Preparation method of zinc foil for inhibiting growth of zinc dendrites

Abstract

The invention discloses a zinc foil preparation method for inhibiting zinc dendritic crystal growth, which comprises the following steps: carrying out laser texturing treatment on the surface of a pure zinc foil to generate a high-density ordered micro-pit array structure on the surface of the zinc foil, thereby greatly increasing the number of active sites on the surface of the zinc foil and eliminating the defects of scratches, pits and the like generated by the zinc foil; and carrying out alloying treatment on the zinc foil and a CuCl2 solution to generate a CuZn5 alloy layer so as to obtain the zinc foil for inhibiting dendritic crystal growth. The high-density ordered micro-pit array structure on the surface of the zinc foil eliminates the structural defects of the zinc foil, the increase of active sites and the introduction of the CuZn5 alloy layer can significantly reduce the desolventizing energy barrier in the charge transfer process and promote the Zn deposition / dissolution kinetics on the surface of the negative electrode, so that few by-products are formed in the treated negative electrode, and the service life of the negative electrode is prolonged. Therefore, the cycle performance of the treated zinc foil after the zinc foil forms a button cell is greatly improved, the service life of the zinc foil is obviously prolonged, and the economic benefit is particularly obvious.

Description

Technical Field

[0001] The invention belongs to the technical field of zinc ion battery energy storage, and in particular relates to a method for preparing zinc foil for inhibiting the growth of zinc dendrites. Background Art

[0002] With the development of the global economy and the increase in population, society's demand for energy continues to rise. Energy storage technology is crucial to the effective use of renewable energy, balancing energy supply and demand, and improving energy efficiency. As an energy storage technology, aqueous zinc-ion batteries have great development potential and can play an important role in the field of energy storage to meet the growing demand for energy. Although the widely used lithium-ion batteries have high energy density and good performance, they have major safety issues. For example, thermal runaway or even explosion may occur in the case of overcharging or overheating. In addition, the reserves of lithium metal resources are limited and unevenly distributed, resulting in high costs, which limits the application of lithium-ion batteries in large-scale energy storage.

[0003] Zinc is an abundant metal element that is widely distributed on the earth and relatively cheap. With the increasing global attention to environmental protection, energy storage technology needs to meet environmental protection requirements. Aqueous zinc-ion batteries use water as the electrolyte, which is environmentally friendly and does not have problems such as leakage of organic electrolytes that may cause environmental pollution. At the same time, aqueous electrolytes are non-flammable and non-explosive, which improves the safety of the battery. However, in actual applications, the formation of zinc dendrites and side reactions in water (e.g., hydrogen evolution and corrosion) seriously affect the stability and life of aqueous zinc-ion batteries. In addition, in recent years, scientific researchers have introduced strategies to optimize electrolytes through continuous research, but have introduced expensive and environmentally unfriendly salts, which runs counter to the development of aqueous zinc-ion batteries. Summary of the invention

[0004] The present invention provides a method for preparing zinc foil for inhibiting the growth of zinc dendrites to solve the above technical problems, and the method has the advantages of novel technology, convenient operation, low cost, etc.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A method for preparing a zinc foil surface for inhibiting zinc dendrite growth comprises the following steps: performing surface laser texturing treatment on the zinc foil by a laser cutting machine to produce a high-density ordered micro-pit array structure on the surface of the zinc foil, thereby increasing the number of surface active sites and eliminating scratches and pit defects generated by the zinc foil itself; then, the zinc foil is immersed in a CuCl2 solution and alloyed to produce a CuZn5 alloy layer, thereby obtaining the zinc foil for inhibiting zinc dendrite growth.

[0007] Preferably, the thickness of the zinc foil is 0.05 mm.

[0008] Preferably, the laser cutting machine has the following parameters: speed of 1800 mm / s, current of 1 A, frequency of 170 kHz, pulse width of 1 μm, and the unit diameter of the high-density ordered micro-pit array structure finally produced is 10 μm and the depth is 4.5 μm.

[0009] Preferably, the concentration of the CuCl2 solution is 0.05 mol / L.

[0010] Preferably, the alloying treatment is to place the zinc foil after surface laser texturing in a CuCl2 solution for 1 minute.

[0011] Compared with the prior art, the present invention has the following main advantages:

[0012] 1. The present invention uses a laser cutting machine to perform surface laser texturing on zinc foil, which is extremely simple to operate, and has great guarantees for speed and quality. This method is very easy to operate in the specific zinc negative electrode production process.

[0013] 2. The present invention achieves the effect of surface alloying through simple treatment and extremely simple immersion treatment. The CuCl2 material involved is low in cost (0.01 mol / L, 0.0298$ / L), and the production efficiency is extremely high and the cost is very low.

[0014] 3. Surface laser texturing technology can produce a high-density ordered micro-pit array structure on the surface of the zinc foil, increase the number of active sites on the surface of the zinc foil, and eliminate defects such as scratches and pits generated by the zinc foil itself.

