Application of in-situ constructed nanoparticle layer in zinc negative electrode protection layer

Abstract

According to the invention, a stable Zn negative electrode is realized by forming an in-situ constructed zinc-loving and hydrophobic interface through simple soaking, and a unique carbonyl functional interface layer is formed in situ by soaking zinc foil in a glyoxal solution. On the basis of strong electronegativity of carbonyl, obvious interaction can be generated on zinc ions. And moreover, the hydrophobicity of the Zn negative electrode is improved by the unique particle morphology formed in situ. Through reconstruction of a negative electrode interface by glyoxal, a contact angle result shows that the unique morphology of glyoxal formed on the surface of the Zn negative electrode can increase the hydrophobicity of the Zn negative electrode. Therefore, a compact granular unique morphology is formed in situ on the surface of the Zn negative electrode through simple soaking, so that the Zn negative electrode becomes hydrophobic, and side reactions such as hydrogen evolution and by-products at an electrolyte / electrode interface are slowed down. As a result, symmetric cells exhibit more than 3200 hours at 1 mA cm <-2 > and 1 mAh cm <-2 >. Various types of positive electrodes can be matched, and excellent cycling stability is realized; for example, when matched with a MnVO positive electrode, it can be stably cycled for 2000 times.

Description

Technical Field

[0001] The present invention relates to the field of electrochemical energy storage, and in particular to the preparation of a zinc negative electrode interface coating for an aqueous zinc ion battery and the application of the battery. Background Art

[0002] The emergence and development of aqueous zinc-ion batteries (AZIBs) provide opportunities for green energy storage systems and large-scale applications with their high safety, high stability and low cost, thereby reversing the dilemma of energy crisis and environmental pollution. Due to its unique advantages, including high theoretical capacity (820 mA h g −1 Zinc metal is considered the most common anode in aqueous batteries due to its low redox potential (-0.76 V vs. SHE), abundant global reserves, compatibility with aqueous electrolytes, fundamental safety issues, and environmental friendliness. However, zinc metal anodes face interfacial issues such as dendrite growth, hydrogen evolution reaction (HER), and corrosion in practical applications, severely limiting the battery's cycle life and commercialization.

[0003] In response to the above problems, researchers have developed a variety of interface engineering strategies, which are mainly divided into two types of methods: non-in situ construction and in situ construction. Among them, the non-in situ coating and the zinc substrate are mainly bonded through physical adsorption or weak chemical bonds, lacking strong interface interactions, and it is difficult to completely penetrate and cover the microscopic bumps and scratches on the surface of the zinc foil. These unprotected areas will become the starting points for dendrite growth and side reactions. In contrast, the in situ construction method directly forms a protective layer on the surface of zinc metal through chemical reactions. This method can overcome many shortcomings of non-in situ coatings and show unique advantages. The in situ method can cleverly design the coating composition, achieve precise control of nano-scale or submicron-scale ultra-thin coatings, and realize multiple functions at the same time. It is easy to operate, reacts quickly, and is suitable for large-scale production. Therefore, making full use of the in situ construction function to change the Zn 2+ The deposition pattern at the interface is the key to achieving stable operation of surface coating-modified Zn anode.

[0004] This in situ constructed Gly@Zn anode exhibits a "hydrophobic-zincophilic" interaction, providing zinc-philic nucleation sites while also blocking water molecules from contact, making it a promising coating for zinc anodes. A key challenge with commercial zinc foil is the uncontrolled interfacial heterogeneous deposition that leads to a large accumulation of zinc ions around the needle tip, resulting in low zinc utilization and continuous side reactions and hydrogen evolution. Therefore, this Gly@Zn anode avoids these drawbacks by selecting glyoxal, which contains zinc-philic and electronegative carbonyl groups as nucleophilic groups, to form a unique carbonyl-functionalized interfacial layer in situ. Modulating the structure of the Gly@Zn anode to mitigate side reactions such as hydrogen evolution and byproducts at the electrolyte / electrode interface is crucial. However, simultaneously imparting low polarization to the surface coating is challenging. However, this method is simple to operate, has a rapid reaction, and significantly reduces production costs and energy consumption, which is rarely reported. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for forming an in-situ zinc-philic hydrophobic interface by simple immersion to achieve the application of a stable Zn negative electrode in AZMBs, thereby inducing Zn 2+ Uniform deposition blocks water molecules from contact. The coating prevents cracking and flaking during cycling. This addresses the uneven coating and excessive thickness that can occur with conventional AZMBs anodes during cycling. This improves the cycling stability of the full cell, thereby enhancing the practical application of zinc metal batteries.

