A zinc metal negative and zinc-ion battery

Abstract

The application belongs to the technical field of zinc ion batteries, and particularly relates to a zinc metal negative electrode and a zinc ion battery. The zinc metal negative electrode comprises a zinc metal substrate and a coating layer covering the surface of the zinc metal substrate; the coating layer comprises a conductive metal oxide; and the coating layer is formed on the zinc metal substrate in a manner independent of an organic polymer binder. This scheme avoids the use of an insulating organic polymer binder, thereby helping to improve the conductivity of the coating layer and improve the controllability of the structure. Furthermore, high-conductivity indium tin oxide (ITO) nanorods are prepared through microwave solvent synthesis and high-temperature calcination in cooperation, and an adhesive-free and structure-controllable protective layer is constructed on the surface of a zinc foil by using electrophoretic deposition technology.

Description

Technical Field

[0001] This invention belongs to the field of zinc-ion battery technology, specifically relating to a zinc metal anode and a zinc-ion battery. Background Technology

[0002] Rechargeable zinc-ion batteries represent a promising new energy storage system. Currently, lithium resources face cost and supply pressures, while zinc boasts significant advantages such as abundant reserves, high safety, and environmental friendliness. Utilizing an aqueous electrolyte, it fundamentally solves the flammability problem of organic batteries, and offers high theoretical capacity and low manufacturing costs. It shows broad prospects in large-scale energy storage and wearable devices, and is expected to become an important supplement to lithium-ion batteries, driving energy structure transformation.

[0003] However, zinc anodes face three major challenges in practical applications: first, zinc dendrite formation, where uneven deposition can puncture the separator and cause short circuits; second, hydrogen evolution reaction, where zinc reacts with water to produce hydrogen gas, leading to loss of active materials and safety hazards; and third, electrode deformation and irreversible side reactions (such as the formation of zinc oxide), resulting in capacity decay and increased internal resistance. These interfacial side reactions and uncontrolled deposition problems severely restrict the cycle life and commercialization of zinc batteries.

[0004] In existing technologies, highly conductive metal oxide coatings (such as titanium dioxide) are a promising strategy for modifying zinc anodes. This coating, as a multifunctional protective layer, primarily plays three roles: first, it acts as a dense physical barrier, inhibiting side reactions such as corrosion and hydrogen evolution; second, its excellent conductivity guides the uniform deposition of zinc ions, preventing dendrite growth; and third, it maintains interface integrity through good mechanical and chemical stability, thereby significantly improving battery cycle life and coulombic efficiency. However, in related technologies, the protective layer is often prepared by a blade coating method. This method requires mixing conductive metal oxide particles with an insulating polymer binder (such as polyvinylidene fluoride) to form a slurry, which is then coated onto a zinc substrate and cured. However, since the binder inevitably coats the conductive particles during curing, its insulating properties hinder electron transport paths, weakening the coating's high conductivity advantage. Furthermore, this method relies on the rheological properties of the slurry, making it difficult to precisely control the coating's thickness distribution, porosity, and microscopic uniformity, and the mechanical bonding strength between the coating and the substrate is limited.

[0005] The aforementioned defects lead to conductivity degradation, structural instability, and interface peeling in the protective layer during long-term charge-discharge cycles, which in turn makes it unable to effectively suppress side reactions and dendrite growth, thus limiting the cycle life and reliability of zinc-ion batteries. With the increasing demand for high energy density and long-cycle stability in energy storage systems, developing more efficient negative electrode protective layer construction technologies has become a core issue that urgently needs to be addressed. Summary of the Invention

[0006] In view of this, the present invention aims to at least partially solve one of the technical problems in the related art. To this end, the present invention provides a zinc metal anode, which prepares highly conductive indium tin oxide (ITO) nanorods through microwave solvothermal synthesis and high-temperature calcination, and constructs a binder-free, structurally controllable protective layer on the surface of zinc foil using electrophoretic deposition technology.

[0007] To solve the above-mentioned technical problems, the present invention is implemented as follows:

[0008] According to one aspect of the present invention, a zinc metal anode is provided, comprising: a zinc metal substrate, and a coating covering the surface of the zinc metal substrate; the coating comprising a conductive metal oxide;

[0009] The coating is formed on the zinc metal substrate by deposition.

[0010] In some of these embodiments, the conductive metal oxide is indium tin oxide (ITO).

