Preparation Method and Application of a Composite Material with a Co-Assembled Array Sheath Layer Structure on the Surface of an Aramid Fiber Core Layer

Abstract

The present invention discloses a preparation method and application of a composite material with a co-assembled array sheath layer structure on the surface of an aramid fiber core layer, relating to the technical field of flexible composite materials, and is used to solve the technical problems that the existing fiber-assembled fibrous supercapacitors have low energy density and cannot achieve the balance between mechanical properties and capacitance; the preparation method of the composite material with a co-assembled array sheath layer structure on the surface of an aramid fiber core layer includes: adding aluminum titanium carbide to a lithium fluoride / hydrochloric acid solution, and after stirring and centrifuging, obtaining an MXene solution; adding metallic molybdenum and an ethanol solution to a hydrogen peroxide solution, and performing hydrothermal treatment for 6 to 12 hours to obtain a MoO3 nano-dispersion liquid with oxygen vacancies; obtaining a MoO3 / MXene blend solution; impregnating an aramid nanofiber gel containing magnesium ions into the MoO3 / MXene blend solution, and after drying, obtaining an ANFs@MoO3 / MXene composite material. The present invention is used to provide a preparation method and application of a composite material with a co-assembled array sheath layer structure on the surface of an aramid fiber core layer.

Description

Technical Field

[0001] The present invention relates to the technical field of flexible composite materials, and more specifically, to a preparation method and application of a composite material with an aramid fiber core layer surface co-assembled array sheath layer structure. Background Art

[0002] With the rapid development of human-machine interface (HMI) technology and the Internet of Things (IoT), flexible wearable intelligent devices with multifunctionality and user-friendly features, such as wearable energy storage devices, bioelectronic devices, and stress-strain sensors, are increasingly attracting wide attention. Currently, various materials such as fibers, thin films, and aerogels have been applied to the design of wearable intelligent devices. Among them, multifunctional intelligent fibers exhibit unique importance due to their lightweight, good flexibility, multi-scale design capabilities, and the advantage of integration with large textile systems. Currently, various functional fibers with excellent mechanical and electrochemical properties have been developed, including carbon-based fiber electrodes, pseudocapacitive nanocomposite fibers, and conductive polymer fibers. Using these functional fiber electrodes, corresponding fiber-shaped supercapacitors (FSCs) have been successfully assembled.

[0003] However, the energy density of the fiber-shaped supercapacitors assembled from the above-mentioned fibers is low, and when the above-mentioned fibers meet the mechanical properties (such as high flexibility and strength), their capacitance performance will be affected. That is to say, the balance between mechanical properties and capacitance cannot be achieved. Summary of the Invention

[0004] The purpose of the present invention is to provide a preparation method and application of a composite material with an aramid fiber core layer surface co-assembled array sheath layer structure, which is used to solve the technical problems that the energy density of the fiber-shaped supercapacitors assembled from existing fibers is low and the balance between mechanical properties and capacitance cannot be achieved. In view of this, the present invention is realized through the following solutions.

[0005] In the first aspect, the present invention provides a preparation method of a composite material with an aramid fiber core layer surface co-assembled array sheath layer structure, including:

[0006] Adding aluminum titanium carbide to a lithium fluoride / hydrochloric acid solution, and after stirring and centrifuging, obtaining an MXene solution;

[0007] Adding molybdenum metal and an ethanol solution to a hydrogen peroxide solution, and performing hydrothermal treatment for 6 to 12 hours to obtain a MoO3 nano-dispersion with oxygen vacancies; wherein, the temperature of the hydrothermal treatment is 140 to 180 °C, and the concentration of the ethanol solution is 20 to 50 Vol%;

[0008] Obtaining a MoO3 / MXene blend solution according to the MXene solution and the MoO3 nano-dispersion;

[0009] The aramid nanofiber gel containing magnesium ions was impregnated into the MoO3 / MXene blend solution, and after drying, the ANFs@MoO3 / MXene composite material was obtained.

[0010] Compared with the prior art, the ANFs@MoO3 / MXene composite material prepared by the preparation method of the composite material with an aramid fiber core layer surface co-assembled array sheath layer structure of the present invention has aramid nanofibers (ANFs) as the core layer, and the co-assembled array sheath layer structure is MoO3 / MXene. The co-assembled array sheath layer structure surrounds the aramid nanofibers (ANFs) and is vertically distributed along the central axis of the aramid nanofibers, so that the composite material has a high energy density, as well as excellent mechanical properties and capacitance balance characteristics; specifically, in the present invention, by selecting reasonable reagents or raw materials and controlling the conditions of each step within the above reasonable range, MXene solution was first prepared using aluminum titanium carbide and lithium fluoride / hydrochloric acid solution, and then a MoO3 nano-dispersion with oxygen vacancies was prepared using metallic molybdenum, hydrogen peroxide solution and ethanol solution, and then a MoO3 / MXene blend solution was obtained; further, magnesium ions were introduced into the aramid nanofiber gel in the present invention, and the magnesium ions are uniformly distributed inside and / or on the surface of the aramid nanofiber gel. Through the electrostatic adsorption of the magnesium ions (i.e., positive ions), the MoO3 / MXene blend solution was assembled on the outer surface of the aramid nanofibers (ANFs), and after drying, MoO3 / MXene was vertically distributed along the central axis of the aramid nanofibers (please refer to Figure 1 )), and this special structure of the ANFs@MoO3 / MXene composite material determines that the material has the above excellent properties. Specifically, in the embodiment of the present invention, after the above ANFs@MoO3 / MXene composite material was prepared, its performance was tested. The tensile strength of the ANFs@MoO3 / MXene composite material is 60~100 MPa, the conductivity is 1000~2000 S / cm, and when the current density is 3 mA / cm 3 , its volume specific capacitance is 1300~2700 F / cm 3 , and at a current density of 5 A / g, the charge-discharge cycle is 10,000 times, and the capacitance retention rate is 75~98%. Through the above technical solution of the present invention, the technical problems of the low energy density of the existing fiber-assembled fibrous supercapacitor and the inability to achieve the balance between mechanical properties and capacitance are solved.

[0011] Further, in the preparation method of the composite material with an aramid fiber core layer surface co-assembled array sheath layer structure of the present invention, in the lithium fluoride / hydrochloric acid solution, the concentration of hydrochloric acid is 9~12 mol / L; the volume of hydrochloric acid required for every 4~8 grams of lithium fluoride is 30~120 mL; and / or,

[0012] The mass ratio of the aluminum titanium carbide to the lithium fluoride is 1:(1.6 - 2).

