A layered zinc composite electrode, a preparation method thereof and a zinc ion battery

Abstract

The application discloses a layered zinc composite electrode and a preparation method and a zinc ion battery thereof, and the preparation method comprises the following steps: (1) tin foil is immersed into a copper salt solution, a copper layer is formed on the surface of the tin foil, and a Sn / Cu composite current collector is prepared; and (2) the Sn / Cu composite current collector is immersed into a zinc salt solution, a zinc layer is formed on the surface of the copper layer, and a Sn / Cu / Zn layered composite electrode is prepared. The layered zinc composite electrode prepared by the application exhibits excellent electrochemical performance in a symmetric battery and a full battery, has important guiding significance for the design and preparation of a long-life zinc ion battery negative electrode, and has important value for promoting the practical application of the zinc ion battery.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of aqueous rechargeable zinc ion batteries, in particular to a layered zinc composite electrode, a preparation method thereof and a zinc ion battery. BACKGROUND

[0002] In recent years, multivalent ion batteries (such as Al 3+ , Mg 2+ , Ca 2+ and Zn 2+ batteries) have gradually attracted the attention of researchers, among which aqueous rechargeable zinc ion batteries are favored due to their high safety, fast charging and discharging, and direct use of zinc metal anode. At present, the research on zinc ion batteries mainly focuses on seeking high-performance positive electrode materials and their reaction mechanism, while less attention is paid to zinc anodes. During continuous charging and discharging, the zinc anode has some problems such as dendrite growth, passivation and hydrogen evolution, which will lead to the failure of zinc ion batteries. In order to solve these problems, researchers have proposed some strategies to optimize the zinc anode, such as adding additives to the zinc anode or electrolyte, and changing the microstructure of the zinc anode. However, the deposition behavior of zinc on different metal surfaces may be different, and the metal substrate can significantly affect the electrochemical behavior of the zinc anode, but there is little known about the nucleation and electrodeposition / stripping behavior of zinc on various metal substrates, and there is also a lack of zinc anode materials for aqueous rechargeable zinc ion batteries with excellent performance.

[0003] It should be noted that the information disclosed in the above background section is only for understanding the background of the present application, and therefore can include information that does not constitute prior art known to those of ordinary skill in the art. SUMMARY

[0004] The present application provides a layered zinc composite electrode, a preparation method thereof and a zinc ion battery.

[0005] The present application adopts the following technical solutions:

[0006] In a first aspect, a preparation method of a layered zinc composite electrode is provided, which comprises the following steps:

[0007] (1) immersing a tin foil into a copper salt solution to form a copper layer on the surface of the tin foil, thereby preparing a Sn / Cu composite current collector;

[0008] (2) immersing the Sn / Cu composite current collector into a zinc salt solution to form a zinc layer on the surface of the copper layer, thereby preparing a Sn / Cu / Zn layered composite electrode.

[0009] In a second aspect, a layered zinc composite electrode prepared by the preparation method of the first aspect is provided.

[0010] In a third aspect, a zinc ion battery is provided, which comprises a positive electrode, an electrolyte, a separator and a negative electrode, the negative electrode being the layered zinc composite electrode of the first aspect, or both the positive electrode and the negative electrode being the layered zinc composite electrode of the first aspect.

[0011] The Sn / Cu / Zn layered composite electrode prepared by the present application has excellent electrochemical performance in both symmetric batteries and full batteries, has important guiding significance in the design and preparation of long-life zinc ion battery negative electrodes, and has important value in promoting the practical application of zinc ion batteries. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1a is a preparation flow chart of the Sn / Cu / Zn layered composite electrode of Example 1 of the present application;

[0013] Figure 1b is an SEM image before electrodeposition of zinc on the Ag|Cu bimetallic substrate and an EDS image after electrodeposition of zinc;

[0014] Figure 1c is an SEM image before electrodeposition of zinc on the Ti|Cu bimetallic substrate and an EDS image after electrodeposition of zinc;

[0015] Figure 1d is an SEM image before electrodeposition of zinc on the Cu|Sn bimetallic substrate and an EDS image after electrodeposition of zinc;

[0016] Figures 2a-2d are nucleation overpotential curve diagrams of zinc deposition on a Cu substrate in Comparative Example 1, zinc deposition on an Ag substrate in Comparative Example 2, zinc deposition on a Ti substrate in Comparative Example 3, and zinc deposition on a Sn substrate in Comparative Example 4, respectively;

