Preparation method of 3D graphene loaded tin oxide composite material

Abstract

The invention discloses a preparation method of a 3D graphene-loaded tin oxide composite material. The preparation method comprises the following steps: preparing a precursor solution from graphene oxide, tin tetrachloride pentahydrate and ascorbic acid; dropwise adding a lauryl sodium sulfate solution into the precursor solution, and fully mixing to obtain a mixed solution; transferring the mixed solution into a glass bottle, and sealing and heating to promote the self-loading process of the solution; performing freeze thawing / 80 DEG C thermal reduction treatment on the preformed sample to form a preliminary composite material of tin oxide and graphene; repeatedly washing the sample subjected to thermal reduction by using ethanol to remove residual impurities, and then carrying out drying treatment; and carrying out annealing heat treatment on the dried sample in a nitrogen atmosphere to obtain the 3D graphene-loaded tin oxide composite material. The preparation method of the 3D graphene loaded tin oxide composite material provided by the invention is simpler in preparation process, lower in cost and suitable for large-scale industrial production.

Description

Technical Field

[0001] This invention relates to the field of sodium-ion battery anode materials, and more particularly to a method for preparing a 3D graphene-supported tin oxide composite material. Background Technology

[0002] Against the backdrop of continuous global industrial progress, exploring sustainable energy storage technologies has become an important focus for researchers. Lithium-ion batteries have demonstrated outstanding performance in the energy storage field and have attracted widespread attention. However, considering the high cost, limited reserves, and potential environmental impact of lithium resources, their sustainability and long-term feasibility have drawn significant attention. Therefore, developing environmentally friendly and resource-rich new battery materials is of great importance.

[0003] Sodium-ion batteries have attracted increasing attention in recent decades due to the replacement of lithium-ion batteries with abundant sodium ions. However, because sodium ions have a large ionic radius, they cannot be reversibly stored in the layers of graphite anodes like lithium ions. Among materials with good sodium storage performance, tin oxide, which combines conversion and alloying mechanisms, has become a focus of research on sodium-ion battery anode materials due to its high sodium ion storage capacity (1378 mAh g⁻¹). However, tin oxide as an anode material undergoes significant volume expansion during alloying, resulting in poor cycle stability. In addition, tin oxide itself has poor conductivity, requiring nano-sizing to control its morphology and size, or composite with highly conductive carbon materials. Graphene is a common carbon-based material that can be used to improve the low conductivity of tin oxide and the rate and cycle performance of anode materials that experience repeated volume changes during charge and discharge.

[0004] Chinese patent application CN105609713A discloses a method for preparing irradiated tin dioxide / graphene aerogel nanomaterials for use as battery anode materials. This material is an irradiated tin dioxide / graphene aerogel nanocomposite material. Tin spheres are prepared via a redox method, and graphene oxide is prepared via a modified Hummers method. The two are then reacted using a hydrothermal method to form an aerogel, which is finally modified by electron beam irradiation. This material exhibits excellent electrochemical performance, with an initial discharge capacity as high as 2060 mAh·g. -1The technology exhibits good stability in cyclic testing. However, it involves a multi-step synthesis process, including redox, hydrothermal reaction, and electron beam irradiation, which is energy-intensive, requires highly skilled operators, increases the complexity of preparation, and involves hazardous chemicals such as concentrated sulfuric acid, posing a high operational risk and requiring strict safety measures. Chinese patent application CN110649258A discloses a method for preparing a three-dimensional porous tin oxide-graphene composite electrode material. This method involves using a precursor solution of tin tetrachloride pentahydrate and graphene oxide, followed by preheating at 80°C, a long-term (24-48h) hydrothermal reaction at 180°C, and subsequent freeze-drying and calcination to obtain the three-dimensional porous tin oxide-graphene composite electrode material. This composite material aims to improve the conductivity of tin dioxide and suppress its volume expansion during charge and discharge processes to improve the high-rate performance of the battery. However, this method involves specific high-temperature hydrothermal reaction equipment and freeze-drying equipment, and the overall process is complex and energy-intensive. These factors may weaken the competitiveness of this technology in industrial-scale applications. Summary of the Invention

[0005] In view of the aforementioned shortcomings of the prior art, the technical problem to be solved by the present invention is that the existing nanocomposite material preparation technologies suffer from complex preparation processes, high reaction temperatures, high costs, and large energy consumption, which limit their application in industrial production. The present invention provides a method for preparing 3D graphene-supported tin oxide composite materials, which has a simpler preparation process, lower costs, and is suitable for large-scale industrial production.

