Aqueous zinc-ion battery and electrolyte and preparation method thereof

Abstract

This invention discloses an aqueous zinc-ion battery, its electrolyte, and a preparation method thereof. The carbon quantum dot additive in the electrolyte is prepared via a solvent synthesis method. The electrolyte solvent is a mixture of water and an organic solvent coupled with carbon quantum dots, and the solute is a zinc salt (ZnX). a ), wherein the organic solvent is one or more of methanol, ethanol, isopropanol, acetone, and dimethylformamide; X = Cl ‑ SO4 2‑ NO3 ‑ CH3COO ‑ CF3SO3 ‑ ClO4 ‑ One or more of the following are used: The zinc anode comprises zinc sheet, zinc foil, zinc powder, zinc mesh, porous zinc, or zinc alloy. The zinc anode operating in this electrolyte exhibits excellent deposition-dissolution reversibility, and the cycled zinc sheet shows characteristics of dense deposition, absence of dendrites and byproducts. This method is simple, low-cost, and can significantly improve the cycle stability of the zinc anode in aqueous zinc-ion batteries.

Description

Technical Field

[0001] This invention relates to a negative electrode protection method that improves the reversibility of zinc dissolution and deposition in zinc-ion batteries by coupling and regulating additives and electrolytes, and belongs to the field of electrochemistry. Background Technology

[0002] Against the backdrop of finite fossil fuel reserves and rising carbon dioxide emissions leading to global warming, the government has established "dual carbon" targets such as "carbon peaking" and "carbon neutrality," promoting the increasing importance of renewable and clean energy. However, renewable energy sources (such as solar and wind power) require highly secure, low-cost, and long-life energy storage technologies to ensure stable energy output due to their intermittent, fluctuating, random, and geographically dependent characteristics. Compared to traditional mechanical, electromagnetic, thermal, and chemical energy storage, electrochemical energy storage (i.e., various secondary battery energy storage) is considered to play a crucial role in the future energy storage market due to its flexible configuration, rapid response, and short construction period. Currently, lithium-ion batteries dominate electrochemical energy storage (approximately 88%). However, lithium is expensive (US$19.2 / kg), and lithium-ion batteries use organic electrolytes, posing serious safety hazards; leaks or overheating can easily lead to fires and explosions. Therefore, there is an urgent need to develop low-cost, highly safe electrochemical energy storage technologies.

[0003] my country possesses abundant zinc reserves (the largest in the world), offering advantages such as low cost ($2.4 / kg), non-toxicity, and high theoretical capacity (5851 mAh / mL; 820 mAh / g). Zinc's relatively low redox potential (-0.76 volts relative to the standard hydrogen electrode) allows zinc-ion batteries to directly utilize aqueous electrolytes. Compared to organic electrolytes, aqueous electrolytes have approximately two orders of magnitude higher ionic conductivity (approximately 1000 mSiemens / cm vs. approximately 1-10 mSiemens / cm), enabling rapid charge-discharge in aqueous zinc-ion batteries. Furthermore, thanks to the relatively stable chemical and physical properties of zinc, aqueous zinc-ion batteries pose no risk of explosion or fire, making them highly safe and promising for applications in portable devices, electric vehicles, and large-scale energy storage.

[0004] However, current aqueous zinc-ion batteries face key challenges such as dendrite formation and side reactions, which can easily lead to electrode failure or low cycle life. Zinc dendrites can easily puncture the separator, causing short circuits, and can also lead to uneven electrode thickness and electrode deformation. Side reactions (including water corrosion and hydrogen evolution reactions) not only reduce zinc utilization and battery coulombic efficiency, but the generation of hydrogen also affects battery safety and electrochemical performance. Therefore, effectively suppressing zinc dendrite formation and side reactions is a crucial problem that must be solved in the development of zinc-ion batteries. Summary of the Invention

[0005] The purpose of this invention is to improve the cycle stability of the zinc-ion battery anode by avoiding zinc dendrites and side reactions. This invention provides a zinc anode protection method that uses the coupling effect between carbon quantum dots and a specific solvent to suppress dendrites and byproducts, thereby improving the reversibility of zinc anode dissolution and deposition in zinc-ion batteries. Specifically, by adjusting the concentration of carbon quantum dots in the electrolyte system and the ratio and type of the coupled organic solvent, the deposition behavior of zinc is guided at the electrode / solution interface on the zinc anode side of the zinc-ion battery, enabling reversible deposition and dissolution of the zinc anode. Battery cycle performance results show that the zinc anode preferentially deposits along the (002) crystal plane in the regulated electrolyte, without the generation of zinc dendrites and byproducts, exhibiting efficient and reversible deposition / dissolution performance; the method is simple and low-cost.

