KR101468589B1 - Bio Activated Carbon for Electric Double Layer Capacitor and Fabrication Method thereof - Google Patents

Abstract

The present invention relates to a biodegradable, The present invention relates to activated carbon and a method for producing the same. The bioactive carbon according to the present invention comprises: (a) mixing raw material and distilled water to form spherical carbonized particles by heating in a reactor; (b) carrying the particles obtained in the step (a) in a solution of the activating additive material so that the activating additive material is impregnated in a state of being evenly dispersed on the surface of the particles; (c) heating the particles having been subjected to the step (b) to activate the particles so that a plurality of pores are formed on the surface of the particles.
Therefore, all the bio-materials composed of three elements such as carbon (C), hydrogen (H), and oxygen (O) are used as starting materials, and in the subsequent processes, there are no additional impurities And active carbon particles effective as an electrode active material for an electric double layer capacitor having a high purity can be obtained.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bioactive carbon for an electric double layer capacitor,

The present invention relates to a biodegradable, More particularly, the present invention relates to activated carbon and a method for producing the activated carbon. More specifically, the present invention relates to a method for producing activated carbon, Activated carbon and a process for producing the same.

Activated carbon is an amorphous carbon with a developed pore structure, and is well known as a material exhibiting excellent adsorption characteristics in vapor and liquid phase. Activated carbon having such characteristics is widely used in various fields such as purification process and atmospheric purification, and is widely used as an electrode active material of an electric double layer capacitor having fast charge / discharge, long life, environment friendly, and wide operating temperature conditions.

Existing activated carbon is mainly manufactured from coconut, pitch, resin and the like which are obtained from palm oil, sawdust and coal or petroleum. However, since these raw materials are hardly produced in Korea, they depend on imports from foreign countries. In Korean Patent Publication No. 10-2010-0019202, raw material of activated carbon is imported at an annual amount of 33,000 tons (320,000 won / ton for carbonized palm kernel), and 17,000 tons / year (1.5 million won / ton for activated carbon finished product) . This is an excessive expenditure on raw materials, which not only leads to a large loss of foreign currency, but also makes it difficult to secure stable raw materials. In addition, when activated carbon is used as the electrode material of the electric double layer capacitor, it should have appropriate pore diameter and particle size together with electric conductivity and high specific surface area. However, coke, phenol and coconut activated carbons, which are used for commercial purposes, are relatively large in particle size and not easily controlled in pore size, and use a large amount of highly corrosive chemicals in the chemical activation process . Therefore, since the lifetime of the process equipment is short and the maintenance cost of the equipment is high, the price of the activated carbon for electric double layer capacitor is high.

In order to solve such conventional problems, the following inventions have been proposed.

Korean Patent Publication No. 10-1998-0005073 discloses a method for producing activated carbon having a high specific surface area of 1110 to 2442 m 2 / g through pretreatment of coffee waste at 300 ° C. and carbonization and chemical activation.

Korean Patent Publication No. 10-2000-0040268 discloses a method for producing activated carbon having a high specific surface area of from 1970 to 2500 m 2 / g by increasing the content of fixed carbon by carbonizing rice hulls and selecting appropriate activation conditions have.

Korean Patent Publication No. 10-2010-0019202 discloses a method for producing an inexpensive activated carbon by activating food waste with potassium sulfide at an activation temperature of 400 ° C to 700 ° C.

In the above conventional techniques, impurities such as sulfur and sodium are remained. These impurities cause an increase in internal resistance and an unnecessary chemical reaction in an electric double layer capacitor requiring only electrical desorption in a solution of charged ions . Such an increase in internal resistance and unnecessary chemical reaction are undesirable because they degrade the output characteristics and lifetime characteristics of the capacitor.

It is an object of the present invention to use all the bio materials composed of a structure in which only three elements of carbon (C), hydrogen (H) and oxygen (O) are connected to each other as raw materials, Biosensors for electric double-layer capacitors consisting of processes not included And a method for producing the same.

Another object of the present invention is to provide a high-purity bi- And a method for producing the same.

It is still another object of the present invention to provide a biodegradable biodegradable polymer for electric double layer capacitor And a method for producing the same.

An object of the present invention is to provide a method of manufacturing a carbon nanotube, comprising: (a) mixing raw material and distilled water and heating in a reactor to form spherical carbonized particles; (b) carrying the particles obtained in the step (a) in a solution of the activating additive material so that the activating additive material is impregnated in a state of being evenly dispersed on the surface of the particles; (c) heating the particles having been subjected to the step (b) to activate the particles to form a plurality of pores on the surface thereof.