[0006] To achieve the above objectives, the present invention provides a method for preparing a 3D graphene-supported tin oxide composite material, comprising the following steps:

[0007] A precursor solution was prepared using graphene oxide, tin tetrachloride pentahydrate, and ascorbic acid.

[0008] Sodium dodecyl sulfate solution was added dropwise to the precursor solution and mixed thoroughly to obtain a mixed solution;

[0009] The mixed solution is transferred to a glass bottle, sealed and heated to promote the self-filling process of the solution and form a pre-formed structure;

[0010] The pre-formed sample stars were subjected to cryogenic reduction treatment to form a preliminary composite material of tin oxide and graphene.

[0011] The sample after thermal reduction was repeatedly washed with ethanol to remove residual impurities, and then dried.

[0012] The dried sample was annealed in a nitrogen atmosphere to obtain a 3D graphene-supported tin oxide composite material.

[0013] Furthermore, a precursor solution was prepared using graphene oxide, tin tetrachloride pentahydrate, and ascorbic acid. Specifically, 15-20% by mass of graphene oxide, 35-40% by mass of tin tetrachloride pentahydrate SnCl4·5H2O, and 40-50% by mass of ascorbic acid were weighed and added to deionized water. The components were then uniformly dispersed by ultrasonic treatment to form a homogeneous precursor solution.

[0014] Furthermore, the graphene oxide was prepared in advance using a modified Hummer method.

[0015] Furthermore, the purity of tin tetrachloride pentahydrate SnCl4·5H2O was set to 99.9%.

[0016] Furthermore, the purity of ascorbic acid was set to 99.0%.

[0017] Further, the sodium dodecyl sulfate solution is added dropwise to the precursor solution and thoroughly mixed to obtain a mixed solution. Specifically, 70-100 mg of sodium dodecyl sulfate solution is weighed and added dropwise to the precursor solution, and the mixture is stirred vigorously at room temperature for 5-20 minutes to promote thorough mixing of the various components, thereby obtaining a mixed solution.

[0018] Furthermore, the mixed solution is transferred to a glass bottle and sealed and heated to promote the self-filling process of the solution and form a pre-formed structure. Specifically, the mixed solution is transferred to a glass bottle and the bottle mouth is sealed. Then, the glass bottle is placed in an oven at 80~100 ℃ and heated for 50~80 min to promote the self-filling process of the solution and form a pre-formed structure, which is a 3D columnar hydrogel.

[0019] Furthermore, the pre-formed sample undergoes a freeze-heat reduction treatment to form a preliminary composite material of tin oxide and graphene. Specifically, the pre-formed sample is transferred to a freezer at -20 to -10°C and frozen for 20 to 30 hours, and then thermally reduced in an oven at 70 to 90°C for 5 to 7 hours to form a preliminary composite material of tin oxide and graphene, which is a 3D graphene aerogel.

[0020] Furthermore, the thermally reduced sample is repeatedly washed with ethanol to remove residual impurities, and then dried. Specifically, the thermally reduced sample is repeatedly washed with ethanol to remove residual impurities, and then dried at 50~70℃ for 20~30 h to ensure the purity and dryness of the sample.

[0021] Furthermore, the dried sample is annealed in a nitrogen atmosphere to obtain a 3D graphene-supported tin oxide composite material. Specifically, the dried sample is placed in a tube furnace and heated to 450~550℃ at a heating rate of 5℃ / min in a nitrogen atmosphere, and held for 2~3h to improve the stability of the material. The sample is then cooled and removed to obtain the 3D graphene-supported tin oxide composite material, which is anchored in the 3D graphene network.

