Electrodes and methods for manufacturing electrodes

Abstract

The present invention provides a low-impedance electrode equipped with a conductive gel. [Solution] An electrode comprising a film containing metal cation-containing layered material particles and a conductive gel portion in contact with the film, wherein the metal cation-containing layered material particles have one or more layers and metal cations, and the layers are of the following formula: M m X n An electrode comprising a layer body represented by the formula (wherein M is at least one group 3, 4, 5, 6, or 7 metal containing at least a Ti atom, X is a carbon atom, a nitrogen atom, or a combination thereof, n is 1 or more and 4 or less, and m is greater than n and 5 or less), and a modification or termination T present on the surface of the layer body (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), wherein the content of the metal cation is 0.004 moles or more per gram of the film.

Description

[Technical Field]

[0001] This disclosure relates to electrodes and methods for manufacturing electrodes. [Background technology]

[0002] In recent years, MXene has attracted attention as a novel material. MXene is a type of so-called two-dimensional material, and as described later, it is a layered material having the form of one or more layers. Generally, MXene has the form of particles of such layered material (hereinafter referred to as "layered material particles," which may include powder, flakes, nanosheets, etc.).

[0003] Currently, various studies are being conducted to explore the application of MXene to a wide range of fields. For example, its application is being considered in applications that require maintaining high conductivity, such as electrodes and electromagnetic shielding (EMI shielding) in electrical devices. For instance, Non-Patent Literature 1 describes that Ti3C2MXene, a two-dimensional material, is clearly different from carbon-based nanomaterials, and that Ti3C2MXene microelectrodes exhibit superior low impedance compared to existing metal microelectrodes, making them suitable for recording neural signals from living organisms, such as the brain. Non-Patent Literature 2 also indicates that MXene may be effective in many applications, ranging from mapping extensive neuromuscular networks in humans to microstimulation of the cortex in small animal models. [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] Driscoll, Nicolette, et al. “Two-dimensional Ti3C2 MXene for high-resolution neural interfaces” ACS nano 12.10 (2018): 10419-10429 [Non-Patent Document 2] Driscoll, Nicolette, et al. “MXene-infused bioelectronic interfaces for multiscale electrophysiology and stimulation” SCIENCE TRANSLATIONAL MEDICINE (2021) [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] For example, in the field of biomedical applications, it is important to minimize the interfacial impedance of electrodes when performing high-resolution sensing. Some electrodes have a conductive gel attached to a conductive film. However, reducing the impedance of electrodes with a conductive gel is difficult, and it is considered that improvements are needed for electrodes containing MXene as described in Non-Patent Documents 1 and 2. This disclosure has been made in view of the above circumstances, and its purpose is to provide a low-impedance electrode with a conductive gel and a method for manufacturing the same. [Means for solving the problem]

[0006] According to one aspect of the present invention, An electrode comprising a film containing metal cation-containing layered material particles and a conductive gel portion in contact with the film, The metal cation-containing layered material particles have one or more layers and metal cations. The aforementioned layer is given by the following formula: M m X n (In the formula, M is at least one group 3, 4, 5, 6, or 7 metal containing at least one Ti atom, X is a carbon atom, a nitrogen atom, or a combination thereof. n is between 1 and 4, m is greater than n and less than or equal to 5. A layer body represented by [formula], and a modification or termination 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, An electrode is provided, wherein the content of the metal cation is 0.004 mol or more per 1 g of the film.

[0007] According to another aspect of the present invention, (a) Layered material particles including one or more layers, wherein the layer is represented by the following formula: M m X n (In the formula, M is at least one metal of Groups 3, 4, 5, 6, and 7, and at least includes a Ti atom, 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 5 or less) Preparing layered material particles including a layer body represented by [formula], and a modification or termination 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, (b) Mixing a dispersion including the layered material particles and an aqueous solution including a metal cation to obtain a dispersion including metal cation-containing layered material particles, (c) Using the dispersion including the metal cation-containing layered material particles to obtain a film including 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 part on at least one surface of the film A method for manufacturing an electrode including the above is provided.

Advantages of the Invention

[0008] According to this disclosure, a film containing particles of a predetermined layered material (also referred to herein as "MXene") contained in the electrode contains a certain amount of metal cations, thereby providing an electrode with a conductive gel that contains MXene and exhibits low impedance. Furthermore, a manufacturing method for easily producing the electrode is also provided. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic cross-sectional view of MXene, which constitutes the film included in the electrode of this embodiment. [Modes for carrying out the invention]

[0010] (Embodiment 1: Electrode) The following describes in detail an electrode in one embodiment of the present invention, but the disclosure is not limited to this embodiment.

[0011] The electrodes in this embodiment are An electrode comprising a film containing metal cation-containing layered material particles and a conductive gel portion in contact with the film, The metal cation-containing layered material particles have one or more layers and metal cations. The aforementioned layer is given by the following formula: M m X n (In the formula, M is at least one group 3, 4, 5, 6, or 7 metal containing at least one Ti atom, X is a carbon atom, a nitrogen atom, or a combination thereof. n is between 1 and 4, m is greater than n and less than or equal to 5. The layer body is represented by and includes a modification or termination 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, The electrode is such that the content of the metal cation is 0.004 mol or more per 1 g of the film. Thereby, an electrode provided with a conductive gel containing MXene and exhibiting low impedance can be realized.

[0012] Hereinafter, a film (which may be referred to as a "metal cation-containing MXene film" or a "conductive film") containing layered material particles (metal cation-containing layered material particles) including one or more layers and metal cations that constitute the electrode of the present embodiment will be described. The above-mentioned layered material can be understood as a layered compound, and is also represented as "M m X n T s ", where s is an arbitrary number, and conventionally, x or z may be used instead of s. Typically, n can be 1, 2, 3, or 4, but is not limited thereto.

[0013] In the above formula of MXene, M may be only Ti, or may have Ti and further have 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, it is more preferable that the element other than Ti is at least one selected from the group consisting of V, Cr, and Mo.

[0014] As MXene, those in which the above formula: M m X n is expressed as follows can be mentioned. Ti2C, Ti2N, (Ti,V)2C, (Ti,Nb)2C, Ti3C2, Ti3N2, Ti3(CN), (Ti,V)3C2, (Ti2Nb)C2, (Ti2Ta)C2, (Ti2Mn)C2, (V2Ti)C2, (Cr2Ti)C2, (Mo2Ti)C2, (W2Ti)C2, Ti4N3, (Ti,Nb)4C3, (Ti2Nb2)C3, (Ti2Ta2)C3, (V2Ti2)C3, (Cr2Ti2)C3, (Mo2Ti2)C3, (W2Ti2)C3

[0015] Typically, in the above formula, M can be titanium or titanium and vanadium, and X can be a carbon atom or a nitrogen atom. For example, the 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).

