KR102539683B1 - Preparation method for activated carbon with multi pore structure and activated carbon with multi pore structure prepared by the same - Google Patents

Abstract

An object of the present invention is to provide a method for preparing activated carbon having a multi-pore structure and an activated carbon having a multi-pore structure prepared thereby. To this end, the present invention comprises the steps of synthesizing pitch by heating a carbon source at 350 to 500 ° C; And activating the synthesized pitch; provides a method for producing activated carbon having a multi-pore structure, including the activated carbon produced thereby, an electrode material including the same, a method for manufacturing the same, and an electric double layer capacitor including the same. do. According to the present invention, it is possible to manufacture activated carbon having a multi-pore structure in which micropores are formed on the surface of macropores, thereby increasing the specific surface area of the activated carbon, and when used as an electrode material, the specific surface area is reduced. Not only does the specific capacitance increase as it is wide, but ions are efficiently transported to the micropores through the macropores, which has the advantage of having excellent electrical properties.

Description

Method for producing activated carbon having a multi-pore structure and activated carbon having a multi-pore structure produced thereby

The present invention relates to a method for preparing activated carbon having a multi-pore structure and an activated carbon having a multi-pore structure prepared thereby.

In addition, the present invention relates to an electrode material containing the activated carbon and a manufacturing method thereof.

Electric double layer capacitor (EDLC) is a material for energy storage devices and has higher power density and lifespan characteristics than secondary batteries. . Conductive polymers, metal oxides, and carbon materials are used as EDLC electrode materials. In particular, porous activated carbon-based carbon materials with a large specific surface area are most widely used to increase the capacity of EDLC.

Activated carbon for EDLC is manufactured through an activation process of cellulosic biomass such as coconut husks and rice hulls or petroleum/coal-based coke. In the case of EDLC electrodes using biomass, a high specific surface area can be imparted through activation, making it possible to manufacture electrodes with high capacities, but materials with relatively low crystal properties and low conductivity are manufactured. In the case of coke-based, the conductivity is high due to high crystalline properties, but the structure is solid and is not easily activated, so there is a limit to imparting a high specific surface area.

Pitch is a material obtained through polymerization of organic compounds including petroleum and coal-based residues at 300 ~ 500 ° C. It is a soft material and is an intermediate carbon material in which crystals are formed during the heat treatment process. In addition, as a thermoplastic material having a wide range of molecular weight ranges, it has the advantage of being easy to control the pore structure by utilizing these characteristics. Therefore, by appropriately adjusting the molecular weight characteristics of the pitch, it is possible to manufacture a highly conductive electrode material for EDLC with a high specific surface area.

Currently, in the case of activated carbon (MSP20, RP/YP series), which is widely used as an EDLC material, it is manufactured through precursors such as coconut shells, wood, and polymers. In the case of such a raw material, there is an advantage in that the supply and demand of the material is easy, but it has a limitation in that the pore characteristics of the activated carbon can be controlled only through the activation process parameters. On the other hand, unlike the above materials, in the case of pitch, it is possible to sufficiently control the basic physical properties of the pitch, such as molecular weight, so that the pore characteristics can be controlled by controlling the physical properties of the precursor. Therefore, if the pitch is used, it is possible to control the pore characteristics of activated carbon through more various methods than in the prior art.

For example, Korean Patent Registration No. 10-0650618 describes a method for producing activated carbon having a high specific surface area for capacitor electrodes. a THF soluble content removal step to control; Mixing by adding sodium hydroxide (NaOH) or potassium hydroxide (KOH) as an activator to the carbon raw material loaded into the reactor either alone or in a mixed form so that the weight ratio of the carbon raw material and the activator is 1:2 to 1:6. step; an absorption step of maintaining the temperature inside the reactor at 400 to 500° C. so that the activator can be completely absorbed into the carbon raw material; A method for producing activated carbon having a high specific surface area for a capacitor electrode is disclosed, comprising an activation step of inducing an activation reaction by raising the temperature inside the reactor to 600 to 900° C. after the absorption step. However, the above document does not describe treatment of a carbon source in order to control the porosity of activated carbon in order to increase the capacity of an electrode.