[0015] 4. After surface alloying treatment, a uniform CuZn5 alloy layer can be produced on the surface of the zinc foil after surface laser treatment. CuZn5 will preferentially attract zinc atoms during the cycle, significantly reduce the desolvation energy barrier of the charge transfer process, and promote the Zn deposition / dissolution kinetics on the negative electrode surface, thereby reducing the by-products formed in the treated negative electrode. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is the preparation process of the LT-Zn@CuZn5 electrode prepared in Example 1 of the present invention;

[0017] Figure 2 This is a front scanning electron microscope image of the LT-Zn@CuZn5 electrode prepared in Example 1 of the present invention;

[0018] Figure 3 is an X-ray diffraction image of the LT-Zn@CuZn5 electrode prepared in Example 1 of the present invention;

[0019] Figure 4It is a charge-discharge cycle curve diagram of a symmetrical battery assembled from the LT-Zn@CuZn5 electrode prepared in Example 1 of the present invention;

[0020] Figure 5 This is an in-situ electroplating optical picture of the LT-Zn@CuZn5 electrode prepared in Example 1 of the present invention;

[0021] Figure 6 is a relationship diagram between the potential and the exchange current density of the LT-Zn@CuZn5 electrode prepared in Example 1 of the present invention during the cycle;

[0022] Figure 7 It is a display diagram of an asymmetric battery assembled by the LT-Zn@CuZn5 electrode prepared in Example 1 of the present invention and the I / Mo2C@CN cathode prepared in Application Example 1;

[0023] Figure 8 It is a capacity curve diagram of an asymmetric battery assembled by the LT-Zn@CuZn5 electrode prepared in Example 1 of the present invention and the I / Mo2C@CN cathode prepared in Application Example 1;

[0024] Fig. 9 It is a graph of the cycle performance and coulombic efficiency of an asymmetric battery assembled by the LT-Zn@CuZn5 electrode prepared in Example 1 of the present invention and the I / Mo2C@CN cathode prepared in Application Example 1. DETAILED DESCRIPTION

[0025] In order to more clearly understand the above-mentioned objects, features and advantages of the present invention, the present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that, in the absence of conflict, the embodiments of the present application and the features in the embodiments can be combined with each other. In the following description, many specific details are set forth in order to fully understand the present invention, and the embodiments described are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in the art without making creative work are within the scope of protection of the present invention.

[0026] Example 1

[0027] A method for preparing zinc foil for inhibiting zinc dendrite growth, see Figure 1-9, including the following steps: using a laser cutting machine to perform surface laser texturing on the zinc foil, the parameters of the laser cutting machine used for the zinc foil are: speed (mm / s): 1800; current (A): 1; frequency (kHz): 170; Q pulse width (μm): 1, and finally a high-density ordered micro-pit array structure is produced, with a unit diameter of 10μm and a depth of 4.5μm, which increases the number of surface active sites and eliminates scratches and pits generated by the zinc foil itself, thereby obtaining a LT-Zn electrode. Then, an alloying treatment is performed, that is, the zinc foil treated in the previous step is immersed in a 0.05mol / L CuCl2 solution for 1min to produce a CuZn5 alloy layer, thereby obtaining a zinc foil for inhibiting the growth of zinc dendrites, namely, a LT-Zn@CuZn5 electrode.

[0028] A preparation method of a LT-Zn@CuZn5 button symmetrical battery: the LT-Zn@CuZn5 electrode obtained by the above steps is punched into a disc with a diameter of 14 mm using a specified mold, a piece of glass fiber filter paper is added between two LT-Zn@CuZn5 electrodes as a diaphragm, and a 2 mol / L zinc sulfate aqueous solution is added to the diaphragm as a liquid electrolyte, the above device is assembled in a CR2032 battery shell, and the LT-Zn@CuZn5 button symmetrical battery is obtained by packaging it using a button battery press under air conditions.

[0029] Figure 2 This is a front scanning electron microscope image of the LT-Zn@CuZn5 electrode of the present invention, which shows that a high-density ordered micro-pit array structure is successfully generated on the surface of the Zn foil by surface laser texturing technology; Figure 3 This is an X-ray diffraction image of LT-Zn@CuZn5 of the present invention, proving that CuZn5 alloy is produced on the surface of zinc foil after laser texturing through alloying treatment; Figure 4 The charge-discharge cycle curves of the symmetrical battery assembled with the LT-Zn@CuZn5 electrode of the present invention prove that the prepared anode has stable electrochemical performance under various current (3-10mA cm-2) and deposition capacity (1-2.5mAh cm-2) conditions; Figure 5 This is an in-situ electroplating optical picture of the LT-Zn@CuZn5 electrode of the present invention, and the behavior of the prepared LT-Zn@CuZn5 negative electrode without dendrite growth during in-situ electroplating and stripping can be observed under macroscopic conditions; Figure 6 It is a relationship diagram between the potential and the exchange current density in the cycle of the LT-Zn@CuZn5 electrode of the present invention, which shows that the prepared anode significantly reduces the desolvation energy barrier of the charge transfer process and promotes the Zn deposition / dissolution kinetics on the negative electrode surface, thereby reducing the by-products formed in the treated negative electrode.

