Electrode, electrochemical sensor, biosensor, and method for manufacturing electrode

Abstract

An electrode comprises, in order toward one thickness-direction side, a base material film and an electrochemically active layer that has electrochemical activity. The electrochemically active layer contains an alloy including nickel. At least part of one thickness-direction surface of the electrochemically active layer is exposed.

Description

Electrodes, electrochemical sensors, biosensors, and methods for manufacturing electrodes

[0001] This invention relates to electrodes, electrochemical sensors, biosensors, and methods for manufacturing electrodes.

[0002] Traditionally, carbon electrodes have been used as sensor electrodes.

[0003] As such an electrode, for example, an electrode has been proposed that comprises a substrate, a niobium layer, and a conductive carbon layer arranged sequentially toward one side in the thickness direction (see, for example, Patent Document 1 below).

[0004] International Publication 2024 / 111455 Brochure

[0005] On the other hand, improved productivity is required for electrodes.

[0006] The present invention provides an electrode with excellent productivity, an electrochemical sensor equipped with the electrode, a biosensor equipped with the electrode, and a method for manufacturing the electrode.

[0007] The present invention [1] is an electrode comprising a base film and an electrochemically active layer having electrochemical activity, arranged sequentially toward one side in the thickness direction, wherein the electrochemically active layer contains a nickel-containing alloy, and at least a portion of one side in the thickness direction of the electrochemically active layer is exposed.

[0008] The present invention [2] includes the electrode described in [1] above, wherein the electrochemically active layer comprises an alloy of nickel and chromium, and the nickel content is 70% by mass or more and 97% by mass or less relative to the alloy.

[0009] The present invention [3] includes the electrode described in [1] or [2] above, further comprising a metal underlayer between the base film and the electrochemically active layer.

[0010] The present invention [4] includes an electrochemical sensor comprising the electrode described in any one of the above items [1] to [3].

[0011] The present invention [5] includes a biosensor comprising the electrode described in any one of the above [1] to [3].

[0012] The present invention [6] is a method for manufacturing an electrode, comprising a preparation step of preparing a base film and an electrochemically active layer placement step of placing an electrochemically active layer having electrochemical activity on one side in the thickness direction of the base film, wherein the electrochemically active layer placement step is carried out by a roll-to-roll method, and the electrochemically active layer contains an alloy containing nickel.

[0013] In the electrode of the present invention, the electrochemically active layer is electrochemically active. Therefore, when this electrode is used as a sensor, the sensor response can be improved. Furthermore, the electrochemically active layer contains an alloy containing nickel. Therefore, the deposition rate of the electrochemically active layer can be increased. As a result, productivity can be improved.

[0014] The electrochemical sensor of the present invention is equipped with the electrode of the present invention. Therefore, productivity can be improved.

[0015] The biosensor of the present invention is equipped with the electrode of the present invention. Therefore, productivity can be improved.

[0016] In the electrode manufacturing method of the present invention, the electrochemically active layer has electrochemical activity. Therefore, when this electrode is used as a sensor, the sensor response can be improved. Furthermore, the electrochemically active layer contains an alloy containing nickel. Therefore, the deposition rate of the electrochemically active layer can be increased. As a result, productivity can be improved.

[0017] Figure 1 is a schematic cross-sectional view of one embodiment of the electrode of the present invention. Figures 2A to 2C show one embodiment of the method for manufacturing the electrode of the present invention. Figure 2A shows a preparation step for preparing a base film. Figure 2B shows a metal underlayment placement step in which a metal underlayment is placed on one side of the base film in the thickness direction. Figure 2C shows an electrochemically active layer placement step in which an electrochemically active layer is placed on one side of the metal underlayment in the thickness direction.

[0018] An embodiment of the electrode of the present invention will be described with reference to Figure 1.

[0019] In Figure 1, the vertical direction of the paper is the vertical direction (thickness direction). The upper side of the paper is the upper side (one side in the thickness direction). The lower side of the paper is the lower side (the other side in the thickness direction). The horizontal direction and depth direction of the paper are plane directions perpendicular to the vertical direction. Specifically, these correspond to the directional arrows in each figure.

[0020] <Electrode> As shown in Figure 1, the electrode 1 has a film shape (including a sheet shape) with a predetermined thickness. The electrode 1 extends in a planar direction perpendicular to the thickness direction. The electrode 1 has a flat upper surface and a flat lower surface.