[0013] Furthermore, in the preparation method of the composite material with the co - assembled array sheath layer structure on the surface of the aramid fiber core layer of the present invention, when adding the aluminum titanium carbide into the lithium fluoride / hydrochloric acid solution and obtaining the MXene solution after stirring and centrifuging, it includes:

[0014] Adding the aluminum titanium carbide into the lithium fluoride / hydrochloric acid solution and stirring for 20 - 50 hours at a temperature of 25 - 50°C to obtain a first solution; the stirring rate is 100 - 150 rpm;

[0015] Centrifuging and washing the first solution to neutrality, and then performing ultrasonic treatment for 1 - 2 hours to obtain a second solution; the centrifuging rate is 3000 - 4000 rpm, and the power of the ultrasonic treatment is 100 - 250 W;

[0016] After centrifuging the second solution again, obtaining the supernatant; this supernatant is the MXene solution; wherein, the rate of the second centrifuging is 1000 - 4000 rpm, and the centrifuging time is 0.5 - 2 hours.

[0017] Furthermore, in the preparation method of the composite material with the co - assembled array sheath layer structure on the surface of the aramid fiber core layer of the present invention, during the process of adding molybdenum metal and ethanol solution into the hydrogen peroxide solution, the mass of molybdenum metal required for every 12 - 20 mL of the hydrogen peroxide solution is 0.5 - 2 grams; and / or,

[0018] The volume ratio of the ethanol solution to the hydrogen peroxide solution is 1:(0.5 - 1).

[0019] Furthermore, in the preparation method of the composite material with the co - assembled array sheath layer structure on the surface of the aramid fiber core layer of the present invention, in the MoO3 / MXene blend solution, the volume ratio of the MXene solution to the MoO3 nano - dispersion liquid is 1:(0.05 - 0.15).

[0020] Furthermore, in the preparation method of the composite material with the co - assembled array sheath layer structure on the surface of the aramid fiber core layer of the present invention, during the process of impregnating the aramid nanofiber gel containing magnesium ions into the MoO3 / MXene blend solution, the mass ratio of the aramid nanofiber gel containing magnesium ions to the MoO3 / MXene blend solution is 1:(100 - 150).

[0021] Furthermore, in the preparation method of the composite material with the co - assembled array sheath layer structure on the surface of the aramid fiber core layer of the present invention, the magnesium ion content in the aramid nanofiber gel containing magnesium ions is 5 - 10 wt%;

[0022] and / or,

[0023] Obtaining the aramid nanofiber gel containing magnesium ions includes:

[0024] Dissolving para-aramid fibers to prepare an aramid nanofiber spinning solution with a concentration of 10 - 20 mg / mL;

[0025] Performing spinning treatment on the aramid nanofiber spinning solution, and obtaining an aramid nanofiber gel after solidification; the injection speed of the spinning treatment is 500 - 1000 μL / min, and the coagulation bath is deionized water;

[0026] Immersing the aramid nanofiber gel in a 1 - 10 wt% magnesium chloride hexahydrate solution, mixing evenly to obtain an aramid nanofiber gel containing magnesium ions.

[0027] Furthermore, in the preparation method of the aramid fiber core layer surface co-assembled array sheath layer structure composite material of the present invention, the drying process is carried out in a vacuum environment;

[0028] wherein, the vacuum degree of the vacuum environment is 0.01 - 0.09 MPa, the drying temperature is 35 - 80 °C, and the drying time is 0.5 - 6 hours.

[0029] In a second aspect, the present invention provides an aramid fiber core layer surface co-assembled array sheath layer structure composite material, which is prepared according to the above-mentioned preparation method of the aramid fiber core layer surface co-assembled array sheath layer structure composite material; wherein, the core layer of the aramid fiber core layer surface co-assembled array sheath layer structure composite material is aramid nanofibers, and the co-assembled array sheath layer structure is MoO3 / MXene; the co-assembled array sheath layer structure surrounds the aramid nanofibers and is vertically distributed along the central axis of the aramid nanofibers.

[0030] Compared with the prior art, the beneficial effects of the aramid fiber core layer surface co-assembled array sheath layer structure composite material of the present invention are the same as those of the preparation method of the aramid fiber core layer surface co-assembled array sheath layer structure composite material described in the above technical solution, and will not be elaborated here.

[0031] In a third aspect, the present invention provides an application of the above-mentioned aramid fiber core layer surface co-assembled array sheath layer structure composite material as an electrode. Description of the Drawings

[0032] The drawings described herein are used to provide a further understanding of the present invention, and constitute a part of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0033] Figure 1Partial enlarged schematic diagram of the sheath cross-section structure of the ANFs@MoO3 / MXene composite material prepared in Example 1;

[0034] Figure 2 Schematic diagram of the planar structure of the ANFs@MoO3 / MXene composite material prepared in Example 1;

[0035] Figure 3 Schematic diagram of the cross-section structure of the ANFs@MoO3 / MXene composite material prepared in Example 1;

[0036] Figure 4 XRD pattern of the core layer ANFs of the ANFs@MoO3 / MXene composite material prepared in Example 1;

[0037] Figure 5 XRD pattern of the sheath layer of the ANFs@MoO3 / MXene composite material prepared in Example 1;

[0038] Figure 6 Schematic diagram of the mechanical properties of the ANFs@MoO3 / MXene composite material prepared in the embodiment of the present invention;

[0039] Figure 7 CV schematic diagram of the ANFs@MoO3 / MXene composite material prepared in the embodiment of the present invention as an electrode;

[0040] Figure 8 Schematic diagram of the volume capacity comparison of the ANFs@MoO3 / MXene composite material prepared in the embodiment of the present invention;

[0041] Figure 9 Schematic diagram of the cycle stability of the ANFs@MoO3 / MXene composite material prepared in the embodiment of the present invention when applied as an electrode. Detailed implementation manners

[0042] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0043] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0044] In addition, the terms "first" and "second" are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, "a plurality of" means two or more, unless otherwise specifically defined. "Several" means one or more, unless otherwise specifically defined.

[0045] Currently, various materials such as fibers, films, and aerogels have been applied to the design of wearable smart devices. Among them, multifunctional smart fibers exhibit unique importance due to their lightweight, good flexibility, multi-scale design capabilities, and the advantage of integration with large textile systems. Currently, various functional fibers with excellent mechanical and electrochemical properties have been developed, including carbon-based fiber electrodes, pseudocapacitive nanocomposite fibers, and conductive polymer fibers. Using these functional fiber electrodes, corresponding fibrous supercapacitors (FSCs) have been successfully assembled. However, the fibrous supercapacitors assembled from the above fibers have a low energy density, and when the above fibers meet the mechanical properties (such as high flexibility and strength), their capacitive performance will be affected, that is, the balance between mechanical properties and capacitance cannot be achieved.

