Aqueous zinc ion battery electrolyte and preparation method and application thereof

Abstract

The invention relates to the technical field of aqueous zinc ion batteries, in particular to an aqueous zinc ion battery electrolyte as well as a preparation method and application thereof. The invention provides an aqueous zinc ion battery electrolyte. The aqueous zinc ion battery electrolyte comprises soluble zinc salt and fulvic acid, and the concentration of the fulvic acid in the electrolyte is 0.01-50 g / L; wherein rich oxygen-containing functional groups contained in fulvic acid molecules can serve as strong coordination sites to be combined with Zn < 2 + > to generate coordination, so that the migration rate of zinc ions is effectively reduced, and uniform deposition of the zinc ions on the surface of the negative electrode is promoted; meanwhile, direct contact between water molecules and the zinc negative electrode can be reduced by utilizing a molecular interface layer formed by fulvic acid molecules on the surface of the zinc negative electrode, so that water-induced side reaction can be relieved. And the cycle stability of the battery is improved through the effects. In addition, the fulvic acid is wide in source, low in cost and environment-friendly, the production cost of the water-based zinc ion battery is reduced, and large-scale application of the water-based zinc ion battery is promoted.

Description

Technical Field

[0001] This application relates to the field of aqueous zinc-ion battery technology, specifically to an aqueous zinc-ion battery electrolyte, its preparation method, and its application. Background Technology

[0002] While lithium-ion batteries are widely used in portable electronic devices and new energy fields due to their high energy density, their development is facing key challenges such as the increasing consumption of lithium resources, rising costs, and the flammability and toxicity of organic electrolytes, which limit their application in large-scale energy storage. Therefore, aqueous multivalent metal-ion batteries (such as calcium, zinc, and magnesium-ion batteries) have attracted attention due to their advantages such as safety. Among them, aqueous zinc-ion batteries (AZIBs) have become a highly promising candidate system for large-scale energy storage due to their abundant zinc resources, low cost, high safety, and environmental friendliness.

[0003] In the core components of aqueous zinc-ion batteries, the zinc anode plays a crucial role. Its advantages lie not only in high capacity and low potential, but also in its high hydrogen evolution overpotential, which helps broaden the battery's electrochemical stability window and provides a foundation for achieving higher energy densities. However, problems commonly encountered with zinc anodes during cycling, such as uncontrollable dendrite growth, hydrogen evolution side reactions, and interface passivation, severely restrict the battery's cycle life and energy efficiency. Electrolyte modification, as a simple and efficient strategy, has been widely applied in the research of suppressing and optimizing side reactions in zinc-ion batteries. Therefore, there is an urgent need to construct novel aqueous electrolyte systems: on the one hand, they must ensure excellent electrochemical stability; on the other hand, they must effectively reduce the activity of side reactions during battery cycling, ultimately solving the core problem of short lifespan in aqueous zinc-ion batteries at its root. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of the prior art by providing an aqueous zinc-ion battery electrolyte, its preparation method, and its application, thereby solving the problem of short cycle life in existing aqueous zinc-ion batteries.

[0005] In one aspect, this application provides an aqueous zinc-ion battery electrolyte, comprising a soluble zinc salt and fulvic acid, wherein the concentration of fulvic acid in the electrolyte is 0.01-50 g / L.

[0006] As an example, the concentration of fulvic acid in the electrolyte may be 0.01 g / L, 0.5 g / L, 1 g / L, 3 g / L, 5 g / L, 7 g / L, 9 g / L, 11 g / L, 13 g / L, 15 g / L, 17 g / L, 19 g / L, 21 g / L, 23 g / L, 25 g / L, 27 g / L, 29 g / L, 31 g / L, 33 g / L, 35 g / L, 37 g / L, 39 g / L, 41 g / L, 43 g / L, 45 g / L, 47 g / L, 49 g / L, 50 g / L, or within any range of the above values.

[0007] It should be noted that the fulvic acid provided in this application contains abundant oxygen-containing functional groups (oxygen content typically reaches 45%-55%), and these functional groups can serve as strong coordination sites with Zn. 2+ By binding and replacing water molecules in its solvation shell, Zn significantly decreases. 2+ The desolvation energy barrier promotes the desolvation process. During this process, the content of free water molecules in the system decreases accordingly, and the reduction of free water can effectively inhibit the occurrence and progress of hydrogen evolution corrosion reaction on the zinc electrode surface.