[0011] In some of these embodiments, the indium tin oxide has a microstructure of nanorods.

[0012] In some embodiments, the nanorods have a length of 50 nm to 300 nm and a width of 10 nm to 50 nm.

[0013] The short nanorods can form line contacts or even surface contacts, greatly increasing the contact area and enabling electrons to travel long distances as in continuous materials. This significantly reduces interfacial contact resistance and thus greatly improves the overall conductivity of the network.

[0014] In some embodiments, the coating thickness is 3 μm to 5 μm.

[0015] In some embodiments, this method of using the conductive metal oxide includes the following steps:

[0016] (1) Indium source and tin source are added to solvent and reacted to obtain intermediate product; during the crystal nucleus growth process, Sn 4+ Begins to replace In in the In2O3 lattice 3+ Because it has an extra positive charge, it contributes free electrons, laying the foundation for high conductivity.

[0017] (2) Subsequently, the intermediate product from step (1) is ground and calcined to obtain a conductive metal oxide. The calcined product is Sn. 4+ Provides kinetic energy, allowing it to diffuse fully and uniformly replace In. 3+This process forms an atomically uniform indium tin oxide solid solution, which is key to achieving excellent conductivity. Simultaneously, high-temperature decomposition effectively removes anions and organic residues, ultimately yielding high-purity ITO material.

[0018] In some of these embodiments, the tin source comprises tetra-tert-butyltin and / or tin acetylacetonate.

[0019] In some embodiments, the tin source accounts for 5% to 15% of the total molar percentage of the indium source and the tin source.

[0020] In some embodiments, the indium source includes indium acetylacetone and / or indium acetate;

[0021] In some of these embodiments, the solvent in step (1) is a mixture of benzylamine and benzyl alcohol.

[0022] In some embodiments, the volume ratio of benzylamine to benzyl alcohol is 1:1 to 1:3.

[0023] In some of these embodiments, the reaction in step (1) is carried out by microwave heating; preferably, the temperature of the microwave heating is 165°C to 205°C and the microwave heating time is 40 min to 70 min.

[0024] In some of these embodiments, the calcination temperature in step (2) is 400℃~600℃; the calcination atmosphere is air; and the calcination holding time is 2h~4h.

[0025] In some of these embodiments, the conductive metal oxide is formed on the zinc metal substrate by electrophoretic deposition.

[0026] In some of these embodiments, the electrophoretic deposition process includes:

[0027] S1: First, the conductive metal oxide and the charging agent are dispersed in a polar organic solvent to obtain a suspension;

[0028] S2: An electrode system is constructed using a zinc metal substrate as the cathode and a platinum sheet as the anode, and deposition is carried out under a DC electric field;

[0029] S3: After deposition, the sample is heat-treated to obtain a zinc metal anode.

[0030] In some of these embodiments, the mass concentration of the conductive metal oxide is A g / L; the deposition conditions include: a deposition voltage of BV and a deposition time of C min;

[0031] The electrophoretic deposition condition satisfies: 200 ≤ A 2 B C≤650;

[0032] Among them, A satisfies 0.5~2.0; B satisfies 10~90; and C satisfies 0.5~10.

[0033] It should be noted that A, B and C do not include units.

[0034] In some embodiments, the charging agent in step S1 includes elemental iodine.

[0035] In some embodiments, the polar organic solvent in step S1 includes at least one of acetone, butanone, acetylacetone, and acetonitrile.

[0036] In some embodiments, the concentration of the charging agent is 0.5 mM to 1.5 mM.

[0037] In some of these embodiments, ultrasound assistance is performed during the preparation of the suspension in step S1.

[0038] In some embodiments, the heat treatment conditions of step S3 include segmented heat treatment under an inert atmosphere: first stage: temperature 60℃~70℃, time 1 h~2 h; second stage: temperature 100℃~120℃, time 2 h~4 h.

[0039] The purpose of heat treatment at 60℃~70℃ is to quickly remove most of the solvent and avoid rapid shrinkage; the purpose of heat treatment at 100℃~120℃ is to remove iodine residue, release internal stress, and stabilize the environment.

[0040] According to another aspect of the present invention, a zinc-ion battery is provided, comprising the above-described zinc metal negative electrode, positive electrode, and electrolyte.

[0041] In some of these embodiments, the positive electrode comprises vanadium pentoxide.

[0042] In some of these embodiments, the electrolyte is an aqueous electrolyte.