[0017] Figure 3a is a result diagram of the interfacial binding energy of Zn with Cu, Ag, Ti, Sn and Zn obtained by DFT calculation;

[0018] Figure 3b is a TEM diagram of the Cu / Zn electrode obtained in Comparative Example 1;

[0019] Figure 3c is Figure 3b is a magnified view of the yellow dashed circle region in

[0020] Figure 3d is Figure 3c is an HRTEM diagram and an SAED diagram (inset) of the corresponding region;

[0021] Figures 4a-4eare the cycle performance plots of the respective symmetric cells of the pure zinc foil electrode, Cu / Zn electrode in Comparative Example 1, Ag / Zn electrode in Comparative Example 2, Ti / Zn electrode in Comparative Example 3, and Sn / Zn electrode in Comparative Example 4, respectively;

[0022] Figures 5a-5c are the LSV curves, SEM images before cycling, and SEM images after cycling of the Cu / Zn electrode in Comparative Example 1 in 1 M Na2SO4 electrolyte, respectively;

[0023] Figures 5d-5f are the LSV curves, SEM images before cycling, and SEM images after cycling of the Ag / Zn electrode in Comparative Example 2 in 1 M Na2SO4 electrolyte, respectively;

[0024] Figure 5g are the LSV curves, SEM images before cycling, and SEM images after cycling of the Ti / Zn electrode in Comparative Example 3 in 1 M Na2SO4 electrolyte, respectively;

[0025] Figures 5j-5l are the LSV curves, SEM images before cycling, and SEM images after cycling of the Sn / Zn electrode in Comparative Example 4 in 1 M Na2SO4 electrolyte, respectively;

[0026] Figure 6a is the SEM image of the Sn / Cu composite current collector prepared in step (1) of Example 1;

[0027] Figure 6b is the SEM image of the Sn / Cu / Zn layered composite electrode prepared in Example 1;

[0028] Figure 6c is the voltage-time curve of zinc electrodeposition on the Sn / Cu composite current collector of Example 1;

[0029] Figure 6d is the SEM image of the Sn / Cu / Zn composite electrode after cycling of Example 1;

[0030] Figure 6e is the cycle performance of the Sn / Cu / Zn || Sn / Cu / Zn symmetric cell of the Sn / Cu / Zn layered composite electrode in Example 1;

[0031] Figure 6f is the cycle performance of the Cu / Sn / Zn || Cu / Sn / Zn symmetric cell of the Cu / Sn / Zn electrode in Comparative Example 5;

[0032] Figure 6g is the V 10 O 24 || Sn / Cu / Zn and V 10 O24 ||Cycle performance of Zn-ion battery. DETAILED DESCRIPTION

[0033] The embodiments of the present application will be described in detail below. It should be emphasized that the following description is only exemplary and is not intended to limit the scope of the present application and its applications, and the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0034] The embodiment of the present application provides a preparation method of layered zinc composite electrode, as shown in the formula (I), which comprises the following steps: Figure 1a The embodiment of the present application provides a preparation method of layered zinc composite electrode, as shown in the formula (I), which comprises the following steps:

[0035] (1) immerging tin foil into copper salt solution to form a copper layer on the surface of the tin foil, and obtaining Sn / Cu composite current collector;

[0036] (2) immerging the Sn / Cu composite current collector into zinc salt solution to form a zinc layer on the surface of the copper layer, and obtaining Sn / Cu / Zn layered composite electrode.

[0037] In the preferred embodiment, the temperature of the copper salt solution in step (1) is 10-60℃, and the immerging time is 5-1000 seconds.

[0038] In the preferred embodiment, the copper salt solution contains copper salt with a concentration of 0.1-2M and acid with a concentration of 0.1-1M.

[0039] In the preferred embodiment, the copper salt is at least one of copper sulfate, copper chloride and copper nitrate, and the acid is at least one of sulfuric acid, hydrochloric acid and nitric acid.

[0040] In the preferred embodiment, step (1) is to immerge tin foil into copper salt solution to replace a copper layer on the surface of the tin foil by replacement method.

