Aqueous zinc battery electrolyte system for high current density condition and application of aqueous zinc battery electrolyte system

Abstract

The invention relates to the technical field of electrochemical energy storage, in particular to an aqueous zinc battery electrolyte system for a high-current-density condition and application of the aqueous zinc battery electrolyte system. The aqueous zinc battery electrolyte system comprises zinc salt and a first organic additive, the first organic additive comprises 1, 4-butynediol. According to the electrolyte system with the 1, 4-butynediol as the main interface regulation component and the application of the electrolyte system, hydroxyl and acetylenic bonds in 1, 4-butynediol molecules can act on a water molecule hydrogen bond network and the surface of metal zinc in a synergistic mode, the crystal face orientation and interface reaction kinetics of zinc deposition are regulated and controlled, therefore, disordered growth of zinc dendrites is inhibited, and the service life of the electrolyte system is prolonged. And a uniform and compact deposition layer is obtained.

Description

An aqueous zinc battery electrolyte system for high current density conditions and its application Technical Field

[0001] This invention relates to the field of electrochemical energy storage technology, specifically to an aqueous zinc battery electrolyte system for high current density conditions and its application. Background Technology

[0002] Aqueous zinc-ion batteries have broad application prospects in large-scale energy storage due to their low cost, high safety, and environmental friendliness. However, under high current density conditions, the metallic zinc anode still faces a series of key technical problems during repeated deposition / stripping, mainly manifested as uneven zinc deposition, dendrite growth, and accompanying side reactions such as hydrogen evolution. These problems can lead to increased battery polarization, decreased coulombic efficiency, and even membrane puncture and internal short circuits during long-term cycling, severely limiting the stable operation of aqueous zinc batteries under high-rate conditions.

[0003] To address these issues, existing technologies primarily focus on artificially coating the zinc anode surface or optimizing zinc deposition behavior through electrolyte optimization strategies. Among these, introducing organic additives into the electrolyte has attracted widespread attention due to its simple process and strong compatibility. Previous studies have shown that some small molecules containing hydroxyl groups or polar functional groups can reduce the activity of free water by forming hydrogen bonds with water molecules, thereby mitigating hydrogen evolution reactions to some extent and improving zinc deposition morphology. However, existing additive systems still suffer from insufficient interface control and unstable deposition orientation under high current density conditions, making it difficult to simultaneously achieve dendrite suppression and long-term cycling stability.

[0004] Against this backdrop, developing a functional organic molecule capable of simultaneously acting on the hydrogen bond network of water molecules and the surface of metallic zinc has become a key direction for improving the high current density performance of aqueous zinc batteries. An ideal additive molecule should possess good solubility in aqueous solutions, be able to selectively adsorb at the zinc anode interface, and guide the uniform nucleation and orderly growth of zinc without significantly increasing the risk of side reactions.

[0005] 1,4-Butynediol (BTDA) is a small organic molecule containing both hydroxyl (-OH) and alkyne bonds (-C≡C-). Its molecular structure allows it to interact with water molecules via hydrogen bonds through its hydroxyl groups, and also to undergo directional adsorption onto metal surfaces through its unsaturated bond structure. Therefore, this invention provides an aqueous zinc battery electrolyte system for high current density conditions and its application. Summary of the Invention

[0006] The purpose of this invention is to provide an aqueous zinc battery electrolyte system and its application under high current density conditions, to solve the problems of dendrite growth, increased interface polarization, and insufficient cycle stability caused by uneven zinc deposition in existing aqueous zinc batteries during high current density charge and discharge processes. This is especially true at ≥10 mA·cm⁻¹. -2 Under high current density conditions, traditional aqueous zinc battery electrolyte systems cannot simultaneously ensure the uniformity of zinc deposition and interface stability. They are prone to dendrite piercing the separator and internal short circuits during long-term cycling, which severely restricts their application in high-rate energy storage scenarios.

[0007] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: In a first aspect, the present invention provides an aqueous zinc battery electrolyte system for high current density conditions, the aqueous zinc battery electrolyte system comprising: zinc salt and a first organic additive; the first organic additive comprises 1,4-butynediol.

[0008] Furthermore, the molar ratio of the 1,4-butynediol to the zinc salt is 1 × 10⁻⁶. -4 ~5×10 -2 ∶1.

