Electroplating solution for preparing negative electrode of aqueous zinc ion battery and application of electroplating solution

Abstract

The invention discloses electroplating liquid for preparing an aqueous zinc ion battery negative electrode and application of the electroplating liquid, and relates to the technical field of aqueous zinc ion battery negative electrodes. Aiming at the problems of dendritic crystal growth and the like of a zinc negative electrode in an aqueous zinc ion battery, the electroplating liquid is optimized by introducing specific additives, namely L-xylose (L-Xylose) and ribose (Ribose), and the distribution and thickness of a zinc coating on the surface of a copper foil can be adjusted by changing current and electroplating time. According to the zinc negative electrode material prepared by using the electroplating solution, due to the unique petal-shaped three-dimensional structure, more zinc ion deposition sites can be provided, the specific surface area of an electrode can be increased, and the uniformity and reversibility of zinc deposition are remarkably improved. The binding energy of copper and zinc in the copper-zinc compound is high, agglomeration of zinc atoms can be reduced, the petal-shaped copper-zinc compound can reconstruct a solvation structure of Zn < 2 + >, a desolvation energy barrier is reduced, an electrolyte interface double-electrode-layer structure is optimized, and zinc dendrite growth is inhibited, so that the efficiency of the battery is improved, and the service life of the battery is prolonged.

Description

Technical Field

[0001] This invention relates to the field of aqueous zinc-ion battery anode technology, and particularly to an anode plating solution for preparing aqueous zinc-ion batteries. Background Technology

[0002] The unsustainability of traditional fossil fuels is becoming increasingly prominent globally. The current global energy structure urgently requires 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. Zinc metal anodes, with 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, exhibit unique advantages among various anode materials.

[0003] The flammability and explosiveness of traditional organic electrolyte systems have severely hampered the commercialization of zinc-ion batteries. In contrast, zinc-ion batteries (AZIBs) using aqueous electrolytes not only fundamentally solve the safety problem but also offer significant advantages such as low cost and environmental friendliness, making them a research hotspot in the energy storage field.

[0004] In practical applications of batteries, zinc anodes face a serious challenge from dendrite growth. This phenomenon stems from the "sharp effect" during zinc deposition: during electrochemical deposition, zinc ions tend to preferentially deposit on protruding parts of the electrode surface, leading to an increase in local current density, which in turn accelerates the formation and growth of dendrites. These continuously growing zinc dendrites can not only penetrate the separator and cause internal short circuits, but also cause 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 an optimized method for zinc anodes made of copper-zinc composite materials that is low-cost, efficient, and easy to industrialize. Summary of the Invention

[0006] To address the problems of uncontrolled dendrite growth and severe side reactions in existing aqueous zinc-ion batteries, this invention provides an electroplating solution for preparing aqueous zinc-ion battery anodes and its application. L-xylose and ribose are introduced as additives into the aqueous electroplating solution. The zinc anode prepared using this electroplating solution achieves uniform zinc deposition, and its surface microstructure exhibits a petal-like three-dimensional structure. This fundamentally inhibits dendrite formation during use in aqueous zinc-ion batteries, improving cycle stability and lifespan. Specifically, this is achieved through the following techniques.

[0007] This invention provides a method for preparing an aqueous zinc-ion battery negative electrode. Zinc sheets / zinc foils and a metal substrate are used as electrodes, respectively, and are inserted into an electroplating solution. Electricity is applied to electroplat and deposit metallic zinc on the surface of the metal substrate to obtain an aqueous zinc-ion battery negative electrode. The raw materials of the electroplating solution include ZnSO4, Na2SO4, L-xylose and ribose, wherein the concentrations of L-xylose and ribose are both 1-8 g / L.

[0008] Furthermore, the concentrations of both L-xylose and ribose are 7.5 g / L.

[0009] Furthermore, the raw materials of the electroplating solution also include ZnSO4 and Na2SO4, and the ratio of the total concentration of L-xylose and ribose to the total concentration of ZnSO4 and Na2SO4 is 1:(3-5).

[0010] Furthermore, the ratio of the total concentration of L-xylose and ribose to the total concentration of ZnSO4 and Na2SO4 is 1:(3.5-4.5).

[0011] Furthermore, in the raw materials of the electroplating solution, the concentration of ZnSO4 is 15-21 g / L and the concentration of Na2SO4 is 3-6 g / L.

