A design of negative solid-state electrolyte interface based on aqueous zinc-ion battery

Abstract

The application belongs to the technical field of aqueous zinc ion batteries, and particularly relates to a preparation method for constructing a solid-state electrolyte interface layer on the surface of a zinc metal negative electrode and application thereof. In order to alleviate the problems of dendrite growth, hydrogen evolution reaction and the like occurring in the cycle process of the battery, the coating is introduced, which can effectively avoid the direct contact of the zinc metal negative electrode with the electrolyte, can inhibit the occurrence of the side reaction to a certain extent, can reduce the risk of battery failure caused by the problems such as the penetration of dendrites through the diaphragm in the charge-discharge process of the zinc negative electrode, and can further improve the cycle stability of the battery and prolong the service life of the battery.

Description

Technical Field

[0001] This invention belongs to the field of aqueous zinc-ion battery technology, and in particular relates to a method for preparing a solid electrolyte interface (SEI) layer on the surface of a zinc metal negative electrode and its application in aqueous zinc-ion batteries. Background Technology

[0002] Energy is one of the major challenges facing the world. With population growth, economic development, and changing lifestyles, energy shortages are becoming increasingly prominent. Traditional fossil fuel resources are finite and non-renewable, and over-exploitation leads to environmental pollution and climate change. Therefore, it is necessary to accelerate the development and promotion of renewable and clean energy sources, such as solar, wind, and hydropower, to reduce dependence on traditional energy sources and lower carbon emissions. However, clean energy is characterized by fluctuations and intermittency, making it difficult to ensure a stable energy supply. Therefore, developing efficient energy storage devices has become an effective way to solve energy and environmental problems. Secondary batteries, as important energy storage devices that convert chemical energy into electrical energy, play a crucial role in comprehensively alleviating the energy crisis and environmental problems. Currently, lithium-ion batteries, with their high energy density and long cycle life, are widely used in new energy vehicles and digital products, but they also have some limitations. These include the high price of lithium, significant safety risks, and the potential for thermal runaway and internal short circuits. Compared to lithium-ion batteries, aqueous zinc-ion batteries use an aqueous solution as the electrolyte, giving them flame-retardant properties and effectively reducing the risk of spontaneous combustion and explosion. Furthermore, zinc metal resources are relatively abundant, with reserves approximately 300 times higher than those of lithium-ion batteries, reducing the manufacturing cost of aqueous zinc-ion batteries. Additionally, aqueous zinc-ion batteries possess a high theoretical capacity (approximately 820 mAh g⁻¹). -1 This allows for the storage of more electrical energy per unit mass or volume.

[0003] Side reactions at the negative electrode are a bottleneck restricting the development of aqueous zinc-ion batteries. During charge-discharge cycles, the local current density increases in the sharp regions of the electrode surface, forming a high-intensity non-uniform electric field. This sharp-point effect leads to dendrite formation. Dendrite growth increases the surface area of ​​the negative electrode, providing more reaction sites and further promoting side reactions. Simultaneously, the hydrogen gas produced by these side reactions makes the negative electrode surface loose and porous, leading to uneven zinc ion deposition, increasing the surface roughness of the zinc negative electrode and exacerbating electrode polarization. This series of problems directly or indirectly causes inefficient zinc ion deposition / dissolution, resulting in a very short cycle life.

[0004] Current solutions mainly include: surface modification of the negative electrode interface; adding specific additives to the electrolyte to improve the chemical environment of the electrolyte; and modifying the separator to improve the ion transport rate. In recent years, researchers have promoted the orderly deposition of zinc ions by constructing different solid electrolyte interface layers. Studies have shown that metal oxides such as CaCO3 and Fe2O3 can be used as negative electrode protective coating materials. In 2022, Naresh N et al. studied the construction of aqueous zinc-ion battery negative electrodes using mesoporous zincophilic TiO2 nanoparticles. Naresh N, Eom S, Jeong SH, et al. Dendrite-free Zn anodes enabled by a hierarchical zincophilic TiO2 layer for rechargeable aqueous zinc-ion batteries[J]. Applied Surface Science, 2022, 606: 154932. At a current density of 0.25 mA cm⁻¹ -2 At that time, the capacity was 0.05 mAh cm⁻¹. -2 Symmetric cells can cycle stably for 900 hours. However, the scraping method suffers from poor adhesion and tensile strength between the two interfaces, which may lead to coating cracks and detachment from the electrode. Therefore, how to construct a stable zinc anode, suppress side reactions, and improve the cycle stability of aqueous zinc-ion batteries has become a critical issue that urgently needs to be addressed. Summary of the Invention

[0005] In view of the above-mentioned deficiencies of the prior art, the technical problem to be solved by the present invention is to provide a negative electrode material that can uniformly deposit / dissolve zinc ions during cycling, suppress side reactions such as dendrite growth, and thus improve its cycle stability in aqueous zinc-ion batteries.

