Water-based zinc ion battery zinc negative electrode based on composite additive and preparation method and application of water-based zinc ion battery zinc negative electrode

Abstract

The invention provides an aqueous zinc ion battery zinc negative electrode based on a composite additive and a preparation method and application thereof, and belongs to the technical field of aqueous zinc ion batteries. In order to solve the problems of dendritic crystal growth and the like of a zinc negative electrode in an aqueous zinc ion battery, a composite additive comprising dimethyl sulfoxide, 1-methyl-2-pyrrolidone and formamide is introduced into an electroplating solution, zinc is induced to preferentially grow along a (002) crystal face, and a compact dendritic-crystal-free deposition layer is formed to serve as the zinc negative electrode. The zinc negative electrode has good reversibility, the water-based zinc ion battery assembled based on the zinc negative electrode has good cycling stability and relatively low polarization voltage, and an effective scheme is provided for solving the problem of negative electrode dendritic crystals of the water-based zinc ion battery.

Description

Technical Field

[0001] This invention relates to the field of aqueous zinc-ion battery technology, specifically to a zinc anode for aqueous zinc-ion batteries based on composite additives, its preparation method, and its application. Background Technology

[0002] With the accelerated transformation of the global energy structure, the unsustainability of traditional fossil fuels is becoming increasingly prominent, urgently requiring the development of efficient and environmentally friendly new energy storage technologies. Among various energy storage solutions, lithium-ion batteries dominate, but face the dual constraints of thermal runaway risk and lithium resource shortages. Aqueous zinc-ion batteries, with their inherent safety, abundant resources, and environmental friendliness, have become a promising next-generation energy storage technology.

[0003] Zinc metal anodes exhibit unique advantages among various anode materials due to their high theoretical specific capacity of 820 mAh / g, moderate redox potential (-0.76 V relative to the standard hydrogen electrode), and excellent processing performance. However, the safety hazards of traditional organic electrolyte systems, such as flammability and explosiveness, severely restrict the commercialization of zinc-ion batteries. In contrast, zinc-ion batteries (AZIBs) using aqueous electrolytes not only fundamentally solve the safety problem but also have significant advantages such as low cost and environmental friendliness, making them a research hotspot in the energy storage field.

[0004] In practical applications of AZIBs, zinc anodes still face a significant challenge in dendrite growth. This phenomenon stems from the "sharp effect" during zinc deposition. During electrochemical deposition, zinc ions tend to preferentially deposit on protruding sites on the electrode surface, leading to increased local current density and accelerating dendrite formation and growth. These continuously growing zinc dendrites can not only penetrate the separator and cause internal short circuits but also result in irreversible loss of active materials, ultimately leading to a sharp decline in battery cycle performance and a continuous decrease in coulombic efficiency.

[0005] Therefore, there is an urgent need to develop a low-cost, high-efficiency, and easily industrialized zinc anode suitable for aqueous zinc-ion batteries. Summary of the Invention

[0006] To address the shortcomings of the existing technologies, this invention provides a zinc anode for an aqueous zinc-ion battery based on composite additives, its preparation method, and its application, thereby solving problems such as uncontrolled dendrite growth and severe side reactions in existing aqueous zinc-ion batteries.

[0007] To achieve the above objectives, the specific technical solution of the present invention is as follows:

[0008] In a first aspect, the present invention provides a method for preparing a zinc anode for an aqueous zinc-ion battery, comprising the following steps: inserting zinc sheet / zinc foil and a metal substrate into an electroplating solution containing zinc salt, sodium salt and composite additives, and applying electricity to electroplat and deposit metallic zinc on the surface of the metal substrate to obtain a zinc anode; wherein the composite additives include dimethyl sulfoxide (DMSO), 1-methyl-2-pyrrolidone (NMP) and formamide (FA).

[0009] This invention introduces specific composite organic functional additives, including dimethyl sulfoxide, 1-methyl-2-pyrrolidone, and formamide, into an aqueous electroplating solution; wherein, dimethyl sulfoxide reconstructs Zn through its strong polar properties. 2+ The solvation of the sheath significantly reduces the desolvation energy barrier; 1-methyl-2-pyrrolidone optimizes the double-layer structure at the electrode interface and suppresses side reactions; formamide stabilizes the chemical environment of the electroplating solution through a hydrogen bond network. This composite multi-component synergistic mechanism effectively guides uniform zinc deposition, fundamentally inhibiting dendrite formation and improving battery cycle stability and lifespan. This invention focuses on the regulatory mechanism of composite organic functional additives on zinc electrochemical deposition behavior, systematically exploring the synergistic mechanism of composite additives including dimethyl sulfoxide, 1-methyl-2-pyrrolidone, and formamide in the electrolyte, and using XRD (X-ray diffraction) and SEM (scanning electron microscopy) to reveal the interaction between the composite additive molecules and Zn. 2+ Based on the specific coordination behavior of the zinc anode and its role in reconstructing the solvation structure, this invention provides a method for preparing a zinc anode for an aqueous zinc-ion battery, and uses the zinc anode to assemble an aqueous zinc-ion battery with long cycle stability, low coulombic efficiency decay, and no dendrites on the surface after charge-discharge cycles.

[0010] Furthermore, the concentration of zinc salt in the electroplating solution is 0.1~0.5 M, and the concentration of sodium salt is 0.1~0.5 M.

[0011] Furthermore, the zinc salt includes, but is not limited to, zinc sulfate, and the sodium salt includes, but is not limited to, sodium sulfate.

[0012] Further, the concentration of the composite additive in the electroplating solution is 0.2~0.8 g / L. In one example of the present invention, the concentration of the additive is 0.6 g / L.

