KR20080056794A - Electrode for electric double layer capacitor and method of fabrication the same - Google Patents

Abstract

An electrode for an electric double layer capacitor and a method for fabricating the same are provided to increase an electrode density and to reduce a contact resistance by performing a compressing process when a conducting paste is fixed on an electric collector. An electrode for an electric double layer capacitor includes a powder activated carbon, a binder, and a poly-N-vinylpyrrolidone. The powder activated carbon is composed of a coconut shell series activated carbon of 5-30% having a non-surface area of 1500-1700/g, a phenol resin series activated carbon of 5-30weight% having a non-surface area of 2000-2500/g, and a phenol resin series activated carbon of 10-50weight% having a non-surface area of 2500-3500/g. The binder is composed of a poly-tetrafluoroethylene of 1-5weight%, and a carboxymethylcelluose of 0.2-5weight%. The poly-N-vinylpyrrolidone is a dispersion catalyst of the carboxymethylcellulose. An electric composition is acquired by mixing a conducting additive of a carbon fiber or a carbon tube of 5-30weight%. A conducting paste acquired by mixing the electric composition with a dispersion medium, is coated and fixed on a metal electric collector.

Description

Electrode for Electric Double Layer capacitor and Method of Fabrication the Same}

1 is a perspective view showing a mesh foil of a network structure showing a metal current collector used in the present invention.

Figure 2 shows a metal current collector used in the present invention, the surface photograph showing the etching foil formed with grooves.

3 is a perspective view illustrating a process of coating an electrode on an etching foil in which grooves are formed, showing a metal current collector used in the present invention.

Figure 4 is a perspective view showing a step of bonding the electrode for an electric double layer capacitor according to the present invention to the case.

Figure 5 is a partially exploded cross-sectional perspective view showing a coin-type electric double layer capacitor applied electrode for an electric double layer capacitor according to the present invention.

6 is a partially exploded cross-sectional perspective view showing a wound type electric double layer capacitor to which an electrode for an electric double layer capacitor according to the present invention is applied.

<Code Description of Main Parts of Drawing>

1: negative electrode 1 ': positive electrode

1a: negative electrode body 1b: negative electrode current collector

1c: positive electrode body 1d: positive electrode current collector

1e: etching groove 2: case

2a: cathode case 2b: anode case

3: gasket 4: separator

5: tube 6: terminal

6a: negative terminal 6b: positive terminal

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrode for an electric double layer capacitor and a method of manufacturing the same, and more particularly, three types of carbon activated carbon having different specific surface areas, PTFE, CMC as a binder, PVP as a dispersion catalyst, and additives (improving materials). An electrode for an electric double layer capacitor obtained by slurrying an electrode composition obtained by mixing a carbon fiber or a carbon tube forming a nanostructure in an appropriate ratio with a dispersion medium to have a predetermined viscosity, and then fixing the electrode composition to a metal current collector and a method of manufacturing the same will be.

An electric double layer capacitor is capable of only two electrodes (polarized electrodes, 1 and 1 ') of the positive and negative electrodes, and a separator made of a porous material (electrolyte), which allows only ion conduction between these two electrodes and prevents insulation and short circuit. It consists of a gasket to prevent leakage of electrolyte, insulation and short circuit protection, and a metal outer case that wraps these components. The separator is separated by a separator to apply electric charge to two opposite electrodes so that electrolyte ions The potential difference produced | generated by forming an electric double layer in the electrode surface which has is used.

In general, the electrode of the electric double layer capacitor is formed with a large number of fine pores (pore) to increase the resistance by the activated carbon having a high specific surface area and high electrical conductivity, a binder for bonding the activated carbon particles, and an insulating material binder In order to prevent or compensate for conductivity, the conductive additives are mixed to a certain ratio to obtain an electrode composition, and the electrode composition is mixed with a dispersion medium to form a slurry, which is then sheeted or a metal current collector such as aluminum foil. The electrode of the form coated on the surface is used a lot.

