A hydroxylated zwitterionic additive and a method for preparing the same, zinc-based battery electrolyte

Abstract

This invention relates to the field of zinc-based battery electrolyte technology, and more particularly to a hydroxylated zwitterionic additive and its preparation method, as well as a zinc-based battery electrolyte. This invention provides a hydroxylated zwitterionic additive for zinc-based battery electrolytes, which can simultaneously act on the three-phase system of the positive electrode, negative electrode, and electrolyte, achieving multi-dimensional synergistic optimization.

Description

Technical Field

[0001] This invention relates to the field of zinc-based battery electrolyte technology, and in particular to a hydroxylated zwitterionic additive and its preparation method, as well as a zinc-based battery electrolyte. Background Technology

[0002] Aqueous zinc-based batteries are characterized by high safety (no flammable electrolyte) and high theoretical capacity (zinc's volumetric capacity is 820 mA·h·cm³). -3 Zinc-iodine batteries are widely considered ideal candidate technologies for large-scale energy storage and portable electronic devices due to their advantages such as high energy density, low cost (abundant zinc resources, with a crustal abundance of 2.3%), and environmental friendliness. Among them, zinc-iodine batteries, with their higher energy density (theoretical energy density of 420 W·h·kg⁻¹), are particularly promising. -1 The faster redox kinetics of zinc-based batteries have made them a focus of research in thermoelectricity, but their commercialization is still limited by severe multiphase interface problems, specifically: 1) Positive electrode side: The redox reaction of iodine depends on soluble polyiodides (such as I3) - I5 - To expand the reaction network and improve reaction kinetics, these polyiodides are highly mobile and easily shuttle across the membrane to the negative electrode, where they react chemically with zinc (Zn + I₃). - →Zn 2+ +3I - This leads to the loss of positive electrode active material and negative electrode corrosion, ultimately causing rapid capacity decay and a decrease in coulombic efficiency. In existing technologies, shuttle transport is suppressed through membrane modification (such as layering and pore size control) or electrolyte additives (such as cationic surfactants). However, membrane modification increases ion transport resistance, and additives can only capture polyiodides through a single electrostatic interaction, with limited effectiveness and a tendency to slow down reaction kinetics; 2) Negative electrode side: In aqueous electrolytes, Zn 2+ The solvation structure (mainly [Zn(H2O)6)) 2+ It is unstable and prone to forming irregular zinc dendrites during deposition. Dendrite growth can pierce the diaphragm and cause a short circuit. At the same time, hydrogen evolution side reaction (2H2O + 2e-) is unavoidable in aquatic environments. - →H2+2OH - This leads to an increase in electrolyte pH and corrosion of the zinc electrode, further deteriorating battery stability. Existing solutions include electrode surface modification (such as carbon coating) and the addition of dendrite inhibitors (such as metal ions and organophosphonic acids) to the electrolyte. However, these methods mostly address only a single dendrite or side reaction problem and cannot simultaneously address the issue of Zn. 2+3) Electrolyte side: Existing zinc-based battery electrolytes are mostly single-salt solutions (such as ZnSO4), which have insufficient ion transport efficiency and pH stability, and cannot adapt to the differentiated needs of positive and negative electrodes. For example, the positive electrode requires the electrolyte to maintain the appropriate dissolution of polyiodides to ensure kinetics, while the negative electrode requires the electrolyte to suppress water activity to reduce side reactions. A single electrolyte system is difficult to balance this contradiction, resulting in limited overall battery performance; 4) Limitations of existing additives: Zwitterions, because they have both positive and negative polarity functional groups, have been attempted for electrolyte interface regulation. However, traditional zwitterions only rely on electrostatic interactions with electrodes or ions, lacking directional molecular binding ability, and cannot simultaneously adapt to the complex chemical environment of positive and negative electrodes and electrolytes, making it difficult to achieve multi-phase interface synergistic optimization. Therefore, it is evident that the above-mentioned multi-interface synergistic instability problem cannot be solved at present. Summary of the Invention

[0003] In view of this, the purpose of this invention is to provide a hydroxylated zwitterionic additive and its preparation method, as well as a zinc-based battery electrolyte. The hydroxylated zwitterionic additive can simultaneously act on the three-phase system of the positive electrode, negative electrode, and electrolyte, achieving multi-dimensional synergistic optimization.

