JP2005235873A - Nonacqueous electrolyte based electric double layer capacitor, electrode active substance for use therein, carbon material and precursor of carbon material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high capacity nonaqueous electrolyte based electric double layer capacitor using an electrode active substance produced by activating a carbon material obtained from a specific petroleum based heavy oil, and to provide the electrode active substance, the carbon material and a precursor of the carbon material. <P>SOLUTION: A specific petroleum based heavy oil is held for three hours or longer at a temperature of 400-600°C under a pressure of 2.0 MPa or less to obtain a precursor of carbon material, and the precursor is heat treated at 600-900°C to obtain the carbon material. Furthermore, a nonaqueous electrolyte based electric double layer capacitor using an electrode active substance produced by activating the carbon material, the electrode active substance for the nonaqueous electrolyte based electric double layer capacitor, the carbon material becoming its material and its precursor are provided. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a non-aqueous electrolyte based electric double layer capacitor, an electrode active material used therefor, a carbon material, and a precursor thereof.

  In recent years, new electronic devices such as mobile phones, notebook personal computers, and PDAs (personal digital assistants) have emerged one after another, and IC products and microcomputers built into these products have been developed due to the development competition for miniaturization and weight reduction of these products. Etc. are also becoming smaller and higher performance.

  However, such an element such as an IC memory or a microcomputer may malfunction due to a memory interruption or a function stop of an electronic device in response to an instantaneous power interruption or a voltage drop. In fact, if computer equipment takes no appropriate measures, even if it is a slight voltage drop of 10 to 20%, it will stop functioning or memory contents will be lost in just 0.003 to 0.02 seconds. The function of the device is paralyzed.

  As countermeasures, Ni-Cd batteries and aluminum electrolytic capacitors have been used for backup power supplies. However, these power sources have not been sufficient in terms of operating temperature range, number of charge / discharge cycles, capacity, rapid charge / discharge performance, cost, and the like.

  Electric double layer capacitors have been developed to meet this market need. Recently, electric double layer capacitors using activated carbon having a higher specific surface area have attracted attention.

  In addition, it can be applied to the high-capacity field such as the auxiliary power supply and uninterruptible power supply for electric vehicle batteries from the conventional low-power field, and in part, the regenerative energy during deceleration is charged to the capacitor and reversely discharged during acceleration. Passenger cars equipped with capacitors for the purpose of assisting engine output are now in the stage of reference exhibition.

  An electric double layer capacitor does not involve a chemical reaction like a normal secondary battery in charge and discharge. For this reason, compared with a secondary battery, internal resistance is remarkably low and large current discharge is possible. Furthermore, there is also a feature that there is no limit on the number of charge / discharge cycles. However, the biggest problem of the electric double layer capacitor is that the energy density is lower than that of the secondary battery, and various studies have been made to improve this point.

  For electric double layer capacitors, non-aqueous electrolytes in which an electrolyte such as quaternary ammonium salt or lithium perchlorate is dissolved in an organic polar solvent such as propylene carbonate, an aqueous sulfuric acid solution or an aqueous potassium hydroxide solution are used. There are roughly two types, one using such an aqueous electrolyte.

  When an aqueous electrolyte is used, the capacity of the electric double layer capacitor can be increased from about 1.3 to 2 times that when a non-aqueous electrolyte is used, and the internal resistance is further reduced from 1/5 to 1 /. Can be lowered to 10.

  The reason why the internal resistance can be lowered when using an aqueous electrolyte is due to the low electrical resistance of the aqueous electrolyte, but when using an aqueous electrolyte, the voltage must be reduced. Since it can only be raised to more than 1V, it also has the disadvantage that the amount of energy stored per volume is small.

On the other hand, when using the non-aqueous electrolyte energy stored per volume of the electric double layer capacitor in order to be able to raise the voltage of the electric double layer capacitor to more than the maximum 3V (power storage energy amount = CV ^2/2 (C: capacitor capacity, V: voltage) can be increased, and the nonaqueous electrolyte system is more advantageous from the viewpoint of increasing the energy density per volume.

  As the electrode active material of these electric double layer capacitors, activated carbon having a large specific surface area is considered to be optimal, and research on optimization of the electrode active material is actively conducted in various directions. The electrode active material of an electric double layer capacitor is usually a high specific surface area obtained by gas activation with water vapor, carbon dioxide, etc., starting from coconut shell, non-graphite carbon material (so-called hard carbon) such as coal and phenol resin It is manufactured using activated carbon.

