CN111725002A

CN111725002A - Water system alkaline electrolyte and application thereof, zinc-based hybrid supercapacitor and preparation method thereof

Info

Publication number: CN111725002A
Application number: CN201910207453.4A
Authority: CN
Inventors: 刘宇; 贺亮; 袁新海; 付丽君; 吴宇平
Original assignee: Nanjing Tech University
Current assignee: Nanjing Tech University
Priority date: 2019-03-19
Filing date: 2019-03-19
Publication date: 2020-09-29

Abstract

The invention discloses an application of a water system alkaline electrolyte in preparing an electrolyte of a zinc-based hybrid supercapacitor, wherein the water system alkaline electrolyte comprises alkali and water, the alkali is alkali metal hydroxide and/or alkali metal acetate, and the concentration of the alkali is 0.1-13 mol/L. The invention also discloses a water system alkaline electrolyte, which comprises alkali, zinc salt and water, wherein the alkali is alkali metal hydroxide and/or alkali metal acetate, the concentration of the alkali is 0.1-13mol/L, and the molar concentration ratio of the alkali to the zinc salt is more than 100:1 and less than or equal to 13000: 1. The invention further provides a zinc-based hybrid supercapacitor and a preparation method thereof. The zinc-based hybrid supercapacitor prepared by the invention can maintain or obtain a wider electrochemical window on the basis of maintaining the power density, has higher specific capacity and energy density, and shows high capacitance retention rate in a long-cycle effect test.

Description

Water system alkaline electrolyte and application thereof, zinc-based hybrid supercapacitor and preparation method thereof

Technical Field

The invention relates to the technical field of capacitors, in particular to a water system alkaline electrolyte and application thereof, a zinc-based hybrid supercapacitor and a preparation method thereof.

Background

Currently, more than 80% of the global energy consumption comes from traditional non-renewable energy sources, such as: coal, oil, natural gas, etc. The consumption of non-renewable energy sources brings social problems of energy shortage, environmental pollution and the like, but the use of clean renewable energy sources such as solar energy, wind energy and the like and the research and development of energy storage devices are promoted. Among many energy storage devices, lithium ion batteries and super capacitors are widely used in portable electronic devices such as mobile phones, digital cameras, and notebook computers, and research on them is increasing. The conventional lithium ion battery uses graphite material as a negative electrode and transition metal oxide (LiMn)₂O₄、LiCoO₂、LiNi_xMn_yCo_1-x-yO₂) Or polyanionic metal compounds (LiFePO)₄) As the positive electrode, an organic solution containing a lithium salt is used as an electrolyte. However, the relatively active chemical property and limited storage capacity of lithium result in a high price of the existing lithium ion battery, and the existing lithium ion battery has certain potential safety hazard in the use process. In addition, the power density of the traditional lithium ion battery is low, and the cycle life is short. Therefore, the development of energy storage devices based on other ions is of great interest.

The super capacitor is a novel energy storage device between a traditional capacitor and a battery, and is divided into an electric double layer capacitor and a pseudo capacitor from a mechanism perspective, wherein the electric double layer capacitor stores electric energy through an electric double layer formed on the surface of an electrode by electrolyte ions; pseudocapacitors store electrical energy by a rapid reversible redox reaction at the electrode surface. The super capacitor has the advantages of high specific power, long cycle life, large-current charging and discharging, environmental friendliness, safety, no maintenance and the like. The hybrid super capacitor has the common advantages of a battery and a super capacitor, has the characteristics of high energy density, long cycle life and high power density, and has wide application prospects in the fields of electronic information, instruments and meters, aerospace and transportation.

In the chinese invention patent application with publication number CN107369567A, shenzhen zhong koraineng limited, shenzhen technical research institute has proposed a zinc-based hybrid supercapacitor based on this, the negative electrode active material is a carbon material capable of performing ion reversible adsorption, the negative electrode is any one of zinc, zinc alloy or a composite material of zinc and nonmetal, and the electrolyte is composed of zinc salt and an organic solvent. The non-aqueous neutral electrolyte used by the zinc-based hybrid capacitor has higher cost, low safety performance, and lower energy density and power density. Further, in chinese invention patent applications publication nos. CN103560019A and CN103545123A, the first automotive gmbh of china proposed a zinc ion-based hybrid supercapacitor. In patent application publication No. CN103560019A, the negative electrode active material is a carbon material capable of reversible adsorption of ions, the positive electrode active material is a composite metal oxide, and the electrolyte is composed of zinc salt and deionized water; in patent application publication No. CN103545123A, the negative electrode active material is a composite of zinc and a carbon material capable of ion reversible adsorption, the positive electrode active material is a composite of a composite metal oxide and a carbon material capable of ion reversible adsorption, and the electrolyte is also composed of a zinc salt and deionized water. The zinc-based hybrid super capacitor in the two patent applications uses a water system neutral electrolyte, and the positive electrode material is a composite metal oxide, so that the zinc-based hybrid super capacitor prepared from the electrolyte has a narrow electrochemical window and lower conductivity, power density and energy density.

In 2018, Feiyu Kang et al reported a new type of zinc-based hybrid supercapacitor (EnergyStorage Materials,2018,13,96-102), in which the electrolyte used was an aqueous neutral electrolyte, and zinc salt was zinc sulfate. The electrochemical performance test shows that when the current density is 5A g^-1When the specific capacity is 60mAh/g, the electrochemical window is 0.2-1.8V, and the energy density is 48Wh kg^-1. However, zinc using the electrolyteThe electrochemical window of the base hybrid super capacitor is narrow, and the specific capacity and the energy density are lower.

In 2016, a class of Zn// Co reported by the task group of Palim₃O₄A battery (adv. Mater.2016,28, 4904-. The electrolyte contains 1M KOH and 10mM Zn (Ac)₂And also contains polymer polyvinyl alcohol. However, the working principles of batteries and supercapacitors are significantly different, and the role of the electrolyte therein is also significantly different. In the battery, the electrolyte plays a role of conducting ions between the positive electrode and the negative electrode, and the ions enter the positive electrode material phase and the negative electrode material phase to participate in electrochemical reaction. The super capacitor generally adopts an electric double layer to store energy, when in charging, electrons are transmitted from an anode to a cathode through an external power supply, so that the anode and the cathode are respectively charged with positive electricity and negative electricity, and simultaneously positive ions and negative ions in electrolyte are separated and move to the surface of the electrode to be opposite to a charge layer on the surface of the electrode to form the electric double layer; during discharge, electrons flow from the negative electrode to the positive electrode through the load, and positive and negative ions are released from the electrode surface and return to the electrolyte, while the electric double layer disappears. At present, there is no report that an aqueous alkaline electrolyte in the battery field is applied to a zinc-based capacitor.

Disclosure of Invention

The invention aims to overcome the defects of narrow electrochemical window, low specific capacitance and energy density and the like of the conventional zinc-based hybrid capacitor, and provides a water system alkaline electrolyte, application thereof, a zinc-based hybrid supercapacitor and a preparation method thereof. The water system alkaline electrolyte is used for preparing the electrolyte of the zinc-based hybrid supercapacitor for the first time, and the prepared zinc-based hybrid supercapacitor can maintain or obtain a wider electrochemical window on the basis of maintaining power density, has higher specific capacity and energy density, and shows high capacity retention rate in a long-cycle effect test.

The invention solves the technical problems through the following technical scheme.

The invention provides an application of an aqueous alkaline electrolyte in preparing an electrolyte of a zinc-based hybrid supercapacitor, wherein the aqueous alkaline electrolyte comprises alkali and water, the alkali is alkali metal hydroxide and/or alkali metal acetate, and the concentration of the alkali is 0.1-13 mol/L.

The invention also provides an aqueous alkaline electrolyte, which comprises alkali, zinc salt and water, wherein the alkali is alkali metal hydroxide and/or alkali metal acetate, the concentration of the alkali is 0.1-13mol/L, and the molar concentration ratio of the alkali to the zinc salt is more than 100:1 and less than or equal to 13000: 1.

