Preparation method of superconducting carbon black and application thereof

Abstract

This invention relates to the field of carbon black preparation technology, and discloses a method for preparing superconducting carbon black and its application. The preparation method includes the following steps: (1) dissolving carbon black raw material in water, adding an activator for activation to obtain a carbon black solution; heating the reaction vessel to 850-1400℃, introducing an active gas to react with the carbon black solution to obtain an intermediate product; (2) collecting the intermediate product and heating it at high temperature to obtain nanoporous superconducting carbon black. The nanoporous superconducting carbon black obtained by processing ordinary carbon black raw material in this invention significantly improves the specific surface area of ​​ordinary carbon black raw material, and at the same time, further improves the structure, conductivity and added value of carbon black raw material.

Description

Technical Field

[0001] This invention relates to the technical field of carbon black preparation, and in particular to a method for preparing superconducting carbon black and its application. Background Technology

[0002] Currently, carbon black can be divided into rubber-grade carbon black and non-rubber-grade carbon black. Conductive carbon black, a type of non-rubber-grade carbon black, possesses the characteristics of "three highs and one excellent"—high specific surface area, high structure, high purity, and excellent conductivity. With the rapid development of the new energy industry, lithium batteries have become the primary application scenario for conductive carbon black. Lithium-ion batteries require conductive agents to have excellent conductivity, low density, and stable structure and chemical properties. Conductive carbon black not only meets the requirements that the conductive agent does not participate in redox reactions in the battery and has high resistance to acid and alkali corrosion, but also features low cost and light weight.

[0003] Well-known international conductive carbon blacks include Lion Corporation's Ketjenblack series of superconducting carbon blacks, Cabot Corporation's VXC series of conductive carbon blacks, and Evonik Degussa's PRINTEX XE2-B and HIBLAXK 40B2. Domestically, due to limited demand for conductive carbon blacks and foreign technological monopolies, my country's technological development in conductive carbon black has been slow, resulting in a reliance on imports. This is particularly true for conductive carbon blacks used in lithium batteries, which are considered mid-to-high-end, where foreign technological monopolies are even more pronounced. Imported conductive carbon blacks are significantly more expensive than domestically produced ones. Currently, mainstream conductive carbon blacks for lithium batteries have relatively low specific surface areas. While low specific surface areas offer excellent dispersibility, their conductivity is difficult to further improve, and their addition amounts are generally 3-4 times higher than high-end conductive carbon blacks. The application of low-end conductive carbon blacks in mining pipes, cable shielding, and other rubber and plastic products is currently limited, preventing their widespread use in lithium battery manufacturing.

[0004] Therefore, how to provide a nanoporous superconducting carbon black with a high specific surface area is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] In view of this, the present invention provides a method for preparing superconducting carbon black, which yields a high-end superconducting carbon black product with high specific surface area and porosity. This addresses the problems of poor conductivity, low added value, limited application fields, and inability to meet the needs of the new energy lithium battery market for domestically produced conductive carbon black, making it more advantageous than ordinary conductive carbon black for lithium batteries in lithium battery applications.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0007] A method for preparing superconducting carbon black includes the following steps:

[0008] (1) After dissolving the carbon black raw material in water, an activator is added to activate it, and a carbon black solution is obtained;

[0009] The reaction vessel is heated to 850-1400℃, and an active gas is introduced to react with the carbon black solution to obtain an intermediate product.

[0010] (2) The intermediate product is collected and heated at high temperature to obtain nanoporous superconducting carbon black.

[0011] Preferably, the activator is one or more selected from KOH, K2CO3, NaOH, Na2CO3, Na2O, Ca(OH)2, KHCO3, NaHCO3, KCl, NaCl, KF, NaF, and MgCl2.

[0012] Preferably, the active gas includes any one or more of the following: hydrogen, oxygen, methane, carbon monoxide, carbon dioxide, and saturated water vapor.

[0013] Preferably, the preparation process of the carbon black solution in step (1) is as follows:

[0014] Carbon black raw material and solvent water are dissolved in a mass ratio of 1:10-100. After adding dispersant, emulsification is carried out. After emulsification, activator is added and stirred.

[0015] The emulsification time is 5-30 min, the amount of activator added is less than or equal to the solid content of the carbon black raw material, the stirring rate is 1-15 r / min, and the stirring time is 5-30 min.

[0016] Preferably, the flow rate of the active gas is 0-200 kg / h; the flow rate of the carbon black solution is 100-500 kg / h.

