KR100343334B1 - An activated carbon fiber and a process of preparing for the same - Google Patents

Abstract

The present invention relates to an activated carbon fiber, characterized in that the specific surface area is 2,000 m 2 / g or more, and at least 50% of the total surface area is formed of Mesopore having a pore size of 50 mm 3 or more.

According to the present invention, a coal soft pitch is prepared by using a Lewis catalyst and a halogen element as a co-catalyst to produce a pitch of low softening point by condensation polymerization, and fractionated using an inert gas, followed by precursor pitch of isotropic carbon fibers. Manufacture. The precursor pitch is spun to produce metal-containing pitch fibers without metal removal. This pitch fiber is carbonized at 600 ° C. and 1000 ° C. after oxidation stabilization, and activated by water vapor to produce activated carbon fibers. The present invention is characterized in that the Lewis acid metal catalyst used as the polycondensation catalyst remains in the precursor pitch and isotropic carbon fiber as it is, and then used as an oxidation catalyst in the carbonization process.

The present invention is used for solvent adsorption regeneration, odor removal, methane storage, electrodes of lithium ion batteries, fuel cells and the like.

Description

Activated carbon fiber and a method of manufacturing the same {An activated carbon fiber and a process of preparing for the same}

The present invention relates to activated carbon fibers and a method of manufacturing the same.

Activated carbon fiber has unique characteristics compared to general activated carbon. Activated carbon fiber has very high adsorption capacity because it shows very fast adsorption in pores in gaseous phase or liquid phase adsorption because micropores are uniformly developed on thin carbon fiber with diameter of 15㎛ or less. Since the basic form of activated carbon fiber is fibrous, it can be processed into a woven or nonwoven fabric and is easy to handle. In addition, since it is easy to detach at a low temperature, it is an advantage of excellent regeneration. The unique characteristics of activated carbon fibers are used for adsorption and regeneration of solvents, odor removal, methane storage, lithium ion battery electrodes, electric double layer capacitor electrodes, fuel cells, carbon dioxide adsorption, and gas separation.

The micropores uniformly developed on the fiber surface have a larger specific surface area than the activated carbon and are easy to use as a selective adsorbent for small molecules. Most of the activated carbon and activated carbon fibers produced so far are mostly micropores, and there are few reports of selective development of mesopore. Therefore, most of the studies on the pore characteristics are related to micropores. When micropores are mainly formed in activated carbon fibers, there is a problem in that the adsorption of trading molecules or ions is restricted and thus the high capacity as a capacitor electrode cannot be expressed.

Pyrolysis and polycondensation of organic compounds, such as aromatic hydrocarbons, to produce precursor pitches, or polytars of coal tar or petroleum pitches are catalyzed, and then fractionated with an inert gas to prepare precursor pitches, which are then spun to form isotropic carbon fibers. It has been produced and activated carbon fiber by stabilizing, carbonizing and activating it.

A catalyst was used to synthesize the pitch from aromatic hydrocarbons. Naphthalene was polymerized using an alkali metal catalyst such as potassium to form isotropic pitch and Lewis acid such as AlCl ₃ or HF / BF ₃ as a catalyst. It is known that when used, mesophase pitch is formed [I. Mochida, EI Nakamura, K. Maeda and K. Takeshida, Carbon, 13, 489 (1975) and the like.

AlCl ₃ catalysts, however, promote condensation but are difficult to remove from high viscosity pitches and are difficult to reuse because they are removed with hydroxides such as AlCl ₃ OH. In addition, metals that are not completely removed during the carbon fiber manufacturing process may cause structural degradation during carbonization or graphitization, thereby causing mechanical properties to be degraded.

In the case of coal tar or petroleum pitch, first, the primary quinoline insoluble material which does not melt at high temperature should be removed before the pitch is manufactured. Since the natural pitch from which the primary quinoline insoluble substance has been removed is mostly composed of a low molecular weight compound, a precursor pitch capable of oxidative stabilization after spinning is polymerized using a catalyst or the like and subjected to heat treatment, nitrogen fractionation, and air fractionation.

Yang Kap-seung, Kyung Soo Kim, Yung-am Kim, Kye-hyuk Ahn, Abstract of 117 (1996), coal tar and petroleum by-products such as p-nitroaniline, p-benzoquinone, nitro After polycondensation using an aromatic compound such as benzene (nitrobenzene) or a halogen element such as bromine, the unreacted low-molecular weight compound was removed through nitrogen or air fractionation, and then prepared as a precursor.

