A secondary zinc ion battery and a method for improving the coulombic efficiency and stable long cycle performance of a zinc negative electrode

Abstract

The application relates to a secondary zinc ion battery and a method for improving the coulomb efficiency and stable long cycle performance of a zinc negative electrode, which realizes the high coulomb efficiency of the zinc negative electrode of the zinc ion battery under large current and long cycle by the synergistic effect of zinc negative electrode surface modification and electrolyte additives, the surface modifier is a metal halide, is dissolved in a polar organic solution, and the electrolyte comprises a zinc salt, a metal ion additive and a solvent. Compared with the prior art, the cycle performance of the zinc negative electrode and the deposition morphology of zinc are significantly improved by the synergistic surface alloying and electrolyte additive, and the zinc negative electrode has excellent zinc deposition morphology and very high metal coulomb efficiency under a relatively high current density and discharge depth.

Description

Technical Field

[0001] This invention belongs to the field of secondary zinc-ion battery technology, and relates to a secondary zinc-ion battery and a method for achieving high coulombic efficiency and stable long-cycle operation of the zinc anode. Background Technology

[0002] The theoretical capacity of zinc (Zn) is 820 mAh g. -1 Or 5850mAh cm -3 With an electrode potential of -0.76V (vs. standard hydrogen electrode), rechargeable zinc-ion batteries (ZIBs) are among the most popular multivalent rechargeable batteries. Besides the Zn anode, ZIBs typically use MnO2, V2O5, VS2, etc., as the cathode, and an aqueous solution as the electrolyte. ZIBs offer advantages such as high safety, affordability, and environmental friendliness, making them more suitable for large-scale storage and commercial applications compared to lithium-ion and lead-acid batteries.

[0003] Zn is an amphoteric metal and is thermodynamically unstable in aqueous solutions, leading to four key problems at the negative electrode in aqueous ZIBs electrolytes: dendrite formation, passivation, self-corrosion, and deformation. These problems arise because: 1. Concentration polarization in the negative electrode / electrolyte causes Zn... 2+ Deposition exhibits hysteresis, and uneven current distribution affects Zn. 2+ Deposition causes protrusions in some areas and accelerates the deposition rate, leading to rapid dendrite growth; 2. Zinc at the edges preferentially dissolves during discharge, while Zn dissolves during charging. 2+ 1. It is difficult to replenish the zinc consumed at the initial position at the edge, and the electrode deforms as the cycle continues; 2. Zinc reacts with aqueous solution and is accompanied by H2 precipitation, Zn is gradually consumed, causing self-corrosion of the negative electrode; 3. Zn(OH)2 generated during battery charging and discharging decomposes on the Zn surface to form a dense ZnO film, which hinders Zn absorption. 2+ The dissolution and diffusion of the anode cause passivation due to decreased reactivity.

[0004] Current research on organic electrolytes for zinc oxide (ZIBs) mainly focuses on the compatibility of solvents, solutes, and additives, with promising results. However, compared to aqueous electrolytes, organic electrolytes that are thermodynamically stable for metallic zinc should be able to meet the requirements of applications at higher current densities. Most related studies have increased the stable operating current density of the zinc anode to 5 mA cm⁻¹. -2 Very few can reach 10 mA cm -2 20mA cm -2 Even 50mA cm -2 and 100mA cm -2Adding transition metal halides, such as SbF3 (J. Alloys Compd. 2024, 985, 174049) or SbCl3 (Adv. Sci. 2022, 9, 2104866), to aqueous electrolytes generates in-situ insoluble ZnF2 and an alloy barrier layer, which locally isolates the Zn anode from direct contact with the aqueous electrolyte, thus eliminating side reactions and stabilizing the interface to some extent. In contrast, the purpose of the aforementioned studies was to construct an isolation layer between water and the zinc anode to hinder side reactions between zinc and the aqueous electrolyte. The zinc anode and electrolyte modification presented in this paper aims to further adjust the zinc deposition morphology based on the intrinsic thermodynamic stability of the system, significantly suppressing zinc dendrite growth and improving coulombic efficiency and battery life. Summary of the Invention