[0008] In one alternative embodiment, the soluble zinc salt includes at least one of zinc sulfate, zinc perchlorate, zinc chloride, and zinc trifluoromethanesulfonate.

[0009] In one alternative embodiment, the concentration of the soluble zinc salt in the electrolyte is 1-3 mol / L; as an example, the concentration of the soluble zinc salt in the electrolyte can be 1 mol / L, 1.2 mol / L, 1.4 mol / L, 1.6 mol / L, 1.8 mol / L, 2 mol / L, 2.2 mol / L, 2.4 mol / L, 2.6 mol / L, 2.8 mol / L, 3 mol / L, or within any of the above values.

[0010] Secondly, this application provides a method for preparing the above-mentioned aqueous zinc-ion battery electrolyte, comprising the following steps: dissolving a soluble zinc salt in a solvent, adding fulvic acid, mixing, and obtaining the aqueous zinc-ion battery electrolyte.

[0011] In one alternative embodiment, the solvent comprises deionized water.

[0012] Thirdly, this application provides an aqueous zinc-ion battery, using the above-described aqueous zinc-ion battery electrolyte or the aqueous zinc-ion battery electrolyte prepared by the above-described preparation method.

[0013] In one alternative embodiment, the aqueous zinc-ion battery further includes a positive electrode, a separator, and a negative electrode.

[0014] In one alternative embodiment, the positive electrode includes I. - At least one of I2, MnO2, and V2O5; In one optional embodiment, the diaphragm comprises at least one of glass fiber, filter paper, single-layer polypropylene membrane, single-layer polyethylene membrane, Nafion membrane, PVDF membrane, polyester membrane, cellulose membrane, polyimide membrane, non-woven diaphragm, and inorganic composite membrane.

[0015] In one alternative embodiment, the negative electrode is at least one of zinc sheet, zinc foil, zinc plate, and zinc powder.

[0016] Fourthly, this application provides an electrical device including the aforementioned aqueous zinc-ion battery.

[0017] The technical solution of this application has the following advantages: 1. This application provides an aqueous zinc-ion battery electrolyte, which for the first time uses fulvic acid as an additive in the aqueous zinc-ion battery electrolyte; wherein, the fulvic acid molecule contains abundant oxygen-containing functional groups (oxygen content typically reaches 45%-55%), and these functional groups can serve as strong coordination sites with Zn. 2+ The combination of coordination effects effectively reduces the migration rate of zinc ions, promoting their uniform deposition on the negative electrode surface. Simultaneously, this application utilizes the adsorption tendency of fulvic acid molecules on the zinc negative electrode surface to form a molecular interface layer. This interface layer reduces direct contact between water molecules and the zinc negative electrode, thereby helping to mitigate water-induced side reactions. These synergistic effects significantly improve the cycle stability of the battery. Furthermore, fulvic acid has significant advantages in terms of wide availability, low cost, and environmental friendliness, which helps reduce the overall production cost of aqueous zinc-ion batteries, providing strong potential support for their large-scale application.

[0018] 2. The method for preparing an aqueous zinc-ion battery electrolyte provided in this application is simple, low-cost, suitable for large-scale industrial production, and has significant practical application value.

[0019] 3. The aqueous zinc-ion battery and electrical equipment provided in this application have the same advantages as the electrolytes mentioned above because they use the electrolyte provided in this application, and will not be described in detail here. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0021] Figure 1For the Zn / / I2 coin cell assembled using the electrolyte prepared in Example 1, at 30 mA / cm 2 Cyclic performance at current density. Detailed Implementation

[0022] The following embodiments are provided to better understand this application and are not limited to the preferred embodiments described herein. They do not constitute a limitation on the content and scope of protection of this application. Any product that is the same as or similar to this application, derived by anyone under the guidance of this application or by combining features of this application with other prior art, falls within the scope of protection of this application.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having” and any variations thereof in the text of this application are intended to cover non-exclusive inclusion.

