A high-voltage electrolyte for a bifunctional aqueous zinc-ion battery, a preparation method therefor and applications thereof

Abstract

This invention discloses a dual-functional aqueous zinc-ion battery high-voltage electrolyte, its preparation method, and its application, belonging to the field of aqueous zinc-ion battery technology. The invention uses additives with the general structural formula R consisting of hydroxyl, carboxyl, acetyl, and methoxy groups to prepare the electrolyte. These additives contain oxygen-containing functional groups that can act as hydrogen bond acceptors, significantly improving the aqueous solubility of the molecules. Furthermore, they can regulate the electrolyte ion concentration through specific interactions with solvent molecules, thereby controlling the solvation sheath structure of zinc ions by reducing the number of solvent molecules. Simultaneously, these functional groups containing oxygen atoms as hydrogen bond acceptors are strong electron-withdrawing groups, capable of interacting with water molecules to form intermolecular hydrogen bonds. The oxygen atom acts as an electron donor, and the hydrogen atoms in water act as proton donors, disrupting the original hydrogen bonds and tetrahedral structure of water molecules. By blocking the formation of the hydrogen bond network of water molecules, this effectively inhibits water-induced corrosion side reactions and hydrogen evolution behavior.

Description

Technical Field

[0001] This invention belongs to the field of aqueous zinc-ion battery technology, and particularly relates to a dual-functional aqueous zinc-ion battery high-voltage electrolyte, its preparation method and application. Background Technology

[0002] Traditional lithium-ion batteries suffer from high prices, safety concerns, and limited lithium resources. Therefore, developing low-cost, environmentally friendly, and safe large-scale energy storage technologies is crucial. Aqueous zinc-ion batteries (AZIBs), employing zinc anodes and aqueous electrolytes, have emerged as promising candidates for grid-scale energy storage. The zinc anode boasts a high theoretical specific capacity (820 mAh·g). -1 It features a moderate operating potential (-0.76V vs SHE) and inherent safety. However, a non-uniform electric field often leads to disordered Zn... 2+ Deposition leads to the rapid formation of dendrites. Simultaneously, the adsorption of H2O molecules on the Zn anode triggers unfavorable side reactions, including hydrogen evolution reaction (HER) and corrosion, which degrade the stability of the Zn anode and hinder the practical application of aqueous zinc-ion batteries. On the one hand, Zn... 2+ In aqueous solution, it forms a stable solvation sheath with surrounding H2O molecules, leading to the formation of a solvation sheath in Zn. 2+ During nucleation, an unavoidable HER occurs on the Zn anode surface, and the generation of excess H2 affects the OH groups around the electrode. - The concentration of Zn leads to the formation of byproducts such as Zn4SO4(OH)6·xH2O on the electrode surface, which in turn hinders the formation of Zn on the Zn negative electrode surface. 2+ The reversibility of H2 generation ultimately leads to a decrease in the battery's coulombic efficiency (CE). Furthermore, H2 generation can damage the sealed battery structure to some extent, affecting the battery assembly and posing potential safety risks. More seriously, the growth of zinc dendrites reduces the reversibility of the zinc anode; excessively long dendrites break off and become dead zinc, damaging the battery. These problems have severely limited the application of AZIBs.

[0003] To address the aforementioned problems of aqueous zinc-ion batteries, researchers have conducted in-depth studies in several areas, including surface modification of the zinc anode, development of high-concentration electrolytes, and application of electrolyte additives. Among these, introducing additives into the electrolyte is considered a simple and efficient method. Electrolyte additives can significantly optimize the interfacial characteristics between the electrode and the electrolyte, thereby effectively mitigating problems such as dendrite growth, hydrogen evolution corrosion, and side reactions at the zinc anode, ultimately improving the overall performance and stability of the battery. Currently, commonly used electrolyte additives are mainly divided into organic additives containing functional small molecules and inorganic additives. Additives containing functional molecules adsorb onto the zinc anode surface, regulating the deposition behavior of zinc ions and forming an SEI film in situ on the zinc surface, isolating active water and inhibiting dendrite growth and corrosion. Inorganic additives, on the other hand, can form a positively charged electrostatic shielding layer on the zinc anode surface, effectively inhibiting the growth of zinc dendrites through electrostatic repulsion and inducing Zn... 2+ Uniform deposition reduces desolvation energy.

