Oxygen-sulfur double-vacancy modified SnO2 / SnS2 / C nano material as well as preparation method and application thereof

Abstract

The invention discloses an oxygen-sulfur double-vacancy modified SnO2 / SnS2 / C nano material as well as a preparation method and application thereof, and belongs to the technical field of electrode materials. The preparation method comprises the following steps: mixing a structure regulating agent with tin salt, dropwise adding alkali liquor, stirring, and carrying out suction filtration to obtain Sn6O4 (OH) 4; the preparation method comprises the following steps: adding glucose and polyvinylpyrrolidone into distilled water, stirring to form a uniform solution, adding Sn6O4 (OH) 4 into the uniform solution, stirring, and carrying out ultrasonic and hydrothermal reaction to obtain SnO2 / glucose; and calcining the SnO2 / glucose and a sulfur source in an inert atmosphere to obtain the SnO2 / SnS2 / C nano material modified by oxygen and sulfur double vacancies. The SnO2 / SnS2 / C disclosed by the invention is used for a lithium / sodium ion battery negative electrode, can effectively relieve volume expansion of tin-based oxysulfide and improve the conductivity of an electrode material, and shows high charge-discharge specific capacity, excellent rate capability and high-rate long-cycle stability.

Description

Technical Field

[0001] The present invention relates to the technical field of electrode materials, and particularly relates to an oxygen-sulfur double-vacancy modified SnO2 / SnS2 / C nanomaterial, a preparation method thereof, and an application thereof. Background Art

[0002] The birth of secondary batteries has greatly reduced the global dependence on fossil fuels. Among them, lithium-ion batteries (LIBs) have profoundly changed the human lifestyle with their wide applications and played an extremely important role in promoting the process of green and sustainable development. However, the reserves of lithium resources are limited to a certain extent. Under this background, sodium-ion batteries (SIBs) have become a powerful supplement to lithium-ion batteries due to their rich reserves. Graphite has excellent electrical conductivity and a high specific surface area, which makes it widely concerned in lithium-ion batteries and sodium-ion batteries and become a commonly used candidate anode material for such batteries. However, with the development of society, the demand for high energy density is increasing day by day, and the shortcomings of current graphite-based anode materials are becoming more and more obvious. Its theoretical capacity is only 372 mA h g -1 , which is difficult to meet the continuously improving performance requirements, and there is an urgent need for new breakthroughs.

[0003] Tin-based (Sn) electrode materials have attracted the attention of many researchers due to their excellent energy storage potential and have become the focus of research in the field of anode materials for lithium-ion batteries and sodium-ion batteries. However, during the charge and discharge cycle process, such electrode materials will experience problems such as large volume changes and rapid capacity decay, which seriously hinder their transition from the laboratory to large-scale commercial applications. As an important branch of tin-based materials, tin-based oxides have been favored by many researchers and become the object of key exploration due to advantages such as high theoretical capacity, abundant resources, and environmental friendliness. Research has found that SnO2, as a lithium / sodium storage anode, has a relatively high capacity. However, currently, how to design and prepare SnO2-based electrode materials that simultaneously possess high rate performance and long-term cycle stability and are applicable to both lithium / sodium storage remains an urgent problem to be solved. The patent with the application number CN108539136A discloses a preparation method of tin sulfide / nitrogen-doped carbon composite flower balls and their application in the anode of lithium-ion batteries. The patent with the application number CN109935804A discloses a long-life tin sulfide anode material and its preparation method. The patent with the application number CN114804190A discloses a method for size homogenization of SnO2 / SnS2 flower-shaped micron-sized particles. The patent with the application number CN114988419A discloses a SiO2 / SnSe / C nanosphere and its preparation method. The above methods improve the energy storage performance of tin-based materials by element doping or by compounding tin oxide with other selenides and oxides. However, there is no report on improving the energy storage performance by defect treatment of tin-based materials. Optimizing and modifying the internal structure of tin-based materials through defect engineering is of crucial significance for improving the electrochemical performance of electrode materials. And how to delicately construct a reasonable defect structure to ensure stable cycle performance while achieving high capacity for electrode materials is a problem that needs to be solved. Summary of the Invention

