An aqueous zinc-ion battery electrolyte, an aqueous zinc-ion battery and a preparation method thereof

Abstract

The present invention belongs to the technical field of battery electrolytes, and specifically relates to an aqueous zinc ion battery electrolyte, an aqueous zinc ion battery, and a preparation method. The aqueous zinc ion battery electrolyte provided by the present invention comprises components of a solvent, a zinc salt, sucralose, and hydroxypropyl distarch phosphate. Sucralose can be adsorbed onto the anode / electrolyte interface through chemical interactions, effectively alleviating the problems of interfacial byproducts and dendrite growth, and can also reduce the nucleation overpotential of zinc, increase nucleation sites, promote uniform nucleation, and perform 3D diffusion growth, thereby reducing the polarization voltage of the battery during charge and discharge, and obtaining a uniform zinc deposition surface dominated by the (002) crystal plane. Hydroxypropyl distarch phosphate can react with water to inhibit the reactivity of water, thereby inhibiting the occurrence of water-related side reactions during charge and discharge. Aqueous zinc ion batteries based on this electrolyte have high discharge specific capacity and cycle stability.

Description

Technical Field

[0001] The present invention belongs to the technical field of batteries, and particularly relates to an aqueous zinc ion battery electrolyte capable of inhibiting dendrites and by-products, a preparation method thereof, and an aqueous zinc ion battery prepared from the aqueous zinc ion battery electrolyte. Background Art

[0002] The rapid development of electric vehicles, particularly the growing demand for high-energy-consuming end devices, has significantly driven the research and advancement of rechargeable metal-ion battery technology. Against this backdrop, the development of grid-scale energy storage systems (ESS) has become an inevitable trend to ensure the stability of power supply to end devices. Within ESS, lithium-ion batteries maintain their prominent position due to their superior energy density and voltage platform. However, due to the high cost of lithium resources and the safety risks of organic electrolytes, lithium-ion batteries face significant challenges in large-scale energy storage applications. Therefore, the search for suitable alternative metals, such as sodium (Na), potassium (K), magnesium (Mg), aluminum (Al), and zinc (Zn), has become a research hotspot in the energy storage field, and these metal elements have been widely used in energy storage technologies.

[0003] Among these candidate metals, rechargeable aqueous zinc-ion batteries (AZIBs) are considered highly suitable for ESS applications due to their high safety, low cost, high theoretical capacity (820 mAh / g, 5855 mAh / cm³), favorable redox potential (0.76 V vs. standard hydrogen electrode (SHE), and high abundance in the Earth's crust. Despite this, the Zn anode in AZIBs faces a number of challenges, including the hydrogen evolution reaction (HER), corrosion side reactions, and Zn dendrite growth. Zn metal is thermodynamically unstable in aqueous environments and readily generates hydrogen gas and passivation byproducts at the Zn-electrolyte interface. This not only consumes excess electrolyte, reducing the Coulombic efficiency (CE) of the battery, but also affects cycling stability and may even lead to battery failure. Furthermore, the "tip effect" causes Zn ions to continuously deposit at locations of high current density and curvature, forming Zn dendrites. This uncontrolled dendrite growth can pierce the separator and trigger battery short circuits. Therefore, mitigating side reactions at the Zn anode interface and controlling Zn dendrite growth are crucial for promoting the large-scale application of AZIBs.

[0004] Regarding the inhibition of dendrite growth, the role of additives can be summarized as electrostatic shielding and crystal surface modulation effects. The charged cationic additives in the electrolyte accumulate at the tip position with a higher charge density, promoting the three-dimensional diffusion process of zinc ions and inhibiting the growth of zinc dendrites. The growth of dendrites is mainly attributed to the large-angle (>70°) Zn (100) and Zn (101) plane deposition sheets. The Zn (002) plane is deposited at an angle of less than 30°, has very high stability and corrosion resistance, and can effectively inhibit the growth of dendrites. Therefore, it is necessary to select suitable additives to reduce the surface energy and induce the diffusion and deposition of zinc ions to the Zn (002) plane. Summary of the Invention

