A negative electrode material for zinc-ion batteries, a preparation method thereof, and applications thereof

Abstract

The present invention relates to a negative electrode material for a zinc ion battery, a preparation method thereof, and an application thereof. The negative electrode material for the zinc ion battery is obtained by sequentially compounding a nickel-zinc alloy and a metallic nickel layer on the surface of a zinc sheet, and the composition of the nickel-zinc alloy is Ni2Zn 11 . Through constant voltage electrodeposition and a two-step annealing method, the present invention coats a nickel-zinc alloy layer on a zinc substrate. The nickel-zinc alloy layer and the zinc-based bottom layer are closely attached to form a nickel-zinc alloy-coated zinc substrate material. As a negative electrode material for a zinc ion battery, it has excellent electrochemical performance, high cycle stability, and long cycle life, and can solve problems such as dendrite growth, self-corrosion, and short cycle life of the negative electrode material for a zinc ion battery. At a current density of 0.5 mA cm ‑2 , the nickel-zinc alloy-coated zinc substrate material can operate stably for more than 1900 h, and the cycle life is significantly improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of material selection for electrode active substances, and particularly relates to a negative electrode material for a zinc-ion battery, a preparation method thereof, and an application thereof. Background Art

[0002] In rechargeable batteries, aqueous zinc-ion batteries have attracted much attention due to their simple operation, the use of water-based electrolytes, and the convenience of using zinc metal anodes. Zinc anodes have many excellent characteristics, including low cost, environmental friendliness, high theoretical capacity (up to 5854 mAh L -1 ), high abundance of zinc resources, low electrochemical potential (-0.76 V, relative to the standard hydrogen electrode), etc. However, due to the easy formation of by-products such as dendrites, zinc oxide, and zinc hydroxy sulfate during the charge-discharge cycle of the battery, the cycle life of the zinc anode is low. Therefore, it is particularly important to improve the zinc anode to increase the life of the zinc-ion battery. Generally, modification is carried out from two aspects. One is to design the anode structure, such as constructing a three-dimensional porous structure; the other is to protect the zinc anode through a protective layer, such as a metal coating or a polymer coating, etc.

[0003] Generally, the methods for designing the anode structure are often complex and difficult to operate, while the method of protecting the anode through a protective layer is more operable. Considering that the polymer coating generally has poor adhesion to the zinc anode, using a metal coating to protect the zinc anode is a very efficient strategy. Nickel-zinc alloy is an excellent corrosion-resistant coating, with characteristics such as low hydrogen embrittlement, high corrosion resistance, high stability, and machinability, so it has greater advantages than bare zinc and other zinc alloy coatings. At present, the technology for combining nickel-zinc alloy with the zinc anode is not yet perfect, the adhesion of the coating to the zinc anode is poor, and it is easy to fall off during the charge-discharge process of the battery. Therefore, it is urgent to find a new preparation method to combine nickel-zinc alloy with the zinc substrate to improve the performance of the negative electrode material for zinc-ion batteries. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a negative electrode material for a zinc-ion battery, a preparation method thereof, and an application thereof in view of the above deficiencies in the prior art. The negative electrode material for a zinc-ion battery is prepared by coating a zinc substrate material with a nickel-zinc alloy, and shows good electrochemical performance when used as a negative electrode material for a zinc-ion battery, solving problems such as dendrite growth, self-corrosion, and short cycle life in the negative electrode material for a zinc-ion battery.

[0005] To solve the above technical problems, the technical solution provided by the present invention is:

[0006] The first object of the present invention is to provide a negative electrode material for a zinc-ion battery. The negative electrode material for a zinc-ion battery is obtained by sequentially compounding a nickel-zinc alloy and a nickel metal layer on the surface of a zinc sheet. The composition of the nickel-zinc alloy is Ni2Zn11 。

[0007] According to the above solution, the total thickness of the nickel-zinc alloy and the nickel metal layer is 10-14 μm.