[0021] The electrode 1 comprises a base film 2, a metal underlayer 3, and an electrochemically active layer 4, arranged sequentially toward one side in the thickness direction. Specifically, the electrode 1 comprises a base film 2, a metal underlayer 3 directly disposed on the upper surface (one side in the thickness direction) of the base film 2, and an electrochemically active layer 4 directly disposed on the upper surface (one side in the thickness direction) of the metal underlayer 3. Preferably, the electrode 1 consists of a base film 2, a metal underlayer 3, and an electrochemically active layer 4.

[0022] From the viewpoint of ease of handling, the thickness of electrode 1 is, for example, 10 μm to 1000 μm, preferably 25 μm to 500 μm, more preferably 50 μm to 250 μm, even more preferably 100 μm to 225 μm, and most preferably 150 μm to 200 μm.

[0023] <Base Film> The base film 2 has a film shape. The base film 2 is the bottom layer of the electrode 1.

[0024] Examples of materials for the base film 2 include resin, ceramics, and metal. From the viewpoint of flexibility, resin is preferred as the material for the base film 2. In other words, the base film 2 is preferably a resin film.

[0025] Examples of resins include polyester resins, (meth)acrylic resins, olefin resins, polycarbonate resins, polyethersulfone resins, polyarylate resins, melamine resins, polyamide resins, polyimide resins, cellulose resins, and polystyrene resins. Examples of polyester resins include polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate. Examples of (meth)acrylic resins include polymethyl methacrylate. Examples of olefin resins include polyethylene, polypropylene, and cycloolefin polymers. Examples of cellulose resins include triacetylcellulose.

[0026] Preferably, the resin is a polyester resin. More preferably, the resin is polyethylene terephthalate.

[0027] The resins can be used individually or in combination of two or more types.

[0028] The thickness of the base film 2 is obtained by subtracting the thickness of the metal underlayer 3 (nm) and the thickness of the electrochemically active layer 4 (nm) from the thickness of the electrode 1 (μm) described above, and is, for example, 10 μm to 1000 μm, preferably 25 μm to 500 μm, more preferably 50 μm to 250 μm, even more preferably 100 μm to 225 μm, and particularly preferably 150 μm to 200 μm.

[0029] The thickness of the base film 2 can be measured using a dial gauge (PEACOCK, "DG-205").

[0030] <Metal underlayment> The metal underlayment 3 assists in the conductivity of the electrochemically active layer 4.

[0031] The metal underlayer 3 is positioned over the entire upper surface of the base film 2 so as to be in contact with the upper surface of the base film 2. The metal underlayer 3 is positioned between the base film 2 and the electrochemically active layer 4.

[0032] The material of the metal underlayer 3 is a metal. The metal is a metal other than an alloy containing nickel, and examples thereof include titanium, tantalum, chromium, molybdenum, tungsten, silver, copper, niobium, and alloys thereof. From the viewpoint of electrochemical activity, niobium is preferably used as the material of the metal underlayer 3. In other words, the metal underlayer 3 is preferably a niobium layer.

[0033] The material of the metal underlayer 3 can be used alone or in combination of two or more.

[0034] Although it will be described in detail later, the metal underlayer 3 is preferably formed by a sputtering method. That is, the metal underlayer 3 is preferably a sputtering layer.

[0035] The thickness of the metal underlayer 3 is, for example, 1 nm to 200 nm, preferably 2 nm to 150 nm, more preferably 3 nm to 100 nm, still more preferably 4 nm to 80 nm, particularly preferably 5 nm to 50 nm, further 6 nm to 45 nm, further 7 nm to 40 nm, further 8 nm to 36 nm, further 9 nm to 33 nm, and further 10 nm to 30 nm.

[0036] Specifically, from the viewpoint of reducing the surface resistance of the electrode 1, the thickness of the metal underlayer 3 is, for example, 1 nm or more, preferably 2 nm or more, more preferably 3 nm or more, still more preferably 4 nm or more, particularly preferably 5 nm or more, further 6 nm or more, further 7 nm or more, further 8 nm or more, further 9 nm or more, and further 10 nm or more. From the viewpoints of improving adhesion and suppressing crack generation, the thickness is, for example, 200 nm or less, preferably 150 nm or less, more preferably 100 nm or less, still more preferably 80 nm or less, particularly preferably 50 nm or less, further 45 nm or less, further 40 nm or less, further 36 nm or less, further 33 nm or less, and further 30 nm or less.

