Flexible wearable sensing ANF / MXene friction positive electrode material and preparation method thereof

Abstract

The invention discloses a flexible wearable sensing ANF / MXene friction positive electrode material and a preparation method thereof, and belongs to the fields of friction nanometer power generation, micro-nano energy collection, flexible wearable sensing and the like, a nanometer power generation device constructs a three-dimensional interwoven structure with high mechanical strength and conductivity through compounding of aramid nanometer fibers (ANF) and molecular-level intercalation of MXene, and the flexible wearable sensing ANF / MXene friction positive electrode material is applied to the field of friction nanometer power generation, micro-nano energy collection, flexible wearable sensing and the like. The effective contact area is increased by combining a multi-stage micro-nano groove formed by an MXene sheet layer, an efficient polarization couple is formed by the MXene sheet layer and a PTFE film, the charge density and the output performance are remarkably improved, an interface hydrogen bond network is optimized by adopting a vacuum directional arrangement process, MXene agglomeration is inhibited, and the charge capture capability is enhanced. The device can synchronously realize mechanical energy collection and multi-mode sensing functions, has high sensitivity and long cycle life, and provides an efficient and reliable solution for wearable electronic equipment, a self-powered sensing system and an Internet of Things terminal.

Description

Technical Field

[0001] The present invention relates to the fields of triboelectric nanogeneration, micro-nano energy harvesting, flexible wearable sensing, etc., and specifically relates to a flexible wearable sensing ANF / MXene triboelectric positive electrode material and a preparation method thereof. Background Art

[0002] As an emerging energy harvesting technology, the triboelectric nanogenerator (TENG) directly converts the mechanical energy widely existing in the environment (such as human movement, air flow vibration, etc.) into electrical energy through the synergistic effect of the triboelectrification effect and electrostatic induction, providing an idea for solving the self-power supply requirements of microelectronic devices. However, the actual application efficiency of TENG highly depends on the charge density of the friction material, the interface contact efficiency, and the long-term stability, which makes the design of the material system the core challenge for technological breakthrough.

[0003] Although traditional polymer materials (such as polyvinylidene fluoride PVDF) have excellent charge retention ability, their low surface polarity and smooth structure lead to low friction contact efficiency and it is difficult to achieve high charge density output. Para-aramid fiber exhibits excellent mechanical strength (tensile strength > 20 cN / dtex) and thermal stability (thermal decomposition temperature > 500 °C) due to the strong hydrogen bonds and π-π stacking interactions between molecular chains, but the lack of surface polar groups with a high degree of crystallization results in limited charge transfer efficiency at the friction interface.

[0004] Two-dimensional material MXene (such as Ti 3 C 2 Tx) can serve as a "highway" for charge transport in TENG due to its unique layered structure and metallic conductivity. However, the rich functional groups (-OH, -O, etc.) on its surface lead to too strong van der Waals forces between the sheets, which is prone to irreversible agglomeration. Especially during the dynamic friction process, the interlayer slip causes the structure to collapse, resulting in the fracture of the conductive network. In addition, the oxidation sensitivity of MXene causes its performance to decay rapidly in a humid environment, restricting the long-term reliability of the device.

[0005] Currently, flexible triboelectric nanogenerators (TENG) generally face bottlenecks such as weak interfacial bonding of heterogeneous materials, low charge density, and poor dynamic stability. Traditional composite strategies (such as physical blending) lead to interface delamination due to the polarity mismatch between aramid fiber and MXene, significant interfacial energy dissipation during the friction process, and insufficient contact area of rigid materials, which exacerbates mechanical wear and causes charge output attenuation. Summary of the Invention

[0006] In view of the deficiencies of traditional materials in mechanical strength, friction performance, and charge retention, the present invention provides a flexible wearable sensing ANF / MXene triboelectric positive electrode material and a preparation method thereof, and proposes a three-dimensional intertwined structure-based ANF / MXene-PTFE composite film technology: through the molecular-level intercalation composite of aramid nanofibers (ANF) and MXene, an interpenetrating network with both high modulus and high conductivity is constructed, and the charge capture efficiency is optimized by combining surface polar groups; at the same time, a PTFE negative friction layer and a PVC encapsulation structure are introduced to construct a super-sensitive, tough and stable triboelectric nanogenerator device. This technology breaks through the limitation of insufficient interfacial synergy of traditional materials and provides an innovative solution for high-sensitivity wearable devices and self-powered sensing systems.