[0008] The second object of the present invention is to provide a method for preparing the above-mentioned anode material for a zinc-ion battery, and the specific steps are as follows:

[0009] 1) Polish the zinc sheet with sandpaper, then ultrasonically treat it in acetone, and finally clean it with isopropanol to obtain the treated zinc sheet;

[0010] 2) Add ammonium chloride and anhydrous nickel chloride to deionized water, and stir until completely dissolved to obtain an electrochemically deposited precursor solution;

[0011] 3) Use the zinc sheet treated in step 1) as the working electrode, a platinum electrode as the counter electrode, and a saturated calomel electrode as the reference electrode, place them in the electrochemically deposited precursor solution obtained in step 2), and perform electrochemically deposition using the three-electrode method to deposit a nickel layer on the surface of the zinc sheet to obtain a Ni@Zn composite material;

[0012] 4) Place the Ni@Zn composite material obtained in step 3) in a tubular furnace for annealing treatment to obtain a nickel-zinc alloy-coated zinc substrate material.

[0013] According to the above solution, the concentration of nickel chloride in the electrochemically deposited precursor solution in step 2) is 0.01-0.2 mol / L, and the molar ratio of ammonium chloride to anhydrous nickel chloride is 10:0.5-1.5.

[0014] According to the above solution, the electrochemically deposition process conditions in step 3) are: the working mode is a constant voltage electrochemically deposition mode, the deposition voltage is -1 to -1.3 V, and the deposition time is 300 to 3600 s.

[0015] According to the above solution, the annealing treatment process conditions in step 4) are: in a nitrogen atmosphere, first heat up at a heating rate of 0.5-5 °C / min to 130-200 °C and keep warm for 0.5-3 h, then heat up at a heating rate of 0.5-5 °C / min to 220-350 °C and keep warm for 0.5-3 h, and finally cool down to room temperature at a cooling rate of 0.5-5 °C / min.

[0016] The third object of the present invention is to provide the application of the above-mentioned anode material for a zinc-ion battery as an anode material for a zinc-ion battery.

[0017] The fourth object of the present invention is to provide a zinc-ion battery, including a positive electrode, an electrolyte, a separator, and a negative electrode, and the negative electrode includes the above-mentioned anode material for a zinc-ion battery.

[0018] Nickel-zinc alloy material Ni2Zn 11It has characteristics such as low hydrogen embrittlement, high corrosion resistance, high stability, and machinability, and has greater advantages than untreated bare zinc and other zinc alloy coatings. Combining this nickel-zinc alloy with a zinc substrate as the negative electrode material of a zinc-ion battery can effectively slow down the self-corrosion of the zinc negative electrode and the generation of by-products, thereby preventing the continuous consumption of the nickel-zinc alloy layer during the cycling process.

[0019] The beneficial effects of the present invention are as follows: 1. By means of constant voltage electrodeposition and two-step annealing, the nickel-zinc alloy layer is coated on the zinc substrate. The nickel-zinc alloy layer and the zinc substrate layer are closely bonded to form a nickel-zinc alloy-coated zinc substrate material. As the negative electrode material of a zinc-ion battery, it has excellent electrochemical performance, high cycle stability, and long cycle life, and can solve problems such as dendrite growth, self-corrosion, and short cycle life of the negative electrode material of a zinc-ion battery. At a current density of 0.5 mA cm -2 , the nickel-zinc alloy-coated zinc substrate material can operate stably for more than 1900 h, and the cycle life is significantly improved. 2. The preparation method of the present invention is simple in operation, short in process, and low in energy consumption, enabling the rapid mass production of the highly corrosion-resistant nickel-zinc alloy-coated zinc substrate material. Description of the Drawings

[0020] Figure 1 XRD patterns of the zinc sheet after the treatment in step 1) of Example 1 of the present invention, the Ni@Zn composite material obtained in step 5), and the nickel-zinc alloy-coated zinc substrate material obtained in step 6);

