Electrode and method for manufacturing electrode

Abstract

An electrode including a film including metal cation-containing layered material particles having a single layer or a plurality of layers and having a metal cation, and a conductive gel portion in contact with the film, the layer includes a layer body represented by the following formula, and a modification or terminal T (T is at least one selected from the group consisting of a hydroxyl group, a fluorine atom, a chlorine atom, an oxygen atom, and a hydrogen atom) present on a surface of the layer body, MmXn (in the formula, M is at least one of metals of groups 3, 4, 5, 6, and 7, and includes at least a Ti atom, X is a carbon atom, a nitrogen atom, or a combination thereof, and n is an integer of 1-3). N is 1-4 (inclusive) and m is greater than n and is 5 or less), and the content of the metal cations is 0.004 mol or more per 1 g of the film.

Description

Technical Field

[0001] The present disclosure relates to electrodes and methods of making electrodes. Background Art

[0002] In recent years, MXene has attracted considerable attention as a novel material. MXene is a so-called two-dimensional material. As described later, it is a layered material with a single or multilayer morphology. Generally speaking, MXene takes the form of particles of the layered material (hereinafter referred to as "layered material particles," which may include powders, flakes, nanosheets, etc.).

[0003] Currently, various studies are underway on the application of MXene in various fields. For example, applications such as electrodes in electrical equipment, electromagnetic shielding (EMI shielding), and the like that require maintaining high conductivity are being considered. For example, non-patent document 1 states that Ti3C2MXene, as a two-dimensional material, is a material that is significantly different from carbon-based nanomaterials. Ti3C2MXene microelectrodes exhibit excellent low impedance compared to existing metal microelectrodes and are suitable for recording neural signals from organisms such as the brain. In addition, non-patent document 2 also discloses that MXene can be effective in many applications in the field of organisms, such as mapping a wide range of neuromuscular networks in humans and cortical microstimulation in small animal models.

[0004] Prior art literature

[0005] Non-patent literature

[0006] Non-Patent Literature 1: Driscoll, Nicolette, et al. “Two-dimensional Ti3C2 MXene for high-resolution neural interfaces” ACS nano 12.10 (2018): 10419-10429

[0007] Non-patent document 2: Driscoll, Nicolette, et al. "MXene-infused bioelectronic interfaces for multiscale electrophysiology and stimulation" SCIENCETRANSLATIONAL MEDICINE (2021) Summary of the Invention

[0008] Problems to be solved by the invention

[0009] For example, when performing high-resolution sensing in the biological field, it is important to minimize the interfacial impedance of the electrode. Some of the electrodes described above have a conductive gel provided on a conductive film. However, in the case of an electrode provided with a conductive gel, it is difficult to reduce the impedance of the electrode. In the electrodes containing MXene described in Non-Patent Documents 1 and 2, it is believed that improvements are needed for this purpose. The present disclosure is proposed in view of the above situation, and its purpose is to provide a low-impedance electrode provided with a conductive gel and a method for manufacturing the same.

[0010] Solutions for solving problems

[0011] According to one aspect of the present invention, there is provided the following electrode:

[0012] The electrode comprises a membrane and a conductive gel portion in contact with the membrane, wherein the membrane comprises layered material particles containing metal cations.

[0013] The metal cation-containing layered material particles have a single layer or multiple layers and contain metal cations,

[0014] The layer includes a layer body represented by the following formula, and a modification or terminal T (T is at least one selected from the group consisting of a hydroxyl group, a fluorine atom, a chlorine atom, an oxygen atom, and a hydrogen atom) present on the surface of the layer body,

[0015] M m X n

[0016] (wherein, M is at least one of Group 3, 4, 5, 6, and 7 metals, and contains at least Ti atoms,

[0017] X is a carbon atom, a nitrogen atom or a combination thereof,

[0018] n is 1 or more and 4 or less,

[0019] m is greater than n and less than 5)

[0020] The content of the metal cation is 0.004 mol or more per 1 g of the film.

[0021] According to another aspect of the present invention, there is provided a method for manufacturing an electrode.

[0022] The manufacturing method comprises the following steps:

[0023] (a) preparing a layered material particle, the layered material particle comprising a single layer or multiple layers,

[0024] The layer includes a layer body represented by the following formula, and a modification or terminal T (T is at least one selected from the group consisting of a hydroxyl group, a fluorine atom, a chlorine atom, an oxygen atom, and a hydrogen atom) present on the surface of the layer body,

[0025] M m X n

[0026] (wherein, M is at least one of Group 3, 4, 5, 6, and 7 metals, and contains at least Ti atoms,

[0027] X is a carbon atom, a nitrogen atom or a combination thereof,

[0028] n is 1 or more and 4 or less,

[0029] m is greater than n and less than 5);

[0030] (b) mixing the dispersion containing the layered material particles with an aqueous solution containing metal cations to obtain a dispersion containing layered material particles containing metal cations;

[0031] (c) using the dispersion containing the metal cation-containing layered material particles to obtain a film containing the metal cation-containing layered material particles, wherein the content of the metal cation is 0.004 mol or more per 1 g of the film; and

[0032] (d) forming a conductive gel portion on at least one surface of the film.

[0033] Effects of the Invention

[0034] According to the present disclosure, a film of particles of a predetermined layered material (also referred to herein as "MXene") contained in an electrode contains a predetermined amount or more of metal cations, thereby providing an electrode comprising MXene, exhibiting low impedance, and provided with a conductive gel. Furthermore, a method for easily manufacturing the electrode is provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a schematic cross-sectional view of MXene constituting a film included in the electrode of this embodiment. DETAILED DESCRIPTION

[0036] (Embodiment 1: Electrode)

[0037] The electrode in one embodiment of the present invention is described in detail below, but the present disclosure is not limited to the relevant embodiment.

[0038] The electrode in this embodiment includes a membrane and a conductive gel portion in contact with the membrane, wherein the membrane includes layered material particles containing metal cations.

[0039] The metal cation-containing layered material particles have a single layer or multiple layers and contain metal cations,

[0040] The layer includes a layer body represented by the following formula, and a modification or terminal T (T is at least one selected from the group consisting of a hydroxyl group, a fluorine atom, a chlorine atom, an oxygen atom, and a hydrogen atom) present on the surface of the layer body,

[0041] M m X n

[0042] (wherein, M is at least one of Group 3, 4, 5, 6, and 7 metals, and contains at least Ti atoms,

[0043] X is a carbon atom, a nitrogen atom or a combination thereof,

[0044] n is 1 or more and 4 or less,

[0045] m is greater than n and less than 5)

[0046] The content of the metal cation is 0.004 mol or more per 1 g of the film. This makes it possible to realize an electrode comprising MXene, exhibiting low impedance, and provided with a conductive gel.

[0047] The following describes a film (sometimes referred to as a "MXene film containing metal cations" or "conductive film") comprising layered material particles (layered material particles containing metal cations) constituting the electrode of this embodiment. The layered material particles comprise a single layer or multiple layers and contain metal cations. The layered material can be understood as a layered compound and can also be represented as "MXene film". m X n T s ", s is an arbitrary number. In the past, x or z was sometimes used instead of s. Typically, n can be 1, 2, 3 or 4, but is not limited to these.

