Sulfur vacancy-containing nanoflower-like vanadium zinc disulfide cathode material for ion batteries and preparation method thereof

Abstract

The application discloses a kind of nanoflower-shaped vanadium zinc disulfide ion battery positive electrode materials containing sulfur vacancy and preparation method thereof, belong to energy storage technology material preparation technical field.The method disclosed in the application uses water and ethylene glycol as solvent, uses ammonium metavanadate as vanadium source, and uses thioacetamide as sulfur source, first ammonium metavanadate is dissolved in ethylene glycol, then thioacetamide and deionized water are added, after stirring and dissolving, add ammonia water to adjust pH value, then after stirring, precursor solution is transferred to stainless steel reaction kettle to carry out solvothermal reaction, the obtained product is collected, washed, vacuum dried, and then annealed to obtain a sulfur vacancy-containing vanadium disulfide product.The presence of sulfur vacancy in the sulfur vacancy-containing vanadium disulfide product further improves the electrochemical kinetics of the material for zinc ion deintercalation, thereby making the vanadium disulfide have good cycle stability and rate performance.

Description

Technical Field

[0001] This invention belongs to the field of energy storage technology material preparation technology, specifically relating to a nano-flower-like vanadium zinc disulfide ion battery cathode material containing sulfur vacancies and its preparation method. Background Technology

[0002] In recent years, the development and use of renewable energy has become an important way to solve the energy crisis. However, common renewable energy sources are scattered and random, making them difficult to collect, store, and convert. This problem can be solved by electrochemical power sources. Currently, lithium-ion batteries (LIBs) are the most widely used batteries in commercial applications. However, limited lithium resources and high production costs have hindered the development of lithium-ion batteries. Aqueous zinc-ion batteries (AZIBs) have advantages due to their low redox potential, high theoretical capacity, and high volumetric capacity (820 mAh·g). -1 and 5855mAh·cm -3 Zn is considered the most promising battery of the future due to its low price and low assembly cost. 2+ The radius is very small But due to Li + In comparison, Zn 2+ The electrostatic interaction between Zn and the crystal structure of the cathode material is stronger, making it difficult to find a suitable insertable cathode material. Generally, Zn... 2+ The surrounding H2O molecules can react with Zn 2+ They are co-inserted into the positive electrode material to buffer its high charge density, but the radius of hydrated zinc ions... The specific capacity is relatively large, thus further increasing the requirements for cathode materials. Current research on AZIB cathode materials can be divided into the following categories: manganese-based compounds, vanadium-based compounds, Prussian blue analogs, and organic compounds. Among them, vanadium-based materials have received widespread attention due to their high specific capacity. VS2, as a type of vanadium-based compound, not only possesses higher specific capacity than graphite... Much larger interlayer spacing To promote Zn 2+ Insertion / extraction, and with faster ion diffusion kinetics than vanadium oxide; due to S 2- and O 2- The difference in electronegativity makes VS2 and Zn 2+ The electrostatic interaction between them is low; this characteristic makes VS2 a promising cathode material for AZIB. However, VS2 exhibits significant volume changes during charging and discharging, and its layered stacked structure reduces ion transport kinetics, resulting in poor cycle stability and rate performance of AZIB. Summary of the Invention

[0003] In order to overcome the shortcomings of the prior art, the present invention aims to provide a nano-flower-like vanadium zinc disulfide battery cathode material containing sulfur vacancies and its preparation method, so as to solve the technical problems of poor cycle stability and rate performance of existing VS2 as cathode material.

[0004] To achieve the above objectives, the present invention employs the following technical solution:

[0005] This invention discloses a method for preparing a nano-flower-like vanadium zinc disulfide cathode material containing sulfur vacancies, comprising the following steps:

[0006] S1: A precursor solution was prepared using ammonium metavanadate, ethylene glycol, thioacetamide, deionized water, and ammonia as raw materials.

[0007] S2: The precursor solution is subjected to a hydrothermal reaction, followed by washing and drying to obtain vanadium disulfide powder;

[0008] S3: After heat treatment of vanadium disulfide powder, a nano-flower-like vanadium disulfide zinc-ion battery cathode material containing sulfur vacancies is obtained.

