High-performance coal pitch-based supercapacitor electrode material and preparation method thereof

Abstract

The invention relates to the technical field of capacitor electrode material preparation, and particularly discloses a high-performance coal pitch-based supercapacitor electrode material and a preparation method thereof. The preparation method of the electrode material comprises the following steps: mixing asphalt, an activating agent and a template agent, and carrying out ball milling treatment to obtain a first mixture; and carrying out heat treatment on the first mixture in an inert atmosphere, and then washing with a weak acid solution to obtain the electrode material with uniform pores. The activating agent and the template agent are synergistically mixed with the asphalt for pore forming, so that the pore structure of the electrode material can be accurately regulated and controlled, and the electrode material with uniform pore distribution and excellent electrical properties is obtained; meanwhile, the preparation method disclosed by the invention has the characteristics of simple process and environmental friendliness. The technical problems that an existing coal pitch-based capacitor carbon material is small in specific surface area, uneven and uncontrollable in pore structure, tedious in preparation process and not environmentally friendly are solved.

Description

A high-performance coal tar pitch-based supercapacitor electrode material and its preparation method Technical Field

[0001] This invention relates to the field of capacitor electrode material preparation technology, and in particular to a high-performance coal tar pitch-based supercapacitor electrode material and its preparation method. Background Technology

[0002] As a novel energy storage device, the performance of supercapacitors hinges on their electrode materials. High-performance coal tar pitch-based supercapacitor electrode materials have become the preferred choice due to their high specific surface area, excellent conductivity, and electrochemical stability. Currently, commercially available porous carbon electrode materials mostly use coconut shells and resins as precursors, which presents challenges such as high raw material costs and limited sourcing, hindering the large-scale deployment of supercapacitors in large-scale energy storage systems.

[0003] Coal tar pitch, a byproduct of coal tar processing, is high in carbon, widely available, and inexpensive, making it an excellent precursor for preparing low-cost carbon materials with significant application potential in the field of capacitor carbon. However, carbon materials obtained by direct carbonization of coal tar pitch suffer from defects such as low specific surface area and unreasonable pore structure, failing to meet the requirements of high-performance supercapacitors. Activation modification is necessary to optimize the pore structure. Existing activation technologies are mainly divided into physical activation and chemical activation methods. Chemical activation uses highly corrosive reagents such as KOH and NaOH as activators, which can increase specific surface area, but suffers from severe equipment corrosion, significant environmental pollution, and complex post-processing. Physical activation uses gases such as water vapor and CO2, which are environmentally friendly, but suffer from high activation temperatures, low efficiency, and difficulty in controlling pore size distribution. Furthermore, surface oxidation modification can introduce oxygen-containing functional groups to improve performance, but it is mostly carried out at high temperatures, resulting in a violent and difficult-to-control reaction, which can easily damage the carbon skeleton or lead to uneven distribution of functional groups.

[0004] In summary, existing technologies still have many technical bottlenecks, and there is an urgent need to develop coal tar pitch-based high-performance capacitor carbon preparation technology that combines high specific surface area, controllable and adjustable pore structure, green and economical preparation process, simple process, and easy industrialization. Summary of the Invention

[0005] In view of this, the purpose of this invention is to provide a high-performance coal tar pitch-based supercapacitor electrode material and its preparation method, which solves the technical problems of existing coal tar pitch-based capacitor carbon materials, such as small specific surface area, non-uniform and uncontrollable pore structure, complicated preparation process and lack of environmentally friendly properties.

[0006] To achieve the above-mentioned technical objectives, this invention provides a method for preparing high-performance coal tar pitch-based supercapacitor electrode materials, comprising the following steps:

[0007] Step S1: Mix asphalt, activator, and template agent, and then ball mill to obtain the first mixture;

[0008] Step S2: The first mixture is heat-treated in an inert atmosphere to obtain a carbide;

[0009] Step S3: The carbide is washed sequentially with a weak acid solution and water until the washing solution is neutral, thereby obtaining a high-performance coal tar pitch-based supercapacitor electrode material.

[0010] Further, the mass ratio of asphalt, activator and template agent is 1:(1-6):(1-8); in step S2, the heat treatment temperature is 600-1000 ℃ and the heat treatment time is 1-3 h.

[0011] Furthermore, the first mixture also includes phenolic resin, with a mass ratio of phenolic resin to asphalt of (1-10):1.

[0012] Furthermore, the first mixture also includes phenolic resin and soluble iron salt, with the mass ratio of phenolic resin, soluble iron salt and asphalt being (10-100):(1-2):10.