[0016] In this embodiment, 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 is preferably 8% by mass or less, more preferably 6% by mass or less. However, even if the residual amount of A atoms exceeds 10% by mass, it may not be a problem depending on the application and usage conditions of the electrode.

[0017] In the following, MXene, which constitutes the layered material particles (MXene particles), will be explained using Figure 1. The metal cation-containing layered material particles (MXene particles containing metal cations) according to this embodiment have a framework that is almost the same as that of the layered material particles (MXene particles). Figure 1 illustrates the structure corresponding to the framework of the MXene particles containing metal cations, and the metal cations are not shown in Figure 1.

[0018] The layered material particles (MXene particles) according to this embodiment are aggregates containing multiple single-layer MXene 10a (monolayer MXene) as schematically illustrated in Figure 1(a) (however, as mentioned above, metal cations are not shown). More specifically, MXene 10a is M m X n The layer body (M) represented by m X n The MXene layer 7a has a layer 1a and modifications or terminations T3a, 5a 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 "M m X n T s It can also be expressed as , where s is any number.

[0019] In this embodiment, the MXene particles may consist of one or more layers. As an example of multilayer MXene (multilayer MXene), two layers of MXene 10b are schematically shown in Figure 1(b), but the embodiment is not limited to these examples. 1b, 3b, 5b, and 7b in Figure 1(b) are the same as 1a, 3a, 5a, and 7a in Figure 1(a) described above. Two adjacent MXene layers of multilayer MXene (e.g., 7a and 7b) do not necessarily have to be completely separated, but may be partially in contact. The MXene 10a may be a single layer formed by the individual separation of the multilayer MXene 10b, while unseparated multilayer MXene 10b may remain, resulting in a mixture of single-layer MXene 10a and multilayer MXene 10b. Even when multilayer MXene is included, it is preferable that the multilayer MXene is obtained through a delamination process and has a small number of layers. "Small number of layers" means, for example, that the number of MXene layers is 10 or less. Hereafter, this "multilayer MXene with a small number of layers" may be referred to as "low-layer MXene." The thickness in the stacking direction of low-layer MXene may be 15 nm or less, and may even be 10 nm or less. Also, single-layer MXene and low-layer MXene may be collectively referred to as "single-layer low-layer MXene."

[0020] The above MXene may mostly consist of single-layer or multi-layer MXene. Having a large proportion of single-layer or multi-layer MXene allows for a larger specific surface area than multi-layer MXene, resulting in suppressed degradation of conductivity over time when the laminate is used in applications requiring conductivity. For example, single-layer or multi-layer MXene, with 10 or fewer layers and a thickness of 15 nm or less, preferably 10 nm or less, may constitute 80% or more by volume of the total MXene, or even 90% or more by volume, or even 95% or more by volume. Furthermore, the volume of single-layer MXene may be greater than the volume of multi-layer MXene. Since the true density of these MXene does not vary significantly depending on their form, it can also be said that the mass of single-layer MXene is greater than the mass of multi-layer MXene. In these relationships, the specific surface area of ​​MXene can be increased, and degradation of conductivity over time can be suppressed when used in applications requiring conductivity. For example, a film may be formed using only single-layer MXene.

[0021] Although not limited to this embodiment, the thickness of each MXene layer (corresponding to the MXene layers 7a and 7b described above) can be, for example, 1 nm or more and 30 μm or less, for example, 1 nm or more and 5 nm or less, or even 1 nm or more and 3 nm or less (this mainly depends on the number of M atomic layers contained in each layer). For each laminate of the multilayer MXene that may be included, the interlayer distance (or void dimension, shown as Δd in Figure 1(b)) is, for example, 0.8 nm or more and 10 nm or less, particularly 0.8 nm or more and 5 nm or less, and more particularly about 1 nm, and the total number of layers can be 2 or more and 20,000 or less.

[0022] Metal cation-containing layered material particles, as the name suggests, contain metal cations. While the type of metal cation is not limited, alkali metal cations are preferred, considering their ease of insertion between layers of the layered material particles, and it is more preferable that the particles contain at least one of Li cations, Na cations, and K cations. It is particularly preferable that the metal cation is at least one of Li cations, Na cations, and K cations.

[0023] The content of the metal cations is 0.004 moles (0.004 moles / g) or more per gram of the film containing the metal cation-containing layered material particles (metal cation-containing MXene film, conductive film). It is believed that many metal cations are intercalated between the layers of MXene. The presence of a certain or greater abundance of metal cations in the precursor film, the MXene film, can prevent the diffusion of ions from an ion-containing medium, such as a conductive gel. This disclosure is not bound by any theory, but it is believed that setting the metal cation content above a certain level will produce the following effects. That is, when discharge is made from a capacitor to an electrode, conventionally, it is thought that ions in the conductive gel at the electrode intercalate into MXene, creating an ion imbalance between the electrodes and increasing the inter-electrode potential. However, by setting the metal cation content to 0.004 moles / g or more, and by pre-containing an abundance of ions in MXene, it is believed that further intercalation of ions due to discharge from the capacitor is suppressed, the ion imbalance between the electrodes is suppressed, and the rise in the inter-electrode potential can be suppressed. The content of the metal cation is preferably 0.006 moles or more per gram of film containing the metal cation-containing layered material particles. While a higher content of the metal cation is preferable, from the viewpoint of ease of manufacture, it can be 0.1 moles or less (0.1 moles / g or less) per gram of film containing the metal cation-containing layered material particles. The content of the metal cation can further be 0.05 moles / g or less.

[0024] The electrode according to this embodiment includes at least the film and the conductive gel portion. The electrode may be formed from only the conductive film and the conductive gel portion, or it may include the conductive film and the conductive gel portion and, for example, a substrate.

[0025] The conductive gel portion of the electrode in this embodiment may be composed of a gel material in which a solvent such as water or a humectant, a conductive material, etc., is held within a three-dimensional polymer matrix. For example, Technogel (registered trademark) of Sekisui Chemical Co., Ltd. may be used as the gel material.

[0026] The electrodes in this embodiment range from solid to flexible and soft.