Next, Korean Patent Registration No. 10-1525534 describes activated carbon activated with an alkali-based activator and an electrode for a supercapacitor using the activated carbon. Coal tar pitch having a weight ratio of and an alkali-based activator of KOH, NaOH or LiOH was heated at 05 to 20 ° C / min and maintained at 900 to 1300 ° C for 30 minutes to surface-modified, with a specific surface area of 1,000 to 3,800 m / g , by mixing activated carbon powder having a micropore amount of 03 to 17 cm3 / g with a binder solution

A thin activated carbon plate was prepared and prepared by pressing the prepared activated carbon thin plate with a porous nickel foam having a thickness of 01 mm, using 80% by weight of activated carbon powder as an active material, 10% by weight of PVDF as a binder, and 10% by weight of conductive carbon black as a conductive material. %, and an electrode for a supercapacitor is disclosed, characterized in that a 6M KOH aqueous solution is used as an electrolyte. However, since coal tar pitch itself is used as a carbon source in the above document, information on controlling the pore structure through a synthesis process is not disclosed.

In addition, Korean Patent Registration No. 10-1580892 describes a method for manufacturing a pitch-based carbon/manganese oxide composite for supercapacitors. Specifically, (1) a pretreatment in which pitch-based carbon is mixed with HCl and stirred for 2 to 3 hours step; (2) mixing 1:4 KOH with the pitch-based carbon pretreated in step (1) and activating it at 800 to 900 ° C. for 1 hour; and (3) mixing the pitch-based carbon activated by step (2) with an aqueous solution of KMnO4 and stirring for 1 hour to introduce Mn7+; (4) adding Mn(Ac)2·4H2O to the pitch-based carbon into which Mn7+ was introduced in step (3) and stirring at 100 °C for 8 hours to generate manganese oxide on the surface; and (5) recovering pitch-based carbon from which manganese oxide is generated in step (4) with a pressure-reducing filter and drying it at 80 ° C. for 24 hours. has been initiated. However, in the above document, only pitch-based carbon is used as a carbon source, and there is no description of adjusting the porosity of activated carbon by controlling the temperature in the process of synthesizing pitch.

Accordingly, the inventors of the present invention completed the present invention by confirming that the porosity of the finally produced activated carbon can be controlled by controlling the molecular weight by adjusting the synthesis temperature in synthesizing pitch using residue oil as a carbon source.

An object of the present invention is to provide a method for preparing activated carbon having a multi-pore structure and an activated carbon having a multi-pore structure prepared thereby.

Another object of the present invention is to provide an electrode material containing the activated carbon and a manufacturing method thereof.

To this end, the present invention

synthesizing pitch by heating a carbon source at 350 to 500 °C; and

activating the synthesized pitch;

It provides a method for producing activated carbon having a multi-pore structure comprising a.

In addition, the present invention

Provided is an activated carbon having a multi-pore structure produced by the above method and characterized in that micropores are formed on the surface of the macropores.

Furthermore, the present invention

synthesizing pitch by heating a carbon source at 350 to 500 °C;

activating the synthesized pitch; and

carbonizing the activated pitch;

It provides a method for manufacturing an electrode material comprising a.

Furthermore, the present invention

Provided is an electrode material produced by the above method and characterized in that it has a multi-pore structure in which micropores are formed on the surface of macropores.

Furthermore, the present invention

It provides an electric double layer capacitor comprising the above electrode material.

According to the present invention, it is possible to manufacture activated carbon having a multi-pore structure in which micropores are formed on the surface of macropores, thereby increasing the specific surface area of the activated carbon, and when used as an electrode material, the specific surface area is reduced. Not only does the specific capacitance increase as it is wide, but ions are efficiently transported to the micropores through the macropores, which has the advantage of having excellent electrical properties.

1 is a SEM picture of activated carbon according to an embodiment of the present invention, and
2 is a molecular weight distribution graph of activated carbon according to an embodiment of the present invention.

The present invention provides a method for producing activated carbon having a multi-pore structure.

In addition, the present invention provides activated carbon having a multi-pore structure, which is produced by the above method and is characterized in that micropores are formed on the surface of macropores.

Furthermore, the present invention provides a method for manufacturing an electrode material.

Furthermore, the present invention provides an electrode material produced by the above method and characterized by having a multi-pore structure in which micropores are formed on the surface of macropores.

Furthermore, the present invention provides an electric double layer capacitor comprising the electrode material.

In the specification of the present invention, "multiple pore structure" means a structure in which a pore structure is formed again on the surface of the pore structure.

In the present invention, "macropore" or "cavity" means a pore structure with a pore size of 0.1 μm to 5 μm, and "micropore" means a pore structure with a pore size of 2 nm or less.