[0007] The present invention is realized through the following technical solutions: A flexible wearable sensing ANF / MXene triboelectric positive electrode material, comprising the following steps: Step 1, prepare an aramid nanofiber dispersion and an MXene dispersion; Step 2, mix the aramid nanofiber dispersion and the MXene dispersion evenly in proportion, make a composite film by vacuum filtration, and perform vacuum drying treatment to obtain an ANF / MXene composite film.

[0008] Preferably, in Step 1, the preparation of the aramid nanofiber mixed dispersion is as follows: First, stir and mix an alkaline solution, para-aramid fibers, and dimethyl sulfoxide to obtain dispersion A; wherein, the mass ratio of para-aramid fibers to dimethyl sulfoxide is 1-2:400-500, the solute of the alkaline solution is potassium hydroxide, the concentration of the solute in the alkaline solution is 0.5-0.7 g / mL, and the ratio of the alkaline solution to para-aramid fibers is 1-2 mL:1-2 g; Disperse dispersion A evenly into deionized water, and then let it stand and filter to obtain a para-aramid nanofiber dispersion B; wherein, the volume ratio of water to dispersion A is 80-100:1000-1200, and the concentration of the para-aramid nanofiber dispersion is 0.02%-0.03%.

[0009] Preferably, in Step 1, the MXene aqueous dispersion is a nanosheet MXene aqueous dispersion prepared by an acid etching method, and the concentration of the MXene dispersion is 30-40 mg / mL.

[0010] Preferably, in Step 2, the solution ratio of the aramid nanofiber dispersion and the MXene dispersion is 1000-1200 mL:3-5 mL, and they are stirred and mixed evenly for 20-30 min at 25-35 °C.

[0011] Preferably, in step 2, during vacuum filtration, the pressure is 0.08 - 0.10 Mpa, the time is 2 - 3 h, and the filtration membrane is a 0.02-μm mixed fiber filter membrane.

[0012] Preferably, in step 2, during vacuum drying, the temperature is 95 - 105 °C, and the drying time is 12 - 15 min.

[0013] An ANF / MXene composite film obtained by the preparation method of the ANF / MXene triboelectric positive electrode material for flexible wearable sensing as described above.

[0014] A triboelectric nanogenerator device, which uses the ANF / MXene composite film as the triboelectric positive electrode and PTFE as the triboelectric negative electrode. Its preparation method is as follows: The ANF / MXene composite film and the PTFE film are both pasted with copper foil tape and wires in a grid structure to make the positive electrode sheet and the negative electrode sheet respectively, and then they are encapsulated with PVC to form a flexible wearable ANF / MXene-PTFE triboelectric nanogenerator device.

[0015] Preferably, the thickness of the PTFE film is 0.1 - 0.3 mm, the dynamic friction coefficient is 0.06 - 0.08, and the specific gravity is 2.1 - 2.3 g / cm 3 ; The thickness of the copper foil tape is 0.04 - 0.06 mm, and the thickness of the PVC tape is 0.02 - 0.03 mm.

[0016] A sensor, which uses the ANF / MXene composite film as the triboelectric positive electrode and PTFE as the triboelectric negative electrode, and is encapsulated with PVC to form a flexible wearable ANF / MXene-PTFE triboelectric nanosensor.

[0017] Compared with the prior art, the present invention has the following beneficial effects: Aiming at the problems of low tensile strength (<60 MPa) and interface delamination of traditional MXene-based TENGs, a flexible wearable sensing ANF / MXene friction positive electrode material of the present invention is prepared by vacuum filtration composite of aramid nanofibers (ANF) and MXene to construct a dense layered structure with a tensile strength of 100 MPa, which is significantly improved compared with pure MXene films. By constructing an internal conductive network path through the ANF / MXene layer, the charge transfer path is shortened to the nanoscale, thereby increasing the interfacial charge density. Specifically, the amide bonds of ANF and -OH of MXene form a hydrogen bond network, effectively blocking the stacking of MXene sheets and exposing more surface end groups (-O, -F), thus enhancing the electron capture ability. At the same time, the layered structure of MXene forms multi-level micro-nano grooves in the ANF network, increasing the effective contact area. Combining the electron capture of PTFE and the ion adsorption synergistic effect of MXene, the half-life of the output voltage is extended.

