Positive electrode material V2O3 / C of rechargeable aqueous zinc ion battery, electrode plate of positive electrode material V2O3 / C and preparation method of positive electrode material V2O3 / C

Abstract

The invention belongs to the field of electrochemistry, and discloses a positive electrode material V2O3 / C of a rechargeable aqueous zinc ion battery, an electrode plate of the positive electrode material V2O3 / C and a preparation method of the positive electrode material V2O3 / C. A carbon-coated vanadium trioxide nano material is obtained by adopting hydrothermal synthesis and calcination and is applied to a positive electrode of the rechargeable aqueous zinc ion battery. The material is simple and convenient to synthesize and low in cost, and shows relatively high specific capacity and excellent rate capability and cycling stability when being used as a zinc ion battery positive electrode material, so that the selection of water system energy storage battery materials is more diversified.

Description

Technical Field

[0001] The present invention belongs to the field of electrochemistry and relates to a positive electrode material for an aqueous zinc ion battery, in particular to a positive electrode material V2O3 / C for a rechargeable aqueous zinc ion battery and an electrode sheet and a preparation method thereof. Background Art

[0002] With the surge in global energy demand and environmental pressure, the research and development of new energy materials is urgent. Although lithium-ion batteries dominate the energy storage market, problems such as resource scarcity, safety hazards, and high costs have become prominent, which has promoted the exploration of various types of aqueous multivalent ion batteries. Among them, rechargeable zinc-ion batteries (ZIBs) have become a strong candidate for the next generation of energy storage technology due to their significant advantages. Zinc is abundant, inexpensive, and environmentally friendly, solving the problem of lithium resource scarcity. The use of aqueous electrolytes completely eliminates the risks of flammability and explosion of organic electrolytes, ensuring the safety of large-scale applications.

[0003] However, ZIBs still face many technical challenges. In terms of positive electrode materials, commonly used materials such as manganese-based and vanadium-based materials have the problems of rapid specific capacity decay and poor cycle stability. Vanadium exists in multiple valence states (+2 to +5). During the charge and discharge process, vanadium ions can undergo reversible redox reactions, allowing more ions to be embedded and extracted, thereby increasing the battery capacity. Taking V2O3 as an example, the vanadium atoms in the crystal are connected by 3D VV bonds, and the oxygen atoms form a deformed octahedron. This structure allows the 3d orbital electrons of vanadium to be transferred along the VV bonds, giving it high conductivity, facilitating electron transport, and providing good kinetic conditions for ion embedding.

[0004] However, pure V2O3 materials have some significant problems in practical applications. For example, their poor electrical conductivity leads to poor charge transfer within the battery, affecting the battery's charge and discharge performance. The low valence of vanadium in V2O3 makes it unstable in air and easily oxidized. During the charge and discharge process, the structure of V2O3 is prone to irreversible changes, resulting in severe battery capacity decay and poor cycle stability. These problems have severely limited the widespread application of pure V2O3 as a cathode material in aqueous zinc-ion batteries.

[0005] To improve the performance of V2O3 cathode materials, researchers have tried various approaches, such as nanostructure design and element doping. However, these methods still have limitations in improving the conductivity and structural stability of the materials. They cannot fundamentally address the problems of pure V2O3 materials and fail to meet the urgent demand for high-performance cathode materials in aqueous zinc-ion batteries. Therefore, the development of a new and effective method for preparing V2O3-based cathode materials is of great practical significance. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention has developed a novel, high-performance cathode material for aqueous zinc-ion batteries. Specifically, the material is a carbon-coated vanadium oxide composite. By combining this composite with a carbon material, the present invention effectively improves its stability while reducing agglomeration. The result is a highly dispersed carbon-coated vanadium trioxide nanocomposite material, which exhibits excellent performance as a cathode material for zinc-ion batteries.

[0007] The present invention adopts the following technical solutions:

[0008] A method for preparing V2O3 / C, a positive electrode material for aqueous zinc ion batteries, wherein the main preparation process is as follows:

[0009] (1) Weigh ammonium metavanadate and glucose, add deionized water, and stir evenly;

[0010] (2) Transfer the resulting solution to a hydrothermal reactor and react at 180-200°C for 10-14 hours;

[0011] (3) After the hydrothermal reactor is cooled to room temperature, the obtained product is washed and the black precipitate is collected;

[0012] (4) transferring the product to a vacuum drying oven and drying the product;

[0013] (5) The product is calcined under a nitrogen atmosphere to obtain the product V2O3 / C.