[0006] This invention uses zinc-based materials as the zinc anode active material, carbon quantum dots as the electrolyte additive, water or a mixture of water and organic solvent as the electrolyte solvent, and zinc salt (ZnX) as the solute. a The present invention uses carbon quantum dots to form a coupling effect with a specific solvent to suppress dendrites and byproducts.

[0007] This invention provides an electrolyte containing carbon quantum dots for protecting the zinc anode in a zinc-ion battery. The electrolyte uses hydrophobic carbon quantum dots as an electrolyte additive, and the solvent of the electrolyte is a mixture of water and an organic solvent, with the solute being a zinc salt. The organic solvent is one or more of methanol, ethanol, isopropanol, acetone, and dimethylformamide.

[0008] Furthermore, in the above technical solution, the volume ratio of the organic solvent to water is 0 to 1, and is not zero, that is, greater than 0 and less than or equal to 1;

[0009] Furthermore, in the above technical solution, the method for preparing the hydrophobic carbon quantum dots includes the following steps:

[0010] 1) Use a small molecule organic solvent A, wherein A is one or more of methanol, ethanol, acetic acid, acetonitrile, acetone, butanone, ethylene glycol, formaldehyde, and acetaldehyde;

[0011] 2) The strong alkali powder B(OH) added to 1) a Where B is one or more of Li, Na, Ka, Be, Mg, Ca, and Sr, and a = 1 to 2; small molecule organic solvents react with strong base powder B(OH). a The dosage ratio is 10-100 mL : 1-40 g;

[0012] 3) Stir the solid-liquid mixture obtained in step 2) at a speed of 100-1500 rpm for 10-200 min, and let it stand for 1-50 days;

[0013] 4) Neutralize the product obtained in step 3) with 0.1-10M hydrochloric acid or sulfuric acid to pH=7;

[0014] 5) Separate the carbon quantum dot enriched phase from the product obtained in step 4) and wash it with deionized water 2 to 20 times;

[0015] 6) The product obtained in step 5) is dried under vacuum at 60-200℃ for 12-48 hours.

[0016] Furthermore, in the above technical solution, the solute zinc salt has the structural formula ZnX. a , where X = Cl - SO4 2- NO3 - CH3COO - CF3SO3 - ClO4 - One or more of the following, a = 1 to 2; the zinc salt ZnX a The concentration is 0.1–5 M.

[0017] The present invention provides a method for preparing the above-mentioned electrolyte, comprising the following steps:

[0018] (1) Carbon quantum dot powder is dissolved in a certain amount of organic solvent, wherein the organic solvent is one or more of methanol, ethanol, benzyl alcohol, phenol, propanol, benzene, isopropanol, acetonitrile, propionitrile, isopropionitrile, formaldehyde, acetaldehyde, propionitrile, acetone, butanone, formic acid, acetic acid, dimethyl sulfoxide, and dimethylformamide, and the concentration of carbon quantum dots is 0 to 50 mg / mL, and cannot be 0;

[0019] (2) A certain amount of zinc salt ZnX a Dissolves in aqueous solution, where X = Cl - SO4 2- NO3 - CH3COO - CF3SO3 - ClO4 - One or more of the following, a = 1 to 2; the zinc salt ZnX a Concentrations range from 0.1 to 6 M;

[0020] (3) Add the organic dispersion of carbon quantum dots from step (1) to the electrolyte from step (2), stir until a clear liquid is formed, and sonicate for 10 to 500 minutes.

[0021] (4) Let the liquid obtained in step (3) stand for 0 to 5 days, and the liquid temperature is not zero. Then filter it to obtain a clear electrolyte.

[0022] This invention provides a zinc-ion battery, characterized in that it contains the above-mentioned electrolyte and uses a zinc-based material as the zinc negative electrode active material.

[0023] Furthermore, in the above technical solution, the zinc negative electrode is a zinc sheet, zinc foil, zinc powder, zinc mesh, porous zinc, or zinc alloy.

