A method for preparing triboelectric nanogenerators using a regenerable fiber gel membrane as a negative triboelectric layer.

Abstract

This invention discloses a method for preparing triboelectric nanogenerators using a regenerable fiber gel membrane as a negative triboelectric layer. Under the action of hydrochloric acid, the amino groups in chitosan ionize, forming highly electron-donating amino cations, endowing the gel membrane with strong triboelectric negativity. Introducing a reinforcing phase into the gel membrane system improves the stability and surface roughness of the gel membrane network, thereby enhancing the performance of the triboelectric nanogenerator assembled using it as the negative triboelectric layer. This invention is simple to operate, low in cost, and the triboelectric nanogenerator assembled using the regenerable fiber gel membrane prepared by this invention as the negative triboelectric layer exhibits high open-circuit voltage and short-circuit current, good stability, and is biodegradable.

Description

Technical Field

[0001] This invention relates to the fields of natural polymers and triboelectric nanogenerators, and specifically to a method for preparing a triboelectric nanogenerator using a regenerable fiber gel membrane as a negative triboelectric layer. Background Technology

[0002] With the proliferation of portable electronic devices, trillions of sensors will be ubiquitous worldwide. The batteries powering these sensors require constant location, maintenance, and replacement, making battery-powered systems for this ever-growing sensor network extremely costly and impractical. In this context, harvesting energy from the sensor's environment to achieve self-powered sensing becomes a potential alternative. Triboelectric nanogenerators (TENGs), composed of two materials with different electronegativity, can harvest various forms of mechanical energy, such as human movement, vibration, wind, and flowing water. They then convert this mechanical energy into electrical energy based on the triboelectric effect and electrostatic induction. This clean, stable, and maintenance-free energy source makes them a potentially optimal alternative to batteries.

[0003] Initially, both triboelectric layers of TENGs were composed of synthetic polymer films. For example, polyamide (PA) and polyoxymethylene (POM) were typically used as positive triboelectric layers, while polydimethylsiloxane (PDMS) and polytetrafluoroethylene (PTFE) were typically used as negative triboelectric layers. Driven by environmental awareness, natural polymers such as cellulose and chitosan have been used for the positive triboelectric layers in TENGs. However, due to the limitations of the triboelectric properties of natural materials, the negative triboelectric layers in these TENGs are still composed of fluorine- or silicon-containing synthetic polymers. Their relatively low biocompatibility and degradability limit the application of TENGs in human health, safety, and communication. Therefore, how to formulate natural polymers into highly electronegative negative triboelectric layer materials to prepare degradable, all-biomass-based TENGs remains a pressing problem to be solved. Summary of the Invention

[0004] The purpose of this invention is to address the problems of poor biocompatibility, limited application, and difficult degradation of TENG (triboelectric nanogenerator) due to the reliance on synthetic polymers for the negative triboelectric layer. This invention provides a method for preparing triboelectric nanogenerators using a regenerable fiber gel membrane as the negative triboelectric layer. Under the action of hydrochloric acid, the amino groups in chitosan ionize to form highly electron-donating amino cations, endowing the gel membrane with strong triboelectric negative properties. By introducing a reinforcing phase into the gel membrane system, the stability and surface roughness of the gel membrane network are improved, thereby enhancing the performance of the triboelectric nanogenerator assembled with it as the negative triboelectric layer. To achieve the above objectives, the present invention adopts the following technical solution: A method for preparing a triboelectric nanogenerator using a regenerable fiber gel membrane as a negative triboelectric layer includes the following steps: (1) Chitosan is dissolved in a hydrochloric acid solution with a certain pH. While heating and stirring in a water bath, a crosslinking agent and a reinforcing phase are added to form a mixed solution. After reacting in a water bath for a certain time, the solution is molded and refrigerated to form a hydrogel film.

[0005] (2) The hydrogel membrane obtained in step (1) is immersed in an ethanol solution for solvent replacement. After further cross-linking through cyclic freeze-thaw cycles, a regenerable fiber gel membrane is formed. The gel membrane is then assembled with a metal electrode as a negative triboelectric layer to form a triboelectric nanogenerator.

[0006] Furthermore, the pH of the hydrochloric acid solution in step (1) is 0.5-2.

[0007] Further, in the mixed solution described in step (1), the mass fractions of chitosan, crosslinking agent, and reinforcing phase are 2-5 wt%, 0.5-2 wt%, and 0.5-2 wt%, respectively.

[0008] Furthermore, the water bath reaction temperature in step (1) is 40-80 ℃, and the water bath reaction time is 1-3 h.

