Carbon-based aqueous zinc ion supercapacitor and preparation method thereof

Abstract

The invention discloses a carbon-based aqueous zinc ion supercapacitor and a preparation method thereof, and belongs to the technical field of zinc ion supercapacitors. The capacitor comprises a positive electrode, a negative electrode, a multi-element electrolyte and a porous diaphragm, the anode is an activated carbon composite material; the negative electrode is a rolled zinc foil; the multi-element electrolyte is a mixed system aqueous solution formed by dissolving zinc trifluoromethanesulfonate, zinc sulfate, zinc chloride, zinc perchlorate and an electrolyte additive in deionized water; and the porous diaphragm is glass fiber. The preparation method comprises the following steps: uniformly mixing the activated carbon composite material, the conductive black and the binder in proportion, adding the organic solvent, grinding into slurry, coating the slurry on the carbon paper, performing vacuum drying to obtain the positive electrode plate, and assembling the positive electrode plate with the multi-element electrolyte, the negative electrode and the porous diaphragm. The raw material cost and the energy consumption are low, the operability is greatly improved, and the repeatability is good.

Description

Technical Field

[0001] The present invention belongs to the technical field of zinc ion supercapacitors, and in particular relates to a carbon-based aqueous zinc ion supercapacitor and a preparation method thereof. Background Art

[0002] Due to the irregular and discontinuous nature of renewable energy sources such as solar and wind energy, recyclable electrochemical energy storage systems are needed to meet social needs. Therefore, how to develop efficient, flexible, and environmentally friendly energy storage systems has become a hot topic at the forefront of the energy field. In recent years, zinc-ion supercapacitors have become an emerging and highly sought-after green energy storage device due to their high safety, high capacity, high rate performance, and low cost. This energy storage device can not only effectively alleviate the concerns of traditional supercapacitors in terms of resource scarcity and environmental impact, but also use widely available zinc as an active material, further improving sustainability and economy. Zinc-ion supercapacitors show great potential, but still face several challenges in practical application.

[0003] At present, most aqueous zinc ion supercapacitors use metal foil as electrodes and use traditional aqueous zinc ion supercapacitor electrolytes. These electrolytes are prone to hydrogen evolution reaction, which causes instability during the charge and discharge process. In addition, the corrosion and passivation problems of the electrolyte, as well as the zinc dendrite phenomenon formed by uneven deposition of zinc during the charging process, all limit the long-term stable operation of zinc ion supercapacitors. In the prior art, aqueous zinc ion supercapacitors mostly rely on zinc trifluoromethanesulfonate (Zn(CF3SO3)2) and zinc sulfate (ZnSO4) as electrolyte components. During the charge and discharge cycle, byproducts will be generated and accumulated on the electrode surface, reducing the effective contact area between the positive electrode and the electrolyte, and destroying the stability of the positive electrode microstructure, ultimately leading to a significant attenuation of the supercapacitor capacity.

[0004] In order to solve the above problems, researchers proposed a "salt-in-water" strategy, which limits the activity of free water by increasing the concentration of salt in the electrolyte, thereby inhibiting hydrogen evolution and corrosion passivation at the negative electrode. However, although this method can improve the stability of the negative electrode to a certain extent, it will also lead to a decrease in electrolyte conductivity, an increase in viscosity, and an increase in cost. In addition, although the introduction of organic solvents can partially overcome the above shortcomings, it also brings about the problem of reduced conductivity and may cause new safety risks. Therefore, there is an urgent need to develop an economical and safe aqueous zinc ion supercapacitor to improve its charge and discharge capacity performance and cycle stability. Summary of the Invention

[0005] In response to the above technical problems, the main purpose of the present invention is to provide a carbon-based aqueous zinc ion supercapacitor with stable performance and long cycle life.

[0006] Another object of the present invention is to provide a method for preparing a carbon-based aqueous zinc ion supercapacitor, which has a simple preparation process, low raw material cost and low production energy consumption.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] In a first aspect of the present invention, a carbon-based aqueous zinc ion supercapacitor is provided, comprising a positive electrode, a negative electrode, a multi-electrolyte solution, and a porous diaphragm; wherein:

[0009] The positive electrode is an activated carbon composite material;

[0010] The negative electrode is a zinc foil subjected to roller pressing;

[0011] The multi-electrolyte is a mixed system aqueous solution formed by dissolving zinc trifluoromethanesulfonate, zinc sulfate, zinc chloride, zinc perchlorate and electrolyte additives in deionized water;

[0012] The porous separator is glass fiber.