[0041] In the preferred embodiment, step (2) is to immerge the Sn / Cu composite current collector into zinc salt solution to form a zinc layer on the surface of the copper layer by electrodeposition.

[0042] In the preferred embodiment, the conditions of electrodeposition in step (2) are that the electrolyte contains 0.1-3mol / L of ZnSO4·7H2O, 0.2-1mol / L of Na2SO4 and 0.2-2mol / L of H3BO3, the current density is 0.1-100mA / cm 2 , the electrodeposition time is 10-1000 seconds, and the temperature range is 0-60℃.

[0043] The embodiment of the present application further provides a layered zinc composite electrode prepared by the preparation method.

[0044] The present application also provides a zinc ion battery comprising a positive electrode, an electrolyte, a separator and a negative electrode, wherein the negative electrode is the layered zinc composite electrode, or both the positive electrode and the negative electrode are the layered zinc composite electrode.

[0045] In a preferred embodiment, the zinc ion battery is a symmetric battery, wherein both the positive electrode and the negative electrode are the layered zinc composite electrode; or the zinc ion battery is a full battery, wherein the positive electrode is a vanadium oxide and the electrolyte is an aqueous zinc salt solution.

[0046] As shown in Figures 1b-1d , metal Ag and Ti were respectively electrodeposited on the surface of a metal Cu substrate, wherein the area of the deposited metal accounts for half of the area of the copper foil to obtain Ag|Cu and Ti|Cu, and Sn foil was half immersed in a Cu ion-containing solution to prepare a Cu|Sn bimetallic substrate by displacement reaction. Zinc was deposited on the prepared Ag|Cu, Ti|C and Cu|Sn bimetallic substrates, and the deposition behaviors of zinc on the two sides of the metal were compared, as shown in Figures 1b-1d , the results show that zinc selectively deposits on the surface of the Cu substrate, and the deposition sequence of zinc on different substrates is Cu > Sn > Ti and Ag. By performing zinc electrodeposition experiments on different bimetallic substrates (Ag|Cu, Ti|Cu and Cu|Sn), it is proved that zinc has the characteristics of preferential deposition on the Cu substrate, which provides experimental basis for the design of the subsequent Sn / Cu / Zn layered composite negative electrode. The present application is further described below by describing examples and comparative examples.

[0047] Example 1: Preparation of Sn / Cu / Zn layered composite electrode

[0048] The preparation of the Sn / Cu / Zn layered composite electrode comprises the following steps:

[0049] (1) Sn foil was immersed in an electroplating solution containing 0.94 M CuSO4 and 0.61 M H2SO4 for 20 seconds without applying current to obtain a Sn / Cu composite current collector;

[0050] (2) A 10-micron-thick layer of zinc was electrodeposited on the obtained Sn / Cu composite current collector to obtain a Sn / Cu / Zn layered composite electrode. Specifically:

[0051] (2.1) The prepared Sn / Cu composite current collector was used as a working electrode, a platinum sheet was used as a counter electrode, and an Ag / AgCl electrode was used as a reference electrode.

[0052] (2.2) The electrode was immersed in a zinc salt solution containing 62.5 g of ZnSO4·7H2O, 62.5 g of Na2SO4 and 10 g of H3BO3, and 500 mL of deionized water, and the temperature was 25°C.

[0053] (2.3) The constant current density was 40 mA cm -2 The electrodeposition was performed for 540 seconds.

[0054] (2.4) The electrode was taken out, washed with deionized water and ethanol, and dried to obtain a Sn / Cu / Zn layered composite electrode.

[0055] Preparation of Cu / Zn electrode

[0056] A copper foil was used as a substrate, and zinc was deposited on the surface thereof to obtain a Cu / Zn electrode.

[0057] Preparation of Ag / Zn electrode

[0058] A silver foil was used as a substrate, and zinc was deposited on the surface thereof to obtain an Ag / Zn electrode.

[0059] Preparation of Ti / Zn electrode

[0060] A titanium foil was used as a substrate, and zinc was deposited on the surface thereof to obtain a Ti / Zn electrode.

[0061] Preparation of Sn / Zn electrode

[0062] A tin foil was used as a substrate, and zinc was deposited on the surface thereof to obtain a Sn / Zn electrode.

