CN111854595B

CN111854595B - Ion sensor based on MXene electrode and preparation method thereof

Info

Publication number: CN111854595B
Application number: CN202010858520.1A
Authority: CN
Inventors: 胡颖; 朱克福; 吴玉程; 金珂; 沈锦杰; 王枭杰; 常龙飞; 刘家琴
Original assignee: Hefei University of Technology
Current assignee: Hefei University of Technology
Priority date: 2020-08-24
Filing date: 2020-08-24
Publication date: 2022-03-11
Anticipated expiration: 2040-08-24
Also published as: CN111854595A

Abstract

The invention discloses an ion sensor based on MXene electrodes, and relates to the technical field of flexible ion sensors. The invention also comprises a preparation method of the ion sensor. The invention has the beneficial effects that: the ion sensor in the invention can directly use the electrode layer containing MXene as an electrode without electroplating a metal electrode.

Description

Ion sensor based on MXene electrode and preparation method thereof

Technical Field

The invention relates to the technical field of flexible ion sensors, in particular to an ion sensor based on MXene electrodes and a preparation method thereof.

Background

The gentle breeze blows the surface of water, and obvious ripples can be seen to the surface of water, and when some thing soaked in the water, water can be easily change self form and hold foreign matter. The molecules diffuse more easily in liquids than in solids and therefore are able to sense external stimuli more easily. When ions exist in the solution, the ions are easy to diffuse along with the solution, so that different electric signals can be brought to specific positions to be identified, for example, various cells in a biological system can acquire information through ion exchange. An ion sensor is a sensing system based on ion transport, which contains ions that move freely like liquid molecules, and thus has a stronger recognition ability for small stimuli of dynamics than other types of sensors. The ion sensor generally uses a flexible material as a substrate, ions are added into the flexible material, so that the ion sensor generates ion migration when being subjected to stress strain, and therefore the flexible material has the characteristics of the flexible material and the sensing function.

At present, most flexible sensors are researched by piezoresistive sensors, piezoresistive sensors and piezoelectric sensors, which are all based on an electronic transmission system. While sensors based on electronic transmission have achieved significant success in terms of sensing accuracy and speed, they are still limited in their interaction with biological systems. The ion sensor is based on an ion transmission system, so that the biological compatibility is more likely to be realized, and when the electronic flexible sensor acquires a signal, the resistance or capacitance change in the electronic flexible sensor can be detected only by inputting an external power supply, for example, a sacrificial layer and a substrate layer are sequentially generated on a substrate in the preparation method of the flexible sensor disclosed in the patent with the publication number of CN 109059749A; sputtering a metal layer on the substrate layer; and carrying out first photoetching and etching treatment on the metal layer to form the strain sensing device. However, when the ion sensor is stimulated, the potential difference generated by the internal ion migration can be directly measured by the device without providing an external power supply. The existing ionic sensor electrodes are generally metal electrodes and conductive nano materials, and the metal electrodes need to be electroplated on the surface of a polymer, so that the structure and the preparation steps of the ionic sensor are complicated.

MXene is a new two-dimensional crystalline material with a graphene-like layered structure composed of transition metal carbides or carbonitrides, with the chemical formula Mn +1XnTx, M being an early transition metal (e.g. Ti, V, Zn, Hf, Zr, Nb, Ta, Cr, Mo, Sc, Y, Lu, W), X being a C or C, N element, T representing a group O, OH, F, etc., n being 1, 2 or 3, and X being the number of T groups.

The ionic liquid is a liquid composed of anions and cations, such as KCl and NaCl, which is solid at normal temperature and can be converted into liquid at high temperature, and can be called as the ionic liquid. In the ionic compound, the charge quantity and radius of the anions and cations determine the binding force of the anions and cations, and the anions and cations have large volume, loose structure and small binding force and can be in a liquid state at room temperature.

Disclosure of Invention

The invention aims to solve the technical problem that the ion sensor in the prior art needs to electroplate a metal electrode on the surface of a polymer, so that the preparation process of the ion sensor structure is complex and consumes long time.

The invention solves the technical problems through the following technical means:

an MXene electrode-based ion sensor comprising an ionic polymer film and two electrode layers comprising MXene, the ionic polymer film being located between the two electrode layers comprising MXene, the ionic polymer film being made predominantly of an ionic liquid and a thermoplastic polyurethane.

