Novel sulfonic acid-based electrolyte and application thereof in aqueous zinc ion battery

Abstract

The invention discloses a novel sulfonic acid-based electrolyte and an application thereof in an aqueous zinc ion battery, and belongs to the technical field of aqueous energy storage batteries. The sulfonic acid-based electrolyte is prepared by taking soluble zinc salt as electrolyte salt, sulfanilic acid as an additive and high-purity deionized water as a solvent. In the invention, p-aminobenzene sulfonic acid is used as an additive, lone pair electrons in molecules provide hydrogen bond sites through nitrogen and oxygen elements, and form hydrogen bonds with water molecules in the electrolyte, so that double electrode layer reconstruction of an interface is caused. The hydrogen bonds not only limit the corrosion of free water molecules to the surface of the zinc anode, but also promote the desolvation process of the zinc anode and accelerate the Zn < 2 + > diffusion kinetics between the electrolyte and the electrode. Besides, the additive can be adsorbed on a zinc anode through amino groups and sulfonic groups, a metal-electrolyte interface is stabilized, and zinc ions are induced to be uniformly deposited along a 002 crystal face, so that formation and growth of zinc dendrites are inhibited, and the durability of a battery is enhanced.

Description

Technical Field

[0001] This invention belongs to the field of aqueous energy storage battery technology, specifically relating to a novel sulfonic acid-based electrolyte and its application in aqueous zinc-ion batteries. Background Technology

[0002] In recent years, with climate change and the variability of renewable energy, developing robust grid-scale energy storage technologies has become an urgent problem to be solved. Among these, aqueous zinc-ion batteries have emerged as a particularly promising option. These batteries offer significant advantages, including a capacity of 820 mAh / g. -1 / 5855mAh·cm -2 The high theoretical capacity, low redox potential of -0.76V vs SHE, safety, environmental friendliness, and cost-effectiveness of aqueous zinc-ion batteries have attracted great attention from the research community and industry. Despite the development potential of aqueous zinc-ion batteries, problems such as dendrite growth, metal corrosion, and hydrogen evolution lead to instability at the electrode / electrolyte interface, resulting in decreased battery capacity, low coulombic efficiency, and short cycle life, severely hindering their practical application. Solving these problems, especially improving the stability of the electrode-electrolyte interface, is crucial for commercial viability. In recent years, various strategies have been explored to improve the durability and reversibility of zinc anodes, including advanced structural design, separator modification, surface coating, electrolyte optimization, and alloying. Among these, electrolyte additives offer a direct, effective, and environmentally friendly solution to alleviate the aforementioned challenges. Summary of the Invention

[0003] To address the aforementioned technical problems, the purpose of this invention is to provide a novel sulfonic acid-based electrolyte and its application in aqueous zinc-ion batteries.

[0004] The objective of this invention is achieved through the following technical solution: a novel sulfonic acid-based electrolyte, prepared using a soluble zinc salt as the electrolyte salt, p-aminobenzenesulfonic acid as an additive, and high-purity deionized water as the solvent.

[0005] Furthermore, the soluble zinc salt is selected from one or more of zinc sulfate, zinc chloride, zinc acetate, or zinc trifluoromethanesulfonate.

[0006] Furthermore, the concentration of the soluble zinc salt is 1 mol·L⁻¹. -1 -3mol·L -1 ; preferably 2 mol·L -1 .

[0007] Furthermore, the concentration of the p-aminobenzenesulfonic acid is 0.03 mol·L⁻¹. -1 -0.07 mol·L -1 .

[0008] This invention provides the application of a novel sulfonic acid-based electrolyte as a battery electrolyte in aqueous zinc-ion batteries.

[0009] Furthermore, the aqueous zinc-ion battery includes an aqueous zinc-ion symmetric battery, an aqueous zinc-ion asymmetric battery, and an aqueous zinc-ion full battery.

[0010] Furthermore, the aqueous zinc-ion symmetric battery is a symmetric battery composed of zinc foil as both positive and negative electrode plates, glass fiber as separator, and the aforementioned novel sulfonic acid-based electrolyte.

[0011] Furthermore, the aqueous zinc-ion asymmetric battery is an asymmetric battery composed of zinc foil as the negative electrode, copper foil as the positive electrode, glass fiber as the separator, and the aforementioned novel sulfonic acid-based electrolyte.