[0009] Furthermore, the molar ratio of the 1,4-butynediol to the zinc salt is 2 × 10⁻⁶. -3 ~1×10 -2 ∶1.

[0010] Furthermore, the aqueous zinc battery electrolyte system also includes an aqueous solvent.

[0011] The zinc salt can be a commonly used zinc salt in aqueous zinc batteries in this field, including but not limited to zinc sulfate, zinc chlorate, etc.; other water-soluble zinc salts can also be used; preferably zinc sulfate, the concentration of which can be 0.1 M to 5.0 M, 1 M to 3 M is a commonly used concentration range in this field, lower or higher concentrations are used to cover different conductivity requirements and experimental conditions, without affecting the realization of the interface regulation mechanism described in this invention.

[0012] The first organic additive includes 1,4-butynediol, wherein the 1,4-butynediol is introduced into the electrolyte system in an ultra-low concentration form, and its concentration in the electrolyte is preferably 1 mM to 20 mM, more preferably about 5 mM.

[0013] This invention reveals that 1,4-butynediol molecules simultaneously contain hydroxyl (–OH) and alkyne (–C≡C–) structures. In aqueous solution, it can interact with water molecules through hydrogen bonds formed by the hydroxyl groups, thus regulating the hydrogen bond network structure of water molecules in the electrolyte. Simultaneously, the alkyne bond structure facilitates directional adsorption of the molecule on the zinc surface. Under these synergistic effects, 1,4-butynediol can induce uniform nucleation and orderly growth of zinc ions at the zinc anode interface, preferentially guiding zinc deposition along the Zn(002) crystal plane, thereby forming a dense and smooth zinc deposition layer and effectively suppressing disordered dendrite growth. Furthermore, the introduction of 1,4-butynediol can reduce the proportion of active water molecules at the interface, suppressing side reactions such as hydrogen evolution, stabilizing the electrode / electrolyte interface structure, and improving the reversibility of the zinc deposition / stripping process. Further research shows that the amount of 1,4-butynediol added to the electrolyte has a significant impact on the interface regulation effect.

[0014] When 1,4-butynediol is introduced into the electrolyte system at a low concentration of about 5 mM, it forms a stable and continuous adsorption regulation layer on the surface of the zinc anode, which can effectively suppress dendrite growth and maintain long-term cycling stability under high current density conditions.

[0015] When the concentration of 1,4-butynediol is further increased (e.g., about 10 mM), it can still achieve the zinc deposition / stripping process under high current density conditions. However, the excess molecules are prone to causing local solvation structural disturbances and enhanced polarization at the interface, which is not conducive to long-term stable cycling.

[0016] Therefore, by limiting the concentration range of 1,4-butynediol, this invention ensures the interface control effect while avoiding the adverse effects introduced by excessive additives, thus achieving fine control of the interface behavior of the zinc anode. The concentration range is of great significance for achieving the technical effect of this invention.

[0017] Based on the above technical solution, the present invention may optionally introduce a low concentration of a second organic additive into the electrolyte system, the second organic additive comprising 1,3-propanediol.

[0018] The concentration of 1,3-propanediol is preferably 0.05 mM to 2 mM. Its function is to assist in regulating the stability of the solvation structure and hydrogen bond network at the electrode / electrolyte interface without interfering with the directional adsorption behavior of 1,4-butynediol, thereby alleviating local polarization and interface fluctuations under high current density conditions and further improving the operational stability of the electrolyte system.

[0019] It should be noted that 1,3-propanediol is not a necessary condition for achieving the technical effect of the present invention. Its introduction as a synergistic additive does not change the technical essence of the present invention, which uses 1,4-butynediol as the core interface-regulating molecule.

[0020] In a second aspect, the present invention also provides an aqueous zinc battery, comprising a zinc negative electrode, a positive electrode material, and an aqueous zinc battery electrolyte system as described above for high current density conditions. The aqueous zinc battery operates at a current density of not less than 10 mA·cm⁻¹. -2 Under the given current density conditions, zinc deposition / stripping reaction is carried out at the zinc negative electrode.

[0021] The aqueous zinc battery can be a symmetrical aqueous zinc battery or an asymmetrical aqueous zinc battery; wherein, the asymmetrical aqueous zinc battery may include, but is not limited to, Zn||Cu battery, Zn||MnO2 battery, Zn||V2O5 battery, etc.

