A flexible pressure sensor based on multi-level structure carbon material and a preparation method thereof
By growing one-dimensional carbon nanotube coils on two-dimensional graphene sheets to form a multi-level structure, the problems of slow sensitivity and response speed of flexible pressure sensors are solved, achieving high sensitivity and fast response pressure detection.
Patent Information
- Application Number
- CN202410950593.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-16
- Publication Date
- 2025-11-28
- Estimated Expiration
- 2044-07-16
AI Technical Summary
Existing flexible piezoresistive pressure sensors suffer from complex manufacturing processes, low sensitivity, and slow response speed.
One-dimensional carbon nanotube coils were grown on two-dimensional graphene sheets using hydrothermal and catalytic chemical vapor deposition methods to form a multi-level structure. By combining reduced graphene oxide and carbon nanotube coils, the stacking problem between graphene sheets was solved, and the conductive network was enhanced.
The sensitivity and response speed of the flexible pressure sensor have been improved, making it suitable for pressure detection under both low and high pressure conditions, as well as for monitoring human physiological indicators and detecting human activities.
Smart Images
Figure CN118776714B_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the technical field of new materials and functional materials, and belongs to the technical field of sensors, and particularly relates to a flexible pressure sensor based on a multi-level structure carbon of reduced graphene oxide / carbon nanocoil and a preparation method thereof. BACKGROUND
[0002] In recent years, people pay more and more attention to health, which promotes the development of artificial intelligence, human-computer interaction, health monitoring, electronic skin and other technologies, and the research on flexible pressure sensors that can monitor human motion and human health is continuously deepened. The flexible piezoresistive pressure sensor is composed of three parts of electrodes, flexible substrate and pressure sensitive material, can convert mechanical information into resistance change, and has the advantages of light weight, low cost, simple manufacturing process, low energy consumption and simple signal acquisition mode. However, most of the piezoresistive pressure sensors reported have the problems of low sensitivity and slow response speed.
[0003] The unique spiral morphology of carbon nanocoil (CNCs) endows it with super elasticity, so that it can perceive pressure in a large stretching range. Graphene and its derivatives, such as graphene oxide and reduced graphene oxide, have large surface area-volume ratio and excellent electrical properties, and have been proved to be the best material for flexible sensors. However, the strong Π-Π bond between graphene sheets results in a huge van der Waals force that causes the stacking of the sheets, which affects the sensing performance of the flexible pressure sensor.
[0004] Through the above analysis, the problems and defects of the prior art are that most of the flexible piezoresistive pressure sensors have the problems of complex manufacturing process, low sensitivity and slow response speed. SUMMARY
[0005] In view of the problems in the prior art, the application provides a flexible pressure sensor based on a multi-level structure carbon material and a preparation method thereof. By using a hydrothermal method and a catalytic chemical vapor deposition method, one-dimensional carbon nanocoils are directly grown on two-dimensional graphene sheets to form a multi-level structure, thereby solving the problem of stacking between graphene sheets, and further preparing a porous flexible pressure sensor based on the multi-level structure carbon material to solve the technical problems of low sensitivity and slow response speed of the flexible pressure sensor.
[0006] To achieve the above purpose, the technical scheme adopted by the application is as follows:
[0007] A flexible pressure sensor based on a multi-level structure carbon material and a preparation method thereof, characterized by comprising the following steps:
[0008] S1, a graphene oxide aqueous dispersion slurry (purity 2wt%), polyvinylpyrrolidone and sodium cholate are added to deionized water in a certain proportion, shearing stirring 1h~2 h, ultrasonic treatment 30 min~1h, to obtain a uniformly dispersed GO solution. A certain proportion of nickel chloride hexahydrate, iron chloride hexahydrate and urea are added to the GO solution, shearing stirring 1h~2h, ultrasonic treatment 30 min~1h, transferred to a polytetrafluoroethylene hydrothermal reactor, 100 ℃~160 ℃ incubation for 6 h~12 h. After natural cooling, the obtained precipitate is washed with deionized water and alcohol for three times respectively, and freeze-dried to obtain a reduced graphene oxide powder loaded with a nickel-iron bimetallic catalyst precursor;
[0009] S2, the reduced graphene oxide powder loaded with a nickel-iron bimetallic catalyst precursor is laid in a quartz boat, placed in a tube furnace, and inert gas is introduced at a flow rate of 40sccm-60sccm. The reaction device is heated to 400℃~600℃, and annealing treatment is carried out for 2h~3h. Then hydrogen gas is introduced, and the temperature is further increased to 600~800 ℃. After the temperature is stabilized, the hydrogen gas is turned off, and a carbon source is introduced at a flow rate of 20 sccm~40 sccm. The reaction is carried out at 600~800 ℃ for 30 min~2h, and then the temperature is cooled to room temperature. A reduced graphene oxide / carbon nanocoil multi-level structure carbon material is obtained.
