CN116314579B - A preparation method of a modified zinc negative electrode modified by a multifunctional interface layer - Google Patents

Abstract

The invention provides a preparation method of a multifunctional interface layer modified zinc negative electrode, which utilizes an in-situ displacement reaction to generate a multifunctional ZnSe-Ag interface layer on the surface of the zinc negative electrode, on one hand, the ZnSe-Ag interface layer can reduce the nucleation overpotential of zinc ions, guide the uniform deposition of the zinc ions, effectively inhibit the growth of dendrites, greatly improve the service life and the cycle performance of a battery, and on the other hand, the ZnSe-Ag interface layer is used as a physical barrier to block the contact of the zinc negative electrode and water molecules, effectively solve the technical problems of side reactions such as hydrogen evolution, corrosion and the like of the zinc negative electrode of a water-based zinc ion battery, avoid the passivation of the surface of the negative electrode and the consumption of active zinc, prolong the service life of the battery, promote the practical process of the water-based zinc ion battery with high specific energy and stable cycle, and have simple operation and simple reaction conditions and can realize large-scale application.

Description

A preparation method of a modified zinc negative electrode modified by a multifunctional interface layer

technical field

The invention relates to the technical field of electrode materials, in particular to a preparation method of a modified zinc negative electrode modified by a multifunctional interface layer.

Background technique

With the increasing seriousness of the global energy crisis and environmental pollution, people urgently need sustainable renewable green and clean energy. Electrochemical energy storage technology, that is, battery, has attracted more and more attention because of its advantages of convenient use, less environmental pollution, and high conversion efficiency. At present, lithium-ion batteries occupy a dominant position in the energy storage market, but the organic electrolyte system used in them has safety hazards such as toxicity and flammability, and the low abundance and high cost of metal lithium resources have seriously hindered its large-scale application. In response to this problem, researchers have proposed to replace organic electrolytes with safer aqueous electrolytes to develop new aqueous metal-ion batteries. Among many metals, zinc is abundant in nature, low in price, and high in energy density (820 mAh·g ^-1 , 5855 mAh·cm ^-3 ), which has broad application prospects. Based on the above perspectives, the aqueous zinc-ion battery is a new energy storage system with great development prospects.

However, metallic zinc is thermodynamically unstable in aqueous solution, and side reactions such as hydrogen evolution and corrosion inevitably exist when it is directly used as the anode material of aqueous batteries, resulting in surface passivation and consumption of active zinc. At the same time, due to the "tip effect" in the process of charging and discharging, the uneven deposition-stripping of zinc ions leads to the growth of zinc dendrites, which leads to the deterioration of battery cycle performance, and even serious consequences such as short circuit in severe cases. A variety of methods have been proposed to guide the uniform deposition of zinc and suppress side reactions, such as three-dimensional electrode structure design, electrolyte additives, etc., but the above methods have complex and cumbersome preparation processes and poor cycle performance of electrode materials at high current densities. This limits the large-scale application of the above methods. Therefore, it is an urgent problem to be solved in the prior art to develop a modified zinc anode material that is simple and convenient in preparation process and can be cycled stably under high current density.

Contents of the invention

The purpose of the present invention is to provide a method for preparing a modified zinc negative electrode modified by a multifunctional interface layer. The method provided by the present invention has a simple and convenient preparation process, is suitable for large-scale production, and the prepared modified zinc anode modified by a multifunctional interface layer The negative electrode has excellent cycle performance at high current density.

In order to achieve the above-mentioned purpose of the invention, the present invention provides the following technical solutions:

The invention provides a method for preparing a modified zinc negative electrode modified by a multifunctional interface layer, comprising the following steps:

(1) After mixing silver halide and selenium, they are ground to obtain mixed powder;

(2) After mixing the mixed powder obtained in the step (1) with ethylenediamine, stirring under the condition of avoiding light and sealing to obtain a precipitate;

(3) washing and vacuum-drying the precipitate obtained in the step (2) in sequence to obtain silver selenide;

(4) Covering the silver selenide obtained in the step (3) on the surface of the zinc sheet, performing hot pressing treatment, forming a ZnSe-Ag interface layer on the surface of the zinc sheet, and obtaining a modified zinc negative electrode modified with a multifunctional interface layer.