[0046] To solve the above technical problems, in a first aspect, the present invention provides a method for preparing a composite material with an array sheath layer structure co-assembled on the surface of an aramid fiber core layer, including:

[0047] Adding aluminum titanium carbide to a lithium fluoride / hydrochloric acid solution, and after stirring and centrifuging, obtaining an MXene solution;

[0048] Adding molybdenum metal and an ethanol solution to a hydrogen peroxide solution, and performing hydrothermal treatment for 6 to 12 hours to obtain a MoO3 nano-dispersion with oxygen vacancies; wherein, the temperature of the hydrothermal treatment is 140 to 180 °C, and the concentration of the ethanol solution is 20 to 50 Vol%;

[0049] Obtaining a MoO3 / MXene blend solution according to the MXene solution and the MoO3 nano-dispersion;

[0050] Impregnating an aramid nanofiber gel containing magnesium ions into the MoO3 / MXene blend solution, and after drying, obtaining an ANFs@MoO3 / MXene composite material.

[0051] Under the above technical solution, the ANFs@MoO3 / MXene composite material prepared by the preparation method of the aramid fiber core layer surface co-assembled array sheath layer structure composite material of the present invention uses aramid nanofibers (ANFs) as the core layer, and the co-assembled array sheath layer structure is MoO3 / MXene. The co-assembled array sheath layer structure surrounds the aramid nanofibers (ANFs) and is vertically distributed along the central axis of the aramid nanofibers, so that the composite material has a high energy density, as well as excellent mechanical properties and capacitance balance characteristics; specifically, the present invention selects reasonable reagents or raw materials and controls the conditions of each step within the above reasonable range. First, a MXene solution is prepared by using aluminum titanium carbide and lithium fluoride / hydrochloric acid solution, and then a MoO3 nano-dispersion with oxygen vacancies is prepared by using molybdenum metal, hydrogen peroxide solution and ethanol solution, and then a MoO3 / MXene blend solution is obtained; further, the present invention introduces magnesium ions into the aramid nanofiber gel, and the magnesium ions are uniformly distributed inside and / or on the surface of the aramid nanofiber gel. Through the adsorption of the magnesium ions (i.e., positive ions), the MoO3 / MXene blend solution is assembled on the outer surface of the aramid nanofibers (ANFs), and after drying, MoO3 / MXene is vertically distributed along the central axis of the aramid nanofibers (please refer to Figure 1 ). This special structure of the ANFs@MoO3 / MXene composite material determines that the material has the above excellent properties. Specifically, in the embodiment of the present invention, after the above ANFs@MoO3 / MXene composite material is prepared, its performance is tested. The tensile strength of the ANFs@MoO3 / MXene composite material is 60~100MPa, the conductivity is 1000~2000S / cm, and at a current density of 3mA / cm 3 , its volume specific capacitance is 1300~2700F / cm 3 , and at a current density of 5A / g, it is charged and discharged 10,000 times, and the capacitance retention rate is 75~98%. Through the above technical solution of the present invention, the technical problems of the low energy density of the existing fiber-assembled fibrous supercapacitor and the inability to achieve the balance between mechanical properties and capacitance are solved; for example, in the above technical solution, the hydrothermal treatment time can be 6 hours, 8 hours, 10 hours or 12 hours, the hydrothermal treatment temperature can be 140°C, 160°C or 180°C, and the concentration of the ethanol solution can be 20Vol%, 35Vol% or 50Vol%.

[0052] It should be understood that in the preparation method of the aramid fiber core layer surface co-assembled array sheath layer structure composite material of the present invention, in order to obtain an array sheath layer structure with excellent performance, that is, in order to obtain excellent performance MXene, the concentration of hydrochloric acid, as well as the dosages of lithium fluoride, hydrochloric acid and aluminum titanium carbide should also be controlled within a reasonable range; by way of example, the concentration of the hydrochloric acid can be 9-12 mol / L, the volume of hydrochloric acid required for every 4-8 grams of lithium fluoride can be 30-120 mL, and the mass ratio of aluminum titanium carbide to lithium fluoride can be 1:(1.6-2); in another example, the concentration of the hydrochloric acid can be 9 mol / L, 11 mol / L or 12 mol / L, the volume of hydrochloric acid required for every 4 grams, 6 grams or 8 grams of lithium fluoride can be 30 mL, 60 mL, 90 mL or 120 mL, and the mass ratio of aluminum titanium carbide to lithium fluoride can be 1:1.6, 1:1.8 or 1:2.

[0053] As a possible implementation manner, in the preparation method of the aramid fiber core layer surface co-assembled array sheath layer structure composite material of the present invention, adding the aluminum titanium carbide into the lithium fluoride / hydrochloric acid solution, and after stirring and centrifuging, obtaining the MXene solution includes:

[0054] Step 1, adding the aluminum titanium carbide into the lithium fluoride / hydrochloric acid solution, and stirring for 20-50 hours at a temperature of 25-50 °C to obtain a first solution; the stirring rate is 100-150 rpm;

[0055] Step 2, centrifuging and washing the first solution until it is neutral, and performing ultrasonic treatment for 1-2 hours to obtain a second solution; the centrifuging rate is 3000-4000 rpm, and the power of the ultrasonic treatment is 100-250 W;

[0056] Step 3, after centrifuging the second solution again, obtaining the supernatant; this supernatant is the MXene solution; wherein, the rate of the second centrifuging is 1000-4000 rpm, and the centrifuging time is 0.5-2 hours.

[0057] Under the above technical solution, in the preparation method of the composite material with an array sheath layer structure co-assembled on the surface of the aramid fiber core layer of the present invention, by controlling the temperature, stirring time, and stirring rate within the above reasonable ranges in step 1, it is beneficial to stably and controllably carry out the reaction of aluminum titanium carbide with lithium fluoride / hydrochloric acid; further, in step 2, by centrifuging and washing until neutral, unreacted aluminum titanium carbide and other impurities can be removed, improving the purity of the MXene solution. Through water bath ultrasonic treatment, the MXene sheets can be further dispersed to prevent their agglomeration, improving the uniformity and stability of the MXene solution; further, in step 3, by centrifuging again, the suspended matter and impurities in the solution can be further removed to obtain a MXene solution with fewer sheets; the MXene solution obtained by this technical solution is black; for example, in the above technical solution, the temperature in step 1 can be 25°C, 35°C, or 50°C, the stirring time can be 20 hours, 35 hours, or 50 hours, and the stirring rate can be 100 rpm, 130 rpm, or 150 rpm; the ultrasonic treatment time in step 2 can be 1 hour, 1.5 hours, or 2 hours, the centrifuging rate can be 3000 rpm, 3500 rpm, or 4000 rpm, and the power of the ultrasonic treatment can be 100 W, 180 W, or 250 W; the centrifuging rate for the second centrifuging in step 3 can be 1000 rpm, 2500 rpm, or 4000 rpm, and the centrifuging time can be 0.5 hour, 1.5 hours, or 2 hours.

