SnO2 / SnS2 / C nanomaterial modified with oxygen and sulfur divacancy, preparation method and application thereof

Abstract

The present invention discloses a SnO2 / SnS2 / C nanomaterial modified with oxygen and sulfur divacancy, and its preparation method and application, belonging to the technical field of electrode materials. A structure regulating agent is mixed with a tin salt, alkali solution is added dropwise and stirred, and Sn6O4(OH)4 is obtained by suction filtration; glucose and polyvinyl pyrrolidone are added to distilled water and stirred to form a uniform solution, Sn6O4(OH)4 is added to the uniform solution and stirred, ultrasonicated, and subjected to hydrothermal reaction to obtain SnO2 / glucose; SnO2 / glucose is calcined with a sulfur source under an inert atmosphere to obtain SnO2 / SnS2 / C nanomaterial modified with oxygen and sulfur divacancy. The SnO2 / SnS2 / C of the present invention is used for the negative electrode of lithium / sodium ion batteries, can effectively alleviate the volume expansion of tin-based oxysulfides, improve the conductivity of the electrode material, and exhibit high charge and discharge specific capacity, excellent rate performance, and high rate long cycle stability.

Description

Technical Field

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

[0002] The birth of secondary batteries has greatly reduced the world's dependence on fossil fuels. Among them, lithium-ion batteries (LIBs) have profoundly changed human lifestyles with their wide application and have played an extremely important role in promoting green and sustainable development. However, the reserves of lithium resources are limited. In this context, sodium-ion batteries (SIBs) have become a powerful supplement to lithium-ion batteries due to their abundant reserves. Graphite has excellent conductivity and high specific surface area, which makes it widely concerned in lithium-ion batteries and sodium-ion batteries, and has become a commonly used candidate negative electrode material for this type of battery. However, with the development of society, the demand for high energy density is increasing day by day, and the shortcomings of current graphite-based negative electrode materials are becoming more and more obvious. Its theoretical capacity is only 372 mA hg -1 , it is difficult to meet the ever-increasing performance requirements, and new breakthroughs are urgently needed.

[0003] Tin-based (Sn) electrode materials have attracted the attention of many researchers due to their excellent energy storage potential and have become the research focus in the field of negative electrode materials for lithium-ion batteries and sodium-ion batteries. However, this type of electrode material will experience significant volume changes and rapid capacity decay during the charge and discharge cycle, which seriously hinders its transition from laboratory to large-scale commercial application. As an important branch of tin-based materials, tin-based oxides have been favored by many researchers and have become the focus of exploration due to their advantages such as high theoretical capacity, abundant resources and environmental friendliness. Studies have found that SnO2, as a lithium / sodium storage negative electrode, has a high capacity. However, at present, how to design and prepare SnO2-based electrode materials that have both high rate performance and long-term cycle stability and are suitable for both lithium / sodium storage is still a problem that needs to be solved urgently. Patent application number CN108539136A discloses a method for preparing tin sulfide / nitrogen-doped carbon composite flower balls and their application in lithium-ion battery negative electrodes; patent application number CN109935804A discloses a long-life tin sulfide negative electrode material and its preparation method; patent application number CN114804190A discloses a method for size-homogenizing SnO2 / SnS2 flower-shaped micron-sized particles; and patent application number CN114988419A discloses SiO2 / SnSe / C nanospheres and their preparation method. These methods improve the energy storage performance of tin-based materials through elemental doping or by combining tin oxide with other selenides or oxides. However, there are no reports on improving energy storage performance through defect treatment of tin-based materials. Optimizing and modifying the internal structure of tin-based materials through defect engineering is crucial for improving the electrochemical performance of electrode materials. However, the challenge of ingeniously constructing a reasonable defect structure to achieve high capacity while ensuring stable cycling performance remains. Summary of the Invention