[0004] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a hydroxylated zwitterionic additive for zinc-based battery electrolytes, having the structure shown in Formula 1: Formula 1; R1, R2, and R3 are all alkyl groups, and the alkyl groups include hydroxyl groups.

[0005] Preferably, the hydroxyl group includes a terminal hydroxyl group.

[0006] Preferably, the alkyl group has 1 to 5 carbon atoms.

[0007] Preferably, R1, R2 and R3 are all hydroxyethyl.

[0008] This invention also provides a method for preparing the hydroxylated zwitterionic additive described in the above technical solution, comprising the following steps: A compound having the structure shown in Formula 2, 1,3-propylsulfonate lactone, and an organic solvent were mixed and subjected to an affinity ring-opening addition reaction to obtain the hydroxylated zwitterionic additive. Formula 2.

[0009] Preferably, the molar ratio of the compound having the structure shown in Formula 2 to 1,3-propylsulfonate lactone is 1:(1~6).

[0010] Preferably, the nucleophilic ring-opening addition reaction is carried out at a temperature of 40°C for 72 hours. The nucleophilic ring-opening addition reaction was carried out under stirring.

[0011] The present invention also provides a zinc-based battery electrolyte, comprising zinc sulfate and hydroxylated zwitterionic additives; The hydroxylated zwitterionic additive is the hydroxylated zwitterionic additive described in the above technical solution or the hydroxylated zwitterionic additive prepared by the preparation method described in the above technical solution.

[0012] Preferably, the concentration of zinc sulfate in the zinc-based battery electrolyte is 0.5~3 mol / L.

[0013] Preferably, the concentration of the hydroxylated zwitterionic additive in the zinc-based battery electrolyte is 0.5~500 mmol / L.

[0014] This invention provides a hydroxylated zwitterionic additive for zinc-based battery electrolytes, having the structure shown in Formula 1: Formula 1; R1, R2, and R3 are all alkyl groups, and the alkyl groups include hydroxyl groups.

[0015] This invention combines zwitterions with hydroxyl groups, resulting in molecules containing three types of functional groups: sulfonates, quaternary ammonium salts, and hydroxyl groups. These functional groups are linked by alkyl chains to form a close-packed arrangement in space, providing a structural basis for synergistic effects at multiphase interfaces. For negative electrode side regulation, the sulfonate-hydroxyl synergistic effect can disrupt Zn. 2+ Hydrated shell ([Zn(H2O)6) 2+ Decoupling Zn 2+ -SO4 2- The interaction between the ammonium and hydroxyl groups forms a dense and uniform solid electrolyte interface on the electrode surface, inhibiting zinc dendrite growth and electrode corrosion. For the positive electrode side, the ammonium-hydroxyl group, through electrostatic and ion-dipole interactions, synergistically captures polyiodides, maintaining their electrochemically active concentration on the electrode surface. This prevents their transmembrane migration, reduces the loss rate of active materials, and ensures stable reaction kinetics. For the electrolyte side, the hydroxyl group forms a dense hydrogen bond network with water molecules in the electrolyte, reducing water activity and optimizing Zn activity. 2+This invention exhibits a solvation structure and transport efficiency, along with excellent pH buffering capacity. Furthermore, it combines charge regulation with directional molecular binding. The molecule is based on a betaine-type skeleton, incorporating sulfonate, quaternary ammonium, and hydroxyl functional groups. These groups are linked by short-chain spacer arms composed of -C3H6- and short-chain alkyl groups, thus controlling the spacing between hydroxyl and sulfonate ions, and between hydroxyl and quaternary ammonium ions, within 10 Å. This places them within the optimal range for synergistic binding recognized in supramolecular chemistry and enzyme systems. This spatial arrangement allows hydroxyl groups to dynamically participate in forming cation-hydroxyl or anion-hydroxyl interaction pairs based on the local ionic environment. Ultimately, the hydroxylated zwitterionic additive can adopt two adaptive interaction modes to address the drastically different chemical environments of the positive and negative electrodes in zinc-iodine batteries: at the positive electrode, cation-hydroxyl interaction pairs can capture polyiodide ions and suppress their shuttle effect; at the negative electrode, anion-hydroxyl interaction pairs predominate, promoting Zn... 2+ Desolvation and guidance of uniform zinc deposition; and switching between the above-mentioned different modes of action, thereby achieving adaptive interface control at both positive and negative electrodes (e.g. Figure 2 (as shown) Meanwhile, the hydroxylated zwitterionic additive of the present invention can significantly suppress side reactions: reconstruct the interfacial hydrogen bond network, reduce water activity, and suppress hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), thereby greatly reducing the amount of gas generated during the operation of zinc-based batteries and further improving safety and cycle stability; Meanwhile, the hydroxylated zwitterionic additive of the present invention has good compatibility with commonly used electrolytes in zinc-based batteries, and the synthesis and electrolyte preparation processes are simple, requiring no special equipment and easy to scale up production.

