Aqueous zinc ion battery electrolyte containing hydroxyl-containing quaternary ammonium salt and methyl sulfate bifunctional additive, and preparation method and application thereof

Abstract

This invention provides an aqueous zinc-ion battery electrolyte containing a bifunctional additive of hydroxyl quaternary ammonium salt and methyl sulfate, its preparation method, and its application. The electrolyte is composed of soluble zinc salt, a bifunctional additive containing hydroxyl quaternary ammonium salt and methyl sulfate, and chromatographic water. By using the bifunctional additive containing hydroxyl quaternary ammonium salt and methyl sulfate to modify the traditional aqueous zinc-ion battery electrolyte, the zinc anode is protected, and the cycle life of the zinc anode under high utilization efficiency conditions is significantly improved. The hydroxyl groups in the hydroxyl quaternary ammonium salt additive can form hydrogen bonds with water molecules in the zinc ion solvation shell. At the same time, the quaternary ammonium salt has strong electronegativity to constrain the surrounding water molecules, inhibiting water molecule activity and reducing the occurrence of hydrogen evolution reaction. The methyl sulfate additive can be adsorbed on the surface of the zinc anode, inducing selective deposition of Zn along the (002) crystal plane and inhibiting dendrite formation. The two additives, hydroxyl quaternary ammonium salt and methyl sulfate, work synergistically to effectively improve the utilization efficiency of the zinc anode and the cycle life of the aqueous zinc-ion battery.

Description

Technical Field

[0001] This invention belongs to the field of battery technology, specifically relating to an aqueous zinc-ion battery electrolyte containing bifunctional additives of hydroxyl quaternary ammonium salt and methyl sulfate, which can alleviate dendrite growth, inhibit hydrogen evolution reaction and improve the utilization efficiency of zinc anode, as well as its preparation method and application. Background Technology

[0002] In today's society, energy demand has become a significant social issue, and batteries play a crucial role in this. Lithium-ion batteries are currently the most widely used type of battery, effectively alleviating societal capacity anxiety. However, because lithium-ion batteries contain a large amount of flammable organic electrolyte, they have encountered bottlenecks in terms of battery safety and energy density. Against this backdrop, aqueous zinc-ion batteries have emerged due to their advantages such as safety, high capacity, low cost, and environmental friendliness.

[0003] In recent years, researchers have been dedicated to developing high-performance aqueous zinc-ion batteries, hoping they can challenge the dominance of lithium-ion batteries. Some forward-looking and pioneering work on aqueous zinc-ion batteries has been achieved. However, the research process has also exposed several problems, including limited discharge capacity, low operating voltage, low energy density, short cycle life, and complex energy storage mechanisms that hinder in-depth mechanistic research. Among these problems, the short cycle life and low coulombic efficiency are the most limiting factors for the practical application of aqueous zinc-ion batteries. In the current context of widespread capacity anxiety, short cycle life and low coulombic efficiency severely restrict the use of aqueous zinc-ion batteries. The root cause of these two main problems lies in the intense parasitic reaction between the zinc metal anode and the aqueous electrolyte interface during charging and discharging, which generates a large number of reaction byproducts, induces rapid dendrite growth, and punctures the separator, causing rapid and severe internal micro-short circuits in the aqueous zinc-ion battery. Therefore, solving the dendrite growth and corrosion problems of the zinc metal anode is of great significance for the practical application of aqueous zinc-ion batteries. Summary of the Invention

[0004] The purpose of this invention is to provide an aqueous zinc-ion battery electrolyte containing a bifunctional additive of hydroxyl quaternary ammonium salt and methyl sulfate, its preparation method, and its application. The electrolyte is composed of soluble zinc salt, the bifunctional additive containing hydroxyl quaternary ammonium salt and methyl sulfate, and chromatographic water. By using the bifunctional additive containing hydroxyl quaternary ammonium salt and methyl sulfate to modify the traditional aqueous zinc-ion battery electrolyte, the zinc anode is protected, and the cycle life of the zinc anode under high utilization efficiency conditions is significantly improved. The hydroxyl groups in the hydroxyl quaternary ammonium salt can form hydrogen bonds with water molecules in the solution, inhibiting water molecule activity. Simultaneously, the strong electronegativity of the quaternary ammonium salt can restrain the occurrence of hydrogen evolution reaction in the solution, improving the utilization efficiency of the zinc anode in the aqueous zinc-ion battery. The groups of methyl sulfate preferentially adsorb onto the surface of the zinc anode, inducing crystal plane deposition along the 002 direction, inhibiting dendrite growth caused by the tip effect, and improving the cycle life of the aqueous zinc-ion battery. This solves the problems of hydrogen evolution reaction and electrode corrosion occurring on the zinc anode side of aqueous zinc-ion batteries, promoting the practical application of aqueous zinc-ion batteries.

[0005] This invention discloses an aqueous zinc-ion battery electrolyte containing a bifunctional additive of hydroxyl quaternary ammonium salt and methyl sulfate. The electrolyte comprises a soluble zinc salt, a bifunctional additive containing hydroxyl quaternary ammonium salt and methyl sulfate, and chromatographic water. The soluble zinc salt is one or two of zinc sulfate, zinc chloride, zinc nitrate, zinc acetate, zinc trifluoromethanesulfonate, zinc perchlorate, zinc trifluoromethanesulfonylimide, and zinc tetrafluoroborate. The bifunctional additive containing hydroxyl quaternary ammonium salt and methyl sulfate is choline chloride and 1-butyl-3-methylimidazolium methyl sulfate, an aqueous solution of choline hydroxide and tetrabutylammonium methyl sulfate, choline chloride and tetrabutylammonium methyl sulfate, an aqueous solution of choline hydroxide and 1-butyl-3-methylimidazolium methyl sulfate, or tris(2-hydroxyethyl)methylammonium methyl sulfate. The specific operation is carried out according to the following steps: a. Add soluble zinc salt to chromatographic water to prepare an aqueous zinc salt electrolyte with a concentration of 1-4 mol / L; b. After the pH value of the aqueous zinc salt electrolyte obtained in step a stabilizes at 2.0-6.2, add a bifunctional additive containing hydroxy quaternary ammonium salt and methyl sulfate, mix well, and let stand to obtain an aqueous zinc-ion battery electrolyte with a concentration of 10-45 mmol / L containing a bifunctional additive containing hydroxy quaternary ammonium salt and methyl sulfate.

