Method for preparing flow battery electrode by using waste paper recycled carbon material

Abstract

The invention discloses a method for preparing a flow battery electrode by using a waste paper recycled carbon material, and belongs to the technical field of functional materials and preparation thereof. The invention solves the problems of insufficient conductivity, small porosity, high preparation cost, complex process, poor environmental protection property and the like of the existing carbon dioxide flow battery electrode material. Waste paper is used as a carbon source, a porous carbon fiber material is obtained through freezing, freeze drying and carbonization treatment, the porous carbon fiber material and a high-conductivity material are ground and mixed to serve as an electrode base material, and the electrode base material which is high in hydrophobicity, high in specific surface area, high in adsorption and desorption performance and high in ductility is obtained after shaping. And the electrode material has good electrochemical physical properties such as low reaction internal resistance and good cycle performance. The porous carbon fiber material obtained by carbonizing waste paper as a carbon source has excellent ductility and electrochemical performance, can effectively replace a common electrode material, is wide in raw material source, and realizes effective utilization of waste materials.

Description

Technical Field

[0001] The present invention relates to a method for preparing a flow battery electrode by recycling carbon materials from waste paper, belonging to the technical field of functional materials and their preparation. Background Art

[0002] As a method for carbon dioxide utilization, the carbon dioxide flow battery technology has the advantages of low cost, scalability, high safety, high efficiency and stability, and long cycle life. However, the flow battery technology based on the electrode as the reaction carrier highly depends on the characteristics of the electrode itself. The carbon aerogel electrode material has the advantages of wide raw material sources, good hydrophobicity, and high specific surface area, and is designed and used as the matrix of the positive electrode material for carbon dioxide flow batteries. However, the existing common flow battery electrode materials such as graphite and metal materials have defects such as insufficient conductivity, high reaction impedance, complex preparation process, high cost, and small porosity of the porous medium, which will limit their application in batteries. And various waste papers are widely distributed in all aspects of social production and life, resulting in serious waste of waste paper resources. Considering the low collection cost and easy treatment characteristics of waste paper, it is planned to prepare a porous carbonaceous material as the electrode material substrate from waste paper to improve the overall efficiency and conductivity of the carbon dioxide flow battery and expand its scalable promotion range. Summary of the Invention

[0003] In order to solve the problems of insufficient conductivity, small porosity, high preparation cost, complex process, and poor environmental protection of the existing carbon dioxide flow battery electrode materials, the present invention provides a method for preparing a flow battery electrode by recycling carbon materials from waste paper.

[0004] The technical solution of the present invention is as follows:

[0005] One of the purposes of the present invention is to provide a method for preparing a carbon aerogel electrode, which includes the following steps:

[0006] S1. Cut the waste fiber material into pieces and soak it in deionized water, stir to obtain a paste-like slurry, and obtain porous carbon material powder through freezing, freeze-drying and high-temperature carbonization treatment;

[0007] S2. Grind and mix the porous carbon material and the highly conductive material to obtain an electrode substrate;

[0008] S3. Mix the electrode substrate with a cross-linking agent, coat it on a current collector, and air-dry to obtain a carbon aerogel electrode.

[0009] Further defined, the waste fiber material in S1 is waste paper.

[0010] Further defined, the freezing temperature in S1 is -26°C and the time is 3h.

[0011] Further limitation: in S1, the freeze-drying temperature is -50°C and the time is 36 h.

[0012] Further limitation: in S1, the high-temperature carbonization process is as follows: under argon protection, the temperature is raised to 400°C at a rate of 2°C / min and held for 1 h; then the temperature is raised to 900°C at a rate of 5°C / min and held for 1 h, and then naturally cooled to room temperature.

[0013] Further limitation: in S2, the highly conductive material is carbon nanotubes.

[0014] Further limitation: in S2, the mass ratio of the porous carbon material to the highly conductive material is 10:(1 - 20).

[0015] Further limitation: in S3, the cross-linking agent is polytetrafluoroethylene (PTFE); the current collector is carbon cloth or copper mesh; the mass ratio of the electrode substrate to the cross-linking agent is 6:1.

