Biomass-based carbon negative electrode material for supercapacitor and preparation method and application of biomass-based carbon negative electrode material
By preparing bagasse-based carbon nanofiber materials, constructing a hierarchical porous structure dominated by mesopores and introducing oxygen/phosphorus-containing surface functional groups, the problem of insufficient specific capacitance and power density of traditional supercapacitor anode materials was solved, and efficient electrochemical performance was improved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-01-21
- Publication Date
- 2026-04-21
AI Technical Summary
Traditional supercapacitor anode carbon materials have limited specific capacitance, are resource-constrained, costly, and environmentally unfriendly. Commercial biomass-derived carbon materials are mainly microporous and lack mesoporous/macroporous structures, which are not conducive to ion transport, resulting in insufficient rate performance and power density.
Using sugarcane bagasse as raw material, impurities are removed through leaching treatment. Melamine and graphene oxide are combined to form a spinning solution, which is then pre-sintered and sintered at high temperature with nitrogen to form carbon nanofibers. Subsequently, the fibers are impregnated with phosphoric acid solution and activated under high temperature with nitrogen to construct a hierarchical porous structure dominated by mesopores, and oxygen/phosphorus-containing surface functional groups are introduced.
It significantly improves the transport channels and surface reactivity of electrolyte ions, enhances the interfacial interaction between the electrode and the electrolyte, and improves specific capacitance, rate performance and power density, thus achieving supercapacitor performance with high energy density and high power density.
Smart Images
Figure SMS_1
Abstract
Description
Technical Field
[0001] This invention belongs to the field of supercapacitor technology, specifically relating to a biomass-based carbon anode material for supercapacitors, its preparation method, and its application. Background Technology
[0002] Supercapacitors, as a highly promising electrochemical energy storage device, have shown broad application prospects in numerous fields such as electric vehicles, smart grids, and consumer electronics due to their significant advantages such as high power density, fast charge and discharge speeds, and long cycle life. The anode material, as a key component of supercapacitors, directly determines the overall electrochemical performance of the supercapacitor. Traditional carbon anode materials for supercapacitors, such as activated carbon and carbon nanotubes, face several problems in practical applications. First, these anode materials have limited specific capacitance, making it difficult to meet the ever-increasing demand for high-energy-density energy storage. Second, their resource availability is limited; the mining and processing of some raw materials puts significant pressure on the environment, and the relatively high cost restricts the large-scale commercial application of supercapacitors. Biomass waste is generated in large quantities globally, such as magnolia leaves, citrus peels, monk fruit leaves, sugarcane bagasse, and straw. If these biomass wastes are not properly treated, they will not only waste resources but also cause environmental pollution. Biomass-based carbon materials, with their outstanding advantages of renewability, low cost, and environmental friendliness, are gradually becoming a research hotspot for supercapacitor anode materials. Porous carbon materials prepared through the derivative processing of biomass waste possess unique structural characteristics. In particular, precise control of carbonization and activation processes (e.g., using KOH activation) can form a hierarchical porous structure encompassing micropores, mesopores, and macropores. This hierarchical structure provides abundant transport channels and storage space for electrolyte ions, facilitating rapid ion transport and storage, thereby significantly increasing the material's specific surface area and specific capacitance. Furthermore, heteroatom (such as N and S) doping techniques can further optimize the surface chemistry of biomass-based carbon materials, improving their interfacial interactions with the electrolyte and thus substantially enhancing their electrochemical performance.
[0003] However, traditional commercial biomass-derived carbon materials are mainly microporous, lacking mesoporous and macroporous structures, which limits their application in supercapacitors. Although microporous structures can provide a certain specific surface area, they are not conducive to the rapid transport of electrolyte ions, resulting in insufficient rate performance and power density. Summary of the Invention
[0004] In view of the current situation where traditional supercapacitor anode carbon materials have limited specific capacitance, limited resources, high cost and are not environmentally friendly; and that traditional commercial biomass-derived carbon materials are mainly microporous and lack mesopores / macropores, which is not conducive to ion transport and leads to insufficient rate performance and power density, this invention aims to provide a biomass-based carbon anode material for supercapacitors, its preparation method and application.
