Sesame stalk derived carbon material as well as preparation method and application thereof
By preparing high-purity sesame straw-derived carbon materials, the problem of poor performance of supercapacitor electrode materials was solved, and zinc ion capacitors with high energy density and good electrochemical properties were achieved.
Patent Information
- Application Number
- CN202510789056.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-13
- Publication Date
- 2025-09-05
AI Technical Summary
Existing supercapacitor electrode materials have low specific surface area utilization and a narrow electrolyte decomposition voltage window. The ion transport kinetics of traditional activated carbon-based electrodes deteriorate at extreme temperatures, and impurities in biomass-derived carbon materials affect the electrochemical performance.
Sesame stalks were used as raw materials to prepare high-purity sesame stalk-derived carbon materials for electric double-layer capacitors through the steps of cleaning, ball milling, hydrothermal treatment, phosphorus doping, alkaline activation and acid washing.
The purity and electrochemical properties of biomass-derived carbon materials were improved, and the energy density of zinc ion capacitors reached 22.5Wh/kg at a power density of 5000W/kg, showing excellent electrochemical performance.
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Figure CN120600547A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of precious metal nanocatalytic materials, and in particular relates to a sesame stalk-derived carbon material and a preparation method and application thereof. Background Art
[0002] As the global energy structure transforms towards a green, clean and sustainable direction, the development of efficient energy storage and energy conversion devices has become a core issue in solving the energy crisis and achieving carbon neutrality. Supercapacitors, with their high power density, long-cycle stability and fast charging and discharging capabilities, have demonstrated unique advantages in the start-stop systems of new energy vehicles, peak regulation of smart grids and wearable electronics. However, the energy density of existing double-layer capacitors is still significantly behind that of lithium-ion batteries, which is mainly limited by bottlenecks such as low specific surface area utilization of electrode materials and narrow electrolyte decomposition voltage window. Especially under extreme temperature conditions, the deterioration of ion transport kinetics of traditional activated carbon-based electrodes can lead to severe capacity decay rate. Current research focuses on the development of new materials such as transition metal oxides and MXene, but they generally have problems such as complex preparation process, high volume expansion rate or cost-effectiveness imbalance.
[0003] Carbon-based materials are widely used in the construction of electrodes for electric double-layer capacitors due to their high specific surface area, excellent conductivity, and chemical stability. However, their raw materials mostly rely on petroleum derivatives (such as phenolic resins), which have limitations such as high cost and heavy environmental burden. In recent years, biomass-derived carbon materials prepared from crop waste (such as rice husks, straw, and fruit shells) have become an ideal choice for sustainable carbon materials due to their resource renewability, low cost, and natural porous structure. It is worth noting that biomass-derived carbon retains alkaline earth metal ions such as calcium and magnesium inherent in the raw materials during pyrolysis. Although these ions can catalyze the formation of a hierarchical porous structure, they will significantly reduce the electrochemical performance of the material. Therefore, developing green and efficient biomass-derived carbon material preparation technologies and improving the purity and energy storage performance of biomass carbon materials are of great significance to promoting the high-value utilization of agricultural waste and the development of next-generation supercapacitors. Summary of the Invention
[0004] The present invention aims to provide a sesame stalk-derived carbon material and a preparation method thereof, so as to solve the problems of poor performance and high impurities in existing supercapacitor electrode materials.
[0005] To achieve the above objectives, the present invention provides the following technical solutions:
[0006] In a first aspect, the present invention provides a method for preparing a sesame straw-derived carbon material, comprising the following steps:
[0007] Step S1, cleaning and removing impurities from sesame stalks, and ball-milling to obtain sesame stalk powder;
[0008] Step S2, performing hydrothermal treatment on the sesame stalk powder to soften the sesame stalk powder;
[0009] Step S3, soaking the softened sesame stalk powder in an alkaline solution to remove grease, and drying to obtain the degreased sesame stalk powder;
[0010] Step S4, mixing the sesame stalk powder from which oil has been removed with a phosphorus-containing compound, and subjecting the mixture to a phosphating reaction under a nitrogen or inert gas atmosphere to obtain a phosphorus-doped precursor;
[0011] Step S5, mixing the phosphorus-doped precursor with an alkaline activator, and calcining the mixture at a high temperature under a nitrogen or inert gas atmosphere to obtain a carbon material;
[0012] Step S6, acid-washing the carbon material obtained in step S5, then washing with water until neutral, and drying to obtain a sesame stalk-derived carbon material.
[0013] In some embodiments, in step S1, the cleaning and impurity removal comprises ultrasonic cleaning using deionized water.
[0014] In some embodiments, step S1 further includes drying after cleaning and removing impurities, wherein the drying includes drying at 100-150° C. for 20-40 hours.