[0005] One of the objectives of the present invention is to provide an aqueous zinc ion battery electrolyte, which significantly inhibits dendrites and byproducts and improves battery performance by adding sucralose and hydroxypropyl distarch phosphate to the electrolyte to adjust the electrode / electrolyte interface.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: an aqueous zinc ion battery electrolyte, comprising components including a solvent, a zinc salt and an additive, wherein the additive is sucralose and hydroxypropyl distarch phosphate, the additive is added to the solvent at a concentration of 2-35wt%, and the zinc salt is added to the solvent at a concentration of 0.5-5mol / kg.

[0007] As a further improvement of aqueous zinc ion battery electrolyte:

[0008] Preferably, the mass ratio of sucralose to hydroxypropyl distarch phosphate is 1:10-10:1.

[0009] Preferably, the solvent is deionized water.

[0010] Preferably, the zinc salt is ZnSO4 or Zn(ClO4)2.

[0011] A second object of the present invention is to provide a method for preparing the above-mentioned aqueous zinc ion battery electrolyte: comprising the following steps: adding sucralose and hydroxypropyl distarch phosphate to a solvent and dissolving them to obtain a mixed solution of sucralose and hydroxypropyl distarch phosphate, then adding zinc salt, and stirring uniformly to obtain an aqueous zinc ion battery electrolyte.

[0012] A third object of the present invention is to provide an aqueous zinc ion battery prepared using the above aqueous zinc ion battery electrolyte.

[0013] As a further improvement of aqueous zinc-ion batteries:

[0014] Preferably, the aqueous zinc ion battery is assembled by stacking a positive electrode, a diaphragm, a negative electrode, a gasket and a spring in sequence and then injecting an aqueous zinc ion battery electrolyte.

[0015] Preferably, the positive electrode is NH4V4O 10 Or copper sheet.

[0016] Preferably, the diaphragm is glass fiber or filter paper.

[0017] Preferably, the negative electrode is a zinc sheet.

[0018] The beneficial effects of the present invention compared to the prior art are:

[0019] (1) The present invention provides an aqueous zinc ion battery electrolyte, which innovatively introduces sucralose and hydroxypropyl distarch phosphate as co-additives into a zinc salt electrolyte to obtain an electrolyte solution with good electrical conductivity, thereby regulating the zinc deposition kinetics during the charge and discharge process of the aqueous zinc ion battery and inhibiting the activity of water, thereby improving the reversibility of the zinc negative electrode. Sucralose can be adsorbed onto the anode / electrolyte interface through chemical interactions, which can effectively alleviate the problems of interfacial byproducts and dendrite growth. It can also reduce the nucleation overpotential of zinc, increase the nucleation sites, promote uniform nucleation, and perform 3D diffusion growth, thereby reducing the polarization voltage of the battery during the charge and discharge process and obtaining a uniform zinc deposition surface dominated by the (002) crystal plane. Hydroxypropyl distarch phosphate can react with water, inhibit the reaction activity of water, and thus inhibit the occurrence of water-related side reactions during the charge and discharge process. The aqueous zinc ion battery based on this electrolyte has a high discharge specific capacity and cycle stability.

[0020] (2) The present invention successfully prepared a new electrolyte by adding a small amount of low-cost additives to a low-concentration salt solution and applied it to zinc ion energy storage batteries. This innovative method significantly improves battery performance by promoting the diffusion and deposition of zinc ions on the Zn (002) plane while effectively inhibiting the by-products produced by water decomposition. The synthesis process is simple and does not require complex pretreatment steps. The developed battery can be charged and discharged at high current density and exhibits excellent cycle stability under high specific capacity conditions. By assembling an aqueous zinc ion battery electrolyte with a positive electrode, a zinc sheet, a gasket and a shrapnel, we successfully constructed an aqueous zinc ion battery. Compared with the prior art, the zinc ion battery of the present invention performs well in terms of cycle stability and reversibility, with a lower zinc ion nucleation barrier, a higher discharge specific capacity and a slower positive electrode capacity decay. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 10mA / cm 2 XRD comparison diagrams of zinc sheets deposited in different electrolytes prepared in Example 1 and Comparative Examples 1, 2, and 3 for 1 hour at different current densities.