[0037] <Electrochemical Active Layer> The electrochemical active layer 4 has a film shape. The electrochemical active layer 4 is disposed on the entire upper surface of the metal underlayer 3 so as to be in contact with the upper surface of the metal underlayer 3. The electrochemical active layer 4 is the uppermost layer of the electrode 1. All of one side in the thickness direction of the electrochemical active layer 4 is exposed.

[0038] The electrochemical active layer 4 has electrochemical activity. Specifically, the redox potential difference ΔEp measured by cyclic voltammetry (CV), which will be described in detail in the examples below, of the electrochemical active layer 4 is, for example, 0.70 or less, preferably 0.30 or less, and also, for example, 0.01 or more, preferably 0.08 or more.

[0039] The electrochemical active layer contains an alloy containing nickel. The electrochemical active layer is formed from an alloy containing nickel.

[0040] The alloy preferably contains nickel and another metal other than nickel.

[0041] In such a case, nickel is the main component in the alloy. In other words, the content ratio of nickel is, for example, 50% by mass or more with respect to the alloy.

[0042] Specifically, the content ratio of nickel is, for example, 70% to 97% by mass, preferably 75% to 96% by mass, more preferably 80% to 95% by mass, and still more preferably 85% to 94% by mass with respect to the alloy.

[0043] More specifically, the content ratio of nickel is, from the viewpoint of electrochemical activity, for example, 70% by mass or more, preferably 75% by mass or more, more preferably 80% by mass or more, and still more preferably 85% by mass or more with respect to the alloy, and also, from the viewpoint of electrochemical activity, for example, 97% by mass or less, preferably 96% by mass or less, more preferably 95% by mass or less, and still more preferably 94% by mass or less.

[0044] Other metals include, for example, gold, platinum, silver, chromium, niobium, titanium, vanadium, tungsten, molybdenum, zirconium, iron, tin, and lead. Chromium is a preferred other metal. In other words, the alloy preferably contains nickel and chromium. More preferably, the alloy consists of nickel and chromium.

[0045] Other metals can be used individually or in combination of two or more.

[0046] The content of other metals is, for example, 3% to 30% by mass, preferably 4% to 25% by mass, more preferably 5% to 20% by mass, and even more preferably 6% to 15% by mass, relative to the alloy.

[0047] More specifically, the content of other metals relative to the alloy is, from the viewpoint of electrochemical activity, for example, 3% by mass or more, preferably 4% by mass or more, more preferably 5% by mass or more, and even more preferably 6% by mass or more. Also, from the viewpoint of electrochemical activity, for example, 30% by mass or less, preferably 25% by mass or less, more preferably 20% by mass or less, and even more preferably 15% by mass or less.

[0048] Furthermore, in particular, when the alloy consists of nickel and chromium, the nickel content is, for example, 70% to 97% by mass, preferably 75% to 96% by mass, more preferably 80% to 95% by mass, and even more preferably 85% to 94% by mass, relative to the alloy.

[0049] More specifically, the nickel content relative to the alloy is, from the viewpoint of electrochemical activity, for example, 70% by mass or more, preferably 75% by mass or more, more preferably 80% by mass or more, and even more preferably 85% by mass or more. Also, from the viewpoint of electrochemical activity, for example, 97% by mass or less, preferably 96% by mass or less, more preferably 95% by mass or less, and even more preferably 94% by mass or less.

[0050] The chromium content is, for example, 3% to 30% by mass relative to the alloy, preferably 4% to 25% by mass, more preferably 5% to 20% by mass, and even more preferably 6% to 15% by mass.

[0051] More specifically, the chromium content relative to the alloy is, from the viewpoint of electrochemical activity, for example, 3% by mass or more, preferably 4% by mass or more, more preferably 5% by mass or more, and even more preferably 6% by mass or more. Also, from the viewpoint of electrochemical activity, for example, 30% by mass or less, preferably 25% by mass or less, more preferably 20% by mass or less, and even more preferably 15% by mass or less.

[0052] The electrochemically active layer 4 is formed by a sputtering method, as will be described in more detail later. In other words, the electrochemically active layer 4 is preferably a sputtering layer.

[0053] The thickness of the electrochemically active layer 4 is, for example, 1 nm to 70 nm, preferably 2 nm to 40 nm, more preferably 3 nm to 20 nm, and even more preferably 3 nm to 10 nm.

