JP2008130999A - Electrochemical element and manufacturing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrochemical element capable of reducing the internal resistance, while increasing the capacity per unit volume (unit weight), and to provide a manufacturing method therefor. <P>SOLUTION: The electrochemical element includes a collector 11, a first active carbon electrode layer 12A provided on the collector 11, and a second active carbon electrode layer 12B provided on the first electrode layer 12A. The first active carbon electrode layer 12A is constituted of active carbon, a conductive material and a binding material, and the second active carbon electrode layer 12B is constituted of active carbon, a conductive material and a binding material. The content ratio Y of the conductive material, contained in the second layer 12B, is larger than a content ratio X of the conductive material contained in the first layer 12A. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electrochemical element in which an electrode having a multilayer structure is provided on a current collector, and a method for producing the electrochemical element.

  Conventionally, in portable devices and in-vehicle electric devices, it has been studied to use power storage devices such as electric double layer capacitors and hybrid capacitors that can be charged and discharged more rapidly than secondary batteries. On the other hand, since the capacity | capacitance of such an electrical storage device is smaller than the capacity | capacitance of a secondary battery, the high capacity | capacitance of an electrical storage device is requested | required.

  Here, in order to increase the capacity of the electricity storage device, a method of laminating an electrode unit including a current collector, an activated carbon electrode, an electrolytic solution, and a separator, a method of rolling the electrode unit, and the like can be considered. However, these methods do not improve the capacity per unit volume or the unit weight of the activated carbon electrode.

  In order to increase the amount of activated carbon contained in the activated carbon electrode, a method of forming a multilayer structure of the activated carbon electrode by repeatedly applying and drying activated carbon or a conductive material (for example, carbon black) can be considered.

  For example, as a secondary battery electrode, there has been proposed a technique for reducing the charging time by multilayering activated carbon electrodes and changing the average porosity of each activated carbon electrode layer (for example, Patent Document 1). In addition, a technique for improving the impregnation property of the electrolytic solution by sandwiching a conductor layer between activated carbon electrode layers has been proposed (for example, Patent Document 2).

Japanese Patent Laying-Open No. 2003-77542 (for example, claim 1) Japanese Patent Application Laid-Open No. 2004-87824 (for example, claim 1, FIG. 1, etc.)

  In order to increase the amount of activated carbon contained in the activated carbon electrode, increasing the thickness of the activated carbon electrode by multilayering or the like increases the electrical resistance of the activated carbon electrode. Therefore, the activated carbon electrode with increased thickness is not suitable for applications that require high output.

  On the other hand, when the content ratio of the conductive material included in the activated carbon electrode is increased in order to reduce the electric resistance of the activated carbon electrode, the content ratio of the activated carbon included in the activated carbon electrode is decreased. As a result, an increase in capacity of the activated carbon electrode cannot be realized.

  In addition, the activated carbon electrode which changed the average porosity of each activated carbon electrode layer is not suitable for the use which requires high output, since the electrical resistance of an activated carbon electrode increases with a space | gap. Moreover, since the conductor which does not contribute to high capacity | capacitance is provided, the capacity | capacitance per unit volume (unit weight) will fall in the activated carbon electrode which pinched | interposed the conductor layer between the activated carbon electrode layers.

  Therefore, the present invention has been made to solve the above-described problems, and an electric storage device that can reduce internal resistance while increasing the capacity per unit volume (unit weight). It is an object of the present invention to provide an electrochemical element and a method for producing the electrochemical element.

  The first feature of the present invention includes a current collector, a first activated carbon electrode layer provided on the current collector, and a second activated carbon electrode layer provided on the first activated carbon electrode layer. In the electrochemical element, the first activated carbon electrode layer is composed of activated carbon, a conductive material and a binder, and the second activated carbon electrode layer is composed of activated carbon, a conductive material and a binder, and the first activated carbon electrode The conductive material included in the layer is the same as the conductive material included in the second activated carbon electrode layer, and the content ratio Y of the conductive material included in the second activated carbon electrode layer is included in the first activated carbon electrode layer. The gist is that it is larger than the content ratio X of the conductive material.

  Here, the distance between the second activated carbon electrode layer and the current collector is longer than the distance between the first activated carbon electrode layer and the current collector. Therefore, the electrical resistance between the second activated carbon electrode layer and the current collector is generally larger than the electrical resistance between the first activated carbon electrode layer and the current collector.

