KR100351131B1 - High dense activated carbon fiber disk for capacitor's electrode of ultra high capacity and its production method - Google Patents

Abstract

According to the present invention, after oxidative stabilization of a pitch fiber melt-spun from an optically isotropic pitch-based carbon fiber precursor, a high-density incompatible fiber is obtained by pressing a fiber in which the fiber is infusified without using a binder as a binder of carbon fiber. The present invention relates to a high density capacitive activated carbon fiber disk for ultracapacitor electrode materials produced by converting the disk into carbon and appropriately carbonizing and activating the high density immobilized fiber disk, and a method of manufacturing the same.

The densified activated carbon fiber discs for ultra-capacitor electrode materials have a packing density of 0.2-1.5 g / cc without binder, and the manufacture of the discs involves melt spinning a pitch-based carbon fiber precursor having a softening point of 250 ° C. or higher. (11) making pitch fibers, oxidizing infusively treating the melt-spun pitch fibers at 200 to 340 ° C. (12) converting them into incompatible fibers, and charging infused fibers into a molder (13) After pressurizing (14) the impregnated fiber loaded into the molder at a pressure of 2 to 20 MPa in the range of 300 to 450 ° C. to make a densified incompatible fiber disc, and carbonizing the densified incompatible fiber disc under an inert atmosphere (15). Activating the densified carbon fiber discs using a step of converting the densified carbon fiber discs and using steam having a water vapor / nitrogen ratio of 0.3 to 0.5 at a temperature of 700 to 950 ° C. (16) Converting to a longitudinal densified activated carbon fiber disc.

According to the present invention, the method for producing a densified activated carbon fiber disk for an ultra high capacity capacitor electrode material is capable of densifying carbon fibers even without a binder, so that the fine pores generated in the carbon fibers through the activation process are rendered ineffective by the binder. As a result, the specific surface area can be maximized by the same weight, and thus the densified activated carbon fiber disk produced by the method of the present invention can be used not only as a capacitor electrode but also as a high-performance carbon fiber material such as an adsorbent. The use of raw materials has the advantage of lowering the manufacturing cost of carbon fiber materials

Description

High dense activated carbon fiber disk for capacitor's electrode of ultra high capacity and its production method}

The present invention relates to a densified activated carbon fiber disk for ultra-high capacity capacitor electrode materials and a method of manufacturing the same, and more particularly, after oxidative stabilization of the pitch fiber melt-spun from an optically isotropic pitch-based carbon fiber precursor. Manufactured by heating and pressurizing the incompatible fiber in which the pitch fiber is infusified without using a binder, which is a carbon fiber binder, to change into a high density incompatible fiber disk, and carbonizing and activating the high density incompatible fiber disk appropriately. The present invention relates to a densified activated carbon fiber disk for an ultra high capacity capacitor electrode material and a method of manufacturing the same.

In order to increase the capacitance of a capacitor as a medium for storing energy, it is important to make a material having a large specific surface area. Above all, representative materials widely used for such use are activated carbon and activated carbon fiber.

The reason why such carbon-based materials are selected for electrochemical applications is that they are characterized by high electrical conductivity, thermal conductivity, low density, adequate corrosion resistance, low thermal expansion and high purity, and powder, fiber, woven fabric and foam. This is because it can be produced in a wide variety of forms, such as paper.

In addition, compared to other types of capacitor electrode material, it is easy to obtain the raw material of the material and has the advantage of being relatively inexpensive.

In the capacitor of a carbon-based electrode in which a carbon material having a large specific surface area is used to obtain a high capacitance, the capacitance and discharge rate of the capacitor may vary greatly depending on the type of electrolyte, the charge and discharge conditions, and the physical and chemical properties of the carbon-based material. have.

That is, the capacitance of the capacitor of the carbon-based electrode is dependent on the development of the edge or base surface of the pores formed on the surface of the carbon-based electrode, and in order to be a high-functional capacitor, the specific surface area of the carbon-based electrode and its The size of the pores formed on the surface should be optimized.