[0048] In the above formula of MXene, M may be Ti alone, or may contain Ti and further contain at least one selected from the group consisting of Zr, Hf, V, Nb, Ta, Cr, Mo, and Mn. When M contains an element other than Ti, the element other than Ti is more preferably at least one selected from the group consisting of V, Cr, and Mo.

[0049] As MXene, the above formula: M m X n The following substances can be mentioned.

[0050] Ti2C, Ti2N, (Ti, V)2C, (Ti, Nb)2C,

[0051] Ti3 C2, Ti3N2, Ti3(CN), (Ti, V)3C2, (Ti2Nb)C2, (Ti2Ta)C2, (Ti2Mn)C2, (V2Ti)C2, (Cr2Ti)C2, (Mo2Ti)C2, (W2Ti)C2,

[0052] Ti4N3, (Ti, Nb)4C3, (Ti2Nb2)C3, (Ti2Ta2)C3, (V2Ti2)C3, (Cr2Ti2)C3, (Mo2Ti2)C3, (W2Ti2)C3

[0053] Typically, in the above formula, M is titanium, or titanium and vanadium, and X can be a carbon atom or a nitrogen atom. For example, MAX phase is Ti3AlC2, and MXene is Ti3C2T s (In other words, M is Ti, X is C, n is 2, and m is 3).

[0054] It should be noted that in this embodiment, the MXene may contain a relatively small amount of residual A atoms, for example, 10% by mass or less relative to the original A atoms. The residual amount of A atoms may preferably be 8% by mass or less, and more preferably 6% by mass or less. However, even if the residual amount of A atoms exceeds 10% by mass, there may be no problem depending on the application and usage conditions of the electrode.

[0055] The following uses Figure 1 The MXene constituting the layered material particles (MXene particles) will be described. The metal cation-containing layered material particles (MXene particles containing metal cations) according to this embodiment have substantially the same skeleton as the layered material particles (MXene particles). Figure 1 The structure equivalent to the skeleton of MXene particles containing metal cations is described in Figure 1 Metal cations are not shown.

[0056] The layered material particles (MXene particles) involved in this embodiment are composed of multiple Figure 1 (a) schematically illustrates an aggregate of single-layer MXene 10a (single-layer MXene) (however, as mentioned above, no metal cations are shown). More specifically, MXene 10a is a m X n The layer body represented by m X n The MXene layer 7a includes a modified or terminal MXene layer 1a and a modified or terminal MXene layer 7a present on the surface of the layer body 1a (more specifically, at least one of the two surfaces facing each other in each layer). Therefore, the MXene layer 7a is also represented as "MXene layer". m X nT s ", s is an arbitrary number.

[0057] The MXene particles involved in this embodiment can be single-layer or multi-layer MXene. As a multi-layer MXene (multi-layer MXene), Figure 1 As schematically shown in (b), two layers of MXene10b can be listed, but the examples are not limited to these. Figure 1 1b, 3b, 5b, 7b in (b) and the above Figure 1 1a, 3a, 5a, and 7a in (a) are the same. Two adjacent MXene layers (for example, 7a and 7b) of a multilayer MXene are not necessarily completely separated and may be in partial contact. The MXene10a is the multilayer MXene10b separated layer by layer and exists as a single layer. Sometimes, there is a multilayer MXene10b that has not been separated, which is a mixture of the single-layer MXene10a and the multilayer MXene10b. Even in the case of containing the multilayer MXene, it is preferably a MXene with a small number of layers obtained by interlayer exfoliation of the multilayer MXene. The "small number of layers" means that, for example, the number of stacking layers of MXene is less than 10 layers. Hereinafter, this "multilayer MXene with a small number of layers" is sometimes referred to as "few-layer MXene". The thickness of the few-layer MXene in the stacking direction can be less than 15 nm, and further can be less than 10 nm. In addition, single-layer MXene and few-layer MXene are sometimes collectively referred to as "single-layer / few-layer MXene".

[0058] The above-mentioned MXene can be mostly single-layer / few-layer MXene. By making the MXene mostly single-layer / few-layer MXene, the specific surface area of ​​the MXene can be made larger than that of the multilayer MXene. As a result, when the laminate is used for applications requiring conductivity, for example, the degradation of conductivity over time can be suppressed. For example, the proportion of single-layer / few-layer MXene with a stacking number of MXene layers of 10 or less and a thickness of 15 nm or less, preferably 10 nm or less, in all MXene can be, for example, 80% by volume or more, further 90% by volume or more, and further 95% by volume or more. In addition, the volume of the single-layer MXene can be greater than that of the few-layer MXene. The true density of these MXenes does not change significantly due to the presence of morphology, so it can also be said that the mass of the single-layer MXene is greater than that of the few-layer MXene. In the presence of these relationships, the specific surface area of ​​the MXene can be increased, and when used for the above-mentioned applications requiring conductivity, the degradation of conductivity over time can be suppressed. For example, a film can be formed from only a single-layer MXene.

[0059] Although not limited to this embodiment, the thickness of each MXene layer (equivalent to the above-mentioned MXene layers 7a and 7b) can be set to, for example, 1 nm or more and 30 μm or less, for example, 1 nm or more and 5 nm or less, or further 1 nm or more and 3 nm or less (mainly depending on the number of M atomic layers contained in each layer). For each stack of multi-layer MXene that can be included, the interlayer distance (or gap size, Figure 1 The thickness (represented by Δd in (b)) is, for example, 0.8 nm to 10 nm, particularly 0.8 nm to 5 nm, more particularly about 1 nm, and the total number of layers can be 2 to 20,000.

[0060] As the name implies, the metal cation-containing layered material particles contain metal cations. The type of metal cation is not limited, but considering ease of intercalation between layers of the layered material particles, alkali metal cations are preferred, and at least one of Li, Na, and K cations is more preferred. The metal cation is particularly preferably at least one of Li, Na, and K cations.

[0061] The content of the metal cation is 0.004 mol (0.004 mol / g) or more per 1g of the film containing the layered material particles containing metal cations (MXene film containing metal cations, conductive film). It can be considered that a large amount of metal cations will be intercalated between the layers of MXene. By having a certain abundance of metal cations or more in the MXene film as a precursor film, it is possible to prevent the diffusion of ions from a medium containing ions such as a conductive gel. Although the present disclosure is not subject to any theoretical constraints, it can be considered that by making the content of the metal cations more than a certain amount, the following effects will be exerted. That is, when discharging from a capacitor to an electrode, it was previously believed that the ions in the conductive gel of the electrode intercalated into the MXene, and an ion offset occurred between the electrodes, and the potential between the electrodes became larger. However, by making the content of the metal cations more than 0.004 mol / g and enriching ions in MXene in advance, it is possible to suppress the further intercalation of ions caused by the discharge from the capacitor, suppress the offset of ions between the electrodes, and suppress the increase in the potential between the electrodes. The content of the metal cation is preferably 0.006 mol or more per 1 g of the film containing the layered material particles containing the metal cations. A higher content of the metal cation is more preferred, but from the perspective of ease of manufacture, the content can be set to 0.1 mol or less (0.1 mol / g or less) per 1 g of the film containing the layered material particles containing the metal cations. The content of the metal cation can also be further set to 0.05 mol / g or less.

