A Ti3C2T x Fibres, methods for their preparation and use

Abstract

The application belongs to the technical field of flexible energy storage materials, and particularly relates to a Ti3C2T x fiber and a preparation method and application thereof. The Ti3C2T x fiber comprises Ti3C2T x nanosheets arranged in a liquid crystal orientation, the Ti3C2T x nanosheets are crosslinked through B-O covalent bonds, the fiber made of the Ti3C2T x nanosheets has high orientation, high density and low porosity, and has excellent electrical conductivity and mechanical strength.

Description

Technical Field

[0001] This invention belongs to the field of flexible energy storage materials technology, specifically relating to a Ti3C2T x Fibers, their preparation methods, and applications. Background Technology

[0002] In recent years, wearable electronic systems, as a new type of portable electronic device, have found wide applications in fields such as human-computer interaction, status monitoring, and healthcare. Conductive fibers, with their advantages of being lightweight, small in size, and highly intelligent, have become an indispensable basic component in wearable electronic systems. To date, many conductive materials, such as carbon-based materials (carbon fibers, carbon nanotubes, and graphene), conductive polymers (polyaniline, polypyrrole, and polythiophene), and metals (silver, copper, and stainless steel), have been used to prepare conductive fibers. However, these conductive fibers still suffer from limited conductivity and poor mechanical properties, making it difficult to meet the requirements of wearable electronic systems for high conductivity and excellent mechanical properties. Therefore, there is an urgent need to research and prepare new conductive fibers with excellent conductivity and mechanical properties.

[0003] Ti3C2T x As a novel two-dimensional transition metal carbide, Ti3C2T possesses excellent electrical conductivity (15000 S / cm) and superior mechanical properties (Young's modulus as high as 330 GPa), showing great potential in the construction of conductive fibers. In 2020, Zhang et al. discovered Ti3C2T. x The dispersion exhibits liquid crystal properties. Utilizing the pre-alignment characteristics of liquid crystals, Ti3C2T with high electrical conductivity (7748 S / cm) and good mechanical strength (40.5 MPa) was successfully prepared for the first time via wet spinning. x Fibers, thus beginning the development of Ti3C2T x Exploration of fibers. However, existing Ti3C2T... x The electrical conductivity and mechanical strength of the fiber are far lower than those of its constituent components, thus limiting the potential of Ti3C2T. x Applications and development of fibers. Summary of the Invention

[0004] In view of this, the object of the present invention is to provide a Ti3C2T x Fibers, their preparation methods, and applications; this Ti3C2T x Ti3C2T in fibers x Nanosheets have high orientation, high density and low porosity, and exhibit excellent electrical conductivity and mechanical strength.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] This invention provides a Ti3C2T xFibers, including Ti3C2T aligned with liquid crystal orientation x Nanosheets, the Ti3C2T x The nanosheets are cross-linked by BO covalent bonds.

[0007] Preferably, the Ti3C2T x Ti3C2T in fibers x The nanosheets have an orientation degree of 0.845–0.852, and the Ti3C2T x The fiber has a porosity of 18.81–20.25% and a density of 3.05–3.12 g / cm³. 3 The Ti3C2T x The mass percentage of boron in the fiber is 0.130–0.152%.

[0008] Preferably, the Ti3C2T x The fiber has an electrical conductivity of 7525–7781 S / cm, a tensile strength of 170.53–188.72 MPa, and a Young's modulus of 45.75–52.42 GPa.

[0009] The present invention also provides the Ti3C2T described in the above technical solution. x The method for preparing fibers includes the following steps:

[0010] Ti3C2T x The dispersion of nanosheets was wet-spun, and the resulting spun fibers were coagulated in a coagulation bath containing tetraborate to obtain Ti3C2T. x fiber.

[0011] Preferably, the coagulant containing tetraborate comprises tetraborate and an aqueous alcohol solution; the tetraborate is sodium tetraborate.

[0012] Preferably, the mass concentration of tetraborate in the coagulant containing tetraborate is 0.65 to 0.9 wt%.

[0013] Preferably, the Ti3C2T x Ti3C2T in the dispersion of nanosheets x The concentration of nanosheets is 20–30 mg / mL.

[0014] Preferably, the Ti3C2T x The preparation method of the nanosheets includes the following steps: mixing Ti3AlCl2 powder, LiF and hydrochloric acid, etching in an inert atmosphere, centrifuging and washing the etched mixture, dispersing the resulting precipitate in water and shaking, and then centrifuging the shaken mixture at a differential speed to obtain the Ti3C2T nanosheets. x Nanosheets.