Preferably, the ratio of silver halide to selenium in the step (1) is (1.8-2.4):1.

Preferably, the ratio of the amount of the selenium substance to the volume of the organic solvent in the step (2) is 1 mol: (20-28) mL.

Preferably, the stirring time in the step (2) is 40-54 hours.

Preferably, the washing in step (3) is followed by centrifugal washing with absolute ethanol and centrifugal washing with deionized water.

Preferably, the rotation speed of the absolute ethanol centrifugal cleaning is 4000-5000r/min, and the time of the absolute ethanol centrifugal cleaning is 3-10min.

Preferably, the vacuum drying temperature in the step (3) is 75-85° C., and the vacuum drying time is 22-26 hours.

Preferably, the diameter*thickness of the zinc sheet in the step (4) is (1~1.4) cm*(180~220) μm.

Preferably, the pressure of the hot-pressing treatment in the step (4) is 50-100 MPa, the temperature of the hot-pressing treatment is 180-230° C., and the time of the hot-pressing treatment is 1.5-3 hours.

Preferably, the thickness of the ZnSe-Ag interface layer in the step (4) is 0.5-4 μm.

The invention provides a method for preparing a modified zinc negative electrode modified by a multifunctional interface layer. Firstly, silver halide is mixed with selenium, and then ground to obtain a mixed powder. Stir under low temperature to obtain a precipitate, which is washed and vacuum-dried in sequence to obtain silver selenide powder; then the silver selenide powder is covered on the surface of the zinc sheet, and hot-pressed to form a ZnSe-Ag interface layer on the surface of the zinc sheet , to obtain a modified zinc anode modified with a multifunctional interfacial layer. The method provided by the present invention uses the in-situ displacement reaction (Ag ₂ Se+Zn→ZnSe+2Ag) to generate a multifunctional ZnSe-Ag interface layer on the surface of the zinc negative electrode. On the one hand, the ZnSe-Ag interface layer can reduce the concentration of zinc ions. The nucleation overpotential guides the uniform deposition of zinc ions, effectively inhibits the growth of dendrites, and greatly improves the service life and cycle performance of the battery. On the other hand, the ZnSe-Ag interface layer acts as a physical barrier to block the interaction between the zinc negative electrode and water molecules. contact, which effectively solves the technical problems of side reactions such as hydrogen evolution and corrosion in the zinc negative electrode of the aqueous zinc-ion battery, avoids the passivation of the negative electrode surface and the consumption of active zinc, prolongs the service life of the battery, and promotes high specific energy and stability. The practical process of the circulating water system zinc ion battery, the method provided by the invention has simple operation and simple reaction conditions, and can realize large-scale application. The results of the examples show that the electrolyte contact angle of ZnSe-Ag@Zn-50 in Example 1 of the present invention is 18.16°, which is significantly smaller than the contact angle (62.11°) of the unmodified zinc negative electrode in Comparative Example 1. Example 1 The prepared multifunctional interfacial layer modified zinc anode has stronger electrolyte affinity; compared with the unmodified zinc anode in Comparative Example 1, ZnSe-Ag@Zn-50 and ZnSe-Ag@Zn-100 show lower The nucleation barrier and better cycle stability; the symmetrical battery assembled by ZnSe-Ag@Zn-50 shows better rate performance than the symmetrical battery assembled by unmodified zinc electrode; comparative example 1 after 200 cycles There are a large number of zinc dendrites on the surface of the unmodified zinc electrode, but no dendrites are formed on the surface of the ZnSe-Ag@Zn-50 electrode, which realizes the uniform deposition of ions and can effectively inhibit the zinc dendrites; at a current of 5mA·cm ^-2 After depositing zinc at a high density for 1 hour, obvious zinc dendrites and bubbles can be seen in the cross-section of the unmodified zinc electrode in Comparative Example 1, while ZnSe-Ag@Zn-50 achieves uniform deposition without bubbles, which can effectively suppress dendrites. Crystal growth and hydrogen evolution reaction.

