mTorr. Second, after the cavity temperature was raised to 400 °C, hydrogen plasma was generated in the cavity. The hydrogen plasma was passed through a 500 W microwave plasma at a flow rate of 90 sccm. ₂ is produced in the gas stream, and methane is fed into it at the same time. During the whole reaction process, the ratio of hydrogen to methane was 3:2, the reaction time was kept for 2 h, and finally, the VG sample was prepared by cooling to room temperature 25 °C.

(2) Preparation method of VG/TiNb ₂ O ₇ : the VG substrate was dried in an oven for 12 h and weighed. After weighing, the vertical graphene (VG) was used as the growth substrate, and isopropyl titanate (C ₁₂ H ₂₈ O ₄ Ti) and niobium pentachloride (NbCl ₅ ) were used as precursors for a solvothermal reaction. 0.5684g of C ₁₂ H ₂₈ O ₄ Ti and 1.08g of NbCl ₅ were taken and stirred in a beaker for 15 minutes, then transferred to a hydrothermal kettle for reaction at 200° C. for 6 hours, and cooled in the furnace. Then, the sample was washed several times with deionized water and absolute ethanol and dried. Under the protective atmosphere of argon, it was heat-treated and calcined in a tube furnace at 700 °C for 2 h, and the heating rate was 5 °C/min to obtain VG/min. _{TiNb2O7 thin} film sample.

(3) Preparation method of VG/TiNb ₂ O ₇ @SC: 0.5 ml EDOT and 1 g LiClO ₄ were dissolved in 100 ml acetonitrile, and galvanostatic anodic deposition (1 mA cm ⁻² ) was carried out on the prepared VG/TiNb ₂ O ₇ thin film. After PEDOT was deposited, it was calcined in a tube furnace at a high temperature of 700 °C for 2 h (Ar atmosphere) with a heating rate of 5 °C/min to obtain a VG/TiNb ₂ O ₇ @SC three-dimensional porous array.

Example 1

The VG substrate was dried in a vacuum oven. Using isopropyl titanate (C ₁₂ H ₂₈ O ₄ Ti) and niobium pentachloride (NbCl ₅ ) as precursors, a solvothermal reaction was carried out at 200° C. for 6 h, followed by cooling in a furnace. The obtained sample was washed several times with deionized water and absolute ethanol, dried, and calcined at 700 °C for 2 h under an argon protective atmosphere with a heating rate of 5 °C/min to obtain a VG/TiNb ₂ O ₇ thin film sample. Galvanostatic anodic deposition was performed with VG/TiNb ₂ O ₇ as the core in EDOT and LiClO ₄ in acetonitrile solution. After about 10 s, the PEDOT polymer will be uniformly deposited on the VG/TiNb ₂ O ₇ array to form a core-shell structure, and then calcined in a tube furnace at a high temperature of 700 °C for 2 h (Ar atmosphere) to obtain VG/TiNb ₂ O ₇ @SC Three-dimensional porous array.

Example 2

The VG substrate was dried in a vacuum oven. Using isopropyl titanate (C ₁₂ H ₂₈ O ₄ Ti) and niobium pentachloride (NbCl ₅ ) as precursors, a solvothermal reaction was carried out at 200° C. for 6 h, followed by cooling in a furnace. The obtained sample was washed several times with deionized water and absolute ethanol, dried, and calcined at 700 °C for 2 h under an argon protective atmosphere with a heating rate of 5 °C/min to obtain a VG/TiNb ₂ O ₇ thin film sample. Galvanostatic anodic deposition was performed with VG/TiNb ₂ O ₇ as the core in EDOT and LiClO ₄ in acetonitrile solution. After about 20s,

The PEDOT polymer will be uniformly deposited on the VG/TiNb ₂ O ₇ array to form a core-shell structure, and then calcined in a tube furnace at 700 °C for 2 h (Ar atmosphere) to obtain VG/TiNb ₂ O ₇ @SC three-dimensional porous array.

