CN113880067B - A kind of preparation method of porous carbon superstructure material - Google Patents

Abstract

The invention relates to a preparation method of a porous carbon superstructure material. It belongs to the field of material preparation science and technology. Select cyanuric chloride and 2,6-diaminoanthraquinone to undergo a nucleophilic substitution reaction in acetonitrile solvent to generate a polymer precursor, and then prepare a porous carbon superstructure material after simultaneous carbonization/chemical activation. The preparation process of the present invention is simple and does not require complicated and harsh experimental conditions. The prepared carbon superstructure material has an ultra-high specific surface area, a hierarchical porous structure, and nitrogen and oxygen heteroatoms. These characteristics enhance the interfacial wetting of the carbon superstructure material It provides a fast transport channel for ions, and can produce a significant Faradaic reaction to contribute to the pseudocapacitance. When it is used as a supercapacitor electrode material, it exhibits excellent specific capacitance, significant rate performance and superior cycle stability. It is ideal electrode materials for supercapacitors.

Description

A kind of preparation method of porous carbon superstructure material

technical field

The invention relates to a preparation method of a porous carbon superstructure material, belonging to the technical field of material preparation.

Background technique

In order to solve the problems of global fossil fuel depletion and environmental degradation, the development of sustainable and efficient energy storage technologies and devices has become an urgent need. As one of the most promising energy storage devices, carbon-based supercapacitors have been widely used in digital cameras, all-electric vehicles, and pulsed lasers in recent years due to their advantages such as fast charge and discharge speed, high power density, and long service life. . Electrode materials are the key components of supercapacitors. Among various electrode materials, carbon materials are widely used because of their outstanding advantages such as high conductivity, stable chemical properties, environmental friendliness, adjustable pore structure parameters and morphology. In order to improve the energy storage performance of supercapacitors, many studies have been devoted to the development of advanced carbon electrode materials.

As a new type of carbon material, carbon superstructure material has a regular three-dimensional structure, which can inherit the basic properties of its unit constructs and obtain additional structural advantages, such as exquisite surface structure, developed internal pores, high mechanical strength, and heteroatom content. It has many advantages such as richness, good thermal stability, stable chemical properties and high electron conduction rate, and has broad application prospects in the fields of energy storage, catalyst carrier drug delivery, and optoelectronic devices. The title of the invention is "A material with carbon superstructure, preparation method and application" (Chinese invention patent, application number 201910890355.5) reports the preparation of carbon superstructure and its application in the field of energy storage. However, preparing carbon materials with superstructured morphologies is challenging. So far, only a few synthetic methods for carbon superstructures have been reported. These methods usually require multi-step reactions and tedious assembly processes, or complex processes involving the use of complex templates and subsequent etching steps to prepare polymer precursors, which greatly limit the practical application. For example, the title of the invention is "A Novel Polyacrylonitrile System for Preparing Multifunctional Carbon Flowers and Other Superstructures" (Chinese Invention Patent, Application No. 201980048681.X) provides a method for manufacturing polyacrylonitrile nanostructured The method of carbon superstructure shape, its preparation process is: by using monomer acrylonitrile and initiator azobisisobutyronitrile to carry out free radical polymerization in organic solvent to form polyacrylonitrile superstructure shape polymer precursor, after high temperature Superstructural carbon materials are obtained after carbonization of polymer precursors. However, this method involves the use of explosive reagent azobisisobutyronitrile, which is harmful to the human body and pollutes the environment; during the polymerization process, the internal pressure of the reactor will increase rapidly, and the requirements on the reactor are relatively high. Therefore, the development of simple and efficient preparation methods for carbon superstructure materials is urgently needed.

Contents of the invention

The purpose of the invention is to disclose a preparation method of a porous carbon superstructure material. The carbon superstructure material prepared by the method of the invention has many advantages such as exquisite surface structure, high specific surface area, developed internal pores, rich heteroatom content, good thermal stability, etc., and can be used as an ideal supercapacitor electrode material.

In order to achieve the above-mentioned purpose, the present invention selects cyanuric chloride and 2,6-diaminoanthraquinone in acetonitrile solvent to generate nucleophilic substitution reaction to generate polymer precursor, and make porous carbon superstructure material after synchronous carbonization/chemical activation . The preparation process of this method is simple and does not require complex and harsh experimental conditions. The prepared carbon superstructure material has a super high specific surface area, a hierarchical porous structure, and nitrogen and oxygen heteroatoms. These features enhance the interfacial wettability of carbon electrodes, provide fast ion transport channels to achieve high-rate performance, and generate significant faradaic reactions to contribute to pseudocapacitance. When used as supercapacitor electrode materials, they exhibit excellent specific capacitance. rate performance and excellent cycle stability.

