Microcrystalline cellulose triboelectric composite film, preparation method thereof and triboelectric nano-generator

Abstract

The invention belongs to the technical field of friction power generation, and particularly relates to a microcrystalline cellulose triboelectric composite film, a preparation method thereof and a triboelectric nano-generator. Comprising the following steps: adding soluble trivalent iron salt into microcrystalline cellulose dispersion liquid, uniformly dispersing, and adding polyethyleneimine in a stirring state to form a dispersion system; adjusting the pH value of the dispersion system, adding a cross-linking agent for activation to obtain a mixture, carrying out a cross-linking reaction to cross-link microcrystalline cellulose and a liquid amine derivative, complexing with ferric ions to obtain a composite film precursor, and drying the composite film precursor to obtain the microcrystalline cellulose triboelectric composite film. According to the invention, microcrystalline cellulose is taken as a matrix, polyethyleneimine and microcrystalline cellulose are crosslinked and complexed with Fe < 3 + >, and a recyclable, biodegradable and biocompatible composite film is constructed, so that the triboelectricity output and humidity adaptability of the cellulose-based triboelectricity material are improved, and the energy efficiency of the material in a self-powered process in a high-humidity environment is enhanced.

Description

Technical Field

[0001] The present invention belongs to the technical field of triboelectric generation, and in particular relates to a microcrystalline cellulose triboelectric composite film, a preparation method thereof, and a triboelectric nanogenerator. Background Art

[0002] With the development of industries such as the Internet of Things and smart homes, flexible wearable sensors have attracted widespread attention in a variety of fields, including artificial intelligence devices, medical monitoring, soft robotics, electronic skin, and human-machine interfaces. However, their widespread application is often limited by their dependence on external power sources and the complexity of their manufacturing processes. In 2012, Academician Wang Zhonglin developed a device that converts mechanical energy into electrical energy: a triboelectric nanogenerator (TENG). This innovation has attracted widespread attention because it can achieve the shared goals of developing self-powered sensors and simplifying manufacturing processes. The core of a TENG is its triboelectric material. Currently, the triboelectrically positive materials used in TENGs are primarily petroleum-based and synthetic polymers, such as polyamide (PA) and polyethylene terephthalate (PET). These are non-renewable and non-biodegradable, posing a threat to human health and the environment. Furthermore, in high humidity environments, the large amount of water molecules in the air can affect the surface charge density generated by the triboelectric material, leading to the transfer, neutralization, and dissipation of the surface charge, significantly reducing output performance. Therefore, the development of renewable and biodegradable triboelectrically positive materials is a key challenge facing TENGs.

[0003] Cellulose is a sustainable green resource that is renewable, biodegradable, biocompatible, and cost-effective. Its molecular chain consists of hundreds of d-pyranose glucose rings interconnected by β-1,4-glycosidic bonds, and its surface is rich in oxygen atoms with lone electron pairs. Therefore, cellulose is a promising environmentally friendly triboelectric material. However, cellulose has an almost neutral relative polarity, which is slightly positive in the triboelectric series. Its ability to generate surface charge is limited. Furthermore, due to its high hydrophilicity, cellulose is prone to overhydration in high humidity environments. The electrostatic shielding effect of water molecules on the cellulose surface leads to charge dissipation and a decrease in power output, which severely reduces the output performance of cellulose-based TENGs and limits their further practical applications.

[0004] Cellulose is rich in hydroxyl groups, and its surface polarity can be enhanced through chemical modification, physical mixing with other triboelectric materials, or doping with dielectric / piezoelectric / ferroelectric materials. Triboelectric properties can also be enhanced by introducing micro- / nanomorphology on the surface to increase the contact area between two triboelectric materials or by creating a highly porous network to enhance surface electrostatic charge formation. For example, Zhang et al. (Anti-moisture, anti-bacterial cellularulosictriboelectric materials enabled by hydroxyl coordination effect. DOI: 10.1016 / j.nanoen.2024.109472) used cellulose nanofibers (CNFs) as a matrix and fabricated a Cu(II)-based TENG (Teng) thin film. The resulting CNF-Cu(II) thin film maintained high electrical output even in a high humidity environment (90% RH). Pan et al. (Hydrophobic sisal cellulose paper-based TENG for collecting rain energy and raindrop-based sensor. DOI: 10.1016 / j.cej.2024.151590) modified the surface of sisal cellulose paper by physically adsorbing polymers and chemically grafting monomers to prepare hydrophobic sisal cellulose paper (SCP) as a friction layer, and assembled the hydrophobic SCP into SCP-TENG to collect water droplet energy.

[0005] The above-mentioned method still faces the problems of sensitivity to over-hydration in high humidity environment, poor structural stability, high charge dissipation, which in turn leads to reduced triboelectric performance, high preparation cost, single function, and difficulty in large-scale production. Summary of the Invention

[0006] In order to solve the above problems, the present invention provides a microcrystalline cellulose triboelectric composite film, a preparation method thereof, and a triboelectric nanogenerator to improve the triboelectric output and humidity adaptability of cellulose-based triboelectric materials and enhance the energy efficiency of the material's self-powered process in a high humidity environment.

[0007] The present invention solves the above technical problems through the following technical solutions.

[0008] The first object of the present invention is to provide a method for preparing a microcrystalline cellulose triboelectric composite film, comprising the following steps: S1. Add soluble trivalent iron salt to the microcrystalline cellulose dispersion, disperse evenly, and then add polyethyleneimine under stirring to form a dispersion system.

[0009] S2. Adjust the pH of the dispersion system to 12-13 and add a cross-linking agent to obtain a mixture, subject the mixture to a cross-linking reaction at 45°C-60°C to cross-link the microcrystalline cellulose and the liquid amine derivative and complex them with trivalent iron ions to obtain a composite film precursor, and dry the composite film precursor to obtain a microcrystalline cellulose triboelectric composite film.

[0010] Furthermore, in the dispersed system, the amount of soluble trivalent iron salt is 5wt%~25wt% of the mass of microcrystalline cellulose, the amount of liquid amine derivative is 20wt%~80wt% of the mass of microcrystalline cellulose, and the soluble trivalent iron salt is ferric chloride hexahydrate.

[0011] Furthermore, the liquid amine derivative is monoethanolamine, diethanolamine, triethanolamine, 3-amino-1-propanol, ethylenediamine, triethylamine, diethylenetriamine, triethylenetetramine, morpholine, polyethyleneimine, soluble polyetheramine or polyethyleneamine.

[0012] Furthermore, the mass concentration of the microcrystalline cellulose dispersion is 13 wt % to 15 wt %.

[0013] Furthermore, the amount of the cross-linking agent used is 1.5 mmol / g to 1.8 mmol / g of the microcrystalline cellulose, the solvent used to adjust the pH is NaOH solution, and the concentration of the NaOH solution is 0.5 mol / L to 0.6 mol / L.

[0014] Furthermore, the cross-linking agent is ethylene glycol diglycidyl ether or polyethylene glycol diglycidyl ether.