[0043] In some of these embodiments, the electrolyte comprises a zinc salt.

[0044] In some embodiments, the zinc salt includes one or more of zinc sulfate, zinc acetate, and zinc trifluoromethanesulfonate.

[0045] Implementing the technical solution of the present invention has at least the following beneficial effects:

[0046] 1. ITO nanorods, with their high carrier concentration and three-dimensional network structure generated by tin doping, achieve efficient electron and ion transport, effectively guide uniform zinc deposition, and suppress dendrite growth.

[0047] 2. The electrophoretic deposition process does not require insulating binders, thus avoiding the loss of conductivity. At the same time, by adjusting the voltage and time, the coating thickness and uniformity can be precisely controlled to form a dense porous structure, which has both excellent ion permeability and mechanical stability.

[0048] 3. This protective layer acts as a physical barrier, significantly inhibiting side reactions such as corrosion and hydrogen evolution. It also strengthens the interfacial bonding force through low-temperature heat treatment, thereby improving the overall cycle life, coulombic efficiency, and rate performance of the zinc anode, providing a reliable solution for the practical application of zinc-ion batteries. Attached Figure Description

[0049] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0050] Figure 1 This is a morphology diagram of the indium tin oxide nanorods synthesized in Example 1.

[0051] Figure 2 This is a comparison of the morphology of the zinc anode after 100 hours of cycling between Example 1 and Comparative Example 9.

[0052] The accompanying drawings have illustrated specific embodiments of the invention, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the invention in any way, but rather to illustrate the concept of the invention to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0053] The present application will be further described below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the present application.

[0054] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges or individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0055] In the description of this application, "A and / or B" can include any of the cases of A alone, B alone, or A and B, where A and B are merely examples and can be any technical feature connected by "and / or" in this application.

[0056] Unless otherwise specified, the terms "comprising" and "including" as used in this invention can be open-ended or closed-ended. For example, "comprising" and "including" can mean that other components not listed may also be included, or that only the listed components may be included.

[0057] Unless otherwise specified, all embodiments and optional embodiments of the present invention can be combined with each other to form new technical solutions.

[0058] Unless otherwise specified, all technical features and optional technical features of this invention can be combined to form new technical solutions.

[0059] Unless otherwise specified, all steps of the present invention may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the mention that the method may also include step (c) indicates that step (c) may be added to the method in any order; for example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0060] Currently, the inventors of this invention have discovered during the research and development process that highly conductive metal oxide coatings (such as titanium dioxide) are a promising strategy for modifying zinc anodes. The actual effectiveness of this strategy is highly dependent on the preparation process. Traditional blade coating methods exhibit significant limitations: this method requires mixing active powder with an insulating polymer binder (such as PVDF) to form a slurry. After curing, the binder coats the conductive particles, forming a transport barrier and severely weakening the coating's high conductivity advantage. Furthermore, this method makes it difficult to precisely control the coating's thickness, porosity, and uniformity, and the mechanical bonding between the coating and the substrate is weak, making it prone to peeling during long-term cycling, leading to loss of protective function.

[0061] Building upon this, the inventors of this invention prepared highly conductive indium tin oxide (ITO) nanorods through a combination of microwave solvothermal synthesis and high-temperature calcination, and then utilized electrophoretic deposition to construct a binder-free, structurally controllable protective layer on the surface of zinc foil. Specifically, this invention employs the following technical solution:

[0062] According to one aspect of the present invention, a zinc metal anode is provided, comprising: a zinc metal substrate, and a coating covering the surface of the zinc metal substrate; the coating comprising a conductive metal oxide;

[0063] The coating is formed on the zinc metal substrate in a manner that does not rely on organic polymer binders.

[0064] In some embodiments, the zinc metal substrate comprises zinc foil, which is pretreated by sanding, cleaning with dilute acid (such as 0.1M HCl) or ethanol in sequence to remove oxide layers and oil stains, ensuring surface cleanliness and good wettability.

[0065] In some of these embodiments, the conductive metal oxide is indium tin oxide (ITO).

[0066] In some of these embodiments, the indium tin oxide has a microstructure of nanorods.

[0067] In some embodiments, the nanorods have a length of 50 nm to 300 nm and a width of 10 nm to 50 nm.

[0068] The short nanorods can form line contacts or even surface contacts, greatly increasing the contact area and enabling electrons to travel long distances as in continuous materials. This significantly reduces interfacial contact resistance and thus greatly improves the overall conductivity of the network.

