Hydroxyethyl cellulose-aramid / mxene nanometer friction positive electrode material and preparation method thereof

Abstract

The application relates to the field of friction nanogeneration, micro-nano energy collection and film material manufacturing, and particularly relates to a hydroxyethyl cellulose-aramid / MXene nano-friction positive electrode material and a preparation method thereof. The positive electrode material has a sandwich structure, a composite film formed by aramid nanofibers (ANF) and MXene through vacuum filtration is used as an inner layer, and the composite film combines the high strength and high modulus of aramid and the high conductivity of MXene. Hydroxyethyl cellulose of an outer layer is a protective layer and enhances the structural strength of the material, protects MXene from oxidation, improves the stability and durability of the material, is a contact friction layer, and the rich hydroxyl functional groups on the surface of the contact friction layer are beneficial to the easy transfer of electric charges, the generation of friction voltage, the provision of good electrostatic coupling induction and friction power generation capacity, and the provision of a new thought for the development of friction nanogeneration technology and a more efficient and environment-friendly solution for the application in the fields of flexible wearing, self-powered equipment and micro-nano energy collection.

Description

Technical Field

[0001] This invention relates to the fields of triboelectric nanogenerators, micro-nano energy harvesting, and membrane material manufacturing, specifically to a hydroxyethyl cellulose-aramid / MXene nano-triboelectric cathode material and its preparation method. Background Technology

[0002] With the rapid development of wearable devices, the Internet of Things (IoT), and portable electronic products, traditional battery power supply methods are no longer sufficient to meet the requirements of these devices in terms of portability, battery life, and environmental friendliness. Triboelectric nanogenerators (TENGs), as an emerging energy harvesting technology, are micro-nano energy supply systems that utilize triboelectric charging and electrostatic coupling effects to convert minute amounts of mechanical energy into electrical energy. They possess outstanding advantages in terms of high efficiency, sustainability, and environmental friendliness. The core of TENGs lies in the selection and design of their positive and negative triboelectric materials. These materials must possess excellent charge retention capabilities, good mechanical properties, and environmental stability to ensure efficient energy conversion and long-term operational reliability.

[0003] Para-aramid fibers, due to their ordered arrangement of amide bonds and the interactions between hydrogen bonds and π-π bonds in the molecular chains, possess high strength, high modulus, and good thermal and chemical stability, making them an ideal material for triboelectric power generation. However, pure aramid fibers have low surface polarity, and their smooth surface leads to weak triboelectric contact with other materials. Furthermore, the lack of conductive pathways on the surface often results in problems such as low surface binding energy, low charge density, and poor charge transfer efficiency and stability, limiting their practical application in triboelectric generation (TENG).

[0004] On the other hand, MXene, as a novel two-dimensional material, shows great potential in the field of energy storage and conversion. Its unique layered structure, composed of alternating layers of metal atoms and carbon / nitrogen atoms, and its excellent conductivity enable it to provide efficient charge transport during energy storage and conversion. MXene can improve the charge transfer efficiency of triboelectric materials, but its high surface activity makes it prone to aggregation, and its structural stability during long-term friction needs to be improved.

[0005] Hydroxyethyl cellulose (HEC), a water-soluble polymer, contains polar groups such as hydroxyl (-OH) and ethoxy (-OCH2CH2). These polar groups give HEC molecules strong hydrophilicity and polarity, good film-forming properties, lubrication and protective effects, and good charge transfer capabilities. In the preparation of triboelectric materials, HEC can serve as an effective coating material, not only enhancing the mechanical strength of composite materials but also improving their surface properties and charge retention capacity. Summary of the Invention

[0006] To address the shortcomings of traditional materials in terms of mechanical strength, friction performance, and charge retention, this invention provides a hydroxyethyl cellulose-aramid / MXene nano-triboelectric cathode material and its preparation method.

[0007] This invention is achieved through the following technical solution:

[0008] A hydroxyethyl cellulose-aramid / MXene nano-triboelectric cathode material is disclosed. The cathode material has a sandwich structure, with an inner layer of aramid / MXene vacuum-filtered composite film and an outer layer of hydroxyethyl cellulose protective layer.