Conventionally, in forming the electrode composition for an electric double layer capacitor, 30-40 weight of coconut shell carbon activated carbon (specific surface area 1,500-1,700 / g) and phenol resin-based carbon activated carbon (specific surface area 2000-2,500 / g), respectively. %, 5-10% by weight of polyvinylidene-fluoride (PVDF) or polytetrafluoroethylene (PTFE) as a binder, and carbon black as a conductive additive (modifier) 10 to 30% by weight of the mixed composition, and the electrode composition is slurried with a dispersion medium N-methyl-2-pyrrolidone (NMP; N-methyl-2-pyrrolidone) or the like and sheeted directly, or on a metal current collector It was prepared by coating and fixing on. However, such an electrode composition is conventionally limited to carbon having excellent electrical conductivity with a specific surface area of 50 / g or less such as carbon black, and the prepared electrode composition has low electrical conductivity and a narrow range of specific surface area. It is limited, and as it has a low capacitance, it is not easy to manufacture a high capacitance electrode. That is, due to the performance limited only to the role of the conductivity improver for improving the electrical conductivity, only a means for increasing the volume of the manufactured electrode was able to obtain an activated carbon-based polarizable electrode having high capacity characteristics. In addition, the slurry of the electrode composition has a problem in that the bonding strength with each material during the electrode manufacturing process is weak according to the shape characteristics of the spherical or granular carbon black, so that a crack occurs during high temperature drying. .

Accordingly, the present invention has been made in order to solve the above problems, and in forming an electrode composition of an electric double layer capacitor, three kinds of carbon activated carbon having different specific surface areas, PTFE and CMC having high viscosity as binders are used. And adding PVP as a dispersion catalyst for enhancing the dispersibility of the CMC, and adding carbon fiber or carbon tube forming a nanostructure exhibiting a high specific conductivity at the same time as a specific specific surface area and adding the composition at an appropriate ratio. The conductive paste slurried by the dispersion medium has a wider specific surface area distribution, high bonding force, and high electrical conductivity, so that the thickness can be easily adjusted when coating on the metal current collector, the capacitance can be designed, and the excellent electrical performance is achieved. It is to provide an electrode for an electric double layer capacitor having and a method of manufacturing the same.

The present invention is 5 to 30% by weight of coconut shell carbon activated carbon having a specific surface area of 1,500 to 1,700 / g, 5 to 30% by weight of phenol resin based activated carbon having a specific surface area of 2,000 to 2,500 / g, and a specific surface area of 2,500. 10-50% by weight of powdered activated carbon of phenol resin-based activated carbon of 3,500 / g;

1 to 5% by weight of polytetrafluoroethylene (PTFE; poly-tetrafluoroethylene) and 0.2 to 5% by weight of carboxymethylcellulose (CMC);

0.2-5% by weight of poly-N-vinylpyrrolidone (PVP) as a dispersion catalyst of the CMC;

Electrode composition obtained by mixing 5-30% by weight of an additive (improving material) of carbon fiber or carbon tube forming a nanostructure is mixed with a dispersion medium to slurry to obtain an appropriate viscosity to obtain a conductive paste, which is applied to a metal current collector. The present invention provides a coated and fixed electrode for an electric double layer capacitor and a method of manufacturing the same.

According to the present invention, the viscosity of the conductive paste by the electrode composition may have a high viscosity with a wide viscosity distribution in the range of 500 to 50,000 cps. Accordingly, it is possible to control the thickness of the electrode when coating on the metal current collector, the electrode density is increased by the high viscosity has a high capacitance. In addition, since the thickness can be adjusted, the capacitance can be arbitrarily adjusted. In addition, water (distilled water) may also be used as a dispersion medium, including organic solvents such as NMP (N-methyl-2-pyrrolidone), which are commonly used.

Hereinafter, with reference to the accompanying drawings will be described in detail the present invention.

In the present invention, when applying powdered activated carbon having a large specific surface area and high electrical conductivity as an electrode material to an electrode material, a coconut shell-based carbonized activated carbon having a specific surface area of 1,500 to 1,700 / g and a specific surface area of 2,000 to 2,000 are used. Phenol resin based carbon activated carbon having 2,500 / g is used, and in addition, phenolic resin based carbon activated carbon having a specific surface area of 2,500 to 3,500 / g is introduced in order to have a high capacitance for oxidation according to the present invention.

