Preparation method and application of friction nano generator with high surface charge density

Abstract

The invention relates to the technical field of nano materials, and provides a preparation method and application of a friction nano generator with high surface charge density. The invention aims to overcome the defects of low surface charge density, environmental influence, easy aging and the like in high-frequency mechanical energy collection of the existing friction nano-generator, and the application of the friction nano-generator in environmental mechanical energy collection is improved. The main scheme is as follows: 4, the preparation method comprises the following steps: dissolving 4, 4 '-diaminodiphenyl ether in N, N'-dimethylacetamide, adding diphenyl ether dianhydride into the solution to synthesize a polyamide acid solution, carrying out electrospinning and high-temperature treatment on the solution to obtain an imidized nanofiber membrane, treating the surface of the nanofiber membrane through a plasma sputtering instrument, selecting a fluorinated ethylene-propylene copolymer as an electric negative electrode material, and carrying out electrospinning and high-temperature treatment on the surface of the nanofiber membrane. And pasting an electrode and packaging to construct the friction nano generator. The invention is used in the fields of friction power generation, mechanical sensing and the like, and has the advantages of simple process, high preparation speed, high yield, low cost, good robustness, no environmental influence and high output performance.

Description

Technical Field

[0001] The present invention belongs to the technical field of nanomaterials, and in particular relates to a preparation method and application of a high surface charge density tribo-nanogenerator. Background Art

[0002] Since the Industrial Revolution, energy has played a dominant role in social development and economic construction. However, due to rapid industrialization and population growth, energy dependence and demand have also increased. Current energy utilization models are gradually failing to meet the demands of rapid economic and social development, and the energy crisis has become a top priority for development in every country. Exploring alternative, renewable, and clean energy sources has become an urgent need for all countries. Solar, wind, and geothermal energy, as clean energy sources, are difficult to utilize rationally and effectively due to geographical, weather, and environmental constraints, as well as high costs. Triboelectric nanogenerators (TGNs), with their efficient energy conversion capabilities and excellent environmental adaptability, offer significant advantages and broad application prospects in the new energy sector. However, while TGNs excel at harvesting low-frequency mechanical energy, they are susceptible to electric field breakdown when harvesting high-frequency mechanical energy. Furthermore, TGN materials are susceptible to aging and wear over long periods of operation. Furthermore, in high-humidity environments, the charge generated by TGNs is easily lost, significantly reducing energy harvesting efficiency. Therefore, constructing TGNs with high surface charge density, humidity resistance, and high stability is of great practical significance.

[0003] Through the above analysis, the problems and defects of the existing technology are: the existing friction nanogenerators have disadvantages such as surface charge density, susceptibility to environmental influences and easy aging in high-frequency mechanical energy collection, which limit the collection and application of mechanical energy by friction nanogenerators. Summary of the Invention

[0004] The technical problem addressed by this invention is to overcome the shortcomings of existing triboelectric nanogenerators (TGNs) for high-frequency mechanical energy harvesting, such as low surface charge density, susceptibility to charge loss due to humidity, and material aging and wear. By synergistically optimizing material modification, surface treatment, and environmental packaging, the TGNs' charge density, environmental adaptability, and long-term stability are enhanced.

[0005] The present invention is achieved by a method for improving the performance of a high surface charge density triboelectric nanogenerator, comprising the following steps:

[0006] Step 1: dissolving a certain amount of 4,4'-diaminodiphenyl ether in N,N'-dimethylacetamide, adding a certain molar ratio of diphenyl ether dianhydride in four portions, and stirring for 6 hours under an argon atmosphere to obtain a transparent and viscous polyamic acid solution;

[0007] Step 2: electrospinning the polyamic acid solution by electrospinning technology to obtain a white nanofiber film; then imidizing the nanofiber film in a muffle furnace to obtain a polyimide fiber film;

[0008] In step 3, the fiber film and the fluorinated ethylene propylene copolymer film serving as the negative electrode are plasma treated by a plasma sputtering apparatus, and then nickel cloth tape is affixed to the surface of the film as an electrode. The two friction films are encapsulated into a friction nanogenerator using Ecoflex.