[0005] To achieve the above objectives, the present invention employs the following technical solution: This invention provides a method for preparing a biomass-based carbon anode material for supercapacitors, comprising: Step 1: After processing the sugarcane bagasse, dry, crush, extract, filter, and wash the sediment to obtain mixture 1; Step 2: Add mixture 1 and melamine to N,N-dimethylformamide, heat and stir to dissolve, then add graphene oxide and stir to obtain a spinning solution to obtain a precursor for spinning. Step 3: The precursor is pre-sintered and sintered in a nitrogen atmosphere to obtain carbon nanofibers; Step 4: After impregnating the carbon nanofibers with phosphoric acid solution, the impregnated carbon nanofibers are activated in a nitrogen atmosphere, cooled, washed, and vacuum dried to obtain a porous biomass-based carbon anode material with mesopores as the main component and rich in oxygen / phosphorus surface functional groups.
[0006] In step 1, the extraction solvent used is an aqueous ethanol solution with a volume fraction of 40-60%, and the extraction material-to-liquid ratio is 1:(10-20).
[0007] In step 2, the mass ratio of the mixture 1, melamine, N,N-dimethylformamide and graphene oxide is (1~5):(0.1~5):(0.1~2):(10~30).
[0008] In step 2, the heating and stirring temperature is 60~80℃.
[0009] In step 3, the pre-sintering temperature is 200~400℃ and the holding time is 4~6h, and the sintering temperature is 1500~1700℃ and the holding time is 2~4h.
[0010] In step 4, the mass-to-volume ratio of the carbon nanofibers to the phosphoric acid solution is 1 g: (100~200) mL.
[0011] In step 4, the activation temperature is 500~700℃ and the holding time is 1~3h; the vacuum drying temperature is 100~140℃.
[0012] This invention provides a biomass-based carbon anode material for supercapacitors obtained by the preparation method described above.
[0013] The present invention relates to the application of the above-mentioned biomass-based carbon anode material for supercapacitors in the preparation of supercapacitors.
[0014] The present invention provides a supercapacitor, wherein the supercapacitor uses the aforementioned biomass-based carbon anode material for supercapacitors.
[0015] Compared with the prior art, the present invention achieves the following technical effects: The present invention provides a method for preparing biomass-based carbon anode materials for supercapacitors, which combines the resource utilization of biomass waste with the regulation of hierarchical pore structure to construct porous carbon materials with mesopore advantages. Sugarcane bagasse was selected as the biomass raw material. Impurities such as lignin were removed through leaching, while the cellulose skeleton was retained to provide a structural basis for subsequent carbonization. Through the synergistic effect of melamine and graphene oxide, a uniformly dispersed spinning solution was formed in N,N-dimethylformamide solution. Melamine served as a nitrogen source to promote heteroatom doping, while graphene oxide enhanced the construction of the conductive network. A gradient sintering process was adopted, in which the organic matter was pyrolyzed and carbonized in the pre-sintering stage, and high-temperature nitrogen sintering promoted the formation of graphite microcrystals, resulting in carbon nanofibers with a three-dimensional continuous structure. Through phosphate solution impregnation and activation, a mesoporous structure was formed by controlled etching under a high-temperature nitrogen atmosphere. At the same time, the phosphorus-containing groups generated by phosphate decomposition combined with the carbon skeleton to form surface functional groups, enhancing the surface wettability and pseudocapacitance contribution of the material. This method, through the organic combination of biomass precursor selection, heteroatom synergistic doping, spinning control, and gradient activation treatment, constructed a multi-level porous structure dominated by mesopores and formed a carbon skeleton modified with oxygen / phosphorus functional groups, effectively improving ion transport efficiency and surface reactivity.