[0018] Furthermore, traditional MXene films are prone to cracking due to humidity expansion. Through ANF / MXene gradient mixing (volume ratio 80 - 100 mL: 3 - 5 mL) and low-pressure directional arrangement (0.08 - 0.10 MPa), a three-dimensional intertwined network structure is formed (as shown in Figure 2 , 3 ), in which the humidity deformation rate of the composite film is reduced.

[0019] Furthermore, the high strength of ANF (tensile strength > 20 cN / dtex) and the anchoring effect of MXene (which can form strong hydrogen bonds or van der Waals forces) endow the film with excellent tear resistance. By forming an aramid nanofiber intertwined network through vacuum filtration, the tensile strength, fold resistance and flexibility of the film are improved, making it suitable for applications such as flexible wearable devices.

[0020] A friction nanogenerator device of the present invention uses copper foil / PVC tape for flexible packaging, which isolates external interference while maintaining the stability of the conductive interface, and has excellent bending resistance, significantly superior to traditional epoxy resin packaging. After testing, the device can still maintain stable output performance in a wide temperature range of -20~200°C and extreme environments such as acids, alkalis and underwater. Specifically, through the design of the ANF / MXene-PTFE composite structure, hydrogen bond-mediated interfacial charge regulation and low-pressure directional process optimization, the bottlenecks of traditional TENGs in mechanical strength, charge density and environmental stability are broken through, and the output voltage reaches 142.22V, providing a high-performance solution for flexible wearable devices, industrial Internet of Things and self-driven medical monitoring. Brief Description of the Drawings

[0021] Figure 1 is a flow chart of a preparation method of a flexible wearable sensing ANF / MXene friction positive electrode material of the present invention; Figure 2 This is the SEM cross-sectional view of the ANF / MXene triboelectric positive electrode material for flexible wearable sensing of the present invention; Figure 3 This is the SEM cross-sectional view of the ANF / MXene triboelectric positive electrode material for flexible wearable sensing of the present invention; Figure 4 This is the structural diagram of the ANF / MXene-PTFE triboelectric nanogenerator device for flexible wearable sensing of the present invention; Figure 5 This is the mechanical tensile strength of the ANF / MXene triboelectric nanogenerator materials for flexible wearable sensing prepared in Examples 1-5 of the present invention; Figure 6 This is the triboelectric voltage of the ANF / MXene-PTFE triboelectric nanogenerator devices for flexible wearable sensing prepared in Examples 1-5 of the present invention. Detailed implementation manners

[0022] The following further elaborates on the present invention in combination with specific embodiments, which is an explanation rather than a limitation of the present invention.

[0023] The present invention discloses an ANF / MXene triboelectric positive electrode material for flexible wearable sensing, including the following steps: Step 1, prepare an aramid nanofiber dispersion and an MXene dispersion. Specifically: The preparation of the aramid nanofiber mixed dispersion is as follows: First, stir and mix an alkaline solution, para-aramid fiber, and dimethyl sulfoxide to obtain dispersion A; wherein, the mass ratio of para-aramid fiber to dimethyl sulfoxide is 1-2:400-500, the solute of the alkaline solution is potassium hydroxide, the concentration of the solute in the alkaline solution is 0.5-0.7 g / mL, and the ratio of the alkaline solution to para-aramid fiber is 1-2 mL:1-2 g; Disperse dispersion A evenly into deionized water, and then let it stand and filter to obtain para-aramid nanofiber dispersion B; wherein, the volume ratio of water to dispersion A is 80-100:1000-1200, and the concentration of the para-aramid nanofiber dispersion is 0.02%-0.03%.

[0024] The MXene aqueous dispersion is a nanosheet MXene aqueous dispersion prepared by an acid etching method, and the concentration of the MXene dispersion is 30-40 mg / mL.

[0025] Step 2: Disperse 1000 - 1200 mL of aramid nanofiber dispersion with a concentration of 0.02% - 0.03% and 3 - 5 mL of MXene dispersion with a concentration of 30 - 40 mg / mL at 25 - 35°C and stir for 20 - 30 min until evenly mixed. Then, perform vacuum filtration under a pressure of 0.08 - 0.10 Mpa for 2 - 3 h, and then dry at 95 - 105°C for 12 - 15 min to obtain the ANF / MXene composite film.

