KR20210094443A - Hollow carbon black assembly having micro-porosity and manufacturing method thereof - Google Patents

Abstract

The present invention relates to a hollow furnace carbon black assembly having micropores and a method for manufacturing the same, wherein the hollow furnace carbon black assembly can be used as a support that can be filled with other materials inside, and can be applied as a material in various fields such as an electrocatalyst support for a secondary battery or a fuel cell, a carbon support, a negative electrode material, and a positive electrode material.

Description

Micro-porous hollow furnace carbon black assembly and manufacturing method thereof

The present invention relates to an assembly including a combination of hollow carbon black having micropores and a method for manufacturing the same, which can be utilized as a carrier capable of filling other materials therein, and a secondary battery Alternatively, the invention can be applied as a material in various fields such as an electrocatalyst carrier for a fuel cell, a carbon support, a negative electrode material, a positive electrode material, and a capacitor electrode active material.

Carbon black is widely used as a black pigment, as a reinforcing agent, as a filler, and the like. Carbon black is produced with different properties by different methods. The most common method is the production method by oxidative pyrolysis of carbon-containing carbon black raw materials. In this case, the carbon black raw material is burned incompletely in the presence of oxygen at a high temperature. Examples of this class of carbon black production method include a furnace black method, a gas black method and a lamp black method. Examples of other methods include an acetylene method, a thermal black method, and a plasma method.

In addition, carbon black is used as a conductive material for manganese batteries, lithium batteries, secondary batteries, etc., due to the characteristic of having high conductivity, and it is known that the more micropores there are in the aggregate of carbon black, the greater the capacity is. In fuel cells, it is used as a catalyst carrier for the catalyst layer, and studies are being conducted to control the specific surface area of carbon black to reduce the amount of expensive platinum catalyst added and increase the active area. For example, various attempts have been made to form pores by chemically activating the surface of carbon black, or to increase energy storage by maintaining conductivity by introducing a mixed secondary structure between carbon blacks.

Korean Patent Publication No. 10-2014-0087393 (published on July 9, 2014)

As a result of repeated research for controlling the specific surface area of carbon black, the present inventors found that hollow carbon black having a significantly increased micropore volume and increased specific surface area of the furnace carbon black among carbon blacks could be manufactured. , In addition, in a specific manufacturing process, it was found that a tunnel is formed while a plurality of hollow carbon blacks are combined and integrated, that is, an empty space inside the bonded carbon black, that is, internal pores are connected, thereby completing the present invention.

As described above, an object of the present invention is to provide a microporous hollow furnace carbon black assembly including a microporous hollow furnace carbon black binder having a significantly increased specific surface area and increased micropore volume compared to the raw material carbon black, and a method for manufacturing the same.

The present invention for solving the above problems relates to a micro-porous hollow furnace carbon black assembly, comprising a single or a plurality of integrated bodies in which a plurality of micro-porous hollow carbon blacks are bonded, and the plurality of micro-porous pores Each of the hollow furnace carbon blacks has a hollow structure and has a plurality of micro-sized pores, and the binder is a hollow furnace in which all or some of the internal pores in the carbon black of the combined plurality of micro-porous hollow furnace carbon blacks are connected to each other. An internal tunnel may be formed in the carbon black binder.

As a preferred embodiment of the present invention, the microporous hollow furnace carbon black assembly of the present invention may have a mesopore volume satisfying Equation 1 below.

[Equation 1]

3.0 ≤ B/A ≤ 8.0

In Equation 1, A is the mesopore volume of the furnace carbon black before performing the gas phase oxidation reaction, and B is the mesopore volume of the binder formed by performing the gas phase oxidation reaction.

As a preferred embodiment of the present invention, the binder may have a BET specific surface area of 400 to 1,000 m ² /g.

As a preferred embodiment of the present invention, the binder may have a total pore volume of 0.550 to 1.500 cm ³ /g.