[0013] Further, the volume ratio of the dimethyl sulfoxide, 1-methyl-2-pyrrolidone, and formamide is (0.5~2):1:(1~3). In one example of the present invention, the volume ratio of the dimethyl sulfoxide, 1-methyl-2-pyrrolidone, and formamide is 1:1:1.

[0014] Furthermore, the pH value of the electroplating solution is 3.0~6.5.

[0015] Furthermore, the current intensity is 2~15 mA / cm. 2 The power-on time shall not be less than 40 minutes.

[0016] Secondly, the present invention provides a zinc anode for an aqueous zinc-ion battery prepared by the method described above.

[0017] Thirdly, the present invention provides the application of the zinc anode in the preparation of aqueous zinc-ion batteries.

[0018] Fourthly, the present invention provides an aqueous zinc-ion battery, including the zinc negative electrode.

[0019] Furthermore, the aqueous zinc-ion battery also includes a positive electrode and a separator, and an electrolyte is filled between the zinc negative electrode and the positive electrode.

[0020] Furthermore, the aqueous zinc-ion battery includes, but is not limited to, Zn / / Zn symmetric cells, half-cells, or full-cells.

[0021] Furthermore, the positive electrode material of the Zn / / Zn symmetric battery is the same as that of the negative electrode. The assembly method of the Zn / / Zn symmetric battery is as follows: a zinc negative electrode is sequentially placed in the negative electrode shell, a separator (such as a glass fiber separator) is added and electrolyte is added, a positive electrode sheet is placed (the positive electrode material of the symmetric battery is the same as that of the negative electrode, that is, the zinc negative electrode is used as the positive electrode sheet), a 304 stainless steel gasket and a spring are placed in, and the positive electrode shell is added and then sealed.

[0022] Furthermore, the positive electrode material of the half-cell includes, but is not limited to, copper foil (Cu). The assembly method of the half-cell is as follows: zinc negative electrode sheet is sequentially placed in the negative electrode shell, a separator (such as a glass fiber separator) is added and electrolyte is added, copper sheet is placed as positive electrode sheet, 304 stainless steel gasket and spring are placed in, and the positive electrode shell is added and then sealed.

[0023] Furthermore, the positive electrode material of the full cell includes, but is not limited to, cobalt-based oxides, nickel-based oxides, and (NH4). x The assembly method for VO3, Prussian blue analogues, and full cells is as follows: install the zinc negative electrode in the negative electrode shell, add the separator (such as a glass fiber separator) and drop the electrolyte, add the positive electrode material, then add the gasket and spring, and finally seal it after adding the positive electrode shell.

[0024] Compared with the prior art, the advantages of the present invention are:

[0025] (1) Synergistic Regulation Mechanism of Composite Functional Additives: This invention innovatively employs a composite system comprising dimethyl sulfoxide, 1-methyl-2-pyrrolidone, and formamide to significantly optimize zinc deposition behavior through the synergistic effect of multiple components. Among them, dimethyl sulfoxide reconstructs Zn through its strong polarity. 2+ The solvation sheath lowers the desolvation energy barrier (approximately 40% lower than traditional single-additive systems); 1-methyl-2-pyrrolidone optimizes the electrode / electrolyte interface double-layer structure, suppressing side reactions such as hydrogen evolution (reducing side reaction current density by 60%); formamide stabilizes the electrolyte pH through a hydrogen bond network (reducing pH fluctuation range from ±1.5 to ±0.3). The synergistic effect of multiple components in the composite additive, including dimethyl sulfoxide, 1-methyl-2-pyrrolidone, and formamide, reduces the zinc deposition overpotential to below 60 mV, significantly superior to single-additive systems or conventional zinc anodes (>60 mV).

[0026] (2) Dendrite suppression and improved cycle stability: The composite additives of this invention induce zinc to preferentially grow along the (002) crystal plane, forming a dense dendrite-free deposition layer (dendrite density reduced by 90%). The symmetrical cell assembled with the zinc anode of this invention achieves a cycle stability of 5 mA / cm². 2 It achieves long-term cycling stability of over 240 hours at current density, which is significantly higher than that of zinc anodes lacking a certain additive, and the polarization voltage is stable at around 60 mV, which is much lower than the 120 mV of the traditional system (without additives).

[0027] (3) Interface stability and coulombic efficiency optimization: The coulombic efficiency of the half-cell assembled in this invention remains high after 400 cycles, and there are no dendrites or corrosion pits on the electrode surface after cycling. The initial capacity of the assembled full cell reaches 230 mAh / g, and the capacity retention rate is 65% after 100 cycles, which is better than the results reported in the same category (usually <60%). Attached Figure Description

[0028] Figure 1 A schematic diagram of the process flow for zinc anode A-Cu@Zn;

[0029] Figure 2 Images of copper foil, A-Cu@Zn, M-Cu@Zn, N-Cu@Zn, and O-Cu@Zn.

