阅读说明：本技术 一种非晶碳化硼及其制备方法和应用 (Amorphous boron carbide and preparation method and application thereof ) 是由 陈元振 杨雷 吕光军 戴欣 于 2021-09-29 设计创作，主要内容包括：本发明公开了一种非晶碳化硼及其制备方法和应用,所述制备方法包括以下步骤：将预选取的碳源与硼源混合均匀,获得混合均匀的粉体；将所述混合均匀的粉体在保护气氛下升温至800～1500℃,保温1～5h后冷却至室温,制备获得非晶碳化硼。综上,本发明为解决现有的人造石墨生产过程中因反应温度过高而引起的生产成本过高,且石墨化程度低,从而影响锂离子电池负极容量及首次库伦效率低的问题,提供了一种非晶态的催化剂的制备方法；采用非晶态的催化剂可提高石墨化程度、降低石墨化温度,从而提高石墨负极的容量及首次库伦效率。(The invention discloses amorphous boron carbide and a preparation method and application thereof, wherein the preparation method comprises the following steps: uniformly mixing a pre-selected carbon source with a boron source to obtain uniformly mixed powder; and heating the uniformly mixed powder to 800-1500 ℃ under a protective atmosphere, preserving heat for 1-5h, and cooling to room temperature to obtain the amorphous boron carbide. In conclusion, the invention provides a preparation method of an amorphous catalyst, aiming at solving the problems that the production cost is too high and the graphitization degree is low due to too high reaction temperature in the existing production process of artificial graphite, so that the negative electrode capacity and the first coulombic efficiency of a lithium ion battery are influenced; the non-crystalline catalyst can improve the graphitization degree and reduce the graphitization temperature, thereby improving the capacity and the first coulomb efficiency of the graphite cathode.)

1. The preparation method of amorphous boron carbide is characterized by comprising the following steps:

uniformly mixing a pre-selected carbon source with a boron source to obtain uniformly mixed powder;

and heating the uniformly mixed powder to 800-1500 ℃ under a protective atmosphere, preserving heat for 1-5h, and cooling to room temperature to obtain the amorphous boron carbide.

2. The method for preparing amorphous boron carbide according to claim 1, wherein the boron source is one or both of diboron trioxide and boric acid; the carbon source is selected from one or more of anthracite, semicoke, petroleum coke, coal tar coke, calcined coke and asphalt.

3. The method of claim 2, wherein the mass ratio of the carbon reducing agent to the boron oxide is 0.6 during the process of uniformly mixing the pre-selected carbon source and the boron source.

4. The method for preparing amorphous boron carbide according to claim 1, wherein the step of uniformly mixing the pre-selected carbon source with the boron source to obtain the uniformly mixed powder specifically comprises:

and performing ball milling treatment on the pre-selected carbon source and the boron source, and then uniformly mixing to obtain uniformly mixed powder.

5. The method for preparing amorphous boron carbide according to claim 1, wherein the temperature rise rate is 10 ℃/min in the process of raising the temperature of the uniformly mixed powder to 800-1500 ℃ in a protective atmosphere.

6. The method for preparing amorphous boron carbide according to claim 1, wherein the uniformly mixed powder is heated to 800-1500 ℃ in a protective atmosphere, wherein the protective atmosphere is argon or nitrogen.

7. An amorphous boron carbide produced by the production method described in any one of claims 1 to 6.

8. Use of amorphous boron carbide according to claim 7 for catalysing graphitization of carbon based materials.

9. The use of amorphous boron carbide according to claim 8, wherein the step of catalyzing graphitization of the carbon-based material specifically comprises:

ball-milling amorphous boron carbide and a carbon-based material, and uniformly mixing to obtain mixed powder;

and heating the mixed powder to 2500-2800 ℃ under a protective atmosphere, preserving the heat for 1-10 h, and cooling to room temperature to obtain the artificial graphite material.

10. The application of the amorphous boron carbide of claim 9, wherein the mixed powder has a particle size of 1-3 μm; the particle size of the carbon-based material is 5-15 μm.

Technical Field

The invention belongs to the technical field of lithium ion batteries, relates to the technical field of graphitization of carbon-based materials, and particularly relates to amorphous boron carbide and a preparation method and application thereof.

