Preparation method of petal-shaped magnesium ion-doped ammonium vanadate positive electrode material
By magnesium ion doping and morphology control, a petal-shaped ammonium vanadate positive electrode material was prepared, which solved the irreversible deamination problem of ammonium vanadate in aqueous zinc ion batteries and achieved efficient electrochemical performance and stable electrode cycle performance.
Patent Information
- Application Number
- CN202310330680.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-03-30
- Publication Date
- 2025-10-03
- Estimated Expiration
- 2043-03-30
AI Technical Summary
Ammonium vanadate positive electrode materials experience irreversible deamination in aqueous zinc-ion batteries, leading to structural collapse and poor cycle performance, making it difficult to meet commercial needs.
The petal-shaped ammonium vanadate positive electrode material was prepared by magnesium ion doping. Magnesium ions were introduced into ammonium vanadate through a hydrothermal reaction to expand the interlayer spacing and form stronger chemical bonds, inhibiting the irreversible deamination phenomenon. The contact area between the electrode and the electrolyte was increased through the 3D petal-shaped morphology.
The zinc ion diffusion and transport sites are improved, the cycle stability and current tolerance of the electrode are enhanced, and it has excellent rate performance and high discharge specific capacity. The capacity retention rate is as high as 90.2% after 5000 cycles.
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Figure CN116177600B_ABST
Abstract
Description
Technical Field
[0001] The invention relates to an aqueous zinc ion battery positive electrode material, and in particular to a method for preparing a petal-shaped magnesium ion-doped ammonium vanadate positive electrode material. Background Art
[0002] The scarce lithium resources in the Earth's crust, the potential safety risks of organic electrolytes and the high production costs of commercial lithium-ion batteries have led researchers to never stop seeking to develop a safe, efficient and clean alternative solution.
[0003] Among them, aqueous zinc-ion batteries are considered to be one of the most promising candidate materials. Aqueous zinc-ion batteries have the following advantages: (1) low redox potential (-0.763 V, compared to standard hydrogen electrode). (2) high theoretical capacity (819 mAh g -1 , 5851mAh ml -1 (3) The content of metallic zinc in the earth's crust is high, it is stable in the air, and the production cost is low. (4) Compared with organic electrolytes, aqueous electrolytes are non-flammable, have low safety risks, and are clean and environmentally friendly.
[0004] At present, there are many kinds of positive electrode materials for aqueous zinc-ion batteries, including Prussian blue analogues, manganese-based materials, vanadium-based materials, etc. Although Prussian blue analogues have a stable crystal structure, their low energy density makes it difficult to meet commercial needs. Manganese-based materials are limited by the Jan-Taylor effect, and phase change and manganese dissolution occur during the cycle, resulting in poor conductivity and cycle life. Compared with positive electrode materials such as manganese-based and Prussian blue analogues, vanadium-based materials have become one of the most promising electrode materials in aqueous zinc-ion battery positive electrode materials due to their flexible and diverse open skeleton structure. Among them, ammonium vanadate NH4V4O 10 It has attracted widespread attention due to its large interlayer spacing and theoretical specific capacity. However, during the cycle, ammonium vanadate materials experience irreversible deamination, which can easily cause structural collapse and lead to poor cycle performance, restricting its application in aqueous zinc-ion battery systems. Summary of the Invention
[0005] The purpose of the present invention is to provide a method for preparing a petal-shaped magnesium ion-doped ammonium vanadate positive electrode material in response to the current irreversible deamination phenomenon of ammonium vanadate.
[0006] To achieve the above object, the technical solution of the present invention includes the following steps:
[0007] Step (1): Weigh ammonium metavanadate and dissolve it in deionized water. Stir the solution magnetically in a water bath until it is fully dissolved to obtain solution A. Slowly add oxalic acid dihydrate to solution A. After the reaction is completed, adjust the pH value of solution A and continue to stir the solution fully to obtain solution B.
[0008] Step (2): adding a magnesium source to solution B, continuing to stir and dissolve thoroughly to obtain a uniform solution C; transferring solution C to a polytetrafluoroethylene high-pressure reactor, and then placing the reactor in a forced air drying oven for hydrothermal reaction.
