Graphene electrode coating for low-frequency electric field induction and preparation method thereof

Abstract

The invention belongs to the technical field of electrode coatings, and particularly relates to a graphene electrode coating for low-frequency electric field induction and a preparation method of the graphene electrode coating. The graphene electrode coating for low-frequency electric field induction comprises a conductive composite coating and a bonding layer, wherein the bonding layer is positioned between the conductive composite coating and a substrate; the conductive composite coating is prepared from graphene oxide, nitrogen-doped reduced graphene, carbon nanotubes, polyvinyl alcohol and epoxy resin, and the bonding layer is prepared from an acrylate monomer, a cross-linking agent, an initiator, a tackifier and a solvent. The graphene electrode coating disclosed by the invention has low-frequency electric field induction performance and high coating stability and adhesion capacity, and can be widely applied to the fields of bio-electricity signal sensing, environment monitoring and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of electrode coatings, and particularly relates to a graphene electrode coating for low-frequency electric field induction and a preparation method thereof. Background Art

[0002] Low-frequency electric field induction technology has important applications in the fields of electric power, environment, communication, etc. One of its core components is a highly sensitive induction electrode. Existing induction electrodes mainly use metal conductive materials or traditional carbon-based materials. These materials generally have the following deficiencies in a low-frequency electric field environment: (1) Insufficient sensitivity: Although metal electrodes have excellent electrical conductivity, their response ability to low-frequency electric field signals is weak, making it difficult to meet the requirements of high-sensitivity detection; (2) Poor environmental adaptability: Traditional carbon-based materials such as graphite electrodes are prone to performance degradation in high-humidity or high-temperature environments, resulting in unstable signals; (3) High process complexity: Existing preparation processes such as chemical vapor deposition or laser-induced technology have high costs and are not conducive to large-scale production; (4) Poor structural stability: Some conductive coatings are prone to peeling due to insufficient adhesion between the substrate and the coating, affecting long-term use performance.

[0003] The patent application with the application number 201810124398.8 discloses a graphene supercapacitor electrode sheet with low internal resistance and high power and a preparation method thereof. The graphene electrode sheet includes a current collector and graphene electrode paste. The graphene electrode paste includes graphene accounting for 75-93% by mass, a conductive agent accounting for 2-10%, and a binder accounting for 5-15%. The current collector is coated aluminum foil. The thickness of the graphene electrode sheet is 100-200 μm, and the areal density is 0.5-0.7 g / cm 3 . The graphene electrode sheet of this supercapacitor has characteristics such as low internal resistance and high power. The graphene electrode sheet of this invention has characteristics such as low internal resistance and high power, but it cannot solve the problem of low sensitivity.

[0004] With the improvement of the performance requirements for low-frequency electric field signal induction devices, there is an urgent need for an electrode material with high sensitivity, excellent environmental adaptability, stable structure, and low-cost preparation process. Summary of the Invention

[0005] Based on the above technical background, the main object of the present invention is to provide a graphene electrode coating for low-frequency electric field induction and a preparation method thereof, which significantly improves the low-frequency electric field induction performance, reduces the production cost and technical threshold at the same time, and provides a better technical solution for related fields.

[0006] To achieve the foregoing invention object, the technical solutions adopted by the present invention include:

[0007] The first aspect of the present invention is to provide a graphene electrode coating for low-frequency electric field induction. The graphene electrode coating for low-frequency electric field induction includes a conductive composite coating and an adhesive layer, and the adhesive layer and the conductive composite coating are arranged in a stacked manner;

[0008] The adhesive layer is prepared from raw materials in the following parts by weight:

[0009]

[0010] The conductive composite coating is prepared from raw materials in the following parts by weight:

[0011]

[0012] Preferably, the adhesive layer is prepared from raw materials in the following parts by weight:

[0013]

[0014] Preferably, the conductive composite coating is prepared from raw materials in the following parts by weight:

[0015]

[0016] Preferably, the crosslinking agent is selected from one or more of methacrylic acid, octenyl succinic anhydride, and isocyanate;

[0017] Preferably, the initiator is selected from one or more of benzoyl peroxide, dicumyl peroxide, and methyl ethyl ketone peroxide;

[0018] Preferably, the tackifier is selected from one or two of styrene-isoprene resin and polyacrylate;

[0019] Preferably, the solvent is selected from one or more of ethyl acetate, ethanol, methanol, and glycerol.

[0020] More preferably, the crosslinking agent is methacrylic acid;

[0021] The initiator is benzoyl peroxide;

[0022] The tackifier is styrene-isoprene resin;

[0023] The solvent is ethyl acetate.