[0015] Preferably, the mass ratio of Ti3AlCl2 powder to LiF is 1:1.5 to 5; and the molar ratio of LiF to HCl in hydrochloric acid is 1:2 to 6.

[0016] The present invention also provides the Ti3C2T described in the above technical solution. x Ti3C2T prepared by the fiber or the preparation method described in the above technical solution x Applications of fibers in wearable electronic systems.

[0017] This invention provides a Ti3C2T x Fibers, including Ti3C2T aligned with liquid crystal orientation x Nanosheets, the Ti3C2T x The nanosheets are cross-linked via BO covalent bonds. The strong covalent cross-linking of BO covalent bonds (borate ester covalent bonds) breaks and replaces the Ti3C2T bonds. x The electrostatic repulsion between the nanosheets makes Ti3C2T x The transformation from liquid crystal dispersion to macroscopic fibers enables Ti3C2T x The fiber possesses excellent mechanical properties and can be continuously extracted from the coagulation bath. The BO covalent bonds are relatively short and structurally stable, which not only reduces the size of the Ti3C2T fiber... x Ti3C2T inside the fiber x The spacing between the nanosheets also simultaneously improved Ti3C2T x The orientation and compactness of the nanosheets enabled the realization of Ti3C2T x Optimal load transfer between nanosheets significantly improves Ti3C2T x Mechanical properties of the fiber; Ti3C2T x The reduced spacing and closer stacking of nanosheets improve inter-sheet contact efficiency, which is beneficial for the development of Ti3C2T. x A continuous electron transport path is formed inside the fiber, allowing electrons to pass through Ti3C2T. x Nanosheets move in a more consistent and efficient manner, reducing electron scattering and improving the performance of Ti3C2T. x The electrical conductivity of nanofibers enables Ti3C2T x The fiber has high electrical conductivity and excellent mechanical properties.

[0018] The present invention also provides the above-mentioned Ti3C2T x Preparation method of fiber, Ti3C2T x Ti3C2T in liquid crystal dispersion x The nanosheets are locally oriented and not aggregated, which contributes to the formation of Ti3C2T x The dispersion was directly prepared by wet spinning of layer-aligned Ti3C2T without additives or polymers. xFibers. Furthermore, a coagulation bath containing tetraborate is used, utilizing the reaction between tetraborate and Ti3C2T. x The surface hydroxyl functional groups form strong covalent crosslinks of BO covalent bonds (boron ester covalent bonds), and the chemical crosslinking process breaks and replaces Ti3C2T. x The electrostatic repulsion between the nanosheets makes Ti3C2T x The transformation from liquid crystal dispersions to macroscopic fibers not only contributes to Ti3C2T x The continuous generation of fibers also enables Ti3C2T x The fiber has good mechanical properties and can be continuously removed from the coagulation bath. Attached Figure Description

[0019] Figure 1 The Ti3AlC2 and Ti3C2T in Example 1 x X-ray diffraction pattern (a) and X-ray photoelectron spectrum (b) of nanosheets;

[0020] Figure 2 Ti3C2T prepared in Example 1 x Polarized microscope image of nanosheets;

[0021] Figure 3 Ti3C2T prepared in Example 1 x Photos of fibers wound on bobbins and weaving;

[0022] Figure 4 Ti3C2T prepared in Example 1 x Scanning electron microscope image of the fiber;

[0023] Figure 5 Ti3C2T prepared in Example 1 x and Ti3C2T x Fourier transform infrared spectrum of the fiber;

[0024] Figure 6 Ti3C2T prepared for Example 1 and Comparative Examples 1-4 x Fiber density and porosity diagram;

[0025] Figure 7 Ti3C2T prepared for Example 1 and Comparative Examples 1-4 x Fiber orientation diagram. Detailed Implementation

[0026] This invention provides a Ti3C2T x Fibers, including Ti3C2T aligned with liquid crystal orientation x Nanosheets, the Ti3C2T x The nanosheets are cross-linked by BO covalent bonds.

[0027] Unless otherwise specified, the present invention does not have special requirements on the source of raw materials used, and commercially available products well known to those skilled in the art can be used.

[0028] As one implementation method, the Ti3C2T x Ti3C2T in fibers x The orientation degree of the nanosheets is 0.845–0.852, specifically 0.852 in this embodiment; the Ti3C2T x The fiber has a porosity of 18.81%–20.25%, specifically 18.81% in this embodiment, and a density of 3.05–3.12 g / cm³. 3 In the specific embodiment, it is 3.12 g / cm³. 3 The diameter is 22-24 μm, and in the specific embodiment it is 23 μm; the Ti3C2T x The mass percentage of B in the fiber is 0.130–0.152%, and in the specific embodiment it is 0.142%.

