Electric field induction electrode for optimizing low-frequency gain and preparation method thereof

Abstract

The invention belongs to the technical field of electric field induction, and particularly relates to an electric field induction electrode for optimizing low-frequency gain and a preparation method thereof. The graphite coating and the electromagnetic shielding layer are stacked on the surface of the substrate, the electric field induction electrode for optimizing the low-frequency gain sequentially comprises the substrate, the graphite coating and the electromagnetic shielding layer from bottom to top, and the conductive lead layer wraps the periphery of the electromagnetic shielding layer. The electric field induction electrode has high stability, excellent low-frequency gain characteristics and high low-frequency signal sensitivity, the influence of external electromagnetic interference on an electric field signal measurement result can be remarkably reduced, and the accuracy and stability of the measurement result are guaranteed. The electric field induction electrode is suitable for electric field induction application in various complex environments, and has a wide application prospect in the field of electric field induction.

Description

Technical Field

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

[0002] Electric field induction devices are becoming more and more widely used in many fields, including biomedical, environmental monitoring, smart home, and industrial automation. In order to improve the gain and accuracy of low-frequency electric field signals, researchers have begun to focus on the application of highly conductive materials, especially graphite materials.

[0003] Graphite materials have excellent electrical conductivity, which can effectively improve the sensitivity of electric field induction signals. At the same time, the graphite coating also has strong heat resistance and good mechanical strength, which helps to improve the stability and durability of the electrode structure. A single graphite coating is not sufficient to solve the electromagnetic interference problem, especially in a complex electromagnetic environment.

[0004] Therefore, how to solve the electromagnetic interference problem of the electrode and improve the gain of low-frequency electric field signals has become a problem to be solved at present. Summary of the Invention

[0005] Based on the above technical background, the main object of the present invention is to provide an electric field induction electrode for optimizing low-frequency gain and a preparation method thereof to overcome the deficiencies in the prior art.

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

[0007] In the first aspect of the present invention, there is provided an electric field induction electrode for optimizing low-frequency gain, and the electric field induction electrode for optimizing low-frequency gain includes a substrate, a graphite coating, an electromagnetic shielding layer, and a conductive lead layer;

[0008] The graphite coating and the electromagnetic shielding layer are stacked on the surface of the substrate. The electric field induction electrode for optimizing low-frequency gain includes a substrate, a graphite coating, and an electromagnetic shielding layer in sequence from bottom to top, and the conductive lead layer is wrapped around the electromagnetic shielding layer.

[0009] Preferably, the graphite coating is made of graphite oxide;

[0010] Preferably, the electromagnetic shielding layer is made of titanium dioxide and polyvinyl alcohol;

[0011] Preferably, the conductive lead layer is made of a conductive polymer material;

[0012] Preferably, the substrate is copper foil, stainless steel, or aluminum foil.

[0013] Preferably, the conductive polymer material is selected from one or more of polythiophene, polyaniline, and polypyrrole.

[0014] The low-frequency range described in the present invention refers to 20 Hz to 2 KHz.

[0015] The second aspect of the present invention lies in providing a method for preparing the electric field induction electrode with optimized low-frequency gain described in the first aspect of the present invention. The method includes the following steps:

[0016] Coat a graphite coating on a substrate, coat an electromagnetic shielding layer on the graphite coating, coat a conductive lead layer on the side surface of the electromagnetic shielding layer, then dry and cure, and finally perform annealing treatment.

[0017] Preferably, the method includes the following steps:

[0018] Step 1: Dissolve graphite oxide micropowder in an acid, perform magnetic stirring and centrifugation, add the washed precipitate to water, then add a reducing agent for reduction, and then centrifuge and wash the precipitate to obtain reduced graphene;

[0019] Step 2: Add the reduced graphene to a solvent and disperse it evenly to obtain a reduced graphene dispersion. Deposit the reduced graphene dispersion on the surface of the substrate by chemical vapor deposition. After the deposition is completed, perform high-temperature annealing treatment to obtain a graphite coating;

[0020] Step 3: Mix titanium dioxide and polyvinyl alcohol to obtain a slurry, and coat the slurry on the surface of the graphite coating to obtain an electromagnetic shielding layer;

[0021] Step 4: Add a conductive polymer material to a solvent and mix it evenly to obtain a conductive polymer solution. Coat the conductive polymer solution on the side surface of the electromagnetic shielding layer to form a conductive lead layer;

[0022] Step 5: Dry the coated electrode, and then perform annealing treatment to obtain the electric field induction electrode with optimized low-frequency gain.