[0022] Figure 2The electrolytes of Example 1 and Comparative Examples 1, 2 and 3 were used to assemble Zn / / Zn symmetrical cells. -2 Up to 20 mAh cm -2 Comparison chart of cycle performance under test conditions.

[0023] Figure 3 To assemble Zn / / Cu batteries using the electrolytes of Example 1 and Comparative Examples 1, 2, and 3, at 0.5 mA cm -2 Up to 0.5 mAh cm -2 Coulombic efficiency under test conditions.

[0024] Figure 4 To assemble Zn / / NH4V4O using the electrolytes of Example 1 and Comparative Examples 1, 2 and 3 10 Full battery, at 5Ag -1 Comparison of cycling performance under different current densities. DETAILED DESCRIPTION

[0025] In order to make the objectives, technical solutions and advantages of the present invention more clear, the present invention is further described in detail below in conjunction with the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0026] Example 1

[0027] This embodiment provides an aqueous zinc ion battery electrolyte capable of suppressing dendrites and byproducts, and a preparation method thereof comprises the following steps:

[0028] S1. Add 1 g of sucralose and 1 g of hydroxypropyl distarch phosphate to 100 g of deionized water and dissolve them by ultrasonication to obtain a mixed solution; the total concentration of the two additives in the deionized water is 2 wt %;

[0029] S2. Add 0.1 mol of zinc perchlorate (the added concentration in deionized water is 1 mol / kg) to the mixed solution and stir evenly to prepare an aqueous zinc ion battery electrolyte 1 capable of suppressing dendrites and by-products.

[0030] Example 2

[0031] This embodiment provides an aqueous zinc ion battery electrolyte capable of suppressing dendrites and byproducts, and a preparation method thereof comprises the following steps:

[0032] S1. Add 17.5 g of sucralose and 17.5 g of hydroxypropyl distarch phosphate to 100 g of deionized water and dissolve them by ultrasonication to obtain a mixed solution; the total concentration of the two additives in the deionized water is 35 wt %;

[0033] S2. Add 0.05 mol of ZnSO4 (the added concentration in deionized water is 0.5 mol / kg) to the mixed solution and stir evenly to prepare an aqueous zinc ion battery electrolyte 2 capable of suppressing dendrites and by-products.

[0034] Example 3

[0035] This embodiment provides an aqueous zinc ion battery electrolyte capable of suppressing dendrites and byproducts, and a preparation method thereof comprises the following steps:

[0036] S1. Add 10 g of sucralose and 1 g of hydroxypropyl distarch phosphate to 100 g of deionized water and dissolve them by ultrasonication to obtain a mixed solution; the total concentration of the two additives in the deionized water is 11 wt %;

[0037] S2. Add 0.3 mol of zinc perchlorate (the added concentration in deionized water is 3 mol / kg) to the mixed solution and stir evenly to prepare aqueous zinc ion battery electrolyte 3 capable of suppressing dendrites and by-products.

[0038] Example 4

[0039] This embodiment provides an aqueous zinc ion battery electrolyte capable of suppressing dendrites and byproducts, and a preparation method thereof comprises the following steps:

[0040] S1. Add 1 g of sucralose and 10 g of hydroxypropyl distarch phosphate to 100 g of deionized water and dissolve them by ultrasonication to obtain a mixed solution; the total concentration of the two additives in the deionized water is 11 wt %;

[0041] S2. Add 0.5 mol of zinc perchlorate (the concentration in deionized water is 5 mol / kg) to the mixed solution and stir evenly to prepare aqueous zinc ion battery electrolyte 4 capable of suppressing dendrites and by-products.

