Zinc metal anode materials modified with ion / electron dual-conductor interface films, their preparation and applications

Abstract

This invention relates to a zinc metal anode material modified with an ion / electron dual-conductor interface film, its preparation, and its application, belonging to the field of zinc-ion battery technology. The zinc metal anode material modified with an ion / electron dual-conductor interface film is a zinc-containing metal material with an ion / electron dual-conductor interface film on its surface; wherein, the ion / electron dual-conductor interface film is a polymer film doped with conductive materials and Zn(CF3SO3)2, with an ionic conductivity of 0.1–0.8 S / m and an electronic conductivity of 0.01–0.1 S / m. This anode material possesses synergistic ion and electron transport capabilities, endowing the interface film with abundant nucleation sites, which can guide zinc ion nucleation, facilitating zinc deposition, inhibiting zinc dendrite growth, and reducing electrode polarization. When applied to aqueous zinc-ion batteries, it exhibits excellent electrochemical performance. Moreover, the preparation process of this anode material is simple, environmentally friendly, and easy to promote, showing great application prospects in the field of aqueous zinc-ion batteries.

Description

Technical Field

[0001] This invention relates to a zinc metal anode material modified with an ion / electron dual-conductor interface film, its preparation and application, belonging to the field of zinc-ion battery technology. Background Technology

[0002] With the continuous development of society, electrochemical energy storage systems that are safe, stable, low-cost, and environmentally friendly are attracting increasing attention. Zinc, as an inexpensive and abundant metal, has a high volumetric capacity (5855 mAh cm⁻¹). -3 Zinc-ion batteries possess advantages such as high oxidation-reduction potential (-0.76V relative to a standard hydrogen electrode) and low redox potential. Based on the inherent advantages of the zinc metal anode, aqueous zinc-ion batteries are a popular candidate for next-generation energy storage devices. In recent years, various aqueous zinc-based batteries, such as Zn-MnO2, Zn-V2O5, and Zn-LiMn2O4 systems, have been extensively studied and significant progress has been made. However, due to the tendency of uneven nucleation of the zinc anode to result in dendritic growth and severe hydrogen corrosion driven by thermodynamics, these problems lead to the formation of unstable interfaces in the zinc metal during cycling, severely hindering the large-scale application of aqueous zinc-ion batteries.

[0003] Effective artificial interfacial films can prevent direct contact between the electrolyte and zinc metal, regulate zinc nucleation and hydrogen release (HER), thereby achieving long-life zinc metal anodes. Therefore, researchers have designed various artificially modified films on the surface of metal anodes. Based on material type, they can be mainly divided into electronically conductive (EC) and ionically conductive (IC) interfacial films. The high electronic conductivity of EC films allows for rapid distribution of local current on the electrode surface, suppressing dendrite formation. However, the unbalanced electronic / ionic conductivity leads to zinc deposition on top of the EC film, causing the interfacial film's protective function to fail. IC films make zinc metal the sole electronic conductor in the electrode, ensuring that zinc deposition begins on the metal surface. Simultaneously, they allow zinc ions to transport within the film, preferentially regulating zinc nucleation sites. However, zinc deposition / deposition is accompanied by changes in the anode volume. This phenomenon causes poor contact between the IC interfacial film and the zinc metal interface, leading to broken electron transport in the composite electrode, poor rate performance, and ultimately battery failure. Therefore, exploring the design and synthesis of novel artificial interface films, balancing ion / electron transport rates, and clarifying the internal mechanisms of action are of great guiding significance and universal applicability for subsequent zinc anode interface modification and the construction of high-rate aqueous zinc-ion batteries. Summary of the Invention

[0004] To address the shortcomings of current interface films, this invention provides a zinc metal anode material modified with an ion / electron dual-conductor interface film, its preparation, and its application. The interface film utilizes a polymer film of doped conductive materials and Zn(CF3SO3)2, which possesses synergistic ion and electron transport capabilities, endowing the interface film with abundant nucleation sites. This guides zinc ion nucleation, facilitating zinc deposition, inhibiting zinc dendrite growth, and reducing electrode polarization. When applied to aqueous zinc-ion batteries, this ion / electron dual-conductor interface film-modified zinc metal anode material improves the battery's electrochemical performance. Furthermore, the preparation process of this ion / electron dual-conductor interface film-modified zinc metal anode material is simple, environmentally friendly, and easy to promote.

[0005] The objective of this invention is achieved through the following technical solutions.

[0006] Zinc metal anode materials modified with ion / electron dual conductor interface films are zinc-containing metal materials with ion / electron dual conductor interface films on their surfaces.

[0007] The ion / electron dual-conductor interface film is a polymer film doped with conductive material and Zn(CF3SO3)2, with an ionic conductivity of 0.1 to 0.8 S / m and an electronic conductivity of 0.01 to 0.1 S / m.