[0009] Furthermore, the molar ratio of diphenyl ether dianhydride to 4,4'-diaminodiphenyl ether in step 1 is 1.02:1.

[0010] Furthermore, the reaction in step 2 is carried out at 0°C.

[0011] Furthermore, in step 3, the high-voltage power supply voltage is 16 kV, the electrospinning flow rate is 0.3 mL / h, the distance of the needle collecting device is 16 cm, the ambient humidity during the electrospinning process needs to be controlled below 50%; and the imidization temperature is 260°C.

[0012] Furthermore, in step 2, the organic solvent in the nanofiber film needs to be removed in a vacuum drying oven before imidization.

[0013] Furthermore, in step 3, dry air is injected into the two friction layers, and the air humidity should be less than 30%.

[0014] The present invention also provides a triboelectric nanogenerator with high surface charge density, which is prepared by the above method.

[0015] The present invention also provides a triboelectric power generation device, which is prepared using the above-mentioned high surface charge density triboelectric nanogenerator.

[0016] The present invention also provides a pressure sensor, which is prepared using the above-mentioned high surface charge density friction nanogenerator.

[0017] The high surface charge density triboelectric nanogenerator and its preparation method provided by the present invention achieve significant improvements in triboelectric output performance, stability, and environmental adaptability through the synergistic effects of material selection, process optimization, and surface modification. These advantages are specifically reflected in the following technical advantages:

[0018] 1. High surface charge density and improved output performance

[0019] The fiber surface with a wrinkled structure is formed by electrospinning of polyimide nanofiber film and plasma surface treatment. Figure 3), significantly increased the effective friction contact area, and the surface charge density increased by more than 3 times compared with the untreated sample (compared Figure 5 and Figure 6 ).

[0020] The optimized material system (polyimide and fluorinated ethylene propylene copolymer) combined with the high electronegativity difference, the output voltage gradually reaches the maximum under the pressure of 1-2N ( Figure 11 ), the output power reaches its peak value when the load is 10MΩ ( Figure 7 ), which is significantly better than traditional friction nanogenerators.

[0021] 2. Good device stability

[0022] By using polyimide nanofiber film as the nano-friction layer, since polyimide has good mechanical properties and high-temperature resistance, it can withstand high temperatures of up to 400°C. These allow the nano-friction generator to be used continuously for a long time without being affected by temperature.

[0023] 3. Good anti-interference performance

[0024] Nanogenerators in the prior art are all used directly in the atmospheric environment. Since the humidity in the atmosphere varies with the seasons, a high humidity environment will lead to a rapid loss of charge generated by friction, resulting in a decrease in output power. This application innovatively encapsulates the friction nanogenerator in Ecoflex, so that the friction nanogenerator can be isolated from the ambient air. Thanks to the strong interaction between the Ecoflex molecular chains, Ecoflex will not penetrate into the film, thus ensuring the independence of the friction layer. Injecting dry air between the two friction layers ensures that the working environment of the nano-friction generator is always a low-humidity environment, thereby achieving stable high output and greatly improving the application range and output efficiency of the friction nanogenerator.

[0025] 4. Existing triboelectric nanogenerators use PDMS and PETITO for their friction layers, respectively. However, PDMS has a weaker electronegativity than the polyimide we selected. Furthermore, PDMS is a simple membrane, while the polyimide friction layer selected in this application is a nanofiber film synthesized via electrospinning. This nanofiber film effectively increases the contact area during friction, and surface plasma treatment further increases the contact area of the nanofibers, significantly enhancing the electrical output. Furthermore, the electron loss capacity of PET-based ITO is much weaker than that of the fluorinated ethylene propylene copolymer selected in this application, which will reduce the overall output of the triboelectric nanogenerator.

[0026] 5. The technical solution to be protected by the present invention has low cost, simple process, rapid preparation, large single preparation quantity, and is easy to scale up industrially; the materials used in the solution of the present invention are abundant in source and easy to obtain; and the high surface charge density friction nanogenerator prepared has good stability and electrical output performance, and is easy to be further processed into an energy collection device in the later stage.

