A method for modifying a zinc ion battery negative electrode based on a displacement reaction

Abstract

The application provides a zinc ion battery negative electrode modification method based on a displacement reaction, relates to the technical field of zinc ion batteries, and comprises the following steps: preparing a mixed displacement solution of sodium stannate and ascorbic acid; immersing a clean zinc foil into the mixed displacement solution, taking out after standing, washing and drying in line to obtain a zinc foil with SnO2 attached to the surface; and cutting the zinc foil with SnO2 attached to the surface into round pole pieces to obtain zinc ion battery negative electrode pieces. The displacement reaction method based on sodium stannate has the following advantages: the reaction is carried out in a solution at normal temperature and pressure, and only needs to immerse a zinc sheet into the solution to complete the reaction, so that the process is extremely simple, the cost is low, and the production is easy to scale up. More importantly, the SnO2 layer generated through the displacement reaction is in-situ grown through chemical bonding with the zinc substrate, the bonding force between the two is strong, the SnO2 layer is not easy to fall off or pulverize in a long-term cycle process, and the durability and effectiveness of the protective layer are guaranteed.

Description

Technical Field

[0001] This application relates to the field of zinc-ion battery technology, and more specifically, to a method for modifying the negative electrode of a zinc-ion battery based on a displacement reaction. Background Technology

[0002] With the decreasing availability of non-renewable energy sources, safe, low-cost, and high-efficiency energy storage technologies are crucial for the rational storage of renewable energy sources (such as wind, hydro, and solar power). Among various electrochemical energy storage systems, aqueous zinc-ion batteries stand out due to their inherent safety, abundant resources, good environmental compatibility, and high zinc metal anode capacity of up to 820 mAh g⁻¹. -1 With its theoretical specific capacity, it is considered one of the next-generation energy storage technologies that has the potential to replace lithium-ion batteries.

[0003] However, zinc metal anodes have long faced two interconnected core challenges in practical applications: First, the uneven distribution of zinc ions at the electrode / electrolyte interface can lead to uncontrolled growth of zinc dendrites, which can, in severe cases, puncture the separator and cause internal short circuits in the battery. Second, zinc is thermodynamically unstable in aqueous electrolytes, easily undergoing corrosion and accompanying hydrogen evolution reactions. This not only causes irreversible consumption of active materials but also leads to increased pH and byproduct deposition at the interface, thereby accelerating battery capacity decay and performance degradation. These problems are particularly pronounced under high-rate, long-cycle conditions, severely hindering the large-scale practical application of aqueous zinc-ion batteries.

[0004] Therefore, a method for modifying the negative electrode of a zinc-ion battery based on a displacement reaction is proposed to solve one of the aforementioned technical problems. Summary of the Invention

[0005] The purpose of this application is to provide a method for modifying the negative electrode of a zinc-ion battery based on a displacement reaction, which can solve at least one of the technical problems mentioned above. The specific solution is as follows:

[0006] According to a specific embodiment of this application, this embodiment provides a method for modifying a zinc-ion battery anode based on a displacement reaction, including:

[0007] Prepare a mixed displacement solution of sodium stannate and ascorbic acid;

[0008] The clean zinc foil is immersed in the mixed displacement solution, left to stand, then removed, rinsed and dried to obtain zinc foil with SnO2 on the surface.

[0009] Zinc foil with SnO2 on its surface is cut into round electrode sheets to obtain the negative electrode sheet of zinc-ion battery.

[0010] In some embodiments, the preparation of the mixed displacement solution of sodium stannate and ascorbic acid includes: adding sodium stannate and ascorbic acid to deionized water, stirring, and preparing the mixed displacement solution.

[0011] In some embodiments, a clean zinc foil is immersed in the mixed replacement solution and removed after standing for 10 minutes.

[0012] In some embodiments, the diameter of the zinc-ion battery negative electrode is 10 mm.

[0013] In some embodiments, 2.66 g of sodium stannate is used in the preparation of the 0.1 mol / ml mixed displacement solution.

[0014] In some embodiments, 1.76 g of ascorbic acid is used in the preparation of the 0.1 mol / ml mixed displacement solution.

[0015] Compared with the prior art, the above-described solutions of this application have at least the following beneficial effects:

[0016] The sodium stannate-based displacement reaction method used in this application has significant advantages: the reaction is carried out in a solution at room temperature and pressure, requiring only the zinc sheet to be immersed in the solution, making the process extremely simple, low-cost, and easy to scale up. More importantly, the SnO2 layer generated through the displacement reaction grows in situ with the zinc substrate through chemical bonding, resulting in strong adhesion between the two. This makes it less prone to detachment or pulverization during long-term cycling, ensuring the long-lasting effectiveness of the protective layer. Attached Figure Description

[0017] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. It is obvious that the drawings described below are merely some embodiments of this application, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort. In the drawings:

[0018] Figure 1 This invention provides a method for modifying the negative electrode of a zinc-ion battery based on a displacement reaction.