[0008] Preferably, the conductive material is MXene (preferably Ti3C2T). x The conductive material, Zn(CF3SO3)2, and polymer are preferably selected from one or more of the following: Ti3AlC2, reduced graphene oxide, or heteroatom-doped graphene. The polymer is polyvinyl alcohol, polyethylene glycol, polyethylene oxide, and poly(vinylidene fluoride-co-hexafluoropropylene). Correspondingly, the mass ratio of the conductive material, Zn(CF3SO3)2, and polymer is more preferably 1:(1-3):(3-8).

[0009] Preferably, the zinc-containing metal material is zinc foil or zinc alloy foil.

[0010] Preferably, the thickness of the ion / electron dual conductor interface film is 200 nm to 40 μm.

[0011] The preparation method of zinc metal anode material based on ion / electron dual conductor interface film modification includes the following steps:

[0012] (1) Mix the conductive material, Zn(CF3SO3)2, polymer and water, and heat and stir until a viscous slurry is formed;

[0013] (2) After coating the slurry prepared in step (1) onto the surface of the zinc-containing metal material, freeze it first, then thaw it, and repeat the freeze-thaw operation 3 to 5 times to obtain the zinc metal anode material modified based on the ion / electron dual conductor interface film.

[0014] Preferably, in step (1), the concentration of the conductive material in the slurry is 1 to 5 mg / mL.

[0015] Preferably, in step (1), the mixture is stirred at 60–90°C until it becomes a viscous slurry.

[0016] Preferably, in step (2), the freezing temperature for each freezing is -40 to -20°C and the freezing time is 30 min to 24 h, and the thawing temperature for each thawing is 20 to 40°C and the thawing time is 2 to 24 h.

[0017] Zinc metal anode materials modified with ion / electron dual-conductor interface films are used as anodes in aqueous zinc-ion batteries.

[0018] Beneficial effects:

[0019] (1) The ion / electron dual-conductor interface film of the present invention has high ionic conductivity and electronic conductivity, which enables the local current on the electrode surface to be distributed rapidly, suppresses the formation of dendrites, and ensures that zinc deposition starts from the metal surface. It allows zinc ions to be transported inside the film, preferentially regulates the nucleation sites of zinc, avoids the phenomenon of zinc deposition on the film caused by the unbalanced electronic / ionic conductivity of a single electronic conductive film, and avoids the problem of poor electrode rate performance caused by single ionic conductivity, which leads to battery failure.

[0020] (2) In the ion / electron dual-conductor interface film of the present invention, the conductive material can form valence bonds with the hydrogen bonds in the polymer, which improves the solubility of the material and promotes the electronic conductivity of the interface film; the addition of zinc salt provides a transport path for zinc ions, providing a channel for ion transport. In addition, the conductive material and the polymer form a layered porous structure, which allows the zinc salt to be uniformly and stably dispersed throughout the film, and the addition of zinc salt strengthens the bonding strength between the conductive material and the polymer. The two work together to promote the high-speed ion / electron dual-conductor channel.

[0021] (3) The present invention introduces a higher amount of conductive material as an additive to the interface film, which effectively improves the electronic conductivity of the interface film; in addition, the preferred zinc salt concentration activates the ion transport pathway of the interface film and promotes the interfacial transport rate of zinc ions.

[0022] (4) In the preparation process of the ion / electron dual conductor interface film of the present invention, multiple freeze-thaw cycles are performed. The main purpose is to utilize the formed ice crystals to form a porous structure in the interface film, and the abundant pores can effectively improve the ion / electron transport rate.

[0023] (5) The zinc metal anode material modified by the ion / electron dual conductor interface film described in this invention is used as an anode material in aqueous zinc-ion batteries. It has excellent electrochemical performance. Moreover, the preparation process of this anode material is simple, green and environmentally friendly, and easy to promote. It has a good application prospect in the field of aqueous zinc-ion batteries. Attached Figure Description

[0024] Figure 1 The image shows a surface electron microscope (SEM) image of the negative electrode material 10 prepared in Example 1.

[0025] Figure 2 This is a cross-sectional electron microscope image of the negative electrode material 10 prepared in Example 1.

[0026] Figure 3 The battery assembled in Example 1 operates at a current density of 20 mA / cm². 2 The capacity is 1mAh / cm 2 Cyclic performance graph.

[0027] Figure 4 The battery assembled in Example 1 operates at a current density of 20 mA / cm². 2 The capacity is 1mAh / cm 2 Scanning electron microscope image of the negative electrode surface after 100 cycles.

[0028] Figure 5 This is a comparison chart of the battery assembled in Example 1 and the battery assembled in Comparative Example 1 under long-cycle performance testing at 0.5C rate.

[0029] Figure 6 This is a scanning electron microscope image of the surface of the negative electrode of the full cell assembled in Example 1 after 100 cycles.

[0030] Figure 7 The battery assembled in Comparative Example 1 operates at a current density of 20 mA / cm². 2 The capacity is 1mAh / cm 2 Cyclic performance graph.

