A carbon fiber fabric-based flexible electrode and its preparation method

Abstract

The invention belongs to the technical field of flexible electrode materials and discloses a carbon fiber fabric-based flexible electrode and a preparation method thereof. The method comprises the following steps: performing an oxidation treatment on a carbon fiber fabric, placing the pre-oxidized carbon fiber fabric in a Co(NO3)2·6H2O solution and performing vacuum impregnation; adding the vacuum-impregnated fabric to a 2-methylimidazole solution, performing an in-situ growth of AIF-L reaction, and obtaining a ZIF-L-modified carbon fiber fabric after washing and drying; placing the ZIF-L-modified carbon fiber fabric in an APS solution and performing impregnation to obtain an impregnated fabric; adding the impregnated fabric to an aniline acid solution and performing an in-situ redox reaction to obtain a PANI@ZIF-L modified carbon fiber fabric; and performing vacuum drying to obtain a carbon fiber fabric-based flexible electrode. The method realizes the preparation of a supercapacitor flexible electrode having good mechanical properties, high electrochemical properties, and high cycle stability.

Description

Technical Field

[0001] The present invention belongs to the technical field of flexible electrode materials, and in particular relates to a carbon fiber fabric-based flexible electrode and a preparation method thereof. Background Art

[0002] To meet the needs of wearable portable devices, energy storage devices have been developing in the direction of safety, lightweight and flexibility, further stimulating the growing demand for flexible energy storage devices. Flexible supercapacitors stand out among many energy storage devices because they have comparable power density and long cycle life to traditional capacitors, and are safe, fast charging and discharging, superior flexibility and low environmental pollution. They are perfectly compatible with the development needs of wearable smart devices.

[0003] In the field of high-performance flexible supercapacitors, textile materials are ideal flexible substrates and promising functional components. Compared with other flexible substrates, the most obvious feature of textile materials is hierarchical structural fibers containing multi-scale geometric structures. Moreover, due to their high conductivity, good flexibility and mechanical properties, textile materials are ideal flexible substrates for carrying active materials.

[0004] At present, flexible electrodes are constructed by growing pseudocapacitive materials on the surface of fabrics, but their low conductivity greatly hinders their capacitance performance. Although conductive polymer electrode materials have the advantages of large theoretical specific capacitance, good conductivity, low cost, and easy preparation, they have been widely used in supercapacitors. However, the conductive polymer materials themselves are too rigid and difficult to load on the surface of carbon fiber fabrics. After severe mechanical deformation, they are easily detached from the support, resulting in low cycle stability and specific capacity of the electrode materials. Summary of the Invention

[0005] In response to the technical problems existing in the prior art, the present invention provides a carbon fiber fabric-based flexible electrode and a preparation method thereof to solve the technical problems of low conductivity, stability and specific capacity of the existing flexible electrodes.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] The present invention provides a method for preparing a carbon fiber fabric-based flexible electrode, comprising:

[0008] performing oxidation treatment on the carbon fiber fabric to obtain pre-oxidized carbon fiber fabric;

[0009] The pre-oxidized carbon fiber fabric is placed in a Co(NO3)2·6H2O solution for vacuum impregnation to obtain a vacuum-impregnated fabric; the vacuum-impregnated fabric is added to a 2-methylimidazole solution for in-situ growth of AIF-L, and after washing and drying, a ZIF-L modified carbon fiber fabric is obtained;

[0010] The ZIF-L modified carbon fiber fabric is placed in an APS solution for impregnation to obtain an impregnated fabric; the impregnated fabric is added to an aniline solution for in-situ redox reaction to obtain a PANI@ZIF-L modified carbon fiber fabric;

[0011] The PANI@ZIF-L modified carbon fiber fabric is vacuum dried to obtain the carbon fiber fabric-based flexible electrode.

[0012] Furthermore, the carbon fiber fabric is subjected to oxidation treatment to obtain a pre-oxidized carbon fiber fabric, as follows:

[0013] The carbon fiber fabric is immersed in a mixed acid solution, stirred in a water bath and then washed to obtain a pre-oxidized carbon fiber fabric; wherein the mixed acid solution is a mixture of concentrated nitric acid and concentrated sulfuric acid.

[0014] Furthermore, the carbon fiber fabric is immersed in the mixed acid solution, stirred in a water bath and then washed to obtain the pre-oxidized carbon fiber fabric. The water bath stirring temperature is 35-50° C. and the stirring time is 1-4 hours.

[0015] Furthermore, the pre-oxidized carbon fiber fabric is placed in a Co(NO3)2·6H2O solution for vacuum impregnation. In the process of obtaining the vacuum-impregnated fabric, the vacuum degree of the vacuum impregnation is 0.01-0.1 MPa and the temperature is 60-100°C; wherein the concentration of the Co(NO3)2·6H2O solution is 0.1-0.5 mmol / mL.

