Preparation of nitrogen-doped porous carbon spheres based on arginine and its preparation method and application
Nitrogen-doped porous carbon spheres were prepared by reacting nitrogen-containing polymer microspheres with phthalaldehyde and arginine, which solved the problem of low carbonization yield of natural nitrogen-containing carbon precursors and achieved performance improvement of high-efficiency sodium-ion battery anode materials.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- BEIBU GULF UNIV
- Filing Date
- 2023-12-13
- Publication Date
- 2026-05-12
AI Technical Summary
Existing natural nitrogen-containing carbon precursors suffer from low carbonization yield and poor structure retention when preparing nitrogen-doped porous carbon materials, which limits the improvement of the electrochemical energy storage performance of carbon materials.
Nitrogen-containing polymer microspheres generated by the reaction of phenylenedialdehyde and arginine were used as carbon precursors. Nitrogen-doped porous carbon spheres were prepared by solvothermal reaction and carbonization treatment. Schiff base polycondensation reaction was used to maintain structural stability and high carbonization yield.
The nitrogen-doped porous carbon spheres prepared as anode materials for sodium-ion batteries exhibit excellent electrochemical sodium storage performance, with good capacity retention under different current densities, high cycle stability, and high coulombic efficiency.
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Abstract
Description
Technical Field
[0001] In the field of sodium-ion battery anode material technology, specifically, it relates to a method for preparing nitrogen-doped porous carbon spheres based on arginine and its application. Background Technology
[0002] Carbon materials are a promising electrochemical energy storage material, possessing excellent conductivity, high specific surface area, good electrochemical stability, and low cost, making them the most widely used anode material for sodium-ion batteries. However, pure carbon materials generally exhibit low specific capacity, thus their electrochemical energy storage performance needs further improvement. Chemical modification of carbon materials can imbue them with more active sites, thereby achieving higher specific capacity.
[0003] Currently, introducing heteroatoms into porous carbon materials can significantly improve their specific capacity. Nitrogen atoms are considered the best doping atom for carbon materials due to their excellent chemical properties. Nitrogen-doped porous carbon materials are mainly obtained by carbonizing nitrogen-containing carbon precursors. There are two main types of nitrogen-containing carbon precursors: synthetic nitrogen-containing polymers, such as polyaniline, polypyrrole, and polyacrylonitrile, and natural nitrogen-containing polymers, such as chitosan and amino acids. Among them, natural nitrogen-containing carbon precursors are the simplest, most efficient, and lowest cost. However, most existing natural nitrogen-containing carbon precursors suffer from low carbonization yields and poor structure retention. Therefore, how to prepare nitrogen-doped porous carbon materials with well-defined structures using natural nitrogen-containing carbon precursors remains a hot research area. Summary of the Invention
[0004] To address the above problems, this invention provides a method for preparing nitrogen-doped porous carbon spheres based on arginine and its application. This invention utilizes nitrogen-containing polymer spheres obtained by reacting phenylenedialdehyde and arginine as carbon precursors, and obtains nitrogen-doped porous carbon spheres through one-step carbonization. These spheres can be used as anode materials for sodium-ion batteries and exhibit excellent electrochemical sodium storage performance.
[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:
[0006] The first objective of this invention is to provide a method for preparing nitrogen-doped porous carbon spheres based on arginine, comprising the following steps:
[0007] Arginine and phthalaldehyde were added to the reaction solvent, mixed evenly, and then transferred to a reaction vessel for solvothermal reaction to obtain nitrogen-doped porous carbon sphere precursor.
[0008] Nitrogen-doped porous carbon spheres were obtained by carbonizing the nitrogen-doped porous carbon sphere precursor at 650-850℃ under a protective gas atmosphere.
[0009] Preferably, the molar ratio of arginine to phthalaldehyde is 1:1-1.1, and the phthalaldehyde is o-phthalaldehyde, m-phthalaldehyde, or terephthalaldehyde.
[0010] Preferably, the arginine concentration in the reaction solvent is 0.06-0.075 mmol / L; and the phthalaldehyde concentration in the reaction solvent is 0.06-0.075 mol / L.
