Mesoporous conductive MOF modified zinc negative electrode and preparation method and application thereof

Abstract

The invention relates to the field of electrochemical energy storage, in particular to a mesoporous conductive MOF modified zinc negative electrode and a preparation method and application thereof. The mesoporous conductive MOF modified zinc negative electrode comprises a metal zinc foil and a mesoporous conductive MOF coating, the zinc negative electrode material disclosed by the invention has the capabilities of lightening and thinning, high wettability of aqueous electrolyte, promotion of ion desolvation, acceleration of ion transmission and the like, dendritic crystal growth is inhibited from the source, the porous structure binds water molecules to reduce activity, and the corrosion inhibition function of the additive is matched, so that corrosion hydrogen evolution of a zinc negative electrode is greatly reduced, and the service life of the zinc negative electrode is prolonged. Core pain points of dendritic crystal short circuit and corrosion failure of a traditional zinc negative electrode are solved, and the cycle life of the battery is remarkably prolonged; according to the invention, through the modification of the mesoporous conductive MOF coating, the high conductivity and the mesoporous channel form an efficient electron-ion transmission network, and the continuous ion channel is constructed in cooperation with the excellent electrolyte wettability of the interface, so that the internal resistance of the electrode and the charge transfer impedance are synergistically reduced, thereby significantly improving the rate capability and the cycle stability of the battery.

Description

Technical Field

[0001] This invention relates to the field of electrochemical energy storage, and in particular to a mesoporous conductive MOF-modified zinc anode, its preparation method, and its application. Background Technology

[0002] Aqueous zinc-ion batteries have become an ideal candidate battery system for large-scale energy storage and portable electronic devices due to their advantages such as high theoretical capacity (the theoretical specific capacity of zinc is 820 mAh / g), safe and non-toxic electrolyte, abundant zinc resources, low cost, and good environmental compatibility. However, zinc anodes in aqueous environments face three major problems: First, zinc dendrite growth. During zinc deposition, metallic zinc easily forms irregular dendrites on the anode surface. These dendrites can penetrate the separator, causing a short circuit between the positive and negative electrodes and leading to battery failure. Second, corrosion, hydrogen evolution, and passivation of the zinc anode. Zinc anodes are prone to hydrogen evolution corrosion during electrodeposition and storage, which not only consumes zinc active materials and electrolyte, reducing coulombic efficiency, but also leads to the formation of a loose and porous corrosion layer on the electrode surface, hindering ion and electron transport. Third, high interfacial impedance. The poor interfacial compatibility between the traditional zinc anode surface and the electrolyte, coupled with the insulating properties of the passivation layer, results in a significant increase in interfacial impedance, leading to a substantial decrease in battery rate performance (fast charge and discharge capability). These problems severely restrict the industrial application of aqueous zinc batteries.

[0003] To address the aforementioned issues, existing technologies have proposed various surface modification strategies for zinc anodes, but these strategies still have significant drawbacks. For example, coating the zinc surface with carbon materials (graphene, carbon nanotubes) can improve conductivity, but the dense structure of carbon materials can hinder zinc ion transport. Coating with inorganic materials such as metal oxides (e.g., Al2O3, TiO2) can block dendrites to some extent, but inorganic materials have poor conductivity (conductivity <10). -5 The low conductivity (S / m) exacerbates electron transport lag, and the weak interfacial adhesion between the coating and zinc foil makes it prone to peeling. Modification with MOF materials (such as UIO-66, ZIF-8, etc.) is possible, but existing MOFs used for zinc anode modification are all microporous structures (pore size < 2nm) and lack conductivity. While they can regulate ion transport, they cannot solve the electron conduction problem. Furthermore, the small pore size of the microporous structure makes it susceptible to blockage by byproducts, leading to functional deactivation and still resulting in poor rate and cycle performance. For example, patent 2020108652691 discloses a zinc anode modified with MOF, but the ZIF-8 used is a microporous MOF (pore size 1.1nm) with a conductivity of only 10. -5 The S / m ratio cannot simultaneously achieve both ion transport and electron conduction. Therefore, developing a zinc anode modification material that combines mesoporous structure (facilitating ion diffusion), high conductivity (promoting electron transport), and strong interfacial bonding (preventing coating peeling) is crucial to overcoming the performance bottleneck of aqueous zinc batteries. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing technologies by providing a mesoporous conductive MOF-modified zinc anode, its preparation method, and its application.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A first aspect of the present invention is to provide a mesoporous conductive MOF modified zinc anode, comprising: a zinc foil and a mesoporous conductive MOF coating applied to both sides of the zinc foil;

[0007] The mesoporous conductive MOF coating, by weight, comprises: 50-90 parts of mesoporous ZnHHTP conductive MOF nanomaterials, 5-30 parts of binder, and 0-20 parts of additives; the mesoporous ZnHHTP conductive MOF nanomaterials have mesoporous channels with a pore size of 2-20 nm and a pore volume of 0.3-0.8 cm³. 3 / g, conductivity greater than 0.05S / m.