[0026] The present invention also discloses an ANF / MXene composite film obtained by the preparation method of a flexible wearable sensing ANF / MXene triboelectric positive electrode material. Referring to Figure 2 、 3 ,the main substrate of the ANF / MXene composite film is an aramid film, which is in a sheet-like shape after filtration. At 10.0 mm × 30.0 k, a three-dimensional intertwined structure of ANF and MXene fibers can be observed. The tensile strength of the traditional PVDF material is 30 - 50 Mpa, while in comparison, the tensile strength of the ANF-MXene composite film proposed by the present invention can reach 100 - 120 MPa.

[0027] The present invention also discloses a triboelectric nanogenerator device, as Figure 3 shown. This device uses the flexible wearable sensing ANF / MXene triboelectric positive electrode material as the triboelectric positive electrode and PTFE as the triboelectric negative electrode. The preparation method is as follows: Post copper foil tapes and wires on the ANF / MXene composite film and the PTFE film according to a grid structure to make the positive electrode sheet and the negative electrode sheet respectively, and then encapsulate them with PVC to form a flexible wearable ANF / MXene-PTFE triboelectric nanogenerator device.

[0028] The specific steps are as follows: First, cut an ANF / MXene composite film with a size of 20 * 20 mm. According to the grid structure, stick a 20 * 5 mm copper foil tape every 2.5 mm, and finally stick a 20 * 5 mm copper foil tape horizontally and connect the wires to make the triboelectric nanogenerator positive electrode.

[0029] Then, on the surface of a PTFE film with a size of 20 * 20 mm, a thickness of 0.1 - 0.3 mm, a dynamic friction coefficient of 0.06 - 0.08, and a specific gravity of 2.1 - 2.3 g / cm 3 ,stick a 20 * 5 mm copper foil tape every 2.5 mm according to the grid structure, and finally stick a 20 * 5 mm copper foil tape horizontally and connect the wires to make the triboelectric nanogenerator negative electrode.

[0030] Finally, the smooth surfaces of the positive electrode ANF / MXene composite film and the negative electrode PTFE film are brought into contact, and the positive and negative electrodes are encapsulated using PVC tape to obtain an ANF / MXene-PTFE triboelectric nanogenerator device.

[0031] In this invention, a triboelectric nanogenerator device preferably uses ANF (aramid nanofiber) as the substrate material, MXene as the polar group filler, PTFE (polytetrafluoroethylene) as the negative friction layer material, and PVC (polyvinyl chloride) as the surface encapsulation material. ANF provides mechanical support and polarity regulation. MXene enhances conductivity and charge transfer. The two form a stable interpenetrating network through hydrogen bonds and van der Waals forces, solving the problem of interface delamination. The high electronegativity of PTFE and the ion adsorption ability of MXene together improve the charge density and retention. Through the PVC ultra-thin flexible encapsulation technology, the device is made lightweight, bend-resistant, and adaptable to extreme environments, meeting the dual requirements of wearable devices for mechanical robustness and environmental tolerance. Through the collaborative design of the above material system, this invention breaks through the limitations of traditional TENG in terms of strength, charge density, and stability, providing a high-performance solution for flexible wearable sensing and self-powered systems.

[0032] Specifically, ANF (aramid nanofiber) provides the basis for high tensile strength and tear resistance for the composite film due to the strong hydrogen bonds and π-π stacking between molecular chains. Its nanometerization treatment not only increases the specific surface area but also forms a hydrogen bond network with the hydroxyl groups of MXene through surface amide bonds, effectively inhibiting the agglomeration of MXene sheets. At the same time, it exposes polar groups to optimize the charge capture ability, solving the problem of insufficient mechanical stability of traditional MXene-based materials caused by brittleness and interface delamination. In addition, the high thermal stability (thermal decomposition temperature > 500 °C) and chemical inertness of ANF itself enable it to maintain structural integrity under extreme environments such as high temperature, acid, and alkali, providing a key guarantee for the long-term reliable operation of the device.