[0027] If the electrode of this 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 is formed of a conductive material. Examples of conductive materials include at least one of the following materials: metallic materials such as gold, silver, copper, platinum, nickel, titanium, tin, iron, zinc, magnesium, aluminum, tungsten, and molybdenum, and conductive polymers. The substrate may have a conductive film, such as a metal film, on the contact surface with the conductive film according to this embodiment, which is different from the conductive film according to this embodiment. Alternatively, the substrate may be formed of an organic material. Examples of the organic material include flexible organic materials, such as thermoplastic polyurethane elastomer (TPU), PET film, and polyimide film.

[0028] (Applications of electrodes) The electrodes of this embodiment can be used for any suitable application. While not particularly limited, they may include, for example, biosignal sensing electrodes, capacitor electrodes, battery electrodes, and sensor electrodes. Details of these applications will be described below.

[0029] Biosignal sensing electrodes are electrodes used to acquire biological signals. Biosignal sensing electrodes may, but are not limited to, electrodes used to measure ECG (electrocardiogram), EEG (electroencephalogram), EMG (electromyogram), and EIT (electrical impedance tomography).

[0030] A capacitor can be an electrochemical capacitor. An electrochemical capacitor is a capacitor that utilizes the capacitance that arises from a physicochemical reaction between electrodes (electrode active material) and ions in an electrolyte (electrolyte ions), and can be used as a device for storing electrical energy (energy storage device). A battery can be a chemical battery that can be repeatedly charged and discharged. A battery can be, for example, a lithium-ion battery, a magnesium-ion battery, a lithium-sulfur battery, a sodium-ion battery, etc., but is not limited to these.

[0031] Sensor electrodes are electrodes used to detect a target substance, state, abnormality, etc. Sensors may include, but are not limited to, gas sensors or biosensors (chemical sensors that utilize molecular recognition mechanisms of biological origin).

[0032] The electrodes of this embodiment are preferably used as biosignal sensing electrodes. As described above, electrodes having a film composed of MXene rich in metal cations and a conductive gel portion are thought to exhibit low impedance and small ion imbalance between electrodes when discharged from a capacitor, for example, when used as disposable electrocardiogram electrodes. As a result, it is thought that they will have high sensitivity when used as biosignal sensing electrodes.

[0033] (Embodiment 3: Method for manufacturing electrodes) The method for manufacturing electrodes according to this embodiment will be described in detail, but this disclosure is not limited to such embodiments.

[0034] The manufacturing method (first manufacturing method) for one electrode of this embodiment is: (a) Layered material particles comprising one or more layers, The aforementioned layer is given by the following formula: M m X n (In the formula, M is at least one group 3, 4, 5, 6, or 7 metal containing at least one Ti atom, X is a carbon atom, a nitrogen atom, or a combination thereof. n is between 1 and 4, m is greater than n and less than or equal to 5. To prepare layered material particles comprising a layer body represented by and a modification or termination T (where T is at least one selected from the group consisting of hydroxyl groups, fluorine atoms, chlorine atoms, oxygen atoms, and hydrogen atoms) present on the surface of the layer body, (b) Mixing a dispersion containing the layered material particles with an aqueous solution containing metal cations to obtain a dispersion containing metal cation-containing layered material particles. (c) Using a dispersion containing the metal cation-containing layered material particles, obtain a film containing metal cation-containing layered material particles in which the metal cation content is 0.004 moles or more per gram of film, and (d) Forming a conductive gel portion on at least one surface of the film. This is a method for manufacturing electrodes, which includes [the specified element].

[0035] Another method for manufacturing the electrode of this embodiment (second manufacturing method) is: (A) Layered material particles comprising one or more layers, The aforementioned layer is given by the following formula: M m X n (In the formula, M is at least one group 3, 4, 5, 6, or 7 metal containing at least one Ti atom, X is a carbon atom, a nitrogen atom, or a combination thereof. n is between 1 and 4, m is greater than n and less than or equal to 5. To prepare layered material particles comprising a layer body represented by and a modification or termination T (where T is at least one selected from the group consisting of hydroxyl groups, fluorine atoms, chlorine atoms, oxygen atoms, and hydrogen atoms) present on the surface of the layer body, (B) Obtain a precursor film containing layered material particles using a dispersion containing the layered material particles. (C) Contacting the precursor film with an aqueous solution containing metal cations to obtain a film containing metal cation-containing layered material particles in which the metal cation content is 0.004 moles or more per gram of film, and (D) Forming a conductive gel portion on at least one surface of the film. This is a method for manufacturing electrodes, which includes [the specified element].

[0036] The following details each step of the first and second manufacturing methods. Steps (a) and (A), and steps (d) and (D), which are common to both manufacturing methods, will be explained together.

[0037] Process (a) and Process (A) First, a predetermined precursor is prepared. In this embodiment, the predetermined precursor that can be used is the MAX phase, which is a precursor of MXene. The following formula: M m AX n (In the formula, M is at least one group 3, 4, 5, 6, or 7 metal, which includes Ti, X is a carbon atom, a nitrogen atom, or a combination thereof. A is at least one element from groups 12, 13, 14, 15, or 16. n is between 1 and 4, m is greater than n and less than or equal to 5. It is represented as follows.

[0038] The above M, X, n, and m are as described in MXene. A is at least one element from groups 12, 13, 14, 15, or 16, usually a group A element, typically from groups IIIA and IVA, and more specifically may include at least one selected from the group consisting of Al, Ga, In, Tl, Si, Ge, Sn, Pb, P, As, S, and Cd, preferably Al.

[0039] The MAX phase is M m X n The MAX phase has a crystal structure in which a layer composed of A atoms is located between two layers represented by (each X may have a crystal lattice located within an octahedral array of M). Typically, in the case of m=n+1, one layer of X atoms is placed between each of the n+1 layers of M atoms (these together are called "M"). m X n It has, but is not limited to, a repeating unit in which a layer of A atoms ("A atomic layer") is placed as the layer following the n+1th M atom layer (also called a "layer").

[0040] The MAX phase described above can be manufactured by known methods. For example, TiC powder, Ti powder, and Al powder can be mixed in a ball mill, and the resulting mixed powder can be calcined in an Ar atmosphere to obtain a calcined body (block-shaped MAX phase). The calcined body can then be crushed with an end mill to obtain powdered MAX phase for the next process.

[0041] A atoms (and possibly some M atoms) are selectively etched (removed and possibly separated) from the MAX phase, thereby removing the A atomic layer (and possibly some M atoms) and exposing the M m X n The surface of the layer is modified by hydroxyl groups, fluorine atoms, chlorine atoms, oxygen atoms, and hydrogen atoms, etc., present in the etching solution (usually an aqueous solution of fluorinated acid, but not limited to this), thereby terminating the surface.