[0016] According to the embodiments described, the hydroxylated zwitterionic additive of the present invention exhibits excellent cycle stability when applied to Zn||Zn symmetric cells and zinc-iodine full cells. Attached Figure Description

[0017] Figure 1 This represents the adaptive interaction mode of the hydroxylated zwitterionic additive described in this invention; Figure 2 This is a schematic diagram of the molecular structure of HPS in this invention.

[0018] Figure 3 The HPS described in Example 1 1 H NMR spectrum; Figure 4 The MALDI-TOF plot of HPS described in Example 1; Figure 5 The cycle stability curve of the Zn||Zn symmetric cell described in Example 1; Figure 6The cycle stability curve of the Zn||Zn symmetric cell described in Example 2; Figure 7 The cycling stability curve of the Zn||Zn symmetric cell described in Example 3; Figure 8 The cycle stability curve of the Zn||Zn symmetric cell described in Comparative Example 1; Figure 9 The cycling stability curve of the zinc-iodine full cell assembled with the zinc sulfate solution described in Comparative Example 1 is shown. Figure 10 The cycling stability curve of the zinc-iodine full cell assembled with the zinc-based battery electrolyte described in Example 2 is shown. Figure 11 The pH buffering behavior of the zinc-based battery electrolyte (corresponding to the solid sphere HPS) described in Example 2 and the zinc sulfate solution (corresponding to the solid sphere Bare) described in Comparative Example 1 during dilute hydrochloric acid titration, as well as the pH values ​​of zinc-based battery electrolytes containing different concentrations of HPS (corresponding to the hollow sphere). Figure 12 Linear sweep voltammetric curves of the zinc-iodine full cell (corresponding to Bare) assembled with zinc sulfate solution in Comparative Example 1 and the zinc-iodine full cell (corresponding to HPS) assembled with zinc-based battery electrolyte in Example 2 (where HER is hydrogen evolution reaction and OER is oxygen evolution reaction). Figure 13 The image shows the cycle stability curve of the Zn||Zn symmetric cell described in Comparative Example 2. Detailed Implementation

[0019] This invention provides a hydroxylated zwitterionic additive for zinc-based battery electrolytes, having the structure shown in Formula 1: Formula 1; R1, R2, and R3 are all alkyl groups, and the alkyl groups include hydroxyl groups.

[0020] In this invention, the hydroxyl group preferably includes a terminal hydroxyl group.

[0021] In this invention, the number of carbon atoms in the alkyl group is preferably 1 to 5, more preferably 1, 2, 3, 4 or 5.

[0022] In this invention, R1, R2, and R3 are all preferably hydroxyethyl. That is, the hydroxylated zwitterionic additive is 3-(tris(2-hydroxyethyl)ammonium)propane-1-sulfonate (denoted as HPS, molecular formula C9H). 21 NO6S, with a theoretical molecular weight of 271.1, is a white powder that is readily soluble in water and DMSO, but insoluble in organic solvents such as acetonitrile; its thermal decomposition temperature is >200℃. The structural formula of the HPS is: In this invention, the distance between the hydroxyl group and the sulfonate ion in the HPS is approximately 4.8 Å, and the distance between the hydroxyl group and the quaternary ammonium ion is approximately 4.4 Å (e.g., ...). Figure 2 As shown in the figure, it is in the optimal range for the synergistic combination of supramolecular chemistry and enzyme system.

