A DC triboelectric nanogenerator employing steel needle electrodes and multi-element dielectric materials, its fabrication method and applications.

Abstract

This invention relates to the field of generator technology for energy conversion and harvesting, and particularly to a DC triboelectric nanogenerator employing steel needle electrodes and multi-element dielectric materials, its fabrication method, and its application. The DC triboelectric nanogenerator consists of component A and component B. Component A includes at least one constituent unit, each of which comprises a triboelectric dielectric material 1 with a back electrode and a triboelectric dielectric material 2 with a back electrode having steel needles. Component B has a triboelectric dielectric material 3 attached to the side facing component A. This DC triboelectric nanogenerator is based on the principle of triboelectric generation using ternary dielectrics. By matching the electronegativity arrangement of the ternary triboelectric materials in space and fabricating a back electrode with steel needles, the triboelectric nanogenerator achieves a constant and stable DC output and a constant and stable high-voltage output. It has the advantages of simple fabrication, high integration, constant and stable DC output, constant and stable high-voltage output, high stability, and high durability.

Description

Technical Field

[0001] This invention relates to the field of generator technology for energy conversion and harvesting, specifically to a triboelectric nanogenerator that uses a back electrode with steel needles and a multi-element dielectric material to achieve DC output, and more particularly to a DC triboelectric nanogenerator using steel needle electrodes and a multi-element dielectric material, its fabrication method, and its application. Background Technology

[0002] Triboelectric nanogenerators (TENGs) can effectively convert mechanical motion in various environments into electrical energy based on the coupling effect of triboelectricity and electrostatic induction. However, traditional TENGs typically output AC. Existing TENGs achieve DC output in four main ways: using a brush structure, employing phase design and a rectifier, utilizing the sliding Schottky nanocontact effect, and using electrostatic breakdown. TENGs using a brush structure to achieve DC output have a large peak factor (the ratio of peak value to root mean square value), resulting in low energy utilization efficiency. TENGs using phase design and a rectifier require sacrificing some energy to power the rectifier. Furthermore, the use of a rectifier further reduces the integration and conversion efficiency of the TENG. TENGs using the sliding Schottky nanocontact effect to achieve DC output generally have a small output and impose high requirements and limitations on the friction materials used in the experiments. Triboelectric nanogenerators that achieve DC output by employing coupled triboelectric effect and electrostatic breakdown effect are difficult to apply due to the severe wear of the triboelectric layer and the strictly controlled air gap between the collecting electrode and the triboelectric electrode.

[0003] Furthermore, existing DC triboelectric nanogenerators still suffer from wear issues related to the triboelectric materials. While methods such as non-contact, soft-contact, or automatic switching between contact and non-contact modes have been employed to improve the stability and durability of AC output triboelectric nanogenerators, research on improving the durability of DC output triboelectric nanogenerators is scarce.

[0004] Therefore, the present invention provides a DC triboelectric nanogenerator that is simple in principle, easy to manufacture, highly integrated, and has stable DC output, stable high voltage output, high stability and high durability. Summary of the Invention

[0005] Therefore, it is necessary to address the aforementioned technical problems by providing a DC triboelectric nanogenerator using steel needle electrodes and multi-element dielectric materials, its fabrication method, and its applications. This DC triboelectric nanogenerator is based on the principle of triboelectric generation using ternary dielectrics. By matching the electronegativity arrangement of the ternary triboelectric materials in space and fabricating a back electrode with steel needles, the triboelectric nanogenerator generates a constant and stable DC output and a constant and stable high-voltage output. It has the advantages of simple fabrication, high integration, constant DC output, constant and stable high-voltage output, high stability, and high durability. Furthermore, by using flexible dielectric materials, the triboelectric nanogenerator can generate DC output and maintain 100% output even after 100,000 cycles. In addition, it is simple to fabricate; without rectifier components, brush structures, sliding Schottky nano-contact effects, or electrostatic breakdown effects, the triboelectric nanogenerator possesses a constant DC voltage of 3 kV, a charge output of 9.807 millicoo per square meter, and an average power output of 32.121 watts per square meter. Furthermore, this DC triboelectric nanogenerator can be driven by winds of 1.8-3.6 meters per second, and the ultra-high energy it generates can be used to power sensor networks and electronic devices.