[0012] Furthermore, the concentration of ZnSO4 is 20-21 g / L, and the concentration of Na2SO4 is 3-5 g / L.

[0013] Furthermore, the pH value of the electroplating solution is adjusted to 2.5-6.5.

[0014] Furthermore, the current intensity is 10-100 mA / cm². 2 The power-on time is 40-80 minutes.

[0015] Furthermore, the current intensity is 15 mA / cm². 2 The power-on time is 70 minutes.

[0016] Furthermore, the thickness of the zinc coating on the negative electrode of the aqueous zinc-ion battery is 1-5 μm.

[0017] Optionally, in the above-mentioned method for preparing the negative electrode of an aqueous zinc-ion battery, the metal substrate is generally a metal foil or metal sheet, such as copper foil / copper sheet.

[0018] In the above-mentioned preparation method of the aqueous zinc-ion battery anode of the present invention, an electrochemical workstation is used to adjust the distribution and thickness of the zinc coating on the copper foil surface by changing the current and electroplating time. After cleaning and drying, the best modification effect is obtained, and a zinc anode material with the desired structure is formed.

[0019] In the preparation method of the aqueous zinc-ion battery negative electrode provided by this invention, in addition to the commonly used raw materials sodium sulfate and zinc sulfate, L-xylose and ribose are creatively added to the electroplating solution. The addition of L-xylose and ribose allows the prepared negative electrode to reconstruct the Zn content through its strong polarity. 2+ The solvation of the sheath significantly reduces the desolvation energy barrier and optimizes the double-layer structure at the electrode interface, suppressing side reactions. This multi-component synergistic mechanism effectively guides the uniform deposition of zinc, resulting in a unique petal-like three-dimensional structure on the surface of the zinc anode. This structure provides more zinc ion deposition sites, increases the specific surface area of ​​the electrode, and significantly improves the uniformity and reversibility of zinc deposition. It also fundamentally suppresses dendrite formation, enhancing the cycle stability and lifespan of the battery.

[0020] This invention also provides an aqueous zinc-ion battery anode, prepared using the above-described method; the surface of the aqueous zinc-ion battery anode has a three-dimensional structure in the shape of flower petals. Hereinafter, the aqueous zinc-ion battery anode with a flower petal-shaped copper-zinc composite prepared using the method of this invention will be abbreviated as "L-X+R-Cu@Zn".

[0021] Compared with the prior art, the advantages of the present invention are:

[0022] 1. The zinc-ion battery using the zinc anode of this invention in the electroplating solution exhibits significantly improved cycle stability and superior electrochemical performance.

[0023] 2. The electroplating solution used in this invention has a simple and environmentally friendly preparation method. The zinc anode material can be obtained through a dissolution and electroplating process and can be widely used in aqueous zinc-ion batteries. Attached Figure Description

[0024] Figure 1 In the image, images a and b are SEM images of ordinary Cu@Zn, while images c and d are SEM images of L-X+R-Cu@Zn.

[0025] Figure 2 These are the XRD patterns of ordinary Cu@Zn, L-X+R-Cu@Zn, ordinary Cu, and ordinary Zn.

[0026] Figure 3 These are long-cycle performance graphs of Zn / / Zn symmetric cells assembled using L-X+R-Cu@Zn and ordinary Cu@Zn. Figure a shows the long-cycle performance, figure b shows the capacity-voltage graph of the Zn / / Zn symmetric cell corresponding to L-X+R-Cu@Zn, and figure c shows the capacity-voltage graph of the Zn / / Zn symmetric cell corresponding to ordinary Cu@Zn.

[0027] Figure 4This refers to Zn / / (NH4) corresponding to L-X+R-Cu@Zn and ordinary Cu@Zn. x The test results for VO3 full cells at a current density of 5 A / g and a charge-discharge range of 0.4–1.8 V are shown. Figure a shows the Zn / / (NH4) corresponding to L-X+R-Cu@Zn and ordinary Cu@Zn. x Cyclic performance and coulombic efficiency of VO3 full cells. Figure b shows the Zn / / (NH4) equivalent to L-X+R-Cu@Zn. x The specific capacity-voltage diagram of a VO3 full cell; diagram c shows the Zn / / (NH4) corresponding to ordinary Cu@Zn. x Specific capacity-voltage diagram of a VO3 full cell.

