Vanadium selenide / ferrous selenide heterogeneous composite material as well as preparation method and application thereof
By designing a core-shell structure for vanadium selenide/ferrous selenide heterocomposite materials, the problems of poor conductivity and large volume expansion in sodium-ion battery anode materials were solved, achieving high specific capacity, excellent rate performance, and ultra-long cycle stability, making it suitable for sodium-ion battery anode materials.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- 湖州超钠新能源科技有限公司
- Filing Date
- 2026-02-10
- Publication Date
- 2026-05-12
AI Technical Summary
Existing sodium-ion battery anode materials suffer from poor conductivity, large volume expansion, and insufficient cycle stability, making it difficult to meet the requirements for high energy density and long cycle life.
A vanadium selenide/ferrous selenide heterocomposite material was designed with a core-shell structure. Vanadium selenide nanosheets were coated on the surface of ferrous selenide microspheres. The electronic structure and ion diffusion dynamics of the material were optimized through nanosheet-microsphere hierarchical structure and interface engineering.
It achieves high specific capacity, excellent rate performance and ultra-long cycle stability, significantly improving the electrochemical performance of sodium-ion batteries and possessing potential for industrial application.
Smart Images
Figure CN122025587A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of electrochemical energy storage and conversion technology, and more specifically, to a vanadium selenide / ferrous selenide heterocomposite material, its preparation method, and its application. Background Technology
[0002] Sodium-ion batteries, due to their advantages such as abundant sodium resources, low cost, and environmental friendliness, show broad application prospects in large-scale energy storage. However, due to the limited availability of sodium... + The ionic radius (1.02 Å) is greater than that of Li. + The larger (0.76 Å) leads to slow diffusion kinetics in traditional anode materials and easily causes severe volume expansion, which in turn affects the cycle stability and rate performance of the battery. At present, the anode materials of sodium-ion batteries that have been studied more often include: (1) carbon-based materials (such as hard carbon, graphene): have good cycle stability, but low specific capacity (usually <300 mAh / g), which is difficult to meet the high energy density requirements; (2) alloy materials (such as Sn, Sb): have high theoretical capacity, but severe volume expansion (>300%) during charging and discharging, which leads to electrode pulverization and failure; (3) transition metal chalcogenides (TMDs, such as MoS2, FeS2): have high theoretical capacity and layered structure, but poor conductivity and are prone to structural collapse during charging and discharging.
[0003] In recent years, selenides have become a research hotspot for anode materials in sodium-ion batteries due to their high theoretical capacity and good electrochemical activity. Vanadium selenide (V₂Se₃) has a two-dimensional structure and a theoretical capacity of ~500 mAh / g, but it suffers from poor conductivity, leading to poor rate performance; large volume change (~200%) during charge and discharge, which easily damages the electrode structure after long-term cycling; and the easy dissolution of selenium in the electrolyte, causing loss of active material. Ferrous selenide (FeSe) has a stable crystal structure and high electronic conductivity, but its specific capacity is low (~300 mAh / g), making it difficult to meet the high energy density requirements when used alone.
[0004] Heterogeneous composite materials can optimize electronic structure and improve conductivity through synergistic effects between different components; they can also improve ion diffusion kinetics by utilizing built-in electric fields; and enhance mechanical stability through valence bond coupling. For example, MoS2 / FeS2 heterojunctions can improve sodium ion storage performance, but their cycling stability is still insufficient (capacity retention <80% after 100 cycles); VS2 / CoSe2 composites improve conductivity through interface engineering, but their preparation process is complex and difficult to scale up.
[0005] In view of this, the present invention is proposed. Summary of the Invention
[0006] The purpose of this invention is to address the shortcomings of existing technologies by providing a vanadium selenide / ferrous selenide heterocomposite material, its preparation method, and its applications. This composite material consists of vanadium selenide nanosheets coated on the surface of ferrous selenide microspheres, forming a core-shell structure. Through a unique "nanosheet-microsphere" hierarchical structural design and interface engineering optimization, the vanadium selenide / ferrous selenide heterocomposite material of this invention exhibits technical advantages such as high specific capacity and excellent rate performance, synergistic heterostructure effect, and ultra-long cycle stability in sodium-ion battery anode applications.