[0004] Aiming at the above-mentioned existing technologies, the purpose of the present invention is to provide an oxygen and sulfur dual-vacancy modified SnO2 / SnS2 / C nanomaterial, its preparation method and application. The present invention uses a simple hydrothermal method to prepare a glucose-coated tin oxide nanosphere (SnO2 / glucose) composite material, and then uses sublimed sulfur as a sulfur source and calcines it under the protection of an inert gas to obtain a carbon-coated oxygen and sulfur dual-vacancy modified tin dioxide composite tin disulfide nanosphere (SnO2 / SnS2 / C) composite material. The nanomaterial obtained by the present invention is used as the anode of lithium / sodium ion batteries, which can effectively alleviate the volume expansion of tin-based oxysulfides, improve the conductivity of electrode materials, and exhibit high charge and discharge specific capacity, excellent rate performance, and long cycle stability at high rates.

[0005] To achieve the above purpose, the present invention adopts the following technical solutions: In the first aspect of the present invention, a preparation method of an oxygen and sulfur dual-vacancy modified SnO2 / SnS2 / C nanomaterial is provided, including the following steps: (1) Mix a structure regulator with a tin salt, then dropwise add an alkali solution and stir. After suction filtration, a precipitate is obtained. The precipitate is dried to obtain tin oxide nanoparticles with an octahedral structure, namely Sn6O4(OH)4; (2) Add glucose and polyvinylpyrrolidone to distilled water, stir to form a homogeneous solution. Add Sn6O4(OH)4 to the homogeneous solution and stir, then perform ultrasonic treatment, and then carry out a hydrothermal reaction. After washing and drying, a glucose-coated tin oxide nanoflower sphere is obtained, namely SnO2 / glucose; (3) Mix SnO2 / glucose with a sulfur source, and calcine in an inert atmosphere. After cooling, an oxygen and sulfur dual-vacancy modified SnO2 / SnS2 / C nanomaterial is obtained.

[0006] Preferably, in step (1), the structure regulator is ethylenediamine or ethylene glycol; the tin salt is SnCl2•2H2O or SnCl4•5H2O; the alkali solution is a NaOH solution with a concentration of 0.12 mol / L to 0.17 mol / L.

[0007] Preferably, in step (1), the stirring time is 30 to 120 min.

[0008] Preferably, in step (2), the mass ratio of glucose, polyvinylpyrrolidone and Sn6O4(OH)4 is 3 to 5: 2 to 5: 1 to 3; the concentration of glucose in the homogeneous solution is 0.01 g / mL.

[0009] Preferably, in step (2), the stirring time is 20 min; the power of the ultrasonic treatment is 400 W, and the ultrasonic treatment time is 60 min; the temperature of the hydrothermal reaction is 150 to 200 °C, and the hydrothermal reaction time is 4 to 8 h.

[0010] Preferably, in step (3), the sulfur source is sulfur powder, thioacetamide or sodium hydrosulfide; the mass ratio of SnO2 / glucose and the sulfur source is 3: 2; the inert atmosphere is argon or nitrogen.

[0011] Preferably, in step (3), the heating rate of the calcination is 2 to 5 °C / min, the calcination temperature is 350 to 550 °C, and the calcination time is 1 to 3 h.

[0012] In the second aspect of the present invention, an oxygen and sulfur dual-vacancy modified SnO2 / SnS2 / C nanomaterial obtained by the above preparation method is provided. In the oxygen and sulfur dual-vacancy modified SnO2 / SnS2 / C nanomaterial, SnO2 has oxygen vacancies and SnS2 has sulfur vacancies.

[0013] The oxygen-sulfur double-vacancy modified SnO2 / SnS2 / C nanomaterial has a porous hollow nanospherical flower structure with a size of 500 nm to 2 μm.

[0014] In the third aspect of the present invention, there is provided an application of the oxygen-sulfur double-vacancy modified SnO2 / SnS2 / C nanomaterial in the preparation of a sodium-ion battery or a lithium-ion battery.

[0015] Preferably, the application is that the oxygen-sulfur double-vacancy modified SnO2 / SnS2 / C nanomaterial is used as an anode material to improve the specific capacity, cycle stability and rate performance of a sodium-ion battery or a lithium-ion battery.