[0005] The purpose of this invention is to provide a secondary zinc-ion battery and a method for improving the coulombic efficiency and stable long-cycle performance of the zinc anode. It also aims to effectively address the two key coupling issues of dendrite formation and interfacial side reactions in the Zn anode. This is achieved by using an organic electrolyte to construct a thermodynamically stable interface for the Zn anode, and by utilizing an alloy modification layer and electrolyte additives in synergy to regulate the three-dimensional dendrite growth mode of the Zn anode in the organic electrolyte into a two-dimensional planar dendrite-free mode. This results in a high-current, long-cycle, high-coulombic-efficiency anode for the secondary zinc-ion battery, achieving stable cycling with high coulombic efficiency under high-current conditions.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] In one aspect, the present invention provides a secondary zinc-ion battery, comprising a zinc negative electrode, a positive electrode, and an electrolyte, wherein the electrolyte contains zinc salt, metal ion additives, and an organic solvent with a boiling point exceeding 100°C.

[0008] In this invention, the additives in the electrolyte promote the directional deposition of zinc ions at the negative electrode interface, resulting in deposited zinc with a specific hexagonal particle structure, which effectively suppresses the formation of dendrites.

[0009] Furthermore, the zinc anode is surface-modified using a metal halide solution. The solute (i.e., surface modifier) ​​in the metal halide solution is selected from one or more combinations of metal halides such as calcium fluoride (CaF2), antimony fluoride (SbF3), lead fluoride (PbF2), tin fluoride (SnF2), magnesium fluoride (MgF2), chromium fluoride (CrF3), antimony chloride (SbCl3), tin chloride (SnCl2), and chromium chloride (CrCl3). The alloy layer of the zinc anode has abundant nucleation sites and a lower nucleation energy barrier than the zinc metal surface. This interfacial alloy layer adheres to the zinc surface, regulating the local current distribution and ion current at the zinc metal anode / electrolyte interface. The formed alloy layer can directionally control the deposition path of zinc, causing zinc to deposit along a fixed crystal plane direction, thereby achieving uniform zinc deposition at high current densities.

[0010] Furthermore, the solvent in the metal halide solution is selected from at least one of common aprotic polar organic solvents such as N'N-dimethylformamide (DMF), N'N-dimethylacetamide, ethylene glycol dimethyl ether (DME), trimethyl phosphate, triethyl phosphate, N'N-dimethylpyrrolidone (NMP), ethanol, and acetone.

[0011] Furthermore, the concentration of the metal halide solution is 0.001–1 mol·L⁻¹. -1 .

[0012] Furthermore, the zinc salt is selected from one or more of the following: zinc trifluoromethanesulfonate (Zn(CF3SO3)2), zinc chloride (ZnCl2), zinc nitrate (Zn(NO3)2), zinc sulfate (ZnSO4), zinc tetrafluoroborate (Zn(BF4)2), zinc perchlorate (Zn(ClO4)2), zinc trifluoromethanesulfonate (Zn(OTf)2), zinc trifluoroacetate (Zn(TFA)2), zinc bis(trifluoromethanesulfonate)imide (Zn(TFSI)2), and zinc bis(fluorosulfonylimide) (Zn(FSI)2).

[0013] Furthermore, the metal ion additive is selected from one or more combinations of metal halides such as zinc fluoride (ZnF2), calcium fluoride (CaF2), antimony fluoride (SbF3), lead fluoride (PbF2), tin fluoride (SnF2), magnesium fluoride (MgF2), antimony chloride (SbCl3), and tin chloride (SnCl2).