[0062] The electrode according to this embodiment includes at least the film and the conductive gel portion. The electrode may be formed only of the conductive film and the conductive gel portion, or may include the conductive film, the conductive gel portion, and, for example, a substrate.

[0063] The conductive gel portion of the electrode of this embodiment can be composed of a gel material in which water, a solvent such as a moisturizer, and a conductive material are retained in a three-dimensional polymer matrix. As this gel material, for example, Technogel (registered trademark) manufactured by Sekisui Chemicals Co., Ltd. can be used.

[0064] Examples of the electrode of this embodiment include solid electrodes and flexible soft electrodes.

[0065] In the case where the electrode of the present embodiment has a substrate, the film and the substrate may be in direct contact. The material of the substrate is not particularly limited. The substrate may be formed of a conductive material, for example. As the conductive material, at least one material selected from the group consisting of gold, silver, copper, platinum, nickel, titanium, tin, iron, zinc, magnesium, aluminum, tungsten, molybdenum and conductive polymers as metal materials may be listed. The substrate may have a conductive film, such as a metal film, which is different from the conductive film involved in the present embodiment, on the contact surface with the conductive film involved in the present embodiment. Alternatively, the substrate may be formed of an organic material. As the organic material, for example, a flexible organic material may be listed, for example, a thermoplastic polyurethane elastomer (TPU), a PET film, a polyimide film, etc.

[0066] (Application of electrodes)

[0067] The electrodes of this embodiment can be used for any suitable purpose. There is no particular limitation on this, and can be, for example, biological signal sensing electrodes, capacitor electrodes, battery electrodes, sensor electrodes, etc. The details of these uses are described below.

[0068] Biosignal sensing electrodes are electrodes used to acquire biosignals. Examples of biosignal sensing electrodes include, but are not limited to, electrodes used to measure ECG (electrocardiogram), EEG (electroencephalogram), EMG (electromyogram), and EIT (electrical impedance tomography).

[0069] The capacitor may be an electrochemical capacitor. An electrochemical capacitor is a capacitor that utilizes the capacitance exhibited by the physicochemical reaction between electrodes (electrode active materials) and ions (electrolyte ions) in an electrolyte solution and can be used as a device for storing electrical energy (electrical storage device). The battery may be a chemical battery that can be repeatedly charged and discharged. Examples of the battery include, but are not limited to, Li-ion batteries, magnesium-ion batteries, lithium-sulfur batteries, and Na-ion batteries.

[0070] The sensor electrode is an electrode used to detect a target substance, state, abnormality, etc. Examples of the sensor include, but are not limited to, a gas sensor and a biosensor (a chemical sensor utilizing a molecular recognition mechanism derived from a living organism).

[0071] The electrode of this embodiment is preferably used as a biological signal sensing electrode. As described above, when used as a disposable electrocardiogram electrode, for example, an electrode comprising a membrane composed of metal cation-rich MXene and a conductive gel portion is considered to exhibit low impedance due to minimal ion migration between the electrodes during capacitor discharge. Consequently, it is believed that sensitivity is enhanced when used as a biological signal sensing electrode.

[0072] (Embodiment 3: Method for manufacturing an electrode)

[0073] The method for manufacturing the electrode according to this embodiment will now be described in detail, but the present disclosure is not limited to this embodiment.

[0074] A method for manufacturing an electrode (first manufacturing method) according to this embodiment includes the following steps:

[0075] (a) preparing a layered material particle, the layered material particle comprising a single layer or multiple layers,

[0076] The layer includes a layer body represented by the following formula, and a modification or terminal T (T is at least one selected from the group consisting of a hydroxyl group, a fluorine atom, a chlorine atom, an oxygen atom, and a hydrogen atom) present on the surface of the layer body,

[0077] M m X n

[0078] (wherein, M is at least one of Group 3, 4, 5, 6, and 7 metals, and contains at least Ti atoms,

[0079] X is a carbon atom, a nitrogen atom or a combination thereof,

[0080] n is 1 or more and 4 or less,

[0081] m is greater than n and less than 5);

[0082] (b) mixing the dispersion containing the layered material particles with an aqueous solution containing metal cations to obtain a dispersion containing layered material particles containing metal cations;

[0083] (c) using the dispersion containing the metal cation-containing layered material particles to obtain a film containing the metal cation-containing layered material particles, wherein the content of the metal cation is 0.004 mol or more per 1 g of the film; and

[0084] (d) forming a conductive gel portion on at least one surface of the film.

[0085] Another method for manufacturing an electrode (second manufacturing method) according to this embodiment is a method for manufacturing an electrode having the following steps:

[0086] (A) preparing a layered material particle comprising a single layer or multiple layers,

[0087] The layer includes a layer body represented by the following formula, and a modification or terminal T (T is at least one selected from the group consisting of a hydroxyl group, a fluorine atom, a chlorine atom, an oxygen atom, and a hydrogen atom) present on the surface of the layer body,

[0088] M m X n

[0089] (wherein, M is at least one of Group 3, 4, 5, 6, and 7 metals, and contains at least Ti atoms,

[0090] X is a carbon atom, a nitrogen atom or a combination thereof,

[0091] n is 1 or more and 4 or less,

[0092] m is greater than n and less than 5);

[0093] (B) using the dispersion containing the layered material particles to obtain a precursor film containing the layered material particles;

[0094] (C) contacting the precursor film with an aqueous solution containing metal cations, thereby obtaining a film containing layered material particles containing metal cations, wherein the content of the metal cations is 0.004 mol or more per 1 g of the film; and

[0095] (D) A conductive gel portion is formed on at least one surface of the film.

[0096] The following describes in detail each step of the first and second production methods. Steps (a) and (A), and steps (d) and (D) common to both production methods are summarized and described.

[0097] ·Process (a) and process (A)

[0098] First, a predetermined precursor is prepared. The predetermined precursor that can be used in this embodiment is a MAX phase, which is a precursor of MXene and is represented by the following formula:

[0099] M m AX n

[0100] (wherein, M is at least one of Group 3, 4, 5, 6, and 7 metals and includes Ti,

[0101] X is a carbon atom, a nitrogen atom or a combination thereof,

[0102] A is at least one of the elements of Groups 12, 13, 14, 15, and 16,

[0103] n is 1 or more and 4 or less,

[0104] m is greater than n and is 5 or less).

[0105] The above-mentioned M, X, n, and m are as described for MXene. A is at least one element selected from Groups 12, 13, 14, 15, and 16, usually a Group A element, typically Groups IIIA and IVA. More specifically, it may include at least one element selected from the group consisting of Al, Ga, In, Tl, Si, Ge, Sn, Pb, P, As, S, and Cd, preferably Al.

[0106] The MAX phase has a layer composed of A atoms located on a m X n The MAX phase has a crystal structure between two layers (which may have a lattice in which each X is located in an octahedral array of M). Typically, when m=n+1, a layer of X atoms is arranged between each layer of n+1 layers of M atoms (these layers are also collectively referred to as "M m X n As a layer next to the n+1th layer of M atoms, a layer of A atoms ("A atomic layer") is arranged, but the present invention is not limited thereto.

