Preparation method of ultrahigh-magnification and high-energy-density aqueous supercapacitor

Abstract

The application discloses a preparation method of an ultrahigh-multiplying high-energy-density water-based supercapacitor, and relates to the technical field of supercapacitors. x The preparation method comprises the following steps: step 1, preparing small-size graphene two-dimensional nanosheets; step 2, preparing small-size Ti3C2T x The preparation method comprises the following steps: step 1, preparing small-size graphene two-dimensional nanosheets; step 2, preparing small-size Ti3C2T x The preparation method comprises the following steps: step 1, preparing small-size graphene two-dimensional nanosheets; step 2, preparing small-size Ti3C2T x The preparation method comprises the following steps: step 1, preparing small-size graphene two-dimensional nanosheets; step 2, preparing small-size Ti3C2T The small-size two-dimensional nanosheets are used as electrode materials, the positive and negative electrode materials are selected, the open-circuit potentials of the positive and negative electrodes are adjusted, the capacities and masses of the positive and negative electrodes are matched, and thus the obtained supercapacitor can exhibit high energy density under ultrahigh multiplying.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of supercapacitors, and particularly relates to a preparation method of a super-high-rate and high-energy-density aqueous supercapacitor. BACKGROUND

[0002] Supercapacitors are one of the most important electrochemical energy storage devices, with high power density and long cycle life, which can meet the needs of short-time and frequent charge-discharge application scenarios (such as grid peak shaving, braking energy regeneration, etc.), and are an effective supplement to metal-ion batteries (high energy density, low power density). The currently commercially used supercapacitors are mainly organic supercapacitors based on activated carbon electrodes, which can achieve tens of seconds to minutes of charge-discharge, but it is difficult to achieve super-high-rate (3.6s charge-discharge, greater than 1,000C) energy storage and release, and cannot meet the needs of energy burst scenarios. In addition, the manufacture and service environment of organic supercapacitors are harsh, which requires strict control of moisture during preparation and strict sealing, and the organic solvent of the electrolyte is volatile, flammable, explosive, toxic and high in cost.

[0003] Aqueous electrolyte has smaller cation size and higher ionic conductivity (up to 1.0S / cm), so using it as the electrolyte of supercapacitors can achieve faster charge-discharge speed and higher capacitance, and is more likely to achieve super-fast supercapacitors. In addition, aqueous electrolyte is green, non-toxic, safe and low in cost, and is more suitable for practical application than organic electrolyte. However, the device of aqueous supercapacitors is limited by the narrow electrochemical stability window (1.23V) of aqueous electrolyte, and it is difficult to achieve high voltage and high energy density, and it is difficult to meet the needs of practical application.

[0004] Two-dimensional nanosheet material has high electronic and ionic conductivity and high theoretical specific surface area, and is an ideal supercapacitor electrode material. To achieve super-high-rate supercapacitors, the ion transport channel inside the electrode needs to be carefully designed to enable the electrode with high active material surface loading to achieve super-high-rate charge-discharge. The current research mainly focuses on electrodes based on two-dimensional nanosheets with micron-level lateral size, but the internal ion transport channel is long and it is difficult to achieve super-high-rate charge-discharge. However, the use of small-size two-dimensional nanosheets can significantly reduce the lateral ion transport distance and increase the number of vertical ion transport channels, thereby significantly improving the super-high-rate charge-discharge capability. In addition, by matching the positive and negative electrode materials, an asymmetric supercapacitor device can be constructed to fully utilize its stable voltage window to achieve high voltage and high energy density.

[0005] At present, the research on the preparation of super-high-rate (greater than 1,000C) supercapacitors is still limited by extremely low energy density, which cannot meet the needs of practical application, and solving this problem has important theoretical and practical significance.

[0006] Therefore, the person skilled in the art is committed to developing a preparation method of a superhigh-rate and high-energy-density aqueous supercapacitor, which can exhibit high energy density under superhigh rate. SUMMARY

[0007] In view of the above defects of the prior art, the technical problem to be solved by the present application is how to enable the supercapacitor to work under superhigh rate.