[0014] Furthermore, the organic solvent with a boiling point exceeding 100 degrees Celsius is selected from one or more of the following: trimethyl phosphate (TMP), triethyl phosphate (TEP), N,N-dimethylformamide (DMF), N-methylformamide (NMF), N-methylpyrrolidone (NMP), dimethylacetamide (DMAC), dimethyl sulfoxide (DMSO), diethylene glycol dimethyl ether (DEGDME), diethylene glycol diethyl ether (DEGDEE), dipropylene glycol dimethyl ether (DPGDME), butyl acetate, ethyl butyrate, butyl butyrate, propylene glycol methyl ether acetate, 3-methoxybutyl acetate, 2-ethoxyethyl acetate, methyl acetoacetate, and ethyl acetoacetate.

[0015] Furthermore, the concentration of the metal ion additive in the electrolyte is 0.001-0.25 mol / L. -1 .

[0016] Furthermore, the concentration of zinc salt in the electrolyte is 0.1-2.5 mol / L. -1 .

[0017] In a second aspect, the present invention provides a method for improving the coulombic efficiency and stable long-cycle performance of a zinc anode, constructing a secondary zinc-ion battery as described above, and directly cycling the zinc anode in the electrolyte, or first modifying the surface with a metal halide solution before cycling in the electrolyte.

[0018] This invention constructs an alloy modification layer on the surface of metallic zinc and introduces metal ion additives into the electrolyte, the two working synergistically to enhance the Zn content. 2+ Uniform deposition. The core lies in utilizing the reaction of transition metal halides with Zn to form an alloy that regulates the nucleation and growth of Zn during deposition. This transforms the three-dimensional dendritic growth mode of the Zn anode in the thermodynamically stable organic electrolyte into a two-dimensional planar dendrite-free growth mode, achieving stable cycling with high coulombic efficiency of the Zn anode under high current conditions in the organic electrolyte. At the same time, it effectively solves the two key coupling problems of dendrites and interfacial side reactions in the Zn anode.

[0019] The surface modifier used in this invention can form an ion / electron hybrid conductive layer on the surface of the zinc anode. Simultaneously, the electrolyte additive can specifically eliminate zinc dendrites caused by uneven deposition and regulate the zinc ion deposition morphology. The artificially modified layer and the anode / electrolyte interface layer formed after cycling are rich in components and have multiple effects. They can effectively improve the zinc anode interface, suppress interfacial side reactions, and regulate the local current distribution and zinc ion flow distribution near the tip of the zinc metal anode, thereby achieving uniform zinc deposition at higher current densities. Furthermore, the additives in the electrolyte can promote the directional deposition of zinc ions on the alloy surface of the anode, forming a smooth zinc deposition texture. Finally, the artificially modified layer makes the SEI formed at the anode interface more stable, improving the coulombic efficiency of the metal anode. This synergistic strategy enables the zinc anode to achieve high current (50 and 100 mA cm⁻¹) deposition. -2 Under certain conditions, it achieves dendrite-free, high coulombic efficiency, stable long-cycle operation.

[0020] Compared to the physical isolation effect of alloy layers in existing aqueous electrolytes, the surface modification, electrolyte additives, and electrolyte modification strategies of this invention work synergistically to effectively address the two key coupling issues of dendrite formation and interfacial side reactions in the Zn anode. This significantly improves the stability of the zinc anode in secondary zinc-ion batteries, especially enabling dendrite-free, stable, long-cycle operation under high current. The method is simple, easy to implement, and has great application potential. Furthermore, the use of organic solvents with boiling points exceeding 100°C (at normal pressure) greatly enhances battery safety. Attached Figure Description

[0021] Figure 1 The X-ray diffraction spectrum is the result of surface treatment of zinc metal with the surface modifier in Example 1.

[0022] Figure 2 The contact angle test was performed on surface-modified zinc and unmodified zinc in Example 2.

[0023] Figure 3 This is the deposition and dissolution curve of the zinc-assembled symmetrical battery obtained in Example 3.