[0031] Figure 8 The battery assembled in Comparative Example 1 operates at a current density of 20 mA / cm². 2 The capacity is 1mAh / cm 2 Scanning electron microscope image of the negative electrode surface after 100 cycles.

[0032] Figure 9 This is a scanning electron microscope image of the surface of the negative electrode of the full cell assembled in Comparative Example 1 after 100 cycles. Detailed Implementation

[0033] The present invention will be further described below with reference to specific embodiments. Unless otherwise specified, the methods described are conventional methods, and the raw materials described are obtainable from publicly available commercial sources.

[0034] In the following embodiments and comparative examples:

[0035] SEM characterization: The microstructure of the samples was observed using a field emission scanning electron microscope (Hitachi SU-7) with an accelerating voltage of 5.0 kV;

[0036] Ionic conductivity testing: Assemble a stainless steel interface film and a stainless steel blocking electrode, and perform AC impedance testing within a frequency range of 10 to 10⁻⁶. 5 Hz, AC amplitude 5mV; the ionic conductivity of the interface film is calculated by measuring the interface film thickness, resistance value and stainless steel electrode contact area.

[0037] Electronic conductivity test: Assemble a stainless steel | interface film | stainless steel blocking electrode, apply a 1V polarization voltage to the test electrode, and record the current change curve over time; only electrons can continuously pass through the electrode, record the steady-state current, polarization voltage, interface film thickness and area, and calculate the electronic conductivity.

[0038] Assembly of CR 2032 batteries: Using the negative electrode material prepared in the examples or comparative examples as the positive and negative electrodes, glass fiber as the separator, 2M zinc trifluoromethanesulfonate Zn(CF3SO3)2 as the solute and deionized water as the solvent of the electrolyte, a pair of batteries are assembled; using the negative electrode material prepared in the examples or comparative examples as the negative electrode, LiMn2O4 as the positive electrode, 1M Zn(CF3SO3)2 and 2M lithium sulfate Li2SO4 as the solutes of the electrolyte, and deionized water as the solvent of the electrolyte, a full battery is assembled.

[0039] Electrochemical performance testing: The CR 2032 battery was tested using the Land system, and the test data was recorded using software.

[0040] Example 1

[0041] (1) 10 mg Ti3C2T x Add 20 mg Zn(CF3SO3)2 to 10 mL of deionized water, stir and mix well, then add 50 mg polyvinyl alcohol, and then heat to 80 °C and stir to form a viscous slurry;

[0042] (2) After scraping the slurry onto the zinc foil surface with a scraper, freeze it at -20°C for 6 hours, then thaw it at 30°C for 12 hours. Repeat the freezing-thawing operation three times to obtain the zinc metal anode material modified with the ion / electron dual conductor interface film, which is referred to as anode material 10.

[0043] The microstructure of the negative electrode material 10 prepared in this embodiment was characterized. Figure 1 The surface SEM image shows that the interface film on the surface of the composite material is completely covered without obvious wrinkles; Figure 2 The cross-sectional SEM image shows that the interface film tightly covers the zinc foil surface, and the thickness of the interface film is about 15 μm.

[0044] According to tests and calculations, the ionic conductivity of the interfacial film in the negative electrode material 10 is 0.4 S / m, and the electronic conductivity is 0.04 S / m.

[0045] The negative electrode material 10 prepared in this embodiment was used as the positive and negative electrodes to assemble a CR 2032 battery, and its cycle performance was tested. Figure 3 The test results show that at a current density of 20 mA / cm², 2 and a capacity of 1mAh / cm 2 Under these conditions, the voltage curve of the negative electrode remains flat after more than 1000 hours, with an overpotential of only 33mV, which is small and has no obvious fluctuations.

[0046] The negative electrode material 10 prepared in this embodiment was used as the positive and negative electrodes to assemble a CR 2032 battery, and the current density was 20 mA / cm². 2 and a capacity of 1mAh / cm 2 Under the condition of 100 cycles, the battery was disassembled and the microstructure of the negative electrode after 100 cycles was observed. It was found that its surface was clear and smooth, without obvious dendrite growth, such as Figure 4 As shown.

[0047] Using the negative electrode material 10 prepared in this embodiment as the negative electrode and LiMn2O4 as the positive electrode, a CR2032 full cell was assembled, and its long-term cycling performance was tested at a rate of 0.5C (1C = 148 mAh / g). Figure 5 The test results show that the full battery assembled with negative electrode material 10 exhibits excellent cycle stability, and the capacity can still be maintained at 64mAh / g after 440 cycles.

[0048] Using the negative electrode material 10 prepared in this embodiment as the negative electrode and LiMn2O4 as the positive electrode, a CR2032 full cell was assembled. It was cycled for 100 cycles at 0.5C. Afterward, the full cell was disassembled, and the microstructure of the negative electrode after 100 cycles was observed. It was found that its surface was smooth and zinc was uniformly deposited. Figure 6 As shown.