[0009] A method for preparing a hydroxyethyl cellulose-aramid / MXene nano-triboelectric cathode material includes the following steps:

[0010] Step 1: Prepare hydroxyethyl cellulose dispersion, aramid nanofiber dispersion and MXene dispersion;

[0011] Step 2: After uniformly mixing the aramid nanofiber dispersion and the MXene dispersion, an ANF / MXene composite membrane is prepared by vacuum filtration and a first drying process.

[0012] Step 3: The ANF / MXene composite film is immersed in a hydroxyethyl cellulose dispersion, and then subjected to a second drying process to obtain an ANF / MXene-HEC triboelectric cathode material with a sandwich structure.

[0013] In step 1, the preparation method of the hydroxyethyl cellulose dispersion is as follows: at 45~55℃, 3~4g of hydroxyethyl cellulose powder is dissolved in 100~150mL of deionized water for 30~40min to obtain the hydroxyethyl cellulose dispersion; wherein, the viscosity of hydroxyethyl cellulose is 2600~3300mpa.s.

[0014] In step 1, the preparation of the aramid nanofiber mixed dispersion is as follows: First, an alkaline solution, para-aramid fibers, and dimethyl sulfoxide are stirred and mixed to obtain dispersion A; wherein, the mass ratio of para-aramid fibers to dimethyl sulfoxide is 2~3:200~300, the solute in the alkaline solution is potassium hydroxide, the concentration of the solute in the alkaline solution is 0.3~0.6g / mL, and the ratio of alkaline solution to para-aramid fibers is 1~2mL:2~3g;

[0015] Dispersion A was uniformly dispersed in deionized water, and then allowed to stand and filtered to obtain para-aramid nanofiber dispersion B; wherein the volume ratio of water to dispersion A was 1000~1500:50~100, and the concentration of para-aramid nanofiber dispersion was 1%~1.5%.

[0016] Preferably, in step 1, the MXene aqueous dispersion is a nanosheet MXene aqueous dispersion prepared by acid etching, and the concentration of the MXene dispersion is 20-25 mg / mL.

[0017] Preferably, in step 2, the solution ratio of aramid nanofiber dispersion and MXene dispersion is 80-100 mL: 3-5 mL, and the mixture is stirred for 15-20 min at 25-35°C until homogeneous.

[0018] Preferably, in step 2, the pressure during vacuum filtration is 0.08~0.10 MPa, the time is 3~4 h, and the filtration membrane is a mixed fiber membrane or a polytetrafluoroethylene membrane.

[0019] During the first drying process, the temperature is 95~105℃ and the drying time is 12~15min.

[0020] Preferably, in step 3, the concentration of the hydroxyethyl cellulose dispersion is 0.02–0.04 g / mL, and the impregnation time is 3–5 min.

[0021] Preferably, in step 3, the temperature during the second drying process is 60~70℃ and the time is 6~8h.

[0022] A triboelectric nanogenerator containing hydroxyethyl cellulose-aramid / MXene nano-triboelectric cathode material.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] This invention proposes a method for preparing a hydroxyethyl cellulose-aramid / MXene nano-triboelectric cathode material. This method involves vacuum filtration to composite aramid nanofibers and MXene into a film, which is then coated with hydroxyethyl cellulose to form a sandwich structure. This structure combines the high strength and high modulus of aramid with the high conductivity of MXene, along with an outer HEC protective layer, achieving a comprehensive improvement in charge transfer efficiency, stability, mechanical properties, and conductivity. HEC not only provides structural strength as a protective layer but also optimizes charge accumulation and transfer through its polar groups, significantly enhancing triboelectric power generation capabilities. Simultaneously, the synergistic effect of aramid and MXene enables the material to generate higher output voltage during triboelectric power generation and exhibits excellent long-term stability and high responsiveness under various environmental conditions, providing a more efficient and stable solution for applications in micro / nano energy harvesting and self-powered devices.

