Electrode and Method for Manufacturing the Electrode

Abstract

To provide an electrode of which warpage amount is suppressed while widening a potential window.SOLUTION: An electrode 1 includes: a resin film 2; a metal underlying layer 3; and a conductive carbon layer 4 having a sp2 bonding and a sp3 bonding, which are deposited in one detection in the thickness direction. The ratio of the number of sp3-bonding atoms to the sum of the number of sp3-bonding atoms and the number of sp2-bonding atoms is at least 0.25. The thickness of the metal underlying layer 3 is less than 50 nm.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an electrode.

Background Art

[0002] Conventionally, an electrode in which an underlayer film and a carbon film are sequentially laminated on one side of a plastic substrate is known (see, for example, Patent Document 1 below).

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In recent years, electrodes having even higher sensitivity have been demanded. Therefore, in the carbon film, it has been proposed to increase the ratio of the number of atoms bonded by sp 3 bonding and the number of atoms bonded by sp 2 bonding to widen the potential window. 3 However, if the ratio of the number of atoms bonded by sp

[0005] bonding is increased, the carbon film becomes hard, and thus the electrode has a problem of warping. 3 The present invention provides an electrode in which the potential window can be widened while the amount of warping is suppressed.

[0006]

Means for Solving the Problems

[0007] bonding and sp 2 bonding, and the number of atoms bonded by sp 3 bonding and sp 3 bonding and the number of atoms bonded by sp 2The ratio of the number of sp hybridized atoms to the total number of bonded atoms 3 The electrode includes a metal underlayer having a ratio of the number of bonded atoms of 0.25 or more and a thickness of less than 50 nm.

[0008] The electrode according to the present invention (2) includes the electrode according to (1), wherein the material of the metal underlayer is at least one metal element selected from the group consisting of titanium, tantalum, chromium, molybdenum, and tungsten.

[0009] The electrode according to the present invention (3) includes the electrode according to (1) or (2), wherein the thickness of the conductive carbon layer is 0.2 nm or more and 50 nm or less.

[0010] The electrode according to the present invention (4) includes the electrode according to any one of (1) to (3), wherein the material of the resin film is polyethylene terephthalate.

Advantages of the Invention

[0011] The electrode of the present invention can widen the potential window while suppressing the amount of warpage.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Modes for Carrying Out the Invention

[0013] <One Embodiment> One embodiment of the electrode of the present invention will be described with reference to FIG. 1.

[0014] (Electrode 1) As shown in FIG. 1, the electrode 1 has a predetermined thickness and has a film shape (including a sheet shape) extending in a plane direction orthogonal to the thickness direction. The electrode 1 has a flat surface in the plane direction on one side in the thickness direction and another side spaced apart from the one side in the thickness direction.

[0015] Specifically, the electrode 1 includes a resin film 2, a metal base layer 3 disposed on one surface in the thickness direction of the resin film 2, and a conductive carbon layer 4 disposed on one surface in the thickness direction of the metal base layer 3. That is, the electrode 1 includes the resin film 2, the metal base layer 3, and the conductive carbon layer 4 in this order on one side in the thickness direction. Preferably, the electrode 1 is composed of the resin film 2, the metal base layer 3, and the conductive carbon layer 4. Hereinafter, each layer will be described in detail.

[0016] (Resin film 2) The resin film 2 forms the other surface in the thickness direction of the electrode 1. The resin film 2 has a film shape extending in the plane direction. The resin film 2 is the base film of the electrode 1.

[0017] The resin film 2 has flexibility, for example. Specifically, the folding resistance test (JIS C 5016 (1994)) of the resin film 2 is, for example, 250 times or more, preferably 500 times or more. If the folding resistance test of the resin film 2 is equal to or greater than the above-mentioned lower limit, the resin film 2 has excellent flexibility.

[0018] Examples of the material of the resin film 2 include polyester resins (e.g., polyethylene terephthalate, polyethylene naphthalate), acetate resins, polyethersulfone resins, polycarbonate resins, polyamide resins, polyimide resins, polyolefin resins (e.g., polycyclic olefin polymer), (meth)acrylic resins, polyvinyl chloride resins, polyvinylidene chloride resins, polystyrene resins, polyvinyl alcohol resins, polyarylate resins, polyphenylene sulfide resins, and the like. Preferably, polyester resins are mentioned, and more preferably, polyethylene terephthalate is mentioned.

[0019] The thickness of the resin film 2 is not particularly limited, and is, for example, 2 μm or more, preferably 20 μm or more, and is, for example, 1000 μm or less, preferably 500 μm or less.

