Variable-frequency energy collection friction nanometer generator device and preparation method thereof

Abstract

The invention provides a frequency conversion energy collection friction nanometer generator device and a preparation method thereof, and the device comprises a frequency conversion mechanism which comprises a mass block and is used for sensing the low-frequency vibration of a human body and generating corresponding vibration motion; the frequency conversion assembly comprises a rotation driving assembly and a transmission assembly connected with the rotation driving assembly, the rotation driving assembly is connected with the mass block, and vibration of the mass block can drive the rotation driving assembly to drive the transmission assembly to rotate at the rotation frequency corresponding to the low-frequency vibration frequency; the power generation mechanism comprises a first shell, a rotating rod is arranged on the first shell in a penetrating mode, the rotating rod is connected with a transmission assembly, a friction material adheres to the rotating rod, an electrode assembly is attached to the position, opposite to the friction material, of the inner surface of the first shell, and when the transmission assembly rotates, friction of relative displacement is generated between the friction material and an electrode, so that periodic transfer of charges is achieved; low-frequency vibration can be converted into rotation frequency suitable for power generation, and the problem that low-frequency vibration of a human body is difficult to be directly used for power generation is solved.

Description

Technical Field

[0001] The present application relates to the technical field, and in particular to a variable frequency energy harvesting friction nanogenerator device and a preparation method thereof. Background Art

[0002] With the continuous development of Internet of Things technology, the application of wearable electronic devices that are lightweight, portable and highly integrated is becoming more and more widespread, while traditional battery-powered methods face many problems such as repeated charging and discharging and environmental pollution.

[0003] With the rapid development of low-power integrated circuits, wireless communications and mobile electronics, the requirements for power consumption have been greatly reduced. At present, the power consumption of many sensors has been reduced to milliwatts or even microwatts, and the possibility of using energy harvesting devices as power supply devices for sensors has increased. Taking into account the characteristics of low frequency, small amplitude, and uncertain vibration direction during movement of the human body, the use of friction nanogenerators for power generation has the advantages of high reliability, strong environmental adaptability, high overall output, simple production and principle, and environmental protection, and is more suitable for energy collection in low-frequency movement of the human body. However, the current wearable friction nanogenerator is not efficient in collecting low-frequency vibration energy, and even cannot collect energy at lower frequencies. Summary of the invention

[0004] In view of the above-mentioned defects or deficiencies in the prior art, the present application aims to provide a variable frequency energy harvesting friction nanogenerator device and a preparation method thereof, so as to improve the current wearable friction nanogenerator's efficiency in harvesting low-frequency vibration energy.

[0005] In the first aspect, a variable frequency energy harvesting friction nanogenerator device is provided, comprising: A frequency conversion mechanism, the frequency conversion mechanism comprising: A mass block, the mass block is used to sense low-frequency vibrations of the human body and generate corresponding vibration motions; A frequency conversion component, the frequency conversion component includes a rotation drive component and a transmission component connected thereto, the rotation drive component is connected to the mass block, and the vibration movement of the mass block can drive the rotation drive component to drive the transmission component to rotate at a rotation frequency corresponding to the low-frequency vibration frequency; The power generation mechanism comprises a first shell, a rotating rod is penetrated through the first shell, the rotating rod is connected to the transmission component, a friction material is pasted on the rotating rod, an electrode component is attached to the inner surface of the first shell and the relative position of the friction material, when the transmission component rotates, the friction material and the electrode generate relative displacement friction, realize the periodic transfer of charge, and generate periodic alternating current.

[0006] According to the technical solution provided in the embodiment of the present application, the frequency conversion mechanism includes a second shell, the mass block is arranged in the second shell, the rotation drive component is a driving gear, the driving gear is connected to the mass block through a first connecting rod, and the transmission component includes a driven gear meshingly connected to the driving gear, and the driven gear is connected to the rotating rod; the gear ratio between the driven gear and the driving gear is 2:3.

