Preparation method of zinc alloy negative material and zinc ion battery

Abstract

This invention relates to a method for preparing a zinc alloy anode material and a zinc-ion battery, comprising the following steps: casting the alloyed melt into a mold, crushing, ball milling, and sieving to obtain zinc alloy powder; mixing the zinc alloy powder with graphene and an organic binder in a volume ratio of 6-9:1-2:1-2, and ball milling to obtain a Zn-C mixture; wherein the proportion of zinc alloy powder in the Zn-C mixture is ≥60 vol%, and the total proportion of graphene and organic binder in the Zn-C mixture is ≤40 vol%; mixing the Zn-C mixture with an organic solvent uniformly to obtain a slurry; coating the slurry onto a template, drying, and cutting to obtain the zinc alloy anode material. The zinc alloy anode material of this invention, when applied to a zinc-ion battery, exhibits excellent cycle performance and a longer battery life. The process of this invention is simple, the preparation cost is low, and it facilitates widespread application.

Description

Technical Field

[0001] This invention relates to a method for preparing a zinc alloy negative electrode material and a zinc-ion battery, belonging to the field of zinc alloy electrode materials. Background Technology

[0002] Zinc-ion batteries, due to their inherent safety, low raw material costs, and simple manufacturing process, have already been applied in the energy storage field. However, factors such as dendrites and passivation films in zinc batteries reduce their lifespan and electrochemical performance. Currently, these problems cannot be completely eliminated, but the formation of dendrites and negative reactions can be delayed or reduced as much as possible, thereby greatly improving the lifespan and electrochemical performance of zinc batteries, enhancing their commercial value, and providing strong technical support for large-scale promotion.

[0003] Chinese invention patent application CN201910907323.1 discloses a composite current collector for zinc-based batteries, comprising a zinc substrate and a conductive layer attached to the zinc substrate. The zinc substrate is zinc, a zinc alloy, or galvanized metal. The conductive layer comprises metal powder and a binder. The metal powder is at least one selected from copper powder, tin powder, magnesium powder, calcium powder, zinc powder, titanium powder, manganese powder, indium powder, lead powder, cadmium powder, palladium powder, bismuth powder, tungsten powder, and vanadium powder. The conductive layer also includes a conductive agent, which is at least one selected from graphite, acetylene black, graphene, carbon fiber, carbon nanotubes, and carbon fiber spheres. While this technology forms a protective layer on the zinc substrate surface, increasing the difficulty of corrosion and extending the stability of the current collector structure, thus improving the battery's cycle performance, a significant contact interface exists between the zinc substrate and the conductive layer, increasing the defect rate or the possibility of defects occurring during service. In addition, metal powders such as manganese powder and vanadium powder exist in elemental form and have a large potential difference with zinc. When they are wetted by electrolyte, they form micro-galvanic corrosion, which easily leads to strong self-corrosion. The negative electrode structure is prone to collapse and hydrogen gas is generated, which will reduce the battery life. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the purpose of this invention is to provide a method for preparing zinc alloy anode material, which can be used to assemble zinc batteries and improve the cycle performance of zinc-ion batteries; a second purpose of this invention is to provide a zinc-ion battery.

[0005] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows:

[0006] A method for preparing a zinc alloy negative electrode material includes the following steps:

[0007] S1. Provide alloying melt;

[0008] The alloying melt is composed of zinc and alloying components; the alloying components account for 10-40 wt% of the alloying melt, and the alloying components include indium, bismuth, tin, graphene, and carbon nanotubes; in the alloying melt, the content of indium is 1-20%, the content of bismuth is 3-15%, the content of tin is 0.5-9%, the content of graphene is 0.03-0.07%, and the content of carbon nanotubes is 0.03-0.07%.

[0009] S2. After the alloyed melt is cast into a shape, it is crushed, ball-milled, and sieved to obtain zinc alloy powder.

[0010] S3. The zinc alloy powder is mixed with graphene and organic binder in a volume ratio of 6-9:1-2:1-2, and ball-milled to obtain a Zn-C mixture.

[0011] Among them, the proportion of zinc alloy powder in Zn-C mixture is ≥60 vol%, and the total proportion of graphene and organic binder in Zn-C mixture is ≤40 vol%.

[0012] S4. Mix the Zn-C mixture with an organic solvent until homogeneous to obtain a slurry;

[0013] S5. The slurry is coated onto a template, dried, and then cut to obtain a zinc alloy negative electrode material.