[0022] Technical effect

[0023] This invention provides a method for preparing a 3D graphene-supported tin oxide composite material. The entire preparation process is mild and energy-efficient. Through simplified steps and low-cost raw materials, it achieves efficient composite formation of tin oxide and graphene. Utilizing the high conductivity and porous structure of the 3D graphene network, the conductivity and structural stability of tin oxide are effectively improved. The method provided by this invention avoids the use of hazardous chemicals and expensive equipment, reducing production costs and operational risks, and providing a safer, more economical, and environmentally friendly solution for the development of sodium-ion battery anode materials.

[0024] The following will further explain the concept, specific structure, and technical effects of the present invention in conjunction with the accompanying drawings, so as to fully understand the purpose, features, and effects of the present invention. Attached Figure Description

[0025] Figure 1 This is a schematic flowchart of a preferred embodiment of the present invention for preparing a 3D graphene-supported tin oxide composite material.

[0026] Figure 2 This is an XRD pattern of a method for preparing a 3D graphene-supported tin oxide composite material according to a preferred embodiment of the present invention.

[0027] Figure 3 This is a SEM image of a method for preparing a 3D graphene-supported tin oxide composite material according to a preferred embodiment of the present invention.

[0028] Figure 4 This is a schematic diagram showing the rate performance of a 3D graphene-supported tin oxide composite material at different current densities, according to a preferred embodiment of the present invention. Detailed Implementation

[0029] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0030] In the following description, specific details, such as particular internal procedures and techniques, are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of the invention. However, those skilled in the art will appreciate that the invention may be practiced in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted so as not to obscure the description of the invention with unnecessary detail.

[0031] This invention provides a method for preparing a 3D graphene-supported tin oxide composite material, comprising the following steps:

[0032] Step 1: A precursor solution is prepared using graphene oxide, tin tetrachloride pentahydrate, and ascorbic acid. Specifically, 15-20% (by mass) of graphene oxide, 35-40% (by mass) of tin tetrachloride pentahydrate (SnCl4·5H2O), and 40-50% (by mass) of ascorbic acid are added to deionized water. The mixture is then ultrasonically treated to ensure uniform dispersion of the components, forming a homogeneous precursor solution. The graphene oxide is prepared beforehand using a modified Hummer method; the purity of tin tetrachloride pentahydrate (SnCl4·5H2O) is set to 99.9%; and the purity of ascorbic acid is set to 99.0%.

[0033] Step 2: Add sodium dodecyl sulfate solution dropwise to the precursor solution and mix thoroughly to obtain a mixed solution; specifically, weigh 70-100 mg of sodium dodecyl sulfate solution and add it dropwise to the precursor solution, and stir vigorously at room temperature for 5-20 min to promote thorough mixing of various components, thereby obtaining a mixed solution.

[0034] Step 3: Transfer the mixed solution to a glass bottle, seal and heat it to promote the self-filling process of the solution and form a pre-formed structure; specifically, this includes transferring the mixed solution to a glass bottle, sealing the bottle opening, and then placing the glass bottle in an oven at 80~100℃ for 50~80 minutes to promote the self-filling process of the solution and form a pre-formed structure, which is a 3D columnar hydrogel.

[0035] Step 4 involves freezing and thermally reducing the preformed sample to form a preliminary composite material of tin oxide and graphene. Specifically, the preformed sample is transferred to a freezer at -20 to -10°C for 20 to 30 hours and then thermally reduced in an oven at 70 to 90°C for 5 to 7 hours to form a preliminary composite material of tin oxide and graphene, which is a 3D graphene aerogel.

[0036] Step 5: Wash the thermally reduced sample repeatedly with ethanol to remove residual impurities, and then dry it. Specifically, wash the thermally reduced sample repeatedly with ethanol to remove residual impurities, and then dry it at 50~70℃ for 20~30 h to ensure the purity and dryness of the sample.

