MXene composite fiber electrode with synaptic channels and its preparation method

Abstract

This invention discloses an MXene composite fiber electrode with synaptic channels and its preparation method. Specifically, titanium carbide MXene powder and oxidized nanocellulose aqueous dispersion are mixed at a mass ratio of 5:5 to 9:1. Then, poly(3,4-ethylenedioxythiophene):polystyrene sulfonate is added at a total solid content of 8wt% to 16wt% to form a conductive polymer dispersion. The total solid content is controlled at 2wt% to 4wt%. After stirring, the mixture is allowed to stand to remove bubbles, resulting in a composite spinning solution. The composite spinning solution is then injected into an anhydrous ethanol or an 80% to 90% ethanol aqueous solution coagulation bath through a wet spinning device at a feed rate of 6mL / h to 12mL / h. The solution coagulates to form continuous fibers, which are then dried to obtain the MXene-based composite fiber electrode. This invention solves the problems of discontinuous interlayer contact, insufficient interfacial electrotransmission, and high resistance that limit the electrochemical performance of existing MXene-based fiber electrodes.

Description

Technical Field

[0001] This invention belongs to the interdisciplinary field of flexible energy storage materials and textile engineering, specifically relating to MXene composite fiber electrodes with synaptic channels and their preparation methods. Background Technology

[0002] Currently, materials represented by two-dimensional transition metal carbonitrides (MXenes) show great promise for application in flexible fibrous energy storage devices due to their excellent conductivity and high specific capacitance. Existing research typically incorporates high aspect ratio cellulose nanofibers (CNFs) or oxidized cellulose nanofibers (TOCNFs) as a three-dimensional framework, combining them with MXenes through wet spinning to address the problems of easy agglomeration, brittleness, and insufficient fiber structure stability in pure MXene nanosheets during continuous spinning.

[0003] However, the following obvious drawbacks still exist: First, the cellulose nanofiber itself is an insulator, which introduces a large number of weak electrical transport regions at the interface between the MXene sheets and the framework, thereby blocking the continuous transport path of electrons; Second, the electron transport inside the fiber relies excessively on the local contact between the MXene sheets, which generates a large additional contact resistance at the contact nodes, which seriously limits the long-range conductivity of the composite fiber and its electrochemical performance at high current densities. Summary of the Invention

[0004] The purpose of this invention is to provide an MXene composite fiber electrode with synaptic channels, which solves the problems that limit the electrochemical performance of existing MXene-based fiber electrodes due to discontinuous interlayer contact, insufficient interfacial electrotransmission, and high resistance.

[0005] Another object of the present invention is to provide a method for preparing an MXene composite fiber electrode with synaptic channels.

[0006] The first technical solution adopted in this invention is a method for preparing MXene composite fiber electrodes with synaptic channels. Titanium carbide MXene powder and oxidized nanocellulose aqueous dispersion are mixed at a mass ratio of 5:5-9:1. Then, poly(3,4-ethylenedioxythiophene):polystyrene sulfonate with a total solid content of 8wt%-16wt% is added to form a conductive polymer dispersion. The total solid content is controlled at 2wt%-4wt%. After stirring, the mixture is allowed to stand to remove bubbles, resulting in a composite spinning solution. The composite spinning solution is then injected into anhydrous ethanol or an 80%-90% ethanol aqueous solution coagulation bath using a wet spinning device at a feed rate of 6mL / h-12mL / h. The mixture coagulates to form continuous fibers, which are then dried to obtain the MXene-based composite fiber electrode.

