A friction nanogenerator based on inhibiting interface charge loss and improving maximum energy extraction of load voltage

Abstract

This invention discloses a triboelectric nanogenerator based on suppressing interfacial charge loss and improving the maximum energy extraction of load voltage. It includes a slider and a stator arranged vertically. The slider comprises a slider substrate (1) made of a rigid dielectric polymer material and an electronegative dielectric film (2) disposed on the upper side of the slider substrate (1). A left electrode (3) and a right electrode (4) are respectively disposed on the left and right sides of the stator. The stator comprises a stator substrate (5) made of a rigid dielectric polymer material, with an electropositive material (6) covering the upper side of the stator substrate (5). The slider is placed on the stator. The slider unit can be integrated by adding internal electrodes. The spacing between adjacent internal electrodes is 0.5mm-6mm. The thickness of the electropositive material (6) is greater than 0.5mm, and the thickness of the stator substrate (5) is greater than 1mm. This triboelectric generator is simple and flexible in design, has excellent output performance, low cost, and wide applicability, facilitating its practical application.

Description

Technical Field

[0001] This invention relates to the field of triboelectric nanogenerator technology, specifically a triboelectric nanogenerator based on suppressing interfacial charge loss and improving the maximum energy extraction of load voltage. Background Technology

[0002] Effective collection of interfacial triboelectric charge and increased load voltage are two crucial factors for improving the output energy density of triboelectric nanogenerators (TENGs). Currently, the mechanisms by which TENGs convert mechanical energy into electrical energy include electrostatic induction and corona discharge (CD). Among these, CD-TENGs can directly collect triboelectric charge for electrical output, exhibiting higher charge utilization efficiency and are considered an effective strategy for interfacial energy extraction. However, previous CD-TENG charge transfer mechanisms have been based on an ideal assumption: triboelectric charge is bound to the surface of the triboelectric material and collected by charge-collecting electrodes arranged on both sides of the slider. The potential distribution at the triboelectric interface and the process of interfacial charge loss are not well understood, making it difficult for CD-TENGs to maximize the collection of charge at the triboelectric interface. Furthermore, the contribution of load voltage to the TENG's output energy is as important as that of the output charge. To enhance the role of voltage in output energy, numerous studies have introduced contact switches and added insulating layers to increase electrode potential, significantly improving the output energy of TENGs, but also complicating their structure and reducing portability. In conclusion, developing a complete energy optimization route to reduce interfacial charge loss and increase load voltage is of great significance for advancing the practical application and commercialization of CD-TENGs. Summary of the Invention

[0003] To address the shortcomings of existing technologies, such as incomplete understanding of interfacial charge loss mechanisms and low load voltage of triboelectric nanogenerators (TENGs), this invention provides a triboelectric nanogenerator based on suppressing interfacial charge loss and increasing the maximum triboelectric interface energy extraction at the load voltage. By effectively suppressing interfacial charge loss and widening the spacing between internal electrodes to increase the load voltage, the output energy density of the CD-TENG is significantly improved.

[0004] To achieve the above objectives, the present invention is implemented through the following technical solution: a triboelectric nanogenerator based on suppressing interfacial charge loss and improving the maximum energy extraction of load voltage, comprising a slider and a stator arranged vertically, characterized in that: the slider comprises a slider substrate made of a rigid dielectric polymer material and an electronegative dielectric film disposed on the lower side of the slider substrate, and a left electrode and a right electrode are respectively disposed on the left and right sides of the stator.

[0005] The electronegative dielectric film has a thickness of 20-200 μm. The electronegative dielectric film is a single piece or divided into two or more small electronegative dielectric film pieces by adding internal electrode pairs. All electronegative dielectric film pieces are arranged side by side at intervals on the lower side of the slider substrate, and the gap between adjacent internal electrodes is 0.5 mm-6 mm.

[0006] The stator includes a rigid dielectric polymer stator substrate, the upper side of which is covered with an electropositive material, and the slider is placed on the stator.

[0007] The thickness of the electropositive material is greater than 0.5 mm, and the thickness of the stator substrate is greater than 1 mm.