[0058] It should be understood that in the preparation method of the composite material with an array sheath layer structure co-assembled on the surface of the aramid fiber core layer of the present invention, in order to obtain an array sheath layer structure with excellent performance, that is, in order to obtain a MoO3 nano-dispersion with excellent performance, the concentration of the hydrogen peroxide solution, and the dosages of the hydrogen peroxide solution, metallic molybdenum, and ethanol solution should also be controlled within reasonable ranges; for example, the concentration of the hydrogen peroxide solution can be 5-15 wt%, the mass of metallic molybdenum required for every 12-20 mL of the hydrogen peroxide solution can be 0.5-2 grams, and the volume ratio of the ethanol solution to the hydrogen peroxide solution can be 1:(0.5-1); in another example, the concentration of the hydrogen peroxide solution can be 5 wt%, 8 wt%, or 15 wt%, the mass of metallic molybdenum required for every 12 mL, 16 mL, or 20 mL of the hydrogen peroxide solution can be 0.5 grams, 1.3 grams, or 2 grams, and the volume ratio of the ethanol solution to the hydrogen peroxide solution can be 1:0.5, 1:0.8, or 1:1.

[0059] As described above, the co-assembled array sheath structure of the ANFs@MoO3 / MXene composite material prepared by the above technical solution of the present invention is MoO3 / MXene. To stably assemble this co-assembled array sheath structure onto the surface of the core layer of aramid nanofibers (ANFs) and make the co-assembled array sheath structure vertically distributed along the central axis of the aramid nanofibers, on the one hand, the present invention introduces magnesium ions into the aramid nanofiber gel. On the other hand, the present invention also needs to control the mixing ratios of the MXene solution, the MoO3 nano-dispersion, and the aramid nanofiber gel containing magnesium ions and the MoO3 / MXene blend solution within a reasonable range. For example, in the MoO3 / MXene blend solution, the volume ratio of the MXene solution to the MoO3 nano-dispersion can be 1:(0.05 - 0.15). During the process of impregnating the aramid nanofiber gel containing magnesium ions into the MoO3 / MXene blend solution, the mass ratio of the aramid nanofiber gel containing magnesium ions to the MoO3 / MXene blend solution can be 1:(100 - 150). As another example, the volume ratio of the MXene solution to the MoO3 nano-dispersion can be 1:0.05, 1:0.1, or 1:0.15, and the mass ratio of the aramid nanofiber gel containing magnesium ions to the MoO3 / MXene blend solution can be 1:100, 1:130, or 1:150.

[0060] As a possible implementation manner, in the preparation method of the composite material with a co-assembled array sheath structure on the surface of the aramid fiber core layer of the present invention, the magnesium ion content in the aramid nanofiber gel containing magnesium ions is 5 - 10 wt%; and / or,

[0061] Obtaining the aramid nanofiber gel containing magnesium ions includes:

[0062] Step 1, dissolving para-aramid fibers to prepare an aramid nanofiber spinning solution with a concentration of 10 - 20 mg / mL;

[0063] Step 2, performing spinning treatment on the aramid nanofiber spinning solution, and obtaining an aramid nanofiber gel after solidification; the injection speed of the spinning treatment is 500 - 1000 μL / min, and the coagulation bath is deionized water;

[0064] Step 3, impregnating the aramid nanofiber gel in a 1 - 10 wt% magnesium chloride hexahydrate solution, mixing evenly, to obtain an aramid nanofiber gel containing magnesium ions.

[0065] In the case of adopting the above technical solution, in the preparation method of the composite material with an aramid fiber core layer surface co-assembled array sheath layer structure of the present invention, by making aramid fibers into an aramid nanofiber spinning solution, and then performing spinning treatment on it, the solidified aramid nanofiber gel is impregnated in a 1-10 wt% magnesium chloride hexahydrate solution, thereby obtaining an aramid nanofiber gel containing magnesium ions; in the above technical solution, for example, the magnesium ion content in the aramid nanofiber gel containing magnesium ions is 5 wt%, 8 wt% or 10 wt%, the concentration of the aramid nanofiber spinning solution can be 10 mg / mL, 15 mg / mL or 20 mg / mL, the injection speed of the spinning treatment can be 500 μL / min, 800 μL / min or 1000 μL / min, and the concentration of the magnesium chloride hexahydrate solution can be 1 wt%, 5 wt% or 10 wt%.

[0066] It should also be understood that in the preparation method of the composite material with an aramid fiber core layer surface co-assembled array sheath layer structure of the present invention, in order to avoid oxidation of the composite material during the drying process and make the prepared composite material have more excellent properties, the present invention controls the above drying process to be carried out in a vacuum environment; for example, the vacuum degree of the vacuum environment can be 0.01-0.09 MPa, the drying temperature can be 35-80 °C, and the drying time can be 0.5-6 hours; in another example, the vacuum degree of the vacuum environment can be 0.01 Mpa, 0.05 Mpa or 0.09 Mpa, the drying temperature can be 35 °C, 55 °C or 80 °C, and the drying time can be 0.5 hours, 3 hours or 6 hours.

[0067] In the second aspect, the present invention provides a composite material with an aramid fiber core layer surface co-assembled array sheath layer structure, which is prepared according to the above preparation method of the composite material with an aramid fiber core layer surface co-assembled array sheath layer structure; wherein, the core layer of the composite material with an aramid fiber core layer surface co-assembled array sheath layer structure is aramid nanofibers, and the co-assembled array sheath layer structure is MoO3 / MXene; the co-assembled array sheath layer structure surrounds the aramid nanofibers and is vertically distributed along the central axis of the aramid nanofibers.