Hereinafter, the present invention will be described in detail for each technology.

the present invention

synthesizing pitch by heating a carbon source at 350 to 500 °C; and

activating the synthesized pitch;

It provides a method for producing activated carbon having a multi-pore structure comprising a.

Hereinafter, the manufacturing method of the present invention will be described in detail for each step.

The manufacturing method according to the present invention includes the step of synthesizing pitch by heating a carbon source at 350 to 500 °C. Pitch is a material obtained by polymerizing carbon sources such as petroleum and coal-based organic compounds at a temperature of 300 to 500 ° C., is a soft material, and is an intermediate carbon material in which crystals are formed during heat treatment.

At this time, the temperature at which the carbon source is heated to synthesize the pitch is 350 to 500 ° C. By controlling the heating temperature for pitch synthesis, the molecular weight of the pitch to be produced can be controlled. At this time, the heating temperature must be adjusted to 350 to 500 ° C. to produce a pitch containing a large amount of components with relatively low molecular weight, and in the subsequent activation process, the components with relatively low molecular weight are vaporized first, forming a large to form pores. If the heating temperature is less than 350 ℃, there is a problem that sufficient low boiling point removal and polymerization do not occur, making it impossible to manufacture pitch that is solid at room temperature. Since many of them are included, there is a problem in that macropores are not sufficiently formed during the subsequent activation process.

The manufacturing method according to the present invention includes synthesizing the pitch and then activating the synthesized pitch. At this time, activating the pitch means forming a pore structure in the pitch, and in the case of the present invention, by adjusting the molecular weight in the process of synthesizing the pitch, in the step of activating the pitch, macropores and micropores on the surface of the macropores This is formed to form a multi-pore structure.

Such a multi-pore structure having macropores and micropores formed on the surface not only increases the specific surface area of the activated carbon, but also allows ions to easily flow into the micropores through the macropores when used as an electrode material. As a result, the electrical characteristics are improved.

In the production method of the present invention, the carbon source may be various organic compounds that can be synthesized into pitch, and for example, petroleum-based residue or coal-based coal tar is preferable. For example, cellulose-based biomass may be considered as the carbon source, but when producing activated carbon through this, a wide specific surface area can be guaranteed, but there is a problem in that conductivity is lowered due to low crystal characteristics. In the manufacturing method of the present invention, it is preferable to use petroleum-based residue oil or coal-based coal tar, through which activated carbon with high conductivity can be produced, and the problem that is not easily activated is the temperature range control and activation step in the pitch synthesis process. can be solved through

In the manufacturing method of the present invention, the step of synthesizing the pitch is preferably performed at a temperature range of 370 to 420 ° C. When the synthesis temperature is less than 370 ℃, there is a problem that the thermal stability of the pitch is low, which can cause the collapse of the pore structure during the activation process. There is a problem that doesn't work.

In addition, the temperature range is more preferably 380 to 400 ℃ considering the specific surface area of the activated carbon to be produced.

In addition, the step of synthesizing the pitch is preferably performed for 1 to 20 hours. If the synthesis time is less than 1 hour, there is a problem in that pitch is not sufficiently synthesized from the carbon source, and if it exceeds 20 hours, the coking reaction due to polymerization proceeds, which is disadvantageous in forming pores on the surface.

On the other hand, in the step of synthesizing pitch in the production method of the present invention, the molecular weight of the components included in the final pitch is adjusted by adjusting the temperature range during synthesis. It is preferably carried out at 20 to 30% by weight relative to the total pitch weight. As described above, since components having a relatively low molecular weight are sufficiently included in the pitch, macropores are sufficiently formed before formation of micropores in a subsequent activation process, and activated carbon having a desired multi-pore structure can be prepared.

The step of activating the synthesized pitch in the production method of the present invention is preferably performed by a chemical method or a physical method. Specifically, the chemical method may be understood as a method of forming a pore structure by mixing synthesized pitch and a chemical substance, and the physical method may be understood as a method of forming a pore structure by applying physical force to the synthesized pitch.

Specifically, the chemical method may be performed by mixing the synthesized pitch with a basic solution, and the basic solution is absorbed into the pitch to form a pore structure in the pitch.

In this case, the basic solution is preferably one or more solutions selected from the group consisting of a KOH solution, a NaOH solution, and a H ₃ PO ₄ solution.

In addition, the physical method may be performed by applying steam or carbon dioxide gas to the synthesized pitch, and a pore structure may be formed in the synthesized pitch through this process.