[0016] The second object of the present invention is to provide a carbon aerogel electrode prepared by the above method.

[0017] The third object of the present invention is to provide an application of the above carbon aerogel electrode, specifically for preparing a carbon dioxide flow battery.

[0018] Beneficial effects:

[0019] In the present invention, waste paper is used as a carbon source, and through freezing, freeze-drying and carbonization treatments, a porous carbon fiber material is obtained. It is ground and mixed with a highly conductive material as an electrode substrate, and after shaping, an electrode material with high hydrophobicity, high specific surface area, high adsorption and desorption properties, high ductility, and good electrochemical properties such as low reaction internal resistance and good cycle performance is obtained. Moreover, the porous carbon fiber material obtained by carbonizing waste paper as a carbon source has excellent ductility and electrochemical performance, and the raw material source is wide, the preparation process is simple, it can effectively replace common electrode materials, avoid common environmental pollution problems, and at the same time realize the effective utilization of waste materials. Brief description of the drawings

[0020] Figure 1 It is a process flow diagram for preparing the electrode material of the present invention;

[0021] Figure 2 It is a scanning electron microscope image (different positions and different magnifications) of the electrode material prepared in Example 1;

[0022] Figure 3 It is an X-ray diffraction analysis diagram of the electrode material prepared in Example 1 and freeze-dried waste paper;

[0023] Figure 4Fourier transform infrared spectroscopy analysis chart of the electrode material and freeze-dried waste paper prepared in Example 1;

[0024] Figure 5 Carbon dioxide adsorption and desorption curve of the electrode material prepared in Example 1;

[0025] Figure 6 Specific surface area curve of the electrode material prepared in Example 1. Detailed implementation manners

[0026] To make the above objects, features and advantages of the present invention more obvious and understandable, the following detailed description of the specific implementation manners of the present invention will be given in conjunction with the embodiments of the specification.

[0027] In the following description, many specific details are set forth to fully understand the present invention. However, the present invention can also be implemented in other ways different from those described herein. Those skilled in the art can make similar generalizations without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0028] Secondly, the so-called "one embodiment" or "embodiment" herein refers to a specific feature, structure or characteristic that can be included in at least one implementation manner of the present invention. The appearances of "in one embodiment" in different places in this specification do not all refer to the same embodiment, nor are they separate or alternative embodiments that exclude each other with other embodiments.

[0029] The experimental methods used in the following embodiments are all conventional methods unless otherwise specified. The materials, reagents, methods and instruments used, unless otherwise specified, are all conventional materials, reagents, methods and instruments in the art, and those skilled in the art can obtain them through commercial channels.

[0030] Example 1:

[0031] Combined with Figure 1 , the method for preparing a flow battery electrode using waste paper recycled carbon material in this embodiment is carried out according to the following steps:

[0032] S1: Cut 30 g of waste paper into pieces and soak it in 400 mL of deionized water for 24 h, and stir evenly with a magnetic stirrer to obtain a paste-like pulp.

[0033] S2: Freeze the paste-like pulp at -26 °C for 3 h, and then put it into a freeze dryer and freeze-dry it at -50 °C for 36 h to obtain a porous fiber aerogel, named freeze-dried waste paper.

[0034] S3: Under argon protection, heat it up to 400 °C at a rate of 2 °C / min, and keep it at this temperature for 1 h; then heat it up to 900 °C at a rate of 5 °C / min, keep it at this temperature for 1 h, naturally cool it to room temperature, and grind it into powder to obtain a black carbon aerogel electrode substrate.

[0035] S4: Mix 0.5 g of the electrode substrate with 0.1 ml of polytetrafluoroethylene (PTFE) crosslinking agent and 0.1 g of carbon nanotubes, and coat them on the carbon cloth current collector at a loading amount of 0.015 g / cm 2 and air-dry it naturally to obtain the carbon aerogel electrode material.