[0024] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0025] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of the specific range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. In this application, unless otherwise stated, the numerical range "ab" represents a shortened representation of any combination of real numbers from a to b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have been listed herein, and "0-5" is merely a shortened representation of these numerical combinations. Furthermore, when a parameter is described as an integer ≥ 2, it is equivalent to disclosing that the parameter can be, for example, integers 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0026] In the description of the embodiments of this application, the term "and / or" is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone.

[0027] In the description of the embodiments of this application, the term "at least one" refers to one or more (including two).

[0028] Unless otherwise specified, all steps in this application may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the mention that the method may also include step (c) indicates that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0029] For experiments not specifically described in the examples, the procedures or conditions should be followed according to the conventional experimental procedures described in the literature in this field. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products.

[0030] Example 1 This embodiment provides an aqueous zinc-ion battery electrolyte, the specific composition and preparation method of which are as follows: Zinc sulfate is dissolved in deionized water, fulvic acid is added, and the mixture is prepared to obtain the aqueous zinc-ion battery electrolyte. The concentration of zinc sulfate is 2 mol / L, and the mass concentration of fulvic acid is 15 g / L.

[0031] Figure 1 For the Zn-I2 coin cell assembled using the electrolyte prepared in Example 1, at 30 mA / cm 2 Cyclic performance at current density.

[0032] Example 2 This embodiment provides an aqueous zinc-ion battery electrolyte, the specific composition and preparation method of which are as follows: Zinc sulfate was dissolved in deionized water, fulvic acid was added, and the mixture was prepared to obtain the aqueous zinc-ion battery electrolyte. The concentration of zinc sulfate was 2 mol / L, and the mass concentration of fulvic acid was 30 g / L.

[0033] Example 3 This embodiment provides an aqueous zinc-ion battery electrolyte, the specific composition and preparation method of which are as follows: Zinc sulfate is dissolved in deionized water, fulvic acid is added, and the mixture is prepared to obtain the aqueous zinc-ion battery electrolyte. The concentration of zinc sulfate is 1 mol / L, and the mass concentration of fulvic acid is 50 g / L.

[0034] Example 4 This embodiment provides an aqueous zinc-ion battery electrolyte, the specific composition and preparation method of which are as follows: Zinc sulfate was dissolved in deionized water, fulvic acid was added, and the mixture was prepared to obtain the aqueous zinc-ion battery electrolyte. The concentration of zinc sulfate was 3 mol / L, and the mass concentration of fulvic acid was 5 g / L.

[0035] Example 5 This embodiment provides an aqueous zinc-ion battery electrolyte, the specific composition and preparation method of which are as follows: Zinc perchlorate was dissolved in deionized water, fulvic acid was added, and the mixture was prepared to obtain the aqueous zinc-ion battery electrolyte. The concentration of zinc perchlorate was 2 mol / L, and the mass concentration of fulvic acid was 15 g / L.

[0036] Example 6 This embodiment provides an aqueous zinc-ion battery electrolyte, the specific composition and preparation method of which are as follows: Zinc chloride was dissolved in deionized water, fulvic acid was added, and the mixture was prepared to obtain the aqueous zinc-ion battery electrolyte. The concentration of zinc chloride was 2 mol / L, and the mass concentration of fulvic acid was 15 g / L.

[0037] Example 7 This embodiment provides an aqueous zinc-ion battery electrolyte, the specific composition and preparation method of which are as follows: Zinc trifluoromethanesulfonate was dissolved in deionized water, and fulvic acid was added and mixed to obtain the aqueous zinc-ion battery electrolyte. The concentration of zinc trifluoromethanesulfonate was 2 mol / L, and the mass concentration of fulvic acid was 15 g / L.

[0038] Comparative Example 1 This comparative example provides an aqueous zinc-ion battery electrolyte, the specific composition and preparation method of which are as follows: The only difference between this comparative example and Example 4 is that fulvic acid was not added.

[0039] Comparative Example 2 This comparative example provides an aqueous zinc-ion battery electrolyte, the specific composition and preparation method of which are as follows: The only difference between this comparative example and Example 4 is that fulvic acid is replaced with malic acid of equal mass concentration.

[0040] Comparative Example 3 This comparative example provides an aqueous zinc-ion battery electrolyte, the specific composition and preparation method of which are as follows: The only difference between this comparative example and Example 4 is that fulvic acid is replaced with chloramphenicol of equal mass concentration.

