阅读说明：本技术 一种超长循环多原子掺杂中空碳电极材料的制备及应用 (Preparation and application of ultra-long cycle polyatomic doping hollow carbon electrode material ) 是由 李宏岩 刘喜 孙影娟 于 2021-06-29 设计创作，主要内容包括：本发明属于钾离子电池领域,公开了一种超长循环多原子掺杂中空碳电极材料的制备方法及应用。本发明采用氧化镁微粒、六氯环三聚磷腈与二羟基二苯砜制备氧化镁-聚环三磷腈-二羟基二苯砜复合材料,经煅烧和除去氧化镁模板后,得到氮磷硫多原子共掺杂中空碳,即超长循环多原子掺杂中空碳电极材料。所述超长循环多原子掺杂中空碳电极材料的合成方法简单,比表面积大,具有交联结构以及丰富的缺陷和活性位点,作为钾离子电池负极材料可以较好地提高钾离子电池的倍率性能和循环稳定性。(The invention belongs to the field of potassium ion batteries, and discloses a preparation method and application of an ultralong-cycle polyatomic doping hollow carbon electrode material. The magnesium oxide-polycyclotriphosphazene-dihydroxy diphenylsulfone composite material is prepared by adopting magnesium oxide particles, hexachlorocyclotriphosphazene and dihydroxy diphenylsulfone, and after a magnesium oxide template is calcined and removed, nitrogen, phosphorus and sulfur multi-atom co-doped hollow carbon, namely the ultra-long cycle multi-atom doped hollow carbon electrode material, is obtained. The synthesis method of the ultra-long cycle polyatomic doping hollow carbon electrode material is simple, the specific surface area is large, the material has a cross-linking structure and abundant defects and active sites, and the material can be used as a potassium ion battery cathode material to better improve the rate capability and the cycle stability of a potassium ion battery.)

1. A preparation method of an ultra-long cycle polyatomic doping hollow carbon electrode material is characterized by comprising the following steps:

s1, dispersing nano magnesium oxide in methanol to form a dispersion solution 1, mixing hexachlorocyclotriphosphazene and 4,4' -dihydroxy diphenyl sulfone and dispersing in methanol to form a solution 2, and mixing the dispersion solution 1 and the solution 2 to obtain a dispersion solution 3; adding an acid-binding agent into the dispersion liquid 3 at room temperature, and reacting to obtain a magnesium oxide and polycyclotriphosphazene-4, 4' -dihydroxy diphenyl sulfone composite material;

s2, in an argon or nitrogen atmosphere, placing the magnesium oxide and polycyclotriphosphazene-4, 4' -dihydroxy diphenyl sulfone composite material prepared by the S1 in a tubular furnace for heating and calcining after centrifuging, washing and drying to obtain a calcined product of irregular cubic magnesium oxide and a carbon composite;

and S3, stirring the calcined product obtained in the step S2 in an acid solution to remove the template nano magnesium oxide, and obtaining nitrogen-phosphorus-sulfur doped hollow carbon, namely the ultra-long cycle polyatomic doped hollow carbon electrode material.

2. The preparation method of the ultra-long cycle polyatomic doping hollow carbon electrode material according to claim 1, wherein:

in the step S1, the particle size of the nano-magnesia is 20-100 nm, preferably 50 nm.

3. The preparation method of the ultra-long cycle polyatomic doping hollow carbon electrode material according to claim 1, wherein:

the acid-binding agent in the step S1 is triethylamine.

4. The preparation method of the ultra-long cycle polyatomic doping hollow carbon electrode material according to claim 1, wherein:

the dosage ratio of the nano magnesium oxide to the methanol in the dispersion liquid 1 in the step S1 is 0.01-10 g:10-50 ml;

in the solution 2 described in step S1, the molar ratio of hexachlorocyclotriphosphazene to 4,4' -dihydroxydiphenylsulfone is 1: the ratio of the total mass of the 1-3 hexachlorocyclotriphosphazene and the 4,4' -dihydroxy diphenyl sulfone to the amount of the methanol is 0.1-10g: 10 mL;

in the dispersion liquid 3 in the step S1, the mass ratio of the total mass of the hexachlorocyclotriphosphazene and the 4,4' -dihydroxy diphenyl sulfone to the nano magnesium oxide is 1-2: 2;

the dosage of the acid binding agent in the step S1 satisfies the following conditions: the dosage ratio of the hexachlorocyclotriphosphazene to the acid-binding agent is 0.1-10g:0.185 mL.

5. The preparation method of the ultra-long cycle polyatomic doping hollow carbon electrode material according to claim 1, wherein:

the reaction described in step S1 is a reaction at room temperature for 1-12 h.

