A high performance capacitor carbon material and preparation method thereof

Abstract

The invention discloses a method for preparing a high-performance capacitor carbon material, comprising: using calcium carbide as a precursor, first ball-milling it, and then calcining it in a nitrogen atmosphere; the calcination temperature is 500-700°C. The method overcomes the shortcomings of the existing etching using toxic gases such as chlorine, and the obtained capacitor carbon material can be used as an electrode material for a supercapacitor, showing excellent capacitance performance.

Description

Technical Field

[0001] The invention belongs to the field of porous carbon material preparation, and in particular relates to a high-performance capacitor carbon material and a preparation method thereof. Background Art

[0002] Supercapacitors are widely used in energy, telecommunications, military equipment, industrial production and other fields due to their outstanding advantages of high power density and long cycle life. Electrode materials are one of the key factors that determine the energy storage performance of supercapacitors; among them, porous carbon materials are the mainstream. The synthesis methods for preparing porous carbon materials include: high-temperature pyrolysis method, hydrothermal carbonization method, template method, etc. The above synthesis methods all have corresponding advantages, but there are also some technical problems that need to be overcome. For example, the high-temperature pyrolysis method requires extremely high temperatures, which places high demands on heating equipment and has high energy consumption.

[0003] Calcium carbide is a waste residue discharged from chemical industry production. Its main component, calcium carbide, has a high content of 2.22gcm -3 The actual density of calcium carbide is higher than that of calcium carbide. The calcium carbide-derived carbon material obtained with calcium carbide as a precursor has a rich pore structure and has attracted the attention of many researchers. Studies have found that by controlling the microstructure and surface chemistry of calcium carbide-derived carbon materials to prepare carbon materials with different compositions and structures, and using them as electrode materials, the energy storage performance of supercapacitors can be significantly improved. The method of preparing carbon materials with calcium carbide as raw material is most commonly used with chlorine as an etchant.

[0004] For example, Professor Wang Xianyou and others used a method to prepare nanoporous carbon materials by directly etching calcium carbide with chlorine at medium and low temperatures (Mater. Chem. Phys., 2008, 112, 461-465). This method uses freshly prepared chlorine and calcium carbide as raw materials, reacts at 100-600°C to obtain amorphous nanoporous carbon materials. The carbon material obtained by this preparation method has almost no silicon carbide impurities, and the entire reaction process is controllable. However, this method requires fresh chlorine for etching, which is extremely harmful to the environment and human body, and the electrochemical properties of the reaction product nanoporous carbon material are poor, and further research and optimization are needed. CN109985602A discloses a method for preparing oxygen-containing acetylene carbon materials by ball milling calcium carbide and carbon dioxide or carbonate. This method is to acid-wash, water-wash and dry the solid product after ball milling reaction of calcium carbide and carbon dioxide in certain proportions under certain conditions, and finally obtain a new type of oxygen-containing acetylene carbon material. The carbon material prepared by this method has the advantages of unique structure and excellent physical and chemical properties. However, this method uses carbon dioxide as a reaction product, the cost is relatively high, and a vacuum environment is required during the ball milling process. The preparation process is relatively cumbersome and not simple and easy to implement. Summary of the invention

[0005] Based on the above technical problems, the present invention provides a method for preparing high-performance capacitor carbon materials by calcining low-cost calcium carbide and nitrogen as raw materials. The method overcomes the shortcomings of the existing etching using toxic gases such as chlorine, and the obtained capacitor carbon material can be used as an electrode material for supercapacitors and exhibits excellent capacitance performance.

[0006] The specific scheme of the present invention is as follows:

[0007] The invention provides a method for preparing a high-performance capacitor carbon material, comprising: taking calcium carbide as a precursor, first subjecting it to ball milling treatment, and then calcining it in a nitrogen atmosphere; the calcination temperature is 500-700°C.

[0008] Preferably, the calcination time is 1-5 h.

[0009] Preferably, the calcination temperature is 600° C. and the calcination time is 3 h.

[0010] Preferably, the temperature is raised to the calcination temperature under a nitrogen atmosphere at a rate of 5 to 10° C. / min.

[0011] Preferably, the ball milling processing parameters include: ball milling speed 500-900r / min, ball milling time 15-24h, ball to material ratio 15-20:1.

[0012] Preferably, during ball milling, the ball milling beads and calcium carbide are weighed according to the ball-to-material ratio, the ball milling beads and calcium carbide are mixed under air conditions or under argon protection, and the ball milling jar is sealed. More preferably, the ball milling beads and calcium carbide are directly mixed in air and the ball milling jar is sealed.

[0013] Preferably, the method further comprises screening after the ball milling treatment and before the calcination treatment, through a 100-300 mesh sieve.

[0014] Preferably, the method further comprises washing the calcined material until the washing liquid is neutral, and drying.

[0015] The present invention also provides a high-performance capacitor carbon material, which is prepared by any of the above methods.