[0011] Preferably, the reaction solvent includes ethylene glycol, water, or a combination of both.
[0012] Preferably, the temperature of the solvothermal reaction is 160-180℃ and the time is 8-10h.
[0013] Preferably, the carbonization time is 2-3 hours and the heating rate is 2-5℃ / min.
[0014] Preferably, the protective gas is helium, neon, argon or nitrogen, and the gas flow rate of the protective gas is 30-50 mL / min.
[0015] A second objective of this invention is to provide nitrogen-doped porous carbon spheres prepared by the above-described method.
[0016] A third objective of this invention is to provide the application of the above-mentioned nitrogen-doped porous carbon spheres in sodium-ion batteries, wherein the nitrogen-doped porous carbon spheres are used to prepare the negative electrode of a sodium-ion battery.
[0017] Preferably, the method for preparing the sodium-ion battery negative electrode includes the following steps:
[0018] Nitrogen-doped porous carbon spheres, binder, and conductive agent were mixed in a mass ratio of 7:2:1 and coated onto the surface of copper foil. After drying at 80°C, the mixture was vacuum dried at 60°C for 12 hours to obtain a nitrogen-doped porous carbon sphere aluminum foil composite anode material.
[0019] Compared with the prior art, the present invention has the following beneficial effects:
[0020] (1) This invention uses phenylenedialdehyde and arginine as reaction monomers to obtain arginine polymer microspheres through Schiff base polycondensation reaction. The arginine polymer contains a large number of nitrogen-containing groups and has a stable skeleton structure. When used as a carbon precursor, it can maintain structural stability and high carbonization yield (37-40%). Nitrogen-doped porous carbon spheres are obtained by one-step carbonization of arginine polymer. These spheres can be used as a negative electrode material for sodium-ion batteries and have excellent electrochemical sodium storage performance.
[0021] (2) The nitrogen-doped porous carbon spheres prepared in this invention are used to prepare sodium-ion battery anodes. The capacity reaches 132 mAh / g at a current density of 0.2 A / g. When the current density is increased to 2 A / g, the capacity can still be maintained at 84 mAh / g, and the capacity retention rate reaches 64%. When the current density is 0.5 A / g, the capacity can reach 366.7 mAh / g in the first cycle, the coulombic efficiency reaches 36.8%, and the capacity is still 107.2 mAh / g after 400 cycles. Attached Figure Description
[0022] Figure 1 This is a scanning electron microscope image of the nitrogen-doped flower-like porous carbon prepared in Example 1 of the present invention;
[0023] Figure 2 This is a scanning electron microscope image of the nitrogen-doped flower-like porous carbon prepared in Example 2 of the present invention;
[0024] Figure 3 This is a scanning electron microscope image of the nitrogen-doped flower-like porous carbon prepared in Example 3 of the present invention;
[0025] Figure 4 This is a scanning electron microscope image of the nitrogen-doped flower-like porous carbon prepared in Example 4 of the present invention;
[0026] Figure 5 This is a scanning electron microscope image of the nitrogen-doped flower-like porous carbon prepared in Comparative Example 1 of this invention.
[0027] Figure 6 The nitrogen adsorption / desorption isotherm and pore size distribution diagram are shown in Example 1 of this invention. Figure 6 In the diagram, 'a' represents the nitrogen adsorption / desorption isotherm, and 'b' represents the pore size distribution.
[0028] Figure 7 The cyclic voltammetry curve of the nitrogen-doped porous carbon spheres prepared in Example 1 of this invention as a negative electrode material for a sodium-ion battery is shown.
[0029] Figure 8 The graph shows the specific capacitance variation of the nitrogen-doped porous carbon spheres prepared in Example 1 of the present invention as a negative electrode material for a sodium-ion battery under different current densities.
[0030] Figure 9 The graph shows the cycling stability of the nitrogen-doped porous carbon spheres prepared in Example 1 of this invention as a negative electrode material for sodium-ion batteries at a current density of 0.5 A / g. Detailed Implementation
[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.