[0054] More specifically, the thickness of the electrochemically active layer 4 is, from the viewpoint of electrochemical activity, for example, 1 nm or more, preferably 2 nm or more, and more preferably 3 nm or more. From the viewpoint of productivity, it is, for example, 70 nm or less, preferably 40 nm or less, more preferably 20 nm or less, and even more preferably 10 nm or less.

[0055] <Method for Manufacturing Electrodes> An embodiment of the method for manufacturing electrode 1 will be described with reference to Figures 2A to 2C.

[0056] The method for manufacturing the electrode 1 comprises a preparation step of preparing a base film 2, a metal base layer placement step of placing a metal base layer 3 on one side of the base film 2 in the thickness direction, and an electrochemically active layer placement step of placing an electrochemically active layer 4 on one side of the metal base layer 3 in the thickness direction. Furthermore, this method is preferably carried out using a roll-to-roll method. Specifically, the metal base layer placement step and the electrochemically active layer placement step are carried out using a roll-to-roll method. In such cases, the transport speed is, for example, 0.1 m / min to 20.0 m / min, preferably 0.5 m / min to 10.0 m / min, and more preferably 1.0 m / min to 3.0 m / min.

[0057] [Preparation Step] In the preparation step, the base film 2 is prepared as shown in Figure 2A.

[0058] [Metal Substrate Placement Process] In the metal substrate placement process, as shown in Figure 2B, the metal substrate 3 is placed on one side in the thickness direction of the base film 2.

[0059] Examples of methods for forming the metal underlayment 3 include a dry method and a wet method. Preferably, the dry method is used for forming the metal underlayment 3.

[0060] Examples of dry methods include PVD (Physical Vapor Deposition) and CVD (Chemical Vapor Deposition). PVD is preferred as a dry method. Examples of PVD methods include sputtering (e.g., magnetron sputtering (magnetron DC discharge or magnetron DC pulsed discharge)), vacuum deposition, laser deposition, and ion plating. Sputtering is preferred as the PVD method.

[0061] In the sputtering method, a target (material for the metal underlayment 3) and a base film 2 are placed facing each other in a vacuum chamber. Then, by supplying sputtering gas and applying voltage from a power source, gas ions are accelerated and irradiated onto the target, ejecting the target material from the target surface. This target material is then deposited onto the surface (one side in the thickness direction) of the base film 2 to form the metal underlayment 3.

[0062] Examples of sputtering gases include inert gases (such as argon gas).

[0063] The film deposition pressure is, for example, 0.05 Pa to 1.00 Pa, preferably 0.10 Pa to 0.50 Pa, and more preferably 0.15 Pa to 0.30 Pa.

[0064] The power supply may be, for example, a DC power supply, an AC power supply, an MF power supply, or an RF power supply. A combination of these may also be used.

[0065] The discharge power is, for example, 1.0 W / cm². ２ ~40.0 W / cm ２ Preferably, 2.0 W / cm² ２~20.0 W / cm ２ , comfortably, 2.5 W / cm ２ ~10.0 W / cm ２ More preferably, 3.0 W / cm² ２ ~5.0 W / cm ２ That is the case.

[0066] The temperature of the base film 2 (film formation temperature) is, for example, -10°C to 200°C, preferably 20°C to 100°C, and more preferably 30°C to 60°C.

[0067] This places the metal underlayer 3 on one side of the base film 2 in the thickness direction.

[0068] [Electrochemically Active Layer Placement Process] In the electrochemically active layer placement process, as shown in Figure 2C, the electrochemically active layer 4 is placed on one side in the thickness direction of the metal substrate layer 3. In other words, in the electrochemically active layer placement process, the electrochemically active layer 4 is placed on one side in the thickness direction of the base film 2.

[0069] Methods for forming the electrochemically active layer 4 include, for example, sputtering (e.g., magnetron sputtering (magnetron DC discharge or magnetron DC pulsed discharge)).

[0070] In the sputtering method, the material of the electrochemically active layer 4 (a nickel-containing alloy) is selected as the target.

[0071] Examples of sputtering gases include inert gases (such as argon gas).

[0072] The film deposition pressure is, for example, 0.05 Pa to 1.00 Pa, preferably 0.10 Pa to 0.50 Pa, and more preferably 0.15 Pa to 0.30 Pa.