[0010] S3, the reduced graphene oxide / carbon nanocoil multi-level structure carbon material obtained is dispersed in deionized water, placed in a flexible porous foam material, and ultrasonic treatment is carried out for 30 min~2 h. After drying in an oven, the material is cut to a certain size, and upper and lower electrodes are installed. A flexible pressure sensor based on the reduced graphene oxide / carbon nanocoil multi-level structure carbon material is obtained.
[0011] Further, the mass ratio of the graphene oxide aqueous dispersion slurry (purity 2wt%), polyvinylpyrrolidone and sodium cholate in S1 is 100~200:1~10:1~10.
[0012] Further, the mass ratio of the nickel chloride hexahydrate, iron chloride hexahydrate and urea in S1 is 1~5:1~20:40~80.
[0013] Further, the filling ratio of the mixed solution in S1 in the polytetrafluoroethylene container is 50%~80%.
[0014] Further, the K value of the polyvinylpyrrolidone in S1 is 30, i.e. PVP K30.
[0015] Further, the inert gas in S2 is nitrogen, argon, etc. The gas needs to be introduced throughout the reaction process from the beginning of heating to cooling.
[0016] Further, the carbon source in step S2 is acetylene.
[0017] Further, the first heating rate of the heating reaction device in step S2 is 6-9℃ / min.
[0018] Further, the flexible porous foam material in step S3 includes polyurethane foam, PDMS foam, etc.
[0019] The application further discloses a flexible pressure sensor prepared by the preparation method of the flexible pressure sensor based on the multi-level structure carbon material.
[0020] In combination with the above technical solutions and the solved technical problems, the application has the following advantages and positive effects:
[0021] First, the application provides a flexible pressure sensor based on a multi-level structure carbon material and a preparation method thereof. By using a hydrothermal method and a catalytic chemical vapor deposition method, one-dimensional carbon nanocoils are directly grown on two-dimensional graphene sheets to form a multi-level structure, thereby solving the stacking problem between graphene sheet layers. The carbon nanocoils and graphene oxide are combined, on one hand, the carbon nanocoils grown in situ from catalyst particles attached to the surface of graphene oxide can support between graphene sheet layers to reduce the agglomeration of graphene; on the other hand, the conductive network composed of two-dimensional reduced graphene oxide and one-dimensional spiral carbon nanofibers can increase the conductive path, and the use of the carbon material with multiple structures is proved to effectively improve the sensing performance of the multifunctional sensor. By preparing the flexible pressure sensor based on the multi-level structure carbon material, the sensitivity of the flexible pressure sensor is improved.
[0022] Second, the sodium cholate used in the application helps the dispersion of graphene oxide in water.
[0023] The mass ratio of the nickel chloride hexahydrate, the iron chloride hexahydrate and the urea used in the application is 1-5:1-20:40-80, under which the particle size of the nanometer nickel-iron alloy catalyst particles is uniform, and the bimetallic alloy catalyst is beneficial to the low-temperature growth of the carbon nanocoil.
[0024] The PVP K30 used in the application has a small molecular weight and a small viscosity, which can not only uniformly disperse and uniformly coat the graphene oxide sheets in water, but also complex metal ions and uniformly load nanometer nickel-iron bimetallic catalyst particles on the graphene oxide.
[0025] Inert gas is introduced throughout the process of the application, which effectively prevents the oxidation of the material.
[0026] The carbon nanocoil grown by using acetylene as the carbon source has a higher yield, a larger coil fiber diameter and a higher helicity.
[0027] The first temperature rising speed of the heating reaction device is 6-9 DEG C / min, and the purpose of the first temperature rising is annealing, so as to obtain the nano nickel-iron alloy catalyst particles; if the temperature rising speed is too fast, the morphology of the nano nickel-iron alloy catalyst particles is affected, and then the growth of the subsequent carbon nanocoil is affected. The nano nickel-iron alloy catalyst particles obtained by pyrolysis at the speed have uniform particle size distribution, and the grown carbon nanocoil has high purity.