[0008] By selecting mesoporous ZnHHTP MOF nanomaterials as mesoporous conductive MOF nanomaterials, it is beneficial to utilize the homogenization of the pore structure and accelerate ion transport. The pore size of the mesoporous ZnHHTP MOF is concentrated in the range of 2-20 nm, which is beneficial for accelerating desolvation, shortening the ion migration path, improving rate performance, and the uniform pore size can guide the directional deposition of zinc ions and reduce zinc dendrite formation. Suitable pore size can limit electrolyte side reactions and improve coulombic efficiency; the pore volume distribution of the mesoporous conductive MOF nanomaterial is 0.3-0.8 cm³. 3 / g, the high pore volume provides a larger capacity, allowing more zinc to be deposited uniformly and improving cycle stability; the mesoporous conductive MOF nanomaterial has a conductivity of more than 0.05 S / m. The high conductivity reduces the internal resistance of the electrode, promotes the rapid transfer of electrons from the current collector to the reaction interface, reduces polarization, improves rate performance, avoids current concentration, and promotes uniform deposition of zinc ions.

[0009] Preferably, the thickness of each layer of the mesoporous conductive MOF coating is independently 0.1-30 μm, and the areal density is independently 0.2-3 mg / cm³. 2 .

[0010] By controlling the coating thickness, the thickness and loading of the mesoporous conductive MOF zinc anode material are controlled. While ensuring the beneficial effects of low electrode internal resistance and uniform zinc deposition of the modified zinc anode material, the thickness of the mesoporous ZnHHTP conductive MOF coating is as thin as possible and the coating surface loading is as low as possible. This ensures the lightweight characteristics of the zinc anode, which is conducive to assembling more electrode materials in the battery device, thereby improving the overall energy density of the battery device.

[0011] Preferably, the mesoporous conductive MOF coating has a wetting angle of less than 60° to water.

[0012] Excellent wetting properties allow the electrolyte to uniformly cover the negative electrode surface and penetrate into the pores of the modified coating, forming continuous ion transport channels. This reduces Zn... 2+ This reduces migration resistance, lowers charge transfer impedance, and improves battery rate performance. Furthermore, good wetting properties prevent ion transport lag and uneven zinc ion concentration at the interface caused by localized liquid shortages, thus guiding orderly zinc deposition, reducing dendrite formation at the source, preventing dendrite penetration of the separator and short circuits, and improving battery cycle life.

[0013] Preferably, the adhesive comprises at least one of polyvinylidene fluoride, polyvinyl alcohol, sodium polyacrylate, sodium carboxymethyl cellulose, sodium alginate, styrene-butadiene rubber, and polytetrafluoroethylene.

[0014] Preferably, the additive includes at least one of the following: sodium dodecylbenzenesulfonate, sodium dodecyl sulfate, sodium stearate, hexadecyltrimethylammonium bromide, sorbitol, polyethylene glycol, sodium pyrophosphate, sodium silicate, polyacrylic acid, phytic acid, and graphene oxide.

[0015] The optimized proportion of mesoporous ZnHHTP conductive MOF in the coating fully leverages its high specific surface area and mesoporous channels, ensuring rapid electron and zinc ion transport. A lower proportion ensures a stable interface and efficient dendrite-resistant core protection, while an excessively high proportion results in insufficient coating adhesion and loss of effectiveness. Optimizing the binder proportion balances adhesion strength and ionic conductivity. An appropriate amount of binder absorbs stress during zinc deposition / stripping, preventing electrode pulverization; an excessively high proportion reduces ionic conductivity, thus affecting rate performance. The selected binder type combines excellent adhesion with electrolyte wetting conditions, making it suitable for aqueous electrolyte systems. Combined use further optimizes coating flexibility and electrolyte corrosion resistance. The introduction of additives provides functions such as stable interface pH, ion chelation, corrosion inhibition, and water retention without compromising the core functionality of the conductive MOF. The synergistic effects of the components, considering the high conductivity / ion transport characteristics of the modified material, reduce interfacial impedance, and minimize dendrite formation and side reactions, achieve high cycle stability and high rate performance in aqueous zinc batteries.