[0023] In Step 1,

[0024] Preferably, dissolve graphite oxide micropowder in an acid, perform magnetic stirring for 2 to 4 h, and then centrifuge at a stirring speed of 4000 to 6000 rpm for 5 to 15 min;

[0025] Preferably, add the washed precipitate to water, then add a reducing agent and stir for reduction for 2 to 4 h. The addition amount of the reducing agent is 1.5 to 3 times the mass of the graphite oxide micropowder.

[0026] In Step 2,

[0027] Preferably, the concentration of the reduced graphene dispersion is 0.3 to 0.7 mg / mL;

[0028] Preferably, the conditions for the chemical vapor deposition are as follows: a carrier gas is introduced, and the carrier gas is argon, hydrogen or nitrogen. The deposition temperature is 800-1000 °C, the deposition time is 0.5-5 h, the carbon source is methane or ethylene, and the flow rates of the carrier gas and the carbon source are 50-200 cm 3 / min.

[0029] Preferably, the conditions for the high-temperature annealing treatment are as follows: the high-temperature annealing temperature is 1000-1200 °C, and the high-temperature annealing time is 60-120 min.

[0030] In step 3,

[0031] Preferably, titanium dioxide and polyvinyl alcohol are mixed in a mass ratio of (6-8):3.

[0032] In step 5,

[0033] Preferably, the drying temperature is 60-80 °C, and the drying time is 1-3 h;

[0034] Preferably, the temperature for the annealing treatment is 250-300 °C, and the time for the annealing treatment is 0.5-2 h.

[0035] The beneficial effects of the present invention are as follows:

[0036] (1) The electric field induction electrode of the present invention includes a substrate, a graphite coating, an electromagnetic shielding layer, and a conductive lead layer. The electric field induction electrode combines a highly conductive graphite coating with an advanced electromagnetic shielding layer design, which can not only effectively improve the sensitivity of low-frequency electric field signals, but also reduce the influence of external electromagnetic interference on the measurement results. The electric field induction electrode of the present invention has high stability, excellent low-frequency gain characteristics, and high low-frequency signal sensitivity, can significantly reduce the influence of external electromagnetic interference on the measurement results of electric field signals, ensure the accuracy and stability of the measurement results, is suitable for electric field induction applications in a variety of complex environments, and has broad application prospects.

[0037] (2) The substrate provides necessary mechanical support and electrical connection. Through ultrasonic cleaning and nitrogen drying treatment, the surface of the substrate is clean and grease-free, ensuring excellent contact with the graphite coating, thereby improving the overall stability and conductivity of the electrode structure. The clean substrate surface enhances the adhesion between the graphite coating and the substrate, reduces the contact resistance, and thus improves the conductive performance and signal transmission efficiency of the electrode.

[0038] (3) The graphite coating is composed of highly conductive graphite material and is deposited on the substrate by chemical vapor deposition. The thickness of the graphite coating is precisely controlled so as to optimize the electric field sensing ability, especially in terms of the gain of low-frequency signals. The graphite coating significantly improves the electric field sensing sensitivity of the electrode and the gain of low-frequency signals. At the same time, the high-temperature annealing treatment further improves the conductivity of the graphite coating, ensuring the improvement of the stability and reliability of the electric field sensing effect of the electrode.

[0039] (4) The electromagnetic shielding layer is layered and has a multi-layer grid structure or a mesh inlay design on its outer surface. This structure can improve the shielding effect and can provide better mechanical strength and anti-interference ability in practical applications. The electromagnetic shielding layer effectively isolates external electromagnetic interference. Compared with the traditional single-layer shielding structure, the grid structure has a higher shielding efficiency. This structure can be flexibly adjusted according to the working environment and application requirements to ensure the best electromagnetic shielding effect in various environments, effectively filtering electromagnetic noise and ensuring the purity of the electric field signal and the accuracy of the measurement results.

