A nitrogen-doped graphene self-assembled porous carbon material, a preparation method and application thereof

Abstract

This invention belongs to the field of electrode material technology and discloses a nitrogen-doped graphene self-assembled porous carbon material, its preparation method, and its application. The preparation method includes: (1) first impregnating melamine sponge with a pretreatment solution, and then extruding it to obtain the treated melamine sponge; (2) immersing the treated melamine sponge in a reaction solution and reacting it under a protective gas atmosphere to obtain a melamine-based graphene self-assembled precursor material; (3) carbonizing the melamine-based graphene self-assembled precursor material to obtain an N-doped graphene self-assembled porous carbon material; wherein, the pretreatment solution includes a first solvent, a catalyst, and an optional molten salt; the reaction solution includes a second solvent and aromatic hydrocarbons. The nitrogen-doped graphene self-assembled porous carbon material prepared by this invention has a high specific surface area, strong conductivity, good wettability, and excellent capacitance and cycling performance.

Description

Technical Field

[0001] This invention relates to the field of electrode materials technology, and more specifically, to a nitrogen-doped graphene self-assembled porous carbon material, its preparation method, and its application. Background Technology

[0002] Supercapacitors are green, safe, and efficient energy storage and conversion devices with advantages such as high power density, long cycle life, fast charge and discharge speed, high safety factor, environmental friendliness, and low cost. They are widely used in new energy vehicles, information and communication, aerospace, and defense technology. Electrode materials are the core of supercapacitors and one of the important factors affecting their electrochemical performance.

[0003] In recent years, graphene has been widely used as an electrode material for supercapacitors due to its ultra-high specific surface area (2630 m²g⁻¹), high conductivity, and theoretical specific capacitance (550 F / g). However, the strong van der Waals forces between graphene sheets make them prone to stacking and agglomeration in practical applications, resulting in an actual specific surface area (<500 m² / g) that is much smaller than the theoretical value, thus failing to fully realize its advantages as a supercapacitor electrode material. Moreover, the surface of carbon materials is hydrophobic, leading to poor wettability between the electrolyte and the pore surface, increasing contact resistance and affecting capacitance performance. Summary of the Invention

[0004] The purpose of this invention is to provide a nitrogen-doped graphene self-assembled porous carbon material, its preparation method, and its applications. Using aromatic hydrocarbons as raw materials and melamine sponge as a template, graphene is generated through a condensation reaction by chemically bonding with the carbon-nitrogen bonds in the melamine sponge. This graphene then self-assembles into a three-dimensional network structure, which is subsequently carbonized to obtain a nitrogen-doped graphene self-assembled porous carbon material. By bonding with the carbon-nitrogen bonds on the melamine sponge surface, the large π-bond interactions between graphene sheets are broken, effectively solving the problem of easy stacking of graphene materials. The melamine sponge framework provides abundant nitrogen sources, which, after high-temperature carbonization, can introduce structural nitrogen into the graphene structure, thereby improving the wettability of the graphene porous material to the electrolyte and generating a pseudocapacitive reaction in the supercapacitor electrode, increasing the specific capacitance and improving capacitance performance. The nitrogen-doped graphene self-assembled porous carbon material prepared by this invention has a high specific surface area, strong conductivity, good wettability, and excellent capacitance and cycling performance.

[0005] A first aspect of the present invention provides a method for preparing nitrogen-doped graphene self-assembled porous carbon materials, the method comprising:

[0006] (1) First, the melamine sponge is impregnated with a pretreatment solution and then extruded to obtain the treated melamine sponge.

[0007] (2) The treated melamine sponge is immersed in the reaction solution and reacted under a protective gas atmosphere to obtain melamine-based graphene self-assembled precursor material.

[0008] (3) The melamine-based graphene self-assembled precursor material is carbonized to obtain N-doped graphene self-assembled porous carbon material.

[0009] The pretreatment solution includes a first solvent, a catalyst, and an optional molten salt; the reaction solution includes a second solvent and aromatics.

[0010] A second aspect of the present invention provides an N-doped graphene self-assembled porous carbon material prepared by the above-described preparation method.

[0011] A third aspect of the present invention provides the application of the above-mentioned N-doped graphene self-assembled porous carbon material as a supercapacitor electrode material.

