Aqueous zinc ion battery electrolyte additive, electrolyte, preparation method of electrolyte and battery

Abstract

The invention discloses an aqueous zinc ion battery electrolyte additive, an electrolyte, a preparation method of the electrolyte and a battery, and belongs to the technical field of zinc ion batteries. The additive is any one of tin tetrachloride, tin tetraiodide, indium chloride or indium iodide, and the concentration of the additive in the electrolyte is 1-20 mmol / L. The electrolyte comprises an aqueous zinc ion battery electrolyte additive, an electrolyte solvent and an electrolyte, the electrolyte solvent is an aqueous solution of isopropanol with the volume fraction of 50%; the electrolyte is one or more of zinc sulfate, zinc chloride, zinc perchlorate, zinc acetate or zinc trifluoromethanesulfonate, and the concentration of the electrolyte in the electrolyte solution is 0.5-5 mol / L. According to the zinc ion battery electrolyte additive disclosed by the invention, a metal layer can be formed on the surface of a zinc negative electrode by adding the zinc-philic compound tin tetrachloride and the like, further growth of dendritic crystals can be effectively inhibited, the flatness of the surface of the electrode is maintained, and a battery containing the electrolyte additive has good cycle stability.

Description

Technical Field

[0001] This invention belongs to the field of zinc-ion battery technology, and relates to an additive for an aqueous zinc-ion battery electrolyte, an electrolyte, a method for preparing the electrolyte, and a battery. Background Technology

[0002] Aqueous zinc-ion batteries are considered promising contenders for next-generation large-scale energy storage due to their inherent high safety, low cost, high theoretical capacity zinc anode material, and environmental friendliness. Despite their promising prospects, the commercialization of zinc-ion batteries still faces a series of severe challenges, mainly concentrated on the zinc anode: (1) During charging, uneven deposition of zinc ions on the anode surface can easily lead to the growth of zinc dendrites, which may eventually damage the integrity of the separator and cause a short circuit in the battery. (2) Since the theoretical decomposition voltage of pure water is only 1.23V, during charging and discharging, especially at the zinc anode interface, water is easily decomposed to generate hydrogen gas, causing the battery to expand and ultimately affecting battery performance and safety. (3) The relatively active chemical properties of metallic zinc can induce corrosion of the zinc anode and the generation of irreversible byproducts, thereby significantly reducing the battery life.

[0003] To address these challenges, researchers have proposed various strategies, including electrode structure design, construction of solid electrolyte interfacial films, and the regulation of solvation structures using electrolyte additives. Among these strategies, directly adding electrolyte additives to optimize battery performance is an economical and efficient method. However, current electrolyte additives do not form stable interfacial layers at high current densities, and their dendrite suppression effect is still insufficient.

[0004] Therefore, how to develop an additive for an aqueous zinc-ion battery electrolyte, an electrolyte, its preparation method, and a battery is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] In view of this, the present invention provides an additive for an aqueous zinc-ion battery electrolyte, an electrolyte, a method for preparing the electrolyte, and a battery thereof.

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

[0007] An additive for an aqueous zinc-ion battery electrolyte, wherein the additive is any one of tin tetrachloride, tin tetraiodide, indium chloride, or indium iodide, and the concentration of the additive in the electrolyte is 1-20 mmol / L.

[0008] The present invention also provides an aqueous zinc-ion battery electrolyte, comprising: the aqueous zinc-ion battery electrolyte additive, an electrolyte solvent, and an electrolyte;

[0009] The electrolyte solvent is an aqueous solution of isopropanol with a volume fraction of 50%;

[0010] The electrolyte is one or more of zinc sulfate, zinc chloride, zinc perchlorate, zinc acetate, or zinc trifluoromethanesulfonate, and the concentration of the electrolyte in the electrolyte solution is 0.5-5 mol / L.

[0011] This invention also provides a method for preparing an aqueous zinc-ion battery electrolyte, comprising the following steps:

[0012] (1) Weigh each raw material according to the aqueous zinc-ion battery electrolyte;

[0013] (2) Add the electrolyte and aqueous zinc-ion battery electrolyte additive to the electrolyte solvent and sonicate it to completely dissolve it to obtain the aqueous zinc-ion battery electrolyte.