[0016] Advantages of the present invention: (1) Through a novel preparation method, the present invention innovatively utilizes the self-assembly reaction of glucose-induced octahedral Sn6O4(OH)4 to obtain a SnO2 / glucose nanospherical flower composite material with a three-dimensional hollow structure. Using this as a precursor for sulfidation modification treatment, by regulating the material ratio of the precursor to the sulfur source, the simultaneous introduction of oxygen vacancies and sulfur vacancies can be achieved, and the SnO2-SnS2 heterostructure can be constructed synchronously. The finally obtained SnO2 / SnS2 / C has regular size and uniform distribution. The unique hollow nanospherical flower structure can relieve the volume expansion during the energy storage process and provide an ion transport channel, enabling the electrode material to have excellent rate performance and long cycle performance.

[0017] (2) The oxygen-sulfur double vacancies and SnO2-SnS2 heterostructure contained in the SnO2 / SnS2 / C of the present invention greatly increase the active sites of the electrode material. At the same time, it can effectively relieve the volume expansion of the electrode material during the energy storage process, enhance the structural stability of the electrode material, and the three-dimensional hollow nanosphere structure can synergistically greatly improve the energy storage performance of the electrode material. It is expected to achieve a large rate and long cycle life of lithium / sodium-ion batteries. Description of the Drawings

[0018] Figure 1 : (a) Morphology of the SnO2 / glucose composite material prepared by reacting K2SnO3•3H2O as a tin source with glucose, (b) Morphology of the SnO2 / glucose composite material prepared by reacting SnCl2•2H2O as a tin source with glucose; Figure 2 : (a) Morphology structure diagram of the hydrothermal reaction of Sn6O4(OH)4 for 6 hours without adding glucose as a carbon source; (b) Morphology structure diagram of the hydrothermal reaction of Sn6O4(OH)4 with graphene as a carbon source for 6 hours; (c) Morphology structure diagram of the hydrothermal reaction of Sn6O4(OH)4 with sucrose as a carbon source for 6 hours; Figure 3: XRD patterns of SnO2 / C, SnO2 / SnS2 / C, and SnS2 / C nanocomposites; Figure 4 : Microscopic morphologies and structures of SnO2 / glucose, SnO2 / C, SnO2 / SnS2 / C, and SnS2 / C nanocomposites; where (a) SEM morphology of SnO2 / glucose, (b) SEM morphology of SnO2 / C, (c) SEM morphology of SnO2 / SnS2 / C, (d) SEM morphology of SnS2 / C composite, (e) TEM image of SnO2 / SnS2 / C composite, (f) high-resolution TEM image of SnO2 / SnS2 / C composite; Figure 5 : Elemental energy spectrum of SnO2 / SnS2 / C composite; Figure 6 : EPR spectra of SnO2 / glucose, SnO2 / C, SnO2 / SnS2 / C, and SnS2 / C; Figure 7 : XPS spectra of SnO2 / C, SnO2 / SnS2 / C, and SnS2 / C composites; where (a) full XPS spectrum, (b) high-resolution XPS spectrum of Sn3d, (c) high-resolution XPS spectrum of S2p, (d) high-resolution XPS spectrum of O1s; Figure 8 : (a) Cycling performance of SnO2 / C, SnO2 / SnS2 / C, and SnS2 / C composites as anode materials for LIBs at a current density of 0.5 A g -1 current density; (b) Rate performance of SnO2 / C, SnO2 / SnS2 / C, and SnS2 / C composites as anode materials for LIBs at different current densities; Figure 9 : Cycling performance graph of SnO2 / SnS2 / C composite as anode material for LIBs at a current density of 5.0 A g -1 current density; Figure 10 : (a) Cycling performance of SnO2 / C, SnO2 / SnS2 / C, and SnS2 / C composites as anode materials for SIBs at a current density of 0.5 Ag -1 current density; (b) Rate performance of SnO2 / C, SnO2 / SnS2 / C, and SnS2 / C composites as anode materials for SIBs at different current densities; Figure 11 : Cycling performance graph of SnO2 / SnS2 / C composite as anode material for SIBs at a current density of 2.0 A g -1 current density. Detailed implementation mode

[0019] It should be noted that the following detailed description is illustrative and aims to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present application belongs.

[0020] As introduced in the background art section, optimizing and modifying the internal structure of tin-based materials through defect engineering is crucial for improving the electrochemical performance of electrode materials.

