JP2018041801A - Electrode structure, capacitor and method for manufacturing electrode structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrode structure, a capacitor and a method for manufacturing the electrode structure which enable the further increase in energy density.SOLUTION: A capacitor 10 is a lithium ion capacitor, in which an electrode structure 14 has current collectors 19, 21 formed by a porous metal, and an electrode material provided in each of the current collectors 19, 21. The electrode material includes an active substance, a conductive assistant and a binder; active carbon, carbon nanotube, graphene or the like can be used as the active substance. The concentration of the binder is 0.1-9 wt.%. The current collectors are each composed of a sintered compact in which metal particles bind to one another, and they are preferably 60%-99% in porosity.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an electrode structure, a capacitor, and a method for manufacturing the electrode structure, and more particularly to an electric double layer capacitor (EDLC) and a lithium ion capacitor (LiC).

  The electric double layer capacitor and the lithium ion capacitor have been increased in capacity by using an electrode in which an active material is filled in a current collector formed of a porous metal (for example, Patent Documents 1 and 2). . In Patent Document 1, lithium ions are occluded by a chemical method or an electrochemical method in a positive electrode composed of a polarizable electrode material mainly composed of activated carbon and a current collector, and a carbon material that occludes and desorbs lithium ions. An electric double layer capacitor characterized by having a negative electrode composed of a carbonaceous material and a porous metal current collector that does not form an alloy with lithium, and a non-aqueous electrolyte containing a lithium salt is disclosed.

  In Patent Document 2, a polarizable electrode material containing activated carbon powder, conductive material powder, and a binder is combined with a collector of stainless steel fibers in a mixed state to form a positive electrode, and the activated carbon powder, conductive powder, and binder are combined. A polarizable electrode material is combined with a metal current collector to form a negative electrode, a separator is disposed between the positive electrode and the negative electrode, and the positive electrode, the negative electrode, and the separator are impregnated with a non-aqueous electrolyte. An electric double layer capacitor is disclosed.

JP-A-9-55342 (Claim 1) JP-A-9-232190 (Claim 1)

  However, in Patent Documents 1 and 2, since the amount of the binder is large, a sufficient amount of active material cannot be filled in the electrode, resulting in a problem that the amount of active material per unit volume decreases and the energy density decreases. It was. Since the binder functions to bind the current collector and the active material, it needs to be included in the electrode material to some extent.

  An object of this invention is to provide the manufacturing method of the electrode structure which can make energy density higher, a capacitor, and an electrode structure.

  A first aspect of the present invention is an electrode structure having a current collector formed of a porous metal and an electrode material provided in the current collector, the electrode material comprising an active material, a conductive material An auxiliary agent and a binder are included, and the concentration of the binder in the electrode material is 0.1 wt% or more and 9 wt% or less.

  A second aspect of the present invention is the invention based on the first aspect, wherein the current collector is a sintered body in which a plurality of metal particles are bonded and has a porosity of 60% or more and 99% or less. It is characterized by that.

  A third aspect of the present invention is an invention based on the first or second aspect, wherein the electrode structure has a thickness of 100 μm or more and 5000 μm or less.

  A fourth aspect of the present invention is the invention based on any one of the first to third aspects, wherein the electrode material has a concentration of the conductive auxiliary of 0.1 wt% or more and 9 wt% or less. It is characterized by that.

  According to a fifth aspect of the present invention, there is provided an electrode structure based on any one of the first to fourth aspects.

  A sixth aspect of the present invention is a method of manufacturing an electrode structure in which an electrode material including an active material, a conductive additive, and a binder is provided on a current collector formed of a porous metal, the electrode A concentration of the binder in the material is 0.1 wt% or more and 9 wt% or less, and the current collector is filled with a slurry containing the electrode material and a solvent and having a viscosity of 0.1 Pa · s to 30 Pa · s. A process is provided.

  Since the electrode structure according to the first aspect of the present invention can increase the amount of active material by reducing the amount of binder, the energy density per unit volume can be increased. In addition, since the amount of the binder can be reduced, the extent to which the binder covers the surface of the active material can be reduced, and the capacitance per unit mass of the active material can be increased.

  The electrode structure according to the second aspect of the present invention has a porosity of 60% to 99%, so that the electrode material can be sufficiently filled.

  The electrode structure according to the third aspect of the present invention can increase the density of the electrodes.