[0008] The larger the spacing between the internal electrodes, the higher the potential of the electrodes under heavy load, and the better the output performance of the generator.

[0009] Specifically, when the electronegative dielectric film is divided into two or more electronegative dielectric film blocks, all electronegative dielectric film blocks are arranged side by side at intervals on the lower side of the slider substrate. The inner upper part of the electronegative dielectric film blocks on both sides (located on the edge) is provided with an inner electrode (the outer side is the left motor or right electrode). The upper part of both sides of the electronegative dielectric film block in the middle is provided with an inner electrode. The gap between the inner electrodes of adjacent electronegative dielectric film blocks is 0.5mm-6mm.

[0010] In the above scheme: the rigid dielectric polymer material is one of acrylic sheet, PVC sheet, PC sheet, ABS sheet, PVDF sheet, PP sheet, PE sheet, and POM sheet.

[0011] In the above scheme: the electronegative dielectric film (2) is one of PTFE film, FEP film, PVDF film, PVC film, PET film, and PVC film.

[0012] In the above scheme: the electronegative dielectric film is a PTFE film.

[0013] In the above scheme, the electropositive material is one of polyurethane foam, nylon, nitrile, and polyester.

[0014] In the above scheme: the electropositive material is polyurethane foam.

[0015] In the above scheme: the left electrode, the right electrode and the inner electrode are all metal material electrodes or non-metal electrodes, and the non-metal electrode is one of graphite electrode, conductive silicone electrode and conductive fabric electrode.

[0016] In the above scheme, the thickness of the electropositive material is 0.5mm-4mm. The thicker and higher the material, the better the generator's output performance.

[0017] In the above scheme, the thickness of the stator substrate is 1mm-6mm. The thicker and taller the substrate, the better the generator's output performance. When the thickness exceeds 6mm, the output remains essentially unchanged.

[0018] This invention relates to a corona discharge triboelectric nanogenerator (CD-TENG) based on suppressing interfacial charge loss and increasing load voltage. It reveals the mechanism of interfacial triboelectric charge loss, namely charge migration, bottom discharge, and interfacial breakdown, and provides an optimized scheme to suppress interfacial charge loss and increase its load voltage to maximize the output energy of the CD-TENG. Taking a single-unit slider CD-TENG as an example (the electronegative dielectric film 2 of the slider is not separated, such as...), Figure 1 As shown on the left side, after the slider rubs against the stator, the surface of the electronegative dielectric film 2 covering the slider carries a negative charge 7, and the surface of the electronegative material 6 covering the stator carries a positive charge 8. As the slider continues to move to the right, the left electrode 3 and right electrode 4 collect the positive charge on the surface of the electronegative material and the negative charge on the surface of the electronegative dielectric film, respectively. Since positive and negative charges are generated simultaneously during triboelectric charging, after the left and right electrodes collect the charges, the potential inside the friction layer will form a quasi-dipole distribution. That is, the accumulation of residual negative charge on the left side will form a negative potential 9, and the accumulation of residual positive charge on the right side will form a positive potential 10.

[0019] The quasi-dipole potential distribution proposed in this invention reveals the potential distribution within the interface of the CD-TENG friction layer. When the slider slides to the right, the left side of the friction interface exhibits a negative potential, while the right side exhibits a positive potential. The mover slides relative to the stator, which can be either fixed or movable. The length of the stator should be greater than the length of the slider to ensure the slider slides on the stator surface.

[0020] The quasi-dipole distributed potential moves synchronously with the slider, and when the slider moves in the opposite direction, the positive and negative values ​​of the potentials on the left and right sides also switch accordingly.