[0021] Based on this, the object of the present invention is to provide an oxygen and sulfur dual-vacancy modified SnO2 / SnS2 / C nanomaterial, its preparation method and application. The present invention uses a simple hydrothermal method to prepare a glucose-coated tin oxide nanoflower sphere (SnO2 / glucose) composite material. Subsequently, using sublimed sulfur as the sulfur source, under the protection of an inert gas, the above-obtained composite material is subjected to calcination and sulfidation treatment to prepare a carbon-coated oxygen and sulfur dual-vacancy modified tin dioxide composite tin disulfide nanoflower sphere (SnO2 / SnS2 / C) composite material. Although there are many reports currently on adding glucose in the preparation of SnO2 / C materials, glucose is used as a carbon source, and through calcination, glucose is carbonized and then coated on SnO2. However, in this application, not only is glucose used as a carbon source, but glucose is also used as an inducer to induce Sn6O4(OH)4 in the shape of an octahedron to self-assemble into a three-dimensional structure of SnO2 / glucose nanoflower spheres. In the hydrothermal reaction, under the action of glucose, more dispersed nanoflower spheres can be obtained, so that the nanoflower spheres do not agglomerate. In this way, the obtained SnO2 / glucose can contact the sulfur source more fully, and the distribution of SnO2 and SnS2 in the product obtained after calcination is more uniform, and the distribution of oxygen vacancies and sulfur vacancies is also more uniform, improving the energy storage performance of the material. In addition, the factors affecting the final performance of the product are as follows: (1) The dosage of the sulfur source: If the dosage of the sulfur source is too much, the final product obtained is only tin disulfide, and SnO2 / SnS2 / C with oxygen and sulfur dual-vacancies cannot be obtained. (2) The type of the precursor: SnO2 / glucose obtained by reacting K2SnO3•3H2O as the precursor with glucose is in an irregular block shape; SnO2 / glucose obtained by reacting SnCl2•2H2O as the precursor with glucose is in a stacked sheet structure. (3) The type of the carbon source: Without adding a carbon source, Sn6O4(OH)4 undergoes a hydrothermal reaction, and the product is in the shape of nanorods; using graphene as the carbon source, a structure of graphene sheets coating nanosheets is obtained; using sucrose as the carbon source, a structure of irregularly piled particles is obtained. And when the above structures are stacked together, even if oxygen vacancies and sulfur vacancies are obtained, they cannot be evenly distributed, or vacancies cannot be generated, seriously affecting the energy storage performance of the material as a negative electrode.

[0022] In order to enable those skilled in the art to more clearly understand the technical solution of the present application, the technical solution of the present application will be described in detail below in conjunction with specific embodiments.

[0023] The test materials used in the embodiments of the present invention are all conventional test materials in the art and can be obtained through commercial channels.

[0024] Example 1: Preparation of SnO2 / SnS2 / C (1) Add 0.5 g of stannous chloride dihydrate (SnCl2•2H2O) to 30 mL of anhydrous ethylenediamine solution, and perform ultrasonic dispersion for 30 min to obtain solution A. Then add 0.15 g of NaOH to 30 ml of aqueous solution, stir until completely dissolved to obtain solution B. Dropwise add solution B to solution A and stir for 1 h. Filter the obtained solution by suction and wash it 3 times with absolute ethanol. After drying in an oven at 60 °C, Sn6O4(OH)4 nanoparticles are obtained.

[0025] (2) Add 0.4 g of glucose and 0.25 g of PVP to 30 ml of distilled water, stir for 40 min to form a homogeneous solution. Add 0.1 g of Sn6O4(OH)4 prepared to the homogeneous solution, stir for 20 min, and perform ultrasonic dispersion for 30 min. Transfer the obtained solution to a 40 ml stainless steel autoclave lined with polytetrafluoroethylene, and carry out hydrothermal reaction at 180 °C for 6 h. After naturally cooling to room temperature, centrifuge the obtained precipitate and wash it 3 times, and then perform thermal drying at 80 °C to obtain a composite precursor of glucose-coated tin dioxide nanospheres, namely SnO2 / glucose.

[0026] (3) Take 0.15 g of SnO2 / glucose and 0.1 g of thioacetamide and place them in two different positions of an alumina porcelain boat. Place the porcelain boat in a tube furnace and calcine it at a heating rate of 5 °C / min under an argon atmosphere at 550 °C for 2 h. After naturally cooling to room temperature, a carbon-coated oxygen-sulfur double-vacancy modified SnO2 / SnS2 nanoflower sphere composite material, namely SnO2 / SnS2 / C, is obtained.