[0107] The MAX phase can be produced by known methods. For example, TiC powder, Ti powder, and Al powder are mixed in a ball mill and sintered in an Ar atmosphere to obtain a sintered body (massive MAX phase). The sintered body is then pulverized with an end mill to obtain a powdered MAX phase for the next step.

[0108] By selectively etching (removing and optionally separating) the A atoms (and optionally a part of the M atoms) from the MAX phase, the A atom layer (and optionally a part of the M atoms) is removed, and the hydroxyl groups, fluorine atoms, chlorine atoms, oxygen atoms, hydrogen atoms, etc. present in the etching solution (usually, an aqueous solution containing fluorine acid is used, but not limited thereto) have an effect on the exposed M atoms. m X n The surface of the layer is modified to end-cap the surface.

[0109] The above etching can be performed using a -The etching solution can be used for implementation, for example, a method using a mixed solution of lithium fluoride and hydrochloric acid, a method using hydrofluoric acid, etc. The etching solution contains a metal compound containing a monovalent metal ion, and an intercalation treatment of the monovalent metal ion can be performed simultaneously with the above-mentioned etching. Examples of metal compounds containing monovalent metal ions include compounds used in the following intercalation treatment. The content of the metal compound containing a monovalent metal ion in the etching solution is preferably 0.001% by mass or more. The above content is more preferably 0.01% by mass or more, and further preferably 0.1% by mass or more. On the other hand, from the perspective of dispersibility in the solution, the content of the metal compound containing a monovalent metal ion in the etching solution is preferably set to 10% by mass or less, and more preferably 1% by mass or less.

[0110] After the etching, any suitable post-treatment (e.g., ultrasonic treatment, hand shaking or automatic shaking) can be used to appropriately promote the layer separation (delamination, separating multilayer MXene into single-layer MXene) of MXene. It should be noted that with ultrasonic treatment, excessive shear force may damage the MXene. Therefore, when it is desired to obtain a two-dimensional MXene with a larger aspect ratio (preferably a single-layer MXene), it is preferred to apply appropriate shear force by hand shaking or automatic shaking.

[0111] To separate the MXene layers, intercalation and delamination can be performed as described below.

[0112] (Intercalation treatment)

[0113] For example, an intercalation treatment of a monovalent metal ion can be performed, which includes a process of mixing the etched product obtained by the etching treatment with a metal compound containing a monovalent metal ion. As the monovalent metal ions constituting the metal compound containing a monovalent metal ion, alkali metal ions such as Li ions, Na ions and K ions, copper ions, silver ions, gold ions, etc. can be listed. As the metal compound containing a monovalent metal ion, ionic compounds in which the above-mentioned metal ions are combined with cations can be listed. For example, iodides, phosphates, sulfide salts including sulfates, nitrates, acetates, and carboxylates of the above-mentioned metal ions can be listed. As the monovalent metal ion, as mentioned above, Li ions are preferably used. As the metal compound containing a monovalent metal ion, Li ions are preferably used. Li ions are more preferably used as ionic compounds of Li ions, and more preferably Li ions are used as iodides, phosphates, and sulfide salts. If Li ions are used as metal ions, it is believed that water hydrated with Li ions has the most negative dielectric constant, so it is easy to form a monolayer.

[0114] The content of the metal compound containing a monovalent metal ion in the mixture for intercalation treatment of monovalent metal ions is preferably set to 0.001% by mass or more. The above content is more preferably 0.01% by mass or more, and even more preferably 0.1% by mass or more. On the other hand, from the perspective of dispersibility in solution, the content of the metal compound containing a monovalent metal ion is preferably set to 10% by mass or less, and more preferably 1% by mass or less.

[0115] (Layered)

[0116] The use of the intercalation treatment product obtained by intercalation for stratification can be listed. For example, the following stratification can be listed, which includes centrifuging the intercalation treatment product and washing the remaining precipitate with water after discarding the supernatant. The conditions for the stratification treatment are not particularly limited. There is no particular limitation on the dispersion medium used for stratification. For example, the use of one or more polar organic dispersion media and aqueous dispersion media can be listed. It can be listed that one or more of the polar organic dispersion medium and the aqueous dispersion medium are added and stirred, and centrifuged, the supernatant is recovered, and the above operation is repeated more than once, preferably more than twice and less than 10 times, to obtain a supernatant containing a single layer / few layers of MXene as a stratified treatment product. Alternatively, the supernatant can be centrifuged and the supernatant after centrifugation is discarded to obtain clay containing a single layer / few layers of MXene as a stratified treatment product.

[0117] Process (b)

[0118] In the first production method, a dispersion containing the layered material particles is mixed with an aqueous solution containing metal cations to obtain a dispersion containing the layered material particles containing metal cations.

[0119] The dispersion containing the layered material particles can be obtained, for example, by stirring and mixing the clay containing the monolayer / few-layer MXene obtained in the above separation with an aqueous dispersion medium such as pure water to obtain a slurry containing the layered material particles.

[0120] There is no limitation on the type of metal cations contained in the aqueous solution containing metal cations, but considering the ease of intercalation between the layers of the layered material particles, cations of alkali metals are preferred, and at least one of Li cations, Na cations, and K cations is more preferred. The metal cation is particularly preferably at least one of Li cations, Na cations, and K cations. Regarding the concentration of the metal cations in the aqueous solution containing metal cations, the amount of metal cations per 1 g of the final film obtained is 0.004 mol or more, and there is no particular limitation. From the perspective of being easy to mix with the dispersion containing the layered material particles and intercalating the metal cations between the layers of the layered material particles, it is preferred to use an aqueous solution containing 10% to 30% by mass of metal cations, such as chlorides, fluorides, bromides, iodides, sulfates, nitrates, phosphates, and the like.

[0121] There is no particular limitation on the method for mixing the dispersion containing the layered material particles and the aqueous solution containing the metal cations, and stirring can be performed using a known method. Furthermore, there is no particular limitation on the liquid temperature during mixing, and it can be room temperature.

[0122] Process (c)

[0123] In the first manufacturing method, a film containing particles of layered material containing metal cations is obtained using the dispersion of the particles of layered material containing metal cations. When forming the film, a dispersion of MXene containing metal cations, such as a MXene slurry containing metal cations obtained by diluting the clay containing MXene containing metal cations with a medium liquid, can be used. The dispersion can also be a suspension. There is no particular limitation on the method for forming a film using a dispersion of MXene containing metal cations. The dispersion of MXene containing metal cations can be applied to a substrate directly or after appropriate adjustment (for example, dilution with a medium liquid or addition of a binder). As coating methods, for example, methods of spraying using nozzles such as a single-fluid nozzle, a two-fluid nozzle, and an airbrush (methods using a spray coater) can be listed; methods such as slit coating using a desktop coater, a comma coater, and a rod coater, screen printing, metal mask printing, etc.; spin coating, dip coating, dripping, etc. As the above-mentioned medium liquid, aqueous medium liquid and organic medium liquid can be listed. The medium liquid constituting the dispersion of the metal cation-containing MXene is typically water. Depending on the circumstances, it may contain a relatively small amount (e.g., 30% by mass or less, preferably 20% by mass or less, based on the total amount) of other liquid substances in addition to water. Examples of the organic medium liquid include N-methylpyrrolidone, N-methylformamide, N,N-dimethylformamide, ethanol, methanol, dimethyl sulfoxide, ethylene glycol, and acetic acid.