[0008] To achieve the above-mentioned purpose, the present application provides a preparation method of a superhigh-rate and high-energy-density aqueous supercapacitor, which comprises the following steps:

[0009] Step 1, preparing small-size graphene two-dimensional nanosheets;

[0010] Step 2, preparing small-size Ti3C2T x two-dimensional nanosheets;

[0011] Step 3, preparing small-size graphene hydration film and small-size Ti3C2T x hydration film, the small-size graphene hydration film as a positive electrode, and the small-size Ti3C2T x hydration film as a negative electrode;

[0012] Step 4, separating the small-size graphene two-dimensional nanosheet hydration film and the small-size Ti3C2T x two-dimensional nanosheet hydration film by a separator, and then injecting electrolyte to realize the assembly of the aqueous supercapacitor.

[0013] Further, the step 1 further comprises:

[0014] Step 1.1, preparing large-size graphene two-dimensional nanosheets;

[0015] Step 1.2, obtaining small-size graphene two-dimensional nanosheets by probe ultrasonic and centrifugal purification.

[0016] Further, in the step 1.1, the large-size graphene two-dimensional nanosheets are large-size reduced graphene oxide two-dimensional nanosheets or large-size electrochemically exfoliated graphene two-dimensional nanosheets.

[0017] Further, the preparation method of the large-size reduced graphene oxide two-dimensional nanosheets comprises: obtaining large-size graphene oxide two-dimensional nanosheets by oxidizing flake graphite by Hummer’s method, and then reducing the large-size graphene oxide two-dimensional nanosheets to obtain large-size reduced graphene oxide two-dimensional nanosheets;

[0018] Further, the preparation method of the large-size electrochemically exfoliated graphene two-dimensional nanosheet comprises the following steps: using 0.1M (NH4) 2SO4 aqueous solution as an electrolyte, using graphite paper and platinum mesh as an anode and a cathode respectively, and using a direct current power supply to apply a voltage of 10V to graphite to obtain a large-size electrochemically exfoliated graphene two-dimensional nanosheet.

[0019] Further, the step 2 further comprises:

[0020] Step 2.1, etching to prepare a large-size Ti3C2T x two-dimensional nanosheet by using a LiF / HCl method.

[0021] Step 2.2, obtaining a small-size Ti3C2T x two-dimensional nanosheet by probe ultrasonic and centrifugal purification.

[0022] Further, the step 3 further comprises: using a suction filtration device with a diameter of 38mm, adding a small-size graphene two-dimensional nanosheet or a small-size Ti3C2T x two-dimensional nanosheet suspension containing 60mg on the surface of a microporous filter membrane, and stopping immediately after vacuum suction filtration until the liquid disappears, so as to obtain a small-size graphene two-dimensional nanosheet hydration film and a small-size Ti3C2T x two-dimensional nanosheet hydration film respectively, wherein the nanosheet in the film is arranged in parallel to the surface.

[0023] Further, the diaphragm is a glass fiber filter membrane.

[0024] Further, the electrolyte is H2SO4.

[0025] Further, the open circuit potential of the anode and the cathode is adjusted to-0.35V.

[0026] The open circuit potential of the anode and the cathode is adjusted to-0.35V.

[0027] Compared with the prior art, the present application has at least the following beneficial technical effects:

[0028] 1. The present application uses a small-size two-dimensional nanosheet as an electrode material, significantly reduces the transverse ion transmission distance and increases the number of vertical ion transmission channels, thereby significantly improving the super-high rate charge and discharge capability; by matching the anode and cathode materials, an asymmetric supercapacitor device can be constructed to fully utilize the stable voltage window and realize high voltage and high energy density.

[0029] 2、The application adopts high-conductivity, small-ion-size sulfuric acid electrolyte, uses positive and negative electrode materials with stable electrochemical voltage window, and obtains water-based supercapacitors with a voltage of up to 1.8V, which exhibits similar energy density to organic-based capacitors at low rate.

[0030] The concept, specific structure and generated technical effects of the present application will be further described below in combination with the drawings, so as to fully understand the purposes, features and effects of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 is a method flowchart of a preferred embodiment of the present application;

[0032] Figure 2 is a size statistical diagram of small-size reduced graphene oxide two-dimensional nanosheet of a preferred embodiment of the present application;

[0033] Figure 3 is a size statistical diagram of small-size Ti3C2T x two-dimensional nanosheet of a preferred embodiment of the present application;

[0034] Figure 4 is a scanning electron microscope diagram of a small-size reduced graphene oxide two-dimensional nanosheet hydration film cross section of a preferred embodiment of the present application;

[0035] Figure 5 is a scanning electron microscope diagram of a small-size Ti3C2T x two-dimensional nanosheet hydration film cross section of a preferred embodiment of the present application;

[0036] Figure 6 is a performance diagram of a water-based supercapacitor of a preferred embodiment of the present application;

[0037] Figure 7 is a performance diagram of a water-based supercapacitor of a preferred embodiment of the present application. DETAILED DESCRIPTION

[0038] The following reference description of the drawings introduces a plurality of preferred embodiments of the present application, so that the technical content thereof is more clear and convenient to understand. The present application can be embodied in many different forms of embodiments, and the protection scope of the present application is not limited to the embodiments mentioned herein.