[0007] The first technical solution of the present invention is further characterized by including the following steps: Step 1: Select titanium carbide MXene powder and oxidized nanocellulose aqueous dispersion with a mass ratio of 5:5-9:1; Step 2: Add titanium carbide MXene powder to deionized water and stir until homogeneous to obtain titanium carbide MXene aqueous dispersion; Step 3: After adding the weighed oxidized nanocellulose aqueous dispersion to the titanium carbide MXene aqueous dispersion and stirring evenly, based on the total solid content of titanium carbide MXene and oxidized nanocellulose, add poly(3,4-ethylenedioxythiophene):polystyrene sulfonate dispersion to form a conductive polymer dispersion. The solid content of the poly(3,4-ethylenedioxythiophene):polystyrene sulfonate dispersion is 8wt%-16wt% of the total solid content of titanium carbide MXene and oxidized nanocellulose; the total solid content of the conductive polymer dispersion is 2wt%-4wt%. Step 4: Stir the conductive polymer dispersion at 800-1500 rpm for 10-24 hours at 20℃-30℃ to obtain the composite spinning solution; Step 5: Let the composite spinning solution stand for 0.5h-2h to achieve defoaming. After defoaming, the composite spinning solution is loaded into an injection device or a continuous wet spinning device and injected into the coagulation bath through an 18G-21G injection needle at a propulsion rate of 6mL / h-12mL / h. Step 6: After the composite spinning solution enters the coagulation bath, solvent exchange and coagulation occur to form continuous composite fibers. Step 7: Take out the solidified continuous composite fiber and dry it by laying it flat or hanging it at 20℃-40℃ for 10min-20min to obtain the MXene-based composite fiber electrode.

[0008] In step 1, the oxidized nanocellulose is oxidized nanocellulose with carboxyl groups on its surface; the diameter is 3nm-100nm, the length is 0.5μm-10μm, the aspect ratio is not less than 50, and the carboxyl content is 0.5mmol / g-2.0mmol / g. The solid content of the oxidized nanocellulose aqueous dispersion is 1.0wt%-3.0wt%.

[0009] The solid content in the poly(3,4-ethylenedioxythiophene):polystyrene sulfonate dispersion is 0.8wt%-2.0wt%.

[0010] Titanium carbide MXene powder was prepared by treating titanium aluminide MAX phase powder with a lithium fluoride / hydrochloric acid etching system. The preparation process is as follows: Step 1.1: Add lithium fluoride to an 8 mol / L-10 mol / L hydrochloric acid solution and stir at 35℃-45℃ for 5 min-10 min to obtain a lithium fluoride / hydrochloric acid etching system; Step 1.2: Add titanium aluminide MAX phase powder to the lithium fluoride / hydrochloric acid etching system and etch by stirring and reacting in a water bath at 35℃-45℃ for 24h-36h. Step 1.3: Centrifuge the etched suspension at a speed of 3000-5000 rpm for 3-10 minutes until the pH of the supernatant is 5-7. Step 1.4: The washed precipitate is redispersed in deionized water, and after vacuum filtration for 5 min-10 min, ultrasonic exfoliation in an ice-water bath for 0.5 h-1.0 h, and freeze drying for 36 h-48 h, titanium carbide MXene powder is obtained.

[0011] The mass ratio of lithium fluoride to titanium aluminide MAX phase powder is 0.5:1-2:1.

[0012] Titanium carbide MXene has –O, –OH and / or –F end groups on its surface.

[0013] In step 5, the coagulation bath should be anhydrous ethanol or an aqueous solution of ethanol with a concentration of 80%-90%.

[0014] After drying, the continuous composite fiber is oxidized into a continuous fiber skeleton of cellulose nanoparticles, and titanium carbide MXene sheets are distributed in the fiber skeleton of oxidized cellulose nanoparticles. Poly(3,4-ethylenedioxythiophene): Polystyrene sulfonate is distributed between titanium carbide MXene, at the edge region of titanium carbide MXene, at the interface between titanium carbide MXene and oxidized nanocellulose, or in the multiphase contact region inside the composite fiber.

[0015] The second technical solution adopted in this invention is an MXene composite fiber electrode with synaptic channels, wherein the MXene-based composite fiber electrode is prepared by the above-mentioned preparation method; The MXene-based composite fiber electrode has a continuous fibrous structure, and the titanium carbide MXene sheets are distributed in an overlapping, stacked and / or networked manner in the composite fiber electrode.

[0016] The beneficial effects of this invention are: (1) In this invention, poly(3,4-ethylenedioxythiophene):polystyrene sulfonate is introduced as a conductive bridging phase into a composite fiber system composed of two-dimensional transition metal carbides and oxidized nanocellulose. This conductive polymer is distributed between the titanium carbide MXene sheets and at the interface between titanium carbide MXene and the oxidized nanocellulose skeleton. By filling the interface defects and interlayer gaps, a continuous charge transport channel similar to a nerve synapse is constructed. This structure can effectively reduce the interfacial contact resistance caused by the insulation of oxidized nanocellulose itself and the discontinuity of multiphase interface contact, thereby endowing the composite fiber with good long-range conductivity.

