CN110283288B

CN110283288B - Heteroatom-doped polymer nano-microsphere with cavity structure capable of being produced in large scale and preparation method thereof

Info

Publication number: CN110283288B
Application number: CN201910556107.7A
Authority: CN
Inventors: 吕荣文; 林华; 刘盈岑; 刘明辉
Original assignee: Dalian University of Technology
Current assignee: Dalian University of Technology
Priority date: 2019-06-25
Filing date: 2019-06-25
Publication date: 2020-09-29
Anticipated expiration: 2039-06-25
Also published as: CN110283288A

Abstract

The invention discloses a heteroatom-doped core-shell structure polymer nano microsphere and a preparation method thereof; the method overcomes the defects of complexity limitation of a template method and the like, adopts mild reaction temperature (room temperature), takes melamine, arylamine and aldehyde as raw materials, generates Schiff base by using the reaction rate difference of the aldehyde and general formula 3, 5-diaminobenzoic acid or 2, 4-diaminobenzenesulfonic acid in an acetone-water mixed system or a pure acetone system in the presence of 3, 5-diaminobenzoic acid or 2, 4-diaminobenzenesulfonic acid, adds arylamine and the generated Schiff base to prepare coated nano microspheres, and soaks or washes the coated nano microspheres in different solvents to obtain the nano microspheres with the core-shell structure. The process method has the advantages of simple operation, mild condition and quick reaction; the nano microsphere product prepared by the method has the advantages of controllable size and shape, uniform granularity, uniform dispersion, high yield, uniform heteroatom doping and enhanced material toughness. Has good application prospect.

Description

Heteroatom-doped polymer nano-microsphere with cavity structure capable of being produced in large scale and preparation method thereof

Technical Field

The invention belongs to the technical field of new nano materials, and particularly relates to a heteroatom-doped polymer nano microsphere with a cavity structure and a preparation method thereof.

Background

The nano-microsphere with the cavity structure has wide application in reality, and mainly comprises two structures: one is core-shell structure microsphere, and the other is hollow sphere. The core-shell structure nano-microsphere refers to a nano-particle formed by a shell and a core which are closely related. The core-shell can be organic, inorganic or biomass, so as to form various nanoparticles with different structures, and due to the diversity of the core and shell components, the nano-microsphere with the core-shell structure has various characteristics, such as optical, magnetic, electronic, mechanical and chemical properties. The hollow ball has the characteristics of special hollow structure, large internal cavity and the like. The nano-microspheres with the cavity structures can be widely applied to the fields of batteries, capacitors, sensors, drug delivery, quantum dots, photonic crystals, catalysis and the like. Whereas previous methods for synthesizing core-shell or hollow carbon nanospheres have relied primarily on templating. The hard template method has the disadvantages of complicated operation, low yield and limitation of application, and the used hard template needs to be treated by NaOH or HF and is difficult to remove; the soft template method is limited by its limited availability of templating agents and is cumbersome and long-flowing.

The high energy density and high capacity of lithium-sulfur batteries are attracting much attention, and the energy density of lithium-sulfur batteries can reach about five times that of common lithium batteries, so that the lithium-sulfur batteries have a wide application background. Although the lithium-sulfur battery has wide application prospect, the positive electrode of the battery has a plurality of problems. For example, poor conductivity of sulfur results in low specific capacity of the battery, volume expansion of sulfur in the lithiation process results in destruction of the positive electrode material, diffusion of polysulfide results in severe capacity attenuation, and low coulombic efficiency (shuttle effect). Nanoparticles with cavities have the following advantages: firstly, a high-conductivity carbon shell is synthesized, and then sulfur is doped, so that the problem of poor sulfur conductivity can be solved, secondly, the problem of volume expansion of sulfur in the lithiation process can be relieved due to the existence of an internal cavity, and thirdly, the shell doped with heteroatoms can reduce the diffusion of polysulfide so as to reduce the shuttle flying effect. These advantages can effectively solve the problems of the positive electrode of the lithium-sulfur battery.

The super capacitor is used as a renewable green energy storage device and has wide application in the fields of new energy automobiles, electronics, national defense and the like. The main problems of the current capacitor are low energy and power density and high production cost. Carbon materials are currently the most widely used and most effective electrode materials in the capacitor field. Mainly comprises graphene, carbon nanotubes, activated carbon and various nano-structure carbon materials. In recent years, carbon nanotubes and graphene are widely used in the field of capacitors, but are limited by the cost, and large-scale production is difficult to realize. There are many methods for solving the problem of low energy and power density, and effective methods include adjusting the pore structure and doping with hetero atoms. The material with micropores and mesopores can obviously improve the performance of the capacitor, the micropores are used for storing energy, and the mesopores can provide a channel for rapid ion transfer. Hetero atoms (such as N, O, S, B and the like) can change the surface properties of the carbon material, so that the capacitance of the capacitor is improved. The nanometer microsphere with a cavity structure synthesized by the invention can generate a multilevel pore structure nanometer carbon sphere with a cavity structure after calcination and activation treatment, and the obtained microsphere has various heteroatoms. Has wide application prospect in the field of capacitors.

At present, a method for preparing nitrogen-containing nano-microspheres from melamine or a mixture of melamine and resorcinol is available, and nitrogen-containing nano-carbon spheres can be obtained by further roasting. The specific methods include a water bath heating method and a hydrothermal method. The water bath heating method firstly prepares prepolymer, namely the product of N-methylolation of melamine and formaldehyde, which is called prepolymer, and then the prepolymer is further polycondensed under acidic condition to prepare the melamine formaldehyde resin microspheres. Preparing a prepolymer by a hydrothermal method, and polymerizing the prepolymer under a hydrothermal condition to obtain melamine formaldehyde resin microspheres; higher reaction temperature (70-300 ℃) and longer reaction time (6-72h) are needed, and the realization of large-scale industrial application is difficult. The microspheres prepared by the invention can be produced in large scale at normal temperature, and are easy to realize industrial application.

