Flow core nanoflower / polymer composite fiber membranes, triboelectric electrodes, triboelectric devices, and preparation and application thereof

Abstract

The application belongs to the field of functional materials, and particularly relates to a flow core nanoflower / polymer composite fiber membrane, a triboelectric electrode, a triboelectric device and preparation and application thereof. The flow core nanoflower / polymer composite fiber membrane is a fiber membrane material formed by interlacing and weaving of functional nanofibers. The functional nanofibers include polymer fibers and flow core nanoflowers dispersedly distributed in the polymer fibers. The polymer in the polymer fibers is a positive polymer or a negative polymer. The flow core nanoflower is a flower-shaped nanoparticle, which includes a gallium-indium composite oxide shell with a corrugated surface and a gallium-indium alloy core in a flow state filled in the shell. The application innovatively disperses the nanoflowers with a special flow core structure in the polymer fibers, so that the interface adaptability of the material can be changed, the application requirements of the triboelectric device can be met, and the triboelectric performance can be improved.

Description

Technical Field

[0001] This invention belongs to the field of new functional materials, specifically relating to the field of triboelectric device technology. Background Technology

[0002] With rapid societal development, the ecological and maintenance costs associated with traditional batteries are increasingly severe, necessitating the development of a green and safe new energy system. In recent years, energy conversion technologies that extract renewable energy from the environment, such as mechanical, thermal, and solar energy, and convert it into sustainable electrical energy have been widely recognized as one of the most promising solutions. Consequently, several common energy conversion devices—piezoelectric devices, triboelectric devices, and pyroelectric devices—have been developed based on the piezoelectric effect, triboelectricity, electrostatic induction, and the Soret effect. Among these, triboelectric devices are highly competitive due to their significant advantages, including diverse material choices, high power density, stable output, and environmental friendliness. Triboelectric devices, based on triboelectric and electrostatic induction effects, can convert irregular, high-entropy, low-frequency, and abundant mechanical energy in the environment into electrical energy, effectively promoting the development of self-powered sensors, personal health monitoring, electronic skin, and wearable emergency power supplies. Furthermore, compared to other energy conversion devices, triboelectric devices, with their high efficiency and low-frequency distributed energy conversion characteristics, have enormous potential to power distributed devices or be integrated into self-powered systems, further meeting the urgent needs of the rapidly developing Internet of Things and artificial intelligence for distributed energy harvesting devices.

[0003] Self-powered systems based on triboelectric devices have demonstrated excellent application value in fields such as intelligent electronic devices and self-powered sensing. For example, existing technology has developed a coaxial, stretchable Ecoflex / ZnS and carbon nanotube fiber electrode, which serves as a self-powered triboelectric device fiber. This mechanoluminescent triboelectric nanogenerator fiber exhibits excellent tensile properties, maintaining stable functionality even under strains up to 200%, and can respond to visual and digital signals generated by mechanical stimuli through electrical output signals. This device demonstrates superior performance in non-contact sensing, showcasing important applications including health monitoring, pressure sensing, smart zithers, alarms, and collision avoidance. Furthermore, its unique underwater sensing and rescue applications, as well as optoelectronic synergistic applications, demonstrate its versatility in addressing imperceptibility, facilitating information exchange, and supporting rescue operations.

[0004] The rapid development of the Internet of Things (IoT) and artificial intelligence (AI) has led to a demand for distributed sensors and environmental pollution problems caused by frequent battery replacements. Triboelectric devices can convert irregular, low-frequency, and abundant mechanical energy in the environment into electrical energy, thus showing promise as an emerging technology to solve future energy needs. Triboelectric devices have advantages such as diverse material selection, simple manufacturing processes, easy integration, and low cost, making self-powered systems developed based on them promising for broad applications.

[0005] Currently, triboelectric devices generally have high output voltages but relatively low output currents, and their electromechanical conversion capabilities often depend on significant external forces. Therefore, the application scenarios for self-powered devices constructed from them are limited. Thus, there is an urgent need to modify existing triboelectric materials and innovate the structural design of triboelectric devices to prepare highly sensitive, high-output, and interference-resistant self-powered devices. Summary of the Invention

[0006] In view of the problems existing in existing triboelectric devices, the primary objective of this invention is to provide a flowing nanoflower / polymer composite fiber membrane, which aims to prepare a membrane material suitable for electrodes of triboelectric devices.

[0007] The second objective of this invention is to provide a method for preparing the aforementioned flowing nanoflower / polymer composite fiber membrane.

[0008] A third objective of this invention is to provide a triboelectric electrode comprising the aforementioned flowing nanoflower / polymer composite fiber membrane.

[0009] The fourth objective of this invention is to provide a method for preparing the triboelectric electrode and its application in the preparation of triboelectric devices.

[0010] The fifth objective of this invention is to provide the aforementioned triboelectric device, its preparation, and its application.

[0011] A fluid nanoflower / polymer composite fiber membrane is a fiber membrane material made by interlacing and weaving functional nanofibers;

[0012] The functional nanofibers include polymer fibers and fluidized nanoflowers (also known as fluidized nanoparticles) dispersed therein.

[0013] The polymer in the polymer fiber is a positive polymer or a negative polymer;

[0014] The aforementioned flowing nanoflowers are flower-shaped nanoparticles, comprising a gallium-indium composite oxide shell with a wrinkled surface and a flowing gallium-indium alloy core filled within the shell.

[0015] This invention innovatively disperses nanoflowers with a special morphology in polymer fibers, thereby changing the interfacial compatibility of the material to meet the application requirements of triboelectric devices and improving triboelectric performance.

[0016] In this invention, the positive polymer includes at least one of nylon 6, nylon 11, nylon 66, and polyacrylonitrile (PAN).

[0017] The negative polymers include PVDF-based polymers; for example, they can be at least one of PVDF-TrFE, PVDF, PI, PVC, and PTFE.

[0018] The diameter of the fibers of negative polymers is 100~500nm.

[0019] The fiber diameter of the positive polymer is 200~600nm.

[0020] The particle size of the flowing nanoflower is 0.5~5μm; the thickness of the shell is 0.7~3nm.

[0021] In this invention, the flowing nanoflowers are distributed in the fiber matrix and / or embedded on the surface of the fiber.