According to the present invention, in forming three kinds of carbonized activated carbon having different specific surface areas, 5 to 30% by weight of coconut shell hydrocarbon activated carbon having a specific surface area of 1,500 to 1,700 / g relative to the total weight of the electrode composition. The specific surface area and pores of the activated carbon are obtained by appropriate composition of 5 to 30% by weight of phenolic resin activated carbon having a surface area of 2,000 to 2,500 / g, and 10 to 50% by weight of phenol resin based activated carbon having a specific surface area of 2,500 to 3,500 / g. The distribution of is increased and high capacity design of the electric double layer capacitor is possible. That is, in terms of volume density, which is one of the criteria for exposing the maximum capacity per unit volume of the electrode, the electrode volume density is increased by the ratio and method according to the present invention.

In addition, as a binder in the present invention, 1 to 5% by weight of polytetrafluoroethylene (PTFE) and 0.2 to 5% by weight of carboxymethylcellulose (CMC) are added to give high viscosity to the conductive paste. Used. In addition, in order to increase the dispersibility of the CMC having high viscosity, 0.2-5% by weight of poly-N-vinylpyrrolidone (PVP) is added as a dispersion catalyst of the CMC.

The conductivity improving agent used in the present invention is mixed with hematite (Fe ₂ O ₃ ) powder and alumina (Al ₂ O ₃ ) powder in a weight ratio of 1: 1 to a drum mixer and mixed for 3 hours, the mixed powder 10g alumina container In a box-type furnace, the furnace was kept at 1,300 for 2 hours in the air, and after cooling, the mass mixture was taken out of the furnace, and 0.3 g of a powder having a particle size of 100 or less was put into an alumina boat in a grinder, and a tubular furnace equipped with a quartz tube having a diameter of 60 was used. Heated to nitrogen up to 650 and replaced with a mixed gas of hydrogen 1l / min and ethylene 0.1l / min, followed by reduction and carbon deposition for 40 minutes, then replaced with nitrogen, cooled to room temperature, and then deposited with an average diameter of 10-50 screwing the Fe ₂ O ₃ -MgO as empty daerong shape of carbon tubes that form the nanostructures, or the same method 1: If using a 1, Fe ₂ O ₃ : Fe ₂ O ₃ when SiO ₂ is used as 1: 1. : SiO ₂ : Fe ₂ O ₃ when MgO is used at 1: 0.5: 0.5 : SiO ₂ : When MgO: Al ₂ O ₃ is used as 1: 0.5: 0.5: 0.5, when NiO: MgO is used as 1: 1 and when CoO: SiO ₂ is used as 1: 1, Fe ₂ O ₃ : When NiO: Al ₂ O ₃ is used as 1: 1: 1, and Fe ₂ O ₃ : NiO: CoO: Al ₂ O ₃ : SiO ₂ : Carbon tube having a nanostructure having an average diameter of 10 to 50 by preparing a catalyst when MgO is used as 1: 1: 1: 1: 1: 1: 1,

Alternatively, hematite (Fe ₂ O ₃ ) powder and nickel oxide (NiO) powder are mixed in a weight ratio of 1: 1, mixed in a drum mixer for 3 hours, and 10 g of the mixed powder is placed in an alumina container and 900 in the air in a box-type electric furnace. The mixture was sintered and cooled in a furnace for 2 hours, and the sintered mixture was taken out of the electric furnace and crushed by a pulverizer. 0.3 g of powder having an average particle size of 100 or less was placed in an alumina boat and heated to nitrogen up to 550 in a tubular furnace equipped with a quartz tube with a diameter of 60. Substitute 40 ml of mixed gas of 1l / min and 0.2l / min of ethylene, perform reduction and carbon deposition for 40 minutes, replace with nitrogen, cool to room temperature, and form a hollow nano structure with a solid average diameter of 200. Carbon fiber,

Alternatively, the nickel oxide (Fe ₂ O ₃ ) powder and the copper oxide (CuO) powder are mixed in a weight ratio of 7: 3, mixed in a drum mixer for 3 hours, and 10 g of the mixed powder is placed in an alumina container and stored in a box-type electric furnace at 1,000 in air. After 2 hours of cooling in a furnace, the sintered mixture was taken out of the electric furnace and crushed by a pulverizer. 0.3 g of powder having an average particle size of 100 was placed in an alumina boat, and heated to nitrogen up to 550 in a tubular furnace equipped with a 60-diameter quartz tube. Substituting a mixture gas of / min and acetylene 0.2l / min, reducing and carbon deposition reaction for 40 minutes, then replaced with nitrogen, cooled to room temperature and formed a hollow nanostructure with a solid diameter of 200 5 to 30% by weight of carbon fiber is used.