Disclosure of Invention

The invention aims to provide a preparation method of polymer nano-microspheres with cavity structures, which are free of templates, have room temperature conditions, are quick in reaction and contain doped heteroatoms; the method is characterized in that under the stirring condition, m-phenylenediamine, p-phenylenediamine, o-phenylenediamine, 2, 6-diaminopyridine, 1, 5-diaminonaphthalene or 1, 8-diaminonaphthalene and melamine are used as raw materials at a mild reaction temperature of 10-50 ℃, in the presence of anthranilic acid, p-aminobenzoic acid, m-aminobenzenesulfonic acid, o-aminobenzenesulfonic acid, p-aminobenzenesulfonic acid, 3, 5-diaminobenzoic acid or 2, 4-diaminobenzenesulfonic acid, in a mixed solution of acetone and water or a pure acetone system, the self reaction kinetics of reactants are different to form a coated nano microsphere, and then a proper solvent is adopted for soaking or washing to selectively remove internal components to form a cavity inside, thereby forming the nano microsphere with a core-shell structure or a hollow structure. The nano microsphere product prepared by the method has the advantages of controllable size and appearance, uniform granularity, uniform dispersion, high yield, uniform heteroatom doping and enhanced material toughness.

Specifically, the preparation method of the heteroatom-doped polymer nano-microsphere with the cavity structure comprises the following steps:

(1) at 10-50 deg.C; one or more of m-phenylenediamine, p-phenylenediamine, o-phenylenediamine, 2, 6-diaminopyridine, 1, 5-diaminonaphthalene or 1, 8-diaminonaphthalene;

with melamine;

and one or more of o-aminobenzoic acid, p-aminobenzoic acid, m-aminobenzenesulfonic acid, o-aminobenzenesulfonic acid, p-aminobenzenesulfonic acid, 3, 5-diaminobenzoic acid and 2, 4-diaminobenzenesulfonic acid are dissolved in the solvent;

the solvent is selected from one or a mixture of more of acetone, water methanol, ethanol, dimethyl sulfoxide, N-N-dimethylformamide, tetrahydrofuran, glycol and N-propanol;

(2) adding ammonia water, sodium bicarbonate, sodium carbonate, sodium hydroxide, potassium carbonate or potassium bicarbonate solution into the system, uniformly stirring, and adjusting the pH value of the system to 8-9;

(3) adding formaldehyde, glyoxal, malonaldehyde, succinaldehyde, glutaraldehyde or adipaldehyde into the solution at room temperature, and stirring for reaction to obtain the polymer nano-microsphere.

(4) And soaking or washing the obtained nano microspheres in methanol, ethanol, formaldehyde or formic acid and a mixed solution of the methanol, the ethanol, the formaldehyde or the formic acid to obtain the nano microspheres with the cavity structures.

Wherein, the concentration of one or more of o-aminobenzoic acid, p-aminobenzoic acid, m-aminobenzenesulfonic acid, o-aminobenzenesulfonic acid, p-aminobenzenesulfonic acid, 3, 5-diaminobenzoic acid or 2, 4-diaminobenzenesulfonic acid in the step (1) in the solution formed in the step (1) is 0.002-1.0 mol/L. One or more of m-phenylenediamine, p-phenylenediamine, o-phenylenediamine, 2, 6-diaminopyridine, 1, 5-diaminonaphthalene, 1, 8-diaminonaphthalene or melamine is/are added into the solution in the step (1) to form a solution with the concentration of 0.002-1.0 mol/L.

Wherein the temperature in the step (1) is 10-50 ℃, and the room temperature is preferably 25 DEG C

Adding ammonia water, sodium bicarbonate, sodium carbonate, sodium hydroxide, potassium carbonate or potassium bicarbonate solution in the step (2), and stirring uniformly (about 0.5 hour) or forming a clear and transparent solution in a dropwise manner for about 1-6 hours;

and (3) adding the aldehyde in the step (3) in a dropwise manner, wherein the using amount of the aldehyde is 5-15 times of the aldehyde amount relative to the arylamine.

In the step (3), preferably under stirring, the solution changes from clear to turbid with time; keeping stirring and polycondensation reaction for 1-6 hours, centrifuging the product at 6000 rpm, and soaking the product in different solvents to form a cavity structure. Drying the centrifuged product for 6 hours at 100 ℃ to obtain polymer nano microspheres with cavity structures, which have uniform particle size, controllable morphology and good dispersibility;

further, in the technical scheme, in the step (3), the aldehyde is added and then the mixture is stirred to react for 1-12 hours.

The method adopts basic materials such as melamine, arylamine and aldehyde as raw materials, adopts acetone and water as a reaction system, adds ammonia water to adjust the pH value of the reaction, is favorable for regulating and controlling the uniformity and the shape of the polymer nano microspheres, and is favorable for quickly forming the nano microspheres and controlling the shape of the polymer nano microspheres by adding the amino aromatic derivative. The concentration of m-phenylenediamine, p-phenylenediamine, o-phenylenediamine, 2, 6-diaminopyridine, 1, 5-diaminonaphthalene, 1, 8-diaminonaphthalene, melamine, anthranilic acid, p-aminobenzoic acid, m-aminobenzenesulfonic acid, o-aminobenzenesulfonic acid, p-aminobenzenesulfonic acid, 3, 5-diaminobenzoic acid or 2, 4-diaminobenzenesulfonic acid, and ammonia water in the system are mutually restricted. The regulation and control of the grain diameter, the shell thickness and the core size of the polymer nano microsphere can be realized by changing the molar ratio of the amino aromatic derivative to the arylamine, the molar ratio of the arylamine to the aldehyde, the concentration of the arylamine, different ammonia water addition amounts and different reaction temperatures (10-50 ℃) in the system.

The nitrogen content of the heteroatom-doped polymer nano-microspheres obtained by preparing the heteroatom-doped nano-microspheres with cavity structures by a template-free method is 20-80 wt%, and the content is adjustable. The diameter of the nano microsphere is 100nm-1 μm, the particle size is uniform, the distribution of N, S heteroatoms is uniform, the size is adjustable, and the dispersibility is good.

