JP2008205275A - Method of manufacturing electrode material for electric double layer capacitor, electrode for electric double layer capacitor, electric double layer capacitor, and activated charcoal for electric double layer capacitor electrode - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a method of manufacturing an electrode material for an electric double layer capacitor, by which a residual of a functional group containing oxygen can be suppressed; an electrode for an electric double layer capacitor using the electrode material for the electric double layer capacitor obtained by the manufacturing method; an electric double layer capacitor with a high capacity and a stable performance using this electrode for the electric double layer capacitor; and an activated charcoal for an electric double layer capacitor electrode, in which an oxygen content is low and a specific surface area is large. <P>SOLUTION: In a hydrogen atmosphere or a hydrogen atmosphere diluted by nitrogen, an electromagnetic wave with a wavelength of 170 nm or less is irradiated to an activated charcoal with a BET specific surface area of 1,000 m<SP>2</SP>/g or more which is measured by a nitrogen absorbing method. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for producing an electrode material used for an electric double layer capacitor having an electrode layer and a current collector, an electrode for an electric double layer capacitor, an electric double layer capacitor, and activated carbon for an electric double layer capacitor electrode. is there.

  An electric double layer capacitor is a charge storage device that uses an electric double layer formed at the interface between a polarizable electrode and an electrolyte, and as the electrode material, activated carbon with a large surface area is used to increase capacitance. It is done. Among types of electric double layer capacitors that use organic electrolytes with high energy density, moisture can cause performance degradation, but activated carbon with a large surface area has the property of easily adsorbing moisture and has been adsorbed by activated carbon. It is necessary to remove moisture. In view of this, there has been proposed a method of manufacturing an electric double layer capacitor in which dry air is allowed to flow while irradiating the activated carbon with microwaves, and the residual moisture content of the activated carbon is suppressed to 1000 ppm or less. (For example, refer to Patent Document 1.)

JP 2003-100572 A (paragraph 0035, FIG. 1)

  However, even when the moisture is removed by performing a drying treatment as described above, various functional groups still remain on the surface of the activated carbon. Among these functional groups, hydrogen can be discharged as hydrogen gas from the electrode during charging / discharging, but if functional groups containing oxygen such as hydroxyl groups or carboxyl groups remain, charging / discharging Water is generated and remains in the electrode, causing the deterioration of the performance of the capacitor as described above. In addition, it is known that the functional group of activated carbon can be removed by heat treatment in vacuum at a high temperature of 800 ° C. to 1000 ° C. However, the surface area is reduced by high temperature treatment, and a high-capacity capacitor cannot be obtained. was there.

  The present invention has been made to solve the above-described problems, and provides a method for producing an electrode material for an electric double layer capacitor capable of suppressing the remaining functional groups containing oxygen, an electrode for an electric double layer capacitor, a high An object of the present invention is to obtain an electric double layer capacitor having stable capacity and performance, and an activated carbon for an electric double layer capacitor electrode having a low oxygen content and a large specific surface area.

In the method for producing an electrode material for an electric double layer capacitor according to the present invention, activated carbon having a BET specific surface area of 1000 m ² / g or more measured by a nitrogen adsorption method in a hydrogen atmosphere or a hydrogen atmosphere diluted with nitrogen has a wavelength of 170 nm or less. The electromagnetic wave is irradiated.

  According to this invention, it is possible to reduce the oxygen content without reducing the specific surface area of the activated carbon, and it is possible to obtain an electrode material for an electric double layer capacitor that can produce an electric double layer capacitor having a high capacity and stable performance. .

Embodiment 1 FIG.
1 and 2 show a manufacturing method of an electrode material for an electric double layer capacitor in Embodiment 1 for carrying out the present invention. FIG. 1 shows the manufacturing method and FIG. 2 shows the manufacturing process. It is a flowchart.

  In FIG. 1, an airtight cylindrical reaction vessel 1 (shown in a state where a part of the casing is cut out) includes a hydrogen supply device 2 for supplying hydrogen, a nitrogen supply device 3 for supplying nitrogen, and a vacuum. The pump 4 is connected to each other via valves 2V, 3Va and 4Va. A laser plasma type electromagnetic wave source 6 for generating soft X-rays having a wavelength of 4.275 nm is installed inside the reaction vessel 1. A raw material supply device 7 is connected to the upper part of the reaction vessel 1 via a valve 7V, and activated carbon as a raw material is supplied from the raw material supply device 7 via the valve 3Vb. Along with the nitrogen gas thus produced, it is injected into the reaction vessel 1 from the nozzle 7a. Further, the raw material supply device 7 is connected to the vacuum pump 4 through a valve 4Vb. And the container 8 which receives processed activated carbon is installed in the inner bottom face of the said reaction container 1, The exit 8a is connected with the exterior through the valve | bulb 8V.