[0007] According to the technical solution provided in the embodiment of the present application, a transmission rod is connected to the driven gear near the power generation mechanism, and the transmission rod is connected to the rotating rod at the end away from the driven gear.

[0008] According to the technical solution provided in the embodiment of the present application, the frequency conversion mechanism also includes a one-way bearing, which is connected to the driving gear; when the human body is in forward vibration excitation, the one-way bearing is in a stuck state, and when the human body is in reverse vibration excitation, the one-way bearing is in a rotatable state.

[0009] According to the technical solution provided in the embodiment of the present application, a plurality of first mounting rods are distributed in an array on the circumference of the rotating rod, the first mounting rods are placed in the first shell, every two adjacent first mounting rods form a mounting portion, and the friction material is pasted on all the mounting portions at intervals.

[0010] According to the technical solution provided in the embodiment of the present application, the electrode assembly includes a plurality of first electrodes and a second electrode having the same number as the first electrodes, and the first electrodes and the second electrodes are alternately arranged on the inner surface of the first shell; the first electrode and the second electrode are both laser-induced graphene electrodes.

[0011] According to the technical solution provided in the embodiment of the present application, the second shell has a mounting plate integrally formed with the second shell, and the first rotating shaft of the driving gear is provided on the mounting plate.

[0012] According to the technical solution provided in the embodiment of the present application, the friction material is polyetheretherketone.

[0013] According to the technical solution provided in the embodiment of the present application, the transmission rod and the rotating rod can be arranged separately or integrally.

[0014] The second aspect provides a method for preparing a variable frequency energy harvesting friction nanogenerator device, which is used to prepare an electrode assembly in the device; Figure 5 As shown, the following steps are included: S1. Use anhydrous ethanol to clean Nomex insulation paper; wherein the thickness of Nomex insulation paper is 180μm; S2, using a CO2 laser with a wavelength of 10.6 μm, emitting pulsed laser at a scanning interval of 40 μm, a scanning speed of 400 mm / s, and a laser power of 9 W, to perform laser induction on Nomex insulating paper to form laser-induced graphene; S3, encapsulating the laser-induced graphene with PU, and placing the encapsulated laser-induced graphene in a vacuum oven for curing; S4. Emitting pulsed laser at a scanning interval of 30 μm, a scanning speed of 20 mm / s, and a laser power of 6 W to cut the packaged laser-induced graphene into a predetermined structure adapted to the inner surface of the first shell, wherein the predetermined structure is an electrode assembly; wherein each independent layer of the predetermined structure has a size of 20×20 cm², and there is a connection of 3×0.3 cm² between each adjacent segment.

[0015] Compared with the prior art, the beneficial effect of the present application is that the mass block of the present application is specifically used to sense the low-frequency vibration of the human body and generate corresponding vibration motion. The vibration of the human body is often low-frequency and irregular. The mass block can keenly capture this vibration and provide initial power for subsequent energy conversion. The rotation drive component in the frequency conversion component is connected to the mass block. The vibration of the mass block drives the rotation drive component, which in turn drives the transmission component to rotate at a rotation frequency corresponding to the low-frequency vibration frequency, converting the mechanical energy of the low-frequency vibration of the human body into the rotational mechanical energy of the transmission component, and through the frequency conversion component, the low-frequency vibration is converted into a rotation frequency suitable for power generation, solving the problem that the low-frequency vibration of the human body is difficult to be directly used for power generation. The rotating rod of the power generation mechanism is connected to the transmission component, so that the rotational motion of the transmission component can be transmitted to the rotating rod. When the rotating rod rotates with the transmission component, the friction material and the electrode generate friction of relative displacement. According to the principle of the friction nanogenerator, this friction will cause the periodic transfer of charge, thereby generating a periodic alternating current, successfully converting mechanical energy into electrical energy, and achieving the purpose of energy collection. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A schematic diagram of the structure of a variable frequency energy harvesting friction nanogenerator device (generator mechanism side) provided in an embodiment of the present application; Figure 2 A schematic diagram of the structure of a variable frequency energy harvesting friction nanogenerator device (frequency conversion mechanism side) provided in an embodiment of the present application; Figure 3 A schematic diagram of the structure of the driving gear and the driven gear provided in the embodiment of the present application; Figure 4 A schematic diagram of the structure of an electrode assembly provided in an embodiment of the present application; Figure 5 A schematic flow chart of the steps of a method for preparing a variable frequency energy harvesting friction nanogenerator device provided in an embodiment of the present application.