The nitrogen-sulfur-containing polymer nano-microsphere is roasted under the inert gas atmosphere to obtain the nitrogen-sulfur-containing carbon nano-microsphere. The diameter of the nano microsphere is 100nm-1 μm, the particle size is uniform, the distribution of hetero atoms is uniform, the size is adjustable, and the dispersibility is good.

The method overcomes the defects of complex operation, harsh reaction conditions, difficult template removal and the like in the traditional hard template method for preparing the microspheres with the cavity structures. The method overcomes the defects that the soft template method is limited by limited available template agents, and has fussy operation and long flow, and the novel synthetic method adopted by the invention has simple operation, easy amplification and easy realization of industrialization.

The invention provides a positive electrode material for a lithium-sulfur battery, which is prepared by the method and has a cavity structure, and solves the problems of the positive electrode of the lithium-sulfur battery.

The invention provides a method for using the carbon nanospheres with the cavity structure obtained by the method for capacitor electrode materials, which is used for solving the problems of low energy and power density, high production cost and the like of capacitors.

The invention abandons the traditional synthesis method of hard template and soft template, adopts a template-free method, utilizes the difference of the self reaction kinetics performance of reactants to form a nano microsphere with a coating structure in one step, and then uses a simple solvent to leach out internal products to form a cavity, thereby avoiding the complex template method process, simplifying the synthesis of the polymer nano microsphere with a core-shell or hollow structure, realizing large-scale production and providing more possibility for the application of the nano microsphere with a special structure.

Has the advantages that:

1. the method adopts a brand-new process route, and can be produced at a mild operation temperature and room temperature; the relatively harsh hydrothermal reaction condition of 70-100 ℃ used in the traditional process is avoided; is especially suitable for being rapidly carried out at normal temperature (15-25 ℃) and is more beneficial to popularization and application.

2. The invention departs from the traditional hard template and soft template method, and can obtain the polymer microsphere with the core-shell structure by simple solvent leaching or washing operation by utilizing the difference of the reaction rates of two reactants.

3. The method has the advantages of simple process, easy operation and high yield, and can obtain the core-shell structure nano-microspheres with controllable sizes and shapes by controlling the ratio of the amino aromatic derivatives to the arylamine, the ratio of the arylamine to the aldehyde, the concentration of the arylamine, different ammonia water addition amounts and different reaction temperatures (10-50 ℃) according to use requirements.

4. The method disclosed by the invention is quick in reaction, the product is generated within a few minutes after the step (3) of dripping the aldehyde, under the stirring condition, the solution is changed from clarification to turbidity along with the prolonging of time, the products are gradually increased, and the polymer nano microspheres are centrifugally taken out until the reaction is finished. The nano polymer microsphere with the cavity structure can be obtained by soaking or washing with a specific solvent.

5. The hollow carbon spheres synthesized by the method are subjected to different amounts of KOH and K₂CO₃Activating (800 deg.C for 1h), compounding with sulfur (sulfur content 50% -80%), and treating with K₂CO₃Treatment (K)₂CO₃Sample 3: 1-80% of sulfur content), the first discharge energy reaches 1176mAh g^-1After 100 times of circulation under the current density of 0.2C, the battery can still maintain 670mAh g^-1. The first discharge energy of the sample reaches 1172mAh g after KOH treatment (the content of sulfur is 1: 80 percent)^-1After 180 times of circulation under the current density of 0.2C, the battery can still maintain 602mAh g^-1. The first discharge energy of KOH treatment (KOH: sample 0.75: 1-80% of sulfur content) reached 1334mAh g^-1After 300 times of circulation at the current density of 1C, the battery can still maintain 560mAhg^-1。

Drawings

FIG. 1: SEM image of the nano-microsphere of 3, 5-diaminobenzoic acid reacting in water as solvent at room temperature;

FIG. 2: SEM and TEM images of the nano-microspheres obtained by reacting 3, 5-diaminobenzoic acid in acetone as a solvent at room temperature;

FIG. 3: SEM image of nano microsphere of 3, 5-diaminobenzoic acid reacting in acetone as solvent at room temperature with 0.4ml ammonia water;

FIG. 4: changing the amount SEM image of the 3, 5-diaminobenzoic acid by the nano-microspheres which react at room temperature by taking acetone as a solvent;

FIG. 5: washing a sample SEM picture of the nano microspheres subjected to reaction of 3, 5-diaminobenzoic acid at room temperature by using ethanol in acetone as a solvent;

FIG. 6: TEM image of 3, 5-diaminobenzoic acid washed nano-microsphere with ethanol in acetone as solvent at room temperature;

FIG. 7: washing the 3, 5-diaminobenzoic acid nano-microspheres with ethanol at room temperature by taking acetone as a solvent, and changing the amount of m-phenylenediamine in an SEM picture;

FIG. 8: washing the 3, 5-diaminobenzoic acid nano-microspheres with ethanol at room temperature by taking acetone as a solvent, and changing the amount of the metamelamine in the SEM image;

FIG. 9: changing the amount SEM image of the 3, 5-diaminobenzoic acid after washing the nano-microsphere by ethanol in acetone as a solvent at room temperature;

FIG. 10: washing the 3, 5-diaminobenzoic acid nano-microspheres with ethanol at room temperature by taking acetone as a solvent, and changing the ammonia water amount SEM picture;

FIG. 11: SEM images of the nano-microsphere with the mixed solvent of different acetone and water by taking the mixed solution of 3, 5-diaminobenzoic acid and acetone and water as the solvent at room temperature;

FIG. 12: TEM image of washing nano-microsphere with pure ethanol by using 3, 5-diaminobenzoic acid and acetone-water mixed solution as solvent at room temperature;

FIG. 13: SEM pictures of washing the nano-microspheres with different solvents by using a mixed solution of 3, 5-diaminobenzoic acid and acetone water as the solvent at room temperature;

FIG. 14: TEM image of washing nano-microsphere with methanol at room temperature with 3, 5-diaminobenzoic acid in acetone-water mixed solution as solvent;