In addition, the raw material is composed of three elements of carbon (C), hydrogen (H) and oxygen (O), and preferably includes one selected from the group consisting of saccharides, starch, cellulose and glycogen.

In addition, it is preferable that the surfaces of the particles are activated by the drying, grinding and heating process after the particles are supported on the activated additive material to form pores.

According to another aspect of the present invention, there is provided a method of manufacturing a carbon nanotube, comprising: (a) mixing raw material and distilled water to form spherical carbonized particles by heating in a reactor; (b) carrying the particles obtained in the step (a) in a solution of the activating additive material so that the activating additive material is impregnated in a state of being evenly dispersed on the surface of the particles; (c) heating the particles having been subjected to the step (b) to activate the particles to form a plurality of pores on the surface thereof.

Further, it is preferable that the method further comprises: (d) washing the activated additive material so that the pH is neutral.

Also, in the step (d), the washing method preferably includes hot water washing.

In addition, it is preferable that the activated additive material includes KOH, NaOH, K ₂ CO ₃ , and Na ₂ CO ₃ .

In addition, the raw material is composed of three elements of carbon (C), hydrogen (H) and oxygen (O), and preferably includes one selected from the group consisting of saccharides, starch, cellulose and glycogen.

In the step (a), the heating temperature is preferably in the range of 150 to 250 ° C.

Also, in the step (c), it is preferable to heat in the range of 600 ° C to 1000 ° C in an inert gas atmosphere containing argon gas.

In addition, it is preferable that the step (a) to the step (c) further include a step of filtering and drying after each step.

In addition, it is preferable that the step (a) and the step (b) further comprise a step of pulverizing the particles.

According to the present invention, it is possible to use all the bio-materials having a structure in which only three elements of carbon (C), hydrogen (H) and oxygen (O) are connected to each other as starting materials, Which can increase effective activated carbon particles as an electrode active material for an electric double layer capacitor with high purity and can be used as an environmentally friendly biodegradable polymer for electric double layer capacitors Activated carbon and a method for producing the same.

1 is a flow diagram according to an embodiment of the present invention;
FIGS. 2A to 2E are SEM (Scanning Electron Microscopy) images of bioactive carbon particles according to the kind of starting material according to an embodiment of the present invention,
3A to 3E are SEM images of bioactive carbon particles according to changes in activation temperature of a sample according to an embodiment of the present invention,
FIG. 4 is a graph showing the pore size distribution of the bioactive carbon of FIGS. 3A to 3E,
FIG. 5 is a graph showing the cyclic current charge / discharge test results of the electric double layer capacitor electrode using bioactive carbon treated with starch as starch at an activation temperature of 900 ° C. FIG.
FIG. 6 is a graph showing the capacity in accordance with the scan rate variation calculated based on the data of FIG. 5,
FIG. 7 is a graph showing the results of AC impedance measurement of FIG. 6,
8 is a graph showing the durability test results of the electrode of FIG.

The biodegradability of an electric double layer capacitor according to the present invention The activated carbon and a method for producing the same (hereinafter referred to as "bioactive activated carbon and a method for producing the same") will be described in detail with reference to FIG. 1 to FIG.

FIG. 1 is a flow chart according to an embodiment of the present invention. FIGS. 2A to 2E are SEM images of bioactive carbon particles according to the kind of a starting material according to an embodiment of the present invention, FIG. 4 is a graph showing the pore size distribution of the bioactive carbon of FIGS. 3A to 3E, and FIG. 5 is a graph showing the pore size distribution of the bioactive carbon particles according to an embodiment of the present invention. FIG. 6 is a graph showing the results of cyclic current charging and discharging tests for an electric double layer capacitor electrode using bioactive carbon treated with an activated temperature of 900 ° C as starch, FIG. 6 is a graph showing the ratio FIG. 7 is a graph showing the results of the AC impedance measurement of FIG. 6, and FIG. 8 is a graph showing the results of endurance test of the electrode of FIG.

As shown in FIG. 1, the bioactive carbon and the method for producing the same according to the present invention may include a hydrothermal treatment step (S110), a filtration, a drying and a crushing step (S120), an activated additive material supporting step (S130) (S140), a particle activation step (S150), a cleaning step (S160), and a finishing step (S170). The carbon particles subjected to such a finishing step are preferably referred to as bio-activated carbon, but carbon particles or bio-activated carbon may not be specifically classified depending on the case.