[0006] According to a first aspect of the present invention, a method for fabricating a DC triboelectric nanogenerator employing steel needle electrodes and a multi-element dielectric material is provided, comprising the following steps: cutting an acrylic sheet of thickness D into cubes with side length L, and using the cubes as the first substrate of component A; alternately engraving n first rectangular grooves of width w1 and length l1 on one side of the cube, where l1≤L, the spacing between two adjacent first rectangular grooves is 2w+w2, and the first rectangular grooves located at the ends are aligned with the edge of the first substrate. The spacing between them is w, where the length L satisfies the following relationship: L=n×w1+n×w2+(n+1)×w. The four corners of each first rectangular groove are chamfered. After chamfering, m holes with a diameter of r are made inside the first rectangular groove. Vertically, the center-to-center distance between adjacent rows of holes is l2, and horizontally, the center-to-center distance between adjacent columns of holes is l3. A steel needle of length l and diameter r is inserted into each hole. After insertion... Afterwards, silver paste is uniformly sprayed into each first rectangular groove, and the steel needles and silver paste are connected to form a negative output terminal, resulting in a back electrode with steel needles. A triboelectric material 2 with a thickness of t and t>l is pasted onto the back electrode with steel needles, and n second rectangular grooves with a width of w2 and a length of l1 are alternately engraved on the triboelectric material 2. The distance between two adjacent second rectangular grooves is 2w+w1, and the distance between the second rectangular groove at the end and the edge of the first substrate is w. An aluminum foil is pasted inside the second rectangular groove and connected with wires to form a positive output terminal. After pasting the aluminum foil, triboelectric material 1 is pasted onto the second rectangular groove to obtain component A. An acrylic plate with a thickness of D is cut into a rectangle with a length of L1 and a width of W, where L+l1≤L1 and L≤W. The rectangle is used as the second substrate of component B, and triboelectric material 3 is pasted onto the second substrate to obtain component B. Component A and component B are assembled in a horizontal sliding mode to obtain a DC triboelectric nanogenerator.

[0007] According to a first aspect of the present invention, a method for fabricating a DC triboelectric nanogenerator using steel needle electrodes and a multi-element dielectric material is also provided, comprising the following steps: cutting an acrylic plate of thickness D into a disk with an outer diameter D2 and an inner diameter d1, and using the disk as a first substrate of component A; engraving n first sector-shaped grooves with an outer diameter D1 and an inner diameter d2 on the surface of the disk, wherein the central angle of the first sector-shaped groove is a1, the spacing between two adjacent first sector-shaped grooves is equal, and the spacing between two adjacent first sector-shaped grooves is... The central angle is a2, a2>a1, where a1 and a2 satisfy the following relationship: (a1+a2)×n=360°; and the four corners of each first sector groove are chamfered. After the chamfering is completed, m holes with a diameter of r are opened inside each first sector groove. In the vertical direction, the center distance between two adjacent rows of holes is l2, and in the horizontal direction, the center distance between two adjacent columns of holes is l3; a steel needle with a length of l and a diameter of r is inserted into each hole, and the insertion process is... After completion, silver paste is evenly sprayed into each first sector groove, and the steel needle and silver paste are connected to form a negative output terminal, resulting in a back electrode with steel needles. A triboelectric material 2 of thickness t, where t > 1, is pasted onto the back electrode with steel needles. n second sector grooves with a central angle of a1 are engraved on the triboelectric material 2. The spacing between two adjacent second sector grooves is equal, and the central angle between two adjacent second sector grooves is a2, where a2 > a1. Here, a1 and a2 satisfy the following relationship: (a1 + ... (a2)×n=360°, a layer of aluminum foil is pasted inside the second sector groove and connected with wires to form the positive output terminal; after pasting the aluminum foil, triboelectric material 1 is pasted on the second sector groove to obtain component A; an acrylic plate with thickness D is cut into a disk with an outer diameter of D2 and an inner diameter of d1, and the disk is used as the second substrate of component B. Triboelectric material 3 is pasted on the second substrate to obtain component B; the obtained component A and component B are assembled in a rotation mode to obtain a DC triboelectric nanogenerator.

[0008] According to a second aspect of the present invention, a DC triboelectric nanogenerator employing steel needle electrodes and a multi-element dielectric material is also provided, which is fabricated by the aforementioned method.

[0009] In some optional implementations of certain embodiments, the DC triboelectric nanogenerator comprises component A and component B. Component A includes at least one constituent unit, with each constituent unit arranged alternately to form component A. Each constituent unit consists of a triboelectric dielectric material 1 with a back electrode and a triboelectric dielectric material 2 with a back electrode having a steel needle. The back electrodes of the triboelectric dielectric material 1 are connected to form a positive output terminal, and the back electrodes of the triboelectric dielectric material 2 are connected to form a negative output terminal. A DC output is formed between the positive and negative output terminals. Triboelectric dielectric material 3 is attached to the side of component B facing component A. The electronegativity relationship of the triboelectric dielectric material 1, triboelectric dielectric material 2, and triboelectric dielectric material 3 is as follows: electronegativity of triboelectric dielectric material 2 < electronegativity of triboelectric dielectric material 3 < electronegativity of triboelectric dielectric material 1.

[0010] In some alternative implementations of some embodiments, the triboelectric material 1 is one of polytetrafluoroethylene film, fluoroethylene propylene copolymer, and polyimide.

