A water-based zinc ion battery electrolyte containing a heparin sodium additive, a preparation method and application thereof

Abstract

The application provides a multifunctional heparin sodium additive, and creates a ternary synergistic electrolyte of "reconstructed hydrogen bond network-ion coordination-interface protection". The water-based zinc ion battery with high energy density and long service life is realized, and the problems such as zinc negative electrode dendrite growth, serious side reaction and unstable interface in the prior art are solved. The heparin sodium molecular structure is rich in sulfonic acid group functional groups, can be chemically adsorbed with the zinc surface, and effectively isolates the direct contact of the electrolyte with the zinc negative electrode. The negative charge group in the heparin sodium molecule can compete with the water molecules in [Zn (H2O) 6] 2+ for coordination, weaken the solvation structure of Zn 2+ , and promote the uniform deposition of Zn 2+ . The heparin sodium molecule can destroy the hydrogen bond network between water molecules, thereby inhibiting the occurrence of hydrogen evolution reaction. The addition of heparin sodium improves the service life of the battery, and the significant effectiveness in regulating zinc dendrite growth and inhibiting side reactions, which opens up a new path for the development of high-performance water-based zinc ion batteries.

Description

Technical Field

[0001] This invention relates to the field of aqueous zinc-ion battery technology, specifically creating a ternary synergistic electrolyte of "reconstructed hydrogen bond network-ion coordination-interface protection" to achieve high energy density and long lifespan aqueous zinc-ion batteries. Background Technology

[0002] Aqueous zinc-ion batteries have become a strong candidate for large-scale energy storage systems due to their high safety, low cost, and environmental friendliness. However, zinc anodes face problems such as dendrite growth, hydrogen evolution side reactions, and interface instability in practical applications, which seriously affect the cycle life and safety of the battery. While existing technologies can alleviate these problems to some extent through surface coatings and electrolyte additives, they still suffer from drawbacks such as complex processes, high costs, and limited functionality. Therefore, developing a simple, efficient, and multifunctional additive is of great significance for zinc anode protection strategies. Trifunctional heparin sodium additives can chemically adsorb onto the zinc surface, forming a dense and uniform protective film that effectively isolates the electrolyte from direct contact with the zinc anode and suppresses side reactions. The negatively charged groups in the heparin sodium molecule can react with [Zn(H₂O)₆]. 2+ Competitive coordination of water molecules in Zn weakens 2+ The solvation structure lowers the desolvation energy barrier and promotes Zn 2+ Uniform deposition. Sodium heparin molecules can insert between water molecules, disrupting the hydrogen bond network between water molecules, reducing the activity of water, and thus inhibiting the hydrogen evolution reaction. Summary of the Invention

[0003] The present invention aims to provide an aqueous zinc-ion battery electrolyte containing heparin sodium additive, its preparation method and application, to solve the problems of severe dendrite growth, intense hydrogen evolution side reaction and interface instability in the prior art.

[0004] Preferably, the mass fraction of the heparin sodium additive is 0.7%.

[0005] The preparation method of the heparin sodium trifunctional additive includes the following steps: dissolving zinc sulfate heptahydrate in deionized water and stirring with a magnetic stirrer for 30 min at room temperature to prepare a 2.0 M pure zinc sulfate electrolyte. For the electrolyte containing heparin sodium, adding different mass fractions of heparin sodium powder to the 2.0 M zinc sulfate electrolyte and stirring with a magnetic stirrer for 30 min at room temperature to prepare an electrolyte containing heparin sodium additive.

[0006] The present invention provides a trifunctional heparin sodium additive as described in the above technical solution or a preparation method described in the above technical method, which shows significant effectiveness of the trifunctional heparin sodium additive in regulating zinc dendrite formation and inhibiting the formation of by-products in batteries.

[0007] This invention provides an aqueous zinc-ion battery electrolyte containing heparin sodium additive and its preparation method, solving problems such as dendrite growth, severe side reactions, and interface instability in existing technologies. The heparin sodium provided by this invention, under room temperature (25°C), forms a stable inorganic SEI protective film in situ on the zinc anode surface by introducing heparin sodium as a trifunctional additive into the aqueous electrolyte. The heparin sodium molecule is rich in polar functional groups such as carboxyl and sulfonic acid groups, which can chemically adsorb onto the zinc surface to form a dense and uniform protective film, effectively isolating the electrolyte from direct contact with the zinc anode and suppressing side reactions. The negatively charged groups in the heparin sodium molecule can react with [Zn(H₂O)₆]. 2+ Water molecules compete for coordination, disrupting Zn 2+ The solvation structure lowers the desolvation energy barrier and promotes Zn 2+ Uniform deposition. Sodium heparin molecules can insert between water molecules, disrupting the hydrogen bond network between water molecules, reducing the activity of water, and thus inhibiting the hydrogen evolution reaction. The addition of sodium heparin significantly improves the battery's lifespan and exhibits faster Zn deposition. 2+ The significant effectiveness of deposition kinetics in regulating zinc dendrite growth and suppressing side reactions opens up new avenues for the development of high-performance aqueous zinc-ion batteries.