[0032] It should be noted that the technical terms used in this invention are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of this invention. Unless otherwise specified, all raw materials, reagents, instruments and equipment used in the following embodiments of this invention can be purchased from the market or prepared by existing methods.
[0033] A method for preparing nitrogen-doped porous carbon spheres based on arginine includes the following steps:
[0034] Arginine and phthalaldehyde were added to the reaction solvent, mixed evenly, and then transferred to a reaction vessel for solvothermal reaction to obtain nitrogen-doped porous carbon sphere precursor.
[0035] Nitrogen-doped porous carbon spheres were obtained by carbonizing the nitrogen-doped porous carbon sphere precursor at 650-850℃ under a protective gas atmosphere.
[0036] This invention utilizes phthalaldehyde and arginine as reactive monomers to obtain arginine polymer microspheres through Schiff base polycondensation. The arginine polymer contains a large number of nitrogen-containing groups and has a stable backbone structure. When used as a carbon precursor, it can maintain structural stability and a high carbonization yield (37%-40%).
[0037] In some preferred embodiments, the molar ratio of arginine to phthalaldehyde is 1:1-1.1, and the phthalaldehyde is o-phthalaldehyde, iso-phthalaldehyde, or terephthalaldehyde. In one specific embodiment, the phthalaldehyde is terephthalaldehyde or iso-phthalaldehyde.
[0038] In some preferred embodiments, the arginine concentration in the reaction solvent is 0.06-0.075 mmol / L; the phthalaldehyde concentration in the reaction solvent is 0.06-0.075 mol / L.
[0039] In some preferred embodiments, the reaction solvent includes ethylene glycol, water, or a combination of both. The present invention uses ethylene glycol and / or water, which can completely dissolve arginine and phthalaldehyde. During the reaction process, the polymer grows uniformly in the solution, forming a spherical morphology with a larger specific surface area, thus exposing more active sites.
[0040] In some preferred embodiments, the solvothermal reaction is carried out at a temperature of 160-180°C for 8-10 hours. In one specific embodiment, the solvothermal reaction is carried out at a temperature of 180°C for 10 hours.
[0041] In some preferred embodiments, the carbonization time is 2-3 hours and the heating rate is 2-5°C / min. In one specific embodiment, the carbonization time is 2 hours and the heating rate is 2°C / min.
[0042] In some preferred embodiments, the protective gas is helium, neon, argon, or nitrogen, and the gas flow rate of the protective gas is 30-50 mL / min.
[0043] The application of the nitrogen-doped porous carbon spheres prepared above in sodium-ion batteries, wherein the nitrogen-doped porous carbon spheres are used to prepare the anode of sodium-ion batteries, includes the following steps: mixing nitrogen-doped porous carbon spheres, binder and conductive agent in a mass ratio of 7:2:1 and coating the mixture onto the surface of copper foil, drying the surface at 80°C, and then vacuum drying at 60°C for 12 hours to obtain a nitrogen-doped porous carbon sphere aluminum foil composite anode material.
[0044] This invention obtains nitrogen-doped porous carbon spheres through one-step carbonization of arginine polymer, which can be used as a negative electrode material for sodium-ion batteries, exhibiting excellent electrochemical sodium storage performance. The nitrogen-doped porous carbon spheres prepared for use as a negative electrode for sodium-ion batteries achieve a capacity of 132 mAh / g at a current density of 0.2 A / g. When the current density is increased to 2 A / g, the capacity can still be maintained at 84 mAh / g, with a capacity retention rate of 64%. When the current density is 0.5 A / g, the capacity can reach 366.7 mAh / g in the first cycle, with a coulombic efficiency of 36.8%, and the capacity is still 107.2 mAh / g after 400 cycles.
[0045] The following specific examples will provide further explanation.
[0046] Example 1
[0047] A method for preparing nitrogen-doped porous carbon spheres based on arginine includes the following steps:
[0048] S1. Dissolve 0.52 g (0.075 mmol) arginine and 0.4 g (0.075 mmol) terephthalaldehyde in 40 mL of ethylene glycol. After mixing evenly, transfer the mixture to a high-pressure reactor and place it in an oven. Solvothermal reaction at 180 °C for 10 h. After the reaction is completed, filter the mixture and wash it with ethanol. Finally, vacuum dry it at 60 °C to obtain nitrogen-doped porous carbon sphere precursor.