  According to the above-described feature, when the content ratio Y of the conductive material contained in the second activated carbon electrode layer is larger than the content ratio X of the conductive material contained in the first activated carbon electrode layer, the thickness of the activated carbon electrode is increased. Even so, an increase in the electrical resistance of the activated carbon electrode can be suppressed. On the other hand, since the activated carbon electrode has a multilayer structure, it is possible to increase the thickness of the activated carbon electrode and increase the capacity per unit volume (unit weight).

  The second feature of the present invention is that, in the first feature described above, the property of being soluble in the solvent of the binder contained in the first activated carbon electrode layer is that the solvent of the binder contained in the second activated carbon electrode layer. The gist is that it is different from the property of being soluble in water.

  According to a third feature of the present invention, in the first feature or the second feature described above, the conductive material contained in the first activated carbon electrode layer and the second activated carbon electrode layer is carbon black, and the content ratio is The gist is that X and the content ratio Y satisfy all the relationships of X ≧ 1, 3 ≦ Y ≦ 30 and Y ≧ X + 1.

  A fourth feature of the present invention includes a step of applying a slurry containing activated carbon, a conductive material and a binder on a current collector to form a first activated carbon electrode layer, and includes activated carbon, a conductive material and a binder. Coating the slurry on the first activated carbon electrode layer to form a second activated carbon electrode layer, and the content ratio of the conductive material contained in the slurry used in the step of forming the second activated carbon electrode layer is: The gist is that it is larger than the content ratio of the conductive material contained in the slurry used in the step of forming the first activated carbon electrode layer.

  A fifth feature of the present invention is that, in the fourth feature described above, the solvent used in the step of forming one of the first activated carbon electrode layer and the second activated carbon electrode layer is the first feature. The gist is that it is different from the solvent used in the step of forming the other electrode layer of the activated carbon electrode layer and the second activated carbon electrode layer.

  A sixth feature of the present invention is that, in the fifth feature described above, the solvent used in the step of forming the one electrode layer is an aqueous solvent, and the solvent used in the step of forming the other electrode layer. Is an organic solvent.

  According to a seventh aspect of the present invention, in the sixth aspect described above, the binder used in the step of forming the one electrode layer is styrene butadiene rubber, and the step of forming the other electrode layer. The gist is that the binder used is polyvinylidene fluoride.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the electrochemical element and electrochemical element which can aim at reduction of internal resistance can be provided, aiming at high capacity | capacitance per unit volume (unit weight). .

  Hereinafter, an electricity storage device according to an embodiment of the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals.

  However, it should be noted that the drawings are schematic and ratios of dimensions are different from actual ones. Therefore, specific dimensions and the like should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

[First Embodiment]
(Configuration of electricity storage device)
Hereinafter, the configuration of the electricity storage device according to the first embodiment will be described with reference to the drawings. FIG. 1 is a diagram illustrating a configuration of an electric double layer capacitor 100 according to the first embodiment.

  As shown in FIG. 1, the electric double layer capacitor 100 includes a positive electrode terminal 10, a current collector 11, an activated carbon electrode 12, a negative electrode terminal 20, a current collector 21, an activated carbon electrode 22, and an electrolytic solution 110. Have

  The positive electrode terminal 10 is an electrode that charges the current collector 11 with a positive charge. The current collector 11 is made of a metal such as an aluminum foil.

  The activated carbon electrode 12 has a multilayer structure constituted by a plurality of layers including activated carbon and a conductive material. The activated carbon electrode 12 is provided on the current collector 11. The activated carbon electrode 12 attracts anions and forms an electric double layer by the positive charges and the anions in the activated carbon electrode 12.

  The negative electrode terminal 20 is an electrode that charges the current collector 21 with negative charges. The current collector 21 is made of a metal such as an aluminum foil.

  The activated carbon electrode 22 has a multilayer structure constituted by a plurality of layers including activated carbon and a conductive material. The activated carbon electrode 22 is provided on the current collector 21. The activated carbon electrode 22 attracts cations, and an electric double layer is formed by the negative charges and the cations in the activated carbon electrode 22.

  The electrolytic solution 110 is an aqueous electrolytic solution or an organic electrolytic solution (for example, propylene carbonate).