[0068] Under the above technical solutions, the composite material with a co-assembled array sheath structure on the surface of the aramid fiber core layer of the present invention is prepared by using the preparation method of the composite material with a co-assembled array sheath structure on the surface of the aramid fiber core layer. For this ANFs@MoO3 / MXene composite material, aramid nanofibers (ANFs) are used as the core layer, and the co-assembled array sheath structure is MoO3 / MXene. The co-assembled array sheath structure surrounds the aramid nanofibers (ANFs) and is vertically distributed along the central axis of the aramid nanofibers, enabling the composite material to have a high energy density, as well as excellent mechanical properties and capacitance balance characteristics. Specifically, in the present invention, by selecting reasonable reagents or raw materials and controlling the conditions of each step within the above reasonable range, MXene solution is first prepared using aluminum titanium carbide and lithium fluoride / hydrochloric acid solution, and then a MoO3 nano-dispersion with oxygen vacancies is prepared using molybdenum metal and ethanol solution, and further a MoO3 / MXene blend solution is obtained. Further, magnesium ions are introduced into the aramid nanofiber gel in the present invention, and the magnesium ions are uniformly distributed inside and / or on the surface of the aramid nanofiber gel. Through the adsorption of the magnesium ions (i.e., positive ions), the MoO3 / MXene blend solution is assembled on the outer surface of the aramid nanofibers (ANFs), and after drying, MoO3 / MXene is vertically distributed along the central axis of the aramid nanofibers (please refer to Figure 1 ). This special structure of the ANFs@MoO3 / MXene composite material determines that the material has the above excellent properties. Specifically, in the embodiment of the present invention, after the above ANFs@MoO3 / MXene composite material is prepared, its performance is tested. The tensile strength of the ANFs@MoO3 / MXene composite material is 60-100 MPa, the conductivity is 1000-2000 S / cm, and when the current density is 3 mA / cm 3 , its volume specific capacitance is 1300-2700 F / cm 3 , and at a current density of 5 A / g, after 10,000 charge-discharge cycles, the capacitance retention rate is 75-98%.

[0069] In the third aspect, the present invention provides the application of the above composite material with a co-assembled array sheath structure on the surface of the aramid fiber core layer as an electrode.

[0070] To better understand the present invention, the content of the present invention will be further clarified below in conjunction with specific embodiments, but the content of the present invention is not limited to the following embodiments.

[0071] Unless otherwise specified, the raw materials used in the following embodiments are all commercially available raw materials.

[0072] Example 1

[0073] This embodiment provides a method for preparing a composite material with a co-assembled array sheath layer structure on the surface of an aramid fiber core layer, including:

[0074] S100, Add 4.8 g of lithium fluoride (LiF) to 9 mol / L hydrochloric acid and stir mechanically for 10 min. Then slowly add 3 g of titanium aluminum carbide (Ti3AlC2) precursor to the LiF / hydrochloric acid solution, stir and react at 40 °C for 36 h, then perform centrifugation and washing until neutral, and perform ultrasonic treatment (time is 1 h, power is 100 w), and centrifuge again for 1 h to obtain a black supernatant. The black supernatant is a monolayer MXene solution, and the concentration of this MXene solution is 5 mg / mL; the centrifugation rate is 3500 rpm; the amount of hydrochloric acid used is 45 mL;

[0075] S200, Add 0.96 g of molybdenum (Mo) powder to 12.5 mL of hydrogen peroxide (H2O2) solution, and quickly stir in an ice-water bath until the solution turns bright yellow, then add 30 ml of ethanol solution; the volume ratio of ethanol to water in the ethanol solution is 2:1; hydrothermal treatment is carried out at 180 °C for 12 hours to obtain a dispersion of MoO3 nanobelts with oxygen vacancies;

[0076] S300, Add the MoO3 nanobelt dispersion to the MXene solution to obtain a MoO3 / MXene blend solution;

[0077] S400, Use the chemical splitting method to dissolve para-aramid fibers to make a 10 mg / mL aramid nanofiber (ANFs) spinning solution; wherein, the reaction temperature of the chemical splitting method is 25 °C and the reaction time is 7 days;

[0078] S500, Spin the aramid nanofiber (ANFs) spinning solution through a wet spinning process, and obtain an aramid nanofiber gel after solidification; the injection speed is set to 500 μL / min during the spinning process, and the coagulation bath is deionized water;

[0079] S600, Immerse the aramid nanofiber gel in a 1 wt% magnesium chloride hexahydrate solution to obtain an aramid nanofiber gel containing Mg 2+ ; wherein, during the immersion process, the needle gauge is 15G;

[0080] S700, Place the MoO3 / MXene blend solution obtained in step S300 in a petri dish, and then the Mg-containing one in step S600 2+The aramid nanofiber gel was impregnated into the MoO3 / MXene blend solution for 10 minutes to obtain ANFs@MoO3 / MXene hydrogel fibers; the content of the MoO3 nanobelt dispersion in the ANFs@MoO3 / MXene hydrogel fibers was 5 wt%.

[0081] S800, the ANFs@MoO3 / MXene hydrogel fibers from step S700 were dried in a vacuum oven for 1 hour at a drying temperature of 45 °C and a vacuum degree of 0.01 MPa in the vacuum oven, thereby preparing the ANFs@MoO3 / MXene composite material.

[0082] Example 2

[0083] This example provides a method for preparing a composite material with an aramid fiber core layer surface co-assembled array sheath layer structure, including:

[0084] S100, 8 g of lithium fluoride (LiF) was added to 12 mol / L hydrochloric acid and mechanically stirred for 10 minutes, then 5 g of titanium aluminum carbide (Ti3AlC2) precursor was slowly added to the LiF / hydrochloric acid solution, and the mixture was stirred and reacted at 40 °C for 48 hours, followed by centrifugation and washing until neutral, ultrasonic treatment (for 2 hours at a power of 250 W), and centrifugation for 1 hour again to obtain a black supernatant, which was a monolayer MXene solution with a concentration of 20 mg / mL; the centrifugation rate was 3500 rpm; the amount of hydrochloric acid used was 75 mL;

[0085] S200, 1.5 g of molybdenum (Mo) powder was added to 20 mL of hydrogen peroxide (H2O2) solution, and the mixture was rapidly stirred in an ice bath until the solution turned bright yellow, and then 60 ml of ethanol solution was added; the volume ratio of ethanol to water in the ethanol solution was 5:1; hydrothermal treatment was carried out at 180 °C for 12 hours to obtain a MoO3 nanobelt dispersion with oxygen vacancies;

[0086] S300, the MoO3 nanobelt dispersion was added to the MXene solution to obtain a MoO3 / MXene blend solution;

[0087] S400, the para-aramid fiber was dissolved by chemical splitting method to prepare a 20 mg / mL aramid nanofiber (ANFs) spinning solution; wherein, the reaction temperature of the chemical splitting method was 25 °C and the reaction time was 7 days;

[0088] S500, the aramid nanofiber (ANFs) spinning solution was spun by a wet spinning process, and an aramid nanofiber gel was obtained after solidification; the injection speed was set to 1000 μL / min during the spinning process, and the coagulation bath was deionized water;

[0089] S600, impregnate the aramid nanofiber gel in a 1 wt% magnesium chloride hexahydrate solution to obtain an aramid nanofiber gel containing Mg 2+ ; wherein, during the impregnation process, the needle gauge is 15G;

[0090] S700, place the MoO3 / MXene blend solution obtained in step S300 in a petri dish, and then impregnate the aramid nanofiber gel containing Mg 2+ in the MoO3 / MXene blend solution for 40 min to obtain ANFs@MoO3 / MXene hydrogel fibers; the content of the MoO3 nanobelt dispersion in the ANFs@MoO3 / MXene hydrogel fibers is 30 wt%;

[0091] S800, dry the ANFs@MoO3 / MXene hydrogel fibers obtained in step S700 in a vacuum oven for 5 h at a drying temperature of 80 °C and a vacuum degree of 0.09 MPa in the vacuum oven to prepare ANFs@MoO3 / MXene composite materials.