[0028] The porous foam material is adopted, the multi-stage carbon material is attached to the surface of the porous foam frame, more effective contact sites can be provided for the sensor, and therefore large sensitivity and fast response speed are provided
[0029] Thirdly, the flexible pressure sensor of the multi-stage structure carbon material prepared in the application has excellent sensitivity (393 kPa -1 , 0-50 kPa) under low pressure conditions (0-50 kPa) and high pressure application (200 kPa-400 kPa), and is suitable for a large number of pressure detection work scenes, such as human physiological index monitoring and human activity detection.
[0030] The flexible pressure sensor of the multi-stage structure carbon material prepared in the application has simple process, low production cost, high efficiency, and is easy to realize continuous and large-scale production. BRIEF DESCRIPTION OF DRAWINGS
[0031] In order to more clearly illustrate the technical solutions of the embodiments of the application, the drawings needed to be used in the embodiments of the application will be briefly introduced as follows. Obviously, the drawings described below are only some embodiments of the application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of these drawings.
[0032] Figure 1 The process flow diagram for preparing the multi-stage structure carbon material reduced graphene oxide / carbon nanocoil of the application is shown in the figure.
[0033] Figure 2 The SEM image of the multi-stage structure carbon material reduced graphene oxide / carbon nanocoil prepared in Example 1 is shown in the figure.
[0034] Figure 3 The SEM image of the multi-stage structure carbon material reduced graphene oxide / carbon nanocoil prepared in Comparative Example 1 is shown in the figure.
[0035] Figure 4 The SEM image of the multi-stage structure carbon material reduced graphene oxide / carbon nanocoil prepared in Comparative Example 2 is shown in the figure.
[0036] Figure 5 The physical picture of the flexible pressure sensor based on the multi-stage structure carbon material prepared in Example 1 is shown in the figure.
[0037] Figure 6 Sensitivity comparison chart of Example 1, Comparative Example 3 and Comparative Example 4;
[0038] Figure 7 Sensitivity test chart of the flexible pressure sensor prepared in Example 1;
[0039] Figure 8 Cycle response test chart of the flexible pressure sensor prepared in Example 1;
[0040] Figure 9 I-V curve chart of the flexible pressure sensor prepared in Example 1;
[0041] Figure 10 Hysteresis curve chart of the flexible pressure sensor prepared in Example 1; DETAILED DESCRIPTION
[0042] The principles and features of the present application are described below in conjunction with the accompanying drawings, and the examples are only used to explain the present application and are not intended to limit the scope of the present application. The specific conditions are not specified in the examples, and the conventional conditions or the conditions recommended by the manufacturer are used. The reagents or instruments used are not specified by the manufacturer, and are conventional products that can be purchased on the market.
[0043] In view of the problems in the prior art, the present application provides a design of a carbon nanotube-based flexible pressure-sensitive film material with a multi-modal pore distribution and a preparation method thereof.
[0044] Example 1:
[0045] A preparation method of a flexible pressure sensor based on a multi-level structure carbon material, comprising the following steps:
[0046] S1, add graphene oxide water-based dispersion slurry (purity 2wt%), polyvinylpyrrolidone and sodium cholate to deionized water in a mass ratio of 200:1:1, shear stirring for 1h, ultrasonic treatment for 30min, to obtain a uniformly dispersed GO solution. Add nickel chloride hexahydrate, iron chloride hexahydrate and urea in a molar ratio of 1:2:60 to the GO solution, shear stirring for 1h, ultrasonic treatment for 30min, transfer to a polytetrafluoroethylene hydrothermal reactor, and react at 120℃ for 12h. After natural cooling, the obtained precipitate is washed with deionized water and alcohol for three times respectively, and freeze-dried to obtain a reduced graphene oxide powder loaded with a nickel-iron bimetallic catalyst precursor;
[0047] S2, the reduced graphene oxide powder loaded with nickel-iron bimetallic catalyst precursor is laid in a quartz boat, placed in a tube furnace, 40 sccm of inert gas is introduced, the reaction device is heated to 500 DEG C, annealing treatment is carried out for 2h, then hydrogen is introduced, and heating is continued to 650 DEG C. After the temperature is stable, the hydrogen is closed, acetylene is introduced, the gas flow is set to 30 sccm, 650 DEG C is reacted for 30 min, and then cooled to room temperature, to obtain reduced graphene oxide / carbon nanocoil multi-level structure carbon material;
[0048] The prepared reduced graphene oxide / carbon nanocoil multi-level structure carbon material is detected by scanning electron microscope, and the result is shown in Figure 2 As shown, the surface of the reduced graphene oxide sheet layer is covered by the carbon nanocoil, and the carbon nanocoil extends outwardly based on the surface of the reduced graphene oxide sheet layer.