[0016] A second aspect of the present invention is to provide a method for preparing the above-mentioned mesoporous conductive MOF modified zinc anode, the steps of which include:

[0017] S1. A mixture of zinc nitrate aqueous solution and 2,3,6,7,10,11-hexahydroxytriphenyl was reacted. After the reaction was completed, the mixture was centrifuged, washed, and dried in sequence to obtain mesoporous ZnHHTP conductive MOF nanomaterials.

[0018] S2. Prepare a coating slurry by mixing the mesoporous ZnHHTP conductive MOF nanomaterial, binder, additives and solvent;

[0019] S3. The coating slurry is applied to both sides of the surface-cleaned zinc foil, dried, and rolled to obtain the mesoporous conductive MOF modified zinc anode.

[0020] Preferably, in step S1, the pH of the reaction is adjusted to 8-10 by adding ammonia water with a concentration of 0.5-1.0 mol / L, the reaction temperature is 60-90℃, and the reaction time is 4-8 h; the concentration of the zinc nitrate aqueous solution is 3-20 mmol / L; and the molar ratio of zinc nitrate to 2,3,6,7,10,11-hexahydroxytriphenyl is 1:(0.9-1.1).

[0021] Preferably, in step S2, the solvent includes at least one of water, anhydrous ethanol, isopropanol, N-methylpyrrolidone, and N,N-dimethylformamide; and the viscosity of the coating slurry is 3000-10000 mPa·s.

[0022] Preferably, in step S3, the coating method includes at least one of spraying, blade coating, and slot extrusion coating.

[0023] By optimizing the solution concentration, ammonia concentration, and pH of the mesoporous ZnHHTP conductive MOF nanomaterials, the particle size and pore size distribution of the mesoporous ZnHHTP conductive MOF can be controlled, ensuring rapid transport of zinc ions at the interface. Optimization of reaction temperature and time facilitates low-cost manufacturing, reducing the cost of zinc anode materials modified with mesoporous conductive MOF. The solvent selection for the slurry preparation ensures uniform dispersion and dissolution of the mesoporous conductive MOF nanomaterials, binders, and additives, meeting the environmental requirements of aqueous batteries, while also possessing suitable volatility for subsequent drying and film formation. Slurry viscosity control balances coating smoothness and film thickness uniformity, preventing excessively low viscosity from causing thin or uneven coatings, and preventing excessively high viscosity from clogging the pores of the mesoporous conductive MOF, ensuring unobstructed ion transport channels. Different coating methods can achieve precise coating on one or both sides, accurately control the coating thickness, improve production adaptability and efficiency, reduce industrial production costs, and ultimately help the zinc anode material modified by mesoporous conductive MOF to achieve core advantages such as resistance to dendrite growth and corrosion and hydrogen evolution, thereby improving the overall performance of aqueous zinc batteries.

[0024] A third aspect of the present invention is to provide the application of the above-mentioned mesoporous conductive MOF modified zinc anode in an aqueous zinc-based battery, the aqueous zinc-based battery comprising at least one of: zinc-nickel battery, zinc-manganese battery, zinc-vanadium battery, zinc-iodine battery, zinc-bromine battery, lithium zinc-manganese oxide battery, zinc-zinc battery, and zinc-copper battery.

[0025] The present invention adopts the above technical solution and has the following technical effects compared with the prior art:

[0026] (1) The zinc anode material of the present invention has the ability to be thin and light, highly wettable to aqueous electrolytes, promote ion desolvation, and accelerate ion transport. It inhibits dendrite growth from the root, and the channel structure binds water molecules to reduce activity. Combined with the corrosion inhibition function of additives, it greatly reduces the corrosion and hydrogen evolution of zinc anode, solves the core pain points of dendrite short circuit and corrosion failure of traditional zinc anode, and significantly extends the cycle life of battery.

[0027] (2) This invention modifies the mesoporous conductive MOF coating, which forms an efficient electron-ion transport network with high conductivity and mesoporous channels. Combined with the excellent electrolyte wettability of the interface, it constructs continuous ion channels, which synergistically reduces the internal resistance of the electrode and the charge transfer impedance, thus solving the problem of high interface impedance and significantly improving the rate performance and cycle stability of the battery.

[0028] (3) The preparation process of the zinc anode material of the present invention is simple and reliable, low in cost, suitable for industrial production, and has broad prospects for industrial application. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the composition of the zinc anode material modified by mesoporous conductive MOF according to the present invention.

[0030] Figure 2 The wetting angle of the zinc anode modified by the mesoporous conductive MOF of this invention to an aqueous electrolyte.