[0014] Furthermore, the ultrasonic processing power is 200W, and the ultrasonic processing time is 5 minutes.

[0015] The present invention also provides an aqueous zinc-ion battery, the aqueous zinc-ion battery comprising: a positive electrode, a negative electrode, a separator, and an aqueous zinc-ion battery electrolyte.

[0016] Furthermore, the positive electrode is made of any one of Zn, Cu, or V2O5, the negative electrode is made of Zn, and the separator is a glass fiber separator or a polypropylene fiber separator.

[0017] The beneficial effect of this invention is that the oxygen-containing groups in the solvent can react with Zn. 2+ The coordination of the electrolyte partially or completely replaces water molecules in the solvated sheath, avoiding adverse reactions caused by water molecules at the interface. This application effectively improves the cycle life of aqueous zinc-ion batteries at high current densities by flexibly combining the advantages of different electrolyte additives. The addition of tin tetrachloride, tin tetraiodide, indium chloride, or indium iodide can effectively induce uniform deposition of zinc ions and suppress side reactions at the negative electrode interface, thereby extending the cycle life of aqueous zinc-ion batteries at high current densities.

[0018] The zinc-ion battery electrolyte of this invention contains 50% isopropanol as a solvent, which can compete with water molecules for the extrusion of Zn. 2+ In the solvated sheath, some water molecules are replaced, thereby inhibiting water decomposition to produce hydrogen and side reactions, thus extending the battery cycle life.

[0019] The zinc-ion battery electrolyte additive of the present invention, which is a zinc-loving compound tin tetrachloride, tin tetraiodide, indium chloride or indium iodide, can form a metal layer on the surface of the zinc negative electrode, effectively inhibiting further dendrite growth and maintaining the flatness of the electrode surface. The battery containing this electrolyte additive has good cycle stability. Attached Figure Description

[0020] Figure 1 The symmetrical cells assembled in Examples 1-3 were tested at 10 mA cm⁻¹. -2 Current density and 10mAh cm -2 The results of constant current charge-discharge test under the specified capacity conditions are shown in the figure.

[0021] Figure 2 The symmetrical cells assembled in Example 2 and Comparative Examples 1-2 were tested at 10 mA cm⁻¹. -2 Current density and 10mAhcm -2 The results of constant current charge-discharge test under the specified capacity conditions are shown in the figure.

[0022] Figure 3 These are in-situ optical microscope images of the deposition behavior on the electrode surface in the electrolyte systems of Example 2 and Comparative Example 1.

[0023] Figure 4 Under the electrolyte systems prepared in Example 2 and Comparative Example 1, 5 mA cm -2 Current density and 5mAh cm -2 Scanning electron microscope images after 50 cycles at the volume density, where Figure a is Comparative Example 1 and Figure b is Example 2.

[0024] Figure 5 To test the zinc-ion battery under the electrolyte systems prepared in Example 2 and Comparative Example 1, the test was conducted at 10 mA cm⁻¹. -2 Current density and 10mAh cm -2 XRD pattern of the products formed on the surface of the zinc anode after 50 cycles at capacity density. Detailed Implementation

[0025] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] Example 1

[0027] A method for preparing an aqueous zinc-ion battery electrolyte includes the following steps:

[0028] (1) Weigh out 1.75 mg of tin tetrachloride additive, 3.635 g of zinc trifluoromethanesulfonate (Zn(OTf)2) electrolyte, and 5 mL of isopropanol aqueous solution with a volume fraction of 50% for electrolyte solvent;

[0029] (2) Add the electrolyte and additives to the electrolyte solvent and sonicate for 5 minutes to completely dissolve them. The sonic power is 200W. Aqueous zinc-ion battery electrolyte is obtained. The concentration of electrolyte in the electrolyte is 2 mol / L and the concentration of additive in the electrolyte is 1 mmol / L.

[0030] The aqueous zinc-ion battery includes: a positive electrode, a negative electrode, a separator, and an aqueous zinc-ion battery electrolyte. The positive electrode is made of Zn, the negative electrode is made of Zn, and the separator is a glass fiber separator with a diameter of 19mm.

[0031] Clean zinc foil with a thickness of 100 μm was selected and cut into zinc foil discs with a diameter of 12 mm as electrodes for symmetrical cells, and assembled into Zn / / Zn button cells.