(Configuration of electrochemical element)
Below, the structure of the electrochemical element which concerns on 1st Embodiment is demonstrated, referring drawings. FIG. 2 is a diagram showing the configuration of the electrochemical device according to the first embodiment. Here, since the activated carbon electrode 12 and the activated carbon electrode 22 have the same configuration, it should be noted that in FIG. 2, the activated carbon electrode 12 will be described as an example.

  As shown in FIG. 2, the electrochemical device includes a current collector 11 having a thickness a (eg, 300 μm), a first activated carbon electrode layer 12A having a thickness b (eg, 150 μm), and a thickness b (eg, 150 μm). ) Having a second activated carbon electrode layer 12B. The first activated carbon electrode layer 12 </ b> A and the second activated carbon electrode layer 12 </ b> B constitute the activated carbon electrode 12.

  The first activated carbon electrode layer 12A is provided on the current collector 11, and is composed of a conductive material, activated carbon, a binder, and the like. The conductive material is a material having higher conductivity than activated carbon, such as carbon black and metal particles. The binder is a material that binds the conductive material and activated carbon, and is, for example, polyvinylidene fluoride, polytetrafluoroethylene, or the like. Here, the binder used for forming the first activated carbon electrode layer 12A is dissolved or dispersed in an organic solvent (for example, N-methylpyrrolidone) and dissolved or dispersed in an aqueous solvent (for example, water). Material that does not (eg, polyvinylidene fluoride).

  The second activated carbon electrode layer 12B is provided on the first activated carbon electrode layer 12A, and is composed of a conductive material, activated carbon, a binder, and the like. The conductive material is a material having higher conductivity than activated carbon, for example, carbon black. The binder is a material that binds the conductive material and activated carbon. Here, the binder used for forming the second activated carbon electrode layer 12B is dissolved or dispersed in an aqueous solvent (for example, water) and dissolved or dispersed in an organic solvent (for example, N-methylpyrrolidone). (For example, styrene butadiene rubber, polyaniline sulfonic acids, polyacrylic acids, etc.).

  Here, the content ratio Y of the conductive material contained in the second activated carbon electrode layer 12B is larger than the content ratio X of the conductive material contained in the first activated carbon electrode layer 12A. That is, the content ratio of the activated carbon contained in the first activated carbon electrode layer 12A is larger than the content ratio of the activated carbon contained in the second activated carbon electrode layer 12B. Moreover, it is preferable that the content ratio X and the content ratio Y satisfy all the relationships of X ≧ 1, 3 ≦ Y ≦ 30, and Y ≧ X + 1.

(Method for producing electrochemical element)
Below, the manufacturing method of the electrochemical element which concerns on 1st Embodiment is demonstrated, referring drawings. FIG. 3 is a diagram showing a method for manufacturing an electrochemical device according to the first embodiment. Here, since the activated carbon electrode 12 and the activated carbon electrode 22 have the same configuration, it should be noted that in FIG. 3, the activated carbon electrode 12 will be described as an example.

  As shown in FIG. 3, in step 10, a current collector 11 made of a metal such as an aluminum foil is prepared.

  In step 20, the first activated carbon electrode layer 12 </ b> A is formed on the current collector 11. Specifically, a slurry in which a conductive material (for example, carbon black), activated carbon, and a binder (for example, polyvinylidene fluoride) is dissolved in a solvent (for example, an organic solvent) is applied onto the current collector 11. Next, as shown in FIG. 4, the thickness of the slurry applied on the current collector 11 is made uniform (eg, 150 μm) by moving the blade 40 in the A direction. Next, the slurry having a uniform thickness is dried.

  In step 30, the second activated carbon electrode layer 12B is formed on the first activated carbon electrode layer 12A. Specifically, a slurry in which a conductive material (for example, carbon black), activated carbon, and a binder (for example, styrene butadiene rubber) is dissolved in a solvent (for example, an aqueous solvent) is applied onto the first activated carbon electrode layer 12A. Next, as in step 20, the thickness of the slurry applied on the first activated carbon electrode layer 12A is made uniform (eg, 150 μm). Next, the slurry having a uniform thickness is dried.

  Here, the content ratio of the conductive material contained in the slurry used in the formation of the second activated carbon electrode layer 12B (step 30) is the conductive material contained in the slurry used in the formation of the first activated carbon electrode layer 12A (step 20). It is larger than the content ratio. That is, the content ratio of the activated carbon contained in the slurry used in the formation of the first activated carbon electrode layer 12A (step 20) is the content ratio of the activated carbon contained in the slurry used in the formation of the second activated carbon electrode layer 12B (step 30). Bigger than.

