1. A preparation method of a titanium dioxide/three-dimensional graphene composite electrode material is characterized by comprising the following steps:

carrying out ultrasonic treatment on graphene oxide, glycolic acid and titanyl sulfate to obtain a mixed solution;

heating the mixed solution to 180 ℃, carrying out hydrothermal reaction for 12 hours, then carrying out solid-liquid separation to obtain a solid, washing and drying the solid to obtain a primary product;

calcining the product at 450-700 ℃ for 4 hours to obtain the titanium dioxide/three-dimensional graphene composite electrode material.

2. The method for preparing the titanium dioxide/three-dimensional graphene composite electrode material according to claim 1, wherein the concentration of the graphene oxide is 2mg ml^-1-20mg ml^-1。

3. The method for preparing the titanium dioxide/three-dimensional graphene composite electrode material according to claim 1, wherein the concentration of the glycolic acid is 1mg ml^-1-5mg ml^-1。

4. The method for preparing the titanium dioxide/three-dimensional graphene composite electrode material according to claim 1, wherein the concentration of the titanyl sulfate is 1mg ml^-1。

5. The method for preparing the titanium dioxide/three-dimensional graphene composite electrode material according to claim 1, wherein the time of the ultrasonic treatment is 1-3 h.

6. The preparation method of the titanium dioxide/three-dimensional graphene composite electrode material according to claim 1, wherein the calcination method is to reduce the three-dimensional graphene oxide by an aluminum reduction method through a two-temperature-zone vacuum furnace.

7. The preparation method of the titanium dioxide/three-dimensional graphene composite electrode material according to claim 6, wherein the aluminum powder is placed in a high-temperature area of a dual-temperature area, and the titanium dioxide/three-dimensional graphene oxide is placed in a low-temperature area of the dual-temperature area.

8. The method for preparing the titanium dioxide/three-dimensional graphene composite electrode material according to claim 7, wherein the temperature of the high-temperature region is 800 ℃, and the temperature of the low-temperature region is 450-700 ℃.

9. A titanium dioxide/three-dimensional graphene composite electrode material, which is obtained by the production method according to any one of claims 1 to 8.

10. Use of the titanium dioxide/three-dimensional graphene composite electrode material according to claim 9 in a battery.

Background

Facing global energy shortages and environmental pollution issues, the high efficiency of energy harvesting, conversion and storage devices is an urgent need when new technologies are created. Lithium ion batteries, which are the most widely used for energy conversion and storage, are one of the most promising energy storage devices for various portable electronic devices. For the next generation of lithium ion batteries, designing and synthesizing functional battery materials that can reduce cost, increase capacity, and improve rate performance and cycle performance is a key goal. In the study of lithium ion batteries, it is important to study the negative electrode of the lithium ion battery, because the abdominal muscle of the battery can greatly affect the battery performance of the lithium ion battery. Transition metal oxides have attracted considerable attention in lithium ion batteries and supercapacitors due to their superior electrochemical properties. Titanium dioxide is an early-researched metal oxide negative electrode material, and becomes a research hotspot in recent years due to the advantages of stable structure, excellent cycle performance, low price, environmental friendliness, high safety and the like

Titanium dioxide has various crystal structures, including rutile, anatase, brookite and the like, wherein anatase and brookite are common cathode materials for manufacturing lithium ion batteries in the industry at present. The anatase type crystal lattice structure is beneficial to capturing more electrons because of more defects and vacancies, and has easier Li + insertion and extraction and higher electrical activity. The titanium dioxide material has low electronic conductivity, and the diffusion coefficient of lithium ions in the titanium dioxide material is small, so that more research works aim at synthesizing the titanium dioxide material with a nano size, and meanwhile, the good structural morphology is also beneficial to improving the electrochemical performance of the titanium dioxide, and on the other hand, the titanium dioxide is compounded with a conductive carbon material, a metal oxide material and the like, so that the conductivity of the material is improved, and further, the specific capacity of the titanium dioxide as a negative electrode material is improved.

When the existing titanium dioxide composite material with the anatase structure is used as a negative electrode material of a lithium ion battery, the discharge capacity of the lithium ion battery is low, and the cycle stability is poor.

Disclosure of Invention

Based on the defects of the prior art, it is necessary to provide a preparation method of a titanium dioxide/three-dimensional graphene composite electrode material, the titanium dioxide/three-dimensional graphene composite electrode material and an application, wherein the preparation method is simple and can improve the discharge specific capacity and the cycle stability of a lithium ion battery.