[0013] Furthermore, the first mixture also includes iron ion chelated phenolic resin, with the mass ratio of iron ion chelated phenolic resin to asphalt being (1-10):1; the preparation method of iron ion chelated phenolic resin is as follows: phenolic resin, soluble iron salt, and solvent are mixed evenly, and the mixture is kept at 40-80℃ for 1-4 hours to obtain a solid phase, which is iron ion chelated phenolic resin; the mass ratio of phenolic resin to soluble iron salt is (10-100):1.

[0014] Furthermore, the first mixture also includes iron ion chelated phenolic resin-derived carbon material, with the mass ratio of iron ion chelated phenolic resin-derived carbon material to asphalt being (1-10):1; the preparation method of iron ion chelated phenolic resin-derived carbon material is as follows: phenolic resin, soluble iron salt, and solvent are mixed evenly and reacted at 40-80℃ for 1-4 hours to obtain a solid phase, which is iron ion chelated phenolic resin; the iron ion chelated phenolic resin is calcined to obtain iron ion chelated phenolic resin-derived carbon material; the mass ratio of phenolic resin to soluble iron salt is (10-100):1.

[0015] Furthermore, it also includes a directional oxidation step; the directional oxidation step is as follows: dispersing the high-performance coal tar pitch-based supercapacitor electrode material in water to form a suspension, placing the suspension inside a plasma reactor, and oxidizing it at 25–75 °C for 10–60 min.

[0016] Furthermore, iron salts include at least one of ferric nitrate, ferric chloride, and ferric sulfate.

[0017] Furthermore, the asphalt includes at least one of ordinary coal tar pitch, modified asphalt, oxidized asphalt, and mesophase asphalt; and / or, the activator includes at least one of KOH, NaOH, ZnCl2, and NaCl; and / or, the template agent includes at least one of MgO, CaO, CaCO3, and ZnO.

[0018] This invention provides a high-performance coal tar pitch-based supercapacitor electrode material, which is obtained by a method for preparing high-performance coal tar pitch-based supercapacitor electrode materials.

[0019] In summary, this invention provides a method for preparing a high-performance coal tar pitch-based supercapacitor electrode material, comprising the following steps: mixing pitch, an activator, and a template agent, followed by ball milling to obtain a first mixture; heat-treating the first mixture under an inert atmosphere to obtain a carbide; and washing the carbide sequentially with a weak acid solution and water until the washing solution is neutral, thereby obtaining the high-performance coal tar pitch-based supercapacitor electrode material. This invention achieves precise control of the pore structure of the electrode material by synergistically mixing the activator and template agent with pitch to create pores, resulting in an electrode material with uniform pore distribution and excellent electrical properties. Furthermore, the preparation method of this invention is simple, convenient, and environmentally friendly, requiring neither highly corrosive reagents nor harsh reaction conditions such as high temperatures.

[0020] Compared with existing technologies, the high-performance coal tar pitch-based supercapacitor electrode material prepared by this invention has both high specific surface area and uniform pore structure, exhibiting excellent charge and discharge performance and high capacitance, which can efficiently match the electrode application requirements of high-performance supercapacitors. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 is a scanning electron microscope image of the high-performance coal tar pitch-based supercapacitor electrode materials provided in Examples 1, 2, and 3;

[0023] Figure 2 shows the X-ray diffraction patterns of the high-performance coal tar pitch-based supercapacitor electrode materials provided in Examples 1, 2, and 3.

[0024] Figure 3 shows the Raman spectra of the high-performance coal tar pitch-based supercapacitor electrode materials provided in Examples 1, 2, and 3.

[0025] Figure 4 shows the cyclic voltammetry curves of button cells assembled from the high-performance coal tar pitch-based supercapacitor electrode materials provided in Examples 1, 2, and 3.

[0026] Figure 5 shows the constant current charge-discharge curves of the button batteries assembled with the high-performance coal tar pitch-based supercapacitor electrode materials provided in Examples 1, 2, and 3.

[0027] Figure 6 shows the constant current charge-discharge curves of the button batteries assembled with the high-performance coal tar pitch-based supercapacitor electrode materials provided in Examples 4 and 5.

[0028] Figure 7 shows the constant current charge-discharge curves of the button cell assembled with the high-performance coal tar pitch-based supercapacitor electrode materials provided in Examples 4, 6, and 7.

[0029] Figure 8 shows the constant current charge-discharge curves of button batteries assembled from the high-performance coal tar pitch-based supercapacitor electrode materials provided in Examples 7 and 8. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments in this specification, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection claimed by the present invention.

[0031] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," indicating orientation or positional relationships, are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0032] Unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances. Furthermore, there are no particular restrictions on the source of all raw materials used in this invention; they can be purchased commercially or prepared using conventional methods well known to those skilled in the art.