[0039] In the drawings, the same numbers are used to designate the same components throughout the drawings, and components with similar structures or functions are designated by similar numbers. The size and thickness of each component shown in the drawings are arbitrarily shown, and the present application is not limited to the size and thickness of each component. In order to make the drawing clearer, the thickness of the components is appropriately exaggerated in some places in the drawing.

[0040] Example 1

[0041] This embodiment is based on reduced graphene oxide with an average lateral size of approximately 100 nm and Ti3C2T. x Two-dimensional nanosheets, with a surface loading of 5.0 mg / cm² for both positive and negative electrodes. 2 An example of constructing a water-based supercapacitor device. For example... Figure 1 As shown, the specific steps are as follows:

[0042] Step 1: Large-sized graphene oxide two-dimensional nanosheets were obtained by oxidizing flake graphite using Hummer's method. These nanosheets were then hydrothermally reduced using hydrazine hydrate and ammonia to obtain large-sized reduced graphene oxide (LSs-GO) two-dimensional nanosheets. Finally, small-sized reduced graphene oxide (SSs-GO) two-dimensional nanosheets with an average lateral size of approximately 94 nm were obtained through 3 hours of 1800W probe sonication and 8 hours of centrifugation at 11000 rpm. Figure 2 As shown, where, Figure 2 Image a is a scanning electron microscope image of small-sized reduced graphene oxide two-dimensional nanosheets. Figure 2 b. Distribution of the lateral dimensions of two-dimensional nanosheets.

[0043] Step 2: Large-size Ti3C2T fabrication using LiF / HCl etching method x Two-dimensional nanosheets were obtained by 1 hour of 650W probe sonication and 2 hours of centrifugation at 10,000 rpm to obtain small-sized Ti3C2T nanosheets with an average lateral size of approximately 126 nm. x Two-dimensional nanosheets, such as Figure 3 As shown, where, Figure 3 Image a is a scanning electron microscope image of small-sized Ti3C2Tx two-dimensional nanosheets. Figure 3 b represents the distribution of the lateral dimensions of the two-dimensional nanosheets.

[0044] Step 3: Using a 38mm diameter vacuum filtration device, add small-sized graphene oxide two-dimensional nanosheets or small-sized Ti3C2T containing 60mg to the surface of the microporous filter membrane. x A suspension of two-dimensional nanosheets is vacuum filtered until the liquid disappears, then immediately stopped. This process yields small-sized hydrated films of graphene oxide two-dimensional nanosheets and small-sized Ti3C2T nanosheets, respectively. x Two-dimensional nanosheet hydrated thin films, in which nanoparticles are arranged parallel to the surface, such as... Figure 4 , Figure 5 As shown, a small-sized graphene oxide two-dimensional nanosheet hydrated film serves as the positive electrode, and a small-sized Ti3C2T... x Two-dimensional nanosheet hydrated thin films are used as negative electrodes.

[0045] Step 4, the small size graphene oxide two-dimensional nanosheet hydration film and small size Ti3C2T x The two-dimensional nanosheet hydration film is separated by a diaphragm, and an electrolyte is injected to assemble a supercapacitor device. The open circuit potentials of the positive and negative electrodes are adjusted to about -0.35 V. The diaphragm is a layer of glass fiber filter membrane, and the electrolyte is 3 mol / L H2SO4.