[0069] In some of these embodiments, the coating thickness is 3 μm to 5 μm.

[0070] This coating effectively suppresses side reactions through physical isolation. At the same time, thanks to the high carrier concentration obtained by tin doping, combined with the three-dimensional conductive network constructed by nanorods, it achieves efficient electron conduction and ion transport, guiding the uniform deposition of zinc ions.

[0071] In some embodiments, this method of using the conductive metal oxide includes the following steps:

[0072] (1) Indium source and tin source are added to solvent and reacted to obtain intermediate product; during the crystal nucleus growth process, Sn 4+ Begins to replace In in the In2O3 lattice 3+ Because it has an extra positive charge, it contributes free electrons, laying the foundation for high conductivity.

[0073] (2) Subsequently, the intermediate product from step (1) is ground and calcined to obtain a conductive metal oxide. The calcined product is Sn. 4+ Provides kinetic energy, allowing it to diffuse fully and uniformly replace In. 3+ This process forms an atomically uniform indium tin oxide solid solution, which is key to achieving excellent conductivity. Simultaneously, high-temperature decomposition effectively removes anions and organic residues, ultimately yielding high-purity ITO material.

[0074] In some of these embodiments, the tin source comprises tetra-tert-butyltin and / or tin acetylacetonate.

[0075] In some embodiments, the tin source accounts for 5% to 15% of the total molar percentage of the indium source and the tin source.

[0076] In some embodiments, the tin source comprises 8% to 12% of the total molar amount of tetra-tert-butyltin and indium acetylacetonate.

[0077] When the tin content is too low (<5%), the carrier concentration is insufficient and the material conductivity is low; when the tin content is too high (>15%), it will exceed the solid solubility, generate SnO2 impurity phase and cause lattice distortion, the carrier mobility will decrease sharply, and the conductivity will deteriorate.

[0078] In some embodiments, the indium source includes indium acetylacetone and / or indium acetate;

[0079] In some of these embodiments, the solvent in step (1) is a mixture of benzylamine and benzyl alcohol.

[0080] In some embodiments, the volume ratio of benzylamine to benzyl alcohol is 1:1 to 1:3.

[0081] In some of these embodiments, the reaction in step (1) is carried out by microwave heating; preferably, the temperature of the microwave heating is 165°C to 205°C and the time of the microwave heating is 40 min to 70 min.

[0082] In some embodiments, the calcination temperature in step (2) is 400℃~600℃. The calcination atmosphere is air, and the calcination holding time is 2h~4h. If the temperature is too low, the precursor cannot fully crystallize and form a complete solid solution, resulting in poor crystallinity, uneven tin doping, and residual impurities, which significantly degrades the intrinsic conductivity of the material. If the temperature is too high, it will cause excessive sintering and coarsening of the particles, a sharp decrease in specific surface area, and may also lead to the segregation and volatilization of tin, destroying the homogeneity of the solid solution.

[0083] In some of these embodiments, the conductive metal oxide is formed on the zinc metal substrate by electrophoretic deposition.

[0084] In some of these embodiments, the electrophoretic deposition process includes:

[0085] S1: First, the conductive metal oxide and the charging agent are dispersed in a polar organic solvent to obtain a suspension;

[0086] S2: An electrode system is constructed using a zinc metal substrate as the cathode and a platinum sheet as the anode, and deposition is carried out under a DC electric field;

[0087] S3: After deposition, the sample is heat-treated to obtain a zinc metal anode.

[0088] Mechanism: The reaction of iodine with solvent produces CH3COCH2I + I + ITO particles are positively charged by adsorption of cations onto their surface. Under the influence of an electric field, the positively charged ITO particles migrate towards the negatively charged cathode, eventually shedding the solvation layer and densely depositing onto the zinc foil surface, forming a dense and uniform coating. Heat treatment effectively removes residual solvents, enhancing the coating's cohesion and adhesion to the substrate.

[0089] In some of these embodiments, the mass concentration of the conductive metal oxide is A g / L; the deposition conditions include: a deposition voltage of BV and a deposition time of C min;

[0090] The electrophoretic deposition condition satisfies: 200 ≤ A 2 B C≤650;

[0091] Among them, A satisfies 0.5~2.0; B satisfies 10~90; and C satisfies 0.5~10.

[0092] It should be noted that A, B and C do not include units.