[0025] A sandwich structure is employed, with the inner layer consisting of a dense, layered film formed by vacuum filtration of a uniformly mixed dispersion of aramid nanofibers (ANF) and MXene under 0.1 MPa pressure. The outer layer is coated with a hydroxyethyl cellulose (HEC) protective layer. Aramid fibers provide high strength and high modulus, while the conductivity of MXene enhances charge transport capabilities. The outer HEC layer not only protects the inner MXene layer from oxidation but also enhances the overall structural strength, providing better mechanical stability and durability. Furthermore, the flexibility and stretchability of the HEC layer ensure that the material maintains excellent tribological properties under dynamic environments, improving the long-term reliability and stability of the entire power generation device.

[0026] As an outer protective film, HEC (hydrogen-coated electrolyte) has a surface rich in hydroxyl functional groups (-OH). These polar groups enhance the material's charge accumulation and transfer efficiency. During friction, the hydroxyl groups on the HEC surface effectively attract and fix charges. Simultaneously, the good lubricity of HEC reduces charge loss between the friction surfaces. The surface polar groups also promote electrostatic coupling induction, increasing the generation of triboelectric voltage. In triboelectric power generation, HEC not only serves as a protective layer but also as a highly efficient charge transfer channel, enhancing the speed and stability of charge transfer.

[0027] The composite of aramid nanofibers (ANF) and MXene produces a synergistic effect, enhancing the overall performance of the material. The high strength and modulus of aramid ensure the material's stability during friction, while the highly conductive MXene nanosheets form a conductive network within the film, promoting rapid charge conduction. The layered structure of MXene not only provides numerous ion-conducting channels but also enables efficient charge accumulation and transfer during friction, significantly improving the output of the triboelectric current. The composite of aramid fibers and MXene forms a tightly interwoven structure, allowing for rapid charge transfer between the fibers and MXene, thereby significantly improving charge storage capacity and triboelectric voltage output.

[0028] The composite of aramid nanofibers (ANF) and MXene exhibits a synergistic effect, significantly enhancing the triboelectric output performance and mechanical strength of the material. The high strength and high modulus of aramid ensure the stability of the material during friction, while the high conductivity and layered structure of MXene provide numerous ion-conducting channels, forming a conductive network that effectively promotes rapid charge conduction, improves charge accumulation and transfer efficiency, and significantly enhances the triboelectric voltage output. The tightly interwoven structure formed by the aramid fiber and MXene composite, with its hydrogen bonds and intermolecular forces, enhances the mechanical strength and flexibility of the composite film.

[0029] As an outer protective film, the hydrogen-coated polymer (HEC) layer enhances the material's charge retention capacity through hydrogen bonds and polar groups on its surface. When the material contacts and separates during friction, the HEC surface not only supports stable charge accumulation but also improves electrostatic coupling induction through optimized surface tribological properties, contributing to more efficient triboelectric voltage generation. Due to the HEC layer coating, the inner aramid / MXene composite film is protected, preventing surface damage during prolonged friction and ensuring long-term material stability and high response speed. This enhanced stability ensures that the triboelectric nanogenerator can continuously and stably output high voltage under various extreme operating conditions. Attached Figure Description

[0030] Figure 1 This is a structural diagram of a hydroxyethyl cellulose-aramid / MXene nano-triboelectric cathode material of the present invention;

[0031] Figure 2 This is a SEM cross-sectional image of a hydroxyethyl cellulose-aramid / MXene nano-triboelectric cathode material of the present invention;

[0032] Figure 3 This is a flowchart of a hydroxyethyl cellulose-aramid / MXene nano-triboelectric cathode material according to the present invention;

[0033] Figure 4 The triboelectric voltage is the triboelectric voltage of the hydroxyethyl cellulose-aramid / MXene nano-triboelectric cathode material prepared in Example 1 of this invention.

[0034] Figure 5 The triboelectric voltage is the triboelectric voltage of the hydroxyethyl cellulose-aramid / MXene nano-triboelectric cathode material prepared in Example 2 of this invention.

[0035] Figure 6 The triboelectric voltage is the triboelectric voltage of the hydroxyethyl cellulose-aramid / MXene nano-triboelectric cathode material prepared in Example 3 of this invention.