[0032] Example 2

[0033] A method for preparing an aqueous zinc-ion battery electrolyte includes the following steps:

[0034] (1) Weigh out 17.5 mg of tin tetrachloride additive, 3.635 g of zinc trifluoromethanesulfonate electrolyte, and 5 mL of an aqueous solution of isopropanol with a volume fraction of 50% for electrolyte solvent.

[0035] (2) Add the electrolyte and additives to the electrolyte solvent and sonicate for 5 minutes to completely dissolve them. The sonic power is 200W. Aqueous zinc-ion battery electrolyte is obtained. The concentration of electrolyte in the electrolyte is 2mol / L and the concentration of additive in the electrolyte is 10mmol / L.

[0036] The aqueous zinc-ion battery includes: a positive electrode, a negative electrode, a separator, and an aqueous zinc-ion battery electrolyte. The positive electrode is made of Zn, the negative electrode is made of Zn, and the separator is a glass fiber separator with a diameter of 19mm.

[0037] Clean zinc foil with a thickness of 100 μm was selected and cut into zinc foil discs with a diameter of 12 mm as electrodes for symmetrical cells, and assembled into Zn / / Zn button cells.

[0038] Example 3

[0039] A method for preparing an aqueous zinc-ion battery electrolyte includes the following steps:

[0040] (1) Weigh out 35.0 mg of tin tetrachloride additive, 3.635 g of zinc trifluoromethanesulfonate electrolyte, and 5 mL of an aqueous solution of isopropanol with a volume fraction of 50% for electrolyte solvent;

[0041] (2) Add the electrolyte and additives to the electrolyte solvent and sonicate for 5 minutes to completely dissolve them. The sonic power is 200W. Aqueous zinc-ion battery electrolyte is obtained. The concentration of electrolyte in the electrolyte is 2mol / L and the concentration of additive in the electrolyte is 20mmol / L.

[0042] The aqueous zinc-ion battery includes: a positive electrode, a negative electrode, a separator, and an aqueous zinc-ion battery electrolyte. The positive electrode is made of Zn, the negative electrode is made of Zn, and the separator is a glass fiber separator with a diameter of 19mm.

[0043] Clean zinc foil with a thickness of 100 μm was selected and cut into zinc foil discs with a diameter of 12 mm as electrodes for symmetrical cells, and assembled into Zn / / Zn button cells.

[0044] Example 4

[0045] A method for preparing an aqueous zinc-ion battery electrolyte includes the following steps:

[0046] (1) Weigh out 31.3 mg of tin tetraiodide additive, 3.635 g of zinc trifluoromethanesulfonate electrolyte, and 5 mL of an aqueous solution of isopropanol with a volume fraction of 50% for electrolyte solvent.

[0047] (2) Add the electrolyte and additives to the electrolyte solvent and sonicate for 5 minutes to completely dissolve them. The sonic power is 200W. Aqueous zinc-ion battery electrolyte is obtained. The concentration of electrolyte in the electrolyte is 2mol / L and the concentration of additive in the electrolyte is 10mmol / L.

[0048] The aqueous zinc-ion battery includes: a positive electrode, a negative electrode, a separator, and an aqueous zinc-ion battery electrolyte. The positive electrode is made of Zn, the negative electrode is made of Zn, and the separator is a glass fiber separator with a diameter of 19mm.

[0049] Clean zinc foil with a thickness of 100 μm was selected and cut into zinc foil discs with a diameter of 12 mm as electrodes for symmetrical cells, and assembled into Zn / / Zn button cells.

[0050] Example 5

[0051] A method for preparing an aqueous zinc-ion battery electrolyte includes the following steps:

[0052] (1) Weigh out 11.1 mg of indium chloride additive, 3.635 g of zinc trifluoromethanesulfonate electrolyte, and 5 mL of an aqueous solution of isopropanol with a volume fraction of 50% for electrolyte solvent;

[0053] (2) Add the electrolyte and additives to the electrolyte solvent and sonicate for 5 minutes to completely dissolve them. The sonic power is 200W. Aqueous zinc-ion battery electrolyte is obtained. The concentration of electrolyte in the electrolyte is 2mol / L and the concentration of additive in the electrolyte is 10mmol / L.

