An integrated flexible supercapacitor and its preparation method

Abstract

The present invention provides an integrated flexible supercapacitor, which is a composite film formed by the composite of a perfluorosulfonic acid type proton exchange membrane and poly(3,4-ethylenedioxythiophene); the preparation method of the integrated flexible supercapacitor specifically includes: Step 1, proton exchange membrane etching, Step 2, proton exchange membrane swelling, and Step 3, composite film preparation. When preparing this flexible supercapacitor, there is no need to integrate additional current collectors, conductive additives, adhesives, etc., which can effectively simplify the preparation process of the flexible supercapacitor, improve the preparation efficiency, and save material costs.

Description

Technical Field

[0001] The present invention relates to the technical field of supercapacitors, and particularly relates to an integrated flexible supercapacitor and a preparation method thereof. Background Art

[0002] A supercapacitor, that is, a new energy storage device between a traditional capacitor and a rechargeable battery, has both the characteristics of rapid charge and discharge of a capacitor and the characteristics of high-efficiency energy storage of a battery. Compared with traditional storage batteries or physical capacitors, the characteristics of supercapacitors are mainly reflected in the following aspects: one is high power density, far higher than the power density level of storage batteries; the second is long cycle life; the third is wide operating temperature range; the fourth is high charge and discharge efficiency, having a certain tolerance to overcharge and over-discharge, and being able to charge and discharge stably and repeatedly; the fifth is not using heavy metals and other harmful substances, having a long self-life, and being green and environmentally friendly.

[0003] With the progress of technology and the rapid development of the electronics industry, flexible electronic devices with characteristics such as portability and wearability are gradually entering people's lives and influencing people's lives. Therefore, the research and development of energy storage devices with high capacity, small volume, and flexible characteristics that match them has become one of the current research hotspots. As a new energy storage device, the flexible solid-state supercapacitor not only has advantages such as high capacity, rapid charge and discharge, long cycle life, safety and environmental protection, but also has good deformation, bending, and stretching capabilities. In addition, the flexible solid-state supercapacitor can support a smaller size, so it is convenient to be prepared on flexible, stretchable, and even wearable substrates by a simple method to meet the needs of portable and wearable electronic devices.

[0004] However, when constructing traditional supercapacitors, various substances such as current collectors, conductive additives, active materials, adhesives, electrolytes, separators, and solvents are often required, resulting in an increase in their material costs and a relatively complex overall structure. At the same time, it also leads to complex preparation processes and low preparation efficiency. Summary of the Invention

[0005] Aiming at the problems existing in the above prior art, the purpose of the present invention is to provide an integrated flexible supercapacitor, which does not require the integration of additional current collectors, conductive additives, adhesives, etc. during preparation, thereby effectively simplifying the preparation process of the flexible supercapacitor, improving the preparation efficiency, and saving material costs.

[0006] Another purpose of the present invention is a preparation method of the above integrated flexible supercapacitor.

[0007] The purpose of the present invention is achieved by the following technical solutions:

[0008] An integrated flexible supercapacitor, characterized in that: it is a composite film composed of a perfluorosulfonic acid type proton exchange membrane and poly(3,4-ethylenedioxythiophene).

[0009] For further optimization, the thickness of the perfluorosulfonic acid type proton exchange membrane is 50 - 250 μm.

[0010] The preparation method of the above integrated flexible supercapacitor, characterized in that: specifically includes the following steps:

[0011] Step 1, proton exchange membrane etching: First, cut the perfluorosulfonic acid type proton exchange membrane into a rectangle, and put the cut perfluorosulfonic acid type proton exchange membrane into the chamber of a magnetron sputtering instrument, using the perfluorosulfonic acid type proton exchange membrane as the cathode target; then, start the magnetron sputtering instrument, and use the plasma generated in the chamber of the magnetron sputtering instrument to etch the perfluorosulfonic acid type proton exchange membrane used as the cathode target; after etching T for 1 hour, a nanoporous structure is generated on the perfluorosulfonic acid type proton exchange membrane, and turn off the magnetron sputtering instrument;