[0014] Furthermore, in S1, the proportion of alloying components in the alloying melt is 15-30 wt%, preferably 18-25 wt%; preferably, the temperature of the alloying melt is 580-650℃, more preferably 590-610℃.

[0015] Further, in S1, the alloying composition consists of aluminum, indium, bismuth, tin, RE, copper, titanium, magnesium, gallium, graphene, carbon nanotubes, and yttrium oxide; in the alloying melt, the content of aluminum is 0.3-0.7%, the content of indium is 1-20%, the content of bismuth is 3-15%, the content of tin is 0.5-9%, the content of RE is 0.09-0.21%, the content of copper is 0.03-0.07%, the content of titanium is 0.03-0.07%, the content of magnesium is 0.03-0.07%, the content of gallium is 0.03-0.07%, the content of graphene is 0.03-0.07%, the content of carbon nanotubes is 0.03-0.07%, and the content of yttrium oxide is 0.03-0.07%; RE is selected from one or more of cerium, samarium, and ytterbium.

[0016] Further, in S1, the alloyed melt contains 0.4-0.6% aluminum, 2-19% indium, 4-14% bismuth, 0.8-8.5% tin, 0.12-0.18% RE, 0.04-0.06% copper, 0.04-0.06% titanium, 0.04-0.06% magnesium, 0.04-0.06% gallium, 0.04-0.06% graphene, and carbon nanotubes. The content is 0.04-0.06%, and the yttrium oxide content is 0.04-0.06%; preferably, RE is composed of cerium, samarium, and ytterbium, and the mass ratio of cerium, samarium, and ytterbium is 1-2:1-2:1-2. Optionally, in the alloying melt, the cerium content is 0.03-0.07%, preferably 0.04-0.06%; the samarium content is 0.03-0.07%, preferably 0.04-0.06%; and the ytterbium content is 0.03-0.07%, preferably 0.04-0.06%.

[0017] Furthermore, in S2, the cast zinc alloy is crushed into particles smaller than 1 cm, preferably smaller than 0.5 cm.

[0018] Furthermore, in S2, the particle size of the zinc alloy powder is ≤30μm.

[0019] Furthermore, in S3, an all-around planetary ball mill is used for ball milling, controlling the rotational speed of the ball mill jar to be 350-450 rpm and the common rotational speed of the ball mill jar to be 10-20 rpm. The ball milling is stopped for 1-3 minutes every 4-6 minutes, and the cycle is repeated 3-5 times.

[0020] Furthermore, in S3, the volume ratio of the zinc alloy powder to graphene and organic binder is 7-8:1-2:1-2, and preferably, the organic binder is PVDF.

[0021] Further, in S4, the mass-to-volume ratio of the Zn-C mixture to the organic solvent is 1-2 g: 5-10 mL; preferably, the organic solvent is NMP; preferably, the Zn-C mixture and the organic solvent are mixed and stirred at 50-70°C for 10-18 h to obtain a slurry.

[0022] Furthermore, in S5, the coating thickness is 500-800 μm.

[0023] Furthermore, in S5, the thickness of the zinc alloy negative electrode material is 60-120 μm, preferably 80-100 μm, and more preferably 85-95 μm.

[0024] Preferably, the template is a glass plate.

[0025] Furthermore, in S5, the sample is vacuum dried at 50-70℃ for 2-4 hours.

[0026] Based on the same inventive concept, the present invention also provides: a zinc-ion battery, comprising a zinc alloy negative electrode material prepared by the preparation method described above.

[0027] The metal alloying and ball milling mixing process employed in this invention solves the problems of pure zinc powder easily forming dendrites and reacting too quickly with the electrolyte. The ball milling mixing process also addresses the shortcomings of zinc alloy thin-film preparation, such as difficulty in forming the zinc alloy thin film, challenges in alloy element mixing, and uneven element distribution. In the later stages, the ball milling mixing process is used to prepare a Zn-C mixture. During ball milling, the zinc alloy powder and graphene are further compounded, further reducing the specific gravity of the zinc alloy powder. This prevents the heavier zinc alloy powder from stratifying in the negative electrode material slurry, contributing to the subsequent acquisition of a zinc alloy negative electrode material with a uniform composition distribution. The combination of these two processes facilitates the large-scale, low-cost production of zinc-ion batteries.

[0028] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0029] (1) The zinc alloy negative electrode material of the present invention is applied to zinc-ion batteries and exhibits excellent cycle performance and longer battery service life.