[0004] Despite significant progress in electrolyte additive research, most studies have focused on the influence of a single polar functional group in the additive on the zinc anode, neglecting the synergistic regulatory effects of multiple functional groups. Therefore, understanding the correlation between the synergistic regulation of multiple functional groups in additive molecules within the electrolyte system and the electrochemical performance of the zinc anode is crucial for achieving high-performance aqueous zinc-ion batteries. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention proposes a dual-functional aqueous high-voltage electrolyte for zinc-ion batteries, its preparation method, and its application. This invention, through the synergistic regulation of multiple functional groups, protects the zinc anode and inhibits the growth of zinc dendrites, thereby effectively improving the stability of aqueous zinc-ion batteries.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] This invention provides a dual-functional aqueous zinc-ion battery high-voltage electrolyte, comprising the following components: additives, soluble zinc salts, and water;

[0008] The general structural formula of the additive is: R is selected from hydroxyl (-OH), carboxyl (-COOH), acetyl (-COCH3), or methoxy (-OCH3).

[0009] Specifically, the additive is selected from at least one of 4-hydroxybenzenesulfonamide (4-BD), 4-carboxybenzenesulfonamide (4-CD), 4-acetylbenzenesulfonamide (4-ND), and 4-methoxybenzenesulfonamide (4-OD).

[0010] Furthermore, the soluble zinc salt is selected from at least one of zinc sulfate, zinc trifluoromethanesulfonate, zinc bis(trifluoromethanesulfonyl)imide, zinc acetate, zinc chloride, and zinc nitrate.

[0011] Furthermore, the concentration of soluble zinc salt in the high-voltage electrolyte of the bifunctional aqueous zinc-ion battery is 1–3 mol / L, and the concentration of additives is 0.001–0.02 mol / L.

[0012] Furthermore, the concentration of soluble zinc salt in the high-voltage electrolyte of the bifunctional aqueous zinc-ion battery is 1–2 mol / L, and the concentration of additives is 0.005–0.015 mol / L.

[0013] This invention provides a method for preparing a dual-functional aqueous zinc-ion battery high-voltage electrolyte as described in the above technical solution. Soluble zinc salt is dissolved in water to obtain a soluble zinc salt electrolyte; additives are added to the soluble zinc salt electrolyte, and the mixture is heated and stirred, then cooled to obtain the dual-functional aqueous zinc-ion battery high-voltage electrolyte.

[0014] Furthermore, the heating and stirring temperature is 50°C, the time is 12 hours, and the stirring speed is 500 r / min.

[0015] The present invention also provides an aqueous zinc-ion battery, comprising a negative electrode, a positive electrode, a separator, and an electrolyte; the electrolyte comprises the high-voltage electrolyte for a dual-functional aqueous zinc-ion battery described in the above technical solution.

[0016] Furthermore, the negative electrode is selected from at least one of zinc sheet, zinc foil, zinc powder, and zinc alloy;

[0017] The positive electrode is selected from zinc sheet, copper foil, or active material electrode film; the active material in the active material electrode film is selected from at least one of manganese-based compounds and vanadium-based compounds.

[0018] The diaphragm is selected from at least one of glass fiber membrane and nonwoven fabric.

[0019] Furthermore, the electrolyte also includes cations corresponding to the active materials in the active material electrode film.

[0020] Compared with the prior art, the present invention has the following advantages and technical effects:

[0021] 1. The present invention adopts the following general structural formula: Additives with R groups consisting of hydroxyl, carboxyl, acetyl, and methoxy groups are used to prepare electrolytes. These functional groups, containing oxygen atoms that can act as hydrogen bond acceptors, not only significantly improve the aqueous solubility of the molecules but also regulate the electrolyte ion concentration through specific interactions with solvent molecules, thereby controlling the solvation sheath structure of zinc ions by reducing the number of solvent molecules. Simultaneously, these functional groups containing oxygen atoms as hydrogen bond acceptors are strong electron-withdrawing groups that can interact with water molecules to form intermolecular hydrogen bonds. The oxygen atom acts as an electron donor, and the hydrogen atom in water acts as a proton donor, disrupting the original hydrogen bonds and tetrahedral structure of water molecules. By blocking the formation of the hydrogen bond network of water molecules, this effectively inhibits water-induced corrosion side reactions and hydrogen evolution behavior.

[0022] 2. The sulfonamide groups in the additive exhibit excellent adsorption properties for the zinc anode, preferentially adsorbing onto its surface. During battery cycling, they can induce the in-situ formation of a solid electrolyte interphase (SEI) film rich in zinc sulfide (ZnS). This SEI film effectively regulates zinc ion deposition during the discharge process of the zinc-ion battery, inhibiting zinc dendrite growth and the formation of dead zinc, thereby significantly improving the cycle stability and extending the cycle life of the aqueous zinc-ion battery. Simultaneously, the synergistic effect of the oxygen-containing functional groups in the additive, which act as hydrogen bond acceptors, with the sulfonamide groups, can construct a stable interface on the anode surface, blocking side reactions and further improving the cycle stability of the aqueous zinc-ion battery.