  In the electrode structure according to the fourth aspect of the present invention, the contact between the conductive additive and the active material is maintained, and the cycle characteristics can be improved.

  Since the capacitor according to the fifth aspect of the present invention can increase the amount of the active material by reducing the amount of the binder, the energy density per unit volume can be increased. In addition, since the amount of the binder can be reduced, the extent to which the binder covers the surface of the active material can be reduced, and the capacitance per unit mass of the active material can be increased.

  The electrode structure manufacturing method according to the sixth aspect of the present invention can more reliably manufacture an electrode structure having a high energy density per unit volume.

It is a disassembled perspective view which shows the structure of the electric double layer capacitor which concerns on this embodiment.

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

1. Embodiment (Configuration of Capacitor)
A capacitor 10 that is an electric double layer capacitor or a lithium ion capacitor shown in FIG. 1 includes an outer container 12, an electrode structure 14, a separator 16, and an electrolyte (not shown) disposed in the outer container 12. Is provided. The outer container 12 is formed of a rectangular metal sheet material. The electrode structure 14 includes a positive electrode 18 and a negative electrode 20, and a terminal 22 is provided for each. The electrode structure 14 preferably has a thickness of 100 μm to 5000 μm. Thereby, the electrode structure 14 can make the density of an electrode high. The capacitor 10 is sealed in a state in which the electrode structure 14, the separator 16, and the electrolytic solution are accommodated in the outer container 12 and only one end portion of the terminal 22 is exposed to the outside. The positive electrode 18 and the negative electrode 20 are referred to as an electrode structure 14 unless otherwise distinguished.

(Configuration of electrode)
The positive electrode 18 includes a current collector 19 and an electrode material provided in the current collector 19. The current collector 19 is made of a porous metal. In the present embodiment, the current collector 19 is formed of a sintered body in which a plurality of metal particles are bonded, and has a three-dimensional network structure. The current collector 19 has a skeleton formed of metal and a space surrounded by the skeleton. The space is continuous in the current collector 19.

  The porosity of the current collector 19 is preferably 60% to 99%. The current collector 19 can be sufficiently filled with the electrode material if the porosity is 60% or more. The porosity means the ratio of the volume of the space in the current collector 19 to the total volume of the current collector 19. The porosity can be determined by the Archimedes method by measuring the weight of the current collector 19 in the air and the weight in water.

  When the capacitor 10 is an electric double layer capacitor, the same positive electrode and negative electrode can be used. As a metal forming the current collector 19 of the positive electrode 18, aluminum can be mainly used. The electrode material includes an active material, a conductive additive, and a binder. As the active material, activated carbon, carbon nanotube, graphene, or the like can be used. As the conductive assistant, carbon black such as acetylene black (AB) and ketjen black (KB), vapor grown carbon fiber (VGCF), graphite, and the like can be used. As the binder, polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), ethylene-propylene-diene copolymer (EPDM), styrene-butadiene rubber (SBR), or the like can be used. The concentration of the conductive assistant is preferably 0.1 wt% or more and 9 wt% or less.

When the capacitor 10 is a lithium ion capacitor, the positive electrode 18 can be the same as the electric double layer capacitor, but the negative electrode 20 includes a current collector 21 and an electrode provided in the current collector 21. Material. The current collector 21 has the same configuration as the positive electrode 18 except that only the metal is different. As a metal forming the current collector 21 of the negative electrode 20, aluminum, copper, stainless steel, or the like can be used. The electrode material includes an active material, a conductive additive, and a binder. Examples of the active material include silicon (Si), silicon oxide (SiO), tin (Sn), tin-cobalt compound (Sn—Co), stannic oxide (SnO ₂ ), natural graphite, artificial graphite, and lithium titanate ( Li ₄ Ti ₅ O ₁₂ ) or the like can be used. As the conductive assistant, the same material as that of the positive electrode 18 can be used. As the binder, polyvinylidene fluoride (PVDF), styrene butadiene rubber (SBR), carboxymethyl cellulose (CMC), or the like can be used.

The electrolytic solution includes an electrolyte and a solvent. When the capacitor 10 is an electric double layer capacitor, tetraethylammonium tetrafluoroborate (Et ₄ NBF ₄ ) and triethylmethylammonium tetrafluoroborate (Et ₃ MeNBF ₄ ) are generally used as the electrolyte. The solvent is generally propylene carbonate (PC).