[0093] When the concentration of A is too low, deposition is slow; when the concentration of A is too high, aggregation is likely to occur.

[0094] When the voltage (B) is too low, the driving force of the electric field is insufficient to effectively overcome the Brownian motion of the particles, resulting in an extremely slow deposition rate or even failure to occur, making it difficult to form a complete coating. On the other hand, when the voltage (B) is too high, the nanorods are pulled too quickly to the electrode surface, preventing orderly stacking and resulting in a loose, porous powder layer with poor adhesion. At the same time, nodular rough deposits are prone to appear in high current density areas such as the electrode edges.

[0095] When the deposition time C is too short, the nanorods cannot migrate sufficiently to the zinc foil surface, resulting in incomplete coating coverage and insufficient thickness. This discontinuous coating contains defect sites, which will cause uneven zinc deposition and accelerate dendrite growth, while failing to effectively isolate side reactions. Conversely, if the deposition time C is too long, an excessively thick coating will form, with significantly increased internal stress. This makes it prone to cracking and peeling during drying or battery cycling. At the same time, an excessively thick layer will increase the ion and electron transport impedance, impairing the battery's rate performance.

[0096] In some embodiments, the charging agent in step S1 includes elemental iodine.

[0097] In some embodiments, the polar organic solvent in step S1 includes at least one of acetone, butanone, acetylacetone, and acetonitrile.

[0098] In some embodiments, the concentration of the charging agent is 0.5~1.5mM.

[0099] In some embodiments, ultrasound assistance is used in the preparation of the suspension in step S1.

[0100] In some embodiments, the heat treatment conditions of step S3 include segmented heat treatment under an inert atmosphere: first stage: temperature 60℃~70℃, time 1 h~2 h; second stage: temperature 100℃~120℃, time 2 h~4 h.

[0101] The purpose of heat treatment at 60℃~70℃ is to quickly remove most of the solvent and avoid rapid shrinkage; the purpose of heat treatment at 100℃~120℃ is to remove iodine residue, release internal stress, and stabilize the environment.

[0102] After low-temperature heat treatment, the interfacial bonding force is further enhanced, and an ideal protective layer with dense, porous, highly conductive and strongly bonded structure is finally obtained.

[0103] According to another aspect of the present invention, a zinc-ion battery is provided, comprising the above-described zinc metal negative electrode, positive electrode, and electrolyte.

[0104] In some of these embodiments, the positive electrode comprises vanadium pentoxide.

[0105] In some of these embodiments, the electrolyte is an aqueous electrolyte.

[0106] In some of these embodiments, the electrolyte comprises a zinc salt.

[0107] In some embodiments, the zinc salt includes one or more of zinc sulfate, zinc acetate, and zinc trifluoromethanesulfonate.

[0108] In a specific embodiment of the present invention, the battery can be a battery module assembled from individual battery cells. The battery module can contain one or more battery cells, the specific number of which can be selected by those skilled in the art based on the application and capacity of the battery module. In the battery module, the multiple battery cells can be arranged sequentially along the length of the battery module; of course, they can also be arranged in any other arbitrary manner. Furthermore, the multiple battery cells can be fixed using fasteners. The battery module may also include a housing with a receiving space, in which the multiple battery cells are received.

[0109] In the description of this invention, "a plurality of" means two or more.

[0110] In a specific embodiment of the present invention, the battery can also be a battery pack assembled from the aforementioned battery modules. The battery pack may contain one or more battery modules, and the specific number can be selected by those skilled in the art based on the application and capacity of the battery pack. Specifically, the battery pack may include a battery box and multiple battery modules disposed within the battery box; the battery box includes an upper box and a lower box, the upper box covering the lower box and forming a closed space for accommodating the battery modules. The multiple battery modules can be arranged in the battery box in any manner.

[0111] According to another aspect of the present invention, an electrical device is provided, comprising the battery described in the above-described technical solution. Thus, the electrical device possesses all the features and advantages of the battery described in the above-described technical solution, which will not be repeated here. Specifically, the battery can serve as a power source for the electrical device, or as an energy storage unit for the electrical device. The electrical device may include, but is not limited to, mobile devices (e.g., mobile phones, laptops), electric vehicles (e.g., pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks), electric trains, ships and satellites, and energy storage systems.

