JP2001089119A - Carbonaceous material, method for producing and electric double layer capacitor using the carbonaceous material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a carbonaceous material having a high specific surface area capable of providing an electrostatic capacity when used as an electrode material of electric double layer capacitor. SOLUTION: This carbonaceous material comprises 10-60% based on the whole pore volume of micro pore volume, 20-70% based on the whole pore volume of meso pore volume and <=20% based on the whole pore volume of macro pore volume and has 0.3 cm3/g to 2.0 cm3/g whole pore volume and 1,000-2,500 m2/g total specific surface area.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a porous carbonaceous material which can be suitably used as an electrode of an electric double layer capacitor or the like, a method for producing the same, and an electric double layer capacitor using the carbonaceous material. INDUSTRIAL APPLICABILITY The electric double layer capacitor of the present invention can be suitably used for a wide range of applications such as a power supply for various portable devices, a standby power supply for home electric appliances, an optical communication UPS, and an electric vehicle power supply.

[0002]

2. Description of the Related Art Conventional electric double layer capacitors include:
An element in which a separator is interposed between a pair of electrodes mainly composed of activated carbon formed on a current collector, a coin type sealed in a metal case with a gasket that insulates both a metal case and a metal lid with an electrolytic solution, or A winding type in which a winding element formed by winding a pair of sheet-like electrodes through a separator is housed in a metal case together with an electrolytic solution and sealed so that the electrolytic solution does not evaporate from an opening of the case is known. ing.

Further, as an application for a large current and a large capacity, a multilayer electric double-layer capacitor in which an element formed by laminating a large number of sheet electrodes via a separator is incorporated has been proposed (Japanese Patent Laid-Open No. Hei 4 (1994)). -154106, JP-A-3-
No. 203311 and JP-A-4-286108). That is, a state in which a rectangular sheet-shaped electrode is used as a positive electrode and a negative electrode, a plurality of layers are alternately laminated via a separator to form a laminated element, and a positive electrode lead member and a negative electrode lead member are connected to the ends of the positive electrode and the negative electrode by caulking. Housed in the case with
The element was impregnated with an electrolytic solution and sealed with a lid.

Conventionally, electrodes constituting an electric double layer capacitor are mainly composed of activated carbon having a large specific surface area, and a high dielectric material such as water or propylene carbonate is used in an electrolytic solution in order to dissolve the electrolyte at a high concentration. % Of the solvent has been used.

[0005] In such an electrode containing activated carbon as a main component, the electric charge of the electric double layer formed on the surface of the activated carbon itself contributes to the capacitance (capacitance) of the electric double layer capacitor. Activated carbon with a large surface area is used. However, the specific surface area of activated carbon is currently about 3,000 m ² / g at the maximum, and the capacity per unit volume of electric double layer capacitors using the same has almost reached the limit.

On the other hand, in the charging / discharging process of a capacitor, its charging and discharging characteristics are governed by the passing speed of electrolyte ions in the pores of activated carbon. When the specific surface area increases, the portion occupied by the finer pores in the activated carbon increases, and within the fine pores, as described later, it is difficult for smooth movement of ions to be performed, and the number of conductive paths is reduced. Therefore, there was a problem that the resistance of the activated carbon itself increased as a phenomenon.

[0007] Generally, the capacitance of the electrode per unit area of the electrode, although the water / mercury interfaces are said to 20~30μF / cm ^2, it small about 5μF / cm ² in the electrode using activated carbon Only values are obtained.

[0008] The capacitance per unit area of the electrode of the capacitor is determined by the solid state (electrode) based on its configuration and operation principle.
And the physical properties of both liquids (electrolyte). Regarding the electrolyte, various solvents, electrolytes, and the like have been studied, and it can be said that the electrolyte is almost optimized.
On the other hand, on the solid side, a porous electrode mainly comprising activated carbon is mainly used, and various studies have been made in the past, but only a very small capacity has been obtained as described above.

Although various explanations have been made for this reason, one is attributed to the fact that the relationship between the moving speed of electrolyte ions in the pores and the specific surface area is not optimized.

[0010] For example, it is considered that one of the causes is that electrolyte ions cannot sufficiently enter the inside of the pores because the pore diameter of the activated carbon is too small. That is, even if activated carbon having a high specific surface area is produced as well as pursuing high capacitance of a capacitor, if the diameter of the pores is smaller than the diameter of the electrolyte ion, the so-called "does not contribute to the increase in capacitance". Only the “unused surface” increases,
Not only does the capacitance of the electrode as a whole not increase, but rather the capacitance may decrease.

In general, since the electrolyte is associated with the solvent molecules in the solvent (solvation), in order to increase the capacitance of the capacitor, the pore diameter of the activated carbon must be adjusted in consideration of the solvation. It is considered that the optimization needs to be performed in a range sufficiently larger than the maximum diameter of the ions. That is, it is necessary to optimize the distribution of the pore diameter of the activated carbon serving as the electrode in relation to the ion size of the electrolyte.

However, when the pore diameter of the activated carbon is increased, the pore volume of the activated carbon as a whole is also increased, so that the bulk density of the activated carbon is reduced. For this reason, activated carbon with a large pore diameter requires
The mass of the activated carbon that can be filled per unit volume of the cell was reduced, and the energy stored in the unit volume tended to be reduced. As described above, from the practical viewpoint, in the electrode material for the electric double layer capacitor, it is required to maximize the energy stored per unit volume.

Conventionally, from such a viewpoint, micropores (micropores), mesopores (mesopores), macropores (macropores) and the like of carbonaceous materials such as activated carbon used as electrodes for electric double layer capacitors have been used. Some attempts have been made to define the mutual relationship (see, for example,
Nos. 811, 6-56416, 8-119
614, JP-A-8-153653, JP-A-10-2
08895, JP-A-10-297912), all of which are limited to partial optimization, and there is no attempt to optimize the relationship among all three pore regions.

The activated carbon is usually a plant-derived carbon source such as sawdust and coconut shells, or a carbon source derived from coal or petroleum-based raw materials such as coke and pitch, or a phenol resin, a furfuryl alcohol resin, a vinyl chloride resin. And the like, and is produced by carbonizing and activating a synthetic polymer-based carbon source.

[0015] Carbonization is generally carried out at 300 ° C to 2,000 ° C.
This is performed by heating the carbon source in a non-oxidizing atmosphere in a temperature range of about ° C. Activation is performed by heating the carbide thus obtained in a weakly oxidizing gas containing carbon dioxide and water vapor from 500 ° C to 1,100 ° C to oxidize and deplete the carbide to form pores, (Gas activation). Alternatively, after mixing the carbide with an alkali metal hydroxide (for example, KOH) several times its mass, the mixture is heated at a temperature not lower than the melting point of the metal hydroxide and not higher than 1,000 ° C. in an inert gas atmosphere for several tens of minutes to 10 Time, preferably number
Heat for about 10 minutes to 5 hours to increase the surface area (alkali metal hydroxide activation). After completion of the activation, the alkali metal oxide is sufficiently washed and removed.

The pore structure of the activated carbon obtained as described above is basically largely determined by the properties of the raw material serving as the carbon source. It has been difficult to obtain a pore structure suitable for a double-layer capacitor.

[0017]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a carbonaceous material having a high specific surface area capable of solving the above-mentioned problems of the prior art and having a high capacitance, and a method for producing the same. An object of the present invention is to provide a high-capacity and high-reliability electric double layer capacitor using this carbonaceous material as an electrode material.

[0018]

According to the present invention, a carbonaceous material, a method for producing a carbonaceous material, a carbonaceous material obtained by the production method, and a carbonaceous material obtained by the production method are described below. Is provided.