[0017] The text annotations in the figure represent: 1. Second shell; 2. First shell; 3. Friction material; 4. Rotating rod; 5. Electrode assembly; 51. First electrode; 52. Second electrode; 6. First mounting rod; 7. Driven gear; 8. Driving gear; 9. First connecting rod; 10. Mass block; 11. Support structure; 12. First rotating shaft. DETAILED DESCRIPTION

[0018] The present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the relevant invention, rather than to limit the invention. It is also necessary to explain that, for ease of description, only the parts related to the invention are shown in the accompanying drawings.

[0019] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0020] Example 1 As mentioned in the background technology, in view of the problems in the prior art, the present application proposes a method for preparing a variable frequency energy harvesting friction nanogenerator device, which is used to prepare an electrode assembly 5 in the device; the method comprises the following steps: S1. Use anhydrous ethanol to clean Nomex insulation paper; wherein the thickness of Nomex insulation paper is 180μm; S2, using a CO2 laser with a wavelength of 10.6 μm, emitting pulsed laser at a scanning interval of 40 μm, a scanning speed of 400 mm / s, and a laser power of 9 W, to perform laser induction on Nomex insulating paper to form laser-induced graphene; S3, encapsulating the laser-induced graphene with PU, and placing the encapsulated laser-induced graphene in a vacuum oven for curing; Specifically, curing was performed at 150°C for 20 minutes.

[0021] S4. Emitting pulsed laser at a scanning interval of 30 μm, a scanning speed of 20 mm / s, and a laser power of 6 W to cut the packaged laser-induced graphene into a predetermined structure adapted to the inner surface of the first shell 2, wherein the predetermined structure is an electrode assembly 5; wherein each independent layer of the predetermined structure has a size of 20×20 cm², and there is a connection of 3×0.3 cm² between each adjacent segment.

[0022] Specifically, the cutting is performed along a sawtooth cutting path, and the left and right sides after cutting serve as the first electrode 51 and the second electrode 52 respectively.

[0023] Example 2 Based on Example 1, this example proposes a variable frequency energy harvesting friction nanogenerator device, such as Figure 1 and Figure 2 As shown, including: A frequency conversion mechanism, the frequency conversion mechanism comprising: A mass block 10, wherein the mass block 10 is used to sense low-frequency vibrations of a human body and generate corresponding vibration motions; A frequency conversion component, the frequency conversion component includes a rotation drive component and a transmission component connected thereto, the rotation drive component is connected to the mass block 10, and the vibration movement of the mass block 10 can drive the rotation drive component to drive the transmission component to rotate at a rotation frequency corresponding to the low-frequency vibration frequency; A power generation mechanism includes a first shell 2, a rotating rod 4 is penetrated through the first shell 2, the rotating rod 4 is connected to the transmission component, a friction material 3 is pasted on the rotating rod 4, and an electrode component 5 is attached to the relative position between the inner surface of the first shell 2 and the friction material 3. When the transmission component rotates, the friction material 3 and the electrode generate relative displacement friction, realizing the periodic transfer of charge to generate a periodic alternating current.

[0024] Specifically, a support structure 11 is provided in the first shell 2 and is integrally formed with the first shell 2 . The support structure 11 is used to support the first shell 2 and prevent deformation during the manufacturing process of the first shell 2 .

[0025] In a preferred embodiment, the friction material 3 is polyetheretherketone (PEEK).