The activated carbon used in the present invention is an activated carbon having a BET specific surface area measured by a nitrogen adsorption method of 1000 m ² / g or more and having a particle diameter of several tens of nanometers to several tens of micrometers, and is a carbon material (raw material) Phenol resin, petroleum coke, coconut shell, etc.) and carbonization, followed by activation methods such as a steam activation method and a molten alkali activation method. In addition, this activated carbon may be a commercially available product as long as the BET specific surface area measured by the nitrogen adsorption method is 1000 m ² / g or more.

Next, a manufacturing process is demonstrated using the flowchart of FIG.
First, the vacuum pump 4 (and the valve 4Va) is operated to extract gas from the reaction vessel 1 and reduce the pressure. Further, the nitrogen supply device 3 (and valve 3Va) is operated, nitrogen gas is introduced into the reaction vessel 1, and the air remaining in the reaction vessel is replaced with nitrogen, whereby oxygen in the reaction vessel 1 is replaced. Is removed (S100). Next, hydrogen is introduced from the hydrogen supply device 2 to form a (diluted) hydrogen atmosphere having a hydrogen concentration of 4% or less in the reaction vessel 1 (S110). At this time, the inside of the reaction vessel 1 is in a negative pressure state with respect to the outside air. In steps S100 and S110, it is necessary to repeat nitrogen introduction and depressurization operations in order to perform strict oxygen removal at the initial stage of operation of the apparatus. However, after starting the treatment of activated carbon, oxygen hardly remains in the reaction vessel 1 and a hydrogen atmosphere has already been formed. Therefore, pressure and hydrogen are reduced by performing decompression and introduction of each gas once. It is sufficient to adjust the concentration. The reaction vessel 1 is maintained at a temperature of about 150 ° C. by a heating means (not shown).

Next, preparation for injecting activated carbon into the reaction container 1 from the raw material supply device 7 is made (S120). First, the raw material supply apparatus 7 is filled with activated carbon having a specific surface area of 1000 m ² / g or more as a raw material. Then, the vacuum pump 4 (and the valve 4Vb) is operated, the air in the raw material supply device 7 containing activated carbon is extracted and decompressed, and then the nitrogen supply device 3 (and the valve 3Vb) is operated to supply nitrogen gas. Then, the air in the raw material supply device 7 is replaced with nitrogen and pressurized.

  When the raw material supply device 7 is ready, activated carbon is injected into the reaction container 1 and irradiated with soft X-rays to remove oxygen (S130). First, the electromagnetic wave generation source 6 is activated to irradiate almost the entire surface inside the reaction container 1 with soft X-rays. Then, when the valve 7V of the raw material supply device 7 is opened, the charged activated carbon is guided to the pressurized nitrogen and diffuses in the horizontal direction toward the inner wall of the upper part of the reaction vessel 1 decompressed from the nozzle 7a. Erupt. The ejected activated carbon settles in the diluted hydrogen atmosphere and receives soft X-rays irradiated from the electromagnetic wave generation source 6 during the sedimentation. At this time, the soft X-rays received by the activated carbon are electromagnetic waves having a wavelength of 4.275 nm (290 eV), which is about 5 eV energy larger than C = O binding energy (285 eV). Therefore, the C = O bond of the functional group remaining on the activated carbon that has received soft X-rays can be efficiently cut by soft X-rays. Moreover, since the C—O bond and the O—H bond have a lower binding energy than the C═O bond, the oxygen-containing bond is cleaved to release most of the oxygen-containing functional groups remaining on the activated carbon. Can do. And since the inside of the reaction vessel 1 is kept in a hydrogen atmosphere (diluted with nitrogen), hydrogen is preferentially bonded to the activated carbon from which the functional groups are liberated, and oxygen is removed and stabilized with hydrogen. Activated carbon accumulates in the container 8. Further, since the temperature inside the reaction vessel 1 is raised to about 150 ° C., even if water is generated by the liberated oxygen, it is not adsorbed on the activated carbon.