As a preferred embodiment of the present invention, the average micropore diameter of the microporous hollow carbon black constituting the binder may be 4.0 to 8.0 nm.

Another object of the present invention relates to a method for producing the aforementioned microporous hollow carbon black, comprising: a first step of preparing the furnace carbon black; a second step of performing a gas phase oxidation reaction of the furnace carbon black using an oxidizing gas; and three steps of separating and obtaining a binder to which a plurality of hollow carbon blacks are bonded from the gas phase oxidation reactant;

As a preferred embodiment of the present invention, the gas phase oxidation reaction of step 2 is performed in an oxidation chamber, and while supplying an oxidizing gas in the oxidation chamber at 900 to 1,300° C., it may be performed for 80 to 150 minutes.

As a preferred embodiment of the present invention, the oxidizing gas of step ₂ may contain 99.000 ~ 99.999% by volume of CO 2 .

As a preferred embodiment of the present invention, the gas phase oxidation reaction of the second step may be performed while supplying the oxidizing gas into the oxidation chamber at a rate of 150 to 300 mL/min.

As a preferred embodiment of the present invention, each of the plurality of hollow furnace carbon blacks constituting the three-stage assembly has a hollow structure and may have a plurality of micro-sized pores.

As a preferred embodiment of the present invention, in the binder, a plurality of microporous hollow carbon blacks are combined and integrated, and all or some of the combined plurality of microporous hollow furnace carbon blacks have internal pores in the carbon black. They may be connected to form an internal tunnel in the hollow furnace carbon black assembly.

As a preferred embodiment of the present invention, the assembly may include one or more of the inner tunnel.

As a preferred embodiment of the present invention, the mesopore volume of the three-stage assembly may satisfy the following equation.

[Equation 1]

3.0 ≤ B/A ≤ 8.0

In Equation 1, A is the mesopore volume of the furnace carbon black before performing the gas phase oxidation reaction, and B is the mesopore volume of the binder formed by performing the gas phase oxidation reaction.

In addition, another object of the present invention relates to an application using the microporous hollow carbon black described above, comprising an electrocatalyst carrier for a fuel cell comprising the microporous hollow carbon black, and the microporous hollow carbon black To provide a carbon support for a secondary battery, a capacitor electrode active material, and the like.

The carbon black assembly produced by the production method of the present invention increases the mesopore volume by at least 3 times and as much as 8.0 times that of the furnace carbon black before the gas phase oxidation treatment, and as a result, microporous pores having a high specific surface area and high mesovolume of hollow furnace carbon black. And, as shown schematically in FIG. 1 , each of the carbon blacks constituting the binder has a hollow shape, and since they are combined to form a larger empty space (tunnel), various materials can be supported and electrical properties It is also excellent, and can be used as a material in a wide variety of fields.

1 is a schematic diagram for explaining the structural difference between the structure of porous carbon black before gas phase oxidation reaction, microporous hollow carbon black formed after acid oxidation reaction, and the microporous hollow furnace carbon black assembly (assembly).
2 is a schematic diagram of an oxidation chamber used for a gas phase oxidation reaction in the present invention.
3A and 3D are TEM measurement photographs of microporous hollow furnace carbon black prepared by performing gas phase oxidation reaction at 1,000° C. for different reaction times.

Hereinafter, the present invention will be described in more detail through a method for manufacturing the microporous hollow furnace carbon black assembly of the present invention.

Step 1 of preparing the furnace carbon black of the present invention; a second step of performing a gas phase oxidation reaction of the furnace carbon black _{using CO 2 as an oxidizing gas;} and a third step of separating the binder to which a plurality of hollow carbon blacks are bonded from the vapor phase oxidation reactant; thereby, a microporous hollow furnace carbon black assembly may be manufactured.

As the furnace carbon black in step 1, commercially available furnace carbon black may be used, and preferably at least one selected from the brand name Super-p and the brand name C-NERGY. Furnace carbon black containing may be used.