[0030] Figure 3 In Figure 'a', the X-ray diffraction patterns of the copper foil and zinc foil are shown. Figure 3 In the diagram, b represents the X-ray diffraction pattern of A-Cu@Zn, M-Cu@Zn, N-Cu@Zn, and O-Cu@Zn;

[0031] Figure 4SEM characterization images of zinc anodes A-Cu@Zn (a), M-Cu@Zn (b), N-Cu@Zn (c), and O-Cu@Zn (d);

[0032] Figure 5 The constant current charge-discharge test results are for A-Cu@Zn symmetrical cells, M-Cu@Zn symmetrical cells, N-Cu@Zn symmetrical cells, and O-Cu@Zn symmetrical cells; among them, Figure 5 a represents the cycle performance test results of A-Cu@Zn symmetric cells, M-Cu@Zn symmetric cells, N-Cu@Zn symmetric cells, and O-Cu@Zn symmetric cells; Figure 5 b is a voltage magnification diagram after 8-10 hours of cycling; Figure 5 c is a voltage magnification diagram after 228-230 hours of cycling; Figure 5 d represents the charge-discharge curves of an A-Cu@Zn symmetrical battery with different numbers of cycles; Figure 5 e represents the charge-discharge curves of an O-Cu@Zn symmetrical battery with different numbers of cycles; Figure 5 f represents the charge-discharge curves of an N-Cu@Zn symmetrical battery with different numbers of cycles; Figure 5 g represents the charge-discharge curves of an M-Cu@Zn symmetrical battery with different numbers of cycles;

[0033] Figure 6 The constant current charge-discharge test results are for A-Cu@Zn / / Cu half-cells, M-Cu@Zn / / Cu half-cells, N-Cu@Zn / / Cu half-cells, and O-Cu@Zn / / Cu half-cells; among them, Figure 6 a represents the cycle performance test results of the A-Cu@Zn / / Cu half-cell, M-Cu@Zn / / Cu half-cell, N-Cu@Zn / / Cu half-cell, and O-Cu@Zn / / Cu half-cell; Figure 6 b represents the charge-discharge curves of the A-Cu@Zn / / Cu half-cell at different cycles; Figure 6 c represents the charge-discharge curves of the M-Cu@Zn / / Cu half-cell at different cycles; Figure 6 d represents the charge-discharge curves of the N-Cu@Zn / / Cu half-cell at different numbers of cycles; Figure 6 e represents the charge-discharge curves of the O-Cu@Zn / / Cu half-cell at different cycles;

[0034] Figure 7 For A-Cu@Zn / / (NH4) x VO3 full cell, M-Cu@Zn / / (NH4) x VO3 full cell, N-Cu@Zn / / (NH4) x VO3 full cell and O-Cu@Zn / / (NH4) x Constant current charge-discharge test results of VO3 full battery; among which, Figure 7a represents A-Cu@Zn / / (NH4) x VO3 full cell, M-Cu@Zn / / (NH4) x VO3 full cell, N-Cu@Zn / / (NH4) x VO3 full cell and O-Cu@Zn / / (NH4) x Cyclic performance test results of VO3 full batteries; Figure 7 b represents A-Cu@Zn / / (NH4) x Charge-discharge curves of VO3 full battery at different charge / discharge cycles; Figure 7 c represents M-Cu@Zn / / (NH4) x Charge-discharge curves of VO3 full battery at different charge / discharge cycles; Figure 7 d represents N-Cu@Zn / / (NH4) x Charge-discharge curves of VO3 full battery at different charge / discharge cycles; Figure 7 e represents O-Cu@Zn / / (NH4) x Charge-discharge curves of VO3 full battery at different charge / discharge cycles;

[0035] Figure 8 For A-Cu@Zn / / (NH4) x CV test results of VO3 full cells;

[0036] Figure 9 In the figure, 'a' represents the measurement of three A-Cu@Zn / / (NH4) atoms using a multimeter. x Voltage diagram of a full VO3 cell in series; Figure 9 In the given equation, b represents three A-Cu@Zn / / (NH4). x Diagram showing VO3 batteries connected in series to illuminate an LED light. Detailed Implementation

[0037] The technical solution of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] This invention provides a method for preparing a zinc anode for an aqueous zinc-ion battery, comprising the following steps: inserting zinc sheet / zinc foil and a metal substrate (e.g., copper) into an electroplating solution containing zinc salt, sodium salt and composite additives, and applying electricity to electroplat and deposit metallic zinc on the surface of the metal substrate to obtain a zinc anode; wherein the composite additives include dimethyl sulfoxide (DMSO), 1-methyl-2-pyrrolidone (NMP) and formamide (FA).

[0039] In some examples, the concentration of zinc salt in the electroplating solution is 0.1~0.5 M, the concentration of sodium salt is 0.1~0.5 M, and the concentration of composite additive is 0.2~0.8 g / L.

[0040] In some examples, the volume ratio of the dimethyl sulfoxide, 1-methyl-2-pyrrolidone and formamide is (0.5~2):1:(1~3).

[0041] In some examples, the pH value of the electroplating solution is 3.0 to 6.5, for example, the pH value can be 3.0, 4.5, 5.0 or 6.5.

[0042] In some examples, the current intensity is 2~15 mA / cm. 2 For example, the current density could be 2 mA / cm². 2 5 mA / cm 2 10 mA / cm 2 Or 15 mA / cm 2 The energizing time shall not be less than 40 minutes. For example, the energizing time may be 40 minutes, 50 minutes, 60 minutes, 80 minutes or 90 minutes.

[0043] In the following specific embodiments, unless otherwise specified, the (NH4) used is... x The preparation methods of VO3 cathode material and cathode sheet are as follows:

[0044] (1) Precursor synthesis: Dissolve NH4VO3 (1.0 g) in aqueous solution (250 mL) at 75 °C, add thiourea (10 mmol), adjust pH to < 2.0 with sulfuric acid, react at 90 °C for 2.5 h, and obtain the reaction product after cooling.

[0045] (2) Purification: The reaction product was filtered, washed with water / ethanol alternately (5 times), and dried under vacuum at 60℃ for 12 h to obtain (NH4). x VO3 cathode material powder.

[0046] (3) Electrode preparation: (NH4) x VO3 cathode material powder was mixed with acetylene black (conductive agent) and PVDF (binder) at a mass ratio of 7:2:1. 1-Methyl-2-pyrrolidone (NMP) (4 mL) was added and the mixture was ground for 40 min to form a uniform slurry.

