CN-122025433-A - Preparation method of graphene strip modified bismuth-based composite anode material and electrochemical energy storage application thereof

Abstract

The invention discloses a preparation method of a graphene strip modified bismuth-based composite anode material and electrochemical energy storage application thereof, and particularly relates to modification and technical application of an anode material of a supercapacitor. Dispersing graphene strips in a solvent, adding a bismuth source, performing solvothermal reaction, and performing suction filtration and vacuum drying after the reaction is finished to obtain the graphene strip modified bismuth-based composite material. The electrode material is prepared by mixing the composite anode material, the conductive agent and the binder, coating the mixture on a conductive substrate and tabletting. The composite material prepared by the method has good structural stability and electrochemical performance, and can be used for preparing the anode material of the supercapacitor.

Inventors

• DAI FANGNA
• MIAO QIUSHI
• FAN ZHUANGJUN
• WEI TONG
• WANG GUANWEN

Assignees

• 中国石油大学(华东)

Dates

Publication Date

20260512

Application Date

20260319

Claims (8)

1. 1. A preparation method of a graphene strip modified bismuth-based composite material is characterized by comprising the specific steps of dispersing graphene strips in a solvent to obtain a dispersion liquid, adding a bismuth source into the dispersion liquid, uniformly mixing, performing solvothermal reaction, filtering an obtained product after the reaction is finished, and performing vacuum drying to obtain the graphene strip modified bismuth-based composite material.
2. 2. The preparation method of the graphene strips is characterized in that the graphene strips are obtained by spraying, freezing and drying graphene oxide, wherein the graphene oxide is prepared by a modified Hummers method according to the specific preparation scheme, the graphene oxide is mixed with concentrated sulfuric acid under the ice bath condition, potassium permanganate is added for oxidation reaction, deionized water and hydrogen peroxide are added for terminating reaction after the reaction is finished, the reaction is centrifugally washed to be neutral and dried to obtain graphene oxide, and graphene oxide dispersion liquid is sprayed into liquid nitrogen through a spraying device for quick freezing and then freeze drying, so that the graphene strips are obtained.
3. 3. The method according to claim 1, wherein the bismuth source is one or more of bismuth nitrate, bismuth chloride and bismuth acetate.
4. 4. The preparation method of claim 1, wherein the mass ratio of the bismuth source to the graphene strips is 4:1-20:1.
5. 5. The method according to claim 1, wherein the solvothermal reaction temperature is 180-220 ℃ and the reaction time is 12-48 h.
6. 6. The method according to claim 1, wherein the solvent is ethanol, water, ethylene glycol or a mixed solvent thereof.
7. 7. The preparation method of the supercapacitor anode material is characterized by comprising the following steps of dispersing the graphene strip modified bismuth-based composite material, the conductive agent and the binder prepared by the method of claim 1 in ethanol to prepare electrode slurry, coating the electrode slurry on the surface of a conductive substrate, and drying and tabletting to obtain the supercapacitor anode material.
8. 8. The method of claim 7, wherein the conductive substrate is nickel foam, carbon cloth, or stainless steel mesh.

Description

Preparation method of graphene strip modified bismuth-based composite anode material and electrochemical energy storage application thereof Technical Field The invention relates to the technical field of electrochemical energy storage materials, in particular to a preparation method of a graphene strip modified bismuth-based composite anode material and an electrochemical energy storage application thereof. Background The super capacitor is an important electrochemical energy storage device, has the advantages of high power density, high charge and discharge speed, long cycle life and the like, and has wide application prospects in the fields of new energy automobiles, smart grids, portable electronic equipment and the like. However, the energy density is still relatively low compared to conventional electrochemical cells, especially critical for the development of high capacity, high rate anode materials. At present, the carbon material has larger specific surface area and good conductivity, and has good multiplying power characteristic and stability as an energy storage anode material, so that the carbon material has been preliminarily approved and popularized in the market. However, the energy storage mechanism mainly depends on an electric double-layer capacitor, so that the specific capacity is relatively low, and the bottleneck of low energy density of the super capacitor cannot be broken through. To further improve the energy storage properties of the negative electrode, researchers have gradually introduced bismuth-based materials with reversible redox reaction characteristics into the electrode system. The prior art generally improves the electrochemical performance of bismuth-based materials by constructing conductive carbon-based composite structures. For example, patent CN113258025A discloses a bismuth-based negative electrode for a high-performance aqueous battery, which is formed by growing bismuth-based nanostructures on a porous conductive carbon substrate, thereby improving the cycling stability and specific capacity of the electrode. Patent CN114784256B discloses a bismuth-based composite anode material, and the rate capability and the cycle stability of the material are improved by coating bismuth nanoparticle structures with carbon. In addition, patent CN118782394a improves the conductivity and energy storage properties of the material by constructing Bi 2O3/Bi2S3 heterogeneous composite structure and introducing conductive carbon material. Although the technology improves the electrochemical performance of bismuth-based materials to a certain extent, the problems of limited electron transmission paths, easy agglomeration of active substances, insufficient stability of conductive structures and the like still exist, so that the utilization rate of active sites is low. Accordingly, there is still a need for further development of bismuth-based anode materials capable of constructing stable electron transport paths and improving the efficiency of electrochemical reactions. Disclosure of Invention The invention provides a graphene strip modified bismuth-based composite material, a preparation method and application thereof, and aims to solve the problems of poor conductivity and insufficient structural stability in a circulating process of bismuth-based materials in the prior art. The preparation method comprises the following steps: The preparation method comprises the steps of carrying out banding treatment on graphene oxide by adopting a spray-freezing technology to obtain graphene bands, carrying out solvothermal reaction on the graphene bands and a bismuth source after ultrasonic dispersion and stirring and mixing uniformly in ethanol, and carrying out suction filtration, washing and vacuum drying after the reaction is finished to obtain the bismuth-based composite material modified by the graphene bands. Further, the bismuth source adopts one or more of bismuth nitrate, bismuth chloride and bismuth acetate. Further, the mass fraction of the graphene strips is 5% -20%. Further, the temperature of the solvothermal reaction is 180-220 ℃, and the reaction time is 12-48 hours. Further, the temperature of the vacuum drying is 80 ℃, and the vacuum drying treatment time is 12 h. The invention also discloses the graphene strip modified bismuth-based composite material prepared by the preparation method. The invention also discloses a preparation method of the supercapacitor anode material, which comprises the following steps: And mixing the graphene strip modified bismuth-based composite material, conductive acetylene black and a PTFE binder in a solvent to prepare slurry, coating the slurry on the surface of a conductive substrate, and tabletting to obtain the supercapacitor negative electrode material. Preferably, the conductive substrate adopts foam nickel, and the solvent adopts absolute ethyl alcohol. Compared with the prior art, the invention has the following beneficial effects: The pre