Electrolyte configured with an organic anion-enriched interface to inhibit zinc dendrites

Abstract

The present application relates to a kind of electrolyte of organic anion enrichment interface inhibition zinc dendrite, belong to the field of electrolyte modification.The present application uses a small amount of acetylsulfamethoxypyridazine (ACE) as electrolyte additive to effectively inhibit the growth of zinc dendrite and the occurrence of a variety of side reactions, the method for improving the cycle stability and life of aqueous zinc-ion battery.Specific method is: a small amount of acetylsulfamethoxypyridazine as additive is directly added to zinc sulfate electrolyte, by building an organic anion enrichment interface on the surface of zinc, realize the 4600 hours (more than 6 months) life of aqueous zinc-ion battery.The present application has far-reaching significance for the long-life application of aqueous zinc-ion battery in the future.

Description

TECHNICAL FIELD

[0001] The application relates to an electrolyte with an organic anion-rich interface for inhibiting zinc dendrites. BACKGROUND

[0002] In recent years, aqueous zinc-ion batteries have attracted much attention due to their remarkable advantages, such as high capacity, low cost, environmental friendliness and high safety. However, uncontrollable zinc dendrite growth remains a key factor limiting the lifetime of zinc-ion batteries. Specifically, the inhomogeneous Zn 2+ flux and inhomogeneous electric field distribution at the electrolyte / electrode interface can lead to the dendritic deposition of zinc. The growing zinc dendrites have a high Young's modulus, can easily penetrate the separator and connect the two electrodes to cause internal short circuits, leading to the premature failure of the battery. In addition, rampant side reactions (i.e., hydrogen evolution reaction, zinc corrosion) occur on the zinc negative electrode during electrochemical cycling, further producing undesirable by-products ((Zn(OH)2)3(ZnSO4)(H2O) X ). SUMMARY

[0003] The application aims to solve the problems of serious zinc dendrite growth and side reactions in zinc-ion batteries, and provides an electrolyte with an organic anion-rich interface for inhibiting zinc dendrites. The application effectively inhibits dendrites and side reactions in zinc-ion batteries by constructing an organic anion-rich interface, thereby greatly prolonging the cycle life of aqueous zinc-ion batteries.

[0004] To achieve the above technical purposes, the application adopts the following technical solutions:

[0005] An electrolyte additive for constructing an organic anion-rich interface to inhibit zinc dendrites is composed of acetylsulfanilic acid ions (C4H4NO4S - ) and potassium ions (K + ), and has the following structural formula:

[0006]

[0007] An aqueous zinc-ion battery electrolyte containing the above-mentioned additive is composed of the additive, a soluble zinc salt and deionized water, the additive constructs an organic anion-rich interface on the surface of zinc; the soluble zinc salt is zinc sulfate with a chemical formula of ZnSO4·7H2O and a molar concentration of 1-3 mol; and the additive is potassium acetylsulfanilate with a chemical formula of C4H4KNO4S and a molar concentration of 1-100 mmol / L in the aqueous zinc-ion battery electrolyte.

[0008] As a preferred, the molar concentration of the soluble zinc salt is 2 mol / L; and the molar concentration of the additive in the aqueous zinc-ion battery electrolyte is 10 mmol / L.

[0009] The solvent of the electrolyte is deionized water; and the pH value of the electrolyte is 3-6.

[0010] The aqueous zinc ion battery prepared by using the electrolyte is a Zn||Zn symmetric battery assembled by using zinc metal as a negative electrode, zinc metal as a positive electrode, glass fiber as a diaphragm and the aqueous zinc ion battery electrolyte.

[0011] The electrolyte additive of the application can be used in a zinc ion electrochemical energy storage device.

[0012] Beneficial effects:

[0013] 1. Potassium acetylsulfamine has high solubility in water, and has significant stability in heat and acidity, so that it becomes an electrolyte additive suitable for low-cost, non-toxic and safe application.