Activated carbon fiber is a fibrous activated carbon having a diameter of about 10 μm, and has a large specific surface area as well as a high adsorption and desorption rate to other materials. Although the activated carbon fiber has a high performance adsorbent and has the advantage of being easily molded into various forms, it is currently widely used industrially, and its use and amount of use, such as solvent recovery in the gas phase or air cleaning, are used. Compared to this activated carbon, very little situation.

The reason why the use and the amount of use of activated carbon fiber is very small as compared to activated carbon is because of the fact that activated carbon fiber is considerably higher than conventional activated carbon and the filling density of the fiber is very low. Although the average granular activated carbon filling density is about 0.5g / cc, the activated carbon fiber is only 0.2 ~ 0.3g / cc, so the activated carbon fiber is high performance on the basis of mass, compared to conventional activated carbon on the basis of volume. The disadvantage is that there is no particular advantage.

Therefore, in order to solve the shortcomings of the activated carbon fibers, a method of increasing the packing density of the activated carbon fibers by molding the activated carbon fibers using a binder such as pitch or phenol resin may be used. However, in the above method, when a large amount of binder is used to obtain a high density of activated carbon fibers, the binder blocks fine pores formed on the surface of the activated carbon fibers, and thus, the adsorption capacity of the activated carbon fibers can be lowered. There is a need for a technique that can produce activated carbon fibers without a binder.

In general, the carbon materials applied as electrode materials are mainly activated carbon and activated carbon fibers. In the case of powdered activated carbon, a binder is used as an electrode material, and in the case of activated carbon fibers, a packing state or a binder is used for filling density. It is applied to the electrode in the state which improved.

As an electrode material, activated carbon fibers are more effective than activated carbon, and activated carbon fibers are usually used in the form of fabrics, which are made of pitch fibers in the form of fabrics or webs by spinning carbon-based carbon fiber precursors as raw materials. Thereafter, it is carbonized under an inert atmosphere through an incompatibility process in air, and is produced by a method of forming fine pores in carbonized carbon fibers through liquid and gas phase activation.

T.Osaka et al. Prepared pellets by pressing activated carbon using an electrolyte as a binder in a press to make a composite electrode of pelletized activated carbon and an electrolyte and applied it as an electrode material of an electric double layer capacitor. When the specific surface area of the activated carbon was 1500 m ² / g, a storage capacity of 100 F / g was obtained.

K.Miura, H. Nakagawa, of Tokyo University, Japan, made a high-density carbon fiber disc by hot-molding after impregnating carbon fibers spun with a pitch-based carbon fiber precursor. The densified carbon fiber disks were activated with water vapor and KOH to convert them into densified activated carbon fiber disks, and the charge and discharge experiments were conducted using the same for the electrodes of the electric double layer capacitor. The disk showed a capacity of 40.8 F / g.

M.Endo et al., Of Shinshu University, Japan, added polyvinyliden chloride (PVDC), a polymer, to carbon materials and pressurized them to produce carbon disks, carbonizing and activating them as electrodes for electric double layer capacitors. In Japan, Kyushu University and Mitsubishi Gas research team attempted to increase the density by adding about 9 wt% of a novolac-type phenolic resin as a crosslinking agent to mesophase pitch.

As described above, most of the capacitor electrode material is activated by making carbon fiber excellent in formability while having high adsorption and desorption rate compared to an electrode or activated carbon made by integrating activated carbon in powder form with a binder in terms of efficiency. Activated carbon fiber is used.

However, when the binder is used as the impurity, the binder not only prevents the diffusion of the ions occurring in the electrode, but also prevents the fine pores formed in the activated carbon, thereby reducing the power storage efficiency. In order for the electrode of the capacitor to work effectively to express a high capacitance, the specific surface area of the activated carbon must be large, and as many pores as effective in adsorption and desorption of ions must be formed in the activated carbon.

Therefore, although activated carbon fiber is more preferable than activated carbon, in order to use the activated carbon fiber having better performance than activated carbon in the electrode, it is necessary to improve the low filling density peculiar to activated carbon fiber. Although it has been attempted, most of the methods have a problem of using a binder.

