阅读说明：本技术 氮/硫共掺杂多孔碳材料及其制备方法与用途 (Nitrogen/sulfur co-doped porous carbon material and preparation method and application thereof ) 是由 高勇军 熊彰熠 于 2020-11-30 设计创作，主要内容包括：本发明提供了一种氮/硫共掺杂多孔碳材料及其制备方法与用途,氮/硫共掺杂多孔碳材料中硫元素、氮元素分布于碳材料上；将1～6重量份的木质素磺酸钠、3重量份的氢氧化钾溶解于去离子水中得到木质素磺酸钠/氢氧化钾混合溶液,将木质素磺酸钠/氢氧化钾混合溶液喷涂在三聚氰胺海绵上,在惰性气氛下于500～900℃下高温煅烧1～3h,即可得到氮/硫共掺杂多孔碳材料。本发明制备方法简单,将生物质资源转化为高价值材料,成本低廉,所得氮/硫共掺杂多孔碳材料具有三维连通型多孔结构且孔结构可控,可作为超级电容器电极材料,具有能量密度大、循环稳定性好、较宽的温适等特点,电化学性能优良,应用前景广泛。(The invention provides a nitrogen/sulfur co-doped porous carbon material and a preparation method and application thereof, wherein sulfur and nitrogen in the nitrogen/sulfur co-doped porous carbon material are distributed on the carbon material; dissolving 1-6 parts by weight of sodium lignosulfonate and 3 parts by weight of potassium hydroxide in deionized water to obtain a sodium lignosulfonate/potassium hydroxide mixed solution, spraying the sodium lignosulfonate/potassium hydroxide mixed solution on melamine sponge, and calcining at a high temperature of 500-900 ℃ for 1-3 hours in an inert atmosphere to obtain the nitrogen/sulfur co-doped porous carbon material. The preparation method is simple, the biomass resource is converted into the high-value material, the cost is low, the obtained nitrogen/sulfur co-doped porous carbon material has a three-dimensional communicated porous structure, the pore structure is controllable, the nitrogen/sulfur co-doped porous carbon material can be used as a supercapacitor electrode material, the characteristics of high energy density, good circulation stability, wider temperature adaptability and the like are realized, the electrochemical performance is excellent, and the application prospect is wide.)

1. The nitrogen/sulfur co-doped porous carbon material is characterized in that the doping amounts of sulfur and nitrogen are 1.2-1.8 at% and 0.7-2.5 at% respectively, the sulfur and nitrogen are distributed on the carbon material, and the pore diameter of the carbon material is 0.5-3.5 nm.

2. The nitrogen/sulfur-codoped porous carbon material according to claim 1, wherein the nitrogen/sulfur-codoped porous carbon material is amorphous carbon and has a morphology comprising dendritic carbon and carbon nanosheets.

3. The nitrogen/sulfur-codoped porous carbon material according to claim 1, wherein the pore diameter of the nitrogen/sulfur-codoped porous carbon material is 2-2.5 nm.

4. The nitrogen/sulfur-codoped porous carbon material according to claim 1, wherein the specific surface area of the nitrogen/sulfur-codoped porous carbon material is 1323-2116 m²/g。

5. The nitrogen/sulfur-codoped porous carbon material according to claim 1, wherein the nitrogen/sulfur-codoped porous carbon material is prepared by the following method: dissolving 1-6 parts by weight of sodium lignosulfonate and 3 parts by weight of potassium hydroxide in deionized water to obtain a sodium lignosulfonate/potassium hydroxide mixed solution, coating the sodium lignosulfonate/potassium hydroxide mixed solution on 0.1-0.5 part by weight of melamine sponge, and calcining at a high temperature of 500-900 ℃ for 1-3 hours in an inert atmosphere to obtain the nitrogen/sulfur co-doped porous carbon material.

6. The method for preparing a nitrogen/sulfur co-doped porous carbon material according to claim 1, comprising the steps of:

(a) weighing 1-6 parts by weight of sodium lignosulfonate and 3 parts by weight of potassium hydroxide, and dissolving in deionized water to obtain a sodium lignosulfonate/potassium hydroxide mixed solution;

(b) coating the mixed solution of sodium lignosulfonate and potassium hydroxide on 0.1-0.5 part by weight of melamine sponge, and drying to obtain a prefabricated object;

(c) and calcining the prefabricated material at the high temperature of 500-900 ℃ for 1-3 h in the inert gas atmosphere, cooling, washing until the pH value is neutral, and drying to obtain the nitrogen/sulfur co-doped porous carbon material.

