A friction nanogenerator and a preparation method and application thereof

Abstract

The application discloses a friction nanogenerator and a preparation method and application thereof. The composition of the friction nanogenerator comprises a first friction unit, a second friction unit and a flexible support framework, the composition of the first friction unit comprises a first electrode layer and a first friction layer which are laminated and attached, the composition of the second friction unit comprises a second electrode layer and a second friction layer which are laminated and attached, the first electrode layer and the second electrode layer are both fixed on the flexible support framework, the first friction layer and the second friction layer are arranged face to face and do not directly contact each other, the first friction layer is a porous cellulose acetate film, and the second friction layer is a polyvinylidene fluoride film. The friction nanogenerator has the advantages of light mass, good flexibility, high stability and the like, and the preparation method is simple, the production cost is low, the equipment requirement is low, and the friction nanogenerator is suitable for large-scale production and application.

Description

Technical Field

[0001] This invention relates to the field of triboelectric nanogenerator technology, specifically to a triboelectric nanogenerator, its preparation method, and its application. Background Technology

[0002] Triboelectric nanogenerators are a novel type of power generation device based on triboelectricity and electrostatic induction effects. They can convert low-frequency mechanical energy in the environment into electrical energy, making them a promising energy harvesting method with broad application prospects. However, existing triboelectric nanogenerators generally suffer from the following problems: 1) The friction materials have poor wear resistance and flexibility, resulting in a short service life, which greatly limits their practical applications (e.g., they cannot be used in wearable devices); 2) The fabrication methods (e.g., hydrothermal growth, chemical vapor deposition, electrospinning, etc.) are characterized by long cycles, high costs, and complex operations, making large-scale industrial production difficult. In summary, existing triboelectric nanogenerators still have significant shortcomings and cannot fully meet the requirements of practical applications.

[0003] Therefore, it is of great significance to develop a triboelectric nanogenerator with good flexibility, high stability, simple preparation process and low manufacturing cost. Summary of the Invention

[0004] The purpose of this invention is to provide a triboelectric nanogenerator, its preparation method, and its application.

[0005] The technical solution adopted in this invention is:

[0006] A triboelectric nanogenerator comprises a first friction unit, a second friction unit, and a flexible support frame. The first friction unit comprises a first electrode layer and a first friction layer laminated together. The second friction unit comprises a second electrode layer and a second friction layer laminated together. Both the first electrode layer and the second electrode layer are fixed on the flexible support frame. The first friction layer and the second friction layer are arranged facing each other, but they do not directly contact each other. The first friction layer is a porous cellulose acetate membrane. The second friction layer is a polyvinylidene fluoride (PVDF) membrane.

[0007] Preferably, the distance between the first friction layer and the second friction layer is 1cm to 2cm.

[0008] Preferably, the thickness of the first friction layer is 40 μm to 50 μm.

[0009] Preferably, the thickness of the second friction layer is 50 μm to 60 μm.

[0010] Preferably, both the first electrode layer and the second electrode layer are copper foil.

[0011] Preferably, the flexible support frame is a polyethylene terephthalate (PET) film.

[0012] Preferably, one side of the porous cellulose acetate membrane has micropores with a pore size of 1μm to 5μm, and the other side has micropores with a pore size of 15nm to 30nm.

[0013] A method for preparing the triboelectric nanogenerator as described above includes the following steps:

[0014] 1) A cellulose acetate solution is coated onto a substrate to form a film, and then soaked in water to obtain a porous cellulose acetate membrane; a polyvinylidene fluoride solution is coated onto a substrate to form a film to obtain a polyvinylidene fluoride membrane.

[0015] 2) The first electrode layer is adhered to the surface of the porous cellulose acetate membrane, and the second electrode layer is adhered to the surface of the polyvinylidene fluoride membrane. The porous cellulose acetate membrane and the polyvinylidene fluoride membrane are then placed face to face and kept from contact. The first electrode layer and the second electrode layer are then fixed on the flexible support frame to obtain the triboelectric nanogenerator.

[0016] Preferably, the cellulose acetate solution in step 1) contains 7% to 10% cellulose acetate by mass.

[0017] More preferably, the cellulose acetate solution in step 1) contains 8% to 9% by mass of cellulose acetate.

[0018] Preferably, the soaking time in step 1) is 10s to 15s.

[0019] A wearable electronic device comprising the aforementioned triboelectric nanogenerator.

