Preparation method and application of zinc electrode material

Abstract

This application relates to the field of zinc metal battery technology and specifically discloses a method for preparing a zinc electrode material and its application. The method comprises: immersing a zinc sheet in an etching solution, wherein the zinc sheet undergoes an oxidation-reduction reaction to obtain a zinc electrode material having a porous surface. The method has the advantages of low cost, high efficiency, and suitability for industrial production.

Description

Technical Field

[0001] The present application relates to the technical field of zinc metal batteries, and in particular to a preparation method and application of a zinc electrode material. Background Art

[0002] With the development of society, people's growing energy demand and awareness of environmental and climate degradation are driving and accelerating the global energy structure's transition from limited fossil fuels to efficient energy storage systems based on electrochemical reactions. An increasing number of manufacturers and research institutions are investing in battery production and research. In the battery field, zinc metal batteries have attracted significant attention due to its excellent stability in aqueous solutions, low cost, high natural abundance, high yield, non-toxicity, and environmental friendliness.

[0003] In the production and preparation of zinc batteries, zinc sheets are typically used as electrodes. However, the surface of the original zinc sheet has a passivating oxide layer, which slows the surface dynamics when used as an electrode. In addition, the flat and smooth surface of the original zinc sheet also provides fewer effective nucleation sites. Therefore, some researchers have formed a three-dimensional pore structure on the surface of the zinc metal negative electrode to increase the electrochemical active area, improve surface wettability, increase the number of nucleation sites, and inhibit electrode shape changes, thereby improving the electrochemical performance of the zinc negative electrode and the performance of the zinc metal battery.

[0004] Currently, methods for forming porous structures on zinc electrode surfaces primarily include template processing, sintering, rolling, plasma etching, and 3D printing. However, these methods are costly and complex, hindering industrial production and commercial application. Therefore, a simple, low-cost method for preparing zinc electrode materials is needed. Summary of the Invention

[0005] In order to solve the above technical problems, the present application provides a preparation method and application of zinc electrode material.

[0006] In a first aspect, the present application provides a method for preparing a zinc electrode material, which adopts the following technical solution:

[0007] A method for preparing a zinc pole piece material comprises: immersing a zinc piece in an etching solution, and obtaining a zinc pole piece material with a porous surface after the zinc piece undergoes an oxidation-reduction reaction.

[0008] Preferably, the etching solution is a trivalent chromium aqueous solution.

[0009] Preferably, the trivalent chromium aqueous solution is a mixture of one or more of a chromium chloride aqueous solution, a chromium nitrate aqueous solution, and a chromium sulfate aqueous solution.

[0010] Preferably, the concentration of trivalent chromium ions in the trivalent chromium aqueous solution is 0.01 mol / L-2 mol / L;

[0011] Preferably, the concentration of trivalent chromium ions in the trivalent chromium aqueous solution is 0.1 mol / L-2 mol / L;

[0012] Preferably, the concentration of trivalent chromium ions in the trivalent chromium aqueous solution is 1 mol / L.

[0013] Preferably, the oxidation-reduction reaction time is 3-8 minutes; preferably, the oxidation-reduction reaction time is 5 minutes.

[0014] Preferably, the zinc electrode material with a porous surface includes a zinc electrode material with a porous surface on one side or porous surfaces on both sides.

[0015] In a second aspect, the present application provides a zinc electrode material, which adopts the following technical solution:

[0016] A zinc electrode material is prepared by the above method.

[0017] In a third aspect, the present application provides a secondary battery electrode, which adopts the following technical solution:

[0018] A secondary battery electrode comprises the above-mentioned zinc electrode material.

[0019] In a fourth aspect, the present application provides a secondary battery, which adopts the following technical solution:

[0020] A secondary battery comprises the secondary battery electrode.

[0021] Fifthly, the application of the above-mentioned secondary batteries in electric vehicles, wearable devices, portable electronic devices and large-scale energy storage technology.

[0022] This application has the following beneficial effects:

[0023] 1. In this application, the zinc sheet is immersed in an etching solution, and uniform and dense holes can be formed on the surface of the zinc sheet through an oxidation-reduction reaction. This method is simple to operate, low in cost, and easy to apply to industrial production.