[0022] In the composite fiber membrane, the content of flowing nanoflowers is 10~45 wt.%; more specifically, it can be 28~32 wt.%.

[0023] The composite fiber membrane has a porosity of 50~90 vol.% and a thickness of 1~500 μm.

[0024] This invention also provides a method for preparing the aforementioned flowing nanoflower / polymer composite fiber membrane, comprising the following steps:

[0025] Step 1:

[0026] A fluidized gallium-indium alloy was placed in an alcohol-containing aqueous solution and then subjected to cavitation treatment in an oxygen-containing atmosphere to form a gallium-indium composite oxide shell on the surface of the fluidized gallium-indium alloy, thereby obtaining the fluidized nanoflower.

[0027] The cavitation process involves a power of 100W to 500W and a duration of 7 to 9 hours.

[0028] Step 2:

[0029] The molten nanoflowers and polymers were slurried with a solvent to obtain a spinning solution, which was then subjected to electrospinning to obtain the molten nanoflower / polymer composite fiber membrane.

[0030] This invention innovatively involves cavitation treatment of fluidized gallium-indium alloy in an alcohol-containing aqueous solution and an oxygen-containing atmosphere. This allows for gas-solid-liquid three-phase exchange, in-situ oxidation, and the construction of an in-situ irregular flower-like composite oxide surface on the surface of the fluidized gallium-indium alloy with the assistance of cavitation. The research of this invention also shows that innovative spinning treatment with polymers can yield fiber films suitable for triboelectric device applications.

[0031] In this invention, the alcohol in the alcohol-containing aqueous solution includes at least one of methanol and ethanol.

[0032] The volume content of alcohol in the alcohol-containing aqueous solution is 10~80 vol.%; more specifically, it can be 40~60 vol.%.

[0033] The liquid-to-solid ratio of the alcohol-containing aqueous solution and the gallium-indium alloy is 10-50 mL / g; further, it can be 20-40 mL / g.

[0034] The oxygen content in the oxygen-containing atmosphere is 10-30%, and it can be further converted into air.

[0035] In this invention, a stabilizer is also added to the alcohol-containing aqueous solution, and the stabilizer includes PVP.

[0036] Preferably, the concentration of the stabilizer in the alcohol-containing aqueous solution can be 1~3 mg / mL.

[0037] In this invention, the cavitation process can be achieved using conventional ultrasonic equipment. Furthermore, the power of the cavitation process can be 250~350W.

[0038] In this invention, the solvent in the spinning solution is an organic solvent capable of dissolving the polymer, such as DMF, DMSO, NMP, etc.

[0039] In the spinning solution, the polymer concentration is 5-20 wt.%, and the concentration of the molten nanoflowers is 2-10 wt.%; further, the polymer concentration is 10-15 wt.%, and the concentration of the molten nanoflowers is 5-7 wt.%. At the preferred concentrations, process synergy can be further enhanced, and performance can be further improved.

[0040] The voltage for electrostatic methods is 15~20kV; the spacing is 10~15cm.

[0041] The present invention also provides a triboelectric electrode, comprising a fiber membrane and a conductive metal composite thereon; wherein the fiber membrane is the fluidized nanoflower / polymer composite fiber membrane described in the present invention.

[0042] In the fluidized nanoflower / polymer composite fiber membrane, the polymer is a positive polymer, and the corresponding triboelectric electrode is a positive electrode.

[0043] In the flowing nanoflower / polymer composite fiber membrane, the polymer is a negative polymer, and the corresponding triboelectric electrode is a negative electrode.

[0044] This invention combines a positive electrode and a negative electrode containing the fluidized nanoflower / polymer composite fiber membrane described herein. This method overcomes the problem of poor interfacial compatibility of traditional rigid solid fillers and significantly improves the electrical output performance of triboelectric devices by promoting the accumulation of triboelectric charge at the material interface and reducing the effective thickness. Therefore, the triboelectric electrode described in this invention can achieve high output performance under low external force conditions, effectively optimizing the electromechanical conversion capability of triboelectric devices.

[0045] In this invention, the conductive metal is disposed on one surface of the flowing nanoflower / polymer composite fiber membrane.

[0046] In this invention, a conductive metal can be laminated onto the surface of the molten nanoflower / polymer composite fiber membrane using known methods to obtain the triboelectric electrode. For example, as an optional approach, a conductive adhesive can be coated onto the surface of the molten nanoflower / polymer composite fiber membrane, followed by lamination with the conductive metal to obtain the triboelectric electrode.

[0047] The present invention also provides a triboelectric device, comprising a positive electrode (also referred to as a positive electrode) and a negative electrode (also referred to as a negative electrode), wherein the polymer surfaces (fiber membrane surfaces) of the positive electrode and the negative electrode are arranged opposite to each other, and a barrier layer or cavity is provided between the positive electrode and the negative electrode.

[0048] The positive electrode is the positive electrode of the present invention, and / or the negative electrode is the negative electrode of the present invention.

[0049] In this invention, the main difference from conventional triboelectric devices lies in the use of the positive and / or negative electrodes described in this invention, while other structural components and materials can be known.

[0050] Preferably, the positive electrode is the positive electrode of the present invention, and the negative electrode is the negative electrode of the present invention.

[0051] In this invention, the combination of the positive and negative electrodes described herein enables further synergy, which helps to further enhance the performance of the triboelectric device.

[0052] There is a cavity between the positive electrode and the negative electrode, and the two have an interlocking structure.

[0053] Preferably, the undulation angle of the interlocking structure is below 60°, and more preferably 20~40°. This invention demonstrates that, thanks to the combination of the positive and negative electrodes, along with the interlocking structure and the combined control of the undulation angle, the performance of the triboelectric device can be further synergistically improved.

[0054] The device described in this invention, apart from including the electrodes described in this invention, may have other known components and structural relationships.

[0055] The present invention also provides an application of the aforementioned triboelectric device for the fabrication of motion energy harvesting and / or gesture recognition sensors.

[0056] Beneficial effects

[0057] This invention innovatively disperses nanoflowers with a special morphology in polymer fibers, making them suitable for the application requirements of triboelectric devices and improving their triboelectric performance.