[0042] The above etching is F -The process may be carried out using an etching solution containing the above, for example, a method using a mixture of lithium fluoride and hydrochloric acid, or a method using hydrofluoric acid. The etching solution may contain a metal compound containing a monovalent metal ion, and the intercalation treatment of the monovalent metal ion may be performed simultaneously with the etching. Examples of metal compounds containing monovalent metal ions include those used in the intercalation treatment described below. 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 even more preferably 0.1% by mass or more. On the other hand, from the viewpoint of dispersibility in the solution, the content of the metal compound containing a monovalent metal ion in the etching solution is preferably 10% by mass or less, and more preferably 1% by mass or less.

[0043] After etching as described above, appropriate post-treatment (e.g., ultrasonic treatment, handshake, or automatic shaker) may be used to promote layer separation of MXene (delamination, separation of multilayer MXene into single-layer MXene). However, since ultrasonic treatment can cause the MXene to break due to excessive shear force, if it is desired to obtain MXene with a larger aspect ratio in a two-dimensional shape (preferably single-layer MXene), it is preferable to apply an appropriate shear force using a handshake or automatic shaker.

[0044] To separate the layers of the aforementioned MXene, the following intercalation and delamination processes may be performed.

[0045] (Intercalation process) For example, an intercalation treatment of monovalent metal ions can be performed, which includes a step of mixing the etched product obtained by the etching treatment with a metal compound containing monovalent metal ions. Examples of monovalent metal ions constituting the metal compound containing monovalent metal ions include alkali metal ions such as Li ions, Na ions, and K ions, as well as copper ions, silver ions, and gold ions. Examples of the metal compound containing monovalent metal ions include ionic compounds in which the above metal ions are bonded to cations. Examples of the above metal ions include iodides, phosphates, sulfide salts including sulfates, nitrates, acetates, and carboxylates. As mentioned above, Li ions are preferred as the monovalent metal ions, and metal compounds containing Li ions are preferred as the metal compound containing monovalent metal ions, ionic compounds of Li ions are more preferred, and one or more of Li ion iodides, phosphates, and sulfide salts are even more preferred. If Li ions are used as the metal ions, it is thought that monolayer formation is easier because the water hydrated with the Li ions has the most negative dielectric constant.

[0046] The content of the metal compound containing monovalent metal ions in the intercalation treatment formulation for monovalent metal ions is preferably 0.001% by mass or more. More preferably, this content is 0.01% by mass or more, and even more preferably 0.1% by mass or more. On the other hand, from the viewpoint of dispersibility in solution, the content of the metal compound containing monovalent metal ions is preferably 10% by mass or less, and more preferably 1% by mass or less.

[0047] (Delamination) One method is to perform delamination using the intercalation-treated material obtained by intercalation. For example, delamination may include a step of centrifuging the intercalation-treated material, discarding the supernatant, and washing the remaining precipitate with water. The conditions for the delamination treatment are not particularly limited. The dispersion medium used for delamination is also not particularly limited, and for example, one or more of a polar organic dispersion medium and an aqueous dispersion medium may be used. One or more of the polar organic dispersion medium and the aqueous dispersion medium may be added and stirred, and the supernatant liquid may be recovered by centrifugation, and this process may be repeated one or more times, preferably two or more times and no more than 10 times, to obtain a supernatant liquid containing a single layer or a small layer of MXene as the delamination-treated material. Alternatively, this supernatant liquid may be centrifuged, and the supernatant liquid after centrifugation may be discarded to obtain a single layer or a small layer of MXene-containing clay as the delamination-treated material.

[0048] ·Process (b) In the first manufacturing method, a dispersion containing the layered material particles is mixed with an aqueous solution containing metal cations to obtain a dispersion containing metal cation-containing layered material particles.

[0049] The dispersion containing the layered material particles can be obtained, for example, by stirring and mixing the single-layer or thin-layer MXene-containing clay obtained by the delamination with an aqueous dispersion medium such as pure water, as a slurry containing the layered material particles.

[0050] The type of metal cation contained in the aqueous solution containing the metal cation is not limited, but alkali metal cations are preferred, and it is more preferable that the aqueous solution contains at least one of Li cations, Na cations, and K cations, considering that they are easily inserted between the layers of the layered material particles. It is particularly preferable that the metal cation is at least one of Li cations, Na cations, and K cations. The concentration of the metal cation in the aqueous solution containing the metal cation is not particularly limited, as long as the amount of metal cation per gram of the final film is 0.004 moles or more. From the viewpoint of mixing with a dispersion containing the layered material particles and easily intercalating the metal cation between the layers of the layered material particles, it is preferable to use an aqueous solution containing 10% to 30% by mass of a metal cation, such as chloride, fluoride, bromide, iodide, sulfate, nitrate, or phosphate.

[0051] The method for mixing the dispersion containing the layered material particles with the aqueous solution containing the metal cation is not particularly limited and can be done by known stirring methods. The temperature of the liquids during mixing is also not particularly limited and can be room temperature.

[0052] ·Process (c) In the first manufacturing method, a film containing metal cation-containing layered material particles is obtained using a dispersion containing the metal cation-containing layered material particles. For the formation of the film, a dispersion of metal cation-containing MXene can be used, such as a metal cation-containing MXene slurry obtained by diluting clay containing the metal cation-containing MXene with a medium. The dispersion may also be a suspension. The method for forming a film using a dispersion of metal cation-containing MXene is not particularly limited. The dispersion of metal cation-containing MXene may be applied to a substrate as is, or after being appropriately adjusted (for example, by diluting with a medium or adding a binder). Examples of application methods include spray coating using a nozzle such as a one-fluid nozzle, two-fluid nozzle, or airbrush (using a spray coater), slit coating using a table coater, comma coater, or bar coater, screen printing, metal mask printing, spin coating, dip coating, and drop coating. Examples of the medium include aqueous mediums and organic mediums. The media liquid constituting the dispersion of the metal cation-containing MXene described above is typically water, but may also contain other liquid substances in relatively small amounts (for example, 30% by mass or less, preferably 20% by mass or less, on a total basis) in addition to water. Examples of the organic media liquid include N-methylpyrrolidone, N-methylformamide, N,N-dimethylformamide, ethanol, methanol, dimethyl sulfoxide, ethylene glycol, and acetic acid.