[0020] (Metal base layer) The metal underlayer 3 is disposed on one side in the thickness direction of the resin film 2. Specifically, the metal underlayer 3 is in contact with the entire one side in the thickness direction of the resin film 2. The metal underlayer 3 extends in the plane direction. The metal underlayer 3 is an intermediate layer positioned between the resin film 2 and the conductive carbon layer 4.

[0021] Examples of the material of the metal underlayer 3 include group 4 metal elements such as titanium and zirconium, group 5 metal elements such as vanadium, niobium, and tantalum, group 6 metal elements such as chromium, molybdenum, and tungsten, group 7 metal elements such as manganese, group 8 metal elements such as iron, group 9 metal elements such as cobalt, group 10 metal elements such as nickel and platinum, group 11 metal elements such as gold, group 12 metal elements such as zinc, group 13 metal elements such as aluminum and gallium, group 14 metal elements such as germanium and tin, and the like. These materials can be used alone or in combination. Preferred examples of the material of the metal underlayer 3 include titanium, tantalum, chromium, molybdenum, and tungsten. From the viewpoint of chemical stability, more preferred examples include titanium and tungsten, and even more preferred is tungsten.

[0022] The thickness of the metal underlayer 3 is less than 50 nm, preferably 45 nm or less, more preferably 40 nm or less, and even more preferably 35 nm or less. When the thickness of the metal underlayer 3 exceeds the above-mentioned upper limit, the electrode 1 warps.

[0023] Also, the thickness of the metal underlayer 3 is, for example, 0.1 nm or more, preferably 1 nm or more, and more preferably 5 nm or more. When the thickness of the metal underlayer 3 is equal to or more than the above-mentioned lower limit, the sensing stability is excellent.

[0024] The thickness of the metal underlayer 3 is determined by X-ray diffraction method, which will be described in detail in the examples.

[0025] (Conductive carbon layer 4) The conductive carbon layer 4 has conductivity. The conductive carbon layer 4 forms one surface in the thickness direction of the electrode 1. The conductive carbon layer 4 is disposed on one surface in the thickness direction of the metal underlayer 3. Specifically, the conductive carbon layer 4 is in contact with the entire one surface in the thickness direction of the metal underlayer 3. The conductive carbon layer 4 extends in the plane direction.

[0026] The conductive carbon layer 4 has carbon with sp 2 bonds and carbon with sp 3 bonds as the main components. That is, the conductive carbon layer 4 is a layer having a graphite-type structure and a diamond structure. Thereby, the conductive carbon layer 4 has good conductivity and the sensitivity to the measurement object is sufficiently improved.

[0027] The conductive carbon layer 4 can contain oxygen in addition to carbon, for example. Specifically, oxygen is contained, for example, on one surface in the thickness direction of the conductive carbon layer 4. The concentration ratio (O / C) of oxygen to carbon on one surface in the thickness direction of the conductive carbon layer 4 is not particularly limited and is, for example, 0.001 or more and, for example, 0.2 or less.

[0028] Furthermore, a small amount of inevitable impurities other than oxygen can be incorporated into the conductive carbon layer 4.

[0029] In the conductive carbon layer 4, the number of atoms bonded by sp 3 and the ratio of the number of atoms bonded by sp 2 to the sum of the number of atoms bonded by sp 3 (sp 3 / sp 3 +sp 2 ) is 0.25 or more, preferably 0.30 or more, more preferably 0.35 or more. If the ratio of the number of atoms bonded by sp 3 (sp 3 / sp 3 +sp 2 ) is less than the above-mentioned lower limit, the potential window of the electrode 1 cannot be widened.

[0030] Also, sp3 The number of bonded atoms and sp 2 sp with respect to the sum of the number of bonded atoms 3 Ratio of the number of bonded atoms (sp 3 / sp 3 +sp 2 ) is, for example, 0.9 or less, preferably 0.6 or less. sp 3 Ratio of the number of bonded atoms (sp 3 / sp 3 +sp 2 ) is equal to or less than the above-mentioned upper limit, the conductivity of the conductive carbon layer 4 can be ensured, and a decrease in the detection sensitivity of the electrode 1 can be suppressed.

[0031] sp 3 Ratio of the number of bonded atoms (sp 3 / sp 3 +sp 2 ) is calculated based on the peak intensity of the sp 2 bond and the peak intensity of the sp 3 bond in the spectrum obtained by measuring one side in the thickness direction of the conductive carbon layer 4 by X-ray photoelectron spectroscopy.

