CN116062735A - Hard carbon prepared by non-sintering dehydration carbonization method and application thereof - Google Patents

Abstract

The invention belongs to the technical field of new energy storage materials, and particularly relates to hard carbon prepared by a non-sintering dehydration carbonization method and application thereof. The method comprises the steps of 1) dissolving a large amount of organic matters in a small amount of deionized water until the organic matters become supersaturated solution; 2) Dropping a reinforcing oxidant into the product obtained in the step 1) to obtain a hard carbon product; 3) And centrifugally cleaning the obtained product by using deionized water and drying to obtain the hard carbon material. The prepared material has excellent electrochemical performance, simple preparation process and low cost, and has wide application prospect.

Description

Preparation of hard carbon by a non-sintering dehydration carbonization method and its application

technical field

The invention belongs to the technical field of new energy storage materials, in particular to a non-sintering dehydration carbonization method for preparing hard carbon and its application.

Background technique

Carbon has abundant allotropes, such as diamond, graphite, amorphous carbon, carbon nanotubes, graphene, and carbyne, etc. Due to its excellent properties and wide range of applications, it has always been a research hotspot. Therefore, it is very important to explore new carbon allotropes with different carbon atom spatial arrangements, which will bring new properties, functions and applications. For example, graphite, the most commonly used anode material for commercial lithium-ion batteries (LIBs), has little electrochemical activity for sodium-ion batteries (SIBs), because the intercalation of Na ⁺ ions into the graphite interlayer space (0.335 nm) is thermodynamically unfavorable.

Hard carbons are generally considered as non-graphitizable carbons or disordered carbons, in which randomly oriented small-sized pseudographites with stacks of fingerprint layers are fixed by strong cross-linking of ^sp hybridized carbon atoms in the amorphous carbon domains, even At temperatures higher than 3000 °C, no real graphic structure can be formed. It has a large interlayer spacing greater than 0.37 nm between stacked graphene layers, which is beneficial for the intercalation/deintercalation of Na ⁺ ions, and the displayed favorable capacity is one of the most promising anode materials for SIBs.

Contents of the invention

In view of this, the object of the present invention is to provide a non-sintering dehydration carbonization method, by which a hard carbon material is obtained. In this method, the cost of raw materials is low, the preparation method is simple and feasible, and it can provide excellent performance as an electrode material, and has broad application prospects.

In order to realize above object of the invention, concrete technical scheme of the present invention is:

A non-sintering dehydration carbonization method, adopting the method to prepare a hard carbon material, the method comprises the following steps:

1) Dissolving a large amount of organic matter in a small amount of deionized water until it becomes a supersaturated solution;

2) drop a strong oxidizing agent into the product obtained in step (1) to obtain a hard carbon product;

3) The product obtained in step (2) is centrifugally washed with deionized water and dried to obtain a hard carbon material.

As a preferred embodiment of the present application, the organic matter described in step 1) is any one of sucrose, glucose, trehalose, ketohexose or starch.

As a preferred embodiment in this application, the ratio of organic matter to deionized water is 0.5g: 1mL to 4g: 1mL.

As a preferred embodiment of the present application, the strong oxidizing agent in step 2) is sulfuric acid.

As a preferred embodiment of the present application, the ratio between the strong oxidizing agent and the product obtained in step (1) is 0.1 mL: 1 g-1 mL: 1 g; more preferably 1 mL: 1 g.

As a preferred embodiment of the present application, the speed of the centrifugation described in step 3) is 3000-12000 rpm, the time is 3-10 minutes, and the drying temperature is 60-120°C.

Another object of the invention of the present application is to protect a hard carbon material obtained by adopting any of the above technical solutions or any combination of technical solutions.

The present invention also provides the application of the hard carbon material prepared by the above method, and the hard carbon material can be used as the negative electrode material of the sodium ion battery. For example, it is used to prepare hard carbon negative electrodes for sodium-ion batteries. In the activation process of 100mA/g, the first effect is 75.6%, and the specific capacity is 263mAh/g. At a current density of 1A/g, the specific capacity is 165mAh/g, indicating that the material has excellent electrochemical performance.

Compared with prior art, the beneficial effect of the present invention is:

(1) In this method, a high-concentration supersaturated solution is used, followed by strong oxidation and water to generate high temperature to carbonize the organic matter to obtain a hard carbon material. The hard carbon materials prepared by this method have abundant defects, which can enhance the electrochemical performance of the materials.

(2) The hard carbon material prepared by this method has good physical and chemical properties due to its rich closed-cell structure, more defects, unique pore structure and superior conductivity, so it can be better applied to lithium-ion batteries , Na-ion batteries, lithium/sodium-sulfur batteries, lithium/sodium-selenium batteries, water-based batteries, air batteries, sensors, environmental purification, energy, catalysis and other important fields.

