Nanometer composite film and nanometer electrostatic generator using same

Abstract

The invention discloses a nano-composite film, which is characterized in that a PVDF-HFP nano-fiber composite film doped with covalent organic framework materials and carbon nanotubes (TPTP-COF-f-CNT) is prepared by an electrostatic spinning technology to serve as a negative friction layer, a thermoplastic polyurethane (TPU) nano-fiber film is prepared to serve as a positive friction layer, and an electrostatic generator (TENG) in a vertical contact separation mode is formed by assembling the PVDF-HFP nano-fiber composite film and the TPTP-COF-f-CNT nano-fiber composite film and the TPTP-COF-f-CNT nano-fiber composite film. In the electrostatic generator, the TPTP-COF (at) f-CNT is doped in the negative friction layer PVDF-HFP nanofiber membrane, so that the surface charge density and the contact area of the negative friction layer can be improved, and the electrostatic generator with high output voltage and short-circuit current is obtained.

Description

Technical Field

[0001] The present invention relates to a nano composite film and an electrostatic generator using the same. Background Art

[0002] In order to increase the power generation current and power generation voltage of the electrostatic generator, polyvinylidene fluoride-co-hexafluoropropylene is usually added to the negative film friction layer. Nano-inorganic materials such as barium titanate and carbon nanotubes are mixed into polyvinylidenefluoride-hexafluoropropylene (PVDF-HFP) films, but there are still limitations in improving electrical properties.

[0003] In view of this, the inventor of this case conducted in-depth research, which led to the creation of this case. Summary of the Invention

[0004] The object of the present invention is to provide a nanocomposite film that can improve the electrical properties of an electrostatic generator.

[0005] Another object of the present invention is to provide an electrostatic generator with improved electrical properties.

[0006] In order to achieve the above object, the technical solution of the present invention is: A nanocomposite film, wherein the preparation method of the nanocomposite film is as follows: adding a certain proportion of TPTP-COF@f-CNT powder to a PVDF-HFP solution to obtain a TPTP-COF@f-CNT / PVDF-HFP electrospinning solution, The amount of TPTP-COF@f-CNT powder added is 0.05-20.0 wt.% of the PVDF-HFP powder added to the PVDF-HFP solution; the TPTP-COF@f-CNT / PVDF-HFP electrospinning solution is then electrospun to obtain a TPTP-COF@f-CNT / PVDF-HFP composite film; The TPTP-COF@f-CNT powder was prepared as follows: TPTP-COF reaction monomers and acidified carbon nanotubes f-CNTs were added to a reaction vessel, wherein the amount of acidified carbon nanotubes f-CNTs added was 5.0 to 40.0 wt. % of the total weight of the TPTP-COF reaction monomers. The TPTP-COF reaction monomers include 2,4,6-tris(4-aminophenyl)-1,3,5-triazine TPT-3NH2 and 2,4,6-tris(4-carboxyphenyl)-1,3,5-triazine TPT-3CHO. During the synthesis of the TPTP-COF@f-CNT powder, 2,4,6-tris(4-aminophenyl)-1,3,5-triazine TPT-3NH2 and 2,4,6-tris(4-carboxyphenyl)-1,3,5-triazine TPT-3CHO are added in equal moles. Then, 1-10 ml of 1,4-dioxane and 1-10 ml of trimethylbenzene were added, followed by 0.5-5 ml of acetic acid with a concentration of 3-9 mol / L. The reaction vessel was sealed and the gas was purged while maintaining the vacuum condition in the reaction vessel. The reaction vessel was heated to 120°C and reacted for 3 days. After the reaction was completed, the purified covalent organic framework / carbon nanotube composite material TPTP-COF@f-CNT was finally dried under vacuum to obtain TPTP-COF@f-CNT powder.

[0007] Furthermore, the preparation process of the TPTP-COF@f-CNT powder is as follows: 0.15 mmol of 2,4,6-tris(4-aminophenyl)-1,3,5-triazine TPT-3NH2, 0.15 mmol of 2,4,6-tris(4-carboxyphenyl)-1,3,5-triazine TPT-3CHO, and 5.0 wt.% to 15.0 wt.% of the total weight of the TPTP-COF reaction monomers were added to a reaction bottle, and 5 ml of 1,4-dioxane and 5 ml of trimethylbenzene were added, followed by the addition of 1.2 ml of a 6.0 molar concentration of 1,4-dioxane. mol / L acetic acid, and then the reaction bottle was sealed and the gas was purged while maintaining the vacuum inside the container. The reaction bottle was heated to 120°C for 3 days. After the reaction was completed, it was purified using tetrahydrofuran, acetone and methanol to collect the green solid covalent organic framework / carbon nanotube composite material TPTP-COF@f-CNT, which was then dried under vacuum to obtain TPTP-COF@f-CNT powder with a yield of 70%.

