High-crystallinity, high-structure and high-specific-surface-area conductive carbon black, preparation method therefor, device, electrode slurry and secondary battery

Abstract

The present disclosure relates to the technical field of carbon black materials, and in particular to high-crystallinity, high-structure and high-specific-surface-area conductive carbon black, a preparation method therefor, a device, an electrode slurry, and a secondary battery. The high-crystallinity, high-structure and high-specific-surface-area conductive carbon black has a crystallinity of 42-51%, a BET specific surface area of 58-200 m2 / g, and a cOAN of 108-180 mL / 100 g. The conductive carbon black of the present disclosure simultaneously achieves high crystallinity, high structure, and high specific surface area. When the conductive carbon black is used as a conductive agent, on the one hand, the high crystallinity endows the conductive agent with excellent conductivity and stability and improved compatibility with an electrolyte solution; on the other hand, the structure has sufficient length, perfect network structure, and liquid absorption and retention capacity, so that the conductive carbon black has good conductivity, ion conduction capability, and dispersity and can significantly improve the performance of batteries.

Description

High-crystallinity, high-structure, high-specific-surface-area conductive carbon black, its preparation method, equipment, electrode slurry, and secondary batteries.

[0001] Cross-reference to related applications

[0002] This disclosure claims priority to Chinese Patent Application No. 202410483521.0, filed on April 22, 2024, entitled "High-structure, high-specific-surface-area conductive carbon black based on high crystallinity and its preparation method, equipment and electrode slurry, and secondary battery", the entire contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure relates to the field of carbon black materials technology, and in particular to a high-structure, high-specific-surface-area conductive carbon black based on high crystallinity, its preparation method, equipment, electrode slurry, and secondary battery. Background Technology

[0004] Carbon black, as a high-quality conductive / thermal conductive additive, is widely used in rubber and plastics, dry batteries, lead-acid batteries, microwave absorbing materials, and secondary lithium batteries. Although the proportion of carbon black added as an additive is not high, it plays a crucial role in applications such as electrical conductivity, thermal conductivity, and functional solvent adsorption (electrolyte adsorption performance). Especially in lithium-ion batteries, it can improve the conductivity of active materials and promote the wetting of active materials by the electrolyte, thereby improving battery performance.

[0005] During carbon black production, primary particles melt to form larger three-dimensional aggregates with branched structures, known as the primary structure of carbon black. These aggregates, with their well-developed branched and porous structures, further agglomerate into agglomerates through physical forces such as van der Waals forces. Compared to novel conductive agents like carbon nanotubes and graphene, the aggregates of carbon black particles possess well-developed branched and porous structures, which helps improve battery performance.

[0006] Although some furnace blacks possess high surface area and structure, the use of heavy oil as a raw material during their production results in residual impurities such as sulfur, phosphorus, and moisture, affecting the long-term stability of batteries. Furthermore, the furnace black production reaction is endothermic, requiring the addition of natural gas for aerobic combustion to maintain the necessary heat. This results in a high concentration of oxygen-containing functional groups, a relatively low reaction temperature (1400–2000℃), and low crystallinity. Additionally, the need to add water to terminate the reaction leads to partial oxidation and residual moisture, further impacting long-term stability.

[0007] The existing thermal pyrolysis process for preparing acetylene black requires the introduction of modifying gases such as oxygen and water vapor to improve the specific surface area and structure of the product. However, this method leads to the formation of oxygen-containing functional groups on the product surface, reducing the product's purity and affecting battery life when used in batteries. Furthermore, the introduction of oxygen and water vapor lowers the reaction temperature, reducing the product's crystallinity and limiting its intrinsic electronic conductivity—a fundamental characteristic.

[0008] Therefore, it is of great significance to prepare conductive carbon black with high crystallinity, high structure, and high specific surface area without introducing oxygen-containing substances.

[0009] In view of this, this disclosure is hereby made. Summary of the Invention

[0010] The purpose of this disclosure is to provide a highly crystalline, high-structure, high-specific-surface-area conductive carbon black, its preparation method, equipment, electrode slurry, and secondary battery. The carbon black obtained by this disclosure has high crystallinity, high structure, and high specific surface area without introducing oxygen-containing substances, and possesses good conductivity and ion conduction ability.

[0011] To achieve the aforementioned objectives of this disclosure, one aspect of this disclosure is to provide a highly conductive carbon black with high crystallinity, characterized by a high structure and high specific surface area, wherein the conductive carbon black has a crystallinity of 42%–51% and a BET specific surface area of ​​58–200 m². 2 / g, COAN is 108~180mL / 100g.

[0012] In a specific embodiment of this disclosure, the OAN of the conductive carbon black is 240-350 mL / 100 g.

[0013] In a specific embodiment of this disclosure, the structural change rate X of the conductive carbon black is 48.6% to 55%; wherein, the structural change rate X = (OAN - cOAN) / OAN.

[0014] In a specific embodiment of this disclosure, the crystallinity of the conductive carbon black is 45% to 51%.

[0015] In a specific embodiment of this disclosure, the crystallite size Lc of the conductive carbon black is

[0016] In specific embodiments of this disclosure, the average lattice spacing d(002) of the conductive carbon black is ≤0.3546nm, such as 0.3503~0.3546nm.

[0017] In a specific embodiment of this disclosure, the average particle size of the primary particles of the conductive carbon black is 26–45 nm.

[0018] In a specific embodiment of this disclosure, the average pore size of the conductive carbon black is 9.63–10.56 nm.

[0019] In a specific embodiment of this disclosure, the conductive carbon black, with pores ranging from 2 to 50 nm in size, was measured to have a volume of 0.1089 to 0.2851 cm³ by nitrogen desorption. 3 / g.

[0020] In a specific embodiment of this disclosure, the volume of pores with a size of 2 to 50 nm in the conductive carbon black accounts for more than 86.87% of the total pore volume, such as 86.87% to 90.6%.

[0021] This disclosure also provides a method for preparing any of the above-described conductive carbon black, comprising the following steps:

[0022] In an environment containing plasma and isolated from air, gaseous hydrocarbons undergo thermal decomposition under the action of a microwave plasma generator to form carbon black.

[0023] In a specific embodiment of this disclosure, during the thermal pyrolysis reaction, the temperature of the plasma reaction zone is controlled to be 3000–3500°C.

[0024] In a specific embodiment of this disclosure, the gaseous hydrocarbon flow direction is arranged at an angle to the flow direction of the medium gas that generates the plasma. Further, the angle is 30° to 45°.

[0025] In specific embodiments of this disclosure, the gaseous hydrocarbon includes at least one selected from acetylene, toluene, benzene, ethylene, propylene, and butadiene. Further, the gaseous hydrocarbon is acetylene.

[0026] In specific embodiments of this disclosure, the medium gas for generating the plasma includes at least one of hydrogen, nitrogen, and argon.

[0027] In a specific embodiment of this disclosure, the flow rate ratio of the gaseous hydrocarbon to the medium gas that generates the plasma is (4 to 13.5):1.