[0009] Further, the crosslinking agent in step (1) is any one of humic acid, polydopamine, and cashew phenol.

[0010] Further, the reinforcing phase in step (1) is any one of bacterial cellulose, microcrystalline cellulose, or cellulose nanocrystals.

[0011] Furthermore, the volume concentration of the ethanol solution in step (2) is 50%-100%, and the solvent replacement time is 1-2 days.

[0012] Further, the metal electrode in step (2) is any one of copper electrode, aluminum electrode, or silver electrode.

[0013] Chitosan, as the only abundant amino-based polysaccharide in nature, possesses natural biodegradability and biocompatibility, making it a promising functional ingredient in wearable devices. This invention leverages the polyamino properties of chitosan by dissolving it in hydrochloric acid, ionizing the amino groups into highly electron-gathering amino cations. This imparts strong triboelectric negativity to the chitosan gel film. Furthermore, the triboelectric performance of the chitosan gel film is enhanced by introducing a reinforcing phase, enabling it to be used as a negative triboelectric layer in the assembly of triboelectric nanogenerators.

[0014] Significant advantages of this invention: (1) This invention uses biomass as the main raw material, which is low in cost, safe, and easy to produce. The prepared renewable fiber gel membrane has strong electron-acquiring ability, is biodegradable, and can be used as a negative triboelectric layer to assemble triboelectric nanogenerators.

[0015] (2) The triboelectric nanogenerator assembled in this invention avoids the use of synthetic polymer materials, has good biodegradability, high open-circuit voltage and short-circuit current, and good stability. Attached Figure Description

[0016] Figure 1 Open-circuit voltage diagram of a triboelectric nanogenerator assembled with a negative triboelectric layer using the regenerable fiber gel membrane prepared in this invention. Figure 2 Short-circuit current diagram of a triboelectric nanogenerator assembled with a negative triboelectric layer using the regenerable fiber gel membrane prepared in this invention; Figure 3 This is a scanning electron microscope image of the regenerable fiber gel membrane obtained in Example 3; Figure 4 This is a scanning electron microscope image of the regenerable fiber gel membrane obtained in Comparative Example 1. Detailed Implementation

[0017] To make the content of this invention easier to understand, the technical solutions of this invention will be further explained in conjunction with specific embodiments, but this invention is not limited thereto.

[0018] Example 1 Take 2 g of chitosan and add it to 50 mL of hydrochloric acid solution with pH 1. Stir to dissolve and obtain a chitosan solution. Under stirring conditions in a 60℃ water bath, add 1 g of humic acid and 0.5 g of bacterial cellulose to the chitosan solution and stir for 1 h to obtain a homogeneous mixed solution. Mold the mixed solution and refrigerate it. Immerse it in anhydrous ethanol solution for 1 day. After cyclic freeze-thaw cycles, a regenerable fiber gel membrane is formed. Assemble it with copper electrodes to form a triboelectric nanogenerator.

[0019] The triboelectric performance of the assembled triboelectric nanogenerator was tested using a pressure-controlled linear motor (R-LP4) and an electrometer (KEITHLEY 6514) under test pressure of 50 N and friction frequency of 3 Hz. The maximum open-circuit voltage of the triboelectric nanogenerator was 56.04 V and the maximum short-circuit current was 1.67 μA.

[0020] Example 2 1.5 g of chitosan was added to 50 mL of hydrochloric acid solution with pH 1 and stirred to dissolve, yielding a chitosan solution. Under stirring conditions in a 60℃ water bath, 0.5 g of cashew nut shell powder and 1 g of microcrystalline cellulose were added to the chitosan solution and stirred for 1 h to obtain a homogeneous mixture. The mixture was then molded and refrigerated, immersed in a 50% ethanol solution for 2 days, and after cyclic freeze-thaw cycles, a regenerable fiber gel membrane was formed. This membrane was then assembled with a silver electrode to form a triboelectric nanogenerator.

[0021] The triboelectric power generation performance of the assembled triboelectric nanogenerator was tested using a pressure-controlled linear motor (R-LP4) and an electrometer (KEITHLEY 6514) under test pressure of 50 N and friction frequency of 3 Hz. The maximum open-circuit voltage of the triboelectric nanogenerator was 57.11 V and the maximum short-circuit current was 1.64 μA.

[0022] Example 3 2 g of chitosan was added to 50 mL of hydrochloric acid solution with pH 1.5 and stirred to dissolve, obtaining a chitosan solution. Under stirring conditions in a 60℃ water bath, 0.5 g of polydopamine and 1 g of cellulose nanocrystals were added to the chitosan solution and stirred for 2 hours to obtain a homogeneous mixed solution. The mixed solution was molded and refrigerated, then immersed in a 75% ethanol solution for 1 day. After cyclic freeze-thaw cycles, a regenerable fiber gel membrane was formed, which was then assembled with an aluminum electrode to form a triboelectric nanogenerator.