[0042] Comparative Example 1

[0043] This comparative example provides an aqueous zinc ion battery electrolyte, the preparation method of which comprises the following steps:

[0044] S1. Add 5 g of sucralose to 100 g of deionized water and dissolve it by ultrasonication to a concentration of 5 wt % to prepare a sucralose solution;

[0045] S2. Add 0.1 mol of zinc perchlorate (the added concentration in deionized water is 1 mol / kg) to the sucralose solution to prepare a common aqueous zinc ion battery electrolyte 1.

[0046] Comparative Example 2

[0047] This embodiment provides an aqueous zinc ion battery electrolyte, and the preparation method thereof comprises the following steps:

[0048] S1. Add 5 g of hydroxypropyl distarch phosphate to 100 g of deionized water and dissolve it by ultrasonication to a concentration of 5 wt % to obtain a hydroxypropyl distarch phosphate solution;

[0049] S2. Add 0.1 mol of zinc perchlorate (the added concentration in deionized water is 1 mol / kg) to the hydroxypropyl distarch phosphate solution to prepare a common aqueous zinc ion battery electrolyte 2.

[0050] Comparative Example 3

[0051] This embodiment provides a pure zinc perchlorate electrolyte, the preparation method of which includes the following steps:

[0052] 0.2 mol of zinc perchlorate was added to 100 g of deionized water at a concentration of 2 mol / kg, and ultrasonically dissolved to prepare an additive-free ordinary aqueous zinc ion battery electrolyte 3.

[0053] Performance test comparison:

[0054] Figure 1 The zinc sheet was deposited in different electrolytes prepared in Example 1 and Comparative Examples 1, 2, and 3. Both the positive and negative electrodes were zinc sheets. The specific test steps were as follows: 10 mA / cm 2 At the current density, XRD test was performed on the positive zinc sheet after discharge for 1 hour; Figure 1 It can be seen that compared with the pure zinc perchlorate electrolyte (2 mol / kg, without additives) of Comparative Example 3 and the electrolyte with only hydroxypropyl distarch phosphate added in Comparative Example 2, the electrolyte containing sucralose in Example 1 showed obvious (002) crystal plane orientation growth, indicating that the addition of sucralose can induce the growth of (002) crystal plane texture and inhibit the growth of zinc dendrites.

[0055] Figure 2 The cycling stability of Zn / / Zn pair batteries was compared. The different electrolytes prepared in Example 1 and Comparative Examples 1, 2, and 3 were assembled with the positive electrode (zinc sheet), separator (glass fiber), negative electrode (zinc sheet), gasket, and spring to form a Zn / Zn pair battery. The specific test steps are as follows: Apply 20 mA cm -2 The current is fed to the symmetrical battery and the curve of polarization voltage versus time is recorded. -2 -20mAh cm -2Under the test conditions, the cyclic stability performance of the mixed additive system of sucralose and hydroxypropyl distarch phosphate was significantly improved compared with the pure zinc perchlorate electrolyte of Comparative Example 3 and the electrolytes of Comparative Examples 1 and 2 with only sucralose or hydroxypropyl distarch phosphate added.

[0056] Figure 3 The coulombic efficiency of Zn / / Cu half-cells prepared with different electrolytes from Example 1, Comparative Examples 1, 2, and 3 was compared. A Zn / / Cu half-cell was assembled with the aqueous zinc ion battery electrolyte, a positive electrode (Cu sheet), a separator (filter paper), a negative electrode (zinc sheet), a gasket, and a spring. A 0.5 mA cm -2 The charge and discharge current is 1000V, the discharge time is 60 minutes, the charge cut-off voltage is 0.5V, and the change trend of Coulomb efficiency with the number of cycles is recorded. Figure 3 It can be seen that the average coulombic efficiency of the Zn / / Cu half-cell containing sucralose and hydroxypropyl distarch phosphate additives is 99.4%, which is significantly higher than the pure zinc perchlorate electrolyte of Comparative Example 3 and the electrolytes of Comparative Examples 1 and 2 with only sucralose or hydroxypropyl distarch phosphate added.