[0014] Furthermore, in step (1), the mass ratio of ammonium metavanadate to glucose is 1 to 3:1.

[0015] Furthermore, in step (3), the washing is performed with deionized water and ethanol for 3 to 6 times respectively.

[0016] Furthermore, in step (3), the black precipitate is collected by centrifugation at 2800-3200 rpm.

[0017] Furthermore, the drying temperature in step (4) is 50-70° C., and the drying time is 10-24 h.

[0018] Furthermore, the calcination temperature in step (5) is 600-800° C., and the calcination time is 2-4 hours.

[0019] A method for coating an electrode sheet using V2O3 / C as a positive electrode material for aqueous zinc ion batteries. The preparation process of the electrode sheet is as follows:

[0020] The product V2O3 / C, acetylene black, and polyvinylidene fluoride (PVDF) were dissolved in N-methylpyrrolidone (NMP) at a ratio of 7:2:1 and stirred in a beaker for 10-12 hours to prepare a slurry. The slurry was evenly coated on a titanium sheet, transferred to a vacuum drying oven, and dried at 50-70°C for 8-12 hours to obtain a positive electrode sheet. After drying, the active material mass on the electrode sheet reached 1-2 mg.

[0021] The battery assembly using the positive electrode sheet of the aqueous zinc ion battery includes the following steps:

[0022] The prepared V2O3 / C material was used as the positive electrode, the zinc sheet was used as the counter electrode, and the electrolyte was 90-160 μL 3 mol·L -1 Zinc trifluoromethanesulfonate (Zn(CF3SO3)2), 2032 model half-cell with glass fiber diaphragm, at a scan rate of 5mV·s -1 The battery was tested for cyclic voltammetry in the potential range of 0.2 to 1.6 V. -1 The battery is subjected to constant current charge and discharge test.

[0023] The preparation method, materials and performance of V2O3 / C used in the present invention have the following characteristics and advantages compared with the existing technology:

[0024] (1) Compared with lithium-ion batteries, zinc-ion batteries have the advantages of low cost and safe and stable electrolyte, which provides diversity for energy storage batteries.

[0025] (2) This material is synthesized by hydrothermal and calcination methods, with low raw material cost, simple synthesis process and strong operability.

[0026] (3) In this material, V2O3 is highly dispersed in the carbon material, while the stability and dispersibility of V2O3 are improved, showing excellent electrochemical performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is the XRD pattern of V2O3 / C;

[0028] Figure 2 It is the SEM image of V2O3 / C;

[0029] Figure 3 It is the impedance diagram of V2O3 / C and V2O3;

[0030] Figure 4 It is the rate diagram of V2O3 / C;

[0031] Figure 5 It is the specific capacity-voltage diagram of V2O3 / C;

[0032] Figure 6The V2O3 / C and V2O3 at 3.0A·g -1 GCD diagram under current density;

[0033] Figure 7 The results of V2O3 / C at different scan rates (0.2~1.0mV s -1 ) under CV curve. DETAILED DESCRIPTION

[0034] Example 1

[0035] Weigh 2.34g of ammonium metavanadate and 1.98g of glucose into a small beaker. Add 35mL of deionized water to the beaker and stir for 30 minutes until the solution stabilizes. Transfer the resulting solution to a 50mL hydrothermal reactor, place it in a forced air drying oven, and react at 180°C for 12 hours. After the hydrothermal reactor cools to room temperature, wash the resulting product with deionized water and ethanol 3-6 times, respectively, and collect the black precipitate by centrifugation at 2800rpm. Transfer the product to a vacuum drying oven and dry it at 50°C for 12 hours to obtain the product. Transfer the product to a tube furnace and calcine at 700°C for 2 hours under a nitrogen atmosphere to obtain the product V2O3 / C.

[0036] V2O3 / C, acetylene black, and polyvinylidene fluoride (PVDF) were dissolved in N-methylpyrrolidone (NMP) at a ratio of 7:2:1. The mixture was stirred in a beaker for 12 hours to prepare a slurry. The slurry was evenly coated on a titanium sheet and transferred to a vacuum drying oven. The sheet was dried at 55°C for 12 hours to obtain a positive electrode sheet. After drying, the active material mass on the sheet reached 1-2 mg.