[0023] 3. The bifunctional aqueous zinc-ion battery high-voltage electrolyte provided by this invention has advantages such as low cost, low additive dosage, wide applicability, and easy large-scale preparation, showing broad application prospects and important research value in the field of new energy batteries. Attached Figure Description

[0024] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0025] Figure 1 The XRD patterns are of zinc foil after being immersed in the electrolytes prepared in Examples 1 to 4 and Comparative Example 1 for one week.

[0026] Figure 2 Zn / / Zn symmetric cells assembled using the electrolytes prepared in Example 1 and Comparative Example 1 were tested at current densities of 0.5, 1, 2, 5, 10, 15, and 20 mA / cm². 2 Specific capacity is 1mAh / cm³ 2 Constant current charge-discharge curves under test conditions;

[0027] Figure 3To test the Zn / / Zn symmetric cells assembled using the electrolytes prepared in Examples 1-4 and Comparative Example 1 at 1 mA / cm 2 1mAh / cm 2 Constant current charge-discharge curves under test conditions;

[0028] Figure 4 To test the Zn / / Cu battery assembled using the electrolytes prepared in Examples 1-4 and Comparative Example 1 at 4 mA / cm 2 1mAh / cm 2 Coulomb efficiency under test conditions;

[0029] Figure 5 To test the Zn / / Zn symmetric cells assembled using the electrolytes prepared in Example 1 and Comparative Example 1 at 1 mA / cm 2 1mAh / cm 2 SEM images of Zn foil after 100 cycles under the test conditions, where (a) is Comparative Example 1 and (b) is Example 1;

[0030] Figure 6 LSV curves of Zn / / Zn symmetric cells assembled using the electrolytes prepared in Example 1 and Comparative Example 1;

[0031] Figure 7 The rate performance of Zn / / MnO2 full cells assembled using the electrolytes prepared in Example 1 and Comparative Example 1 is shown in the figure.

[0032] Figure 8 The capacity-voltage curves of Zn / / MnO2 full cells assembled using the electrode solutions prepared in Example 1 and Comparative Example 1 at a current density of 0.5 A / g are shown.

[0033] Figure 9 To assess the long-cycle performance of Zn / / MnO2 full cells assembled using the electrolytes prepared in Example 1 and Comparative Example 1 at a current density of 5 A / g. Detailed Implementation

[0034] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0036] This invention provides a dual-functional aqueous zinc-ion battery high-voltage electrolyte, comprising the following components: additives, soluble zinc salts, and water;

[0037] The general structural formula of the additive is: Wherein, R is selected from hydroxyl, carboxyl, acetyl, or methoxy groups. This invention solves the problems of zinc anode dendrite growth, hydrogen evolution corrosion, and side reactions present in existing aqueous zinc-ion batteries by using additives containing sulfonamide groups and oxygen-containing functional groups to prepare an electrolyte for aqueous zinc-ion batteries.

[0038] In a preferred embodiment, the additive is selected from 4-hydroxybenzenesulfonamide. 4-Carboxybenzenesulfonamide 4-Acetylbenzenesulfonamide and 4-methoxybenzenesulfonamide At least one of them.

[0039] In a preferred embodiment, the soluble zinc salt is selected from at least one of zinc sulfate, zinc trifluoromethanesulfonate, zinc bis(trifluoromethanesulfonyl)imide, zinc acetate, zinc chloride, and zinc nitrate.

[0040] In a preferred embodiment, the concentration of soluble zinc salt in the high-voltage electrolyte of the bifunctional aqueous zinc-ion battery is 1–3 mol / L, more preferably 1–2 mol / L.

[0041] Furthermore, the concentration of the additive in the high-voltage electrolyte of the bifunctional aqueous zinc-ion battery is 0.001–0.02 mol / L, and more preferably 0.005–0.015 mol / L.

[0042] This invention provides a method for preparing a dual-functional aqueous zinc-ion battery high-voltage electrolyte as described in the above technical solution. Soluble zinc salt is dissolved in water to obtain a soluble zinc salt electrolyte; additives are added to the soluble zinc salt electrolyte, and the mixture is heated and stirred, then cooled to obtain the dual-functional aqueous zinc-ion battery high-voltage electrolyte.

[0043] In a preferred embodiment, the heating and stirring temperature is 50°C, the time is 12 hours, and the stirring speed is 500 r / min.

[0044] The present invention also provides an aqueous zinc-ion battery, comprising a negative electrode, a positive electrode, a separator, and an electrolyte; the electrolyte comprises the high-voltage electrolyte for a dual-functional aqueous zinc-ion battery described in the above technical solution.

[0045] In a preferred embodiment, the negative electrode is selected from at least one of zinc sheet, zinc foil, zinc powder, and zinc alloy.

[0046] In a preferred embodiment, the positive electrode is selected from zinc sheet, copper foil, or active material electrode film.