[0012] The technical solution of the present invention has the following beneficial effects:

[0013] By combining with the carbon-nitrogen bonds on the surface of melamine sponge, the large π-bond interactions between graphene sheets are broken, effectively solving the problem of easy stacking of graphene materials. The melamine sponge framework provides abundant nitrogen sources, which can be introduced into the graphene structure after high-temperature carbonization, thereby improving the wettability of the graphene porous material to the electrolyte and generating pseudocapacitive reactions in the supercapacitor electrodes, increasing specific capacitance and improving capacitance performance. The nitrogen-doped graphene self-assembled porous carbon material prepared by this invention has a high specific surface area, strong conductivity, good wettability, and excellent capacitance and cycling performance.

[0014] By using aromatic hydrocarbons of different structural sizes to condense into different graphene structures as self-assembling module groups, the pore structure and distribution of porous materials can be controlled.

[0015] The method of this invention is simple, the conditions are mild and controllable, and it has good prospects for industrial application.

[0016] Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0017] Exemplary embodiments of the present invention will be described in more detail with reference to the accompanying drawings.

[0018] Figure 1 A scanning electron microscope image of an N-doped graphene self-assembled porous carbon material according to Embodiment 1 of the present invention is shown.

[0019] Figure 2The Raman spectrum of the N-doped graphene self-assembled porous carbon material according to Embodiment 1 of the present invention is shown. The vertical axis represents peak intensity, and the horizontal axis represents the wavenumber of the Raman spectrum.

[0020] Figure 3 The charge-discharge curves of the N-doped graphene self-assembled porous carbon material according to Embodiment 1 of the present invention are shown at different current densities.

[0021] Figure 4 The cycling performance diagram of the N-doped graphene self-assembled porous carbon material according to Embodiment 1 of the present invention is shown. Detailed Implementation

[0022] Preferred embodiments of the invention will now be described in more detail. While preferred embodiments of the invention are described below, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein.

[0023] A first aspect of the present invention provides a method for preparing nitrogen-doped graphene self-assembled porous carbon materials, the method comprising:

[0024] (1) First, the melamine sponge is impregnated with a pretreatment solution and then extruded to obtain the treated melamine sponge.

[0025] (2) The treated melamine sponge is immersed in the reaction solution and reacted under a protective gas atmosphere to obtain melamine-based graphene self-assembled precursor material.

[0026] (3) The melamine-based graphene self-assembled precursor material is carbonized to obtain N-doped graphene self-assembled porous carbon material.

[0027] The pretreatment solution includes a first solvent, a catalyst, and an optional molten salt; the reaction solution includes a second solvent and aromatics.

[0028] In this invention, melamine sponge is used as a template and aromatic hydrocarbons are used as raw materials. Graphene structural units are generated by chemical bonding and condensation reaction with the template. These units are then self-assembled into a three-dimensional network structure and carbonized to obtain a nitrogen-doped graphene self-assembled porous carbon material.

[0029] According to the present invention, preferably, in step (1), the impregnation treatment is: immersing the melamine sponge in the pretreatment solution and then stirring;

[0030] Preferably, the stirring rate is 300 r / min to 900 r / min, and the stirring time is 10 to 60 min;

[0031] The extrusion process involves squeezing out excess pretreatment solution from the melamine sponge.

[0032] According to the present invention, step (1) can preferably be performed multiple times, preferably 1-3 times.

[0033] According to the present invention, preferably, in step (2), the reaction temperature is 30-100°C and the time is 1-10h;

[0034] In this invention, preferably, in step (2), the reaction system is placed under magnetic stirring conditions, and the stirring rate is 300 r / min to 900 r / min.

[0035] After the reaction, excess reaction liquid is squeezed out, washed with water, and dried to obtain the melamine-based graphene self-assembled precursor material.

[0036] According to the present invention, preferably, the catalyst is a Lewis acid, and preferably includes at least one of aluminum chloride, trimethylaluminum, aluminum bromide, ferric chloride, boron trichloride, antimony chloride, copper chloride, cuprous iodide, cuprous bromide, boron trifluoride, tin tetrachloride, titanium tetrachloride and silver trifluoromethanesulfonate.

[0037] The molten salt includes at least one of sodium chloride, sodium nitrate, sodium sulfate, barium chloride, calcium chloride, calcium sulfate, potassium chloride, potassium sulfate, and potassium nitrate.