[0033] This invention provides a method for preparing a high-performance coal tar pitch-based supercapacitor electrode material, comprising the following steps:

[0034] Step S1: Mix asphalt, activator, and template agent, and then ball mill to obtain the first mixture;

[0035] Step S2: The first mixture is heat-treated in an inert atmosphere to obtain a carbide;

[0036] Step S3: The carbide is washed sequentially with a weak acid solution and water until the washing solution is neutral, thereby obtaining a high-performance coal tar pitch-based supercapacitor electrode material.

[0037] In some embodiments, the mass ratio of asphalt, activator, and template agent is 1:(1-6):(1-8); in step S2, the heat treatment temperature is 600-1000 °C, and the heat treatment time is 1-3 h. In some preferred embodiments, the heat treatment temperature is 700-900 °C.

[0038] In some specific embodiments, the inert gas used in the inert atmosphere is at least one of nitrogen or argon. The weak acid solution is a dilute hydrochloric acid solution with a concentration of 0.5–6 mol / L. In some specific embodiments, after washing, the high-performance coal tar pitch-based supercapacitor electrode material can be subjected to centrifugation and drying operations in sequence: centrifugation is performed at a speed of 8000–11000 r / min, with a single centrifugation time of 3–10 min, and repeated 3–6 times for dehydration; after centrifugation, drying treatment is performed at a drying temperature of 60–120 ℃ for a drying time of 3–12 h.

[0039] In some embodiments, the first mixture further includes phenolic resin, wherein the mass ratio of phenolic resin to asphalt is (1-10):1.

[0040] It should be noted that by introducing phenolic resin as a composite carbon source, it produces a synergistic effect with coal tar pitch during the high-temperature carbonization process: the rigid carbon skeleton formed by phenolic resin can effectively inhibit the excessive melting and shrinkage of coal tar pitch, playing a supporting role, thereby jointly constructing a more stable and developed multi-level pore structure, providing an efficient transport path for electrolyte ions.

[0041] In some embodiments, the first mixture further includes phenolic resin and soluble iron salt, wherein the mass ratio of phenolic resin, soluble iron salt and asphalt is (10-100):(1-2):10. In some embodiments, the first mixture further includes iron ion chelated phenolic resin, wherein the mass ratio of iron ion chelated phenolic resin to asphalt is (1-10):1; the iron ion chelated phenolic resin is prepared by mixing phenolic resin, soluble iron salt and solvent evenly, and reacting at 40-80°C for 1-4 hours, and the resulting solid is iron ion chelated phenolic resin; the mass ratio of phenolic resin and soluble iron salt is (10-100):1. In some embodiments, the first mixture further includes an iron-chelated phenolic resin-derived carbon material, wherein the mass ratio of the iron-chelated phenolic resin-derived carbon material to pitch is (1-10):1; the preparation method of the iron-chelated phenolic resin-derived carbon material is as follows: phenolic resin, soluble iron salt, and solvent are mixed evenly and reacted at 40-80°C for 1-4 hours to obtain a solid phase, which is an iron-chelated phenolic resin; the iron-chelated phenolic resin is calcined to obtain the iron-chelated phenolic resin-derived carbon material; the mass ratio of phenolic resin to soluble iron salt is (10-100):1. In some embodiments, the directional oxidation step is as follows: high-performance coal tar pitch-based supercapacitor electrode material is dispersed in water to form a suspension, the suspension is placed inside a plasma reactor, and oxidized at 25-75°C for 10-60 minutes.

[0042] In some embodiments, the parameters of the plasma reactor are: power of 150-600W, working pressure of 20-100 Pa, reactant gas of oxygen and / or air, and reactant gas flow rate of 20-100 sccm.

[0043] It should be noted that plasma-directed oxidation modification introduces abundant oxygen-containing functional groups (such as hydroxyl, carboxyl, and carbonyl groups) onto the surface of carbon materials. This not only improves the wettability and electrolyte compatibility of the materials, but also contributes additional specific capacity through the pseudocapacitive effect. At the same time, it maintains the high specific surface area and excellent pore structure characteristics of the materials, further enhancing the comprehensive electrochemical performance of the electrode materials.

[0044] In some embodiments, the iron salt includes at least one of ferric nitrate, ferric chloride, and ferric sulfate.

[0045] In some specific embodiments, the iron salt is selected from at least one of Fe(NO3)3·9H2O, FeCl3·6H2O, and Fe2(SO4)3·7H2O; more preferably, the iron salt is Fe(NO3)3.