FIG. 15: washing nano microspheres with 3, 5-diaminobenzoic acid as a solvent in an acetone-water mixed solution at room temperature by using methanol to obtain SEM images with different concentrations;

FIG. 16: washing nano microspheres with 3, 5-diaminobenzoic acid in acetone-water mixed solution as solvent at room temperature with methanol to obtain SEM images and TEM images with different ammonia water amounts;

FIG. 17: SEM images of different melamine amounts of the nano-microspheres washed by methanol at room temperature by using 3, 5-diaminobenzoic acid and acetone-water mixed solution as a solvent;

FIG. 18: SEM pictures of different amounts of m-phenylenediamine are washed by methanol by the nano-microsphere with 3, 5-diaminobenzoic acid as a solvent in acetone-water mixed solution at room temperature;

FIG. 19: washing 2, 4-diaminobenzene sulfonic acid in acetone solvent nano-microsphere with 20% ethanol at room temperature, SEM, TEM picture;

FIG. 20: washing the nano-microspheres with methanol at room temperature for 24h by using 3, 5-diaminobenzoic acid and acetone-water mixed solution as a solvent;

FIG. 21: washing and calcining the nano-microspheres with methanol at room temperature by using 3, 5-diaminobenzoic acid and acetone-water mixed solution as a solvent, and taking a carbon sphere SEM (scanning electron microscope) and a TEM (transmission electron microscope) image;

FIG. 22: under the condition of reaction amplification six times of room temperature, 3, 5-diaminobenzoic acid is used as a solvent, and nano microspheres are washed and calcined by formaldehyde to obtain carbon spheres SEM (scanning electron microscope) and TEM (transmission electron microscope) images;

FIG. 23: SEM image of 3, 5-diaminobenzoic acid in acetone-water mixed solution as solvent nano microsphere at room temperature by replacing ammonia water with sodium bicarbonate;

FIG. 24: SEM picture of replacing formaldehyde with glutaraldehyde by using 3, 5-diaminobenzoic acid as solvent nano microsphere at room temperature and in acetone-water mixed solution;

FIG. 25: by K₂CO₃Activation treatment (K)₂CO₃Sample 3: 1-80%) of sulfur, and circulating the battery for 100 times at a current density of 0.2C;

FIG. 26: the cells were made up with KOH activation treatment (KOH: sample 1: 1 sulfur content-80%) and cycled 180 times at a current density of 0.2C;

FIG. 27 is a schematic view showing: the cells were made up with KOH activation treatment (KOH: sample 0.75: 1-80% sulfur content) and cycled 300 times at a current density of 1C;

Detailed Description

The following non-limiting examples will allow one of ordinary skill in the art to more fully understand the present invention, but are not intended to limit the invention in any way.

The test methods described in the following examples are all conventional methods unless otherwise specified; the reagents and materials are commercially available, unless otherwise specified.

Example 1

0.063g (0.0005mol) of melamine, 0.054g (0.0005mol) of m-phenylenediamine, 0.047g (0.0003mol) of 3, 5-diaminobenzoic acid were dissolved in 50mL of water, and 0.2mL of aqueous ammonia was added dropwise thereto, and the mixture was stirred at 25 ℃ and 500rpm until the solution became a brown suspension. 2mL of an aqueous formaldehyde solution was added, and after about 40sec, the liquid turned turbid from clear. The temperature was maintained and stirring was carried out at 500rpm for 2 h. After the reaction is finished, centrifuging, washing by using 20% ethanol solution, drying, and observing by using an electron microscope to obtain the nitrogen content of the nitrogen-containing polymer nano microsphere of about 30%. The particle size 116nm is shown in FIG. 1.

Example 2

0.126g (0.001mol) of melamine, 0.108g (0.001mol) of m-phenylenediamine, and 0.047g (0.0003mol) of 3, 5-diaminobenzoic acid were dissolved in 50mL of acetone, and 0.2mL of aqueous ammonia was added dropwise thereto, followed by stirring at 25 ℃ and 500rpm until the solution became a brown suspension. 2mL of an aqueous formaldehyde solution was added, and after about 3sec, the liquid turned turbid from clear. The temperature was maintained and stirring was carried out at 500rpm for 2 h. After the reaction is finished, centrifuging, washing by using 20% ethanol solution, drying, and observing by using an electron microscope to obtain the nitrogen content of the nitrogen-containing polymer nano microsphere of about 40%. The particle size 547nm is shown in FIG. 2.

Example 3

0.126g (0.001mol) of melamine, (0.001mol) of m-phenylenediamine, 0.047g (0.0003mol) of 3, 5-diaminobenzoic acid are dissolved in 50mL of acetone, ammonia is added dropwise, and the solution is stirred at a temperature of 25 ℃ and a rotation speed of 500rpm until the solution becomes a brown suspension. 2mL of an aqueous formaldehyde solution was added, and after about 7sec, the liquid turned turbid from clear. The temperature was maintained and stirring was carried out at 500rpm for 2 h. After the reaction is finished, centrifuging, washing by using 20% ethanol solution, drying, and observing by using an electron microscope to obtain the nitrogen content of the nitrogen-containing polymer nano microsphere of about 40%. The amount of ammonia (0.4mL) was varied as shown in FIG. 3.

Example 4

0.126g (0.001mol) of melamine, 0.108g (0.001mol) of m-phenylenediamine and 3, 5-diaminobenzoic acid are dissolved in 50mL of acetone, 0.2mL of ammonia water is added dropwise, and the solution is stirred at 25 ℃ and 500rpm until the solution becomes a brown suspension. 2mL of an aqueous formaldehyde solution was added, and after about 3sec, the liquid turned turbid from clear. The temperature was maintained and stirring was carried out at 500rpm for 2 h. After the reaction is finished, centrifuging, washing by using 20% ethanol solution, drying, and observing by using an electron microscope to obtain the nitrogen content of the nitrogen-containing polymer nano microsphere of about 40%. The amount of 3, 5-diaminobenzoic acid was varied (0.00060mol) as shown in FIG. 4.