[0049] S2. The nitrogen-doped porous carbon sphere precursor was placed in a nitrogen atmosphere at a flow rate of 30 mL / min and heated to 750 °C for 2 h at a heating rate of 2 °C. It was then allowed to cool naturally to room temperature to obtain nitrogen-doped porous carbon spheres. The yield of nitrogen-doped porous carbon spheres was 37%.
[0050] Example 2
[0051] A method for preparing nitrogen-doped porous carbon spheres based on arginine includes the following steps:
[0052] S1. Dissolve 0.416 g (0.06 mmol) arginine and 0.4 g (0.075 mmol) terephthalaldehyde in 40 mL of ethylene glycol. After mixing evenly, transfer the mixture to a high-pressure reactor and place it in an oven. Solvothermal reaction at 180 °C for 10 h. After the reaction is completed, filter the mixture and wash it with ethanol. Finally, vacuum dry it at 60 °C to obtain nitrogen-doped porous carbon sphere precursor.
[0053] S2. The nitrogen-doped porous carbon sphere precursor was placed in a nitrogen atmosphere at a flow rate of 30 mL / min and heated to 750 °C for 2 h at a heating rate of 2 °C. It was then allowed to cool naturally to room temperature to obtain nitrogen-doped porous carbon spheres. The yield of nitrogen-doped porous carbon spheres was 40%.
[0054] Example 3
[0055] A method for preparing nitrogen-doped porous carbon spheres based on arginine includes the following steps:
[0056] S1. Dissolve 0.52 g (0.075 mmol) arginine and 0.32 g (0.06 mmol) terephthalaldehyde in 50 mL of a mixed solution of water and ethylene glycol, with a volume ratio of water to ethylene glycol of 2:3. After mixing thoroughly, transfer the solution to a high-pressure reactor and place it in an oven. Solvothermal reaction at 180 °C for 10 h. After the reaction is complete, filter the solution and wash with ethanol. Finally, vacuum dry at 60 °C to obtain nitrogen-doped porous carbon sphere precursor.
[0057] S2. The nitrogen-doped porous carbon sphere precursor was placed in a nitrogen atmosphere at a flow rate of 50 mL / min and heated to 750 °C for 2 h at a heating rate of 2 °C. It was then allowed to cool naturally to room temperature to obtain nitrogen-doped porous carbon spheres. The yield of nitrogen-doped porous carbon spheres was 38%.
[0058] Example 4
[0059] A method for preparing nitrogen-doped porous carbon spheres based on arginine includes the following steps:
[0060] S1. Dissolve 0.52 g (0.075 mmol) arginine and 0.4 g (0.075 mmol) isophthalaldehyde in 40 mL of ethylene glycol. After mixing evenly, transfer to a high-pressure reactor and place in an oven. Solvothermal reaction at 180 °C for 10 h. After the reaction is completed, filter and wash with ethanol. Finally, vacuum dry at 60 °C to obtain nitrogen-doped porous carbon sphere precursor.
[0061] S2. The nitrogen-doped porous carbon sphere precursor was placed in a nitrogen atmosphere at a flow rate of 50 mL / min and heated to 750 °C for 2 h at a heating rate of 2 °C. It was then allowed to cool naturally to room temperature to obtain nitrogen-doped porous carbon spheres. The yield of nitrogen-doped porous carbon spheres was 37%.
[0062] Comparative Example 1
[0063] A method for preparing porous carbon spheres based on arginine includes the following steps:
[0064] S1. Dissolve 0.52 g (0.075 mmol) of arginine and 0.32 g (0.06 mmol) of terephthalaldehyde in 50 mL of a mixed solution of 1,4-dioxane and ethylene glycol, with a volume ratio of ethylene glycol to 1,4-dioxane of 2:3. After mixing thoroughly, transfer the mixture to a high-pressure reactor and place it in an oven. Solvothermal reaction is carried out at 180 °C for 10 h. After the reaction is completed, filter the mixture and wash it with ethanol. Finally, vacuum dry the mixture at 60 °C to obtain a nitrogen-doped porous carbon precursor.