  Finally, the treated activated carbon deposited in the container 8, that is, the activated carbon for the electric double layer capacitor electrode, which is the electrode material for the electric double layer capacitor, is taken out (S140). When the injection of the activated carbon from the raw material supply device 7 is completed and the sedimentation of the injected activated carbon into the container 8 is completed, the nitrogen supply device 3 (and the valve 3Va) is operated, and the pressure in the reaction vessel 1 is reduced to the atmospheric pressure. Pressurize to maintain positive pressure. When the valve 8V is opened, the activated carbon flows down from the outlet 8a. At this time, nitrogen is supplied from the nitrogen supply device 3 to such an extent that the pressure of the reaction vessel 1 can be maintained at a positive pressure so that outside air does not enter the reaction vessel 1.

When the extracted activated carbon for electric double layer capacitor electrodes is analyzed, the specific surface area hardly changes before and after the oxygen removal treatment, and the BET specific surface area by the nitrogen adsorption method of 1000 m ² / g or more is maintained. Moreover, when the oxygen content is measured by elemental analysis, the oxygen content is reduced to 0.1% by weight (vs. carbon weight) or less.

Here, the conditions for the deoxygenation treatment were examined.
It has been found that the hydrogen concentration in the reaction vessel 1 is effective even if the concentration is lowered to about several thousand ppm as long as a state in which oxygen is completely absent can be formed. On the other hand, when oxygen was mixed during the treatment, it was found that the oxygen content of the activated carbon after treatment could be stably reduced to 0.1% or less by maintaining the hydrogen concentration at 1% or more. . Of course, it is possible to carry out with 100% hydrogen, but in consideration of convenience when jetting out or taking out activated carbon, nitrogen should be maintained so that the hydrogen concentration is kept below 4%, which is the lower combustion limit concentration of hydrogen. It was decided to dilute with. That is, it was found that it is desirable to form a hydrogen atmosphere diluted to a hydrogen concentration range of 1 to 4%.

  On the other hand, the electromagnetic wave irradiated to activated carbon was also tested for various wavelengths. As a result, when an electromagnetic wave having a wavelength of 370 nm to 2.5 nm is irradiated, an effect of reducing the oxygen content remaining in the activated carbon is seen. Further, in an electromagnetic wave having a wavelength range of 170 nm to 2.5 nm, oxygen is almost equal to the activated carbon. It was confirmed that the content could be reduced to 0.1% or less.

  The upper limit of the wavelength, that is, the lower limit of the energy of the electromagnetic wave is defined by the binding energy of the outer shell electrons in the binding energy in the functional group, and for the outer shell electrons of the C—O bond, the electromagnetic wave having a wavelength of 370 nm or less ( It was found that the bond can be broken by irradiating with ultraviolet rays. For example, the wavelength of an ultraviolet lamp used for adhesive curing or the like is 254 nm, and can be used for cutting a C—O bond. However, for the C═O bond, the binding energy wavelength of the outer electrons corresponds to an electromagnetic wave (ultraviolet light) of 170 nm, and in order to remove oxygen remaining in the activated carbon including C═O, the wavelength is 170 nm or less (energy It was found that the higher electromagnetic wave was necessary. For example, the wavelength of the xenon excimer lamp is 172 nm ± 15 nm, and by using the xenon excimer lamp as the electromagnetic wave generation source 6, oxygen in the activated carbon can be reduced to 0.1% by weight or less.

  On the other hand, in the case of electromagnetic waves in the ultraviolet region as described above, there is an ability to break the bond, but the permeability is small, it is difficult to reach the functional groups of the internal pores of the activated carbon, and the processing time is long. Thus, oxygen in the activated carbon can be efficiently removed by using an electromagnetic wave in a soft X-ray region having a higher transmission power than ultraviolet rays. For example, the 1 / e attenuation distance of the soft X-ray having the wavelength used in the first embodiment is 0.1 μm, and can easily reach the inner pores of the activated carbon and can be processed in a short time. However, since the soft X-ray source is generally more expensive than the ultraviolet ray source, if only the processing time becomes a problem, it can be replaced with the soft X-ray source by using a large number of ultraviolet ray sources.