[0016] Furthermore, the choice of ethanol-water solution as the extraction solvent not only disrupts the biomass cell wall structure through hydrogen bonding but also avoids the irreversible damage to the biomass skeleton caused by strong acids and bases, providing a foundation for the subsequent formation of a hierarchical porous structure dominated by mesopores. By balancing the relationship between the carbon source, pore-forming agent, and dopant, the material is guaranteed to form a hierarchical pore structure dominated by mesopores while promoting the directional enrichment of oxygen- and phosphorus-containing functional groups, ultimately achieving rapid diffusion of electrolyte ions and enhanced charge storage capacity. The synergistic control of the two-stage holding time ensures sufficient carbonization reaction while avoiding excessive sintering that leads to pore closure, ultimately forming a hierarchical porous structure dominated by mesopores, providing a rapid transport channel for electrolyte ions.
[0017] The biomass-based carbon anode material for supercapacitors provided by this invention constructs a hierarchical porous structure dominated by mesopores and endows the material surface with abundant oxygen- and phosphorus-containing functional groups. Compared with traditional microporous structures, the mesopore structure can significantly increase the transport channels of electrolyte ions and improve the ion diffusion rate, thereby improving rate performance and power density. The introduction of oxygen- and phosphorus-containing functional groups can enhance the wettability of the material surface, optimize the charge transport efficiency at the electrode-electrolyte interface, and provide additional pseudocapacitance through surface redox reactions, thereby improving specific capacitance.
[0018] The application provided by this invention utilizes the mesoporous structure of biomass-based carbon materials to offer rapid ion transport channels for the electrolyte, overcoming the diffusion limitations imposed by microporous-dominated structures. Surface oxygen / phosphorus functional groups enhance charge storage capacity by improving the interfacial interaction between the material and the electrolyte. This application transforms renewable biomass resources into high-performance energy storage devices, achieving environmental friendliness while maintaining high specific capacitance. Through structure-performance synergistic optimization, it overcomes the bottlenecks in power density and rate performance of traditional carbon materials.
[0019] The supercapacitor provided by this invention uses biomass-based carbon anode material. Its hierarchical porous structure and heteroatom doping synergistic effect ultimately enable the supercapacitor to have both high energy density and high power density characteristics, and has broad application prospects. Detailed Implementation
[0020] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.
[0021] Where specific experimental steps or conditions are not specified in the embodiments, they can be performed according to the conventional experimental steps or conditions described in the literature in this field. Reagents or instruments whose manufacturers are not specified are all commercially available products. In this invention, unless otherwise specified, all experimental materials used are commercially available commodities well-known to those skilled in the art.
[0022] Example 1 This embodiment provides a biomass-based carbon anode material for supercapacitors, and the specific preparation steps are as follows: Step 1: Wash the sugarcane bagasse to remove impurities such as mud and sugar, and dry it to obtain dried sugarcane bagasse. Grind the dried sugarcane bagasse to below 200 mesh using a high-speed grinder. Transfer the ground sugarcane bagasse and a 50 v / v% ethanol / water solution to a round-bottom flask with a liquid ratio of 1:15. Heat the round-bottom flask to 70°C in a water bath and stir for 3 hours. After the reaction stops, filter using a Buchner funnel, collect the filtrate, add hydrochloric acid to the filtrate to adjust the pH to about 3, and let the solution stand for precipitation for 48 hours. Filter again using a Buchner funnel to collect the precipitate, and wash with deionized water until the washing liquid is neutral. Dry under vacuum at 45°C to obtain mixture 1.
[0023] Step 2: Add 2g of mixture 1 and 0.3g of melamine to 20g of N,N-dimethylformamide, stir at 70℃ until completely dissolved, add 0.2g of graphene oxide, and continue stirring for 48h to obtain a spinning solution. Then, put the obtained spinning solution into a spinning device (20kV, 1.0mL / h, receiving distance of 15cm) for spinning to obtain the precursor.
[0024] Step 3: Transfer the precursor to an alumina crucible and heat it to 300°C in a muffle furnace at a heating rate of 1°C / min. After holding at this temperature for 5 hours, heat-stable fibers are obtained. Under a nitrogen atmosphere, the heat-stable fibers are transferred to a tube furnace and heated to 1600°C at a heating rate of 10°C / min. After holding at this temperature for 3 hours, carbon nanofibers are obtained.