[0065] S2. The nitrogen-doped porous carbon sphere precursor was placed in a nitrogen atmosphere at a flow rate of 50 mL / min and heated to 750 °C for 2 h at a heating rate of 2 °C. It was then allowed to cool naturally to room temperature to obtain nitrogen-doped porous carbon. The yield of nitrogen-doped porous carbon spheres was 40%.
[0066] The nitrogen-doped porous carbon spheres prepared in Examples 1-4 and Comparative Example 1 were characterized by scanning electron microscopy (SEM). The specific steps for SEM characterization included: fixing the prepared nitrogen-doped porous carbon spheres onto the sample stage using conductive adhesive; drying the sample stage in a vacuum drying oven for 12 hours; sputter-coating with gold; and observing the structural morphology of the samples at 10 kV using a JSM-6330F cold field emission scanning electron microscope (JEOL Ltd). The results are as follows: Figures 1-5 As shown; by Figures 1-4 It can be seen that micron-sized spheres can be obtained using water or ethylene glycol as single solvents and mixed solvents. However, when terephthalaldehyde is replaced with isophthalaldehyde, the micron-sized spheres adhere together. Figure 5It can be seen that when 1,4-dioxane is added to ethylene glycol, the micron-sized spherical morphology is destroyed, and it becomes a bulk morphology. As mentioned above, because 1,4-dioxane has low solubility for arginine, the polymer grows unevenly in the solution during the reaction process, forming a bulk morphology. The spherical morphology has a larger specific surface area than the bulk morphology, thus exposing more active sites.
[0067] The nitrogen-doped porous carbon spheres prepared in Example 1 were subjected to nitrogen adsorption / desorption tests. The adsorption / desorption isotherms and pore size distribution diagrams obtained are shown below. Figure 6 As shown in Table 1, the specific surface area and pore volume data are as follows.
[0068] The nitrogen adsorption-desorption isotherm of the sample was determined using a 3H-2000PM1 adsorption instrument manufactured by Best Instruments Technology Co., Ltd. The specific steps included: weighing 0.05g of the prepared nitrogen-doped porous carbon sphere sample; degassing the sample under vacuum at 250℃ for 6 hours before testing; and determining the specific surface area S. BET The total pore volume was calculated using the BET method, the total pore volume was calculated using the t-polt method, and the total pore size distribution was calculated using DFT theory.
[0069] Table 1. Specific surface area and pore volume data of nitrogen-doped porous carbon spheres in Example 1.
[0070] Item Specific surface area (S BET ) / m 2 / g]]> Pore volume / cm 3 / g]]> Example 1 383.6 0.24
[0071] Depend on Figure 6 It can be seen that the specific surface area of the nitrogen-doped porous carbon spheres prepared in Example 1 ranges from 270.3 m². 2 / g, pore volume is 0.24cm³ 3 / g. The nitrogen adsorption-desorption isotherms of Example 1 are all Type IV. In the region where the initial relative pressure is 0, the adsorption amount increases sharply, indicating that Example 1 has a rich microporous structure. As can be seen from the pore size distribution curve, the pore size of Example 1 is mainly concentrated in 0.4 nm and 0.5 nm.
[0072] Application Example 1
[0073] To further illustrate the beneficial effects of the present invention, the nitrogen-doped porous carbon spheres prepared in Example 1 were used as the negative electrode material for a sodium-ion battery. The electrochemical performance of the samples was measured using a CS2350M electrochemical workstation manufactured by Wuhan Koster Instruments Co., Ltd. The specific steps included: mixing nitrogen-doped porous carbon spheres, binder, and conductive agent in a 7:2:1 ratio, coating the mixture onto copper foil, drying it at 80°C until the surface was dry, then vacuum drying at 60°C for 12 hours, and stamping to obtain a 12mm electrode sheet for later use; the conductive agent was carbon black, and the binder was polyvinylidene fluoride. Using the active material as the positive electrode and the lithium metal sheet as the negative electrode, a CR-2032 type coin cell was assembled sequentially in the following order: positive electrode shell - active material electrode sheet - separator - lithium sheet - gasket - spring sheet - negative electrode shell. The separator was a PP separator, and the electrolyte was a 1M lithium hexafluorophosphate (LiPF6) solution, with a solvent consisting of ethylene carbonate (EC) and diethyl carbonate (DEC) in a 1:1 volume ratio.