[0021] Figure 2 SEM images of the zinc sheet after the treatment in step 1) of Example 1, the Ni@Zn composite material obtained in step 5), and the nickel-zinc alloy-coated zinc substrate material obtained in step 6);

[0022] Figure 3 SEM image of the cross-section and cross-sectional element distribution map of the nickel-zinc alloy-coated zinc substrate material obtained in Example 1;

[0023] Figure 4 In-situ optical microscope images during the charging test of the nickel-zinc alloy-coated zinc substrate material obtained in step 6) of Example 1 and the zinc sheet after the treatment in step 1);

[0024] Figure 5 Linear polarization curves of the nickel-zinc alloy-coated zinc substrate material obtained in step 6) of Example 1 and the zinc sheet after the treatment in step 1) tested under a chemical workstation;

[0025] Figure 6 Voltage-time graphs of symmetric batteries assembled respectively with the nickel-zinc alloy-coated zinc substrate material obtained in step 6) of Example 1 and the zinc sheet after the treatment in step 1) tested;

[0026] Figure 7XRD patterns of the two materials after 50 cycles at 0.5 mA cm -1 and 0.5 mAh cm -2 for the symmetric cells assembled with the nickel-zinc alloy-coated zinc substrate material obtained in step 6) of Example 1 and the zinc sheet treated in step 1);

[0027] Figure 8 SEM images of the two materials after 50 cycles at 0.5 mA cm -1 and 0.5 mAh cm -2 for the symmetric cells assembled with the nickel-zinc alloy-coated zinc substrate material obtained in step 6) of Example 1 and the zinc sheet treated in step 1);

[0028] Figure 9 Long cycle test chart of the full cell assembled with the nickel-zinc alloy-coated zinc substrate material obtained in step 6) of this example or the zinc sheet treated in step 1) as the negative electrode material and manganese dioxide as the positive electrode material. Detailed implementation mode

[0029] The principles and features of the present invention will be described below in conjunction with specific implementation modes. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention. Unless otherwise defined, all technical and scientific terms used herein shall have the meanings commonly understood by those skilled in the technical field of the present invention.

[0030] The present invention provides a negative electrode material for a zinc-ion battery, and its preparation method includes the following steps:

[0031] 1) Sand the zinc sheet, then ultrasonically treat it in acetone, and finally clean it with isopropanol to obtain the treated zinc sheet;

[0032] 2) Add ammonium chloride and anhydrous nickel chloride to deionized water and stir until completely dissolved to obtain an electrochemical deposition precursor solution;

[0033] 3) Use the zinc sheet treated in step 1) as the working electrode, a platinum electrode as the counter electrode, and a saturated calomel electrode as the reference electrode, place them in the electrochemical deposition precursor solution obtained in step 2), and perform electrochemical deposition using the three-electrode method to deposit a nickel layer on the surface of the zinc sheet to obtain a Ni@Zn composite material;

[0034] 4) Anneal the Ni@Zn composite material obtained in step 3) in a tube furnace to obtain a nickel-zinc alloy-coated zinc substrate material.

[0035] In this embodiment, nickel-zinc alloy is coated on the zinc substrate through constant-voltage electrodeposition and two-step annealing. The nickel-zinc alloy layer and the zinc substrate are closely attached to form a nickel-zinc alloy-coated zinc substrate material, which has excellent electrochemical performance, high cycle stability and long cycle life as the negative electrode material of a zinc-ion battery, and can solve problems such as dendrite growth, self-corrosion and short cycle life of the negative electrode material of a zinc-ion battery. At a current density of 0.5 mA cm -2 , the nickel-zinc alloy-coated zinc substrate material can operate stably for more than 1900 h, and the cycle life is significantly improved.

[0036] During the above constant-voltage electrochemical deposition process, the voltage of the electrochemical deposition is in the range of -1 V to -1.3 V, preferably -1.2 V, and the first duration is in the range of 300 s to 3600 s, preferably 600 s.