[0047] 4) Electrode processing: The slurry is coated onto carbon paper and dried at 80℃ for 6 h. It is then stamped into a positive electrode sheet with a diameter of 12 mm. The formula for calculating the active material loading is: Loading = (mass after coating – average mass of blank carbon paper) × 0.7.

[0048] Example 1

[0049] An aqueous zinc-ion battery is prepared as follows:

[0050] 1. Preparation of electroplating solution

[0051] (1) Add 5.75 g ZnSO4·7H2O (0.02 mol) and 2.84 g Na2SO4 (0.02 mol) to 80 mL of deionized water and stir with a magnetic stirrer until completely dissolved to obtain a mixed solution; the concentration of ZnSO4 in the mixed solution is 0.25 M and the concentration of Na2SO4 is 0.25 M.

[0052] (2) Stop the magnetic stirring and let it stand for 10 minutes until the mixed solution is clear before use.

[0053] (3) Measure DMSO, NMP and FA in a volume ratio of 1:1:1 and add them to a 5 mL graduated cylinder. Shake well to obtain the composite additive.

[0054] (4) Weigh 48 mg of the composite additive and add it to the mixed solution in step (2), shake well to obtain an electroplating solution containing the composite additive (denoted as A-electroplating solution); the concentration of the composite additive in the electroplating solution is 0.6 g / L.

[0055] 2. Preparation of zinc negative electrode sheet

[0056] (1) Take a copper foil with a thickness of 0.1 mm, wipe the surface with anhydrous ethanol to remove oxides, and dry it; then use a 12 mm punching machine to press it into a circular electrode sheet; prepare a rectangular zinc foil with a size similar to the copper foil, clean the surfaces of the copper foil and zinc foil with deionized water and dry them for later use.

[0057] (2) Place the A-electroplating solution in a 100 mL beaker, and fix the zinc foil and copper foil parallel to each other on the clamping device of the three-electrode system, ensuring that the electrode spacing (25 mm) is consistent; connect the electrochemical workstation and turn on the power, set the constant current mode, and control the current density to 5 mA / cm. 2 The energizing time is 70 minutes, which allows for the uniform deposition of metallic zinc on the surface of the copper foil.

[0058] (3) The copper foil plated with zinc was immersed in deionized water and ultrasonically cleaned for 2 min to remove residual electroplating solution from the surface. After drying, a zinc negative electrode sheet with a diameter of 12 mm (denoted as A-Cu@Zn) was obtained. The process flow diagram is shown below. Figure 1 As shown.

[0059] 3. Assemble an aqueous zinc-ion battery

[0060] The zinc-ion battery in this embodiment adopts a typical button cell structure, consisting of, from bottom to top, a negative electrode shell, a negative electrode sheet, a separator, a positive electrode sheet, a gasket, a spring, and a positive electrode shell. The negative electrode shell serves as the bottom support, functioning to conduct current and protect internal components. During discharge, the negative electrode sheet undergoes an oxidation reaction, releasing zinc ions and electrons. The porous structure of the separator ensures zinc ion transport while preventing short circuits between the positive and negative electrodes. The positive electrode sheet undergoes a reduction reaction to store energy. The gasket isolates the positive electrode assembly from the shell, preventing edge short circuits. The spring, with its wave-shaped spring design, ensures current conduction while buffering electrode volume changes.

[0061] (1) Zn / / Zn symmetric battery, the positive electrode material is the same as the negative electrode material, and the assembly method is as follows: A-Cu@Zn (smooth side up), separator (glass fiber separator) are added to the negative electrode shell in sequence and ZnSO4 electrolyte is added drop by drop, then A-Cu@Zn (smooth side down) is placed in, a gasket and a spring are added, and then the positive electrode shell is placed on top for encapsulation to obtain A-Cu@Zn symmetric battery.

[0062] (2) Zn / / Cu half cell, with a 12 mm diameter copper foil that has been cleaned and dried with deionized water as the positive electrode, is assembled as follows: A-Cu@Zn (smooth side up), separator (glass fiber separator) are added to the negative electrode shell in sequence, and ZnSO4 electrolyte is added drop by drop. Then, a 12 mm copper foil is added, a gasket and a spring are added, and then the positive electrode shell is placed on top for encapsulation to obtain an A-Cu@Zn / / Cu half cell.

[0063] (3) Zn / / (NH4) x VO3 full cell, with (NH4) x VO3 is the positive electrode material, and the assembly method is as follows: Add A-Cu@Zn (smooth side up), a separator (glass fiber separator) sequentially to the negative electrode shell, and then add ZnSO4 electrolyte, followed by (NH4). x A VO3 positive electrode sheet (active material loading of 2.25 mg) was prepared by adding a gasket and a spring sheet, and then encapsulating it with a positive electrode shell to obtain A-Cu@Zn / / (NH4). x VO3 full battery.

[0064] Example 2

[0065] A zinc anode for an aqueous zinc-ion battery is prepared by the following method:

[0066] 1. Preparation of electroplating solution

[0067] (1) Add 5.75 g ZnSO4·7H2O (0.02 mol) and 2.84 g Na2SO4 (0.02 mol) to 80 mL of deionized water and stir with a magnetic stirrer until completely dissolved to obtain a mixed solution; the concentration of ZnSO4 in the mixed solution is 0.25 M and the concentration of Na2SO4 is 0.25 M.

[0068] (2) Stop the magnetic stirring and let it stand for 20 minutes until the mixed solution is clear before use.

[0069] (3) Measure DMSO, NMP and FA in a volume ratio of 1:1:1 and add them to a 5 mL graduated cylinder. Shake well to obtain the composite additive.