[0006] A method for preparing an aqueous zinc-ion battery electrolyte containing a bifunctional additive of hydroxyl quaternary ammonium salt and methyl sulfate, comprising the following steps: a. Add one or two of the following soluble zinc salts to the chromatographic water: zinc sulfate, zinc chloride, zinc nitrate, zinc acetate, zinc trifluoromethanesulfonate, zinc perchlorate, zinc trifluoromethanesulfonyl imide, and zinc tetrafluoroborate, to prepare an aqueous zinc salt electrolyte with a concentration of 1-4 mol / L. b. After the pH of the aqueous zinc salt electrolyte obtained in step a stabilizes at 2.5-6.2, add bifunctional additives containing hydroxy quaternary ammonium salt and methyl sulfate, namely choline chloride and 1-butyl-3-methylimidazolium methyl sulfate, choline hydroxide aqueous solution and tetrabutylammonium methyl sulfate, choline chloride and tetrabutylammonium methyl sulfate, choline hydroxide aqueous solution and 1-butyl-3-methylimidazolium methyl sulfate, and tris(2-hydroxyethyl)methylammonium methyl sulfate. After mixing evenly, let stand to obtain an aqueous zinc-ion battery electrolyte with a concentration of 10-30 mmol / L containing bifunctional additives containing hydroxy quaternary ammonium salt and methyl sulfate.

[0007] Application of the bifunctional additive aqueous zinc-ion battery electrolyte containing hydroxyl quaternary ammonium salt and methyl sulfate in the preparation of symmetrical, asymmetrical or full cells.

[0008] A symmetrical battery was obtained by assembling an aqueous zinc-ion battery electrolyte containing bifunctional additives of hydroxyl quaternary ammonium salt and methyl sulfate with commercial zinc sheets.

[0009] An asymmetric battery is assembled by combining an aqueous zinc-ion battery electrolyte containing bifunctional additives of hydroxyl quaternary ammonium salt and methyl sulfate with commercial current collectors of titanium foil, copper foil, nickel foil, stainless steel mesh, copper mesh, nickel mesh, copper foam, or nickel foam.

[0010] An aqueous zinc-ion battery was assembled using a bifunctional additive containing hydroxyl quaternary ammonium salt and methyl sulfate as the electrolyte, commercial zinc sheets as the negative electrode, and commercial positive electrodes as AC / I2, V2O5, MnO2, or VO2.

[0011] Preferably, the symmetrical battery includes a zinc foil working electrode, a zinc foil counter electrode, and a glass fiber separator.

[0012] Preferably, the asymmetric battery includes a zinc foil working electrode and a commercial current collector counter electrode.

[0013] More preferably, the commercial current collector's electrode is a copper foil electrode.

[0014] Preferably, the positive electrode materials used in the full battery include iodine positive electrode and oxide positive electrode, specifically activated carbon-supported iodine (AC / I2), manganese dioxide (MnO2), vanadium dioxide (VO2), and vanadium pentoxide (V2O5).

[0015] More preferably, the full battery includes a zinc foil negative electrode, an activated carbon-supported iodine elemental (AC / I2) positive electrode, and an aqueous zinc-ion battery electrolyte containing bifunctional additives of hydroxyl quaternary ammonium salt and methyl sulfate.

[0016] Compared with existing technologies, this invention has the following advantages: This invention introduces a bifunctional additive containing hydroxyl quaternary ammonium salt and methyl sulfate into the basic electrolyte. This additive can improve the electrolyte interface environment from multiple directions. The hydroxyl groups in the hydroxyl quaternary ammonium salt can form hydrogen bonds with water molecules in the solution, inhibiting water molecule activity. Simultaneously, the strong electronegativity of the quaternary ammonium salt can constrain the occurrence of hydrogen evolution reaction in the solution, improving the utilization efficiency of the zinc anode in aqueous zinc-ion batteries. The groups of methyl sulfate will preferentially adsorb onto the zinc anode surface, inducing crystal plane deposition along the 002 direction, inhibiting dendrite growth caused by the tip effect, and improving the cycle life of aqueous zinc-ion batteries. Furthermore, the operation process is simple and quick, the required additive content is low, and the price is inexpensive, which is conducive to commercial use.

[0017] The features of this invention are: (1) The electrolyte is modified by a bifunctional additive containing hydroxy quaternary ammonium salt and methyl sulfate. The amount of additive used is small, the preparation cost is low, the preparation method is simple, and it is suitable for large-scale production.

