Triboelectric nanogenerator based on tin tetrachloride / modified polyvinyl alcohol film and preparation method and system

Abstract

The present invention belongs to the technical field of friction nanogenerators, and specifically relates to a friction nanogenerator based on tin tetrachloride / modified polyvinyl alcohol film, a preparation method and an application thereof. The nanogenerator is composed of a contact separation mode part and a lateral sliding mode part, with SnCl4-modified PVA film and a PTFE spray-coated film on a metal mesh substrate as a power generation layer. The contact separation mode part and the lateral sliding mode part work together to convert mechanical energy in the environment into electrical energy. The nanogenerator is applied to a friction power generation motion detection system, and the friction power generation motion detection system can be used to detect motion characteristics at different joints of the human body. The friction power generation motion detection sensor proposed by the present invention has a faster response speed and better motion intensity resolution. The friction nanogenerator converts external mechanical stimulation into electrical pulses of corresponding intensity, does not require battery power supply, and avoids the sensor's dependence on battery power supply.

Description

Technical Field

[0001] The invention belongs to the technical field of friction nanogenerators, and in particular relates to a friction nanogenerator based on tin tetrachloride / modified polyvinyl alcohol film and a preparation method and application thereof. Background Art

[0002] With the development of flexible wearable electronic devices, wireless sensor nodes and implantable devices, there is a great demand for energy harvesting devices that can provide milliwatt / microwatt energy output in many fields. In recent years, various energy harvesting technologies have emerged. The industry is developing smaller and more suitable energy harvesting devices, many of which use mechanical motion to generate electrical energy. For example, electrostatic electret, piezoelectric power generation, electromagnetic power generation and triboelectric power generation. In recent years, the triboelectric nanogenerator (TENG), which is based on the combination of triboelectric effect and electrostatic induction, has been favored because of its small size and great potential to convert mechanical energy such as motion into electrical energy output.

[0003] As an energy generating unit, the friction nanogenerator has a charge transfer between two friction material layers with different friction polarities in its internal circuit due to the frictional electrification effect, which forms a potential difference between the two. In the external circuit, electrons flow between two electrodes attached to the back of the friction material layer or between the electrode and the ground under the drive of the potential difference, thereby balancing the potential difference. The power source of the friction nanogenerator can be the wind, water, waves and other large energy sources that are already known to people, or the often ignored random environmental energy such as human walking, body shaking, hand touch, falling raindrops, etc., or the rotation of wheels, the roar of machines, etc.

[0004] There are four basic working modes of the friction nanogenerator, an energy harvester based on triboelectricity: vertical contact-separation mode, lateral sliding mode, single electrode mode, and independent layer mode. The friction nanogenerator has the characteristics of high energy conversion efficiency, easy manufacturing, low cost, and high power density. Despite this, the friction nanogenerator also faces technical challenges. Therefore, it is necessary to continuously improve the structural design of the friction nanogenerator, realize the coordination of multiple working modes, significantly improve the output performance of the friction nanogenerator, and apply it more widely to practical scenarios, including large-scale LED array lighting, self-powered load devices, motion monitoring, etc. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present invention provides a friction nanogenerator based on tin tetrachloride / modified polyvinyl alcohol film, a preparation method and an application thereof, utilizing SnCl4-modified PVA film and a PTFE spray-coated film on a metal mesh substrate as the power generation layer of the friction nanogenerator, integrating the contact separation mode and the lateral sliding mode, so that the TENG can work synergistically in these two modes at the same time, converting the mechanical energy in the environment into electrical energy; further, a friction electric sensor is designed based on the contact separation mode, and a targeted design is performed according to the detection characteristics of different joints, thereby realizing accurate detection of finger bending, wrist bending, elbow movement, knee bending and stepping behavior.

[0006] In order to achieve the above-mentioned purpose, the present invention adopts the following technical scheme: a friction nanogenerator based on SnCl4 modified PVA film, characterized in that: the nanogenerator consists of a contact separation mode part and a lateral sliding mode part, with SnCl4 modified PVA film and PTFE spray-coated film on a metal mesh substrate as the power generation layer, and the contact separation mode part and the lateral sliding mode part work together to convert mechanical energy in the environment into electrical energy.

[0007] According to a further technical solution of the present invention, the contact-separation mode is, from top to bottom, a support plate, a sponge buffer layer, a metal mesh electrode, a PTFE spray layer, a PVA-SnCl4 modified film, a metal foil electrode, a sponge buffer layer and a support plate.

[0008] According to a further technical solution of the present invention, the lateral sliding modes are provided with two groups, symmetrically distributed on both sides of the contact and separation mode part, and each group of lateral sliding modes is provided with four groups of identical power generation modules;

[0009] Alternatively, the power generation module comprises, from the inside to the outside, a support plate, a sponge buffer layer, a metal foil electrode, a PVA-SnCl4 modified film, a PTFE spray layer, a metal foil electrode and a support plate.