[0112] The present application will be described in detail below with reference to the accompanying drawings and embodiments. However, the implementation and protection of the present invention are not limited thereto. The following embodiments are only some embodiments of the present application and are not intended to limit the present application. Where specific techniques or conditions are not specified in the embodiments, they shall be performed in accordance with the techniques or conditions described in the literature in this field or in accordance with the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained commercially.

[0113] Example 1

[0114] A method for preparing a zinc metal negative electrode includes the following steps:

[0115] (1) Preparation of indium tin oxide: Benzylamine / benzyl alcohol were mixed at a volume ratio of 1:2 to obtain a first solution. 90 mmol of indium acetylacetonate and 10 mmol of tetra-tert-butyltin were weighed and added to the first solution and stirred until homogeneous to obtain a second solution. The second solution was placed in a microwave reactor and heated at 185 °C for 55 min. After the reaction was completed, an intermediate product was obtained by centrifugation, washing, and drying. The intermediate product was calcined in air and kept at 510 °C for 3 h to obtain the final product, indium tin oxide nanorods.

[0116] (2) Preparation of zinc metal anode: 0.12 g of indium tin oxide and 0.1 mM iodine were dispersed together in 100 mL of acetone and ultrasonically homogenized to obtain a third solution. Zinc foil and platinum sheet were inserted into the third solution to construct a two-electrode system with zinc foil as cathode and platinum sheet as anode, and deposition was carried out at 55 V for 5 min. Subsequently, the deposited zinc foil was heat-treated at 70 °C for 5 h to obtain a zinc metal anode (Zn@ITO) containing an indium tin oxide metal oxide coating.

[0117] Regarding the determination of deposition time: 200 ≤ A 2 B C≤650; where A=1.2, B=55, then the range of C is 2.5min~8.2min, and in this embodiment, 5min is selected.

[0118] (3) Battery assembly: The zinc-ion battery was assembled in the following order: negative electrode (Zn@ITO), separator (GF / D), electrolyte (2M zinc sulfate solution), positive electrode (V2O5), gasket, and spring contact. The battery casing model used was CR2032. The cycle performance of the zinc-ion battery was tested at a current density of 5A / g at room temperature.

[0119] Figure 1 This is a morphology image of the indium tin oxide nanorods synthesized in Example 1. Figure 1 It can be seen that the length of the indium tin oxide nanorods is 50 nm to 200 nm and the width is 20 nm to 40 nm. The rod-shaped structure is beneficial for the subsequent construction of a three-dimensional conductive network.

[0120] Figure 2 The images show a comparison of the zinc anode morphology after 100 hours of cycling between Example 1 and Comparative Example 9. The comparison shows that the introduction of indium tin oxide nanorods effectively improves electron conduction and ion transport rates, while also guiding the uniform deposition of zinc ions, ultimately forming a uniform and flat zinc deposition (e.g., ...). Figure 2 (As shown in the middle left figure).

[0121] Example 2

[0122] Except for changing the amount of indium acetylacetone to 92 mmol and the amount of tetra-tert-butyltin to 8 mmol, all other steps are the same as in Example 1.

[0123] Example 3

[0124] Except for changing the amount of indium acetylacetone to 88 mmol and the amount of tetra-tert-butyltin to 12 mmol, all other steps are the same as in Example 1.

[0125] Example 4

[0126] Except for changing the high-temperature calcination temperature to 475°C, all other steps are the same as in Example 1.

[0127] Example 5

[0128] Except for changing the high-temperature calcination temperature to 550°C, all other steps are the same as in Example 1.

[0129] Example 6

[0130] Except for changing the ITO metal oxide mass concentration to 1.0 g / L, i.e. adding 0.10 g of indium tin oxide, all other steps are the same as in Example 1.

[0131] Example 7

[0132] Except for changing the ITO metal oxide mass concentration to 1.5 g / L, i.e. adding 0.15 g of indium tin oxide, all other steps are the same as in Example 1.

[0133] Example 8

[0134] Except for changing the deposition voltage in step (2) to 30V, the other steps are the same as in Example 1.

[0135] Example 9

[0136] Except for changing the deposition voltage in step (2) to 70V, the other steps are the same as in Example 1.

[0137] Example 10

[0138] Except for changing the deposition time in step (2) to 3 minutes, all other steps are the same as in Example 1.

[0139] Example 11

[0140] Except for changing the deposition time in step (2) to 7 minutes, all other steps are the same as in Example 1.