Description of drawings:

Fig. 1 is the SEM picture of the hard carbon material 1# that embodiment 1 gains.

Fig. 2 is the TEM picture of hard carbon material 1# obtained in embodiment 1.

Fig. 3 is the XPS figure of the hard carbon material 1#, 2#, 3#, 4#, 5# of embodiment 1,2,3,4,5 gained.

Fig. 4 is the XRD pattern of hard carbon material 1#, 2#, 3#, 4#, 5# obtained in embodiment 1,2,3,4,5.

Fig. 5 is the Raman graph of hard carbon material 1# obtained in embodiment 1.

FIG. 6 is the first cycle charge and discharge curve of the hard carbon material 1# obtained in Example 1.

Fig. 7 is the cycle curve of hard carbon material 1# obtained in Example 1 at a current density of 1A g ^-1 .

Fig. 8 is the charge and discharge curves of the hard carbon material 1# obtained in Example 1 at a current density of 1 A/g with different numbers of cycles.

FIG. 9 is the CV curve of hard carbon material 1# obtained in Example 1 at a scan rate of 0.1 mV/s.

Detailed ways

In order to make the content of the present invention easier to understand, the process described in the present invention will be further described below in conjunction with the drawings and specific embodiments. However, it should not be construed that the scope of the above-mentioned subject matter of the present invention is limited to the following examples.

In the following examples, the described inert atmosphere is an argon atmosphere. The medicaments adopted in this application are all commercially available products.

Example 1:

A non-sintering dehydration carbonization method, as follows:

(1) Dissolve 20g of sucrose in 20mL of deionized water to form a high-concentration supersaturated solution;

(2) 20mL sulfuric acid (12M) is added dropwise in the product of gained, obtains hard carbon product;

(3) The obtained product was centrifuged at 12000 rpm for 5 minutes with deionized water, and repeated 4 times. Then the material was transferred to a blast drying oven at 70°C until it was dried to obtain hard carbon material 1#.

The hard carbon material was prepared using the same steps as in Example 1, except that the volume of sulfuric acid was replaced by 10 mL, 30 mL, 40 mL, 50 mL or 100 mL. The specific performance data are shown in Table 1:

Table 1:

The preparation of the hard carbon material was carried out in the same manner as in Example 1, the only difference being that sulfuric acid was replaced by hydrochloric acid or nitric acid. But failed to react.

Example 2:

A non-sintering dehydration carbonization method, as follows:

(1) Dissolve 20g of glucose in 20mL of deionized water to form a high-concentration supersaturated solution;

(2) 20mL sulfuric acid (12M) is added dropwise in the product of gained, obtains hard carbon product;

(3) The obtained product was centrifuged at 12000 rpm for 5 minutes with deionized water, and repeated 4 times. Then the material was transferred to a blast drying oven at 70°C until it was dried to obtain hard carbon material 2#.

The hard carbon material was prepared using the same steps as in Example 2, except that the volume of sulfuric acid was replaced by 10 mL, 30 mL, 40 mL, 50 mL or 100 mL. The specific performance data are shown in Table 2:

Table 2:

The preparation of the hard carbon material was carried out in the same method steps as in Example 2, the only difference being that the sulfuric acid was replaced by hydrochloric acid or nitric acid respectively. But failed to react.

Example 3:

A non-sintering dehydration carbonization method, as follows:

(1) Dissolve 20g trehalose in 20mL deionized water to form a high-concentration supersaturated solution;

(2) 20mL sulfuric acid (12M) is added dropwise in the product of gained, obtains hard carbon product;

(3) The obtained product was centrifuged at 12000 rpm for 5 minutes with deionized water, and repeated 4 times. Then the material was transferred to a blast drying oven at 70°C until it was dried to obtain hard carbon material 3#.

The hard carbon material was prepared using the same steps as in Example 3, except that the volume of sulfuric acid was replaced by 10 mL, 30 mL, 40 mL, 50 mL or 100 mL. The specific performance data are shown in Table 3:

table 3

The preparation of the hard carbon material was carried out in the same method steps as in Example 3, the only difference being that sulfuric acid was replaced by hydrochloric acid or nitric acid respectively. But failed to react.

Example 4:

A non-sintering dehydration carbonization method, as follows:

(1) Dissolve 20g of ketohexose in 20mL of deionized water to form a high-concentration supersaturated solution;

(2) Add 20 mL of sulfuric acid (12M) dropwise to the resulting product to obtain a hard carbon product;

(3) The obtained product was centrifuged at 12000 rpm for 5 minutes with deionized water, and repeated 4 times. Then the material was transferred to a blast drying oven at 70°C until it was dried to obtain hard carbon material 4#.