[0008] Furthermore, the preparation method of the nanocomposite film is as follows: 3 g of PVDF-HFP powder is added to 12 mL of dimethylformamide, doped with TPTP-COF@f-CNT powder to obtain a mixed solution, and the mixed solution is placed in an ultrasonic oscillation for 1 hour before electrospinning, and stirred in an oil bath at 60°C until the mixed solution is completely dissolved to obtain a TPTP-COF@f-CNT / PVDF-HFP electrospinning solution, and the TPTP-COF@f-CNT / PVDF-HFP electrospinning solution is placed in a 10 mL syringe, and a roller is used to collect nanofibers. The TPTP-COF@f-CNT / PVDF-HFP electrospinning solution is pushed out using the syringe, and the electrospinning operating parameters are set as follows: operating voltage 13-14 kV, flow rate: 1.4 ml / hr, metal roller speed of 1500 rpm, temperature: 27.5°C±2.5°C and humidity 45±5%, and electrospinning is performed for 4 hrs. The nanofiber membrane was then collected and dried in a vacuum oven set at 60°C for 6 hours to remove the DMF residue to obtain the TPTP-COF@ f-CNT / PVDF-HFP composite film.

[0009] Furthermore, the addition amount of TPTP-COF@f-CNT is 0.5 wt.%~2.0 wt.% of the total weight of PVDF-HFP powder.

[0010] Furthermore, during the synthesis of the TPTP-COF@f-CNT powder, the amount of acidified carbon nanotubes f-CNTs added is 5.0 wt.%, 10.0 wt.%, or 15.0 wt.% of the total weight of the TPTP-COF reactive monomers; and the amount of TPTP-COF@f-CNTs added is 0.5 wt.%, 1.0 wt.%, 1.5 wt.%, or 2.0 wt.% of the total weight of the PVDF-HFP powder.

[0011] An electrostatic generator comprises a positive friction layer and a negative friction layer, wherein the negative friction layer comprises the nanocomposite film according to any one of claims 1 to 5, and the positive friction layer comprises a TPU layer, wherein the TPU layer adopts a thermoplastic polyurethane TPU nanofiber membrane. Furthermore, the preparation process of the thermoplastic polyurethane TPU nanofiber membrane is as follows: a certain amount of thermoplastic polyurethane TPU is added and dissolved in an organic solvent to form a TPU electrospinning solution, and the added amount of thermoplastic polyurethane TPU is 5.0-20.0 wt.% of the TPU electrospinning solution, and then the TPU electrospinning solution is spun to obtain the thermoplastic polyurethane TPU nanofiber membrane.

[0012] Furthermore, the preparation process of the thermoplastic polyurethane (TPU) nanofiber membrane is as follows: 1.2 g of thermoplastic polyurethane is weighed and dissolved in 9.640 mL of a dimethylformamide / tetrahydrofuran mixed solvent to form a TPU mixed solution, wherein the volume ratio of dimethylformamide / tetrahydrofuran in the mixed solvent is 1:1; the TPU mixed solution is then placed in a 70°C oil bath and stirred for 12 hours until the TPU mixed solution is completely dissolved to form a TPU electrospinning solution; The TPU electrospinning solution was placed in a 10 mL syringe, and a roller was used to collect the nanofibers. The TPU electrospinning solution was pushed out through the syringe, and the electrospinning operating parameters were set as follows: operating voltage 11-12 kV, flow rate: 1.4 ml / hr, metal roller speed of 1500 rpm, temperature: 28.0°C ± 2.5°C and humidity 45 ± 5%. After electrospinning for 4 hrs, the nanofiber membrane was collected and placed in a vacuum oven set at 60°C for 6 hrs to remove DMF / THF residues.

[0013] Furthermore, the electrostatic generator is an electrostatic generator in a vertical contact separation mode, the positive friction layer also includes a first PP layer and a first conductive layer, the first conductive layer is connected between the first PP layer and the TPU layer; the negative friction layer also includes a second PP layer and a second conductive layer, the second conductive layer is connected between the second PP layer and the nano-composite film, the first PP layer and the second PP layer are spaced apart to form a sandwich, a spacer is provided between the first PP layer and the second PP layer, the nano-composite film and the TPU layer are arranged opposite to each other, and the two are respectively located in the sandwich.

[0014] After adopting the above technical solution, the present invention has the following beneficial effects: This invention describes an electrostatic generator (TENG) that utilizes electrospinning technology to fabricate a PVDF-HFP nanofiber composite film containing a covalent organic framework material and carbon nanotubes (TPTP-COF@f-CNT) as the negative friction layer and a thermoplastic polyurethane (TPU) nanofiber film as the positive friction layer. These composite films are assembled into a triboelectric nanogenerator (TENG) with a vertical contact-separation mode. By doping the PVDF-HFP nanofiber film with TPTP-COF@f-CNT in the negative friction layer, the surface charge density and contact area of the negative friction layer are increased, resulting in a TENG with high output voltage and short-circuit current.