[0092] Example 3

[0093] This example provides a preparation method of a composite material with an aramid fiber core layer surface co-assembled array sheath layer structure, including:

[0094] S100, add 6.4 g of lithium fluoride (LiF) to 10 mol / L hydrochloric acid and mechanically stir for 15 min, then slowly add 4 g of titanium aluminum carbide (Ti3AlC2) precursor to the LiF / hydrochloric acid solution, stir and react at 35 °C for 40 h, then carry out centrifugal washing until neutral, ultrasonic treatment (time is 1.5 h, power is 180 W), and centrifuge again for 1 h to obtain a black supernatant, which is a monolayer MXene solution with a concentration of 15 mg / mL; the centrifugation rate is 3500 rpm; the dosage of hydrochloric acid is 60 mL;

[0095] S200, add 1 g of molybdenum (Mo) powder to 15 mL of hydrogen peroxide (H2O2) solution, and quickly stir in an ice bath until the solution turns bright yellow, then add 40 ml of ethanol solution; the volume ratio of ethanol to water in the ethanol solution is 3:1; hydrothermal treatment is carried out at 180 °C for 12 hours to obtain a MoO3 nanobelt dispersion with oxygen vacancies;

[0096] S300, add the MoO3 nanobelt dispersion to the MXene solution to obtain a MoO3 / MXene blend solution;

[0097] S400, Dissolve para-aramid fiber by chemical splitting method to prepare a 15 mg / mL aramid nanofiber (ANFs) spinning solution; wherein, the reaction temperature of the chemical splitting method is 25 °C and the reaction time is 7 days;

[0098] S500, Spin the aramid nanofiber (ANFs) spinning solution by wet spinning process, and obtain aramid nanofiber gel after solidification; during the spinning process, set the injection speed to 750 μL / min and the coagulation bath to deionized water;

[0099] S600, Immerse the aramid nanofiber gel in a 5 wt% magnesium chloride hexahydrate solution to obtain an aramid nanofiber gel containing Mg 2+ ; wherein, during the immersion process, the needle gauge is 18G;

[0100] S700, Place the MoO3 / MXene blend solution obtained in step S300 in a petri dish, and then immerse the aramid nanofiber gel containing Mg 2+ in the MoO3 / MXene blend solution for 30 min to obtain ANFs@MoO3 / MXene hydrogel fiber; the content of the MoO3 nanobelt dispersion in the ANFs@MoO3 / MXene hydrogel fiber is 20 wt%;

[0101] S800, Dry the ANFs@MoO3 / MXene hydrogel fiber obtained in step S700 in a vacuum oven for 2.5 h at a drying temperature of 60 °C and a vacuum degree of 0.05 MPa in the vacuum oven, thereby preparing the ANFs@MoO3 / MXene composite material.

[0102] Example 4

[0103] This example provides a preparation method of a composite material with a co-assembled array sheath structure on the surface of an aramid fiber core layer, including:

[0104] S100, Add 4.8 g of lithium fluoride (LiF) to 9 mol / L hydrochloric acid and stir mechanically for 15 min, then slowly add 3 g of titanium aluminum carbide (Ti3AlC2) precursor to the LiF / hydrochloric acid solution, stir and react at 40 °C for 48 h, then perform centrifugal washing until neutral, ultrasonic treatment (time is 1 h, power is 100 W), and centrifuge again for 1 h to obtain a black supernatant, and the black supernatant is a single-layer MXene solution with a concentration of 15 mg / mL; the centrifugation rate is 3500 rpm; the dosage of hydrochloric acid is 45 mL;

[0105] S200, Add 0.96 g of molybdenum (Mo) powder into 12.5 mL of hydrogen peroxide (H2O2) solution, and rapidly stir in an ice-water bath until the solution turns bright yellow. Subsequently, add 60 ml of ethanol solution; the volume ratio of ethanol to water in the ethanol solution is 5:1; hydrothermally react at 180 °C for 12 hours to obtain a dispersion of MoO3 nanobelts with oxygen vacancies.

[0106] S300, Add the dispersion of MoO3 nanobelts into the MXene solution to obtain a MoO3 / MXene blend solution.

[0107] S400, Dissolve para-aramid fibers by chemical splitting method to prepare an aramid nanofiber (ANFs) spinning solution with a concentration of 15 mg / mL; wherein, the reaction temperature of the chemical splitting method is 25 °C and the reaction time is 7 days.

[0108] S500, Spin the aramid nanofiber (ANFs) spinning solution through a wet spinning process, and obtain an aramid nanofiber gel after solidification; the injection speed is set to 750 μL / min during the spinning process, and the coagulation bath is deionized water.

[0109] S600, Immerse the aramid nanofiber gel in a 6 wt% magnesium chloride hexahydrate solution to obtain an aramid nanofiber gel containing Mg 2+ ; wherein, during the immersion process, the needle gauge is 18G.

[0110] S700, Place the MoO3 / MXene blend solution obtained in step S300 in a petri dish, and then immerse the aramid nanofiber gel containing Mg 2+ in the MoO3 / MXene blend solution for 20 min to obtain ANFs@MoO3 / MXene hydrogel fibers; the content of the MoO3 nanobelt dispersion in the ANFs@MoO3 / MXene hydrogel fibers is 15 wt%.

[0111] S800, Dry the ANFs@MoO3 / MXene hydrogel fibers obtained in step S700 in a vacuum oven for 5 h at a drying temperature of 60 °C and a vacuum degree of 0.01 MPa in the vacuum oven, thereby preparing the ANFs@MoO3 / MXene composite material.