[0023] This invention also provides a method for preparing the hydroxylated zwitterionic additive described in the above technical solution, comprising the following steps: A compound having the structure shown in Formula 2, 1,3-propylsulfonate lactone, and an organic solvent were mixed and subjected to an affinity ring-opening addition reaction to obtain the hydroxylated zwitterionic additive. Formula 2; In Formula 2, R1, R2, and R3 are independently alkyl groups, and the alkyl groups include hydroxyl groups.

[0024] In this invention, unless otherwise specified, all raw materials used in the preparation are commercially available products well known to those skilled in the art.

[0025] In this invention, the organic solvent preferably includes one or more of ethyl acetate, acetone, and N,N-dimethylformamide, more preferably ethyl acetate; when the organic solvent is two or more of the above-mentioned specific selections, this invention does not impose any special limitation on the ratio of the above-mentioned specific substances, and they can be mixed in any ratio. In the embodiments of this invention, the organic solvent can be ethyl acetate.

[0026] In this invention, the molar ratio of the compound having the structure shown in Formula 2 to 1,3-propylsulfonate lactone is preferably 1:(1 to 6), more preferably 1:1, 1:2, 1:3, 1:4, 1:5, or 1:6. In embodiments of this invention, the molar ratio of the compound having the structure shown in Formula 2 to 1,3-propylsulfonate lactone can be 1:1.

[0027] The present invention does not impose any special limitation on the amount of the organic solvent used; any amount known to those skilled in the art can be used to ensure the smooth progress of the reaction.

[0028] The present invention does not impose any special limitations on the mixing process; any process known to those skilled in the art can be used.

[0029] In this invention, the temperature of the nucleophilic ring-opening addition reaction is preferably 40-50°C, more preferably 40°C, 42°C, 44°C, 46°C, 48°C, or 50°C, and the time is preferably 24-120 hours, more preferably 24 hours, 48 ​​hours, 72 hours, 96 hours, or 120 hours. In an embodiment of this invention, the temperature of the nucleophilic ring-opening addition reaction can be 40°C, and the time can be 72 hours.

[0030] In this invention, the nucleophilic ring-opening addition reaction is preferably carried out under stirring conditions. This invention does not impose any special limitations on the stirring process, and any process well known to those skilled in the art can be used.

[0031] After the nucleophilic ring-opening addition reaction is completed, the present invention preferably includes sequential filtration, washing, and drying. The washing agent is preferably ethyl acetate, and the drying method is preferably vacuum drying. The present invention does not impose any special limitations on the filtration, washing, and vacuum drying processes; any process well-known to those skilled in the art can be used.

[0032] The present invention also provides a zinc-based battery electrolyte, comprising zinc sulfate and hydroxylated zwitterionic additives; The hydroxylated zwitterionic additive is the hydroxylated zwitterionic additive described in the above technical solution or the hydroxylated zwitterionic additive prepared by the preparation method described in the above technical solution.

[0033] In this invention, the concentration of zinc sulfate in the zinc-based battery electrolyte is preferably 0.5~3 mol / L, more preferably 0.5 mol / L, 1 mol / L, 1.5 mol / L, 2 mol / L, 2.5 mol / L, or 3 mol / L. In an embodiment of this invention, the concentration of zinc sulfate in the zinc-based battery electrolyte can be 2 mol / L.

[0034] In this invention, the concentration of the hydroxylated zwitterionic additive in the zinc-based battery electrolyte is preferably 0.5~500 mmol / L, more preferably 0.5 mmol / L, 1 mmol / L, 50 mmol / L, 100 mmol / L, 150 mmol / L, 200 mmol / L, 250 mmol / L, 300 mmol / L, 350 mmol / L, 400 mmol / L, 450 mmol / L, or 500 mmol / L. In embodiments of this invention, the concentration of the hydroxylated zwitterionic additive in the zinc-based battery electrolyte can be 1 mmol / L, 50 mmol / L, or 100 mmol / L.