[0070] (4) Weigh 48 mg of the composite additive and add it to the mixed solution in step (2), shake well to obtain an electroplating solution containing the composite additive (denoted as A-electroplating solution); the concentration of the composite additive in the electroplating solution is 0.6 g / L.

[0071] 2. Preparation of zinc negative electrode sheet

[0072] (1) Take a copper foil with a thickness of 0.1 mm, wipe the surface with anhydrous ethanol to remove oxides, and dry it; then use a 12 mm punching machine to press it into a circular electrode sheet; prepare a rectangular zinc foil with a size similar to the copper foil, clean the surfaces of the copper foil and zinc foil with deionized water and dry them for later use.

[0073] (2) Place the A-electroplating solution in a 100 mL beaker, and fix the zinc foil and copper foil parallel to each other on the clamping device of the three-electrode system, ensuring that the electrode spacing (25 mm) is consistent; connect the electrochemical workstation and turn on the power, set the constant current mode, and control the current density to 10 mA / cm. 2 The energizing time is 50 minutes, which allows for the uniform deposition of metallic zinc on the surface of the copper foil.

[0074] (3) Immerse the copper foil plated with metallic zinc in deionized water and ultrasonically clean it for 2 min to remove the residual electroplating solution on the surface. After drying, a zinc negative electrode sheet with a diameter of 12 mm (denoted as B-Cu@Zn) is obtained.

[0075] Example 3

[0076] A zinc anode for an aqueous zinc-ion battery is prepared by the following method:

[0077] 1. Preparation of electroplating solution

[0078] (1) Add 5.75 g ZnSO4·7H2O (0.02 mol) and 2.84 g Na2SO4 (0.02 mol) to 80 mL of deionized water and stir with a magnetic stirrer until completely dissolved to obtain a mixed solution; the concentration of ZnSO4 in the mixed solution is 0.25 M and the concentration of Na2SO4 is 0.25 M.

[0079] (2) Stop the magnetic stirring and let it stand for 15 minutes until the mixed solution is clear before use.

[0080] (3) Measure DMSO, NMP and FA in a volume ratio of 1:1:1 and add them to a 5 mL graduated cylinder. Shake well to obtain the composite additive.

[0081] (4) Weigh 48 mg of the composite additive and add it to the mixed solution in step (2), shake well to obtain an electroplating solution containing the composite additive (denoted as A-electroplating solution); the concentration of the composite additive in the electroplating solution is 0.6 g / L.

[0082] 2. Preparation of zinc negative electrode sheet

[0083] (1) Take a copper foil with a thickness of 0.1 mm, wipe the surface with anhydrous ethanol to remove oxides, and dry it; then use a 12 mm punching machine to press it into a circular electrode sheet; prepare a rectangular zinc foil with a size similar to the copper foil, clean the surfaces of the copper foil and zinc foil with deionized water and dry them for later use.

[0084] (2) Place the A-electroplating solution in a 100 mL beaker, and fix the zinc foil and copper foil parallel to each other on the clamping device of the three-electrode system, ensuring that the electrode spacing (25 mm) is consistent; connect the electrochemical workstation and turn on the power, set the constant current mode, and control the current density to 15 mA / cm. 2 The energizing time is 40 minutes, which allows for the uniform deposition of metallic zinc on the surface of the copper foil.

[0085] (3) Immerse the copper foil plated with metallic zinc in deionized water and ultrasonically clean it for 2 min to remove the residual electroplating solution on the surface. After drying, a zinc negative electrode sheet with a diameter of 12 mm (denoted as C-Cu@Zn) is obtained.

[0086] Comparative Example 1

[0087] An aqueous zinc-ion battery is prepared as follows:

[0088] 1. Preparation of electroplating solution

[0089] (1) Add 5.75 g ZnSO4·7H2O (0.02 mol) and 2.84 g Na2SO4 (0.02 mol) to 80 mL of deionized water and stir with a magnetic stirrer until completely dissolved to obtain a mixed solution; the concentration of ZnSO4 in the mixed solution is 0.25 M and the concentration of Na2SO4 is 0.25 M.

[0090] (2) Stop the magnetic stirring and let it stand for 10 minutes until the mixed solution is clear before use.

[0091] (3) Measure DMSO and NMP in a volume ratio of 1:1 and add them to a 5 mL graduated cylinder. Shake well to obtain the composite additive.

[0092] (4) Weigh 48 mg of the composite additive and add it to the mixed solution in step (2), shake well to obtain an electroplating solution containing the composite additive (denoted as M-electroplating solution); the concentration of the composite additive in the electroplating solution is 0.6 g / L.

[0093] 2. Preparation of zinc negative electrode sheet

[0094] (1) Take a copper foil with a thickness of 0.1 mm, wipe the surface with anhydrous ethanol to remove oxides, and dry it; then use a 12 mm punching machine to press it into a circular electrode sheet; prepare a rectangular zinc foil with a size similar to the copper foil, clean the surfaces of the copper foil and zinc foil with deionized water and dry them for later use.

[0095] (2) Place the M-electroplating solution in a 100 mL beaker, and fix the zinc foil and copper foil parallel to each other on the clamping device of the three-electrode system, ensuring that the electrode spacing (25 mm) is consistent; connect the electrochemical workstation and turn on the power, set the constant current mode, and control the current density to 5 mA / cm. 2 The energizing time is 70 minutes, which allows for the uniform deposition of metallic zinc on the surface of the copper foil.

[0096] (3) Immerse the copper foil plated with metallic zinc in deionized water and ultrasonically clean it for 2 min to remove the residual electroplating solution on the surface. After drying, a zinc negative electrode sheet with a diameter of 12 mm (denoted as M-Cu@Zn) is obtained.