[0006] To achieve the above objectives, the present invention provides a method for preparing a zinc-copper dihydroxy salt anode material, comprising the following steps:

[0007] S1: First, the zinc sheet that has been pretreated with hydrochloric acid is dried and then placed in a muffle furnace for pre-oxidation at a specific temperature to obtain a zinc sheet with zinc oxide on its surface.

[0008] S2: The calcined zinc sheet is immersed in a mixed solution containing N,N-dimethylformamide and copper salt. After thorough contact, it is removed and dried. This yields an aqueous zinc-ion battery negative electrode with zinc-copper dihydroxy salt on its surface.

[0009] In a preferred embodiment, in S1, the concentration of the hydrochloric acid solution is one of 0.1~2 mol / L.

[0010] In a preferred embodiment, in S1, the acid treatment process is carried out in an ultrasonic machine for 10-15 minutes at an ultrasonic temperature of 20-25°C.

[0011] In a preferred embodiment, in S1, the calcination temperature is 300°C, and the heating program is as follows: the heating rate is 1~5°C / min, and the temperature is raised to 300°C and held for 10~24 hours.

[0012] In a preferred embodiment, in S2, N,N-dimethylformamide solution is mixed with deionized water to form solution A, copper salt is dissolved in deionized water to form solution B, calcined zinc sheet is first placed in solution A, and after the solution temperature is raised to 30~34°C, solution B is added to solution A.

[0013] In a preferred embodiment, in S2, the volume ratio of N,N-dimethylformamide solution to deionized water is 1:1 to 3:1.

[0014] In a preferred embodiment, in S2, the copper salt used is copper nitrate trihydrate with a concentration of 0.5~1 mol / L.

[0015] In a preferred embodiment, in S2, the zinc sheet is soaked for 1 minute.

[0016] In a second aspect, the present invention provides the application of the zinc-copper dihydroxy salt anode material in an aqueous zinc-ion battery.

[0017] In a preferred embodiment, in an aqueous zinc-ion battery, the zinc-copper dihydroxy salt negative electrode operates at a current density of 2 mA cm⁻¹. -2 The capacity is 1 mAh cm -2 At that time, the symmetrical battery can cycle stably for 1000 hours.

[0018] Technical effect

[0019] This invention provides a simple, low-cost, and rapid method for fabricating a solid electrolyte interface layer. Specifically, it employs an in-situ growth synthesis method to construct a robust zinc-copper dihydroxyl solid electrolyte interface layer on the surface of a zinc sheet. Compared to pure zinc, the zinc-loving properties of the designed solid electrolyte interface layer provide more nucleation sites for zinc ions during deposition, accelerating the charge transfer kinetics of zinc ions and achieving stable three-dimensional diffusion. This significantly suppresses dendrite growth. Furthermore, the strong hydrogen bonding effect between the hydroxyl groups and water molecules in the solid electrolyte interface layer reduces the activity of free water, weakening the solvation in the zinc ion outer Helmholtz layer and diffusion layer on the electrode surface.

[0020] This invention controls the thickness of the protective layer during the reaction process by soaking time. By controlling the soaking time to 0.5-2 h, zinc-copper double-hydroxyl anode materials with different morphologies and thicknesses are prepared. The protective layer with excellent thermal / chemical stability acts as a strong physical barrier, greatly improving corrosion resistance and hindering the direct interaction between zinc anode and water, thereby achieving a stable zinc metal anode.

[0021] This invention achieves a solid electrolyte interface layer of suitable thickness by optimizing the preparation process, primarily by controlling the electrochemical reaction at the electrode-electrolyte interface, thereby stabilizing the negative electrode of an aqueous zinc-ion battery. The current density is 2 mA / cm². -2 At that time, the capacity was 1 mAh cm -2 At that time, the symmetrical battery can cycle stably for 1000 hours. Attached Figure Description

[0022] Figure 1 This is a scanning electron microscope (SEM) image of the zinc-copper dihydroxy salt solid electrolyte interface layer prepared in Example 1 of this invention;

[0023] Figure 2 This is a scanning electron microscope image of the zinc-copper dihydroxy salt solid electrolyte interface layer prepared in Example 2 of the present invention;