[0027] 6. The technical solution to be protected by the present invention has the technical characteristics of rapid preparation, large output and low cost; the high surface charge density friction nanogenerator prepared by the present invention has good mechanical and electrical properties.

[0028] 7. The expected benefits and commercial value of the technical solution of the present invention after transformation are as follows: The present invention can realize the rapid preparation of friction nanogenerators with high output performance and high stability, and the obtained friction nanogenerators have simple processes, large synthesis yields, and are easy to scale up industrially, and have high commercial and practical value. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a flow chart of a method for preparing a nano-triboelectric film with high surface charge density provided by an embodiment of the present invention;

[0030] Figure 2 This is a structural diagram of the nano-friction generator obtained in Example 1 of the present invention;

[0031] Figure 3 is a scanning electron microscope image of the product obtained in Example 1 of the present invention;

[0032] Figure 4 This is a working principle diagram of the triboelectric nanogenerator obtained in Example 1 of the present invention;

[0033] Figure 5 is the output voltage of the nanofiber film without plasma treatment;

[0034] Figure 6 is the output voltage of the triboelectric nanogenerator obtained in Example 1 of the present invention;

[0035] Figure 7 is the relationship between the output performance and load of the triboelectric nanogenerator obtained in Example 1 of the present invention;

[0036] Figure 8 is the output voltage of the triboelectric nanogenerator obtained in Example 1 of the present invention under a pressure of 0.5N;

[0037] Figure 9 is the output voltage of the triboelectric nanogenerator obtained in Example 1 of the present invention under a pressure of 1N;

[0038] Figure 10is the output voltage of the triboelectric nanogenerator obtained in Example 1 of the present invention under a pressure of 1.5N;

[0039] Figure 11 is the output voltage of the triboelectric nanogenerator obtained in Example 1 of the present invention under a pressure of 2N;

[0040] Figure 12 is a graph showing the mechanical properties of the polyimide nanofiber film obtained in Example 1 of the present invention;

[0041] Figure 13 This is a structural diagram of Example 2;

[0042] Figure 14 This is a structural diagram of Example 3;

[0043] 1-Ecoflex, 2-Nickel cloth, 3-Polyimide, 4-Fluorinated ethylene propylene copolymer, 5-Inner wall of outer cylinder, -Inner cylinder. DETAILED DESCRIPTION

[0044] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0045] In order to enable those skilled in the art to fully understand how to implement the present invention, this section provides an explanatory embodiment that expands on the technical solutions of the claims.

[0046] like Figure 1 As shown, a method for preparing a high surface charge density triboelectric nanogenerator provided by an embodiment of the present invention includes:

[0047] S101, dissolving a certain amount of 4,4'-diaminodiphenyl ether in N,N'-dimethylacetamide, then adding a certain molar ratio of diphenyl ether dianhydride in four portions, and stirring under an argon atmosphere for 6 hours to obtain a transparent and viscous polyamic acid solution.

[0048] S102, electrospinning the polyamic acid solution by electrospinning technology to obtain a white nanofiber film; then imidizing the nanofiber film in a muffle furnace to obtain a polyimide fiber film.

[0049] S103, plasma treatment is performed on the fiber film and the fluorinated ethylene propylene copolymer film serving as the negative electrode using a plasma sputtering apparatus, and then nickel cloth tape is attached to the surface of the film as an electrode. The two friction films are encapsulated into a friction nanogenerator using Ecoflex.

[0050] In the embodiment of the present invention, the molar ratio of diphenyl ether dianhydride to 4,4'-diaminodiphenyl ether in step S101 is 1.02:1.

[0051] The reaction in step S101 in the embodiment of the present invention is carried out at 0°C.

[0052] In step S102 of the embodiment of the present invention, the high voltage power supply voltage is 16 kV, the electrospinning flow rate is 0.3 mL / h, the needle collecting device distance is 16 cm, the ambient humidity during the electrospinning process needs to be controlled below 50%; and the imidization temperature is 260°C.

[0053] In step S102 of the embodiment of the present invention, the organic solvent in the nanofiber film needs to be removed in a vacuum drying oven before imidization.