[0017] Preferably, in step (1), the heating process is carried out in an inert environment, and the inert gas flow rate is 5-50 m³ / h. 3 / h, inert gas purity >99.99%.

[0018] Preferably, the high-temperature heating in step (2) is a staged heating: the reaction temperature of the first stage is 550-800℃, and the constant temperature holding time is 10-240min; the reaction temperature of the second stage is 1400-2500℃, and the constant temperature holding time is 10-240min.

[0019] Preferably, step (2) is carried out in an inert environment. After the reaction is completed, inert gas is continuously passed through until the nanoporous superconducting carbon black is removed. The inert gas flow rate is 5-50 m³ / h.3 / h, inert gas purity >99.99%.

[0020] Preferably, in the above method for preparing nanoporous superconducting carbon black, the inert gas in the high-temperature reactor includes the following gas path:

[0021] The first gas path is horizontally introduced into the gas outlet position at the top of the high-temperature reactor.

[0022] And / or a second gas path, which is horizontally introduced into the carbon black material outlet position at the bottom of the high-temperature reactor;

[0023] And / or a third gas path, which enters the bottom of the high-temperature reactor at an angle downwards, and the third gas path is located at the top of the second gas path.

[0024] Preferably, in the above method for preparing nanoporous superconducting carbon black, the high-temperature reactor includes an outer furnace shell, a heat insulation layer, and a high-temperature resistant layer; the heat insulation layer is arranged around the inner side of the outer furnace shell for heat insulation; the high-temperature resistant layer is arranged around the inner side of the heat insulation layer for providing a reaction site for the carbon black powder and the active gas.

[0025] More preferably, the high-temperature resistant layer is made of silicon carbide composite material.

[0026] Preferably, in the above method for preparing nanoporous superconducting carbon black, the active gas is introduced into the high-temperature reactor through a gas nozzle, and the gas nozzle is installed on the side wall of the high-temperature reactor.

[0027] The pretreated carbon black / the posttreated conductive carbon black is introduced into the high-temperature reactor through a material nozzle, which is installed on the side wall of the high-temperature reactor and is symmetrically arranged with the gas nozzle.

[0028] More preferably, both the gas nozzle and the material nozzle are connected to a meter and / or a flow meter.

[0029] Preferably, in the above method for preparing nanoporous superconducting carbon black, both the material nozzle and the gas nozzle include a high-temperature section and a low-temperature section; the high-temperature section is located at one end near the center of the high-temperature reactor; the low-temperature section is detachably connected to the high-temperature section, and the low-temperature section is located at one end away from the center of the high-temperature reactor.

[0030] The present invention also provides a nanoporous superconducting carbon black prepared by any of the above methods.

[0031] The present invention also provides an application of nanoporous superconducting carbon black prepared by any of the above methods in the field of batteries.

[0032] This invention discloses a method for preparing superconducting carbon black, which has the following advantages compared with the prior art:

[0033] The specific surface area of ​​ordinary carbon black masterbatch is significantly increased from a low level to an ultra-high level, and the structure and electrical conductivity of carbon black raw materials are greatly improved, further enhancing the added value of carbon black.

[0034] The chemical activation process is characterized by easy adjustment of the product's pore structure, but its disadvantages include high corrosiveness to equipment and environmental pollution. The physical activation process is characterized by low environmental pollution and simple operation, but its disadvantages include difficulty in precise control of product porosity and unevenness. This invention adopts a scheme combining chemical and physical activation, which combines the advantages of both methods while solving the shortcomings of the original methods. It can produce higher quality products with higher specific surface area and uniform porosity, while ensuring that the production process causes less pollution to the environment or equipment.

[0035] In step (1), high-temperature physical activation and partial chemical activation occur at a certain temperature. In step (2), chemical activation reaction occurs again at a low temperature, followed by high-temperature carbonization and purification at a higher temperature. In addition, the reaction temperature is higher than the boiling point of the activator, so that it is vaporized and discharged in time.

[0036] The process employs a combination of high-temperature activation and high-temperature carbonization. First, high-temperature activation: amorphous carbon exists on short carbon layers rich in defects. These carbon layers exhibit an unusual density of active sites and high oxidation reactivity. During the reaction of the carbon black with an active gas at high temperature, they are preferentially removed, relatively increasing the carbon atom content that makes up the microcrystals, thereby enhancing the conductivity of the original carbon black. Following high-temperature activation, high-temperature carbonization is then performed: on the one hand, this causes a certain degree of rearrangement of the graphite-like domains (BSUs) within the carbon black's internal microstructure, increasing the average diameter La of the graphite-like domains and forming larger graphite-like domain sheets, which is more conducive to its conductivity. On the other hand, by setting different carbonization temperatures, residual chemical reagents and other surface functional groups in the material are removed through high-temperature purification, thus ensuring the high purity requirements of the product.