[0010] According to a further technical solution of the present invention, the distance between the PTFE spray layer and the PVA-SnCl4 modified film in the contact separation mode is equal to the distance between adjacent power generation modules in the lateral sliding mode;

[0011] Or, the electrodes corresponding to the bottom layer of the PVA-SnCl4 modified film are connected to the same port, and the electrodes corresponding to the bottom layer of the PTFE spray coating film are connected to another port, and the two ports are two input ends of the rectifier and filter circuit respectively;

[0012] Alternatively, the output electrical signal of the friction nanogenerator is rectified and filtered and then supplied to the outside in the form of direct current, the DC voltage in the contact and separation mode is 131.63V, and the DC voltage in the lateral sliding mode is 25.76V.

[0013] According to a further technical solution of the present invention, the material of the metal mesh electrode and the metal foil electrode is one of Al, Cu, Ni and Ag, the thickness of the metal mesh electrode is 100 microns, and the thickness of the metal foil electrode is 100 microns;

[0014] Alternatively, the support board is one of a basswood board and a birch board, and has a thickness of 2 mm.

[0015] The present invention also includes a method for preparing a triboelectric nanogenerator based on SnCl4-modified PVA film.

[0016] (1) Preparation of PVA-SnCl4 modified film;

[0017] (2) preparing a PTFE spray film on a metal mesh substrate;

[0018] (3) Preparation of contact-separation mode friction nanogenerator;

[0019] (4) Preparation of a friction nanogenerator in lateral sliding mode;

[0020] (5) Combining the friction nanogenerator in contact-separation mode and the friction nanogenerator in lateral sliding mode.

[0021] A further technical solution of the present invention is:

[0022] The specific steps of step (1) include:

[0023] (1-1) A 0.05 mol / L SnCl4 solution was prepared in 20 mL of deionized water, and 3 g of PVA particles were added. The mixture was placed in a water bath at 85 °C and magnetically stirred for 3 h.

[0024] (1-2) Spin coating the PVA-SnCl4 viscous solution obtained in step (1-1) on the surface of the metal foil electrode, rotating at a speed of 1070 rpm for 18 s in the first stage and rotating at a speed of 2510 rpm for 60 s in the second stage, and finally placing the resultant in a vacuum drying oven at 50°C for 3 hours;

[0025] Or, the specific steps of step (2) include:

[0026] Ultrasonic oscillation was performed on a PTFE emulsion with a solid content of 60% for 10 minutes, and the PTFE emulsion was evenly sprayed on the surface of the metal mesh electrode three times with a spray gun, and the resultant was placed in a drying oven at 50°C for 3 hours;

[0027] Alternatively, the specific steps of step (3) include:

[0028] A basswood board is used as a support board, and a double-sided sponge adhesive is attached to the basswood board as a buffer layer. Two identical boards are prepared. Take one of the boards, and the PVA-SnCl4 modified film prepared on the surface of the metal foil in step (1) is attached to the surface of the sponge buffer layer as a whole, and a wire is led out from the lower surface of the metal foil to serve as a movable electrode; the PTFE spray coating of the metal mesh substrate prepared in step (2) is attached to the surface of the sponge buffer layer of the other board, and a wire is led out from the bottom of the metal mesh to serve as a fixed electrode;

[0029] Alternatively, the specific steps of step (4) include:

[0030] The lateral sliding modes are provided with two groups, and the preparation method of each group of lateral sliding modes is the same, including:

[0031] A basswood board is used as a support board, and a double-sided sponge adhesive is attached to the basswood board as a buffer layer. Two identical boards are prepared, and the surface of the sponge buffer layer of one board is attached with a PVA-SnCl4 modified film having a metal electrode substrate prepared on the surface of the metal foil in step (1), and at the same time, the PVA-SnCl4 modified film electrode is connected in parallel from the lower surface of the metal foil, and a wire is led out, and this part is used as a fixed electrode; the surface of the sponge buffer layer of the other board is attached with a PTFE spray layer prepared on the metal mesh substrate in step (2), and parallel connections are made from the bottom of the metal mesh, and then a wire is led out, and this part is used as a fixed electrode;

[0032] Alternatively, the specific steps of step (5) include:

[0033] Two sets of lateral sliding modes are symmetrically fixed on both sides of the contact-separation mode part.

[0034] The present invention also includes the application of a friction nanogenerator based on SnCl4 modified PVA film, wherein the nanogenerator has a structure of a contact separation mode portion.

[0035] The nanogenerator is applied to a friction power generation motion detection system, and the friction power generation motion detection system can be used to detect motion characteristics at different joints of the human body.