On the other hand, as the molecular size of the precursor increases, the stacking between molecules becomes difficult, and the fraction of the isotropic structure is reported, and the carbon fiber prepared therefrom exhibits an isotropic structure in cross section.

In addition, when synthesizing the precursor, an experimental result of the development of mesopore was developed by the metal ion when using the metal ion [H. Tamai, S. Kojima, M. Ikeuchi, J. Mondori, T. Kanata and H. Yasuda, TANSO, 175, 243 (1996) and the like.

In addition, it has been reported that the selective adsorption of macromolecules is superior to that of activated carbon with mesopore and mesopore due to the action of metal ions in the production of activated carbon fibers by the synthesis of pitch and organometallic complexes. [T. Matsuo, H. Komagata and Y. Suzuki, Kagaku kogaku, 43, 232 (1979) et al.

However, Lewis acid-based catalysts containing metals are effective for oligomerizing pitch, but the crystallized metal component is puffed during the carbonization process of carbon fiber, thereby destroying the structure of the fiber and deteriorating physical properties. It is becoming. Therefore, it is not only a hassle to remove the metal catalyst after polymerization, but is also difficult to remove because it is surrounded by polymerized hydrocarbons.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing activated carbon fibers which can prevent the destruction of fiber structure and the deterioration of physical properties without removing the metal catalyst remaining in the activated carbon fibers while solving the problems of the prior arts. In addition, the present invention is to produce an activated carbon fiber is easy to adsorb macromolecules, ions, etc. are formed a lot of mesopoie in the fiber without deterioration of physical properties.

In the present invention, when the fiber is prepared and carbonized without removing the metal of Lewis acid used as the polycondensation catalyst, Mespoore is used as the oxidation catalyst by using the metal transferred to the fiber surface as the oxidation catalyst. It is for producing an activated carbon fiber which is adjusted to% or more and exhibits a high specific surface area of 2000 m 2 / g or more.

When gas phase activation of existing pitch-based isotropic carbon fibers is activated carbon fibers, 10 ~ 20Å of micropores are mainly produced, and the specific surface area is limited to 2000㎡ / g. It is important to generate mesopoeas of 50 kPa or more because such micropores have limited adsorption of macromolecules or ions and thus do not express high capacities as capacitor electrodes.

Therefore, the present invention is composed of Mespoore (Mespore) of 50% or more of the pore size of the total fiber surface area, using a metal-containing catalyst during polycondensation to produce activated carbon fibers with a specific surface area of 2000㎡ / g or more . The metal-containing catalyst is then moved from the fiber center to the surface in the carbonization process. The present invention uses the metal-containing catalyst moved to the fiber surface as an oxidation catalyst to prepare activated carbon fibers in which 50% or more of the surface area is formed of 50 kPa of mesopoie without deteriorating the fiber properties or destroying the structure.

1 is a schematic diagram of a precursor pitch manufacturing apparatus used in the present invention.

Figure 2 is a schematic diagram of the device for spinning carbon fiber used in the present invention.

Figure 3 (a) is a transmission electron microscope (TEM) photographic copy of the carbon fiber carbonized at 600 ℃ in Example 1.

(b) is a transmission electron microscope (TEM) photographic copy of carbon fiber carbonized at 600 ° C. in Example 2.

(c) is a transmission electron microscope (TEM) photographic copy of carbon fiber carbonized at 600 ° C. in Example 3.

(d) is a transmission electron microscope (TEM) photographic copy of carbon fiber carbonized at 600 ° C. in Comparative Example 1. FIG.

Figure 4 (a) is a transmission electron microscope (TEM) photographic copy of the carbon fiber carbonized at 1000 ℃ in Example 4.

(b) is a transmission electron microscope (TEM) photographic copy of carbon fiber carbonized at 1000 ° C. in Example 5.

(c) is a transmission electron microscope (TEM) photographic copy of carbon fiber carbonized at 1000 ° C. in Example 6.

(d) is a transmission electron microscope (TEM) photographic copy of carbon fiber carbonized at 1000 ° C. in Comparative Example 1. FIG.

Figure 5 (a) is a scanning electron microscope (SEM) photographic copy of the activated carbon fiber after carbonization 600 ° C in Example 1.