When the capacitor 10 is a lithium ion capacitor, a lithium salt such as LiPF ₆ , LiBF ₄ , or LiClO ₄ can be used as a solute that is an electrolytic solution. As the solvent, a non-aqueous solvent containing EC (ethylene carbonate), DEC (diethyl carbonate), DMC (dimethyl carbonate), MEC (methyl ethyl carbonate), or the like can be used.

(Production method)
The electrode structure 14 can be manufactured by a process of producing the current collectors 19 and 21, a process of producing an electrode slurry, and a process of filling and drying the electrode slurry in the current collectors 19 and 21. In addition, the manufacturing method shown below is an example, Comprising: It does not restrict to this.

  First, a process for producing the current collectors 19 and 21 will be described. A metal fine powder, a water-soluble binder, a surfactant, and a foaming agent are mixed with water to prepare a slurry. Next, by a doctor blade method, the slurry is thinly applied onto a pet film and formed into a sheet shape. The molded sheet is heated to a predetermined temperature, and dried while forming bubbles on the sheet with a foaming agent. Thereafter, sintering is performed in a non-oxidizing atmosphere (for example, an inert atmosphere or a reducing atmosphere) at a predetermined temperature to form a sintered body in which a plurality of metal particles are bonded, and the aggregate formed by the sintered body. Electrical bodies 19 and 21 are obtained.

  Next, the process of producing the electrode slurry will be described. The binder is dissolved in an organic solvent. It is preferable that the binder has a concentration of 0.1 wt% or more and 9 wt% or less with respect to the active material and the conductive additive. When the binder concentration is within the above range, the contact between the conductive additive and the active material is maintained, so that the capacitor 10 can improve cycle characteristics.

  The concentration of the binder is adjusted so that it is more preferably 0.1 wt% or more and 5.0 wt% or less, and further preferably 0.1 wt% or more and 3.0 wt% or less. The mixed liquid, the active material and the conductive auxiliary powder are mixed using a planetary mixer, a ball mill, a Henschel mixer, or the like to obtain an electrode slurry. The electrode slurry is adjusted to have a higher viscosity than before. In the case of the present embodiment, the viscosity of the electrode slurry is 0.1 Pa · s to 30 Pa · s, more preferably 1 to 10 Pa · s. In the case of an organic binder such as PVDF, the viscosity of the electrode slurry can be adjusted by adjusting the amount of the organic solvent or by adding CMC as a thickener. Here, 1 Pa · s is 1000 cps. In the present specification, the viscosity is a viscosity measured at 25 ° C. and 30 rpm using a rotary viscometer (manufactured by Brookfield, model: DV1).

  Subsequently, a process of filling and drying the electrode slurry in the current collectors 19 and 21 will be described. The electrode slurry can be filled into the current collectors 19 and 21 by being applied to the current collectors 19 and 21. The active material can be filled into the metal porous body even using the technique described in JP-A-2015-22916. Then, it is left to dry in a 120 ° C. drying oven for 3 hours.

  Thus, the electrode structure 14 according to the present embodiment can be obtained. Further, the electrode structure 14 may be rolled as desired. Thereby, since the porosity of the electrode structure 14 decreases, the electrode density can be increased.

(Function and effect)
The electrode structure 14 according to the present embodiment has a smaller amount of binder in the electrode material than the conventional one, but the current collectors 19 and 21 are adjusted by adjusting the viscosity of the electrode slurry to 0.1 Pa · s to 30 Pa · s. Can be filled with an electrode material. As a result, the electrode structure 14 can increase the amount of the active material by reducing the amount of the binder. Therefore, the capacitor 10 can increase the energy density per unit volume.

The energy density is the capacitance per unit volume (F / cm ³ ), that is, the capacitance per unit mass of the actually measured active material (F / g) × the active material density in the electrode (g / cm ³ ) Evaluation can be made with the value obtained by

  In the electrode structure 14, the amount of the binder in the electrode material is reduced, so that the binder is less likely to swell due to the electrolytic solution. For this reason, since the electrode structure 14 maintains the internal space, the content of the electrolytic solution increases. Thereby, it is considered that the capacitor 10 is less likely to increase in internal resistance.