[0049] S3, the obtained reduced graphene oxide / carbon nanocoil multi-level structure carbon material is dispersed in deionized water, placed in a carbon nanotube PDMS porous foam, ultrasonic treated for 30 min, dried in an oven, cut to a certain size, and then equipped with upper and lower electrodes to obtain a flexible pressure sensor based on the reduced graphene oxide / carbon nanocoil multi-level structure carbon material.
[0050] The actual picture of the prepared flexible pressure sensor based on the reduced graphene oxide / carbon nanocoil multi-level structure carbon material is shown in Figure 5 .
[0051] Example 2:
[0052] Compared with example 1, the difference of the embodiment of the application lies in that in step 3, the obtained reduced graphene oxide / carbon nanocoil multi-level structure carbon material is dispersed in deionized water, placed in a carbon nanotube PDMS porous foam, and ultrasonic treated for 60 min; that is, the ultrasonic treatment time is controlled to be 60 min, and the remaining steps are the same as those in example 1.
[0053] Example 3:
[0054] Compared with example 1, the difference of the embodiment of the application lies in that in step 3, the obtained reduced graphene oxide / carbon nanocoil multi-level structure carbon material is dispersed in deionized water, placed in a carbon nanotube PDMS porous foam, and ultrasonic treated for 90 min; that is, the ultrasonic treatment time is controlled to be 90 min, and the remaining steps are the same as those in example 1.
[0055] Comparative example 1:
[0056] A preparation method of a multi-level structure carbon material, comprising the following steps:
[0057] S1. Graphene oxide aqueous dispersion slurry (2wt% purity), polyvinylpyrrolidone, and sodium cholate were added to deionized water at a mass ratio of 200:1:1. The mixture was sheared and stirred for 1 hour, then sonicated for 30 minutes to obtain a uniformly dispersed GO solution. Nickel chloride hexahydrate and urea were added to the GO solution at a molar ratio of 1:60. The mixture was sheared and stirred for 1 hour, then sonicated for 30 minutes. The solution was then transferred to a polytetrafluoroethylene hydrothermal reactor and reacted at 120 °C for 10 hours. After natural cooling, the resulting precipitate was washed three times with deionized water and alcohol, respectively, and then freeze-dried to obtain reduced graphene oxide powder supported on a metal catalyst precursor.
[0058] S2. Reduced graphene oxide powder with a supported metal catalyst precursor was spread evenly in a quartz boat and placed in a tube furnace. An inert gas flow of 40 sccm was introduced, and the reaction apparatus was heated to 500°C. After annealing for 2 hours, hydrogen gas was introduced, and the temperature was further increased to 650°C. After the temperature stabilized, the hydrogen gas was turned off, and a carbon source was introduced at a flow rate of 30 sccm. The reaction was carried out at 650°C for 30 minutes, and then cooled to room temperature to obtain a multi-level carbon material with reduced graphene oxide / carbon nanocoil structure.
[0059] The prepared reduced graphene oxide / carbon nanocoil hierarchical carbon material was examined by scanning electron microscopy, and the results are as follows: Figure 3 As shown. Compared with Example 1, the multi-level carbon material fibers prepared in Comparative Example 1 have poor diameter uniformity, highlighting the necessity of using a nickel-iron bimetallic catalyst to catalyze the growth of carbon nanotube coils through acetylene cracking.
[0060] Comparative Example 2:
[0061] A method for preparing carbon materials based on hierarchical structures includes the following steps:
[0062] S1. Graphene oxide aqueous dispersion slurry (2wt% purity), polyvinylpyrrolidone, and sodium cholate were added to deionized water at a mass ratio of 200:1:1. The mixture was sheared and stirred for 1 hour, then sonicated for 30 minutes to obtain a uniformly dispersed GO solution. Ferric chloride hexahydrate and urea were added to the GO solution at a molar ratio of 1:60. The mixture was sheared and stirred for 1 hour, then sonicated for 30 minutes. The solution was then transferred to a polytetrafluoroethylene hydrothermal reactor and reacted at 120 °C for 10 hours. After natural cooling, the resulting precipitate was washed three times with deionized water and alcohol, respectively, and then freeze-dried to obtain reduced graphene oxide powder supported on a metal catalyst precursor.