[0063] Preparation of Cu / Sn / Zn electrode

[0064] A Cu foil was used as a substrate, and Sn and Zn were electrodeposited thereon to obtain a Cu / Sn / Zn electrode. The above examples and respective comparative examples were subjected to performance tests

[0065] 1. Cell assembly and test

[0066] (1) The electrodes prepared in Example 1 and Comparative Examples 1 to 5 were used to assemble Zn||Zn, Cu / Zn||Cu / Zn, Ag / Zn||Ag / Zn, Ti / Zn||Ti / Zn, Sn / Zn||Sn / Zn, Cu / Sn / Zn||Cu / Sn / Zn and Sn / Cu / Zn||Sn / Cu / Zn symmetrical cells, respectively, and the cyclic performance thereof was tested at a current density of 0.5 mA cm -2 .

[0067] (2) The electrodes prepared in Example 1 and pure zinc were used to assemble V 10 O 24 ||Sn / Cu / Zn and V 10 O 24 ||Zn full cells, respectively, and the cyclic performance thereof was tested at a current density of 1 Ag -1 .

[0068] Specifically, V 10 O 24 , conductive carbon black and binder (PVDF) were mixed in a mass ratio of 7:2:1, N-methyl pyrrolidone was added, stirred for 6-8 hours to prepare a slurry; the slurry was coated on a stainless steel foil and dried for 12 hours to obtain V 10 O 24 positive electrode; V 10 O 24 positive electrode, the Sn / Cu / Zn composite electrode prepared in Example 1 as the negative electrode or pure zinc foil as the negative electrode, 2MZnSO4 electrolyte and glass fiber separator were assembled to prepare V 10 O 24 ||Sn / Cu / Zn and V 10 O 24 ||Zn full cell.

[0069] 2. Characterization and calculation

[0070] The morphology and structure of the materials were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), etc. The binding energy of zinc and different metal substrates was calculated by density functional theory (DFT).

[0071] 3. Results

[0072] Figures 2a-2d is the nucleation overpotential curve of zinc on copper, silver, titanium and tin substrates, wherein Figure 2a is the nucleation overpotential curve of zinc deposition on Cu substrate in Comparative Example 1, and the nucleation overpotential is 0 mV; Figure 2b is the nucleation overpotential curve of zinc deposition on Ag substrate in Comparative Example 2, and the nucleation overpotential is 4 mV; Figure 2c is the nucleation overpotential curve of zinc deposition on Ti substrate in Comparative Example 3, and the nucleation overpotential is 200 mV; Figure 2d is the nucleation overpotential curve of zinc deposition on Sn substrate in Comparative Example 4, and the nucleation overpotential is 70 mV. It can be seen that: Figures 2a-2d the nucleation overpotential of zinc on different metal substrates is different, and the deposition nucleation overpotential of zinc on Cu substrate is the lowest, which indicates that zinc is more likely to nucleate and grow on the surface of Cu, further proving the advantage of Cu as the zinc negative electrode current collector.

[0073] Figures 3a-3d is the calculation result of the binding energy of zinc and different metals and the TEM characterization of Cu / Zn interface, wherein Figure 3a is the interface binding energy of Zn and Cu, Ag, Ti, Sn and Zn calculated by DFT, and the Zn-Cu interface binding energy is the highest (-0.22 eV), indicating that the interaction between Zn and Cu is the strongest; Figure 3bThis is a TEM image of the Cu / Zn electrode prepared in Comparative Example 1. The interface between the Cu and Zn layers can be clearly seen, with the yellow dashed line indicating the interface between the Cu and Zn layers. Figure 3c yes Figure 3b An enlarged view of the area circled in yellow in the image; Figure 3d for Figure 3c High-resolution TEM (HRTEM) and selected area electron diffraction (SAED) patterns (inset) of the corresponding region reveal lattice fringes of the CuZn and CuZn2 alloys, indicating the formation of a CuZn and CuZn2 alloy between the Zn and Cu layers. Figures 3a-3d It is known that zinc preferentially deposits on the Cu substrate, which is beneficial to improving the stability and cycle performance of the Cu / Zn electrode.