[0047] In a preferred embodiment, the active material in the active material electrode film is selected from at least one of manganese-based compounds and vanadium-based compounds; the manganese-based compound is selected from MnO2; and the vanadium-based compound is selected from V2O5 or VO2.

[0048] In a preferred embodiment, the diaphragm is selected from at least one of glass fiber membrane and nonwoven fabric.

[0049] In a preferred embodiment, the electrolyte further includes cations corresponding to the active material in the active material electrode film. For example, when the active material in the active material electrode film is a manganese-based compound, the electrolyte also includes Mn. 2+ This is to inhibit manganese dissolution and improve the cycle stability of the positive electrode.

[0050] In this embodiment of the invention, room temperature refers to "25±2℃".

[0051] Unless otherwise specified, all raw materials used in the embodiments of this invention were purchased through commercial channels.

[0052] Example 1

[0053] A bifunctional aqueous high-voltage electrolyte for zinc-ion batteries is composed of 4-hydroxybenzenesulfonamide, zinc sulfate, and deionized water; the concentration of 4-hydroxybenzenesulfonamide in the bifunctional aqueous high-voltage electrolyte for zinc-ion batteries is 0.01 mol / L, and the concentration of zinc sulfate is 2 mol / L.

[0054] The specific steps for preparing the above-mentioned dual-functional aqueous zinc-ion battery high-voltage electrolyte are as follows:

[0055] S1. Dissolve 20 mmol ZnSO4·7H2O in deionized water and prepare 10 mL of 2 mol / L zinc sulfate electrolyte using a volumetric flask.

[0056] S2. Add 0.1 mmol of 4-hydroxybenzenesulfonamide to 10 mL of the above 2 mol / L zinc sulfate electrolyte, heat to 50 °C, maintain this temperature and stir at a stirring speed of 500 r / min for 12 h to dissolve the 4-hydroxybenzenesulfonamide. After cooling to room temperature, a homogeneous and transparent solution is obtained, which is the high-voltage electrolyte for bifunctional aqueous zinc-ion batteries.

[0057] Example 2

[0058] A dual-functional aqueous high-voltage electrolyte for zinc-ion batteries differs from Example 1 in that 4-hydroxybenzenesulfonamide is replaced with an equimolar amount of 4-carboxybenzenesulfonamide, while the rest is the same as in Example 1.

[0059] Example 3

[0060] A dual-functional aqueous high-voltage electrolyte for zinc-ion batteries differs from Example 1 in that 4-hydroxybenzenesulfonamide is replaced with an equimolar amount of 4-acetylbenzenesulfonamide, while the rest is the same as in Example 1.

[0061] Example 4

[0062] A dual-functional aqueous high-voltage electrolyte for zinc-ion batteries differs from Example 1 in that 4-hydroxybenzenesulfonamide is replaced with an equimolar amount of 4-methoxybenzenesulfonamide, while the rest is the same as in Example 1.

[0063] Example 5

[0064] A bifunctional aqueous high-voltage electrolyte for zinc-ion batteries is composed of 4-hydroxybenzenesulfonamide, zinc sulfate, and deionized water; the concentration of 4-hydroxybenzenesulfonamide in the bifunctional aqueous high-voltage electrolyte for zinc-ion batteries is 0.005 mol / L, and the concentration of zinc sulfate is 2 mol / L.

[0065] The specific steps for preparing the above-mentioned dual-functional aqueous zinc-ion battery high-voltage electrolyte are as follows:

[0066] (1) Dissolve 20 mmol ZnSO4·7H2O in deionized water and prepare 10 mL of 2 mol / L zinc sulfate electrolyte using a volumetric flask;

[0067] (2) Add 0.05 mmol of 4-hydroxybenzenesulfonamide to the above 10 mL of 2 mol / L zinc sulfate electrolyte, heat to 50 °C, maintain the temperature and stir at a stirring speed of 500 r / min for 12 h to dissolve the 4-hydroxybenzenesulfonamide, and cool to room temperature to obtain a homogeneous and transparent solution, which is the high voltage electrolyte of the bifunctional aqueous zinc-ion battery.

[0068] Example 6

[0069] A bifunctional aqueous high-voltage electrolyte for zinc-ion batteries is composed of 4-hydroxybenzenesulfonamide, zinc sulfate, and deionized water; the concentration of 4-hydroxybenzenesulfonamide in the bifunctional aqueous high-voltage electrolyte for zinc-ion batteries is 0.015 mol / L, and the concentration of zinc sulfate is 2 mol / L.