[0012] Furthermore, the aqueous zinc-ion full battery is a full battery composed of zinc foil as the negative electrode, vanadium dioxide as the positive electrode, glass fiber as the separator, and the aforementioned novel sulfonic acid-based electrolyte.

[0013] Further, the method for preparing the positive electrode sheet includes the following steps: vanadium dioxide, conductive carbon black, and polyvinylidene fluoride are mixed in a mass ratio of 7:2:1, ground uniformly, and a positive electrode slurry is prepared using N-methylpyrrolidone as a solvent. This slurry is then coated onto a stainless steel mesh using a scraper and vacuum dried to obtain the positive electrode sheet; the vanadium dioxide loading is 2 mg·cm³. -2 -3mg·cm -2 .

[0014] The beneficial effects of this invention are:

[0015] 1. This invention uses p-aminobenzenesulfonic acid as a novel electrolyte additive. The lone pair electrons in the p-aminobenzenesulfonic acid molecule provide hydrogen bonding sites through nitrogen and oxygen elements, forming hydrogen bonds with water molecules in the electrolyte, causing a reconstruction of the electrical double layer at the interface. These hydrogen bonds not only limit the corrosion of the zinc anode surface by free water molecules but also promote the desolvation process of the zinc anode, accelerating the bonding between the electrolyte and the electrode. 2+ Diffusion kinetics.

[0016] 2. In this invention, p-aminobenzenesulfonic acid, as an electrolyte additive, can be adsorbed onto the zinc anode through amino and sulfonic acid groups, stabilizing the metal-electrolyte interface, inducing zinc ions to be uniformly deposited along the 002 crystal plane, thereby inhibiting the formation and growth of zinc dendrites and enhancing the battery's durability.

[0017] 3. This invention utilizes p-aminobenzenesulfonic acid as an additive, which possesses inherent advantages such as low cost, safety, simple preparation method, and wide applicability. It has significant application prospects and research value in the field of new energy batteries. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the contact angle test of two electrolytes in Embodiment 1 of the present invention.

[0019] Figure 2 Examples of Zn||Zn symmetric cells with different electrolyte systems in Embodiment 1 of the present invention are shown at 1 mA·cm -2 / 1mAh·cm -2 A comparison of charge-discharge curves under the given conditions.

[0020] Figure 3 Example 1 of this invention describes Zn||Zn symmetric cells with different electrolyte systems at 5 mA·cm⁻¹. -2 / 5mAh·cm -2 A comparison of charge-discharge curves under the given conditions.

[0021] Figure 4 This is a comparison chart of the rate performance of Zn||Zn symmetric batteries with different electrolyte systems in Example 1 of the present invention.

[0022] Figure 5 Examples of Zn||Zn symmetric cells with different electrolyte systems in Embodiment 1 of the present invention are shown at 1 mA·cm -2 / 0.5mAh·cm -2 SEM comparison images of the zinc anode surface after 70 cycles under the specified conditions.

[0023] Figure 6 This is a coulombic efficiency diagram of Zn||Cu asymmetric batteries with different electrolyte systems in Example 2 of the present invention.

[0024] Figure 7 Example 3 of this invention presents Zn||VO2 full cells with different electrolyte systems at 1 A·g -1 Comparison of constant current charge-discharge curves under current density.

[0025] Figure 8 Example 3 of this invention describes Zn||VO2 full cells with different electrolyte systems at 5 A·g. -1 Comparison of constant current charge-discharge curves under current density. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. The specific embodiments described herein are merely illustrative and not intended to limit the scope of the invention.

[0027] Unless otherwise defined, the technical terms used below have the same meaning as understood by those skilled in the art; unless otherwise specified, the raw materials and reagents in the embodiments of the present invention can be purchased commercially or prepared by known methods.

[0028] The button battery used in the following examples is model CR2032.

[0029] Experimental Example 1: Application of a novel sulfonic acid-based electrolyte as a battery electrolyte in an aqueous zinc-ion symmetric battery.

[0030] (I) Preparation of battery electrolyte

[0031] This invention relates to the preparation of a sulfonic acid-based electrolyte: At room temperature, 5.75 g of zinc sulfate and 0.1212 g of p-aminobenzenesulfonic acid were added to 10 mL of deionized water, and the mixture was ultrasonically stirred until the solution became clear, yielding a zinc sulfate concentration of 2 mol·L⁻¹. -1 The concentration of p-aminobenzenesulfonic acid was 0.07 mol·L⁻¹. -1 The sulfonic acid-based electrolyte is abbreviated as ZS-SA.