[0074] like Figures 4a-4e The figures show the cycle performance of different electrodes in a symmetrical cell (at 0.5 mA cm⁻¹). -2 Current density, 0.5 mA cm⁻¹ -2 (Testing its cycling performance under the condition of cutoff surface capacity), where, Figure 4a Cyclic performance of a symmetrical cell (Zn||Zn) with pure zinc foil electrodes at 0.5 mA cm⁻¹ -2 The polarization voltage fluctuated drastically after 55 hours of cycling at the current density, indicating that the pure zinc electrode has poor cycling stability. Figure 4b The cycling performance of the symmetrical cell (Cu / Zn||Cu / Zn) with Cu / Zn electrode in Comparative Example 1 is shown at 0.5 mA cm⁻¹. -2 After cycling for more than 200 hours at current density, the polarization voltage remained stable at around 20mV, indicating that the Cu / Zn electrode has excellent cycling stability. Figure 4c To illustrate the cycling performance of the Ag / Zn||Ag / Zn symmetric cell prepared in Comparative Example 2, the polarization voltage gradually increases during cycling, and the cell fails after 150 hours. Figure 4d To show the cycling performance of the Ti / Zn||Ti / Zn symmetric cell prepared in Comparative Example 3, the polarization voltage showed a sudden change after 30 hours of cycling, indicating that the cycling stability of the Ti / Zn electrode is poor. Figure 4e To assess the cycling performance of the Sn / Zn||Sn / Zn symmetric cell prepared in Comparative Example 4, the polarization voltage was gradually increased during cycling (from 10 mV to 20 mV), but remained below 20 mV after 200 h. Figures 4a-4e It is evident that, compared to pure zinc electrodes and Ag / Zn and Ti / Zn electrodes, Cu / Zn electrodes exhibit better cycle stability, while Sn / Zn electrodes also demonstrate good cycle performance, providing a reference for the design of Sn / Cu / Zn layered composite electrodes. The composite electrode of this invention exhibits an ultra-long cycle life in symmetrical cells, more than five times that of pure zinc foil anodes.

[0075] Figures 5a-5l is the linear sweep voltammetry (LSV) curve of the Cu / Zn electrode in 1 M Na2SO4 electrolyte, and the hydrogen evolution reaction potential is -1.96 V; Figure 5a is the LSV curve of the Cu / Zn electrode in Example 1 in 1 M Na2SO4 electrolyte, and the hydrogen evolution reaction potential is -1.96 V; Figure 5b is the SEM image of the Cu / Zn electrode in Example 1 before cycling, and it can be observed that the zinc with a layered structure is uniformly deposited on the surface of the Cu foil; Figure 5c is the SEM image of the Cu / Zn electrode in Example 1 after being cycled for 50 h at a current density of 0.5 mA cm-2, and some irregular granular deposits appear on the surface; -2 is the SEM image of the Cu / Zn electrode in Example 1 after being cycled for 50 h at a current density of 0.5 mA cm-2, and some irregular granular deposits appear on the surface; Figure 5d is the LSV curve of the Ag / Zn electrode in Comparative Example 2 in 1 M Na2SO4 electrolyte, and the hydrogen evolution reaction potential is -2.18 V; Figure 5e is the SEM image of the Ag / Zn electrode in Comparative Example 2 before cycling, and it can be observed that the zinc with a layered structure is uniformly deposited on the surface of the Ag foil, Figure 5f is the SEM image of the Ag / Zn electrode in Comparative Example 2 after being cycled for 50 h at a current density of 0.5 mA cm-2, and some irregular granular deposits appear on the surface; -2 is the SEM image of the Ag / Zn electrode in Comparative Example 2 after being cycled for 50 h at a current density of 0.5 mA cm-2, and some irregular granular deposits appear on the surface; Figure 5g is the LSV curve of the Ti / Zn electrode in Comparative Example 3 in 1 M Na2SO4 electrolyte, and the hydrogen evolution reaction potential is -2.09 V; Figure 5h is the SEM image of the Ti / Zn electrode in Comparative Example 3 before cycling, and the deposition morphology of zinc is uneven; Figure 5i is the SEM image of the Ti / Zn electrode in Comparative Example 3 after being cycled for 50 h at a current density of 0.5 mA cm-2, and some irregular granular deposits appear on the surface; -2 is the SEM image of the Ti / Zn electrode in Comparative Example 3 after being cycled for 50 h at a current density of 0.5 mA cm-2, and some irregular granular deposits appear on the surface; Figure 5j is the LSV curve of the Sn / Zn electrode in Comparative Example 4 in 1 M Na2SO4 electrolyte, and the hydrogen evolution reaction potential is -2.25 V; Figure 5k is the SEM image of the Sn / Zn electrode in Comparative Example 4 before cycling, and it can be observed that the zinc with a nanoflower structure is uniformly deposited on the surface of the Sn foil; Figure 5l is the SEM image of the Sn / Zn electrode in Comparative Example 4 after being cycled for 50 h at a current density of 0.5 mA cm-2, and the surface morphology of zinc remains basically unchanged without obvious granular deposits; -2 is the SEM image of the Sn / Zn electrode in Comparative Example 4 after being cycled for 50 h at a current density of 0.5 mA cm-2, and the surface morphology of zinc remains basically unchanged without obvious granular deposits; Figures 5a-5lThe results of LSV testing show that the Sn / Zn electrode has the highest hydrogen evolution overpotential and can effectively suppress the hydrogen evolution side reaction. SEM images before cycling show that the morphology of zinc differs on different metal substrates. Zinc on Cu / Zn, Ag / Zn, and Sn / Zn electrodes exhibits a layered structure, while zinc on the Ti / Zn electrode is more disordered. SEM images after 50 hours of cycling show irregular layered particles on the surfaces of Cu / Zn, Ag / Zn, and Ti / Zn electrodes, while the Sn / Zn electrode surface shows no obvious byproduct BZS. Therefore, the Sn / Zn electrode surface does not show significant BZS formation and exhibits better electrochemical stability. This further verifies the feasibility of Sn as a zinc anode current collector material.