[0040] (5) The preparation method of the electric field sensing electrode of the present invention is simple and suitable for large-scale production. Description of the Drawings

[0041] Figure 1 Showing a schematic structural diagram of an electric field sensing electrode for optimizing low-frequency gain according to the present invention;

[0042] Figure 2 Showing a flowchart of the preparation of the electric field sensing electrode according to the present invention. Detailed Embodiments

[0043] 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.

[0044] In the first aspect of the present invention, there is provided an electric field sensing electrode for optimizing low-frequency gain, and the electric field sensing electrode for optimizing low-frequency gain includes a substrate, a graphite coating, an electromagnetic shielding layer, and a conductive lead layer.

[0045] The graphite coating and the electromagnetic shielding layer are stacked on the surface of the substrate. The electric field sensing electrode for optimizing low-frequency gain includes the substrate, the graphite coating, and the electromagnetic shielding layer in sequence from bottom to top. The conductive lead layer is wrapped around the electromagnetic shielding layer, as Figure 1 shown.

[0046] The graphite coating is made from graphite oxide and has a thickness of 10 - 30 μm.

[0047] The electromagnetic shielding layer is made of titanium dioxide and polyvinyl alcohol, and has a thickness of 30 - 60 μm. The outer surface of the electromagnetic shielding layer has a multi-layer grid structure or reticular inlay. It has a high degree of design flexibility and can adjust its geometric shape, size, and layout according to actual needs to ensure the best electromagnetic shielding effect in different working environments. This adjustability makes the application of this electrode structure more extensive in various industrial and scientific research fields, meeting the diverse and high-precision requirements.

[0048] The conductive lead layer is made of a conductive polymer material, and the conductive polymer material is selected from one or more of polythiophene, polyaniline, and polypyrrole. Preferably, the conductive lead layer is made of polythiophene (PEDOT).

[0049] The substrate is copper foil, stainless steel, or aluminum foil.

[0050] Through the combination of the graphite coating and the electromagnetic shielding layer in the present invention, the response performance of the electrode in the low-frequency band has been greatly improved, and this electrode structure can effectively improve the response sensitivity of the low-frequency electric field signal. The gain and stability of the low-frequency signal are the keys to many electric field induction applications. The present invention optimizes the electrode structure and preparation method to ensure the efficient capture and accurate measurement of the low-frequency signal by the electric field induction electrode.

[0051] The second aspect of the present invention lies in providing a method for preparing the electric field induction electrode with optimized low-frequency gain described in the first aspect of the present invention. The method includes the following steps:

[0052] Coat a graphite coating on the substrate, coat an electromagnetic shielding layer on the graphite coating, coat a conductive lead layer on the side of the electromagnetic shielding layer, then dry and cure, and finally perform an annealing treatment.

[0053] Preferably, as Figure 2 shown, the method includes the following steps:

[0054] Step 1: Dissolve graphite oxide micropowder in an acid, perform magnetic stirring and centrifugation, add the washed precipitate to water, then add a reducing agent for reduction, and then centrifuge and wash the precipitate to obtain reduced graphene;

[0055] Step 2: Add the reduced graphene to a solvent and disperse it evenly to obtain a reduced graphene dispersion. Deposit the reduced graphene dispersion on the surface of the substrate by chemical vapor deposition. After the deposition is completed, perform a high-temperature annealing treatment to obtain a graphite coating;

[0056] Step 3: Mix titanium dioxide and polyvinyl alcohol to obtain a slurry, and coat the slurry on the surface of the graphite coating to obtain an electromagnetic shielding layer;

[0057] Step 4: Add the conductive polymer material into a solvent and mix evenly to obtain a conductive polymer solution, and coat the conductive polymer solution on the side of the electromagnetic shielding layer to form a conductive lead layer;

[0058] Step 5: Dry the coated electrode, and then perform annealing treatment to obtain an electric field induction electrode with optimized low-frequency gain.

[0059] The above steps are specifically described below.