More specifically, in the step of activating the synthesized pitch in the production method of the present invention, the synthesized pitch and KOH are mixed, but the ratio is preferably in the range of 1: 1 to 1: 4 in terms of weight ratio. If the KOH content is less than the above range, there is a problem that the synthesized pitch is not sufficiently activated, and if the KOH content exceeds the above range, the pore structure may collapse and the conductivity may deteriorate. .

The step of activating the pitch synthesized in the manufacturing method of the present invention is preferably performed while raising the temperature from room temperature to 900 ℃. In the process of activating the pitch by performing various methods such as chemical or physical on the synthesized pitch, that is, forming a pore structure in the pitch, the pore structure is formed while raising the temperature from room temperature to a high temperature of 900 ° C. In the temperature range of 500 ° C, macropores are formed while the relatively low molecular weight components contained in the pitch synthesized in the step of synthesizing the pitch are removed, and then micropores are formed on the surface of the macropores in the process of raising the temperature to 900 ° C. formed, and finally activated carbon having a multi-pore structure can be prepared. If, even if the temperature of the activation step exceeds 900 ℃, there is no effect, there is a problem that the process cost increases.

The activation, for example, transfers the mixture of the synthesized pitch and KOH for activation to an alumina boat, raises the temperature to 850 ℃ at a heating rate of 5 ℃ per minute in a carbonization furnace, and heat-treats at that temperature for 1 hour method can be performed.

In addition, the present invention provides activated carbon having a multi-pore structure, which is prepared by the above method and includes macropores and micropores formed on the surface thereof.

In the present invention, macropores refer to pores having a size of 0.1 μm to 5 μm, and micropores refer to pores having a size of 2 nm or less. The activated carbon having a multi-pore structure according to the present invention is prepared by the above method, so that macropores are first formed by materials having a relatively low molecular weight in the activation process, and the surface of the macropores in the process of further raising the temperature. Micropores are formed in the micropores, and finally, activated carbon having a multi-pore structure is formed.

The activated carbon having a multi-pore structure according to the present invention includes macropores and micropores on its surface, thereby increasing the specific surface area of the activated carbon, and it is easy for external substances to access the micropores through the macropores. There are advantages. Therefore, when the activated carbon is used as an electrode of a capacitor, the specific capacitance increases as the specific surface area increases, and the ions can easily access the micropores through the macropores, resulting in improved electrical properties. There is an advantage to being

In addition, the present invention

synthesizing pitch by heating a carbon source at 350 to 500 °C; and

activating the synthesized pitch;

It provides a method for manufacturing an electrode material comprising a.

Hereinafter, the manufacturing method of the electrode material of the present invention will be described in detail for each step.

The manufacturing method according to the present invention includes the step of synthesizing pitch by heating a carbon source at 350 to 500 °C. Pitch is a material obtained by polymerizing carbon sources such as petroleum and coal-based organic compounds at a temperature of 300 to 500 ° C., is a soft material, and is an intermediate carbon material in which crystals are formed during heat treatment.

At this time, the temperature at which the carbon source is heated to synthesize the pitch is 350 to 500 ° C. By controlling the heating temperature for pitch synthesis, the molecular weight of the pitch to be produced can be controlled. At this time, the heating temperature must be adjusted to 350 to 500 ° C. to produce a pitch containing a large amount of components with relatively low molecular weight, and in the subsequent activation process, the components with relatively low molecular weight are vaporized first, forming a large to form pores. If the heating temperature is less than 350 ℃, there is a problem that sufficient low boiling point removal and polymerization do not occur, making it impossible to manufacture pitch that is solid at room temperature. Since many of them are included, there is a problem in that macropores are not sufficiently formed during the subsequent activation process.

The manufacturing method according to the present invention includes synthesizing the pitch and then activating the synthesized pitch. At this time, activating the pitch means forming a pore structure in the pitch, and in the case of the present invention, by adjusting the molecular weight in the process of synthesizing the pitch, in the step of activating the pitch, macropores and micropores on the surface of the macropores This is formed to form a multi-pore structure.