[0037] The nanoporous conductive carbon black product of this invention requires less carbon black addition than other conductive carbon blacks, thus allowing for the filling of more active material and improving battery capacity. Compared with ordinary conductive carbon black in lithium battery applications, the high specific surface area and porous superconducting carbon black can significantly reduce charge transfer resistance. The battery resistance does not increase due to volume changes during charging and discharging, improving battery stability. One of its advantages is its application in high-rate and high-current-density lithium batteries. Attached Figure Description

[0038] Figure 1This is the adsorption-desorption isotherm curve of the carbon black raw material of this invention;

[0039] Figure 2 This is the adsorption-desorption isotherm curve of nanoporous superconducting carbon black of the present invention;

[0040] Figure 3 This is the NLDFT curve of the carbon black raw material of this invention;

[0041] Figure 4 This is the NLDFT curve of the nanoporous superconducting carbon black of this invention;

[0042] Figure 5 This is the first charge-discharge curve of the sample battery of Example 1 of the present invention and carbon black raw material at 0.1C;

[0043] Figure 6 This is a rate characteristic diagram of the battery for two carbon black samples of the present invention;

[0044] Figure 7 This is a surface impedance diagram of the battery electrode of two carbon black samples of the present invention;

[0045] Figure 8 This is a schematic diagram of the high-temperature reactor in an embodiment of the present invention.

[0046] In the diagram: 1-outer furnace shell, 2-insulation layer, 3-high temperature resistant layer, 4-gas nozzle, 5-material nozzle. Detailed Implementation

[0047] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0048] As described in the background section, the mainstream conductive carbon black products currently on the market for lithium batteries have a low specific surface area, making it difficult to improve conductivity. Compared to high-end conductive carbon black, their addition amount is generally 3-4 times that of high-end conductive carbon black, and they cannot be widely used in lithium battery manufacturing.

[0049] This invention provides a method for preparing superconducting carbon black, resulting in a high-end superconducting carbon black product with high specific surface area and porosity. This addresses the problems of poor conductivity, low added value, limited application areas, and inability to meet the demands of the new energy lithium battery market for domestically produced conductive carbon black, making it more advantageous in lithium battery applications compared to ordinary conductive carbon black for lithium batteries.

[0050] This invention provides a method for preparing superconducting carbon black, comprising the following steps:

[0051] (1) Dissolve carbon black raw material and solvent water in a mass ratio of 1:10-100, add activator to activate, and obtain carbon black solution;

[0052] The high-temperature reactor is heated to 850-1400℃, and active gas is introduced to react with the carbon black solution to obtain an intermediate product.

[0053] (2) Collect the intermediate products and heat them at high temperature to obtain nanoporous superconducting carbon black.

[0054] In the above steps, the mass ratio of carbon black raw material to water in step (1) can be 1:10, 1:20, 1:40, 1:60, 1:80, 1:100, etc.; the temperature of the above reaction vessel can be raised to 850℃, 900℃, 100℃, 1200℃, 1400℃.

[0055] It should be noted that the nanoporous superconducting carbon black prepared by the above method involves reacting the carbon black raw material with an active gas at high temperature to form an intermediate product, followed by high-temperature heating treatment. This process helps to form a nanoporous carbon black material, increasing its specific surface area and pore volume, thereby increasing the material's active surface area and usable space.

[0056] This product exhibits characteristics of zero resistance and complete magnetic field repulsion, along with excellent electrical conductivity and magnetism. This superconducting property is of great significance for applications such as batteries, as it can improve battery performance and efficiency.

[0057] The properties and structure of carbon black raw materials can be improved and controlled through the addition and reaction of activators. The selection of activators and the optimization of treatment conditions can give carbon black materials higher activity and special surface chemical properties, thereby enhancing their adsorption capacity, catalytic performance, and other characteristics, which helps to expand their applications in energy storage, catalytic reactions, and other fields.