[0016] Furthermore, the vacuum-impregnated fabric is added to a 2-methylimidazole solution to perform an in-situ AIF-L growth reaction. After washing and drying, the ZIF-L modified carbon fiber fabric is obtained. The in-situ AIF-L growth reaction time is 2-4 hours and the drying temperature is 60-80°C; wherein the concentration of the 2-methylimidazole solution is 8-10 mmol / mL.

[0017] Furthermore, the ZIF-L modified carbon fiber fabric is placed in an APS solution for impregnation. In the process of obtaining the impregnated fabric, the impregnation time is 1-3 hours and the temperature is 4-10°C.

[0018] Furthermore, the impregnated fabric is added to an aniline acid solution to perform an in-situ redox reaction to obtain a PANI@ZIF-L modified carbon fiber fabric. The in-situ redox reaction lasts for 2-4 hours and the temperature is 4-10°C.

[0019] Furthermore, during the vacuum drying process of the PANI@ZIF-L modified carbon fiber fabric, the drying temperature is 60-100° C., the drying time is 1-10 h, and the vacuum degree is 0.01-0.09 MPa.

[0020] The present invention also provides a carbon fiber fabric-based flexible electrode, which is prepared using the method for preparing a carbon fiber fabric-based flexible electrode.

[0021] Furthermore, the conductivity of the carbon fiber fabric-based flexible electrode is 500-2400 S / cm; at a current density of 1 mA / cm 2 When the area specific capacitance is 800-2000mF / cm -2 ; at 20mA / cm 2 At a current density of 10,000, the charge and discharge cycles are repeated 10,000 times, and the capacitance retention rate is 60-90%.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The present invention provides a carbon fiber fabric-based flexible electrode and a preparation method thereof, wherein ZIF-L modified carbon fiber fabric is obtained by in-situ growth of ZIF-L on pre-oxidized carbon fiber fabric, and PANI@ZIF-L modified carbon fiber fabric is obtained by in-situ redox reaction with aniline solution, and then dried to obtain a carbon fiber fabric-based flexible electrode; wherein the carbon fiber fabric is selected as the supporting structure of the flexible electrode to improve the flexibility of the electrode; the metal organic framework ZIF-L is used as the active material to provide capacity, and a load platform with high specific surface area and porosity is provided to ensure that ions are charged and discharged. Rapid transfer and diffusion during the process; PANI is used as a conductive layer and an active layer to improve the conductivity and electrochemical performance of the electrode; by regulating the content of ZIF-L and PANI in the carbon fiber fabric, a flexible electrode for supercapacitors with good mechanical properties, high electrochemical properties, and high cycle stability can be prepared; in the present invention, the flexible electrode prepared by using carbon fiber fabric, ZIF-L and PANI has high conductivity, good electrochemical properties and high stability, and the conductivity of the carbon fiber-based flexible electrode is 500-2400S / cm; at a current density of 1mA / cm 2 When the area specific capacitance is 800-2000mF / cm -2 ; at 20mA / cm 2 At a current density of 10,000, the charge and discharge cycles are repeated 10,000 times, and the capacitance retention rate is 60-90%. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0025] Figure 1 is the SEM image of the carbon fiber fabric in Example 4;

[0026] Figure 2 This is the SEM image of the ZIF-L modified carbon fiber fabric in Example 4. DETAILED DESCRIPTION

[0027] In order to make the technical problems, technical solutions, and beneficial effects solved by this application more clearly understood, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of this application; it is obvious that the described embodiments are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of this application.

[0028] The present invention provides a method for preparing a carbon fiber fabric-based flexible electrode, comprising the following steps:

[0029] Step 1: impregnating the carbon fiber fabric with a mixed acid solution, stirring the mixture in a water bath at 35-50° C. for 1-4 hours, and washing the mixture with a large amount of deionized water multiple times to obtain a pre-oxidized carbon fiber fabric; wherein the mixed acid solution is obtained by mixing concentrated nitric acid and concentrated sulfuric acid in a volume ratio of 1:1-4, the mass fraction of the concentrated nitric acid is 65.0%-68.0%, and the mass fraction of the concentrated sulfuric acid is 95.0%-98.0%.

[0030] Step 2: Add 2-10 mmol of Co(NO3)2·6H2O to deionized water and ultrasonically disperse for 5-15 minutes to obtain a Co(NO3)2·6H2O solution with a concentration of 0.1-0.5 mmol / mL; add 16-20 mmol of 2-methylimidazole to deionized water and ultrasonically disperse for 5-15 minutes to obtain a 2-methylimidazole solution with a concentration of 8-10 mmol / mL.

[0031] Step 3: Place 7.5-10 mmol of ammonium persulfate (APS) in an ice-water bath at 0-5°C and mechanically stir for 0.5-2 hours to obtain an APS solution; place 3-8 mmol of aniline monomer in an ice-water bath at 0-5°C and mechanically stir for 0.5-1.5 hours, and then disperse in a hydrochloric acid solution with a concentration of 1-5 mol / L to obtain an aniline acid solution with a concentration of 0.15-0.4 mmol / mL.