[0054] The aqueous zinc-ion battery includes: a positive electrode, a negative electrode, a separator, and an aqueous zinc-ion battery electrolyte. The positive electrode is made of Zn, the negative electrode is made of Zn, and the separator is a glass fiber separator with a diameter of 19mm.

[0055] Clean zinc foil with a thickness of 100 μm was selected and cut into zinc foil discs with a diameter of 12 mm as electrodes for symmetrical cells, and assembled into Zn / / Zn button cells.

[0056] Example 6

[0057] A method for preparing an aqueous zinc-ion battery electrolyte includes the following steps:

[0058] (1) Weigh out 24.8 mg of indium iodide additive, 3.635 g of zinc trifluoromethanesulfonate electrolyte, and 5 mL of an aqueous solution of isopropanol with a volume fraction of 50% for electrolyte solvent;

[0059] (2) Add the electrolyte and additives to the electrolyte solvent and sonicate for 5 minutes to completely dissolve them. The sonic power is 200W. Aqueous zinc-ion battery electrolyte is obtained. The concentration of electrolyte in the electrolyte is 2mol / L and the concentration of additive in the electrolyte is 10mmol / L.

[0060] The aqueous zinc-ion battery includes: a positive electrode, a negative electrode, a separator, and an aqueous zinc-ion battery electrolyte. The positive electrode is made of Zn, the negative electrode is made of Zn, and the separator is a glass fiber separator with a diameter of 19mm.

[0061] Clean zinc foil with a thickness of 100 μm was selected and cut into zinc foil discs with a diameter of 12 mm as electrodes for symmetrical cells, and assembled into Zn / / Zn button cells.

[0062] Comparative Example 1

[0063] A method for preparing an aqueous zinc-ion battery electrolyte includes the following steps:

[0064] (1) Weigh 3.635g of zinc trifluoromethanesulfonate as an additive electrolyte and 5mL of deionized water as an electrolyte solvent;

[0065] (2) Add the electrolyte to the electrolyte solvent and sonicate it for 5 minutes to completely dissolve it. The sonic power is 200W. The aqueous zinc-ion battery electrolyte is obtained with an electrolyte concentration of 2mol / L.

[0066] The aqueous zinc-ion battery includes: a positive electrode, a negative electrode, a separator, and an aqueous zinc-ion battery electrolyte. The positive electrode is made of Zn, the negative electrode is made of Zn, and the separator is a glass fiber separator with a diameter of 19mm.

[0067] Clean zinc foil with a thickness of 100 μm was selected and cut into zinc foil discs with a diameter of 12 mm as electrodes for symmetrical cells, and assembled into Zn / / Zn button cells.

[0068] Comparative Example 2

[0069] A method for preparing an aqueous zinc-ion battery electrolyte includes the following steps:

[0070] (1) Weigh 3.635 g of zinc trifluoromethanesulfonate as an additive electrolyte and 5 mL of isopropanol solution with a volume fraction of 50% as an electrolyte solvent;

[0071] (2) Add the electrolyte to the electrolyte solvent and sonicate it for 5 minutes to completely dissolve it. The sonic power is 200W. The aqueous zinc-ion battery electrolyte is obtained with an electrolyte concentration of 2mol / L.

[0072] The aqueous zinc-ion battery includes: a positive electrode, a negative electrode, a separator, and an aqueous zinc-ion battery electrolyte. The positive electrode is made of Zn, the negative electrode is made of Zn, and the separator is a glass fiber separator with a diameter of 19mm.

[0073] Clean zinc foil with a thickness of 100 μm was selected and cut into zinc foil discs with a diameter of 12 mm as electrodes for symmetrical cells, and assembled into Zn / / Zn button cells.

[0074] like Figure 1 As shown: Examples 1, 2, and 3 added different concentrations of tin tetrachloride to Comparative Example 2. The assembled symmetrical cells operated at 10 mA cm⁻¹. -2 Current density and 10mAh cm -2 Under the specified capacity conditions, it underwent constant current charge-discharge testing. (By...) Figure 1 It can be seen that the symmetrical battery in Example 2 can be stably cycled for more than 1000 hours at high current density without short circuits or potential fluctuations, indicating that the side reactions are effectively suppressed and the interface is stable. When the electrolyte contains 1 mmol / L tin tetrachloride, the polarization is slightly larger than that at 10 mmol / L, and the energy efficiency is reduced. When 20 mmol / L tin tetrachloride is added, the polarization gradually increases after 300 hours of stable cycling and obvious potential fluctuations appear.