[0073] The power supply may be, for example, a DC power supply, an AC power supply, an MF power supply, or an RF power supply. A combination of these may also be used.

[0074] The discharge power is appropriately adjusted according to the thickness of the electrochemical active layer 4. Further, since the electrochemical active layer 4 is formed from an alloy containing nickel, the discharge power can be lowered, and as a result, the film formation rate (described later) can be increased. The discharge power is, for example, 0.5 W / cm ２ to 30.0 W / cm ２ and preferably 1.0 W / cm ２ to 22.0 W / cm ２ .

[0075] The temperature of the base film 2 (film formation temperature) is, for example, -10°C to 200°C, preferably 20°C to 100°C, more preferably 30°C to 60°C.

[0076] Thereby, the electrochemical active layer 4 is disposed on one side in the thickness direction of the metal underlayer 3. Thus, the electrode 1 is manufactured.

[0077] In the electrode 1, the electrochemical active layer 4 has electrochemical activity. Therefore, when this electrode 1 is used as a sensor, the sensor responsiveness can be improved. Further, the electrochemical active layer 4 contains an alloy containing nickel. Therefore, the film formation rate (described later) of the electrochemical active layer 4 can be increased. As a result, productivity can be improved.

[0078] Such an electrode 1 can be preferably used particularly as an electrode of an electrochemical sensor. That is, the electrode 1 is preferably an electrochemical sensor electrode.

[0079] An electrochemical sensor is a sensor that converts into an electrical signal using the redox potential. Examples of the electrochemical sensor include an actuator, a humidity sensor, a gas concentration sensor, an ion concentration sensor, an odor sensor, and a biosensor. As the electrochemical sensor, preferably, a biosensor is mentioned.

[0080] 2. Biosensor In the following description, as an example of the biosensor, a blood glucose sensor will be described in detail. In the blood glucose sensor, the analyte is, for example, a ferrocyanide compound. In the following description, the case where the analyte is a ferrocyanide compound will be described in detail.

[0081] The blood glucose sensor comprises an electrode 1 and a reagent layer arranged sequentially in one direction in the thickness direction. More specifically, in the blood glucose sensor, the reagent layer is arranged on at least a portion of one side in the thickness direction of the electrochemically active layer 4 of the electrode 1.

[0082] The reagent layer contains an enzyme and a ferricyanine compound or a ferrocyanine compound.

[0083] An example of an enzyme is glucose oxidase.

[0084] Examples of ferricyanide compounds include potassium ferricyanide and sodium ferricyanide. Potassium ferricyanide is preferred as the ferricyanide compound.

[0085] Examples of ferrocyanide compounds include potassium ferrocyanide and sodium ferrocyanide.

[0086] The following describes in detail a method for detecting glucose in the blood using a blood glucose sensor, specifically focusing on the case where the reagent layer contains an enzyme and potassium ferricyanide.

[0087] In this method, blood is first added to one side of the reagent layer in the thickness direction. At this time, the glucose in the blood is oxidized by the enzyme in the reagent layer. The enzyme then reduces potassium ferricyanide to potassium ferrocyanide.

[0088] Next, a voltage is applied to the blood glucose sensor. This causes potassium ferrocyanide to oxidize to potassium ferricyanide.

[0089] By measuring the current flowing during the above oxidation reaction, glucose in the blood can be indirectly detected.

[0090] The blood glucose sensor is equipped with an electrode 1. Therefore, it offers excellent sensor responsiveness and productivity.

[0091] 3. Effects: In the electrode 1, the electrochemically active layer 4 has electrochemical activity. Therefore, when this electrode 1 is used as a sensor, the sensor responsiveness can be improved. Furthermore, the electrochemically active layer 4 contains an alloy containing nickel. Therefore, the film deposition rate of the electrochemically active layer 4 can be increased. As a result, productivity can be improved.

[0092] More specifically, when forming the electrochemically active layer 4 using sputtering on a nickel-containing alloy, the sputtering rate can be increased compared to forming a conductive carbon layer on sintered carbon, as described in Patent Document 1. This allows for a faster film deposition rate and, consequently, improved productivity.

[0093] <Modified Examples> In the modified examples, the same reference numerals are used for components and processes as in the first embodiment, and their detailed descriptions are omitted. Furthermore, the modified examples can achieve the same effects and advantages as the first embodiment, unless otherwise specified. Moreover, the first embodiment and the modified examples can be combined as appropriate.

