Aqueous zinc ion battery electrolyte, aqueous zinc ion battery and preparation method

Abstract

The invention belongs to the technical field of battery electrolyte, and particularly relates to aqueous zinc ion battery electrolyte, an aqueous zinc ion battery and a preparation method. The aqueous zinc ion battery electrolyte provided by the invention comprises the following components: a solvent, zinc salt, sucralose and hydroxy propyl distarch phosphate. Wherein the sucralose can be adsorbed to an anode / electrolyte interface through chemical interaction, the growth problem of interface byproducts and dendrites can be effectively relieved, the nucleation overpotential of zinc can be reduced, nucleation sites are increased, uniform nucleation is promoted, and 3D diffusion growth is carried out, so that the polarization voltage of the battery in the charging and discharging process is reduced, and the service life of the battery is prolonged. And a uniform zinc deposition surface mainly comprising a (002) crystal face is obtained. The hydroxy propyl distarch phosphate can act with water to inhibit the reaction activity of the water, so that side reactions related to the water in the charging and discharging process are inhibited. The aqueous zinc ion battery based on the electrolyte has relatively high specific discharge capacity and cycling 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 suppressing 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 in the field of electric vehicles, especially the growing demand for high-energy-consuming terminal devices, has greatly promoted the research and progress of rechargeable metal ion battery technology. Against this background, in order to ensure the stability of power supply for terminal devices, the development of grid-scale energy storage systems (ESS) has become an inevitable trend. In the field of ESS, lithium-ion batteries maintain their important position due to their excellent 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 major challenges in large-scale energy storage applications. Therefore, finding 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 very suitable for ESS applications due to their high safety, low cost, high theoretical capacity (820 mAh / g, 5855 mAh / cm³), suitable redox potential (0.76 V relative to the standard hydrogen electrode SHE), and high abundance in the earth's crust. Nevertheless, the zinc anode in AZIBs still faces a series of challenges, including hydrogen evolution reaction (HER), corrosion side reactions, and the growth of zinc dendrites. Zinc metal is thermodynamically unstable in an aqueous environment and easily generates hydrogen and passivation by-products at the zinc electrolyte interface, which not only consumes too much electrolyte, reduces the coulombic efficiency (CE) of the battery, but also affects the cycle stability of the battery and may even lead to battery failure. In addition, the "tip effect" causes zinc ions to continuously deposit at positions with high current density and curvature, forming zinc dendrites. This uncontrolled dendrite growth will pierce the separator and cause battery short circuit. Therefore, reducing side reactions at the zinc anode interface and controlling the growth of zinc dendrites 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 positions 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 deposition flakes on the large-angle (>70°) Zn(100) and Zn(101) planes. The Zn(002) plane deposits at an angle of less than 30°, with very high stability and corrosion resistance, which can effectively inhibit the growth of dendrites. Therefore, it is necessary to select appropriate additives to reduce the surface energy and induce the diffusion and deposition of zinc ions onto 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 can regulate the electrode / electrolyte interface by adding sucralose and hydroxypropyl distarch phosphate to the electrolyte, thereby significantly inhibiting dendrites and by-products and improving the battery performance.

[0006] To achieve the above objective, the present invention adopts the following technical solution: An aqueous zinc-ion battery electrolyte, the components of which include a solvent, a zinc salt, and an additive. The additive is sucralose and hydroxypropyl distarch phosphate. The addition concentration of the additive in the solvent is 2-35 wt%, and the addition concentration of the zinc salt in the solvent is 0.5-5 mol / kg.

[0007] As a further improvement of the aqueous zinc-ion battery electrolyte: Preferably, the mass ratio of sucralose to hydroxypropyl distarch phosphate is 1:10-10:1.

[0008] Preferably, the solvent is deionized water.

[0009] Preferably, the zinc salt is ZnSO4 or Zn(ClO4)2.

[0010] Another objective of the present invention is to provide a preparation method for the above aqueous zinc-ion battery electrolyte, which includes the following steps: adding sucralose and hydroxypropyl distarch phosphate to the solvent and dissolving them to obtain a mixed solution of sucralose and hydroxypropyl distarch phosphate, and then adding the zinc salt and stirring evenly to obtain the aqueous zinc-ion battery electrolyte.

[0011] Another objective of the present invention is to provide an aqueous zinc-ion battery prepared with the above aqueous zinc-ion battery electrolyte.