[0076] Characterization and electrochemical performance testing of Sn / Cu / Zn layered composite electrodes, such as... Figures 6a-6f As shown, Figure 6a The image shows the SEM image of the Sn / Cu composite current collector prepared in Example 1. It can be seen that Cu is uniformly covered on the surface of the Sn foil. Figure 6b The image shows the SEM image of the Sn / Cu / Zn composite electrode prepared in Example 1, which shows that the Zn layer is uniform and dense. Figure 6c The voltage-time curve of zinc electrodeposition on Sn / Cu current collector in Example 1 shows that the nucleation overpotential is 0mV. Figure 6d The Sn / Cu / Zn composite electrode in Example 1 at 0.5 mA cm -2 The SEM image after 50 hours of cycling at the current density shows that there is no obvious BZS formation, indicating that the Sn / Cu / Zn composite electrode has good structural stability and can improve the electrochemical stability of the Sn / Cu / Zn composite electrode. Figure 6e The cycling performance of the Sn / Cu / Zn||Sn / Cu / Zn symmetric cell in Example 1 was measured at 0.5 mA / cm. -2 It can cycle for more than 250 hours at current density and maintain a stable polarization voltage of 10mV for at least 250 hours, which is far superior to pure zinc foil electrode symmetrical cells. Figure 6f The cycling performance of the Cu / Sn / Zn electrode prepared in Comparative Example 5, in a symmetrical cell (Cu / Sn / Zn||Cu / Sn / Zn), is shown at 0.5 mA cm⁻¹. -2 After cycling at current density for more than 200 hours, the polarization voltage shows an upward trend. Figure 6g V prepared in Example 1 10 O 24 ||Sn / Cu / Zn and V 10 O 24 The cycle performance of Zn zinc-ion batteries shows that: V 10O 24 The initial discharge capacity of the Sn / Cu / Zn battery was 184.6 mAh g -1 After 1000 cycles, the capacity remained at 130 mAh g -1 The above had a coulombic efficiency of 99.99%, i.e., after 1000 cycles at 1 Ag -1 The current density, the capacity retention and the coulombic efficiency were both high, in comparison, the V 10 O 24 The cycle stability of the Zn battery was poor, and the cycle life and the capacity retention were both lower than the V 10 O 24 The Sn / Cu / Zn battery. From Figures 6a-6g It can be seen that the Sn / Cu / Zn composite electrode combines the advantages of Cu and Sn, and has good electrochemical performance and cycle stability. The performance of the Sn / Cu / Zn electrode in the symmetric battery and the full battery is better than that of the pure zinc foil electrode and the Cu / Sn / Zn electrode, which indicates that it has application prospects as an electrode material for aqueous zinc ion batteries.