[0058] This invention combines the negative and positive electrodes, which further enhances the synergy between the electrodes and helps to improve the performance of the triboelectric device. Furthermore, by setting the positive and negative electrodes in an interlocking structure and controlling their undulation angle, the performance of the triboelectric device can be further improved synergistically. Attached Figure Description

[0059] Figure 1 The images shown are test images of the flow-core particles obtained in Example 1, where (a) is a secondary electron image of the flow-core particle, (b) is a secondary electron image of a single flow-core particle, (c) is an EDS image of the Ga element in the flow-core particle, and (d) is an EDS image of the In element in the flow-core particle.

[0060] Figure 2 The images shown are secondary electron images of PVDF-TrFE-based negative tribological materials with different contents of flowing nanoflowers in Example 2. Among them, (a) is the fiber image of group a; (b) is the fiber image of group b; (c) is the fiber image of group c; (d) is the fiber image of group d; (e) is the fiber image of group e; and (f) is the fiber image of group f.

[0061] Figure 3 The images shown are test results for PVDF-TrFE-based composite materials with different contents of flowing nanoflowers in Example 2. (a) is the XRD pattern, (b) is the characteristic peak of the β phase, (c) is the infrared spectrum, and (d) is the β phase content diagram.

[0062] Figure 4 The following are test results for PVDF-TrFE-based composite materials with different contents of flowing nanoflowers in Example 2. Among them, (a) is a graph showing the relationship between dielectric constant and frequency, (b) is a graph showing the dielectric constant value at 1 kHz, (c) is a graph showing dielectric loss, and (d) is a graph showing PE curve.

[0063] Figure 5The images shown are test diagrams of PVDF-TrFE-based composite materials with different contents of flowing nanoflowers in Example 2. (a) is a diagram of saturated polarization intensity and residual polarization intensity, and (b) is a diagram of breakdown field strength.

[0064] Figure 6 The following are surface potential diagrams of PVDF-TrFE-based composite materials with different contents of flowing nanoflowers in Example 2, where (a) is the surface potential diagram of group a; (b) is the surface potential diagram of group b; (c) is the surface potential diagram of group c; (d) is the surface potential diagram of group d; (e) is the surface potential diagram of group e; and (f) is the surface potential diagram of group f.

[0065] Figure 7 The images shown are secondary electron images of nylon 6-based positive tribological materials with different contents of flowing nanoflowers in Example 3. Among them, (a) is the fiber image of group a; (b) is the fiber image of group b; (c) is the fiber image of group c; (d) is the fiber image of group d; (e) is the fiber image of group e; and (f) is the fiber image of group f.

[0066] Figure 8 The images shown are test results for nylon 6-based composite materials with different contents of flowing nanoflowers in Example 3. (a) is an XRD pattern and (b) is an infrared spectrum.

[0067] Figure 9 The surface potential diagrams of nylon 6-based composite materials with different contents of flowing nanoflowers in Example 3 are shown below. (a) is the surface potential diagram of group a; (b) is the surface potential diagram of group b; (c) is the surface potential diagram of group c; (d) is the surface potential diagram of group d; (e) is the surface potential diagram of group e; and (f) is the surface potential diagram of group f.

[0068] Figure 10 The output performance diagrams for the triboelectric device based on LM / PVDF-TrFE and Nylon 6 in Example 4 are as follows: (a) is the open-circuit voltage diagram under different external forces, (b) is the short-circuit current diagram under different external forces, (c) is the peak voltage diagram under 60N, and (d) is the peak current diagram under 60N.

[0069] Figure 11 The output performance diagrams of the triboelectric device based on LM / Nylon 6 and PVDF-TrFE in Example 5 are shown below: (a) is the open circuit voltage diagram under different external forces, (b) is the short circuit current diagram under different external forces, (c) is the peak voltage diagram under 60N and (d) is the peak current diagram under 60N.

[0070] Figure 12The following are the electrical output performance diagrams of the triboelectric device in Example 6 under different pressures: (a) is the open-circuit voltage diagram, (b) is the peak voltage and current diagram, (c) is the short-circuit current diagram, and (d) is the output voltage, current, and power density diagram under different load resistances.

[0071] Figure 13 The output voltage diagram of the triboelectric device in Example 6 after 10,000 cycles is shown.

[0072] Figure 14 The diagram shows the process flow and structure of the interlocking triboelectric device in Example 7.

[0073] Figure 15 This is a schematic diagram illustrating the working principle of the interlocking triboelectric device in Example 7.

[0074] Figure 16 Optical images of (ac)LM / Nylon 6 and (df)LM / PVDF-TrFE with different undulation angles in Example 7; wherein, (a) is an optical image of positive friction material with an undulation angle of 0°; (b) is an optical image of positive friction material with an undulation angle of 30°; (c) is an optical image of positive friction material with an undulation angle of 60°; (d) is an optical image of negative friction material with an undulation angle of 0°; (e) is an optical image of negative friction material with an undulation angle of 30°; and (f) is an optical image of negative friction material with an undulation angle of 60°.

[0075] Figure 17 The figures are tensile stress-strain curves with different undulation angles in Example 7, where (a) is the tensile stress-strain curve of LM / Nylon 6 and (b) is the tensile stress-strain curve of LM / PVDF-TrFE.

[0076] Figure 18 The potential distribution diagrams of triboelectric devices with different undulation angles in COMSOL simulation of Example 7 are shown below: (a), (b), and (c) are potential distribution diagrams of triboelectric devices with an undulation angle of 0°; (d), (e), and (f) are potential distribution diagrams of triboelectric devices with an undulation angle of 30°; and (g), (h), and (i) are potential distribution diagrams of triboelectric devices with an undulation angle of 60°.

[0077] Figure 19 The graphs show the output voltage and output current of the triboelectric devices with three different undulation angles in Example 7 as a function of strain. Specifically, (a) shows the output voltage at a undulation angle of 0°, (b) shows the output current at a undulation angle of 0° as a function of strain, (c) shows the output voltage at a undulation angle of 30°, (d) shows the output current at a undulation angle of 30° as a function of strain, (e) shows the output voltage at a undulation angle of 60°, and (f) shows the output current at a undulation angle of 60° as a function of strain.