[0032] The surface resistance on one side in the thickness direction of the conductive carbon layer 4 is, for example, 1.0×10 4 Ω / □ or less, preferably 1.0×10 3 Ω / □ or less.

[0033] The thickness of the conductive carbon layer 4 is, for example, 0.1 nm or more, preferably 0.2 nm or more, and also 100 nm or less, preferably 50 nm or less. If the thickness of the conductive carbon layer 4 is equal to or more than the above-mentioned lower limit, stable electrode characteristics can be exhibited. On the other hand, if the thickness of the conductive carbon layer 4 is equal to or less than the above-mentioned upper limit, excellent flexibility is achieved, and the handleability of the electrode 1 becomes good. The thickness of the conductive carbon layer 4 is determined by X-ray diffraction method. The X-ray diffraction method will be described in detail in the examples.

[0034] (Physical properties of electrode 1) The curl amount of this electrode 1 is small. Specifically, for example, the curl amount of the electrode 1 cut into a rectangular shape of 100 mm × 100 mm is, for example, 40 mm or less, preferably 30 mm or less, more preferably 20 mm or less, still more preferably 15 mm or less, and most preferably 0 mm. As shown in FIG. 2, the curl amount is measured by placing the electrode 1 cut to the above size on the upper surface of the flat plate 5. The temperature at this time is 23°C. Then, when the four corners 6 are warped upward, the amount of warping (height from the flat plate) of each is measured, and the curl amount is obtained as their average. The smaller the curl amount of the electrode 1, the more the warping amount of the electrode 1 is suppressed.

[0035] The thickness of the electrode 1 is the total thickness of the resin film 2, the metal base layer 3, and the conductive carbon layer 4. Specifically, for example, it is 2 μm or more, preferably 20 μm or more, and for example, 1000 μm or less, preferably 500 μm or less.

[0036] (Manufacturing method of electrode 1) Next, the manufacturing method of the electrode 1 will be described.

[0037] First, in this method, a resin film 2 is prepared.

[0038] Next, the metal base layer 3 is formed on one side in the thickness direction of the resin film 2. The method for forming the metal base layer 3 is not particularly limited, and examples include metal film formation methods such as dry methods, for example, wet methods such as plating. Preferably, a dry method is included. Examples of the dry method include PVD method (physical vapor deposition method), CVD method (chemical vapor deposition method), and preferably, the PVD method. Examples of the PVD method include sputtering method, vacuum evaporation method, laser evaporation method, ion plating method (such as arc evaporation method), etc. Preferably, the sputtering method is included. The target in the sputtering method is, for example, the material of the metal base layer 3. Examples of the sputtering gas include inert gases such as Ar and Xe. The pressure in sputtering is, for example, 1 Pa or less. The film formation temperature is, for example, 50°C or more and, for example, 200°C or less.

[0039] Thereafter, the conductive carbon layer 4 is formed on one surface in the thickness direction of the metal base layer 3. Examples of the method for forming the conductive carbon layer 4 include a dry method. Examples of the dry method include a PVD method (physical vapor deposition method) and a CVD method (chemical vapor deposition method), and preferably, the PVD method is mentioned. Examples of the PVD method include a sputtering method, a vacuum evaporation method, a laser evaporation method, an ion plating method (such as an arc evaporation method), etc. Preferably, the sputtering method is mentioned.

[0040] Examples of the sputtering method include an unbalanced magnetron sputtering method (UBM sputtering method), a high-power pulsed sputtering method, an electron cyclotron resonance sputtering method, an RF sputtering method, a DC sputtering method (such as a DC magnetron sputtering method), a DC pulsed sputtering method, an ion beam sputtering method, etc. 3 From the viewpoint of being able to easily set the ratio of the number of bonded atoms within the above-described desired range, and also from the viewpoint of being able to improve the film formation rate and the adhesion to the metal base layer 3, more preferably, the UBM sputtering method is mentioned.

[0041] Examples of the target in the sputtering method include sintered carbon. Examples of the sputtering gas include an inert gas. The pressure in sputtering is, for example, 1 Pa or less. The film formation temperature is, for example, 0°C or higher and, for example, 100°C or lower.

[0042] In addition, the conductive carbon layer 4 can be subjected to known surface treatments such as ion milling, ion impact treatment (ion bombardment), electrolytic polishing, and voltage application cycles (number of cycles: 2 or more and 20 or less) as necessary.