[0009] Further, in S1, ammonium metavanadate, ethylene glycol, thioacetamide, deionized water, and ammonia are used as raw materials to prepare a precursor solution, including the following steps:

[0010] S11: Mix ammonium metavanadate and ethylene glycol and stir at a constant temperature to obtain mixed solution A; mix mixed solution A with deionized water to obtain mixed solution B;

[0011] S22: Add thioacetamide to mixed solution B to obtain mixed solution C; adjust the pH value of mixed solution C to obtain the precursor solution.

[0012] Further, the molar ratio of thioacetamide to ammonium metavanadate is 1:(0.05-0.2); the volume ratio of deionized water to ethylene glycol is 1:(0.25-4); and the concentration of ammonium metavanadate in the mixed solution C is 0.08-0.12 mol / L.

[0013] Furthermore, the pH of the mixed solution C was adjusted to 9-11 using ammonia solution with a molar concentration of 25%-30%.

[0014] Furthermore, in S11, the constant temperature is carried out in a water bath; the constant temperature is 60°C.

[0015] Furthermore, in S2, the hydrothermal reaction is carried out under closed conditions; the temperature of the hydrothermal reaction is 150-200°C, and the time of the hydrothermal reaction is 10-24 hours.

[0016] Furthermore, in S2, the drying is performed using vacuum drying; the parameters for vacuum drying are: pressure of 0.8–1.0 MPa, drying temperature of 40–80°C, and drying time of 5–15 h.

[0017] Furthermore, in S2, the heat treatment method is annealing; the annealing is performed in nitrogen at 200–500°C for 1–4 hours.

[0018] Furthermore, the annealing process is carried out over a period of 2 to 9 hours, with a heating rate of 60 to 300 °C / h.

[0019] The present invention also discloses a nano-flower-like vanadium zinc disulfide cathode material containing sulfur vacancies prepared by the above preparation method.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] This invention discloses a method for preparing a sulfur-vacancy-containing nanoflower-like vanadium disulfide zinc-ion battery cathode material. Using water and ethylene glycol as solvents, ammonium metavanadate as the vanadium source and thioacetamide as the sulfur source, the method involves first dissolving ammonium metavanadate in ethylene glycol, then adding thioacetamide and deionized water. After stirring and dissolving, ammonia is added to adjust the pH value, yielding a precursor solution. The precursor solution undergoes a solvothermal reaction, and the resulting product is washed, dried, and then heat-treated to obtain a sulfur-vacancy-containing vanadium disulfide product with a nanoflower-like structure. This method controls the morphology of vanadium disulfide without the addition of surfactants, and prepares a sulfur-vacancy-containing nanoflower-like vanadium disulfide as a zinc-ion battery cathode material via a one-step solvothermal method. This method is simple to synthesize, easy to control, and reduces experimental costs.

[0022] This invention also discloses the application of vanadium disulfide nanoflower-like structures containing sulfur vacancies prepared by the above-described method as a cathode material for zinc-ion batteries. This nanoflower-like structure possesses a large specific surface area and a small interlamellar spacing, exhibiting a unique nanoflower microstructure and sulfur vacancy defects, providing more active sites and shortening the Zn... 2+ The diffusion distance of Zn is increased. 2+ Carrier transport efficiency; in addition, the introduction of sulfur vacancies provides more active sites, while improving structural stability, alleviating the problem of rapid capacity decay during cycling, and improving the specific capacity of the material when operating at high current, exhibiting excellent electrochemical performance; the sulfur vacancies in the sulfur-containing vanadium disulfide products further enhance the electrochemical kinetics of the material, thus giving vanadium disulfide good cycling stability and rate performance. Attached Figure Description

[0023] Figure 1The XRD pattern of the sulfur-vacancy-containing nanoflower-like vanadium zinc disulfide ion battery cathode material prepared in Example 1 is shown.

[0024] Figure 2 This is a scanning electron microscope image of the sulfur-vacancy-containing nanoflower-like vanadium zinc disulfide ion battery cathode material prepared in Example 1.

[0025] Figure 3 XPS comparison images of vanadium disulfide powder before and after annealing in Example 1;

[0026] Figure 4 This is a scanning electron microscope image of the sulfur-vacancy-containing nanoflower-like vanadium zinc disulfide ion battery cathode material prepared in Example 2;

[0027] Figure 5 This is a scanning electron microscope image of the sulfur-vacancy-containing nanoflower-like vanadium zinc disulfide ion battery cathode material prepared in Example 3;

[0028] Figure 6 This is a scanning electron microscope image of the sulfur-vacancy-containing nanoflower-like vanadium zinc disulfide ion battery cathode material prepared in Example 4.