[0021] The quasi-dipole distribution potential at the interface induces three triboelectric charge loss processes. For ease of understanding, we use... Figure 2Figure a illustrates the principle of CD-TENG moving from left to right. ① Charge migration: The quasi-dipole potential induces charge migration from the electropositive material 6 and the stator substrate 5 to the friction interface, where it neutralizes the triboelectric charge during the dynamic operation of the CD-TENG. ② Bottom discharge: The interface quasi-dipole potential polarizes the friction layer 6 and the rigid substrate 5, causing electric dipoles to align from top to bottom along the friction layer and substrate. The electric dipoles at the bottom of the substrate can be equivalent to positive (right) and negative (left) bound charges on the surface. A strong electric field is formed at the bottom of the stator substrate 5. When the electric field strength exceeds the air breakdown threshold, air discharge is induced in the atmosphere, leading to the loss of interface triboelectric charge. ③ Interface breakdown: Since the quasi-dipoles maintain opposite potentials on the left and right sides of the friction interface, they establish a strong electric field in the middle of the friction layer, triggering air breakdown and resulting in the loss of triboelectric charge.

[0022] The interface triboelectric charge loss process can be optimized by various methods, including selecting a stator substrate 5 material to weaken charge migration, increasing the thickness of the stator substrate 5 to suppress bottom discharge caused by polarization, and adding internal electrodes with different logarithmic numbers to collect interface breakdown charge. After optimization using these strategies, the interface triboelectric charge is effectively collected.

[0023] The glow from the bottom discharge can be captured by a digital camera, and the discharge glow gradually weakens as the thickness of the stator substrate 5 increases.

[0024] The slider can be integrated into different units by adding internal electrodes of different logarithms, thereby improving the output performance of CD-TENG while keeping the total area of ​​the electronegative dielectric film 2 constant.

[0025] Beneficial Effects: This invention proposes a quasi-dipole potential model to describe the potential distribution within the CD-TENG interface. This model reveals the mechanisms of all triboelectric charge losses at the interface, namely charge migration, bottom discharge, and interface breakdown. Through material selection, increased material thickness, and internal electrode pair design, interface charge losses are progressively suppressed, significantly improving the generator's output charge. Furthermore, to address the low electrode potential of the CD-TENG, a potential difference enhancement strategy is proposed to increase its load voltage, achieving ultra-high output energy that can power various commercial electronic devices. This triboelectric generator is simple, flexible, low-cost, and exhibits excellent output performance, making it suitable for a wide range of applications. This invention provides important insights into the triboelectric charge loss process and potential difference enhancement mechanism, offering a comprehensive energy optimization roadmap. Attached Figure Description

[0026] Figure 1 Figure a is a schematic diagram of the structure of a unit slider CD-TENG provided by the present invention. Figure 1 In the diagram, 'a' represents a single-unit slider, 'b' represents a two-unit slider, and 'c' represents a four-unit slider.

[0027] Figure 2 , a is a mechanism diagram of the three triboelectric charge loss processes induced by the quasi-dipole potential inside the CD-TENG interface. Figure 2 In the diagram, d represents the optimized route for reducing interfacial triboelectric charge loss.

[0028] Figure 3 For different conductors, low leakage current and high leakage current rigid substrate CD-TENG short-circuit charge.

[0029] Figure 4 In the middle, a is a schematic diagram of the CD-TENG polarization-induced bottom discharge structure. Figure 4 In the figure, b represents the output charge of CD-TENG under polyurethane foam friction layers and acrylic substrates of different thicknesses.

[0030] Figure 5 Image a shows photos of the 1-unit and 6-unit CD-TENG sliders. Figure 5 b and Figure 5 c represents the output charge and output current of different CD-TENGs.

[0031] Figure 6 'a' is a mechanism diagram of charge loss between electrode pairs within a CD-TENG with more than 2 units under heavy load. Figure 6 b is a potential difference enhancement strategy to achieve high output energy of CD-TENG under heavy load. Figure 6 c represents the VQ curve of a 2-unit CD-TENG with different internal electrode gaps. Figure 6 d represents the output energy of a 6-unit CD-TENG under various loads. Figure 6 The output energy density of the CD-TENG is compared when the internal electrode gap is 2mm and 6mm. Figure 6 The output current, voltage, and average power density of a 6-unit CD-TENG (electrode gap of 6mm) under various external loads are shown.