[0007] This invention is implemented as follows: In a first aspect, the present invention provides a vanadium selenide / ferrous selenide heterocomposite material, wherein the composite material has a core-shell structure, comprising a ferrous selenide microsphere core and vanadium selenide nanosheets coated on the surface of the ferrous selenide microsphere core.
[0008] Secondly, the present invention provides a method for preparing vanadium selenide / ferrous selenide heterocomposite materials, comprising the following steps: A certain amount of vanadium oxysulfate solid powder was heated for the first time under an argon atmosphere, and then the argon was replaced with a mixed gas for the second heating. After cooling, vanadium trioxide powder was obtained. Ferrous sulfate heptahydrate and thioacetamide were dissolved in an aqueous ethylene glycol solution in a certain molar ratio. After stirring until the solid particles were completely dissolved, the mixed solution was subjected to a hydrothermal reaction. After the reaction was completed, the solution was naturally cooled at room temperature, centrifuged, and washed to obtain a solid precipitate. After baking and grinding, ferrous sulfide powder was obtained. Ferrous sulfide powder was soaked in CTAB solution and stirred for a period of time. Vanadium trioxide powder was added and stirred for another period of time. After standing, centrifugation and drying, vanadium trioxide / ferrous sulfide heterocomposite precursor powder was obtained. After thoroughly mixing vanadium trioxide / ferrous sulfide heterocomposite precursor powder with selenium powder at a certain molar ratio, a high-temperature selenization reaction was carried out under argon atmosphere protection to obtain vanadium selenide / ferrous selenide heterocomposite material.
[0009] In some preferred embodiments, the temperature of the first heating is 350-400°C and the heating time is 3-5 hours; the temperature of the second heating is 500-600°C and the heating time is 4-6 hours.
[0010] In some preferred embodiments, the mixed gas is argon and hydrogen, with a volume ratio of argon to hydrogen of (90-95):1.
[0011] In some preferred embodiments, the vanadium trioxide powder is in the form of nano discs with a diameter of 200-300 nm.
[0012] In some preferred embodiments, the molar ratio of ferrous sulfate heptahydrate to 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℃.
[0013] In some preferred embodiments, the ferrous sulfide is spherical with a diameter of 2-5 µm.
[0014] In some preferred embodiments, the concentration of the CTAB solution is 1-1.5 mol / L, and the molar ratio of ferrous sulfide powder to vanadium trioxide powder is (2-5):1.
[0015] In some preferred embodiments, the molar ratio of the vanadium trioxide / ferrous sulfide heterocomposite precursor powder to the selenium powder is (1-3):1, the temperature of the high-temperature selenization reaction is 800-1000℃, and the reaction time is 3-5h.
[0016] Thirdly, the present invention provides an application of vanadium selenide / ferrous selenide heterocomposite material in supercapacitor electrode materials, lithium-ion battery or sodium-ion battery anode materials, and lithium-sulfur battery cathode materials.
[0017] The present invention has the following beneficial effects: The vanadium selenide / ferrous selenide heterocomposite material prepared in this invention achieves breakthroughs in three dimensions—high capacity, long cycle life, and low cost—as a sodium-ion battery anode through a "nanosheet-microsphere" heterostructure design combined with interface charge regulation and core-shell coating protection. It solves the key bottleneck of traditional selenide anode materials and has the potential for industrial application. Attached Figure Description
[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.
[0019] Figure 1 SEM image of vanadium selenide nanosheets provided in an embodiment of the present invention; Figure 2 SEM image of ferrous selenide microspheres provided in an embodiment of the present invention; Figure 3 SEM image of the vanadium selenide / ferrous selenide heterocomposite material provided in the embodiments of the present invention; Figure 40.5 A g of vanadium selenide / ferrous selenide heterocomposite material provided in the embodiments of the present invention -1 Constant current charge-discharge cycle and coulombic efficiency curves, where vanadium selenide and ferrous selenide are experimental control samples; Figure 5 The rate performance test results of the vanadium selenide / ferrous selenide heterocomposite material provided in the embodiments of the present invention are shown, with current densities ranging from 0.5 to 8 A g. -1 The variations were observed, with vanadium selenide and ferrous selenide serving as experimental control samples. Figure 6 The vanadium selenide / ferrous selenide heterocomposite material provided in this invention has Na content calculated during charging via GITT testing. + The diffusion coefficient, where vanadium selenide and ferrous selenide are experimental control samples. Detailed Implementation
[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.