7. The method for preparing a nitrogen/sulfur co-doped porous carbon material according to claim 6, wherein in the step (b), the mixed solution of sodium lignosulfonate/potassium hydroxide is sprayed on the melamine sponge.

8. The method for preparing a nitrogen/sulfur co-doped porous carbon material according to claim 6, wherein in the step (c), the inert gas is nitrogen, and the flow rate is 30-50 mL/min.

9. Use of the nitrogen/sulfur-codoped porous carbon material as described in claim 1 in an electrode material.

10. A supercapacitor, characterized in that the nitrogen/sulfur-codoped porous carbon material according to claim 1 is used as an electrode material.

Technical Field

The invention relates to a doped carbon material, in particular to a nitrogen/sulfur co-doped porous carbon material and a preparation method and application thereof.

Background

With the increasing requirements of people on energy storage equipment, the traditional lithium ion battery can not meet the increasing requirements of people, so that the development of various green, environment-friendly, safe and efficient energy storage equipment becomes possible. The super capacitor is an advanced and green energy storage device, has the characteristics of quick charge and discharge, long cycle life, large power density and wider working temperature range, and has potential application prospects in the fields of electric automobiles, portable electronic products, power management systems and the like. However, the energy density of the super capacitor is only 5% of that of the lithium ion battery, which greatly restricts the application of the super capacitor. The electrode material of the super capacitor is the key for improving the capacitance, and the electrode materials commonly used at present mainly comprise conductive polymers, transition metal oxides, carbon materials and the like, so that the search for a low-cost green and environment-friendly preparation method is the premise of large-scale application of the super capacitor.

In the existing porous carbon material and the synthesis method thereof, the following technical problems to be improved and solved exist: the preparation process is generally complicated in steps, low in yield and the like; it is difficult to obtain a stably controlled pore structure; is difficult to produce in large scale. Therefore, it is of great significance to develop a new method for simply preparing a porous carbon material with a quantitatively controllable pore size.

The biomass carbon material is a natural and renewable resource, approximately 1049 million tons of biomass is generated all over the world every year, most of the biomass carbon material is simply burnt, waste is caused, a large amount of harmful gas generated by burning enters the atmosphere, serious environmental pollution and greenhouse effect are caused, and how to effectively utilize the biomass carbon material and convert the biomass carbon material into a material with high added value is one of the problems to be solved at present.

The information disclosed in this background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.

Disclosure of Invention

The invention aims to provide a nitrogen/sulfur co-doped porous carbon material, which aims to solve the technical problems that the existing biomass resource is difficult to efficiently utilize and the pore structure of the porous carbon material is difficult to quantitatively regulate and control.

The invention also aims to provide a preparation method of the nitrogen/sulfur co-doped porous carbon material, so as to solve the problems of complex process, low yield and difficulty in large-scale production of the existing porous carbon material preparation method.

The invention also aims to provide application of the nitrogen/sulfur co-doped porous carbon material.

The fourth purpose of the invention is to provide a supercapacitor adopting the nitrogen/sulfur co-doped porous carbon material as an electrode material.

One of the objects of the invention is achieved by:

the nitrogen/sulfur co-doped porous carbon material has the doping amounts of sulfur element and nitrogen element of 1.2-1.8 at% and 0.7-2.5 at% respectively, the sulfur element and the nitrogen element are distributed on the carbon material, and the pore diameter of the carbon material is 0.5-3.5 nm.

The nitrogen/sulfur co-doped porous carbon material is amorphous carbon and comprises dendritic carbon and carbon nanosheets.

Preferably, the doping amounts of the sulfur element and the nitrogen element are 1.2 to 1.72 at% and 0.7 to 2.42 at%, respectively.

Preferably, the aperture of the nitrogen/sulfur co-doped porous carbon material is 2-2.5 nm.

Preferably, the specific surface area of the nitrogen/sulfur co-doped porous carbon material is 1323-2116 m²/g。

The nitrogen/sulfur co-doped porous carbon material is prepared by adopting the following method: dissolving 1-6 parts by weight of sodium lignosulfonate and 3 parts by weight of potassium hydroxide in deionized water to obtain a sodium lignosulfonate/potassium hydroxide mixed solution, coating the sodium lignosulfonate/potassium hydroxide mixed solution on 0.1-0.5 part by weight of melamine sponge, and calcining at a high temperature of 500-900 ℃ for 1-3 hours in an inert atmosphere to obtain the nitrogen/sulfur co-doped porous carbon material.