[0024] 2. This application uses a trivalent chromium aqueous solution as an etching solution. The trivalent chromium aqueous solution undergoes an oxidation-reduction reaction with the surface of the zinc sheet to form holes on the surface of the zinc sheet. The trivalent chromium aqueous solution is not easy to leave impurity compounds on the surface of the zinc sheet and in the holes, thereby improving the product quality of the zinc electrode material. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 1 is an XRD pattern of the zinc electrode material prepared in Example 1 and Comparative Example 1 of the present application;

[0026] Figure 2The scanning electron microscope photographs of the reaction surface and cross-section of the zinc electrode material prepared in Example 1 of the present application are shown;

[0027] Figure 3 These are scanning electron microscope photos of the reaction surface and cross-section of the zinc electrode material prepared in Example 2 of the present application;

[0028] Figure 4 This is a scanning electron microscope photograph of the reaction surface of the zinc electrode material prepared in Example 3 of the present application;

[0029] Figure 5 This is a scanning electron microscope photograph of a cross section of the zinc electrode material prepared in Example 3 of the present application;

[0030] Figure 6 These are scanning electron microscope photos of the reaction surface and cross-section of the zinc electrode material prepared in Example 4 of the present application;

[0031] Figure 7 This is a cyclic voltammogram of the zinc electrode material prepared in Example 3 of the present application applied to a rechargeable battery. DETAILED DESCRIPTION

[0032] The present application is further described in detail below with reference to the accompanying drawings and examples.

[0033] A method for preparing a zinc electrode material comprises immersing a zinc sheet in an etching solution, and subjecting the zinc sheet to an oxidation-reduction reaction to obtain a zinc electrode material having a porous surface. The method specifically comprises the following steps:

[0034] (1) Cut the zinc foil into round zinc sheets.

[0035] In this step, the zinc foil can be cut into zinc sheets of other geometric shapes, such as rectangle, oval, triangle, etc. as needed.

[0036] (2) Rinse and dry the cut circular zinc sheets.

[0037] (3) The dried circular zinc sheet is immersed in an etching solution for redox reaction and then taken out, and then rinsed and dried to obtain a zinc electrode material with a porous surface.

[0038] The etching solution in this step is a trivalent chromium aqueous solution. Specifically, the trivalent chromium aqueous solution can be a mixture of one or more of a chromium chloride aqueous solution, a chromium nitrate aqueous solution, and a chromium sulfate aqueous solution. Because the trivalent chromium ions undergo a redox reaction with the circular zinc flakes, the anion can be arbitrarily selected. In this application, the etching solution is a chromium chloride aqueous solution.

[0039] In the present application, as needed, the surface of the circular zinc sheet can be subjected to an oxidation-reduction reaction on one side to obtain a zinc electrode material with a porous side, or the surface of the circular zinc sheet can be subjected to an oxidation-reduction reaction on both sides to obtain a zinc electrode material with porous sides. In the present application, the surface of the circular zinc sheet is subjected to an oxidation-reduction reaction on one side to obtain a zinc electrode material with a porous side.

[0040] In the present application, the redox reaction time of the circular zinc sheet in the etching solution can be selected as needed, specifically 3-8 minutes. When the redox reaction time is less than 3 minutes, the degree of redox reaction is low, and fewer holes are generated on the surface of the circular zinc sheet; when the redox reaction time is higher than 8 minutes, the degree of redox reaction is high, and the surface of the circular zinc sheet may be corroded, and the holes are too large, resulting in an unstable hole structure. In the present application, the redox reaction time is preferably 5 minutes.

[0041] The zinc electrode material prepared in the present application can be used for the negative electrode in a zinc metal secondary battery, and the zinc metal secondary battery can be applied to technical fields such as electric vehicles, wearable devices, portable electronic devices and large-scale energy storage.

[0042] Example 1

[0043] A method for preparing a zinc electrode material comprises the following steps:

[0044] Zinc foil with a purity of more than 99.99% and a thickness of 0.1 mm is cut into round zinc sheets with a diameter of 16 mm.

[0045] The cut circular zinc sheet is rinsed with propanol or ethanol, and then dried at room temperature.

[0046] One side of the dried circular zinc sheet was covered with a sealing film, and then the circular zinc sheet with the sealing film was immersed in a 0.01 mol / L chromium chloride aqueous solution for an oxidation-reduction reaction. The reaction time was 5 minutes. The zinc sheet after the reaction was taken out and rinsed with deionized water. After drying at room temperature, a zinc electrode material with a porous surface was obtained.

[0047] Example 2

[0048] A method for preparing a zinc electrode material comprises the following steps:

[0049] Zinc foil with a purity of more than 99.99% and a thickness of 0.1 mm is cut into round zinc sheets with a diameter of 16 mm.

[0050] The cut circular zinc sheet is rinsed with propanol or ethanol, and then dried at room temperature.