(I) A micropore volume having a pore diameter of 10 to 20 mm accounts for 10 to 60% of the total pore volume, and a pore diameter of 20 to 200 mm.
The mesopore volume in the range of 20 to 70% of the total pore volume, the macropore volume exceeding 200 mm in pore diameter accounts for 20% or less of the total pore volume, and the total fine volume per unit mass The pore volume is 0.3-2.0 cm ³ / g and the specific surface area is 1,00
A carbonaceous material characterized by being from 0 to 2,500 m ² / g.

(Ii) A method for producing a porous carbonaceous material, comprising: (1) a liquid containing a volatile component having a boiling point of 120 to 400 ° C. and a viscosity of 0.1 to 100 Pa · s at 25 ° C. (2) a pulverizing step of pulverizing the cured product, and (3) carbonizing the pulverized cured product in a non-oxidizing atmosphere to obtain a cured product. A carbonization step of obtaining a carbonized material whose mass reduction to 400 ° C. is 2 to 50% by mass before carbonization, and (4) an activation step of activating the carbonized material. Material manufacturing method.

(Iii) The carbonaceous material obtained by the method described in (ii) above, wherein the micropore volume in the range of pore diameter of 10 to 20 ° is 10 to 60% of the total pore volume. , Pore diameter 20 ~ 20
The mesopore volume in the range of 0 mm is 20 to 70% of the total pore volume, the macropore volume exceeding the pore diameter of 200 mm is 20% or less of the total pore volume, and the total The pore volume is 0.
3 to 2.0 cm ³ / g and specific surface area of 1,000 to 2,50
A carbonaceous material characterized by being 0 m ² / g.

(Iv) An electric double layer capacitor comprising an electrode containing the carbonaceous material as described in (i).

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.

The carbonaceous material of the present invention is a porous carbonaceous material, wherein a micropore volume having a pore diameter of 10 to 20% accounts for 10 to 60% of the total pore volume and a pore diameter of 20 to 20%. A mesopore volume in the range of ~ 200 mm accounts for 20-70% of the total pore volume, and a pore diameter of 20
Macropore volume of greater than 0 Å along with account for more than 20% of the total pore volume, the total pore volume is 0.3cm ³ /g~2.0 cm ³ / g, and a specific surface area of 1,000 ~2,500m ² / g 2 (in the present invention, “pore diameter 10 to
"20 mm" means a range of pore diameter of 10 mm or more and less than 20 mm. The term "pore diameter of 20 to 200 mm" means a pore diameter of 20 mm to 200 mm. ).

Basically, in the carbonaceous material of the present invention, micropores having a pore diameter in the range of 10 to 20 mm are portions that effectively contribute to the development of capacitance, while micropores having a pore diameter of 20 to 200 mm.
The mesopores in the range described above mainly serve to supply the electrolyte solution from the outer surface of the carbonaceous material particles to the inner micropores and supply electrolyte ions to the micropores. Further, macropores having a pore diameter of more than 200 mm hardly contribute to the development of the capacitance and the like, which is a portion which causes a decrease in the bulk density of the carbonaceous material.

According to the present invention, the micropore volume, the mesopore volume, and the macropore volume are optimized as follows. That is,

In the carbonaceous material of the present invention, the micropore volume having a diameter of 10 to 20 ° through which electrolyte ions can enter and exit is 10 to 60% of the total pore volume, preferably 10 to 45%, more preferably 10 to 45%.
Accounts for ~ 25%. Thus, within this range of pores,
Most of the developed capacitance is taken care of. If the ratio of the pore volume of the pore diameter of 10 to 20 mm to the total pore volume is smaller than this range, sufficient capacitance cannot be obtained, and if larger than this range, the bulk density of the carbonaceous material increases, In the electrode body, it is difficult to fill a required amount of the carbonaceous material in a unit volume.

The mesopore volume having a pore diameter of 20 to 200 mm is 20 to 70%, preferably 35 to 65% of the total pore volume,
More preferably, it accounts for 40 to 60%. If the ratio of the pore volume in the range of 20 to 200 mm in diameter to the total pore volume is smaller than this range, a sufficient amount of electrolyte ions cannot be supplied to the micropores, and Insufficient electrolyte ion holding capacity makes it impossible to obtain sufficient capacitance. On the other hand, if it is larger than this range, the bulk density of the carbonaceous material is too low, and it is difficult to fill a required amount of the carbon material per unit volume when forming the electrode body.

As described above, since the pores in this range have a small surface area, rather than directly contributing to an increase in capacitance, the pores having a pore diameter of 10 to 20 mm mainly responsible for the development of capacitance are mainly used. It is presumed that it plays a role of supplying a sufficient amount of electrolyte ions to the pores.

Further, the carbonaceous material of the present invention has a pore diameter
The macropore volume of more than 200% occupies 20% or less, preferably 15% or less, more preferably 10% or less of the total pore volume, and may not be substantially contained. Large pores having a pore diameter of more than 200 mm have a small specific surface area and do not contribute to an increase in capacitance, and also reduce the bulk density of the carbonaceous material. An electrode having a high energy density per unit volume is provided by being defined in the scope of the present invention.

The carbonaceous material of the present invention has a micropore volume,
The mesopore volume and the macropore volume are optimized, and the total pore volume and the total specific surface area are defined as follows.

The total pore volume is at least 0.3 to 2.0 cm ³ /
g, preferably 0.5-1.5 cm ³ / g, more preferably 0.5
~ 1.0 cm ³ / g. If the total pore volume is smaller than this range, a sufficient capacitance cannot be obtained, and if the total pore volume is larger than this range, the electrical resistance of the carbonaceous material increases and the bulk density decreases, which is not preferable. .

The specific surface area is 1,000 to 2,500 m ² / g,
Preferably 1,000 to 2,200 m ² / g, more preferably 1,00
0 to 1,500 m ² / g. If the specific surface area is smaller than this range, sufficient capacitance cannot be obtained, and if it is larger than this range, the bulk density of the carbonaceous material decreases, which is not preferable.

The carbonaceous material of the present invention having the above-mentioned properties can be obtained by a production method comprising the following steps specified in the present invention.

(1) First, the composition contains volatile components having a boiling point of 120 to 400 ° C., preferably 150 to 380 ° C., and more preferably 180 to 350 ° C., and has a viscosity of 0.1 to 100 Pa at 25 ° C.
.S, preferably 0.2 to 80 Pa.s, more preferably
Prepare a liquid thermosetting resin of 0.5 to 50 Pa · s,
This is cured to obtain a cured product.

The volatile component may be a dimer or a trimer composed of polymerized units constituting the resin contained in the thermosetting resin, or may be contained by adding a solvent having a boiling point in the above range to the resin. Alternatively, the solvent may be used as a volatile component. In addition,
In the present invention, when a solvent is added to the thermosetting resin, the viscosity at 25 ° C. indicates the viscosity of the resin in a state where the solvent is added (that is, the viscosity of the resin just before curing).

When a thermosetting resin having the above-mentioned viscosity is used, the composition can be cured in air or in a non-oxidizing atmosphere, and the mass reduction up to 200 ° C. is 2 to 50% by mass before curing. You can get the body.

If the viscosity of the thermosetting resin is higher than the above range, the free components are not uniformly dispersed in the thermosetting resin, which is not preferable. On the other hand, if the viscosity is lower than the range described above, the fixed carbon content at the time of carbonizing the resin is significantly reduced, so that the density of the obtained carbonized product, and hence the density of the activated carbonaceous material is significantly reduced, When the carbonaceous material is used as an electrode material for an electric double layer capacitor, the energy density per unit volume of the capacitor is undesirably reduced.

