Preparation method and application of zinc ion battery anode material based on nanocellulose fibrils and cellulose nanocrystals

Abstract

The present invention discloses a method for preparing a zinc ion battery anode material based on nanocellulose fibrils and cellulose nanocrystals and its application, belonging to the field of polymer nanocomposite materials. The method for preparing a zinc ion battery anode material of the present invention comprises the following steps: mixing zinc powder, carbon nanotubes, nanocellulose fibrils, cellulose nanocrystals and water to obtain a precursor solution; filtering the precursor solution to obtain a filter membrane, freeze-drying, and pressurizing to obtain the zinc ion battery anode material. The present invention uses nanocellulose fibrils and cellulose nanocrystals as raw materials and optimizes the corresponding preparation scheme to give the product a unique nanostructure, forming a three-dimensional porous conductive network, thereby significantly enhancing the contact area between the electrode material and the electrolyte, and promoting Zn 2+ The rapid diffusion and uniform deposition of the nanostructured carbon have a positive impact on improving the Coulombic efficiency and extending the cycle life of the battery.

Description

Technical Field

[0001] The present invention relates to the field of polymer nanocomposite materials, and in particular to a preparation method and application of a zinc ion battery anode material based on nanocellulose fibrils and cellulose nanocrystals. Background Art

[0002] In recent years, zinc-ion batteries have been widely used due to their high theoretical specific capacity (820 mAh g -1 ) and a low redox potential (−0.762 V vs. SHE, standard hydrogel electrodes), zinc metal anodes have attracted widespread attention in the field of energy storage and conversion. However, zinc metal anodes face persistent challenges with dendrite growth and water-induced corrosion, which severely compromise the reversibility and cycling stability of zinc anodes in zinc-ion batteries (AZIBs). Zn dendrite formation typically stems from uneven zinc deposition on the metal anode. This unevenness can be caused by uneven electric field distribution and the formation of a heterogeneous solid electrolyte interface (SEI) resulting from organic electrolyte decomposition. Due to the hexagonal close-packed (hcp) structure of zinc, the (0002) crystal plane is preferentially exposed, resulting in a convex surface on the metal anode. The presence of this convex surface favors zinc ions to accumulate at the top of the convex surface during deposition, creating the so-called "tip effect." Excessive dendrite growth can result in thick, sharp dendrites that can penetrate the battery separator, causing short circuits and failure. Even in the early stages of dendrite growth, it can promote the formation of zinc sulfate hydroxide (ZSH) and the hydrogen evolution reaction on the anode side. The production of the inert byproduct ZSH forms a passivation layer on the electrode surface, exacerbating the dendrite problem. The generation of hydrogen is generally detrimental to battery performance. To address the interfacial stability issue of zinc metal anodes in aqueous zinc-ion batteries in practical applications, dendrites can be reduced by preparing surface modification layers, such as carbon nanotubes (CNTs), GO, reduced graphene oxide (rGO), and graphite. These layers can distribute a portion of the negative electrode charge, resulting in higher electrochemical activity.

[0003] The combination of carbon nanotubes and zinc powder alone has poor mechanical properties and is unable to form a film. This problem is typically addressed by adding a binder (such as carboxymethyl cellulose (CMC) or polyvinylidene fluoride (PVDF), optimizing the ratio of CNTs to zinc powder, and performing surface modification (such as oxidation, reduction, or grafting functionalization). Therefore, improving the mechanical strength and electrochemical performance of the zinc metal anode is key to developing high-performance zinc-ion batteries. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for preparing a zinc ion battery anode material based on nanocellulose fibrils and cellulose nanocrystals and its application to solve the above-mentioned problems in the background technology. The present invention uses nanocellulose fibrils and cellulose nanocrystals as raw materials and optimizes the corresponding preparation scheme to give the product a unique nanostructure, forming a three-dimensional porous conductive network, thereby significantly increasing the contact area between the electrode material and the electrolyte, and promoting the Zn 2+ The rapid diffusion and uniform deposition of the nanostructured carbon have a positive impact on improving the Coulombic efficiency and extending the cycle life of the battery.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] One of the technical solutions of the present invention is to provide a method for preparing a zinc ion battery anode material, comprising the following steps:

[0007] Zinc powder, carbon nanotubes (CNTs), cellulose nanofibrils (CNFs), cellulose nanocrystals (CNCs) and water (DI) were mixed to obtain a precursor solution;

[0008] The precursor solution is filtered to obtain a filter membrane, which is freeze-dried and pressure-treated to obtain the zinc ion battery anode material.