[0009] Step (3): After the reaction is completed, the reactor is taken out and naturally cooled to room temperature, the reaction liquid is centrifuged to obtain a solid product, the product is washed and dried to obtain the final product, magnesium ion-doped ammonium vanadate material, wherein the magnesium ion-doped ammonium vanadate material is composed of nano-bars and presents a 3D petal-like morphology.
[0010] As a preferred embodiment of the present invention, in step (1), the volume of deionized water and the amount of ammonium metavanadate used are in the ratio of 80 ml to 0.64 g, and the water bath temperature is 60°C; the pH value of solution A is adjusted to 1.6 using an inorganic acid including dilute hydrochloric acid and dilute acetic acid.
[0011] As a preferred embodiment of the present invention, in step (1), the speed of magnetic stirring is 500 r / min and the stirring time is 60 min.
[0012] As a preferred embodiment of the present invention, in step (1), the mass ratio of ammonium metavanadate to oxalic acid dihydrate is 0.55:1.
[0013] As a preferred embodiment of the present invention, in step (2), the magnesium source is magnesium carbonate, basic magnesium carbonate or magnesium acetate, preferably magnesium carbonate, and the mass ratio of the magnesium source to ammonium metavanadate is 0.05:1.
[0014] As a preferred embodiment of the present invention, in step (2), the hydrothermal reaction temperature is 180° C. and the reaction time is 3 h.
[0015] As a preferred embodiment of the present invention, in step (3), the centrifugal speed is 10000 r / min.
[0016] As a preferred embodiment of the present invention, in step (3), the washing operation is to wash the solid product three times with distilled water and anhydrous ethanol respectively.
[0017] As a preferred embodiment of the present invention, in step (3), the drying process is to place the product in a vacuum drying oven at 60° C. and dry it for 24 hours.
[0018] Description of the invention principle:
[0019] The present invention uses magnesium ions to dope ammonium vanadate material. The magnesium ions enter the interlayer to replace some ammonium ions, thereby expanding the interlayer spacing, increasing the diffusion and transmission sites of zinc ions, and improving the discharge specific capacity. At the same time, stronger chemical bonds allow the magnesium ions to act as pillar ions in the interlayer, effectively inhibiting the irreversible deamination phenomenon of the ammonium vanadate material, and enhancing the electrode cycle stability and current tolerance. In addition, the 3D petal-shaped micromorphology effectively increases the contact area between the electrode and the electrolyte, further improving the electrode rate performance.
[0020] Compared with the prior art, the present invention has the following beneficial effects:
[0021] 1. The preparation process of the present invention is simple and only requires one step of hydrothermal treatment, which is low in cost and has obvious economic benefits.
[0022] 2. The reactant ratio and hydrothermal synthesis conditions of the present invention enable the obtained product to obtain a 3D petal-shaped microstructure. Compared with the common strip-shaped ammonium vanadate material, it has a larger specific surface area, increases the contact area between the electrode and the electrolyte, and obtains excellent rate capability.
[0023] 3. The magnesium ion-doped ammonium vanadate material prepared by the present invention has The large interlayer spacing effectively improves the discharge capacity. The magnesium ions form a stronger chemical bond with the vanadium oxide layer, acting as a pillar between the layers and effectively inhibiting the irreversible deamination of ammonium vanadate. -1 The discharge capacity is as high as 410 mAh g -1 , at 25Ag -1 Even at the ultra-high current density, it still has 118mAh g -1 The discharge capacity at 10A g -1 After 5000 cycles at the same current density, the capacity retention rate is as high as 90.2%.