The hard carbon material was prepared using the same steps as in Example 4, except that the volume of sulfuric acid was replaced by 10 mL, 30 mL, 40 mL, 50 mL or 100 mL. The specific performance data are shown in Table 4:

Table 4:

The preparation of the hard carbon material was carried out in the same method steps as in Example 4, the only difference being that sulfuric acid was replaced by hydrochloric acid or nitric acid respectively. But failed to react.

Example 5:

A non-sintering dehydration carbonization method, as follows:

(1) Disperse 20g of starch in 20mL of deionized water to form a high-concentration supersaturated solution;

(2) Add 20 mL of sulfuric acid (12M) dropwise to the resulting product to obtain a hard carbon product;

(3) The obtained product was centrifuged at 12000 rpm for 5 minutes with deionized water, and repeated 4 times. Then the material was transferred to a blast drying oven at 70°C until it was dried to obtain hard carbon material 5#.

The hard carbon material was prepared using the same steps as in Example 5, except that the volume of sulfuric acid was replaced by 10 mL, 30 mL, 40 mL, 50 mL or 100 mL. The specific performance data are shown in Table 5:

table 5:

The preparation of the hard carbon material was carried out using the same method steps as in Example 5, the only difference being that sulfuric acid was replaced by hydrochloric acid or nitric acid. But failed to react.

Comparative example 1:

The method for preparing hard carbon material by solid phase method is prepared according to the following steps:

The sucrose was pyrolyzed in an inert atmosphere at 1300°C for 3 hours with a heating rate of 3°C per minute to obtain a hard carbon material.

The preparation of the hard carbon material was carried out using the same method steps as in Comparative Example 1, the only difference being that the pyrolysis temperature was replaced by 900, 1100, 1500 or 1700°C. Specific performance data are shown in Table 6

Table 6:

Comparative example 2:

The method for preparing hard carbon material by solid phase method is prepared according to the following steps:

Glucose was pyrolyzed at 1300° C. for 3 hours in an inert atmosphere with a heating rate of 3° C. per minute to obtain a hard carbon material.

The preparation of the hard carbon material was carried out using the same method steps as in Comparative Example 2, the only difference being that the pyrolysis temperature was replaced by 900, 1100, 1500 or 1700° C. respectively. The specific performance data are shown in Table 7:

Table 7:

Comparative example 3:

The method for preparing hard carbon material by solid phase method is prepared according to the following steps:

The trehalose was pyrolyzed in an inert atmosphere at 1300°C for 3 hours with a heating rate of 3°C per minute to obtain a hard carbon material.

The preparation of the hard carbon material was carried out using the same method steps as in Comparative Example 3, the only difference being that the pyrolysis temperature was replaced by 900, 1100, 1500 or 1700°C. The specific performance data are shown in Table 8:

Table 8:

Comparative example 4:

The method for preparing hard carbon material by solid phase method is prepared according to the following steps:

The ketohexose was pyrolyzed in an inert atmosphere at 1300°C for 3 hours with a heating rate of 3°C per minute to obtain a hard carbon material.

The preparation of the hard carbon material was carried out using the same method steps as in Comparative Example 4, the only difference being that the pyrolysis temperature was replaced by 900, 1100, 1500 or 1700°C. The specific performance data are shown in Table 9:

Table 9:

Comparative example 5:

The method for preparing hard carbon material by solid phase method is prepared according to the following steps:

The starch was pyrolyzed in an inert atmosphere at 1300°C for 3 hours, and the heating rate was 3°C per minute to obtain a hard carbon material.

The preparation of the hard carbon material was carried out using the same method steps as in Comparative Example 5, the only difference being that the pyrolysis temperature was replaced by 900, 1100, 1500 or 1700°C. The specific performance data are shown in Table 10:

Table 10:

experiment:

Hard carbon materials 1#, 2#, 3#, 4#, 5# prepared in Examples 1, 2, 3, 4, 5 and the materials prepared in Comparative Examples 1, 2, 3, 4, 5 were made respectively Sodium ion battery negative electrode and related performance tests.

Take hard carbon materials 1#, 2#, 3#, 4#, 5# and the materials prepared in comparative examples 1, 2, 3, 4, 5 and mix them with PVDF binder in a mass ratio of 90:10, then add An appropriate amount of NMP was ground into a paste in an agate mortar and spread on the aluminum current collector. A mass of approximately 2.5 mg of electrode active material is applied. Then, the electrode was vacuum-dried at 120° C. for 12 hours to obtain a negative electrode for a sodium ion battery. The metal sodium is used as the positive electrode, the electrolyte is NaPF ₆ in EC+DMC (vol%: 1:1), and the voltage range is 0.01-3V. The charge and discharge tester is Land CT2001A. The specific results are shown in Table 11.