When the carbon material is used as an electrode material, the CV curve presents a quasi-rectangle shape and has ideal characteristics of an electric double layer capacitor and pseudocapacitance; has good electrochemical performance, the coulombic efficiency of the electrochemical material reaches 93.65 percent, and when the current is 1Ag^-1Then the discharge time reaches 530s, and the specific capacitance reachesTo 481.82F g^-1。

The second purpose of the invention is realized by the following steps:

the preparation method of the nitrogen/sulfur co-doped porous carbon material comprises the following steps:

(a) weighing 1-6 parts by weight of sodium lignosulfonate and 3 parts by weight of potassium hydroxide, and dissolving in deionized water to obtain a sodium lignosulfonate/potassium hydroxide mixed solution;

(b) coating the mixed solution of sodium lignosulfonate and potassium hydroxide on 0.1-0.5 part by weight of melamine sponge, and drying to obtain a prefabricated object;

(c) and calcining the prefabricated material at the high temperature of 500-900 ℃ for 1-3 h in the inert gas atmosphere, cooling, washing until the pH value is neutral, and drying to obtain the nitrogen/sulfur co-doped porous carbon material.

In the step (a), preferably, 2-4 parts by weight of sodium lignosulfonate and 3 parts by weight of potassium hydroxide are dissolved in deionized water; more preferably, 3 parts by weight of sodium lignosulfonate and 3 parts by weight of potassium hydroxide are dissolved in deionized water; preferably, the sodium lignosulfonate/potassium hydroxide mixed solution is stirred uniformly by magnetic stirring.

In step (b), preferably, the melamine sponge is 0.3 parts by weight; preferably, the sodium lignosulfonate/potassium hydroxide mixed solution is uniformly sprayed on the melamine sponge by using a spray gun; preferably, the melamine sponge is cut into a specific shape including, but not limited to, a plate shape, a cylinder, a triangular prism, etc., and placed in a closed container to uniformly spray the sodium lignosulfonate/potassium hydroxide mixed solution on the melamine sponge; preferably, after spraying the mixed solution of sodium lignosulfonate/potassium hydroxide on the melamine sponge, the mixture is dried for at least 24 hours to obtain a prefabricated object.

In step (c), the inert gas can be selected from known inert gases of those skilled in the art, and the inert gas used in the present application is nitrogen; preferably, the flow rate of the inert gas is 30-50 mL/min, preferably 40 mL/min.

Preferably, heating is carried out at a heating rate of 5-150 ℃/min, preferably 10 ℃/min, and the temperature is increased to 500-900 ℃; preferably, the high-temperature calcination temperature is 700 ℃ and the high-temperature calcination time is 2 h.

Preferably, after naturally cooling to room temperature, washing by adopting an acid washing and water washing mode until the pH value is neutral; preferably, the acid is dilute sulfuric acid.

The third purpose of the invention is realized by the following steps:

the nitrogen/sulfur co-doped porous carbon material is applied to electrode materials, particularly super capacitor electrode materials and battery electrode materials.

When the nitrogen/sulfur co-doped porous carbon material is used as an electrode material, a counter electrode is a Pt electrode, and when the electrolyte is a 1M sulfuric acid solution, a CV curve presents a quasi-rectangle, so that the nitrogen/sulfur co-doped porous carbon material has ideal characteristics of an electric double layer capacitor and pseudo capacitance; has good electrochemical performance, the coulombic efficiency of the electrochemical material reaches 93.65 percent, and when the current is 1Ag^-1Then the discharge time reaches 530s, and the specific capacitance reaches 481.82F g^-1。

The fourth purpose of the invention is realized by the following steps:

a supercapacitor adopts the nitrogen/sulfur co-doped porous carbon material as an electrode material.

Preferably, the working electrode in the super capacitor is a nitrogen/sulfur co-doped porous carbon material, acetylene black and polytetrafluoroethylene which are mixed according to the mass ratio of 8.5:1:0.5 and coated on the surface of the super capacitor, wherein the area of the working electrode is 1 cm²The resulting electrode on a stainless steel mesh; the counter electrode was a Pt electrode and the electrolyte was a 1M sulfuric acid solution.

According to the invention, sodium lignosulfonate is used as a carbon source and a sulfur source, melamine sponge is used as a supporting framework and a nitrogen source, potassium hydroxide is used as an activating agent, the nitrogen/sulfur co-doped porous carbon material is prepared by a high-pressure spraying and one-step carbonization method, the obtained nitrogen/sulfur co-doped porous carbon material has a three-dimensional communicated porous structure, the pore structure is controllable, a reasonable and efficient ion transmission channel is constructed, the nitrogen/sulfur co-doped porous carbon material can be used as a supercapacitor electrode material, and the nitrogen/sulfur co-doped porous carbon material has the characteristics of large energy density, good circulation stability, wider.