[0078] Figure 20 The figures show the voltage and current versus strain curves of the three undulating angle interlocking triboelectric devices in Example 7, where (a) is a curve showing the voltage versus strain and (b) is a curve showing the current versus strain.

[0079] Figure 21 The output voltage diagram of the 30° interlocking triboelectric device of Example 7 after continuous stretching for 10,000 cycles at 2.5Hz is shown. Detailed Implementation

[0080] Example 1: Preparation of fluidized core nanoparticles:

[0081] Weigh 1g of the fluidized gallium-indium alloy into a clean, dry, transparent glass bottle and set aside for later use;

[0082] Take another clean and dry transparent glass bottle and weigh 50 mg of PVP using an electronic analytical balance. Add 15 mL of anhydrous ethanol and 15 mL of deionized water to the bottle in portions using a pipette. Seal the bottle and place it in an ultrasonic cleaner to ensure that the PVP is fully dissolved in the anhydrous ethanol. Transfer the prepared PVP ethanol solution to the previously weighed glass bottle containing gallium indium alloy.

[0083] The sample was initially dispersed in an ultrasonic cleaner for 30 seconds. Then, the sample was transferred to a cell disruptor and ultrasonically treated using a 6mm amplitude transformer. The ultrasonic power was set to 50% (total output power approximately 300W), and the ultrasonic time was 8 hours (ultrasonic on for 2 seconds, then off for 2 seconds). The sample temperature was controlled during ultrasonic treatment using a 20-25°C cold water bath. The solution system and air atmosphere remained constant during the ultrasonic process. After ultrasonic treatment, nano-ink composed of PVP-stabilized flowing nanoparticles (also referred to as flowing nanoflowers, LM, or simply liquid metal) was obtained. The surface morphology of the flowing nanoparticles is shown in the figure below. Figure 1 As shown in (a), its single-grain morphology is as follows Figure 1 As shown in (b), Figure 1 (c) Figure 1 (d) is the EDS image of gallium-indium filament nanoflowers, which shows that Ga and In are present in the filament nanoflowers and that the elements are evenly distributed.

[0084] Example 2: Preparation of Fluidized Particle Negative Fiber Membrane (LM / PVDF-TrFE Composite Nanofiber Membrane)

[0085] Flowing nanoparticles were obtained by centrifugation from the nano-ink of Example 1. These nanoparticles and PVDF-trFE were then dispersed in DMF by centrifugation and ultrasonication to prepare a mixed solution. The concentration of PVDF-trFE in the mixed solution was 13 wt.%. The content of flowing nanoparticles in different experimental groups was as follows: Group a (also known as the PVDF-trFE group): 0 wt.%; Group b (2 wt.% LM group): 2 wt.%; Group c (4 wt.% LM group): 4 wt.%; Group d (6 wt.% LM group): 6 wt.%; Group e (8 wt.% LM group): 8 wt.%; Group f (10 wt.% LM group): 10 wt.%; Note: The content of flowing nanoparticles refers to their percentage content in the spinning solution.

[0086] The solution was stirred at 40℃ until PVDF-TrFE was completely dissolved. The prepared solution was then subjected to electrospinning at 40℃, a roller speed of 1000 r / min, a pump flow rate of 1 ml / h, and a spinning voltage of 15 kV. After drying the sample for 24 h, a negative fiber membrane (LM / PVDF-TrFE composite nanofiber membrane) was obtained.

[0087] 2.1 SEM Measurement:

[0088] Figure 2 SEM results showed that the LM / PVDF-TrFE composite nanofiber membrane was in the form of a loose network, with bright, flowing nanoflowers distributed in the uniformly sized PVDF-TrFE nanofibers.

[0089] like Figure 2 As shown, when the content of the molten nanoflowers increased to 8 wt.% and 10 wt.%, some of the molten nanoflowers agglomerated due to the reduction in the distance between the molten cores (LM).

[0090] 2.2: XRD and IR measurements:

[0091] XRD and IR are shown below. Figure 3 ,in, Figure 3 As shown in Figure (a), diffraction peaks appear at 20.3° and 32.8°, corresponding to the polar β phase of PVDF-TrFE and the flowing nanoflower Ga2O3, respectively. Figure 3 As shown in Figure (b), the diffraction peak intensity of the β phase first increases and then decreases with the increase of the content of the filamentous nanoflowers. Figure 3 As shown in (c) and (d), 765cm -1 The absorption peak at 843 cm⁻¹ corresponds to the nonpolar α phase, while the absorption peak at 843 cm⁻¹ corresponds to the nonpolar α phase. -1 and 1280cm -1The absorption peak appearing at [location] corresponds to the polar β phase. The β phase content increased from 78.6% to 82.1%, and then decreased to 78.4%. The content of the polar β phase reached its peak when the content of the flowing nanoflowers reached 6 wt.%.

[0092] 2.3 Dielectric constant determination

[0093] Figure 4 It can be seen that the dielectric constants of fiber membranes with different contents of filamentous nanoparticles (a), (b), (c), (d), (e), and (f) reached 11.0, 12.6, 13.0, 14.4, 15.0, and 15.6, respectively. The results indicate that the introduction of filamentous nanoflowers successfully improved the dielectric constant of the PVDF-TrFE-based composite nanofiber membrane, with the value increasing from 11 to 15.6 with increasing filamentous nanoflower content.

[0094] 2.4 Polarization

[0095] Figure 5 For Ps and Pr under this field strength, both polarization intensities show a trend of first increasing and then decreasing with the increase of filler content, and both reach their peak value when the filler content is 6wt.%. Figure 5 As shown in (a), as the content of the flowing nanoflowers increased to 6 wt.%, the Ps of the composite nanofiber membrane increased from 8.64 μC·cm⁻¹. -2 Increased to 10.76 μC·cm -2 Pr is 6.74 μC·cm -2 Increased to 8.89 μC·cm -2 .like Figure 5 As shown in (b), the breakdown field strength of the composite nanofiber membrane also shows a trend of first increasing and then decreasing, reaching a peak when the filler content is 6 wt.%, at which point the breakdown field strength increases from 238 kV / mm to 278 kV / mm.