[0037] V2O3 / C was used as the positive electrode, zinc sheet as the counter electrode, and the electrolyte was 120 μL 3 mol·L -1 Zinc trifluoromethanesulfonate (Zn(CF3SO3)2), glass fiber separator, assembled 2032 model batteries, and performed rate testing.

[0038] Example 2

[0039] Weigh 2.34g of ammonium metavanadate and 1.98g of glucose into a small beaker. Add 35mL of deionized water to the beaker and stir for 30 minutes until the solution stabilizes. Transfer the resulting solution to a 50mL hydrothermal reactor, place it in a forced air drying oven, and react at 180°C for 12 hours. After the hydrothermal reactor cools to room temperature, wash the resulting product with deionized water and ethanol 3-6 times, respectively, and collect the black precipitate by centrifugation at 2800rpm. Transfer the product to a vacuum drying oven and dry it at 50°C for 12 hours to obtain the product. Transfer the product to a tube furnace and calcine at 700°C for 2 hours under a nitrogen atmosphere to obtain the product V2O3 / C.

[0040] V2O3 / C, acetylene black, and polyvinylidene fluoride (PVDF) were dissolved in N-methylpyrrolidone (NMP) at a ratio of 7:2:1. The mixture was stirred in a beaker for 12 hours to prepare a slurry. The slurry was evenly coated on a titanium sheet and transferred to a vacuum drying oven. The sheet was dried at 55°C for 12 hours to obtain a positive electrode sheet. After drying, the active material mass on the sheet reached 1-2 mg.

[0041] V2O3 / C was used as the positive electrode, zinc sheet as the counter electrode, and the electrolyte was 120 μL 3 mol·L -1 Zinc trifluoromethanesulfonate (Zn(CF3SO3)2), the diaphragm is a glass fiber diaphragm, and a 2032 model battery is assembled for long cycle testing.

[0042] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A method for preparing V2O3 / C as a positive electrode material for aqueous zinc ion batteries, characterized in that: The steps include: (1) Weigh ammonium metavanadate and glucose, add deionized water, and stir evenly; (2) Transfer the resulting solution to a hydrothermal reactor and react at 180-200°C for 10-14 hours; (3) After the hydrothermal reactor is cooled to room temperature, the obtained product is washed and the black precipitate is collected; (4) transferring the product to a vacuum drying oven and drying the product; (5) The product is calcined under a nitrogen atmosphere to obtain the product V2O3 / C.

2. The method for preparing V2O3 / C as a positive electrode material for aqueous zinc ion batteries according to claim 1, wherein: In step (1), the mass ratio of ammonium metavanadate to glucose is 1 to 3:

1.

3. The method for preparing V2O3 / C as a positive electrode material for aqueous zinc ion batteries according to claim 1, wherein: Step (3) washing: washing with deionized water and ethanol for 3 to 6 times respectively.

4. The method for preparing V2O3 / C as a positive electrode material for aqueous zinc ion batteries according to claim 1, wherein: Step (3) is to collect the black precipitate by centrifugation at 2800-3200 rpm.

5. The method for preparing V2O3 / C as a positive electrode material for aqueous zinc ion batteries according to claim 1, wherein: The drying temperature in step (4) is 50-70° C., and the drying time is 10-24 hours.

6. The method for preparing V2O3 / C as a positive electrode material for aqueous zinc ion batteries according to claim 1, wherein: The calcination temperature in step (5) is 600-800° C., and the calcination time is 2-4 hours.

7. A V2O3 / C cathode material for aqueous zinc ion batteries, characterized in that: Prepared according to the preparation method according to claim 1.

8. The method for coating an electrode sheet with V2O3 / C as the positive electrode material for aqueous zinc ion batteries according to claim 7, characterized in that: The product V2O3 / C, acetylene carbon black and polyvinylidene fluoride are dissolved in N-methylpyrrolidone in a ratio of 7:2:1, stirred for 10 to 12 hours to prepare a slurry, the slurry is evenly coated on a titanium sheet, and vacuum dried at 50 to 70°C for 8 to 12 hours to obtain a positive electrode sheet.

9. The V2O3 / C electrode sheet as claimed in claim 8 is used for battery assembly, characterized in that: The prepared V2O3 / C material was used as the positive electrode, the zinc sheet was used as the counter electrode, and the electrolyte was 90-160 μL 3 mol·L -1 Zinc trifluoromethanesulfonate, 2032 model half-cell with glass fiber separator.

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