Method for post-processing carbon black and carbon black post-processed by method

Abstract

The present invention relates to a method for post-processing a carbon black and a carbon black post-processed by the method, and more particularly, to a method for post-processing a wet-granulated furnace black, a carbon black post-processed by the method, and a use thereof.

Description

Technical Field

[0001] The present invention relates to a method for post-treating carbon black and the carbon black post-treated by the method, and more particularly, to a method for post-treating wet-pelleted furnace carbon black in carbon black and the carbon black post-treated by the method. Background Art

[0002] Carbon black is an aggregate of very fine spherical particles obtained through the incomplete combustion of hydrocarbon or carbon compounds. Carbon black forms primary particles in a reactor, which then fuse to form aggregates resembling grape bunches. Carbon black can be broadly categorized into acetylene black and furnace black. Furnace black offers the advantage of low cost, but has the disadvantage of difficulty achieving high crystallinity compared to acetylene black.

[0003] Carbon black's physical properties influence the quality of the materials used. These properties include crystallinity, specific surface area, structure, and particle size. These properties can be adjusted through various post-treatments. Carbon black is used in a variety of fields, including industrial paints, coating compositions, and various printed materials. Its electrical properties make it a conductive material for lithium-ion secondary batteries, and if high crystallinity is maintained, it can be used as a catalyst carrier for fuel cells.

[0004] On the other hand, in order to prepare carbon black for industrial / technical products, it is known to use carbon black powder or carbon black pellets (pellets or beads). In this case, carbon black pellets can be divided into wet pelletized forms and dry pelletized forms.

[0005] Carbon black powder has excellent dispersibility in various solvents, but its low bulk density has the disadvantage of low productivity during processes such as heat treatment. Meanwhile, carbon black pellets, while having the advantage of high bulk density, have a larger average particle size and lower dispersibility than carbon black powder, thus hindering their use in slurry preparation.

[0006] Recently, for carbon black used as a material for advanced and diversified secondary batteries, there is a growing demand for the development of physical property requirements that increase with application, as well as technologies for efficiently achieving these requirements at the process level. Summary of the Invention

[0007] Technical issues

[0008] The object of the present invention is to provide a method for effectively post-processing carbon black having excellent physical properties using wet granulated furnace carbon black and the carbon black post-processed by this method.

[0009] The object of the present invention is to provide a high-quality carbon black having reduced surface resistance and reduced impurity content produced by a furnace carbon black production process using wet granulation, and a conductive material for a secondary battery containing the same.

[0010] The object of the present invention is to provide high-quality carbon black having high crystallinity and low impurity content produced by wet-granulated furnace carbon black, and a catalyst support for a fuel cell containing the same.

[0011] The objectives of the present invention are not limited to the objectives mentioned above. Other objectives and advantages of the present invention not mentioned above can be understood from the following description and can be more clearly understood through the embodiments of the present invention. In addition, it is understood that the objectives and advantages of the present invention can be achieved by the means shown in the scope of protection of the invention and their combinations.

[0012] Technical Solution

[0013] In order to achieve the above-mentioned purpose, according to one embodiment of the present invention, a post-processing method of carbon black can be provided, comprising: step (a), preparing wet-granulated furnace carbon black; step (b), high-temperature heat-treating the furnace carbon black in a furnace at a temperature of more than 1200°C; step (c), continuously transferring the high-temperature heat-treated furnace carbon black to a pulverizer; and step (d), crushing the furnace carbon black transferred to the pulverizer to obtain carbon black with an average particle size (diameter) of less than 20 μm.

[0014] The average particle size of the prepared carbon black may be less than 15 μm.

[0015] Atmospheric gas may be added during the high-temperature heat treatment in step (b).

[0016] The atmosphere gas may include one or more of nitrogen (N 2 ) and argon (Ar).

[0017] The total content of metal impurities in the prepared carbon black may be less than 100 ppm.

[0018] The heat treatment temperature may be 2000-2500° C., and the prepared carbon black may be a highly crystalline carbon black having an Lc of 4.0 nm or more.

[0019] The heat treatment temperature may be 1000-1500° C., and the prepared carbon black may be conductive carbon black.