[0077] The above examples show that, due to the strong binding energy between Zn and Cu and the formation of CuZn and CuZn2 alloys between the Zn and Cu layers, zinc is preferentially deposited on the Cu substrate without nucleation overpotential, so that the Cu / Zn electrode has excellent cycle stability and reversibility. When Sn is used as the substrate, the hydrogen evolution reaction can be inhibited due to the high hydrogen evolution overpotential of the metal Sn, thereby reducing the generation of by-product basic zinc sulfate (BZS) and improving the electrochemical stability of the zinc electrode. The experimental results show that the Cu / Zn and Sn / Cu / Zn electrodes have excellent cycle stability, and the Sn / Zn electrode can inhibit the generation of by-product BZS. The Sn / Cu / Zn layered composite zinc electrode prepared by combining the advantages of Cu and Sn substrates has excellent electrochemical performance in the symmetric battery and the full battery.

[0078] The above further describes the present application in conjunction with specific / preferred embodiments, and cannot be deemed to limit the specific implementation of the present application to these descriptions. For those skilled in the art to which the present application belongs, without departing from the concept of the present application, they can make several substitutions or variations to the described embodiments, and these substitutions or variations shall be deemed to fall within the protection scope of the present application. In the description of the present application, the description of the terms "an embodiment", "some embodiments", "a preferred embodiment", "an example", "a specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are contained in at least one embodiment or example of the present application. In the present application, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In the case of no mutual contradiction, those skilled in the art can combine and combine the different embodiments or examples described in the present application and the features of the different embodiments or examples. Although the embodiments of the present application and their advantages have been described in detail, it should be understood that various changes, substitutions and modifications can be made herein without departing from the scope of protection of the patent application.

Claims

1. A method for producing a layered zinc composite electrode, characterized by, The method comprises the following steps: (1) dipping tin foil into a copper salt solution to form a copper layer on the surface of the tin foil by displacement, thereby obtaining a Sn / Cu composite current collector; (2) dipping the Sn / Cu composite current collector into a zinc salt solution to form a zinc layer on the surface of the copper layer by electrodeposition, thereby obtaining a Sn / Cu / Zn layered composite electrode.

2. The method for preparing a layered zinc composite electrode according to claim 1, characterized by: The temperature of the copper salt solution in step (1) is 10-60℃; the dipping time is 5-1000 seconds.

3. The method for preparing a layered zinc composite electrode according to claim 1, characterized by: The copper salt solution contains a copper salt with a concentration of 0.1-2M and an acid with a concentration of 0.1-1M.

4. The method for preparing a layered zinc composite electrode according to claim 3, characterized by: The copper salt is at least one of copper sulfate, copper chloride and copper nitrate, and the acid is at least one of sulfuric acid, hydrochloric acid and nitric acid.

5. The method of claim 1, wherein the layered zinc composite electrode is prepared by: The conditions of the electrodeposition in step (2) are: 0.1-3 mol / L of ZnSO4·7H2O, 0.2-1 mol / L of Na2SO4 and 0.2-2 mol / L of H3BO3 in the electrolyte, 0.1-100 mA / cm2 of current density, 10-1000 seconds of electrodeposition time and 0-60 ℃ of temperature range. 2 , 0.1-3 mol / L of ZnSO4·7H2O, 0.2-1 mol / L of Na2SO4 and 0.2-2 mol / L of H3BO3 in the electrolyte, 0.1-100 mA / cm2 of current density, 10-1000 seconds of electrodeposition time and 0-60 ℃ of temperature range.

6. A layered zinc composite electrode characterized in that, The method is prepared by any one of claims 1-5.

7. A zinc-ion battery, characterized in that, The zinc ion battery is a symmetric battery, wherein the positive electrode and the negative electrode are both the layered zinc composite electrode of claim 6; or the zinc ion battery is a full battery, wherein the positive electrode is a vanadium oxide and the electrolyte is an aqueous zinc salt solution.

8. The zinc-ion battery of claim 7, wherein, The zinc ion battery is a symmetric battery, wherein the positive electrode and the negative electrode are both the layered zinc composite electrode of claim 6; or the zinc ion battery is a full battery, wherein the positive electrode is a vanadium oxide and the electrolyte is an aqueous zinc salt solution.

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