Background

Lithium ion batteries are representative of new generation energy storage devices due to their advantages of high energy density, ultra-small self-discharge effect, greenness, no pollution, etc. Heretofore, artificial graphite is still the mainstream negative electrode material of lithium ion batteries, and is irreplaceable in commercial lithium ion batteries due to the characteristics of low potential, low volume expansion, stable cycle life, higher capacity and the like.

However, the synthesis temperature of the needle coke and the like used for preparing the artificial graphite is up to 3000 ℃, which not only has high requirements on equipment, but also brings great power and equipment loss, and is undoubtedly not favorable for controlling the cost; as another example, in other production technologies using low-cost carbon-based materials (such as coal, petroleum coke, and coal-oil coke) as raw materials, even though the performance of the graphite material obtained at this temperature is greatly improved, the conversion rate of graphite is low, the temperature required for reaction is too high, and the specific capacity is still greatly different from the theoretical capacity, which still fails to achieve the expected target.

In view of the problems of high-temperature graphitization, researchers find that catalytic graphitization is expected to solve the problem of adding a metal and a compound thereof, a non-metal compound and the like with special properties to a formulation to promote graphitization of a carbon-based material at a lower temperature or to achieve a higher graphitization degree at the same temperature. The currently selected catalysts mainly comprise elements such as nickel, cobalt, iron, manganese, calcium, silicon and the like and compounds thereof, but the effects of the catalysts are not obvious no matter in the aspects of improving the graphitization degree or controlling the graphitization temperature. In addition, boron has good effect on catalyzing the graphitization of the carbon material, but the cost is high, so that the boron is not suitable for commercial mass production of artificial graphite.

In summary, it is desirable to invent a catalyst that is low in cost and can effectively catalyze graphitization, increase the graphitization degree of the carbon-based material or reduce the graphitization temperature.

Disclosure of Invention

The invention aims to provide amorphous boron carbide and a preparation method and application thereof, so as to solve one or more technical problems. Specifically, the invention provides a preparation method of an amorphous catalyst, aiming at solving the problems that the production cost is too high and the graphitization degree is low due to too high reaction temperature in the existing production process of artificial graphite, so that the negative electrode capacity of a lithium ion battery is influenced and the first coulombic efficiency is low; the non-crystalline catalyst can improve the graphitization degree and reduce the graphitization temperature, thereby improving the capacity and the first coulomb efficiency of the graphite cathode.

In order to achieve the purpose, the invention adopts the following technical scheme:

the invention relates to a preparation method of amorphous boron carbide, which comprises the following steps:

uniformly mixing a pre-selected carbon source with a boron source to obtain uniformly mixed powder;

and heating the uniformly mixed powder to 800-1500 ℃ under a protective atmosphere, preserving heat for 1-5h, and cooling to room temperature to obtain the amorphous boron carbide.

The further improvement of the invention is that the boron source selects one or two of diboron trioxide and boric acid; the carbon source is selected from one or more of anthracite, semicoke, petroleum coke, coal tar coke, calcined coke and asphalt.

The invention has the further improvement that in the process of uniformly mixing the preselected carbon source and the boron source, the mass ratio of the carbon reducing agent to the boron oxide is 0.6.

The further improvement of the invention is that the step of uniformly mixing the pre-selected carbon source and the boron source to obtain uniformly mixed powder specifically comprises the following steps: and performing ball milling treatment on the pre-selected carbon source and the boron source, and then uniformly mixing to obtain uniformly mixed powder.

The further improvement of the invention is that in the process of heating the uniformly mixed powder to 800-1500 ℃ under the protective atmosphere, the heating rate is 10 ℃/min, and the protective atmosphere is argon or nitrogen.

The amorphous boron carbide prepared by the preparation method provided by the invention.

The application of the amorphous boron carbide prepared by the preparation method is used for catalyzing the graphitization of the carbon-based material.

A further improvement of the present invention is that the step of catalyzing graphitization of the carbon-based material specifically comprises:

ball-milling amorphous boron carbide and a carbon-based material, and uniformly mixing to obtain mixed powder;

and heating the mixed powder to 2500-2800 ℃ under a protective atmosphere, preserving the heat for 1-10 h, and cooling to room temperature to obtain the artificial graphite material.