[0020] The transfer in step (c) may be performed through a fluid medium, and the transfer of the furnace carbon black through the fluid medium and the separation of the fluid medium from the transferred furnace carbon black may be performed simultaneously.

[0021] The pulverization in step (d) can be carried out in any one of a high-speed mixer, a ball mill and an air jet mill.

[0022] Furthermore, according to yet another embodiment of the present invention, carbon black post-treated by the carbon black post-treatment method according to one embodiment of the present invention may be provided.

[0023] Furthermore, according to another embodiment of the present invention, a conductive material for a lithium ion secondary battery including carbon black post-treated by the carbon black post-treatment method according to one embodiment of the present invention can be provided.

[0024] Furthermore, according to another embodiment of the present invention, a fuel cell catalyst support including carbon black post-treated by the carbon black post-treatment method according to one embodiment of the present invention can be provided.

[0025] Effects of the Invention

[0026] According to the present invention, wet granulated furnace carbon black can be used to effectively post-process carbon black having excellent physical properties in terms of process and cost.

[0027] The wet-granulated furnace carbon black used in the carbon black preparation method of the present invention can significantly increase the amount of loading in the carbon black preparation process due to its high bulk density, and includes a series of steps that can continuously prepare carbon black, thereby significantly improving productivity.

[0028] The carbon black post-treated according to the carbon black post-treatment method of the present invention can reduce the content of metal impurities and sulfur content, while reducing the surface resistance or significantly improving the crystallinity, and thus has the advantage of being suitable for obtaining carbon black that can be used in various applications requiring high-quality products.

[0029] The specific effects of the present invention will be described together with the above-mentioned effects in the following description of specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 A flow chart briefly shows a method for producing carbon black according to one embodiment of the present invention.

[0031] Figure 2 A scanning electron microscope (SEM) image of the carbon black of Reference Example 1 of the present invention is shown.

[0032] Figure 3 A scanning electron microscope image of the carbon black of Example A of the present invention is shown.

[0033] Figure 4 A scanning electron microscope image of the carbon black of Comparative Example A of the present invention is shown.

[0034] Figure 5 A scanning electron microscope image of the carbon black of Comparative Example B of the present invention is shown.

[0035] Figure 6 A diagram showing the actual coating of the carbon black slurry of Example A of the present invention on an electrode.

[0036] Figure 7 A diagram showing the actual application of the carbon black slurry of Comparative Example A of the present invention on an electrode.

[0037] Figure 8a and Figure 8b Shown are a scanning electron microscope image of a cross section of an electrode prepared using the carbon black slurry of Example A of the present invention and a component distribution map (mapping image) analyzed by a scanning electron microscope-energy dispersive spectrometer (SEM EDS).

[0038] Figure 9a and Figure 9b Shown are a scanning electron microscope image of a cross section of an electrode prepared using the carbon black slurry of Comparative Example A of the present invention and a component distribution diagram analyzed by SEM EDS.

[0039] Figure 10a and Figure 10b Shown are a scanning electron microscope image of the surface of an electrode prepared using the carbon black slurry of Example A of the present invention and a component distribution map analyzed by SEM EDS.

[0040] Figure 11a and Figure 11b Shown are a scanning electron microscope image of the surface of an electrode prepared using the carbon black slurry of Comparative Example A of the present invention and a component distribution map analyzed by SEM EDS.

[0041] Figure 12 A scanning electron microscope image showing a state where the carbon black slurry of Example X of the present invention is applied to an electrode.

[0042] Figure 13 A scanning electron microscope image shows a state where the carbon black slurry of Comparative Example X of the present invention is applied to an electrode.

[0043] Figure 14 An example of a method for analyzing the average particle size of carbon black particles by taking a scanning electron microscope image is shown. DETAILED DESCRIPTION

[0044] The aforementioned objects, features and advantages will be described in detail in the following content with reference to the accompanying drawings, and ordinary technicians in the technical field to which the present invention belongs can easily implement the technical ideas of the present invention based on them.

[0045] In the process of describing the present invention, when it is judged that the detailed description of the known technology related to the present invention may unnecessarily obscure the gist of the present invention, its detailed description will be omitted. Below, the preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the accompanying drawings, the same reference numerals are used to represent the same or similar structural elements.