[0046] In some embodiments, the asphalt includes at least one of ordinary coal tar pitch, modified asphalt, oxidized asphalt, and mesophase asphalt; and / or, the activator includes at least one of KOH, NaOH, ZnCl2, and NaCl; and / or, the template agent includes at least one of MgO, CaO, CaCO3, and ZnO.

[0047] This invention provides a high-performance coal tar pitch-based supercapacitor electrode material, obtained using a method for preparing high-performance coal tar pitch-based supercapacitor electrode materials. The applicant further provides the following specific embodiments to describe the invention. It should be noted that these embodiments are merely descriptive and do not limit the invention in any way. Embodiment 1

[0048] This embodiment provides a method for preparing a high-performance coal tar pitch-based supercapacitor electrode material, including the following steps:

[0049] Step S1, Premixing: Mix asphalt, activator and template agent in a mass ratio of 1:4:6, and ball mill for 0.5 hours until uniformly mixed to obtain the first mixture;

[0050] Step S2, carbonization: Under an inert atmosphere, the first mixture is heated to 800 ℃ at a heating rate of 5 ℃ / min, and heat-treated at 800 ℃ for 1 h to obtain carbides.

[0051] Step S3, Washing: After the carbide cools, it is placed in a 3 mol / L dilute hydrochloric acid solution with a liquid-to-solid volume ratio of 10:1 and ultrasonically washed for 10 minutes at a power density of 100 W / L and a temperature of 25℃. Then, solid-liquid separation is performed, and the solid phase is transferred to deionized water. Intermittent ultrasonic rinsing is performed under the same ultrasonic power conditions, with each rinse lasting 5 minutes. The water is changed repeatedly until the washing solution is neutral. Then, it is centrifuged at 8000 r / min for 5 minutes and repeated 4 times. The solid phase is dried at 60℃ for 12 hours to obtain a high-performance coal tar pitch-based supercapacitor electrode material.

[0052] Step S4, Directional oxidation: The high-performance coal tar pitch-based supercapacitor electrode material is dispersed in deionized water to form a dispersion. The dispersion is placed inside a plasma reactor, and the temperature of the dispersion is controlled at 40 °C. Then, oxygen is introduced into the plasma reactor at a flow rate of 30 sccm. The reactor is treated for 15 min at a power of 250 W and a chamber pressure of 60 Pa. Subsequently, the dispersion is subjected to solid-liquid separation, and the solid phase is dried to obtain the directionally oxidized high-performance coal tar pitch-based supercapacitor electrode material.

[0053] Example 2

[0054] This embodiment provides a method for preparing a high-performance coal tar pitch-based supercapacitor electrode material. The difference from Embodiment 1 is that in step S4, the temperature of the dispersion is 20 °C. (Example 3)

[0055] This embodiment provides a method for preparing a high-performance coal tar pitch-based supercapacitor electrode material, which differs from Embodiment 1 in that: in step S4, the temperature of the dispersion is 80 ℃.

[0056] Example 4

[0057] This embodiment provides a method for preparing a high-performance coal tar pitch-based supercapacitor electrode material. The difference from Embodiment 2 is that it also includes phenolic resin. The specific preparation steps are as follows:

[0058] Step S1, Premixing: Mix asphalt, activator, template agent and phenolic resin in a mass ratio of 1:4:6:3, and ball mill for 0.5 hours until uniformly mixed to obtain the first mixture;

[0059] Step S2, carbonization: Under an inert atmosphere, the first mixture is heated to 800 ℃ at a heating rate of 5 ℃ / min, and heat-treated at 800 ℃ for 1 h to obtain carbides.

[0060] Step S3, washing: After the carbide cools down, the carbide is washed with 3 mol / L dilute hydrochloric acid solution and deionized water in sequence until the filtrate is neutral. Then, it is centrifuged at 8000 r / min for 5 min and the centrifugation is repeated 4 times. The solid phase is dried at 60℃ for 12 h to obtain high-performance coal tar pitch-based supercapacitor electrode material.

[0061] Step S4, Directional oxidation: The high-performance coal tar pitch-based supercapacitor electrode material is dispersed in deionized water to form a dispersion. The dispersion is placed inside a plasma reactor, and the temperature of the dispersion is controlled at 40 °C. Then, oxygen is introduced into the plasma reactor at a flow rate of 30 sccm. The reactor is treated for 15 min at a power of 250 W and a chamber pressure of 60 Pa. Subsequently, the dispersion is subjected to solid-liquid separation, and the solid phase is dried to obtain the directionally oxidized high-performance coal tar pitch-based supercapacitor electrode material.