(b) is a scanning electron microscope (SEM) photographic copy of activated carbon fibers after 600 ° C. carbonization in Example 2. FIG.

(c) is a scanning electron microscope (SEM) photographic copy of activated carbon fiber after 600 ° C. carbonization in Example 3.

(d) is a scanning electron microscope (SEM) photographic copy of activated carbon fibers after 600 ° C. carbonization in Comparative Example 1. FIG.

Figure 6 (a) is a scanning electron microscope (SEM) photographic copy of the activated carbon fiber after 1000 ℃ carbonization treatment in Example 4.

(b) is a scanning electron microscope (SEM) photographic copy of activated carbon fiber after 1000 ° C. carbonization in Example 5.

(c) is a scanning electron microscope (SEM) photographic copy of activated carbon fibers after carbonization at 1000 ° C. in Example 6.

(d) is a scanning electron microscope (SEM) photographic copy of activated carbon fiber after 1000 ° C. carbonization in Comparative Example 1. FIG.

※ Code explanation for main part of drawing

1: motor 2, 4: N ₂ gas inlet 3: bromine gas (Br ₂ )

5: condensation furnace (Furnace) 6: temperature control device 7: gas outlet

8: Thermocouple (Termo couple) 9: Valve

10: Gauge 11: Vent 12: N ₂ gas

13 heating element 14 temperature control device

15: nozzle 16: pitch fiber 17: winder

The present invention relates to activated carbon fibers and a method of manufacturing the same.

More specifically, the present invention relates to an activated carbon fiber, characterized in that the specific surface area is 2,000 m 2 / g or more, and 50% or more of the total surface area is formed of mesopore having a pore size of 50 mm 3 or more.

In the present invention, the coal tar pitch is polycondensed under a catalyst, followed by fractionation with an inert gas to prepare a precursor pitch, followed by spinning to produce isotropic carbon fibers, which are then stabilized, carbonized and activated to produce activated carbon fibers. The present invention relates to a method for producing activated carbon fibers characterized in that a Lewis acid metal-containing catalyst and a halogen element are used as a cocatalyst during polycondensation, and a H ₂ O / N ₂ mixed gas is used for activation.

Hereinafter, the present invention will be described in detail.

First, in the present invention, a coal tar pitch is polycondensed using a Lewis acid metal-containing catalyst and a halogen element as a cocatalyst, and then fractionated with an inert gas to prepare a precursor pitch containing metal. More specifically, as a polycondensation raw material, coal tar pitch generated as a by-product during the production of coke is pulverized, dissolved in tetrahydrofuran (hereinafter referred to as 'THF'), and a primary quinoline insoluble substance present therein It is preferable to use a pitch of the softening point 85 ℃ (hereinafter referred to as 'TSP') prepared by separating and removing.

As the Lewis acid metal-containing catalyst, AgBr, AlCl ₃ , or FeCl ₃ is used, and the amount thereof is preferably 3 to 10 wt% based on the total weight of the TSP. Bromine (Br) or the like is used as the halogen element as the cocatalyst, and the amount of addition is preferably 10 to 20% by weight based on the total weight of the TSP. The softening point of the low softening point pitch prepared in this way is 250 ~ 310 ℃.

After adding a Lewis acid metal-containing catalyst to the TSP (raw material), it is dispersed at room temperature, and then polycondensed by adding a halogen element as a cocatalyst at a temperature of about 180 ℃ to produce a pitch of the low softening point. At this time, in order to produce a pitch of a low softening point suitable for stabilization, after heating up to about 350 ° C. at a temperature rising rate of 10 ° C./min or less, it is preferable to keep it for 1 to 5 hours.

Next, a precursor pitch is prepared by removing volatile matter in the pitch for 3 to 9 hours while precipitating an inert gas such as nitrogen (N ₂ ) at a rate of 1.5 L / min. The softening point of the precursor pitch is 250 to 300 ° C. 1 is a schematic diagram of an apparatus used to produce a precursor pitch.

Next, the prepared pitch is spun to prepare isotropic carbon fibers, and then, stabilized, carbonized and activated with H ₂ O / N ₂ mixed gas to prepare activated carbon fibers. Before spinning the prepared precursor pitch, it is preferable to remove the low molecular weight volatiles remaining in the precursor pitch by maintaining the temperature at a temperature of 40 to 50 ° C. higher than the precursor pitch softening point for about 1 hour. The spinning temperature of the precursor pitch is preferably set to 20-30 ° C higher than the softening point of the precursor pitch. 2 is a schematic view of the spinning apparatus of the present invention.