[0096] 2.5 Surface Potential

[0097] Figure 6 The surface potential of composite nanofiber membranes with different contents of flowing nanoflowers is shown. Introducing flowing nanoflowers can cause a negative shift in the surface potential of PVDF-TrFE-based composite nanofiber membranes. This is mainly because the flowing nanoflowers act as traps for triboelectric charges, causing the Fermi level to shift downwards, thus facilitating charge transfer. Furthermore, the triboelectric charges generated at the interface between the conductive filler and the polymer matrix help to generate a local electric field within the composite nanofiber membrane. Figure 6As shown, with the increase of the filamentous nanoflower content to 6 wt.%, the surface potential shifts negatively from -182.5 mV to -858.9 mV. When the filamentous nanoflower content continues to increase to 10 wt.%, the surface potential shifts positively to -366.2 mV. Therefore, after introducing conductive filamentous nanoflowers, the surface potential of the composite nanofiber film can increase by up to 470%, mainly due to the increase in dielectric constant. Furthermore, when the filamentous nanoflower content is 6 wt.%, the PVDF-TrFE-based composite nanofiber film exhibits the highest polar β-phase content, and both saturation polarization and remanent polarization reach their peak values.

[0098] Example 3: Preparation of Fluidized Particle Positive Fiber Membrane (LM / Nylon 6 Nanofiber Membrane)

[0099] Compared with Example 2, the only difference is that nylon 6 was used instead of the PVDF-TrFE. The spinning conditions were: spinning temperature 40℃, roller speed 1000 r / min, pump flow rate 1 ml / h, and spinning voltage 20 kV. After drying the sample for 24 h, LM / nylon 6 nanofiber membranes were obtained. Other operations and parameters were the same as in Example 2. The content of the flow core nanoparticles in different experimental groups were as follows: Group a (also known as Nylon 6 group): 0 wt.%; Group b (2 wt.% LM group): 2 wt.%; Group c (4 wt.% LM group): 4 wt.%; Group d (6 wt.% LM group): 6 wt.%; Group e (8 wt.% LM group): 8 wt.%; Group f (10 wt.% LM group): 10 wt.%; Note: The content of the flow core nanoparticles refers to their percentage content in the spinning solution.

[0100] 3.1: SEM identification:

[0101] SEM microstructure such as Figure 7 As shown in the figure. SEM results indicate that the LM / nylon 6 composite nanofiber membrane exhibits a loose network structure with a high specific surface area, and bright-colored flowing nanoflowers are distributed within the uniformly sized nylon 6 nanofibers. Specifically, as the content of the flowing nanoflowers increases to 8 wt.% and 10 wt.%, some of the flowing nanoflowers agglomerate due to the reduced distance between the fillers.

[0102] 3.2: XRD and IR measurements

[0103] The XRD and IR results are shown in [the table]. Figure 8 ,like Figure 8As shown in Figure (a), a diffraction peak appears at 35.2°, corresponding to the gallium indium flow-core nanoflowers. A diffraction peak for the γ phase of nylon 6 appears at 21.3°, corresponding to the (001) plane, while diffraction peaks for the α and α9 phases of nylon 6 appear at 20.5° and 23.8°, respectively, corresponding to the (020) and (002 / 202) planes. The results indicate that the introduction of flow-core nanoflowers did not introduce impurities, and the intensity of the γ phase in the composite nanofiber membrane showed a trend of first increasing and then decreasing with increasing flow-core nanoflower content, reaching its peak at a flow-core nanoflower content of 6 wt.%.

[0104] like Figure 8 As shown in (b), 1535cm -1 The infrared absorption peak at 1638 cm⁻¹ corresponds to the stretching vibration of the CN group in the amide group of nylon. -1 The infrared absorption peak at 2858 cm⁻¹ corresponds to the infrared absorption of amide I caused by the C=O stretching vibration. -1 and 2932cm -1 The infrared absorption peak at 3300 cm⁻¹ corresponds to the symmetric stretching vibration mode and the asymmetric stretching vibration mode of methylene CH₂. -1 The infrared absorption peak at the specified location corresponds to the stretching vibration of amino group NH. The results show that with the increase of the content of the filamentary nanoflowers, the infrared absorption peak intensities of both amide I and amino group reach their peak values ​​when the filler content is 6 wt.%.

[0105] 3.2: Surface Potential

[0106] Figure 9 The study shows the change in surface potential of the nylon 6-based composite nanofiber membrane after the introduction of filamentous nanoflowers. The introduction of filamentous nanoflowers significantly shifted the surface potential of the composite nanofiber membrane to a positive value, making its electron-donating tendency more pronounced. This is mainly because the introduction of filamentous nanoflowers induces the formation of a weakly polar γ phase and strong hydrogen bonds, maximizing charge accumulation and thus increasing the surface potential of the composite nanofiber membrane. The results show that the trend of surface potential change is consistent with the phase analysis results. As the content of filamentous nanoflowers increases to 6 wt.%, the surface potential increases from 239.8 mV to 1171.1 mV. However, when the content of filamentous nanoflowers continues to increase to 8 wt.% and 10 wt.%, the surface potential shifts negatively to 524.8 mV and 372.7 mV, respectively. Due to the aggregation phenomenon caused by excessive filamentous nanoflowers, the surface potential reaches its peak at a filamentous nanoflower content of 6 wt.%, with an increase of 488%.

[0107] Example 4: Planar triboelectric devices (fluid-core negative electrode and conventional positive electrode triboelectric devices)

[0108] Using conventional nylon positive friction material (the only difference from Example 3 is that the fiber membrane prepared based on its group a is the positive friction material, while the negative fiber membrane of Example 2 is used as the negative friction material), both materials were cut to 2.5 × 2.5 cm. 2 The size is specified. Copper-nickel conductive tape is used as the electrodes for the positive and negative friction layers. Copper wires are connected to the external circuit. The two materials are pasted onto an acrylic plate, and contact separation is achieved by a spring.

[0109] Triboelectric properties are shown in Figure 10 .

[0110] Performance is shown in Table 1:

[0111] Table 1 shows the effect of filamentous nanoflower content on the performance of PVDF-TrFE-based negative friction layer and triboelectric device.