[0029] Figure 7 This is a scanning electron microscope image of the sulfur-vacancy-containing nanoflower-like vanadium zinc disulfide ion battery cathode material prepared in Example 5.

[0030] Figure 8 This is a scanning electron microscope image of the sulfur-vacancy-containing nanoflower-like vanadium zinc disulfide ion battery cathode material prepared in Example 6.

[0031] Figure 9 This is a scanning electron microscope image of the sulfur-vacancy-containing nanoflower-like vanadium zinc disulfide ion battery cathode material prepared in Example 7. Detailed Implementation

[0032] To enable those skilled in the art to understand the features and effects of the present invention, the terms and expressions used in the specification and claims are explained and defined in general below. Unless otherwise specified, all technical and scientific terms used herein have the ordinary meaning understood by those skilled in the art regarding the present invention, and in case of conflict, the definitions in this specification shall prevail.

[0033] The theories or mechanisms described and disclosed herein, whether right or wrong, should not in any way limit the scope of the invention, that is, the contents of the invention can be implemented without being limited by any particular theory or mechanism.

[0034] In this document, all features defined by numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are for the sake of brevity and convenience only. Accordingly, descriptions of numerical ranges or percentage ranges should be considered as covering and specifically disclosing all possible sub-ranges and individual numerical values ​​(including integers and fractions) within those ranges.

[0035] In this article, unless otherwise specified, “contains,” “includes,” “containing,” “has,” or similar terms cover the meanings of “composed of” and “mainly composed of,” for example, “A contains a” covers the meanings of “A contains a and others” and “A contains only a.”

[0036] For the sake of brevity, not all possible combinations of the technical features in each implementation scheme or embodiment are described herein. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each implementation scheme or embodiment can be combined arbitrarily, and all possible combinations should be considered within the scope of this specification.

[0037] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0038] The following examples use instruments and equipment conventional in the art. Experimental methods in the following examples, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer. All raw materials used in the following examples are conventional commercially available products with specifications conventional in the art. In this specification and the following examples, unless otherwise specified, "%" refers to weight percentage, "parts" refers to parts by weight, and "ratio" refers to weight proportion.

[0039] Example 1

[0040] A method for preparing a nano-flower-like vanadium zinc disulfide cathode material containing sulfur vacancies includes the following steps:

[0041] S1: Add 0.5g of ammonium metavanadate to 20mL of ethylene glycol, and stir evenly in a water bath at a constant temperature of 60℃ to obtain an orange-yellow transparent mixed solution A; add 30mL of deionized water to mixed solution A to obtain mixed solution B;

[0042] Add 2g of thioacetamide to mixed solution B and stir until the thioacetamide is completely dissolved to obtain mixed solution C. Add 25% ammonia solution dropwise to adjust the pH of mixed solution C to 9-11. When the solution turns dark green, the precursor solution is obtained. At this time, the molar ratio of thioacetamide to ammonium metavanadate is 1:0.15, and the concentration of ammonium metavanadate in mixed solution C is about 0.1mol / L.

[0043] S2: The precursor solution was poured into a polytetrafluoroethylene-lined reactor and reacted at 160°C for 16 hours under sealed conditions. After the reaction, the reactor was cooled to room temperature, then washed and vacuum dried to obtain vanadium disulfide powder. The vacuum drying parameters were: pressure 1.0 MPa and drying temperature 75°C.

[0044] The drying time is 5 hours;

[0045] S3: The vanadium disulfide powder obtained above is heated to 300°C in nitrogen at a heating rate of 60°C / h and annealed for 2 hours. The annealing cycle is 5 hours to obtain a nano-flower-like vanadium disulfide zinc-ion battery cathode material containing sulfur vacancies.

[0046] Example 2

[0047] A method for preparing a nano-flower-like vanadium zinc disulfide cathode material containing sulfur vacancies includes the following steps:

[0048] S1: Add 0.5g of ammonium metavanadate to 30mL of ethylene glycol, and stir evenly in a water bath at a constant temperature of 60℃ to obtain an orange-yellow transparent mixed solution A; add 20mL of deionized water to mixed solution A to obtain mixed solution B;

[0049] Add 2g of thioacetamide to mixed solution B and stir until the thioacetamide is completely dissolved to obtain mixed solution C. Add 25% ammonia solution dropwise to adjust the pH of mixed solution C to 9-11. When the solution turns dark green, the precursor solution is obtained. At this time, the molar ratio of thioacetamide to ammonium metavanadate is 1:0.15, and the concentration of ammonium metavanadate in mixed solution C is approximately 0.11 mol / L.