The invention has the further improvement that the grain diameter of amorphous boron carbide in the mixed powder is between 1 and 3 mu m; the particle size of the carbon-based material is 5-15 μm.

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

amorphous boron carbide (B) prepared by the invention₄C_x) Is synthesized at low temperature, and has low crystallization degree; furthermore, when the carbon-based material is used as a catalyst, the graphitization degree of the carbon-based material can be obviously improved by adding substances with different contents, so that the specific capacity of the electrode material is improved; but also can reduce the graphitization temperature to a certain extent.

The boron source for preparing the amorphous boron carbide in the invention is B₂O₃Or H₃BO₃The carbon source is anthracite, semicoke, petroleum coke, coal tar coke, calcined coke, asphalt and the like, the cost of the raw materials is very low, the preparation equipment is simple, the operation is convenient, and the industrial production in large batch is easy.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art are briefly introduced below; it is obvious that the drawings in the following description are some embodiments of the invention, and that for a person skilled in the art, other drawings can be derived from them without inventive effort.

FIG. 1 is a comparison graph of the charge and discharge cycle performance of the electrode material at 0.5C after graphitization and heat preservation at 2800 ℃ for 1 hour after adding 0%, 10%, 15%, 20% 800 ℃ amorphous boron carbide into the semi-coke in the example of the invention;

FIG. 2 is a schematic diagram of the first charging and discharging curves of the electrode material at 0.1C after adding 0%, 10%, 15% and 20% 800 ℃ amorphous boron carbide to the semi-coke and graphitizing and preserving heat at 2800 ℃ for 1 hour in the example of the present invention;

FIG. 3 is a graph showing the rate performance curves of the electrode material charged and discharged at different currents after graphitization and heat preservation at 2800 ℃ for 1 hour after 0%, 10%, 15%, 20% 800 ℃ amorphous boron carbide is added to the semicoke in the example of the present invention;

FIG. 4 is a comparison graph of cycle performance of graphite electrodes obtained by graphitizing and maintaining semicoke added with 0% and 15% of 800 ℃ amorphous boron carbide at 2800 ℃ and 2500 ℃ for 1 hour at 0.5C rate during charging and discharging in the example of the present invention;

FIG. 5 is a schematic diagram showing the first charging and discharging curves of graphite electrodes prepared by graphitizing and maintaining the temperature of semicoke added with 0% and 15% of 800 ℃ amorphous boron carbide at 2800 ℃ and 2500 ℃ for 1 hour at 0.1C in the example of the present invention;

FIG. 6 is a graph showing the comparison of the rate capability of graphite electrodes obtained by graphitizing and maintaining the semicoke added with 0% and 15% of 800 ℃ amorphous boron carbide at 2800 ℃ and 2500 ℃ for 1 hour at different currents during charging and discharging in the example of the present invention.

Detailed Description

In order to make the technical solutions of the present invention better understood, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that the terms "first," "second," and the like in the description and claims of the present invention and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the invention described herein are capable of operation in sequences other than those illustrated or described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

The invention is described in further detail below with reference to the accompanying drawings:

the preparation method of the amorphous boron carbide provided by the embodiment of the invention comprises the following steps:

uniformly mixing a carbon source and a boron source in a preset proportion to obtain uniformly mixed powder;

and heating the uniformly mixed powder to 800-1500 ℃ at a speed of 10 ℃/min under a protective atmosphere, preserving heat for 1-5h, and cooling to room temperature to prepare the amorphous boron carbide.

Illustratively, the predetermined ratio is 0.6 (mass ratio of the carbonaceous reducing agent to the boron oxide).

Specifically, the step of uniformly mixing the carbon source and the boron source in a preset proportion specifically comprises the following steps: and performing ball milling treatment on the carbon source and the boron source in a preset proportion and uniformly mixing.

Specifically, the boron source is selected from low-cost diboron trioxide (B)₂O₃) Or boric acid (H)₃BO₃) The carbon source used as the reducing agent can be anthracite, semicoke, petroleum coke, kerosene coke, calcined coke or asphalt.

