Preparation method and application of metal interface layer coated zinc powder negative electrode

Abstract

The invention belongs to the technical field of secondary battery processing, and particularly relates to a preparation method of a metal interface layer coated zinc powder negative electrode, which comprises the following steps: adding an additive into a solvent, continuously stirring for 0.5-6 hours, then adding a zinc salt and other metal salts, and continuously stirring until the solution is transparent; taking a platinum net as a counter electrode and a reference electrode, taking zinc powder as a working electrode, carrying out electro-deposition under the condition of constant current or constant voltage, and keeping for 0.1-12 hours; then drying to obtain a zinc powder negative electrode with a metal interface layer; the preparation process is simple, pollution-free, mild in reaction condition, high in safety, low in production cost and suitable for large-scale production, deposition of metal elements can be achieved by preparing the metal interface coating through an electro-deposition method, and low deposition overpotential and long circulation stability of the zinc powder negative electrode are guaranteed by introducing a metal interface.

Description

Technical Field

[0001] The present invention belongs to the technical field of secondary battery processing, and particularly relates to a preparation method and application of a zinc powder negative electrode coated with a metal interface layer. Background Art

[0002] With the continuous growth of global energy demand and the severe challenges faced by traditional lithium-ion batteries in terms of cost and safety, aqueous zinc-ion batteries have become a highly competitive large-scale energy storage solution due to their unique advantages (such as a high theoretical capacity of 820 mAh / g, a low redox potential of -0.76 V, abundant reserves, environmental friendliness, and intrinsic safety). However, this system still faces defects such as uncontrollable growth of zinc dendrites, hydrogen evolution side reactions, and electrode corrosion in practical applications, seriously affecting the cycle stability and safety of the battery. For the optimization of the electrochemical performance of the zinc negative electrode, researchers have proposed various strategies, such as negative electrode structure design, electrolyte composition optimization, and interfacial modification between the negative electrode and the electrolyte, to achieve dendrite-free deposition during the electrochemical cycling process.

[0003] Although significant progress has been made in the modification strategies of zinc foil negative electrodes, their inherent limitations have not been fundamentally solved. The zinc foil serves both as a current collector and a working electrode, resulting in low zinc utilization; the excessive zinc content further reduces the energy density of the battery. In contrast, zinc powder negative electrodes exhibit greater potential in practical applications due to advantages such as low cost, adjustable structure, and easy processability. The high specific surface area of zinc powder improves the utilization rate and reaction activity of zinc, thus significantly increasing the energy density and power output of the battery, but at the same time, it also exacerbates the occurrence of dendrite growth and side reactions.

[0004] Currently, the modification research of zinc powder negative electrodes mostly focuses on structure design (such as three-dimensional carbon / polymer composite frameworks) and electrolyte optimization (such as the introduction of additives). For example, a Chinese patent with patent application number CN202411145863.8 and application date August 20, 2024 discloses "an electrolyte containing composite additives for a zinc powder negative electrode, its preparation method, and an aqueous zinc-ion battery". In this invention, by using a mixture of amino acid compounds and saccharide compounds as composite electrolyte additives, the solvation structure of zinc ions can be adjusted to achieve uniform zinc deposition, effectively inhibiting the growth of zinc dendrites, reducing passivation phenomena and side reactions on the electrode surface, and significantly improving the cycle stability of the zinc powder negative electrode. In addition, a Chinese patent with patent application number CN202411543375.2 and application date October 31, 2024 discloses "a zinc powder negative electrode material with (002) crystal plane orientation, its preparation method, and application". By controlling the processes of ball milling and annealing, the morphology and crystal plane structure of zinc powder are optimized, inducing the formation of a zinc powder negative electrode material with (002) crystal plane orientation, effectively inhibiting the formation of zinc dendrites, and presenting a more compact packing morphology.

[0005] However, these inventions mainly focus on the structural design of electrolytes and zinc powder. On the one hand, directly modifying the zinc powder anode is beneficial to more directly and fundamentally solve the problem of zinc powder dendrite growth. On the other hand, most of the current modification operations for zinc powder anodes are cumbersome and require heat treatment, which is not conducive to large-scale production and has a high cost. The exploration of surface modification of metal coatings (such as tin, bismuth, copper, indium, silver, lead, etc.) is relatively limited. Therefore, it is crucial to develop a low-cost and easily preparable metal interface layer. Summary of the Invention

[0006] In view of this, the purpose of the present invention is to overcome the serious zinc dendrite and side reaction problems of the existing zinc powder anode, improve the cycle stability of the anode, and provide a preparation method and application of a zinc powder anode material with the ability to inhibit the formation of zinc dendrites. By using the electrodeposition method to prepare a metal interface coating, the deposition of metal elements can be achieved, with a simple, safe, environmentally friendly, and low-cost process; by introducing a metal interface, a low deposition overpotential and long cycle stability of the zinc powder anode are ensured.