The working principle is as follows: when the sensor senses stress strain, the part of the inside of the sensor facing to the bending direction is subjected to extrusion stress, and the space occupied by ions is reduced; the portion facing away from the bending direction is subjected to tensile stress, and the space that can be occupied by ions becomes large. When the sensor is subjected to bending strain, due to the fact that the volumes of anions and cations in the ionic liquid are different, the speeds of the anions and the cations reaching the electrodes are different, the ratio of the anions and the cations in the space of the middle layer is changed, and potential difference which can be detected in the upper electrode and the lower electrode is formed. Such signals can be captured by wires and external devices.

Has the advantages that: the ion sensor provided by the invention can directly use the electrode layer containing MXene as an electrode without electroplating a metal electrode, and has a simple structure.

Based on the structure and the working principle, the sensor can realize the sensing function without any external power supply, and is a passive sensor in the true sense.

Compared with graphene and other two-dimensional materials, MXene has good conductivity, and the surface of MXene has functional groups such as hydroxyl and oxygen, so that MXene has better stability in dispersion in a liquid phase, and has good application prospect in preparation of flexible equipment electrodes.

The room temperature ionic liquid has the characteristics of non-volatility, high heat resistance, nonflammability and the like, so that the room temperature ionic liquid can be widely applied to the fields of novel high-performance batteries, supercapacitors, sensors and the like.

Preferably, the electrode layer containing MXene is a conductive coating of Mxene or a conductive coating of a composite of MXene and CNT.

Preferably, the MXene is Ti₃C₂T_x。

Has the advantages that: as MXene is in a lamellar structure, after the dispersed liquid of the MXene is coated on the surface of a substance and dried, the MXene lamellar layers are not tightly connected, and the formed film is relatively brittle and has fewer conductive paths, the resistance of the MXene lamellar structure is higher, and the connection between the MXene lamellar layers can be increased by adding the CNT, so that the resistance of the MXene lamellar structure is greatly reduced, and the output signal of the sensor is favorably improved.

Preferably, the mass ratio of MXene to CNT is 1: 0-3.

Preferably, the mass ratio of MXene to CNT is 1: 1.

Has the advantages that: the mixing of the CNT and the MXene is beneficial to increasing the distance between MXene sheets, so that the MXene sheets can contain movable ions, and increasing the stability existing in the ion electrode, when the sensor is bent to the highest point, the sensing signal of the existing ion driver is not always kept at the open-circuit voltage signal and is reduced due to the fact that the electrode does not contain a space for containing the ions, and the ion sensor prepared from the MXene and the CNT electrode can be kept for a short time when the sensor is stopped at the highest point.

The invention also provides a preparation method of the ion sensor based on the MXene electrode, which comprises the following steps:

(1) adding the ionic liquid and the thermoplastic polyurethane into DMF (dimethyl formamide), stirring to prepare an ionic polymer layer solution, dripping the ionic polymer layer solution onto a glass plate, and drying to prepare an ionic polymer film;

(2) dripping electrode solution containing MXene material into the ionic polymer film obtained in the step (1), drying to form a film, and forming an electrode layer containing MXene on the ionic polymer film;

(3) and (3) removing the ionic polymer film superposed with the electrode layer containing MXene in the step (2) from the glass plate, then facing the electrode layer containing MXene to the glass plate, continuously dripping MXene electrode solution on the ionic polymer film, and drying to obtain the ion sensor based on the MXene electrode.

Preferably, the ionic liquid is 1-ethyl-3-methylimidazolium tetrafluoroborate (EMBBF)₄)。

Has the advantages that: EMBBF₄Is an ionic liquid capable of remaining in a liquid state at room temperature, and has a cation (EMI)⁺) Diameter of 0.606nm, anion (BF)₄-) diameter was 0.454nm, the cation diameter was larger than the anion, with a relatively large difference in the diameters of the anions and cations. Cationic (EMI) in comparison to other ionic liquids such as EMITFSI⁺) Diameter of 0.606nm, anion (TFSI)^-) Diameter 0.652nm, using EMBBF₄Better sensor signal strength is obtained. When the ionic polymer is stimulated, ions with small internal diameters are easier to migrate and more ions can be gathered in a narrow space, so that the difference of the diameters of the ionic liquid is larger, and the induced potential difference of the ionic sensor is favorably improved.

Preferably, the mass ratio of the ionic liquid to the thermoplastic polyurethane is 1-10: 5.