[0015] Furthermore, the cross-linking reaction time is 0.5 h to 2 h.

[0016] Furthermore, before drying, the composite film precursor is fumigated with a water-soluble alcohol or water-soluble ketone organic solvent for 4 to 6 hours.

[0017] Furthermore, the water-miscible low surface energy polar organic solvent is methanol, anhydrous ethanol, acetone, or isopropanol.

[0018] The second object of the present invention is to provide a microcrystalline cellulose triboelectric composite film prepared by the above-mentioned preparation method.

[0019] The third object of the present invention is to provide a triboelectric nanogenerator, which is prepared by using the above-mentioned microcrystalline cellulose triboelectric composite film as the positive electrode material and the polytetrafluoroethylene film as the negative electrode material.

[0020] Compared with the prior art, the present invention has the following beneficial effects: The present invention provides a method for preparing a triboelectric microcrystalline cellulose composite film. The method uses microcrystalline cellulose as a matrix and introduces an amino-rich amine compound. Under weak alkaline conditions, microcrystalline cellulose (MCC) swells to expose additional hydroxyl groups. The amino functional groups on the amine compound and the hydroxyl groups on the MCC form a strong electrostatic interaction. The covalent crosslinking is carried out by a crosslinking agent, and the hydroxyl groups of the microcrystalline cellulose and the Fe 3+ Complexation, Fe 3+ The complexation with MCC and amine compounds induces lattice distortion through interchain spacing expansion, thereby reducing structural order and overall crystallinity. At the molecular level, a multi-crosslinked network structure composed of covalent crosslinking, ionic complexation, and hydrogen bonding is formed, improving the stability of the composite film and reducing crystallinity. By combining MCC modification with micromorphological adjustment of the composite film, the present invention obtains an MCC-based composite film with high triboelectric output and high humidity adaptability, forming a recyclable, biodegradable, and biocompatible composite film. Due to the synergistic effect of the multi-network structure and micromorphology, the electrical output performance of the TENG based on the MCC composite film is greatly improved, and it exhibits excellent humidity adaptability and fatigue resistance. It also introduces adjustable mechanical flexibility, overcoming the inherent brittleness limitation of natural cellulose-based materials. This TENG has broad application prospects in pressure and humidity sensing, energy harvesting, and intelligent identification.

[0021] The preparation process of the present invention is simple and can be completed using existing simple conventional equipment without the need for special equipment. The prepared microcrystalline cellulose triboelectric composite film has excellent mechanical properties, wet stability, recyclability and degradability, and is low in cost, green and has good biocompatibility.

[0022] In order to further improve the performance of microcrystalline cellulose triboelectric composite film, the present invention uses a water-miscible low surface energy polar organic solvent to fumigate the composite film precursor, inducing interfacial molecular exchange between the water-miscible low surface energy polar organic solvent and bound water in the membrane matrix, accelerating the dehydration dynamics (accelerating film drying) and reducing the interfacial energy, thereby promoting the self-organization of the hierarchical microstructure and constructing a rich micromorphology at the microscopic level. The higher triboelectric performance of TENG is improved through the synergistic effect of the combination of multi-cross-linked structure and microstructure refinement induced by fumigation with water-soluble alcohols or water-soluble ketones organic solvents and thickness optimization. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The embodiments of the present invention have different PEI concentrations and different Fe 3+ Scanning electron microscope images of the composite film surface with different concentrations.

[0024] Figure 2 MP is an embodiment of the present invention. 60 F20 and f-MP 60 F 20 Surface and cross-sectional microstructure diagrams, Figure 2 a in the table is MP 60 F 20 Cross-section microstructure, b is MP 60 F 20 N element distribution diagram of the cross section, c is MP 60 F 20 Fe element distribution diagram of the cross section, d is MP 60 F 20 Surface atomic force microscopy image, a1 is f-MP 60 F 20 Cross-sectional microstructure, b1 is f-MP 60 F 20 N element distribution diagram of the cross section, c1 is f-MP 60 F 20 Fe element distribution diagram of the cross section, d1 is f-MP 60 F 20 Surface AFM.

[0025] Figure 3 The embodiments of the present invention have different PEI concentrations and different Fe 3+ Graph of the hydrophobic properties of composite films with different concentrations.

[0026] Figure 4 The present invention has different PEI dosages and different Fe 3+ Comparison of the output voltage of TENG based on microcrystalline cellulose triboelectric composite film under different dosages. Figure 4 a represents different PEI dosages, b represents different Fe 3+ dose.

[0027] Figure 5 The present invention is based on MP 60 F 20 and f-MP 60 F 20 The output voltage comparison chart of TENG, Figure 5 a in the table is MP 60 F 20 and f-MP 60 F 20 Output voltage comparison diagram, b is f-MP 60 F 20 Output current, c is f-MP 60 F 20 of transferred charge.

[0028] Figure 6 The present invention is based on f-MP 60 F 20The output voltage diagram of TENG in the frequency range of 1Hz to 20Hz, Figure 6 Where a is the frequency range of 1Hz to 5Hz, b is the frequency range of 6Hz to 15Hz, and c is the linear relationship of the frequency range.

[0029] Figure 7 The present invention is based on f-MP 60 F 20 TENG pressure sensing performance diagram, Figure 7 a is the output voltage at different contact areas, b is the output voltage of TENG under different applied forces, c is the relationship between open-circuit voltage and applied force and the linear fitting curve, d is the pressure response and recovery under 5 Hz and 15 N working conditions, and e is the output voltage after 42,000 working cycles.

[0030] Figure 8 The present invention is based on f-MP 60 F 20 The capacitor charging curve of TENG, Figure 8 a is the charging curve of capacitors with different capacitances, b is the output voltage, current density, and output power density of TENG under variable load resistance, c is a photo of the LED lamp power supply, and d is the operating voltage curve of the thermometer and hygrometer.

[0031] Figure 9 The present invention is based on f-MP 60 F 20 Humidity adaptability and humidity-sensitive properties of thin film TENG, Figure 9 a is based on MP under different humidity conditions 60 F 20 The output voltage of TENG is shown in Fig. 2, b is the output voltage of TENG based on MP under different humidity conditions. 60 F 20 The output current of TENG, c is the linear fitting relationship between the output voltage of TENG and humidity.

[0032] Figure 10 The present invention is based on f-MP 60 F 20 Voltage retention of thin film TENG in high humidity environment compared with other studies.

[0033] Figure 11 The present invention is based on MP under different humidity conditions 60 F 20 Comparison of the output voltage of TENG of thin film and commercial printing paper, Figure 11 (a) Based on MP under different humidity conditions 60 F 20(b) is the output voltage of TENG assembled with commercial printing paper and polytetrafluoroethylene film as positive and negative friction layers under different humidity conditions.

[0034] Figure 12 The present invention is based on f-MP 60 F 20 Changes in the output voltage of the thin-film TENG after immersion in water.

[0035] Figure 13 The present invention is based on f-MP 60 F 20 Output voltage diagram of the thin film TENG under 98% RH, 15N and 5 Hz conditions.