[0004] In response to the above-mentioned prior art, the present invention aims to provide a SnO2 / SnS2 / C nanomaterial modified with oxygen and sulfur divacancies, as well as its preparation method and application. This invention utilizes a simple hydrothermal method to prepare a glucose-coated tin oxide nanosphere (SnO2 / glucose) composite material. Sublimated sulfur is then used as the sulfur source and calcined under inert gas to produce a carbon-coated tin dioxide-tin disulfide nanosphere (SnO2 / SnS2 / C) composite material modified with oxygen and sulfur divacancies. This nanomaterial, used in lithium / sodium ion battery anodes, effectively mitigates the volume expansion of tin-based oxysulfides, improves electrode material conductivity, and exhibits high charge-discharge capacity, excellent rate performance, and high-rate, long-cycle stability.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] The first aspect of the present invention provides a method for preparing SnO2 / SnS2 / C nanomaterials modified with oxygen and sulfur divacancy, comprising the following steps:

[0007] (1) Mixing a structure modifier with a tin salt, then adding an alkaline solution and stirring, filtering to obtain a precipitate, and drying the precipitate to obtain tin oxide nanoparticles with an octahedral structure, namely Sn6O4(OH)4;

[0008] (2) Glucose and polyvinyl pyrrolidone are added to distilled water and stirred to form a homogeneous solution. Sn6O4(OH)4 is added to the homogeneous solution and stirred, and then ultrasonically treated. Then, a hydrothermal reaction is carried out, and after washing and drying, glucose-coated tin oxide nanospheres are obtained, namely SnO2 / glucose.

[0009] (3) SnO2 / glucose is mixed with a sulfur source, calcined under an inert atmosphere, and cooled to obtain SnO2 / SnS2 / C nanomaterials modified with oxygen and sulfur divacancies.

[0010] Preferably, in step (1), the structure regulating agent is ethylenediamine or ethylene glycol; the tin salt is SnCl2•2H2O or SnCl4•5H2O; and the alkali solution is NaOH solution with a concentration of 0.12 mol / L to 0.17 mol / L.

[0011] Preferably, in step (1), the stirring time is 30 to 120 minutes.

[0012] Preferably, in step (2), the mass ratio of glucose, polyvinyl pyrrolidone and Sn6O4(OH)4 is 3-5:2-5:1-3; and the concentration of glucose in the homogeneous solution is 0.01 g / mL.

[0013] Preferably, in step (2), the stirring time is 20 minutes; the ultrasonic treatment power is 400W, and the ultrasonic treatment time is 60 minutes; the hydrothermal reaction temperature is 150-200°C, and the hydrothermal reaction time is 4-8 hours.

[0014] Preferably, in step (3), the sulfur source is sulfur powder, thioacetamide or sodium hydrosulfide; the mass ratio of SnO2 / glucose to the sulfur source is 3:2; and the inert atmosphere is argon or nitrogen.

[0015] Preferably, in step (3), the calcination heating rate is 2-5°C / min, the calcination temperature is 350-550°C, and the calcination time is 1-3h.

[0016] The second aspect of the present invention provides an oxygen-sulfur divacancy modified SnO2 / SnS2 / C nanomaterial obtained by the above-mentioned preparation method, in which SnO2 has oxygen vacancies and SnS2 has sulfur vacancies.

[0017] The SnO2 / SnS2 / C nanomaterial modified with oxygen and sulfur divacancy has a porous hollow nano-flower spherical structure with a size of 500nm~2μm.

[0018] The third aspect of the present invention provides the use of SnO2 / SnS2 / C nanomaterials modified with oxygen and sulfur divacancy in the preparation of sodium ion batteries or lithium ion batteries.

[0019] Preferably, the application is that SnO2 / SnS2 / C nanomaterial modified with oxygen-sulfur divacancy is used as a negative electrode material to improve the specific capacity, cycle stability and rate performance of sodium ion batteries or lithium ion batteries.