[0046] In this specification, when referring to a component as "including," "having," "forming," "arranging," or "having," other components may be included unless "only" is used to limit the component. Unless otherwise specified, reference to a component in the singular includes the plural.

[0047] In this specification, when explaining structural elements, unless otherwise specified, they should be interpreted as including a range of error.

[0048] Hereinafter, the present invention will be described in more detail.

[0049] The carbon black post-treatment method of the present invention is characterized by the use of wet-granulated furnace carbon black. As mentioned above, wet-granulated furnace carbon black has the limitation of being difficult to prepare into a slurry due to its low dispersibility. Therefore, despite its cost and process advantages, it is not used in the production of carbon black for battery materials. Instead, carbon black powder is used in the actual production of industrial carbon black.

[0050] After repeated research by the inventors, it was confirmed that while wet-granulated furnace carbon black has the advantage of increasing the amount of material loaded during the process due to its high bulk density, it can also be post-processed by adjusting the heat treatment and pulverization conditions to address the low dispersibility that is a limitation of wet-granulated carbon black. Specifically, the present invention experimentally confirmed the optimal carbon black particle size that can significantly improve dispersibility during slurry preparation. Furthermore, it was confirmed that by increasing the purity of the post-processed carbon black and reducing the sulfur content, environmental protection can be achieved. Depending on the application of the post-processed carbon black, the crystallinity can be increased or the surface resistance can be reduced to ensure that it has various physical properties such as conductivity, thus completing the present invention.

[0051] Specifically, if Figure 1 As shown, the post-processing method of carbon black in one example of the present invention may include the following steps: step (a), preparing wet-granulated furnace carbon black; step (b), high-temperature heat-treating the furnace carbon black at a temperature of more than 1200°C in a furnace; step (c), continuously transferring the high-temperature heat-treated furnace carbon black to a pulverizer; and step (d), pulverizing the furnace carbon black transferred to the pulverizer to obtain carbon black with an average particle size of less than 20 μm.

[0052] In particular, from the perspective of improving dispersibility, the average particle size of the carbon black ultimately obtained by the carbon black post-treatment method of the present invention is preferably 20 μm or less, and more preferably 15 μm or less. The smaller the particle size of the post-treated carbon black, the more advantageous it is, and there is no particular lower limit for the average particle size. Carbon black having an average particle size within this range exhibits excellent dispersibility in the solvent, which can improve processability during slurry preparation.

[0053] The wet-granulated furnace carbon black used in step (a) of the present invention is carbon black wet-granulated in a granulation machine, and is not particularly limited as long as it is furnace carbon black used in the technical field to which the present invention belongs. For example, the average particle size of the wet-granulated furnace carbon black can be about 0.25 to 2.0 mm, and the average bulk density can be about 0.2 to 0.3 g / cm 3 , but not limited to this.

[0054] The step (b) is a heat treatment step for changing the physical properties of carbon black. The purity can be improved by removing impurities such as metals through heat treatment at a high temperature of 1200° C. or higher.

[0055] In order to more effectively remove impurities during the high-temperature heat treatment in step (b), an atmospheric gas may be added. The atmospheric gas may include one or more of nitrogen and argon, preferably nitrogen.

[0056] According to one embodiment of the present invention, the purity of the post-treated carbon black can be improved, and the content of metal impurities and / or sulfur can be reduced.

[0057] According to one example of the present invention, for example, the total content of metal impurities in the post-treated carbon black can be less than 100 ppm, for example, less than 90 ppm, for example, less than 80 ppm, for example, less than 70 ppm, for example, less than 60 ppm, for example, less than 50 ppm, for example, less than 40 ppm, for example, less than 30 ppm, for example, less than 20 ppm, for example, less than 10 ppm.

[0058] The metal impurities are metal elements that may be contained in carbon black, specifically, Al, Ba, Ca, Cd, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Mo, Na, Ni, Pb, Sb, Sn, Sr, Ti, V, and Zn, and can be measured by inductively coupled plasma spectrometry (ICP-OES).

[0059] Furthermore, the sulfur content of the post-treated carbon black is not particularly limited and can be significantly lower than that of the furnace carbon black before post-treatment. The specific sulfur content can be adjusted according to the application of the post-treated carbon black.

