High uniformity ultra-high pore volume carbon black and method for making same

Abstract

The application discloses high-uniformity super-high-pore-volume carbon black and a preparation method thereof, and belongs to the technical field of carbon material preparation. 60 @The method comprises the following steps: uniformly dispersing fullerenes in an aromatic hydrocarbon precursor to form a mixed solution; pyrolyzing and carbonizing under an inert atmosphere to form C 60 @The carbon black core-shell structure is formed by sequentially performing first-stage low-temperature oxidation and second-stage high-temperature oxidation treatment, selectively removing the fullerenes template to build uniform micropores, and finally performing hydrogen reduction treatment to obtain the product. Through the synergistic effect of the fullerenes molecular template and the gradient oxidation process, the prepared carbon black has a pore volume of greater than or equal to 2.86 cm<3> / g, a micropore volume proportion of greater than or equal to 86.5%, and a particle size distribution span (Span) of less than or equal to 0.87, and has high pore volume and high structural uniformity, and can be widely applied to high-end energy storage fields such as lithium-sulfur batteries and supercapacitors.

Description

Technical Field

[0001] This invention belongs to the field of carbon material preparation technology, and specifically relates to a highly uniform ultra-high pore volume carbon black and its preparation method. Background Technology

[0002] Carbon black is an amorphous carbon material produced by the incomplete combustion or thermal decomposition of hydrocarbons. Its primary particles are typically spherical particles of 10-500 nm, existing in chain or cluster aggregates. Due to its excellent reinforcing, conductive, and coloring properties, carbon black is widely used in rubber, inks, coatings, and other fields. However, in high-end applications such as lithium-sulfur battery carriers, supercapacitor electrodes, and high-efficiency adsorbents, higher requirements are placed on the pore structure of carbon black, especially requiring high pore volume (typically >2.0 cm³). 3 / g) and high structural uniformity (such as narrow pore size distribution and low particle size dispersion).

[0003] To improve the porosity of carbon black, existing technologies mainly employ post-treatment methods such as physical or chemical activation. For example, carbon black is physically activated using carbon dioxide or steam at high temperatures, or chemically activated using reagents such as potassium hydroxide or phosphoric acid. However, these activation processes typically involve non-selective etching of the original carbon black aggregates. While this can increase pore volume and specific surface area to some extent, it often results in problems such as excessive particle ablation, aggregate structure destruction, and widening of particle size distribution. Furthermore, chemical activation may introduce metallic or non-metallic impurities that are difficult to completely remove into the product, affecting the purity of the material and its stability in electrochemical applications.

[0004] The physical structure of carbon black determines the difficulty of controlling its pore size. Carbon black particles consist of three levels: primary particles, aggregates, and agglomerates. Primary particles are the basic structural units, while aggregates are stable structures formed by primary particles bonded together by chemical bonds. During activation, due to the inhomogeneity of the surface and internal structure of carbon black particles, oxidants tend to preferentially attack structurally weak areas, leading to preferential etching of the connection points between primary particles. This ultimately causes the aggregates to disintegrate and the particles to break down. This non-selective etching not only reduces the mechanical strength of carbon black but also leads to a wider pore size distribution and a decrease in the proportion of micropores, making it difficult to meet the requirements of precise pore structure control in high-end applications.

[0005] To achieve precise control over pore structure, the template method has been introduced into the preparation of porous carbon materials. This method involves depositing a carbon source on the surface of a hard template (such as silica or calcium carbonate) or a soft template (such as a surfactant), and then removing the template to replicate its structure. However, applying the template method to carbon black systems still faces challenges: on the one hand, the removal of traditional inorganic hard templates usually requires strong acid or strong alkali treatment, which can easily damage the carbon framework; on the other hand, how to effectively combine the template strategy with the unique aggregate formation mechanism of carbon black to obtain carbon black products with both high pore volume and high uniformity remains a technical problem that has not yet been fully solved in this field.