[0012] Step 2, proton exchange membrane swelling: Immerse the perfluorosulfonic acid type proton exchange membrane etched in Step 1 in 3,4-ethylenedioxythiophene liquid, T after 2 hours, the perfluorosulfonic acid type proton exchange membrane is fully swollen, take out the perfluorosulfonic acid type proton exchange membrane, and use a dry paper towel to absorb the free liquid droplets on the surface of the perfluorosulfonic acid type proton exchange membrane;

[0013] Step 3, composite film preparation: Immerse the perfluorosulfonic acid type proton exchange membrane obtained in Step 2 into FeCl 3 aqueous solution, T 3 after a certain time, take out the perfluorosulfonic acid type proton exchange membrane to obtain a composite film composed of the perfluorosulfonic acid type proton exchange membrane and poly(3,4-ethylenedioxythiophene).

[0014] For further optimization, the starting power of the magnetron sputtering instrument in Step 1 is 780 - 820 W; the T 1 is 0.6 - 1.5 h.

[0015] For further optimization, during the etching process of the magnetron sputtering instrument in Step 1, the temperature of the perfluorosulfonic acid type proton exchange membrane is 30 - 100 °C.

[0016] For further optimization, the T 2 is 3.5 - 4.5 h.

[0017] For further optimization, the FeCl 3 concentration of the aqueous solution is 3.8 - 4.2 mol / L; the T3 is 1.8 - 2.2 h.

[0018] For further optimization, after obtaining the composite film composed of the perfluorosulfonic acid type proton exchange membrane and poly(3,4 - ethylenedioxythiophene) in the third step, the four sides of the composite film are trimmed, that is, a small part is cut off from each side, so as to prevent short - circuit, and the integrated flexible supercapacitor is obtained.

[0019] The usage method of the above - mentioned integrated flexible supercapacitor is characterized in that: the integrated flexible supercapacitor is directly installed on portable, wearable and other electronic devices and used as a flexible energy storage element.

[0020] Since the surface of the perfluorosulfonic acid type proton exchange membrane is smooth, if the perfluorosulfonic acid type proton exchange membrane and 3,4 - ethylenedioxythiophene are directly subjected to swelling adsorption, the content of 3,4 - ethylenedioxythiophene adsorbed by the perfluorosulfonic acid type proton exchange membrane is less, directly resulting in low content of poly(3,4 - ethylenedioxythiophene) in the subsequent preparation, poor conductivity, and insecure deposition, which affects the electrochemical energy storage properties of the components; in this application, the perfluorosulfonic acid type proton exchange membrane is used as the cathode target in a magnetron sputtering instrument for T etching at time 1, so as to etch and form a rich and uniform nanoporous structure on the surface of the perfluorosulfonic acid type proton exchange membrane, that is, the pore depth is moderate, avoiding the problem of less content of adsorbed and swollen 3,4 - ethylenedioxythiophene caused by only cracks or shallow pores on the surface of the proton exchange membrane, or avoiding the problem of serious damage to the surface of the proton exchange membrane and collapse of the nanoporous channels caused by deeper etching; at the same time, through magnetron sputtering etching and dry tissue adsorption treatment, the problem of uneven and loose poly(3,4 - ethylenedioxythiophene) layer caused by the prior polymerization of free 3,4 - ethylenedioxythiophene on the surface of the proton exchange membrane is avoided, ensuring the bonding strength between the poly(3,4 - ethylenedioxythiophene) layer and the proton exchange membrane and avoiding the peeling of the poly(3,4 - ethylenedioxythiophene) layer from the surface of the proton exchange membrane; after the proton exchange membrane adsorbs and swells 3,4 - ethylenedioxythiophene, poly(3,4 - ethylenedioxythiophene) nanoparticles are generated by in - situ oxidation of 3,4 - ethylenedioxythiophene, effectively improving the bonding strength between the poly(3,4 - ethylenedioxythiophene) nanoparticles and the proton exchange membrane, ensuring the stable composite of the proton exchange membrane and the poly(3,4 - ethylenedioxythiophene) nanoparticles, and guaranteeing the overall performance of the composite film. The poly(3,4 - ethylenedioxythiophene) nanoparticles not only fill into the nanoporous channels of the proton exchange membrane, but also stack and adhere to form a continuous conductive layer covering the surface of the proton membrane, improving the overall electrochemical properties of the composite film.