[0018] (2) The present invention introduces a bifunctional additive containing hydroxyl quaternary ammonium salt and methyl sulfate into the electrolyte. The cations present in the additive affect the distribution of the hydrogen bond network and inhibit the hydrogen evolution reaction. At the same time, the anions induce the selective deposition of zinc ions along the 002 crystal plane, thereby improving the utilization efficiency of the zinc anode and extending the cycle life of the aqueous zinc-ion battery. Attached Figure Description

[0019] Figure 1 The present invention provides electrolytes containing different concentrations of bifunctional additives, namely hydroxyl quaternary ammonium salt and methyl sulfate, and electrolytes without additives, at a current density of 1 mA∙cm⁻¹. -2 The depth of discharge is 1 mAh∙cm -2 Time-voltage curves of Zn||Zn symmetric cells prepared under the specified conditions; Figure 2 The present invention provides electrolytes containing different concentrations of bifunctional additives, namely hydroxyl quaternary ammonium salt and methyl sulfate, and electrolytes without additives, at a current density of 1 mA∙cm⁻¹. -2 The depth of discharge is 1 mAh∙cm -2 X-ray diffraction (XRD) pattern of byproducts on the surface of the negative electrode of a Zn||Zn symmetric cell after cycling to cell failure under the condition; Figure 3 Tafel curves are shown for the three-electrode systems prepared by the bifunctional additive containing hydroxy quaternary ammonium salt and methyl sulfate (10 mmol / L) and the electrolyte without additive. Figure 4The cycling performance curves of Zn-AC / I2 full cells prepared with the bifunctional additive containing hydroxyl quaternary ammonium salt and methyl sulfate (20 mmol / L) and the electrolyte without additive are shown below, with a ratio of 1 A∙g. -1 Discharge at current density; where Bare in the figure is an aqueous zinc sulfate solution (also known as: aqueous zinc salt electrolyte), and the zinc sulfate concentration is 2 mol / L; Sample in the figure is an aqueous zinc-ion battery electrolyte containing bifunctional additives of hydroxyl quaternary ammonium salt and methyl sulfate; Sample 1 in the figure is an aqueous zinc-ion battery electrolyte containing bifunctional additives of hydroxyl quaternary ammonium salt and methyl sulfate, and the concentration of the bifunctional additives of hydroxyl quaternary ammonium salt and methyl sulfate is 10 mmol / L; Sample 2 in the figure is an aqueous zinc-ion battery electrolyte containing bifunctional additives of hydroxyl quaternary ammonium salt and methyl sulfate, and the concentration of the bifunctional additives of hydroxyl quaternary ammonium salt and methyl sulfate is 20 mmol / L; Sample 3 in the figure is an aqueous zinc-ion battery electrolyte containing bifunctional additives of hydroxyl quaternary ammonium salt and methyl sulfate, and the concentration of the bifunctional additives of hydroxyl quaternary ammonium salt and methyl sulfate is 30 mmol / L. mmol / L; Sample 4 in the figure is an aqueous zinc-ion battery electrolyte containing a bifunctional additive of hydroxy quaternary ammonium salt and methyl sulfate, and the concentration of the bifunctional additive of hydroxy quaternary ammonium salt and methyl sulfate is 45 mmol / L. Detailed Implementation

[0020] The present invention will now be described in more detail with reference to specific embodiments and accompanying drawings to facilitate understanding of the technical solutions of the present invention. However, this description is not intended to limit the scope of protection of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Example 1

[0021] a. Add soluble zinc salt, zinc sulfate, to chromatographic water to prepare an aqueous zinc salt electrolyte with a concentration of 2 mol / L; b. After the pH value of the aqueous zinc salt electrolyte obtained in step a stabilizes at 3.5-4.5, add the bifunctional additives of hydroxy quaternary ammonium salt and methyl sulfate, namely choline chloride and 1-butyl-3-methylimidazolium methyl sulfate, mix evenly, and let stand to obtain an aqueous zinc-ion battery electrolyte with a concentration of 10 mmol / L of the bifunctional additives of hydroxy quaternary ammonium salt and methyl sulfate.

[0022] Preparation of negative electrode sheet: The zinc sheet was polished with 2000-mesh sandpaper, placed in an ethanol solution, sonicated for 5 min, and dried in an oven at 60 ℃; Preparation of electrolyte: Add 10 mmol / L of a bifunctional additive of hydroxy quaternary ammonium salt and methyl sulfate to a 2 mol / L zinc sulfate solution, and stir to mix evenly to obtain a mixed electrolyte; The battery is assembled in the following steps: negative electrode shell, negative electrode sheet, glass fiber fully wetted by mixed electrolyte, positive electrode sheet, gasket, spring sheet, and positive electrode shell.

[0023] This example demonstrates the assembly of a Zn||Zn symmetric cell using an electrolyte system with a concentration of 10-45 mmol / L, at a current density of 1 mA∙cm⁻¹. -2 The depth of discharge is 1 mAh∙cm -2 The cycle is performed under the given conditions; Figure 2 The image shown is an XRD pattern after cycling to battery failure in this embodiment, indicating that the addition of the bifunctional additive of hydroxy quaternary ammonium salt and methyl sulfate can effectively suppress the formation of byproducts. Example 2

[0024] a. Add soluble zinc salt, zinc sulfate, to chromatographic water to prepare an aqueous zinc salt electrolyte with a concentration of 2 mol / L; b. After the pH value of the aqueous zinc salt electrolyte obtained in step a stabilizes at 3.5-4.5, add the bifunctional additive of hydroxy quaternary ammonium salt and methyl sulfate, namely choline hydroxide aqueous solution and tetrabutylammonium methyl sulfate, mix evenly, and let stand to obtain an aqueous zinc-ion battery electrolyte with a concentration of 20 mmol / L of bifunctional additive of hydroxy quaternary ammonium salt and methyl sulfate.