[0060] In Step 1, the acid is selected from one of hydrochloric acid, sulfuric acid, and acetic acid, preferably hydrochloric acid.

[0061] Dissolve the graphite oxide micropowder in the acid, place it in ice, and stir magnetically for 2 - 4 h, and then centrifuge at a stirring speed of 4000 - 6000 rpm for 5 - 15 min.

[0062] Preferably, dissolve the graphite oxide micropowder in the acid, place it in ice, and stir magnetically for 3 h, and then centrifuge at a stirring speed of 5000 rpm for 10 min.

[0063] After centrifugation, wash the precipitate alternately with deionized water and ethanol for 2 - 5 times, preferably wash the precipitate alternately with deionized water and ethanol for 3 times to remove residual hydrochloric acid and other impurities.

[0064] Add the washed precipitate into water, and then add a reducing agent and stir to reduce for 2 - 4 h. The addition amount of the reducing agent is 1.5 - 3 times the mass of the graphite oxide micropowder.

[0065] Preferably, add the washed precipitate into water, and then add NaBH 4 Stir and reduce for 3 h. The addition amount of the reducing agent is 2 times the mass of the graphite oxide micropowder.

[0066] After the reduction reaction, centrifuge, and wash the precipitate with water for 2 - 4 times, preferably wash the precipitate with water for 3 times to remove unreacted NaBH 4 and NaOH.

[0067] In Step 2, select a highly conductive metal material as the electrode substrate. The highly conductive metal material is copper foil, stainless steel, or aluminum foil. First, use an ultrasonic cleaner to clean the electrode substrate in deionized water and ethanol to remove surface grease and impurities. After cleaning, dry the electrode substrate with clean nitrogen to ensure that there is no residual moisture on the surface.

[0068] Disperse the reduced graphene in a solvent evenly to obtain a reduced graphene dispersion with a concentration of 0.3 - 0.7 mg / mL.

[0069] Preferably, disperse the reduced graphene in ethanol evenly to obtain a reduced graphene dispersion with a concentration of 0.5 mg / mL.

[0070] A high-purity graphite coating is deposited on the surface of a substrate by chemical vapor deposition (CVD) to form a solid conductive substrate. The conditions for the chemical vapor deposition are as follows: a carrier gas is introduced, and the reduced graphene dispersion is introduced into the CVD reactor through the carrier gas. The carrier gas is argon, hydrogen or nitrogen to create a stable gas flow environment. The deposition temperature is 800-1000 °C, and the deposition time depends on the required coating thickness, which is 0.5-5 h. The carbon source is methane or ethylene, and the flow rates of the carrier gas and the carbon source are controlled. The flow rates of the carrier gas and the carbon source are 50-200 cm 3 / min. To ensure a good electric field induction effect, a relatively thick graphite coating is required to enhance the electric field induction ability, which is 10-30 μm.

[0071] Preferably, the conditions for the chemical vapor deposition are as follows: a carrier gas is introduced, and the reduced graphene dispersion is introduced into the CVD reactor through the carrier gas. The carrier gas is argon, the deposition temperature is 900 °C, the deposition time depends on the required coating thickness, which is 0.5-5 h, the carbon source is ethylene, and the flow rates of the carrier gas and the carbon source are 100 cm 3 / min. The thickness of the graphite coating is 15-25 μm.

[0072] The conditions for the high-temperature annealing treatment are: the high-temperature annealing temperature is 1000-1200 °C, and the high-temperature annealing time is 60-120 min.

[0073] Preferably, the conditions for the high-temperature annealing treatment are: the high-temperature annealing temperature is 1100 °C, and the high-temperature annealing time is 100 min. High-temperature annealing helps to improve the lattice structure of the graphene layer, reduce defects, and enhance the conductivity and electric field induction performance of the coating.

[0074] In the present invention, by optimizing the thickness of the graphite coating and combining the high-temperature annealing treatment process, the electric field induction ability and conductivity of the coating are significantly improved, especially in terms of the low-frequency signal gain, and obvious improvement is achieved.