[0032] Figure 7 The image shows a digital photograph of a 6-unit CD-TENG displaying 5568 green LEDs with a diameter of 5mm. Figure 7 b is a 6-unit CD-TENG digital photograph powered by 24 commercial thermometers and hygrometers. Detailed Implementation

[0033] Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0034] Example 1

[0035] A triboelectric nanogenerator based on suppressing interfacial charge loss and improving the maximum energy extraction of load voltage includes a slider and a stator arranged vertically. The length of the stator should be greater than the length of the slider to ensure that the slider slides on the surface of the stator.

[0036] The slider comprises a rigid dielectric polymer substrate 1, an electronegative dielectric film 2 disposed on the underside of the substrate 1, and a left electrode 3 and a right electrode 4 disposed on the left and right sides of the slider, respectively. The electronegative dielectric film 2 has a thickness of 20-200 μm and is either a single piece or divided into two or more smaller electronegative dielectric film pieces with additional inner electrode pairs. All the smaller electronegative dielectric film pieces are arranged side-by-side with spacing on the underside of the substrate 1, and the gap between adjacent inner electrodes is 0.5 mm-6 mm. Figure 1 The distance between inner electrode 11 and inner electrode 12 on the upper right side (the reference numerals 11 and 12 are only for ease of understanding the gap between the inner electrodes and do not represent two different components). Specifically, when there is only one electronegative dielectric film, there is no inner electrode. When the electronegative dielectric film is divided into two or more electronegative dielectric film blocks, all electronegative dielectric film blocks are arranged side by side at intervals on the lower side of the slider substrate. The inner upper part of the inner side of the electronegative dielectric film blocks on both sides (located on the edge) is provided with an inner electrode (the outer side is the left electrode or right electrode), and the upper part of both sides of the electronegative dielectric film block in the middle is provided with an inner electrode. The gap between the inner electrodes of adjacent electronegative dielectric film blocks is 0.5mm-6mm.

[0037] The stator includes a rigid dielectric polymer stator substrate 5, with an electropositive material 6 covering the upper side of the stator substrate 5. A slider is placed on the stator. The rigid dielectric polymer material is one of acrylic, PVC, PC, ABS, PVDF, PP, PE, or POM. The electronegative dielectric film 2 is one of PTFE, FEP, PVDF, PVC, PET, or PVC. The electropositive material is one of polyurethane foam, nylon, nitrile, or polyester. The left electrode, right electrode, and inner electrode are all metallic or non-metallic electrodes; the non-metallic electrode is one of graphite, conductive silicone, or conductive fabric.

[0038] The thickness of the electropositive material 6 is greater than 0.5 mm, preferably 0.5 mm to 4 mm. The thickness of the stator substrate 5 is greater than 1 mm, preferably 1 mm to 6 mm. The spacing between the inner electrode 11 and the inner electrode 12 is 0.5 mm to 6 mm.

[0039] Example 1: Interface charge loss mechanism and optimization strategy.

[0040] The slider substrate 1 is made of acrylic sheet, with dimensions of 40mm in length, 60mm in width, and 4mm in thickness. An electronegative polytetrafluoroethylene (PTFE) dielectric film, 150μm thick, is adhered to the surface of the acrylic substrate as the friction layer for the slider. Copper electrodes, each 30μm thick, are attached to both sides of the slider; the left electrode 3 and the right electrode 4 each have an area of ​​4×60mm². 2 The stator substrate 5 is an acrylic sheet with dimensions of 150mm in length, 70mm in width, and 1-7mm in thickness. The electropositive material 6 consists of positively charged polyurethane foam of varying thicknesses from 0.5mm to 4mm, which completely covers the surface of the stator substrate 5 as a friction layer for the stator. After contact friction electrification between PTFE and polyurethane foam, the PTFE surface becomes negatively charged, while the polyurethane foam surface becomes positively charged.

[0041] In this embodiment, during the electrical performance testing of the CD-TENG, a programmable linear motor is used to simulate external linear reciprocating mechanical energy motion. The left electrode 3 and right electrode 4 of the CD-TENG's charge collection are connected as output terminals to an electrometer (Keithley 6514) and a high-speed electrostatic voltmeter (Trek model 370) to test its output of transferred charge, short-circuit current, and open-circuit voltage.