[0060] According to an example of the present invention, for example, the sulfur content of the post-treated carbon black can be 3000 ppm or less, for example, 2000 ppm or less, for example, 1000 ppm or less, for example, 500 ppm or less.

[0061] Furthermore, by adjusting the heat treatment temperature in the heat treatment step (b), the surface properties of the carbon black can be adjusted according to the intended use of the carbon black.

[0062] According to one embodiment of the present invention, in order to ensure electrical conductivity by reducing the surface resistance compared to that before post-treatment, preferably, the heat treatment temperature of step (b) is 1200-1800°C, more preferably, 1200-1500°C.

[0063] On the other hand, in order to improve the crystallinity of carbon black, the heat treatment temperature in step (b) is preferably 2000-2500° C., more preferably 2300-2500° C. In particular, as an indicator for confirming the high crystallinity of carbon black, a large crystallite size Lc value is preferred.

[0064] Specifically, in the present invention, for example, the Lc of the post-treated carbon black can be above 4.0 nm, for example, Lc can be above 5.0 nm, for example, Lc can be above 6.0 nm. If it is above 4.0 nm, it can be evaluated as having very high crystallinity. The carbon black post-treatment method according to the present invention has the advantage of obtaining highly crystalline carbon black.

[0065] In the step (c), the heat-treated furnace carbon black is transferred to the pulverizer for pulverization. The transfer in the present invention can be performed by a fluid medium. The fluid medium is not particularly limited, but for the convenience of the process, it can contain air. In addition, the transfer of the furnace carbon black through the fluid medium and the separation of the fluid medium from the transferred furnace carbon black can be performed simultaneously, so that the productivity of the process can be improved by continuously post-processing the carbon black. In addition, in the carbon black post-processing method of the present invention, the amount of material loaded per post-processing step can be significantly increased by using wet granulated carbon black. Even if a large amount of material is loaded (put in) at one time, the physical properties of the target carbon black can be ensured. Therefore, these process advantages can be achieved at the same time, thereby improving the convenience and productivity of the process.

[0066] For example, a pulse jet bag filter is preferably used as the device for continuously transferring and separating the furnace carbon black subjected to the above-mentioned heat treatment. This device can continuously transfer the furnace carbon black using air as a medium through vacuum, and has the advantage of automatically separating the air after transfer, allowing the process to be carried out efficiently and continuously.

[0067] In the step (d), the heat-treated furnace carbon black is pulverized, as described above, preferably to an average particle size of 20 μm or less, more preferably 15 μm or less. The pulverization method or apparatus is not particularly limited. For example, a high-speed mixer, a ball mill, or a jet mill can be used as the pulverizer. From the perspective of the convenience of pulverization, a jet mill is preferably used.

[0068] The carbon black of the present invention that has been post-treated as described above can be used in products requiring high-quality carbon black, such as conductive materials for lithium-ion secondary batteries and catalyst supports for fuel cells.

[0069] Modes for Carrying Out the Invention

[0070] The present invention will be described in more detail below through examples and experimental examples. However, the following examples and experimental examples are only used to illustrate the present invention, and the content of the present invention is not limited to the following examples and experimental examples.

[0071] Example

[0072] Part 1 - Heat Treatment Process Test: Examples 1 to 8 and Comparative Examples 1 to 3

[0073] Wet-granulated furnace carbon black (DC3501 (OCI)) or powdered furnace carbon black (DC3501 (OCI)) was prepared and heat-treated in batches in a heat-resistant furnace. Specifically, the carbon black was placed (loaded) at approximately 70 volume percent (vol%) in a graphite crucible, heated at a rate of 5°C / min, and heat-treated for one hour at the maximum temperature shown in Table 1 below. Nitrogen or argon was added as the atmosphere gas.

[0074] Table 1

[0075]

[0076] The physical properties of the heat-treated carbon blacks in Examples 1 to 8 and Comparative Examples 1 to 3 were measured according to the following (1) to (5), and the results are shown in Table 2 below.

[0077] (1) Specific surface area: The specific surface area was analyzed by nitrogen adsorption using the Brunauer-Emmett-Teller (BET) formula (analysis equipment: Micromeritics ASAP 2460).

[0078] (2) Crystallinity, Lc(200): X-ray diffraction (XRD) analysis (analytical equipment: Malvern Panalytical (Panalytical Empyrean) Alpha 1) was performed and the crystallinity was calculated using the Scherrer equation of the following formula 1.