In the present invention, the alkali metal hydroxide may be an alkali metal hydroxide that is conventional in the chemical field, preferably one or more of lithium hydroxide, sodium hydroxide, and potassium hydroxide, and more preferably potassium hydroxide.

In the present invention, the alkali metal acetate may be one or more of alkali metal acetates that are conventional in the chemical field, such as lithium acetate, sodium acetate, and potassium acetate.

In the present invention, the concentration of the base may be 0.1mol/L, 1mol/L, 1.5mol/L, 2mol/L, 3mol/L, 4mol/L, 5mol/L, 6mol/L, 7mol/L, 8mol/L, 9mol/L, 10mol/L or 13mol/L, preferably 1 to 10mol/L, more preferably 3 to 7mol/L, further preferably 5 to 7mol/L, for example 6 mol/L.

In the application provided by the invention, the aqueous alkaline electrolyte can also comprise zinc salt. The zinc salt that may be further contained in the aqueous basic electrolyte in the application provided by the present invention and the zinc salt contained in the aqueous basic electrolyte provided by the present invention may be zinc salts conventionally used in the art, preferably one or more of zinc trifluoromethanesulfonate, zinc bis (trifluoromethylsulfonyl) imide, zinc tetrafluoroborate, zinc hexafluorophosphate, zinc hexafluoroarsenate, zinc perchlorate, zinc chlorate, zinc phosphate, zinc nitrate, zinc sulfate, zinc acetate, and zinc chloride, more preferably one or more of zinc sulfate, zinc acetate, zinc nitrate, zinc chloride, zinc bis (trifluoromethylsulfonyl) imide, and zinc perchlorate, and still more preferably zinc sulfate.

The concentration of the zinc salt is 0.001 to 0.5mol/L or more and less than 0.001mol/L and less than 0.13mol/L, for example, 0.001mol/L, 0.003mol/L, 0.005mol/L, 0.008mol/L, 0.01mol/L, 0.015mol/L, 0.02mol/L, 0.05mol/L, 0.06mol/L, 0.1mol/L, 0.13mol/L, 0.2mol/L, 0.3mol/L or 0.5mol/L, preferably 0.01 to 0.5mol/L or more and less than 0.01mol/L and less than 0.13mol/L, more preferably 0.01 to 0.06mol/L, further preferably 0.01 to 0.03mol/L, for example, 0.02 mol/L.

The molar concentration ratio of the base to the zinc salt is 5-13000:1, such as 5:1, 12:1, 30:1, 50:1, 100:1, 120:1, 150:1, 250:1, 300:1, 500:1, 600:1, 650:1 or 6000:1, preferably 100-.

In the present invention, the aqueous alkaline electrolyte may further include a polymer. The polymer may be a polymer capable of absorbing a liquid electrolyte to form a sol or gel state, conducting ions between two electrodes, and not conducting electrons, preferably one or more of polyethylene oxide (PEO), polyvinyl chloride (PVC), Polyacrylonitrile (PAN), polymethyl methacrylate (PMMA), Polytetrafluoroethylene (PTFE), polyvinyl alcohol (PVA), polyacrylic acid (PAA), polyvinyl imidazole, polyhydroxypropylacrylate, polyvinyl imidazole-hydroxypropyl acrylate, polydopamine, and poly sodium alginate, preferably one or more of polyethylene oxide, polyvinyl chloride, polymethyl methacrylate, polyvinyl alcohol, polyvinyl imidazole, polyacrylic acid, polydopamine, and poly sodium alginate, and more preferably polyvinyl alcohol. The mass-to-volume ratio of the polymer to the water is 1:8 to 1:20g/mL, such as 1:8g/mL, 1:10g/mL, 1:12g/mL, 1:15g/mL, 1:18g/mL, or 1:20g/mL, preferably 1:10 to 1:20g/mL, such as 1:10 g/mL.

In the present invention, the water may be water conventional in the art, and preferably deionized water.

In one embodiment of the present invention, the aqueous alkaline electrolyte is a mixed solution of alkali and water, the concentration of the alkali is 0.1 to 13mol/L, and the alkali is one or more of lithium hydroxide, sodium hydroxide and potassium hydroxide.

In one embodiment of the present invention, the aqueous alkaline electrolyte is a mixed solution of alkali and water, the concentration of the alkali is 3 to 7mol/L, and the alkali is one or more of lithium hydroxide, sodium hydroxide and potassium hydroxide.

In one embodiment of the present invention, the aqueous alkaline electrolyte is a mixed solution of an alkali and water, the concentration of the alkali is 5 to 7mol/L, and the alkali is one or more of lithium hydroxide, sodium hydroxide and potassium hydroxide.

In one embodiment of the present invention, the aqueous alkaline electrolyte is a mixed solution of zinc salt, alkali and water; the zinc salt is one or more of zinc sulfate, zinc acetate, zinc nitrate and zinc chloride, and the alkali is one or more of lithium hydroxide, sodium hydroxide and potassium hydroxide; the concentration of the alkali is 0.1-13mol/L, the concentration of the zinc salt is 0.001-0.5mol/L, and the molar concentration ratio of the alkali to the zinc salt is 5-13000: 1.

In one embodiment of the present invention, the aqueous alkaline electrolyte is a mixed solution of zinc salt, alkali and water; the zinc salt is one or more of zinc sulfate, zinc acetate, zinc nitrate and zinc chloride, and the alkali is one or more of lithium hydroxide, sodium hydroxide and potassium hydroxide; the concentration of the alkali is 0.1-13mol/L, the concentration of the zinc salt is 0.001-0.5mol/L, and the molar concentration ratio of the alkali to the zinc salt is 100-13000: 1.

In one embodiment of the present invention, the aqueous alkaline electrolyte is a mixed solution of zinc salt, alkali and water; the zinc salt is one or more of zinc sulfate, zinc acetate, zinc nitrate and zinc chloride, and the alkali is one or more of lithium hydroxide, sodium hydroxide and potassium hydroxide; the concentration of the alkali is 0.1-13mol/L, the concentration of the zinc salt is more than or equal to 0.001mol/L and less than 0.13mol/L, and the molar concentration ratio of the alkali to the zinc salt is more than 100:1 and less than or equal to 13000: 1.

In one embodiment of the present invention, the aqueous alkaline electrolyte is a mixed solution of zinc salt, alkali and water; the zinc salt is one or more of zinc sulfate, zinc acetate, zinc nitrate and zinc chloride, and the alkali is one or more of lithium hydroxide, sodium hydroxide and potassium hydroxide; the concentration of the alkali is 0.1-13mol/L, the concentration of the zinc salt is 0.001-0.5mol/L, and the molar concentration ratio of the alkali to the zinc salt is more than 100-7000: 1.

In one embodiment of the present invention, the aqueous alkaline electrolyte is a mixed solution of zinc salt, alkali and water; the zinc salt is zinc sulfate, and the alkali is one or more of lithium hydroxide, sodium hydroxide and potassium hydroxide; the concentration of the alkali is 1-10mol/L, the concentration of the zinc salt is 0.01-0.06mol/L, and the molar concentration ratio of the alkali to the zinc salt is more than 100:1 and less than or equal to 7000: 1.