[0015] Scanning electron microscopy revealed that the nanofiber diameter increases and then decreases with increasing TPTP-COF@f-CNT content, which contributes to an increase in the film's specific surface area. X-ray diffraction patterns revealed that the proportion of phase crystals in the PVDF-HFP nanofiber membrane increased with increasing TPTP-COF@f-CNT concentration from 0, 0.5, 1.0, 1.5, and 2.0 wt. %. However, above 1.0 wt. %, the proportion of phase crystals decreased. Compared to samples containing TPTP-COF, films containing TPTP-COF@f-CNT exhibited a higher phase content. Compared to the TPTP-COF / PVDF-HFP TENG, the TPTP-COF@f-CNT / PVDF-HFP TENG exhibited superior tribological performance. After 20,000 cycles of stability testing, the TPTP-COF@f-CNT / PVDF-HFP TENG demonstrated excellent power generation stability. Furthermore, the TPTP-COF@f-CNT / PVDF-HFP TENG was able to instantly illuminate 100 commercial red LEDs and drive an electronic watch. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 The chemical structural formula of the TPTP-COF@f-CNT powder of the present invention is: Figure 2 Schematic diagram of the structure of the electrostatic generator of the present invention; Figure 3 is the chemical structural formula of the TPTP-COF powder of the present invention; Figure 4 Scanning electron microscopy (SEM) images [(a) TPTP-COF, (b) TPTP-COF@f-CNT] and dynamic particle size analysis (DLS) images [(c) TPTP-COF, (d) TPTP-COF@f-CNT] of the present invention; Figure 5 SEM images [(a) TPU, (b) PVDF-HFP, (c) TPTP-COF (1.0 wt.%) / PVDF-HFP] nanofiber membranes and diameter analysis [(d) TPU, (e) PVDF-HFP, (f) TPTP-COF / PVDF-HF; Figure 6 SEM images of TPTP-COF@f-CNT / PVDF-HFP nanofiber membranes [(a) 0.5 wt. %, (c) 1.0 wt. %] and diameter analysis [ (b) 0.5 wt. %, (d) 1.0 wt. %]; Figure 7 SEM images of TPTP-COF@f-CNT / PVDF-HFP nanofiber membrane [ (e) 1.5 wt.%, (g) 2.0 wt.%] and diameter analysis [ (f) 1.5 wt.%, (h) 2.0 wt.%]; Figure 8 X-ray diffraction patterns of TPTP-COF (1.0 wt.%) / PVDF-HFP and TPTP-COF@f-CNT / PVDF-HFP nanofiber membranes; Figure 9 Schematic diagram of the TPTP-COF@f-CNT / PVDF-HFP TENG operation; Figure 10 (a) Open-circuit voltage and (b) short-circuit current of the TPTP-COF@ f-CNT / PVDF-HFP TENG at 5 Hz and different applied forces (10, 20, 30, 40, 50, 60, and 70 N); (c) open-circuit voltage and (d) short-circuit current at 60 N and operating frequencies (1, 2, 3, 4, and 5 Hz); Figure 11 TPTP-COF (1.0 wt.%) / PVDF-HFP (a) Open-circuit voltage (b) short-circuit current and (c) transferred charge of TPTP@f-CNT / PVDF-HFPTENG at 60 N and 5 Hz.

[0017] Figure 12 (a) Average open-circuit voltage and (b) average short-circuit current of TPTP-COF@f-CNT / PVDF-HFP and TPTP-COF / PVDF-HFP TENG at 60 N and different operating frequencies (1, 2, 3, 4, and 5 Hz).

[0018] Figure 13 (a) Open-circuit voltage, short-circuit current (b) power density, and stable cycling tests of TPTP-COF / PVDF-HFP and TPTP-COF@f-CNT / PVDF-HFP TENGs with different load resistances at 60 N and 5 Hz (c) TPTP-COF / PVDF-HFP (d) TPTP-COF@f-CNT / PVDF-HFP TENG. DETAILED DESCRIPTION

[0019] In order to further explain the technical solution of the present invention, the present invention is described in detail below through specific embodiments.

[0020] 1. Preparation Example 1 The present invention provides a method for preparing TPTP-COF@f-CNT powder, comprising the following steps: adding dried 2,4,6-tris(4-aminophenyl)-1,3,5-triazine TPT-3NH2 (58.97 mg, 0.15 mmol), dried 2,4,6-tris(4-carboxyphenyl)-1,3,5-triazine TPT-3CHO (53.124 mg, 0.15 mmol) and dried acidified carbon nanotubes into a 25 ml single-necked flask; f - CNT, acidified carbon nanotubes f The addition amount of -CNT is 5 wt.%, 10 wt.% or 15 wt.% of the total weight of TPTP-COF reaction monomers (including 2,4,6-tris(4-aminophenyl)-1,3,5-triazine TPT-3NH2 and 2,4,6-tris(4-carboxyphenyl)-1,3,5-triazine TPT-3CHO).

[0021] Add 5 ml of 1,4-dioxane and 5 ml of mesitylene, followed by 1.2 ml of 6 mol / L acetic acid (HoAc). Seal the reaction flask, remove the gas, and maintain the vacuum inside the container. Heat the reaction flask to 120 o C for 3 days. After the reaction, tetrahydrofuran (THF), acetone (Acetone), and methanol (MeOH) were used for purification to collect the green solid covalent organic framework / carbon nanotube composite material TPTP-COF@f-CNT (chemical structure as shown in Figure 1 The product was dried under vacuum (yield = 70%).