[0049] Example 2

[0050] Based on Example 1, only the polyvinyl alcohol in step (1) of Example 1 is replaced with polyethylene oxide. All other conditions and steps are the same as in Example 1. Accordingly, a zinc metal anode material modified with an ion / electron dual conductor interface film is obtained, which is referred to as anode material 20.

[0051] The anode material 20 prepared in this embodiment was characterized by microstructure. According to the characterization results, the zinc foil is coated with an interface film with a thickness of about 15 μm and the surface is flat and orderly.

[0052] According to tests and calculations, the ionic conductivity of the interfacial film in the negative electrode material 20 is 0.3 S / m, and the electronic conductivity is 0.04 S / m.

[0053] The negative electrode material 20 prepared in this embodiment was used as the positive and negative electrodes to assemble a CR 2032 battery, and cycle performance tests were conducted. According to the test results, at a current density of 20 mA / cm², the battery performed well. 2 and a capacity of 1mAh / cm 2 Under these conditions, the voltage curve of the negative electrode remains flat after more than 800 hours, with an overpotential of only 35mV, which is small and has no obvious fluctuations.

[0054] The negative electrode material 20 prepared in this embodiment was used as the positive and negative electrodes to assemble a CR 2032 battery, and the battery was tested at a current density of 20 mA / cm². 2 and a capacity of 1mAh / cm 2 Under the condition of 100 cycles, the battery was disassembled and the microstructure of the negative electrode after 100 cycles was observed. It was found that its surface was clear and flat, with no obvious dendrite growth.

[0055] Using the negative electrode material 20 prepared in this embodiment as the negative electrode and LiMn2O4 as the positive electrode, a CR2032 full cell was assembled, and its long-term cycling performance was tested at a rate of 0.5C. The test results show that the full cell assembled using negative electrode material 20 exhibits excellent cycling stability, maintaining a capacity of 69 mAh / g after 400 cycles.

[0056] Using the negative electrode material 20 prepared in this embodiment as the negative electrode and LiMn2O4 as the positive electrode, a CR2032 full cell was assembled and cycled for 100 cycles at a rate of 0.5C. After that, the full cell was disassembled and the microstructure of the negative electrode after 100 cycles was observed. It was found that its surface was smooth and zinc was uniformly deposited.

[0057] Example 3

[0058] Based on Example 1, only the Ti3C2T in step (1) of Example 1 is changed. xThe mass was adjusted to 20 mg, and other conditions and steps were the same as in Example 1. Accordingly, zinc metal anode material modified with ion / electron dual conductor interface film was obtained, which is referred to as anode material 11.

[0059] The negative electrode material 11 prepared in this embodiment was characterized by microstructure. According to the characterization results, the surface of the zinc foil is covered with an interface film with a thickness of about 15 μm, and the surface is flat and orderly.

[0060] According to tests and calculations, the ionic conductivity of the interfacial film in the negative electrode material 11 is 0.5 S / m, and the electronic conductivity is 0.08 S / m.

[0061] The negative electrode material 11 prepared in this embodiment was used as the positive and negative electrodes to assemble a CR 2032 battery, and cycle performance tests were conducted. The test results show that at a current density of 20 mA / cm², the battery performs well. 2 and a capacity of 1mAh / cm 2 Under these conditions, the voltage curve of the negative electrode remains flat after more than 1000 hours, with an overpotential of only 40mV, which is small and has no obvious fluctuations.

[0062] The negative electrode material 11 prepared in this embodiment was used as the positive and negative electrodes to assemble a CR 2032 battery pair, with a current density of 20 mA / cm². 2 and a capacity of 1mAh / cm 2 Under the condition of 100 cycles, the battery was disassembled and the microstructure of the negative electrode after 100 cycles was observed. It was found that its surface was clear and flat, with no obvious dendrite growth.

[0063] Using the negative electrode material 11 prepared in this embodiment as the negative electrode and LiMn2O4 as the positive electrode, a CR2032 full cell was assembled, and its long-term cycling performance was tested at a rate of 0.5C. The test results show that the full cell assembled using negative electrode material 11 exhibits excellent cycling stability, maintaining a capacity of 59 mAh / g after 400 cycles.

[0064] Using the negative electrode material 11 prepared in this embodiment as the negative electrode and LiMn2O4 as the positive electrode, a CR2032 full cell was assembled and cycled for 100 cycles at a rate of 0.5C. After that, the full cell was disassembled and the microstructure of the negative electrode after 100 cycles was observed. It was found that its surface was smooth and zinc was uniformly deposited.

[0065] Example 4

[0066] Based on Example 1, only the mass of Zn(CF3SO3)2 in step (1) of Example 1 was adjusted to 30mg, and the other conditions and steps were the same as in Example 1. Accordingly, a zinc metal anode material modified with an ion / electron dual conductor interface film was obtained, which is referred to as anode material 12.

[0067] The microstructure of the negative electrode material 12 prepared in this embodiment was characterized. According to the characterization results, the surface of the zinc foil is covered with an interface film with a thickness of about 15 μm, and the surface is flat and orderly.