[0006] The unique challenges of template methods in carbon black preparation stem primarily from the unique mechanism of carbon black formation. Carbon black is formed through gas-phase pyrolysis, where primary particles nucleate, grow, and rapidly aggregate into chain-like structures in a high-temperature gas phase. This process typically occurs within milliseconds, with intense and difficult-to-control reaction conditions. Therefore, ensuring the uniform dispersion of template molecules and their participation in carbon black particle formation within such a short timeframe is the primary challenge for applying template methods to carbon black systems. Furthermore, the aggregate structure of carbon black possesses high thermodynamic stability, making it difficult to alter its basic structure through subsequent processing once formed. This implies that the template must function from the initial stage of carbon black particle formation to effectively guide the formation of pore structures. Existing research indicates that conventional template molecules struggle to maintain structural integrity and spatial positioning during carbon black formation, resulting in irregular pore structures and low micropore volume ratios in the final product.

[0007] In existing technologies, some studies have attempted to apply template methods to carbon black preparation. For example, some studies have used mesoporous silica as a template to prepare porous carbon black, but this method requires the removal of the template using hydrofluoric acid, which is a complex process and may damage the carbon skeleton. Other studies have tried using polymer microspheres as soft templates, but due to the mismatch between the polymer microspheres and the carbon black formation process, the pore structure of the final product is not uniform.

[0008] Fullerene (C 60 As a zero-dimensional carbon nanomaterial with a highly symmetrical spherical structure and good monodispersity, fullerenes possess the theoretical potential to serve as molecular-level templates due to their regular molecular size, which could be used to induce the formation of uniformly sized micropores. However, currently available technologies rarely report on the direct application of fullerenes to the regulation of carbon black pore structure. In particular, there is a lack of methods that can effectively utilize the structural characteristics of fullerenes to guide the formation of regular channels during carbon black synthesis, and then selectively remove the template through a mild and controllable post-processing technique, thereby obtaining high-purity, ultra-high pore volume, and highly uniform carbon black while maintaining the integrity of the carbon framework. Therefore, developing such a process has become an important research direction to meet the needs of high-end applications. Summary of the Invention

[0009] The purpose of this invention is to provide a highly uniform ultra-high pore volume carbon black and its preparation method. The highly uniform ultra-high pore volume carbon black is prepared by using fullerene as a molecular template and through a gradient oxidation post-treatment process, thereby solving the problems of low pore volume, wide pore size distribution and poor particle uniformity in the prior art.

[0010] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0011] This invention provides a method for preparing highly uniform ultra-high pore volume carbon black, comprising the following steps:

[0012] (1) Fullerene C 60 Dispersed in an aromatic precursor, the mixture is mechanically stirred and ultrasonically treated to form a homogeneous mixture, and the temperature is maintained at 25 to 35°C.

[0013] (2) The homogeneous mixture is placed in a tube furnace and subjected to pyrolysis and carbonization under an inert atmosphere to obtain C. 60 @Carbon black core-shell structure;

[0014] (3) The C 60 @The carbon black core-shell structure is placed in an oxidizing atmosphere for the first stage of low-temperature oxidation treatment;

[0015] (4) Place the product obtained in step (3) in a carbon dioxide atmosphere for a second stage of high-temperature oxidation treatment;

[0016] (5) The product obtained in step (4) is placed in a mixed atmosphere of hydrogen and inert gas for reduction treatment to obtain carbon black product.

[0017] Further, in step (1), the fullerene C 60 The mass ratio of the aromatic precursor to the precursor is 1:20 to 1:50; wherein the aromatic precursor is one of toluene, xylene, naphthalene, and anthracene.

[0018] Further, in step (1), the mechanical stirring rate is 300 to 500 revolutions per minute; the ultrasonic treatment power is 400 to 600 watts, and the treatment time is 20 to 40 minutes.

[0019] Further, in step (2), the temperature of the pyrolysis carbonization is 700 to 850°C, the heating rate is 5 to 10°C / min, and the time is 10 to 60 minutes; the inert atmosphere is nitrogen or argon, and the flow rate is 100 to 300 mL / min.