[0022] Example 2 The present invention provides a nanocomposite film, specifically a TPTP-COF@f-CNT / PVDF-HFP composite film. The preparation method of the nanocomposite film comprises the following steps: weighing 3 g of PVDF-HFP powder and dissolving it in 12 mL of dimethylformamide (DMF); then doping the mixture with 0.5, 1.0, 1.5, or 2.0 wt% of TPTP-COF@f-CNT powder relative to the total weight of PVDF-HFP to obtain a mixed solution, thereby preventing particle precipitation. The TPTP-COF@f-CNT powder used is the TPTP-COF@f-CNT powder prepared in Example 1.

[0023] Before electrospinning, the mixed solution was ultrasonically shaken for 1 hour and stirred in a 60°C oil bath until the mixed solution was completely dissolved, obtaining the TPTP-COF@ f-CNT / PVDF-HFP electrospinning solution. The TPTP-COF@ f-CNT / PVDF-HFP electrospinning solution was placed in a 10mL syringe, and the nanofibers were collected using a roller. The electrospinning solution was then pushed out with the syringe. The electrospinning parameters were as follows: operating voltage 13-14 kV, flow rate 1.4 ml / hr, metal roller speed 1500 rpm, temperature 27.5°C ± 2.5°C, and humidity 45 ± 5%. After 4 hours of electrospinning, the nanofiber membranes were collected and dried in a vacuum oven set at 60°C for 6 hours to remove any residual DMF.

[0024] Example 3 The present invention discloses a method for preparing a thermoplastic polyurethane (TPU) nanofiber membrane, comprising the following steps: weighing 1.2 g of thermoplastic polyurethane (TPU) and dissolving it in 9.640 mL of a dimethylformamide / tetrahydrofuran (DMF / THF) mixed solution (with a DMF / THF volume ratio of 1:1); placing the mixed solution in a 70°C oil bath and stirring for 12 hours until the TPU electrospinning solution is completely dissolved. The TPU electrospinning solution is placed in a 10 mL syringe, and a roller is used to collect the nanofibers. The syringe is then used to push the electrospinning solution out. The electrospinning operating parameters are as follows: operating voltage 11-12 kV, flow rate 1.4 ml / hr, metal roller speed 1500 rpm, temperature 28.0°C ± 2.5°C, and humidity 45 ± 5%. After 4 hours of electrospinning, the nanofiber membrane is collected and dried in a vacuum oven set at 60°C for 6 hours to remove any residual DMF / THF.

[0025] Example 4 An electrostatic generator, such as Figure 2 As shown, it includes a positive friction layer and a negative friction layer. The positive friction layer includes the thermoplastic polyurethane TPU nanofiber membrane (hereinafter referred to as TPU membrane) of the above-mentioned embodiment 3, specifically the TPU layer 11, and the negative friction layer includes the nanocomposite film of the above-mentioned embodiment 2, specifically the nanocomposite film layer.

[0026] The positive friction layer also includes a first PP layer and a first conductive layer, with the first conductive layer connected between the first PP layer and the TPU layer. The negative friction layer also includes a second PP layer and a second conductive layer, with the second conductive layer connected between the second PP layer and the nanocomposite film layer. The first and second PP layers are spaced apart, forming a sandwich. A spacer is provided between the first and second PP layers. The nanocomposite film layer and the TPU layer are positioned opposite each other, both located within the sandwich.

[0027] The first conductive layer is specifically a copper foil layer, and the second conductive layer is specifically a copper foil layer.

[0028] Specifically, the TPU membrane and TPTP-COF@f-CNT / PVDF-HFP nanofiber membrane were cut into 3×2 , and a TPU layer 11 and a nanofiber film layer are formed accordingly.

[0029] Glue the same size copper foil electrode to one side of the TPU layer 11, and glue it to the 5×4 The positive friction layer was formed on a polypropylene (PP) substrate and a copper foil electrode of the same size was adhered to one side of the nanofiber film layer, together with a copper foil electrode adhered to a 7×13 cm 2 A polypropylene (PP) substrate is used as the negative friction layer, and 1 cubic centimeter polyurethane PU film is cut as a spacer as a supporting material and glued to the four corners of the PP board.

[0030] Comparative Example 1 A method for preparing TPTP-COF powder comprises the following steps: A 25 ml reaction flask was charged with dried 2,4,6-tris(4-aminophenyl)-1,3,5-triazine (2,4,6-tris(4-aminophenyl)triazine) TPT-3NH2 (58.97 mg, 0.15 mmol) and dried 2,4,6-tris(4-carboxyphenyl)-1,3,5-triazine (2,4,6-tris(4-formylphenyl)-1,3,5-triazine) TPT-3CHO (53.124 mg, 0.15 mmol), 1,4-dioxane (10 ml) and mesitylene (10 ml), followed by acetic acid (HoAc) (1.2 ml, 6 molar concentration). mol / L). After sealing the reaction bottle, remove the gas and keep the container vacuum. Heat the reaction bottle to 120 o C for 3 days. After the reaction, tetrahydrofuran (THF), acetone (Acetone), and methanol (MeOH) were used for purification to collect the yellow solid covalent organic framework / nanocarbon tube composite material TPTP-COF (chemical structure as shown in Figure 3 The product was dried under vacuum (yield = 85%).