[0036] Figure 14 The f-MP-based 60 F 20 Output voltage diagram of TENG.

[0037] Figure 15 The present invention is based on f-MP 60 F 20 Application of thin film TENG Schematic diagram of TENG device and electronic output signal in different parts of the body, Figure 15 (a) shows finger flexion, wrist rotation, neck tilt, elbow flexion, and knee movement, and (b) shows the transition from walking to running and jumping.

[0038] Figure 16 The present invention is based on f-MP 60 F 20 Schematic diagram of the TENG device and electronic output signal during nasal and oral breathing. Figure 16 In the middle, a represents nasal and oral breathing, and b represents continuous coughing.

[0039] Figure 17 The present invention is based on f-MP 60 F 20 、f-MP 60 F 20 ON and f-MP 60 F 20 -60d film output voltage at 5Hz and 15N conditions.

[0040] Figure 18 The present invention is under the conditions of 5Hz and 15N, f-MP 60 F 20 Output voltage, output current, transferred charge and biocompatibility diagram of ON-60d membrane, Figure 18Where a is the output voltage, b is the output current, c is the transferred charge, and d is the biocompatibility diagram.

[0041] Figure 19 MP of the present invention 60 F0, f-MP 60 F 20 and MP 70 Diagram of the degradation process of F5 membrane. DETAILED DESCRIPTION

[0042] The following will provide a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0043] It should be noted that the professional terms used in the present invention are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention. Unless otherwise specified, the various raw materials, reagents, instruments and equipment used in the following embodiments of the present invention can be purchased from the market or prepared by existing methods.

[0044] Existing researchers have made great efforts to improve the humidity adaptability and electrical output performance of cellulose-based TENGs, but they still face the problems of sensitivity to overhydration in high humidity environments, resulting in poor structural stability, charge dissipation, and reduced triboelectric performance. In addition, the preparation cost is high, the function is single, and it is difficult to mass-produce. Therefore, exploring a simple, economical, environmentally friendly, and efficient method to enhance the triboelectric output of cellulose molecules and improve their adaptability to harsh environments such as high humidity is a very promising and urgent task.

[0045] Based on this, the present invention provides a method for preparing a microcrystalline cellulose triboelectric composite film, comprising the following steps: S1. Add soluble trivalent iron salt to the microcrystalline cellulose dispersion, disperse evenly, and then add polyethyleneimine under stirring to form a dispersion system.

[0046] S2. Adjust the pH of the dispersion system to 12-13 and add a cross-linking agent for activation to obtain a mixture, subject the mixture to a cross-linking reaction at 45°C-60°C to cross-link the microcrystalline cellulose and the liquid amine derivative and complex with trivalent iron ions to obtain a composite film precursor, and dry the composite film precursor to obtain a microcrystalline cellulose triboelectric composite film.

[0047] The present invention uses microcrystalline cellulose as a matrix and introduces a liquid amine derivative rich in amino groups. Under weak alkaline conditions, microcrystalline cellulose (MCC) swells to expose additional hydroxyl groups. The amino functional groups on the liquid amine derivative and the hydroxyl groups on the MCC form a strong electrostatic interaction, which is covalently cross-linked by a cross-linking agent. The hydroxyl groups of the microcrystalline cellulose and Fe 3+ Complexation, Fe 3+ The complexation with MCC and liquid amine derivatives induces lattice distortion through interchain spacing expansion, thereby reducing structural order and overall crystallinity. This results in a multi-crosslinked network structure of covalent crosslinking, ionic complexation, and hydrogen bonding at the molecular level, improving the stability of the composite film and reducing crystallinity. By combining MCC modification with micromorphological adjustment of the composite film, the present invention obtains an MCC-based composite film with high triboelectric output and high humidity adaptability, forming a recyclable, biodegradable, and biocompatible composite film. Due to the synergistic effect of the multi-network structure and micromorphology, the electrical output performance of the TENG based on the MCC composite film is greatly improved, and it exhibits excellent humidity adaptability and fatigue resistance. It also introduces adjustable mechanical flexibility, overcoming the inherent brittleness limitation of natural cellulose-based materials. This TENG has broad application prospects in pressure and humidity sensing, energy harvesting, and intelligent identification.

[0048] In some embodiments, in the dispersed system, the amount of soluble ferric salt is 5 wt% to 25 wt% of the mass of the microcrystalline cellulose, the amount of the liquid amine derivative is 20 wt% to 80 wt% of the mass of the microcrystalline cellulose, and the soluble ferric salt is ferric chloride hexahydrate.

[0049] In some embodiments, the liquid amine derivative is monoethanolamine, diethanolamine, triethanolamine, 3-amino-1-propanol, ethylenediamine, triethylamine, diethylenetriamine, triethylenetetramine, morpholine, polyethyleneimine, a soluble polyetheramine, or polyvinylamine. It should be noted that the liquid amine derivatives used in the present invention include, but are not limited to, monoethanolamine, diethanolamine, triethanolamine, 3-amino-1-propanol, ethylenediamine, triethylamine, diethylenetriamine, triethylenetetramine, morpholine, polyethyleneimine, a soluble polyetheramine, or polyvinylamine. As long as the liquid amine derivative is rich in amino reactive groups and forms a strong electrostatic interaction with the hydroxyl groups on the MCC, it can be used.

[0050] In some embodiments, the mass concentration of the microcrystalline cellulose dispersion is 13 wt % to 15 wt %.The microcrystalline cellulose dispersion is an aqueous dispersion, and water is added to the microcrystalline cellulose and magnetically stirred at room temperature to obtain the microcrystalline cellulose dispersion.

[0051] In some embodiments, the amount of the cross-linking agent used is 1.5 mmol / g to 1.8 mmol / g of the microcrystalline cellulose, the solvent used to adjust the pH is NaOH solution, and the concentration of the NaOH solution is 0.5 mol / L to 0.6 mol / L.

[0052] It should be noted that under alkaline conditions, the concentration of hydroxide ions in the reaction system is relatively high, which is conducive to accelerating the rate of the ring-opening reaction, shortening the time required for activation, and improving the reaction efficiency.

[0053] In some embodiments, the cross-linking agent is ethylene glycol diglycidyl ether or polyethylene glycol diglycidyl ether.

[0054] It should be noted that the crosslinking agent used in the present invention is a glycidyl ether compound. The cellulose molecular chain contains numerous hydroxyl groups (-OH). Under alkaline conditions, the epoxy groups in the glycidyl ether compound undergo a ring-opening addition reaction with the hydroxyl groups on the cellulose molecules. The epoxy groups in the glycidyl ether compound also react with the amino groups in the PEI. The nitrogen atom on the amino group has a lone pair of electrons, exhibiting nucleophilicity and attacking the carbon atom on the epoxy ring, causing the epoxy ring to open. After ring opening, the nitrogen atom forms a new chemical bond with the carbon atom in the epoxy group, generating a secondary or tertiary amine structure. This achieves crosslinking between the cellulose and PEI.