[0011] In some alternative implementations of some embodiments, the triboelectric material 2 is one of polyurethane foam, nylon film, rabbit hair, or paper.

[0012] In some alternative implementations of some embodiments, the triboelectric material 3 is one of polyester fiber wool, organic polymer materials, and grease.

[0013] According to a third aspect of the invention, an application of a DC triboelectric nanogenerator employing steel needle electrodes and multi-element dielectric materials is provided, the DC triboelectric nanogenerator being used to drive applications in sensor networks and electronic devices.

[0014] In some alternative implementations of certain embodiments, the DC triboelectric nanogenerator is used in applications such as distance sensors.

[0015] The advantages and beneficial effects of this invention are as follows: This invention provides a DC triboelectric nanogenerator using steel needle electrodes and multi-element dielectric materials, its fabrication method, and its application. By controlling the electronegativity of the triboelectric material and fabricating a back electrode with steel needles, a constant and stable DC output and a constant and stable high-voltage output of the triboelectric nanogenerator can be achieved. Furthermore, this invention controls the ternary triboelectric materials of the triboelectric nanogenerator to be arranged in space according to their electronegativity, forming a ternary triboelectric effect. Additionally, by embedding electrodes with steel needles on the back electrode of the triboelectric material 2, a field emission effect is formed, allowing the charge to circulate unidirectionally within the triboelectric nanogenerator, thus outputting a stable high-voltage DC signal. Simultaneously, by selecting a triboelectric material 3 made of soft material, a soft contact mode can be formed in the DC triboelectric nanogenerator, thereby enabling the DC triboelectric nanogenerator to have a stable output, superior power output capability, and stability, while further reducing wear and improving durability. In addition, when combined with a wind cup, this triboelectric nanogenerator can generate ultra-high energy output after harvesting wind energy, which can be used to drive electronic devices and sensor networks, further expanding the application of triboelectric nanogenerators in energy harvesting and self-powered sensing. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of component A in Embodiment 1 of the present invention.

[0017] Figure 2 This is a schematic diagram of component B in Embodiment 1 of the present invention.

[0018] Figure 3 This is a schematic diagram of the structure of the first rectangular groove in Embodiment 1 of the present invention.

[0019] Figure 4 This is a schematic diagram of the structure of the second rectangular groove in Embodiment 1 of the present invention.

[0020] Figure 5 This is a schematic diagram illustrating the working principle of the DC triboelectric nanogenerator before the charge on the dielectric layer reaches saturation in Embodiment 1 of the present invention.

[0021] Figure 6 This is a schematic diagram illustrating the working principle of a DC triboelectric nanogenerator after the charge on the dielectric layer reaches saturation in Embodiment 1 of the present invention.

[0022] Figure 7 This is an output diagram of the horizontally sliding DC triboelectric nanogenerator in Embodiment 1 of the present invention; wherein, Figure 7 (a) Comparison of leakage current of 2 mm polyurethane foam with 1.5 mm steel needle inserted and 2 mm polyurethane foam without steel needle inserted. Figure 7(b) The charge output of the horizontal sliding DC triboelectric nanogenerator at different sliding speeds; Figure 7 (c) shows the current output of the horizontal sliding DC triboelectric nanogenerator at different sliding speeds.

[0023] Figure 8 This is a schematic diagram of the structure of the first sector groove in Embodiment 2 of the present invention.

[0024] Figure 9 This is a schematic diagram of the structure of the second sector groove in Embodiment 2 of the present invention.

[0025] Figure 10 This is a schematic diagram of the DC triboelectric nanogenerator in Embodiment 2 of the present invention.

[0026] Figure 11 This is an output diagram of the rotary DC triboelectric nanogenerator in Embodiment 2 of the present invention; wherein, Figure 11 (a) is a charge output diagram of a rotating DC triboelectric nanogenerator at different rotation speeds after one revolution; Figure 11 (b) is a voltage output diagram of the rotary DC triboelectric nanogenerator at different rotational speeds; Figure 11 (c) shows the current output of the rotary DC triboelectric nanogenerator at different rotational speeds; Figure 11 (d) Current density output and power density output of a rotating DC triboelectric nanogenerator.

[0027] Figure 12 The figure shows the results of the stability test of the DC triboelectric nanogenerator in Embodiment 2 of the present invention.

[0028] Figure 13 These are scanning electron microscope (SEM) images of the polyurethane foam and polyester fiber fibers before and after the stability test in Example 2 of this invention; wherein, Figure 13 (a) is a scanning electron microscope image of the polyurethane foam before the stability test; Figure 13 (b) is a scanning electron microscope image of the polyurethane foam after the stability test; Figure 13 (c) is a scanning electron microscope image of polyester fiber fibers before the stability test; Figure 13 (d) is a scanning electron microscope image of polyester fiber wool after the stability test.