[0020] Further, in step (3), the temperature of the first low-temperature oxidation treatment is 280 to 320°C, the heating rate is 2 to 5°C / min, and the time is 0.5 to 2 hours; the oxidation atmosphere is air or oxygen.

[0021] Furthermore, in step (3), the first stage of low-temperature oxidation treatment adopts a segmented heating strategy, first holding at 250°C for 10 minutes, and then heating up to the temperature of the first stage of low-temperature oxidation treatment.

[0022] Further, in step (4), the temperature of the second high-temperature oxidation treatment is 530 to 570°C, the heating rate is 3 to 5°C / min, and the time is 1 to 3 hours; the carbon dioxide flow rate is 50 to 200 mL / min.

[0023] Furthermore, in step (4), after the second high-temperature oxidation treatment, the product after the second high-temperature oxidation treatment is further cooled to room temperature in a carbon dioxide atmosphere at a rate of 3 to 5 °C / min.

[0024] Further, in step (5), the reduction treatment temperature is 350 to 450°C and the time is 0.5 to 2 hours; the volume ratio of hydrogen to inert gas is 1:3 to 1:5.

[0025] The present invention also provides a carbon black prepared by the aforementioned method, wherein the carbon black has a pore volume ≥ 2.8 cm³. 3 / g, specific surface area ≥1500m² 2 / g, micropore volume ratio ≥86.5%, particle size distribution range ≤0.87.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] (1) Achieved synergistic improvement in pore volume and uniformity: This invention utilizes fullerene (C 60 Using [a specific material] as a molecular-level template, a high-density, uniformly sized microporous structure was successfully induced. Test data shows that the total pore volume of the obtained carbon black can reach 2.86-3.48 cm³. 3 / g, with a microporous volume ratio as high as 86.5%-92.1%.

[0028] (2) Significantly improved particle structural uniformity: The present invention adopts a two-stage gradient oxidation process of "low-temperature oxidation + high-temperature oxidation", which effectively ensures the integrity of the carbon skeleton during template removal. Particle size analysis shows that the particle size distribution span of the product is as low as 0.82-0.87, proving that the process of the present invention plays a decisive role in particle uniformity.

[0029] (3) It endows the material with superior electrochemical performance: The carbon black prepared by this invention has high pore volume, high micropore volume ratio and high uniformity. The combined effect of these three factors makes it perform well in energy storage applications. As a lithium-sulfur battery carrier, the initial discharge specific capacity is ≥1180mAh / g; as a supercapacitor electrode, the specific capacitance is ≥298F / g, and the capacity retention rate is ≥94.8% after 10,000 cycles, which is significantly better than the comparative example. Detailed Implementation

[0030] To enable those skilled in the art to better understand the technical solutions of this invention, the present application will be further described in detail below with reference to embodiments.

[0031] Example 1

[0032] 1. Raw material mixing: Weigh 1.0g of fullerene (C 60 Add 20.0g of xylene (purity ≥99.5%) to the mixture (mass ratio 1:20). Place the mixture in a sealed glass reactor (pressure range ≥0.3MPa to cope with possible local high temperature and pressure fluctuations during ultrasonic treatment), turn on the magnetic stirrer (stirring speed 300rpm), and simultaneously start the probe-type ultrasonic instrument (power 400W, frequency 20kHz, probe immersed 2cm below the liquid surface) for 20 minutes to obtain a homogeneous and transparent mixture. Maintain the temperature at 25℃ by circulating water through the reactor jacket.

[0033] 2. Pyrolysis Carbonization: The above mixture is injected into a quartz boat and pushed into the isothermal zone of a tube furnace. High-purity argon gas (99.999% purity, flow rate 100 mL / min) is introduced to replace the air in the furnace three times. The temperature is increased to 700℃ at a rate of 5℃ / min and held at this temperature for 10 minutes. After the reaction is complete, the mixture is naturally cooled to below 100℃ in an argon atmosphere. The black powder is then removed, which is carbon (C). 60 @Carbon black core-shell structure.

