A preparation method and application of a three-dimensional zinc negative electrode for a zinc ion battery

Abstract

This invention relates to the field of aqueous zinc-ion battery technology, and discloses a method for preparing a three-dimensional zinc anode for zinc-ion batteries and its application. The method includes: placing a conductive substrate (used as a framework) and metallic zinc (used as a filler) into a roller press for composite pressing, so that zinc is embedded in the conductive substrate, obtaining a zinc / conductive substrate composite material; folding the zinc / conductive substrate composite material and continuing to place it into the roller press for further pressing, repeating this folding and pressing process multiple times to obtain a three-dimensional zinc anode with a smooth surface and uniform thickness. In this invention, the repeated rolling of the zinc foil can greatly increase the surface smoothness of the zinc anode and make the zinc crystal interface more compact, effectively reducing stress concentration during battery cycling, transforming major cracks into finer, multi-directional cracks, and achieving a uniform electric field distribution, thereby inducing uniform zinc deposition and significantly enhancing the stability of the zinc anode.

Description

Technical Field

[0001] This invention relates to the field of aqueous zinc-ion battery technology, specifically to a method for preparing and applying a three-dimensional zinc anode for zinc-ion batteries. Background Technology

[0002] Many studies focus on new renewable and clean energy sources such as solar, tidal, and wind power. However, these energy sources are intermittent and unstable, making it difficult to maintain a stable output. Batteries, as a highly efficient electrochemical energy storage device, have been widely used in grid-scale energy storage, electric vehicles, mobile communications, and many other fields.

[0003] Lithium-ion batteries, with their high energy density and high power density, have been widely used in various portable energy storage devices and new energy electric vehicles. However, lithium-ion batteries use organic electrolytes, which are toxic, flammable, and volatile, posing significant safety hazards. Therefore, researchers are exploring novel metal-ion batteries and optimizing their performance. Among various energy storage systems, aqueous zinc-ion batteries stand out due to their high theoretical capacity (820 mAh g⁻¹). -1 5855 mAh cm −3 Due to its low redox potential (-0.76 V vs. SHE) and environmentally friendly and safe characteristics, aqueous zinc-ion batteries have attracted widespread attention, making them one of the most promising energy storage technologies for practical applications. However, there are still two main problems with the zinc anode of aqueous zinc-ion batteries: Firstly, dendrites formed during cycling lead to low coulombic efficiency. Furthermore, the dendrites can break down the separator, causing short-circuit failure. The dendrites also have low adhesion to the metal substrate, easily detaching from the anode to form "dead zinc," reducing the utilization rate of the anode material. Secondly, the hydrogen evolution reaction on the zinc metal surface consumes water in the electrolyte, corrodes the metal anode surface, and the generated gas can cause battery gasification and electrolyte leakage.

[0004] Therefore, developing a simple, convenient, and feasible solution that can suppress zinc dendrite growth is key to the practical application of zinc-ion batteries. Summary of the Invention

[0005] The purpose of this invention is to provide a method for modifying the negative electrode of an aqueous zinc-ion battery. This method is simple and easy to operate. The application of this negative electrode can suppress the growth of zinc dendrites and improve the cycle life of the zinc-ion battery.

[0006] To achieve the above objectives, the present invention provides a method for preparing a three-dimensional zinc anode for zinc-ion batteries, characterized by comprising the following steps:

[0007] S1. The conductive substrate used as the skeleton and the metallic zinc used as the filler are placed in a roller press for roller pressing and compounding, so that the zinc is embedded in the conductive substrate to obtain a zinc / conductive substrate composite material.

[0008] S2. After folding the zinc / conductive substrate composite material, it is put into the roller press for rolling. This process is repeated multiple times to obtain a three-dimensional zinc anode with a flat surface and uniform thickness.

[0009] The conductive substrate is a mesh or foam structure with a mesh size of 200-400 mesh and a wire diameter of 0.08-0.2 mm, and the material is one or more of stainless steel, gold, silver, copper, aluminum, nickel, magnesium, conductive sponge, carbon fiber, and nickel foam; the zinc metal is one of zinc foil, zinc granules, and zinc powder.

[0010] As a further preferred embodiment of the present invention, the thickness of the three-dimensional zinc anode is 5~60 μm.

[0011] As a further preferred technical solution of the present invention, in steps S1 and S2, the thickness reduction value of each roll pressing is 5~20 μm.

[0012] As a further preferred technical solution of the present invention, the number of times the folding and rolling is repeated in step S2 is 2 to 10 times.

[0013] As a further preferred embodiment of the present invention, the purity of the zinc metal is 99.9%.

[0014] As a further preferred technical solution of the present invention, the zinc metal is zinc foil with a thickness of 10 μm to 200 μm. In step S1, the zinc foil is stacked on one or both sides of the conductive substrate and rolled.

[0015] As a further preferred embodiment of the present invention, the conductive substrate is one of stainless steel mesh, nickel mesh, copper mesh, aluminum mesh, magnesium mesh, silver mesh, aluminum mesh, and carbon fiber mesh.