The preparation method is simple, the biomass resources are fully utilized and converted into high-value materials, the cost is low, the method is suitable for industrial large-scale production, popularization and application, and the application prospect is wide.

Drawings

FIG. 1 is an XRD spectrum of the nitrogen/sulfur co-doped porous carbon material prepared in examples 1 to 4.

FIG. 2 is a TEM spectrum of the nitrogen/sulfur co-doped porous carbon material prepared in example 1, wherein a to d are TEM images at different scales respectively.

Fig. 3 is an energy spectrum of the nitrogen/sulfur co-doped porous carbon material prepared in example 1.

Fig. 4 is an X-ray electron energy spectrum of the nitrogen/sulfur co-doped porous carbon material prepared in example 1.

FIG. 5 is a Raman spectrum of the nitrogen/sulfur co-doped porous carbon material prepared in examples 1 to 4.

FIGS. 6 to 10 are respectively a nitrogen adsorption/desorption isotherm graph (FIG. a) and a pore size distribution graph (FIG. b) of the nitrogen/sulfur co-doped porous carbon material prepared in examples 1 to 5.

Fig. 11 is a CV curve of the nitrogen/sulfur co-doped porous carbon material prepared in example 1 as an electrode material.

Fig. 12 is a GCD curve using the nitrogen/sulfur co-doped porous carbon material prepared in example 1 as an electrode material.

Detailed Description

The invention is further illustrated by the following examples, which are given by way of illustration only and are not intended to limit the scope of the invention in any way.

Procedures and methods not described in detail in the following examples are conventional methods well known in the art, and the reagents used in the examples are either analytically or chemically pure and are either commercially available or prepared by methods well known to those of ordinary skill in the art. The following examples all achieve the objects of the present invention.

Example 1

Weighing 3g of sodium lignosulfonate and 3g of potassium hydroxide, dissolving in 20mL of deionized water, and uniformly stirring by magnetic force to obtain a sodium lignosulfonate/potassium hydroxide spraying solution; cutting 0.3g of melamine sponge into a cuboid shape, placing the cuboid shape in a closed container, uniformly spraying sodium lignosulfonate/potassium hydroxide spraying solution on the sponge by using a spray gun under the pressure of 5-7 bars, and placing the sponge in an oven for drying for more than 24 hours to obtain a prefabricated object; and transferring the prefabricated object into a tubular furnace, heating at the heating rate of 10 ℃/min under the protection of 40mL/min nitrogen, calcining at the high temperature of 700 ℃ for 2 hours, and cooling to obtain black foam, namely the nitrogen/sulfur co-doped porous carbon material.

XRD, TEM, X-ray electron energy spectrum, Raman spectrum and BET characterization are carried out on the obtained nitrogen/sulfur co-doped porous carbon material, and the obtained results are shown in figures 1-6.

From an XRD spectrogram, two peaks of the obtained nitrogen/sulfur co-doped porous carbon material sample respectively correspond to an 002 crystal face and a 101 crystal face of graphite. According to a TEM image, the obtained nitrogen/sulfur co-doped porous carbon material is amorphous carbon consisting of dendritic carbon and carbon nanosheets, and has a rich pore structure. As can be seen from the energy spectrum and the X-ray electron energy spectrum, the sulfur and nitrogen elements in the obtained nitrogen/sulfur co-doped porous carbon material are doped in the carbon material, and the sulfur and nitrogen elements are uniformly distributed on the carbon. As can be seen from the pore size distribution diagram, the obtained nitrogen/sulfur co-doped porous carbon material has narrow mesoporous size distribution (2-2.5 nm).

Example 2

Weighing 4 g of sodium lignosulfonate and 3g of potassium hydroxide, dissolving in 20mL of deionized water, and uniformly stirring by magnetic force to obtain a sodium lignosulfonate/potassium hydroxide spraying solution; cutting 0.3g of melamine sponge into a cuboid shape, placing the cuboid shape in a closed container, uniformly spraying sodium lignosulfonate/potassium hydroxide spraying solution on the sponge by using a spray gun under the pressure of 5-7 bars, and placing the sponge in an oven for drying for more than 24 hours to obtain a prefabricated object; and transferring the prefabricated object into a tubular furnace, heating at the heating rate of 10 ℃/min under the protection of 40mL/min nitrogen, calcining at the high temperature of 700 ℃ for 2 hours, cooling to room temperature, carrying out acid washing and water washing until the pH value is neutral, and drying to obtain black foam, namely the nitrogen/sulfur co-doped porous carbon material.

The obtained nitrogen/sulfur co-doped porous carbon material was characterized, and the obtained results are shown in fig. 1, 5 and 7.