[0029] As one implementation method, the Ti3C2T x The electrical conductivity of the fiber is 7525–7781 S / cm, with 7781 S / cm in the specific embodiment; the tensile strength is 170.53–188.72 MPa, with 188.72 MPa in the specific embodiment; and the Young's modulus is 45.75–52.42 GPa, with 52.42 GPa in the specific embodiment.

[0030] The present invention also provides the Ti3C2T described in the above technical solution. x The method for preparing fibers includes the following steps:

[0031] Ti3C2T x The dispersion of nanosheets was wet-spun, and the resulting spun fibers were coagulated in a coagulation bath containing tetraborate to obtain Ti3C2T. x fiber.

[0032] This invention uses Ti3C2T x The dispersion of nanosheets is wet-spun to obtain spun fibers.

[0033] The Ti3C2T of the present invention x T in nanosheets x These represent various surface functional groups on nanosheets, such as -OH and -F.

[0034] As one implementation method, the Ti3C2T xThe preparation method of the nanosheets includes the following steps: mixing Ti3AlCl2 powder, LiF and hydrochloric acid, etching in an inert atmosphere, centrifuging and washing the etched mixture, dispersing the resulting precipitate in water and shaking, and then centrifuging the shaken mixture at a differential speed to obtain the Ti3C2T nanosheets. x Nanosheets.

[0035] In one embodiment, the particle size of the Ti3AlCl2 powder is 1–40 μm, specifically 5–20 μm; the mass ratio of Ti3AlCl2 powder to LiF is 1:1.5–5, specifically 1:1.6–3; the molar ratio of LiF to HCl in hydrochloric acid is 1:2–6, specifically 1:2.9–4.9; the concentration of hydrochloric acid is 6–9 mol / L, specifically 7–9 mol / L; the inert atmosphere is argon; after purging argon into the dispersion obtained by mixing Ti3AlCl2 powder, LiF, and hydrochloric acid, the container is sealed with plastic wrap; the etching is performed under stirring conditions; the stirring rate is 500–1000 rpm, specifically 800–1000 rpm; the etching temperature is 40–50°C, specifically 50°C; and the etching time is 36–48 h, specifically 48 h.

[0036] In one embodiment, the Ti3AlCl2 powder, LiF, and hydrochloric acid are mixed as follows: LiF is first added to hydrochloric acid and stirred until completely dissolved, and then Ti3AlCl2 powder is added; the stirring speed is 500-1000 rpm, and in a specific embodiment it is 800-1000 rpm; the stirring time is 20-30 min, and in a specific embodiment it is 30 min; the Ti3AlCl2 powder is added slowly in multiple batches.

[0037] During the etching process, HF etching is the main process. LiF and HCl first generate HF, which then etches the Al layer of the Ti3AlC2 phase to generate Ti3C2 and H2. Since Ti3C2 is not stable, it will continue to combine with H2O and HF to generate Ti3C2(OH)2 and Ti3C2F2, while releasing H2.

[0038] The reaction equations involved in the etching process are as follows:

[0039] Ti3AlC2+3HF→AlF3+3 / 2H2+Ti3C2

[0040] Ti3C2 + 2H2O → Ti3C2(OH)2 + H2

[0041] Ti3C2 + 2HF → Ti3C2F2 + H2.

[0042] This invention utilizes HF generated from the reaction of LiF and HCl to etch Ti3AlCl2, thereby preparing Ti3C2T. x The nanosheet method is milder and more environmentally friendly than directly etching Ti3AlCl2 with HF.