[0055] In some embodiments, the purpose of activation is to improve reaction efficiency. As a preferred embodiment of the present invention, the activation time is 15 min to 20 min.

[0056] In some embodiments, the cross-linking reaction time is 0.5 h to 2 h.

[0057] In some embodiments, the composite film precursor is further fumigated with a water-soluble alcohol or water-soluble ketone organic solvent for 4 to 6 hours before drying. It should be noted that to further improve the performance of the microcrystalline cellulose triboelectric composite film, the present invention uses a water-soluble alcohol or water-soluble ketone organic solvent, such as anhydrous ethanol, to fumigate the composite film precursor. This induces interfacial molecular exchange between ethanol and bound water within the film matrix, accelerates dehydration kinetics (accelerates film drying), and simultaneously reduces interfacial energy, thereby promoting the self-organization of the hierarchical microstructure and constructing a rich micromorphology at the microscopic level. The synergistic effect of the multi-crosslinked structure and the microstructural refinement and thickness optimization induced by ethanol fumigation enhances the high triboelectric performance of the TENG.

[0058] The second object of the present invention is to provide a microcrystalline cellulose triboelectric composite film prepared by the above-mentioned preparation method. It should be noted that the microcrystalline cellulose triboelectric composite film provided by the present invention has a multi-crosslinked network and a hierarchical microstructure, forming a multi-network structure including covalent crosslinking, hydrogen bonding and ionic interaction within the composite matrix. This structural integration reduces the surface active sites of water interaction, while regulating the crystallization domain and jointly suppressing hydrophilicity. At the same time, the synergistic crosslinking between ions, MCC and PEI increases the charge center distance, induces electron delocalization and enhances the dipole moment, thereby further improving the triboelectric output.

[0059] A third objective of the present invention is to provide a triboelectric nanogenerator, fabricated using the aforementioned microcrystalline cellulose triboelectric composite film as the negative electrode material and a polytetrafluoroethylene film as the positive electrode material. The method for preparing the triboelectric nanogenerator comprises the following steps: providing back electrodes on both the negative and positive electrode materials; then affixing the negative and positive electrode materials to substrates, separating the two back electrodes with a sponge and connecting them to a circuit via copper wire, thereby assembling the triboelectric nanogenerator in a vertical contact-separation mode.

[0060] The following is further described through specific examples.

[0061] Example 1 A method for preparing a microcrystalline cellulose triboelectric composite film comprises the following steps: S1. Deionized water was added to 1 g of microcrystalline cellulose (MCC), and the mixture was magnetically stirred at room temperature for 10 min to obtain a microcrystalline cellulose dispersion. The mass fraction of microcrystalline cellulose in the microcrystalline cellulose dispersion was 14 wt%.

[0062] S2. Add ferric chloride hexahydrate (FeCl3·6H2O) to the crystalline cellulose dispersion. The amount of FeCl3·6H2O is 20 wt% of the mass of the microcrystalline cellulose. Stir for 12 h until the dispersion is uniform. Then, add polyethyleneimine (PEI) under continuous stirring. The amount of PEI is 20 wt% of the mass of the microcrystalline cellulose. Stir for 2 h to form a dispersion system.

[0063] S3. Add 1.5 mL of 0.5 mol / L NaOH aqueous solution to the dispersed system, adjust the pH to 12, and then add polyethylene glycol diglycidyl ether (PEGDE) in an amount of 1.5 mmol / g of microcrystalline cellulose. Activate at room temperature for 20 minutes to obtain a mixture.

[0064] S4. The mixture was cross-linked at 50°C for 1.5 h in a water bath to obtain a composite film precursor solution, which was poured into a silicon dioxide film mold with a length × width × height of 8 cm × 8 cm × 1 cm. The solution was dried in a vacuum drying oven at 50°C for 1.5 h to obtain a microcrystalline cellulose triboelectric composite film named MP 60 F 20 .

[0065] Example 2 A method for preparing a microcrystalline cellulose triboelectric composite film is different from the preparation method of Example 1 in that: the amount of FeCl3·6H2O in S2 is 5wt% of the mass of the microcrystalline cellulose, and the amount of PEI is 20wt% of the mass of the microcrystalline cellulose.

[0066] The obtained microcrystalline cellulose triboelectric composite film was named MP 20 F5.

[0067] Example 3 A method for preparing a microcrystalline cellulose triboelectric composite film is different from the preparation method of Example 1 in that: the amount of FeCl3·6H2O in S2 is 5wt% of the mass of the microcrystalline cellulose, and the amount of PEI is 30wt% of the mass of the microcrystalline cellulose.

[0068] The obtained microcrystalline cellulose triboelectric composite film was named MP 30 F5.

[0069] Example 4 A method for preparing a microcrystalline cellulose triboelectric composite film is different from the preparation method of Example 1 in that: the amount of FeCl3·6H2O in S2 is 5wt% of the mass of the microcrystalline cellulose, and the amount of PEI is 40wt% of the mass of the microcrystalline cellulose.

[0070] The obtained microcrystalline cellulose triboelectric composite film was named MP 40 F5.

[0071] Example 5 A method for preparing a microcrystalline cellulose triboelectric composite film is different from the preparation method of Example 1 in that: the amount of FeCl3·6H2O in S2 is 5wt% of the mass of the microcrystalline cellulose, and the amount of PEI is 50wt% of the mass of the microcrystalline cellulose.

[0072] The obtained microcrystalline cellulose triboelectric composite film was named MP 50 F5.

[0073] Example 6 A method for preparing a microcrystalline cellulose triboelectric composite film is different from the preparation method of Example 1 in that: the amount of FeCl3·6H2O in S2 is 5wt% of the mass of the microcrystalline cellulose, and the amount of PEI is 60wt% of the mass of the microcrystalline cellulose.

[0074] The obtained microcrystalline cellulose triboelectric composite film was named MP 60 F5.

[0075] Example 7 A method for preparing a microcrystalline cellulose triboelectric composite film is different from the preparation method of Example 1 in that: the amount of FeCl3·6H2O in S2 is 5wt% of the mass of the microcrystalline cellulose, and the amount of PEI is 70wt% of the mass of the microcrystalline cellulose.

[0076] The obtained microcrystalline cellulose triboelectric composite film was named MP 70 F5.

[0077] Example 8 A method for preparing a microcrystalline cellulose triboelectric composite film is different from the preparation method of Example 1 in that: the amount of FeCl3·6H2O in S2 is 5wt% of the mass of the microcrystalline cellulose, and the amount of PEI is 80wt% of the mass of the microcrystalline cellulose.

[0078] The obtained microcrystalline cellulose triboelectric composite film was named MP 80 F5.

[0079] Example 9 A method for preparing a microcrystalline cellulose triboelectric composite film is different from the preparation method of Example 1 in that: the amount of FeCl3·6H2O in S2 is 5wt% of the mass of the microcrystalline cellulose, and the amount of PEI is 60wt% of the mass of the microcrystalline cellulose.