[0007] To achieve the above purpose, the present invention adopts the following technical solutions: The present invention provides a method for preparing a zinc powder anode material with a metal coating, which specifically includes the following steps: Add an additive to a solvent, continuously stir for 0.5 - 6 h, then add zinc salt and other metal salts, and continue stirring until the solution is transparent; use a platinum mesh as the counter electrode and reference electrode, and zinc powder as the working electrode, and perform electrodeposition under constant current or constant voltage conditions for 0.1 - 12 h; then dry in vacuum or air at room temperature or other temperatures for 5 - 24 h to obtain a zinc powder anode with a metal interface layer.

[0008] Further, the additive includes but is not limited to one or several of sodium citrate, disodium ethylenediaminetetraacetate, citric acid, polyethylene glycol, boric acid, sodium dodecyl sulfate, oxalic acid, ascorbic acid, hydroquinone, and the molar ratio of the additive to the zinc salt is 0.1:10 - 10:0.1.

[0009] Further, the solvent includes but is not limited to one or several of water, ethylene glycol, isopropyl alcohol, acetone, and propylene glycol.

[0010] Further, the zinc salt includes but is not limited to one or several combinations of zinc sulfate, zinc chloride, and zinc acetate that can provide a zinc source.

[0011] Further, the other metal salt includes but is not limited to any one of soluble tin salts, bismuth salts, copper salts, indium salts, silver salts, lead salts, aluminum salts, manganese salts, and magnesium salts. The molar ratio of the zinc salt to the other metal salt is 0.1:10 - 10:0.1.

[0012] Among them, the tin salt includes but is not limited to one or several combinations of stannous chloride, stannous sulfate, sodium stannate, stannous fluoride that can provide a tin source; the bismuth salt includes but is not limited to one or several combinations of bismuth nitrate, bismuth chloride, bismuth acetate that can provide a bismuth source; the copper salt includes but is not limited to one or several combinations of copper sulfate, copper chloride, copper nitrate that can provide a copper source; the indium salt includes but is not limited to one or several combinations of indium sulfate, indium chloride, indium chloride, nitrate that can provide an indium source; the silver salt includes but is not limited to one or several combinations of silver acetate, silver phosphate that can provide a silver source; the lead salt includes but is not limited to one or several combinations of lead carbonate, lead sulfate, lead acetate that can provide a lead source; the aluminum salt includes but is not limited to one or several combinations of aluminum sulfate, aluminum chloride, aluminum nitrate, aluminum phosphate that can provide an aluminum salt; the manganese salt includes but is not limited to one or several combinations of manganese acetate, manganese sulfate, manganese chloride, manganese nitrate that can provide an aluminum salt; the magnesium salt includes but is not limited to one or several combinations of magnesium sulfate, magnesium chloride, magnesium perchlorate that can provide an aluminum salt.

[0013] Furthermore, the zinc powder substrate includes one or several of a commercial zinc powder negative electrode and various modified zinc powder negative electrode sheets.

[0014] Furthermore, the direct distance between the counter electrode and the working electrode is 5 cm.

[0015] Furthermore, the constant current condition for electrodeposition is 0.1 mA~10 A cm -2 , and the constant voltage condition for electrodeposition is 0.1V~50 V.

[0016] Furthermore, the metal interface layer includes but is not limited to one or several of Zn-Sn, Zn-Bi, Zn-Cu, Zn-In, Zn-Ag, Zn-Pb, Zn-Al, Zn-Mn, Zn-Mg.

[0017] The zinc powder negative electrode material with a metal interface of the present invention is used to prepare a secondary energy storage battery. Specifically, a secondary battery is constructed with a positive electrode, a zinc powder negative electrode with a metal interface, an electrolyte, and a separator.

[0018] Furthermore, the positive electrode includes one or several of a manganese-based positive electrode, a vanadium-based positive electrode, a Prussian blue positive electrode, and an organic positive electrode material, and a secondary battery can be assembled under conventional conditions.

[0019] Compared with the prior art, the beneficial effects of the present invention are: (1), The preparation process of the present invention is simple, pollution-free, the reaction conditions are mild, the safety is high, and the production cost is low, which is suitable for large-scale production.