[0070] The specific steps for preparing the above-mentioned dual-functional aqueous zinc-ion battery high-voltage electrolyte are as follows:

[0071] (1) Dissolve 20 mmol ZnSO4·7H2O in deionized water and prepare 10 mL of 2 mol / L zinc sulfate electrolyte using a volumetric flask;

[0072] (2) Add 0.15 mmol of 4-hydroxybenzenesulfonamide to the above 10 mL of 2 mol / L zinc sulfate electrolyte, heat to 50 °C, maintain the temperature and stir at a stirring speed of 500 r / min for 12 h to dissolve the 4-hydroxybenzenesulfonamide, and cool to room temperature to obtain a homogeneous and transparent solution, which is the high voltage electrolyte of the bifunctional aqueous zinc-ion battery.

[0073] Comparative Example 1

[0074] A method for preparing a zinc sulfate electrolyte comprises the following steps: dissolving 20 mmol ZnSO4·7H2O in deionized water and preparing 10 mL of 2 mol / L zinc sulfate electrolyte using a volumetric flask.

[0075] Comparative Example 2

[0076] A method for preparing a zinc trifluoromethanesulfonate electrolyte comprises the following steps: dissolving 20 mmol Zn(OTF)2 in deionized water and preparing 10 mL of 2 mol / L zinc trifluoromethanesulfonate electrolyte using a volumetric flask.

[0077] Comparative Example 3

[0078] An aqueous zinc-ion battery electrolyte differs from Example 1 in that 4-hydroxybenzenesulfonamide is replaced with an equimolar amount of p-aminobenzenesulfonamide, otherwise it is the same as Example 1.

[0079] Application Example 1

[0080] A method for preparing a Zn / / Cu battery, the specific steps of which are as follows:

[0081] (1) Preparation of negative electrode sheet: A zinc foil of 100mm×100mm×0.3mm was polished with sandpaper, and the polished zinc foil was cut to obtain a zinc foil with a specification of 10mm×10mm×0.3mm.

[0082] (2) Preparation of positive electrode sheet: A copper foil of 100mm×100mm×0.02mm was polished with sandpaper, and the polished copper foil was cut to obtain a copper foil with a specification of 10mm×10mm×0.02mm.

[0083] (3) Assembly of Zn / / Cu battery: Commercial CR2032 electrode shells were used as positive and negative electrode shells respectively. Glass fiber (16mm in diameter) separator was used. 80μL of electrolyte was added. The battery was assembled in the order of negative electrode shell - negative electrode sheet - separator - positive electrode sheet - stainless steel sheet - spring sheet - positive electrode shell. After assembly, it was pressurized and sealed to obtain Zn / / Cu symmetric battery.

[0084] Application Example 2

[0085] A method for preparing a Zn / / Zn battery, comprising the following steps:

[0086] (1) Preparation of positive / negative electrode sheets: A 100mm×100mm×0.3mm zinc foil is polished with sandpaper, and the polished zinc foil is cut to obtain a zinc foil with a specification of 10mm×10mm×0.3mm.

[0087] (2) Assembly of Zn / / Zn symmetric cells: Using commercial CR2032 type electrode shells and glass fiber (16mm in diameter) separators, 80μL of electrolyte was added. The cells were assembled in the following order: negative electrode shell - negative electrode sheet - separator - positive electrode sheet - stainless steel sheet - spring sheet - positive electrode shell. After assembly, the cells were pressurized and sealed to obtain Zn / / Zn symmetric cells.

[0088] Application Example 3

[0089] A method for preparing a Zn / / MnO2 full cell, the specific steps of which are as follows:

[0090] (1) Preparation of the positive electrode: 0.507 g of manganese sulfate monohydrate (MnSO4·H2O) and 2 mL of 0.5 mol·L⁻¹ -1 Sulfuric acid (H₂SO₄) was dissolved in 90 mL of deionized water, and the solution was continuously stirred magnetically until it became completely clear. Then, 20 mL of 0.1 mol·L⁻¹ sulfuric acid was added. -1 Potassium permanganate (KMnO4) solution was added dropwise to the above solution under constant stirring. The mixture was stirred at room temperature for 2 hours, and then transferred to a PTFE-lined steel autoclave. The autoclave was then maintained at 120°C for 12 hours. After naturally cooling to room temperature, the precipitate was collected by centrifugation and repeatedly washed with deionized water to remove residual impurities. The obtained product was then dried in a vacuum oven at 60°C for 12 hours to obtain MnO2 powder. Subsequently, 10 mg of the above MnO2 powder, 10 mg of carbon nanotubes, and 0.2 mg of carbon nanotube alcohol dispersant were added to a centrifuge tube, followed by 30 mL of anhydrous ethanol. The mixture was ultrasonically sonicated at 400 W for 30 min in an ultrasonic cell disruptor to ensure homogeneity. The resulting black liquid was vacuum filtered to form a positive electrode film with a diameter of 4 cm. The obtained positive electrode film was dried in a 70°C oven and then cut into MnO2 positive electrode films (positive electrode sheets) with a diameter of 8 mm.