[0025] Preparation of negative electrode sheet: The zinc sheet was polished with 2000-mesh sandpaper, placed in an ethanol solution, sonicated for 5 min, and dried in an oven at 60 ℃; Preparation of electrolyte: Add 20 mmol / L of a bifunctional additive of hydroxy quaternary ammonium salt and methyl sulfate to a 2 mol / L zinc sulfate solution, and stir to mix evenly to obtain a mixed electrolyte; The electrolyte containing the bifunctional additives of hydroxy quaternary ammonium salt and methyl sulfate, and the electrolyte without the additives obtained in this embodiment, were applied to a three-electrode system with zinc foil as the working electrode, platinum sheet as the counter electrode, and Ag / AgCl electrode (0.197V vs. SHE) as the reference electrode, at a range of -0.6 to -1.1V for 1 mV s. -1 Tafel plots were obtained by band scanning.

[0026] The results are as follows Figure 3 As shown, the corrosion current of the electrolyte decreased from 30.90 μA cm⁻¹ after the addition of the bifunctional additive of hydroxy quaternary ammonium salt and methyl sulfate. -2 Decreased to 8.155 μA cm -2This indicates that the addition of bifunctional additives of hydroxy quaternary ammonium salt and methyl sulfate effectively inhibited the corrosion of the zinc anode. Example 3

[0027] a. Add soluble zinc salt (zinc chloride) to chromatographic water to prepare an aqueous zinc salt electrolyte with a concentration of 2 mol / L; b. After the pH value of the aqueous zinc salt electrolyte obtained in step a stabilizes at 4.5-4.8, add the bifunctional additives of hydroxy quaternary ammonium salt and methyl sulfate, namely choline chloride and tetrabutylammonium methyl sulfate, mix evenly, and let stand to obtain an aqueous zinc-ion battery electrolyte with a concentration of 30 mmol / L of bifunctional additives of hydroxy quaternary ammonium salt and methyl sulfate.

[0028] Preparation of negative electrode sheet: The zinc sheet was polished with 2000-mesh sandpaper, placed in an ethanol solution, sonicated for 5 min, and dried in an oven at 60 ℃; To prepare the positive electrode, commercially available current collector copper foil was cut into circular pieces with a diameter of d=1cm, and half-cell tests were conducted. Preparation of electrolyte: Add 30 mmol / L of a bifunctional additive of hydroxy quaternary ammonium salt and methyl sulfate to a 2 mol / L zinc chloride solution, and stir to mix evenly to obtain a mixed electrolyte; The battery is assembled in the following steps: negative electrode shell, negative electrode sheet, glass fiber fully wetted by mixed electrolyte, positive electrode sheet, gasket, spring sheet, and positive electrode shell. Example 4

[0029] a. Add soluble zinc salt, zinc acetate, to chromatographic water to prepare an aqueous zinc salt electrolyte with a concentration of 4 mol / L; b. After the pH value of the aqueous zinc salt electrolyte obtained in step a stabilizes at 5.8-6.2, add the bifunctional additive of hydroxy quaternary ammonium salt and methyl sulfate, namely choline hydroxide aqueous solution and 1-butyl-3-methylimidazolium methyl sulfate, mix evenly, and let stand to obtain an aqueous zinc-ion battery electrolyte with a concentration of 45 mmol / L of bifunctional additive of hydroxy quaternary ammonium salt and methyl sulfate.

[0030] Preparation of negative electrode sheet: polish the zinc sheet with 2000-mesh sandpaper, place it in an ethanol solution, sonicate for 5 min, and dry it in an oven at 60 ℃.

[0031] To prepare the positive electrode, commercially available current collector titanium foil was cut into circular pieces with a diameter of d=1cm, and half-cell tests were conducted. Preparation of electrolyte: Add 15 mmol / L of a bifunctional additive of hydroxy quaternary ammonium salt and methyl sulfate to a 4 mol / L zinc acetate solution, stir and mix evenly to obtain a mixed electrolyte; The battery is assembled in the following steps: negative electrode shell, negative electrode sheet, glass fiber fully wetted by mixed electrolyte, positive electrode sheet, gasket, spring sheet, and positive electrode shell. Example 5

[0032] a. Add soluble zinc salt, zinc tetrafluoroborate, to chromatographic water to prepare an aqueous zinc salt electrolyte with a concentration of 2 mol / L; b. After the pH value of the aqueous zinc salt electrolyte obtained in step a stabilizes at 2.5-3.5, add tris(2-hydroxyethyl)methylammonium methyl sulfate, a bifunctional additive of hydroxy quaternary ammonium salt and methyl sulfate, mix well, and let stand to obtain an aqueous zinc-ion battery electrolyte with a concentration of 10 mmol / L of bifunctional additive of hydroxy quaternary ammonium salt and methyl sulfate.

[0033] Preparation of negative electrode sheet: The zinc sheet was polished with 2000-mesh sandpaper, placed in an ethanol solution, sonicated for 5 min, and dried in an oven at 60 ℃; To prepare the positive electrode, commercially available current collector nickel foil was cut into circular pieces with a diameter of d=1cm, and half-cell tests were conducted. Preparation of electrolyte: Add 10 mmol / L of a bifunctional additive of hydroxy quaternary ammonium salt and methyl sulfate to a 2 mol / L zinc tetrafluoroborate solution, and stir to mix evenly to obtain a mixed electrolyte; The battery is assembled in the following steps: negative electrode shell, negative electrode sheet, glass fiber fully wetted by mixed electrolyte, positive electrode sheet, gasket, spring sheet, and positive electrode shell. Example 6

[0034] a. Add soluble zinc salt, zinc trifluoromethanesulfonyl imide, to chromatographic water to prepare an aqueous zinc salt electrolyte with a concentration of 2 mol / L; b. After the pH value of the aqueous zinc salt electrolyte obtained in step a stabilizes at 2.5-3.5, add the bifunctional additives of hydroxy quaternary ammonium salt and methyl sulfate, namely choline chloride and 1-butyl-3-methylimidazolium methyl sulfate, mix evenly, and let stand to obtain an aqueous zinc-ion battery electrolyte with a concentration of 20 mmol / L of the bifunctional additives of hydroxy quaternary ammonium salt and methyl sulfate.