[0068] According to tests and calculations, the ionic conductivity of the interfacial film in the negative electrode material 12 is 0.6 S / m, and the electronic conductivity is 0.05 S / m.

[0069] The negative electrode material 12 prepared in this embodiment was used as the positive and negative electrodes to assemble a CR 2032 battery, and cycle performance tests were conducted. The test results show that at a current density of 20 mA / cm², the battery performs well. 2 and a capacity of 1mAh / cm 2 Under these conditions, the voltage curve of the negative electrode remains flat after more than 1000 hours, with an overpotential of only 50mV, and the overpotential is small with no obvious fluctuations.

[0070] The negative electrode material 12 prepared in this embodiment was used as the positive and negative electrodes to assemble a CR 2032 battery, and the current density was 20 mA / cm². 2 and a capacity of 1mAh / cm 2 Under the condition of 100 cycles, the battery was disassembled and the microstructure of the negative electrode after 100 cycles was observed. It was found that its surface was clear and flat, with no obvious dendrite growth.

[0071] Using the negative electrode material 12 prepared in this embodiment as the negative electrode and LiMn2O4 as the positive electrode, a CR2032 full cell was assembled, and its long-term cycling performance was tested at a rate of 0.5C. The test results show that the full cell assembled using negative electrode material 12 exhibits excellent cycling stability, maintaining a capacity of 62 mAh / g after 400 cycles.

[0072] Using the negative electrode material 12 prepared in this embodiment as the negative electrode and LiMn2O4 as the positive electrode, a CR2032 full cell was assembled and cycled for 100 cycles at a rate of 0.5C. After that, the full cell was disassembled and the microstructure of the negative electrode after 100 cycles was observed. It was found that its surface was smooth and zinc was uniformly deposited.

[0073] Example 5

[0074] Based on Example 1, only the mass of polyvinyl alcohol in step (1) of Example 1 was adjusted to 80 mg, and the other conditions and steps were the same as in Example 1. Accordingly, zinc metal anode material modified with ion / electron dual conductor interface film was obtained, which is referred to as anode material 13.

[0075] The negative electrode material 13 prepared in this embodiment was characterized by microstructure. According to the characterization results, the surface of the zinc foil is covered with an interface film with a thickness of about 30 μm, and the surface is flat and orderly.

[0076] According to tests and calculations, the ionic conductivity of the interfacial film in the negative electrode material 13 is 0.2 S / m, and the electronic conductivity is 0.02 S / m.

[0077] The negative electrode material 13 prepared in this embodiment was used as the positive and negative electrodes to assemble a CR 2032 battery, and its cycle performance was tested. The test results show that at a current density of 20 mA / cm², the battery performs well. 2 and a capacity of 1mAh / cm 2 Under these conditions, the voltage curve of the negative electrode remains flat after more than 1000 hours, with an overpotential of only 50mV, and the overpotential is small with no obvious fluctuations.

[0078] The negative electrode material 13 prepared in this embodiment was used as the positive and negative electrodes to assemble a CR 2032 battery pair, with a current density of 20 mA / cm². 2 and a capacity of 1mAh / cm 2 Under the condition of 100 cycles, the battery was disassembled and the microstructure of the negative electrode after 100 cycles was observed. It was found that its surface was clear and flat, with no obvious dendrite growth.

[0079] Using the negative electrode material 13 prepared in this embodiment as the negative electrode and LiMn2O4 as the positive electrode, a CR2032 full cell was assembled, and its long-term cycling performance was tested at a rate of 0.5C. The test results show that the full cell assembled using negative electrode material 13 exhibits excellent cycling stability, maintaining a capacity of 58 mAh / g after 400 cycles.

[0080] Using the negative electrode material 13 prepared in this embodiment as the negative electrode and LiMn2O4 as the positive electrode, a CR2032 full cell was assembled and cycled for 100 cycles at a rate of 0.5C. After that, the full cell was disassembled and the microstructure of the negative electrode after 100 cycles was observed. It was found that its surface was smooth and zinc was uniformly deposited.

[0081] Example 6

[0082] Based on Example 1, only the freezing time in step (2) of Example 1 was adjusted to 12h, while other conditions and steps were the same as in Example 1. Accordingly, zinc metal anode material modified with ion / electron dual conductor interface film was obtained, which is referred to as anode material 14.

[0083] The negative electrode material 14 prepared in this embodiment was characterized by microstructure. According to the characterization results, the surface of the zinc foil is covered with an interface film with a thickness of about 15 μm, and the surface is flat and orderly.

[0084] According to tests and calculations, the ionic conductivity of the interfacial film in the negative electrode material 14 is 0.45 S / m, and the electronic conductivity is 0.043 S / m.

[0085] The negative electrode material 14 prepared in this embodiment was used as the positive and negative electrodes to assemble a CR 2032 battery, and cycle performance tests were conducted. The test results show that at a current density of 20 mA / cm², the battery performs well. 2 and a capacity of 1mAh / cm 2 Under these conditions, the voltage curve of the negative electrode remains flat after more than 1000 hours, with an overpotential of only 52mV, which is small and has no obvious fluctuations.