Specifically, the protective atmosphere is argon or nitrogen.

To sum up, the embodiment of the invention aims to solve the problems that the production cost is too high and the graphitization degree is low due to too high reaction temperature in the existing production process of artificial graphite, so that the negative electrode capacity and the first coulombic efficiency of a lithium ion battery are affected, and particularly provides a method for improving the graphitization degree and reducing the graphitization temperature by using an amorphous catalyst, so that the capacity and the first coulombic efficiency of a graphite negative electrode are improved.

Amorphous boron carbide (B) of an embodiment of the invention₄C_x) The preparation process is completed according to the following steps:

selecting boron source from boron trioxide (B) with low cost₂O₃) Or boric acid (H)₃BO₃) The carbon source used as the reducing agent can be anthracite, semicoke, petroleum coke, kerosene coke, calcined coke, asphalt and the like.

Respectively weighing a carbon source and a boron source according to the mass ratio of the carbon reducing agent to the boron oxide of 0.6, wherein the boron source is easy to evaporate in the reaction process, so that the boron source is excessive in proportion to the theoretical proportion, and then pouring the weighed sample into a ball milling tank for uniformly mixing.

And transferring the uniformly mixed powder into a corundum porcelain boat, then putting the corundum porcelain boat into a tube furnace for heating, wherein the protective atmosphere is argon, heating to a preset temperature, and then preserving heat for 1-5 hours.

And finally, slowly cooling the sample to room temperature along with the furnace to obtain black blocky amorphous boron carbide.

Amorphous boron carbide (B) of an embodiment of the invention₄C_x) The catalytic graphitization process of the carbon-based material comprises the following steps:

firstly, putting amorphous boron carbide into a planetary ball mill for ball milling for 2-4 h, controlling the particle size of the amorphous boron carbide to be 1-3 mu m, and enabling the amorphous boron carbide to be fully contacted with a carbon-based material when being mixed so as to achieve the best catalytic effect. Then respectively weighing 10%, 15% and 20% of amorphous boron carbide and the carbon-based material, and uniformly mixing in a planetary ball mill, wherein the particle size of the carbon-based material is controlled to be 5-15 mu m.

And then putting the uniformly mixed powder into a graphite crucible. And then putting the graphite into a high-temperature graphitization furnace for heat treatment, setting the temperature to be 2500-2800 ℃, preserving the heat for 1-10 hours, and naturally cooling to room temperature after the heat preservation is finished to obtain the artificial graphite material.

Amorphous boron carbide (B) prepared by the invention₄C_x) Is synthesized at low temperature, and has low crystallization degree; when the carbon-based carbon material is used as a catalyst, the graphitization degree of the carbon-based material can be obviously improved by adding the substances with different contents, so that the specific capacity of the electrode material is improved; but also can reduce graphite to a certain extentThe temperature of the solution is changed.

The boron source for preparing the amorphous boron carbide in the invention is B₂O₃Or H₃BO₃The carbon source is anthracite, semicoke, petroleum coke, coal tar coke, calcined coke, asphalt and the like, the cost of the raw materials is very low, the preparation equipment is simple, the operation is convenient, and the industrial production in large batch is easy.

The invention provides amorphous boron carbide (B)₄C_x) The preparation method and the application thereof in catalyzing the graphitization of the carbon-based material specifically comprise the following steps: reducing boron oxide at low temperature by using a carbothermic method to obtain black blocky amorphous boron carbide; adding the obtained amorphous boron carbide into a carbon-based material, and carrying out catalytic graphitization at high temperature to obtain the artificial graphite material with improved performance. The amorphous boron carbide provided by the invention not only can obviously improve the specific capacity of the carbon-based material, but also can reduce the graphitization temperature to a certain extent and improve the first coulombic efficiency of the carbon-based material, and the method is low in cost, simple and convenient to operate and suitable for large-scale production.

Detailed description of the preferred embodiment 1

The method for preparing amorphous boron carbide by using the carbothermic method comprises the following steps:

mixing materials: according to the carbo-reductants with B₂O₃The mixing ratio (weight ratio) of the components is 0.6, the weighed powder is poured into a mixing tank, the ball-material ratio is 10:1, the rotating speed is 450r/min, and the powder is mixed in a planetary ball mill for 3 hours until the powder is completely uniform.