[0030] (2) The process of the present invention is simple and the preparation cost is low, which helps to promote its application. Attached Figure Description

[0031] Figure 1 This is a charge-discharge curve of the symmetrical battery in Example 1.

[0032] Figure 2 This is a charge-discharge curve of the symmetrical battery in Example 2.

[0033] Figure 3 This is a charge-discharge curve of the symmetrical battery in Example 3.

[0034] Figure 4 This is a symmetrical battery charge-discharge curve diagram for Comparative Example 1.

[0035] Figure 5 This is a symmetrical battery charge-discharge curve diagram for Comparative Example 2.

[0036] Figure 6 This is a comparison of the full battery charge-discharge curves of Examples 1-3.

[0037] Figure 7 This is a digital photograph of the zinc alloy powder in Example 2.

[0038] Figure 8 This is a digital photograph of the zinc alloy negative electrode material of Example 1. Detailed Implementation

[0039] The present invention will be described in detail below with reference to embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in the embodiments of the present invention can be combined with each other. Unless otherwise specified, the relevant percentages refer to mass percentages.

[0040] Example 1

[0041] The preparation method of the zinc alloy negative electrode material in this embodiment includes the following steps:

[0042] S1. The raw material is melted in a 1Kg smelting furnace and alloyed at 600℃ to obtain an alloyed melt at 600℃.

[0043] The alloying melt is composed of zinc and alloying components. The alloying components account for 10 wt% of the alloying melt. The alloying components consist of aluminum, indium, bismuth, tin, RE, copper, titanium, magnesium, gallium, graphene, carbon nanotubes, and yttrium oxide. The RE is composed of cerium, samarium, and ytterbium. In the alloying melt, the content of aluminum is 0.5%, indium is 3%, bismuth is 5%, tin is 1%, cerium is 0.05%, samarium is 0.05%, ytterbium is 0.05%, copper is 0.05%, titanium is 0.05%, magnesium is 0.05%, gallium is 0.05%, graphene is 0.05%, carbon nanotubes are 0.05%, and yttrium oxide is 0.05%.

[0044] S2. After the alloyed melt is cast into 20 molds with a diameter of 3cm, it is crushed into particles smaller than 0.5cm by a crusher, ball-milled to obtain powder, and then sieved with a molecular sieve to obtain zinc alloy powder with a diameter of 1-30μm.

[0045] S3. The zinc alloy powder is mixed with graphene and organic binder (PVDF, AKEMAHSV900) in a volume ratio of 8:1:1, and then ball-milled in an all-around planetary ball mill to obtain a Zn-C mixture.

[0046] During ball milling, the rotational speed of the ball mill jar is controlled at 400 rpm, and the rotational speed of the ball mill jar is controlled at 15 rpm. The ball milling is stopped for 2 minutes every 5 minutes, and the cycle is repeated 4 times.

[0047] S4. Mix 1.5g of the Zn-C mixture with 7mL of organic solvent (NMP) and stir at 60℃ for 2h (to fully dissolve PVDF) to obtain a slurry;

[0048] S5. The slurry is coated onto a template (glass plate) and dried under vacuum at 60°C for 3 hours (to allow NMP to fully evaporate). The material is then peeled off, cut, and a circular zinc alloy negative electrode material with a diameter of 15 cm (thickness: 91 μm) is obtained.

[0049] See Figure 1 The obtained zinc alloy anode material (before cutting) is uniformly black, indicating that the composition of the zinc alloy anode material is uniformly distributed.

[0050] The obtained zinc alloy anode material was assembled into a coin cell (Zn-C||Zn-C), and the result was tested at a current density of 1 mA / cm². -2 Cyclic testing was conducted under the specified conditions.

[0051] Example 2

[0052] Example 1 is repeated, except that in S1, the proportion of alloying components in the alloying melt is 20 wt%; in the alloying melt, the content of aluminum is 0.5%, the content of indium is 8%, the content of bismuth is 8%, the content of tin is 3%, the content of cerium is 0.05%, the content of samarium is 0.05%, the content of ytterbium is 0.05%, the content of copper is 0.05%, the content of titanium is 0.05%, the content of magnesium is 0.05%, the content of gallium is 0.05%, the content of graphene is 0.05%, the content of carbon nanotubes is 0.05%, and the content of yttrium oxide is 0.05%.