[0024] The second aspect of the present invention is to provide a preparation method of the graphene electrode coating for low-frequency electric field induction described in the first aspect of the present invention. The preparation method includes the following steps:

[0025] Step 1: Mix acrylate monomer, crosslinking agent, initiator, tackifier, and solvent, and stir and disperse evenly to obtain an adhesive layer mixture;

[0026] Step 2: Mix graphene oxide, nitrogen-doped reduced graphene, carbon nanotubes, polyvinyl alcohol, and epoxy resin, and disperse them by ultrasonic treatment to obtain a conductive composite coating mixture.

[0027] Step 3: Apply the adhesive layer mixture onto the surface of the electrode to obtain an adhesive layer, apply the conductive composite coating mixture onto the surface of the adhesive layer to obtain a conductive composite coating, and then place it in an inert gas for low-temperature heat treatment to obtain a graphene electrode coating.

[0028] In Step 1,

[0029] Preferably, mix an acrylate monomer, a crosslinking agent, an initiator, a tackifier, and a solvent, and stir at a stirring speed of 2000 - 3000 rpm for 5 - 20 min to obtain an adhesive layer mixture.

[0030] In Step 2,

[0031] Preferably, the conditions for ultrasonic dispersion are: ultrasonic frequency is 30 - 50 kHz, and ultrasonic time is 20 - 45 min.

[0032] In Step 3,

[0033] Preferably, under an inert gas environment, perform heat treatment at a temperature of 180 - 250 °C for 20 - 45 min.

[0034] The beneficial effects of the present invention are as follows:

[0035] (1) The graphene electrode coating for low-frequency electric field induction according to the present invention includes a conductive composite coating and an adhesive layer. The mixture of graphene oxide (GO) and nitrogen-doped reduced graphene (N-RGO) used in the conductive composite coating effectively improves the conductivity and electric field response ability of the electrode coating, and significantly improves the induction sensitivity of the low-frequency electric field signal of the electrode coating; the added carbon nanotubes (CNT) construct a stable conductive network, and at the same time, the added epoxy resin as a binder enhances the mechanical stability and wear resistance of the electrode coating; adding polyvinyl alcohol (PVA) as a dispersant can greatly improve the uniformity of the conductive composite coating slurry, ensure the consistency of the thickness of the conductive coating, and further optimize the stability of the overall induction performance of the conductive coating.

[0036] The adhesive layer is located between the conductive composite coating and the substrate. The acrylate monomer and crosslinking agent used in the adhesive layer greatly improve the adhesion performance between the conductive coating and the substrate, and avoid peeling or cracking phenomena.

[0037] (2) The bonding layer is prepared by vacuum planetary dispersion and screen printing techniques, and the conductive composite coating is prepared by ultrasonic dispersion and screen printing techniques. Finally, the reduction of graphene oxide is completed through low-temperature heat treatment in an inert gas environment, which not only strengthens the conductive graphene network but also ensures the reduction of energy consumption and environmental friendliness of the preparation process.

[0038] (3) The graphene electrode coating of the present invention significantly improves the low-frequency electric field induction performance, coating stability and adhesion ability, has excellent adaptability, and can be widely applied in fields such as bioelectric signal sensing and environmental monitoring, providing important technical support for the development of the industry. Brief Description of the Drawings

[0039] Figure 1 Shows the structural schematic diagram of the graphene electrode coating for low-frequency electric field induction of the present invention; each layer is represented by an attached reference numeral

[0040] Figure 2 Shows the process flow chart of the preparation method of the present invention;

[0041] Figure 3 Shows the sensitivity test curve of the graphene electrode coating prepared in Example 1. Detailed Description of the Invention

[0042] The present invention will be described in detail below, and the features and advantages of the present invention will become clearer and more definite with these descriptions.

[0043] The first aspect of the present invention lies in providing a graphene electrode coating for low-frequency electric field induction. The graphene electrode coating for low-frequency electric field induction includes a conductive composite coating and a bonding layer. The bonding layer and the conductive composite coating are stacked, and the bonding layer is arranged between the conductive composite coating and the substrate, as Figure 1 shown.

[0044] The bonding layer is prepared from the following raw materials in parts by weight:

[0045]

[0046] Preferably, the bonding layer is prepared from the following raw materials in parts by weight:

[0047]

[0048] The conductive composite coating is prepared from the following raw materials in parts by weight:

[0049]

[0050] Preferably, the conductive composite coating is prepared from the following raw materials in parts by weight:

[0051]

[0052] In the adhesive layer of the present invention, acrylate provides the main film-forming and adhesion properties.

