Preparation method of SnSe / Fe3Se4 / rGO@NC composite material

Abstract

The application relates to a preparation method of a SnSe / Fe3Se4 / rGO@NC composite material, which comprises the following steps: step 1, adding graphene oxide into a solution and carrying out ultrasonic treatment to obtain a uniform dispersion solution A; step 2, adding the solution A into a high-pressure reaction kettle containing a tin salt and an iron salt; step 3, adding an organic matter on the basis of step 2 to obtain a black solution B; step 4, transferring the black solution B into the high-pressure reaction kettle to carry out a solvothermal reaction and obtain a precursor powder; step 5, physically mixing the precursor powder with selenium powder, placing the mixture in a tube furnace and calcining in an argon atmosphere to obtain SnSe / Fe3Se4 / rGO; step 6, uniformly dispersing the SnSe / Fe3Se4 / rGO into an aqueous solution containing PVP, carrying out suction filtration, drying and obtaining SnSe / Fe3Se4 / rGO@PVP; and step 7, placing appropriate SnSe / Fe3Se4 / rGO@PVP in a tube furnace and calcining in an argon atmosphere to obtain SnSe / Fe3 Se4 / rGO@NC. The solvothermal reaction and the low-temperature sintering method used in the application have the advantages of clear control parameters, easy control of purity, simple operation, good process repeatability and low cost.

Description

Technical Field

[0001] This invention belongs to the field of sodium-ion secondary battery technology, and relates to a method for preparing a SnSe / Fe3Se4 / rGO@NC composite material, and more particularly to a method for preparing a high-performance SnSe / Fe3Se4 / rGO@NC composite material for sodium-ion battery anodes. Background Technology

[0002] As people place higher demands on the cleanliness and economic efficiency of fuels, new energy sources have attracted widespread attention. However, new energy sources are intermittent and their supply is limited by time and space. Therefore, it is crucial to develop energy storage devices for renewable and clean energy.

[0003] Sodium shares similar properties with lithium and is abundant and widely distributed, making it a viable alternative to lithium-ion batteries. Therefore, sodium-ion batteries are considered the most promising replacement for lithium-ion batteries. Among current anode materials, metal selenides have attracted widespread attention due to their high theoretical specific capacity, suitable redox potential, and environmental friendliness. However, metal selenides suffer from a large volume effect when used as anode materials in sodium-ion batteries. Excessive volume changes during charge and discharge can lead to structural collapse, causing a sharp decline in the electrochemical performance of the anode material and affecting the battery's cycle stability. Summary of the Invention

[0004] To address the aforementioned technical problems, the present invention aims to provide a method for preparing SnSe / Fe3Se4 / rGO@NC composite materials.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: The preparation method of SnSe / Fe3Se4 / rGO@NC composite material includes the following steps: Step 1: Add graphene oxide to the solution and sonicate to obtain a uniform dispersion A; Step 2: Add dispersion A to a high-pressure reactor containing tin salt and iron salt, and stir magnetically for 6-8 hours; Step 3: Add organic matter based on Step 2, and continue magnetic stirring for 2-3 hours to obtain black solution B; Step 4: Seal the high-pressure reactor and carry out a solvothermal reaction to obtain precursor powder; Step 5: Physically mix the precursor powder with selenium powder and place it in a tube furnace for calcination in an argon atmosphere to obtain SnSe / Fe3Se4 / rGO; Step 6: Disperse SnSe / Fe3Se4 / rGO uniformly in an aqueous solution containing PVP, filter, and dry to obtain SnSe / Fe3Se4 / rGO@PVP; Step 7: Place an appropriate amount of SnSe / Fe3Se4 / rGO@PVP in a tube furnace and calcine it in an argon atmosphere to obtain SnSe / Fe3Se4 / rGO@NC.

[0006] Preferably, in the preparation method of the SnSe / Fe3Se4 / rGO@NC composite material, the solution is prepared by mixing N,N-dimethylformamide and methanol at a volume ratio of 7:1, wherein the concentration of graphene oxide is 1.25 g·L⁻¹. -1 .

[0007] Preferably, in the preparation method of the SnSe / Fe3Se4 / rGO@NC composite material, the molar ratio of tin salt to iron salt is 2:1, wherein the tin salt is SnCl4∙5H2O and the iron salt is FeSO4∙7H2O.