[0009] Preferably, the method of mixing zinc powder, carbon nanotubes, nanocellulose fibrils, cellulose nanocrystals and water is: mixing nanocellulose fibrils and cellulose nanocrystals to obtain a suspension, then dropping the suspension into the carbon nanotube aqueous solution under stirring conditions, and then adding zinc powder, stirring and ultrasonically crushing the suspension.

[0010] Preferably, the ultrasonic crushing power ratio is 70%, the crushing mode is on for 2 seconds and off for 1 second, and the total crushing time is 60 minutes.

[0011] The ultrasonic crushing of the present invention can improve dispersibility and uniformity.

[0012] Preferably, the size range of the zinc powder is 15-53 μm; the length range of the carbon nanotubes is 0.5-2 μm, and the diameter range is 10-20 nm; the length range of the nanocellulose fibrils is 5-10 μm; and the diameter range of the cellulose nanocrystals is 100-200 nm.

[0013] Preferably, the ratio of the total mass of the zinc powder, carbon nanotubes, nanocellulose fibrils and cellulose nanocrystals to water is 450-500 mg:45-55 mL; the mass ratio of the total mass of the nanocellulose fibrils and cellulose nanocrystals to the zinc powder and carbon nanotubes is 1:8:1; and the mass ratio of the nanocellulose fibrils to the cellulose nanocrystals is 4-9:1.

[0014] Preferably, the mass ratio of the nanocellulose fibrils to the cellulose nanocrystals is 8:1.

[0015] Preferably, the filtering method is vacuum filtration.

[0016] Preferably, the freeze-drying cold trap temperature is -60°C and the time is 24 hours.

[0017] Preferably, the pressure of the pressurization treatment is 10 MPa.

[0018] The main functions of the pressure treatment of the present invention are to improve the filtration efficiency, shorten the filtration time, and promote the separation and purification of the filtrate.

[0019] The second technical solution of the present invention is to provide a zinc ion battery anode material obtained according to the above preparation method.

[0020] Preferably, the conductivity of the zinc ion battery anode material is 847-1250 S / m, and the specific surface area is 29-38m 2 / g.

[0021] The third technical solution of the present invention is to provide an application of the above-mentioned zinc ion battery anode material in the preparation of a zinc ion battery.

[0022] Preferably, the zinc ion battery is a symmetrical battery, a coin battery or a flexible battery.

[0023] The technical principles of the present invention are as follows:

[0024] The present invention prepares a Zn / carbon nanotube / nanocellulose fibril / cellulose nanocrystal composite aerogel film by adjusting the mixing method and ratio of zinc powder, carbon nanotubes, nanocellulose fibrils and cellulose nanocrystals, and performing directional freezing and vacuum freeze-drying after vacuum filtration. A three-dimensional conductive network is constructed through the CNF, CNC and CNT in the aerogel.

[0025] Compared to traditional solutions using zinc powder and carbon nanotubes as raw materials, the present invention incorporates cellulose nanofibrils and cellulose nanocrystals, creating more hydrogen bonding sites and imparting a unique nanoscale structure. This allows for the construction of multiple reversible conductive networks, enhancing the mechanical properties of the resulting aerogel. This nanostructure homogenizes the interfacial electric field and provides electron transfer pathways, improving the membrane's electronic conductivity and boosting charge transfer efficiency.

[0026] Experiments have shown that omitting CNF and CNC reduces the mechanical properties of the mixed hydrogel, making it difficult to form a membrane and resulting in poor sensing performance. Omitting CNF alone results in a nearly powdery membrane after filtration, making it difficult to exfoliate and form a membrane, thus preventing the final product from being prepared.

[0027] In addition, the ratio of CNF and CNC in the present invention also needs to be specifically limited. When the mass ratio of nanocellulose fibrils to cellulose nanocrystals is higher or lower than 8:1, the product produces relatively more dendrites after recycling and has poor recycling performance.