[0022] The beneficial effects of the present invention are: (1) inhibiting dendrite growth: by precisely controlling the zinc anode interface with ultra-low concentration of 1,4-butynediol, the zinc deposition is homogenized under high current density conditions, which significantly inhibits dendrite growth.

[0023] (2) Improved interface stability: The 1,4-butynediol in the aqueous zinc battery electrolyte system of the present invention significantly reduces the hydrogen evolution and side reaction rates by weakening the water hydrogen bond network and reducing the activity of free water, thus maintaining interface stability.

[0024] (3) Achieving high current density and long life cycle: at 30 mA·cm -2 / 1 mAh·cm -2 Under certain conditions, the cycle life of Zn||Zn symmetric cells exceeds 4000 hours; at 10 mA·cm -2 Under certain conditions, the lifespan exceeds 6000 hours; the Zn||Cu battery operates at 1 mA·cm⁻¹. -2 It still maintains 99.5% coulomb efficiency after 3200 cycles.

[0025] (4) Improve full battery performance: at 1.0 A·g -1 At the specified current density, the capacity retention rate of the full cell (Zn||MnO2) reached 64.9% after 2500 cycles, demonstrating excellent reversibility and structural stability.

[0026] (5) Easy to operate and highly versatile: The electrolyte system is simple in composition and highly versatile. It is compatible with a variety of cathode materials and battery structures and has good prospects for engineering applications. Attached Figure Description

[0027] The battery systems shown in the following figures are all aqueous zinc batteries.

[0028] Figure 1 shows the Zn||Zn symmetric cell of the present invention at 10 mA·cm⁻¹. -2Cycle life curves at high current density; Figure 2 shows the cycle life curves of the Zn||Zn symmetric cell of the present invention at 30 mA·cm⁻¹. -2 Cycle life curves at high current density; Figure 3 shows the cycle life curves of the Zn||Zn symmetric cell of the present invention at 50 mA·cm⁻¹. -2 Figure 4 shows the cycle life curve at high current density; Figure 5 shows the coulombic efficiency curve of the Zn||Cu asymmetric cell of the present invention; Figure 6 shows the cycle stability curve of the Zn||MnO2 full cell of the present invention; Figure 7 shows the rate performance curve of the Zn||MnO2 full cell of the present invention; Figure 8 shows the scanning electron microscope comparison of zinc deposition morphology under electrolyte conditions containing and without 1,4-butynediol; Figure 9 shows the comparison of in-situ optical microscope observation results of the zinc deposition process; Figure 10 shows the cycle life curve of Comparative Example 4 of the present invention at 30 mA·cm⁻¹. -2 / 1mAh·cm -2 Cyclic curves under the specified conditions; Figure 11 shows the cyclic curves of Comparative Example 5 of the present invention at 10 mA·cm. -2 / 1mAh·cm -2 Cyclic curves under certain conditions. Detailed Implementation

[0029] The principles and features of this invention are described below. The examples given are for illustrative purposes only and are not intended to limit the scope of the invention. Where specific techniques or conditions are not specified in the embodiments, they should be performed according to the techniques or conditions described in the literature in this field, or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased through legitimate channels.

[0030] Materials and reagents source description: (1) Reagent source: All chemical reagents were used directly without further purification. Zinc sulfate heptahydrate (ZnSO4·7H2O, 99.5%) and 1,4-butynediol (BTDA, 98%) were purchased from Aladdin Reagent Co., Ltd. Manganese dioxide (MnO2, 99%), Super P carbon black, polyvinylidene fluoride (PVDF) binder and N-methyl-2-pyrrolidone (NMP) solvent were provided by KELUDE Experimental Equipment Technology Co., Ltd. Zinc foil (99.99%, 0.1 mm) was supplied by Shengyuan Metal Materials. Whatman GF / D glass fiber filter paper was used as the diaphragm, and all aqueous solutions were prepared with deionized water.

[0031] (2) Electrolyte: ① Preparation of the reference electrolyte (BE): Dissolve 8.26 g of zinc sulfate heptahydrate in 15 mL of deionized water to obtain a 2 M zinc sulfate solution. Stir the mixture magnetically at 500 rpm for 15 minutes to ensure complete dissolution.