[0021] The present invention has the following technical effects:

[0022] In this application, a perfluorosulfonic acid-based proton exchange membrane is adopted, which is used as a separator to isolate the positive and negative electrodes and also acts as an electrolyte. Moreover, there is no need to additionally adopt current collectors, conductive additives, adhesives, etc., thus effectively reducing the components of the supercapacitor and making the assembly more convenient and efficient. At the same time, the proton exchange membrane etched by a magnetron sputtering instrument is used to swell and adsorb 3,4-ethylenedioxythiophene, and then an in-situ oxidative polymerization is carried out using a solution containing ferric ions, so as to generate a poly(3,4-ethylenedioxythiophene) layer that is stacked, adhered, and filled with each other on the proton exchange membrane as a conductive polymer. On the premise of ensuring the tight combination of the conductive polymer and the proton exchange membrane, the utilization rate of the conductive polymer and the electrochemical properties of the composite film are ensured, effectively avoiding problems such as the shedding of the poly(3,4-ethylenedioxythiophene) layer and the collapse of the pore channels on the surface of the proton exchange membrane. At the same time, this application does not require the use of an electrolyte, effectively avoiding the problem of electrolyte leakage when the flexible capacitor is bent. In addition, through the composite of the perfluorosulfonic acid-based proton exchange membrane and the poly(3,4-ethylenedioxythiophene) layer, the preparation steps are simple and the time-consuming is short, which can effectively save the preparation process and reduce the material cost.

[0023] Furthermore, the integrated flexible supercapacitor of this application has excellent charge storage capacity. For example, the areal specific capacitance can be as high as 190.2 mF / cm 2 , and the rate performance and cycle stability are also quite outstanding. Even after continuous charge and discharge 5000 times at a relatively high current density, the capacitance retention rate is still 91.2%. Moreover, the integrated flexible supercapacitor of this application has good flexibility, and the electrochemical energy storage behavior is hardly affected in the bent state. These electrochemical properties are superior to those of many flexible supercapacitors based on carbon cloth, MXene film, and graphene film.

[0024] Therefore, in terms of device structure, preparation process, and energy storage effect, etc., the integrated flexible supercapacitor of this application is suitable for large-scale production, can be effectively applied to various portable and wearable electronic devices, has a wide application range, and has good energy storage advantages and bright application prospects. Description of the Drawings

[0025] Figure 1 Scanning electron microscope images of the original perfluorosulfonic acid-based proton exchange membrane at different magnifications (i.e., 1μm and 200nm).

[0026] Figure 2 Scanning electron microscope images of the perfluorosulfonic acid-based proton exchange membrane in Example 2 of this application at different magnifications (i.e., 2μm and 1μm).

[0027] Figure 3 Scanning electron microscope images of the perfluorosulfonic acid-based proton exchange membrane in Comparative Example 1 at different magnifications (i.e., 1μm and 200nm).

[0028] Figure 4 is a scanning electron micrograph of the perfluorosulfonic acid-based proton exchange membrane in Comparative Example 2 at different magnifications (i.e., 2 μm and 1 μm).

[0029] Figure 5 This is an electron photograph of the integrated flexible supercapacitor in Example 2 of this application in the natural state and the bent state.

[0030] Figure 6 This is a scanning electron micrograph of the integrated flexible supercapacitor in Example 2 of this application at different magnifications (i.e., 1 μm and 200 nm).

[0031] Figure 7 This is a cyclic voltammogram of the integrated flexible supercapacitor in Example 2 of this application at different scan rates.

[0032] Figure 8 This is a charge-discharge curve of the integrated flexible supercapacitor in Example 2 of this application at different current densities.

[0033] Figure 9 This is a graph showing the relationship between the specific capacitance and the current density of the integrated flexible supercapacitor in Example 2 of this application.

[0034] Figure 10 This is a graph showing the relationship between the capacitance retention rate and the number of charge-discharge cycles of the integrated flexible supercapacitor in Example 2 of this application.

[0035] Figure 11 This is a cyclic voltammogram of the integrated flexible supercapacitor in Example 2 of this application in the natural state and the bent state.