[0029] Figure 14 This is a performance output diagram of the rotary DC triboelectric nanogenerator used in Embodiment 3 of the present invention for collecting wind energy; wherein, Figure 14 (a) is a schematic diagram of a rotary DC triboelectric nanogenerator collecting wind energy; Figure 14 (b) is a schematic diagram of a rotary DC triboelectric nanogenerator that lights 3,714 LED lights by collecting wind energy; Figure 14 (c) is a schematic diagram of a rotary DC triboelectric nanogenerator that drives 50 thermometers and hygrometers by collecting wind energy. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0031] Example 1

[0032] Reference Appendix Figure 1-4 This embodiment proposes a method for fabricating a DC triboelectric nanogenerator using steel needle electrodes and multi-element dielectric materials. The method includes: cutting an acrylic sheet of thickness D into cubes with side length L, and using these cubes as the first substrate of component A; alternately engraving n first rectangular grooves with width w1 and length l1 on one side of the cube, where l1 ≤ L, and the spacing between two adjacent first rectangular grooves is 2w + w2; and defining the first rectangular groove at the end between the first rectangular groove and the edge of the first substrate. The spacing is w, where the length L satisfies the following relationship: L=n×w1+n×w2+(n+1)×w. The four corners of each first rectangular groove are chamfered. After chamfering, m holes of diameter r are made inside the first rectangular groove. Vertically, the center-to-center distance between adjacent rows of holes is l2, and horizontally, the center-to-center distance between adjacent columns of holes is l3. A steel needle of length l and diameter r is inserted into each hole. After insertion... Silver paste is uniformly sprayed into each first rectangular groove, and steel needles are connected to the silver paste to form a negative output terminal, thus obtaining a back electrode with steel needles. A triboelectric material 2 with a thickness of t and t>l is pasted on the back electrode with steel needles, and n second rectangular grooves with a width of w2 and a length of l1 are alternately engraved on the triboelectric material 2. The distance between two adjacent second rectangular grooves is 2w+w1, and the distance between the second rectangular groove at the end and the edge of the first substrate is w. An aluminum foil is pasted inside the second rectangular groove and connected with wires to form a positive output terminal. After pasting the aluminum foil, triboelectric material 1 is pasted on the second rectangular groove to obtain component A. An acrylic plate with a thickness of D is cut into a rectangle with a length of L1 and a width of W, where L+l1≤L1 and L≤W. The rectangle is used as the second substrate of component B, and triboelectric material 3 is pasted on the second substrate to obtain component B. Component A and component B are assembled in a horizontal sliding mode to obtain a DC triboelectric nanogenerator.

[0033] In this embodiment, the horizontal sliding mode mainly includes a slider (component A) and a plate (component B). Specifically, component A slides on component B, which is fixedly mounted on a base. In the assembled DC triboelectric nanogenerator, component A moves relative to component B, and the triboelectric material 3 is required to rub against triboelectric material 2 immediately after rubbing against triboelectric material 1 (or triboelectric material 3 rubs against triboelectric material 1 immediately after rubbing against triboelectric material 2). Therefore, triboelectric material 1 and triboelectric material 2 are always relatively stationary.

[0034] Furthermore, the DC triboelectric nanogenerator is composed of component A and component B. Component A includes at least one constituent unit, with each constituent unit arranged alternately to form component A. Each constituent unit consists of a triboelectric dielectric material 1 with a back electrode and a triboelectric dielectric material 2 with a back electrode having a steel needle. The back electrodes of the triboelectric dielectric material 1 are connected to form a positive output terminal, and the back electrodes of the triboelectric dielectric material 2 are connected to form a negative output terminal. A DC output is formed between the positive and negative output terminals. Triboelectric dielectric material 3 is attached to the side of component B facing component A. The electronegativity relationship of the triboelectric dielectric material 1, triboelectric dielectric material 2, and triboelectric dielectric material 3 is as follows: electronegativity of triboelectric dielectric material 2 < electronegativity of triboelectric dielectric material 3 < electronegativity of triboelectric dielectric material 1.

[0035] It should be understood that the choice of ternary tribological materials in this invention is not limited; any ternary tribological material can be used, as long as the ternary tribological materials have different electronegativity. The triboelectric dielectric material 3 (electroneutral material) is disposed on component B, and the triboelectric dielectric material 1 (electrone material) and triboelectric dielectric material 2 (electropositive material) are alternately attached to the electrodes of component A. This allows the device composed of ternary tribological materials to exhibit a decreasing electronegativity in space during operation, thereby enabling electron transfer within the ternary tribological materials. Simultaneously, a steel needle is embedded on the back electrode of the triboelectric dielectric material 2 (electropositive material), the length of which is less than the thickness of the electropositive material. This increases the leakage current of the electropositive material, thereby enabling electron tunneling within the dielectric material. The steel needle can also be made of a conductive material with a pointed structure; this is not limited here. Therefore, the morphology of the ternary triboelectric material is not fixed. Triboelectric material 1 (electrone material) can be made of materials with strong electronegativity such as polytetrafluoroethylene (PTFE), fluorinated ethylene propylene (FEP), and polyimide (kapton). Triboelectric material 2 (electropositive material) can be made of materials with strong electronegativity such as polyurethane foam, nylon film, rabbit hair, and paper. For triboelectric material 3 set on component B, its electronegativity is between that of triboelectric material 1 and triboelectric material 2, and it can be made of electrically neutral materials such as polyester fiber wool, organic polymer materials, and grease.