[0015] In some embodiments, in step S2, the hydrothermal treatment temperature is 150-200°C, and the holding time is 0.5-2 hours.
[0016] In some embodiments, in step S3, the concentration of the alkaline solution is 2 to 4 mol / L, and the alkali is any one or more of potassium hydroxide, sodium hydroxide, and sodium carbonate.
[0017] In some embodiments, in step S3, the soaking treatment time is 6 to 24 hours.
[0018] In some embodiments, in step S4, the mass ratio of sesame straw powder to phosphorus-containing compound is 1:1 to 1:4, the phosphating temperature is 200 to 400° C., and the time is 2 to 5 hours.
[0019] In some embodiments, in step S4, the phosphorus-containing compound is ammonium dihydrogen phosphate.
[0020] In some embodiments, in step S5, the mass ratio of the phosphorus-doped precursor to potassium hydroxide is 1:1 to 1:10, the calcination temperature is 700 to 1000° C., and the calcination time is 2 to 8 hours.
[0021] In some embodiments, the alkaline activator is selected from potassium hydroxide, sodium hydroxide, sodium carbonate, or calcium hydroxide.
[0022] In some embodiments, in steps S4 and S5, the inert gas is argon.
[0023] In some embodiments, in step S6, the pickling is performed using a hydrochloric acid solution, the concentration of the hydrochloric acid is 0.5 to 2 mol / L, and the pickling time is 10 to 18 hours.
[0024] In some embodiments, in step S6, the drying comprises performing the drying at 60-80°C.
[0025] In a second aspect, the present invention provides a sesame straw-derived carbon material prepared by the preparation method described herein.
[0026] In a third aspect, the present invention provides use of the sesame straw derived carbon material as described herein in an electric double layer capacitor.
[0027] In some embodiments, the electric double layer capacitor is a zinc ion capacitor.
[0028] Advantageous Effects of the Invention
[0029] Compared to existing technologies, this invention offers the following advantages and benefits: The biomass-derived carbon raw material is derived from agricultural waste, offering advantages such as widespread availability, a simple process, and low cost, providing a new approach to waste recycling. Furthermore, the biomass-derived carbon produced by this invention has practical applications. Zinc ion capacitors assembled using this biomass-derived carbon exhibit excellent electrochemical performance and a high energy density of 22.5 Wh / kg at a power density of 5000 W / kg. BRIEF DESCRIPTION OF THE DRAWINGS
[0030] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.
[0031] Figure 1 The present invention is a flow chart of the method for preparing the biomass-derived carbon material.
[0032] Figure 2 is the XRD pattern of the biomass-derived carbon material prepared in Example 1.
[0033] Figure 3 is a SEM image of the biomass-derived carbon material prepared in Example 1.
[0034] Figure 4is a SEM image of the biomass-derived carbon material prepared in Example 6.
[0035] Figure 5 is the XRD pattern of the biomass-derived carbon material prepared in Example 9.
[0036] Figure 6 This is a constant current charge and discharge diagram of the biomass-derived carbon material prepared in Example 1.
[0037] Figure 7 is a graph of the specific capacity of the biomass-derived carbon material prepared in Example 1. DETAILED DESCRIPTION
[0038] To make the purpose, technical solutions and advantages of the present invention more clear, the technical solutions of the present invention will be described in detail below. Obviously, the embodiments described are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.
[0039] In a specific embodiment, reference Figure 1 As shown, the present invention provides a method for preparing a sesame straw-derived carbon material, which comprises the following steps:
[0040] In step S1, the sesame stalks are pre-treated with deionized water, such as ultrasonic cleaning and drying, to remove impurities such as dust on the surface, and then ball-milled to obtain sesame stalk powder. The drying in this step is performed in an oven at a drying temperature of 100 to 150° C.
[0041] Step S2: dispersing the product obtained in step S1 in deionized water and placing the product in a reactor for hydrothermal treatment at a temperature of 150 to 200° C. for a holding time of 0.5 to 2 hours.
[0042] Step S3, dispersing the product obtained in step S2 in an alkaline solution with a concentration of 2 to 4 mol / L, wherein the alkaline solution is any one or more of potassium hydroxide, sodium hydroxide and sodium carbonate.
[0043] Step S4: mixing the product obtained in step S3 with ammonium dihydrogen phosphate and placing the mixture in a tube furnace under an argon atmosphere at a temperature of 200-400° C. for 2-5 hours.
[0044] Step S5: Mix the product obtained in step S4 with potassium hydroxide and place the mixture in a tube furnace under an argon atmosphere and heat to 700-1000° C. for 2-8 hours.