[0141] Comparative Example 1

[0142] Except for changing the amount of indium acetylacetone to 98 mmol and the amount of tetra-tert-butyltin to 2 mmol, all other steps are the same as in Example 1.

[0143] Comparative Example 2

[0144] Except for changing the amount of indium acetylacetone to 83 mmol and the amount of tetra-tert-butyltin to 17 mmol, all other steps are the same as in Example 1.

[0145] Comparative Example 3

[0146] Except for changing the high-temperature calcination temperature to 350°C, all other steps are the same as in Example 1.

[0147] Comparative Example 4

[0148] Except for changing the high-temperature calcination temperature to 650°C, all other steps are the same as in Example 1.

[0149] Comparative Example 5

[0150] Except for changing the ITO metal oxide mass concentration to 0.2 g / L, i.e. adding 0.02 g of indium tin oxide, all other steps are the same as in Example 1.

[0151] Comparative Example 6

[0152] Except for changing the ITO metal oxide mass concentration to 2.2 g / L, i.e. adding 0.22 g of indium tin oxide, all other steps are the same as in Example 1.

[0153] Comparative Example 7

[0154] Except for changing the deposition voltage in step (2) to 5V, the other steps are the same as in Example 1.

[0155] Comparative Example 8

[0156] Except for changing the deposition voltage in step (2) to 100V, the other steps are the same as in Example 1.

[0157] Comparative Example 9

[0158] Except for changing the deposition time in step (2) to 0.1 min, all other steps are the same as in Example 1.

[0159] Comparative Example 10

[0160] Except for changing the deposition time in step (2) to 11 min, all other steps are the same as in Example 1.

[0161] Comparative Example 11

[0162] The negative electrode uses commercial zinc foil without indium tin oxide coating, and the remaining steps are consistent with those in Example 1.

[0163] Test method:

[0164] Symmetrical cell cycle life: At room temperature (25°C), the symmetric cell cycle life is 5 mA cm⁻¹. -2 5mAh cm -2 The battery was subjected to charge-discharge cycles under the test conditions, and the cycle life was recorded.

[0165] Full cell capacity retention after 3000 cycles: At room temperature of 25°C, the full cell was charged and discharged at a current density of 5 A / g, and the battery capacity retention was recorded after 3000 cycles.

[0166] Test results:

[0167] Table 1. Performance comparison of zinc-ion batteries prepared in Examples 1-11 and Comparative Examples 1-11

[0168]

[0169] As can be seen from Example 1 and Comparative Examples 1 and 2, although the deposited coating meets the requirements, the carrier concentration is insufficient and the material conductivity is low when the tin content is too low (<5%); when the tin content is too high (>15%), it will exceed the solid solubility, generate SnO2 impurity phase and cause lattice distortion, the carrier mobility will decrease sharply, and the conductivity will deteriorate.

[0170] As can be seen from Examples 1 and Comparative Examples 3 and 4, when the temperature is too low, the precursor cannot fully crystallize and form a complete solid solution, resulting in poor crystallinity, uneven tin doping, and residual impurities, which significantly degrades the intrinsic conductivity of the material. On the other hand, excessively high temperatures cause excessive sintering and coarsening of the particles, a sharp decrease in specific surface area, and may also lead to the segregation and volatilization of tin, thus destroying the homogeneity of the solid solution.

[0171] Comparative examples 5-10 show that A, B, and C do not satisfy 200 ≤ A 2 B C≤650, therefore the effect is poor.

[0172] As can be seen from Examples 1 and Comparative Examples 7 and 8, when the voltage is too low, the driving force of the electric field is insufficient to effectively overcome the Brownian motion of the particles, resulting in an extremely slow deposition rate or even failure to occur, making it difficult to form a completely covered coating. On the other hand, when the voltage is too high, the nanorods are pulled too quickly to the electrode surface, failing to achieve orderly stacking, thus forming a loose, porous powder layer with poor bonding. At the same time, nodular rough deposits are prone to appear in high current density areas such as the electrode edges.

[0173] As shown in Example 1 and Comparative Examples 9 and 10, when the deposition time is too short, the nanorods cannot fully migrate to the zinc foil surface, resulting in incomplete coating coverage and insufficient thickness. This discontinuous coating contains defect sites, which will cause uneven zinc deposition and accelerate dendrite growth, while failing to effectively isolate side reactions. Conversely, if the deposition time is too long, an excessively thick coating will be formed, with significantly increased internal stress. This makes it prone to cracking and peeling during drying or battery cycling. At the same time, an excessively thick layer will increase the ion and electron transport impedance, impairing the battery rate performance.