First, in a hydrothermal treatment step (S110), a solution obtained by mixing a raw material biomaterial and distilled water is put into a reactor and heated at 150 to 250 ° C. for 24 hours or longer to remove hydrophilic residues present on the particle surface of the raw material Thereby leading to carbonization with a spherical shape and a size of 10 mu m or less.

Here, the raw material which is a starting material to be applied to the present invention includes all the bio materials having a structure in which only three elements of carbon (C), hydrogen (H) and oxygen (O) are connected to each other. Examples of such raw materials include sugars such as sugar, glucose, lactose, maltose, and oligosaccharides, starch obtained from rice, wheat, potatoes, corn, sweet potatoes and the like, and cellulose derived from green plants, rust, seaweed, Glycogen extracted from vegetable cells, and the like.

Next, the granulated carbon is filtered and separated from the liquid, and the carbonized particles having a water content are dried at about 120 ° C. for 12 hours, and the dried carbon particles are pulverized for about 12 hours through a grinding means including a ball mill S120). The temperature and time for drying in this process and the time for pulverization are not limited to the above-mentioned range and can be variously changed.

The method or means for filtering, drying and crushing the carbon particles can be selected from various known methods.

Next, it is preferable that the ground small carbon particles are mixed with the activated addition material containing the KOH solution, and the surface and pores of the carbon particles serving as the sample are supported for a sufficient time so that the activated addition material can be evenly impregnated (S130). Here, the activated additive material may include not only the KOH solution but also various solutions capable of activating the surface and pores of the carbon particles. For example, alkali metal hydroxides such as NaOH, K ₂ CO ₃ and Na ₂ CO ₃ can be used.

Then, the solution and the carbon particles are filtered, dried and pulverized (S140). The step of filtering, drying and pulverizing (S140) is the same as the above-described step of filtering, drying and pulverizing (S120), so that the explanation thereof will be omitted.

Next, the carbon particles are heated in an inert gas atmosphere containing argon gas for 1 hour at 600 ° C. to 1000 ° C. so that numerous pores can be formed on the surface of the carbon particles (S150). This activation can be further accelerated by the activated additive material impregnated into the particles in the particle activation treatment step (S140). The heating time is one hour but it can be varied.

Next, the activated substance remaining on the carbon particles is removed, and the carbon particles are washed several times so that the pH is neutral (S160). In this process, it is preferable to wash with warm water to improve the cleaning effect.

Next, in the course of washing, the water contained in the activated carbon is removed and dried to obtain bio-active carbon of the final product (S170).

Hereinafter, a manufacturing method, an electrode test example, a method, and a result of an electrode according to an embodiment of the present invention will be described in detail. The present invention is not limited to these examples.

≪ Example 1 >

In this embodiment, starch among the above-mentioned starting materials is selected, and as shown in FIG. 1, bioactive carbon, which is a carbon particle having a spherical shape and a size of 6 μm or less, is prepared through various processes including hydrothermal treatment , Fig. 2A shows an SEM image of carbon particles according to Example 1. Fig.

Here, SEM (Scanning Electron Microscopy) and EDX (Energy Dispersive X-ray Spectroscopy), which confirm the surface morphology and components of the carbon particles, were analyzed by Hitachi S-4800.

≪ Example 2 >

FIG. 2B is a SEM image of the carbon particles according to Example 2. FIG. 2B shows the SEM image of the carbon particles according to Example 2. FIG.

≪ Example 3 >

FIG. 2C is an SEM image of the carbon particles according to Example 3. FIG. 2C is a graph showing the SEM image of the carbon particles according to Example 3. FIG.

<Example 4>

FIG. 2 (d) shows an SEM image of the carbon particles according to Example 4. FIG. 2 (d) shows an SEM image of the carbon particles according to Example 4, wherein glucose is selected from the above-mentioned starting materials by the same procedure as in Example 1. FIG. In this case, spherical carbon particles can not be formed together with spherical carbon particles, or spherical carbon particles are mixed with broken particles.

&Lt; Example 5 >

FIG. 2E is a SEM image of the carbon particles according to Example 5. FIG. 2E is a graph showing the SEM image of the carbon particles according to Example 5. FIG.

&Lt; Example 6 >

The agglomerated spheroidal carbon particles prepared as in Example 1 were pulverized into small particles, and the KOH solution, which is one of the activated additive materials, was used to load the carbon surface and the pores for a sufficient time to uniformly impregnate the KOH solution . The sufficiently supported carbon particles were collected again, filtered, dried and pulverized to prepare a bioactive carbon bearing the catalyst material.