The oxidized fiber is first subjected to primary oxidation stabilization for 2 to 5 hours at an elevated temperature of 10 ° C./min or lower at a temperature of 10 ° C. or lower than the softening point. Secondary oxidation stabilizes over time. This oxidation stabilization process is intended to prevent the fibers from melting during the subsequent carbonization process.

Subsequently, the carbon fiber is oxidatively stabilized at 600 to 1000 ° C. for about 1 hour, and the activated carbon fiber of the present invention is activated under a mixed gas atmosphere of 900 ° C. H ₂ O / N ₂ (mixture ratio 4/10). To prepare.

The activated carbon fiber of the present invention prepared as described above has a specific surface area of 2000 m 2 / g or more, and at least 50% of the total surface area is formed of mesopore (Mespore). As a result, it is useful for the adsorption of macromolecules, especially as a capacitor electrode.

The present invention uses a Lewis acid-based metal catalyst with a co-catalyst of a halogen element during the polycondensation process for producing a precursor pitch, and then oxidizes the carbon catalyst without removing the metal catalyst present in the precursor pitch or isotropic carbon fiber. It is characterized by using as a catalyst. The metal catalyst remaining in the fiber moves from the fiber center to the surface during the carbonization process.

When the carbon fiber is activated with a H ₂ O / N ₂ mixed gas, the degree of activation varies depending on the size and position of the metal crystal, thereby easily forming mesophores in the fiber and maximizing the specific surface area of the fiber. do.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. However, the present invention is not limited only to the following examples.

Example 1

Coal tar pitch is first pulverized with a mill and then dissolved in tetrahydrofuran (THF) to remove primary quinoline insoluble material to produce a pitch (TSP) having a softening point of 85 ° C. AgBr of 3 wt% was uniformly dispersed with respect to 150 g of the prepared TSP, and then reacted while adding 15 wt% Br ₂ using the reactor shown in FIG. 1. In order to prepare a pitch having a softening point suitable for stabilization, a softening point of 260.2 ° C. was produced by raising the temperature to 5 ° C./min to 330 ° C. and maintaining it for 4 hours and then blowing it with N ₂ for 6 hours. . The prepared pitch was used to prepare the spinning fiber using the spinning machine of FIG. 2. The prepared fiber was stabilized for 2 hours at 270 ℃, 3 hours at 300 ℃ to prepare a stabilizing fiber. The stabilized fiber was carbonized at 600 ° C. for 1 hour. Table 1 summarizes the reaction yield and the carbonization yield of the prepared precursor pitch. The stabilized fiber thus produced was carbonized and its transmission electron microscope (TEM) photograph is shown in FIG. 3 (a). In the photo, Ag crystallized uncrystallized inside the fiber. Carbonized carbonized fibers were activated using H ₂ O / N ₂ mixed gas (mixing ratio 4/10) at 900 ° C. for 30 minutes. Figure 5 (a) is a photograph of a scanning electron microscope (SEM) of the fiber thus activated. The properties of the prepared activated carbon fibers are shown in Table 2.

Example 2

Coal tar pitch is first pulverized with a mill and then dissolved in tetrahydrofuran (THF) to remove primary quinoline insoluble material to produce a pitch (TSP) having a softening point of 85 ° C. 3 wt% AlCl ₃ was uniformly dispersed with respect to 150 g of the prepared TSP, and reacted with 15 wt% Br ₂ using the reactor shown in FIG. 1. In order to prepare a pitch having a softening point suitable for stabilization, the temperature was raised to 340 ° C. at a heating rate of 5 ° C./min, maintained for 2 hours, and then blown for 13 hours with N ₂ to produce a radiant pitch of 263 ° C. . The prepared pitch was used to prepare the spinning fiber using the spinning machine of FIG. 2. The prepared fibers were stabilized at 250 ° C. for 3 hours and at 270 ° C. for 5 hours to prepare stabilized fibers. The stabilized fiber was carbonized at 600 ° C. for 1 hour. Table 1 summarizes the reaction yield and the carbonization yield of the prepared precursor pitch. The stabilized fiber thus produced was carbonized and its transmission electron microscope (TEM) photograph is shown in FIG. 3 (b). In the photograph, it was observed that Al metal which was not crystallized was dispersed on the fiber surface side. Carbonized carbonized fibers were activated using H ₂ O / N ₂ mixed gas (mix ratio 4/10) at 900 ° C. for 30 minutes. Figure 5 (b) is a photograph of a scanning electron microscope (SEM) of the fiber thus activated. The properties of the prepared activated carbon fibers are shown in Table 2.