[0035] In this invention, the zinc-based battery electrolyte preferably includes water, and the water is preferably deionized water.

[0036] In this invention, the method for preparing the zinc-based battery electrolyte preferably includes the following steps: Zinc sulfate and water are mixed to obtain the matrix electrolyte; The zinc-based battery electrolyte is obtained by mixing the matrix electrolyte and the hydroxylated zwitterionic additive.

[0037] The present invention does not impose any special limitations on the mixing of zinc sulfate and water, or on the mixing of the matrix electrolyte and the hydroxylated zwitterionic additive; any process known to those skilled in the art can be used.

[0038] In this invention, the zinc-based battery electrolyte is preferably used in an aqueous zinc-based battery; the aqueous zinc-based battery is preferably a Zn||Zn symmetric battery or a zinc-iodine full battery.

[0039] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0040] The raw materials and sources used in the following examples are: triethanolamine (99%, Aladdin), 1,3-propanesulfonyl lactone (99%, Aladdin), and ethyl acetate (analytical grade). Electrolyte raw materials: ZnSO4·7H2O (99.995%, Aladdin), deionized water; Auxiliary materials: zinc foil (100 μm), copper foil (20 μm), glass fiber diaphragm (GF / C, Whatman), Ketjen black (Kelode, EC-300J), carbon nanotubes (XFM13, Xianfeng Nano), PTFE dispersion (Kelode, 60wt%). Example 1 14.9 g of triethanolamine and 12.2 g of 1,3-propylsulfonyl lactone were added to 50 mL of ethyl acetate and stirred at 40 °C for 3 days. The white precipitate was collected by filtration, washed three times with ethyl acetate, and dried under vacuum to obtain 3-(tris(2-hydroxyethyl)ammonium)propane-1-sulfonate (HPS). In a 100 mL volumetric flask, ZnSO4·7H2O was dissolved in deionized water to obtain a zinc sulfate-based electrolyte with a concentration of 2 mol / L. HPS was added to the zinc sulfate-based electrolyte and stirred until completely dissolved to obtain a zinc-based battery electrolyte (the concentration of HPS in the zinc-based battery electrolyte was 1 mmol / L). Figure 3 For the HPS 1 H NMR spectrum, test results are as follows: 1H NMR (500M, D2O) δ (ppm) =3.99 (p, 6H, -CH2OH), 3.63 (t, 6H, -CH2CH2OH), 3.60 (m, 2H, -CH2CH2CH2S-), 2.90 (t, 2H, -CH2CH2CH2S-), 2.18 (p, 2H, -CH2CH2CH2S-); Figure 4 The MALDI-TOF plot of the HPS shows that the actual molecular weight of the HPS is 272.2 (HPS + H+). + ); Zn||Zn symmetric cell: 100μm thick zinc foil electrode, GF / C separator, and zinc-based battery electrolyte; The Zn||Zn symmetric cell was tested under the following conditions: 1 mA cm⁻¹ -2 1 mA·h·cm -2 Long-cycle testing at room temperature; Figure 5 The cycle stability curve of the Zn||Zn symmetric cell is given by... Figure 5 It can be seen that the cycle life of the Zn||Zn symmetric cell exceeds 5000h, and the polarization voltage is stable at 26±3mV during the cycle.

[0041] Example 2 Referring to Example 1, the difference is that the concentration of HPS in the zinc-based battery electrolyte is 50 mmol / L; Zn||Zn symmetric cell: 100μm thick zinc foil electrode, GF / C separator, and zinc-based battery electrolyte; The Zn||Zn symmetric cell was tested under the following conditions: 1 mA cm⁻¹ -2 1 mA·h·cm -2 Long-cycle testing at room temperature; Figure 6 The cycle stability curve of the Zn||Zn symmetric cell is given by... Figure 6 It can be seen that the cycle life of the Zn||Zn symmetric cell exceeds 8000h, and the polarization voltage is stable at 29±2mV during the cycle.