In one embodiment of the present invention, the aqueous alkaline electrolyte is a mixed solution of zinc salt, alkali and water; the zinc salt is zinc sulfate, and the alkali is one or more of lithium hydroxide, sodium hydroxide and potassium hydroxide; the concentration of the alkali is 1-10mol/L, the concentration of the zinc salt is 0.01-0.5mol/L, and the molar concentration ratio of the alkali to the zinc salt is 120-1000: 1. In one embodiment of the present invention, the aqueous alkaline electrolyte is a mixed solution of zinc salt, alkali and water; the zinc salt is zinc sulfate, and the alkali is one or more of lithium hydroxide, sodium hydroxide and potassium hydroxide; the concentration of the alkali is 1-10mol/L or 3-7mol/L, the concentration of the zinc salt is 0.01-0.06mol/L, and the molar concentration ratio of the alkali to the zinc salt is 150-600: 1. In one embodiment of the present invention, the aqueous alkaline electrolyte is a mixed solution of zinc salt, alkali and water; the zinc salt is zinc sulfate, and the alkali is one or more of lithium hydroxide, sodium hydroxide and potassium hydroxide; the concentration of the alkali is 3-7mol/L, the concentration of the zinc salt is 0.01-0.03mol/L, and the molar concentration ratio of the alkali to the zinc salt is 150-600:1 or 150-350: 1.

In one embodiment of the present invention, the aqueous alkaline electrolyte is an electrolyte composed of a zinc salt, an alkali, water and a polymer; the zinc salt is one or more of zinc sulfate, zinc acetate, zinc nitrate and zinc chloride, the alkali is one or more of lithium hydroxide, sodium hydroxide and potassium hydroxide, and the polymer is one or more of polyethylene oxide, polyvinyl chloride, polymethyl methacrylate, polyvinyl alcohol and polyacrylic acid; the concentration of the alkali is 0.1-13mol/L, the concentration of the zinc salt is 0.001-0.5mol/L, the molar concentration ratio of the alkali to the zinc salt is 5-13000:1, and the mass-volume ratio of the polymer to the water is 1:8-1:20 g/mL.

In one embodiment of the present invention, the aqueous alkaline electrolyte is an electrolyte composed of a zinc salt, an alkali, water and a polymer; the zinc salt is one or more of zinc sulfate, zinc acetate, zinc nitrate and zinc chloride, the alkali is one or more of lithium hydroxide, sodium hydroxide and potassium hydroxide, and the polymer is one or more of polyethylene oxide, polyvinyl chloride, polymethyl methacrylate, polyvinyl alcohol and polyacrylic acid; the concentration of the alkali is 0.1-13mol/L, the concentration of the zinc salt is 0.001-0.5mol/L, the molar concentration ratio of the alkali to the zinc salt is more than 100-13000:1, and the mass-volume ratio of the polymer to the water is 1:8-1:20 g/mL.

In one embodiment of the present invention, the aqueous alkaline electrolyte is an electrolyte composed of a zinc salt, an alkali, water and a polymer; the zinc salt is one or more of zinc sulfate, zinc acetate, zinc nitrate and zinc chloride, the alkali is one or more of lithium hydroxide, sodium hydroxide and potassium hydroxide, and the polymer is one or more of polyethylene oxide, polyvinyl chloride, polymethyl methacrylate, polyvinyl alcohol and polyacrylic acid; the concentration of the alkali is 0.1-13mol/L, the molar concentration ratio of the alkali to the zinc salt is more than 100:1 and less than or equal to 13000:1, the concentration of the zinc salt is more than or equal to 0.001mol/L and less than 0.13mol/L, and the mass-volume ratio of the polymer to the water is 1:8-1:20 g/mL.

In one embodiment of the present invention, the aqueous alkaline electrolyte is an electrolyte composed of a zinc salt, an alkali, water and a polymer; the zinc salt is one or more of zinc sulfate, zinc acetate, zinc nitrate and zinc chloride, the alkali is one or more of lithium hydroxide, sodium hydroxide and potassium hydroxide, and the polymer is one or more of polyethylene oxide, polyvinyl chloride, polymethyl methacrylate, polyvinyl alcohol and polyacrylic acid; the concentration of the alkali is 0.1-13mol/L, the concentration of the zinc salt is 0.001-0.5mol/L, the molar concentration ratio of the alkali to the zinc salt is 100-7000:1, and the mass-volume ratio of the polymer to the water is 1:8-1:20 g/mL.

In one embodiment of the present invention, the aqueous alkaline electrolyte is an electrolyte composed of a zinc salt, an alkali, water and a polymer; the zinc salt is zinc sulfate, the alkali is one or more of lithium hydroxide, sodium hydroxide and potassium hydroxide, and the polymer is one or more of polyoxyethylene, polyvinyl chloride, polymethyl methacrylate, polyvinyl alcohol and polyacrylic acid; the concentration of the alkali is 1-10mol/L, the concentration of the zinc salt is 0.01-0.06mol/L, the molar concentration ratio of the alkali to the zinc salt is more than 100:1 and less than or equal to 7000:1, and the mass-volume ratio of the polymer to the water is 1:8-1:20g/mL

In one embodiment of the present invention, the aqueous alkaline electrolyte is an electrolyte composed of a zinc salt, an alkali, water and a polymer; the zinc salt is zinc sulfate, the alkali is one or more of lithium hydroxide, sodium hydroxide and potassium hydroxide, and the polymer is one or more of polyoxyethylene, polyvinyl chloride, polymethyl methacrylate, polyvinyl alcohol and polyacrylic acid; the concentration of the alkali is 1-10mol/L, the concentration of the zinc salt is 0.01-0.5mol/L, the molar concentration ratio of the alkali to the zinc salt is 120-1000:1, and the mass-volume ratio of the polymer to the water is 1:8-1:20 g/mL.

In one embodiment of the present invention, the aqueous alkaline electrolyte is an electrolyte composed of a zinc salt, an alkali, water and a polymer; the zinc salt is zinc sulfate, the alkali is one or more of lithium hydroxide, sodium hydroxide and potassium hydroxide, and the polymer is one or more of polyoxyethylene, polyvinyl chloride, polymethyl methacrylate, polyvinyl alcohol and polyacrylic acid; the concentration of the alkali is 1-10mol/L or 3-7mol/L, the concentration of the zinc salt is 0.01-0.06mol/L, the molar concentration ratio of the alkali to the zinc salt is 150-600:1, and the mass-volume ratio of the polymer to the water is 1:8-1:20 g/mL.

In one embodiment of the present invention, the aqueous alkaline electrolyte is an electrolyte composed of a zinc salt, an alkali, water and a polymer; the zinc salt is zinc sulfate, the alkali is one or more of lithium hydroxide, sodium hydroxide and potassium hydroxide, and the polymer is polyvinyl alcohol; the concentration of the alkali is 3-7mol/L, the concentration of the zinc salt is 0.01-0.03mol/L, the molar concentration ratio of the alkali to the zinc salt is 150-600:1 or 150-350:1, and the mass-volume ratio of the polymer to the water is 1:10-1:20 g/mL.

The invention also provides a zinc-based hybrid supercapacitor which comprises the aqueous alkaline electrolyte.

The invention also provides a preparation method of the zinc-based hybrid supercapacitor, and when the aqueous alkaline electrolyte does not comprise a polymer, the preparation method comprises the following steps: assembling the positive electrode, the diaphragm, the negative electrode and the aqueous alkaline electrolyte;

when the aqueous alkaline electrolyte includes a polymer, the preparation method may be any of the following methods:

the method comprises the following steps: assembling the positive electrode, the diaphragm, the negative electrode and the aqueous alkaline electrolyte;

the second method comprises the following steps: soaking a polymer film made of a polymer in an aqueous alkaline electrolyte without the polymer to obtain a soaked polymer film, and assembling the anode, the cathode and the soaked polymer film.

In one embodiment of the present invention, the preparation method comprises the following steps:

(a) preparing a positive electrode: preparing an electrode film from a positive electrode active material, a conductive agent and a binder, pressing the electrode film on a current collector with a required size, and drying the electrode film to obtain a positive plate;

(b) preparing a negative electrode: processing the cathode material with the required size to be used as a cathode for standby;

(c) preparing a diaphragm: taking a porous polymer film, an inorganic porous film or an organic/inorganic composite film with a required size as a diaphragm;

(d) preparing an aqueous alkaline electrolyte: dissolving alkali or alkali and zinc salt in water; or dissolving the polymer in water, and adding alkali or alkali and zinc salt;

assembling the positive electrode obtained in the step (a), the negative electrode obtained in the step (b), the separator obtained in the step (c), and the electrolyte obtained in the step (d).