[0028] Figure 5 For L-X+R-Cu@Zn, the corresponding Zn / / (NH4) x Cyclic voltammetry (CV) performance test results of VO3 full cells.

[0029] Figure 6 The images show a comparison of physical samples of L-X+R-Cu@Zn and ordinary Cu@Zn. Image a shows the physical sample of L-X+R-Cu@Zn, and image b shows the physical sample of ordinary Cu@Zn. Detailed Implementation

[0030] 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.

[0031] In some embodiments of the present invention, a method for preparing an aqueous zinc-ion battery negative electrode is provided. Specifically, zinc sheet / zinc foil and a metal substrate are used as electrodes, respectively, inserted into an electroplating solution, and energized to electroplat and deposit metallic zinc on the surface of the metal substrate to obtain an aqueous zinc-ion battery negative electrode.

[0032] The raw materials of the electroplating solution include ZnSO4, Na2SO4, L-xylose and ribose, wherein the concentrations of L-xylose and ribose are both 1-8 g / L.

[0033] Optionally, the concentrations of both L-xylose and ribose are 7.5 g / L.

[0034] Optionally, the raw materials of the electroplating solution also include ZnSO4 and Na2SO4, and the ratio of the total concentration of L-xylose and ribose to the total concentration of ZnSO4 and Na2SO4 is 1:(3-5).

[0035] Specifically, the ratio of the total concentration of L-xylose and ribose to the total concentration of ZnSO4 and Na2SO4 is 1:(3.5-4.5).

[0036] Optionally, the concentration of ZnSO4 in the raw materials of the electroplating solution is 15-21 g / L, and the concentration of Na2SO4 is 3-6 g / L.

[0037] Specifically, the concentration of ZnSO4 is 20-21 g / L, and the concentration of Na2SO4 is 3-5 g / L.

[0038] The electroplating solution used in the preparation of the negative electrode of the aqueous zinc-ion battery in this invention has a pH value of 2.5-6.5.

[0039] Optionally, the current intensity applied during electroplating is 10-100 mA / cm. 2 The power-on time is 40-80 minutes.

[0040] Specifically, the current intensity applied during electroplating is 15 mA / cm². 2 The power-on time is 70 minutes.

[0041] Optionally, the thickness of the zinc coating on the negative electrode of the aqueous zinc-ion battery is 1-5 μm.

[0042] In the following specific implementation examples, the zinc anode of the petal-shaped copper-zinc composite prepared by the above method is referred to as "L-X+R-Cu@Zn".

[0043] In other embodiments of the present invention, a water-zinc zinc-ion battery prepared using the above-described zinc negative electrode assembly is provided. Depending on the positive electrode material, water-zinc zinc-ion batteries include Zn / / Zn symmetric cells and Zn / / (NH4) cells. x VO3 full cell. The zinc-water ion battery was assembled using methods commonly used in the art.

[0044] Experimental Example 1

[0045] 1. Preparation of electroplating solutions containing L-xylose and ribose, as well as ordinary electroplating solutions.

[0046] Weigh ZnSO4•7H2O and Na2SO4 and place them in a beaker. Add deionized water and stir for 3-5 minutes to obtain a common electroplating solution.

[0047] Weigh out L-xylose and ribose, add them to a regular electroplating solution, and stir for 5 minutes to obtain an electroplating solution containing L-xylose and ribose (hereinafter referred to as "L-X+R electroplating solution").

[0048] The concentrations of ZnSO4, Na2SO4, L-xylose, and ribose were 21 g / L, 5 g / L, 7.5 g / L, and 7.5 g / L, respectively.

[0049] 2. Electroplating for the preparation of zinc anode materials

[0050] A copper foil with a thickness of 15 μm was selected, and the pressure was 15 mA / cm. 2 Under the current, L-X+R electroplating solution and ordinary electroplating solution are electroplated for 70 min. The negative electrode sheet is then removed, rinsed, and dried to obtain L-X+R-Cu@Zn zinc negative electrode and ordinary Cu@Zn negative electrode. The zinc coating thickness on the surface of L-X+R-Cu@Zn zinc negative electrode and ordinary Cu@Zn negative electrode is about 17 μm.

[0051] like Figure 1 As shown in Figures a and b, the surface of the ordinary Cu@Zn negative electrode sheet prepared by electroplating with a common electroplating solution has a typical sheet-like structure. Figures c and d show that the surface of the L-X+R-Cu@Zn negative electrode sheet has numerous petal-like three-dimensional structures. This structure effectively prevents the formation of zinc dendrites and side reactions. In contrast, ordinary Cu foil induces the formation of Zn... 2+ Deposited on the (002) crystal plane.