[0124] When forming using a spray coater, for example, the atomization pressure is set to 0.1 MPa to 0.5 MPa, the distance between the nozzle tip and the substrate is set to 10 cm to 25 cm, the liquid feed rate is set to 0.1 mL / s to 10 mL / s, the scanning speed is set to 1 mm / s to 30 mm / s, and the stage heater is set to 30°C to 60°C. The MXene slurry containing metal cations is applied to a substrate such as PET or polyimide once or multiple times to form a film (electrode) before drying.

[0125] In addition to making a membrane by the above-mentioned spraying, a membrane can also be made by filtering the MXene slurry containing metal cations. In more detail, the concentration of the MXene slurry containing metal cations is appropriately adjusted (for example, diluted with an aqueous medium liquid as needed), and filtered through a filter provided in a suction funnel (Nutsche) or the like (even if it constitutes a prescribed component together with the MXene membrane containing metal cations, it can eventually be separated from the MXene membrane containing metal cations) to remove at least part of the aqueous medium liquid, thereby forming a membrane on the filter. There is no particular limitation on the filter, and a membrane filter or the like can be used.

[0126] The substrate may or may not be present. In the case of a substrate, the material constituting the substrate is not particularly limited and may be composed of any suitable material. The substrate may be, for example, a resin film, a metal foil, a printed circuit board, a mounted electronic component, a metal needle, a metal wiring, a metal wire, etc. For example, a substrate formed of a metal material, a resin, etc. suitable for a biological signal sensing electrode may be appropriately adopted. By coating on any suitable substrate (even if it constitutes a prescribed component together with the MXene film containing metal cations, it can eventually be separated from the MXene film containing metal cations), a MXene film containing metal cations can be formed on the substrate.

[0127] Drying can be carried out under mild conditions such as natural drying (typically placed in an air atmosphere at room temperature and pressure), air drying (blowing air), or under more active conditions such as warm air drying (blowing heated air), heat drying and / or vacuum drying. In this embodiment, "drying" refers to removing the dielectric liquid that may be present in the film. The drying can be carried out, for example, using a normal pressure oven or a vacuum oven at a temperature below 400°C. For example, drying can be carried out at a temperature of 30°C or above and 200°C or below for 30 minutes or more and 24 hours or less.

[0128] The formation and drying of the metal cation-containing MXene film can be repeated as appropriate until the desired film thickness is achieved. For example, the combination of spraying and drying can be repeated multiple times. The liquid component of the liquid medium from the slurry may remain on the metal cation-containing MXene film or may be substantially absent.

[0129] Process (B)

[0130] In the second manufacturing method, a dispersion containing the layered material particles is used to obtain a precursor film containing the layered material particles. When forming the precursor film, a dispersion of layered material particles (MXene particles) such as MXene slurry obtained by diluting the above-mentioned clay containing a single layer / few layers of MXene with a medium liquid can be used. The dispersion liquid can also be a suspension. There is no particular limitation on the method for forming a precursor film using a dispersion of MXene particles. The dispersion of MXene particles can be applied to a substrate directly or after appropriate adjustment (for example, dilution with a medium liquid or addition of a binder). As a coating method, for example, a method of spraying using a nozzle such as a single-fluid nozzle, a two-fluid nozzle, an air brush, etc. (a method using a spray coater); methods such as slit coating using a desktop coater, a comma coater, and a rod coater, screen printing, metal mask printing, etc.; spin coating, dip coating, dripping, etc. As the above-mentioned medium liquid, an aqueous medium liquid and an organic medium liquid can be listed. The medium liquid constituting the dispersion of the MXene particles is typically water. Depending on the circumstances, it may contain a relatively small amount (e.g., 30% by mass or less, preferably 20% by mass or less, based on the total mass) of other liquid substances in addition to water. Examples of the organic medium liquid include N-methylpyrrolidone, N-methylformamide, N,N-dimethylformamide, ethanol, methanol, dimethyl sulfoxide, ethylene glycol, and acetic acid.

[0131] When a spray coater is used, for example, the atomization pressure is set to 0.1 MPa to 0.5 MPa, the distance between the nozzle tip and the substrate is set to 10 cm to 25 cm, the liquid feed rate is set to 0.1 mL / s to 10 mL / s, the scanning speed is set to 1 mm / s to 30 mm / s, and the hot stage is set to 30°C to 60°C. The MXene slurry is applied to a substrate such as PET or polyimide once or multiple times to form a film before drying.

[0132] In addition to making a precursor film by the above-mentioned spraying, a precursor film can also be made by filtering the above-mentioned slurry or the supernatant containing MXene particles obtained by the above-mentioned layering. In more detail, for example, a supernatant containing MXene particles as a dispersion of MXene particles, appropriate adjustments are made (for example, diluted with an aqueous medium liquid), and a filter is provided in a suction filtration funnel or the like (even if it constitutes a prescribed component together with the precursor film, it can eventually be separated from the precursor film) to remove at least part of the aqueous medium liquid, thereby enabling a precursor film to be formed on the filter. There is no particular limitation on the filter, and a membrane filter or the like can be used. By the above-mentioned filtration, a precursor film can be made without using the binder or the like. If the MXene particles of the present embodiment are used, a precursor film can be made without using a binder or the like.

[0133] The substrate may or may not be present. In the case of a substrate, the material constituting the substrate is not particularly limited and may be composed of any suitable material. The substrate may be, for example, a resin film, a metal foil, a printed circuit board, a mounted electronic component, a metal needle, a metal wiring, a metal wire, etc. For example, a substrate formed of a metal material, a resin, etc. suitable for a biological signal sensing electrode may be appropriately adopted. By coating on any suitable substrate (even if it constitutes a prescribed component together with the precursor film, it may eventually be separated from the precursor film), a precursor film may be formed on the substrate.

[0134] Drying can be carried out under mild conditions such as natural drying (typically placed in an air atmosphere at room temperature and pressure), air drying (blowing air), or under more active conditions such as warm air drying (blowing heated air), heat drying and / or vacuum drying. In this embodiment, "drying" refers to removing the medium liquid that may be present in the precursor film. The drying can be carried out, for example, using a normal pressure oven or a vacuum oven at a temperature below 400°C. For example, drying can be carried out at a temperature of 30°C or above and 200°C or below for 30 minutes or more and 24 hours or less.

[0135] The formation and drying of the precursor film can be repeated as appropriate until the desired precursor film thickness is obtained. For example, the combination of spraying and drying can be repeated multiple times. By using the above-mentioned suction filtration, a precursor film can be formed without the presence of a binder. The liquid component of the liquid medium from the slurry may remain on the precursor film or may be substantially absent.

