Zinc electrode materials and secondary batteries

Abstract

This application relates to the technical field of battery negative electrode materials, specifically disclosing a zinc electrode sheet material and a secondary battery. The zinc electrode sheet material has holes on its surface. The zinc electrode sheet material with holes on its surface can effectively inhibit dendrite growth, significantly extending the service life of a secondary battery using the zinc electrode sheet material as the negative electrode.

Description

Technical Field

[0001] The present application relates to the technical field of battery negative electrode materials, and in particular to a zinc electrode material and a secondary battery. Background Art

[0002] Currently, lithium-ion batteries are primarily used in power grid energy storage systems and as a primary source of power for transportation. As a high-performance secondary battery, lithium-ion batteries are widely used in various fields, including household appliances and office supplies. However, the source of metallic lithium, its safety, and its rising price have long been a focus of debate. As a result, an increasing number of manufacturers and research institutions are turning their attention to new secondary battery technologies.

[0003] Secondary zinc metal batteries have attracted widespread attention from manufacturers and scientific research institutions due to their advantages of low cost, high safety, environmental protection, and high energy density. Their good performance has great application prospects.

[0004] However, during the charge-discharge cycle of zinc metal batteries, uneven zinc deposition and the gradual formation of dendrites occur on the negative electrode side. As zinc dendrites continue to grow, they can eventually pierce the battery separator, causing direct contact between the positive and negative electrodes and a battery short circuit. Therefore, if zinc metal batteries are to be commercially produced, addressing the dendrite growth issue at the negative electrode is crucial to ensure battery cycling stability and reversibility. Summary of the Invention

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

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

[0007] A zinc pole piece material, wherein holes are provided on the surface of the zinc pole piece material.

[0008] Preferably, the average width of the holes is 1-10 μm, and the average depth of the holes is 10-20 μm.

[0009] Preferably, the ratio of the average depth to the average width of the holes is 1-10.

[0010] Preferably, the ratio of the average depth to the average width of the holes is 5-10;

[0011] Preferably, the ratio of the average depth to the average width of the holes is 5.

[0012] Preferably, the average depth of the holes is 10 μm and the average width is 2 μm.

[0013] Preferably, the method for forming the holes includes one of wet etching, 3D printing, template method, rolling method, and plasma etching method.

[0014] The second aspect is the application of the above zinc electrode material in the preparation of secondary battery negative electrode.

[0015] In a third aspect, the present application provides a secondary battery electrode, which adopts the following technical solution:

[0016] A secondary battery electrode comprises the above-mentioned zinc electrode material.

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

[0018] A secondary battery comprises the secondary battery electrode.

[0019] Fifthly, the application of the above-mentioned secondary batteries in electric vehicles, wearable devices, portable electronic devices and large-scale energy storage technology.

[0020] This application has the following beneficial effects:

[0021] The present application sets holes on the surface of the zinc electrode material. When the zinc electrode material is used as a zinc negative electrode, the holes on the zinc electrode material are conducive to the uniform distribution of the electric field on the surface of the zinc electrode material. At the same time, they can also form nucleation sites on the surface of the zinc electrode material, which facilitates the uniform deposition of zinc ions in the battery on the surface of the zinc electrode material, inhibits the growth of dendrites on the surface of the zinc electrode material, and extends the working life of the secondary battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a simulation diagram of the shape structure of the holes on the surface of the zinc electrode material and the electric field distribution in Example 1 of the present application;

[0023] Figure 2 This is a scanning electron microscope photograph of the zinc electrode material of Example 2 of the present application;

[0024] Figure 3 1 is a constant current charge and discharge curve diagram of a secondary battery assembled with the zinc electrode material of Example 1, Example 2 and Comparative Example 1 of the present application as the negative electrode;

[0025] Figure 4 This is a scanning electron microscope photograph of the zinc electrode material of Example 1 of the present application after being deposited as the negative electrode of a secondary battery for 1 hour;

[0026] Figure 5 This is a scanning electron microscope photograph of the zinc electrode material of Example 2 of the present application after being deposited as the negative electrode of a secondary battery for 1 hour. DETAILED DESCRIPTION

[0027] The present application is further described in detail below with reference to the accompanying drawings and examples.