[0112]

[0113] In summary, different forces were applied to LM / PVDF-TrFE-based triboelectric devices with varying filament nanoflower contents to test their triboelectric output performance. The open-circuit voltage and short-circuit current of the triboelectric devices assembled from LM / PVDF-TrFE and Nylon 6 both increased with increasing applied load. With increasing filament nanoflower content, both voltage and current showed a trend of first increasing and then decreasing. Applying a 60N external force at a frequency of 2.5Hz to cause contact separation of the positive and negative friction materials, as the filament nanoflower content increased to 6wt.%, the peak voltage and peak current increased from 294.4V and 59.3μA to 441.7V and 106.7μA, respectively. However, as the filament nanoflower content continued to increase to 10wt.%, the peak voltage and current decreased to 361.2V and 80.6μA, respectively. The voltage and current of this triboelectric device both reached their peak values ​​when the content of the flowing nanoflower was 6 wt.%, which is about 1.5 times and 1.8 times higher than that of triboelectric devices based on pure PVDF-TrFE and nylon 6.

[0114] Example 5: Planar triboelectric device (fluid-core positive electrode and conventional negative electrode triboelectric device)

[0115] Using PVDF-TrFE (the only difference from Example 2 is that the fiber membrane prepared based on its group a is a negative friction material, while the positive fiber membrane of Example 3 is used as a positive friction material), both materials were cut to 2.5 × 2.5 cm. 2 The size is specified. Copper-nickel conductive tape is used as the electrodes for the positive and negative friction layers. Copper wires are connected to the external circuit. The two materials are pasted onto an acrylic plate, and contact separation is achieved by a spring.

[0116] Triboelectric properties are shown in Figure 11 The results are shown in Table 2:

[0117] Table 2: Triboelectric properties of the flow-core positive electrode and conventional negative electrode

[0118]

[0119] Figure 11 Table 2 shows the electrical output performance of triboelectric devices assembled with nylon 6 composite nanofiber membranes and PVDF-TrFE with different contents of flowing nanoflowers. Figure 11 As shown, both the open-circuit voltage and short-circuit current increase with increasing applied load. Therefore, the voltage and current exhibit the same variation trend as the surface potential of the LM / nylon 6 composite nanofiber membrane. Figure 11 As shown, when a 60N external force is applied at a frequency of 2.5Hz, the peak voltage and peak current increase from 294.4V and 59.3μA to 441.7V and 106.7μA respectively as the content of the flowing nanoflowers increases to 6wt.%. However, as the content of the flowing nanoflowers continues to increase to 10wt.%, the peak voltage and current decrease to 350.8V and 75.7μA respectively. The voltage and current of this triboelectric device both reach their peak values ​​at a flowing nanoflower content of 6wt.%, representing an increase of approximately 1.4 times and 1.8 times compared to triboelectric devices constructed based on pure PVDF-TrFE and nylon 6. Therefore, the flowing nanoflowers induce strong hydrogen bonds and the formation of a weakly polar γ phase in the nylon 6-based composite material, achieving a significant positive shift in surface potential and thus optimizing the electrical output performance of the triboelectric device.

[0120] Example 6: Planar triboelectric devices (triboelectric devices with positive and negative flow centers)

[0121] LM / PVDF-TrFE (and group d of Example 2) and the positive fiber membrane of Example 3 (group d of Example 3) were used as negative friction materials, and both materials were cut to 2.5 × 2.5 cm. 2 The size is specified. Copper-nickel conductive tape is used as the electrodes for the positive and negative friction layers. Copper wires are connected to the external circuit. The two materials are pasted onto an acrylic plate, and contact separation is achieved by a spring.

[0122] Triboelectric properties are shown in Figure 12 .

[0123] like Figure 12 As shown, when six different forces are applied to the triboelectric device, both its voltage and current increase with increasing applied pressure. Under a 60N force, the peak voltage and peak current of the triboelectric device are 537.2V and 133.7μA, respectively, which are 1.8 times and 2.2 times higher than those of triboelectric devices constructed from unmodified nylon 6 and PVDF-TrFE. Figure 12As shown in (d), the triboelectric device exhibits 12 W / m under a load resistance of 4 MΩ. 2 With its excellent output power density, it successfully achieved high triboelectric output power density under low frequency and low external force.

[0124] Figure 13 It can be seen that the device exhibits minimal output voltage fluctuation after undergoing 10,000 cycles of fatigue testing at 2.5Hz and 60N. Comparison of voltage signals from two different time periods reveals that the output voltages are not significantly different, and neither the material nor the device shows any damage after the fatigue test. Therefore, the device demonstrates good operational stability and reliability.

[0125] Table 3 shows the performance of different devices.

[0126]

[0127] As shown in Table 3, the positive or negative electrode friction material using the flow-core structure of the present invention can achieve better performance than conventional friction materials. In addition, when both the positive and negative electrodes use friction materials containing the flow-core structure described in the present invention, the synergy between the positive and negative materials can be achieved, resulting in better performance in terms of surface potential difference, peak voltage, peak current, output power, etc.

[0128] Example 7: Triboelectric Device Based on Interlocking Structure

[0129] The positive friction material of Example 3 (Group d of Example 3) and the negative friction fiber membrane of Example 2 (Group d of Example 2) were used as negative friction materials. Both materials were cut to 2.5 × 2.5 cm. 2 The size is specified. Copper-nickel conductive tape is adhered to the back of the material as electrodes, and copper wires are used to connect to the external circuit.

[0130] By removing the acrylic support layer from the rigid device successfully modified based on molten nanoflowers and replacing the spring structure with sponge foam (EVA) to achieve the rebound effect, a flexible triboelectric device with an interlocking structure can be constructed. Figure 14 This diagram illustrates the relevant process flow and structure of an interlocking triboelectric device. The working mode of this flexible device differs from the traditional vertical contact-separation mode. It achieves contact separation of positive and negative friction materials through periodic stretching and compression. Since the friction area and tensile properties of the untreated friction material are limited during compression, to enhance the contact area and tensile properties of the two materials, the friction material undergoes surface patterning pretreatment using molds with different undulation angles (0°, 30°, and 60°) to obtain wavy positive and negative friction materials. Finally, these are assembled into flexible triboelectric devices with interlocking structures of three different wavy undulation angles.