[0036] Figure 7 The triboelectric voltage of the hydroxyethyl cellulose-aramid / MXene nano-triboelectric cathode material prepared in Example 4 of this invention;

[0037] Figure 8 The triboelectric voltage is the triboelectric voltage of the hydroxyethyl cellulose-aramid / MXene nano-triboelectric cathode material prepared in Example 5 of this invention. Detailed Implementation

[0038] The present invention will be further described in detail below with reference to specific embodiments. These descriptions are for explanation purposes only and are not intended to limit the scope of the invention.

[0039] This invention discloses a hydroxyethyl cellulose-aramid / MXene nano-triboelectric cathode material, with reference to... Figure 1 The cathode material has a sandwich structure, with an inner layer of aramid / MXene vacuum-filtered composite film and an outer layer of hydroxyethyl cellulose protective layer. Figure 2 The SEM cross-sectional image of the aramid / MXene triboelectric cathode material clearly shows two relatively thick hydroxyethyl cellulose membranes on the top and bottom layers wrapping the aramid / MXene vacuum-filtered composite film in the middle, further verifying the sandwich structure.

[0040] Hydroxyethyl cellulose (HEC) is preferred as the contact friction layer. Its advantages are: (1) Excellent film-forming and processability: Hydroxyethyl cellulose has good film-forming and solubility, and can uniformly coat the surface of the composite material to form a continuous and smooth protective film. At the same time, the preparation process of HEC dispersion is simple, and the cost is low and the source is wide, which is convenient for large-scale processing, production and application; (2) Outstanding surface friction properties: Hydroxyethyl cellulose (HEC) is composed of cellulose main chain and hydroxyethyl side chain structure. It is a water-soluble polymer compound obtained by etherification reaction of cellulose with ethylene oxide (or chloroethanol). The surface is rich in hydroxyl groups. The hydroxyl groups help to attract charge transfer in electrostatic coupling induction, which has the inherent advantage of preparing high triboelectric voltage positive electrode materials; (3) Biocompatibility and environmental friendliness: HEC is a renewable and environmentally friendly material with good biocompatibility and non-toxicity. It is widely used in medical and cosmetic fields. As a triboelectric nano-power generation material, it has great advantages in the application of flexible wearables. (4) Flexibility and stretchability: As a flexible polymer, HEC film can endow triboelectric nanomaterials with good flexibility and a certain degree of stretchability, making them suitable for flexible electronic devices and wearable devices. Compared with traditional rigid materials, after HEC is combined with aramid / MXene composite film, the material can still maintain good electrical properties when bent or stretched, which improves its reliability in dynamic environments.

[0041] The advantages of using aramid nanofibers and MXene nanosheets to form an inner layer film material for vacuum filtration are: (1) outstanding mechanical properties: aramid nanofibers have a linear rigid straight chain configuration due to the macromolecular chains composed of benzene rings and amide groups. They are not easily deformed when the fiber is subjected to force, and have the characteristics of high strength and high modulus. The combination of MXene and HEC forms a composite film, which improves the overall mechanical and tribological properties of the material through stress transfer; (2) high conductivity: the free electron transport of metal atoms in the MXene layer, the formation of the electron conjugation system, the ion conduction channels in the interlayer voids, and the excellent physical and chemical properties give it good conductivity; the composite with aramid nanofibers forms a tightly interwoven layered structure, which can store and retain charges well; (3) excellent temperature resistance and stability: aramid nanofibers have the characteristics of high temperature resistance, corrosion resistance, and wear resistance. They maintain stable triboelectric power generation performance in a wide temperature range and harsh chemical environment, which is conducive to extending the service life of triboelectric nanofiber power generation materials. (4) Good flexibility and stretchability: The layered structure of MXene and the aramid nanofibers intertwine to form a composite film with excellent flexibility and stretchability, which is conducive to the wide application of the material in the fields of flexible, wearable and micro-nano energy harvesting.

[0042] This invention also discloses a hydroxyethyl cellulose-aramid / MXene nano-triboelectric cathode material, with reference to... Figure 3 This includes the following steps:

[0043] Step 1: Dissolve 3-4g of hydroxyethyl cellulose powder in 100-150mL of deionized water at 45-55℃ for 30-40 minutes to obtain a hydroxyethyl cellulose dispersion with a concentration of 0.02-0.04g / mL.