[0026] The choice of friction material 3 for triboelectric nanogenerators is very wide, and common materials all have the characteristics of triboelectric charging. Different materials have different abilities to gain and lose electrons, which are usually measured according to the triboelectric series. This series shows the relative positions of different materials, and the farther the position, the greater the amount of charge transfer. The selected friction layer area is about 80cm 2 We tried different materials (PI and PEEK) of the same thickness (0.1μm) and independent layer friction nanogenerator electrodes for independent layer power generation. The power generation performance of different materials is expressed by voltage. When PI is used as friction material 3, the maximum output of TENG is 33.1V, and when PEEK is used as friction material 3, the maximum output of TENG is 55.3V. It can be seen that compared with PI, PEEK has better power generation performance. And PEEK has better stiffness, and can have better contact as the friction layer of the rotating disc friction nanogenerator; and its surface is smoother, and the external excitation required to drive it to rub is also smaller. Therefore, PEEK is used as friction material 3 for friction power generation.

[0027] Specifically, the output performance of TENG often depends on the surface charge density, which is related to the effective contact area of ​​the triboelectric layer and the thickness of the triboelectric material. The thickness of the triboelectric material will directly affect the output performance of TENG. Theoretical studies have shown that the output performance of TENG tends to increase with the decrease of the thickness of the triboelectric material film. The output performance of TENG can be improved by reducing the thickness of the triboelectric material film. To this end, 0.1mm, 0.2mm, and 0.3mm PEEK films were placed on the device to study the effects of different triboelectric material thicknesses on the output performance of the device in order to explore the optimal film thickness. The open circuit voltage was used to characterize the output performance. The open circuit voltage of TENG under 1Hz excitation showed a trend of change with the thickness of the PEEK film. As the PEEK dielectric film increased, the output voltage of TENG continued to decrease. Therefore, the output performance was optimal when the thickness of the friction material prepared by the PEEK film was 0.1mm.

[0028] In a preferred embodiment, if Figure 4 As shown, the electrode assembly 5 includes a plurality of first electrodes 51 and the same number of second electrodes 52 as the first electrodes 51 , and the first electrodes 51 and the second electrodes 52 are alternately arranged on the inner surface of the first shell 2 ; the first electrodes 51 and the second electrodes 52 are both laser induced graphene electrodes.

[0029] Specifically, as shown in the figure, there are three first electrodes 51 and three second electrodes 52. The heights of the first electrodes 51 and the second electrodes 52 are the same, both of which are half the height of the inner surface of the first shell 2. The first electrodes 51 and the second electrodes 52 are distributed in a forked finger shape. The first electrodes 51 are connected to each other as a passage, and the second electrodes 52 are connected to each other as a passage. The first electrode 51 is attached to the lower half of the inner surface of the first shell 2 along its height direction, and the second electrode 52 is attached to the upper half of the inner surface of the first shell 2 along its height direction, and each first electrode 51 and each second electrode 52 are arranged alternately.

[0030] Specifically, after conducting a comparative test on the triboelectric properties of PI and friction material 3 (PEEK) of the same thickness (0.1μm), PEEK was selected as friction material 3 according to the triboelectric series of different materials because it has better power generation performance than PI, better stiffness, smoother surface, and smaller external excitation required to drive it for friction. When this material is used in conjunction with a laser induced graphene electrode (LIG electrode), under the triboelectric effect, based on the independent layer friction nanogenerator working mode, it can generate equal amounts of different types of charges on the electrode surface to achieve triboelectric power generation.

[0031] In a preferred embodiment, the frequency conversion mechanism includes a second housing 1, the mass block 10 is disposed in the second housing 1, the rotation drive component is a driving gear 8, and the driving gear 8 is connected to the mass block 10 through a first connecting rod 9. Figure 3 As shown, the transmission assembly includes a driven gear 7 meshingly connected with the driving gear 8, and the driven gear 7 is connected to the rotating rod 4; the gear ratio of the driven gear 7 to the driving gear 8 is 2:3.