[0053] When forming using a spray coater, for example, a metal cation-containing MXene slurry is applied to a substrate such as PET or polyimide in one or more passes, with the atomization pressure set to 0.1 MPa or more and 0.5 MPa or less, the distance between the nozzle tip and the substrate to 10 cm or more and 25 cm or less, the liquid flow rate to 0.1 mL / s or more and 10 mL / s or less, the sweep speed to 1 mm / s or more and 30 mm / s or less, and the stage heater set to 30°C or more and 60°C or less, to form a film (electrode) before drying.

[0054] In addition to preparing a film by spraying as described above, a film may also be prepared by suction filtration of a metal cation-containing MXene slurry. More specifically, the concentration of the metal cation-containing MXene slurry can be appropriately adjusted (diluted with an aqueous medium, if necessary), and the slurry can be suction filtered through a filter installed in a Nutsch or the like (which may constitute a predetermined component together with the metal cation-containing MXene film, or may ultimately be separated from the metal cation-containing MXene film) to remove at least partially the aqueous medium, thereby forming a film on the filter. The filter is not particularly limited, but a membrane filter or the like may be used.

[0055] The aforementioned substrate may or may not be present. If a substrate is present, the material constituting the substrate is not particularly limited and can consist of any suitable material. The substrate may be, for example, a resin film, metal foil, printed circuit board, mounted electronic component, metal pin, metal wiring, metal wire, etc. For example, a substrate made of a metal material, resin, etc., suitable for biosignal sensing electrodes can be appropriately used. A metal cation-containing MXene film can be formed on the substrate by coating it onto any suitable substrate (which may constitute a predetermined component together with the metal cation-containing MXene film, or may ultimately be separated from the metal cation-containing MXene film).

[0056] Drying may be carried out under mild conditions such as natural drying (typically placed in an air atmosphere at room temperature and pressure) or air drying (blowing air), or under relatively active conditions such as hot air drying (blowing heated air), heat drying, and / or vacuum drying. In this embodiment, "drying" means removing any media liquid that may be present in the film. The drying may be carried out, for example, at a temperature of 400°C or less using an atmospheric pressure oven or a vacuum oven. For example, drying may be carried out at a temperature of 30°C to 200°C for 30 minutes to 24 hours.

[0057] The formation and drying of the metal cation-containing MXene film may be repeated as needed until the desired film thickness is obtained. For example, the spraying and drying combination may be repeated multiple times. The metal cation-containing MXene film may or may not contain any residual liquid components derived from the liquid medium of the slurry.

[0058] ·Process (B) In the second manufacturing method, a precursor film containing the layered material particles is obtained using a dispersion containing the layered material particles. For the formation of the precursor film, a dispersion of layered material particles (MXene particles), such as an MXene slurry obtained by diluting the single-layer or thin-layer MXene-containing clay with a medium, can be used. The dispersion may also be a suspension. The method for forming the precursor film using the dispersion of MXene particles is not particularly limited. The dispersion of MXene particles may be applied to a substrate as is, or after being appropriately adjusted (for example, by diluting with a medium or adding a binder). Examples of application methods include spray coating using a nozzle such as a one-fluid nozzle, two-fluid nozzle, or airbrush (using a spray coater), slit coating using a table coater, comma coater, or bar coater, screen printing, metal mask printing, spin coating, dip coating, and drop coating. Examples of the medium include aqueous mediums and organic mediums. The media liquid constituting the dispersion of MXene particles is typically water, but may also contain other liquid substances in relatively small amounts (for example, 30% by mass or less, preferably 20% by mass or less, on a total basis) in addition to water. Examples of the organic media liquid include N-methylpyrrolidone, N-methylformamide, N,N-dimethylformamide, ethanol, methanol, dimethyl sulfoxide, ethylene glycol, and acetic acid.

[0059] When forming using a spray coater, for example, an MXene slurry is applied to a substrate such as PET or polyimide in one or more coats, with the atomization pressure set to 0.1 MPa or more and 0.5 MPa or less, the distance between the nozzle tip and the substrate to 10 cm or more and 25 cm or less, the liquid flow rate to 0.1 mL / s or more and 10 mL / s or less, the sweep speed to 1 mm / s or more and 30 mm / s or less, and the stage heater set to 30°C or more and 60°C or less, to form a film before drying.

[0060] In addition to preparing the precursor film by the spray method described above, the precursor film may also be prepared by suction filtration of the supernatant liquid containing MXene particles obtained from the slurry or delamination described above. More specifically, as a dispersion of MXene particles, for example, the supernatant liquid containing MXene particles can be appropriately adjusted (for example, diluted with an aqueous medium) and suction filtered through a filter installed in a Nutsch or the like (which may constitute a predetermined component together with the precursor film, or may be ultimately separated from the precursor film) to remove at least partially the aqueous medium liquid, thereby forming a precursor film on the filter. The filter is not particularly limited, but a membrane filter or the like can be used. By suction filtration as described above, the precursor film can be prepared without using the binder or the like. Using the MXene particles of this embodiment, the precursor film can be prepared in this way without using the binder or the like.

[0061] The aforementioned substrate may or may not be present. If a substrate is present, the material constituting the substrate is not particularly limited and can consist of any suitable material. The substrate may be, for example, a resin film, metal foil, printed circuit board, mounted electronic component, metal pin, metal wiring, or metal wire. For example, a substrate made of a metal material, resin, etc., suitable for biosignal sensing electrodes can be appropriately used. The precursor film can be formed on the substrate by coating it onto any suitable substrate (which may constitute a predetermined component together with the precursor film, or may be ultimately separated from the precursor film).

[0062] Drying may be carried out under mild conditions such as natural drying (typically placed in an air atmosphere at room temperature and pressure) or air drying (by blowing air), or under relatively active conditions such as hot air drying (by blowing heated air), heat drying, and / or vacuum drying. In this embodiment, "drying" means removing any media liquid that may be present in the precursor film. The drying may be carried out, for example, at a temperature of 400°C or less using an atmospheric pressure oven or a vacuum oven. For example, drying may be carried out at a temperature of 30°C to 200°C for 30 minutes to 24 hours.

[0063] The formation and drying of the precursor film may be repeated as needed until the desired precursor film thickness is obtained. For example, the combination of spraying and drying may be repeated multiple times. According to the above suction filtration, a precursor film can be formed without containing a binder. The precursor film may or may not contain any residual liquid components derived from the liquid medium of the slurry.