[0020] (2) The modified zinc powder negative electrode material prepared by the present invention has the following advantages: the metal interface layer is uniform and dense, which can effectively isolate the direct contact between the zinc powder and the electrolyte, and effectively reduce the interfacial corrosion; the zincophilic particles on the surface of the metal interface layer can provide more nucleation sites, effectively reduce the nucleation barrier of zinc, promote the uniform deposition of zinc, and inhibit dendrite growth.

[0021] (3) The metal coating formed on the surface of the zinc powder is beneficial to promoting the rapid ion transport, realizing the uniform zinc stripping and deposition. The obtained zinc ion battery has excellent cycle stability and can stably cycle for 1500 hours at a current density of 1 mA / cm 2 , which is much higher than that of ordinary commercial zinc powder negative electrodes; when assembled with MnO2 into a full cell, the cycle stability performance of the full cell is improved, and it can cycle 1800 times without capacity decay at a current density of 1 A / g. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained according to the provided drawings.

[0023] Figure 1 It shows the SEM image of the commercial zinc powder used in this embodiment; Figure 2 It shows the SEM image of the zinc powder negative electrode with a zinc-tin metal coating prepared in Example 1; Figure 3 It shows the XRD spectrum of the zinc powder negative electrode with a zinc-tin metal coating prepared in Example 1; Figure 4 It shows the long cycle stability test chart of the symmetric cell prepared from the commercial zinc powder and Example 1; Figure 5 It shows the long cycle stability test chart of the copper asymmetric cell prepared from the commercial zinc powder and Example 1; Figure 6 It shows the long cycle stability test chart of the full cell prepared from the commercial zinc powder and Example 1. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0024] The technical solutions of the present invention will be further described below in conjunction with specific embodiments. However, the present invention is not limited to these embodiments. At the same time, in order to better illustrate the content of the present application, numerous specific details are given in the following specific embodiments. Those skilled in the art should understand that the present application can also be implemented without certain specific details. In the embodiments, some methods, means, instruments, equipment, etc. well-known to those skilled in the art are not described in detail in order to highlight the main idea of the present application. On the premise of no conflict, the technical features disclosed in the embodiments of the present application can be arbitrarily combined, and the obtained technical solutions belong to the content disclosed in the embodiments of the present application. Example 1

[0025] Cut multiple commercial zinc powders of 5×5 cm, wipe the impurities on the surface with alcohol, and air dry for later use.

[0026] Weigh 0.2 mol of sodium citrate and 0.2 mol of disodium ethylenediaminetetraacetate respectively, dissolve them in 900 ml of deionized water, and seal the beaker with plastic wrap. After complete dissolution, add 0.2 mol of zinc sulfate heptahydrate and 0.06 mol of tin sulfate respectively, and stir well to dissolve to obtain the electroplating solution.

[0027] Use the pretreated commercial zinc powder as the cathode and the platinum mesh as the anode for constant current electroplating for 30 min. Among them, the direct distance between the cathode and the anode is 5 cm, and the current density is 10 mA / cm 2 .

[0028] After electroplating, take out the commercial zinc powder, wash it repeatedly with deionized water to wash off the residual metal salts on the surface, and then air dry at room temperature to obtain the modified zinc powder negative electrode material with a metal coating.

[0029] This embodiment provides an aqueous zinc-ion battery, which is assembled by the following method: Assemble the zinc powder electrode into a button battery, inject the electrolyte, and the electrolyte is 2 mol / L ZnSO4, which is a symmetric battery.

[0030] The SEM images of the negative electrode material prepared in this embodiment before and after electrochemical deposition are respectively as Figure 1 and Figure 2 shown. It can be seen from the figure that after deposition, zinc-tin microparticles are evenly distributed on the surface of the zinc powder, and the microparticle dendrites are about 3 μm.

[0031] Figure 3XRD pattern of the zinc powder negative electrode with a zinc-tin metal coating in Example 1. It can be seen from the figure that obvious diffraction peaks of zinc and tin appear in the sample, which correspond to the standard peaks of Zn (JCPDS No. 87-0713) and Sn (JCPDS No. 04-0673) respectively, indicating the successful preparation of the zinc-tin metal coating.

