Surface two-dimensional nanoflower coated tin, and preparation method and application thereof

Abstract

The application discloses two-dimensional nanoflower-coated tin and a preparation method and application thereof. The two-dimensional nanoflower-coated tin is obtained by dispersing commercial tin in water and then transferring the tin into a hydrothermal kettle to react through a hydrothermal method. The application has the advantages of simple process, low cost, good operability and repeatability, and the prepared material contains uniform two-dimensional nanoflower coating on the tin surface, can solve the problems of accelerating the conduction of lithium ions and improving the volume expansion during the charging and discharging process when the tin is used as a negative electrode material, and can be potentially applied in large scale in lithium ion batteries.

Description

Technical Field

[0001] This invention relates to a two-dimensional nanoflower-coated tin, its preparation method and application technology, belonging to the field of tin-based materials technology. Background Technology

[0002] In recent years, the extensive extraction of traditional fossil fuels, such as coal and oil, has led to increasingly serious environmental pollution problems. Furthermore, fossil fuels are gradually becoming depleted. New energy sources such as solar, geothermal, wind, and ocean energy are emerging. Lithium-ion batteries, due to their advantages such as high energy density, high voltage, long cycle stability, low self-discharge, and environmental friendliness, are widely used in various fields, including mobile electronic devices, electric vehicles, and even important sectors such as military and aerospace, becoming the mainstay of energy storage devices.

[0003] Miniaturization of electrochemical energy storage devices is a current development trend, requiring the storage of as much energy as possible within a limited volume. However, the theoretical specific capacity of commercially available graphite anodes is currently relatively low (372 mAh g⁻¹). -1 Metallic tin has a high theoretical capacity (847 mAh g). -1 Tin is a promising next-generation anode material. However, during charge and discharge, the volume expansion (>300%) caused by lithium-ion insertion and extraction can even lead to detachment from the current collector and loss of activity. Simultaneously, the slow lithium-ion kinetics severely limit its cycle stability. Currently, the most effective way to address the volume expansion of metallic tin and the rapid diffusion of lithium ions is to nanoscale tin particles. This can effectively buffer the volume expansion of Sn nanoparticles. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the problem that tin, when used as a negative electrode material of lithium-ion batteries, undergoes severe volume expansion during charging and discharging, and then pulverizes and falls off, resulting in rapid performance degradation. The present invention provides a two-dimensional nanoflower-coated tin material.

[0005] The purpose of this invention is to provide a method for preparing two-dimensional nanoflower-coated tin materials.

[0006] Another objective of this invention is to provide a two-dimensional nanoflower-coated tin material prepared by the above method.

[0007] Another objective of this invention is to provide applications of the aforementioned two-dimensional nanoflower-coated tin material.

[0008] The above-mentioned objective of this invention is achieved through the following technical solutions:

[0009] A method for preparing two-dimensional nanoflower-coated tin involves dispersing tin in water via a hydrothermal process and reacting it under hydrothermal conditions. This invention features a simple process, low cost, good repeatability, and excellent operability. The prepared material possesses a two-dimensional surface structure, which solves the problem of material pulverization and detachment caused by volume expansion of tin during charging and discharging. This method can be applied on a large scale in lithium-ion batteries.

[0010] Specifically, the preparation method of the above-mentioned two-dimensional nanoflower-coated tin includes the following steps:

[0011] A method for preparing two-dimensional nanoflowers coated with tin includes the following specific steps:

[0012] S1. Commercial tin is stirred and ultrasonically dispersed in deionized water to obtain a dispersion;

[0013] S2. Weigh the dispersion obtained in S1 and transfer it to the reaction vessel. The temperature range is 150-200℃, and the holding time is 6-48h to carry out the hydrothermal reaction. After it cools naturally, the product after the hydrothermal reaction is obtained.

[0014] S3. The product obtained from the hydrothermal reaction in S2 is filtered, washed, and freeze-dried to finally obtain a two-dimensional nanoflower-coated tin material.