C, carbothermic reduction: and transferring the uniformly mixed powder into a corundum porcelain boat of 3 multiplied by 8cm, and then putting the porcelain boat into a tube furnace for heating. Before heating, argon is introduced for 20-30 min to remove air in the quartz tube, then argon flow is controlled to be minimum to form argon protective atmosphere, a heating program is set to raise the temperature to 800-1500 ℃ at a speed of 10 ℃/min, then heat preservation is carried out for 1-5h, and finally the sample is slowly cooled to room temperature along with the furnace, and finally a black blocky product is obtained.

Specific example 2

The amorphous boron carbide catalytic graphitization method provided by the embodiment of the invention comprises the following steps:

grinding and mixing the catalyst: firstly, crushing massive amorphous boron carbide, and then putting the crushed amorphous boron carbide into a planetary ball mill for ball milling for 3 hours; then weighing a certain amount of carbon source powder, and uniformly mixing in a planetary ball mill for 30 min. The ball material ratio is 10:1, the rotating speed is 450 r/min. And mixing the ground catalyst and carbon source powder according to a certain proportion, and mixing and stirring for 1 hour by using a mixer to obtain composite powder.

And (3) catalytic graphitization: weighing 2g of the uniformly mixed amorphous boron carbide and carbon source powder, and transferring the amorphous boron carbide and the carbon source powder into a graphite crucible; and then putting the graphite into a high-temperature graphitization furnace for heat treatment, wherein the protective atmosphere is argon, the temperature is raised to the graphitization temperature of 2500-2800 ℃, then the heat is preserved for 1-10 hours, and after the graphitization process is finished, the graphite is naturally cooled to the room temperature, so that the artificial graphite material can be obtained.

The invention prepares amorphous boron carbide by a simple carbothermic method, and uses the amorphous boron carbide as a catalyst for catalytic graphitization, thereby realizing a preparation method for preparing artificial graphite which can improve the capacity of carbon-based materials and reduce graphitization temperature. The preparation process does not comprise any high-cost raw materials, is simple and convenient to operate, greatly reduces the production cost, and lays a foundation for industrial mass production.

Specific example 3

The preparation method of the amorphous boron carbide for catalytic graphitization, provided by the embodiment of the invention, specifically comprises the following steps:

1. weighing 3 groups of 5g B respectively₂O₃+3g of semi-coke samples, marked as samples #1, #2 and #3, fully and uniformly mixing the semi-coke samples according to the steps, then moving the reactant #1 into a tube furnace for heating, introducing argon for 20-30 min before heating to remove air in a quartz tube, and then controlling the flow of the argon to be minimum to form an argon protective atmosphere;

2. setting a heating program, heating to 800 ℃ at a heating rate of 10 ℃/min, keeping the temperature for 1h, and then slowly cooling the sample to room temperature along with the furnace to obtain black blocky amorphous boron carbide at 800 ℃.

Specific example 4

The embodiment of the present invention is different from embodiment 3 only in that: the temperature of the sample #2 was set at 1200 ℃ and the black bulk amorphous boron carbide at 1200 ℃ was obtained under the same conditions as in example 3.

Specific example 5

The inventive examples differ from examples 3 and 4 only in that: the temperature of the #3 sample was set to 1500 ℃ and other experimental conditions were the same as in example 3 or 4, and black bulk 1500 ℃ amorphous boron carbide was obtained.

Specific example 6

The method for preparing the artificial graphite by catalyzing graphitization by the amorphous boron carbide at 800 ℃ prepared in the embodiment 3 specifically comprises the following steps:

firstly, crushing blocky amorphous boron carbide, and then putting the blocky amorphous boron carbide into a ball milling tank for ball milling, wherein the ball-material ratio is 10:1, ball-milling for 3 hours at the rotating speed of 450r/min, and controlling the particle size of the ball-milling to be 1-3 mu m so that the particle size of the ball-milling is smaller than that of the carbon-based material;