[0054] In step S103 of the embodiment of the present invention, dry air is injected into the two friction layers, and the air humidity should be less than 30%.

[0055] Example 1

[0056] (1) First, 0.5108 g of 4,4'-diaminodiphenyl ether was dissolved in 7 ml of N,N'-dimethylacetamide, and then 0.7659 g of diphenyl ether dianhydride was added in four portions. The mixture was stirred under an argon atmosphere for 6 h until a transparent and viscous polyamic acid solution was obtained. It is worth noting that diphenyl ether dianhydride needs to be added in four portions and cannot be added all at once. Otherwise, a slight change in the content will lead to synthesis failure. Only about 90% can be added for the first time, and then slowly added until the appropriate viscosity is reached.

[0057] (2) The polyamide acid solution is electrospun by electrospinning technology to obtain a white nanofiber film; then the residual organic solvent in the film is removed in a vacuum oven, and then the nanofiber film is imidized in a muffle furnace to obtain a polyimide fiber film.

[0058] (3) The fiber film and the fluorinated ethylene propylene copolymer film as the negative electrode were plasma treated by a plasma sputtering apparatus. Then, nickel cloth tape was attached to the surface of the film as an electrode. The two friction films were encapsulated into a friction nanogenerator using Ecoflex. Dry air was injected between the two friction layers, and the air humidity should be less than 30%.

[0059] In order to prove the creativity and technical value of the technical solution of the present invention, this section provides application examples of the claimed technical solution on specific products or related technologies.

[0060] The present invention provides a method for preparing a triboelectric nanogenerator with high triboelectric output performance and high stability. The resulting triboelectric nanogenerator can be applied to fields such as mechanical energy recovery and mechanical sensing. This method offers advantages such as simple process, rapid preparation, high yield, low cost, good robustness, and high output performance. It enables the rapid preparation of a triboelectric nanogenerator with high triboelectric output performance and high stability, and has high commercial and practical value. The present invention has achieved positive results during development and use, demonstrating significant advantages over existing technologies. The following describes this method with reference to experimental data, charts, and other data.

[0061] The high surface charge density triboelectric nanogenerator prepared in Example 1 is applied to the field of mechanical energy collection and mechanical sensing. Its structure diagram and scanning electron microscope image of the polyimide film friction layer are shown in FIG. Figure 2 、

[0062] Figure 3 As shown, Ecoflex encapsulates the friction layer, isolating it from the effects of humidity. A dry air environment significantly boosts the output power of the triboelectric nanogenerator. Polyimide nanofibers have a uniform diameter, but after plasma surface treatment, they develop a wrinkled structure. These wrinkles significantly increase the contact area of the friction layer during the operation of the triboelectric nanogenerator, thereby increasing its surface charge density.

[0063] Figure 4 The figure shows the working principle of the friction nanogenerator. During the triboelectric generation process, as the polyimide film moves downward, the upper and lower friction layers are in complete contact. Due to the large difference in electronegativity between the two friction materials, positive and negative charges are generated on the surfaces of the polyimide film and the fluorinated ethylene propylene copolymer film, respectively. When the polyimide film moves upward, the charge transfer between the top and bottom electrodes causes current to flow through the external load. When the polyimide film moves downward again, the transferred charge flows in the opposite direction, and electrical energy is generated cyclically through this output mechanism. The triboelectric outputs generated by the polyimide film without plasma surface treatment and the polyimide film after surface plasma surface treatment are shown as follows: Figure 5 and Figure 6 As shown in the figure, it can be found that under the same pressure conditions, the polyimide film that has been surface treated with plasma can produce much higher output than the polyimide film that has not been surface treated with plasma, which shows that the output performance of the friction nanogenerator can be significantly improved by increasing the surface charge density of the film.

[0064] Figure 7 The figure shows the change of the electrical output of the friction nanogenerator with the load resistance. The output power first increases and then decreases with the load, reaching the highest point near 10MΩ.

[0065] Figure 8-11Figure 3 shows how the output voltage of the friction nanogenerator changes with pressure. It can be found that the greater the pressure, the higher the output voltage of the friction nanogenerator.