[0017] (2) This invention uses oxidized nanocellulose as a three-dimensional flexible scaffold to support, disperse, and structurally support the titanium carbide MXene sheets. While ensuring continuous fiber formation and mechanical flexibility, it achieves a high proportion of titanium carbide MXene loading in the fiber skeleton. It also has high electrochemical energy storage capacity and good flexible stability.

[0018] (3) This invention uses an aqueous dispersion medium and an ethanol coagulation bath, making the solvent system relatively green and environmentally friendly. The preparation process is mild, the process parameters are stable, the spinning continuity is good, and the required equipment is simple and conventional, facilitating continuous preparation and large-scale production. It is suitable for flexible fibrous supercapacitors and related flexible energy storage devices. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the MXene composite fiber electrode with synaptic channels prepared in Example 6 of the present invention. Detailed Implementation

[0020] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0021] Example 1 The present invention relates to a method for preparing MXene composite fiber electrodes with synaptic channels, wherein titanium carbide MXene (Ti3C2T) is used. xMXene powder and oxidized nanocellulose (TOCNF) aqueous dispersion are mixed at a mass ratio of 5:5-9:1. Then, poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) with a total solid content of 8wt%-16wt% is added to form a conductive polymer dispersion. The total solid content is controlled at 2wt%-4wt%. After stirring, the mixture is allowed to stand to remove bubbles, resulting in a composite spinning solution. The composite spinning solution is then injected into anhydrous ethanol or an 80%-90% ethanol aqueous solution coagulation bath through a wet spinning device at a feed rate of 6mL / h-12mL / h. The mixture coagulates to form continuous fibers, which are then dried to obtain MXene-based composite fiber electrodes.

[0022] Specifically, the following steps are included: Step 1: Select titanium carbide MXene powder and oxidized nanocellulose aqueous dispersion with a mass ratio of 5:5-9:1; Step 2: Add titanium carbide MXene powder to deionized water and stir until homogeneous to obtain titanium carbide MXene aqueous dispersion; Step 3: After adding the weighed oxidized nanocellulose aqueous dispersion to the titanium carbide MXene aqueous dispersion and stirring evenly, based on the total solid content of titanium carbide MXene and oxidized nanocellulose, add poly(3,4-ethylenedioxythiophene):polystyrene sulfonate dispersion to form a conductive polymer dispersion. The solid content of the poly(3,4-ethylenedioxythiophene):polystyrene sulfonate dispersion is 8wt%-16wt% of the total solid content of titanium carbide MXene and oxidized nanocellulose; the total solid content of the conductive polymer dispersion is 2wt%-4wt%. Step 4: Stir the conductive polymer dispersion at 800-1500 rpm for 10-24 hours at 20℃-30℃ to obtain the composite spinning solution; the composite spinning solution is an aqueous dispersion system without visible large particle agglomeration, obvious sedimentation or phase separation. Step 5: Let the composite spinning solution stand for 0.5h-2h to achieve defoaming. After defoaming, the composite spinning solution is loaded into an injection device or a continuous wet spinning device and injected into the coagulation bath through an 18G-21G injection needle at a propulsion rate of 6mL / h-12mL / h. The coagulation bath is selected as anhydrous ethanol or an 80%-90% ethanol aqueous solution. Step 6: After the composite spinning solution enters the coagulation bath, solvent exchange and coagulation occur to form continuous composite fibers. Step 7: Take out the solidified continuous composite fiber and dry it by laying it flat or hanging it at 20℃-40℃ for 10min-20min to obtain the MXene-based composite fiber electrode.

[0023] Example 2 Based on Example 1 above, in step 1 of this invention, the oxidized nanocellulose is oxidized nanocellulose with carboxyl groups on its surface; the diameter is 3nm-100nm, the length is 0.5μm-10μm, the aspect ratio is not less than 50, and the carboxyl content is 0.5mmol / g-2.0mmol / g. The solid content of the oxidized nanocellulose aqueous dispersion is 1.0wt%-3.0wt%.

[0024] The solid content in the poly(3,4-ethylenedioxythiophene):polystyrene sulfonate dispersion is 0.8wt%-2.0wt%.