  Although the electrode structure 14 has a small amount of binder, the current collectors 19 and 21 are formed of a porous metal, so that the current collectors 19 and 21 are formed even when the active material expands and contracts due to charge and discharge. Can hold active material. Accordingly, the electrode structure 14 can keep the contact between the active material and the conductive additive, thereby preventing the cycle characteristics from being deteriorated.

  In the experiment described later, it was confirmed that the capacitor 10 increased in capacitance per unit mass of the active material by reducing the binder amount. The capacitor 10 is considered to be due to the fact that the binder layer formed by attaching the binder to the surface of the active material is thinned by reducing the amount of the binder, and the pores of the active material exposed to the electrolytic solution are increased. As described above, the capacitor 10 of this embodiment has an effect of increasing the capacitance of the active material itself by reducing the amount of the binder. In other words, the amount of the active material of the capacitor 10 is increased by reducing the amount of the binder, but the capacitance per unit mass of the active material increases more than the increase of the capacitance due to the increase of the active material. I was able to confirm that.

  Incidentally, it is known that the electric double layer capacitor has pores on which the ions are adsorbed on the surface of the active material, and the number of pores is proportional to the capacitance. When the amount of the binder is large, it is expected that a part of the pores is blocked. In addition, a general electric double layer capacitor using a current collector using aluminum foil has a binder amount in order to bind a binder containing an active material and a composite layer containing a conductive additive to the aluminum foil. Is difficult to reduce.

  The capacitor 10 can reduce the electrode resistance. In the electrode structure 14, it is considered that the physical distance between the particles constituting the active material is reduced due to the reduction in the binder amount, and as a result, the electrode resistance is reduced.

(Modification)
In the case of the above embodiment, the current collectors 19 and 21 have been described as being porous metals made of a sintered body in which a plurality of metal particles are bonded, but the present invention is not limited thereto. For example, the current collector may be a porous metal formed by plating a porous substrate such as urethane foam with a metal and then removing the substrate. The current collector may be a porous metal made of a nonwoven fabric of metal fibers.

2. Example According to the above procedure, a sample of an electrode structure was prepared and the electrode structure was evaluated. As the current collector, two types of sintered bodies were made of aluminum and copper. The sintered body of aluminum is composed of 200 g of fine aluminum powder (Aldrich, average particle size 5 μm), 50 g of polyvinyl alcohol (Nippon Acetate / Poval) as a water-soluble binder, and a water-soluble surfactant. A slurry was prepared by mixing 6 g (manufactured by Kao Corporation, product name: Emar, product number 20T), 5 g of hexane (manufactured by Kanto Chemical Co., Ltd.) as a foaming agent, and 500 mL of water. By the doctor blade method, the produced slurry was thinly applied onto a pet film (manufactured by Toray Industries, Inc., product name: Treffan, product number 2500T) and formed into a sheet shape. The molded sheet was dried while heating to 50 ° C. to form bubbles in the sheet. Thereafter, the molded body was peeled off from the pet film, placed on an alumina plate, and sintered in an argon atmosphere at 500 ° C. to obtain porous aluminum having a porosity of 94% and a thickness of 0.4 mm. The produced porous aluminum was cut into a width of 10 mm and a length of 30 mm to prepare a porous aluminum skeleton. The porous pore size was changed by changing the bubble formation time during production. Moreover, the porosity of the porous body was changed by changing the amount of aluminum fine powder added.

  The copper sintered body is made of a fine powder of copper (manufactured by Aldrich, average particle size 10 μm), and a slurry is prepared in the same manner as in the case of the aluminum, and the sintering temperature is changed to 1000 ° C. with porous copper. A skeleton was produced.

  For the electrode slurry, PVDF and polyimide, which are organic binders, add NMP (N-methyl-2-pyrrolidone) as an organic solvent to dissolve the binder, and further add the powder of the active material and the conductive auxiliary agent. It melt | dissolved with the mixer and adjusted the quantity of the organic solvent, and obtained the slurry for electrodes whose viscosity is 0.1 Pa.s-30 Pa.s.

  The prepared electrode slurry was applied to the sintered body and dried at 120 ° C. for 60 minutes. Then, it cut | disconnected to the magnitude | size of width 20mm and length 25mm, and obtained the electrode structure. Here, a masking tape was applied to a 5 mm portion in a length of 25 mm, the slurry was not applied, and a lead wire was attached to this portion by spot welding after drying. Tables 1 and 2 show the specifications of the electrode structure.