[0028] Example 1

[0029] A zinc electrode material is prepared by the following steps: cutting zinc foil with a purity of 99.99% or greater 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 then drying the rinsed circular zinc sheets at room temperature. Uniform and dense holes are formed on the surface of the dried circular zinc sheets to obtain the zinc electrode material, wherein the average width of the holes is 1-10 μm, and in this embodiment, is set to 2 μm; the average depth of the holes is 10-20 μm, and in this embodiment, is set to 10 μm, and the ratio of the average depth to the average width of the holes is 5. In other embodiments, the average width of the holes can be 2 μm, and the average depth of the holes can be 20 μm, in which case the ratio of the average depth to the average width of the holes is 10.

[0030] The method for setting holes on the surface of the circular zinc sheet can be selected from wet etching, 3D printing, template method, rolling method, and plasma etching method. In this application, wet etching is selected. This method has low cost and is easy to control the width and depth of the hole structure.

[0031] Example 2

[0032] A zinc electrode material is prepared by the following steps: cutting a zinc foil with a purity of more than 99.99% 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, drying the rinsed circular zinc sheets at room temperature, and using a wet etching method to form uniform and dense holes on the surface of the dried circular zinc sheets to obtain the zinc electrode material, wherein the average width of the holes is 10 μm; the average depth of the holes is 10 μm, and the ratio of the average depth of the holes to the average width is 1.

[0033] Application Example 1

[0034] A secondary battery is assembled into a CR2025 type button secondary battery using the zinc electrode material in Example 1 as the secondary battery negative electrode, glass fiber as the separator, and a 2 mol / L zinc sulfate aqueous solution as the electrolyte.

[0035] Application Example 2

[0036] A secondary battery is assembled into a CR2025 type button secondary battery using the zinc electrode material in Example 2 as the secondary battery negative electrode, glass fiber as the separator, and a 2 mol / L zinc sulfate aqueous solution as the electrolyte.

[0037] Comparative Example 1

[0038] 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.

[0039] Comparative Application Example 1

[0040] A secondary battery is assembled into a CR2025 type button secondary battery using the zinc electrode material in comparative example 1 as the secondary battery negative electrode, glass fiber as a separator, and a 2 mol / L zinc sulfate aqueous solution as an electrolyte.

[0041] Performance testing

[0042] The structure of the holes in the zinc electrode material in Example 1 is shown in FIG. Figure 1 The surface scanning electron microscope photos and cross-sectional scanning electron microscope photos of the zinc electrode material in Example 2 are shown in FIG. Figure 2 As 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 surface of the zinc electrode material.

[0043] The zinc electrode materials in Example 1, Example 2 and Comparative Example 1 were applied to secondary batteries and tested using a Neware battery test system at 2.0 mA / cm 2 The deposition was carried out for 1 hour at a current density of 100 nm and the deposition morphology on the electrode surface was observed using a scanning electron microscope. Figure 3-Figure 5 As shown, Figure 3 The constant current charge and discharge curves of the zinc electrode materials in Example 1, Example 2 and Comparative Example 1 are applied to secondary batteries. Figure 4 This is a scanning electron microscope photograph of the zinc electrode material of Example 1 after being deposited as the negative electrode of a secondary battery for 1 hour. Figure 5 This is a scanning electron microscope photograph of the zinc electrode material of Example 2 after being deposited as the negative electrode of a secondary battery for 1 hour.

[0044] Combined with Example 1 and Figure 1 It can be seen that the average width of the holes on the surface of the zinc electrode material in Example 1 is 2 μm and the average depth is 10 μm, which shows that a hole structure with a specific depth and width can be set on the surface of the zinc sheet by wet etching. Figure 2 It can be seen that when the average width of the holes on the surface of the zinc electrode material is 10 μm, the width of the hole structure is relatively large, making it difficult to form a stable hole structure, and the surface of the zinc electrode material begins to be corroded, which is not conducive to the formation of nucleation sites on the surface of the zinc electrode material.