[0097] 3. Assemble an aqueous zinc-ion battery

[0098] The Zn / / Zn symmetric battery uses the same positive and negative electrode materials. The assembly method is as follows: M-Cu@Zn (smooth side up) and a separator (glass fiber separator) are added sequentially to the negative electrode shell, and ZnSO4 electrolyte is added dropwise. Then, M-Cu@Zn (smooth side down) is placed in the shell, and a gasket and spring are added. Finally, the positive electrode shell is placed on top for encapsulation to obtain the M-Cu@Zn symmetric battery.

[0099] Using copper foil as the positive electrode and M-Cu@Zn as the negative electrode, an M-Cu@Zn / / Cu half-cell was assembled; (NH4) x VO3 material is used as the positive electrode, and M-Cu@Zn is used as the negative electrode, resulting in M-Cu@Zn / / (NH4). x VO3 full battery.

[0100] Comparative Example 2

[0101] An aqueous zinc-ion battery is prepared as follows:

[0102] 1. Preparation of electroplating solution

[0103] (1) Add 5.75 g ZnSO4·7H2O (0.02 mol) and 2.84 g Na2SO4 (0.02 mol) to 80 mL of deionized water and stir with a magnetic stirrer until completely dissolved to obtain a mixed solution; the concentration of ZnSO4 in the mixed solution is 0.25 M and the concentration of Na2SO4 is 0.25 M.

[0104] (2) Stop the magnetic stirring and let it stand for 10 minutes until the mixed solution is clear before use.

[0105] (3) Measure DMSO and FA in a volume ratio of 1:1 and add them to a 5 mL graduated cylinder. Shake well to obtain the composite additive.

[0106] (4) Weigh 48 mg of the composite additive and add it to the mixed solution in step (2), shake well to obtain an electroplating solution containing the composite additive (denoted as N-electroplating solution); the concentration of the composite additive in the electroplating solution is 0.6 g / L.

[0107] 2. Preparation of zinc negative electrode sheet

[0108] (1) Take a copper foil with a thickness of 0.1 mm, wipe the surface with anhydrous ethanol to remove oxides, and dry it; then use a 12 mm punching machine to press it into a circular electrode sheet; prepare a rectangular zinc foil with a size similar to the copper foil, clean the surfaces of the copper foil and zinc foil with deionized water and dry them for later use.

[0109] (2) Place the N-electroplating solution in a 100 mL beaker, and fix the zinc foil and copper foil parallel to each other on the clamping device of the three-electrode system, ensuring that the electrode spacing (25 mm) is consistent; connect the electrochemical workstation and turn on the power, set the constant current mode, and control the current density to 5 mA / cm. 2 The energizing time is 70 minutes, which allows for the uniform deposition of metallic zinc on the surface of the copper foil.

[0110] (3) Immerse the copper foil plated with metallic zinc in deionized water and ultrasonically clean it for 2 min to remove the residual electroplating solution on the surface. After drying, a zinc negative electrode sheet with a diameter of 12 mm (denoted as N-Cu@Zn) is obtained.

[0111] 3. Assemble an aqueous zinc-ion battery

[0112] The Zn / / Zn symmetric battery uses the same positive and negative electrode materials. The assembly method is as follows: On the negative electrode shell, N-Cu@Zn (smooth side up), a separator (glass fiber separator) are added in sequence, and ZnSO4 electrolyte is added dropwise. Then, N-Cu@Zn (smooth side down) is placed in, and a gasket and spring are added. Finally, the positive electrode shell is placed on top for encapsulation to obtain the N-Cu@Zn symmetric battery.

[0113] Using copper foil as the positive electrode and N-Cu@Zn as the negative electrode, an N-Cu@Zn / / Cu half-cell was assembled; (NH4) x VO3 material is used as the positive electrode, and N-Cu@Zn is used as the negative electrode, resulting in N-Cu@Zn / / (NH4). x VO3 full battery.

[0114] Comparative Example 3

[0115] An aqueous zinc-ion battery is prepared as follows:

[0116] 1. Preparation of electroplating solution

[0117] (1) Add 5.75 g ZnSO4·7H2O (0.02 mol) and 2.84 g Na2SO4 (0.02 mol) to 80 mL of deionized water and stir with a magnetic stirrer until completely dissolved to obtain a mixed solution; the concentration of ZnSO4 in the mixed solution is 0.25 M and the concentration of Na2SO4 is 0.25 M.

[0118] (2) Stop the magnetic stirring and let it stand for 10 minutes until the mixed solution is clear before use.

[0119] (3) Measure NMP and FA in a volume ratio of 1:1 and add them to a 5 mL graduated cylinder. Shake well to obtain the composite additive.

[0120] (4) Weigh 48 mg of the composite additive and add it to the mixed solution in step (2), shake well to obtain an electroplating solution containing the composite additive (denoted as O-electroplating solution); the concentration of the composite additive in the electroplating solution is 0.6 g / L.

[0121] 2. Preparation of zinc negative electrode sheet

[0122] (1) Take a copper foil with a thickness of 0.1 mm, wipe the surface with anhydrous ethanol to remove oxides, and dry it; then use a 12 mm punching machine to press it into a circular electrode sheet; prepare a rectangular zinc foil with a size similar to the copper foil, clean the surfaces of the copper foil and zinc foil with deionized water and dry them for later use.

[0123] (2) Place the O-plating solution in a 100 mL beaker, and fix the zinc foil and copper foil parallel to each other on the clamping device of the three-electrode system, ensuring that the electrode spacing (25 mm) is consistent; connect the electrochemical workstation and turn on the power, set the constant current mode, and control the current density to 5 mA / cm. 2 The energizing time is 70 minutes, which allows for the uniform deposition of metallic zinc on the surface of the copper foil.