[0032] Test the cycling performance of the zinc-ion symmetric battery assembled in Example 1. As Figure 4 shown, in the long cycle with a current density of 2 mA / cm 2 and an areal capacity of 0.5 mAh / cm 2 , the symmetric battery of Example 1 stably cycled for more than 1200 hours, with an initial polarization voltage of only 35 mV, while the symmetric battery of commercial zinc powder failed after 150 hours, and the initial polarization voltage was 150 mV. The above results show that the zinc powder negative electrode with a zinc-tin metal coating of the present invention exhibits good cycling stability at a current density of 2 mA / cm 2 .

[0033] Test the cycling performance of the zinc-ion copper asymmetric battery assembled in Example 1. As Figure 5 shown, in the long cycle with a current density of 5 mA / cm 2 , the asymmetric battery of Example 1 stably operated for 2500 cycles, with an average Coulombic efficiency of 99.6%, while the asymmetric battery of commercial zinc powder failed after about 200 cycles, and the Coulombic efficiency was lower and unstable. This low Coulombic efficiency is due to the unstable deposition / stripping of zinc, further proving that the zinc powder negative electrode with a zinc-tin metal coating can effectively regulate the uniform deposition of zinc.

[0034] Test the cycling performance of the zinc-ion full battery assembled in Example 1. As Figure 6 shown, at a current density of 1 A / g, the full battery of Example 1 stably cycled for 1800 cycles with almost no capacity decay, while the full battery of commercial zinc powder showed obvious capacity decay, demonstrating the excellent cycling stability of the present invention in the full battery. Example 2

[0035] Cut multiple 5×5 cm commercial zinc powders, wipe off the impurities on the surface with alcohol, and air dry for later use.

[0036] Weigh 0.2 mol of sodium citrate and 0.2 mol of disodium ethylenediaminetetraacetate respectively, dissolve them in 900 ml of deionized water, and seal the beaker with plastic wrap. After complete dissolution, add 0.2 mol of zinc sulfate heptahydrate and 0.1 mol of lead sulfate respectively, and stir well to dissolve to obtain the electroplating solution.

[0037] Use the pretreated commercial zinc powder as the cathode and the platinum mesh as the anode for constant current electroplating for 30 min. Among them, the direct distance between the cathode and the anode is 5 cm, and the current density is 10 mA / cm 2 .

[0038] After electroplating, take out the commercial zinc powder, wash it repeatedly with deionized water to remove the residual metal salts on the surface, and then dry it naturally at room temperature to obtain the modified zinc powder negative electrode material with a zinc-lead metal coating. Example 3

[0039] Cut out multiple pieces of commercial zinc powder with a size of 5×5 cm, wipe off the impurities on the surface with alcohol, and let it dry naturally for later use.

[0040] Weigh 0.2 mol of sodium citrate and 0.2 mol of disodium ethylenediaminetetraacetate respectively, dissolve them in 900 ml of deionized water, and seal the beaker with plastic wrap. After complete dissolution, add 0.2 mol of zinc sulfate heptahydrate and 0.02 mol of copper sulfate pentahydrate respectively, and stir well to dissolve to obtain the electroplating solution.

[0041] Use the pretreated commercial zinc powder as the cathode and the platinum mesh as the anode for constant current electroplating for 30 min. Among them, the direct distance between the cathode and the anode is 5 cm, and the current density is 20 mA / cm 2 .

[0042] After electroplating, take out the commercial zinc powder, wash it repeatedly with deionized water to remove the residual metal salts on the surface, and then dry it naturally at room temperature to obtain the modified zinc powder negative electrode material with a zinc-copper metal coating. Example 4

[0043] Cut out multiple pieces of commercial zinc powder with a size of 5×5 cm, wipe off the impurities on the surface with alcohol, and let it dry naturally for later use.

[0044] Weigh 0.2 mol of sodium citrate and 0.2 mol of disodium ethylenediaminetetraacetate respectively, dissolve them in 900 ml of deionized water, and seal the beaker with plastic wrap. After complete dissolution, add 0.2 mol of zinc sulfate heptahydrate and 0.04 mol of bismuth nitrate pentahydrate respectively, and stir well to dissolve to obtain the electroplating solution.

[0045] Use the pretreated commercial zinc powder as the cathode and the platinum mesh as the anode for constant current electroplating for 30 min. Among them, the direct distance between the cathode and the anode is 5 cm, and the current density is 10 mA / cm 2 .

[0046] After electroplating, the commercial zinc powder was taken out, repeatedly washed with deionized water to wash away the residual metal salts on the surface, and then naturally dried at room temperature to obtain a modified zinc powder negative electrode material with a zinc-bismuth metal coating. Example 5

[0047] Cut multiple pieces of commercial zinc powder of 5×5 cm, wipe off the impurities on the surface with alcohol, and air dry for later use.