[0025] Step 4: Mix 1g of carbon nanofibers with 100mL of 5mol / L phosphoric acid solution at a specific impregnation ratio (1:1). Let the mixed solution stand at room temperature overnight for impregnation. Then, transfer the mixture to a drying device and dry it at 120℃. Subsequently, place the dried mixture in a covered crucible and activate it by heating it to 600℃ at 10℃ / min under a nitrogen atmosphere and holding it at that temperature for 2 hours. After activation, let the product cool naturally. Then, wash the cooled product repeatedly with 50℃ hot water until the filtrate is close to neutral to completely remove residual phosphoric acid. Finally, transfer the washed product to a vacuum drying oven and dry it under vacuum at 120℃. After drying, grind it to obtain a porous biomass-based carbon anode material with mesopores as the main feature and rich in oxygen / phosphorus surface functional groups.
[0026] Example 2 This embodiment provides a biomass-based carbon anode material for supercapacitors, and the specific preparation steps are as follows: Step 1: Wash the sugarcane bagasse to remove impurities such as mud and sugar, and dry it to obtain dried sugarcane bagasse. Grind the dried sugarcane bagasse to below 200 mesh using a high-speed grinder. Transfer the ground sugarcane bagasse and a 50 v / v% ethanol / water solution to a round-bottom flask with a liquid ratio of 1:15. Heat the round-bottom flask to 70°C in a water bath and stir for 3 hours. After the reaction stops, filter using a Buchner funnel, collect the filtrate, add hydrochloric acid to the filtrate to adjust the pH to about 3, and let the solution stand for precipitation for 48 hours. Filter again using a Buchner funnel to collect the precipitate, and wash with deionized water until the washing liquid is neutral. Dry under vacuum at 45°C to obtain mixture 1.
[0027] Step 2: Add 2g of mixture 1 and 0.3g of melamine to 20g of N,N-dimethylformamide, stir at 70℃ until completely dissolved, then add 0.3g of graphene oxide and continue stirring for 48h to obtain a spinning solution. Then, put the obtained spinning solution into a spinning device (20kV, 1.0mL / h, receiving distance of 15cm) for spinning to obtain the precursor.
[0028] Step 3: Transfer the precursor to an alumina crucible and heat it to 300°C in a muffle furnace at a heating rate of 1°C / min. After holding at this temperature for 5 hours, heat-stable fibers are obtained. Under a nitrogen atmosphere, transfer the heat-stable fibers to a tube furnace and heat them to 1600°C at a heating rate of 10°C / min. Hold the temperature for 3 hours to obtain carbon nanofibers.
[0029] Step 4: Mix 1g of carbon nanofibers with 100mL of 5mol / L phosphoric acid solution at a specific impregnation ratio (1:1). After the mixture is left to stand at room temperature overnight, transfer it to a drying device and dry it at 120℃. Then, place the dried mixture in a covered crucible and activate it by heating it to 600℃ at 10℃ / min under a nitrogen atmosphere and holding it at that temperature for 2 hours. After activation, allow the product to cool naturally and then wash it repeatedly with 50℃ hot water until the filtrate is close to neutral to completely remove residual phosphoric acid. Finally, transfer the washed product to a vacuum drying oven and dry it under vacuum at 120℃. After drying, grind it to obtain a porous biomass-based carbon anode material with mesopores as the main feature and rich in oxygen / phosphorus surface functional groups.
[0030] Example 3 This embodiment provides a biomass-based carbon anode material for supercapacitors, and the specific preparation steps are as follows: Step 1: Wash the sugarcane bagasse to remove impurities such as mud and sugar, and dry it to obtain dried sugarcane bagasse. Grind the dried sugarcane bagasse to below 200 mesh using a high-speed grinder. Transfer the ground sugarcane bagasse and a 50 v / v% ethanol / water solution to a round-bottom flask with a liquid ratio of 1:15. Heat the round-bottom flask to 70°C in a water bath and stir for 3 hours. After the reaction stops, filter using a Buchner funnel, collect the filtrate, add hydrochloric acid to the filtrate to adjust the pH to about 3, and let the solution stand for precipitation for 48 hours. Filter again using a Buchner funnel to collect the precipitate, and wash with deionized water until the washing liquid is neutral. Dry under vacuum at 45°C to obtain mixture 1.
