Aqueous zinc ion battery electrolyte and preparation method and application thereof

Abstract

The invention discloses an aqueous zinc ion battery electrolyte and a preparation method and application thereof, and belongs to the field of aqueous zinc ion batteries. The aqueous zinc ion battery electrolyte comprises a two-effect additive, zinc salt and water, the two-effect additive comprises a polar group with a dipole effect and a hydrophobic carbocyclic group with a steric hindrance effect; the polar group is selected from at least one of a phosphate group, an ether group and a nitrogen group; and the hydrophobic carbocyclic group is selected from four-membered to eight-membered carbocyclic rings. The organic compound additive with both the steric hindrance effect and the dipole effect has various dipole groups combined with zinc ions and has the adsorption characteristic on a zinc negative electrode, so that a high-speed channel for transferring the zinc ions is constructed in a solution, rapid and uniform deposition of the zinc ions is realized, interfacial active water is repelled, and the zinc negative electrode is formed. Therefore, the dynamics and corrosion resistance of the battery are improved.

Description

Technical Field

[0001] This application relates to an aqueous zinc-ion battery electrolyte, its preparation method, and its application, belonging to the field of aqueous zinc-ion batteries. Background Technology

[0002] Due to the inherent safety, cost-effectiveness, and environmental compatibility of aqueous zinc-ion batteries, the global demand for sustainable energy storage systems is constantly growing, prompting in-depth research into aqueous zinc-ion batteries. The metallic zinc anode possesses a low redox potential (-0.76V vs. SHE) and a high theoretical capacity (820mAh g / g). -1 While possessing inherent advantages, the application of aqueous zinc-ion batteries remains hampered by ongoing challenges: anodic corrosion, dendrite growth, and irreversible byproduct formation. These issues collectively reduce cycle stability and coulombic efficiency, fundamentally limiting the deployment of aqueous zinc-ion batteries. Of particular concern is the spontaneous corrosion behavior involving the hydrogen evolution reaction, which persists throughout battery operation and becomes especially severe during long-term aging. This corrosion process leads to irreversible depletion of active materials and electrolytes, ultimately manifesting as accelerated capacity decay and detrimental calendar aging characteristics.

[0003] To achieve high durability in aqueous zinc-ion batteries, extensive research has been conducted on electrolyte and electrode modification. Strategies for optimizing aqueous electrolyte systems include organic co-solvents, high-concentration electrolytes, and functional additives. However, high-concentration electrolytes are limited in practical application due to their high cost and viscosity, and also suffer from increased dissolution barriers, degraded charge transfer kinetics, and reduced safety (e.g., flammability). Electrode modification techniques (such as artificial coatings) can improve battery kinetic performance and cycle stability; however, at high current densities, excessive zinc deposition can cover the modified electrode surface, weakening or even eliminating the protective effect of the artificial film. Furthermore, these processes are complex and costly, making them unsuitable for large-scale applications. In contrast, electrolyte additives that can form an interfacial protective layer in situ are considered a convenient and efficient method due to their simplicity, low cost, and excellent performance. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides an aqueous zinc-ion battery electrolyte comprising a two-effect additive, a zinc salt, and water. The two-effect additive includes steric hindrance effect groups and dipole effect groups. The dipole effect of the two-effect additive enables multi-site zinc ion coordination and strong adsorption to the zinc anode, thereby establishing a bridging channel for the zinc ion transport network at the electrolyte-electrode interface. Simultaneously, the steric hindrance effect of the two-effect additive reduces coordinated water molecules and forms a dehydrated interface layer, thus synergistically enhancing anti-aging capabilities and high-rate performance.

[0005] According to the first aspect of this application, an aqueous zinc-ion battery electrolyte is provided. The two-effect additive used is a high topological polarity surface area additive, including high steric hindrance groups and dipole interaction groups. This achieves both resistance to interfacial corrosion and rapid, stable zinc ion mass transfer.

[0006] An aqueous zinc-ion battery electrolyte, the aqueous zinc-ion battery electrolyte comprising a two-effect additive, a zinc salt and water;

[0007] The dual-effect additives include polar groups with dipole effects and hydrophobic carbocyclic groups with steric hindrance effects.

[0008] The polar group is selected from at least one of phosphate groups, ether groups, and nitrogen groups;

[0009] The hydrophobic carbocyclic group is selected from quaternary to octagonal carbocyclic rings.

[0010] Optionally, the aqueous zinc-ion battery electrolyte is composed of a two-effect additive, zinc salt, and water.

[0011] Polar groups such as phosphate groups, ether groups, and nitrogen groups are dipole interaction groups. Hydrophobic carbocyclic groups, ranging from four to eight members, are highly sterically hindered groups. This type of organic compound additive, which combines steric hindrance and dipole effects, possesses multiple dipole groups that bind to zinc ions and exhibit adsorption properties on the zinc anode. This allows for the construction of high-speed channels for zinc ion transfer in solution, achieving rapid and uniform zinc ion deposition, repelling interfacial active water, and thus improving the battery's kinetics and corrosion resistance.