[0050] S2: The precursor solution was poured into a polytetrafluoroethylene-lined reactor and reacted at 160°C for 16 hours under sealed conditions. After the reaction, the reactor was cooled to room temperature, then washed and vacuum dried to obtain vanadium disulfide powder. The vacuum drying parameters were: pressure 1.0 MPa and drying temperature 75°C.

[0051] The drying time is 5 hours;

[0052] S3: The vanadium disulfide powder obtained above is heated to 300°C in nitrogen at a heating rate of 60°C / h and annealed for 2 hours. The annealing cycle is 5 hours to obtain a nano-flower-like vanadium disulfide zinc-ion battery cathode material containing sulfur vacancies.

[0053] Example 3

[0054] A method for preparing a nano-flower-like vanadium zinc disulfide cathode material containing sulfur vacancies includes the following steps:

[0055] S1: Add 0.5g of ammonium metavanadate to 20mL of ethylene glycol, and stir evenly in a water bath at a constant temperature of 60℃ to obtain an orange-yellow transparent mixed solution A; add 20mL of deionized water to mixed solution A to obtain mixed solution B;

[0056] Add 2g of thioacetamide to mixed solution B and stir until the thioacetamide is completely dissolved to obtain mixed solution C. Add 25% ammonia solution dropwise to adjust the pH of mixed solution C to 9-11. When the solution turns dark green, the precursor solution is obtained. At this time, the molar ratio of thioacetamide to ammonium metavanadate is 1:0.15, and the concentration of ammonium metavanadate in mixed solution C is approximately 0.11 mol / L.

[0057] S2: The precursor solution was poured into a polytetrafluoroethylene-lined reactor and reacted at 160°C for 16 hours under sealed conditions. After the reaction, the reactor was cooled to room temperature, then washed and vacuum dried to obtain vanadium disulfide powder. The vacuum drying parameters were: pressure 1.0 MPa and drying temperature 75°C.

[0058] The drying time is 5 hours;

[0059] S3: The vanadium disulfide powder obtained above is heated to 300°C in nitrogen at a heating rate of 60°C / h and annealed for 2 hours. The annealing cycle is 5 hours to obtain a nano-flower-like vanadium disulfide zinc-ion battery cathode material containing sulfur vacancies.

[0060] Example 4

[0061] A method for preparing a nano-flower-like vanadium zinc disulfide cathode material containing sulfur vacancies includes the following steps:

[0062] S1: Add 0.5g of ammonium metavanadate to 20mL of ethylene glycol, and stir evenly in a water bath at a constant temperature of 60℃ to obtain an orange-yellow transparent mixed solution A; add 50mL of deionized water to mixed solution A to obtain mixed solution B;

[0063] Add 2g of thioacetamide to mixed solution B and stir until the thioacetamide is completely dissolved to obtain mixed solution C. Add 25% ammonia solution dropwise to adjust the pH of mixed solution C to 9-11. When the solution turns dark green, the precursor solution is obtained. At this time, the molar ratio of thioacetamide to ammonium metavanadate is 1:0.15, and the concentration of ammonium metavanadate in mixed solution C is approximately 0.08 mol / L.

[0064] S2: The precursor solution was poured into a polytetrafluoroethylene-lined reactor and reacted at 160°C for 16 hours under sealed conditions. After the reaction, the reactor was cooled to room temperature, then washed and vacuum dried to obtain vanadium disulfide powder. The vacuum drying parameters were: pressure 1.0 MPa and drying temperature 75°C.

[0065] The drying time is 5 hours;

[0066] S3: The vanadium disulfide powder obtained above is heated to 300°C in nitrogen at a heating rate of 60°C / h and annealed for 2 hours. The annealing cycle is 5 hours to obtain a nano-flower-like vanadium disulfide zinc-ion battery cathode material containing sulfur vacancies.