[0044] Dispersion A is obtained by stirring and mixing an alkaline solution, para-aramid fibers, and dimethyl sulfoxide; wherein the mass ratio of para-aramid fibers to dimethyl sulfoxide is 2~3:200~300, the solute in the alkaline solution is potassium hydroxide, the concentration of the solute in the alkaline solution is 0.3~0.6g / mL, and the ratio of alkaline solution to para-aramid fibers is 1~2mL:2~3g;

[0045] Dispersion A was uniformly dispersed in deionized water, and then allowed to stand and filtered to obtain para-aramid nanofiber dispersion B; wherein the volume ratio of water to dispersion A was 1000~1500:50~100, and the concentration of para-aramid nanofiber dispersion was 1%~1.5%.

[0046] Step 2: Mix 80-100 mL of aramid nanofiber dispersion (1%-1.5%) and 3-5 mL of MXene dispersion (20-25 mg / mL) at 25-35°C for 15-20 min until homogeneous. Then, vacuum filter the mixture under 0.08-0.10 MPa pressure for 3-4 h and dry it at 95-105°C for 12-15 min to obtain the ANF / MXene composite film.

[0047] Step 3: Immerse the ANF / MXene composite film in a hydroxyethyl cellulose dispersion for 3-5 minutes, and then dry it at 60-70°C for 6-8 hours to finally obtain the ANF / MXene-HEC triboelectric cathode material with a sandwich structure.

[0048] Example 1

[0049] Step 1: Dissolve 3g of hydroxyethyl cellulose powder in 150mL of deionized water at 55℃ for 30min to obtain a hydroxyethyl cellulose dispersion with a concentration of 0.02g / mL.

[0050] Step 2: Mix 100 mL of 1% aramid nanofiber dispersion and 3 mL of 25 mg / mL MXene dispersion at 25 °C for 20 min. After mixing evenly, vacuum filter under 0.08 MPa pressure for 3 h. Then dry at 105 °C for 15 min to obtain ANF / MXene composite film.

[0051] Step 3: Immerse the ANF / MXene composite film in a hydroxyethyl cellulose dispersion for 3 minutes, and then dry it at 60°C for 6 hours to finally obtain the sandwich-structured ANF / MXene-HEC triboelectric cathode material.

[0052] In this embodiment, a hydroxyethyl cellulose-aramid / MXene nano-triboelectric cathode material is provided, with a hydroxyethyl cellulose concentration of 0.2 g / ml, an MXene content of 75 mg, a composite film thickness of 0.0049 mm, a tensile strength of 10.89 MPa, and a triboelectric voltage of 640 V.

[0053] Example 2

[0054] Step 1: Dissolve 3g of hydroxyethyl cellulose powder in 150mL of deionized water at 55℃ for 30min to obtain a hydroxyethyl cellulose dispersion with a concentration of 0.02g / mL.

[0055] Step 2: Mix 100 mL of 1.5% aramid nanofiber dispersion and 4 mL of 25 mg / mL MXene dispersion at 25 °C for 20 min. After mixing evenly, vacuum filter under 0.08 MPa pressure for 3 h, and then dry at 105 °C for 15 min to obtain ANF / MXene composite film.

[0056] Step 3: Immerse the ANF / MXene composite film in a hydroxyethyl cellulose dispersion for 3 minutes, and then dry it at 60°C for 6 hours to finally obtain the sandwich-structured ANF / MXene-HEC triboelectric cathode material.

[0057] In this embodiment, a hydroxyethyl cellulose-aramid / MXene nano-triboelectric cathode material is provided, with a hydroxyethyl cellulose concentration of 0.2 g / ml, an MXene content of 100 mg, a composite film thickness of 0.0052 mm, a tensile strength of 11.23 MPa, and a triboelectric voltage of 680 V.

[0058] Example 3

[0059] Step 1: Dissolve 3g of hydroxyethyl cellulose powder in 100mL of deionized water at 55℃ for 35min to obtain a hydroxyethyl cellulose dispersion with a concentration of 0.03g / mL.

