Low-cost and environment-friendly aqueous zinc ion battery electrolyte as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of new energy, particularly relates to the field of zinc ion batteries, and provides a low-cost and environment-friendly aqueous zinc ion battery electrolyte as well as a preparation method and application thereof. The low-cost aqueous zinc ion battery electrolyte comprises soluble zinc salt and an aluminum metal salt additive. The preparation method of the low-cost aqueous zinc ion battery electrolyte comprises the following steps: adding the aluminum metal salt additive into a soluble zinc salt solution, and uniformly stirring; according to the invention, the problems of uncontrollable dendritic crystal growth and irreversible side reaction in the application process of the zinc ion battery in the prior art are solved, so that the electrochemical performance of the zinc ion battery is improved.

Description

Technical Field

[0001] The present invention belongs to the field of new energy technology, and specifically provides a low-cost and environmentally friendly aqueous zinc ion battery electrolyte and a preparation method and application thereof. Background Art

[0002] Due to over-exploitation, energy shortage has become a major problem. The large-scale use of renewable energy is imminent, and the necessary energy storage system has also become urgent. For a long time, lithium-ion batteries have been responsible for this important task and constitute the first generation of energy storage elements. Lithium batteries have high energy density, low self-discharge rate and flat discharge voltage. However, over time, many problems have been found in current lithium batteries. Limited lithium resources, high cost, poor safety and environmental impact have hindered the large-scale application of lithium-ion batteries. More and more researchers are committed to finding green, safe, low-cost and high-performance secondary batteries that can replace lithium-ion batteries. Aqueous zinc (Zn) ion batteries (AZIBs) have a high theoretical capacity (820mAhg -1 and 5855mAhcm -3 ), low redox potential (-0.76V compared to the standard hydrogen electrode), resource abundance and environmental benefits, it is considered to be a promising alternative to lithium-ion batteries. Rechargeable aqueous zinc-ion batteries have the advantages of high safety, high energy density, green environmental protection, abundant material sources and affordable prices, so they have good application prospects.

[0003] However, the rugged surface of exposed zinc leads to uneven zinc nucleation and deposition, resulting in huge zinc dendrites that easily pierce the separator and cause short circuits. These problems seriously hinder the practical application of AZIBs. In order to solve the above-mentioned problems of zinc batteries, there have been many related studies, such as: zinc negative electrode surface modification, electrolyte modification, etc. Among them, the development of new electrolytes is an effective method. However, how to reduce costs while protecting the environment is the main direction of future research on zinc-ion battery electrolytes. Summary of the invention

[0004] The present invention aims at solving the problems existing in the application process of aqueous zinc ion batteries in the prior art, such as hydrogen evolution reaction, uncontrollable dendrite growth and irreversible side reactions, and provides a low-cost and environmentally friendly aqueous zinc ion battery electrolyte, a preparation method and an application thereof.

[0005] To achieve the above object, the technical solution adopted by the present invention is:

[0006] A low-cost and environmentally friendly aqueous zinc ion battery electrolyte, the electrolyte comprising a soluble zinc salt solution and an aluminum salt as additives.

[0007] Furthermore, in the above-mentioned low-cost and environmentally friendly aqueous zinc ion battery electrolyte, the soluble zinc salt is one or more of zinc sulfate, zinc chloride and zinc trifluoromethanesulfonate.

[0008] Furthermore, in the above-mentioned low-cost and environmentally friendly aqueous zinc ion battery electrolyte, the aluminum salt is one or both of aluminum chloride and aluminum sulfate.

[0009] Furthermore, in the above-mentioned low-cost and environmentally friendly aqueous zinc ion battery electrolyte, the aluminum salt is aluminum sulfate.

[0010] Furthermore, in the above-mentioned low-cost and environmentally friendly aqueous zinc ion battery electrolyte, the concentration of the soluble zinc salt in the electrolyte is 2 mol / L.

[0011] Furthermore, in the above-mentioned low-cost and environmentally friendly aqueous zinc ion battery electrolyte, the concentration of the aluminum salt in the electrolyte is 0.1-0.8 mol / L.

[0012] The method for preparing the low-cost and environmentally friendly aqueous zinc ion battery electrolyte described in any one of the above comprises the following steps: adding aluminum salt to a soluble zinc salt solution and stirring evenly.

[0013] Furthermore, in the above preparation method, the stirring time is 0.5-1h.

[0014] Application of any of the above-mentioned low-cost and environmentally friendly aqueous zinc ion battery electrolytes in zinc ion batteries.

[0015] Furthermore, in the above application, the zinc ion battery is an aqueous rechargeable zinc ion battery.

[0016] The present invention has the following beneficial effects:

[0017] 1. The present invention significantly improves the chemical properties of the electrolyte by adding a metal aluminum salt as an electrolyte additive in the electrolyte, and the electrolyte additive solves the problems of uncontrollable dendrite growth, irreversible side reactions and hydrogen evolution in zinc ion batteries. Specifically, the metal aluminum ions use their strong coordination ability to compete with zinc ions for coordinated water, accelerate the desolvation process of zinc, and thus facilitate the reduction of dendrites and the generation of by-products; at the same time, it helps zinc to deposit uniformly, so that it finally has excellent electrochemical stability.

[0018] 2. The metal aluminum sulfate additive used in the present invention has low cost, small addition amount, is easy to obtain, and only needs to be weighed, stirred and mixed according to a preset ratio. Therefore, the process operation is simple and easy. At the same time, the introduction of metal aluminum sulfate will not increase additional ionic impurities, and it is in line with environmental protection concepts and low in price. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is an optical photograph of the electrolyte prepared in Example 1.

[0020] Figure 2 This is an optical photograph of the electrolyte of Comparative Example 1.