[0042] Example 3 Referring to Example 1, the difference is that the concentration of HPS in the zinc-based battery electrolyte is 100 mmol / L; Zn||Zn symmetric cell: 100μm thick zinc foil electrode, GF / C separator, and zinc-based battery electrolyte; The Zn||Zn symmetric cell was tested under the following conditions: 1 mA cm⁻¹-2 1 mA·h·cm -2 Long-cycle testing at room temperature; Figure 7 The cycle stability curve of the Zn||Zn symmetric cell is given by... Figure 7 It can be seen that the cycle life of the Zn||Zn symmetric cell exceeds 6000h, and the polarization voltage remains stable at 33±3mV during the cycle.

[0043] Comparative Example 1 Electrolyte: 2 mol / L zinc sulfate solution; Zn||Zn symmetric cell: 100μm thick zinc foil electrode, GF / C separator, and zinc sulfate solution; The Zn||Zn symmetric cell was tested under the following conditions: 1 mA cm⁻¹ -2 1 mA·h·cm -2 Long-cycle testing at room temperature; Figure 8 The cycle stability curve of the Zn||Zn symmetric cell is given by... Figure 8 It can be seen that the Zn||Zn symmetric cell failed within 200 hours, ultimately due to zinc dendrite short circuit, leading to cell damage. The main reason is that the zinc sulfate solution cannot suppress zinc dendrites and side reactions, resulting in extremely poor cycle stability. After further investigation... Figures 5-6 The comparison shows that the addition of HPS can improve the performance of Zn||Zn symmetric cells by orders of magnitude.

[0044] Comparative Example 2 Electrolyte: A 50 mmol / L PPS solution; the structural formula of the PPS in the PPS solution is: ; Zn||Zn symmetric cell: 100μm thick zinc foil electrode, GF / C separator, and PPS solution; The Zn||Zn symmetric cell was tested under the following conditions: 1 mA cm⁻¹ -2 1 mA·h·cm -2 Long-cycle testing at room temperature; Figure 13 The cycle stability curve of the Zn||Zn symmetric cell is given by... Figure 13 It can be seen that the cycle life of the Zn||Zn symmetric cell is approximately 2800 h, significantly lower than that of Example 2, while the polarization voltage is 45 ± 4 mV, higher than that of Example 2. The main reason is that PPS does not contain hydroxyl groups and lacks the ability to react with Zn. 2+ The synergistic effect of polyiodides cannot effectively reconstruct Zn. 2+Due to its solvated structure and interfacial hydrogen bond network, the HPS exhibits inferior cycling stability and side reaction suppression compared to HPS. Therefore, the hydroxyl groups in the HPS molecule are crucial for achieving synergistic regulation of the multiphase interface, and their combination with the zwitterionic framework is the core innovation of this invention, superior to existing zwitterionic additives.