[0008] Compared with existing technologies, this invention has the following advantages: Multifunctional integration: A single additive achieves three major functions: protective film formation, solvation regulation, and hydrogen bond disruption. Simple process: Can be prepared at room temperature without complex equipment. Low cost: Heparin sodium is a commercially available common biological polysaccharide with wide availability. Environmentally friendly: Aqueous system, non-toxic and harmless. Excellent performance: Cycle life is increased by more than 43 times, and dendrite inhibition effect is significant. Attached Figure Description

[0009] Figure 1 The image shows a scanning electron microscope image of the trifunctional heparin sodium additive and the basic zinc sulfate electrolyte prepared in Example 1, after the zinc sheet was soaked in the electrolyte for 5 days.

[0010] Figure 2 XRD pattern of an aqueous zinc-ion battery prepared using the trifunctional heparin sodium additive and basic zinc sulfate electrolyte of Example 1 after 200 hours of use.

[0011] Figure 3 The graph shows the results of a chronoamperometry test on an aqueous zinc-ion battery made from the trifunctional heparin sodium additive prepared in Example 1 and the basic zinc sulfate electrolyte.

[0012] Figure 4Scanning electron microscope image of an aqueous zinc-ion battery prepared using the trifunctional heparin sodium additive and basic zinc sulfate electrolyte of Example 1 after 200 hours of cycling.

[0013] Figure 5 Impedance diagrams of aqueous zinc-ion batteries prepared using the trifunctional heparin sodium additive and basic zinc sulfate electrolyte prepared in Examples 1, 2-3.

[0014] Figure 6 Example 1 shows the long-cycle results of an aqueous zinc-zinc symmetric battery using the prepared trifunctional heparin sodium additive and the basic electrolyte zinc sulfate, with a current density of 1 mA·cm⁻¹. -2 .

[0015] Figure 7 Example 1 shows the long-cycle results of a zinc-copper half-cell aqueous zinc-ion battery prepared using the trifunctional heparin sodium additive and the basic electrolyte zinc sulfate, with a current density of 1 mA·cm⁻¹. -2 .

[0016] Figure 8 Example 1 shows a comparison of the capacity stability of a zinc-vanadium battery prepared using the trifunctional heparin sodium additive and the basic electrolyte zinc sulfate, with a current density of 3 A / g. Detailed Implementation

[0017] The preparation method of the trifunctional heparin sodium additive of the present invention includes the following steps: dissolving zinc sulfate heptahydrate in deionized water and stirring with a magnetic stirrer for 30 min at room temperature to prepare 2.0 M pure zinc sulfate electrolyte. For electrolytes containing heparin sodium, different amounts of heparin sodium powder are added to the 2.0 M zinc sulfate electrolyte, with the optimal concentration being 0.7%.

[0018] In this invention, unless otherwise specified, all raw material components are commercially available products well known to those skilled in the art.

[0019] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the protection scope of this invention. Example

[0020] Prepare 20 mL of 2 M ZnSO4 aqueous electrolyte, add 0.7% heparin sodium by mass, and stir until completely dissolved.

[0021] Trifunctional heparin sodium additives were prepared according to the method in Example 1, and the preparation conditions are shown in Table 1: Table 1. Preparation conditions for Examples 1-4 Example Zinc sulfate heptahydrate Heparin sodium concentration Deionized water Example 1 11.502g 80.514mg 0.7% 20mL Example 2 11.502g 11.502mg 0.1% 20mL Example 3 11.502g 161.028mg 1.4% 20mL Example 4 11.502g 230.04mg 2% 20mL

[0022] Document "X. Li, L. Wang, Y. Fu, H. Dang, D. Wang, F. Ran, Optimization strategies toward advanced aqueous zinc-ion batteries: from facing key issues to viable solutions, Nano Energy 116 (2023) 108858, https: / / doi.org / 10.1016 / j. nanoen.2023.108858."

[0023] Document "D. Bi, T. Zhao, Q. Lai, J. Zhao, S. Grigoriev, Y. liang, J.Alloy. Compd. 2024, 1002, 175448."

[0024] Document "V. Aupama, J. Sangsawang, W. Kao-ian, S. Wannapaiboon, J.Pimoei, Y. Warunyoo, M. Opchoei, Z. Tehrani, S. Margadonna, S. Kheawhom,Electrochim. Acta 2024, 506, 145059."

[0025] Figure 1 This is a scanning electron microscope image of zinc sheets immersed in trifunctional heparin sodium additive, prepared in Example 1. Figure 1 It can be seen that the trifunctional heparin sodium additive prepared after soaking for 5 days has good anti-corrosion properties.

[0026] Figure 2 XRD pattern of an aqueous zinc-ion battery after 200 hours of use with the trifunctional heparin sodium additive prepared in Example 1. Figure 2 It can be seen that no byproduct peaks appeared, and they preferentially deposited on the 002 crystal plane. This phenomenon indicates that the trifunctional heparin sodium additive can effectively inhibit the occurrence of side reactions, showing good stability and inhibition performance.