[0021] The following provides a detailed description of a vanadium selenide / ferrous selenide heterocomposite material, its preparation method, and its application.
[0022] In a first aspect, the present invention provides a vanadium selenide / ferrous selenide (V2Se3 / FeSe) heterocomposite material, wherein the composite material has a core-shell structure, comprising a ferrous selenide (FeSe) microsphere core and vanadium selenide (V2Se3) nanosheets coated on the surface of the ferrous selenide microsphere core.
[0023] The vanadium selenide / ferrous selenide heterocomposite material of the present invention has significant technical advantages in sodium-ion battery anode applications through a unique “nanosheet-microsphere” hierarchical structure design and interface engineering optimization: (1) High specific capacity and excellent rate performance: V2Se3 nanosheets provide abundant active sites and short-range Na + Diffusion path, contributing to high theoretical capacity. FeSe microspheres, as a conductive framework, enhance the overall electronic conductivity, enabling the composite material to maintain a high reversible capacity under high current density; (2) Hetero-interface synergistic effect: The band matching between V2Se3 and FeSe forms a built-in electric field, accelerating Na + Migration; (3) Ultra-long cycle stability: Through the tight interfacial coupling of chemical bonds (V-Se-Fe) and the mechanical support of FeSe microspheres, the stripping and volume expansion of V2Se3 active material are effectively buffered, preventing electrode pulverization and reducing capacity decay.
[0024] Secondly, the present invention provides a method for preparing vanadium selenide / ferrous selenide heterocomposite materials, comprising the following steps: S1. A certain amount of vanadium oxysulfate (VOSO4) solid powder is heated for the first time under an argon atmosphere. Then, the argon is replaced with a mixed gas and heated for the second time. After cooling, vanadium trioxide (V2O3) powder is obtained.
[0025] In some preferred embodiments, the temperature of the first heating is 350-400℃, and the heating time is 3-5 hours; the temperature of the second heating is 500-600℃, and the heating time is 4-6 hours. The mixed gas is a mixture of argon and hydrogen, and the volume ratio of argon to hydrogen in the mixed gas is (90-95):1. Both the first and second heating are carried out in a tube furnace.
[0026] In some preferred embodiments, the vanadium trioxide (V2O3) powder is in the form of nano discs with a diameter of 200-300 nm.
[0027] S2. Ferrous sulfate heptahydrate (FeSO4·7H2O) and thioacetamide (TAA) are dissolved in an aqueous ethylene glycol solution in a certain molar ratio. After stirring until the solid particles are completely dissolved, the mixed solution is subjected to a hydrothermal reaction. After the reaction is completed, the solution is naturally cooled at room temperature, centrifuged, washed, and a solid precipitate is obtained. After baking and grinding, ferrous sulfide (FeS) powder is obtained.
[0028] In some preferred embodiments, the molar ratio of FeSO4·7H2O to TAA 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℃.
[0029] In some preferred embodiments, the ferrous sulfide is spherical with a diameter of 2-5 µm.
[0030] It should be noted that steps S1 and S2 are not in any particular order and can be performed simultaneously to prepare FeS and V2O3 powders.
[0031] S3. Soak FeS powder in CTAB solution and stir. After stirring for a period of time, add V2O3 powder and continue stirring for a period of time. Then, after standing, centrifugation and drying, V2O3 / FeS heterocomposite precursor powder is obtained.
[0032] In some preferred embodiments, the concentration of the CTAB solution is 1-1.5 mol / L, and the molar ratio of ferrous sulfide powder to vanadium trioxide powder is (2-5):1; the stirring time is 30 min, preferably using magnetic stirring.
[0033] S4. After thoroughly mixing V2O3 / FeS heterogeneous composite precursor powder and selenium powder at a certain molar ratio, a high-temperature selenization reaction is carried out under argon atmosphere protection to obtain vanadium selenide / ferrous selenide (V2Se3 / FeSe) heterogeneous composite material.