[0025] Example 3 Based on Example 2 above, this embodiment of the present invention uses titanium carbide MXene powder prepared by treating titanium aluminide MAX phase powder with a lithium fluoride / hydrochloric acid etching system. The surface of the titanium carbide MXene contains –O, –OH and / or –F end groups. The preparation process is as follows: Step 1.1: Add lithium fluoride (LiF) to an 8 mol / L-10 mol / L hydrochloric acid (HCl) solution and stir for 5 min-10 min at 35℃-45℃ to obtain the LiF / HCl etching system. Step 1.2: Add titanium aluminum carbide MAX (Ti3AlC2MAX) phase powder to the lithium fluoride / hydrochloric acid etching system and etch by stirring and reacting in a water bath at 35℃-45℃ for 24h-36h. Step 1.3: Centrifuge the etched suspension at a speed of 3000-5000 rpm for 3-10 minutes until the pH of the supernatant is 5-7. Step 1.4: The washed precipitate is redispersed in deionized water, and after vacuum filtration for 5 min-10 min, ultrasonic exfoliation in an ice-water bath for 0.5 h-1.0 h, and freeze drying for 36 h-48 h, titanium carbide MXene powder is obtained.

[0026] The mass ratio of lithium fluoride to titanium aluminide MAX phase powder is 0.5:1-2:1.

[0027] Example 4 Based on Example 3 above, in step 7 of this invention, the continuous composite fiber is dried and then oxidized into a continuous fiber skeleton of nanocellulose, with titanium carbide MXene sheets distributed in the fiber skeleton of oxidized nanocellulose. Poly(3,4-ethylenedioxythiophene): Polystyrene sulfonate is distributed between titanium carbide MXene, at the edge region of titanium carbide MXene, at the interface between titanium carbide MXene and oxidized nanocellulose, or in the multiphase contact region inside the composite fiber.

[0028] Example 5 The MXene composite fiber electrode with synaptic channels of the present invention is prepared by the preparation method of any of the above embodiments; The MXene-based composite fiber electrode has a continuous fibrous structure, with titanium carbide MXene sheets distributed in an overlapping, stacked, and / or networked manner within the composite fiber electrode. Specifically, it is Ti3C2T. x MXene sheets, together with TOCNF and PEDOT:PSS, constitute a ternary composite fiber structure.

[0029] Example 6 Taking the preparation of composite fibers with a PEDOT:PSS addition of 10wt% as an example, the specific fabrication and construction process of the MXene composite fiber electrode with synaptic channels, constructed from MXene sheets, TOCNF, and PEDOT:PSS, is as follows: S1, Ti3C2T x Preparation of MXene powder: LiF was added to a 9 mol / L hydrochloric acid solution and stirred at 40 °C for 10 min to obtain a LiF / HCl etching system. Ti3AlC2MAX phase powder was added to the LiF / HCl etching system, with a mass ratio of LiF to Ti3AlC2MAX phase powder of 1:1. The mixture was stirred and reacted at 40 °C in a water bath for 31 h. The etched suspension was centrifuged at 4000 rpm for 5 min and repeatedly washed with deionized water until the pH of the supernatant was approximately 6.

[0030] The washed precipitate was redispersed in deionized water, and after 8 min of filtration, 1.0 h of ultrasonic exfoliation in an ice-water bath, and 48 h of freeze-drying, Ti3C2T was obtained. x MXene powder.

[0031] S2, Preparation of the composite spinning solution: Select a TOCNF aqueous dispersion with a solid content of 1.5 wt% and a PEDOT:PSS aqueous dispersion with a solid content of 1 wt%. Add Ti3C2T... x MXene powder is dispersed in deionized water and stirred to form Ti3C2T x MXene aqueous dispersion.

[0032] To Ti3C2T x Adding TOCNF aqueous dispersion to MXene aqueous dispersion makes Ti3C2T x MXene and TOCNF were mixed at a mass ratio of 7:3.

[0033] With Ti3C2T xBased on the total solids content of MXene and TOCNF, PEDOT:PSS aqueous dispersion was added to make the PEDOT:PSS solid mass Ti3C2T. x The total solids content of MXene and TOCNF was 10 wt%. The total solids content of the composite spinning solution was controlled at 3 wt%, and the solution was stirred at 1000 rpm for 18 h at 25 °C to obtain the MXene / TOCNF / PEDOT:PSS composite spinning solution.