[0036] Figure 12 This is a charge-discharge curve of the integrated flexible supercapacitor in Example 2 of this application in the natural state and the bent state. Embodiment

[0037] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention. Example

[0038] An integrated flexible supercapacitor, characterized in that: it is a composite film formed by the composite of a perfluorosulfonic acid-based proton exchange membrane and poly(3,4-ethylenedioxythiophene); wherein, the thickness of the perfluorosulfonic acid-based proton exchange membrane is 50 μm (a common perfluorosulfonic acid-based proton exchange membrane in the art can be used for the perfluorosulfonic acid-based proton exchange membrane).

[0039] The preparation of the integrated flexible supercapacitor specifically includes the following steps:

[0040] Step 1, proton exchange membrane etching: First, the perfluorosulfonic acid proton exchange membrane is cut into a rectangle (the size of the rectangle is cut according to specific needs), and the cut perfluorosulfonic acid proton exchange membrane is placed in the chamber of a magnetron sputtering instrument, with the perfluorosulfonic acid proton exchange membrane as a cathode target; then, the magnetron sputtering instrument is started, and the starting power of the magnetron sputtering instrument is 780W. The plasma generated in the chamber of the magnetron sputtering instrument is used to etch the perfluorosulfonic acid proton exchange membrane as the cathode target, and the temperature of the perfluorosulfonic acid proton exchange membrane is maintained at 30°C during the etching process; after etching for 0.6h, the perfluorosulfonic acid proton exchange membrane generates a nanopore structure, and the magnetron sputtering instrument is turned off;

[0041] Step 2, swelling of the proton exchange membrane: immerse the perfluorosulfonic acid proton exchange membrane etched in step 1 in 3,4-ethylenedioxythiophene liquid (the 3,4-ethylenedioxythiophene liquid commonly available on the market in this field can be used). After 3.5 hours, the perfluorosulfonic acid proton exchange membrane is fully swollen, and the perfluorosulfonic acid proton exchange membrane is taken out, and the free droplets on the surface of the perfluorosulfonic acid proton exchange membrane are dried with a dry paper towel (the drying standard is: no droplets fall from the surface of the perfluorosulfonic acid proton exchange membrane when observed with the naked eye);

[0042] Step 3: Preparation of composite film: Immerse the perfluorosulfonic acid proton exchange membrane obtained in step 2 into FeCl 3 In aqueous solution, FeCl 3 The concentration of the aqueous solution is 3.8 mol / L. After 1.8 hours, the perfluorosulfonic acid proton exchange membrane is taken out to obtain a composite film composed of the perfluorosulfonic acid proton exchange membrane and poly (3,4-ethylenedioxythiophene).

[0043] Step 4: Preparation of an integrated flexible supercapacitor: The four sides of the composite film obtained in step 3 are cut, that is, a small portion of each side is cut off to prevent short circuit, thereby obtaining an integrated flexible supercapacitor. Example

[0044] An integrated flexible supercapacitor is characterized in that it is a composite film composed of a perfluorosulfonic acid proton exchange membrane and poly (3,4-ethylenedioxythiophene); wherein the thickness of the perfluorosulfonic acid proton exchange membrane is 150 μm (the perfluorosulfonic acid proton exchange membrane can be the perfluorosulfonic acid proton exchange membrane commonly used in the art).

[0045] The preparation of the integrated flexible supercapacitor specifically includes the following steps:

[0046] Step 1, proton exchange membrane etching: First, the perfluorosulfonic acid proton exchange membrane is cut into a rectangle (the size of the rectangle is cut according to specific needs), and the cut perfluorosulfonic acid proton exchange membrane is placed in the chamber of a magnetron sputtering instrument, with the perfluorosulfonic acid proton exchange membrane as a cathode target; then, the magnetron sputtering instrument is started, and the starting power of the magnetron sputtering instrument is 800W. The plasma generated in the chamber of the magnetron sputtering instrument is used to etch the perfluorosulfonic acid proton exchange membrane as the cathode target, and the temperature of the perfluorosulfonic acid proton exchange membrane is maintained at 40°C during the etching process; after etching for 1 hour, the perfluorosulfonic acid proton exchange membrane generates a nanopore structure, and the magnetron sputtering instrument is turned off;