[0033] MXene (such as Ti 3 C 2 Tx) has ultra-high conductivity. Its two-dimensional layered structure provides a fast channel for charge transport. At the same time, after being compounded with ANF, it forms multi-level micro-nano grooves, significantly increasing the effective frictional contact area. The rich functional groups (OH, O, etc.) on the surface of MXene enhance the interface polarity, promote charge transfer, and form a stable interpenetrating network through hydrogen bonding with ANF. The ion adsorption ability, and the ion adsorption characteristics of the interlayer voids cooperate with the electron capture effect of PTFE, significantly extending the charge half-life and enhancing the stability of the material.

[0034] PTFE (polytetrafluoroethylene), as the negative friction layer, forms a significant work function difference with the ANF / MXene positive electrode due to its high electronegativity and low friction coefficient, reducing mechanical wear while increasing the charge density. Its chemical inertness and hydrophobic properties further ensure the stability of the device in complex environments.

[0035] The ultra-thin PVC tape achieves lightweight packaging (total thickness < 0.5 mm), isolates water and oxygen penetration with high chemical stability and interfacial adhesion, protects MXene from oxidation erosion, and enables the device to withstand repeated bending through its flexible and extensible properties, thus achieving a balance among mechanical robustness, environmental tolerance, and signal stability.

[0036] The present invention also discloses a sensor, which uses a flexible wearable sensing ANF / MXene triboelectric positive electrode material as the triboelectric positive electrode material, PTFE as the triboelectric negative electrode material, and is encapsulated by PVC to form a flexible wearable ANF / MXene-PTFE triboelectric nanosensor.

[0037] Example 1 Step 1: Prepare an aramid nanofiber dispersion with a concentration of 0.025% and an MXene dispersion with a concentration of 30 mg / mL. Step 2: Stir 1000 mL of the aramid nanofiber dispersion and 3 mL of the MXene dispersion at 30 °C for 25 min, mix them evenly, then perform vacuum filtration at a pressure of 0.10 Mpa for 3 h, and then dry at 100 °C for 12 min to obtain the ANF / MXene composite film. Step 3: Make the ANF / MXene composite film and a PTFE film with a thickness of 0.1 mm, a dynamic friction coefficient of 0.06, and a specific gravity of 2.1 g / cm 3 into the triboelectric positive and negative electrode materials respectively, and encapsulate the positive and negative electrodes with PVC tape to obtain the ANF / MXene-PTFE triboelectric nanogenerator device. In this example, for a flexible wearable sensing ANF / MXene-PTFE triboelectric nanogenerator device, the MXene percentage content is 26.5%, the tensile strength is 112.76 Mpa, and the triboelectric voltage is 58.19 V.

[0038] Figure 2 It is the SEM cross-sectional view of the ANF / MXene hybrid vacuum filtration film of the flexible wearable sensing ANF / MXene-PTFE triboelectric nanogenerator device of the present invention. It can be seen that the aramid nanofibers (ANF) and MXene nanosheets form a closely packed layered interface through molecular-level intercalation and compounding, presenting a uniform three-dimensional intertwined structure.

[0039] Figure 3This is the structural diagram of an ANF / MXene-PTFE triboelectric nanogenerator for flexible wearable sensing in the present invention. The ANF / MXene-PTFE triboelectric nanogenerator has a multi-layer composite structure. The middle layer is an ANF / MXene composite film as the positive electrode, PTFE as the negative electrode material, copper foil tape is pasted on the positive and negative electrodes, and then the positive and negative electrode materials are encapsulated with PVC tape.

[0040] Example 2 Step 1: Prepare an aramid nanofiber dispersion with a concentration of 0.025% and an MXene dispersion with a concentration of 35 mg / mL. Step 2: Stir 1000 mL of the aramid nanofiber dispersion and 3 mL of the MXene dispersion evenly at 30 °C for 30 min, then vacuum filter under a pressure of 0.10 Mpa for 3 h, and then dry at 100 °C for 13 min to prepare an ANF / MXene composite film. Step 3: Make the ANF / MXene composite film and a PTFE film with a thickness of 0.2 mm, a dynamic friction coefficient of 0.06, and a specific gravity of 2.2 g / cm 3 into the triboelectric positive and negative electrode materials respectively, and encapsulate the positive and negative electrodes with PVC tape to obtain an ANF / MXene-PTFE triboelectric nanogenerator.

[0041] For the ANF / MXene-PTFE triboelectric nanogenerator for flexible wearable sensing obtained in this example, the MXene percentage content is 29.6%, the tensile strength is 115.35 Mpa, and the triboelectric voltage is 76.77 V.