Example 5

0.126g (0.001mol) of melamine, 0.108g (0.001mol) of m-phenylenediamine, and 0.047g (0.0003mol) of 3, 5-diaminobenzoic acid were dissolved in 50mL of acetone, and 0.2mL of aqueous ammonia was added dropwise thereto, followed by stirring at 25 ℃ and 500rpm until the solution became a brown suspension. 2mL of an aqueous formaldehyde solution was added, and after about 3sec, the liquid turned turbid from clear. The temperature was maintained and stirring was carried out at 500rpm for 2 h. After the reaction is finished, centrifuging, washing by using a solvent, drying, and observing by using an electron microscope to obtain the nitrogen content of the nitrogen-containing polymer nano microsphere of about 40%. Washing with ethanol is shown in FIG. 5.

Example 6

0.126g (0.001mol) of melamine, 0.108g (0.001mol) of m-phenylenediamine, and 0.047g (0.0003mol) of 3, 5-diaminobenzoic acid were dissolved in 50mL of acetone, and 0.2mL of aqueous ammonia was added dropwise thereto, followed by stirring at 25 ℃ and 500rpm until the solution became a brown suspension. 2mL of an aqueous formaldehyde solution was added, and after about 3sec, the liquid turned turbid from clear. The temperature was maintained and stirring was carried out at 500rpm for 2 h. After the reaction is finished, centrifuging, washing with ethanol, drying, and observing by an electron microscope to obtain the nitrogen content of the nitrogen-containing polymer nano microsphere of about 30%. As shown in the TEM image of fig. 6.

Example 7

0.126g (0.001mol) of melamine, various amounts of m-phenylenediamine, 0.047g (0.0003mol) of 3, 5-diaminobenzoic acid are dissolved in 50mL of acetone, 0.2mL of ammonia water is added dropwise, and the solution is stirred at 25 ℃ and 500rpm until it becomes a brown suspension. 2mL of an aqueous formaldehyde solution was added, and after about 5sec, the liquid turned turbid from clear. The temperature was maintained and stirring was carried out at 500rpm for 2 h. After the reaction is finished, centrifuging, washing with ethanol, drying, and observing by an electron microscope to obtain the nitrogen content of the nitrogen-containing polymer nano microsphere of about 50%. The amount of m-phenylenediamine varied (0.0025mol) is shown in FIG. 7.

Example 8

Melamine, 0.126g (0.001mol) m-phenylenediamine, 0.047g (0.0003mol)3, 5-diaminobenzoic acid were dissolved in 50mL acetone, 0.2mL ammonia was added dropwise, and the mixture was stirred at 25 ℃ and 500rpm until the solution became a brown suspension. 2mL of an aqueous formaldehyde solution was added, and after about 5sec, the liquid turned turbid from clear. The temperature was maintained and stirring was carried out at 500rpm for 2 h. After the reaction is finished, centrifuging, washing with ethanol, drying, and observing by an electron microscope to obtain the nitrogen content of the nitrogen-containing polymer nano microsphere of about 50%. The amount of melamine was varied (0.002mol) as shown in FIG. 8.

Example 9

0.126g (0.001mol) of melamine, 0.108g (0.001mol) of m-phenylenediamine and 3, 5-diaminobenzoic acid are dissolved in 50mL of acetone, 0.2mL of ammonia water is added dropwise, and the solution is stirred at 25 ℃ and 500rpm until the solution becomes a brown suspension. 2mL of an aqueous formaldehyde solution was added, and after about 3sec, the liquid turned turbid from clear. The temperature was maintained and stirring was carried out at 500rpm for 2 h. After the reaction is finished, centrifuging, washing by using a pure ethanol solution, drying, and observing by using an electron microscope to obtain the nitrogen content of the nitrogen-containing polymer nano microsphere of about 40%. The amount of 3, 5-diaminobenzoic acid (0.00015mol) is shown in FIG. 9.

Example 10

0.126g (0.001mol) of melamine, (0.001mol) of m-phenylenediamine, 0.047g (0.0003mol) of 3, 5-diaminobenzoic acid are dissolved in 50mL of acetone, ammonia is added dropwise, and the solution is stirred at a temperature of 25 ℃ and a rotation speed of 500rpm until the solution becomes a brown suspension. 2mL of an aqueous formaldehyde solution was added, and after about 7sec, the liquid turned turbid from clear. The temperature was maintained and stirring was carried out at 500rpm for 2 h. After the reaction is finished, centrifuging, washing by using 20% ethanol solution, drying, and observing by using an electron microscope to obtain the nitrogen content of the nitrogen-containing polymer nano microsphere of about 40%. The amount of ammonia (0.8ml) was varied as shown in FIG. 10.

Example 11

0.126g (0.001mol) of melamine, 0.108g (0.001mol) of m-phenylenediamine and 0.047g (0.0003mol) of 3, 5-diaminobenzoic acid are dissolved in a mixed solvent of acetone and water with different water contents, 0.2mL of ammonia water is added dropwise, and the solution is stirred at the temperature of 25 ℃ and the rotating speed of 500rpm until the solution becomes a brown suspension. 2mL of an aqueous formaldehyde solution was added, and after about 6sec, the liquid turned turbid from clear. The temperature was maintained and stirring was carried out at 500rpm for 2 h. After the reaction is finished, centrifuging, washing by using 20% ethanol solution, drying, and observing by using an electron microscope to obtain the nitrogen content of the nitrogen-containing polymer nano microsphere of about 40%. The volume of acetone and the volume of water were (45mL, 5mL), as shown in FIG. 11.

Example 12

0.126g (0.001mol) of melamine, 0.108g (0.001mol) of m-phenylenediamine, 0.047g (0.0003mol) of 3, 5-diaminobenzoic acid are dissolved in 35mL of acetone and 5mL of water, 0.2mL of ammonia water is added dropwise thereto, and the mixture is stirred at a temperature of 25 ℃ and a rotation speed of 500rpm until the solution becomes a brown suspension. 2mL of an aqueous formaldehyde solution was added, and after about 6sec, the liquid turned turbid from clear. The temperature was maintained and stirring was carried out at 500rpm for 2 h. After the reaction is finished, centrifuging, washing twice with a pure ethanol solution, drying, and observing by an electron microscope to obtain the nitrogen content of the nitrogen-containing polymer nano microsphere of about 40%. As shown in fig. 12 TEM.