[0021] Figure 3 This is a SEM image of a symmetrical battery assembled with a zinc sheet using the aqueous zinc ion battery electrolyte prepared in Example 1 after cycling for 30 cycles.

[0022] Figure 4 This is a SEM image of a symmetrical battery assembled with zinc sheets using the aqueous zinc ion battery electrolyte prepared in Comparative Example 1 after cycling for 30 cycles.

[0023] Figure 5 It is a comparison chart of the cyclability of symmetrical batteries assembled with the aqueous zinc ion battery electrolytes prepared in Example 1 and Comparative Example 1.

[0024] Figure 6 This is a practical picture of a soft-pack battery assembled with the aqueous zinc ion battery electrolyte prepared in Example 1. DETAILED DESCRIPTION

[0025] Example 1

[0026] A low-cost and environmentally friendly aqueous zinc ion battery electrolyte and a preparation method thereof, comprising the following steps:

[0027] Aluminum sulfate was added to 25 mL of 2 mol / L zinc sulfate electrolyte at a concentration of 0.015 M and stirred for 1 h to obtain a uniform electrolyte.

[0028] Comparative Example 1

[0029] A method for preparing an aqueous zinc ion battery electrolyte comprises the following steps:

[0030] 2 mol / L zinc sulfate was used as the electrolyte.

[0031] Figure 1 is an optical photograph of the electrolyte prepared in Example 1, Figure 2 It is an optical photograph of the electrolyte in Comparative Example 1, which shows that the prepared electrolyte is uniform and transparent.

[0032] Example 2

[0033] A low-cost and environmentally friendly aqueous zinc ion battery electrolyte and a preparation method thereof, comprising the following steps:

[0034] Aluminum sulfate was added to 25 mL of 2 mol / L zinc sulfate electrolyte at a concentration of 0.005 M and stirred for 1 h to obtain a uniform electrolyte.

[0035] Example 3

[0036] A low-cost and environmentally friendly aqueous zinc ion battery electrolyte and a preparation method thereof, comprising the following steps:

[0037] Aluminum sulfate was added to 25 mL of 2 mol / L zinc sulfate electrolyte at a concentration of 0.01 M and stirred for 1 h to obtain a uniform electrolyte.

[0038] Example 4

[0039] A low-cost and environmentally friendly aqueous zinc ion battery electrolyte and a preparation method thereof, comprising the following steps:

[0040] Aluminum sulfate was added to 25 mL of 2 mol / L zinc sulfate electrolyte at a concentration of 0.02 M and stirred for 1 hour, but it did not dissolve. This indicates that the zinc electrolyte with 0.02 M aluminum sulfate additive could not be successfully prepared.

[0041] Example 5

[0042] This embodiment provides the test method and results of the aqueous zinc ion battery electrolyte prepared in Example 1 and Comparative Example 1, which specifically includes the following steps:

[0043] Battery assembly: The aqueous zinc ion battery electrolyte prepared in Example 1 and Comparative Example 1 were assembled into a Zn-Zn symmetrical battery, using a Swagelok battery assembly device and a cellulose separator on a Newway test system. The cycle performance of the battery composed of Example 1 and Comparative Example 1 was tested, and the results are as follows: Figure 5 As shown, from Figure 5 It can be seen that the symmetrical battery with the electrolyte composition of Example 1 has stable cycle performance, and it is obvious that the symmetrical battery with the addition of aluminum sulfate has stable cycle performance.

[0044] Figure 3 This is a SEM image of zinc deposited on stainless steel in Example 1. The surface of the stainless steel is relatively flat, and no obvious zinc dendrites are observed, indicating that the addition of aluminum sulfate to the electrolyte can effectively inhibit the growth of zinc dendrites.

[0045] Figure 4 This is a SEM image of zinc deposited on stainless steel in Comparative Example 1. Large zinc dendrites are observed on the surface of the stainless steel over a large area of ​​the zinc sheet plane, indicating that the growth rate of zinc dendrites in the zinc sulfate electrolyte is relatively fast.

Claims

1. A low-cost and environmentally friendly aqueous zinc ion battery electrolyte, characterized in that: The electrolyte includes a soluble zinc salt solution and an aluminum salt as an additive.

2. A low-cost and environmentally friendly aqueous zinc ion battery electrolyte according to claim 1, characterized in that: The soluble zinc salt is one or more of zinc sulfate, zinc chloride and zinc trifluoromethanesulfonate.

3. A low-cost and environmentally friendly aqueous zinc ion battery electrolyte according to claim 1, characterized in that: The aluminum salt is one or both of aluminum chloride and aluminum sulfate.

4. A low-cost and environmentally friendly aqueous zinc ion battery electrolyte according to claim 3, characterized in that: The aluminum salt is aluminum sulfate.

5. A low-cost and environmentally friendly aqueous zinc ion battery electrolyte according to claim 1, characterized in that: The concentration of the soluble zinc salt in the electrolyte is 2 mol / L.

6. A low-cost and environmentally friendly aqueous zinc ion battery electrolyte according to claim 1, characterized in that: The concentration of the aluminum salt in the electrolyte is 0.1-0.8 mol / L.

7. The method for preparing a low-cost and environmentally friendly aqueous zinc ion battery electrolyte according to any one of claims 1 to 6, characterized in that: The method comprises the following steps: adding aluminum salt into a soluble zinc salt solution and stirring the solution evenly.

8. The preparation method according to claim 7, characterized in that: The stirring time is 0.5-1h.

9. Use of the low-cost and environmentally friendly aqueous zinc ion battery electrolyte according to any one of claims 1 to 6 in zinc ion batteries.

10. The use according to claim 9, characterized in that: The zinc ion battery is an aqueous rechargeable zinc ion battery.

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