The vapor-phase oxidation reaction of the second step may be performed in the oxidation chamber schematically shown in FIG. 2, and after furnace carbon black is introduced into the oxidation chamber, the vapor-phase oxidation reaction may be performed while supplying an oxidizing gas into the oxidation chamber.

The gas phase oxidation reaction may be performed for 80 minutes to 150 minutes under 900 to 1300° C. while supplying an oxidizing gas in the oxidation chamber, preferably for 80 minutes to 130 minutes under 950 to 1250° C., more preferably It can be carried out for 90 minutes to 120 minutes under 980 ~ 1200 ℃. If the gas phase oxidation reaction temperature is less than 900° C. or the gas phase oxidation reaction time is less than 80 minutes, there may be a problem in that the specific surface area and mesopore volume of the furnace carbon black binder obtained by the gas phase oxidation reaction are low, There can be a problem with low yield for pore hollow carbon black. In addition, when the gas phase oxidation reaction temperature exceeds 1300° C. or the gas phase oxidation reaction time exceeds 150 minutes, physical properties such as specific surface area and micropore volume of carbon black no longer increase, and pores (voids) Because the retaining wall becomes thinner, the pore shape collapses, and the mechanical strength of carbon black becomes too low and is easily broken, there may be a problem in that the yield of the microporous hollow carbon black assembly in the form of a binder is greatly lowered. good to do

As the oxidizing gas, CO ₂ is used, preferably 99.000 to 99.999 vol%, preferably 99.500 to 99.999 vol%, more preferably 99.800 to 99.999 vol%, CO ₂ is preferably used.

And, while supplying the oxidizing gas into the oxidation chamber at a flow rate (or flow rate) of 150 to 300 mL/min, preferably 150 to 250 mL/min, more preferably 180 to 250 mL/min, the gas phase oxidation reaction may be performed. can At this time, if the flow rate of the oxidizing gas is less than 150 mL/min, the yield of the microporous hollow furnace carbon black assembly is less than 50%, so there may be a problem that the mesopore volume is low, and the flow rate of the oxidizing gas is 300 mL/min If the number of minutes is exceeded, the wall holding the pores (pores) becomes thin and the pore shape collapses, and the mechanical strength of carbon black is too low and is easily broken. there may be

In addition, the yield of the microporous hollow furnace carbon black assembly prepared by the above method may be 58% to 84%, preferably 60% to 82%, and more preferably 70% to 82%.

The gas phase oxidation reactant of the second step includes a plurality of binders to which a plurality of microporous hollow carbon blacks described above are bonded, and a plurality of unbonded microporous hollow carbon blacks.

Step 3 is a process of separating the binder from the gas phase oxidation reactant of step 2, and it can be performed through a general physical separation method used in the art, and for example, it can be separated through sieve separation, In order to maximize the yield of the binder when performing the separation method, it is preferable to perform the separation method to minimize breakage of the binder.

The micro-porous hollow furnace carbon black assembly of the present invention manufactured by this method includes: micro-porous hollow carbon black; and a binder in which a plurality of the microporous hollow furnace carbon black are combined to form an integrated body.

Each of the plurality of micro-porous hollow furnace carbon blacks has a hollow structure and has a plurality of micro-sized pores, and the binder has internal pores in all or part of the combined plurality of micro-porous hollow furnace carbon blacks. These may be connected to each other to form an internal tunnel in the hollow furnace carbon black assembly (refer to the schematic diagram of FIG. 1 ).

The binder may have a mesopore volume satisfying Equation 1 below.

[Equation 1]

3.0 ≤ B/A ≤ 5.5, preferably 3.2 ≤ B/A ≤ 5.2, more preferably 3.5 ≤ B/A ≤ 5.0

In Equation 1, A is the mesopore volume of the furnace carbon black before performing the gas phase oxidation reaction, and B is the mesopore volume of the binder formed by performing the gas phase oxidation reaction.