6. The preparation method of the ultra-long cycle polyatomic doping hollow carbon electrode material according to claim 1, wherein:

the heating calcination in step S2 is to heat from room temperature to 700-1100 deg.C, preferably 900 deg.C, at a heating rate of 2-20 deg.C/min, and then keep the temperature for 1-24 h.

7. The preparation method of the ultra-long cycle polyatomic doping hollow carbon electrode material according to claim 1, wherein:

the acid solution in the step S3 is a hydrochloric acid solution, the concentration of the hydrochloric acid solution is 0.1-10 mol/L, and the dosage ratio of the calcined product to the hydrochloric acid solution is 0.0005-0.05 g:1 mL.

8. An ultra-long cycle polyatomic doping hollow carbon electrode material manufactured according to the method of any one of claims 1-7.

9. The material of claim 8, wherein the material is characterized by:

the BET specific surface area of the ultra-long cycle polyatomic doped hollow carbon electrode material is more than 700m²(g) mesopores are distributed on the surface.

10. The use of the ultra-long cycle polyatomic doping hollow carbon electrode material according to claim 8 or 9 as a negative electrode material for a potassium ion battery.

Technical Field

The invention belongs to the field of potassium ion batteries, and particularly relates to a preparation method and application of an ultra-long cycle polyatomic doping hollow carbon electrode material.

Background

The demand for new green and environmentally friendly energy is increasing with the rapid development of the economic society due to the non-renewable nature of fossil fuel energy and the pollution of the environment caused by the emission of chemical gases. The large-scale energy storage equipment is used as a carrier of novel energy, and the development significance is great. Lithium ion batteries are commercially used in energy devices, but the lack of lithium resources and the lack of excellent battery performance are bottlenecks that limit the development of potassium ion batteries. The potassium ion battery is taken as a powerful candidate, and rich potassium resources and standard oxidation-reduction potential similar to lithium can be embedded into a commercial graphite cathode material to realize theoretical capacity close to graphite, and the advantages of high voltage platform, energy density, conductivity and the like are widely concerned.

However, the larger potassium ion radiusMaking it difficult to achieve rapid intercalation and deintercalation in carbon materials, and the severe volume expansion changes caused by the intercalation/deintercalation process adversely affect the rate, capacity, and cycle performance of potassium ion batteries. Therefore, the reasonable design and development of the appropriate cathode material applied to the potassium ion battery are effective solutions, the rapid transmission and the effective storage of potassium ions are ensured, and the high electrochemical performance is realized. Various carbon materials with different structures and different modification modes are researched, wherein a heteroatom doping mode and a hollow carbon material become one of promising anode materials due to large specific surface area, abundant defects and active site structures, low cost and excellent chemical stability.

At present, there is a patent publication that uses a hollow carbon material as a negative electrode of a potassium ion battery. Chinese patent publication CN112079346A discloses a double-shell hollow spherical organic metal framework material and a preparation method thereof, a sulfonated polystyrene pellet is used as a template, and a novel nano spherical organic metal framework compound HS-ZIF-8 is synthesized by a hard template method, wherein the material has a double-shell hollow shell structure, but the particle size of the material is too large, so that the performance of a potassium ion battery is influenced. Chinese patent publication CN112499617A discloses a preparation method of a nitrogen-sulfur co-doped hollow carbon nanocube and a potassium ion battery, wherein a sodium chloride template is adopted to synthesize the nitrogen-phosphorus doped hollow carbon nanocube by taking citric acid monohydrate as a carbon source and nitrogen-sulfur compounds as a nitrogen source and a sulfur source. The material has a hollow cubic structure, but the specific surface area is small, so that the material is not beneficial to the adsorption of potassium ions.

Disclosure of Invention

In order to overcome the disadvantages and shortcomings of the prior art, the invention provides a preparation method of an ultra-long cycle polyatomic doping hollow carbon electrode material.

The invention also aims to provide the ultra-long cycle polyatomic doping hollow carbon electrode material prepared by the method.

The invention further aims to provide application of the ultra-long cycle polyatomic doping hollow carbon electrode material.