[0086] The negative electrode material 14 prepared in this embodiment was used as the positive and negative electrodes to assemble a CR 2032 battery pair, with a current density of 20 mA / cm². 2 and a capacity of 1mAh / cm 2 Under the condition of 100 cycles, the battery was disassembled and the microstructure of the negative electrode after 100 cycles was observed. It was found that its surface was clear and flat, with no obvious dendrite growth.

[0087] Using the negative electrode material 14 prepared in this embodiment as the negative electrode and LiMn2O4 as the positive electrode, a CR2032 full cell was assembled, and its long-term cycling performance was tested at a rate of 0.5C. The test results show that the full cell assembled using negative electrode material 14 exhibits excellent cycling stability, maintaining a capacity of 62 mAh / g after 400 cycles.

[0088] The negative electrode material 14 prepared in this embodiment was used as the negative electrode, and LiMn2O4 was used as the positive electrode. A CR2032 full cell was assembled and cycled for 100 cycles at a rate of 0.5C. After that, the full cell was disassembled and the microstructure of the negative electrode after 100 cycles was observed. It was found that its surface was flat and zinc was uniformly deposited.

[0089] Comparative Example 1

[0090] Pure zinc foil was used as the positive and negative electrodes to assemble CR 2032 batteries, and cycle performance testing was conducted. Figure 7 The test results show that at a current density of 20 mA / cm², 2 and a capacity of 1mAh / cm 2 In this case, the pure zinc foil exhibited a significant short circuit problem after less than 500 hours of cycling, with an overpotential as high as 70mV.

[0091] Pure zinc foil was used as the positive and negative electrodes to assemble a CR 2032 battery pair, with a current density of 20 mA / cm². 2 and a capacity of 1mAh / cm 2 After cycling for 100 cycles, the battery was disassembled, and the microstructure of the pure zinc foil negative electrode after 100 cycles was observed. It was found that its surface morphology was uneven and contained a large number of inactive zinc dendrites, such as... Figure 8 As shown.

[0092] A CR₂O₃₂ full cell was assembled using pure zinc foil as the negative electrode and LiMn₂O₄ as the positive electrode, and its long-term cycling performance was tested at a rate of 0.5C. Figure 5 The test results show that the capacity of the pure zinc foil negative electrode rapidly decays after 180 cycles, and after 200 cycles, the capacity is only 4mAh / g.

[0093] A CR₂O₃₂ full cell was assembled using pure zinc foil as the negative electrode and LiMn₂O₄ as the positive electrode. After 100 cycles at 0.5C, the full cell was disassembled, and the microstructure of the pure zinc foil negative electrode after 100 cycles was observed. Extensive corrosion was found on its surface, such as… Figure 9 As shown.

[0094] Comparative Example 2

[0095] (1) 10 mg Ti3C2T x Add 10mL of deionized water, stir and mix well, then add 50mg of polyvinyl alcohol, then heat to 80℃ and stir to form a viscous slurry;

[0096] (2) After scraping the slurry onto the zinc foil surface with a scraper, freeze it at -20°C for 6 hours, then thaw it at 30°C for 12 hours. Repeat the freezing-thawing operation three times to obtain the zinc metal anode material modified with the interface film, which is referred to as anode material 30.

[0097] The microstructure of the negative electrode material 30 prepared in this comparative example was characterized. According to the characterization results, the surface of the zinc foil is covered with an interface film with a thickness of about 15 μm.

[0098] After testing and calculation, the ionic conductivity of the interfacial film in the negative electrode material 30 is 2×10⁻⁶. -8 S / m, electronic conductivity is 0.035S / m.

[0099] The negative electrode material 30 prepared in this comparative example was used as the positive and negative electrodes to assemble a CR 2032 battery, and its cycle performance was tested. The cycle performance was assessed at a current density of 20 mA / cm². 2 and a capacity of 1mAh / cm 2 In such cases, the voltage of the negative electrode fluctuates significantly after more than 200 hours, resulting in battery damage.

[0100] The negative electrode material 30 prepared in this comparative example was used as the positive and negative electrodes to assemble a CR 2032 battery. The battery was tested at a current density of 20 mA / cm². 2 and a capacity of 1mAh / cm 2 Under the condition of 100 cycles, the battery was disassembled and the microstructure of the negative electrode after 100 cycles was observed. It was found that its surface showed obvious dendrite growth.

[0101] Using the negative electrode material 30 prepared in this comparative example as the negative electrode and LiMn2O4 as the positive electrode, a CR2032 full cell was assembled. Long-term cycling performance was tested at a rate of 0.5C (1C = 148 mAh / g). After 400 cycles, the capacity of the full cell was only 23 mAh / g.

[0102] Using the negative electrode material 30 prepared in this comparative example as the negative electrode and LiMn2O4 as the positive electrode, a CR2032 full cell was assembled and cycled for 100 cycles at a rate of 0.5C. After that, the full cell was disassembled and the microstructure of the PM@Zn negative electrode after 100 cycles was observed. It was found that its surface was uneven and showed obvious corrosion and dendrite growth.