[0036] According to a further technical solution of the present invention, the system comprises a triboelectric sensor made of a nanogenerator, a WIFI data transmission module, a single-chip computer data acquisition module and a host computer data display module;

[0037] Alternatively, the support plate, sponge buffer layer, metal mesh electrode, PTFE spray layer, PVA-SnCl4 modified film, and metal foil electrode of the contact-separation mode are all provided with a protruding portion with a thickness of 0.3 mm.

[0038] A further technical solution of the present invention is:

[0039] The voltage across the triboelectric sensor of the bent finger obtained in the experiment is connected to the ADC data acquisition port of the microcontroller and the WIFI module can be used to observe the voltage pulse waveform of the triboelectric sensor under the stimulation of finger movement in real time on the host computer; the hand posture can be resolved by collaboratively analyzing the five signals.

[0040] The advantages of the friction nanogenerator based on SnCl4 modified PVA film and its preparation method and application in the present invention are as follows:

[0041] (1) The PVA-SnCl4 / PTFE contact-separation mode configuration is used to design a triboelectric motion sensor to achieve self-driving of the sensing system. The core part of the PVA-SnCl4 / PTFE triboelectric nanogenerator is the internal protrusion, which has a size of 1cm×2cm×0.3cm. Two pairs of protrusions are arranged side by side in the elbow joint and knee joint sensors. This type of sensor can generate corresponding pulse voltage and current by itself under external mechanical stimulation, thus eliminating the need for external power supply equipment.

[0042] (2) Compared with ordinary motion detection sensors, the triboelectric motion sensor designed based on the PVA-SnCl4 / PTFE contact-separation mode configuration has a faster response speed to external mechanical stimulation (the response speed to finger bending is 12ms), which can meet the requirements of high response accuracy in the fields of robotic training detection and body rehabilitation monitoring.

[0043] (3) The voltage at both ends of the finger bending sensor is connected to the ADC data acquisition port of the microcontroller and the WIFI module can be used to observe the voltage pulse waveform of the triboelectric sensor under the stimulation of finger movement in real time on the host computer. The hand posture can be analyzed by collaborative analysis of the five signals. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 (a) is a schematic diagram of the structure of a contact-separation-lateral sliding cooperative mode friction nanogenerator according to an embodiment of the present invention;

[0045] (b) is a schematic diagram of the fixed electrode structure of the contact-separation-lateral sliding cooperative mode friction nanogenerator according to an embodiment of the present invention;

[0046] (c) is a schematic diagram of the structure of the moving electrode portion of the contact separation-lateral sliding cooperative mode friction nanogenerator according to an embodiment of the present invention;

[0047] Figure 2 (a) is a schematic diagram of the operating mechanism of the contact separation mode of an embodiment of the present invention;

[0048] (b) is a schematic diagram of the operation mechanism of the lateral sliding mode according to an embodiment of the present invention;

[0049] Figure 3 This is a circuit distribution diagram of a signal processing circuit of a friction nanogenerator in a contact separation-lateral sliding cooperative mode according to an embodiment of the present invention;

[0050] Figure 4 (a) is a photo of a contact-separation-lateral sliding cooperative mode friction nanogenerator according to an embodiment of the present invention;

[0051] (b) is a graph showing the relationship between output voltage / current and load resistance according to an embodiment of the present invention;

[0052] Figure 5 This is a scanning electron microscope image of the PVA-SnCl4 modified film of Example (a) of the present invention;

[0053] (b) Scanning electron micrograph of the PTFE spray coating material on the copper mesh substrate;

[0054] Figure 6 (a) is a diagram of a finger bending detection sensor made based on a contact-separation mode friction nanogenerator according to an embodiment of the present invention;

[0055] (b) Voltage output characteristic diagram of the finger bending detection sensor at different bending degrees at a bending frequency of 1 Hz;

[0056] Figure 7 This is a response time curve of the finger bending detection sensor according to an embodiment of the present invention at a bending frequency of 1 Hz and a bending degree of 45°;

[0057] Figure 8 This is a diagram of a triboelectric sensor for detecting stepping behavior made based on a contact-separation mode triboelectric nanogenerator according to an embodiment of the present invention;

[0058] Fig. 9 (a) is a voltage curve diagram of the pedaling behavior detection sensor according to an embodiment of the present invention in response to different pedaling conditions;

[0059] (b) is a response time curve of the stepping behavior detection sensor according to an embodiment of the present invention under normal walking conditions;

[0060] Fig.10 (a) is a physical diagram of the integrated five-finger bending detection sensor according to an embodiment of the present invention;

[0061] (b) is a unified real-time display of five signals implemented by a host computer written in Labview in an embodiment of the present invention. DETAILED DESCRIPTION

[0062] The specific implementation manner will be further described below in conjunction with the accompanying drawings.