[0031] Comparative Example 2 A method for preparing a TPTP-COF / PVDF-HFP composite film comprises the following steps: weighing PVDF-HFP (3 g) and dissolving it in DMF (12 mL); doping the mixture with 1.0 wt.% TPTP powder relative to the total weight of PVDF-HFP to prevent particle precipitation; subjecting the mixed solution to ultrasonic vibration for 1 hour before electrospinning; and stirring in a 60°C oil bath until the TPTP-COF / PVDF-HFP electrospinning solution is completely dissolved; placing the solution in a 10 mL syringe, collecting nanofibers using a roller, and ejecting the electrospinning solution with the aid of the syringe; the electrospinning operating parameters are as follows: operating voltage 13-14 kV, flow rate: 1.4 ml / hr, metal roller speed of 1500 rpm, needle, temperature: 27.5°C ± 2.5°C, and humidity 45 ± 5%. After electrospinning for 4 hours, the nanofiber film is collected and dried in a vacuum oven set at 60°C for 6 hours to remove DMF residue.

[0032] 2. Test (1) Field emission electron microscopy analysis of TPTP-COF@f-CNT. The results are as follows: Figure 4 shown.

[0033] Field emission electron microscopy was used to analyze and observe the surface morphology of TPTP-COF and TPTP-COF@f-CNT. Figure 4 (a) The TPTP-COF shown in FIG. Figure 4 (b) shows that when f-CNTs are added, TPTP-COF particles grow along the f-CNT fibers due to their fibrous nature, affecting the agglomeration of TPTP-COF@f-CNTs. Furthermore, f-CNTs, which contain COOH functional groups, can better disperse the surface of TPTP-COF. 1 mg of TPTP-COF and TPTP-COF@CNTs were dissolved in 10 mL of DMF. After dynamic light scattering analysis and ultrasonic treatment, the average particle size of TPTP-COF was 382.25 μm. 75.50 nm, and the average particle size of TPTP-COF@CNT is 418.57 102.56 nm, consistent with the SEM image.

[0034] (2) Field emission electron microscopy analysis of nanofibers shows the following results: Figure 5 shown Field emission electron microscopy was used to analyze and observe the surface morphology of electrospun TPU and PVDF-HFP nanofiber molds. Figure 5 (a) and (d) are the surfaces of TPU electrospun fibers. The surfaces are very smooth and the average diameter of the fiber membrane is 1.37 0.267 m. Figure 5 (b) and (e) PVDF-HFP fiber membranes without any doping materials have no beading effect and the average diameter of the fiber membrane is 0.349 0.108 m. Figure 5 (c) and (f) show the SEM images of TPTP-COF / PVDF-HFP films doped with 1.0 wt.% TPTP-COF. Figure 6 and Figure 7 The SEM images of TPTP-COF@f-CNT / PVDF-HFP nanofiber membranes doped with different TPTP-COF@f-CNT concentrations (0.5, 1.0, 1.5, and 2.0 wt. %) show that the average diameter of the fiber membrane first increases and then decreases with the increase of TPTP-COF@f-CNT concentration. The reason is that the electrospinning flow rate is fixed, the PVDF-HFP solution decreases with increasing concentration, and the conductivity increases when it exceeds the critical concentration threshold. The electrostatic force between the collector and the syringe spinneret will increase, so the nanofibers will be pulled thinner and longer. Figure 6 and Figure 7 This is the SEM image of TPTP-COF@f-CNT / PVDF-HFP nanofiber membrane. The addition of TPTP-COF@f-CNT reduces the average diameter of the fiber membrane.

[0035] (3) X-ray diffraction analysis of nanofiber membranes like Figure 8 As shown in Table 1, it was observed that PVDF-HFP = 17.8, 18.4, 19.9 and 20.30, corresponding to Phase (100), (020), (110) and (200 / 110) plane diffraction peak, in TPTP-COF@f-CNT / PVDF-HFP nanofiber membranes doped with different concentrations of TPTP-COF@f-CNT, The PVDF-HFP crystal content increases with the TPTP-COF@f-CNT to a critical value. The content decreases with the increase of TPTP-COF@f-CNT. When the content of TPTP-COF@f-CNT is 1.0wt.%, The maximum content is beneficial to the triboelectric output of TENG.

[0036] Table 1. The proportion of various crystal phases in the X-ray diffraction patterns (XRD) of TPTP-COF / PVDF-HFP and TPTP-COF@f-CNT / PVDF-HFP nanofiber membrane composite fibers