[0015] In step S1, the tin particle size is 10-60 μm;

[0016] The concentration of the tin dispersion in step S1 is 1–10 mg / ml. -1 ;

[0017] Furthermore, the two-dimensional nanoflowers coated with tin prepared by the above method and their application in lithium-ion batteries are also within the scope of protection of this invention.

[0018] This invention employs a hydrothermal method, where tin particles undergo surface oxidation under high temperature and pressure to form tin oxides, which in turn form two-dimensional nanostructures on the tin particles. By controlling the time and temperature of the hydrothermal reaction, the thickness of the two-dimensional structure on the tin surface can be controlled, allowing tin to form two-dimensional nanoflowers that coat the tin particles, with the surface nanosheet size ranging from 10 to 200 nm.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] 1. The present invention prepares tin coated with two-dimensional nanoflowers, which can effectively buffer the volume change during the alloying process when tin is used as a negative electrode material of lithium-ion batteries, thereby improving the cycle life and capacity of lithium-ion batteries.

[0021] 2. This preparation process is simple, easy to implement, low in cost, and suitable for large-scale production. Attached Figure Description

[0022] Figure 1 The images show scanning electron microscope (SEM) images of the two-dimensional nanoflower-coated tin prepared in Example 1. In the images, A represents the macroscopically uniform two-dimensional sheet-like structure on the surface of micron-sized tin particles; B represents a locally magnified two-dimensional sheet-like structure on the tin surface that is clearer.

[0023] Figure 2 The image shows the X-ray diffraction pattern of the two-dimensional nanoflowers coated with tin prepared in Example 1. The standard XRD pattern of tin is shown (PDF#04-0673), and tin oxide is also present.

[0024] Figure 3 This is a comparison of the electrochemical impedance performance of the two-dimensional nanoflower-coated tin prepared in Example 1 and commercial tin when used as negative electrode materials for lithium-ion batteries.

[0025] Figure 4 The charge-discharge curves of the electrochemical cycle process when the two-dimensional nanoflower-coated tin prepared in Example 1 is used as the negative electrode material of a lithium-ion battery are shown. Detailed Implementation

[0026] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but this should not be construed as limiting the present invention. Simple modifications or substitutions made to the methods, steps, or conditions of the present invention without departing from the spirit and substance of the invention are all within the scope of the present invention; unless otherwise specified, the reagents, methods, and equipment used in the present invention are conventional reagents, methods, and equipment in this technical field.

[0027] Example 1

[0028] 1. Preparation:

[0029] S1. Commercial tin is stirred and ultrasonically dispersed in deionized water to obtain a dispersion;

[0030] S2. Weigh the dispersion obtained in S1 and transfer it to the reaction vessel. The temperature range is 150℃ and the holding time is 48h to carry out the hydrothermal reaction. After it cools naturally, the product after the hydrothermal reaction is obtained.

[0031] S3. The product obtained from the hydrothermal reaction in S2 is filtered, washed, and freeze-dried to finally obtain a two-dimensional nanoflower-coated tin material.

[0032] 2. Characterization and performance testing:

[0033] The two-dimensional nanoflowers coated with tin prepared above were characterized and their performance was tested. Figure 1 The image shows a two-dimensional nanoflower-coated tin, which reveals a distinct nanosheet structure on the tin surface, with sheet sizes ranging from approximately 20 to 200 nm. Figure 2 X-ray diffraction pattern and standard pattern of tin-coated two-dimensional nanoflowers. Figure 3The impedance performance of lithium-ion batteries for tin coated with two-dimensional nanoflowers and commercial tin is compared. Tin coated with two-dimensional nanoflowers has a significantly lower impedance than commercial tin, indicating that tin coated with two-dimensional nanoflowers has superior kinetic performance. Figure 4 This lithium-ion battery, featuring two-dimensional nanoflower-coated tin, achieved a first-cycle discharge capacity of 1380.4 mAh g. -1 The coulomb efficiency reached 78.1% in the first cycle, and the capacity remained at 741.9 mAh g after 200 cycles. -1 The good cycling stability indicates that the two-dimensional nanoflower-coated tin structure is beneficial for buffering the volume change of tin during charging and discharging and improving the kinetic performance of lithium ions, thereby avoiding material pulverization and accelerating lithium ion conduction.