[0012] As a further improvement of the aqueous zinc-ion battery: Preferably, the aqueous zinc-ion battery is assembled by stacking a positive electrode, a separator, a negative electrode, a gasket, and a spring piece in sequence and then injecting the aqueous zinc-ion battery electrolyte.

[0013] Preferably, the positive electrode is NH4V4O 10 or a Cu sheet.

[0014] Preferably, the separator is glass fiber or filter paper.

[0015] Preferably, the negative electrode is a zinc sheet.

[0016] The beneficial effects of the present invention compared with the prior art are as follows: (1) The present invention provides an aqueous zinc-ion battery electrolyte. Innovatively, sucralose and hydroxypropyl distarch phosphate are introduced as co-additives into the zinc salt electrolyte to obtain an electrolyte solution with good conductivity, so as to regulate the zinc deposition kinetics during the charge and discharge process of the aqueous zinc-ion battery and inhibit the activity of water, thereby improving the reversibility of the zinc negative electrode. Among them, sucralose can be adsorbed onto the anode / electrolyte interface through chemical interactions, which can effectively alleviate the problems of interface by-products and dendrite growth, and can also reduce the nucleation overpotential of zinc, increase the nucleation sites, promote uniform nucleation, and carry out 3D diffusion growth, so that the polarization voltage during the charge and discharge process of the battery is reduced, and a uniform zinc deposition surface mainly composed of the (002) crystal plane is obtained. And hydroxypropyl distarch phosphate can interact with water to inhibit the reaction activity of water, thereby inhibiting the occurrence of side reactions related to water during the charge and discharge process. The aqueous zinc-ion battery based on this electrolyte has a high discharge specific capacity and cycle stability performance.

[0017] (2) The present invention successfully prepares a novel electrolyte by adding a small amount of low-cost additives to a low-concentration salt solution and applies it to a zinc-ion energy storage battery. This innovative method promotes the diffusion and deposition of zinc ions on the Zn(002) plane, and at the same time effectively inhibits the by-products generated by water decomposition, significantly improving the battery performance. The synthesis process is simple and does not require complex pretreatment steps. The developed battery can be charged and discharged at a high current density and exhibits excellent cycle stability under high specific capacity conditions. By assembling the aqueous zinc-ion battery electrolyte with a positive electrode, a zinc sheet, a gasket, and a spring sheet, we successfully constructed an aqueous zinc-ion battery. Compared with the prior art, the zinc-ion battery of the present invention shows excellent performance in terms of cycle stability and reversibility, has a lower zinc ion nucleation barrier, a higher discharge specific capacity, and a slower positive electrode capacity decay. Description of the Drawings

[0018] Figure 1 At a current density of 10 mA / cm 2 XRD comparison diagrams of the zinc sheet deposited for 1 hour in different electrolytes prepared in Example 1 and Comparative Example 1, Comparative Example 2, and Comparative Example 3, respectively.

[0019] Figure 2To assemble Zn / / Zn symmetric cells using the electrolytes of Example 1 and Comparative Examples 1, 2, and 3, the cycling performance comparison chart under the test conditions of 20 mA cm -2 to 20 mAh cm -2 is shown in the figure.

[0020] Figure 3 To assemble Zn / / Cu cells using the electrolytes of Example 1 and Comparative Examples 1, 2, and 3, the Coulombic efficiency under the test conditions of 0.5 mA cm -2 to 0.5 mAh cm -2 is shown in the figure.

[0021] Figure 4 To assemble Zn / / NH4V4O 10 full cells using the electrolytes of Example 1 and Comparative Examples 1, 2, and 3, the cycling performance comparison chart under the current density of 5 A g -1 is shown in the figure. Detailed implementation manners

[0022] In order to make the objectives, technical solutions, and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below in conjunction with embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

[0023] Example 1 This example provides an aqueous zinc-ion battery electrolyte capable of inhibiting dendrites and by-products, and its preparation method includes the following steps: S1. Add 1 g of sucralose and 1 g of hydroxypropyl distarch phosphate to 100 g of deionized water and dissolve by ultrasonic wave to obtain a mixed solution; the total addition concentration of the two additives in deionized water is 2 wt%; S2. Add 0.1 mol of zinc perchlorate (the addition 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 inhibiting dendrites and by-products.