[0014] 2. The application introduces potassium acetylsulfamine additive in the electrolyte, and the acetylsulfamine ion therein can be adsorbed on the surface of the zinc negative electrode to construct an organic anion enrichment interface, so as to form a poor water double layer on the zinc surface and inhibit the occurrence of hydrogen evolution and zinc corrosion.

[0015] 3. The application introduces potassium acetylsulfamine additive in the electrolyte, and the acetylsulfamine ion at the interface can form a coordination bond with zinc ion through different donor atoms, increase the nucleation overpotential of zinc deposition, refine the grain, and better inhibit the growth of zinc dendrites.

[0016] 4. The application introduces potassium acetylsulfamine additive in the electrolyte, and the acetylsulfamine ion therein can be decomposed into a solid electrolyte interface film rich in zinc sulfide in the process of electrochemical cycle, further inhibiting dendrite growth and side reactions.

[0017] 5. The application introduces a small amount of potassium acetylsulfamine additive in the zinc sulfate electrolyte, and the electrolyte is assembled into a Zn||Zn symmetric battery with a zinc metal positive electrode, a zinc metal negative electrode and a glass fiber diaphragm. 2 And 1 mAh / cm 2 Under the condition of 2 mA / cm

[0018] 6. The application also provides an application example of the above-mentioned potassium acetylsulfamine additive in a zinc-manganese battery. The negative electrode of the zinc-manganese battery is metal zinc, and the positive electrode is manganese dioxide. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 is a schematic diagram of the action mechanism of the aqueous zinc ion battery electrolyte provided by the application;

[0020] Figure 2are the cycle life test figures of zinc symmetric battery in ZnSO4 electrolyte and ZnSO4 electrolyte containing potassium acetylsulfanilate;

[0021] Figure 3 are the optical microscope figures of in-situ observation of zinc deposition by optical microscope; wherein, figure a is the optical microscope figure of zinc electrodeposition in ZnSO4 electrolyte, figure b is the optical microscope figure of zinc electrodeposition in ZnSO4 electrolyte containing potassium acetylsulfanilate;

[0022] Figure 4 are the atomic force microscope 2D and 3D topography figures of zinc foil after cycling in ZnSO4 electrolyte and ZnSO4 electrolyte containing potassium acetylsulfanilate; wherein, figure a is the atomic force microscope 2D and 3D topography figure of zinc after cycling in ZnSO4 electrolyte, figure b is the atomic force microscope 2D and 3D topography figure of zinc after cycling in ZnSO4 electrolyte containing potassium acetylsulfanilate;

[0023] Figure 5 are the nucleation overpotential figures measured in ZnSO4 electrolyte and ZnSO4 electrolyte containing potassium acetylsulfanilate;

[0024] Figure 6 are the linear voltammetry scan test figures measured in ZnSO4 electrolyte and ZnSO4 electrolyte containing potassium acetylsulfanilate;

[0025] Figure 7 are the scanning electron microscope figures of zinc foil after immersion in ZnSO4 electrolyte and ZnSO4 electrolyte containing potassium acetylsulfanilate for 2 weeks; wherein, figure a is the scanning electron microscope figure of zinc after immersion in ZnSO4 electrolyte, figure b is the scanning electron microscope figure of zinc after immersion in ZnSO4 electrolyte containing potassium acetylsulfanilate;

[0026] Figure 8 are the XRD figures of zinc foil after cycling for 10 and 30 cycles in ZnSO4 electrolyte and ZnSO4 electrolyte containing potassium acetylsulfanilate;

[0027] Figure 9 are the cycle performance test figures of zinc-manganese battery in ZnSO4 electrolyte and ZnSO4 electrolyte containing potassium acetylsulfanilate. DETAILED DESCRIPTION

[0028] The application will be further described below in combination with examples and drawings.