[0037] Step 6: The dried sample is annealed in a nitrogen atmosphere to obtain a 3D graphene-supported tin oxide composite material. Specifically, the dried sample is placed in a tube furnace and heated to 450~550℃ at a heating rate of 5℃ / min under a nitrogen atmosphere, and held for 2~3 hours to improve the stability of the material. The sample is then cooled and removed to obtain the 3D graphene-supported tin oxide composite material, in which the tin oxide composite material is anchored in the 3D graphene network.

[0038] The following specific embodiments will illustrate a method for preparing a 3D graphene-supported tin oxide composite material according to the present invention.

[0039] Example 1:

[0040] This embodiment provides a method for preparing 3D graphene-supported tin oxide composite materials, which is a simple and mild method for preparing self-assembled tin oxide / 3D graphene aerogel nanocomposite materials (process flow as follows). Figure 1 (As shown), including the following steps:

[0041] Step 1: Preparation of precursor solution

[0042] 32 mg of graphene oxide, 64 mg of tin tetrachloride pentahydrate (SnCl4·5H2O), and 80 mg of ascorbic acid were weighed and added to deionized water. The mixture was then sonicated to ensure uniform dispersion of the components, forming a homogeneous precursor solution. The graphene oxide was prepared beforehand using a modified Hummer method. The purity of tin tetrachloride pentahydrate (SnCl4·5H2O) was 99.9%. The purity of ascorbic acid was 99.0%. The solute mass percentage of the sodium dodecyl sulfate solution was 5.0%.

[0043] Step 2: Mixing Process

[0044] Weigh 80 mg of sodium dodecyl sulfate solution and add it dropwise to the precursor solution, and stir vigorously at room temperature for 10 min to promote thorough mixing of the various components.

[0045] Step 3: Self-assembly preforming

[0046] The mixed solution was transferred to a glass bottle and the bottle was sealed. The glass bottle was then placed in an oven at 90 °C and heated for 60 min to promote the self-filling process of the solution and form a pre-formed structure.

[0047] Step 4: Freeze-heat reduction treatment

[0048] The preformed sample was transferred to a freezer at -20 °C and frozen for 20 h, and then thermally reduced in an oven at 80 °C for 6 h to form a preliminary composite material of tin oxide and graphene.

[0049] Step 5: Washing and Drying

[0050] The thermally reduced sample was repeatedly washed with ethanol to remove any possible residual impurities, and then dried at 60 °C for 24 h to ensure the purity and dryness of the sample.

[0051] Step 6: Annealing heat treatment

[0052] The dried sample was placed in a tube furnace and heated to 500 °C at a heating rate of 5 °C / min under a nitrogen atmosphere, and held for 2 h to improve the stability of the material. The sample was then cooled and removed, yielding a tin oxide composite material anchored to a 3D graphene network. The XRD and SEM images of the obtained product are shown below. Figure 2 and 3 As shown in the figure. Phase analysis by XRD, compared with the PDF card, confirms that this method successfully synthesized pure tin dioxide material. The sample morphology is as follows. Figure 3 SEM images show that tin dioxide particles are relatively evenly distributed in the wrinkled graphene sheet region. The addition of tin dioxide particles can suppress the excessive stacking of graphene sheets to a certain extent, while the porous graphene network, as a carrier for tin dioxide particles, provides a rich conductive network for tin dioxide and suppresses its volume expansion during cycling to a certain extent.

[0053] Example 2:

[0054] This embodiment provides a method for preparing 3D graphene-supported tin oxide composite material, including the following steps:

[0055] Step 1: Preparation of precursor solution

[0056] 40 mg of graphene oxide, 80 mg of tin tetrachloride pentahydrate (SnCl4·5H2O), and 80 mg of ascorbic acid were weighed and added to deionized water. The mixture was then sonicated to ensure uniform dispersion of the components, forming a homogeneous precursor solution. The graphene oxide was prepared beforehand using a modified Hummer method. The purity of tin tetrachloride pentahydrate (SnCl4·5H2O) was 99.9%. The purity of ascorbic acid was 99.0%. The solute mass percentage of the sodium dodecyl sulfate solution was 5.0%.