[0031] Step 2: Add 2g of mixture 1 and 0.3g of melamine to 20g of N,N-dimethylformamide, stir at 70℃ until completely dissolved, then add 0.5g of graphene oxide and continue stirring for 48h to obtain a spinning solution. Then, put the obtained spinning solution into a spinning device (20kV, 1.0mL / h, receiving distance of 15cm) for spinning to obtain the precursor.
[0032] Step 3: Transfer the precursor to an alumina crucible and heat it to 300°C in a muffle furnace at a heating rate of 1°C / min. After holding at this temperature for 5 hours, heat-stable fibers are obtained. Under a nitrogen atmosphere, transfer the heat-stable fibers to a tube furnace and heat them to 1600°C at a heating rate of 10°C / min. Hold the temperature for 3 hours to obtain carbon nanofibers.
[0033] Step 4: Mix 1g of carbon nanofibers with 100mL of 5mol / L phosphoric acid solution at a specific impregnation ratio (1:1). After the mixture is left to stand at room temperature overnight, transfer it to a drying device and dry it at 120℃. Then, place the dried mixture in a covered crucible and activate it by heating it to 600℃ at 10℃ / min under a nitrogen atmosphere and holding it at that temperature for 2 hours. After activation, allow the product to cool naturally and then wash it repeatedly with 50℃ hot water until the filtrate is close to neutral to completely remove residual phosphoric acid. Finally, transfer the washed product to a vacuum drying oven and dry it under vacuum at 120℃. After drying, grind it to obtain a porous biomass-based carbon anode material with mesopores as the main feature and rich in oxygen / phosphorus surface functional groups.
[0034] Example 4 This embodiment provides a biomass-based carbon anode material for supercapacitors, and the specific preparation steps are as follows: Step 1: Wash the sugarcane bagasse to remove impurities such as mud and sugar, and dry it to obtain dried sugarcane bagasse. Grind the dried sugarcane bagasse to below 200 mesh using a high-speed grinder. Transfer the ground sugarcane bagasse and a 50 v / v% ethanol / water solution to a round-bottom flask with a liquid ratio of 1:15. Heat the round-bottom flask to 70°C in a water bath and stir for 3 hours. After the reaction stops, filter using a Buchner funnel, collect the filtrate, add hydrochloric acid to the filtrate to adjust the pH to about 3, and let the solution stand for precipitation for 48 hours. Filter again using a Buchner funnel to collect the precipitate, and wash with deionized water until the washing liquid is neutral. Dry under vacuum at 45°C to obtain mixture 1.
[0035] Step 2: Add 3g of mixture 1 and 0.3g of melamine to 20g of N,N-dimethylformamide, stir at 70℃ until completely dissolved, add 0.2g of graphene oxide, and continue stirring for 48h to obtain a spinning solution. Then, put the obtained spinning solution into a spinning device (20kV, 1.0mL / h, receiving distance of 15cm) for spinning to obtain the precursor.
[0036] Step 3: Transfer the precursor to an alumina crucible and heat it to 300°C in a muffle furnace at a heating rate of 1°C / min. After holding at this temperature for 5 hours, heat-stable fibers are obtained. Under a nitrogen atmosphere, transfer the heat-stable fibers to a tube furnace and heat them to 1600°C at a heating rate of 10°C / min. Hold the temperature for 3 hours to obtain carbon nanofibers.
[0037] Step 4: Mix 1g of carbon nanofibers with 100mL of 5mol / L phosphoric acid solution at a specific impregnation ratio (1:1). After the mixture is left to stand at room temperature overnight, transfer it to a drying device and dry it at 120℃. Then, place the dried mixture in a covered crucible and activate it by heating it to 600℃ at 10℃ / min under a nitrogen atmosphere and holding it at that temperature for 2 hours. After activation, allow the product to cool naturally and then wash it repeatedly with 50℃ hot water until the filtrate is close to neutral to completely remove residual phosphoric acid. Finally, transfer the washed product to a vacuum drying oven and dry it under vacuum at 120℃. After drying, grind it to obtain a porous biomass-based carbon anode material with mesopores as the main feature and rich in oxygen / phosphorus surface functional groups.