[0020] Beneficial effects of the present invention:

[0021] (1) The present invention adopts a novel preparation method and innovatively utilizes glucose to induce the self-assembly reaction of octahedral Sn6O4(OH)4 to obtain a SnO2 / glucose nano-flower ball composite material with a three-dimensional hollow structure. The composite material is used as a precursor for sulfurization modification. By regulating the material ratio of the precursor to the sulfur source, oxygen vacancies and sulfur vacancies can be introduced simultaneously, and a SnO2-SnS2 heterostructure can be constructed simultaneously. The resulting SnO2 / SnS2 / C has regular size and uniform distribution. The unique hollow nano-flower ball structure can alleviate the volume expansion during the energy storage process and provide ion transmission channels, so that the electrode material has excellent rate performance and long cycle performance.

[0022] (2) The oxygen-sulfur divacancy 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 alleviate the volume expansion of the electrode material during energy storage, enhance the structural stability of the electrode material, and synergize with the three-dimensional hollow nanosphere structure to significantly improve the energy storage performance of the electrode material. It is expected to achieve high-rate and long cycle life for lithium / sodium ion batteries. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 :(a) Morphology of SnO2 / glucose composite material prepared by reacting K2SnO3•3H2O as tin source with glucose, (b) Morphology of SnO2 / glucose composite material prepared by reacting SnCl2•2H2O as tin source with glucose;

[0024] Figure 2:(a) Morphological structure of Sn6O4(OH)4 after hydrothermal reaction for 6 hours without adding glucose as carbon source;(b) Morphological structure of Sn6O4(OH)4 after hydrothermal reaction for 6 hours with graphene as carbon source;(c) Morphological structure of Sn6O4(OH)4 after hydrothermal reaction for 6 hours with sucrose as carbon source;

[0025] Figure 3 : XRD patterns of SnO2 / C, SnO2 / SnS2 / C and SnS2 / C nanocomposites;

[0026] Figure 4 : Micromorphology and structure of SnO2 / glucose, SnO2 / C, SnO2 / SnS2 / C and SnS2 / C nanocomposites; (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;

[0027] Figure 5 : Elemental energy spectrum of SnO2 / SnS2 / C composite material;

[0028] Figure 6 : EPR spectra of SnO2 / glucose, SnO2 / C, SnO2 / SnS2 / C and SnS2 / C;

[0029] Figure 7 : XPS spectra of SnO2 / C, SnO2 / SnS2 / C and SnS2 / C composites; (a) XPS full spectrum, (b) high-resolution XPS spectrum of Sn3d, (c) high-resolution XPS spectrum of S2p, (d) high-resolution XPS spectrum of O1s;

[0030] Figure 8 :(a) SnO2 / C, SnO2 / SnS2 / C and SnS2 / C composites as LIBs anode materials at 0.5 A g -1 Cycling performance at different current densities; (b) Rate performance of SnO2 / C, SnO2 / SnS2 / C and SnS2 / C composites as LIBs anode materials at different current densities;

[0031] Figure 9 SnO2 / SnS2 / C composites as LIBs negative electrode materials at 5.0 A g -1 Cycling performance diagram under current density;

[0032] Figure 10 :(a) SnO2 / C, SnO2 / SnS2 / C and SnS2 / C composites as SIBs anode materials at 0.5 Ag -1 Cycling performance at different current densities; (b) Rate performance of SnO2 / C, SnO2 / SnS2 / C and SnS2 / C composites as SIBs anode materials at different current densities;

[0033] Figure 11 SnO2 / SnS2 / C composites as SIBs anode materials at 2.0 A g -1 Cycling performance diagram under different current densities. DETAILED DESCRIPTION

[0034] It should be noted that the following detailed descriptions are illustrative and intended 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 skilled in the art to which the present application belongs.

[0035] As introduced in the background technology section, optimizing and modifying the internal structure of tin-based materials through defect engineering is crucial to improving the electrochemical properties of electrode materials.