[0034] 3. First stage of low-temperature oxidation: Place the core-shell structure powder in a muffle furnace and purge with dry air (dew point < -40℃). Use staged heating: first hold at 250℃ for 10 minutes, then increase to 280℃ at a rate of 2℃ / min and hold for 0.5 hours. After completion, purge with nitrogen for 10 minutes and cool to room temperature.

[0035] 4. Second-stage high-temperature oxidation: The low-temperature oxidation product is loaded into a quartz boat and placed in a tube furnace. High-purity CO2 (purity ≥99.99%, flow rate 50 mL / min) is introduced three times for purging. The temperature is raised to 530°C at a rate of 3°C / min and held for 1 hour (the single run time should not exceed 4 hours to avoid softening and deformation of the quartz tube due to prolonged exposure to high temperatures). After the reaction is complete, the temperature is cooled to room temperature in a CO2 atmosphere at a rate of 3°C / min.

[0036] 5. Hydrogen Reduction: The high-temperature oxidation product was placed in a tube furnace and purged with high-purity nitrogen for 5 minutes to ensure an oxygen content of <0.1%. Then, an H2 / Ar mixture (hydrogen to argon volume ratio 1:3, dehydrated by 5A molecular sieve, water content <1ppm) was introduced at a flow rate of 200 mL / min. A staged heating strategy was adopted: only Ar was introduced below 200℃, and H2 was gradually introduced after 200℃. The temperature was increased to 350℃ at a rate of 5℃ / min and held for 0.5 hours. After completion, the product was cooled to below 100℃ in an Ar atmosphere, removed, and vacuum dried at 120℃ for 12 hours to obtain carbon black.

[0037] Equipment Operation Details: During the pyrolysis and carbonization stage, the isothermal zone length of the tube furnace should be no less than 30 cm to ensure uniform heating of the sample. The loading of the quartz boat should be controlled to no more than 50 mg per square centimeter to avoid material accumulation leading to uneven heat transfer. During the oxidation stage, it is recommended to use a muffle furnace or tube furnace with atmosphere control to ensure uniform distribution of the oxidizing atmosphere. During the high-temperature oxidation stage, the CO2 flow rate should be stable and controllable; a mass flow controller with an accuracy of no less than ±1% is recommended. During ultrasonic treatment, overheating should be avoided to prevent solvent evaporation; a circulating cooling water system is recommended to maintain the reaction temperature.

[0038] Safety Precautions: The exhaust gas generated during the pyrolysis and carbonization stage contains incompletely decomposed aromatic compounds and should be treated by activated carbon adsorption and high-temperature incineration systems. During the hydrogen reduction stage, the hydrogen concentration should be strictly controlled within a safe range (<4%), and a hydrogen leak detection alarm device should be installed in the system. The experimental area should be equipped with an explosion-proof ventilation system with an air exchange frequency of no less than 12 times / hour.

[0039] Exhaust gas treatment: The exhaust gas generated during the pyrolysis, carbonization and oxidation stages is treated by activated carbon adsorption and incineration systems to ensure that harmful substances such as benzene are completely decomposed.

[0040] Example 2

[0041] 1. Raw material mixing: Weigh 1.0g of fullerene (C 60 Add 1 part (purity ≥99.5%) to 30.0 g of toluene (mass ratio 1:30). Place the mixture in a sealed glass reactor (pressure range ≥0.3 MPa to cope with possible local high temperature and pressure fluctuations during ultrasonic treatment), turn on the magnetic stirrer (stirring speed 400 rpm), and simultaneously start the probe-type ultrasonic instrument (power 500W, frequency 20kHz, probe immersed 2 cm below the liquid surface) for 30 minutes to obtain a homogeneous and transparent mixture. Circulate water through the reactor jacket to maintain the temperature at 30℃.