[0046] The performance of the supercapacitor is verified, such as Figure 6 as shown in the figure, wherein, Figure 6 a is the cyclic voltammetry curve (scan rate is 10 mV / s) of the positive and negative electrodes, Figure 6 b is the constant current charge-discharge curve of the aqueous supercapacitor device at different voltages (current density is 1 A / g), Figure 6 c is the real-time potential of the positive and negative electrodes during the constant current charge-discharge process, Figure 6 d is the cyclic voltammetry curve of the aqueous supercapacitor device at different voltages (scan rate is 10 mV / s), Figure 6 e is the mass specific energy density and coulombic efficiency of the aqueous supercapacitor device at different voltages. The test results show that the device voltage can reach 1.8 V, and the energy density is 0.29 Wh / cm 2 at a discharge rate of about 14 C, and the energy densities are 0.14 and 0.09 Wh / cm 2 at ultra-high rates of 2000 C and 3700 C, respectively. The capacitance retention rate is greater than 95% after 10000 charge-discharge cycles at a current density of 10 A / g, as shown in Figure 7 as shown in the figure, wherein, Figure 7 a is the cyclic voltammetry curve of the aqueous supercapacitor device at different scan rates, Figure 7 b is the constant current charge-discharge curve of the aqueous supercapacitor device at different current densities, Figure 7 c is the energy density and power density of the aqueous supercapacitor device, Figure 7 d is the cycle stability of the aqueous supercapacitor device.

[0047] Example 2

[0048] This embodiment is a construction example of an aqueous supercapacitor device based on electrochemically exfoliated graphene and Ti3C2T x two-dimensional nanosheets with an average lateral size of about 100 nm, and the surface loadings of the positive and negative electrodes are both 5.0 mg / cm 2 . The specific steps are as follows:

[0049] Step 1, using 0.1M (NH4)2SO4 aqueous solution as electrolyte, graphite paper and platinum mesh as anode and cathode respectively, using direct current power to apply 10V voltage to graphite to obtain large size graphene two-dimensional nanosheet by electrochemical exfoliation, and then purifying by 3h of 1800W probe ultrasonic and 3h of 11000rpm centrifugation to obtain small size electrochemically exfoliated graphene two-dimensional nanosheet with average lateral size of about 100nm.

[0050] Step 2, using LiF / HCl method to etch to prepare large size Ti3C2T x two-dimensional nanosheet, and then purifying by 1h of 650W probe ultrasonic and 2h of 10000rpm centrifugation to obtain small size Ti3C2T x two-dimensional nanosheet with average lateral size of about 100nm.

[0051] Step 3, using 38mm diameter suction filtration device, adding small size electrochemically exfoliated graphene two-dimensional nanosheet or small size Ti3C2T x two-dimensional nanosheet suspension containing 60mg nanosheet on the surface of microporous filter membrane, vacuum suction filtration until the liquid disappears, and then stopping immediately to obtain small size electrochemically exfoliated graphene two-dimensional nanosheet hydration film and small size Ti3C2T 2 two-dimensional nanosheet hydration film with active material surface loading of 5.0mg / cm x respectively.

[0052] Step 4, using a separator to separate the small size electrochemically exfoliated graphene two-dimensional nanosheet hydration film and small size Ti3C2T x two-dimensional nanosheet hydration film, and then injecting electrolyte to assemble supercapacitor device, and adjusting the open circuit potential of the positive and negative electrodes to about-0.35V. The separator is a layer of glass fiber filter membrane, and the electrolyte is 3mol / L H2SO4.

[0053] The performance of the supercapacitor was verified, and the test results showed that the voltage of the device could reach 1.8V, and the energy density could reach 0.28Wh / cm 2 at about 10C discharge rate, and the energy density could reach 0.15Wh / cm 2 at 2000C superhigh rate, and the capacitance retention rate was greater than 95% after 10000 charge and discharge cycles at a current density of 10A / g.

[0054] Example 3

[0055] This example is based on electrochemically exfoliated graphene and Ti3C2T x two-dimensional nanosheet with average lateral size of about 50nm, and the surface loading of the positive and negative electrodes is 5.0mg / cm 2The construction of a water-based supercapacitor device is shown in the following steps.

[0056] Step 1, using 0.1M (NH4)2SO4 aqueous solution as electrolyte, graphite paper and platinum mesh as positive and negative electrodes respectively, using a direct current power supply to apply a voltage of 10V to the graphite to obtain large-size graphene two-dimensional nanosheets by electrochemical exfoliation, and then purifying by 3h of 1800W probe ultrasonic and 8h of 11000rpm centrifugation to obtain small-size electrochemically exfoliated graphene two-dimensional nanosheets with an average lateral size of about 50nm.