[0028] When the zinc ion battery anode material of the present invention is prepared into a symmetrical battery, the cycle efficiency of 6000 cycles is close to 100%, and the cycle performance is excellent.

[0029] The beneficial technical effects of the present invention are as follows:

[0030] The present invention uses nanocellulose fibrils and cellulose nanocrystals as raw materials and optimizes the corresponding preparation scheme to give the product a unique nanostructure and form a three-dimensional porous conductive network, thereby significantly increasing the contact area between the electrode material and the electrolyte and promoting the Zn 2+ The rapid diffusion and uniform deposition of Zn have a positive impact on improving the battery's Coulombic efficiency and extending its cycle life. Furthermore, this nanostructure provides ample space for Zn volume changes, effectively reducing dendrite formation, thereby improving the electrode's cycling stability and reversibility, resulting in the product of this invention possessing excellent conductivity and high cycle efficiency. Furthermore, the three-dimensional conductive network structure constructed by incorporating CNFs and CNCs effectively suppresses the hydrogen evolution side reaction and the production of inert byproducts, reducing electrolyte consumption and positively impacting the battery's Coulombic efficiency and extending its cycle life. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0032] Figure 1 This is a macroscopic physical picture of the filter membrane in Comparative Example 1.

[0033] Figure 2 Figure 2 is a photo of the bending test of the zinc ion battery anode material in Example 2. Figure a is a photo before bending, b and c are photos of the material at different angles during the bending process, and d is a photo after bending.

[0034] Figure 3 The charge and discharge cycle test data of the symmetrical battery prepared with the products of Examples 1-4.

[0035] Figure 4The following are SEM images of the anode material of a symmetrical battery prepared with the products of Example 2 and Example 3 after 6000 cycles. Here, a is Example 2, and b is Example 3.

[0036] Figure 5 Schematic diagram of the cycle efficiency of symmetrical batteries prepared using the products of Examples 1-4.

[0037] Figure 6 This is the SEM image of the zinc ion battery anode material in Example 1. DETAILED DESCRIPTION

[0038] Various exemplary embodiments of the present invention are now described in detail. This detailed description should not be considered as a limitation of the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention. It should be understood that the terms used in the present invention are only for describing specific embodiments and are not intended to limit the present invention.

[0039] In addition, for numerical ranges in the present invention, it is understood that each intervening value between the upper and lower limits of the range is also specifically disclosed. Each smaller range between any stated value or stated range, and any other stated value or intervening value in the stated range, is also included in the present invention. The upper and lower limits of these smaller ranges may independently be included or excluded in the range.

[0040] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention pertains. Although preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of the present invention.

[0041] The terms “include,” “including,” “have,” “contain,” etc. used in the present invention are open-ended terms, meaning including but not limited to.

[0042] The size range of the zinc powder used in the following embodiments and comparative examples of the present invention is 34 μm; the length range of the carbon nanotubes is 1.3 μm, and the diameter range is 15 nm; the length range of the nanocellulose fibrils is 7.5 μm; and the diameter range of the cellulose nanocrystals is 150 nm.

[0043] The raw materials used in the following examples and comparative examples of the present invention are all commercially available products.

[0044] Example 1

[0045] A method for preparing a zinc ion battery anode material:

[0046] Prepare a total mass of 500 mg of zinc powder, carbon nanotubes (CNTs), cellulose nanofibrils (CNFs), and cellulose nanocrystals (CNCs) (the mass ratio of the total mass of CNFs and CNCs to the mass of zinc powder and CNTs is 1:8:1, and the mass ratio of CNFs and CNCs is 4:1). First, disperse the cellulose nanofibrils and cellulose nanocrystals in 25 mL of deionized water and mix well to obtain a suspension. Then, disperse the carbon nanotubes in 25 mL of deionized water and mix well to obtain a carbon nanotube aqueous solution. Then, drop the carbon nanotube aqueous solution into the suspension under stirring conditions. Then, add zinc powder, stir, and ultrasonically disrupt the mixture (the ultrasonic disruption power ratio is 70%, the disruption mode is on for 2 seconds, off for 1 second, and the total disruption time is 60 minutes) to obtain a precursor solution.