[0024] The reversibility of zinc anode deposition and dissolution in the electrolyte prepared in this invention was evaluated using a zinc symmetric cell, as follows:

[0025] Two zinc anodes are placed in their corresponding positions within the battery mold, with a separator between them to isolate electron transport. Electrolyte is then added, and the zinc anode symmetrical battery is encapsulated using a button cell sealing machine. The encapsulated battery is then connected to an electrochemical charge-discharge apparatus and charged at a specified current density (0.1–20 mA / cm²). 2 Cyclic stability tests were performed under these conditions.

[0026] Beneficial results:

[0027] The carbon quantum dots synthesized in this invention have a size of less than 5 nm (transmission electron microscopy image shown). Figure 1 As shown), the electrolyte, after being coupled with an organic solvent, can induce strong preferential growth of zinc on the (002) crystal plane (2θ = 36°) during zinc deposition. XRD test results show that the strongest peak of the zinc sheet after cycling corresponds to the (002) crystal plane of zinc (the strongest XRD peak of the initial zinc (2θ = 43°) corresponds to the (101) crystal plane), and there is no XRD peak of the byproduct Zn4(OH)6SO4·xH2O (XRD results are shown in Figure 1). Figure 2 (As shown); Scanning electron microscopy (SEM) images of the zinc surface after 800 hours of cycling showed no zinc dendrites or byproducts (SEM results are shown in the image). Figure 1 (As shown). The zinc symmetric cell exhibits excellent zinc deposition-dissolution reversibility, with symmetrical, stable, and flat voltage-time curves; at 0.5 mA / cm²... 2 At current densities, the cycle life can reach 1400 hours (the voltage-time curve of the battery cycle test is shown in Figure 1). Figure 3 (As shown).

[0028] The method provided by this invention is time-saving, simple in steps, low in cost, and highly repeatable. Attached Figure Description

[0029] Figure 1 Transmission electron microscopy images of the carbon quantum dots used in Examples 1-8

[0030] Figure 2 These are scanning electron microscope images of the zinc surface after battery cycling in Examples 1-8.

[0031] Figure 3The image shows the X-ray diffraction (XRD) pattern of the zinc foil after battery cycling in Example 1.

[0032] Figure 4 The voltage-time curve is the battery cycle test result from Example 1.

[0033] Figure 5 A scanning electron microscope image of the zinc surface after battery cycling in Comparative Example 1.

[0034] Figure 6 The X-ray diffraction (XRD) pattern of the zinc foil after battery cycling in Comparative Example 1 is shown.

[0035] Figure 7 A scanning electron microscope image of the zinc surface after battery cycling in Comparative Example 3.

[0036] Figure 8 The X-ray diffraction (XRD) pattern of the zinc foil after battery cycling in Comparative Example 3 is shown. Detailed Implementation

[0037] The following embodiments will further illustrate the present invention, but are not intended to limit the invention.

[0038] Example 1

[0039] Synthesis of carbon quantum dots:

[0040] 8g of NaOH powder was added to 40mL of acetone, and the mixture was magnetically stirred at 800rpm for 90min, then sealed and allowed to stand for 5 days to obtain a black solid mixture. 1M hydrochloric acid was added to the mixture until the pH reached 7. The mixture exhibited stratification, with the upper layer being a carbon quantum dot-enriched phase. After washing the enriched phase 10 times with deionized water, the carbon quantum dot-enriched phase was vacuum-dried at 100℃ for 24h to obtain hydrophobic carbon quantum dot powder. Electrolyte preparation scheme:

[0041] Weigh 20 mg of synthesized carbon quantum dot powder and dissolve it in 2 mL of ethanol; weigh 11.5 g of ZnSO4·7H2O powder and dissolve it in 20 mL of deionized water. Add the ethanol dispersion of carbon quantum dots to zinc sulfate solution, sonicate for 1 h, let stand for 1 day, and then filter to obtain a clear electrolyte.

[0042] Battery assembly and results:

[0043] Zinc-ion symmetric batteries were assembled using commercial zinc foil and the electrolyte. The assembly steps are as follows: Two zinc anodes were placed in their corresponding positions within the battery mold, with a separator to isolate electron transport placed between them. The electrolyte was then added, and the zinc anode symmetric battery was encapsulated using a button cell sealing machine. The encapsulated battery was then connected to an electrochemical charge-discharge apparatus.

[0044] At 0.5mA / cm2 At current density, the zinc surface after battery cycling exhibits a preferred orientation of (002) planes. The zinc surface morphology is shown in [reference needed]. Figure 2 The X-ray diffraction (XRD) spectra of zinc after battery cycling are shown in the figure. Figure 3 The battery achieved a stable cycle time of 1400 hours. The voltage-time curve for the battery cycle test is shown below. Figure 4 .

