Method for preparing supercapacitor electrode material based on vermiculite-assisted air carbonization
By using vermiculite-assisted carbonization in an air atmosphere to prepare porous carbon materials, the problems of high equipment cost and high cost in preparing porous carbon materials in an inert atmosphere are solved, realizing the economical and simple preparation of high-performance electrode materials and improving the electrochemical performance of supercapacitors.
Patent Information
- Application Number
- CN202511617539.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-06
- Publication Date
- 2026-02-24
AI Technical Summary
Existing methods for preparing porous carbon materials are carried out under an inert atmosphere, which requires sophisticated equipment, is costly, and involves complex processes, making it difficult to achieve economical and rapid preparation of high-performance electrode materials.
Vermiculite was used as a functionalizing agent and mixed with a carbon precursor in an air atmosphere. The flame-retardant properties of vermiculite and the dilution of combustible gases by interlayer water vapor, combined with the etching effect of oxygen in the air, were used to prepare porous carbon materials, which simplified the process and improved the pore structure and oxygen-containing functional groups.
Porous carbon materials were successfully prepared in an air atmosphere, reducing equipment requirements and energy consumption, improving the electrochemical performance and specific capacitance of the materials, increasing raw material utilization, and the process was simple and economical.
Smart Images
Figure CN121565693A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of electrode material technology for supercapacitors, and particularly relates to a method for preparing supercapacitor electrode materials based on vermiculite-assisted air carbonization. Background Technology
[0002] Developing and utilizing green, clean, and renewable new energy sources is the core path to overcoming resource and environmental constraints and achieving sustainable development. Supercapacitors, as key energy storage devices in the new energy system, are leveraging their unique advantages to become an important support for connecting new energy power generation and optimizing energy utilization efficiency. Porous carbon, as the core material of supercapacitor electrodes, directly determines the energy storage performance, cost, and environmental attributes of the device, and is the core foundation for promoting the development of supercapacitors towards higher efficiency and lower cost.
[0003] However, most porous carbon materials are prepared by carbonization under an inert atmosphere, which requires sophisticated equipment, increases resource consumption and cost, and is complex and time-consuming. Therefore, developing a simple, rapid, and economical new method for preparing porous carbon and using it as a high-performance electrode material is of great significance.
[0004] Global vermiculite reserves are approximately 600 million tons, and the price is roughly 700 yuan per ton, making it relatively inexpensive. Vermiculite is a group of hydrated octahedral iron-aluminum-magnesium platy or mica-based silicate minerals, composed of layered minerals such as chlorite, hydromica, and kaolinite. Its main components are SiO2, MgO, Fe2O3, Al2O3, FeO, and H2O, as well as small amounts of CrO3, BaO, MnO, P2O5, and S. In an air atmosphere, when vermiculite is mixed with a carbon precursor, the interlayer spacing of the vermiculite gradually increases with increasing temperature. The water vapor generated by the endothermic reaction of water in the layered structure of the vermiculite effectively dilutes the concentration of combustible gases surrounding the carbon material. Furthermore, vermiculite's dense, layered structure effectively reduces the transport of external oxygen into the interior, and its abundant oxides can coat the surface of carbon precursors, preventing oxidative combustion and thus serving as a flame retardant. Simultaneously, vermiculite's rich composition allows it to be used as a functionalizing agent. Therefore, utilizing vermiculite's flame-retardant properties in conjunction with its activation and template-like functionalization effects provides an effective pathway for preparing porous carbon through carbonization in an air atmosphere. Summary of the Invention
[0005] To overcome the shortcomings of existing technologies, the purpose of this invention is to provide a method for preparing supercapacitor electrode materials based on vermiculite-assisted air carbonization. This method utilizes the flame-retardant properties of vermiculite and its synergistic activation and template functions to protect the carbon precursor from complete burn-off during high-temperature carbonization in air. Simultaneously, it utilizes the oxygen in the air to etch and create pores in the carbon skeleton, thereby preparing a porous carbon material with abundant pore structure and oxygen-containing functional groups. This material is used as a supercapacitor electrode material and exhibits excellent electrochemical performance.