[0036] Preferably, the triboelectric material 1 is a polytetrafluoroethylene film.

[0037] Preferably, the triboelectric material 2 is polyurethane foam.

[0038] Preferably, the triboelectric material 3 is made of polyester fiber wool.

[0039] In this embodiment, the working principle of the triboelectric nanogenerator fabricated by this method includes both the working principle before the charge on the triboelectric layer reaches saturation and the working principle after the charge on the triboelectric layer reaches saturation. The working principle of the DC triboelectric nanogenerator fabricated by this method is explained here using the horizontal sliding mode. The working principle of other modes (i.e., rotational modes) of DC triboelectric nanogenerator fabricated using this method is similar. The specific working principle is as follows: A two-dimensional planar schematic diagram of the DC triboelectric nanogenerator is shown below. Figure 5 As shown in Figure a, it comprises a total of 8 components: 2 substrates, a soft buffer layer (the triboelectric material 2 used in this invention serves as the buffer layer), triboelectric material 1, triboelectric material 2, triboelectric material 3, a back electrode with steel pins attached to the back of triboelectric material 2, and a back electrode attached to the back of triboelectric material 1.

[0040] Initial state: When the slider slides on the polyester fiber wool, the friction between the three friction layers causes the separation of positive and negative charges (stage I). Figure 5 b). Because the electronegativity of polyester fiber fibers (triboelectric material 3) is higher than that of polyurethane foam (triboelectric material 2), friction between them leads to the separation of positive and negative charges. Because the electronegativity of polytetrafluoroethylene (triboelectric material 1) is higher than that of polyester fiber fibers (triboelectric material 3), friction between them also leads to the separation of positive and negative charges. As the slider continues to slide forward (stage II, Figure 5 c) First, before the PTFE and nylon membranes interact with the polyester fiber fur, the back electrodes of the PTFE and polyurethane foam induce opposite positive and negative charges due to electrostatic induction. The potential difference between the back electrodes causes the positive charge on the back electrode of the polyurethane foam to flow to the back electrode of the PTFE, forming a DC output in the external circuit. Then, the PTFE and polyurethane foam interact with the polyester fiber fur separately (Stage III). Figure 5 d). Therefore, the polyester fiber fur, after being rubbed with the nylon membrane, is then rubbed with the nylon membrane again. During this process, electrons are "transferred" from the polyester fur to the polytetrafluoroethylene (PTFE). At this point, a "charge transfer" occurs between the PTFE and the polyester fiber fur, while the polyurethane foam continues to generate triboelectric charge due to friction with the polyester fiber fur. Then, the back electrodes of the PTFE and polyurethane foam induce opposite positive and negative charges due to electrostatic induction. The potential difference between the back electrodes causes the positive charge on the back electrode of the polyurethane foam to flow to the back electrode of the PTFE, forming a DC output in the external circuit until the charge on the friction material reaches saturation (Stage IV). Figure 5 e).

[0041] After the dielectric layer reaches charge saturation, the working mechanism of the DC triboelectric nanogenerator is as follows: Figure 6 After the charge on the dielectric layer reaches saturation, a large amount of charge will be induced on the back electrodes of triboelectric material 1 (polytetrafluoroethylene) and triboelectric material 2. The steel needles on the back electrode of triboelectric material 2 (polyurethane foam in this application) will cause a large amount of electron tunneling between the material and the back electrode, triggering a field emission effect. This will cause a sharp increase in the leakage current of the polyurethane foam, resulting in charge leakage between the polytetrafluoroethylene and polyurethane foam and the back electrode (stage I). Figure 6 This neutralizes the charges on the PTFE and polyurethane foam. Then, the slider slides to the right, and the PTFE and polyurethane foam rub against the polyester fiber fibers, generating triboelectric charging and producing a large amount of triboelectric charge on their surfaces (Stage II). Figure 6Immediately afterwards, the slider continues to slide to the right, and the back electrodes of the PTFE and polyurethane foam induce opposite positive and negative charges due to electrostatic induction. The potential difference between the back electrodes causes the positive charge on the back electrode of the polyurethane foam to flow to the back electrode of the PTFE, forming a DC output in the external circuit (Stage III). Figure 6 At this point, the accumulated charge on the back of the dielectric material and the steel needles on the polyurethane foam back electrode cause charge leakage to occur again, resulting in the charge on the two triboelectric dielectric materials being neutralized again (Stage IV). Figure 6 Subsequently, the PTFE on the slider moves to the top of the polyester fiber fibers that had just been rubbed against the polyurethane foam. At this point, triboelectric charging ("charge transfer") occurs between the PTFE and the polyester fiber fibers, and triboelectric charging (stage V) occurs between the polyurethane foam and the polyester fiber fibers. Figure 6 Following this, the device continues to slide forward, and the triboelectric charge on the dielectric material causes electrostatic induction again on the back electrode, generating induced charge and forming a DC output in the external circuit (Stage VI). Figure 6 Then, the device cycles through the above 6 steps to generate a constant DC output in the external circuit.