[0032] Step 4: placing the pre-oxidized carbon fiber fabric in the Co(NO3)2·6H2O solution prepared in step 2, and performing vacuum impregnation for 1-4 hours at a vacuum degree of 0.01-0.1 MPa and a temperature of 60-100°C to obtain a vacuum-impregnated fabric; transferring the vacuum-impregnated fabric to the 2-methylimidazole solution prepared in step 2, and performing an in-situ growth ZIF-L reaction for 2-4 hours. After the reaction is completed, the fabric is washed with deionized water and anhydrous ethanol several times, and dried in a blast drying oven at 60-80°C to obtain a ZIF-L modified carbon fiber fabric.

[0033] Step 5. Place the ZIF-L modified carbon fiber fabric in step 4 in the APS solution prepared in step 3, and immerse it at a temperature of 4-10°C for 1-3 hours to obtain an impregnated fabric; transfer the impregnated fabric to the aniline acid solution prepared in step 3, and perform an in situ redox reaction at 4-10°C for 2-4 hours to grow a conductive polymer polyaniline (PANI) on the surface of the ZIF-L modified carbon fiber fabric to obtain PANI@ZIF-L modified carbon fiber fabric.

[0034] Step 6: Place the PANI@ZIF-L modified carbon fiber fabric in step 5 in a vacuum drying oven and perform vacuum drying treatment at a vacuum degree of 0.01-0.09 MPa and a drying temperature of 60-100° C. to obtain the carbon fiber fabric-based flexible electrode.

[0035] In the present invention, the carbon fiber fabric-based flexible electrode prepared by using carbon fiber fabric, ZIF-L and PANI has high electrical conductivity and good electrochemical performance; specifically, the conductivity of the carbon fiber fabric-based flexible electrode is 500-2400S / cm; at a current density of 1mA / cm 2 When the area specific capacitance is 800-2000mF / cm -2 ; at 20mA / cm 2 At a current density of 10,000, the charge and discharge cycles are repeated 10,000 times, and the capacitance retention rate is 60-90%.

[0036] Preparation principle:

[0037] The preparation method of the carbon fiber fabric-based flexible electrode described in the present invention adopts carbon fiber fabric as the support structure of the flexible electrode and uses carbon fiber fabric as the substrate, which effectively improves the flexibility of the electrode; the carbon fiber fabric is pre-oxidized by using a mixed acid solution of concentrated nitric acid and concentrated sulfuric acid, and the surface of the oxidized carbon fiber fabric becomes rough, thereby improving the surface activity of the carbon fiber fabric, so that some functional groups are oxidized and can react with external compounds; the pre-oxidized carbon fiber fabric is placed in a Co(NO3)2·6H2O solution for vacuum impregnation, and then transferred to a 2-methylimidazole solution for in-situ growth of ZIF-L reaction, using the metal organic framework ZIF-L as the active The ZIF-L modified carbon fiber fabric is immersed in an APS solution and then transferred to an aniline acid solution for in situ redox reaction to grow a conductive polymer polyaniline on the surface of the ZIF-L modified carbon fiber fabric, thereby realizing the use of PANI as a conductive layer and an active layer to improve the conductivity and electrochemical properties of the electrode. It should be noted that by regulating the content of ZIF-L and PANI in the carbon fiber fabric, an electrode for a supercapacitor with good mechanical properties, high electrochemical properties and high cycle stability is prepared.

[0038] Example 1

[0039] This embodiment 1 provides a method for preparing a carbon fiber fabric-based flexible electrode, comprising the following steps:

[0040] Step 1: impregnate the carbon fiber fabric with a mixed acid solution, stir it in a water bath at 35°C for 1 hour, and wash it with a large amount of deionized water several times to obtain a pre-oxidized carbon fiber fabric; wherein the mixed acid solution is obtained by mixing concentrated nitric acid and concentrated sulfuric acid in a volume ratio of 1:1, the mass fraction of the concentrated nitric acid is 65%, and the mass fraction of the concentrated sulfuric acid is 95%.

[0041] Step 2: Add 2 mmol of Co(NO3)2·6H2O to deionized water and ultrasonically disperse for 5 minutes to obtain a Co(NO3)2·6H2O solution with a concentration of 0.1 mmol / mL; add 16 mmol of 2-methylimidazole to deionized water and ultrasonically disperse for 5 minutes to obtain a 2-methylimidazole solution with a concentration of 8 mmol / mL.

[0042] Step 3: Place 7.5 mmol of ammonium persulfate (APS) in an ice-water bath at 0°C and mechanically stir for 0.5 h to obtain an APS solution; place 3 mmol of aniline monomer in an ice-water bath at 0°C and mechanically stir for 0.5 h, then disperse in a hydrochloric acid solution with a concentration of 1 mol / L to obtain an aniline acid solution with a concentration of 0.15 mmol / mL.