[0024] Figure 4 This is the deposition and dissolution curve of the zinc-assembled symmetrical battery obtained in Example 4.

[0025] Figure 5 The morphology of the zinc negative electrode obtained in Example 5 is shown.

[0026] Figure 6 The image shows the deposition and dissolution curve of the zinc-assembled symmetrical battery obtained in Example 6.

[0027] Figure 7 The image shows the deposition and dissolution curve of the zinc-assembled symmetrical battery obtained in Example 7.

[0028] Figure 8 This is the deposition and dissolution curve of the zinc-assembled symmetrical battery obtained in Example 8.

[0029] Figure 9 This is an analysis of the fluorine composition on the zinc anode surface obtained in Example 9.

[0030] Figure 10 This is the average coulombic efficiency of the zinc anode obtained in Example 10.

[0031] Figure 11 The morphology of the zinc negative electrode obtained in Example 11 is shown.

[0032] Figure 12 The morphology of the zinc negative electrode obtained in Example 12 is shown. Detailed Implementation

[0033] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0034] In the following embodiments, unless otherwise specified, the raw materials or processing techniques are conventional commercially available raw materials or conventional processing techniques in the art.

[0035] Example 1

[0036] A certain amount of antimony trifluoride was weighed and dissolved in dimethyl ethylene glycol (DME) to a concentration of 0.01 mol / L. -1 It was dropped onto the surface of the zinc anode (the amount added was 20 μL cm). -2 After the solvent has completely evaporated, the surface-modified zinc anode is obtained as follows: Figure 1 As shown.

[0037] X-ray diffraction analysis was performed on the surface-modified zinc anode, such as... Figure 1 As shown, in addition to the standard diffraction peaks of metallic zinc, new diffraction peaks also appear, indicating that new substances are formed on the surface of the zinc anode after surface treatment. This modification layer is beneficial to improving the electrochemical properties of the zinc anode.

[0038] Example 2

[0039] A certain amount of antimony trifluoride was weighed and dissolved in N,N-dimethylformamide (DMF) to a concentration of 0.05 mol / L. -1 Continue adding Zn(CF3SO3)2 to the mixed solvent to obtain a 0.5M Zn(CF3SO3)2 / 0.05M SbF3 / DMF electrolyte (i.e., the concentration of Zn(CF3SO3)2 in the electrolyte is 0.5 mol / L). -1 The concentration of SbF3 was 0.05 mol / L.-1 It was dropped onto the surface of the zinc negative electrode after surface treatment in Example 1, and the contact angle was tested. The results are as follows. Figure 2 As shown, compared to the contact angle of the 0.5M Zn(CF3SO3)2 / DMF electrolyte on the unmodified zinc anode, the 0.5M Zn(CF3SO3)2 / SbF3 / DMF electrolyte exhibits a smaller contact angle, indicating that surface modification can effectively increase the anode wettability of the electrolyte.

[0040] Example 3

[0041] A zinc symmetrical button cell was assembled using 0.5M Zn(CF3SO3)2 / DMF as the electrolyte, a 20-micron-thick porous polyethylene membrane as the separator, and a zinc disc with a diameter of 12 mm as the negative electrode.

[0042] Deposition / stripping cycles were performed at 25°C with a current density of 5 mA and an areal capacity of 5 mAh. Figure 3 As shown, the symmetrical cell short-circuited after 276 hours, indicating poor compatibility of ordinary DMF-based electrolytes with unmodified zinc metal anodes.

[0043] Example 4

[0044] Using the 0.5M Zn(CF3SO3)2 / 0.05M SbF3 / DMF prepared in Example 2 as the electrolyte, a 20-micron-thick porous polyethylene membrane as the separator, and a zinc disc with a diameter of 12 mm as the negative electrode, the zinc negative electrode was surface-modified with SbF3 / DME solution (i.e., the zinc negative electrode after surface modification in Example 1) to assemble a zinc symmetrical coin cell.