[0008] Preferably, in the preparation method of the SnSe / Fe3Se4 / rGO@NC composite material, the organic compound is at least one of 2-methylimidazole and imidazole.

[0009] Preferably, in the preparation method of the SnSe / Fe3Se4 / rGO@NC composite material, the temperature of the solvothermal reaction is 110–160 °C.

[0010] Preferably, in the preparation method of the SnSe / Fe3Se4 / rGO@NC composite material, the precursor powder and selenium powder are physically mixed by grinding or ball milling.

[0011] Preferably, in the preparation method of the SnSe / Fe3Se4 / rGO@NC composite material, the concentration of the PVP aqueous solution is 0.02–0.05 g / L. -1 The calcination temperature is 450–650℃, and the time is 1–3 h.

[0012] Preferably, the preparation method of the SnSe / Fe3Se4 / rGO@NC composite material includes the following steps: Step 1: Add 10 mg of graphene oxide to a mixed solution containing 7 mL of N,N-dimethylformamide and 1 mL of methanol, and sonicate for 10 min to obtain a uniform dispersion A; Step 2: Add dispersion A to a high-pressure reactor containing 27.8 mg FeSO4∙7H2O and 70.1 mg SnCl4∙5H2O, and stir magnetically for 6 h; Step 3: Add 65.6 mg of 2-methylimidazole to the mixture from Step 2, and continue stirring for 2 hours; Step 4: After sealing the high-pressure reactor, react at 120℃ for 24 hours; Step 5: Physically mix the precursor and selenium powder at a mass ratio of 2:3, and heat at a rate of 5°C / min under an Ar atmosphere. -1 Calcination at 550℃ for 2 h yielded SnSe / Fe3Se4 / rGO; Step 6: Disperse 100 mg SnSe / Fe3Se4 / rGO in 7.5 mL of distilled water, and add 5 mL of 0.025 g·L⁻¹. -1 A polyvinylpyrrolidone aqueous solution was mixed thoroughly, filtered, and dried to obtain SnSe / Fe3Se4 / rGO@PVP; Step 7: Place SnSe / Fe3Se4 / rGO@PVP into a tube furnace and heat at a rate of 5 °C / min under an Ar atmosphere. -1 Calcination at 550℃ for 2 h yielded SnSe / Fe3Se4 / rGO@NC.

[0013] By means of the above-described solution, the present invention has at least the following advantages: 1. This invention proposes a dual-carbon-layer protected dual-metal selenide (SnSe / Fe3Se4) heterostructure for use in sodium-ion battery anode materials. Due to the presence of a heterogeneous interface, the heterostructure design not only reduces ion diffusion resistance and promotes rapid redox reactions, but also provides more sites for electrochemical reactions. At the same time, the dual-carbon layer can alleviate the volume changes that occur during charge and discharge, thereby improving the cycle stability of the battery.

[0014] 2. The solvothermal reaction and low-temperature sintering method used in this invention has the advantages of clear control parameters, easy purity control, simple operation, good process repeatability and low cost. The heterostructure and double carbon layer coating can not only accelerate the transfer rate of ions and electrons, but also effectively alleviate the volume change caused by sodium ion insertion / extraction, thereby improving the coulombic efficiency, cycle stability and rate performance of metal selenide as a negative electrode material for sodium-ion batteries.

[0015] 3. The raw materials used in the preparation process of this invention are not only abundant in source, but also inexpensive, non-toxic and pollution-free. In industrial production, this greatly reduces production costs and meets the requirements of green production. At the same time, the equipment used in the preparation process is simple, the preparation process is easy to control, there are no special equipment requirements, the preparation process is simple and easy to implement, and it is relatively easy to achieve large-scale industrial production.

[0016] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0017] 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.