[0038] The aromatic hydrocarbon is a polycyclic aromatic hydrocarbon, preferably including at least one of naphthalene, biphenylene, methylnaphthalene, phenanthrene, pyrene, fluorene, anthracene, indene, benzo[a]pyrene, chamomile blue, tetraphenylene, pentaphenylene, trinaphthalene, hexaphenylene and heptaphenylcyclopentadiene;

[0039] The first solvent and the second solvent each independently include at least one of dichloroethane, dichloromethane, chloroform, carbon tetrachloride, ethyl acetate, and xylene.

[0040] In this invention, the aromatic hydrocarbons contain fused ring structures, which are structural units for the condensation of graphene. Under the action of a catalyst, graphene structures with different structures can be designed and controlled to synthesize, thereby providing structural units for the self-assembly of porous materials with different pore structures.

[0041] In this invention, the dehydrogenation and cyclization of aromatic cationic polymerization catalyzed by Lewis acid to form graphene structure has low reaction efficiency, making it difficult to obtain graphene structure with large molecular weight. The presence of molten salt can promote the conversion of the reaction and increase the degree of condensation. The graphene self-assembled precursor structure with larger molecular weight is formed by condensation on the surface of the template agent (melamine sponge).

[0042] According to the present invention, preferably, the volume ratio of the pretreatment solution, the reaction solution and the melamine sponge is 1:1-3:1;

[0043] The molar ratio of the aromatic hydrocarbon to the catalyst is 1:(0.5-5), preferably 1:(1-2);

[0044] The molar ratio of the molten salt to the aromatic hydrocarbon is (0-3):1, preferably (1.5-2):1.

[0045] According to the present invention, preferably, in step (3), the carbonization treatment is to heat the melamine-based graphene self-assembly precursor material to 300-600°C for 1-3 hours under a nitrogen atmosphere, and then mix it with an activator and carbonize it at 600-900°C for 1-5 hours to obtain the carbonized product.

[0046] Preferably, after the carbonization treatment, the carbonization product is washed with water, ultrasonically treated and dried to obtain N-doped graphene self-assembled porous carbon material.

[0047] Preferably, the mass ratio of the melamine-based graphene self-assembly precursor material to the activator is 1:(1-3).

[0048] In this invention, the graphene self-assembled structure in the graphene self-assembled precursor forms a connection at high temperature to obtain a three-dimensional network structure, and under the activation of the activator, more fine micropores are generated, which further improves the porosity and specific surface area of ​​the material.

[0049] Molten salt is liquid at high temperatures and flows between graphene sheets, acting as a separator to prevent product aggregation and network collapse. This allows the self-assembled graphene structure on the melamine template surface to be maintained. Furthermore, it promotes the diffusion and activation of the activator within the material, resulting in a better synergistic effect between the activator and the formation of more porous structures.

[0050] The melamine sponge skeleton provides abundant nitrogen sources, which can be introduced into the graphene structure after high-temperature carbonization. This improves the wettability of the graphene porous material to the electrolyte and generates pseudocapacitive reactions in the supercapacitor electrodes, increasing the specific capacitance and improving the capacitance performance.

[0051] A second aspect of the present invention provides an N-doped graphene self-assembled porous carbon material prepared by the above-described preparation method.

[0052] According to the present invention, preferably, the N-doped graphene self-assembled porous carbon material has a three-dimensional network structure;

[0053] Preferably, the specific surface area of ​​the N-doped graphene self-assembled porous carbon material is 1500 m². 2 / g~3070m 2 / g, nitrogen content is 1-10%, specific capacitance is 187F / g-357F / g at a current density of 0.05A / g.

[0054] A third aspect of the present invention provides the application of the above-mentioned N-doped graphene self-assembled porous carbon material as a supercapacitor electrode material.

[0055] The present invention is further illustrated by the following examples:

[0056] The melamine sponges used in the following examples were purchased from Henan Aireco New Material Technology Co., Ltd., with the brand name RYL and a density of 8 kg / m³. 3 ;

[0057] In the following embodiments, the specific capacitance test conditions at a current density of 0.05 A / g are as follows: the prepared porous carbon material, carbon black, and polyvinylidene fluoride emulsion are mixed uniformly in a mass ratio of 85:10:5 to form an electrode sheet with a thickness of approximately 0.5 mm, which is then dried in a vacuum oven at 120 degrees Celsius for 24 hours. The electrode sheet is then assembled and a coin-type supercapacitor is prepared using a 6 mol / L KOH solution as the electrolyte. The electrochemical performance is tested using a Blue Battery testing system at a current density of 0.05 A / g.