The preparation method of the titanium dioxide/three-dimensional graphene composite electrode material comprises the following steps:

carrying out ultrasonic treatment on graphene oxide, glycolic acid and titanyl sulfate to obtain a mixed solution;

heating the mixed solution to 180 ℃, carrying out hydrothermal reaction for 12 hours, then carrying out solid-liquid separation to obtain a solid, washing and drying the solid to obtain a primary product;

calcining the product at 450-700 ℃ for 4 hours to obtain the titanium dioxide/three-dimensional graphene composite electrode material.

The application also provides a titanium dioxide/three-dimensional graphene composite electrode material prepared by the method, and the application also provides application of the titanium dioxide/three-dimensional graphene composite electrode material in a battery.

Optionally, the concentration of the graphene oxide is 2mg ml^-1-20mg ml^-1。

Optionally, the concentration of glycolic acid is 1mg ml^-1-5mg ml^-1。

Optionally, the concentration of the titanyl sulfate is 1mg ml^-1。

Optionally, the time of the ultrasonic treatment is 1h-3 h.

Optionally, the calcining mode is to reduce the three-dimensional graphene oxide by an aluminum reduction method through a dual-temperature-zone vacuum furnace.

Optionally, the aluminum powder is placed in a high-temperature area of a double-temperature area, and the titanium dioxide/three-dimensional graphene oxide is placed in a low-temperature area of the double-temperature area.

Optionally, the temperature of the high temperature zone is 800 ℃ and the temperature of the low temperature zone is 450-700 ℃.

The titanium dioxide/three-dimensional graphene composite electrode material provided by the application has the following advantages:

1. the preparation process of the titanium dioxide/three-dimensional graphene composite electrode material is simple, and the raw material cost is low.

2. The titanium dioxide/three-dimensional graphene composite electrode material prepared by the method has high charge-discharge specific capacity and excellent cycling stability.

Drawings

In order to more clearly describe the embodiments of the present application, a brief description will be given below of the relevant drawings. It is understood that the drawings in the following description are only for illustrating some embodiments of the present application, and that a person skilled in the art may also derive from these drawings many other technical features not mentioned herein.

Fig. 1 is an X-ray diffraction photograph of the titanium dioxide/three-dimensional graphene composite electrode material prepared in example 1;

fig. 2 is a raman test chart of the titanium dioxide/three-dimensional graphene composite electrode material prepared in example 1;

fig. 3 is a scanning electron microscope image of the titanium dioxide/three-dimensional graphene composite electrode material prepared in example 1;

FIG. 4 is a TEM image of the Titania/three-dimensional graphene composite electrode material prepared in example 1

Fig. 5 is a specific capacity graph of the lithium ion battery of the titanium dioxide/three-dimensional graphene composite electrode material prepared in example 1 at current densities of 0.1C, 0.2C and 0.5C;

fig. 6 is a test chart of the lithium ion battery of the titanium dioxide/three-dimensional graphene composite electrode material prepared in example 1, which is cycled 300 times at current densities of 0.1C, 0.2C and 0.5C.

Detailed Description

The present application will be described in detail below with reference to the accompanying drawings.

The preparation method of the titanium dioxide/three-dimensional graphene composite electrode material, the titanium dioxide/three-dimensional graphene composite electrode material and the application thereof will be further described in detail below.

The preparation method of the titanium dioxide/three-dimensional graphene composite electrode material of the embodiment comprises the following steps:

providing a mixed solution, wherein the solution contains graphene oxide, glycolic acid and titanyl sulfate, and carrying out ultrasonic treatment on the mixed solution;

heating the mixed solution to 180 ℃, carrying out hydrothermal reaction for 12 hours, then carrying out solid-liquid separation to obtain a solid, washing and drying the solid to obtain a primary product;

and calcining the product to obtain the titanium dioxide/graphene composite electrode material.

The application also provides a titanium dioxide/three-dimensional graphene composite electrode material prepared by the method.

Optionally, the raw materials are mixed according to different concentrations, which are respectively: graphene oxide, glycolic acid and titanyl sulfate.

The concentration of the optional mixed solution of ethanol and deionized water is 0 wt% -100 wt%.