[0053] Example 3

[0054] Example 1 is repeated, except that in S1, the alloying component accounts for 40 wt% of the alloying melt; the alloying melt contains 0.5% aluminum, 18% indium, 13% bismuth, 8% tin, 0.05% cerium, 0.05% samarium, 0.05% ytterbium, 0.05% copper, 0.05% titanium, 0.05% magnesium, 0.05% gallium, 0.05% graphene, 0.05% carbon nanotubes, and 0.05% yttrium oxide.

[0055] Comparative Example 1

[0056] Repeat Example 1, except that: S1-S2 are omitted; in S3, 800-mesh pure zinc powder (purity of 99.9%) is used instead of zinc alloy powder.

[0057] Comparative Example 2

[0058] Repeat Example 1, except that: S1-S2 are omitted; in S3, pure zinc foil (99.9% purity) with a thickness of 0.15 mm and a diameter of φ12 mm is used instead of zinc alloy powder.

[0059] Table 1. Cyclic performance test results of coin cell symmetric batteries in various embodiments and comparative examples.

[0060] Group Cycle time (h) Number of cycles (times) Example 1 1800 900 Example 2 4000 2000 Example 3 2000 1000 Comparative Example 1 80 40 Comparative Example 2 800 400

[0061] Combining the data in Table 1 and Figures 1-5 It is evident that alloying zinc before constructing the zinc anode material effectively improves the cycle performance of the assembled battery. This is likely because zinc alloying reduces excess zinc, which strongly suppresses side reactions and hydrogen evolution during charging and discharging. Simultaneously, it constructs a more stable anode framework; during electrochemical reactions, the repeated extraction and insertion of zinc ions prevents the anode structure from collapsing, thus improving cycle performance and extending battery life. Furthermore, data from Table 1 shows that by controlling the addition of indium, bismuth, and tin, and maintaining the alloying component proportion in the alloy melt at approximately 20 wt%, the battery assembled from the resulting zinc alloy anode material exhibits particularly outstanding cycle performance, achieving a cycle time of 4000 hours while the voltage remains within the ideal range. The possible reason is that the addition of appropriate amounts of elements such as bismuth, indium, and tin can accelerate the deposition kinetics of zinc ions in the zinc anode and induce uniform deposition of zinc ions, thereby controlling the nucleation process of zinc ions in the anode to be instantaneous nucleation, and alleviating problems such as dendrite growth and corrosion of zinc alloy anode materials during deposition and cycling.

[0062] The zinc alloy anode materials obtained in Examples 1-3 were used to assemble zinc-vanadium full cells for comparative testing. Specifically, NH4V4O... 10 (NVO), conductive Super P, and PVDF (AKEMAHSV900) are mixed with N-methylpyrrolidone solvent at a mass ratio of 7:2:1 to form a positive electrode material mixture; then, the positive electrode material mixture is coated onto the surface of a steel mesh (controlling the active material mass loading to approximately 1.0 mg·cm³). -2 The sample was placed in a vacuum oven and dried at 80°C for 12 hours for later use; the electrolyte was a 2 mol / L zinc sulfate solution. The test results are as follows: Figure 6 As shown, the zinc alloy anode material of Example 1 is used to assemble a zinc-vanadium full cell (corresponding to...). Figure 6 The "zinc alloy powder 10%" curve shows a cycle count of 1280 times and a capacity retention of 61.24%; the zinc alloy anode material of Example 2 assembled into a zinc-vanadium full cell (corresponding to...) Figure 6 The "20% zinc alloy powder" curve shows a cycle count of 1500 times and a capacity retention rate of 79.79%; the zinc alloy anode material of Example 3 was used to assemble a zinc-vanadium full battery (corresponding to...). Figure 6The "40% zinc alloy powder" curve shows that the number of cycles reaches 1500, and the capacity retention rate reaches 65.15%. This also shows that when the proportion of alloying components in the zinc alloy is about 20%, the cycle performance of the assembled zinc-vanadium full battery is particularly outstanding.

[0063] Comparative Example 3

[0064] Repeat Example 1, except that in S3, the zinc alloy powder is mixed with graphene and organic binder (PVDF) in a volume ratio of 4:2:2.

[0065] As a result, the obtained Zn-C mixture exhibited significant agglomeration and uneven mixing, affecting subsequent use. A possible reason is that the ratio of graphene to organic binder was too high, causing the graphene and organic binder to easily clump together and fail to mix evenly with the zinc powder, resulting in an unsatisfactory mixing effect.

[0066] The above embodiments should be understood as being used only to illustrate the present invention more clearly, and not to limit the scope of the present invention. After reading the present invention, any modifications of the present invention in various equivalent forms by those skilled in the art fall within the scope defined by the appended claims.