[0027] Example 2: Influence of Different Precursors on Hydrothermal Reaction Products Respectively use K2SnO3•3H2O or SnCl2•2H2O to replace Sn6O4(OH)4 and carry out hydrothermal reaction with glucose according to the method of step (2) of Example 1 to obtain SnO2 / glucose.

[0028] According to Figure 1It can be seen that the SnO2 / glucose obtained by the reaction of K2SnO3•3H2O or SnCl2•2H2O with glucose all exhibits a layered structure of stacked layers. This structure affects the subsequent reaction with the sulfur source. SnS2 can only be located on the surface of the material, while SnO2 is located inside the material, and it is impossible to form a SnO2-SnS2 heterostructure, let alone obtain SnO2 / SnS2 / C with a uniform distribution of oxygen vacancies and sulfur vacancies.

[0029] Example 3: Influence of the type of carbon source on the hydrothermal reaction product According to the method of step (2) in Example 1, without adding glucose or using graphene and sucrose instead of glucose as the carbon source respectively, the hydrothermal reaction product SnO2 / glucose was obtained.

[0030] According to Figure 2 It can be seen that when glucose is not added, only Sn6O4(OH)4 undergoes a hydrothermal reaction, and the product is a nanorod-like structure; when graphene is used as the carbon source, the morphology of SnO2 / glucose is a structure of graphene sheets coating nanosheets; when sucrose is used as the carbon source, the morphology of SnO2 / glucose is an irregular particle stacking structure. These structures all affect the sufficient contact with the sulfur source during subsequent calcination, and it is impossible to obtain a SnO2-SnS2 heterostructure, let alone obtain SnO2 / SnS2 / C with a uniform distribution of oxygen vacancies and sulfur vacancies.

[0031] Comparative Example 1: Preparation of SnO2 / C The difference from Example 1 is that thioacetamide is not added. Finally, a composite material coated with SnO2 nanospheres, that is, SnO2 / C (containing oxygen vacancies), was obtained.

[0032] Comparative Example 2: Preparation of SnS2 / C The difference from Example 1 is that 0.3 g of thioacetamide is added in excess. Finally, a carbon-coated SnS2 nanocomposite material, that is, SnS2 / C (containing sulfur vacancies), was obtained.

[0033] Example 4: Related characterizations The XRD patterns of SnO2 / glucose prepared in step (2) of Example 1, SnO2 / SnS2 / C prepared in Example 1, and SnO2 / C and SnS2 / C prepared in Comparative Examples 1-2 are as Figure 3 shown. By comparing with the standard cards, it can be found that SnO2 / SnS2 / C, SnO2 / glucose, SnO2 / C, and SnS2 / C were successfully prepared through Example 1 and Comparative Examples 1-2 respectively.

[0034] Figure 4The micro-morphologies and structures of SnO2 / glucose, SnO2 / SnS2 / C, SnO2 / C, and SnS2 / C prepared in Step (2) of Example 1, Example 1, and Comparative Examples 1-2. By Figure 4 It can be found from the SEM image in (a) that Sn6O4(OH)4 nanoparticles are self-assembled into three-dimensional SnO2 / glucose nanospheres induced by glucose during the hydrothermal reaction, with uniform size, and the diameter of the nanospheres is about 200 nm. And Figure 4 In (c), the basic structure of the obtained SnO2 / SnS2 / C nanocomposite after sulfuration treatment remains unchanged, but the particle size becomes larger. Figure 4 In (b), the SnO2 / C prepared in Comparative Example 1 is basically similar to the structure of SnO2 / glucose. Figure 4 In (d), agglomeration occurs in the SnS2 / C prepared in Comparative Example 2. The HRTEM image further shows that SnO2 / SnS2 / C has a three-dimensional porous spherical structure, and the diameter of the nanospheres is about 1 μm. The test results show that the nanosize becomes larger during the transformation from tin oxide to tin sulfide. Figure 4 In (f), it shows that there is a SnS2-SnO2 heterostructure in the SnO2 / SnS2 / C nanocomposite. The porous nanospheres assist the SnS2-SnO2 heterostructure, which is beneficial to increasing the active sites of the electrode material, alleviating the volume expansion of the electrode material, improving the structural stability of the electrode material, and thus enhancing the energy storage performance of the electrode material.

[0035] Figure 5 It is the energy spectrum diagram of the elements of SnO2 / SnS2 / C prepared in Example 1. The test results show that the SnO2 / SnS2 / C composite contains Sn, S, C, N, and O elements.

