Preparation method of nitrogen-doped cane molasses-based carbon material and application of nitrogen-doped cane molasses-based carbon material in supercapacitor
By preparing nitrogen-doped sugarcane molasses-based carbon materials, the problems of high cost and low specific capacity of carbon-based supercapacitor materials are solved, and the effects of simplifying processes, reducing costs and improving electrochemical performance are achieved.
Patent Information
- Application Number
- CN202510428144.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-07
- Publication Date
- 2025-07-25
AI Technical Summary
The existing carbon-based supercapacitor electrode materials have high cost, complex preparation processes, and low specific capacity of biomass materials, which limits their application in supercapacitors.
By activate the sugarcane molasses and carbonize the sugarcane molasses, nitrogen-doped sugarcane molasses-based carbon materials are prepared, applied to supercapacitor electrodes, increasing surface groups and active sites, and improving the wettability and specific capacitance of the material.
The preparation process is simplified, the cost is reduced, the specific surface area and capacity of the material are improved, the wettability of the electrode material and the electrolyte is enhanced, and the electrochemical performance of the supercapacitor is optimized.
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Figure CN120364697A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of new energy materials, and particularly relates to a method for preparing nitrogen-doped molasses-based carbon materials and their application in supercapacitors. Background Art
[0002] As a new type of energy storage device, supercapacitors have shown broad application prospects in the fields of new energy vehicles, smart grids, portable electronic devices, etc. due to their high power density, fast charge and discharge capabilities, and long cycle life. However, carbon-based electrode materials (such as graphene, carbon nanotubes) are restricted in their application and popularization due to their high cost and complex preparation processes. Biomass materials have potential application value in supercapacitors due to their wide sources, low cost, and environmental friendliness. However, their low specific capacitance limits their industrial application. Currently, through modification technologies (element doping, compounding, etc.), the surface groups and active sites of carbon materials can be significantly increased, and their wettability can be improved, thereby optimizing the comprehensive performance of supercapacitors. Therefore, increasing the surface groups and active sites of bio-carbon materials and improving their wettability are of great significance for improving the electrochemical performance of supercapacitors. Summary of the Invention
[0003] Aiming at the above problems, the present invention provides a method for preparing nitrogen-doped molasses-based carbon materials and their application in supercapacitors. First, molasses is activated, and finally, high-temperature carbonization is carried out to obtain nitrogen-doped molasses-based carbon materials, which are applied to supercapacitors.
[0004] The object of the present invention is achieved by the following technical solutions:
[0005] A method for preparing nitrogen-doped molasses-based carbon materials, characterized in that: 2.0 - 5.0 g of molasses, 0.2 - 0.5 g of melamine, and 1.0 - 1.5 g of potassium hydroxide (KOH) are successively added to a solvent, stirred and mixed evenly, reacted in a water bath or oil bath at 80 - 90 °C for 2 - 5 h, and then dried in an oven at 55 - 65 °C for 12 - 24 h. The solid is taken out, 3.0 - 4.0 g of KOH is added and mixed evenly, and then placed in a tubular furnace and fired at 500 - 900 °C in an inert atmosphere for 2 - 4 h. After cooling, a certain amount of 2 mol / L hydrochloric acid is added, centrifuged at 7000 rpm for 5 min, and washed alternately with deionized water and ethanol 3 - 5 times. The lower layer precipitate is collected and dried in an oven at 55 - 65 °C for 12 - 24 h to obtain nitrogen-doped molasses-based carbon materials.
[0006] Further, the solvent is deionized water.
[0007] Further, the concentration of the cane molasses in the solvent is 1 g / ml; the mass ratio of the cane molasses to KOH is 1:1; the mass ratio of the cane molasses to melamine is 10 - 25:1.
[0008] Further, the temperature of the oven is 55 - 65 °C, and the time is 12 - 24 h.
[0009] Further, the heating rate of the tubular furnace is 4 - 6 °C / min, the temperature is 500 - 900 °C, and the inert gas is nitrogen or argon.
[0010] Further, the nitrogen-doped cane molasses-based carbon material can be applied to supercapacitors. The specific application is as follows: Using the nitrogen-doped cane molasses-based carbon material as the electrode material, it is mixed with acetylene black and polytetrafluoroethylene to form a slurry. After coating the obtained slurry on the surface of nickel foam and drying it in an oven, a supercapacitor working electrode assembled from the nitrogen-doped cane molasses-based carbon material is obtained.