[0019] Figure 2 Comparison of scanning electron microscope images of zinc foil anode sheets containing SnO2 layers and unmodified pure zinc anode sheets prepared by the method provided in the embodiments of the present invention.

[0020] Figure 3 A comparison of the cycle performance of symmetrical batteries prepared from zinc foil negative electrode sheets containing SnO2 layers prepared by the method provided in this embodiment of the invention and unmodified pure zinc negative electrode sheets.

[0021] Figure 4 The full-cell cycle performance diagram of zinc foil containing SnO2 layer prepared by the method provided in the embodiments of the present invention as negative electrode || VO2 positive electrode. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this application clearer, the application will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0023] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that an article or device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such an article or device. Without further limitation, an element defined by the phrase "comprising one" does not exclude the presence of other identical elements in the article or device that includes said element.

[0024] To systematically address these issues, the key to this research lies in constructing a highly efficient and stable solid electrolyte interphase (SEI) layer on the surface of the zinc anode. The main functions of an ideal SEI layer are threefold: physical isolation, acting as a dense barrier to prevent direct contact between water and zinc, thus inhibiting corrosion at its source; ion regulation, providing uniform ion channels to guide planar zinc deposition and suppress dendrite formation; and environmental stabilization, reducing the generation of byproducts by consuming interfacial water or regulating the local chemical environment. Based on their formation mechanism, SEI layers are mainly classified into in-situ formed types and artificially constructed types.

[0025] This study used sodium stannate solution to construct a uniform and dense tin dioxide (SnO2) protective layer in situ on the surface of a zinc anode via a spontaneous displacement reaction. The core of this modification strategy lies in the fact that the generated SnO2 layer, through the synergistic effect of physical and chemical processes, fundamentally optimizes the interfacial environment for zinc deposition, thereby systematically improving the electrochemical performance of the zinc anode. First, the nanoscale dense structure of the SnO2 layer constructed in this study acts as a highly efficient physical barrier, significantly preventing direct and large-area contact between the zinc active surface and the electrolyte. This greatly reduces the reduction opportunities of water molecules on the zinc surface, thus effectively inhibiting hydrogen evolution. Simultaneously, this barrier also slows down the dissolution and irreversible corrosion process of zinc, providing a more stable working interface for the anode. Second, the growth of zinc dendrites originates from Zn... 2+ The unevenness of nucleation sites during initial deposition and the subsequent preferential growth effect at the tips are factors to consider. SnO2 is a widely proven material with a "zinc affinity." The SnO2 surface has a moderate adsorption energy for Zn atoms, which can significantly reduce Zn adsorption. 2+The initial nucleation overpotential of Zn. 2+ The nucleation site tends to uniformly nucleate on the SnO2 coating surface, rather than preferentially growing at defects or protrusions in the zinc substrate itself. During subsequent deposition, these uniformly distributed nanoscale nucleation sites guide the lateral two-dimensional spreading deposition of zinc, avoiding vertical growth in the three-dimensional direction, thus fundamentally suppressing dendrite formation and ensuring the long-term reversibility of the deposition / stripping process. Furthermore, compared to techniques such as physical vapor deposition and atomic layer deposition that require vacuum or high temperatures, the sodium stannate-based substitution reaction method used in this study has significant advantages.

[0026] The following is in conjunction with the appendix Figure 1-4 Detailed description of optional embodiments of the present invention.

[0027] According to specific embodiments of the present invention, this application provides a method for modifying the negative electrode of a zinc-ion battery based on a displacement reaction, such as... Figure 1 As shown, it includes:

[0028] S1: Prepare a mixed displacement solution of sodium stannate and ascorbic acid;

[0029] S2: Immerse the clean zinc foil in the mixed replacement solution, let it stand, take it out, rinse and dry it to obtain zinc foil with SnO2 on the surface;

[0030] S3: Cut the zinc foil with SnO2 coating onto its surface into circular electrode sheets to obtain the negative electrode sheet for zinc-ion batteries. The SnO2 has good electronic conductivity and chemical stability, which can homogenize the distribution of the zinc deposition electric field and inhibit dendrite growth; at the same time, ascorbic acid is green, environmentally friendly, and non-toxic; it significantly improves the cycle stability and coulombic efficiency of the zinc negative electrode, reduces zinc dendrite formation, hydrogen evolution, and corrosion, and extends battery life.

[0031] In some embodiments, the preparation of the mixed displacement solution of sodium stannate and ascorbic acid includes: adding sodium stannate and ascorbic acid to deionized water, stirring, and preparing the mixed displacement solution. The entire solution system is simple and pure, avoiding the introduction of impurity ions and ensuring the purity of SnO2; deionized water is a low-cost, safe, and environmentally friendly solvent.

[0032] In some embodiments, a clean zinc foil is immersed in the mixed displacement solution and removed after standing for 10 minutes. By controlling the displacement reaction time, the SnO2 layer thickness is made moderate, ensuring both protective effect and avoiding excessive thickness that would increase impedance, resulting in good process repeatability.

[0033] In some embodiments, the diameter of the zinc-ion battery negative electrode is 10 mm. The 10 mm is a standardized electrode size, compatible with conventional button cell molds, facilitating electrochemical performance testing and battery assembly.