Concrete preparation process is to carry out as follows:

Weigh cyanuric chloride, 2,6-diaminoanthraquinone and acetonitrile sequentially according to the mass ratio of 1:0.9～3.9:50～200, first dissolve cyanuric chloride and 2,6-diaminoanthraquinone in acetonitrile Mix evenly, react at 30-80°C for 360 minutes at a stirring speed of 300-800 rpm, filter, wash with ethanol, and dry to obtain a polymer precursor. The polymer precursor and sodium cyanate are mixed at a ratio of 1:0.5～ Mix the mass ratio of 3, place in a tube furnace, protect with inert gas, heat to 600-1000°C for carbonization at a heating rate of 2-20°C min ^-1 , keep the temperature for 2-3 hours, and cool down to room temperature naturally, that is, porous carbon superstructural material.

The present invention has the following advantages:

1. The present invention adopts cyanuric chloride and 2,6-diaminoanthraquinone as monomer materials, forms polymer precursor through nucleophilic substitution reaction, obtains porous carbon superstructure material through synchronous carbonization/chemical activation treatment, and existing Compared with the process, the present invention has a simple process and does not need templates, complicated and severe experimental conditions and high-pressure equipment.

2. The polymer precursor synthesized in the present invention has the effect of "all-in-one", and acts as a carbon source, a nitrogen source and an oxygen source at the same time, and can effectively introduce heteroatoms into the porous carbon superstructure material skeleton evenly, Thereby enhancing the wettability of the surface when it is used as an electrode material, improving the transport and diffusion kinetics of electrolyte ions in the pores of the material, and endowing the electrode material with excellent electrochemical performance.

3. The porous carbon superstructure material prepared by the present invention is stacked by nanoparticle-embedded layered structures, has a huge specific surface area (1431-1993m ² g ^-1 ), unique micro/mesoporous structure (concentrated at 0.54 , 0.82, 1.28 and 2-10nm), and abundant nitrogen and oxygen heteroatoms (9.76-10.22/4.85-5.66wt.%), when it is used as a supercapacitor electrode material, it is shown by analysis and testing that it can be charged at 1A/g When discharging, its specific capacitance is more than 400F/g, and the capacity retention rate after 1,000,000 cycles of charging and discharging is above 90%, showing high specific capacitance and excellent cycle stability.

Description of drawings

Fig. 1 is a scanning electron microscope image of the porous carbon superstructure material prepared in Example 1 of the present invention.

Fig. 2 is the nitrogen adsorption-desorption isotherm of the porous carbon superstructure material prepared in Example 1 of the present invention.

Fig. 3 is the pore size distribution curve of the porous carbon superstructure material prepared in Example 1 of the present invention.

Fig. 4 is a scanning electron microscope image of the porous carbon superstructure material prepared in Example 2 of the present invention.

Fig. 5 is the nitrogen adsorption-desorption isotherm of the porous carbon superstructure material prepared in Example 2 of the present invention.

Fig. 6 is the pore size distribution curve of the porous carbon superstructure material prepared in Example 2 of the present invention.

Fig. 7 is a scanning electron microscope image of the porous carbon superstructure material prepared in Example 3 of the present invention.

Fig. 8 is the nitrogen adsorption-desorption isotherm of the porous carbon superstructure material prepared in Example 3 of the present invention.

Fig. 9 is the pore size distribution curve of the porous carbon superstructure material prepared in Example 3 of the present invention.

Detailed ways

Example 1

Weigh cyanuric chloride, 2,6-diaminoanthraquinone and acetonitrile in sequence according to the mass ratio of 1:2:79, first dissolve cyanuric chloride and 2,6-diaminoanthraquinone in acetonitrile, mix well, React at 70°C for 120 min at a stirring speed of 500 rpm. Filter, wash with ethanol, and dry to obtain a polymer precursor. Mix the polymer precursor with sodium cyanate at a mass ratio of 1:0.5, place it in a tube furnace, protect it with an inert gas, and heat it up at 2°C min ^-1 Heating rate to 700°C for carbonization, constant temperature for 3 hours, and natural cooling to room temperature, that is, porous carbon superstructure material.

Please see Figure 1: the product obtained in Example 1 can be seen through electron microscope scanning: it is stacked by a layered structure embedded with carbon nanoparticles, with a huge specific surface area of 1866m ² g ^-1 (Figure 2), unique micro / The mesoporous structure is concentrated at 0.54, 0.82, 1.28 and 2.73nm (Figure 3), and abundant nitrogen and oxygen heteroatoms (10.87/5.66wt.%).

