Preparation method of aqueous zinc ion battery negative electrode

Abstract

The invention discloses a preparation method of an aqueous zinc ion battery negative electrode, and belongs to the technical field of aqueous zinc ion batteries, and the preparation method comprises the following steps: (1) preparing a hydrochloric acid solution; (2) slowly adding lithium fluoride into a hydrochloric acid solution, stirring until the lithium fluoride is completely dissolved, and gradually adding Ti3AlC2 into the solution; (3) carrying out etching reaction on the mixed solution to obtain an MXene dispersion, and washing the MXene dispersion to obtain an MXene material; (4) tinning the zinc powder to obtain tinned zinc powder ZnSn; (5) washing ZnSn, and storing for later use; (6) weighing ZnSn, an MXene material and NFC according to a mass ratio of 7: 2: 1 to prepare a dispersion liquid; and (7) carrying out vacuum filtration on the dispersion liquid by using a filter membrane, taking out the filtered film, drying and compacting to obtain the ZnSn-coated MXene-NFC film material which is used as the battery negative electrode material. The water-based zinc ion battery prepared by the method can solve the problem that the electrochemical performance of the existing water-based zinc ion battery is poor due to disordered growth of negative electrode zinc dendrites.

Description

Technical Field

[0001] The present invention belongs to the technical field of aqueous zinc-ion batteries, and particularly relates to a method for preparing a negative electrode of an aqueous zinc-ion battery. Background Art

[0002] With the rapid development of the global economy and the continuous growth of the population, energy consumption has increased sharply. The overuse of traditional fossil fuels not only faces the crisis of depletion but also causes serious environmental problems, such as climate change caused by greenhouse gas emissions. In this context, the development of sustainable, clean, and efficient new energy storage technologies has become the focus of common concern in the scientific community and the industrial community. Zinc, as a metal element rich in the earth's crust, is abundant in resources and low in price. Aqueous zinc-ion batteries store and release energy based on the redox reaction of zinc, and they have characteristics such as high theoretical specific capacity and appropriate redox potential. Moreover, aqueous zinc-ion batteries can avoid using expensive and environmentally harmful organic electrolytes during the manufacturing process, which gives them significant cost advantages and environmental advantages in large-scale energy storage applications.

[0003] The disordered growth of zinc dendrites on the negative electrode of traditional aqueous zinc-ion batteries is one of the main problems faced by zinc-ion batteries. It can lead to unstable electrode surface morphology, cause non-uniformity of electrochemical reactions, and ultimately affect the cycle life and electrochemical performance of the battery. The formation of dendrites is often accompanied by side reactions such as hydrogen evolution and the generation of inert by-products, which not only significantly reduces the reversible capacity of the battery but also may cause safety problems such as short circuits. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for preparing a negative electrode of an aqueous zinc-ion battery to solve the problem of poor electrochemical performance caused by the disordered growth of zinc dendrites on the negative electrode of existing aqueous zinc-ion batteries.

[0005] The technical solution adopted by the present invention is as follows:

[0006] A method for preparing a negative electrode of an aqueous zinc-ion battery, comprising the following steps:

[0007] (1) Accurately measure 15 mL of concentrated hydrochloric acid with a measuring cylinder and mix it with 5 mL of deionized water to prepare 20 mL of a 9 mol / L -1 hydrochloric acid solution;

[0008] (2) Slowly add 1.6 g of lithium fluoride to the hydrochloric acid solution prepared in step (1), stir until completely dissolved, and then gradually add 1 g of Ti3AlC2 to the solution;

[0009] (3) Seal the container containing the mixed solution in step (2), and carry out an etching reaction under the conditions of 40 °C and 550 rpm. After the etching is completed, an MXene dispersion is obtained, and the MXene dispersion is washed with deionized water to finally obtain an MXene material;

[0010] (4) Prepare a mixed solution containing 10 g L -1 of SnCl2·H2O, 70 g L - 1 of NaH2PO2·H2O, 770 g L -1 of CS(NH2)2 and 2 g L -1 of HCl. Place zinc powder in this mixed solution, take it out after reacting for 5 minutes to complete the tin plating of the zinc powder, and obtain the tin-plated zinc powder Zn|Sn;