[0067] Example 5

[0068] A method for preparing a nano-flower-like vanadium zinc disulfide cathode material containing sulfur vacancies includes the following steps:

[0069] S1: Add 0.5g of ammonium metavanadate to 50mL of ethylene glycol, and stir evenly in a water bath at a constant temperature of 60℃ to obtain an orange-yellow transparent mixed solution A; add 30mL of deionized water to mixed solution A to obtain mixed solution B;

[0070] Add 2g of thioacetamide to mixed solution B and stir until the thioacetamide is completely dissolved to obtain mixed solution C. Add 25% ammonia solution dropwise to adjust the pH of mixed solution C to 9-11. When the solution turns dark green, the precursor solution is obtained. At this time, the molar ratio of thioacetamide to ammonium metavanadate is 1:0.15, and the concentration of ammonium metavanadate in mixed solution C is approximately 0.12 mol / L.

[0071] S2: The precursor solution was poured into a polytetrafluoroethylene-lined reactor and reacted at 160°C for 16 hours under sealed conditions. After the reaction, the reactor was cooled to room temperature, then washed and vacuum dried to obtain vanadium disulfide powder. The vacuum drying parameters were: pressure 1.0 MPa and drying temperature 75°C.

[0072] The drying time is 5 hours;

[0073] S3: The vanadium disulfide powder obtained above is heated to 300°C in nitrogen at a heating rate of 60°C / h and annealed for 2 hours. The annealing cycle is 5 hours to obtain a nano-flower-like vanadium disulfide zinc-ion battery cathode material containing sulfur vacancies.

[0074] Example 6

[0075] A method for preparing a nano-flower-like vanadium zinc disulfide cathode material containing sulfur vacancies includes the following steps:

[0076] S1: Add 0.5g of ammonium metavanadate to 20mL of ethylene glycol, and stir evenly in a water bath at a constant temperature of 60℃ to obtain an orange-yellow transparent mixed solution A; add 30mL of deionized water to mixed solution A to obtain mixed solution B;

[0077] Add 2g of thioacetamide to mixed solution B and stir until the thioacetamide is completely dissolved to obtain mixed solution C. Add 25% ammonia solution dropwise to adjust the pH of mixed solution C to 9-11. When the solution turns dark green, the precursor solution is obtained. At this time, the molar ratio of thioacetamide to ammonium metavanadate is 1:0.15, and the concentration of ammonium metavanadate in mixed solution C is about 0.1mol / L.

[0078] S2: The precursor solution was poured into a polytetrafluoroethylene-lined reactor and reacted at 160°C for 18 hours under sealed conditions. After the reaction, the reactor was cooled to room temperature, then washed and vacuum dried to obtain vanadium disulfide powder. The vacuum drying parameters were: pressure 1.0 MPa and drying temperature 75°C.

[0079] The drying time is 5 hours;

[0080] S3: The vanadium disulfide powder obtained above is heated to 300°C in nitrogen at a heating rate of 60°C / h and annealed for 2 hours. The annealing cycle is 5 hours to obtain a nano-flower-like vanadium disulfide zinc-ion battery cathode material containing sulfur vacancies.

[0081] Example 7

[0082] A method for preparing a nano-flower-like vanadium zinc disulfide cathode material containing sulfur vacancies includes the following steps:

[0083] S1: Add 0.5g of ammonium metavanadate to 20mL of ethylene glycol, and stir evenly in a water bath at a constant temperature of 60℃ to obtain an orange-yellow transparent mixed solution A; add 30mL of deionized water to mixed solution A to obtain mixed solution B;

[0084] Add 2g of thioacetamide to mixed solution B and stir until the thioacetamide is completely dissolved to obtain mixed solution C. Add 25% ammonia solution dropwise to adjust the pH of mixed solution C to 9-11. When the solution turns dark green, the precursor solution is obtained. At this time, the molar ratio of thioacetamide to ammonium metavanadate is 1:0.15, and the concentration of ammonium metavanadate in mixed solution C is about 0.1mol / L.

[0085] S2: The precursor solution was poured into a polytetrafluoroethylene-lined reactor and reacted at 160°C for 20 hours under sealed conditions. After the reaction, the reactor was cooled to room temperature, then washed and vacuum dried to obtain vanadium disulfide powder. The vacuum drying parameters were: pressure 1.0 MPa and drying temperature 75°C.

[0086] The drying time is 5 hours;

[0087] S3: The vanadium disulfide powder obtained above is heated to 300°C in nitrogen at a heating rate of 60°C / h and annealed for 2 hours. The annealing cycle is 5 hours to obtain a nano-flower-like vanadium disulfide zinc-ion battery cathode material containing sulfur vacancies.