[0057] Step 2, using LiF / HCl method to etch to prepare large-size Ti3C2T x two-dimensional nanosheets, and then purifying by 3h of 650W probe ultrasonic and 3h of 10000rpm centrifugation to obtain small-size Ti3C2T x two-dimensional nanosheets with an average lateral size of about 100nm.

[0058] Step 3, using a diameter of 38mm suction filter device, adding a suspension containing 60mg of small-size electrochemically exfoliated graphene two-dimensional nanosheets or small-size Ti3C2T x two-dimensional nanosheets on the surface of a microporous filter membrane, and immediately stopping after vacuum suction filtration until the liquid disappears, to obtain an active material surface loading of 5.0mg / cm 2 of small-size electrochemically exfoliated graphene two-dimensional nanosheet hydration film and small-size Ti3C2T x two-dimensional nanosheet hydration film, respectively as the positive and negative electrodes of the supercapacitor.

[0059] Step 4, separating the small-size electrochemically exfoliated graphene two-dimensional nanosheet hydration film and the small-size Ti3C2T x two-dimensional nanosheet hydration film by a separator, and then injecting electrolyte to assemble a supercapacitor device, and adjusting the open circuit potential of the positive and negative electrodes to about-0.35V. The separator is a layer of glass fiber filter membrane, and the electrolyte is 3mol / L H2SO4.

[0060] The performance of the supercapacitor was verified, and the test results showed that the voltage of the device could reach 1.8V, and exhibited an energy density of 0.29Wh / cm 2 at a discharge rate of about 10C, an energy density of 0.17Wh / cm 2 at a super-high rate of 2000C, and a capacitance retention rate of more than 95% after 10000 charge-discharge cycles at a current density of 10A / g.

[0061] Example 4

[0062] This example is based on electrochemically exfoliated graphene and Ti3C2Tx Two-dimensional nanosheets, both positive and negative electrode surface loadings were 5.0 mg / cm 2 Construction example of aqueous supercapacitor device. The specific steps are as follows:

[0063] Step 1, using 0.1M (NH4)2SO4 aqueous solution as electrolyte, graphite paper and platinum mesh as positive and negative electrodes respectively, using direct current power to apply 10V voltage to graphite for electrochemical exfoliation to obtain large size graphene two-dimensional nanosheets, and then through 1h of 650W probe ultrasonic and 2h of 11000rpm centrifugal purification to obtain small size electrochemically exfoliated graphene two-dimensional nanosheets with an average lateral size of about 200nm.

[0064] Step 2, using HF method to etch to prepare large size Ti3C2T x Two-dimensional nanosheets, and then through 1h of 650W probe ultrasonic and 0.5h of 10000rpm centrifugal purification to obtain small size Ti3C2T x Two-dimensional nanosheets with an average lateral size of about 200nm.

[0065] Step 3, using a diameter of 38mm suction filter device, adding a suspension containing 60mg small size electrochemically exfoliated graphene two-dimensional nanosheets or small size Ti3C2T x Two-dimensional nanosheets on the surface of the microporous filter membrane, vacuum suction filtration until the liquid disappears, and then stop immediately to obtain small size electrochemically exfoliated graphene two-dimensional nanosheet hydration film and small size Ti3C2T 2 Two-dimensional nanosheet hydration film with an active material surface loading of 5.0mg / cm x , respectively as the positive and negative electrodes of the supercapacitor.

[0066] Step 4, the small size electrochemically exfoliated graphene two-dimensional nanosheet hydration film and the small size Ti3C2T x Two-dimensional nanosheet hydration film was separated by a separator, and then electrolyte was injected to assemble a supercapacitor device, and the open circuit potential of the positive and negative electrodes was adjusted to about-0.35V. Among them, the separator is a layer of glass fiber filter membrane, and the electrolyte is 3mol / L H2SO4.

[0067] The performance of the supercapacitor was verified, and the test results showed that the voltage of the device could reach 1.8V, and exhibited an energy density of 0.27Wh / cm 2 at a discharge rate of about 10C, an energy density of 0.10Wh / cm 2 at a super-high rate of 2000C, and a capacitance retention rate of more than 95% after 10000 charge and discharge cycles at a current density of 10A / g.

[0068] It can be seen that the supercapacitor device of the present application is realized by selecting positive and negative electrode materials, matching positive and negative electrode capacity and mass, adjusting open circuit potential of positive and negative electrodes, and realizing by constructing short transverse ion channels in the electrodes, which can meet the demand of explosive energy storage and release scene application, and is also a powerful alternative to the current commercial organic supercapacitor at low rate.