[0063] Embodiment 1:

[0064] Triboelectric nanogenerator based on SnCl4 modified PVA film,

[0065] The contact separation-lateral sliding cooperative mode friction nanogenerator is formed by integrating the contact separation mode friction nanogenerator and the lateral sliding mode friction nanogenerator. The contact separation mode friction nanogenerator requires two modules: a basswood board is used as a support board, and a sponge double-sided adhesive is attached to the basswood board as a buffer layer. Take one of the modules, and attach the PVA-SnCl4 modified film prepared on the surface of the copper foil as a whole to the surface of the sponge buffer layer, and lead out a wire from the lower surface of the copper foil. This part is used as a movable electrode; the PTFE spray coating of the copper mesh substrate is attached to the surface of the sponge buffer layer of the other module, and a wire is led out from the bottom of the copper mesh. This part is used as a fixed electrode; the lateral sliding mode friction nanogenerator requires the preparation of four modules: a basswood board is used as a support board, and a sponge double-sided adhesive is attached to the basswood board as a buffer layer. Take two of the modules, and attach the PVA-SnCl4 modified film prepared on the surface of the copper foil as a whole to the surface of the sponge buffer layer. 4 The modified film is divided into four small pieces and pasted on the surface of the sponge buffer layer. At the same time, the four small pieces are connected in parallel from the lower surface of the copper foil, and then a wire is led out. This part is used as a fixed electrode; the PTFE spray layer of the aforementioned copper mesh substrate is pasted on the surface of the sponge buffer layer of the other two pieces, which are also four small pieces. Then they are connected in parallel from the bottom of the copper mesh, and then a wire is led out. This part is used as a fixed electrode; the spacing between the power generation layers in the contact separation mode part is the same as the spacing distance between the four electrodes in the lateral sliding mode part; the four small modules in each division of the lateral sliding mode TENG are connected in parallel at the bottom of the electrode to reduce the output port and reduce current loss; the contact separation-lateral sliding cooperative mode friction nanogenerator can generate pulse voltage during reciprocating motion.

[0066] The principle of improving the power generation capacity of the SnCl4-modified PVA film is as follows: the surface of the pure PVA film is very smooth, and its triboelectric power generation capacity is relatively unsatisfactory; after being modified by SnCl4, a rough microstructure can be formed on the surface of the PVA film, thereby improving the triboelectric performance;

[0067] Due to its own woven structure, the metal mesh electrode will dry into a PTFE film with a regular convex structure on its surface after spraying PTFE emulsion, which increases the roughness of the PTFE film and is beneficial to improving the triboelectric performance.

[0068] Figure 4 (a) is a real-life photo of a friction nanogenerator in the contact-separation-lateral sliding cooperative mode. In the experiment, the reciprocating motion of a linear motor is used to drive the operation of the device.

[0069] The output signal of the contact separation-lateral sliding cooperative mode friction nanogenerator can be processed by a rectification and filtering circuit to supply power to the outside. Figure 4(b) is the test result diagram of the relationship between output voltage / current and load resistance;

[0070] During the reciprocating motion of the contact-separation-lateral sliding cooperative mode friction nanogenerator, the contact-separation mode part can generate a large pulse voltage in one cycle; the lateral sliding mode part can generate four small pulse voltages in one cycle, and the pulse voltage of this part has a sinusoidal wave form as a whole.

[0071] The material of the generator metal electrode is one of Al, Cu, Ni and Ag, the material of the sensor metal electrode is one of Au, Ag, Cu, Al and Ni, the thickness of the sensor metal mesh electrode is 100 microns, and the thickness of the generator metal foil electrode is 100 microns.

[0072] The average molecular weight of the PVA particles is 27,000, and the solid content of the PTFE emulsion is 60%.

[0073] Figure 5 Scanning electron microscope images of the PTFE spray coating material of the PVA-SnCl4 modified film and the copper mesh substrate of the present invention;

[0074] The principle of improving the power generation capacity of the SnCl4-modified PVA film is as follows: the surface of the pure PVA film is very smooth, and its triboelectric power generation capacity is relatively unsatisfactory; after being modified by SnCl4, a rough microstructure can be formed on the surface of the PVA film, thereby improving the triboelectric performance;

[0075] Due to its own woven structure, the metal mesh electrode will dry into a PTFE film with a regular convex structure on its surface after spraying PTFE emulsion, which increases the roughness of the PTFE film and is beneficial to improving the triboelectric performance.

[0076] The support board material is one of basswood and birch board, and has a thickness of 2 mm.