[0032] Comparative Example – Preparation of Zinc Sulfate Electrolyte: At room temperature, 5.75 g of zinc sulfate was added to 10 mL of deionized water, and the solution was ultrasonically stirred until clear, yielding a zinc sulfate concentration of 2 mol·L⁻¹. -1 Zinc sulfate electrolyte, abbreviated as ZS.

[0033] (II) Assembly of aqueous zinc-ion symmetric button cell (Zn||Zn symmetric cell)

[0034] Cut high-purity zinc foil (99.99% purity) with a thickness of 100μm into round pieces with a diameter of 12mm for later use.

[0035] Cut the fiberglass diaphragm into 16mm diameter circular pieces for later use.

[0036] Assembly: Zinc foil is used as the positive and negative electrodes of the button cell. First, the positive electrode is placed in the positive electrode shell, then a glass fiber separator is placed in, followed by 80 μL of ZS and ZS-SA electrolytes respectively. Then, the negative electrode is placed in, followed by a spacer and a spring. Finally, the negative electrode shell is closed, and the battery is sealed using a battery packaging machine. This yields two types of aqueous zinc-ion symmetric button cells (Zn||Zn symmetric cells) using zinc sulfate electrolyte and sulfonic acid electrolyte respectively.

[0037] (III) Electrochemical Performance Testing

[0038] Using a blue battery testing instrument, constant current charge-discharge tests were conducted at different current densities to analyze the cycle performance of different electrolytes.

[0039] 1. The prepared sulfonic acid-based electrolyte ZS-SA and zinc sulfate electrolyte ZS were respectively added dropwise to the zinc negative electrode, and the contact angle was tested. The results are as follows: Figure 1 As shown. The left figure is a schematic diagram of the contact angle after adding ZS electrolyte; the right figure is a schematic diagram of the contact angle after adding ZS-SA electrolyte. Figure 1 It can be seen that after adding p-aminobenzenesulfonic acid, the contact angle between the electrolyte and zinc decreased from 101.1° to 72.1°, indicating that p-aminobenzenesulfonic acid enhanced interfacial wettability, helped reduce interfacial free energy, and promoted the rapid and uniform transfer and nucleation of zinc ions. The change in contact angle is mainly due to the strong adsorption behavior of p-aminobenzenesulfonic acid additive molecules on the zinc surface. This behavior reduces the entry of water molecules into the electrode / electrolyte interface, thereby reducing interfacial corrosion and inhibiting interfacial side reactions.

[0040] 2. The Zn||Zn symmetric cells were tested at 1 mA·cm⁻¹. -2 / 1mAh·cm -2 and 5mA·cm -2 / 5mAh·cm -2 Under these conditions, a constant current charge-discharge cycle test was performed, with the cycle time as follows: Figure 2 and Figure 3 As shown, at low current densities, the Zn||Zn symmetric cell without p-aminobenzenesulfonic acid experienced a short circuit in less than 200 hours of cycling; while the Zn||Zn symmetric cell with p-aminobenzenesulfonic acid added achieved a cycle time of up to 2600 hours, significantly extending the cell's cycle life. Similarly, at 5 mA·cm -2 / 5mAh·cm -2 Under certain conditions, a symmetric cell with pure zinc sulfate electrolyte can only cycle for less than 100 hours, while a Zn||Zn symmetric cell with added p-aminobenzenesulfonic acid can cycle stably for 450 hours, which is four times longer than the unadded one.

[0041] 3. The Zn||Zn symmetric cell is transferred from 1 mA·cm⁻¹ -2 -30mA·cm -2 Perform a multiplier cycle test, and the cycle times for each are as follows: Figure 4 As shown. The Zn||Zn symmetric cell without the addition of p-aminobenzenesulfonic acid, when the current density increases from 10 mA·cm⁻¹... -2 Dropped back to 5 mA·cm -2 Subsequently, as the voltage gradually increases, the battery experiences a soft short circuit; however, the Zn||Zn symmetric battery with added p-aminobenzenesulfonic acid can cycle stably at various current densities and exhibits good rate cycling performance.