[0013] Preferably, the method for preparing the activated carbon composite material comprises the following steps:

[0014] (1) adding graphite oxide to deionized water and ultrasonically treating the water to form a uniform graphite oxide dispersion as suspension I;

[0015] (2) adding carbon nanotubes to deionized water, adding a surfactant to assist dispersion, and ultrasonically treating to form a stable carbon nanotube dispersion as suspension II;

[0016] (3) Suspension I and suspension II are mixed together in proportion, and ultrasonically treated until fully dispersed to form a uniform mixed dispersion, which is referred to as suspension III;

[0017] (5) Adding activated carbon and carbon quantum dots to the suspension III, ultrasonically treating the activated carbon and carbon quantum dots to uniformly disperse the activated carbon and carbon quantum dots in the suspension III, washing, filtering, and drying to obtain an activated carbon composite material.

[0018] More preferably, in step (2), the surfactant is selected from one or more of polyvinyl pyrrolidone, polyethylene glycol, sodium lauryl sulfate, sodium dodecylbenzenesulfonate, hexadecyltrimethylammonium bromide, and lecithin.

[0019] Preferably, the negative electrode is a zinc foil subjected to roller pressing, and the pressure of the roller pressing is 10-60t.

[0020] Preferably, the total concentration of the multi-electrolyte is 1-10 mol·L -1The invention discloses a preparation method comprising the following steps: dissolving zinc trifluoromethanesulfonate, zinc sulfate, zinc chloride, and zinc perchlorate in deionized water in proportion, dissolving the solution by ultrasonication to form a uniform solution, adding an electrolyte additive thereto, and dissolving the solution by ultrasonication; wherein the mass ratio of zinc trifluoromethanesulfonate, zinc sulfate, zinc chloride, and zinc perchlorate is 2:0.1-2:0.1-2:0.1-2;

[0021] The amount of the electrolyte additive added is 0.01-0.1 mol·L -1 , selected from one or more of conductive salt additives, film-forming additives and polyol additives.

[0022] More preferably, the mass ratio of zinc trifluoromethanesulfonate, zinc sulfate, zinc chloride and zinc perchlorate in the multi-electrolyte is 2:0.1-1:0.1-1:0.1-1.

[0023] More preferably, the conductive salt additive is selected from one or more of tetramethylammonium chloride, tetraethylammonium bromide, dodecyltrimethylammonium chloride, hexadecyltrimethylammonium bromide, and tetrabutylammonium bromide.

[0024] More preferably, the film-forming additive is selected from one or more of dimethyldithiocarbamate, fluoroethylene carbonate, triethyl phosphate, and benzotriazole.

[0025] More preferably, the polyol additive is selected from one or more of ethylene glycol, propylene glycol, polyethylene glycol, glycerol, diethylene glycol, and pentaerythritol.

[0026] In a second aspect of the present invention, a method for preparing the carbon-based aqueous zinc ion supercapacitor is provided, comprising: uniformly mixing the activated carbon composite material, conductive black (Super P) and binder (PVDF) in proportion, adding an organic solvent to grind into a slurry and coating it on carbon paper, vacuum drying to obtain a positive electrode sheet, and assembling it with the multi-electrolyte, negative electrode and porous diaphragm.

[0027] Preferably, the mass ratio of the activated carbon composite material, conductive black and binder is 7:2:1;

[0028] and / or the organic solvent is N-methylpyrrolidone (NMP);

[0029] The vacuum drying temperature is 60° C., the vacuum drying time is 12 h, and the thickness of the positive electrode sheet is 50-100 μm.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] 1. The multi-electrolyte of the present invention adopts zinc trifluoromethanesulfonate, zinc sulfate, zinc chloride and zinc perchlorate, wherein the mixed system of trifluoromethanesulfonate, sulfate, chloride and perchlorate ions easily forms a stable solid electrolyte interface (SEI). This protective film can effectively prevent side reactions from occurring on the surface of the zinc anode. The introduction of electrolyte additives reconstructs the solvation structure of zinc ions, effectively guides the uniform deposition / stripping of the zinc negative electrode surface, overcomes the problems of zinc negative electrode dendrites and passivation in aqueous zinc ion supercapacitors, improves performance and effectively reduces the cost of zinc ion supercapacitor electrolytes.