[0037] Further, the two-step temperature-raising annealing treatment of the Ni@Zn composite material in a tube furnace to obtain the nickel-zinc alloy-coated zinc substrate material includes: putting the Ni@Zn composite material into a tube furnace, heating it for the first duration, then heating it for the second duration, and obtaining the nickel-zinc alloy-coated zinc substrate material after cooling.

[0038] Specifically, the heating temperature of the first duration is in the range of 130 °C to 200 °C, preferably 140 °C, the heating rate is in the range of 0.5 °C / min to 5 °C / min, preferably 1 °C / min, and the heating time is in the range of 0.5 h to 3 h, preferably 1 h; the heating temperature of the second duration is in the range of 220 °C to 350 °C, preferably 240 °C, the heating rate is in the range of 0.5 °C / min to 5 °C / min, preferably 1 °C / min, and the heating time is in the range of 0.5 h to 3 h, preferably 1 h; the entire annealing process is carried out in an N2 (50 sccm) gas flow at atmospheric pressure (760 Torr), and the cooling rate during the final cooling is in the range of 0.5 °C / min to 5 °C / min, preferably 1 °C / min.

[0039] Based on the above embodiments, the present invention gives the following specific embodiments of the negative electrode material of a zinc-ion battery and its preparation method.

[0040] Example 1

[0041] A negative electrode material of a zinc-ion battery, and its preparation method includes the following steps:

[0042] 1) Take a zinc sheet with an area of 1 cm × 2 cm (thickness of 0.2 mm), polish it with 2000-mesh sandpaper, then ultrasonically treat it in acetone for 30 min, and finally wash it three times with isopropanol to remove surface contamination, obtaining a treated zinc sheet;

[0043] 2) Weigh 2.675 g of ammonium chloride and 0.648 g of anhydrous nickel chloride, add them to 50 mL of deionized water, and stir at room temperature for 3 h until completely dissolved to obtain an electrochemical deposition precursor solution;

[0044] 3) Build an electrochemical deposition platform using the three - electrode method. Use the zinc sheet treated in step 1) above as the working electrode, a platinum electrode as the counter electrode, and a saturated calomel electrode as the reference electrode. Immerse the three electrodes into the electrochemical deposition precursor solution obtained in step 2) to the same depth;

[0045] 4) Turn on the electrochemical workstation, set the working mode to the constant - voltage electrochemical deposition mode, set the voltage to - 1.2 V, and the deposition time to 600 s. Start the electrochemical workstation. After the electrochemical workstation stops working, take out the working electrode and wash it three times with deionized water and ethanol respectively;

[0046] 5) Wrap the washed working electrode with filter paper and place it in a ventilated place to dry naturally to obtain the Ni@Zn composite material;

[0047] 6) Put the above - mentioned Ni@Zn composite material into a tubular furnace, introduce N2, set the program for annealing treatment. First, heat it at a heating rate of 1 °C / min to 140 °C and hold for 1 h, then heat it at a heating rate of 1 °C / min to 240 °C and hold for 1 h, and finally cool it at a cooling rate of 1 °C / min. After the temperature drops to room temperature, take it out. The obtained sample is the nickel - zinc alloy - coated zinc substrate material.

[0048] The X - ray diffraction (XRD) patterns of the zinc sheet (B - Zn) treated in step 1) of this example, the Ni@Zn composite material (Ni@Zn) obtained in step 5), and the nickel - zinc alloy - coated zinc substrate material (Ni - Zn alloy) obtained in step 6) are as Figure 1 shown. The patterns indicate that the Ni@Zn composite material can detect the peaks of nickel, corresponding to PDF#87 - 0712; the nickel - zinc alloy - coated zinc substrate material can detect the peaks of the nickel - zinc alloy, corresponding to PDF#03 - 065 - 5310. After analysis, the alloy phase is Ni2Zn 11 , indicating that a nickel layer is successfully plated on the zinc substrate after constant - voltage electrochemical deposition, and after two - step annealing treatment, part of the nickel layer combines with the zinc substrate to successfully form a nickel - zinc alloy. From the XRD curve of the nickel - zinc alloy - coated zinc substrate material, the peaks of Zn, Ni, and Ni2Zn 11 can be observed, indicating that the final sample contains three components: Zn, Ni2Zn 11 and Ni. That is, the so - called Ni - Zn alloy has a sandwich structure of Zn layer, Ni2Zn 11 layer, and Ni layer.