[0060] Step 2: Mix 100 mL of 1.5% aramid nanofiber dispersion and 3 mL of 25 mg / mL MXene dispersion at 25 °C for 20 min. After mixing evenly, vacuum filter under 0.08 MPa pressure for 4 h, and then dry at 105 °C for 15 min to obtain ANF / MXene composite film.

[0061] Step 3: Immerse the ANF / MXene composite film in a hydroxyethyl cellulose dispersion for 3 minutes, and then dry it at 60°C for 7 hours to finally obtain the sandwich-structured ANF / MXene-HEC triboelectric cathode material.

[0062] In this embodiment, a hydroxyethyl cellulose-aramid / MXene nano-triboelectric cathode material is provided, with a hydroxyethyl cellulose concentration of 0.3 g / ml, an MXene content of 75 mg, a composite film thickness of 0.0065 mm, a tensile strength of 13.89 MPa, and a triboelectric voltage of 732 V.

[0063] Example 4

[0064] Step 1: Dissolve 3g of hydroxyethyl cellulose powder in 100mL of deionized water at 55℃ for 35min to obtain a hydroxyethyl cellulose dispersion with a concentration of 0.03g / mL.

[0065] Step 2: Mix 100 mL of 1.5% aramid nanofiber dispersion and 5 mL of 25 mg / mL MXene dispersion at 25 °C for 20 min. After mixing evenly, filter under vacuum at 0.08 MPa for 4 h. Then dry at 105 °C for 15 min to obtain ANF / MXene composite film.

[0066] Step 3: Immerse the ANF / MXene composite film in a hydroxyethyl cellulose dispersion for 3 minutes, and then dry it at 60°C for 7 hours to finally obtain the sandwich-structured ANF / MXene-HEC triboelectric cathode material.

[0067] In this embodiment, a hydroxyethyl cellulose-aramid / MXene nano-friction cathode material is provided, with a hydroxyethyl cellulose concentration of 0.3 g / ml, an MXene content of 125 mg, a composite film thickness of 0.0081 mm, a tensile strength of 14.56 MPa, and a triboelectric voltage of 860 V.

[0068] Example 5

[0069] Step 1: Dissolve 4g of hydroxyethyl cellulose powder in 100mL of deionized water at 55℃ for 40min to obtain a hydroxyethyl cellulose dispersion with a concentration of 0.04g / mL.

[0070] Step 2: Mix 100 mL of 1.5% aramid nanofiber dispersion and 5 mL of 25 mg / mL MXene dispersion at 25 °C for 20 min. After mixing evenly, filter under vacuum at 0.08 MPa for 4 h. Then dry at 105 °C for 15 min to obtain ANF / MXene composite film.

[0071] Step 3: Immerse the ANF / MXene composite film in hydroxyethyl cellulose dispersion for 3 min, and then dry it at 60°C for 8 h to finally obtain the sandwich-structured ANF / MXene-HEC triboelectric cathode material.

[0072] In this embodiment, a hydroxyethyl cellulose-aramid / MXene nano-triboelectric cathode material is provided, with a hydroxyethyl cellulose concentration of 0.4 g / ml, an MXene content of 125 mg, a composite film thickness of 0.0096 mm, a tensile strength of 14.32 MPa, and a triboelectric voltage of 1012 V.

[0073] Table 1 Technical parameters of the high triboelectric voltage sensing materials obtained in Examples 1-5

[0074]

[0075] In the triboelectric voltage test, 5*5cm square pieces of hydroxyethyl cellulose-aramid / MXene nano-triboelectric positive electrode material were first cut. Copper foil tape and wires were then attached to the back of each piece in a grid-like structure to prepare the positive electrode device of the triboelectric nanogenerator. Similarly, the negative electrode device of the triboelectric nanogenerator was prepared using a polytetrafluoroethylene film. The positive and negative electrode materials were connected to an oscilloscope, and a linear motor was used to apply a uniform and stable impact force, causing the positive and negative electrodes to separate, resulting in charge transfer and the generation of triboelectric voltage.