[0034] S3, Degassing treatment: Let the obtained composite spinning solution stand for 1 hour to degas.

[0035] S4, Wet spinning: The deaerated composite spinning solution is loaded into an injection device and injected into an anhydrous ethanol coagulation bath through a 19G injection needle at a rate of 8 mL / h. After entering the coagulation bath, the composite spinning solution undergoes solvent exchange and coagulation for 20 minutes to form continuous composite fibers.

[0036] S5, Drying treatment: Take out the solidified continuous composite fiber and dry it flat or hanging at 25°C for 15 min to obtain an MXene composite fiber electrode with synaptic channels with a PEDOT:PSS addition of 10wt%.

[0037] The prepared composite fiber electrode, such as Figure 1 As shown, oxidized nanocellulose forms an integral framework, with poly(3,4-ethylenedioxythiophene):polystyrene sulfonate and MXene sheets distributed between the framework, forming a continuous charge transport channel similar to nerve synapse connections, effectively reducing the interfacial contact resistance caused by the insulation of oxidized nanocellulose itself and the discontinuity of multiphase interface contact.

[0038] Example 7 Taking the preparation of composite fibers with a PEDOT:PSS addition of 8wt% as an example, the specific fabrication and construction process of the MXene composite fiber electrode with synaptic channels, constructed from MXene sheets, TOCNF, and PEDOT:PSS, is as follows: S1, Ti3C2T x Preparation of MXene powder: LiF was added to a 10 mol / L hydrochloric acid solution and stirred at 45 °C for 6 min to obtain a LiF / HCl etching system. Ti3AlC2MAX phase powder was added to the LiF / HCl etching system, with a mass ratio of LiF to Ti3AlC2MAX phase powder of 1:1. The mixture was stirred and reacted at 35 °C in a water bath for 36 h. The etched suspension was centrifuged at 4000 rpm for 5 min and repeatedly washed with deionized water until the pH of the supernatant was approximately 5.

[0039] The washed precipitate was redispersed in deionized water, and after 5 min of filtration, 1.0 h of ultrasonic exfoliation in an ice-water bath, and 40 h of freeze-drying, Ti3C2T was obtained. x MXene powder.

[0040] S2, Preparation of the composite spinning solution: Select a TOCNF aqueous dispersion with a solid content of 1 wt% and a PEDOT:PSS aqueous dispersion with a solid content of 0.8 wt%. Add Ti3C2T... x MXene powder is dispersed in deionized water and stirred to form Ti3C2T x MXene aqueous dispersion.

[0041] To Ti3C2T x Adding TOCNF aqueous dispersion to MXene aqueous dispersion makes Ti3C2T x MXene and TOCNF were mixed at a mass ratio of 5:5.

[0042] With Ti3C2T x Based on the total solids content of MXene and TOCNF, PEDOT:PSS aqueous dispersion was added to make the PEDOT:PSS solid mass Ti3C2T. x The total solids content of MXene and TOCNF was 8 wt%. The total solids content of the composite spinning solution was controlled at 2 wt%, and the solution was stirred at 1000 rpm for 18 h at 25 °C to obtain the MXene / TOCNF / PEDOT:PSS composite spinning solution.

[0043] S3, Degassing treatment: Let the obtained composite spinning solution stand for 1 hour to degas.

[0044] S4, Wet spinning: The deaerated composite spinning solution is loaded into an injection device and injected into an anhydrous ethanol coagulation bath at a rate of 6 mL / h through an 18G injection needle. After entering the coagulation bath, the composite spinning solution undergoes solvent exchange and coagulation for 20 minutes to form continuous composite fibers.

[0045] S5, Drying treatment: Take out the solidified continuous composite fiber and dry it flat or hanging at 25°C for 15 min to obtain an MXene composite fiber electrode with synaptic channels with a PEDOT:PSS addition of 8wt%.