[0043] sp 3 In order to set the ratio of the number of bonded atoms within the above-described desired range, the above-described sputtering conditions and surface treatments are appropriately selected.

[0044] As a result, an electrode 1 is obtained that includes a resin film 2, a metal base layer 3, and a conductive carbon layer 4 in this order on one side in the thickness direction.

[0045] (Use of electrode 1) The electrode 1 can be used as various electrodes. Preferably, it is an electrode for electrochemical measurement for performing an electrochemical measurement method. Specifically, it can be used as a working electrode for performing cyclic voltammetry (CV) or a working electrode for performing anodic stripping voltammetry (ASV).

[0046] (Function and effect of one embodiment) And according to this electrode 1, since the ratio of the number of atoms bonded by sp 3 and the number of atoms bonded by sp 2 to the number of atoms bonded by sp 3 is 0.25 or more, the potential window can be widened.

[0047] On the other hand, in this electrode 1, since the thickness of the metal base layer 3 is less than 50 nm, the internal stress that applies a force to distort the resin film 2 in the metal base layer 3 is reduced. As a result, the amount of warpage is suppressed.

[0048] Therefore, this electrode 1 can widen the potential window while suppressing the amount of warpage.

[0049] Also, in this electrode 1, if the material of the metal base layer 3 is at least one metal element selected from the group consisting of titanium, tantalum, chromium, molybdenum, and tungsten, sufficient adhesion between the resin film 2 and the conductive carbon layer 4 can be ensured.

[0050] Moreover, if the thickness of the conductive carbon layer 4 is 0.2 nm or more, stable electrode characteristics can be exhibited. On the other hand, if the thickness of the conductive carbon layer 4 is 50 nm or less, it is excellent in flexibility, so the handleability of the electrode 1 is good.

[0051] (Modification example) As shown in FIG. 1, in one embodiment, the electrode 1 includes one resin film 2, one metal base layer 3, and one conductive carbon layer 4. On the other hand, it can also include one resin film 2, two metal base layers 3, and two conductive carbon layers 4. That is, the electrode 1 can include two metal base layers 3 and two conductive carbon layers 4 with respect to one resin film 2. In this case, the conductive carbon layer 4, the metal base layer 3, the resin film 2, the metal base layer 3, and the conductive carbon layer 4 are arranged in order in the thickness direction.

[0052] Also, in order to form the metal base layer 3 with a desired thickness, the above-described metal film formation method can be performed multiple times.

Examples

[0053] Examples and comparative examples are shown below to explain the present invention more specifically. Note that the present invention is not limited to any examples and comparative examples. Also, specific numerical values such as the blending ratio (content ratio), physical property values, parameters, etc. used in the following description can be replaced with the upper limit values (numerical values defined as "below" and "less than") or lower limit values (numerical values defined as "above" and "exceeding") of the corresponding blending ratio (content ratio), physical property values, parameters, etc. described in the above "Mode for Carrying Out the Invention".

[0054] (Method for Measuring the Thickness of the Metal Base Layer 3 and the Thickness of the Conductive Carbon Layer 4) First, the method for measuring the thickness of the metal base layer 3 and the thickness of the conductive carbon layer 4 is shown below. Specifically, based on the X-ray reflectivity method as the measurement principle, using a powder X-ray diffractometer (manufactured by Rigaku Corporation, "RINT-2200"), the X-ray reflectivity is measured under the following <measurement conditions>, and the obtained measurement data is analyzed by analysis software (manufactured by Rigaku Corporation, "GXRR3") to calculate the thickness of the metal base layer 3 and the thickness of the conductive carbon layer 4 for each example and each comparative example.

[0055] Regarding the analysis, a three-layer model of the resin film 2, the metal base layer 3, and the conductive carbon layer 4 was adopted under the following <Analysis Conditions>, and the target thickness and density of 19.30 g / cm of the metal base layer 3 3 were input as initial values, and also the target thickness and density of 19.5 g / cm of the conductive carbon layer 4 3 were input as initial values. Then, by performing the least squares fitting with the measured values, the thicknesses of the metal base layer 3 and the conductive carbon layer 4 were calculated respectively.