The viscosity of the resin can be controlled mainly by the amount of the volatile component contained therein, but the amount of the volatile component within the suitable viscosity range varies depending on the molecular weight of the resin itself and the type of the volatile component. Therefore, in the production method of the present invention, the amount of the volatile component is not particularly limited as long as the viscosity of the resin is within the above specified range.

When the boiling point range of the volatile component contained in the thermosetting resin is lower than the above-specified range, the volatile component such as a solvent is not included in the resin at the time of curing the resin, and the volatile component is discharged outside the system. Due to separation, it does not lead to the formation of pores in the carbonization step. On the other hand, if the contained volatile component is higher than the boiling point range specified in the present invention, the carbonization of the resin proceeds before volatilization, so that cracks and the like are generated in the carbonized product upon the release of the volatile component, and As a result, the density of the obtained carbonized product is extremely lowered, which is not preferable.

In the present invention, since the boiling point range of the volatile component and the viscosity of the raw material resin of the carbonaceous material are defined in the above ranges, the resin maintains appropriate fluidity when it is cured, And harden while containing various free ingredients.
During carbonization, these encapsulated components and decomposition components of the resin are appropriately volatilized and separated to form pores as gas holes, so that relatively large mesopores with a diameter of about 20 to 200 mm have already been formed after carbonization. Is formed.

The presence of such relatively large mesopores makes it possible to use a reactive gas (activating gas) in the next activation step.
It is considered that, for example, the diffusion of water vapor or carbon dioxide into the carbonized material is uniform, and the formation of micropores of 10 to 20 ° is promoted.

Furthermore, as a result of the viscosity and boiling point range of the volatile component being limited to the appropriate ranges specified above, the formation of macropores exceeding 200 ° is limited to a certain range or less.
It is presumed that finally, a carbonaceous material having an optimized pore structure of micropores, mesopores and macropores defined in the present invention can be obtained.

The thermosetting resin used in the present invention includes:
Phenol resin, melamine resin, urea resin, furan resin, epoxy resin, alkyd resin, unsaturated polyester resin, diallyl phthalate resin, etc. can be used,
Phenol resins are most preferred because they are easy to handle during production, have a high carbonization yield, and are easy to control pores.

The volatile components include unreacted phenol, components contained in the thermosetting resin such as dimer and trimer of polymerized units constituting the phenol resin, and ethylene glycol, tetramethylene glycol, propylene glycol, and trimethylene. Glycols, glycols such as glycerin and polyols, alcohols such as octanol and butanol, ketones such as cyclohexanone, acetophenone and methylbutylketone, amines such as ethanolamine and diethylamine, and boiling points such as ethers such as anisole 120 A solvent at -400 ° C can be suitably used by adding it to the resin.

In this case, the curing agent was added in an amount of 1% by mass based on the resin.
As described above, preferably 5 to 20% by mass is kneaded, and
A kneading step of kneading the kneaded material of not more than 0.2% by mass, preferably 0.25 to 1.0% by mass, to obtain a kneaded body, and a curing step of curing the kneaded body can also be performed.

The type of the kneader for performing the kneading is not particularly limited, but includes a liquid resin and a solvent.
Alternatively, a powdery curing agent or a curing agent that can be kneaded so that the curing accelerator is uniformly mixed is preferable. Such a kneader may be any type of a container rotary kneader in which a container itself rotates or a container fixed type kneader in which a rotating blade is mounted in a fixed container. The former includes, for example, a horizontal cylindrical type, an inclined cylindrical type, a V type, a double cone type, a cubic type, and the like, and the latter includes, for example, a ribbon type, a single-axis rotor type, a pug mill type, a planetary motion type, and a high-speed flow type. There are a mold and a rotary movement type, and any of them can be suitably used.

The above resin (or resin kneaded product) is heated in a temperature range usually used for curing a thermosetting resin, for example, 150 to 350.
Curing at a temperature of preferably from 180 to 250 ° C. At this time, a solvent contained in the resin and free components such as dimer and trimer, which are polymerization units constituting the resin, are released while appropriately stirring the system, and a part remains in the system, and the mesopores remain. A cured product which is easy to be activated and contains moderate voids having developed therein can be obtained.

When a phenol resin is used as the thermosetting resin, any of a resole type resin and a novolak type resin may be used.
In the case of a novolak resin, a curing agent such as formaldehyde or hexamethylenetetramine is added, more preferably, an acid such as oxalic acid or salicylic acid is added as a curing accelerator, and the curing agent is added at 150 to 350 ° C., preferably 180 to 350 ° C. 250
The temperature may be raised to 10 ° C. for 10 to 360 minutes, preferably about 10 to 120 minutes.

The amount of the curing agent is preferably 1% by mass or more. If it is less than 1% by mass, the crosslinking density does not increase, the fixed carbon decreases, and the bulk density decreases. The amount of the curing accelerator is preferably 5% by mass or less,
The mesopore ratio can be increased in accordance with the amount added, but no further improvement in the mesopore ratio is observed even if an amount exceeding this is added. The apparatus for curing is not particularly limited, and any of a fixed-bed heating furnace, an electric furnace, and the like is suitably used.

(2) Next, the cured product obtained as described above is pulverized. The type of the pulverizer is not particularly limited, but a pulverizer capable of pulverizing the cured product to at least several tens mm or less, preferably several mm or less, and more preferably 1 mm or less is desirable. Such crushers include, for example, dodge crushers, double roll crushers, edge runners, jaw crushers, cone crushers,
Hammer mills, rotary crushers, desk crushers, rod mills, ball mills, tube mills, roller mills, attrition mills, jet mills, micron mills, micromizers, and the like can be suitably used.

(3) Subsequently, the pulverized cured product is carbonized in a non-oxidizing atmosphere. Carbonization is the conversion of a carbon precursor made of a thermosetting resin such as a phenolic resin into a solid carbon body having a carbon network. Carbonization is carried out at 300 to 2,000 ° C., preferably 500 to 1, under a non-oxidizing atmosphere of an inert gas such as nitrogen, argon, helium, xenon, neon, carbon dioxide, flue gas or a mixture thereof.
It is carried out by heating in a temperature range of about 000 ° C. for 10 minutes to 80 hours, preferably for 10 minutes to 30 hours.

The apparatus for performing carbonization is not particularly limited, but includes a fixed bed heating furnace, a fluidized bed heating furnace, a moving bed heating furnace,
Any of an internal heating type or an external heating type rotary kiln, an electric furnace, and the like are preferably employed.

In this carbonization step, the volatile components remaining in the cured resin are released as a gas, and the
20-200 mm of mesopores are formed.

When this is quantitatively expressed, for example, the mass loss from room temperature to 400 ° C. during carbonization measured by using a thermal mass spectrometer or the like is at least 2 to 2 before carbonization.
It is desirably 50% by mass, preferably 5 to 40% by mass, and more preferably 5 to 30% by mass. If the mass loss is less than this, the amount of pore volume formed by the release of volatile components is not sufficient, and if it is too large, the density of the carbonaceous material obtained in the next activation step is excessive. Is not preferred.

(4) Finally, the carbonized material is activated to obtain a porous carbonaceous material. Activation is a process of growing and developing the fine pore structure of the solid carbon body generated by the carbonization treatment. In the case of performing gas activation, activation is performed in a weakly oxidizing activation gas atmosphere containing any one or more of steam, carbon dioxide, oxygen, hydrogen chloride, chlorine, and the like, preferably at 500 to 1,100 ° C., and more preferably at 700 ° C. ~
It is carried out by heating in a temperature range of 1,000 ° C. for about 5 minutes to 10 hours. When activated with an alkali metal hydroxide, potassium hydroxide, sodium hydroxide,
One or more kinds selected from lithium hydroxide, rubidium hydroxide and cesium hydroxide, preferably potassium hydroxide, are mixed with the carbonized material in a mass ratio of 0.2 to 5.0 times the amount of the carbonized material to form an alkali metal hydroxide. Heating at a temperature above the melting point of the product, preferably 300 to 1,000 ° C., more preferably 400 to 900 ° C., for 30 minutes to 10 hours, preferably 80 minutes to 5 hours, in an inert gas or non-oxidizing gas atmosphere. It is done by doing. Activation can be performed several times by combining the above-described gas activation and alkali metal hydroxide activation. In this case, the treatment conditions may be appropriately changed so that the pore structure of the activated carbonaceous material falls within a desired numerical range.