[0047] Step 2, swelling of the proton exchange membrane: immerse the etched perfluorosulfonic acid proton exchange membrane in step 1 in 3,4-ethylenedioxythiophene liquid (the 3,4-ethylenedioxythiophene liquid commonly available on the market in this field can be used). After 4 hours, the perfluorosulfonic acid proton exchange membrane is fully swollen, and the perfluorosulfonic acid proton exchange membrane is taken out, and the free droplets on the surface of the perfluorosulfonic acid proton exchange membrane are dried with a dry paper towel (the drying standard is: no droplets fall from the surface of the perfluorosulfonic acid proton exchange membrane when observed with the naked eye);

[0048] Step 3: Preparation of composite film: Immerse the perfluorosulfonic acid proton exchange membrane obtained in step 2 into FeCl 3 In aqueous solution, FeCl 3 The concentration of the aqueous solution is 4 mol / L. After 2 hours, the perfluorosulfonic acid proton exchange membrane is taken out to obtain a composite film consisting of the perfluorosulfonic acid proton exchange membrane and poly (3,4-ethylenedioxythiophene).

[0049] Step 4: Preparation of an integrated flexible supercapacitor: The four sides of the composite film obtained in step 3 are cut, that is, a small portion of each side is cut off to prevent short circuit, thereby obtaining an integrated flexible supercapacitor. Example

[0050] An integrated flexible supercapacitor is characterized in that it is a composite film composed of a perfluorosulfonic acid proton exchange membrane and poly (3,4-ethylenedioxythiophene); wherein the thickness of the perfluorosulfonic acid proton exchange membrane is 250 μm (the perfluorosulfonic acid proton exchange membrane can be a perfluorosulfonic acid proton exchange membrane commonly used in the art).

[0051] The preparation of the integrated flexible supercapacitor specifically includes the following steps:

[0052] Step 1, proton exchange membrane etching: First, the perfluorosulfonic acid proton exchange membrane is cut into a rectangle (the size of the rectangle is cut according to specific needs), and the cut perfluorosulfonic acid proton exchange membrane is placed in the chamber of a magnetron sputtering instrument, with the perfluorosulfonic acid proton exchange membrane as a cathode target; then, the magnetron sputtering instrument is started, and the starting power of the magnetron sputtering instrument is 820W. The plasma generated in the chamber of the magnetron sputtering instrument is used to etch the perfluorosulfonic acid proton exchange membrane as the cathode target, and the temperature of the perfluorosulfonic acid proton exchange membrane is maintained at 100°C during the etching process; after etching for 1.5 hours, the perfluorosulfonic acid proton exchange membrane generates a nanopore structure, and the magnetron sputtering instrument is turned off;

[0053] Step 2, swelling of the proton exchange membrane: immerse the etched perfluorosulfonic acid proton exchange membrane in step 1 in 3,4-ethylenedioxythiophene liquid (the 3,4-ethylenedioxythiophene liquid commonly available on the market can be used). After 4.5 hours, the perfluorosulfonic acid proton exchange membrane is fully swollen. The perfluorosulfonic acid proton exchange membrane is taken out, and the free droplets on the surface of the perfluorosulfonic acid proton exchange membrane are dried with a dry paper towel (the drying standard is: no droplets fall from the surface of the perfluorosulfonic acid proton exchange membrane when observed with the naked eye);

[0054] Step 3: Preparation of composite film: Immerse the perfluorosulfonic acid proton exchange membrane obtained in step 2 into FeCl 3 In aqueous solution, FeCl 3 The concentration of the aqueous solution is 4.2 mol / L. After 2.2 hours, the perfluorosulfonic acid proton exchange membrane is taken out to obtain a composite film composed of the perfluorosulfonic acid proton exchange membrane and poly (3,4-ethylenedioxythiophene).

[0055] Step 4: Preparation of an integrated flexible supercapacitor: The four sides of the composite film obtained in step 3 are cut, that is, a small portion of each side is cut off to prevent short circuit, thereby obtaining an integrated flexible supercapacitor. Example

[0056] The method for using the integrated flexible supercapacitor in the above-mentioned embodiments 1 to 3 is characterized in that the integrated flexible supercapacitor is directly installed on portable, wearable and other electronic devices and used as a flexible energy storage element.