[0075] In step 3, titanium dioxide and polyvinyl alcohol are mixed in a mass ratio of (6-8):3. Preferably, titanium dioxide and polyvinyl alcohol are mixed in a mass ratio of 7:3.

[0076] The slurry is uniformly coated on the prepared graphite coating by a doctor blade method to form an electromagnetic shielding layer with a multi-layer grid structure.

[0077] The electromagnetic shielding layer described in the present invention has a layered structure. This layered structure has a multi-layer grid or mesh inlay design, and a dense grid structure is formed on the outer surface, which can effectively shield external electromagnetic interference. The size and shape of the grid structure can be flexibly adjusted according to specific application requirements, so as to ensure the best electromagnetic shielding effect in different working environments, effectively filter electromagnetic noise, and ensure the purity of the electric field signal and the accuracy of the measurement results.

[0078] In step 4, the conductive polymer material is selected from one or more of polythiophene (PEDOT), polyaniline, and polypyrrole.

[0079] Preferably, the conductive polymer material is polythiophene.

[0080] The solvent is water or ethanol. Appropriate deionized water or ethanol is added for dilution to adjust the viscosity of the PEDOT solution to make it suitable for inkjet printing.

[0081] Use inkjet printing technology to precisely print the conductive polymer material on the edge of the electromagnetic shielding layer to form a conductive lead layer to ensure the electrical connection between the electromagnetic shielding layer and the external circuit.

[0082] In step 5, the drying temperature is 60-80°C and the drying time is 1-3h.

[0083] Preferably, the drying temperature is 70°C and the drying time is 2h to ensure complete curing of the electromagnetic shielding layer.

[0084] The temperature of the annealing treatment is 250-300°C and the time of the annealing treatment is 0.5-2h.

[0085] Preferably, the temperature of the annealing treatment is 270°C and the time of the annealing treatment is 1h to enhance the adhesion between the coatings and improve the stability and conductivity of the electrode structure.

[0086] Examples

[0087] The present invention is further illustrated by the following specific examples. 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 commercially available.

[0088] Example 1

[0089] Dissolve 1 g of graphite oxide micro powder in 10 ml of concentrated hydrochloric acid, and then perform magnetic stirring treatment in ice for 3 h. Centrifuge the stirred mixture at 5000 rpm for 10 min. Wash the precipitate alternately with deionized water and alcohol three times to remove residual hydrochloric acid and other impurities. Then, redisperse the washed precipitate into 20 ml of deionized water, and add 2 g of NaBH to the deionized water4 And continuously stir for 3 h for the reduction reaction. After the reduction reaction, centrifuge and wash the precipitate with water 3 times to remove unreacted NaBH 4 and NaOH to obtain reduced graphene oxide.

[0090] Disperse the reduced graphene oxide uniformly in 70% ethanol to obtain a reduced graphene oxide dispersion with a concentration of 0.5 mg / ml. First, use an ultrasonic cleaner to clean the electrode substrate in deionized water and ethanol to remove surface grease and impurities. After cleaning, dry the electrode substrate with clean nitrogen to ensure that there is no residual moisture on the surface. Place the pretreated electrode substrate into a CVD reactor. Deposit a high-purity graphite coating on the substrate surface by chemical vapor deposition (CVD). The conditions for the chemical vapor deposition are as follows: introduce a carrier gas, and the reduced graphene oxide dispersion is introduced into the CVD reactor through the carrier gas. The carrier gas is argon, the deposition temperature is 900 °C, the deposition time depends on the required coating thickness, the deposition time is 2 - 3 h, the carbon source is ethylene, and the flow rates of the carrier gas and the carbon source are 100 cm 3 / min. After deposition, perform a high-temperature annealing treatment at 1100 °C for 100 min, and the thickness of the graphite coating is 20 μm.

[0091] Mix titanium dioxide nanoparticles and polyvinyl alcohol in a mass ratio of 7:3 to obtain a slurry, and uniformly coat the slurry on the prepared graphite coating by the doctor blade method to form an electromagnetic shielding layer with a multi-layer grid structure on the surface.