[0075] like Figure 2As shown: Example 2 added 10 mmol / L tin tetrachloride to the basic structure of Comparative Example 2. As can be seen from the figure, the symmetrical cell of Example 2 exhibits less polarization than the symmetrical cell of Comparative Example 2, and can cycle stably for over 1000 hours at high current density, indicating that the interface stability is further improved and the energy efficiency is higher.

[0076] like Figure 3 As shown: Zn observed using an optical microscope 2+ The deposition behavior on the electrode surface in the electrolyte systems of Example 2 and Comparative Example 1, at 10 mA cm⁻¹ -2 At a current density of 10 min, images were taken every 10 min. It was clearly observed that in the system of Example 2, the growth of zinc dendrites was effectively suppressed, while the dendrite growth in Comparative Example 1 was obvious.

[0077] like Figure 4 As shown: The zinc-ion battery, in the electrolyte systems prepared in Example 2 and Comparative Example 1, achieved a 5 mA cm⁻¹ amperage. -2 Current density and 5mAh cm -2 Scanning electron microscope image after 50 cycles at capacity density. After charge-discharge cycles in a 2 mol / L Zn(OTf)₂ electrolyte, as shown... Figure 4 As shown in Figure a, dendrites grow on the surface of the zinc anode, making the surface rough and the deposited particles larger, such as... Figure 4 As shown in Figure b, after electrolyte cycling in Example 2, the surface smoothness of the zinc anode was greatly improved, and the formation and growth of dendrites were significantly inhibited. This indicates that the appropriate addition of tin tetrachloride can effectively inhibit dendrite growth.

[0078] like Figure 5 As shown: In the electrolyte systems prepared in Example 2 and Comparative Example 1, the zinc-ion battery was subjected to a 10 mA cm⁻¹ test. -2 Current density and 10mAh cm -2 XRD patterns of the products formed on the zinc anode surface after 50 cycles at capacity density show that the byproducts on the zinc anode surface are significant in pure Zn(OTf)₂ electrolyte. After adding tin tetrachloride additive, the byproduct signal on the zinc anode surface disappears significantly. XRD further confirms that the additive can effectively inhibit the side reactions at the zinc anode interface.

[0079] The description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An aqueous zinc-ion battery electrolyte additive, characterized in that, The additive is any one of tin tetrachloride, tin tetraiodide, indium chloride or indium iodide, and the concentration of the additive in the electrolyte is 1-20 mmol / L.

2. An aqueous zinc-ion battery electrolyte, characterized in that, The application relates to a water-based zinc ion battery electrolyte additive, an electrolyte solvent and an electrolyte. The electrolyte solvent is a 50% (volume fraction) isopropyl alcohol aqueous solution. The electrolyte is one or more of zinc sulfate, zinc chloride, zinc perchlorate, zinc acetate or zinc trifluoromethyl sulfonate, and the concentration of the electrolyte in the electrolyte is 0.5-5 mol / L. The application further relates to a preparation method of the water-based zinc ion battery electrolyte, which comprises the following steps:

3. A method for preparing an aqueous zinc-ion battery electrolyte, characterized in that, (1) weighing each raw material according to the water-based zinc ion battery electrolyte in claim 2; (2) adding the electrolyte and the water-based zinc ion battery electrolyte additive into the electrolyte solvent, and ultrasonically treating to completely dissolve the electrolyte and the water-based zinc ion battery electrolyte additive, so as to obtain the water-based zinc ion battery electrolyte. The ultrasonic treatment power is 200 W, and the ultrasonic treatment time is 5 min.

4. The method according to claim 3, characterized in that, The water-based zinc ion battery comprises a positive electrode, a negative electrode, a diaphragm and the water-based zinc ion battery electrolyte in claim 2.

5. An aqueous zinc-ion battery, characterized in that, The material of the positive electrode is any one of Zn, Cu or V2O5, the material of the negative electrode is Zn, and the diaphragm is a glass fiber diaphragm or a polypropylene fiber diaphragm.

6. The aqueous zinc ion battery of claim 5, wherein, ​

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