[0112] Example 5

[0113] This example provides a method for preparing a composite material with a co-assembled array sheath structure on the surface of an aramid fiber core layer, including:

[0114] S100, Add 4.8 g of lithium fluoride (LiF) to 9 mol / L hydrochloric acid and stir mechanically for 15 min. Then slowly add 3 g of titanium aluminum carbide (Ti3AlC2) precursor to the LiF / hydrochloric acid solution, stir and react at 40 °C for 48 h, then perform centrifugal washing until neutral, followed by ultrasonic treatment (for 1 h at a power of 100 W), and centrifuge again for 1 h to obtain a black supernatant. The black supernatant is a monolayer MXene solution with a concentration of 15 mg / mL; the centrifugation rate is 3500 rpm; the amount of hydrochloric acid used is 45 mL;

[0115] S200, Add 0.96 g of molybdenum (Mo) powder to 12.5 mL of hydrogen peroxide (H2O2) solution, and stir rapidly in an ice-water bath until the solution turns bright yellow. Subsequently, add 60 ml of ethanol solution; the volume ratio of ethanol to water in the ethanol solution is 5:1; hydrothermally react at 180 °C for 12 hours to obtain a dispersion of molybdenum trioxide (MoO3) nanoribbons with oxygen vacancies;

[0116] S300, Add the dispersion of MoO3 nanoribbons to the MXene solution to obtain a MoO3 / MXene blend solution;

[0117] S400, Use the chemical splitting method to dissolve para-aramid fibers to prepare an aramid nanofiber (ANFs) spinning solution with a concentration of 15 mg / mL; among them, the reaction temperature of the chemical splitting method is 25 °C and the reaction time is 7 days;

[0118] S500, Spin the aramid nanofiber (ANFs) spinning solution through a wet spinning process, and obtain an aramid nanofiber gel after solidification; the injection speed is set at 750 μL / min during the spinning process, and the coagulation bath is deionized water;

[0119] S600, Immerse the aramid nanofiber gel in a 6 wt% magnesium chloride hexahydrate solution to obtain an aramid nanofiber gel containing Mg 2+ ; among them, during the immersion process, the needle gauge is 18G;

[0120] S700, Place the MoO3 / MXene blend solution obtained in step S300 in a petri dish, and then immerse the aramid nanofiber gel containing Mg 2+ from step S600 into the MoO3 / MXene blend solution for 20 min to obtain ANFs@MoO3 / MXene hydrogel fibers; the content of the MoO3 nanoribbon dispersion in the ANFs@MoO3 / MXene hydrogel fibers is 5 wt%;

[0121] S800, dry the ANFs@MoO3 / MXene hydrogel fibers from step S700 in a vacuum oven for 5 h at a drying temperature of 60 °C and a vacuum degree of 0.01 MPa in the vacuum oven, thereby preparing the ANFs@MoO3 / MXene composite material.

[0122] In the above embodiments, the concentration of the hydrogen peroxide (H2O2) solution is 8 wt%; the ANFs@MoO3 / MXene composite material prepared in the above embodiments of the present invention can be used as an electrode, and the composite material was characterized and its performance was tested. Please refer to Figures 1 to 3 , Figure 1 FIG. is a partially enlarged schematic view of the sheath cross-sectional structure of the ANFs@MoO3 / MXene composite material prepared in Example 1 of the present invention. Figure 2 FIG. is a schematic plan view of the ANFs@MoO3 / MXene composite material prepared in Example 1. Figure 3 FIG. is a schematic cross-sectional view of the ANFs@MoO3 / MXene composite material prepared in Example 1; specifically, from Figure 1 it can be seen that the sheath is an array structure arranged vertically along the core layer, and this special structure setting can improve the electrochemical activity and electron / ion transport efficiency of the composite material; from Figure 2 it can be seen that the surface of the composite material also shows an array distribution in the horizontal direction, and the molybdenum trioxide (MoO3) nanowires are uniformly distributed in MXene; from Figure 3 it can be seen that the core layer of the composite material is aramid nanofibers (ANFs), and the aramid nanofibers provide excellent mechanical strength, flexibility and stability for the composite material. The sheath layer is a composite layer of MoO3 and MXene. Among them, MoO3 improves the energy storage performance of the composite material, and MXene provides high conductivity and excellent surface functional characteristics for the composite material, further enhancing the electrode performance. From Figure 4 it can be seen that in the ANFs@MoO3 / MXene composite material of Example 1, obvious peaks appeared in the XRD diffraction pattern of the core layer aramid nanofibers (ANFs) at 20.5°, 22.9° and 28.6°, corresponding to the characteristic diffraction peaks of its (110), (200) and (004) planes respectively; from Figure 5 it can be seen that in the ANFs@MoO3 / MXene composite material of Example 1, there is an obvious diffraction peak at 7.5° in the XRD spectrum of the sheath layer MoO3 / MXene, which is the characteristic diffraction peak of the (002) plane of MXene; and the positions at 25.3° and 38.7° are the characteristic diffraction peaks of the (040) and (060) planes of MoO3 respectively; through Figure 4 and Figure 5It can be seen that the ANFs@MoO3 / MXene composite material with a core layer and a sheath layer was successfully prepared in the above Example 1.