The present invention is to solve the problems encountered when using the activated carbon fiber as the electrode of the capacitor, to produce a pitch fiber by spinning a pitch-based carbon fiber precursor having excellent radioactivity, and then infusible and infusible The present invention provides a high-density activated carbon fiber disk and a method for producing the same, which are suitable for electrodes of a capacitor without the use of a binder that bonds carbon fibers by press-pushing the pitch fiber while raising the temperature in a mold and carbonizing and activating it under appropriate conditions. There is a purpose.

1 is a manufacturing process diagram of the densified activated carbon fiber disk for the ultra-high capacity capacitor electrode material of the present invention.

Figure 2 shows the structure of the densified carbon fiber disk produced by the method of the present invention observed with a scanning electron microscope,

(A) is the surface structure,

(B) is the cross-sectional structure,

(C) is the internal structure.

((Explanation of symbols for main part of drawing))

ACD. High Density Activated Carbon Fiber Disc CD. Densified Carbon Fiber Disc

NF. Incompatible Fiber NFD. Densified Infusible Fiber Disc

P. Pitch Carbon Fiber Precursor PF. Pitch fiber

The above object of the present invention is achieved by a series of processes for oxidative incompatibility, elevated temperature pressurization, carbonization, and activation of a fiber melted and spun with a pitch-based carbon fiber precursor having a softening point of 250 ° C. or higher.

The pitch-based carbon fiber precursor used as a base material of the densified activated carbon fiber disk for the ultra-high capacity capacitor electrode material of the present invention is manufactured by the method disclosed in Korean Patent Application No. 98-047218, which is a by-product of the naphtha decomposition process. It is an isotropic precursor with excellent melt spinning and oxidation insolubility and high carbonization yield, which is treated by adding alkyl group crosslinking agent to residue.

Looking at the manufacturing method of the present invention high density densified activated carbon fiber disk using the precursor in detail based on the process of Figure 1 as follows.

The production method of the present invention is to melt-spin the pitch-based carbon fiber precursor P having excellent spinning property having a softening point of 250 ° C. or higher at 280 to 350 ° C. at a pressure of ² to 10 kgf / cm ² (11) PF), the step of raising the melt-spun pitch fiber (PF) in air to oxidatively infusible (12) at 200 to 340 ° C for at least 1 hour to convert to infusible fibers (NF), and temperature control After charging the incompatible fiber (13) into a circular molder capable of heating, the temperature of the incompatible fiber (NF) introduced into the molder is raised and pressurized (14) at a pressure of 2 to 20 MPa in the range of 300 to 450 ° C. Making a densified carbon fiber disc (NFD) and carbonizing the fibrillated fiber disc (NFD) by maintaining it for at least 1 hour in an inert atmosphere at 950 to 1050 ° C. (15); Of water vapor / nitrogen at temperatures between 700 and 950 The step of activating the densified carbon fiber disk (CD) for 30 to 120 minutes (16) with water vapor having a ratio of 0.3 to 0.5 is carried out to convert to the final densified activated carbon fiber disk (ACD).

The most important process in the manufacturing process is the temperature pressurization in the molder, when the pressing pressure is less than 2MPa, it is difficult to form the disk, if the excess exceeds 20MPa infusible fibers will rupture. In addition, the step of making the densified incombustible fiber disk by heating and pressurizing, in addition to the method of pressurizing after raising the temperature as described above, the temperature and pressing force from the initial state to the final elevated temperature and the pressing force are roughly equally divided into four steps or less and stepwise. It is also possible to apply a method, in which case the workability is lowered if it exceeds four steps, which is not preferable.

That is, when the final elevated temperature and the pressing force are 400 ° C. and 20 MPa, the pressure may be applied while sequentially raising the temperature by applying a pressure of 5 MPa at 100 ° C., 10 MPa at 200 ° C., 15 MPa at 300 ° C., and 20 MPa at 400 ° C.