[0076] Table 1 shows the technical parameters of the hydroxyethyl cellulose-aramid / MXene nano-triboelectric cathode materials prepared in Examples 1-5. It can be seen that the triboelectric cathode materials prepared by the process route provided by this invention benefit from the use of a hydroxyethyl cellulose film as the contact friction layer. Hydroxyethyl cellulose has good charge transfer capabilities, which is beneficial for generating triboelectric voltage and provides good electrostatic coupling induction and triboelectric power generation capabilities. The higher the concentration of hydroxyethyl cellulose, the thicker the outer shell film, and the higher the triboelectric output voltage of the material.

[0077] The introduction of aramid nanofibers enhances the toughness and strength of the material, achieving a mechanical strength in the range of 10-15 MPa. As the concentration of hydroxyethyl cellulose (HEC) increases and the HEC-PVDF-HEC film becomes thicker, the mechanical strength also increases. The triboelectric voltage is significantly affected by the thickness of the hydroxyethyl film; a thicker cathode material results in stronger electrostatic coupling charge transfer, more electron loss, a larger potential difference between the positive and negative electrodes, and thus a higher triboelectric voltage. Similarly, the wide-bandgap charge-retaining PVDF film effectively improves charge accumulation and transport efficiency, thereby increasing the material's output triboelectric voltage. This structural design not only enhances the overall performance of the material but also improves the output stability and sensitivity of the nano-triboelectric generator.

[0078] Figures 3-7 The triboelectric output voltage of the hydroxyethyl cellulose-aramid / MXene nano-triboelectric positive electrode material prepared in Examples 1-5 was used to prepare a 5*5cm square triboelectric power generation device by using a polytetrafluoroethylene film as the negative electrode. Under the same frequency and external force, different triboelectric output voltages were generated due to the different concentrations of hydroxyethyl cellulose and aramid / MXene composite film.

[0079] The above description is merely a preferred embodiment of the present invention and is not intended to limit the technical solution of the present invention in any way. Those skilled in the art should understand that, without departing from the spirit and principles of the present invention, the technical solution can be modified and replaced in several simple ways, and these modifications and replacements are all within the scope of protection covered by the claims.

Claims

1. A hydroxyethyl cellulose-aramid / MXene nano-triboelectric cathode material, characterized in that, The cathode material has a sandwich structure, with an inner layer of aramid / MXene vacuum-filtered composite film and an outer layer of hydroxyethyl cellulose protective layer. The preparation method of hydroxyethyl cellulose-aramid / MXene nano-triboelectric cathode material is as follows: Step 1: Prepare hydroxyethyl cellulose dispersion, aramid nanofiber dispersion and MXene dispersion; The preparation of the aramid nanofiber mixed dispersion is as follows: First, an alkaline solution, para-aramid fibers, and dimethyl sulfoxide are stirred and mixed to obtain dispersion A; wherein, the mass ratio of para-aramid fibers to dimethyl sulfoxide is 2~3:200~300, the solute of the alkaline solution is potassium hydroxide, the concentration of the solute in the alkaline solution is 0.3~0.6g / mL, and the ratio of alkaline solution to para-aramid fibers is 1~2mL:2~3g; Dispersion A was uniformly dispersed in deionized water, and then allowed to stand and filtered to obtain para-aramid nanofiber dispersion B; wherein the volume ratio of water to dispersion A was 1000~1500:50~100, and the concentration of para-aramid nanofiber dispersion was 1%~1.5%; The MXene aqueous dispersion is a nanosheet MXene aqueous dispersion prepared by acid etching, and the concentration of the MXene dispersion is 20-25 mg / mL. The specific preparation method of hydroxyethyl cellulose dispersion is as follows: at 45~55℃, 3~4g of hydroxyethyl cellulose powder is dissolved in 100~150mL of deionized water for 30~40min to obtain hydroxyethyl cellulose dispersion; wherein, the viscosity of hydroxyethyl cellulose is 2600~3300mpa.s; Step 2: After uniformly mixing the aramid nanofiber dispersion and the MXene dispersion, an ANF / MXene composite membrane is prepared by vacuum filtration and a first drying process. The solution ratio of aramid nanofiber dispersion and MXene dispersion is 80-100 mL: 3-5 mL; Step 3: The ANF / MXene composite film is impregnated in a hydroxyethyl cellulose dispersion, and then subjected to a second drying process to obtain an ANF / MXene-HEC triboelectric cathode material with a sandwich structure; During impregnation, the concentration of the hydroxyethyl cellulose dispersion is 0.02–0.04 g / mL, and the impregnation time is 3–5 min.