Table 11 Hard carbon materials 1#, 2#, 3#, 4#, 5# and the electrochemical performance comparison table of materials in comparative examples 1, 2, 3, 4, 5:

Fig. 1 is the SEM image of the hard carbon material 1# obtained in Example 1 under different shooting magnifications, wherein a is 2000 times; b is 10000 times. From the low-magnification scanning electron microscope images, it can be seen that the material is bulky and the surface is rough, accompanied by the appearance of voids, which is the result of sulfuric acid etching.

Fig. 2 is the TEM image of the hard carbon material 1# obtained in Example 1 under different shooting magnifications, wherein the scale bar of a is 20nm; b is 1nm. It can be seen from the transmission electron microscope that there are abundant micropores and mesopores. At the same time, the lattice gap of disordered hard carbon can be observed.

Figure 3 is the XPS diagram of hard carbon materials 1#, 2#, 3#, 4#, and 5#. It was observed that only two elements, C and O, existed in the material.

Figure 4 is the XRD patterns of hard carbon materials 1#, 2#, 3#, 4#, 5#. It can be seen that the obtained material is a hard carbon material in the wide-packet diffraction peak at about 20 degrees, and the existence of other miscellaneous peaks is not detected.

Fig. 5 is the Raman graph of hard carbon material 1# obtained in embodiment 1. The D and G peaks belonging to carbon materials are clearly seen at 1350 and 1580.

FIG. 6 is the first cycle charge and discharge curve of the hard carbon material 1# obtained in Example 1. It can be seen from the figure that at a current density of 100mA/g, a plateau begins to appear at about 0.1V and a higher capacity is given.

Fig. 7 is the cycle curve of hard carbon material 1# obtained in Example 1 at a current density of 1A g ^-1 . It can be seen from the figure that the first effect of the material is 75.6% and the specific capacity is 263mAh/g during the activation process of 100mA/g. At a current density of 1A/g, the capacity is 165mAh/g, indicating that the material has good electrochemical performance.

Fig. 8 is the charge and discharge curves of the hard carbon material 1# obtained in Example 1 at a current density of 1 A/g with different numbers of cycles. It can be seen from the figure that the material has good cycle stability.

FIG. 9 is the CV curve of hard carbon material 1# obtained in Example 1 at a scan rate of 0.1 mV/s. It can be seen from the figure that the first circle and the second circle basically coincide, and the lateral verification material has excellent cycle stability.

Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that it can be described in terms of form and Various changes may be made in the details without departing from the scope of the invention defined by the claims.

Claims (10)

1. A non-sintering dehydration carbonization method, characterized by comprising the following steps:

1) Dissolving a large amount of organic matters in a small amount of deionized water until the solution becomes supersaturated solution;

2) Dropping a reinforcing oxidant into the product obtained in the step (1) to obtain a hard carbon product;

3) And (3) centrifugally cleaning and drying the product obtained in the step (2) by using deionized water to obtain the hard carbon material.

2. The non-sintering, dewatering and carbonizing method as set forth in claim 1, wherein: the organic matter in the step 1) is any one of sucrose, glucose, trehalose, hexulose or starch.

3. The non-sintering, dewatering and carbonizing method as set forth in claim 1, wherein: the strong oxidizing agent in step 2) is sulfuric acid.

4. The non-sintering, dewatering and carbonizing method as set forth in claim 1, wherein: the rotational speed of the centrifugation in the step 3) is 3000-12000 rmp, the time is 3-10 minutes, and the drying temperature is 60-120 ℃.

5. The non-sintering, dewatering and carbonizing method as set forth in claim 1, wherein: the ratio of organic matter to deionized water is 0.5g:1 mL-4 g:1mL.

6. The non-sintering, dewatering and carbonizing method as set forth in claim 1, wherein: the ratio of the strong oxidant to the product obtained in step (1) was 0.1mL:1g-1mL:1g.

7. The non-sintering, dewatering and carbonizing method as set forth in claim 2, wherein: the organic matter in the step 1) is sucrose, glucose or trehalose.

8. A hard carbon material prepared by the method of any one of claims 1-7.

9. The use of a hard carbon material according to claim 8, wherein: the hard carbon material is used as a negative electrode material of a sodium ion battery.

10. The use of a hard carbon material according to claim 9, wherein: the hard carbon material is used for preparing a hard carbon negative electrode of a sodium ion battery, and the initial effect of the hard carbon material in an activation process of 100mA/g is 75.6 percent, and the specific capacity is 165mAh/g under the current density of 1A/g.

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