In addition, the densified activated carbon fiber disk of the present invention produced by the above method is composed of carbon fiber only without a binder, the filling density of the carbon fiber is 0.2 to 1.5 g / cc, the amount and the pressure imparted to the impregnated fiber charged in the molder By controlling the characteristics of the filling density can be easily changed.

The densified activated carbon fiber disks are carbonized in an inert atmosphere and activated by water vapor. The activated carbon fibers constituting the densified activated carbon fiber disks contain a large amount of fine pores. It is formed, and the filling density is high without a binder, and it is suitable for a capacitor electrode.

The purpose and detailed technical features and operational effects of the present invention will be clearly understood by the following detailed description with reference to the drawings showing preferred embodiments of the present invention.

Precursor used as the raw material of the densified activated carbon fiber disk of the present invention is a nitrogen of 2 to 10 kgf / cm at a temperature of 280 to 350 ℃ using a spinning device having a nozzle diameter of 0.2 mm and a nozzle length ratio of 2 to the nozzle diameter Pitch fibers were prepared by winding at a speed of 300 to 1000 m / min while applying ² pressure.

The pitch fibers spun as described above are optically isotropic, and in order to prevent melting of the pitch fibers which may occur during subsequent high temperature heat treatment, the temperature is raised to 200 to 340 ° C. at a rate of 5 ° C. per minute in an air atmosphere, and then 2 Oxidation stabilization treatment was performed for the pitch fibers held for a time.

In order to produce a shape suitable for capacitor electrodes with high filling density, 0.2-1.0 g of oxidatively stabilized incompatible fiber was charged in a circular molder having a cross-sectional area of 5 cm ² to 10 cm ^{2 at} a rate of 5 to 10 ° C./min. It heated up to 300-450 degreeC and pressurized for 5 to 20 minutes by the pressure of 2-20 Mpa, and produced the densified infusible fiber disk of 0.2-1.5 g / cc of filling density.

The high-density infusible fiber disk was carbonized for at least 1 hour in an inert atmosphere at 1000 ° C. made of argon gas.

3 is an electron micrograph of the carbon fiber aggregates constituting the densified carbon fiber disk of the disk form having a high packing density that can be used for the capacitor electrode without using a binder, from which the carbon fiber is not melted You can see that it remains as is. In addition, the filling density of the densified carbon fiber disk can be changed by adjusting the amount of incompatible fiber charged into the molder and the pressure applied during pressurization.

The carbonized densified carbon fiber disk was raised to 700 to 950 ° C. at an elevated temperature rate of 10 ° C./min under an inert atmosphere using nitrogen gas, and then maintained for 30 to 120 minutes, and the steam / nitrogen ratio was 0.4 during constant temperature maintenance. The disk is activated with water vapor by adjusting to. Fine pores are formed on the carbon fibers constituting the disk through activation, thereby producing a final densified activated carbon fiber disk that can be used as a capacitor electrode.

Looking at the embodiment to which the method of the present invention is applied and the comparative example not following the method of the present invention are as follows.

Example 1

A pitch-based carbon fiber precursor having a softening point of 265 ° C. was spun to prepare pitch fibers having an average fiber diameter of 12 μm. At this time, spinning was performed using a nozzle made of SUS 304 with a diameter of 0.2 mm and L / D (nozzle length / nozzle diameter) 2.0, spinning conditions of 295 ℃, spinning nitrogen pressure of 8kgf / cm ² , winding speed of 710m / min And the discharge amount of the melt pitch was maintained at 7.5 g / hr.

The spun pitch fiber was heated to 280 ° C. at a rate of temperature increase of 2 ° C./min, and then maintained for 2 hours to perform oxidation incompatibility. High-density incombustible fiber discs, in which 0.5 g of infusibilized pitch fibers, i.e., infusible fibers, are uniformly loaded in a mold of 5 cm ² and then heated up to 400 ° C. at a rate of 10 ° C./min and maintained for 10 minutes under a pressure of 10 MPa. Was prepared. In this case, the disk had a packing density of 0.83 g / cc and a thickness of 0.98 mm.