[0062] Example 5

[0063] This embodiment provides a method for preparing a high-performance coal tar pitch-based supercapacitor electrode material. The difference from Embodiment 4 is that directional oxidation was not performed. The specific preparation steps are as follows:

[0064] Step S1: Mix asphalt, activator, template agent, and phenolic resin in a mass ratio of 1:4:6:3, and ball mill for 0.5 hours until homogeneous to obtain the first mixture.

[0065] Step S2: Under an inert atmosphere, the first mixture is heated to 800 °C at a heating rate of 5 °C / min, and heat-treated at 800 °C for 1 hour to obtain carbides.

[0066] Step S3: After the carbide cools down, it is washed with 3 mol / L dilute hydrochloric acid solution and deionized water in sequence until the filtrate is neutral. Then, it is centrifuged at 8000 r / min for 5 min, and the centrifugation is repeated 4 times. The solid phase is dried at 60℃ for 12 h to obtain high-performance coal tar pitch-based supercapacitor electrode material.

[0067] Example 6

[0068] This embodiment provides a method for preparing a high-performance coal tar pitch-based supercapacitor electrode material, which differs from Embodiment 2 in that it also includes phenolic resin and ferric nitrate nonahydrate; the specific preparation steps are as follows:

[0069] Step S1, Premixing: Asphalt, activator, template agent, phenolic resin and ferric nitrate nonahydrate are mixed in a mass ratio of 1:4:6:3:0.15, ball-milled for 0.5 hours, and mixed evenly to obtain the first mixture;

[0070] Step S2, carbonization: Under an inert atmosphere, the first mixture is heated to 800 ℃ at a heating rate of 5 ℃ / min, and heat-treated at 800 ℃ for 1 h to obtain carbides.

[0071] Step S3, washing: After the carbide cools down, the carbide is washed with 3 mol / L dilute hydrochloric acid solution and deionized water in sequence until the filtrate is neutral. Then, it is centrifuged at 8000 r / min for 5 min and the centrifugation is repeated 4 times. The solid phase is dried at 60℃ for 12 h to obtain high-performance coal tar pitch-based supercapacitor electrode material.

[0072] Step S4, Directional oxidation: The high-performance coal tar pitch-based supercapacitor electrode material is dispersed in deionized water to form a dispersion. The dispersion is placed inside a plasma reactor, and the temperature of the dispersion is controlled at 40 °C. Then, oxygen is introduced into the plasma reactor at a flow rate of 30 sccm. The reactor is treated for 15 min at a power of 250 W and a chamber pressure of 60 Pa. Subsequently, the dispersion is subjected to solid-liquid separation, and the solid phase is dried to obtain the directionally oxidized high-performance coal tar pitch-based supercapacitor electrode material.

[0073] Example 7

[0074] This embodiment provides a method for preparing a high-performance coal tar pitch-based supercapacitor electrode material, including the following steps:

[0075] Step S1, Preparation of iron ion chelated phenolic resin: Dissolve phenolic resin in ethanol to prepare a 20% (w / w) solution; continuously stir the solution and slowly add ferric nitrate nonahydrate to the solution, reacting under a 60°C water bath to allow Fe ions to chelate. 3+ The phenolic hydroxyl groups of the phenolic resin are fully coordinated; then the ethanol is removed by rotary evaporation to obtain a solid iron ion chelated phenolic resin; wherein the mass ratio of phenolic resin to ferric nitrate nonahydrate is 20:1.

[0076] Step S2, Premixing: Mix asphalt, activator, template agent, and iron ion chelating phenolic resin in a mass ratio of 1:4:6:3, and ball mill for 0.5 hours until uniformly mixed to obtain the first mixture;

[0077] Step S3, carbonization: Under an inert atmosphere, the first mixture is heated to 800 ℃ at a heating rate of 5 ℃ / min, and heat-treated at 800 ℃ for 1 h to obtain carbides.

[0078] Step S4, washing: After the carbide cools down, the carbide is washed with 3 mol / L dilute hydrochloric acid solution and deionized water in sequence until the filtrate is neutral. Then, it is centrifuged at 8000 r / min for 5 min and the centrifugation is repeated 4 times. The solid phase is dried at 60℃ for 12 h to obtain high-performance coal tar pitch-based supercapacitor electrode material.

[0079] Step S5, Directional oxidation: The high-performance coal tar pitch-based supercapacitor electrode material is dispersed in deionized water and placed inside a plasma reactor. The water temperature is controlled at 40 ℃, and oxygen is introduced into the plasma reactor at a flow rate of 30 sccm. The reactor is treated for 15 min at a power of 250 W and a chamber pressure of 60 Pa. Subsequently, the dispersion is subjected to solid-liquid separation, and the solid phase is dried to obtain the directionally oxidized high-performance coal tar pitch-based supercapacitor electrode material.