[0043] Step 4: placing the pre-oxidized carbon fiber fabric in the Co(NO3)2·6H2O solution prepared in step 2, and performing vacuum impregnation at a vacuum degree of 0.01 MPa and a temperature of 60°C for 1 hour to obtain a vacuum-impregnated fabric; transferring the vacuum-impregnated fabric to the 2-methylimidazole solution prepared in step 2, and performing an in situ growth ZIF-L reaction for 2 hours. After the reaction is completed, the fabric is washed with deionized water and anhydrous ethanol several times, and dried in a blast drying oven at 60°C to obtain a ZIF-L modified carbon fiber fabric.

[0044] Step 5. Place the ZIF-L modified carbon fiber fabric in step 4 in the APS solution prepared in step 3, and immerse it at a temperature of 4°C for 1 hour to obtain an impregnated fabric; transfer the impregnated fabric to the aniline acid solution prepared in step 3, and perform an in situ redox reaction at 4°C for 2 hours to grow a conductive polymer polyaniline (PANI) on the surface of the ZIF-L modified carbon fiber fabric to obtain PANI@ZIF-L modified carbon fiber fabric.

[0045] Step 6: Place the PANI@ZIF-L modified carbon fiber fabric in step 5 in a vacuum drying oven and perform vacuum drying treatment at a vacuum degree of 0.01 MPa and a drying temperature of 60° C. for 1 hour to obtain the carbon fiber fabric-based flexible electrode.

[0046] Performance testing:

[0047] The performance test of the carbon fiber fabric-based flexible electrode prepared in Example 1 was carried out, and the test results were as follows: the conductivity of the carbon fiber fabric-based flexible electrode was 500 S / m; at a current density of 1 mA / cm 2 When the area specific capacitance is 800mF / cm -2 , at 20mA / cm 2 At a current density of , the charge and discharge cycles were 10,000 times and the capacitance retention rate was 65%.

[0048] Example 2

[0049] This embodiment 2 provides a method for preparing a carbon fiber fabric-based flexible electrode, comprising the following steps:

[0050] Step 1: impregnate the carbon fiber fabric with a mixed acid solution and stir it in a water bath at 50°C for 4 hours. After stirring, wash it multiple times with a large amount of deionized water to obtain a pre-oxidized carbon fiber fabric; wherein the mixed acid solution is obtained by mixing concentrated nitric acid and concentrated sulfuric acid in a volume ratio of 1:4, the mass fraction of the concentrated nitric acid is 68%, and the mass fraction of the concentrated sulfuric acid is 98%.

[0051] Step 2: Add 10 mmol of Co(NO3)2·6H2O to deionized water and ultrasonically disperse it for 15 minutes to obtain a Co(NO3)2·6H2O solution with a concentration of 0.5 mmol / mL; add 20 mmol of 2-methylimidazole to deionized water and ultrasonically disperse it for 15 minutes to obtain a 2-methylimidazole solution with a concentration of 10 mmol / mL.

[0052] Step 3: Place 10 mmol of ammonium persulfate (APS) in an ice-water bath at 5°C and mechanically stir for 2 hours to obtain an APS solution; place 8 mmol of aniline monomer in an ice-water bath at 5°C and mechanically stir for 1.5 hours, and then disperse it in a 5 mol / L hydrochloric acid solution to obtain a 0.4 mmol / mL aniline acid solution.

[0053] Step 4: placing the pre-oxidized carbon fiber fabric in the Co(NO3)2·6H2O solution prepared in step 2, and performing vacuum impregnation for 4 hours at a vacuum degree of 0.1 MPa and a temperature of 100°C to obtain a vacuum-impregnated fabric; transferring the vacuum-impregnated fabric to the 2-methylimidazole solution prepared in step 2 to perform an in situ growth ZIF-L reaction for 4 hours. After the reaction is completed, the fabric is washed with deionized water and anhydrous ethanol several times, and dried in a blast drying oven at 80°C to obtain a ZIF-L modified carbon fiber fabric.

[0054] Step 5. Place the ZIF-L modified carbon fiber fabric in step 4 in the APS solution prepared in step 3, and immerse it at a temperature of 10°C for 3 hours to obtain an impregnated fabric; transfer the impregnated fabric to the aniline acid solution prepared in step 3, and perform an in situ redox reaction at 10°C for 4 hours to grow a conductive polymer polyaniline (PANI) on the surface of the ZIF-L modified carbon fiber fabric to obtain PANI@ZIF-L modified carbon fiber fabric.

[0055] Step 6: Place the PANI@ZIF-L modified carbon fiber fabric in step 5 in a vacuum drying oven and perform vacuum drying treatment at a vacuum degree of 0.09 MPa and a drying temperature of 100° C. for 10 hours to obtain the carbon fiber fabric-based flexible electrode.