[0034] In some preferred embodiments, the molar ratio of the vanadium trioxide / ferrous sulfide heterocomposite precursor powder to the selenium powder is (1-3):1, the temperature of the high-temperature selenization reaction is 800-1000℃, and the reaction time is 3-5h.
[0035] It should be noted that, in the embodiments of this application, the room temperature involved in the preparation method of V2Se3 / FeSe heterocomposite material is 15-35℃.
[0036] Thirdly, the present invention provides an application of vanadium selenide / ferrous selenide heterocomposite material in supercapacitor electrode materials, lithium-ion battery or sodium-ion battery anode materials, and lithium-sulfur battery cathode materials.
[0037] The features and performance of the present invention will be further described in detail below with reference to embodiments.
[0038] The specific electrochemical test parameters for the V2Se3 / FeSe heterocomposite material synthesized in this application, used as the negative electrode of a sodium-ion battery, are as follows: A CR2032 button cell casing is used; the negative electrode of the assembled half-cell is a sodium metal disc with a diameter of 16 mm; the positive electrode is prepared by mixing the V2Se3 / FeSe composite material, superconducting carbon black, and polyvinylidene fluoride dissolved in NMP at a mass ratio of 7:2:1; the separator is a Whatman glass fiber disc (model GF / C) with a diameter of 19 mm; and the electrolyte is 1M NaPF6 dissolved in diethylene glycol dimethyl ether (DIGLYME). The battery is assembled in a glove box protected by an argon atmosphere with water and oxygen content both below 0.1 ppm.
[0039] Example 1 This embodiment provides a method for preparing vanadium selenide / ferrous selenide heterocomposite material, which includes the following steps: S1. Place 5 g of VOSO4 solid powder in a ceramic boat, place it in a tube furnace, purge with argon gas (flow rate 50 mL / min), heat to 350℃, and hold for 4 hours; switch to an argon / hydrogen mixture (volume ratio 95:1), raise the temperature to 500℃, hold for 4 hours, and after cooling, obtain V2O3 nanospheres, as shown below. Figure 1 As shown, the diameter of the nanosheet is approximately 250 nm; S2. Dissolve 0.278 g FeSO4·7H2O and 0.15 g thioacetamide in 50 mL of ethylene glycol aqueous solution (1:1 volume ratio). Stir magnetically for 30 minutes, transfer to an autoclave, and react at 160℃ for 12 hours. After centrifugation and drying, FeS microspheres are obtained. Figure 2 As shown, FeS is a sphere formed by stacking sheets, with a diameter of approximately 3.5 μm.
[0040] S3. Soak 0.176 g FeS microspheres in 20 mL of 1 mol / L CTAB solution and stir for 30 minutes. Add 0.15 g V2O3 nano discs and continue stirring for 30 minutes. Let stand for 24 hours, centrifuge and dry to obtain V2O3 / FeS precursor powder.
[0041] S4. Mix 0.238 g of V2O3 / FeS precursor powder with 0.0395 g of Se powder, heat to 1000 ℃ under argon protection, maintain for 4 hours, and after cooling, obtain a V2Se3 / FeSe heterocomposite material with nanosheets coated with microspheres, as shown below. Figure 3 As shown, V2Se3 nanosheets are uniformly coated on the surface of FeSe microspheres.
[0042] Then, V2Se3 / FeSe heterocomposite superconducting carbon black and PVDF were mixed at a mass ratio of 7:2:1, and the concentration was adjusted with N-methylpyrrolidone. The mixture was stirred for 2 hours to prepare a slurry. The prepared slurry was coated onto a 14 mm diameter circular nickel foam current collector, dried in an oven at 70 °C for 24 hours, and then pressed into tablets at a pressure of about 8 MPa using a tablet press. Sodium-ion coin half-cells were then assembled for testing.
[0043] The constant current charge-discharge cycle and coulombic efficiency curves obtained from the test are as follows: Figure 4 As shown, the results indicate that the V2Se3 / FeSe heterocomposite prepared in this example exhibits good performance at 0.5 A g. -1 The initial discharge specific capacity at the specified current density is 570.2 mAh g. -1 After 100 cycles, it still retains 313.5 mAh g. -1 The initial specific capacities of the control samples V₂Se₃ and FeSe were 530.3 and 467.5 mAh g⁻¹, respectively. -1 After 100 cycles, the capacity decreased to 270.9 and 209.5 mAh g. -1 .