[0042] 2. Pyrolysis Carbonization: The above mixture is injected into a quartz boat and pushed into the isothermal zone of a tube furnace. High-purity argon gas (99.999% purity, flow rate 200 mL / min) is introduced to replace the air in the furnace three times. The temperature is programmed to rise to 800℃ at a rate of 8℃ / min and held at that temperature for 30 minutes. After the reaction is complete, the mixture is naturally cooled to below 100℃ in an argon atmosphere. The black powder is then removed, which is carbon (C). 60 @Carbon black core-shell structure.

[0043] 3. First stage of low-temperature oxidation: Place the core-shell structure powder in a muffle furnace and purge with dry air (dew point < -40℃). Use staged heating: first hold at 250℃ for 10 minutes, then increase to 300℃ at a rate of 3℃ / min and hold for 1 hour. After completion, purge with nitrogen for 10 minutes and cool to room temperature.

[0044] 4. Second-stage high-temperature oxidation: The low-temperature oxidation product is loaded into a quartz boat and placed in a tube furnace. High-purity CO2 (purity ≥99.99%, flow rate 150 mL / min) is introduced three times for purging. The temperature is raised to 550°C at a rate of 4°C / min and held for 2 hours (each run should not exceed 4 hours to avoid softening and deformation of the quartz tube due to prolonged exposure to high temperatures). After the reaction is complete, the mixture is cooled to room temperature in a CO2 atmosphere at a rate of 4°C / min.

[0045] 5. Hydrogen Reduction: The high-temperature oxidation product was placed in a tube furnace and purged with high-purity nitrogen for 5 minutes to ensure an oxygen content of <0.1%. Then, an H2 / Ar mixture (hydrogen to argon volume ratio 1:4, dehydrated by 5A molecular sieve, water content <1ppm) was introduced at a flow rate of 200 mL / min. A staged heating strategy was adopted: only Ar was introduced below 200℃, and H2 was gradually introduced after 200℃. The temperature was increased to 400℃ at a rate of 5℃ / min and held for 1 hour. After completion, the product was cooled to below 100℃ in an Ar atmosphere, removed, and vacuum dried at 120℃ for 12 hours to obtain carbon black.

[0046] Exhaust gas treatment: Same as in Example 1.

[0047] Example 3

[0048] 1. Raw material mixing: Weigh 1.0g of fullerene (C 60 Add 50.0g of anthracene (purity ≥99.5%) to a mass ratio of 1:50. Place the mixture in a sealed glass reactor (pressure range ≥0.3MPa to cope with possible local high temperature and pressure fluctuations during ultrasonic treatment), turn on the magnetic stirrer (stirring speed 500rpm), and simultaneously start the probe-type ultrasonic instrument (power 600W, frequency 20kHz, probe immersed 2cm below the liquid surface) for 40 minutes to obtain a homogeneous and transparent mixture. Maintain the temperature at 35℃ by circulating water through the reactor jacket.

[0049] 2. Pyrolysis Carbonization: The above mixture is injected into a quartz boat and pushed into the isothermal zone of a tube furnace. High-purity nitrogen (99.999% purity, flow rate 300 mL / min) is introduced to replace the air in the furnace three times. The temperature is programmed to rise to 850℃ at a rate of 10℃ / min and held at that temperature for 60 minutes. After the reaction is complete, the mixture is naturally cooled to below 100℃ in a nitrogen atmosphere. The black powder is then removed, which is carbon (C). 60 @Carbon black core-shell structure.

[0050] 3. First stage of low-temperature oxidation: Place the core-shell structure powder in a muffle furnace and introduce dry oxygen (dew point < -40℃). Use staged heating: first hold at 250℃ for 10 minutes, then increase to 320℃ at a rate of 5℃ / min and hold for 2 hours. After completion, purge with nitrogen for 10 minutes and cool to room temperature.

[0051] 4. Second-stage high-temperature oxidation: The low-temperature oxidation product is loaded into a quartz boat and placed in a tube furnace. High-purity CO2 (purity ≥99.99%, flow rate 200 mL / min) is introduced three times for purging. The temperature is raised to 570°C at a rate of 5°C / min and held for 3 hours (each run should not exceed 4 hours to avoid softening and deformation of the quartz tube due to prolonged exposure to high temperatures). After the reaction is complete, the mixture is cooled to room temperature in a CO2 atmosphere at a rate of 5°C / min.