[0043] In one embodiment, the centrifugal washing process results in a neutral washing waste liquid; the reagent used for centrifugal washing is water, specifically deionized water in this embodiment; the number of centrifugal washing cycles is 7-9 times, specifically 8 times in this embodiment; the centrifugation rate for each centrifugal washing cycle is 3500-5000 rpm, specifically 3500-4000 rpm in this embodiment; the duration of each centrifugal washing cycle is 5-10 minutes, specifically 5-8 minutes in this embodiment; neutrality is defined as pH = 7; the water is deionized water; the present invention does not specifically limit the oscillation method, and any oscillation method well known in the art can be used. In this embodiment of the present invention, the oscillation... The centrifugation is performed by hand-cranking; the oscillation time is 15-25 minutes, specifically 20 minutes in this embodiment; the differential centrifugation involves first performing low-speed centrifugation, then centrifuging the supernatant obtained from the low-speed centrifugation at high speed; the low-speed centrifugation rate is 1000-1500 rpm, specifically 1500 rpm in this embodiment; the low-speed centrifugation time is 30-40 minutes, specifically 30 minutes in this embodiment; the high-speed centrifugation rate is 4500-5000 rpm, specifically 4500 rpm in this embodiment; the high-speed centrifugation time is 10-20 minutes, specifically 20 minutes in this embodiment; the Ti3C2T x The nanosheets are stored in an inert atmosphere and at a low temperature to prevent oxidation; the inert atmosphere is argon; and the low temperature is 0°C.

[0044] This invention prepares Ti3C2T with a certain size using a "LiF / HCl etching-differential centrifugation" method. x Nanosheets, and then Ti3C2T x The dispersion of nanosheets is used for spinning. In this invention, the mixture obtained after etching contains broken Ti3C2T. x Nanosheets, the required Ti3C2T x This invention uses nanosheets and unetched or incompletely etched Ti3AlCl2 to obtain the desired Ti3C2T by differential centrifugation. x Nanosheets.

[0045] As one implementation method, the Ti3C2T x The preparation method of the dispersion of nanosheets is as follows: Ti3C2T x Nanosheets were dispersed in water to obtain the Ti3C2T. xA dispersion of nanosheets; the water is deionized water.

[0046] As one implementation method, the Ti3C2T x Ti3C2T in the dispersion of nanosheets x The concentration of the nanosheets is 20–30 mg / mL, and in the specific example it is 25 mg / mL.

[0047] In one embodiment, the equipment used for wet spinning includes a syringe with a nozzle and an injection pump; the inner diameter of the syringe nozzle is 200 μm; and the injection pump has a push rate of 3.6 mL / h.

[0048] Before the wet spinning process, the present invention further includes: [the process of spinning the Ti3C2T...] x After the dispersion of nanosheets is placed in a syringe with a nozzle, it is emptied; the emptying is performed by using the syringe plunger to expel the Ti3C2T from the syringe. x The dispersion of nanosheets is slightly squeezed out of the nozzle, expelling air from the syringe. This invention is applicable to syringes containing Ti3C2T. x The syringe is emptied of the nanosheet dispersion to prevent the fibers from breaking due to the presence of air during extrusion.

[0049] After obtaining the spun fibers, the present invention coagulates the spun fibers in a coagulation bath containing tetraborate to obtain Ti3C2T. x fiber.

[0050] In one embodiment, the coagulant containing tetraborate comprises tetraborate and an aqueous alcohol solution; the tetraborate is sodium tetraborate; the aqueous alcohol solution comprises water and ethanol; the water is deionized water; the mass ratio of water to ethanol is 7:3; the preparation method of the coagulant containing tetraborate includes the following steps: mixing tetraborate and water and stirring until dissolved, then adding ethanol; the stirring speed is 500-1000 rpm, specifically 800-1000 rpm in this embodiment. The sodium tetraborate material used in this invention is widely available and low in cost.

[0051] In one embodiment, the mass concentration of tetraborate in the coagulated solution containing tetraborate is 0.65 to 0.9 wt%, and in a specific embodiment it is 0.75 wt%.

[0052] In one embodiment, the coagulation bath coagulation is carried out under rotating conditions; the rotation speed is 9.42 mm / s; the rotating device is a rotary table; during the rotation process, the container holding the coagulated solution containing tetraborate is placed in the center of the rotary table to ensure that Ti3C2T is used during spinning. xThe fibers are subjected to uniform stress; after the wet spinning process is completed, the present invention further includes: slowly reducing the rotation speed to avoid excessively rapid reduction of the rotation speed leading to Ti3C2T x The fibers become entangled and difficult to collect; the rotation speed is gradually reduced to 0.1 mm / s. 2 The rotational speed is reduced. At the aforementioned rotational speed, the spun fibers can be spun continuously without breaking.