[0011] (5) Thoroughly wash Zn|Sn with deionized water, and then store Zn|Sn in a vacuum oven for standby;

[0012] (6) Weigh 350 mg of Zn|Sn, 100 mg of MXene material and 50 mg of NFC according to a mass ratio of 7:2:1, add them to a beaker, and add 60 mL of deionized water, and stir well to ensure uniform dispersion to form a dispersion;

[0013] (7) Use a filter membrane with a diameter of 40 μm and a pore size of 0.22 μm to carry out vacuum filtration on the dispersion obtained in step (6), take out the filtered thin film, carry out freeze-drying, and compact it under a pressure of 10 MPa to obtain a Zn|Sn@MXene-NFC thin film material as the negative electrode material of the battery.

[0014] Further, the stirring time is not less than 20 minutes.

[0015] Further, the etching reaction duration is 30 hours.

[0016] In summary, due to the adoption of the above technical solutions, the beneficial effects of the present invention are:

[0017] 1. In the present invention, a simple and low-cost method is adopted to prepare a Zn|Sn@MXene-NFC thin film as the negative electrode material of an aqueous zinc-ion battery, which can effectively inhibit the generation of zinc dendrites and inert products on the negative electrode, ensure that the battery achieves high cycle stability, and has excellent electrochemical performance.

[0018] 2. In the present invention, the MXene material has a large interlayer spacing and adjustable surface functional groups, providing favorable channels and active sites for the insertion and extraction of zinc ions. At the same time, it has excellent metallic conductivity, which can effectively reduce the resistance of the electrode material and promote the rapid transmission of electrons inside the electrode. Tin, as a coating material, its excellent electrochemical properties enable it to effectively guide the uniform deposition of zinc, improve the mechanical and electrochemical properties of the electrode, and enhance the overall performance of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] To more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for the embodiments. It should be understood that the following drawings only show some embodiments of the present invention, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other relevant drawings can also be obtained based on these drawings, where:

[0020] Figure 1 is the rate performance graph of the aqueous zinc-ion battery with the present invention as the negative electrode;

[0021] Figure 2 is the cycle performance graph of the aqueous zinc-ion battery with the present invention as the negative electrode. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Usually, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0023] Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents the selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0024] Combined with the specification appendix Figure 1-2 ,

[0025] A method for preparing a negative electrode of an aqueous zinc-ion battery includes the following steps:

[0026] (1) Accurately measure 15 mL of concentrated hydrochloric acid with a measuring cylinder and mix it with 5 mL of deionized water to prepare 20 mL of 9 mol L -1 hydrochloric acid solution;

[0027] (2) Slowly add 1.6 g of lithium fluoride to the hydrochloric acid solution prepared in step (2.1), stir for 20 minutes until completely dissolved, and then gradually add 1 g of Ti3AlC2 to the solution;

[0028] (3) Seal the container containing the mixed solution in step (2.2), and carry out an etching reaction at 40 °C and 550 rpm. The etching reaction duration is 30 hours. After the etching is completed, an MXene dispersion is obtained, and the MXene dispersion is washed with deionized water to finally obtain an MXene material;

[0029] (4) Prepare a mixed solution containing 10 g L -1 of SnCl2·H2O, 70 g L - 1 of NaH2PO2·H2O, 770 g L -1 of CS(NH2)2 and 2 g L -1 of HCl. Place zinc powder in this mixed solution, take it out after reacting for 5 minutes to complete the tin plating of zinc powder, and obtain tin-plated zinc powder Zn|Sn;

[0030] (5) Thoroughly wash Zn|Sn with deionized water, and then store Zn|Sn in a vacuum oven for standby;

[0031] (6) Weigh 350 mg of Zn|Sn, 100 mg of MXene material, and 50 mg of NFC according to a mass ratio of 7:2:1, add them to a beaker, and add 60 mL of deionized water, and stir well to ensure uniform dispersion to form a dispersion;

[0032] (7) Use a filter membrane with a diameter of 40 μm and a pore size of 0.22 μm to carry out vacuum filtration on the dispersion obtained in step (6), take out the filtered thin film, carry out freeze-drying, and compact it under a pressure of 10 MPa to obtain a Zn|Sn@MXene-NFC thin film material as the battery anode material.