[0049] The surface morphologies of the zinc sheet (bare zinc) after the treatment in step 1) of this embodiment, the Ni@Zn composite material obtained in step 5), and the nickel-zinc alloy-coated zinc substrate material obtained in step 6) are as follows Figure 2 shown. Compared with the smooth surface of the bare zinc, the Ni@Zn composite material obtained by constant-voltage electrochemical deposition has a locally uniform distribution on the surface, but there are fine stripe-like grooves. After further two-step heating and annealing treatment, the prismatic particles on the surface of the nickel-zinc alloy-coated zinc substrate material are finer and more uniformly distributed. From the cross-sectional view of the nickel-zinc alloy-coated zinc substrate material ( Figure 3 left), it can be clearly observed that the overall thickness of the coating is about 12 μm, and it is tightly connected to the zinc base layer, indicating that the binding property between the coating and the zinc substrate is very excellent. However, because the nickel-zinc alloy layer is closely connected to the zinc layer and the nickel layer, the boundary line is not obvious enough, so only the overall thickness of the coating can be observed by SEM. Figure 3 The left and right are respectively the element distribution maps of the cross-sectional view of the nickel-zinc alloy-coated zinc substrate material, and it can be more clearly seen that the thickness of the coating is about 12 μm.

[0050] The nickel-zinc alloy-coated zinc substrate material prepared by the present invention can be used as the negative electrode material of a zinc-ion battery. For the performance test of a symmetric battery, 2M ZnSO4 solution is selected as the electrolyte, GF / A glass fiber is used as the separator, and a CR2016-type battery case is assembled into a button battery.

[0051] The nickel-zinc alloy-coated zinc substrate material obtained in step 6) of this embodiment or the zinc sheet after the treatment in step 1) is assembled through an in-situ mold, and then a charging test is carried out at a current density of 10 mA cm -2 for 20 min under a chemical workstation, and real-time observation is carried out through an optical microscope. The in-situ optical microscope images of the two materials at different time periods are as follows Figure 4 shown. It can be observed from the in-situ optical microscope that the corrosion of the bare zinc can be observed at 4 min, and the corrosion phenomenon of the bare zinc negative electrode is significantly aggravated after 20 min of reaction. In contrast, no corrosion phenomenon is observed for the nickel-zinc alloy-coated zinc substrate material even after 20 min, indicating that the nickel-zinc alloy-coated zinc substrate material can control the generation of by-products, reduce the corrosion phenomenon, and has high corrosion resistance. After 20 min, it can also be seen that the growth of zinc dendrites on the nickel-zinc alloy-coated zinc substrate material is more uniform than that of the bare zinc.

[0052] Similarly, under a chemical workstation, a linear polarization corrosion test is carried out in 2M ZnSO4 electrolyte using a three-electrode system. The nickel-zinc alloy-coated zinc substrate material obtained in step 6) of this embodiment or the zinc sheet after the treatment in step 1) is used as the working electrode, a foil is used as the counter electrode, and a saturated calomel electrode is used as the reference electrode. The obtained linear polarization corrosion curve is as follows Figure 5As shown, it indicates that the nickel-zinc alloy-coated zinc substrate material can significantly reduce the corrosion current, thereby slowing down the corrosion rate. The above test results show that the nickel-zinc alloy-coated zinc substrate material can slow down the corrosion of the zinc negative electrode.