[0053] In one embodiment, after coagulation in the coagulation bath, the process further includes: immersing the coagulated spun fibers in the tetraborate-containing coagulation solution, followed by solid-liquid separation; the resulting solid is then washed, collected, and dried sequentially to obtain Ti3C2T. x The fiber; the soaking time is 10-20 min, specifically 10-15 min in this embodiment; the washing frequency is 2-5 times, specifically 3 times in this embodiment; the washing solution used is an alcohol-water solution; the alcohol-water solution includes water and ethanol; the water is deionized water; the mass ratio of water to ethanol is 7:3; the collection is done by drum collection; the drying is carried out at room temperature, specifically 25°C in this embodiment; the drying time is 20-40 min, specifically 30 min in this embodiment; the drying is carried out in air; the Ti3C2T x The fibers are stored under vacuum conditions to prevent oxidation.

[0054] This invention involves further immersing the spun fibers, after coagulation in the coagulation bath, in the tetraborate-containing coagulant solution to allow the tetraborate to better react with Ti3C2T. x Hydroxyl group reaction on nanosheets.

[0055] This invention modulates Ti3C2T x The concentration of the dispersion of nanosheets affects the Ti3C2T x The nanosheets are locally oriented and not aggregated, which contributes to the formation of Ti3C2T x Nanosheets of Ti3C2T with aligned layers were prepared directly by wet spinning without additives or polymers. x Fibers. Then, Ti3C2T... x A dispersion of nanosheets was used as the spinning solution, and a coagulation bath containing tetraborate was used as the coagulation bath. A continuous and controllable wet spinning process was employed to prepare Ti3C2T nanosheets with high electrical conductivity and excellent mechanical properties. x Fibers. Tetraborate and Ti3C2T during wet spinning. x The hydroxyl groups on the surface form stable BO covalent bonds (boronate covalent bonds), and this chemical crosslinking process breaks and replaces the Ti3C2T bonds. x The electrostatic repulsion between the nanosheets makes Ti3C2T xThe transformation from liquid crystal dispersions to macroscopic fibers not only contributes to Ti3C2T x The continuous formation of gel fibers also enables Ti3C2T x The gel fibers possess excellent mechanical properties and can be continuously removed from the coagulation bath. Furthermore, this strong covalent cross-linking also reduces the size of the Ti3C2T... x Ti3C2T inside the fiber x Nanosheet spacing was simultaneously improved in Ti3C2T x The orientation and compactness of the nanosheets significantly enhance the Ti3C2T x Inter-chip load transfer significantly improves Ti3C2T x The mechanical properties of the fiber also contribute to the formation of continuous electron transport paths within the fiber, enabling electrons to move more consistently and efficiently between sheets, reducing electron scattering, and improving fiber conductivity.

[0056] The present invention also provides the Ti3C2T described in the above technical solution. x Ti3C2T prepared by the fiber or the preparation method described in the above technical solution x Applications of fibers in wearable electronic systems.

[0057] This invention relates to the Ti3C2T x There are no special limitations on how fibers are used in wearable electronic systems; any application method known in the field can be used.

[0058] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, but they should not be construed as limiting the scope of protection of the present invention.

[0059] Example 1

[0060] 1.6 g LiF was added to 20 mL of 9 mol / L hydrochloric acid and stirred at 1000 rpm for 30 min until completely dissolved. Then, 1.0 g Ti3AlCl2 powder (particle size 1–40 μm) was slowly added in multiple batches. Argon gas was bubbled into the resulting dispersion, and the container was sealed with plastic wrap. Etching was performed at 50 °C and stirred at 800 rpm for 48 h under an argon atmosphere. After the reaction, the mixture was repeatedly centrifuged and washed 8 times with deionized water until the pH of the washing solution reached 7, centrifuging at 3500 rpm for 5 min each time. The resulting deposit was dispersed in deionized water and continuously shaken for 20 min. Then, the shaken mixture was centrifuged at 1500 rpm for 30 min, and the supernatant was collected and centrifuged at 4500 rpm for 20 min to obtain Ti3C2T. x Nanosheets;

[0061] Sodium tetraborate (Na2B4O7) and deionized water were mixed and stirred at 1000 rpm until dissolved. Then ethanol was added to obtain a coagulant containing tetraborate. The mass concentration of sodium tetraborate in the coagulant containing tetraborate was 0.75%, and the mass ratio of deionized water to ethanol was 7:3.