[0044] Rate performance of V2Se3 / FeSe heterocomposite materials, test results are as follows: Figure 5 As shown, when the current density is from 0.5 to 8 Ag... -1When the ratio varies, the rate performance of the V2Se3 / FeSe composite is significantly better than that of the single-component V2Se3 or FeSe.
[0045] Na content of V2Se3 / FeSe heterocomposite material was calculated by GITT test. + Diffusion coefficient, the results are as follows Figure 6 As shown, during the 0-2.5V charging process, the ion diffusion coefficient of the composite material is significantly greater than that of the single component in most processes.
[0046] As can be seen from the above, compared with single-component V2Se3 or FeSe, the V2Se3 / FeSe heterocomposite material synthesized in this embodiment achieves high specific capacity and excellent rate performance. This should be attributed to the effective dispersion of V2Se3 nanosheets by FeSe microspheres, providing abundant active sites and reaction surface area; at the same time, the electric field at the heterostructure interface helps to accelerate ion migration, thereby bringing about Na + Improvements in kinetic properties such as diffusion coefficient and magnification.
[0047] Example 2 This embodiment provides a method for preparing vanadium selenide / ferrous selenide heterocomposite material, which includes the following steps: S1. Place 5 g of VOSO4 solid powder in a ceramic boat, put it into a tube furnace, introduce argon gas (flow rate 50 mL / min), heat to 400 ℃, and hold for 5 hours; switch to argon / hydrogen mixed gas (volume ratio 90:1), heat to 600 ℃, hold for 6 hours, and obtain V2O3 nano discs after cooling. S2. Dissolve 0.278 g FeSO4·7H2O and 0.30 g thioacetamide in 50 mL of ethylene glycol aqueous solution with a volume ratio of 1:1, stir magnetically for 30 minutes, transfer to an autoclave, react at 180 ℃ for 24 hours, and obtain FeS microspheres after centrifugation and drying. S3. Soak 0.44 g FeS microspheres in 20 mL of 1 mol / L CTAB solution and stir for 30 minutes. Add 0.15 g V2O3 nano discs and continue stirring for 30 minutes. Let stand for 24 hours, centrifuge and dry to obtain V2O3 / FeS precursor powder. S4. Mix 0.357 g of V2O3 / FeS precursor powder with 0.0395 g of Se powder, heat to 800 °C under argon protection, maintain for 6 hours, and cool to obtain V2Se3 / FeSe heterocomposite material with nanosheets coated with microspheres.
[0048] A slurry was prepared by mixing V2Se3 / FeSe composite material, superconducting carbon black, and PVDF at a mass ratio of 7:2:1, adjusting the concentration with N-methylpyrrolidone, and stirring for 2 hours. The prepared slurry was then coated onto a 14 mm diameter circular nickel foam current collector, dried in an oven at 70 °C for 24 hours, and pressed into tablets at approximately 8 MPa using a tablet press. Sodium-ion coin half-cells were then assembled for testing.
[0049] The V₂Se₃ / FeSe heterocomposite material prepared in this example was prepared at 0.5 A g. -1 The initial discharge specific capacity at the given current density is 524.4 mAh g. -1 It still retains 286.3 mAh g-1 after 100 cycles.
[0050] Example 3 This embodiment provides a method for preparing vanadium selenide / ferrous selenide heterocomposite material, which includes the following steps: S1. Place 5 g of VOSO4 solid powder in a ceramic boat, put it into a tube furnace, introduce argon gas (flow rate 50 mL / min), heat to 350 °C, and hold for 3 hours; switch to argon / hydrogen mixed gas (volume ratio 92:1), raise the temperature to 550 °C, hold for 5 hours, and cool to obtain V2O3 nano discs. S2. Dissolve 0.278 g FeSO4·7H2O and 0.225 g thioacetamide in 50 mL of ethylene glycol aqueous solution with a volume ratio of 1:1. Stir magnetically for 30 minutes, transfer to an autoclave, react at 170 °C for 18 hours, and obtain FeS microspheres after centrifugation and drying.