[0058] In Example 1 Figure 1 The test conditions were as follows: button supercapacitors were prepared according to the above method, and the Blue Battery test system was used to test them under the following different current density conditions: 0.05A / g, 0.1A / g, 0.5A / g, 1A / g, 2A / g.

[0059] Example 1

[0060] Preparation of pretreatment solution: 6.7g aluminum chloride (molar ratio of naphthalene to aluminum chloride 1:2) and 2.9g sodium chloride (molar ratio of naphthalene to sodium chloride 1:2) were added to 20ml of dichloromethane, nitrogen gas was bubbled through at room temperature, and magnetic stirring was carried out for 0.5h.

[0061] Preparation of reaction solution: 3.2g of naphthalene was dissolved in 20ml of dichloromethane, bubbled with nitrogen at room temperature, and magnetically stirred for 0.5h.

[0062] Step 1: Add 0.16g of melamine sponge to the well-stirred pretreatment solution (the volume ratio of pretreatment solution to melamine sponge is 1:1), and stir at 500r / min for 0.5h after complete immersion. Remove the sponge and squeeze out the excess pretreatment solution until no more liquid drips within 30s to obtain the treated melamine sponge.

[0063] Step 2: Immerse the treated melamine sponge in the reaction solution (the volume ratio of the reaction solution to the melamine sponge is 1:1), and react at 30°C for 6 hours under a nitrogen atmosphere and magnetic stirring at 500 r / min. Remove the reacted melamine sponge, squeeze out the excess reaction solution, wash with water, and dry to obtain the melamine-based graphene self-assembly precursor material.

[0064] Step 3: Place 0.1g of the above melamine-based graphene self-assembled precursor material in a tube furnace and carbonize it at 500℃ for 1h under a nitrogen atmosphere by heating at 10℃ / min. After taking it out, mix it with 0.3g of KOH and carbonize it at 700℃ for 1h. The carbonization product is washed with water, ultrasonically treated, and dried to obtain N-doped graphene self-assembled porous carbon material.

[0065] The N-doped graphene self-assembled porous carbon material prepared in this embodiment has a specific surface area of ​​2870 m², as tested. 2 / g, nitrogen content is 8.1% by mass, and specific capacitance is 332F / g at a current density of 0.05A / g.

[0066] like Figure 1 As shown, the N-doped graphene self-assembled porous carbon material in this embodiment has a three-dimensional network structure.

[0067] like Figure 2 The image shows the Raman spectrum of the N-doped graphene self-assembled porous carbon material from the embodiment, at 1350 cm⁻¹. -1 Peak D, 1600cm -1 The G peak of graphene is 2600–2900 cm⁻¹. -1 It is a 2D peak.

[0068] like Figure 3 As shown, the charge-discharge curves of this embodiment at different current densities exhibit slightly distorted triangular shapes, indicating that the battery has pseudocapacitance caused by the presence of N groups in the graphene.

[0069] like Figure 4 As shown, in this embodiment, the capacity retention rate is over 90% after 30,000 cycles at a current density of 1 A / g.

[0070] Example 2

[0071] Preparation of pretreatment solution: 4.1g of ferric chloride (molar ratio of pyrene to ferric chloride 1:2) and 1.7g of boron trifluoride (molar ratio of pyrene to boron trifluoride 1:1) and 4.6g of sodium chloride (molar ratio of pyrene to sodium chloride 1:2) were added to 20ml of dichloromethane. Nitrogen gas was bubbled through the solution at room temperature and the mixture was magnetically stirred for 0.5h.

[0072] Preparation of reaction solution: 5.1 g of pyrene was dissolved in 20 ml of dichloromethane, and the mixture was bubbled with nitrogen at room temperature and magnetically stirred for 0.5 h.

[0073] Step 1: Add 0.16g of melamine sponge to the well-stirred pretreatment solution (the volume ratio of pretreatment solution to melamine sponge is 1:1), and stir at 500r / min for 0.5h after complete immersion. Remove the sponge and squeeze out the excess pretreatment solution until no more liquid drips within 30s to obtain the treated melamine sponge.