[0062] The Ti3C2T x Nanosheets were dispersed in deionized water to obtain Ti3C2T with a concentration of 25 mg / mL. x A dispersion of nanosheets was prepared and used as a spinning solution in a syringe with a nozzle having an inner diameter of 200 μm. The Ti3C2T nanosheets in the syringe were then spun using the syringe plunger. x The dispersion of nanosheets was slightly squeezed out of the nozzle to expel air from the syringe. The injection pump was set to a flow rate of 3.6 mL / h to inject Ti3C2T. x The nanosheet dispersion is extruded through a nozzle into a coagulation bath containing tetraborate for coagulation. A container holding the tetraborate-containing coagulation solution is placed in the center of a rotating disk and rotated at 9.42 mm / s. The spun fibers form immediately upon contact with the tetraborate-containing coagulation solution and continue to be produced as the spinning process continues. After wet spinning is completed, the fibers are spun at a speed of 0.1 mm / s. 2 The rotation speed was reduced, and the coagulated spun fibers were immersed in the tetraborate-containing coagulation solution for 10 minutes. Solid-liquid separation was then performed. The obtained solid was washed three times with a washing solution of deionized water and ethanol in a 7:3 mass ratio. The washed spun fibers were collected on a drum and dried in air at 25°C for 30 minutes to obtain Ti3C2T. x fiber.

[0063] Example 2

[0064] The difference from Example 1 is that the Ti3C2T prepared in Example 1 is used instead of the Ti3C2T. x The spun fibers obtained by wet spinning the dispersion of nanosheets were coagulated in a coagulation bath containing tetraborate with a sodium tetraborate mass concentration of 0.65%, and the rest of the process was the same as in Example 1.

[0065] Example 3

[0066] The difference from Example 1 is that the Ti3C2T prepared in Example 1 is used instead of the Ti3C2T. x The spun fibers obtained by wet spinning the dispersion of nanosheets were coagulated in a coagulation bath containing tetraborate with a sodium tetraborate mass concentration of 0.9%, and the rest of the process was the same as in Example 1.

[0067] Comparative Example 1

[0068] The difference from Example 1 is that the Ti3C2T prepared in Example 1 is used instead of the Ti3C2T. xThe spun fibers obtained by wet spinning the dispersion of nanosheets were coagulated in a coagulation bath containing tetraborate with a sodium tetraborate mass concentration of 0.25%, and the rest of the process was the same as in Example 1.

[0069] Comparative Example 2

[0070] The difference from Example 1 is that the Ti3C2T prepared in Example 1 is used instead of the Ti3C2T. x The spun fibers obtained by wet spinning the dispersion of nanosheets were coagulated in a coagulation bath containing tetraborate with a mass concentration of 0.5% sodium tetraborate. The rest of the process was the same as in Example 1.

[0071] Comparative Example 3

[0072] The difference from Example 1 is that the Ti3C2T prepared in Example 1 is used instead of the Ti3C2T. x The spun fibers obtained by wet spinning the dispersion of nanosheets were coagulated in a coagulation bath containing tetraborate with a mass concentration of 1% sodium tetraborate. The rest of the process was the same as in Example 1.

[0073] Comparative Example 4

[0074] The difference from Example 1 is that the Ti3C2T prepared in Example 1 is used instead of the Ti3C2T. x The spun fibers obtained by wet spinning the dispersion of nanosheets were coagulated in a coagulation bath containing tetraborate with a sodium tetraborate mass concentration of 1.25%, and the rest of the process was the same as in Example 1.

[0075] Comparative Example 5

[0076] The difference from Example 1 is that the Ti3C2T prepared in Example 1 is used instead of the Ti3C2T. x The spun fibers obtained by wet spinning the nanosheet dispersion were coagulated in a coagulation bath of a tetraborate-containing coagulant solution with a sodium tetraborate mass concentration of 0%, and the rest of the process was the same as in Example 1. Ti3C2T could not be formed. x Fibers cannot be removed from the coagulation bath and dried to obtain Ti3C2T. x fiber.

[0077] Performance testing

[0078] (1) The Ti3C2T prepared in Example 1 and Comparative Examples 1-4 x The properties of the fiber were tested, and the results are shown in Figure 1.

[0079] Table 1. Ti3C2T prepared in Example 1 and Comparative Examples 1-4 x Fiber performance test results

[0080] project Electrical conductivity (S / cm) Tensile strength (MPa) Young's modulus (GPa) Example 1 7781 188.72 52.42 Comparative Example 1 6407 74.40 16.91 Comparative Example 2 7206.67 130.31 31.78 Comparative Example 3 7340 139.83 43.7 Comparative Example 4 6644 95.52 32.94

[0081] As shown in Table 1, the Ti3C2T prepared in the embodiments of the present invention... x The electrical conductivity, tensile strength, and Young's modulus of the fiber were significantly higher than those of the comparative example, indicating that the tetraborate content in the coagulant containing tetraborate affects the Ti3C2T content. x The number of BO covalent bonds in the fiber affects Ti3C2T. x Ti3C2T in fibers x The orientation and compactness of nanosheets affect their electrical conductivity and mechanical properties.