[0103] Comparative Example 3

[0104] (1) Add 20mg Zn(CF3SO3)2 to 10mL of deionized water, stir and mix evenly, then add 50mg polyvinyl alcohol, and then heat to 80℃ and stir to form a viscous slurry.

[0105] (2) After scraping the slurry onto the zinc foil surface with a scraper, freeze it at -20°C for 6 hours, then thaw it at 30°C for 12 hours. Repeat the freezing-thawing operation three times to obtain the zinc metal anode material modified with the interface film, which is referred to as anode material 40.

[0106] The microstructure of the negative electrode material 40 prepared in this comparative example was characterized. According to the characterization results, the surface of the zinc foil is covered with an interface film with a thickness of about 15 μm.

[0107] After testing and calculation, the ionic conductivity of the interfacial film in the negative electrode material 40 is 0.38 S / m, and the electronic conductivity is 3 × 10⁻⁶. -9 S / m.

[0108] The negative electrode material 40 prepared in this comparative example was used as the positive and negative electrodes to assemble a CR 2032 battery, and cycle performance tests were conducted. The current density was 20 mA / cm². 2 and a capacity of 1mAh / cm 2 In this case, the voltage of the negative electrode fluctuates significantly after more than 180 hours, and the battery is damaged.

[0109] The negative electrode material 40 prepared in this comparative example was used as the positive and negative electrodes to assemble a CR 2032 battery. The battery was tested at a current density of 20 mA / cm². 2 and a capacity of 1mAh / cm 2 Under the condition of 100 cycles, the battery was disassembled and the microstructure of the negative electrode after 100 cycles was observed. It was found that its surface showed obvious dendrite growth.

[0110] Using the negative electrode material 40 prepared in this comparative example as the negative electrode and LiMn2O4 as the positive electrode, a CR2032 full cell was assembled. Long-term cycling performance was tested at a rate of 0.5C (1C = 148 mAh / g). After 400 cycles, the capacity of the full cell was only 25 mAh / g.

[0111] Using the negative electrode material 40 prepared in this comparative example as the negative electrode and LiMn2O4 as the positive electrode, a CR2032 full cell was assembled. The cell was cycled for 100 cycles at a rate of 0.5C. After that, the full cell was disassembled and the microstructure of the negative electrode after 100 cycles was observed. It was found that its surface was uneven and showed obvious corrosion and dendrite growth.

[0112] Comparative Example 4

[0113] Based on Example 1, only the Ti3C2T in step (1) of Example 1 is changed. x The mass of Zn(CF3SO3)2 was adjusted to 200 mg and the mass of Zn(CF3SO3)2 was adjusted to 100 mg. Other conditions and steps were the same as in Example 1. Accordingly, an interface film modified zinc metal anode material was obtained, which is referred to as anode material 15.

[0114] The microstructure of the negative electrode material 15 prepared in this comparative example was characterized. According to the characterization results, the surface of the zinc foil is covered with an interface film with a thickness of about 30 μm.

[0115] After testing and calculation, the ionic conductivity of the interfacial film in negative electrode material 15 is 4 × 10⁻⁶. -4 S / m, electronic conductivity 3×10 -6 S / m, this result indicates the addition of excessive Ti3C2T x The presence of Zn(CF3SO3)2 disrupts the overall structure of the interfacial film, significantly reducing the transmission rate of the two conductors.

[0116] The negative electrode material 15 prepared in this comparative example was used as the positive and negative electrodes to assemble a CR 2032 battery, and its cycle performance was tested. The cycle performance was assessed at a current density of 20 mA / cm². 2 and a capacity of 1mAh / cm 2 In this case, the voltage of the negative electrode fluctuates significantly after more than 40 hours, and the battery is damaged.

[0117] The negative electrode material 15 prepared in this comparative example was used as the positive and negative electrodes to assemble a CR 2032 battery. The battery was tested at a current density of 20 mA / cm². 2 and a capacity of 1mAh / cm 2 Under the condition of 100 cycles, the battery was disassembled and the microstructure of the negative electrode after 100 cycles was observed. It was found that its surface showed obvious dendrite growth.

[0118] Using the negative electrode material 15 prepared in this comparative example as the negative electrode and LiMn2O4 as the positive electrode, a CR2032 full cell was assembled. The long-term cycling performance was tested at a rate of 0.5C (1C = 148 mAh / g). After 100 cycles, the capacity of the full cell was only 15 mAh / g.

[0119] Using the negative electrode material 15 prepared in this comparative example as the negative electrode and LiMn2O4 as the positive electrode, a CR2032 full cell was assembled. The cell was cycled for 100 cycles at a rate of 0.5C. After that, the full cell was disassembled and the microstructure of the negative electrode after 100 cycles was observed. It was found that its surface was uneven and showed obvious corrosion and dendrite growth.