[0035] Preparation of negative electrode sheet: The zinc sheet was polished with 2000-mesh sandpaper, placed in an ethanol solution, sonicated for 5 min, and dried in an oven at 60 ℃; To prepare the positive electrode, commercially available stainless steel current collector mesh was cut into circular pieces with a diameter of d=1cm, and half-cell tests were conducted. Preparation of electrolyte: Add 20 mmol / L of a bifunctional additive of hydroxy quaternary ammonium salt and methyl sulfate to a 2 mol / L zinc trifluoromethanesulfonyl imide solution, and stir to mix evenly to obtain a mixed electrolyte; The battery is assembled in the following steps: negative electrode shell, negative electrode sheet, glass fiber fully wetted by mixed electrolyte, positive electrode sheet, gasket, spring sheet, and positive electrode shell. Example 7

[0036] a. Add soluble zinc salts, namely zinc sulfate and zinc perchlorate, to the chromatographic water to prepare a 3 mol / L aqueous zinc salt mixed electrolyte; b. After the pH value of the aqueous zinc salt electrolyte obtained in step a stabilizes at 2.0-3.0, add the bifunctional additive of hydroxy quaternary ammonium salt and methyl sulfate, namely choline hydroxide aqueous solution and tetrabutylammonium methyl sulfate, mix evenly, and let stand to obtain an aqueous zinc-ion battery electrolyte with a concentration of 30 mmol / L of bifunctional additive of hydroxy quaternary ammonium salt and methyl sulfate.

[0037] Preparation of negative electrode sheet: The zinc sheet was polished with 2000-mesh sandpaper, placed in an ethanol solution, sonicated for 5 min, and dried in an oven at 60 ℃; To prepare the positive electrode, commercially available current collector foamed copper was cut into circular pieces with a diameter of d=1cm and tested for half-cell. Preparation of electrolyte: Add 30 mmol / L of a bifunctional additive of hydroxy quaternary ammonium salt and methyl sulfate to a 3 mol / L aqueous zinc salt mixed electrolyte of zinc sulfate and zinc perchlorate, and stir to mix evenly to obtain a mixed electrolyte; The battery is assembled in the following steps: negative electrode shell, negative electrode sheet, glass fiber fully wetted by mixed electrolyte, positive electrode sheet, gasket, spring sheet, and positive electrode shell. Example 8

[0038] a. Add soluble zinc salt, zinc sulfate, to chromatographic water to prepare an aqueous zinc salt electrolyte with a concentration of 2 mol / L; b. After the pH value of the aqueous zinc salt electrolyte obtained in step a stabilizes at 3.5-4.5, add the bifunctional additives of hydroxy quaternary ammonium salt and methyl sulfate, namely choline chloride and tetrabutylammonium methyl sulfate, mix evenly, and let stand to obtain an aqueous zinc-ion battery electrolyte with a concentration of 45 mmol / L of the bifunctional additives of hydroxy quaternary ammonium salt and methyl sulfate.

[0039] Preparation of the positive electrode: Ketjen black, conductive carbon black (Super P), and polyvinylidene fluoride (PVDF) were mixed in a ratio of 7:2:1 and 30 drops of N-methylpyrrolidone (NMP) were added in a mortar. The mixture was then ground and coated onto graphite paper and vacuum-dried at 80℃ for 12 hours. The prepared substrate material was cut into circular pieces with a diameter of d=1cm, placed in a sample box, and an appropriate amount of iodine was added. The sample box was sealed with a sample bag and heated at 110℃ for 12 hours. The prepared samples were tested for full-cell performance. The sample prepared at 100℃ had a capacity of 110 mAh / g, and the sample prepared at 110℃ had a capacity of 130 mAh / g. Preparation of negative electrode sheet: The zinc sheet was polished with 2000-mesh sandpaper, placed in an ethanol solution, sonicated for 5 min, and dried in an oven at 60 ℃; Preparation of electrolyte: Add 45 mmol / L of a bifunctional additive of hydroxy quaternary ammonium salt and methyl sulfate to a 2 mol / L zinc sulfate solution, and stir to mix evenly to obtain a mixed electrolyte; The battery is assembled in the following steps: negative electrode shell, negative electrode sheet, glass fiber fully wetted by mixed electrolyte, positive electrode sheet, gasket, spring sheet, and positive electrode shell.

[0040] In this embodiment, the assembled Zn-AC / I2 full cell is subjected to 1 A·g -1 The cells were cycled at a current density of 88.5% and the coulombic efficiency was 88.5% after 6000 cycles, which is much higher than that of full cells with basic electrolyte. Example 9

[0041] a. Add soluble zinc salt, zinc perchlorate, to chromatographic water to prepare an aqueous zinc salt electrolyte with a concentration of 1 mol / L; b. After the pH value of the aqueous zinc salt electrolyte obtained in step a stabilizes at 5.0-5.5, add the bifunctional additive of hydroxy quaternary ammonium salt and methyl sulfate, namely choline hydroxide aqueous solution and 1-butyl-3-methylimidazolium methyl sulfate, mix evenly, and let stand to obtain an aqueous zinc-ion battery electrolyte with a concentration of 10 mmol / L of bifunctional additive of hydroxy quaternary ammonium salt and methyl sulfate.