[0082] (2) Figure 1 The Ti3AlC2 and Ti3C2T in Example 1 x X-ray diffraction pattern (a) and X-ray photoelectron spectrum (b) of the nanosheets.

[0083] Depend on Figure 1 As shown in (a), the two main characteristic peaks of Ti3AlC2 are located at 9.46° and 38.7°, corresponding to the (002) and (104) crystal planes of Ti3AlC2, respectively. After etching with strong acid, Ti3C2T x The (104) peak of Ti3AlC2 disappeared, and the (002) peak shifted from 9.46° to 7.48°, confirming that the Al layer was successfully etched. Furthermore, the values ​​of Ti3AlC2 and Ti3C2T calculated according to Bragg's formula... x The interlayer spacings are 1.08 nm and 1.3 nm, respectively, indicating that Li + The intercalation of ions increases the efficiency of Ti3C2T x The interlayer spacing.

[0084] from Figure 1 As shown in (b), characteristic absorption peaks for Ti 3p, Ti 3s, Al 2p, Al 2s, C 1s, Ti 2p, and O 1s are present in Ti3AlC2 at 35 eV, 60 eV, 74 eV, 119 eV, 285 eV, 457 eV, and 531 eV, respectively, indicating that Ti3AlC2 mainly contains four atoms: Ti, Al, C, and O. After etching with strong acid, Ti3C2T x The Al 2p and Al 2s peaks disappeared significantly, and a characteristic F1s absorption peak appeared at 685 eV, indicating that Ti3C2T x It mainly contains four types of atoms: Ti, C, O, and F.

[0085] (3) Figure 2 Ti3C2T prepared in Example 1 x Polarized microscope image of nanosheets.

[0086] Depend on Figure 2 It can be seen that Ti3C2Tx The birefringence phenomenon in the dispersion formed by the nanosheets is very obvious and uniform, indicating that Ti3C2T x The dispersion completely changed from isotropic to anisotropic, Ti3C2T x The internal local orientation and lack of aggregation are evident in the assembly of Ti3C2T. x In terms of macroscopic architecture, especially in the preparation of layer-aligned Ti3C2T by wet spinning x It has unique advantages in terms of fibers.

[0087] (3) Figure 3 Ti3C2T prepared in Example 1 x Photographs of fibers wound on a bobbin and weaving, wherein (a) is Ti3C2T. x Photographs of fibers wound on a bobbin, (b) and (c) for Ti3C2T. x Photographs of fiber weaving.

[0088] Depend on Figure 3 As can be seen in (a), Ti3C2T x The fibers can be produced continuously and are of uniform size.

[0089] Depend on Figure 3 As can be seen from (b) and (c), Ti3C2T x The fiber has good mechanical properties and can be manually woven into textiles.

[0090] (4) Figure 4 Ti3C2T prepared in Example 1 x Scanning electron microscope images of fibers, where (a) is Ti3C2T. x Whole-scale scanning electron microscope image of the fiber, (b) is Ti3C2T x Cross-sectional scanning electron microscope image of the fiber, (c) is Ti3C2T x Scanning electron microscope image of the fiber surface.

[0091] Depend on Figure 4 As can be seen in (a), Ti3C2T x The average diameter of the fiber is 23 μm.

[0092] Depend on Figure 4 As can be seen in (b), Ti3C2T in the fiber x The nanosheets are arranged and densely packed along the fiber axis, indicating locally ordered Ti3C2T during the wet spinning process. x The nanosheets are aligned and arranged under the shearing action of the fine nozzle and the interfacial cross-linking action.

[0093] Depend on Figure 4As can be seen in (c), during the drying process, due to Ti3C2T x The shrinkage of the fibers gives them a wrinkled surface morphology.

[0094] (5) Figure 5 Ti3C2T prepared in Example 1 x and Ti3C2T x Fourier transform infrared spectrum of the fiber.

[0095] Depend on Figure 5 It can be seen that Ti3C2T x At 3426cm -1 and 1663cm -1 The characteristic peaks are attributed to the typical tensile vibrations of -OH and C=O. Meanwhile, Ti3C2T... x In the fiber at 3426cm -1 The decrease in the intensity of the -OH peak at 1168 cm⁻¹ -1 The appearance of the BO characteristic peak further proves that Ti3C2T x Ti3C2T in fibers x The nanosheets are covalently cross-linked through borate ester covalent bonds (BO covalent bonds).