[0074] Step 2: Immerse the treated melamine sponge in the reaction solution (the volume ratio of the reaction solution to the melamine sponge is 1:1), and react at 30°C for 6 hours under a nitrogen atmosphere and magnetic stirring at 500 r / min; remove the reacted melamine sponge, squeeze out the excess reaction solution, wash with water, and dry to obtain the melamine-based graphene self-assembly precursor material.

[0075] Step 3: Place 0.1g of the above-mentioned melamine-based graphene self-assembled precursor material in a tube furnace and carbonize it at 500°C for 1 hour under a nitrogen atmosphere at a rate of 10°C / min. After removal, mix it with 0.3g of KOH and carbonize it at 700°C for 1 hour. The carbonized product is washed with water, ultrasonically treated, and dried to obtain graphene self-assembled porous carbon material.

[0076] The N-doped graphene self-assembled porous carbon material prepared in this embodiment has a specific surface area of ​​2650 m², as tested. 2 / g, nitrogen content is 7.9% by mass, and specific capacitance is 302F / g at a current density of 0.05A / g.

[0077] Example 3

[0078] Preparation of pretreatment solution: 1.7g of copper chloride (molar ratio of anthracene to copper chloride 1:0.5) and 0.41g of potassium chloride (molar ratio of anthracene to potassium chloride 1:0.1) were added to 20ml of dichloromethane, nitrogen gas was bubbled through the solution at room temperature, and magnetic stirring was performed for 0.5h.

[0079] Preparation of reaction solution: 4.45g of anthracene was dissolved in 20ml of dichloromethane, and the mixture was bubbled with nitrogen at room temperature and magnetically stirred for 0.5h.

[0080] Step 1: Add 0.16g of melamine sponge to the well-stirred pretreatment solution (the volume ratio of pretreatment solution to melamine sponge is 1:1), and stir at 600r / min for 0.5h after complete immersion. Remove the sponge and squeeze out the excess pretreatment solution until no more liquid drips within 30s to obtain the treated melamine sponge.

[0081] Step 2: Immerse the treated melamine sponge in the reaction solution (the volume ratio of the reaction solution to the melamine sponge is 1:1), and react at 60°C for 6 hours under a nitrogen atmosphere and magnetic stirring at 600 r / min. Remove the reacted melamine sponge, squeeze out the excess reaction solution, wash with water, and dry to obtain the melamine-based graphene self-assembly precursor material.

[0082] Step 3: Place 0.1g of the above-mentioned melamine-based graphene self-assembled precursor material in a tube furnace and carbonize it at 500°C for 1 hour under a nitrogen atmosphere at a rate of 10°C / min. After removal, mix it with 0.3g of KOH and carbonize it at 700°C for 1 hour. The carbonization product is washed with water, ultrasonically treated, and dried to obtain N-doped graphene self-assembled porous carbon material.

[0083] The N-doped graphene self-assembled porous carbon material prepared in this embodiment has a specific surface area of ​​1506 m², as tested. 2 / g, nitrogen content is 9.7%, specific capacitance is 287F / g at a current density of 0.05A / g.

[0084] Example 4

[0085] Preparation of pretreatment solution: 8.25g of calcium chloride (molar ratio of methylnaphthalene to calcium chloride 1:3) and 16.2g of ferric chloride (molar ratio of methylnaphthalene to ferric chloride 1:4) were added to 20ml of dichloromethane, nitrogen gas was bubbled through the mixture at room temperature, and magnetic stirring was carried out for 0.5h.

[0086] Preparation of reaction solution: 3.55g of methylnaphthalene was dissolved in 20ml of dichloromethane, bubbled with nitrogen at room temperature, and magnetically stirred for 0.5h.

[0087] Step 1: Add 0.16g of melamine sponge to the well-stirred pretreatment solution (the volume ratio of pretreatment solution to melamine sponge is 1:1), and stir at 600r / min for 0.5h after complete immersion. Remove the sponge and squeeze out the excess pretreatment solution until no more liquid drips within 30s to obtain the treated melamine sponge.

[0088] Step 2: Immerse the treated melamine sponge in the reaction solution (the volume ratio of the reaction solution to the melamine sponge is 1:1), and react at 60°C for 6 hours under a nitrogen atmosphere and magnetic stirring at 600 r / min. Remove the reacted melamine sponge, squeeze out the excess reaction solution, wash with water, and dry to obtain the melamine-based graphene self-assembly precursor material.