As described above, the multi-pore structure having macropores and micropores formed on the surface thereof increases the specific surface area of the electrode material, so that ions can easily flow into the micropores through the macropores, thereby improving electrical properties. there is

In the production method of the present invention, the carbon source may be various organic compounds that can be synthesized into pitch, and for example, petroleum-based residue or coal-based coal tar is preferable. For example, cellulose-based biomass may be considered as the carbon source, but when manufacturing an electrode material through this, a wide specific surface area can be guaranteed, but there is a problem in that conductivity is lowered due to low crystal characteristics. In the manufacturing method of the present invention, it is preferable to use petroleum-based residue oil or coal-based coal tar, through which a highly conductive electrode material can be manufactured, and the problem that is not easily activated is the temperature range control and activation step in the pitch synthesis process can be solved through

In the manufacturing method of the present invention, the step of synthesizing the pitch is preferably performed at a temperature range of 370 to 420 ° C. When the synthesis temperature is less than 370 ℃, there is a problem that the thermal stability of the pitch is low, which can cause the collapse of the pore structure during the activation process. There is a problem that doesn't work.

The temperature range is more preferably in the range of 380 to 400 ° C. in terms of improving the specific surface area of the activated carbon.

In addition, the step of synthesizing the pitch is preferably performed for 1 to 20 hours. If the synthesis time is less than 1 hour, there is a problem in that pitch is not sufficiently synthesized from the carbon source, and if it exceeds 20 hours, the coking reaction due to polymerization proceeds, which is disadvantageous in forming pores on the surface.

On the other hand, in the step of synthesizing pitch in the production method of the present invention, the molecular weight of the components included in the final pitch is adjusted by adjusting the temperature range during synthesis. It is preferably carried out at 20 to 30% by weight relative to the total pitch weight. As described above, since components having a relatively low molecular weight are sufficiently included in the pitch, macropores are sufficiently formed before formation of micropores in a subsequent activation process, so that an electrode material having a desired multi-pore structure can be manufactured.

The step of activating the synthesized pitch in the production method of the present invention is preferably performed by a chemical method or a physical method. Specifically, the chemical method may be understood as a method of forming a pore structure by mixing synthesized pitch and a chemical substance, and the physical method may be understood as a method of forming a pore structure by applying physical force to the synthesized pitch.

Specifically, the chemical method may be performed by mixing the synthesized pitch with a basic solution, and the basic solution is absorbed into the pitch to form a pore structure in the pitch.

In this case, the basic solution is preferably one or more solutions selected from the group consisting of a KOH solution, a NaOH solution, and a H ₃ PO ₄ solution.

In addition, the physical method may be performed by applying steam or carbon dioxide gas to the synthesized pitch, and a pore structure may be formed in the synthesized pitch through this process.

More specifically, in the step of activating the synthesized pitch in the production method of the present invention, the synthesized pitch and KOH are mixed, but the ratio is preferably in the range of 1: 1 to 1: 4 in terms of weight ratio. If the KOH content is less than the above range, there is a problem that the synthesized pitch is not sufficiently activated, and if the KOH content exceeds the above range, the pore structure may collapse and the conductivity may deteriorate. .

The step of activating the pitch synthesized in the manufacturing method of the present invention is preferably performed while raising the temperature from room temperature to 900 ℃. In the process of activating the pitch by performing various methods such as chemical or physical on the synthesized pitch, that is, forming a pore structure in the pitch, the pore structure is formed while raising the temperature from room temperature to a high temperature of 900 ° C. In the temperature range of 500 ° C, macropores are formed while the relatively low molecular weight components contained in the pitch synthesized in the step of synthesizing the pitch are removed, and then micropores are formed on the surface of the macropores in the process of raising the temperature to 900 ° C. formed, it is possible to finally manufacture an electrode material having a multi-pore structure. If the temperature of the activation step exceeds 900 ℃, there is no effect, and there is a problem that the process cost increases.

The activation, for example, transfers the mixture of the synthesized pitch and KOH for activation to an alumina boat, raises the temperature to 850 ℃ at a heating rate of 5 ℃ per minute in a carbonization furnace, and heat-treats at that temperature for 1 hour method can be performed.

In addition, the present invention provides an electrode material produced by the above method and characterized in that it has a multi-pore structure including macropores and micropores formed on the surface thereof.

In the present invention, macropores refer to pores having a pore size of 0.1 μm to 5 μm, and micropores refer to pores having a pore size of 2 nm or less. The electrode material having a multi-pore structure of the present invention is prepared by the above method, so that macropores are first formed by materials having relatively low molecular weight in the activation process, and the surface of the macropores in the process of further raising the temperature. Micropores are formed in the electrode material, and finally, an electrode material having a multi-pore structure is formed.