The purpose of the invention is realized by the following scheme:

a preparation method of an ultra-long cycle polyatomic doping hollow carbon electrode material comprises the following steps:

s1, dispersing nano magnesium oxide in methanol to form a dispersion solution 1, mixing hexachlorocyclotriphosphazene and 4,4' -dihydroxy diphenyl sulfone and dispersing in methanol to form a solution 2, and mixing the dispersion solution 1 and the solution 2 to obtain a dispersion solution 3; adding an acid-binding agent into the dispersion liquid 3 at room temperature, and reacting to obtain a magnesium oxide and polycyclotriphosphazene-4, 4' -dihydroxy diphenyl sulfone composite material;

s2, in an argon or nitrogen atmosphere, placing the magnesium oxide and polycyclotriphosphazene-4, 4' -dihydroxy diphenyl sulfone composite material prepared by the S1 in a tubular furnace for heating and calcining after centrifuging, washing and drying to obtain a calcined product of irregular cubic magnesium oxide and a carbon composite;

and S3, stirring the calcined product obtained in the step S2 in an acid solution to remove the template nano magnesium oxide, and obtaining nitrogen-phosphorus-sulfur-doped hollow carbon (NPS-HC for short), namely the ultra-long cycle polyatomic doping hollow carbon electrode material.

The particle size of the nano magnesium oxide in the step S1 is 20-100 nm, preferably 50 nm;

the dosage ratio of the nano magnesium oxide to the methanol in the dispersion liquid 1 in the step S1 is 0.01-10 g:10-50 ml;

the mole ratio of hexachlorocyclotriphosphazene to 4,4' -dihydroxydiphenylsulfone described in step S1 is 1: 1-3, wherein the mass ratio of the total mass of the hexachlorocyclotriphosphazene and the 4,4 '-dihydroxy diphenyl sulfone to the amount of methanol in the solution 2 is 0.1-10g: 10mL, and the mass ratio of the total mass of the hexachlorocyclotriphosphazene and the 4,4' -dihydroxy diphenyl sulfone to the nano magnesium oxide is 1-2: 2;

the acid-binding agent in the step S1 is triethylamine, and the dosage of the acid-binding agent satisfies the following conditions: the dosage ratio of the hexachlorocyclotriphosphazene to the acid-binding agent is 0.1-10g:0.185 mL;

the reaction described in step S1 is a reaction at room temperature for 1-12 h.

The heating and calcining in the step S2 means heating to 700-1100 ℃ at a heating rate of 2-20 ℃/min, preferably 900 ℃, and then preserving the heat for 1-24 h.

The acidic solution in the step S3 is a hydrochloric acid solution, the concentration of the hydrochloric acid solution is 0.1-10 mol/L, the dosage ratio of the calcined product to the hydrochloric acid solution is 0.0005-0.05 g:1mL, and the stirring in the step S3 is 1-72 h.

The super-long cycle polyatomic doped hollow carbon electrode material prepared by the method has the BET specific surface area of more than 700m²G, and a plurality of mesopores are distributed on the surface.

The application of the ultra-long cycle polyatomic doping hollow carbon electrode material in the aspect of potassium ion battery negative electrode materials.

Compared with the prior art, the invention has the following advantages and beneficial effects:

the invention provides a preparation method and application of an ultra-long cycle polyatomic doping hollow carbon electrode material.

Drawings

Fig. 1 is a scanning electron microscope photograph of the ultra-long cycle polyatomic doping hollow carbon electrode material prepared in example 1.

Fig. 2 is a transmission electron microscope photograph of the ultra-long cycle polyatomic doping hollow carbon electrode material prepared in example 1.

Fig. 3 is an X-ray photoelectron spectrum of the ultra-long cycle polyatomic doping hollow carbon electrode material prepared in example 1.

Fig. 4 is a nitrogen adsorption/desorption curve of the ultra-long cycle polyatomic-doped hollow carbon electrode material prepared in example 1.

FIG. 5 shows the ultra-long cycle polyatomic doping of hollow carbon electrode materials prepared in example 1 at 2000mA g^-1Current density of (a).

FIG. 6 shows the ultra-long cycle polyatomic doping of hollow carbon electrode materials prepared in example 1 at 1000mA g^-1Current density of (a).

Fig. 7 is a graph of rate capability of the ultra-long cycle polyatomic doping hollow carbon electrode material prepared in example 1 at different current densities.

Detailed Description

The present invention will be described in further detail with reference to examples and drawings, but the embodiments of the present invention are not limited thereto. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.

The reagents used in the examples are commercially available without specific reference.

Example 1

The method comprises the following steps: 400mg of nano-magnesia having a particle size of 50nm were dispersed in 50ml of methanol.

Step two: the hexachlorocyclotriphosphazene and 4,4' -dihydroxydiphenylsulfone, having a total mass of 228mg and a molar ratio of 1:2.25, were dissolved in 10ml of methanol.

Step three: adding the solution in the step two into the solution in the step one, adding 185 mu L of triethylamine in the stirring process, and keeping normal temperature for polymerization for 6 h.