[0028] In a specific embodiment of this disclosure, the reaction further includes: introducing a cooling gas at the end of the reaction zone to cool the carbon black formed by the thermal decomposition reaction, thereby terminating the reaction. Further, the cooling gas includes at least one of hydrogen, nitrogen, and argon.

[0029] This disclosure also provides an apparatus for implementing any of the above-described methods for preparing carbon black, comprising: a pyrolysis furnace body having a reaction chamber formed therein; and a microwave plasma generator;

[0030] The pyrolysis furnace body forms a furnace head and a cooling section, with the outlet of the furnace head connected to the inlet of the cooling section; the furnace head is provided with two nozzles communicating with the reaction chamber and at least one first gas inlet pipe communicating with the reaction chamber;

[0031] The microwave plasma generator is configured correspondingly to the first gas inlet pipe to generate plasma within the reaction chamber.

[0032] In a specific embodiment of this disclosure, at least one second gas inlet pipe is also included, which is in communication with the reaction chamber; the second gas inlet pipe is located at the furnace head and near the outlet of the furnace head.

[0033] In a specific embodiment of this disclosure, two first gas inlet pipes are included, which are arranged opposite to each other on both sides of the furnace head. Further, the central axis of each first gas inlet pipe is arranged at an angle to the central axis of the furnace head. The included angle is 45° to 60°.

[0034] In a specific embodiment of this disclosure, two second gas inlet pipes are provided, which are arranged opposite to each other on both sides of the furnace head.

[0035] In a specific embodiment of this disclosure, two microwave plasma generators are included, which are arranged opposite to each other on both sides of the furnace head.

[0036] This disclosure also provides an electrode paste comprising any of the conductive carbon blacks described above.

[0037] This disclosure also provides a secondary battery, including a positive electrode, a negative electrode, an electrolyte, and a separator; at least one of the positive electrode and the negative electrode is made from any of the electrode slurries described above.

[0038] Compared with the prior art, the beneficial effects of this disclosure are as follows:

[0039] (1) The conductive carbon black disclosed herein has high crystallinity, high structure and high specific surface area. When used as a conductive agent, on the one hand, the high crystallinity gives it excellent conductivity and stability and improves compatibility with electrolyte. On the other hand, the structure has sufficient length, perfect network structure and liquid absorption and retention capacity, and has good conductivity, ion conduction capacity and dispersibility, which can significantly improve battery performance.

[0040] (2) The method for preparing conductive carbon black disclosed herein is simple to operate and suitable for large-scale production. Attached Figure Description

[0041] To more clearly illustrate the technical solutions in the specific embodiments of this disclosure or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0042] Figure 1 is a schematic diagram of the apparatus for preparing conductive carbon black provided in an embodiment of this disclosure;

[0043] Figure 2 is a top view of the nozzle and furnace head provided in an embodiment of this disclosure;

[0044] Figure 3 shows the Raman spectrum of the carbon black prepared in Example 1 of this disclosure;

[0045] Figure 4 shows the Raman spectrum of the carbon black prepared in Example 2 of this disclosure;

[0046] Figure 5 shows the Raman spectrum of the carbon black prepared in Example 3 of this disclosure;

[0047] Figure 6 shows the Raman spectrum of the carbon black prepared in Example 4 of this disclosure;

[0048] Figure 7 shows the Raman spectrum of carbon black in Comparative Example 1;

[0049] Figure 8 shows the XRD patterns of carbon black in Examples 1-4 and Comparative Example 1 of this disclosure;

[0050] Figure 9 shows the rate performance test results of batteries obtained using carbon black from Examples 1-4 and Comparative Example 1 as conductive agents.

[0051] Reference numerals: 10-Pyrolysis furnace body; 20-Microwave plasma generator; 11-Reaction chamber; 12-Furnace head; 13-Nozzle; 14-First gas inlet pipe; 15-Second gas inlet pipe; 16-Cooling section; 17-Discharge port; 131-First nozzle; 132-Second nozzle. Detailed Implementation

[0052] The technical solutions of this disclosure will be clearly and completely described below with reference to the accompanying drawings and specific embodiments. However, those skilled in the art will understand that the embodiments described below are only some embodiments of this disclosure, not all embodiments, and are only used to illustrate this disclosure, and should not be regarded as limiting the scope of this disclosure. Based on the embodiments in this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0053] In the description of this disclosure, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this disclosure 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 disclosure. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0054] In the description of this disclosure, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linkage" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this disclosure based on the specific circumstances.

[0055] Carbon black, as a high-quality conductive / thermal conductive additive, is widely used in rubber and plastics, dry batteries, lead-acid batteries, microwave absorbing materials, and secondary lithium batteries. However, existing carbon blacks typically require modification by introducing oxygen-containing substances to improve their specific surface area and structure. The introduction of oxygen-containing substances has two main drawbacks: firstly, it generates oxygen-containing functional groups on the product surface, leading to side reactions such as decomposition and gas production in the electrochemical system, thus affecting battery life; secondly, it lowers the reaction temperature, reducing the crystallinity of the product and limiting the intrinsic electronic conductivity of the carbon black. This means that existing conductive carbon blacks cannot simultaneously achieve high crystallinity, high structure, and high specific surface area, directly hindering their further widespread application.

[0056] Based on this, this disclosure provides a high-structure, high-specific-surface-area conductive carbon black with high crystallinity, having a crystallinity of 42%–51% and a BET specific surface area of ​​58–200 m².2 / g, COAN is 108~180mL / 100g.

[0057] The conductive carbon black disclosed herein possesses high crystallinity, high structure, and high specific surface area. When used as a conductive agent, its high crystallinity endows it with excellent conductivity and stability, as well as improved compatibility with electrolytes. Furthermore, its structure has sufficient length, a perfect network structure, and liquid absorption and retention capabilities, resulting in good conductivity, ion conduction, and dispersibility, which can significantly improve battery performance.

[0058] The crystallinity of carbon black can characterize its graphitization degree. Crystallinity is measured in Raman spectroscopy as the ratio of the peak area of ​​the G band to the sum of the peak areas of the G and D bands (S0). G / S G+D The conductive carbon black disclosed herein has a crystallinity of 42% to 51%, such as 45% to 51%. Compared to existing carbon blacks, the crystallinity is significantly improved, indicating that the conductive carbon black of this disclosure has a high degree of graphitization. Therefore, when the conductive carbon black of this disclosure is used as a conductive agent, its high degree of graphitization can improve the conductivity of the electrode active material or enhance the stability of the material to ensure battery performance. In the conductive carbon black of this disclosure, the crystallinity of the carbon black can be within the range of 42%, 44%, 45%, 46%, 49%, 51%, or any combination thereof.

[0059] The specific Raman spectroscopy testing methods and parameters disclosed herein are as follows:

[0060] Using a laser Raman spectroscopy device, several test particles were placed on a glass slide and scraped repeatedly with a scraper to make it flat. The test was conducted under the following conditions: YAG laser (excitation wavelength): 514nm, number of lines: 600gr / mm, filter: D0.6, objective lens magnification: 100x, exposure time: 150 seconds, cumulative number of times: 2.