[0051] S3. Soak 0.264 g FeS microspheres in 20 mL of 1 mol / L CTAB solution and stir for 30 minutes. Add 0.15 g V2O3 nano discs and continue stirring for 30 minutes. Let stand for 24 hours, centrifuge and dry to obtain V2O3 / FeS precursor powder.
[0052] S4. Mix 0.119 g of V2O3 / FeS precursor powder with 0.0395 g of Se powder, heat to 900 °C under argon protection, maintain for 3 hours, and cool to obtain V2Se3 / FeSe heterocomposite material with nanosheets coated with microspheres.
[0053] A slurry was prepared by mixing V2Se3 / FeSe composite material, superconducting carbon black, and PVDF at a mass ratio of 7:2:1, adjusting the concentration with N-methylpyrrolidone, and stirring for 2 hours. The prepared slurry was then coated onto a 14 mm diameter circular nickel foam current collector, dried in an oven at 70 °C for 24 hours, and pressed into tablets at approximately 8 MPa using a tablet press. Sodium-ion coin half-cells were then assembled for testing.
[0054] The V₂Se₃ / FeSe heterocomposite material prepared in this example was prepared at 0.5 A g. -1 The initial discharge specific capacity at the given current density is 556.7 mAh g. -1 It still retains 301.6 mAh g after 100 cycles. -1 .
[0055] Example 4 This embodiment provides a method for preparing vanadium selenide / ferrous selenide heterocomposite material, which includes the following steps: S1. Place 5 g of VOSO4 solid powder in a ceramic boat, put it into a tube furnace, introduce argon gas (flow rate 50 mL / min), heat to 350 °C, and hold for 4 hours; switch to argon / hydrogen mixed gas (volume ratio 90:1), heat to 500 °C, hold for 5 hours, and obtain V2O3 nano discs after cooling. S2. Dissolve 0.278 g FeSO4·7H2O and 0.15 g thioacetamide in 50 mL of ethylene glycol aqueous solution with a volume ratio of 1:1. Stir magnetically for 30 minutes, transfer to an autoclave, react at 160 °C for 12 hours, and obtain FeS microspheres after centrifugation and drying.
[0056] S3. Soak 0.352 g FeS microspheres in 20 mL of 1 mol / L CTAB solution and stir for 30 minutes. Add 0.15 g V2O3 nano discs and continue stirring for 30 minutes. Let stand for 24 hours, centrifuge and dry to obtain V2O3 / FeS precursor powder.
[0057] S4. Mix 0.238 g of V2O3 / FeS precursor powder with 0.0395 g of Se powder, heat to 1000 °C under argon protection, maintain for 4 hours, and cool to obtain V2Se3 / FeSe heterocomposite material with nanosheets coated with microspheres.
[0058] A slurry was prepared by mixing V2Se3 / FeSe composite material, superconducting carbon black, and PVDF at a mass ratio of 7:2:1, adjusting the concentration with N-methylpyrrolidone, and stirring for 2 hours. The prepared slurry was then coated onto a 14 mm diameter circular nickel foam current collector, dried in an oven at 70 °C for 24 hours, and pressed into tablets at approximately 8 MPa using a tablet press. Sodium-ion coin half-cells were then assembled for testing.
[0059] The V₂Se₃ / FeSe heterocomposite material prepared in this example was prepared at 0.5 A g. -1 The initial discharge specific capacity at the given current density is 583.3 mAh g. -1 After 100 cycles, it still retains 295.1 mAh g.-1 .
[0060] Example 5 This embodiment provides a method for preparing vanadium selenide / ferrous selenide heterocomposite material, which includes the following steps: S1. Place 5 g of VOSO4 solid powder in a ceramic boat, put it into a tube furnace, introduce argon gas (flow rate 50 mL / min), heat to 350 ℃, and hold for 4 hours; switch to argon / hydrogen mixed gas (volume ratio 92:1), heat to 500 ℃, hold for 4 hours, and cool to obtain V2O3 nano discs. S2. Dissolve 0.278 g FeSO4·7H2O and 0.15 g thioacetamide in 50 mL of ethylene glycol aqueous solution with a volume ratio of 1:1. Stir magnetically for 30 minutes, transfer to an autoclave, react at 170 °C for 20 hours, and obtain FeS microspheres after centrifugation and drying.