[0064] ·Process (C) In the second manufacturing method, the precursor film is brought into contact with an aqueous solution containing metal cations to obtain a film containing metal cation-containing layered material particles (metal cation-containing MXene film).

[0065] The type of metal cation contained in the aqueous solution containing the metal cation is not limited, but alkali metal cations are preferred, and it is more preferable that the aqueous solution contains at least one of Li cations, Na cations, and K cations, considering that they are easily inserted between the layers of the layered material particles. It is particularly preferable that the metal cation is at least one of Li cations, Na cations, and K cations. The concentration of the metal cation in the aqueous solution containing the metal cation is not particularly limited, as long as there are 0.004 moles or more of metal cation per gram of the final film obtained. From the viewpoint of contacting the precursor film and easily intercalating the metal cation between the layers of the layered material particles, it is preferable to use an aqueous solution containing 50 to 95% by mass of the saturated solubility amount of each metal cation, such as chlorides, fluorides, bromides, iodides, sulfates, nitrates, phosphates, etc., at 25°C.

[0066] The temperature of the aqueous solution containing the metal cation when it is brought into contact with the precursor film may be room temperature. The method of bringing the precursor film into contact with the aqueous solution containing the metal cation is not particularly limited, and examples include immersing the precursor film in the aqueous solution containing the metal cation, or spray coating using a nozzle to bring at least one side of the precursor film into contact with the entire or partial surface. The contact time (immersion time in the case of immersion) can be, for example, 30 minutes to 24 hours.

[0067] • Process (d) and process (D) A conductive gel portion is formed on at least one surface of the obtained metal cation-containing MXene film. The conductive gel included in the aforementioned electrode can be used as the conductive gel. The conductive gel is formed by coating, attaching, or otherwise applying it to at least one surface of the metal cation-containing MXene film. The area where the conductive gel portion is formed on at least one surface of the film may be the entire surface or only a part of it, as needed.

[0068] The electrode in one embodiment of this disclosure has been described in detail above, but this disclosure is subject to various modifications. It should be noted that the electrode of this disclosure may be manufactured by a method different from the manufacturing method in the embodiment described above. [Examples]

[0069] The present invention will be described in more detail below with reference to examples. The present invention is not limited by the following examples, and can be implemented with appropriate modifications within the scope that is consistent with the spirit described above and below, and all such modifications are included within the technical scope of the present invention.

[0070] [Examples 1-6: First manufacturing method, Comparative Examples 2-4] 1. Preparation of layered material particles (MXene) MXene particles were first obtained by sequentially performing the following steps, as detailed below: (1) preparation of the precursor (MAX), (2) etching of the precursor, (3) washing after etching, (4) Li intercalation, and (5) delamination.

[0071] (1) Preparation of the precursor (MAX) TiC powder, Ti powder, and Al powder (all manufactured by Kojun Chemical Laboratory Co., Ltd.) were placed in a ball mill containing zirconia balls in 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 then pulverized with an end mill to a maximum size of 40 μm or less. This yielded Ti3AlC2 particles as a precursor (powdered MAX).

[0072] (2) Etching of the precursor (MAX) Using the Ti3AlC2 particles (powder) prepared by the above method, etching was performed under the following etching conditions to obtain a solid-liquid mixture (slurry) containing solid components derived from the Ti3AlC2 powder. (Etching conditions) • Precursor: Ti3AlC2 (passed through a sieve with a mesh size of 45 μm) • Etching solution composition: 49% HF 6 mL, H2O 18mL HCl (12M) 36mL • Amount of precursor added: 3.0g • Etching container: 100mL iBoy Etching temperature: 35℃ Etching time: 24 hours • Stirrer rotation speed: 400 rpm

[0073] (3) Cleaning after etching The slurry was divided equally into two portions and placed into two 50 mL centrifuge tubes. The mixture was then centrifuged at 3500 G for 5 minutes, and the supernatant was discarded. Next, (i) 35 mL of pure water was added to the remaining precipitate in each centrifuge tube, (ii) the mixture was stirred by handshaking, (iii) centrifuged at 3500 G for 5 minutes, and (iv) the supernatant was removed. Steps (i) through (iv) were repeated 10 times. Finally, the mixture was centrifuged at 3500 G for 5 minutes to obtain Ti3C2T. s - A water-based clay was obtained.

[0074] (4) Li intercalation Ti3C2T prepared by the above method s -Li intercalation was performed on a water-based clay medium using LiCl as the Li-containing compound, stirring at 20°C to 25°C for 12 hours, according to the Li intercalation conditions described below. The detailed conditions for Li intercalation are as follows. (Conditions for Li intercalation) ·Ti3C2T s - Moisture-based clay (MXene after washing): Solid content 0.75g LiCl: 0.75g Intercalation container: 100mL iBoy ·Temperature: 20℃ or higher and 25℃ or lower (room temperature) ·Time: 12h • Stirrer rotation speed: 800 rpm

[0075] (5) Delamination and washing The slurry obtained by Li intercalation was placed in a 50 mL centrifuge tube and centrifuged at 3500 G using a centrifuge, after which the supernatant was discarded. Next, (i) 40 mL of pure water was added to the remaining precipitate and stirred in a shaker for 15 minutes, (ii) then centrifuged at 3500 G, and (iii) the supernatant was collected as a monolayer / sparse-layer MXene-containing liquid. This procedure (i) to (iii) was repeated a total of four times to obtain a monolayer / sparse-layer MXene-containing supernatant. Furthermore, this supernatant was centrifuged at 4300 G for 2 hours using a centrifuge, after which the supernatant was discarded, and the remaining precipitate was obtained as MXene clay containing a monolayer / sparse layer of MXene.

[0076] 2. Preparation of a dispersion containing MXene A predetermined amount of MXene clay obtained in step 1 was placed in a 50 mL centrifuge tube, and pure water was added to adjust the MXene concentration to 1.5% by mass. The mixture was then stirred in a shaker for 15 minutes to obtain a slurry containing layered material particles as a dispersion containing layered material particles.

[0077] 3. Preparation of a dispersion containing metal cation-containing layered material particles. A slurry containing the above-mentioned layered material particles was mixed with a pre-prepared 15% by mass LiCl aqueous solution, a 15% by mass NaCl aqueous solution, or a 15% by mass KCl aqueous solution, and pure water to obtain an aqueous solution containing metal cation-containing layered material particles, which contained 1.5% by mass MXene and the metal cations in the amounts shown in Table 1.