[0094] In the above description, the electrode 1 comprises a base film 2, a metal underlayer 3, and an electrochemically active layer 4 in order toward one side in the thickness direction. However, the electrode 1 does not necessarily have to include the metal underlayer 3. In such cases, the electrode 1 comprises a base film 2 and an electrochemically active layer 4 in order toward one side in the thickness direction. Preferably, from the viewpoint of electrochemical activity, the electrode 1 includes the metal underlayer 3.

[0095] In the above explanation, the entire surface of one side in the thickness direction of the electrochemically active layer 4 is exposed. However, a portion of the electrochemically active layer 4 may be covered, as long as it can still function as an electrode 1. In other words, it is sufficient that at least a portion of one side in the thickness direction of the electrochemically active layer 4 is exposed.

[0096] Electrode 1 may also include other layers (e.g., a hard coat layer, a gas barrier layer) besides the base film 2, the metal underlayer 3, and the electrochemically active layer 4. More specifically, electrode 1 may include other layers on other surfaces in the thickness direction of the base film 2, between the base film 2 and the metal underlayer 3, between the metal underlayer 3 and the electrochemically active layer 4, and on one surface in the thickness direction of the electrochemically active layer 4. When other layers are included on one surface in the thickness direction of the electrochemically active layer 4, the other layers are arranged such that at least a portion of that surface in the thickness direction of the electrochemically active layer 4 is exposed.

[0097] More specifically, the hard coat layer is a scratch-protective layer that makes it difficult for scratches to occur on the electrode 1. Specifically, the electrode 1 preferably has a hard coat layer on one side in the thickness direction and / or the other side in the thickness direction of the base film 2.

[0098] Furthermore, a silicon layer can be used as the gas barrier layer. Preferably, the electrode 1 has a gas barrier layer on one side in the thickness direction of the base film 2.

[0099] Furthermore, if the electrode 1 includes other layers, the thickness of the base film 2 is the thickness of the electrode 1 (μm) minus the thickness of the metal underlayer 3 (nm), the thickness of the electrochemically active layer 4 (nm), and the thickness of the other layers (nm).

[0100] In the above explanation, electrode 1 was described as an electrode for an electrochemical sensor, but it is not limited to this. It can also be used as an electrode for electrochemical measurements targeting ferrocyanine compounds, specifically as a working electrode for performing cyclic voltammetry (CV).

[0101] The present invention will be further described below with reference to examples and comparative examples. However, the present invention is not limited in any way to the examples and comparative examples. Furthermore, specific numerical values ​​such as blending ratios (content ratios), physical properties, and parameters used in the following description may be replaced with the corresponding upper limits (numerical values ​​defined as "less than or equal to" or "less than") or lower limits (numerical values ​​defined as "greater than or equal to" or") of the blending ratios (content ratios), physical properties, and parameters described in the "Modes for Carrying Out the Invention" above.

[0102] <Electrode Manufacturing> Example 1 [Preparation Process] A film made of polyethylene terephthalate (thickness: 188 μm) was prepared as the base film. The following process was carried out using a roll-to-roll method.

[0103] [Electrochemically Active Layer Placement Process] An electrochemically active layer (30 nm thick) was placed on one side of the substrate film in the thickness direction using magnetron sputtering (magnetron DC discharge). The conditions for magnetron sputtering were as follows. This process manufactured the electrode. {Conditions} Target: Nickel and chromium alloy (80% nickel by mass, 20% chromium by mass) Sputtering gas: Argon gas Transport speed: 1.5 m / min Film formation pressure: 0.20 Pa Discharge power: 5.6 W / cm ２ Film forming temperature: 40℃

[0104] Examples 2 to 7: Electrodes were manufactured following the same procedure as in Example 1. However, the conditions for each step were changed according to Table 1.

[0105] Furthermore, in Examples 5 to 7, the metal underlayer placement step was carried out after the preparation step and before the electrochemically active layer placement step.

[0106] Specifically, in the metal underlayment placement process, a niobium layer (20 nm thick) was placed on one side of the substrate film in the thickness direction using magnetron sputtering (magnetron DC discharge). The conditions for magnetron sputtering were as follows: {Conditions} Target: Niobium Sputtering gas: Argon Gas transport speed: 1.5 m / min Film formation pressure: 0.20 Pa Discharge power: 3.6 W / cm ２ Film forming temperature: 40℃

[0107] Subsequently, in the electrochemically active layer placement process, the electrochemically active layer was placed on one side in the thickness direction of the metal substrate.