The SEM image of the VG/TiNb ₂ O ₇ array prepared in Example 2 is shown in Figure 1; the TEM image of the VG/TiNb ₂ O ₇ array prepared in Example 2 is shown in Figure 2; Figure 3 In a is the scanning electron microscope image of VG/TiNb ₂ O ₇ @SC prepared in Example 2, and b in FIG. 3 is the Ti element distribution spectrum of VG/TiNb ₂ O ₇ @SC prepared in Example 2, In Fig. 3 c is the Nb element distribution spectrum of VG/TiNb ₂ O ₇ @SC prepared in Example 2, and d in Fig. 3 is O element of VG/TiNb ₂ O ₇ @SC prepared in Example 2 Distribution spectrum, e in Figure 3 is the C element distribution spectrum of VG/TiNb ₂ O ₇ @SC prepared in Example 2, and f in Figure 3 is VG/TiNb ₂ O ₇ @ prepared in Example 2 S element distribution spectrum of SC; FIG. 4 is a scanning electron microscope image of the VG/TiNb ₂ O ₇ @SC composite nanoporous array prepared in Example 2.

As can be seen from the figure, the vertical graphene/titanium niobium oxide/sulfur-carbon composite material with a three-dimensional porous array structure of the present invention includes: graphene nanosheets (VG) grown vertically and intertwined on the substrate to form a three-dimensional nanoporous structure; TiNb ₂ O ₇ (ie TNO) coated _on the graphene nanosheets to form VG/TiNb _{2 O7} nanosheets _; and a sulfur-doped carbon layer ( SC) to form VG/TiNb ₂ O ₇ @SC three-dimensional porous arrays. The thickness of the graphene nanosheet is 5-8 nm, the thickness of the VG/TiNb ₂ O ₇ nano sheet is 20-50 nm, and the thickness of the VG/TiNb ₂ O ₇ @SC three-dimensional porous array finally obtained (ie VG/TiNb ₂ O ₇ @SC core-shell array nanosheet thickness) is 50-120 nm.

Example 3

The VG substrate was dried in a vacuum oven. Using isopropyl titanate (C ₁₂ H ₂₈ O ₄ Ti) and niobium pentachloride (NbCl ₅ ) as precursors, a solvothermal reaction was carried out at 200° C. for 6 h, followed by cooling in a furnace. The obtained sample was washed several times with deionized water and absolute ethanol, dried, and calcined at 700 °C for 2 h under an argon protective atmosphere with a heating rate of 5 °C/min to obtain a VG/TiNb ₂ O ₇ thin film sample. Galvanostatic anodic deposition was performed with VG/TiNb ₂ O ₇ as the core in EDOT and LiClO ₄ in acetonitrile solution. After about 40 s, the PEDOT polymer will be uniformly deposited on the VG/TiNb ₂ O ₇ array to form a core-shell structure, and then calcined in a tube furnace at a high temperature of 700 °C for 2 h (Ar atmosphere) to obtain VG/TiNb ₂ O ₇ @SC Three-dimensional porous array.

Performance Testing

The VG/TiNb ₂ O ₇ @SC three-dimensional porous electrode materials prepared in the above examples 1 to 3 were used as the counter electrode and the working electrode of the coin cell respectively, the metal lithium disc was used as the counter electrode, and 1M LiPF ₆ +EC/DMC (1:1) is the electrolyte. The negative electrode sheet, electrolyte, separator, and counter electrode electrode sheet are sequentially added to the battery case for battery assembly. After assembly, the battery is pressed and sealed in an automatic packaging machine, and the electrochemical test is performed after standing for more than 12 hours. The charge and discharge test is carried out at room temperature. The instrument is a blue battery test system. The test mainly adopts constant current charge and discharge test and cyclic voltammetry test. The constant current charge-discharge test is a very important electrochemical test method, and its main indicators are: specific capacity, rate performance, cycle performance, and Coulombic efficiency. The test voltage range is relative to Li/Li ⁺ 1.0-2.5V, the rate test current is 1C, 2C, 5C, 10C, 20C, 40C, 80C, 160C, and the cycle test current is 10C.

The performance test results are as follows:

The discharge specific capacitances of the VG/TiNb ₂ O ₇ @SC three-dimensional porous electrodes of Example 1, Example 2 and Example 3 were 134mAh/g, 182mAh/g and 165mAh/g at 10C current density, respectively. In addition, after 10,000 cycles, the discharge specific capacity retention rate is over 65%, and the Coulomb efficiency is over 95%. It can be seen that the VG/TiNb ₂ O ₇ @SC three-dimensional porous electrode prepared above has good cycle stability and high Coulombic efficiency after the assembled battery. The discharge specific capacitances of the VG/TiNb ₂ O ₇ @SC three-dimensional porous electrodes of Example 1, Example 2 and Example 3 were 145mAh/g, 225mAh/g and 180mAh/g at a current density of 160C, respectively. It can be seen that the VG/TiNb ₂ O ₇ @SC three-dimensional porous electrode material prepared above has better high rate performance.