[0036] Figure 6EPR spectra of SnO2 / glucose, SnO2 / C, SnS2 / C, and SnO2 / SnS2 / C. Comparing SnO2 / glucose and SnO2 / C, SnO2 / glucose does not contain oxygen vacancies, while the g value of SnO2 / C is 2.002, indicating the presence of oxygen vacancies in SnO2 / C. These oxygen vacancies originate from the heat treatment process. After sulfidation treatment, the position of the EPR signal shifts because sulfur atoms replace oxygen atoms to form the SnS2 phase and sulfur vacancies are generated. The decrease in the EPR signal intensity is due to the decrease in the vacancy concentration when oxygen-rich SnO2 is converted to SnS2. For SnS2 / C, the EPR signal at a g value of 2.005 can be attributed to sulfur vacancies. For SnO2 / SnS2 / C, the g value is 2.004, which is between the g values of SnO2 / C and SnS2 / C, indicating the presence of both oxygen vacancies and sulfur vacancies in this sample. The synergistic effect of oxygen vacancies and sulfur vacancies will further provide more energy storage active sites, thereby improving the ion transport rate.

[0037] Figure 7 XPS survey spectra of SnO2 / C, SnS2 / C, and SnO2 / SnS2 / C, as well as high-resolution XPS spectra of Sn 3d, S 2p, and O 1s. Figure 7 In (a), it shows that SnO2 / C contains elements Sn, C, N, and O. While SnO2 / SnS2 / C and SnS2 / C prepared by sulfidation treatment contain elements Sn, S, C, N, and O. As Figure 7 shown in (b), for SnO2 / C, the two peaks at 495.5 eV and 487.1 eV can be attributed to Sn 3d 3 / 2 and Sn 3d 5 / 2 of SnO2. After sulfidation treatment, the surface chemical compositions of SnO2 / SnS2 / C and SnS2 / C are similar. The two pairs of peaks at 495.1 eV and 486.7 eV can be attributed to Sn 3d 3 / 2 and Sn3d 5 / 2 of SnS2. It should be noted that compared with SnO2 / C, these two peaks of SnO2 / SnS2 / C and SnS2 / C shift 0.4 eV towards lower binding energy, indicating the formation of S–Sn bonds after the sulfidation reaction. For Figure 7 the S2p spectra in (c), the two peaks at 161.6 eV and 162.9 eV in SnO2 / SnS2 / C and SnS2 / C correspond to S2p 3 / 2 and S2p 1 / 2 respectively, while the other peak at 164.5 eV may be attributed to the C–S–C bond. For Figure 7The O 1s spectra of (d) show that C–C / C=C, C–O, and O–C=O bonds are present in SnO2 / C, SnS2 / C, and SnO2 / SnS2 / C, while the Sn–C (284.3 eV) bond is found in SnO2 / SnS2 / C.

[0038] Experimental Example Using SnO2 / SnS2 / C prepared in Example 1 and SnO2 / C and SnS2 / C prepared in Comparative Examples 1 - 2 as active materials respectively, they were used to assemble batteries. The specific method is as follows: Using N-methyl-2-pyrrolidone (NMP) as the solvent, the active material, acetylene black, and polyvinylidene fluoride were mixed to form an electrode slurry in a mass ratio of 8:1:1, with the slurry just being able to flow. The mixed electrode slurry was evenly coated on a copper foil cleaned with alcohol using a coater, and after pre-drying, it was vacuum dried at 110 °C for 12 h in a vacuum oven, and then cut into circular pieces of a fixed size to be used as the negative electrode of lithium-ion batteries (LIBs) or sodium-ion batteries (SIBs).

[0039] When using the above materials as the negative electrode of lithium-ion batteries, 1 M LiPF6 was used as the electrolyte, where EC:DMC:EMC (1:1:1, wt%), containing 2.0% FEC. A polypropylene membrane (Celgard 2320) was used as the separator, and a pure lithium metal sheet was used as the counter electrode. The above materials were used as lithium-ion battery materials.

[0040] When using the above materials as the negative electrode materials of sodium-ion batteries, 1 M NaClO4 was used as the electrolyte, where EC:DEC (1:1, wt%), containing 5.0% FEC. A glass fiber (Whatman GF / D) was used as the separator, and a pure sodium metal sheet was used as the counter electrode. The above materials were used as sodium-ion battery materials.