[0042] like Figure 2 As shown in Figure a: When the CD-TENG moves from left to right, the left and right electrodes 3 and 4 of the slider collect positive charges on the surface of the polyurethane foam and negative charges on the surface of the PTFE dielectric film, respectively. Since positive and negative charges are generated simultaneously during triboelectric charging, residual charges accumulate in the friction layer after the left and right electrodes collect the charges, resulting in a quasi-dipole distribution of the potential within the friction layer. Specifically, the left side maintains a negative potential 9, while the right side forms a positive potential 10. Under the induction of this quasi-dipole distribution potential at the interface, three charge loss processes occur: ① Charge migration: The quasi-dipole potential induces charge migration from the polyurethane foam and stator substrate to the friction interface, where it neutralizes the triboelectric charge during the dynamic operation of the CD-TENG. ② Bottom discharge: The quasi-dipole potential at the interface polarizes the friction layer and stator substrate 5, causing the electric dipoles to arrange themselves orderly from top to bottom along the friction layer and substrate. The electric dipoles at the bottom of the stator substrate 5 can be equivalent to the positive (right) and negative (left) bound charges on the surface. A strong electric field is formed at the bottom of the stator substrate 5. When the electric field strength is greater than the air breakdown threshold, air discharge is induced in the atmosphere, resulting in the loss of interface triboelectric charge. ③ Interface breakdown: Since the quasi-dipoles maintain opposite potentials on the left and right sides of the triboelectric interface, they will establish a strong electric field in the middle of the triboelectric layer to trigger air breakdown, thereby causing the loss of triboelectric charge.

[0043] Figure 2b illustrates an optimized roadmap for reducing three types of triboelectric charge losses, including selecting stator substrates 5 with different leakage characteristics to weaken charge migration, increasing the thickness of stator substrate 5 to suppress bottom discharge caused by polarization, and designing internal electrodes to collect breakdown charges at the interface. First, charge migration is essentially a charge transfer within the material induced by a strong electric field. The strength of charge migration is closely related to the resistivity of the material, and the higher the resistivity, the weaker the charge migration. This invention tested the CD-TENG output charge of stator substrates 5 with different leakage characteristics, such as... Figure 3 (A single-unit CD-TENG (with only one electronegative dielectric film) is shown. Results show that the output charge of the low-leakage rigid substrate material is higher than that of the high-leakage rigid substrate material, and the output charge of the high-leakage rigid substrate material is higher than that of the conductor. Therefore, a low-leakage rigid material can be selected as the substrate for the CD-TENG to mitigate charge loss caused by charge migration. Second, due to the attenuation of the interfacial electric field in the material, the polarization field density decreases with increasing material thickness. Therefore, increasing the thickness of the stator substrate 5 and the polyurethane foam 6 can effectively suppress bottom discharge caused by polarization, thereby increasing the output charge of the CD-TENG, such as...) Figure 4 As shown in (Unit CD-TENG), the thickness of the stator substrate 5 increases from 1 mm to 6 mm, and the output charge increases from 0.31 μC to 2.02 μC. The thickness of the polyurethane foam 6 increases from 0.5 mm to 4 mm, and the output charge increases from 1.37 μC to 1.98 μC. Third, as... Figure 5 As shown in Figure a, CD-TENG integrates different slider units by adding internal electrodes 11 and 12 with different logarithmic numbers while keeping the total PTFE area constant. Figure 5 Figure a shows schematic diagrams of a 1-unit (without internal electrodes) and a 6-unit CD-TENG slider. Experimental results show that the integrated slider unit can effectively collect breakdown charge within the interface. Both its output charge and current increase with increasing integration logarithm, such as... Figure 5 As shown in b and c, all three strategies demonstrate the effectiveness of suppressing charge loss in improving the output charge of the CD-TENG.

[0044] Example 2: Potential difference enhancement strategy to improve the output energy of CD-TENG.