Examples 1-28 and Comparative Examples 1-4 are positive electrodes of electric double layer capacitors, and activated carbon was used as an active material. Moreover, the same electrode as the positive electrode whose active material is activated carbon was used for the negative electrode. A cellulose non-woven fabric was used as a separator, cut out larger than the electrode structure, and sandwiched between the positive electrode and the negative electrode. After insertion into the aluminum laminate pack, 1M Et ₄ NBF ₄ or 1M Et ₃ MeNBF ₄ dissolved in propyne carbonate (PC) solvent was injected to produce a cell. Electrical characteristics were measured with a charge / discharge test apparatus (manufactured by Asuka Electronics Co., Ltd., model: ACD-R1APS). Charging was performed by a CC-CV (constant current constant voltage) system of 10C-2.4V. Discharging was performed by a CC (constant current) method with a constant 10C rate and a cut-off voltage of 0V. After 20 cycles, the resistance value was measured in the discharged state. As a result of the electrical characteristics, voltage (V) is taken on the y-axis and current capacity (mAh / g) is taken on the x-axis, and the electrostatic capacity (F / g) per unit mass of the active material is obtained from the slope. . At this time, the mass as the denominator is only activated carbon, and does not include the mass of the binder and the conductive additive. Moreover, the electrostatic capacitance per unit volume was calculated | required using the result of the electrostatic capacitance per unit mass (F / g) of an active material as above-mentioned. The results are shown in Tables 1 and 3.

Examples 29 to 42 and Comparative Examples 5 and 6 are negative electrodes of lithium ion capacitors, and Li ₄ Ti ₅ O ₁₂ or graphite was used as an active material. Moreover, the electrode whose active material is activated carbon was used for the positive electrode. In Examples 29 to 35 and Comparative Example 5 using Li ₄ Ti ₅ O ₁₂ as an active material, a cellulose nonwoven fabric was used as a separator, cut out larger than the electrode structure, and sandwiched between a positive electrode and a negative electrode. After being inserted into the aluminum laminate pack, an electrolytic solution in which 1M LiPF ₆ was dissolved in an ethylene carbonate (EC) solvent was injected to produce a cell. The discharge characteristics were measured with a charge / discharge test apparatus (manufactured by Asuka Electronics Co., Ltd., model: ACD-R1APS). Charging was performed by a CC-CV (constant current constant voltage) system of 5C-3.0V. Discharge was performed by a CC (constant current) method with a constant 5C rate and a cut-off voltage of 1.5V. After 10 cycles, the resistance value was measured in the discharged state.

In Examples 36 to 42 and Comparative Example 6 using graphite as an active material, a cellulose nonwoven fabric was used as a separator, cut out larger than the electrode structure, and sandwiched between a positive electrode and a negative electrode. After being inserted into the aluminum laminate pack, an electrolyte solution in which 1M LiBF ₄ was dissolved in propylene carbonate (PC) was injected to produce a cell. The discharge characteristics were measured with a charge / discharge test apparatus (manufactured by Asuka Electronics Co., Ltd., model: ACD-R1APS). Charging was performed by a CC-CV (constant current constant voltage) system of 5C-3.8V. Discharge was performed by a CC (constant current) method with a constant 5C rate and a cut-off voltage of 1.0V. After 10 cycles, the resistance value was measured in the discharged state.

  With respect to the results of the characteristics during discharge, voltage (V) was taken on the y-axis and current capacity (mAh / g) was taken on the x-axis. The results are shown in Tables 2 and 4.

  As a negative electrode for a lithium ion capacitor, the characteristics when lithium titanate and graphite were used as active materials were also compared by changing the amount of binder. The resistance value was measured by sandwiching a separator between the same two negative electrodes.

  In the above table, since the resistance change rate tends to increase as the electrode becomes thicker, the resistance value of a sample (comparative example) with a binder of 10 wt% is set to 100 under each condition. The change in internal resistance was expressed as a percentage. The resistance value is an actual resistance value of a DC component measured by an AC impedance method when the frequency is 0.01 Hz.

  From the results shown in this table, it was confirmed that in each of the samples according to the examples where the amount of the binder was smaller than that of the comparative example, the capacitance per unit mass of the active material increased and the internal resistance decreased. . From this, the sample according to the example is formed by the binder covering the active material by reducing the amount of the binder, increasing the capacitance per unit mass due to the increase of the active material that touches the electrolytic solution. It is thought that the internal resistance was lowered by the thinning of the layer.