Example 3

Coal tar pitch is first pulverized with a mill and then dissolved in tetrahydrofuran (THF) to remove primary quinoline insoluble material to produce a pitch (TSP) having a softening point of 85 ° C. 3 wt% of FeCl ₃ was uniformly dispersed with respect to 150 g of the prepared TSP, and then reacted with 15 wt% of Br ₂ using the reactor shown in FIG. 1. In order to prepare a pitch having a softening point suitable for stabilization, the temperature was raised to 340 ° C. at a heating rate of 5 ° C./min, maintained for 1 hour, and then blown for 8 hours with N ₂ to produce a spinable pitch of 302.5 ° C. . The prepared pitch was used to prepare the spinning fiber using the spinning machine of FIG. 2. The prepared fibers were stabilized at 300 ° C. for 3 hours to prepare stabilized fibers. The stabilized fiber was carbonized at 600 ° C. for 1 hour. Table 1 summarizes the reaction yield and the carbonization yield of the prepared precursor pitch. The stabilized fiber thus produced was carbonized and its transmission electron microscope (TEM) photograph is shown in FIG. 3 (c). In the photograph, it was observed that Fe metals were dispersed in clusters on the fiber surface area. Carbonized carbonized fibers were activated using H ₂ O / N ₂ mixed gas (mixing ratio 4/10) at 900 ° C. for 30 minutes. Figure 5 (c) is a photograph of a scanning electron microscope (SEM) of the fiber thus activated. The properties of the prepared activated carbon fibers are shown in Table 2.

Example 4

Activated carbon fiber was prepared in the same process and conditions as in Example 1 except that the carbonization temperature was changed to 1000 ° C. Table 1 summarizes the reaction yield and the carbonization yield of the prepared precursor pitch. A transmission electron microscope (TEM) photograph carbonized at 1000 ° C. is shown in FIG. 4 (a). Crystallized Br metal in the photo was observed inside the fiber. Figure 6 (a) is a scanning electron microscope (SEM) photograph of the activated fiber after carbonization at 1000 ℃. The properties of the prepared activated carbon fibers are shown in Table 2.

Example 5

Activated carbon fibers were manufactured under the same process and conditions as in Example 2, except that the carbonization temperature was changed to 1000 ° C. Table 1 summarizes the reaction yield and the carbonization yield of the prepared precursor pitch. A transmission electron microscope (TEM) photograph carbonized at 1000 ° C. is shown in FIG. 4 (b). It was observed that crystalline graphite bands were formed around the cluster of the Al metal crystallized in the photograph. Figure 6 (b) is a scanning electron microscope (SEM) photograph of the activated fiber after carbonization at 1000 ℃. The properties of the prepared activated carbon fibers are shown in Table 2.

Example 6

Activated carbon fiber was prepared in the same process and conditions as in Example 3 except that the carbonization temperature was changed to 1000 ° C. Table 1 summarizes the reaction yield and the carbonization yield of the prepared precursor pitch. A transmission electron microscope (TEM) photograph carbonized at 1000 ° C. is shown in FIG. 4 (c). In the photograph, it was observed that a highly crystalline graphitized band was formed around the crystallized Fe metal. Figure 6 (c) is a scanning electron microscope (SEM) photograph of the activated fiber after carbonization at 1000 ℃. The properties of the prepared activated carbon fibers are shown in Table 2.