[0042] To demonstrate the stable DC output and soft-contact mode of this invention, the output performance of the DC triboelectric nanogenerator was tested. During the testing, it was found that inserting a steel needle into the back electrode of the triboelectric material 2 significantly improved the leakage current of the triboelectric material 2. This structural arrangement is key to effectively improving the electrical output and integration of the DC triboelectric nanogenerator, which is completely different from the output of the AC triboelectric nanogenerator. Taking a two-unit DC triboelectric nanogenerator as an example, the leakage current of a 2 mm thick polyurethane foam was first tested. Figure 7 As shown in Figure a, when a 1.5 mm steel needle is embedded in the back electrode of a 2 mm thick polyurethane foam, its leakage current is 42.44 μA, which is 167% of that of polyurethane foam without the steel needle inserted. Subsequently, with the increase of sliding speed, the time for the 2-unit DC triboelectric nanogenerator to output 20 μC of DC charge decreases. Figure 7 b). In other words, the faster the sliding motion, the faster the charge accumulates, and therefore the greater the output current of the device. Figure 7 c).

[0043] Example 2

[0044] Reference Appendix Figure 8-10This embodiment proposes a method for fabricating a DC triboelectric nanogenerator using steel needle electrodes and multi-element dielectric materials. The method includes: cutting an acrylic plate of thickness D into a disk with an outer diameter D2 and an inner diameter d1, and using the disk as the first substrate of component A. The central hole of the first substrate is used to fix a steel rod passing through the motor. n first sector-shaped grooves with an outer diameter D1 and an inner diameter d2 are engraved on the surface of the disk, with a central angle of α1 and equal spacing between adjacent first sector-shaped grooves. The central angle between two adjacent first sector slots is a2, where a2 > a1, and a1 and a2 satisfy the following relationship: (a1 + a2) × n = 360°. Each first sector slot has its four corners chamfered. After chamfering, m holes with a diameter of r are made inside each first sector slot. Vertically, the center-to-center distance between two adjacent rows of holes is l2, and horizontally, the center-to-center distance between two adjacent columns of holes is l3. A [missing information - likely a device or instrument] of length l and diameter r is inserted into each hole. After the steel needles are inserted, silver paste is evenly sprayed into each first sector groove, and the steel needles and silver paste are connected to form a negative output terminal, resulting in a back electrode with steel needles. A triboelectric material 2 with a thickness of t and t>l is pasted on the back electrode with steel needles, and n second sector grooves with a central angle of a1 are engraved on the triboelectric material 2. The spacing between two adjacent second sector grooves is equal, and the central angle between two adjacent second sector grooves is a2, a2>a1, where a1 and a2 satisfy the following relationship: (a1+a2)×n=360°, a layer of aluminum foil is pasted inside the second sector groove and connected with wires to form the positive output terminal; after pasting the aluminum foil, triboelectric material 1 is pasted on the second sector groove to obtain component A; an acrylic plate with a thickness of D is cut into a disk with an outer diameter of D2 and an inner diameter of d1, and the disk is used as the second substrate of component B. Triboelectric material 3 is pasted on the second substrate to obtain component B; the obtained component A and component B are assembled in a rotation mode to obtain a DC triboelectric nanogenerator.

[0045] In this embodiment, the difference between the rotation mode and the horizontal sliding mode involved in Embodiment 1 is that the structures of component A and component B are different. In addition, the working principle of the DC triboelectric nanogenerator fabricated in this embodiment is similar to that of the DC triboelectric nanogenerator fabricated in Embodiment 1, and will not be described again here.

[0046] In this embodiment, the triboelectric material 1 is a polytetrafluoroethylene film, the triboelectric material 2 is polyurethane foam, and the triboelectric material 3 is polyester fiber wool.