[0045] Deposition / stripping cycles were performed at 25°C with a current density of 5 mA and an areal capacity of 5 mAh. Figure 4 As shown, the symmetrical cell maintained a stable voltage curve for 2750 hours, indicating that surface modification and electrolyte additives can effectively improve the zinc anode interface and achieve stable long-term cycling of the zinc anode.

[0046] Example 5

[0047] The electrodes of symmetrical batteries using the 0.5M Zn(CF3SO3)2 / SbF3 / DMF electrolyte prepared in Example 2 + surface-modified zinc anode obtained in Example 1, and the 0.5M Zn(CF3SO3)2 / DMF electrolyte + unmodified zinc anode were characterized by scanning electron microscopy after cycling. The cycling current density was 10 mA and the areal capacity was 10 mAh. The zinc deposition morphology was observed, such as... Figure 5 As shown.

[0048] The zinc metal anode using 0.5M Zn(CF3SO3)2 / DMF electrolyte without surface modification exhibits a loose morphology. In contrast, the zinc anode using 0.5M Zn(CF3SO3)2 / SbF3 / DMF electrolyte with surface modification exhibits a hexagonal blocky zinc deposition morphology with uniform hexagonal particle size.

[0049] Example 6

[0050] Using 0.5M Zn(TFSI)2 / 0.01M SbCl3 / DMF as the electrolyte, a 20-micron-thick porous polyethylene membrane as the separator, and a 12-mm-diameter zinc disc as the negative electrode, the zinc negative electrode was surface-modified with SbCl3 / DME solution according to the method in Example 1 to assemble a zinc symmetrical coin cell.

[0051] High-current deposition / stripping cycling was performed at 25°C with a current density of 10 mA and an areal capacity of 10 mAh. Figure 6 As shown, the symmetrical cell maintained a stable voltage curve over 900 hours, and the voltage polarization remained consistent in the later stages of cycling without significant changes.

[0052] Example 7

[0053] Using 0.5M Zn(TFSI)2 / 0.1M SnF2 / NMP as the electrolyte, a 20-micron-thick porous polyethylene membrane as the separator, and a 12-mm-diameter zinc disc as the negative electrode, the zinc negative electrode was surface-modified with SnF2 / DME solution according to the method in Example 1 to assemble a zinc symmetrical coin cell.

[0054] High-current deposition / stripping cycling was performed at 25°C with a current density of 10 mA and an areal capacity of 10 mAh. Figure 7 As shown, the symmetrical cell maintained a stable voltage curve for 900 hours, indicating that surface modification and electrolyte additives can effectively improve the zinc anode interface and achieve stable long-term cycling of the zinc anode.

[0055] Example 8

[0056] Using 0.5M Zn(CF3SO3)2 / 0.05M SbF3 / DMF as the electrolyte, a 20-micron-thick porous polyethylene membrane as the separator, and a 12-mm-diameter zinc disc as the negative electrode, the zinc negative electrode was surface-modified with SbF3 / DME solution according to the method in Example 1 to assemble a zinc symmetrical coin cell.

[0057] High-current deposition / stripping cycling was performed at 25°C with a current density of 100 mA and an areal capacity of 100 mAh. Figure 8 As shown, the symmetrical battery exhibits stable cycling for over 2400 hours, demonstrating extremely strong high current handling capability.

[0058] Example 9

[0059] Using 0.5M Zn(CF3SO3)2 / 0.05M SbF3 / DMF as the electrolyte, a 20-micron-thick porous polyethylene membrane as the separator, and a 12-mm-diameter zinc disc as the negative electrode, the zinc negative electrode was surface-modified with SnF2 / DME solution according to the method in Example 1 to assemble a zinc symmetric coin cell. High-current deposition / stripping cycling was performed at 25°C with a current density of 10 mA, resulting in an areal capacity of 10 mAh.