[0091] (2) Preparation of negative electrode sheet: A zinc foil of 100mm×100mm×0.3mm was polished with sandpaper, and the polished zinc foil was cut to obtain a zinc foil with a specification of 10mm×10mm×0.3mm.

[0092] (3) Assembly and testing of Zn / / MnO2 full cells: Commercial CR2032 electrode shells were used, and glass fiber (16 mm in diameter) separators were used. 80 μL of electrolyte was added, and the cells were assembled in the following order: negative electrode shell - negative electrode sheet - separator - positive electrode sheet - stainless steel sheet - spring sheet - positive electrode shell. After assembly, the cells were pressurized and sealed to obtain Zn / / MnO2 full cells.

[0093] The electrolytes prepared in Examples 1-6 and Comparative Examples 1-3 were used to assemble the Zn / / Cu battery, Zn / / Zn symmetric battery, and Zn / / MnO2 full cell in Application Examples 1-3, respectively.

[0094] The assembled Zn / / Zn symmetric cells and Zn / / MnO2 full cells were subjected to constant current charge-discharge tests at 25°C. The results are shown in Table 1-2.

[0095] Table 1. Performance test results of Zn / / MnO2 full cells

[0096]

[0097] Table 2 Performance test results of Zn / / Zn symmetric cells

[0098] electrolyte <![CDATA[5mA·cm -2 5mAh·cm -2 Cycle time of symmetrical cells under certain conditions Example 1 1200h Example 2 600h Example 3 450h Example 4 470h Example 5 420h Example 6 480h Comparative Example 1 23h Comparative Example 2 70h Comparative Example 3 220h

[0099] As shown in Table 1, compared with the electrolytes used in Comparative Examples 1 and 2, the rate performance of the Zn / / MnO2 full cells assembled using the electrolytes in Examples 1-6 was significantly improved at current densities of 0.5 A / g and 1 A / g. Furthermore, the capacity retention was significantly improved after 500 cycles at a current density of 1 A / g. Table 2 also shows that the Zn / Zn symmetric cells assembled using the electrolytes in Examples 1-6 achieved a rate performance of 5 mA·cm⁻¹. -2 5mAh·cm -2 Under the given conditions, the battery cycle time was significantly longer than that of Comparative Example 1 and Comparative Example 2, and its long life performance was far superior to that of Comparative Example 3, which used no oxygen-containing functional group (p-aminobenzenesulfonamide). This fully demonstrates that the oxygen-containing functional group, which can act as a hydrogen bond acceptor in this invention, interacts with water molecules to form intermolecular hydrogen bonds and inhibits the activity of water molecules.

[0100] The above results confirm that by introducing the additives of this invention into the electrolyte system, the prepared bifunctional aqueous zinc-ion battery high-voltage electrolyte can induce uniform zinc deposition and growth, reduce the contact between water molecules in the electrolyte and the negative electrode surface, effectively inhibit water-induced corrosion side reactions and hydrogen evolution behavior, and reduce zinc dendrite growth and the formation of dead zinc.

[0101] Zinc foil (10mm × 10mm × 0.3mm) was immersed in the electrolytes prepared in Examples 1 to 4 and Comparative Example 1, respectively. After immersion for one week, the zinc foil was subjected to XRD testing, and the results are shown in the figure. Figure 1 .

[0102] Figure 1 The images show the XRD patterns of zinc foil after being immersed in the electrolytes prepared in Examples 1-4 and Comparative Example 1 for one week. Figure 1 It can be seen that the XRD pattern of the zinc foil (Zn foil) after being soaked in ZnSO4 electrolyte (i.e., Comparative Example 1) for one week clearly shows the characteristic peak of Zn4(OH)6SO4·xH2O (ZHS) byproduct. However, when additives (Examples 1 to 4) are introduced into the electrolyte, no obvious byproduct characteristic peaks are observed. This result reflects that the high-voltage electrolyte of the bifunctional aqueous zinc-ion battery of the present invention can effectively suppress side reactions caused by water molecules.

[0103] Under different current density test conditions, constant current charge-discharge tests were conducted on the Zn / / Zn symmetric cells assembled using the electrolytes prepared in Example 1 and Comparative Example 1, and the corresponding time-voltage curves were plotted. The results are shown in [Figure 1]. Figure 2 .