  However, the transmission performance of soft X-rays improves as the wavelength becomes shorter. However, if the transmission performance is too high, the energy of electromagnetic waves is not absorbed and passes through activated carbon, and the bond cannot be cut. I understood. When the wavelength of soft X-rays is shorter than 2.5 nm (equivalent to 500 eV), it can be seen that the absorptance of the activated carbon decreases to half or less, and it is desirable to use electromagnetic waves having a wavelength of substantially 2.5 nm or more. In particular, an electromagnetic wave having a wavelength that is about 5 eV to 10 eV higher than the bond energy of C═O (285 eV) has high permeability, and the bond of the functional group containing oxygen in activated carbon can be cut most efficiently. Therefore, when an electromagnetic wave having a wavelength of 4.1 to 4.3 nm irradiated from a soft X-ray source having a center wavelength of 4.27 nm is used, oxygen in the activated carbon can be most efficiently removed.

  In this embodiment, in order to show the principle of the manufacturing method, an example in which activated carbon is simply injected into the atmospheric gas and settling is shown. However, the present invention is not limited to this, and the reaction vessel 1 is not limited to this. A function of rotating like a kiln may be provided, and electromagnetic waves may be irradiated while stirring the activated carbon inside.

Next, the manufacturing method of the electric double layer capacitor 20 as shown in FIG. 3 is demonstrated using the activated carbon for electric double layer capacitor electrodes which is the electrode material for electric double layer capacitors manufactured by the method mentioned above.
First, the electric double layer capacitor electrodes 21 and 22 are prepared using the activated carbon for the electric double layer capacitor electrode, the conductive additive, the binder, and the current collectors 23 and 25. As a method for producing the electrodes 21 and 22, for example, activated carbon powder and acetylene black as a conductive additive are dispersed in an N-methylpyrrolidone (NMP) solution of PVDF, and this mixture is collected by an aluminum current collector by a doctor blade method or the like. It is applied on top, dried, and pressed to form an electrode. Since the electrode 21 functions differently from the positive electrode and the electrode 22 functions differently from the negative electrode, they can be configured by combining activated carbon, a conductive additive, a binder, and current collectors 23 and 25 suitable for each. Alternatively, the polarizable electrodes 24 and 26 may be formed in advance using only activated carbon, a conductive additive, and a binder, and then bonded to the current collectors 23 and 25.

  The positive electrode 21 and the negative electrode 22 thus prepared are loaded into an exterior material 29 made of an aluminum laminate film through an insulating separator 27 for preventing a short circuit. The tab portion 23a of the positive electrode current collector 23 and the tab portion 25a of the negative electrode current collector 25 are led out of the exterior material 29 as leads. At this time, for the purpose of preventing the electrolyte solution 28 from leaking to the outside and preventing water or air from entering from the outside, the sealing portions of the positive electrode tab portion 23a and the negative electrode tab portion 25a are provided as sealing bodies (not shown). The modified polypropylene film was previously heat-welded. The separator 27 was a 35 μm paper separator. Then, the remaining side except for one side of the exterior portion 29 was heat-welded to produce a capacitor element.

Next, the electrolytic solution 28 is injected into the capacitor element thus created. As the electrolytic solution 28, a solution obtained by dissolving tetraethylammonium tetrafluoroborate (TEABF ₄ ) as an electrolyte in propylene carbonate so as to have a concentration of 1 mol / l was used. About 2 ml of electrolyte solution 28 is put through the opening of the bag-shaped exterior portion 29. Thereafter, the capacitor element filled with the electrolytic solution 28 was put in a vacuum vessel and evacuated to about 4 × 10 ³ Pa or less, whereby the positive electrode 21, the negative electrode 22 and the separator 27 were impregnated with the electrolytic solution 28. .

Next, after charging by applying a voltage of 3.2 V between the positive electrode 21 and the negative electrode 22 for 30 minutes, a load was connected between the positive electrode and the negative electrode, When fully discharged until the voltage reaches 1.5 V, hydrogen adsorbed on the activated carbon is generated as a gas by this charge and discharge. Therefore, in order to remove the hydrogen gas generated by the charge / discharge and further impregnate the electrolyte solution 28 into the electrodes 21 and 22, the outer packaging material is opened again by vacuuming to about 4 × 10 ³ Pa or less. The electric double layer capacitor 20 was constructed by welding one side of 29.