The apparatus for activating is not particularly limited, and the same apparatus as that used for carbonization can be used. The fixed-bed heating furnace, the fluidized-bed heating furnace, the moving-bed heating furnace, and the internal heat Any of a rotary kiln, an electric furnace and the like of an external or external heating type is suitably employed.

By the above activation treatment, many micropores having a diameter of about 10 to 20 ° are formed. At this time, the activation conditions are selected so that the mass reduction rate of the carbon material during activation is 30 to 90% by mass, more preferably 50 to 80% by mass in the case of gas activation, and the alkali metal hydroxide activation is performed. In the case of 5
When the conditions are selected so as to be 50 to 50% by mass, more preferably 10 to 40% by mass, the pore volume and the specific surface area become more optimal ranges, which is preferable.

The pore characteristics such as the pore diameter, the pore volume and the specific surface area in the present invention were determined as follows, using Autosorb 1 (Autosorb 1) manufactured by Quantachrome.
-1) (or a device with equivalent functions)
Is the value measured using

The pore diameter and pore volume are determined in advance in a vacuum.
By analyzing the adsorption isotherm obtained by adsorbing nitrogen gas at liquid nitrogen temperature on a sample dried at 200 ° C for 12 hours or more by the so-called BJH method, the relationship between the pore diameter and the pore volume is calculated. Ask. Here, the BJH method means Barrett-Joyner-Halen
This is a method of determining the distribution of the pore volume with respect to the cylindrical pore diameter according to the standard model of da (JACS, 73 (1951) 373).
-377). The specific surface area is the relative pressure of the nitrogen adsorption isotherm.
The range of 0.001 to 0.05 was calculated by analyzing with the BET multipoint method.
Here, the BET method is a method of measuring the surface area by the Brunauer-Emmett-Teller method (JACS, 60 (1938) 309).

According to the present invention, there is provided an electric double layer capacitor having an electrode containing, as an electrode material, a carbonaceous material having the above-mentioned pore characteristics as a main component, and more preferably, an organic solvent as an electrolytic solution. The present invention provides a capacitor using an organic electrolytic solution in which an electrolyte is dissolved.

As the electrolytic solution of the capacitor of the present invention, basically, an aqueous electrolytic solution and an organic electrolytic solution can be used. Particularly, when an organic electrolytic solution is used, the electrolytic solution is stored per unit volume. The amount of energy to be obtained is increased, which is preferable. In the case of an organic electrolytic solution, since the decomposition potential of the electrolytic solution is more than twice that of the aqueous electrolytic solution, the aqueous electrolytic solution has an energy density proportional to one half of the product of the square of the voltage and the capacitance. This is because it is more advantageous than a liquid.

The carbonaceous material in the present invention is thus:
Because it has a large number of pores in the range of 10 to 20 mm in diameter, which is larger than activated carbon mainly containing pores with a diameter of less than 10 mm, an electrolyte with a larger ionic radius was dissolved in an organic solvent. Even when an organic electrolyte is used, electrolyte ions can freely enter and exit the pores, and a high capacitance can be exhibited. As already mentioned, since the total pore volume is specified to be in the optimal range,
A capacitor cell having a high energy density per unit volume without forming a bulky carbonaceous material can be formed.

More specifically, the electrode material of the electric double layer capacitor according to the present invention comprises the above-mentioned carbonaceous material and a binder, more preferably a conductive material. This electrode is
For example, a carbonaceous material powder and a binder such as polytetrafluoroethylene and preferably a conductive material are kneaded in the presence of a solvent such as alcohol to form a sheet, and after drying,
It is obtained by bonding to a current collector via a conductive adhesive or the like. Further, a powder of a carbonaceous material and a binder and preferably a conductive material are mixed with a solvent to form a slurry, coated on a current collector metal foil, and dried to obtain an electrode integrated with the current collector. Can also.

As the binder, for example, polytetrafluoroethylene, polyvinylidene fluoride, a crosslinked polymer of a fluoroolefin / vinyl ether copolymer, carboxymethylcellulose, polyvinylpyrrolidone, polyvinyl alcohol, polyacrylic acid and the like can be used. The content of the binder in the electrode is preferably about 0.5 to 20% by mass based on the total amount of the carbonaceous material and the binder. If the amount of the binder is less than 0.5% by mass, the strength of the electrode becomes insufficient,
If it exceeds 0% by mass, electric resistance increases and capacity decreases, which is not preferable. From the viewpoint of electrode strength and capacity balance, the amount of the binder is more preferably 0.5 to 10% by mass. As the crosslinking agent for the crosslinked polymer, amines,
Preferred are polyamines, polyisocyanates, bisphenols or peroxides.

As the conductive material, powders of carbon black, natural graphite, artificial graphite, titanium oxide, ruthenium oxide and the like are used. Among them, it is preferable to use Ketjen black or acetylene black, which is a kind of carbon black, since the effect of improving conductivity is large even in a small amount.

The compounding amount of the conductive material such as carbon black in the electrode should be 5% by mass or more, especially 10% by mass or more based on the total amount with the carbonaceous material powder so as to improve the conductivity. preferable. If the compounding amount of the conductive material is too large, the compounding ratio of the carbonaceous material decreases and the capacitance of the electrode decreases, so that the compounding amount of the conductive material in the electrode is 40% by mass or less, particularly 30% by mass or less. Is preferred.

As the solvent for forming the slurry, those capable of dissolving the above binder are preferable, and N-methylpyrrolidone, dimethylformamide, toluene, xylene, isophorone, methyl ethyl ketone, ethyl acetate, methyl acetate, ethyl acetate, dimethyl phthalate, methanol , Ethanol, isopropanol, butanol, water and the like are appropriately selected.

The current collector of the electrode may be any conductor that is electrochemically and chemically resistant to corrosion. Stainless steel, aluminum, titanium, tantalum, nickel, or the like is used as a current collector for an electrode mainly composed of a carbonaceous material. Among them, stainless steel and aluminum are preferred current collectors in terms of both performance and cost.

The shape of the current collector may be a foil, a nickel or aluminum foam metal having a three-dimensional structure, or a stainless steel net or wool.

As the electrolytic solution of the electric double layer capacitor of the present invention, a known or well-known aqueous or organic electrolytic solution can be used. The most preferable result is obtained when an organic electrolytic solution is used.

Examples of the organic solvent include electrochemically stable ethylene carbonate, propylene carbonate, butylene carbonate, γ-butyrolactone, sulfolane,
Sulfolane derivative, 3-methylsulfolane, 1,2-dimethoxyethane, acetonitrile, glutaronitrile,
A solvent comprising at least one selected from the group consisting of valeronitrile, dimethylformamide, dimethylsulfoxide, tetrahydrofuran, dimethoxyethane, methylformate, dimethylcarbonate, diethylcarbonate and ethylmethylcarbonate is preferred. These can be used as a mixture.