[0136] Process (C)

[0137] In the second production method, the precursor film is brought into contact with an aqueous solution containing metal cations to obtain a film containing layered material particles containing metal cations (metal cation-containing MXene film).

[0138] There is no limitation on the type of metal cations contained in the aqueous solution containing metal cations, but considering the ease of intercalation between the layers of the layered material particles, cations of alkali metals are preferred, and at least one of Li cations, Na cations and K cations is more preferred. The metal cation is particularly preferably at least one of Li cations, Na cations and K cations. Regarding the concentration of the metal cations in the aqueous solution containing metal cations, the metal cations per 1g of the final film obtained can be 0.004 mol or more, and there is no particular limitation. From the perspective of easy contact with the precursor film and intercalation of the metal cations between the layers of the layered material particles, it is preferred to use an aqueous solution containing 50 to 95% by mass of metal cations such as chlorides, fluorides, bromides, iodides, sulfates, nitrates, phosphates, etc. at a saturated solubility of each at 25°C.

[0139] The temperature of the aqueous solution containing metal cations when in contact with the precursor film can be set to room temperature (normal temperature). The method for contacting the precursor film with the aqueous solution containing metal cations is not particularly limited. In addition to immersing the precursor film in the aqueous solution containing metal cations, methods such as spraying the precursor film using a nozzle to contact the entire surface or a portion of at least one side of the precursor film can be used. The contact time (in the case of immersion, the immersion time) can be set to, for example, 30 minutes to 24 hours.

[0140] ·Process (d) and process (D)

[0141] A conductive gel portion is formed on at least one side of the resulting metal cation-containing MXene film. The conductive gel can be the conductive gel contained in the aforementioned electrode. The conductive gel is formed on at least one side of the metal cation-containing MXene film by coating, laminating, or the like. As desired, the portion of at least one side of the film where the conductive gel portion is formed can be the entire surface or a portion thereof.

[0142] While the electrode in one embodiment of the present disclosure has been described in detail above, the present disclosure may be modified in various ways. It should be noted that the electrode of the present disclosure may also be manufactured by a method different from the manufacturing method in the above embodiment.

[0143] Example

[0144] The present invention is further described below by way of examples. The present invention is not limited to the following examples, and can be implemented with appropriate modifications within the scope of the aforementioned and following principles, all of which fall within the technical scope of the present invention.

[0145] [Examples 1 to 6: First Production Method, Comparative Examples 2 to 4]

[0146] 1. Preparation of layered material particles (MXene)

[0147] First, the following steps are performed in order: (1) preparation of a precursor (MAX), (2) etching of the precursor, (3) cleaning after etching, (4) Li intercalation, and (5) delamination, to obtain MXene particles.

[0148] (1) Preparation of precursor (MAX)

[0149] TiC powder, Ti powder, and Al powder (all manufactured by Kojundo Chemical Laboratory Co., Ltd.) were placed in a ball mill containing zirconia balls at a molar ratio of 2:1:1 and mixed for 24 hours. The resulting mixed powder was calcined at 1350°C for 2 hours under an Ar atmosphere. The resulting calcined body (block-shaped MAX) was crushed with an end mill to a maximum size of 40 μm or less. This yielded Ti3AlC2 particles as a precursor (powdered MAX).

[0150] (2) Etching of the precursor (MAX)

[0151] The Ti 3 AlC 2 particles (powder) prepared by the above method were etched under the following etching conditions to obtain a solid-liquid mixture (slurry) containing solid components derived from the Ti 3 AlC 2 powder.

[0152] (Etching Conditions)

[0153] Precursor: Ti3AlC2 (passing through a 45 μm sieve)

[0154] Etching solution composition: 49% HF 6mL,

[0155] H2O 18mL

[0156] HCl (12M) 36 mL

[0157] Precursor input amount: 3.0g

[0158] Etching container: 100mL wide-mouth bottle (アイボーイ)

[0159] Etching temperature: 35°C

[0160] Etching time: 24h

[0161] Stirrer speed: 400rpm

[0162] (3) Cleaning after etching

[0163] The above slurry was divided into two equal parts and respectively loaded into two 50 mL centrifuge tubes. Then, after centrifugation at 3500G for 5 minutes using a centrifuge, the supernatant was discarded. Then, (i) 35 mL of pure water was added to the remaining precipitate in each centrifuge tube, (ii) it was stirred by hand, (iii) it was centrifuged at 3500G for 5 minutes, and (iv) the supernatant was removed. The steps (i) to (iv) were repeated 10 times. Finally, Ti3C2T was obtained by centrifugation at 3500G for 5 minutes. s -Moisture medium clay.

[0164] (4) Li intercalation

[0165] The Ti3C2T prepared by the above method s - Moisture medium clay was intercalated with LiCl as the Li-containing compound under the following Li intercalation conditions, and stirred at 20° C. to 25° C. for 12 hours. The detailed conditions for Li intercalation are as follows.

[0166] (Li intercalation conditions)

[0167] Ti3 C2T s - Moisture medium clay (MXene after washing): solid content 0.75g

[0168] LiCl: 0.75g

[0169] Intercalation container: 100mL wide-mouth bottle

[0170] Temperature: 20°C or higher and 25°C or lower (room temperature)

[0171] Duration: 12 hours

[0172] Stirrer speed: 800rpm

[0173] (5) Delamination and water cleaning

[0174] The slurry obtained by Li intercalation is put into a 50 mL centrifuge tube, centrifuged at 3500G using a centrifuge, and the supernatant is discarded. Then, (i) 40 mL of pure water is added to the remaining precipitate and stirred on a shaker for 15 minutes, (ii) centrifuged at 3500G, and (iii) the supernatant is recovered as a liquid containing a single layer / few layers of MXene. The operations (i) to (iii) are repeated a total of 4 times to obtain a supernatant containing a single layer / few layers of MXene. Furthermore, the supernatant is centrifuged at 4300G for 2 hours using a centrifuge, and the supernatant is discarded to obtain a MXene clay containing a single layer / few layers of MXene in the form of a remaining precipitate.

[0175] 2. Preparation of MXene-containing dispersion

[0176] A predetermined amount of the MXene clay obtained in step 1 was placed in a 50 mL centrifuge tube, and pure water was added to achieve a MXene concentration of 1.5% by mass. The mixture was then stirred on a shaker for 15 minutes to obtain a slurry containing layered material particles as a dispersion containing layered material particles.

[0177] 3. Preparation of a Dispersion Containing Layered Material Particles Containing Metal Cations

[0178] The above-mentioned slurry containing layered material particles is mixed with a previously prepared 15 mass% LiCl aqueous solution or a 15 mass% NaCl aqueous solution or a 15 mass% KCl aqueous solution and pure water to obtain an aqueous solution containing layered material particles containing metal cations, wherein the layered material particles containing metal cations contain 1.5 mass% MXene and the contents of each metal cation shown in Table 1.