[0032] It should be noted that the 2 M zinc sulfate solution is a high ionic strength electrolyte system commonly used in aqueous zinc batteries in this field. It can ensure high ionic conductivity while maintaining system stability, and is suitable for electrochemical testing under high current density conditions.

[0033] ② For the preparation method of electrolyte containing 1,4-butynediol (BTDA system): 6.46 mg of 1,4-butynediol was added to 15 mL of 2 M zinc sulfate electrolyte. After being magnetically stirred until completely dissolved, the solution was allowed to stand at room temperature for 12 hours to obtain an aqueous zinc battery electrolyte system with a concentration of 5 mM of 1,4-butynediol in the electrolyte.

[0034] (3) MnO2 cathode: MnO2 cathode was prepared by slurry casting process: 80 wt% MnO2, 10 wt% Super P and 10 wt% PVDF were mixed in NMP to form a uniform slurry, and then uniformly coated on hydrophobic carbon paper using an automatic coating machine; the coated electrode was vacuum dried at 80℃ for 8 hours and stamped into a 14 mm disc with an active material loading of 0.9~1.5 mg·cm³. -2 .

[0035] Example 1: Preparation of electrolyte containing 1,4-butynediol and preparation of electrolyte containing 1,4-butynediol (BTDA) for Zn||Zn symmetric cells: 8.26 g ZnSO4·7H2O was dissolved in 15 mL of deionized water to obtain a 2 M ZnSO4 solution. After stirring for 15 min, 6.46 mg of 1,4-butynediol was added, and stirring was continued until transparent and uniform. After standing for 12 h, an electrolyte with a concentration of 5 mM of 1,4-butynediol in the electrolyte was obtained.

[0036] Zn||Zn symmetric cell: A Zn||Zn symmetric cell was assembled in a CR2032 coin cell using two 14 mm diameter zinc foils as the working and counter electrodes, and GF / D glass fiber as the separator. The test current density was 10 mA·cm⁻¹. -2 30mA·cm -2 50 mA·cm -2 Surface capacity 1 mAh·cm -2 .

[0037] Example 2: A Zn||Cu asymmetric battery was prepared using the same method as in Example 1, with a 1,4-butynediol electrolyte. The working electrode was copper foil (14 mm in diameter), the counter electrode was zinc foil, and the separator was GF / D glass fiber. The electrolyte was prepared at 1 mA·cm⁻¹. -2 Current density, 0.5 mAh·cm -2 Cyclic charge-discharge tests were performed at the specified capacity.

[0038] Example 3: A 1,4-butynediol electrolyte was prepared for the MnO2||Zn full cell using the same method as in Example 1. MnO2, Super P, and PVDF were mixed at a mass ratio of 8:1:1, and NMP was added to form a slurry. This slurry was uniformly coated onto carbon paper, vacuum dried at 80°C for 8 h, and then die-cut into 14 mm diameter electrode sheets with an active material loading of approximately 1.0 mg·cm³. -2 .

[0039] A Zn||MnO2 full cell was assembled using Zn sheets as the negative electrode, GF / D glass fiber as the separator, and BE and 1,4-butynediol as the electrolyte. Rate performance and cycle life were tested within the voltage range of 0.9–1.9 V.

[0040] Example 4: Zn||Zn symmetric cells with 1,4-butynediol electrolyte under different zinc salt systems. This example illustrates the applicability of the electrolyte system described in this invention under different zinc salt conditions.

[0041] Zinc chlorate was used as the zinc salt. Zn(ClO4)2 was dissolved in deionized water to prepare a 1.0 M zinc chlorate aqueous solution. Then, 1,4-butynediol was added to the above solution to make its concentration in the electrolyte 5 mM. After magnetic stirring until completely dissolved, the solution was allowed to stand at room temperature for 12 h to obtain a zinc chlorate electrolyte containing 1,4-butynediol.

[0042] A Zn||Zn symmetric cell was assembled using two 14 mm diameter zinc foils as negative electrodes and a glass fiber membrane as the separator, along with the aforementioned electrolyte. The resulting cell was tested at 10 mA·cm⁻¹. -2 and 30 mA·cm -2 Constant current cycling tests were conducted under current density conditions, with an areal capacity of 1 mAh·cm². -2 .