Preferably, the mass of the DMF is 10 to 30 times the mass of the thermoplastic polyurethane.

Preferably, the stirring temperature in the step (1) is 70 ℃, the rotating speed is 600r/min, and the time is 2-24 h.

Preferably, the size of the glass sheet in the step (1) is 25 x 75mm, and the volume of the ionomer layer solution dropped on the glass sheet is 1 to 3 mL.

Preferably, the drying temperature in the step (1) is 70 ℃, and the drying time is 2 h.

Preferably, the electrode solution containing MXene material is MXene electrode solution or mixed electrode solution of MXene and CNT.

Preferably, the mass ratio of MXene to CNT is 1: 0-3.

Preferably, the mass ratio of MXene to CNT is 1: 1.

Preferably, the concentration of the MXene electrode solution in the step (2) is 5-20 mg/mL.

Preferably, the drying temperature in the step (2) is 45 ℃ and the drying time is 2 h.

Preferably, the thickness of the ionic polymer film is 150-250 μm, and the thickness of the electrode layer containing MXene is 10-30 μm.

The invention has the advantages that: the ion sensor in the invention can directly use the electrode layer containing MXene as an electrode without electroplating a metal electrode.

The invention directly forms the electrode by directly dripping electrode material dispersion liquid on the surface of the ionic polymer and then drying the dispersion liquid to form a film. The preparation process of the invention does not need an electrode layer independent membrane making process and an electrode membrane and ionic polymer hot pressing process, and compared with an IPMC type ion sensor, the preparation method can greatly reduce the time required by electroplating and has simpler preparation steps.

As MXene is in a lamellar structure, after the dispersed liquid of the MXene is coated on the surface of a substance and dried, the MXene lamellar layers are not tightly connected, and the formed film is relatively brittle and has fewer conductive paths, the resistance of the MXene lamellar structure is higher, and the connection between the MXene lamellar layers can be increased by adding the CNT, so that the resistance of the MXene lamellar structure is greatly reduced, and the output signal of the sensor is favorably improved.

EMIBF₄Is an ionic liquid capable of remaining in a liquid state at room temperature, and has a cation (EMI)⁺) Diameter of 0.606nm, anion (BF)₄-) diameter was 0.454nm, the cation diameter was larger than the anion, with a relatively large difference in the diameters of the anions and cations. Cation (EMI) compared with other ionic liquids such as EMITFSI ionic liquid⁺) Diameter of 0.606nm, anion (TFSI)^-) Diameter 0.652nm, using EMBBF₄Better sensor signal strength is obtained. When the ionic polymer is stimulated, ions with smaller internal diameters are easier to migrate and can be more gathered in a narrow space, so that the difference of the diameters of the ionic liquid is larger, and the induced potential difference of the ionic sensor is favorably improved.

Drawings

FIG. 1 is a flow chart of a preparation process of an ion sensor based on MXene electrodes in the invention;

FIG. 2 is a schematic diagram of the operation of the ion sensor of the present invention;

FIG. 3 is a scanning electron micrograph of a cross section of an ion sensor according to example 1 of the present invention;

FIG. 4 is a graph showing the open-circuit voltage and strain displacement of an ion sensor in example 4 of the present invention;

fig. 5 is a graph showing the resistance change at two ends of an electrode when an ion sensor is strained in

embodiments

1 and 4 of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Test materials, reagents and the like used in the following examples are commercially available unless otherwise specified.

The specific techniques or conditions not specified in the examples can be performed according to the techniques or conditions described in the literature in the field or according to the product specification.

Fig. 1 is a flow chart of a preparation process of the ion sensor based on the MXene electrode, and fig. 2 is a working principle diagram of the ion sensor.

When the sensor is strained, the part of the inside of the sensor facing to the bending direction is subjected to extrusion stress, and the space occupied by ions is reduced; the portion facing away from the bending direction is subjected to tensile stress, and the space that can be occupied by ions becomes large. When the sensor is subjected to bending strain, the speeds of the anions and the cations reaching the electrodes are different due to different volumes of the anions and the cations, and the ratio of the anions and the cations in the space of the middle layer is changed, so that potential difference which can be detected in the upper electrode and the lower electrode is formed. Such signals can be captured by wires and external devices.