That is, the pores formed by the decarbonization phenomenon caused by the reaction between the carbon material and water vapor or carbon dioxide are used. However, in order to obtain an electrode material for an electric double layer capacitor having a large capacitance, activated carbon having a BET method of 2000 m ² / g or more is required, and thus the activation yield is reduced to 20 wt% or less. Activation is required, increasing the production cost of the activated carbon obtained. Not only that, the bulk density of the activated carbon itself is low, and the bulk density as an electrode material cannot be increased.

Further, according to the measurement of the present inventor, 2000 m ² by the BET method using this as a raw material.
The electrostatic capacity of the electrode active material using activated carbon of / g in the non-aqueous electrolyte is about 30 F / g, and it is judged that there is still room for improvement in view of the specific surface area.

  As will be described later, this is considered to indicate that not all of the specific surface area represented by the BET formula is used for forming the electric double layer. That is, it is presumed that the formation of the electric double layer has an optimum pore size for the electrolyte used.

  For this reason, in the production of activated carbon, it is desired to develop a carbon material that is low in cost, has a high activation yield, and has a high capacity per volume, and the activated carbon obtained by activating it is used as an electric double layer. The use as an electrode material for capacitors has recently been studied and achieved results.

  An object of the present invention is to activate a carbon material obtained from inexpensive petroleum heavy oil and use it as an electrode active material of a non-aqueous electrolyte electric double layer capacitor, while having a large capacity. It is to provide a multilayer capacitor stably. Moreover, this invention is providing the electrode active material used for the electrode of the said non-aqueous electrolyte type electric double layer capacitor, the carbon material used as the raw material, and the precursor of this carbon material.

  When the activated carbon obtained by activating the obtained carbon material is used as the electric double layer capacitor electrode active material, the type of petroleum heavy oil, the heat treatment conditions, etc. The effects on characteristics were discussed in detail. As a result, it has been found that the characteristics of the electric double layer capacitor depend on the kind of heavy petroleum oil and the heat treatment conditions passed through the carbon material. For example, it has been found that when an atmospheric distillation residue oil and / or fluid catalytic cracking residue oil is used as a raw material and a heat treatment is performed under specific conditions, a large capacity can be obtained. The present invention has been made based on such knowledge.

That is, the present invention was obtained by maintaining a raw oil containing atmospheric distillation residue oil and / or fluid catalytic cracking residue oil as a main component at a pressure of 2.0 MPa or less and a temperature of 400 to 600 ° C. for 3 hours or more. It is a precursor of the carbon material used for the electrode active material for water electrolyte type electric double layer capacitors.
Furthermore, the present invention is a carbon material used as a raw material for an electrode active material used for a non-aqueous electrolyte electric double layer capacitor, obtained by heat-treating the precursor at 600 to 900 ° C., preferably 650 to 850 ° C. .
Furthermore, this invention is an electrode active material used for the electrode of the non-aqueous electrolyte type electric double layer capacitor obtained by activating the said carbon material. The activation performed here is general gas activation and chemical activation by alkali or the like, and preferably alkali activation by an alkali metal hydroxide.

  Moreover, this invention is a non-aqueous electrolyte type electric double layer capacitor using the said electrode active material.

  The present invention can provide a high-capacity non-aqueous electrolyte based electric double layer capacitor while using a carbon material obtained from a specific heavy petroleum oil as a raw material for the electric double layer capacitor electrode active material, And the electrode active material, carbon material and precursor thereof for use in the non-aqueous electrolyte-based electric double layer capacitor.

  In the present invention, atmospheric distillation residue oil and / or fluid catalytic cracking residue oil is used as a raw material. Furthermore, it is preferable to use these hydrodesulfurized oils. The atmospheric distillation residue oil is a residue oil obtained by atmospheric distillation of crude oil. The hydrodesulfurized oil of atmospheric distillation residue oil is a residue fraction obtained by directly hydrodesulfurizing (direct dehydration) of atmospheric distillation residue oil. Fluid catalytic cracking residue oil is usually decomposed by bringing heavy gas oil, vacuum gas oil, or atmospheric distillation residue oil into contact with a flowing powdered zeolite catalyst at about 430 to 550 ° C. to decompose gasoline fraction and light oil fraction. It refers to slurry oil or decanted oil by-produced from the generated fluid catalytic cracker. Examples of the hydrodesulfurized oil of the fluid catalytic cracking residue oil include desulfurized oil obtained by treating the slurry oil or decanted oil with a hydrodesulfurization apparatus. In addition, slurry oil or decanted oil obtained by processing a hydrodesulfurized raw material oil, for example, indirect desulfurized distillate oil, direct destilled distillate oil, etc. with a fluid catalytic cracking apparatus is also fluid catalytic cracking residual oil. Of hydrodesulfurized oil.