[0057] Proton exchange membrane etching: First, a perfluorosulfonic acid type proton exchange membrane with a thickness of 150 μm (the perfluorosulfonic acid type proton exchange membrane is the same as that in Example 2) is cut into a rectangle (the size of the rectangle is cut according to specific requirements), and the cut perfluorosulfonic acid type proton exchange membrane is placed in the chamber of a magnetron sputtering instrument, with the perfluorosulfonic acid type proton exchange membrane as the cathode target; then, the magnetron sputtering instrument is started, the starting power of the magnetron sputtering instrument is 800 W, and the perfluorosulfonic acid type proton exchange membrane used as the cathode target is etched by the plasma generated in the chamber of the magnetron sputtering instrument. During the etching process, the temperature of the perfluorosulfonic acid type proton exchange membrane is maintained at 25 °C; after etching for 0.5 h, a nanoporous structure is generated on the perfluorosulfonic acid type proton exchange membrane, and the magnetron sputtering instrument is turned off and the proton exchange membrane is taken out.

[0058] Proton exchange membrane etching: First, a perfluorosulfonic acid type proton exchange membrane with a thickness of 150 μm (the perfluorosulfonic acid type proton exchange membrane is the same as that in Example 2) is cut into a rectangle (the size of the rectangle is cut according to specific requirements), and the cut perfluorosulfonic acid type proton exchange membrane is placed in the chamber of a magnetron sputtering instrument, with the perfluorosulfonic acid type proton exchange membrane as the cathode target; then, the magnetron sputtering instrument is started, the starting power of the magnetron sputtering instrument is 800 W, and the perfluorosulfonic acid type proton exchange membrane used as the cathode target is etched by the plasma generated in the chamber of the magnetron sputtering instrument. During the etching process, the temperature of the perfluorosulfonic acid type proton exchange membrane is maintained at 105 °C; after etching for 1.6 h, a nanoporous structure is generated on the perfluorosulfonic acid type proton exchange membrane, and the magnetron sputtering instrument is turned off and the proton exchange membrane is taken out.

[0059] The unetched proton exchange membrane and the etched proton exchange membranes in Example 2, Comparative Example 1, and Comparative Example 2 are respectively placed under electron microscopes with different magnifications for scanning, and the scanning images are respectively as Figure 1 , Figure 2 , Figure 3 , Figure 4 shown; it can be seen that: the surface of the unetched proton exchange membrane is flat and smooth, the nanoporous structure on the surface of the proton exchange membrane etched in Example 2 becomes uniform and rich, and the pore depth is moderate. Only many shallow cracks are generated on the surface of the proton exchange membrane etched in Comparative Example 1. The nanoporous structure on the surface of the proton exchange membrane etched in Comparative Example 2 has collapsed, indicating that the time of the etching process and the temperature of the proton exchange membrane are very important for the formation of nanopores.

[0060] Figure 5 are the electron photos of the integrated flexible supercapacitor in Example 2 in the natural state and the bent state. It can be clearly seen from Figure 5 that: after the etched perfluorosulfonic acid type proton exchange membrane is compounded with poly(3,4-ethylenedioxythiophene), the surface of the obtained integrated flexible supercapacitor composite film becomes black, and at the same time, it has good flexibility; Figure 6It is the scanning electron microscope image of the integrated flexible supercapacitor in Example 2 at different magnification ratios (i.e., 1μm and 200nm). It can be seen from Figure 6 that the poly(3,4-ethylenedioxythiophene) layer is composed of nanoparticles of this component stacked and adhered to each other, and is tightly combined and firmly compounded with the substrate perfluorosulfonic acid type proton exchange membrane.