[0104] Figure 2 Zn / / Zn symmetric cells assembled using the electrolytes prepared in Example 1 and Comparative Example 1 were tested at current densities of 0.5, 1, 2, 5, 10, 15, and 20 mA / cm². 2 Specific capacity is 1mAh / cm³ 2 The constant current charge-discharge curves under the test conditions. Figure 2 The results show that the Zn / / Zn symmetric cell assembled using the electrolyte prepared in Comparative Example 1 has a short cycle life, and a short circuit occurs when the current density increases to 20 mA / cm². 2 At that time, the potential of the Zn / / Zn symmetric cell changed dramatically. The Zn / / Zn symmetric cell assembled using the electrolyte prepared in Example 1 not only could cycle stably for 360 hours at high current density, but also maintained excellent reversibility when the current density decreased.

[0105] At 1mA / cm 2 1mAh / cm 2 Under the specified test conditions, Zn / / Zn symmetric cells assembled using the electrolytes prepared in Examples 1-4 and Comparative Example 1 were subjected to constant current charge-discharge tests, and the corresponding time-voltage curves were plotted. The results are shown in [Figure 1]. Figure 3 .

[0106] Figure 3To test the Zn / / Zn symmetric cells assembled using the electrolytes prepared in Examples 1-4 and Comparative Example 1 at 1 mA / cm 2 1mAh / cm 2 The constant current charge-discharge curves under the test conditions. Figure 3 The results showed that the Zn / / Zn symmetric battery assembled using the electrolyte prepared in Comparative Example 1 had the shortest cycle life, less than 50 hours. The Zn / / Zn symmetric batteries assembled using the electrolytes prepared in Examples 1 to 4 all had longer cycles than Comparative Example 1. The Zn / / Zn symmetric battery assembled using the electrolyte prepared in Example 1 could maintain an excellent long life of 2000 hours. This indicates that the use of additives can inhibit the growth of zinc dendrites and extend the battery life.

[0107] At 4mA / cm 2 1mAh / cm 2 Under the specified test conditions, the coulombic efficiency of Zn / / Cu batteries assembled using the electrolytes prepared in Examples 1-4 and Comparative Example 1 was tested to further explore the Zn plating / stripping process. The results are shown in [Figure number missing]. Figure 4 .

[0108] Figure 4 To test the Zn / / Cu battery assembled using the electrolytes prepared in Examples 1-4 and Comparative Example 1 at 4 mA / cm 2 1mAh / cm 2 Coulomb efficiency under the test conditions. Figure 4 The results show that the coulombic efficiency of the Zn / / Cu battery assembled using the electrolyte prepared in Comparative Example 1 is only 73.5%, while the coulombic efficiencies of the Zn / / Cu batteries assembled using the electrolytes prepared in Examples 1 to 4 are 99.2%, 98.3%, 97.9%, and 95.2%, respectively. This indicates that the electrolyte provided by the present invention can effectively improve anodic reversibility and achieve higher average CE and good cycle stability.

[0109] The effect of electrolyte on zinc plating / stripping behavior was observed using scanning electron microscopy (SEM). Zn / / Zn symmetric cells assembled using the electrolytes prepared in Example 1 and Comparative Example 1 were tested at 1 mA / cm². 2 1mAh / cm 2 SEM images of the Zn foil after 100 cycles under the test conditions are shown below. Figure 5 .

[0110] Figure 5 To test the Zn / / Zn symmetric cells assembled using the electrolytes prepared in Example 1 and Comparative Example 1 at 1 mA / cm 2 1mAh / cm 2SEM images of Zn foil after 100 cycles under the test conditions, where (a) is Comparative Example 1 and (b) is Example 1. Figure 5 It can be seen that after 100 cycles, the Zn / / Zn symmetric cell assembled using the electrolyte prepared in Comparative Example 1 has a large number of zinc dendrites on the surface of the Zn foil. Figure 5 In (a) of the example, these zinc dendrites vary in size and shape, and their accumulation may puncture the separator, leading to a short circuit in the battery. However, the Zn / / Zn symmetric battery assembled using the electrolyte prepared in Example 1 showed a smooth surface on the Zn foil after 100 cycles, exhibiting a dense SEI layer composed of polygonal ZHS flakes. Figure 5 (b) in the figure, and the Zn foil surface still maintains a flat shape, which also confirms the excellent stability of SEI.

[0111] LSV curves were tested on the Zn / / Zn symmetric cells assembled using the electrolytes prepared in Example 1 and Comparative Example 1. The results are shown in [Figure 1]. Figure 6 .

[0112] Figure 6 The LSV curves are for Zn / / Zn symmetric cells assembled using the electrolytes prepared in Example 1 and Comparative Example 1. Figure 6 The results showed that with the addition of additives, the energy required for the hydrogen evolution reaction gradually increased, leading to a gradual decrease in hydrogen evolution activity. This indicates that the electrolyte containing additives can effectively inhibit the HER reaction and expand the electrochemical potential window.

[0113] The rate performance test results of the Zn / / MnO2 full cells assembled using the electrolytes prepared in Example 1 and Comparative Example 1 are shown in the figure. Figure 7 .