[0053] Symmetric cells were assembled using the nickel-zinc alloy-coated zinc substrate material obtained in step 6) of this example or the zinc sheet treated in step 1), and the long-term cycling stability of the two materials was tested by observing the plating / stripping behavior of zinc in the symmetric cells. Here, 2016-type button cells were selected for assembly. The voltage-time diagrams of the two symmetric cells are as Figure 6 shown. The test results show that at a current density of 0.5 mA cm -2 and a capacity of 0.5 mAh cm -2 , although the initial polarization difference between the nickel-zinc alloy-coated zinc substrate material and bare zinc is not obvious, about 38 mV, the symmetric cell prepared with the nickel-zinc alloy-coated zinc substrate material shows excellent cycling stability and can operate stably for more than 1900 h, with a significant improvement in the cycle life. More surprisingly, the polarization voltage of the symmetric cell prepared with the nickel-zinc alloy-coated zinc substrate material drops to 24 mV after 1900 hours. The inset shows the detailed voltage curve, indicating that the polarization tends to decrease with the increase in the number of cycles.

[0054] Figure 7 XRD patterns of the two materials after 50 cycles for the symmetric cells assembled using the nickel-zinc alloy-coated zinc substrate material obtained in step 6) of this example or the zinc sheet treated in step 1) at 0.5 mA cm -1 and 0.5 mAh cm -2 . In the XRD pattern of bare zinc after 50 cycles, the peaks of the zinc hydroxy sulfate by-product can be clearly observed, while the peaks of the by-product are not obvious for the nickel-zinc alloy-coated zinc substrate material, indicating that the nickel-zinc alloy-coated zinc substrate material can well protect the zinc negative electrode and reduce the generation of by-products.

[0055] Figure 8 SEM images of the two materials after 50 cycles for the symmetric cells assembled using the nickel-zinc alloy-coated zinc substrate material obtained in step 6) of this example or the zinc sheet treated in step 1) at 0.5 mA cm -1 and 0.5 mAh cm -2 . It can be seen from the figure that at the same magnification, the nucleation size of zinc on the surface of bare zinc is significantly larger than that of the nickel-zinc alloy-coated zinc substrate material, indicating that the nickel-zinc alloy-coated zinc substrate material can well control the nucleation and growth of zinc and slow down the formation of zinc dendrites.

[0056] Figure 9Long cycle test chart of a full cell assembled with the nickel-zinc alloy-coated zinc substrate material obtained in step 6) of this embodiment or the zinc sheet treated in step 1) as the negative electrode material and manganese dioxide as the positive electrode material. The full cell with the nickel-zinc alloy-coated zinc substrate material can stably operate for 1000 cycles at a current density of 1 A g -1 The discharge capacity increases from the initial 101 mAh g -1 to 154 mAh g -1 at the 20th cycle and finally remains at 123 mAh g -1 in the 1000th cycle, with a capacity retention rate of 79.8%. For the full cell with bare zinc, the capacity decreases from the initial 140 mAh g -1 to 76 mAh g -1 after 1000 cycles, and the capacity retention rate is only 54.2%.

[0057] Example 2

[0058] A negative electrode material for a zinc-ion battery, and its preparation method includes the following steps:

[0059] 1) Take a zinc sheet with an area of 1 cm × 2 cm, polish it with 2000-mesh sandpaper, then ultrasonically treat it in acetone for 0.5 h, and finally wash it three times with isopropanol to remove surface contamination, obtaining the treated zinc sheet;

[0060] 2) Weigh 2.675 g of ammonium chloride and 0.648 g of anhydrous nickel chloride, add them to 50 mL of deionized water, and stir at room temperature for 3 h until completely dissolved to obtain an electrochemical deposition precursor solution;

[0061] 3) Build an electrochemical deposition platform using the three-electrode method. Use the zinc sheet treated in step 1) above as the working electrode, a platinum electrode as the counter electrode, and a saturated calomel electrode as the reference electrode. Immerse the three electrodes into the electrochemical deposition precursor solution obtained in step 2) to the same depth;

[0062] 4) Turn on the electrochemical workstation, set the working mode to the constant voltage electrochemical deposition mode, set the voltage to -1.2 V, and the deposition time to 1800 s. Then start the electrochemical workstation. After the electrochemical workstation stops working, take out the working electrode and wash it three times with deionized water and ethanol respectively;