[0042] Preparation of the positive electrode: MnO2, conductive carbon black (Super P), and polyvinylidene fluoride (PVDF) were mixed in a ratio of 7:2:1 and 30 drops of N-methylpyrrolidone (NMP) were added in a mortar. The mixture was then ground and coated onto graphite paper and vacuum dried at 80°C for 12 hours. The prepared substrate material was cut into circular pieces with a diameter of d=1cm. The prepared samples were then tested for full-cell performance. Preparation of negative electrode sheet: The zinc sheet was polished with 2000-mesh sandpaper, placed in an ethanol solution, sonicated for 5 min, and dried in an oven at 60 ℃; Preparation of electrolyte: Add 10 mmol / L of a bifunctional additive of hydroxy quaternary ammonium salt and methyl sulfate to a 1 mol / L zinc perchlorate solution, stir and mix evenly to obtain a mixed electrolyte; The battery is assembled in the following steps: negative electrode shell, negative electrode sheet, glass fiber fully wetted by mixed electrolyte, positive electrode sheet, gasket, spring sheet, and positive electrode shell.

[0043] In this embodiment, the assembled Zn-MnO2 full cell exhibits significantly better performance than the full cell with the basic electrolyte. Example 10

[0044] a. Add soluble zinc salt, zinc trifluoromethanesulfonate, to chromatographic water to prepare an aqueous zinc salt electrolyte with a concentration of 4 mol / L; b. After the pH value of the aqueous zinc salt electrolyte obtained in step a stabilizes at 4.2-5.0, add tris(2-hydroxyethyl)methylammonium methyl sulfate, a bifunctional additive of hydroxy quaternary ammonium salt and methyl sulfate, mix well, and let stand to obtain an aqueous zinc-ion battery electrolyte with a concentration of 20 mmol / L of bifunctional additive of hydroxy quaternary ammonium salt and methyl sulfate.

[0045] Preparation of the positive electrode: V2O5, conductive carbon black (Super P), and polyvinylidene fluoride (PVDF) were mixed in a ratio of 7:2:1 and 30 drops of N-methylpyrrolidone (NMP) were added in a mortar. The mixture was then ground and coated onto graphite paper and vacuum dried at 80°C for 12 hours. The prepared substrate material was cut into circular pieces with a diameter of d=1cm. The prepared samples were then tested for full-cell performance. Preparation of negative electrode sheet: The zinc sheet was polished with 2000-mesh sandpaper, placed in an ethanol solution, sonicated for 5 min, and dried in an oven at 60 ℃; Preparation of electrolyte: Add 20 mmol / L of a bifunctional additive of hydroxy quaternary ammonium salt and methyl sulfate to a 4 mol / L zinc trifluoromethanesulfonate solution, and stir to mix evenly to obtain a mixed electrolyte; The battery is assembled in the following steps: negative electrode shell, negative electrode sheet, glass fiber fully wetted by mixed electrolyte, positive electrode sheet, gasket, spring sheet, and positive electrode shell. In this embodiment, the assembled Zn-V2O5 full cell exhibits significantly better performance than the full cell with the basic electrolyte. Example 11

[0046] a. Add soluble zinc salts, namely zinc sulfate and zinc perchlorate, to chromatographic water to prepare a 3 mol / L aqueous mixed zinc salt electrolyte; b. After the pH value of the aqueous zinc salt electrolyte obtained in step a stabilizes at 2.0-3.0, add the bifunctional additives of hydroxy quaternary ammonium salt and methyl sulfate, namely choline chloride and 1-butyl-3-methylimidazolium methyl sulfate, mix evenly, and let stand to obtain an aqueous zinc-ion battery electrolyte with a concentration of 30 mmol / L of the bifunctional additives of hydroxy quaternary ammonium salt and methyl sulfate.

[0047] Preparation of the positive electrode: VO2: conductive carbon black (Super P): polyvinylidene fluoride (PVDF) was mixed in a ratio of 7:2:1 and 30 drops of N-methylpyrrolidone (NMP) were added in a mortar. The mixture was then ground and coated onto graphite paper and vacuum dried at 80℃ for 12 hours. The prepared substrate material was cut into circular pieces with a diameter of d=1cm. The prepared samples were then tested for full cell performance. Preparation of negative electrode sheet: The zinc sheet was polished with 2000-mesh sandpaper, placed in an ethanol solution, sonicated for 5 min, and dried in an oven at 60 ℃; Preparation of electrolyte: Add 30 mmol / L of a bifunctional additive of hydroxy quaternary ammonium salt and methyl sulfate to a 3 mol / L zinc sulfate and zinc perchlorate mixed solution, and stir to mix evenly to obtain a mixed electrolyte; The battery is assembled in the following steps: negative electrode shell, negative electrode sheet, glass fiber fully wetted by mixed electrolyte, positive electrode sheet, gasket, spring sheet, and positive electrode shell.

[0048] In this embodiment, the assembled Zn-VO2 full cell exhibits significantly better performance than the full cell with the basic electrolyte. Example 12

[0049] a. Add soluble zinc salt (zinc chloride) to chromatographic water to prepare an aqueous zinc salt electrolyte with a concentration of 2 mol / L; b. After the pH value of the aqueous zinc salt electrolyte obtained in step a stabilizes at 4.5-4.8, add the bifunctional additives of hydroxy quaternary ammonium salt and methyl sulfate, namely choline hydroxide aqueous solution and tetrabutylammonium methyl sulfate. After mixing evenly, let stand to obtain an aqueous zinc-ion battery electrolyte with a concentration of 45 mmol / L of the bifunctional additives of hydroxy quaternary ammonium salt and methyl sulfate.