[0024] 4. The present invention innovatively completes morphology control and metal ion doping modification in one step. The resulting material has excellent electrochemical properties and practical application value. BRIEF DESCRIPTION OF THE DRAWINGS
[0025] Figure 1 is the X-ray diffraction pattern of the petal-shaped magnesium ion-doped ammonium vanadate prepared in Example 1;
[0026] Figure 2 is a scanning electron microscope image of the petal-shaped magnesium ion-doped ammonium vanadate prepared in Example 1;
[0027] Figure 3 1 is a rate performance diagram of the petal-shaped magnesium ion-doped ammonium vanadate positive electrode material prepared in Example 1 at different current densities;
[0028] Figure 4 The petal-shaped magnesium ion-doped ammonium vanadate positive electrode material prepared in Example 1 is 10A g -1 Cycle performance diagram;
[0029] Figure 5 2 is a rate performance diagram of the petal-shaped magnesium ion-doped ammonium vanadate positive electrode material prepared in Example 2 at different current densities;
[0030] Figure 6 3 is a rate performance diagram of the petal-shaped magnesium ion-doped ammonium vanadate positive electrode material prepared in Example 3 at different current densities;
[0031] Figure 7 1 is a rate performance diagram of the petal-shaped magnesium ion-doped ammonium vanadate positive electrode material prepared in Example 4 at different current densities;
[0032] Figure 8 1 is a rate performance diagram of the petal-shaped magnesium ion-doped ammonium vanadate positive electrode material prepared in Example 5 at different current densities;
[0033] Figure 9 This is a rate performance diagram of the ammonium vanadate positive electrode material prepared in Comparative Example 1 at different current densities. DETAILED DESCRIPTION
[0034] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments. The following embodiments are intended to facilitate understanding by those skilled in the art and are not intended to further limit the present invention.
[0035] Example 1
[0036] 0.64 g of ammonium metavanadate was added to 80 ml of deionized water and heated in a 60°C waterbath with stirring until the ammonium metavanadate was completely dissolved, yielding an ammonium metavanadate solution. 1.16 g of oxalic acid dihydrate was gradually added to the ammonium metavanadate solution and magnetically stirred at 500 rpm for 60 minutes to obtain a homogeneous mixed solution with a pH of approximately 2.5. Dilute hydrochloric acid was added dropwise until the pH reached 1.6. 32 mg of magnesium carbonate was added to the mixed solution and magnetic stirring was continued for 30 minutes. The homogeneous solution was then transferred to a polytetrafluoroethylene autoclave and placed in a forced air drying oven for 3 hours at 180°C. After the autoclave cooled to room temperature, the reaction solution was poured into a centrifuge tube and centrifuged five times at 10,000 rpm. The resulting solid product was washed three times with distilled water and three times with anhydrous ethanol, then dried in a vacuum drying oven at 60°C for 24 hours. The final product was designated MNVO-1.
[0037] Example 2
[0038] 0.64 g of ammonium metavanadate was added to 80 ml of deionized water and heated in a 60°C waterbath with stirring until the ammonium metavanadate was completely dissolved, yielding an ammonium metavanadate solution. 1.16 g of oxalic acid dihydrate was gradually added to the ammonium metavanadate solution and magnetically stirred at 500 rpm for 60 minutes to obtain a homogeneous mixed solution with a pH of approximately 2.5. Dilute hydrochloric acid was added dropwise until the pH reached 1.6. 16 mg of magnesium carbonate was added to the mixed solution and magnetic stirring was continued for 30 minutes. The homogeneous solution was then transferred to a polytetrafluoroethylene autoclave and placed in a forced air drying oven for 3 hours at 180°C. After the autoclave cooled to room temperature, the reaction solution was poured into a centrifuge tube and centrifuged five times at 10,000 rpm. The resulting solid product was washed three times with distilled water and three times with anhydrous ethanol, then dried in a vacuum drying oven at 60°C for 24 hours. The final product was designated MNVO-2.
[0039] Example 3
[0040] 0.64g of ammonium metavanadate was added to 80ml of deionized water and heated in a 60°C waterbath with stirring until the ammonium metavanadate was completely dissolved, yielding an ammonium metavanadate solution. 1.16g of oxalic acid dihydrate was gradually added to the ammonium metavanadate solution and magnetically stirred at 500 rpm for 60 minutes to obtain a homogeneous mixed solution with a pH of approximately 2.5. Dilute hydrochloric acid was added dropwise until the pH reached 1.6. 48mg of magnesium carbonate was added to the mixed solution and magnetic stirring was continued for 30 minutes. The homogeneous solution was then transferred to a polytetrafluoroethylene autoclave and placed in a forced air drying oven for 3 hours at 180°C. After the autoclave cooled to room temperature, the reaction solution was poured into a centrifuge tube and centrifuged five times at 10,000 rpm. The resulting solid product was washed three times with distilled water and three times with anhydrous ethanol, then dried in a vacuum drying oven at 60°C for 24 hours. The final product was designated MNVO-3.