[0080] Example 8

[0081] This embodiment provides a method for preparing a high-performance coal tar pitch-based supercapacitor electrode material, including the following steps:

[0082] Step S1, Preparation of iron ion chelated phenolic resin: Dissolve phenolic resin in ethanol to prepare a 20% (w / w) solution; continuously stir the solution and slowly add ferric nitrate nonahydrate to the solution, reacting under a 60°C water bath to allow Fe ions to chelate. 3+The phenolic hydroxyl groups of the phenolic resin are fully coordinated; then the ethanol is removed by rotary evaporation to obtain a solid iron ion chelated phenolic resin; wherein the mass ratio of phenolic resin to ferric nitrate nonahydrate is 20:1.

[0083] Step S2, primary carbonization: Under nitrogen atmosphere protection, the iron ion chelated phenolic resin is heated to 800 ℃ at a heating rate of 5 ℃ / min and held for heat treatment for 1 h to obtain iron ion chelated phenolic resin derived carbon material.

[0084] Step S3, Premixing: Asphalt, activator, template agent, and iron ion chelated phenolic resin-derived carbon material are mixed in a mass ratio of 1:4:6:3, ball-milled for 0.5 hours, and mixed evenly to obtain the first mixture;

[0085] Step S4, secondary carbonization: Under an inert atmosphere, the first mixture is heated to 800 ℃ at a heating rate of 5 ℃ / min, and heat-treated at 800 ℃ for 1 h to obtain carbides.

[0086] Step S5, washing: After the carbide cools down, the carbide is washed with 3 mol / L dilute hydrochloric acid solution and deionized water in sequence until the filtrate is neutral. Then, it is centrifuged at 8000 r / min for 5 min and the centrifugation is repeated 4 times. The solid phase is dried at 60℃ for 12 h to obtain high-performance coal tar pitch-based supercapacitor electrode material.

[0087] Step S6, Directional Oxidation: The high-performance coal tar pitch-based supercapacitor electrode material was dispersed in deionized water and placed inside a plasma reactor. The water temperature was controlled at 40 °C, and oxygen was introduced into the plasma reactor at a flow rate of 30 sccm. The reactor was treated for 15 min at a power of 250 W and a chamber pressure of 60 Pa. Subsequently, solid-liquid separation was performed on the dispersion, and the solid phase was dried to obtain the directionally oxidized high-performance coal tar pitch-based supercapacitor electrode material. To compare the effects of different preparation conditions on the performance of the coal tar pitch-based supercapacitor electrode material, the electrode materials prepared in Examples 1-3 were characterized and analyzed. The electrode materials prepared in Examples 1-8 were assembled into button batteries, and their electrochemical performance was tested. The specific test methods are as follows:

[0088] Test method: Conductive carbon black, binder (specifically polytetrafluoroethylene, PTFE), and electrode materials (wherein, the electrode materials are: the high-performance coal tar pitch-based electrode materials with directional oxidation treatment provided in Examples 1-4 and 6-8, and the high-performance coal tar pitch-based electrode material without directional oxidation provided in Example 5) are weighed together with the conductive carbon black in a mass ratio of 3:1:6. Then, an appropriate amount of anhydrous ethanol and PTFE are added, and the mixture is stirred to form a uniform slurry. After the ethanol evaporates naturally, the slurry is pressed into sheets and further pressed onto the surface of the nickel foam current collector. After drying to remove residual solvent, a circular electrode with a diameter of 12 mm is obtained, with an active material surface loading of 1-4 mg / cm². 2 The button cell assembly then proceeded as follows: the positive electrode shell, gasket, positive electrode sheet, glass fiber separator, electrolyte (6 mol / L KOH solution), negative electrode sheet, gasket, spring sheet, and negative electrode shell were stacked sequentially, and finally sealed using a sealing machine to complete the assembly. Electrochemical performance tests were then conducted on the button cells to characterize the electrode material properties. Test results:

[0089] Figure 1 shows scanning electron microscope (SEM) images of the high-performance coal tar pitch-based supercapacitor electrode materials provided in Examples 1, 2, and 3. Example 1 exhibits a morphological characteristic of increased pore number and irregular shape; Example 2 forms a highly interconnected honeycomb-like porous framework structure with uniform pore distribution and a dense structure, which provides sufficient channels for electrolyte ion transport; Example 3 shows structural degradation, manifested as pore network collapse accompanied by signs of overactivation, presumably due to excessive reaction between oxygen plasma and the carbon matrix at high temperatures, which disrupts the stability of the carbon material framework. Therefore, it can be concluded that by controlling the temperature of the dispersion liquid to be greater than 20°C and less than 80°C during the directional oxidation process, high-performance coal tar pitch-based supercapacitor electrode materials with uniform pore distribution and a dense structure can be obtained.