[0036] Based on this, the present invention aims to provide a SnO2 / SnS2 / C nanomaterial modified with oxygen and sulfur divacancies, as well as its preparation method and application. The present invention utilizes a simple hydrothermal method to prepare a glucose-coated tin oxide nanosphere (SnO2 / glucose) composite material. The resulting composite material is then calcined and sulfurized under inert gas protection using sublimated sulfur as the sulfur source to produce a carbon-coated tin dioxide-composite tin disulfide nanosphere (SnO2 / SnS2 / C) composite material modified with oxygen and sulfur divacancies. Although many reports have reported the addition of glucose to the preparation of SnO2 / C materials, these materials all use glucose as the carbon source, carbonizing the glucose through calcination and subsequently coating it on the SnO2. However, the present invention not only utilizes glucose as the carbon source but also uses glucose as an inducer to induce the self-assembly of octahedral Sn6O4(OH)4 into three-dimensional SnO2 / glucose nanospheres. During the hydrothermal reaction, under the action of glucose, more dispersed nanospheres can be obtained, so that the nanospheres do not agglomerate. In this way, the obtained SnO2 / glucose can be more fully in contact with the sulfur source. After calcination, the distribution of SnO2 and SnS2 in the product is more uniform, and the distribution of oxygen vacancies and sulfur vacancies is also more uniform, which improves the energy storage performance of the material. In addition, the factors that affect the final performance of the product are as follows: (1) The amount of sulfur source: If the amount of sulfur source is too much, the final product obtained is only tin disulfide, and SnO2 / SnS2 / C with oxygen and sulfur double vacancies cannot be obtained. (2) The type of precursor: The SnO2 / glucose obtained by reacting K2SnO3•3H2O as a precursor with glucose is irregular block; the SnO2 / glucose obtained by reacting SnCl2•2H2O as a precursor with glucose is a stacked layer structure. (3) Type of carbon source: When no carbon source is added, Sn6O4(OH)4 undergoes a hydrothermal reaction, resulting in a nanorod-like product. When graphene is used as a carbon source, a graphene sheet-coated nanosheet structure is obtained. When sucrose is used as a carbon source, a structure of irregular particle stacking is obtained. However, when these structures are stacked together, even if oxygen and sulfur vacancies are obtained, they cannot be evenly distributed, or vacancies cannot be generated, which seriously affects the energy storage performance of the material when used as a negative electrode.

[0037] 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 with reference to specific embodiments.

[0038] The test materials used in the examples of the present invention are all conventional test materials in the art and can be purchased through commercial channels.

[0039] Example 1: Preparation of SnO2 / SnS2 / C

[0040] (1) Add 0.5 g of stannous chloride dihydrate (SnCl2•2H2O) to 30 mL of anhydrous ethylenediamine solution and ultrasonically disperse for 30 min to obtain solution A. Then, add 0.15 g of NaOH to 30 mL of aqueous solution and stir until completely dissolved to obtain solution B. Solution B was added dropwise to solution A and stirred for 1 h. The obtained solution was filtered and washed three times with anhydrous ethanol. After drying in an oven at 60°C, Sn6O4(OH)4 nanoparticles were obtained.

[0041] (2) Add 0.4 g glucose and 0.25 g PVP to 30 ml distilled water and stir for 40 min to form a uniform solution. Add 0.1 g Sn6O4(OH)4 prepared to the uniform solution, stir for 20 min, and ultrasonically disperse for 30 min. Transfer the obtained solution to a 40 ml stainless steel autoclave lined with polytetrafluoroethylene and hydrothermally react at 180 ° C for 6 h. After cooling naturally to room temperature, the obtained precipitate is centrifuged and washed 3 times, and then dried at 80 ° C to obtain the glucose-coated tin dioxide nanosphere composite material precursor, namely SnO2 / glucose.

[0042] (3) 0.15 g of SnO2 / glucose and 0.1 g of thioacetamide were placed at two different locations on an alumina boat. The boat was placed in a tube furnace and calcined at 550°C for 2 h at a heating rate of 5°C / min under an argon atmosphere. After cooling naturally to room temperature, a carbon-coated SnO2 / SnS2 nanosphere composite material modified with oxygen and sulfur divacancies, namely SnO2 / SnS2 / C, was obtained.