[0057] Figure 4 The cycling stability of full batteries assembled with different electrolytes prepared in Example 1, Comparative Example 1, Comparative Example 2, and Comparative Example 3 were compared. 10 , the negative electrode is zinc sheet, the specific test steps are as follows: the current density is 5A -1 When the specific capacity of the Zn / / NVO full battery changes with the number of cycles, the trend is recorded. Figure 4 As shown in Figure 2, the initial specific capacity of the electrolyte containing sucralose and hydroxypropyl distarch phosphate additives was as high as 301.72 mAh g -1 , and it still has a retention rate of 93% after 1000 cycles, indicating that the positive electrode specific capacity decays slowly and the cycle stability is significantly higher than that of the pure zinc perchlorate electrolyte in Comparative Example 3 and the electrolytes in Comparative Examples 1 and 2 with only sucralose or hydroxypropyl distarch phosphate added.

[0058] The different electrolytes prepared in Examples 2, 3, and 4 were assembled with the positive electrode (zinc sheet), separator (glass fiber), negative electrode (zinc sheet), gasket, and spring to form Zn / / Zn pair batteries. -2 -20mAh cm -2 Under the test conditions, the Zn / / Zn pair battery can stably cycle for 60 hours, 86 hours and 75 hours, respectively, which are better than the pure zinc perchlorate electrolyte and the electrolyte with only sucralose or hydroxypropyl distarch phosphate added, confirming the effectiveness of the additives in the electrolytes of Examples 2, 3 and 4.

[0059] Those skilled in the art will appreciate that the foregoing descriptions are merely specific embodiments of the present invention, and not exhaustive. It should be noted that numerous variations and modifications are possible for those skilled in the art, and all such variations and modifications that do not exceed the scope of the claims should be considered within the scope of protection of the present invention.

Claims

1. An aqueous zinc ion battery electrolyte, characterized in that The components include a solvent, a zinc salt and an additive. The additive is sucralose and hydroxypropyl distarch phosphate. The concentration of the additive in the solvent is 2-35wt%, and the concentration of the zinc salt in the solvent is 0.5-5mol / kg.

2. The aqueous zinc ion battery electrolyte according to claim 1, wherein The mass ratio of the sucralose to hydroxypropyl distarch phosphate is 1:10-10:

1.

3. The aqueous zinc ion battery electrolyte according to claim 1, wherein The solvent is deionized water.

4. The aqueous zinc ion battery electrolyte according to claim 1, wherein The zinc salt is ZnSO4 or Zn(ClO4)2.

5. A method for preparing the aqueous zinc ion battery electrolyte according to any one of claims 1 to 4, characterized in that: The method comprises the following steps: adding sucralose and hydroxypropyl distarch phosphate into a solvent and dissolving them to obtain a mixed solution of sucralose and hydroxypropyl distarch phosphate; then adding zinc salt and stirring the mixture to obtain an aqueous zinc ion battery electrolyte.

6. An aqueous zinc ion battery prepared from the aqueous zinc ion battery electrolyte according to any one of claims 1 to 4.

7. The aqueous zinc ion battery according to claim 6, wherein The aqueous zinc ion battery is assembled by stacking a positive electrode, a diaphragm, a negative electrode, a gasket and a spring in sequence and then injecting an aqueous zinc ion battery electrolyte.

8. The aqueous zinc ion battery according to claim 7, wherein The positive electrode is NH4V4O 10 Or copper sheet.

9. The aqueous zinc ion battery according to claim 7, wherein The diaphragm is glass fiber or filter paper.

10. The aqueous zinc ion battery according to claim 7, characterized in that The negative electrode is a zinc sheet.

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