[0078] 4. Fabrication of a film containing metal cation-containing layered material particles The dispersion (slurry) containing the metal cation-containing layered material particles obtained in step 3 above was placed in a 25 mL syringe. The syringe was then set in a spray coater. Next, the atomization pressure in the spray coater was set to 0.5 MPa, the distance between the nozzle tip and the substrate to 15 cm, the liquid flow rate to 5 mL / s, the sweep speed to 150 mm / s, and the stage heater to 45°C. Then, the spray coater was used to coat the substrate (polyimide film) 15 times. Next, the film containing the metal cation-containing layered material particles was dried in an atmospheric pressure oven at 80°C for 2 hours.

[0079] [Examples 7-9: Second Manufacturing Method] 1. Preparation of layered material particles (MXene) Layered material particles were prepared in the same manner as in Examples 1 to 6 described above.

[0080] 2. Preparation of a dispersion containing MXene A predetermined amount of MXene clay obtained in step 1 was placed in a 50 mL centrifuge tube, and pure water was added to adjust the MXene concentration to 1.5% by mass. The mixture was then stirred in a shaker for 15 minutes to obtain a slurry containing layered material particles as a dispersion containing layered material particles.

[0081] 3. Preparation of precursor film (film containing layered material particles) The dispersion (slurry) containing MXene obtained in step 2 above was placed in a 25 mL syringe. The syringe was then set in a spray coater. Next, the atomization pressure in the spray coater was set to 0.5 MPa, the distance between the nozzle tip and the substrate to 15 cm, the liquid flow rate to 5 mL / s, the sweep speed to 150 mm / s, and the stage heater to 45°C. Then, the spray coater was used to coat the substrate (polyimide film) 15 times. Next, the film was dried in an atmospheric pressure oven at 80°C for 2 hours to obtain a precursor film (a film containing layered material particles).

[0082] 4. Fabrication of a film containing metal cation-containing layered material particles First, 90% by mass aqueous solutions of LiCl, NaCl, and KCl were prepared at their respective saturated dissolution amounts at 25°C. The precursor film prepared in step 3 was immersed in each of the above aqueous solutions for 2 hours, removed, wiped dry, and dried in the air for 1 hour to obtain a film containing metal cation-containing layered material particles (film thickness approximately 2 μm).

[0083] As Comparative Example 1, a film containing layered material particles that do not contain metal cations (corresponding to a single MXene film and a precursor film) was also prepared.

[0084] 〔evaluation〕 (Measurement of metal cation content) The content of metal cations contained in the aforementioned film was determined by taking a sample of the film into a container, adding an acid (dilute nitric acid, dilute sulfuric acid, hydrofluoric acid), dissolving it in an UltraWAVE ECR microwave sample decomposition device manufactured by Milestone General Co., Ltd., and then measuring the content of each metal in the resulting aqueous solution using an iCAP7400 radial ICP (Inductively Coupled Plasma) emission spectrometer manufactured by Thermo Fisher Scientific Co., Ltd.

[0085] (EC12 Test 4 execution) 1. Membrane preparation As described above, the films containing metal cation-containing layered material particles (Examples 1-9, Comparative Examples 2-4) and the MXene-only film (Comparative Example 1) were cut into six 2cm x 2.5cm pieces per level. 2. Preparation of electrodes CR Grade Technogel (registered trademark, in sheet form), manufactured by Sekisui Chemical Co., Ltd., was cut into 2 cm squares, and one sheet was attached to each of the films cut out in step 1 above to obtain an electrode having a gel portion. 3. Conducting the test The test described in ANSI / AAMI EC12:2000 / (R)2020, section 4.2.2.4 (hereinafter referred to as Test 4), was performed using the following method. (1) Two electrodes, each having a gel portion, were prepared and the gel portions were bonded together. These electrodes were then connected to a Surface Electrode Analysis Meter manufactured by QC Integrated Solutions, which was a measuring device, using a separately provided instrument. (2) The capacitor incorporated in the measuring device was charged to 200V, and then the charged electricity was discharged onto the two electrodes, which were bonded together with their gel portions attached. (3) The inter-electrode potential was measured 5 seconds, 15 seconds, 25 seconds, and 35 seconds after the discharge of the capacitor charged to 200V was completed. (4) The above steps (2) and (3) were performed a total of four times in a row. 4. Evaluation In all four consecutive measurements described above, if the electrode potential after 5 seconds was 100mV or less, and the rate of change of electrode potential during each 10-second period from 5 seconds to 15 seconds, from 15 seconds to 25 seconds, and from 25 seconds to 35 seconds was ±10mV or less, and furthermore, if the impedance at 10Hz measured after all four consecutive measurements was 3kΩ or less, then Test 4 was cleared (indicated as "G" in Table 1). On the other hand, if at least one of the above evaluation criteria was not met, then Test 4 was not cleared (indicated as "NG" in Table 1).

[0086] [Table 1]

[0087] The electrodes of Examples 1-9, in which a certain amount of metal cations were introduced, passed the test specified in ANSI / AAMI EC12:2000 / (R)2020 4.2.2.4, which is the standard for disposable electrocardiogram electrodes. It is believed that by introducing metal cations in advance, further charging was minimized when voltage was applied in the aforementioned test, and the rise in inter-electrode potential was minimized. Furthermore, by suppressing the rise in inter-electrode potential, the discharge rate was also slowed during discharge, allowing the electrodes to pass the ANSI / AAMI EC12:2000 / (R)2020 4.2.2.4 test. In contrast, Comparative Example 1, which did not introduce metal cations, and Comparative Examples 2-4, which had insufficient amounts of metal cations introduced, failed the aforementioned test. In these comparative examples, it is believed that when discharge was made from a capacitor charged to 200V to the electrodes, ions in the gel intercalated into MXene, causing an ion imbalance between the electrodes, and thus failing Test 4. [Industrial applicability]

[0088] The electrodes relating to this disclosure can be used in any suitable application and are preferably used as biosignal sensing electrodes, but are not limited thereto.