[0060] Surface composition analysis was performed on the zinc anode of the symmetrical battery after cycling, such as... Figure 9 As shown, a Zn-F-rich interface layer is formed on the surface of the zinc anode, which is beneficial for the uniform deposition of zinc.

[0061] Example 10

[0062] A zinc-stainless steel half-cell was assembled using 0.5 M Zn(CF3SO3)2 / SbF3 / DMF as the electrolyte, a 20 μm thick porous polyethylene membrane as the separator, and a 12 mm diameter zinc disc as the negative electrode. The zinc negative electrode was surface-modified with SbF3 / DME solution according to the method in Example 1. The coulombic efficiency of the zinc negative electrode was measured. Zinc deposition / stripping cycling was performed at 25 °C with a current density of 2 mA, and the areal capacity was 1 mAh.

[0063] Zinc-stainless steel half-cell deposition-stripping curves are as follows: Figure 10 As shown, the coulombic efficiency of the zinc anode reached 99.89%.

[0064] Example 11

[0065] This embodiment is basically the same as Embodiment 4, except that in this embodiment, the metal halide in the surface modifier is PbF2 (0.05M), and its deposition morphology is as follows. Figure 11 As shown.

[0066] Example 12

[0067] This embodiment is basically the same as Embodiment 4, except that in this embodiment, the metal halide in the surface modifier is CrF3 (0.001M), and its deposition morphology is as follows. Figure 12 As shown.

[0068] Comparative Example 1:

[0069] Compared to Example 4, most aspects are the same, namely, the electrolyte is also 0.5M Zn(CF3SO3)2 / 0.05MSbF3 / DMF, but the zinc anode is not surface-modified. Zinc symmetrical coin cells are then assembled.

[0070] High-current deposition / stripping cycling was performed at 25°C with a current density of 5 mA and an areal capacity of 5 mAh. The symmetric cell could only meet the standard of stable cycling for more than 1200 hours. However, after 1200 hours, the overpotential of the symmetric cell decreased abruptly, and a short circuit occurred inside the cell. This was because of the lack of zinc anode surface treatment, resulting in uneven current distribution and uneven zinc deposition on the zinc anode surface.

[0071] Comparative Example 2

[0072] Compared to Example 4, most aspects are the same, namely, the same surface-modified zinc anode is used; however, the electrolyte is 0.5M Zn(CF3SO3)2 / DMF. Zinc symmetric coin cells are then assembled.

[0073] High-current deposition / stripping cycling was performed at 25°C with a current density of 5 mA and an areal capacity of 5 mAh. The symmetric cell exhibited stable cycling for over 1100 hours. However, after 1100 hours, the overpotential abrupt change in the symmetric cell decreased, and a short circuit occurred within the cell. This was because the lack of metal ion additives prevented complete control over the zinc morphology deposited on the zinc anode surface, ultimately leading to zinc dendrites piercing the separator and causing a short circuit.

[0074] By comparing Examples 3 and 4, and Comparative Examples 1 and 2, it can be found that zinc anode surface modification and electrolyte additives both significantly improve battery life, and the effect is most obvious when the two work synergistically. Therefore, it is necessary to achieve high coulombic efficiency of zinc anode in zinc-ion batteries through the synergistic effect of zinc anode surface modification and electrolyte additives.

[0075] Example 13

[0076] This embodiment is basically the same as embodiment 4, except that in this embodiment, the metal halide in the surface modifier is MgF2 (0.05M).

[0077] Example 14

[0078] This embodiment is basically the same as embodiment 4, except that in this embodiment, the metal halide of the electrolyte additive is PbF2.

[0079] Example 15

[0080] This embodiment is basically the same as embodiment 4, except that in this embodiment, the metal halide of the electrolyte additive is SnF2.

[0081] Example 16

[0082] This embodiment is basically the same as embodiment 4, except that the electrolyte solvent in this embodiment is TMP.