[0061] The BET specific surface area was tested according to the method in GB / T 19587-2004. The BET specific surface area of ​​carbon black can reflect the development of its pore structure. The conductive carbon black disclosed in this paper has a BET specific surface area of ​​58–200 μm². 2 The BET specific surface area within the above range indicates that the conductive carbon black of this disclosure has a well-developed porosity and branched structure, increasing the number of contact points with other substances (such as active materials in electrodes), thus fully utilizing the conductivity of the carbon black; simultaneously, it possesses high conductivity-imparting ability due to its percolation effect in electrode materials. In the conductive carbon black of this disclosure, the BET specific surface area can be 58 m² / g. 2 / g、61m 2 / g、77m 2 / g、85m2 / g, 100m 2 / g、120m 2 / g, 140m 2 / g、145m 2 / g、160m 2 / g、200m 2 / g or a range consisting of any two of them.

[0062] cOAN, or compressed oil absorption number, characterizes the structure of carbon black materials under compressed conditions and measures the secondary structure of carbon black (under operating conditions). It is determined using the standard method in GB / T 3780.4-2017 Carbon Black Part 4: Determination of Oil Absorption Value of Compressed Samples. The retention of carbon black structure under compressed conditions indicates its stability against shearing, grinding, impact, or rolling. The more porous the carbon black particles, the higher their structural density, resulting in better liquid absorption and retention capabilities. Higher-structure carbon black has a stronger ability to form a conductive network in lithium-ion battery electrodes through the bridging of its well-developed branched structures, allowing for the achievement of the percolation threshold with a smaller addition amount. High-structure carbon black conductive agents possess excellent liquid absorption and retention capabilities, increasing ion conduction pathways and improving lithium-ion migration rates, thereby enhancing battery performance. In electrodes, the carbon black concentration required to overcome the percolation threshold in the active material matrix typically depends on cOAN, meaning it decreases as cOAN increases. The conductive carbon black of this disclosure has a co-anodine (cOAN) of 108–180 mL / 100 g. This design ensures that the carbon black, when used as a conductive agent, possesses sufficient length, a well-developed network structure, and good liquid absorption and retention capabilities, resulting in excellent conductivity and ionic conductivity. Furthermore, a cOAN not exceeding 180 mL / 100 g suppresses the aggregation of aggregates into larger agglomerates due to entanglement, thus ensuring good dispersibility. In the conductive carbon black of this disclosure, the cOAN can be within the range of 108 mL / 100 g, 120 mL / 100 g, 130 mL / 100 g, 132 mL / 100 g, 140 mL / 100 g, 150 mL / 100 g, 160 mL / 100 g, 168 mL / 100 g, 170 mL / 100 g, 180 mL / 100 g, or any combination thereof.

[0063] In a specific embodiment of this disclosure, the OAN of the conductive carbon black is 240–350 mL / 100 g.

[0064] During the formation of carbon black, at high temperatures, spherical primary particles arrange themselves into chemically bonded branched or chain-like aggregates, forming the primary structure of carbon black. The primary structure is a permanent structure formed by strong chemical bonds between the aggregates. These aggregates then re-aggregate through electrostatic forces into larger clusters, forming the secondary structure of carbon black. The void volume generated by these aggregated carbon black particles is a measure of the carbon black structure and can be characterized by the oil absorption number (OAN). The OAN is determined using the standard method specified in GB / T3780.2-2017 Carbon Black Part 2: Determination of Oil Absorption Number. In the conductive carbon black disclosed herein, the OAN of the carbon black can be a range of 240 mL / 100 g, 245 mL / 100 g, 250 mL / 100 g, 260 mL / 100 g, 270 mL / 100 g, 280 mL / 100 g, 290 mL / 100 g, 300 mL / 100 g, 310 mL / 100 g, 320 mL / 100 g, 330 mL / 100 g, 338 mL / 100 g, 350 mL / 100 g, or any combination thereof.

[0065] In a specific embodiment of this disclosure, the structural change rate X of the conductive carbon black is 48.6% to 55%; wherein, the structural change rate X = (OAN - cOAN) / OAN.

[0066] A higher structural change rate in carbon black results in a greater amount of aggregates being destroyed during sample compression, indicating structural instability and reduced liquid absorption and retention capacity. Conversely, a lower structural change rate indicates that the carbon black material retains most of its structural integrity after compression, maintaining good liquid absorption and retention capacity. Studies have found that the structural change rate of carbon black cannot be too small; if it is, the amount of aggregates or agglomerates destroyed during sample compression is smaller, reducing the dispersibility of the carbon black. The conductive carbon black disclosed in this invention has a structural change rate controlled between 48.6% and 55%, enabling it to balance liquid absorption and retention capacity, conductivity, and dispersibility. Consequently, when used as a conductive agent in electrodes, it can significantly improve battery performance. In the conductive carbon black of this invention, the structural change rate can be within the range of 48.6%, 49%, 50%, 50.3%, 50.8%, 51.1%, 52%, 53%, 54%, 55%, 55%, or any combination thereof.

[0067] In specific embodiments of this disclosure, the average particle size of the primary particles of conductive carbon black is 26–45 nm.

[0068] It should be noted that the primary particles of conductive carbon black are approximately spherical, and the average particle size of the primary particles is obtained by averaging the particle sizes measured using photographs taken with a transmission electron microscope or similar instrument. Furthermore, the particle size is the circumspherical equivalent diameter calculated from the area of ​​the primary particles. In different embodiments, the average particle size of the primary particles of conductive carbon black can be within the range of 26 nm, 28 nm, 30 nm, 32 nm, 35 nm, 39 nm, 40 nm, 42 nm, 45 nm, or any combination thereof.

[0069] In a specific embodiment of this disclosure, the crystallite size Lc of the conductive carbon black is

[0070] Crystallite size Lc is a factor representing the crystallinity of carbon materials with a crystalline structure. It can be calculated based on X-ray diffraction data analyzed by X-ray diffraction (XRD) using the Scherrer equation below.

[0071] Scherrer equation: Lc=0.89λ / (βCosθ)

[0072] Where 0.89 is the Scherrer constant, λ is the wavelength, θ is the angle at the peak of the d-spacing (002), and β is the maximum full width at the peak of the d-spacing (002).

[0073] The crystallite size Lc of the conductive carbon black disclosed herein is significantly increased compared to existing carbon blacks, indicating that the degree of graphitization of the conductive carbon black disclosed herein is higher than that of existing carbon blacks. In the conductive carbon black of this disclosure, the crystallite size Lc can be... Or a range consisting of any two of them.

[0074] In specific embodiments of this disclosure, the average lattice spacing d(002) of the conductive carbon black is ≤0.3546 nm, such as 0.3503~0.3546 nm.