[0029] The application adopts an electrolyte with an organic anion-rich interface configured to inhibit zinc dendrite in zinc ion battery, so as to realize long cycle life of aqueous zinc ion battery. The electrolyte additive used in the aqueous zinc ion battery is potassium acetylsulfanilate, which is composed of acetylsulfanilate ion (C4H4NO4S - ) and potassium ion (K +) composition, in short ACE.

[0030] Example 1:

[0031] First, an aqueous zinc-ion battery electrolyte without additives was prepared. 1 mol of zinc sulfate was dissolved in deionized water, and the volume was made up to 500 ml in a volumetric flask to obtain a 2 mol / L ZnSO4 electrolyte, which was the aqueous zinc-ion battery electrolyte for the comparative test.

[0032] The aqueous zinc-ion battery electrolyte of this example was composed of a soluble zinc salt electrolyte and an electrolyte additive. 1-100 mmol of potassium acetylsulfanilate additive was added to the above prepared 2 mol / L ZnSO4 electrolyte, and the potassium acetylsulfanilate was dissolved by stirring, to finally obtain an aqueous zinc-ion battery electrolyte containing an additive. The above prepared electrolyte was matched with a zinc metal positive electrode, a zinc metal negative electrode, and a glass fiber separator, and a Zn||Zn symmetric battery was assembled by sealing and assembling the coin cell with a tablet press.

[0033] Figure 1 is the mechanism of action of the electrolyte additive. Acetylsulfanilate ions can be adsorbed on the surface of the zinc negative electrode, and an organic anion-rich interface is constructed on the surface of the zinc negative electrode, while a water-poor double layer is formed, which can inhibit the occurrence of hydrogen evolution and zinc corrosion. Moreover, the acetylsulfanilate ions at the interface can form coordination bonds with zinc ions through different donor atoms, increase the nucleation overpotential of zinc deposition, refine the grain size, and better inhibit the growth of zinc dendrites. In addition, acetylsulfanilate ions can be decomposed into a solid electrolyte interface film rich in zinc sulfide during electrochemical cycling, which can further inhibit dendrite growth and side reactions.

[0034] Example 2:

[0035] This example is basically the same as Example 1, except that the amount of potassium acetylsulfanilate added is optimized. The optimal concentration of potassium acetylsulfanilate in the electrolyte is 10 mmol / L.

[0036] In the Zn||Zn symmetric battery, the respective cycle times are as shown in Figure 2 The Zn||Zn symmetric battery without ACE addition short-circuits in less than 150 hours of cycling; while the Zn||Zn symmetric battery with 10 mmol ACE addition has a cycle time of more than 4600 hours (up to 6 months), and the cycle life of the battery is significantly prolonged.

[0037] The deposition phenomena of zinc in the electrolyte with and without ACE were observed in situ by optical microscopy. As shown in Figure 3 a, in the electrolyte without ACE, many protruding zinc dendrites were formed on the zinc surface after 30 minutes; while as shown in Figure 3As shown in b, in the electrolyte using ACE, the zinc surface exhibits a uniform morphology throughout the electroplating process.

[0038] Electrochemical cycling was performed on a Zn||Zn symmetric cell, and the 2D and 3D morphology of the zinc foil was observed using atomic force microscopy. For example... Figure 4 As shown in Figure a, in the electrolyte without ACE, the zinc surface with deposited zinc exhibits a rough and wavy morphology, indicating high roughness; while... Figure 4 As shown in b, in an electrolyte using ACE, the zinc foil with deposited zinc has a smoother surface and less roughness.

[0039] Nucleation overpotential tests were performed on Zn||Zn symmetric cells in two different electrolytes, such as... Figure 5 As shown in the figure, compared with electrolytes without ACE, electrolytes containing ACE exhibit a higher nucleation overpotential, which can induce the growth of smaller and denser zinc nuclei and better suppress zinc dendrite growth.