[0056] Performance testing:

[0057] The performance test of the carbon fiber fabric-based flexible electrode prepared in Example 2 was carried out, and the test results were as follows: the conductivity of the carbon fiber fabric-based flexible electrode was 2200 S / m; at a current density of 1 mA / cm 2 When the area specific capacitance is 1800mF / cm -2 , at 20mA / cm 2 At a current density of , the charge and discharge cycles were 10,000 times and the capacitance retention rate was 85%.

[0058] Example 3

[0059] This embodiment 3 provides a method for preparing a carbon fiber fabric-based flexible electrode, comprising the following steps:

[0060] Step 1: impregnate the carbon fiber fabric with a mixed acid solution, stir it in a water bath at 40°C for 2.5 hours, and wash it multiple times with a large amount of deionized water to obtain a pre-oxidized carbon fiber fabric; wherein the mixed acid solution is obtained by mixing concentrated nitric acid and concentrated sulfuric acid in a volume ratio of 1:2, the mass fraction of the concentrated nitric acid is 65%, and the mass fraction of the concentrated sulfuric acid is 98%.

[0061] Step 2: Add 6 mmol of Co(NO3)2·6H2O to deionized water and ultrasonically disperse it for 10 minutes to obtain a Co(NO3)2·6H2O solution with a concentration of 0.3 mmol / mL; add 18 mmol of 2-methylimidazole to deionized water and ultrasonically disperse it for 10 minutes to obtain a 2-methylimidazole solution with a concentration of 9 mmol / mL.

[0062] Step 3: Place 9 mmol of ammonium persulfate (APS) in an ice-water bath at 3°C ​​and mechanically stir for 1.5 hours to obtain an APS solution; place 6 mmol of aniline monomer in an ice-water bath at 3°C ​​and mechanically stir for 1 hour, and then disperse it in a hydrochloric acid solution with a concentration of 3 mol / L to obtain an aniline acid solution with a concentration of 0.2 mmol / mL.

[0063] Step 4: placing the pre-oxidized carbon fiber fabric in the Co(NO3)2·6H2O solution prepared in step 2, and performing vacuum impregnation for 2.5 hours at a vacuum degree of 0.05 MPa and a temperature of 80°C to obtain a vacuum-impregnated fabric; transferring the vacuum-impregnated fabric to the 2-methylimidazole solution prepared in step 2 to perform an in situ growth ZIF-L reaction for 3 hours. After the reaction is completed, washing with deionized water and anhydrous ethanol several times, and drying in a blast drying oven at 70°C to obtain a ZIF-L modified carbon fiber fabric.

[0064] Step 5. Place the ZIF-L modified carbon fiber fabric in step 4 in the APS solution prepared in step 3, and immerse it at a temperature of 7°C for 2 hours to obtain an impregnated fabric; transfer the impregnated fabric to the aniline acid solution prepared in step 3, and perform an in situ redox reaction at 10°C for 4 hours to grow a conductive polymer polyaniline (PANI) on the surface of the ZIF-L modified carbon fiber fabric to obtain PANI@ZIF-L modified carbon fiber fabric.

[0065] Step 6: Place the PANI@ZIF-L modified carbon fiber fabric in step 5 in a vacuum drying oven and perform vacuum drying treatment at a vacuum degree of 0.05 MPa and a drying temperature of 60° C. for 5 hours to obtain the carbon fiber fabric-based flexible electrode.

[0066] Performance testing:

[0067] The performance test of the carbon fiber fabric-based flexible electrode prepared in Example 3 was carried out, and the test results were as follows: the conductivity of the carbon fiber fabric-based flexible electrode was 1700 S / m; at a current density of 1 mA / cm 2 When the area specific capacitance is 1500mF / cm -2 , at 20mA / cm 2 At a current density of , the charge and discharge cycles are 10,000 times and the capacitance retention rate is 70%.

[0068] Example 4

[0069] This embodiment 4 provides a method for preparing a carbon fiber fabric-based flexible electrode, comprising the following steps:

[0070] Step 1: impregnate the carbon fiber fabric with a mixed acid solution and stir it in a water bath at 35°C for 4 hours. After stirring, wash it multiple times with a large amount of deionized water to obtain a pre-oxidized carbon fiber fabric; wherein the mixed acid solution is obtained by mixing concentrated nitric acid and concentrated sulfuric acid in a volume ratio of 1:2, the mass fraction of the concentrated nitric acid is 68%, and the mass fraction of the concentrated sulfuric acid is 98%.

[0071] Step 2: Add 2 mmol of Co(NO3)2·6H2O to deionized water and ultrasonically disperse it for 15 minutes to obtain a Co(NO3)2·6H2O solution with a concentration of 0.1 mmol / mL; add 16 mmol of 2-methylimidazole to deionized water and ultrasonically disperse it for 15 minutes to obtain a 2-methylimidazole solution with a concentration of 8 mmol / mL.

[0072] Step 3: Place 7.5 mmol of ammonium persulfate (APS) in an ice-water bath at 0°C and mechanically stir for 2 hours to obtain an APS solution; place 3 mmol of aniline monomer in an ice-water bath at 0°C and mechanically stir for 1.5 hours, and then disperse it in a hydrochloric acid solution with a concentration of 1 mol / L to obtain an aniline acid solution with a concentration of 0.15 mmol / mL.