[0053] The crosslinking agent is selected from one or more of methacrylic acid, octenyl succinic anhydride, and isocyanate, preferably methacrylic acid. It can improve the mechanical strength and high-temperature resistance of the glue.

[0054] The initiator is selected from one or more of benzoyl peroxide, dicumyl peroxide, and methyl ethyl ketone peroxide, preferably benzoyl peroxide. The initiator can initiate the polymerization of acrylate monomers during the curing process.

[0055] The tackifier is selected from one or two of styrene-isoprene resin and polyacrylate, preferably styrene-isoprene resin. The tackifier can increase the initial adhesion and shear strength.

[0056] The solvent is selected from one or more of ethyl acetate, ethanol, methanol, and glycerol, preferably ethyl acetate. The added solvent in the present invention can adjust the viscosity and construction performance of the glue, facilitating coating.

[0057] In the conductive composite coating of the present invention, graphene oxide provides the conductive basis and the overall structural support of the material. Nitrogen-doped reduced graphene can enhance the conductivity and low-frequency electric field response ability. The added carbon nanotubes can construct a stable conductive network and improve the mechanical properties of the conductive composite coating. Polyvinyl alcohol is used as a dispersant to improve the dispersion uniformity of the slurry. Epoxy resin can enhance the adhesion and mechanical strength of the conductive composite coating.

[0058] The second aspect of the present invention lies in providing a preparation method of the graphene electrode coating for low-frequency electric field induction described in the first aspect of the present invention. The preparation method includes the following steps, as Figure 2 shown:

[0059] Step 1: Mix acrylate monomers, crosslinking agent, initiator, tackifier, and solvent, and stir and disperse evenly to obtain an adhesive layer mixture;

[0060] Step 2: Mix graphene oxide, nitrogen-doped reduced graphene, carbon nanotubes, polyvinyl alcohol, and epoxy resin, and ultrasonically disperse to obtain a conductive composite coating mixture;

[0061] Step 3: Apply the adhesive layer mixture on the surface of the electrode to obtain an adhesive layer, apply the conductive composite coating mixture on the surface of the adhesive layer to obtain a conductive composite coating, and then place it in an inert gas for low-temperature heat treatment to obtain a graphene electrode coating.

[0062] The above steps are specifically described below.

[0063] In Step 1, an acrylate monomer, a crosslinking agent, an initiator, a tackifier, and a solvent are mixed and, through vacuum planetary dispersion, stirred at a stirring speed of 2000 - 3000 rpm for 5 - 20 min. Preferably, they are stirred at a stirring speed of 2500 rpm for 10 min to obtain a bonding layer mixture.

[0064] In Step 2, the conditions for ultrasonic dispersion are: an ultrasonic frequency of 30 - 50 kHz and an ultrasonic time of 20 - 45 min.

[0065] Preferably, the conditions for ultrasonic dispersion are: an ultrasonic frequency of 40 kHz and an ultrasonic time of 30 min.

[0066] In Step 3, the bonding layer mixture is printed into a film on the surface of an electrode substrate through screen printing to obtain a bonding layer, and the conductive composite coating mixture is printed into a film on the surface of the bonding layer to obtain a conductive composite coating.

[0067] Under an inert gas environment, heat treatment is performed at a temperature of 180 - 250 °C for 20 - 45 min. In the inert gas, low-temperature reduction of graphene oxide forms a conductive graphene network, which can strengthen the adhesion performance between the coating and the substrate.

[0068] Preferably, under an inert gas environment, heat treatment is performed at a temperature of 210 °C for 30 min.

[0069] Examples

[0070] The present invention will be further illustrated by specific examples below. These examples are only for illustrating the present invention and are not used to limit the scope of the present invention. The raw materials used in the examples of the present invention are all purchased.

[0071] Example 1

[0072] Weigh the raw materials of the bonding layer according to the following parts by weight: 60 parts by weight of acrylate monomer, 6 parts by weight of crosslinking agent methacrylic acid, 2 parts by weight of initiator benzoyl peroxide, 2 parts by weight of tackifier styrene-isoprene resin, and 30 parts by weight of solvent ethyl acetate.

[0073] Weigh the raw materials of the conductive composite coating according to the following parts by weight: 2 parts by weight of graphene oxide, 0.5 parts by weight of nitrogen-doped reduced graphene, 1 part by weight of carbon nanotubes, 0.5 parts by weight of polyvinyl alcohol, and 96 parts by weight of epoxy resin.