Conventional additives can be used alone or mixed with carbon black (pore) is not formed in the particles (pore) alone or mixed, but if carbon black is added independently to add a large amount to reduce the resistance, which is a blackout It causes a decrease in capacity. In addition, VGCF having excellent conductivity may be used alone, but in consideration of VGCF being expensive, it is preferable to use them by proper mixing. Therefore, when appropriately mixed with 5 to 30% by weight of carbon fiber or carbon tube forming nanostructures characterized by the above-described manufacturing process having a specific surface area is secured, high electrical conductivity and resistance reduction, etc. The effect can be obtained. The weight ratio expressed above is the weight% with respect to the total weight of an electrode composition.

The carbon fiber or carbon tube forming the nanostructure has pores formed therein, and has a fine pore structure with excellent electrical conductivity as compared with the conventional conductivity improving agent.

In addition, the electrode composition prepared as described above may be dispersed by water (distilled water) including an organic solvent such as NMP. In a preferred dispersion method, a small amount of the dispersion medium is added to the electrode composition, the viscosity is measured, and the slurry is slurried to have a predetermined viscosity to obtain a conductive paste.

According to the present invention, the composition of the electrode composition as described above has excellent electrical performance such as capacitance, internal resistance and leakage current required for the electric double layer capacitor, and the viscosity of the conductive paste obtained by slurrying with a dispersion medium is 500 to 50,000 cps. Can be adjusted to a wide range of. Accordingly, the thickness of the electrode when the coating on the metal current collector is possible. In addition, the electrode viscosity is increased by the high viscosity, and has a high capacitance. In addition, the thickness can be adjusted to increase the capacitance. In addition, the drying time is longer, productivity is reduced, and cracks are generated when drying at a high temperature, whereas using an electrode composition prepared by adding carbon fibers or carbon tubes forming a nanostructure according to the present invention is used. The drying time is shortened, and cracking does not occur even when dried at a high temperature.

The conductive paste is coated on a current collector in the form of a metal foil such as Al or Ni. Preferably, a coating is performed on a mesh foil of a network structure in which a plurality of voids are formed as shown in FIG. 1 or an etching foil in which grooves are formed on both upper and lower surfaces as shown in FIG. 2. However, the upper and lower sections or both surfaces are coated. That is, the conductive paste is laminated and coated on the upper surface to be sufficiently embedded in the pores or recesses formed in the current collector, and then dried, and the laminated and coated on the lower surface to dry. In the case of coating on the mesh foil, the conductive paste, which is an electrode material, is laminated and coated on the upper and lower end surfaces or both sides to increase the overall coating thickness, thereby increasing the capacitance of the electrode and eventually increasing the life of the capacitor. The laminated conductive paste layers are bonded to each other by the electrode material embedded in the voids, and the peeling phenomenon from the current collector of the electrode material is suppressed. In addition, in the case of coating on the etching foil, as the surface area of the current collector by the groove portion becomes wider, the contact area of the current collector and the conductive paste is increased, so that the electrical conductivity between the two components is improved and more firmly coupled.

Subsequently, the coated, dried section or both sides are pressed using a heating roll heated to a temperature of 100-250. As the pressing process is performed using the heated rolls as described above, the electrode material is sufficiently intimately adhered to the voids or recesses and is completely fixed to the current collector to be integrated. In addition, the carbonized activated carbon particles are in close contact with each other, resulting in intimate contact between the particles, and the contact resistance decreases as the density of the powdered activated carbon particles per unit volume increases. This, in turn, has the effect of reducing the internal resistance when considered as an electric double layer capacitor as a whole.

Hereinafter, it will be described in detail through a preferred embodiment of the present invention.

Example 1

20 parts by weight of coconut shell carbonized activated carbon having a specific surface area of 1,500 to 1,700 / g, 10 parts by weight of phenolic resin activated carbon having a specific surface area of 2,000 to 2,500 / g, and a phenolic resin activated carbon having a specific surface area of 2,500 to 3,500 / g 30 The weight part was put into a container, and 2 weight part of PTFE, 0.75 weight part of CMC, and 0.5 weight part of PVP were added here.