[0020] The working principle of the triboelectric nanogenerator of this invention is as follows: When the triboelectric nanogenerator is subjected to external pressure, the porous cellulose acetate membrane and the PVDF membrane come into contact and rub against each other, and equal amounts of positive and negative charges are formed on their surfaces. When the external force is removed, the porous cellulose acetate membrane and the PVDF membrane separate, and the change in the distance between them creates a potential difference between the first electrode layer and the second electrode layer. The potential difference drives electrons to flow in the external circuit. When the distance between the porous cellulose acetate membrane and the PVDF membrane reaches its maximum, the electric field no longer changes, electrostatic equilibrium is reached, the flow of electrons stops, and the current disappears. When the triboelectric nanogenerator is subjected to external pressure again, the porous cellulose acetate membrane and the PVDF membrane come into contact and rub against each other again under the action of external force, the electric field strength increases, and electrons in the external circuit flow back until the porous cellulose acetate membrane and the PVDF membrane come into contact again.

[0021] The beneficial effects of the present invention are: the triboelectric nanogenerator of the present invention has the advantages of light weight, good flexibility and high stability, and its preparation method is simple, the production cost is low and the equipment requirements are low, making it suitable for large-scale production and application.

[0022] Specifically:

[0023] 1) The porous cellulose acetate membrane in the triboelectric nanogenerator of the present invention has a single-layer double-sided asymmetric structure. One side of the membrane has nanoscale micropores and the other side has micron-scale micropores. It has high porosity and a relatively closed pore structure. The triboelectric nanogenerator made from it has a larger effective friction area during the friction process and the inner pores can generate additional charges, resulting in excellent output performance and stability.

[0024] 2) The triboelectric nanogenerator of the present invention has good flexibility, is easy to fold and bend, and has high sensitivity. It can be integrated with other flexible electronic devices for self-powered or wearable applications, and can also be assembled with other bio-friendly triboelectric negative electrode materials to form an environmentally friendly triboelectric nanogenerator.

[0025] 3) The preparation method of the triboelectric nanogenerator of the present invention is simple, has a short preparation cycle, low production cost, and low equipment requirements, making it suitable for large-scale production and application. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the triboelectric nanogenerator in this invention.

[0027] Explanation of reference numerals in the attached figures: 10, first electrode layer; 20, first friction layer; 30, second friction layer; 40, second electrode layer; 50, flexible support frame.

[0028] Figure 2 This is a schematic diagram illustrating the working mechanism of the triboelectric nanogenerator in this invention.

[0029] Figure 3 SEM images of the porous cellulose acetate membranes in Example 1 and Comparative Example 2.

[0030] Figure 4 The graph shows the open-circuit voltage test results of the triboelectric nanogenerators in Examples 1-2 and Comparative Examples 1-2 at a frequency of 4Hz and an applied force of 9N.

[0031] Figure 5 The graph shows the stability test results of the triboelectric nanogenerator in Example 1 at a frequency of 4 Hz and an applied force of 9 N.

[0032] Figure 6 The graph shows the test results of the power generation capacity of the triboelectric nanogenerator in Example 1. Detailed Implementation

[0033] The present invention will be further explained and described below with reference to specific embodiments.

[0034] The polyvinylidene fluoride (PVDF) membranes in Examples 1-2 and Comparative Examples 1-2 were prepared by the following method: 1 g of PVDF particles were added to 10 mL of N,N-dimethylformamide (DMF), stirred at 60 °C until completely dissolved, allowed to stand for 5 min to remove air bubbles, then dropped onto a clean petri dish, and then placed in an oven at 60 °C for 1 h to obtain a PVDF membrane (thickness of 50 μm).

[0035] Example 1:

[0036] A triboelectric nanogenerator (structural schematic shown) Figure 1 As shown in the diagram, the working mechanism is illustrated below. Figure 2 As shown, it consists of a first friction unit, a second friction unit, and a flexible support frame 50; the first friction unit consists of a first electrode layer 10 and a first friction layer 20 laminated together; the second friction unit consists of a second friction layer 30 and a second electrode layer 40 laminated together; the first electrode layer 10 and the second electrode layer 40 are both fixed on the flexible support frame 50; the first friction layer 20 and the second friction layer 30 are arranged facing each other, but they are not in direct contact; the first friction layer 20 is a porous cellulose acetate membrane; the second friction layer 30 is a polyvinylidene fluoride membrane.

[0037] The above-mentioned method for preparing triboelectric nanogenerators includes the following steps:

[0038] 1) Add 1.8787g of cellulose acetate powder to a mixed solution of acetone and deionized water in a volume ratio of 4:1, and stir for 50min at a speed of 1500r / min and a temperature of 60℃. Let it stand and cool to room temperature to obtain a cellulose acetate solution with a mass fraction of 7%.

[0039] 2) The cellulose acetate solution was evenly dripped into the petri dish and left to stand in the air for 8 seconds. Then, the petri dish was quickly placed vertically into a beaker containing deionized water for 15 seconds. The petri dish was then placed in an oven at 50°C for 8 minutes to obtain a porous cellulose acetate membrane (thickness of 40 μm, with micropores of 1 μm to 5 μm on one side and micropores of 15 nm to 30 nm on the other side).