[0043] Example 2: Effects of different precursors on hydrothermal reaction products

[0044] Sn6O4(OH)4 was replaced by K2SnO3•3H2O or SnCl2•2H2O, and subjected to hydrothermal reaction with glucose according to the method of step (2) of Example 1 to obtain SnO2 / glucose.

[0045] according to Figure 1 It can be seen that the SnO2 / glucose obtained by the reaction of K2SnO3•3H2O or SnCl2•2H2O with glucose presents a layered structure. 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. It is impossible to form a SnO2-SnS2 heterogeneous structure, and it is even impossible to obtain SnO2 / SnS2 / C with uniform distribution of oxygen vacancies and sulfur vacancies.

[0046] Example 3: Effect of carbon source type on hydrothermal reaction products

[0047] According to the method of step (2) of Example 1, no glucose is added or graphene and sucrose are used instead of glucose as the carbon source to obtain the hydrothermal reaction product SnO2 / glucose.

[0048] 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 SnO2 / glucose morphology is a graphene sheet-coated nanosheet structure. When sucrose is used as the carbon source, the SnO2 / glucose morphology 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 a SnO2 / SnS2 / C with uniform distribution of oxygen and sulfur vacancies.

[0049] Comparative Example 1: Preparation of SnO2 / C

[0050] The difference from Example 1 is that thioacetamide is not added. Finally, a composite material coated with SnO2 nano-flower balls, namely SnO2 / C (containing oxygen vacancies), is obtained.

[0051] Comparative Example 2: Preparation of SnS2 / C

[0052] The difference from Example 1 is that 0.3 g of thioacetamide was added in excess, and finally a carbon-coated SnS2 nanocomposite material, namely SnS2 / C (containing sulfur vacancies), was obtained.

[0053] Example 4: Related Characterization

[0054] 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 and 2 are as follows: Figure 3 As shown, by comparing with the standard card, it can be found that SnO2 / SnS2 / C, SnO2 / glucose, SnO2 / C, and SnS2 / C were successfully prepared by Example 1 and Comparative Examples 1~2, respectively.

[0055] Figure 4 The micromorphology and structure 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. Figure 4 In the SEM image (a), it can be found that Sn6O4(OH)4 nanoparticles are induced by glucose to self-assemble into three-dimensional SnO2 / glucose nanospheres during the hydrothermal reaction. The size of the nanospheres is uniform and the diameter of the nanospheres is about 200 nm. Figure 4(c) The basic structure of the SnO2 / SnS2 / C nanocomposite obtained by sulfurization treatment remains unchanged, but the particle size becomes larger. Figure 4 The SnO2 / C prepared in Comparative Example 1 (b) is similar in structure to SnO2 / glucose. Figure 4 In (d), the SnS2 / C prepared in Comparative Example 2 exhibits agglomeration. HRTEM images further reveal that the SnO2 / SnS2 / C exhibits a three-dimensional porous spherical structure, with nanospheres approximately 1 μm in diameter. This indicates that the nanospheres increase in size during the conversion from tin oxide to tin sulfide. Figure 4 (f) shows the presence of a SnS2-SnO2 heterostructure in the SnO2 / SnS2 / C nanocomposite. The porous nanosphere-assisted SnS2-SnO2 heterostructure increases the number of active sites in the electrode material, mitigates volume expansion, and improves its structural stability, thereby enhancing its energy storage performance.

[0056] Figure 5 This is the element energy spectrum of SnO2 / SnS2 / C prepared in Example 1. The test results show that the SnO2 / SnS2 / C composite material contains Sn, S, C, N, and O elements.