[0045] Example 2

[0046] The synthesis steps of carbon quantum dots are as shown in Example 1.

[0047] Electrolyte preparation scheme:

[0048] Weigh 1 mg of synthesized carbon quantum dot powder and dissolve it in 1 mL of isopropanol; weigh 5.4 g of ZnCl2 powder and dissolve it in 20 mL of deionized water. Add the isopropanol dispersion of carbon quantum dots to zinc chloride solution, sonicate for 1 h, let stand for 1 day, and then filter to obtain a clear electrolyte.

[0049] Battery assembly and results:

[0050] A zinc-ion symmetric battery was assembled using zinc-aluminum alloy sheets and the electrolyte according to the steps of Example 1, at 2 mA / cm². 2 At the current density, the zinc surface after battery cycling exhibits a preferred orientation of (002) planes. The zinc surface morphology is shown in [reference needed]. Figure 2 .

[0051] Example 3

[0052] The synthesis steps of carbon quantum dots are as shown in Example 1.

[0053] Electrolyte preparation scheme:

[0054] 80 mg of synthesized carbon quantum dot powder was weighed and dissolved in 10 mL of dimethylformamide; 11.9 g of Zn(NO3)2·6H2O powder was weighed and dissolved in 20 mL of deionized water. The dimethylformamide dispersion of carbon quantum dots was added to zinc nitrate solution and sonicated for 1 h. After standing for 1 day, the solution was filtered to obtain a clear electrolyte.

[0055] Battery assembly and results:

[0056] Zinc-ion symmetric cells were assembled using zinc powder supported by a stainless steel mesh and the electrolyte, following the steps of Example 1. At 2 mA / cm²... 2 At the current density, the zinc surface after battery cycling exhibits a preferred orientation of (002) planes. The zinc surface morphology is shown in [reference needed]. Figure 2 .

[0057] Example 4

[0058] The synthesis steps of carbon quantum dots are as shown in Example 1.

[0059] Electrolyte preparation scheme:

[0060] 90 mg of synthesized carbon quantum dot powder was weighed and dissolved in 10 mL of ethanol; 8.8 g of Zn(CH3COO)2·2H2O powder was weighed and dissolved in 40 mL of deionized water. The ethanol dispersion of carbon quantum dots was added to zinc acetate solution and sonicated for 1 h. After standing for 1 day, the solution was filtered to obtain a clear electrolyte.

[0061] Battery assembly and results:

[0062] Zinc-ion symmetric cells were assembled using zinc powder supported by a stainless steel mesh and the electrolyte, following the steps of Example 1. At 2 mA / cm²... 2 At the current density, the zinc surface after battery cycling exhibits a preferred orientation of (002) planes. The zinc surface morphology is shown in [reference needed]. Figure 2 .

[0063] Example 5

[0064] The synthesis steps of carbon quantum dots are as shown in Example 1.

[0065] Electrolyte preparation scheme:

[0066] 250 mg of synthesized carbon quantum dot powder was weighed and dissolved in 20 mL of methanol; 23 g of ZnSO4·7H2O powder was weighed and dissolved in 40 mL of deionized water. The methanol dispersion of carbon quantum dots was added to zinc acetate solution and sonicated for 1 h. After standing for 1 day, the solution was filtered to obtain a clear electrolyte.

[0067] Battery assembly and results:

[0068] A zinc-ion symmetric battery was assembled using commercially available zinc sheets and the electrolyte according to the steps in Example 1, at 2 mA / cm². 2 At the current density, the zinc surface after battery cycling exhibits a preferred orientation of (002) planes. The zinc surface morphology is shown in [reference needed]. Figure 2 .

[0069] Example 6

[0070] The synthesis steps of carbon quantum dots are as shown in Example 1.

[0071] Electrolyte preparation scheme:

[0072] Weigh 150 mg of synthesized carbon quantum dot powder and dissolve it in 15 mL of acetonitrile; weigh 11.5 g of ZnSO4·7H2O powder and dissolve it in 20 mL of deionized water. Add the acetonitrile dispersion of carbon quantum dots to zinc sulfate solution, sonicate for 1 h, let stand for 1 day, and then filter to obtain a clear electrolyte.