[0120] Comparative Example 5

[0121] Based on Example 1, only the freezing-thawing process was removed, and the material was dried at normal room temperature. All other conditions and steps were the same as in Example 1, and a zinc metal anode material modified with an interface film was obtained, which is referred to as anode material 16.

[0122] The microstructure of the negative electrode material 16 prepared in this comparative example was characterized. According to the characterization results, the surface of the zinc foil is covered with an interface film with a thickness of about 10 μm, and obvious curling is observed on the surface.

[0123] After testing and calculation, the ionic conductivity of the interfacial film in negative electrode material 16 is 4 × 10⁻⁶. -4 S / m, electronic conductivity 5×10 -6 S / m.

[0124] The negative electrode material 16 prepared in this comparative example was used as the positive and negative electrodes to assemble a CR 2032 battery, and its cycle performance was tested. The cycle performance was assessed at a current density of 20 mA / cm². 2 and a capacity of 1mAh / cm 2 In such cases, the voltage of the negative electrode fluctuates significantly after more than 50 hours, resulting in battery damage.

[0125] The negative electrode material 16 prepared in this comparative example was used as the positive and negative electrodes to assemble a CR 2032 battery. The battery was tested at a current density of 20 mA / cm². 2 and a capacity of 1mAh / cm 2 Under the condition of 100 cycles, the battery was disassembled and the microstructure of the negative electrode after 100 cycles was observed. It was found that its surface showed obvious dendrite growth.

[0126] Using the negative electrode material 16 prepared in this comparative example as the negative electrode and LiMn2O4 as the positive electrode, a CR2032 full cell was assembled. The long-term cycling performance was tested at a rate of 0.5C (1C = 148 mAh / g). After 100 cycles, the capacity of the full cell was only 23 mAh / g.

[0127] Using the negative electrode material 16 prepared in this comparative example as the negative electrode and LiMn2O4 as the positive electrode, a CR2032 full cell was assembled. The cell was cycled for 100 cycles at a rate of 0.5C. After that, the full cell was disassembled and the microstructure of the negative electrode after 100 cycles was observed. It was found that its surface was uneven and showed obvious corrosion and dendrite growth.

[0128] In summary, the above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. Zinc metal anode material based on ion / electron dual-conductor interface film modification, characterized in that: A zinc-containing metal material with a surface containing an ion / electron dual conductor interface film; The ion / electron dual conductor interface film is a polymer film doped with a conductive material and Zn(CF3SO3)2, with an ionic conductivity of 0.1-0.8 S / m and an electronic conductivity of 0.01-0.1 S / m. The conductive material is MXene, reduced graphene oxide, or heteroatom-doped graphene, and the polymer is one or more of polyvinyl alcohol, polyethylene glycol, polyethylene oxide, and poly(vinylidene fluoride-co-hexafluoropropylene). The mass ratio of the conductive material, Zn(CF3SO3)2, and the polymer is 1:(1-3):(3-8). The preparation method of the zinc metal negative electrode material based on the ion / electron dual conductor interface film modification comprises the following steps: (1) Mix the conductive material, Zn(CF3SO3)2, the polymer, and water, and heat and stir to a thick slurry; (2) After coating the slurry prepared in step (1) on the surface of the zinc-containing metal material, first freeze, then thaw, and repeat the freeze-thaw operation 3-5 times to obtain the zinc metal negative electrode material based on the ion / electron dual conductor interface film modification.

2. The zinc metal anode material based on ion / electron dual conductor interface film modification according to claim 1, characterized in that: MXene is selected from Ti3C2T x or Ti3AlC2.

3. The zinc metal anode material based on ion / electron dual conductor interface film modification according to claim 1 or 2, characterized in that: The thickness of the ion / electron dual conductor interface film is 200 nm-40 μm.

4. The method for preparing a zinc metal negative electrode material based on an ion / electron dual conductor interface film modification according to any one of claims 1 to 3, characterized by: The preparation method comprises the following steps: (1) Mix the conductive material, Zn(CF3SO3)2, the polymer, and water, and heat and stir to a thick slurry; (2) After coating the slurry prepared in step (1) on the surface of the zinc-containing metal material, first freeze, then thaw, and repeat the freeze-thaw operation 3-5 times to obtain the zinc metal negative electrode material based on the ion / electron dual conductor interface film modification.

5. The method of claim 4, wherein the method is characterized by: In step (1), the concentration of the conductive material in the slurry is 1-5 mg / mL.

6. The method of claim 4, wherein the method is characterized by: In step (1), stir at 60-90°C to a thick slurry.

7. The method according to claim 4, wherein the method is characterized by: In step (2), the temperature for each freezing is -40 to -20°C and the freezing time is 30 min-24 h, and the temperature for each thawing is 20-40°C and the thawing time is 2-24 h.

8. The zinc metal negative electrode material based on the ion / electron dual conductor interface film modification for use as a negative electrode in a water-based zinc ion battery according to any one of claims 1-3.

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