[0089] Step 3: Place 0.1g of the above melamine-based graphene self-assembled precursor material in a tube furnace and carbonize it at 500℃ for 1h under a nitrogen atmosphere at a rate of 10℃ / min. After removal, mix it with 0.3g of KOH and carbonize it at 700℃ for 1h. The carbonization product is washed with water, ultrasonically treated, and dried to obtain N-doped graphene self-assembled porous carbon material.

[0090] The N-doped graphene self-assembled porous carbon material prepared in this embodiment has a specific surface area of ​​3070 m² / g, a nitrogen content of 9.1%, and a specific capacitance of 357 F / g at a current density of 0.05 A / g, as tested.

[0091] Example 5

[0092] Preparation of pretreatment solution: Add 5g of copper chloride (molar ratio of phenanthrene to copper chloride 1:1.5) and 14.25g of titanium tetrachloride (molar ratio of phenanthrene to titanium tetrachloride 1:3) to 20ml of dichloromethane, bubble with nitrogen gas at room temperature, and stir magnetically for 0.5h.

[0093] Preparation of reaction solution: Dissolve 4.45g of phenanthrene in 20ml of dichloromethane, bubble with nitrogen at room temperature, and stir magnetically for 0.5h.

[0094] Step 1: Add 0.16g of melamine sponge to the well-stirred pretreatment solution (the volume ratio of pretreatment solution to melamine sponge is 1:1), and stir at 500r / min for 0.5h after complete immersion. Remove the sponge and squeeze out the excess pretreatment solution until no more liquid drips within 30s to obtain the treated melamine sponge.

[0095] Step 2: Immerse the treated melamine sponge in the reaction solution (the volume ratio of the reaction solution to the melamine sponge is 1:1), and react at 30°C for 6 hours under a nitrogen atmosphere and magnetic stirring at 500 r / min; remove the reacted melamine sponge, squeeze out the excess reaction solution, wash with water, and dry to obtain the melamine-based graphene self-assembly precursor material.

[0096] Step 3: Place 0.1g of the above-mentioned melamine-based graphene self-assembled precursor material in a tube furnace and carbonize it at 500°C for 1 hour under a nitrogen atmosphere at a rate of 10°C / min. After removal, mix it with 0.3g of KOH and carbonize it at 700°C for 1 hour. The carbonization product is washed with water, ultrasonically treated, and dried to obtain N-doped graphene self-assembled porous carbon material.

[0097] The N-doped graphene self-assembled porous carbon material prepared in this embodiment has a specific surface area of ​​2390 m², as tested. 2 / g, nitrogen content is 6.7% by mass, and specific capacitance is 289F / g at a current density of 0.05A / g.

[0098] Example 6

[0099] Preparation of pretreatment solution: 6.7g aluminum chloride (molar ratio of naphthalene to aluminum chloride 1:2) and 2.9g sodium chloride (molar ratio of naphthalene to sodium chloride 1:2) were added to 20ml of dichloromethane, nitrogen gas was bubbled through at room temperature, and magnetic stirring was carried out for 0.5h.

[0100] Preparation of reaction solution: 3.2g of naphthalene was dissolved in 20ml of dichloromethane, bubbled with nitrogen at room temperature, and magnetically stirred for 0.5h.

[0101] Step 1: Add 0.1g of melamine sponge to the well-stirred pretreatment solution (the volume ratio of pretreatment solution to melamine sponge is 2:1), and stir at 500r / min for 0.5h after complete immersion. Remove the sponge and squeeze out the excess pretreatment solution until no more liquid drips within 30s to obtain the treated melamine sponge.

[0102] Step 2: Immerse the treated melamine sponge in the reaction solution (the volume ratio of the reaction solution to the melamine sponge is 2:1), and react at 60°C for 10 hours under a nitrogen atmosphere and magnetic stirring at 500 r / min; remove the reacted melamine sponge, squeeze out the excess reaction solution, wash with water, and dry to obtain the melamine-based graphene self-assembly precursor material.

[0103] Step 3: Place 0.1g of the above-mentioned melamine-based graphene self-assembled precursor material in a tube furnace and carbonize it at 500°C for 1 hour under a nitrogen atmosphere at a rate of 10°C / min. After removal, mix it with 0.3g of KOH and carbonize it at 700°C for 1 hour. The carbonization product is washed with water, ultrasonically treated, and dried to obtain N-doped graphene self-assembled porous carbon material.