Furthermore, a mixed oil of atmospheric distillation residue oil and / or its hydrodesulfurized oil and fluid catalytic cracking residue oil and / or its hydrodesulfurized oil can also be used. In this case, it is desirable that the mixing ratio of the atmospheric distillation residue oil and / or its hydrodesulfurized oil is 70 vol% or less, preferably 60 vol% or less, more preferably the atmospheric distillation residue oil and / or its hydrogenation. The mixing ratio of desulfurized oil is 40 vol% or less. By using such a raw material to obtain a precursor of a carbon material and further heat-treating the precursor, a carbon material having a high orientation of a layered structure of a six-membered ring network plane can be obtained.
As the properties of the raw material oil mixed at the above ratio, it is desirable that the aromatic hydrocarbon component is 40 to 95 wt%, the resin content is 0.2 to 25 wt%, and the remaining coal is 0.1 to 10 wt%. More preferably, the aromatic hydrocarbon component is 45 to 95 wt%, the resin content is 0.5 to 20 wt%, and the residual carbon is 0.2 to 8 wt%. In particular, it is desirable that the aromatic hydrocarbon component is 50 to 90 wt%, the resin content is 1.0 to 15 wt%, and the remaining coal is 0.5 to 5 wt%.
Note that, as a raw material for the caulking process, a vacuum residue oil is also commonly used in the field of petroleum refining. However, in the present invention, the vacuum residue oil or its hydrodesulfurized oil is a desired carbon material for an electric double layer capacitor or the The precursor of the carbon material cannot be obtained.

  In order to obtain the precursor of the carbon material, the raw material oil is held at a pressure of 2.0 MPa or less and a temperature of 400 to 600 ° C. for 3 hours or more. During this time, the raw oil is pyrolyzed to produce coke, which is a precursor of the carbon material for electric double layer capacitors, together with light oil such as gas, cracked naphtha and cracked light oil. If the pressure, temperature and holding time are out of the range, a carbon material having a high orientation of the layered structure of the six-membered ring network plane cannot be obtained even if the obtained precursor is further heat-treated. Preferably, the coke which is a precursor is produced | generated by heat-processing on the conditions of pressure 0.4-1.0MPa, temperature 420-550 degreeC for 20 hours or more.

In order to produce a precursor of carbon material, as a device, a so-called tube bomb at the laboratory level, a delayed coker to produce a large amount of coke stably at a commercial level, and a bench of a delayed coker as an intermediate scale between the two. Various devices such as a reactor can be used.
Tube bombs are a common device used to produce needle coke at the laboratory level, such as heavy oils described in Mochida et al., Chemistry and Physics of Carbon, 24, 111 (1994). These can be used to produce cracked gas, cracked oil and relatively high quality coke (precursor of carbon material here) from heavy oil. This is an experimental device for producing coke by filling a steel can with raw material oil, connecting a gas discharge line to the top of the can, and inserting and holding the can in a heated sand bath. In this tube bomb, the reaction pressure can be arbitrarily set by the pressure gauge and the control valve of the gas discharge line, and the reaction pressure can be kept constant. Moreover, the reaction temperature is the set temperature of the sand bath, and the reaction time is the time from insertion into the sand bath until it is pulled out, both of which can be set arbitrarily.
When the reaction time (retention time) is different, the properties of the obtained coke are also slightly different. Therefore, the carbon material precursor used in the present invention is subjected to a heat history of 3 hours or more as the carbon material precursor.