[0088] Example 8

[0089] A method for preparing a nano-flower-like vanadium zinc disulfide cathode material containing sulfur vacancies includes the following steps:

[0090] S1: Add 0.5g of ammonium metavanadate to 30mL of ethylene glycol, and stir evenly in a water bath at a constant temperature of 60℃ to obtain an orange-yellow transparent mixed solution A; add 20mL of deionized water to mixed solution A to obtain mixed solution B;

[0091] Add 3g of thioacetamide to mixed solution B and stir until the thioacetamide is completely dissolved to obtain mixed solution C. Add 25% ammonia solution dropwise to adjust the pH of mixed solution C to 9-11. When the solution turns dark green, the precursor solution is obtained. At this time, the molar ratio of thioacetamide to ammonium metavanadate is 1:0.1, and the concentration of ammonium metavanadate in mixed solution C is approximately 0.11 mol / L.

[0092] S2: The precursor solution was poured into a polytetrafluoroethylene-lined reactor and reacted at 160°C for 16 hours under sealed conditions. After the reaction, the reactor was cooled to room temperature, then washed and vacuum dried to obtain vanadium disulfide powder. The vacuum drying parameters were: pressure 1.0 MPa and drying temperature 75°C.

[0093] The drying time is 5 hours;

[0094] S3: The vanadium disulfide powder obtained above is heated to 300°C in nitrogen at a heating rate of 60°C / h and annealed for 2 hours. The annealing cycle is 5 hours to obtain a nano-flower-like vanadium disulfide zinc-ion battery cathode material containing sulfur vacancies.

[0095] Example 9

[0096] A method for preparing a nano-flower-like vanadium zinc disulfide ion cathode material containing sulfur vacancies includes the following steps:

[0097] S1: Add 0.5g of ammonium metavanadate to 30mL of ethylene glycol, and stir evenly in a water bath at a constant temperature of 60℃ to obtain an orange-yellow transparent mixed solution A; add 20mL of deionized water to mixed solution A to obtain mixed solution B;

[0098] Add 1.5g of thioacetamide to mixed solution B and stir until the thioacetamide is completely dissolved to obtain mixed solution C. Add 25% ammonia solution dropwise to adjust the pH of mixed solution C to 9-11. When the solution turns dark green, the precursor solution is obtained. At this time, the molar ratio of thioacetamide to ammonium metavanadate is 1:0.2, and the concentration of ammonium metavanadate in mixed solution C is approximately 0.11mol / L.

[0099] S2: The precursor solution was poured into a polytetrafluoroethylene-lined reactor and reacted at 160°C for 16 hours under sealed conditions. After the reaction, the reactor was cooled to room temperature, then washed and vacuum dried to obtain vanadium disulfide powder. The vacuum drying parameters were: pressure 1.0 MPa and drying temperature 75°C.

[0100] The drying time is 5 hours;

[0101] S3: The vanadium disulfide powder obtained above is heated to 300°C in nitrogen at a heating rate of 60°C / h and annealed for 2 hours. The annealing cycle is 5 hours to obtain a nano-flower-like vanadium disulfide zinc-ion battery cathode material containing sulfur vacancies.

[0102] Example 10

[0103] A method for preparing a nano-flower-like vanadium zinc disulfide cathode material containing sulfur vacancies includes the following steps:

[0104] S1: Add 0.5g of ammonium metavanadate to 20mL of ethylene glycol, and stir evenly in a water bath at a constant temperature of 60℃ to obtain an orange-yellow transparent mixed solution A; add 30mL of deionized water to mixed solution A to obtain mixed solution B;

[0105] Add 2g of thioacetamide to mixed solution B and stir until the thioacetamide is completely dissolved to obtain mixed solution C. Add 25% ammonia solution dropwise to adjust the pH of mixed solution C to 9-11. When the solution turns dark green, the precursor solution is obtained. At this time, the molar ratio of thioacetamide to ammonium metavanadate is 1:0.15, and the concentration of ammonium metavanadate in mixed solution C is about 0.1mol / L.