[0012] The hydrophobic carbocyclic group is selected from four-membered rings, five-membered rings, six-membered rings, seven-membered rings, or eight-membered rings.

[0013] Preferably, the hydrophobic carbocyclic group is a five-membered ring or a six-membered ring.

[0014] Specifically, the hydrophobic carbocyclic group is a six-membered ring.

[0015] Optionally, the dual-effect additive is tris(4-morpholino)phosphine oxide.

[0016] Specifically, the structural formula of tris(4-morpholino)phosphine oxide is as follows:

[0017]

[0018] Optionally, the zinc salt is selected from at least one of zinc sulfate and zinc trifluoromethanesulfonate.

[0019] Optionally, the concentration of the two-effect additive is 1–20 mmol / L.

[0020] Optionally, the concentration of the two-effect additive is 5–15 mmol / L.

[0021] Optionally, the concentration of the two-effect additive is selected from any value or a range between 1 mol / L, 2 mol / L, 4 mol / L, 6 mol / L, 8 mol / L, 10 mol / L, 12 mol / L, 14 mol / L, 16 mol / L, 18 mol / L, and 20 mol / L.

[0022] Optionally, the concentration of the zinc salt is 1 to 3 mol / L.

[0023] Optionally, the concentration of the zinc salt is 1.5 to 2.5 mol / L.

[0024] Optionally, the concentration of the zinc salt is selected from any value or a range between 1 mol / L, 1.25 mol / L, 1.5 mol / L, 2 mol / L, 2.25 mol / L, 2.5 mol / L, 2.75 mol / L, and 3 mol / L.

[0025] According to a second aspect of this application, a method for preparing an aqueous zinc-ion battery electrolyte is provided.

[0026] The preparation method of the aqueous zinc-ion battery electrolyte described above includes: mixing a two-effect additive, a zinc salt, and water to obtain the aqueous zinc-ion battery electrolyte.

[0027] According to a third aspect of this application, an aqueous zinc-ion battery is provided.

[0028] An aqueous zinc-ion battery, the aqueous zinc-ion battery comprising a positive electrode, a negative electrode, a separator, and an electrolyte;

[0029] The electrolyte is selected from the aqueous zinc-ion battery electrolyte described above.

[0030] This invention significantly improves the cycle stability and corrosion resistance of aqueous zinc-ion batteries by adding trace amounts of tris(4-morpholinyl)phosphine oxide additive. The dipole interaction properties of this organic compound additive promote zinc ion coordination and strong adsorption to the zinc electrode, thereby bridging the channels for zinc ion migration within the solvation-interface network. Furthermore, the steric hindrance of the additive disrupts the primary solvation sheath layer of zinc ions, leading to the formation of a water molecule repulsion interfacial layer and suppressing side reactions. The additive can also adsorb onto the zinc metal surface, promoting the formation of a solid electrolyte interfacial phase protective layer on the electrode surface, improving the battery interface corrosion resistance and exhibiting excellent rate performance, which is of great significance for commercial applications.

[0031] According to a fourth aspect of this application, an electrical appliance is provided.

[0032] An electrical device comprising the aforementioned aqueous zinc-ion battery.

[0033] The beneficial effects that this application can produce include:

[0034] The aqueous zinc-ion battery electrolyte, its preparation method, and its application provided in this application have the following advantages:

[0035] (1) The phosphate, ether and nitrogen groups of the two-effect additives have a strong binding and coordination ability to zinc ions, which improves the mass transfer kinetics of zinc ions.

[0036] (2) The dual-effect additive has a strong adsorption effect on the metal Zn electrode and can form a solid electrolyte phase protective layer with organic and inorganic components, suppressing the side reaction at the electrode interface and realizing the electrode's anti-calendar aging performance.

[0037] In summary, this organic compound additive, which combines steric hindrance and dipole effects, possesses multiple dipole groups that bind to zinc ions and exhibits adsorption properties on the zinc anode. This allows for the construction of high-speed channels for zinc ion transport in solution, enabling rapid and uniform zinc ion deposition, while repelling interfacial active water, thereby improving the battery's kinetics and corrosion resistance. Adding trace amounts of tris(4-morpholino)phosphine oxide to the electrolyte of aqueous zinc-ion batteries can significantly improve their cycle resistance to calendar aging and high-rate performance, which is of great significance for commercial applications. Attached Figure Description

[0038] Figure 1 The rate polarization curves of Zn||Zn symmetric cells using the electrolyte in Example 2 and the electrolyte in Comparative Example 1 are shown.

[0039] Figure 2 It uses the electrolyte from Example 2 and the electrolyte from Comparative Example 1. 10 Charge / discharge specific capacity-cycle count curve of the full battery. Detailed Implementation

[0040] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.

[0041] Unless otherwise specified, all raw materials used in the embodiments of this application were purchased through commercial channels.

[0042] Unless otherwise specified, all test methods are standard and all instrument settings are those recommended by the manufacturer.

[0043] Example 1

[0044] Preparation of the test electrolyte: The concentration of the aqueous zinc-ion battery electrolyte additive in the electrolyte is 5 mmol / L. Tris(4-morpholino)phosphine oxide is added to a 2 mol / L aqueous solution of zinc trifluoromethanesulfonate. The solution is stirred thoroughly until the tris(4-morpholino)phosphine oxide is completely dissolved. After standing, an aqueous zinc-ion battery electrolyte is obtained.