[0056] <Measurement Conditions> Measuring device: Powder X-ray diffractometer (manufactured by Rigaku Corporation, "RINT-2000") Light source: Cu-Kα ray (wavelength: 1,5418 Å), 40 kV, 40 mA Optical system: Parallel beam optical system Divergence slit: 0.05 mm Receiving slit: 0.05 mm Monochromatization and parallelization: Using a multilayer Gobel mirror Measurement mode: θ / 2θ scan mode Measurement range (2θ): 0.3 to 2.0°

[0057] <Analysis Conditions> Analysis software: Manufactured by Rigaku Corporation, "GXRR3" Analysis method: Least squares fitting Analysis range (2θ): 2θ = 0.3 to 2.0°

[0058] (Example 1) (Preparation of Resin Film 2) A resin film 2 made of polyethylene terephthalate with a thickness of 50 μm was prepared.

[0059] (Formation of Metal Base Layer 3) Next, a metal base layer 3 made of tungsten was formed on one side in the thickness direction of the resin film 2 by sputtering. The thickness of the metal base layer 3 was 40 nm. The conditions of the sputtering method are described below.

[0060] Target material: Tungsten Argon gas pressure: 0.6 Pa Target power: 400 W Film-forming roll temperature: 120 °C

[0061] (Formation of the conductive carbon layer 4) Thereafter, by the UBM sputtering method, the conductive carbon layer 4 was formed on one surface in the thickness direction of the metal underlayer 3. The thickness of the conductive carbon layer 4 was 30 nm. The conditions of the UBM sputtering method are described below.

[0062] Target material: Sintered carbon Argon gas pressure: 0.8 Pa Target power: 400 W Film-forming roll temperature: 30 °C DC bias (between the metal underlayer 3 and the target material): 75 V

[0063] Thereafter, a voltage application cycle in which the applied voltage was reciprocated between 0 V and 2.3 V was performed 10 times on the conductive carbon layer 4.

[0064] Thereby, the electrode 1 was obtained.

[0065] (Example 2) The same treatment as in Example 1 was performed to obtain the electrode 1. However, the thickness of the metal underlayer 3 was changed from 40 nm to 30 nm.

[0066] (Example 3) The same treatment as in Example 1 was performed to obtain the electrode 1. However, the thickness of the metal underlayer 3 was changed from 40 nm to 10 nm.

[0067] (Example 4) The same treatment as in Example 1 was performed to obtain the electrode 1. However, the thickness of the metal underlayer 3 was changed from 40 nm to 30 nm. Also, the DC bias was changed from 75 V to 30 V.

[0068] (Comparative Example 1) The same treatment as in Example 1 was performed to obtain the electrode 1. However, the thickness of the metal underlayer 3 was changed from 40 nm to 50 nm.

[0069] (Comparative Example 2) The same process as in Example 1 was performed to obtain Electrode 1. However, the thickness of the metal underlayer 3 was changed from 40 nm to 50 nm. On the other hand, no DC bias was applied and no voltage application cycle was performed.

[0070] (Example 5) The same process as in Example 2 was performed to obtain Electrode 1. However, in the formation of the metal underlayer 3, chromium was used as the target material. That is, the material of the metal underlayer 3 was changed from tungsten to chromium.

[0071] (Comparative Example 3) The same process as in Example 5 was performed to obtain Electrode 1. However, the thickness of the metal underlayer 3 was changed from 30 nm to 50 nm.

[0072] (Example 6) The same process as in Example 2 was performed to obtain Electrode 1. However, in the formation of the metal underlayer 3, molybdenum was used as the target material. That is, the material of the metal underlayer 3 was changed from tungsten to molybdenum.

[0073] (Comparative Example 4) The same process as in Example 6 was performed to obtain Electrode 1. However, the thickness of the metal underlayer 3 was changed from 30 nm to 50 nm.

[0074] (Example 7) The same process as in Example 2 was performed to obtain Electrode 1. However, in the formation of the metal underlayer 3, tantalum was used as the target material. That is, the material of the metal underlayer 3 was changed from tungsten to tantalum.

[0075] (Comparative Example 5) The same process as in Example 7 was performed to obtain Electrode 1. However, the thickness of the metal underlayer 3 was changed from 30 nm to 50 nm.

[0076] (Example 8) The same process as in Example 2 was performed to obtain Electrode 1. However, in the formation of the metal underlayer 3, titanium was used as the target material. That is, the material of the metal underlayer 3 was changed from tungsten to titanium.

[0077] The materials of the metal underlayer 3, the thickness of the metal underlayer 3, and the thickness of the conductive carbon layer 4 in Examples 1 to 8 and Comparative Examples 1 to 5 are shown in Tables 1 and 2.

[0078] (Evaluation) The following items were evaluated. The results are described in Tables 1 and 2.