[0090] Figure 2 shows the X-ray diffraction patterns of the high-performance coal tar pitch-based supercapacitor electrode materials provided in Examples 1, 2, and 3. All the XRD patterns of the high-performance coal tar pitch-based supercapacitor electrode materials show a broadened diffraction peak at approximately 21°, which is attributed to the (002) crystal plane of graphite carbon. Furthermore, with increasing oxygen plasma temperature, the full width at half maximum (FWHM) of the (002) crystal plane increases significantly. This is due to the introduction of porous defects and oxygen-containing functional groups, which disrupts the ordered arrangement of the carbon lattice.

[0091] Figure 3 shows the Raman spectra of the high-performance coal tar pitch-based supercapacitor electrode materials provided in Examples 1, 2, and 3. The spectra are at 1340 cm⁻¹. -1 and 1580 cm -1Two broadened and partially overlapping characteristic peaks appear nearby (originating from the in-plane vibrational modes of sp2 hybridized carbon atoms). The high ID / IG ratio indicates a high defect density and low graphitization order in the material. Studies show that increasing the oxidation temperature helps to introduce more structural defects, with this trend peaking at 40 °C, while the ID / IG value slightly decreases at 80 °C, indicating that excessively high temperatures may lead to partial degradation of the carbon framework.

[0092] Figure 4 shows the cyclic voltammetry curves of the coin cells assembled from the high-performance coal tar pitch-based supercapacitor electrode materials provided in Examples 1, 2, and 3. It can be seen that... At the scanning rate, the cyclic voltammetry curve area of ​​Example 2 is the largest, indicating that it has a higher specific capacitance, which is consistent with the effect of the dense and uniform porous structure of Example 2 on improving the capacitor performance.

[0093] Figure 5 shows the constant current charge-discharge curves of the button cells assembled from the high-performance coal tar pitch-based supercapacitor electrode materials provided in Examples 1, 2, and 3. In 6 M KOH electrolyte, the constant current charge-discharge curve of Example 2 exhibits a longer discharge time. and The capacitances at current densities are approximately and 81 F g -1 .

[0094] Figure 6 shows the constant current charge-discharge curves of the button cells assembled from the high-performance coal tar pitch-based supercapacitor electrode materials obtained in Examples 4 and 5. In 6 M KOH electrolyte, the constant current charge-discharge curve of Example 4 has a longer discharge time than that of Example 2, at 1 A g -1 At a current density of [value missing], the capacitance is approximately 93.6 F g. -1 This indicates that during the blending and carbonization of phenolic resin, the rigid framework of the phenolic resin can inhibit the excessive melting and ordering of asphalt at high temperatures, hindering the formation of large-scale graphite structures, thereby reducing pore collapse and increasing defects and active sites. This structural complementarity allows the capacitive carbon to maintain good conductivity while acquiring a more developed pore structure, thus effectively improving the capacitance of the carbon material. Compared with Example 4, the constant current charge-discharge curve of Example 5 shows a shorter discharge time, indicating that the directional oxidation treatment effectively ensures the surface chemical properties and cleanliness of the carbon material, playing a key role in improving the capacity of the carbon material.

[0095] Figure 7 shows the constant current charge-discharge curves of button cells assembled from the high-performance coal tar pitch-based supercapacitor electrode materials obtained in Examples 4, 6, and 7. In 6 M KOH electrolyte, the constant current charge-discharge curve of Example 7 has a longer discharge time than that of Examples 4 and 6, at 1 A g. -1 At a current density of approximately 171 F g, the capacitance is approximately 171 F g.-1 This indicates that, compared to physical mixing (Example 6), chelation modification (Example 7) enables the binding of metallic iron ions with phenolic resin at the molecular level, achieving highly uniform dispersion in the carbon matrix. This uniformity brings two major advantages in the subsequent carbonization process: First, it achieves uniformity in catalytic graphitization: the highly dispersed iron nanoparticles act as efficient catalytic sites during carbonization, inducing the formation of localized, interconnected graphite microcrystal networks around them, thereby significantly improving the overall electronic conductivity of the electrode material and reducing the internal resistance during charging and discharging. Second, it achieves uniformity in the pore-forming process: after acid washing removes the uniformly dispersed iron nanoparticles, uniformly distributed, interconnected mesopores and macropores remain. This hierarchical pore structure greatly optimizes the ion transport path, ensuring that electrolyte ions can still quickly reach the active surface at high current densities. Therefore, the longer discharge time of Example 7 in Figure 7 intuitively reflects its lower internal impedance and more efficient ion diffusion capability, a synergistic effect that is difficult to achieve with physical mixing methods.