[0061] The integrated flexible supercapacitor in Example 2 was further used for electrochemical energy storage tests in a two-electrode system:

[0062] First, the cyclic voltammetry performance of this integrated flexible supercapacitor was tested. As Figure 7 shown: This device has a large output potential difference (0 - 1 V), and the cyclic voltammograms at different scan rates all show a quasi-rectangular shape, indicating its excellent electrochemical activity and reversibility. Figure 8 is the galvanostatic charge-discharge curve diagram of it at a series of current densities. According to the data recorded in the figure and relevant formulas, the specific capacitances of this device at (2, 5, 10, 20, 30, and 40) mA / cm 2 current densities are (190.2, 162.6, 144.7, 128.6, 117, and 108.8) mF / cm 2 . These data were further plotted into a dotted line graph as Figure 9 shown. It is worth mentioning that at a small current density of 2 mA / cm 2 , its maximum specific capacitance, that is, 190.2 mF / cm 2 can exceed the maximum specific capacitances of many flexible supercapacitors based on carbon cloth, MXene thin films, and graphene thin films; in addition, the specific capacitance of this integrated flexible supercapacitor at a high current density of 40 mA / cm 2 is still quite considerable, reaching 108.8 mF / cm 2 , which is equivalent to 57.2% of its maximum specific capacitance, showing excellent rate performance. To test the cycling stability of this device, the device was continuously charged and discharged 5000 times at a high current density of 40 mA / cm 2 . It can be clearly seen from Figure 12 that the specific capacitance decay of the device is relatively slow throughout the process, and there is still a capacitance retention rate of 91.2% after the test. Such performance is also superior to the charge-discharge stability of most currently reported integrated flexible supercapacitors. In addition, this device also shows excellent anti-bending ability. As Figure 11 and Figure 12 shown, the CV curves and GCD curves of this integrated flexible supercapacitor in the natural and bent states can almost coincide, indicating that bending has little effect on its electrochemical energy storage behavior.

[0063] The above electrochemical test results reflect that the integrated flexible supercapacitor prepared in Example 2 has outstanding energy storage advantages and development potential, and thus is expected to have practical applications in frontier fields such as flexible electronics and wearable devices.

[0064] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An integrated flexible supercapacitor, characterized in that: It is a composite film composed of a perfluorosulfonic acid type proton exchange membrane and poly(3,4-ethylenedioxythiophene); the preparation steps of the composite film specifically include: Step 1. Proton exchange membrane etching: First, cut the perfluorosulfonic acid type proton exchange membrane into a rectangle, and place the cut perfluorosulfonic acid type proton exchange membrane into the chamber of a magnetron sputtering instrument, using the perfluorosulfonic acid type proton exchange membrane as the cathode target; then, start the magnetron sputtering instrument, and use the plasma generated in the chamber of the magnetron sputtering instrument to etch the perfluorosulfonic acid type proton exchange membrane used as the cathode target; after etching T for 1 hour, a nanoporous structure is generated on the perfluorosulfonic acid type proton exchange membrane, and turn off the magnetron sputtering instrument; Step 2: Proton exchange membrane swelling: immerse the perfluorosulfonic acid type proton exchange membrane etched in step 1 in 3,4-ethylenedioxythiophene liquid. T After 2 hours, the perfluorosulfonic acid type proton exchange membrane is fully swollen, and the perfluorosulfonic acid type proton exchange membrane is taken out, and the free droplets on the surface of the perfluorosulfonic acid type proton exchange membrane are dried with a dry paper towel; Step 3. Preparation of composite film: Immerse the perfluorosulfonic acid type proton exchange membrane obtained in Step 2 into FeCl 3 aqueous solution, T After 3 hours, take out the perfluorosulfonic acid type proton exchange membrane to obtain a composite film composed of the perfluorosulfonic acid type proton exchange membrane and poly(3,4-ethylenedioxythiophene).

2. The integrated flexible supercapacitor according to claim 1, characterized in that: The thickness of the perfluorosulfonic acid type proton exchange membrane is 50 to 250 μm.

3. The preparation method of an integrated flexible supercapacitor according to claim 1, characterized in that: In the first step, the starting power of the magnetron sputtering instrument is 780 - 820 W; the T 1 is 0.6 - 1.5 h.

4. The preparation method of an integrated flexible supercapacitor according to claim 1, characterized in that: The said T 2 is 3.5 to 4.5 h.

5. The preparation method of an integrated flexible supercapacitor according to claim 1, wherein: After obtaining the composite film composed of the perfluorosulfonic acid type proton exchange membrane and poly(3,4-ethylenedioxythiophene) in the third step, the four sides of the composite film are also cut, that is, a small part is cut off from each side, so as to prevent short circuit, and then the integrated flexible supercapacitor is obtained.

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