In addition, the microporous hollow furnace carbon black assembly of the present invention may include a single or a plurality of the ^{binder, wherein the binder has a BET specific surface area of 400 to 1,200 m 2} /g, preferably a BET specific surface area of 450 to 1,000 m ² /g, more preferably 540 to 900 m ² /g, even more preferably 570 to 830 m ² /g.

And, each of the micro-porous hollow furnace carbon black constituting the assembly; Or, microporous hollow carbon black other than the binder that may be included in the assembly; the average particle diameter of the micropores may be 4.0 to 8.0 nm, preferably 4.0 to 6.5 nm, more preferably 4.0 to 6.0 nm can

These, of the present invention Microporous hollow furnace carbon black can support various materials and has excellent electrical properties, so it can be used as a material in a wide variety of fields, for example, an electrocatalyst support for fuel cells, carbon support for secondary batteries, etc. .

Hereinafter, the present invention will be described in more detail based on examples. However, the scope of the present invention should not be construed as being limited by the following examples.

[Example]

Example 1: Preparation of microporous hollow furnace carbon black assembly according to reaction time

Furnace carbon black (trade name: Super-P, manufacturer: IMERYS) was prepared as a raw material. The basic physical properties of the prepared furnace carbon black are shown in Table 1 below.

BET
non-representative (m ² /g) mezzo
Pore volume (cm ³ /g) total pore volume
(cm ³ /g) average pore size 61.4 0.155 0.165 10.8 nm

Next, after preheating the horizontal tubular furnace (oxidation chamber) shown in FIG. 2 to 1000° C., the raw material is charged into the reaction tube of the oxidation chamber using a quartz boat, and then fixed at 1000° C. A gas phase oxidation reaction was performed. _{An oxidizing gas containing CO 2} at a concentration of 99.950% by volume as a reactive substance was used, and the flow rate of the oxidizing gas was maintained at 150 ml/min using a ball flow meter. And, the reaction time is shown in Table 2 below.

Next, a plurality of micro-hollow furnace carbon blacks are combined from the vapor phase oxidation reaction product including the micro-hollow furnace carbon black and their binders to activate and separate an integrated binder (aggregate) to prepare a micro-porous hollow furnace carbon black assembly. obtained.

In addition, transmission electron microscopy (TEM, magnification: 800,000 times) measurement photos of the formed Daehan microporous hollow furnace carbon black at the reaction time of 0 min, 55 min, 98 min and 115 min are shown in FIG. 3a.

In addition, when the reaction time was 98 minutes, the obtained microporous hollow furnace carbon black was measured at different magnifications and is shown in FIG. 3B .

In addition, at the reaction times of 98 minutes, 115 minutes, and 148 minutes, SEM measurements of the obtained aggregate of the microporous hollow furnace carbon black are shown in FIG. 3C .

Referring to FIG. 3a, in the case of furnace carbon black that is not subjected to vapor phase oxidation treatment, no pores are observed inside and no pores are developed inside, so it can be seen that the ^{BET specific surface area is very small as 61.4 m 2 /g.} .

Referring to FIG. 3A , in the case of furnace carbon black subjected to gas phase oxidation treatment for 55 minutes, 98 minutes, and 115 minutes, it was observed that the crystallites inside were clouded and micropores were formed. Compared to the raw material furnace carbon black, mesopores were observed. It was confirmed that the volume increased by 1.5 to 8.1 times.

In addition, referring to FIG. 3B , it can be seen that a plurality of microporous hollow furnace carbon blacks are combined and integrated to form a combined aggregate, and the internal spaces of the combined carbon black are connected to form a tunnel inside the aggregate.

Referring to FIG. 3C , it can be seen that the length of the binder (aggregate, assembly) tends to increase as the reaction time of the gas phase oxidation treatment increases.