The electrode material having a multi-pore structure according to the present invention includes macropores and micropores on the surface thereof, so that the specific capacitance increases as the specific surface area increases, and ions can easily pass through the macropores into the micropores. It is accessible, and there is an advantage in that electrical characteristics are improved.

Furthermore, the present invention provides an electric double layer capacitor comprising the above electrode material. The electric double layer capacitor according to the present invention has the advantage of greatly improving electrical characteristics such as specific capacitance and conductivity by including the electrode material having a multi-pore structure as described above.

Hereinafter, the present invention will be described in more detail through Examples, Comparative Examples and Experimental Examples. The following Examples, Comparative Examples and Experimental Examples are merely described as examples to explain the present invention, and are not intended to be construed as limiting the scope of the present invention by the description below.

<Example 1>

Production of activated carbon 1

20 g of pitch obtained by distilling and polymerizing naphtha cracking process residue (PFO) at 370 °C for 3 hours was mixed with potassium hydroxide (KOH) in a weight ratio of 1:1, and the temperature was raised to 850 °C at a heating rate of 5 °C/min. After that, it was maintained for 1 hour to proceed with activation to prepare activated carbon.

<Example 2>

Production of activated carbon 2

20 g of pitch obtained by distilling and polymerizing naphtha cracking process residue (PFO) at 380 °C for 3 hours was mixed with potassium hydroxide (KOH) in a weight ratio of 1:1, and the temperature was raised to 850 °C at a heating rate of 5 °C/min. After that, it was maintained for 1 hour to proceed with activation to prepare activated carbon.

<Example 3>

Manufacture of activated carbon 3

20 g of pitch obtained by distilling and polymerizing naphtha cracking process residue (PFO) at 400 °C for 3 hours was mixed with potassium hydroxide (KOH) in a weight ratio of 1:1, and the temperature was raised to 850 °C at a heating rate of 5 °C/min. After that, it was maintained for 1 hour to proceed with activation to prepare activated carbon.

<Example 4>

Manufacture of activated carbon 5

20 g of pitch obtained by distilling and polymerizing naphtha cracking process residue (PFO) at 420 °C for 3 hours was mixed with potassium hydroxide (KOH) in a weight ratio of 1:1, and the temperature was raised to 850 °C at a heating rate of 5 °C/min. After that, it was maintained for 1 hour to proceed with activation to prepare activated carbon.

<Example 5>

Manufacture of coin cell 1

0.6 g of activated carbon prepared in Example 1, 0.625 g of PVDF 8 wt%, and 0.05 g of acetylene black were mixed, and an electrode slurry was prepared through NMP. It was coated on a Ti plate with a thickness of 300 μm and dried in a vacuum oven at 120 °C for 12 hours. After that, it was punched out to 13.5 Φ. Using this as an electrode, a coin cell was prepared using 6 M KOH as an electrolyte.

<Example 6>

Coin cell manufacturing 2

An electrode slurry was prepared by mixing 0.6 g of activated carbon, 0.625 g of PVDF 8 wt%, and 0.05 g of acetylene black prepared in Example 2, and using N-Methyl-2-pyrrolidone (NMP). It was coated on a Ti plate with a thickness of 300 μm and dried in a vacuum oven at 120 °C for 12 hours. After that, it was punched out to 13.5 Φ. Using this as an electrode, a coin cell was prepared using 6 M KOH as an electrolyte.

<Example 7>

Manufacture of coin cell 3

0.6 g of activated carbon prepared in Example 3, 0.625 g of PVDF 8 wt%, and 0.05 g of acetylene black were mixed, and an electrode slurry was prepared through NMP. It was coated on a Ti plate with a thickness of 300 μm and dried in a vacuum oven at 120 °C for 12 hours. After that, it was punched out to 13.5 Φ. Using this as an electrode, a coin cell was prepared using 6 M KOH as an electrolyte.

<Example 8>

Manufacture of coin cell 4

0.6 g of activated carbon prepared in Example 4, 0.625 g of PVDF 8 wt%, and 0.05 g of acetylene black were mixed, and an electrode slurry was prepared through NMP. It was coated on a Ti plate with a thickness of 300 μm and dried in a vacuum oven at 120 °C for 12 hours. After that, it was punched out to 13.5 Φ. Using this as an electrode, a coin cell was prepared using 6 M KOH as an electrolyte.

<Experimental Example 1>

Confirmation of pore characteristics of activated carbon

The following experiments were performed to confirm the pore characteristics of the activated carbons prepared in Examples 1 to 4.