Description of drawings

Figure 1 is the XRD pattern of ZnSe-Ag@Zn-50 prepared in Example 1 of the present invention and the unmodified zinc negative electrode in Comparative Example 1, namely BareZn;

Figure 2 is a TEM image of ZnSe-Ag@Zn-50 prepared in Example 1 of the present invention;

Fig. 3 is the SEM image and corresponding element distribution diagram of ZnSe-Ag@Zn-50 prepared in Example 1 of the present invention;

Fig. 4 is the SEM picture of the cross-section of ZnSe-Ag@Zn-50 prepared in Example 1 of the present invention;

Fig. 5 is the static contact angle test diagram of the obtained ZnSe-Ag@Zn-50 prepared in Example 1 of the present invention and the unmodified zinc negative electrode in Comparative Example 1 to the electrolyte;

Fig. 6 is a cycle performance diagram of symmetrical batteries assembled with ZnSe-Ag@Zn-50 prepared in Example 1 of the present invention, ZnSe-Ag@Zn-100 prepared in Example 2 and the unmodified zinc negative electrode in Comparative Example 1;

Fig. 7 is a comparison chart of the rate performance of the ZnSe-Ag@Zn-50 assembled symmetrical battery prepared in Example 1 of the present invention and the unmodified zinc electrode assembled symmetrical battery in Comparative Example 1;

Fig. 8 is a linear sweep curve (LSV) diagram of the ZnSe-Ag@Zn-50 prepared in Example 1 of the present invention and the unmodified zinc electrode in Comparative Example 1;

Fig. 9 is the XRD pattern of the ZnSe-Ag@Zn-50 electrode prepared in Example 1 and the unmodified zinc electrode in Comparative Example 1 after 200 cycles of the symmetrical battery in the present invention;

Figure 10 is the SEM image of the ZnSe-Ag@Zn-50 electrode prepared in Example 1 and the surface morphology of the unmodified zinc electrode in Comparative Example 1 after the symmetrical battery in the present invention has been cycled for 200 cycles;

Fig. 11 is an in-situ optical microscope image of the ZnSe-Ag@Zn-50 prepared in Example 1 of the present invention and the unmodified zinc electrode in Comparative Example 1 after zinc deposition.

Detailed ways

The invention provides a method for preparing a modified zinc negative electrode modified by a multifunctional interface layer, comprising the following steps:

(1) After mixing silver halide and selenium, they are ground to obtain mixed powder;

(2) After mixing the mixed powder obtained in the step (1) with ethylenediamine, stirring under the condition of avoiding light and sealing to obtain a precipitate;

(3) washing and vacuum-drying the precipitate obtained in the step (2) in sequence to obtain silver selenide;

(4) Covering the silver selenide obtained in the step (3) on the surface of the zinc sheet, performing hot pressing treatment, forming a ZnSe-Ag interface layer on the surface of the zinc sheet, and obtaining a modified zinc negative electrode modified with a multifunctional interface layer.

In the present invention, unless otherwise specified, the raw materials used are conventional commercially available products in this field.

The invention mixes silver halide and selenium, and then grinds to obtain mixed powder.

In the present invention, the silver halide is preferably one or more of silver chloride or silver bromide.

In the present invention, the ratio of silver halide to selenium is preferably (1.8-2.4):1, more preferably (1.9-2.1):1, even more preferably 2:1.

In the present invention, there is no special limitation on the grinding method, and the method well known in the art can be used for grinding.

After the mixed powder is obtained, the present invention mixes the mixed powder with ethylenediamine, and then stirs under the conditions of avoiding light and sealing to obtain a precipitate.

In the present invention, the ratio of the amount of the selenium substance to the volume of the organic solvent is preferably 1 mol: (20-28) mL, more preferably 1 mol: (23-26) mL. The present invention controls the ratio of the amount of the selenium substance to the volume of the organic solvent to be in the above-mentioned range, so as to promote the full reaction of the silver halide and the selenium, and convert it into silver selenide.

In the present invention, the stirring temperature is room temperature. In the present invention, the stirring time is preferably 40~54h, more preferably 45~52h. The present invention controls the temperature and time of stirring within the above range to promote the full reaction of silver halide and selenium to be converted into silver selenide.

After the stirring is completed, the present invention preferably filters the stirred product to obtain a precipitate.

The present invention has no special limitation on the filtering method, and the solid-liquid separation can be achieved by a method well known in the art.