[0104] The N-doped graphene self-assembled porous carbon material prepared in this embodiment has a specific surface area of ​​2880 m², as tested. 2 / g, nitrogen content is 7.9% by mass, and specific capacitance is 324F / g at a current density of 0.05A / g.

[0105] Example 7

[0106] Preparation of pretreatment solution: 6.7g aluminum chloride (molar ratio of naphthalene to aluminum chloride 1:2) and 2.9g sodium chloride (molar ratio of naphthalene to sodium chloride 1:2) were added to 20ml of dichloroethane, nitrogen gas was bubbled through at room temperature, and magnetic stirring was carried out for 0.5h.

[0107] Preparation of reaction solution: 3.2g of naphthalene was dissolved in 20ml of dichloroethane, bubbled with nitrogen at room temperature, and magnetically stirred for 0.5h.

[0108] Step 1: Add 0.05g of melamine sponge to the well-stirred pretreatment solution (the volume ratio of pretreatment solution to melamine sponge is 3:1), and stir at 500r / min for 0.5h after complete immersion. Remove the sponge and squeeze out the excess pretreatment solution until no more liquid drips within 30s to obtain the treated melamine sponge.

[0109] Step 2: Immerse the treated melamine sponge in the reaction solution (the volume ratio of the reaction solution to the melamine sponge is 3:1), and react at 30°C for 6 hours under a nitrogen atmosphere and magnetic stirring at 500 r / min. Remove the reacted melamine sponge, squeeze out the excess reaction solution, wash with water, and dry to obtain the melamine-based graphene self-assembly precursor material.

[0110] Step 3: Place 0.1g of the above melamine-based graphene self-assembled precursor material in a tube furnace and carbonize it at 500℃ for 1h under a nitrogen atmosphere at a rate of 10℃ / min. After removal, mix it with 0.3g of KOH and carbonize it at 700℃ for 1h. The carbonization product is washed with water, ultrasonically treated, and dried to obtain N-doped graphene self-assembled porous carbon material.

[0111] The N-doped graphene self-assembled porous carbon material prepared in this embodiment has a specific surface area of ​​2850 m², as tested. 2 / g, nitrogen content is 8.2% by mass, and specific capacitance is 329F / g at a current density of 0.05A / g.

[0112] Example 8

[0113] Preparation of pretreatment solution: 6.7g aluminum chloride (molar ratio of naphthalene to aluminum chloride 1:2) and 2.9g sodium chloride (molar ratio of naphthalene to sodium chloride 1:2) were added to 20ml of dichloromethane, nitrogen gas was bubbled through at room temperature, and magnetic stirring was carried out for 0.5h.

[0114] Preparation of reaction solution: 3.2g of naphthalene was dissolved in 20ml of dichloromethane, bubbled with nitrogen at room temperature, and magnetically stirred for 0.5h.

[0115] Step 1: Add 0.16g of melamine sponge to the well-stirred pretreatment solution (the volume ratio of pretreatment solution to melamine sponge is 1:1), and stir at 500r / min for 0.5h after complete immersion. Remove the sponge and squeeze out the excess pretreatment solution until no more liquid drips within 30s to obtain the treated melamine sponge.

[0116] Step 2: Immerse the treated melamine sponge in the reaction solution (the volume ratio of the reaction solution to the melamine sponge is 1:1), and react at 60°C for 10 hours under a nitrogen atmosphere and magnetic stirring at 500 r / min; remove the reacted melamine sponge, squeeze out the excess reaction solution, wash with water, and dry to obtain the melamine-based graphene self-assembly precursor material.

[0117] Step 3: Place 0.1g of the above melamine-based graphene self-assembled precursor material in a tube furnace and carbonize it at 600℃ for 1h under a nitrogen atmosphere at a rate of 10℃ / min. After removal, mix it with 0.3g of KOH and carbonize it at 900℃ for 1h. The carbonization product is washed with water, ultrasonically treated, and dried to obtain N-doped graphene self-assembled porous carbon material.

[0118] The N-doped graphene self-assembled porous carbon material prepared in this embodiment has a specific surface area of ​​2870 m², as tested. 2 / g, nitrogen content is 2.3%, specific capacitance is 270F / g at a current density of 0.05A / g.