[0075] The degree of graphitization of carbon materials can also be characterized by their "d-spacer". The average lattice spacing d(002) of this disclosure is defined as the average distance between adjacent hexagonal rings along the c-axis, determined by XRD (002) diffraction peaks. The d(002) spacing can be calculated using Bragg's law using the following formula:

[0076] d = λ / (2Sinθ)

[0077] Where: λ = wavelength of the radiation source (for copper, λ is...) ), θ = diffraction angle (in degrees) (peak 002), d = distance between two carbon layer planes.

[0078] In the art, carbon materials with a d-spacing of less than or equal to about 0.3500 nm are generally considered to be graphitic carbon (0.3504 nm). The conductive carbon black of this disclosure has a d(002) spacing ≤ 0.3546 nm, such as 0.3503 to 0.3546 nm, which is significantly reduced compared to the d(002) spacing of existing carbon blacks and close to the lattice spacing of graphitic carbon, further demonstrating the high degree of graphitization of the carbon of this disclosure. In different embodiments, the d(002) spacing of the conductive carbon black of this disclosure can be a range of 0.3503 nm, 0.351 nm, 0.3515 nm, 0.352 nm, 0.3525 nm, 0.353 nm, 0.3535 nm, 0.354 nm, 0.3544 nm, 0.3546 nm, or any combination thereof.

[0079] In specific embodiments of this disclosure, the average pore size of the conductive carbon black is 9.63 to 10.56 nm, such as a range of 9.63 nm, 9.7 nm, 9.8 nm, 9.9 nm, 10 nm, 10.04 nm, 10.56 nm, or any combination thereof.

[0080] In a specific embodiment of this disclosure, the volume of pores with a size of 2–50 nm in the conductive carbon black, as measured by nitrogen desorption, is 0.1238–0.3147 cm³. 3 / g, such as 0.1238cm 3 / g, 0.14cm 3 / g, 0.16cm 3 / g, 0.18cm 3 / g, 0.2cm 3 / g, 0.25cm 3 / g, 0.28cm 3 / g, 0.3cm 3 / g, 0.3031cm 3 / g, 0.3147cm 3 / g or a range consisting of any two of them.

[0081] In specific embodiments of this disclosure, the volume of pores with a size of 2 to 50 nm in the conductive carbon black accounts for more than 86.87% of the total pore volume, such as 86.87% to 90.6%. In different embodiments, the proportion of the volume of pores with a size of 2 to 50 nm to the total pore volume can be 86.87%, 87%, 87.99%, 88.5%, 89%, 89.13%, 90%, 90.6%, or any combination thereof.

[0082] In a specific embodiment of this disclosure, the total pore volume of the conductive carbon black is 0.1238–0.3147 cm³. 3 / g, such as 0.2624~0.3147cm 3 / g. In different embodiments, the total pore volume of the conductive carbon black can be 0.1238 cm³. 3 / g, 0.145cm 3 / g, 0.165cm 3 / g, 0.185cm 3 / g, 0.205cm 3 / g, 0.255cm 3 / g, 0.2624cm 3 / g, 0.285cm 3 / g, 0.3031cm 3 / g, 0.3147cm 3 / g or a range consisting of any two of them.

[0083] This disclosure tests pore parameters according to the method of GB / T19587-2004. Specifically, the nitrogen adsorption method is used to test the pore size distribution. The sample is degassed under vacuum at 250℃ for 2 hours, and then the adsorption and desorption performance of the sample for N2 is measured in the range of p / p0 0 to 1 at liquid nitrogen (77K). The specific surface area of ​​carbon black is determined by the multi-point BET method, the micropore area and micropore volume of the sample are analyzed by the t-plot method, and the pore size distribution of carbon black is calculated by the DFT method (N2@77K in carbon slit pore QSDFT adsorption branch model). The pore volume of the conductive carbon black disclosed in this disclosure can reach up to 0.3147 cm³. 3 The proportion of mesoporous (2-50nm) pore volume is above 86.87%, indicating that the conductive carbon black of this disclosure has a well-developed pore structure, which endows the conductive carbon black of this disclosure with excellent liquid absorption and retention capabilities.

[0084] This disclosure also provides a method for preparing any of the above-mentioned conductive carbon black, comprising the following steps:

[0085] In an environment containing plasma and isolated from air, gaseous hydrocarbons undergo thermal decomposition under the action of a microwave plasma generator to form carbon black.

[0086] The disclosed method for preparing conductive carbon black utilizes a microwave plasma generator to provide plasma heating during pyrolysis, increasing the temperature and promoting nucleation. This increases the number of nuclei, i.e., the number of particles with nucleated modes, resulting in a smaller overall particle size of the primary particles. This facilitates the formation of small-particle, chain-like, high-structure carbon black and improves the graphitization degree of the carbon black. The main driving forces for carbon black particle agglomeration in the reaction flow field are Brownian motion and turbulence. Turbulent agglomeration is the agglomeration behavior that occurs when particles move with the fluid in the flow field. During the formation and growth of carbon black particles, nucleation, surface growth, and collision are directly related to the final morphology of the particle aggregates. Ambient temperature, pressure, flow characteristics, and the type of pyrolysis feedstock directly affect the microstructure and structural properties of the pyrolysis products. The production method employed in this disclosure has a higher reaction temperature, resulting in a smaller fractal dimension of the carbon black particles, a more porous, media-like structure, and a more complex aggregate morphology, thus improving the structure of the carbon black.

[0087] Meanwhile, gaseous hydrocarbons generate high-temperature soot during high-temperature cracking. The medium gas that generates plasma produces plasma gas under the action of a microwave plasma generator. This plasma gas mixes with the high-temperature soot, diluting the soot and reducing the collision and bonding between carbon atoms, thereby inhibiting the growth of primary carbon black particles and aggregates.

[0088] Furthermore, the addition of the medium gas for plasma generation, under the action of the microwave plasma generator, produces plasma gas, which introduces a certain amount of atoms (such as hydrogen atoms) into the reaction zone. These atoms can combine with the dangling bonds at the edges of the carbon clusters on the carbon black surface, slowing down and preventing the curling and closing of the carbon clusters to form a spherical surface of the carbon black. This inhibits the growth of primary carbon black particles and increases the specific surface area and structure of the carbon black. In addition, under the action of the microwave plasma generator, the formation of the plasma region expands the reaction formation zone of the carbon black, further increasing the reaction time and prolonging the residence time of carbon black particles, increasing the collision opportunities and facilitating the formation of a well-developed branched structure in the carbon black.

[0089] In practice, gaseous hydrocarbons and air or oxygen can be introduced into the system beforehand. The system is first heated to a certain temperature (the temperature at which thermal decomposition can occur, such as about 850°C) by combustion. Then, after stopping the introduction of air or oxygen for a period of time, the system is isolated from air. The gaseous hydrocarbons are then subjected to thermal decomposition reaction in an environment containing plasma and isolated from air, under the action of a microwave plasma generator.

[0090] In a specific embodiment of this disclosure, during the thermal pyrolysis reaction, the temperature of the plasma reaction zone is controlled to be 3000–3500°C.