  The delayed coker is an industrial thermal cracking apparatus for heavy oil, and produces cracked gas, cracked oil and relatively high quality coke (precursor of carbon material here) from heavy oil. The raw material oil is continuously sent to a heating furnace, rapidly heated in a short time, and supplied to the bottom of the coke drum. In the heat-insulated coke drum, carbonization proceeds under appropriate temperature and pressure, and coke generated from the liquid phase is accumulated to fill the drum. The cracked products (gas and cracked oil) are extracted from the top of the drum, sent to the rectification column, and fractionated. The heavy oil extracted from the bottom of the rectification tower is sent again to the heating furnace together with the raw material oil, and the above heat treatment is repeated. There are usually two coke drums, and when one is filled with coke, the feed oil is supplied by switching to an empty drum and processed as described above. On the other hand, after the drum filled with coke and separated is cooled, the accumulated coke is cut out with high-pressure water or the like.

Since coke (carbon material precursor) accumulates in the coke drum from the bottom to the top of the drum, the lower and upper cokes have different times of heat history (holding time) and can be obtained from each part. The characteristics of coke are also slightly different. Therefore, the carbon material precursor used in the present invention is one that has received a heat history of 3 hours or more. The carbon material precursor that has received a heat history of 3 hours or more can be identified from the amount of coke accumulated in the coke drum (the height of coke from the bottom of the drum) and the time required to reach that amount. . Specifically, from the upper surface of the coke accumulated in the coke drum, the one up to the coke height 3 hours before when the drum was filled with coke and the supply of the feedstock was stopped, and then the coke to the bottom of the drum Is cut out and used as a carbon material precursor.
As described above, the coke (carbon material precursor) obtained using a tube bomb or a delayed coker has a volatile content of 2 to 20 wt% and a hydrogen content of 1 to 6 wt% on a dry basis. desirable.

The obtained precursor is heat-treated at 600 to 900 ° C., preferably 650 to 850 ° C. for several tens of minutes to several hours in a firing furnace such as an atmospheric furnace, shuttle furnace, rotary kiln, tunnel furnace, etc., to obtain a carbon material. be able to.
Furthermore, the obtained carbon material can be activated to obtain activated carbon, that is, (electrode active material here), and this electrode active material can be suitably used for an electrode of an electric double layer capacitor. The activation performed here is general gas activation and chemical activation by alkali or the like, and among them, alkali activation by alkali metal hydroxide or the like expresses a high capacitance, which is preferable. The carbon material is preferably pulverized with a jet mill or the like before activation and classified with an airflow classifier or the like to form a powder with an average particle size of 10 to 15 μm. Although it can also grind | pulverize and classify after activation, the direction of activating a powdery carbon material rather than lump is uniformly activated. Moreover, after activating a powdery carbon material, you may grind | pulverize and classify again.

The electrode active material (activated carbon) thus obtained can be used for an electrode of an electric double layer capacitor and appropriately combined with a nonaqueous electrolyte to produce a nonaqueous electrolyte electric double layer capacitor. The nonaqueous electrolytic solution is not particularly limited as long as it can be usually used for an electric double layer capacitor. Preferred non-aqueous electrolytes include, for example, electrolytes such as quaternary ammonium borofluoride (for example, triethylmethylammonium borofluoride), lithium borofluoride, lithium perchlorate, etc., propylene carbonate, γ-butyl lactone, etc. Can be mentioned.
Moreover, what is necessary is just to produce an electrode by a well-known method. For example, powder obtained by pulverizing the electrode active material is mixed with a binder (binder, for example, polytetrafluoroethylene (PTFE), polyvinylidene chloride (PVDC), etc.), and the electrode material is formed into a sheet shape. Then, the electrode for a capacitor can be produced by pressure-bonding to the surface of a current collector such as an aluminum foil, and compression forming to increase the electrode density as necessary. An example of a capacitor electrode is shown in FIG. 1 as a schematic diagram. That is, each of the pair of electrode material sheets 4 formed as described above is pressure-bonded to the aluminum foil 2 and configured in a sandwich shape with the filter paper 5 containing the electrolytic solution in between. Further, the whole is sealed with an insulating polypropylene plate 1 using fastening means such as screws 6 and nuts 7. Conductive wires such as aluminum wires 3 are connected to the aluminum foil, and charging and discharging can be repeated with this.

  The carbon material obtained from the specific petroleum heavy oil obtained as described above can be activated to an appropriate specific surface area, and the obtained electrode active material has a large capacity per volume and a resistance value. Low material. However, easily graphitized carbon using coal as a raw material has a large amount of ash and crystallinity is too high. Therefore, when it is used as an electrode active material for a non-aqueous electrolyte electric double layer capacitor, there are problems such as gas generation and electrode expansion. Occur. Alternatively, when a chemically synthesized pitch or the like is used as a carbon source, there is a problem that costs are high.