[0052] 5. Hydrogen Reduction: The high-temperature oxidation product was placed in a tube furnace and purged with high-purity nitrogen for 5 minutes to ensure an oxygen content of <0.1%. Then, an H2 / Ar mixture (hydrogen to argon volume ratio 1:5, dehydrated by 5A molecular sieve, water content <1ppm) was introduced at a flow rate of 200 mL / min. A staged heating strategy was adopted: only Ar was introduced below 200℃, and H2 was gradually introduced after 200℃. The temperature was increased to 450℃ at a rate of 5℃ / min and held for 2 hours. After completion, the product was cooled to below 100℃ in an Ar atmosphere, removed, and vacuum dried at 120℃ for 12 hours to obtain carbon black.

[0053] Exhaust gas treatment: Same as in Example 1.

[0054] Comparative Example 1

[0055] Except for step 1, where fullerene was not added and only 30.0g of toluene was used, the steps and parameters in this comparative example were exactly the same as in Example 2.

[0056] Comparative Example 2

[0057] 1. Raw material mixing: The operation is the same as step 1 in Example 2.

[0058] 2. Pyrolysis and carbonization: The operation is the same as step 2 in Example 2.

[0059] 3. Oxidation treatment: The obtained C60 The carbon black core-shell structure powder was placed in a tube furnace and purged three times with high-purity CO2 (purity ≥99.99%, flow rate 150 mL / min). The temperature was increased to 550°C at a rate of 4°C / min and held for 2 hours. After the reaction, the powder was cooled to room temperature at a rate of 4°C / min in a CO2 atmosphere. Only the first low-temperature oxidation step in Example 2 was omitted.

[0060] 4. Hydrogen reduction: The operation is the same as step 5 in Example 2.

[0061] Data Analysis and Comparison

[0062] To objectively evaluate the technical effects of the present invention, quantitative tests were conducted on the carbon black samples prepared in Examples 1-3 and Comparative Examples 1-2, focusing on five core indicators: pore volume, specific surface area, micropore volume ratio, uniformity of primary particle size distribution, and electrochemical performance. The details are as follows:

[0063] (1) Pore volume and specific surface area: A fully automated gas adsorption instrument was used to determine the high-precision nitrogen adsorption-desorption isotherm at 77 K. Before the test, the sample was degassed under vacuum at 200°C for 12 hours. Based on the nonlocal density functional theory (NLDFT) model (carbon slit pore model) recommended by the International Union of Pure and Applied Chemistry (IUPAC), the total pore volume (cm³) was directly calculated from the adsorption isotherm. 3 / g), total specific surface area (m²) 2 / g) and micropore volume (cm) 3 ( / g), and the micropore diameter is <2 nm.

[0064] (2) Micropore volume ratio: Based on the calculation results of the above NLDFT model, the micropore volume ratio = (micropore volume / total pore volume) × 100%.

[0065] (3) Particle size distribution uniformity: A laser particle size analyzer was used to perform wet dispersion tests on the samples using deionized water as the dispersion medium. The D10, D50, and D90 values ​​(unit: nm) of the particle size distribution were recorded, and the particle size distribution span (Span) was calculated. Span = (D90 - D10) / D50, where D10 represents the particle size at a cumulative volume fraction of 10%, D50 represents the particle size at a cumulative volume fraction of 50%, and D90 represents the particle size at a cumulative volume fraction of 90%. The smaller the Span value, the more concentrated and uniform the particle size distribution.

[0066] (4) Lithium-sulfur battery performance: Carbon black and sulfur were mixed at a mass ratio of 3:7, and a composite cathode material was prepared by melt diffusion method. Using this material as the working electrode and lithium sheet as the counter electrode, CR2032 coin cells were assembled. Constant current charge-discharge test was performed at 0.2C rate (1C=1675mA / g), and the first discharge specific capacity (mAh / g) was recorded.