After obtaining the precipitate, the present invention sequentially washes and vacuum-dries the precipitate to obtain silver selenide;

In the present invention, the washing is preferably followed by centrifugal washing with absolute ethanol and centrifugal washing with deionized water. In the present invention, the rotational speed of the absolute ethanol centrifugal cleaning is preferably 4000-5000r/min, more preferably 4300-4800r/min. In the present invention, the time for centrifugal cleaning with absolute ethanol is preferably 3-10 minutes, more preferably 4-8 minutes. In the present invention, the number of times of centrifugal washing with absolute ethanol is preferably 2 to 6 times, more preferably 4 to 5 times. The present invention controls the rotational speed and time of the centrifugal cleaning of absolute ethanol within the above-mentioned range, so as to remove the organic component impurities in the sediment.

In the present invention, the rotational speed of the deionized water centrifugal cleaning is preferably 4000~5000r/min, more preferably 4300~4800r/min. In the present invention, the deionized water centrifugal cleaning time is preferably 3-10 minutes, more preferably 4-8 minutes. The present invention controls the rotational speed and time of centrifugal cleaning of deionized water within the above range, so as to remove the impurities of inorganic components in the sediment. The present invention has no special limitation on the times of centrifugal washing with deionized water, and it only needs to realize washing until the washing liquid becomes neutral.

After the washing is completed, the present invention preferably filters the washed product to obtain a solid.

The present invention has no special limitation on the filtering method, and the solid-liquid separation can be achieved by a method well known in the art.

After the solid is obtained, the present invention vacuum-dries the solid to obtain silver selenide.

In the present invention, the temperature of the vacuum drying is preferably 75-85°C, more preferably 78-83°C. In the present invention, the vacuum drying time is preferably 22-26 hours, more preferably 23-25 hours.

After the silver selenide is obtained, the present invention covers the silver selenide on the surface of the zinc flake, performs hot pressing treatment, forms a ZnSe-Ag interface layer on the surface of the zinc flake, and obtains a modified zinc negative electrode modified with a multifunctional interface layer.

The covering method of the present invention is preferably uniform covering by using a screen.

In the present invention, the diameter*thickness of the zinc sheet is preferably (1-1.4) cm*(180-220) μm, more preferably 1.2 cm*200 μm.

In the present invention, the zinc flakes are preferably pre-treated before use.

In the present invention, the pretreatment preferably includes grinding the surface of the zinc flakes, and then sequentially washing the polished zinc flakes with ethanol and vacuum drying. The present invention removes the oxide layer on the surface by performing pretreatment on the zinc flakes, so as to facilitate the subsequent direct contact and full reaction between the zinc flakes and Ag ₂ Se.

In the present invention, the sandpaper used for grinding is preferably 2300-3800 mesh, more preferably 2500-3500 mesh, and even more preferably 3000 mesh. The present invention has no special limitation on the way of ethanol cleaning, and it only needs to realize the removal of impurities on the surface of the zinc flakes. The present invention has no special limitation on vacuum drying, as long as the purpose of solvent removal can be achieved.

In the present invention, the pressure of the hot-pressing treatment is preferably 50-100 MPa. In the present invention, the temperature of the hot pressing treatment is preferably 180-230°C, more preferably 190-220°C. In the present invention, the time for the hot-pressing treatment is preferably 1.5-3 hours, more preferably 2 hours. The present invention controls the pressure and temperature of the hot pressing treatment within the above ranges to ensure that the zinc flakes and Ag ₂ Se can fully contact and react; and controls the time within the above ranges to ensure that a complete interfacial layer can be formed on the surface of the zinc flakes. A complete interfacial layer can completely block the contact between water and zinc anode, which is beneficial to inhibit hydrogen evolution and corrosion reactions; at the same time, it provides more active sites and promotes the uniform deposition of Zn ²⁺ .

In the present invention, the thickness of the ZnSe-Ag interface layer is preferably 0.5-4 μm, more preferably 1-3 μm, more preferably 2 μm. The invention controls the thickness of the ZnSe-Ag interface layer within the above range to improve the modification effect and obtain a modified zinc negative electrode modified by a multifunctional interface layer with excellent cycle performance under high current density.

The preparation method of the modified zinc negative electrode modified by the multifunctional interface layer provided by the invention has simple operation, mild reaction conditions, and is suitable for large-scale production.