[0043] Test results show that under the current density conditions, when using a zinc chlorate electrolyte system containing 1,4-butynediol, the Zn||Zn symmetric cell can maintain stable deposition / stripping behavior, with a stable voltage plateau and no obvious polarization abrupt changes or premature short circuits. This indicates that the low-concentration 1,4-butynediol addition strategy described in this invention is also applicable to different types of aqueous zinc salt electrolyte systems.

[0044] It should be noted that the concentration of Zn(ClO4)2 is not limited to 1.0 M as shown in the above examples. When selected in the range of 0.1 M to 5.0 M, stable zinc deposition / stripping behavior can also be achieved under the condition of introducing 1,4-butynediol as an interface control additive, without affecting the realization of the technical effect of the present invention.

[0045] Example 5: Aqueous Zinc Battery Electrolyte System with Low Concentration 1,3-Propanediol Synergistic Additive This example illustrates the effect of introducing a low concentration synergistic additive on the stability of the electrolyte system while maintaining 1,4-butynediol as the main interface regulating component.

[0046] A zinc sulfate electrolyte containing 1,4-butynediol was prepared using the same method as in Example 1, wherein the zinc sulfate concentration was 2 M and the 1,4-butynediol concentration in the electrolyte was 5 mM. Further, 1,3-propanediol was added to the electrolyte to achieve a concentration of 0.5 mM. After stirring thoroughly, the solution was allowed to stand at room temperature for 12 h to obtain an aqueous zinc battery electrolyte system containing composite organic additives.

[0047] Zn||Zn symmetric cells and Zn||Cu asymmetric cells were assembled using the above electrolyte, with zinc foil as the negative electrode, copper foil as the positive electrode, and a glass fiber membrane as the separator. The resulting cells were tested at 10 mA·cm⁻¹. -2 and 30 mA·cm -2 Cyclic testing was conducted under the given current density conditions.

[0048] Test results show that, without affecting the interfacial regulation effect of 1,4-butynediol, the introduction of low concentrations of 1,3-propanediol allows the battery to maintain stable cycling behavior under high current density conditions, further reducing voltage fluctuations and improving the repeatability and operational stability of the cycling process. This indicates that 1,3-propanediol, as a synergistic additive, can play an auxiliary regulatory role in the interfacial stability of the electrolyte system.

[0049] Comparative Example 1: Compared with Example 1, the electrolyte did not contain 1,4-butynediol, and the reference electrolyte (BE) was used. The rest was the same as in Example 1.

[0050] Comparative Example 2: Compared with Example 2, the electrolyte did not contain 1,4-butynediol, and the reference electrolyte (BE) was used. The rest was the same as in Example 2.

[0051] Comparative Example 3: Compared with Example 3, the electrolyte did not contain 1,4-butynediol, and the reference electrolyte (BE) was used. The rest was the same as in Example 3.

[0052] Comparative Example 4: Compared with Example 1, the amount of 1,4-butynediol added was increased to 0.086 g, and the rest was the same as in Example 1.

[0053] Comparative Example 5: Compared with Example 3, the amount of 1,4-butynediol added was increased to 0.086 g, and the rest was the same as in Example 3.

[0054] Experimental example: 1. Electrochemical measurement.

[0055] Electrochemical tests were conducted on the batteries prepared in Examples 1 to 3 and Comparative Examples 1 to 5 under laboratory conditions at room temperature. The symmetrical Zn||Zn battery (CR2032) was assembled using two zinc foils with a diameter of 14 mm and a thickness of 0.1 mm as electrodes, a glass fiber separator, and the prepared electrolyte. The Zn||MnO2 full cell was assembled similarly, using zinc foil as the negative electrode and carbon paper coated with manganese oxide as the positive electrode.

[0056] The symmetrical cell was subjected to constant current cycling on a Neware CT-4008Tn cell tester at a current density of 10 mA·cm⁻¹. -2 30 mA·cm -2 and 50 mA·cm -2 The area capacity is 1 mA·cm -2 At 1 mA·cm -2 Up to 30 mA·cm -2 Rate performance was evaluated within the current density range. Electrochemical impedance spectroscopy was measured in the frequency range of 100 kHz to 0.01 Hz with a 5 mV perturbation. Full cell performance was tested in the voltage range of 0.9 V–1.9 V. Rate performance was measured at 0.1 A·g -1 -10 A·g -1 Evaluation was conducted within the current density range, with long-term cycling at 1.0 A·g. -1 The tests were conducted at a current density of 2 mA·cm⁻¹. For in-situ optical microscopy, a custom-designed electrochemical cell was used, with the current density between the zinc working electrode and the counter electrode being 2 mA·cm⁻¹. -2 The morphology of the zinc coating was observed directly in real time over 120 minutes using the current density. The results are shown in Figures 1 to 11.