[0123] Furthermore, please refer to Figure 6 , it can be seen from Figure 6 that in the ANFs@MoO3 / MXene composite material prepared by the present invention, as the content of MoO3 increases, its tensile strength has been decreasing, but its elongation at break has always remained above 10%, indicating that the composite material has good flexibility and can meet wide applications in actual use; it can be seen from Figure 7 that the present invention uses a three-electrode system to test the electrochemical performance of the ANFs@MoO3 / MXene composite material. It can be seen from Figure 7 that several pairs of asymmetric redox peaks appear when the voltage sweep rate is 1 mV / s (2500 F cm -3 ), proving that the composite material has a pseudocapacitance contribution. At a high voltage sweep rate of 20 mV / s (1450 F cm -3 ), there are still obvious redox peaks of MoO3, indicating that the introduction of oxygen vacancies greatly improves the capacity of the fiber electrode and the characteristics of rapid ion transport in the Faraday reaction. It can be seen from Figure 8 that in the ANFs@MoO3 / MXene composite material prepared by the present invention, with the addition of MoO 3 , it can be seen that the specific capacitance of the composite material is higher than that of the MXene electrode, reflecting the capacity contribution of MoO3 as an electrochemically active material to the composite material. As the content of MoO3 in the composite material gradually increases, the volume specific capacitance of the composite material first increases and then decreases. The main reason is that the increase in the content of MoO3 will inevitably lead to an increase in the electrode radius, thereby affecting its volume and reducing the volume specific capacitance. It can be seen from Figure 9 that when the ANFs@MoO3 / MXene composite material prepared by the present invention is used as an electrode, after 1000 charge-discharge cycles, the capacitance retention rate is 98%, indicating its good cycle stability performance. Furthermore, in combination with Figures 6 to 9 , in the above embodiments of the present invention, the ANFs@MoO3 / MXene composite material prepared in Example 1 has high mechanical properties and good electrochemical properties. Its tensile strength is 60 MPa, the conductivity is 1000 S / cm, and when the current density is 3 mA / cm 3 , its volume specific capacitance is 1400 F / cm 3, at a current density of 5 A / g, after 10,000 charge-discharge cycles, the capacitance retention rate is 85%; the tensile strength of the ANFs@MoO3 / MXene composite material prepared in Example 2 is 80 MPa, the conductivity is 1450 S / cm, and at a current density of 3 mA / cm 3 , its volume specific capacitance is 2200 F / cm 3 , at a current density of 5 A / g, after 10,000 charge-discharge cycles, the capacitance retention rate is 88%; the tensile strength of the ANFs@MoO3 / MXene composite material prepared in Example 3 is 85 MPa, the conductivity is 1500 S / cm, and at a current density of 3 mA / cm 3 , its volume specific capacitance is 2400 F / cm 3 , at a current density of 5 A / g, after 10,000 charge-discharge cycles, the capacitance retention rate is 90%; the tensile strength of the ANFs@MoO3 / MXene composite material prepared in Example 4 is 85 MPa, the conductivity is 1700 S / cm, and at a current density of 3 mA / cm 3 , its volume specific capacitance is 2700 F / cm 3 , at a current density of 5 A / g, after 10,000 charge-discharge cycles, the capacitance retention rate is 98%; the tensile strength of the ANFs@MoO3 / MXene composite material prepared in Example 5 is 85 MPa, the conductivity is 1900 S / cm, and at a current density of 3 mA / cm 3 , its volume specific capacitance is 2400 F / cm 3 , at a current density of 5 A / g, after 10,000 charge-discharge cycles, the capacitance retention rate is 95%. Through the above technical solutions of the present invention, the technical problems of the existing fiber-assembled fibrous supercapacitor with low energy density and the inability to achieve a balance between mechanical properties and capacitance are solved.

[0124] In the description of the above embodiments, specific features, structures, materials or characteristics may be combined in a suitable manner in any one or more embodiments or examples.

[0125] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, and all of them should be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A preparation method of a composite material with a co-assembled array sheath layer structure on the surface of an aramid fiber core layer, characterized in that, Comprising: Adding aluminum titanium carbide into a lithium fluoride / hydrochloric acid solution and stirring for 20 - 50 hours at a temperature of 25 - 50 °C to obtain a first solution; The stirring rate is 100 - 150 rpm; Centrifuging and washing the first solution to neutrality, and performing ultrasonic treatment for 1 - 2 hours to obtain a second solution; the centrifuging rate is 3000 - 4000 rpm, and the power of the ultrasonic treatment is 100 - 250 W; After centrifuging the second solution again, obtaining the supernatant; this supernatant is the MXene solution; wherein, the rate of the second centrifuging is 1000 - 4000 rpm, and the centrifuging time is 0.5 - 2 hours; Adding metallic molybdenum and an ethanol solution into a hydrogen peroxide solution and performing hydrothermal treatment for 6 - 12 hours to obtain a MoO₃ nano-dispersion with oxygen vacancies; wherein, the temperature of the hydrothermal treatment is 140 - 180 °C, the concentration of the ethanol solution is 20 - 50 Vol%, the mass of metallic molybdenum required for every 12 - 20 mL of the hydrogen peroxide solution is 0.5 - 2 grams, and the volume ratio of the ethanol solution to the hydrogen peroxide solution is 1:(0.5 - 1); Obtaining a MoO₃ / MXene blend solution according to the MXene solution and the MoO₃ nano-dispersion; Impregnating an aramid nanofiber gel containing magnesium ions into the MoO₃ / MXene blend solution, and after drying, obtaining an ANFs@MoO₃ / MXene composite material; wherein, the mass ratio of the aramid nanofiber gel containing magnesium ions to the MoO₃ / MXene blend solution is 1:(100 - 150); Among them, obtaining the aramid nanofiber gel containing magnesium ions includes: Dissolving para-aramid fibers to make an aramid nanofiber spinning solution with a concentration of 10 - 20 mg / mL; Performing spinning treatment on the aramid nanofiber spinning solution, and after solidification, obtaining an aramid nanofiber gel; the injection speed of the spinning treatment is 500 - 1000 μL / min, and the coagulation bath is deionized water; Impregnating the aramid nanofiber gel into a 1 - 10 wt% magnesium chloride hexahydrate solution, and mixing evenly to obtain an aramid nanofiber gel containing magnesium ions.

2. The preparation method of the composite material with an aramid fiber core layer surface co-assembled array sheath layer structure according to claim 1, characterized in that In the lithium fluoride / hydrochloric acid solution, the concentration of hydrochloric acid is 9 - 12 mol / L; the volume of hydrochloric acid required for every 4 - 8 grams of lithium fluoride is 30 - 120 mL; The mass ratio of the aluminum titanium carbide to the lithium fluoride is 1:(1.6 - 2).

3. The preparation method of the composite material with an aramid fiber core layer surface co-assembled array sheath layer structure according to claim 2, wherein, In the MoO₃ / MXene blend solution, the volume ratio of the MXene solution to the MoO₃ nano-dispersion is 1:(0.05 - 0.15).

4. The preparation method of the composite material with an aramid fiber core layer surface co-assembled array sheath layer structure according to claim 3, characterized in that The magnesium ion content in the aramid nanofiber gel containing magnesium ions is 5 - 10 wt%.

5. The preparation method of the aramid fiber core layer surface co-assembled array sheath layer structure composite material according to claim 4, characterized in that, The drying process is carried out in a vacuum environment; Among them, the vacuum degree of the vacuum environment is 0.01 - 0.09 MPa, the drying temperature is 35 - 80 °C, and the drying time is 0.5 - 6 hours.

6. A composite material with a co-assembled array sheath layer structure on the surface of an aramid fiber core layer, characterized in that, Prepared according to the preparation method of the aramid fiber core layer surface co-assembled array sheath layer structure composite material described in any one of claims 1 - 5; Among them, the core layer of the composite material with a co-assembled array sheath layer structure on the surface of the aramid fiber core layer is aramid nanofibers, and the co-assembled array sheath layer structure is MoO3 / MXene; the co-assembled array sheath layer structure surrounds the aramid nanofibers and is vertically distributed along the central axis of the aramid nanofibers.

7. Application of the composite material with a co-assembled array sheath layer structure on the surface of the aramid fiber core layer as claimed in claim 6 as an electrode.

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