[0058] Furthermore, the activator is one or more of the following: KOH, K2CO3, NaOH, Na2CO3, Na2O, Ca(OH)2, KHCO3, NaHCO3, KCl, NaCl, KF, NaF, and MgCl2;

[0059] The active gas includes any one or more of the following: hydrogen, oxygen, methane, carbon monoxide, carbon dioxide, and saturated water vapor; the flow rate of the active gas is 0-200 kg / h; the flow rate of the carbon black solution is 100-500 kg / h.

[0060] It should be noted that the role of the activating gas is not only to participate in the reaction, but also to remove impurities and gases. During the reaction, the activating gas helps to remove impurities and gases from the carbon black solution. Through the introduction and reaction of the activating gas, volatile impurities and gases in the carbon black solution can be rapidly carried away and removed at high temperatures, ensuring the purity and stability of the reaction process.

[0061] Furthermore, the preparation process of the carbon black solution in step (1) is as follows:

[0062] The carbon black raw material is dissolved in water, a dispersant is added and then emulsified. After emulsification, an activator is added and the mixture is stirred.

[0063] The emulsification time is 5-30 min, the amount of activator added is less than or equal to the solid content of the carbon black raw material, the stirring rate is 1-15 r / min, and the stirring time is 5-30 min.

[0064] It should be noted that the above operations have at least the following effects: dispersion and emulsification. Adding a dispersant and then emulsifying helps to uniformly disperse the carbon black raw material in water, forming a homogeneous carbon black solution. This improves the dispersibility of carbon black in water, prevents aggregation and agglomeration, and ensures better subsequent reactions. The addition of an activator, after emulsification, followed by stirring, can initiate a series of chemical reactions and surface modification processes. The activator alters the surface chemical properties of the carbon black, increases the number of active sites, and induces adjustments to the microstructure and the formation of surface functional groups, thereby increasing the activity and special chemical reactivity of the carbon black. The stirring process helps to mix the reactants, ensuring that the activator is uniformly distributed in the carbon black solution, promoting the reaction and uniform activation modification. Furthermore, it should be noted that the activator includes, but is not limited to, the reagents listed above.

[0065] Furthermore, in step (1), the heating process is carried out in an inert environment, with an inert gas flow rate of 5-50 m³ / h. 3 / h, inert gas purity >99.99%.

[0066] Furthermore, in step (2), the high-temperature heating is carried out in stages: the reaction temperature of the first stage is 550-800℃, and the constant temperature holding time is 10-240min; the reaction temperature of the second stage is 1400-2500℃, and the constant temperature holding time is 10-240min.

[0067] Furthermore, step (2) is carried out in an inert environment. After the reaction is completed, inert gas is continuously passed through until the nanoporous superconducting carbon black is removed. The inert gas flow rate is 5-50 m³ / h. 3 / h, inert gas purity >99.99%.

[0068] The apparatus used in the following embodiments includes: emulsifier, mixing tank, high-pressure transfer pump, high-temperature reactor, graphite sagger, and high-temperature graphite furnace;

[0069] Among them, high-temperature reactors, such as Figure 8 As shown, it includes an outer furnace shell 1, an insulation layer 2, and a high-temperature resistant layer 3. The insulation layer 2 is arranged around the inner side of the outer furnace shell 1 for heat insulation. It should be noted that the fiber insulation layer 2 can use commercially available fiber insulation materials without special restrictions. The high-temperature resistant layer 3 is arranged around the inner side of the insulation layer 2 to provide a reaction site for carbon black powder and active gas. Preferably, the high-temperature resistant layer 3 is made of silicon carbide composite material and is fixedly connected to the insulation layer 2 by ceramic fasteners that are resistant to high-temperature oxidation.

[0070] Furthermore, the active gas is introduced into the high-temperature reactor through the gas nozzle 4, which is installed on the side wall of the high-temperature reactor; the carbon black liquid is introduced into the high-temperature reactor through the material nozzle 5, which is installed on the side wall of the high-temperature reactor and is symmetrically arranged with the gas nozzle 4; and both the gas nozzle 4 and the material nozzle 5 are connected to a meter and / or a flow meter.

[0071] Understandably, the carbon black liquid and the active gas are introduced into the high-temperature reactor through different nozzles, and the flow rate can be controlled separately by flow meters, metering devices, etc. Therefore, by adjusting the flow parameters of the carbon black liquid and the active gas respectively, the carbon black liquid can be subjected to different degrees of oxidation reaction, thereby obtaining nanoporous superconducting carbon black products of different specifications.