[0057] Figures 1 to 3 show the cycle life curves of the Zn||Zn symmetric cell at high current density; it can be seen that the Zn||Zn symmetric cell at 10 mA·cm -2 1 mAh·cm -2 Under cycling conditions, the BTDA system cycled for over 6000 h, and the voltage curve in the electrolyte containing 1,4-butynediol was stable with minimal fluctuations, while the blank electrolyte (BE) showed obvious voltage polarization and short-circuit signs. This indicates that 1,4-butynediol can effectively stabilize the Zn deposition / stripping process and significantly extend the cycle life. At higher current densities (30 mA·cm⁻¹), the BTDA system also showed stable voltage curves with minimal fluctuations. -2 The BE group failed at approximately 600 h, while the 1,4-butynediol group remained stable for over 4000 h (Figure 2). In contrast, the BE system exhibited significant polarization within 1000 h; this indicates that 1,4-butynediol has a more significant regulatory effect on interfacial stability and ion transport. At higher current densities (50 mA·cm⁻¹),-2 The 1,4-butynediol system maintained a stable voltage plateau (Figure 3). This indicates that 1,4-butynediol can effectively suppress dendrite growth and interfacial side reactions under extreme conditions. Meanwhile, SEM analysis showed that the deposited layer in the 1,4-butynediol electrolyte system was smooth and dense (Figure 8).

[0058] Figure 4 shows the coulombic efficiency (CE) curve of the Zn||Cu asymmetric cell; at 1 mA·cm -2 0.5 mAh·cm -2 Under cycling conditions, the initial coulombic efficiency of the 1,4-butynediol system is close to 100%, and the average coulombic efficiency (CE) of the 1,4-butynediol system is... ave The efficiency of zinc deposition reached 99.5%, and it operated stably for 3200 h with minimal fluctuations. The coulombic efficiency of the blank electrolyte (BE) decreased significantly after about 100 cycles, and the CE was significantly lower and unstable. This indicates that 1,4-butynediol can reduce side reactions (such as hydrogen evolution and dead zinc formation) and improve the reversible deposition efficiency of zinc.

[0059] Figure 5 shows the cycling stability curves of the Zn||MnO2 full cell; at 1.0 A·g -1 After 2500 cycles at the current density, the capacity retention rate reached 64.9%, while the BE system only maintained about 27.38%. The specific capacity retention rate in the 1,4-butynediol electrolyte was much higher than that in the BE group. This indicates that 1,4-butynediol not only improves the negative electrode interface, but also promotes the long-term cycling performance of the overall full cell.

[0060] Figure 6 shows a comparison of EIS impedance spectra at the electrode interface; the radius of the semicircle in the Nyquist plot of the 1,4-butynediol system is significantly smaller than that in the BE plot, indicating that 1,4-butynediol reduces the interfacial charge transfer impedance and enhances ion conduction and interfacial stability.

[0061] Figure 7 shows the rate performance curves of the Zn||MnO2 full cell; at 0.1 A·g -1 ~1.0 A·g -1 At different rates, the coulombic efficiency is close to 100%, and the 1,4-butynediol system has higher capacity and better recovery; indicating that the interface constructed by 1,4-butynediol can adapt to rapid ion migration and high-rate cycling.

[0062] Figure 8 shows a comparison of Zn deposition morphologies (SEM) with and without 1,4-butynediol electrolyte. It can be seen that the BE group has a rough, uneven surface with obvious dendrites; while the 1,4-butynediol group has a smooth, dense surface without obvious dendrite structure. This directly proves that 1,4-butynediol can induce uniform nucleation and growth of a dense Zn deposition layer.