[0031] Figure 3 Cycling curves of zinc-zinc batteries assembled using the zinc anode modified by the mesoporous conductive MOF of this invention. Detailed Implementation

[0032] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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.

[0033] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0034] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but this is not intended to limit the scope of the invention.

[0035] Example 1

[0036] This invention provides a zinc anode modified with mesoporous conductive MOF and its preparation method, comprising: a zinc foil and a mesoporous conductive MOF coating on both sides of the zinc foil; the mesoporous conductive MOF is a mesoporous ZnHHTP conductive MOF nanomaterial, which exhibits regular hexagonal rod-shaped crystals with a lateral dimension of 250 nm, a radial length of about 2 μm, and an average pore size of 13 nm.

[0037] Preparation methods include:

[0038] (1) 600 mg Zn(NO3)2·6H2O was added to 450 mL of water and stirred thoroughly to prepare an aqueous solution of zinc nitrate; 50 mL of 0.8 M ammonia solution was added to adjust the pH of the reaction to 9; then 650 mg of 2,3,6,7,10,11-hexahydroxytriphenyl (HHTP) was added immediately; the reaction mixture was heated and stirred at 85 °C for 6 h; finally, after centrifugation, washing with water and ethanol several times, and drying, blue powdery mesoporous ZnHHTP conductive MOF nanomaterials were obtained.

[0039] (2) Weigh 0.531g of mesoporous HHTP nanoparticles, 0.031g of polyvinylidene fluoride (PVDF) binder and 0.063g of sodium stearate additive, add an appropriate amount of N-methylpyrrolidone (NMP) solvent, and continuously stir and disperse to achieve a uniform slurry. Control the amount of NMP added to adjust the viscosity of the slurry to 5000mPa·s to obtain mesoporous ZnHHTP conductive MOF coating slurry;

[0040] (3) Soak 20μm or 50μm zinc foil in anhydrous ethanol and sonicate for 10 min to clean the surface. After drying, apply mesoporous ZnHHTP conductive MOF coating slurry to both sides of the foil, control the wet film coating thickness on one side to be 10μm, and obtain mesoporous ZnHHTP conductive MOF modified zinc anode material after drying and rolling.

[0041] Mesoporous ZnHHTP conductive MOF nanoparticles are uniformly coated on the surface of zinc foil. Wetting angle tests on 2M ZnSO4 electrolyte show that... Figure 2 As shown, after modification with a mesoporous ZnHHTP conductive MOF coating, the wettability of the zinc anode material to the electrolyte was significantly improved, and the wetting angle decreased to 32°. The total thickness of the obtained zinc anode material was 25 μm or 55 μm (coating thickness 5 μm), and the coating areal density was 0.3 mg / cm³. 2 The mesoporous conductive MOF-modified zinc anode material prepared in Example 1 was immersed in 2M ZnSO4 for 12 hours, and the corrosion products were tested by X-ray diffraction. No obvious formation of basic zinc sulfate Zn4(OH)6SO4·xH2O corrosion products was found, indicating its good resistance to electrolyte corrosion.

[0042] Mesoporous conductive MOF-modified zinc anode material can accelerate the ion desolvation of electrolyte. Desolvation energy tests based on temperature-dependent electrochemical impedance spectroscopy fitting show that the ion desolvation energy of the (near) neutral Zn / / Zn symmetric battery assembled based on mesoporous conductive MOF-modified zinc anode material can reach 32.6 kJ / mol.

[0043] Example 2

[0044] This invention provides another mesoporous conductive MOF-modified zinc anode and its preparation method. The zinc anode material has a coating thickness of 10 μm and a coating areal density of 0.6 mg / cm³. 2 The thickness of the wet film coating on one side was 20 μm, and all other aspects were the same as in Example 1.

[0045] Example 3

[0046] This invention provides another mesoporous conductive MOF-modified zinc anode and its preparation method. The formulation of the mesoporous ZnHHTP conductive MOF coating slurry includes 0.438g of mesoporous HHTP nanoparticles, 0.125g of sodium carboxymethyl cellulose (CMC) binder, and 0.063g of phytic acid additive. An appropriate amount of deionized water is added as a solvent, and the mixture is continuously stirred and dispersed to achieve a uniform slurry. The viscosity of the slurry is controlled to 2500 mPa·s by adjusting the amount of deionized water added, thus obtaining the mesoporous ZnHHTP conductive MOF coating slurry. The rest of the process is the same as in Example 1.

[0047] Example 4

[0048] This invention provides another mesoporous conductive MOF-modified zinc anode and its preparation method. The obtained mesoporous ZnHHTP conductive MOF exhibits a lateral dimension of 200 nm, a radial length of approximately 2.5 μm, and an average pore size of 6 nm. In preparing the mesoporous ZnHHTP conductive MOF, the concentration of ammonia added was 1.5 M, and all other steps were the same as in Example 1.