weighing 4 groups of semicoke, wherein each group is 5g in weight, respectively weighing 800 ℃ amorphous boron carbide according to 0%, 10%, 15% and 20% of the weight of the semicoke, and putting the amorphous boron carbide and each group of semicoke into a mixer together for mixing for 1h to obtain a uniformly mixed composite raw material;

after the material mixing is finished, respectively taking 2g of the mixture from each group, transferring the mixture into a graphite crucible, and making corresponding marks; putting the prepared reactant into a vertical high-temperature graphitization furnace for heat treatment;

and (3) argon is used as the heat treatment atmosphere, after the vacuum pumping in the furnace is finished, the air flow is kept to be minimum, a heating program is set, the temperature starts to rise automatically after 1200 ℃, the heating rate is 10 ℃/min, the temperature is kept for 1h after the temperature rises to 2800 ℃, and then the sample is cooled to the room temperature along with the furnace, so that the artificial graphite material can be obtained.

The artificial graphite material prepared in the embodiment is prepared into an electrode, and the electrode and a lithium sheet are assembled into a half cell to carry out charge and discharge performance tests on the half cell, and as can be seen from the cycle performance of figure 1, the half coke without 800 ℃ amorphous boron carbide shows extremely low cell capacity after being graphitized at 2800 ℃ and kept warm for one hour, and when the half coke is charged and discharged at 0.5C multiplying power, the maximum charge specific capacity is only 238.7mAh g^-1With a catalystThe content is increased, and the capacity of the semi-coke after graphitization is obviously improved. After 10 percent, 15 percent and 20 percent of the catalyst are respectively added, the average specific capacity can reach 279.3mAh g respectively when the catalyst is charged and discharged at the multiplying power of 0.5C^-1、306.0mAh g^-1And 347.9mAh g^-1(ii) a Compared with the graphite without the catalyst, the specific capacity of the graphite can be improved by 109.2mAh g to the maximum extent^-1The expectation of the invention is reached.

From the first charge-discharge curve of fig. 2, the capacity is also significantly improved, and the first coulombic efficiency is improved to a certain extent, the first coulombic efficiency of the graphite electrode without the catalyst is 74.5%, and the first coulombic efficiencies of the graphite electrode with the catalysts of 10%, 15% and 20% are respectively 80.5%, 78.7% and 81.5%, so that the catalyst can improve the first coulombic efficiency of the graphite cathode to a certain extent, and the expectation of the invention is reached.

From the rate performance of the battery in fig. 3, the improvement of the semicoke capacity of the catalyst is consistent with the result of the cycle performance test, and the amorphous boron carbide can obviously improve the semicoke capacity.

Specific example 7:

the embodiment of the present invention is different from embodiment 6 in that: the temperature for catalyzing graphitization is set to be 2500 ℃, other conditions are the same as those in the example 6, and the artificial graphite material catalyzed by amorphous boron carbide at 800 ℃ below 2500 ℃ is finally obtained.

The artificial graphite material prepared in the example of the invention and the artificial graphite material prepared without adding the catalyst in the example 4 were made into electrodes, and assembled into a half cell for performance test.

As can be seen from the comparison of the cycle performance in FIG. 4, the average capacity of the original semicoke after the graphitization and heat preservation at 2800 ℃ for one hour is 232.3mA h g-1 at 0.5C for about 100 cycles, while the average capacity of the original semicoke after the addition of 15% of 800 ℃ amorphous boron carbide, the graphitization and heat preservation at 2500 ℃ for one hour, the charge and discharge under the same conditions are realized, and the average capacity is 296.9mA h g^-1Namely, after the graphitization temperature is reduced by 300 ℃, the specific capacity can be improved by 64.6mA h g^-1. This means thatThe semicoke achieves higher graphitization degree at lower temperature, namely lowers graphitization temperature, and the invention is expected.

As can be seen from the first charge-discharge curve of the battery in fig. 5, after the temperature is reduced by 300 ℃, the electrode capacity with 15% of 800 ℃ amorphous boron carbide added is obviously improved, and the first secondary discharge efficiency is 79.4%, compared with graphite without catalyst, the first coulombic efficiency is slightly improved, which also indicates that the semicoke achieves higher graphitization degree at lower temperature, and reaches the expectation of the present invention.