[0042] 4. A Zn||Zn symmetric cell is subjected to 1 mA·cm⁻¹ -2 / 0.5mAh·cm -2 Under these conditions, a constant current charge-discharge cycle test of 70 times was conducted. Figure 5The image shows a surface SEM image of the zinc anode after cycling. It can be seen that the zinc sheet surface of the Zn||Zn symmetric cell with p-aminobenzenesulfonic acid added has a regular stack of regular hexagonal layers, indicating that the electrolyte containing p-aminobenzenesulfonic acid can induce zinc ions to deposit uniformly along the 002 crystal plane. However, the zinc sheet surface of the Zn||Zn symmetric cell without the additive shows a large number of anisotropic lamellar dendrites, which will further lead to short circuits in the cell.

[0043] Experimental Example 2: Application of a novel sulfonic acid-based electrolyte as a battery electrolyte in an aqueous zinc-ion asymmetric battery.

[0044] (I) Preparation of battery electrolyte

[0045] Preparation of sulfonic acid-based electrolyte in this invention: same as in Example 1.

[0046] Comparative Example – Preparation of Zinc Sulfate Electrolyte: Same as Example 1.

[0047] (II) Assembly of aqueous zinc-ion asymmetric button cell (Zn||Cu asymmetric cell)

[0048] Cut high-purity zinc foil (99.99% purity) with a thickness of 100μm into round pieces with a diameter of 12mm for later use.

[0049] Cut the fiberglass diaphragm into 16mm diameter circular pieces for later use.

[0050] Cut the copper foil into 12mm round pieces and set aside.

[0051] Assembly: Copper foil is used as the positive electrode of the button cell, and zinc foil is used as the negative electrode. The remaining steps are the same as those for assembling a symmetrical button cell in Example 1.

[0052] (III) Electrochemical Performance Testing

[0053] Using a blue battery testing instrument, constant current charge-discharge tests were conducted at a certain current density to obtain the coulombic efficiency of asymmetric batteries with different electrolytes, so as to analyze their stability and reversibility.

[0054] A Zn||Cu asymmetric cell was used at 4 mA·cm -2 / 1mAh·cm -2 Perform constant current charge-discharge cycle tests under the following conditions, such as Figure 6 As shown, the coulombic efficiency of the Zn||Cu asymmetric cell with added p-aminobenzenesulfonic acid reached 99.7% after 1350 cycles, while the unadded Zn||Cu asymmetric cell failed rapidly in less than 600 cycles. This indicates that the addition of p-aminobenzenesulfonic acid can significantly improve the stability of zinc-ion cells and the reversibility of zinc deposition / stripping.

[0055] Experimental Example 3: Application of a novel sulfonic acid-based electrolyte as a battery electrolyte in an aqueous zinc-ion full battery.

[0056] (I) Preparation of battery electrolyte

[0057] Preparation of sulfonic acid-based electrolyte in this invention: same as in Example 1.

[0058] Comparative Example – Preparation of Zinc Sulfate Electrolyte: Same as Example 1.

[0059] (II) Assembly of aqueous zinc-ion full cells (Zn||VO2 full cells)

[0060] Cut high-purity zinc foil (99.99% purity) with a thickness of 100μm into round pieces with a diameter of 12mm for later use.

[0061] Cut the fiberglass diaphragm into 16mm diameter circular pieces for later use.

[0062] Cut the stainless steel mesh into 12mm round pieces and set aside.

[0063] Aqueous zinc-ion full battery, with vanadium dioxide as the positive electrode active material, is assembled using the following steps:

[0064] Preparation of the positive electrode sheet: Vanadium dioxide, conductive carbon black, and polyvinylidene fluoride were mixed in a mass ratio of 7:2:1 and ground evenly in a mortar. Using N-methylpyrrolidone as a solvent, a positive electrode slurry was prepared. This slurry was coated onto a stainless steel mesh using a scraper and vacuum dried at 60°C for 12 hours to obtain the positive electrode sheet. The vanadium dioxide loading was 2.5 mg·cm³. -2 .

[0065] Assembly: The electrode sheet prepared above is used as the positive electrode sheet of the button cell, and the zinc foil is used as the negative electrode sheet. The remaining steps are the same as those in Example 1 for assembling a symmetrical button cell.