Example 1

Preparation method of ion sensor based on MXene electrode

(1) Preparation of the ionomer layer solution: mixing 0.5g of ionic liquid EMBBF₄And 1.0g of Thermoplastic Polyurethane (TPU) are added into 15g of DMF, and the mixture is stirred for 10 hours at the temperature of 70 ℃ and the rotating speed of 600r/min, so that the obtained TPU ionic liquid solution is the ionic polymer layer solution.

(2) Preparation of an ionic polymer membrane: the area is 25 x 75mm²The glass sheet mold plate was horizontally placed in a heating box, and the temperature in the heating box was adjusted to 70 ℃. Then 1ml of the ionomer layer solution was taken out each time by a pipette and added dropwise onto the glass plate for 2 times in total. Drying in a heating box for 2 hours, and then taking out to prepare the ionic polymer membrane.

(3) The ionomer membrane on the glass slide was placed horizontally on a heating platform and the temperature was adjusted to 45 ℃. And dripping 2ml of 10mg/ml MXene electrode solution on the surface of the ionic polymer film, and keeping for 2 hours until the solution is dried to form a film, so as to obtain the single-sided MXene electrode layer. The solute of the MXene electrode solution in this example is Ti₃C₂T_xDeionized water as solvent, adding Ti₃C₂T_xMixing the solute with deionized water, and performing ultrasonic treatment to obtain the MXene electrode solution. Individual MXene flakes are not infinitely stable in an environment where oxygen and water are present. However, they are in an anaerobic dehydration or dry air phaseIs stable.

(4) And (4) removing the ionic polymer film on which the MXene electrode layer is superposed in the step (3) from the glass plate, then facing the MXene electrode layer to the glass plate, flattening, and then repeating the step (3) to obtain the ion sensor with two layers of MXene electrodes. Fig. 3 is a scanning electron microscope image of the cross section of the prepared ion sensor, and it can be clearly seen that the ionic polymer film is positioned between the MXene electrode layers.

Cutting the sensor film into 10 x 20mm²The two copper wires are respectively stuck to the two MXene electrodes of the sensor by high-temperature silver colloid, and the two MXene electrodes are heated to 80 ℃ until the silver colloid is dry, so that the wires can derive electric signals sent by the sensor.

Example 2

Preparation method of ion sensor based on MXene electrode

(1) Preparation of the ionomer layer solution: 1g of ionic liquid EMBBF₄And 1.0g of Thermoplastic Polyurethane (TPU) are added into 15g of DMF, and the mixture is stirred for 20 hours at the temperature of 70 ℃ and the rotating speed of 600r/min, so that the obtained TPU ionic liquid solution is the ionic polymer layer solution.

(2) Preparation of an ionic polymer membrane: the area is 25 x 75mm²The glass sheet mold plate was horizontally placed in a heating box, and the temperature in the heating box was adjusted to 70 ℃. Then 1ml of the ionomer layer solution was taken out each time by a pipette and added dropwise onto the glass plate 3 times in total. Drying in a heating box for 2 hours, and then taking out to prepare the ionic polymer membrane.

(3) The ionomer membrane on the glass slide was placed horizontally on a heating platform and the temperature was adjusted to 45 ℃. And dripping 1ml of MXene electrode solution with the concentration of 5mg/ml on the surface of the ionic polymer film, and keeping for 2 hours until the MXene electrode solution is dried and formed into a film, so that the MXene electrode layer with one side is obtained. The solute of the MXene electrode solution in this example is Ti₃C₂T_xDeionized water as solvent, adding Ti₃C₂T_xMixing the solute with deionized water, and performing ultrasonic treatment to obtain the MXene electrode solution.

(4) And (4) removing the ionic polymer film on which the MXene electrode layer is superposed in the step (3) from the glass plate, then facing the MXene electrode layer to the glass plate, flattening, and then repeating the step (3) to obtain the ion sensor with two layers of MXene electrodes.

Example 3

Preparation method of ion sensor based on MXene electrode

(1) Preparation of the ionomer layer solution: 1g of ionic liquid EMBBF₄And 1.0g of Thermoplastic Polyurethane (TPU) are added into 15g of DMF, and the mixture is stirred for 10 hours at the temperature of 70 ℃ and the rotating speed of 600r/min, so that the obtained TPU ionic liquid solution is the ionic polymer layer solution.