The high-density incombustible fiber disk was carbonized while maintaining the temperature after raising the temperature to 1000 ° C. at a rate of 10 ° C./min, wherein the carbonization yield was 75.5%, the filling density of the carbonized disc was 0.62 g / cc, and the thickness was 0.97. mm.

The carbonized disk was placed in a horizontal furnace, and then heated to 850 ° C. at a rate of 10 ° C./min, and activated by water vapor for 40 minutes at a ratio of water vapor / nitrogen of 0.4 to prepare disk 1. At this time, the disk 1 was burned off by oxidizing about 20% by water vapor, and the activation yield was 80%. The filling density of the disk 1 was 0.52 g / cc, the thickness was 0.96 mm, the specific surface area. Was 877 m ² / g.

The burn-off means that the weight is reduced by oxidation by water vapor, and the fine pores generated in the carbon fiber by activation increase the specific surface area of the carbon fiber. The specific surface area was calculated based on the BET equation after degassing the activated disk and determining the adsorption and desorption isotherms of nitrogen at 77 K using a Micromeritics device (Micromeritics ASAP 2010).

Example 2

In the same manner as in Example 1, 0.5 g was uniformly charged into a 5 cm ² molder after spinning and infusible fibers, and then heated at 400 ° C. at a rate of 10 ° C./min at 2 MPa and 200 ° C. The densified disk was made by holding at 4 MPa, 6 MPa at 300 ° C., and 8 MPa at 400 ° C. for 10 minutes.

While increasing the temperature as in the second embodiment, pressurized and maintained at an intermediate temperature, and pressurized and maintained at the final temperature, a densified disk can be manufactured as in Example 1, which is pressurized and maintained after reaching the final temperature. The filling density of the disk was 0.84 g / cc and the thickness was 1.02 mm.

The disc was carbonized in the same manner as in Example 1, where the carbonization yield was 79.5%, the filling density of the carbonized disc was 0.77 g / cc, and the thickness was 0.89 mm. The carbonized disk was placed in a horizontal furnace, and then heated to 900 ° C. at a rate of 10 ° C./min, and steam 2 was activated for 30 minutes using a steam / nitrogen ratio of 0.4, whereby disc 2 was produced. 2, about 40% was oxidized by water vapor, burned off, and the activation yield was 60%. The filling density of disk 1 was 0.52 g / cc and the thickness was 0.96 mm. And the specific surface area of the disk 2 was 1319 m <^2> / g.

Example 3

In the same manner as in Example 1, 0.5 g was uniformly charged into a 5 cm ² moulder after spinning and infusible fibers, and then heated up to 400 ° C. at a rate of 10 ° C./min for 10 minutes under a pressure of 8 MPa. Retention to produce a densified, incompatible fiber disk. At this time, the packing density of the prepared high-density incombustible fiber disk was 0.92 g / cc and the thickness was 0.97 mm. Carbonization was carried out in the same manner as in Example 1, where the carbonization yield was 79.3%, the filling density of the disk was 0.74 g / cc, and the thickness was 0.96 mm.

The carbonized disk was placed in a horizontal furnace, and then heated to 900 ° C. at a rate of 10 ° C./min and activated by water vapor for 60 minutes at a ratio of water vapor / nitrogen of 0.4. As for 3, about 67% of the oxidized water was burned off and burned off. The activation yield was 33%, and the filling density was 0.27 g / cc and the thickness was 0.92 mm. And the specific surface area of the disk 2 was 1642m <^2> / g.

Example 4

After spinning in the same manner as in Example 1 and impregnated and pressurized to prepare a densified incompatible fiber disk with a filling density of 0.83g / cc, thickness 1.04mm, which was carbonized in the same manner as in Example 1, The carbon yield was 75%, the filling density of the disk was 0.64 g / cc, and the thickness was 1.01 mm.