  EXAMPLES Hereinafter, although this invention is demonstrated in detail based on an Example, this invention is not restrict | limited at all by the example which concerns.

  By using a tube bomb, using a mixed oil obtained by mixing an atmospheric distillation residue oil and a fluid catalytic cracking residue oil at 70:30 as a raw material oil, and holding at a pressure of about 0.5 MPa and about 500 ° C. for 40 hours, A precursor was obtained. The precursor was heated at a heating rate of 200 ° C. per hour in a nitrogen atmosphere to keep the furnace temperature at 700 ° C., held for 1 hour, and then cooled to room temperature by natural cooling to prepare a carbon material. . The carbon material was pulverized with a jet mill and classified with an airflow classifier to obtain a carbon material powder having an average particle size of 10 to 15 μm.

  Next, the carbon material powder was activated by the following procedure to obtain an electrode active material. That is, 2 parts by weight of potassium hydroxide was mixed with 1 part by weight of the carbon material powder, put into a nickel container, heated so as not to overflow from the container, and held at 750 ° C. for 2 hours. Then, after naturally cooling, the extracted mixture was repeatedly washed with water until pH 7 was obtained, whereby an electrode active material (activated carbon) was obtained.

The electrode active material thus obtained was added with 10 wt% of acetylene black as a conductive additive, 10 wt% of PTFE was added as a binder, rolled and formed into an electrode material sheet, and then pressed onto an aluminum foil to form an electrode. . As shown in FIG. 1, a filter paper 5 is used as a separator between the electrodes (in FIG. 1, the electrodes are shown separated from the electrode material sheet 4 and the aluminum foil 2), and the electrolyte contains 1M triethylmethylammonium borofluoride as the electrolyte. An electric double layer capacitor was prototyped using propylene carbonate, and the capacitance was measured, that is, the capacitance was evaluated. The results are shown in Table 1.
The capacitance is measured by charging the electric double layer capacitor cell produced above to a potential (2.5 to 3.0 V) at a current density of 1 mA / cm ^{2 so} that the potential difference between the ^two electrodes does not decompose the electrolyte. Here, the battery was charged up to 2.7 V, then held at 2.7 V for 1 hour, then discharged to 0 V at a current density of 1 mA / cm ² , and the capacitance was calculated.

  An electrode active material powder is obtained in the same manner as in Example 1 except that a mixed oil obtained by mixing atmospheric distillation residue oil and fluid catalytic cracking residue oil at 30:70 is used as a raw material oil. The capacity was evaluated. The results are shown in Table 1.

  An electrode active material powder was obtained in the same manner as in Example 1 except that fluid catalytic cracking residue oil was used as the raw material oil, electrodes were produced, and electrostatic capacity was evaluated. The results are shown in Table 1.

  A mixed oil obtained by mixing atmospheric distillation residue oil and fluid catalytic cracking residue oil at a ratio of 30:70 is used as a raw material oil. A holding time for obtaining a precursor of a carbon material is set to 60 hours, and then a heat treatment temperature of the precursor is set to 750. Except that the temperature was set to ° C., activated carbon as an electrode active material powder was obtained in the same manner as in Example 1, electrodes were prepared, and the capacitance was evaluated. The results are shown in Table 1.

  A mixed oil obtained by mixing an atmospheric distillation residue oil and a fluid catalytic cracking residue oil at a ratio of 30:70 is used as a raw material oil. A holding time for obtaining a precursor of a carbon material is set to 60 hours, and then a heat treatment temperature of the precursor is set to 650. Except that the temperature was set to ° C., activated carbon as an electrode active material powder was obtained in the same manner as in Example 1, electrodes were prepared, and the capacitance was evaluated. The results are shown in Table 1.

  A mixed oil obtained by mixing atmospheric distillation residue oil and fluid catalytic cracking residue oil at 50:50 is used as a raw material oil, and a holding time for obtaining a carbon material precursor is set to 40 hours, and then a heat treatment temperature of the precursor is set to 700 ° C. The activated carbon of the electrode active material powder was obtained in the same manner as in Example 1, electrodes were prepared, and the capacitance was evaluated. The results are shown in Table 1.