[0032] In a preferred embodiment, a transmission rod is connected to the driven gear 7 near the power generation mechanism, and an end of the transmission rod away from the driven gear 7 is connected to the rotating rod 4 .

[0033] Specifically, the entire device is encapsulated by a first shell and a second shell. Both the first shell and the second shell are disc-shaped structures. The first shell wraps the LIG electrode of the power generation part and the internal rotating rod 4 to play a protective and supporting role. At the same time, the first shell, the second shell and the transmission rod are all made of 3D printed photosensitive resin materials. This material gives the entire device the advantages of low density, lightness, high strength, and strong toughness. In addition, through integrated molding, no additional assembly is required, which helps to reduce costs. 3D printed photosensitive resins have high precision. Using SLA and DLP technology, photosensitive resins can achieve more printing details compared to other 3D printing technologies using FDM; using light curing technology, each layer has high printing precision, the printed material surface is smooth and flat, and the material has high strength and high elasticity. The inner diameter of the overall device is 100mm, the outer diameter is 110mm, and the height is 60mm.

[0034] Specifically, the mass block 10 senses external vibration signals, and the mass block 10 can sense low-frequency vibrations from human movement or other external environments, such as low-frequency vibrations from human walking, arm swinging, etc. When the mass block 10 senses vibration, the vibration of the mass block 10 drives the driving wheel in the frequency conversion gear set connected to it to rotate, converting the vibration into rotational motion.

[0035] Specifically, after the driving gear 8 rotates, the driving gear 8 and the driven gear 7 are meshed with each other, which will drive the driven gear 7 to rotate. In this process, the transmission ratio of the gear set of the frequency conversion component is 2:3, which means that the rotation speed and number of teeth of the driving gear 8 and the driven gear 7 are set according to a certain ratio. At the same time, according to the vibration range of the vibration motion of the mass block 10 (here is 120°), when the external vibration is one cycle, due to the effect of the gear transmission ratio, the driven gear 7 will drive the transmission rod to rotate at a specific speed, so that the rotating rod 4 rotates half a circle, and the device goes through 2 to 3 power generation cycles. This design is to enable the entire device to better adapt to the characteristics of low-frequency motion of the human body and optimize the collection of low-frequency vibrations.

[0036] In a preferred embodiment, the frequency conversion mechanism also includes a one-way bearing, which is connected to the driving gear 8; when the human body is in positive vibration excitation, the one-way bearing is in a stuck state, and when the human body's low-frequency vibration is in reverse vibration excitation, the one-way bearing is in a rotatable state.

[0037] Specifically, in one application scenario, the wearable friction nanogenerator is installed on the human body or on a wearable assistive tool to collect energy from human body vibration to provide electrical energy for the movement of the wearable assistive tool. When the human body is in forward vibration excitation (the direction of low-frequency vibration of the human body), the one-way bearing is stuck and the follower mass block 10 rotates forward to ensure that the active gear 8 drives the driven gear 7 to rotate normally; when the human body is in reverse vibration excitation (the direction of low-frequency vibration of the human body), the one-way bearing is not stuck (rotatable state), and due to inertia, the driving gear continues to make forward rotation with reduced acceleration, ensuring that under vibration excitation in different directions, the device can maintain stable rotational motion transmission, avoiding the continuity of energy collection due to changes in vibration direction.

[0038] In a preferred embodiment, a plurality of first mounting rods 6 are distributed in an array circumferentially on the rotating rod 4, the first mounting rods 6 are placed in the first shell 2, and every two adjacent first mounting rods 6 form a mounting portion, and the friction material 3 is pasted on all the mounting portions at intervals.

