A friction nanogenerator based on a silk fibroin / graphene composite film and a preparation method thereof

Abstract

The application relates to the field of nano new energy sources, and discloses a friction nanogenerator based on a silk fibroin / graphene composite film and a preparation method thereof. The preparation method of the silk fibroin / graphene composite film is simple, the silk fibroin film is obtained through multiple steps of shearing, degumming, dissolving and solution dialysis on natural silk, graphene is doped into the silk fibroin to enhance the output electric performance of the silk fibroin as a friction anode material. The friction nanogenerator is composed of friction materials and electrode materials, including the silk fibroin / graphene composite film, polytetrafluoroethylene and aluminum foil, adopts a vertical contact-separation working mode, and is assembled into an elastic structure to collect mechanical energy. The preparation method has low material cost, simple operation, good and stable output performance.

Description

Technical Field

[0001] This invention relates to the field of nanotechnology, and in particular to a triboelectric nanogenerator based on a silk fibroin / graphene composite film and its preparation method. Background Technology

[0002] Triboelectric nanogenerators were first proposed by Academician Wang Zhonglin in 2012. As a novel device for collecting nano-energy, they can collect various types of minute mechanical energy from the external environment and convert it into electrical energy, providing a self-powered and sustainable energy supply for micro- and nano-systems. This is an effective way to solve the drawbacks of traditional batteries, such as limited lifespan and the need for regular maintenance. The working principle of triboelectric nanogenerators is that when two materials with different surface tribopolarities approach each other, equal amounts of positive and negative charges are generated on the material surfaces based on the triboelectric effect. When the two materials separate, an induced potential difference is formed between the upper and lower electrodes, which then drives the flow of electrons through an external circuit.

[0003] Triboelectric materials are a crucial factor determining the performance of triboelectric nanogenerators. Currently, most materials used are organic polymers and similar materials, which often contain potentially harmful substances, are expensive, and have poor environmental sustainability and biocompatibility. Silk fibroin, a biodegradable material extracted from silkworms, not only possesses high flexibility, light transmittance, and stretchability but also exhibits strong electron-losing ability, occupying a prominent positive electrode position in the triboelectric sequence, making it an excellent candidate electrode material for preparing triboelectric nanogenerators. Furthermore, a key challenge for triboelectric nanogenerators as power systems is ensuring output performance while improving integration. Because the power output of triboelectric nanogenerators does not match the demands of external electronic devices, circuit conversion and long-term energy collection are required to maintain the operation of external devices, resulting in unstable power output and low conversion efficiency. Therefore, optimizing both triboelectric materials and device structure will provide modern society with a green, efficient, low-cost, and high-performance driving system, showing promising application prospects in the field of self-powered wearable electronic devices. Summary of the Invention

[0004] The purpose of this invention is to address the problems existing in the background technology by proposing a method for manufacturing a triboelectric nanogenerator based on silk fibroin / graphene composite film and polytetrafluoroethylene, which has a simple preparation process, low cost, and does not require high temperature and high pressure.

[0005] The technical solution of the present invention is a triboelectric nanogenerator based on a silk fibroin / graphene composite film, comprising a first friction material, a second friction material, a first electrode, and a second electrode, wherein the first electrode covers the back side of the first friction material; and the second electrode covers the back side of the second friction material.

[0006] The first friction material and the second friction material are stacked face to face, with a gap in the middle;

[0007] The first friction material is a silk fibroin / graphene composite film;

[0008] The second friction material is a polytetrafluoroethylene film;

[0009] Both the first and second electrodes are aluminum foil.

[0010] Preferably, a single-core multi-strand wire is connected between the first electrode and the first friction material, and between the second electrode and the second friction material.

[0011] Preferably, the surface of the polytetrafluoroethylene film used as the second friction material is polished to increase the surface roughness.

[0012] Preferably, the silk fibroin / graphene composite film is obtained by processing natural silk through multiple steps such as shearing, degumming, dissolving, and solution dialysis to form a silk fibroin solution, and then doping it with a redox graphene solution and drying it.

[0013] A method for preparing a triboelectric nanogenerator based on a silk fibroin / graphene composite film, comprising the following specific steps:

[0014] Step 10: Weigh the raw silk and anhydrous sodium carbonate using a balance, ensuring that the mass ratio of raw silk to anhydrous sodium carbonate is 2.358:1. Take 1L of deionized water for every 5g of raw silk, boil the deionized water and add anhydrous sodium carbonate. After the anhydrous sodium carbonate is fully dissolved, add the raw silk and keep boiling for 30 minutes to dissolve the sericin on the surface of the raw silk.

[0015] Step 20: Rub the degummed raw silk with deionized water several times to thoroughly remove the sericin from the surface of the raw silk. Wring out the degummed silk and let it air dry.