[0046] Example 8 Taking the preparation of composite fibers with a PEDOT:PSS addition of 16wt% as an example, the specific fabrication and construction process of the MXene composite fiber electrode with synaptic channels, constructed from MXene sheets, TOCNF, and PEDOT:PSS, is as follows: S1, Ti3C2T xPreparation of MXene powder: LiF was added to an 8 mol / L hydrochloric acid solution and stirred at 45 °C for 6 min to obtain a LiF / HCl etching system. Ti3AlC2MAX phase powder was added to the LiF / HCl etching system, with a mass ratio of LiF to Ti3AlC2MAX phase powder of 1:1. The mixture was stirred and reacted in a 45 °C water bath for 24 h. The etched suspension was centrifuged at 4000 rpm for 5 min and repeatedly washed with deionized water until the pH of the supernatant was approximately 7.

[0047] The washed precipitate was redispersed in deionized water, and after 10 min of filtration, 1 h of ultrasonic exfoliation in an ice-water bath, and 24 h of freeze-drying, Ti3C2T was obtained. x MXene powder.

[0048] S2, Preparation of the composite spinning solution: Select a TOCNF aqueous dispersion with a solid content of 3 wt% and a PEDOT:PSS aqueous dispersion with a solid content of 2 wt%. Add Ti3C2T... x MXene powder is dispersed in deionized water and stirred to form Ti3C2T x MXene aqueous dispersion.

[0049] To Ti3C2T x Adding TOCNF aqueous dispersion to MXene aqueous dispersion makes Ti3C2T x MXene and TOCNF were mixed at a mass ratio of 9:1.

[0050] With Ti3C2T x Based on the total solids content of MXene and TOCNF, PEDOT:PSS aqueous dispersion was added to make the PEDOT:PSS solid mass Ti3C2T. x The total solids content of MXene and TOCNF was 16 wt%. The total solids content of the composite spinning solution was controlled at 4 wt%, and the solution was stirred at 1500 rpm for 24 h at 25 °C to obtain the MXene / TOCNF / PEDOT:PSS composite spinning solution.

[0051] S3, Degassing treatment: Let the obtained composite spinning solution stand for 2 hours to degas.

[0052] S4, Wet spinning: The deaerated composite spinning solution is loaded into an injection device and injected into an anhydrous ethanol coagulation bath at a rate of 12 mL / h through a 21G injection needle. After entering the coagulation bath, the composite spinning solution undergoes solvent exchange and coagulation for 20 minutes to form continuous composite fibers.

[0053] S5, Drying treatment: Take out the solidified continuous composite fiber and dry it flat or hanging at 40℃ for 10 min to obtain an MXene composite fiber electrode with synaptic channels with a PEDOT:PSS addition of 16wt%.

[0054] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0055] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing an MXene composite fiber electrode with synaptic channels, characterized in that, Titanium carbide MXene powder and oxidized nanocellulose aqueous dispersion were mixed at a mass ratio of 5:5-9:

1. Then, poly(3,4-ethylenedioxythiophene):polystyrene sulfonate with a total solid content of 8wt%-16wt% was added to form a conductive polymer dispersion. The total solid content was controlled at 2wt%-4wt%. After stirring, the mixture was allowed to stand to remove bubbles, and a composite spinning solution was obtained. The composite spinning solution was then injected into an anhydrous ethanol or an 80%-90% ethanol aqueous solution coagulation bath through a wet spinning device at a feed rate of 6mL / h-12mL / h. The mixture was coagulated to form continuous fibers, and finally dried to obtain MXene-based composite fiber electrodes.