The carbonized disk was placed in a horizontal furnace, and then heated to 850 ° C. at a rate of 10 ° C./min, and activated by water vapor for 90 minutes at a ratio of water vapor / nitrogen of 0.4. The activation yield of disk 4 was 52%, filling density was 0.4 g / cc, and thickness was 0.84 mm.

Disc 5 was manufactured in the same manner as in the production of disc 4, except that the charging amount of the molder was 0.55 g. The filling density of the disk made by the molder press, which is the intermediate process of disk 5, was 0.84 g / cc and 1.05 mm thick. 1.04 mm, the activation yield of final disc 5 was 52%, filling density was 0.42 g / cc, and thickness was 0.89 mm.

Unit cells were prepared using the disks 4 and 5 as capacitor electrodes, and a charge and discharge experiment was conducted. 7.5 mol KOH mixture solution was used as electrolyte and charged to 0.9V with constant current 10mA / cm ² , maintained for 10 minutes, and discharged at 1-50mA / cm ² . A storage capacity of ³⁰ F / cm ³ is shown.

Example 5

Disc 6 was manufactured under the same manufacturing conditions as in Example 4, except that the molder loading amount was 0.3 g and the activation holding time was 60 minutes. Was 0.73g / cc, and the thickness was 0.75mm. The carbonization yield of the disc after carbonization was 70.1%, the filling density was 0.55g / cc, and the thickness was 0.72mm. g / cc, thickness was 0.68 mm.

Another disk 7 was manufactured under the same conditions as the disk 6, and the filling density of the disk produced by the molder press, which is the intermediate process of the disk 7, was 0.68 g / cc and the thickness was 0.80 mm, and the carbonization yield of the disk after carbonization was 73.1. %, Filling density was 0.5g / cc, thickness was 0.79mm, the activation yield of final disc 7 was 70%, filling density was 0.37g / cc, thickness was 0.77mm.

After manufacturing the unit cell using the disks 6 and 7 as the capacitor electrode, the electrical properties through the charge and discharge in the same manner as in Example 4 as a result of the non-capacitor of 125 ~ 130F / g and 30 ~ 35F / cm ³ The dose is shown.

Example 6

The activation temperatures and times were set at 800 ° C. × 120 minutes and 900 ° C. × 30 minutes, respectively.

The filling density of the disk made by the molder press, which is the intermediate process of the disk 8, was 0.85 g / cc and the thickness was 1.05 mm.The carbonization yield of the disk after carbonization was 74.4%, the filling density was 0.64 g / cc, and the thickness was 1.04 mm. The final disk 8 had an activation yield of 79%, a packing density of 0.49 g / cc, and a thickness of 1.02 mm.

The filling density of the disc produced by the molder press, which is the intermediate process of disc 9, was 0.82 g / cc and the thickness was 1.07 mm.The carbonization yield of the disc after carbonization was 79.2%, the filling density was 0.71 g / cc, and the thickness was 0.98 mm. The final disk 9 had an activation yield of 81%, a filling density of 0.59 g / cc, and a thickness of 0.96 mm.

After the unit cells were manufactured using the disks 8 and 9 as the capacitor electrodes, the electrical properties through the charging and discharging were examined in the same manner as in Example 4, and as a result, specific storage capacity of 93-100 F / g and 27-30 F / cm ³ was obtained. The dose is shown.

Working conditions of Examples 1 to 6 and physical properties of the disk are summarized in Tables 1 and 2 below.

division Example One 2 3 4 5 7 disk One 2 3 4 5 6 7 8 9 Radiation conditions Nozzle Diameter 0.2mm, Temperature 295 ℃, Nitrogen Pressure 8kgf / cm ² , Discharge Capacity 7.5g / hr, Yarn Fiber Diameter 12 μm Incompatibilities Temperature rise rate 2 ° C./min. Condition 280 ℃ × 2 hours Molder Pressure Temperature rise rate 10 ° C./min. Temperature 400 ℃ Condition 400 ° C × 10MPa × 10 minutes 100 ℃ × 2MPa, 200 ℃ × 4MPa, 300 ℃ × 6MPa, 400 ℃ × 10MPa × 10 minutes 400 ° C × 8MPa × 10 minutes 400 ° C × 10MPa × 10 minutes Charge 0.5g 0.55 g 0.3 g 0.5g carbonization Temperature rise rate 10 ° C./min. Temperature 1000 ℃ time 1 hours Activation Temperature rise rate 10 ° C./min. The ratio of water vapor nitrogen 0.4 Temperature 850 ℃ 900 ℃ 850 ℃ 800 ℃ 900 ℃ time 40 minutes 30 minutes 60 minutes 90 minutes 60 minutes 120 minutes 30 minutes