In addition, the yield (%), BET specific surface area (m ² /g), and mesopore volume (cm ³ /g) of the microporous hollow furnace carbon black assembly prepared and obtained according to each reaction time are shown in the table below. 2 is shown.

temperature
(℃) reaction
time
(minute) assembly
transference number
(%) BET
non-representative
(m ² /g) mesophore
volume
(cm ³ /g) mesopore volume ratio
(B/A) 1,000 0 0 61.4 0.155 One 55 20 340.6 0.236 1.52 85 60 450.1 0.531 3.43 98 75 590.5 0.589 3.80 115 80 788.1 0.706 4.55 148 45 1138.1 1.229 7.93 170 30 1218.3 1.257 8.11 A of the mesopore volume ratio is the mesopore volume of the furnace carbon black (=0.155 cm ³ /g) before performing the gas phase oxidation reaction, and B is the mesopore volume of the binder formed by performing the gas phase oxidation reaction.

Looking at Table 2 above, as the gas phase oxidation reaction time increased, the BET specific surface area, mesopore volume, and total pore volume tended to increase. However, if the gas phase oxidation reaction is performed for too long, the furnace carbon black assembly structure collapses It was confirmed that there is a problem in that the yield is lowered.

Therefore, it was confirmed that the appropriate gas phase oxidation reaction time for securing the yield is about 80 minutes to 150 minutes, preferably 80 minutes to 130 minutes, and more preferably about 90 minutes to 120 minutes.

Example 2: Preparation of microporous hollow furnace carbon black assembly according to reaction temperature

In the same manner as in Example 1, the furnace carbon black (raw material) was subjected to vapor phase oxidation, but the oxidation treatment temperature was changed as shown in Table 3 below to prepare microporous hollow furnace carbon black assemblies, respectively, and the prepared furnace carbon black assemblies was measured.

temperature
(℃) reaction
time
(minute) assembly
transference number
(%) BET
non-representative
(m ² /g) mesophore
volume
(cm ³ /g) mesopore volume ratio
(B/A) 850 98 55 340.6 0.481 3.10 950 60 510.5 0.521 3.36 1000 75 590.5 0.589 3.80 1150 78 688.1 0.639 4.12 1250 80 720.5 0.699 4.51 1350 20 842.3 0.249 1.61 A of the mesopore volume ratio is the mesopore volume of the furnace carbon black (=0.155 cm ³ /g) before performing the gas phase oxidation reaction, and B is the mesopore volume of the binder formed by performing the gas phase oxidation reaction.

Looking at Table 3, it can be seen that the yield increases as the reaction temperature increases, and the BET specific surface area and mesopore volume tend to increase. In comparison, there is a problem in that the yield of the microporous hollow furnace carbon black assembly is sharply reduced, which is that the burn-off carbon black increases, and the skin of the carbon black constituting the assembly is too thin to break and break away from the assembly. It is believed that this is because the amount of black increases.

And, when the reaction temperature is less than 950 °C at 900 °C, the yield of the binder is too low and the mesopore volume has a problem of having low physical properties.

Example 3: Preparation of microporous hollow furnace carbon black assembly according to oxidizing gas flow rate

In the same manner as in Example 1, the furnace carbon black (raw material) was subjected to vapor phase oxidation, but the flow rate of the oxidizing gas was changed as shown in Table 4 below to prepare microporous hollow furnace carbon black assemblies, and their physical properties were measured.

CO ₂ flow
(ml/min) reaction time/
reaction temperature assembly
transference number
(%) BET
non-representative
(m ² /g) mesophore
volume
(cm ³ /g) mesopore volume ratio
(B/A) 120 98 minutes /
1000℃ 41 392.6 0.298 1.92 150 75 590.5 0.589 3.80 200 81 744.3 0.672 4.33 250 82 871.8 0.903 5.82 300 82 875.5 0.917 5.92 330 78 792.7 0.774 4.99

Looking at the experimental results in Table 4, when the CO ₂ flow rate is less than 150 ml/min, 120 ml/min, the yield day is as low as less than 50%, and the mesopore volume ratio is also less than 3.00, showing poor results. However, when the CO ₂ flow rate was 150 ml/min to 300 ml/min, it showed an excellent yield of 70% or more and a result having a high mesopore volume ratio. However, when the CO ₂ flow rate is 330 ml/min, which exceeds 300 ml/min, the yield is rather low, and the mesopore volume ratio and specific surface area are decreased, which is because oxidation proceeds too much and rather constitutes an assembly. It is considered that this is because the skin of the carbon black is too thin to break and the amount of carbon black separated from the binder increases.