[0016] The beneficial effects of the present invention are:

[0017] The present invention provides a method for preparing high-performance capacitor carbon materials using calcium carbide and nitrogen as raw materials, which not only realizes the "waste-to-treasure" transformation of industrial waste residues and ensures the low cost of raw materials, but also avoids the pressure on environmental protection caused by the participation of toxic gases such as chlorine in the preparation process. The entire process is simple and easy, and can achieve kilogram-level scale-up preparation.

[0018] The capacitive carbon material obtained by the method has micropores, mesopores and macropores, with micropores being the main ones, and has a large specific surface area and high electrical conductivity. The carbon material is used as a supercapacitor electrode material to exhibit excellent capacitance performance, further improving the energy storage performance of the supercapacitor. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 The X-ray diffraction (XRD) diagrams of the capacitive carbon materials obtained in Examples 1, 3, and 4;

[0020] Figure 2 The scanning electron microscope (SEM) images of the capacitive carbon materials obtained in Examples 1, 3 and 4 are shown;

[0021] Figure 3 The N2 adsorption / desorption curves and pore size distribution diagrams of the capacitive carbon materials obtained in Examples 1, 3, and 4;

[0022] Figure 4 Cyclic voltammetry curves of the capacitor carbon materials obtained in Examples 1, 3, and 4 in 6 mol / L KOH electrolyte;

[0023] Figure 5 Cyclic voltammetry curves of the capacitive carbon materials obtained in Examples 1, 2 and Comparative Example 1 in 6 mol / L KOH electrolyte; DETAILED DESCRIPTION

[0024] The technical solutions of the present invention are described in detail below through specific embodiments. However, it should be clearly stated that these embodiments are for illustration only and are not to be construed as limiting the scope of the present invention.

[0025] Example 1

[0026] A high-performance capacitor carbon material, the preparation method of which comprises:

[0027] (1) Ball milling: Calcium carbide and ball milling beads were weighed at a mass ratio of 1:20 and placed in a vacuum-dried ball mill, directly mixed in air and sealed in the ball mill; ball milled at a speed of 800 r / min for 24 h using a planetary ball mill to obtain a black powder;

[0028] (2) Sieving: Pass the black powder through a 200-mesh sieve;

[0029] (3) Calcination treatment: Take an appropriate amount of black powder and place it in a porcelain boat. Put it in a tube furnace and heat it to 500°C at a rate of 5°C / min under a nitrogen atmosphere. Keep it at this temperature for 3 h and then cool it naturally to room temperature.

[0030] (4) Post-treatment: The calcined material is washed with a 3 mol / L hydrochloric acid solution, and then washed with deionized water and ethanol in small amounts and multiple times until the washing liquid becomes neutral, and then filtered, dried, and naturally cooled to room temperature to obtain a high-performance capacitor carbon material.

[0031] Example 2

[0032] A high-performance capacitor carbon material, the preparation method of which comprises:

[0033] (1) Ball milling: Calcium carbide and ball milling beads were weighed at a mass ratio of 1:20 and placed in a vacuum-dried ball mill. The calcium carbide and ball milling beads were mixed in a glove box protected by an argon atmosphere and the ball mill was sealed. The mixture was ball milled at a speed of 800 r / min for 24 h using a planetary ball mill to obtain a black powder.

[0034] (2) Sieving: Pass the black powder through a 200-mesh sieve;

[0035] (3) Calcination treatment: Take an appropriate amount of black powder and place it in a porcelain boat. Put it in a tube furnace and heat it to 500°C at a rate of 5°C / min under a nitrogen atmosphere. Keep it at this temperature for 3 h and then cool it naturally to room temperature.

[0036] (4) Post-treatment: The calcined material is washed with a 3 mol / L hydrochloric acid solution, and then washed with deionized water and ethanol in small amounts and multiple times until the washing liquid becomes neutral, and then filtered, dried, and naturally cooled to room temperature to obtain a high-performance capacitor carbon material.

[0037] Example 3

[0038] A high-performance capacitor carbon material, the preparation method of which is compared with that of Example 1, the only difference is that during the calcination treatment, the calcination temperature is changed from "500°C" to "600°C", and other methods and parameters are the same as those of Example 1.

[0039] Example 4

[0040] A high-performance capacitor carbon material, the preparation method of which is compared with that of Example 1, the only difference is that during the calcination treatment, the calcination temperature is changed from "500°C" to "700°C", and other methods and parameters are the same as those of Example 1.

[0041] Comparative Example 1

[0042] A capacitor carbon material, the preparation method of which comprises:

[0043] (1) Grinding and crushing: Place calcium carbide directly in a mortar and grind it with a grinding rod;

[0044] (2) Sieving: The crushed powder is passed through a 200-mesh sieve;

[0045] (3) Calcination treatment: Take an appropriate amount of sieved powder and place it in a porcelain boat. Put it into a tube furnace and heat it to 500°C at a rate of 5°C / min under nitrogen atmosphere, keep it at this temperature for 3 hours, and then cool it naturally to room temperature.