Both the positive electrode and the negative electrode have the high specific surface area carbon of the present invention.
When an organic material is used as the main component, the
The resolution is R¹ R^Two R^Three R^Four N⁺Or R¹ R^Two 
R^ThreeR^Four P⁺(R¹ , R^Two , R^Three , R^Four Are independent
Represents an alkyl group having 1 to 6 carbon atoms. The fourth represented by
Grade onium cation and BF_Four ^-, PF_Four ^-, ClO _Four 
^-, CF_Three SO_Three ^-And (SO_Two R^Five ) (SO_Two R⁶ )
N^-(R^Five , R⁶ Are each independently an alkyl having 1 to 4 carbon atoms
A kill group or an alkylene group;^Five And R⁶ Form a ring
It may be. Anion selected from the group consisting of
Are preferred.

Specifically, for example, (C ₂ H ₅ ) ₄ NB
F ₄ , (C ₂ H ₅ ) ₃ (CH ₃ ) NBF ₄ , (C ₂ H
₅ ) ₄ PBF ₄ and (C ₂ H ₅ ) ₃ (CH ₃ ) PBF ₄
And the like are preferred. The concentration of these salts in the electrolyte is from 0.1 to 2.5 mol / l, more preferably from 0.5 to
It is preferably about 2 mol / l.

In the present invention, as the separator inserted between the positive electrode and the negative electrode, for example, a polypropylene fiber nonwoven fabric, a glass fiber nonwoven fabric, a synthetic cellulose paper, etc. can be suitably used.

The electric double layer capacitor according to the present invention is a coin-type capacitor in which a separator is interposed between a pair of sheet electrodes and accommodated in a metal case together with an electrolytic solution, and a pair of positive and negative electrodes are wound with a separator interposed therebetween. Any structure such as a round shape and a stacked type in which a large number of sheet electrodes are stacked via a separator can be adopted.

[0077]

The present invention will be described below in detail with reference to examples and comparative examples. In Examples and Comparative Examples, the pore diameter,
The pore volume and specific surface area were measured as follows using Autosorb 1 manufactured by Kantachrome.

The pore diameter and the pore volume are determined in advance in a vacuum.
It is obtained by analyzing the adsorption isotherm obtained by adsorbing nitrogen gas at the liquid nitrogen temperature to a sample dried at 200 ° C for 12 hours or more by the BJH method and calculating the relationship between the pore diameter and the pore volume. Was. The specific surface area was calculated by analyzing the relative pressure range of 0.001 to 0.05 of the nitrogen gas adsorption isotherm by the BET multipoint method.

Example 1 (1) Dimer and trimer of polymerized units constituting a phenol resin having a boiling point in the range of 180 to 350 ° C. contain volatile components, and have a viscosity of 5 Pa · s at 25 ° C. Hexamethylenetetramine as curing agent for phenolic resin A
Add 10 parts by mass and knead with a kneader.
The composition was cured while the temperature was raised to ℃.

Next, the powder was pulverized to a particle size of several mm or less by a hammer mill, heated to 600 ° C. in a nitrogen stream with a rotary kiln, and kept for 2 hours to be carbonized in a nitrogen atmosphere. At this time, the mass loss from room temperature to 400 ° C is 15% by mass.
Met. Further, the mixture was activated at 800 ° C. for 4 hours under a nitrogen gas stream containing saturated steam at 40 ° C. The mass loss during activation was 45% by mass. After the activation was completed, the powder was pulverized to an average particle size of 5 μm using a ball mill to obtain a carbonaceous material A.

The specific surface area of the carbonaceous material A is 1,500 m ² /
g, the total pore volume is 0.95 cm ³ / g, and the ratio of the pore volume of 10-20 mm in diameter to the total pore volume is 20%,
The ratio of the 200Å pore volume to the total pore volume is 48%,
The ratio of the pore volume exceeding 200 mm in diameter to the total pore volume was 7%.

(2) A mixture of 80% by mass of carbonaceous material A, 10% by mass of furnace black (Ketjen Black EC manufactured by Ketjen Black International) as a conductive material, and 10% by mass of polytetrafluoroethylene as a binder was mixed with ethanol. Is added, and the mixture is roll-rolled to obtain an electrode sheet having a thickness of 0.65 mm.
Dried for hours. Two electrodes having a diameter of 12 mm were punched out of this sheet, and the positive electrode and the negative electrode were bonded to a stainless steel 316 case and an upper lid with a graphite-based conductive adhesive, respectively.

After vacuum-drying the upper lid and the case at 250 ° C. for 4 hours, a propylene carbonate solution containing (C ₂ H ₅ ) ₃ (CH ₃ ) NBF ₄ at a concentration of 1 mol / l was dried in a dry argon atmosphere. The electrodes were impregnated. Next, the two electrodes were opposed to each other with a polypropylene nonwoven fabric separator interposed therebetween, and sealed with a polypropylene insulating gasket. This coin-type electric double layer capacitor has a diameter of 1
The thickness was 8.3 mm and the thickness was 2.0 mm.

The completed coin type electric double layer capacitor
Apply a voltage of 2.5 V and set the capacitance (combined capacitance of positive and negative electrodes)
And the internal resistance was measured. As a result, the capacitance and the internal resistance were 4.32 F and 8.2 Ω, respectively.

Example 2 (1) The phenol resin of Example 1 was mixed with 3% by mass of ethylene glycol as a solvent, and the viscosity at 25 ° C. was 2%.
A liquid resin B of Pa · s was obtained. A carbonaceous material B was obtained from this resin B under the same conditions as in Example 1 except that the activation temperature was 850 ° C. The mass loss up to 400 ° C during carbonization was 18% by mass, and the mass loss during activation was 65% by mass.
Met. The specific surface area of this carbonaceous material is 1,900 m ² / g,
The total pore volume is 1.44 cm ³ / g, and the ratio of the pore volume of 10 to 20 mm in diameter to the total pore volume is 35% and the diameter of 20 to 200 mm.
The ratio of the pore volume of Å to the total pore volume is 40%, diameter
The ratio of the pore volume exceeding 200 mm to the total pore volume is
5%.

(2) Using this carbonaceous material B (C ₂
H _{5) 3} (CH ₃₎ instead of the _{NBF 4 (C 2 H 5)} 4
A coin-type electric double-layer capacitor was produced in the same manner as in Example 1 except that NBF ₄ was used, and the characteristics were evaluated.

The completed coin-type electric double layer capacitor
Apply a voltage of 2.5 V and set the capacitance (combined capacitance of positive and negative electrodes)
And the internal resistance was measured. As a result, the capacitance and the internal resistance were 4.10 F and 7.8 Ω, respectively.

Example 3 (1) The phenolic resin of Example 2 was cured at 200 ° C.
A carbonaceous material C was obtained under the same conditions as in Example 1 except that an intermediate hold of 0 minutes was added. Incidentally, the mass loss up to 400 ° C. during carbonization is 10% by mass, and the mass loss during activation is
It was 50% by mass. The specific surface area of the carbonaceous material C is 1,
800 m ² / g, total pore volume is 0.85 cm ³ / g, diameter 10 ~
The ratio of the pore volume of 20 mm to the total pore volume is 32%, and the ratio of the pore volume of 20 to 200 mm in diameter to the total pore volume is 3%.
The ratio of the pore volume exceeding 0% and the pore volume exceeding 200 mm in the total pore volume was 4%.

(2) Using this carbonaceous material C, a coin-type electric double layer capacitor was produced in the same manner as in Example 1, and the characteristics were evaluated.

The completed coin type electric double layer capacitor
A voltage of 2.5 V was applied, and the electrostatic capacity (combined capacity of the positive and negative electrodes) and the internal resistance were measured. As a result, the capacitance and internal resistance are
They were 3.75F and 8.7Ω, respectively.