[0077] Preparation method of friction nanogenerator based on SnCl4 modified PVA film,

[0078] (1) Preparation of PVA-SnCl4 modified film;

[0079] (1-1) A 0.05 mol / L SnCl4 solution was prepared in 20 mL of deionized water, and 3 g of PVA particles were added. The mixture was placed in a water bath at 85 °C and magnetically stirred for 3 h.

[0080] (1-2) The PVA-SnCl4 viscous solution obtained above was spin-coated on the surface of the metal foil electrode, with a rotation speed of 1070 rpm for 18 s in the first stage and a rotation speed of 2510 rpm for 60 s in the second stage. Finally, the obtained product was placed in a vacuum drying oven at 50°C for 3 hours;

[0081] (2) Preparation of PTFE spray film on metal mesh substrate

[0082] The PTFE emulsion with a solid content of 60% was ultrasonically vibrated for 10 minutes, and the PTFE emulsion was evenly sprayed on the surface of the metal mesh electrode three times with a spray gun, and then the resultant was placed in a drying oven at 50°C for 3 hours;

[0083] (3) Preparation of contact-separation mode friction nanogenerator

[0084] Basswood board is used as a support board, and double-sided sponge adhesive is pasted on the basswood board as a buffer layer. Take one of the boards, paste the PVA-SnCl4 modified film prepared on the surface of the copper foil as a whole on the surface of the sponge buffer layer, and lead out a wire from the bottom surface of the copper foil, and this part is used as a movable electrode; the PTFE spray coating of the copper mesh substrate is pasted on the surface of the sponge buffer layer of the other board, and a wire is led out from the bottom of the copper mesh, and this part is used as a fixed electrode;

[0085] (4) Preparation of lateral sliding mode friction nanogenerator

[0086] Basswood board is used as a support board, and double-sided sponge adhesive is pasted on the basswood board as a buffer layer. Two of the modules are taken, and the PVA-SnCl4 modified film prepared on the surface of the copper foil is divided into four small pieces and pasted on the surface of the sponge buffer layer. At the same time, the four small pieces are connected in parallel from the lower surface of the copper foil, and then the wire is led out. This part is used as a fixed electrode; the PTFE spray coating of the copper mesh substrate is pasted on the surface of the sponge buffer layer of the other two modules, which is also four small pieces, and then they are connected in parallel from the bottom of the copper mesh, and then the wire is led out. This part is used as a fixed electrode;

[0087] (5) Performance of friction nanogenerator in contact separation-lateral sliding synergistic mode

[0088] The maximum output power generated by triboelectric properties can reach 14.02mW, which is enough to drive micro sensors, enable commercial calculators to work properly, and illuminate large-scale LED arrays without battery power.

[0089] The present invention also includes an application of a frictional power generation motion detection system manufactured based on a contact-separation mode friction nanogenerator, and the frictional power generation motion detection system can be used to detect motion characteristics at different joints of the human body.

[0090] The system comprises a triboelectric sensor made of a nanogenerator, a WIFI data transmission module, a single-chip computer data acquisition module and a host computer data display module.

[0091] The voltage at both ends of the finger bending sensor obtained in the experiment is connected to the ADC data acquisition port of the single-chip computer and the WIFI module can be used to observe the voltage pulse waveform of the triboelectric sensor under the stimulation of finger movement in real time on the host computer. The hand posture can be analyzed by collaborative analysis of the five signals.

[0092] In each motion detection triboelectric sensor, their basic structure is a contact-separation mode triboelectric nanogenerator. The main detection part is widened, the upper and lower substrates are made of lead drawing paper, and the interval filler is a double-sided sponge adhesive. In order to ensure the sensitivity of this type of sensor, there is a 0.3 mm thick protrusion design on each contact surface.

[0093] Figure 6 (a) A diagram of a finger bending detection sensor based on a contact-separation mode friction nanogenerator. Figure 6 (b) Voltage output characteristic diagram of the finger bending detection sensor at different bending degrees at a bending frequency of 1 Hz.

[0094] The PVA-SnCl4 / PTFE contact-separation mode configuration is used to design a triboelectric motion sensor to achieve self-driving of the sensing system. The core part of the PVA-SnCl4 / PTFE triboelectric nanogenerator is the internal protrusion, which has a size of 1cm×2cm×0.3cm. Two pairs of protrusions are arranged side by side in the elbow joint and knee joint sensors. This type of sensor can generate corresponding pulse voltage and current by itself under external mechanical stimulation, thus eliminating the need for external power supply equipment.

[0095] Compared with ordinary motion detection sensors, the friction-generated motion sensor designed based on the PVA-SnCl4 / PTFE contact-separation mode configuration responds faster to external mechanical stimuli (the response speed to finger bending is 12ms), which can meet the requirements of high response accuracy in the fields of robotic training detection and body rehabilitation monitoring.