[0057] Figure 6 Electron paramagnetic resonance (EPR) spectra of SnO2 / glucose, SnO2 / C, SnS2 / C, and SnO2 / SnS2 / C are shown. A comparison of SnO2 / glucose and SnO2 / C reveals that SnO2 / glucose contains no oxygen vacancies, while SnO2 / C exhibits a g value of 2.002, indicating the presence of oxygen vacancies in SnO2 / C. These oxygen vacancies originate from the heat treatment. After sulfurization, the EPR signal shifts in position due to sulfur atoms replacing oxygen atoms, forming the SnS2 phase and generating sulfur vacancies. The decrease in EPR signal intensity is attributed to a decrease in vacancy concentration when oxygen-vacancy-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. The g value of SnO2 / SnS2 / C is 2.004, which is between the g values ​​of SnO2 / C and SnS2 / C, indicating the presence of both oxygen and sulfur vacancies in this sample. The synergistic effect of oxygen and sulfur vacancies will further provide more active sites for energy storage, thereby improving the ion transport rate.

[0058] Figure 7 These are the full XPS spectra of SnO2 / C, SnS2 / C and SnO2 / SnS2 / C, as well as the high-resolution XPS spectra of Sn3d, S2p and O1s. Figure 7(a) shows that SnO2 / C contains elements Sn, C, N and O. However, SnO2 / SnS2 / C and SnS2 / C prepared by sulfidation treatment contain elements Sn, S, C, N and O. Figure 7 As shown in (b), for SnO2 / C, the two peaks at 495.5eV and 487.1eV can be attributed to the Sn 3d 3 / 2 and Sn 3d 5 / 2 After sulfidation, the surface chemical compositions of SnO2 / SnS2 / C and SnS2 / C are similar, and the two pairs of peaks at 495.1 eV and 486.7 eV can be attributed to the Sn 3d 3 / 2 and Sn3d 5 / 2 It is worth noting that the two peaks of SnO2 / SnS2 / C and SnS2 / C shifted to lower binding energy by 0.4 eV compared with SnO2 / C, indicating that S–Sn bonds were formed after the sulfurization reaction. Figure 7 In the S2p spectrum in (c), the two peaks at 161.6 eV and 162.9 eV in SnO2 / SnS2 / C and SnS2 / C correspond to the S2p 3 / 2 and S2p 1 / 2 , while the other peak at 164.5 eV may be attributed to the C–S–C bond. Figure 7 In the O1s energy spectrum in (d), C–C / C=C, C–O and O–C=O bonds exist in SnO2 / C, SnS2 / C and SnO2 / SnS2 / C, while Sn–C (284.3 eV) bond is found in SnO2 / SnS2 / C.

[0059] Test example

[0060] The SnO2 / SnS2 / C prepared in Example 1 and the SnO2 / C and SnS2 / C prepared in Comparative Examples 1 and 2 were used as active materials to assemble batteries. The specific method was as follows:

[0061] Using N-methyl-2-pyrrolidine (NMP) as a solvent, the active material, acetylene black, and polyvinylidene fluoride are mixed in a mass ratio of 8:1:1 to form an electrode slurry, ideally allowing the slurry to just flow. The mixed electrode slurry is evenly coated onto alcohol-cleaned copper foil using an applicator. After pre-drying, the slurry is vacuum-dried in a 110°C oven for 12 hours. The slurry is then cut into discs of fixed size using a cutting machine to serve as negative electrodes for lithium-ion batteries (LIBs) or sodium-ion batteries (SIBs).

[0062] When the above materials are used as the negative electrode of a lithium-ion battery, 1M LiPF6 is used as the electrolyte, with a ratio of EC:DMC:EMC (1:1:1, wt%), and 2.0% FEC. A polypropylene film (Celgard 2320) is used as the separator, and a pure lithium metal sheet is used as the counter electrode. The above materials are used as lithium-ion battery materials.

[0063] When the above materials are used as the negative electrode materials for sodium-ion batteries, 1M NaClO₄ is used as the electrolyte, with a 1:1 wt% ratio of EC:DEC and 5.0% FEC. A glass fiber (Whatman GF / D) is used as the separator, and a pure sodium metal sheet is used as the counter electrode. The above materials are used as sodium-ion battery materials.