[0016] Step 30: Take 1.35g of degummed silk fibroin, soak it in 5mL of 9.3mol / L lithium bromide solution, place it in a 60℃ oven for 3 hours to dissolve and obtain silk fibroin protein solution, and dialyze it with deionized water at 0℃ for 2 hours.

[0017] Step 40: Measure 1 mL of a 2 mg / mL graphene (GO) solution into a beaker and sonicate it at 80 Hz for 1 hour in an ultrasonic shaker to uniformly disperse the GO nanosheets. Weigh 20 mg of ascorbic acid and dissolve it completely in 1 mL of deionized water. Add the dissolved ascorbic acid solution to the GO solution and stir until homogeneous.

[0018] Step 50: Add the mixed solution obtained in Step 40 to the silk fibroin solution prepared in Step 30; stir magnetically for 12 hours to ensure that the two solutions are fully mixed; add 300 μL of 1,4-butanediol diglycidyl ether (BDDE) to the mixed solution, and continue stirring for five minutes to ensure that the crosslinking agent BDDE and the solution are fully mixed; dry at 50°C for 1 hour to obtain a silk fibroin / graphene composite film.

[0019] Step 60: The obtained silk fibroin / graphene composite film and the polished polytetrafluoroethylene film are attached to aluminum foil and connected to single-core multi-strand wires to assemble a triboelectric nanogenerator.

[0020] Preferably, in step 30, preparing a lithium bromide solution with a concentration of 9.3 mol / L includes the following steps:

[0021] Step 31: Add 81.56g of lithium bromide powder to a beaker containing 50mL of deionized water;

[0022] Step 32: Place the magnetic rotor into the beaker, place the beaker on the magnetic stirrer, set the speed to 600 r / min, and stir until the solution is clear;

[0023] Step 33: After turning off the stirrer, let the solution stand at room temperature, and add water to 100 mL with a dropper to obtain a lithium bromide solution with a concentration of 9.3 mol / L.

[0024] Preferably, in step 60, aluminum foil is first pasted onto an acrylic plate and single-core multi-strand wires are led out, and then polytetrafluoroethylene tape is used to cover the surface of the aluminum foil; the silk fibroin / graphene composite film is made by uniformly coating the aluminum foil surface with a solution and then drying it.

[0025] Preferably, a polyimide (PI) film is added between the acrylic sheet and the aluminum foil, and the elasticity of the polyimide film enables the automatic separation of the silk fibroin / graphene composite film and polytetrafluoroethylene.

[0026] Compared with the prior art, the present invention has the following beneficial technical effects:

[0027] 1. This invention applies a silk fibroin / graphene composite film and polytetrafluoroethylene (PTFE) to the triboelectric material of a triboelectric nanogenerator. This material exhibits strong triboelectric negativity and high triboelectric efficiency, while being non-toxic, harmless, biocompatible, highly transparent, and possessing excellent tensile strength, meeting the requirements of wearable devices. The selected PTFE is high-strength, wear-resistant, and non-stick, and is located at the top of the triboelectric sequence with a negative charge. This overcomes the problems of water molecules within silk affecting triboelectric performance and high surface stickiness, improving its electrical performance output and providing more material options for the development of biocompatible triboelectric nanogenerators.

[0028] 2. This invention optimizes the materials of the triboelectric nanogenerator device, improves the power density of the triboelectric nanogenerator and stabilizes its output. It is low-cost, compact, and easy to carry, and has a wider range of applications. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of a triboelectric nanogenerator structure based on silk fibroin / graphene composite film and polytetrafluoroethylene according to the present invention.

[0030] Figure 2 This is a schematic diagram of the output voltage of a triboelectric nanogenerator based on silk fibroin / film and polytetrafluoroethylene according to the present invention;

[0031] Figure 3 This is a schematic diagram of the output voltage of a triboelectric nanogenerator based on silk fibroin / graphene composite film and polytetrafluoroethylene according to the present invention.

[0032] Figure 4 This is a schematic diagram of the surface and internal structure of the silk fibroin / graphene composite film of the present invention.

[0033] Reference numerals: 1. First electrode; 2. First friction material; 3. Second friction material; 4. Second electrode. Detailed Implementation

[0034] Example 1

[0035] This invention proposes a triboelectric nanogenerator based on a silk fibroin-graphene composite film, such as... Figure 1 As shown, it includes a first friction material 2, a second friction material 3, a first electrode 1, and a second electrode 4. The first electrode 1 covers the back of the first friction material 2, and the second electrode 4 covers the back of the second friction material 3.