Comparative Example 1

Coal tar pitch is first pulverized with a mill and then dissolved in tetrahydrofuran (THF) to remove primary quinoline insoluble material to produce a pitch (TSP) having a softening point of 85 ° C. The prepared TSP 150g was reacted while adding 15% by weight of Br ₂ using the reactor shown in FIG. 1. In order to produce a pitch having a softening point suitable for stabilization, a radiating pitch of 253.8 ° C. was prepared by raising the temperature to 5 ° C./min to 340 ° C. and maintaining it for 2 hours, and then blowing with N ₂ for 10 hours. . The prepared pitch was used to prepare the spinning fiber using the spinning machine of FIG. 2. The prepared fibers were stabilized at 240 ° C. for 3 hours and at 300 ° C. for 3 hours to prepare stabilized fibers. The stabilized fiber was carbonized at 600 ° C. for 1 hour. Table 1 summarizes the reaction yield and the carbonization yield of the prepared precursor pitch. The stabilized fiber thus produced was carbonized and its transmission electron microscope (TEM) photograph is shown in FIG. 3 (d). The picture shows an isotropic carbon fiber structure. Carbonized carbonized fibers were activated using H ₂ O / N ₂ mixed gas (mixing ratio 4/10) at 900 ° C. for 30 minutes. Figure 5 (d) is a photograph of a scanning electron microscope (SEM) of the fiber thus activated. The properties of the prepared activated carbon fibers are shown in Table 2.

Comparative Example 2

Activated carbon fibers were manufactured under the same process and conditions as in Comparative Example 1 except that the carbonization temperature was changed to 1000 ° C. Table 1 summarizes the reaction yield and the carbonization yield of the prepared precursor pitch. A transmission electron microscope (TEM) photograph carbonized at 1000 ° C. is shown in FIG. 4 (d). The picture shows an isotropic carbon fiber structure. Figure 6 (d) is a scanning electron microscope (SEM) photograph of the activated fiber after carbonization at 1000 ℃. The properties of the prepared activated carbon fibers are shown in Table 2.

Precursor pitch reaction yield and carbonization yield division Softening point (℃) yield(%) Precursor Pitch Response Yield Carbon yield Example 1 260.2 74.0 81.0 Example 2 263.0 63.3 85.6 Example 3 302.5 85.2 68.1 Example 4 260.2 74.0 75.4 Example 5 263.0 63.3 65.4 Example 6 302.5 85.2 66.1 Comparative Example 1 253.8 62.0 78.7 Comparative Example 2 253.8 62.0 85.5

Activated Carbon Fiber Properties division Burn off [%] Surface area [㎡ / g] Mespoore area [㎡ / g] Micropore area [㎡ / g] Average pore size [Å] Example 1 77 3,012 1,640 1,327 16.0 Example 2 66 1,397 869 528 14.8 Example 3 77 3,676 2,527 1,249 17.0 Example 4 19 1,739 - - 17.7 Example 5 8.0 1,083 - - 18.7 Example 6 5.3 909 - - 12.0 Comparative Example 1 60 1,149 207 942 12.0 Comparative Example 2 8.6 407 - - 19.3

The manufacturing method of the present invention can simplify the process of removing the metal compound used as a catalyst in the precursor production without destroying the structure of the fiber or degradation of physical properties. In addition, in the activated carbon fiber of the present invention, at least 50% of the total surface area of the fiber is formed at 50 kPa or more, and the specific surface area of the fiber is 3,000 m 2 / g or more, which is very high compared to the conventional pitch-based isotropic activated carbon fiber. It is useful for adsorption, especially as a capacitor electrode.

Claims (7)

Activated carbon fiber, characterized in that the specific surface area is more than 2,000㎡ / g, 50% or more of the total surface area is formed of mesopore (Mesopore) having a pore size of 50Å or more. Coal tar pitch is polycondensed under a catalyst and then fractionated with an inert gas to prepare precursor pitch, which is then spun to produce isotropic carbon fibers, and then to stabilize, carbonize and activate them to produce activated carbon fibers. Lewis) A method for producing activated carbon fibers, characterized in that an acidic metal-containing catalyst and a halogen element are used as co-catalysts, and H ₂ O / N ₂ mixed gas is used for activation. The method according to claim 2, wherein the precursor pitch and the isotropic carbon fiber spun therein contain a metal. The method of claim 2, wherein the Lewis acid metal-containing catalyst is AgBr, AlCl ₃ or FeCl ₃ . The method according to claim 2, wherein the amount of Lewis acid-based metal-containing catalyst is 3 to 10% by weight based on the total weight of the polycondensate. The method of claim 2, wherein the polycondensation raw material is prepared by removing primary qninoline insoluble material from coal tar pitch and uses a pitch having a softening point of 85 ° C. The method for producing activated carbon fibers according to claim 2, wherein the carbonization temperature is 600 to 1,000 ° C.