[0016] According to a second aspect of the present invention, the present invention also provides a three-dimensional zinc anode for zinc-ion batteries, which is prepared by the above-described preparation method.

[0017] According to a third aspect of the invention, the invention also provides the application of a three-dimensional zinc anode for zinc-ion batteries in aqueous zinc-ion batteries.

[0018] Compared with the prior art, the present invention can achieve the following beneficial effects:

[0019] (1) The preparation process of the mechanically rolled zinc foil composite conductive material at room temperature used in this invention is simple to operate, has single and controllable conditions, and is easy to achieve large-scale production;

[0020] (2) In this invention, the surface flatness of the zinc anode can be greatly increased by repeatedly rolling the zinc foil, and the zinc crystal interface is made more compact, which effectively reduces the stress concentration problem during battery cycling, transforms the main cracks into finer, multi-directional cracks, and the electric field is evenly distributed, thereby inducing uniform zinc deposition and significantly enhancing the stability of the zinc anode.

[0021] (3) The three-dimensional zinc anode prepared by the method of the present invention is applied to zinc-ion batteries, and the zinc ion electrons have good electrochemical cycle stability. Attached Figure Description

[0022] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0023] Figure 1 The images show scanning electron microscope (SEM) images of the three-dimensional zinc anode and pure zinc foil prepared in Example 1.

[0024] Figure 2 The image shows the cycle performance of the symmetrical battery assembled with the three-dimensional zinc anode prepared in Example 1, with a symmetrical battery assembled with pure zinc foil as the control group.

[0025] Figure 3 The image shows the X-ray diffraction (XRD) pattern of the three-dimensional zinc anode prepared in Example 1 after cycling in a symmetrical cell, with a symmetrical cell assembled from pure zinc foil as a control group.

[0026] Figure 4 The full cell assembled with the three-dimensional zinc anode and iodine cathode prepared in Example 1 was tested at 2 A g. -1 Cyclic performance at charge / discharge current densities is shown, with an iodine cathode battery assembled from pure zinc foil serving as a control group.

[0027] The objectives, features, and advantages of this invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0028] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0029] Unless otherwise defined, the technical terms used in the following embodiments have the same meanings as commonly understood by those skilled in the art to which this invention pertains. Unless otherwise specified, the experimental reagents used in the following embodiments are conventional biochemical reagents; and the experimental methods described are conventional methods.

[0030] Example 1

[0031] This invention provides a method for preparing a zinc metal anode material, comprising the following steps:

[0032] (1) Take a 200 μm zinc foil (99.9% purity) and wipe it clean. Then put it into a mechanical roller press for rolling at room temperature. During the rolling process: adjust the roller press to 200 μm and start rolling. Adjust the roller press to reduce the thickness by 10 μm each time and roll the zinc foil evenly in the same direction until the thickness of the zinc foil is 40 μm. Then, fold the rolled zinc foil in half and put it into a roller press with a scale of 100 μm again for rolling. Adjust the roller press to reduce the thickness by 5 μm each time until the thickness of the zinc foil is 60 μm.

[0033] (2) Take a stainless steel mesh (300 mesh, wire diameter 0.04 mm, aperture 0.045 mm, size 4 cm * 4 cm) and sandwich it between two pieces of zinc foil (size 4 cm * 4 cm) after folding and rolling in step (1). Adjust the roller press to 200 μm and start rolling. Then adjust the roller press to reduce the thickness by 10 μm each time. Roll in the same direction until the thickness of the zinc / conductive substrate composite material is 60 μm.

[0034] (3) Fold (fold in half) the zinc / conductive substrate composite material obtained in step (2), adjust the roller press to 150 μm and start rolling, then adjust the roller press to reduce the thickness by 10 μm each time, and roll in the same direction until the thickness of the zinc / conductive substrate composite material is 60 μm. Repeat this folding and rolling 6 times to finally obtain a three-dimensional zinc anode with a flat surface and uniform thickness.

[0035] The following describes the characterization and electrochemical performance testing of the 60 μm thick three-dimensional zinc anode prepared in Example 1. Meanwhile, the 60 μm thick pure zinc foil after folding and rolling in step (1) was used as the electrode (Bare Zn) as the control group. The specific tests are as follows.

[0036] Scanning electron microscopy results of the negative electrode material are as follows: Figure 1 As shown. From Figure 1 As can be seen in image a, the surface of the blank zinc foil is irregular, while... Figure 1 In step (3) shown in bd, the three-dimensional zinc anode SS-Zn is repeatedly rolled and folded 2, 4, and 6 times. As the number of folding and rolling increases, the surface becomes smoother.