[0092] Add deionized water or ethanol to poly(3,4-ethylenedioxythiophene) (PEDOT) for dilution, adjust the viscosity of the PEDOT solution to make it suitable for inkjet printing. Use inkjet printing technology to precisely print the conductive polymer material poly(3,4-ethylenedioxythiophene) on the side of the electromagnetic shielding layer to obtain a conductive lead layer.

[0093] Place the coated electrode in an oven, heat it to 70 °C and dry for 2 h, then heat it to 270 °C for annealing treatment for 1 h to obtain an electric field induction electrode.

[0094] Example 2

[0095] Dissolve 1 g of graphite oxide micropowder in 10 ml of concentrated hydrochloric acid, and then perform magnetic stirring treatment in ice for 2 h. Centrifuge the stirred mixture at 4000 rpm for 15 min. Wash the precipitate with deionized water and alcohol alternately three times to remove residual hydrochloric acid and other impurities. Then, redisperse the washed precipitate into 20 ml of deionized water, and add 2 g of NaBH 4 and continuously stir for 2 h for the reduction reaction. After the reduction reaction, centrifuge and wash the precipitate 3 times with water to remove unreacted NaBH 4 and NaOH to obtain reduced graphene oxide.

[0096] The reduced graphene is uniformly dispersed in 70% ethanol to obtain a reduced graphene dispersion with a concentration of 0.3 mg / ml. First, the electrode substrate is cleaned in deionized water and ethanol using an ultrasonic cleaner to remove surface grease and impurities. After cleaning, the electrode substrate is dried with clean nitrogen gas to ensure no moisture remains on the surface. The pretreated electrode substrate is placed in a CVD reactor. A high-purity graphite coating is deposited on the substrate surface by chemical vapor deposition (CVD). The conditions for the chemical vapor deposition are as follows: a carrier gas is introduced, and the reduced graphene dispersion is introduced into the CVD reactor through the carrier gas. The carrier gas is argon, the deposition temperature is 800 °C, the deposition time depends on the required coating thickness, the deposition time is 2 - 3 h, the carbon source is ethylene, and the flow rates of the carrier gas and the carbon source are 50 cm 3 / min. After deposition, a high-temperature annealing treatment is carried out at 1000 °C for 120 min, and the thickness of the graphite coating is 20 μm.

[0097] Titanium dioxide nanoparticles and polyvinyl alcohol are mixed in a mass ratio of 6:3 to obtain a slurry. The slurry is uniformly coated on the prepared graphite coating by the doctor blade method to form an electromagnetic shielding layer with a multi-layer grid structure on the surface.

[0098] Deionized water or ethanol is added to poly(3,4-ethylenedioxythiophene) (PEDOT) for dilution to adjust the viscosity of the PEDOT solution to make it suitable for inkjet printing. The conductive polymer material poly(3,4-ethylenedioxythiophene) is precisely printed on the side of the electromagnetic shielding layer using inkjet printing technology to obtain a conductive lead layer.

[0099] The coated electrode is placed in an oven, heated to 60 °C and dried for 3 h, and then heated to 250 °C for an annealing treatment for 2 h to obtain an electric field induction electrode.

[0100] Example 3

[0101] 1 g of graphite oxide micro powder is dissolved in 10 ml of concentrated hydrochloric acid, and then magnetic stirring treatment is carried out in ice for 4 h. The stirred mixture is centrifuged at 6000 rpm for 5 min. The precipitate is washed alternately with deionized water and alcohol three times to remove residual hydrochloric acid and other impurities. Then, the washed precipitate is redispersed in 20 ml of deionized water, and 2 g of NaBH 4 is added to the deionized water and continuous stirring is carried out for 4 h for the reduction reaction. After the reduction reaction, centrifugation is carried out and the precipitate is washed with water 3 times to remove unreacted NaBH 4 and NaOH to obtain reduced graphene.