[0089] The disclosures in this specification may include the following aspects: <1> An electrode comprising a film containing metal cation-containing layered material particles and a conductive gel portion in contact with the film, The metal cation-containing layered material particles have one or more layers and metal cations. The aforementioned layer is given by the following formula: M m X n (In the formula, M is at least one group 3, 4, 5, 6, or 7 metal containing at least one Ti atom, X is a carbon atom, a nitrogen atom, or a combination thereof. n is between 1 and 4, m is greater than n and less than or equal to 5. The layer body is represented by and includes a modification or termination 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, An electrode in which the content of the metal cation is 0.004 moles or more per gram of the film. <2> The metal cation comprises at least one of the following cations: Li cation, Na cation, and K cation. <1> The electrodes described above. <3> Biosignal sensing electrodes, <1> or <2> The electrodes described above. <4> The content of the metal cation is 0.1 moles or less per gram of the film. <1> ~ <3> The electrode described in one of the following. <5> (a) Layered material particles comprising one or more layers, The aforementioned layer is given by the following formula: M m X n (In the formula, M is at least one group 3, 4, 5, 6, or 7 metal containing at least one Ti atom, X is a carbon atom, a nitrogen atom, or a combination thereof. n is between 1 and 4, m is greater than n and less than or equal to 5. To prepare layered material particles comprising a layer body represented by and a modification or termination T (where T is at least one selected from the group consisting of hydroxyl groups, fluorine atoms, chlorine atoms, oxygen atoms, and hydrogen atoms) present on the surface of the layer body, (b) Mixing a dispersion containing the layered material particles with an aqueous solution containing metal cations to obtain a dispersion containing metal cation-containing layered material particles. (c) Using a dispersion containing the metal cation-containing layered material particles, obtain a film containing metal cation-containing layered material particles in which the metal cation content is 0.004 moles or more per gram of film, and (d) Forming a conductive gel portion on at least one surface of the film. A method for manufacturing electrodes, including <6> The metal cation comprises at least one of the following cations: Li cation, Na cation, and K cation. <5> The manufacturing method described above. <7> The content of the metal cation is 0.1 moles or less per gram of the film. <5> or <6> The manufacturing method described above. <8> (A) Layered material particles comprising one or more layers, The aforementioned layer is given by the following formula: M m X n (In the formula, M is at least one group 3, 4, 5, 6, or 7 metal containing at least one Ti atom, X is a carbon atom, a nitrogen atom, or a combination thereof. n is between 1 and 4, m is greater than n and less than or equal to 5. To prepare layered material particles comprising a layer body represented by and a modification or termination T (where T is at least one selected from the group consisting of hydroxyl groups, fluorine atoms, chlorine atoms, oxygen atoms, and hydrogen atoms) present on the surface of the layer body, (B) Obtain a precursor film containing layered material particles using a dispersion containing the layered material particles. (C) Contacting the precursor film with an aqueous solution containing metal cations to obtain a film containing metal cation-containing layered material particles in which the metal cation content is 0.004 moles or more per gram of film, and (D) Forming a conductive gel portion on at least one surface of the film. A method for manufacturing electrodes, including <9> In (C) above, the time for contacting the precursor film with the aqueous solution containing the metal cation is 30 minutes to 24 hours. <8> The manufacturing method described above. <10> The metal cation comprises at least one of the following cations: Li cation, Na cation, and K cation. <8> or <9> The manufacturing method described above. <11> The content of the metal cation is 0.1 moles or less per gram of the film. <8> ~ <10> A manufacturing method described in any one of the following. [Explanation of symbols]

[0090] 1a and 1b layers of body (M) m X n layer) 3a, 5a, 3b, 5b modified terminal T 7a, 7b MXene layers 10, 10a, 10b layered material particles

Claims

1. An electrode comprising a film containing metal cation-containing layered material particles and a conductive gel portion in contact with the film, The metal cation-containing layered material particles have one or more layers and metal cations. The aforementioned layer is given by the following formula: M ｍ X ｎ (In the formula, M is at least one group 3, 4, 5, 6, or 7 metal containing at least a Ti atom, X is a carbon atom, a nitrogen atom, or a combination thereof. n is between 1 and 4, m is greater than n and less than or equal to 5. The layer body is represented by and includes a modification or termination T present on the surface of the layer body (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), An electrode in which the content of the metal cation is 0.004 moles or more per gram of the film.

2. The electrode according to claim 1, wherein the metal cation comprises at least one cation selected from Li cations, Na cations, and K cations.

3. The electrode according to claim 1 or 2, which is a biosignal sensing electrode.

4. The electrode according to claim 1 or 2, wherein the content of the metal cation is 0.1 moles or less per gram of the film.

5. (a) Layered material particles comprising one or more layers, The aforementioned layer is given by the following formula: M ｍ X ｎ (In the formula, M is at least one group 3, 4, 5, 6, or 7 metal containing at least a Ti atom, X is a carbon atom, a nitrogen atom, or a combination thereof. n is between 1 and 4, m is greater than n and less than or equal to 5. To prepare layered material particles comprising a layer body represented by and a modification or termination T (where T is at least one selected from the group consisting of hydroxyl groups, fluorine atoms, chlorine atoms, oxygen atoms, and hydrogen atoms) present on the surface of the layer body, (b) Mixing a dispersion containing the layered material particles with an aqueous solution containing metal cations to obtain a dispersion containing metal cation-containing layered material particles. (c) Using a dispersion containing the metal cation-containing layered material particles, obtain a film containing metal cation-containing layered material particles in which the metal cation content is 0.004 moles or more per gram of film, and (d) Forming a conductive gel portion on at least one surface of the film. A method for manufacturing electrodes, including

6. The manufacturing method according to claim 5, wherein the metal cation comprises at least one cation from among Li cations, Na cations, and K cations.

7. The manufacturing method according to claim 5 or 6, wherein the content of the metal cation is 0.1 moles or less per gram of the film.

8. (A) Layered material particles comprising one or more layers, The aforementioned layer is given by the following formula: M ｍ X ｎ (In the formula, M is at least one group 3, 4, 5, 6, or 7 metal containing at least a Ti atom, X is a carbon atom, a nitrogen atom, or a combination thereof. n is between 1 and 4, m is greater than n and less than or equal to 5. To prepare layered material particles comprising a layer body represented by and a modification or termination T (where T is at least one selected from the group consisting of hydroxyl groups, fluorine atoms, chlorine atoms, oxygen atoms, and hydrogen atoms) present on the surface of the layer body, (B) Obtain a precursor film containing layered material particles using a dispersion containing the layered material particles. (C) Contacting the precursor film with an aqueous solution containing metal cations to obtain a film containing metal cation-containing layered material particles in which the metal cation content is 0.004 moles or more per gram of film, and (D) Forming a conductive gel portion on at least one surface of the film. A method for manufacturing electrodes, including

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

10. The manufacturing method according to claim 8 or 9, wherein the metal cation comprises at least one cation selected from Li cations, Na cations, and K cations.

11. The manufacturing method according to claim 8 or 9, wherein the content of the metal cation is 0.1 moles or less per gram of the film.

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