[0032] 2. The carbon-based aqueous zinc ion supercapacitor of the present invention has low raw material cost, simple preparation process, low energy consumption, greatly increased operability, good repeatability, stable performance, long cycle life, and excellent electrochemical performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a cyclic voltammogram of the carbon-based aqueous zinc ion supercapacitor in Example 1, where 1st-5th is the cyclic voltammogram from the first to the fifth cycle.

[0034] Figure 2 The carbon-based aqueous zinc ion supercapacitors in Example 1, Example 2 and Comparative Example 3 were tested at 0.2 A·g -1 Cycling performance curves at current density.

[0035] Figure 3 The carbon-based aqueous zinc ion supercapacitors in Comparative Examples 1, 2 and 3 were tested at 0.2 A·g -1 Cycling performance curves at current density.

[0036] Figure 4 The carbon-based aqueous zinc ion supercapacitor in Example 3 and Comparative Example 3 is 0.5mV S -1 Linear sweep voltammogram at scan rate.

[0037] Figure 5 The electrochemical impedance spectroscopy diagrams of the carbon-based aqueous zinc ion supercapacitors in Example 3 and Comparative Examples 1 and 2 are shown.

[0038] Figure 6 This is the surface electron microscope image of the negative electrode zinc foil in Example 1 after 500 cycles.

[0039] Figure 7 This is the surface electron microscope image of the negative electrode zinc foil in Comparative Example 1 after 500 cycles. DETAILED DESCRIPTION

[0040] In order to more fully understand and demonstrate the technical solutions, objectives, and advantages of the present invention, the following is a further detailed and complete description of the technical effects produced by the present invention in conjunction with the accompanying drawings and specific embodiments. Obviously, the described embodiments are only some of the embodiments of the present invention, and not all of them. It should be pointed out that for those skilled in the art, other embodiments obtained without departing from the concept of the present invention are all within the scope of protection of the present invention.

[0041] Example 1

[0042] This embodiment proposes a carbon-based aqueous zinc ion supercapacitor, using an activated carbon composite as the positive electrode material, a roll-pressed zinc foil as the negative electrode, a mixed aqueous solution of zinc trifluoromethanesulfonate, zinc sulfate, zinc chloride, zinc perchlorate, and an electrolyte additive dissolved in deionized water as the multi-electrolyte, and glass fiber as the porous separator. The electrolyte additive is polyethylene glycol 200, and the concentrations of zinc trifluoromethanesulfonate, zinc sulfate, zinc chloride, and zinc perchlorate are 2 mol·L -1 , 0.5 mol·L -1 , 0.5 mol·L -1 and 0.5 mol·L -1 , the volume ratio of polyethylene glycol 200 to the solvent is 20%.

[0043] The preparation method of the multi-electrolyte comprises the following steps: weighing 7.2708 g of zinc trifluoromethanesulfonate, 0.80725 g of zinc sulfate, 0.6814 g of zinc chloride, and 1.3214 g of zinc perchlorate, dissolving them in 5 mL of deionized water, mixing and sonicating to obtain a homogeneous solution; measuring 2 mL of polyethylene glycol 200 and adding it to the homogeneous solution, sonicating for 5 minutes, adding deionized water to make the volume 10 mL, and continuing sonication for 30 minutes to obtain the electrolyte.

[0044] The preparation method of the activated carbon composite material comprises the following steps: adding 0.1 g of graphite oxide to deionized water, performing ultrasonic treatment to form a uniform graphite oxide dispersion (suspension I); adding 0.1 g of carbon nanotubes to deionized water, adding a small amount of surfactant to assist dispersion, and performing ultrasonic treatment to form a stable carbon nanotube dispersion (suspension II); mixing the suspension I and the suspension II in proportion, and performing ultrasonic treatment again until fully dispersed to form a uniform mixed dispersion (suspension III); adding 2 g of activated carbon powder and 0.1 g of carbon quantum dot powder to the mixed dispersion, continuing ultrasonic treatment to uniformly disperse the activated carbon and the carbon quantum dots in the solution, washing, filtering, and drying to obtain the composite material.

[0045] The prepared activated carbon composite material, conductive black and binder PVDF were mixed evenly in a mass ratio of 7:2:1, then NMP was added and ground into a slurry, which was coated on carbon paper with a thickness of 75 μm and baked in a vacuum oven at 60°C for 12 hours to obtain the target electrode sheet.

[0046] The carbon-based aqueous zinc ion supercapacitor of this embodiment is assembled from a multi-electrolyte, a positive electrode, a zinc sheet processed by 20t pressure rolling as a negative electrode, and glass fiber as a separator.