[0036] The first friction material 2 and the second friction material 3 are stacked face to face, with a gap in the middle;

[0037] The first friction material 2 is a silk fibroin / graphene composite film;

[0038] The second friction material 3 is a polytetrafluoroethylene film;

[0039] Both the first electrode 1 and the second electrode 4 are aluminum foil.

[0040] In this configuration, a single-core multi-strand wire is connected between the first electrode 1 and the first friction material 2, and between the second electrode 4 and the second friction material 3.

[0041] Among them, the surface of the polytetrafluoroethylene film selected for the second friction material 3 is polished to increase the surface roughness.

[0042] The silk fibroin / graphene composite film is made by processing natural silk through multiple steps such as shearing, degumming, dissolving, and solution dialysis to form a silk fibroin solution, and then doping it with a redox graphene solution and drying it.

[0043] The two aluminum foils are connected to conductive leads and are fixed to the upper and lower substrates respectively. The two substrates are connected by a PI film, which is secured by the elastic deformation generated when the PI film is bent.

[0044] Example 2

[0045] The method for manufacturing the triboelectric nanogenerator of the silk fibroin / graphene composite film in this invention includes the following steps:

[0046] Step 10: Weigh the raw silk and anhydrous sodium carbonate using a balance, ensuring that the mass ratio of raw silk to anhydrous sodium carbonate is 2.358:1. Take 1L of deionized water for every 5g of raw silk, boil the deionized water and add anhydrous sodium carbonate. After the anhydrous sodium carbonate is fully dissolved, add the raw silk and keep boiling for 30 minutes to dissolve the sericin on the surface of the raw silk.

[0047] Step 20: Rub the degummed raw silk with deionized water several times to thoroughly remove the sericin from the surface of the raw silk. Wring out the degummed silk and let it air dry.

[0048] Step 30: Take 1.35g of degummed silk fibroin, soak it in 5mL of 9.3mol / L lithium bromide solution, place it in a 60℃ oven for 3 hours to dissolve and obtain silk fibroin protein solution, and dialyze it with deionized water at 0℃ for 2 hours.

[0049] Step 30, preparing a 9.3 mol / L lithium bromide solution, includes the following steps:

[0050] Step 31: Add 81.56g of lithium bromide powder to a beaker containing 50mL of deionized water;

[0051] Step 32: Place the magnetic rotor into the beaker, place the beaker on the magnetic stirrer, set the speed to 600 r / min, and stir until the solution is clear;

[0052] Step 33: After turning off the stirrer, let the solution stand at room temperature, and add water to 100 mL with a dropper to obtain a lithium bromide solution with a concentration of 9.3 mol / L;

[0053] Step 40: Measure 1 mL of a 2 mg / mL graphene (GO) solution into a beaker and sonicate it at 80 Hz for 1 hour in an ultrasonic shaker to uniformly disperse the GO nanosheets. Weigh 20 mg of ascorbic acid and dissolve it completely in 1 mL of deionized water. Add the dissolved ascorbic acid solution to the GO solution and stir until homogeneous.

[0054] Step 50: Add the mixed solution obtained in Step 40 to the silk fibroin solution prepared in Step 30; stir magnetically for 12 hours to ensure that the two solutions are fully mixed; add 300 μL of 1,4-butanediol diglycidyl ether (BDDE) to the mixed solution, and continue stirring for five minutes to ensure that the crosslinking agent BDDE and the solution are fully mixed; dry at 50°C for 1 hour to obtain a silk fibroin / graphene composite film.

[0055] Step 60: The obtained silk fibroin / graphene composite film and the polished polytetrafluoroethylene film are attached to aluminum foil and connected to single-core multi-strand wires to assemble a triboelectric nanogenerator.

[0056] The process involves first attaching aluminum foil to an acrylic board and then drawing out single-core multi-strand wires, followed by covering the aluminum foil surface with polytetrafluoroethylene tape. The silk fibroin / graphene composite film is made by uniformly coating a solution onto the aluminum foil surface and then drying it.

[0057] Preferably, a polyimide (PI) film is added between the acrylic sheet and the aluminum foil, and the elasticity of the polyimide film enables the automatic separation of the silk fibroin / graphene composite film and the polytetrafluoroethylene.

[0058] The aluminum foil in the aforementioned triboelectric nanogenerator based on silk fibroin / graphene composite film and polytetrafluoroethylene is led out and connected to a full-wave bridge rectifier circuit for rectification and output.

[0059] like Figure 2 , 3 As shown, a comparative experiment was conducted between the triboelectric nanogenerator based on silk fibroin / graphene composite film and polytetrafluoroethylene prepared using the method of the present invention and the existing triboelectric nanogenerator based on silk fibroin film and polytetrafluoroethylene. The triboelectric nanogenerator of the present invention has a higher output voltage.