[0047] The precursor solution was vacuum filtered, and the obtained filter membrane was peeled off from the filter membrane, and then placed in an ultra-low temperature refrigerator and frozen at -45°C for 24 hours, and then freeze-dried (cold trap temperature -60°C, time 24 hours, vacuum degree of 10Pa), and then pressurized at 10 MPa to obtain the zinc ion battery anode material.

[0048] Figure 6 This is the SEM image of the zinc ion battery anode material in Example 1.

[0049] Depend on Figure 6 It can be seen that the cross-section of the zinc ion battery anode material prepared in this embodiment is a layered structure, and zinc balls are embedded in a plane interwoven with carbon nanotubes, nanocellulose fibrils and cellulose nanocrystals.

[0050] Example 2

[0051] A method for preparing a zinc ion battery anode material:

[0052] Prepare a total mass of 500 mg of zinc powder, carbon nanotubes (CNTs), cellulose nanofibrils (CNFs), and cellulose nanocrystals (CNCs) (wherein the mass ratio of the total mass of CNFs and CNCs to the mass of zinc powder and CNTs is 1:8:1, and the mass ratio of CNFs and CNCs is 6:1). First, disperse the cellulose nanofibrils and cellulose nanocrystals in 25 mL of deionized water and mix well to obtain a suspension. Then, disperse the carbon nanotubes in 25 mL of deionized water and mix well to obtain a carbon nanotube aqueous solution. Then, dropwise add the carbon nanotube aqueous solution to the suspension under stirring conditions, add zinc powder, stir, and ultrasonically disrupt the suspension (the ultrasonic disruption power ratio is 70%, the disruption mode is on for 2 seconds, off for 1 second, and the total disruption time is 60 minutes).

[0053] The precursor solution was vacuum filtered, and then the obtained filter membrane was peeled off from the filter membrane, freeze-dried (cold trap temperature -60°C, time 24h, vacuum degree 10Pa), and then pressurized at 10 MPa to obtain the zinc ion battery anode material.

[0054] Example 3

[0055] A method for preparing a zinc ion battery anode material:

[0056] Prepare a total mass of 500 mg of zinc powder, carbon nanotubes (CNTs), cellulose nanofibrils (CNFs), and cellulose nanocrystals (CNCs) (wherein the mass ratio of the total mass of CNFs and CNCs to the mass of zinc powder and CNTs is 1:8:1, and the mass ratio of CNFs to CNCs is 8:1). First, disperse the cellulose nanofibrils and cellulose nanocrystals in 25 mL of deionized water and mix well to obtain a suspension. Then, disperse the carbon nanotubes in 25 mL of deionized water and mix well to obtain a carbon nanotube aqueous solution. Then, dropwise add the carbon nanotube aqueous solution to the suspension under stirring conditions, add zinc powder, stir, and ultrasonically disrupt the suspension (the ultrasonic disruption power ratio is 70%, the disruption mode is on for 2 seconds, off for 1 second, and the total disruption time is 60 minutes).

[0057] The precursor solution was vacuum filtered, and then the obtained filter membrane was peeled off from the filter membrane, freeze-dried (cold trap temperature -60°C, time 24h, vacuum degree 10Pa), and then pressurized at 10 MPa to obtain the zinc ion battery anode material.

[0058] The zinc-ion battery anode material prepared in Example 3 was analyzed using cyclic voltammetry (CV) curves to investigate its kinetic behavior. The CV curves were found to be consistent with the GCD profile. Furthermore, as the scan rate increased, the peak current increased accordingly, and the CV curve maintained its integrity.

[0059] Example 4

[0060] A method for preparing a zinc ion battery anode material:

[0061] Prepare a total mass of 500 mg of zinc powder, carbon nanotubes (CNTs), cellulose nanofibrils (CNFs), and cellulose nanocrystals (CNCs) (wherein the mass ratio of the total mass of CNFs and CNCs to the mass of zinc powder and CNTs is 1:8:1, and the mass ratio of CNFs and CNCs is 9:1). First, disperse the cellulose nanofibrils and cellulose nanocrystals in 25 mL of deionized water and mix well to obtain a suspension. Then, disperse the carbon nanotubes in 25 mL of deionized water and mix well to obtain a carbon nanotube aqueous solution. Then, dropwise add the carbon nanotube aqueous solution to the suspension under stirring conditions, add zinc powder, stir, and ultrasonically disrupt the suspension (the ultrasonic disruption power ratio is 70%, the disruption mode is on for 2 seconds, off for 1 second, and the total disruption time is 60 minutes).