Comparative Example 1

  Using a tube bomb, a vacuum distillation residue oil was used as a raw material oil, and a pressure of about 0.5 MPa was maintained at about 500 ° C. for 30 hours to obtain a carbon material precursor. The precursor is heated at a heating rate of 200 ° C. per hour in a nitrogen atmosphere to keep the temperature in the furnace at 700 ° C. and heat treated for 1 hour, and then cooled to room temperature by natural cooling to create a carbon material. did. The carbon material was pulverized with a jet mill and classified with an airflow classifier to obtain a carbon material powder having an average particle size of 10 to 15 μm.

  Next, the carbon material powder was activated by the following procedure. That is, 2 parts by weight of potassium hydroxide was mixed with 1 part by weight of the carbon material powder, put into a nickel container, heated so as not to overflow from the container, and held at 750 ° C. for 2 hours. Then, after naturally cooling, the extracted mixture was repeatedly washed with water until pH 7 was obtained, whereby activated carbon (electrode active material) was obtained.

  The electrode active material thus obtained was added with 10 wt% acetylene black as a conductive assistant, 10 wt% PTFE was added as a binder, and after rolling and forming, the electrode was pressed onto an aluminum foil. As shown in FIG. 1, a filter paper is used as a separator between the positive and negative electrodes, and an electric double layer capacitor is manufactured using propylene carbonate containing 1M triethylmethylammonium borofluoride as an electrolyte, and the capacitance is measured. went. The results are shown in Table 1.

Comparative Example 2

  An electrode active material powder was obtained in the same manner as in Example 1 except that petroleum tar was used as the raw material oil, an electrode was prepared, and the capacitance was evaluated. The results are shown in Table 1.

Comparative Example 3

  A mixed oil obtained by mixing an atmospheric distillation residue oil and a fluid catalytic cracking residue oil at 30:70 is used as a raw material oil. A holding time for obtaining a carbon material precursor is set to 40 hours, and then a heat treatment temperature of the precursor is set to 1000 ° C. In the same manner as in Example 1, an electrode active material powder was obtained, an electrode was prepared, and the capacitance was evaluated. The results are shown in Table 1.

Comparative Example 4

  An electrode was prepared in the same manner as in Example 1 except that a mixed oil obtained by mixing atmospheric distillation residue oil and fluid catalytic cracking residue oil at 30:70 was used as the raw material oil, and the holding time for obtaining the carbon material precursor was 2 hours. An active material powder was obtained, an electrode was prepared, and the capacitance was evaluated. The results are shown in Table 1.

FIG. 1 shows an outline of the prototype electric double layer capacitor as an exploded view.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Polypropylene board 2 Aluminum foil 3 Aluminum wire 4 Electrode material sheet 5 Filter paper 6 Screw 7 Nut

Claims (4)

  A non-aqueous electrolyte-based electric oil obtained by holding a raw oil mainly containing atmospheric distillation residue oil and / or fluid catalytic cracking residue oil at a pressure of 2.0 MPa or less and a temperature of 400 to 600 ° C. for 3 hours or more. Carbon material precursor used for electrode active materials for multilayer capacitors.   A raw material oil containing atmospheric distillation residue oil and / or fluid catalytic cracking residue oil as a main component is maintained at a pressure of 2.0 MPa or less and a temperature of 400 to 600 ° C. for 3 hours or more to obtain a precursor of a carbon material, A carbon material obtained by heat-treating the body at 600 to 900 ° C. and used as a raw material for an electrode active material used for a non-aqueous electrolyte based electric double layer capacitor.   A raw material oil containing atmospheric distillation residue oil and / or fluid catalytic cracking residue oil as a main component is maintained at a pressure of 2.0 MPa or less and a temperature of 400 to 600 ° C. for 3 hours or more to obtain a precursor of a carbon material, The electrode active material used for the electrode of the non-aqueous-electrolyte system electric double layer capacitor obtained by heat-processing a body at 600-900 degreeC, obtaining a carbon material, and further activating this carbon material. A raw material oil containing atmospheric distillation residue oil and / or fluid catalytic cracking residue oil as a main component is maintained at a pressure of 2.0 MPa or less and a temperature of 400 to 600 ° C. for 3 hours or more to obtain a precursor of a carbon material, A non-aqueous electrolyte type electric double layer capacitor using an electrode active material obtained by heat treating a body at 600 to 900 ° C. to obtain a carbon material and further activating the carbon material.