[0049] Example 5

[0050] This invention provides another mesoporous conductive MOF-modified zinc anode and its preparation method. The formulation of the mesoporous ZnHHTP conductive MOF coating slurry is as follows: 0.375g mesoporous HHTP nanoparticles, 2.5g of 5% polyvinyl alcohol aqueous solution (Nafion) binder, and 0.125g of graphene oxide additive. An appropriate amount of deionized water is added as a solvent, and the mixture is continuously stirred and dispersed to achieve a uniform slurry. The viscosity of the slurry is controlled to 1800 mPa·s by adjusting the amount of deionized water added, thus obtaining the mesoporous ZnHHTP conductive MOF coating slurry. The mesoporous ZnHHTP conductive MOF coating slurry is then sprayed multiple times onto both sides of a cleaned zinc foil, controlling the coating loading on one side to be 0.8 mg / cm².2 The rest are the same as in Example 1.

[0051] Comparative Example 1

[0052] This comparative example provides a zinc anode material without surface coating modification treatment.

[0053] The zinc anode material had a wetting angle of 89° with the electrolyte. After immersion in 2M ZnSO4 for 12 hours, the zinc anode material of Comparative Example 1 underwent X-ray diffraction testing for corrosion products. A strong signal of basic zinc sulfate (Zn4(OH)6SO4·xH2O) corrosion products was observed, indicating severe corrosion in the 2M ZnSO4 electrolyte. The zinc anode material of Comparative Example 1 exhibited weak desolvation ability to electrolyte ions, with a desolvation energy of 42.8 kJ / mol.

[0054] Comparative Example 2

[0055] This comparative example provides another zinc anode material. The ZnHHTP conductive MOF in the coating does not have mesoporous characteristics. In the preparation process of the ZnHHTP conductive MOF, ammonia water is replaced with sodium acetate, and the rest is the same as in Example 1. The zinc anode material of Comparative Example 2 has a weaker ability to desolvate electrolyte ions, and its desolvation energy is 37.5 kJ / mol.

[0056] Comparative Example 3

[0057] This comparative example provides another zinc anode material, controlling the slurry viscosity to 12000 mPa·s, with a single-sided wet film coating thickness of 60 μm, and all other aspects being the same as in Example 1. The zinc anode material obtained using the scheme of Comparative Example 3 has a coating thickness of 80 μm and a coating areal density of 6.5 mg / cm³. 2 .

[0058] Application Examples

[0059] Aqueous zinc batteries were prepared using zinc anode materials from Examples 1-5 and Comparative Examples 1-3, respectively, and their performance was tested.

[0060] 1. Battery manufacturing

[0061] Zinc-zinc aqueous battery: Two 12mm diameter mesoporous conductive MOF modified zinc anode discs and a 16mm diameter GF / D glass fiber membrane are combined in a zinc-membrane-zinc sandwich structure, and 2M ZnSO4 electrolyte is added to obtain a zinc-zinc aqueous battery.

[0062] Zinc-manganese aqueous battery: A zinc negative electrode disc with a diameter of 12 mm modified by mesoporous conductive MOF, a GF / D glass fiber membrane with a diameter of 16 mm, and a manganese dioxide positive electrode disc with a diameter of 12 mm are combined in a zinc-membrane-manganese dioxide sandwich structure, and 2M ZnSO4 + 0.2M MnSO4 electrolyte is added to obtain a zinc-manganese aqueous battery.

[0063] Zinc-nickel aqueous battery: A zinc negative electrode disc with a diameter of 12 mm modified by mesoporous conductive MOF, a polypropylene microporous / non-woven composite separator with a diameter of 16 mm and a thickness of 120 μm, and a nickel hydroxide positive electrode disc with a diameter of 12 mm are combined in a zinc-film-nickel hydroxide sandwich structure, and an electrolyte of 7 M KOH + 0.5 M ZnO is added to obtain a zinc-nickel aqueous battery.

[0064] Zinc-iodine aqueous battery: A zinc negative electrode disc with a diameter of 12 mm modified by mesoporous conductive MOF, a GF / D separator with a diameter of 16 mm, and an iodine positive electrode disc with a diameter of 12 mm are combined in a zinc-film-iodine sandwich structure, and 2 M ZnSO4 electrolyte is added to obtain a zinc-iodine aqueous battery.