[0041] The above two battery materials were assembled into 2032-type button batteries in a glove box filled with an Ar atmosphere (oxygen and moisture less than 1 ppm), using metal shrapnel and gaskets. A NEWARE battery measurement system was used for charge-discharge testing, with a cut-off voltage range of 3 V to 0.01 V, and the specific capacity obtained was calculated based on the total mass of the active material.

[0042] Figure 8 Cycling performance at a current density of 0.5 A g−1 and rate performance at different current densities for SnO2 / SnS2 / C, SnO2 / C, and SnS2 / C as negative electrode materials for LIBs. As can be seen from (a) in -1 it, at a current density of 0.5 A g−1, after 200 cycles, the capacity of the SnO2 / SnS2 / C electrode stabilized at 1122.6 mA h g Figure 8 in -1 −1.-1 . In contrast, the discharge capacities of the SnO2 / C electrode and the SnS2 / C electrode after 200 cycles are 257.4 mA h g -1 and 614.1 mA h g -1 . As can be seen from (b) in Figure 8 , when the current densities are 0.2 A g -1 , 0.5 A g -1 , 1.0 A g -1 , 2.0 A g -1 , 5.0 A g -1 , 10. A g -1 and 20.0 A g -1 respectively, the SnO2 / SnS2 / C electrode can maintain average reversible capacities of 1434.1 mA h g -1 , 1255.8 mA h g -1 , 1158.0 mA h g -1 , 1060.7 mAh g -1 , 827.0 mA h g -1 , 568.7 mA h g -1 and 358.9 mA h g -1 , which are much better than the performance of the SnO2 / C and SnS2 / C electrode materials. In particular, the SnO2 / SnS2 / C electrode is significantly superior to the SnO2 / C electrode and the SnS2 / C electrode in terms of high-rate performance. The SnO2 / C electrode and the SnS2 / C electrode show almost no capacity contribution at current densities of 10.0 A g -1 and 20.0 A g -1 . When the current density is restored to 0.2 A g -1 , the SnO2 / SnS2 / C can still maintain a capacity of 1293.0 mA h g -1 after 100 cycles, indicating its excellent rate performance. The above results show that the oxygen-sulfur double-vacancy synergistic SnO2 / SnS2 heterojunction modification strategy can effectively improve the lithium storage performance of electrode materials.

[0043] Figure 9 is the long-cycle performance graph of SnO2 / SnS2 / C as the anode material for LIBs. It can be seen that SnO2 / SnS2 / C can stably cycle 3200 times at a current density of 5.0 A g -1 , and the capacity can be maintained at 302.1 mA h g -1, The above results indicate that the SnO2 / SnS2 / C electrode material prepared by the oxygen-sulfur double vacancy synergistic SnO2 / SnS2 heterojunction modification strategy has excellent cycling performance in lithium storage. The high specific capacity and excellent cycling stability of the prepared SnO2 / SnS2 / C electrode are attributed to the construction of the SnS2 and SnO2 heterostructure and the introduction of sulfur / oxygen vacancies. The synergistic effect of the heterojunction and sulfur / oxygen vacancies plays an extremely important role in stabilizing the electrode structure, increasing active sites, and improving the lithium ion transport efficiency.

[0044] Figure 10 The cycling performance and rate performance at different current densities of SnO2 / SnS2 / C, SnO2 / C, and SnS2 / C as anode materials for SIBs at a current density of 0.5 A g -1 are shown in. Figure 10 The cycling performance shown in (a) indicates that the SnO2 / SnS2 / C electrode exhibits stable cycling performance. After cycling 100 times at a current density of 0.5 A g -1 , the capacity can be maintained at 548.4 mAh g -1 . In contrast, the cycling performance of SnO2 / C and SnS2 / C is poor. After cycling 100 times at the same test current, their capacities can only be maintained at 230.1 mA h g -1 and 131.9 mA h g -1 , respectively. Figure 10 The rate performance shown in (b) indicates that SnO2 / SnS2 / C can provide discharge specific capacities of 880.2 mA h g -1 , 611.7 mA h g -1 , 491.3 mA h g -1 , 391.5 mA h g -1 , 285.8 mA h g -1 , and 194.0 mA h g -1 at current densities of 0.2 - 10.0 A g -1 . The rate performance of the SnO2 / SnS2 / C electrode is superior to that of the SnO2 / C and SnS2 / C anodes. At a current density of 10 A g -1 , the reversible capacities provided by the SnO2 / C electrode and the SnS2 / C electrode are negligible. The above results indicate that the SnO2 / SnS2 / C electrode material prepared by the oxygen-sulfur double vacancy synergistic SnO2 / SnS2 heterojunction modification strategy has excellent cycling stability and rate performance in sodium storage.