[0006] To achieve the above objectives, the present invention adopts the following technical solutions: The zincophilic hydrophobic interface is mainly constructed for the Gly@Zn anode, which is formed by the zinc anode and glyoxal solution.

[0007] Based on the above solution, the zinc negative electrode is zinc foil.

[0008] Based on the above scheme, the control group was untreated zinc foil.

[0009] Based on the above scheme, the Gly@Zn negative electrode is a zinc foil that has been immersed in glyoxal at room temperature for 3 h.

[0010] The concentration of the electrolyte salt is 2M, where M is the volume concentration, that is, the number of moles of electrolyte salt. The ratio of the volume of the solvent to the volume of the solvent is M: mol L -1 .

[0011] Based on the above scheme, preferably, the zinc salt is zinc sulfate solution.

[0012] Based on the above scheme, the zinc metal battery includes a positive electrode, a separator, an electrolyte and a zinc negative electrode; the positive electrode material is a manganese-based material and a vanadium-based material; the manganese-based material is one or two of MnO2 and α-MnO2; the vanadium-based material is V2O5, VO2, MnVO and NH4V5O10 One or more of; the membrane is a glass fiber membrane or a Celgard membrane.

[0013] The present invention also provides the application of in-situ constructed zinc-philic hydrophobic interface coating in aqueous zinc metal batteries.

[0014] Innovation Develop a functional coating with a site-specific zinc-philic hydrophobic interface to achieve a stable Zn anode, which will promote the Zn 2+ Uniform deposition. Glyoxal adsorption on the surface increases the zinc affinity of the Gly@Zn anode and reduces the nucleation barrier for zinc ions. Glyoxal restructures the anode interface, forming a unique morphology that increases hydrophobicity. Consequently, it enhances the desolvation of Zn ions by Gly@Zn and the interfacial dynamics. The uniform in situ coating also prevents cracking and delamination during cycling.

[0015] Beneficial effects of the present invention: An innovative in-situ constructed zinc-philic hydrophobic interface functional coating is used to achieve a stable Zn anode, which changes the formation mode and promotes the Zn 2+ The uniform deposition, good zinc affinity and hydrophobicity, avoid cracking and peeling of the coating during cycling. The zinc plating potential of the Gly@Zn negative electrode (46 mV) is lower than that of bare Zn (57 mV), which indicates that the Gly@Zn coating reduces the Zn deposition barrier and enhances the Zn deposition kinetics. Therefore, the Gly@Zn||Gly@Zn symmetric battery has a low voltage polarization and can be used at 1 mA cm -2 and 1 mAh cm -2 Stable cycling for more than 3200 hours at 5 mA cm -2 and 1 mAh cm -2 The Zn||MnVO coin cell paired with a MnVO cathode was stably cycled for over 3850 hours at a current density of 5 A / g. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 : SEM morphology of Gly@Zn and bare zinc in Example 1.

[0017] Figure 2 : A Zn coating image was prepared in Example 2.

[0018] Figure 3 : Zinc-copper CV curves of Gly@Zn and bare zinc tests in Example 3.

[0019] Figure 4 : Nucleation overpotential curves of Gly@Zn and bare zinc tests in Example 4.

[0020] Figure 5 : LSV curves of Gly@Zn and bare zinc tests in Example 5.

[0021] Figure 6 : XRD pattern of the negative electrode after cycling in Example 6.

[0022] Figure 7 : Cross-sectional SEM image of the negative electrode Gly@Zn in Example 7 and its element distribution map.