[0114] Figure 7 The image shows the rate performance of Zn / / MnO2 full cells assembled using the electrolytes prepared in Example 1 and Comparative Example 1. Figure 7 It can be seen that the specific capacity of the Zn / / MnO2 full cells assembled using the electrolytes prepared in Example 1 and Comparative Example 1 is higher than that of the cells assembled using the electrolyte prepared in Comparative Example 1 at different current densities (0.5A / g, 1A / g, 2A / g, 3A / g). This indicates that the bifunctional aqueous zinc-ion battery high-voltage electrolyte containing additives provided by the present invention can improve the rate performance of the full cell.

[0115] The Zn / / MnO2 full cells assembled using the electrode solutions prepared in Example 1 and Comparative Example 1 were subjected to capacity-voltage (GCD) curve testing at a current density of 0.5 A / g. The results are shown in [Figure 1]. Figure 8 .

[0116] Figure 8The capacity-voltage curves of Zn / / MnO2 full cells assembled using the electrode solutions prepared in Example 1 and Comparative Example 1 are shown at a current density of 0.5 A / g. Figure 8 It can be seen that, at a current density of 0.5 A / g, the Zn / / MnO2 full cell assembled using the electrode solution prepared in Example 1 can maintain a high voltage plateau of about 1.3 V at a current density of 0.5 A / g, and the specific capacity exceeds 520 mAh·g. -1 This fully demonstrates that the dual-functional aqueous zinc-ion battery high-voltage electrolyte provided by the present invention can remain stable under a high voltage window.

[0117] The cycling performance of Zn / / MnO2 full cells assembled using the electrolytes prepared in Example 1 and Comparative Example 1 was tested at a current density of 5 A / g. The results are shown in [Figure 1]. Figure 9 .

[0118] Figure 9 The long-cycle performance of Zn / / MnO2 full cells assembled using the electrolytes prepared in Example 1 and Comparative Example 1 at a current density of 5 A / g is shown. Figure 9 It can be seen that the battery assembled using the electrolyte prepared in Example 1 has a capacity retention rate of up to 78.7% after more than 1100 cycles at a current density of 5 A / g, while the battery assembled using the electrolyte prepared in Comparative Example 1 has a capacity retention rate of only 8.3% after less than 450 cycles at a current density of 5 A / g. This fully demonstrates that the high-voltage electrolyte for the dual-functional aqueous zinc-ion battery provided by the present invention has excellent cycle stability.

[0119] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A dual-functional aqueous high-voltage electrolyte for zinc-ion batteries, characterized in that, It includes the following ingredients: additives, soluble zinc salts, and water; The general structural formula of the additive is: Wherein, R is selected from hydroxyl, carboxyl, acetyl, or methoxy groups; The concentration of soluble zinc salt in the high-voltage electrolyte of the bifunctional aqueous zinc-ion battery is 1–2 mol / L, and the concentration of additives is 0.005–0.015 mol / L.

2. The dual-functional aqueous zinc-ion battery high-voltage electrolyte according to claim 1, characterized in that, The soluble zinc salt is selected from at least one of zinc sulfate, zinc trifluoromethanesulfonate, zinc bis(trifluoromethanesulfonyl)imide, zinc acetate, zinc chloride, and zinc nitrate.

3. A method for preparing a high-voltage electrolyte for a bifunctional aqueous zinc-ion battery as described in any one of claims 1 to 2, characterized in that, Soluble zinc salts are dissolved in water to obtain a soluble zinc salt electrolyte; additives are added to the soluble zinc salt electrolyte, and after heating and stirring, the mixture is cooled to obtain the high-voltage electrolyte for the dual-function aqueous zinc-ion battery.

4. The method for preparing the high-voltage electrolyte for a bifunctional aqueous zinc-ion battery according to claim 3, characterized in that, The heating and stirring temperature is 50℃, the time is 12h, and the stirring speed is 500r / min.

5. An aqueous zinc-ion battery, characterized in that, It includes a negative electrode, a positive electrode, a separator, and an electrolyte; the electrolyte comprises the high-voltage electrolyte for a bifunctional aqueous zinc-ion battery as described in any one of claims 1 to 2.

6. The aqueous zinc-ion battery according to claim 5, characterized in that, The negative electrode is selected from at least one of zinc sheet, zinc foil, zinc powder, and zinc alloy; The positive electrode is selected from zinc sheet, copper foil, or active material electrode film; the active material in the active material electrode film is selected from at least one of manganese-based compounds and vanadium-based compounds. The diaphragm is selected from at least one of glass fiber membrane and nonwoven fabric.

7. The aqueous zinc-ion battery according to claim 5, characterized in that, The electrolyte also includes cations corresponding to the active materials in the active material electrode film.

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