(c) preparing an aqueous alkaline electrolyte-impregnated polymer film: dissolving alkali or alkali and zinc salt in water; dissolving a polymer in a solvent to prepare a polymer solution, then using a scraper to scrape and dry the polymer solution to prepare a polymer film, and finally soaking the polymer film in an aqueous solution of alkali or alkali and zinc salt to obtain a soaked polymer film; wherein the solvent comprises one or more of water, tetrahydrofuran, dimethylformamide, cyclohexanone and acetone.

Assembling the positive electrode obtained in the step (a), the wetted polymer film obtained in the step (c), and the negative electrode obtained in the step (b).

In the invention, the positive electrode comprises a positive electrode material and a positive electrode current collector. The positive electrode material comprises a positive electrode active material, a conductive agent and a binder.

In the present invention, the positive electrode active material may be a material capable of reversibly adsorbing/desorbing anions and cations in an electrolyte, or a composite of a material capable of reversibly adsorbing/desorbing anions and cations in an electrolyte and a material capable of reversibly intercalating/deintercalating zinc ions, or anions and cations in an electrolyte. The positive electrode active material is preferably one or more of a carbon material, a modified carbon material, a sulfide, a nitride, an oxide, a hydroxide, a selenide, a carbide, a transition metal cyanide, a oxyhydroxide, a conductive polymer, and a metal organic framework Material (MOF).

In the present invention, the carbon material may be a carbon material conventionally used in the art, such as mesocarbon microbeads, natural graphite, expanded graphite, artificial graphite, glassy carbon, carbon-carbon composites, carbon fibers (e.g., carbon nanofibers), hard carbon, soft carbon, activated carbon, porous carbon, carbon cloth, carbon paper, three-dimensional graphite, carbon black, carbon nanotubes (e.g., single-walled carbon nanotubes, multi-walled carbon nanotubes), graphene (e.g., graphene sheets), and modified materials of the above carbon materials, preferably one or more of activated carbon, single-walled carbon nanotubes, multi-walled carbon nanotubes, carbon nanofibers, carbon paper, graphene sheets, and carbon cloth, and more preferably one or more of activated carbon, carbon nanofibers, and graphene sheets.

In the present invention, the sulfide may be one or more of molybdenum disulfide, hexamolybdenum octasulfide, tungsten disulfide, vanadium disulfide, titanium disulfide, iron sulfide, ferrous sulfide, nickel sulfide, zinc sulfide, cobalt sulfide, trinickel disulfide, manganese sulfide, and cobalt nickel sulfide, which are conventionally used in the art.

In the present invention, the nitride may be a nitride conventionally used in the art, such as one or more of hexagonal boron nitride, carbon-doped hexagonal boron nitride, and vanadium nitride.

In the present invention, the oxide may be an oxide conventionally used in the art, such as molybdenum trioxide, tungsten trioxide, vanadium pentoxide, vanadium dioxide, titanium dioxide, zinc oxide, copper oxide, nickel oxide, niobium oxide, iron oxide, triiron tetroxide, cobalt oxide, tricobalt tetroxide, manganese oxide, trimanganese tetroxide, ruthenium oxide, iridium oxide, indium oxide, bismuth oxide, nickel cobalt oxide, nickel manganese oxide, nickel iron oxide, nickel molybdenum oxide, lithium titanate, lithium molybdate, M_xV₂O₅·nH₂O (M is a base)Metal), M_xV₃O₈(M is an alkali metal), M_xV₂O₇(M is an alkali metal), M_xVO₂(M is an alkali metal), M_xVO₄(M is an alkali metal) and M_xV₂O₁₆(M is an alkali metal).

In the present invention, the hydroxide may be one or more of hydroxides conventionally used in the art, such as nickel hydroxide, iron hydroxide, and cobalt hydroxide.

In the present invention, the selenide may be a selenide conventionally used in the art, for example, one or more of vanadium selenide, titanium selenide, molybdenum selenide, tungsten selenide, nickel selenide, and manganese selenide.

In the present invention, the carbide may be one or more carbides conventionally used in the art, such as titanium carbide, tantalum carbide, molybdenum carbide, and silicon carbide.

In the present invention, the transition metal cyanide may be one or more transition metal cyanides conventionally used in the art, such as zinc ferricyanide, cobalt ferricyanide, copper ferricyanide, iron ferricyanide and nickel ferricyanide.

In the present invention, the oxyhydroxide may be one or more of oxyhydroxides conventionally used in the art, such as iron oxyhydroxide, manganese oxyhydroxide, and cobalt oxyhydroxide.

In the present invention, the conductive polymer may be a conductive polymer conventionally used in the art, such as polyaniline, polypyrrole, polythiophene, poly 3, 4-ethylenedioxythiophene, quinone, and one or more of the above-mentioned conductive polymer derivatives.

In the invention, the MOF material is preferably one or more of ZIF-8, ZIF-67 and oxidized, vulcanized and other derivatives thereof.

In the present invention, the conductive agent may be a conductive agent conventionally used in the art, such as one or more of conductive carbon black (SuperP), acetylene black, ketjen black, conductive carbon spheres, conductive graphite, carbon nanotubes, carbon fibers, and graphene, and is preferably acetylene black.

In the present invention, the binder may be a binder conventionally used in the art, such as one or more of polyvinylidene fluoride, polytetrafluoroethylene, polyvinyl alcohol, carboxymethyl cellulose, Styrene Butadiene Rubber (SBR), and polyolefin, preferably polytetrafluoroethylene.

In the invention, the positive electrode active material preferably comprises 60-95% of the positive electrode active material by mass percent, and more preferably comprises 80% of the positive electrode active material by mass percent, wherein the percentage is the percentage of the total mass of the positive electrode material.

In the invention, the positive electrode material preferably contains 2-30% of a conductive agent by mass percent, and more preferably contains 10% of the conductive agent by mass percent, wherein the percentage is the percentage of the total mass of the positive electrode material.

In the invention, the cathode material preferably contains 3-10% of binder by mass percentage, and more preferably contains 10% of binder by mass percentage, wherein the percentage is the percentage of the total mass of the cathode material.

In the invention, the positive electrode material preferably comprises 60-95% of positive electrode active material, 2-30% of conductive agent and 3-10% of binder by mass percent, and more preferably comprises 80% of positive electrode active material, 10% of conductive agent and 10% of binder by mass percent, wherein the percentage is the percentage of the total mass of the positive electrode material.

In the invention, the positive current collector comprises a metal foil or a mesh material.

In the present invention, the metal in the positive electrode current collector may be a metal conventionally used in the art, such as any one or an alloy of at least two of chromium, nickel, aluminum, copper, tin, zinc, lead, antimony, cadmium, gold, titanium, bismuth, and germanium, or a metal matrix composite including any one.

In the present invention, the positive electrode current collector is preferably a nickel sheet and/or a nickel mesh, and more preferably a nickel mesh of 200 mesh or more.

In the present invention, the separator may be one or more of a separator conventionally used in the art, for example, a porous polymer film (e.g., a polyethylene film, a polypropylene film), an inorganic porous film (e.g., a glass fiber separator, a nonwoven fabric film), an organic/inorganic composite film (e.g., a porous ceramic separator).

In the invention, the negative electrode can be a negative electrode which is conventional in the field, preferably can be reversibly deposited and dissolved by zinc ions and zinc-containing ions or can be reversibly alloyed with zinc, and comprises a negative electrode material.

In the invention, the negative electrode material can be any one of the following schemes:

scheme 1: the negative electrode material comprises a self-supporting material;

scheme 2: the negative electrode material comprises a negative electrode active material, a conductive agent and a binder; the negative active material is powder;

wherein, the self-supporting material can be any one of the following schemes:

scheme 1.1: the self-supporting material comprises a negative active material, and the negative active material is a foil;

scheme 1.2: the self-supporting material comprises a highly conductive flexible substrate material comprising zinc.