[0065] 2. Performance Test Results

[0066] 2.1 Example 1

[0067] The zinc-zinc electrohydraulic battery assembled in Example 1 achieved an excellent cycle life of 5 mA / cm². 2 The lower polarization potential is 78 mV, 5 mA / cm 2 Current density 1mAh / cm 2 Stable cycling for over 2500 hours can be achieved under deposition and stripping conditions; at 5 mA / cm 2 Stable cycling for over 600 hours can be achieved at a high depth of discharge of 60%.

[0068] The zinc-manganese aqueous battery assembled in Example 1 had discharge capacities of 318, 305, 292, 255, and 185 mAh / g at current densities of 0.02, 0.1, 0.5, 1.0, and 3.0 A / g, respectively, and could be stably cycled for more than 5000 times at 3.0 A / g.

[0069] The zinc-nickel aqueous battery assembled in Example 1 has a discharge capacity of up to 263 mAh / g at a current density of 0.05 A / g, and can still maintain a discharge capacity of 210 mAh / g when the current density is increased to 2.8 A / g; after 1000 cycles at 1.4 A / g, the capacity retention rate is 94.8%, showing excellent advantages of high capacity, high rate and long cycle life.

[0070] 2.2 Example 2

[0071] The zinc-zinc electrohydraulic battery obtained using the zinc anode material obtained in Example 2 achieves a speed of 5 mA / cm². 2 Current density 1mAh / cm 2 Stable cycling for over 2500 h can be achieved under deposition and stripping conditions; the zinc-manganese aqueous battery has discharge capacities of 325 mAh / g and 180 mAh / g at current densities of 0.02 and 3.0 A / g, respectively, and can be stably cycled for over 2500 times at 3.0 A / g; the obtained zinc-nickel battery can still maintain a discharge capacity of over 200 mAh / g at 2.8 A / g; and the capacity retention rate is over 92% after 1000 cycles at 1.4 A / g.

[0072] 2.3 Example 3

[0073] After modification with a mesoporous ZnHHTP conductive MOF coating, the zinc anode material of Example 3 exhibits a wetting angle of 15° with the electrolyte. The zinc-zinc electro-aqueous battery obtained using the zinc anode material of Example 3 achieves a current of 5 mA / cm². 2 The lower polarization potential is 88mV, 5mA / cm 2 Current density 1mAh / cm 2 Stable cycling for over 2800 hours can be achieved under deposition and stripping conditions; the zinc-manganese aqueous battery has discharge capacities of 315 mAh / g and 178 mAh / g at current densities of 0.02 and 3.0 A / g, respectively, and can be stably cycled for over 3000 times at 3.0 A / g; the obtained zinc-nickel battery can still maintain a discharge capacity of over 195 mAh / g at 2.8 A / g; and the capacity retention rate is over 90% after 1000 cycles at 1.4 A / g.

[0074] 2.4 Example 4

[0075] The zinc-zinc electrohydraulic battery obtained using the zinc anode material of Example 4 achieves a voltage of 5 mA / cm². 2 The lower polarization potential is 78 mV, 5 mA / cm 2 Current density 1mAh / cm 2 Stable cycling for over 3500 hours can be achieved under deposition and stripping conditions; the zinc-manganese aqueous battery has discharge capacities of 321 mAh / g and 195 mAh / g at current densities of 0.02 and 3.0 A / g, respectively, and can be stably cycled for over 3500 times at 3.0 A / g; the obtained zinc-nickel battery can still maintain a discharge capacity of over 206 mAh / g at 2.8 A / g; and the capacity retention rate is over 93.5% after 1000 cycles at 1.4 A / g.

[0076] 2.5 Example 5

[0077] The mesoporous conductive MOF coating on the zinc anode inhibits the shuttle of iodine to the zinc metal surface, and the prepared zinc-iodine aqueous battery has a coulombic efficiency of over 99% and a cycle life of over 5000 cycles.

[0078] 2.6 Comparative Example 1

[0079] The zinc-zinc electrohydraulic battery obtained using the zinc anode material of Comparative Example 1 operates at 5 mA / cm². 2 The lower polarization potential is 120mV, 5mA / cm 2 Current density 1mAh / cm 2 A short circuit occurred after 80 hours of cycling under deposition and stripping conditions; the zinc-manganese aqueous battery had discharge capacities of 310 mAh / g and 150 mAh / g at current densities of 0.02 and 3.0 A / g, respectively, and a short circuit occurred after 300 stable cycles at 3.0 A / g; the obtained zinc-nickel battery had a discharge capacity of 240 mAh / g at a current density of 0.05 A / g, and maintained a discharge capacity of 160 mAh / g when the current density was increased to 2.8 A / g; a short circuit occurred after 120 cycles at 1.4 A / g.