Example 2

Weigh cyanuric chloride, 2,6-diaminoanthraquinone and acetonitrile successively according to the mass ratio of 1:2.9:158, first dissolve cyanuric chloride and 2,6-diaminoanthraquinone in acetonitrile and mix them uniformly, React at 70°C for 120 min at a stirring speed of 500 rpm. Filter, wash with ethanol, and dry to obtain the polymer precursor. Mix the polymer precursor with sodium cyanate at a mass ratio of 1:1, place it in a tube furnace, protect it with inert gas, and heat it up at 5°C min ^-1 Heating at a rate of 800°C for carbonization, keeping the temperature constant for 2 hours, and cooling down to room temperature naturally, the porous carbon superstructure material is obtained.

Please see Figure 4: The product obtained in Example 2 can be seen through electron microscope scanning: it is stacked by a layered structure embedded with carbon nanoparticles, with a huge specific surface area of 1431m ² g ^-1 (Figure 5), unique micro / The mesoporous structure is concentrated at 0.54, 0.82, 1.28 and 2.73nm (Figure 6), and abundant nitrogen and oxygen heteroatoms (9.76/4.85wt.%).

Example 3

Weigh cyanuric chloride, 2,6-diaminoanthraquinone and acetonitrile in sequence according to the mass ratio of 1:1.5:158, first dissolve cyanuric chloride and 2,6-diaminoanthraquinone in acetonitrile and mix them uniformly, React at 70°C for 120 min at a stirring speed of 350 rpm. Filter, wash with ethanol, and dry to obtain the polymer precursor. Mix the polymer precursor with sodium cyanate at a mass ratio of 1:1, place it in a tube furnace, protect it with inert gas, and heat it up at 3°C min ^-1 Heating at a rate of 700°C for carbonization, keeping the temperature constant for 2 hours, and cooling down to room temperature naturally, the porous carbon superstructure material is obtained.

Please see Figure 7: the product obtained in Example 3 can be seen through electron microscope scanning: it is stacked by a layered structure embedded with carbon nanoparticles, with a huge specific surface area of 1993m ² g ^-1 (Figure 8), unique micro / The mesoporous structure is concentrated at 0.54, 0.82, 1.28 and 2-10 nm (Fig. 9), and abundant nitrogen and oxygen heteroatoms (10.22/5.04wt.%).

Example 4

Weigh the porous carbon superstructure material obtained in Example 1 or 2 or 3 by mass ratio: 60wt% polytetrafluoroethylene emulsion (purchased from Shanghai Sanaifu New Material Co., Ltd): graphite=8:1:1 , after mixing evenly, place it in an oven to dry, press the dried sample on foamed nickel (purchased from Changsha Liyuan New Material Co., Ltd.) under a pressure of 20 MPa, and dry it in vacuum at 100°C for 24 hours to make electrode sheets. Using the electrode sheet as a working electrode, the electrochemical performance was tested in a 1mol/L H ₂ SO ₄ solution. When the sample electrode (being the working electrode) is charged and discharged at 1.0A/g, its specific capacitance (of Examples 1, 2, and 3) all reaches more than 400F/g, and the capacity retention rate after 1,000,000 cycles of charging and discharging is 90%. Above, exhibit high specific capacitance and superior cycle stability.

The above raw materials are commercially available reagent grade products.

Claims (1)

1. A preparation method of a porous carbon super-structure material is characterized by comprising the following steps: according to cyanuric chloride: 2, 6-diaminoanthraquinone: acetonitrile = 1:0.9 to 3.9: weighing 50-200 mass ratio, dissolving cyanuric chloride and 2, 6-diaminoanthraquinone in acetonitrile, uniformly mixing, reacting for 360min at 30-80 ℃ at the stirring speed of 300-800 rpm, filtering, washing with ethanol, drying to obtain a polymer precursor, and then preparing the polymer precursor according to the following steps: sodium cyanate = 1: weighing and mixing the materials according to the mass ratio of 0.5-3, placing the materials into a tube furnace, and protecting the materials by inert gas according to the temperature of 2-20 ℃ for min- ¹ Heating to 600-1000 ℃ for carbonization,keeping the temperature for 2-3 h, naturally cooling to room temperature to obtain the porous carbon super-structure material;

the inert gas is one of nitrogen, argon and helium;

all the raw materials are commercial reagent grade products.

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