In the present invention, the negative active material may be a negative active material conventional in the art, and preferably one or more of zinc, zinc oxide, zinc hydroxide, a zinc alloy, and a composite material of zinc and a nonmetal. The zinc alloy may be a zinc alloy conventional in the art, such as an alloy of zinc with one or more of lithium, sodium, potassium, calcium, iron, cobalt, nickel, magnesium, aluminum, copper, zinc, manganese, tin, antimony, lead, magnesium, gallium, indium, mercury, titanium, bismuth, chromium, and germanium, and such as one or more of a zinc-aluminum alloy, a zinc-copper alloy, and a zinc-magnesium alloy. The zinc and non-metal composite may be a composite conventional in the art, for example a composite of zinc and one or more of oxygen, sulphur, carbon and nitrogen.

In the present invention, when the negative electrode material includes a negative electrode active material, a conductive agent, and a binder, the conductive agent may be a conductive agent conventionally used in the art, such as one or more of acetylene black, mesocarbon microbeads, natural graphite, expanded graphite, artificial graphite, glassy carbon, a carbon-carbon composite, carbon fibers, hard carbon, soft carbon, activated carbon, porous carbon, carbon cloth, carbon paper, three-dimensional graphite, carbon black, carbon nanotubes, and graphene. The binder may be a binder conventionally used in the art, such as one or more of polyvinylidene fluoride, polytetrafluoroethylene, polyvinyl alcohol, carboxymethyl cellulose, SBR rubber, and polyolefin, preferably polytetrafluoroethylene.

In the present invention, when the negative electrode material includes a negative electrode active material, a conductive agent and a binder, the negative electrode material preferably includes 60 to 95% by mass of the negative electrode active material, wherein the percentage is a percentage of the total mass of the negative electrode material.

In the invention, when the negative electrode material comprises a negative electrode active material, a conductive agent and a binder, the negative electrode material preferably comprises 2-30% of the conductive agent by mass percent, wherein the percent is the percentage of the total mass of the negative electrode material.

In the present invention, when the negative electrode material includes a negative electrode active material, a conductive agent and a binder, the negative electrode material preferably includes 3 to 10% by mass of the binder, more preferably 10% by mass, wherein the percentage is a percentage of the total mass of the negative electrode material.

In the present invention, when the negative electrode material comprises a negative electrode active material, a conductive agent and a binder, the negative electrode material preferably comprises, by mass, 60 to 95% of the negative electrode active material, 2 to 30% of the conductive agent and 3 to 10% of the binder, wherein the percentages are percentages of the total mass of the negative electrode material.

In the present invention, when the negative electrode material includes a negative electrode active material, a conductive agent, and a binder, the negative electrode may further include a negative electrode current collector. The negative electrode current collector may be a negative electrode current collector conventional in the art, including a metal foil or mesh. The metal in the negative electrode current collector may be a metal conventional in the art, such as any one or an alloy of at least two of chromium, nickel, aluminum, copper, tin, zinc, lead, antimony, cadmium, gold, titanium, bismuth, and germanium, or a metal matrix composite including any one.

In the present invention, when the self-supporting material includes a zinc-containing highly conductive flexible base material, the highly conductive flexible base material may be a highly conductive flexible base material conventional in the art, including but not limited to a carbon cloth, a carbon paper, or a carbon foam material. The zinc-containing high-conductivity flexible base material generally refers to electroplating zinc on the surface of the high-conductivity flexible base material.

The derivatives described in the present invention refer to more complex products derived from a simple compound in which a hydrogen atom or group of atoms is replaced by another atom or group of atoms.

The Metal Matrix Composite (MMC) in the invention is a composite material which is artificially combined by taking metal and alloy thereof as a matrix and one or more metal or nonmetal reinforcing phases. The reinforcing material is inorganic nonmetal, such as ceramic, carbon, graphite, boron, and metal wire.

In the invention, the zinc-based hybrid supercapacitor refers to a hybrid supercapacitor which takes a material containing a zinc element as an electrode material and/or takes zinc ions and/or zinc-containing ions into work.

The above preferred conditions can be arbitrarily combined to obtain preferred embodiments of the present invention without departing from the common general knowledge in the art.

The reagents and starting materials used in the present invention are commercially available.

The positive progress effects of the invention are as follows:

(1) compared with the existing non-aqueous electrolyte and aqueous neutral electrolyte, the zinc-based hybrid supercapacitor adopting the aqueous alkaline electrolyte can maintain or obtain a wider electrochemical window on the basis of maintaining power density, has higher specific capacity and energy density, and shows high capacitance retention rate in a long-cycle effect test.

(2) The zinc-based hybrid supercapacitor prepared by the method has the advantages of wide application range, excellent performance, environmental friendliness and the like.

Drawings

FIG. 1 is a schematic structural diagram of a zinc-based hybrid supercapacitor according to example 1 of the present invention.

FIG. 2 is a schematic diagram of constant current charging and discharging of the zinc-based hybrid supercapacitor of example 1 of the present invention.

FIG. 3 is a schematic diagram of the energy density and power density of a zinc-based hybrid supercapacitor of example 1 of the present invention.

FIG. 4 is a graph of the long cycle test effect of the zinc-based hybrid supercapacitor of example 1 of the present invention.

The figure is as follows: 1-positive current collector; 2-a positive electrode material; 3-an electrolyte; 4-a separator; 5-negative electrode

Detailed Description

The invention is further illustrated by the following examples, which are not intended to limit the scope of the invention. The experimental methods without specifying specific conditions in the following examples were selected according to the conventional methods and conditions, or according to the commercial instructions.

In all the examples, the electrochemical workstation of Shanghai Chenghua CHI 760e was used, the test method was constant current charging and discharging, and the charging and discharging electrochemical windows are shown in tables 3 to 13.

Example 1

Preparing a positive electrode: preparing an electrode film from activated carbon (positive electrode active material), acetylene black (conductive agent) and polytetrafluoroethylene (binder) according to a mass ratio of 80:10:10, pressing the electrode film on a nickel net (positive electrode current collector) with the diameter of 15mm, and drying the electrode film to obtain a positive electrode plate;

preparing a negative electrode: polishing and cleaning metal zinc to prepare a wafer with the diameter of 18 mm;

preparing an electrolyte: sequentially dissolving potassium hydroxide and zinc sulfate in water to prepare electrolyte, wherein the concentration of the potassium hydroxide is 6mol/L, and the concentration of the zinc sulfate is 20 mmol/L;

preparing a diaphragm: the glass fiber diaphragm is made into a circular sheet with the diameter of 19 mm.

Assembling: and sequentially overlapping the positive plate, the diaphragm and the negative plate into a shell of the button cell, adding electrolyte, buckling the negative shell, and sealing to prepare the zinc-based hybrid supercapacitor.

Fig. 1 is a schematic structural diagram of a zinc-based hybrid supercapacitor of the embodiment.

FIG. 2 is a graph showing the charge and discharge curves of the zinc-based hybrid supercapacitor of this example, under the experimental conditions of constant current charge and discharge and a current density of 5A g^-1. As can be seen from FIG. 2, the maximum voltage of example 1 can reach 2.1V, and the electrochemical window is 0.2-2.1V.

FIG. 3 is a graph of energy density and power density of the zinc-based hybrid supercapacitor of this embodiment, and Table 1 is data corresponding to FIG. 3, from FIG. 3 and Table 1, it can be seen that the maximum power density of example 1 can reach 27600W kg^-1The maximum energy density can reach 175Wh kg^-1。

TABLE 1 energy Density and Power Density of Zinc-based hybrid supercapacitor

Current density (A g)^-1)	Energy Density (Wh kg)^-1)	Power density (W kg)^-1)
			2	175	1813
3	141	2668
			5	88	4050
10	66	7822
			20	46	14348
30	33	19672
			40	24	23784
50	19	27600

FIG. 4 is a long cycle test effect graph of the zinc-based hybrid supercapacitor of the embodiment. Table 2 shows the data corresponding to fig. 4.