[0024] Figure 3 This is a scanning electron microscope image of the zinc-copper dihydroxy salt solid electrolyte interface layer prepared in Example 3 of the present invention;

[0025] Figure 4 This is a scanning electron microscope image of the zinc-copper dihydroxy salt solid electrolyte interface layer prepared in Example 4 of the present invention;

[0026] Figure 5 This is a scanning electron microscope image of the zinc-copper dihydroxy salt solid electrolyte interface layer prepared in Example 5 of the present invention;

[0027] Figure 6 These are the Tafel curves of Comparative Example 1 and Examples 1-5 of the present invention;

[0028] Figure 7 This is a schematic diagram illustrating the state control of the electrochemical reaction at the electrode-electrolyte interface according to the present invention. Detailed Implementation

[0029] The following description, with reference to the accompanying drawings, illustrates several preferred embodiments of the present invention to make its technical content clearer and easier to understand. The present invention can be embodied in many different forms, and the scope of protection of the present invention is not limited to the embodiments mentioned herein.

[0030] Example 1

[0031] In-situ growth method for preparing zinc-copper dihydroxy salt anode materials:

[0032] First, zinc sheets with a diameter of 10-18 mm are pretreated in an ultrasonic machine with 1 mol / L hydrochloric acid solution for 10-15 min. After drying, the zinc sheets are placed in a muffle furnace and heated from room temperature to 300℃ at a rate of 3℃ / min, and then kept at that temperature for 12 hours.

[0033] The calcined zinc sheet was placed in a mixture of 8 mL N,N-dimethylformamide solution and 8 mL deionized water, and then transferred to a heated stirring table (30℃~34℃). A solution of 1.74 g copper nitrate trihydrate dissolved in 10 mL deionized water was added to the mixture. After soaking for 1 min, the solution was washed with deionized water and dried to obtain the target product.

[0034] The prepared samples were assembled into symmetrical cells with 2 M ZnSO4 as the electrolyte and glass fiber as the separator.

[0035] Scanning electron microscope images of the prepared zinc-copper dihydroxy salt anode material are as follows: Figure 1 As shown.

[0036] Example 2

[0037] In-situ growth method for preparing zinc-copper dihydroxy salt anode materials:

[0038] First, zinc sheets with a diameter of 10-18 mm are pretreated in an ultrasonic machine with 1 mol / L hydrochloric acid solution for 10-15 min. After drying, the zinc sheets are placed in a muffle furnace and heated from room temperature to 300℃ at a rate of 3℃ / min, and then kept at that temperature for 12 hours.

[0039] The calcined zinc sheet was placed in a mixture of 8 mL N,N-dimethylformamide solution and 8 mL deionized water, and then transferred to a heated stirring table (30℃~34℃). A solution of 1.74 g copper nitrate trihydrate dissolved in 10 mL deionized water was added to the mixture. After soaking for 5 min, the solution was washed with deionized water and dried to obtain the target product.

[0040] The prepared samples were assembled into symmetrical cells with 2 M ZnSO4 as the electrolyte and glass fiber as the separator.

[0041] Scanning electron microscope images of the prepared zinc-copper dihydroxy salt anode material are as follows: Figure 2 As shown.

[0042] Example 3

[0043] In-situ growth method for preparing zinc-copper dihydroxy salt anode materials:

[0044] First, zinc sheets with a diameter of 10-18 mm are pretreated in an ultrasonic machine with 1 mol / L hydrochloric acid solution for 10-15 min. After drying, the zinc sheets are placed in a muffle furnace and heated from room temperature to 300℃ at a rate of 3℃ / min, and then kept at that temperature for 12 hours.

[0045] The calcined zinc sheet was placed in a mixture of 16 mL N,N-dimethylformamide solution and 8 mL deionized water, and then transferred to a heated stirring table (30℃~34℃). A solution of 1.74 g copper nitrate trihydrate dissolved in 10 mL deionized water was added to the mixture. After soaking for 10 min, the sample was washed with deionized water and dried to obtain the target product.

[0046] The prepared samples were assembled into symmetrical cells with 2 M ZnSO4 as the electrolyte and glass fiber as the separator.

[0047] Scanning electron microscope images of the prepared zinc-copper dihydroxy salt anode material are as follows: Figure 3 As shown.

[0048] Example 4

[0049] In-situ growth method for preparing zinc-copper dihydroxy salt anode materials:

[0050] First, zinc sheets with a diameter of 10-18 mm are pretreated in an ultrasonic machine with 1 mol / L hydrochloric acid solution for 10-15 min. After drying, the zinc sheets are placed in a muffle furnace and heated from room temperature to 300℃ at a rate of 3℃ / min, and then kept at that temperature for 12 hours.