[0051] One side of the dried circular zinc sheet was covered with a sealing film, and then the circular zinc sheet with the sealing film was immersed in a 0.1 mol / L chromium chloride aqueous solution for redox reaction. The reaction time was 5 minutes. The zinc sheet after the reaction was taken out and rinsed with deionized water. After drying at room temperature, a zinc electrode material with a porous surface was obtained.

[0052] Example 3

[0053] A method for preparing a zinc electrode material comprises the following steps:

[0054] Zinc foil with a purity of more than 99.99% and a thickness of 0.1 mm is cut into round zinc sheets with a diameter of 16 mm.

[0055] The cut circular zinc sheet is rinsed with propanol or ethanol, and then dried at room temperature.

[0056] One side of the dried circular zinc sheet was covered with a sealing film, and then the circular zinc sheet with the sealing film was immersed in a 1 mol / L chromium trichloride hexahydrate aqueous solution for an oxidation-reduction reaction. The reaction time was 5 minutes. The zinc sheet after the reaction was taken out and rinsed with deionized water. After drying at room temperature, a zinc electrode material with a porous surface was obtained.

[0057] Example 4

[0058] A method for preparing a zinc electrode material comprises the following steps:

[0059] Zinc foil with a purity of more than 99.99% and a thickness of 0.1 mm is cut into round zinc sheets with a diameter of 16 mm.

[0060] The cut circular zinc sheet is rinsed with propanol or ethanol, and then dried at room temperature.

[0061] One side of the dried circular zinc sheet was covered with a sealing film, and then the circular zinc sheet with the sealing film was immersed in a 2 mol / L chromium trichloride hexahydrate aqueous solution for an oxidation-reduction reaction. The reaction time was 5 minutes. The zinc sheet after the reaction was taken out and rinsed with deionized water. After drying at room temperature, a zinc electrode material with a porous surface was obtained.

[0062] Comparative Example 1

[0063] A method for preparing a zinc electrode material comprises the following steps: cutting a zinc foil with a purity of 99.99% or more and a thickness of 0.1 mm into circular zinc sheets with a diameter of 16 mm; rinsing the cut circular zinc sheets with propanol or ethanol; and drying the rinsed circular zinc sheets at room temperature to obtain the zinc electrode material.

[0064] Performance testing

[0065] The zinc electrode materials prepared in Example 3 and Comparative Example 1 were tested using an XRD diffractometer. The obtained XRD test pattern is as follows: Figure 1 The zinc electrode material prepared in Example 1-4 was subjected to a scanning electron microscope to obtain its morphology. The morphology of the zinc electrode material prepared in Example 1-4 is shown in FIG. Figure 2-6 As shown, Figure 2 The scanning electron microscope photos of the reaction surface and cross-section of the zinc electrode material prepared in Example 1 are shown. Figure 2 The smaller photo in the upper right corner is a cross-sectional scanning electron microscope photo. Figure 2 The larger photo is a scanning electron microscope photo of the reaction surface. Figure 3 The scanning electron microscope photos of the reaction surface and cross-section of the zinc electrode material prepared in Example 2 are shown. Figure 3 The smaller photo in the upper right corner is a cross-sectional scanning electron microscope photo. Figure 3 The larger photo is a scanning electron microscope photo of the reaction surface. Figure 4 This is a scanning electron microscope photograph of the reaction surface of the zinc electrode material prepared in Example 3 of the present application. Figure 4 The smaller photo in the upper right corner is a scanning electron microscope photo with a scale of 10 μm. Figure 4 The larger photo is a scanning electron micrograph with a scale of 150 μm. Figure 5 This is a scanning electron microscope photograph of the cross section of the zinc electrode material prepared in Example 3 of the present application. Figure 6 The scanning electron microscope photos of the reaction surface and cross-section of the zinc electrode material prepared in Example 4 are shown. Figure 6 The smaller photo in the upper right corner is a cross-sectional scanning electron microscope photo. Figure 6 The larger photo is a scanning electron microscope photo of the reaction surface.

[0066] Combined with Example 3 and Comparative Example 1 and Figure 1 As can be seen, both Example 3 and Comparative Example 1 correspond to the standard card of elemental zinc and are not affected by impurities. This indicates that after the redox reaction between the zinc sheet and trivalent chromium ions, no other impurity compounds adhere to the surface of the zinc sheet or enter the pores on the zinc sheet surface. The reaction of trivalent chromium ions with the zinc sheet to form pores on the zinc sheet surface does not introduce impurity effects, thereby improving the product quality of the zinc electrode material.