  The solvent used in forming the first activated carbon electrode layer 12A (step 20) is different from the solvent used in forming the second activated carbon electrode layer 12B (step 30).

(Function and effect)
According to the activated carbon electrode 12 according to the first embodiment, the content ratio Y of the conductive material contained in the second activated carbon electrode layer 12B is larger than the content ratio X of the conductive material contained in the first activated carbon electrode layer 12A. Even when the thickness of the activated carbon electrode 12 is increased, an increase in electrical resistance of the activated carbon electrode 12 can be suppressed. On the other hand, since the activated carbon electrode 12 has a multilayer structure, the thickness of the activated carbon electrode 12 can be increased and the capacity per unit volume (unit weight) can be increased.

  The binder (eg, polyvinylidene fluoride) contained in the first activated carbon electrode layer 12A is dissolved in a solvent (eg, an aqueous solvent) in which the binder (eg, styrene butadiene rubber) contained in the second activated carbon electrode layer 12B is soluble. It does not melt. That is, when forming the second activated carbon electrode layer 12B on the first activated carbon electrode layer 12A, the solvent used to form the second activated carbon electrode layer 12B does not dissolve the binder contained in the first activated carbon electrode layer 12A. Therefore, deterioration of the first activated carbon electrode layer 12A can be suppressed.

  According to the activated carbon electrode 12 according to the first embodiment, a solvent (for example, an organic solvent) used for forming the first activated carbon electrode layer 12A and a solvent (for example, an aqueous solvent) used for forming the second activated carbon electrode layer 12B. Is different. Therefore, when forming the second activated carbon electrode layer 12B on the first activated carbon electrode layer 12A, the solvent used for forming the second activated carbon electrode layer 12B does not dissolve the binder contained in the first activated carbon electrode layer 12A. Therefore, the activated carbon electrode 12 having a multilayer structure can be easily manufactured.

[Second Embodiment]
The second embodiment will be described below with reference to the drawings. In the following, differences between the first embodiment and the second embodiment described above will be mainly described.

  Specifically, in the first embodiment described above, the activated carbon electrode 12 has a two-layer structure, but in the second embodiment, the activated carbon electrode 12 has a three-layer structure.

(Configuration of electrochemical element)
Below, the structure of the electrochemical element which concerns on 2nd Embodiment is demonstrated, referring drawings. FIG. 5 is a diagram showing a configuration of an electrochemical element according to the second embodiment. In FIG. 5, it should be noted that the same reference numerals are given to the same configurations as those in the first embodiment.

  The activated carbon electrode 12 includes a third activated carbon electrode layer 12C in addition to the first activated carbon electrode layer 12A and the second activated carbon electrode layer 12B. The third activated carbon electrode layer 12C has a thickness d (for example, 150 μm).

  The third activated carbon electrode layer 12C is provided on the second activated carbon electrode layer 12B, and is composed of a conductive material, activated carbon, a binder, and the like. The conductive material is a material having higher conductivity than activated carbon, for example, carbon black. The binder is a material that binds the conductive material and activated carbon. Here, the binder used for forming the first activated carbon electrode layer 12A is a material (for example, polyvinylidene fluoride) that is soluble in an organic solvent but not in an aqueous solvent.

  The content ratio of the conductive material contained in the third activated carbon electrode layer 12C is preferably larger than the content ratio of the conductive material contained in the first activated carbon electrode layer 12A and the second activated carbon electrode layer 12B. Of course, it may be.

  Here, it should be noted that the binder contained in the activated carbon electrode layer has a property of being insoluble in a solvent capable of dissolving the binder contained in another activated carbon electrode layer adjacent thereto. That is, the solvent used for forming the activated carbon electrode layer is different from the solvent used for forming the other activated carbon electrode layer adjacent thereto.

[Third Embodiment]
Hereinafter, a third embodiment will be described with reference to the drawings. In the following, differences between the first embodiment and the third embodiment described above will be mainly described.

  Specifically, in the first embodiment described above, the power storage device is an electric double layer capacitor, but in the third embodiment, the power storage device is a hybrid capacitor.