[0080] The obtained microcrystalline cellulose triboelectric composite film was named MP 60 F5.

[0081] Example 9 A method for preparing a microcrystalline cellulose triboelectric composite film is different from the preparation method of Example 1 in that: the amount of FeCl3·6H2O in S2 is 10wt% of the mass of the microcrystalline cellulose, and the amount of PEI is 60wt% of the mass of the microcrystalline cellulose.

[0082] The obtained microcrystalline cellulose triboelectric composite film was named MP 60 F 10 .

[0083] Example 10 A method for preparing a microcrystalline cellulose triboelectric composite film is different from the preparation method of Example 1 in that: the amount of FeCl3·6H2O in S2 is 15wt% of the mass of the microcrystalline cellulose, and the amount of PEI is 60wt% of the mass of the microcrystalline cellulose.

[0084] The obtained microcrystalline cellulose triboelectric composite film was named MP 60 F 15 .

[0085] Example 11 A method for preparing a microcrystalline cellulose triboelectric composite film is different from the preparation method of Example 1 in that: the amount of FeCl3·6H2O in S2 is 25wt% of the mass of the microcrystalline cellulose, and the amount of PEI is 60wt% of the mass of the microcrystalline cellulose.

[0086] The obtained microcrystalline cellulose triboelectric composite film was named MP 60 F 25 .

[0087] Example 12 A method for preparing a microcrystalline cellulose triboelectric composite film is different from the preparation method of Example 1 in that: in S4, the obtained microcrystalline cellulose triboelectric composite film is fumigated with anhydrous ethanol for 4 hours and then completely dried in a 60° C. oven for 5 hours.

[0088] The obtained microcrystalline cellulose triboelectric composite film was named f-MP 60 F 20 .

[0089] Comparative Example 1 A method for preparing a microcrystalline cellulose triboelectric composite film, which differs from the preparation method of Example 1 in that: PEI is not added in S2.

[0090] The obtained microcrystalline cellulose triboelectric composite film was named MP 60 F0.

[0091] Comparative Example 2 A method for preparing a microcrystalline cellulose triboelectric composite material, which differs from the preparation method of Example 1 in that: FeCl3·6H2O is not added to S2.

[0092] The obtained microcrystalline cellulose triboelectric composite material is named MP0F 20 .

[0093] The structures of the microcrystalline cellulose triboelectric composite films prepared in Examples 1 to 12 and Comparative Examples 1 and 2 were tested. The results are as follows:

[0094] Figure 1 The embodiments of the present invention have different PEI concentrations and different Fe 3+ The surface scanning electron microscope image of the composite film with different concentrations. Figure 1 As shown, the low PEI content (MP 20 F5 and MP 30 F5), the membrane exhibited a relatively smooth surface with minimal pores and pits, indicating a favorable compatibility between PEI and MCC. However, at PEI content ≥ 40 wt%, the surface roughness increased significantly, accompanied by the formation of a lamellar structure and local pits. 60 F0) shows a relatively flat morphology with many microcracks, and after the addition of FeCl3, the surface cracking is alleviated or eliminated.

[0095] Figure 2 MP is an embodiment of the present invention. 60 F 20 and f-MP 60 F 20 Surface and cross-sectional microstructure diagrams, Figure 2 a in the table is MP 60 F 20 Cross-section microstructure, b is MP 60 F 20 N element distribution diagram of the cross section, c is MP 60 F 20 Fe element distribution diagram of the cross section, d is MP 60 F 20 Surface AFM, a1 is f-MP 60 F 20 Cross-sectional microstructure, b1 is f-MP 60 F 20 N element distribution diagram of the cross section, c1 is f-MP 60 F 20 Fe element distribution diagram of the cross section, d is f-MP 60 F 20 Surface atomic force microscopy image. Figure 2 As shown, MP 60 F 20 The film exhibits significant roughness enhancement with abundant flake and block surface structures. 60 F 20 Energy dispersive X-ray spectroscopy confirmed that the Fe 3+The uniform distribution on the surface and cross section, comparative analysis shows that compared with MP60F20, the relative nitrogen content of f-MP60F20 is slightly higher on the surface and the iron content of the cross section is slightly higher. In addition, the quantitative analysis of atomic force microscopy images shows that f-MP 60 F 20 The arithmetic mean roughness (Ra) of (Ra=44nm) is better than that of MP 60 F 20 (Ra = 19.2 nm) increased by 2.3 times, confirming the enhancement of surface texture during fumigation.

[0096] Figure 3 The embodiments of the present invention have different PEI concentrations and different Fe 3+ The hydrophobic characteristics of the composite film with different concentrations. Figure 3 As shown, except for MP 80 Except for the F5 composite film, all composite films showed hydrophobic properties with water contact angles (WCA) exceeding 90°. 80 The F5 membrane showed moderate hydrophilicity (WCA: 85.4°). 3+ With the increase of MP content, the hydrophobicity showed a slight downward trend, but it was not significant. Ethanol fumigation slightly enhanced the surface hydrophilicity, but did not significantly improve it. This behavior is attributed to the formation of a multi-network structure including covalent cross-linking, hydrogen bonding and ionic interactions within the composite matrix. This structural integration reduces the surface active sites for water interaction and modulates the crystalline domains, which together suppresses hydrophilicity. 80 The exception of F5 is caused by the excessive PEI content, in which the abundant amine groups promote hydrogen bonding with water molecules, partially offsetting the cross-linking-induced hydrophobicity. These results confirm that the low hydrophilicity of the composite film is the result of the synergistic effect of the multimodal cross-linking mechanism.

[0097] A triboelectric nanogenerator (TENG) is fabricated using a microcrystalline cellulose triboelectric composite film and a commercial polytetrafluoroethylene film as the triboelectric positive and negative electrode materials, respectively. Two copper sheets are attached to one side of the two triboelectric layer materials as back electrodes, and then each is fixed to a 1mm thick acrylic plate. The two electrodes are separated by an ethylene-vinyl acetate copolymer sponge and connected to a circuit via copper wire, thereby assembling a triboelectric nanogenerator in a vertical contact-separation mode, namely, a TENG. The composite film and commercial PTFE membrane serve as the triboelectric positive and negative layers, respectively.

[0098] Figure 4 The present invention has different PEI dosages and different Fe 3+ Comparison of the output voltage of TENG based on microcrystalline cellulose triboelectric composite film under different dosages. Figure 4 a represents different PEI dosages, b represents different Fe 3+ Dosage. Figure 4 As shown in (a), the output voltage of TENG exhibits a non-monotonic dependence on PEI concentration, initially increasing before decreasing. 60 The TENG of F5 showed the best performance, achieving a peak output voltage of 73.6V; Figure 4 As shown in b, the significant Fe 3+ Concentration-dependent enhancement, based on MP 60 F 20 The device achieved a significant output voltage of 125V, which is higher than its FeCl3-free counterpart based on MP 60 F0’s TENG) increased by 190%.