[0067] (5) Supercapacitor performance: Carbon black, conductive carbon black, and polyvinylidene fluoride (PVDF) were mixed at a mass ratio of 8:1:1 and coated onto a nickel foam current collector to prepare an electrode sheet. A three-electrode system was assembled using 6 mol / L KOH solution as the electrolyte. Constant current charge-discharge tests were performed at a current density of 1 A / g, and the specific capacitance (F / g) was calculated. A 10,000-cycle test was conducted, and the capacity retention rate (%) was recorded.

[0068] The test results are summarized in Table 1.

[0069]

[0070] The test data on the ratio of total pore volume to micropore volume in Table 1 show that the total pore volume of Examples 1-3 is ≥2.86 cm³. 3 / g, the micropore volume ratio is ≥86.5%, which is better than Comparative Example 1 (1.15cm). 3 / g, 65.3%) and Comparative Example 2 (2.17cm) 3 / g, 78.6%). Example 2, as the preferred embodiment, has a total pore volume as high as 3.48 cm³. 3 / g, with a micropore volume ratio of 92.1%. Comparative Example 1, lacking a fullerene template, lacked molecular-level structural guidance during carbon black formation, leading to random particle aggregation and insufficient pore structure development, thus failing to construct high-density micropores. Therefore, both the pore volume and micropore volume ratio were low. Comparative Example 2, although introducing a fullerene template and achieving a certain pore volume, lacked a first-stage low-temperature oxidation process. During direct high-temperature oxidation, the oxidant struggled to penetrate uniformly into the particles, resulting in incomplete template removal. Simultaneously, the carbon skeleton underwent non-uniform etching during the high-temperature oxidation stage, causing damage to some microporous structures. Therefore, the micropore volume ratio was lower than in the examples.

[0071] The Span value test data in Table 1 show that the Span values ​​of Examples 1-3 are all ≤0.87, exhibiting excellent particle size distribution uniformity. Among them, the Span value of Example 2 is as low as 0.82. In contrast, the Span value of Comparative Example 1 is 1.42. This is because the lack of fullerene template constraint caused the carbon black particles to randomly collide and aggregate during formation, resulting in a large particle size distribution range and irregular aggregate morphology. The Span value of Comparative Example 2 is as high as 1.58, even higher than that of Comparative Example 1. This is mainly attributed to the lack of the first stage of low-temperature oxidation pretreatment. Direct high-temperature oxidation caused non-uniform etching of the carbon skeleton—weaker structural areas were over-oxidized while stronger structural areas were under-oxidized. This non-uniform oxidation process further increased the structural differences between particles. The data shows that the fullerene template, by acting as a nucleation center, guides the uniform growth of carbon black particles, which helps to achieve pore structure regularity. The two-stage gradient oxidation process, through the pre-formation of a microporous network by the first stage of low-temperature oxidation, provides a uniform channel for the second stage of high-temperature oxidation, which helps to maintain the overall uniformity of the particles.

[0072] The electrochemical performance test data in Table 1 show that Examples 1-3 exhibit excellent performance in both lithium-sulfur battery and supercapacitor applications. Their initial discharge specific capacity is ≥1180 mAh / g, specific capacitance is ≥298 F / g, and capacity retention after 10,000 cycles is ≥94.8%. Comparative Examples 1 and 2, however, show relatively lower performance, which is directly related to their structural defects. Comparative Example 1, due to its low micropore volume ratio and poor particle uniformity, cannot effectively restrict polysulfide migration, resulting in an initial discharge specific capacity of only 820 mAh / g for the lithium-sulfur battery and a specific capacitance of only 185 F / g for the supercapacitor. While Comparative Example 2 outperforms Comparative Example 1, its performance is still significantly lower than the examples. This is mainly due to incomplete template removal leading to a reduction in effective pore volume, and the pore structure defects caused by non-uniform etching resulting in uneven electrolyte wetting and reduced ion transport efficiency, affecting the uniformity and stability of the electrochemical reaction and leading to decreased cycle performance.