The technical solutions in the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Apparently, the described embodiments are only some of the embodiments of the present invention, but not all of them. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

Example 1

A method for preparing a modified zinc negative electrode modified by a multifunctional interface layer, the steps are as follows:

(1) Weigh 2.87g of AgCl and mix with 0.87g of Se powder, grind and mix evenly to obtain mixed powder;

(2) After mixing the mixed powder obtained in the step (1) with 25ml of ethylenediamine, transfer it to a 30mL brown reagent bottle, seal the stopper, carry out stirring reaction on a magnetic stirrer for 48h, and obtain a black precipitate after filtration;

(3) The black precipitate obtained in the step (2) was washed with anhydrous ethanol ion for 4 times, and then centrifuged and washed with deionized water several times until the solution was neutral, then filtered to obtain a solid, and the solid was Dry in vacuum at 80°C for 24 hours to obtain silver selenide powder;

(4) Cover the silver selenide powder obtained in the above step (3) evenly on the surface of the zinc sheet with a screen, place it in a hot press, and perform hot pressing treatment at 200 ° C and 50 MPa for 2 hours to obtain a multifunctional interfacial layer modified Modified zinc anode, denoted as ZnSe-Ag@Zn-50;

The zinc sheet is pre-treated before use; the pre-treatment is to polish the surface of the zinc sheet with 3000-mesh sandpaper, then clean it with absolute ethanol and then vacuum-dry it.

Example 2

According to the method of Example 1, a modified zinc negative electrode modified with a multifunctional interface layer was prepared, which was designated as ZnSe-Ag@Zn-100. The difference from Example 1 is that the pressure of the hot-pressing treatment in the step (4) is 100 MPa .

Comparative example 1

The surface of the zinc sheet was polished with 3000-grit sandpaper, then washed with ethanol and dried in vacuum to obtain an unmodified zinc negative electrode, which was recorded as Bare Zn, without any other treatment.

The XRD patterns of the ZnSe-Ag@Zn-50 prepared in Example 1 and the unmodified zinc anode in Comparative Example 1 obtained by X-ray diffractometer are shown in FIG. 1 . It can be seen from Figure 1 that, compared with the standard PDF card, it proves that the ZnSe-Ag interface layer was successfully formed on the surface of the modified zinc negative electrode modified by the multifunctional interface layer in Example 1.

The modified zinc negative electrode modified by the multifunctional interfacial layer prepared in Example 1 was observed with a transmission electron microscope, and a TEM image was obtained, as shown in Figure 2; as can be seen from Figure 2, the lattice fringes and the respective lattice fringes of ZnSe and Ag can be clearly seen Obvious grain boundaries confirm the existence of the ZnSe-Ag interface layer on the surface of the modified zinc negative electrode modified by the multifunctional interface layer in Example 1.

The SEM figure and the corresponding element distribution figure of the modified zinc negative electrode surface modified by the multifunctional interfacial layer obtained in Example 1 obtained by scanning electron microscope observation and the corresponding element distribution figure are shown in Figure 3, and the SEM figure of the cross section is shown in Figure 4, by Figures 3 and 4 It can be seen that the Ag and Se elements on the surface and cross-section of the modified zinc negative electrode modified by the multifunctional interface layer obtained in Example 1 are evenly distributed, and the thickness of the ZnSe-Ag interface layer is 2 μm.

The static contact angle test of the modified zinc negative electrode modified by the multifunctional interfacial layer of the gained embodiment 1 and the unmodified zinc negative electrode of comparative example 1 to the static contact angle test of the electrolyte, obtain the static contact angle test diagram as shown in Figure 5; as can be seen from Figure 5 It is found that the electrolyte contact angle of the modified zinc negative electrode modified by the multifunctional interface layer prepared in Example 1 is 18.16°, which is significantly smaller than the contact angle (62.11°) of the unmodified zinc negative electrode in Comparative Example 1, indicating that Example 1 The prepared multifunctional interfacial layer-modified modified zinc anode has stronger electrolyte affinity.

Electrical performance testing method: ZnSe-Ag@Zn-50 prepared in Example 1, ZnSe-Ag@Zn-100 prepared in Example 2 and the unmodified zinc negative electrode in Comparative Example 1 were assembled into 2032 symmetrical button batteries respectively, using new The Wei battery test system performs constant current charge and discharge at a current density of 5mAh·cm ^-2 .