Example 3

Weighing 1 g of sodium lignosulfonate and 3g of potassium hydroxide, dissolving in 20mL of deionized water, and uniformly stirring by magnetic force to obtain a sodium lignosulfonate/potassium hydroxide spraying solution; cutting 0.3g of melamine sponge into a cuboid shape, placing the cuboid shape in a closed container, uniformly spraying sodium lignosulfonate/potassium hydroxide spraying solution on the sponge by using a spray gun under the pressure of 5-7 bars, and placing the sponge in an oven for drying for more than 24 hours to obtain a prefabricated object; and transferring the prefabricated object into a tubular furnace, heating at the heating rate of 10 ℃/min under the protection of 40mL/min nitrogen, calcining at the high temperature of 700 ℃ for 2 hours, cooling to room temperature, carrying out acid washing and water washing until the pH value is neutral, and drying to obtain black foam, namely the nitrogen/sulfur co-doped porous carbon material.

The obtained nitrogen/sulfur co-doped porous carbon material was characterized, and the obtained results are shown in fig. 1, 5 and 8.

Example 4

Weighing 2 g of sodium lignosulfonate and 3g of potassium hydroxide, dissolving in 20mL of deionized water, and uniformly stirring by magnetic force to obtain a sodium lignosulfonate/potassium hydroxide spraying solution; cutting 0.3g of melamine sponge into a cuboid shape, placing the cuboid shape in a closed container, uniformly spraying sodium lignosulfonate/potassium hydroxide spraying solution on the sponge by using a spray gun under the pressure of 5-7 bars, and placing the sponge in an oven for drying for more than 24 hours to obtain a prefabricated object; and transferring the prefabricated object into a tubular furnace, heating at the heating rate of 10 ℃/min under the protection of 40mL/min nitrogen, calcining at the high temperature of 700 ℃ for 2 hours, cooling to room temperature, carrying out acid washing and water washing until the pH value is neutral, and drying to obtain black foam, namely the nitrogen/sulfur co-doped porous carbon material.

The obtained nitrogen/sulfur co-doped porous carbon material was characterized, and the obtained results are shown in fig. 1, 5 and 9.

Example 5

Weighing 3g of sodium lignosulfonate and 3g of potassium hydroxide, dissolving in 20mL of deionized water, and uniformly stirring by magnetic force to obtain a sodium lignosulfonate/potassium hydroxide spraying solution; cutting 0.3g of melamine sponge into a cuboid shape, placing the cuboid shape in a closed container, uniformly spraying sodium lignosulfonate/potassium hydroxide spraying solution on the sponge by using a spray gun under the pressure of 5-7 bars, and placing the sponge in an oven for drying for more than 24 hours to obtain a prefabricated object; and transferring the prefabricated object into a tubular furnace, heating at the heating rate of 10 ℃/min under the protection of 40mL/min nitrogen, calcining at the high temperature of 800 ℃ for 2 hours, and cooling to obtain black foam, namely the nitrogen/sulfur co-doped porous carbon material.

The obtained nitrogen/sulfur co-doped porous carbon material was characterized, and the obtained results are shown in fig. 1, 5 and 10.

BET test is performed on the nitrogen/sulfur co-doped porous carbon material prepared in examples 1 to 5, and the obtained results are shown in Table 1 below.

TABLE 1

Example 6

The nitrogen/sulfur co-doped porous carbon material prepared in example 1 was mixed with acetylene black and polytetrafluoroethylene at a mass ratio of 8.5:1:0.5, and applied to a surface area of 1 cm²The stainless steel wire mesh is dried in vacuum for more than 12 hours at 80 ℃, and is pressed into sheets, so that a working electrode is obtained, the electrolyte is 1M sulfuric acid solution, the reference electrode is an Ag/AgCl electrode, the counter electrode is a Pt electrode, a cyclic voltammetry test and a constant current charge-discharge test are carried out by using an electrochemical workstation, and the obtained results are shown in figures 11-12.

As can be seen from fig. 11, the CV curve shows a quasi-rectangle, and an oxidation peak appears at 0.39V and a reduction peak appears at 0.31V, which indicates that the nitrogen/sulfur co-doped porous carbon material has ideal electric double layer capacitor characteristics and pseudo capacitance; secondly, the GCD curve (FIG. 12) of the sample can also prove that the nitrogen/sulfur co-doped porous carbon material prepared in example 1 has good electrochemical performance, the coulombic efficiency reaches 93.65%, and when the current is 1Ag^-1Then the discharge time reaches 530s, and the specific capacitance reaches 481.82F g^-1。