[0045] For CD-TENGs with two or more units, when the external load is a large resistance, a further increase in the discharge-limiting electrode potential will occur between the internal electrodes. Figure 6 (a) This invention proposes a potential difference enhancement strategy that increases the potential of the charge collection electrode by widening the gap between the internal electrode pairs of the CD-TENG, thereby increasing the output energy of the CD-TENG, such as... Figure 6As shown in b, taking the 2-unit slider CD-TENG as an example, when the internal electrode gap is increased from 0.5mm to 6mm, the short-circuit charge and current remain almost stable. Interestingly, its average power and output energy increase with the increase of the internal electrode gap. Figure 6 Figure c shows the VQ curve of a 2-unit CD-TENG with an external load of 1 GΩ. The results indicate that the enhanced output energy of the CD-TENG is due to the increase in load voltage and charge. Increasing the gap between the internal electrodes can significantly improve the potential difference threshold between charge collectors and reduce charge loss between the internal electrodes under heavy loads. Using this potential difference enhancement strategy, a 6-unit slider CD-TENG with an electrode gap of 6 mm was fabricated, and its output energy is as follows... Figure 6 As shown in d, the output energy reaches 24.17 mJ with an external load of 1 GΩ. Compared with the output energy density of a 6-unit CD-TENG with an electrode gap of 2 mm, the output energy density increases by 3.24 times. Figure 6 e). Furthermore, such as Figure 6 As shown in f, under an external load of 1 GΩ, the maximum output power density of the 6-unit CD-TENG with an internal electrode gap of 6 mm reaches 17.13 W / m². -2 Generally speaking, CD-TENGs with more slider units can achieve a higher maximum output power density.

[0046] Example 3: CD-TENG Driven Commercial Electronic Devices

[0047] The CD-TENG boasts excellent portability and output performance, and we demonstrate its practical applications based on these two aspects. For example... Figure 7 As shown in Figure a, a CD-TENG with a 6-unit slider and an internal electrode gap of 6 mm (contact area: 24 cm²) is manually driven. 2 The CD-TENG successfully lit up 5,568 LEDs with a diameter of 5mm, demonstrating its excellent portability. Figure 7 b shows the voltage-time curves and digital photos of 24 thermometers and hygrometers during operation. The 1mF capacitor was charged to 1.8V in 8.3s. After being connected to the thermometer and hygrometer, the voltage dropped rapidly to 1.6V and remained stable for about 150 seconds.

[0048] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A triboelectric nanogenerator based on suppressing interfacial charge loss and improving maximum energy extraction from load voltage, comprising a slider and a stator arranged vertically, characterized in that: The slider includes a slider substrate (1) made of hard dielectric polymer material, an electronegative dielectric film (2) disposed on the lower side of the slider substrate (1), and a left electrode (3) and a right electrode (4) disposed on the left and right sides of the stator, respectively. The electronegative dielectric film (2) has a thickness of 20-200 μm. The electronegative dielectric film (2) is divided into two or more electronegative dielectric film blocks by adding internal electrode pairs. All electronegative dielectric film blocks are arranged side by side at intervals on the lower side of the slider substrate (1). The gap between adjacent internal electrodes is 0.5 mm-6 mm. The stator includes a rigid dielectric polymer stator substrate (5), the upper side of which is covered with an electropositive material (6), and the slider is placed on the stator; the rigid dielectric polymer material is one of acrylic sheet, PVC, PC, ABS, PVDF, PP, PE, and POM; the electronegative dielectric film (2) is one of PTFE film, FEP film, PVDF film, PVC film, PET film, and PVC film; The electropositive material is one of polyurethane foam, nylon, nitrile, and polyester. The left electrode, right electrode and inner electrode are all metal electrodes or non-metal electrodes. The non-metal electrode is one of graphite electrode, conductive silicone electrode and conductive fabric electrode. The thickness of the electropositive material (6) is 0.5mm-4mm and the thickness of the stator substrate (5) is 1mm-6mm.

2. The triboelectric nanogenerator based on suppressing interfacial charge loss and improving maximum energy extraction from load voltage according to claim 1, characterized in that: The electronegative dielectric film is a PTFE film.

3. The triboelectric nanogenerator based on suppressing interfacial charge loss and improving maximum energy extraction from load voltage according to claim 2, characterized in that: The electropositive material is polyurethane foam.

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