[0080] 2.7 Comparative Example 2

[0081] The zinc-zinc electrohydraulic battery obtained using the zinc anode material of Comparative Example 2 achieved a voltage of 5 mA / cm². 2 The lower polarization potential is 100mV, at 5mA / cm 2 Current density 1mAh / cm 2 A short circuit occurred after 420 hours of cycling under deposition-stripping conditions. The zinc-manganese aqueous battery exhibited discharge capacities of 305 mAh / g and 110 mAh / g at current densities of 0.02 and 3.0 A / g, respectively, and short-circuited after 700 cycles at 3.0 A / g. The obtained zinc-nickel battery showed a discharge capacity of 235 mAh / g at a current density of 0.05 A / g, maintaining a discharge capacity of 170 mAh / g when the current density was increased to 2.8 A / g; however, a short circuit occurred after 650 cycles at 1.4 A / g. Therefore, aqueous batteries assembled with zinc anode materials possessing conductive MOF coatings lacking mesoporous characteristics exhibit low specific capacity, poor fast-charge / discharge capability, and poor cycle performance.

[0082] 2.8 Comparative Example 3

[0083] The zinc-zinc electrohydraulic battery obtained using the zinc anode material of Comparative Example 3 achieved a speed of 5 mA / cm². 2 The lower polarization potential is 110mV, indicating that excessive coating thickness is detrimental to ion transport and may even increase polarization when using the same amount of electrolyte. The zinc-zinc electro-aqueous battery operates at 5mA / cm². 2 Current density 1mAh / cm 2A short circuit occurred after 920 hours of cycling under deposition-stripping conditions. The zinc-manganese aqueous battery exhibited discharge capacities of 295 mAh / g and 85 mAh / g at current densities of 0.02 A / g and 3.0 A / g, respectively, and short-circuited after 580 cycles at 3.0 A / g. The obtained zinc-nickel battery showed a discharge capacity of 242 mAh / g at a current density of 0.05 A / g, maintaining a discharge capacity of 175 mAh / g when the current density was increased to 2.8 A / g; after 500 cycles at 1.4 A / g, the capacity retention rate was 85.5%. Therefore, aqueous batteries assembled from zinc anode materials obtained with excessively thick conductive MOF coatings exhibit low specific capacity, poor fast-charge / discharge capability, and poor cycle performance.

[0084] 3. Conclusion

[0085] The mesoporous conductive MOF of this invention possesses a large specific surface area and mesoporous channel structure, which can accelerate zinc ion desolvation. The mesoporous ZnHHTP conductive MOF, with its designed mesoporous channels and particle size, serves as a surface coating for the zinc anode, facilitating the construction of efficient ion transport channels, accelerating zinc ion diffusion and migration, achieving a uniform ion concentration on the zinc anode surface, and guiding uniform deposition to suppress dendrite formation. Furthermore, the large specific surface area and mesoporous channel structure of the mesoporous conductive MOF bind water molecules within the channels, reducing water activity, weakening hydrogen evolution corrosion of the zinc anode, and ensuring the lifespan of the aqueous zinc battery.

[0086] Mesoporous conductive MOFs exhibit excellent conductivity, reducing electrode internal resistance, promoting rapid electron transport, and minimizing polarization. The coating's excellent wettability (wetting angle less than 60°) allows for uniform electrolyte coverage and penetration into the pores, forming continuous ion channels and reducing Zn content. 2+ Migration resistance and charge transfer impedance. This synergistically balances high conductivity and ion transport efficiency, effectively improving the battery's fast charge / discharge rate performance.

[0087] Multi-component synergy and process adaptation ensure comprehensive performance. 60-90% of the MOF in the coating plays a core role, 5-30% of the binder balances the bonding strength and flexibility, and additives assist in corrosion inhibition and interface stabilization. The synergistic effect of each component reduces side reactions. The preparation process adopts solution synthesis and simple coating, which can precisely control the coating thickness of 0.1-10μm and the lightweight characteristics, making it suitable for industrial production and helping batteries achieve the comprehensive requirements of high energy density and long cycle life.