Example 4 (1) From the phenolic resin B of Example 2, the activation time was 6
A carbonaceous material D was obtained under the same conditions as in Example 1 except that the time was changed. The mass loss up to 400 ° C. during carbonization was 18% by mass, and the mass loss during activation was 69% by mass. The specific surface area of this carbonaceous material is 2,060 m ² / g, the total pore volume is 1.36 cm ³ / g, and the ratio of the pore volume of 10 to 20 mm in diameter to the total pore volume is 51%, 20-200 直径 in diameter
Of the total pore volume is 28%, diameter 20
The ratio of the pore volume exceeding 0% to the total pore volume is 2
%Met.

(2) Using this carbonaceous material D (C ₂
H _{5) 3} (CH ₃₎ instead of the _{NBF 4 (C 2 H 5)} 4
A coin-type electric double-layer capacitor was produced in the same manner as in Example 1 except that NBF ₄ was used, and the characteristics were evaluated.

The completed coin-type electric double layer capacitor
A voltage of 2.5 V was applied, and the electrostatic capacity (combined capacity of the positive and negative electrodes) and the internal resistance were measured. As a result, the capacitance and the internal resistance were 3.94 F and 12.0 Ω, respectively.

Example 5 (1) 10 parts by mass of a resole resin was mixed with the phenol resin of Example 2 to obtain a liquid resin E having a viscosity of 12 Pa · s at 25 ° C. From this resin E, a carbonaceous material E was obtained under the same conditions as in Example 1 except that the curing time was halved and the activation temperature was 850 ° C. Incidentally, the mass loss up to 400 ° C. during carbonization was 22% by mass, and the mass loss during activation was 66% by mass. The specific surface area of this carbonaceous material is 2,100 m ² / g
The total pore volume is 1.81 cm ³ / g, the ratio of the pore volume of 10 to 20 mm in diameter to the total pore volume is 38%, and the diameter of 20 to 200 mm.
The ratio of the pore volume to the total pore volume is 45%, diameter 20
The ratio of the pore volume exceeding 0% to the total pore volume is 6%.
%Met.

(2) Using this carbonaceous material E, a coin-type capacitor was produced in the same manner as in Example 1, and the characteristics were evaluated.

The completed coin-type electric double layer capacitor
A voltage of 2.5 V was applied, and the electrostatic capacity (combined capacity of the positive and negative electrodes) and the internal resistance were measured. As a result, the capacitance and the internal resistance were 3.94F and 12.0Ω, respectively.

Example 6 (1) 10% by mass of hexamethylenetetramine as a curing agent was added to phenol resin A of Example 1, and 0.25% by mass of salicylic acid was further mixed as a curing accelerator. To obtain a liquid resin F of 11 Pa · s. From this resin F, a carbonaceous material F was obtained under the same conditions as in Example 1. Incidentally, the mass decrease to 400 ° C. during carbonization was 18% by mass. The specific surface area of this activated carbon is 1,600 m ² / g,
The total pore volume is 0.97 cm ³ / g, and the ratio of the pore volume of 10 to 20 mm in diameter to the total pore volume is 22%, and the ratio of the pore volume of 20 to 200 mm in diameter to the total pore volume. Is 53%, diameter 200
The ratio of the pore volume exceeding Å to the total pore volume is 5%
Met.

(2) Using this carbonaceous material F, a coin-type electric double layer capacitor was produced in the same manner as in Example 1, and the characteristics were evaluated.

The completed coin-type electric double layer capacitor
Apply a voltage of 2.5 V and set the capacitance (combined capacitance of positive and negative electrodes)
And the internal resistance was measured. As a result, the capacitance and the internal resistance were 3.94 F and 9.5 Ω, respectively.

Example 7 (1) 10% by mass of hexamethylenetetramine as a curing agent was added to the phenol resin A of Example 1, and 0.25% by mass of oxalic acid was further mixed as a curing accelerator. A liquid resin G having a viscosity of 11.5 Pa · s was obtained. From this resin G, a carbonaceous material G was obtained under the same conditions as in Example 1. Incidentally, the mass decrease to 400 ° C. during carbonization was 19% by mass. The specific surface area of this activated carbon is 1,620 m ² / g,
The total pore volume is 0.93 cm ³ / g, and the ratio of the pore volume of 10 to 20 mm in diameter to the total pore volume is 25%, and the ratio of the pore volume of 20 to 200 mm in diameter to the total pore volume. Is 51%, diameter 200
The ratio of the pore volume exceeding Å to the total pore volume is 6%
Met.

(2) Using this carbonaceous material G, a coin-type electric double layer capacitor was produced in the same manner as in Example 1, and the characteristics were evaluated.

The completed coin-type electric double layer capacitor
Apply a voltage of 2.5 V and set the capacitance (combined capacitance of positive and negative electrodes)
And the internal resistance was measured. As a result, the capacitance and the internal resistance were 3.88 F and 9.1 Ω, respectively.

Example 8 (1) The phenol resin A of Example 1 was treated with hexamethyl
Add lentetramine as a curing agent by 10% by mass,
Mix 5% by mass of propylene glycol,
A liquid resin H having a degree of 3.5 Pa · s was obtained. Is this resin H
Thus, a carbonaceous material H was obtained under the same conditions as in Example 1.
The mass loss to 400 ° C during carbonization was 33% by mass.
there were. The specific surface area of this activated carbon is 1,800 m^Two/ g, all fine
Hole volume 1.25cm ^Three/ g, the total pore volume of 10-20 mm in diameter
The percentage of the pore volume is 18% and the pore diameter is 20 ~ 200mm
The ratio of the volume to the total pore volume is 61% and the diameter is 200 mm.
The ratio of the excess pore volume to the total pore volume is 3%.
Was.

(2) Using this carbonaceous material H, a coin-type electric double layer capacitor was produced in the same manner as in Example 1, and the characteristics were evaluated.

The completed coin-type electric double layer capacitor
Apply a voltage of 2.5 V and set the capacitance (combined capacitance of positive and negative electrodes)
And the internal resistance was measured. As a result, the capacitance and the internal resistance were 3.51 F and 8.8 Ω, respectively.

[Comparative Example 1] (1) A dimer of polymerized units constituting a phenol resin was removed from resin A of Example 1 by a recycle preparative GPC, and 15% by mass of ethylene glycol was further added as a solvent. Thus, a liquid resin I having a viscosity of 0.08 Pa · s at 25 ° C. was obtained. From the resin I, a carbonaceous material I was obtained under the same conditions as in Example 1. The mass loss up to 400 ° C during carbonization was 6% by mass, and the mass loss during activation was 50% by mass.
Met. The specific surface area of this carbonaceous material I is 1,500 m ² / g
The total pore volume is 0.73 cm ³ / g, and the ratio of the pore volume of 10 to 20 mm in diameter to the total pore volume is 24% and the diameter of 20 to
The proportion of the 200 細孔 pore volume to the total pore volume is 10%,
The ratio of the pore volume exceeding 200 mm in diameter to the total pore volume was 1%.

(2) Using this carbonaceous material I, a coin-type electric double layer capacitor was produced in the same manner as in Example 1, and the characteristics were evaluated.

In the completed coin type electric double layer capacitor
Apply a voltage of 2.5 V and set the capacitance (combined capacitance of positive and negative electrodes)
And the internal resistance was measured. As a result, the capacitance and the internal resistance were 2.65 F and 12.2 Ω, respectively.