[0131] Figure 15The working principle of this interlocking triboelectric device differs from the traditional vertical contact-separation model. It achieves contact and separation of positive and negative friction materials through horizontal stretching and compression. Initially, both material surfaces are electrically neutral. When the positive and negative friction materials come into contact under compression, triboelectric charging generates positive and negative charges on the LM / Nylon 6 and LM / PVDF-TrFE composite nanofiber membranes, respectively. Subsequently, under tension, the friction layers separate, creating a potential difference that drives electron flow in the external circuit, generating a transient current until electrical equilibrium is reached. When the friction layers come into contact again under compression, electrostatically induced charges flow back to compensate for the potential difference between the upper and lower electrodes, generating opposite currents. Therefore, under periodic compression and stretching, the triboelectric device generates an alternating electrical signal.

[0132] Figure 16 Optical images of LM / Nylon 6 and LM / PVDF-TrFE with different undulation angles are presented, comparing the surface morphology of positive and negative friction materials after surface patterning with molds at angles of 0°, 30°, and 60°. The results show that the surface of the friction materials exhibits some wear after molding. The positive and negative friction materials with an undulation angle of 60° show some wear, and in some areas, conductive adhesive tape on the back of the material is even visible. This can lead to poor fit of subsequently assembled devices, potentially affecting the electrical output performance of the devices. Figure 17 (a) shows the tensile stress-strain curve of the LM / Nylon 6 composite nanofiber membrane. The tensile strength of the composite material increases with the increase of the surface undulation angle, and finally the elongation at break reaches 64.4% when the undulation angle is 60°. Figure 17 As shown in (b), the elongation at break of the LM / PVDF-TrFE composite nanofiber membrane also reaches a maximum of 93.8% at an undulation angle of 60°.

[0133] To further analyze the influence of wave undulation angle on the performance of triboelectric devices, a finite element simulation was performed on the triboelectric device with this interlocking structure. For example... Figure 18 As shown, two locations with a spacing of 0.1 mm and 2.6 mm between the positive and negative friction layers were selected during the dynamic contact separation process. Figure 18 As shown in (b), when the surface of the friction material is smooth, the theoretical maximum potential difference is approximately 311V. Figure 18As shown in (d), (e), (f), (g), (h), and (i), when the material surface is pre-treated to have a wavy pattern, the theoretical potential increases due to the increased effective contact area. Comparing the two angles, the theoretical maximum potential difference of the triboelectric device with a 30° undulation angle is approximately 849V, while that with a 60° undulation angle is approximately 661V. Furthermore, according to the local simulation results of the triboelectric material with different undulation angles, the peak potential is mainly concentrated at the location of the flowing nanoflowers, with the potential difference of the triboelectric device with a 30° undulation angle reaching a maximum of 465V. As the density of the material surface pattern increases, the theoretical potential difference decreases slightly. Due to the high aspect ratio of the micropattern, the triboelectric material with a 60° undulation angle has a large height difference in the vertical direction, which is not conducive to sufficient contact and friction, thus relatively weakening the electrostatic induction effect and triboelectric effect.

[0134] in accordance with Figure 17 The elongation at break is used to characterize the electrical output performance of triboelectric devices, such as... Figure 19 As shown, stretching the device at a frequency of 2.5 Hz and with different forces causes varying degrees of strain in the wavy friction layer, and both the output voltage and current increase with the degree of deformation. The device with the untreated friction layer achieves peak voltage and current of 70.4 V and 11.2 μA at 40% strain; the device with a 30° undulation angle achieves peak voltage and current of 188.6 V and 31.1 μA at 60% strain; and the device with a 60° undulation angle achieves peak voltage and current of 126.9 V and 20.3 μA at 60% strain. This is mainly because the effective contact area of ​​the wavy positive and negative friction layers is increased, and the interlocking structure helps to enhance the extrusion deformation of the flexible conductive flow-core nanoflowers and promote secondary polarization. Therefore, triboelectric devices with interlocking structures built based on wavy friction materials are more likely to achieve excellent triboelectric output performance.

[0135] like Figure 20 As shown in (a) and (b), the current sensitivity and voltage sensitivity of the untreated triboelectric device are 0.23 μA and 1.14 V, respectively. The current sensitivity and voltage sensitivity of the device with a 30° undulation angle are 0.51 μA and 3.38 V, respectively, and the current sensitivity and voltage sensitivity of the device with a 60° undulation angle are 0.36 μA and 2.11 V, respectively. Therefore, the triboelectric device with an interlocking structure after the friction layer is pressed using a 30° mold exhibits the best electrical output performance, with peak voltage and current reaching 188.6 V and 31.1 μA, respectively, and its sensitivity is relatively higher. While the friction layer with a 60° undulation angle has denser waves and a larger effective contact area, its surface wear is severe, and due to the sharper peak shape of the contact surface, the interlocking fit during device operation is poor, thus reducing its output performance.

[0136] like Figure 21 As shown, the triboelectric device with an interlocking structure based on a friction layer with an undulation angle of 30° exhibits relatively excellent output voltage stability after 10,000 cyclic stretching cycles at a frequency of 2.5 Hz. Comparing the voltage signals at two different time periods, the results show that the voltage remains essentially consistent. Furthermore, both composite nanofiber membranes and the triboelectric device showed no significant wear after fatigue testing. Therefore, this flexible triboelectric device with an interlocking structure possesses excellent output performance stability and operational durability.

[0137] Comparative Example 1

[0138] Compared with Example 1, the only difference is that the solvent in step 1 is water, while the other operations and parameters are the same as in Example 1.

[0139] Comparative Example 2

[0140] Compared with Example 1, the only difference is that the solvent in step 1 is only ethanol, while the other operations and parameters are the same as in Example 1.

[0141] Comparative Example 3

[0142] Compared to Example 1, the only difference is that the atmosphere in step 1 is nitrogen.

[0143] Comparative Example 4

[0144] Compared with Example 1, the only difference is that the processing time in step 1 is 1 hour.