In order to analyze the specific surface area of the activated carbons prepared in Examples 1 to 4, BET (Brunauer-Emmett-Teller) analysis was performed. From the analyzed BET adsorption isotherm, the micropore volume was calculated through the T-plot method.

The results of the above experiments are shown in Table 1 below.

Pore characteristics of activated carbon S _BET ^One
(m ² /g) V _mi ²
(cm ³ /g) V _t ³
(cm ³ /g) M _f ⁴
(%) activation yield
(wt%) Example 1 1426 0.560499 0.627175 89.37 42.58 Example 2 1820 0.708847 0.745045 95.14 46.25 Example 3 1771 0.686082 0.721899 95.04 54.35 Example 4 1542 0.594384 0.649407 91.53 64.85 1 S _BET : surface area
2 V _mi : micropore volume
3 V _t : total pore volume
4 M _f : non-porosity ratio = V _mi / V _t * 100

According to Table 1, it can be seen that the activated carbons according to the examples of the present invention have a high specific surface area, and in particular, Example 2 shows the highest specific surface area (S _BET ) value. When used as an EDLC electrode, the specific surface area of the material is directly related to the capacity characteristics of the EDLC, and in the case of the method prepared from the present invention, it is a high-capacity EDLC electrode material in a way that can maximize the specific surface area under the same activation process conditions can be manufactured.

<Experimental Example 2>

Check the electrical characteristics of the coin cell

In order to confirm the electrical characteristics of the coin cells manufactured in Examples 5 to 8, the following experiments were performed.

In order to investigate the specific capacitance of the EDLC electrode at different potential scan rates, a cyclic voltammetry test was performed on the coin cells prepared in Examples 5 to 8, wherein the potential scan rate was 10 to 100 mV/s. .

The results of the above experiments are shown in Table 2 below.

Specific capacitance of EDLC electrode Example Specific capacitance (F/g) 10 mV/s 20 mV/s 50 mV/s 100 mV/s Example 5 18.47 16.24 12.38 9.62 Example 6 23.93 22.25 18.88 15.17 Example 7 21.94 19.77 15.40 11.69 Example 8 20.22 18.53 15.28 12.84

According to Table 2, it can be seen that all of the coin cells according to the present invention show excellent specific capacitance, and in particular, Example 6 shows the highest specific capacitance at all potential scanning speeds, and can be used as a high-capacity EDLC electrode. Able to know.

<Experimental Example 3>

Identification of the pore structure of activated carbon

In order to confirm the pore structure of the prepared activated carbon, the following experiment was performed.

A scanning electron microscope (SEM) analysis was performed to observe the shape of the macropores of the activated carbon prepared in Examples 1 to 4.

The results of the above experiments are shown in FIG. 1 .

According to FIG. 1 , it can be confirmed that macropores are actually formed on the surface of activated carbon. When judging by combining the results of FIG. 1 and the results of Table 1, it can be confirmed that the activated carbon produced by the manufacturing method of the present invention has macropores and micropores formed on its surface.

<Experimental Example 4>

Molecular weight distribution analysis of manufactured pitch

In order to confirm the molecular weight distribution of the pitch synthesized by the production method of the present invention, the following experiment was performed.

The molecular weight distribution of the pitch used to prepare the activated carbon was subjected to Maldi-TOF mass spectrometry (MALDI-TOF), and the molecular weight distribution was investigated in the range of 100 to 2000 m/z. In Figure 2, segment1, segment2, segment3, segment4, segment5, segment6, segment7, segment8, segment9, segment10, and segment11 are 100 to 128, 128 to 256, 256 to 384, 384 to 512, 512 to 640, and 640 to 768, respectively. , 768 to 896, 896 to 1024, 1024 to 1152, 1152 to 1280, and 1280 to 1408 indicate the content of components corresponding to the m/z ranges.

The results of the experiment are shown in FIG. 2 . According to FIG. 2, it can be seen that the components of segment2 are contained in a mass ratio of 20 to 30 in the samples of all examples, and in particular, it can be seen that Example 2, which showed the highest specific surface area, showed the highest content of segment2 components. there is.