[0096] (6) Figure 6 Ti3C2T prepared for Example 1 and Comparative Examples 1-4 x Fiber density and porosity diagram.

[0097] Depend on Figure 6 It can be seen that when the Na2B4O7 concentration increases from 0.25wt% to 0.75wt%, Ti3C2T x The porosity of the fiber decreased significantly from 34.27±2.98% to 18.81±1.82%, and the density decreased from 2.43±0.11 g / cm³. 3 Increased to 3.12±0.07 g / cm³ 3 More than 0.75 wt% Na₂B₄O₇ may lead to Ti₃C₂T x The increased wrinkles and inter-sheet gaps in nanosheets lead to increased fiber porosity and decreased fiber density.

[0098] (7) Figure 7 Ti3C2T prepared for Example 1 and Comparative Examples 1-4 x Fiber orientation diagram.

[0099] Depend on Figure 7 It can be seen that as the Na₂B₄O₇ concentration increases from 0.25 wt% to 0.75 wt%, the orientation degree increases from 0.815 to 0.852. This indicates that Ti₃C₂T xThe stable boron-oxygen tetrahedral structure formed between the lamellae can effectively improve the fiber lamellar arrangement and promote lamellar high orientation. However, as the Na₂B₄O₇ concentration further increases to 1.25 wt%, the Ti₃C₂T x The full width at half height (FWHM) of the fiber widened, and the orientation degree decreased from 0.852 to 0.822. This indicates that excessive borate ester covalent bonds (BO covalent bonds) are detrimental to the effective alignment of nanosheets in the fiber.

[0100] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention and not all embodiments. People can obtain other embodiments based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A Ti3C2T x Fiber, characterized in that, Including Ti3C2T aligned with liquid crystal orientation x Nanosheets, the Ti3C2T x Nanosheets are cross-linked via BO covalent bonds; The Ti3C2T x Ti3C2T in fibers x The nanosheets have an orientation degree of 0.845~0.852, and the Ti3C2T x The fiber has a porosity of 18.81–20.25% and a density of 3.05–3.12 g / cm³. 3 The Ti3C2T x The mass percentage of boron in the fiber is 0.130~0.152%; The Ti3C2T x The fiber has an electrical conductivity of 7525~7781 S / cm, a tensile strength of 170.53~188.72 MPa, and a Young's modulus of 45.75~52.42 GPa; The Ti3C2T x The fiber preparation method includes the following steps: Ti3C2T x The dispersion of nanosheets was wet-spun, and the resulting spun fibers were coagulated in a coagulation bath containing tetraborate to obtain Ti3C2T. x fiber; The coagulant containing tetraborate comprises tetraborate and an aqueous alcohol solution; the tetraborate is sodium tetraborate; the aqueous alcohol solution comprises water and ethanol; The tetraborate concentration in the coagulated solution containing tetraborate is 0.65~0.9wt%.

2. The Ti3C2T as described in claim 1 x A method for preparing fibers, characterized in that, Includes the following steps: Ti3C2T x The dispersion of nanosheets was wet-spun, and the resulting spun fibers were coagulated in a coagulation bath containing tetraborate to obtain Ti3C2T. x fiber; The coagulant containing tetraborate comprises tetraborate and an aqueous alcohol solution; the tetraborate is sodium tetraborate; the aqueous alcohol solution comprises water and ethanol; The tetraborate concentration in the coagulated solution containing tetraborate is 0.65~0.9wt%.

3. The preparation method according to claim 2, characterized in that, The Ti3C2T x Ti3C2T in the dispersion of nanosheets x The concentration of nanosheets is 20~30 mg / mL.

4. The preparation method according to claim 2 or 3, characterized in that, The Ti3C2T x The preparation method of the nanosheets includes the following steps: mixing Ti3AlCl2 powder, LiF and hydrochloric acid, etching in an inert atmosphere, centrifuging and washing the etched mixture, dispersing the resulting precipitate in water and shaking, and then centrifuging the shaken mixture at a differential speed to obtain the Ti3C2T nanosheets. x Nanosheets.

5. The preparation method according to claim 4, characterized in that, The mass ratio of Ti3AlCl2 powder to LiF is 1:1.5~5; the molar ratio of LiF to HCl in hydrochloric acid is 1:2~6.

6. The Ti3C2T as described in claim 1 x Fibers or Ti3C2T prepared by the preparation method according to any one of claims 2 to 5 x Applications of fibers in wearable electronic systems.

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