[0041] Example 4
[0042] 0.64 g of ammonium metavanadate was added to 80 ml of deionized water and heated in a 60°C waterbath with stirring until the ammonium metavanadate was completely dissolved, yielding an ammonium metavanadate solution. 1.16 g of oxalic acid dihydrate was gradually added to the ammonium metavanadate solution and magnetically stirred at 500 rpm for 60 minutes to obtain a homogeneous mixed solution with a pH of approximately 2.5. Dilute hydrochloric acid was then added dropwise until the pH reached 1.6. 32 mg of magnesium carbonate was added to the mixed solution and magnetic stirring was continued for 30 minutes. The homogeneous solution was then transferred to a polytetrafluoroethylene autoclave and placed in a forced air drying oven at 180°C for 6 hours. After cooling the autoclave to room temperature, the reaction solution was poured into a centrifuge tube and centrifuged five times at 10,000 rpm. The resulting solid product was washed three times with distilled water and three times with anhydrous ethanol, then dried in a vacuum drying oven at 60°C for 24 hours. The final product was designated MNVO-4.
[0043] Example 5
[0044] 0.64g of ammonium metavanadate was added to 80ml of deionized water and heated in a 60°C waterbath with stirring until the ammonium metavanadate was completely dissolved, yielding an ammonium metavanadate solution. 1.16g of oxalic acid dihydrate was gradually added to the ammonium metavanadate solution and magnetically stirred at 500 rpm for 60 minutes to obtain a homogeneous mixed solution with a pH of approximately 2.5. Dilute hydrochloric acid was added dropwise until the pH reached 1.6. 32mg of magnesium carbonate was added to the mixed solution and magnetic stirring was continued for 30 minutes. The homogeneous solution was then transferred to a polytetrafluoroethylene autoclave and placed in a forced air drying oven for 3 hours at 160°C. After the autoclave cooled to room temperature, the reaction solution was poured into a centrifuge tube and centrifuged five times at 10,000 rpm. The resulting solid product was washed three times with distilled water and three times with anhydrous ethanol, then dried in a vacuum drying oven at 60°C for 24 hours. The final product was designated MNVO-4.
[0045] Comparative Example 1
[0046] Add 0.64g of ammonium metavanadate to 80ml of deionized water and heat in a 60°C waterbath with stirring until the ammonium metavanadate is completely dissolved, yielding an ammonium metavanadate solution. Gradually add 1.16g of oxalic acid dihydrate to the ammonium metavanadate solution and magnetically stir at 500 rpm for 60 minutes to obtain a homogeneous mixed solution with a pH of approximately 2.5. Add dilute hydrochloric acid dropwise until the pH reaches 1.6. Transfer the homogeneous solution to a polytetrafluoroethylene autoclave, place the autoclave in a forced-air drying oven, and incubate at 180°C for 3 hours. After cooling the autoclave to room temperature, pour the reaction solution into a centrifuge tube and centrifuge it five times at 10,000 rpm. Wash the resulting solid product three times with distilled water and three times with anhydrous ethanol, then transfer the resulting product to a vacuum drying oven and dry it at 60°C for 24 hours. The final product is designated NVO.
[0047] The preparation method of aqueous zinc ion battery is as follows:
[0048] After mixing and grinding the products prepared in all examples, acetylene black, and polyvinylidene fluoride in a mass ratio of 7:2:1, N-methyl-2-pyrrolidone and polyvinylidene fluoride were diluted in a mass ratio of 1:24 to form a mixed slurry. The stirred slurry was evenly coated on a carbon paper punched into a diameter of 12 mm, and then transferred to a vacuum drying oven and dried at 60°C for 24 hours. The resulting positive electrode sheet had an active material loading of 1.6 mg / cm 2 The aqueous zinc ion button cell was composed of zinc foil as the negative electrode, glass fiber as the separator, and 3 mol / L zinc trifluoromethanesulfonate as the electrolyte. The electrochemical performance of the aqueous zinc ion battery was tested with a test voltage range of 0.4-1.5 V and a current density of 0.1-25 Ag. -1 .
[0049] Implementation Effect
[0050] Figure 1 This is the X-ray diffraction pattern of the petal-shaped magnesium ion-doped ammonium vanadate prepared in Example 1. Its X-ray diffraction pattern is basically consistent with the ammonium vanadate standard card. Magnesium ion doping does not change the crystal structure of ammonium vanadate, and its (001) peak shifts to a low angle, indicating that after magnesium ion doping, the interlayer spacing is expanded.