[0024] Example 2 This example provides an aqueous zinc-ion battery electrolyte capable of inhibiting dendrites and by-products, and its preparation method includes the following steps: S1. Add 17.5 g of sucralose and 17.5 g of hydroxypropyl distarch phosphate to 100 g of deionized water and dissolve by ultrasonic wave to obtain a mixed solution; the total addition concentration of the two additives in deionized water is 35 wt%; S2. Add 0.05 mol of ZnSO4 (the addition concentration in deionized water is 0.5 mol / kg) to the mixed solution, stir evenly to obtain an aqueous zinc-ion battery electrolyte 2 that can inhibit dendrites and by-products.

[0025] Example 3 This example provides an aqueous zinc-ion battery electrolyte that can inhibit dendrites and by-products. Its preparation method includes the following steps: S1. Add 10 g of sucralose and 1 g of hydroxypropyl distarch phosphate to 100 g of deionized water and dissolve them by ultrasonic treatment to obtain a mixed solution; the total addition concentration of the two additives in deionized water is 11 wt%. S2. Add 0.3 mol of zinc perchlorate (the addition concentration in deionized water is 3 mol / kg) to the mixed solution, stir evenly to obtain an aqueous zinc-ion battery electrolyte 3 that can inhibit dendrites and by-products.

[0026] Example 4 This example provides an aqueous zinc-ion battery electrolyte that can inhibit dendrites and by-products. Its preparation method includes the following steps: S1. Add 1 g of sucralose and 10 g of hydroxypropyl distarch phosphate to 100 g of deionized water and dissolve them by ultrasonic treatment to obtain a mixed solution; the total addition concentration of the two additives in deionized water is 11 wt%. S2. Add 0.5 mol of zinc perchlorate (the addition concentration in deionized water is 5 mol / kg) to the mixed solution, stir evenly to obtain an aqueous zinc-ion battery electrolyte 4 that can inhibit dendrites and by-products.

[0027] Comparative Example 1 This comparative example provides an aqueous zinc-ion battery electrolyte. Its preparation method includes the following steps: S1. Add 5 g of sucralose to 100 g of deionized water and dissolve it by ultrasonic treatment. The dissolution concentration is 5 wt% to obtain a sucralose solution. S2. Add 0.1 mol of zinc perchlorate (the addition concentration in deionized water is 1 mol / kg) to the sucralose solution to obtain a common aqueous zinc-ion battery electrolyte 1.

[0028] Comparative Example 2 This example provides an aqueous zinc-ion battery electrolyte. Its preparation method includes the following steps: S1. Add 5 g of hydroxypropyl distarch phosphate to 100 g of deionized water and dissolve it by ultrasonic treatment. The dissolution concentration is 5 wt% to obtain a hydroxypropyl distarch phosphate solution. S2. Add 0.1 mol of zinc perchlorate (the addition concentration in deionized water is 1 mol / kg) to the hydroxypropyl distarch phosphate solution to prepare the electrolyte 2 of the ordinary aqueous zinc-ion battery.

[0029] Comparative Example 3 This example provides a pure zinc perchlorate electrolyte, and its preparation method includes the following steps: Add 0.2 mol of zinc perchlorate to 100 g of deionized water, with an addition concentration of 2 mol / kg, and ultrasonically dissolve it to prepare the electrolyte 3 of the ordinary aqueous zinc-ion battery without additives.

[0030] Performance test comparison: Figure 1 is the XRD pattern. Deposit the zinc sheet in the different electrolytes prepared in Example 1, Comparative Example 1, Comparative Example 2, and Comparative Example 3. Both the positive electrode and the negative electrode are zinc sheets. The specific test steps are as follows: At a current density of 10 mA / cm 2 , perform XRD testing on the positive electrode zinc sheet after discharging for 1 hour; it can be seen from Figure 1 that compared with the pure zinc perchlorate electrolyte (2 mol / kg, without additives) in Comparative Example 3 and the electrolyte only added with hydroxypropyl distarch phosphate in Comparative Example 2, the electrolyte containing sucralose in Example 1 shows obvious (002) crystal plane orientation growth, indicating that adding sucralose can induce the growth of (002) crystal plane texture and inhibit the growth of zinc dendrites.