[0011] Compared with the prior art, the advantages and beneficial effects of the present invention are as follows:
[0012] 1. The preparation method of the present invention is simple in operation, short in cycle, and easy to industrialize. Through water bath or oil bath heating and high-temperature carbonization, a nitrogen-doped cane molasses-based carbon material is obtained. The material presents a porous structure, which greatly increases the specific surface area of the carbon material. The larger the electric double layer formed as the electrode material, the more ions can be adsorbed, thus significantly improving the capacitance.
[0013] 2. The doping of nitrogen elements further increases the surface groups and active sites, thereby affecting the wettability between the electrode material and the electrolyte and increasing the specific capacitance of the supercapacitor. And by controlling the doping amount of nitrogen elements, the electrochemical performance of the carbon material can be further adjusted. BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The present invention will be further described below in conjunction with the drawings.
[0015] Figure 1 It is a scanning electron microscope (SEM) image of the nitrogen-doped cane molasses-based carbon material with optimal performance.
[0016] Figure 2 It is a cyclic voltammetry curve (CV) image of the supercapacitor assembled from the nitrogen-doped cane molasses-based carbon material in Example 1.
[0017] Figure 3 It is a galvanostatic charge-discharge curve (GCD) image of the supercapacitor assembled from the nitrogen-doped cane molasses-based carbon material in Example 1.
[0018] Figure 4The electrochemical impedance spectroscopy (EIS) diagram of the nitrogen-doped molasses-based carbon material in Example 1 after being assembled into a supercapacitor.
[0019] Figure 5 The cyclic voltammetry curve (CV) diagram of the nitrogen-doped molasses-based carbon material in Example 2 after being assembled into a supercapacitor.
[0020] Figure 6 The galvanostatic charge-discharge curve (GCD) diagram of the nitrogen-doped molasses-based carbon material in Example 2 after being assembled into a supercapacitor.
[0021] Figure 7 The electrochemical impedance spectroscopy (EIS) diagram of the nitrogen-doped molasses-based carbon material in Example 2 after being assembled into a supercapacitor.
[0022] Figure 8 The comparative curve diagram of the specific capacitance of the supercapacitors in Examples 1 and 2 at different current densities. Detailed implementation manners
[0023] To make the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments, so as to understand the technical solutions and technical effects of the present invention. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.
[0024] Example 1
[0025] 5.0 g of molasses, 0.2 g of melamine, and 1.5 g of potassium hydroxide (KOH) were successively added to a solvent, stirred and mixed evenly, reacted in a water bath or oil bath at 85 °C for 3 h, and then placed in an oven at 60 °C for 12 h for drying. After adding 3.5 g of KOH and mixing evenly, it was calcined in a tubular furnace at 800 °C for 2 h in an inert atmosphere. After cooling, 10 ml of hydrochloric acid (2 mol / L) was added, centrifuged at 7000 rpm for 5 min, and washed alternately with deionized water and ethanol 4 times. The lower layer precipitate was collected and dried in an oven at 60 °C for 12 h to obtain the nitrogen-doped molasses-based carbon material. The obtained nitrogen-doped molasses-based carbon material, acetylene black, and polyvinylidene fluoride (PVDF) were added in a weight ratio of 8:1:1 to an appropriate amount of N-methylpyrrolidone (NMP) and mixed to form a slurry as the working electrode. After the slurry was coated on the surface of nickel foam, it was dried in an oven at 60 °C for 12 hours. Electrochemical tests were carried out using a three-electrode system (the reference electrode was a mercury oxide electrode, and the counter electrode was a platinum sheet electrode) with a CHI760E electrochemical workstation, and the cyclic voltammetry curve (CV), galvanostatic charge-discharge curve (GCD), and electrochemical impedance spectroscopy (EIS) were measured in a 6 mol / L KOH electrolyte.