[0036] Characterize the microstructure of the obtained electrode material above. The SEM photograph is as Figure 2 shown. It can be seen from Figure 2 that the carbonized waste paper-based carbon aerogel has a porous and interconnected 3D network. The carbonized carbon aerogel fibers are tightly cross-linked with each other, and the fiber lengths are equal in each part. The fiber size is reduced to about 3.76 μm.

[0037] Figure 3 is the X-ray diffraction analysis diagram of the electrode material prepared in Example 1 and freeze-dried waste paper. It can be seen from the figure that the three characteristic peaks of freeze-dried waste paper are located at 14.97°, 16.72° and 22.86° respectively, corresponding to the typical (110), (110) and (020) planes. After the freeze-dried waste paper is carbonized, these peaks of the obtained electrode material disappear, indicating that the crystal structure of the raw material is destroyed during the carbonization process, forming amorphous carbon.

[0038] Figure 4 is the Fourier transform infrared spectroscopy analysis diagram of the electrode material prepared in Example 1 and freeze-dried waste paper. Among them, the carbon aerogel obtained after carbonization of waste paper is on the left; the analysis diagram of untreated freeze-dried waste paper is on the right. It can be seen from the figure that the freeze-dried waste paper shows the main absorption peaks of functional groups such as C=O, C-O, C-H and O-H. After the freeze-dried waste paper is carbonized, the absorption peaks of these functional groups of the obtained electrode material become weak or even disappear, thus indicating its hydrophobicity and showing a high degree of carbonization of the raw material.

[0039] Test the carbon dioxide adsorption and desorption performance of the electrode material prepared in Example 1 under standard conditions. The test results are as Figure 5 shown. It can be seen from the figure that the electrode material prepared in Example 1 has good carbon dioxide adsorption performance.

[0040] Perform BET test on the electrode material prepared in Example 1. The pore width and specific surface area curve is as Figure 6 shown. It can be obtained from the figure that the specific surface area of the electrode material is 275 m 2 / g, having a relatively high specific surface area.

[0041] In summary, the electrode material provided by the present invention has the advantages of low cost, simple process, high porosity, high hydrophobicity, etc.

[0042] The above are only the preferred specific embodiments of the present invention. These specific embodiments are different implementation manners based on the overall concept of the present invention, and the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A preparation method of a carbon aerogel electrode, characterized in that Including: S1. Cut the waste fiber material into pieces, soak it in deionized water, and stir to obtain a paste-like slurry. Subject the paste-like slurry to freezing, freeze-drying, and high-temperature carbonization treatments to obtain porous carbon material powder; S2. Grind and mix the porous carbon material and the highly conductive material to obtain an electrode substrate; S3. Mix the electrode substrate with a crosslinking agent, coat it on a current collector, and air-dry to obtain a carbon aerogel electrode.

2. The preparation method according to claim 1, characterized in that, In S1, the waste fiber material is waste paper.

3. The preparation method according to claim 1, wherein In S1, the freezing temperature is -26°C and the time is 3 h.

4. The preparation method according to claim 1, wherein In S1, the freeze-drying temperature is -50°C and the time is 36 h.

5. The preparation method according to claim 1, characterized in that, In S1, the high-temperature carbonization process is as follows: Under argon protection, heat up to 400°C at a rate of 2°C / min and hold for 1 h; then heat up to 900°C at a rate of 5°C / min and hold for 1 h, and naturally cool to room temperature.

6. The preparation method according to claim 1, wherein, In S2, the highly conductive material is carbon nanotubes.

7. The preparation method according to claim 1, characterized in that, In S2, the mass ratio of the porous carbon material to the highly conductive material is 10:(1 - 20).

8. The preparation method according to claim 1, wherein In S3, the crosslinking agent is polytetrafluoroethylene; the current collector is carbon cloth or copper mesh; the mass ratio of the electrode substrate to the crosslinking agent is 6:

1.

9. A carbon aerogel electrode prepared by the method according to any one of claims 1 to 8.

10. Use of the carbon aerogel electrode according to claim 9, characterized in that, For preparing a carbon dioxide flow battery.

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