[0074] Mix the acrylate monomer, crosslinking agent, initiator, tackifier, and solvent, and through vacuum planetary dispersion, stir at a stirring speed of 2500 rpm for 10 min to obtain a bonding layer mixture.

[0075] Mix graphene oxide, nitrogen-doped reduced graphene, carbon nanotubes, polyvinyl alcohol, and epoxy resin, and perform ultrasonic dispersion. The conditions for ultrasonic dispersion are: ultrasonic frequency is 40 kHz, and ultrasonic time is 30 min. A conductive composite coating mixture is obtained.

[0076] Print the adhesive layer mixture on the electrode surface into a film by screen printing to obtain an adhesive layer. Print the conductive composite coating mixture on the surface of the adhesive layer into a film by screen printing to obtain a conductive composite coating. Under an inert gas environment, perform heat treatment at a temperature of 210 °C for 30 min to obtain a graphene electrode coating.

[0077] Example 2

[0078] Weigh each raw material of the adhesive layer according to the following weight parts: 50 weight parts of acrylate monomer, 3 weight parts of crosslinking agent methacrylic acid, 1 weight part of initiator benzoyl peroxide, 1 weight part of tackifier styrene-isoprene resin, and 20 weight parts of solvent ethyl acetate.

[0079] Weigh each raw material of the conductive composite coating according to the following weight parts: 1 weight part of graphene oxide, 0.3 weight part of nitrogen-doped reduced graphene, 0.5 weight part of carbon nanotubes, 0.2 weight part of polyvinyl alcohol, and 93 weight parts of epoxy resin.

[0080] Mix the acrylate monomer, crosslinking agent, initiator, tackifier, and solvent, and perform vacuum planetary dispersion. Stir at a stirring speed of 2000 rpm for 20 min to obtain an adhesive layer mixture.

[0081] Mix graphene oxide, nitrogen-doped reduced graphene, carbon nanotubes, polyvinyl alcohol, and epoxy resin, and perform ultrasonic dispersion. The conditions for ultrasonic dispersion are: ultrasonic frequency is 30 kHz, and ultrasonic time is 45 min. A conductive composite coating mixture is obtained.

[0082] Print the adhesive layer mixture on the electrode surface into a film by screen printing to obtain an adhesive layer. Print the conductive composite coating mixture on the surface of the adhesive layer into a film by screen printing to obtain a conductive composite coating. Under an inert gas environment, perform heat treatment at a temperature of 180 °C for 45 min to obtain a graphene electrode coating.

[0083] Example 3

[0084] Weigh each raw material of the adhesive layer according to the following weight parts: 70 weight parts of acrylate monomer, 8 weight parts of crosslinking agent methacrylic acid, 3 weight parts of initiator benzoyl peroxide, 3 weight parts of tackifier styrene-isoprene resin, and 40 weight parts of solvent ethyl acetate.

[0085] Weigh each raw material of the conductive composite coating according to the following parts by weight: 3 parts by weight of graphene oxide, 0.8 parts by weight of nitrogen-doped reduced graphene, 2 parts by weight of carbon nanotubes, 0.7 parts by weight of polyvinyl alcohol, and 98 parts by weight of epoxy resin.

[0086] Mix acrylate monomer, crosslinking agent, initiator, tackifier and solvent, and disperse them by vacuum planetary dispersion at a stirring speed of 3000 rpm for 5 minutes to obtain a bonding layer mixture.

[0087] Mix graphene oxide, nitrogen-doped reduced graphene, carbon nanotubes, polyvinyl alcohol and epoxy resin, and perform ultrasonic dispersion. The conditions for ultrasonic dispersion are: ultrasonic frequency is 50 kHz, and ultrasonic time is 20 minutes. Obtain a conductive composite coating mixture.

[0088] Print the bonding layer mixture into a film on the electrode surface by screen printing to obtain a bonding layer. Print the conductive composite coating mixture into a film on the surface of the bonding layer by screen printing to obtain a conductive composite coating. Under an inert gas environment, heat-treat at a temperature of 250 °C for 20 minutes to obtain a graphene electrode coating.

[0089] Experimental Example

[0090] Experimental Example 1 Peel Strength Test

[0091] Perform peel strength tests on the graphene electrode coatings prepared in Examples 1 to 3 respectively.

[0092] The test process is as follows: Use an Instron 3345 tensile testing machine to test the low-frequency graphene electrode coating by the 90° tape peeling method (3 groups of samples, and take the average value of 5 tests for each group).