[0099] Figure 5 The present invention is based on MP 60 F 20 and f-MP 60 F 20 Comparison of the electrical output performance of TENG, Figure 5 a in the table is MP 60 F 20 and f-MP 60 F 20 Output voltage comparison diagram, b is f-MP 60 F 20 Output current, c is f-MP 60 F 20 The transferred charge. Figure 5 As shown, based on f-MP 60 F 20 The TENG showed good performance indicators: output current of 5.3μA, transfer charge of 32nC, output voltage of 248.3V, which is better than that of MP-based 60 F 20 The TENG increased by 198%. Notably, an asymmetric current signal distribution was observed, characterized by smaller amplitude variations during the separation process compared to the contact process, despite a prolonged duration. This phenomenon is attributed to the operating mechanism of the mechanical vibrator, which provides a fast pulsed contact force while relying on a restoring spring force for slower separation dynamics.

[0100] In summary, the introduction of PEI, which is rich in electron-donating amine groups, enhances the polarity of MCC by providing additional electrons during triboelectrification. However, excessive PEI loading increases the crystallinity of MCC, which promotes the embedding of -OH groups and hinders electron transport. 3+The introduction of ions effectively reduces the crystallinity while amplifying the interfacial polarization effect. These ions cooperate with the molecular chains to establish stable charge migration pathways to promote enhanced electron and ion transport. Precise ion dosage adjustment enables structural optimization of the multi-crosslinked network, especially through hydrogen bond reconstruction, which produces new polar domains to regulate spatial charge distribution and alleviate friction-induced performance degradation caused by excessive hydrogen bonding. At the same time, the synergistic crosslinking between ions, MCC and PEI increases the charge center distance, inducing electron delocalization and dipole moment enhancement, thereby further improving the triboelectric output. SEM analysis shows that the incorporation of MP into TENG 50 F5, MP 60 F5, and MP 60 F 20 The membrane exhibits amplified surface roughness, enlarged effective contact area and electrostatic induction sites during contact-separation cycles. Comparison of atomic force microscopy and scanning electron microscopy characterizations shows that f-MP 60 F 20 The film has a high surface roughness (R a =44nm, and MP 60 F 20 R a The f-MP has a 2D structure (19.2 nm) with prominent protrusions and depressions, transforming the 2D interfacial contact into a 3D interaction, significantly enhancing the active charge transfer region. Notably, increased triboelectric thickness adversely affects output performance due to electrostatic edge effects—larger electrode-material separation distances reduce the induced charge at equivalent triboelectric charge density. During operation, the transferred charge diffuses and accumulates within the triboelectric material until saturation is reached, limited by the counteracting electric field. 60 F 20 The reduction in film thickness optimizes this charge confinement, contributing to its superior triboelectric performance. Therefore, the higher triboelectric performance of this TENG comes from the synergistic effect of the multi-crosslinked structure of the film and the microstructural refinement induced by ethanol fumigation combined with thickness optimization.

[0101] The output voltage of TENG is closely related to the operating frequency, effective contact area and external pressure. Figure 6 The present invention is based on f-MP 60 F 20 The output voltage diagram of TENG in the frequency range of 1Hz to 20Hz, Figure 6 Where a is the frequency range of 1Hz to 5Hz, b is the frequency range of 6Hz to 15Hz, and c is the linear relationship of the frequency range. Figure 6 As shown, the TENG based on f-MP60F20 film shows a linear increase in output voltage (7.26 V / Hz, R 2=0.98). Edge voltage enhancement was observed at 6 Hz–12 Hz, where increasing frequency significantly impacted performance. However, further increasing the frequency to 15 Hz resulted in a significant voltage decrease, which was attributed to the accumulated microstructural damage under high-frequency mechanical fatigue. This frequency-dependent behavior arises from two competing mechanisms: (1) enhanced electrostatic charge accumulation and interfacial potential difference at moderate frequencies, which amplify the triboelectric output; and (2) excessive cyclic stress at ultrahigh frequencies, which compromises the integrity of the composite film.

[0102] Figure 7 The present invention is based on f-MP 60 F 20 TENG pressure sensing performance diagram, Figure 7 a is the output voltage at different contact areas, b is the output voltage of TENG at different applied forces, c is the relationship between open circuit voltage and applied force and the linear fitting curve, d is the pressure response and recovery at 5 Hz and 15 N, and e is the output voltage at 42,000 working cycles. Figure 7 As shown in a, f-MP 60 F 20 The effective contact area between the membrane and the PTFE film is expanded from 2cm×2cm to 5×5cm, and the output voltage can be increased by 10.61 times (23.4V→248.3V), which is proportional to the density of mobile free charges. Figure 7 As shown in Figures b and c, pressure dependence studies revealed a linear correlation between the applied force (5-15 N) and the peak voltage (214.5 V → 248.3 V), yielding a sensitivity of 3.136 V / N, highlighting the potential of this device for high-performance pressure sensing. Figure 7 As shown in Figure d, the TENG also exhibits fast dynamic responsiveness, with separation and contact response times of 60ms and 34ms, respectively, under 5N external pressure and 5Hz operation conditions, enabling real-time monitoring of transient mechanical stimulation. It is worth noting that the prolonged voltage signal duration during the separation phase compared to the contact process is consistent with the previously observed asymmetry of the current signal. This phenomenon can be alleviated by structural modifications, such as arched electrode configuration, which warrants further investigation. In addition, as Figure 7 As shown in (e), the output voltage remains stable over 42,000 consecutive vertical contact separation cycles with no obvious drop observed, demonstrating the excellent fatigue resistance of TENG.

[0103] TENG-based composite thin films have great potential for energy harvesting and self-powered applications. Mechanical energy harvested by the TENG is converted into electrical energy and subsequently rectified into direct current (DC) by a bridge rectifier. Six capacitors with varying capacitances were evaluated using a charging circuit consisting of a rectifier, commercial capacitors, and the TENG. Figure 8The present invention is based on f-MP 60 F 20 The capacitor charging curve of TENG, Figure 8 a is the charging curve of capacitors with different capacitances, b is the output voltage, current density and output power density of TENG under variable load resistance, c is a photo of the LED light power supply, and d is the working voltage curve of the thermometer and hygrometer. Figure 8 As shown in Figure a, the charging rate is negatively correlated with the capacitance. The 0.22μF capacitor reaches 120.5V in 32s, and the 10μF capacitor reaches 18.4V in 150s. 4 -10 9 Ω) to systematically characterize the output voltage, power density (P=U2 / (RS), where U, R and S are the output voltage, external resistance and contact area of the triboelectrodes respectively) and current density. Figure 8 As shown in Figure b, the output voltage first increases and then decreases with the increase of resistance, while the current density shows a downward trend. The power density optimization shows that the maximum value is 575.3mW / m at 20MΩ. 2 .like Figure 8 As shown in Figure c, TENG is integrated with light-emitting diodes (LEDs) through a rectifier bridge, and 500 LEDs (3V / light) can be lit simultaneously during operation. Figure 8 As shown in (d), the thermohygrometer can be powered by charging the capacitor (48 μF) for 1 minute by tapping the TENG.