[0179] 4. Fabrication of membranes containing layered material particles containing metal cations

[0180] The dispersion (slurry) containing the layered material particles containing metal cations obtained in 3. is placed in a 25 mL syringe. The syringe is fixed on a spray coater. Next, the atomization pressure in the spray coater is set to 0.5 MPa, the distance between the nozzle tip and the substrate is set to 15 cm, the liquid feed rate is set to 5 mL / s, the scanning speed is set to 150 mm / s, and the hot stage is set to 45°C. Then, the substrate (polyimide film) is coated 15 times using the spray coater. Next, the film is dried at 80°C for 2 hours in a normal pressure oven to obtain a film containing the layered material particles containing metal cations.

[0181] [Examples 7 to 9: Second Manufacturing Method]

[0182] 1. Preparation of layered material particles (MXene)

[0183] Layered material particles were prepared in the same manner as in Examples 1 to 6.

[0184] 2. Preparation of MXene-containing dispersion

[0185] A predetermined amount of the MXene clay obtained in step 1 was placed in a 50 mL centrifuge tube, and pure water was added to achieve a MXene concentration of 1.5% by mass. The mixture was then stirred on a shaker for 15 minutes to obtain a slurry containing layered material particles as a dispersion containing layered material particles.

[0186] 3. Preparation of precursor film (film containing layered material particles)

[0187] The dispersion (slurry) containing MXene obtained in 2. is placed in a 25 mL syringe. The syringe is fixed on a spray coater. Next, the atomization pressure in the spray coater is set to 0.5 MPa, the distance between the nozzle tip and the substrate is set to 15 cm, the liquid delivery volume is set to 5 mL / s, the scanning speed is set to 150 mm / s, and the hot stage is set to 45°C. Then, the substrate (polyimide film) is coated 15 times using the spray coater. Next, a normal pressure oven is used to dry the film at 80°C for 2 hours to obtain a precursor film (a film containing layered material particles).

[0188] 4. Fabrication of membranes containing layered material particles containing metal cations

[0189] First, a 90% by mass aqueous solution of LiCl, a 90% by mass aqueous solution of NaCl, and a 90% by mass aqueous solution of KCl at 25°C was prepared. The precursor film prepared in step 3 was immersed in each of these aqueous solutions for 2 hours, removed, wiped dry, and air-dried for 1 hour to obtain a film (approximately 2 μm thick) containing layered material particles containing metal cations.

[0190] As Comparative Example 1, a film containing layered material particles containing no metal cations (equivalent to a MXene single film, a precursor film) was also produced.

[0191] 〔evaluate〕

[0192] (Determination of Metal Cation Content)

[0193] The film is collected in a container and added with an acid (dilute nitric acid, dilute sulfuric acid, hydrofluoric acid). The content of each metal in the aqueous solution obtained is measured using an ICP (Inductively Coupled Plasma) spectrometer iCAP7400radial manufactured by Thermo Fisher Scientific Co., Ltd. to determine the content of metal cations contained in the film.

[0194] (Implementation of EC12 Test 4)

[0195] 1. Membrane Preparation

[0196] The films containing the metal cation-containing layered material particles (Examples 1 to 9, Comparative Examples 2 to 4) and the MXene film alone (Comparative Example 1) prepared as described above were cut into six pieces of 2 cm×2.5 cm for each level.

[0197] 2. Electrode Preparation

[0198] CR grade Technogel (registered trademark, sheet form) manufactured by Sekisui Chemicals Co., Ltd. was cut into 2 cm squares, and one sheet was attached to each of the membranes cut out in 1. above to obtain electrodes having a gel portion.

[0199] 3. Implementation of the trial

[0200] The test described in 4.2.2.4 of ANSI / AAMI EC12:2000 / (R)2020 (hereinafter referred to as Test 4) was performed according to the following method.

[0201] (1) Two electrodes having a gel portion were prepared, the gel portions were bonded together, and the electrodes were connected to a surface electrode analyzer (Surface Electrode Analysis Meter) manufactured by QC Integrated Solutions, which served as a measurement device, using a separate instrument.

[0202] (2) After charging the capacitor mounted in the measuring device to 200 V, the charged electric power is discharged to the two electrode groups whose gel portions are bonded to each other.

[0203] (3) The potential between electrodes was measured 5 seconds, 15 seconds, 25 seconds, and 35 seconds after the discharge of the capacitor charged to 200 V was completed.

[0204] (4) Repeat the above steps (2) and (3) a total of 4 times.

[0205] 4. Evaluation

[0206] In each of the four consecutive measurements, the inter-electrode potential after 5 seconds was 100 mV or less, and the rate of change in the inter-electrode potential during each 10-second interval from 5 seconds to 15 seconds, from 15 seconds to 25 seconds, and from 25 seconds to 35 seconds was ±10 mV or less, and the impedance at 10 Hz measured after the four consecutive measurements was 3 kΩ or less was evaluated as passing Test 4 (indicated by "G" in Table 1). On the other hand, if at least any one of the above evaluation criteria was not satisfied, it was evaluated as failing Test 4 (indicated by "NG" in Table 1).

[0207] [Table 1]

[0208]

[0209] ※Molar amount of metal cations per 1g of membrane

[0210] The electrodes of Examples 1 to 9, which incorporated a certain amount of metal cations, passed test 4.2.2.4 of ANSI / AAMI EC12:2000 / (R)2020, the standard for disposable electrocardiogram electrodes. It is believed that by introducing the metal cations beforehand, overcharging and the increase in inter-electrode potential were minimized when voltage was applied in the test. Furthermore, by suppressing the increase in inter-electrode potential, the discharge rate was also slowed during discharge, allowing the electrodes to pass test 4.2.2.4 of ANSI / AAMI EC12:2000 / (R)2020. In contrast, Comparative Example 1, which did not incorporate metal cations, and Comparative Examples 2 to 4, which incorporated insufficient amounts of metal cations, failed the test. It is believed that in these comparative examples, when discharging from a capacitor charged to 200 V to the electrode, ions in the gel intercalated into the MXene, causing ion displacement between the electrodes and failing test 4.

[0211] Industrial applicability

[0212] The electrodes disclosed herein may be used for any suitable purpose, and may preferably be used as biological signal sensing electrodes, but are not limited thereto.

[0213] The disclosure of this specification may include the following aspects.

[0214] <1> An electrode comprising a membrane and a conductive gel portion in contact with the membrane, wherein the membrane comprises layered material particles containing metal cations.

[0215] The metal cation-containing layered material particles have a single layer or multiple layers and contain metal cations,

[0216] The layer includes a layer body represented by the following formula, and a modification or terminal T (T is at least one selected from the group consisting of a hydroxyl group, a fluorine atom, a chlorine atom, an oxygen atom, and a hydrogen atom) present on the surface of the layer body,

[0217] M m X n

[0218] (wherein, M is at least one of Group 3, 4, 5, 6, and 7 metals, and contains at least Ti atoms,

[0219] X is a carbon atom, a nitrogen atom or a combination thereof,

[0220] n is 1 or more and 4 or less,

[0221] m is greater than n and less than 5),

[0222] The content of the metal cation is 0.004 mol or more per 1 g of the film.

[0223] <2> The electrode according to <1>, wherein the metal cation includes at least one of a Li cation, a Na cation, and a K cation.

[0224] <3> The electrode according to <1> or <2>, which is a biological signal sensing electrode.