(Configuration of electricity storage device)
Hereinafter, an electricity storage device according to the third embodiment will be described with reference to the drawings. FIG. 6 is a diagram illustrating a hybrid capacitor 200 according to the third embodiment. In FIG. 6, it should be noted that the same reference numerals are given to the same configurations as those in the first embodiment.

  As shown in FIG. 6, the hybrid capacitor 200 includes a negative electrode terminal 120, a current collector 121, and a battery electrode 122 instead of the negative electrode terminal 20, the current collector 21 and the activated carbon electrode 22.

  The negative electrode terminal 120 is an electrode that charges the current collector 121 with negative charges. The current collector 121 is made of a metal such as an aluminum foil. The battery electrode 122 is an electrode configured to be able to store cations.

  Thus, it should be noted that the present invention is applicable to any power storage device in which an activated carbon electrode is used for either the positive electrode or the negative electrode.

[Example]
Hereinafter, evaluation results of the example and the comparative example will be described with reference to the drawings. In Examples and Comparative Examples, an activated carbon electrode including a first activated carbon electrode layer provided on a current collector and a second activated carbon electrode layer provided on the first activated carbon electrode layer was prepared. Moreover, the capacity of the activated carbon electrode and the inside of the activated carbon electrode are changed by changing the content ratio of the carbon black (conductive material) contained in the first activated carbon electrode layer and the content ratio of the carbon black (conductive material) contained in the second activated carbon electrode layer. Resistance was measured.

  Here, in Examples 1 to 17, it should be noted that the content ratio of carbon black contained in the second activated carbon electrode layer is larger than the content ratio of carbon black contained in the first activated carbon electrode layer. . On the other hand, in Comparative Examples 1 to 24, it should be noted that the content ratio of carbon black contained in the second activated carbon electrode layer is less than or equal to the content ratio of carbon black contained in the first activated carbon electrode layer. .

  FIG. 7 shows the results of measuring the capacitance and internal resistance for each example, and FIG. 8 shows the results of measuring the capacitance and internal resistance for each comparative example.

  Here, the measurement results shown in FIGS. 7 and 8 indicate that the content ratio of the carbon black contained in the first activated carbon electrode layer is the same as the content ratio of the carbon black contained in the second activated carbon electrode layer is “1”. Note that it is normalized.

  In the comprehensive evaluation column, “◯” is indicated when either the capacity or the internal resistance is improved without deteriorating the capacity or the internal resistance. On the other hand, when either one of the capacity or the internal resistance deteriorated, “x” was described.

  In the capacity evaluation column, among the samples whose overall evaluation was “◯”, “○” was described when the improvement in capacity was confirmed. On the other hand, in the internal resistance evaluation column, “◯” is described when an improvement (reduction) in internal resistance is confirmed among samples whose overall evaluation is “◯”.

  As shown in FIG. 7, in the examples (Examples 1 to 17) in which the content ratio of carbon black contained in the second activated carbon electrode layer is larger than the content ratio of carbon black contained in the first activated carbon electrode layer. In all cases, it was confirmed that the overall evaluation was “◯”.

  On the other hand, as shown in FIG. 8, a comparative example in which the content ratio of carbon black contained in the second activated carbon electrode layer is less than or equal to the content ratio of carbon black contained in the first activated carbon electrode layer (Comparative Examples 1 to Comparative Examples). In all of 24), it was confirmed that the overall evaluation was “x”.

  FIG. 9 is a diagram in which the content ratio of carbon black contained in the first activated carbon electrode layer and the second activated carbon electrode layer is plotted for the sample whose comprehensive evaluation is “◯”.

  As shown in FIG. 9, for the comprehensive evaluation, it was confirmed that the content ratio X and the content ratio Y preferably satisfy all the relationships of X ≧ 1, 3 ≦ Y ≦ 30, and Y ≧ X + 1. In the capacity evaluation, it was confirmed that the content ratio X and the content ratio Y preferably satisfy all the relationships of X ≧ 1, Y ≧ 3, Y ≧ X + 1, and Y ≦ −15 / 13X + 615/26. Regarding the internal resistance evaluation, it was confirmed that the content ratio X and the content ratio Y preferably satisfy all the relationships of X ≧ 1, Y ≦ 30, Y ≧ X + 1, and Y> −15 / 13X + 615/26.

[Other Embodiments]
Although the present invention has been described with reference to the above-described embodiments, it should not be understood that the descriptions and drawings constituting a part of this disclosure limit the present invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art.