[0061] S3. Soak 0.176 g FeS microspheres in 20 mL of 1 mol / L CTAB solution and stir for 30 minutes. Add 0.15 g V2O3 nano discs and continue stirring for 30 minutes. Let stand for 24 hours, centrifuge and dry to obtain V2O3 / FeS precursor powder.
[0062] S4. Mix 0.119 g of V2O3 / FeS precursor powder with 0.0395 g of Se powder, heat to 1000 °C under argon protection, maintain for 5 hours, and cool to obtain V2Se3 / FeSe heterocomposite material with nanosheets coated with microspheres.
[0063] A slurry was prepared by mixing V2Se3 / FeSe composite material, superconducting carbon black, and PVDF at a mass ratio of 7:2:1, adjusting the concentration with N-methylpyrrolidone, and stirring for 2 hours. The prepared slurry was then coated onto a 14 mm diameter circular nickel foam current collector, dried in an oven at 70 °C for 24 hours, and pressed into tablets at approximately 8 MPa using a tablet press. Sodium-ion coin half-cells were then assembled for testing.
[0064] The V₂Se₃ / FeSe heterocomposite material prepared in this example was prepared at 0.5 A g. -1 The initial discharge specific capacity at the given current density is 543.8 mAh g. -1 After 100 cycles, it still retains 307.9 mAh g. -1 .
[0065] Example 6 This embodiment provides a method for preparing vanadium selenide / ferrous selenide heterocomposite material, which includes the following steps: S1. Place 5 g of VOSO4 solid powder in a ceramic boat, put it into a tube furnace, introduce argon gas (flow rate 50 mL / min), heat to 380 ℃, and hold for 5 hours; switch to argon / hydrogen mixed gas (volume ratio 95:1), raise the temperature to 550 ℃, hold for 6 hours, and obtain V2O3 nano discs after cooling. S2. Dissolve 0.278 g FeSO4·7H2O and 0.225 g thioacetamide in 50 mL of ethylene glycol aqueous solution with a volume ratio of 1:1. Stir magnetically for 30 minutes, transfer to an autoclave, react at 180 °C for 24 hours, and obtain FeS microspheres after centrifugation and drying.
[0066] S3. Soak 0.264 g FeS microspheres in 20 mL of 1 mol / L CTAB solution and stir for 30 minutes. Add 0.15 g V2O3 nano discs and continue stirring for 30 minutes. Let stand for 24 hours, centrifuge and dry to obtain V2O3 / FeS precursor powder.
[0067] S4. Mix 0.357 g of V2O3 / FeS precursor powder with 0.0395 g of Se powder, heat to 900 °C under argon protection, maintain for 3 hours, and cool to obtain V2Se3 / FeSe heterocomposite material with nanosheets coated with microspheres.
[0068] A slurry was prepared by mixing V2Se3 / FeSe composite material, superconducting carbon black, and PVDF at a mass ratio of 7:2:1, adjusting the concentration with N-methylpyrrolidone, and stirring for 2 hours. The prepared slurry was then coated onto a 14 mm diameter circular nickel foam current collector, dried in an oven at 70 °C for 24 hours, and pressed into tablets at approximately 8 MPa using a tablet press. Sodium-ion coin half-cells were then assembled for testing.
[0069] The V₂Se₃ / FeSe heterocomposite material prepared in this example was prepared at 0.5 A g. -1 The initial discharge specific capacity at the given current density is 531.0 mAh g. -1 After 100 cycles, it still retains 290.6 mAh g. -1 .