(2) Preparation of an ionic polymer membrane: the area is 25 x 75mm²The glass sheet mold plate was horizontally placed in a heating box, and the temperature in the heating box was adjusted to 70 ℃. Then 3ml of ionomer layer solution was added dropwise to the glass slide with a pipette at a time. Drying in a heating box for 2 hours, and then taking out to prepare the ionic polymer membrane.

(3) The ionomer membrane on the glass slide was placed horizontally on a heating platform and the temperature was adjusted to 45 ℃. And dripping 2ml of 10mg/ml MXene electrode solution on the surface of the ionic polymer film, and keeping for 2 hours until the solution is dried to form a film, so as to obtain the single-sided MXene electrode layer. The solute of the MXene electrode solution in this example is Ti₃C₂T_xDeionized water as solvent, adding Ti₃C₂T_xMixing the solute with deionized water, and performing ultrasonic treatment to obtain the MXene electrode solution.

Cutting the sensor film into 10 x 20mm²The two copper wires are respectively stuck to two MXene electrodes of the sensor by high-temperature silver colloid, and the wires are heated to 80 ℃ until the silver colloid is dry to ensure that the wires are not damagedThe electrical signal emitted by the sensor can be derived.

Example 4

Preparation method of ion sensor based on MXene electrode

(3) The ionomer membrane on the glass slide was placed horizontally on a heating platform and the temperature was adjusted to 45 ℃. And dripping 1ml of mixed electrode solution of MXene and CNT with the concentration of 10mg/ml on the surface of the ionic polymer film, wherein the mass ratio of the MXene to the CNT is 1:1, and keeping for 2 hours until the mixed electrode solution is dried and formed into a film, so that an MXene/CNT electrode layer with one side is obtained.

In this embodiment, the solute of the mixed electrode solution of MXene and CNT is Ti₃C₂T_xAnd CNT in deionized water as solvent, adding Ti₃C₂T_xMixing the solute with deionized water, and performing ultrasonic treatment to obtain the MXene electrode solution. The preparation method of the MXene and CNT electrode layer solution comprises the following steps: preparing MXene into 10mg/mL solution (solvent is deionized water and storing in dark and low temperature), then mixing 5mL MXene solution (containing 50mg MXene and 5mL water) with 50mg CNT, adding 5mL deionized water, and mixing with ice water bath ultrasound for 2 hours. The concentration is the total mass of MXene to CNT to the volume of total deionized water.

(4) And (4) removing the ionic polymer film with the MXene/CNT electrode layer superposed in the step (3) from the glass plate, then facing the MXene/CNT electrode layer to the glass plate, flattening, and repeating the step (3) to obtain the ion sensor with two layers of MXene/CNT electrodes.

Will passCutting the sensor film into 5 × 20mm pieces²The two copper wires are respectively stuck to two MXene/CNT electrodes of the sensor by high-temperature silver adhesive, and the two copper wires are heated to 80 ℃ until the silver adhesive is dry so that the wires can lead out an electric signal sent by the sensor.

Fig. 4 is a graph comparing the open circuit voltage and the strain displacement of the ion sensor in this embodiment, and the ion sensor prepared by MXene and CNT electrodes can be maintained for a short time when the sensor stays at the highest point.

Fig. 5 is a graph showing the resistance change at two ends of the electrode when the sensor in this embodiment and embodiment 1 is strained, and it can be seen that when MXene is doped with CNT, the resistance of the MXene electrode layer can be significantly reduced.

The existing ion piezoelectric sensor electrode is mainly made of electroplated metal materials or nano conductive materials, the ion sensor is mainly divided into a single (cation) ion type and a double ion (ionic liquid, anion and cation) type, the single ion type generally uses nafion as an intermediate layer, the single ion type has better performance, the existing double ion type sensor has poorer performance, the invention is the double ion type sensor, and MXene is not applied to the ion sensor at present.

MXene is a two-dimensional lamellar material similar to graphene, van der Waals interaction force between adjacent nanosheets is strong, and aggregation and surface-to-surface self-re-accumulation of the MXene nanosheets are easy to occur during the preparation of the MXene film. When the sensor is bent, ions in the middle layer enter the electrode layer, so that the sensor can keep the sensing signal strength for a long time.

The sensing signal of the existing ion sensor is difficult to maintain and can be reduced when the sensor is bent to the highest point, as MXene is of a lamellar structure, after dispersed liquid of the MXene is dripped on the surface of a substance and dried, the connection between MXene lamellar layers is not tight, the formed film is relatively fragile and has fewer conductive paths, the resistance of the MXene lamellar structure is larger, and the addition of CNT can increase the relation between MXene lamellar layers, greatly reduce the resistance of the MXene lamellar structure and is beneficial to improving the output signal of the sensor.