As the conductive additive, hematite (Fe ₂ O ₃ ) powder and alumina (Al ₂ O ₃ ) powder were mixed in a weight ratio of 1: 1 and placed in a drum mixer for 3 hours, and the mixed powder 10g was placed in an alumina container. After holding for 2 hours at 1,300 in the atmosphere in an electric furnace, and cooling down, the mass mixture was taken out of the electric furnace, and 0.3 g of powder having a particle size of 100 or less was put in an alumina boat by a pulverizer. After heating up and substituting with a mixed gas of hydrogen 1l / min and ethylene 0.1l / min, reducing and carbon deposition reaction for 40 minutes, replacing with nitrogen and cooling to room temperature 50 parts by weight of the carbon tube forming the nanostructure of was added to mix the electrode material. Then, a small amount of distilled water was added as a dispersion medium, and the mixture was stirred at low speed so as to form a slurry that can be coated, thereby obtaining a conductive paste. At this time, the viscosity was measured at the same time as stirring, distilled water was stopped when the viscosity of the conductive paste reached the range of about 8,000 ~ 10,000cps.

The conductive paste was laminated and coated on the upper surface of the aluminum mesh foil current collector using a coater, and dried in an oven at a high temperature of 130 to 180 for 1 to 3 hours. At this time, the occurrence of cracks was confirmed by an optical microscope (max 5000 times). The conductive paste was laminated and coated on the lower surface of the current collector, followed by drying. Then, a pressing process was performed in a roll press heated to 180 degrees.

The electrode foil thus prepared was taken to have a diameter of 10 and welded and bonded to the anode and the cathode case.

As shown in FIG. 3, the anode case is welded and the electrode electrode is welded and the electrode is sandwiched between the cathode and the electrode, and the cathode and the cathode are coupled to each other. A coin-type electric double layer capacitor was produced. In addition, the positive electrode, the negative electrode, and the electrolyte were impregnated with an organic electrolyte solution propylene carbonate tetra-etyl ammonium tetra-fluorobonate (concentration of 0.6 to 1.2 N).

The present inventors evaluated the capacitance, the leakage current and the internal resistance of the electric double layer capacitor constituted by the electrode according to the present invention as described above. In addition, the coating of the conductive paste on the metal current collector was evaluated for the occurrence of cracking with respect to the electrode subjected to the drying process by an optical microscope (max 5000 times). The results are shown in the following [Table 1].

Example 2

20 parts by weight of coconut shell carbonized activated carbon having a specific surface area of 1,500 to 1,700 / g, 10 parts by weight of phenolic resin activated carbon having a specific surface area of 2,000 to 2,500 / g, and a phenolic resin activated carbon having a specific surface area of 2,500 to 3,500 / g 30 The weight part was put into a container, and 2 weight part of PTFE, 0.75 weight part of CMC, and 0.5 weight part of PVP were added here.

As the conductive additive, hematite (Fe ₂ O ₃ ) powder and nickel oxide (NiO) powder were mixed in a weight ratio of 1: 1, and then mixed in a drum mixer for 3 hours, and 10 g of the mixed powder was put in an alumina container in a box-type electric furnace. The mixture was sintered in an air furnace at 900 for 2 hours, sintered, and the sintered mixture was taken out of the electric furnace and crushed by a crusher. Substituted with a mixed gas of hydrogen 1l / min and ethylene 0.2l / min, reduced for 40 minutes and carbon deposition reaction, and then replaced with nitrogen, cooled to room temperature, and the solid nanostructure of the solid shape of the average diameter 200 deposited 50 parts by weight of the carbon fibers forming was added to mix the electrode materials.

Then, a small amount of distilled water was added as a dispersion medium, and the mixture was stirred at low speed so as to form a slurry that can be coated, thereby obtaining a conductive paste. At this time, the viscosity was measured at the same time as stirring, distilled water was stopped when the viscosity of the conductive paste reached the range of about 8,000 ~ 10,000cps.