&Lt; Example 7 >

The sample prepared as in Example 6 was heated at an activation temperature of 600 占 폚 for 1 hour to prepare bioactive carbon. The surface morphology of the bioactive carbon observed through the SEM is shown in Fig. 3A, and the EDX for identifying the contained components is shown in Table 1.

The specific surface area of the bioactive charcoal according to this embodiment using the BET method was 894.45 m ² / g, the pore volume was 0.4323 cm ³ / g, and the average pore size was 1.9334 nm. Also, the pore volume using the NLDFT method was 0.6436 cm ³ / g and the average pore size was 1.3351 nm, respectively. The results are shown in Table 2. The pore size distribution of the bioactive carbon according to this embodiment is shown in FIG.

Here, the BET specific surface area and pore size distribution were measured by BELSORP-max in liquid nitrogen (77K). The BET (Brunaucr-Emmett-Teller) method and the NLDFT (Non-Local Density Functional Theory) The same applies.

&Lt; Example 8 >

The sample prepared as in Example 6 was heated at an activation temperature of 700 占 폚 for 1 hour to prepare bioactive carbon. SEM and EDX are shown in FIG. 3B and Table 1, respectively.

The specific surface area of the bioactive carbon to which the BET method according to this embodiment was applied was 1270.6 m ² / g, the pore volume was 0.5148 cm ³ / g, and the average pore size was 1.6208 nm, respectively. Further, when the NLDFT method is applied, the pore volume is 0.7865 cm ³ / g and the average pore size is 1.1671 nm. These results are shown in Table 2, respectively. The pore size distribution of the bioactive carbon according to this embodiment is shown in FIG.

&Lt; Example 9 >

The sample prepared as in Example 6 was heated at an activation temperature of 800 占 폚 for 1 hour to prepare bioactive carbon. SEM and EDX are shown in FIG. 3c and Table 1.

The specific surface area of the bioactive carbon according to the present invention according to the BET method was 1496.5 m ² / g, the pore volume was 0.6277 cm ³ / g, and the average pore size was 1.6778 nm. According to the NLDFT method, the pore volume is 0.95 cm &lt; ³ &gt; / g, and the average pore size is 1.2477 nm. The results are shown in Table 2. The pore size distribution of the bioactive carbon is shown in FIG.

&Lt; Example 10 >

The sample prepared as in Example 6 was heated at an activation temperature of 900 占 폚 for 1 hour to prepare bioactive carbon. SEM and EDX are shown in FIG. 3d and Table 1 below.

The specific surface area of the bioactive carbon according to the present invention by the BET method was 1544.6 m ² / g, the pore volume was 0.7235 cm ³ / g, and the average pore size was 1.8737 nm. According to the NLDFT method, the pore volume is 1.0379 cm ³ / g and the average pore size is 1.5322 nm. The results are shown in Table 2. The pore size distribution of the bioactive carbon according to this embodiment is shown in FIG.

&Lt; Example 11 >

The sample prepared as in Example 6 was heated at an activation temperature of 1000 占 폚 for 1 hour to prepare bioactive carbon. The SEM and EDX are shown in Figure 3e and Table 1.

The specific surface area of the bioactive carbon according to the present invention by the BET method was 1431 m ² / g, the pore volume was 0.7952 cm ³ / g, and the average pore size was 2.2228 nm. Further, when the NLDFT method is applied, the pore volume is 1.0908 cm ³ / g and the average pore size is 1.3351 nm. The results are shown in Table 2. The pore size distribution of the bioactive carbon according to this embodiment is shown in FIG.

division Weight% Atomic% C O K C O K 600 ℃ 84.98 14.32 0.70 88.58 11.20 0.22 700 ℃ 81.05 18.55 0.40 85.22 14.65 0.13 800 ° C 84.58 15.11 0.31 88.11 11.77 0.12 900 ℃ 86.27 13.73 89.39 10.61 1000 ℃ 86.43 13.57 89.46 10.54

Activation temperature
(° C) BET method NLDFT method Non-surface
(M &lt; 2 &gt; / g) Pore Volume
(Cm3 / g) Average Pore
(nm) Pore Volume
(Cm3 / g) Average Pore
(nm) 600 ℃ 894.45 0.4323 1.9334 0.6436 1.3351 700 ℃ 1270.60 0.5148 1.6208 0.7865 1.1671 800 ° C 1496.50 0.6277 1.6778 0.9500 1.2477 900 ℃ 1544.60 0.7235 1.8737 1.0379 1.5322 1000 ℃ 1431.00 0.7952 2.2228 1.0908 1.3351