[0045] Test case 1) Preparation of zinc-iodine full cells: Cathode preparation: Ketjen black, carbon nanotubes, and PTFE were mixed in a mass ratio of 8:1:1. 0.45 g of the mixture was pressed onto a titanium mesh (6.5 cm × 6.5 cm), and then 5 mL of iodine-ethanol solution (iodine concentration 50 mg / mL) was added dropwise. The mixture was dried for 24 h to obtain a cathode (iodine loading 4.6 mg / cm²). -2 ); Assembly of zinc-iodine full cells: Using CR2032 button cells (or pouch cells), zinc anode, separator (specifically GF / C type), zinc-based battery electrolyte as described in Example 2 or zinc sulfate solution as described in Comparative Example 1 as electrolyte and cathode are assembled in sequence; The zinc-iodine full cell was tested under the following conditions: voltage window 0.3–1.8 V, and charge / discharge current density 10 A·g. -1 ; Figure 9 The cycling stability curve of the zinc-iodine full cell assembled with the zinc sulfate solution described in Comparative Example 1 is obtained from... Figure 9 It is known that the zinc-iodine full battery will short-circuit after running for nearly 8,000 cycles; Figure 10 The cycling stability curve of the zinc-iodine full cell assembled with the zinc-based battery electrolyte described in Example 2 is obtained from... Figure 10 It can be seen that the zinc-iodine full cell has undergone more than 40,000 cycles with a decay rate of 0.00013% of initial capacity per cycle; the average coulombic efficiency is 99.8%. 2) Add 1 mmol / L dilute hydrochloric acid to the zinc-based battery electrolyte of Example 2 and the zinc sulfate solution of Comparative Example 1 respectively, and test their pH buffering behavior; at the same time, test the pH value of zinc-based battery electrolytes containing different concentrations of HPS. Figure 11 The pH buffering behavior of the zinc-based battery electrolyte described in Example 2 (corresponding to the solid sphere HPS) and the zinc sulfate solution described in Comparative Example 1 (corresponding to the solid sphere Bare) during dilute hydrochloric acid titration, as well as the pH values ​​of zinc-based battery electrolytes containing different concentrations of HPS (corresponding to the hollow spheres), were determined by... Figure 11It can be seen that, compared with the zinc sulfate solution in Comparative Example 1, the zinc-based battery electrolyte described in Example 2 shows a smaller pH change with the addition of dilute hydrochloric acid, indicating that HPS has a pH buffering effect; and as HPS increases, the zinc-based battery electrolyte containing HPS gradually turns towards neutral, indicating that HPS can inhibit hydrolysis; thus, HPS has the function of a buffer, which can regulate the pH change near the electrode in the battery, thereby reducing side reactions. Linear scan voltammetry tests were performed on the zinc-iodine full cell assembled with the zinc sulfate solution described in Comparative Example 1 and the zinc-iodine full cell assembled with the zinc-based battery electrolyte described in Example 2. The test conditions were a scan rate of 1 mV / s. Figure 12 Linear sweep voltammetry curves (where HER is the hydrogen evolution reaction and OER is the oxygen evolution reaction) of the zinc-iodine full cell assembled with the zinc sulfate solution described in Comparative Example 1 (corresponding to Bare) and the zinc-iodine full cell assembled with the zinc-based battery electrolyte described in Example 2 (corresponding to HPS) are obtained from... Figure 12 It is known that HPS can suppress hydrogen evolution and oxygen evolution reactions in batteries.

[0046] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A hydroxylated zwitterionic additive for zinc-based battery electrolytes, characterized in that, It has the structure shown in Equation 1: Formula 1; R1, R2, and R3 are all alkyl groups, and the alkyl groups include hydroxyl groups.

2. The hydroxylated zwitterionic additive as described in claim 1, characterized in that, The hydroxyl group includes terminal hydroxyl groups.

3. The hydroxylated zwitterionic additive as described in claim 1 or 2, characterized in that, The alkyl group has 1 to 5 carbon atoms.

4. The hydroxylated zwitterionic additive as described in claim 3, characterized in that, R1, R2 and R3 are all hydroxyethyl.

5. The method for preparing the hydroxylated zwitterionic additive according to any one of claims 1 to 4, characterized in that, Includes the following steps: A compound having the structure shown in Formula 2, 1,3-propylsulfonate lactone, and an organic solvent were mixed and subjected to an affinity ring-opening addition reaction to obtain the hydroxylated zwitterionic additive. Formula 2.

6. The preparation method according to claim 5, characterized in that, The molar ratio of the compound having the structure shown in Formula 2 to 1,3-propylsulfonate lactone is 1:(1~6).

7. The manufacturing method as described in claim 5, characterized in that, The nucleophilic ring-opening addition reaction was carried out at a temperature of 40°C for 72 hours. The nucleophilic ring-opening addition reaction was carried out under stirring.

8. A zinc-based battery electrolyte, characterized in that, Including zinc sulfate and hydroxylated zwitterionic additives; The hydroxylated zwitterionic additive is the hydroxylated zwitterionic additive according to any one of claims 1 to 4 or the hydroxylated zwitterionic additive prepared by the preparation method according to any one of claims 5 to 7.

9. The zinc-based battery electrolyte as described in claim 8, characterized in that, The concentration of zinc sulfate in the zinc-based battery electrolyte is 0.5~3 mol / L.

10. The zinc-based battery electrolyte as described in claim 8, characterized in that, The concentration of the hydroxylated zwitterionic additive in the zinc-based battery electrolyte is 0.5~500 mmol / L.

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