[0039] Optionally, since the PEEK and LIG electrodes adopt the working mode of independent layer friction nanogenerators, the relative displacement between them will cause the triboelectric effect. Under the triboelectric effect, according to the difference in electronegativity, the surfaces of the PEEK and LIG electrodes will carry equal amounts of different types of charges, and as the relative displacement changes, the charges will be transferred between the electrode surface and the surface of the friction material 3, thereby generating current. At different stages of triboelectricity, when the second electrode 52 in the PEEK and LIG electrodes is in full contact, the two are in an electrostatic equilibrium state and no current is generated; when the PEEK starts to rotate and relatively slides with the electrode, according to the principle of electrostatic induction, the positive charge is gradually transferred from the second electrode 52 to the first electrode 51, and a current from the second electrode 52 to the first electrode 51 will be generated when an external resistor is connected; when the PEEK is in full contact with the first electrode 51, a new electrostatic equilibrium will be reached, and there will be no current in the external circuit; when the rotation continues, the positive charge will gradually transfer from the first electrode 51 to the second electrode 52, and a current from the first electrode 51 to the second electrode 52 will be generated when an external resistor is connected. In this way, as the rotating rod 4 continues to rotate, the charge in the external circuit changes periodically, and the current direction changes once in each cycle, and finally an alternating signal is output to achieve the output of alternating current and complete the collection of low-frequency motion energy of the human body.

[0040] Specifically, in order to explore the effect of different independent layer electrode segment numbers on the output, 5 segments (electrode friction layer area is 24*20cm 2 *5), 6 sections (the electrode friction layer area is 20*20cm 2 *6), 7 segments (the electrode friction layer area is 17.2*20cm 2 *7) The output performance of the device was tested using the same excitation (1 Hz) for different number of independent layered triboelectric nanogenerator electrodes. Since the friction contact area remained unchanged (all 120 cm 2 ), different number of LIG electrodes have little effect on the output, and the output performance is better when the number of LIG electrode segments is 6. This is because more segments will make the surface of the friction layer rougher as a whole, which will hinder the movement of the structure, and the energy loss will be greater under the same excitation, and the energy transferred to TENG will have less impact on the output performance of the device; while fewer segments will cause the frequency of transferred charges generated under low-frequency excitation to be lower than that of more segments, thereby affecting the output performance of the device. Therefore, 6 segments of LIG electrodes are selected, namely 3 segments of first electrodes 51 and 3 segments of second electrodes 52, and 6 first mounting rods 6 are correspondingly arranged, and there are 3 friction materials 3 on the first mounting rods 6.

[0041] In a preferred embodiment, the second housing 1 has a mounting plate integrally formed with the second housing 1 , and the mounting plate is provided with the first rotating shaft 12 of the driving gear 8 .

[0042] Specifically, the mounting plate and the second shell 1 are integrally formed to form a fan-shaped plate structure.

[0043] In a preferred embodiment, the transmission rod and the rotating rod 4 can be separately arranged or integrally arranged.

[0044] This article uses specific examples to illustrate the principles and implementation methods of this application. The description of the above embodiments is only used to help understand the method and its core ideas of this application. The above is only the preferred implementation method of this application. It should be pointed out that due to the limitations of textual expression and the objective existence of infinite specific structures, ordinary technicians in this technical field can make several improvements, modifications or changes without departing from the principles of the present invention, and can also combine the above technical features in an appropriate manner; these improvements, modifications, changes or combinations, or the direct application of the inventive concept and technical solution to other occasions without improvement, should be regarded as the scope of protection of this application.

Claims

1. A variable frequency energy harvesting friction nanogenerator device, characterized in that: include: A frequency conversion mechanism, the frequency conversion mechanism comprising: A mass block (10), the mass block (10) being used to sense low-frequency vibrations of a human body and generate corresponding vibration motions; A frequency conversion component, the frequency conversion component comprising a rotation drive component and a transmission component connected thereto, the rotation drive component being connected to the mass block (10), the vibration movement of the mass block (10) being able to drive the rotation drive component to drive the transmission component to rotate at a rotation frequency corresponding to the low-frequency vibration frequency; A power generation mechanism, the power generation mechanism comprising a first shell (2), a rotating rod (4) passing through the first shell (2), the rotating rod (4) being connected to the transmission component, a friction material (3) being adhered to the rotating rod (4), an electrode component (5) being adhered to the inner surface of the first shell (2) at a relative position to the friction material (3), and when the transmission component rotates, the friction material (3) and the electrode generate friction of relative displacement, thereby realizing periodic transfer of charge and generating periodic alternating current.