[0091] During the thermal pyrolysis reaction, the temperature of the plasma reaction zone can be controlled by adjusting the microwave plasma generator to 3000–3500℃, thereby increasing the graphitization degree of the carbon black. For example, the temperature of the plasma reaction zone can be controlled within a range of 3000℃, 3100℃, 3200℃, 3300℃, 3400℃, 3500℃, or any combination thereof.

[0092] In a specific embodiment of this disclosure, the gaseous hydrocarbon flow direction is arranged at an angle to the flow direction of the plasma-generating medium gas. Further, the angle is 30° to 45°.

[0093] Setting the included angle can prevent the presence of a reflux zone and terminate the reaction. In different embodiments, the included angle can be 30°, 32°, 35°, 38°, 40°, 43°, 45° or any combination thereof. In subsequent specific embodiments, unless otherwise specified, the included angle is 45°, but it is not limited to this.

[0094] In specific embodiments of this disclosure, the gaseous hydrocarbon includes at least one selected from acetylene, toluene, benzene, ethylene, propylene, and butadiene, preferably acetylene.

[0095] In specific embodiments of this disclosure, the medium gas for generating plasma includes at least one of hydrogen, nitrogen, and argon, preferably hydrogen.

[0096] In a specific embodiment of this disclosure, the flow rate ratio of gaseous hydrocarbons to the plasma-generating medium gas is (4 to 13.5):1.

[0097] In different embodiments, the flow ratio of gaseous hydrocarbons to the plasma-generating medium gas can be a range of 4:1, 6.7:1, 10:1, 12:1, 13.3:1, 13.5:1, or any combination thereof.

[0098] In a specific embodiment of this disclosure, the reaction further includes: introducing a cooling gas at the end of the reaction zone to cool the carbon black formed by the thermal decomposition reaction, thereby terminating the reaction. Further, the cooling gas includes at least one of hydrogen, nitrogen, and argon.

[0099] This disclosure further introduces cooling gas at the end of the reaction zone to cool the carbon black in the reaction zone and quickly blow it into the cooling section to terminate the excessive growth of the carbon black.

[0100] This disclosure also provides an apparatus for implementing any of the above-described methods for preparing carbon black, as shown in FIG1, comprising: a pyrolysis furnace body 10, wherein a reaction chamber 11 is formed inside for carrying out a thermal pyrolysis reaction, including the occurrence and termination of thermal pyrolysis; and a microwave plasma generator 20. The cavity structure of the reaction chamber 11 is adaptable to the structure of the pyrolysis furnace body 10.

[0101] The pyrolysis furnace body 10 forms a furnace head 12 and a cooling section 16, with the outlet of the furnace head 12 connected to the inlet of the cooling section 16. As shown in the diagram, the furnace head 12 is used for the thermal pyrolysis of gaseous hydrocarbon feedstock to produce carbon black, and the cooling section 16, formed at the outlet end of the furnace head 12, is used for cooling and collecting the carbon black. Furthermore, the pyrolysis furnace body 10 has a discharge port 17 at the end of the reaction chamber 11 furthest from the furnace head 12, i.e., the discharge port 17 is located at the bottom of the cooling section 16. After the reaction is complete, the produced carbon black leaves the reaction chamber 11 through the discharge port 17.

[0102] The furnace head 12 is provided with two nozzles 13 that communicate with the reaction chamber 11 and at least one first gas inlet pipe 14 that communicates with the reaction chamber 11. The first gas inlet pipe 14 is used to introduce a medium gas for generating plasma into the reaction chamber 11.

[0103] As shown in Figure 2, the two nozzles 13 include a first nozzle 131 and a second nozzle 132. The first nozzle 131 is used to introduce oxygen, air, or gaseous hydrocarbons into the reaction chamber 11, and the second nozzle 132 is used to introduce gaseous hydrocarbons into the reaction chamber 11. The first nozzle 131 and the second nozzle 132 are located on opposite sides of the furnace head 12 and close to one end of the furnace head 12. The central axes of the first nozzle 131 and the second nozzle 132 are perpendicular to the central axis of the furnace head 12. The spray directions of the first nozzle 131 and the second nozzle 132 are opposite and tangential to the circumference of the furnace head 12, thereby causing less backflow and more uniform mixing of the gas delivered by the first nozzle 131 and the second nozzle 132 on the inner wall of the furnace head 12.

[0104] Furthermore, the two nozzles 13 can extend into the reaction chamber 11 respectively, so as to send gas into the reaction chamber 11 and ensure the smooth progress of the thermal decomposition reaction.

[0105] In actual operation, oxygen or air can be introduced first through the first nozzle 131, and gaseous hydrocarbons can be introduced through the second nozzle 132. Combustion will bring the furnace head 12 to a certain temperature (e.g., 850°C) to preheat the pyrolysis furnace. Then, after the oxygen or air supply is cut off for a period of time, gaseous hydrocarbons are introduced through the first nozzle 131 and the second nozzle 132. At the same time, the medium gas for generating plasma is introduced through the first gas inlet pipe 14, and the microwave plasma generator 20 is turned on to cause the pyrolysis reaction.

[0106] The microwave plasma generator 20 is positioned corresponding to the first gas inlet pipe 14 to generate plasma within the reaction chamber 11. The microwave plasma generator 20 acts within the furnace head 12 to form a plasma zone, and its corresponding positioning with the first gas inlet pipe 14 further facilitates the plasmaification of the medium gas used to generate the plasma, thereby expanding the reaction formation area of ​​the carbon black.

[0107] In a specific embodiment of this disclosure, two first gas inlet pipes 14 may be included, which are arranged opposite to each other on both sides of the furnace head 12. Further, the central axis of each first gas inlet pipe 14 is arranged at an angle to the central axis of the furnace head 12. Further, the angle is 45° to 60°.

[0108] In different embodiments, the angle between the central axis of the first gas inlet pipe 14 and the central axis of the furnace head 12 can be 45°, 48°, 50°, 52°, 55°, 58°, 60° or any combination thereof. Unless otherwise specified in subsequent specific embodiments, the angle here is 45°, but it is not limited to this.

[0109] In a specific embodiment of this disclosure, two microwave plasma generators 20 may be included, which are arranged opposite to each other on both sides of the furnace head 12. Further, the outlet of each microwave plasma generator 20 is arranged at an angle to the central axis of the furnace head 12. The angle is 45° to 60°.

[0110] In different embodiments, the angle between the outlet of the microwave plasma generator 20 and the central axis of the furnace head 12 can be 45°, 48°, 50°, 52°, 55°, 58°, 60° or any combination thereof. Unless otherwise specified in subsequent specific embodiments, the angle here is 45°, but it is not limited to this.

[0111] In practice, the type of microwave plasma generator can be adjusted and selected according to actual needs, as long as it can achieve the corresponding function. Specific microwave plasma generators may include magnetrons, circulators, couplers, tuners, waveguides (such as tapered waveguides) and resonators, but are not limited to these.