[0018] Figure 1 This is a topographic diagram provided in Embodiment 1 of the present invention; Figure 2 This is a morphological diagram provided for Comparative Embodiment 1 of the present invention; Figure 3 This is a charge-discharge curve provided in Embodiment 1 of the present invention; Figure 4 The charge-discharge curve is provided for Comparative Example 1 of the present invention. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0020] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0021] Example like Figures 1 to 4 As shown, the preparation method of SnSe / Fe3Se4 / rGO@NC composite material includes the following steps: Step 1: Add graphene oxide to the solution and sonicate to obtain a uniform dispersion A; Step 2: Add dispersion A to a high-pressure reactor containing tin salt and iron salt, and stir magnetically for 6-8 hours; Step 3: Add organic matter based on Step 2, and continue magnetic stirring for 2-3 hours to obtain black solution B; Step 4: Seal the high-pressure reactor and carry out a solvothermal reaction to obtain precursor powder; Step 5: Physically mix the precursor powder with selenium powder and place it in a tube furnace for calcination in an argon atmosphere to obtain SnSe / Fe3Se4 / rGO; Step 6: Disperse SnSe / Fe3Se4 / rGO uniformly in an aqueous solution containing PVP, filter, and dry to obtain SnSe / Fe3Se4 / rGO@PVP; Step 7: Place an appropriate amount of SnSe / Fe3Se4 / rGO@PVP in a tube furnace and calcine it in an argon atmosphere to obtain SnSe / Fe3Se4 / rGO@NC.

[0022] The solution described in this invention is prepared by mixing N,N-dimethylformamide and methanol in a volume ratio of 7:1, wherein the concentration of graphene oxide is 1.25 g·L⁻¹. -1 .

[0023] In this invention, the molar ratio of tin salt to iron salt is 2:1, wherein the tin salt is SnCl4∙5H2O and the iron salt is FeSO4∙7H2O.

[0024] The organic compound described in this invention is at least one of 2-methylimidazole and imidazole.

[0025] The temperature of the solvothermal reaction described in this invention is 110–160 °C.

[0026] In this invention, the precursor powder and selenium powder are physically mixed by grinding or ball milling.

[0027] The concentration of the PVP aqueous solution described in this invention is 0.02–0.05 g·L⁻¹. -1 The calcination temperature is 450–650℃, and the time is 1–3 h.

[0028] Example 1 The preparation method of the SnSe / Fe3Se4 / rGO@NC composite material includes the following steps: Step 1: Add 10 mg of graphene oxide to a mixed solution containing 7 mL of N,N-dimethylformamide and 1 mL of methanol, and sonicate for 10 min to obtain a uniform dispersion A; Step 2: Add dispersion A to a high-pressure reactor containing 27.8 mg FeSO4∙7H2O and 70.1 mg SnCl4∙5H2O, and stir magnetically for 6 h; Step 3: Add 65.6 mg of 2-methylimidazole to the mixture from Step 2, and continue stirring for 2 hours; Step 4: After sealing the high-pressure reactor, react at 120℃ for 24 hours; Step 5: Physically mix the precursor and selenium powder at a mass ratio of 2:3, and heat at a rate of 5°C / min under an Ar atmosphere. -1 Calcination at 550℃ for 2 h yielded SnSe / Fe3Se4 / rGO; Step 6: Disperse 100 mg SnSe / Fe3Se4 / rGO in 7.5 mL of distilled water, and add 5 mL of 0.025 g·L⁻¹. -1 A polyvinylpyrrolidone aqueous solution was mixed thoroughly, filtered, and dried to obtain SnSe / Fe3Se4 / rGO@PVP; Step 7: Place SnSe / Fe3Se4 / rGO@PVP into a tube furnace and heat at a rate of 5 °C / min under an Ar atmosphere. -1 Calcination at 550℃ for 2 h yielded SnSe / Fe3Se4 / rGO@NC.

[0029] Comparative Example 1 Step 1: Add 10 mg of graphene oxide to a mixed solution containing 7 mL of N,N-dimethylformamide and 1 mL of methanol, and sonicate for 10 min to obtain a uniform dispersion A; Step 2: Add dispersion A to a high-pressure reactor containing 69.5 mg FeSO4∙7H2O and 17.53 mg SnCl4∙5H2O, and stir immediately for 6 h; Step 3: Add 65.6 mg of 2-methylimidazole and continue stirring for 2 hours; Step 4: After sealing the high-pressure reactor, react at 120℃ for 24 hours; Step 5: Physically mix the precursor and sublimated Se powder at a mass ratio of 2:3, and heat at a rate of 5 °C / min under an Ar atmosphere. -1 Calcination at 550℃ for 2 h yielded SnSe / Fe3Se4 / rGO.