[0051] Figure 2 This is a scanning electron microscope image of the petal-shaped magnesium ion-doped ammonium vanadate prepared in Example 1. It can be seen that the prepared material as a whole presents a uniformly distributed petal-shaped microscopic morphology.
[0052] Figure 3 This is the rate performance diagram of the petal-shaped magnesium ion-doped ammonium vanadate positive electrode material prepared in Example 1 at different current densities. -1The current density is 410 mAh g -1 Discharge specific capacity, at 25A g -1 Even at the ultra-high current density, it still has 118mAh g -1 Discharge specific capacity.
[0053] Figure 4 The petal-shaped magnesium ion-doped ammonium vanadate positive electrode material prepared in Example 1 is 10A g -1 Cycling performance diagram. After 5000 long cycles, there is still a capacity retention rate of 90.2%.
[0054] Figure 5-8 This is a graph showing the rate performance of the petal-shaped magnesium ion-doped ammonium vanadate cathode material prepared in Examples 2-5 at different current densities. Figure 9 From the rate performance in the comparative example, it can be seen that the non-preferred petal-shaped magnesium ion-doped ammonium vanadate positive electrode material prepared by the present invention still has more superior electrochemical performance.
Claims
1. A method for preparing a petal-shaped magnesium ion-doped ammonium vanadate positive electrode material, characterized in that: The following steps are involved: Step (1): Weigh ammonium metavanadate and dissolve it in deionized water. Stir the solution magnetically in a water bath until it is fully dissolved to obtain solution A. Slowly add oxalic acid dihydrate to solution A. After the reaction is completed, adjust the pH value of solution A and continue to stir the solution fully to obtain solution B. The mass ratio of ammonium metavanadate to oxalic acid dihydrate is 0.55:
1. Step (2): adding a magnesium source to solution B and continuing to stir and dissolve thoroughly to obtain a uniform solution C; Transferring solution C to a polytetrafluoroethylene autoclave, and then placing the autoclave in a forced air drying oven for hydrothermal reaction; the magnesium source is magnesium carbonate, basic magnesium carbonate or magnesium acetate, and the mass ratio of the magnesium source to ammonium metavanadate is 0.05:1; Step (3): After the reaction is completed, the reactor is taken out and naturally cooled to room temperature, the reaction liquid is centrifuged to obtain a solid product, and the product is washed and dried to obtain the final product, magnesium ion-doped ammonium vanadate material.
2. The method for preparing a petal-shaped magnesium ion-doped ammonium vanadate positive electrode material according to claim 1, wherein: The magnesium ion-doped ammonium vanadate cathode material is composed of nanorods and exhibits a 3D petal-like morphology.
3. The method for preparing a petal-shaped magnesium ion-doped ammonium vanadate positive electrode material according to claim 1, wherein: In step (1), the volume of deionized water and the amount of ammonium metavanadate used are in the ratio of 80 ml to 0.64 g, and the water bath temperature is 60° C. The pH value of solution A is adjusted to 1.6 using inorganic acids including dilute hydrochloric acid and dilute acetic acid.
4. The method for preparing a petal-shaped magnesium ion-doped ammonium vanadate positive electrode material according to claim 1, wherein: In step (1), the speed of magnetic stirring is 500 r / min and the stirring time is 60 min.
5. The method for preparing a petal-shaped magnesium ion-doped ammonium vanadate positive electrode material according to claim 1, wherein: The magnesium source is magnesium carbonate.
6. The method for preparing a petal-shaped magnesium ion-doped ammonium vanadate positive electrode material according to claim 1, wherein: In step (2), the hydrothermal reaction temperature is 180° C. and the reaction time is 3 h.
7. The method for preparing a petal-shaped magnesium ion-doped ammonium vanadate positive electrode material according to claim 1, wherein: In step (3), the centrifugal speed is 10000 r / min, and the washing operation is to wash the solid product with distilled water and alcohol three times respectively.
8. The method for preparing a petal-shaped magnesium ion-doped ammonium vanadate positive electrode material according to claim 1, wherein: In step (3), the drying process is to place the product in a vacuum drying oven at 60°C for 24 hours.