[0064] The two battery materials were assembled into 2032-type button cells in a glove box filled with an Ar atmosphere (oxygen and moisture less than 1 ppm), using metal domes and spacers. Charge and discharge tests were performed using a NEWARE battery measurement system with a cutoff voltage range of 3V to 0.01V. The specific capacity was calculated based on the total mass of the active materials.

[0065] Figure 8 When SnO2 / SnS2 / C, SnO2 / C, SnS2 / C are used as LIBs negative electrode materials at 0.5Ag -1 Cycling performance at different current densities and rate performance at different current densities. Figure 8 As shown in (a), at 0.5Ag -1 At this current density, the capacity of the SnO2 / SnS2 / C electrode stabilized at 1122.6 mA h g after 200 cycles. -1 In comparison, the discharge capacities of the SnO2 / C electrode and SnS2 / C electrode after 200 cycles were 257.4 mA h g -1 and 614.1 mA hg -1 .Depend on Figure 8 As shown in (b), when the current density is 0.2A g -1 , 0.5A g -1 , 1.0A g -1 , 2.0A g -1 , 5.0A g -1 、10. A g -1 and 20.0A g -1 When SnO2 / SnS2 / C electrodes can maintain 1434.1mA hg -1 、1255.8mA hg -1 、1158.0mA hg -1 、1060.7mAh g -1、827.0mA hg -1 、568.7mA hg -1 and 358.9mA hg -1 The average reversible capacity of SnO2 / C and SnS2 / C electrodes is much better than that of SnO2 / C and SnS2 / C electrode materials. In particular, the SnO2 / SnS2 / C electrode is significantly better than that of SnO2 / C and SnS2 / C electrodes in terms of high rate performance. -1 and 20.0A g -1 There is almost no capacity contribution at the current density of 0.2A g -1 When SnO2 / SnS2 / C was used for 100 cycles, it could still maintain 1293.0 mA hg -1 The above results indicate that the oxygen-sulfur divacancy synergistic SnO2 / SnS2 heterojunction modification strategy can effectively improve the lithium storage performance of electrode materials.

[0066] Figure 9 The long cycle performance diagram of SnO2 / SnS2 / C as LIBs negative electrode material shows that SnO2 / SnS2 / C has a good cycling performance at 5.0A g -1 It can stably cycle 3200 times at the current density, and the capacity can be maintained at 302.1 mA hg -1 The above results indicate that the SnO2 / SnS2 / C electrode material prepared by the SnO2 / SnS2 heterojunction modification strategy with oxygen and sulfur vacancies exhibits excellent cycling performance in terms of 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 lithium ion transport efficiency.

[0067] Figure 10 When SnO2 / SnS2 / C, SnO2 / C, and SnS2 / C are used as negative electrode materials for SIBs, the -1 Cycling performance at different current densities and rate performance at different current densities. Figure 10 The cycling performance shown in (a) shows that the SnO2 / SnS2 / C electrode exhibits stable cycling performance at 0.5 A g -1 After 100 cycles at a current density of 1.5 mAh g, the capacity can be maintained at 548.4 mAh g -1In contrast, the cycling performance of SnO2 / C and SnS2 / C is poor. After 100 cycles at the same test current, their capacities can only be maintained at 230.1 mA h g -1 and 131.9 mA hg -1 . Figure 10 (b) Rate performance shows that SnO2 / SnS2 / C has a high performance in the range of 0.2-10.0A g -1 The current density can provide 880.2mA hg -1 、611.7 mA hg -1 、491.3mA hg -1 、391.5mA hg -1 、285.8mA hg -1 and 194.0mA hg -1 The discharge capacity of SnO2 / SnS2 / C electrode is better than that of SnO2 / C and SnS2 / C negative electrodes. -1 At a current density of 1.5 Å, the reversible capacity provided by the SnO2 / C electrode and the SnS2 / C electrode is negligible. The above results indicate that the SnO2 / SnS2 / C electrode material prepared by the oxygen-sulfur divacancy synergistic SnO2 / SnS2 heterojunction modification strategy has excellent cycling stability and rate performance in sodium storage.