[0070] In summary, the V₂Se₃ / FeSe heterocomposite material demonstrates significant advantages as a high-performance anode material for sodium-ion batteries. Its core value lies in the successful synergistic effect of V₂Se₃ nanosheets and FeSe microspheres achieved through ingenious heterostructure design. In terms of electrochemical performance, this composite material exhibits a higher initial discharge specific capacity (optimal value reaching 583.3 mAh g⁻¹) than either single component (V₂Se₃ or FeSe). -¹), and it also demonstrates outstanding long-term cycling stability, with excellent capacity retention after 100 cycles (optimal retention capacity of 313.5 mAh g). - ¹). More importantly, this material exhibits excellent rate performance, even at high current densities (8 A g). - ¹) It can still maintain a high reversible capacity, which is directly attributed to the significant increase in Na during charge and discharge, as confirmed by GITT testing. + Diffusion coefficient. These excellent kinetic properties are fundamentally due to its unique microstructure: FeSe microspheres act as a supporting framework, effectively preventing the aggregation of V2Se3 nanosheets and exposing more electrochemical active sites; at the same time, the heterojunction formed at the interface induces a built-in electric field, which acts as a highly efficient ion / electron transport channel, greatly accelerating the charge transfer process and potentially effectively buffering volume changes during cycling, thus jointly endowing the material with high specific capacity, excellent rate capability, and stable long cycle life.
[0071] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.
Claims
1. A vanadium selenide / ferrous selenide heterocomposite material, characterized in that, The composite material has a core-shell structure, comprising an iron selenide microsphere core and vanadium selenide nanosheets coated on the surface of the iron selenide microsphere core.
2. A method for preparing the vanadium selenide / ferrous selenide heterocomposite material as described in claim 1, characterized in that, Includes the following steps: A certain amount of vanadium oxysulfate solid powder was heated for the first time under an argon atmosphere, and then the argon was replaced with a mixed gas for the second heating. After cooling, vanadium trioxide powder was obtained. Ferrous sulfate heptahydrate and thioacetamide were dissolved in an aqueous ethylene glycol solution in a certain molar ratio. After stirring until the solid particles were completely dissolved, the mixed solution was subjected to a hydrothermal reaction. After the reaction was completed, the solution was naturally cooled at room temperature, centrifuged, and washed to obtain a solid precipitate. After baking and grinding, ferrous sulfide powder was obtained. Ferrous sulfide powder was soaked in CTAB solution and stirred for a period of time. Vanadium trioxide powder was added and stirred for another period of time. After standing, centrifugation and drying, vanadium trioxide / ferrous sulfide heterocomposite precursor powder was obtained. After thoroughly mixing vanadium trioxide / ferrous sulfide heterocomposite precursor powder with selenium powder at a certain molar ratio, a high-temperature selenization reaction was carried out under argon atmosphere protection to obtain vanadium selenide / ferrous selenide heterocomposite material.
3. The method for preparing a vanadium selenide / ferrous selenide heterocomposite material according to claim 2, characterized in that, The first heating temperature is 350-400℃, and the heating time is 3-5 hours; the second heating temperature is 500-600℃, and the heating time is 4-6 hours.
4. The method for preparing a vanadium selenide / ferrous selenide heterocomposite material according to claim 2, characterized in that, The mixed gas is argon and hydrogen, with a volume ratio of argon to hydrogen of (90-95):
1.
5. The method for preparing a vanadium selenide / ferrous selenide heterocomposite material according to claim 2, characterized in that, The vanadium trioxide powder is in the form of nano discs with a diameter of 200-300 nm.
6. The method for preparing a vanadium selenide / ferrous selenide heterocomposite material according to claim 2, characterized in that, The molar ratio of ferrous sulfate heptahydrate to 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℃, and the reaction time is 12-24h; the drying temperature is 55-60℃.
7. The method for preparing a vanadium selenide / ferrous selenide heterocomposite material according to claim 2, characterized in that, The ferrous sulfide is spherical with a diameter of 2-5µm.
8. The method for preparing a vanadium selenide / ferrous selenide heterocomposite material according to claim 2, characterized in that, The concentration of the CTAB solution is 1-1.5 mol / L, and the molar ratio of ferrous sulfide powder to vanadium trioxide powder is (2-5):
1.
9. The method for preparing a vanadium selenide / ferrous selenide heterocomposite material according to claim 2, characterized in that, The molar ratio of the vanadium trioxide / ferrous sulfide heterocomposite precursor powder to the selenium powder is (1-3):1, the temperature of the high-temperature selenization reaction is 800-1000℃, and the reaction time is 3-5h.
10. The application of the vanadium selenide / ferrous selenide heterocomposite material as described in claim 1 in supercapacitor electrode materials, lithium-ion battery or sodium-ion battery anode materials, and lithium-sulfur battery cathode materials.