[0027] Figure 3 Scanning electron microscope image of an aqueous zinc-ion battery prepared using the trifunctional heparin sodium additive of Example 1 after 200 hours of cycling. Figure 3 It can be seen that after 200 hours of cycling test, the zinc anode surface with added heparin sodium additive was smooth, which successfully suppressed the formation of by-products and showed excellent stability.

[0028] Figure 4 The results of chronoamperometry tests were performed on aqueous zinc-ion batteries and basic electrolyte zinc-ion batteries using the trifunctional heparin sodium additive prepared in Example 1. Figure 4 It can be seen that for the zinc electrode, there is a continuous increase in current from the initial current to the final current within 200s, while the current of the aqueous zinc-ion battery with trifunctional heparin sodium additive only gradually stabilizes from the initial current in a very short time. This indicates that the aqueous zinc-ion battery with trifunctional heparin sodium additive undergoes rapid 3D diffusion, the process is diffusion-controlled, effectively suppressing side reactions such as hydrogen evolution, and resulting in more uniform zinc ion deposition.

[0029] Figure 5 The graph shows the results of cycle resistance tests on aqueous zinc-ion batteries and basic electrolyte zinc-ion batteries prepared with different concentrations of the trifunctional heparin sodium additive in Example 1. Figure 5 It can be seen that aqueous zinc-ion batteries based on trifunctional heparin sodium additives exhibit lower charge transfer resistance, which is superior to basic electrolyte zinc-ion batteries.

[0030] The performance of an aqueous zinc-ion battery made with the experimentally obtained trifunctional heparin sodium additive and a zinc-ion battery made with the basic electrolyte were tested in a Blue Electric system. The test results are as follows: Figures 6-8 As shown.

[0031] Figure 6 The graph shows the long-cycle results of an aqueous zinc-ion battery using the trifunctional heparin sodium additive prepared in Example 1. Figure 6 It can be seen that when the concentration of trifunctional heparin sodium additive is 0.7%, the cycle life of the battery is significantly extended, the electrochemical performance is greatly improved, and it exhibits superior overall performance.

[0032] Figure 7 This is a long-cycle diagram of an aqueous zinc-copper half-cell using the prepared trifunctional heparin sodium additive, as shown in Example 1. Figure 7 It can be seen that the zinc-vanadium battery using trifunctional heparin sodium additive exhibits excellent coulombic efficiency, with an efficiency of up to 99.58%, which is significantly better than the 99.09% efficiency of the basic electrolyte battery.

[0033] Figure 8 A comparison chart of the capacity stability of zinc-vanadium batteries made with the trifunctional heparin sodium additive prepared in Example 1 and the basic electrolyte is shown. Figure 8It can be seen that zinc-vanadium batteries using trifunctional heparin sodium additives exhibit excellent capacity stability, with a capacity retention rate of up to 90.6%, which is significantly better than the 33.6% capacity retention rate of ordinary zinc-vanadium batteries.

[0034] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. An aqueous zinc-ion battery electrolyte, characterized in that, This includes an aqueous zinc salt solution and a heparin sodium additive dissolved in it.

2. The aqueous zinc-ion battery electrolyte according to claim 1, characterized in that, The mass fraction of the heparin sodium additive is 0.1% to 3% based on the total mass of the electrolyte.

3. The aqueous zinc-ion battery electrolyte according to claim 2, characterized in that, The optimal mass fraction of heparin sodium is 0.7%.

4. The aqueous zinc-ion battery electrolyte according to claim 1, characterized in that, The zinc salt in the aqueous zinc salt solution is selected from at least one of zinc sulfate, zinc trifluoromethanesulfonate, zinc chloride, zinc perchlorate, and zinc acetate.

5. The aqueous zinc-ion battery electrolyte according to claim 4, characterized in that, The molar concentration of the zinc salt in the electrolyte is 1.0 M to 4.0 M.

6. The method for preparing the aqueous zinc-ion battery electrolyte according to any one of claims 1 to 5, characterized in that, First, zinc salt is dissolved in deionized water to obtain a basic electrolyte solution. Then, sodium heparin is added to the basic electrolyte solution and stirred to obtain the aqueous zinc-ion battery electrolyte.

7. The preparation method according to claim 6, characterized in that, The stirring described herein shall be carried out at room temperature for 10 min to 60 min.

8. An aqueous zinc-ion battery, characterized in that, It includes a positive electrode, a zinc negative electrode, and an aqueous zinc-ion battery electrolyte as described in any one of claims 1 to 5.

9. The aqueous zinc-ion battery according to claim 8, characterized in that, The battery is a symmetrical battery, a zinc-copper half-cell, or a zinc-ion full cell; the positive electrode material of the full cell includes manganese oxide, vanadium oxide, or a Prussian blue analogue.

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