[0145] Comparative Example 5

[0146] Compared with Example 1, the only difference is that the fluidized alloy does not undergo step 1, but directly replaces the fluidized particles in an equal amount for step 2 and subsequent processing.

[0147] Comparative Example 6

[0148] Compared with Example 6, the only difference is that the positive electrode does not contain fluidized particles, and the negative electrode does not contain the fluidized particles mentioned above.

[0149] Triboelectric particles were prepared by replacing the flow core particles with particles prepared in Comparative Examples 1-6 as inorganic additives, and tested according to the method of Example 6. The experimental results are shown in Table 4.

[0150] Table 4: Properties of fiber membranes prepared in each comparative example and the triboelectric properties of the assembled membranes.

[0151]

[0152] In summary, this invention innovatively disperses nanoflowers with special morphologies in polymer fibers, making them suitable for the application requirements of triboelectric devices and improving their triboelectric performance.

[0153] This invention combines the negative and positive electrodes, which further enhances the synergy between the electrodes and helps to improve the performance of the triboelectric device. Furthermore, by setting the positive and negative electrodes in an interlocking structure and controlling their undulation angle, the performance of the triboelectric device can be further improved through synergy.

Claims

1. A fluidized nanoflower / polymer composite fiber membrane, characterized in that, It is a fiber membrane material made by interlacing and weaving functional nanofibers; The functional nanofibers include polymer fibers and fluidized nanoflowers dispersed therein; The polymer in the polymer fiber is a positive polymer or a negative polymer; The flowing nanoflowers are flower-shaped nanoparticles, comprising a gallium indium composite oxide shell with a wrinkled surface and a flowing gallium indium alloy core filled within the shell. The preparation steps of the molten nanoflower / polymer composite fiber membrane include: Step 1: A fluidized gallium-indium alloy was placed in an alcohol-containing aqueous solution and then subjected to cavitation treatment in an oxygen-containing atmosphere to form a gallium-indium composite oxide shell on the surface of the fluidized gallium-indium alloy, thereby obtaining the fluidized nanoflower. The cavitation process involves a power of 100W to 500W and a duration of 7 to 9 hours. Step 2: The molten nanoflowers and polymers were slurried with a solvent to obtain a spinning solution, which was then subjected to electrospinning to obtain the molten nanoflower / polymer composite fiber membrane.

2. The fluidized nanoflower / polymer composite fiber membrane as described in claim 1, characterized in that, Positive polymers include at least one of nylon 6, nylon 11, nylon 66, and polyacrylonitrile; The negative polymers include PVDF-based polymers; The diameter of fibers from negative polymers is 100~500nm; the diameter of fibers from positive polymers is 200~600nm. The particle size of the flowing nanoflower is 0.5~5μm; the thickness of the shell is 0.7~3nm; In the Flowing Nanoflower / Polymer Composite Fiber Membrane, the content of Flowing Nanoflower is 10~45wt.%; the porosity is 50~90vol.%; and the thickness is 1~500μm.

3. A method for preparing the fluidized nanoflower / polymer composite fiber membrane according to claim 1 or 2, characterized in that the step... include: Step 1: A fluidized gallium-indium alloy was placed in an alcohol-containing aqueous solution and then subjected to cavitation treatment in an oxygen-containing atmosphere to form a gallium-indium composite oxide shell on the surface of the fluidized gallium-indium alloy, thereby obtaining the fluidized nanoflower. The cavitation process involves a power of 100W to 500W and a duration of 7 to 9 hours. Step 2: The molten nanoflowers and polymers were slurried with a solvent to obtain a spinning solution, which was then subjected to electrospinning to obtain the molten nanoflower / polymer composite fiber membrane.

4. The method for preparing the flowing nanoflower / polymer composite fiber membrane as described in claim 3, characterized in that, The alcohol in the alcohol-containing aqueous solution includes at least one of methanol and ethanol; The volume content of alcohol in the alcohol-containing aqueous solution is 10~80 vol.%; The liquid-to-solid ratio of alcohol-containing aqueous solutions and gallium-indium alloys is 10~50 mL / g; The oxygen content in the oxygen-containing atmosphere is 10-30%.

5. The method for preparing the flowing nanoflower / polymer composite fiber membrane as described in claim 3, characterized in that, The alcohol-containing aqueous solution also contains a stabilizer, including PVP; The concentration of the stabilizer in the alcohol-containing aqueous solution is 1~3 mg / mL.

6. The method for preparing the flowing nanoflower / polymer composite fiber membrane as described in claim 3, characterized in that, The solvent in the spinning solution is an organic solvent capable of dissolving the polymer; The polymer concentration is 5-20 wt.%, and the concentration of the flowing nanoflowers is 2-10 wt.%. The voltage for electrostatic methods is 15~20kV; the spacing is 10~15cm.

7. A triboelectric electrode, comprising a fiber membrane and a conductive metal composite thereon on its surface; characterized in that, The fiber membrane is the fluidized nanoflower / polymer composite fiber membrane according to claim 1 or 2, or the fluidized nanoflower / polymer composite fiber membrane prepared by any one of the preparation methods of claims 3 to 6; In the case of a flowing nanoflower / polymer composite fiber membrane, the polymer is a positive polymer, and the corresponding triboelectric electrode is a positive electrode; or, the polymer in the flowing nanoflower / polymer composite fiber membrane is a negative polymer, and the corresponding triboelectric electrode is a negative electrode.

8. A triboelectric device, comprising a positive electrode and a negative electrode, wherein, The polymer surfaces of the positive and negative electrodes are arranged opposite each other, and a barrier layer or cavity is provided between the positive and negative electrodes. The positive electrode is the positive electrode in the triboelectric electrode of claim 7, and / or the negative electrode is the negative electrode in the triboelectric electrode of claim 7.

9. The triboelectric device as described in claim 8, characterized in that, The positive electrode is the positive electrode in the triboelectric electrode of claim 7, and the negative electrode is the negative electrode in the triboelectric electrode of claim 7. There is a cavity between the positive electrode and the negative electrode, and the two have an interlocking structure; The undulation angle of the interlocking structure is below 60°.

10. An application of the triboelectric device according to any one of claims 8 to 9, characterized in that, It can be used to prepare motion energy harvesting and / or gesture recognition sensors.

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