[0083] Example 17

[0084] This embodiment is basically the same as embodiment 4, except that in this embodiment, the electrolyte solvent is DMAC.

[0085] Example 18

[0086] This embodiment is basically the same as embodiment 7, except that in this embodiment, the zinc salt in the electrolyte is Zn(TFA)2.

[0087] Example 19

[0088] This embodiment is basically the same as embodiment 7, except that in this embodiment, the zinc salt in the electrolyte is Zn(FSI)2.

[0089] In summary, the zinc anode and electrolyte designed in this invention can deposit a special hexagonal block morphology under high current conditions, achieving stable dendrite-free, high coulombic efficiency long-term cycling. Compared with other zinc anode modification strategies, this method is simple, feasible, and has great application potential.

[0090] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A secondary zinc-ion battery, comprising a zinc negative electrode, a positive electrode, and an electrolyte, characterized in that, The electrolyte contains zinc salt, metal ion additives, and organic solvents with a boiling point exceeding 100°C.

2. A secondary zinc-ion battery according to claim 1, characterized in that, The zinc anode is further surface-modified with a metal halide solution, wherein the solute in the metal halide solution is selected from one or more combinations of calcium fluoride, antimony fluoride, lead fluoride, tin fluoride, magnesium fluoride, chromium fluoride, antimony chloride, tin chloride, and chromium chloride.

3. A secondary zinc-ion battery according to claim 2, characterized in that, The solvent in the metal halide solution is selected from at least one of N-methylformamide, N'N-dimethylformamide, N'N-dimethylacetamide, ethylene glycol dimethyl ether, trimethyl phosphate, triethyl phosphate, N'N-dimethylpyrrolidone, tetrahydrofuran, ethanol, and acetone.

4. A secondary zinc-ion battery according to claim 2, characterized in that, The concentration of the metal halide solution is 0.001–1 mol·L⁻¹. -1 .

5. A secondary zinc-ion battery according to claim 1, characterized in that, The zinc salt is selected from one or more of zinc trifluoromethanesulfonate, zinc chloride, zinc nitrate, zinc sulfate, zinc tetrafluoroborate, zinc perchlorate, zinc trifluoromethanesulfonate, zinc trifluoroacetate, zinc bis(trifluoromethanesulfonate)imide, and zinc bis(fluorosulfonyl)imide.

6. A secondary zinc-ion battery according to claim 1, characterized in that, The metal ion additive is selected from one or more combinations of zinc fluoride, calcium fluoride, antimony fluoride, lead fluoride, tin fluoride, magnesium fluoride, chromium fluoride, antimony chloride, tin chloride, and chromium chloride.

7. A secondary zinc-ion battery according to claim 1, characterized in that, The organic solvent with a boiling point exceeding 100 degrees Celsius is selected from one or more of the following: trimethyl phosphate, triethyl phosphate, N,N-dimethylformamide, N-methylformamide, N-methylpyrrolidone, dimethylacetamide, dimethyl sulfoxide, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, dipropylene glycol dimethyl ether, butyl acetate, ethyl butyrate, butyl butyrate, propylene glycol methyl ether acetate, 3-methoxybutyl acetate, 2-ethoxyethyl acetate, methyl acetoacetate, and ethyl acetoacetate.

8. A secondary zinc-ion battery according to claim 1, characterized in that, The concentration of the metal ion additive in the electrolyte is 0.001-0.25 mol / L. -1 .

9. A secondary zinc-ion battery according to claim 1, characterized in that, The concentration of zinc salt in the electrolyte is 0.1-2.5 mol / L. -1 .

10. A method for improving the coulombic efficiency and stable long-cycle performance of a zinc anode, characterized in that, To construct a secondary zinc-ion battery as described in any one of claims 1-9, the zinc negative electrode is directly circulated in the electrolyte, or the surface is first modified with a metal halide solution before being circulated in the electrolyte.

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