[0108] Comparative Example 1 An electrode was manufactured following the same procedure as in Example 5. However, the conditions for the electrochemically active layer placement process were changed as follows: A carbon layer (thickness 5 nm) was formed on one side in the thickness direction of the metal substrate. {Conditions} Target: Sintered carbon Sputtering gas: Argon gas Transport speed: 1.5 m / min Film formation pressure: 0.20 Pa Discharge power: 7.8 W / cm ２ Film forming temperature: 40℃

[0109] <Evaluation> [Thickness] For each example and comparative example, the thickness of the metal underlayer and the electrochemically active layer in the electrodes were measured by preparing cross-sectional samples for TEM using the FIB microsampling method and observing the cross-section using a field emission transmission electron microscope (FE-TEM, JOEL Corporation, "JEM-2800"). The results are shown in Table 1.

[0110] [Productivity] For each example and comparative example electrode, the film deposition rate was calculated based on the following formula (1): Film deposition rate (nm・cm ２ Discharge power (W / cm²) * (m / min) = Thickness of electrochemically active layer (nm) / Discharge power (W / cm²) ２ ) × Conveying speed (m / min) (1)

[0111] Comparing Examples 5 to 7 and Comparative Example 1, where the thickness and transport speed of the electrochemically active layer are the same, Examples 5 to 7, which contain an alloy with nickel in the electrochemically active layer, can form the electrochemically active layer by sputtering even with low discharge power, thus increasing the film deposition rate and improving productivity.

[0112] [Electrochemical Activity] The electrochemical activity (specifically, activity towards potassium ferrocyanide) of the electrodes in each example and comparative example was evaluated.

[0113] In detail, a sample electrode with a known electrode area was prepared by attaching insulating tape with a 2 mm diameter hole to one side of the electrochemically active layer. Cyclic voltammetry (CV) was performed using this sample electrode as the working electrode. Specifically, 1 M KCl was used as the electrolyte and 1 mM KCl was used as the electrode active substance. ４ [Fe(CN)] ６The sample electrode was immersed in an aqueous solution containing potassium ferrocyanide. An Ag / AgCl electrode was used as the reference electrode and a Pt electrode as the counter electrode. In the CV measurement, the potential was swept from negative to positive in the range of -0.1 to 0.5 V (specifically, the potential was changed in the order of -0.1 V, 0.5 V, and -0.1 V). The potential sweep rate was 0.1 V / s. The CV measurement was performed at 23°C. Three CV measurements were performed. The average value of the three ΔEp values ​​in the CV measurement was obtained as ΔEp. A smaller ΔEp indicates a faster electron transfer rate and better activity towards potassium ferrocyanide. The results are shown in Table 1.

[0114]

[0115] The above invention is provided as an illustrative embodiment of the present invention, but this is merely illustrative and should not be interpreted restrictively. Modifications of the present invention that are obvious to those skilled in the art are included in the claims below.

[0116] The electrode, electrochemical sensor, biosensor, and method for manufacturing the electrode according to the present invention can be suitably used, for example, in the manufacture of blood glucose sensors.

[0117] 1. Electrode 2. Substrate film 4. Electrochemically active layer

Claims

1. An electrode comprising a base film and an electrochemically active layer having electrochemical activity, arranged sequentially toward one side in the thickness direction, wherein the electrochemically active layer contains a nickel-containing alloy, and at least a portion of one side of the electrochemically active layer in the thickness direction is exposed.

2. The electrode according to claim 1, wherein the electrochemically active layer comprises an alloy of nickel and chromium, and the nickel content is 70% by mass or more and 97% by mass or less relative to the alloy.

3. The electrode according to claim 1, further comprising a metal underlayer between the base film and the electrochemically active layer.

4. An electrochemical sensor comprising the electrode described in any one of claims 1 to 3.

5. A biosensor comprising the electrode described in any one of claims 1 to 3.

6. A method for manufacturing an electrode, comprising: a preparation step of preparing a base film; and an electrochemically active layer placement step of placing an electrochemically active layer having electrochemical activity on one side of the base film in the thickness direction, wherein the electrochemically active layer placement step is carried out by a roll-to-roll method, and the electrochemically active layer contains an alloy containing nickel.

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