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CN-122025587-A - Vanadium selenide/ferrous selenide heterogeneous composite material and preparation method and application thereof

CN122025587ACN 122025587 ACN122025587 ACN 122025587ACN-122025587-A

Abstract

The invention discloses a vanadium selenide/ferrous selenide heterogeneous composite material, a preparation method and application thereof, and relates to the technical field of electrochemical energy storage and conversion. The vanadium trioxide nano-sheet is prepared by high-temperature decomposition and reduction of vanadyl sulfate, ferrous sulfide microsphere is prepared by hydrothermal reaction of ferrous sulfate heptahydrate and thioacetamide, and then the vanadium trioxide nano-sheet is mixed with the ferrous sulfide microsphere and subjected to high-temperature selenization to prepare the vanadium selenide/ferrous selenide heterogeneous composite material with the vanadium selenide nano-sheet coated on the surface of the ferrous selenide microsphere. The invention is applied to the negative electrode of the sodium ion battery by unique hierarchical structure design and interface engineering optimization, and the prepared vanadium selenide/ferrous selenide composite material is expected to solve the key problems of easy dissolution, volume expansion and the like of the traditional vanadium selenide, has the technical advantages of high capacity, long circulation, low cost preparation and the like, and has industrialized application potential.

Inventors

  • NI WENBIN
  • LIU HANG
  • CAI YURONG
  • WU JUN
  • ZHA WEIWEI
  • ZHOU XIAOCHONG

Assignees

  • 湖州超钠新能源科技有限公司

Dates

Publication Date
20260512
Application Date
20260210

Claims (10)

  1. 1. The vanadium selenide/ferrous selenide heterogeneous composite material is characterized by being of a core-shell structure and comprising a ferrous selenide microsphere inner core and a vanadium selenide nano sheet coated on the surface of the ferrous selenide microsphere inner core.
  2. 2. A method of preparing the vanadium selenide/ferrous selenide heterogeneous composite of claim 1, comprising the steps of: Heating a certain amount of vanadyl sulfate solid powder for the first time under the protection of argon atmosphere, then changing argon into mixed gas, heating for the second time, and cooling to obtain vanadium trioxide powder; Sequentially dissolving ferrous sulfate heptahydrate and thioacetamide into glycol aqueous solution according to a certain molar ratio, stirring until solid particles are completely dissolved, carrying out hydrothermal reaction on the mixed solution, naturally cooling at room temperature after the reaction is completed, centrifuging, washing to obtain solid precipitate, and drying and grinding to obtain ferrous sulfide powder; Soaking ferrous sulfide powder in CTAB solution, stirring, adding vanadium trioxide powder after stirring for a period of time, continuing stirring for a period of time, and then standing, centrifuging and drying to obtain vanadium trioxide/ferrous sulfide heterogeneous composite precursor powder; Fully mixing vanadium trioxide/ferrous sulfide heterogeneous composite precursor powder and selenium powder according to a certain molar ratio, and carrying out high-temperature selenizing reaction under the protection of argon atmosphere to obtain the vanadium selenide/ferrous selenide heterogeneous composite material.
  3. 3. The method for preparing the vanadium selenide/ferrous selenide heterogeneous composite according to claim 2, wherein the temperature of the first heating is 350-400 ℃, the heating time is 3-5h, the temperature of the second heating is 500-600 ℃, and the heating time is 4-6h.
  4. 4. The method for preparing the vanadium selenide/ferrous selenide heterogeneous composite material according to claim 2, wherein the mixed gas is argon and hydrogen, and the volume ratio of the argon to the hydrogen is (90-95): 1.
  5. 5. The method for preparing the vanadium selenide/ferrous selenide heterogeneous composite material according to claim 2, wherein the vanadium trioxide powder is in a nano round plate shape with a diameter of 200-300nm.
  6. 6. The method for preparing the vanadium selenide/ferrous selenide heterogeneous composite material according to claim 2, wherein the molar ratio of the ferrous sulfate heptahydrate to the thioacetamide is 1 (2-4), the volume ratio of ethylene glycol to water in the ethylene glycol aqueous solution is 1:1, the hydrothermal reaction temperature is 160-180 ℃, the reaction time is 12-24h, and the drying temperature is 55-60 ℃.
  7. 7. The method for preparing a heterogeneous composite material of vanadium selenide/ferrous selenide according to claim 2, wherein the ferrous sulfide is spherical and has a diameter of 2 to 5 μm.
  8. 8. The method for preparing a heterogeneous composite material of vanadium selenide/ferrous selenide according to claim 2, wherein the concentration of the CTAB solution is 1 to 1.5mol/L, and the molar ratio of the ferrous sulfide powder to the vanadium trioxide powder is (2 to 5): 1.
  9. 9. The method for preparing the vanadium selenide/ferrous selenide heterogeneous composite material according to claim 2, wherein the molar ratio of the vanadium trioxide/ferrous sulfide heterogeneous composite precursor powder to the selenium powder is (1-3): 1, the high-temperature selenizing reaction temperature is 800-1000 ℃, and the reaction time is 3-5h.
  10. 10. Use of the vanadium selenide/ferrous selenide heterogeneous composite material according to claim 1 in supercapacitor electrode materials, lithium ion batteries or sodium ion battery anode materials and lithium sulfur battery cathode materials.