[0063] 5) Wrap the washed working electrode with filter paper and place it in a ventilated place to dry naturally to obtain the Ni@Zn composite material;

[0064] 6) Place the above Ni@Zn composite material into a tube furnace, introduce N2, set the program, first heat it at a heating rate of 1 °C / min to 150 °C, hold for 1 h, then heat it at a heating rate of 2 °C / min to 270 °C, hold for 1 h, and finally cool it at a cooling rate of 1 °C / min. After the temperature drops to room temperature, take it out. The obtained sample is the nickel-zinc alloy-coated zinc substrate material.

[0065] Both the positive and negative electrode materials use the nickel-zinc alloy-coated zinc substrate material obtained in this example to assemble a symmetric battery. At a current density of 0.5 mA cm -1 , the cycle can operate stably for more than 1200 h.

[0066] Example 3

[0067] A negative electrode material for a zinc-ion battery, and its preparation method includes the following steps:

[0068] 1) Take a zinc sheet with an area of 1 cm × 2 cm, polish it with 2000-mesh sandpaper, then ultrasonically treat it in acetone for 0.5 h, and finally wash it three times with isopropanol to remove surface contamination to obtain the treated zinc sheet;

[0069] 2) Weigh 2.675 g of ammonium chloride and 0.648 g of anhydrous nickel chloride, add them to 50 mL of deionized water, and stir at room temperature for 3 h until completely dissolved to obtain an electrochemical deposition precursor solution;

[0070] 3) Build an electrochemical deposition platform using the three-electrode method. Use the zinc sheet treated in step 1) above as the working electrode, a platinum electrode as the counter electrode, and a saturated calomel electrode as the reference electrode. Immerse the three electrodes into the electrochemical deposition precursor solution obtained in step 2) to the same depth;

[0071] 4) Turn on the electrochemical workstation, set the working mode to the constant voltage electrochemical deposition mode, set the voltage to -1.1 V, and the deposition time to 3600 s. Then start the electrochemical workstation. After the electrochemical workstation stops working, take out the working electrode and wash it three times with deionized water and ethanol respectively;

[0072] 5) Wrap the washed working electrode with filter paper and place it in a ventilated place to dry naturally to obtain the Ni@Zn composite material;

[0073] 6) Place the above Ni@Zn composite material into a tube furnace, introduce N2, set the program, first heat it at a heating rate of 2 °C / min to 130 °C, hold for 1 h, then heat it at a heating rate of 1 °C / min to 300 °C, hold for 1 h, and finally cool it at a cooling rate of 2 °C / min. After the temperature drops to room temperature, take it out. The obtained sample is the nickel-zinc alloy-coated zinc substrate material.

[0074] Both the positive and negative electrode materials use the nickel-zinc alloy-coated zinc substrate material obtained in this example to assemble a symmetric battery. At a current density of 0.5 mA cm -1 , the cycle can operate stably for more than 800 h.

[0075] Example 4

[0076] A negative electrode material for a zinc-ion battery, and its preparation method includes the following steps:

[0077] 1) Take a zinc sheet with an area of 1 cm × 2 cm, polish it with 2000-mesh sandpaper, then ultrasonically treat it in acetone for 0.5 h, and finally wash it three times with isopropanol to remove surface contamination, obtaining the treated zinc sheet;

[0078] 2) Weigh 2.675 g of ammonium chloride and 0.648 g of anhydrous nickel chloride, add them to 50 mL of deionized water, and stir at room temperature for 3 h until completely dissolved to obtain an electrochemical deposition precursor solution;

[0079] 3) Build an electrochemical deposition platform using the three-electrode method. Use the zinc sheet treated in step 1) above as the working electrode, a platinum electrode as the counter electrode, and a saturated calomel electrode as the reference electrode. Immerse the three electrodes into the electrochemical deposition precursor solution obtained in step 2) to the same depth;