division Example One 2 3 4 5 6 disk One 2 3 4 5 6 7 8 9 Molder Pressure Packing density 0.83 0.84 0.92 0.83 0.84 0.73 0.68 0.85 0.82 thickness 0.98 1.02 0.97 1.04 1.05 0.75 0.80 1.05 1.07 carbonization yield 75.5 79.5 79.3 75.0 80.4 70.1 73.1 74.4 79.2 Packing density 0.62 0.77 0.74 0.64 0.68 0.55 0.50 0.64 0.71 thickness 0.97 0.89 0.96 1.01 1.04 0.72 0.79 1.04 0.98 Activation yield 80 60 33 52 52 73 70 79 81 Packing density 0.52 0.49 0.27 0.40 0.42 0.40 0.37 0.49 0.59 thickness 0.96 0.86 0.92 0.84 0.89 0.68 0.77 1.02 0.96 Specific surface area 877 1319 1642

* Fill Density: Disk weight divided by disk volume (g / cc).

* Carbonization yield: The weight of the sample after carbonization divided by the weight of the sample before carbonization

percentage(%).

* Activation yield: weight of disk after activation by weight of disk before activation

Percent divided by%.

* Thickness (mm), specific surface area (m ² / g)

Comparative Example 1

After spinning in the same manner as in Example 1 and not undergoing an incompatibility process, the densified fiber disk was first prepared by charging and pressing into a molder in the same manner as in Example 1, and thus, an unstable disc was prepared as the incompatibility was omitted. .

The disc was infused under the same conditions as in Example 1, but heat deformation occurred in the fiber of the disc that had not been subjected to the incompatibility, and the incomplete was incomplete. The temperature was raised to 1000 ° C. at a rate of 10 ° C./min and carbonized for 1 hour, resulting in a low carbon yield of 30%.

Comparative Example 2

The resultant carbonization was carried out under the same conditions as in Example 1 and carbonized under the same conditions as in Example 1 without mold pressurization, and the carbonization yield was 74.3%.

The carbonized carbon fiber was activated under the activation condition of Disc 6, and the activation yield was 44%. 0.3 g of this activated carbon fiber was charged into a 10 cm ² molder and the temperature was raised to 400 ° C. at a rate of 10 ° C./min and maintained for 10 minutes under a pressure of 10 MPa. However, the activated carbon fiber was destroyed and no activated carbon fiber disc was formed. .

Comparative Example 3

In order to compare the performance when the densified activated carbon fiber disk according to the method of the present invention is used as a capacitor electrode, a unit cell using a commercially available activated carbon fiber fabric as a capacitor electrode was prepared for charge and discharge experiments. Was carried out.

The thickness of the activated carbon fiber fabric used in the experiment was 0.51 mm, and the specific surface area was 1500 m ² / g. As a result of examining the electrical characteristics through the charge and discharge in the same manner as in Example 4, it showed a specific capacitance of 126F / g and 19.6F / cm ³ .

In the case of the electrical property test, the end voltage at the time of discharge was 0.1V, and the calculation of the storage capacity was calculated by the following equation 1 from the change of the discharge voltage according to the discharge time, and from the result, the storage capacity per unit weight and unit volume The storage capacity was calculated.