Example 13

0.126g (0.0005mol) of melamine, 0.108g (0.001mol) of m-phenylenediamine, 0.047g (0.0003mol) of 3, 5-diaminobenzoic acid are dissolved in 35mL of acetone and 5mL of water, 0.2mL of ammonia water is added dropwise thereto, and the mixture is stirred at a temperature of 25 ℃ and a rotation speed of 500rpm until the solution becomes a brown suspension. 2mL of an aqueous formaldehyde solution was added, and after about 5sec, the liquid turned turbid from clear. The temperature was maintained and stirring was carried out at 500rpm for 2 h. After the reaction is finished, centrifuging, soaking the sample for 1h by using different solvents, drying, and observing by using an electron microscope to obtain the nitrogen content of the nitrogen-containing polymer nano microsphere of about 30 percent. The solvent used is methanol SEM as shown in FIG. 13.

Example 14

0.126g (0.001mol) of melamine, 0.108g (0.001mol) of m-phenylenediamine, 0.047g (0.0003mol) of 3, 5-diaminobenzoic acid were dissolved in 35mL of acetone and 5mL of water, and 0.2mL of ammonia water was added dropwise thereto, followed by stirring at 25 ℃ and 500rpm until the solution became a brown suspension. 2mL of an aqueous formaldehyde solution was added, and after about 5sec, the liquid turned turbid from clear. The temperature was maintained and stirring was carried out at 500rpm for 2 h. After the reaction is finished, centrifuging, soaking the sample for 1h by using methanol, drying, and observing by using an electron microscope to obtain the nitrogen content of the nitrogen-containing polymer nano microsphere of about 40%. The TEM is shown in FIG. 14.

Example 15

0.063g (0.0005mol)0.126g (0.001mol) of melamine, 0.054g (0.0005mol)0.108g (0.001mol) of m-phenylenediamine, 0.0235g (0.00015mol)0.047g (0.0003mol) of 3, 5-diaminobenzoic acid were dissolved in 35mL of acetone and 5mL of water, 0.2mL of ammonia water was added dropwise thereto, and the mixture was stirred at 25 ℃ and 500rpm until the solution became a brown suspension. 2mL of an aqueous formaldehyde solution was added, and after about 3sec, the liquid turned turbid from clear. The temperature was maintained and stirring was carried out at 500rpm for 2 h. After the reaction is finished, centrifuging, soaking the sample in methanol for 30min, drying, and observing by an electron microscope to obtain the nitrogen content of the nitrogen-containing polymer nano microsphere of about 40%. Total reactant concentration (0.00115mol), (0.0023mol) SEM, TEM image 15.

Example 16

0.126g (0.001mol) of melamine, 0.108g (0.001mol) of m-phenylenediamine, 0.047g (0.0003mol) of 3, 5-diaminobenzoic acid are dissolved in 35mL of acetone and 5mL of water, ammonia water is added dropwise, and the solution is stirred at a temperature of 25 ℃ and a rotation speed of 500rpm until the solution becomes a brown suspension. 2mL of an aqueous formaldehyde solution was added, and after about 5sec, the liquid turned turbid from clear. The temperature was maintained and stirring was carried out at 500rpm for 2 h. After the reaction is finished, centrifuging, soaking the sample in methanol for 30min, drying, and observing by an electron microscope to obtain the nitrogen-containing polymer nano-microsphere with the nitrogen content of about 40%. Different amounts of ammonia (0mL), (0.1mL), (0.4mL) were added as shown in FIG. 16SEM, TEM.

Example 17

Melamine, 0.108g (0.001mol) m-phenylenediamine, 0.047g (0.0003mol)3, 5-diaminobenzoic acid were dissolved in 35mL acetone and 5mL water, 0.2mL ammonia was added dropwise, and the mixture was stirred at 25 ℃ and 500rpm until the solution became a brown suspension. 2mL of an aqueous formaldehyde solution was added, and after about 5sec, the liquid turned turbid from clear. The temperature was maintained and stirring was carried out at 500rpm for 2 h. After the reaction is finished, centrifuging, soaking the sample in methanol for 30min, drying, and observing by an electron microscope to obtain the nitrogen-containing polymer nano-microsphere with the nitrogen contents of about 25 percent and 45 percent respectively. The amounts of melamine (0.00025mol) and (0.0010mol) were varied as shown in FIG. 17.

Example 18

0.126g (0.001mol) of melamine, m-phenylenediamine, 0.047g (0.0003mol) of 3, 5-diaminobenzoic acid are dissolved in 35mL of acetone and 5mL of water, 0.2mL of ammonia water is added dropwise, and the solution is stirred at a temperature of 25 ℃ and a rotation speed of 500rpm until the solution becomes a brown suspension. 2mL of an aqueous formaldehyde solution was added, and after about 5sec, the liquid turned turbid from clear. The temperature was maintained and stirring was carried out at 500rpm for 2 h. After the reaction is finished, centrifuging, soaking the sample in methanol for 30min, drying, and observing by an electron microscope to obtain the nitrogen content of the nitrogen-containing polymer nano microsphere of about 40% and 25% respectively. The amounts (0.00025mol) and (0.0010mol) of m-phenylenediamine were varied as shown in FIG. 18.

Example 19

0.126g (0.001mol) of melamine, 0.108g (0.001mol) of m-phenylenediamine, 0.058g (0.0003mol) of 2, 4-diaminobenzene sulfonic acid were dissolved in 50mL of acetone, 0.2mL of ammonia water was added dropwise thereto, and the mixture was stirred at 25 ℃ and 500rpm until the solution became a brown suspension. 2mL of an aqueous formaldehyde solution was added, and after about 10sec, the liquid turned turbid from clear. The temperature was maintained and stirring was carried out at 500rpm for 2 h. After the reaction is finished, centrifuging, washing by using 20% ethanol solution, drying, and observing by using an electron microscope to obtain the nitrogen content of the nitrogen-containing polymer nano microsphere of about 40%. As shown in fig. 19SEM, TEM.