  For example, in the first embodiment described above, the solvent used for forming the first activated carbon electrode layer 12A is an organic solvent, and the solvent used for forming the second activated carbon electrode layer 12B is an aqueous solvent. It is not limited. Specifically, the solvent used for forming the first activated carbon electrode layer 12A may be an aqueous solvent, and the solvent used for forming the second activated carbon electrode layer 12B may be an organic solvent.

  In the third embodiment described above, the activated carbon electrode is used on the positive electrode side and the battery electrode is used on the negative electrode side. However, the present invention is not limited to this. Specifically, the activated carbon electrode may be used on the negative electrode side, and the battery electrode may be used on the positive electrode side.

It is a figure showing composition of electric double layer capacitor 100 concerning a 1st embodiment. It is a figure which shows the structure of the activated carbon electrode 12 which concerns on 1st Embodiment. It is a figure which shows the manufacturing method of the activated carbon electrode 12 which concerns on 1st Embodiment. It is a figure for demonstrating the manufacturing method of the activated carbon electrode 12 which concerns on 1st Embodiment. It is a figure which shows the structure of the activated carbon electrode 12 which concerns on 2nd Embodiment. It is a figure which shows the structure of the hybrid capacitor 200 which concerns on 3rd Embodiment. It is a figure which shows the evaluation result of a capacity | capacitance and internal resistance about an Example. It is a figure which shows the evaluation result of a capacity | capacitance and internal resistance about a comparative example. It is a figure which shows the optimal combination about the content rate of an electrically-conductive material.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Positive electrode terminal, 11 ... Current collector, 12 ... Activated carbon electrode, 12A ... 1st activated carbon electrode layer, 12B ... 2nd activated carbon electrode layer, 12C ... 3rd activated carbon electrode Layer, 20 ... negative electrode terminal, 21 ... current collector, 22 ... activated carbon electrode, 40 ... blade, 100 ... electric double layer capacitor, 110 ... electrolyte, 120 ... Negative terminal, 121 ... current collector, 122 ... battery electrode, 200 ... hybrid capacitor 200

Claims (7)

An electrochemical device comprising a current collector, a first activated carbon electrode layer provided on the current collector, and a second activated carbon electrode layer provided on the first activated carbon electrode layer,
The first activated carbon electrode layer is composed of activated carbon, a conductive material and a binder,
The second activated carbon electrode layer is composed of activated carbon, a conductive material and a binder,
The conductive material contained in the first activated carbon electrode layer is the same as the conductive material contained in the second activated carbon electrode layer,
The electrochemical element, wherein the content ratio Y of the conductive material contained in the second activated carbon electrode layer is larger than the content ratio X of the conductive material contained in the first activated carbon electrode layer.   The electricity according to claim 1, wherein the property of the binder contained in the first activated carbon electrode layer is soluble in the solvent of the binder contained in the second activated carbon electrode layer. Chemical element. The conductive material included in the first activated carbon electrode layer and the second activated carbon electrode layer is carbon black,
3. The electrochemical device according to claim 1, wherein the content ratio X and the content ratio Y satisfy all the relationships of X ≧ 1, 3 ≦ Y ≦ 30 and Y ≧ X + 1. Applying a slurry containing activated carbon, a conductive material and a binder on a current collector to form a first activated carbon electrode layer;
Applying a slurry containing activated carbon, a conductive material and a binder onto the first activated carbon electrode layer to form a second activated carbon electrode layer;
The content ratio of the conductive material contained in the slurry used in the step of forming the second activated carbon electrode layer is larger than the content ratio of the conductive material contained in the slurry used in the step of forming the first activated carbon electrode layer. The manufacturing method of the electrochemical element characterized by these.   The solvent used in the step of forming one of the first activated carbon electrode layer and the second activated carbon electrode layer is the other electrode layer of the first activated carbon electrode layer and the second activated carbon electrode layer. The method for producing an electrochemical device according to claim 4, wherein the method is different from the solvent used in the step of forming the material. The solvent used in the step of forming the one electrode layer is an aqueous solvent,
The method for producing an electrochemical element according to claim 5, wherein the solvent used in the step of forming the other electrode layer is an organic solvent. The binder used in the step of forming the one electrode layer is styrene butadiene rubber,
The method for producing an electrochemical element according to claim 6, wherein the binder used in the step of forming the other electrode layer is polyvinylidene fluoride.

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