[0040] The strength of the hydrogen evolution side reaction on the zinc anode surface was determined by testing the electrolyte using a linear voltammetric method. Figure 6 As shown, compared with the electrolyte without ACE, the hydrogen evolution potential on the zinc anode surface in the electrolyte containing ACE shifts negatively, indicating that the degree of hydrogen evolution side reaction is reduced.

[0041] The surface morphology of zinc foil immersed in electrolytes without and with ACE for two weeks was observed using scanning electron microscopy. Figure 7 As shown in Figure a, zinc foil immersed in an electrolyte without ACE has accumulated corrosion byproducts on its surface; while... Figure 7 As shown in b, the zinc foil surface immersed in an electrolyte containing ACE remained smooth, with no corrosion byproducts or visible morphological changes.

[0042] The Zn||Zn symmetric cells were electrochemically cycled 10 and 30 times in two different electrolytes. The cells were then disassembled, and the XRD patterns of the zinc foil were compared using an X-ray diffractometer. Figure 8 As shown. In the electrolyte without added ACE, the relative intensities (R = I) of the (002) peak and the (101) peak of the zinc foil are... 002 / I 101 The intensity of the (002) peak gradually decreased with increasing cycle number; however, in the electrolyte with ACE, the relative intensity of the (002) peak and (101) peak of the zinc foil gradually increased with increasing cycle number, indicating that the additive promoted the preferential alignment of the Zn (002) plane. Furthermore, the introduction of the ACE additive reduced undesirable byproducts ((Zn(OH)2)3(ZnSO4)(H2O). X The generation of ).

[0043] Example 3:

[0044] This example is basically the same as Example 2, except that the positive material is replaced by manganese dioxide instead of zinc. The zinc metal is used as the negative electrode, the manganese dioxide is used as the positive electrode, the glass fiber is used as the separator, and the 2 mol / L ZnSO4 solution containing 10 mmol / L potassium acetylsulfanate is used as the electrolyte to assemble the Zn||MnO2 battery.

[0045] The ACE is applied to the Zn||MnO2 battery for cycle performance test, as shown in Figure 9 In the electrolyte with ACE, the discharge capacity of the Zn||MnO2 battery is always higher than that of the electrolyte without ACE. After 500 cycles, the Zn||MnO2 battery in the electrolyte with ACE still has an excellent coulombic efficiency of 99.79%.

[0046] In summary, the above embodiments and test data show that the method of the present application is simple, low-cost and effective, and has important significance for inhibiting dendrite growth and side reactions in aqueous zinc ion batteries and promoting the long-life application of aqueous zinc ion batteries in the future.

[0047] It should be noted that the above description is only a specific embodiment of the present application and is not used to limit the protection scope of the present application. Any non-essential improvements and adjustments made to the present application within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. An electrolyte configured to inhibit zinc dendrites with an organic anion-enriched interface, characterized in that: The additive forms an organic anion-rich interface on the zinc surface; the soluble zinc salt is zinc sulfate with a chemical formula of ZnSO4.7H2O and a molar concentration of 1-3 mol; and the additive is potassium acetylsulfanilate with a chemical formula of C4H4KNO4S and a molar concentration of 1-100 mmol / L in the aqueous zinc ion battery electrolyte.

2. The electrolyte configured to suppress zinc dendrite growth with an organic anion-enriched interface of claim 1, wherein: The molar concentration of the soluble zinc salt is 2 mol / L; and the molar concentration of the additive in the aqueous zinc ion battery electrolyte is 10 mmol / L.

3. The electrolyte configured to inhibit zinc dendrite growth with an organic anion-enriched interface of claim 1, wherein: The solvent of the electrolyte is deionized water; and the pH value of the electrolyte is 3-6.

4. A water-based zinc ion battery prepared by using the electrolyte solution according to claim 1 or 2 or 3, characterized in that: The zinc metal is used as the negative electrode and the positive electrode, glass fiber is used as the separator, and the aqueous zinc ion battery electrolyte is used to assemble a Zn||Zn symmetric battery.

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