The VG conductive substrate has a three-dimensional nanoporous structure, and the nano-ization into electrons and lithium ions increases the electrode/electrolyte contact area and shortens the lithium ion transport path; on the other hand, the three-dimensional porous VG substrate and the sulfur-doped carbon layer are both With high electronic conductivity, it can promote the electronic conduction between particles, thereby improving its electronic/ionic conductivity.

Therefore, the VG/TiNb ₂ O ₇ @SC three-dimensional porous electrode of the present invention has the characteristics of high cycle stability, high rate capability and Coulomb efficiency, etc., making it promising to be a high power density and energy density lithium-ion battery negative electrode for commercial application Material.

Claims (10)

1. A vertical graphene/titanium niobium oxygen/sulfur carbon composite material with a three-dimensional porous array structure is characterized by comprising:

graphene nanosheets vertically and crossly grown on the substrate;

TiNb coated on the graphene nanosheet₂O₇Form VG/TiNb₂O₇Nanosheets;

and coating the VG/TiNb₂O₇A sulfur-doped carbon layer on the nanosheets to form VG/TiNb₂O₇@ S-C three-dimensional porous arrays.

2. The vertical graphene/niobium titanium oxide/sulfur carbon composite material with a three-dimensional porous array structure as claimed in claim 1, wherein the thickness of the graphene nanosheet is 5-8nm, and the VG/TiNb is₂O₇The thickness of the nano-sheet is 20-50nm, and finally the obtained VG/TiNb₂O₇Thickness of the three-dimensional porous array of @ S-C, i.e. VG/TiNb₂O₇The thickness of the @ S-C core-shell array nanosheet is 50-120 nm.

3. The preparation method of the vertical graphene/niobium titanium oxygen/sulfur-carbon composite material with the three-dimensional porous array structure as claimed in claim 1 or 2, characterized by comprising the following steps:

(1) sequentially depositing the graphene array on carbon cloth by a plasma enhanced chemical vapor deposition method to obtain a vertical graphene nanosheet;

(2) drying the vertical graphene nanosheet, taking the vertical graphene nanosheet as a growth substrate, carrying out solvothermal reaction by using isopropyl titanate and niobium pentachloride as precursors, cleaning, drying, carrying out heat treatment and calcining after the reaction is finished, thus obtaining VG/TiNb₂O₇Nanosheets;

(3) 3, 4-ethylenedioxythiophene and LiClO₄Dissolving in acetonitrile, and depositing in constant-current anode to obtain VG/TiNb₂O₇And after PEDOT is deposited on the nano-sheet, calcining the nano-sheet to obtain the vertical graphene/titanium niobium oxide/sulfur carbon composite material with the three-dimensional porous array structure.

4. The method according to claim 3, wherein in the step (1), the microwave frequency is 2.2 to 2.6GHz and the microwave power is 1.5kW to 2.5kW in the plasma enhanced chemical vapor deposition method.

5. The preparation method according to claim 3, wherein in the step (2), the mass ratio of isopropyl titanate to niobium pentachloride is 1: 1.5 to 2.5.

6. The method according to claim 3, wherein in the step (2), the reaction conditions of the solvothermal reaction are as follows: reacting for 4-8 h at 180-220 ℃.

7. The method according to claim 3, wherein in the step (2), the conditions for the heat treatment calcination are as follows: calcining for 1 to 3 hours by heat treatment at the temperature of 600 to 800 ℃;

the heat treatment calcination is carried out under the protection atmosphere of argon.

8. The method according to claim 3, wherein in the step (3), the 3, 4-ethylenedioxythiophene and LiClO are used₄The mixture ratio of the acetonitrile to the acetonitrile is 0.3 mL-0.7 mL: 0.5 g-1.5 g: 80mL to 120 mL.

9. The method according to claim 3, wherein in the step (3), the calcination is carried out under the following conditions: calcining for 1 to 3 hours at the temperature of 600 to 800 ℃;

the calcination is carried out under the protection atmosphere of argon.

10. The application of the vertical graphene/titanium niobium oxide/sulfur carbon composite material with the three-dimensional porous array structure according to claim 1 as a lithium ion battery anode material.

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