Claims

1. A method for preparing a zinc alloy negative electrode material, characterized in that, Includes the following steps: S1. Provide alloying melt; The alloyed melt is composed of zinc and alloying components; the alloying components account for 10-40 wt% of the alloyed melt, and the alloying components consist of aluminum, indium, bismuth, tin, RE, copper, titanium, magnesium, gallium, graphene, carbon nanotubes, and yttrium oxide; in the alloyed melt, the aluminum content is 0.3-0.7 wt%, the indium content is 1-20 wt%, the bismuth content is 3-15 wt%, the tin content is 0.5-9 wt%, and the RE content is 0.0 wt%. 9-0.21 wt%, copper content is 0.03-0.07 wt%, titanium content is 0.03-0.07 wt%, magnesium content is 0.03-0.07 wt%, gallium content is 0.03-0.07 wt%, graphene content is 0.03-0.07 wt%, carbon nanotube content is 0.03-0.07 wt%, yttrium oxide content is 0.03-0.07 wt%; RE is selected from one or more of cerium, samarium, and ytterbium; S2. After the alloyed melt is cast into a shape, it is crushed, ball-milled, and sieved to obtain zinc alloy powder. S3. The zinc alloy powder is mixed with graphene and organic binder in a volume ratio of 6-9:1-2:1-2, and ball-milled to obtain a Zn-C mixture. Among them, the proportion of zinc alloy powder in the Zn-C mixture is ≥60 vol%, and the total proportion of graphene and organic binder in the Zn-C mixture is ≤40 vol%. S4. Mix the Zn-C mixture with an organic solvent until homogeneous to obtain a slurry; S5. The slurry is coated onto a template, dried, and then cut to obtain a zinc alloy negative electrode material.

2. The preparation method according to claim 1, characterized in that, In S1, the proportion of alloying components in the alloyed melt is 15-30 wt%.

3. The preparation method according to claim 2, characterized in that, In S1, the proportion of alloying components in the alloyed melt is 18-25 wt%.

4. The preparation method according to claim 2, characterized in that, The temperature of the alloying melt is 580-650℃.

5. The preparation method according to claim 1, characterized in that, In S1, the alloyed melt contains 0.4-0.6 wt% aluminum, 2-19 wt% indium, 4-14 wt% bismuth, 0.8-8.5 wt% tin, 0.12-0.18 wt% RE, 0.04-0.06 wt% copper, 0.04-0.06 wt% titanium, 0.04-0.06 wt% magnesium, 0.04-0.06 wt% gallium, 0.04-0.06 wt% graphene, 0.04-0.06 wt% carbon nanotubes, and 0.04-0.06 wt% yttrium oxide. The RE is composed of cerium, samarium, and ytterbium, with a mass ratio of cerium, samarium, and ytterbium of 1-2:1-2:1-2.

6. The preparation method according to any one of claims 1-5, characterized in that, In S2, the particle size of the zinc alloy powder is ≤30μm.

7. The preparation method according to any one of claims 1-5, characterized in that, In S3, an all-around planetary ball mill is used for ball milling. The rotational speed of the ball mill jar is controlled at 350-450 rpm, and the rotational speed of the ball mill jar is controlled at 10-20 rpm. The ball milling is stopped for 1-3 minutes every 4-6 minutes, and the cycle is repeated 3-5 times.

8. The preparation method according to any one of claims 1-5, characterized in that, In S3, the volume ratio of the zinc alloy powder to graphene and organic binder is 7-8:1-2:1-2.

9. The preparation method according to claim 8, characterized in that, The organic binder is PVDF.

10. The preparation method according to any one of claims 1-5, characterized in that, In S4, the mass-volume ratio of Zn-C mixture to organic solvent is 1-2 g: 5-10 mL.

11. The preparation method according to claim 10, characterized in that, The organic solvent is NMP.

12. The preparation method according to claim 10, characterized in that, The Zn-C mixture is mixed with an organic solvent and stirred at 50-70°C for 10-18 hours to obtain a slurry.

13. The preparation method according to any one of claims 1-5, characterized in that, In S5, the thickness of the zinc alloy anode material is 60-120 μm.

14. The preparation method according to claim 13, characterized in that, The template is a glass plate.

15. The preparation method according to any one of claims 1-5, characterized in that, In S5, vacuum dry at 50-70℃ for 2-4 hours.

16. A zinc-ion battery, characterized in that, This includes zinc alloy anode materials prepared by the preparation method according to any one of claims 1-15.

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