[0047] The electrochemical performance of the zinc ion supercapacitor of this embodiment was tested using an electrochemical workstation and a LAND test system. The voltage range of the cyclic voltammetry test was 0.2-1.8 V, and the scan rate was set to 1 mV·s. -1 , the voltage range of the cyclic charge and discharge test is 0.2-1.8V.

[0048] Example 2

[0049] This embodiment proposes a carbon-based aqueous zinc ion supercapacitor using an activated carbon composite as the positive electrode material, a roll-pressed zinc foil as the negative electrode, a mixed aqueous solution of zinc trifluoromethanesulfonate, zinc sulfate, zinc chloride, zinc acetate, and an electrolyte additive dissolved in deionized water as the multi-electrolyte, and glass fiber as the porous separator. The electrolyte additive is a mixture of polyethylene glycol 200 and tetraethylammonium bromide, and the concentrations of zinc trifluoromethanesulfonate, zinc sulfate, zinc chloride, and zinc perchlorate are 2 mol·L, respectively. -1 , 0.5 mol·L -1 , 0.5 mol·L -1 and 0.5 mol·L -1 The volume ratio of polyethylene glycol 200 to the solvent is 20%, and the concentration of tetraethylammonium bromide is 0.01 mol·L -1 .

[0050] The preparation method of the multi-electrolyte is as follows: 7.2708 g of zinc trifluoromethanesulfonate, 0.80725 g of zinc sulfate, 0.6814 g of zinc chloride, 1.3214 g of zinc perchlorate and 0.021 g of tetraethylammonium bromide are weighed and dissolved in 5 mL of deionized water, mixed and ultrasonically dissolved to obtain a uniform solution; 2 mL of polyethylene glycol 200 is measured and mixed with the above uniform solution, ultrasonicated for 5 minutes, and then deionized water is added to make the volume 10 mL, and ultrasonic treatment is continued for 30 minutes to obtain the electrolyte.

[0051] The preparation method of the activated carbon composite material comprises the following steps: adding 0.1 g of graphite oxide to deionized water, and ultrasonically treating the mixture to form a uniform graphite oxide dispersion (suspension I); adding 0.1 g of carbon nanotubes to deionized water, adding a small amount of surfactant to assist in dispersion, and ultrasonically treating the mixture to form a stable carbon nanotube dispersion (suspension II); mixing the suspension I and the suspension II in proportion, and ultrasonically treating the mixture again to fully disperse the mixture to form a uniform mixed dispersion (suspension III); adding 2 g of activated carbon powder and 0.1 g of carbon quantum dot powder to the mixed dispersion, and continuing ultrasonically treating the mixture to uniformly disperse the activated carbon and the carbon quantum dots in the solution, and washing, filtering, and drying the mixture to obtain the activated carbon composite material.

[0052] The prepared activated carbon composite material, conductive black and binder PVDF were evenly mixed in a mass ratio of 7:2:1, then NMP was added and ground into a slurry, which was coated on carbon paper with a thickness of 75 μm and placed in a vacuum oven at 60°C for 12 hours to obtain the target electrode sheet.

[0053] The carbon-based aqueous zinc ion supercapacitor of this embodiment is assembled from the above-mentioned electrolyte, the positive electrode, a zinc sheet processed by 50t pressure roller pressing as the negative electrode, and glass fiber as the separator.

[0054] The electrochemical performance of the zinc ion supercapacitor of this embodiment was tested using a LAND test system, with the charge and discharge voltage range being 0.2-1.8V.

[0055] The cyclic voltammetry curve of the carbon-based aqueous zinc ion supercapacitor prepared in Example 1 is as follows: Figure 1 As shown, it can be seen that the five-cycle cyclic voltammetry curves are highly overlapped, showing the high reversibility of zinc ion insertion and extraction.

[0056] The carbon-based aqueous zinc ion supercapacitor prepared in Example 1 has a capacitance of 0.2A·g -1 The specific capacity cycling curve at the current density is as follows Figure 2 As shown, it still maintains 95mAh·g after more than 5500 cycles. -1 The specific capacity of the battery is 2.57W, and the capacity retention rate is about 96%. However, after about 500 cycles, the comparative example 3 using only zinc chloride could no longer be tested due to the generation of a series of side reactions and zinc dendrites piercing the diaphragm, resulting in a short circuit.

[0057] The carbon-based aqueous zinc ion supercapacitor prepared in Example 2 has a capacitance of 0.2A·g -1 The cycle performance curve at the current density is as follows Figure 2 As shown, it can still maintain 99mAh·g after 5500 cycles. -1 The specific capacity and capacity retention rate are about 98%.