[0006] To achieve the above objectives, the present invention provides the following technical solution:
[0007] A method for preparing supercapacitor electrode materials based on vermiculite-assisted air carbonization includes the following steps:
[0008] 1) Take carbon precursor and vermiculite, mix them evenly in distilled water, then put them in a crucible and dry them in an oven;
[0009] 2) Place the crucible in a muffle furnace and heat it to 600-1000℃ at a heating rate of 1-10℃ / min, so that it is carbonized at high temperature in air atmosphere, hold it at the temperature for 0.5-1.5h, and then cool it naturally to room temperature.
[0010] 3) Remove the crucible, wash away vermiculite and impurities with 40wt% to 60wt% hydrofluoric acid, wash with water until neutral, and put the obtained sample into an oven to dry.
[0011] The mass ratio of vermiculite to carbon precursor is (3~10):1, the carbon precursor can be 0.2~0.4g, and the distilled water is 1~4ml.
[0012] The drying process described in step 1) involves drying in an oven at 80-100°C until the distilled water has completely evaporated.
[0013] The vermiculite mentioned is one or more of the following: golden vermiculite, silvery-white vermiculite, and milky-white vermiculite.
[0014] The carbon precursor is one or more of coal, biomass, polymer, coal tar pitch, and metal-organic frameworks.
[0015] The coal mentioned is one or more of the following: Naomaohu coal, Heishan coal, long-flame coal, lignite, and Zhundong coal.
[0016] The biomass mentioned is one or more of straw, rice husks, corn cobs, and cottonseed meal.
[0017] The polymer is one or more of polyaniline, polyethylene, polyacetylene, and polypyrrole.
[0018] The coal tar pitch is one or more of high-temperature coal tar pitch, medium-temperature coal tar pitch, and low-temperature coal tar pitch.
[0019] The metal-organic framework is one or more of ZIF-8, ZIF-90, and MOF-67.
[0020] Vermiculite was selected as the functionalizing agent in the preparation of the supercapacitor electrode material:
[0021] Vermiculite is a natural layered silicate mineral with lightweight, porous, and high-temperature resistant properties. In particular, it can isolate oxygen and is widely used as a fireproof material in the fields of construction and chemical industry. The mechanism of vermiculite's action lies mainly in its layered structure, which can effectively isolate oxygen at high temperatures, thus exhibiting good high-temperature resistance.
[0022] Compared with the prior art, the beneficial effects of the present invention are:
[0023] 1. The method of the present invention eliminates the need for carbon precursors to be protected in an inert atmosphere, enabling carbonization in an air atmosphere rather than under traditional inert gas protection, which significantly reduces equipment requirements, energy consumption and preparation costs.
[0024] 2. The method of this invention realizes the multifunctional synergistic effect of vermiculite; by utilizing vermiculite, three functionalization functions are simultaneously achieved: preventing complete combustion of carbon precursors, template, and activation, thus realizing the successful preparation of porous carbon in an air atmosphere and simplifying the process flow.
[0025] 3. The method of the present invention optimizes the pore structure and surface properties of the material: In an air atmosphere, oxygen in the air etches and activates the carbon skeleton, further enriching the pore structure of porous carbon; at the same time, a large number of oxygen-containing functional groups are introduced in situ, thereby greatly improving the surface chemical composition of porous carbon materials.
[0026] The prepared porous carbon material has abundant pores and functional groups, exhibiting excellent electrochemical performance and significantly improving the rate performance of supercapacitors.
[0027] 4. Vermiculite effectively inhibits the mass loss of carbon precursors at high temperatures, thereby achieving a higher carbon yield and improving raw material utilization and preparation economy.