[0073] Step 4: placing the pre-oxidized carbon fiber fabric in the Co(NO3)2·6H2O solution prepared in step 2, and performing vacuum impregnation for 4 hours at a vacuum degree of 0.1 MPa and a temperature of 60°C to obtain a vacuum-impregnated fabric; transferring the vacuum-impregnated fabric to the 2-methylimidazole solution prepared in step 2, and performing an in situ growth ZIF-L reaction for 4 hours. After the reaction is completed, the fabric is washed with deionized water and anhydrous ethanol several times, and dried in a blast drying oven at 60°C to obtain a ZIF-L modified carbon fiber fabric.

[0074] Step 5. Place the ZIF-L modified carbon fiber fabric in step 4 in the APS solution prepared in step 3, and immerse it at a temperature of 4°C for 3 hours to obtain an impregnated fabric; transfer the impregnated fabric to the aniline acid solution prepared in step 3, and perform an in situ redox reaction at 4°C for 3 hours to grow a conductive polymer polyaniline (PANI) on the surface of the ZIF-L modified carbon fiber fabric to obtain PANI@ZIF-L modified carbon fiber fabric.

[0075] Step 6: Place the PANI@ZIF-L modified carbon fiber fabric in step 5 in a vacuum drying oven and perform vacuum drying treatment at a vacuum degree of 0.01 MPa and a drying temperature of 60° C. for 5 hours to obtain the carbon fiber fabric-based flexible electrode.

[0076] Performance testing:

[0077] The performance test of the carbon fiber fabric-based flexible electrode prepared in Example 4 was carried out, and the test results were as follows: the conductivity of the carbon fiber fabric-based flexible electrode was 2400 S / m; at a current density of 1 mA / cm 2 When the area specific capacitance is 2000mF / cm -2 , at 20mA / cm 2 At a current density of , the charge and discharge cycles are 10,000 times and the capacitance retention rate is 90%.

[0078] Example 5

[0079] This embodiment 5 provides a method for preparing a carbon fiber fabric-based flexible electrode, comprising the following steps:

[0080] Step 1: impregnate the carbon fiber fabric with a mixed acid solution and stir it in a water bath at 50°C for 4 hours. After stirring, wash it multiple times with a large amount of deionized water to obtain a pre-oxidized carbon fiber fabric; wherein the mixed acid solution is obtained by mixing concentrated nitric acid and concentrated sulfuric acid in a volume ratio of 1:2, the mass fraction of the concentrated nitric acid is 67%, and the mass fraction of the concentrated sulfuric acid is 97%.

[0081] Step 2: Add 2 mmol of Co(NO3)2·6H2O to deionized water and ultrasonically disperse for 5 minutes to obtain a Co(NO3)2·6H2O solution with a concentration of 0.1 mmol / mL; add 16 mmol of 2-methylimidazole to deionized water and ultrasonically disperse for 5 minutes to obtain a 2-methylimidazole solution with a concentration of 8 mmol / mL.

[0082] Step 3: Place 7.5 mmol of ammonium persulfate (APS) in an ice-water bath at 0°C and mechanically stir for 0.5 h to obtain an APS solution; place 3 mmol of aniline monomer in an ice-water bath at 0°C and mechanically stir for 0.5 h, then disperse in a 5 mol / L hydrochloric acid solution to obtain a 0.15 mmol / mL aniline acid solution.

[0083] Step 4: placing the pre-oxidized carbon fiber fabric in the Co(NO3)2·6H2O solution prepared in step 2, and performing vacuum impregnation for 4 hours at a vacuum degree of 0.01 MPa and a temperature of 60°C to obtain a vacuum-impregnated fabric; transferring the vacuum-impregnated fabric to the 2-methylimidazole solution prepared in step 2, and performing an in situ growth ZIF-L reaction for 4 hours. After the reaction, the fabric is washed with deionized water and anhydrous ethanol several times, and dried in a blast drying oven at 60°C to obtain a ZIF-L modified carbon fiber fabric.

[0084] Step 5. Place the ZIF-L modified carbon fiber fabric in step 4 in the APS solution prepared in step 3, and immerse it at a temperature of 4°C for 1 hour to obtain an impregnated fabric; transfer the impregnated fabric to the aniline acid solution prepared in step 3, and perform an in situ redox reaction at 4°C for 2 hours to grow a conductive polymer polyaniline (PANI) on the surface of the ZIF-L modified carbon fiber fabric to obtain PANI@ZIF-L modified carbon fiber fabric.

[0085] Step 6: Place the PANI@ZIF-L modified carbon fiber fabric in step 5 in a vacuum drying oven and perform vacuum drying treatment at a vacuum degree of 0.01 MPa and a drying temperature of 60° C. for 1 hour to obtain the carbon fiber fabric-based flexible electrode.