[0112] In a specific embodiment of this disclosure, at least one second gas inlet pipe 15 is also included, which is connected to the reaction chamber 11. The second gas inlet pipe 15 is located at the furnace head 12 and near the outlet of the furnace head 12. The second gas inlet pipe 15 is used to introduce cooling gas to cool the carbon black in the reaction zone and to quickly blow it into the cooling section 16 to terminate carbon black growth.

[0113] In a specific embodiment of this disclosure, two second gas inlet pipes 15 may be included, which are arranged opposite to each other on both sides of the furnace head 12. Further, the central axis of each second gas inlet pipe 15 is arranged at an angle to the central axis of the furnace head 12. The angle is 45° to 60°.

[0114] In different embodiments, the angle between the central axis of the second gas inlet pipe 15 and the central axis of the furnace head 12 can be 45°, 48°, 50°, 52°, 55°, 58°, 60° or any combination thereof. Unless otherwise specified in subsequent specific embodiments, the angle here is 45°, but it is not limited to this.

[0115] This disclosure also provides an electrode paste, including any of the above-mentioned conductive carbon blacks.

[0116] When carbon black is used in electrode paste, it can be used as the sole conductive material or in combination with other conductive materials. The ratio of these materials can be adjusted according to actual needs.

[0117] This disclosure also provides a secondary battery, including a positive electrode, a negative electrode, an electrolyte, and a separator; at least one of the positive and negative electrodes is made from any of the aforementioned electrode slurries.

[0118] The types of positive electrode active material, negative electrode active material, electrolyte, and separator can be adjusted according to actual needs and are not limited to one type. The following embodiments are only illustrated by one type of active material, electrolyte, and separator, and are not intended to limit these types.

[0119] Examples 1-4

[0120] Examples 1-4 provide a method for preparing high-structure, high-specific-surface-area conductive carbon black based on high crystallinity, using the equipment shown in Figure 1, and including the following steps:

[0121] (1) Acetylene gas at 30 Nm 3 / h flow rate and oxygen at 50Nm 3 The oxygen is supplied through the pyrolysis furnace 10 at a flow rate of / h, so that it is burned and heated to 850°C to preheat the furnace body 10; wherein, oxygen is supplied through the first nozzle 131 and acetylene is supplied through the second nozzle 132.

[0122] (2) Continue to supply acetylene gas through the second nozzle 132; after cutting off the oxygen supply for a period of time, and ensuring that the pyrolysis furnace is isolated from air, supply acetylene gas from the first nozzle 131. The flow rate of the acetylene gas is 80-200 Nm³. 3 / h; Simultaneously, hydrogen is supplied through the first gas inlet pipe 14, the microwave plasma generator is turned on to generate plasma from the hydrogen, and the temperature of the plasma reaction zone is controlled at 3000-3500℃, with a hydrogen gas flow rate of 15-20 Nm³. 3 / h.

[0123] (3) Acetylene is cracked and passes through a high-temperature plasma region to generate carbon black in the reaction chamber 11. Then, it is cooled and carried by hydrogen gas in the second gas inlet pipe 15 into the cooling section for collection, thereby producing carbon black.

[0124] In the preparation methods of Examples 1 to 4, the flow rates of acetylene gas and hydrogen gas and the temperature of the plasma reaction zone in step (2) are shown in Table 1.

[0125] Table 1. Flow rate and temperature information for different embodiments

[0126] Example 5

[0127] This embodiment provides a method for preparing electrode paste, including the following steps:

[0128] The positive electrode active material LiCoO2, polyvinylidene fluoride and carbon black were weighed in a mass ratio of 96:2:2 and mixed evenly in an appropriate amount of N-methylpyrrolidone to obtain an electrode slurry. The carbon black in each electrode slurry was the conductive carbon black obtained in Examples 1 to 4, and the corresponding electrode slurries were numbered Example 5-1, Example 5-2, Example 5-3 and Example 5-4, respectively.

[0129] Example 6

[0130] This embodiment provides a method for preparing a battery, including the following steps:

[0131] Electrode slurry was coated onto a 20 μm thick aluminum foil (current collector), dried, rolled, and cut to form a positive electrode sheet. A lithium metal sheet was used as the counter electrode. A separator (Celgard 2500) and an electrolyte (1 mol / L lithium hexafluorophosphate dissolved in a 1:1:1 volume ratio of dimethyl carbonate (DMC) / ethylene carbonate (EC) / ethyl methyl carbonate (EMC)) were used to prepare a button cell. The electrode slurries used in each button cell were the four electrode slurries obtained in Example 5, and the corresponding cell numbers are Example 6-1, Example 6-2, Example 6-3, and Example 6-4, respectively.

[0132] Comparative Example 1

[0133] Comparative Example 1 provides a commercially available carbon black.

[0134] Comparative Example 1 also provides an electrode slurry, which is prepared in accordance with the method of Example 5, except that the carbon black is replaced with an equal weight of commercially available carbon black. The resulting electrode slurry is designated as Comparative Example 1-1.

[0135] Comparative Example 1 also provides a battery, which is prepared in accordance with the preparation method of Example 6, except that the electrode slurry is replaced with an equal weight of electrode slurry Comparative Example 1-1, and the resulting battery is designated as Comparative Example 1-2.

[0136] Experimental Example 1

[0137] The OAN and cOAN of carbon black from different examples and comparative examples were determined according to the standard method of "GB / T 3780.2-2017 Carbon Black Part 2: Determination of Oil Absorption Value", and the structural change rate X (X=(OAN-cOAN) / OAN) was calculated. The specific results are shown in Table 2.

[0138] Table 2. OAN, cOAN, and structural change rate of carbon black in different embodiments and comparative examples.

[0139] As shown in Table 2, the conductive carbon black of this disclosure has a co-anchoring density (cOAN) of over 108 mL / 100 g, ensuring that the carbon black, when used as a conductive agent, possesses sufficient length, a well-developed network structure, and excellent liquid absorption and retention capabilities, resulting in good conductivity and ionic conductivity. The conductive carbon black of this disclosure has a cOAN of less than 180 mL / 100 g, which suppresses the aggregation caused by the entanglement of aggregate structures into larger agglomerates, resulting in good dispersibility. Furthermore, the structural change rate of the conductive carbon black of this disclosure is between 48.6% and 55%, enabling the carbon black to balance liquid absorption and retention capabilities, conductivity, and dispersibility, thereby improving battery performance when applied to electrodes.

[0140] The BET specific surface area and pore parameters of carbon black from different examples and comparative examples were further tested according to the method of GB / T 19587-2004. Specifically, the specific surface area and pore size distribution of carbon black were determined by nitrogen adsorption. The samples were degassed under vacuum at 250℃ for 2 h, and then the adsorption and desorption performance of the samples for N2 was measured at liquid nitrogen (77K) in the range of p / p0 0 to 1. The specific surface area of ​​carbon black was determined by multi-point BET method, the micropore area and micropore volume of the samples were analyzed by t-plot method, and the pore size distribution of carbon black was calculated by DFT method (N2@77K in carbon slit pore QSDFT adsorption branch model). The specific results are shown in Table 3.