[0033] In this example, the aqueous zinc-ion battery with the Zn|Sn@MXene-NFC thin film as the anode material has excellent electrochemical performance. The Zn|Sn@MXene-NFC thin film can effectively inhibit the generation of zinc dendrites and inert products on the anode, effectively improve the conductivity and structural stability of the electrode, and significantly improve the rate performance and cycle stability of the battery. The aqueous zinc-ion battery with the Zn|Sn@MXene-NFC thin film as the anode is tested in the voltage range of 1.0 - 1.85 V. The rate performance of the obtained zinc-ion battery is as Figure 1 shown. At the initial 0.2 Ag -1 current density, the discharge specific capacity at the 10th cycle is 212.3 Ag -1When the current density is successively increased to 0.5, 1.0, 2.0, and 3.0 Ag -1 , the discharge specific capacities at the last cycle at each rate are 171.5 mAh g -1 , 158.2 mAh g - 1, 122.8 mAh g -1 , and 100.3 mAh g -1 . When the current density is restored to 0.2 mA cm -2 , the specific capacity can be restored again. The aqueous zinc-ion battery with Zn|Sn@MXene-NFC film as the anode has a cycling performance at a current density of 1 Ag -1 as shown in Figure 2 . After 1000 charge / discharge cycles, the reversible specific capacity of this zinc-ion battery is 111.2 mAh g -1 .

[0034] Among them, NFC represents nanocellulose.

[0035] The above is the embodiment of the present invention. The foregoing are the various preferred embodiments of the present invention. If the preferred implementation manners in each preferred embodiment are not obviously self-contradictory or premised on a certain preferred implementation manner, the preferred implementation manners can be arbitrarily superimposed and combined. The embodiments and the specific parameters in the embodiments are only for clearly expressing the verification process of the invention, and are not used to limit the patent protection scope of the present invention. The patent protection scope of the present invention still depends on its claims. All equivalent structural changes made by using the content of the specification and drawings of the present invention should, by the same token, be included in the protection scope of the present invention.

Claims

1. A preparation method of a negative electrode for an aqueous zinc-ion battery, characterized in that, It includes the following steps: (1) Accurately measure 15 mL of concentrated hydrochloric acid with a graduated cylinder and mix it with 5 mL of deionized water to prepare 20 mL of a hydrochloric acid solution with a concentration of 9 mol / L. -1 solution. (2) Slowly add 1.6 g of lithium fluoride to the hydrochloric acid solution prepared in step (1), stir until completely dissolved, and then gradually add 1 g of Ti3AlC2 to the solution; (3) Seal the container containing the mixed solution in step (2), and carry out an etching reaction under the conditions of 40 °C and 550 rpm. After the etching is completed, an MXene dispersion is obtained, and the MXene dispersion is washed with deionized water to finally obtain an MXene material; (4) Prepare a mixed solution, the mixed solution contains 10 g / L -1 of SnCl2·H2O, 70 g / L - of NaH2PO2·H2O, 770 g / L -1 of CS(NH2)2 and 2 g / L -1 of HCl. Place the zinc powder in this mixed solution, take it out after reacting for 5 minutes to complete the tin plating on the zinc powder and obtain the tinned zinc powder Zn|Sn; (5) Thoroughly wash Zn|Sn with deionized water, and then store Zn|Sn in a vacuum oven for standby; (6) Weigh 350 mg of Zn|Sn, 100 mg of the MXene material, and 50 mg of NFC according to a mass ratio of 7:2:1, add them to a beaker, and add 60 mL of deionized water, and stir well to ensure uniform dispersion to form a dispersion; (7) Use a filter membrane with a diameter of 40 μm and a pore size of 0.22 μm to vacuum filter the dispersion obtained in step (6), take out the filtered film, perform freeze-drying, and compact it under a pressure of 10 MPa to obtain a Zn|Sn@MXene-NFC thin film material as the battery anode material.

2. The preparation method of a negative electrode of an aqueous zinc ion battery according to claim 1, characterized in that, In step (2), the stirring time is not less than 20 minutes.

3. The preparation method of a negative electrode of an aqueous zinc ion battery according to claim 1, characterized in that In step (3), the etching reaction duration is 30 hours.

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