[0052] Scanning by SEM electron microscopy Figure 1 As can be seen from (b) and (c), the lamellar structure on the surface of the L-X+R-Cu@Zn negative electrode is denser and more spread out, which is more conducive to Zn production. 2+ The deposition effectively prevents the formation of zinc dendrites and side reactions.

[0053] The XRD patterns of ordinary Cu@Zn, L-X+R-Cu@Zn, ordinary Cu foil, and ordinary Zn foil in this embodiment are as follows: Figure 2 As shown. It can be seen that the peak intensity ratio of I(101) / I(002) of L-X+R-Cu@Zn is 0.831175836, while that of ordinary Cu@Zn is 0.481860465. The (101) crystal plane accounts for a larger proportion in L-X+R-Cu@Zn.

[0054] The Zn, Cu, and L-X+R-Cu samples are consistent with the standard PDF card (used to analyze whether the substance is present; if the characteristic peaks of the XRD in the raw material are consistent with those on the PDF card, it indicates that the content of the material is very high and there are basically no impurities), indicating that the sample has high purity. The L-X+RCu@Zn sample has the same characteristic peak as Zn in the figure, indicating that Zn was successfully deposited on the surface of the L-X+R-Cu copper foil.

[0055] 3. Assemble Zn / / Zn symmetric cells and Zn / / (NH4) cells. x VO3 full battery

[0056] (1) Weigh 5.7312 g of ZnSO4•7H2O into a beaker, add 10 mL of distilled water to dissolve it, and obtain the electrolyte.

[0057] (NH4) x Preparation of the positive electrode sheet for a VO3 full cell: Ammonium vanadate ((NH4)) is used as the positive electrode active material. x VO3), conductive agent acetylene black, and binder polyvinylidene fluoride are mixed in a mass ratio of 7:2:1 to form a uniform positive electrode slurry; the positive electrode slurry is coated onto a carbon paper substrate and dried to obtain (NH4). x The positive electrode sheet of the VO3 full cell is finally stamped with a diameter of 12 mm.

[0058] A stamping machine is used to prepare zinc and copper sheets with a diameter of 12 mm as positive electrodes, zinc sheets with a diameter of 15 mm as negative electrodes, and a diaphragm with a diameter of 16 mm.

[0059] (2) Assemble the Zn / / Zn symmetrical battery: Assemble the negative electrode shell, zinc negative electrode sheet (L-X+R-Cu@Zn zinc negative electrode, or ordinary zinc negative electrode), separator, electrolyte, positive electrode sheet, gasket, spring sheet, and positive electrode shell in sequence, and put the battery into the equipment and press it to obtain the corresponding L-X+R-Cu@Zn / / Zn symmetrical battery and ordinary Cu@Zn / / Zn symmetrical battery.

[0060] Assemble Zn / / (NH4) x VO3 full cell: Using the same method as the Zn / / Zn symmetric cell, a 12 mm diameter (NH4) cell was prepared in step (1). x Zn / / (NH4) was prepared by replacing the zinc cathode with a VO3 full cell cathode. x VO3 full cell, i.e., L-X+R-Cu@Zn / / (NH4) x VO3 full cell and ordinary Cu@Zn / / (NH4) x VO3 full battery.

[0061] 4. Performance testing of Zn / / Zn symmetric cells

[0062] The assembled Zn / / Zn symmetric cell was tested using a blue electric field testing system. The test result was 5 mA / cm². 2 Current density, 1 mAh / cm 2 Under specific capacity, constant current charge-discharge tests were performed. Specifically, the tests were conducted according to the following conditions: static setting, 5 mA / cm² charge-discharge rate. 2Constant current charging, resting, 5 mA / cm 2 The constant current discharge sequence and resting time were 30 s, and the constant current charge and discharge time was 0.2 h.

[0063] Test results are as follows Figure 3 As shown, figure a represents the long-cycle performance of L-X+R-Cu@Zn and ordinary Cu@Zn Zn symmetric cells. Figure b represents the capacity-voltage diagram of the L-X+R-Cu@Zn Zn symmetric cell, and figure c represents the capacity-voltage diagram of the ordinary Cu@Zn Zn symmetric cell. From Figure 3 As can be seen, the Zn / / Zn symmetric cell assembled using the L-X+R-Cu@Zn anode provided by this invention exhibits stable cycle performance. Due to the suppression of zinc dendrite growth, the polarization voltage and nucleation overpotential are significantly reduced.