The optional calcination temperature is 450-700 ℃ in the low temperature region of the two temperature regions and 800 ℃ in the high temperature region. An alternative calcination time was 4 h.

Implementation mode one

a) Will contain 4mg ml^-11mg ml of graphene oxide (g)^-12mg ml of glycolic acid^-1The mixed solution of titanyl sulfate was sufficiently stirred and subjected to ultrasonic treatment for 3 hours.

b) Heating the mixed solution to 180 ℃, preserving the temperature for 12 hours, and then carrying out solid-liquid separation to obtain a solid.

c) The solid was immersed in a 20 wt% aqueous alcoholic solution for 6 hours and then freeze-dried to obtain the crude product.

d) And placing the primary product in a low-temperature area of a double-area vacuum furnace, setting the temperature to be 550 ℃, and placing the aluminum powder in a high-temperature area of the double-area vacuum furnace, setting the temperature to be 800 ℃. The temperature was maintained for 4 hours.

Second embodiment

a) Will contain 4mg ml^-13mg ml of graphene oxide (g)^-12mg ml of glycolic acid^-1Mixed liquid of titanyl sulfateStirring and ultrasonic processing for 3 hours.

b) Heating the mixed solution to 180 ℃, preserving the temperature for 12 hours, and then carrying out solid-liquid separation to obtain a solid.

c) The solid was immersed in a 30 wt% aqueous alcoholic solution for 6 hours and then freeze-dried to obtain the crude product.

d) And placing the primary product in a low-temperature area of a double-area vacuum furnace at the temperature of 600 ℃, and placing the aluminum powder in a high-temperature area of the double-area vacuum furnace at the temperature of 800 ℃. The temperature was maintained for 4 hours.

Third embodiment

a) Will contain 4mg ml^-15mg ml of graphene oxide (g)^-12mg ml of glycolic acid^-1The mixed solution of titanyl sulfate was sufficiently stirred and subjected to ultrasonic treatment for 3 hours.

b) Heating the mixed solution to 180 ℃, preserving the temperature for 12 hours, and then carrying out solid-liquid separation to obtain a solid.

c) The solid was immersed in a 50 wt% aqueous alcoholic solution for 6 hours and then freeze-dried to obtain the crude product.

d) And placing the primary product in a low-temperature area of a double-area vacuum furnace, setting the temperature to be 700 ℃, and placing the aluminum powder in a high-temperature area of the double-area vacuum furnace, setting the temperature to be 800 ℃. The temperature was maintained for 4 hours.

The applicant has found through tests that graphene oxide is reduced to reduced graphene oxide after heat treatment,

as shown in figure 1, the TiO in anatase form prepared by the technical scheme of the application₂。

Referring to fig. 2, after annealing, the graphene oxide is reduced to graphene.

Referring to FIG. 3, TiO₂Nano particles are uniformly loaded on TiO₂Surface of/GCM, and TiO₂The three-dimensional cross-linked structure of the/GCM is well maintained, and the pore structure is uniformly distributed to a great extent.

Referring to fig. 4, it is shown that the titanium dioxide nanoparticles subjected to the dual-temperature-zone aluminum reduction treatment have a highly crystallized lattice-stripe ordered structure at the center, a disordered layer with a thickness of 1-2nm is formed near the surface of the nanoparticles, the whole titanium dioxide nanoparticles form an ordered/disordered core-shell structure, and the selected-zone electron diffraction surface of the corresponding zone shows that the prepared titanium dioxide nanoparticles have an Anatase (antase) crystal form.

As shown in FIG. 5, the voltage of the sample ranges from 1 to 3V (relative to Li/Li)⁺) The specific capacities of the components are 386,324,286,235,205mAh g respectively under different multiplying powers of 0.1C, 0.2C, 0.5C, 1C and 2C^- 。

Referring to fig. 6, the capacity retention rate of the sample after 300 cycles at current densities of 0.1C, 0.2C, 0.5C, 1C, and 2C remained above 98%.

Finally, it should be noted that those skilled in the art will appreciate that embodiments of the present application present many technical details for the purpose of enabling the reader to better understand the present application. However, the technical solutions claimed in the claims of the present application can be basically implemented without these technical details and various changes and modifications based on the above-described embodiments. Accordingly, in actual practice, various changes in form and detail may be made to the above-described embodiments without departing from the spirit and scope of the present application.