[0045] Figure 11The graph shows the high-rate long-cycle performance of SnO2 / SnS2 / C as the anode material for SIBs. It can be seen that SnO2 / SnS2 / C can stably cycle 4300 times at a current density of 2.0 A g -1 and the capacity can be maintained at 171.9 mA h g -1 . The results prove that the SnO2 / SnS2 / C electrode prepared by the oxygen-sulfur double-vacancy synergistic SnO2 / SnS2 heterojunction modification strategy has excellent high-rate long-cycle sodium ion storage performance.

[0046] The above are only the preferred embodiments of the present application and are not used to limit the present application. For those skilled in the art, various changes and modifications can be made to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A preparation method of an oxygen and sulfur dual-vacancy modified SnO2 / SnS2 / C nanomaterial, characterized in that, It includes the following steps: (1) Mix the structure regulator with the tin salt, then dropwise add the alkali solution and stir. After suction filtration, a precipitate is obtained. The precipitate is dried to obtain tin oxide nanoparticles with an octahedral structure, namely Sn6O4(OH)4; (2) Add glucose and polyvinylpyrrolidone to distilled water, stir to form a homogeneous solution. Add Sn6O4(OH)4 to the homogeneous solution and stir, then perform ultrasonic treatment, and then carry out a hydrothermal reaction. After washing and drying, a glucose-coated tin oxide nanoflower sphere is obtained, namely SnO2 / glucose; (3) Mix SnO2 / glucose with a sulfur source and calcine it under an inert atmosphere. After cooling, an oxygen-sulfur double vacancy-modified SnO2 / SnS2 / C nanomaterial is obtained.

2. The preparation method according to claim 1, characterized in that, In step (1), the structure regulator is ethylenediamine or ethylene glycol; the tin salt is SnCl2•2H2O or SnCl4•5H2O; the alkali solution is a NaOH solution with a concentration of 0.12 mol / L to 0.17 mol / L.

3. The preparation method according to claim 1, characterized in that, In step (1), the stirring time is 30 to 120 min.

4. The preparation method according to claim 1, characterized in that, In step (2), the mass ratio of glucose, polyvinylpyrrolidone and Sn6O4(OH)4 is 3 to 5: 2 to 5: 1 to 3; the concentration of glucose in the homogeneous solution is 0.01 g / mL.

5. The preparation method according to claim 1, characterized in that, In step (2), the stirring time is 20 min; the power of the ultrasonic treatment is 400 W, and the ultrasonic treatment time is 60 min; the temperature of the hydrothermal reaction is 150 to 200 °C, and the hydrothermal reaction time is 4 to 8 h.

6. The preparation method according to claim 1, characterized in that, In step (3), the sulfur source is sulfur powder, thioacetamide or sodium hydrosulfide; the mass ratio of SnO2 / glucose and the sulfur source is 3:2; the inert atmosphere is argon or nitrogen.

7. The preparation method according to claim 1, characterized in that, In step (3), the heating rate of the calcination is 2 to 5 °C / min, the calcination temperature is 350 to 550 °C, and the calcination time is 1 to 3 h.

8. The oxygen-sulfur double vacancy modified SnO2 / SnS2 / C nanomaterial obtained by the preparation method according to any one of claims 1 to 7, characterized in that, In the oxygen-sulfur double vacancy-modified SnO2 / SnS2 / C nanomaterial, SnO2 has oxygen vacancies and SnS2 has sulfur vacancies.

9. Application of the oxygen-sulfur double vacancy-modified SnO2 / SnS2 / C nanomaterial according to claim 1 or 2 in the preparation of a sodium ion battery or a lithium ion battery.

10. The application according to claim 9, wherein The application is that the oxygen-sulfur double vacancy-modified SnO2 / SnS2 / C nanomaterial is used as an anode material to improve the specific capacity, cycle stability and rate performance of a sodium ion battery or a lithium ion battery.

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