[0045] Step S6, pouring the product obtained in step S5 into a hydrochloric acid solution and stirring, and then washing with deionized water until neutral, wherein in this step, the concentration of the hydrochloric acid solution is 0.5-2 mol / L, and the pickling time is 24-48 hours.
[0046] In a specific embodiment, the present invention provides use of the sesame straw-derived carbon material as described herein in a zinc ion capacitor.
[0047] As an example, the application involves mixing sesame straw-derived carbon material (80 wt%), conductive carbon black (15 wt%), and hydroxymethyl cellulose (5 wt%) with a small amount of deionized water to form a slurry. The slurry is then coated onto a graphite carbon sheet (1.0 cm x 1.0 cm) of uniform thickness and dried at 60°C for 12 hours to produce a working electrode. 2 mol / L ZnSO₄ is used as the electrolyte, and a zinc sheet and Hg / HgO standard electrode serve as the counter and reference electrodes, respectively.
[0048] The present invention is further described below with reference to specific examples, which, however, are not intended to limit the present invention in any way. Unless otherwise specified, the reagents, methods, and equipment used in the present invention are conventional reagents, methods, and equipment in the art.
[0049] Example 1:
[0050] This embodiment provides a method for preparing a sesame stalk-derived carbon material, comprising the following steps:
[0051] Step S1, ultrasonically cleaning the recovered sesame stalks with deionized water, drying them in an oven at 100° C., and ball-milling them to obtain sesame stalk powder.
[0052] Step S2: Disperse the product obtained in step S1 in deionized water and place it in a reactor, and perform hydrothermal treatment at 180° C. in an oven for 1 hour.
[0053] Step S3: soak the product obtained in step S2 in a 2 mol / L potassium hydroxide solution for 10 hours, and dry the obtained product in a forced air drying oven at 80 degrees Celsius for 24 hours.
[0054] Step S4: Mix the product obtained in step S3 with twice the mass of ammonium dihydrogen phosphate and place the mixture in a tube furnace and heat to 350° C. under an argon atmosphere for 2 hours.
[0055] Step S5: Mix the product obtained in step S4 with 8 times the mass of potassium hydroxide and place the mixture in a tube furnace, heating it to 800° C. under an argon atmosphere and treating for 2 hours.
[0056] Step S6, pouring the product obtained in step S5 into a 2 mol / L hydrochloric acid solution and stirring for 24 hours, then washing with deionized water until neutral, and drying in an oven at 80° C. to obtain a sesame straw-derived carbon material.
[0057] The sesame straw derived carbon material obtained in this example was characterized structurally. Figure 2 and 3 As shown, Figure 2 The XRD pattern of the sesame straw-derived carbon material obtained in this example is shown. Figure 3 The scanning electron micrograph of the sesame straw-derived carbon material obtained in this example is shown, which indicates that the carbon material was obtained and the sample contained no impurities.
[0058] Example 2
[0059] The difference from Example 1 is that 10 times the mass of potassium hydroxide is used in step S5.
[0060] Example 3
[0061] The difference from Example 1 is that 6 times the mass of potassium hydroxide is used in step S5.
[0062] Example 4
[0063] The difference from Example 1 is that 4 times the mass of potassium hydroxide is used in step S5.
[0064] Example 5
[0065] The difference from Example 1 is that double the mass of potassium hydroxide is used in step S5.
[0066] Example 6
[0067] The difference from Example 1 is that 1 times the mass of potassium hydroxide is used in step S5.
[0068] The scanning electron microscope image of the sesame straw derived carbon material obtained in Example 6 is as follows: Figure 4 As shown, it can be seen that the obtained carbon material is agglomerated and has a low porosity.
[0069] Example 7
[0070] The difference from Example 1 is that ammonium dihydrogen phosphate is not added in step S4, and the product obtained in step S3 is directly placed in a tube furnace and heated to 350° C. under an argon atmosphere for 2 hours.
[0071] Example 8
[0072] The difference from Example 1 is that in step S4, the product obtained in step S3 is mixed with 4 times the mass of ammonium dihydrogen phosphate and placed in a tube furnace and heated to 350° C. under an argon atmosphere for 2 hours.
[0073] Example 9
[0074] The difference from Example 1 is that deionized water is used instead of hydrochloric acid in step S6.
[0075] The XRD pattern of the sesame straw derived carbon material obtained in Example 9 is as follows: Figure 5 As shown, it can be seen that the sample contains metal impurities.
[0076] Application Examples
[0077] The sesame straw-derived carbon material prepared in Example 1 was used to assemble a zinc ion capacitor: Sesame straw-derived carbon material (80 wt%), conductive carbon black (15 wt%), and hydroxymethyl cellulose (5 wt%) were mixed with a small amount of deionized water and ground into a slurry. The slurry was then coated onto a graphite carbon sheet (1.0 cm × 1.0 cm) of uniform thickness and dried at 60°C for 12 h to obtain a working electrode. 2 mol / L ZnSO₄ was used as the electrolyte, and the zinc sheet and Hg / HgO standard electrode served as the counter and reference electrodes, respectively.