[0080] 4) Turn on the electrochemical workstation, set the working mode to the constant voltage electrochemical deposition mode, set the voltage to -1.3 V, and the deposition time to 600 s. Then start the electrochemical workstation. After the electrochemical workstation stops working, take out the working electrode and wash it three times with deionized water and ethanol respectively;

[0081] 5) Wrap the washed working electrode with filter paper and place it in a ventilated place to dry naturally to obtain the Ni@Zn composite material;

[0082] 6) Put the above Ni@Zn composite material into a tube furnace, introduce N2, set the program, first heat it to 140 °C at a heating rate of 2 °C / min, hold for 1 h, then heat it to 250 °C at a heating rate of 2 °C / min, hold for 1 h, and finally cool it at a cooling rate of 1 °C / min. After the temperature drops to room temperature, take it out. The obtained sample is the nickel-zinc alloy-coated zinc substrate material.

[0083] Both the positive and negative electrode materials use the nickel-zinc alloy-coated zinc substrate material obtained in this example to assemble a symmetric battery. At a current density of 0.5 mA cm -1 , the cycle can operate stably for nearly 900 h.

[0084] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

Claims

1. A negative electrode material for a zinc-ion battery, characterized in that, The negative electrode material of the zinc-ion battery is obtained by sequentially compounding a nickel-zinc alloy and a nickel metal layer on the surface of a zinc sheet, and the composition of the nickel-zinc alloy is Ni2Zn 11 .

2. The negative electrode material for a zinc ion battery according to claim 1, characterized in that, The total thickness of the nickel-zinc alloy and the nickel metal layer is 10 to 14 μm.

3. A method for preparing the anode material of the zinc ion battery according to claim 1 or 2, characterized in that, The specific steps are as follows: 1) Polish the zinc sheet with sandpaper, then perform ultrasonic treatment in acetone, and finally clean it with isopropanol to obtain the treated zinc sheet; 2) Add ammonium chloride and anhydrous nickel chloride to deionized water and stir until completely dissolved to obtain an electrochemical deposition precursor solution; 3) Use the zinc sheet treated in step 1) as the working electrode, a platinum electrode as the counter electrode, and a saturated calomel electrode as the reference electrode, place them in the electrochemical deposition precursor solution obtained in step 2), and perform electrochemical deposition using the three-electrode method to deposit a nickel layer on the surface of the zinc sheet to obtain a Ni@Zn composite material; 4) Place the Ni@Zn composite material obtained in step 3) in a tube furnace for annealing treatment to obtain a nickel-zinc alloy-coated zinc substrate material.

4. The preparation method of the negative electrode material for a zinc ion battery according to claim 3, wherein, In the electrochemical deposition precursor solution described in step 2), the concentration of nickel chloride is 0.01 to 0.2 mol / L, and the molar ratio of ammonium chloride to anhydrous nickel chloride is 10:0.5 to 1.

5.

5. The preparation method of the negative electrode material for a zinc ion battery according to claim 3, characterized in that, The electrochemical deposition process conditions described in step 3) are: the working mode is a constant voltage electrochemical deposition mode, the deposition voltage is -1 to -1.3 V, and the deposition time is 300 to 3600 s.

6. The preparation method of the anode material for a zinc-ion battery according to claim 3, characterized in that, The annealing treatment process conditions described in step 4) are: in a nitrogen atmosphere, first heat up at a heating rate of 0.5 to 5 °C / min to 130 to 200 °C and hold for 0.5 to 3 h, then heat up at a heating rate of 0.5 to 5 °C / min to 220 to 350 °C and hold for 0.5 to 3 h, and finally cool down to room temperature at a cooling rate of 0.5 to 5 °C / min.

7. Use of the zinc ion battery negative electrode material according to claim 1 or 2 as a zinc ion battery negative electrode material.

8. A zinc-ion battery, characterized in that, It includes a positive electrode, an electrolyte, a separator, and a negative electrode, and the negative electrode includes the zinc ion battery negative electrode material according to claim 1 or 2.

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