[0028] 5. The method of this invention omits the complex inert gas protection system and uses natural and inexpensive vermiculite as an auxiliary agent to prepare porous carbon by carbonizing various carbon precursors in an air environment. The overall process is simple, fast, more economical and environmentally friendly. Attached Figure Description
[0029] Figure 1 This is a SEM image of the supercapacitor electrode material prepared in Example 1.
[0030] Figure 2 This is a SEM image of the supercapacitor electrode material prepared in Example 2.
[0031] Figure 3 This is a SEM image of the supercapacitor electrode material prepared in Example 3.
[0032] Figure 4 This is a SEM image of the supercapacitor electrode material prepared in Example 4.
[0033] Figure 5 This is a SEM image of the supercapacitor electrode material prepared in Example 5.
[0034] Figure 6 These are the Raman spectra of Examples 1-5.
[0035] Figure 7 These are the X-ray diffraction patterns of Examples 1-5.
[0036] Figure 8 The nitrogen adsorption / desorption curves of the porous carbon obtained in Example 1 are shown.
[0037] Figure 9 These are the GCD curves of Examples 1-5 at 0.5 A / g. Detailed Implementation
[0038] To further understand the present invention, the present invention will be described below with reference to embodiments. These descriptions are only for further explaining the features and advantages of the present invention and are not limited to the following embodiments.
[0039] Example 1:
[0040] Supercapacitor electrode materials were prepared using Naomaohu coal as a carbon precursor and vermiculite as a functionalizing agent. The preparation process is as follows:
[0041] Weigh 0.25g of Naomao Lake coal and 0.75g of vermiculite (golden yellow vermiculite, silvery white vermiculite, or milky white vermiculite), mix them thoroughly in 2mL of distilled water, and dry them in an oven at 80℃. Place the mixture in a crucible and carbonize it at 700℃ in a muffle furnace under air atmosphere at a heating rate of 5℃ / min for 1 hour. After naturally cooling to room temperature, remove the mixture, wash away the vermiculite and impurities with 10mL of 40wt% hydrofluoric acid, wash with water until neutral, and then dry it in an oven at 80℃ to obtain the final product. The final carbon yield was 24%.
[0042] See Figure 1 SEM results show that the prepared coal-based porous carbon material has a large number of pores, which is beneficial for charge storage and transport. Figure 6 As shown, its XRD pattern exhibits broad diffraction peaks near 23° and 43°, indicating the presence of an amorphous carbon structure with certain defects. Figure 7 . Figure 8 The nitrogen adsorption / desorption curves of the coal-based porous carbon material obtained in Example 1 show that the curves conform to type I and type IV isotherms, indicating the presence of abundant micropores and mesopores, with a specific surface area of 667.69 m². 2 / g, pore volume is 0.42cm³ 3 / g. For example... Figure 9As shown, the obtained porous carbon material was used as an electrode material for a supercapacitor in a three-electrode system. In a 6M KOH electrolyte, the GCD curve of the porous carbon material was an approximately symmetrical isosceles triangle, indicating that the material has good electrochemical reversibility and a specific capacitance of 286 F / g at a current density of 0.5 A / g.
[0043] Example 2:
[0044] Supercapacitor electrode materials were prepared using cotton stalks as a carbon precursor and vermiculite as a functionalizing agent. The preparation process is as follows:
[0045] Weigh 0.25 g of cotton stalk powder and 0.95 g of vermiculite (golden yellow vermiculite, silvery white vermiculite, or milky white vermiculite), mix them thoroughly in 2 mL of distilled water, and then perform high-temperature carbonization in an 80°C oven. Place the mixture in a corundum crucible, put it in a muffle furnace, and perform high-temperature carbonization at a heating rate of 5°C / min under air atmosphere, holding at 700°C for 1 hour. After cooling to room temperature, remove the product. Wash away the vermiculite and impurities with 20 mL of 40 wt% hydrofluoric acid, wash with water until neutral, and then dry in an 80°C oven to obtain the final product. The final carbon yield was 14%.