TABLE 2 Long cycle test

Example 2

preparing a negative electrode: preparing a counter electrode film from zinc powder (a negative electrode active material), acetylene black (a conductive agent) and polytetrafluoroethylene (a binder) according to a mass ratio of 80:10:10, and pressing the counter electrode film on a stainless steel current collector with the diameter of 18mm to serve as a negative electrode;

The zinc-based hybrid supercapacitor of examples 3 to 5 are the same as example 1 except that the negative electrode material is different from example 1, and the other materials and preparation method are the same. As shown in table 3 below:

TABLE 3

Examples 6 to 11

The zinc-based hybrid supercapacitor of examples 6 to 11 were the same as example 1 except that the positive active material was different from example 1, and the remaining materials and preparation method were the same. As shown in table 4 below:

TABLE 4

Examples 12 to 17

The zinc-based hybrid supercapacitor of examples 12 to 17 were made by the same method and materials as example 1 except that the electrolyte used zinc salt was different from example 1. As shown in table 5 below:

TABLE 5

Examples 18 to 21

The zinc-based hybrid supercapacitor of examples 18 to 21 were the same as example 1 except that the electrolyte used alkali was different from example 1, and the materials and the preparation method were the same. As shown in table 6 below:

TABLE 6

Example 22

Preparing a positive electrode: preparing an electrode film from biomass activated carbon, acetylene black (conductive agent) and polytetrafluoroethylene (binder) according to a mass ratio of 80:10:10, pressing the electrode film on a nickel net (positive electrode current collector) with the diameter of 15mm, and drying the electrode film to obtain a positive electrode plate;

preparing an electrolyte: 10mL of water and 1g of polyvinyl alcohol are mixed and mixed uniformly, and then potassium hydroxide and zinc sulfate are added into the mixture to prepare the electrolyte, wherein the concentration of the potassium hydroxide is 1mol/L, and the concentration of the zinc sulfate is 0.02 mol/L.

Examples 23 to 24

The zinc-based hybrid supercapacitors of examples 23-24 were made using the same materials and methods as example 22, except that the electrolyte used was a polymer different from that used in example 22. As shown in table 7 below:

TABLE 7

Examples 25 to 28

The zinc-based hybrid supercapacitor of examples 25 to 28 were the same as example 1 except that the positive electrode conductive agent was different from example 1. As shown in table 8 below:

TABLE 8

Examples 29 to 31

The zinc-based hybrid supercapacitors of examples 29-31 were identical to example 1 in all materials and preparation methods, except that the separator was different from example 1. As shown in table 9 below:

TABLE 9

Example 32

preparing an electrolyte: sequentially dissolving potassium hydroxide and zinc sulfate in water to prepare electrolyte, wherein the concentration of the potassium hydroxide is 13mol/L, and the concentration of the zinc sulfate is 1 mmol/L;

Examples 33 to 36

The zinc-based hybrid supercapacitors of examples 33-36 were made using the same materials and methods as example 1, except that the concentration of zinc salt in the electrolyte was different from example 1. As shown in table 10 below:

watch 10

Examples 37 to 42

The zinc-based hybrid supercapacitors of examples 37-42 were made in the same manner as example 1, except that the concentration of potassium hydroxide in the electrolyte was different from example 1. As shown in table 11 below:

TABLE 11

Examples 43 to 45

The zinc-based hybrid supercapacitors of examples 43-45 were made using the same materials and methods as example 22, except that the volume of solvent water was different from that of example 22. As shown in table 12 below:

TABLE 12

Example 46

preparing an electrolyte: 10mL of tetrahydrofuran and 1g of polyvinyl chloride are mixed and mixed uniformly, a polymer solution is dripped on a glass plate, a film is formed by a scraper, then the film is cut into a circular sheet with the thickness of 19mm after being dried, and finally the circular sheet is immersed in a solution of potassium hydroxide and zinc sulfate to prepare the polymer film, wherein the concentration of the potassium hydroxide is 1mol/L, and the concentration of the zinc sulfate is 0.02 mol/L.

Assembling: and sequentially overlapping the positive plate, the polymer film and the negative plate into a button battery shell, buckling the button battery shell into the negative shell, and sealing to prepare the zinc-based hybrid supercapacitor.

Example 47

preparing an electrolyte: heating 10mL of dimethylformamide and 1g of polymethyl methacrylate to 60 ℃, mixing and uniformly mixing, dripping a polymer solution on a glass plate, scraping the mixture into a film by using a scraper, drying the film, cutting the film into 19mm round pieces, and finally soaking the round pieces into a solution of potassium hydroxide and zinc sulfate to prepare the polymer film, wherein the concentration of the potassium hydroxide is 1mol/L, and the concentration of the zinc sulfate is 0.02 mol/L.

Example 48

preparing an electrolyte: heating 10mL of dimethylformamide and 1g of polyvinylimidazole to 60 ℃, mixing and uniformly mixing, dripping a polymer solution on a glass plate, scraping the solution into a film by using a scraper, drying the film, cutting the film into 19mm round pieces, and finally soaking the round pieces into a solution of potassium hydroxide and zinc sulfate to prepare the polymer film, wherein the concentration of the potassium hydroxide is 1mol/L, and the concentration of the zinc sulfate is 0.02 mol/L.

Example 49

preparing an electrolyte: heating 10mL of water, 0.5g of polyvinyl alcohol and 0.5g of polyacrylic acid to 90 ℃, mixing uniformly, dripping a polymer solution on a glass plate, scraping the mixture into a film by using a scraper, drying the film, cutting the film into 19mm round pieces, and finally soaking the round pieces into a solution of potassium hydroxide and zinc sulfate to prepare the polymer film, wherein the concentration of the potassium hydroxide is 1mol/L, and the concentration of the zinc sulfate is 0.02 mol/L.

Example 50

The zinc-based hybrid supercapacitor of example 50 was made with the same materials and method as example 49 except that the electrolyte used was different from the polymer used in example 49. As shown in table 13 below:

watch 13

Note: electrochemical performance of examples 2-50 at a current density of 5A g^-1Wherein the measured energy density is the energy density of the positive electrode active material.

Comparative example 1

CN103545123A hybrid electrochemical capacitor as described in example 1.

Comparative example 2

CN103560019A hybrid electrochemical capacitor as described in example 1.

Comparative example 3

The zinc-based hybrid supercapacitor of the comparative example is the same as example 1 in all materials and preparation methods except that the electrolyte is different from example 1. The electrolyte is prepared as follows:

dissolving zinc sulfate in water to prepare electrolyte, wherein the concentration of the zinc sulfate is 20 mmol/L.

Comparative example 4

The zinc-based hybrid supercapacitor of the comparative example is the same as example 1 in all materials and preparation methods except that the electrolyte is different from example 1. In example 1, the concentration of potassium hydroxide was changed to 15 mol/L.

The electrochemical properties of example 1 and comparative examples 1-4 are shown in table 14 below:

TABLE 14

Note: the energy density is the energy density of the positive electrode active material. The electrochemical performance of example 1, comparative examples 3 and 4 was 5A g^-1Measured under the conditions of (1).

Claims

1. The application of the aqueous alkaline electrolyte in the preparation of the electrolyte of the zinc-based hybrid supercapacitor is characterized in that the aqueous alkaline electrolyte comprises alkali and water, the alkali is alkali metal hydroxide and/or alkali metal acetate, and the concentration of the alkali is 0.1-13 mol/L.