[0045] Combined with Example 1, Example 2 and Comparative Example 1 and Figure 3 It can be seen that when the zinc electrode sheet material in comparative example 1, in which a pore structure is not provided on the surface, is used as the negative electrode of a secondary battery, a short circuit occurs in the battery after 80 hours of cyclic charge and discharge. When the zinc electrode sheet material in Example 1 is used as the negative electrode of a secondary battery, a short circuit occurs in the battery after more than 260 hours of cyclic charge and discharge. When the zinc electrode sheet material in Example 2 is used as the negative electrode of a secondary battery, a short circuit occurs in the battery after more than 210 hours of cyclic charge and discharge. It can be seen that when the zinc electrode sheet material in Example 1 is used as the negative electrode of a secondary battery, the battery has a longer service life under cyclic charge and discharge. This shows that the pore structure of the zinc electrode sheet material in Example 1 is more conducive to inhibiting the growth of zinc negative electrode dendrites and improving the service life of the secondary battery. When the zinc electrode sheet materials in Examples 1 and 2 are used as the negative electrode of a secondary battery, the service life of the secondary battery is far longer than the service life of the zinc electrode sheet material in comparative example 1 as the negative electrode of a secondary battery, which shows that providing a uniform pore structure on the surface of the zinc sheet can be beneficial to inhibiting the growth of the diameter of the zinc negative electrode.

[0046] Combined with Example 1 and Example 2 Figure 1 、 Figure 4 as well as Figure 5 It can be seen that when the zinc electrode material in Example 1 is used as the zinc negative electrode of the secondary battery, the zinc ions in the electrolyte can be evenly deposited on the surface of the zinc electrode material. This shows that when the average width of the holes on the surface of the zinc electrode material is 2μm, the average depth is 10μm, and the ratio of the average depth to the average width is 5, it is more conducive to the uniform distribution of the electric field in the holes on the surface of the zinc electrode, and there is almost no electric field distribution inside the hole structure, so that the hole structure can serve as more and more uniform nucleation sites. These nucleation sites can induce zinc ions to be evenly deposited in the holes on the surface of the zinc electrode material, reducing the possibility of zinc ions growing dendrites at a certain part of the surface of the zinc electrode material, causing a short circuit in the secondary battery; at the same time, it avoids the filling of zinc deposited inside the hole, ensuring the uniform deposition of the zinc electrode surface under long-term cyclic charge and discharge, thereby extending the working life of the secondary battery when it is used as the zinc negative electrode.

[0047] When the zinc electrode material in Example 2 is used as the zinc negative electrode of the secondary battery, the zinc ions in the electrolyte are unevenly deposited on the surface of the zinc electrode material. This shows that when the average width of the pores on the surface of the zinc electrode material is 10 μm, the average depth is 10 μm, and the ratio of the average depth to the average width is 1, the electric field is distributed on the surface of the zinc electrode and inside the pores, causing the zinc ions in the electrolyte to be deposited on the surface of the zinc electrode material and in the pores. As the cyclic charge and discharge continues, the pore structure will gradually be filled with deposited zinc, which leads to a reduction in effective nucleation sites, thereby reducing the working life of the secondary battery when it is used as the zinc negative electrode compared to Example 1.

[0048] The present application sets up a uniform and dense pore structure on the surface of the zinc electrode material. When the zinc electrode material is used as the negative electrode of a secondary battery, the electric field can be evenly distributed on the surface of the zinc electrode material, thereby forming a uniform nucleation site on the surface of the zinc electrode material. Zinc ions can be deposited on the nucleation sites and thus evenly deposited on the surface of the zinc electrode material, thereby inhibiting the growth of dendrites on the surface of the zinc electrode material and improving the service life of the zinc secondary battery.

[0049] 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 negative electrode, characterized in that: The negative electrode of the secondary battery includes a zinc electrode sheet material. Holes are provided on the surface of the zinc electrode sheet material. The average depth of the holes is 10 μm and the average width is 2 μm.

2. The zinc electrode material according to claim 1, characterized in that: The method for forming the holes includes one of wet etching, 3D printing, template method, rolling method, and plasma etching method.

3. A secondary battery, characterized in that: The secondary battery negative electrode comprises the negative electrode according to any one of claims 1 to 2.

4. Application of the secondary battery according to claim 3 in the fields of electric vehicles, wearable devices, portable electronic devices and large-scale energy storage technology.

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