&Lt; Example 12 >

An electric double layer capacitor electrode was prepared using the bioactive carbon prepared as in Example 10, and a cyclic current charge / discharge test was performed through a half electrode experiment. The results of the cyclic current charge and discharge tests are shown in FIG. 5, and the specific capacities calculated through the cyclic current charge and discharge test are 248.5 F / g at a scanning speed of 5 mV / s and 205.4 F / / g, respectively, from 500 mV / s to 137.5 F / g respectively.

Here, a slurry was prepared by adding 10 wt% of carbon black and 7 wt% of polyvinylidene fluoride (PVdF) to 83 wt% of bioactive carbon prepared according to the activation temperature condition, and the slurry was formed into a nickel foam current collector having a thickness of 280 μm and an area of 2 × ² cm ² To prepare an electrode.

In addition, the prepared electrode was measured for cyclic current charging and discharging characteristics and alternating current impedance through a half-cell test in a cyclic voltammetry using a 6M KOH solution.

&Lt; Example 13 >

The AC impedance was measured using the electric double layer capacitor electrode manufactured as in Example 12, and the result was expressed as Nyquist Plot. As a result, Equivalent Series Resistance (ESR) was confirmed to be 0.26? Fig.

&Lt; Example 14 >

The durability test results of cycling current charging and discharging repetition in Example 12 using an electric double layer capacitor electrode manufactured as in Example 12 over 100,000 cycles at a charge-discharge scanning rate of 200 mV / s are shown in FIG. 8, And it showed excellent performance maintaining the capacity of 91.26% compared to the initial value.

According to this embodiment of the present invention, raw material is mixed with water and heated after heating to remove unnecessary components by a simple process, forming spherical carbon particles, activating the surface of the carbonized particles, Pores can be formed, and it can be seen that it is environment-friendly because no additive substance other than the activated additive substance is added, and as can be seen from the above-described experimental results, active carbon particles effective as an electrode active material for electric double layer capacitor with high purity can be obtained.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the invention. will be. The scope of the invention will be determined by the appended claims and their equivalents.

Claims (12)

(a) mixing raw material and distilled water and heating in a reactor to form spherical carbonized particles; (b) carrying the particles obtained in the step (a) in a solution of the activating additive material so that the activating additive material is impregnated in a state of being evenly dispersed on the surface of the particles; (c) heating the particles having been subjected to the step (b) to activate the particles so that a plurality of pores are formed on the surface of the particles. The method according to claim 1,
The raw material is composed of three elements of carbon (C), hydrogen (H) and oxygen (O)
Sugar, starch, cellulose, and glycogen. 3. The method according to claim 1 or 2,
Wherein the particles are impregnated into the activated additive material, and the surface of the particles is activated through drying, grinding and heating to form pores. (a) mixing raw material and distilled water and heating in a reactor to form spherical carbonized particles;
(b) carrying the particles obtained in the step (a) in a solution of the activating additive material so that the activating additive material is impregnated in a state of being evenly dispersed on the surface of the particles;
(c) heating the particles after the step (b) to activate the particles to form a plurality of pores on the surface thereof. 5. The method of claim 4,
(d) removing the activated additive material and washing the activated carbon to neutralize the pH. 6. The method of claim 5,
Wherein the washing method in step (d) comprises hot water washing. 5. The method of claim 4,
Wherein the activated additive material comprises KOH, NaOH, K ₂ CO ₃ , and Na ₂ CO ₃ . 5. The method of claim 4,
The raw material is composed of three elements of carbon (C), hydrogen (H) and oxygen (O)
Wherein the bioactive carbon is one selected from the group consisting of sugars, starches, cellulose and glycogen. 5. The method of claim 4,
Wherein the heating temperature in the step (a) ranges from 150 ° C to 250 ° C. 5. The method of claim 4,
Wherein the step (c) is performed in an inert gas atmosphere containing argon gas at a temperature ranging from 600 ° C to 1000 ° C. 5. The method of claim 4,
Wherein the step (a) to the step (c) further comprises a step of filtering and drying after each step. 12. The method of claim 11,
The method of claim 1, further comprising the step of pulverizing the particles after each of the steps (a) and (b).

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