[0026] Example 2
[0027] 5.0 g of cane molasses, 0.5 g of melamine, and 1.5 g of potassium hydroxide (KOH) were successively added to the solvent, stirred and mixed evenly, reacted in a water bath or oil bath at 85 °C for 3 h, and then dried in an oven at 60 °C for 12 h. After adding 3.5 g of KOH and mixing evenly, it was calcined in a tube furnace at 800 °C in an inert atmosphere for 2 h. After cooling, 10 ml of hydrochloric acid (2 mol / L) was added, centrifuged at 7000 rpm for 5 min, and washed alternately with deionized water and ethanol 4 times. The lower-layer precipitate was collected and dried in an oven at 60 °C for 12 h. A nitrogen-doped cane molasses-based carbon material was obtained. The obtained nitrogen-doped cane molasses-based carbon material, acetylene black, and polyvinylidene fluoride (PVDF) were added in a weight ratio of 8:1:1 to an appropriate amount of N-methylpyrrolidone (NMP) and mixed into a slurry as the working electrode. After the slurry was coated on the surface of nickel foam, it was dried in an oven at 60 °C for 12 h. Electrochemical tests were carried out using a three-electrode system (the reference electrode was a mercury oxide electrode, and the counter electrode was a platinum sheet electrode) with a CHI760E electrochemical workstation to measure cyclic voltammetry curves (CV), galvanostatic charge-discharge curves (GCD), and electrochemical impedance spectra (EIS) in a 6 mol / L KOH electrolyte.
[0028] The test results show that:
[0029] Figure 1 This is the SEM of the nitrogen-doped cane molasses-based carbon material with the best performance. It shows a porous morphology with pore structures of different sizes, and there may be connectivity between the pores. This porous structure is formed by the decomposition and volatilization of organic components at high temperatures and is crucial for the transport of liquids or ions inside the material.
[0030] The prepared nitrogen-doped cane molasses-based carbon material was tested by cyclic voltammetry, and the results are as Figure 2 and Figure 5 shown. At different scanning rates, the cyclic voltammetry curves are in the shape of a quasi-rectangle, indicating good electric double-layer capacitance performance.
[0031] The prepared nitrogen-doped cane molasses-based carbon material was tested by charge-discharge, and the results are as Figure 3 and Figure 6 shown. Its charge-discharge curves have good symmetry, indicating good electric double-layer capacitance performance. Figure 8 This is a comparative graph of the specific capacitances of the supercapacitors in Examples 1 and 2 of at different current densities. When the addition amount of melamine is 0.2 g, the specific capacitance is 366.9 F / g at a current density of 1 A / g; when the addition amount of melamine is 0.5 g, the specific capacitance is 151.7 F / g at a current density of 1 A / g. It can be seen that the nitrogen-doped cane molasses-based carbon material with an addition amount of 0.2 g of melamine has better electrochemical performance.
[0032] The electrochemical impedance spectroscopy of the prepared nitrogen-doped sugarcane molasses-based carbon material was tested. Figure 4 and Figure 7 As shown in the figure, the obtained Nyquist diagram is semicircular in the high-frequency region, and the radius of the semicircle in the high-frequency region is very small, reflecting that R ct Very small, at low frequencies, the oblique line shows the capacitance characteristics.
Claims
1. A preparation method of a nitrogen-doped molasses-based carbon material, characterized in that: Add cane molasses, melamine, and potassium hydroxide (KOH) to the solvent in sequence, stir and mix evenly, react in a water bath or oil bath at 80 - 90 °C for 2 - 5 h, then dry in an oven at 55 - 65 °C for 12 - 24 h; take out the solid, add 3.0 - 4.0 g of KOH and mix evenly, then place it in a tubular furnace and calcine in an inert atmosphere at 500 - 900 °C for 2 - 4 h; after cooling, add a certain amount of 2 mol / L hydrochloric acid, centrifuge at 7000 rpm for 5 min, and wash alternately with deionized water and ethanol 3 - 5 times, collect the lower precipitate and dry in an oven at 55 - 65 °C for 12 - 24 h to obtain the nitrogen-doped cane molasses-based carbon material.
2. The preparation method according to claim 1, wherein The solvent is deionized water.
3. The preparation method according to claim 1, characterized in that The concentration of cane molasses in the solvent is 1 g / ml; the mass ratio of cane molasses to KOH is 1:1; the mass ratio of cane molasses to melamine is 10 - 25:
1.
4. The preparation method according to claim 1, wherein The oven temperature is 55 - 65 °C and the time is 12 - 24 h.
5. The preparation method according to claim 1, wherein The heating rate of the tubular furnace is 4 - 6 °C / min, the temperature is 500 - 900 °C, and the inert gas is nitrogen or argon.
6. Use of the nitrogen-doped molasses-based carbon material according to claims 1-5, characterized in that: Using the nitrogen-doped cane molasses-based carbon material as the electrode material, mix it with acetylene black and polytetrafluoroethylene in proportion to make a slurry, coat the obtained slurry on the surface of nickel foam, and dry in an oven at 55 - 65 °C for 13 - 17 hours to obtain the working electrode of the supercapacitor assembled with the nitrogen-doped cane molasses-based carbon material.