[0102] The reduced graphene is uniformly dispersed in 70% ethanol to obtain a reduced graphene dispersion with a concentration of 0.7 mg / ml. First, the electrode substrate is cleaned in deionized water and ethanol using an ultrasonic cleaner to remove surface grease and impurities. After cleaning, the electrode substrate is dried with clean nitrogen gas to ensure no moisture remains on the surface. The pretreated electrode substrate is placed in a CVD reactor. A high-purity graphite coating is deposited on the substrate surface by chemical vapor deposition (CVD). The conditions for the chemical vapor deposition are as follows: a carrier gas is introduced, and the reduced graphene dispersion is introduced into the CVD reactor through the carrier gas. The carrier gas is argon, the deposition temperature is 1000 °C, the deposition time depends on the required coating thickness, the deposition time is 2 - 3 h, the carbon source is ethylene, and the flow rates of the carrier gas and the carbon source are 200 cm 3 / min. After deposition, a high-temperature annealing treatment is carried out at 1200 °C for 60 min, and the thickness of the graphite coating is 20 μm.

[0103] Titanium dioxide nanoparticles and polyvinyl alcohol are mixed in a mass ratio of 8:3 to obtain a slurry. The slurry is uniformly coated on the prepared graphite coating by the doctor blade method to form an electromagnetic shielding layer with a multi-layer grid structure on the surface.

[0104] Deionized water or ethanol is added to poly(3,4-ethylenedioxythiophene) (PEDOT) for dilution to adjust the viscosity of the PEDOT solution to make it suitable for inkjet printing. The conductive polymer material poly(3,4-ethylenedioxythiophene) is precisely printed on the side of the electromagnetic shielding layer using inkjet printing technology to obtain a conductive lead layer.

[0105] The coated electrode is placed in an oven, heated to 80 °C and dried for 1 h, and then heated to 300 °C for an annealing treatment for 0.5 h to obtain an electric field induction electrode.

[0106] Experimental Example

[0107] Experimental Example 1: Test of Electric Field Induction Signal Gain

[0108] A comparative experiment on the electric field induction signal gain is carried out for the electric field induction electrode prepared in Example 1 and a traditional electrode (metal electrode) respectively. The test frequency range is 1 Hz - 10 kHz; the experimental environment is a low-noise environment without external electromagnetic interference. The test results are shown in Table 1.

[0109] Table 1

[0110]

[0111] As can be seen from Table 1, in the range of 1 Hz to 100 Hz, the electrode signal gain of the electric field induction electrode prepared in Example 1 is increased by up to +9.8 dB - +10.5 dB compared with the traditional electrode. It shows that the electric field induction electrode of the present invention has significant signal gain in the low-frequency range through the high conductivity of the graphite coating and the anti-interference ability of the electromagnetic shielding layer, indicating that the electric field induction electrode of the present invention can effectively improve the sensitivity of low-frequency signals.

[0112] Experimental Example 2 Electromagnetic Interference Suppression Test

[0113] The anti-interference capabilities of the electric field induction electrode prepared in Example 1 and the traditional electrode (metal electrode) under external electromagnetic interference were respectively tested. Experimental conditions: Interference source: AC power supply with frequencies of 50 Hz and 100 Hz, and the electromagnetic field intensity is 100 mA / m. Measurement method: Use an electric field probe to measure the interference signal received on the electrode surface. The test results are shown in Table 2.

[0114] Table 2

[0115]

[0116] As can be seen from Table 2, when the electric field induction electrode prepared in Example 1 is under external electromagnetic interference, it can effectively suppress the interference signal. Especially at higher frequencies, such as 50 Hz and 100 Hz, the suppression effect of the electric field induction electrode prepared in Example 1 is obvious, and the signal suppression can reach more than 16.3 dB. It shows that the electric field induction electrode of the present invention can effectively suppress the interference signal.

[0117] Experimental Example 3 Electric Field Induction Sensitivity Test

[0118] The low-frequency electric field induction signal response sensitivity tests were respectively carried out on the electric field induction electrode prepared in Example 1 and the traditional electrode (metal electrode). The test frequency range: 10 Hz - 10 kHz. The test results are shown in Table 3.

[0119] Table 3

[0120]

[0121] As can be seen from Table 3, the sensitivity of the electric field induction electrode prepared in Example 1 is increased by more than 2% compared with the traditional electrode, and the maximum increase is 75%. It shows that the electric field induction electrode of the present invention has been effectively improved in sensitivity compared with the traditional electrode.