Comparative Example 2 (1) Ethylene glycol was removed from resin A of Example 1 by a recycle preparative GPC, and the viscosity at 25 ° C. was 120.
A liquid resin J of Pa · s was obtained. Example 1 from this resin J
Under the same conditions as above, a carbonaceous material J was obtained. The mass loss up to 400 ° C. during carbonization was 5% by mass, and the mass loss during activation was 25% by mass. The specific surface area of the carbonaceous material J is 900 m ² / g, the total pore volume is 0.41 cm ³ / g, and the ratio of the pore volume of 10 to 20 mm in diameter to the total pore volume is 20%. The ratio of the pore volume having a diameter of 20 to 200 mm to the total pore volume was 8%, and the ratio of the pore volume exceeding 200 mm to the total pore volume was 2%.

(2) Using this carbonaceous material J, a coin-type electric double layer capacitor was produced in the same manner as in Example 1, and the characteristics were evaluated.

A completed coin-type electric double layer capacitor
A voltage of 2.5 V was applied, and the electrostatic capacity (combined capacity of the positive and negative electrodes) and the internal resistance were measured. As a result, the capacitance and the internal resistance were 1.13F and 20.1Ω, respectively.

Comparative Example 3 (1) Ethylene glycol was removed from Resin I of Comparative Example 1 by 10% by mass using a recycle preparative GPC, and 5% by mass of distilled water having a boiling point of 100 ° C. was added as a volatile component. A liquid resin K having a viscosity at 0.5 ° C. of 0.5 Pa · s was obtained. A carbonaceous material K was obtained from this resin K under the same conditions as in Example 1. The mass loss up to 400 ° C. during carbonization was 5% by mass, and the mass loss during activation was 52% by mass.

The specific surface area of the carbonaceous material K is 1,600 m ² /
g, the total pore volume is 0.70 cm ³ / g, and the ratio of the pore volume of 10 to 20 mm in diameter to the total pore volume is 20%,
The ratio of the 200Å pore volume to the total pore volume is 4%,
The ratio of the pore volume exceeding 200 mm in diameter to the total pore volume was 1%.

(2) Using this carbonaceous material K, a coin-type electric double layer capacitor was produced in the same manner as in Example 1, and the characteristics were evaluated.

In the completed coin type electric double layer capacitor
Apply a voltage of 2.5 V and set the capacitance (combined capacitance of positive and negative electrodes)
And the internal resistance was measured. As a result, the capacitance and the internal resistance were 2.80 F and 13.5Ω, respectively.

Comparative Example 4 (1) Ethylene glycol was added to the resin J of Comparative Example 2 in an amount of 5% by mass and the boiling point range was 390 to 460 ° C. as a volatile component.
25% by adding 3% by mass of a 4-ring polycyclic aromatic
, A liquid resin L having a viscosity of 80 Pa · s was obtained. From this resin L, a carbonaceous material L was obtained under the same conditions as in Example 1. The mass loss up to 400 ° C. during carbonization was 8% by mass, and the mass loss during activation was 67% by mass.

The specific surface area of this carbonaceous material L is 2,050 m ² / g
, The total pore volume is 0.89 cm ³ / g, and the ratio of the pore volume of 10 to 20 mm in diameter to the total pore volume is 25%, the diameter of 20 to 20 mm.
The ratio of the pore volume of 0% to the total pore volume was 5%, and the ratio of the pore volume exceeding 200 mm in diameter to the total pore volume was 1%.

(2) Using this carbonaceous material L, a coin-type electric double layer capacitor was produced in the same manner as in Example 1, and the characteristics were evaluated.

In the completed coin type electric double layer capacitor
Apply a voltage of 2.5 V and set the capacitance (combined capacitance of positive and negative electrodes)
And the internal resistance was measured. As a result, the capacitance and the internal resistance were 2.85 F and 11.5 Ω, respectively.

Comparative Example 5 (1) A carbonaceous material M was obtained under the same conditions as in Example 1 except that the resin A of Example 1 was used and the curing time was tripled. The mass loss up to 400 ° C. during carbonization was 1% by mass, and the mass loss during activation was 40% by mass.

The specific surface area of the carbonaceous material M is 1,300 m ² /
g, the total pore volume is 0.64 cm ³ / g, and the ratio of the pore volume of 10 to 20 mm in diameter to the total pore volume is 15%, the diameter of 20 to 20 mm.
The ratio of the pore volume of 0 mm to the total pore volume was 2%, and the ratio of the pore volume exceeding 200 mm in diameter to the total pore volume was 0.5%.

(2) Using this carbonaceous material M, a coin-type electric double layer capacitor was produced in the same manner as in Example 1, and the characteristics were evaluated.

The completed coin type electric double layer capacitor
Apply a voltage of 2.5 V and set the capacitance (combined capacitance of positive and negative electrodes)
And the internal resistance was measured. As a result, the capacitance and the internal resistance were 1.95F and 15.5Ω, respectively.

Comparative Example 6 (1) The viscosity at 25 ° C. is 5 Pa · s and 180 to 350 ° C.
The carbonaceous material N was obtained under the same conditions as in Example 1 using a phenol resin N containing a volatile component having a boiling point range of
The mass loss up to 400 ° C. during carbonization was 51% by mass, and the mass loss during activation was 77% by mass.

The specific surface area of the carbonaceous material N is 1,200 m ² /
g, the total pore volume is 2.55 cm ³ / g, and the ratio of the pore volume of 10 to 20 mm in diameter to the total pore volume is 9%,
The ratio of the 200Å pore volume to the total pore volume is 65%,
The ratio of the pore volume having a diameter of 200 mm or more to the total pore volume was 22%.

(2) Using this carbonaceous material N, a coin-type electric double layer capacitor was produced in the same manner as in Example 1, and the characteristics were evaluated.

In the completed coin type electric double layer capacitor
Apply a voltage of 2.5 V and set the capacitance (combined capacitance of positive and negative electrodes)
And the internal resistance was measured. As a result, the capacitance and the internal resistance were 1.54 F and 27.5Ω, respectively.

Comparative Example 7 (1) By adding 5% by mass of ethylene glycol to Resin J of Comparative Example 2, the viscosity at 25 ° C. was 35 Pa · s.
Liquid resin O was obtained. A carbonaceous material O was obtained from this resin under the same conditions as in Example 1. 400 ° C during carbonization
The mass loss up to 1% was 1% by mass, and the mass loss during activation was 64% by mass.

The specific surface area of this carbonaceous material O is 1,800 m ² / g
, The total pore volume is 0.85 cm ³ / g, and the ratio of the pore volume of 10 to 20 mm in diameter to the total pore volume is 21% and the diameter of 20 to 20 mm.
The ratio of the pore volume of 0 mm to the total pore volume was 8%, and the ratio of the pore volume exceeding 200 mm in diameter to the total pore volume was 2%.

(2) Using this carbonaceous material O, a coin-type electric double layer capacitor was produced in the same manner as in Example 1, and the characteristics were evaluated.

The completed coin type electric double layer capacitor
Apply a voltage of 2.5 V and set the capacitance (combined capacitance of positive and negative electrodes)
And the internal resistance was measured. As a result, the capacitance and the internal resistance were 2.26 F and 9.5 Ω, respectively.

Comparative Example 8 (1) 20 parts by mass of a resole resin was added to resin A of Example 1, and a liquid resin P having a viscosity of 0.7 Pa · s at 25 ° C.
I got A carbonaceous material P was obtained under the same conditions as in Example 1 except that no curing agent was added to the resin P. In addition,
The mass loss to 400 ° C during carbonization is 59% by mass,
The mass loss during activation was 25% by mass.

The specific surface area of this carbonaceous material P is 1,750 m ² /
g, the total pore volume is 2.51 cm ³ / g, and the ratio of the pore volume of 10 to 20 mm in diameter to the total pore volume is 8%,
The ratio of the 200Å pore volume to the total pore volume is 65%,
The ratio of the pore volume exceeding 200 mm in diameter to the total pore volume was 17%.