[0023] Figure 8 :Gly@Zn||Gly@Zn symmetric cell in Example 8 at room temperature 1 mA cm -2 and 1 mAh cm -2 Lower cycle stability diagram.

[0024] Figure 9 : Gly@Zn||Gly@Zn symmetric cell in Example 9 at room temperature 5 mA cm -2 and 1 mAh cm -2 Lower cycle stability diagram.

[0025] Figure 10 : Cycling stability diagram of the Zn||MnVO button cell in Example 10.

[0026] Figure 11 : Practical application of the Zn||MnVO soft-pack battery in Example 11. DETAILED DESCRIPTION

[0027] The following examples are provided to further illustrate the present invention, but are not intended to limit the scope of the present invention.

[0028] Example 1:

[0029] First, a 2M ZnSO₄ electrolyte was prepared in a 50 mL volumetric flask using 28.756 g of ZnSO₄.7H₂O and deionized water. Zinc foil was immersed in a 40% aqueous solution of glyoxal at room temperature for 2, 3, and 4 hours, respectively. The foil was then rinsed with deionized water and air-dried. Electrode pieces with a diameter of 12 mm were then cut. The resulting Gly@Zn anode and bare zinc were then examined using SEM.

[0030] Test results see Figure 1 The SEM images shown reveal a striking feature of the Gly@Zn anode morphology, where the surface of the Zn anode adsorbed with glyoxal is covered with dense square particles, while the bare Zn surface has pits.

[0031] Example 2:

[0032] An in situ zinc-philic and hydrophobic interfacial coating was prepared for the zinc metal anode by immersion.

[0033] Test results see Figure 2 .

[0034] Example 3:

[0035] Electrochemical tests were performed on the Gly@Zn negative electrode prepared in Example 2.

[0036] Test results see Figure 3 The zinc-copper CV curves of Gly@Zn and bare zinc tests indicate that the Gly@Zn anode reduces the Zn deposition barrier and enhances the Zn deposition kinetics.

[0037] Example 4:

[0038] Electrochemical tests were performed on the Gly@Zn negative electrode prepared in Example 2.

[0039] Test results see Figure 4 The nucleation overpotential curves of Gly@Zn and bare Zn tests show that the deposition overpotential of Gly@Zn anode is lower than that of bare Zn anode.

[0040] Example 5:

[0041] Electrochemical tests were performed on the Gly@Zn negative electrode prepared in Example 2.

[0042] Test results see Figure 5 The LSV curves of Gly@Zn and bare zinc tests show that the low HER potential of the Gly@Zn negative electrode has the effect of inhibiting hydrogen evolution and corrosion side reactions.

[0043] Example 6:

[0044] The Gly@Zn negative electrode prepared in Example 2 was tested using a button cell. A Gly@Zn||Gly@Zn symmetrical cell was assembled and tested at 1 mA cm -2 and 1 mAh cm -2 Constant current charge and discharge test was carried out under the conditions of .

[0045] After 30 cycles of deposition, the zinc negative electrode was washed with deionized water, dried, and the surface of the zinc foil was analyzed by XRD. Figure 6 , a large amount of Zn4SO4(OH)6·xH2O hydrogen evolution byproduct appeared on the bare zinc surface. However, almost no byproduct appeared on the Gly@Zn surface. These results indicate that hydrogen evolution corrosion on Gly@Zn is greatly suppressed.

[0046] Example 7:

[0047] The Gly@Zn negative electrode prepared in Example 2 was analyzed by SEM on the cross section of the Gly@Zn.

[0048] Test results see Figure 7 This indicates that there is no delamination between the Gly@Zn coating and the zinc foil. The corresponding element distribution shows that the Zn element is uniformly distributed in the Gly@Zn coating.

[0049] Example 8:

[0050] The Gly@Zn anode prepared in Example 2 was used to assemble the Gly@Zn||Gly@Zn symmetric battery at 1 mA cm -2 , 1 mAhcm -2 Long cycle stability test was carried out under

[0051] Test results see Figure 8 The Gly@Zn negative electrode has the best cycle performance, which shows that the Gly@Zn negative electrode significantly improves the cycle performance of the battery due to its suppression of zinc dendrites and hydrogen evolution reaction.