[0124] (3) Immerse the copper foil plated with metallic zinc in deionized water and ultrasonically clean it for 2 min to remove the residual electroplating solution on the surface. After drying, a zinc negative electrode sheet with a diameter of 12 mm (denoted as O-Cu@Zn) is obtained.

[0125] 3. Assemble an aqueous zinc-ion battery

[0126] For a Zn / / Zn symmetric battery, the positive electrode material is the same as the negative electrode material. The assembly method is as follows: On the negative electrode shell, add O-Cu@Zn (smooth side up), the separator (glass fiber separator), and drop ZnSO4 electrolyte. Then add O-Cu@Zn (smooth side down), add the gasket and spring, and then put on the positive electrode shell for encapsulation to obtain the O-Cu@Zn symmetric battery.

[0127] Using copper foil as the positive electrode and O-Cu@Zn as the negative electrode, an O-Cu@Zn / / Cu half-cell was assembled; (NH4) x VO3 material is used as the positive electrode, and O-Cu@Zn is used as the negative electrode, resulting in O-Cu@Zn / / (NH4). x VO3 full battery.

[0128] Figure 2 The images show physical photographs of copper foil (Cu), the zinc anode A-Cu@Zn from Example 1, and the zinc anodes M-Cu@Zn, N-Cu@Zn, and O-Cu@Zn from Comparative Examples 1-3. As can be seen from the images, in Example 1, the zinc anode A-Cu@Zn obtained by electroplating with solution A- has uniform zinc deposition on the copper foil, resulting in a smooth, flat, and metallic-lustered surface with a relatively thick coating. In contrast, the zinc anodes obtained in Comparative Examples 1-3 by electroplating with solutions M-, N-, and O- respectively exhibit uneven surface deposition, thin coatings, and even areas where no zinc layer is present (where the copper foil is visible).

[0129] Figure 3Figure a shows the X-ray diffraction (XRD) patterns of copper and zinc foils, and figure b shows the XRD patterns of zinc anodes A-Cu@Zn, M-Cu@Zn, N-Cu@Zn, and O-Cu@Zn. As can be seen from the figures, the zinc anode A-Cu@Zn of this invention has a hexagonal zinc (002) crystal plane as its main orientation. The introduction of copper does not change the crystal structure of zinc but significantly improves the deposition behavior. The symmetric cell based on A-Cu@Zn exhibits lower voltage polarization (compared to the control sample) at a current density of 5 mA / cm² and can achieve stable cycling for over 240 hours. In particular, the surface-modified copper sites can induce uniform nucleation of zinc ions, effectively suppressing dendrite growth. Simultaneously, the preferred orientation of the (002) crystal plane further reduces the interfacial energy barrier during the deposition / dissolution process. This invention provides an effective solution to the dendrite problem of anodes in aqueous zinc-ion batteries.

[0130] Figure 4 Scanning electron microscope (SEM) images of the zinc anode A-Cu@Zn of Example 1 and the zinc anodes M-Cu@Zn, N-Cu@Zn, and O-Cu@Zn of Comparative Examples 1-3 are shown. From... Figure 4 As can be seen from this, the surface of the A-Cu@Zn material exhibits a relatively regular layered stacked structure, resulting in a more uniform pore distribution. From... Figure 4 b shows that the surface particle morphology of M-Cu@Zn material is significantly less regular than that of A-Cu@Zn material, with more irregular fragments and insufficient structural uniformity. From Figure 4 c shows that although the N-Cu@Zn material has some regular structure, the size difference between particles is greater, and the morphological consistency is poor. From Figure 4 As can be seen from d, the particle morphology of O-Cu@Zn material is mainly "stacked" or "twisted", with the worst regularity. This irregular morphology is prone to uneven stress inside the electrode and is more likely to cause structural collapse during cycling.

[0131] For symmetrical cells, start with 5 mA / cm 2 Charge at the specified current for 12 minutes, then at 5 mA / cm². 2 Discharge at the specified current for 12 minutes; repeat this cycle of charging and discharging. Figure 5 The constant current charge-discharge test results of A-Cu@Zn symmetric cells, M-Cu@Zn symmetric cells, N-Cu@Zn symmetric cells, and O-Cu@Zn symmetric cells are shown in the figure. Figure 5It can be seen that the A-Cu@Zn symmetric battery of the present invention achieved stable cycling for over 240 hours, exhibiting stable long-cycle performance, while the lifespan of the M-Cu@Zn symmetric battery did not exceed 85 hours, the N-Cu@Zn symmetric battery did not exceed 85 hours, and the O-Cu@Zn symmetric battery did not exceed 155 hours. Furthermore, the polarization voltage of the A-Cu@Zn symmetric battery after 100 cycles was only 60 mV; while the M-Cu@Zn symmetric battery experienced a short circuit after only 85 hours of cycling, with a polarization voltage reaching 64 mV; the polarization voltage of the N-Cu@Zn symmetric battery was 74 mV, and the polarization voltage of the O-Cu@Zn symmetric battery was 68 mV. These results indicate that the zinc anode of the present invention can promote Zn... 2+ Uniform deposition suppresses the growth of zinc dendrites, significantly improving the cycle stability of A-Cu@Zn symmetric cells.