[0047] In this embodiment, the rotation mode is used as the research object. When the rotation speed is 60 revolutions per minute, the output charge of the rotary DC triboelectric nanogenerator accumulates to 16.27 microcoulombs within 0.5 minutes. Figure 11 a) The charge density reaches 9.807 millicools per square meter. When the rotational speed changes, the voltage output of the DC triboelectric nanogenerator fluctuates slightly, but the fluctuation amplitude decreases and the voltage stabilizes at around 3000 volts. Figure 11 b). Simultaneously, the current output increases with increasing rotational speed. Figure 11 c). Whether it's charge output, current output, or voltage output, it exhibits typical steady DC output characteristics: the charge increases linearly, while the current and voltage remain constant as long as the rotational speed remains unchanged. At a rotational speed of 120 revolutions per minute, the device achieves an average power density of 32.121 watts per square meter with a matching impedance of 160 megohms. Figure 11 d).

[0048] In this embodiment, the stability of the DC triboelectric nanogenerator is tested using the rotation mode as the research object. Figure 12 As shown. During 100,000 cycles of testing, the rotary DC triboelectric nanogenerator maintained 100% charge output, further demonstrating its stable DC output characteristics. Simultaneously, scanning electron microscopy (SEM) images of the polyurethane foam and polyester fiber fibers were taken before and after the stability test, as shown below. Figure 13 As shown, the results revealed that prolonged operation did not cause significant material damage to the material surface. This is because the introduction of a soft dielectric material (such as polyester fiber wool) as the triboelectric material 3 enables the DC triboelectric nanogenerator to form a soft contact mode, which helps improve the output stability and reduce device wear.

[0049] Example 3

[0050] Reference Appendix Figure 14 This invention also proposes a wind cup for use in conjunction with the DC triboelectric nanogenerator prepared in Example 2. During assembly, component A, prepared in Example 2, is fixedly mounted on the wind cup and rotates with the wind cup on component B, which is fixedly mounted on a mounting base. By setting the wind cup, the DC triboelectric nanogenerator with high output and high stability can collect wind energy, such as... Figure 14 As shown in Figure a, by collecting wind energy at speeds of 1.8-3.6 meters per second, this device can be used to power electronic devices, such as driving 3712 LED lights. Figure 14 b) and 50 thermometers and hygrometers Figure 14 c).

[0051] Furthermore, by incorporating a wind cup, this triboelectric nanogenerator can harvest wind energy, generating ultra-high energy output to drive electronic devices and sensor networks, further expanding the applications of triboelectric nanogenerators in energy harvesting and self-powered sensing. Due to the ternary triboelectric effect and field emission effect, this triboelectric nanogenerator directly converts mechanical energy into DC electrical energy. In this process, there is no need for complex structural design or the consumption of triboelectric charge to cause electrostatic breakdown, effectively improving the conversion efficiency of mechanical energy by the triboelectric nanogenerator. This solves the problem of low energy conversion efficiency in existing AC triboelectric nanogenerators and greatly broadens the applications of DC triboelectric nanogenerators.

[0052] In summary, by matching the electronegativity of the triboelectric material and fabricating a back electrode with steel needles, a constant DC output and a constant high voltage output of the triboelectric nanogenerator can be achieved. Furthermore, introducing a soft dielectric material (such as polyester fiber wool) as the triboelectric material 3 enables the DC triboelectric nanogenerator to form a soft contact mode, thereby helping to improve output stability and reduce device wear.

[0053] The above description, in conjunction with specific embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such deductions or substitutions should be considered within the scope of protection of the present invention.

Claims

1. A method for fabricating a DC triboelectric nanogenerator using steel needle electrodes and multi-element dielectric materials, characterized in that, Includes the following steps: An acrylic sheet of thickness D is cut into cubes with a side length of L, and the cubes are used as the first substrate of component A. On one side of the cube, n first rectangular grooves with width w1 and length l1 are alternately engraved, and l1≤L. The distance between two adjacent first rectangular grooves is 2w+w2. The distance between the first rectangular groove at the end and the edge of the first substrate is w. The length of L satisfies the following relationship: L=n×w1+n×w2+(n+1)×w. The four corners of each first rectangular groove are chamfered. After the chamfering is completed, m holes with diameter r are opened inside the first rectangular groove. In the vertical direction, the center distance between two adjacent rows of holes is l2. In the horizontal direction, the center distance between two adjacent columns of holes is l3. A steel needle of length l and diameter r is inserted into each hole. After the insertion is completed, silver paste is evenly sprayed into each first rectangular groove. The steel needle and silver paste are connected to form a negative output terminal, thus obtaining a back electrode with steel needles. A triboelectric material 2 with a thickness of t is attached to the back electrode with steel needles, where t>l. Then, n second rectangular grooves with a width of w2 and a length of l1 are alternately engraved on the triboelectric material 2. The distance between two adjacent second rectangular grooves is 2w+w1. The distance between the second rectangular groove at the end and the edge of the first substrate is w. A layer of aluminum foil is attached inside the second rectangular groove and connected by wires to form a positive output terminal. After the aluminum foil is pasted, the triboelectric material 1 is pasted on the second rectangular groove to obtain component A; An acrylic sheet of thickness D is cut into a rectangle with length L1 and width W, where L+l1≤L1 and L≤W. The rectangle is used as the second substrate of component B. Triboelectric material 3 is attached to the second substrate to obtain component B. The obtained components A and B are assembled in a horizontal sliding mode to obtain a DC triboelectric nanogenerator.