Step four: and (3) centrifuging, washing and drying the product obtained in the third step, then placing the product in a tubular furnace for heat treatment, heating the product to 900 ℃ from room temperature in a nitrogen atmosphere at the heating rate of 2 ℃/min, preserving the heat for 2h for full calcination, and obtaining a calcined product after the calcination is finished.

Step five: and removing the magnesium oxide template from the calcined product obtained in the fourth step by using 3mol/L hydrochloric acid to obtain the nitrogen-phosphorus-sulfur doped hollow carbon, namely the ultra-long cycle polyatomic doped hollow carbon electrode material.

Example 2

The method comprises the following steps: 400mg of nano-magnesia having a particle size of 100nm were dispersed in 50ml of methanol.

Steps two through five are identical to example 1.

Example 3

Steps one to three are identical to example 1.

Step four: and (3) centrifuging, washing and drying the product obtained in the third step, then placing the product in a tube furnace for heat treatment, heating the product to 700 ℃ from room temperature in a nitrogen atmosphere at a heating rate of 2 ℃/min, keeping the temperature for 2h for full calcination, and obtaining a calcined product after the calcination is finished.

Step five was identical to example 1.

Example 4

Steps one to three are identical to example 1.

Step four: and (3) centrifuging, washing and drying the product obtained in the third step, then placing the product in a tube furnace for heat treatment, heating the product to 1100 ℃ from room temperature in a nitrogen atmosphere at the heating rate of 2 ℃/min, preserving the heat for 2h for full calcination, and obtaining a calcined product after the calcination is finished.

Step five was identical to example 1.

The shape analysis and performance test of the ultra-long cycle polyatomic doping hollow carbon electrode material obtained in the embodiment have the following results:

fig. 1 is a scanning electron micrograph of the ultra-long cycle polyatomic doping hollow carbon electrode material prepared in example 1, which is seen from fig. 1 to have an irregular cubic shape.

Fig. 2 is a transmission electron micrograph of the ultra-long cyclic polyatomic doping hollow carbon electrode material prepared in example 1, and it can be seen from fig. 2 that the hollow carbon structures are cross-linked with each other.

Fig. 3 is an X-ray photoelectron spectrum of the ultra-long cycle polyatomic doping hollow carbon electrode material prepared in example 1, and it can be known from fig. 3 that three atoms of nitrogen, phosphorus and sulfur are successfully doped.

Fig. 4 is a nitrogen adsorption/desorption graph of the ultra-long cycle polyatomic doped hollow carbon electrode material prepared in example 1, and as can be seen from fig. 4, it is a typical iv-type adsorption/desorption curve, indicating that the material is a mesoporous structure.

FIG. 5 shows the ultra-long cycle polyatomic doping of hollow carbon electrode materials prepared in example 1 at 2000mA g^-1As can be seen from fig. 5, the material has excellent cycling stability as a negative electrode material of a potassium ion battery.

FIG. 6 shows the ultra-long cycle polyatomic doping of hollow carbon electrode materials prepared in example 1 at 1000mA g^-1As can be seen from fig. 6, the material has excellent cycling stability and ultra-long cycle life as a negative electrode material of a potassium ion battery.

Fig. 7 is a graph of rate performance of the ultra-long cycle polyatomic doping hollow carbon electrode material prepared in example 1 at different current densities, and it can be seen from fig. 7 that the material has excellent rate performance as a negative electrode material of a potassium ion battery.

The ultra-long cycle polyatomic doping hollow carbon electrode material prepared in the examples 1 to 4 is used as the negative electrode material of the potassium ion battery and is measured at 2000mA g^-1The initial specific capacity at current density and capacity retention after 1000 cycles are shown in table 1.

TABLE 1 initial specific capacity and capacity retention of examples 1-4

	Initial specific capacity	Capacity retention rate
			Example 1	257.4mAh/g	73.97％
Example 2	210.5mAh/g	70.68％
			Example 3	180.7mAh/g	62.95％
Example 4	167.8mAh/g	60.51％

The test results in table 1 show that the ultra-long cycle polyatomic doping hollow carbon electrode material prepared in each example is used as a negative electrode material of a potassium ion battery, and the potassium ion battery can obtain higher initial specific capacity and good capacity retention rate. As is clear from comparison of data in examples 1 to 4 in Table 1, the particle size of the magnesium oxide particles is preferably 20 to 100nm, more preferably 50nm, and the calcination temperature is preferably 700 to 1100 ℃, more preferably 900 ℃.

The above embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents thereof, and all such changes, modifications, substitutions, combinations, and simplifications are intended to be included in the scope of the present invention.