[0063] S2, the reduced graphene oxide powder loaded with metal catalyst precursor was laid in a quartz boat in a tube furnace, 40 sccm of inert gas was introduced, the reaction device was heated to 500°C, annealing treatment was performed for 2h, then hydrogen was introduced, and the temperature was continuously increased to 650°C. After the temperature was stable, the hydrogen was closed, ethanol was introduced, the gas flow was set to 30 sccm, and 650°C was reacted for 30 min, and then cooled to room temperature to obtain reduced graphene oxide / carbon nanocoil multi-level structure carbon material.
[0064] The prepared reduced graphene oxide / carbon nanocoil multi-level structure carbon material was detected by scanning electron microscope, and the results are shown in Figure 4 Compared with Example 1, the multi-level structure carbon material carbon nanocoil prepared by using ethanol in Comparative Example 2 has low yield and poor helicity, which reflects the necessity of using acetylene as a carbon source.
[0065] Comparative Example 3:
[0066] S1, the carbon nanotube PDMS porous foam was equipped with upper and lower electrodes to obtain a flexible pressure sensor based on the carbon nanotube PDMS porous foam.
[0067] Comparative Example 4:
[0068] S1, the obtained reduced graphene oxide was dispersed in deionized water, put into the carbon nanotube PDMS porous foam, ultrasonic treatment for 30 min, placed in an oven for drying, cut to a certain size, and equipped with upper and lower electrodes to obtain a flexible pressure sensor based on reduced graphene oxide.
[0069] Test the current change rate of the flexible pressure sensors prepared in Comparative Example 1, Comparative Example 2 and Example 1 in the pressure range of 0~400 kPa, as shown in Figure 6 The addition of the sheet structure with smooth surface only increases the contact mode of the limited conductive network. Relatively, the carbon nanocoil uniformly covered on the surface of the reduced graphene oxide / carbon nanocoil multi-level structure carbon material itself is beneficial to the response of the pressure sensor. The combination of the spring structure and the sheet structure of graphene prevents the stacking of graphene sheets while providing a large number of new conductive paths for the sensor, effectively improving the sensitivity of the sensor. This shows the necessity of using reduced graphene oxide / carbon nanocoil multi-level structure carbon material to improve the sensitivity of the sensor.
[0070] The carbon nanotube-based flexible pressure-sensitive film material with multi-modal pore distribution prepared in Example 1 was used for experiments.
[0071] 1. Sensitivity test
[0072] The specific testing method is as follows: Pressure is applied to the sensor using a universal pressure testing machine, and IT data is obtained using a KE2401 machine. The slope of the rate of change of the current signal relative to the applied external pressure is defined as the sensor's sensitivity. The sensitivity of the resistive flexible pressure sensor is calculated using the following formula:
[0073] ,
[0074] In the formula, S represents the sensitivity of the sensor. This refers to the relative change in current of the sensor. This represents the input pressure change. The test results are as follows: Figure 7 As shown, the sensor exhibits relatively high sensitivity (up to 393) over a wide pressure sensing range (0~400 kPa). The curve can be divided into four linear regions, with a sensitivity of 393 kPa in the pressure range of 0 to 50 kPa. -1 The sensitivity is 237 kPa in the range of 50 to 100 kPa. -1 The sensitivity is 158 kPa in the range of 100 to 200 kPa. -1 , and 98 kPa -1 Within the range of 200 to 400 kPa.
[0075] 2. Cyclic response test
[0076] Cyclic repeatability testing refers to comparing the consistency of the resistive response of a flexible pressure sensor to pressure with its initial detection performance after hundreds or thousands of pressure cycles within the same test environment and continuous time. The specific test method is as follows: apply a pressure of 100 kPa to the sensor, cycle 5000 times, obtain IT data using a KE2401 testing machine, obtain the current change rate, and plot the cyclic response test curve. Figure 8 The sensor obtained by this invention has excellent stability, and it can exhibit good pressure response during nearly 5,000 cycles.
[0077] 3. IV curve test
[0078] The specific testing method is as follows: Apply force to the sensor to achieve pressures of 0 kPa, 25 kPa, 50 kPa, 100 kPa, 200 kPa, and 400 kPa, keep the pressure constant, and use a KE2401 to test the sensor's current-voltage curves under different pressures, such as... Figure 9 The sensor obtained by this invention exhibits linear changes in its IV curve under different pressure conditions, and its resistance value shows good ohmic characteristics.