Example 20

0.126g (0.001mol) of melamine, 0.108g (0.001mol) of m-phenylenediamine, 0.047g (0.0003mol) of 3, 5-diaminobenzoic acid are dissolved in 35mL of acetone and 5mL of water, 0.2mL of ammonia water is added dropwise thereto, and the mixture is stirred at a temperature of 25 ℃ and a rotation speed of 500rpm until the solution becomes a brown suspension. 2mL of an aqueous formaldehyde solution was added, and after about 5sec, the liquid turned turbid from clear. The temperature was maintained and stirring was carried out at 500rpm for 2 h. After the reaction is finished, centrifuging, soaking in methanol for 24h, drying, and observing by an electron microscope to obtain the nitrogen content of the nitrogen-containing polymer nano microsphere of about 40%. The TEM is shown in FIG. 20.

Example 21

0.126g (0.001mol) of melamine, 0.108g (0.001mol) of m-phenylenediamine, 0.047g (0.0003mol) of 3, 5-diaminobenzoic acid are dissolved in 35mL of acetone and 5mL of water, 0.2mL of ammonia water is added dropwise thereto, and the mixture is stirred at a temperature of 25 ℃ and a rotation speed of 500rpm until the solution becomes a brown suspension. 2mL of an aqueous formaldehyde solution was added, and after about 5sec, the liquid turned turbid from clear. The temperature was maintained and stirring was carried out at 500rpm for 2 h. After the reaction is finished, centrifuging, soaking in methanol for 1h, drying, and observing by an electron microscope to obtain the nitrogen content of the nitrogen-containing polymer nano microsphere of about 40%. And (3) obtaining an SEM (scanning electron microscope) with the nitrogen content of about 20% of the carbon spheres with the yellow shell structures through calcination at 800 ℃, wherein the TEM is shown in a figure 21.

Example 22

0.756g (0.006mol) of melamine, 0.648g (0.006mol) of m-phenylenediamine, 0.282g (0.0018mol) of 3, 5-diaminobenzoic acid were dissolved in 210mL of acetone and 30mL of water, and 1.2mL of ammonia water was added dropwise thereto, and the mixture was stirred at 25 ℃ and 500rpm until the solution became a brown suspension. 12mL of an aqueous formaldehyde solution was added, and after about 5sec, the liquid turned turbid from clear. The temperature was maintained and stirring was carried out at 500rpm for 2 h. After the reaction is finished, centrifuging, soaking for 1h in formaldehyde, drying, and observing by an electron microscope to obtain the nitrogen content of the nitrogen-containing polymer nano microsphere of about 30%. And (3) obtaining an SEM (scanning electron microscope) with the nitrogen content of the hollow-structure nano carbon spheres of about 20% by calcining at 700 ℃, wherein the TEM is shown in a figure 22.

Example 23

0.126g (0.001mol) of melamine, 0.108g (0.001mol) of m-phenylenediamine, 0.047g (0.0003mol) of 3, 5-diaminobenzoic acid are dissolved in 35mL of acetone and 5mL of water, 0.26g (0.003mol) of sodium bicarbonate is added, and the mixture is stirred at 25 ℃ and 500rpm until the solution is a brown suspension. 2mL of an aqueous formaldehyde solution was added, and after about 5sec, the liquid turned turbid from clear. The temperature was maintained and stirring was carried out at 500rpm for 2 h. After the reaction is finished, centrifuging, soaking for 1h in formaldehyde, drying, and observing by an electron microscope to obtain the nitrogen content of the nitrogen-containing polymer nano microsphere of about 40%. The SEM is shown in FIG. 23.

Example 24

0.126g (0.001mol) of melamine, 0.108g (0.001mol) of m-phenylenediamine, 0.047g (0.0003mol) of 3, 5-diaminobenzoic acid are dissolved in 35mL of acetone and 5mL of water, 0.2mL of ammonia water is added dropwise thereto, and the mixture is stirred at a temperature of 25 ℃ and a rotation speed of 500rpm until the solution becomes a brown suspension. 2mL of an aqueous glutaraldehyde solution was added, and after about 5sec, the liquid turned turbid from clear. The temperature was maintained and stirring was carried out at 500rpm for 2 h. After the reaction is finished, centrifuging, soaking for 1h in formaldehyde, drying, and observing by an electron microscope to obtain the nitrogen content of the nitrogen-containing polymer nano microsphere of about 40%. The SEM is shown in FIG. 24.

Example 25

0.126g (0.001mol) of melamine, (0.001mol) of o-phenylenediamine, 0.047g (0.0003mol) of 3, 5-diaminobenzoic acid are dissolved in 50mL of acetone, 0.2mL of ammonia water is added dropwise, and the solution is stirred at 25 ℃ and 500rpm until a brown suspension is formed. 2mL of an aqueous formaldehyde solution was added, and after about 7sec, the liquid turned turbid from clear. The temperature was maintained and stirring was carried out at 500rpm for 2 h. After the reaction is finished, centrifuging, washing by using 20% ethanol solution, drying, and observing by using an electron microscope to obtain the nitrogen content of the nitrogen-containing polymer nano microsphere of about 40%.

Example 26

0.126g (0.001mol) of melamine, (0.001mol) of p-phenylenediamine, 0.047g (0.0003mol) of 3, 5-diaminobenzoic acid are dissolved in 50mL of acetone, 0.2mL of ammonia water is added dropwise, and the solution is stirred at 25 ℃ and 500rpm until the solution becomes a brown suspension. 2mL of an aqueous formaldehyde solution was added, and after about 7sec, the liquid turned turbid from clear. The temperature was maintained and stirring was carried out at 500rpm for 2 h. After the reaction is finished, centrifuging, washing by using 20% ethanol solution, drying, and observing by using an electron microscope to obtain the nitrogen content of the nitrogen-containing polymer nano microsphere of about 40%.