[0104] In order to evaluate the humidity adaptability of TENG based on composite film, 5 cm × 5 cm 1MP 60 F 20 Film and f-MP of Example 12 60 F 20 The film is used as the positive friction layer assembly device material and the PTFE membrane is used as the negative friction layer counterpart.

[0105] Figure 9 The present invention is based on f-MP 60 F 20 Humidity adaptability and humidity-sensitive properties of thin film TENG, Figure 9 a is based on MP under different humidity conditions 60 F 20 The output voltage of TENG is shown in Fig. 2, b is the output voltage of TENG based on MP under different humidity conditions. 60 F 20 The output current of TENG is , and c is the linear fitting relationship between the output voltage of TENG and humidity. Figure 9As shown in Figure a, when the relative humidity increases from 20% to 80%, the output voltage increases from 243.1V to 273.2V, and the output current increases from 3.57μA to 4.51μA. Figure 9 As shown in Figure b, when the relative humidity further increases to 98%, the output voltage and output current drop to 240.4V and 3.45μA respectively. Further increase to 98%RH results in a decrease to 204.3V and 2.64μA. Figure 9 As shown in c, the fitting analysis shows that in the range of 20%RH to 80%RH and 80%RH to 98%RH, the humidity sensitivity is 0.49V / %RH (R 2 =0.97) and 3.8V / %RH (R 2 =0.98), indicating excellent humidity sensing performance under high humidity conditions.

[0106] Figure 10 The present invention is based on f-MP 60 F 20 Voltage retention of thin film TENG in high humidity environment compared with other studies. Figure 10Among them, 1 is the existing technology Biocompatible polydopamine based triboelectric nanogenerator for humidity sensing. DOI: 10.1016 / j.snb.2023.134384; 2 is the existing technology Synergistic energy harvesting and humidity sensing with single electrode triboelectric nanogenerator. DOI: 10.1016 / j.ceramint.2024.07.110; 3 is the existing technology Cellulose template-based triboelectric nanogenerators for self-poweredsensing at high humidity. DOI: 10.1016 / j.nanoen.2023.108196; 4 is the existing technology Asymmetric permittivity enhanced bilayer polycaprolactone nanofiber with superior inner interfacial polarization and charge retention for high-output and humidity-resistant triboelectric nanogenerators. DOI: 10.1016 / j.nanoen.2022.107289; 5 is the prior art Self-powered humidity sensor driven by triboelectric nanogenerator composed of bio-wasted peanut skin powder. DOI: 10.3390 / polym16060790; 6 is the prior art Flexible, humidity- and contamination-resistant superhydrophobic MXene-based electrospun triboelectric nanogenerators for distributed energy harvesting applications. DOI: 10.1039 / d3nr04537d, 7 is the present invention. Figure 10As shown in the results, the TENG of the present invention exhibits strong humidity adaptability in the entire range of 20%RH~98%RH, and outperforms many humidity-sensitive triboelectric materials in terms of sensitivity and voltage retention at high humidity (80%RH~98%RH).

[0107] In order to study the effect of PTFE on the humidity adaptability of TENG, a control device was fabricated using commercial printing paper and PTFE film as the positive and negative triboelectric layers, respectively. Figure 11 The present invention is based on MP under different humidity conditions 60 F 20 Comparison of the output voltage of TENG of thin film and commercial printing paper, Figure 11 (a) Based on MP under different humidity conditions 60 F 20 (b) is the output voltage of TENG assembled with commercial printing paper and polytetrafluoroethylene film as positive and negative friction layers under different humidity conditions. Figure 11 As shown in Figure 2, voltage output tests under the same conditions (20% RH to 85% RH) show that the performance is significantly reduced compared to the TENG based on the composite film. Although the output voltage of the control device increases slightly in the range of 20% RH to 60% RH, it drops sharply above 60% RH, reaching only 1.12 V at 85% RH.

[0108] In addition, despite the MP-based 60 F 20 TENG and f-MP-based 60 F 20 The TENG shows a similar trend in the output voltage variation with humidity, but is different from its f-MP 60 F 20 Compared with its counterparts, MP-based 60 F 20 The TENG exhibited significantly lower output voltage under the same humidity conditions. This higher performance stems from the multi-crosslinked network and hierarchical microstructure of the composite film, which synergistically enhance the triboelectric output. The humidity-adaptive behavior is determined by the dynamic balance between hydrogen-bonded water (facilitating charge transfer) and free water (inducing charge dissipation). At low humidity (20% RH to 80% RH), adsorbed water molecules form a gas-liquid interface layer, mitigating charge loss from free water. However, above 80% RH, excessive free water adsorption dominates, amplifying the electrostatic shielding effect and reducing the output.

[0109] Figure 12 The present invention is based on f-MP 60 F 20 The change of output voltage of thin film TENG after being immersed in water. Figure 12As shown in Figure 3, when immersed in water for 2 min, the TENG exhibited no detectable output voltage signal. However, upon removal, the device generated approximately 40 V within 1 s, and the voltage gradually increased to 120 V over the following 3 min.

[0110] Figure 13 The present invention is based on f-MP 60 F 20 The output voltage of the thin film TENG under 98% RH, 15N and 5 Hz conditions. Figure 13 As shown, the TENG exhibits excellent stability and durability under high humidity conditions. At 98% RH, it maintains a stable output voltage of 204 V over 21,000 consecutive contact separation cycles with minimal waveform distortion.

[0111] Figure 14 The f-MP-based 60 F 20 The output voltage diagram of TENG. Figure 14 As shown, long-term exposure tests in a sealed chamber at 98% RH showed no significant performance degradation, with the triboelectric voltage output remaining stable at 200 V after 1, 2, 3, 5, 8, and 11 days of continuous exposure. Notably, even after 11 days, the output voltage fluctuation was negligible, confirming the excellent durability in extreme humidity environments. These results highlight the potential application of TENG in environments prone to rain or high humidity.

[0112] In order to better simulate the f-MP 60 F 20 The actual operating conditions of thin film TENG, 5cm 2 ×5cm 2 With triboelectric electrodes attached to the skin of adult volunteers, the TENG exhibited a voltage increment proportional to the applied pressure during finger flexion, wrist rotation, neck tilt, elbow bending, and knee movements. Figure 15 The present invention is based on f-MP 60 F 20 Application of thin film TENG Schematic diagram of TENG device and electronic output signal in different parts of the body, Figure 15 Figure a represents finger flexion, wrist rotation, neck tilt, elbow flexion, and knee movement, and figure b represents the transition from walking to running and jumping. Figure 15 As shown, the TENG exhibited a voltage increment proportional to the applied pressure during finger flexion, wrist rotation, neck tilt, elbow bending, and knee movement. When the volunteers transitioned from walking to running and jumping, the voltage increased from 16.8 V to 25.9 V and 34.6 V, respectively, demonstrating its ability to accurately and reliably monitor limb movement and changes in motion state.