[0062] The precursor solution was vacuum filtered, and then the obtained filter membrane was peeled off from the filter membrane, freeze-dried (cold trap temperature -60°C, time 24h, vacuum degree 10Pa), and then pressurized at 10 MPa to obtain the zinc ion battery anode material.

[0063] By observing the cross-sections of the zinc powder / carbon nanotube / nanocellulose fibril (CNF) / cellulose nanocrystal (CNC) composite zinc ion battery anode material prepared in Example 4 before and after cycling, it was clearly found that the zinc ion battery anode became significantly thicker after cycling.

[0064] Comparative Example 1 (omitting the addition of nanocellulose fibrils and nanocellulose crystals and supplementing with an equal mass of carbon nanotubes)

[0065] Disperse 500 mg of zinc powder and carbon nanotubes (CNTs) in 50 mL of deionized water (the mass ratio of zinc powder to CNTs is 8:1) and mix well to obtain a precursor solution.

[0066] The precursor solution was vacuum filtered to obtain a filter membrane. Since the obtained filter membrane system was almost powdery and difficult to be normally peeled off from the filter membrane, subsequent freeze-drying and other operations were not performed.

[0067] Figure 1 This is a physical picture of the filter membrane in Comparative Example 1.

[0068] Depend on Figure 1 It can be seen that without adding CNF and CNC, the filter membrane system obtained after filtration is almost powdery, which is difficult to peel off and form a membrane normally, and it is impossible to prepare the final product.

[0069] Effect verification

[0070] 1. The zinc ion battery anode material prepared in Example 2 was subjected to a 90° repeated bending test, which was repeated 5 times in total.

[0071] Figure 2Figure 2 is a photo of the bending test of the zinc ion battery anode material in Example 2. Figure a is a photo before bending, b and c are photos of the material at different angles during the bending process, and d is a photo after bending.

[0072] Depend on Figure 2 It can be seen that after the folding test, the product did not produce significant geometric deformation.

[0073] After coin battery assembly, it showed a high cycle retention rate of no less than 98% after 1500 cycles.

[0074] 2. The zinc ion battery anode materials of each embodiment and comparative example were assembled into batteries, and their corresponding electrochemical properties were tested.

[0075] Assembly of symmetrical batteries:

[0076] A symmetrical CR2032 coin cell was assembled using two zinc-ion battery anode materials (ZTFC) as electrodes and 0.2M ZnSO₄ and 0.2M MnSO₄ as electrolytes. A glass cellulose membrane with a diameter of approximately 19 mm was used as the separator. Before electrochemical testing, the assembled cell was air-conditioned for 10 hours to stabilize its performance and facilitate testing.

[0077] Assembly of coin-type aqueous zinc-ion batteries (Azibs):

[0078] To prepare the cathode, a slurry consisting of γ-MnO2 (70 wt%), carbon black (20 wt%), and polyvinylidene fluoride (PVDF) (10 wt%) dispersed in N-methylpyrrolidone solvent was coated on nickel foam, dried at 60°C for 24 hours, and then pressurized at 10 MPa. Coin cells were assembled using ZTFC as the anode, a glass cellulose membrane with a diameter of approximately 19 mm as the separator, and a mixed aqueous solution containing 0.2 M ZnSO4 and 0.2 M MnSO4 as the electrolyte. 200 mL of the electrolyte was added to each coin-shaped aqueous zinc-ion battery.

[0079] Figure 3 The charge and discharge cycle test data of the symmetrical battery prepared with the products of Examples 1-4.

[0080] Figure 3 In the embodiment 1, CNF:CNC=4:1 represents Example 1, CNF:CNC=6:1 represents Example 2, CNF:CNC=8:1 represents Example 3, and CNF:CNC=9:1 represents Example 4.

[0081] Figure 4 The following are SEM images of the anode material of a symmetrical battery prepared with the products of Example 2 and Example 3 after 6000 cycles. Here, a is Example 2, and b is Example 3.

[0082] Figure 5 Schematic diagram of the cycle efficiency of symmetrical batteries prepared using the products of Examples 1-4.