[0051] The calcined zinc sheet was placed in a mixture of 24 mL N,N-dimethylformamide solution and 8 mL deionized water, and then transferred to a heated stirring table (30℃~34℃). A solution of 1.74 g copper nitrate trihydrate dissolved in 10 mL deionized water was added to the mixture. After soaking for 30 min, the solution was washed with deionized water and dried to obtain the target product.

[0052] The prepared samples were assembled into symmetrical cells with 2 M ZnSO4 as the electrolyte and glass fiber as the separator.

[0053] Scanning electron microscope images of the prepared zinc-copper dihydroxy salt anode material are as follows: Figure 4 As shown.

[0054] Example 5

[0055] In-situ growth method for preparing zinc-copper dihydroxy salt anode materials:

[0056] First, zinc sheets with a diameter of 10-18 mm are pretreated in an ultrasonic machine with 1 mol / L hydrochloric acid solution for 10-15 min. After drying, the zinc sheets are placed in a muffle furnace and heated from room temperature to 300℃ at a rate of 3℃ / min, and then kept at that temperature for 12 hours.

[0057] The calcined zinc sheet was placed in a mixture of 24 mL N,N-dimethylformamide solution and 8 mL deionized water, and then transferred to a heated stirring table (30℃~34℃). A solution of 1.74 g copper nitrate trihydrate dissolved in 10 mL deionized water was added to the mixture. After soaking for 60 min, the solution was washed with deionized water and dried to obtain the target product.

[0058] The prepared samples were assembled into symmetrical cells with 2 M ZnSO4 as the electrolyte and glass fiber as the separator.

[0059] Scanning electron microscope images of the prepared zinc-copper dihydroxy salt anode material are as follows: Figure 5 As shown.

[0060] Comparative Example 1

[0061] First, zinc sheets with a diameter of 10-18 mm are pretreated in an ultrasonic machine with 1 mol / L hydrochloric acid solution for 10-15 min. After drying, the zinc sheets are placed in a muffle furnace and heated from room temperature to 300℃ at a rate of 3℃ / min, and then kept at that temperature for 12 hours.

[0062] The pre-oxidized zinc sheet and the zinc sheet with zinc-copper dihydroxyl salt modified surface obtained in Examples 1-5 were subjected to Tafel testing under a three-electrode system. Figure 6 , Figure 7 As shown.

[0063] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A method for preparing a solid electrolyte interface layer on the surface of a zinc metal anode, the method comprising: S1: First, the zinc sheet that has been pretreated with hydrochloric acid is dried and then placed in a muffle furnace for pre-oxidation calcination at 200~400℃ to obtain a zinc sheet with zinc oxide on its surface. S2: Immerse the calcined zinc sheet in a mixed solution containing N,N-dimethylformamide and copper salt. After thorough contact, the sample is removed and dried to obtain an aqueous zinc-ion battery negative electrode containing zinc-copper dihydroxy salt on its surface. Solution A is formed by uniformly mixing N,N-dimethylformamide solution and deionized water, while solution B is formed by dissolving copper salt in deionized water. The calcined zinc sheet is first placed in solution A. After the solution temperature is raised to 30~34℃, solution B is added to solution A. The volume ratio of N,N-dimethylformamide solution to deionized water is 1:1~3:

1. The copper salt used is copper nitrate trihydrate with a concentration of 0.5~1mol / L, and the zinc sheet is soaked for 0.5~2 h.

2. The preparation method according to claim 1, wherein, In S1, the concentration of the hydrochloric acid solution is 0.1~2 mol / L.

3. The preparation method according to claim 1, wherein, In S1, the hydrochloric acid pretreatment process is carried out in an ultrasonic machine for 10-15 minutes at an ultrasonic temperature of 20-25°C.

4. The preparation method according to claim 1, wherein, In S1, the calcination temperature is 300℃, and the heating program is as follows: the heating rate is 1~5℃ / min, and the temperature is raised to 300℃ and held for 10~24 h.

5. The aqueous zinc-ion battery anode material containing zinc-copper dihydroxy salt on its surface is obtained by the preparation method according to any one of claims 1-4, wherein the diameter of the zinc sheet is 10-18 mm.

6. The application of the aqueous zinc-ion battery negative electrode material containing zinc-copper dihydroxy salt on its surface as described in claim 5 in an aqueous zinc-ion battery, at a current density of 2 mA cm⁻¹ -2 The capacity is 1 mAh cm -2 At that time, the symmetrical battery could be stably cycled for 1000 hours.

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