[0063] Figure 9 shows the in-situ optical microscope comparison images; it can be seen that in the BE group, dendrites grew rapidly and penetrated the electrode after 60-120 min of deposition; while the 1,4-butynediol group had a smooth deposition process and uniform morphology. Further visualization verified the dendrite inhibition and interface stabilization effects of 1,4-butynediol.

[0064] Cyclic curves of different concentrations under the same test conditions in Comparative Example 4, 10 mM 1,4-butynediol 30 mA·cm -2 / 1 mAh·cm -2 Short circuit after approximately 1900 h of cycling (Figure 10); Cycling curves of Comparative Example 5 under the same test conditions with different concentrations, 10 mM 1,4-butynediol 10 mA·cm⁻¹ -2 / 1mAh·cm -2 Short circuits occurred after approximately 2800 hours of cycling (Figure 11). During long-term cycling, the zinc anode deposition / stripping gradually accumulated morphological inhomogeneities, leading to localized interface instability and ultimately a significant decrease in cycling stability. Under high current density conditions, concentration polarization and enhanced local electric field further exacerbated the inhomogeneous deposition, making short circuits more likely to occur.

[0065] Further analysis revealed that under high current density conditions, when the electrolyte lacks effective interface control components or the additive concentration is too high, the zinc anode is prone to uneven nucleation and local electric field concentration during repeated deposition / stripping. This leads to dendrites rapidly extending along the local preferential growth direction and eventually piercing the separator, thereby causing internal short-circuit failure. The 1,4-butynediol described in this invention effectively delays the occurrence of the above-mentioned failure process by inducing uniform nucleation and ordered growth.

[0066] In summary, the present invention provides an electrolyte containing 1,4-butynediol; the hydroxyl group (-OH) and alkyne bond (-C≡C-) in the 1,4-butynediol molecule can work together on the hydrogen bond network of water molecules and the surface of metallic zinc to regulate the crystal orientation and interfacial reaction kinetics of zinc deposition, thereby inhibiting the disordered growth of zinc dendrites and obtaining a uniform and dense deposition layer.

[0067] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. An aqueous zinc battery electrolyte system for use under high current density conditions, characterized in that, The aqueous zinc battery electrolyte system includes: zinc salt and a first organic additive; the first organic additive includes 1,4-butynediol.

2. The aqueous zinc battery electrolyte system for high current density conditions according to claim 1, characterized in that, The molar ratio of 1,4-butynediol to the zinc salt is 1 × 10⁻⁶. -4 ~5×10 -2 ∶1.

3. The aqueous zinc battery electrolyte system for high current density conditions according to claim 2, characterized in that, The molar ratio of 1,4-butynediol to the zinc salt is 2 × 10⁻⁶. -3 ~1×10 -2 ∶1.

4. The aqueous zinc battery electrolyte system for high current density conditions according to claim 1, characterized in that, The zinc salt includes at least one of ZnSO4 and Zn(ClO4)2.

5. The aqueous zinc battery electrolyte system for high current density conditions according to claim 4, characterized in that, When the zinc salt is ZnSO4, the concentration of ZnSO4 in the aqueous zinc battery electrolyte system is 0.1 M to 5.0 M.

6. A water-based zinc battery electrolyte system for high current density conditions according to any one of claims 1 to 5, characterized in that, The aqueous zinc battery electrolyte system also includes an aqueous solvent.

7. An aqueous zinc battery electrolyte system for high current density conditions according to any one of claims 1 to 5, characterized in that, The concentration of 1,4-butynediol in the aqueous zinc battery electrolyte system is 1 mM to 20 mM.

8. The aqueous zinc battery electrolyte system for high current density conditions according to claim 7, characterized in that, The concentration of 1,4-butynediol in the aqueous zinc battery electrolyte system is 2 mM to 8 mM.

9. An aqueous zinc battery electrolyte system for high current density conditions according to any one of claims 1 to 5, characterized in that, The aqueous zinc battery electrolyte system further includes a second organic additive; the second organic additive includes 1,3-propanediol, the concentration of 1,3-propanediol in the aqueous zinc battery electrolyte system is 0.05 mM to 2 mM, and the molar ratio of 1,3-propanediol to 1,4-butynediol is 0.01 to 0.3:

1.

10. An aqueous zinc battery, characterized in that, It includes a zinc negative electrode, a positive electrode, and an aqueous zinc battery electrolyte system for high current density conditions as described in any one of claims 1 to 9.

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