[0052] Example 9:

[0053] The Gly@Zn anode prepared in Example 2 was used to assemble the Gly@Zn||Gly@Zn symmetric battery at 5 mA cm -2 , 1 mAhcm -2 Long cycle stability test was carried out under

[0054] Test results see Figure 9 Compared with bare zinc, the Gly@Zn negative electrode has a longer stable cycle time, which shows that thanks to the suppression of zinc dendrites and hydrogen evolution reaction by the Gly@Zn negative electrode, reversible zinc deposition and dissolution can be achieved at room temperature.

[0055] Example 10: The Gly@Zn anode prepared in Example 2 was used to assemble a Gly@Zn||MnVO full cell.

[0056] Synthesis of MnVO: 0.37 g of V2O5 and 2 mL of H2O2 were dissolved in 50 mL of distilled water. 0.17 g of MnSO4⋅H2O was dissolved in 30 mL of distilled water. Both solutions were then transferred to a 100 mL polytetrafluoroethylene container, placed in a stainless steel reactor, heated to 120°C, and maintained at 120°C for 10 hours. After drying in a vacuum oven at 80°C for 12 hours, the color turned green, resulting in the MnVO cathode powder. The cathode slurry consisted of 70% of the prepared active material, 20% of the conductive agent, and 10% of the polymer binder. The slurry was then coated on stainless steel foil to prepare the cathode and dried under vacuum at 80°C for 12 hours.

[0057] Battery assembly: 2M zinc sulfate electrolyte was used to assemble Gly@Zn||MnVO full battery at 5 A g-1 The test conditions are to carry out charge and discharge tests at room temperature.

[0058] Test results see Figure 10 Gly@Zn||MnVO full cell at 5 A g -1 It exhibits a remarkable capacity retention of 84.6% after 2000 cycles at a high current density.

[0059] Example 11: A soft-pack battery was assembled using the positive electrode material in Example 10, and the light strip was lit.

[0060] Test results see Figure 11 The Gly@Zn||MnVO pouch cells successfully powered a single LED and a series-arranged light strip. These findings highlight the promising potential of Gly@Zn anodes in practical AZMBs.

Claims

1. An in-situ construction of a zinc-philic hydrophobic interface coating to achieve a stable Zn negative electrode, characterized in that A unique carbonyl functional interfacial layer was formed in situ by immersing zinc foil in glyoxal solution.

2. A sample for in-situ construction of a zinc-philic hydrophobic interface coating to achieve a stable Zn negative electrode according to claim 1, characterized in that The zinc foil is immersed in the solution to form a structure.

3. The solution according to claim 2, characterized in that The solution is a glyoxal solution.

4. The solution according to claim 2, characterized in that The soaking step is to soak the zinc foil in the glyoxal solution for 3 hours.

5. The aqueous zinc metal battery is characterized in that: The aqueous zinc metal battery comprises the relevant materials described in claims 1-4.

6. The zinc metal battery according to claim 5, characterized in that The zinc metal battery comprises a positive electrode, a separator, an electrolyte and a zinc negative electrode; the positive electrode material is a manganese-based material and a vanadium-based material; the manganese-based material is one or two of MnO2 and α-MnO2; the vanadium-based material is V2O5, VO2, MnVO and NH4V5O 10 One or more of the following: the membrane is a glass fiber membrane or a Celgard membrane; the zinc salt is any one of zinc sulfate, zinc chloride, zinc nitrate, zinc acetate, zinc phosphate, zinc trifluoromethanesulfonate, zinc bis(trifluoromethanesulfonylimide), zinc tetrafluoroborate, zinc hexafluorophosphate, and zinc bis(oxaloyl)borate, or a combination of at least two of the following: the zinc negative electrode is zinc foil or zinc powder.

7. The zinc metal battery according to claim 6, characterized in that The positive electrode is MnVO; the membrane is a glass fiber membrane; the solution is a 2 mol / L zinc sulfate solution; and the zinc negative electrode is zinc foil.

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