(1) Use the above-mentioned electrical performance detection method to detect the cycle performance, and obtain the ZnSe-Ag@Zn-50 prepared in Example 1, the ZnSe-Ag@Zn-100 prepared in Example 2, and the unmodified zinc negative electrode in Comparative Example 1. The cycle performance diagram of the assembled 2032 symmetrical battery is shown in Figure 6; it can be seen from Figure 6 that compared with the unmodified zinc anode in Comparative Example 1, ZnSe-Ag@Zn-50 and ZnSe-Ag@Zn-100 showed more The low nucleation barrier and better cycle stability indicate that the modified zinc anode modified by the multifunctional interfacial layer prepared in Example 1 and Example 2 can effectively improve the cycle performance of the battery.

(2) Using the above electrical performance detection method to detect the rate performance, the rate performance comparison of the ZnSe-Ag@Zn-50 assembled symmetric battery prepared in Example 1 and the unmodified zinc electrode assembled symmetric battery in Comparative Example 1 is obtained. As shown in Figure 7; it can be seen from Figure 7 that the symmetrical battery assembled with ZnSe-Ag@Zn-50 exhibits better rate performance than the symmetrical battery assembled with unmodified zinc electrode when the current density is changed during cycling.

(3) The linear sweep curve (LSV) diagram of the ZnSe-Ag@Zn-50 prepared in Example 1 and the unmodified zinc electrode in Comparative Example 1 is shown in Figure 8 by using the above electrical performance testing method; It can be seen that the corrosion potential of ZnSe-Ag@Zn-50 is more positive than that of the unmodified zinc electrode, and the corrosion current is smaller, indicating that ZnSe-Ag@Zn-50 has excellent corrosion resistance.

(4) Using the above-mentioned electrical performance detection method, after the symmetrical battery was cycled for 200 cycles, the XRD patterns of the ZnSe-Ag@Zn-50 electrode and the unmodified zinc electrode in Comparative Example 1 were detected, as shown in Figure 9; It can be seen from Figure 9 that obvious by-products appeared on the surface of the unmodified zinc anode in Comparative Example 1. This by-product is insulating and has no electrochemical activity, which seriously hinders the transport of zinc ions and electrons, while ZnSe-Ag@Zn- The surface of the 50 electrode still showed the same diffraction peaks as the pristine state, indicating that the side reactions were effectively suppressed.

(5) Using the above-mentioned electrical performance detection method, after the symmetrical battery was cycled for 200 cycles, the SEM images of the surface morphology of the ZnSe-Ag@Zn-50 electrode and the unmodified zinc electrode in Comparative Example 1 were detected, as shown in Figure 10 As shown in Figure 10, it can be seen that there are a large number of zinc dendrites on the surface of the unmodified zinc electrode in Comparative Example 1 after 200 cycles, but no dendrites are formed on the surface of the ZnSe-Ag@Zn-50 electrode, and the uniformity of ions is achieved. It shows that the modified zinc anode modified by the multifunctional interfacial layer prepared in Example 1 can effectively suppress zinc dendrites.

After zinc was deposited for 1 h at a current density of 5 mA cm ^-2 , the morphology of the electrode was observed with a light microscope, and the modified zinc electrode prepared in Example 1 and the unmodified zinc electrode in Comparative Example 1 were obtained. The in-situ optical microscope image after zinc deposition is shown in Figure 11; it can be seen from Figure 11 that in the cross-section of the unmodified zinc electrode in Comparative Example 1, obvious zinc dendrites and bubbles can be seen, while ZnSe-Ag@Zn-50 achieves The uniform deposition without air bubbles shows that the ZnSe-Ag@Zn-50 electrode can effectively inhibit the dendrite growth and hydrogen evolution reaction.