[0040] 3) Cut both the porous cellulose acetate membrane and the PVDF membrane into sheets with a size of 2.5cm × 2.5cm. Then, attach copper foil to one side of each sheet. Connect copper wires to the two copper foil sheets. Then, attach and fix the two copper foil sheets to a PET film with a width of 2.5cm and a thickness of 100μm. Place the porous cellulose acetate membrane and the PVDF membrane face to face and keep a distance of 1.5cm between them to obtain the triboelectric nanogenerator.

[0041] Example 2:

[0042] A triboelectric nanogenerator (same as Example 1 except for the first triboelectric layer) is prepared by the following steps:

[0043] 1) Add 2.1704g of cellulose acetate powder to a mixed solution of acetone and deionized water in a volume ratio of 4:1, and stir for 50min at a speed of 1500r / min and a temperature of 60℃. Let it stand and cool to room temperature to obtain a cellulose acetate solution with a mass fraction of 8%.

[0044] 2) The cellulose acetate solution was evenly dripped into the petri dish, left to stand in the air for 8 seconds, and then the petri dish was quickly placed vertically into a beaker containing deionized water for 15 seconds. The petri dish was then placed in an oven at 50°C for 8 minutes to obtain a porous cellulose acetate membrane (thickness of 45 μm, with micropores of 1 μm to 5 μm on one side and micropores of 15 nm to 30 nm on the other side).

[0045] 3) Cut both the porous cellulose acetate membrane and the PVDF membrane into sheets with a size of 2.5cm × 2.5cm. Then, attach copper foil to one side of each sheet. Connect copper wires to the two copper foil sheets. Then, attach and fix the two copper foil sheets to a PET film with a width of 2.5cm and a thickness of 100μm. Place the porous cellulose acetate membrane and the PVDF membrane face to face and keep a distance of 1.5cm between them to obtain the triboelectric nanogenerator.

[0046] Comparative Example 1:

[0047] A triboelectric nanogenerator (same as Example 1 except for the first triboelectric layer) is prepared by the following steps:

[0048] 1) Add 2.1704g of cellulose acetate powder to acetone, and then stir for 50min at a speed of 1500r / min and a temperature of 60℃. Let it stand and cool to room temperature to obtain a cellulose acetate solution with a mass fraction of 8%.

[0049] 2) The cellulose acetate solution was evenly dropped into the petri dish, left to stand in the air for 8 seconds, and then the petri dish was placed in an oven at 50°C for 8 minutes to obtain a cellulose acetate membrane (thickness of 65 μm, non-porous).

[0050] 3) Cut both the cellulose acetate membrane and the PVDF membrane into sheets with a size of 2.5cm × 2.5cm. Then, attach copper foil to one side of each sheet. Connect copper wires to the two copper foil sheets. Then, attach and fix the two copper foil sheets to a PET film with a width of 2.5cm and a thickness of 100μm. Set the cellulose acetate membrane and the PVDF membrane face to face and keep a distance of 1.5cm between them to obtain the triboelectric nanogenerator.

[0051] Comparative Example 2:

[0052] A triboelectric nanogenerator (same as Example 1 except for the first triboelectric layer) is prepared by the following steps:

[0053] 1) Add 2.1704g of cellulose acetate powder to a mixed solution of acetone and deionized water in a volume ratio of 4:1, and stir for 50min at a speed of 1500r / min and a temperature of 60℃. Let it stand and cool to room temperature to obtain a cellulose acetate solution with a mass fraction of 8%.

[0054] 2) The cellulose acetate solution was evenly dropped into a petri dish, left to stand in the air for 8 seconds, and then placed in an oven at 50°C for 8 minutes to obtain a porous cellulose acetate membrane (thickness of 60 μm, with micropores on only one side, and pore size of 0.8 μm to 2 μm).

[0055] 3) Cut both the porous cellulose acetate membrane and the PVDF membrane into sheets with a size of 2.5cm × 2.5cm. Then, attach copper foil to one side of each sheet. Connect copper wires to the two copper foil sheets. Then, attach and fix the two copper foil sheets to a PET film with a width of 2.5cm and a thickness of 100μm. Place the porous cellulose acetate membrane and the PVDF membrane face to face and keep a distance of 1.5cm between them to obtain the triboelectric nanogenerator.

[0056] Performance testing:

[0057] 1) Scanning electron microscope (SEM) images of the surface and back sides of the porous cellulose acetate membranes in Example 1 and Comparative Example 2 are shown below. Figure 3 (The area within the black box is a magnified view.)