[0041] Comparative Example 4 This comparative example provides an aqueous zinc-ion battery electrolyte, the specific composition and preparation method of which are as follows: The only difference between this comparative example and Example 4 is that the mass concentration of fulvic acid is 60 g / L.

[0042] Test case The aqueous zinc-ion battery electrolytes provided in the various embodiments and comparative examples were applied to aqueous zinc-ion batteries, and then their electrical performance was tested.

[0043] The preparation method of the aqueous zinc-ion battery includes the following steps: Polyaniline, activated carbon, and polyvinylidene fluoride (PVDF) were mixed and ground in a mass ratio of 7:2:1, and then coated onto carbon cloth. The coated carbon cloth was then immersed in a 0.5 mol / L ZnI₂ solution for 12 hours, and finally dried in a vacuum oven at 80°C for 24 hours to obtain a product containing I₂. - The electrode sheet is used; the battery case uses a CR2032 type button cell, with the cut electrode sheet as the positive electrode, the aqueous zinc-ion battery electrolyte provided in the examples and comparative examples as the electrolyte, glass fiber as the separator, and 100μm thick zinc foil as the negative electrode to assemble a button cell.

[0044] Charge and discharge test: The assembled coin cell was subjected to an A / cm test at 30 mA / cm. 2 Constant current charge-discharge tests were conducted at a current density of 0.4V-1.6V, with capacity decay to 0.1mAh / cm³. 2 This is the cutoff condition.

[0045] The specific test results are shown in the table below: Table 1 Test Results

[0046] Based on comparative analysis of experimental data, the Zn-I2 batteries assembled using fulvic acid as an electrolyte additive in Examples 1-7 of this application showed significantly improved cycle life compared to the Zn-I2 batteries assembled using other additives as electrolyte additives but without fulvic acid in Comparative Examples 1-3. Furthermore, as shown in Comparative Example 4, optimizing the mass concentration of fulvic acid in the electrolyte can also significantly extend the product's lifespan.

[0047] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. An aqueous zinc-ion battery electrolyte, characterized in that, It includes soluble zinc salts and fulvic acid, wherein the concentration of fulvic acid in the electrolyte is 0.01-50 g / L.

2. The aqueous zinc-ion battery electrolyte according to claim 1, characterized in that, The soluble zinc salt includes at least one of zinc sulfate, zinc perchlorate, zinc chloride, and zinc trifluoromethanesulfonate.

3. The aqueous zinc-ion battery electrolyte according to claim 1 or 2, characterized in that, The concentration of the soluble zinc salt in the electrolyte is 1-3 mol / L.

4. A method for preparing the aqueous zinc-ion battery electrolyte according to any one of claims 1-3, characterized in that, Includes the following steps: Soluble zinc salts are dissolved in a solvent, fulvic acid is added, and the mixture is prepared to obtain the aqueous zinc-ion battery electrolyte.

5. The method for preparing the aqueous zinc-ion battery electrolyte according to claim 4, characterized in that, The solvent includes deionized water.

6. An aqueous zinc-ion battery, characterized in that, Includes the aqueous zinc-ion battery electrolyte according to any one of claims 1-3 or the aqueous zinc-ion battery electrolyte prepared by the preparation method according to any one of claims 4-5.

7. The aqueous zinc-ion battery according to claim 6, characterized in that, The aqueous zinc-ion battery also includes a positive electrode, a separator, and a negative electrode.

8. The aqueous zinc-ion battery according to claim 7, characterized in that, The positive electrode includes I - At least one of I2, MnO2, and V2O5; And / or, the diaphragm includes at least one of glass fiber, filter paper, single-layer polypropylene membrane, single-layer polyethylene membrane, Nafion membrane, PVDF membrane, polyester membrane, cellulose membrane, polyimide membrane, non-woven diaphragm, and inorganic composite membrane.

9. The aqueous zinc-ion battery according to claim 7, characterized in that, The negative electrode is at least one of zinc sheet, zinc foil, zinc plate, and zinc powder.

10. An electrical appliance, characterized in that, Including the aqueous zinc-ion battery as described in any one of claims 6-9.

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