[0096] Compared with traditional motion detection sensors, this motion detection sensor has the characteristics of not consuming extra power and having a faster response speed. The PVA-SnCl4 / PTFE contact-separation mode configuration design triboelectric motion sensor converts mechanical stimulation into electrical pulse signals, does not require battery power, avoids the sensor's dependence on battery power, and lays the foundation for the development of self-driven, high-performance motion detection sensor technology.

[0097] Embodiment 2:

[0098] Preparation method of friction nanogenerator based on SnCl4 modified PVA film:

[0099] like Figure 1 As shown, it includes a basswood support plate 1, a double-sided sponge adhesive buffer layer 2, a copper mesh electrode 3, a PTFE spray layer 4, a copper foil electrode 5, and a PVA-SnCl4 modified film 6. The basswood board is used as a support plate, and the double-sided sponge adhesive is attached to the basswood board as a buffer layer. The copper foil tape and the copper mesh are attached to the surface of the sponge, and wires are led out from their bottom layers. There are two modules in the contact separation mode part. PTFE emulsion is sprayed on the module with the copper mesh and this part is used as a fixed electrode. PVA-SnCl4 modified film is spin-coated on the module with the copper foil and this part is used as a moving electrode. There are four modules in the lateral sliding mode part. Take two of them, spin-coat the PVA-SnCl4 modified film on the surface of the copper foil, and then distribute these two modules as fixed electrodes on both sides of the entire device. The surfaces of the other two copper foils are sprayed with PTFE emulsion and used as moving electrodes. The effective power generation area of ​​the contact separation mode part is 50cm 2 (5cm×10cm), the effective power generation area of ​​each of the four electrodes in the lateral sliding mode is 7.5cm 2 (1.5cm×5cm).

[0100] The operating mechanism of the triboelectric nanogenerator based on SnCl4 modified PVA film:

[0101] like Figure 2 As shown in (a), in stage i, the moving electrode part moves to the right under the action of external force, thereby generating induced charges on the upper and lower electrodes, and electrons flow upward through the external load. In stage ii, the upper and lower electrodes are completely offset. The induced charges of the upper and lower electrodes are saturated. In stage iii, the moving electrode moves to the left under the action of external force, and the electrons flow downward first; when the upper and lower electrodes are exactly aligned, the upper and lower electrodes reach a state of equilibrium, and as the moving electrode continues to move to the left, induced charges are generated between the two electrodes, and electrons still flow upward through the external load. In stage iv, the upper and lower electrodes are completely offset again, and the induced charges on the two electrodes are saturated again. From then on, it enters a cyclic working state.

[0102] like Figure 2As shown in (b), in the initial stage, there is no induced charge on the two friction layers. In stage ii, the moving electrode contacts the fixed electrode under the action of external force, thereby inducing positive and negative charges on the PVA-SnCl4 film and PTFE spray layer, respectively. In stage iii, the moving electrode is separated from the fixed electrode under the action of external force, and a downward electron flow is generated in the external circuit, inducing positive charges on the copper mesh and negative charges on the copper foil. In stage iv, the induced charges on each electrode are saturated. In stage v, the external force again pushes the moving electrode to approach the fixed electrode, thereby generating an upward electron flow. Then the entire system enters stage ii again, repeating the cycle, and finally realizing external power supply.

[0103] like Figure 3 As shown, the output end of the contact separation-lateral sliding cooperative mode friction nanogenerator is connected to the input end of the rectification and filtering circuit, and finally the direct current is used to supply power to the outside.

[0104] Figure 8 A diagram showing a triboelectric sensor for detecting stepping behavior made based on a contact-separation mode triboelectric nanogenerator.

[0105] Fig. 9 (a) is the voltage curve of the pedaling behavior detection sensor in response to different pedaling conditions. It can be seen that the pulse voltage values ​​under jogging, jumping and normal walking conditions are significantly different; Fig. 9 (b) is the response time curve of the pedaling behavior detection sensor of an embodiment of the present invention under normal walking conditions. It can be seen that its response / recovery time is very short, which are 26ms and 44ms respectively.

[0106] Embodiment 3:

[0107] An application of a friction-generated motion detection system based on a contact-separation mode friction nanogenerator.

[0108] Finger bending feature analysis and Labview five-finger signal synchronous transmission display:

[0109] The voltage data of the finger under different bending states were sampled and analyzed:

[0110] Figure 6 (b) is the voltage output characteristic diagram of the finger bending detection sensor at different bending degrees at a bending frequency of 1 Hz. The bending condition of the finger can be judged from the size of the voltage value.

[0111] Fig.10 (a) is a physical picture of the integrated five-finger bending detection sensor. It can be seen that the driving pull ring of each sensor is accurately fitted on the corresponding finger, and the output end of each sensor is connected to the integrated data acquisition port.