[0058] Depend on Figure 3It can be seen that: the porous cellulose acetate membrane in Example 1 has nanoscale micropores (pore size of 15nm to 30nm) on one side and micron-scale micropores (pore size of 1μm to 5μm) on the other side, with high porosity and relatively closed pore structure, while the porous cellulose acetate membrane in Comparative Example 2 has micropores on only one side, with a pore size of 0.8μm to 2μm.

[0059] Furthermore, tests (same as in Example 1) revealed that the microstructure of the porous cellulose acetate membrane in Example 2 was very similar to that of the porous cellulose acetate membrane in Example 1.

[0060] 2) The open-circuit voltage test results of the triboelectric nanogenerators in Examples 1-2 and Comparative Examples 1-2 at a frequency of 4Hz and an applied force of 9N are shown in the figure below. Figure 4 As shown.

[0061] Depend on Figure 4 It can be seen that the open-circuit voltages of the triboelectric nanogenerators in Example 1 and Example 2 are 248V and 288V, respectively, while the open-circuit voltages of the triboelectric nanogenerators in Comparative Example 1 and Comparative Example 2 are 128V and 184V, respectively. Compared with the triboelectric nanogenerators in Comparative Example 1 and Comparative Example 2, the open-circuit voltage of the triboelectric nanogenerator in Example 2 is increased by 125% and 56.5%, respectively.

[0062] 3) The stability test results of the triboelectric nanogenerator in Example 1 at a frequency of 4Hz and an applied force of 9N are shown in the figure below. Figure 5 As shown.

[0063] Depend on Figure 5 It can be seen that the open-circuit voltage of the triboelectric nanogenerator in Example 1 hardly decreased after 10,000 cycles, indicating that it has good stability.

[0064] Furthermore, tests (same as in Example 1) revealed that the triboelectric nanogenerator in Example 2 also exhibits excellent stability.

[0065] 4) The triboelectric nanogenerator from Example 1 was connected to several LED beads connected in series. The power generation capacity test results are shown in the figure below. Figure 6 As shown.

[0066] Depend on Figure 6 It can be seen that the triboelectric nanogenerator in Example 1 has high energy conversion efficiency and can light up 140 commercially available LED beads connected in series.

[0067] Furthermore, tests (same as in Example 1) revealed that the triboelectric nanogenerator in Example 2 also exhibits excellent power generation capabilities.

[0068] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A triboelectric nanogenerator, characterized in that, Its components include a first friction unit, a second friction unit, and a flexible support frame; the first friction unit comprises a first electrode layer and a first friction layer laminated together; the second friction unit comprises a second electrode layer and a second friction layer laminated together; both the first electrode layer and the second electrode layer are fixed on the flexible support frame; the first friction layer and the second friction layer are arranged face to face, but do not directly contact each other; the first friction layer is a porous cellulose acetate membrane; the second friction layer is a polyvinylidene fluoride membrane; one side of the porous cellulose acetate membrane has micropores with a pore size of 1μm to 5μm, and the other side has micropores with a pore size of 15nm to 30nm.

2. The triboelectric nanogenerator according to claim 1, characterized in that: The distance between the first friction layer and the second friction layer is 1cm to 2cm.

3. The triboelectric nanogenerator according to claim 1 or 2, characterized in that: The thickness of the first friction layer is 40μm to 50μm.

4. The triboelectric nanogenerator according to claim 1 or 2, characterized in that: The thickness of the second friction layer is 50μm to 60μm.

5. The triboelectric nanogenerator according to claim 1 or 2, characterized in that: Both the first electrode layer and the second electrode layer are copper foil.

6. The triboelectric nanogenerator according to claim 1 or 2, characterized in that: The flexible support frame is a polyethylene terephthalate film.

7. A method for preparing a triboelectric nanogenerator as described in any one of claims 1 to 6, characterized in that, Includes the following steps: 1) A cellulose acetate solution is coated onto a substrate to form a film, and then soaked in water to obtain a porous cellulose acetate membrane; a polyvinylidene fluoride solution is coated onto a substrate to form a film to obtain a polyvinylidene fluoride membrane. 2) The first electrode layer is adhered to the surface of the porous cellulose acetate membrane, and the second electrode layer is adhered to the surface of the polyvinylidene fluoride membrane. The porous cellulose acetate membrane and the polyvinylidene fluoride membrane are then placed face to face and kept from contact. The first electrode layer and the second electrode layer are then fixed on the flexible support frame to obtain the triboelectric nanogenerator.

8. The preparation method according to claim 7, characterized in that: In step 1), the cellulose acetate solution contains 7% to 10% cellulose acetate by mass; the soaking time in step 1) is 10 to 15 seconds.

9. A wearable electronic device, characterized in that, It includes the triboelectric nanogenerator according to any one of claims 1 to 6.

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