[0073] Battery assembly and results:

[0074] A zinc-ion symmetric battery was assembled using zinc-aluminum alloy sheets and the electrolyte according to the steps in Example 1, at a speed of 10 mA / cm². 2 At the current density, the zinc surface after battery cycling exhibits a preferred orientation of (002) planes. The zinc surface morphology is shown in [reference needed]. Figure 2 .

[0075] Example 7

[0076] The synthesis steps of carbon quantum dots are as shown in Example 1.

[0077] Electrolyte preparation scheme:

[0078] Weigh 100 mg of synthesized carbon quantum dot powder and dissolve it in 20 mL of acetone; weigh 8.1 g of ZnCl2 powder and dissolve it in 20 mL of deionized water. Add the acetone dispersion of carbon quantum dots to a zinc chloride solution and sonicate for 1 hour. After standing for 1 day, filter to obtain a clear electrolyte.

[0079] Battery assembly and results:

[0080] A zinc-ion symmetric battery was assembled using zinc-copper alloy sheets and the electrolyte according to the steps of Example 1, at 0.5 mA / cm². 2 At the current density, the zinc surface after battery cycling exhibits a preferred orientation of (002) planes. The zinc surface morphology is shown in [reference needed]. Figure 2 .

[0081] Example 8

[0082] The synthesis steps of carbon quantum dots are as shown in Example 1.

[0083] Electrolyte preparation scheme:

[0084] Weigh 30 mg of synthesized carbon quantum dot powder and dissolve it in 1 mL of benzyl alcohol; weigh 10.8 g of ZnCl2 powder and dissolve it in 40 mL of deionized water. Add the benzyl alcohol dispersion of carbon quantum dots to zinc chloride solution, sonicate for 1 h, let stand for 1 day, and then filter to obtain a clear electrolyte.

[0085] Battery assembly and results:

[0086] A zinc-ion symmetric battery was assembled using a zinc-copper alloy sheet and the electrolyte according to the steps in Example 1, at a speed of 2 mA / cm². 2 At the current density, the zinc surface after battery cycling exhibits a preferred orientation of (002) planes. The zinc surface morphology is shown in [reference needed]. Figure 2 .

[0087] Comparative Example 1

[0088] 115.0 g of ZnSO4·7H2O powder was weighed and dissolved in an appropriate amount of ultrapure water to prepare a 2M ZnSO4 solution. A zinc-ion symmetric cell was assembled using commercially available zinc foil and the 2M ZnSO4 solution according to the steps in Example 1. The cell was then connected to an electrochemical charge-discharge apparatus and set to 0.5 mA / cm². 2 The cycling current density and 1-hour charge-discharge cycle were measured. After 80 hours of cycling, the battery failed due to trigger voltage protection circuit breaker failure. The zinc foil surface showed obvious dendrites after cycling; surface morphology images are shown below. Figure 5 The recycled zinc foil contained a high amount of byproducts, and the zinc crystal orientation was consistent with the (101) orientation of the initial zinc foil. The X-ray diffraction (XRD) pattern of the recycled zinc foil is shown below. Figure 6 Comparative Example 2

[0089] Weigh 54.5 g of ZnCl2 powder and dissolve it in an appropriate amount of ultrapure water to prepare a 2 M ZnCl2 solution. Using commercially available zinc foil and the 2 M ZnCl2 solution, assemble a zinc-ion symmetric cell according to the steps in Example 1, connect it to an electrochemical charge-discharge apparatus, and set it to 0.5 mA / cm². 2 The cycling current density and charge-discharge cycle of 15 min were measured. After 40 h of cycling, the battery failed due to the trigger voltage protection circuit breaking. The zinc foil after cycling exhibited a dendritic morphology and (101) plane orientation similar to Comparative Example 1.

[0090] Comparative Example 3

[0091] Synthesis of hydrophilic carbon quantum dots:

[0092] 9g of citric acid powder was dissolved in 3mL of ethylenediamine in 30mL of deionized water, stirred for 30min, transferred to a reaction vessel, and heated in an oven at 180℃ for 5h. After cooling to room temperature, the mixture was freeze-dried to obtain hydrophilic carbon quantum dot powder.

[0093] Electrolyte preparation:

[0094] 11.5 g of ZnSO4·7H2O powder was dissolved in 20 mL of deionized water to obtain a 2 M zinc sulfate solution. 20 mg of synthesized hydrophilic quantum dots were directly added to the electrolyte and dissolved to obtain a clear hydrophilic quantum dot-controlled zinc sulfate electrolyte.