[0038] Example 5 This embodiment provides a biomass-based carbon anode material for supercapacitors, and the specific preparation steps are as follows: Step 1: Wash the sugarcane bagasse to remove impurities such as mud and sugar, and dry it to obtain dried sugarcane bagasse. Grind the dried sugarcane bagasse to below 200 mesh using a high-speed grinder. Transfer the ground sugarcane bagasse and a 50 v / v% ethanol / water solution to a round-bottom flask with a liquid ratio of 1:15. Heat the round-bottom flask to 70°C in a water bath and stir for 3 hours. After the reaction stops, filter using a Buchner funnel, collect the filtrate, add hydrochloric acid to the filtrate to adjust the pH to about 3, and let the solution stand for precipitation for 48 hours. Filter again using a Buchner funnel to collect the precipitate, and wash with deionized water until the washing liquid is neutral. Dry under vacuum at 45°C to obtain mixture 1.
[0039] Step 2: Add 5g of mixture 1 and 0.3g of melamine to 25g of N,N-dimethylformamide, stir at 70℃ until completely dissolved, add 0.2g of graphene oxide, and continue stirring for 48h to obtain a spinning solution. Then, put the obtained spinning solution into a spinning device (20kV, 1.0mL / h, receiving distance of 15cm) for spinning to obtain the precursor.
[0040] Step 3: Transfer the precursor to an alumina crucible and heat it to 300°C in a muffle furnace at a heating rate of 1°C / min. After holding at this temperature for 5 hours, heat-stable fibers are obtained. Under a nitrogen atmosphere, transfer the heat-stable fibers to a tube furnace and heat them to 1600°C at a heating rate of 10°C / min. Hold the temperature for 3 hours to obtain carbon nanofibers.
[0041] Step 4: Mix 1g of carbon nanofibers with 100mL of 5mol / L phosphoric acid solution at a specific impregnation ratio (1:1). After the mixture is left to stand at room temperature overnight, transfer it to a drying device and dry it at 120℃. Then, place the dried mixture in a covered crucible and activate it by heating it to 600℃ at 10℃ / min under a nitrogen atmosphere and holding it at that temperature for 2 hours. After activation, allow the product to cool naturally and then wash it repeatedly with 50℃ hot water until the filtrate is close to neutral to completely remove residual phosphoric acid. Finally, transfer the washed product to a vacuum drying oven and dry it under vacuum at 120℃. After drying, grind it to obtain a porous biomass-based carbon anode material with mesopores as the main feature and rich in oxygen / phosphorus surface functional groups.
[0042] Comparative Example 1 Step 1: Wash the collected bagasse to remove impurities such as mud and sugar, and dry it to obtain dried bagasse. Grind the dried bagasse to below 200 mesh using a high-speed grinder. Transfer the ground bagasse and a 50 v / v% ethanol / water solution to a round-bottom flask with a liquid ratio of 1:15. Heat the round-bottom flask to 70°C in a water bath and stir for 3 hours. After the reaction stops, filter using a Buchner funnel, collect the filtrate, add hydrochloric acid to the filtrate to adjust the pH to around 3, and allow the solution to stand for precipitation for 48 hours. Filter again using a Buchner funnel to collect the precipitate, and wash with deionized water until the washings are neutral. Dry under vacuum at 45°C to obtain mixture 1.
[0043] Step 2: Add 2g of mixture 1 and 0.3g of melamine to 20g of N,N-dimethylformamide, stir at 70℃ for 48h to obtain spinning solution, and then put the obtained spinning solution into a spinning device (20kV, 1.0mL / h, receiving distance of 15cm) for spinning to obtain the precursor.
[0044] Step 3: Transfer the precursor to an alumina crucible and heat it to 300°C in a muffle furnace at a heating rate of 1°C / min. After holding at this temperature for 5 hours, heat-stable fibers are obtained. Under a nitrogen atmosphere, the heat-stable fibers are transferred to a tube furnace and heated to 1600°C at a heating rate of 10°C / min. After holding at this temperature for 3 hours, carbon nanofibers are obtained.