[0088] In summary, the mesoporous conductive MOF-modified zinc anode material of this invention addresses the core pain points of traditional zinc anodes, such as easy dendrite growth, severe corrosion, and high interfacial impedance, as well as the difficulty of existing modified materials in balancing conductivity / ion transport efficiency and complex preparation processes. It achieves a breakthrough in aqueous zinc battery anodes with high cycle stability and high rate performance. Compared with existing modified zinc anodes, this invention uses a mesoporous ZnHHTP conductive MOF with high specific surface area, precisely controlled mesoporous structure, and excellent conductivity. It requires less material and has controllable cost. The resulting modified anode possesses rapid ion desolvation capability, continuous ion transport channels, and a stable electrode interface, significantly inhibiting dendrite growth and hydrogen evolution due to corrosion, and reducing interfacial impedance. This modified anode can endow aqueous zinc batteries with higher energy density, superior fast charge / discharge capability, and longer service life, and its preparation process is simple and suitable for industrial production.

[0089] The above description is merely a preferred embodiment of the present invention and does not limit the implementation and protection scope of the present invention. Those skilled in the art should realize that any equivalent substitutions and obvious changes made based on the description and illustrations of the present invention should be included within the protection scope of the present invention.

Claims

1. A mesoporous conductive MOF-modified zinc anode, characterized in that, include: A zinc foil and a mesoporous conductive MOF coating applied to both sides of the zinc foil; The mesoporous conductive MOF coating, by weight, comprises: 50-90 parts of mesoporous ZnHHTP conductive MOF nanomaterials, 5-30 parts of binder, and 0-20 parts of additives; the mesoporous ZnHHTP conductive MOF nanomaterials have mesoporous channels with a pore size of 2-20 nm and a pore volume of 0.3-0.8 cm³. 3 / g, conductivity greater than 0.05S / m.

2. The mesoporous conductive MOF-modified zinc anode according to claim 1, characterized in that, The thickness of each mesoporous conductive MOF coating layer is independently 0.1-30 μm, and the areal density is independently 0.2-3 mg / cm³. 2 .

3. The mesoporous conductive MOF-modified zinc anode according to claim 1, characterized in that, The mesoporous conductive MOF coating has a wetting angle of less than 60° to water.

4. The mesoporous conductive MOF-modified zinc anode according to claim 1, characterized in that, The adhesive includes at least one of the following: polyvinylidene fluoride, polyvinyl alcohol, sodium polyacrylate, sodium carboxymethyl cellulose, sodium alginate, styrene-butadiene rubber, and polytetrafluoroethylene.

5. The mesoporous conductive MOF-modified zinc anode according to claim 1, characterized in that, The additives include at least one of the following: sodium dodecylbenzenesulfonate, sodium dodecyl sulfate, sodium stearate, hexadecyltrimethylammonium bromide, sorbitol, polyethylene glycol, sodium pyrophosphate, sodium silicate, polyacrylic acid, phytic acid, and graphene oxide.

6. A method for preparing a mesoporous conductive MOF-modified zinc anode as described in any one of claims 1-5, characterized in that, step include: S1. A mixture of zinc nitrate aqueous solution and 2,3,6,7,10,11-hexahydroxytriphenyl was reacted. After the reaction was completed, the mixture was centrifuged, washed, and dried in sequence to obtain mesoporous ZnHHTP conductive MOF nanomaterials. S2. Prepare a coating slurry by mixing the mesoporous ZnHHTP conductive MOF nanomaterial, binder, additives and solvent; S3. The coating slurry is applied to both sides of the surface-cleaned zinc foil, dried, and rolled to obtain the mesoporous conductive MOF modified zinc anode.

7. The preparation method according to claim 6, characterized in that, In step S1, the pH of the reaction is adjusted to 8-10 by adding ammonia water with a concentration of 0.5-1.0 mol / L, the reaction temperature is 60-90℃, and the reaction time is 4-8 h; the concentration of the zinc nitrate aqueous solution is 3-20 mmol / L; the molar ratio of zinc nitrate to 2,3,6,7,10,11-hexahydroxytriphenyl is 1:(0.9-1.1).

8. The preparation method according to claim 6, characterized in that, In step S2, the solvent includes at least one of water, anhydrous ethanol, isopropanol, N-methylpyrrolidone, and N,N-dimethylformamide; the viscosity of the coating slurry is 3000-10000 mPa·s.

9. The preparation method according to claim 6, characterized in that, In step S3, the coating method includes at least one of spraying, blade coating, and slot extrusion coating.

10. The application of a mesoporous conductive MOF-modified zinc anode as described in any one of claims 1-5, or a mesoporous conductive MOF-modified zinc anode prepared by the preparation method as described in any one of claims 6-9, in an aqueous zinc-based battery, characterized in that, The aqueous zinc-based battery includes at least one of the following: zinc-nickel battery, zinc-manganese battery, zinc-vanadium battery, zinc-iodine battery, zinc-bromine battery, lithium zinc-manganese oxide battery, zinc-zinc battery, and zinc-copper battery.

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