(2) Using this carbonaceous material P, a coin-type electric double layer capacitor was produced in the same manner as in Example 1, and the characteristics were evaluated.

The completed coin type electric double layer capacitor
Apply a voltage of 2.5 V and set the capacitance (combined capacitance of positive and negative electrodes)
And the internal resistance was measured. As a result, the capacitance and the internal resistance were 1.39F and 24.3Ω, respectively.

Comparative Example 9 (1) Ethylene glycol was removed from the resin I of Comparative Example 1 by 2% by mass using a recycle preparative GPC to obtain a liquid resin Q having a viscosity of 1 Pa · s at 25 ° C. A carbonaceous material Q was obtained under the same conditions as in Example 1 except that no curing agent was added to the resin Q. The mass loss up to 400 ° C. during carbonization was 52% by mass, and the mass loss during activation was 44% by mass.

The specific surface area of the carbonaceous material Q is 1,500 m ² /
g, the total pore volume is 1.61 cm ³ / g, and the ratio of the pore volume of 10-20 mm in diameter to the total pore volume is 18%,
The ratio of the 200Å pore volume to the total pore volume is 60%,
The ratio of the pore volume exceeding 200 mm in diameter to the total pore volume was 20%.

(2) Using this carbonaceous material Q, a coin-type electric double layer capacitor was produced in the same manner as in Example 1, and the characteristics were evaluated.

A completed coin-type electric double layer capacitor
Apply a voltage of 2.5 V and set the capacitance (combined capacitance of positive and negative electrodes)
And the internal resistance was measured. As a result, the capacitance and the internal resistance were 2.10 F and 19.5 Ω, respectively.

Comparative Example 10 (1) To phenol resin A of Example 1 was added 0.5% by mass of hexamethylenetetramine as a curing agent to obtain a liquid resin R having a viscosity of 4.5 Pa · s at 25 ° C. From this resin R, a carbonaceous material R was obtained under the same conditions as in Example 1. Incidentally, the mass decrease to 400 ° C. during carbonization was 27% by mass. The specific surface area of this activated carbon is 1,050 m ² /
g, the total pore volume is 0.75 cm ³ / g, and the ratio of the pore volume having a diameter of 10 to 20 ° to the total pore volume is 18%, and the diameter is 20 to 200 mm.
The ratio of the pore volume of Å to the total pore volume is 61%, the diameter is
The ratio of the pore volume exceeding 200 mm to the total pore volume is
3%.

(2) Using this carbonaceous material R, a coin-type electric double layer capacitor was produced in the same manner as in Example 1, and the characteristics were evaluated.

The completed coin-type electric double layer capacitor
Apply a voltage of 2.5 V and set the capacitance (combined capacitance of positive and negative electrodes)
And the internal resistance was measured. As a result, the capacitance and the internal resistance were 1.32 F and 22.5 Ω, respectively. The results of the examples and comparative examples are summarized in Table 1 above.

[0143]

[Table 1]

[0144]

According to the carbonaceous material of the present invention, the pore volume of the micropore region mainly contributing to the development of the capacitance and the pore volume of the mesopore region mainly contributing as the supply source of the electrolyte ions are optimized. As a result, an electrode for an electric double layer capacitor mainly using this carbonaceous material does not become bulky, and provides an electric double layer capacitor having a high capacitance per unit volume and a low internal resistance. Can be.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yasuhiro Mogi 1-3-1, Kudankita 4-chome, Chiyoda-ku, Tokyo Inside the Danei Building Ad Chemco Co., Ltd. (72) Inventor Kazuaki Tabayashi 4-chome, Kudankita, Chiyoda-ku, Tokyo 1-3 Toei Eikyu Dankoku Building Ad Chemco Co., Ltd. (72) Inventor Toru Shimoyama 1150 Hazawacho, Kanagawa-ku, Yokohama-shi, Kanagawa Prefecture Asahi Glass Co., Ltd. (72) Inventor Kazuhiko Yamada 1150 Hazawacho, Kanagawa-ku, Yokohama-shi, Kanagawa Prefecture Address Asahi Glass Co., Ltd. (72) Inventor Yasuo Shinozaki 1150 Hazawacho, Kanagawa-ku, Yokohama-shi, Kanagawa Prefecture F-term in Asahi Glass Co., Ltd. 4G046 CB08 HA03 HB05 HC03 HC08 HC09 HC10 HC11

Claims (8)

[Claims] A micropore volume having a pore diameter in the range of 10 to 20 mm accounts for 10 to 60% of the total pore volume, and a mesopore volume having a pore diameter in the range of 20 to 200 mm corresponds to the total pore volume. Macropore volume greater than 20-70% and pore diameter greater than 200 mm
%, The total pore volume per unit mass is 0.3 to 2.0 cm ³ / g, and the specific surface area is 1,000 to
A carbonaceous material characterized by being 2,500 m ² / g. 2. A method for producing a porous carbonaceous material, comprising: (1) a liquid containing a volatile component having a boiling point of 120 to 400 ° C. and a viscosity at 25 ° C. of 0.1 to 100 Pa · s. A curing step of curing a thermosetting resin to obtain a cured body, (2)
A pulverizing step of pulverizing the cured product, (3) the pulverized cured product is carbonized in a non-oxidizing atmosphere, and the mass reduction to 400 ° C. during carbonization is 2 to 50% by mass before carbonization A method for producing a carbonaceous material, comprising: a carbonization step of obtaining a carbonized body; and (4) an activation step of activating the carbonized body. 3. In the step (1), a curing agent is added to the thermosetting resin in an amount of 1% by mass or more based on the thermosetting resin and kneaded, and a curing accelerator is added to the thermosetting resin. The method for producing a carbonaceous material according to claim 2, wherein the kneaded body is obtained by kneading a kneaded body by adding and kneading 5% by mass or less. 4. The method according to claim 2, wherein the thermosetting resin is a phenol resin. 5. A carbonaceous material obtained by the method for producing a carbonaceous material according to any one of claims 2 to 4, wherein a micropore volume having a pore diameter of 10 to 20 ° is a total pore volume. Volumetric
10 to 60%, the mesopore volume in the range of pore diameter 20 to 200 mm is 20 to 70% of the total pore volume, and the macropore volume exceeding the pore diameter 200 mm is the total pore volume. Less than 20% of
A carbonaceous material having a total pore volume per unit mass of 0.3 to 2.0 cm ³ / g and a specific surface area of 1,000 to 2,500 m ² / g. 6. An electric double layer capacitor comprising an electrode containing the carbonaceous material according to claim 1. 7. The electric double layer capacitor according to claim 6, comprising an organic electrolytic solution obtained by dissolving an electrolyte in an organic solvent. 8. The method according to claim 1, wherein the organic solvent is ethylene carbonate,
Lopylene carbonate, butylene carbonate, dimethyl
Leucarbonate, ethyl methyl carbonate, diethyl
Carbonate, acetonitrile, glutaronitrile,
From relonitrile, sulfolane and sulfolane derivatives.
At least one member selected from the group consisting of
¹ R^Two R^Three R^Four N⁺Or R¹ R^Two R^Three R^Four P⁺(R
¹ , R ^Two , R^Three , R^Four Each independently has 1 to 6 carbon atoms
Shows an alkyl group. ) Quaternary onium kathio represented by
And BF_Four ^-, PF_Four ^-, ClO_Four ^-, CF_Three SO_Three
^-And (SO_Two R^Five ) (SO_Two R⁶ ) N^-(R^Five , R⁶ 
Each independently represents an alkyl group having 1 to 4 carbon atoms. )
A salt comprising an anion selected from the group consisting of
The electric double layer capacity according to claim 7, which has a mechanical system electrolyte.
Sita.