[0042] Example 3 Step 1: Prepare an aramid nanofiber dispersion with a concentration of 0.025% and an MXene dispersion with a concentration of 40 mg / mL. Step 2: Stir 1000 mL of the aramid nanofiber dispersion and 3 mL of the MXene dispersion evenly at 30 °C for 30 min, then vacuum filter under a pressure of 0.10 Mpa for 3 h, and then dry at 100 °C for 14 min to prepare an ANF / MXene composite film. Step 3: Make the ANF / MXene composite film and a PTFE film with a thickness of 0.2 mm, a dynamic friction coefficient of 0.08, and a specific gravity of 2.3 g / cm 3 into the triboelectric positive and negative electrode materials respectively, and encapsulate the positive and negative electrodes with PVC tape to obtain an ANF / MXene-PTFE triboelectric nanogenerator. The ANF / MXene-PTFE triboelectric nanogenerator for flexible wearable sensing obtained in this example has an MXene percentage content of 32.4%, a tensile strength of 121.59 Mpa, and a triboelectric voltage of 85.04 V.

[0043] Example 4 Step 1: Prepare an aramid nanofiber dispersion with a concentration of 0.025% and an MXene dispersion with a concentration of 40 mg / mL. Step 2: Stir 1100 mL of the aramid nanofiber dispersion and 4 mL of the MXene dispersion at 35 °C for 30 min until evenly mixed, then vacuum filter under a pressure of 0.10 Mpa for 3 h, and then dry at 105 °C for 15 min to prepare an ANF / MXene composite film. Step 3: Use the ANF / MXene composite film and a PTFE film with a thickness of 0.3 mm, a dynamic friction coefficient of 0.08, and a specific gravity of 2.3 g / cm 3 to make the triboelectric positive and negative electrode materials respectively, and encapsulate the positive and negative electrodes with PVC tape to obtain an ANF / MXene-PTFE triboelectric nanogenerator. The ANF / MXene-PTFE triboelectric nanogenerator for flexible wearable sensing obtained in this example has an MXene percentage content of 39.0%, a tensile strength of 114.34 Mpa, and a triboelectric voltage of 118.45 V.

[0044] Example 5 Step 1: Prepare an aramid nanofiber dispersion with a concentration of 0.025% and an MXene dispersion with a concentration of 40 mg / mL. Step 2: Stir 1200 mL of the aramid nanofiber dispersion and 5 mL of the MXene dispersion at 35 °C for 30 min until evenly mixed, then vacuum filter under a pressure of 0.10 Mpa for 3 h, and then dry at 105 °C for 15 min to prepare an ANF / MXene composite film. Step 3: Use the ANF / MXene composite film and a PTFE film with a thickness of 0.3 mm, a dynamic friction coefficient of 0.08, and a specific gravity of 2.3 g / cm 3 to make the triboelectric positive and negative electrode materials respectively, and encapsulate the positive and negative electrodes with PVC tape to obtain an ANF / MXene-PTFE triboelectric nanogenerator. The ANF / MXene-PTFE triboelectric nanogenerator for flexible wearable sensing obtained in this example has an MXene percentage content of 44.4%, a tensile strength of 108.29 Mpa, and a triboelectric voltage of 142.22 V.

[0045] Table 1 Technical parameters of the ANF / MXene-PTFE triboelectric nanogenerator devices obtained in Examples 1-5

[0046] When testing the triboelectric voltage, a prepared 2*2 cm square ANF / MXene-PTFE triboelectric nanogenerator device was selected. Under normal temperature and humidity conditions, a uniform contact pressure of 10 N was applied by a linear motor, and a Keithley 6514 electrometer was used to measure the triboelectric output voltage.

[0047] Table 1 shows the technical parameters of a flexible wearable sensing ANF / MXene-PTFE triboelectric nanogenerator device prepared in Examples 1-5. It can be seen that the triboelectric positive electrode material prepared by the preparation method provided by the present invention, benefiting from the application of ANF as the substrate material, has good mechanical properties, and its tensile strength is greater than 100 MPa. Refer to Figure 5 、 6 , as the content of MXene increases, the interlayer bonding of the three-dimensional intertwined structure is enhanced, and the tensile strength increases. However, as the content of MXene is higher, the proportion of the ANF substrate material decreases, and the mechanical properties decline. At the same time, the multi-level micro-nano grooves formed by the MXene sheets increase the effective contact area and form an efficient polarization electric pair with the PTFE film, significantly improving the charge density and output performance. A 4 cm 2 device can generate a voltage of 142.22 V. The triboelectric output performance is affected by the content of MXene nanosheets, and the higher the content, the better the triboelectric output performance.