[0079] Mathematical formula 1 - Scherrer equation: Lc = 0.89λ / (Bc Cosθ)

[0080] λ = wavelength of anode, 1.540998 (constant)

[0081] Bc=Full Width at Half Maximum (FWHM) (measured value)

[0082] θ = XRD 002 peak position (measured value)

[0083] (3) Measurement of metal impurity content: Inductively coupled plasma spectrometry (Analysis equipment: Inductively Coupled Plasma-Optical Emission Spectrometer)

[0084] (4) Measurement of sulfur content: elemental analysis (analytical equipment: LECO CS-200 analyzer)

[0085] (5) Surface resistance: The post-treated carbon black was dispersed in an isopropyl alcohol (IPA) solvent at a concentration of about 10 weight percent (wt%) to prepare a slurry. The prepared slurry was applied to an aluminum (Al) electrode plate to a thickness of about 50 μm using a doctor blade, and then dried at a temperature of about 100° C. for 1 hour to prepare an electrode. The surface resistance of the prepared electrode was measured using a resistance meter (analysis equipment: Mitsubishi MCP-T610).

[0086] Table 2

[0087]

[0088]

[0089] As shown in Tables 1 and 2, the higher the heat treatment temperature, the more the Lc value indicating crystallinity increases, and the content of metal impurities and sulfur decreases. It can be seen that when nitrogen is used as the atmosphere gas during heat treatment, the effect of reducing the content of metal impurities is greater. It is speculated that this is because, in contrast to the case where argon is a single atomic molecule of Ar, nitrogen is a diatomic molecule of N2. At high temperatures, nitrogen separates into nitrogen ions and combines with metal impurities, thereby vaporizing the metal elements and discharging them. Moreover, compared with the case of using existing powdered carbon black, even when wet-granulated carbon black is used, the physical properties do not change with the heat treatment temperature. In other words, even if the existing wet-granulated carbon black that is not used as a battery material is heat-treated, the physical properties of the same level as those of heat-treated powdered carbon black can be obtained by adjusting the heat treatment conditions.

[0090] Furthermore, it can be confirmed that after the heat-treated carbon black is slurried and coated, the surface resistance value decreases within the heat treatment temperature range of approximately 1200 to 1500°C, but experimental results also show that when the heat treatment temperature exceeds 1500°C, the surface resistance value becomes higher again.

[0091] The electrical conductivity of carbon black used as a conductive material for lithium-ion secondary batteries is the most important physical property, and a low surface resistance value is required. Experiments have confirmed that a heat treatment temperature of 1200 to 1500° C. is appropriate for obtaining conductive carbon black.

[0092] Furthermore, durability is a more demanding property for carbon black used as a catalyst support in fuel cells than electrical conductivity. Therefore, the experimental results confirm that heat treatment temperatures of 2000°C or higher are required for carbon black with a high level of crystallinity, i.e., an Lc of 4 nm or greater.

[0093] Part 2: Lithium-ion secondary battery slurry test

[0094] An experiment was conducted to confirm the relationship between the prepared state of slurry for lithium-ion secondary batteries and the average particle size of pulverized and post-treated carbon black and the prepared state of the slurry.

[0095] - Reference Example 1: Comparative Example 2 was selected as Reference Example 1 for performance comparison with powdered carbon black.

[0096] -Example A: The carbon black heat-treated in Example 2 was pulverized using a jet mill to obtain an average particle size of 10.8 μm, which is referred to as Example A.

[0097] -Comparative Example A: The carbon black heat-treated in Example 2 (not crushed) was used directly as Comparative Example A.

[0098] -Comparative Example B: The carbon black heat-treated in Example 2 was crushed using a high-speed stirring pulverizer, which is a type of high-speed mixer, to a mean particle size of 25.2 μm, which is referred to as Comparative Example B.

[0099] Measuring average particle size

[0100] The average particle size is a value expressed as an average value obtained by analyzing approximately 100 carbon black particles in a scanning electron microscope image observed with a scanning electron microscope. The results are shown in Table 3 below. Figure 14 An example of a method for measuring the average particle size is shown.