[0086] Performance testing:

[0087] The performance test of the carbon fiber fabric-based flexible electrode prepared in Example 5 was carried out, and the test results were as follows: the conductivity of the carbon fiber fabric-based flexible electrode was 1600 S / m; at a current density of 1 mA / cm 2 When the area specific capacitance is 1400mF / cm -2 , at 20mA / cm 2 At a current density of , the charge and discharge cycles were 10,000 times and the capacitance retention rate was 75%.

[0088] Example 6

[0089] This embodiment 6 provides a method for preparing a carbon fiber fabric-based flexible electrode, comprising the following steps:

[0090] Step 1: impregnate the carbon fiber fabric with a mixed acid solution and stir it in a water bath at 35°C for 4 hours. After stirring, wash it multiple times with a large amount of deionized water to obtain a pre-oxidized carbon fiber fabric; wherein the mixed acid solution is obtained by mixing concentrated nitric acid and concentrated sulfuric acid in a volume ratio of 1:2, the mass fraction of the concentrated nitric acid is 67%, and the mass fraction of the concentrated sulfuric acid is 98%.

[0091] Step 2: Add 2 mmol of Co(NO3)2·6H2O to deionized water and ultrasonically disperse for 5 minutes to obtain a Co(NO3)2·6H2O solution with a concentration of 0.1 mmol / mL; add 16 mmol of 2-methylimidazole to deionized water and ultrasonically disperse for 5 minutes to obtain a 2-methylimidazole solution with a concentration of 8 mmol / mL.

[0092] Step 3: Place 7.5 mmol of ammonium persulfate (APS) in an ice-water bath at 0°C and mechanically stir for 2 hours to obtain an APS solution; place 3 mmol of aniline monomer in an ice-water bath at 0°C and mechanically stir for 1.5 hours, and then disperse it in a hydrochloric acid solution with a concentration of 1 mol / L to obtain an aniline acid solution with a concentration of 0.15 mmol / mL.

[0093] Step 4: placing the pre-oxidized carbon fiber fabric in the Co(NO3)2·6H2O solution prepared in step 2, and performing vacuum impregnation for 4 hours at a vacuum degree of 0.1 MPa and a temperature of 60°C to obtain a vacuum-impregnated fabric; transferring the vacuum-impregnated fabric to the 2-methylimidazole solution prepared in step 2, and performing an in situ growth ZIF-L reaction for 4 hours. After the reaction is completed, the fabric is washed with deionized water and anhydrous ethanol several times, and dried in a blast drying oven at 60°C to obtain a ZIF-L modified carbon fiber fabric.

[0094] Step 5. Place the ZIF-L modified carbon fiber fabric in step 4 in the APS solution prepared in step 3, and immerse it at a temperature of 10°C for 1 hour to obtain an impregnated fabric; transfer the impregnated fabric to the aniline acid solution prepared in step 3, and perform an in situ redox reaction at 10°C for 2 hours to grow a conductive polymer polyaniline (PANI) on the surface of the ZIF-L modified carbon fiber fabric to obtain PANI@ZIF-L modified carbon fiber fabric.

[0095] Step 6: Place the PANI@ZIF-L modified carbon fiber fabric in step 5 in a vacuum drying oven and perform vacuum drying treatment at a vacuum degree of 0.01 MPa and a drying temperature of 60° C. for 1 hour to obtain the carbon fiber fabric-based flexible electrode.

[0096] Performance testing:

[0097] The performance test of the carbon fiber fabric-based flexible electrode prepared in Example 6 was carried out, and the test results were as follows: the conductivity of the carbon fiber fabric-based flexible electrode was 1650 S / m; at a current density of 1 mA / cm 2 When the area specific capacitance is 1500mF / cm -2 , at 20mA / cm 2 At a current density of , the charge and discharge cycles were 10,000 times and the capacitance retention rate was 82%.

[0098] As attached Figure 1-2 As shown, attached Figure 1 The SEM images of the carbon fiber fabric in Example 4 are given in FIG. Figure 2 The SEM images of ZIF-L modified carbon fiber fabrics in Example 4 are given in FIG. Figure 1 It can be seen from the figure that carbon fiber fabric is a three-dimensional network structure formed by interweaving carbon fibers. The surface of the carbon fiber is smooth when it is not treated, and the surface of the carbon fiber is inert. Figure 2 The carbon fiber surface becomes rough, indicating increased surface activity. Some functional groups are oxidized, allowing them to react with external compounds. Furthermore, the fiber surface is covered with a two-dimensional, leaf-like structure arranged in an array, demonstrating the successful loading of ZIF-L onto the carbon fiber surface. The metal-organic framework ZIF-L acts as an active material, providing capacity and a loading platform with a high specific surface area and porosity, ensuring rapid ion transfer and diffusion during charge and discharge, laying the foundation for the preparation of flexible electrodes with excellent mechanical properties, high electrochemical performance, and high cycle stability.