[0079] (sp 3 The number of bonded atoms and sp 2 Ratio of sp to the sum of the number of bonded atoms 3 (Ratio of the number of bonded atoms) X-ray photoelectron spectroscopy was performed under the following <Measurement Conditions> on one side in the thickness direction of the conductive carbon layer 4. In the spectrum obtained thereby, based on the peak intensity of the sp 2 bond and the peak intensity of the sp 3 bond, the number of carbon atoms bonded by sp 2 and the number of carbon atoms bonded by sp 3 ratio of the number of carbon atoms bonded by sp to the sum of the number of carbon atoms bonded by sp 3 (sp 3 / sp 3 +sp 2 ) was calculated.

[0080] <Measurement Conditions> Measuring device: X-ray photoelectron spectroscopy (XPS) device (manufactured by Shimadzu Corporation, trade name "AXIS Nova") X-ray source: AlKα (1486.6 eV) with a Rowland circle diameter of 500 mm monochromator, 15 kV, 10 mA Photoelectron spectrometer: Orbit radius 165 mm, electrostatic double hemispherical analyzer / spherical mirror analyzer composite type Detector: Delay line detector (DLD) system Energy resolution: Ag3d5 / 2 photoelectron peak has a full width at half maximum of 0.48 eV or less Charge neutralization: Uniform low-energy electron irradiation

[0081] (Amount of curl) First, electrode 1 was cut into a size of 100 mm in length and 100 mm in width. Next, as shown in Fig. 2, electrode 1 was placed on the upper surface of flat plate 5 with resin film 2 on the lower side. The temperature at this time was 23°C. After 1 minute had passed, the four corners 6 had curled up, and the amount of curl (height from flat plate 5) for each was measured, and the amount of curl was obtained as the average of these values. Based on the following criteria, suppression of the amount of warp was evaluated from the amount of curl.

[0082] ○: The amount of curl was 40 mm or less. ×: The amount of curl exceeded 40 mm.

[0083] [Table 1]

[0084] [Table 2]

[0085] Note that the above invention was provided as an exemplary embodiment of the present invention, but this is merely an example and should not be construed in a limiting manner. Modifications of the present invention that are obvious to those skilled in the art are included in the scope of the claims described below.

Industrial Applicability

[0086] The electrode is used for an electrode for electrochemical measurement for carrying out an electrochemical measurement method.

Explanation of Reference Numerals

[0087] 1 Electrode 2 Resin film 3 Metal underlayer 4 Conductive carbon layer

Claims

1. A resin film; A metal underlayer; s.p. ２ Bonds and sp ３ A conductive carbon layer having a bond are provided in order toward one side in the thickness direction, s.p. ３ Number of atoms bonded and sp ２ sp relative to the sum of the number of bonded atoms ３ The ratio of the number of bonded atoms is 0.3 or more and 0.4 or less, The electrode, wherein the resin film has a thickness of 2 μm or more and 1000 μm or less.

2. The electrode described in claim 1, wherein the thickness of the metal underlayer is 30 nm or more and 40 nm or less.

3. The electrode described in claim 1, wherein the material of the metal underlayer is at least one metal element selected from the group consisting of zirconium, vanadium, niobium, tantalum, molybdenum, manganese, iron, cobalt, nickel, platinum, gold, zinc, gallium, germanium and tin.

4. The electrode of claim 1, wherein the conductive carbon layer comprises carbon and oxygen.

5. The electrode according to claim 1 , wherein the conductive carbon layer has a thickness of 0.2 nm or more and 50 nm or less.

6. The electrode described in claim 2, wherein the thickness of the conductive carbon layer is 0.2 nm or more and 50 nm or less.

7. The electrode described in claim 3, wherein the thickness of the conductive carbon layer is 0.2 nm or more and 50 nm or less.

8. The electrode of claim 4, wherein the conductive carbon layer has a thickness of 0.2 nm or more and 50 nm or less.

9. The electrode according to any one of claims 1 to 8, wherein the material of the resin film is polyethylene terephthalate.

10. A step of preparing a resin film; forming a metal underlayer on one surface in a thickness direction of the resin film; forming a conductive carbon layer having sp 2 bonds and sp 3 bonds on one surface in a thickness direction of the metal underlayer; the ratio of the number of sp 3 bonded atoms to the sum of the number of sp 3 bonded atoms and the number of sp 2 bonded atoms is 0.3 or more and 0.4 or less; The method for producing an electrode, wherein the resin film has a thickness of 2 μm or more and 1000 μm or less.

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