2. A method for fabricating a DC triboelectric nanogenerator using steel needle electrodes and multi-element dielectric materials, characterized in that, Includes the following steps: An acrylic sheet of thickness D is cut into a disk with an outer diameter of D2 and an inner diameter of d1, and the disk is used as the first substrate of component A. n first sector-shaped grooves with outer diameter D1 and inner diameter d2 are engraved on the surface of a disk. The central angle of the first sector-shaped groove is a1. The distance between two adjacent first sector-shaped grooves is equal, and the central angle of the distance between two adjacent first sector-shaped grooves is a2, where a2>a1. Among them, a1 and a2 satisfy the following relationship: (a1+a2)×n=360°. The four corners of each first sector groove are chamfered. After the chamfering is completed, m holes with a diameter of l are opened inside each first sector groove. In the vertical direction, the center-to-center distance between two adjacent rows of holes is l2, and in the horizontal direction, the center-to-center distance between two adjacent columns of holes is l3. A steel needle of length l and diameter r is inserted into each hole. After the insertion is completed, silver paste is sprayed evenly into each first sector groove. The steel needle and silver paste are connected to form a negative output terminal, thus obtaining a back electrode with steel needles. A triboelectric material 2 of thickness t is attached to the back electrode with steel needles, where t>l. n second sector-shaped grooves with central angle a1 are engraved on the triboelectric material 2. The spacing between two adjacent second sector-shaped grooves is equal, and the central angle between the spacing between two adjacent second sector-shaped grooves is a2, where a2>a1. Here, a1 and a2 satisfy the following relationship: (a1+a2)×n=360°. A layer of aluminum foil is attached inside the second sector-shaped grooves and connected with wires to form a positive output terminal. After the aluminum foil is pasted, the triboelectric material 1 is pasted on the second sector groove to obtain component A; An acrylic sheet with a thickness of D is cut into a disk with an outer diameter of D2 and an inner diameter of d1. The disk is used as the second substrate of component B. Triboelectric material 3 is attached to the second substrate to obtain component B. The obtained components A and B are assembled in a rotational mode to obtain a DC triboelectric nanogenerator.

3. A DC triboelectric nanogenerator employing steel needle electrodes and multi-element dielectric materials, characterized in that, The DC triboelectric nanogenerator is manufactured by the method described in any one of claims 1 or 2.

4. A DC triboelectric nanogenerator using steel needle electrodes and multi-element dielectric materials according to claim 3, characterized in that, The DC triboelectric nanogenerator consists of component A and component B. Component A includes at least one constituent unit, with each constituent unit arranged alternately to form component A. Each constituent unit consists of a triboelectric dielectric material 1 with a back electrode and a triboelectric dielectric material 2 with a back electrode having a steel needle. The back electrodes of the triboelectric dielectric material 1 are connected to form a positive output terminal, and the back electrodes of the triboelectric dielectric material 2 are connected to form a negative output terminal. A DC output is formed between the positive and negative output terminals. Triboelectric dielectric material 3 is attached to the side of component B facing component A. The electronegativity relationship of the triboelectric dielectric material 1, triboelectric dielectric material 2, and triboelectric dielectric material 3 is as follows: electronegativity of triboelectric dielectric material 2 < electronegativity of triboelectric dielectric material 3 < electronegativity of triboelectric dielectric material 1.

5. A DC triboelectric nanogenerator using steel needle electrodes and multi-element dielectric materials according to claim 4, characterized in that, The triboelectric material 1 is one of polytetrafluoroethylene film, fluoroethylene propylene copolymer, and polyimide.

6. A DC triboelectric nanogenerator employing steel needle electrodes and multi-element dielectric materials according to claim 4, characterized in that, The triboelectric material 2 is one of polyurethane foam, nylon film, rabbit hair, or paper.

7. A DC triboelectric nanogenerator employing steel needle electrodes and multi-element dielectric materials according to claim 4, characterized in that, The triboelectric material 3 is one of polyester fiber wool and grease.

8. A DC triboelectric nanogenerator employing steel needle electrodes and multi-element dielectric materials according to any one of claims 3-7, for use in driving sensor networks and electronic devices.

9. The application according to claim 8, wherein the DC triboelectric nanogenerator is used in a distance sensor.

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