In the above formula, C is the capacitance, I is the discharge current, Δt is the change in the discharge time, ΔV is the change in voltage according to the discharge time, the summary of the capacitor capacity of the test examples and comparative examples are shown in Table 3.

division Example 4 Example 5 Example 6 Comparative Example 3 Disk 4 Disk 5 Disk6 Disc7 Disk8 Disk 9 textile Thickness (mm) 0.84 0.89 0.68 0.77 1.02 0.96 0.51 Capacitor Capacity F / g 140-150 125-130 93-100 126 F / cm ² 25-30 30 to 35 27-30 19.6

It can be seen from Table 3 that the densified activated carbon fiber disk according to the present invention has a storage capacity per unit weight similar to that of the conventional activated carbon fiber fabric, but the storage capacity per unit volume is remarkably improved as the density increases.

As described above, the method of manufacturing the densified activated carbon fiber disk for the ultra-high capacity capacitor electrode material according to the present invention is capable of densifying carbon fibers even without a binder, and thus, fine pores generated in the carbon fibers through an activation process. It is possible to maximize the specific surface area to the same weight by preventing the insolubilization by this binder.

Therefore, the densified activated carbon fiber disk produced by the method of the present invention can be used not only as a capacitor electrode but also as a high functional carbon fiber material such as an adsorbent, and can reduce the manufacturing cost of the carbon fiber material because it uses a relatively inexpensive raw material. There is an advantage.

Claims (3)

After melt-spinning the pitch-based carbon fiber precursor at 280-350 ° C., it is prepared by the oxidation incompatibilization treatment of claim 2, pressurization, carbonization, and activation treatment by a molder. High density capacitive activated carbon fiber disk for ultra-high capacity capacitor electrode material characterized by having a packing density. Making a pitch fiber (PF) by melt spinning the pitch-based carbon fiber precursor (P) having a softening point having a softening point of 250 ° C. or higher at 280 to 350 ° C. at a pressure of ² to 10 kgf / cm ² (11); The molten spun pitch fiber (PF) is heated in air and subjected to oxidative incompatibility treatment (12) at 200 to 340 ° C. for at least 1 hour to be converted into incompatible fiber (NF), and the fire is heated in a circular molder. After charging the fused fiber (13), the temperature of the incompatible fiber (NF) introduced into the molder was raised to pressurizing (14) at a pressure of 2 to 20 MPa in the range of 300 to 450 ° C. to make a high density incompatible fiber disk (NFD). And carbonizing (15) the densified carbon fiber disk (CD) while maintaining the densified infusible fiber disk (NFD) for at least 1 hour in an inert atmosphere of 950 to 1050 ° C, and at a temperature of 700 to 950 ° C. Water vapor with a water vapor / nitrogen ratio of 0.3 to 0.5 Activating the densified carbon fiber disk (CD) for 30 to 120 minutes (16) and converting it into a final densified activated carbon fiber disk (ACD). Making a pitch fiber (PF) by melt spinning the pitch-based carbon fiber precursor (P) having a softening point having a softening point of 250 ° C. or higher at 280 to 350 ° C. at a pressure of ² to 10 kgf / cm ² (11); The molten spun pitch fiber (PF) is heated in air and subjected to oxidative incompatibility treatment (12) at 200 to 340 ° C. for at least 1 hour to be converted into incompatible fiber (NF), and the fire is heated in a circular molder. After charging the fused fiber (13), the final elevated temperature of the incompatible fiber charged into the molder was 300 to 450 ° C. and the final applied pressure was 2 to 20 MPa, and the range from the initial state to the final temperature and the applied pressure was 4 steps or less. Roughly evenly dividing and applying the elevated temperature and pressing force stepwise to make a densified incompatible fiber disk (NFD), and maintaining the densified incompatible fiber disk (NFD) for at least one hour in an inert atmosphere at 950 to 1050 ° C. (15) making the densified carbon fiber disc (CD) and activating the densified carbon fiber disc (CD) for 30 to 120 minutes with steam having a water vapor / nitrogen ratio of 0.3 to 0.5 at a temperature of 700 to 950 ° C. 16) A densified activated carbon fiber disk for an ultra high capacity capacitor electrode material, characterized by the step of converting to a final densified activated carbon fiber disk (ACD).