[0050] Preparation of negative electrode sheet: The zinc sheet was polished with 2000-mesh sandpaper, placed in an ethanol solution, sonicated for 5 min, and dried in an oven at 60 ℃; The Zn||Zn symmetric cell is obtained by assembling the battery in the following steps: negative electrode shell, negative electrode sheet, glass fiber fully wetted by mixed electrolyte, positive electrode sheet, gasket, spring sheet, and positive electrode shell. Example 13

[0051] a. Add soluble zinc salt, zinc acetate, to chromatographic water to prepare an aqueous zinc salt electrolyte with a concentration of 4 mol / L; b. After the pH value of the aqueous zinc salt electrolyte obtained in step a stabilizes at 5.8-6.2, add the bifunctional additives of hydroxy quaternary ammonium salt and methyl sulfate, namely choline chloride and tetrabutylammonium methyl sulfate. After mixing evenly, let stand to obtain an aqueous zinc-ion battery electrolyte with a concentration of 10 mmol / L of the bifunctional additives of hydroxy quaternary ammonium salt and methyl sulfate.

[0052] Preparation of negative electrode sheet: The zinc sheet was polished with 2000-mesh sandpaper, placed in an ethanol solution, sonicated for 5 min, and dried in an oven at 60 ℃; The Zn||Zn symmetric cell is obtained by assembling the battery in the following steps: negative electrode shell, negative electrode sheet, glass fiber fully wetted by mixed electrolyte, positive electrode sheet, gasket, spring sheet, and positive electrode shell. Example 14

[0053] a. Add soluble zinc salt, zinc trifluoromethanesulfonate, to chromatographic water to prepare an aqueous zinc salt electrolyte with a concentration of 4 mol / L; b. After the pH value of the aqueous zinc salt electrolyte obtained in step a stabilizes at 4.2-5.0, add the bifunctional additives of hydroxy quaternary ammonium salt and methyl sulfate, namely choline hydroxide aqueous solution and 1-butyl-3-methylimidazolium methyl sulfate. After mixing evenly, let stand to obtain an aqueous zinc-ion battery electrolyte with a concentration of 20 mmol / L of the bifunctional additives of hydroxy quaternary ammonium salt and methyl sulfate.

[0054] Preparation of negative electrode sheet: The zinc sheet was polished with 2000-mesh sandpaper, placed in an ethanol solution, sonicated for 5 min, and dried in an oven at 60 ℃; The Zn||Zn symmetric cell is obtained by assembling the battery in the following steps: negative electrode shell, negative electrode sheet, glass fiber fully wetted by mixed electrolyte, positive electrode sheet, gasket, spring sheet, and positive electrode shell. Example 15

[0055] a. Add soluble zinc salt, zinc perchlorate, to chromatographic water to prepare an aqueous zinc salt electrolyte with a concentration of 1 mol / L; b. After the pH value of the aqueous zinc salt electrolyte obtained in step a stabilizes at 5.0-5.5, add tris(2-hydroxyethyl)methylammonium methyl sulfate, a bifunctional additive of hydroxy quaternary ammonium salt and methyl sulfate. After mixing evenly, let stand to obtain an aqueous zinc-ion battery electrolyte with a concentration of 30 mmol / L of bifunctional additive of hydroxy quaternary ammonium salt and methyl sulfate.

[0056] Preparation of negative electrode sheet: The zinc sheet was polished with 2000-mesh sandpaper, placed in an ethanol solution, sonicated for 5 min, and dried in an oven at 60 ℃; The Zn||Zn symmetric cell is obtained by assembling the battery in the following steps: negative electrode shell, negative electrode sheet, glass fiber fully wetted by mixed electrolyte, positive electrode sheet, gasket, spring sheet, and positive electrode shell. Example 16

[0057] a. Add soluble zinc salt, zinc trifluoromethanesulfonyl imide, to chromatographic water to prepare an aqueous zinc salt electrolyte with a concentration of 1 mol / L; b. After the pH value of the aqueous zinc salt electrolyte obtained in step a stabilizes at 2.5-3.5, add the bifunctional additives of hydroxy quaternary ammonium salt and methyl sulfate, namely choline chloride and 1-butyl-3-methylimidazolium methyl sulfate. After mixing evenly, let stand to obtain an aqueous zinc-ion battery electrolyte with a concentration of 45 mmol / L of the bifunctional additives of hydroxy quaternary ammonium salt and methyl sulfate.

[0058] Preparation of negative electrode sheet: The zinc sheet was polished with 2000-mesh sandpaper, placed in an ethanol solution, sonicated for 5 min, and dried in an oven at 60 ℃; The Zn||Zn symmetric cell is obtained by assembling the battery in the following steps: negative electrode shell, negative electrode sheet, glass fiber fully wetted by mixed electrolyte, positive electrode sheet, gasket, spring sheet, and positive electrode shell. Example 17

[0059] a. Add soluble zinc salt, zinc tetrafluoroborate, to chromatographic water to prepare an aqueous zinc salt electrolyte with a concentration of 2 mol / L; b. After the pH value of the aqueous zinc salt electrolyte obtained in step a stabilizes at 2.5-3.5, add the bifunctional additives of hydroxy quaternary ammonium salt and methyl sulfate, namely choline hydroxide aqueous solution and tetrabutylammonium methyl sulfate. After mixing evenly, let stand to obtain an aqueous zinc-ion battery electrolyte with a concentration of 10 mmol / L of the bifunctional additives of hydroxy quaternary ammonium salt and methyl sulfate.