[0057] Step 2: Mixing Process

[0058] Weigh 100 mg of sodium dodecyl sulfate solution and add it dropwise to the precursor solution, and stir vigorously at room temperature for 15 min to promote thorough mixing of the various components.

[0059] Step 3: Self-assembly preforming

[0060] The mixed solution was transferred to a glass bottle and the bottle was sealed. The glass bottle was then placed in an oven at 100 °C and heated for 80 min to promote the self-filling process of the solution and form a pre-formed structure.

[0061] Step 4: Freeze-heat reduction treatment

[0062] The preformed sample was transferred to a freezer at -15 °C and frozen for 30 h, and then thermally reduced in an oven at 90 °C for 5 h to form a preliminary composite material of tin oxide and graphene.

[0063] Step 5: Washing and Drying

[0064] The thermally reduced sample was repeatedly washed with ethanol to remove any remaining impurities, and then dried at 70 °C for 20 h to ensure the purity and dryness of the sample.

[0065] Step 6: High-temperature heat treatment

[0066] The dried sample was placed in a tube furnace and heated to 450 °C at a heating rate of 5 °C / min under a nitrogen atmosphere and held for 3 h to improve the stability of the material. The sample was then cooled and removed to obtain a tin oxide composite material anchored in a 3D graphene network.

[0067] Test example:

[0068] To verify the electrochemical performance of 3D graphene-supported tin oxide composite material as a negative electrode material for sodium-ion batteries, this study assembled it into a CR 2032 coin cell. In the experiment, a self-made pure sodium sheet was used as the counter electrode, while the working electrode was prepared by mixing active material, Super P conductive agent, and polyvinylidene fluoride (PVDF) binder in a mass ratio of 8:1:1. A suitable amount of N-methyl-2-pyrrolidone (NMP) was added as a solvent to form a homogeneous slurry, which was then coated onto copper foil and dried in a vacuum oven at 100 °C to form an electrode sheet. The dried electrode sheet was cut into 12 mm diameter discs with a loaded mass controlled between 0.8 and 1.2 mg. Whatman glass microfiber filters (Grade GF / A) were used as the battery separator. The electrolyte was prepared by mixing 1M NaClO4 and 5 wt% fluoroethylene carbonate (FEC) additive in a mixed solvent of ethylene carbonate (EC) and dimethyl carbonate (DMC) (volume ratio 1:1). The battery assembly process was carried out in an argon-filled glove box, with the water and oxygen content in the environment strictly controlled to not exceed 0.01 ppm.

[0069] Rate performance was tested using current densities of 0.1, 0.2, 0.5, 1, and 2 A / g, and within a voltage charge-discharge range of 0.01–3 A / g. Figure 4 The 3D graphene-supported tin oxide composite material prepared in this invention exhibits excellent sodium storage and cycling performance, demonstrating practical value. Tin dioxide is supported by in-situ generated 3D graphene aerogel, with tin dioxide particles evenly distributed within the wrinkled graphene sheet regions. The material possesses a rich mesoporous structure, ensuring electrolyte wetting. The addition of tin dioxide particles can, to some extent, inhibit excessive stacking of graphene sheets, while the porous graphene network, acting as a carrier for the tin dioxide particles, provides a rich conductive network and, to some extent, suppresses volume expansion during cycling. These structural characteristics form the basis for its superior performance.

[0070] Specific performance is as follows Figure 4 As shown, the rate performance test results of the assembled battery are as follows: at a current of 0.1 A / g, the capacity exceeds 200, and even at a high current of 2 A / g, the capacity is still close to 100, which exceeds the performance of ordinary carbon-based materials.