<Experimental Example 5>

Confirmation of pitch yield, pitch softening point, and specific surface area of activated carbon according to pitch polymerization temperature

In order to confirm the yield of polymerized pitch according to the heating temperature when polymerizing pitch, the softening point of polymerized pitch, and the specific surface area of activated carbon obtained by activating polymerized pitch, the pitch polymerization temperature was 360 ℃, 370 ℃, 380 ℃, Polymerization was performed while changing the temperature to 390 ° C, 400 ° C, 410 ° C, 420 ° C, 430 ° C, 440 ° C, the yield and softening point of the polymerized pitch were measured, and the activated carbon was prepared by activating the polymerized pitch. The specific surface area of the activated carbon was measured, and the results are shown in FIG. 3 .

According to FIG. 3, it can be seen that as the pitch polymerization temperature increases, the low boiling point component in the synthesized pitch decreases, the pitch synthesis yield decreases, and the softening point temperature of the pitch increases. Accordingly, it can be seen that the specific surface area of the activated carbon increases as the pitch synthesis temperature increases, has a maximum value at 390 ° C, and then gradually decreases. Through this, in order to improve the specific surface area of the activated carbon produced, it can be seen that the low boiling point component must be present in an appropriate amount in the pitch to be synthesized, and for this purpose, the temperature range when synthesizing the pitch must be adjusted.

For example, in the case of pitch synthesized at less than 380 ° C., a large amount of low boiling point components are contained, and at the same time, the thermal stability of the pitch is lowered, so that the pore structure may not be maintained by melting during the activation process.

In addition, when synthesized at a temperature higher than 400 ° C., the low boiling point component continuously decreases as the synthesis temperature increases, making it difficult to form a multi-pore structure and thus reducing the specific surface area.

In particular, in the case of pitch synthesized at less than 350 ° C., it exhibits the characteristics of a semi-solid phase (high viscosity liquid phase) at room temperature, and there is a problem that collapse of the pore shape due to rapid volatilization of low boiling point components may occur during the activation process. In addition, in the case of a sample having low thermal properties, since melting occurs simultaneously with the formation of macropores, it is difficult to maintain the shape even if macropores are formed. In addition, in the case of pitch produced at less than 350 ° C., it is difficult to uniformly mix with the activator in the case of a sample that does not form a solid at room temperature, so it is difficult to secure reproducibility even in the process.

Next, when the synthesis temperature of the pitch exceeds 500 ° C., there is a problem in that a multi-pore structure is not formed during the activation process because almost no low-boiling components remain. 4 is a thermogravimetric analysis graph of PFO (Pyrolyzed Fuel Oil), which is a petroleum residue, and it can be seen that the weight reduction trend disappears from 500 ° C. This is due to the carbonization of residue oil, which can be equally confirmed in petroleum residue oil, coal tar, etc., except for PFO. When the pitch synthesis temperature exceeds 500 ° C. through FIG. 4, low boiling point components remain in the synthesized pitch. It can be expected that there will be no

Claims (15)

Synthesizing a pitch containing 20 to 30% by weight of a component having a molecular weight of 128 to 256 based on the total pitch weight by heating petroleum residue at 370 to 420 ° C. and atmospheric pressure for 1 to 20 hours; and
A method for producing activated carbon having a multi-pore structure comprising; activating the synthesized pitch.
delete delete delete delete The method of claim 1, wherein the step of activating the synthesized pitch is performed by a chemical method or a physical method.
The method of claim 6, wherein the chemical method is performed by mixing the synthesized pitch with a basic solution.
The method of claim 7, wherein the basic solution is at least one solution selected from the group consisting of a KOH solution and a NaOH solution.
The method of claim 6, wherein the physical method is performed by adding steam or carbon dioxide gas to the synthesized pitch.
The activated carbon having a multi-pore structure according to claim 1, wherein the step of activating the synthesized pitch is mixing the synthesized pitch and KOH, the ratio of which is in the range of 1: 1 to 1: 4 by weight. How to make a cow.
The method of claim 1, wherein the activating step is performed while raising the temperature from room temperature to 900 °C.
The method of claim 1, wherein the activated carbon produced by the method includes macropores and micropores formed on the surface thereof.
Synthesizing a pitch containing 20 to 30% by weight of a component having a molecular weight of 128 to 256 based on the total pitch weight by heating petroleum residue at 370 to 420 ° C. and atmospheric pressure for 1 to 20 hours; and
Activating the synthesized pitch; manufacturing method of an electrode material comprising a.
14. The method of claim 13, wherein the electrode material manufactured by the manufacturing method has a multi-pore structure including macropores and micropores formed on the surface thereof.
A method of manufacturing an electric double layer capacitor comprising the steps of manufacturing an electrode material by the manufacturing method of claim 13.

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