[0072] Furthermore, both the material nozzle 5 and the gas nozzle 4 include a high-temperature section and a low-temperature section; the high-temperature section is located at the end near the center of the high-temperature reactor, and the high-temperature section is made of silicon carbide / silicon nitride composite material, which is resistant to high-temperature oxidation and corrosion and ensures the high purity requirements of the material; the low-temperature section is detachably connected to the high-temperature section, and the low-temperature section is located at the end away from the center of the high-temperature reactor, and the low-temperature section can be made of 316L stainless steel.

[0073] Furthermore, the injection angles of the active gas and carbon black liquid into the high-temperature reactor are both ±90° of the horizontal baseline, preferably ±20°. That is, the injection angles of both the material nozzle 5 and the gas nozzle 4 can be adjusted, which can increase the diversity of the collision reaction between the material and the active gas, increase the residence time of the carbon black liquid in the reaction chamber, and ensure a more complete reaction.

[0074] Furthermore, the inert gas within the high-temperature reactor includes at least one of the following moving gas paths:

[0075] The first gas path is horizontally directed into the gas outlet at the top of the high-temperature reactor, and inert gas is introduced into the top of the high-temperature reactor; the second gas path is horizontally directed into the carbon black material outlet at the bottom of the high-temperature reactor, and inert gas is introduced into the bottom of the high-temperature reactor; the third gas path is obliquely directed into the bottom of the high-temperature reactor, and the third gas path is located above the second gas path.

[0076] The first and second gas paths can cool the gaseous / carbon black material products and protect the pretreated / posttreated conductive carbon black from participating in additional oxidation reactions under high temperature conditions. The third gas path can not only cool the pretreated / posttreated conductive carbon black, but also promote the settling of carbon black materials and improve reaction efficiency.

[0077] It should also be noted that multiple gas paths can be set up, whether it is the first, second, or third gas path. It is preferable to set them symmetrically, that is, the inert gas moves relative to each other in the high-temperature reactor, which can accelerate the cooling or material settling effect.

[0078] The test standards corresponding to the various performance indicators in the following examples are as follows: Specific surface area (BET) test standard is based on GB / T10722-2014; External specific surface area (STSA) test standard is based on GB / T10722-2014; Iodine uptake value test standard is based on GB / T3780.1-2015; Structure density (DBP) test standard is based on GB / T 3780.2-2017; Metallic Fe content test standard is based on ByICP-OES; Ash content (825℃) test standard is based on GB / T3780.10-2017; Powder conductivity test standard is based on GB / T3782-2006; Powder resistivity test standard is based on GB / T 3782-2006.

[0079] Example 1

[0080] S1: Prepare a carbon black solution by mixing carbon black raw material Super p Li (manufacturer: Timcal) with water solvent at a ratio of 1:20. The dispersant is ethanol, which accounts for 0.3% of the carbon black raw material fraction. The emulsification time in the emulsifier is 10 min to obtain a stable and dispersed carbon black solution with a solid content of 5%, which is then introduced into a stirring tank.

[0081] S2: Add the KOH chemically activated reactant to the above 5% concentration carbon black solution. The ratio of KOH added to the dry weight of carbon black raw material is 1:20. Stir in a mixing tank at a stirring rate of 5 r / min for 15 min to achieve a thorough dispersion and obtain a carbon black mixed solution.

[0082] S3: Subsequent experiments were conducted using the high-temperature reactor described above. The reactor was heated to the reaction temperature under an inert atmosphere, and then the active gas was introduced into the high-temperature reaction chamber through a nozzle at a controlled gas flow rate. Nitrogen was selected as the inert gas, the reaction temperature was 1000℃, the nitrogen purity was ≥99.99%, and the flow rate was 20 m³ / s. 3 / h, the active gas is saturated water vapor, and the steam flow rate is controlled at 25kg / h;

[0083] S4: The 5% carbon black mixed solution is injected through a nozzle via a high-pressure delivery pump at a flow rate controlled at 80 kg / h. An active gas is injected from the opposite side. On the one hand, the carbon black mixed solution undergoes a chemical activation reaction at high temperature, and on the other hand, it undergoes a collision oxidation reaction with the active gas on the opposite side under high temperature conditions. The nozzle injection angle is 0°.

[0084] S5: The intermediate product obtained from the material collection is loaded into a graphite sagger and sent to an intermittent high-temperature graphite furnace. Under the protection of nitrogen atmosphere, the temperature is first raised to 700℃ and held at that temperature for 60 minutes, and then raised to 1750℃ and held at that temperature for 60 minutes to perform high-temperature carbonization and purification of the material; nitrogen purity ≥99.99%, flow rate 15m3 / h.