[0034] In some embodiments, 2.66 g of sodium stannate is used in the preparation of the 0.1 mol / ml mixed displacement solution. By precisely controlling the concentration of the tin source, the displacement reaction is ensured to proceed fully, forming a completely covered SnO2 layer.

[0035] In some embodiments, 1.76 g of ascorbic acid is used in the preparation of the 0.1 mol / ml mixed displacement solution. By optimizing the redox reaction equilibrium through equimolar proportioning with sodium stannate, a dense and uniform SnO2 layer is obtained.

[0036] The specific implementation process of this method is as follows: 2.66 g of sodium stannate and 1.76 g of ascorbic acid are added to 100 ml of deionized water and stirred thoroughly to prepare a 0.1 mol / ml mixed displacement solution; then, the surface of the zinc foil is wiped clean and immersed in the mixed displacement solution. The SnO2 layer generated by the displacement reaction is removed after standing for 10 minutes, and the zinc foil with the SnO2 layer is rinsed clean with deionized water and then placed in an oven for drying; the dried zinc foil is cut into circular electrode sheets with a diameter of 10 mm to obtain an aqueous zinc-ion battery negative electrode sheet containing SnO2.

[0037] The performance of the battery was evaluated by assembling a CR2032 button cell under air conditions. Zinc foil containing a SnO2 layer was used as the negative electrode, 2 mol / L ZnSO4 solution was used as the electrolyte, and glass fiber filter membrane was used as the separator to assemble a symmetrical cell to test the cycle stability of the SnO2@Zn aqueous zinc-ion battery negative electrode.

[0038] Figure 2 Images of the zinc foil anode sheet containing a SnO2 layer and the unmodified pure zinc anode sheet prepared by the method of this embodiment, acquired by scanning electron microscopy. Figure 2 (a) shows the surface morphology of pure zinc sheet, exhibiting a smooth and dense metallic appearance, reflecting the original state of the unmodified zinc sheet surface. In comparison, Figure 2 (b) shows the surface of a zinc sheet with a SnO2 modified layer. The originally flat substrate is covered by a layer of nano-sized particles, indicating that SnO2 particles have been successfully generated in pure zinc to form a modified layer.

[0039] Figure 3 This image shows a comparison of the cycle performance of symmetrical batteries prepared using the zinc foil anode with a SnO2 layer prepared by the method described in this example, and an unmodified pure zinc anode. (At 5 mA cm⁻¹) -2 and 1mAh cm -2Under the specified test conditions, the pure zinc symmetric cell exhibited significant voltage polarization in the early stages of cycling, showing signs of failure after only about 120 hours. This indicates that the unmodified zinc anode under these conditions suffered from severe interfacial side reactions and dendrite growth, making it unable to maintain a stable zinc deposition process. In contrast, the SnO2@Zn-based symmetric cell showed a significantly reduced polarization voltage and achieved ultra-stable cycling for over 500 hours without significant polarization increase or short circuit. This demonstrates that the SnO2 modification layer optimized the zinc deposition behavior, suppressed dendrite growth and interfacial side reactions, and improved the long-term cycling stability of the zinc anode.

[0040] Figure 4 The diagram shows the cycle performance of a full cell prepared from a zinc foil||VO2 anode sheet containing a SnO2 layer, prepared by the method provided in this embodiment of the invention. The SnO2@Zn||VO2 full cell, assembled by matching the zinc foil anode sheet containing the SnO2 layer with a vanadium dioxide cathode, can achieve cycle performance in 0.1 A g... -1 It can stably cycle 100 times at a current density, demonstrating excellent cycle performance of a stable battery.

[0041] Finally, it should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the systems or apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the descriptions are relatively simple, and relevant parts can be referred to the method section.

[0042] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A method for modifying the negative electrode of a zinc-ion battery based on a displacement reaction, characterized in that, The method includes: Prepare a mixed displacement solution of sodium stannate and ascorbic acid; The clean zinc foil is immersed in the mixed displacement solution, left to stand, then removed, rinsed and dried to obtain zinc foil with SnO2 on the surface. Zinc foil with SnO2 on its surface is cut into round electrode sheets to obtain the negative electrode sheet of zinc-ion battery.

2. The method according to claim 1, characterized in that, The preparation of the mixed displacement solution of sodium stannate and ascorbic acid includes: adding sodium stannate and ascorbic acid to deionized water, stirring, and preparing the mixed displacement solution.

3. The method according to claim 1, characterized in that, Immerse a clean zinc foil in the mixed replacement solution and let it stand for 10 minutes before removing it.

4. The method according to claim 1, characterized in that, The diameter of the zinc-ion battery negative electrode is 10 mm.

5. The method according to claim 2, characterized in that, 2.66 g of sodium stannate was used in the preparation of the 0.1 mol / ml mixed displacement solution.

6. The method according to claim 2, characterized in that, 1.76 g of ascorbic acid was taken into the 0.1 mol / ml mixed displacement solution.

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