[0045] Step 4: Mix 1g of carbon nanofibers with 100mL of 5mol / L phosphoric acid solution at a specific impregnation ratio (1:1). Let the mixed solution stand at room temperature overnight for impregnation. Then, transfer the mixture to a drying device and dry it at 120℃. Subsequently, place the dried mixture in a covered crucible and activate it by heating it to 600℃ at 10℃ / min under a nitrogen atmosphere and holding it at that temperature for 2 hours. After activation, allow the product to cool naturally. Then, repeatedly wash the cooled product with hot water at 50℃ with stirring until the filtrate is close to neutral to completely remove residual phosphoric acid. Finally, transfer the washed product to a vacuum drying oven and dry it under vacuum at 120℃. After drying, grind it to obtain porous carbon material.
[0046] Table 1: Comparison of different biomass-based carbon anode materials used in supercapacitors
[0047] As can be seen from Table 1, the porous biomass-based carbon anode materials prepared by introducing graphene oxide in Examples 1-5 have excellent rate discharge capability and cycle capacity retention capability. The supercapacitor has the highest 4C discharge capacity retention rate of 94.8% and a 200-cycle capacity retention rate of 94.3%. In contrast, the anode material prepared in Comparative Example 1 without the introduction of graphene oxide has a 4C discharge capacity retention rate of only 88.9% and a cycle capacity retention rate of only 85.3%.
[0048] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.
Claims
1. A method for preparing a biomass-based carbon anode material for supercapacitors, characterized in that, include: Step 1: After processing the sugarcane bagasse, dry, crush, extract, filter, and wash the sediment to obtain mixture 1; Step 2: Add mixture 1 and melamine to N,N-dimethylformamide, heat and stir to dissolve, then add graphene oxide and stir to obtain a spinning solution to obtain a precursor for spinning. Step 3: The precursor is pre-sintered and sintered in a nitrogen atmosphere to obtain carbon nanofibers; Step 4: After impregnating the carbon nanofibers with phosphoric acid solution, the impregnated carbon nanofibers are activated in a nitrogen atmosphere, cooled, washed, and vacuum dried to obtain a porous biomass-based carbon anode material with mesopores as the main component and rich in oxygen / phosphorus surface functional groups.
2. The method for preparing a biomass-based carbon anode material for supercapacitors according to claim 1, characterized in that, In step 1, the extraction solvent used is an aqueous ethanol solution with a volume fraction of 40-60%, and the extraction material-to-liquid ratio is 1:(10-20).
3. The method for preparing a biomass-based carbon anode material for supercapacitors according to claim 1, characterized in that, In step 2, the mass ratio of the mixture 1, melamine, N,N-dimethylformamide and graphene oxide is (1~5):(0.1~5):(0.1~2):(10~30).
4. The method for preparing a biomass-based carbon anode material for supercapacitors according to claim 1, characterized in that, In step 2, the heating and stirring temperature is 60~80℃.
5. The method for preparing a biomass-based carbon anode material for supercapacitors according to claim 1, characterized in that, In step 3, the pre-sintering temperature is 200~400℃ and the holding time is 4~6h, and the sintering temperature is 1500~1700℃ and the holding time is 2~4h.
6. The method for preparing a biomass-based carbon anode material for supercapacitors according to claim 1, characterized in that, In step 4, the mass-to-volume ratio of the carbon nanofibers to the phosphoric acid solution is 1 g: (100~200) mL.
7. The method for preparing a biomass-based carbon anode material for supercapacitors according to claim 1, characterized in that, In step 4, the activation temperature is 500~700℃ and the holding time is 1~3h; the vacuum drying temperature is 100~140℃.
8. Biomass-based carbon anode material for supercapacitors obtained by the preparation method according to any one of claims 1 to 7.
9. The application of the biomass-based carbon anode material for supercapacitors as described in claim 8 in the preparation of supercapacitors.
10. A supercapacitor, characterized in that, It includes the biomass-based carbon anode material for supercapacitors as described in claim 8.