[0101] For the reference example 1, embodiment A, comparative example A and comparative example B, scanning electron microscope images were taken using a scanning electron microscope. The results are as follows Figures 2 to 5 shown.

[0102] Evaluation of coating properties of slurries and electrodes for lithium-ion batteries

[0103] ◎ Preparation of slurry: The carbon black of Reference Example 1, Example A, Comparative Example A and Comparative Example B was used to prepare slurry by the following method. The slurry preparation state was evaluated by the naked eye. The results are shown in Table 3 below.

[0104] NCM 523 (cathode active material): carbon black (conductive material): PVDF (binder) were mixed in a ratio of 95:2.5:2.5 (based on weight). NMP was used as the solvent to prepare a slurry solution with a solid content of 50 weight percent. The slurry was dispersed at room temperature for about 30 minutes using a think mixer.

[0105] Electrode Preparation: The slurry was applied to an Al (aluminum) electrode plate using a doctor blade to a thickness of approximately 50-60 μm and then dried at 80°C for approximately 3 hours. The dried electrode was then subjected to a double-roll compression process and dried again in a vacuum atmosphere at approximately 100°C for 12 hours to prepare the positive electrode.

[0106] Table 3

[0107]

[0108] Figure 6 and Figure 7 The figures show the actual coating of the slurries of Example A and Comparative Example A on electrodes.

[0109] The scanning electron microscope images of the electrode cross sections of Example A and Comparative Example A were observed by scanning electron microscope. Figure 8a and Figure 9a As shown in FIG, by using SEM-EDS analysis of SEM images, only the carbon component representing carbon black (only the part represented by green or mint color) was subjected to element distribution characterization (mapping), and the results were as follows: Figure 8b and Figure 9b shown.

[0110] The scanning electron microscope images of the electrode surfaces of Example A and Comparative Example A were observed by scanning electron microscope, as shown in FIG. Figure 10a and Figure 11a As shown in FIG, SEM-EDS analysis of the SEM images was used to characterize the individual element distribution of only the carbon component representing carbon black (part represented by green or mint color), and the results were shown in FIG. Figure 10b and Figure 11b shown.

[0111] Furthermore, scanning electron microscope images and analysis were taken during the electrode preparation evaluation. Figure 2 to Figure 1 As can be seen from the results of Example 1, when fully pulverized carbon black is used as in Example A, the slurry coating property (applicability) is good, and in fact, the dispersibility of carbon black can also be confirmed to be improved in the cross section and surface of the prepared electrode.

[0112] For reference, the high-speed stirring pulverizer used in Comparative Example B is based on the principle of crushing carbon black into powder by physically colliding a stainless steel blade (SUS blade) with the carbon black at high speed. Due to the high-speed collision with the blade, the carbon black may be contaminated with metal impurities such as Fe and Ni. In addition, it is difficult to operate for a long time due to the heat generated during operation. Although the particle size is small, the particle size is larger than that of carbon black in powder form (see Reference Example).

[0113] On the other hand, air jet mills use high-pressure air to pulverize carbon black, making contamination by metallic impurities extremely unlikely. Furthermore, they exhibit the advantage of being able to operate for extended periods of time due to their lack of heat generation. Furthermore, they are suitable for pulverizing powdered carbon black.

[0114] Part 3: Fuel Cell Slurry Test

[0115] An experiment was conducted to confirm the relationship between the prepared state of slurry for fuel cells and the average particle size of pulverized carbon black and post-processing and the prepared state of the slurry.

[0116] - Reference Example 2: Comparative Example 3 was selected as Reference Example 2 for performance comparison with powdered carbon black.

[0117] -Example X: The heat-treated carbon black in Example 4 was pulverized using a jet mill to obtain an average particle size of 13.2 μm, which is referred to as Example A.

[0118] -Comparative Example X: The carbon black heat-treated in Example 4 (not crushed) was used directly as Comparative Example X.

[0119] -Comparative Example Y: The carbon black heat-treated in Example 4 was pulverized using a high-speed stirring pulverizer, which is a type of high-speed mixer, to a mean particle size of 21.2 μm. This was referred to as Comparative Example Y.

[0120] Measuring average particle size

[0121] The average particle size is a value obtained by analyzing approximately 100 carbon black particles in a scanning electron microscope image observed using a scanning electron microscope. The results are shown in Table 4 below.