2. The variable frequency energy harvesting friction nanogenerator device according to claim 1 is characterized in that: The frequency conversion mechanism comprises a second housing (1), the mass block (10) is arranged in the second housing (1), the rotation drive component is a driving gear (8), the driving gear (8) is connected to the mass block (10) via a first connecting rod (9), the transmission component comprises a driven gear (7) meshingly connected to the driving gear (8), the driven gear (7) is connected to the rotating rod (4); the gear ratio of the driven gear (7) to the driving gear (8) is 2:

3.

3. The variable frequency energy harvesting friction nanogenerator device according to claim 2 is characterized in that: The driven gear (7) is connected to a transmission rod on the side close to the power generation mechanism, and the end of the transmission rod away from the driven gear (7) is connected to the rotating rod (4).

4. The variable frequency energy harvesting friction nanogenerator device according to claim 2 is characterized in that: The frequency conversion mechanism also includes a one-way bearing, which is connected to the driving gear (8); when the human body is in a positive vibration excitation, the one-way bearing is in a stuck state, and when the human body is in a reverse vibration excitation, the one-way bearing is in a rotatable state.

5. The variable frequency energy harvesting friction nanogenerator device according to claim 1, characterized in that: A plurality of first mounting rods (6) are distributed in an array in a circumferential direction on the rotating rod (4), the first mounting rods (6) being disposed in the first housing (2), and every two adjacent first mounting rods (6) forming a mounting portion, and the friction material (3) is adhered to all the mounting portions at intervals.

6. The variable frequency energy harvesting friction nanogenerator device according to claim 5, characterized in that: The electrode assembly (5) comprises a plurality of first electrodes (51) and the same number of second electrodes (52) as the first electrodes (51); the first electrodes (51) and the second electrodes (52) are alternately arranged on the inner surface of the first shell (2); and the first electrodes (51) and the second electrodes (52) are both laser-induced graphene electrodes.

7. The variable frequency energy harvesting friction nanogenerator device according to claim 2 is characterized in that: The second housing (1) has a mounting plate integrally formed with the second housing (1), and the mounting plate is provided with a first rotating shaft (12) of the driving gear (8).

8. The variable frequency energy harvesting friction nanogenerator device according to claim 1, characterized in that: The friction material (3) is polyetheretherketone.

9. The variable frequency energy harvesting friction nanogenerator device according to claim 3 is characterized by: The transmission rod and the rotating rod (4) may be arranged separately or integrally.

10. A method for preparing a variable frequency energy harvesting friction nanogenerator device, used for preparing an electrode assembly (5) in the device; characterized in that: The following steps are involved: S1. Use anhydrous ethanol to clean Nomex insulation paper; wherein the thickness of Nomex insulation paper is 180μm; S2, using a CO2 laser with a wavelength of 10.6 μm, emitting pulsed laser at a scanning interval of 40 μm, a scanning speed of 400 mm / s, and a laser power of 9 W, to perform laser induction on Nomex insulating paper to form laser-induced graphene; S3, encapsulating the laser-induced graphene with PU, and placing the encapsulated laser-induced graphene in a vacuum oven for curing; S4, emitting pulsed laser at a scanning interval of 30 μm, a scanning speed of 20 mm / s, and a laser power of 6 W, to cut the packaged laser-induced graphene into a predetermined structure adapted to the inner surface of the first shell (2), wherein the predetermined structure is an electrode assembly (5); wherein each independent layer of the predetermined structure has a size of 20×20 cm², and there is a connection of 3×0.3 cm² between each adjacent segment.

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