[0046] from Figure 2 The SEM images show that the porous surface prepared from cotton stalks as a carbon precursor has a large number of pores. For example... Figure 6 As shown, its XRD pattern exhibits broad diffraction peaks near 23° and 43°, indicating the presence of an amorphous carbon structure with certain defects. Figure 7 .like Figure 9 As shown, it was tested as a supercapacitor electrode material in a three-electrode system. In a 6M KOH electrolyte, the specific capacitance was 204 F / g at a current density of 0.5 A / g.
[0047] Example 3:
[0048] Supercapacitor electrode materials were prepared using polyaniline as a carbon precursor and vermiculite as a functionalizing agent. The preparation process is as follows:
[0049] Weigh 0.25 g of polyaniline and 0.85 g of vermiculite (golden yellow vermiculite, silvery white vermiculite, or milky white vermiculite), mix them thoroughly in 2 mL of distilled water, and dry them in an oven at 80 °C. Place the mixture in a corundum crucible, put it in a muffle furnace, and perform high-temperature carbonization at 700 °C under air atmosphere at a heating rate of 5 °C / min for 1 hour. After cooling to room temperature, remove the mixture. Wash away the vermiculite and impurities with 30 mL of 40 wt% hydrofluoric acid, wash with water until neutral, and then dry in an oven at 80 °C to obtain the final product. The final carbon yield is 40%.
[0050] See Figure 3SEM results show that the porous carbon material prepared using polyaniline as a carbon precursor has an irregular granular structure. For example... Figure 6 As shown, its XRD pattern exhibits broad diffraction peaks near 23° and 43°, indicating the presence of an amorphous carbon structure with certain defects. Figure 7 .like Figure 9 As shown, it was tested as a supercapacitor electrode material in a three-electrode system. In a 6M KOH electrolyte, the specific capacitance was 238 F / g at a current density of 0.5 A / g.
[0051] Example 4:
[0052] Coal tar pitch was used as a carbon precursor and vermiculite as a functionalizing agent.
[0053] Weigh 0.25g of coal tar pitch and 1.0g of vermiculite (golden yellow vermiculite, silvery white vermiculite, or milky white vermiculite), mix thoroughly in 2mL of distilled water, and dry in an oven at 80℃. Place the mixture in a corundum crucible, put it in a muffle furnace, and perform high-temperature carbonization at 700℃ in air at a heating rate of 5℃ / min for 1 hour. After cooling to room temperature, remove the mixture. Wash away the vermiculite and impurities with 20mL of 50wt% hydrofluoric acid, wash with water until neutral, and then dry in an oven at 80℃ to obtain the final product. The final carbon yield is 69%.
[0054] Scanning electron microscope (SEM) images of the prepared coal tar pitch-based porous carbon materials are shown below. Figure 4 As shown in the figure, porous carbon materials have a porous, sheet-like structure, which effectively promotes charge storage and transport. Figure 6 As shown, its XRD pattern exhibits broad diffraction peaks near 23° and 43°, indicating the presence of an amorphous carbon structure with certain defects. Figure 7 .like Figure 9 As shown, it was tested as a supercapacitor electrode material in a three-electrode system. In a 6M KOH electrolyte, the specific capacitance was 239 F / g at a current density of 0.5 A / g.
[0055] Example 5:
[0056] Supercapacitor electrode materials were prepared using ZIF-8 as a carbon precursor and vermiculite as a functionalizing agent. The preparation process is as follows:
[0057] Weigh 0.25 g of ZIF-8 and 1.25 g of vermiculite (golden yellow vermiculite, silvery white vermiculite, or milky white vermiculite), mix thoroughly in 2 mL of distilled water, and dry in an oven at 80 °C. Place the mixture in a corundum crucible, put it in a muffle furnace, and perform high-temperature carbonization at 700 °C under air atmosphere at a heating rate of 5 °C / min for 1 hour. After cooling to room temperature, remove the mixture. Wash away the vermiculite and impurities with 30 mL of 60 wt% hydrofluoric acid, wash with water until neutral, and then dry in an oven at 80 °C to obtain the final product. The final carbon yield was 23%.