[0048] The above are only the preferred embodiments of the present invention and are not used to limit the technical solutions of the present invention. Those skilled in the art should understand that without departing from the spirit and principles of the present invention, the technical solutions can be modified and replaced simply, and these modifications and replacements also fall within the protection scope covered by the claims.

Claims

1. A flexible wearable sensing ANF / MXene triboelectric cathode material, characterized in that: The following steps are involved: Step 1, preparing aramid nanofiber dispersion and MXene dispersion; Step 2: Evenly mix the aramid nanofiber dispersion and the MXene dispersion in proportion, form a composite film by vacuum filtration, and perform vacuum drying to obtain an ANF / MXene composite film.

2. The ANF / MXene triboelectric positive electrode material for flexible wearable sensing according to claim 1, characterized in that: In step 1, the aramid nanofiber mixed dispersion is prepared as follows: first, an alkaline solution, para-aramid fibers and dimethyl sulfoxide are stirred and mixed to obtain a dispersion A; wherein the mass ratio of the para-aramid fibers to the dimethyl sulfoxide is 1-2:400-500, the solute of the alkaline solution is potassium hydroxide, the concentration of the solute in the alkaline solution is 0.5-0.7 g / mL, and the ratio of the alkaline solution to the para-aramid fibers is 1-2 mL:1-2 g; The dispersion A is evenly dispersed in deionized water, and then filtered to obtain a para-aramid nanofiber dispersion B; wherein the volume ratio of water to the dispersion A is 80-100:1000-1200, and the concentration of the para-aramid nanofiber dispersion is 0.02%-0.03%.

3. The ANF / MXene tribo-positive electrode material for flexible wearable sensing according to claim 1, characterized in that: In step 1, the MXene aqueous dispersion is a nanosheet MXene aqueous dispersion prepared by an acid etching method, and the concentration of the MXene dispersion is 30-40 mg / mL.

4. The ANF / MXene tribo-positive electrode material for flexible wearable sensing according to claim 1, characterized in that: In step 2, the solution ratio of the aramid nanofiber dispersion and the MXene dispersion is 1000~1200mL:3~5mL, and the mixture is stirred at 25~35°C for 20~30min to be evenly mixed.

5. The ANF / MXene tribo-positive electrode material for flexible wearable sensing according to claim 1, characterized in that: In step 2, during vacuum filtration, the pressure is 0.08~0.10Mpa, the time is 2~3h, and the filtration membrane is a 0.02um mixed fiber filter membrane.

6. The ANF / MXene tribo-positive electrode material for flexible wearable sensing according to claim 1, characterized in that: In step 2, during the vacuum drying process, the temperature is 95-105° C. and the drying time is 12-15 min.

7. An ANF / MXene composite film obtained by the method for preparing the ANF / MXene friction positive electrode material for flexible wearable sensing as described in any one of claims 1 to 6.

8. A triboelectric nanoelectricity generating device, characterized in that: The device uses the ANF / MXene composite film as claimed in claim 7 as the friction positive electrode and PTFE as the friction negative electrode. The preparation method is: the ANF / MXene composite film and the PTFE film are pasted with copper foil tape and wires in a grid structure to form a positive electrode sheet and a negative electrode sheet respectively, and then packaged with PVC to form a flexible and wearable ANF / MXene-PTFE friction nano power generation device.

9. The triboelectric nanoelectricity device according to claim 8, characterized in that: The thickness of the PTFE membrane is 0.1~0.3mm, the dynamic friction coefficient is 0.06~0.08, and the specific gravity is 2.1~2.3g / cm 3 ; The thickness of copper foil tape is 0.04~0.06mm, and the thickness of PVC tape is 0.02~0.03mm.

10. A sensor, characterized in that: The sensor uses the ANF / MXene composite film as claimed in claim 7 as the friction positive electrode material and PTFE as the friction negative electrode material, and is encapsulated by PVC to form a flexible and wearable ANF / MXene-PTFE friction nanosensor.

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