[0073] In summary, this invention utilizes fullerenes as molecular templates and combines a gradient oxidation post-treatment process, including a first-stage low-temperature oxidation and a second-stage high-temperature carbon dioxide oxidation, to prepare a carbon black material. The carbon black prepared by this method exhibits high pore volume, a high micropore volume ratio, and a narrow particle size distribution. Furthermore, it demonstrates superior electrochemical performance in lithium-sulfur battery and supercapacitor tests, successfully solving the problems of low pore volume, wide pore size distribution, and poor particle uniformity inherent in traditional carbon black.

Claims

1. A method for preparing highly uniform ultra-high pore volume carbon black, characterized in that, Includes the following steps: (1) Fullerene C 60 Dispersed in an aromatic precursor, the mixture is mechanically stirred and ultrasonically treated to form a homogeneous mixture, and the temperature is maintained at 25 to 35°C. (2) The homogeneous mixture is placed in a tube furnace and subjected to pyrolysis and carbonization under an inert atmosphere to obtain C. 60 @Carbon black core-shell structure; (3) The C 60 The carbon black core-shell structure is placed in an oxidizing atmosphere for the first stage of low-temperature oxidation treatment; wherein, the temperature of the first stage of low-temperature oxidation treatment is 280 to 320°C. (4) The product obtained in step (3) is placed in a carbon dioxide atmosphere and subjected to a second high-temperature oxidation treatment; wherein the temperature of the second high-temperature oxidation treatment is 530 to 570°C. (5) The product obtained in step (4) is placed in a mixed atmosphere of hydrogen and inert gas for reduction treatment to obtain carbon black product.

2. The preparation method according to claim 1, characterized in that, In step (1), the fullerene C 60 The mass ratio of the aromatic precursor to the precursor is 1:20 to 1:50; wherein the aromatic precursor is one of toluene, xylene, naphthalene, and anthracene.

3. The preparation method according to claim 1, characterized in that, In step (1), the mechanical stirring rate is 300 to 500 revolutions per minute; the ultrasonic treatment power is 400 to 600 watts, and the treatment time is 20 to 40 minutes.

4. The preparation method according to claim 1, characterized in that, In step (2), the temperature of the pyrolysis carbonization is 700 to 850°C, the heating rate is 5 to 10°C / min, and the time is 10 to 60 minutes; the inert atmosphere is nitrogen or argon, and the flow rate is 100 to 300 mL / min.

5. The preparation method according to claim 1, characterized in that, In step (3), the heating rate of the first low-temperature oxidation treatment is 2 to 5 °C / min, and the time is 0.5 to 2 hours; the oxidation atmosphere is air or oxygen.

6. The preparation method according to claim 5, characterized in that, In step (3), the first stage of low-temperature oxidation treatment adopts a segmented heating strategy, first holding at 250℃ for 10 minutes, and then heating up to the temperature of the first stage of low-temperature oxidation treatment.

7. The preparation method according to claim 1, characterized in that, In step (4), the heating rate of the second high-temperature oxidation treatment is 3 to 5 °C / min, and the time is 1 to 3 hours; the carbon dioxide flow rate is 50 to 200 mL / min.

8. The preparation method according to claim 7, characterized in that, In step (4), after the second high-temperature oxidation treatment, the product after the second high-temperature oxidation treatment is further cooled to room temperature in a carbon dioxide atmosphere at a rate of 3 to 5 °C / min.

9. The preparation method according to claim 1, characterized in that, In step (5), the reduction treatment is carried out at a temperature of 350 to 450°C for 0.5 to 2 hours; the volume ratio of hydrogen to inert gas is 1:3 to 1:

5.

10. A carbon black prepared by the method according to any one of claims 1 to 9, characterized in that, The carbon black has a pore volume ≥ 2.86 cm³. 3 / g, specific surface area ≥1500m² 2 / g, micropore volume ratio ≥86.5%, particle size distribution range ≤0.87.

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