[0066] (III) Electrochemical Performance Testing

[0067] Using a blue battery testing instrument, constant current charge-discharge tests were conducted at two different current densities to analyze the cycle life and capacity retention of different electrolytes.

[0068] At a current density of 1 A·g -1 and 5A·g -1 The following constant current charge-discharge test was performed on the Zn||VO2 full cell, and the results are as follows: Figure 7 and Figure 8 As shown. The results indicate that during cycling at both current densities, the Zn||VO2 full cell containing the p-aminobenzenesulfonic acid additive is always more stable than the one without the additive, and the Zn||VO2 full cell containing p-aminobenzenesulfonic acid exhibits a higher capacity retention. The results also show that at 1 A·g-1 At the specified current density, the Zn||VO2 full cell containing p-aminobenzenesulfonic acid electrolyte additive can stably cycle for 600 cycles with a capacity retention of 58.83%, while the Zn||VO2 full cell without additive exhibits rapid capacity decay, with a capacity retention of only 26.49% after 600 cycles; similarly, at 5 A·g -1 At current density, Zn||VO2 full cells containing p-aminobenzenesulfonic acid electrolyte additive showed better stability and higher capacity retention than those without additive, confirming the possibility of p-aminobenzenesulfonic acid as an electrolyte additive in practical applications.

[0069] Based on the above embodiments and test data, it can be seen that the method of the present invention is simple, low-cost, and effective, and is of great significance for suppressing dendrite growth and side reactions in aqueous zinc-ion batteries and promoting the long-life application of aqueous zinc-ion batteries in the future.

[0070] The above description is merely a few embodiments of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any modifications or alterations made by those skilled in the art without departing from the scope of the technical solution of the present invention using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A novel sulfonic acid-based electrolyte, characterized in that, The sulfonic acid-based electrolyte is prepared using soluble zinc salt as the electrolyte salt, p-aminobenzenesulfonic acid as an additive, and high-purity deionized water as the solvent.

2. The novel sulfonic acid-based electrolyte according to claim 1, characterized in that, The soluble zinc salt is selected from one or more of zinc sulfate, zinc chloride, zinc acetate, or zinc trifluoromethanesulfonate.

3. A novel sulfonic acid-based electrolyte according to claim 1 or 2, characterized in that, The concentration of the soluble zinc salt is 1 mol·L⁻¹. -1 -3mol·L -1 .

4. A novel sulfonic acid-based electrolyte according to claim 1 or 2, characterized in that, The concentration of p-aminobenzenesulfonic acid is 0.03 mol·L⁻¹. -1 -0.07 mol·L -1 .

5. The application of the novel sulfonic acid-based electrolyte as described in any one of claims 1-4 as a battery electrolyte in an aqueous zinc-ion battery.

6. The application according to claim 5, characterized in that, The aqueous zinc-ion battery includes an aqueous zinc-ion symmetric battery, an aqueous zinc-ion asymmetric battery, and an aqueous zinc-ion full battery.

7. The application according to claim 6, characterized in that, The aqueous zinc-ion symmetric battery is a symmetric battery composed of zinc foil as both positive and negative electrode plates, glass fiber as separator, and the novel sulfonic acid-based electrolyte as described in any one of claims 1-4.

8. The application according to claim 6, characterized in that, The aqueous zinc-ion asymmetric battery is an asymmetric battery composed of zinc foil as the negative electrode, copper foil as the positive electrode, glass fiber as the separator, and the novel sulfonic acid-based electrolyte as described in any one of claims 1-4.

9. The application according to claim 6, characterized in that, The aqueous zinc-ion full battery is a full battery composed of zinc foil as the negative electrode, vanadium dioxide as the positive electrode, glass fiber as the separator, and the novel sulfonic acid-based electrolyte as described in any one of claims 1-4.

10. The application according to claim 9, characterized in that, The method for preparing the positive electrode sheet includes the following steps: vanadium dioxide, conductive carbon black, and polyvinylidene fluoride are mixed in a mass ratio of 7:2:1, ground evenly, and a positive electrode slurry is prepared using N-methylpyrrolidone as a solvent. This slurry is then coated onto a stainless steel mesh using a scraper and vacuum dried to obtain the positive electrode sheet; the vanadium dioxide loading is 2 mg·cm³. -2 -3mg·cm -2 .

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