[0079] 4. Hysteresis Curve Test
[0080] The specific test method is: by comparing the I-T curve of the sensor through forward output and reverse output, when the two cannot be completely repeated, it indicates that the sensor has hysteresis, and the hysteresis degree can be represented by the ratio of the maximum hysteresis error ΔI and the maximum resistance value Imax in the test range, the sensor is subjected to pressure from 0-300 kPa by the press, the I-T data is obtained by using KE2401, then the tension machine is used to apply pressure from 300-0 kPa, the I-T data is obtained by using KE2401, and then the maximum hysteresis is obtained, and the result is shown in Figure 10 The maximum hysteresis obtained by test is 0.1, which indicates that the sensor has low delay and responds to pressure in time.
[0081] The above only describes the preferred embodiments of the present application, and is not used to limit the present application, any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.
Claims
1. A method for preparing a flexible pressure sensor based on a multi-stage structure carbon material, characterized in that, Comprising the following steps: S1, the graphene oxide water-based dispersion slurry, purity is 2wt%, polyvinylpyrrolidone and sodium cholate is added to deionized water in a certain proportion, shearing stirring 1h~2h, ultrasonic treatment 30min~1h, get uniform dispersion of GO solution, to the GO solution is added in a certain proportion of nickel chloride hexahydrate, iron chloride hexahydrate and urea, shearing stirring 1h~2h, ultrasonic treatment 30min~1h, transfer to polytetrafluoroethylene hydrothermal reactor, 100℃~160℃ heat preservation reaction 6h~12h, natural cooling, the obtained precipitate is washed with deionized water and alcohol respectively three times, freeze drying, get the reduced graphene oxide powder of nickel iron bimetallic catalyst precursor; S2, the reduced graphene oxide powder of nickel iron bimetallic catalyst precursor is laid in quartz boat, placed in tube furnace, 40sccm-60sccm of inert gas is imported, heating reaction device to 400℃~600℃, annealing treatment 2h~3h, then hydrogen is imported, continue to heat to 600~800℃, after the temperature is stable, close the hydrogen, import carbon source, gas flow is set to 20sccm~40sccm, 600~800℃ reaction 30min~2h, then cool to room temperature, get reduced graphene oxide / carbon nanocoil multi-level structure carbon material; S3, the reduced graphene oxide / carbon nanocoil multi-level structure carbon material obtained is dispersed in deionized water, put into flexible porous foam material, ultrasonic treatment 30min~2h, put into oven and dry, cut to a certain size, install upper and lower electrodes to get flexible pressure sensor based on reduced graphene oxide / carbon nanocoil multi-level structure carbon material.
2. The method for producing a flexible pressure sensor based on a multi-stage structure carbon material according to claim 1, characterized by, The graphene oxide water-based dispersion slurry in S1, the purity is 2wt%, the mass ratio of polyvinylpyrrolidone and sodium cholate is 100~200:1~10:1~10.
3. The method for manufacturing a flexible pressure sensor based on a multi-stage structure carbon material according to claim 1, wherein The mass ratio of nickel chloride hexahydrate, iron chloride hexahydrate and urea in S1 is 1~5:1~20:40~80.
4. The method for manufacturing a flexible pressure sensor based on a multi-stage structure carbon material according to claim 1, wherein The filling ratio of GO solution in S1 in polytetrafluoroethylene hydrothermal reactor is 50%~80%.
5. The method for manufacturing a flexible pressure sensor based on a multi-stage structure carbon material according to claim 1, wherein The K value of polyvinylpyrrolidone in S1 is 30, namely PVP K30.
6. The method for manufacturing a flexible pressure sensor based on a multi-stage structure carbon material according to claim 1, wherein The inert gas in S2 is nitrogen, argon, which needs to be imported from the beginning of heating to the whole process of cooling.
7. The method for manufacturing a flexible pressure sensor based on a multi-stage structure carbon material according to claim 1, wherein The carbon source in S2 is acetylene.
8. The method for manufacturing a flexible pressure sensor based on a multi-stage structure carbon material according to claim 1, wherein The first heating speed of heating reaction device in S2 is 6℃~9℃ / min.
9. The method of claim 1, wherein the method further comprises the steps of: coating the carbon material with a polymer; and drying the carbon material. The flexible porous foam material in S3 includes polyurethane foam, PDMS foam.
10. The flexible pressure sensor based on multi-level structure carbon material prepared by the preparation method of claim 1-8.
11. The application of the preparation method of flexible pressure sensor based on multi-level structure carbon material in claim 9 in wearable electronic equipment.