The conductive paste was laminated and coated on the upper surface of the aluminum mesh foil current collector using a coater, and dried in an oven at a high temperature of 130 to 180 for 1 to 3 hours. At this time, cracking was confirmed by an optical microscope (max 5000 times). The conductive paste was laminated and coated on the lower surface of the current collector, followed by drying. Then, a pressing process was performed in a roll press heated to 180 degrees.

The electrode foil thus prepared was taken to have a diameter of 10 and welded and bonded to the anode and the cathode case.

As shown in FIG. 3, the anode case is welded and the electrode electrode is welded and the electrode is sandwiched between the cathode and the electrode, and the cathode and the cathode are coupled to each other. A coin-type electric double layer capacitor was produced. In addition, the positive electrode, the negative electrode, and the electrolyte were impregnated with an organic electrolyte solution propylene carbonate tetra-etyl ammonium tetra-fluorobonate (concentration of 0.6 to 1.2 N).

The present inventors evaluated the capacitance, the leakage current and the internal resistance of the electric double layer capacitor constituted by the electrode according to the present invention as described above. In addition, the coating of the conductive paste on the metal current collector was evaluated for the occurrence of cracking with respect to the electrode subjected to the drying process by an optical microscope (max 5000 times). The results are shown in the following [Table 1].

Example 3

20 parts by weight of coconut shell carbonized activated carbon having a specific surface area of 1,500 to 1,700 / g, 10 parts by weight of phenolic resin activated carbon having a specific surface area of 2,000 to 2,500 / g, and a phenolic resin activated carbon having a specific surface area of 2,500 to 3,500 / g 30 The weight part was put into a container, and 2 weight part of PTFE, 0.75 weight part of CMC, and 0.5 weight part of PVP were added here.

As the conductive additive, nickel oxide (Fe ₂ O ₃ ) powder and copper oxide (CuO) powder were mixed in a weight ratio of 7: 3, mixed in a drum mixer for 3 hours, and 10 g of the mixed powder was put in an alumina container in a box-type electric furnace. Maintained at 1,000 to 2 hours in the air and cooled in a furnace, the sintered mixture was taken out of the electric furnace and crushed by a pulverizer, and 0.3g of powder having an average particle size of 100 was placed in an alumina boat and heated to nitrogen up to 550 in a tubular furnace equipped with a 60-diameter quartz tube. After replacing with a mixed gas of hydrogen 1l / min and acetylene 0.2l / min and reducing and carbon deposition reaction for 40 minutes, and then replaced with nitrogen and cooled to room temperature, the solid nanostructure of a solid diameter of 200 is deposited 50 parts by weight of the formed carbon fibers were added to mix the electrode materials.

Then, a small amount of distilled water was added as a dispersion medium, and the mixture was stirred at low speed so as to form a slurry that can be coated, thereby obtaining a conductive paste. At this time, the viscosity was measured at the same time as stirring, distilled water was stopped when the viscosity of the conductive paste reached the range of about 8,000 ~ 10,000cps.

The conductive paste was laminated and coated on the upper surface of the aluminum mesh foil current collector using a coater, and dried in an oven at a high temperature of 130 to 180 for 1 to 3 hours. At this time, the occurrence of cracks was confirmed by an optical microscope (max 5000 times). The conductive paste was further laminated and coated on the lower surface of the current collector, followed by drying. Then, a pressing process was performed in a roll press heated to 180 degrees.

The electrode foil thus prepared was taken to have a diameter of 10 and welded and bonded to the anode and the cathode case.

As shown in FIG. 3, the anode case is welded and the electrode electrode is welded and the electrode is sandwiched between the cathode and the electrode, and the cathode and the cathode are coupled to each other. A coin-type electric double layer capacitor was produced. In addition, the positive electrode, the negative electrode, and the electrolyte were impregnated with an organic electrolyte solution propylene carbonate tetra-etyl ammonium tetra-fluorobonate (concentration of 0.6 to 1.2 N).

The present inventors evaluated the capacitance, the leakage current and the internal resistance of the electric double layer capacitor constituted by the electrode according to the present invention as described above. In addition, the coating of the conductive paste on the metal current collector was evaluated for the occurrence of cracking with respect to the electrode subjected to the drying process by an optical microscope (max 5000 times). The results are shown in the following [Table 1].