Description

Vanadium selenide/ferrous selenide heterogeneous composite material and preparation method and application thereof Technical Field The invention relates to the technical field of electrochemical energy storage and conversion, in particular to a vanadium selenide/ferrous selenide heterogeneous composite material, and a preparation method and application thereof. Background The sodium ion battery has the advantages of abundant sodium resources, low cost, environmental friendliness and the like, and has wide application prospect in the field of large-scale energy storage. However, since Na + has a larger ionic radius (1.02 a) than Li + (0.76 a), diffusion kinetics in the conventional anode material is slow, and serious volume expansion is easily caused, thereby affecting the cycle stability and rate performance of the battery. At present, more sodium ion battery cathode materials are researched, which mainly comprise (1) carbon-based materials (such as hard carbon and graphene) with better circulation stability and lower specific capacity (generally less than 300 mAh/g) which are difficult to meet the requirement of high energy density, (2) alloy materials (such as Sn and Sb) with high theoretical capacity and serious volume expansion (> 300%) in the charge and discharge process, which cause electrode pulverization and failure, and (3) transition metal chalcogenide compounds (TMDs such as MoS 2、FeS2) with higher theoretical capacity and lamellar structure, but with poor conductivity, and the structure is easy to collapse in the charge and discharge process. In recent years, selenide has become a research hot spot of sodium ion battery anode materials due to its higher theoretical capacity and good electrochemical activity. Vanadium selenide (V 2Se3) has a two-dimensional structure, the theoretical capacity can reach 500-mAh/g, but the conductivity is poor, the rate performance is poor, the volume change in the charging and discharging process is large (200%), the electrode structure is easy to damage after long-term circulation, selenium element is easy to dissolve in electrolyte, active substance loss is caused, and the like. Ferrous selenide (FeSe) has a stable crystal structure and high electron conductivity, but has low specific capacity (300-mAh/g), and is difficult to meet the requirement of high energy density when used alone. The heterostructure composite material can optimize the electronic structure of the material through the synergistic effect of different components, improve the conductivity, improve the ion diffusion dynamics by utilizing a built-in electric field, and strengthen the mechanical stability of the material through valence bond coupling. For example, moS 2/FeS2 heterojunction can improve the storage performance of sodium ions, but the cycling stability is still insufficient (capacity retention rate is less than 80% after 100 cycles), and VS 2/CoSe2 compound improves the conductivity through interface engineering, but the preparation process is complex and difficult to scale. In view of this, the present invention has been made. Disclosure of Invention The invention aims at overcoming the defects of the prior art and provides a vanadium selenide/ferrous selenide heterogeneous composite material, a preparation method and application thereof. The vanadium selenide/ferrous selenide heterogeneous composite material provided by the invention has the technical advantages of high specific capacity, excellent rate capability, heterogeneous interface synergistic effect, ultra-long cycle stability and the like in the application of a sodium ion battery cathode through unique design of a nano sheet-microsphere hierarchical structure and interface engineering optimization. The invention is realized in the following way: In a first aspect, the invention provides a vanadium selenide/ferrous selenide heterogeneous composite material, which has a core-shell structure and comprises a ferrous selenide microsphere inner core and a vanadium selenide nano sheet coated on the surface of the ferrous selenide microsphere inner core. In a second aspect, the invention provides a method for preparing a vanadium selenide/ferrous selenide heterogeneous composite material, comprising the following steps: Heating a certain amount of vanadyl sulfate solid powder for the first time under the protection of argon atmosphere, then changing argon into mixed gas, heating for the second time, and cooling to obtain vanadium trioxide powder; Sequentially dissolving ferrous sulfate heptahydrate and thioacetamide into glycol aqueous solution according to a certain molar ratio, stirring until solid particles are completely dissolved, carrying out hydrothermal reaction on the mixed solution, naturally cooling at room temperature after the reaction is completed, centrifuging, washing to obtain solid precipitate, and drying and grinding to obtain ferrous sulfide powder; Soaking ferrous sulfide powder in CTAB solution, stirring, ad