[0093] Test environment: Room temperature (25 °C), relative humidity 50%, peeling speed 50 mm / min. The test results are shown in Table 1.

[0094] Table 1 Peel Force Test Results

[0095]

[0096] The peeling width is 10 mm, and the peel strength calculation formula is: Peel strength = Peel force / Peeling width. The peel strength calculated according to this formula is shown in Table 2.

[0097] Table 2 Peel Strength

[0098]

[0099]

[0100] As can be seen from Table 2, the peel strength of the graphene electrode coatings prepared in Examples 1 to 3 is above 1.82 N / mm, indicating that the graphene electrode coatings of the present invention have a relatively high peel strength and good adhesion.

[0101] Sensitivity Test of Experimental Example 2

[0102] The sensitivity test was respectively carried out on the graphene electrode coating prepared in Example 1. The test process is as follows:

[0103] Electrode coating parameters: Conductive coating thickness: 10 μm; Adhesive layer thickness: 5 μm.

[0104] Test conditions: Input electric field strength: 10 V / m; Ambient temperature: 25 °C; Relative humidity: 50%.

[0105] Test instruments: Low-frequency signal generator (Agilent 33220A), signal acquisition system (Keysight DAQ970A). The test results are as Figure 3 shown.

[0106] From Figure 3 it can be seen that the induction sensitivity and signal-to-noise ratio of the graphene electrode coating prepared in Example 1 are relatively high.

[0107] The present invention has been described in detail above in combination with specific embodiments and exemplary examples, but these descriptions should not be construed as limiting the present invention. Those skilled in the art understand that without departing from the spirit and scope of the present invention, various equivalent substitutions, modifications or improvements can be made to the technical solutions and their implementation manners of the present invention, and these all fall within the scope of the present invention. The protection scope of the present invention is subject to the appended claims.

Claims

1. A graphene electrode coating for low-frequency electric field induction, characterized in that: The graphene electrode coating for low-frequency electric field induction comprises a conductive composite coating and a bonding layer, wherein the bonding layer and the conductive composite coating are stacked; The bonding layer is made from the following raw materials in parts by weight: The conductive composite coating is prepared from the following raw materials in parts by weight:

2. The graphene electrode coating for low-frequency electric field induction according to claim 1, characterized in that: The bonding layer is made from the following raw materials in parts by weight:

3. The graphene electrode coating for low-frequency electric field induction according to claim 1, characterized in that: The conductive composite coating is prepared from the following raw materials in parts by weight:

4. The graphene electrode coating for low-frequency electric field induction according to claim 1, characterized in that: The cross-linking agent is selected from one or more of methacrylic acid, octenic anhydride and isocyanate.

5. The graphene electrode coating for low-frequency electric field induction according to claim 1, characterized in that: The initiator is selected from one or more of benzoyl peroxide, dicumyl peroxide, and methyl ethyl ketone peroxide.

6. The graphene electrode coating for low-frequency electric field induction according to claim 1, characterized in that: The tackifier is selected from one or two of styrene-isoprene resin and polyacrylate; The solvent is selected from one or more of ethyl acetate, ethanol, methanol and glycerol.

7. A method for preparing a graphene electrode coating for low-frequency electric field induction according to any one of claims 1 to 6, characterized in that: The preparation method comprises the following steps: Step 1, mixing an acrylate monomer, a crosslinking agent, an initiator, a tackifier and a solvent, stirring and dispersing them uniformly to obtain a bonding layer mixture; Step 2, mixing graphene oxide, nitrogen-doped reduced graphene, carbon nanotubes, polyvinyl alcohol and epoxy resin, and ultrasonically dispersing them to obtain a conductive composite coating mixture; Step 3: Apply the bonding layer mixture to the electrode surface to obtain a bonding layer, apply the conductive composite coating mixture on the bonding layer surface to obtain a conductive composite coating, and then place it in an inert gas for low-temperature heat treatment to obtain a graphene electrode coating.

8. The preparation method according to claim 7, characterized in that: In step 1, The acrylate monomer, the crosslinking agent, the initiator, the tackifier and the solvent are mixed, and stirred at a stirring speed of 2000 to 3000 rpm for 5 to 20 minutes to obtain a bonding layer mixture.

9. The preparation method according to claim 7, characterized in that: In step 2, The conditions for ultrasonic dispersion are: ultrasonic frequency of 30 to 50 kHz, and ultrasonic time of 20 to 45 min.

10. The preparation method according to claim 7, characterized in that: In step 3, In an inert gas environment, heat treatment is performed at a temperature of 180 to 250° C. for 20 to 45 minutes.

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