[0037] like Figure 2 As shown, compared to pure zinc electrodes, the three-dimensional zinc anode with a zinc / conductive substrate exhibits superior cycling performance, achieving a cycle life of up to 250 hours, a significant improvement. XRD tests were performed on the electrode after 50 cycles, as shown... Figure 3As shown, the three-dimensional zinc anode of Example 1 can induce the growth of (002) crystal planes. The deposition dominated by (002) crystal planes will be uniformly deposited in a direction parallel to the substrate, which will suppress the formation of zinc dendrites and effectively improve the performance of zinc-ion batteries.

[0038] like Figure 4 As shown, a three-dimensional zinc anode with a zinc / conductive substrate was used as the negative electrode, and iodine was used as the positive electrode to assemble a full cell for electrochemical performance testing. The results were obtained at 2 A g. -1 At a current density of up to 140 mAh g, its battery capacity reaches a high level. -1 It is evident that the cycle stability is significantly better than that of pure zinc foil / I2 batteries assembled using pure zinc foil.

[0039] Example 2

[0040] The negative electrode was prepared in basically the same way as in Example 1, except that the thickness of the final three-dimensional zinc negative electrode rolled in step (3) was adjusted to 50 μm.

[0041] Example 3

[0042] The negative electrode was prepared in basically the same way as in Example 1, except that the thickness of the final three-dimensional zinc negative electrode rolled in step (3) was adjusted to 40 μm.

[0043] Example 4

[0044] The negative electrode was prepared using a method essentially the same as that in Example 1, except that the stainless steel mesh in step (2) was replaced with a copper mesh.

[0045] Example 5

[0046] The negative electrode was prepared in basically the same way as in Example 1, except that the stainless steel mesh in step (2) was replaced with a nickel mesh.

[0047] Example 6

[0048] The negative electrode was prepared in essentially the same manner as in Example 1, except that the stainless steel mesh in step (2) was replaced with nickel foam.

[0049] Example 7

[0050] The negative electrode was prepared in basically the same way as in Example 1, except that the stainless steel mesh number in step (2) was replaced with 200 mesh.

[0051] The three-dimensional zinc anodes prepared in Examples 2-7 were tested according to the test method in Example 1. The results are shown in Table 1. It can be seen that the cycle stability is better than that of pure zinc foil / I2 battery.

[0052] Table 1 Comparison of battery performance parameters under the same test conditions

[0053]

[0054] While specific embodiments of the present invention have been described above, those skilled in the art should understand that these are merely illustrative examples, and various changes or modifications can be made to these embodiments without departing from the principles and essence of the present invention. The scope of protection of the present invention is defined only by the appended claims.

Claims

1. A method for preparing a three-dimensional zinc anode for zinc-ion batteries, characterized in that, Includes the following steps: S1. The conductive substrate used as the skeleton and the metallic zinc used as the filler are placed in a roller press for roller pressing and compounding, so that the zinc is embedded in the conductive substrate to obtain a zinc / conductive substrate composite material. S2. After folding the zinc / conductive substrate composite material, it is put into the roller press for rolling. This process is repeated multiple times to obtain a three-dimensional zinc anode with a flat surface and uniform thickness. The conductive substrate is a mesh or foam structure with a mesh size of 200-400 mesh and a wire diameter of 0.08-0.2 mm, and the material is one or more of stainless steel, gold, silver, copper, aluminum, nickel, magnesium, conductive sponge, carbon fiber, and nickel foam; the zinc metal is one of zinc foil, zinc granules, and zinc powder.

2. The method for preparing a three-dimensional zinc anode for a zinc-ion battery according to claim 1, characterized in that, The thickness of the three-dimensional zinc anode is 5~60 μm.

3. The method for preparing a three-dimensional zinc anode for a zinc-ion battery according to claim 1, characterized in that, In steps S1 and S2, the thickness reduction value for each roll pressing is 5~20 μm.

4. The method for preparing a three-dimensional zinc anode for a zinc-ion battery according to claim 1, characterized in that, In step S2, the folding and rolling are repeated 2 to 10 times.

5. The method for preparing a three-dimensional zinc anode for a zinc-ion battery according to claim 1, characterized in that, The purity of the zinc metal is 99.9%.

6. The method for preparing a three-dimensional zinc anode for a zinc-ion battery according to claim 1, characterized in that, The zinc metal is zinc foil with a thickness of 10 μm to 200 μm.

7. The method for preparing a three-dimensional zinc anode for a zinc-ion battery according to claim 1, characterized in that, In step S1, zinc foil is stacked on one or both sides of a conductive substrate and rolled.

8. The method for preparing a three-dimensional zinc anode for a zinc-ion battery according to claim 1, characterized in that, The conductive substrate is one of stainless steel mesh, nickel mesh, copper mesh, aluminum mesh, magnesium mesh, silver mesh, aluminum mesh, and carbon fiber mesh.

9. A three-dimensional zinc anode for zinc-ion batteries, characterized in that, It is prepared by the preparation method according to any one of claims 1-8.

10. The application of the three-dimensional zinc anode for zinc-ion batteries as described in claim 9 in aqueous zinc-ion batteries.

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