[0085] S6: After the intermittent high-temperature graphite furnace is kept at a constant temperature, nitrogen continues to circulate. After cooling to room temperature, the material is removed, and high specific surface area nanoporous superconducting carbon black is obtained.

[0086] Example 2

[0087] The only difference between this embodiment and Embodiment 1 is that the reaction temperature in S3 is 850°C.

[0088] Example 3

[0089] The difference between this embodiment and Embodiment 1 is that the reaction temperature in S3 is 1400℃.

[0090] Comparative Example 1

[0091] The difference between this comparative example and Example 1 is that the reaction temperature in S3 is 800°C.

[0092] Comparative Example 2

[0093] The difference between this comparative example and Example 1 is that the reaction temperature in S3 is 1600°C.

[0094] The present invention conducted performance tests on the basic physicochemical properties of the nanoporous superconducting carbon black prepared in Examples 1-3 and Comparative Example 1. The results are shown in Table 1.

[0095] Table 1

[0096]

[0097] As shown in Table 1, by using the method of the present invention, the carbon black raw material can be significantly increased from a low specific surface area to an ultra-high specific surface area after high-temperature activation and carbonization treatment. At the same time, the iodine uptake value, structural value and powder conductivity of the sample are significantly improved, and the purity of the sample (metallic Fe content and ash content) can also be guaranteed. Meanwhile, compared with Examples 1-3, the performance of some basic physicochemical indicators of the products prepared by Comparative Examples 1 and 2 is worse.

[0098] Example 4

[0099] The difference between this embodiment and embodiment 1 is that in S5, under the protection of nitrogen atmosphere, the temperature is first raised to 550°C and kept at a constant temperature for 60 minutes, and then raised to 1400°C and kept at a constant temperature for 60 minutes.

[0100] Example 5

[0101] The difference between this embodiment and embodiment 1 is that in S5, under the protection of nitrogen atmosphere, the temperature is first raised to 800°C and kept at a constant temperature for 60 minutes, and then raised to 2500°C and kept at a constant temperature for 60 minutes.

[0102] Comparative Example 3

[0103] The difference between this embodiment and embodiment 1 is that in S5, under the protection of nitrogen atmosphere, the temperature is first raised to 500°C and kept at a constant temperature for 60 minutes, and then raised to 1200°C and kept at a constant temperature for 60 minutes.

[0104] Comparative Example 4

[0105] The difference between this embodiment and embodiment 1 is that in S5, under the protection of nitrogen atmosphere, the temperature is first raised to 900°C and kept at that temperature for 60 minutes, and then raised to 2500°C and kept at that temperature for 60 minutes.

[0106] This table presents the performance tests of the basic physicochemical properties of the nanoporous superconducting carbon black prepared in Examples 4 and 5 and Comparative Examples 3 and 4. The results are shown in Table 2.

[0107] Table 2

[0108]

[0109] As shown in Table 2, the temperature setting is particularly important when maintaining constant temperature in the high-temperature reactor. Too low or too high a temperature will affect the performance of the nanoporous superconducting carbon black prepared by high-temperature composite activation modification.

[0110] Comparative Example 5

[0111] The difference between this comparative example and Example 1 is that S5-7 are omitted, that is, the intermediate product obtained by steps S1-S4 is the conductive carbon black product.

[0112] Comparative Example 6

[0113] S1: The carbon black raw material Super p Li is directly loaded into a graphite sagger and sent to an intermittent high-temperature graphite furnace. Under the protection of nitrogen atmosphere, the temperature is first raised to 700℃ and held at that temperature for 60 minutes, and then raised to 1750℃ and held at that temperature for 60 minutes to perform high-temperature carbonization and purification treatment on the material; the nitrogen purity is ≥99.99% and the flow rate is 15m3 / h.

[0114] S2: After the intermittent high-temperature graphite furnace is kept at a constant temperature, nitrogen continues to circulate and the material is cooled to room temperature. The material is then removed to obtain nanoporous superconducting carbon black with a high specific surface area.

[0115] The present invention conducted performance tests on the nanoporous superconducting carbon black prepared in Comparative Examples 5 and 6, and the results are shown in Table 3.

[0116] Table 3

[0117]

[0118] As shown in Table 3, the present invention adopts a combination of chemical activation and physical activation. Compared with the simple physical activation and partial chemical activation or only chemical activation of Comparative Examples 5 and 6, the present invention can prepare superconducting carbon black with higher specific surface area, more uniform porosity and better conductivity.