[0046] (4) Post-treatment: The calcined material is washed with a 3 mol / L hydrochloric acid solution, and then washed with deionized water and ethanol in small amounts and multiple times until the washing liquid becomes neutral, and then filtered, dried, and naturally cooled to room temperature to obtain a capacitor carbon material.

[0047] The capacitive carbon materials described in Examples 1-4 and Comparative Example 1 were used as electrode materials, 6 mol / L KOH solution was used as electrolyte, and PP / PE film was used as diaphragm to prepare 2032-type button-type supercapacitors. The capacitive carbon materials obtained in the above examples and comparative examples and the assembled 2032-type button-type supercapacitors were characterized and their related performances were tested, as follows:

[0048] Figure 1 : The X-ray diffraction (XRD) diagram of the capacitive carbon materials obtained in Examples 1, 3 and 4, wherein D, E and F correspond to Examples 1, 3 and 4, respectively. It can be seen that the carbon materials obtained in Examples 1, 3 and 4 all have broad peaks near 2θ=25° and 44°, corresponding to the characteristic peaks of diffraction of graphite carbon (002) and (101) crystal planes, indicating that the carbon materials obtained in Examples 1, 3 and 4 are all amorphous porous carbon materials.

[0049] Figure 2 The scanning electron microscope (SEM) images of the capacitive carbon materials obtained in Examples 1, 3 and 4, wherein a, b and c correspond to Examples 1, 3 and 4 respectively; it can be seen that the carbon material obtained in Example 3 is an aggregate of carbon nanoparticles with a more uniform morphology.

[0050] Figure 3 N2 adsorption / desorption curves and pore size distribution diagrams of the capacitive carbon materials obtained in Examples 1, 3 and 4, wherein a) is the N2 adsorption / desorption curve; b) is the pore size distribution diagram; D, E and F in the figure correspond to Examples 1, 3 and 4 respectively; it can be seen that the carbon materials obtained in Examples 1, 3 and 4 have micropores, mesopores and macropores, and the pore size distribution of Example 3 is mainly micropores, and the specific surface area is the largest.

[0051] Figure 4 The cyclic voltammetry curves of the capacitive carbon materials obtained in Examples 1, 3, and 4, wherein D, E, and F correspond to Examples 1, 3, and 4, respectively; it can be seen that compared with Examples 1 and 4, the carbon material obtained in Example 3 presents a rectangular shape at a scan rate of 100 mV / S and the rectangular area is the largest, indicating that the carbon material obtained in Example 3 has the highest specific capacitance and excellent rate performance;

[0052] Figure 5 The cyclic voltammetry curves of the capacitive carbon materials obtained in Examples 1, 2 and Comparative Example 1 in 6 mol / L KOH electrolyte, wherein A, B, and C correspond to Examples 1, 2 and Comparative Example 1, respectively; it can be seen that the carbon material obtained in Example 1 has the largest rectangular area at a scanning rate of 100 mV / S, indicating that the capacitive carbon material obtained by ball-milling and sieving calcium carbide in an air environment and then etching with N2 gas has higher specific capacitance and better electrochemical performance.

[0053] In summary, the capacitive carbon material obtained by etching calcium carbide with low-cost inert gas nitrogen in the present invention has the advantages of high capacitance, high rate performance, etc., and using it as a supercapacitor electrode material can greatly improve the energy storage performance of the supercapacitor, and can be applied to large-scale engineering machinery, wind turbines, new energy vehicles and other fields with high energy density requirements.

[0054] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for preparing a high-performance capacitor carbon material, characterized in that: include: Calcium carbide is used as a precursor, which is first ball-milled and then calcined in a nitrogen atmosphere; The calcination temperature is 500-700℃; the ball milling processing parameters include: ball milling speed 500-900r / min, ball milling time 15-24h, ball-to-material ratio 15-20:1; during ball milling, ball milling beads and calcium carbide are weighed respectively according to the ball-to-material ratio, the ball milling beads and calcium carbide are mixed under air conditions or argon protection, and the ball milling jar is sealed.

2. The method for preparing a high performance capacitor carbon material according to claim 1, characterized in that: The calcination time is 1-5h.

3. The method for preparing a high performance capacitor carbon material according to claim 1 or 2, characterized in that: The calcination temperature is 600°C and the calcination time is 3h.

4. The method for preparing a high performance capacitor carbon material according to any one of claims 1 or 2, characterized in that: The temperature was raised to the calcination temperature under a nitrogen atmosphere at a rate of 5 to 10°C / min.

5. The method for preparing a high performance capacitor carbon material according to any one of claims 1 or 2, characterized in that: It also includes screening after ball milling and before calcination, passing through a 100-300 mesh sieve.

6. The method for preparing a high performance capacitor carbon material according to any one of claims 1 or 2, characterized in that: The method also includes washing the calcined material until the washing liquid is neutral, and drying.

7. A high performance capacitor carbon material, characterized in that: The method is prepared by any one of claims 1 to 6.

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