[0023] The triboelectric power generation performance of the assembled triboelectric nanogenerator was tested using a pressure-controlled linear motor (R-LP4) and an electrometer (KEITHLEY 6514) under test pressure of 50 N and friction frequency of 3 Hz. The maximum open-circuit voltage of the triboelectric nanogenerator was 51.28 V and the maximum short-circuit current was 1.58 μA.

[0024] Comparative Example 1 Take 2 g of chitosan and add it to 50 mL of hydrochloric acid solution with pH 1.5. Stir in a water bath at 60 °C to obtain a chitosan solution. Mold the chitosan solution and freeze it to form a shape. Immerse it in a 75% ethanol solution for 1 day. After repeated freeze-thaw cycles, a regenerable fiber gel membrane is formed. Assemble the membrane with an aluminum electrode to form a triboelectric nanogenerator.

[0025] The triboelectric performance of the assembled triboelectric nanogenerator was tested using a pressure-controlled linear motor (R-LP4) and an electrometer (KEITHLEY 6514) under test pressure of 50 N and friction frequency of 3 Hz. The maximum open-circuit voltage of the triboelectric nanogenerator was 32.42 V and the maximum short-circuit current was 1.13 μA.

[0026] The maximum open-circuit voltage of the triboelectric nanogenerator assembled from the regenerable fiber gel membrane prepared in the example ( Figure 1 ) and maximum short-circuit current ( Figure 2 The ratio was significantly higher than that of the comparative example. In the examples, chitosan, under the action of the crosslinking agent, formed a denser gel film network with the reinforcing phase, increasing the density of amino cations per unit area of ​​the gel film. Furthermore, the presence of the micro / nano-scale reinforcing phase in the gel film increased the surface roughness of the gel film. Figure 3This increases the contact area between the triboelectric layer and the positive triboelectric layer, thus generating a larger potential difference between the two triboelectric layers, thereby improving the triboelectric power generation performance of the triboelectric nanogenerator. In contrast to the example, the comparative pure chitosan gel membrane has a loose structure, a lower density of amino cations per unit area, and a smooth surface. Figure 4 The contact area between the triboelectric nanogenerator and the positive triboelectric layer is small, resulting in poor triboelectric power generation performance.

[0027] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made within the scope of the claims of the present invention should be included in the scope of the present invention.

Claims

1. A method for preparing a triboelectric nanogenerator using a regenerable fiber gel membrane as a negative triboelectric layer, characterized in that: Includes the following steps: (1) Chitosan is dissolved in hydrochloric acid solution. While heating and stirring in a water bath, a crosslinking agent and a reinforcing phase are added to form a mixed solution. After the reaction in a water bath, the solution is molded and refrigerated to form a hydrogel film. (2) The hydrogel membrane obtained in step (1) is immersed in an ethanol solution for solvent replacement, and after repeated freeze-thaw cycles, it is further cross-linked to form a regenerable fiber gel membrane, which is then assembled with a metal electrode as a negative triboelectric layer to form a triboelectric nanogenerator. The pH of the hydrochloric acid solution in step (1) is 0.5-2; In step (1), the mass fractions of chitosan, crosslinking agent, and reinforcing phase in the mixed solution are 2-5 wt%, 0.5-2 wt%, and 0.5-2 wt%, respectively. The crosslinking agent mentioned in step (1) is any one of humic acid, polydopamine, and cashew phenol; The reinforcing phase mentioned in step (1) is any one of bacterial cellulose, microcrystalline cellulose, or cellulose nanocrystals.

2. The method for preparing a triboelectric nanogenerator using a regenerable fiber gel membrane as a negative triboelectric layer as described in claim 1, characterized in that: The temperature of the water bath reaction in step (1) is 40-80 ℃, and the reaction time is 1-3 h.

3. The method for preparing a triboelectric nanogenerator using a regenerable fiber gel membrane as a negative triboelectric layer as described in claim 1, characterized in that: The volume concentration of the ethanol solution in step (2) is 50%-100%, and the solvent replacement time is 1-2 days.

4. The method for preparing a triboelectric nanogenerator using a regenerable fiber gel membrane as a negative triboelectric layer as described in claim 1, characterized in that: The metal electrode mentioned in step (2) is any one of copper electrode, aluminum electrode, or silver electrode.

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