2. The use according to claim 1, wherein the alkali metal hydroxide is one or more of lithium hydroxide, sodium hydroxide and potassium hydroxide;

and/or the alkali metal acetate is one or more of lithium acetate, sodium acetate and potassium acetate;

and/or the concentration of the alkali is 1-10mol/L, preferably 3-7mol/L, more preferably 5-7 mol/L;

and/or the water is deionized water.

3. The use according to claim 1, wherein the aqueous alkaline electrolyte further comprises a zinc salt, preferably one or more of zinc triflate, zinc bis (trifluoromethylsulfonyl) imide, zinc tetrafluoroborate, zinc hexafluorophosphate, zinc hexafluoroarsenate, zinc perchlorate, zinc chlorate, zinc phosphate, zinc nitrate, zinc sulfate, zinc acetate and zinc chloride;

the concentration of the zinc salt is preferably 0.001 to 0.5mol/L, more preferably 0.01 to 0.06mol/L, further preferably 0.01 to 0.03 mol/L;

the molar concentration ratio of the alkali to the zinc salt is preferably 5-13000:1, more preferably 100-.

4. The use according to any one of claims 1 to 3, wherein the aqueous alkaline electrolyte further comprises a polymer, preferably one or more of polyethylene oxide, polyvinyl chloride, polyacrylonitrile, polymethyl methacrylate, polytetrafluoroethylene, polyvinyl alcohol, polyacrylic acid, polyvinyl imidazole, polyhydroxypropylacrylate, polyvinyl imidazole-hydroxypropyl acrylate, polydopamine and poly sodium alginate;

the mass-to-volume ratio of the polymer to the water is preferably 1:8 to 1:20g/mL, more preferably 1:10 to 1:20 g/mL.

5. The use according to claim 1, wherein the aqueous alkaline electrolyte is any one of the following:

the first scheme is as follows: the water system alkaline electrolyte is a mixed solution consisting of alkali and water, and the alkali is one or more of lithium hydroxide, sodium hydroxide and potassium hydroxide;

scheme II: the aqueous alkaline electrolyte is a mixed solution consisting of alkali and water, the concentration of the alkali is 3-7mol/L, and the alkali is one or more of lithium hydroxide, sodium hydroxide and potassium hydroxide;

the third scheme is as follows: the aqueous alkaline electrolyte is a mixed solution consisting of alkali and water, the concentration of the alkali is 5-7mol/L, and the alkali is one or more of lithium hydroxide, sodium hydroxide and potassium hydroxide;

and the scheme is as follows: the water system alkaline electrolyte is a mixed solution consisting of zinc salt, alkali and water; the zinc salt is one or more of zinc sulfate, zinc acetate, zinc nitrate and zinc chloride, and the alkali is one or more of lithium hydroxide, sodium hydroxide and potassium hydroxide; the concentration of the zinc salt is 0.001-0.5mol/L, and the molar concentration ratio of the alkali to the zinc salt is 5-13000: 1;

and a fifth scheme: the water system alkaline electrolyte is a mixed solution consisting of zinc salt, alkali and water; the zinc salt is one or more of zinc sulfate, zinc acetate, zinc nitrate and zinc chloride, and the alkali is one or more of lithium hydroxide, sodium hydroxide and potassium hydroxide; the concentration of the zinc salt is 0.001-0.5mol/L, and the molar concentration ratio of the alkali to the zinc salt is more than 100-13000: 1;

scheme six: the water system alkaline electrolyte is a mixed solution consisting of zinc salt, alkali and water; the zinc salt is one or more of zinc sulfate, zinc acetate, zinc nitrate and zinc chloride, and the alkali is one or more of lithium hydroxide, sodium hydroxide and potassium hydroxide; the concentration of the zinc salt is 0.001-0.5mol/L, and the molar concentration ratio of the alkali to the zinc salt is more than 100-7000: 1;

the scheme is seven: the water system alkaline electrolyte is a mixed solution consisting of zinc salt, alkali and water; the zinc salt is zinc sulfate, and the alkali is one or more of lithium hydroxide, sodium hydroxide and potassium hydroxide; the concentration of the alkali is 1-10mol/L, the concentration of the zinc salt is 0.01-0.5mol/L, and the molar concentration ratio of the alkali to the zinc salt is 120-1000: 1;

and the eighth scheme is as follows: the water system alkaline electrolyte is a mixed solution consisting of zinc salt, alkali and water; the zinc salt is zinc sulfate, and the alkali is one or more of lithium hydroxide, sodium hydroxide and potassium hydroxide; the concentration of the alkali is 3-7mol/L, the concentration of the zinc salt is 0.01-0.06mol/L, and the molar concentration ratio of the alkali to the zinc salt is 150-600: 1;

the scheme is nine: the water system alkaline electrolyte is a mixed solution consisting of zinc salt, alkali and water; the zinc salt is zinc sulfate, and the alkali is one or more of lithium hydroxide, sodium hydroxide and potassium hydroxide; the concentration of the alkali is 3-7mol/L, the concentration of the zinc salt is 0.01-0.03mol/L, and the molar concentration ratio of the alkali to the zinc salt is 150-350: 1;

and a scheme ten: the aqueous alkaline electrolyte is an electrolyte consisting of zinc salt, alkali, water and a polymer; the zinc salt is one or more of zinc sulfate, zinc acetate, zinc nitrate and zinc chloride, the alkali is one or more of lithium hydroxide, sodium hydroxide and potassium hydroxide, and the polymer is one or more of polyethylene oxide, polyvinyl chloride, polymethyl methacrylate, polyvinyl alcohol and polyacrylic acid; the concentration of the zinc salt is 0.001-0.5mol/L, the molar concentration ratio of the alkali to the zinc salt is 5-13000:1, and the mass-volume ratio of the polymer to the water is 1:8-1:20 g/mL;

scheme eleven: the aqueous alkaline electrolyte is an electrolyte consisting of zinc salt, alkali, water and a polymer; the zinc salt is one or more of zinc sulfate, zinc acetate, zinc nitrate and zinc chloride, the alkali is one or more of lithium hydroxide, sodium hydroxide and potassium hydroxide, and the polymer is one or more of polyethylene oxide, polyvinyl chloride, polymethyl methacrylate, polyvinyl alcohol and polyacrylic acid; the concentration of the zinc salt is 0.001-0.5mol/L, the molar concentration ratio of the alkali to the zinc salt is 100-13000:1, and the mass-volume ratio of the polymer to the water is 1:8-1:20 g/mL;

scheme twelve: the aqueous alkaline electrolyte is an electrolyte consisting of zinc salt, alkali, water and a polymer; the zinc salt is one or more of zinc sulfate, zinc acetate, zinc nitrate and zinc chloride, the alkali is one or more of lithium hydroxide, sodium hydroxide and potassium hydroxide, and the polymer is one or more of polyethylene oxide, polyvinyl chloride, polymethyl methacrylate, polyvinyl alcohol and polyacrylic acid; the concentration of the zinc salt is 0.001-0.5mol/L, the molar concentration ratio of the alkali to the zinc salt is 100-7000:1, and the mass-volume ratio of the polymer to the water is 1:8-1:20 g/mL;

scheme thirteen: the aqueous alkaline electrolyte is an electrolyte consisting of zinc salt, alkali, water and a polymer; the zinc salt is zinc sulfate, the alkali is one or more of lithium hydroxide, sodium hydroxide and potassium hydroxide, and the polymer is one or more of polyoxyethylene, polyvinyl chloride, polymethyl methacrylate, polyvinyl alcohol and polyacrylic acid; the concentration of the alkali is 1-10mol/L, the concentration of the zinc salt is 0.01-0.5mol/L, the molar concentration ratio of the alkali to the zinc salt is 120-1000:1, and the mass-volume ratio of the polymer to the water is 1:8-1:20 g/mL;

a fourteen scheme: the aqueous alkaline electrolyte is an electrolyte consisting of zinc salt, alkali, water and a polymer; the zinc salt is zinc sulfate, the alkali is one or more of lithium hydroxide, sodium hydroxide and potassium hydroxide, and the polymer is one or more of polyoxyethylene, polyvinyl chloride, polymethyl methacrylate, polyvinyl alcohol and polyacrylic acid; the concentration of the alkali is 3-7mol/L, the concentration of the zinc salt is 0.01-0.06mol/L, the molar concentration ratio of the alkali to the zinc salt is 150-600:1, and the mass-volume ratio of the polymer to the water is 1:8-1:20 g/mL;

and, scheme fifteen: the aqueous alkaline electrolyte is an electrolyte consisting of zinc salt, alkali, water and a polymer; the zinc salt is zinc sulfate, the alkali is one or more of lithium hydroxide, sodium hydroxide and potassium hydroxide, and the polymer is polyvinyl alcohol; the concentration of the alkali is 3-7mol/L, the concentration of the zinc salt is 0.01-0.03mol/L, the molar concentration ratio of the alkali to the zinc salt is 150-350:1, and the mass-volume ratio of the polymer to the water is 1:10-1:20 g/mL.