  The capacitance per unit mass of the active materials of Examples 1 to 7 is larger than 17.1 F / g of Comparative Example 1, and increases as the amount of the binder decreases by about 10%. Increased to 0.0 F / g. In Examples 1 to 7, since the amount of binder is small, the amount of binder adhering to the activated carbon surface is reduced, and the number of pores on the activated carbon surface that is blocked by the binder is reduced. It is thought that the capacity has increased. Moreover, in Examples 1-7, the effect that the resistance of an electrode falls by the reduction of a binder was also acquired. The resistance change rate (%) of each Example when the resistance value when the binder amount of Comparative Example 1 is 10 wt% is 100 is shown in the table. A binder has a role which connects activated carbon, a conductive support agent, and a porous metal, and is an insulator fundamentally. In Examples 1 to 7, the physical distance between the activated carbon, the conductive additive, and the metal porous body is reduced due to the reduction of the binder amount, and the internal resistance is expected to be reduced.

  In Examples 8 to 14, the binder is an SBR + CMC system, and the electrostatic capacity is larger than 21.6 F / g of Comparative Example 2 and increases as the amount of the binder is reduced. It has increased to g. In Example 8, the binder amount was 0.1 wt%, and the resistance change rate when the resistance value of Comparative Example 2 having 10 wt% was set to 100 was reduced to 86.9.

  In conventional electric double layer capacitors (EDLC), aluminum foil is used for the current collector of the electrode, and the amount of binder can be reduced in order to maintain the binding between the electrode layer containing activated carbon and the aluminum foil. Therefore, it was not possible to confirm an increase in capacitance due to a reduction in the binder amount.

  In Examples 15 to 21, the binder is Teflon (registered trademark), the capacitance is larger than 12.8 F / g of Comparative Example 3, and the increase in the capacitance of the activated carbon due to the reduction of the binder amount is confirmed. I was able to. In Examples 22 to 28, it can be confirmed that the binder was polyimide and the capacitance was increased compared to 15.4 F / g of Comparative Example 4. As described above, even when the binder was Teflon (registered trademark) or polyimide, an increase in electrostatic capacity and a decrease in internal resistance could be confirmed.

In Examples 29 to 35, lithium titanate (Li ₄ Ti ₅ O ₁₂ ) was used as the negative electrode active material, and aluminum was used as the porous metal of the negative electrode. In Examples 29 to 35, as compared with Comparative Example 5, the discharge capacity per active material increased and the internal resistance of the electrode also decreased as the amount of binder decreased.

  In Examples 36 to 42, graphite was used for the negative electrode active material and copper was used for the negative electrode porous metal. In Examples 36 to 42, as compared with Comparative Example 6, the discharge capacity per active material increased and the internal resistance decreased as the amount of binder was reduced.

From the above results, the binder greatly affects the capacitance of the activated carbon depending on the type and amount, and adjusting the type or amount may increase the capacitance of the capacitor or decrease the internal resistance. it can.

10 Lithium ion capacitor (capacitor)
14 Electrode structure 18 Positive electrode (electrode structure)
19, 21 Current collector 20 Negative electrode (electrode structure)

Claims (6)

A current collector formed of a porous metal;
An electrode structure having an electrode material provided in the current collector,
The electrode material includes an active material, a conductive additive, and a binder, and the concentration of the binder in the electrode material is 0.1 wt% or more and 9 wt% or less. 2. The electrode structure according to claim 1, wherein the current collector is a sintered body in which a plurality of metal particles are bonded, and has a porosity of 60% to 99%. The electrode structure according to claim 1 or 2, wherein the electrode structure has a thickness of 100 µm or more and 5000 µm or less. 4. The electrode structure according to claim 1, wherein the electrode material has a concentration of the conductive auxiliary of 0.1 wt% or more and 9 wt% or less. A capacitor comprising the electrode structure according to claim 1. A method of manufacturing an electrode structure in which an electrode material including an active material, a conductive additive, and a binder is provided on a current collector formed of a porous metal,
A concentration of the binder in the electrode material is 0.1 wt% or more and 9 wt% or less;
The manufacturing method of the electrode structure characterized by providing the said collector with the slurry which contains the said electrode material and a solvent, and has a viscosity of 0.1 Pa.s-30 Pa.s.

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