[0037] (4) Measurement of electrostatic properties of PVDF-HFP / TPTP@ f-CNT This study uses a dual-electrode vertical contact-separation mode to convert triboelectric mechanical energy into electrical energy. Figure 9 As shown in the figure, in the initial state, there is no charge on the surface of the TPTP-COF@f-CNT / PVDF-HFP and TPU nanofiber membranes, and there is no potential difference between the two electrodes. (I) When an external force is applied, the TPTP-COF@f-CNT / PVDF-HFP nanofiber membrane contacts the TPU nanofiber membrane, and the contact causes electrification. Due to the difference in electron affinity, negative charge is transferred from the surface of the TPU nanofiber membrane to the surface of the TPTP-COF@f-CNT / PVDF-HFP fiber membrane, generating positive charge on the surface of the TPU fiber membrane. The surfaces of the TPU and TPTP-COF@f-CNT / PVDF-HFP fiber membranes have equal but different charges. When the two materials are in contact again, the surface potential difference is zero, and no external current is generated. (II) When released by external force, the TPTP-COF@f-CNT / PVDF-HFP nanofiber membrane separates from the TPU nanofiber membrane, and the charge balance is broken. Due to the electrostatic induction effect, charges with different polarity from the nanofiber membrane are formed on the two back Cu electrodes. Due to the induction of the potential difference, electrons flow from the high-potential electrode to the low-potential electrode using the external connection circuit, generating a forward current. (III) When the distance between the TPU and the TPTP-COF@f-CNT / PVDF-HFP nanofiber membrane no longer changes, electrostatic equilibrium is achieved, the potential difference between the electrodes no longer exists, and the current in the external circuit disappears. (IV) As the TPU and TPTP-COF@f-CNT / PVDF-HFP nanofiber membrane come into contact again, electrons flow from the low-potential electrode to the high-potential electrode using the external connection circuit, generating a reverse current. Through the contact-separation process, an alternating current is generated that flows continuously between the electrodes.

[0038] The effect of different forces from 10N to 60N on the electrical properties of TPTP-COF@CNT-1.0 TENG was measured at a fixed operating frequency of 5Hz. Figure 10 As shown in (a), (b) and Table 2 below, the output voltage increases from 197.10 to 284.20 V, and the short-circuit current increases from 54.20 to 87.60 A, the contact area increases with the increase of applied force, thus obtaining more triboelectric charge, effectively assisting the output of triboelectricity. When the applied force increases to 70N, the surface of the nanofiber is damaged due to excessive applied force, resulting in a decrease in output voltage and short-circuit current. The influence of the applied force on the electrical properties of TPTP-COF@CNT-1.0 TENG is measured at a fixed applied force of 60N and an operating frequency of 1Hz to 5Hz. Figure 10 As shown in (c) and (d) and Table 3 below, the output voltage increases from 191.2 to 300.20 V, and the short-circuit current increases from 25.60 to 91.0 A increases with the operating frequency, which leads to stronger friction and more charge.

[0039] Table 2 Open circuit voltage and short circuit current of TPTP-COF@f-CNT-1.0 under different forces (10, 20, 30, 40, 50, 60 and 70 N)

[0040] Table 3 Open circuit voltage and short circuit current of TPTP-COF@f-CNT-1.0 TENG at different operating frequencies (1, 2, 3, 4, 5 Hz)

[0041] Under the working conditions of fixed force 60N and working frequency 5Hz, the output voltage, short-circuit current and transferred charge of the original PVDF-HFP, TPTP-COF and TPTP-COF@f-CNT-1.0 TENG are compared, as shown in Figure 2. Figure 11 As shown in Table 4 below, the output voltages of the original PVDF-HFP, TPTP-COF, and TPTP-COF@f-CNT-1.0 TENG are 227.7 V, 275.7 V, and 300.20 V, respectively. The short-circuit currents of the original PVDF-HFP, 1.0 wt.% doped TPTP-COF, and TPTP-COF@f-CNT-1.0 TENG are 33.76 V, 275.7 V, and 300.20 V, respectively. A. 77.4 A and 110.5 A. The transferred charge of the original PVDF-HFP, 1.0 wt.% TPTP-COF doped and TPTP@ f-CNT-1.0 TENG increased from 56.0nC, 92.3nC and 110.5nC, respectively. It is clearly shown that the addition of TPTP-COF@f-CNT has a higher negative electrode polarity than TPTP-COF. Because the higher the charge distributed on the surface of the triboelectric material, the greater the surface potential, resulting in a greater driving force for electron transfer. Indirectly improve the triboelectric output of TENG. The output voltage, short-circuit current and transferred charge of the TENG doped with different TPTP-COF@f-CNT (0.5, 1.0, 1.5, and 2.0) wt.% concentrations increased from 268.20V to 300.20V, 62.20V to 1.0wt.%, respectively. A increased to 91.0 The TPTP-COF@ f-CNT in PVDF-HFP nanofibers increased the surface charge density of the nanofibers. As the TPTP-COF@ f-CNT content increased from 1.0 wt. % to 2.0 wt. %, the output voltage, short-circuit current, and transferred charge of the TENG decreased from 300.20 V to 245.30 V and 91.0 wt. %, respectively. A dropped to 68.8 A and 110.5 nC decreased to 78.0 nC. The irregular distribution of TPTP-COF@ f-CNT in PVDF-HFP nanofibers caused by the excessive amount of TPTP-COF@ f-CNT led to a decrease in the output voltage of TENG, thus failing to effectively capture electrons.