[0058] like Figure 2As shown, Examples 1 and 2 using the multi-electrolyte have an ultra-long cycle life of more than 5,500 times, while Comparative Example 3 using only zinc chloride has a cycle life of only 500 times, demonstrating the excellent high performance of the multi-electrolyte and its ability to inhibit zinc dendrite growth. Figure 6 It can be seen from the electron microscope image that the zinc foil surface of the zinc ion supercapacitor prepared in Example 1 is still relatively smooth after 500 cycles, and Figure 7 Comparative Example 1 shows large irregular peeling of the zinc foil surface.

[0059] Example 3

[0060] The difference between this embodiment and embodiment 2 is that the concentration of tetraethylammonium bromide is 0.05 mol·L -1 .

[0061] The electrochemical window of the electrolyte solution of this example was tested using an electrochemical workstation linear sweep voltammetry (LSV) test system. The test system was a three-electrode system, with platinum electrodes as the working and counter electrodes and a saturated calomel electrode as the reference electrode. Test parameters were set as follows: starting voltage: -2 V; ending voltage: 2 V; scan rate: 0.5 mV s -1 ; The test environment is 25℃, and the test curve is as follows Figure 4 shown.

[0062] The electrochemical window of the multi-electrolyte in Example 3 successfully increased the electrochemical stability window of the aqueous electrolyte to 2.75 V. At the same time, the AC impedance spectroscopy test was performed on the carbon-based aqueous zinc ion supercapacitor prepared in Example 3. Test parameter settings: frequency: 1 to 10 5 Hz; Amplitude: 5mV; Test environment: 25℃, test curve as follows Figure 5 shown.

[0063] Comparative Example 1

[0064] The difference between this comparative example and Example 1 is that the electrolyte is 2 mol·L -1 Zinc trifluoromethanesulfonate, no electrolyte additives are added.

[0065] The electrochemical performance of the carbon-based aqueous zinc ion supercapacitor of this comparative example was tested using a LAND test system, with a charge and discharge voltage range of 0.2-1.8V.

[0066] At 0.2A·g -1 The specific capacity cycling curve at the current density is as follows Figure 3 As shown in the figure, after 500 cycles, the test could not be continued due to the generation of a series of side reactions and the generation of zinc dendrites that pierced the diaphragm and caused a short circuit. At the same time, the AC impedance spectroscopy test of the carbon-based aqueous zinc ion supercapacitor was performed, and the test parameters were set as follows: frequency: 1~105 Hz; Amplitude: 5mV; Test environment: 25℃, test curve as follows Figure 5 shown.

[0067] Comparative Example 2

[0068] The difference between this comparative example and Example 1 is that the electrolyte is 2 mol·L -1 of zinc sulfate, without adding electrolyte additives.

[0069] The electrochemical performance of the carbon-based aqueous zinc ion supercapacitor of this comparative example was tested using a LAND test system, with a charge and discharge voltage range of 0.2-1.8V.

[0070] At 0.2A·g -1 The specific capacity cycling curve at the current density is as follows Figure 3 As shown in the figure, after 500 cycles, the test could not be continued due to the generation of a series of side reactions and the generation of zinc dendrites that pierced the diaphragm and caused a short circuit. At the same time, the AC impedance spectroscopy test of the carbon-based aqueous zinc ion supercapacitor was performed, and the test parameters were set as follows: frequency: 1~10 5 Hz; Amplitude: 5mV; Test environment: 25℃, test curve as follows Figure 5 shown.

[0071] Comparative Example 3

[0072] The difference between this comparative example and Example 1 is that the electrolyte is 2 mol·L -1 of zinc chloride, without adding electrolyte additives.

[0073] The electrochemical performance of the carbon-based aqueous zinc ion supercapacitor of this embodiment was tested using a LAND test system, with a charge and discharge voltage range of 0.2-1.8V.

[0074] At 0.2A·g -1 The specific capacity cycling curve at the current density is as follows Figure 3 As shown, after 500 cycles, the test could no longer be continued due to the generation of a series of side reactions and the generation of zinc dendrites that pierced the diaphragm and caused a short circuit. At the same time, the electrochemical window of the comparative electrolyte was tested using an electrochemical workstation linear sweep voltammetry test system. The test system was a three-electrode system, with platinum electrodes as the working and counter electrodes and a saturated calomel electrode as the reference electrode. The test parameters were set as follows: starting voltage: -2 V; ending voltage: 2 V; scan rate: 0.5 mV S -1 ; The test environment is 25℃, and the test curve is as follows Figure 4 shown.