[0112] Fig.10 (b) is a unified real-time display of five signals using a host computer written in Labview. The real-time wireless transmission of detection data is achieved using the STM32F407 microcontroller, WIFI module and Labview host computer. The hand posture can be analyzed by collaborative analysis of the five signals.

[0113] The contact separation-lateral sliding cooperative mode friction nanogenerator proposed by the present invention has a higher output power than each part working alone; the motion detection sensor designed based on the contact separation mode has the characteristics of not consuming extra power and having a faster response speed compared with the traditional motion detection sensor. This type of triboelectric sensor converts mechanical stimulation into an electrical pulse signal, does not require battery power, and avoids the sensor's dependence on battery power.

[0114] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable ordinary technicians in the field to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made based on the essence of the content of the present invention should be included in the protection scope of the present invention.

Claims

1. A friction nanogenerator based on tin tetrachloride / modified polyvinyl alcohol film, characterized by: The nanogenerator is composed of a contact-separation mode part and a lateral sliding mode part, with SnCl4-modified PVA film and a PTFE spray-coated film on a metal mesh substrate as a power generation layer, and the contact-separation mode part and the lateral sliding mode part work together to convert mechanical energy in the environment into electrical energy; The contact-separation mode friction nanogenerator requires two modules: a basswood board is used as a support board, and a sponge double-sided adhesive is attached to the basswood board as a buffer layer. Take one of the boards, and stick the PVA-SnCl4 modified film prepared on the copper foil surface on the surface of the sponge buffer layer as a whole. At the same time, a wire is led out from the bottom surface of the copper foil. This part is used as a movable electrode; the PTFE spray coating of the aforementioned copper mesh substrate is attached to the surface of the sponge buffer layer of the other board, and a wire is led out from the bottom of the copper mesh. This part is used as a fixed electrode; the lateral sliding mode friction nanogenerator requires Four modules are to be prepared: basswood is used as a support board, and double-sided sponge adhesive is pasted on the basswood as a buffer layer. Two of the modules are taken, and the PVA-SnCl4 modified film prepared on the copper foil surface is divided into four small pieces and pasted on the surface of the sponge buffer layer. At the same time, the four small pieces are connected in parallel from the bottom surface of the copper foil, and then the wires are led out. This part is used as a fixed electrode; the PTFE spray coating of the aforementioned copper mesh substrate is pasted on the surface of the sponge buffer layer of the other two modules, which is also four small pieces, and then they are connected in parallel from the bottom of the copper mesh, and then the wires are led out. This part is used as a fixed electrode; The spacing between the power generation layers in the contact-separation mode is the same as the spacing between the four electrodes in the lateral sliding mode. The four small modules in each section of the lateral sliding mode TENG are connected in parallel at the bottom of the electrode to reduce the output port and reduce current loss. The contact-separation-lateral sliding synergistic mode friction nanogenerator can generate pulse voltage during reciprocating motion.

2. The friction nanogenerator based on tin tetrachloride / modified polyvinyl alcohol film according to claim 1 is characterized in that: The contact-separation mode is composed of a support plate, a sponge buffer layer, a metal mesh electrode, a PTFE spray layer, a PVA-SnCl4 modified film, a metal foil electrode, a sponge buffer layer and a support plate from top to bottom.

3. The friction nanogenerator based on tin tetrachloride / modified polyvinyl alcohol film according to claim 2 is characterized in that: The lateral sliding modes are provided with two groups, symmetrically distributed on both sides of the contact and separation mode part, and each group of lateral sliding modes is provided with four groups of identical power generation modules; The power generation module comprises, from the inside to the outside, a support plate, a sponge buffer layer, a metal foil electrode, a PVA-SnCl4 modified film, a PTFE spray layer, a metal foil electrode and a support plate.

4. The friction nanogenerator based on tin tetrachloride / modified polyvinyl alcohol film according to claim 3 is characterized in that: The distance between the PTFE spray layer and the PVA-SnCl4 modified film in the contact separation mode is equal to the distance between adjacent power generation modules in the lateral sliding mode; The electrodes corresponding to the bottom layer of the PVA-SnCl4 modified film are connected to the same port, and the electrodes corresponding to the bottom layer of the PTFE spray coating film are connected to another port, and the two ports are respectively two input ends of the rectifier filter circuit; The output electrical signal of the friction nanogenerator is rectified and filtered to supply power to the outside in the form of direct current. The DC voltage in the contact and separation mode is 131.63V, and the DC voltage in the lateral sliding mode is 25.76V.