[0119] Example 6

[0120] This comparative example is basically the same as Example 1, except that the activation gas is replaced with hydrogen in S3.

[0121] Example 7

[0122] This comparative example is basically the same as Example 1, except that the activation gas is replaced with methane in S3.

[0123] Example 8

[0124] This comparative example is basically the same as Example 1, except that in S3 the activation gas is replaced with a mixture of carbon monoxide and water vapor, and the volume ratio of carbon monoxide to water vapor is 1:1.

[0125] Comparative Example 7

[0126] This comparative example is basically the same as Example 1, except that: it does not involve the subsequent processing of the carbon black solution prepared in S2 and S1.

[0127] Comparative Example 8

[0128] This comparative example is basically the same as Example 1, except that the carbon black mixed solution prepared in S3 and S2 was not subjected to subsequent processing.

[0129] The performance of the nanoporous superconducting carbon black prepared in Comparative Examples 5 and 6 was tested, and the results are shown in Table 4.

[0130] Table 4

[0131]

[0132] As shown in Table 4, when the pretreated carbon black is in solution, the addition of chemically activated reactants has a significant impact on the conductivity of conductive carbon black products. The high-temperature carbonization process and the activation process after high-temperature carbonization also affect the presence of amorphous carbon in the carbon black raw material and the arrangement of the graphite-like microcrystalline structure. Therefore, they have a significant impact on the external surface area, specific surface area, structure, and conductivity of conductive carbon black products.

[0133] The porosity of the nanoporous superconducting carbon black prepared in Example 1 was analyzed and tested, and the results are shown in Table 5.

[0134] Table 5

[0135]

[0136] Depend on Figure 1-4 As shown in Table 5, the nanoporous superconducting carbon black prepared by the method of this invention exhibits an adsorption-desorption isotherm conforming to a type IV isotherm, proving the presence of micropores, mesopores, and macropores. Under the same relative pressure P / P0 conditions, compared with the carbon black raw material Super p Li, the product in Example 1 has a higher adsorption capacity, indicating a relatively larger total pore volume. The data in Table 5 demonstrate that after high-temperature activation treatment, the total pore volume of the carbon black sample significantly increased from the original 0.1396 to 1.0423. Furthermore, under the non-local density function theory method, the measured specific surface area of ​​the sample increased substantially from the original 55 to 691.

[0137] In addition, conductive carbon black, as a conductive agent, is a key auxiliary material for lithium batteries. It is coated on positive and negative electrode materials. A certain amount of conductive carbon black is added during the electrode manufacturing process to increase the conductivity of electrons and lithium ions. By forming a conductive network on the surface of the active material, it accelerates the electron transport rate. At the same time, it can absorb and retain the electrolyte, providing more electrolyte interfaces for lithium ions, thereby improving battery charging efficiency and extending battery life.

[0138] Specifically, the steps for preparing a battery using conductive carbon black as a conductive agent are as follows: Take lithium iron phosphate cathode, conductive carbon black, and PVDF in a mass ratio of 90:5:5, and prepare a uniform slurry using NMP (N-methylpyrrolidone) as the solvent. First, in a mixing tank, dissolve the binder PVDF in small batches in NMP solvent (1-2.5% solute mass fraction), stirring until a uniform transparent solution is obtained. Then, grind lithium iron phosphate and conductive carbon black into powder, slowly add them to the prepared uniform transparent solution, and vacuum planetary stir for 8-10 hours to obtain a uniform black slurry. Place the slurry on aluminum foil, and use a scraper to evenly coat it into a sheet, ensuring uniform adhesion to the aluminum foil surface. Place the prepared cathode material coating in an oven, first drying at 80℃ for 4 hours, then vacuum drying at 120℃ for 12 hours. Then, cut the cathode electrode sheet, assemble a simulated battery in a glove box, store at room temperature for 12 hours, and then conduct battery testing.

[0139] Batteries were prepared using Super p Li carbon black raw material and the high specific surface area, nanoporous superconducting carbon black prepared in Example 1 as conductive agent raw materials. The first charge-discharge specific capacity, rate performance and electrochemical impedance spectroscopy of each battery were tested.

[0140] Figure 5 The first charge-discharge curves of batteries prepared from two carbon black samples at 0.1C are shown. The first-time efficiency of the sample battery made from carbon black raw material Super p Li is 92.78% and the specific capacity is 146.32 mAh / g. The first-time efficiency of the sample battery of the product of Example 1 obtained after high-temperature composite activation is 93.35% and the specific capacity is 150.49 mAh / g.