[0071] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A method for preparing a 3D graphene supported tin oxide composite material, characterized in that, The method comprises the following steps: A precursor solution is prepared from graphene oxide, tin tetrachloride pentahydrate and ascorbic acid. A sodium dodecyl sulfate solution is added dropwise to the precursor solution for thorough mixing to obtain a mixed solution. The mixed solution is transferred to a glass bottle and sealed for heating to promote the self-assembly process of the solution and form a preformed structure. The preformed sample is subjected to freeze-thaw reduction treatment to form a preliminary composite material of tin oxide and graphene. The sample after the heat reduction is repeatedly washed with ethanol to remove residual impurities and then subjected to drying treatment. The dried sample is subjected to annealing heat treatment in a nitrogen atmosphere to obtain a 3D graphene-loaded tin oxide composite material.

2. The method for preparing a 3D graphene-supported tin oxide composite material as described in claim 1, characterized in that, A precursor solution is prepared from graphene oxide, tin tetrachloride pentahydrate and ascorbic acid, specifically, 15-20% of graphene oxide and 35-40% of tin tetrachloride pentahydrate SnCl4·5H2O and 40-50% of ascorbic acid are weighed and added to deionized water, and various components are uniformly dispersed by ultrasonic treatment to form a uniform precursor solution.

3. The method for preparing a 3D graphene-supported tin oxide composite material as described in claim 2, characterized in that, The graphene oxide is prepared in advance using a modified Hummer method.

4. The method for preparing a 3D graphene-supported tin oxide composite material as described in claim 2, characterized in that, The purity of the tin tetrachloride pentahydrate SnCl4·5H2O is set to 99.9%.

5. The method for preparing a 3D graphene-supported tin oxide composite material as described in claim 2, characterized in that, The purity of the ascorbic acid is set to 99.0%.

6. The method for preparing a 3D graphene-supported tin oxide composite material as described in claim 1, characterized in that, A sodium dodecyl sulfate solution is added dropwise to the precursor solution for thorough mixing to obtain a mixed solution, specifically, 70-100 mg of a sodium dodecyl sulfate solution is added dropwise to the precursor solution, and the mixture is stirred vigorously at room temperature for 5-20 min to promote the thorough mixing of various components, thereby obtaining a mixed solution.

7. The method for preparing a 3D graphene-supported tin oxide composite material as described in claim 1, characterized in that, The mixed solution is transferred to a glass bottle and sealed for heating to promote the self-assembly process of the solution and form a preformed structure, specifically, the mixed solution is transferred to a glass bottle, the bottle opening is sealed, and the glass bottle is placed in an oven at 80-100 ℃ for heating for 50-80 min to promote the self-assembly process of the solution and form a preformed structure, which is a 3D columnar hydrogel.

8. The method for preparing a 3D graphene-supported tin oxide composite material as described in claim 1, characterized in that, The preformed sample is subjected to freeze-thaw reduction treatment to form a preliminary composite material of tin oxide and graphene, specifically, the preformed sample is transferred to a refrigerator at -20--10 ℃ for freezing for 20-30 h, and then subjected to heat reduction in an oven at 70-90 ℃ for 5-7 h to form a preliminary composite material of tin oxide and graphene, which is a 3D graphene aerogel.

9. The method for preparing a 3D graphene-supported tin oxide composite material as described in claim 1, characterized in that, The sample after the heat reduction is repeatedly washed with ethanol to remove residual impurities and then subjected to drying treatment, specifically, the sample after the heat reduction is repeatedly washed with ethanol to remove residual impurities, and then dried in an environment at 50-70 ℃ for 20-30 h to ensure the purity and dryness of the sample.

10. The method for preparing a 3D graphene-supported tin oxide composite material as described in claim 1, characterized in that, The dried sample is annealed and heat treated in a nitrogen atmosphere to obtain a 3D graphene loaded tin oxide composite material, specifically including placing the dried sample in a tube furnace, heating to 450-550 DEG C at a heating rate of 5 DEG C / min under a nitrogen atmosphere, and keeping for 2-3 h to improve the stability of the material, and then cooling and taking out the sample, to obtain a 3D graphene loaded tin oxide composite material, the tin oxide composite material being anchored in the 3D graphene network.

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