[0060] Preparation of negative electrode sheet: The zinc sheet was polished with 2000-mesh sandpaper, placed in an ethanol solution, sonicated for 5 min, and dried in an oven at 60 ℃; The Zn||Zn symmetric cell is obtained by assembling the battery in the following steps: negative electrode shell, negative electrode sheet, glass fiber fully wetted by mixed electrolyte, positive electrode sheet, gasket, spring sheet, and positive electrode shell. Example 18

[0061] a. Add soluble zinc salts, namely zinc sulfate and zinc perchlorate, to chromatographic water to prepare an aqueous zinc salt electrolyte with a concentration of 3 mol / L; b. After the pH value of the aqueous zinc salt electrolyte obtained in step a stabilizes at 2.0-3.0, add the bifunctional additives of hydroxy quaternary ammonium salt and methyl sulfate, namely choline chloride and tetrabutylammonium methyl sulfate. After mixing evenly, let stand to obtain an aqueous zinc-ion battery electrolyte with a concentration of 20 mmol / L of the bifunctional additives of hydroxy quaternary ammonium salt and methyl sulfate.

[0062] Preparation of negative electrode sheet: The zinc sheet was polished with 2000-mesh sandpaper, placed in an ethanol solution, sonicated for 5 min, and dried in an oven at 60 ℃; The Zn||Zn symmetric cell is obtained by assembling the battery in the following steps: negative electrode shell, negative electrode sheet, glass fiber fully wetted by mixed electrolyte, positive electrode sheet, gasket, spring sheet, and positive electrode shell.

Claims

1. An aqueous zinc-ion battery electrolyte containing bifunctional additives of hydroxyl quaternary ammonium salt and methyl sulfate, characterized in that, The electrolyte consists of a soluble zinc salt, a bifunctional additive containing hydroxyl quaternary ammonium salt and methyl sulfate, and chromatographic water. The soluble zinc salt is one or two of zinc sulfate, zinc chloride, zinc nitrate, zinc acetate, zinc trifluoromethanesulfonate, zinc perchlorate, zinc trifluoromethanesulfonylimide, and zinc tetrafluoroborate. The bifunctional additive containing hydroxyl quaternary ammonium salt and methyl sulfate is choline chloride and 1-butyl-3-methylimidazolium methyl sulfate, choline hydroxide aqueous solution and tetrabutylammonium methyl sulfate, choline chloride and tetrabutylammonium methyl sulfate, choline hydroxide aqueous solution and 1-butyl-3-methylimidazolium methyl sulfate, or tris(2-hydroxyethyl)methylammonium methyl sulfate. The specific operation is carried out according to the following steps: a. Prepare an aqueous zinc salt electrolyte with a concentration of 1-4 mol / L by adding soluble zinc salt to chromatographic water; b. After the pH value of the aqueous zinc salt electrolyte obtained in step a stabilizes at 2.0-6.2, add a bifunctional additive containing hydroxy quaternary ammonium salt and methyl sulfate, mix well, and let stand to obtain an aqueous zinc-ion battery electrolyte with a concentration of 10-45 mmol / L containing a bifunctional additive containing hydroxy quaternary ammonium salt and methyl sulfate.

2. A method for preparing an aqueous zinc-ion battery electrolyte containing a bifunctional additive of hydroxyl quaternary ammonium salt and methyl sulfate, characterized in that, Follow these steps: a. Add one or two of the following soluble zinc salts to the chromatographic water: zinc sulfate, zinc chloride, zinc nitrate, zinc acetate, zinc trifluoromethanesulfonate, zinc perchlorate, zinc trifluoromethanesulfonyl imide, and zinc tetrafluoroborate, to prepare an aqueous zinc salt electrolyte with a concentration of 1-4 mol / L. b. After the pH of the aqueous zinc salt electrolyte obtained in step a stabilizes at 2.5-6.2, add bifunctional additives containing hydroxy quaternary ammonium salt and methyl sulfate, namely choline chloride and 1-butyl-3-methylimidazolium methyl sulfate, choline hydroxide aqueous solution and tetrabutylammonium methyl sulfate, choline chloride and tetrabutylammonium methyl sulfate, choline hydroxide aqueous solution and 1-butyl-3-methylimidazolium methyl sulfate, and tris(2-hydroxyethyl)methylammonium methyl sulfate. After mixing evenly, let stand to obtain an aqueous zinc-ion battery electrolyte with a concentration of 10-30 mmol / L containing bifunctional additives containing hydroxy quaternary ammonium salt and methyl sulfate.

3. The application of the bifunctional additive aqueous zinc-ion battery electrolyte containing hydroxyl quaternary ammonium salt and methyl sulfate as described in claim 1 or 2 in the preparation of symmetrical batteries, asymmetrical batteries or full batteries.

4. The application according to claim 3, characterized in that, A symmetrical battery was obtained by assembling an aqueous zinc-ion battery electrolyte containing bifunctional additives of hydroxyl quaternary ammonium salt and methyl sulfate with commercial zinc sheets.

5. The application according to claim 3, characterized in that, An asymmetric battery is assembled by combining an aqueous zinc-ion battery electrolyte containing bifunctional additives of hydroxyl quaternary ammonium salt and methyl sulfate with commercial current collectors of titanium foil, copper foil, nickel foil, stainless steel mesh, copper mesh, nickel mesh, copper foam, or nickel foam.

6. The application according to claim 3, characterized in that, An aqueous zinc-ion battery was assembled using a bifunctional additive containing hydroxyl quaternary ammonium salt and methyl sulfate as the electrolyte, commercial zinc sheets as the negative electrode, and commercial positive electrodes as AC / I2, V2O5, MnO2, or VO2.

Images