[0069] The preferred embodiments of the present application are described in detail above. It should be understood that those of ordinary skill in the art can make many modifications and changes without creative work based on the concept of the present application. Therefore, any technical solutions obtained by logical analysis, reasoning or limited experiments based on the prior art within the concept of the present application should be within the protection scope determined by the claims.

Claims

1. A method for preparing an ultrahigh rate, high energy density aqueous supercapacitor, characterized in that, The method comprises the following steps: Step 1, preparing small-size graphene two-dimensional nanosheets; the lateral size of the small-size graphene two-dimensional nanosheets is 93.5±47.7 nm; the step 1 further comprises: Step 1.1, preparing large-size graphene two-dimensional nanosheets; Step 1.2, obtaining small-size graphene two-dimensional nanosheets by probe ultrasonic and centrifugal purification; Step 2, preparing small size Ti3C2T x two-dimensional nanosheets; the small size Ti3C2T x a lateral size of the two-dimensional nanosheets is 125.8 ± 77.4 nm; the Step 2 further comprises: Step 2.

1. Fabrication of large size Ti3C2T by LiF / HCl etching x Two-dimensional nanosheets; Step 2.

2. Obtaining small size Ti3C2T by probe sonication and purification by centrifugation x Two-dimensional nanosheets; Step 3, preparation of small-size graphene two-dimensional nanosheet hydration film and small-size Ti3C2T x two-dimensional nanosheet hydration film, the small-size graphene two-dimensional nanosheet hydration film as a positive electrode, the small-size Ti3C2T x two-dimensional nanosheet hydration film as a negative electrode; Step 4, the small size graphene two-dimensional nanosheet hydration film and the small size Ti3C2T x The two-dimensional nanosheet hydration film is separated by a diaphragm, and electrolyte is injected to realize assembly of the aqueous supercapacitor.

2. The preparation method of the ultra-high rate, high energy density aqueous supercapacitor according to claim 1, characterized in that, In the step 1.1, the large-size graphene two-dimensional nanosheets are large-size reduced graphene oxide two-dimensional nanosheets or large-size electrochemically exfoliated graphene two-dimensional nanosheets.

3. The method for preparing an ultra-high rate, high energy density aqueous supercapacitor as described in claim 2, characterized in that, The preparation method of the large-size reduced graphene oxide two-dimensional nanosheets comprises: obtaining large-size graphene oxide two-dimensional nanosheets by using Hummer's method to oxidize flake graphite, and then reducing the large-size graphene oxide two-dimensional nanosheets to obtain the large-size reduced graphene oxide two-dimensional nanosheets.

4. The method for preparing an ultra-high rate, high energy density aqueous supercapacitor as described in claim 2, characterized in that, The preparation method of the large-size electrochemically exfoliated graphene two-dimensional nanosheets comprises: using 0.1 M (NH4)2SO4 aqueous solution as an electrolyte, using graphite paper and platinum mesh as an anode and a cathode respectively, and using a direct current power source to apply a voltage of 10 V to graphite to obtain the large-size electrochemically exfoliated graphene two-dimensional nanosheets.

5. The method for preparing an ultra-high rate, high energy density aqueous supercapacitor as described in claim 1, characterized in that, The step 3 further comprises: using a suction filtration device with a diameter of 38 mm, adding 60 mg of the small-size graphene two-dimensional nanosheets or the small-size Ti3C2T x The suspension of two-dimensional nanosheets is immediately stopped after vacuum suction filtration until the liquid disappears, so as to obtain the small-size graphene two-dimensional nanosheet hydration film, the small-size Ti3C2T x The two-dimensional nanosheet hydration film, wherein the nanosheets in the film are arranged in parallel to the surface.

6. The method for preparing an ultra-high rate, high energy density aqueous supercapacitor as described in claim 1, characterized in that, The diaphragm is a glass fiber filter membrane.

7. The method of claim 1, wherein the aqueous supercapacitor has a high energy density and a high power density. The electrolyte is H2SO4.

8. The method for preparing an ultra-high rate, high energy density aqueous supercapacitor as described in claim 1, characterized in that, The open circuit potential of the anode and the cathode is adjusted to -0.35 V.

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