[0141] Table 3. BET specific surface area and pore parameters of carbon black from different embodiments and comparative examples.

[0142] As can be seen from the above data, the pore volume of the carbon black in this embodiment is as high as 0.3147 cm³. 3The carbon black has a surface area of ​​ / g, and the proportion of mesoporous (2-50nm) pore volume is above 86.87%, indicating a more developed mesoporous structure. The BET specific surface area reflects the development of the pore structure of carbon black. The BET specific surface area disclosed in this invention is within the above range, indicating that the carbon black has a well-developed pore structure and branched structure, increasing the number of contact points with other substances (such as active materials in electrodes), thus fully utilizing the conductivity of carbon black; simultaneously, it possesses high conductivity-conducting ability due to its percolation effect in electrode materials.

[0143] The average particle size of the primary particles of carbon black is obtained by averaging the particle sizes measured using photographs taken with a transmission electron microscope or similar instruments. The average particle size of the primary particles of the conductive carbon black disclosed herein is 26–45 nm. Specifically, the average particle sizes of the primary particles of the carbon black in Examples 1–4 are shown in Table 4.

[0144] Table 4. Average particle size of primary particles of carbon black in different embodiments and comparative examples.

[0145] Experiment Example 2

[0146] Raman spectroscopy tests were performed on the carbon black samples from different embodiments and comparative examples. The specific test method was as follows: using a laser Raman spectroscopy device, several carbon black samples were placed on a glass slide and scraped repeatedly with a scraper until flat. The tests were conducted under the following conditions: YAG laser (excitation wavelength): 514 nm, number of lines: 600 gr / mm, filter: D0.6, objective lens magnification: 100x, exposure time: 150 seconds, cumulative exposures: 2. Figures 3 to 7 show the Raman spectra of the carbon black prepared in Examples 1 to 4 of this disclosure and the carbon black of Comparative Example 1, respectively.

[0147] As shown in the figure, the Raman spectrum of the corresponding carbon black has two characteristic peaks: the D Raman scattering peak and the G Raman scattering peak. Specifically, the Raman spectrum of carbon includes peaks at approximately 1340 cm⁻¹. -1 and 1580cm -1 The two main "resonance" bands at this point are designated as "D" and "G" bands, respectively. The D band is generally considered to be attributed to disordered sp... 2 Carbon and the G-band are attributed to graphitic or "ordered" sp. 2 Carbon. Carbon black's graphitization is characterized by its crystallinity, which is measured in Raman spectroscopy as the ratio of the peak area of ​​the G band to the sum of the peak areas of the G and D bands (Sg). G / S G+DThe conductive carbon black prepared in Examples 1-4 of this disclosure has a crystallinity of 49%, 51%, 45%, and 42%, respectively, as measured by Raman spectroscopy, while the crystallinity of the carbon black in Comparative Example 1 is 38%. This indicates that the conductive carbon black prepared in this disclosure can achieve a high degree of graphitization. Therefore, when using the conductive carbon black of this disclosure as a conductive agent, the high degree of graphitization of the carbon black can improve the conductivity of the electrode active material or enhance the stability of the material, improve compatibility with the electrolyte, and thus ensure battery performance.

[0148] Figure 8 shows the X-ray diffraction (XRD) patterns of carbon black from Examples 1-4 and Comparative Example 1 of this disclosure. Graphite is a carbon black in which carbon atoms have sp... 2 The crystalline form of carbon with hybrid bonds, carbon atoms in graphite are arranged in essentially planar hexagonal rings, stacked in, for example, ABAB or ABCABC order. XRD analysis of graphite shows main diffraction peaks on the (002), (10), (004), and (110) planes. Calculations based on the XRD data in Figure 8 show that the average lattice spacing d(002) of the conductive carbon black prepared in Examples 1-4 of this disclosure are 0.3525 nm, 0.3503 nm, 0.3544 nm, and 0.3546 nm, respectively, which are close to the lattice spacing of graphite carbon and consistent with the analysis results of Raman spectroscopy, indicating that the conductive carbon black prepared in Examples 1-4 of this disclosure has excellent stability. In addition, the average lattice spacing d(002) of the carbon black in Comparative Example 1 is 0.3601 nm. The average lattice spacing d(002) of the carbon black in this embodiment is much smaller than that of the carbon black in Comparative Example 1, indicating that the degree of graphitization of the conductive carbon black in this embodiment is significantly higher than that of the carbon black in Comparative Example 1.

[0149] Further calculations based on the XRD data in Figure 8 show that the crystallite sizes Lc of the conductive carbon black prepared in Examples 1-4 of this disclosure are respectively... The crystallite size Lc of the carbon black in Comparative Example 1 is... The conductive carbon black of this disclosure has a significantly increased crystallite size Lc compared to the carbon black of Comparative Example 1, which further indicates that the carbon black prepared in this disclosure has a higher degree of graphitization than that of Comparative Example 1. This is consistent with the analysis of Raman spectroscopy and average lattice spacing d(002).

[0150] Experimental Example 3

[0151] The parameters of the electrode slurries prepared in Example 5 and Comparative Example 1 were tested, and the test results are shown in Table 5.

[0152] Table 5. Parameter test results for different electrode pastes

[0153] The above-mentioned parameter testing methods include: using a battery slurry solid content analyzer to obtain the solid content of the sample by the ratio of the weight of the dried sample after heating to the weight of the wet sample before heating, which is to determine the solid content of each slurry; and using an NDJ-9s viscosity meter with rotor No. 3 and a rotation speed of 12 rpm to measure the viscosity of each electrode slurry at 25℃.

[0154] As shown in Table 5, with similar solid content, the viscosity of the electrode slurries prepared from the carbon blacks of Examples 1-4 is significantly lower than that of the electrode slurry prepared from the carbon black of Comparative Example 1. This indicates that the conductive carbon blacks prepared in Examples 1-4 of this disclosure have excellent dispersibility. When mixed with active materials and binders, they are less likely to form agglomerates and are easily sheared during dispersion treatment, thus forming electrode slurries with relatively low viscosity. Furthermore, the shearing process during slurry preparation can form a uniformly dispersed electrode slurry without severely damaging the primary structure of the carbon black, which can greatly improve the characteristics of the corresponding secondary batteries.

[0155] The batteries prepared in Example 6 and Comparative Example 1 were further subjected to performance tests, and the test results are shown in Figure 9. The battery rate performance test method included: allowing the prepared batteries to stand for 12 hours, then aging them three times at 25°C with a charge / discharge rate of 0.1C within a voltage range of 4.35-2.8V using a Newway battery testing system, followed by charging at a 0.5C rate, and discharging at rates of 0.2C, 0.5C, 1C, 2C, 3C, 5C, 6C, 8C, and 10C within a voltage range of 4.35-2.8V.