[0113] This invention demonstrates the effectiveness of real-time respiratory monitoring (including breathing and coughing) for health assessment. Figure 16 The present invention is based on f-MP 60 F 20 Schematic diagram of the TENG device and electronic output signal during nasal and oral breathing. Figure 16 In the figure, a refers to nasal and oral breathing, and b refers to continuous coughing. Figure 16 As shown in Figure a, comparative measurements of humidity and airflow velocity during the two breathing modes reveal different characteristics: nasal breathing occurs at a relative humidity of 89.5% and an airflow velocity of 1.3 m / s, while oral breathing is associated with elevated relative humidity (91.6%) and is accompanied by a significantly higher airflow velocity of 2.6 m / s. Although oral breathing occurs in an environment with higher relative humidity, its enhanced airflow velocity exerts a stronger mechanical stimulus on the TENG sensor, ultimately resulting in the output voltage being affected by the combined influence of ambient humidity and external mechanical force. Figure 16 As shown in middle b, the sensor can also reliably distinguish between coughing and mouth breathing. Compared with normal breathing signals, the rapid air expulsion during coughing produces a sharp voltage spike with a significantly steeper slope, thus enabling accurate event differentiation.

[0114] f-MP disassembled from the tested TENG 60 F 20 The membrane was cut into pieces, mixed with deionized water, and homogenized by high-speed shear dispersion. Subsequently, 50% of the freshly prepared MP 60 F 20 The membrane-forming solution is added to the mixture, thoroughly blended, and cast into a regenerated membrane. Ethanol fumigation and drying produce the recovered f-MP 60 F 20 ON membrane. The f-MP previously integrated into the TENG 60 F 20 The membranes were aged for 60 days under ambient room conditions to obtain f-MP 60 F 20 -60d film.

[0115] Figure 17 The present invention is based on f-MP 60 F 20 、f-MP 60 F 20 ON and f-MP 60 F 20 -60d film output voltage under 5Hz and 15N conditions. Figure 17 As shown, the output voltage is 227.8V (f-MP 60 F 20O-NTENG-based) and 248.3V (f-MP 60 F 20 -60d-based TENG).

[0116] Figure 18 The present invention is under the conditions of 5Hz and 15N, f-MP 60 F 20O-N -60d membrane output voltage, output current and transfer charge and biocompatibility diagram, Figure 18 Where a is the output voltage, b is the output current, c is the transferred charge, and d is the biocompatibility diagram. Figure 18 As shown in a to c, the f-MP aged for 60 days 60 F 20O-N membrane (designated as f-MP 60 F 20O-N -60d) was assembled into a triboelectric nanogenerator (TENG), which showed output parameters of 239.6 V, 4.2 μA, and 32 nC. 60 F 20 Compared with TENG, f-MP 60 F 20 -60d devices showed only a slight degradation in triboelectric performance. These findings validate the feasibility of reusing composite films by mixing aged and fresh materials, highlighting their superior durability for sustainable applications. Figure 18 To assess biocompatibility, the composite film was attached to actively growing holly leaves to monitor growth and color change (see middle d). One month after attachment, the leaves continued to show normal growth while retaining their green coloration. After three months, slight yellowing was observed, primarily at the edges of the adhesive, while the central area showed no significant color change, indicating minimal biological impact of the composite film.

[0117] Figure 19 MP of the present invention 60 F0, f-MP 60 F 20 and MP 70 The degradation process of F5 membrane is shown in the figure. Figure 19 As shown, by 60 F0, f-MP 60 F 20 and MP 70 F5 membrane samples were buried in outdoor soil to evaluate biodegradability. Residual mass measured after six months was 32%, 23%, and 25%, demonstrating significant degradation and confirming its excellent biodegradability.

[0118] It should be noted that when numerical ranges are mentioned in the present invention, it should be understood that both endpoints of each numerical range and any value between the two endpoints may be selected. Since the steps and methods used are the same as those in the embodiments, in order to avoid redundancy, the present invention describes preferred embodiments. Although preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they understand the basic inventive concepts. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0119] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

Claims

1. A method for preparing a microcrystalline cellulose triboelectric composite film, characterized in that: The following steps are involved: Adding soluble trivalent iron salt to the microcrystalline cellulose dispersion, and adding polyethyleneimine while stirring after uniform dispersion to form a dispersion system; The pH of the dispersion system is adjusted to 12-13 and a cross-linking agent is added to obtain a mixture. The mixture is subjected to a cross-linking reaction at 45°C-60°C to cross-link the microcrystalline cellulose and the liquid amine derivative and complex with trivalent iron ions to obtain a composite film precursor. The composite film precursor is dried to obtain a microcrystalline cellulose triboelectric composite film.

2. The method for preparing the microcrystalline cellulose triboelectric composite film according to claim 1, characterized in that: In the dispersed system, the amount of the soluble trivalent iron salt is 5wt% to 25wt% of the mass of the microcrystalline cellulose, the amount of the liquid amine derivative is 20wt% to 80wt% of the mass of the microcrystalline cellulose, and the soluble trivalent iron salt is ferric chloride hexahydrate.

3. The method for preparing the microcrystalline cellulose triboelectric composite film according to claim 1, wherein the liquid The amine derivative is monoethanolamine, diethanolamine, triethanolamine, 3-amino-1-propanol, ethylenediamine, triethylamine, diethylenetriamine, triethylenetetramine, morpholine, polyethyleneimine, a soluble polyetheramine or polyvinylamine.

4. The method for preparing a microcrystalline cellulose triboelectric composite film according to claim 1, characterized in that: The mass concentration of the microcrystalline cellulose dispersion is 13wt% to 15wt%.

5. The method for preparing the microcrystalline cellulose triboelectric composite film according to claim 1, characterized in that: The dosage of the cross-linking agent is 1.5 mmol / g to 1.8 mmol / g of the microcrystalline cellulose, the solvent used to adjust the pH is NaOH solution, and the concentration of the NaOH solution is 0.5 mol / L to 0.6 mol / L.

6. The method for preparing a microcrystalline cellulose triboelectric composite film according to claim 1, characterized in that: The cross-linking agent is ethylene glycol diglycidyl ether or polyethylene glycol diglycidyl ether.

7. The method for preparing a microcrystalline cellulose triboelectric composite film according to claim 1, characterized in that: The cross-linking reaction time is 0.5h to 2h.

8. The method for preparing a microcrystalline cellulose triboelectric composite film according to claim 1, characterized in that: Before drying, the composite film precursor is fumigated with a water-soluble alcohol or water-soluble ketone organic solvent for 4 hours.

9. A microcrystalline cellulose triboelectric composite film, characterized in that: The preparation method according to any one of claims 1 to 9 is used to prepare the compound.

10. A triboelectric nanogenerator, characterized in that: The triboelectric composite film of microcrystalline cellulose as claimed in claim 9 is used as the positive electrode material and the polytetrafluoroethylene film is used as the negative electrode material.

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