Comparative Example 1

40 parts by weight of coconut shell carbonized activated carbon having a specific surface area of 1,500 to 1,700 / g, and 30 parts by weight of phenol resin carbonized activated carbon having a specific surface area of 2,000 to 2,500 / g were placed in a container, and 10 parts by weight of PVDF and nanostructures were formed therein. 20 parts by weight of the carbon fiber or carbon tube was added to mix the electrode materials. And it stirred at low speed, adding small amount NMP as a dispersion medium until it became the slurry state which can be coated. In addition, the viscosity was measured at the same time as the stirring, the viscosity was evaluated as low as about 2,500cps when the slurry was coatable.

The slurry obtained as described above was coated, dried, and pressed in the same manner as in Example 1 to prepare an electrode. This was applied to the coin-type electric double layer capacitor as shown in FIG. Then, in the same manner as in Example 1, the capacitance, leakage current and internal resistance, and whether the crack was generated for the electrode subjected to the drying process was evaluated. The results are shown in the following [Table 1].

TABLE 1

Remarks Capacitance (F) (at discharge current / 1mA) Leakage Current Internal resistance Cracks Example 1 1.7 10 3 none Example 2 1.9 12 4 none Example 3 2.0 10 2 none Comparative Example 1 0.9 90 9 has exist

As can be seen in Table 1, it can be seen that the electric double layer capacitor to which the electrode according to the present invention is applied shows excellent electrical characteristics in capacitance, leakage current and internal resistance. Due to the excellent electrode density and electrical conductivity, there is a characteristic of reducing the leakage current, which is expected to exhibit high charging efficiency soon. In addition, it can be seen that cracking does not occur even when dried at a high temperature.

As described above, the present invention can ensure excellent electrical performance such as capacitance, internal resistance, leakage current, and the like required for the electric double layer capacitor. Accordingly, the thickness of the electrode can be easily controlled by the characteristics of the conductive additive of the nanostructure when coating on the metal current collector, and the electrode density is increased by the high viscosity to have a high capacitance. In addition, the thickness can be adjusted to arbitrarily adjust the capacitance.

In addition, the present invention does not generate cracks even when dried at a high temperature. In addition, when the conductive paste is adhered to the current collector, a pressing process is performed to increase the electrode density of the electrode material, thereby reducing the contact resistance, thereby reducing the internal resistance of the electric double layer capacitor.

Claims (9)