[0096] Figure 8 shows the constant current charge-discharge curves of the button cells assembled from the high-performance coal tar pitch-based supercapacitor electrode materials obtained in Examples 7 and 8. In 6 M KOH electrolyte, the constant current charge-discharge curve of Example 8 has a shorter discharge time than that of Example 7, at 1 A g -1 At a current density of approximately 135 F g, the capacitance is approximately 135 F g. -1 This indicates that iron ion chelating phenolic resin plays an important role in optimizing the pore structure of carbon materials, while carbonized iron ion chelating phenolic resin is difficult to regulate the pore structure of carbon materials.

[0097] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. However, any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a high-performance coal tar pitch-based supercapacitor electrode material, characterized in that, Includes the following steps: Step S1: Mix asphalt, activator, and template agent, and ball mill to obtain a first mixture; Step S2: Heat treat the first mixture under an inert atmosphere to obtain a carbide; Step S3: Wash the carbide sequentially with a weak acid solution and water until the washing solution is neutral to obtain a high-performance coal tar pitch-based supercapacitor electrode material.

2. The method for preparing the high-performance coal tar pitch-based supercapacitor electrode material according to claim 1, characterized in that, The mass ratio of the asphalt, activator, and template agent is 1:(1-6):(1-8); in step S2, the heat treatment temperature is 600-1000 ℃, and the heat treatment time is 1-3 h.

3. The method for preparing the high-performance coal tar pitch-based supercapacitor electrode material according to claim 1, characterized in that, The first mixture also includes phenolic resin, wherein the mass ratio of phenolic resin to asphalt is (1-10):

1.

4. The method for preparing the high-performance coal tar pitch-based supercapacitor electrode material according to claim 1, characterized in that, The first mixture also includes phenolic resin and soluble iron salt, wherein the mass ratio of phenolic resin, soluble iron salt and asphalt is (10-100):(1-2):

10.

5. The method for preparing the high-performance coal tar pitch-based supercapacitor electrode material according to claim 1, characterized in that, The first mixture further includes iron ion chelating phenolic resin, wherein the mass ratio of the iron ion chelating phenolic resin to asphalt is (1-10):1; the iron ion chelating phenolic resin is prepared by mixing phenolic resin, soluble iron salt, and solvent evenly, and reacting at 40-80℃ for 1-4 hours to obtain a solid phase, which is iron ion chelating phenolic resin; wherein the mass ratio of the phenolic resin to soluble iron salt is (10-100):

1.

6. The method for preparing the high-performance coal tar pitch-based supercapacitor electrode material according to claim 1, characterized in that, The first mixture also includes an iron ion chelated phenolic resin-derived carbon material, wherein the mass ratio of the iron ion chelated phenolic resin-derived carbon material to asphalt is (1-10):1; the preparation method of the iron ion chelated phenolic resin-derived carbon material is as follows: phenolic resin, soluble iron salt, and solvent are mixed evenly and reacted at 40-80℃ for 1-4 hours to obtain a solid phase, which is an iron ion chelated phenolic resin; the iron ion chelated phenolic resin is calcined to obtain the iron ion chelated phenolic resin-derived carbon material; wherein the mass ratio of the phenolic resin to the soluble iron salt is (10-100):

1.

7. The method for preparing the high-performance coal tar pitch-based supercapacitor electrode material according to claim 1, characterized in that, It also includes a directional oxidation step; the directional oxidation step is as follows: the high-performance coal tar pitch-based supercapacitor electrode material is dispersed in water to form a suspension, the suspension is placed inside a plasma reactor, and oxidized at 25-75 °C for 10-60 min.

8. The method for preparing the high-performance coal tar pitch-based supercapacitor electrode material according to claims 4-6, characterized in that, The iron salt includes at least one of ferric nitrate, ferric chloride, and ferric sulfate.

9. The method for preparing the high-performance coal tar pitch-based supercapacitor electrode material according to claim 1, characterized in that: The asphalt includes at least one of ordinary coal tar pitch, modified asphalt, oxidized asphalt, and mesophase asphalt; and / or, the activator includes at least one of KOH, NaOH, ZnCl2, and NaCl; and / or, the template agent includes at least one of MgO, CaO, CaCO3, and ZnO.

10. A high-performance coal tar pitch-based supercapacitor electrode material, characterized in that, It is obtained by the preparation method described in any one of claims 1 to 9.

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