[0083] Figure 5 Among them, 4:1 represents Example 1, 6:1 represents Example 2, 8:1 represents Example 3, and 9:1 represents Example 4.

[0084] Depend on Figure 3 It can be seen that when the current density is stable at 0.5mA / cm 2 When the product of Example 3 was cycled for 6000 times, the voltage was stable, while at other CNF:CNC ratios, the voltage fluctuated significantly. This may be because other products would produce a large number of dendrites during the cycle ( Figure 4 a is Example 2, Figure 4 b is Example 3), which reduces the stability of the battery.

[0085] Depend on Figure 5 It can be seen that the zinc ion battery anode material prepared in Example 3 has the best cycle efficiency and cycle stability when assembled into coin batteries compared with the products of other examples, maintaining a cycle efficiency of 98% and a capacity retention rate of 99%.

[0086] In summary, the three-dimensional conductive skeleton structure of the product of the present invention uniformizes the electric field at the interface, facilitating electron transfer, thereby enhancing the electronic conductivity of the film and accelerating charge transfer. Batteries prepared with the product of the present invention have been measured to exhibit high Coulombic efficiency, good cycle performance and reversibility, and no significant polarization during charge and discharge.

[0087] ZTFC anodes with different proportions deformed to varying degrees after cycling. After cycling, the Zn on the surface of the product of Example 3 grew in an orderly manner in the horizontal direction (epitaxial growth) and the vertical direction, achieving dense, uniform, dendrite-free Zn deposition and growth, and the surface remained relatively smooth; while other surfaces became relatively rough and thicker. The formation of dendrites first decreased and then increased. By optimizing the addition ratio of CNF and CNC, the pore structure and wettability of the product were improved, and the diffusion and deposition ability of zinc were enhanced. This is mainly because, at this ratio, the change in local current density during the galvanizing process is minimized, effectively preventing the early growth of zinc dendrites; while an inappropriate ratio leads to a denser electrode structure, reduces the active reaction area, hinders the electrolyte-electrode interaction, and thus promotes the formation of zinc dendrites.

[0088] The embodiments described above are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by persons skilled in the art should fall within the scope of protection defined by the claims of the present invention.

Claims

1. A method for preparing a zinc ion battery anode material, characterized in that: The following steps are involved: mixing zinc powder, carbon nanotubes, nanocellulose fibrils, cellulose nanocrystals and water to obtain a precursor solution; Filtering the precursor solution to obtain a filter membrane, freeze-drying, and pressure-treating to obtain the zinc ion battery anode material; The size range of the zinc powder is 15-53µm; the length range of the carbon nanotubes is 0.5-2µm, and the diameter range is 10-20nm; the length range of the nanocellulose fibrils is 5-10µm; and the diameter range of the cellulose nanocrystals is 100-200nm. The ratio of the total mass of the zinc powder, carbon nanotubes, nanocellulose fibrils and cellulose nanocrystals to water is 450-500 mg:45-55 mL; the mass ratio of the total mass of the nanocellulose fibrils and cellulose nanocrystals to the zinc powder and carbon nanotubes is 1:8:1; the mass ratio of the nanocellulose fibrils to the cellulose nanocrystals is 4-9:1; The cross section of the zinc ion battery anode material is a layered structure, and zinc balls are embedded in a plane interwoven with carbon nanotubes, nanocellulose fibrils and cellulose nanocrystals.

2. The preparation method according to claim 1, characterized in that The mass ratio of the nanocellulose fibrils to the cellulose nanocrystals is 8:

1.

3. The preparation method according to claim 1, characterized in that The filtering method is vacuum filtration.

4. The preparation method according to claim 1, characterized in that The cold trap temperature of the freeze drying is -60°C and the time is 24 hours.

5. The preparation method according to claim 1, characterized in that The pressure of the pressurization treatment is 10 MPa.

6. A zinc ion battery anode material obtained according to the preparation method according to any one of claims 1-2.

7. The zinc ion battery anode material according to claim 6, wherein The conductivity of the zinc ion battery anode material is 847-1250 S / m, and the specific surface area is 29-38m 2 / g.

8. Use of the zinc ion battery anode material according to claim 6 or 7 in the preparation of a zinc ion battery.

Images