[0068] Figure 11 The high rate and long cycle performance of SnO2 / SnS2 / C as the negative electrode material of SIBs is shown in Figure 2. It can be seen that SnO2 / SnS2 / C has a high rate and long cycle performance at 2.0A g -1 It can stably cycle 4300 times at the current density, and the capacity can be maintained at 171.9 mA h g -1 The results show that the SnO2 / SnS2 / C electrode prepared by the oxygen-sulfur double vacancy synergistic SnO2 / SnS2 heterojunction modification strategy has excellent high-rate and long-cycle sodium ion storage performance.

[0069] The above description is merely a preferred embodiment of the present application and is not intended to limit the present application. Various modifications and variations are possible for those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. An oxygen-sulfur divacancy modified SnO2 / SnS2 / C nanomaterial, characterized in that: In the oxygen-sulfur double vacancy modified SnO2 / SnS2 / C nanomaterial, SnO2 has oxygen vacancies and SnS2 has sulfur vacancies; The SnO2 / SnS2 / C nanomaterial modified with oxygen and sulfur divacancy is prepared by the following method: (1) A structure regulating agent and a tin salt are mixed, and then an alkali solution is added dropwise and stirred. A precipitate is obtained by filtration, and the precipitate is dried to obtain tin oxide nanoparticles having an octahedral structure, namely, Sn6O4(OH)4; the tin salt is SnCl2•2H2O or SnCl4•5H2O; the structure regulating agent is ethylenediamine or ethylene glycol; the alkali solution is a NaOH solution, and its concentration is 0.12 mol / L~0.17 mol / L; (2) Glucose and polyvinyl pyrrolidone are added to distilled water and stirred to form a homogeneous solution, Sn6O4(OH)4 is added to the homogeneous solution and stirred, and then ultrasonically treated, followed by hydrothermal reaction, washed and dried to obtain glucose-coated tin oxide nanospheres, i.e., SnO2 / glucose; the mass ratio of the glucose, polyvinyl pyrrolidone and Sn6O4(OH)4 is 3-5:2-5:1-3; the concentration of glucose in the homogeneous solution is 0.01 g / mL; (3) Mixing SnO2 / glucose with a sulfur source, calcining under an inert atmosphere, and cooling to obtain an oxygen-sulfur divacancy modified SnO2 / SnS2 / C nanomaterial; the sulfur source is sulfur powder, thioacetamide or sodium hydrosulfide; the mass ratio of the SnO2 / glucose and the sulfur source is 3:2; and the inert atmosphere is argon or nitrogen.

2. The SnO2 / SnS2 / C nanomaterial according to claim 1, characterized in that In step (1), the stirring time is 30 to 120 minutes.

3. The SnO2 / SnS2 / C nanomaterial according to claim 1, characterized in that In step (2), the stirring time is 20 minutes; the power of the ultrasonic treatment is 400W, and the ultrasonic treatment time is 60 minutes; the temperature of the hydrothermal reaction is 150-200°C, and the hydrothermal reaction time is 4-8 hours.

4. The SnO2 / SnS2 / C nanomaterial according to claim 1, characterized in that In step (3), the calcination heating rate is 2-5°C / min, the calcination temperature is 350-550°C, and the calcination time is 1-3h.

5. Use of the SnO2 / SnS2 / C nanomaterial modified with oxygen and sulfur divacancy according to any one of claims 1 to 4 in the preparation of sodium ion batteries or lithium ion batteries.

6. The use according to claim 5, characterized in that The application is to use SnO2 / SnS2 / C nanomaterials modified with oxygen and sulfur divacancy as negative electrode materials to improve the specific capacity, cycle stability and rate performance of sodium ion batteries or lithium ion batteries.

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