[0034] Example 2

[0035] 1. Preparation:

[0036] 1. Preparation:

[0037] S1. Commercial tin is stirred and ultrasonically dispersed in deionized water to obtain a dispersion;

[0038] S2. Weigh the dispersion obtained in S1 and transfer it to the reaction vessel. The temperature range is 160℃ and the holding time is 36h to carry out the hydrothermal reaction. After it cools naturally, the product after the hydrothermal reaction is obtained.

[0039] S3. The product obtained from the hydrothermal reaction in S2 is filtered, washed, and freeze-dried to finally obtain a two-dimensional nanoflower-coated tin material.

[0040] Example 3

[0041] 1. Preparation:

[0042] 1. Preparation:

[0043] S1. Commercial tin is stirred and ultrasonically dispersed in deionized water to obtain a dispersion;

[0044] S2. Weigh the dispersion obtained in S1 and transfer it to the reaction vessel. The temperature range is 180℃ and the holding time is 24h to carry out the hydrothermal reaction. After it cools naturally, the product after the hydrothermal reaction is obtained.

[0045] S3. The product obtained from the hydrothermal reaction in S2 is filtered, washed, and freeze-dried to finally obtain a two-dimensional nanoflower-coated tin material.

[0046] Example 4

[0047] 1. Preparation:

[0048] 1. Preparation:

[0049] S1. Commercial tin is stirred and ultrasonically dispersed in deionized water to obtain a dispersion;

[0050] S2. Weigh the dispersion obtained in S1 and transfer it to the reaction vessel. The temperature range is 200℃ and the holding time is 6h. Perform the hydrothermal reaction and let it cool naturally to obtain the product after the hydrothermal reaction.

[0051] S3. The product obtained from the hydrothermal reaction in S2 is filtered, washed, and freeze-dried to finally obtain a two-dimensional nanoflower-coated tin material.

[0052] The above embodiments are merely illustrative examples to clearly illustrate the present invention and are not intended to limit the implementation of the invention. Those skilled in the art can make other variations based on the above description. It is neither necessary nor possible to exhaustively describe all possible implementations. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for preparing two-dimensional nanoflower-coated tin, characterized in that, The specific steps include the following: S1. Commercial tin was stirred and ultrasonically dispersed in deionized water to obtain a dispersion; the tin particle size was 10-60 micrometers; the concentration of the tin dispersion was 1-10 mg / ml. -1 ; S2. Weigh the dispersion obtained in S1 and transfer it to a reaction vessel. The temperature range is 150~200 ℃, and the holding time is 6~48h to carry out the hydrothermal reaction. After natural cooling, the product after the hydrothermal reaction is obtained. S3. The product obtained from the hydrothermal reaction in S2 is filtered, washed, and freeze-dried to finally obtain a two-dimensional nanoflower-coated tin material.

2. A two-dimensional nanoflower-coated tin material prepared by the preparation method of two-dimensional nanoflower-coated tin according to claim 1, characterized in that, Using a hydrothermal method, tin particles undergo surface oxidation under high temperature and pressure to form tin oxides, which in turn form two-dimensional nanostructures on the tin particles. By controlling the time and temperature of the hydrothermal reaction, the thickness of the two-dimensional structure on the tin surface can be controlled, so that tin forms two-dimensional nanoflowers that coat the tin particles, with the surface nanosheet size ranging from 10 to 200 nm.

3. The application of the two-dimensional nanoflower-coated tin material according to claim 1 in the field of lithium-ion batteries.

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