[0045] Example 2

[0046] Preparation of the test electrolyte: The concentration of the aqueous zinc-ion battery electrolyte additive in the electrolyte is 10 mmol / L. Tris(4-morpholino)phosphine oxide is added to a 2 mol / L aqueous solution of zinc trifluoromethanesulfonate. The mixture is stirred thoroughly until the tris(4-morpholino)phosphine oxide is completely dissolved. After standing, an aqueous zinc-ion battery electrolyte is obtained.

[0047] Example 3

[0048] Preparation of the test electrolyte: The concentration of the aqueous zinc-ion battery electrolyte additive in the electrolyte is 20 mmol / L. Tris(4-morpholino)phosphine oxide is added to a 2 mol / L aqueous solution of zinc trifluoromethanesulfonate. The solution is stirred thoroughly until the tris(4-morpholino)phosphine oxide is completely dissolved. After standing, an aqueous zinc-ion battery electrolyte is obtained.

[0049] Comparative Example 1

[0050] The electrolyte of this comparative example aqueous zinc-ion battery is composed of inorganic salts, specifically a 2 mol / L aqueous solution of zinc trifluoromethanesulfonate.

[0051] The above-described Example 2 and Comparative Example 1 were applied to a zinc-zinc symmetrical battery, using 1 mA / cm 2 The deposition capacity was tested at gradient-incrementing current density rates. Their respective electrochemical performance is as follows: Figure 1 As shown, when the current density reaches 200 mA / cm² 2 In Comparative Example 1, a short circuit occurred; while in Example 2, which used the additive, the current density that could withstand was as high as 280 mA / cm². 2 Its high-rate performance is significantly better than that of Comparative Example 1.

[0052] The above-described Example 2 and Comparative Example 1 were applied to the assembly of aqueous zinc-ion full cells: NH4V4O synthesized by hydrothermal method was used... 10Powder, commercial conductive carbon (Superp), and commercial binder (PVDF) were mixed uniformly in a mass ratio of 7:2:1, and NMP was added to prepare a slurry. This slurry was then dripped onto carbon cloth and dried to obtain the positive electrode sheet. The positive electrode was assembled in the following order: positive electrode shell, positive electrode sheet, separator, electrolyte, negative electrode sheet, gasket, spring sheet, and negative electrode shell. The battery was then compacted using a pressing machine to obtain an aqueous zinc-ion battery. The assembled battery was charged and discharged at a high current density of 5 A / g. Their respective electrochemical performances are as follows: Figure 2 As shown, after 20 days of static aging, the cycle life of the full cell using the electrolyte of Example 2 is significantly higher than that of the full cell of Comparative Example 1.

[0053] As can be seen from the above embodiments, the method of the present invention has simple preparation steps and is of great significance for improving the cycle stability, kinetic performance, and corrosion inhibition of aqueous zinc-ion batteries, as well as for their large-scale industrial production.

[0054] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. An aqueous zinc-ion battery electrolyte, characterized in that, The aqueous zinc-ion battery electrolyte comprises a two-effect additive, zinc salt, and water; The dual-effect additives include polar groups with dipole effects and hydrophobic carbocyclic groups with steric hindrance effects. The polar group is selected from at least one of phosphate groups, ether groups, and nitrogen groups; The hydrophobic carbocyclic group is selected from quaternary to octagonal carbocyclic rings.

2. The aqueous zinc-ion battery electrolyte according to claim 1, characterized in that, The dual-effect additive is tris(4-morpholino)phosphine oxide.

3. The aqueous zinc-ion battery electrolyte according to claim 1, characterized in that, The zinc salt is selected from at least one of zinc sulfate and zinc trifluoromethanesulfonate.

4. The aqueous zinc-ion battery electrolyte according to claim 1, characterized in that, The concentration of the two-effect additive is 1–20 mmol / L.

5. The aqueous zinc-ion battery electrolyte according to claim 1, characterized in that, The concentration of the two-effect additive is 5–15 mmol / L.

6. The aqueous zinc-ion battery electrolyte according to claim 1, characterized in that, The concentration of the zinc salt is 1–3 mol / L.

7. The aqueous zinc-ion battery electrolyte according to claim 1, characterized in that, The concentration of the zinc salt is 1.5–2.5 mol / L.

8. The method for preparing the aqueous zinc-ion battery electrolyte according to any one of claims 1 to 7, characterized in that, The preparation method includes: mixing a two-effect additive, a zinc salt, and water to obtain the aqueous zinc-ion battery electrolyte.

9. An aqueous zinc-ion battery, characterized in that, The aqueous zinc-ion battery includes a positive electrode, a negative electrode, a separator, and an electrolyte; The electrolyte is selected from the aqueous zinc-ion battery electrolyte according to any one of claims 1 to 7.

10. An electrical appliance, characterized in that, The electrical equipment includes the aqueous zinc-ion battery as described in claim 9.

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