In summary, the ZnSe-Ag interface layer was successfully formed on the surface of the modified zinc negative electrode modified by the multifunctional interface layer in Example 1 of the present invention, and the electrolyte contact angle of ZnSe-Ag@Zn-50 was 18.16°, which was significantly smaller than that of the comparative example The contact angle of the unmodified zinc negative electrode in 1 (62.11°), the electrolyte affinity of the modified zinc negative electrode modified by the multifunctional interface layer prepared in Example 1 is stronger; compared with the unmodified zinc negative electrode of Comparative Example 1, ZnSe -Ag@Zn-50 and ZnSe-Ag@Zn-100 show lower nucleation barrier and better cycle stability; ZnSe-Ag@Zn-50 assembled symmetric battery is better than unmodified Zn electrode Symmetrical batteries show better rate performance; after 200 cycles, there are a large number of zinc dendrites on the surface of the unmodified zinc electrode in Comparative Example 1, while there is no dendrite formation on the surface of the ZnSe-Ag@Zn-50 electrode, realizing the ionization The uniform deposition of zinc can effectively inhibit zinc dendrites; after depositing zinc at a current density of 5mA cm ^-2 for 1h, obvious zinc dendrites and bubbles can be seen in the cross-section of the unmodified zinc electrode in Comparative Example 1, while ZnSe-Ag @Zn-50 achieves uniform deposition without bubbles, which can effectively inhibit dendrite growth and hydrogen evolution reaction. The modified zinc negative electrode material modified by the multifunctional interface layer prepared by the present invention can reduce the nucleation barrier in the zinc ion deposition process, uniform ion flux, and realize dendrite-free deposition; at the same time, the interface layer acts as a physical barrier to effectively block the zinc negative electrode The contact with the water electrolyte can suppress side reactions such as hydrogen evolution and corrosion, and the method provided by the invention has simple reaction conditions and easy operation, and can realize large-scale production.

The above is only a preferred embodiment of the present invention, it should be pointed out that, for those of ordinary skill in the art, without departing from the principle of the present invention, some improvements and modifications can also be made, and these improvements and modifications can also be made. It should be regarded as the protection scope of the present invention.

Claims (9)

1. A preparation method of a modified zinc negative electrode modified by a multifunctional interface layer, comprising the following steps: (1) After mixing silver halide and selenium, they are ground to obtain mixed powder; (2) After mixing the mixed powder obtained in the step (1) with ethylenediamine, stirring under the condition of avoiding light and sealing to obtain a precipitate; (3) washing and vacuum-drying the precipitate obtained in the step (2) in sequence to obtain silver selenide; (4) Covering the silver selenide obtained in the step (3) on the surface of the zinc sheet, performing hot-pressing treatment, forming a ZnSe-Ag interface layer on the surface of the zinc sheet, and obtaining a modified zinc negative electrode modified with a multifunctional interface layer; In the step (4), the pressure of the hot-pressing treatment is 50-100 MPa, the temperature of the hot-pressing treatment is 180-230° C., and the time of the hot-pressing treatment is 1.5-3 hours. 2. The method for preparing a modified zinc negative electrode modified by a multifunctional interface layer according to claim 1, wherein the ratio of the amount of silver halide to selenium in the step (1) is (1.8~2.4) :1. 3. The preparation method of the modified zinc negative electrode modified by the multifunctional interface layer according to claim 1, characterized in that, the amount of selenium in the step (1) and the amount of ethylenediamine in the step (2) The volume ratio is 1mol: (20~28) mL. 4 . The method for preparing a modified zinc negative electrode modified with a multifunctional interface layer according to claim 1 , wherein the stirring time in the step (2) is 40 to 54 hours. 5 . The method for preparing a modified zinc negative electrode modified with a multifunctional interface layer according to claim 1 , wherein the washing in the step (3) is performed sequentially by centrifugal washing with absolute ethanol and centrifugal washing with deionized water. 6 . 6. the preparation method of the modified zinc negative electrode of multifunctional interfacial layer modification according to claim 5, it is characterized in that, the rotating speed of described dehydrated alcohol centrifugal cleaning is 4000 ~ 5000r/min, described dehydrated alcohol centrifugal cleaning The time is 3~10min. 7. The method for preparing a modified zinc negative electrode modified by a multifunctional interface layer according to claim 1, characterized in that, the vacuum drying temperature in the step (3) is 75-85°C, and the vacuum drying time is It is 22~26h. 8. The method for preparing a modified zinc negative electrode modified by a multifunctional interface layer according to claim 1, wherein the diameter*thickness of the zinc sheet in the step (4) is (1~1.4) cm*(180 ~220) μm. 9 . The method for preparing a modified zinc negative electrode modified with a multifunctional interface layer according to claim 1 , wherein the thickness of the ZnSe-Ag interface layer in the step (4) is 0.5-4 μm.