[0042] Table 4 TPTP-COF (1.0 wt.%) / PVDF-HFP Open circuit voltage, short circuit current and transferred charge of TPTP-COF@f-CNT / PVDF-HFP TENG at 60N and 5Hz

[0043] Under a fixed applied force of 60N and different operating frequencies (1, 2, 3, 4, and 5Hz), the effects of different TPTP-COF@CNT concentrations on the electrical properties of the TPTP-COF@f-CNT / PVDF-HFP TENG were measured. Figure 12 As shown in Table 5 and Table 6 below, when the operating frequency increases from 1Hz to 5Hz, the average open circuit voltage of the original PVDF-HFP module increases from 96.31V to 221.67V, and the average short circuit current increases from 5.032 to 31.57 A. When 0.5 wt. % TPTP-COF@CNT is added, the average open circuit voltage increases from 142.57 V to 257.53 V, and the average short circuit current increases from 16.97 to 60.40 V. A. When the concentration of TPTP@f-CNT is 1.0wt.%, the average open circuit voltage and average short circuit current reach the maximum value, increasing from 173.73V to 295.70V and from 23.72 to 88.00V, respectively. A. When the TPTP@f-CNT concentration exceeds 1.0 wt %, the triboelectric output performance of the PVDF-HFP / TPTP@f-CNT TENG begins to decay, and the average open circuit voltage and average short circuit current increase from 106.64 to 234.90 V and 16.72 to 62.33 V, respectively, with the operating frequency. A. The optimal concentration of TPTP@f-CNT / PVDF-HFP in the TENG is 1.0 wt. %, which can achieve the highest electrical output.

[0044] Table 5 Average open circuit voltage of TPTP-COF@f-CNT / PVDF-HFP and TPTP-COF / PVDF-HFP TENG at 60 N and different operating frequencies (1, 2, 3, 4, and 5 Hz)

[0045] Table 6 Average short-circuit current of TPTP-COF@f-CNT / PVDF-HFP and TPTP-COF / PVDF-HFP TENG at 60 N and different operating frequencies (1, 2, 3, 4, and 5 Hz)

[0046] When applying a force of 60N and an operating frequency of 5Hz, the output voltage and short-circuit current of TPTP-COF@f-CNT and TPTP-COF@f-CNT were measured by connecting different load resistors, and the instantaneous peak power density was calculated. Figure 13 As shown in (a) and (b), when the load resistance is less than 1MΩ, the short-circuit current decreases slowly and the output voltage also increases slowly. Between 1MΩ and 100MΩ, the short-circuit current decreases rapidly and the output voltage also increases rapidly. After 100MΩ, the changes in output voltage and short-circuit current gradually become stable. When the load resistance is 150MΩ, the maximum values of the peak power density obtained are 3.4 and 6.5 respectively. The maximum peak power density is obtained from the TPTP-COF@f-CNT TENG. Since CNT has good conductivity, the TPTP-COF@f-CNT in PVDF-HFP accelerates the triboelectric charge transfer. Figure 13 As shown in (c) and (d), after 20,000 cycles of stability testing, the open circuit voltages of TPTP-COF / PVDF and TPTP-COF@f-CNT / PVDF TENGs all maintained a certain value, indicating that both TPTP-COF / PVDF and TPTP-COF@f-CNT / PVDF TENGs have excellent mechanical stability.

Claims

1. A nanocomposite film, characterized in that: The preparation method of the nanocomposite film is as follows: adding a certain proportion of TPTP-COF@f-CNT powder to a PVDF-HFP solution to obtain a TPTP-COF@f-CNT / PVDF-HFP electrospinning solution, The amount of TPTP-COF@f-CNT powder added is 0.05-20.0 wt.% of the PVDF-HFP powder added to the PVDF-HFP solution; the TPTP-COF@f-CNT / PVDF-HFP electrospinning solution is then subjected to an electrospinning operation to obtain a TPTP-COF@f-CNT / PVDF-HFP composite film; The preparation process of the TPTP-COF@f-CNT powder is as follows: first, TPTP-COF reaction monomers and acidified carbon nanotubes f-CNTs are added to a reaction container, wherein the amount of acidified carbon nanotubes f-CNTs added is 5wt.% to 40wt.% of the total weight of the TPTP-COF reaction monomers; The TPTP-COF reaction monomers include 2,4,6-tris(4-aminophenyl)-1,3,5-triazine TPT-3NH2 and 2,4,6-tris(4-carboxyphenyl)-1,3,5-triazine TPT-3CHO. During the synthesis of the TPTP-COF@f-CNT powder, 2,4,6-tris(4-aminophenyl)-1,3,5-triazine TPT-3NH2 and 2,4,6-tris(4-carboxyphenyl)-1,3,5-triazine TPT-3CHO are added in equal moles. Then, 1-10 ml of 1,4-dioxane and 1-10 ml of trimethylbenzene were added, followed by 0.5-5 ml of acetic acid with a concentration of 3-9 mol / L. The reaction vessel was sealed and the gas was purged while maintaining the vacuum condition in the reaction vessel. The reaction vessel was heated to 120°C and reacted for 3 days. After the reaction was completed, the purified covalent organic framework / carbon nanotube composite material TPTP-COF@f-CNT was finally dried under vacuum to obtain TPTP-COF@f-CNT powder.