In the electrode for an electric double layer capacitor formed by coating a conductive paste obtained by mixing a coconut shell-based activated carbon, phenol resin-based activated carbon, a binder, a conductive additive and a dispersion medium on a metal current collector, 5 to 30% by weight of coconut shell carbon activated carbon having a specific surface area of 1,500 to 1,700 / g, 5 to 30% by weight of phenol resin based activated carbon having a specific surface area of 2,000 to 2,500 / g, and a specific surface area of 2,500 to 3,500 / g 10 to 50% by weight of powdered activated carbon of phenol resin-based activated carbon which is g; 1 to 5% by weight of polytetrafluoroethylene (PTFE; poly-tetrafluoroethylene) and 0.2 to 5% by weight of carboxymethylcellulose (CMC); 0.2-5% by weight of poly-N-vinylpyrrolidone (PVP) as a dispersion catalyst of the CMC; The electrode paste obtained by mixing the carbon fiber or the carbon tube 5-30% by weight of the conductive additive forming the nanostructure is mixed with a dispersion medium to slurry the conductive paste obtained by coating and bonding to a metal current collector. Electrode for electric double layer capacitor. The method of claim 1, wherein the conductive additive Hematite (Fe ₂ O ₃ ) powder and alumina (Al ₂ O ₃ ) powder is mixed in a weight ratio of 1: 1, put into a drum mixer and mixed for 3 hours, 10 g of the mixed powder was placed in an alumina container and kept at 1,300 for 2 hours in the air in a box-type electric furnace, The mass mixture was removed from the electric furnace, and 0.3 g of powder having a particle size of 100 or less was put in an alumina boat, and the temperature was raised to nitrogen up to 650 in a tubular furnace equipped with a quartz tube with a diameter of 60, and 1 l / min hydrogen and 0.1 l / min ethylene. After substituting with mixed gas for 40 minutes, reducing and carbon deposition reaction, substituting with nitrogen and cooling to room temperature An electrode for an electric double layer capacitor, wherein the carbon tube forms a hollow nanostructure having an average diameter of 10 to 50 deposited. The method of claim 1, wherein the conductive additive Hematite (Fe ₂ O ₃ ) powder and nickel oxide (NiO) powder are mixed in a weight ratio of 1: 1, mixed in a drum mixer for 3 hours, 10 g of the mixed powder was placed in an alumina container and kept in a box-type furnace for 2 hours at 900 in the air. 0.3 g of powder with an average particle size of 100 or less was put in an alumina boat and heated to nitrogen up to 550 in a tubular furnace equipped with a quartz tube with a diameter of 60. After substituting with a mixed gas of hydrogen 1 l / min and ethylene 0.2 l / min, reducing and carbon-depositing the reaction for 40 minutes, substituting with nitrogen, cooling to room temperature, An electrode for an electric double layer capacitor, wherein the carbon fiber is formed of a hollow nanostructure having an average diameter of 200 deposited. The method of claim 1, wherein the conductive additive Nickel oxide (Fe ₂ O ₃ ) powder and copper oxide (CuO) powder are mixed in a weight ratio of 7: 3, put into a drum mixer, and mixed for 3 hours, 10 g of the mixed powder was placed in an alumina container and kept in a box-type furnace for 1,000 hours at atmospheric temperature for 2 hours, and then cooled. 0.3 g of powder with an average particle size of 100 was placed in an alumina boat and heated to nitrogen up to 550 in a tubular furnace equipped with a quartz tube with a diameter of 60. Substituted with a mixed gas of hydrogen 1 l / min and acetylene 0.2 l / min, followed by reduction and carbon deposition reaction for 40 minutes, and then replaced with nitrogen and cooled to room temperature. An electrode for an electric double layer capacitor, wherein the carbon fiber is formed of a hollow nanostructure having an average diameter of 200 deposited. The electrode for an electric double layer capacitor according to claim 1, wherein the conductive paste has a viscosity of 500 to 50,000 cps. The electrode for an electric double layer capacitor according to claim 1, wherein said dispersion medium is water (distilled water). The metal current collector of claim 1 or 2, 3, or 4, wherein the metal current collector has a mesh foil having a plurality of voids, a thickness of 10 to 200 having an etching structure, and an etching degree of 5 to 80%. An electrode for an electric double layer capacitor, characterized by Ni, Al, or SUS metal body. An electric double layer prepared by coating a conductive paste obtained by mixing a coconut shell activated carbon, a phenol resin activated carbon, a binder, a conductive additive, and a dispersion medium on a metal current collector, and then performing a pressing process using a roll press. In the manufacturing method of the electrode for capacitors, 5 to 30% by weight of coconut shell carbon activated carbon having a specific surface area of 1,500 to 1,700 / g, 5 to 30% by weight of phenol resin based activated carbon having a specific surface area of 2,000 to 2,500 / g, and a specific surface area of 2,500 to 3,500 / g 10 to 50% by weight of powdered activated carbon of phenol resin-based activated carbon which is g; 1 to 5% by weight of polytetrafluoroethylene (PTFE; poly-tetrafluoroethylene) and 0.2 to 5% by weight of carboxymethylcellul-ose (CMC); 0.2-5% by weight of poly-N-vinylpyrrolidone (PVP) as a dispersion catalyst of the CMC; Preparing an electrode composition for mixing 5-30 wt% of a carbon fiber or a carbon tube conductive additive forming a nanostructure; Obtaining a conductive paste by adding a dispersion medium to the electrode composition in small amounts and measuring the viscosity to stir to have a predetermined viscosity; Coating the conductive paste on a metal foil-shaped metal current collector having a network structure in which a plurality of voids are formed, and coating and drying the upper and lower end surfaces or both sides; Subsequently, performing a pressing process using a heating roll heated to a temperature of 100 to 250 on the coated, dried one or both sides to sufficiently infiltrate the electrode material into the pores, and to completely adhere to the upper and lower surfaces of the current collector. Method of manufacturing an electrode for an electric double layer capacitor, characterized in that it comprises a step. The method of manufacturing an electrode for an electric double layer capacitor according to claim 8, wherein the conductive paste has a viscosity of 500 to 50,000 cps.

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