The mixing of the CNT and the MXene is beneficial to increase the distance between the MXene sheets, enabling them to contain mobile ions, increasing the stability of the ions present in the electrode.

Example 5

Preparation method of ion sensor based on MXene electrode

(1) Preparation of the ionomer layer solution: 1g of ionic liquid EMBBF₄And 1.0g of Thermoplastic Polyurethane (TPU) are added into 15g of DMF, and the mixture is stirred for 10 hours at the temperature of 70 ℃ and the rotating speed of 800r/min, so that the obtained TPU ionic liquid solution is the ionic polymer layer solution.

(3) The ionomer membrane on the glass slide was placed horizontally on a heating platform and the temperature was adjusted to 45 ℃. And dripping 1ml of mixed electrode solution of MXene and CNT with the concentration of 10mg/ml on the surface of the ionic polymer film, wherein the mass ratio of the MXene to the CNT is 1:3, keeping for 2 hours until the mixed electrode solution is dried and formed into a film, and obtaining the MXene electrode layer with a single surface.

In this embodiment, the solute of the mixed electrode solution of MXene and CNT is Ti₃C₂T_xAnd CNT in deionized water as solvent, adding Ti₃C₂T_xMixing the solute with deionized water, and performing ultrasonic treatment to obtain the MXene electrode solution. The preparation method of the MXene and CNT electrode layer solution comprises the following steps: MXene was first sonicated to a 10mg/mL solution (solvent deionized water, no light cryogenically stored), then 2mL MXene solution was mixed with 60mg CNT, 6mL deionized water was added and mixed with ice water bath sonication for 2 hours. The concentration is the total mass of MXene to CNT to the volume of total deionized water.

Cutting the sensor film into 10 x 20mm²The two copper wires are respectively stuck to two MXene/CNT electrodes of the sensor by high-temperature silver adhesive, and the two copper wires are heated to 80 ℃ until the silver adhesive is dry so that the wires can lead out an electric signal sent by the sensor.

The above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.

Claims

1. An ion sensor based on MXene electrode, its characterized in that: the ionic polymer film comprises an ionic polymer film and two electrode layers containing MXene, wherein the ionic polymer film is positioned between the two electrode layers containing MXene, and the ionic polymer film is mainly made of ionic liquid and thermoplastic polyurethane;

the electrode layer containing MXene is an MXene conductive coating or a conductive coating of a composite material of MXene and CNT, the mass ratio of MXene to CNT is 1:0-3, and the MXene is Ti₃C₂T_x；

The preparation method of the ion sensor based on the MXene electrode comprises the following steps:

(1) adding the ionic liquid and the thermoplastic polyurethane into DMF (dimethyl formamide), stirring to prepare an ionic polymer layer solution, dropwise adding the ionic polymer layer solution onto a heating glass sheet, and drying to prepare an ionic polymer film;

2. A method of making an MXene electrode-based ion sensor of claim 1, comprising: the method comprises the following steps:

(1) adding the ionic liquid and thermoplastic polyurethane into DMF (dimethyl formamide), stirring to obtain an electrode layer solution, dropwise adding the electrode layer solution onto a heating glass sheet, and drying to obtain an ionic polymer film;

(2) dripping MXene electrode solution into the ionic polymer film obtained in the step (1), drying to form a film, and forming an electrode layer containing MXene on the ionic polymer film;

3. The method for preparing the MXene electrode-based ion sensor according to claim 2, wherein: the ionic liquid is 1-ethyl-3-methylimidazole tetrafluoroborate.

4. The method for preparing the MXene electrode-based ion sensor according to claim 2, wherein: the mass ratio of the ionic liquid to the thermoplastic polyurethane is 1-10: 5.

5. The method for preparing the MXene electrode-based ion sensor according to claim 2, wherein: the mass of the DMF is 10-30 times of that of the thermoplastic polyurethane.

6. The method for preparing the MXene electrode-based ion sensor according to claim 2, wherein: the MXene electrode solution also comprises CNT.

7. The method for preparing the MXene electrode-based ion sensor according to claim 6, wherein: the mass ratio of MXene to CNT in the MXene electrode solution is 1: 0-3.