  The electric double layer capacitor 20 obtained by the above method was repeatedly charged and discharged at a charging voltage of 2.7 V and a charging / discharging current of 30 mA, and the capacitance was determined from the discharge energy. The capacitance was 40 F / g ( Activated carbon weight) and internal resistance was 1.1Ω. And even if it repeated 1000 times charging / discharging, a change was not seen by the electrostatic capacitance and internal resistance.

  On the other hand, regardless of the first embodiment, a similar electric double layer capacitor was prepared using activated carbon having an oxygen content of 3%, and a charge / discharge test was performed. The initial performance was the same as in the first embodiment. Although it was about the same as the electric double layer capacitor, it was found that the capacity was reduced by about 10% after 1000 charge / discharge cycles. When the electric double layer capacitor after charge / discharge was disassembled, the electric double layer capacitor according to the first embodiment hardly detected any water from the electrolyte. On the other hand, 0.1% moisture is detected from the electrolyte of the electric double layer capacitor using activated carbon containing 3% oxygen, and the oxygen contained in the activated carbon is the cause of moisture in the electrolyte. Was suggested.

In addition, when the activated carbon having a specific surface area of less than 1000 m ² / g is deoxygenated using the manufacturing method according to the first embodiment, changes in capacitance and internal resistance are observed even after 1000 charge / discharge cycles. However, the initial performance was lower than that of the electric double layer capacitor in the first embodiment, and it was found that it was difficult to obtain a high capacity electric double layer capacitor.

That is, by irradiating activated carbon with an electromagnetic wave having a wavelength of 170 nm or less in a hydrogen atmosphere or a hydrogen atmosphere diluted with nitrogen, the oxygen content is reduced without reducing the specific surface area of the activated carbon, and the specific surface area is 1000 m ² / An activated carbon having an oxygen content of 0.1 g or more and an oxygen content of 0.1% or less, that is, an electric double layer capacitor electrode material was obtained. And by configuring the electric double layer capacitor using activated carbon for electric double layer capacitor having a specific surface area of 1000 m ² / g or more and an oxygen content of 0.1% or less obtained by this production method, a high capacity can be obtained. An electric double layer capacitor with stable performance could be obtained.

Embodiment 2. FIG.
In the first embodiment, the method for removing oxygen from activated carbon, which is powder, is described as the electrode material for the electric double layer capacitor. In the second embodiment, the BET specific surface area measured by the nitrogen adsorption method is 1000 m. ² / g or more, and a polarizable electrode 40, that is, an electrode material for an electric double layer capacitor, which is formed of only activated carbon, a conductive additive, and a binder having a particle diameter of several tens of nanometers to several tens of micrometers, and having a certain form A method for removing oxygen from the activated carbon therein will be described. FIG. 4 is a diagram showing a method for manufacturing the electrode material for an electric double layer capacitor in the second embodiment. In the figure, an airtight casing 31 having an inlet 31I and an outlet 31E on the left and right (shown in a state where a part of the casing is cut out) includes a hydrogen supply device 2 for supplying hydrogen and a nitrogen supply device for supplying nitrogen. 3 are connected via valves 2V and 3V, respectively. A laser plasma type electromagnetic wave generation source 36 that generates soft X-rays having a wavelength of 4.275 nm is installed inside the casing 31, and the soft X-rays are directed from the electromagnetic wave generation source 36 toward the lower part of the casing. Is irradiated. The casing 31 is provided with a transport device 32 driven by a driving wheel 32a, and a polarizable electrode 40 on a flat plate placed on the belt 32b is introduced from the inlet 31I of the housing 31 by the transport device 32, and the outlet. It is discharged from 31E. A heating device 34 for raising the temperature inside the casing is installed on the inner bottom surface of the casing 31.

Next, the manufacturing process will be described.
First, the nitrogen supply device 3 (and valve 3V) and the hydrogen supply device 2 (and valve 2V) are operated in the housing 31 to form a (diluted) hydrogen atmosphere with a hydrogen concentration of 4% or less. Note that the inside of the housing 31 is heated to about 150 ° C. by the heating device 34.