[0030] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. Preparation method of SnSe / Fe3Se4 / rGO@NC composite material, Its features are, Includes the following steps: Step 1: Add graphene oxide to the solution and sonicate to obtain a uniform dispersion A; Step 2: Add dispersion A to a high-pressure reactor containing tin salt and iron salt, and stir magnetically for 6-8 hours; Step 3: Add organic matter based on Step 2, and continue magnetic stirring for 2-3 hours to obtain black solution B, wherein the organic matter is at least one of 2-methylimidazole and imidazole; Step 4: Seal the high-pressure reactor and carry out a solvothermal reaction to obtain precursor powder; Step 5: Physically mix the precursor powder with selenium powder and place it in a tube furnace for calcination in an argon atmosphere to obtain SnSe / Fe3Se4 / rGO; Step 6: Disperse SnSe / Fe3Se4 / rGO uniformly in an aqueous solution containing PVP, filter, and dry to obtain SnSe / Fe3Se4 / rGO@PVP; Step 7: Place an appropriate amount of SnSe / Fe3Se4 / rGO@PVP in a tube furnace and calcine it in an argon atmosphere to obtain SnSe / Fe3Se4 / rGO@NC.

2. The method for preparing the SnSe / Fe3Se4 / rGO@NC composite material according to claim 1, characterized in that: The solution was prepared by mixing N,N-dimethylformamide and methanol in a volume ratio of 7:1, wherein the concentration of graphene oxide was 1.25 g·L⁻¹. -1 .

3. The method for preparing the SnSe / Fe3Se4 / rGO@NC composite material according to claim 1, characterized in that: The molar ratio of the tin salt to the iron salt is 2:1, wherein the tin salt is SnCl4∙5H2O and the iron salt is FeSO4∙7H2O.

4. The method for preparing the SnSe / Fe3Se4 / rGO@NC composite material according to claim 1, characterized in that: The temperature of the solvothermal reaction is 110–160 °C.

5. The method for preparing the SnSe / Fe3Se4 / rGO@NC composite material according to claim 1, characterized in that: The precursor powder and selenium powder are physically mixed by grinding or ball milling.

6. The method for preparing the SnSe / Fe3Se4 / rGO@NC composite material according to claim 1, characterized in that: The concentration of the PVP aqueous solution is 0.02–0.05 g·L⁻¹. -1 The calcination temperature is 450–650℃, and the time is 1–3 h.

7. The method for preparing the SnSe / Fe3Se4 / rGO@NC composite material according to any one of claims 1 to 6, characterized in that, Includes the following steps: Step 1: Add 10 mg of graphene oxide to a mixed solution containing 7 mL of N,N-dimethylformamide and 1 mL of methanol, and sonicate for 10 min to obtain a uniform dispersion A; Step 2: Add dispersion A to a high-pressure reactor containing 27.8 mg FeSO4∙7H2O and 70.1 mg SnCl4∙5H2O, and stir magnetically for 6 h; Step 3: Add 65.6 mg of 2-methylimidazole to the mixture from Step 2, and continue stirring for 2 hours; Step 4: After sealing the high-pressure reactor, react at 120℃ for 24 hours; Step 5: Physically mix the precursor and selenium powder at a mass ratio of 2:3, and heat at a rate of 5 °C / min under an Ar atmosphere. -1 Calcination at 550℃ for 2 h yielded SnSe / Fe3Se4 / rGO; Step 6: Disperse 100 mg SnSe / Fe3Se4 / rGO in 7.5 mL of distilled water, and add 5 mL of 0.025 g·L⁻¹. -1 A polyvinylpyrrolidone aqueous solution was mixed thoroughly, filtered, and dried to obtain SnSe / Fe3Se4 / rGO@PVP; Step 7: Place SnSe / Fe3Se4 / rGO@PVP into a tube furnace and heat at a rate of 5 °C / min under an Ar atmosphere. -1 Calcination at 550℃ for 2 h yielded SnSe / Fe3Se4 / rGO@NC.

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