[0066] Figure 12 This is the mechanical properties diagram of the polyimide nanofiber film in the friction nanogenerator. It can be seen that the fracture strength of the polyimide nanofiber film is as high as 17MPa, which proves that the friction nanogenerator has high mechanical properties.

[0067] The preferred embodiments of the present invention have been described in detail above. It should be understood that numerous modifications and variations based on the concepts of the present invention can be made by one of ordinary skill in the art without inventive effort. Therefore, any technical solution that can be derived by one of ordinary skill in the art through logical analysis, reasoning, or limited experimentation based on the concepts of the present invention and the prior art should be within the scope of protection defined by the claims.

[0068] Example 2

[0069] The polyimide nanofiber film is fixed to the inner wall of the hollow cylinder and arranged in sequence at unit intervals; the fluorinated ethylene propylene copolymer is fixed to the outer wall of the solid cylinder and also arranged in sequence at unit intervals. The inner diameter of the hollow cylinder is slightly larger than the outer diameter of the solid cylinder to ensure that the two films can just touch each other. The cross-sectional diagram is shown in FIG. Figure 13 As shown in the figure, by rotating the solid cylinder in the middle, the two films undergo a periodic contact-separation motion, which generates charge movement and thus generates current in the circuit.

[0070] Example 3

[0071] The polyimide nanofiber film and fluorinated ethylene propylene copolymer are arranged in a face-to-face manner, with the ends of the upper and lower friction layers in contact and the middle part concave, forming a hollow structure. Figure 14 During the pressing process, the upper and lower surfaces contact and separate, resulting in a transfer of charge, which in turn creates a voltage difference in the circuit, achieving the purpose of generating energy.

Claims

1. A method for preparing a triboelectric nanogenerator with high surface charge density, characterized in that: The following steps are involved: Step 1: dissolving 4,4'-diaminodiphenyl ether in N,N'-dimethylacetamide, adding diphenyl ether dianhydride in four portions, and stirring under an argon atmosphere until a transparent and viscous polyamic acid solution is obtained; Step 2: electrospinning the polyamic acid solution by electrospinning technology to obtain a white nanofiber film; then imidizing the nanofiber film in a muffle furnace to obtain a polyimide fiber film; In step 3, the polyimide fiber film and the fluorinated ethylene propylene copolymer film serving as the negative electrode are plasma treated by a plasma sputtering apparatus, and then nickel cloth tape is affixed to the surface of the film as an electrode. The two friction films are encapsulated into a friction nanogenerator using Ecoflex.

2. The method for preparing a high surface charge density triboelectric nanogenerator according to claim 1, wherein: The molar ratio of diphenyl ether dianhydride to 4,4'-diaminodiphenyl ether in step 1 is 1.02:

1.

3. The method for preparing a high surface charge density triboelectric nanogenerator according to claim 1, wherein: The reaction in step 1 was carried out at 0°C.

4. The method for preparing a high surface charge density triboelectric nanogenerator according to claim 1, wherein: The high-voltage power supply voltage in step 2 is 16 kV, the electrospinning flow rate is 0.3 mL / h, the distance of the needle collecting device is 16 cm, and the ambient humidity during the electrospinning process needs to be controlled below 50%; the imidization temperature is 260°C.

5. The method for preparing a triboelectric nanogenerator with high surface charge density according to claim 1, wherein: In step 2, the organic solvent in the nanofiber film needs to be removed in a vacuum drying oven before imidization.

6. The method for preparing a high surface charge density triboelectric nanogenerator according to claim 1, wherein: In step 3, dry air is injected into the two friction layers, and the air humidity should be less than 30%.

7. A high surface charge density triboelectric nanogenerator, characterized in that: The triboelectric nanogenerator is prepared by using the preparation method of the triboelectric nanogenerator with high surface charge density according to any one of claims 1 to 5.

8. A triboelectric power generation device, characterized in that: The triboelectric power generation device is prepared using the high surface charge density triboelectric nanogenerator described in claim 7.

9. A pressure sensor, wherein the pressure sensor is prepared using the high surface charge density triboelectric nanogenerator according to claim 7.

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