[0106] S2: The precursor solution was poured into a polytetrafluoroethylene-lined reactor and reacted at 180°C for 20 hours under sealed conditions. After the reaction, the reactor was cooled to room temperature, then washed and vacuum dried to obtain vanadium disulfide powder. The vacuum drying parameters were: pressure 1.0 MPa and drying temperature 75°C.

[0107] The drying time is 5 hours;

[0108] S3: The vanadium disulfide powder obtained above is heated to 300°C in nitrogen at a heating rate of 60°C / h and annealed for 2 hours. The annealing cycle is 5 hours to obtain a nano-flower-like vanadium disulfide zinc-ion battery cathode material containing sulfur vacancies.

[0109] Figure 1 and Figure 2 The images show the XRD and SEM images of the sulfur-vacancy-containing nanoflower-shaped vanadium disulfide zinc-ion battery cathode material prepared in Example 1. The comparison between the XRD images and the PDF card shows that the synthesized sample is vanadium disulfide with extremely high purity and a nanoflower-like morphology, which increases the contact area between the material and the electrolyte, thereby increasing the number of reactive sites.

[0110] Figure 3 This is a comparison of XPS images of vanadium disulfide powder before and after annealing in Example 1. The images show that after annealing, V... 2+ The peaks were significantly enhanced, indicating an increase in their content, which further suggests the presence of sulfur vacancy defects in the material.

[0111] Figures 4-9 The images show scanning electron microscope (SEM) images of the sulfur-vacancy-containing nanoflower-like vanadium disulfide zinc-ion battery cathode materials prepared in Examples 2-7. The images show that increasing the proportion of ethylene glycol in the hydrothermal solvent thins the nanosheets of the vanadium disulfide material, thereby shortening the transport distance of zinc ions during charging and resulting in better electrochemical performance. Furthermore, the size of the vanadium disulfide remains essentially unchanged with increasing hydrothermal time, indicating that the material preparation was complete after 16 hours of reaction.

[0112] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A method for preparing a nanoflower-like vanadium zinc disulfide cathode material containing sulfur vacancies, characterized in that, The method comprises the following steps: S1: using ammonium metavanadate, ethylene glycol, thioacetamide, deionized water and ammonia water as raw materials to prepare a precursor solution; Specifically comprising the following steps: S11: mixing ammonium metavanadate and ethylene glycol and stirring at a constant temperature to obtain a mixed solution A; mixing the mixed solution A and deionized water to obtain a mixed solution B; S22: adding thioacetamide to the mixed solution B to obtain a mixed solution C; adjusting the pH value of the mixed solution C to obtain the precursor solution; S2: performing hydrothermal reaction on the precursor solution, and then performing washing and drying to obtain a vanadium disulfide powder; S3: performing heat treatment on the vanadium disulfide powder to obtain a nano-flower-shaped vanadium disulfide zinc ion battery positive electrode material containing sulfur vacancies; the heat treatment is annealing treatment; the annealing treatment is performed at 200-500 DEG C for 1-4 h in nitrogen; The molar ratio of the thioacetamide to the ammonium metavanadate is 1:(0.05-0.2); the volume ratio of the deionized water to the ethylene glycol is 1:(0.25-4); and the concentration of the ammonium metavanadate in the mixed solution C is 0.08-0.12 mol / L.

2. The preparation method of the sulfur vacancy-containing nanoflower-like vanadium zinc disulfide cathode material of claim 1, characterized in that, The pH value of the mixed solution C is adjusted to 9-11 by using ammonia water with a molar concentration of 25%-30%.

3. The preparation method of the sulfur vacancy-containing nanoflower-like vanadium zinc disulfide cathode material of claim 1, characterized in that, In S11, the constant temperature is performed in a water bath; and the constant temperature is at 60 DEG C.

4. The preparation method of the sulfur-vacancy-containing nanoflower-like vanadium zinc disulfide cathode material of claim 1, characterized in that, In S2, the hydrothermal reaction is performed under a closed condition; the temperature of the hydrothermal reaction is 150-200 DEG C; and the time of the hydrothermal reaction is 10-24 h.

5. The method of claim 1, wherein the method is characterized by: In S2, the drying is performed by using vacuum drying; and the parameters of the vacuum drying are as follows: the pressure is 0.8-1.0 MPa; the drying temperature is 40-80 DEG C; and the drying time is 5-15 h.

6. The method of claim 1, wherein the method is characterized by: The cycle of the annealing treatment is 2-9 h; and the heating rate is 60-300 DEG C / h.

Images