2. The method for preparing the MXene composite fiber electrode with synaptic channels according to claim 1, characterized in that, Specifically, the following steps are included: Step 1: Select titanium carbide MXene powder and oxidized nanocellulose aqueous dispersion with a mass ratio of 5:5-9:1; Step 2: Add titanium carbide MXene powder to deionized water and stir until homogeneous to obtain titanium carbide MXene aqueous dispersion; Step 3: After adding the weighed oxidized nanocellulose aqueous dispersion to the titanium carbide MXene aqueous dispersion and stirring evenly, based on the total solid content of titanium carbide MXene and oxidized nanocellulose, add poly(3,4-ethylenedioxythiophene):polystyrene sulfonate dispersion to form a conductive polymer dispersion. The solid content of the poly(3,4-ethylenedioxythiophene):polystyrene sulfonate dispersion is 8wt%-16wt% of the total solid content of titanium carbide MXene and oxidized nanocellulose; the total solid content of the conductive polymer dispersion is 2wt%-4wt%. Step 4: Stir the conductive polymer dispersion at 800-1500 rpm for 10-24 hours at 20℃-30℃ to obtain the composite spinning solution; Step 5: Let the composite spinning solution stand for 0.5h-2h to achieve defoaming. After defoaming, the composite spinning solution is loaded into an injection device or a continuous wet spinning device and injected into the coagulation bath through an 18G-21G injection needle at a propulsion rate of 6mL / h-12mL / h. Step 6: After the composite spinning solution enters the coagulation bath, solvent exchange and coagulation occur to form continuous composite fibers. Step 7: Take out the solidified continuous composite fiber and dry it by laying it flat or hanging it at 20℃-40℃ for 10min-20min to obtain the MXene-based composite fiber electrode.

3. The method for preparing the MXene composite fiber electrode with synaptic channels according to claim 2, characterized in that, In step 1, the oxidized nanocellulose is oxidized nanocellulose with carboxyl groups on its surface; the diameter is 3nm-100nm, the length is 0.5μm-10μm, the aspect ratio is not less than 50, and the carboxyl content is 0.5mmol / g-2.0mmol / g. The solid content of the oxidized nanocellulose aqueous dispersion is 1.0wt%-3.0wt%.

4. The method for preparing the MXene composite fiber electrode with synaptic channels according to claim 2, characterized in that, The solid content in the poly(3,4-ethylenedioxythiophene):polystyrene sulfonate dispersion is 0.8wt%-2.0wt%.

5. The method for preparing the MXene composite fiber electrode with synaptic channels according to claim 2, characterized in that, The titanium carbide MXene powder was prepared by treating titanium aluminide MAX phase powder with a lithium fluoride / hydrochloric acid etching system. The preparation process is as follows: Step 1.1: Add lithium fluoride to an 8 mol / L-10 mol / L hydrochloric acid solution and stir at 35℃-45℃ for 5 min-10 min to obtain a lithium fluoride / hydrochloric acid etching system. Step 1.2: Add titanium aluminide MAX phase powder to the lithium fluoride / hydrochloric acid etching system and etch by stirring and reacting in a water bath at 35℃-45℃ for 24h-36h. Step 1.3: Centrifuge the etched suspension at a speed of 3000-5000 rpm for 3-10 minutes until the pH of the supernatant is 5-7. Step 1.4: The washed precipitate is redispersed in deionized water, and after vacuum filtration for 5 min-10 min, ultrasonic exfoliation in an ice-water bath for 0.5 h-1.0 h, and freeze drying for 36 h-48 h, titanium carbide MXene powder is obtained.

6. The method for preparing the MXene composite fiber electrode with synaptic channels according to claim 5, characterized in that, The mass ratio of lithium fluoride to titanium aluminide MAX phase powder is 0.5:1-2:

1.

7. The method for preparing the MXene composite fiber electrode with synaptic channels according to claim 5, characterized in that, The surface of the titanium carbide MXene contains –O, –OH and / or –F end groups.

8. The method for preparing the MXene composite fiber electrode with synaptic channels according to claim 2, characterized in that, The coagulation bath in step 5 is anhydrous ethanol or an aqueous solution of ethanol with a concentration of 80%-90%.

9. The method for preparing the MXene composite fiber electrode with synaptic channels according to claim 2, characterized in that, In step 7, the continuous composite fiber is dried and then oxidized into a continuous fiber skeleton of nanocellulose, with titanium carbide MXene sheets distributed in the fiber skeleton of oxidized nanocellulose. Poly(3,4-ethylenedioxythiophene): Polystyrene sulfonate is distributed between titanium carbide MXene, at the edge region of titanium carbide MXene, at the interface between titanium carbide MXene and oxidized nanocellulose, or in the multiphase contact region inside the composite fiber.

10. An MXene composite fiber electrode with synaptic channels, characterized in that, The MXene-based composite fiber electrode is prepared by any one of the preparation methods described in claims 1-9; The MXene-based composite fiber electrode has a continuous fibrous structure, and the titanium carbide MXene sheets are distributed in an overlapping, stacked and / or networked manner in the composite fiber electrode.

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