[0156] According to the rate performance test results in Figure 9, the batteries numbered Example 6-1, Example 6-2, Example 6-3, and Example 6-4 have discharge capacities of 88.41%, 89.11%, 93.4%, and 94.33% of their initial capacities at a 10C rate, respectively. The battery numbered Comparative Example 1 has a discharge capacity of 82.73% of its initial capacity at a 10C rate. This indicates that the conductive carbon black prepared in Examples 1-4 of this disclosure is uniformly dispersed in the battery and the sheet, coating the surface of lithium cobalt oxide. The high crystallinity makes the conductive network formed by it more conductive, and the low structural change rate gives the prepared carbon black better liquid absorption and retention capabilities, which is more conducive to lithium ion transport and reduces the polarization degree inside the battery. The highly crystalline conductive carbon black reduces the side reactions of the electrolyte and lithium cobalt oxide inside the battery, improves the compatibility with the electrolyte, and is more conducive to the battery capacity utilization, thereby improving the rate performance of the battery.

[0157] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this disclosure, and are not intended to limit them. Although this disclosure has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this disclosure. Industrial applicability

[0158] The conductive carbon black disclosed herein possesses high crystallinity, high structure, and high specific surface area. When used as a conductive agent, its high crystallinity endows it with excellent conductivity and stability, as well as improved compatibility with electrolytes. Furthermore, its structure has sufficient length, a perfect network structure, and liquid absorption and retention capabilities, resulting in good conductivity, ion conduction, and dispersibility, which can significantly improve battery performance. At the same time, the preparation method of the conductive carbon black disclosed herein is simple to operate and suitable for large-scale production.

Claims

1. A highly crystalline, high-structure, high-specific-surface-area-conductive carbon black, characterized in that, The conductive carbon black has a crystallinity of 42%–51% and a BET specific surface area of ​​58–200 m². 2 / g, COAN is 108~180mL / 100g.

2. The high-crystallinity, high-structure, high-specific-surface-area-conductive carbon black according to claim 1, characterized in that, The conductive carbon black has an OAN of 240–350 mL / 100 g.

3. The high-crystallinity, high-structure, high-specific-surface-area conductive carbon black according to claim 1 or 2, characterized in that, The structural change rate X of the conductive carbon black is 48.6% to 55%; wherein, the structural change rate X = (OAN - cOAN) / OAN.

4. The high-crystallinity, high-structure, high-specific-surface-area-conductive carbon black according to any one of claims 1-3, characterized in that, The conductive carbon black has a crystallinity of 45% to 51%.

5. The high-crystallinity, high-structure, high-specific-surface-area conductive carbon black according to any one of claims 1-4, characterized in that, Satisfy at least one of the following characteristics: (1) The crystallite size Lc of the conductive carbon black is (2) The average lattice spacing d(002) of the conductive carbon black is ≤0.3546 nm; Preferably, the average lattice spacing d(002) of the conductive carbon black is 0.3503 to 0.3546 nm.

6. The high-crystallinity, high-structure, high-specific-surface-area conductive carbon black according to any one of claims 1-5, characterized in that, The average particle size of the primary particles of the conductive carbon black is 26–45 nm.

7. The high-crystallinity, high-structure, high-specific-surface-area conductive carbon black according to any one of claims 1-6, characterized in that, Satisfy at least one of the following characteristics: (1) The average pore size of the conductive carbon black is 9.63–10.56 nm; (2) The conductive carbon black, measured by nitrogen desorption, has pore volumes of 0.1089–0.2851 cm³ with sizes ranging from 2 to 50 nm. 3 / g; (3) In the conductive carbon black, the volume of pores with a size of 2 to 50 nm accounts for more than 86.87% of the total pore volume; Preferably, in the conductive carbon black, the volume of pores with a size of 2 to 50 nm accounts for 86.87% to 90.6% of the total pore volume.

8. The method for preparing high-structure, high-specific-surface-area conductive carbon black based on high crystallinity according to any one of claims 1 to 7, characterized in that, Includes the following steps: In an environment containing plasma and isolated from air, gaseous hydrocarbons undergo thermal decomposition under the action of a microwave plasma generator to form carbon black.

9. The preparation method according to claim 8, characterized in that, During the thermal decomposition reaction, the temperature of the plasma reaction zone is controlled at 3000–3500°C.

10. The preparation method according to claim 8 or 9, characterized in that, The gaseous hydrocarbon flow direction is arranged at an angle to the flow direction of the medium gas that generates the plasma. Preferably, the included angle is 30° to 45°.

11. The preparation method according to any one of claims 8-10, characterized in that, The gaseous hydrocarbon includes at least one of acetylene, toluene, benzene, ethylene, propylene, and butadiene; Preferably, the gaseous hydrocarbon is acetylene; Preferably, the medium gas used to generate the plasma includes at least one of hydrogen, nitrogen, and argon.

12. The preparation method according to any one of claims 8-11, characterized in that, The flow rate ratio of the gaseous hydrocarbon to the medium gas that generates the plasma is (4–13.5):

1.

13. The preparation method according to any one of claims 8-12, characterized in that, Also includes: Cooling gas is introduced at the end of the reaction zone to cool the carbon black formed by the thermal cracking reaction, thereby terminating the reaction. Preferably, the cooling gas includes at least one of hydrogen, nitrogen, and argon.

14. An apparatus for carrying out the preparation method according to any one of claims 8 to 13, characterized in that, include: The pyrolysis furnace body has a reaction chamber inside; and a microwave plasma generator; The pyrolysis furnace body forms a furnace head and a cooling section, with the outlet of the furnace head connected to the inlet of the cooling section; the furnace head is provided with two nozzles communicating with the reaction chamber and at least one first gas inlet pipe communicating with the reaction chamber; The microwave plasma generator is configured correspondingly to the first gas inlet pipe to generate plasma within the reaction chamber.

15. The device according to claim 14, characterized in that, It also includes at least one second gas inlet pipe communicating with the reaction chamber; the second gas inlet pipe is opened at the furnace head and near the outlet of the furnace head; Preferably, it includes two second gas inlet pipes, which are arranged opposite to each other on both sides of the furnace head.

16. The device according to claim 14 or 15, characterized in that, It includes two first gas inlet pipes, which are arranged opposite to each other on both sides of the furnace head; Preferably, the central axis of each of the first gas inlet pipes is set at an angle to the central axis of the furnace head; Preferably, the included angle is 45° to 60°.

17. The device according to any one of claims 14-16, characterized in that, It includes two microwave plasma generators, which are arranged opposite each other on both sides of the furnace head.

18. An electrode paste, characterized in that, Includes the high-crystallinity, high-structure, high-specific-surface-area conductive carbon black based on any one of claims 1 to 7, or the high-crystallinity, high-structure, high-specific-surface-area conductive carbon black prepared by the preparation method according to any one of claims 8 to 13.

19. A secondary battery, characterized in that, It includes a positive electrode, a negative electrode, an electrolyte, and a separator; at least one of the positive electrode and the negative electrode is made from the electrode slurry of claim 18.

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