[0119] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A method for preparing a nitrogen-doped graphene self-assembled porous carbon material, characterized in that, The preparation method includes: (1) First, the melamine sponge is impregnated with a pretreatment solution and then extruded to obtain the treated melamine sponge; (2) The treated melamine sponge is immersed in the reaction solution and reacted under a protective gas atmosphere to obtain melamine-based graphene self-assembled precursor material; (3) The melamine-based graphene self-assembled precursor material is subjected to carbonization treatment to obtain N-doped graphene self-assembled porous carbon material. The pretreatment solution includes a first solvent, a catalyst, and an optional molten salt; the reaction solution includes a second solvent and aromatics. In step (3), the carbonization process involves heating the melamine-based graphene self-assembled precursor material to 300-600°C for 1-3 hours under a nitrogen atmosphere, then mixing it with an activator and carbonizing it at 600-900°C for 1-5 hours to obtain the carbonized product.

2. The preparation method according to claim 1, wherein, In step (1), the impregnation process is as follows: after immersing the melamine sponge in the pretreatment solution, it is stirred.

3. The preparation method according to claim 2, wherein, The stirring rate is 300 r / min to 900 r / min, and the stirring time is 10 to 60 min.

4. The production method according to claim 1, wherein In step (1), the extrusion process is to extrude the excess pretreatment solution from the melamine sponge.

5. The production method according to claim 1, wherein Step (1) can be performed multiple times.

6. The production method according to claim 1, wherein Step (1) is performed 1-3 times.

7. The production method according to claim 1, wherein In step (2), the reaction temperature is 30~100℃ and the time is 1~10h; After the reaction, excess reaction liquid is squeezed out, washed with water, and dried to obtain the melamine-based graphene self-assembled precursor material.

8. The production method according to claim 1, wherein The catalyst is a Lewis acid; The molten salt includes at least one of sodium chloride, sodium nitrate, sodium sulfate, barium chloride, calcium chloride, calcium sulfate, potassium chloride, potassium sulfate, and potassium nitrate. The aromatic hydrocarbon is a polycyclic aromatic hydrocarbon; The first solvent and the second solvent each independently include at least one of dichloroethane, dichloromethane, chloroform, carbon tetrachloride, ethyl acetate, and xylene.

9. The production method according to claim 8, wherein The catalyst includes at least one of aluminum chloride, trimethylaluminum, aluminum bromide, ferric chloride, boron trichloride, antimony chloride, copper chloride, cuprous iodide, cuprous bromide, boron trifluoride, tin tetrachloride, titanium tetrachloride, and silver trifluoromethanesulfonate.

10. The production method according to claim 8, wherein The aromatic hydrocarbons include at least one of naphthalene, biphenylene, methylnaphthalene, phenanthrene, pyrene, fluorene, anthracene, indene, benzo[a]pyrene, chamomile blue, tetraphenylene, pentaphenylene, triphenylene, hexaphenylene, and heptaphenylcyclopentadiene.

11. The production method according to claim 1, wherein The volume ratio of the pretreatment solution, the reaction solution, and the melamine sponge is 1:1 to 3:1; The molar ratio of the aromatic hydrocarbon to the catalyst is 1:(0.5~5); The molar ratio of the molten salt to the aromatic hydrocarbon is (0~3):

1.

12. The method of making according to claim 11, wherein, The molar ratio of the aromatic hydrocarbon to the catalyst is 1:(1~2); The molar ratio of the molten salt to the aromatic hydrocarbon is (1.5~2):

1.

13. The preparation method according to claim 1, wherein, After the carbonization treatment, the carbonization product is washed with water, ultrasonically treated and dried to obtain N-doped graphene self-assembled porous carbon material.

14. The method of producing according to claim 1, wherein, The mass ratio of the melamine-based graphene self-assembled precursor material to the activator is 1:(1~3).

15. N-doped graphene self-assembled porous carbon material prepared by the preparation method according to any one of claims 1-14.

16. The N-doped graphene self-assembled porous carbon material according to claim 15, wherein, The N-doped graphene self-assembled porous carbon material has a three-dimensional network structure.

17. The N-doped graphene self-assembled porous carbon material according to claim 16, wherein, The specific surface area of ​​the N-doped graphene self-assembled porous carbon material is 1500 m². 2 / g~3070m 2 / g, with a nitrogen content of 1~10%, and a specific capacitance of 187F / g~357F / g at a current density of 0.05A / g.

18. The application of the N-doped graphene self-assembled porous carbon material according to any one of claims 15-17 as an electrode material for supercapacitors.

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