[0078] The capacitance performance of the prepared zinc ion capacitor was tested, and the results were as follows: Figure 6 As shown in Figure 7, it can be seen that the sesame straw-derived carbon material prepared by the present invention has excellent capacitor performance. When the mass ratio of the phosphorus-doped precursor to potassium hydroxide is 1:8, the obtained sesame straw-derived carbon material exhibits the best performance. Constant current charge and discharge curve ( Figure 6 ) shows good symmetry, indicating that the material has good reversibility and Coulombic efficiency. Figure 7 The specific capacity graph in Table 1 shows that the sample has a discharge capacity of 115.54 mAh / g at 0.2 A / g. Even at 10 A / g, the discharge capacity remains at 29.78 mAh / g. Furthermore, Examples 1 to 6 in Table 1 show that the amount of potassium hydroxide added has an impact on sample performance; Examples 1, 7, and 8 in Table 1 show that the amount of ammonium dihydrogen phosphate added has a more significant impact on sample performance.
[0079]
[0080]
[0081] It should be noted that the preferred embodiments of the present invention are given in the specification and drawings of the present invention. However, the present invention can be implemented in many different forms and is not limited to the embodiments described in this specification. These embodiments are not intended to be additional limitations on the content of the present invention. The purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive. In addition, the above-mentioned technical features can be combined with each other to form various embodiments not listed above, which are all considered to be within the scope of the description of the present invention. Furthermore, it is obvious to those skilled in the art that improvements or changes can be made based on the above description, and all such improvements and changes should fall within the scope of protection of the claims attached to the present invention.
Claims
1. A method for preparing a sesame straw-derived carbon material, characterized in that: The following steps are involved: Step S1, cleaning and removing impurities from sesame stalks, and ball-milling to obtain sesame stalk powder; Step S2, performing hydrothermal treatment on the sesame stalk powder to soften the sesame stalk powder; Step S3, soaking the softened sesame stalk powder in an alkaline solution to remove grease, and drying to obtain the degreased sesame stalk powder; Step S4, mixing the sesame stalk powder from which oil has been removed with a phosphorus-containing compound, and subjecting the mixture to a phosphating reaction under a nitrogen or inert gas atmosphere to obtain a phosphorus-doped precursor; Step S5, mixing the phosphorus-doped precursor with an alkaline activator, and calcining the mixture at a high temperature under a nitrogen or inert gas atmosphere to obtain a carbon material; Step S6, acid-washing the carbon material obtained in step S5, then washing with water until neutral, and drying to obtain a sesame stalk-derived carbon material.
2. The preparation method according to claim 1, characterized in that In step S1, the cleaning and impurity removal includes ultrasonic cleaning using deionized water; In step S1, a drying process is further included after cleaning and removing impurities, wherein the drying process includes drying at 100-150° C. for 20-40 hours.
3. The preparation method according to claim 1, characterized in that In step S2, the hydrothermal treatment temperature is 150-200°C, and the holding time is 0.5-2h.
4. The preparation method according to claim 1, characterized in that In step S3, the concentration of the alkaline solution is 2 to 4 mol / L, and the alkali is any one or more of potassium hydroxide, sodium hydroxide, and sodium carbonate; The soaking treatment time is 6 to 24 hours.
5. The preparation method according to claim 1, characterized in that In step S4, the mass ratio of sesame stalk powder to phosphorus-containing compound is 1:1 to 1:4, the phosphating temperature is 200 to 400° C., and the time is 2 to 5 hours; The phosphorus-containing compound is ammonium dihydrogen phosphate.
6. The preparation method according to claim 1, characterized in that In step S5, the mass ratio of the phosphorus-doped precursor to the alkaline activator is 1:1 to 1:10, the calcination temperature is 700 to 1000° C., and the calcination time is 2 to 8 hours; The alkaline activator is selected from potassium hydroxide, sodium hydroxide, sodium carbonate or calcium hydroxide.
7. The preparation method according to claim 1, characterized in that In step S6, the pickling is performed using a hydrochloric acid solution with a concentration of 0.5 to 2 mol / L and a pickling time of 10 to 18 hours.
8. A sesame straw-derived carbon material prepared by the preparation method according to any one of claims 1 to 7.
9. Use of the sesame straw derived carbon material as claimed in claim 8 in an electric double layer capacitor.
10. The use according to claim 9, characterized in that The electric double layer capacitor is a zinc ion capacitor.