[0060] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited thereto. Various changes can be made within the scope of knowledge possessed by those skilled in the art without departing from the spirit of the present invention.

Claims

1. A triboelectric nanogenerator based on a silk fibroin / graphene composite film, comprising a first friction material (2), a second friction material (3), a first electrode (1), and a second electrode (4), characterized in that: The first electrode (1) covers the back side of the first friction material (2); the second electrode (4) covers the back side of the second friction material (3); The first friction material (2) and the second friction material (3) are stacked face to face with a gap in the middle; The first friction material (2) is a silk fibroin / graphene composite film; The second friction material (3) is a polytetrafluoroethylene film; Both the first electrode (1) and the second electrode (4) are aluminum foils; Triboelectric nanogenerators are prepared according to the following steps: Step 10: Weigh the raw silk and anhydrous sodium carbonate using a balance, ensuring that the mass ratio of raw silk to anhydrous sodium carbonate is 2.358:

1. Take 1L of deionized water for every 5g of raw silk, boil the deionized water and add anhydrous sodium carbonate. After the anhydrous sodium carbonate is fully dissolved, add the raw silk and keep boiling for 30 minutes to dissolve the sericin on the surface of the raw silk. Step 20: Rub the degummed raw silk with deionized water several times to thoroughly remove the sericin from the surface of the raw silk. Wring out the degummed silk and let it air dry. Step 30: Take 1.35 g of degummed silk fibroin, soak it in 5 mL of 9.3 mol / L lithium bromide solution, place it in a 60 ℃ oven for 3 hours to dissolve and obtain silk fibroin protein solution, and dialyze it with deionized water at 0 ℃ for 2 hours. Step 40: Measure 1 mL of graphene GO solution with a concentration of 2 mg / mL into a beaker, and sonicate it at 80 Hz for 1 h in an ultrasonic oscillator to uniformly disperse the GO nanosheets; weigh 20 mg of ascorbic acid and dissolve it completely in 1 mL of deionized water; add the dissolved ascorbic acid solution to the GO solution and stir well. Step 50: Add the mixed solution obtained in Step 40 to the silk fibroin solution prepared in Step 30; stir magnetically for 12 hours to ensure that the two solutions are fully mixed; add 300 μL of 1,4-butanediol diglycidyl ether (BDDE) to the mixed solution, and continue stirring for five minutes to ensure that the crosslinking agent BDDE and the solution are fully mixed; dry at 50 °C for 1 hour to obtain a silk fibroin / graphene composite film. Step 60: The obtained silk fibroin / graphene composite film and the polished polytetrafluoroethylene film are attached to aluminum foil and connected to single-core multi-strand wires to assemble a triboelectric nanogenerator.

2. The triboelectric nanogenerator based on a silk fibroin / graphene composite film according to claim 1, characterized in that, Single-core multi-strand wires are connected between the first electrode (1) and the first friction material (2) and between the second electrode (4) and the second friction material (3).

3. The triboelectric nanogenerator based on a silk fibroin / graphene composite film according to claim 1, characterized in that, The surface of the polytetrafluoroethylene film selected for the second friction material (3) is polished to increase the surface roughness.

4. The triboelectric nanogenerator based on a silk fibroin / graphene composite film according to claim 1, characterized in that, The silk fibroin / graphene composite film is obtained by processing natural silk through multiple steps such as shearing, degumming, dissolving, and solution dialysis to form a silk fibroin solution, and then doping it with a redox graphene solution and drying it.

5. The triboelectric nanogenerator based on a silk fibroin / graphene composite film according to claim 1, characterized in that, Step 30, preparing a 9.3 mol / L lithium bromide solution, includes the following steps: Step 31: Add 81.56 g of lithium bromide powder to a beaker containing 50 mL of deionized water; Step 32: Place the magnetic rotor into the beaker, place the beaker on the magnetic stirrer, set the speed to 600 r / min, and stir until the solution is clear; Step 33: After turning off the stirrer, let the solution stand at room temperature, and add water to 100 mL with a dropper to obtain a lithium bromide solution with a concentration of 9.3 mol / L.

6. The triboelectric nanogenerator based on a silk fibroin / graphene composite film according to claim 1, characterized in that, In step 60, aluminum foil is first pasted onto an acrylic plate and single-core multi-strand wires are led out, and then polytetrafluoroethylene tape is used to cover the surface of the aluminum foil; the silk fibroin / graphene composite film is made by uniformly coating the aluminum foil surface with a solution and then drying it.

7. A triboelectric nanogenerator based on a silk fibroin / graphene composite film according to claim 6, characterized in that, A polyimide (PI) film is added between the acrylic sheet and the aluminum foil. The elasticity of the polyimide film enables the automatic separation of the silk fibroin / graphene composite film and polytetrafluoroethylene.

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