[0095] Battery assembly and results:

[0096] A zinc-ion symmetric battery was assembled using zinc foil and the electrolyte according to the steps of Example 1, at 2 mA / cm². 2 After 100 hours of short-circuiting at a current density, the zinc surface of the battery exhibited a preferred orientation of the (101) plane and contained numerous surface byproducts. XRD results are shown in [Figure number missing]. Figure 8 Zinc surface morphology is shown in [reference needed]. Figure 7 .

[0097] Comparative Example 4

[0098] The synthesis of hydrophilic quantum dots is shown in Comparative Example 3.

[0099] Electrolyte preparation:

[0100] 5.4 g of ZnCl2 powder was dissolved in 20 mL of deionized water to obtain a 2 M zinc chloride solution. 20 mg of synthesized hydrophilic quantum dots were directly added to the electrolyte and dissolved to obtain a clear hydrophilic quantum dot-controlled zinc chloride electrolyte.

[0101] Battery assembly and results:

[0102] A zinc-ion symmetric battery was assembled using zinc foil and the electrolyte according to the steps of Example 1, at 2 mA / cm². 2 The zinc foil was short-circuited for 50 hours under a current density. After cycling, the zinc foil exhibited a dendritic morphology and (101) plane orientation similar to Comparative Example 3.

Claims

1. An electrolyte containing carbon quantum dots that protects the zinc negative electrode in a zinc-ion battery, characterized in that: Hydrophobic carbon quantum dots are used as additives in the electrolyte, the solvent of the electrolyte is a mixture of water and an organic solvent, and the solute is a zinc salt; the organic solvent is one or more of methanol, ethanol, isopropanol, acetone, and dimethylformamide; The volume ratio of the organic solvent to water is greater than 0 and less than or equal to 1. The concentration of carbon quantum dots is 0–50 mg / mL, and is not 0; Hydrophobic carbon quantum dots have a size of less than 5 nm; The preparation method of hydrophobic carbon quantum dots includes the following steps: 1) Use a small molecule organic solvent A, wherein A is one or more of acetone and butanone; 2) The strong alkali powder B(OH) added to 1) a Where B is one or more of Li, Na, Ka, Ca, and Sr, and a = 1 to 2; small molecule organic solvents react with strong base powder B(OH). a The dosage ratio is 10-100 mL : 1-40 g; 3) Stir the solid-liquid mixture obtained in step 2) at a speed of 100-1500 rpm for 10-200 min, and let it stand for 1-50 days; 4) Neutralize the product obtained in step 3) with 0.1-10M hydrochloric acid or sulfuric acid to pH=7; 5) Separate the carbon quantum dot enriched phase from the product obtained in step 4) and wash it with deionized water 2 to 20 times; 6) The product obtained in step 5) is dried under vacuum at 60-200℃ for 12-48 hours.

2. The electrolyte according to claim 1, characterized in that: The zinc salt of the solute has the structural formula ZnX a Where X is Cl - SO4 2- NO3 - CH3COO - CF3SO3 - ClO4 - One or more of the following, where a = 1~2; the zinc salt ZnX a The concentration is 0.1~5 M.

3. The method for preparing the electrolyte as described in claim 1, characterized in that: Includes the following steps: (1) Hydrophobic carbon quantum dot powder is dissolved in a certain amount of organic solvent, wherein the organic solvent is one or more of methanol, ethanol, isopropanol, acetone, and dimethylformamide, and the concentration of carbon quantum dots is 0~50 mg / mL and is not 0; (2) Add a certain amount of zinc salt ZnX a Dissolves in an aqueous solution, where X is Cl. - SO4 2- NO3 - CH3COO - CF3SO3 - ClO4 - One or more of the following, where a = 1~2; the zinc salt ZnX a Concentrations range from 0.1 to 6 M; (3) Add the organic dispersion of carbon quantum dots from step (1) to the electrolyte from step (2), stir until a clear liquid is formed, and sonicate for 10 to 500 min; (4) Let the liquid obtained in step (3) stand for 0 to 5 days, and the liquid temperature is not zero, and then filter it to obtain a clear electrolyte.

4. A zinc-ion battery, characterized in that: The electrolyte contains the electrolyte according to any one of claims 1-2, and uses a zinc-based material as the zinc negative electrode active material.

5. The zinc-ion battery according to claim 4, characterized in that: The zinc negative electrode is zinc sheet, zinc powder, porous zinc, or zinc alloy.

6. The zinc-ion battery according to claim 4, characterized in that: The zinc negative electrode is zinc foil or zinc mesh.

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