[0030] Application Example 1

[0031] Preparation of a button-type zinc-iodine battery. The preparation process of the battery is the same as that of Example 1; the difference is that the asymmetric zinc-iodine battery integration can effectively realize energy storage and voltage output;

[0032] Step 1, preparation of Mo2C@CN: Dissolve 0.8g of ammonium molybdate tetrahydrate in 40ml of methanol solution, and obtain a brown mixed solution after dissolution with magnetic stirring. Then, add 5ml of ammonia water to the brown mixed solution and stir at room temperature to obtain a red solution. Wash the red solution with deionized water and ethanol to obtain a precipitate. Dry in a vacuum drying oven for 24 hours to obtain a purple Mo precursor powder. Finally, heat the Mo precursor powder in a tube furnace at 1500℃ for 1h, and finally name the black powder Mo2C-CN.

[0033] Step 2, preparation of I / Mo2C@CN cathode: Using N-methylpyrrolidone as solvent, polyvinylidene fluoride, Ketjen black, and active material (black powder Mo2C-CN prepared in the previous step) are added in a mass ratio of 1:1:8 and stirred evenly to obtain slurry, which is evenly coated on a circular titanium mesh with a diameter of 14 mm and dried in an oven at 80 degrees Celsius for 4 hours. The titanium mesh coated with slurry and dried is placed in an electrolytic cell with a solution of 1 mol / L ZnI, and iodine is plated at a current of 0.05A for 300s through the chronopotentiometric working program in the electrochemical workstation, and finally the I / Mo2C@CN cathode is obtained.

[0034] Step 3: The method of Example 1 is the same as that of Example 1, using a specified mold to punch out LT-Zn@CuZn5 electrodes to prepare zinc anodes;

[0035] Step 4: Assemble the obtained electrodes into button-type batteries under air conditions in the same manner as in Example 1.

[0036] Figure 7 This is a display diagram of an asymmetric battery assembled from the LT-Zn@CuZn5 electrode and the I / Mo2C@CN cathode of the present invention. The stable voltage output proves the successful preparation of the asymmetric battery. Figure 8 This is the capacity curve of the asymmetric battery assembled by the LT-Zn@CuZn5 electrode of the present invention and the I / Mo2C@CN cathode. It can be seen that the high-density ordered micro-pit array structure and the CuZn5 coating do not affect the electrochemical performance of the battery assembled by the Zn anode and the I / Mo2C@CN cathode pairing; Fig. 9The cycling performance and coulombic efficiency of the asymmetric battery assembled by the LT-Zn@CuZn5 electrode of the present invention and the I / Mo2C@CN cathode show that the battery assembled with the LT-Zn@CuZn5 electrode as the anode still maintains 89.5% of the original capacity after 15,000 cycles, proving that the joint introduction of the surface laser texturing technology and the CuZn5 coating obtained by alloying can significantly inhibit the Zn dendrite behavior and thus improve the cycling stability of the battery.

[0037] The above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention is described in detail with reference to the above preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present invention.

Claims

1. A method for preparing zinc foil for inhibiting zinc dendrite growth, characterized in that: The following steps are involved: The zinc foil is subjected to surface laser texturing treatment by a laser cutting machine to produce a high-density ordered micro-pit array structure on the surface of the zinc foil, thereby increasing the number of its surface active sites and eliminating scratches and pits produced by the zinc foil itself. The foil is then immersed in a CuCl2 solution for alloying treatment to produce a CuZn5 alloy layer, thereby obtaining the zinc foil for inhibiting the growth of zinc dendrites.

2. A method for preparing zinc foil for inhibiting zinc dendrite growth according to claim 1, characterized in that: The thickness of the zinc foil is 0.05 mm.

3. A method for preparing zinc foil for inhibiting zinc dendrite growth according to claim 1, characterized in that: The parameters of the laser cutting machine are speed of 1800 mm / s, current of 1 A, frequency of 170 kHz, pulse width of 1 μm, and the unit diameter of the high-density ordered micro-pit array structure finally produced is 10 μm and the depth is 4.5 μm.

4. A method for preparing zinc foil for inhibiting zinc dendrite growth according to claim 1, characterized in that: The concentration of the CuCl2 solution is 0.05 mol / L.

5. The method for preparing zinc foil for inhibiting zinc dendrite growth according to claim 1, characterized in that: The alloying treatment is to place the zinc foil with surface laser texture in a CuCl2 solution for 1 minute.

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