[0174] The parts of this invention not described in detail are techniques known to those skilled in the art.

[0175] The basic principles of the present invention have been described above with reference to specific embodiments. However, it should be noted that the advantages, benefits, and effects mentioned in the present invention are merely examples and not limitations, and should not be considered as essential features of each embodiment of the present invention. Furthermore, the specific details disclosed above are for illustrative and facilitative purposes only, and are not limitations. These details do not limit the present invention to the necessity of employing the aforementioned specific details.

[0176] In the foregoing description of this specification, the reference to the term "in some of these embodiments" indicates that a specific feature, structure, material, or characteristic described in connection with that embodiment is included in at least one embodiment of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples, without contradiction. Additionally, it should be noted that in this specification, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features.

[0177] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A zinc metal negative electrode, characterized in that, include: A zinc metal substrate, and a coating covering the surface of the zinc metal substrate; The coating comprises a conductive metal oxide; The conductive metal oxide is indium tin oxide; The microstructure of the indium tin oxide is a nanorod; The method for preparing the conductive metal oxide includes the following steps: (1) Add indium source and tin source to solvent, react to obtain intermediate product; (2) Grind and calcine the intermediate product from step (1) to obtain a conductive metal oxide; The tin source accounts for 5% to 15% of the total molar percentage of the indium source and the tin source; The reaction in step (1) is a microwave solvothermal reaction; the calcination temperature in step (2) is 400℃~600℃; The conductive metal oxide is formed on the zinc metal substrate by electrophoretic deposition; The conditions for electrophoretic deposition include: a deposition voltage of BV, a deposition time of C min, and a mass concentration of A g / L for the conductive metal oxide. The electrophoretic deposition condition satisfies: 200 ≤ A 2 B C≤650; Among them, A satisfies 0.5~2.0; B satisfies 10~90; and C satisfies 0.5~10.

2. The zinc metal negative electrode according to claim 1, characterized in that, The thickness of the coating is 3μm to 5μm; And / or, the length of the nanorod is 50~300nm and the width is 10~50nm.

3. The zinc metal negative electrode according to claim 1, characterized in that, The tin source includes tetra-tert-butyltin and / or tin acetylacetone; And / or, the indium source includes indium acetylacetone and / or indium acetate.

4. The zinc metal negative electrode according to claim 3, characterized in that, The solvent in step (1) is a mixture of benzylamine and benzyl alcohol; And / or, the temperature of the microwave solvothermal reaction in step (1) is 165℃~205℃ and the time is 40min~70min; And / or, the calcination atmosphere in step (2) is air, and the calcination holding time is 2h~4h.

5. The zinc metal negative electrode according to claim 1, characterized in that, The electrophoretic deposition process includes: S1: First, the conductive metal oxide and the charging agent are dispersed in a polar organic solvent to obtain a suspension; S2: An electrode system is constructed using a zinc metal substrate as the cathode and a platinum sheet as the anode, and deposition is carried out under a DC electric field; S3: After deposition, the sample is heat-treated to obtain a zinc metal anode.

6. The zinc metal negative electrode according to claim 5, characterized in that, The charging agent in step S1 includes elemental iodine; And / or, the polar organic solvent in step S1 includes at least one of acetone, butanone, acetylacetone, and acetonitrile; And / or, the concentration of the charging agent is: 0.5 mM~1.5 mM; And / or, ultrasound assistance is performed during the preparation of the suspension in step S1; And / or, the heat treatment conditions in step S3 include segmented heat treatment under an inert atmosphere: first stage: temperature 60℃~70℃, time 1 h~2 h; second stage: temperature 100℃~120℃, time 2 h~4 h.

7. A zinc-ion battery, characterized in that, It includes a positive electrode, a negative electrode, and an electrolyte; the negative electrode includes the zinc metal negative electrode according to any one of claims 1 to 6.

8. The zinc-ion battery according to claim 7, characterized in that, The positive electrode comprises vanadium pentoxide; And / or, the electrolyte is an aqueous electrolyte; the electrolyte includes zinc salts.

9. The zinc-ion battery according to claim 8, characterized in that, The zinc salt includes one or more of zinc sulfate, zinc acetate, and zinc trifluoromethanesulfonate.

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