6. The aqueous alkaline electrolyte is characterized by comprising alkali, zinc salt and water, wherein the alkali is alkali metal hydroxide and/or alkali metal acetate, the concentration of the alkali is 0.1-13mol/L, and the molar concentration ratio of the alkali to the zinc salt is more than 100:1 and less than or equal to 13000: 1.

7. The aqueous alkaline electrolyte of claim 6 wherein the alkali metal hydroxide is one or more of lithium hydroxide, sodium hydroxide and potassium hydroxide;

and/or the zinc salt is one or more of zinc trifluoromethanesulfonate, zinc bis (trifluoromethylsulfonyl) imide, zinc tetrafluoroborate, zinc hexafluorophosphate, zinc hexafluoroarsenate, zinc perchlorate, zinc chlorate, zinc phosphate, zinc nitrate, zinc sulfate, zinc acetate and zinc chloride;

and/or the concentration of the zinc salt is more than or equal to 0.001mol/L and less than 0.13mol/L, preferably more than or equal to 0.01mol/L and less than 0.13mol/L, more preferably 0.01-0.06mol/L, and further preferably 0.01-0.03 mol/L;

and/or the molar concentration ratio of the base to the zinc salt is more than 100:1 and less than or equal to 7000:1, preferably 120-6000:1, preferably 120-1000:1, more preferably 150-600:1, more preferably 150-350:1, and even more preferably 250-300: 1;

and/or the water is deionized water.

8. The aqueous alkaline electrolyte of claim 6 further comprising a polymer, wherein the polymer is one or more of polyethylene oxide, polyvinyl chloride, polyacrylonitrile, polymethyl methacrylate, polytetrafluoroethylene, polyvinyl alcohol, polyacrylic acid, polyvinyl imidazole, polyhydroxypropylacrylate, polyvinyl imidazole-hydroxypropyl acrylate, polydopamine, and poly sodium alginate;

9. The aqueous alkaline electrolyte of claim 6, wherein the aqueous alkaline electrolyte is one of the following:

the first scheme is as follows: the water system alkaline electrolyte is a mixed solution consisting of zinc salt, alkali and water; the zinc salt is one or more of zinc sulfate, zinc acetate, zinc nitrate and zinc chloride, and the alkali is one or more of lithium hydroxide, sodium hydroxide and potassium hydroxide; the concentration of the zinc salt is more than or equal to 0.001mol/L and less than 0.13 mol/L;

scheme II: the water system alkaline electrolyte is a mixed solution consisting of zinc salt, alkali and water; the zinc salt is zinc sulfate, and the alkali is one or more of lithium hydroxide, sodium hydroxide and potassium hydroxide; the concentration of the alkali is 1-10mol/L, the concentration of the zinc salt is 0.01-0.06mol/L, and the molar concentration ratio of the alkali to the zinc salt is more than 100:1 and less than or equal to 7000: 1;

the third scheme is as follows: the water system alkaline electrolyte is a mixed solution consisting of zinc salt, alkali and water; the zinc salt is zinc sulfate, and the alkali is one or more of lithium hydroxide, sodium hydroxide and potassium hydroxide; the concentration of the alkali is 1-10mol/L, the concentration of the zinc salt is 0.01-0.06mol/L, and the molar concentration ratio of the alkali to the zinc salt is 150-600: 1;

and the scheme is as follows: the water system alkaline electrolyte is a mixed solution consisting of zinc salt, alkali and water; the zinc salt is zinc sulfate, and the alkali is one or more of lithium hydroxide, sodium hydroxide and potassium hydroxide; the concentration of the alkali is 3-7mol/L, the concentration of the zinc salt is 0.01-0.03mol/L, and the molar concentration ratio of the alkali to the zinc salt is 150-600: 1;

and a fifth scheme: the aqueous alkaline electrolyte is an electrolyte consisting of zinc salt, alkali, water and a polymer; the zinc salt is one or more of zinc sulfate, zinc acetate, zinc nitrate and zinc chloride, the alkali is one or more of lithium hydroxide, sodium hydroxide and potassium hydroxide, and the polymer is one or more of polyethylene oxide, polyvinyl chloride, polymethyl methacrylate, polyvinyl alcohol and polyacrylic acid; the concentration of the zinc salt is more than or equal to 0.001mol/L and less than 0.13mol/L, and the mass-volume ratio of the polymer to the water is 1:8-1:20 g/mL;

scheme six: the aqueous alkaline electrolyte is an electrolyte consisting of zinc salt, alkali, water and a polymer; the zinc salt is zinc sulfate, the alkali is one or more of lithium hydroxide, sodium hydroxide and potassium hydroxide, and the polymer is one or more of polyoxyethylene, polyvinyl chloride, polymethyl methacrylate, polyvinyl alcohol and polyacrylic acid; the concentration of the alkali is 1-10mol/L, the concentration of the zinc salt is 0.01-0.06mol/L, the molar concentration ratio of the alkali to the zinc salt is more than 100:1 and less than or equal to 7000:1, and the mass-volume ratio of the polymer to the water is 1:8-1:20 g/mL;

the scheme is seven: the aqueous alkaline electrolyte is an electrolyte consisting of zinc salt, alkali, water and a polymer; the zinc salt is zinc sulfate, the alkali is one or more of lithium hydroxide, sodium hydroxide and potassium hydroxide, and the polymer is one or more of polyoxyethylene, polyvinyl chloride, polymethyl methacrylate, polyvinyl alcohol and polyacrylic acid; the concentration of the alkali is 1-10mol/L, the concentration of the zinc salt is 0.01-0.06mol/L, the molar concentration ratio of the alkali to the zinc salt is 150-600:1, and the mass-volume ratio of the polymer to the water is 1:8-1:20 g/mL;

and, scheme eight: the aqueous alkaline electrolyte is an electrolyte consisting of zinc salt, alkali, water and a polymer; the zinc salt is zinc sulfate, the alkali is one or more of lithium hydroxide, sodium hydroxide and potassium hydroxide, and the polymer is polyvinyl alcohol; the concentration of the alkali is 3-7mol/L, the concentration of the zinc salt is 0.01-0.03mol/L, the molar concentration ratio of the alkali to the zinc salt is 150-600:1, and the mass-volume ratio of the polymer to the water is 1:10-1:20 g/mL.

10. A zinc-based hybrid supercapacitor, characterized in that it comprises an aqueous alkaline electrolyte; the aqueous alkaline electrolyte is as defined in any one of claims 1 to 5.

11. A method of making a zinc-based hybrid supercapacitor as claimed in claim 10, wherein when the aqueous alkaline electrolyte does not include a polymer, the method of making comprises the steps of: assembling the positive electrode, the separator, the negative electrode and the aqueous alkaline electrolyte;

when the aqueous alkaline electrolyte includes a polymer, the preparation method is any one of the following methods:

the method comprises the following steps: assembling the positive electrode, the separator, the negative electrode and the aqueous alkaline electrolyte;