[0074] Figure 7 This is the cyclic voltammetry curve for Example 1. (From...) Figure 7 It can be seen that the reduction peaks around 0.4V in the first two cycles are related to the formation of the SEI film. By the fifth cycle, the reduction peak is around 0.8V, which is related to the intense adsorption of Na atoms at the micropores and defects of the carbon material.
[0075] Figure 8 This is a graph showing the capacity variation of Example 1 under different current densities. Figure 8 As can be seen, Example 1 exhibits good rate performance. The capacity reaches 132 mAh / g at a current density of 0.2 A / g, and when the current density is increased to 2 A / g, the capacity can still be maintained at 84 mAh / g, with a capacity retention rate of 64%.
[0076] Figure 9 This is the cyclic stability diagram of Example 1. (From...) Figure 9 It can be seen that Example 1, as a sodium-ion battery anode material, has good cycle stability. When the current density is 0.5 A / g, the capacity in the first cycle can reach 366.7 mAh / g, the coulombic efficiency reaches 36.8%, and the capacity is still 107.2 mAh / g after 400 cycles.
[0077] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.
[0078] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.
Claims
1. A method for preparing nitrogen-doped porous carbon spheres based on arginine, characterized in that, Includes the following steps: Arginine and phthalaldehyde were added to the reaction solvent, mixed evenly, and then transferred to a reaction vessel for solvothermal reaction to obtain nitrogen-doped porous carbon sphere precursor. The molar ratio of arginine to phthalaldehyde is 1:1-1.1; The reaction solvent includes ethylene glycol and water, or a combination of two of them. Nitrogen-doped porous carbon spheres were obtained by carbonizing the nitrogen-doped porous carbon sphere precursor at 650-850℃ under a protective gas atmosphere.
2. The method for preparing nitrogen-doped porous carbon spheres based on arginine according to claim 1, characterized in that, The phthalaldehyde is o-phthalaldehyde, iso-phthalaldehyde, or terephthalaldehyde.
3. The method for preparing nitrogen-doped porous carbon spheres based on arginine according to claim 1, characterized in that, The arginine concentration in the reaction solvent is 0.06-0.075 mmol / L; the phthalaldehyde concentration in the reaction solvent is 0.06-0.075 mol / L.
4. The method for preparing nitrogen-doped porous carbon spheres based on arginine according to claim 1, characterized in that, The solvothermal reaction is carried out at a temperature of 160-180℃ for 8-10 hours.
5. The method for preparing nitrogen-doped porous carbon spheres based on arginine according to claim 1, characterized in that, The carbonization time is 2-3 hours, and the heating rate is 2-5℃ / min.
6. The method for preparing nitrogen-doped porous carbon spheres based on arginine according to claim 1, characterized in that, The protective gas is helium, neon, argon, or nitrogen, and the gas flow rate is 30-50 mL / min.
7. A nitrogen-doped porous carbon sphere prepared by the preparation method according to any one of claims 1-6.
8. The application of the nitrogen-doped porous carbon spheres according to claim 7 in a sodium-ion battery, characterized in that, The nitrogen-doped porous carbon spheres are used to prepare the anode of sodium-ion batteries.
9. The application according to claim 8, characterized in that, The method for preparing the sodium-ion battery negative electrode includes the following steps: Nitrogen-doped porous carbon spheres, binder, and conductive agent were mixed in a mass ratio of 7:2:1 and coated onto the surface of copper foil. After drying at 80°C, the mixture was vacuum dried at 60°C for 12 hours to obtain a nitrogen-doped porous carbon sphere aluminum foil composite anode material.