Through the above Examples and Experimental Examples, a microporous furnace carbon black assembly having a tunnel formed therein with a very high mesopore volume and BET specific surface area than the raw material can be manufactured with high yield through the manufacturing method of the present invention. could confirm that there was The microporous hollow furnace carbon black assembly of the present invention can support various materials and has excellent electrical properties, so it is expected that it can be used as a material in a wide variety of fields.

Claims (10)

Step 1 of preparing furnace carbon black;
a second step of performing a gas phase oxidation reaction of the furnace carbon black _{using CO 2 as an oxidizing gas;} and
3 step of separating and obtaining a binder in which a plurality of hollow furnace carbon blacks are bonded from the gaseous oxidation reaction product;
A method of manufacturing a microporous hollow furnace carbon black assembly, wherein each of the plurality of hollow furnace carbon blacks has a hollow structure and has a plurality of micro-sized pores.
According to claim 1, wherein the binder is integrated with a plurality of micro-porous hollow furnace carbon black,
Of the microporous hollow furnace carbon black assembly, characterized in that all or part of the internal pores in the carbon black of a plurality of combined microporous hollow furnace carbon black are connected to each other to form an internal tunnel in the hollow furnace carbon black assembly. manufacturing method.
The method of claim 2, wherein the assembly includes at least one inner tunnel.
According to claim 1, wherein the gas phase oxidation reaction is carried out in an oxidation chamber,
A method of manufacturing a microporous hollow furnace carbon black assembly, characterized in that it is carried out for 80 to 150 minutes while supplying the oxidizing gas under 900 to 1,300° C.
According to claim 1, wherein the oxidizing gas comprises 99.000 ~ 99.999% by volume of CO ₂ ,
The gas phase oxidation reaction is a method of manufacturing a microporous hollow furnace carbon black assembly, characterized in that it is performed while supplying an oxidizing gas at a rate of 150 to 300 mL/min.
The method of claim 1, wherein the mesopore volume of the three-step assembly satisfies the following equation;
[Equation 1]
3.0 ≤ B/A ≤ 8.0
In Equation 1, A is the mesopore volume of the furnace carbon black before performing the gas phase oxidation reaction, and B is the mesopore volume of the binder formed by performing the gas phase oxidation reaction.
A plurality of microporous hollow carbon blacks are combined to include a single or a plurality of integrated bodies,
Each of the plurality of micro-porous hollow furnace carbon black has a hollow structure and has a plurality of micro-sized pores,
The binder is a microporous hollow furnace carbon, characterized in that all or part of the internal pores in the carbon black of a plurality of combined microporous hollow furnace carbon black are connected to each other to form an internal tunnel in the hollow furnace carbon black binder black assembly.
8. The method of claim 7,
Microporous hollow furnace carbon black assembly, characterized in that it has a mesopore volume satisfying Equation 1 below;
[Equation 1]
3.0 ≤ B/A ≤ 8.0
In Equation 1, A is the mesopore volume of the furnace carbon black before performing the gas phase oxidation reaction, and B is the mesopore volume of the binder formed by performing the gas phase oxidation reaction.
An electrocatalyst carrier for a fuel cell comprising the microporous hollow furnace carbon black assembly of claim 7 or 8.
A carbon support for a secondary battery comprising the microporous hollow furnace carbon black assembly of claim 7 or 8.

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