[0058] See Figure 5 SEM results show that the porous carbon material prepared using ZIF-8 as the carbon precursor has a regular geometric structure. For example... Figure 6 As shown, its XRD pattern exhibits broad diffraction peaks near 23° and 43°, indicating the presence of an amorphous carbon structure with certain defects. Figure 7 .like Figure 9 As shown, when used as an electrode material for a supercapacitor, it was tested in a three-electrode system. In a 6M KOH electrolyte, the specific capacitance was 194 F / g at a current density of 0.5 A / g.
[0059] This invention utilizes vermiculite-assisted air carbonization to prepare supercapacitor electrode materials. Different carbon precursors are physically mixed with vermiculite in distilled water, followed by carbonization. The evaporation of water bound to the interlayer of vermiculite dilutes the combustible gas, and the oxides coat the surface of the carbon precursors, protecting them from complete oxidation. Furthermore, the metal oxide components in the vermiculite catalyze aromatization and cross-linking reactions of carbon macromolecules during pyrolysis, which helps form a more stable carbon framework structure and improves the yield of carbon materials. The resulting supercapacitor electrode material exhibits a specific capacitance of 192~290 F / g at a current density of 0.5 A / g.
Claims
1. A method for preparing supercapacitor electrode materials based on vermiculite-assisted air carbonization, characterized in that, Includes the following steps: 1) Take carbon precursor and vermiculite, mix them evenly in distilled water, then put them in a crucible and dry them in an oven; 2) Place the crucible in a muffle furnace and heat it to 600-1000℃ at a heating rate of 1-10℃ / min, so that it is carbonized at high temperature in air atmosphere, hold it at the temperature for 0.5-1.5h, and then let it cool naturally to room temperature. 3) Remove the crucible, wash away vermiculite and impurities with hydrofluoric acid, wash with water until neutral, and put the obtained sample into an oven to dry.
2. The method for preparing supercapacitor electrode materials based on vermiculite-assisted air carbonization according to claim 1, characterized in that, The mass ratio of vermiculite to carbon precursor is (3~10):
1.
3. The method for preparing supercapacitor electrode materials based on vermiculite-assisted air carbonization according to claim 1, wherein the drying in step 1) is to dry in an oven at 80~100℃ until the distilled water is completely evaporated.
4. The method for preparing supercapacitor electrode materials based on vermiculite-assisted air carbonization according to claim 1, wherein the vermiculite is one or more of golden vermiculite, silver-white vermiculite, and milky-white vermiculite.
5. The method for preparing supercapacitor electrode materials based on vermiculite-assisted air carbonization according to claim 1, characterized in that, The carbon precursor is one or more of coal, biomass, polymer, coal tar pitch, and metal-organic frameworks.
6. The method for preparing supercapacitor electrode materials based on vermiculite-assisted air carbonization according to claim 5, characterized in that, The coal mentioned is one or more of the following: Naomaohu coal, Heishan coal, long-flame coal, lignite, and Zhundong coal.
7. The method for preparing supercapacitor electrode materials based on vermiculite-assisted air carbonization according to claim 5, characterized in that, The biomass mentioned is one or more of straw, rice husks, corn cobs, and cottonseed meal.
8. The method for preparing supercapacitor electrode materials based on vermiculite-assisted air carbonization according to claim 5, characterized in that, The polymer is one or more of polyaniline, polyethylene, polyacetylene, and polypyrrole.
9. The method for preparing supercapacitor electrode materials based on vermiculite-assisted air carbonization according to claim 5, characterized in that, The coal tar pitch is one or more of high-temperature coal tar pitch, medium-temperature coal tar pitch, and low-temperature coal tar pitch.
10. The method for preparing supercapacitor electrode materials based on vermiculite-assisted air carbonization according to claim 5, characterized in that, The metal-organic framework is one or more of ZIF-8, ZIF-90, and MOF-67.