[0075] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A carbon-based aqueous zinc ion supercapacitor, characterized in that: It includes a positive electrode, a negative electrode, a multi-electrolyte and a porous separator; wherein: The positive electrode is an activated carbon composite material; The negative electrode is a zinc foil subjected to roller pressing; The multi-electrolyte is a mixed system aqueous solution formed by dissolving zinc trifluoromethanesulfonate, zinc sulfate, zinc chloride, zinc perchlorate and electrolyte additives in deionized water; The porous separator is glass fiber.

2. The carbon-based aqueous zinc ion supercapacitor according to claim 1, characterized in that: The preparation method of the activated carbon composite material comprises the following steps: (1) adding graphite oxide to deionized water and ultrasonically treating the water to form a uniform graphite oxide dispersion as suspension I; (2) adding carbon nanotubes to deionized water, adding a surfactant to assist dispersion, and ultrasonically treating to form a stable carbon nanotube dispersion as suspension II; (3) Suspension I and suspension II are mixed together in proportion, and ultrasonically treated until fully dispersed to form a uniform mixed dispersion, which is referred to as suspension III; (5) Adding activated carbon and carbon quantum dots to the suspension III, ultrasonically treating the activated carbon and carbon quantum dots to uniformly disperse the activated carbon and carbon quantum dots in the suspension III, washing, filtering, and drying to obtain an activated carbon composite material.

3. The carbon-based aqueous zinc ion supercapacitor according to claim 2, characterized in that: In step (2), the surfactant is selected from one or more of polyvinyl pyrrolidone, polyethylene glycol, sodium lauryl sulfate, sodium dodecylbenzenesulfonate, hexadecyltrimethylammonium bromide, and lecithin.

4. The carbon-based aqueous zinc ion supercapacitor according to claim 1, characterized in that The negative electrode is a zinc foil subjected to roller pressing, and the pressure of the roller pressing is 10-60t.

5. The carbon-based aqueous zinc ion supercapacitor according to claim 1, characterized in that: The total concentration of the multi-electrolyte is 1-10 mol·L -1 The preparation method comprises: dissolving zinc trifluoromethanesulfonate, zinc sulfate, zinc chloride and zinc perchlorate in deionized water in a mass ratio of 2:0.1-2:0.1-2:0.1-2 in sequence, ultrasonically dissolving to form a uniform solution, adding an electrolyte additive thereto, and ultrasonically dissolving to obtain the electrolyte; The amount of electrolyte additive added is 0.01-0.1 mol·L -1 , selected from one or more of conductive salt additives, film-forming additives and polyol additives.

6. The carbon-based aqueous zinc ion supercapacitor according to claim 5, characterized in that: The mass ratio of zinc trifluoromethanesulfonate, zinc sulfate, zinc chloride and zinc perchlorate in the multi-electrolyte is 2:0.1-1:0.1-1:0.1-1.

7. The carbon-based aqueous zinc ion supercapacitor according to claim 5, characterized in that: The conductive salt additive is selected from one or more of tetramethylammonium chloride, tetraethylammonium bromide, dodecyltrimethylammonium chloride, hexadecyltrimethylammonium bromide, and tetrabutylammonium bromide; and / or the film-forming additive is selected from one or more of dimethyldithiocarbamate, fluoroethylene carbonate, triethyl phosphate, and benzotriazole; And / or the polyol additive is selected from one or more of ethylene glycol, propylene glycol, polyethylene glycol, glycerol, diethylene glycol, and pentaerythritol.

8. The method for preparing a carbon-based aqueous zinc ion supercapacitor according to any one of claims 1 to 7, characterized in that: include: The activated carbon composite material, conductive black and binder are mixed evenly in proportion, added with an organic solvent, ground into a slurry and coated on carbon paper, and vacuum dried to obtain a positive electrode sheet, which is assembled with the multi-electrolyte, negative electrode and porous diaphragm.

9. The method for preparing a carbon-based aqueous zinc ion supercapacitor according to claim 8, characterized in that: The mass ratio of the activated carbon composite material, conductive black and binder is 7:2:1, the thickness of the positive electrode sheet is 50-100 μm; and / or the organic solvent is N-methylpyrrolidone.

10. The method for preparing a carbon-based aqueous zinc ion supercapacitor according to claim 8, characterized in that: The vacuum drying temperature is 60°C and the vacuum drying time is 12 h.

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