[0099] The carbon fiber fabric-based flexible electrode and preparation method described in the present invention, taking into account the requirements that energy storage materials should meet, are high specific capacity and low cost. Polyaniline, which has high specific capacitance, controllable conductivity, and low price, and the simple-to-prepare metal-organic framework ZIF-L are selected for compounding to improve the disadvantages of low capacitance and poor rate characteristics caused by the low conductivity of the metal-organic framework. The organic combination of the two makes the conductive polymer less likely to expand and collapse during long-term charging and discharging, thereby increasing the stability of the flexible energy storage material.

[0100] The above embodiment is only one of the implementation methods that can realize the technical solution of the present invention. The scope of protection claimed by the present invention is not limited only to this embodiment, but also includes changes, replacements and other implementation methods that can be easily thought of by any technician familiar with this technical field within the technical scope disclosed by the present invention.

Claims

1. A method for preparing a carbon fiber fabric-based flexible electrode, characterized in that: include: The carbon fiber fabric is subjected to oxidation treatment to obtain a pre-oxidized carbon fiber fabric; specifically, the carbon fiber fabric is immersed in a mixed acid solution, stirred in a water bath, and then washed to obtain the pre-oxidized carbon fiber fabric; wherein the mixed acid solution is a mixture of concentrated nitric acid and concentrated sulfuric acid; The pre-oxidized carbon fiber fabric is placed in a Co(NO3)2·6H2O solution for vacuum impregnation to obtain a vacuum-impregnated fabric; the vacuum-impregnated fabric is added to a 2-methylimidazole solution for in-situ growth of AIF-L, and after washing and drying, a ZIF-L modified carbon fiber fabric is obtained; The ZIF-L modified carbon fiber fabric is placed in an ammonium persulfate (APS) solution for impregnation to obtain an impregnated fabric; the impregnated fabric is added to an aniline solution for an in-situ redox reaction to obtain a PANI@ZIF-L modified carbon fiber fabric; The PANI@ZIF-L modified carbon fiber fabric is vacuum dried to obtain the carbon fiber fabric-based flexible electrode.

2. The method for preparing a carbon fiber fabric-based flexible electrode according to claim 1, characterized in that: The carbon fiber fabric is immersed in a mixed acid solution, stirred in a water bath and then washed to obtain a pre-oxidized carbon fiber fabric. The water bath stirring temperature is 35-50° C. and the stirring time is 1-4 hours.

3. The method for preparing a carbon fiber fabric-based flexible electrode according to claim 1, characterized in that: The pre-oxidized carbon fiber fabric is placed in a Co(NO3)2·6H2O solution for vacuum impregnation. In the process of obtaining the vacuum-impregnated fabric, the vacuum degree of the vacuum impregnation is 0.01-0.1 MPa and the temperature is 60-100°C; wherein the concentration of the Co(NO3)2·6H2O solution is 0.1-0.5 mmol / mL.

4. The method for preparing a carbon fiber fabric-based flexible electrode according to claim 1, characterized in that: The vacuum-impregnated fabric is added to a 2-methylimidazole solution to perform an in-situ AIF-L growth reaction. After washing and drying, the ZIF-L modified carbon fiber fabric is obtained. The in-situ AIF-L growth reaction time is 2-4 hours and the drying temperature is 60-80°C. The concentration of the 2-methylimidazole solution is 8-10 mmol / mL.

5. The method for preparing a carbon fiber fabric-based flexible electrode according to claim 1, characterized in that: The ZIF-L modified carbon fiber fabric is placed in an APS solution for impregnation. In the process of obtaining the impregnated fabric, the impregnation time is 1-3 hours and the temperature is 4-10°C.

6. The method for preparing a carbon fiber fabric-based flexible electrode according to claim 1, characterized in that: The impregnated fabric is added to an aniline acid solution to perform an in-situ redox reaction to obtain a PANI@ZIF-L modified carbon fiber fabric. The in-situ redox reaction lasts for 2-4 hours and the temperature is 4-10°C.

7. The method for preparing a carbon fiber fabric-based flexible electrode according to claim 1, characterized in that: During the vacuum drying process of the PANI@ZIF-L modified carbon fiber fabric, the drying temperature is 60-100° C., the drying time is 1-10 h, and the vacuum degree is 0.01-0.09 MPa.

8. A carbon fiber fabric-based flexible electrode, characterized in that: The flexible electrode is prepared by the method for preparing a carbon fiber fabric-based flexible electrode as described in any one of claims 1 to 7.

9. The carbon fiber fabric-based flexible electrode according to claim 8, characterized in that: The conductivity of the carbon fiber fabric-based flexible electrode is 500-2400S / cm; at a current density of 1mA / cm 2 When the area specific capacitance is 800-2000mF / cm -2 ; at 20mA / cm 2 At a current density of 10,000, the charge and discharge cycles are repeated 10,000 times, and the capacitance retention rate is 60-90%.

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