[0122] The present invention has been described in detail in conjunction with specific embodiments and exemplary examples. However, 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 all of these fall within the scope of the present invention. The protection scope of the present invention shall be subject to the appended claims.

Claims

1. An electric field sensing electrode for optimizing low frequency gain, characterized in that: The electric field induction electrode for optimizing low-frequency gain comprises a substrate, a graphite coating, an electromagnetic shielding layer and a conductive lead layer; The graphite coating and the electromagnetic shielding layer are stacked on the surface of the substrate, the electric field induction electrode for optimizing low-frequency gain includes a substrate, a graphite coating, and an electromagnetic shielding layer from bottom to top, and the conductive lead layer is wrapped around the electromagnetic shielding layer.

2. The electric field sensing electrode with optimized low frequency gain according to claim 1, characterized in that: The graphite coating is made of graphite oxide; The electromagnetic shielding layer is made of titanium dioxide and polyvinyl alcohol; The conductive lead layer is made of conductive polymer material; The substrate is copper foil, stainless steel or aluminum foil.

3. The electric field sensing electrode with optimized low frequency gain according to claim 2, characterized in that: The conductive polymer material is selected from one or more of polythiophene, polyaniline and polypyrrole.

4. A method for preparing an electric field sensing electrode with optimized low-frequency gain according to any one of claims 1 to 3, characterized in that: The method comprises the following steps: A graphite coating is coated on the substrate, an electromagnetic shielding layer is coated on the graphite coating, a conductive lead layer is coated on the side of the electromagnetic shielding layer, and then the layers are dried and solidified, and finally an annealing treatment is performed.

5. The method according to claim 4, characterized in that The method comprises the following steps: Step 1, dissolving graphite oxide powder in acid, performing magnetic stirring and centrifugation, adding the washed precipitate into water, then adding a reducing agent for reduction, then centrifuging, washing the precipitate, and obtaining reduced graphene; Step 2, adding the reduced graphene to a solvent and dispersing it uniformly to obtain a reduced graphene dispersion, depositing the reduced graphene dispersion on the surface of the substrate by chemical vapor deposition, and after the deposition is completed, performing a high temperature annealing treatment to obtain a graphite coating; Step 3, mixing titanium dioxide and polyvinyl alcohol to obtain a slurry, and coating the slurry on the surface of the graphite coating to obtain an electromagnetic shielding layer; Step 4, adding a conductive polymer material to a solvent and mixing them evenly to obtain a conductive polymer solution, and coating the conductive polymer solution on the side of the electromagnetic shielding layer to form a conductive lead layer; Step 5: Dry the coated electrode and then perform annealing to obtain an electric field sensing electrode with optimized low-frequency gain.

6. The method according to claim 5, characterized in that In step 1, Dissolve the graphite oxide powder in acid, stir magnetically for 2 to 4 hours, and then centrifuge at a stirring speed of 4000 to 6000 rpm for 5 to 15 minutes; The washed precipitate is added into water, and then a reducing agent is added and stirred for reduction for 2 to 4 hours. The amount of reducing agent added is 1.5 to 3 times the mass of the graphite oxide powder.

7. The method according to claim 5, characterized in that In step 2, The concentration of the reduced graphene dispersion is 0.3-0.7 mg / mL; The conditions of the chemical vapor deposition are: introducing a carrier gas, the carrier gas is argon, hydrogen or nitrogen, the deposition temperature is 800-1000°C, the deposition time is 0.5-5h, the carbon source is methane or ethylene, and the flow rate of the carrier gas and the carbon source is 50-200cm 3 / min.

8. The method according to claim 5, characterized in that In step 2, The conditions of the high temperature annealing treatment are: the high temperature annealing temperature is 1000-1200° C., and the high temperature annealing time is 60-120 min.

9. The method according to claim 5, characterized in that In step 3, Titanium dioxide and polyvinyl alcohol are mixed in a mass ratio of (6-8):

3.

10. The method according to claim 5, characterized in that In step 5, The drying temperature is 60-80°C and the drying time is 1-3h; The annealing temperature is 250-300° C., and the annealing time is 0.5-2 hours.

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