  Next, the transport device 32 is driven, and the polarizable electrode 40 formed in front of the inlet 31I is transported in order. The inlet 31I and the outlet 31E form a double door (not shown) to prevent outside air from being mixed into the casing 31 when the polarizable electrode 40 passes, and to maintain a hydrogen atmosphere in the casing 31. Can do. When the polarizable electrode 40 passes under the electromagnetic wave generation source 36, the soft X-rays irradiated from the electromagnetic wave generation source 36 are received. At this time, the polarizable electrode 40 has a thickness of mm, but soft X-rays having high transmission performance reach the activated carbon constituting the polarizable electrode 40, and, as in the first embodiment, the binding of oxygen To release oxygen-containing functional groups remaining on the activated carbon and be stabilized with hydrogen. Moreover, since the inside of the housing 31 is heated to about 150 ° C., even if water is generated by the liberated oxygen, it is not adsorbed on the activated carbon in the polarizable electrode 40.

When the polarizable electrode 40 coming out from the outlet 31E is decomposed and the activated carbon in it is separated and analyzed, the specific surface area hardly changes before and after the oxygen removal treatment, and is determined by a nitrogen adsorption method of 1000 m ² / g or more. The BET specific surface area was maintained. Moreover, when the oxygen content was measured by elemental analysis, the oxygen content was reduced to 0.1% by weight (vs. carbon weight) or less.

  In the second embodiment, since the object to be processed is a thick polarizable electrode or electrode, it is necessary to irradiate soft X-ray electromagnetic waves with high permeability in order to reduce the oxygen content.

  And when the electric double layer capacitor was manufactured using the polarizable electrode 40 from which oxygen was removed by this method, an electric double layer capacitor having high capacity and stable performance could be obtained as in the first embodiment. It was.

  Note that the polarizable electrode 40 used in the present embodiment was obtained by removing moisture in advance in dry air at about 200 ° C. However, a heater for drying was provided in the electrode manufacturing apparatus, and moisture caused by drying was used. You may make it perform removal and oxygen removal by electromagnetic waves at once.

  In addition, even after a current collector plate (not shown) is bonded to the polarizable electrode 40 to form an electrode, the current collector plate portion is placed in the lower side so that it can be irradiated with soft X-rays from above. As in the above embodiment, the oxygen in the activated carbon in the electrode can be removed.

That is, by irradiating the polarizable electrode or electrode with soft X-rays in a hydrogen atmosphere or a hydrogen atmosphere diluted with nitrogen, the oxygen content is reduced without reducing the specific surface area of the activated carbon, and the specific surface area is 1000 m. A polarizable electrode containing activated carbon having an oxygen content of ² / g or more and an oxygen content of 0.1% or less, that is, an electrode material for an electric double layer capacitor could be obtained. And by this manufacturing method, by constituting an electric double layer capacitor using a polarizable electrode containing activated carbon having a specific surface area of 1000 m ² / g or more and an oxygen content of 0.1% or less, the performance is high and the capacity is high. A stable electric double layer capacitor could be obtained.

It is a figure which shows the manufacturing method of the electrode material for electric double layer capacitors in Embodiment 1 of this invention. It is a flowchart which shows the manufacturing process of the electrode material for electric double layer capacitor electrodes in Embodiment 1 of this invention. It is sectional drawing which shows the structure of the electrical double layer capacitor in Embodiment 1 of this invention. It is a figure which shows the manufacturing method of the electrode material for electric double layer capacitors in Embodiment 2 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Reaction container, 2 Hydrogen supply apparatus, 3 Nitrogen supply apparatus, 4 Vacuum pump, 6,36 Electromagnetic wave generation source, 7 Raw material supply apparatus, 8 Container, 20 Electric double layer capacitor 21, 22 Electrode for electric double layer capacitor

Claims (5)

A method for producing an electrode material for an electric double layer capacitor, wherein activated carbon having a BET specific surface area of 1000 m ² / g or more measured by a nitrogen adsorption method is irradiated with an electromagnetic wave having a wavelength of 170 nm or less in a hydrogen atmosphere or a hydrogen atmosphere diluted with nitrogen. The method for producing an electrode material for an electric double layer capacitor according to claim 1, wherein the electromagnetic wave has a wavelength in the range of 4.1 to 4.3 nm. The electrode for electric double layer capacitors using the electrode material for electric double layer capacitors obtained by the manufacturing method of Claim 1 or Claim 2. An electric double layer capacitor using the electric double layer capacitor electrode according to claim 3. An activated carbon for an electric double layer capacitor electrode having a BET specific surface area measured by a nitrogen adsorption method of 1000 m ² / g or more and an oxygen content of 0.1 wt% or less.

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