2. The nanocomposite film according to claim 1, wherein: The preparation process of the TPTP-COF@f-CNT powder is as follows: 0.15 mmol of 2,4,6-tris(4-aminophenyl)-1,3,5-triazine TPT-3NH2, 0.15 mmol of 2,4,6-tris(4-carboxyphenyl)-1,3,5-triazine TPT-3CHO, and 5.0 wt.% to 15.0 wt.% of the total weight of the TPTP-COF reaction monomers were added to a reaction bottle, and 5 ml of 1,4-dioxane and 5 ml of trimethylbenzene were added, followed by 1.2 ml of a 6 molar concentration of ethanol. mol / L acetic acid, and then the reaction bottle was sealed and the gas was purged while maintaining the vacuum inside the container. The reaction bottle was heated to 120°C for 3 days. After the reaction was completed, it was purified using tetrahydrofuran, acetone and methanol to collect the green solid covalent organic framework / carbon nanotube composite material TPTP-COF@f-CNT, which was then dried under vacuum to obtain TPTP-COF@f-CNT powder with a yield of 70%.

3. The nanocomposite film according to claim 1, wherein: The nanocomposite film was prepared by adding 3 g of PVDF-HFP powder to 12 mL of dimethylformamide and doping it with TPTP-COF@f-CNT powder to obtain a mixed solution. Before electrospinning, the mixed solution was subjected to ultrasonic vibration for 1 hour and stirred in an oil bath at 60°C until the mixed solution was completely dissolved to obtain a TPTP-COF@f-CNT / PVDF-HFP electrospinning solution. The TPTP-COF@f-CNT / PVDF-HFP electrospinning solution was placed in a 10 mL syringe, and nanofibers were collected using a roller. The TPTP-COF@f-CNT / PVDF-HFP electrospinning solution was pushed out using the syringe. The electrospinning operating parameters were set as follows: operating voltage 13-14 kV, flow rate: 1.4 ml / hr, metal roller speed: 1500 rpm, temperature: 27.5°C ± 2.5°C, and humidity 45 ± 5%. The electrospinning was continued for 4 hours. The nanofiber membrane was then collected and dried in a vacuum oven set at 60°C for 6 hrs to remove the DMF residue to obtain the TPTP-COF@ f-CNT / PVDF-HFP composite film.

4. The nanocomposite film according to claim 1, wherein: The addition amount of TPTP-COF@f-CNT is 0.5 wt%~2.0 wt.% of the total weight of PVDF-HFP powder.

5. The nanocomposite film according to claim 1, wherein: During the synthesis of the TPTP-COF@f-CNT powder, the amount of acidified carbon nanotubes (f-CNTs) added is 5.0 wt.%, 10.0 wt.%, or 15.0 wt.% of the total weight of the TPTP-COF reactive monomers; and the amount of TPTP-COF@f-CNTs added is 0.5 wt.%, 1.0 wt.%, 1.5 wt.%, or 2.0 wt.% of the total weight of the PVDF-HFP powder.

6. An electrostatic generator, characterized in that: It comprises a positive friction layer and a negative friction layer, wherein the negative friction layer comprises the nanocomposite film according to any one of claims 1 to 5, and the positive friction layer comprises a TPU layer, wherein the TPU layer adopts a thermoplastic polyurethane TPU nanofiber membrane.

7. The electrostatic generator according to claim 1, wherein: The preparation process of the thermoplastic polyurethane TPU nanofiber membrane is as follows: a certain amount of thermoplastic polyurethane TPU is added and dissolved in an organic solvent to form a TPU electrospinning solution, and the added amount of thermoplastic polyurethane TPU is 5.0-20.0 wt.% of the TPU electrospinning solution, and then the TPU electrospinning solution is spun to obtain the thermoplastic polyurethane TPU nanofiber membrane.

8. The electrostatic generator according to claim 7, characterized in that: The preparation process of the thermoplastic polyurethane (TPU) nanofiber membrane is as follows: 1.2 g of thermoplastic polyurethane is weighed and dissolved in 9.640 mL of a dimethylformamide / tetrahydrofuran (DMF) mixed solvent to form a TPU mixed solution, wherein the volume ratio of DMF to THF in the mixed solvent is 1:1; the TPU mixed solution is then placed in a 70°C oil bath and stirred for 12 hours until the TPU mixed solution is completely dissolved to form a TPU electrospinning solution; The TPU electrospinning solution was placed in a 10 mL syringe, and a roller was used to collect the nanofibers. The TPU electrospinning solution was pushed out through the syringe, and the electrospinning operating parameters were set as follows: operating voltage 11-12 kV, flow rate: 1.4 ml / hr, metal roller speed of 1500 rpm, temperature: 28.0 °C ± 2.5 °C and humidity 45 ± 5%. After electrospinning for 4 hrs, the nanofiber membrane was collected and placed in a vacuum oven set at 60 °C for 6 hrs to remove DMF / THF residues.

9. The electrostatic generator according to claim 7, characterized in that: The electrostatic generator is an electrostatic generator in a vertical contact separation mode. The positive friction layer also includes a first PP layer and a first conductive layer, and the first conductive layer is connected between the first PP layer and the TPU layer; the negative friction layer also includes a second PP layer and a second conductive layer, and the second conductive layer is connected between the second PP layer and the nano-composite film. The first PP layer and the second PP layer are spaced apart to form a sandwich. A spacer is provided between the first PP layer and the second PP layer. The nano-composite film and the TPU layer are arranged opposite to each other, and the two are respectively located in the sandwich.

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