Example 27

0.126g (0.001mol) of melamine, (0.001mol) of m-phenylenediamine, 0.047g (0.0003mol) of 3, 5-diaminobenzoic acid are dissolved in 50mL of methanol, 0.2mL of ammonia water is added dropwise, and the solution is stirred at 25 ℃ and 500rpm until the solution becomes a brown suspension. 2mL of an aqueous formaldehyde solution was added, and after about 7sec, the liquid turned turbid from clear. The temperature was maintained and stirring was carried out at 500rpm for 2 h. After the reaction is finished, centrifuging, washing by using 20% ethanol solution, drying, and observing by using an electron microscope to obtain the nitrogen content of the nitrogen-containing polymer nano microsphere of about 40%.

Example 28

0.126g (0.001mol) of melamine, (0.001mol) of m-phenylenediamine, 0.047g (0.0003mol) of 3, 5-diaminobenzoic acid are dissolved in 50mL of dimethyl sulfoxide, 0.2mL of ammonia water is added dropwise, and the solution is stirred at 25 ℃ and 500rpm until the solution becomes a brown suspension. 2mL of an aqueous formaldehyde solution was added, and after about 7sec, the liquid turned turbid from clear. The temperature was maintained and stirring was carried out at 500rpm for 2 h. After the reaction is finished, centrifuging, washing by using 20% ethanol solution, drying, and observing by using an electron microscope to obtain the nitrogen content of the nitrogen-containing polymer nano microsphere of about 40%.

Example 29

0.126g (0.001mol) of melamine, (0.001mol) of m-phenylenediamine, 0.047g (0.0003mol) of 3, 5-diaminobenzoic acid are dissolved in 50mL of N, N-dimethylformamide, 0.2mL of ammonia water is added dropwise, and the solution is stirred at 25 ℃ and 500rpm until it becomes a brown suspension. 2mL of an aqueous formaldehyde solution was added, and after about 7sec, the liquid turned turbid from clear. The temperature was maintained and stirring was carried out at 500rpm for 2 h. After the reaction is finished, centrifuging, washing by using 20% ethanol solution, drying, and observing by using an electron microscope to obtain the nitrogen content of the nitrogen-containing polymer nano microsphere of about 40%.

Example 30

0.126g (0.001mol) of melamine, (0.001mol) of m-phenylenediamine, 0.047g (0.0003mol) of 3, 5-diaminobenzoic acid are dissolved in 50mL of ethanol, 0.2mL of ammonia water is added dropwise, and the solution is stirred at 25 ℃ and 500rpm until the solution becomes a brown suspension. 2mL of an aqueous formaldehyde solution was added, and after about 7sec, the liquid turned turbid from clear. The temperature was maintained and stirring was carried out at 500rpm for 2 h. After the reaction is finished, centrifuging, washing by using 20% ethanol solution, drying, and observing by using an electron microscope to obtain the nitrogen content of the nitrogen-containing polymer nano microsphere of about 40%.

It will be apparent to those skilled in the art from this disclosure that many changes and modifications can be made, or equivalents modified, in the embodiments of the invention without departing from the scope of the invention. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention shall still fall within the protection scope of the technical solution of the present invention, unless the contents of the technical solution of the present invention are departed.

Claims

1. A method for preparing heteroatom-doped polymer nano-microspheres with cavity structures, which can be produced in large quantities, comprises the following steps:

with melamine;

the solvent is selected from one or a mixture of more of acetone, water, methanol, ethanol, dimethyl sulfoxide, N-N-dimethylformamide, tetrahydrofuran, glycol and N-propanol;

(2) adding an alkaline solution into the system, uniformly stirring, and adjusting the pH value of the system to 8-9; the alkaline solution is selected from one or more of ammonia water, sodium bicarbonate, sodium carbonate, sodium hydroxide, potassium carbonate or potassium bicarbonate solution;

(3) adding formaldehyde, glyoxal, malonaldehyde, succinaldehyde, glutaraldehyde or adipaldehyde into the system, and stirring for reaction to obtain a polymer nano microsphere solution;

(4) soaking or washing the obtained nano-microspheres in methanol, ethanol, formaldehyde or formic acid and a mixed solution thereof to obtain the nano-microspheres with a cavity structure;

one or more of o-aminobenzoic acid, p-aminobenzoic acid, m-aminobenzenesulfonic acid, o-aminobenzenesulfonic acid, p-aminobenzenesulfonic acid, 3, 5-diaminobenzoic acid or 2, 4-diaminobenzenesulfonic acid is/are formed into a solution in the step (1), wherein the concentration of the solution is 0.002-1.0 mol/L;

one or more of m-phenylenediamine, p-phenylenediamine, o-phenylenediamine, 2, 6-diaminopyridine, 1, 5-diaminonaphthalene, 1, 8-diaminonaphthalene or melamine is/are added into the solution in the step (1) to form a solution with the concentration of 0.002-1.0 mol/L;

the aldehyde is added in a dropwise manner, and the amount of the aldehyde group is 5-15 times equivalent relative to the arylamine.

2. The method of claim 1, wherein: and (3) adding the alkaline solution in the step (2) in a dropwise manner, wherein the stirring time is 1-6 hours.

3. The method of claim 1, wherein: and (3) adding aldehyde, and then stirring and reacting for 1-12 hours.

4. The heteroatom-doped polymer nanosphere with the cavity structure obtained by the preparation method according to any one of claims 1 to 3, wherein the nitrogen content of the nanosphere is 20-80 wt%, the diameter of the nanosphere is 100nm-1 μm, the particle size is uniform, the distribution of N heteroatoms is uniform, and when the prepared polymer nanosphere with the cavity structure contains S heteroatoms, the distribution of S heteroatoms is uniform.

5. The use of the heteroatom-doped polymer nanospheres with a cavity structure as defined in claim 4 as a positive electrode material of a lithium-sulfur battery.

6. The use of the heteroatom-doped polymer nanospheres with cavity structures as claimed in claim 4 as capacitor electrode material.