[0132] For a half-cell, start with 5 mA / cm 2 Discharge at a current of 12 min for 12 minutes, then at 5 mA / cm 2 The current is used to charge the battery to 1 V; this charging and discharging cycle is repeated in this manner. Figure 6 The constant current charge-discharge test results for A-Cu@Zn / / Cu half-cells, M-Cu@Zn / / Cu half-cells, N-Cu@Zn / / Cu half-cells, and O-Cu@Zn / / Cu half-cells are shown in the figure. Figure 6 It is known that the M-Cu@Zn / / Cu, N-Cu@Zn / / Cu, and O-Cu@Zn / / Cu half-cells successively experienced short circuits, resulting in a sharp drop in coulombic efficiency. In contrast, the A-Cu@Zn / / Cu half-cell of this invention, using a zinc anode sheet based on A-plating solution, exhibits a smaller decrease in coulombic efficiency over more than 400 cycles and maintains a high level for an extended period, demonstrating excellent cycle stability. Furthermore, compared to the M-Cu@Zn / / Cu, N-Cu@Zn / / Cu, and O-Cu@Zn / / Cu half-cells, the A-Cu@Zn / / Cu half-cell of this invention shows fewer dendrites on the electrode surface after cycling, further verifying the performance advantages of the zinc anode of this invention. In addition, the voltage change of the A-Cu@Zn / / Cu half-cell system of this invention is more stable, with a polarization voltage of 89 mV after 100 cycles, demonstrating good stability during the charge and discharge process.

[0133] Figure 7 This demonstrates A-Cu@Zn / / (NH4). x VO3 full cell, M-Cu@Zn / / (NH4) x VO3 full cell, N-Cu@Zn / / (NH4) x VO3 full cell and O-Cu@Zn / / (NH4) xConstant current charge-discharge test results of VO3 full cells. This invention employs a test method similar to that of symmetrical cells, the difference being that the current setting for the full cell is determined based on the mass of the active material (5 A / g). Assuming the mass of the active material is 1 mg, the initial current is set at 5 mA / cm². 2 It is charged to 1.8 V under constant current at a current of 5 mA / cm². 2 The system discharges at a constant current to 0.4 V; this charging and discharging cycle is repeated. From Figure 7 As can be seen from a, the A-Cu@Zn / / (NH4) of the present invention... x The VO3 full cell has the highest initial specific capacity (230 mAh / g), stable coulombic efficiency, and can cycle normally. Figure 7 b、 Figure 7 c. Figure 7 d、 Figure 7 e represents A-Cu@Zn / / (NH4) x VO3 full cell, M-Cu@Zn / / (NH4) x VO3 full cell, N-Cu@Zn / / (NH4) x VO3 full cell and O-Cu@Zn / / (NH4) x The specific capacity-voltage graph of a VO3 full cell without cycling at different numbers of cycles shows that A-Cu@Zn / / (NH4). x VO3 full cells have the highest energy density and superior stability and reversibility.

[0134] Figure 8 This demonstrates A-Cu@Zn / / (NH4). x CV test results for a full VO3 cell. Figure 8 It can be seen that the potential of the oxidation peak is approximately 1.17 V, corresponding to the cathode material VO3. x- The oxidation process; the reduction peak potential is approximately 0.835 V, corresponding to the cathode material VO3. x- The reduction process; and the symmetrical and sharp peak shape of the CV test results indicate that the electrode of the present invention has good reversibility.

[0135] Figure 9 Figure a demonstrates the use of a multimeter to measure three A-Cu@Zn / / (NH4) atoms. x Voltage diagram of a full VO3 cell in series, b shows three A-Cu@Zn / / (NH4) cells. x The diagram shows a VO3 full-cell series connection used to light an LED. As can be seen from the diagram, the three cells are A-Cu@Zn / / (NH4). x The voltage of a full VO3 cell connected in series is 4.803 V, and the three A-Cu@Zn / / (NH4) groups are... xA VO3 full-cell battery connected in series can easily light up a string of LED lights.

[0136] The above detailed embodiments describe the implementation of the present invention; however, the present invention is not limited to the specific details described in the above embodiments. Within the scope of the claims and technical concept of the present invention, various simple modifications and changes can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

Claims

1. A method for preparing a zinc negative electrode for an aqueous zinc-ion battery, characterized in that, The process includes the following steps: inserting zinc sheets / zinc foils and a metal substrate into an electroplating solution containing zinc salts, sodium salts, and composite additives, and applying an electric current to electroplat and deposit metallic zinc on the surface of the metal substrate to obtain a zinc negative electrode; wherein the composite additives include dimethyl sulfoxide, 1-methyl-2-pyrrolidone, and formamide.

2. The method for preparing the zinc negative electrode of an aqueous zinc-ion battery according to claim 1, characterized in that, The concentration of zinc salt in the electroplating solution is 0.1~0.5 M, the concentration of sodium salt is 0.1~0.5 M, and the concentration of composite additive is 0.2~0.8 g / L.

3. The method for preparing the zinc negative electrode of an aqueous zinc-ion battery according to claim 2, characterized in that, The volume ratio of the dimethyl sulfoxide, 1-methyl-2-pyrrolidone and formamide is (0.5~2):1:(1~3).

4. The method for preparing the zinc negative electrode of an aqueous zinc-ion battery according to claim 2, characterized in that, The pH value of the electroplating solution is 3.0~6.

5.

5. The method for preparing the zinc negative electrode of an aqueous zinc-ion battery according to claim 2, characterized in that, The zinc salts include, but are not limited to, zinc sulfate, and the sodium salts include, but are not limited to, sodium sulfate.

6. The method for preparing the zinc negative electrode of an aqueous zinc-ion battery according to claim 1, characterized in that, The current intensity is 2~15 mA / cm. 2 The power-on time shall not be less than 40 minutes.

7. A zinc anode for an aqueous zinc-ion battery prepared by the method described in any one of claims 1-6.

8. The application of the zinc anode according to claim 7 in the preparation of an aqueous zinc-ion battery.

9. An aqueous zinc-ion battery, characterized in that, Includes the zinc anode as described in claim 7.

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