[0031] Figure 2 Compare the cyclic stability performance of the Zn / / Zn battery. Assemble the different electrolytes prepared in Example 1, Comparative Example 1, Comparative Example 2, and Comparative Example 3 with the positive electrode (zinc sheet), separator (glass fiber), negative electrode (zinc sheet), gasket, and spring sheet into a zinc-zinc battery. The specific test steps are as follows: Apply a current of 20 mA cm -2 to the symmetric battery, record the change curve of the polarization voltage with time. Under the test conditions of 20 mA cm -2 -20 mAh cm -2 , compared with the pure zinc perchlorate electrolyte in Comparative Example 3 and the electrolytes only added with sucralose or hydroxypropyl distarch phosphate in Comparative Examples 1 and 2, the cyclic stability performance of the mixed additive system of sucralose and hydroxypropyl distarch phosphate is significantly improved.

[0032] Figure 3 Compare the Coulomb efficiency of the Zn / / Cu half-cell assembled with the different electrolytes prepared in Example 1, Comparative Example 1, Comparative Example 2, and Comparative Example 3. Assemble the aqueous zinc-ion battery electrolyte with the positive electrode (Cu sheet), separator (filter paper), negative electrode (zinc sheet), gasket, and spring sheet into a zinc-copper half-cell. Apply 0.5 mA cm -2The charge-discharge current, the discharge time is 60 minutes, the charging cut-off voltage is 0.5 V, and the change trend of the Coulomb efficiency with the number of cycles is recorded. From Figure 3 It can be seen that the average Coulomb efficiency of the Zn / / Cu half-cell containing sucralose and hydroxypropyl distarch phosphate additives is 99.4%, which is significantly higher than that of the pure zinc perchlorate electrolyte in Comparative Example 3 and the electrolytes containing only sucralose or hydroxypropyl distarch phosphate in Comparative Examples 1 and 2.

[0033] Figure 4 The cyclic stability performance of full cells assembled with different electrolytes prepared in Example 1 and Comparative Examples 1, 2, and 3 was compared. The positive electrode is NH4V4O 10 , the negative electrode is a zinc sheet, and the specific test steps are as follows: When the current density is 5 Ag -1 , the change trend of the specific capacity of the Zn / / NVO full cell with the number of cycles is recorded. As Figure 4 shown, the initial specific capacity of the electrolyte containing sucralose and hydroxypropyl distarch phosphate additives is as high as 301.72 mAh g -1 , and it still has a retention rate of 93% after 1000 cycles, indicating that the attenuation of the positive electrode specific capacity is slow, and the cyclic stability performance is significantly higher than that of the pure zinc perchlorate electrolyte in Comparative Example 3 and the electrolytes containing only sucralose or hydroxypropyl distarch phosphate in Comparative Examples 1 and 2.

[0034] The different electrolytes prepared in Examples 2, 3, and 4 were assembled with a positive electrode (zinc sheet), a separator (glass fiber), a negative electrode (zinc sheet), gaskets, and shrapnel into a Zn / / Zn symmetric cell. Under the test conditions of 20 mA cm -2 -20 mAh cm -2 , the Zn / / Zn symmetric cell can stably cycle for 60 hours, 86 hours, and 75 hours in sequence, which are all better than the pure zinc perchlorate electrolyte and the electrolytes containing only sucralose or hydroxypropyl distarch phosphate, confirming the effectiveness of the additives in the electrolytes of Examples 2, 3, and 4.

[0035] Those skilled in the art should understand that the above are only several specific embodiments of the present invention, rather than all embodiments. It should be pointed out that many modifications and improvements can be made for those of ordinary skill in the art. All modifications or improvements that do not exceed the scope of the claims should be regarded as the protection scope 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 addition concentration of the additive in the solvent is 2-35 wt%, and the addition concentration of the zinc salt in the solvent is 0.5-5 mol / kg.

2. The aqueous zinc ion battery electrolyte according to claim 1, wherein The mass ratio of 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, characterized in that, 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 1-4, characterized in that, It includes the following steps: adding sucralose and hydroxypropyl distarch phosphate into the solvent to dissolve, obtaining a mixed solution of sucralose and hydroxypropyl distarch phosphate, and then adding the zinc salt and stirring evenly to obtain an aqueous zinc-ion battery electrolyte.

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

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

8. The aqueous zinc-ion battery according to claim 7, wherein, The positive electrode is NH4V4O 10 or a Cu sheet.

9. The aqueous zinc-ion battery according to claim 7, characterized in that, The separator 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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