2. A method for preparing the hydroxyethyl cellulose-aramid / MXene nano-triboelectric cathode material as described in claim 1, characterized in that, Includes the following steps: Step 1: Prepare hydroxyethyl cellulose dispersion, aramid nanofiber dispersion and MXene dispersion; Step 2: After uniformly mixing the aramid nanofiber dispersion and the MXene dispersion, an ANF / MXene composite membrane is prepared by vacuum filtration and a first drying process. Step 3: The ANF / MXene composite film is immersed in a hydroxyethyl cellulose dispersion, and then subjected to a second drying process to obtain an ANF / MXene-HEC triboelectric cathode material with a sandwich structure.

3. The method for preparing the hydroxyethyl cellulose-aramid / MXene nano-triboelectric cathode material according to claim 2, characterized in that, In step 1, the preparation method of the hydroxyethyl cellulose dispersion is as follows: at 45~55℃, 3~4g of hydroxyethyl cellulose powder is dissolved in 100~150mL of deionized water for 30~40min to obtain the hydroxyethyl cellulose dispersion; wherein, the viscosity of hydroxyethyl cellulose is 2600~3300mpa.s.

4. The method for preparing the hydroxyethyl cellulose-aramid / MXene nano-triboelectric cathode material according to claim 2, characterized in that, In step 1, the preparation of the aramid nanofiber mixed dispersion is as follows: First, an alkaline solution, para-aramid fibers, and dimethyl sulfoxide are stirred and mixed to obtain dispersion A; wherein, the mass ratio of para-aramid fibers to dimethyl sulfoxide is 2~3:200~300, the solute in the alkaline solution is potassium hydroxide, the concentration of the solute in the alkaline solution is 0.3~0.6g / mL, and the ratio of alkaline solution to para-aramid fibers is 1~2mL:2~3g; Dispersion A was uniformly dispersed in deionized water, and then allowed to stand and filtered to obtain para-aramid nanofiber dispersion B; wherein the volume ratio of water to dispersion A was 1000~1500:50~100, and the concentration of para-aramid nanofiber dispersion was 1%~1.5%.

5. The method for preparing the hydroxyethyl cellulose-aramid / MXene nano-triboelectric cathode material according to claim 2, characterized in that, In step 1, the MXene aqueous dispersion is a nanosheet MXene aqueous dispersion prepared by acid etching, and the concentration of the MXene dispersion is 20-25 mg / mL.

6. The method for preparing the hydroxyethyl cellulose-aramid / MXene nano-triboelectric cathode material according to claim 2, characterized in that, In step 2, the solution ratio of aramid nanofiber dispersion and MXene dispersion is 80-100 mL: 3-5 mL, and the mixture is stirred for 15-20 min at 25-35℃ until homogeneous.

7. The method for preparing the hydroxyethyl cellulose-aramid / MXene nano-triboelectric cathode material according to claim 2, characterized in that, In step 2, during vacuum filtration, the pressure is 0.08~0.10 MPa, the time is 3~4 hours, and the filtration membrane is a mixed fiber membrane or a polytetrafluoroethylene membrane. During the first drying process, the temperature is 95~105℃ and the drying time is 12~15min.

8. The method for preparing the hydroxyethyl cellulose-aramid / MXene nano-triboelectric cathode material according to claim 2, characterized in that, In step 3, the concentration of the hydroxyethyl cellulose dispersion is 0.02–0.04 g / mL, and the impregnation time is 3–5 min.

9. The method for preparing the hydroxyethyl cellulose-aramid / MXene nano-triboelectric cathode material according to claim 2, characterized in that, In step 3, the second drying process is carried out at a temperature of 60-70℃ for 6-8 hours.

10. A triboelectric nanogenerator comprising the hydroxyethyl cellulose-aramid / MXene nanotriboelectric cathode material as described in claim 1.

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