Fig. 6 is a comparison graph of the charge and discharge performance of the two batteries under different multiplying powers, and it is also proved that the graphitization temperature of the catalyst is reduced after 15% of 800 ℃ amorphous boron carbide is added, but the improvement of the multiplying power performance of the battery is not obvious from the graph.

Specific example 8

The invention relates to a preparation method of amorphous boron carbide, which comprises the following steps:

uniformly mixing a pre-selected carbon source with a boron source to obtain uniformly mixed powder;

and heating the uniformly mixed powder to 800 ℃ at a heating rate of 10 ℃/min under a protective atmosphere, preserving the heat for 5 hours, and cooling to room temperature to prepare the amorphous boron carbide.

The boron source is diboron trioxide; anthracite is selected as the carbon source. During mixing, the mass ratio of the carbon reducing agent to the boron oxide is 0.6, and the protective atmosphere is argon.

Specific example 9

The invention relates to a preparation method of amorphous boron carbide, which comprises the following steps:

uniformly mixing a pre-selected carbon source with a boron source to obtain uniformly mixed powder;

and heating the uniformly mixed powder to 1200 ℃ at a heating rate of 10 ℃/min under a protective atmosphere, preserving the heat for 1h, and cooling to room temperature to prepare the amorphous boron carbide.

The boron source is selected from diboron trioxide and boric acid; the carbon source is selected from anthracite, semicoke and petroleum coke. During mixing, the mass ratio of the carbon reducing agent to the boron oxide is 0.6, and the protective atmosphere is nitrogen.

Detailed description of example 10

The invention relates to a preparation method of amorphous boron carbide, which comprises the following steps:

uniformly mixing a pre-selected carbon source with a boron source to obtain uniformly mixed powder;

and heating the uniformly mixed powder to 1500 ℃ under the protective atmosphere, preserving the heat for 3 hours, and cooling to room temperature to prepare the amorphous boron carbide.

The boron source is boric acid; the carbon source is selected from semi-coke. During mixing, the mass ratio of the carbon reducing agent to the boron oxide is 0.6, and the protective atmosphere is nitrogen.

Specific example 11

The application of the amorphous boron carbide prepared by the preparation method is used for catalyzing the graphitization of the carbon-based material; the step of catalyzing the graphitization of the carbon-based material specifically comprises the following steps of:

ball-milling amorphous boron carbide and a carbon-based material, and uniformly mixing to obtain mixed powder;

and heating the mixed powder to 2500 ℃ under the protective atmosphere, preserving the heat for 10 hours, and cooling to room temperature to obtain the artificial graphite material. In the mixed powder, the grain diameter of amorphous boron carbide is 1 mu m; the particle size of the carbon-based material is 5 μm.

Detailed description of example 12

The application of the amorphous boron carbide prepared by the preparation method is used for catalyzing the graphitization of the carbon-based material; the step of catalyzing the graphitization of the carbon-based material specifically comprises the following steps of:

ball-milling amorphous boron carbide and a carbon-based material, and uniformly mixing to obtain mixed powder;

and heating the mixed powder to 2600 ℃ under a protective atmosphere, preserving the heat for 5 hours, and cooling to room temperature to obtain the artificial graphite material. In the mixed powder, the grain diameter of amorphous boron carbide is between 2 μm; the particle size of the carbon-based material is between 10 μm.

Specific example 13

The application of the amorphous boron carbide prepared by the preparation method is used for catalyzing the graphitization of the carbon-based material; the step of catalyzing the graphitization of the carbon-based material specifically comprises the following steps of:

ball-milling amorphous boron carbide and a carbon-based material, and uniformly mixing to obtain mixed powder;

and heating the mixed powder to 2800 ℃ under a protective atmosphere, preserving the heat for 1h, and cooling to room temperature to obtain the artificial graphite material. In the mixed powder, the grain diameter of amorphous boron carbide is between 3 μm; the particle size of the carbon-based material is between 15 μm.

Finally, it should be noted that: the above embodiments are only for illustrating the technical solutions of the present invention and not for limiting the same, and although the present invention is described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: modifications and equivalents may be made to the embodiments of the invention without departing from the spirit and scope of the invention, which is to be covered by the claims.