[0048] Weigh 0.2 mol of sodium citrate and 0.2 mol of disodium ethylenediaminetetraacetate respectively, dissolve them in 900 ml of deionized water, and seal the beaker with plastic wrap. After complete dissolution, add 0.2 mol of zinc sulfate heptahydrate and 0.01 mol of indium sulfate respectively, and stir well to dissolve to obtain an electroplating solution.

[0049] Use the pretreated commercial zinc powder as the cathode and a platinum mesh as the anode for constant current electroplating for 20 min. Among them, the direct distance between the cathode and the anode is 5 cm, and the current density is 15 mA / cm 2 .

[0050] After electroplating, the commercial zinc powder was taken out, repeatedly washed with deionized water to wash away the residual metal salts on the surface, and then naturally dried at room temperature to obtain a modified zinc powder negative electrode material with a zinc-indium metal coating.

[0051] In summary, the electro-deposition method adopted by the present invention to prepare a metal interface coating can achieve the deposition of metal elements, with a simple, safe, environmentally friendly and cost-saving process; by introducing a metal interface, the low deposition overpotential and long cycle stability of the zinc powder negative electrode are ensured.

[0052] Although the present invention has been illustrated and described with reference to specific embodiments, it will be apparent to those skilled in the art that many other changes and modifications can be made without departing from the spirit and scope of the invention. Therefore, all such changes and modifications that fall within the scope of the present invention are consciously included in the appended claims.

Claims

1. A preparation method of a zinc powder negative electrode coated with a metal interface layer, characterized in that, It includes the following steps: Add an additive into a solvent, continuously stir for 0.5 - 6 h, then add a zinc salt and other metal salts, and continue stirring until the solution becomes transparent; use a platinum mesh as the counter electrode and reference electrode, and zinc powder as the working electrode, and perform electrodeposition under the condition of constant current or constant voltage for 0.1 - 12 h; then dry to obtain a zinc powder negative electrode with a metal interface layer; Among them, the additive is at least one of sodium citrate, disodium ethylenediaminetetraacetate, citric acid, polyethylene glycol, boric acid, sodium dodecyl sulfate, oxalic acid, ascorbic acid, hydroquinone; The solvent is at least one of water, ethylene glycol, isopropyl alcohol, acetone, propylene glycol; The zinc salt is at least one of zinc sulfate, zinc chloride, zinc acetate; The other metal salt is any one of soluble tin salts, bismuth salts, copper salts, indium salts, silver salts, lead salts, aluminum salts, manganese salts, magnesium salts; 2. The preparation method of a zinc powder-coated negative electrode with a metal interface layer according to claim 1, characterized in that The molar ratio of the additive to the zinc salt is 0.1:10 - 10:0.1; 3. The preparation method of a zinc powder-coated negative electrode with a metal interface layer according to claim 1, characterized in that The molar ratio of the zinc salt to the other metal salt is 0.1:10 - 10:0.1; 4. The preparation method of a zinc powder-coated negative electrode with a metal interface layer according to claim 1, characterized in that, The zinc powder substrate includes at least one of a commercial zinc powder negative electrode and various modified zinc powder negative electrode sheets; 5. The preparation method of a zinc powder-coated negative electrode with a metal interface layer according to claim 1, characterized in that, The direct distance between the counter electrode and the working electrode is 5 cm; 6. The preparation method of a zinc powder-coated negative electrode with a metal interface layer according to claim 1, wherein The electro-deposition constant current condition is 0.1 mA to 10 A cm -2 , and the electro-deposition constant voltage condition is 0.1 V to 50 V.

7. The preparation method of a zinc powder-coated negative electrode with a metal interface layer according to claim 1, wherein The metal interface layer is at least one of Zn - Sn, Zn - Bi, Zn - Cu, Zn - In, Zn - Ag, Zn - Pb, Zn - Al, Zn - Mn, Zn - Mg; 8. The preparation method of a zinc powder-coated negative electrode with a metal interface layer according to claim 1, characterized in that, The drying time is 5 - 24 h, and the drying temperature is room temperature; 9. A secondary battery, characterized in that, It includes a positive electrode, a zinc powder negative electrode prepared by the preparation method of the metal interface layer - coated zinc powder negative electrode according to any one of claims 1 - 8, an electrolyte, and a separator; 10. According to a secondary battery as claimed in claim 9, the positive electrode includes at least one of a manganese - based positive electrode, a vanadium - based positive electrode, a Prussian blue positive electrode, and an organic positive electrode material.

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