5. The triboelectric nanogenerator based on tin tetrachloride / modified polyvinyl alcohol film according to any one of claims 2 or 3, characterized in that: The material of the metal mesh electrode and the metal foil electrode is one of Al, Cu, Ni and Ag, the thickness of the metal mesh electrode is 100 microns, and the thickness of the metal foil electrode is 100 microns; The support board is one of a basswood board and a birch board, and has a thickness of 2 mm.

6. A method for preparing a triboelectric nanogenerator based on tin tetrachloride modified polyvinyl alcohol film, wherein the triboelectric nanogenerator has the triboelectric nanogenerator according to any one of claims 1 to 5, characterized in that: (1) Preparation of PVA-SnCl4 modified film; (2) preparing a PTFE spray film on a metal mesh substrate; (3) Preparation of contact-separation mode friction nanogenerator; (4) Preparation of a friction nanogenerator in lateral sliding mode; (5) Combining the friction nanogenerator in contact-separation mode and the friction nanogenerator in lateral sliding mode.

7. The method for preparing a triboelectric nanogenerator based on tin tetrachloride / modified polyvinyl alcohol film according to claim 6, characterized in that: The specific steps of step (1) include: (1-1) A 0.05 mol / L SnCl4 solution was prepared in 20 mL of deionized water, and 3 g of PVA particles were added. The mixture was placed in a water bath at 85 °C and magnetically stirred for 3 h. (1-2) Spin coating the PVA-SnCl4 viscous solution obtained in step (1-1) on the surface of the metal foil electrode, rotating at a speed of 1070 rpm for 18 s in the first stage and rotating at a speed of 2510 rpm for 60 s in the second stage, and finally placing the resultant in a vacuum drying oven at 50°C for 3 hours; The specific steps of step (2) include: Ultrasonic vibration was performed on a PTFE emulsion with a solid content of 60% for 10 minutes, and the PTFE emulsion was evenly sprayed on the surface of the metal mesh electrode three times with a spray gun, and the resultant was placed in a drying oven at 50°C for 3 hours; The specific steps of step (3) include: A basswood board is used as a support board, and a double-sided sponge adhesive is attached to the basswood board as a buffer layer. Two identical boards are prepared. Take one of the boards, and the PVA-SnCl4 modified film prepared on the surface of the metal foil in step (1) is attached to the surface of the sponge buffer layer as a whole, and a wire is led out from the lower surface of the metal foil to serve as a movable electrode; the PTFE spray coating of the metal mesh substrate prepared in step (2) is attached to the surface of the sponge buffer layer of the other board, and a wire is led out from the bottom of the metal mesh to serve as a fixed electrode; The specific steps of step (4) include: The lateral sliding modes are provided with two groups, and the preparation method of each group of lateral sliding modes is the same, including: A basswood board is used as a support board, and a double-sided sponge adhesive is attached to the basswood board as a buffer layer. Two identical boards are prepared, and the surface of the sponge buffer layer of one board is attached with a PVA-SnCl4 modified film with a metal electrode substrate prepared on the surface of the metal foil in step (1), and at the same time, the PVA-SnCl4 modified film electrode is connected in parallel from the lower surface of the metal foil, and a wire is led out, and this part is used as a fixed electrode; the surface of the sponge buffer layer of the other board is attached with a PTFE spray layer prepared on the metal mesh substrate in step (2), and parallel connections are made from the bottom of the metal mesh, and then a wire is led out, and this part is used as a fixed electrode; The specific steps of step (5) include: Two sets of lateral sliding modes are symmetrically fixed on both sides of the contact-separation mode part.

8. A frictional power generation motion detection system based on a frictional nanogenerator of tin tetrachloride / modified polyvinyl alcohol film, wherein the nanogenerator has a frictional nanogenerator according to any one of claims 1 to 5, or is prepared according to the preparation method according to any one of claims 6 to 7, characterized in that: The friction power generation motion detection system can be used to detect motion characteristics at different joints of the human body.

9. The frictional power generation motion detection system of the friction nanogenerator based on tin tetrachloride / modified polyvinyl alcohol film according to claim 8, characterized in that: The system includes a triboelectric sensor made of a nanogenerator, a WIFI data transmission module, a single-chip computer data acquisition module and a host computer data display module; The support plate, sponge buffer layer, metal mesh electrode, PTFE spray layer, PVA-SnCl4 modified film and metal foil electrode of the contact separation mode are all provided with a protruding portion with a thickness of 0.3 mm.

10. The frictional power generation motion detection system of the friction nanogenerator based on tin tetrachloride / modified polyvinyl alcohol film according to claim 8, characterized in that: The voltage across the triboelectric sensor of the bent finger obtained in the experiment is connected to the ADC data acquisition port of the microcontroller and the WIFI module can be used to observe the voltage pulse waveform of the triboelectric sensor under the stimulation of finger movement in real time on the host computer; the hand posture can be resolved by collaboratively analyzing the five signals.

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