[0067] Combined with Examples 1-4 and Figure 2-6It can be seen that the reaction of trivalent chromium ions with zinc sheets can form holes on the surface of the zinc sheet, and as the concentration of trivalent chromium ions increases, the number of holes on the surface of the zinc sheet gradually increases, and the width of the holes formed on the surface of the zinc sheet also increases. Here, the width refers to the distance between the hole cracks. This shows that by changing the concentration of trivalent chromium ions, the width and depth of the holes on the surface of the zinc electrode material can be controlled. Figure 4 and Figure 5 It can be seen that when the concentration of trivalent chromium ions is 1 mol / L, the pores formed on the surface of the zinc electrode material are more uniform and dense, and can form stable pores with a certain structure. The average width of the pores is 2μm, the average depth of the pores is 10-20μm, and the ratio of the average depth to the average width of the pores is 5-10. When the concentration of trivalent chromium ions is 0.1 mol / L, the pores formed on the surface of the zinc electrode material are fewer and more scattered, and the average width and average depth of the pores are both less than 1μm. When the concentration of trivalent chromium ions is 2 mol / L, due to the high concentration of trivalent chromium ions, many larger pores are formed on the surface of the zinc sheet. The average width of the pores is 10μm, the average depth of the pores is 10μm, and the ratio of the average depth to the average width of the pores is 1. The surface of the zinc electrode material begins to corrode. This shows that when the concentration of trivalent chromium ions is 1 mol / L, it is more conducive to the formation of uniform, dense and structurally stable pores on the surface of the zinc electrode material.

[0068] The zinc electrode materials prepared in Examples 1-4 and Comparative Example 1 were used as zinc electrodes to assemble CR2025 type button symmetrical batteries. The cyclic voltammetry curves of the above symmetrical batteries were tested using an EC-Lab electrochemical workstation. The experimental results are as follows: Figure 7 shown.

[0069] Combined with Examples 1-4 and Comparative Example 1 and Figure 7 It can be seen that compared with Comparative Example 1, when the zinc electrode materials prepared in all examples are applied to symmetrical batteries, the cathode negative sweep onset potential of the zinc electrode is more positive, and the anode positive sweep onset potential is more negative, indicating improved electrode kinetics. Furthermore, as the trivalent chromium ion concentration increases, the cyclic voltammetric current of the zinc electrode increases accordingly, indicating that the three-dimensional pore structure on the surface of the zinc electrode material prepared in this application increases the electrode active area and active sites, further facilitating the cyclic use of the symmetrical battery.

[0070] The present application adopts trivalent chromium ions to undergo an oxidation-reduction reaction with zinc sheets to prepare zinc electrode materials. The preparation method is simple and has low cost. In addition, the pore structure on the surface of the zinc electrode material can be controlled by controlling the concentration of trivalent chromium ions, so that the depth-to-width ratio of the pore structure on the surface of the zinc electrode material can be adjusted, making it more suitable as an electrode in a zinc secondary battery.

[0071] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A secondary battery electrode, characterized in that: include: A zinc electrode material is prepared by the following preparation method, comprising: immersing a zinc sheet in an etching solution, wherein the zinc sheet undergoes an oxidation-reduction reaction to obtain a zinc electrode material with a porous surface, wherein the etching solution is a trivalent chromium aqueous solution, and the concentration of trivalent chromium ions in the trivalent chromium aqueous solution is 0.01 mol / L-2 mol / L; and the oxidation-reduction reaction time is 3-8 minutes.

2. The secondary battery electrode according to claim 1, wherein The trivalent chromium aqueous solution is a mixture of one or more of a chromium chloride aqueous solution, a chromium nitrate aqueous solution, and a chromium sulfate aqueous solution.

3. The secondary battery electrode according to claim 1, wherein The concentration of trivalent chromium ions in the trivalent chromium aqueous solution is 0.1 mol / L-2 mol / L.

4. The method for preparing the zinc electrode material according to claim 1, characterized in that: The concentration of trivalent chromium ions in the trivalent chromium aqueous solution is 1 mol / L.

5. The secondary battery electrode according to claim 1, wherein The oxidation-reduction reaction time is 5 minutes.

6. The secondary battery electrode according to claim 1, characterized in that The zinc electrode material with a porous surface includes a zinc electrode material with a porous surface on one side or porous surfaces on both sides.

7. A secondary battery, characterized in that: The secondary battery electrode according to claim 6 is included.

8. Application of the secondary battery according to claim 7 in the fields of electric vehicles, wearable devices, portable electronic devices and large-scale energy storage technology.

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