[0064] 5. Zn / / (NH4) x VO3 full battery performance test

[0065] The assembled Zn / / (NH4) x The VO3 full battery was tested on the Blue Electric testing system. The test showed that constant current charging and discharging was performed under conditions of 5 A / g current density and a charge / discharge range of 0.4-1.8 V. For example... Figure 4 As shown, Figure a is a (NH4) assembly using L-X+R-Cu@Zn and ordinary Cu@Zn. x Cyclic performance and coulombic efficiency plots of VO3 / / Zn full cells; plot b shows (NH4) assembled using L-X+R-Cu@Zn. x Specific capacity-voltage diagrams for VO3 / / Zn full cells; diagram c shows (NH4) assembled using ordinary Cu@Zn. x Specific capacity-voltage diagram of the VO3 / / Zn full cell. It can be seen that L-X+R-Cu@Zn has Zn / / (NH4) x VO3 full-cell batteries exhibit better cycle stability, and with increasing cycle count, plateau decay is slower and polarization voltage is lower.

[0066] Experimental Example 2

[0067] The aqueous zinc-ion battery negative electrode sheet provided in this embodiment is prepared in a basically the same way as that in Example 1, except that the electroplating time is set to 1 h.

[0068] Experimental Example 3

[0069] The aqueous zinc-ion battery negative electrode sheet provided in this embodiment is prepared in a basically the same way as in Example 1, except that the assembled Zn / / Zn symmetric cell and Zn / / (NH4) are different. xThe standard specification model of VO3 full battery is 2032, and the negative electrode shell and positive electrode shell selected are model 2032.

[0070] 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 an aqueous zinc-ion battery negative electrode, characterized in that, Zinc sheets / zinc foils and a metal substrate are used as electrodes, respectively, and are inserted into an electroplating solution. When an electric current is applied, metallic zinc is deposited on the surface of the metal substrate to obtain the negative electrode of an aqueous zinc-ion battery. The raw materials of the electroplating solution include ZnSO4, Na2SO4, L-xylose and ribose, wherein the concentrations of L-xylose and ribose are both 1-8 g / L.

2. The method for preparing the negative electrode of an aqueous zinc-ion battery according to claim 1, characterized in that, The concentrations of L-xylose and ribose were both 7.5 g / L.

3. The method for preparing the negative electrode of an aqueous zinc-ion battery according to claim 1, characterized in that, The raw materials of the electroplating solution also include ZnSO4 and Na2SO4, and the ratio of the total concentration of L-xylose and ribose to the total concentration of ZnSO4 and Na2SO4 is 1:(3-5).

4. The method for preparing the negative electrode of an aqueous zinc-ion battery according to claim 3, characterized in that, The concentration of ZnSO4 in the raw materials of the electroplating solution is 15-21 g / L, and the concentration of Na2SO4 is 3-6 g / L. Furthermore, the concentration of ZnSO4 is 20-21 g / L, and the concentration of Na2SO4 is 3-5 g / L.

5. The method for preparing the negative electrode of an aqueous zinc-ion battery according to claim 1, characterized in that, Adjust the pH of the electroplating solution to 2.5-6.

5.

6. The method for preparing the negative electrode of an aqueous zinc-ion battery according to claim 1, characterized in that, The current intensity is 10-100 mA / cm. 2 The power-on time is 40-80 minutes.

7. The method for preparing the aqueous zinc-ion battery negative electrode according to claim 6, characterized in that, The current intensity is 15 mA / cm. 2 The power-on time is 70 minutes.

8. The method for preparing the negative electrode of an aqueous zinc-ion battery according to claim 1, characterized in that, The thickness of the zinc coating on the negative electrode of the aqueous zinc-ion battery is 1-5 μm.

9. A negative electrode for an aqueous zinc-ion battery, characterized in that, It is prepared by any one of the preparation methods described in claims 1-8; the surface of the aqueous zinc-ion battery negative electrode has a three-dimensional structure in the shape of flower petals.

10. The application of the aqueous zinc-ion battery negative electrode according to claim 9 in the preparation of an aqueous zinc-ion battery.

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