[0141] During the charging process of a button cell battery, a charging plateau occurs, corresponding to a voltage. Similarly, during the discharging process, a discharging plateau occurs, also corresponding to a voltage. The difference between the charging plateau voltage and the discharging plateau voltage reflects the degree of polarization of the battery. Generally speaking, the more ideal the battery, the lower its polarization resistance (Rp), meaning the better the battery performance. Figure 5 As can be seen from the data, compared with the carbon black raw material Super p Li, the nanoporous superconducting carbon black after high-temperature activation treatment has a smaller voltage difference between charge and discharge. This indicates that the smaller the RP of the nanoporous superconducting carbon black battery, the better the battery.

[0142] First, the circuit was subjected to three constant current charge-discharge cycles at 0.1C, followed by tests at different rates of 0.5C, 1C, 2C, and 3C. Figure 6As shown, at low-rate discharge, the output specific capacity of the batteries from the two carbon black samples is not significantly different. However, as the rate gradually increases, the difference in output specific capacity between the two carbon black samples becomes more pronounced. The superconducting carbon black sample obtained after high-temperature composite activation treatment exhibits better rate characteristics in the battery. This is mainly due to the sample's high specific surface area and high porosity structure, which allows it to store more electrolyte, making it more favorable for Li during high-rate discharge. + Transport within the electrodes, thereby reducing electrode polarization.

[0143] Under the same battery sample preparation conditions, i.e., a mass ratio of lithium iron phosphate cathode, conductive carbon black, and PVDF of 90:5:5, the conductivity of different conductive carbon blacks in the battery system can be reflected to some extent by measuring the surface impedance values ​​of the battery electrodes. Figure 7 As can be seen, carbon black raw material is a conductive agent, and the surface impedance value of the prepared battery electrode is 813Ω, while the surface impedance value of the battery electrode prepared in Example 1 is reduced to 227Ω. This indicates that the nanoporous superconducting carbon black obtained after high-temperature composite activation treatment has a better conductivity in the battery system.

[0144] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. The solutions disclosed in the embodiments are described simply because they correspond to the methods disclosed in the embodiments; relevant parts can be found in the method section.

[0145] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing superconducting carbon black, characterized in that, Includes the following steps: (1) After dissolving the carbon black raw material in water, an activator is added to activate it, and a carbon black solution is obtained; The reaction vessel is heated to 850-1400℃, and an active gas is introduced to react with the carbon black solution to obtain an intermediate product. (2) The intermediate product is collected and heated at high temperature to obtain nanoporous superconducting carbon black; The activator is one or more selected from KOH, K2CO3, NaOH, Na2CO3, Na2O, Ca(OH)2, KHCO3, NaHCO3, KCl, NaCl, KF, NaF, and MgCl2; The active gas includes any one or more of the following: hydrogen, oxygen, methane, carbon monoxide, carbon dioxide, and saturated water vapor. The preparation process of the carbon black solution in step (1) is as follows: Carbon black raw material and solvent water are dissolved in a mass ratio of 1:10-100. After adding dispersant, emulsification is carried out. After emulsification, activator is added and stirred. The emulsification time is 5-30 min, the amount of activator added is less than or equal to the solid content of the carbon black raw material, the stirring rate is 1-15 r / min, and the stirring time is 5-30 min. In step (1), the heating process is carried out in an inert environment, with an inert gas flow rate of 5-50 m³ / h. 3 / h, inert gas purity >99.99%; The high-temperature heating in step (2) is a staged heating: the reaction temperature of the first stage is 550-800℃, and the constant temperature holding time is 10-240min; the reaction temperature of the second stage is 1400-2500℃, and the constant temperature holding time is 10-240min. Step (2) is carried out in an inert environment. After the reaction is complete, the inert gas continues to flow until the nanoporous superconducting carbon black is removed. The inert gas flow rate is 5-50 m³ / h. 3 / h, inert gas purity >99.99%.

2. The method for preparing superconducting carbon black according to claim 1, characterized in that, The flow rate of the active gas is 0-200 kg / h; the flow rate of the carbon black solution is 100-500 kg / h.

3. A superconducting carbon black prepared by the method according to any one of claims 1-2.

4. The application of superconducting carbon black prepared by the method according to any one of claims 1-2 in the field of batteries.

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