[0122] Evaluation of the coating properties of anode slurry for fuel cells

[0123] ◎Slurry preparation and coating: The carbon black of Reference Example 2, Example X, Comparative Example X and Comparative Example Y was used as a catalyst carrier to prepare a slurry according to the following method. The slurry preparation state was evaluated by naked eye. The results are shown in Table 4 below.

[0124] Ionomer: carbon black = 50:50 (based on weight), and a solvent of n-butanol: deionized water (DI-water) = 50:50 (based on weight) were used to prepare a slurry solution with a solid content of 10 weight percent. Ultrasonic dispersion was used at room temperature for about 30 minutes.

[0125] ◎ Slurry coating: After coating the slurry on the PTFE film with a thickness of about 10 to 15 μm using a doctor blade, the slurry was dried at 40° C. for about 15 minutes to complete the slurry coating for the fuel cell negative electrode.

[0126] Table 4

[0127]

[0128] The scanning electron microscope images of the slurries of Example X and Comparative Example X coated on the electrodes are observed by scanning electron microscope. Figure 12 and Figure 13 As shown. Figure 12 and Figure 13 As shown, although the coating properties of the slurry cannot be clearly distinguished in the scanning electron microscope image because the slurry is mostly composed of carbon black, the roughness on the surface can be observed with the naked eye. Compared with the comparative example X, the slurry of Example X is significantly smoother, and it can be confirmed that it is better dispersed.

[0129] The embodiments of this specification are described in more detail above, but this specification is not limited to these embodiments, but various modifications can be implemented without departing from the technical ideas of this specification. Therefore, the embodiments disclosed in this specification are not used to limit the technical ideas of the present invention, but to illustrate the present invention, and the scope of the technical ideas of the present invention is not limited by these embodiments. Therefore, no matter from which aspect, the embodiments described above should be interpreted as merely illustrative, not limiting. The scope of protection of this specification and the present invention should be interpreted by the scope of protection claimed in the invention, and all technical ideas within the same scope should be interpreted as included in the scope of rights of this specification and the present invention.

Claims

1. A post-processing method for carbon black, characterized in that: include: Step (a), preparing wet granulated furnace carbon black; Step (b), heat treating the furnace carbon black in a furnace at a temperature above 1200° C.; Step (c), continuously transferring the high-temperature heat-treated furnace carbon black to a pulverizer; as well as Step (d) is to pulverize the furnace carbon black transferred to the pulverizer to obtain carbon black having an average particle size of 20 μm or less.

2. The post-processing method of carbon black according to claim 1, characterized in that The average particle size of the prepared carbon black is less than 15 μm.

3. The post-processing method of carbon black according to claim 1, characterized in that Atmosphere gas is added during the high-temperature heat treatment in step (b).

4. The post-processing method of carbon black according to claim 3, characterized in that The atmosphere gas includes one or more of nitrogen and argon.

5. The post-processing method of carbon black according to claim 1, characterized in that The total content of metal impurities in the prepared carbon black is less than 100 ppm.

6. The post-processing method of carbon black according to claim 1, characterized in that: The heat treatment temperature is 2000-2500°C. The prepared carbon black is a highly crystalline carbon black having an Lc of 4.0 nm or more.

7. The post-processing method of carbon black according to claim 1, characterized in that: The heat treatment temperature is 1000-1500°C. The prepared carbon black is conductive carbon black.

8. The post-processing method of carbon black according to claim 1, characterized in that: The transfer in step (c) is carried out through a fluid medium, The transfer of the furnace carbon black through the fluid medium is performed simultaneously with the separation of the fluid medium from the transferred furnace carbon black.

9. The post-processing method of carbon black according to claim 1, characterized in that The pulverizing process in step (d) can be any one of a high-speed mixer, a ball mill and a jet mill.

10. A carbon black, characterized in that Post-processing according to the post-processing method of any one of claims 1 to 9.

11. A conductive material for lithium-ion secondary batteries, characterized in that: A carbon black post-treated by the post-treatment method of carbon black according to any one of claims 1 to 9.

12. A catalyst carrier for a fuel cell, characterized in that: A carbon black post-treated by the post-treatment method of carbon black according to any one of claims 1 to 9.

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