[0225] <4> The electrode according to any one of <1> to <3>, wherein the content of the metal cation is 0.1 mol or less per 1 g of the film.

[0226] <5> A method for manufacturing an electrode, comprising the following steps:

[0227] (a) preparing a layered material particle, the layered material particle comprising a single layer or multiple layers,

[0228] The layer includes a layer body represented by the following formula, and a modification or terminal T (T is at least one selected from the group consisting of a hydroxyl group, a fluorine atom, a chlorine atom, an oxygen atom, and a hydrogen atom) present on the surface of the layer body,

[0229] M m X n

[0230] (wherein, M is at least one of Group 3, 4, 5, 6, and 7 metals, and contains at least Ti atoms,

[0231] X is a carbon atom, a nitrogen atom or a combination thereof,

[0232] n is 1 or more and 4 or less,

[0233] m is greater than n and less than 5);

[0234] (b) mixing the dispersion containing the layered material particles with an aqueous solution containing metal cations to obtain a dispersion containing layered material particles containing metal cations;

[0235] (c) using the dispersion containing the metal cation-containing layered material particles to obtain a film containing the metal cation-containing layered material particles, wherein the content of the metal cation is 0.004 mol or more per 1 g of the film; and

[0236] (d) forming a conductive gel portion on at least one surface of the film.

[0237] <6> The production method according to <5>, wherein the metal cation includes at least one of Li cations, Na cations, and K cations.

[0238] <7> The production method according to <5> or <6>, wherein the content of the metal cation is 0.1 mol or less per 1 g of the film.

[0239] <8> A method for manufacturing an electrode, comprising the following steps:

[0240] (A) preparing a layered material particle comprising a single layer or multiple layers,

[0241] The layer includes a layer body represented by the following formula, and a modification or terminal T (T is at least one selected from the group consisting of a hydroxyl group, a fluorine atom, a chlorine atom, an oxygen atom, and a hydrogen atom) present on the surface of the layer body,

[0242] M m X n

[0243] (wherein, M is at least one of Group 3, 4, 5, 6, and 7 metals, and contains at least Ti atoms,

[0244] X is a carbon atom, a nitrogen atom or a combination thereof,

[0245] n is 1 or more and 4 or less,

[0246] m is greater than n and less than 5);

[0247] (B) using the dispersion containing the layered material particles to obtain a precursor film containing the layered material particles;

[0248] (C) contacting the precursor film with an aqueous solution containing metal cations, thereby obtaining a film containing layered material particles containing metal cations, wherein the content of the metal cations is 0.004 mol or more per 1 g of the film; and

[0249] (D) A conductive gel portion is formed on at least one surface of the film.

[0250] <9> The production method according to <8>, wherein the time for contacting the precursor film with the aqueous solution containing metal cations in (C) is 30 minutes to 24 hours.

[0251] <10> The production method according to <8> or <9>, wherein the metal cation includes at least one of Li cations, Na cations, and K cations.

[0252] <11> The production method according to any one of <8> to <10>, wherein the content of the metal cation is 0.1 mol or less per 1 g of the film.

[0253] This application claims the benefit of priority based on Japanese Patent Application No. 2023-015495, which is hereby incorporated by reference into this specification.

[0254] Description of Reference Numerals

[0255] 1a, 1b layer main body (M m X n layer)

[0256] 3a, 5a, 3b, 5b modification or terminal T

[0257] 7a, 7b MXene layers

[0258] 10, 10a, 10b Layered material particles

Claims

1. An electrode comprising a membrane and a conductive gel portion in contact with the membrane, wherein the membrane comprises layered material particles containing metal cations, The metal cation-containing layered material particles have a single layer or multiple layers and contain metal cations, The layer includes a layer body represented by the following formula, and a modification or terminal T present on the surface of the layer body, wherein T is at least one selected from the group consisting of a hydroxyl group, a fluorine atom, a chlorine atom, an oxygen atom, and a hydrogen atom. M m X n Wherein, M is at least one of Group 3, 4, 5, 6, and 7 metals and contains at least Ti atoms. X is a carbon atom, a nitrogen atom or a combination thereof, n is 1 or more and 4 or less, m is greater than n and less than 5, The content of the metal cation is 0.004 mol or more per 1 g of the film.

2. The electrode according to claim 1, wherein The metal cation includes at least one of Li cation, Na cation, and K cation. The electrode according to claim 1 or 2, which is a biological signal sensing electrode.

4. The electrode according to any one of claims 1 to 3, wherein The content of the metal cation is 0.1 mol or less per 1 g of the film.

5. A method for manufacturing an electrode, comprising the following steps: (a) preparing a layered material particle, the layered material particle comprising a single layer or multiple layers, The layer includes a layer body represented by the following formula, and a modification or terminal T present on the surface of the layer body, wherein T is at least one selected from the group consisting of a hydroxyl group, a fluorine atom, a chlorine atom, an oxygen atom, and a hydrogen atom. M m X n Wherein, M is at least one of Group 3, 4, 5, 6, and 7 metals and contains at least Ti atoms. X is a carbon atom, a nitrogen atom or a combination thereof, n is 1 or more and 4 or less, m is greater than n and less than 5; (b) mixing the dispersion containing the layered material particles with an aqueous solution containing metal cations to obtain a dispersion containing layered material particles containing metal cations; (c) using the dispersion containing the metal cation-containing layered material particles to obtain a film containing the metal cation-containing layered material particles, wherein the content of the metal cation is 0.004 mol or more per 1 g of the film; and (d) forming a conductive gel portion on at least one surface of the film.

6. The manufacturing method according to claim 5, wherein: The metal cation includes at least one of Li cation, Na cation, and K cation.

7. The manufacturing method according to claim 5 or 6, wherein: The content of the metal cation is 0.1 mol or less per 1 g of the film.

8. A method for manufacturing an electrode, comprising the following steps: (A) preparing a layered material particle comprising a single layer or multiple layers, The layer includes a layer body represented by the following formula, and a modification or terminal T present on the surface of the layer body, wherein T is at least one selected from the group consisting of a hydroxyl group, a fluorine atom, a chlorine atom, an oxygen atom, and a hydrogen atom. M m X n Wherein, M is at least one of Group 3, 4, 5, 6, and 7 metals and contains at least Ti atoms. X is a carbon atom, a nitrogen atom or a combination thereof, n is 1 or more and 4 or less, m is greater than n and less than 5; (B) using the dispersion containing the layered material particles to obtain a precursor film containing the layered material particles; (C) contacting the precursor film with an aqueous solution containing metal cations, thereby obtaining a film containing layered material particles containing metal cations, wherein the content of the metal cations is 0.004 mol or more per 1 g of the film; and (D) A conductive gel portion is formed on at least one surface of the film.

9. The manufacturing method according to claim 8, wherein: The time for contacting the precursor film with the aqueous solution containing metal cations in the step (C) is 30 minutes to 24 hours.

10. The manufacturing method according to claim 8 or 9, wherein: The metal cation includes at least one of Li cation, Na cation, and K cation.

11. The production method according to any one of claims 8 to 10, wherein The content of the metal cation is 0.1 mol or less per 1 g of the film.

Images